Process aid for melt processable polymers
View Patent ↗Extrusion processability of non-fluorinated melt-processable polymers is improved by introducing a fluoropolymer process aid by means whereby the weight average particle size of the fluoropolymer is greater than 2 microns as it reaches the extruder die entrance.
1. A process aid composition for use in an extrudable linear low density polyethylene at an extrusion temperature, said process aid composition comprising:
A) at least 1 weight percent, based on total weight of said process aid composition, of a fluoroelastomer having a Mooney viscosity, measured per ASTM D1646 at 121° C., large rotor, condition ML 1+10 minutes, of 60 to 80; and
B) at least 1 weight percent, based on total weight of said process aid composition, of an interfacial agent, said interfacial agent being a thermoplastic polymer different from both said fluoroelastomer and said linear low density polyethylene, and wherein said interfacial agent is in the liquid state at said extrusion temperature.
2. The process aid composition of claim 1 wherein said interfacial agent is selected from the group consisting of i) silicone-polyether copolymers; ii) aliphatic polyesters; iii) aromatic polyesters; iv) polyether polyols; and v) poly(oxyalkylene) polymers.
3. The process aid composition of claim 2 wherein said interfacial agent is an aliphatic polyester.
4. The process aid composition of claim 3 wherein said aliphatic polyester is a polycaprolactone having a number average molecular weight between 1000 and 32000.
5. The process aid composition of claim 4 wherein said polycaprolactone has a number average molecular weight between 2000 and 10000.
6. The process aid composition of claim 5 wherein said polycaprolactone has a number average molecular weight between 2000 and 4000.
7. The process aid composition of claim 2 wherein said interfacial agent is a poly(oxyalkylene) polymer.
8. The process aid composition of claim 7 wherein said poly(oxyalkylene) polymer is a polyethylene glycol.
9. The process aid composition of claim 2 wherein said interfacial agent is a silicone-polyether copolymer.
10. The process aid composition of claim 1 wherein said interfacial agent at the extrusion temperature wets a surface of said fluoroelastomer.
11. The process aid composition of claim 1 wherein said interfacial agent has a melt viscosity lower than that of said fluoroelastomer.
12. The process aid composition of claim 1 wherein the fluoroelastomer consists essentially of a copolymer of vinylidene fluoride and hexafluoropropylene.
13. The process aid composition of claim 1 wherein said fluoroelastomer consists of a copolymer of vinylidene fluoride and hexafluoropropylene and wherein said interfacial agent is selected from the group consisting of i) a poly(oxyalkylene) polymer and ii) a polycaprolactone.
14. The process aid composition of claim 13 wherein said interfacial agent is a poly(oxyalkylene) polymer comprising polyethylene glycol.
15. A process aid composition for reducing conditioning time in an extrudable linear low density polyethylene passing through a die at an extrusion temperature, said process aid composition comprising:
A) at least 1 weight percent, based on total weight of said process aid composition, of a fluoroelastomer having a Mooney viscosity, measured per ASTM D1646 at 121° C., large rotor, condition ML 1+10 minutes, of 60 to 80; and
B) at least 1 weight percent based on total weight of said process aid composition, of an interfacial agent, said interfacial agent being a thermoplastic polymer different from both said fluoroelastomer and said linear low density polyethylene, and wherein said interfacial agent is in the liquid state at said extrusion temperature.
16. The process aid composition of claim 15 wherein said interfacial agent is selected from the group consisting of i) silicone-polyether copolymers; ii) aliphatic polyesters; iii) aromatic polyesters; iv) polyether polyols; and v) poly(oxyalkylene) polymers.
17. The process aid composition of claim 16 wherein said interfacial agent is an aliphatic polyester.
18. The process aid composition of claim 17 wherein said aliphatic polyester is a polycaprolactone having a number average molecular weight between 2000 and 10000.
19. The process aid composition of claim 16 wherein said interfacial agent is a poly(oxyalkylene) polymer.
20. The process aid composition of claim 19 wherein said poly(oxyalkylene) polymer is a polyethylene glycol.
21. The process aid composition of claim 15 wherein said fluoroelastomer is a copolymer consisting essentially of vinylidene fluoride and hexafluoropropylene.
22. The process aid composition of claim 15 wherein said fluoroelastomer is a copolymer consisting of vinylidene fluoride and hexafluoropropylene, and said interfacial agent is selected from the group consisting of i) a poly(oxyalkylene) polymer and ii) a polycaprolactone.
23. A process aid composition for reducing die pressure in an extrudable linear low density polyethylene passing through a die at an extrusion temperature, said process aid composition comprising:
A) at least 1 weight percent, based on total weight of said process aid composition, of a fluoroelastomer having a Mooney viscosity, measured per ASTM D1646 at 121° C., large rotor, condition ML 1+10 minutes, of 60 to 80; and
B) at least 1 weight percent, based on total weight of said process aid composition, of an interfacial agent, said interfacial agent being a thermoplastic polymer different from both said fluoroelastomer and said linear low density polyethylene, and wherein said interfacial agent is in the liquid state at said extrusion temperature.
24. The process aid composition of claim 23 wherein said interfacial agent is selected from the group consisting of i) silicone-polyether copolymers; ii) aliphatic polyesters; iii) aromatic polyesters; iv) polyether polyols; and v) poly(oxyalkylene) polymers.
25. The process aid composition of claim 24 wherein said interfacial agent is an aliphatic polyester.
26. The process aid composition of claim 25 wherein said aliphatic polyester is a polycaprolactone having a number average molecular weight between 2000 and 10000.
27. The process aid composition of claim 24 wherein said interfacial agent is a poly(oxyalkylene) polymer.
28. The process aid composition of claim 27 wherein said poly(oxyalkylene) polymer is a polyethylene glycol.
29. The process aid composition of claim 23 wherein said fluoroelastomer is a copolymer consisting essentially of vinylidene fluoride and hexafluoropropylene.
30. The process aid composition of claim 23 wherein said fluoroelastomer is a copolymer consisting of vinylidene fluoride and hexafluoropropylene, and said interfacial agent is selected from the group consisting of i) a poly(oxyalkylene) polymer and ii) a polycaprolactone.
31. A process aid composition for reducing melt fracture in an extrudable linear low density polyethylene passing through a die at an extrusion temperature, said process aid composition comprising:
A) at least 1 weight percent, based on total weight of said process aid composition, of a fluoroelastomer having a Mooney viscosity, measured per ASTM D1646 at 121° C., large rotor, condition ML 1+10 minutes, of 60 to 80; and
B) at least 1 weight percent, based on total weight of said process aid composition, of an interfacial agent, said interfacial agent being a thermoplastic polymer different from both said fluoroelastomer and said linear low density polyethylene, and wherein said interfacial agent is in the liquid state at said extrusion temperature.
32. The process aid composition of claim 31 wherein said interfacial agent is selected from the group consisting of i) silicone-polyether copolymers; ii) aliphatic polyesters; iii) aromatic polyesters; iv) polyether polyols; and v) poly(oxyalkylene) polymers.
33. The process aid composition of claim 32 wherein said interfacial agent is an aliphatic polyester.
34. The process aid composition of claim 33 wherein said aliphatic polyester is a polycaprolactone having a number average molecular weight between 2000 and 10000.
35. The process aid composition of claim 32 wherein said interfacial agent is a poly(oxyalkylene) polymer.
36. The process aid composition of claim 35 wherein said poly(oxyalkylene) polymer is a polyethylene glycol.
37. The process aid composition of claim 31 wherein said fluoroelastomer is a copolymer consisting essentially of vinylidene fluoride and hexafluoropropylene.
38. The process aid composition of claim 31 wherein said fluoroelastomer is a copolymer consisting of vinylidene fluoride and hexafluoropropylene, and said interfacial agent is selected from the group consisting of i) a poly(oxyalkylene) polymer and ii) a polycaprolactone.