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 composition for extrusion through a die, said composition comprising:
A) a linear low density polyethylene;
B) 25 to 2000 ppm 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
C) an interfacial agent in an amount no more than a 5:1 weight ratio of interfacial agent to fluoroelastomer, said interfacial agent being different from both said non-fluorinated melt processable polymer and said fluoroelastomer.
2 . The 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 composition of claim 2 wherein said interfacial agent is an aliphatic polyester.
4 . The composition of claim 3 wherein said interfacial agent is a polycaprolactone having a number average molecular weight between 1000 and 32000.
5 . The composition of claim 4 wherein said interfacial agent is a polycaprolactone having a number average molecular weight between 2000 and 10000.
6 . The composition of claim 5 wherein said interfacial agent is a polycaprolactone having a number average molecular weight between 2000 and 4000.
7 . The composition of claim 2 wherein said interfacial agent is a poly(oxyalkylene) polymer.
8 . The composition of claim 7 wherein said poly(oxyalkylene) polymer is a polyethylene glycol.
9 . The composition of claim 1 wherein said linear low density polyethylene is a copolymer of ethylene and an alpha-olefin copolymer wherein the alpha-olefin is selected from the group consisting of propylene, butene-1, hexene-1, octene-1, decene-1 and octadecene.
10 . The 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.
11 . The composition of claim 10 wherein the fluoroelastomer is a copolymer of vinylidene fluoride and hexafluoropropylene.
12 . The composition of claim 1 wherein said fluoroelastomer is a copolymer of vinylidene fluoride and hexafluoropropylene and said interfacial agent is a polyethylene glycol.
13 . A composition for extrusion through a die, said composition comprising:
A) a linear low density polyethylene;
B) 25 to 2000 ppm 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
C) an interfacial agent in an amount no more than a 5:1 weight ratio of interfacial agent to fluoroelastomer, said interfacial agent being different from both said non-fluorinated melt processable polymer and said fluoroelastomer
with the proviso that an ionomer is not present in said composition.
14 . The composition of claim 13 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.
15 . The composition of claim 14 wherein said interfacial agent is an aliphatic polyester.
16 . The composition of claim 15 wherein said interfacial agent is a polycaprolactone having a number average molecular weight between 1000 and 32000.
17 . The composition of claim 15 wherein said interfacial agent is a poly(oxyalkylene) polymer.
18 . The composition of claim 17 wherein said poly(oxyalkylene) polymer is polyethylene glycol.
19 . The composition of claim 13 wherein said linear low density polyethylene is a copolymer of ethylene and an alpha-olefin copolymer wherein the alpha-olefin is selected from the group consisting of propylene, butene-1, hexene-1, octene-1, decene-1 and octadecene.
20 . The composition of claim 13 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.
21 . The composition of claim 20 wherein the fluoroelastomer is a copolymer of vinylidene fluoride and hexafluoropropylene.
22 . The composition of claim 13 wherein said fluoroelastomer is a copolymer of vinylidene fluoride and hexafluoropropylene and said interfacial agent is a polyethylene glycol.
23 . The composition of claim 22 wherein said copolymer of vinylidene fluoride and hexafluoropropylene is a dipolymer.