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EP-4536463-B1 - PROCESS TO PREPARE THERMOPLASTIC COMPOSITIONS COMPRISING FLUORINE FREE POLYMER PROCESSING AIDS

EP4536463B1EP 4536463 B1EP4536463 B1EP 4536463B1EP-4536463-B1

Inventors

  • TAYLOR, JARED
  • WANG, JUN
  • TIKUISIS, TONY

Dates

Publication Date
20260513
Application Date
20230606

Claims (17)

  1. A process for preparing a thermoplastic composition extrudate, the process comprising extruding a thermoplastic composition in a melt extrusion process; the thermoplastic composition comprising: i) a linear polyethylene; ii) from 200 to 4000 parts per million (based on the weight the linear polyethylene) of a poly(ether-block-amide) copolymer; and iii) from 200 to 4000 parts per million (based on the weight of the linear polyethylene) of a polycaprolactone polymer; wherein the linear polyethylene is selected from the group consisting of LLDPE, MDPE, VLDPE, HDPE, and mixtures thereof; wherein the poly(ether-block-amide) copolymer comprises polyamide blocks and polyether blocks; wherein the thermoplastic composition is substantially free of fluoropolymers; and wherein the melt extrusion process is carried out in the absence of fluoropolymers.
  2. The process of claim 1, wherein the thermoplastic composition further comprises: iv) 200 to 4000 parts per million (based on the weight of the linear polyethylene) of a polyethylene glycol.
  3. The process of claim 1 or 2, wherein the linear polyethylene comprises zinc oxide; or wherein the linear polyethylene comprises hydrotalcite.
  4. The process of any one of claims 1 to 3, wherein the linear polyethylene is a LLDPE.
  5. The process of claim 4, wherein the LLDPE has a melt index, I 2 of from 0.1 to 5.0 grams per 10 minutes; or wherein the LLDPE has a density of from 0.910 to 0.936 g/cm 3 ; or wherein the LLDPE is an ethylene copolymer comprising polymerized ethylene and one or more alpha olefin selected from the group consisting of 1-butene, 1-hexene, and 1-octene.
  6. The process of any one of claims 1 to 5, wherein the poly(ether-block-amide) copolymer comprises polyamide blocks which are polyamide-12 (PA-12) blocks and polyether blocks which are polyethylene glycol (PEG) blocks.
  7. The process of claim 6, wherein the polyamide-12 (PA-12) blocks represent about 40 to 50 weight percent of the poly(ether-block-amide) copolymer, and the polyethylene glycol (PEG) blocks represent about 60 to 50 weight percent of the poly(ether-block-amide) copolymer.
  8. The process of any one of claims 1 to 5, wherein the poly(ether-block-amide) copolymer comprises from 10 to 20 polyamide blocks and from 10 to 20 polyether blocks.
  9. The process of any one of claims 1 to 5, wherein the poly(ether-block-amide) copolymer comprises from 10 to 20 polyamide blocks which are polyamide-12 (PA-12) blocks and from 10 to 20 polyether blocks which are polyethylene glycol (PEG) blocks.
  10. The process of any one of claims 1 to 6, wherein the poly(ether-block-amide) copolymer has a number average molecular weight, Mn of from about 50,000 to about 75,000 g/mol.
  11. The process of any one of claims 1 to 10, wherein the polycaprolactone polymer is a polycaprolactone diol polymer, with a number average molecular Mn, of from about 500 g/mol to about 6,000 g/mol and which is derived from epsilon-caprolactone using a 1,4-butanediol as an initiator.
  12. The process of any one of claims 1 to 11, wherein the thermoplastic composition comprises from 200 to 2,000 parts per million (based on the weight the linear polyethylene) of the poly(ether-block-amide) copolymer.
  13. The process of any one of claims 1 to 12, wherein the thermoplastic composition comprises from 200 to 2,000 parts per million (based on the weight of the linear polyethylene) of the polycaprolactone polymer.
  14. The process of any one of claims 1 to 13, wherein the melt extrusion process is conducted at a shear rate which would produce a thermoplastic composition extrudate having melt fracture defects if carried out using a thermoplastic composition consisting essentially of the linear polyethylene.
  15. A process for preparing a thermoplastic composition extrudate, the process comprising: a) preparing a thermoplastic composition by combining a linear polyethylene with 200 to 4,000 parts per million of at least one poly(ether-block-amide) copolymer (based on the weight of the linear polyethylene) and from 200 to 4,000 parts per million (based on the weight of the linear polyethylene) of at least one polycaprolactone polymer; and b) extruding the thermoplastic composition in a melt extrusion process; wherein the linear polyethylene is selected from the group consisting of LLDPE, MDPE, VLDPE, HDPE, and mixtures thereof; wherein the at least one poly(ether-block-amide) copolymer comprises polyamide blocks and polyether blocks; wherein the thermoplastic composition is substantially free of fluoropolymers; and wherein the melt extrusion process is carried out in the absence of fluoropolymers.
  16. A process for preparing a thermoplastic composition extrudate, the process comprising: a) preparing a thermoplastic composition by combining a linear polyethylene with 200 to 4,000 parts per million of at least one poly(ether-block-amide) copolymer (based on the weight of the linear polyethylene), from 200 to 4000 parts per million (based on the weight of the linear polyethylene) of at least one polycaprolactone polymer, and 200 to 4,000 parts per million (based on the weight of the linear polyethylene) of at least one polyethylene glycol; and b) extruding the thermoplastic composition in a melt extrusion process; wherein the linear polyethylene is selected from the group consisting of LLDPE, MDPE, VLDPE, HDPE, and mixtures thereof; wherein the at least one poly(ether-block-amide) copolymer comprises polyamide blocks and polyether blocks; wherein the thermoplastic composition is substantially free of fluoropolymers; and wherein the melt extrusion process is carried out in the absence of fluoropolymers.
  17. The process of claim 15 or claim 16, wherein the linear polyethylene comprises zinc oxide; or wherein the linear polyethylene comprises hydrotalcite.

Description

TECHNICAL FIELD The present disclosure relates to processing aids for the extrusion of thermoplastic polyolefins and works well in the absence of fluorinated alkene based fluoropolymers. BACKGROUND ART During the extrusion of polyolefin polymers surface defects may occur including those referred to as sharkskin, snakeskin and orange peel, and each type of surface defect is generally related to the rheology of the polymer melt. A particularly severe form of surface defect which may occur is "melt fracture" which is believed to result when the shear rate at the surface of the polyolefin polymer is sufficiently high that the surface of the polymer begins to fracture. That is, there is a slippage of the surface of the extruded polymer relative to the body of the polymer melt. The surface generally cannot flow fast enough to keep up with the body of the extrudate and a fracture in the melt occurs resulting in a severe loss of surface properties for the extrudate polymer. U.S. Pat. No. 3,125,547 discloses blends of polyethylene and small amounts of fluoropolymers to provide a smooth surface on a polyethylene extrudate at high extrusion speeds. U.S. Pat. No. 3,222,314 discloses blends of polyethylene and low molecular weight polyethylene glycol to provide heat sealable film which is suitable for printing. U.S. Pat. No. 4,013,622 teaches the use of low molecular weight polyethylene glycol to reduce the incidence of "breakdowns" during the manufacture of polyethylene film. Similarly, U.S. Pat. No. 4,540,538 teaches that pinstriping may be reduced during the extrusion of a polyolefin into film by the use of a combination of (i) a polyethylene glycol; (ii) a hindered phenolic antioxidant; and (iii) a selected inorganic antiblock material. Further patents relate to the use of a combination of polyalkylene oxides and fluorocarbon polymers as a processing aid in extrusion of polyolefins. These patents include U.S. Pat. No. 4,855,360 which discloses and claims a composition of matter comprising the polyolefin and the processing aid and U.S. Pat. No. 5,015,693 which claims the processing aid per se. These patents demonstrate the use of relatively low molecular weight polyethylene glycols (e.g. having molecular weights of from about 400 Da to about 20,000 Da) in combination with fluorocarbon polymers as polymer processing aids and further, that in the absence of the fluoropolymer these polyethylene glycols were not very effective at reducing melt defects. U.S. Pat. No. 6,294,604 describes the use of a combination of a fluoropolymer, a polyethylene glycol, and magnesium oxide as a polymer processing additive package. U.S. Pat. No. 5,986,005 describes the use of a combination of an elastomeric fluoropolymer and a polyamide/polyether block copolymer for use as a polymer processing aid. U.S. Pat. No. 6,894,118 discloses a polymer processing aid which is a combination of a fluoropolymer and a polycaprolactone having a number average molecular weight, Mn of from 2,000 to 10,000. U.S. Pat. No. 7,449,520 discloses the use of polycaprolactone, which is a polyester polymer, as an interfacial agent, in combination with a fluoropolymer processing aid. The extrusion of melt processable polymers comprising a fluoropolymer processing aid having a weight average particle size of greater than 2 microns is disclosed. Fluoroelastomers and fluoropolymers are expensive materials so there is an economic incentive to avoid their use. Further, perfluorinated alkanes and perfluorinated surfactant compounds, such as for example, perfluoroctane sulfonate and perfluorooctanoic acid, which are used during the production of fluoropolymers, are increasingly being recognized for possible negative environmental impacts. In U.S. Pat. Appl. No. 2005/0070644, we disclosed that high molecular weight polyethylene glycol, in particular PEG having a molecular weight of greater than 20,000 g/mol, reduces melt fracture during polyolefin extrusions in the absence of fluoropolymers. U.S. Pat. No. 10,982,079 also details the performance of polymer processing aids in the absence of added fluoropolymers. The polymer processing aid comprises a high molecular weight polyethylene glycol which has improved thermal stability by virtue of the inclusion of a metal salt of a carboxylic acid, a sulfonic acid, or an alkyl sulfate. European patent application EP 1600475 A1 discloses the use of a thermoplastic composition, preferably comprising linear low density polyethylene, and comprising a polyether-block copolyimide as an additive for densification and sintering respectively in rotomolding processes. SUMMARY OF INVENTION We now report that, the use of a block copolymer having polyamide blocks and polyether blocks, together with a polycaprolactone works well as a polymer processing aid during the extrusion of thermoplastic polyolefins in the absence of fluoropolymer processing aids. The present disclosure provides a useful alternative to fluorinated alkene based polymer process