Container closures and processes of making them
AssigneeW. R. Grace & Co.-Conn.
InventorSteven A. C. White
Life of this patent
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Abstract
Bottle gaskets are provided from a thermoplastic composition comprising a homogeneous blend of butyl rubber with other thermoplastic polymer. The gaskets provide an effective seal at a moderate pressure but permit venting at a higher pressure. They can be made by inserting molten heated thermoplastic material into the bottle cap and moulding it in the cap and cooling it to form the gasket.
Claims11
A sealing gasket comprising a composition formed from a homogeneous blend of from about 20 to about 60% by weight of the blend butyl rubber and from about 40 to about 80% by weight of the blend of one or more thermoplastic polymers, wherein the composition when formed into a gasket in a container closure and applied to a container containing a pressurized potable product forms an effective seal at pressures below 7 bar but which vents at a pressure in a range of 7 to 12 bar.
A sealing gasket comprising a composition formed from a homogeneous blend of from about 20 to about 60% by weight of the blend butyl rubber and from about 40 to about 80% by weight of the blend of one or more thermoplastic polymers selected from the group consisting of polyethylene, polypropylene, thermoplastic rubbers, ethylene propylene copolymers, acid modified ethylene propylene copolymers, stryrene butadiene rubber, carboxylated styrene butadiene, polyisoprene, styrene isoprene styrene block copolymers, styrene butadiene styrene block copolymers, styrene ethylene butylene styrene block copolymers, polystyrene, ethylene vinyl acetate copolymers, ethylene (meth) acrylate coplymers and ethylene vinyl alcohol copolymers wherein the composition when formed into a gasket in a container closure and applied to a container containing a pressurized potable product forms an effective seal at pressures below 7 bar but which vents at a pressure in a range of 7 to 12 bar.
In a container for pressurized products, having a body and a closure with a gasket for sealing the body of the container such that the gasket prevents inward migration of contaminants and unwanted outward escape of gas, the improvement comprising the gasket is formed of a composition formed from a homogeneous blend of from about 20 to about 60% by weight of the blend butyl rubber and from about 40 to about 80% by weight of the blend of one or more thermoplastic polymers, wherein the composition when formed into a gasket forms an effective seal at pressures below 7 bar but which vents at a pressure in a range of 7 to 12 bar.
Dependencies are inferred from the claim text.