Siloxane Masterbatch  MB50-320 - Multibase, A Dow Corning Company - 

Ultra-high molecular weight functionalised siloxane polymer dispersed in ethylene vinyl acetate.

DOW CORNING MB50-320 Masterbatch is a pelletised formulation containing 50% of an ultra-high molecular weight siloxane polymer dispersed in EVA carrier. It is designed to be used as an additive in most EVA compatible systems to impart benefits such as processing improvements and modification of surface characteristics.

Liquid siloxane plastic additives have been used for several years to improve the lubricity and flow of thermoplastics. They are effective in this role although some difficulties have been experienced in the corporation of liquids into thermoplastic melts without the use of specialised equipment. It has also been difficult to produce masterbatches greater than 20% liquid siloxane because of processing difficulty and bleed problems.

The DOW CORNING® MB Series Masterbatches address these problems by supplying a high concentration of an ultra high molecular weight siloxane as a dispersion in a dry pellet form in a variety of thermoplastics.

BENEFITS
When added to EVA or similar at 0.1% to 1.0%, improved processing and flow of the resin is expected, including better mould filling, less extruder torque, internal lubrication, mould release and faster throughput. At higher addition levels, 1% to 5% siloxane, improved surface properties are expected, including lubricity, slip, lower coefficient of friction, and greater mar and abrasion resistance.

The DOW CORNING MB Series Masterbatches are expected to give improved benefits compared to conventional lower molecular weight siloxane additives, e.g. less screw slippage, a lower and more consistent dynamic coefficient of friction, and fewer printing problems.

HOW TO USE
DOW CORNING MB Series Masterbatches may be processed in the same way as the thermoplastics on which they are based. Sufficient DOW CORNING MB50-320 Masterbatch should be blended with virgin polymer pellets to give the desired siloxane level in the final product. DOW CORNING MB50-320 Masterbatch pellets can be added at the feed hopper during extrusion.