Patent ID: 8574478

Claim:
A method of using a fatty acid ester as a slip additive in a thermoplastic moulding composition in the production of colourless moulded polyethylene terephthalate articles in the form of bottle preforms, the method comprising incorporating said fatty acid ester into a bottle preform moulded from polyethylene terephthalate, said slip additive reducing the coefficient of friction of the preform, wherein the fatty acid ester is selected from the group consisting of: (a) acetylated glycerol fatty acid esters; (b) sorbitan fatty acid esters; and (c) refined rapeseed oil, montanic acid triglyceride, PEG-400 dilaurate, PEG-200 dioleate, acetylated triglyceride, and mixtures of two or more thereof; wherein the moulded polyethylene terephthalate articles in the form of bottle preforms are colourless; and wherein the thermoplastic moulding composition does not comprise a fatty amide.