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Fluoropolymer Glass-Microsphere Composites

IP.com Disclosure Number: IPCOM000183849D
Publication Date: 2009-Jun-02
Document File: 1 page(s) / 22K

Publishing Venue

The IP.com Prior Art Database

Abstract

Degradation of glass bubble filled fluoropolymer composites can be mitigated by coating the glass microsphere with either a pacifying agent, for example, an acid,and/or an encapsulating material, for example, a silane. The fluoropolymer may be a thermoplastic, a thermoset, or an elastomer.

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Fluoropolymer-Glass Microsphere Composites

Degradation of glass bubble filled fluoropolymer composites can be mitigated by coating the glass microsphere with either a pacifying agent, for example, an acid, and/or an encapsulating material, for example, a silane. The fluoropolymer may be a thermoplastic, a thermoset, or an elastomer.

Thermally formed glass microspheres typically contain 70 - 80 weight % SiO2, 3 - 8 weight % Na2O, 8 - 15 weight % CaO and 2 - 6 weight % B203. During the bubble forming stage metal oxides migrate to the surface of the microsphere as it condenses. This may significantly change the pH of the microspheres.

Fluoropolymers that contain acidic hydrogen ions such as PVDF (polyvinylidene fluoride), THV (a terpolymer consisting of tetrafluoroethylene, hexafluoropropylene and vinylidene fluoride), VDF/HFP (vinylidene fluoride/hexafluoropropylene) copolymers, and in general fluoropolymers (homopolymers or copolymers) containing VDF (vinylidene fluoride) monomer, are sensitive to alkaline conditions. Consequently, blending alkaline materials such as glass microspheres into fluoropolymers will cause dehydrofluorination, chain scission and unsaturation. Depending on the type of fluoropolymer and reaction conditions, the Melt Flow Rate (MFR) will change and may result in discoloration, turning the clear or white composite yellow, tan, or even brown. Coating the microsphere with a mineral or organic acid, such...