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Dow Corning siloxane powders (also known as resin modifiers) are 100% active,
free-flowing powders available in both non-reactive and organically reactive
grades of special ultra high molecular weight siloxane polymers (>15 million
cSt) with fumed silica. Average particle size, as supplied, is 40 microns (to
minimize dusting). When formulated in a twin-screw extruder in a plastic
formulation, the Siloxane Powders have an average particle size of 2 - 5
microns.
These unique polymers are typically used to improve the flame retardent (FR)
properties and other properties of conventional thermoplastic resins.
Low concentrations (0.1 - 1.0%) of these siloxane powders offer:
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increased compounding efficiency
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improved polymer flow and mold filling
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cycle time reduction
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lower extruder torque
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easier mold release
Levels of 1 - 5% can modify thermoplastic burn characteristics, reducing the
rates of heat release, smoke and carbon monoxide evolution in halogen-free,
halogenated and phosphorus flame retardent (FR) systems.
In highly filled resin systems, siloxane powders can reduce the amount of
solid flame retardent (FR) additive required, improve processability and
restore mechanical properties such as impact strength, which are typically
lost when flame retardent (FR) fillers are added. In unfilled thermoplastics,
siloxane powders at levels up to 15% can significantly enhance impact strength.
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