Sealing material for cap and process for producing cap using the same

Abstract

The invention provides a sealing material for caps, e.g., metal caps for food containers, which is reduced in swelling with substances dissolved out or alcoholic beverages and in adsorption of the odor thereof and which comprises a tough and nonyellowing polyurethane elastomer and has satisfactory sealing performance. and to provide a manufacturing method for the lid using the sealing material. The sealing material is made of the polyurethane elastomer that is given by reacting the following elements (A), (B), (C), where (A) is a polyisocyanate element which is given by modifying an aliphatic isocyanate and / or an alicyclic isocyanate, contains isocyanate groups of 5 to 38 mass%, and shows an average functional group number of 2 to 3, (B) is a polyol element which has a hydroxyl group value of 20 to 350 (mgKOH / g) and shows an average functional group number of 2 to 3, and (C) is a fatty acid glycerol ester having hydroxyl groups.

Description

technical field

[0001] The present invention relates to a sealing material for caps comprising a polyurethane elastomer having low swelling property and aroma absorbability especially for alcoholic beverages, and a method for manufacturing a cap using the same. Background technique

[0002] Conventionally, sealing materials for metal lids are often formed of a material mainly composed of vinyl chloride resin because of ease of handling and moldability.

[0003] However, in such sealing materials for metal caps, since the vinyl chloride resin contains a large amount of plasticizers represented by dioctyl phthalate, there is a problem that grease and the like bleed out. This dioctyl phthalate is also a substance suspected of being an environmental hormone. As a solution to this problem, there has been proposed, for example, a sealing material for a metal cap composed of a vinyl chloride resin blended with an acylated ester derivative of a hydroxycarboxylic acid as a plasticiz...

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