ADDITIVE
This invention describes a polymer composition having reduced torque during processing comprising poly(ethylene terephthalate) (PET) and an internal additive, where the internal additive is a polyglycerol fatty acid ester having a degree of esterification of at least 70% and where the concentration of the internal additive is below 5 wt %. This invention further describes a use of said composition for packaging materials and a use of an internal additive in the processing of the polymer composition as a lubricant and/or an anti-blocker during processing of the polymer, where said internal additive is a polyglycerol fatty acid ester having a degree of esterification of at least 70% and 2-10 glycerol repeating units.
1 - 6 . (canceled)
7 . A method for making a polymer composition, wherein:
the method comprises mixing a polymer and an internal additive;
the polymer composition exhibits reduced torque during processing and reduced surface friction relative to an identical composition without the internal additive;
the internal additive is a polyglycerol fatty acid ester in a concentration of 0.1-5 wt %, having a degree of esterification of at least 70%, 2-5 glycerol repeating units and a fatty acid chain length of C2-C24; and
the internal additive acts as a lubricant and/or an anti-blocker during processing of the polymer.
8 . The method according to claim 7 , characterized in that, said fatty acid chain length is C12-C18.
9 . The method according to claim 7 , characterized in that, said internal additive is a triglycerol ester.
10 . The method according to claim 7 , characterized in that, said polymer is a polyester.
11 . The method according to claim 10 , characterized in that, said polymer is poly(ethylene terephthalate) (PET).
12 . The method according to claim 10 , characterized in that, said polymer is poly(trimethylene terephthalate).
13 . The method according to claim 7 , characterized in that, the degree of esterification is at least 80%.
14 . The method according to claim 7 , characterized in that, said internal additive has high thermal stability with a thermogravimetric analysis (TGA) of less than 25% weight loss at 300° C.
15 - 16 . (canceled)
17 . The method according to claim 7 , characterized in that, the concentration of said internal additive is 0.3-3 wt %.
18 . The method according to claim 19 , characterized in that, the degree of esterification is at least 80%.
19 . The method according to claim 7 , characterized in that, the concentration of said internal additive is 0.5-3 wt %.
20 . The method according to claim 21 , characterized in that, the degree of esterification is at least 80%.