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 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 2000 and 4000
5. The composition of claim 2 wherein said interfacial agent is a poly(oxyalkylene) polymer.
6. The composition of claim 5 wherein said poly(oxyalkylene) polymer is a polyethylene glycol.
7. 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-l, octene-1, decene-1 and octadecene.
8. The composition of claim 1 wherein said fluoroelastomer is a copolymer consisting of vinylidene fluoride and hexafluoropropylene, and said interfacial agent is a polyethylene glycol.