Silicone -masterbatches, oils, gums and powders- as additives for thermoplastics, elastomers and TPE

Masterbatches properties The level of the silicone, fluid or gum, varies from 10 % to 50 %. The silicone form can be oil from more or less high viscosity, or UHMW gum from more or less high molecular weight (Mn up to 300,000 with viscosity above 15 million cst). The most current thermoplastic matrices are polyethylene (HDPE, LDPE, LLDPE), polypropylene, high impact polystyrene, polyacetal, nylon 6, EVA, Hytrel. The particle sizes of the silicone in the masterbatch are less than 10 microns with an average value in the order of 2 microns. The silicone masterbatches are often approved for food contact. In USA, some specific grades are agreed FDA (regulation 121-2514) for polymeric coatings used as a food contact surface. General guidelines for the use of silicone masterbatches The masterbatches in solid form, pellet- shaped, free flowing, are easy to use as the other types of additives. They have to be efficiently mixed with the raw material, for example by tumbling. The levels of silicone depend on the desired effect: less than 1 % for mould release to few per cent to enhance the scratch resistance of TPOs.