Process for producing foam beads using a modified ethylene-based polymer

Abstract

The present disclosure provides a process. The process includes (i) forming a composition containing a peroxide-modified ethylene-based polymer selected from the group consisting of a peroxide-modified ethylene/a-olefin multi-block copolymer, a peroxide-modified low density polyethylene, and combinations thereof; (ii) contacting the composition with a blowing agent to form a foam composition; and (iii) forming foam beads comprising the foam composition. The present disclosure also provides a foam bead produced by said process.

Claims

1. A process comprising: (A) forming a composition by melt blending a blend consisting of (1) from 10 wt % to 40 wt % of (i) a peroxide-modified ethylene/α-olefin multi-block copolymer with a base ethylene/α-olefin multi-block copolymer consisting of ethylene and C.sub.4-C.sub.8 α-olefin comonomer having a melting point from 115° C. to 125° C. and a density from 0.865 g/cc to 0.88 g/cc, modified with 0.10 wt % to 0.12 wt % peroxide, and (ii) an optional additive selected from the group consisting of nucleators, processing aids, lubricants, stabilizers, antioxidants, foaming aids, surfactants, flow aids, viscosity control agents, coloring agents, copper inhibitors, inorganic fillers, and combinations thereof, and (2) from 90 wt % to 60 wt % of an ethylene/α-olefin multi-block copolymer consisting of ethylene and C.sub.4-C.sub.8 α-olefin comonomer having a melting point from 115° C. to 125° C. and a density from 0.865 g/cc to 0.88 g/cc; (B) contacting the composition with a blowing agent to form a foam composition; and (C) forming foam beads comprising the foam composition, the foam beads having (a) a melt strength from 9 cN to 10 cN, (b) a gel content of 0%, (c) a foam density from 0.230 g/cc to 0.290 g/cc, (d) a melt index from 0.3 g/10 min to 0.4 g/10 min, (e) a low shear viscosity (at 1 rad/second) from 38,000 Pa.Math.s to 48,000 Pa.Math.s, and (f) a high shear viscosity (at 100 rad/second) from 3200 Pa.Math.s to 3400 Pa.Math.s.

2. The process of claim 1 comprising contacting the composition with the blowing agent at a temperature of from 100° C. to 130° C.

3. The process of claim 1 wherein the blowing agent is a physical blowing agent.

4. A process comprising: (A) forming a composition by melt blending a blend consisting of (1) from 10 wt % to 20 wt % of (i) a peroxide-modified low density polyethylene homopolymer with a base low density polyethylene homopolymer having a melting point from 105° C. to 110° C. and a density from 0.915 g/cc to 0.920 g/cc, modified with from 0.02 wt % to 0.04 wt % peroxide, and (ii) an optional additive selected from the group consisting of nucleators, processing aids, lubricants, stabilizers, antioxidants, foaming aids, surfactants, flow aids, viscosity control agents, coloring agents, copper inhibitors, inorganic fillers, and combinations thereof, and (2) from 90 wt % to 80 wt % of an ethylene/α-olefin multi-block copolymer having a melting point from 115° C. to 125° C. and a density from 0.865 g/cc to 0.88 g/cc, (B) contacting the composition with a blowing agent to form a foam composition; and (C) forming foam beads comprising the foam composition, the foam beads having (a) a melt strength from 14.0 cN to 21.0 cN, (b) a gel content of 0%, (c) a foam density from 0.190 g/cc to 0.230 g/cc, (d) a melt index from 0.40 g/10 min to 0.45 g/10 min, (e) a low shear viscosity (at 1 rad/second) from 31,000 Pa.Math.s to 37,000 Pa.Math.s, and (f) a high shear viscosity (at 100 rad/second) from 2600 Pa.Math.s to 3000 Pa.Math.s.

5. A foam bead comprising: a composition consisting of (1) from 10 wt % to 40 wt % of (i) a peroxide-modified ethylene/α-olefin multi-block copolymer with a base ethylene/α-olefin multi-block copolymer consisting of ethylene and C.sub.4-C.sub.8 α-olefin comonomer having a melting point from 115° C. to 125° C. and a density from 0.865 g/cc to 0.88 g/cc, modified with from 0.10 wt % to 0.12 wt % peroxide, and (ii) optional additive selected from the group consisting of nucleators, processing aids, lubricants, stabilizers, antioxidants, foaming aids, surfactants, flow aids, viscosity control agents, coloring agents, copper inhibitors, inorganic fillers, and combinations thereof, and (2) from 90 wt % to 60 wt % of an ethylene/α-olefin multi-block copolymer consisting of ethylene and C.sub.4-C.sub.8 α-olefin comonomer having a melting point from 115° C. to 125° C. and a density from 0.865 g/cc to 0.88 g/cc; the foam beads have (a) a melt strength from 9 cN to 10 cN; (b) a gel content of 0%; and (c) a foam density from 0.230 g/cc to 0.290 g/cc, (d) a melt index from 0.3 g/10 min to 0.4 g/10 min, (e) a low shear viscosity (at 1 rad/second) from 38,000 Pa.Math.s to 48,000 Pa.Math.s, and (f) a high shear viscosity (at 100 rad/second) from 3200 Pa.Math.s to 3400 Pa.Math.s.

6. A foam bead comprising: a composition consisting of (1) from 10 wt % to 20 wt % of (i) a peroxide-modified low density polyethylene homopolymer with a base low density polyethylene homopolymer having a melting point from 105° C. to 110° C., and a density from 0.915 g/cc to 0.920 g/cc, modified with from 0.02 wt % to 0.04 wt % peroxide and (ii) optional additive selected from the group consisting of nucleators, processing aids, lubricants, stabilizers, antioxidants, foaming aids, surfactants, flow aids, viscosity control agents, coloring agents, copper inhibitors, inorganic fillers, and combinations thereof, and (2) from 90 wt % to 80 wt % of an ethylene/α-olefin multi-block copolymer consisting of ethylene and C.sub.4-C.sub.8 α-olefin comonomer and having a melting point from 115° C. to 125° C. and a density from 0.865 g/cc to 0.88 g/cc; and the foam beads have (a) a melt strength from 14.0 cN to 21.0 cN, (b) a gel content of 0%, (c) a foam density from 0.190 g/cc to 0.230 g/cc, (d) a melt index from 0.40 g/10 min to 0.45 g/10 min, (e) a low shear viscosity (at 1 rad/second) from 31,000 Pa.Math.s to 37,000 Pa.Math.s, and (f) a high shear viscosity (at 100 rad/second) from 2600 Pa.Math.s to 3000 Pa.Math.s.

Description

DETAILED DESCRIPTION

(1) The present disclosure provides a process. The process includes (i) forming a composition containing a peroxide-modified ethylene-based polymer selected from a peroxide-modified ethylene/α-olefin multi-block copolymer, a peroxide-modified low density polyethylene, and combinations thereof; (ii) contacting the composition with a blowing agent to form a foam composition; and (iii) forming foam beads containing the foam composition.

(2) i. Forming a Composition

(3) The process includes the step of forming a composition containing (A) a peroxide-modified ethylene-based polymer selected from a peroxide-modified ethylene/α-olefin multi-block copolymer, a peroxide-modified low density polyethylene, and combinations thereof; (B) optionally, an ethylene/α-olefin multi-block copolymer; and (C) optionally, an additive.

(4) A. Peroxide-Modified Ethylene-Based Polymer

(5) The present composition includes a peroxide-modified ethylene-based polymer selected from a peroxide-modified ethylene/α-olefin multi-block copolymer, a peroxide-modified low density polyethylene, and combinations thereof. A “peroxide-modified ethylene-based polymer” is an ethylene-based polymer that has been melt blended with a peroxide such that the peroxide acts as a rheology modifying agent in such a way (i) that the degree of long chain branching (LCB) in the peroxide-modified ethylene-based polymer is greater than the degree of LCB in the base ethylene-based polymer prior to peroxide modification, but (ii) the addition of peroxide does not induce crosslinking, as evidenced by the peroxide-modified ethylene-based polymer having a gel content of 0%. In other words, the peroxide-modified ethylene-based polymer is a thermoplastic that is still melt processable (and it not thermoset). A nonlimiting example of a suitable melt blending process is an extrusion process. The base ethylene-based polymer is an ethylene/α-olefin multi-block copolymer or a LDPE, as described in detail below.

(6) Nonlimiting examples of suitable peroxides include bis(t-butylperoxy) diisopropylbenzene (BIBP), dialkyl peroxide, and combinations thereof. Nonlimiting examples of suitable dialkyl peroxides include dicumyl peroxide; di-t-butyl peroxide; t-butyl cumyl peroxide; 2,5-dimethyl-2,5-di(tert-butylperoxy)-hexane; 2,5-dimethyl-2,5-di(tert-amylperoxy)-hexane; 2,5-dimethyl-2,5-di(tert-butylperoxy)hexyne-3,2,5-dimethyl-2,5-di(tert-amylpero-xy)hexyne-3; α,α-di[(tert-butylperoxy)-isopropyl]-benzene; di-t-amyl peroxide (DTAP); 1,3,5-tri-[(tert-butylperoxy)-isopropyl]benzene; 1,3-dimethyl-3-(tert-butylperoxy)butanol; 1,3-dimethyl-3-(tert-amylperoxy) butanol; and combinations thereof. In an embodiment, the peroxide is BIBP.

(7) In an embodiment, the peroxide-modified ethylene-based polymer is formed by melt blending from 99.85 wt %, or 99.88 wt % or 99.90 wt % to 99.95 wt %, or 99.96 wt %, or 99.99 wt % base ethylene-based polymer and from 0.01 wt %, or 0.04 wt %, or 0.05 wt % to 0.10 wt %, or 0.12 wt %, or 0.15 wt % peroxide, based on the combined amount of base ethylene-based polymer and peroxide. Nonlimiting examples of suitable melt blending processes include (i) extrusion and (ii) mixing at a temperature at or above the melting temperature of the base ethylene-based polymer.

(8) In an embodiment, all, or substantially all, of the peroxide reacts with the base ethylene-based polymer during melt blending at a temperature higher than the peroxide's decomposition temperature (1 minute half-life) such that the peroxide-modified ethylene-based polymer contains 0 wt %, or from 0 wt % to less than 0.01 wt % peroxide.

(9) 1. Peroxide-Modified Ethylene/α-Olefin Multi-Block Copolymer

(10) In an embodiment, the composition contains a peroxide-modified ethylene/α-olefin multi-block copolymer. A “peroxide-modified ethylene/α-olefin multi-block copolymer” is an ethylene/α-olefin multi-block copolymer that has been melt blended with a peroxide such that the peroxide acts as a rheology modifying agent in such a way (i) that the degree of LCB in the peroxide-modified ethylene/α-olefin multi-block copolymer is greater than the degree of LCB in the base ethylene/α-olefin multi-block copolymer prior to peroxide modification, but (ii) the addition of peroxide does not induce crosslinking, as evidenced by the peroxide-modified ethylene/α-olefin multi-block copolymer having a gel content of 0%.

(11) The base ethylene/α-olefin multi-block copolymer is an ethylene/α-olefin multi-block copolymer. The term “ethylene/α-olefin multi-block copolymer” refers to an ethylene/C4-C8 α-olefin multi-block copolymer consisting of ethylene and one copolymerizable C4-C8 α-olefin comonomer in polymerized form (and optional additives), the polymer characterized by multiple blocks or segments of two polymerized monomer units differing in chemical or physical properties, the blocks joined (or covalently bonded) in a linear manner, that is, a polymer comprising chemically differentiated units which are joined end-to-end with respect to polymerized ethylenic functionality. Ethylene/α-olefin multi-block copolymer includes block copolymer with two blocks (di-block) and more than two blocks (multi-block). The C4-C8 α-olefin is selected from butene, hexene, and octene. The ethylene/α-olefin multi-block copolymer is void of, or otherwise excludes, styrene (i.e., is styrene-free), and/or vinyl aromatic monomer, and/or conjugated diene. When referring to amounts of “ethylene” or “comonomer” in the copolymer, it is understood that this refers to polymerized units thereof. In some embodiments, the ethylene/α-olefin multi-block copolymer can be represented by the following formula: (AB)n; where n is at least 1, preferably an integer greater than 1, such as 2, 3, 4, 5, 10, 15, 20, 30, 40, 50, 60, 70, 80, 90, 100, or higher, “A” represents a hard block or segment, and “B” represents a soft block or segment. The As and Bs are linked, or covalently bonded, in a substantially linear fashion, or in a linear manner, as opposed to a substantially branched or substantially star-shaped fashion. In other embodiments, A blocks and B blocks are randomly distributed along the polymer chain. In other words, the block copolymers usually do not have a structure as follows: AAA-AA-BBB-BB. In an embodiment, the ethylene/α-olefin multi-block copolymer does not have a third type of block, which comprises different comonomer(s). In another embodiment, each of block A and block B has monomers or comonomers substantially randomly distributed within the block. In other words, neither block A nor block B comprises two or more sub-segments (or sub-blocks) of distinct composition, such as a tip segment, which has a substantially different composition than the rest of the block.

(12) Preferably, ethylene comprises the majority mole fraction of the whole ethylene/α-olefin multi-block copolymer, i.e., ethylene comprises at least 50 wt % of the whole ethylene/α-olefin multi-block copolymer. More preferably, ethylene comprises at least 60 wt %, at least 70 wt %, or at least 80 wt %, with the substantial remainder of the whole ethylene/α-olefin multi-block copolymer comprising the C.sub.4-C.sub.8 α-olefin comonomer. In an embodiment, the ethylene/α-olefin multi-block copolymer contains 50 wt % to 90 wt % ethylene, or 60 wt % to 85 wt % ethylene, or 65 wt % to 80 wt % ethylene. For many ethylene/octene multi-block copolymers, the composition comprises an ethylene content greater than 80 wt % of the whole ethylene/octene multi-block copolymer and an octene content of from 10 wt % to 15 wt %, or from 15 wt % to 20 wt % of the whole multi-block copolymer.

(13) The ethylene/α-olefin multi-block copolymer includes various amounts of “hard” segments and “soft” segments. “Hard” segments are blocks of polymerized units in which ethylene is present in an amount greater than 90 wt %, or 95 wt %, or greater than 95 wt %, or greater than 98 wt %, based on the weight of the polymer, up to 100 wt %. In other words, the comonomer content (content of monomers other than ethylene) in the hard segments is less than 10 wt %, or 5 wt %, or less than 5 wt %, or less than 2 wt %, based on the weight of the polymer, and can be as low as zero. In some embodiments, the hard segments include all, or substantially all, units derived from ethylene. “Soft” segments are blocks of polymerized units in which the comonomer content (content of monomers other than ethylene) is greater than 5 wt %, or greater than 8 wt %, greater than 10 wt %, or greater than 15 wt %, based on the weight of the polymer. In an embodiment, the comonomer content in the soft segments is greater than 20 wt %, greater than 25 wt %, greater than 30 wt %, greater than 35 wt %, greater than 40 wt %, greater than 45 wt %, greater than 50 wt %, or greater than 60 wt % and can be up to 100 wt %.

(14) The soft segments can be present in an ethylene/α-olefin multi-block copolymer from 1 wt % to 99 wt % of the total weight of the ethylene/α-olefin multi-block copolymer, or from 5 wt % to 95 wt %, from 10 wt % to 90 wt %, from 15 wt % to 85 wt %, from 20 wt % to 80 wt %, from 25 wt % to 75 wt %, from 30 wt % to 70 wt %, from 35 wt % to 65 wt %, from 40 wt % to 60 wt %, or from 45 wt % to 55 wt % of the total weight of the ethylene/α-olefin multi-block copolymer. Conversely, the hard segments can be present in similar ranges. The soft segment weight percentage and the hard segment weight percentage can be calculated based on data obtained from DSC or NMR. Such methods and calculations are disclosed in, for example, U.S. Pat. No. 7,608,668, entitled “Ethylene/α-Olefin Block Inter-Polymers,” filed on Mar. 15, 2006, in the name of Colin L. P. Shan, Lonnie Hazlitt, et. al. and assigned to Dow Global Technologies Inc., the disclosure of which is incorporated by reference herein in its entirety. In particular, hard and soft segment weight percentages and comonomer content may be determined as described in column 57 to column 63 of U.S. Pat. No. 7,608,668.

(15) The ethylene/α-olefin multi-block copolymer comprises two or more chemically distinct regions or segments (referred to as “blocks”) joined (or covalently bonded) in a linear manner, that is, it contains chemically differentiated units which are joined end-to-end with respect to polymerized ethylenic functionality, rather than in pendent or grafted fashion. In an embodiment, the blocks differ in the amount or type of incorporated comonomer, density, amount of crystallinity, crystallite size attributable to a polymer of such composition, type or degree of tacticity (isotactic or syndiotactic), regio-regularity or regio-irregularity, amount of branching (including long chain branching or hyper-branching), homogeneity or any other chemical or physical property. Compared to block interpolymers of the prior art, including interpolymers produced by sequential monomer addition, fluxional catalysts, or anionic polymerization techniques, the present ethylene/α-olefin multi-block copolymer is characterized by unique distributions of both polymer polydispersity (PDI or Mw/Mn or MWD), polydisperse block length distribution, and/or polydisperse block number distribution, due, in an embodiment, to the effect of the shuttling agent(s) in combination with multiple catalysts used in their preparation.

(16) In an embodiment, the ethylene/α-olefin multi-block copolymer is produced in a continuous process and possesses a polydispersity index (Mw/Mn) from 1.7 to 3.5, or from 1.8 to 3, or from 1.8 to 2.5, or from 1.8 to 2.2. When produced in a batch or semi-batch process, the ethylene/α-olefin multi-block copolymer possesses Mw/Mn from 1.0 to 3.5, or from 1.3 to 3, or from 1.4 to 2.5, or from 1.4 to 2.

(17) In addition, the ethylene/α-olefin multi-block copolymer possesses a PDI (or Mw/Mn) fitting a Schultz-Flory distribution rather than a Poisson distribution. The present ethylene/α-olefin multi-block copolymer has both a polydisperse block distribution as well as a polydisperse distribution of block sizes. This results in the formation of polymer products having improved and distinguishable physical properties. The theoretical benefits of a polydisperse block distribution have been previously modeled and discussed in Potemkin, Physical Review E (1998) 57 (6), pp. 6902-6912, and Dobrynin, J. Chem. Phys. (1997) 107 (21), pp 9234-9238.

(18) In an embodiment, the present ethylene/α-olefin multi-block copolymer possesses a most probable distribution of block lengths.

(19) In a further embodiment, the ethylene/α-olefin multi-block copolymer of the present disclosure, especially those made in a continuous, solution polymerization reactor, possess a most probable distribution of block lengths. In one embodiment of this disclosure, ethylene/α-olefin multi-block copolymers are defined as having:

(20) (A) Mw/Mn from about 1.7 to about 3.5, at least one melting point, Tm, in degrees Celsius, and a density, d, in grams/cubic centimeter, where in the numerical values of Tm and d correspond to the relationship:
Tm>−2002.9+4538.5(d)−2422.2(d).sup.2, and/or

(21) (B) Mw/Mn from about 1.7 to about 3.5, and is characterized by a heat of fusion, ΔH in J/g, and a delta quantity, ΔT, in degrees Celsius defined as the temperature difference between the tallest DSC peak and the tallest Crystallization Analysis Fractionation (“CRYSTAF”) peak, wherein the numerical values of ΔT and ΔH have the following relationships:
ΔT>−0.1299 ΔH+62.81 for ΔH greater than zero and up to 130 J/g
ΔT≥48° C. for ΔH greater than 130 J/g
wherein the CRYSTAF peak is determined using at least 5 percent of the cumulative polymer, and if less than 5 percent of the polymer has an identifiable CRYSTAF peak, then the CRYSTAF temperature is 30° C.; and/or

(22) (C) elastic recovery, Re, in percent at 300 percent strain and 1 cycle measured with a compression-molded film of the ethylene/α-olefin interpolymer, and has a density, d, in grams/cubic centimeter, wherein the numerical values of Re and d satisfy the following relationship when ethylene/α-olefin interpolymer is substantially free of crosslinked phase:
Re>1481−1629(d); and/or

(23) (D) has a molecular fraction which elutes between 40° C. and 130° C. when fractionated using TREF, characterized in that the fraction has a molar comonomer content of at least 5 percent higher than that of a comparable random ethylene interpolymer fraction eluting between the same temperatures, wherein said comparable random ethylene interpolymer has the same comonomer(s) and has a melt index, density and molar comonomer content (based on the whole polymer) within 10 percent of that of the ethylene/α-olefin interpolymer; and/or

(24) (E) has a storage modulus at 25° C., G′(25° C.), and a storage modulus at 100° C., G′(100° C.), wherein the ratio of G′(25° C.) to G′(100° C.) is in the range of 1:1 to 9:1.

(25) The ethylene/α-olefin multi-block copolymer may also have:

(26) (F) a molecular fraction which elutes between 40° C. and 130° C. when fractionated using TREF, characterized in that the fraction has a block index of at least 0.5 and up to 1 and a molecular weight distribution, Mw/Mn, greater than 1.3; and/or

(27) (G) average block index greater than zero and up to 1.0 and a molecular weight distribution, Mw/Mn greater than 1.3.

(28) It is understood that the ethylene/α-olefin multi-block copolymer may have one, some, all, or any combination of properties (A)-(G). Block Index can be determined as described in detail in U.S. Pat. No. 7,608,668 herein incorporated by reference for that purpose. Analytical methods for determining properties (A) through (G) are disclosed in, for example, U.S. Pat. No. 7,608,668, col. 31 line 26 through col. 35 line 44, which is herein incorporated by reference for that purpose.

(29) In an embodiment, the ethylene/α-olefin multi-block copolymer has hard segments and soft segments, is styrene-free, consists of only (i) ethylene and (ii) a C.sub.4-C.sub.8 α-olefin (and optional additives), and is defined as having a Mw/Mn from 1.7 to 3.5, at least one melting point, Tm, in degrees Celsius, and a density, d, in grams/cubic centimeter, wherein the numerical values of Tm and d correspond to the relationship:
Tm>−2002.9+4538.5(d)−2422.2(d).sup.2,
where the density, d, is from 0.850 g/cc, or 0.860 g/cc, or 0.870 g/cc to 0.875 g/cc, or 0.877 g/cc, or 0.880 g/cc, or 0.890 g/cc; and the melting point, Tm, is from 110° C., or 115° C., or 120° C. to 125° C., or 130° C., or 135° C.

(30) In an embodiment, the ethylene/α-olefin multi-block copolymer is an ethylene/1-octene multi-block copolymer (consisting only of ethylene and octene comonomer) and has one, some, or all of the following properties:

(31) (i) a Mw/Mn from 1.7, or 1.8 to 2.2, or 2.5, or 3.5; and/or

(32) (ii) a density from 0.860 g/cc, or 0.865 g/cc, or 0.870 g/cc, or 0.877 g/cc, or 0.880 g/cc; and/or

(33) (iii) a melting point, Tm, from 115° C., or 118° C., or 119° C., or 120° C. to 120° C., or 123° C., or 125° C.; and/or

(34) (iv) a melt index (MI) from 0.1 g/10 min, or 0.5 g/10 min to 1.0 g/10 min, or 2.0 g/10 min, or 5 g/10 min, or 10 g/10 min; and/or

(35) (v) 50-85 wt % soft segment and 40-15 wt % hard segment; and/or

(36) (vi) from 10 mol %, or 13 mol %, or 14 mol %, or 15 mol % to 16 mol %, or 17 mol %, or 18 mol %, or 19 mol %, or 20 mol % C.sub.4-C.sub.12 α-olefin in the soft segment; and/or

(37) (vii) from 0.5 mol %, or 1.0 mol %, or 2.0 mol %, or 3.0 mol % to 4.0 mol %, or 5 mol %, or 6 mol %, or 7 mol %, or 9 mol % octene in the hard segment; and/or

(38) (viii) an elastic recovery (Re) from 50%, or 60% to 70%, or 80%, or 90%, at 300% 300% min.sup.−1 deformation rate at 21° C. as measured in accordance with ASTM D 1708; and/or

(39) (ix) a polydisperse distribution of blocks and a polydisperse distribution of block sizes.

(40) In an embodiment, the ethylene/α-olefin multi-block copolymer is an ethylene/octene multi-block copolymer. The ethylene/octene multi-block copolymer is sold under the tradename INFUSE™, available from The Dow Chemical Company, Midland, Mich., USA.

(41) In an embodiment, the base polymer for the peroxide-modified ethylene/α-olefin multi-block copolymer is INFUSE™ 9000, available from The Dow Chemical Company.

(42) The ethylene/α-olefin multi-block copolymers can be produced via a chain shuttling process such as described in U.S. Pat. No. 7,858,706, which is herein incorporated by reference. In particular, suitable chain shuttling agents and related information are listed in col. 16 line 39 through col. 19 line 44. Suitable catalysts are described in col. 19 line 45 through col. 46 line 19 and suitable co-catalysts in col. 46 line 20 through col. 51 line 28. The process is described throughout the document, but particularly in col. 51 line 29 through col. 54 line 56. The process is also described, for example, in the following: U.S. Pat. Nos. 7,608,668; 7,893,166; and 7,947,793.

(43) The base ethylene/α-olefin multi-block copolymer may comprise more than one ethylene/α-olefin multi-block copolymer.

(44) In an embodiment, the process includes the step of forming a peroxide-modified ethylene/α-olefin multi-block copolymer. In an embodiment, the peroxide-modified ethylene/α-olefin multi-block copolymer is formed by (i) soaking the base ethylene/α-olefin multi-block copolymer with from 0.05 wt % to 0.10 wt %, or 0.12 wt % peroxide (such as BIBP), based on the combined weight of the base ethylene/α-olefin multi-block copolymer and peroxide; (ii) melt blending the soaked base ethylene/α-olefin multi-block copolymer and peroxide at a temperature from 110° C., or 115° C., or 120° C. to 125° C., or 130° C., or 135° C., or 140° C., or 150° C.; and (iii) compression molding the melt blend to form the peroxide-modified ethylene/α-olefin multi-block copolymer. In an embodiment, the soaking occurs at a temperature of from 23° C., or 30° C., or 40° C., or 50° C., or 55° C., or 60° C. to 65° C., or 70° C., or 75° C., or 80° C.

(45) The peroxide-modified ethylene/α-olefin multi-block copolymer has a gel content of 0%. In other words, the peroxide-modified ethylene/α-olefin multi-block copolymer is crosslink-free, or otherwise void of crosslinking.

(46) The ethylene/α-olefin multi-block copolymer may comprise two or more embodiments disclosed herein.

(47) The peroxide-modified ethylene/α-olefin multi-block copolymer may comprise two or more embodiments disclosed herein.

(48) 2. Peroxide-Modified LDPE

(49) In an embodiment, the composition contains a peroxide-modified LDPE. A “peroxide-modified LDPE” is an LDPE that has been melt blended with a peroxide such that the peroxide acts as a rheology modifying agent in such a way (i) that the degree of LCB in the peroxide-modified LDPE is greater than the degree of LCB in the base LDPE prior to peroxide modification, but (ii) the addition of peroxide does not induce crosslinking, as evidenced by the peroxide-modified LDPE having a gel content of 0%.

(50) The base LDPE is a low density polyethylene. “Low density polyethylene” (or “LDPE”) consists of ethylene homopolymer, or ethylene/α-olefin copolymer comprising at least one C.sub.3-C.sub.10 α-olefin that has a density from 0.915 g/cc to less than 0.940 g/cc and contains long chain branching with broad MWD. LDPE is typically produced by way of high pressure free radical polymerization (tubular reactor or autoclave with free radical initiator). Nonlimiting examples of LDPE include MarFlex™ (Chevron Phillips), LUPOLEN™ (LyondellBasell), as well as LDPE products from Borealis, Ineos, ExxonMobil, and others.

(51) The LDPE has a density from 0.915 g/cc, or 0.916 g/cc, or 0.917 g/cc, or 0.918 g/cc to 0.919 g/cc, or 0.920 g/cc, or 0.925 g/cc, or 0.930 g/cc, or 0.935 g/cc, or 0.940 g/cc.

(52) In an embodiment, the LDPE has a melting point from 90° C., or 95° C., or 100° C., or 105° C., or 108° C. to 109° C., or 110° C., or 115° C., or 120° C., or 125° C.

(53) In an embodiment, the LDPE has a melt index (MI) from 0.1 g/10 min, or 0.5 g/10 min, or 1.0 g/10 min, or 2.0 g/10 min to 2.3 g/10 min, or 2.5 g/10 min, or 3.0 g/10 min, or 4.0 g/10 min, or 5 g/10 min, or 10 g/10 min.

(54) In an embodiment, the LDPE consists of only (i) ethylene and (ii) optionally, a C.sub.4-C.sub.8 α-olefin (and optional additives). In a further embodiment, the LDPE consists of only ethylene. In an embodiment, the LDPE has one, some, or all of the following properties:

(55) (i) a density from 0.915 g/cc, or 0.916 g/cc, or 0.917 g/cc, or 0.918 g/cc to 0.919 g/cc, or 0.920 g/cc; and/or

(56) (ii) a melting point from 100° C., or 105° C., or 108° C. to 109° C., or 110° C., or 115° C.; and/or

(57) (iii) a melt index (MI) from 0.5 g/10 min, or 1.0 g/10 min, or 2.0 g/10 min to 2.3 g/10 min, or 2.5 g/10 min, or 3.0 g/10 min, or 4.0 g/10 min.

(58) The base LDPE may comprise more than one LDPE.

(59) In an embodiment, the process includes the step of forming a peroxide-modified LDPE. The peroxide-modified LDPE is formed by (i) soaking the base LDPE with from 0.01 wt %, or 0.02 wt % to 0.04 wt % peroxide (such as BIBP), based on the combined weight of the base LDPE and peroxide; (ii) melt blending the soaked base LDPE and peroxide at a temperature from 90° C., or 95° C., or 100° C., or 110° C., or 115° C., or 120° C. to 125° C., or 130° C., or 135° C., or 140° C., or 150° C.; and (iii) compression molding the melt blend to form the peroxide-modified LDPE. In an embodiment, the soaking occurs at a temperature of from 23° C., or 30° C., or 40° C., or 50° C., or 55° C., or 60° C. to 65° C., or 70° C., or 75° C., or 80° C.

(60) The peroxide-modified LDPE has a gel content of 0%. In other words, the peroxide-modified LDPE is crosslink-free, or otherwise void of crosslinking

(61) The LDPE may comprise two or more embodiments disclosed herein.

(62) The peroxide-modified LDPE may comprise two or more embodiments disclosed herein.

(63) In an embodiment, the composition includes from 5 wt %, or 10 wt %, or 15 wt %, or 20 wt % to 25 wt %, or 30 wt %, or 35 wt %, or 40 wt %, or 45 wt %, or 50 wt %, or 55 wt %, or 60 wt %, or 70 wt %, or 80 wt %, or 90 wt %, or 95 wt %, or 100 wt % peroxide-modified ethylene-based polymer, based on the total weight of the composition.

(64) In an embodiment, the composition consists essentially of, or consists of, the peroxide-modified ethylene-based polymer.

(65) The peroxide-modified ethylene-based polymer may comprise two or more embodiments disclosed herein.

(66) B. Optional Ethylene/α-Olefin Multi-Block Copolymer

(67) In an embodiment, the composition contains either (i) the peroxide-modified ethylene/α-olefin multi-block copolymer or (ii) the peroxide-modified LDPE, and (iii) an optional ethylene/α-olefin multi-block copolymer. The optional ethylene/α-olefin multi-block copolymer is structurally distinct from the peroxide-modified ethylene/α-olefin multi-block copolymer because the optional ethylene/α-olefin multi-block copolymer has not been rheology modified with peroxide.

(68) The optional ethylene/α-olefin multi-block copolymer may be any base ethylene/α-olefin multi-block copolymer disclosed herein.

(69) The base ethylene/α-olefin multi-block copolymer of the peroxide-modified ethylene/α-olefin multi-block copolymer may be the same or different than the optional ethylene/α-olefin multi-block copolymer. In an embodiment, the base ethylene/α-olefin multi-block copolymer of the peroxide-modified ethylene/α-olefin multi-block copolymer is the same as the optional ethylene/α-olefin multi-block copolymer. In another embodiment, the base ethylene/α-olefin multi-block copolymer of the peroxide-modified ethylene/α-olefin multi-block copolymer is structurally, compositionally, and/or physical different than the optional ethylene/α-olefin multi-block copolymer.

(70) In an embodiment, the optional ethylene/α-olefin multi-block copolymer is an ethylene/1-octene multi-block copolymer.

(71) In an embodiment, the composition contains from 0 wt %, or 5 wt %, or 10 wt %, or 20 wt %, or 30 wt %, or 40 wt %, or 45 wt %, or 50 wt %, or 55 wt %, or 60 wt %, or 65 wt %, or 70 wt %, or 75 wt % to 80 wt %, or 85 wt %, or 90 wt %, or 95 wt % optional ethylene/α-olefin multi-block copolymer, based on the total weight of the composition. In another embodiment, the composition contains from 50 wt %, or 55 wt %, or 60 wt % to 90 wt %, or 95 wt % optional ethylene/α-olefin multi-block copolymer, based on the total weight of the composition.

(72) The optional ethylene/α-olefin multi-block copolymer may comprise two or more embodiments disclosed herein.

(73) C. Optional Additive

(74) In an embodiment, the composition contains one or more additives. Nonlimiting examples of suitable additives include but are not limited to, nucleators (e.g., talc and polytetrafluoroethylene (PTFE)), processing aids, lubricants, stabilizers (antioxidants), foaming aids, surfactants, flow aids, viscosity control agents, coloring agents, copper inhibitors, inorganic fillers (e.g., calcium carbonate (CaCO.sub.3), titanium dioxide (TiO.sub.2)), and combinations thereof. These additives can be added to the peroxide-modified ethylene-based polymer and/or the optional ethylene/α-olefin multi-block copolymer either before or during processing.

(75) In an embodiment, the total amount of additives in the composition is from 0 wt %, or 0.01 to 0.3 wt %, or 0.5 wt %, or 1 wt %, or 2 wt %, or 3 wt %, or 5 wt %, based on the total weight of the composition.

(76) In an embodiment, the composition excludes an additive (e.g., an inorganic filler).

(77) The additive may comprise two or more embodiments discussed herein.

(78) In an embodiment, the composition has a gel content of 0%.

(79) In an embodiment, the composition has a melt strength from 9.0 cN, or 9.5 cN, or 9.7 cN, or 14.0 cN to 21.0 cN, or 29.6 cN, or 30.0 cN, or 35.0 cN, or 40.0 cN, or 50.0 cN. In another embodiment, the composition has a melt strength from 9.0 cN to 10 cN. In another embodiment, the composition has a melt strength from 14.0 cN to 21.0 cN, or 30 cN. Other features being equal, a higher melt strength indicates a composition has improved foaming ability.

(80) In an embodiment, the composition contains from 5 wt %, or 10 wt %, or 15 wt %, or 20 wt % to 25 wt %, or 30 wt %, or 35 wt %, or 40 wt %, or 45 wt %, or 50 wt %, or 55 wt %, or 60 wt %, or 70 wt %, or 80 wt %, or 90 wt %, or 95 wt %, or 100 wt % peroxide-modified ethylene-based polymer and a reciprocal amount of optional ethylene/α-olefin multi-block copolymer, or from 0 wt %, or 5 wt %, or 10 wt %, or 20 wt %, or 30 wt %, or 40 wt %, or 45 wt %, or 50 wt %, or 55 wt %, or 60 wt %, or 65 wt %, or 70 wt %, or 75 wt % to 80 wt %, or 85 wt %, or 90 wt %, or 95 wt % ethylene/α-olefin multi-block copolymer, based on the total weight of the composition.

(81) In an embodiment, the composition contains, consists essentially of, or consists of:

(82) (A) from 10 wt % to 40 wt %, or 50 wt %, or 60 wt %, or 70 wt %, or 80 wt %, or 90 wt %, or 100 wt % of the peroxide-modified ethylene-based polymer selected from a peroxide-modified ethylene/α-olefin multi-block copolymer, a peroxide-modified low density polyethylene, and combinations thereof;

(83) (B) from 0 wt %, or 10 wt %, or 20 wt %, or 30 wt %, or 40 wt %, or 50 wt %, or 60 wt % to 90 wt % of the optional ethylene/α-olefin multi-block copolymer; and

(84) (C) from 0 wt %, or 0.01 to 0.3 wt %, or 0.5 wt %, or 1 wt %, or 2 wt %, or 3 wt %, or 5 wt % additive, based on the total weight of the composition.

(85) It is understood that the sum of the components in each of the compositions disclosed herein, including the foregoing compositions, yields 100 weight percent (wt %).

(86) In an embodiment, the composition contains, consists essentially of, or consists of, the peroxide-modified ethylene/α-olefin multi-block copolymer and the ethylene/α-olefin multi-block copolymer. In a further embodiment, the composition contains, consists essentially of, or consists of, from 10 wt % to 40 wt % of the peroxide-modified ethylene/α-olefin multi-block copolymer and from 60 wt % to 90 wt % of the ethylene/α-olefin multi-block copolymer, based on the total weight of the composition.

(87) In an embodiment, the composition contains, consists essentially of, or consists of, the peroxide-modified LDPE and the ethylene/α-olefin multi-block copolymer. In a further embodiment, the composition contains, consists essentially of, or consists of, from 10 wt % to 20 wt % of the peroxide-modified LDPE and from 80 wt % to 90 wt % of the ethylene/α-olefin multi-block copolymer, based on the total weight of the composition.

(88) In an embodiment, the composition excludes ethylene vinyl acetate (EVA) copolymer.

(89) In an embodiment, the composition excludes ethylene plastomers/elastomers.

(90) The composition may comprise two or more embodiments discussed herein.

(91) In an embodiment, the process includes the step of pelletizing the composition. The pellet may have a diameter from 2.0 mm, or 2.3 mm to 3.0 mm, or 3.5 mm and a length from 2.0 mm, or 2.3 mm to 3.0 mm, or 3.5 mm. In an embodiment, the composition is in the form of a pellet with a diameter from 2.3 mm to 3.0 mm and a length from 2.3 mm to 3.0 mm.

(92) The step of forming a composition may comprise two or more embodiments discussed herein.

(93) ii. Contacting the Composition with a Blowing Agent to Form a Foam Composition; and

(94) iii. Forming Foam Beads Containing the Foam Composition

(95) The process includes the steps of contacting the composition with a blowing agent to form a foam composition; and forming foam beads composed of the foam composition. The composition may be any composition disclosed herein.

(96) A “blowing agent” is a substance that is capable of producing a cellular structure in the composition via a foaming process. A nonlimiting example of a suitable blowing agent is a physical blowing agent. Nonlimiting examples of suitable physical blowing agents include an inert gas such as nitrogen (N.sub.2), a carbon gas (e.g., CO, CO.sub.2, etc.), helium, and argon; hydrocarbon such as methane, propane, and butane (e.g., isobutane), pentane; and halogenated hydrocarbons such as dichlorodifluoromethane, dichloromonofluoromethane, monochlorodifluoromethane, trichloromonofluoromethane, monochloropentafluoroethane, and trichlorotrifluoroethane.

(97) In an embodiment, the physical blowing agent is carbon dioxide (CO.sub.2). A nonlimiting example of a suitable carbon dioxide is supercritical carbon dioxide. Supercritical carbon dioxide is a fluid state of carbon dioxide that is held at or above its critical temperature (31.10° C.) and critical pressure (7.39 MPa).

(98) In an embodiment, the blowing agent is a physical blowing agent to the exclusion of chemical blowing agents.

(99) Nonlimiting examples of methods of contacting the composition with a blowing agent to form a foam composition, and forming foam beads including the foam composition include (a) contacting the composition with a blowing agent, and undergoing a sudden pressure drop (depressurization) or a temperature increase of the contacted composition in an autoclave to form the foam beads, and (b) via foam extrusion with under-water pelletizing.

(100) A “foam composition” is the present composition with a cellular structure. In other words, the present composition in its native state and prior to contact with the blowing agent is void of a cellular structure, and after contact with the blowing agent and depressurization, the present composition is a foam composition with a cellular structure. The cells may be open cells, closed cells, or combinations thereof. In an embodiment, the cells have a uniform, or substantially uniform, cell size.

(101) A “foam bead” is a foamed structure containing the foam composition, the structure having a diameter from 4 mm, or 5 mm to 6 mm, or 7 mm; and/or a length from 4 mm, or 5 mm to 6 mm, or 7 mm.

(102) In an embodiment, the blowing agent is present in an amount of from 0.001 parts by weight, or 0.005 parts by weight, to 0.05 parts by weight, or 0.10 parts by weight of the composition to be foamed. In another embodiment, the blowing agent is present in an amount of from 0.1 wt %, or 0.5 wt %, or 1.0 wt % to 2.0 wt %, or 5.0 wt %, or 8.0 wt %, or 10.0 wt %, based on the combined weight of the composition and blowing agent.

(103) In an embodiment, the process includes contacting the composition with the physical blowing agent at a temperature of from 100° C., or 110° C., or 115° C., or 120° C. to 125° C., or 130° C., or 135° C.

(104) In an embodiment, the composition is contacted with the physical blowing agent (e.g., supercritical carbon dioxide) by soaking the composition in the physical blowing agent.

(105) In an embodiment, the composition is contacted with the physical blowing agent (e.g., supercritical carbon dioxide) via impregnation of composition pellets with the blowing agent in an autoclave. The impregnating occurs at a temperature within ±0° C. to ±10° C. of the melting point of the peroxide-modified ethylene-based polymer and/or the optional ethylene/α-olefin multi-block copolymer. In a further embodiment, the impregnating occurs at a temperature from 110° C., or 115° C., or 120° C. to 125° C., or 130° C., or 135° C. In an embodiment, the impregnating occurs with a physical blowing agent pressure of from 5 MPa, or 8 MPa, or 10 MPa, or 11 MPa to 12 MPa, or 13 MPa, or 15 MPa, or 20 MPa, or 25 MPa, or 30 MPa and a saturation time of from 0.5 hours, or 1.0 hour to 1.5 hours, or 2.0 hours, or 3.0 hours. Following the saturation time, the autoclave is depressed to 25° C. and 0.1 MPa. During depression, the impregnated composition pellets expand to form foam beads containing the foam composition.

(106) In another embodiment, the composition is contacted with the physical blowing agent (e.g., supercritical carbon dioxide) via foam extrusion with under-water pelletizing. The physical blowing agent may be mixed with an organic polymer to be foamed in advance or may be supplied into an extruder from a blowing agent supply opening formed on the barrel of the extruder. In an embodiment, the contacting occurs in a foaming extruder. In a further embodiment, the process includes feeding the composition (such as the composition pellets) into a foaming extruder and supplying the physical blowing agent into the extruder from a blowing agent supply opening formed on the barrel of the extruder at a pressure of from 5 MPa, or 8 MPa, or 10 MPa, or 11 MPa to 12 MPa, or 13 MPa, or 15 MPa, or 20 MPa, or 25 MPa, or 30 MPa, the extrusion occurring at a temperature from 110° C., or 115° C. to 130° C., or 135° C. The composition is foamed as it exits the extruder, for the pressure drop results in foaming by the dissolved gas. The foam composition is then pelletized under water to form foam beads.

(107) The foam bead is not crosslinked. In other words, the foam bead has a gel content of 0%. A foam bead that is not crosslinked is advantageous because it provides a thermoplastic foam bead. In other words, the foam bead may be melt processed further to form a foamed article. Foam beads that are crosslinked (i.e., have a gel content of greater than 0%, typically from 60% to 80%) cannot be melt processed to form an article because the crosslinked foam beads cannot melt together and fuse to form a single article. Furthermore, foam beads that are crosslinked (i.e., have a gel content of greater than 0%, typically from 60% to 80%) cannot be sintered because the foam beads cannot fuse to form a uniform article.

(108) In an embodiment, the foam bead has a foam density of less than 0.300 g/cc. In another embodiment, the foam bead has a foam density from 0.150 g/cc, or 0.190 g/cc, or 0.195 g/cc to 0.210 g/cc, or 0.223 g/cc, or 0.230 g/cc, or 0.236 g/cc, or 0.240 g/cc, or 0.286 g/cc, or 0.290 g/cc, or 0.295 g/cc, or 0.299 g/cc. Other features being equal, a lower foam density indicates a composition has improved foaming ability.

(109) In an embodiment, the foam bead is formed from a composition having a gel content of 0%.

(110) In an embodiment, the foam bead is formed from a composition having a melt index from greater than 0 g/10 min, or 0.001 g/10 min, or 0.01 g/10 min, or 0.30 g/10 min to 0.44 g/10 min, or 0.45 g/10 min, or 0.50 g/10 min.

(111) In an embodiment, the foam bead is formed from a composition having a low shear viscosity (at 1 rad/sec) from 30,000 Pa.Math.s, or 31,000 Pa.Math.s, or 31,500 Pa.Math.s, or 31,900 Pa.Math.s, or 38,000 Pa.Math.s to 47,500 Pa.Math.s, or 48,000 Pa.Math.s, or 50,000 Pa.Math.s.

(112) In an embodiment, the foam bead is formed from a composition having a high shear viscosity (at 100 rad/sec) from 2,000 Pa.Math.s, or 2,500 Pa.Math.s, or 2,600 Pa.Math.s, or 2,900 Pa.Math.s, or 3,000 Pa.Math.s to 3,500 Pa.Math.s, or 4,000 Pa.Math.s.

(113) In an embodiment, the foam bead has at least one melting point from 110° C., or 115° C., or 120° C. to 125° C., or 130° C., or 135° C.

(114) In an embodiment, the composition contains, consists essentially of, or consists solely of, the peroxide-modified ethylene/α-olefin multi-block copolymer, and, optionally, an additive, and the composition has one, some, or all of the following properties:

(115) (a) a gel content of 0%; and/or

(116) (b) a melt strength from 14.0 cN, or 15.0 cN, or 20.0 cN, or 25.0 cN, or 28.0 cN to 29.6 cN, or 30.0 cN; and/or

(117) (c) a melt index from greater than 0 g/10 min to 0.01 g/10 min; and the foam bead containing the foam composition has one or both of the following properties:

(118) (i) a gel content of 0%; and/or

(119) (ii) a foam density from 0.190 g/cc, or 0.195 g/cc to 0.210 g/cc, or 0.215 g/cc, or 0.220 g/cc.

(120) In an embodiment, the composition contains, consists essentially of, or consists of, from 5 wt %, or 10 wt % to 40 wt %, or 50 wt % of the peroxide-modified ethylene/α-olefin multi-block copolymer and from 50 wt %, or 60 wt % to 90 wt %, or 95 wt % of the ethylene/α-olefin multi-block copolymer, and optionally, an additive, based on the total weight of the composition, and the composition has one, some, or all of the following properties:

(121) (a) a gel content of 0%; and/or

(122) (b) a melt strength from 9.0 cN to 9.7 cN, or 10 cN; and/or

(123) (c) a melt index from 0.01 g/10 min, or 0.30 g/10 min to 0.35 g/10 min, or 0.40 g/10 min, or 0.45 g/10 min, or 0.50 g/10 min; and/or

(124) (d) a low shear viscosity (at 1 rad/sec) from 36,000 Pa.Math.s, or 37,000 Pa.Math.s, or 38,000 Pa.Math.s to 47,500 Pa.Math.s, or 48,000 Pa.Math.s, or 50,000 Pa.Math.s; and/or

(125) (e) a high shear viscosity (at 100 rad/sec) from 3,000 Pa.Math.s, or 3,100 Pa.Math.s, or 3,200 Pa.Math.s to 3,400 Pa.Math.s, or 3,500 Pa.Math.s, or 4,000 Pa.Math.s; and

(126) the foam bead containing the foam composition has one or both of the following properties:

(127) (i) a gel content of 0%; and/or

(128) (ii) a foam density from 0.200 g/cc, or 0.210 g/cc, or 0.220 g/cc, or 0.230 g/cc, or 0.235 g/cc to 0.290 g/cc, or 0.295 g/cc, or 0.299 g/cc.

(129) In an embodiment, the composition contains, consists essentially of, or consists of, from 5 wt %, or 10 wt % to 20 wt %, or 30 wt %, or 40 wt % of the peroxide-modified LDPE and from 60 wt %, or 70 wt %, or 80 wt % to 90 wt %, or 95 wt % of the ethylene/α-olefin multi-block copolymer, and optionally, an additive, based on the total weight of the composition, and the composition has one, some, or all of the following properties:

(130) (a) a gel content of 0%; and/or

(131) (b) a melt strength from 14.0 cN to 21.0 cN, or 25.0 cN; and/or

(132) (c) a melt index from 0.30 g/10 min, or 0.35 g/10 min, or 0.40 g/10 min to 0.44 g/10 min, or 0.45 g/10 min, or 0.50 g/10 min; and/or

(133) (d) a low shear viscosity (at 1 rad/sec) from 30,000 Pa.Math.s, or 31,000 Pa.Math.s, or 31,500 Pa.Math.s to 36,500 Pa.Math.s, or 37,000 Pa.Math.s, or 39,000 Pa.Math.s; and/or

(134) (e) a high shear viscosity (at 100 rad/sec) from 2,000 Pa.Math.s, or 2,500 Pa.Math.s, or 2,600 Pa.Math.s to 3,000 Pa.Math.s, or 3,200 Pa.Math.s, or 3,500 Pa.Math.s; and

(135) the foam bead containing the foam composition has one or both of the following properties:

(136) (i) a gel content of 0%; and/or

(137) (ii) a foam density from 0.180 g/cc, or 0.185 g/cc, or 0.190 g/cc, or 0.195 g/cc to 0.225 g/cc, or 0.230 g/cc, or 0.235 g/cc.

(138) The present disclosure also provides a foam bead formed from the present process. The foam bead may be any foam bead disclosed herein. In an embodiment, the composition has a melt strength from 9 cN to 30 cN and a gel content of 0%; and the foam bead has a foam density of less than 0.300 g/cc.

(139) The step of contacting the composition with a blowing agent to form a foam composition may comprise two or more embodiments discussed herein.

(140) The step of forming foam beads containing the foam composition may comprise two or more embodiments discussed herein.

(141) iv. Forming an Article from the Foam Beads

(142) In an embodiment, the process includes the step of forming an article from the foam beads.

(143) The article is formed via sintering of the foam beads. A nonlimiting method of sintering includes steam-chest molding. Steam-chest molding occurs at a temperature from 80° C., or 90° C. to 100° C., or 110° C. and/or a pressure from 0.1 MPa, or 0.2 MPa to 1.0 MPa, or 1.2 MPa. Bounded by no particular theory, it is believed that the high melting temperature (110° C. to 135° C.) of the peroxide-modified ethylene/α-olefin multi-block copolymer and/or the high melting temperature (110° C. to 135° C.) of the ethylene/α-olefin multi-block copolymer enables the foam beads to withstand the high temperature of steam-chest molding without shrinkage (i.e., without an increase in foam density). In contrast, foam beads formed from polymers with lower melting points, such as ethylene vinyl acetate copolymer (e.g., TAISOX™ 7360M with a melting point of 80° C., available from Formosa Plastics Corporation) and polyolefin elastomers (e.g., ENGAGE™ 8003 with a melting point of 77° C., available from The Dow Chemical Company), are known to exhibit shrinkage (i.e., an increase in foam density) due to steam-chest molding.

(144) In an embodiment, after exposure to 100° C. for 5 minutes, the foam bead exhibits a change in density of from ±2%, or ±1%, or ±0.5% to 0%. The change in density is calculated in accordance with the following Equation 1:

(145) $\begin{array}{cc}\mathrm{Change}\mathrm{in}\mathrm{Foam}\mathrm{Density}=\frac{\begin{array}{c}\mathrm{initial}\mathrm{foam}\mathrm{density}-\\ \mathrm{foam}\mathrm{density}\mathrm{after}\\ \mathrm{exposure}\mathrm{to}100°C.\\ \mathrm{for}5\min \end{array}}{\mathrm{initial}\mathrm{foam}\mathrm{density}}\times 100& \mathrm{Equation}1\end{array}$
wherein “initial foam density” is the density of the foam prior to exposure to 100° C. for 5 minutes.

(146) Nonlimiting examples of suitable articles made from the present foam composition, and further the present foam beads, include footwear (e.g., midsoles of footwear), packaging, sporting goods, construction materials, and insulation.

(147) The step of forming an article from the foam beads may comprise two or more embodiments discussed herein.

(148) The present process may comprise two or more embodiments discussed herein.

(149) Foam Bead

(150) The present disclosure also provides a foam bead. The foam bead contains the composition including a peroxide-modified ethylene-based polymer selected from a peroxide-modified ethylene/α-olefin multi-block copolymer, a peroxide-modified low density polyethylene, and combinations thereof. The composition has (a) a melt strength from 9 cN to 30 cN and (b) a gel content of 0%. The foam bead has a foam density of less than 0.300 g/cc.

(151) The foam bead may be any foam bead disclosed herein. The foam bead may be formed from any foam composition disclosed herein.

(152) In an embodiment, the foam bead contains, consists essentially of, or consists solely of, the composition containing, consisting essentially of, or consisting solely of, peroxide-modified ethylene/α-olefin multi-block copolymer, and, optionally, an additive; and the composition has

(153) (a) a melt strength from 14.0 cN, or 15.0 cN, or 20.0 cN, or 25.0 cN, or 28.0 cN to 29.6 cN, or 30.0 cN; and

(154) (b) a gel content of 0%; and

(155) (c) optionally, a melt index from greater than 0 g/10 min to 0.01 g/10 min; and

(156) the foam bead has (i) a foam density from 0.190 g/cc, or 0.195 g/cc to 0.210 g/cc, or 0.215 g/cc, or 0.220 g/cc; and (ii) optionally, a gel content of 0%.

(157) In an embodiment, the foam bead contains, consists essentially of, or consists solely of, the composition containing, consisting essentially of, or consisting solely of, from 5 wt %, or 10 wt % to 40 wt %, or 50 wt % of the peroxide-modified ethylene/α-olefin multi-block copolymer and from 50 wt %, or 60 wt % to 90 wt %, or 95 wt % of the ethylene/α-olefin multi-block copolymer, and optionally, an additive, based on the total weight of the composition, and the composition has

(158) (a) a melt strength from 9.0 cN to 9.7 cN, or 10 cN;

(159) (b) a gel content of 0%;

(160) (c) optionally, a melt index from 0.01 g/10 min, or 0.30 g/10 min to 0.35 g/10 min, or 0.40 g/10 min, or 0.45 g/10 min, or 0.50 g/10 min;

(161) (d) optionally, a low shear viscosity (at 1 rad/sec) from 36,000 Pa.Math.s, or 37,000 Pa.Math.s, or 38,000 Pa.Math.s to 47,500 Pa.Math.s, or 48,000 Pa.Math.s, or 50,000 Pa.Math.s; and

(162) (e) optionally, a high shear viscosity (at 100 rad/sec) from 3,000 Pa.Math.s, or 3,100 Pa.Math.s, or 3,200 Pa.Math.s to 3,400 Pa.Math.s, or 3,500 Pa.Math.s, or 4,000 Pa.Math.s; and

(163) the foam bead has (i) a foam density from 0.200 g/cc, or 0.210 g/cc, or 0.220 g/cc, or 0.230 g/cc, or 0.235 g/cc to 0.290 g/cc, or 0.295 g/cc, or 0.299 g/cc; and (ii) optionally, a gel content of 0%.

(164) In an embodiment, the foam bead contains, consists essentially of, or consists solely of, the composition containing, consisting essentially of, or consisting solely of, from 5 wt %, or 10 wt % to 20 wt %, or 30 wt %, or 40 wt % of the peroxide-modified LDPE and from 60 wt %, or 70 wt %, or 80 wt % to 90 wt %, or 95 wt % of the ethylene/α-olefin multi-block copolymer, and optionally, an additive, based on the total weight of the composition, and the composition has

(165) (a) a melt strength from 14.0 cN to 21.0 cN, or 25.0 cN;

(166) (b) a gel content of 0%;

(167) (c) optionally, a melt index from 0.30 g/10 min, or 0.35 g/10 min, or 0.40 g/10 min to 0.44 g/10 min, or 0.45 g/10 min, or 0.50 g/10 min;

(168) (d) optionally, a low shear viscosity (at 1 rad/sec) from 30,000 Pa.Math.s, or 31,000 Pa.Math.s, or 31,500 Pa.Math.s to 36,500 Pa.Math.s, or 37,000 Pa.Math.s, or 39,000 Pa.Math.s;

(169) (e) optionally, a high shear viscosity (at 100 rad/sec) from 2,000 Pa.Math.s, or 2,500 Pa.Math.s, or 2,600 Pa.Math.s to 3,000 Pa.Math.s, or 3,200 Pa.Math.s, or 3,500 Pa.Math.s; and

(170) the foam bead has (i) a foam density from 0.180 g/cc, or 0.185 g/cc, or 0.190 g/cc, or 0.195 g/cc to 0.225 g/cc, or 0.230 g/cc, or 0.235 g/cc; and (ii) optionally, a gel content of 0%.

(171) In an embodiment, the foam bead has at least one melting point from 110° C., or 115° C., or 120° C. to 125° C., or 130° C., or 135° C.

(172) In an embodiment, the foam bead excludes ethylene vinyl acetate (EVA) copolymer.

(173) In an embodiment, the foam bead excludes ethylene plastomers/elastomers.

(174) The foam bead may comprise two or more embodiments discussed herein.

(175) By way of example, and not limitation, some embodiments of the present disclosure will now be described in detail in the following Examples.

EXAMPLES

(176) Materials used in the examples are provided in Table 1 below.

(177) TABLE-US-00001 TABLE 1 Material/ Description Properties Source INFUSE ™ 9530 ethylene/1-octene multi-block copolymer The Dow density = 0.887 g/cc; melting point = 119° C.; Chemical melt index (190° C./2.16 kg) = 5.0 Company g/10 min; pellets INFUSE ™ 9000 ethylene/1-octene multi-block copolymer The Dow density = 0.877 g/cc; melting point = 120° C.; Chemical melt index (190° C./2.16 kg) = 0.5 g/10 min Company TAISOX ™ ethylene vinyl acetate (EVA) copolymer Formosa 7360M vinyl acetate content = 21.0 wt %; density = Plastics 0.941 g/cc; melting point = 80° C.; melt index Corporation (190° C./2.16 kg) = 2.0 g/10 min; pellets ENGAGE ™ ethylene/1-butene copolymer; polyolefin The Dow HM 7487 elastomer density = 0.860 g/cc; melting Chemical point = 37° C.; melt index (190° C./2.16 Company kg) = < 0.50 g/10 min; pellets DOW ™ LDPE ethylene homopolymer (LDPE) The Dow 621I density = 0.918 g/cc; melting point = 108° C.; Chemical melt index (190° C./2.16 kg) = 2.3 Company g/10 min; pellets bis(t-butylperoxy) melting point = 41° C.; flakes AkzoNobel diisopropylbenzene Polymer (BIBP) Chemistry
Preparation of Peroxide-Modified Ethylene-Based Polymer

(178) Peroxide-modified ethylene/α-olefin multi-block copolymer (peroxide-modified INFUSE™ 9000) and peroxide-modified LDPE (peroxide-modified LDPE 621I) are prepared by soaking the base ethylene/α-olefin multi-block copolymer and the base LDPE, respectively, in 1 wt % BIBP at 65° C., adding base component to the desired concentration, and then melt blending the soaked base component and peroxide with a Haake mixer at 120° C. The melt blend is then compression molded at 185° C. to form a peroxide-modified ethylene-based polymer. The concentration of each component is provided in Table 2.

(179) The gel content of the peroxide-modified ethylene-based polymers is measured. The results are provided in Table 2.

(180) TABLE-US-00002 TABLE 2 Peroxide-Modified Peroxide-Modified INFUSE ™ 9000 LDPE 621I INFUSE ™ 9000 99.90 wt % — DOW ™ LDPE 621I — 99.96 wt % bis(t-butylperoxy)  0.10 wt %  0.04 wt % diisopropylbenzene (BIBP) Gel Content 0% 0%
Preparation of Foam Beads

(181) Compositions are formed from the materials of Table 1 and Table 2. The contents of each composition is provided below in Table 3. Compositions are measured for gel content, melt strength, melt index, low shear viscosity (1 rad/s), and high shear viscosity (100 rad/s). The results are provided in Table 3.

(182) The compositions are then impregnated with 11 MPa supercritical carbon dioxide (CO.sub.2) at 120° C. in a closed stainless steel autoclave. The saturation time is 1.5 hours. Then, foam beads are obtained via quick depressing (to 0.1 MPa, 25° C., within 1 second) using a pressure relief valve. Foam beads are measured for foam density. The results are provided in Table 3. In Table 3, “CS” refers to Comparative Sample.

(183) TABLE-US-00003 TABLE 3* Ex. 1 Ex. 2 Ex. 3 Ex. 4 Ex. 5 Peroxide-Modified 100 10 40 — — INFUSE ™ 9000 Peroxide-Modified — — — 10 20 LDPE 621I INFUSE ™ 9000 — 90 60 90 80 INFUSE ™ 9530 — — — — — DOW ™ LDPE 621I — — — — — TAISOX ™ 7360M — — — — — ENGAGE ™ HM 7487 — — — — — Total (wt %) 100 100 100 100 100 Composition Properties Gel Content (%) 0 0 0 0 0 Melt Strength 29.6 9.0 9.7 14.1 21.0 (cN) Melt Index <0.01 0.35 0.32 0.44 0.40 (g/10 min) Low Shear 45,552 38,436 47,193 36,054 31,964 Viscosity (Pa .Math. s, 1 rad/s) High Shear 2,503 3,240 3,322 2,964 2,693 Viscosity (Pa .Math. s, 100 rad/s) Foam Bead Properties Foam Density 0.210 0.286 0.236 0.223 0.195 (g/cc) CS 1 CS 2 CS 3 CS 4 CS 5 Peroxide-Modified — — — — — INFUSE ™ 9000 Peroxide-Modified — — — — — LDPE 621I INFUSE ™ 9000 100 90 70 80 — INFUSE ™ 9530 — — — — 100 DOW ™ LDPE 621I — — — 20 — TAISOX ™ 7360M — 10 — — — ENGAGE ™ HM 7487 — — 30 — — Total (wt %) 100 100 100 100 100 Composition Properties Gel Content (%) 0 0 0 0 0 Melt Strength 5.5 5.3 7.5 13.3 <1.0 (cN) Melt Index 0.49 0.68 0.42 0.52 5 (g/10 min) Low Shear 35,387 30,044 38,917 33,353 6341 Viscosity (Pa .Math. s, 1 rad/s) High Shear 3,173 2,824 3,533 2,657 1592 Viscosity (Pa .Math. s, 100 rad/s) Foam Bead Properties Foam Density 0.314 0.381 0.454 0.305 0.430 (g/cc) *wt %, based on the weight of the total composition

(184) As shown in Table 3, foam beads formed from a composition containing (i) a peroxide-modified ethylene/α-olefin multi-block copolymer (peroxide-modified INFUSE™ 9000) or (ii) a peroxide-modified LDPE (Peroxide-Modified LDPE 621I) (Ex. 1-Ex. 5) advantageously exhibit (a) a gel content of 0%, as measured on the composition, and (b) a foam density of less than 0.300 g/cc. Consequently, Ex. 1-Ex. 5 advantageously exhibit a low foam density (less than 0.300 g/cc), while also maintaining a thermoplastic nature (gel content of 0%). Furthermore, the composition advantageously exhibits a melt strength from 9 cN to 30 cN.

(185) In contrast, comparative foam beads formed from a composition that lacks a peroxide-modified ethylene-based polymer (CS 1-CS 5) exhibit a foam density greater than 0.300 g/cc and/or the composition has a melt strength of less than 9 cN and/or.

(186) Foam beads formed from a composition containing 100 wt % peroxide-modified INFUSE™ 9000 (Ex. 1) advantageously exhibit a low foam density (0.210 g/cc) and the composition advantageously exhibits a high melt strength (29.6 cN), each indicating that the foam beads are formed from a composition with improved foamability. In contrast, foam beads formed from a composition containing 100 wt % INFUSE™ 9000 that has not been peroxide-modified (CS 1) exhibits a higher density (0.314 g/cc) and the composition exhibits a lower melt strength (5.5 cN). Without being bound by any particular theory, it is believed that the improvement in melt strength between CS 1 and Ex. 1 is due to the increased long chain branching in the peroxide-modified INFUSE™ 9000 (Ex. 1).

(187) While the gel content of the foam bead Ex. 1-5 is not measured, Applicant expects that the foam bead of Ex. 1-5 each has a gel content of 0% because there is no further crosslinking reaction during the depressurization of the composition that forms the cellular structure of the foam beads.

(188) It is specifically intended that the present disclosure not be limited to the embodiments and illustrations contained herein, but include modified forms of those embodiments including portions of the embodiments and combinations of elements of different embodiments as come within the scope of the following claims.