W. R. Grace Co.-conn.

W. R. Grace & C.-conn.

Steven A White

Robert H Hofeldt

Robert M Hofeldt

A gasket for a crown cap to be used on a carbonated beverage, especially a twist-off crown or for a bottle which is to be pasteurized, is formed of a thermoplastic material, which is preferably free of polyvinyl chloride, and which contains a hydrogenated copolymer of styrene and a conjugated diene, or a functionalized derivative thereof. The material is resistant to heat, and provides a gasket with advantageous sealing properties.

Gasket composition for crown caps

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.

Container closures and processes of making them

A sealing composition for a container closure comprising a polymeric matrix material and is modified by the inclusion therein of an oxygen scavenger. The composition can be in fluid or meltable form ready for application to a closure or it can be present as a deposit on the closure, for instance a gasket around the closure. Preferably the scavenging properties of the deposit are activated by pasteurizing or sterilizing the deposit when sealing a container with the closure. The invention is of particular value when the closure is a metal cap for a beer bottle.

Sealed containers and sealing compositions for them

A container system for beer formed of a bottle body, a cap and sealing gasket formed of a blend of butyl rubber and one or more thermoplastic polymers. Preferably, the butyl rubber is present in an amount of from about 20 to about 60% by weight of the composition and the one or more thermoplastic polymers are present in an amount from about 40% to about 80% by weight of the composition. The system provides good sealing properties and prevents oxygen, and chlorinated substances such as chlorinated phenols or anisoles, that may be present in the packaging, from entering the bottle.

Containers and compositions for sealing them

A package formed of a wooden crate or pallet impregnated with a chlorinated phenol and/or anisole wood preservative, one or more bottles containing a potable material, such as beer, a cap on each bottle and a sealing gasket between the bottle and the cap. The gasket is formed of butyl rubber (20 to 80% by weight) and one or more thermoplastic polymers, preferably polyethylene (40 to 60% by weight).

A sealing composition for a container closure comprises a polymeric matrix material and is modified by the inclusion therein of an oxygen scavenger. The composition can be in fluid or meltable form ready for application to a closure or it can be present as a deposit on the closure, for instance a gasket around the closure. Preferably the scavenging properties of the deposit are activated by pasteurizing or sterilizing the deposit when sealing a container with the closure. The invention is of particular value when the closure is a metal cap for a beer bottle.

Molded articles such as gaskets for container caps are made from a thermoplastic composition at high speed, for instance above 100 per minute, by continuously cutting a continuous supply of molten thermoplastic composition into molten pieces and transferring the molten pieces to a molding position at which they are molded into the gaskets or other desired articles, and the composition includes a melt-release material that continuously replenishes a melt-release layer on the surfaces by which the molten composition is cut and transferred to the molding position.

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Ivinghoe, United Kingdom

Steven A White