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AssigneeToyo Seikan Kaisha, Ltd.
InventorsToshinori Moriga, Hiroei Yokota, Toshihiko Tsuchida, Noriyoshi Yano
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A sealing gasket for closure, made of a polyurethane elastomer obtained by reacting the following (A) and (B): (A) a polyisocyanate component having an isocyanate group content of 5 to 38% by weight and average 2 to 3 functional groups, obtained by modifying an aliphatic isocyanate and/or an alicyclic isocyanate, and (B) a polyol component having a hydroxyl value of 20 to 350 mgKOH/g and average 2 to 3 functional groups; and a process for producing a closure using such a sealing gasket. The closure sealing gasket made of a polyurethane elastomer, obtained by the present invention, when used for a closure (e.g. a metal closure of food container), causes no yellowing by ultraviolet light, has a strength at least equal to those of sealing gaskets produced from an aromatic isocyanate and, moreover, excellent rubber properties, is low in dissolution in liquid foods contained in the food container, and promises sufficient sealability. The process for producing a closure according to the present invention is high in productivity and can use the production facilities for other materials such as polyvinyl chloride resin and the like.
A sealing gasket for closure, made of a polyurethane elastomer obtained by reacting the following (A) and (B):
A process for producing a closure, which comprises reacting the following (A) and (B) at the inner side of a closure to synthesize a polyurethane elastomer in such a state that the polyurethane elastomer is integrated with the closure:
A process for producing a closure, which comprises lining the inner side of a closure with the following (A) and (B) and then reacting the (A) and the (B) at 150 to 240° C. for 20 to 200 seconds to synthesize a polyurethane elastomer in such a state that the polyurethane elastomer is integrated with the closure:
Dependencies are inferred from the claim text.