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US 4,071,494 AGranted
Compatibilization of hydroxyl-containing fillers and thermoplastic polymers
AssigneeChampion International Corporation
InventorNorman G. Gaylord
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AssigneeChampion International Corporation
InventorNorman G. Gaylord
Estimating the term…
Hydroxyl-containing filler reinforced thermoplastic polymers, such as polyolefins, are disclosed having improved physical properties such as impact strength, break strength and flexural modulus. The filler is compatibilized with a thermoplastic polymer containing labile atoms by mixing the two together in the presence of a coupling agent, such as maleic anhydride and a free radical initiator such as a peroxide catalyst. In a preferred embodiment, clay is coated with polyethylene by mixing the two in the presence of a peroxide catalyst and maleic anhydride and the coated filler is then compounded with additional polyethylene. In another preferred embodiment, a filler is coated with a polyolefin having a high melt index and the coated filler is then compounded with a polyolefin having a lower melt index. Also disclosed are various means for molding the compatibilized composites of this invention.
A process for compatibilizing a hydroxyl group containing inorgaic filler with a thermoplastic polymer having labile atoms which provide sites for the formation of free radicals which comprises mixing said filler and said thermoplastic polymer in the presence of an ethylenically unsaturated carboxylic acid or anhydride and a free radical catalyst under conditions which will generate free radicals on the thermoplastic polymer and which will permit the acid or anhydride to react simultaneously with the thermoplastic polymer and the hydroxyl group containing filler, whereby said acid or anhydride reacts with and couples said thermoplastic polymer and said hydroxyl group containing filler to provide a filled thermoplastic polymer composition.
A process for preparing a compatibilized, filled polyolefin composition comprising coating hydroxyl group containing filler particles with a coating of a polyolefin by mixing said particles and said polyolefin in the presence of maleic anhydride or poly(maleic anhydride) and a free radical catalyst under conditions which will generate free radicals on the polyolefin and and which will permit the maleic anhydride or poly(maleic anhydride) to react simultaneously with the polyolefin and hydroxyl group containing filler particles, whereby said polyolefin coating is coupled to said filler, and said polyolefin coated filler particles are thereafter dispersed in a polyolefin matrix, said composition being thermoplastic.
Dependencies are inferred from the claim text.