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AssigneeTri-Seal International, Inc.
InventorsHarvey Finkelstein, Victor Flores, Murray Singer, Anatoly Verdel
Estimating the term…
A cap liner and method for producing a cap liner which is particularly suited for use with a cap employed on a hot filled container. The liner includes a disc having one or more outer layers and an intermediate foamed layer bonded thereto. Preferably, the outer layer is formed of a copolymer of polypropylene and polyethylene. The intermediate layer can include a homogeneous admixture of polypropylene and polyethylene or an admixture of polyethylene, a copolymer of polyethylene and polypropylene and ethylene vinyl acetate. One method for producing the cap liner involves mechanically mixing at room temperature polypropylene and polyethylene to form a desired homogeneous admixture for each layer, and then co-extruding the admixtures at approximately 320.degree.-415.degree. F. to form the bonded outer and intermediate layers. Another method involves extruding the copolymer outer layer to the intermediate layer admixture to form the bonded cap liner. Alternatively, the intermediate layer may be formed of foamed polyethylene.
Closure liner for a container having a neck portion and a rim portion which defines a container opening, said closure liner comprising a cap which is operable to be received on the neck portion, a cap liner positioned inside said cap comprising a disk having a pair of outer layers and an intermediate layer sandwiched between said outer layers and co-extruded thereto, said outer layers comprising a substantially homogenous admixture of polyethylene and 10-98% by weight of polypropylene and said intermediate layer is a resilient foamed admixture comprising 15-40% by weight low density polyethylene, 15-40% ethylene vinyl acetate, and 15-40% of a copolymer of 10-90% polyethylene with the balance polypropylene, said liner being positioned in said cap such that when said cap is positioned on the neck portion, one of said outer layers is positioned against an inside top portion of said cap, the other outer layer engages the container rim portion and covers the opening, and said intermediate layer is compressed to provide an effective seal between said cap liner and the container which does not structurally or functionally degrade when exposed to heat from a hot filled container.
A method of manufacturing a cap liner having a first layer of polypropylene and polyethylene, extruding a homogenous admixture of 10-98% polypropylene with the balance polyethylene to form the first layer and simultaneous extruding a second foamed layer with said first layer to form said cap liner, said second foamed layer including polyethylene for bonding to said first layer, said second foamed layer further comprising one of a second substantially homogenous admixture comprising 10-98% by weight of polypropylene with the balance polyethylene and a third substantially homogenous admixture of 15-40% ethylene vinyl acetate, 15-40% low density polyethylene and 15-40% of a copolymer of 10-90% polyethylene with the balance polypropylene.
Dependencies are inferred from the claim text.