Application of organosilane coatings for improved anti-adhesive properties enabling facilitated demolding in polymer processing

Abstract

Easy and residue-free demolding is an everlasting topic in the plastics processing industry. Typically, facile ejection of the produced parts from the mold is provided by separation agents (silicon sprays, surface coatings). In this work, a perfluoroalkyl-based organosilane coating is applied to exchangeable substrates of an injection mold. Besides the simple application, the coating can also be restored easily in a procedure based on flame treatment. Coating and recoating are proven by contact angle measurements with water, while the anti-adhesive effect and the related relief during demolding are evaluated using a special measuring device in an instrumented two-plate injection mold. The results reveal that the organosilane layer reduces the demolding forces and the resulting static friction coefficient by 50%. Furthermore, multiple recoating significantly improves the durability of the anti-adhesive coating. Based on these findings, the easily applicable and renewable organosilane coating represents a suitable alternative to conventional release coatings.