Process aid for melt processable polymers
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 non-fluorinated melt processable polymer 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 non-fluorinated melt processable polymer, and wherein said interfacial agent is molten at said extrusion temperature, with the proviso that an ionomer is not present in said process aid composition.
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 said non-fluorinated melt processable polymer is a polyolefin.
13 . The process aid composition of claim 1 wherein the fluoroelastomer is selected from the group consisting of copolymers of i) vinylidene fluoride and hexafluoropropylene; ii) vinylidene fluoride and chlorotrifluoroethylene; iii) vinylidene fluoride and 1-hydropentafluoropropylene; iv) vinylidene fluoride and 2-hydropentafluoropropylene; v) vinylidene fluoride, hexafluoropropylene and tetrafluoroethylene; vi) vinylidene fluoride, 1-hydropentafluoropropylene and tetrafluoroethylene; vii) vinylidene fluoride, 2-hydropentafluoropropylene and tetrafluoroethylene; viii) tetrafluoroethylene and propylene; and ix) tetrafluoroethylene, propylene and vinylidene fluoride.
14 . The process aid composition of claim 13 wherein the fluoroelastomer is a copolymer of vinylidene fluoride and hexafluoropropylene.
15 . The process aid composition of claim 1 wherein said fluoroelastomer is a copolymer of vinylidene fluoride and hexafluoropropylene, said interfacial agent is selected from the group consisting of i) a poly(oxyalkylene) polymer and ii) a polycaprolactone, and wherein said non-fluorinated melt processable polymer is polyethylene.
16 . The process aid composition of claim 15 wherein said interfacial agent is a poly(oxyalkylene) polymer comprising polyethylene glycol.
17 . A process aid composition for use in an extrudable non-fluorinated melt processable polymer 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 non-fluorinated melt processable polymer, and wherein said interfacial agent is molten at said extrusion temperature, with the proviso that a polar side-group-containing adjuvant is not present in said process aid composition.
18 . The process aid composition of claim 17 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.
19 . The process aid composition of claim 18 wherein said interfacial agent is an aliphatic polyester.
20 . The process aid composition of claim 19 wherein said aliphatic polyester is a polycaprolactone having a number average molecular weight between 1000 and 32000.
21 . The process aid composition of claim 20 wherein said polycaprolactone has a number average molecular weight between 2000 and 10000.
22 . The process aid composition of claim 21 wherein said polycaprolactone has a number average molecular weight between 2000 and 4000.
23 . The process aid composition of claim 18 wherein said interfacial agent is a poly(oxyalkylene) polymer.
24 . The process aid composition of claim 23 wherein said poly(oxyalkylene) polymer is a polyethylene glycol.
25 . The process aid composition of claim 18 wherein said interfacial agent is a silicone-polyether copolymer.
26 . The process aid composition of claim 17 wherein said interfacial agent at the extrusion temperature wets a surface of said fluoroelastomer.
27 . The process aid composition of claim 17 wherein said interfacial agent has a melt viscosity lower than that of said fluoroelastomer.
28 . The process aid composition of claim 17 wherein said non-fluorinated melt processable polymer is a polyolefin.
29 . The process aid composition of claim 17 wherein the fluoroelastomer is selected from the group consisting of copolymers of i) vinylidene fluoride and hexafluoropropylene; ii) vinylidene fluoride and chlorotrifluoroethylene; iii) vinylidene fluoride and 1-hydropentafluoropropylene; iv) vinylidene fluoride and 2-hydropentafluoropropylene; v) vinylidene fluoride, hexafluoropropylene and tetrafluoroethylene; vi) vinylidene fluoride, 1-hydropentafluoropropylene and tetrafluoroethylene; vii) vinylidene fluoride, 2-hydropentafluoropropylene and tetrafluoroethylene; viii) tetrafluoroethylene and propylene; and ix) tetrafluoroethylene, propylene and vinylidene fluoride.
30 . The process aid composition of claim 29 wherein the fluoroelastomer is a copolymer of vinylidene fluoride and hexafluoropropylene.
31 . The process aid composition of claim 17 wherein said fluoroelastomer is a copolymer of vinylidene fluoride and hexafluoropropylene, said interfacial agent is selected from the group consisting of i) a poly(oxyalkylene) polymer and ii) a polycaprolactone, and wherein said non-fluorinated melt processable polymer is polyethylene.
32 . The process aid composition of claim 31 wherein said interfacial agent is a poly(oxyalkylene) polymer comprising polyethylene glycol.