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ORIENTED MULTILAYER SHRINK FILMS WITH POLYSTYRENE SKIN LAYER

20220396059 · 2022-12-15

    Inventors

    Cpc classification

    International classification

    Abstract

    Multilayer oriented shrink films include a skin layer and a base layer; the skin layer being on one side of the base layer, characterized in that the skin layer comprises at least one amorphous styrene-butadiene block copolymer and the base layer has a thickness greater than said skin layer and includes a polypropylene terpolymer, a polybutene-1 copolymer, a polypropylene elastomeric copolymer and at least one copolymer from the group consisting of styreneethylene/butene-styrene triblock copolymers, styrene-ethylene/propylene-styrene triblock copolymers, styrene-ethylene/butene diblock copolymers, styrene-ethylene-propylene diblock copolymers, and combinations of two or more of said triblock and diblock copolymers.

    Claims

    1-16. (canceled)

    17. A multilayer oriented shrink film comprising: A) a core layer comprising: i) at least one polypropylene co- or terpolymer selected from the group consisting of polypropylene terpolymers with ethylene and butene-1, propylene ethylene copolymers, propylene butene-1 copolymers and combinations thereof, ii) at least one polybutene-1 copolymer, iii) at least one polypropylene elastomeric copolymer, and iv) optionally at least one polymer selected from the group consisting of styrene-ethylene-co-propylene-styrene-ethylene-co-propylene tetrablock, styrene-ethylene-co-butene-styrene triblock copolymers, styrene-ethylene-co-propylene-styrene triblock copolymers, styrene-ethylene-co-butene diblock copolymers, styrene-ethylene-co-propylene diblock copolymers and combinations thereof; and B) at least one skin layer on a first side of said core layer; and wherein said at least one skin layer comprises at least 80 wt. % of at least one amorphous styrene-butadiene block copolymer, and wherein said core layer has a thickness greater than said at least one skin layer, the film has a haze less than 6%, and optionally wherein said film is corona treated.

    18. (canceled)

    19. The multilayer oriented shrink film of claim 17, wherein said core layer comprises: 36 wt. % to 40 wt. % of the at least one polypropylene co- or terpolymer selected from the group consisting of polypropylene terpolymers with ethylene and butene-1, propylene ethylene copolymers, propylene butene-1 copolymers and combinations thereof 20 wt. % to 27 wt. % of the at least one polybutene-1 copolymer, 20 wt. % to 33 wt. % of the at least one polypropylene elastomeric copolymer, and up to 20 wt. % of the at least one polymer selected from the group consisting of styrene-ethylene-co-butene-styrene triblock copolymers, styrene-ethylene-co-propylene-styrene triblock copolymers, styrene-ethylene-co-butene diblock copolymers, styrene-ethylene-co-propylene diblock copolymers and combinations thereof.

    20. The multilayer oriented shrink film of claim 17, wherein the at least one skin layer further comprises up to 20 wt. % of at least one other polymer comprising at least one of the following features: (a) the at least one other polymer comprises styrene in an amount of at least 40 wt. % of the at least one other polymer; and (b) the at least one other polymer is a member selected from the group consisting of styrene-ethylene-co-butene-styrene triblock copolymers, styrene-ethylene-co-propylene-styrene triblock copolymers, styrene-ethylene-co-butene diblock copolymers and styrene-ethylene-co-propylene diblock copolymers.

    21. The multilayer oriented shrink film of claim 20, comprising a second skin layer on a second side of said core layer opposite to said first side of said core layer, said skin layers on each side of said core layer being of the same composition.

    22. The multilayer oriented shrink film of claim 17, wherein said film has a density of less than 1 g/cm.sup.3, said film has a transverse direction shrink level in excess of 50% at 95° C., and a predominant film orientation is in a transverse direction or said film is uniaxially oriented in the transverse direction.

    23-28. (canceled)

    29. The multilayer oriented shrink film of claim 17, said at least one skin layer and the core layer being the sole layers in said film.

    30-31. (canceled)

    32. The multilayer oriented shrink film of claim 17, wherein said at least one skin layer comprises: 80 wt. %-99 wt. % of the amorphous styrene-butadiene block copolymer; and 1 wt. %-20 wt. % of a high styrene content polymer selected from the group consisting of styrene-ethylene-co-butene-styrene triblock copolymers, styrene-ethylene-co-propylene-styrene triblock copolymers, styrene-ethylene-co-butene diblock copolymers and styrene-ethylene-co-propylene diblock copolymers.

    33-42. (canceled)

    43. The multilayer oriented shrink film of claim 17, wherein the core layer further comprises at least one aliphatic, hydrogenated hydrocarbon resin.

    44. The multilayer oriented shrink film of claim 17, wherein said core layer comprises 1 to 12 wt. % of at least one aliphatic, hydrogenated hydrocarbon resin.

    45-54. (canceled)

    55. The multilayer oriented shrink film of claim 17, wherein the core layer further comprises a reclaim polymer, and optionally, a non-voiding opacifying agent and/or a voiding agent.

    56. The multilayer oriented shrink film of claim 55, wherein said core layer comprises: 20 wt. % to 35 wt. % of the polypropylene co- or terpolymer selected from the group consisting of polypropylene terpolymers with ethylene and butene-1, propylene ethylene copolymers, propylene butene-1 copolymers and combinations thereof 10 wt. % to 25 wt. % of the at least one polybutene-1 copolymer, 10 wt. % to 30 wt. % of the at least one polypropylene elastomeric copolymer, 10 wt. % to 60 wt. % of the reclaim polymer, and up to 10% of a polyethylene based TiO.sub.2 concentrate.

    57. The multilayer oriented shrink film of claim 55, wherein said at least one skin layer comprises: 80 wt. %-99 wt. % of the amorphous styrene-butadiene block copolymer, and 1 wt. %-20 wt. % of the at least one other polymer, which is a member selected from the group consisting of styrene-ethylene-co-butene-styrene triblock copolymers, styrene-ethylene-co-propylene-styrene triblock copolymers, styrene-ethylene-co-butene diblock copolymers and styrene-ethylene-co-propylene diblock copolymers.

    58. The multilayer oriented shrink film of claim 55, wherein the reclaim polymer is a member selected from the group consisting of terpolymer, butene-ethylene copolymer, propylene-based elastomer, styrene ethylene-co-butene-styrene block copolymer, styrene-butadiene block copolymer, and combinations thereof.

    59-68. (canceled)

    69. The multilayer oriented shrink film of claim 17, further comprising a second skin layer which is disposed on a second side of the core layer opposite from said first skin layer, wherein said second skin layer comprises at least one Cyclic Olefin Copolymer; wherein said core layer has a thickness greater than said first skin layer and second skin layer, and the film has a haze less than 6%.

    70. The multilayer oriented shrink film of claim 69, wherein said core layer comprises: 30 wt. % to 40 wt. % of the at least one polypropylene co- or terpolymer selected from the group consisting of polypropylene terpolymers with ethylene and butene-1, propylene ethylene copolymers, propylene butene-1 copolymers and combinations thereof, 20 wt. % to 27 wt. % of the at least one polybutene-1 copolymer, 20 wt. % to 33 wt. % of the at least one polypropylene elastomeric copolymer, up to 20 wt. % of the at least one polymer selected from the group consisting of styrene-ethylene-co-propylene-styrene-ethylene tetrablock, styrene-ethylene-co-butene-styrene triblock copolymers, styrene-ethylene-co-propylene-styrene triblock copolymers, styrene-ethylene-co-butene diblock copolymers and styrene-ethylene-co-propylene diblock copolymers and combinations thereof, and up to 12 wt. % of at least one aliphatic, hydrogenated hydrocarbon resin.

    71. The multilayer oriented shrink film of claim 69, wherein said first skin layer comprises: 80 wt. %-99 wt. % of the at least one amorphous styrene-butadiene block copolymer, and 1 wt. %-20 wt. % of a polymer selected from the group consisting of styrene-ethylene-co-butene-styrene triblock copolymers, styrene-ethylene-co-propylene-styrene triblock copolymers, styrene-ethylene-co-butene diblock copolymers and styrene-ethylene-co-propylene diblock copolymers.

    72-81. (canceled)

    82. The multilayer oriented shrink film of claim 17, further comprising: a first intermediate layer between said at least one skin layer and said core layer, said first intermediate layer comprising a blend of one or more polymers selected from the group consisting of styrene-ethylene-co-butene-styrene triblock copolymer, styrene-ethylene-co-propylene-styrene triblock copolymer, styrene-ethylene-co-butene diblock copolymer, styrene-ethylene-co-propylene diblock copolymer and at least one or more polypropylene terpolymer or copolymer; a second intermediate layer between a second skin layer and said core layer, said second intermediate layer comprising a blend of one or more polymers from the group consisting of styrene-ethylene-co-butene-styrene triblock copolymer, styrene-ethylene-co-propylene-styrene triblock copolymer, styrene-ethylene-co-butene diblock copolymer, styrene-ethylene-co-propylene diblock copolymer and at least one or more polypropylene terpolymer or copolymer; and the second skin layer which is disposed on the opposite side of the core layer from said first skin layer, wherein said second skin layer comprises at least 80 wt. % of at least one amorphous styrene-butadiene block copolymer, and 0 to 20 wt. % of at least one high styrene content polymer selected from the group consisting of styrene-ethylene-co-butene-styrene triblock copolymers, styrene-ethylene-co-propylene-styrene triblock copolymers, styrene-ethylene-co-butene diblock copolymers and styrene-ethylene-co-propylene diblock copolymers; wherein said core layer has a thickness greater than said first skin layer and second skin layer, and said film has a haze less than 6%.

    83. The multilayer oriented shrink film of claim 82, wherein said core layer comprises: 30 wt. % to 40 wt. % of the polypropylene co- or terpolymer selected from the group consisting of polypropylene terpolymers with ethylene and butene-1, propylene ethylene copolymers, propylene butene-1 copolymers and combinations thereof; 20 wt. % to 27 wt. % of the polybutene-1 copolymer; 20 wt. % to 33 wt. % of a polypropylene elastomeric copolymer; up to 20 wt. % of a polymer selected from the group consisting styrene-ethylene-co-propylene-styrene-ethylene-co-propylene tetrablock, styrene-ethylene-co-butene-styrene triblock copolymers, styrene-ethylene-co-propylene-styrene triblock copolymers, styrene-ethylene-co-butene diblock copolymers and styrene-ethylene-co-propylene diblock copolymers and combinations thereof; and up to 12 wt. % of an aliphatic, hydrogenated hydrocarbon resin; wherein said first skin layer comprises: 80 wt. %-99 wt. % of the amorphous styrene-butadiene block copolymer; and 1%-20% of the high styrene content polymers selected from the group consisting of styrene-ethylene-co-butene-styrene triblock copolymers, styrene-ethylene-co-propylene-styrene triblock copolymers, styrene-ethylene-co-butene diblock copolymers and styrene-ethylene-co-propylene diblock copolymers; wherein said first intermediate layer and said second intermediate layer comprise: 60 wt. %-95 wt. % of a blend of one or more polymers from the group consisting of styrene-ethylene-co-butene-styrene triblock copolymer, styrene-ethylene-co-propylene-styrene triblock copolymer, styrene-ethylene-co-butene diblock copolymer, styrene-ethylene-co-propylene diblock copolymer; and 5 wt. %-40 wt. % at least one or more polypropylene terpolymer or copolymer; wherein said second skin layer comprises: 80 wt. %-99 wt. % of the amorphous styrene-butadiene block copolymer; 1 wt. %-20 wt. % of the high styrene content polymers selected from the group consisting of styrene-ethylene-co-butene-styrene triblock copolymers, styrene-ethylene-co-propylene-styrene triblock copolymers, styrene-ethylene-co-butene diblock copolymers and styrene-ethylene-co-propylene diblock copolymers; and wherein said film has a density of less than 1 g/cm.sup.3, said film has a transverse direction shrink level in excess of 50% at 95° C., and a predominant film orientation is in a transverse direction or said film is uniaxially oriented in the transverse direction.

    84-94. (canceled)

    95. The multilayer oriented shrink film of claim 82, wherein said core layer comprises: 30 wt. % to 40 wt. % of the at least one polypropylene co- or terpolymer selected from the group consisting of polypropylene terpolymers with ethylene and butene-1, propylene ethylene copolymers, propylene butene-1 copolymers and combinations thereof; 20 wt. % to 27 wt. % of the at least one polybutene-1 copolymer; 20 wt. % to 33 wt. % of the at least one polypropylene elastomeric copolymer; 10% to 60% of a reclaim polymer; and 0% to 10% of a polyethylene based TiO.sub.2 concentrate, wherein said film has a density of less than 1 g/cm.sup.3, said film has a transverse direction shrink level in excess of 50% at 95° C., and a predominant film orientation is in a transverse direction or said film is uniaxially oriented in the transverse direction.

    96. The multilayer oriented shrink film of claim 95, wherein the reclaim polymer is a member selected from the group consisting of Terpolymer, butene-ethylene copolymer, propylene-based elastomer, styrene ethylene-co-butene-styrene block copolymer, styrene-butadiene block copolymer, and combinations thereof.

    97-106. (canceled)

    107. A method of making the multilayer oriented shrink film of claim 17.

    108. A process of seaming a multilayer oriented shrink film, the process comprising: providing the multilayer oriented shrink film of claim 17; forming a sleeve with said the multilayer oriented shrink film; providing a seaming solvent comprising: at least one terpene component; at least one ether component selected from the group consisting of a straight chain ether, a branched chain ether, a cyclic ether, a substituted cyclic ether, a cyclic diether, a substituted cyclic diether, and combinations thereof; and at least one ketone components selected from the group consisting of a straight chain ketone, a branched chain ketone, a cyclic ketone, a substituted cyclic ketone, and combinations thereof; and applying the seaming solvent, thereby forming a seam.

    109-111. (canceled)

    Description

    BRIEF DESCRIPTION OF THE DRAWINGS

    [0066] FIG. 1 is a graph showing transverse direction shrink profile with temperature;

    [0067] FIG. 2 is a graph showing transverse direction shrink at various temperatures in relation to film density;

    [0068] FIG. 3 is a graph showing flex and Gurley stiffness as a function of film thickness;

    [0069] FIG. 4 is a graph showing the UV-VIS Spectra of PS skin films;

    [0070] FIG. 5 is a graph showing the relationship between MD flex stiffness and film thickness for shrink films including polystyrene (PS) skins and commercial glycol modified polyethylene terephthalate (PETG) films; and

    [0071] FIG. 6 is a graph showing the relationship between MD flexes stiffness and film yield for shrink films including polystyrene (PS) skins and commercial glycol modified polyethylene terephthalate (PETG) films.

    DETAILED DESCRIPTION OF THE INVENTION

    [0072] The following describes a number of embodiments of this invention. One embodiment, identifying optional components in the core or base layer is depicted below.

    [0073] Corona Treatment (optional)

    TABLE-US-00001 ~4-12 μm - skin layer 65-100%  Styrolux S/0-35% Styrolux T SBC 32-45 μm - core layer 20-40% LYB Adsyl 6C30F Terpolymer 10-27% LYB Koattro DP8310M Polybutene-1 copolymer 10-33% Vistamaxx 3980FL  5-20% Kraton G SEPSEP or SEBS or SEP or SEPS Block Copolymers ~4-12 μm - skin layer 65-100%  Styrolux S/0-35% Styrolux T SBC

    [0074] Corona Treatment (optional)

    [0075] Polymers

    [0076] Styrene Polymers—Styrene-Butadiene-Styrene block copolymers are commercially available from Ineos Styrolution America, LLC, Aurora, Ill. or its distributor, PolyOne Corporation, Littleton, Mass. General purpose polystyrene homopolymers are commercially available from American Styrenics, The Woodlands, Tex. or its distributor PolyOne Corporation, Littleton, Mass. The following is a non-exclusive listing of exemplary styrene polymers that are, or that may be usable in the skin layers of the films of this invention:

    [0077] Styrolux S, Styrene-Butadiene-Styrene block copolymer (S/B/S) with a specific gravity of 1.02 g/cm.sup.3, an MFR (200/5)=10 dg/min and a Vicat softening temperature of 72° C.

    [0078] Styrolux T, styrene-butadiene block copolymer (SBC) with a specific gravity of 1.02 g/cm.sup.3, an MFR (200/5)=10 dg/min and a Vicat softening temperature of 67° C.

    [0079] K-resin KR-52, a styrene-butadiene block copolymer (SBC) with a specific gravity of 1.01 g/cm.sup.3, an MFR (200/5)=9 dg/min and a Vicat softening temperature of 61° C. It is also available from Ineos Styrolution America, and can be used in place of Styrolux T, in combination with Styrolux S and Styrolux T, or can be used alone.

    [0080] EA3400, is a general purpose polystyrene homopolymer with a specific gravity of 1.04 g/cm.sup.3, an MFR (200/5)=9 dg/min and a Vicat softening temperature of 99° C. This homopolymer is usable in combination with Styrolux T or K-resin KR-52 in the skin layer to provide a balance of stiffness and shrink performance. Preferably EA3400 is present in the range of from about 1% to about 70% by weight of the combination in the skin.

    [0081] Polypropylene Terpolymer and Copolymers—Polypropylene terpolymers are commercially available from LyondellBasell, Houston, Tex. under the trade name Adsyl. The following is a non-exclusive listing of exemplary polypropylene terpolymers that are, or that may be usable in the core layers of the films in this invention:

    [0082] LyondellBasell Adsyl 6C30F is a Ziegler-Natta catalyzed random terpolymers of propylene, ethylene, and butene with the propylene being the predominant component, by weight, of the terpolymer. Adsyl 6C30F has a MFR (230/2.16) of 5.5 dg/min, a SIT of 98° C., and a DSC peak melting point of 126° C.

    [0083] Adsyl 7410XCP also is a terpolymer of propylene, ethylene and butene, with propylene being the predominant component, by weight, and which has a MFR (230/2.16) of 5.5 dg/min, a SIT of 75° C., and a DSC peak melting point of 125° C. and Adsyl 5C30F with a melt flow rate of 5.5 dg/min (230° C., 2.16 kg), a SIT of 105° C., and a DSC peak melting point of 132° C.

    [0084] Polypropylene copolymers with ethylene or butene-1 as co-monomers are commercially available from a number of sources, including LyondellBasell in Houston, Tex., Ineos Olefins & Polymers USA headquartered in League City, Tex., Braskem America Inc. headquartered in Philadelphia, Pa., Mitsui Chemicals America in New York, N.Y., and Total USA headquartered in Houston, Tex. The following is a non-exclusive listing of exemplary polypropylene copolymers that are, or that may be usable in the core layers in the films of this invention:

    [0085] Ineos Eltex P KS407 is a copolymer of propylene and about 4.0% ethylene, with propylene being the predominant component, by weight, and which has a MFR (230/2.16) of 5 dg/min, and a DSC peak melting point of 134° C.

    [0086] Braskem DS6D82 is a copolymer of propylene and about 4.0% ethylene, with propylene being the predominant component, by weight, and which has a MFR (230/2.16) of 7 dg/min, and a DSC peak melting point of 134° C.

    [0087] Total 8573 is a copolymer of propylene and ethylene with propylene being the predominant component, by weight; having a MFR (230/2.16) of 6.8 dg/min and having a DSC peak melting point of approximately 135° C.

    [0088] LyondellBasell Adsyl 7416 XCP is a copolymer of propylene and ethylene with propylene being the predominant component, by weight; having a MFR (230/2.16) of 7.5 dg/min and having a DSC peak melting point of approximately 133° C.

    [0089] LyondellBasell Adsyl 7415 XCP is a copolymer of propylene and ethylene with propylene being the predominant component, by weight, having a MFR (230/2.16) of 0.9 dg/min and having a DSC peak melting point of approximately 133° C.

    [0090] LyondellBasell Adsyl 3C30F HP is a copolymer of propylene and butene-1 with the propylene being the predominant component, by weight, of the copolymer and which has a MFR (230/2.16) of 5.5 dg/min, and a DSC peak melting point of 137° C.

    [0091] Mitsui Chemicals Tafmer XM-7090 is a copolymer of propylene and butene-1 with the propylene being the predominant component, by weight, of the copolymer and which has a melt flow rate of 7.0 dg/min (230° C., 2.16 kg), and a DSC peak melting point of 98° C. Mitsui Chemicals Tafmer XM-7080 is a copolymer of propylene and butene-1 with the propylene being the predominant component, by weight, of the copolymer and which has a melt flow rate of 7.0 dg/min (230° C., 2.16 kg), and a DSC peak melting point of 83° C. Mitsui Chemicals Tafmer XM-7070 is a copolymer of propylene and butene-1 with the propylene being the predominant component, by weight, of the copolymer and which has a melt flow rate of 7.0 dg/min (230° C., 2.16 kg), and a DSC peak melting point of 75° C. These copolymers is available from Mitsui Chemicals America in New York, N.Y.

    [0092] Polypropylene terpolymers and copolymers are primary components of the core and provide high clarity and are a contributing factor to high shrink performance within the temperature range requirement of heat shrink label applications (90-100° C.). Reference to the polypropylene terpolymers and copolymers being the “primary component” means that the percentage by weight of these polymers combined is greater than the percentage, by weight of any of the other components in the core.

    [0093] Polybutene-1 Copolymer—Polybutene-1 copolymers are commercially available from LyondellBasell, Houston, Tex. under the trade names Koattro and Toppyl. LyondellBasell Koattro DP8310M and Toppyl DP8220M are Polybutene-1 copolymers with ethylene.

    [0094] Koattro DP8310M has a MFR (190/2.16) of 3.5 dg/min, a melting point of 94° C., and a density of 0.897 g/cc, and is characterized as having a high ethylene content. In this copolymer the ethylene content is less than 50% by weight thereof, and most preferably is less than 15% by weight.

    [0095] Toppyl DP8220M has a MFR (190/2.16) of 2.5 dg/min, a melting point of 97° C., and a density of 0.901 g/cc and is characterized as having a medium ethylene content. In this copolymer the ethylene content is less than 50 by weight, and most preferably is less than 15% by weight. This does have a lower ethylene content than Koattro DP8310M, identified above.

    [0096] Polybutene-1 copolymer is an important component of the core; constituting a major factor to high shrink performance within the temperature range requirement of heat shrink label applications (90-100° C.).

    [0097] Vistamaxx and Versify Copolymers—Propylene-based polyolefin elastomers (POE's) are commercially available from ExxonMobil Chemical Company under the trade name Vistamaxx or Dow Chemical Company under the trade name Versify.

    [0098] Composition and structure: These POE's are semi-crystalline copolymers of propylene and ethylene with high propylene levels (>80 wt. %) with isotactic stereochemistry. Crystallinity is modulated by the ethylene content to 5-45% crystallinity complementary to a large amorphous fraction. These POE's also have the following properties: a narrow Molecular Weight Distribution (MWD), a MFR (230/2.16) in the range of 2 to 25 g/10 min, a density in the range of 0.863 to 0.891 g/cm.sup.3, a Glass Transition Temperature Tg in the range of 5 to −31° F. (−15 to −35° C.) and a Melting Range: of 122 to 248° F. (50 to 120° C.) and higher.

    [0099] Vistamaxx 3980FL: MFR (190/2.16) of 3.2 dg/min, ethylene content of 9%, density of 0.879 g/cc, and Vicat softening point of 76.7° C.

    [0100] Versify 3000: MFR (230/2.16) of 8 dg/min, density of 0.88 g/cc, melting point of 108° C., crystallinity=44%, and Vicat softening point of 52° C.

    [0101] The propylene based POE, like the polybutene-1 copolymer, is an important component of the core layer; contributing to the desired, high shrink performance within the temperature range requirement for heat shrink label applications (90-100° C.).

    [0102] Styrene Block Copolymers (S-E/B-S and S-E/P)—Elastomeric Styrene block copolymers (SBC) with triblock styrene-ethylene-co-butene-styrene or styrene-ethylene-co-propylene-styrene or diblock styrene-ethylene-co-butene or styrene-ethylene-co-propylene structures which are used in the core layer of the films of this invention are commercially available from Kraton Corporation, Houston, Tex. or its distributor Univar Solutions, Downers Grove, Ill. Other Styrene block copolymers considered to be usable in this invention, and identified hereinafter, are commercially available from Kuraray Elastomer Division of Kuraray Americas, Inc., Houston, Tex. and Asahi Kasei, Tokyo, Japan, or its distributor Marubeni Specialty Chemicals Inc., White Plains, N.Y. The elastomeric styrene block copolymers are present in the core together with the Propylene-based elastomer. The core can include one or more elastomeric styrene block copolymers in which the “rubbery block” composition is ethylene-butene or ethylene-propylene. These elastomeric materials have a specific gravity in the range of 0.89 to 0.93 g.Math.cm.sup.3, a styrene content of 12 to 40%, and an ethylene-butene or ethylene-propylene copolymer content of 60-88%, by weight.

    [0103] Suitable Kraton elastomeric styrene block copolymers include:

    [0104] Kraton G1645: Styrene-ethylene-co-butene-Styrene triblock elastomer with 12.5% styrene content, MFR (230/2.16)=3.3 dg/min, and ethylene-co-butene block Tg=−42.

    [0105] Kraton G1652: Styrene-ethylene-co-butene-Styrene triblock elastomer with 30% styrene content, MFR (230/2.16)=5 dg/min, and a specific gravity of 0.91 g/cm.sup.3.

    [0106] Kraton G1643: Styrene-ethylene-co-butene-Styrene triblock elastomer with 20% styrene content, MFR (230/2.16)=19 dg/min, and a specific gravity of 0.90.

    [0107] Kraton G1657: Styrene-ethylene-co-butene-Styrene triblock (70%)/Styrene-ethylene-co-butene diblock (30%) with 13% styrene content, MFR (230/5)=22, and a specific gravity of 0.90 g/cm.sup.3.

    [0108] Kraton G1726: Styrene-ethylene-co-butene-Styrene triblock (30%)/Styrene-ethylene-co-butene diblock (70%) with 30% styrene content, MFR (190/2.16)=19, and a specific gravity of 0.91 g/cm.sup.3.

    [0109] Kraton G1730: Styrene-ethylene-co-propylene-styrene-ethylene-co-propylene tetrablock elastomer with 21% styrene content, MFR (230/5)=13 dg/min, and a specific gravity of 0.90 g/cm.sup.3.

    [0110] Kraton G1701: Styrene-ethylene-co-propylene diblock elastomer with 37% styrene content, MFR (230/5)=1 dg/min, and a specific gravity of 0.92 g/cm.sup.3.

    [0111] Kraton G1702: Styrene-ethylene-co-propylene diblock elastomer with 28% styrene content, MFR (230/5)<1 dg/min, and a specific gravity of 0.91 g/cm.sup.3.

    [0112] Elastomeric Styrene block copolymers (SBC) are also available from Kuraray Elastomer Division of Kuraray Americas, Inc., Houston, Tex. under the tradename SEPTON. Suitable SEPTON elastomer grades would include:

    [0113] SEPTON 2063: Styrene—ethylene-co-propylene-Styrene triblock elastomer with 13% styrene content, MFR (230/2.16)=7 dg/min.

    [0114] SEPTON 2004F: Styrene—ethylene-co-propylene-Styrene triblock elastomer with 18% styrene content, MFR (230/2.16)=5 dg/min SEPTON 2002: Styrene—ethylene-co-propylene-Styrene triblock elastomer with 30% styrene content, MFR (230/2.16)=70 dg/min.

    [0115] Elastomeric Styrene block copolymers (SBC) are also available from Asahi Kasei, Tokyo, Japan or its distributor Marubeni Specialty Chemicals Inc., White Plains, N.Y. under the tradename Tuftec.

    [0116] Tuftec P1500 SEBS with a specific gravity=0.91 g/cm.sup.3, a PS content=30%, and a MFR (190/2.16)=4.0.

    [0117] Processing

    [0118] Manufacturing of the multilayer oriented shrink film according to this invention can be carried out on a typical tenter frame BOPP line, however, it requires process conditions that are different from those used for making other BOPP label or packaging films. So the cast film is much thinner and sensitive to the exact width of the die lip gap, MD orientation is minimal (less than 1.4× at 80-90° C.), and TD orientation is fairly cold (7× to 8.5× at 90-105° C.). The essentially uniaxial TD-only oriented film is then wound up on a bobbin.

    [0119] Manufacturing MD shrink films in accordance with this invention can be carried out in a manner known to those skilled in the art. For example, a multi-layer, relatively thick cast film is co-extruded through a flat film die. The cast film is then quenched or cooled on a chill roll or series of stacked casting rolls. The cooled cast film then is directed into a MD orientation unit where it traverses a series of heated rolls. The reheated cast film is then stretched or oriented up to 10 times or more on smaller diameter rolls rotating at progressively higher speeds. The essentially uniaxially, MD only oriented film is then wound up on a bobbin.

    EXAMPLES

    [0120] In a first embodiment (Examples 1-5) three layer shrink films include opposed skin layers comprising one or more styrene-butadiene block copolymers and a core layer. The core layer optionally includes one or more styrene-ethylene-co-propylene-styrene-ethylene-co-propylene tetrablock, styrene-ethylene-co-butene-styrene or styrene-ethylene-co-propylene-styrene triblock or styrene-ethylene-co-butene or styrene-ethylene-co-propylene diblock copolymers or combinations therein, in combination with a propylene-ethylene-butene terpolymer, a butene-ethylene copolymer and a propylene-based elastomeric polymer. A representative film structure illustrating this embodiment is shown below:

    [0121] Corona Treatment (optional)

    TABLE-US-00002 ~4-12 μm skin layer 60-100%  Styrolux S  0-40% Styrolux T 32-45 um core layer 36-40% LYB Adsyl 6C30F Terpolymer 20-27% LYB Koattro DP8310M Polybutene-1 copolymer 20-33% Vistamaxx 3980FL or Versify 3000 SEB  0-20% Kraton G SEPSEP or SEBS or SEPS or SEP or Block Copolymers ~4-12 μm skin layer 60-100%  Styrolux S  0-40% Styrolux T

    [0122] Corona Treatment (optional)

    Example 1

    [0123] A three layer film, identified as Example 1, comprising a core layer and opposed skin layers contiguous with the opposite faces of the core layer was coextruded, cast on a sequence of two chill rolls at 40° C., stretched in machine direction (MD) 1.2× at 80° C., then stretched in a tenter frame at 95° C., cooled and wound up as described above. The exact formulation and physical properties are summarized in Tables 1 and 2. The core layer included Adsyl 6C30F C.sub.3C.sub.2C.sub.4 terpolymer in combination with Koattro DP8310M C.sub.4C.sub.2 copolymer, Vistamaxx 3980FL C.sub.3C.sub.2 copolymer, and Kraton G1645 styrene-ethylene-co-butene-styrene triblock copolymer. Both skin layers included a blend of Styrolux S and Styrolux T styrene-butadiene block copolymers.

    TABLE-US-00003 TABLE 1 Example 1. Three Layer Unit of Symmetrical Film Styrolux Film Property Measure S/Styrolux T Skins Skin Composition 65% Styrolux S/35% Styrolux T Core Composition 36% Adsyl 6C30F/24% Koattro DP8310M/20% Vistamaxx 3980FL/ 20% Kraton G1645 Yield in.sup.2/lb 14,193 Density g/cm 0.916 Film Thickness microns 54 (calculated) Skin Thickness microns 7.3 (measured) Haze % 4.3 Blocking RT, 150 psi, 24 hrs No Blocking 35° C., 150 psi, No Blocking 3 hrs Gurley Stiffness 11.9/18.8 MD/TD Flex Stiffness g/in 3.6/4.2 MD/TD COF In/In 0.56/0.54 Out/Out 0.51/0.46 In/Out 0.48/0.47

    [0124] The three layer structure of Example 1 with skins consisting of a blend of two styrene block copolymers (Styrolux T and Styrolux S) provides an attractive balance of optical properties, floatability, stiffness, and the absence of blocking under typical storage conditions. TD shrink performance of this three layer structure is also very good with shrink initiation slightly above 60° C. and shrink levels above 50% at temperatures at or above 90° C., as illustrated in Table 2 below.

    TABLE-US-00004 TABLE 2 Example 1. Three Layer Unit of Symmetrical Film Styrolux Film Property Measure S/Styrolux T Skins Skin Composition 65% Styrolux S/35% Styrolux T Core Composition 36% Adsyl 6C30F/24% Koattro DP8310M/ 20% Vistamaxx 3980FL/20% Kraton G1645 TD Shrink 60° C. % 0 65° C. % 5 70° C. % 16 75° C. % 28 80° C. % 36 85° C. % 45 90° C. % 51 95° C. % 59 100° C.  % 64 105° C.  % 67

    Example 2

    [0125] Additional three layer structures having varying skin and film thickness were fabricated by coextrusion, cast on a sequence of two chill rolls at 40° C., stretched in machine direction (MD) 1.2× at 80° C., then stretched in a tenter frame at 95° C., cooled and wound up as described above. The three layer structures each including two component styrene block copolymer symmetrical skins and a four component elastomeric core. These latter structures (6 in number), as a group, are identified as Example 2, and the composition and properties of these six structures are described in greater detail in Table 3 below.

    TABLE-US-00005 TABLE 3 Film Unit of Example 2. Three Layer Symmetrical Styrolux Property Measure S/Styrolux T Skins Skin 65% Styrolux S/35% Styrolux T Composition Core 36% Adsyl 6C30F/24% Koattro DP8310M/ Composition 20% Vistamaxx 3980FL/20% Kraton G1645 Yield in.sup.2/lb 16,866 16,249 14,949 13,206 12,735 12,155 Density g/cm.sup.3 0.944 0.924 0.924 0.935 0.927 0.940 Film microns 44 47 51 57 59 61 Thickness (calculated) Skin microns 6.4 5.8 8.8 9.9 7.9 9.8 Thickness (measured) Haze % 1.9 2.1 3.0 3.1 2.8 2.5 45° Gloss-IN gu >100 >100 >100 >100 >100 >100 45° Gloss- gu >100 >100 >100 >100 >100 >100 OUT Blocking RT, 150 g/in No blocking psi, 24 hrs 35° C., 150 g/in No blocking psi, 3 hrs Gurley 4.3/— 4.6/5.8 8.1/8.0 12.3/12.7 906/10.1 11.3/18.2 Stiffness MD/TD Flex Stiffness g/in 1.8/2.3 2.4/2.8 3.0/3.7 4.8/5.5 4.5/5.5 5.7/6.8 MD/TD PIN Puncture g — — — 1356 — 1283 COF In/In — — — 0.52/0.49 — 0.51/0.49 Out/Out — — — 0.51/0.49 — 0.53/0.50 In/Out — — — 0.49/0.46 — 0.50/0.50

    [0126] The six structures of Example 2 also possessed a very attractive balance of optical properties, floatability, and stiffness with the absence of blocking under typical storage conditions. Despite the almost uniaxial nature of orientation in these films of Example 2 (MD=1.2×, TD=7.4×) the stiffness performance of the films in both directions was surprisingly well balanced in both Gurley and Flex Stiffness tests. As expected, the stiffness of the film was determined to be a strong function of overall film thickness.

    [0127] As illustrated in Table 4 below, a very consistent and predictable shrink performance also was obtained in Example 2, independent of overall thickness or skin thickness of the film. Specifically the TD shrink level was in the low to mid 60% range in the 90° C. to 95° C. temperature range for all of the six films. The films of Example 2 all had a very moderate Shrink Tension force, and meaningful TD shrink initiation occurred at a temperature above 60° C.

    TABLE-US-00006 TABLE 4 Film Unit of Example 2. Three Layer Symmetrical Property Measure Styrolux S/Styrolux T Skins Skin 65% Styrolux S/35% Styrolux T Composition Core 36% Adsyl 6C30F/24% Koattro DP8310M/ Composition 20% Vistamaxx 3980FL/20% Kraton G1645 TD Shrink  60° C. % 1 2 1 1 1 1  65° C. % 10 11 10 10 10 10  70° C. % 21 23 23 23 23 22  75° C. % 34 33 36 36 36 34  80° C. % 43 43 44 45 46 44  85° C. % 51 51 51 52 52 52  90° C. % 60 59 58 58 60 60  95° C. % 62 63 62 64 64 63 100° C. % 67 68 67 68 68 68 105° C. % 71 70 70 71 71 71 Shrink Tension TD  80° C. grams — — — — 246 360  85° C. grams — — — — 287 354  90° C. grams — — — — 272 338  95° C. grams — — — — 285 346 100° C. grams — — — — 297 377 Natural Shrink MD/TD 30° C. % −0.5/0.0 — — −0.5/0.0 — −0.5/0.0 35° C. % −0.5/1.0 — — −0.3/0.8 — −0.5/0.8 40° C. % −0.5/4.0 — — −0.5/4.0 — −0.3/3.8 45° C. % −0.5/7.7 — —  0.0/7.5 —  0.0/7.1

    [0128] A comparison of the TD shrink profiles of a film with polystyrene skins (designated PS TDS), a film with PETG skins (designated PETG TDS) and a film with COC skins (designated COC TDS) is shown in FIG. 1. The values for the film with COC skins are average values from samples of multiple rolls of commercial film. The values for films with PETG skins and polystyrene skins are from a single sample of each film that was considered to reasonably represent the behavior of that film.

    [0129] As can be observed in FIG. 1, the film with polystyrene skins in accordance with this invention had the earliest shrink initiation point and a more moderate (i.e., gradual) temperature response as compared to the COC and PETG based film. As can be seen in FIG. 1, at the target shrink temperature of 95° C. for sleeve applications, all three floatable options deliver shrink levels in the low to mid 60's percent range; which is very desirable. A moderate temperature response and moderate shrink tensions observed is highly desirable in many shrink film applications as it provides better control over the labeling process, a higher quality result, and reduced tendency to collapse containers with thin walls.

    [0130] As presently determined, TD shrink performance (extent of shrink and the shape of the curve) of the films of this invention is essentially independent of film thickness or ratio of skin thickness to core thickness. This is illustrated in the composite view of film properties evaluated to date with skin composition ratio of 65% Styrolux S and 35% Styrolux T, as shown in the graph of FIG. 2, with the increasing density representing the increasing percentage the skin layer thickness of the total film thickness.

    [0131] It has been determined that the stiffness properties of the various films of this invention are primarily a function of the overall film thickness, as illustrated in the graph of FIG. 3.

    Example 3

    [0132] Six additional films, identified as Example 3 as a group, were fabricated by coextrusion, cast on a sequence of two chill rolls at 40° C., stretched in machine direction (MD) 1.2× at 80° C., then stretched in a tenter frame at 95° C., cooled and wound up as described above; including the same two components in the skins and the same four components in the core as the various Example 2 structures. However, these additional six structures differed from the Example 2 structures in that the ratio of the two component Styrene block copolymer skins was adjusted to a 3:1 ratio of Styrolux S/Styrolux T. These six additional films differed from each other in overall film thickness and skin thicknesses; the composition and physical properties being reported in Table 5 below.

    TABLE-US-00007 TABLE 5 Film Unit of Example 3. Three Layer 75% Styrolux S/25% Property Measure Styrolux T Skins Skin 75% Styrolux S/25% Styrolux T Composition Core 36% Adsyl 6C30F/24% Koattro DP8310M/20% Composition Vistamaxx 3980FL/20% Kraton G1645 Yield in.sup.2/lb 19,211 18,682 14,187 13,190 12,003 11,850 Density g/cm.sup.3 0.929 0.930 0.924 0.932 0.930 0.926 Film Thickness microns 39 40 54 57 63 64 (calculated) Skin Thickness microns 4.9 7.0 6.4 9.3 10.6 8.8 (measured) Blocking RT, 150 psi, g/in No blocking 24 hrs 35° C., 150 g/in No blocking psi, 3 hrs Gurley 3.0/3.7 3.5/4.3 7.8/9.6 9.6/12.0 —/20.1 15.6/16.8 Stiffness MD/TD Flex Stiffness g/in 1.5/1.9 1.6/2.0 3.3/3.9 4.4/5.5 7.1/8.5 5.9/7.5 MD/TD PIN Puncture g — — — 1,273 1,079 — COF Static/Kinetic In/In — — 0.52/0.49 0.51/0.49 — — Out/Out — — 0.51/0.49 0.53/0.50 — — In/Out — — 0.49/0.46 0.50/0.50 — —

    [0133] The six structures of Example 3 also possessed a very attractive balance of floatability and stiffness with the absence of blocking under typical storage conditions. Once again, despite the almost uniaxial nature of orientation in these films of Example 3, the stiffness performance of the films in both directions was surprisingly well balanced in both Gurley and Flex Stiffness tests. As expected, the stiffness of the film was determined to be a strong function of overall film thickness.

    [0134] Table 6 reports the results of percent shrinkage, shrink tension in the transverse direction and natural shrink in both the machine and transverse directions for the six Example 3 samples.

    TABLE-US-00008 TABLE 6 Film Unit of Example 3. Three Layer 75% Styrolux S/25% Property Measure Styrolux T Skins Skin 75% Styrolux S/25% Styrolux T Composition Core 36% Adsyl 6C30F/24% Koattro DP8310M/ Composition 20% Vistamaxx 3980FL/20% Kraton G1645 TD Shrink  60° C. % 2 1.5 1 0 0 1  65° C. % 11 10 11 9 10 10  70° C. % 24 22 24 22 24 25  75° C. % 35 35 39 38 39 39  80° C. % 44 45 46 47 49 49  85° C. % 51 52 52 52 54 53  90° C. % 59 58 60 59 60 60  95° C. % 63 64 65 63 64 64 100° C. % 67 68 68 67 68 68 105° C. % 70 71 71 70 71 71 Shrink Tension TD  80° C. grams — — 342 337 — —  85° C. grams — — 374 371 — —  90° C. grams — — 373 354 — —  95° C. grams — — 370 371 — — 100° C. grams — — 350 363 — — Natural Shrink MD/TD 30° C. % — −0.5/0.0 — −0.50/0.0  −0.50/0.0 — 35° C. % — −0.5/0.75 — −0.50/0.75 −0.50/0.5 — 40° C. % — −0.50/3.5 — −0.50/3.5 −0.50/3.5 — 45° C. % —  0.0/8.0 —  0.0/8.0   0.0/8.3 —

    [0135] As noted in Tables 6 and 4, a slightly higher average shrink tension was observed in the Example 3 films of this invention (Table 6) as compared to the Example 2 films of this invention. (Table 4). All other properties of the Example 3 films appear to be comparable to the Example 2 films. (See properties reported in Tables 5 and 6 for the Example 3 films, as compared to the properties reported in Tables 3 and 4 for the Example 2 films).

    Example 4

    [0136] Four additional films, identified as example 4 as a group, were fabricated by coextrusion, cast on a sequence of two chill rolls at 35° C., stretched in machine direction (MD) 1.2× at 85° C., then stretched in a tenter frame at 104° C., cooled and wound up as described above. The four films all contained Styrolux S to Styrolux T in the same four to one ratio in the skins with a core composition varying only in the styrene-ethylene-butene-styrene triblock copolymer or styrene-ethylene-butene diblock copolymer component. Properties are provided in Table 7 below.

    TABLE-US-00009 TABLE 7 Unit of Example 4. Three Eayer Styrolux Film Property Measure S/Styrolux T Skins Skin 80% Styrolux S/20% Styrolux T Composition Core 36% Adsyl 6C30F/24% Koattro DP8310M/ Composition 20% Vistamaxx 3980FT/20% Kraton GXXXX Kraton G Type G1645 G1643 G1726 G1657 in core Yield in.sup.2/lb 15,311 15,626 13,420 13,466 Density g/cm.sup.3 0.932 0.935 0.935 0.933 Film Thickness microns 50 48 55 56 (calculated) Skin Thickness microns 8.9 8.8 9.7 9.7 (measured) Haze % 1.0 1.1 0.9 0.9 Gloss-TN gu >100 >100 >100 >100 Gloss-OUT gu >100 >100 >100 >100 Blocking RT, 150 psi, 24 g/in No blocking hrs 35° C., 150 psi, g/in No blocking 3 hrs Gurley Stiffness 8.1/9.8 8.7/9.1 11.4/15.3 12.3/14.0 MD/TD Flex Stiffness g/in 3.4/4.2 3.3/3.7 5.1/6.0 5.7/6.7 MD/TD PIN Puncture g 1263 1387 1423 1278 COF Static/Kinetic 0.81/0.71 0.86/0.70 0.75/0.68 0.78/0.67 In/In 0.73/0.67 0.65/0.60 0.69/0.65 0.63/0.61 Out/Out 0.80/0.74 0.72/0.62 0.74/0.71 0.67/0.63 In/Out TD Shrink 60° C. % 3 2 2 3 65° C. % 11 10 8 11 70° C. % 23 21 19 22 75° C. % 35 32 30 34 80° C. % 46 42 40 45 85° C. % 53 51 51 54 90° C. % 61 59 59 60 95° C. % 66 64 64 65 100° C.  % 71 70 68 69 105° C.  % 74 72 72 71 Shrink Tension TD 80° C. grams 338 340 370 404 85° C. grams 347 334 385 441 90° C. grams 367 360 426 474 95° C. grams 384 383 411 467 100° C.  grams 378 371 392 429 Natural Shrink TD 30° C. % 0.5 0.5 0.5 0.8 35° C. % 1.3 1.0 1.0 1.5 40° C. % 4.5 4.0 3.5 5.0 45° C. % 8.0 7.0 6.5 8.3

    [0137] Optical properties (haze and gloss) are exceptional with the introduction of all four amorphous styrene block copolymers into the core. TD directional shrink of greater than 60% at 95° C. was also achieved in all films.

    Example 5

    [0138] Six additional films, identified as example 5 as a group, were fabricated by coextrusion, cast on a sequence of two chill rolls at 35° C., stretched in machine direction (MD) 1.1× at 85° C., then stretched in a tenter frame at 105° C., cooled and wound up as described above. The films all contained skin layers with 100% Styrolux S and a core composition containing Kraton G1645 styrene-ethylene-butene-styrene triblock copolymer at a level of 20 wt. %. The films vary only in the overall film thickness and smaller variations in the skin thickness. Properties are provided in Tables 8 and Table 9 below. Once again, excellent optical properties are observed. The use of Styrolux S as the sole component of the skin shifts the TD shrink initiation temperature to a higher temperature and also improves (raises) the natural shrink stability of the film.

    TABLE-US-00010 TABLE 8 Film Unit of Property Measure Example 5. Three Layer 100% Styrolux S Skins Skin Composition 100% Styrolux S Core Composition 36% Adsyl 6C30F/24% Koattro DP8310M/20% Vistamaxx 3980FL/20% Kraton G1645 Yield in.sup.2/lb 15,566 14,621 14,426 13,900 13,475 13,619 Density g/cm.sup.3 0.952 0.951 0.943 0.951 0.943 0.946 Film Thickness microns 48 51 52 53 55 55 (calculated) Skin Thickness microns 9.6 10.2 9.0 8.9 10.2 12.1 (measured) Haze % 1.6 — 1.2 2.0 1.5 — 45° Gloss-IN gu >100 — >100 >100 >100 — 45° Gloss-OUT gu >100 — >100 >100 >100 — Blocking RT, 150 psi, 24 hrs g/in No blocking 35° C., 150 psi, 3 hrs g/in No blocking Gurley Stiffness 8.2/10.0 —/— 10.0/13.2 —/— 13.7/14.2 14.2/16.2 MD/TD Flex Stiffness g/in 3.8/4.5 4.9/5.4 4.3/4.9 5.4/5.5 6.0/6.6 5.7/6.9 MD/TD PIN Puncture g 965 — 998 933 926 — COF Static/Kinetic In/In 0.81/0.73 — — 0.71/0.56 0.72/0.61 — Out/Out 0.61/0.60 — — 0.56/0.51 0.58/0.52 — In/Out 0.73/0.64 — — 0.61/0.56 0.63/0.61 —

    TABLE-US-00011 TABLE 9 Film Property Unit of Measure Example 5. Three Layer 100% Styrolux S Skins Skin Composition 100% Styrolux S Core 36% Adsyl 6C30F/24% Koattro DP8310M/ Composition 20% Vistamaxx 3980FL/20% Kraton G1645 TD Shrink  60° C. % −0.8 −0.7 −0.8 −0.8 −1 −0.5  65° C. % 0.7 0.3 0 1 1 1.0  70° C. % 12 11 11 13 12 12  75° C. % 30 28 28 30 29 29  80° C. % 43 41 41 44 42 43  85° C. % 52 50 50 54 52 51  90° C. % 59 57 57 61 58 59  95° C. % 66 63 62 65 64 63 100° C. % 70 70 68 70 70 68 105° C. % 74 73 71 74 73 72 Shrink Tension TD  80° C. grams 312 — 333 350 356 —  85° C. grams 278 — 308 371 360 —  90° C. grams 327 — 323 390 380 —  95° C. grams 287 — 312 371 377 — 100° C. grams 294 — 323 360 381 — Natural Shrink TD 30° C. % 0.0 0.0 0.0 0.0 0.0 0.0 35° C. % 0.0 0.0 0.0 0.0 0.0 0.0 40° C. % 1.5 1.5 1.5 1.5 1.5 1.5 45° C. % 1.5 1.5 1.5 1.5 1.5 1.5

    [0139] In a second embodiment of the present invention, a three layer shrink film includes a core layer and opposed skin layer having a thickness less than the core layer. Each of the skin layers includes one or more styrene-butadiene block copolymers and one or more styrene block copolymers from the group consisting of styrene-ethylene-co-butene-styrene triblock copolymers, styrene-ethylene-co-propylene-styrene triblock copolymers, styrene-ethylene-co-butene diblock copolymers and styrene-ethylene-co-propylene diblock copolymers The core layer optionally includes one or more styrene tetrablock, triblock or diblock copolymers therein, in combination with a propylene-ethylene-butene terpolymer, a butene-ethylene copolymer and a propylene-based elastomeric polymer. A representative film structure illustrating this embodiment is shown below.

    [0140] Corona Treatment (optional)

    TABLE-US-00012 ~4-12 μm skin layer 80-99% Styrolux S  1-20% SEBS or SEP or SEPS 32-45 μm core layer 36-40% 20-27% LYB Adsyl 6C30F Terpolymer copolymer 20-33% Vistamaxx 3980FL or Versify 3000  0-20% Kraton G SEPSEP or SEBS or SEPS or SEP or SEB Block Copolymers ~4-12 μm skin layer 80-99% Styrolux S  1-20% SEBS or SEP or SEPS

    [0141] Corona Treatment (optional)

    [0142] The composition of the various polymers in the above structure was provided earlier in this application.

    [0143] Triblock styrene-ethylene-co-butene-styrene or styrene-ethylene-co-propylene-styrene or diblock styrene-ethylene-co-butene or styrene-ethylene-co-propylene structures suitable to incorporate into the skin layer of this structure and are commercially available from Asahi KASEI Corporation, Tokyo, Japan and its distributor Marubeni Specialty Chemicals Inc., White Plains, N.Y. or Kraton Corporation, Houston, Tex. and its distributor Univar Solutions, Downers Grove, Ill. These styrene block copolymers include:

    [0144] Tuftec P2000 SEBS with a specific gravity=0.98 g/cm.sup.3, a PS content=67%, and a MFR (190/2.16)=3.0

    [0145] Tuftec P5051 SEBS with a specific gravity=0.94 g/cm.sup.3, a PS content=47%, and a MFR (190/2.16)=3.0

    [0146] S.O.E S1606 with a specific gravity=0.96 g/cm.sup.3, a MFR (230/2.16)=4.0, and a Shore A Hardness=67

    [0147] S.O.E S1611 with a specific gravity=1.02 g/cm.sup.3, a MFR (190/2.16)=4.0, and a Shore A Hardness=71

    [0148] S.O.E S1605 with a specific gravity=1.0 g/cm.sup.3, a MFR (230/2.16)=5.0, and a Shore A Hardness=87

    [0149] Kraton G1726: Styrene-ethylene-co-butene-Styrene triblock (30%)/Styrene-ethylene-co-butene diblock (70%) with 30% styrene content, melt flow rate=19 (190° C., 2.16 kg), and a specific gravity of 0.91 g/cm.sup.3.

    [0150] Tuftec P1500 SEBS with a specific gravity=0.91 g/cm.sup.3, a PS content=30%, and a MFR=4.0 (190 C, 2.16 kg).

    Example 6

    [0151] Three additional films, identified as example 6 as a group, were produced by coextrusion, cast on a sequence of two chill rolls at 35° C., stretched in machine direction (MD) 1.2× at 85° C., then stretched in a tenter frame at 103° C., cooled and wound up as described above. The films all contained skin layers with 80% Styrolux S in combination with Tuftec P5051 styrene-ethylene-co-butene-styrene triblock copolymer. The films vary only in the overall film thickness and smaller variations in the skin thickness. Properties are provided in tables 10 and table 11 below.

    TABLE-US-00013 TABLE 10 Unit of Example 6. Three Eayer Styrolux Film Property Measure S/Tuftec P5051 Skins Skin Composition 80% Styrolux S/20% Tuftec P5051 Core Composition 40% Adsyl 6C30F/27% Koattro DP8310M/33% Vistamaxx 3980FT Yield in.sup.2/lb 13,915 13,809 13,463 Density g/cm 0.927 0.930 0.927 Film Thickness microns 54 55 56 (calculated) Skin Thickness microns 8.3 8.0 6.8 (measured) Haze % 2.5 2.5 2.7 Gloss-TN gu >100 >100 >100 Gloss-OUT gu >100 >100 >100 Gurley Stiffness 9.0/9.7 11.6/11.4 10.2/10.6 MD/TD Flex Stiffness g/in 2.8/5.1 3.9/4.9 4.4/5.1 MD/TD PIN Puncture g 1298 1365 1426

    TABLE-US-00014 TABLE 11 Unit of Example 6. Three Layer Styrolux Film Property Measure S/Tuftec P5051 Skins Skin Composition 80% Styrolux S/20% Tuftec P5051 Core Composition 40% Adsyl 6C30F/27% Koattro DP8310M/33% Vistamaxx 3980FL TD Shrink 60° C. % −0.5 0.5 −1 65° C. % 1.2 1.2 1 70° C. % 10 11 12 75° C. % 24 25 24 80° C. % 37 38 37 85° C. % 46 47 47 90° C. % 52 54 55 95° C. % 60 61 61 100° C.  % 65 67 67 105° C.  % 69 70 71 Shrink Tension TD 80° C. grams 378 394 390 85° C. grams 400 379 372 90° C. grams 412 406 444 95° C. grams 423 390 408 100° C.  grams 412 418 418 Natural Shrink TD 30° C. % −0.3 −0.3 −0.3 35° C. % 0 0 0 40° C. % 1.3 1.3 1.3 45° C. % 3.0 3.3 3.0

    [0152] The three structures of Example 6 also possessed a very attractive balance of properties with the absence of blocking and low natural shrinks under typical storage conditions.

    Example 7

    [0153] Three additional films, identified as example 7 as a group, were produced by coextrusion, cast on a sequence of two chill rolls at 35° C., stretched in machine direction (MD) 1.2× at 85° C., then stretched in a tenter frame at 109° C., cooled and wound up as described above. The films all contained skin layers with 80% Styrolux S in combination with Tuftec P2000 styrene-ethyl ene-co-butene-styrene triblock copolymer. The films vary only in the overall film thickness and smaller variations in the skin thickness. Properties are provided in tables 12 and table 13 below.

    TABLE-US-00015 TABLE 12 Unit of Example 7. Three Layer Styrolux Film Property Measure S/Tuftec P2000 Skins Skin Composition 80% Styrolux S/20% Tuftec P2000 Core Composition 40% Adsyl 6C30F/27% Koattro DP8310M/33% Vistamaxx 3980FL Yield in.sup.2/lb 17,686 16,014 13,040 Density g/cm.sup.3 0.931 0.934 0.931 Film Thickness microns 43 47 58 (calculated) Skin Thickness microns 6.6 8.9 11.1 (measured) Haze % 1.6 1.7 1.9 Gloss-IN gu >100 >100 >100 Gloss-OUT gu >100 >100 >100 Gurley Stiffness 4.3/6.4 7.2/7.4 12.1/14.7 MD/TD Flex Stiffness g/in 2.2/2.7 3.1/3.7 5.9/6.6 MD/TD PIN Puncture g 1072 1070 1179

    TABLE-US-00016 TABLE 13 Unit of Example 7. Three Layer Styrolux Film Property Measure S/Tuftec P2000 Skins Skin Composition 80% Styrolux S/20% Tuftec P2000 Core Composition 40% Adsyl 6C30F/27% Koattro DP8310M/33% Vistamaxx 3980FL TD Shrink 60° C. % −0.5 −0.5 −0.5 65° C. % 0 0 0 70° C. % 7 7 6 75° C. % 19 17 18 80° C. % 33 34 33 85° C. % 42 40 41 90° C. % 50 49 50 95° C. % 59 58 58 100° C.  % 66 65 66 105° C.  % 71 71 70 Shrink Tension TD 80° C. grams 221 195 222 85° C. grams 240 263 295 90° C. grams 239 303 339 95° C. grams 214 269 293 100° C.  grams 258 246 323 Natural Shrink TD 30° C. % −0.3 −0.3 −0.3 35° C. % −0.3 −0.3 −0.3 40° C. % 0.8 0.8 0.8 45° C. % 2.3 2 1.8

    [0154] The three structures of Example 7 demonstrated further improvements in stability (lowered natural shrinks) under typical storage conditions can be achieved by raising the styrene content of the SEBS component of the skin. Exceptional optical properties were achieved with this skin structure.

    Example 8

    [0155] Three additional films, identified as example 8 as a group, were produced by coextrusion, cast on a sequence of two chill rolls at ° C., stretched in machine direction (MD) 1.2× at ° C., then stretched in a tenter frame at ° C., cooled and wound up as described above. The films all contained skin layers with 90% Styrolux S in combination with Kraton G1726 styrene-ethylene-co-butene diblock copolymer and a core composition also incorporating Kraton G1726 at a level of 20 wt. %. The films vary only in the overall film thickness and smaller variations in the skin thickness. Properties are provided in tables 14 and table 15 below.

    TABLE-US-00017 TABLE 14 Unit of Example 8. Three Layer Styrolux Film Property Measure S/Kraton G1726 Skins Skin Composition 90% Styrolux S/10% Kraton G1726 Core Composition 36% Adsyl 6C30F/24% Koattro DP8310M/20% Vistamaxx 3980FT/ 20% Kraton G1726 Yield in.sup.2/lb 14,860 Density g/cm 0.934 0.937 0.935 Film Thickness microns 51 58 60 (calculated) Skin Thickness microns 9.4 10.8 10.6 (measured) Haze % 6.3 6.6 6.8 Gloss-TN gu 87 87 86 Gloss-OUT gu 87 89 88 Blocking RT, 150 psi, 24 hrs g/in No blocking 35° C., 150 psi, g/in No blocking 3 hrs Gurley Stiffness 9.6/13.4 MD/TD Flex Stiffness g/in 4.3/5.1 6.1/7.2 6.7/7.7 MD/TD PIN Puncture g 1343 1525 1748 COF Static/Kinetic In/In 0.77/0.77 0.76/0.79 0.74/0.75 Out/Out 0.70/0.68 0.62/0.67 0.69/0.67 In/Out 0.72/0.70 0.75/0.73 0.60/0.65

    TABLE-US-00018 TABLE 15 Unit of Example 8. Three Layer Styrolux S/Kraton Film Property Measure G1726 Skins Skin Composition 90% Styrolux S/10% Kraton G1726 Core Composition 36% Adsyl 6C30F/24% Koattro DP8310M/ 20% Vistamaxx 3980FL/20% Kraton G1726 TD Shrink  60° C. % 0 0 0  65° C. % 6 4 5  70° C. % 26 23 16  75° C. % 29 28 30  80° C. % 42 42 44  85° C. % 53 53 51  90° C. % 60 60 58  95° C. % 66 64 65 100° C. % 69 67 70 105° C. % 71 70 72 Shrink Tension TD  80° C. grams 413 389 438  85° C. grams 411 432 490  90° C. grams 432 434 525  95° C. grams 451 447 508 100° C. grams 414 398 437 Natural Shrink TD  30° C. % 0.5 0.5 0.5  35° C. % 1.0 0.8 0.8  40° C. % 3.0 2.8 2.8  45° C. % 5.3 5.0 4.8

    [0156] As this example 8 illustrates, some reductions in optical properties (haze >6%) were observed with the incorporation of lower styrene content (<40% by weight) styrene-ethylene-co-butene block copolymer in the skin layer relative to previously described examples 6 and 7, which contained high styrene content (>40% by weight) styrene-ethylene-co-butene copolymer in the skins. TD shrink performance profile and stiffness properties of the films were very good.

    Example 9

    [0157] Three additional films, identified as example 9 as a group, were produced by coextrusion, cast on a sequence of two chill rolls at 35° C., stretched in machine direction (MID) 1.2× at 85° C., then stretched in a tenter frame at 96° C., cooled and wound up as described above. The films all contained skin layers with 80% Styrolux S in combination with Tuftec P1500 styrene-ethylene-co-butene-styrene triblock copolymer. The films vary only in the overall film thickness and smaller variations in the skin thickness. Properties are provided in tables 16 and table 17 below.

    TABLE-US-00019 TABLE 16 Unit of Example 9. Three Eayer Styrolux S/Tuftec Film Property Measure P1500 Skins Skin Composition 80% Styrolux S/20% Tuftec P1500 Core Composition 40% Adsyl 6C30F/27% Koattro DP8310M/ 33% Vistamaxx 3980FT Yield in.sup.2/lb 14,045 12,701 11,623 Density g/cm.sup.3 0.923 0.923 0.924 Film Thickness (calculated) microns 54 60 65 Skin Thickness (measured) microns 8.0 6.7 11.8 Haze % 7.1 7.3 8.1 Gloss-IN gu 81 79 82 Gloss-OUT gu 82 80 82 Gurley Stiffness MD/TD 8.8/10.6 13.6/13.8 15.3/15.8 Flex Stiffness MD/TD g/in 3.1/4.3 5.8/7.3 5.7/7.6 PIN Puncture g 1454 1718 1758

    TABLE-US-00020 TABLE 17 Unit of Example 9. Three Layer Styrolux S/Tuftec Film Property Measure P1500 Skins Skin Composition 80% Styrolux S/20% Tuftec P1500 Core Composition 40% Adsyl 6C30F/27% Koattro DP8310M/ 33% Vistamaxx 3980FL TD Shrink  60° C. % −0.5 −0.5 −0.5  65° C. % 2 2.5 2  70° C. % 13 13 12  75° C. % 27 26 26  80° C. % 41 40 41  85° C. % 51 51 50  90° C. % 57 58 57  95° C. % 62 63 63 100° C. % 67 67 67 105° C. % 71 70 70 Shrink Tension TD  80° C. grams 429 503 475  85° C. grams 423 491 491  90° C. grams 435 511 511  95° C. grams 464 495 500 100° C. grams 459 515 498 Natural Shrink TD  30° C. % −0.3 −0.3 −0.3  35° C. % 0 0 0  40° C. % 1.8 2.0 1.8  45° C. % 4.0 4.5 3.8

    [0158] Once again, some reduction in optical properties (haze >6) were observed in example 9 with the lower styrene content styrene-ethylene-co-butene-styrene triblock copolymer in the skin layers.

    [0159] In a third embodiment of the present invention, a three layer shrink film includes a core and opposed skin layers; said core being thicker than said skin layers. a hard resin is incorporated into the core formulation (alone or as a precompounded concentrate in propylene-ethylene-butene terpolymer). It has been found that this improves the overall stiffness of the film, raises the TD shrink initiation temperature of the film and improves storage temperature stability of the film, as well as improves the optical properties of the film with the addition of reclaim. Each of the skin layers includes one or more styrene-butadiene block copolymers and, optionally, one or more high styrene content polymers from the group consisting of styrene-ethylene-co-butene-styrene triblock copolymer, styrene-ethylene-co-propylene-styrene triblock copolymer, styrene-ethylene-co-butene diblock copolymer, styrene-ethylene-co-propylene diblock copolymer and combinations of said high styrene content triblock and diblock styrene copolymers. The core layer optionally includes one or more styrene tetrablock, triblock or diblock copolymers therein in combination with a propylene-ethylene-butene terpolymer, a butene-ethylene copolymer and a propylene-based elastomeric polymer. A representative film structure of this embodiment is shown below:

    [0160] Corona Treatment (optional)

    TABLE-US-00021 ~4-12 μm skin layer 80-100% (65% Styrolux S/35% Styrolux T SBC)  0-20% SEBS or SEP or SEPS 32-45 μm core layer  30-40% LYB Adsyl 6C30F Terpolymer  20-27% LYB Koattro DP8310M Polybutene-1 copolymer  15-33% Vistamaxx 3980FL or Versify 3000  0-20% Kraton G SEPSEP or SEBS or SEPS or SEP or SEB Block Copolymers  1-16% Plastolyn RI 140 or equivalent Hard Resin ~4-12 μm skin layer 80-100% (65% Styrolux S/35% Styrolux T SBC)  0-20% SEBS or SEP or SEPS

    [0161] Corona Treatment (optional)

    [0162] High styrene content triblock styrene-ethylene-co-butene-styrene or triblock styrene-ethylene-co-propylene-styrene or diblock styrene-ethylene-co-butene or diblock styrene-ethylene-co-propylene structures suitable to incorporate into the skin layer of this structure are commercially available from Asahi KASEI Corporation, Tokyo, Japan, and include the same triblock and diblock copolymers identified above with respect to the second embodiment of this invention.

    [0163] Hard Resin material suitable for incorporation into the polyolefin core are commercially available from Eastman Chemical Company, Kingsport, Tenn. and include: [0164] Plastolyn R1140, aliphatic, hydrogenated hydrocarbon resin with a Tg=91° C. and a MW=1,500 g/mol Regalite R1125, aliphatic, hydrogenated hydrocarbon resin with a Tg=70° C. and a MW=1,200 g/mol [0165] Regalrez 1126, aliphatic, hydrogenated hydrocarbon resin with a Tg=67° C. and a MW=1,250 g/mol [0166] Regalrez 6108, mixed aliphatic/aromatic, hydrocarbon resin with a Tg=55° C. and a MW=1,400 g/mol

    [0167] Hard Resin material suitable for incorporation into the polyolefin core also are commercially available from ExxonMobil, Houston, Tex. and include:

    [0168] Escorez 5340, cycloaliphatic hydrocarbon resin with a Tg=86° C. and a MW=730 g/mol

    [0169] Escorez 5637, cycloaliphatic hydrocarbon resin with a Tg=80° C. and a MW=820 g/mol

    Example 10

    [0170] Four additional films, identified as example 10 as a group, were fabricated by coextrusion, cast on a sequence of two chill rolls at 40° C., stretched in machine direction (MD) 1.1× at 85° C., then stretched in a tenter frame at 105° C., cooled and wound up as described above. The films all contained skin layers with a combination of Styrolux S and Styrolux T and a core composition varying with the substitution of polypropylene terpolymer with a precompounded blend of the terpolymer and hard resin(80% (80% Adsyl 6C30F/20% Plastolyn R4140) and the further introduction of Styrolux S and Styrolux T to the core at concentrations which simulate 15 wt. % reclaim. Properties are provided in tables 18 and table 19 below for two film thicknesses (52-53 μm and 59-63 μm respectively).

    TABLE-US-00022 TABLE 18 Unit of Example 10. Three Layer Symmetrical Styrolux Film Property Measure S/Styrolux T Skins Skin Composition 65% Styrolux S/35% Styrolux T Core Composition 36% (80% Adsyl 6C30F/ 36% (80% Adsyl 6C30F/20% 20% Plastolyn R1140) Plastolyn R1140) 24% Koattro DP8310M 21.5% Koattro DP8310M 20% Vistamaxx 3980FL 18.5% Vistamaxx 3980FL 20% Kraton G1645 19.5% Kraton G1645 3% Styrolux S/1.5% Styrolux T Yield in.sup.2/lb 14,438 13,816 Density g/cm.sup.3 0.944 0.953 Film Thickness (calculated) microns 52 53 Skin Thickness (measured) microns 9.8 9.5 Haze % 2.3 5.0 45° Gloss-IN gu >100 99 45° Gloss-OUT gu >100 100 Blocking RT, 150 psi, 24 hrs g/in No blocking 35° C., 150 psi, 3 hrs g/in No blocking Gurley Stiffness MD/TD 9.8/11.9 8.0/10.5 Flex Stiffness MD/TD g/in 3.8/4.6 3.6/4.3 TD Shrink  60° C. % 0.3 1  65° C. % 6 8  70° C. % 17 19  75° C. % 31 33  80° C. % 42 44  85° C. % 50 52  90° C. % 57 58  95° C. % 64 64 100° C. % 69 68 105° C. % 73 72 Shrink Tension TD  80° C. grams 201 232  85° C. grams 231 197  90° C. grams 204 243  95° C. grams 226 262 100° C. grams 215 228 Natural Shrink TD  30° C. % 0.5 0.0  35° C. % 0.5 1.0  40° C. % 3.0 3.5  45° C. % 3.0 3.0

    TABLE-US-00023 TABLE 19 Unit of Example 10. Three Layer Symmetrical Styrolux Film Property Measure S/Styrolux T Skins Skin Composition 65% Styrolux S/35% Styrolux T Core Composition 36% (80% Adsyl 6C30F/ 36% (80% Adsyl 20% Plastolyn R1140) 6C30F/20% Plastolyn 24%Koattro DP8310M R1140) 20% Vistamaxx 3980FL 21.5% Koattro DP8310M 20% Kraton G1645 18.5% Vistamaxx 3980FL 19.5% Kraton G1645 3% Styrolux S/1.5% Styrolux T Yield in.sup.2/lb 11,741 12,753 Density g/cm.sup.3 0.942 0.939 Film Thickness (calculated) microns 63 59 Skin Thickness (measured) microns 11.3 10.4 Haze % 2.5 5.5 45° Gloss-IN gu >100 96 45° Gloss-OUT gu >100 99 Blocking RT, 150 psi, 24 hrs g/in No blocking 35° C., 150 psi, 3 hrs g/in No blocking Gurley Stiffness MD/TD —/— 9.2/— Flex Stiffness MD/TD g/in —/— 4.5/4.9 TD Shrink  60° C. % 0.3 1  65° C. % 5 8  70° C. % 16 18  75° C. % 29 32  80° C. % 41 43  85° C. % 50 52  90° C. % 57 59  95° C. % 64 65 100° C. % 68 70 105° C. % 71 73 Shrink Tension TD  80° C. grams 241 217  85° C. grams 256 210  90° C. grams 227 228  95° C. grams 248 221 100° C. grams 237 232 Natural Shrink TD  30° C. % 0.0 0.0  35° C. % 0.5 0.5  40° C. % 2.5 3.5  45° C. % 2.0 3.0

    [0171] Introduction of hard resin in the core raises the TD shrink initiation temperature and improves the natural shrink stability of the film. With the addition of skin polymer in the core at the level which simulates 15% reclaim, the film haze is still below the target level of 6%.

    [0172] In a fourth embodiment of the present invention a three layer shrink film includes a core layer and opposed skin layers. In this embodiment the film structure is symmetric, with one or more styrene-butadiene block copolymers (diblock or triblock) as the opposing skin layers. The core layer includes one or more styrene-butadiene triblock or diblock copolymers, one or more styrene-ethylene-co-butene-styrene triblock or styrene-ethylene-co-butene diblock copolymers therein, in combination with a propylene-ethylene-butene terpolymer or propylene-ethylene copolymer, a butene-ethylene copolymer and a propylene-based elastomeric polymer.

    [0173] This core layer composition is the result of simulating the addition of reclaim into the core It has been found that the addition of reclaim at these levels creates significant opacity to the film. Optionally, the addition of a TiO2 concentrate with an polyethylene based carrier is present to enhance the films opacity and whiteness. A representative film structure of this sixth embodiment including the optional components is shown below.

    [0174] Corona Treatment (optional)

    TABLE-US-00024 ~4-12 μm skin layer 80-100% (60-90% Styrolux S/10-40% Styrolux T SBC)  0-20% ((SEBS or SEP or SEPS)) 30-45 μm core layer  20-35% LYB Adsyl 6C30F Terpolymer or Adsyl 7415 XCP  10-25% LYB Koattro DP8310M Polybutene-1 copolymer  10-30% Vistamaxx 3980FL or Versify 3000  10-60% Reclaim (Terpolymer, butene-ethylene copolymer, propylene-based elastomer, styrene ethylene-co- butene-styrene block copolymer, styrene- butadiene block copolymer)  0-10% Polyethylene based TiO2 concentrate ~4-12 μm skin layer 80-100% (60-80% Stryolux S/20-40% Styrolus T SBC)  0-20% ((SEBS or SEP or SEPS))

    [0175] Corona Treatment (optional)

    Example 11

    [0176] As described hereinafter, films employing at least 10% reclaim in the core are within the scope of this invention. Four additional films, identified as example 11 as a group, were fabricated by coextrusion, cast on a sequence of two chill rolls at 40° C., stretched in machine direction (MD) 1.1× at 85° C., then stretched in a tenter frame at 105° C., cooled and wound up as described above. Reclaim addition to the core was simulated by adding to the core the two component blend of the PS block copolymers used in the skin layer of the above-described films, in a quantity that constitutes 10% by weight of the composition of the core. Details of the formulation are specified in Table 20 below. Table 20 shows the composition and properties for four (4) films including the simulated 10% recycle material in the core; these films differing from each other only in skin and film thickness. As shown in Table 20, haze values were obtained in the range of approximately 4-5%, which is an acceptable range (criteria is less than 6%). Moreover, the simulation of employing 10% reclaim in the core, by introducing into the core the polystyrene blend employed in the skins, had no noticeable effect on other relevant properties of the film (gloss, blocking, puncture resistance, etc.). Higher levels of reclaim may be usable in this invention without adversely affecting other desired properties of the film. Since the use of reclaim material can provide a significant cost benefit, as compared to using virgin material, it would be desirable to use the highest possible percentage of reclaim that does not adversely affect other desired properties of the film.

    TABLE-US-00025 TABLE 20 Unit of Example 11. Three layer Symmetrical Film with Film Property Measure Styrolux S/Styrolux T Skins-Reclaim Simulation at 10% Skin Composition 65% Styrolux S/35% Styrolux T Core Composition 36% Adsyl 6C30F/22% Koattro DP8310M/19% Vistamaxx 3980FL/20% Kraton G1645/2% Styrolux S/1% Styrolux T Yield in.sup.2/lb 14,959 14,605 13,961 13,593 Density g/cm.sup.3 0.927 0.933 0.936 0.944 Film Thickness (calculated) microns 51 52 54 55 Skin Thickness (measured) microns 6.1 7.8 8.6 10.1 Haze % 5.1 4.1 4.6 3.8 45° Gloss-IN gu 97 >100 >100 >100 45° Gloss-OUT gu 97 100 100 >100 Blocking RT, 150 psi, 24 hrs g/in No blocking 35° C, 150 psi, 3 hrs g/in No blocking Gurley Stiffness MD/TD 7.1/8.3 7.3/9.9 11.1/9.8 10.4/13.4 Flex Stiffness MD/TD g/in 3.0/3.7 3.1/3.8 3.8/4.5 4.4/5.1 PIN Puncture g 1,291 1,270 1,333 1,307 COF Static/Kinetic In/In 0.56/0.56 0.63/0.63 0.60/0.57 0.49/0.49 Out/Out 0.55/0.55 0.49/0.50 0.51/0.50 0.52/0.50 In/Out 0.57/0.58 0.53/0.54 0.55/0.56 0.50/0.49

    [0177] The addition of “reclaim” to the core also did not have any measurable effects on the shrink performance or shrink tension of the film structure, as shown in Table 21 below.

    TABLE-US-00026 TABLE 21 Example 11. Three layer Symmetrical Film Unit of with Styrolux S/Styrolux T Skins-Reclaim Film Property Measure Simulation at 10% Skin Composition 65% Styrolux S/35% Styrolux T Core Composition 36% Adsyl 6C30F/22% Koattro DP8310M/ 19% Vistamaxx 3980FL/20% Kraton G1645/ 2% Styrolux S/1% Styrolux T TD Shrink  60° C. % 2 2 1 1  65° C. % 11 11 10 10  70° C. % 24 22 23 22  75° C. % 35 34 35 34  80° C. % 44 44 44 44  85° C. % 51 50 51 52  90° C. % 58 57 59 60  95° C. % 64 63 64 65 100° C. % 68 68 68 69 105° C. % 71 70 70 71 Shrink Tension TD  80° C. grams 236 310 317 302  85° C. grams 293 315 307 299  90° C. grams 296 320 329 310  95° C. grams 290 335 330 312 100° C. grams 288 359 317 319 Natural Shrink MD/TD  30° C. % −0.5/0.5 −0.5/0.5 −0.5/0.5 −0.5/0.5  35° C. % −0.5/1.0 −0.5/1.0 −0.5/1.0 −0.5/1.0  40° C. % −0.5/4.5 −0.5/4.5 −0.5/4.2 −0.5/4.2  45° C. %   0/8.0   0/8.0   0/7.5   0/6.0

    Example 12

    [0178] Higher levels of reclaim incorporation into the core of the film (>30%) produces a moderate level of opacity in the film while maintaining the desirable floatability of the structure. Film structures with higher levels of reclaim provide a cost effective approach for the introduction of floatable solid white shrink film. Three additional films, identified as example 12 as a group, were fabricated by coextrusion, cast on a sequence of two chill rolls at 40° C., stretched in machine direction (MD) 1.2× at 80° C., then stretched in a tenter frame at 108° C., cooled and wound up as described above. The films all contained skin layers with a combination of Styrolux S and Styrolux T and the core layer includes one or more styrene-butadiene triblock or diblock copolymers, one or more styrene-ethylene-co-butene-styrene triblock or styrene-ethylene-co-butene diblock copolymers therein, in combination with a propylene-ethylene-butene terpolymer or propylene-ethylene copolymer, a butene-ethylene copolymer and a propylene-based elastomeric polymer. This core layer composition is the result of simulating the incorporating of reclaim into the core at levels (simulation of 75% reclaim) which create significant opacity to the film.

    TABLE-US-00027 TABLE 22 Unit of Example 12. Three Layer Symmetric Film- Film Property Measure Reclaim Simulation at 75% Skin Composition 80% Styrolux S/20% Styrolux T Core Composition 27% Adsyl 6C30F/17% Koattro DP8310M/ 20% Vistamaxx 3980FL/25% Styrolux S/ 6% Styrolux T/5% Kraton G1643 Yield in.sup.2/lb 13,902 13,076 23,687 Density g/cm.sup.3 0.962 0.958 0.961 Film Thickness (calculated) microns 53 56 58 Skin Thickness (measured) microns 9.6 11.0 10.1 Opacity % 23 24 24 Opacity after shrink at 95 C. % 28 31 30 Gloss-IN gu 88 89 92 Gloss-OUT gu 88 88 88 Gurley Stiffness MD/TD 10.6/9.9  12.7/14.7 16.7/15.0 Flex Stiffness MD/TD g/in 4.6/4.9 5.7/6.4 6.0/6.5 PIN Puncture g 958 1070 1102

    TABLE-US-00028 TABLE 23 Unit of Example 12. Three Layer Symmetric Film- Film Property Measure Reclaim Simulation at 75% Skin Composition 80% Styrolux S/20% Styrolux T Core Composition 27% Adsyl 6C30F/17% Koattro DP8310M/ 20% Vistamaxx 3980FL/25% Styrolux S/6% Styrolux T/5% Kraton G1643 TD Shrink  60° C. % −1 −1 −1  65° C. % 1 1.5 1.3  70° C. % 11 12 11  75° C. % 24 24 25  80° C. % 37 38 38  85° C. % 46 47 47  90° C. % 54 54 55  95° C. % 61 62 61 100° C. % 67 66 67 105° C. % 70 72 72 Shrink Tension TD  80° C. grams 229 240 236  85° C. grams 229 217 220  90° C. grams 216 218 218  95° C. grams 225 212 226 100° C. grams 251 208 233 Natural Shrink TD  30° C. % 0 −0.3 −0.3  35° C. % −0.2 −0.2 −0.2  40° C. % 1.3 1 1.3  45° C. % 1.5 1.5 1.5

    [0179] As shown in tables 22 and 23 above, an attractive balance of properties (density, stiffness, TD shrink performance, and good storage temperature stability) is maintained even at very high levels of reclaim.

    Example 13

    [0180] As a further illustration of higher levels of reclaim to provide a cost effective approach for the introduction of floatable solid white shrink film, three additional films, identified as example 13 as a group, were fabricated by coextrusion, cast on a sequence of two chill rolls at 40° C., stretched in machine direction (MD) 1.2× at 80° C., then stretched in a tenter frame at 108° C., cooled and wound up as described above. The films all contained skin layers with a combination of Styrolux S and Styrolux T and the core layer includes one or more styrene-butadiene triblock or diblock copolymers, one or more styrene-ethylene-co-butene-styrene triblock or styrene-ethylene-co-butene diblock copolymers therein, in combination with a propylene-ethylene-butene terpolymer or propylene-ethylene copolymer, a butene-ethylene copolymer and a propylene-based elastomeric polymer. This core layer composition is the result of simulating the incorporating of reclaim into the core at levels (simulation of 100% reclaim) which create significant opacity to the film.

    TABLE-US-00029 TABLE 24 Unit of Example 13. Three Eayer Symmetric Film- Film Property Measure Reclaim Simulation at 100% Skin Composition 80% Styrolux S/20% Styrolux T Core Composition 22.2% Adsyl 6C30F/13.2% Koattro DP8310M/16.2% Vistamaxx 3980FT/ 34.7% Styrolux S/8.7% Styrolux T/5% Kraton G1643 Yield in.sup.2/lb 16,941 14,854 13,903 Density g/cm.sup.3 0.959 0.971 0.970 Film Thickness (calculated) microns 43 49 52 Skin Thickness (measured) microns 8.7 12.0 11.1 Opacity % 18 18 20 Opacity after shrink at 95 C. % 27 27 27 Gloss-IN gu >100 >100 99 Gloss-OUT gu 99 >100 98 Gurley Stiffness MD/TD 6.6/6.9 13.9/11.4 9.6/11.8 Flex Stiffness MD/TD g/in 2.7/3.1 3.8/4.2 5.1/5.7 PIN Puncture g 815 920 947

    TABLE-US-00030 TABLE 25 Unit of Example 13. Three Layer Symmetric Film- Film Property Measure Reclaim Simulation at 100% Skin Composition 80% Styrolux S/20% Styrolux T Core Composition 22.2% Adsyl 6C30F/13.2% Koattro DP8310M/16.2% Vistamaxx 3980FL/34.7% Styrolux S/8.7% Styrolux T/5% Kraton G1643 TD Shrink  60° C. % −1 −1 −1  65° C. % 1 1.3 1.2  70° C. % 12 12 12  75° C. % 27 28 27  80° C. % 42 42 41  85° C. % 43 45 44  90° C. % 59 59 61  95° C. % 66 67 66 100° C. % 71 72 70 105° C. % 74 75 74 Shrink Tension TD  80° C. grams 239 250 238  85° C. grams 237 247 243  90° C. grams 236 222 243  95° C. grams 234 232 239 100° C. grams 209 211 224 Natural Shrink TD  30° C. % −0.2 −0.2 0  35° C. % −0.2 −0.2 −0.2  40° C. % 1.2 1 1  45° C. % 1.5 1.5 1.5

    [0181] Once again, as shown in tables 24 and 25 above, an attractive balance of properties (density, stiffness, TD shrink performance, and good storage temperature stability) is maintained even at the extreme level of a core structure which simulates a 100% reclaim composition.

    [0182] In a fifth embodiment of the present invention a three layer shrink film includes a core layer and opposed skin layers; said skin layers being thinner than said core layer. In this embodiment the film structure is asymmetric, including one or more amorphous ethylene-norbornene polymers as one of the skin layers and one or more styrene-butadiene block copolymers (diblock or triblock) as the opposing skin layer. Hard resin can optionally be incorporated into the core formulation (alone or as a precompounded concentrate in Adsyl terpolymer) to improve the overall stiffness of the film and/or raise the TD shrink initiation temperature of the film and improve storage temperature stability of the film and/or improve the optical properties of the film with the addition of reclaim. The skin layer including one or more styrene-butadiene block copolymers (diblock or triblock) optionally includes one or more high styrene content polymers from the group consisting of styrene-ethylene-co-butene-styrene triblock copolymers, styrene-ethylene-co-propylene-styrene triblock copolymers, styrene-ethylene-co-butene diblock copolymers, styrene-ethylene-co-propylene diblock copolymers and combinations of said high styrene content triblock and diblock copolymers. The core layer optionally includes one or more styrene tetrablock, triblock or diblock copolymers therein, in combination with a propylene-ethylene-butene terpolymer, a butene-ethylene copolymer and a propylene-based elastomeric polymer. Also, a hard resin optionally can be included in the core. A representative film structure of this fourth embodiment including the optional components is shown below.

    [0183] Corona Treatment (optional)

    TABLE-US-00031 ~4-12 μm skin layer 80-100% (80% Styrolux S/20% Styrolux T SBC) 0-20% SEBS or SEP or SEPS 32-45 μm core layer 30-40% LYB Adsyl 6C30F Terpolymer 20-27% LYB Koattro DP8310M Polybutene-1 copolymer 20-33% Vistamaxx 3980FL or Versify 3000 0-20% Kraton G SEPSEP or SEBS or SEPS or SEP or SEB Block Copolymers 0-12% Plastolyn R1140 or equivalent Hard Resin ~4-12 μm skin layer 100% 35-65% Topas 8007F-600 COC 65-35% Topas 9506F-500 COC

    [0184] Corona Treatment (optional)

    [0185] In the above asymmetric film structure, the presence of a propylene based elastomer (Vistamaxx or Versify) in the core layer ensures an appropriate level of adhesion of the COC blend skin to the olefin core structure. The presence of a COC blend skin affects the shrink initiation temperature and the rate of the shrink response with temperature (i.e., the slope of the plot of shrink response with temperature). This asymmetric structure also reduces the level of high refractive index styrene copolymer present in the core (with the incorporation of edge trim and reclaim) which can adversely affect the optical properties of the film.

    [0186] High styrene content triblock styrene-ethylene-co-butene-styrene or triblock styrene-ethylene-co-propylene-styrene or diblock styrene-ethylene-co-butene or diblock styrene-ethylene-co-propylene structures suitable to incorporate into the skin layer of this structure are commercially available from Asahi KASEI Corporation, Tokyo, Japan and include the same triblock and diblock copolymers identified above with respect to the second embodiment of this invention. In addition, the hard resins usable in this invention include the same hard resins identified above with respect to the third embodiment of this invention.

    Example 14

    [0187] Three additional films, identified as example 14 as a group, were fabricated by coextrusion, cast on a sequence of two chill rolls at 35° C., stretched in machine direction (MID) 1.2× at 85° C., then stretched in a tenter frame at 99° C., cooled and wound up as described above. The films all contained asymmetric skin layers with a combination of Styrolux S and Styrolux T on one side and a combination of 8007F-600 COC and 9506F-500 COC on the other side. Properties are provided in tables 26 and table 27 below.

    TABLE-US-00032 TABLE 26 Unit of Film Property Measure Example 14. Asymmetric Skin Structure Skin Composition IN 80% Styrolux S/20% Styrolux T OUT 40% Topas 8007F-600/60% Topas 9506F- 500 Core Composition 40% Adsyl 6C30F/20% Koattro DP8310M/ 20% Vistamaxx 3980FL/20% Kraton G1657 Yield in.sup.2/lb 15,241 13,903 13,516 Density g/cm.sup.3 0.927 0.923 0.926 Film Thickness microns 50 55 57 (calculated) Skin Thickness microns 10.3 7.2 11.3 (measured) Haze % 1.0 0.8 0.9 Gloss-IN gu >100 >100 >100 Gloss-OUT gu 99 >100 100 Blocking RT, 150 psi, 24 hrs g/in No blocking 35° C., 150 psi, 3 hrs g/in No blocking Gurley Stiffness MD 8.1 10.1 13.8 Flex Stiffness g/in 4.2/5.4 3.8/5.1 5.2/6.9 MD/TD PIN Puncture g 1122 1284 1298

    TABLE-US-00033 TABLE 27 Unit of Film Property Measure Example 14. Asymmetric Skin Structure Skin Composition IN 80% Styrolux S/20% Styrolux T OUT 40% Topas 8007F-600/60% Topas 9506F- 500 Core Composition 40% Adsyl 6C30F/20% Koattro DP8310M/ 20% Vistamaxx 3980FL/20% Kraton G1657 TD Shrink  60° C. % 0 0 0  65° C. % 5 5 5  70° C. % 13 14 13  75° C. % 28 28 28  80° C. % 46 44 46  85° C. % 53 54 53  90° C. % 61 62 62  95° C. % 67 67 68 100° C. % 70 72 71 105° C. % 74 73 74 Shrink Tension TD  80° C. grams 476 467 525  85° C. grams 493 512 604  90° C. grams 562 540 605  95° C. grams 501 532 574 100° C. grams 509 508 492 Natural Shrink TD  30° C. % 0.5 0.5 0.5  35° C. % 1.0 1.0 1.0  40° C. % 3.5 3.0 3.25  45° C. % 5.0 5.25 5.25

    [0188] The use of asymmetric skins leads to excellent optical properties, very good film stiffness, and good natural shrink stability.

    [0189] In a sixth embodiment of the present invention a five layer shrink film includes a core layer, opposed skin layers and two intermediate adhesive layers interposed between the core and the two skin layers; said intermediate adhesive layers and skin layers being thinner than said core layer. In this embodiment the film structure is symmetric, with one or more styrene-butadiene block copolymers (diblock or triblock) as the opposing skin layers and intermediate layers consisting of blends of one or more polymers from the group consisting of styrene-ethylene-co-butene-styrene triblock copolymer, styrene-ethylene-co-propylene-styrene triblock copolymer, styrene-ethylene-co-butene diblock copolymer, styrene-ethylene-co-propylene diblock copolymer and at least one or more polypropylene terpolymer or copolymer. The core layer optionally includes one or more styrene tetrablock, triblock or diblock copolymers therein, in combination with a propylene-ethylene-butene terpolymer, a butene-ethylene copolymer and a propylene-based elastomeric polymer.

    [0190] Also, a hard resin optionally can be included in the core formulation (alone or as a precompounded concentrate in polypropylene terpolymer) to improve the overall stiffness of the film and/or raise the TD shrink initiation temperature of the film and improve storage temperature stability of the film and/or improve the optical properties of the film with the addition of reclaim. A representative film structure of this sixth embodiment including the optional components is shown below.

    [0191] Corona Treatment (optional)

    TABLE-US-00034 ~4-12 μm skin layer 80-100% (65-100% Styrolux S/0-35% Styrolux T SBC) 0-20% (SEBS or SEP or SEPS) 1.5-4.5 μm inter. layer 60-95% Kraton G SEBS or SEPS Block Copolymer 5-40% LYB 6C30F Terpolymer or Total 8573 Copolymer 30-45 μm core layer 30-40% LYB Adsyl 6C30F Terpolymer or Adsyl 7415XCP 20-27% LYB Koattro DP8310M Polybutene-1 copolymer 20-33% Vistamaxx 3980FL or Versify 3000 0-20% Kraton G SEPSEP or SEBS or SEPS or SEP or SEB Block Copolymers 0-16% Plastolyn RI 140 or equivalent Hard Resin 1.5-4.5 μm inter. layer 60-95% Kraton G SEBS or SEPS Block Copolymer 5-40% LYB 6C30F Terpolymer or Total 8573 Copolymer ~4-12 μm skin layer 80-100% (65-100% Styrolux S/0-35% Styrolux T SBC) 0-20% ((SEBS or SEP or SEPS))

    [0192] Corona Treatment (optional)

    Example 15

    [0193] Three additional films, identified as example 15 as a group, were fabricated by coextrusion, cast on a sequence of two chill rolls at 35° C., stretched in machine direction (MD) 1.2× at 85° C., then stretched in a tenter frame at 103° C., cooled and wound up as described above. The films all contained skin layers with a combination of 80% Styrolux S and 20% Styrolux T. and a core composition comprising polypropylene terpolymer, polybutene-1 copolymer, and propylene-ethylene elastomeric copolymer. The intermediate layers are a blend of 65% Kraton G1643 and 35% Adsyl 6C30F. Properties are provided in tables 28 and table 29 below.

    TABLE-US-00035 TABLE 28 Unit of Example 15. Five Layer Symmetric Film Property Measure Film Skin Composition 80% Styrolux S/20% Styrolux T Interlayer Composition 65% Kraton G1643/35% Adsyl 6C30F Core Composition 40% Adsyl 6C30F/26.7% Koattro DP8310M/33.3% Vistamaxx 3980FL Yield in.sup.2/lb 14,505 14,273 13,109 Density g/cm.sup.3 0.933 0.935 0.937 Film Thickness (calculated) microns 52 53 57 Interlayer Thickness microns 4.1 3.3 4.3 (measured) Skin Thickness (measured) microns 8.6 9.5 8.4 Haze % 1.4 1.5 0.9 Gloss-IN gu >100 >100 >100 Gloss-OUT gu >100 >100 100 Blocking RT, 150 psi, 24 hrs g/in No blocking 35° C, 150 psi, 3 hrs g/in No blocking Gurley Stiffness MD/TD 10.0/9.5  13.6/12.7 16.3/14.2 Flex StiffnessMD/TD g/in 5.1/5.6 4.1/4.8 5.9/6.1 PIN Puncture g 1417 1208 1395 COF Static/Kinetic 0.72/0.63 0.73/0.59   In/In 0.75/0.75 0.95/0.80   Out/Out 0.80/0.71 0.68/0.65   In/Out

    TABLE-US-00036 TABLE 29 Unit of Example 15. Five Layer Symmetric Film Property Measure Film Skin Composition 80% Styrolux S/20% Styrolux T Interlayer Composition 65% Kraton G 1643/35% Adsyl 6C30F Core Composition 40% Adsyl 6C30F/26.7% Koattro DP8310M/33.3% Vistamaxx 3980FL TD Shrink  60° C. % 1.5 1.7 1.5  65° C. % 10 10 9  70° C. % 21 21 21  75° C. % 27 27 26  80° C. % 41 43 40  85° C. % 52 52 51  90° C. % 59 59 60  95° C. % 64 63 64 100° C. % 68 69 70 105° C. % 71 71 72 Shrink Tension TD  80° C. grams 309 304 345  85° C. grams 368 350 406  90° C. grams 355 353 411  95° C. grams 337 331 370 100° C. grams 321 334 336 Natural Shrink TD  30° C. % 0.5 0.5 0.5  35° C. % 1.0 1.0 1.0  40° C. % 1.5 1.0 1.25  45° C. % 6.5 6.25 6.5

    [0194] The five layer films exhibit an excellent balance of optics, stiffness, and TD shrink performance. The natural shrink stability under normal storage conditions (≤40° C.) for the five layer structure is significantly improved relative to a 3 layer structure with the same styrene-ethylene/butene-styrene triblock elastomer in the core (described in example 4).

    Example 16

    [0195] Three additional films, identified as example 16 as a group, were fabricated by coextrusion, cast on a sequence of two chill rolls at 40° C., stretched in machine direction (MD) 1.2× at 80° C., then stretched in a tenter frame at 108° C., cooled and wound up as described above. The films all contained skin layers with a combination of 90% Styrolux S and 10% Styrolux T. and a core composition comprising polypropylene terpolymer, polybutene-1 copolymer, and propylene-ethylene elastomeric copolymer. The intermediate layers are a blend of 70% Kraton G1643 and 30% Adsyl 6C30F. Properties are provided in tables 30 and table 31 below.

    TABLE-US-00037 TABLE 30 Unit of Example 16. Five Layer Symmetric Film Property Measure Film Skin Composition 90% Styrolux S/10% Styrolux T Interlayer Composition 70% Kraton G1643/30% Adsyl 6C30F Core Composition 40% Adsyl 6C30F/26.7% Koattro DP8310M/33.3% Vistamaxx 3980FL Yield in.sup.2/lb 18,158 16,660 16,016 Density g/cm.sup.3 0.940 0.933 0.936 Film Thickness (calculated) microns 41 45 47 Interlayer Thickness microns 3.6 3.8 3.8 (measured) Skin Thickness (measured) microns 6.8 10.8 9.6 Haze % 1.2 0.9 1.4 Gloss-IN gu >100 >100 >100 Gloss-OUT gu >100 >100 >100 Gurley Stiffness MD/TD 6.5/7.2 5.9/9.5 7.2/7.9 Flex Stiffness MD/TD g/in 2.5/3.0 2.1 /2.4 4.0/5.4

    TABLE-US-00038 TABLE 31 Unit of Example 16. Five Layer Symmetric Film Property Measure Film Skin Composition 90% Styrolux S/10% Styrolux T Interlayer Composition 70% Kraton G 1643/30% Adsyl 6C30F Core Composition 40% Adsyl 6C30F/26.7% Koattro DP8310M/33.3% Vistamaxx 3980FL TD Shrink  60° C. % −1 −1 −1  65° C. % 1 1 1  70° C. % 13 12 11  75° C. % 28 27 28  80° C. % 39 38 38  85° C. % 50 51 50  90° C. % 62 62 62  95° C. % 62 62 62 100° C. % 70 69 69 105° C. % 72 71 72 Shrink Tension TD  85° C. grams 169 174 199  90° C. grams 232 195 226  95° C. grams 212 209 241 100° C. grams 213 206 234 Natural Shrink TD  35° C. % 0 0 0  40° C. % 0 0 0  45° C. % 2.5 2.5 2.5

    [0196] The five layer films exhibit an excellent balance of optics, stiffness, and TD shrink performance. The natural shrink under normal storage conditions (≤40° C.) exhibits a high degree of stability (no TD dimensional change for 24 hours) for the five layer structure.

    Example 17

    [0197] Three additional films, identified as example 17 as a group, were fabricated by coextrusion, cast on a sequence of two chill rolls at 40° C., stretched in machine direction (MD) 1.2× at 80° C., then stretched in a tenter frame at 105° C., cooled and wound up as described above. The films all contained skin layers of 100% Styrolux S and a core composition comprising polypropylene terpolymer, polybutene-1 copolymer, and propylene-ethylene elastomeric copolymer. The intermediate layers are a blend of 70% Kraton G1643 and 30% Adsyl 6C30F. Properties are provided in tables 32 and table 33 below.

    TABLE-US-00039 TABLE 32 Unit of Example 17. Five Layer Symmetric Film Property Measure Film Skin Composition 100% Styrolux S Interlayer Composition 70% Kraton G1643/30% Adsyl 6C30F Core Composition 40% Adsyl 6C30F/26.7% Koattro DP8310M/33.3% Vistamaxx 3980FL Yield in.sup.2/lb 18,809 Density g/cm.sup.3 0.935 0.940 0.943 Film Thickness (calculated) microns 40 43 45 Interlayer Thickness microns 3.2 2.8 3.1 (measured) Skin Thickness (measured) microns 7.1 8.0 9.4 Haze % 1.0 0.6 0.5 Gloss-IN gu >100 >100 >100 Gloss-OUT gu >100 >100 >100 Gurley Stiffness MD/TD 8.5/6.7 6.4/7.5 8.4/8.4 Flex StiffnessMD/TD g/in 1.7/2.2 2.3/2.7 2.8/3.1

    TABLE-US-00040 TABLE 33 Unit of Example 17. Five Layer Symmetric Film Property Measure Film Skin Composition 100% Styrolux S Interlayer Composition 70% Kraton G 1643/30% Adsyl 6C30F Core Composition 40% Adsyl 6C30F/26.7% Koattro DP8310M/33.3% Vistamaxx 3980FL TD Shrink  60° C. % −1 −1 −1  65° C. % 0 0 0  70° C. % 9 12 11  75° C. % 26 26 26  80° C. % 38 38 38  85° C. % 49 47 46  90° C. % 63 63 63  95° C. % 63 63 63 100° C. % 68 69 68 105° C. % 72 71 71 Shrink Tension TD  85° C. grams 183 193 230  90° C. grams 227 179 222  95° C. grams 211 177 218 100° C. grams 213 237 218 Natural Shrink TD  35° C. % 0 0 0  40° C. % 0 0 10  45° C. % 1.5 1.5 1.5

    [0198] The five layer films exhibit an excellent balance of optics, stiffness, and TD shrink performance. The natural shrink under normal storage conditions (≤40° C.) exhibits an exceptional degree of stability (no TD dimensional change for 24 hours) for the five layer structure.

    Example 18

    [0199] Three additional films, identified as example 18 as a group, were produced by coextrusion, cast on a sequence of two chill rolls at 40° C., stretched in machine direction (MD) 1.2× at 80° C., then stretched in a tenter frame at 108° C., cooled and wound up as described above. The films all contained skin layers with a combination of 80% Styrolux S and 20% Styrolux T. and a core composition comprising fractional melt flow polypropylene-ethylene copolymer, polybutene-1 copolymer, and propylene-ethylene elastomeric copolymer. The intermediate layers are a blend of 70% Kraton G1643 and 30% Total 8573 high ethylene copolymer. Properties are provided in tables 34 and table 35 below.

    TABLE-US-00041 TABLE 34 Unit of Example 18. Five Layer Symmetric Film Property Measure Film Skin Composition 80% Styrolux S/20% Styrolux T Interlayer Composition 70% Kraton G1643/30% Total 8573 Core Composition 40% Adsyl 7415 XCP/26.7% Koattro DP8310M/33.3% Vistamaxx 3980FL Yield in.sup.2/lb 13,018 12,761 12,211 Density g/cm.sup.3 0.934 0.937 0.938 Film Thickness (calculated) microns 58 59 61 Interlayer Thickness microns 5.4 5.2 4.1 (measured) Skin Thickness (measured) microns 10.8 10.6 10.2 Haze % 2.2 2.7 2.4 Gloss-IN gu >100 >100 >100 Gloss-OUT gu >100 >100 >100 Gurley Stiffness MD/TD 12.1/15.1 14.9/16.4 14.5/15.7 Flex StiffnessMD/TD g/in 5.6/6.1 6.6/7.1 7.3/8.1 PIN Puncture g 1111 1070 1162

    TABLE-US-00042 TABLE 35 Unit of Example 18. Five Layer Symmetric Film Property Measure Film Skin Composition 80% Styrolux S/20% Styrolux T Interlayer Composition 70% Kraton G1643/30% Total 8573 Core Composition 40% Adsyl 7415 XCP/26.7% Koattro DP8310M/33.3% Vistamaxx 3980FL TD Shrink  60° C. % 0 0 −0.3  65° C. % 4 4 4  70° C. % 14 14 14  75° C. % 25 25 26  80° C. % 33 32 34  85° C. % 39 39 40  90° C. % 46 46 47  95° C. % 52 53 54 100° C. % 57 57 59 105° C. % 63 64 64 Shrink Tension TD  80° C. grams 458 426 433  85° C. grams 453 425 431  90° C. grams 458 428 462  95° C. grams 447 425 462 100° C. grams 481 469 460 Natural Shrink TD  30° C. % 0 0 0  35° C. % 0.5 0.5 0.5  40° C. % 2.5 2.5 2.5  45° C. % 3 3 3

    [0200] The five layer films of example 18 illustrate propylene-ethylene copolymers can be substituted for the terpolymer component of the interlayer composition while retaining key performance characteristics of the film (floatability, haze <6%, shrink at 95° C.>500%). Some increase in shrink tension and a reduction of natural shrink at the highest temperature (45° C.) was observed relative to the films of example 15, consistent with the greater rigidity of the copolymer.

    Example 19

    [0201] Three additional films, identified as example 19 as a group, were produced by coextrusion, cast on a sequence of two chill rolls at 40° C., stretched in machine direction (MD) 1.2× at 80° C., then stretched in a tenter frame at 105° C., cooled and wound up as described above. The films all contained skin layers with a combination of 80% Styrolux S and 20% Styrolux T. and a core composition comprising fractional melt flow polypropylene-ethylene copolymer, polybutene-1 copolymer, and propylene-ethylene elastomeric copolymer. The intermediate layers are a blend of 700% Kraton G1643 and 30% Adsyl 6C30F terpolymer. Substituting a fractional melt flow rate propylene-ethylene copolymer in the film core in place of the higher melt flow rate terpolymer of examples 15 provides improvements in extrusion stability and extrudate melt strength. Properties are provided in tables 36 and table 37 below.

    TABLE-US-00043 TABLE 36 Unit of Example 19. Five Layer Symmetric Film Property Measure Film Skin Composition 80% Styrolux S/20% Styrolux T Interlayer Composition 70% Kraton G1643/30% Adsyl 6C30F Core Composition 40% Adsyl 7415 XCP/26.7% Koattro DP8310M/33.3% Vistamaxx 3980FL Yield in.sup.2/lb 20,313 17,201 16,901 Density g/cm.sup.3 0.953 0.958 0.946 Film Thickness (calculated) microns 36 43 44 Interlayer Thickness microns 3.7 3.5 4.7 (measured) Skin Thickness (measured) microns 7.9 10.0 10.5 Haze % 1.1 1.0 1.5 Gloss-IN gu >100 >100 >100 Gloss-OUT gu >100 >100 >100 Gurley Stiffness MD/TD 4.3/3.9 5.0/6.0 7.3/7.2 Flex StiffnessMD/TD g/in 1.7/1.9 2.8/3.1 2.4/2.9 PIN Puncture g 631 912 873

    TABLE-US-00044 TABLE 37 Unit of Example 19. Five Layer Symmetric Film Property Measure Film Skin Composition 80% Styrolux S/20% Styrolux T Interlayer Composition 70% Kraton G1643/30% Adsyl 6C30F Core Composition 40% Adsyl 7415 XCP/26.7% Koattro DP8310M/33.3% Vistamaxx 3980FL TD Shrink  60° C. % 0 0 −0.2  65° C. % 4.7 4.2 4.7  70° C. % 16 17 16  75° C. % 31 29 32  80° C. % 40 40 40  85° C. % 47 48 48  90° C. % 53 54 54  95° C. % 59 59 58 100° C. % 64 64 61 105° C. % 68 68 66 Shrink Tension TD  80° C. grams 268 253 352  85° C. grams 310 298 320  90° C. grams 312 288 322  95° C. grams 232 287 287 100° C. grams 304 260 300 Natural Shrink TD  30° C. % 0 0 0  35° C. % 0.3 0.3 0.5  40° C. % 2.5 2.7 2.7  45° C. % 3.5 3 3

    [0202] Five layer films with a well-balanced and attractive combination of optical properties, shrink performance, low shrink tension, and stable natural shrink at typical storage temperatures were observed.

    Example 20

    [0203] Three additional films, identified as example 20 as a group, were fabricated by coextrusion, cast on a sequence of two chill rolls at 40° C., stretched in machine direction (MD) 1.2× at 85° C., then stretched in a tenter frame at 105° C., cooled and wound up as described above. The films all contained skin layers of 100% of Styrolux S and a core composition comprising fractional melt flow polypropylene-ethylene copolymer, polybutene-1 copolymer, and propylene-ethylene elastomeric copolymer. The intermediate layers are a blend of 70% Kraton G1643 and 30% Adsyl 6C30F terpolymer. Substituting a fractional melt flow rate propylene-ethylene copolymer in the film core in place of the higher melt flow rate terpolymer of example 17 provides improvements in extrusion stability and extrudate melt strength. Properties are provided in tables 38 and table 39 below.

    TABLE-US-00045 TABLE 38 Unit of Example 20. Five Layer Symmetric Film Property Measure Film Skin Composition 100% Styrolux S Interlayer Composition 70% Kraton G1643/30% Adsyl 6C30F Core Composition 40% Adsyl 7415 XCP/26.7% Koattro DP8310M/33.3% Vistamaxx 3980FL Yield in.sup.2/lb 20,313 17,201 16,901 Density g/cm.sup.3 0.953 0.958 0.946 Film Thickness (calculated) microns 36 43 44 Interlayer Thickness microns 3.7 3.5 4.7 (measured) Skin Thickness (measured) microns 7.9 10.0 10.5 Haze % 1.1 1.0 1.5 Gloss-IN gu >100 >100 >100 Gloss-OUT gu >100 >100 >100 Gurley Stiffness MD/TD 4.3/3.9 5.0/6.0 7.3/7.2 Flex StiffnessMD/TD g/in 1.7/1.9 2.8/3.1 2.4/2.9 PIN Puncture g 631 912 873

    TABLE-US-00046 TABLE 39 Unit of Example 20. Five Layer Film Property Measure Symmetric Film Skin Composition 100% Styrolux S Interlayer Composition 70% Kraton G1643/30% Adsyl 6C30F Core Composition 40% Adsyl 7415 XCP/26.7% Koattro DP8310M/33.3% Vistamaxx 3980FL TD Shrink  60° C. % 0 0 −0.2  65° C. % 4.7 4.2 4.7  70° C. % 16 17 16  75° C. % 31 29 32  80° C. % 40 40 40  85° C. % 47 48 48  90° C. % 53 54 54  95° C. % 59 59 58 100° C. % 64 64 61 105° C. % 68 68 66 Shrink Tension TD  80° C. grams 268 253 352  85° C. grams 310 298 320  90° C. grams 312 288 322  95° C. grams 232 287 287 100° C. grams 304 260 300 Natural Shrink TD  30° C. % 0 0 0  35° C. % 0.3 0.3 0.5  40° C. % 2.5 2.7 2.7  45° C. % 3.5 3 3

    [0204] Five layer films with a well-balanced and attractive combination of optical properties, shrink performance, low shrink tension, and stable natural shrink at typical storage temperatures were observed.

    Example 21

    [0205] Three additional films, identified as example 21 as a group, were produced by coextrusion, cast on a sequence of two chill rolls at 40° C., stretched in machine direction (MD) 1.2× at 80° C., then stretched in a tenter frame at 108° C., cooled and wound up as described above. The films all contained skin layers with a combination of 80% Styrolux S and 20% Styrolux T and a core composition comprising a concentrate of 60% fractional melt flow polypropylene-ethylene copolymer and 40% Plastolyn R1140 hard resin, polybutene-1 copolymer, and propylene-ethylene elastomeric copolymer. The intermediate layers are a blend of 70% Kraton G1643 and 30% Adsyl 6C30F terpolymer. Properties are provided in tables 40 and table 41 below.

    TABLE-US-00047 TABLE 40 Unit of Example 21. Five Layer Film Property Measure Symmetric Film Skin Composition 80% Styrolux S/20% Styrolux T Interlayer Composition 70% Kraton G1643/30% Adsyl 6C30F Core Composition 40% (60% Adsyl 7415 XCP/40% Plastolyn R1140) Concentrate)/26.7% Koattro DP8310M/33.3% Vistamaxx 3980FL Yield in.sup.2/lb 13,639 12,717 12,271 Density g/cm.sup.3 0.947 0.935 0.944 Film Thickness (calculated) microns 54 59 61 Interlayer Thickness (measured) microns 5.3 4.7 4.8 Skin Thickness (measured) microns 8.5 11.1 10.7 Haze % 1.1 0.8 1.0 Gloss-IN gu >100 >100 >100 Gloss-OUT gu >100 >100 >100 Gurley Stiffness MD/TD 11.3/12.5 12.7/15.8 20.1/17.4 Flex StiffnessMD/TD g/in 5.0/5.7 5.3/6.3 6.4/7.2 PIN Puncture g 935 1052 1081

    TABLE-US-00048 TABLE 41 Unit of Film Property Measure Example 21. Five Layer Symmetric Film Skin Composition 80% Styrolux S/20% Styrolux T Interlayer Composition 70% Kraton G1643/30% Adsyl 6C30F Core Composition 40% (60% Adsyl 7415 XCP/40% Plastolyn R1140) Concentrate)/26.7% Koattro DP8310M/33.3% Vistamaxx 3980FL TD Shrink  60° C. % 0 −0.2 0  65° C. % 2.5 2.7 2.8  70° C. % 16 16 17  75° C. % 30 30 31  80° C. % 43 41 44  85° C. % 50 50 51  90° C. % 58 58 59  95° C. % 64 62 63 100° C. % 68 68 69 105° C. % 71 71 73 Shrink Tension TD  80° C. grams 267 273 264  85° C. grams 268 259 280  90° C. grams 273 276 293  95° C. grams 292 301 298 100° C. grams 294 308 298 Natural Shrink TD  30° C. % 0 0 0  35° C. % 0.5 0 0.3  40° C. % 2 2 2  45° C. % 2.5 2.5 2.5

    [0206] The introduction of hard resin in the core provides an enhancement of film properties, including stiffness, shrink performance, lower shrink tension, and natural shrink stability at the highest storage temperatures.

    Example 22

    [0207] Three additional films, identified as example 22 as a group, were produced by coextrusion, cast on a sequence of two chill rolls at 40° C., stretched in machine direction (MD) 1.2× at 80° C., then stretched in a tenter frame at 108° C., cooled and wound up as described above. The films all contained skin layers with a combination of 80% Styrolux S and 20% Styrolux T and a core composition comprising a concentrate of 60% fractional melt flow polypropylene-ethylene copolymer and 40% Plastolyn R1140 hard resin, fractional melt flow polypropylene-ethylene copolymer, polybutene-1 copolymer, and propylene-ethylene elastomeric copolymer. The intermediate layers are a blend of 70% Kraton G1643 and 30% Adsyl 6C30F terpolymer. Properties are provided in table 42 and table 43 below.

    TABLE-US-00049 TABLE 42 Unit of Film Property Measure Example 22. Five Layer Symmetric Film Skin Composition 80% Styrolux S/20% Styrolux T Interlayer Composition 70% Kraton G1643/30% Adsyl 6C30F Core Composition 30% (60% Adsyl 7415 XCP/40% Plastolyn R1140) Concentrate)/10% Adsyl 7415 XCP/26.7% Koattro DP8310M/33.3% Vistamaxx 3980FL Yield in.sup.2/lb 13,582 12,584 11,481 Density g/cm.sup.3 0.941 0.940 0.945 Film Thickness (calculated) microns 55 59 65 Interlayer Thickness (measured) microns 3.9 4.7 4.9 Skin Thickness (measured) microns 10.2 9.2 11.1 Haze % 1.0 0.7 1.1 Gloss-IN gu >100 >100 >100 Gloss-OUT gu >100 >100 >100 Gurley Stiffness MD/TD 12.9/13.4 12.9/17.6 18.7/26.4 Flex StiffnessMD/TD g/in 4.9/6.3 6.8/7.4 8.5/9.7 PIN Puncture g 878 1147 1151

    TABLE-US-00050 TABLE 43 Unit of Film Property Measure Example 22. Five Layer Symmetric Film Skin Composition 80% Styrolux S/20% Styrolux T Interlayer Composition 70% Kraton G1643/30% Adsyl 6C30F Core Composition 30% (60% Adsyl 7415 XCP/40% Plastolyn R1140) Concentrate)/10% Adsyl 7415 XCP/26.7% Koattro DP8310M/33.3% Vistamaxx 3980FL TD Shrink  60° C. % −0.8 −0.5 −0.7  65° C. % 2 2 2  70° C. % 15 15 14  75° C. % 29 27 29  80° C. % 40 38 40  85° C. % 48 45 48  90° C. % 54 52 55  95° C. % 60 61 61 100° C. % 67 67 68 105° C. % 71 70 70 Shrink Tension TD  80° C. grams 297 311 312  85° C. grams 313 326 311  90° C. grams 298 315 295  95° C. grams 305 303 324 100° C. grams 316 292 332 Natural Shrink TD  30° C. % 0 0 0  35° C. % 0 0.2 0.2  40° C. % 2 2 2  45° C. % 2.5 2 2

    [0208] Once again, the benefits of hard resin introduction to the core is illustrated by the excellent combination of optical properties, stiffness, shrink performance, and film dimensional stability under storage conditions.

    Example 23

    [0209] Three additional films, identified as example 23 as a group, were produced by coextrusion, cast on a sequence of two chill rolls at 35° C., stretched in machine direction (MD) 1.2× at 85° C., then stretched in a tenter frame at 96° C., cooled and wound up as described above. The films all contained skin layers with a combination of 80% Styrolux S and 20% Styrolux T and a core composition comprising polypropylene terpolymer, polybutene-1 copolymer, and propylene-ethylene elastomeric copolymer. The intermediate layers are a blend of 70% by weight Tuftec P2000 styrene-ethylene-co-butene-styrene block copolymer and 30% by weight Adsyl 6C30F propylene-ethylene-butene terpolymer. Properties are provided in tables 44 and table 45 below.

    TABLE-US-00051 TABLE 44 Unit of Film Property Measure Example 23. Five Layer Symmetric Film Skin Composition 80% Styrolux S/20% Styrolux T Interlayer Composition 70% Tuftec P2000/30% Adsyl 6C30F Core Composition 40% Adsyl 6C30F/26.7% Koattro DP8310M/33.3% Vistamaxx 3980FL Yield in.sup.2/lb 16,045 13,686 13,576 Density g/cm.sup.3 0.944 0.940 0.936 Film Thickness (calculated) microns 46 55 55 Interlayer Thickness (measured) microns 2.8 3.0 3.8 Skin Thickness (measured) microns 9.3 8.6 9.3 Haze % 1.3 1.2 1.2 Gloss-IN gu >100 >100 >100 Gloss-OUT gu >100 >100 >100 Gurley Stiffness MD/TD 8.1/8.3 10.7/12.2 11.8/13.1 Flex StiffnessMD/TD g/in 2.9/3.3 4.5/6.5 5.0/6.2 PIN Puncture g 1201 1256 1306

    TABLE-US-00052 TABLE 45 Unit of Film Property Measure Example 23. Five Layer Symmetric Film Skin Composition 80% Styrolux S/20% Styrolux T Interlayer Composition 70% Tuftec P2000/30% Adsyl 6C30F Core Composition 40% Adsyl 6C30F/26.7% Koattro DP8310M/33.3% Vistamaxx 3980FL TD Shrink  60° C. % 0 0 0  65° C. % 8 7 7  70° C. % 21 20 21  75° C. % 34 33 33  80° C. % 48 48 48  85° C. % 53 55 55  90° C. % 61 61 61  95° C. % 65 66 66 100° C. % 68 70 69 105° C. % 70 72 71 Shrink Tension TD  80° C. grams 482 530 525  85° C. grams 494 532 567  90° C. grams 514 554 552  95° C. grams 507 534 581 100° C. grams 476 541 600 Natural Shrink TD  30° C. % 0 0 0  35° C. % −0.5 −0.5 −0.5  40° C. % 3.5 3.5 3.5

    [0210] An excellent combination of optical properties, stiffness, shrink performance, and film dimensional stability under storage conditions was observed.

    [0211] In a seventh embodiment of the present invention a five layer shrink film includes a core layer, two intermediate adhesive layers, and opposed skin layers; said intermediate adhesive layers and skin layers being thinner than said core layer. In this embodiment the film structure is symmetric, with one or more styrene-butadiene block copolymers (diblock or triblock) as the opposing skin layers and intermediate layers consisting of blends of one or more polymers from the group consisting of styrene-ethylene-co-butene-styrene triblock copolymer, styrene-ethylene-co-propylene-styrene triblock copolymer, styrene-ethylene-co-butene diblock copolymer, styrene-ethylene-co-propylene diblock copolymer and at least one or more polypropylene terpolymer or copolymer. The core layer includes one or more styrene-butadiene triblock or diblock copolymers, one or more styrene-ethylene/butene-styrene triblock or styrene-ethylene/butene diblock copolymers therein, in combination with a propylene-ethylene-butene terpolymer or propylene-ethylene copolymer, a butene-ethylene copolymer and a propylene-based elastomeric polymer. This core layer composition is the result of simulating the addition of reclaim into the core at levels which create significant opacity to the film. Optionally, a TiO2 concentrate with an ethylene polymer based carrier is present to enhance the films opacity and whiteness. A representative film structure of this sixth embodiment including the optional components is shown below.

    [0212] Corona Treatment (optional)

    TABLE-US-00053 ~4-12 μm skin layer 80-100% (80% Styrolux S/20% Styrolux T SBC)  0-20% ((SEBS or SEP or SEPS)) 1.5-4.5 μm inter-layer  60-95% Kraton G SEBS or SEPS Block Copolymer  5-40% LYB 6C30F Terpolymer or Total 8573 Copolymer 30-45 μm core layer  20-35% LYB Adsyl 6C30F Terpolymer or Adsyl 7415 XCP  10-25% LYB Koattro DP8310M Polybutene-1  10-30% Vistamaxx 3980FL or Versify 3000 copolymer  10-60% Reclaim (Terpolymer, butene- ethylene copolymer, propylene-based elastomer, styrene ethylene/butene-styrene block copolymer, styrene-butadiene block copolymer)  0-10% Polyethylene based TiO2 concentrate 1.5-4.5 μm inter-layer  60-95% Kraton G SEBS or SEPS Block Copolymer  5-40% LYB 6C30F Terpolymer or Total 8573 Copolymer ~4-12 μm skin layer 80-100% (80% Styrolux S/20% Styrolux T SBC)  0-20% ((SEBS or SEP or SEPS))

    [0213] Corona Treatment (optional)

    Example 24

    [0214] Three additional films, identified as example 24 as a group, were produced by coextrusion, cast on a sequence of two chill rolls at 40° C., stretched in machine direction (MD) 1.2× at 80° C., then stretched in a tenter frame at 108° C., cooled and wound up as described above. The films all contained skin layers with a combination of 80% Styrolux S and 20% Styrolux T and the core layer includes one or more styrene-butadiene triblock or diblock copolymers, one or more styrene-ethylene-co-butene-styrene triblock or styrene-ethylene-co-butene diblock copolymers therein, in combination with a propylene-ethylene-butene terpolymer or propylene-ethylene copolymer, a butene-ethylene copolymer and a propylene-based elastomeric polymer. This core layer composition is the result of incorporating reclaim into the core at levels which create significant opacity to the film. The intermediate layers are a blend of 70% Kraton G1643 and 30% Adsyl 6C30F. Properties are provided in tables 46 and table 47 below.

    TABLE-US-00054 TABLE 46 Unit of Film Property Measure Example 24. Five Layer Symmetric Film Skin Composition 80% Styrolux S/20% Styrolux T Interlayer Composition 70% Kraton G1643/30% Adsyl 6C30F Core Composition 31% Adsyl 6C30F/18% Koattro DP8310M/24.3% Vistamaxx 3980FL/ 17.3% Styrolux S/4.4% Styrolux T/5% Kraton G1643 Yield in.sup.2/lb 13,089 12,531 12,027 Density g/cm.sup.3 0.949 0.954 0.953 Film Thickness (calculated) microns 57 59 61 Interlayer Thickness (measured) microns 4.2 4.4 3.3 Skin Thickness (measured) microns 8.7 11.5 9.5 Opacity % 22 21 22 Opacity after shrink at 95 C. % 27 27 27 Gloss-IN gu 89 88 87 Gloss-OUT gu 88 89 88 Gurley Stiffness MD/TD 15.0/15.1 15.8/15.5 14.3/15.8 Flex StiffnessMD/TD g/in 6.5/6.8 5.4/6.8 6.9/7.6 PIN Puncture g 1123 1167 1197

    TABLE-US-00055 TABLE 47 Unit of Film Property Measure Example 24. Five Layer Symmetric Film Skin Composition 80% Styrolux S/20% Styrolux T Interlayer Composition 70% Kraton G1643/30% Adsyl 6C30F Core Composition 31% Adsyl 6C30F/18% Koattro DP8310M/24.3% Vistamaxx 3980FL/ 17.3% Styrolux S/4.4% Styrolux T/5% Kraton G1643 TD Shrink  60° C. % −0.8 −0.5 −1  65° C. % 1.3 1 1  70° C. % 12 12 12  75° C. % 24 22 24  80° C. % 36 34 34  85° C. % 44 44 43  90° C. % 50 52 49  95° C. % 59 59 57 100° C. % 64 66 64 105° C. % 70 71 70 Shrink Tension TD  80° C. grams 232 226 224  85° C. grams 231 220 228  90° C. grams 219 219 230  95° C. grams 210 216 218 100° C. grams 215 223 243 Natural Shrink TD  30° C. % 0 0 0  35° C. % 0 0 0  40° C. % 1.5 1.5 1.5  45° C. % 1.5 1.5 1.5

    [0215] The above example 24 illustrates high levels of reclaim can be incorporated into the film core while maintaining film floatability (density less than 1.0 g/cm.sup.3). Reclaim is compatible in the core structures and does not detrimentally impact the ability to produce a high quality TD oriented film with a good balance of properties. As illustrated in the next example 25, this provides an excellent base film for the further introduction of an opacifying agent (TiO.sub.2) in sufficient quantity to produce a solid white film while maintaining a density below 1 g/cm.sup.3.

    Example 25

    [0216] Three additional films, identified as example 25 as a group, were produced by coextrusion, cast on a sequence of two chill rolls at 40° C., stretched in machine direction (MD) 1.2× at 80° C., then stretched in a tenter frame at 108° C., cooled and wound up as described above. The films all contained skin layers with a combination of 80% Styrolux S and 20% Styrolux T and the core layer includes one or more styrene-butadiene triblock or diblock copolymers, one or more styrene-ethylene-co-butene-styrene triblock or styrene-ethylene-co-butene diblock copolymers therein, in combination with a propylene-ethylene-butene terpolymer or propylene-ethylene copolymer, a butene-ethylene copolymer, a propylene-based elastomeric polymer, and a 70% TiO.sub.2 concentrate in a LDPE carrier. This core layer composition is the result of simulating the incorporating of reclaim into the core at levels which create significant opacity to the film. Opacity is further enhanced through the introduction of TiO.sub.2 with an ethylene polymer carrier which does not interfere with the shrink performance of the film. The intermediate layers are a blend of 70% Kraton G1643 and 30% Adsyl 6C30F. Properties are provided in tables 48 and table 49 below.

    TABLE-US-00056 TABLE 48 Unit of Film Property Measure Example 25. Five Layer Symmetric Film Skin Composition 80% Styrolux S/20% Styrolux T Interlayer Composition 70% Kraton G1643/30% Adsyl 6C30F Core Composition 30% Adsyl 6C30F/17% Koattro DP8310M/21.3% Vistamaxx 3980FL/ 17.3% Styrolux S/4.4% Styrolux T/5% Kraton G1643/5% POLYBATCH White 8000 EC Yield in.sup.2/lb 12,789 12,564 12,444 Density g/cm.sup.3 0.972 0.974 0.968 Film Thickness (calculated) microns 56 57 58 Interlayer Thickness (measured) microns 4.2 4.9 4.0 Skin Thickness (measured) microns 10.1 9.8 9.2 Opacity as produced % 63 62 61 Opacity after shrink at 95 C. % 67 66 66 Gloss-IN gu 65 65 63 Gloss-OUT gu 60 65 66 Gurley Stiffness MD/TD 15.1/16.1 14.8/14.9 14.2/18.0 Flex Stiffness MD/TD g/in 6.5 /7.6 5.9/5.9 6.2/6.7 PIN Puncture g 1137 1219 1101

    TABLE-US-00057 TABLE 49 Unit of Film Property Measure Example 25. Five Layer Symmetric Film Skin Composition 80% Styrolux S/20% Styrolux T Interlayer Composition 70% Kraton G1643/30% Adsyl 6C30F Core Composition 30% Adsyl 6C30F/17% Koattro DP8310M/21.3% Vistamaxx 3980FL/ 17.3% Styrolux S/4.4% Styrolux T/5% Kraton G1643/5% POLYBATCH White 8000 EC TD Shrink  60° C. % −1 −1 −1  65° C. % 1 1 1  70° C. % 12 12 12  75° C. % 23 23 24  80° C. % 34 35 37  85° C. % 43 44 45  90° C. % 49 50 51  95° C. % 56 58 58 100° C. % 64 64 64 105° C. % 70 71 70 Shrink Tension TD  80° C. grams 233 240 225  85° C. grams 217 223 240  90° C. grams 221 229 227  95° C. grams 218 218 225 100° C. grams 216 230 205 Natural Shrink TD  30° C. % −0.3 −0.2 0  35° C. % −0.2 −0.2 0  40° C. % 1.5 1.3 1.5  45° C. % 1.5 1.5 1.5

    [0217] The ability to incorporate high level of reclaim into the core of the film and the introduction of low levels of opacifying agent while maintaining a density less than 1.0 g/cm.sup.3 is shown in the above example 25. An overall excellent balance of opacity, stiffness, shrink performance under steam tunnel conditions, and storage stability is demonstrated.

    [0218] The introduction of reclaim and an opacifying agent into the core while maintaining a density below 1 g/cm.sup.3 provides the ability to produce a floatable film which can be separated from non-floatable containers while creating an effective UV and Visible light barrier in applications, such as dairy products, where the container contents are detrimentally affected over time by light exposure in the wavelength range of 200-750 nm. This is illustrated in FIG. 4 which compares the light blocking performance (% Transmission) of optically clear film of Example 15, Example 24, and Example 25. Exceptional light blocking performance (below 5% transmission in the range of 200-750 nm wavelength) with the incorporation of film reclaim and the introduction of low levels of opacifying agents is demonstrated.

    [0219] The relationship between film thickness and MD flex stiffness for the PS skin floatable films of this invention is illustrated and compared to commercially available non-floatable PETG shrink film materials having a densities greater than 1 g/cm.sup.3 (densities=1.27-1.31 g/cm.sup.3) in FIG. 5 below. In addition to an overall exponential dependence on film thickness, the blend ratio of the two components incorporated into the PS skins of the floatable films has a very significant influence on the MD flexural stiffness of the structure. A stiffness/thickness match of the commercial non-floatable PETG shrink film is achievable while maintaining a density less than 1 g/cm.sup.3 for the PS skin floatable films of this invention.

    [0220] Because of the substantial difference in density between the floatable films with PS skins in comparison to the non-floatable PETG films, on the basis of equivalent yield or coverage (in.sup.2/lb), the floatable film structures provide a substantially higher specific stiffness (stiffness to weight or yield ratio) relative to the non-floatable PETG film, as illustrated in FIG. 6, which compares flex stiffness to film yield. Here again, the blend ratio of the two component incorporated into the PS skin has a very significant influence on the magnitude of stiffness to yield ratio.

    [0221] In an eighth embodiment of the present invention, three component organic solvent blends usable to form continuous welded seams in accordance with the broadest aspects of this invention have been identified. The blends are based on the combination of one component selected from the class of naturally occurring organic materials known as terpenes, at least one or more components selected from the group consisting of a straight chain ether, a branched chain ether, a cyclic ether, a substituted cyclic ether, a cyclic diether, a substituted cyclic diether, and at least one or more components selected from the group consisting of a straight chain ketone, a branched chain ketone, a cyclic ketone, and a substituted cyclic ketone.

    [0222] Specific combinations and ratios of one or more terpenes in combination with one and/or the other of cyclic ketones and cyclic ethers have been found to be very effective seaming solvents for polyolefin based shrink film with at least one skin layer comprising at least one styrene copolymer. Preferred solvent blends are based on a-Pinene as the terpene component. Five layer film of example 15, described in Table 28 and 29 above, was hand seamed into shrink sleeves using a laboratory seamer (available from Ryback & Ryback, Inc., Monroe, N.C.). Several solvent blends based on combinations of a-Pinene, Cyclohexanone, and 1,3-Dioxolane were evaluated. Seam width for all films was kept within a range of 0.2-0.3 inches (5-7.5 mm). The resulting sleeves were aged at room temperature for several hours prior to T-peel testing on a MTS Q-Test/1L tensile tester. Results are described in Table 50 below.

    TABLE-US-00058 TABLE 50 Solvent Recipe T-Peel (g/25 mm) Lap Shear (Vol %) Peak Peel (lb-f) 50% α-Pinene 756 654 18 40% Cyclohexanone 10% 1,3-Dioxolane 40% α-Pinene 689 570 22 20% Cyclohexanone 40% 1,3-Dioxolane 40% α-Pinene 798 639 20 30% Cyclohexanone 30% 1,3-Dioxolane 40% α-Pinene 617 492 21 40% Cyclohexanone 20% 1,3-Dioxolane 40% α-Pinene 750 627 19 50% Cyclohexanone 10% 1,3-Dioxolane 60% α-Pinene 720 668 17 30% Cyclohexanone 10% 1,3-Dioxolane 50% α-Pinene 663 624 18 30% Cyclohexanone 20% 1,3-Dioxolane

    [0223] Consistent high peel strength (Peak and Peel) was observed with the solvent blends selected, indicating the films would be suitable for shrink sleeve applications and that a number of options exist for solvent seaming of these floatable films.

    [0224] Additional seaming tests were conducted on a series of films described in embodiments six and seven. A solvent blend of 40 vol % α-Pinene, 30 vol % Cyclohexanone, and 30 vol % 1,3-Dioxolane was used for these seaming evaluations. T-peel results are described in Table 51 below:

    TABLE-US-00059 TABLE 51 Solvent Recipe Film T-Peel (g/25 mm) (Vol %) Designation Peak Peel 40% α-Pinene Example 18 1134 1025 30% Cyclohexanone Example 19 838 787 30% 1,3-Dioxolane Example 21 803 724 Example 22 998 860 Example 23 1304 857 Example 24 645 554 Example 25 725 611

    [0225] Exceptional high peel strength (Peak and Peel) was observed with the solvent blend selected, indicating these films would be suitable for shrink sleeve applications.

    [0226] In the most preferred embodiments of this invention, the film, without a voiding or whitening agent therein, is essentially uniaxially oriented. If a voiding agent is included in the structure to provide opacity, it may be desirable to biaxially orient the film to aid in creating voids, and thereby reducing the density of the film.

    [0227] In general, an opaque shrink film in accordance with this invention provided with a voiding agent have a density less than 1 g/cm.sup.3. If a non-voiding, opacifying agent is used in one or more layers thereof, the film density may be greater than or less than 1 g/cm.sup.3, dependent upon the concentration of opacifying agent incorporate. Non-voiding opacifying agent and voiding agents are well known in the art. By way of example, a non-voiding opacifying agent can include TiO.sub.2 and voiding agents according to this invention include PBT (polybutylene terephthalate) and CaCO.sub.3. This invention is not limited to the use of any specific non-voiding opacifying agent and/or voiding agent; the particular agent(s) selected being within the general skill of the art.

    [0228] Although the present invention has been described in connection with preferred embodiments thereof, it will be appreciated by those skilled in the art that additions, modifications, substitutions, and deletions not specifically described may be made without departing from the spirit and scope of the invention defined in the appended claim.