| abstract |
The invention relates to a process for producing an (ultra) high molecular weight polyethylene (HMWPE) article comprising:n incorporating into the HMWPE resin a Hindered Amine Light Stabilizer (HALS) and cross-link the (U)HMWPE during or after molding the (U)HMWPE resin. nn In particular the invention relates to a process comprising the following steps:n a) incorporating into (U)HMWPE resin a Hindered Amine Light Stabilizer (HALS) according to one of the following general formulas or combinations hereof: nn n n n n n n n n n n n  wherein R 1 up to and including R 5 are herein independent substituents; for example containing hydrogen, ether, ester, amine, amide, alkyl, alkenyl, alkynyl, aralkyl, cycloalkyl and/or aryl groups, which substituents may in turn contain functional groups, for example alcohols, ketones, anhydrides, imines, siloxanes, ethers, carboxyl groups, aldehydes, esters, amides, imides, amines, nitriles, ethers, urethanes and any combination thereof; n b) molding the (U)HMWPE resin comprising the HALS, resulting in an article; n c) cross-linking and sterilizing the article via gamma radiation or electron beam radiation; n d) optionally, if step b results in a stock shape, machining the stock shape into an article; n wherein step c and step d can be performed in either order. |