Polytetrafluoroethylene composites
AssigneeFreudenberg-NOK General Partnership
InventorEdward Hosung Park
Life of this patent
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Abstract
Composites of polytetrafluoroethylene and a structural material (polymer, metal, ceramic, leather, or wood) are bonded with a cured admixture of tetrafluoroethylene-hexafluoropropylene-vinylidene fluoride terpolymer, polyethylene-oxide-modified silicone polymer coupling agent, and oxygen-radical-containing copolymer (epoxy polymer, phenoxy polymer, or hydroxylated diamine-diepoxide derivative copolymer). The bonded surface of the polytetrafluoroethylene portion of the composite is etched (chemical etching, electron-beam etching, laser etching, or plasma etching) prior to application of uncured admixture. The composites are useful in making items such as seals, gaskets, chemically-resistant hoses, o-rings, and pump diaphragms.
Claims19
A method of making a composite, comprising:
- (a) admixing an aqueous admixture of from about 10 to about 90 weight percent fluoropolymer aqueous emulsion and a remainder of oxygen-radical-containing copolymer aqueous solution;
- (b) etching a surface of a polytetrafluoroethylene article to provide an etched surface;
- (c) saturatively distributing said aqueous admixture onto said etched surface;
- (d) positioning a structural material article against said aqueous admixture on said etched surface so that said aqueous admixture fluidly fills an interface between said structural material article and said etched surface, said structural material portion made of a material selected from the group consisting of polymer, metal, ceramic, leather, and wood;
- and
- (e) curing said aqueous admixture in said interface to bond said structural material article to said etched surface;
- wherein said fluoropolymer aqueous emulsion has from about 20 to about 60 weight percent tetrafluoroethylene-hexafluoropropylene-vinylidene fluoride emulsified terpolymer, a pH from about 6 to about 10, a specific gravity from about 1.1 to about 1.5 grams per milliliter, and a viscosity from about 4 to about 12 Mega Pascal Seconds;
- and
- wherein said oxygen-radical-containing copolymer aqueous solution has
- (1) from about 20 to about 60 weight percent oxygen-radical-containing copolymer having a softening temperature of from about 25 to about 180 degrees Centigrade, a specific gravity from about 1.1 to about 1.5 grams per milliliter, and an estimated equivalent molecular weight from about 100 to about 10,000, wherein said oxygen-radical-containing copolymer is an oxygen-radical-containing copolymer selected from the group consisting of epoxy polymer, phenoxy polymer, and hydroxylated diamine-diepoxide derivative copolymer, and
- (2) from about 0.01 to about 1 weight percent polyethylene-oxide-modified silcone polymer coupling agent having a wax melting point of from about 25 to about 45 degrees Centigrade.
Dependencies are inferred from the claim text.