A POLYMER ADDITIVE POWDER COMPOSITION

Abstract

A polymer additive powder composition comprising (a) slip agent(s); (b) antiblock agent(s); and (c) optionally one or more components; wherein the slip to antiblock agent(s) is in the range of 80:20 to 95:5 parts by weight and wherein the slip agent encapsulates the antiblock agent(s).

Claims

1. A polymer additive powder composition comprising (a) slip agent(s); (b) antiblock agent(s); and (c) optionally one or more components; wherein the slip to antiblock agent(s) is in the range of 80:20 to 95:5 parts by weight and wherein the slip agent encapsulates the antiblock agent(s).

2. A polymer additive powder composition as claimed in claim 1 is a free flowing powder composition.

3. A polymer additive composition as claimed in claim 1 with d50 particle size of 300 to 500 microns as measured by Malvern particle size analyzer.

4. A polymer additive composition as claimed in claim 1 wherein the slip agent(s) is selected from primary and secondary fatty amides and mixtures thereof.

5. A polymer additive composition as claimed in claim 1 wherein the antiblock agent(s) is selected from inorganic compounds.

6. A polymer additive composition as claimed in claim 1 wherein the components are selected from antioxidants, antistatic agents, stabilizers, flame retardants, metal soaps and nucleating agents.

7. A polymer additive composition as claimed in claim 1 wherein the additive is used at 0.05 to 0.5% by weight of the polymer for manufacturing into polymer films.

8. A polymer additive composition as claimed in claim 1 wherein the polymer is selected from LDPE, LLDPE, PP and EVA.

9. A polymer additive composition as claimed in claim 1 when added to polymer resin is processed into an uniform, transparent film with improved film quality such as optical properties and deposition on equipments when measured by ASTM D-7310 and 1003 as compared to treated or untreated silica or other antiblocks.

10. A polymer additive composition as claimed in claim 1 when added to polymer resin is processed into an uniform, transparent film with dynamic and static coefficient of friction less than 0.3 when measured by ASTM D 1894.

11. A polymer additive composition as claimed in claim 1 when added to polymer resin is processed into an uniform, transparent film with dynamic and static coefficient of friction less than 0.3 and coefficient of friction is 3 to 5 times lower than treated or untreated silica or other antiblocks when measured by ASTM D 1894.

12. A polymer additive composition as claimed in claim 1 when added to polymer resin is processed into an uniform, transparent film with blocking force of less than 5 gm when measured with 5 kg load @50° C. by ASTM D-3354.

13. A polymer additive composition as claimed in claim 1 when added to polymer resin is processed into an uniform, transparent film with blocking force of less than 5 gm and the blocking force is 4 to 5 times lower than treated or untreated silica or other antiblocks when measured with 5 kg load @50° C. by ASTM D-3354.

14. A process for the preparation of polymer additive composition as claimed in claim 1 comprising melting slip agent(s), adding antiblock agent, encapsulating and powdering to obtain a free flowing powder using a spray tower.

Description

DESCRIPTION OF THE INVENTION

[0018] The polymer film manufacturing process essentially requires two additives a) anti-blocking agents and b) slip agents among other components. These two additives are typically used in concentrations of 1000 to 3000 ppm in polymer films. The two additives may be used as separate powders or pre-mixed compositions. Conventional integrated blends have significantly high % of silica as antiblock agent for e.g Sylobloc 243H has 43% silica and 57% erucamide, Sylobloc 250/250H 50% silica and 50% erucamide.

[0019] According to the first embodiment of the present invention is a polymer additive powdercomposition comprising [0020] (a) slip agent(s); [0021] (b) antiblock agent(s); and [0022] (c) optionally one or more components; wherein the slip to antiblock agent(s) is in the range of 80:20 to 95:5 parts by weight and wherein the slip agent encapsulates the antiblock agent(s).

[0023] Preferably, the polymer additive powder composition of the present invention is a free flowing powder.

[0024] The polymer additive powdercomposition of the present invention has d50 particle size of 300 to 500 microns as measured by Laser diffraction analyzer such as Malvern Particle size analyzer.

[0025] The slip agent(s) may be selected from primary and secondary fatty amides such as oleamide, erucamide, gadoleamide,isostearamide, bisoleamide,biserucamide, stearylerucamide, oleylpalmitamide, oleyloleamide and the like.

[0026] The antiblock agent may be selected form inorganic compounds selected from silica, alumina, talc, limestone, clay, celite, titanium dioxide, calcium hydrogen phosphate, calcium carbonate, synthetic zeolites and the like.

[0027] The components may be selected form antioxidants, antistatic agents, stabilizers, flame retardants, metal soaps, nucleating agents and the like.

[0028] The antioxidants may be selected from sterically hindered phenols, secondary aryl amines, phosphorous compositions, thioesters, hydroxylamines and the like.

[0029] The antistatic agents may be selected from ammonium salts, glycerin esters, anionic compounds and the like.

[0030] The flame retardants may be selected from halogenated organic compounds, metal hydrates and mixtures thereof.

[0031] The polymer additive powder composition of the present invention is stable, free flowing and displays no sign of separation of the components even after prolonged pneumatic conveyance and different modes of transportation.

[0032] The polymer additive powder composition of the present invention is used at 0.05 to 0.5% by weight of the polymer for manufacturing polymeric films.

[0033] The polymer may be selected from LDPE, LLDPE, PP and EVA.

[0034] The polymer additive powder composition of the present invention when added to polymer resin is processed into an uniform, transparent film with improved film quality such as optical properties and deposition on equipments when measured by ASTM D-7310 and 1003 as compared to treated or untreated silica or other antiblocks.

[0035] The polymer additive powder composition of the present invention when added to polymer resin is processed into an uniform, transparent film with dynamic and static coefficient of frictionless than 0.3 when measured by ASTM D 1894.

[0036] Particularly, the polymer additive powder composition of the present invention when added to polymer resin is processed into an uniform, transparent film with dynamic and static coefficient of frictionless than 0.3 and coefficient of friction is 3 to 5 times lower than treated or untreated silica or other antiblocks when measured by ASTM D 1894.

[0037] The polymer additive powder composition of the present invention when added to polymer resin is processed into an uniform, transparent film with blocking force of less than 5 gm when measured with 5 kg load @50° C. by ASTM D-3354.

[0038] Particularly, the polymer additive powder composition of the present invention when added to polymer resin is processed into an uniform, transparent film with blocking force of less than 5 gm and the blocking force is 4 to 5 times lower than treated or untreated silica or other antiblocks when measured with 5 kg load @50° C. by ASTM D-3354.

[0039] According to the second embodiment of the present invention is a process for the preparation of polymer additive powder composition comprising melting the slip agent(s), adding antiblock agent, encapsulating and powdering to obtain a free flowing powder using a spray tower. Preferably, a process for the preparation of polymer additive powder composition comprising melting the slip agent(s) at 10 to 20° C. above the melting point of the slip agent(s), adding antiblock agent, encapsulating and powdering to obtain a free flowing powder using a spray tower.

[0040] Encapsulation facilitates use of minimum amount of inorganic antiblock agents together with slip agents and provides desired antiblock and slip properties with elimination or reduction of the disadvantages arising out of higher amounts of inorganic antiblock agents such as surface roughness of the film.

[0041] The free flowing powder with d50 particle size of300 to 500 microns as measured by Laser diffraction analyzer such as Malvern Particle size analyzer.

[0042] The polymer additive powder composition of the present invention may be added to polymer resin prior to processing into polymer films such as LDPE, LLDPE, PP and EVA films. The polymer additive disperses uniformly in the polymer mixture enabling uniform, transparent polymer films.

[0043] The polymer films may be manufactured by blown, cast and BOPP process for polyolefinic materials such as PP, LDPE, LLDPE and EVA.

[0044] The polymer additive of the present invention provides several advantages in processing of the polymeric film, end use of the film during packaging and physical appearance of the polymeric film in view of improved properties like lower coefficient of friction, lower blocking force and less number of fisheyes and gels.

[0045] The polymeradditive of the present invention provides increased process efficiency as the additive comprises both slip agent and antiblock agent so no separate addition required, increased output as faster line speed, no die lip buildup as the coefficient of friction between film and collapsing board is lower. Additionally, supports smoother processing without defects rendering films totally free of hard particles, fisheyes, gels and lower pinholes arising from the hard particles.

[0046] At the processing end the polymer additive of the present invention provides smoother film winding as the blocking between two film surfaces is reduced.

[0047] At the film user end film rolls can be easily unwound post long term storage due to lower blocking, enabling higher efficiency of packaging.

[0048] The film has better aesthetic look in view of lower haze values leading to improved transparency and gloss.

EXAMPLES

Example 1: Preparation of the Polymer Additive Composition

[0049] Melt 80-95 gm erucamide at 100deg C and 20-5 gm of silica is added. The mixture is encapsulated and powdered using spray tower.

Example 2: Comparison of a Slip/Antiblock Study in LDPE Films

[0050] TABLE-US-00001 Test Parameters Control Polymer additive powder composition of the invention Silica treated (Sylobloc 45H) Silica LDPE (3MFI) 1000 ppm 2500 ppm 1000 ppm 2500 ppm 1000 ppm 2500 ppm COF-Ref-ASTM D-1894 Average Dynamic COF 0.85 0.11 0.10 0.49 0.43 0.52 0.46 Average Static COF 0.87 0.13 0.12 0.49 0.47 0.56 0.49 Blocking force (gms)-Ref-ASTM D-3354 Blocking Force (gms) *with 5 kg load @50 deg C 48 2 Nil 25 16 22 12 Fish eyes and Gels Ref-ASTM-D-7310 Size of fisheyes and Gels <0.4 mm-3-6 <0.4 mm-4-6 <0.4 mm-5-7 <0.4 mm -5-8 <0.4 mm-6-8 <0.4 mm -5-9 <0.4 m m-6-10 Haze Values Test Method ASTM D 1003 Haze Values% 13 13.5 - 15.5 - 15 -

Example 3: Comparison of a Slip/Antiblock Study in LLDPE (octene Grade) Films

[0051] TABLE-US-00002 Control Polymer additive powder composition of the invention Silica treated (Sylobloc 45H) Silica LLDPE (2MFI) 1000 ppm 2500 ppm 1000 ppm 2500 ppm 1000 ppm 2500 ppm COF-Ref-ASTM D-1894 Average Dynamic COF 0.72 0.11 0.10 0.50 0.47 0.46 0.41 Average Static COF 0.73 0.14 0.11 0.55 0.49 0.5 0.48 Blocking force (gms)-Ref-ASTM D-3354 Blocking Force (gms) *with 5 kg load @50 deg C 68 5 Nil 35 19 28 17 Fish eyes and Gels Ref-ASTM-D-7310 Size of fisheyes and Gels <0.4 mm-2-4 <0.4 mm-2-5 <0.4 mm-2-5 <0.4mm -2-4 <0.4 mm-3-5 <0.4mm -3-4 <0.4 m m-3-6 Haze Values Test Method ASTM D 1003 Haze Values% 20 30 - 30 - 34 -

Example 4 :Comparison of a Slip/Antiblock Study in PP Films

[0052] TABLE-US-00003 Control Polymer additive powder composition of the invention Silica treated (Sylobloc 45H) Silica PP(3MFI) Homopolymer 1000 ppm 2500 ppm 1000 ppm 2500 ppm 1000 ppm 2500 ppm COF-Ref-ASTM D-1894 Average Dynamic COF 0.57 0.27 0.17 0.42 0.34 0.45 0.43 Average Static COF 0.59 0.27 0.19 0.45 0.38 0.49 0.46 Blocking force (gms)-Ref-ASTM D-3354 Blocking Force (gms) *with 5 kg load @50 deg C 4 Nil Nil Nil Nil Nil Nil Fish eyes and Gels Ref-ASTM-D-7310 Size of fisheyes and Gels <0.4 mm-3-5 <0.4 mm -4-6 <0.4 mm-5-7 <0.4 mm -4-6 <0.4 mm-6-8 <0.4 mm -5-7 <0.4 mm -6-9

Example 5: FinaSlip EAB

Set I) Findings from Additional Studies

[0053] Our additional studies have been carried out with the base polymer of LLDPE (butene copolymer grade) and a typical formulation with silica and erucamide has been included in the evaluation for comparison purpose.

TABLE-US-00004 LLDPE (butene grade MFI: 0.9) Silica + Erucamide (Recipe for comparison) FinaSlip EAB (ppm) Sample description Control (2000+1000) ppm 2000 3000 Blocking Force Induced, gms 132.5 16 41.7 18.3 Kinetic CoF 1.03 0.141 0.128 0.113

Observations

[0054] FinaSlip EAB can offer effective antiblocking and better slip performance at 2000 ppm compared to the typical recipe.FinaSlip EAB can offer comparable antiblocking and superior slip performance at 3000 ppm compared to the typical recipe.

Set II) Additional Data of FinaSlip EAB - Superior Film Quality/Visual Appearance Haze Values Determination)

[0055] TABLE-US-00005 Control Silica + Erucamide (Recipe for comparison) (2500+1000) ppm FinaSlip EAB (ppm) 900 1500 2000 CoF 0.877 0.114 0.286 0.152 0.119 Blocking force (gm) [Induced] 141 26 77 57 58 Transmittance (%) 85.5 82.2 85.4 85 86.1 Gloss at 60° 90 70 97 96 98 Haze (%) 18.3 22 15.5 14.8 15.1

Observations

[0056] FinaSlip EAB can offer effective antiblocking and better slip performance at 2000 ppm compared to the typical recipe. FinaSlip EAB can offer significantly superior film quality, which is reflected in the lower haze values noted in the specimens with FinaSlip EAB compared to the specimens prepared with typical recipe.