Can lid for resin metal composite containers, which is formed of resin laminated steel sheet, can bottom for resin metal composite containers, which is formed of resin laminated steel sheet, and resin metal composite container

Abstract

This can lid for resin metal composite containers, which is formed of a resin laminated steel sheet, is provided with a top board part and a curved part that is positioned on the outer circumference of the top board part; and the resin laminated steel sheet comprises a steel sheet, a thermoplastic polyester resin layer that is provided on a first surface, a modified polypropylene resin layer that is provided on a second surface, a polypropylene resin layer and an ethylene-propylene copolymer resin layer. With respect to the resin laminated steel sheet, the melting point of the ethylene-propylene copolymer resin layer is from 135DEG C to 150DEG C (inclusive); the melting point of the thermoplastic polyester resin layer is higher than the melting point of the polypropylene resin layer by 40DEG C or more; and the ratio of the ethylene component in the ethylene-propylene copolymer in the ethylene-propylene copolymer resin layer ranges from 1.0% by mass to 45.0% by mass (inclusive).

Description

technical field [0001] The present invention relates to a can lid made of resin-laminated steel plate for a resin-metal composite container, a tank bottom made of resin-laminated steel plate for a resin-metal composite container, and a resin-metal composite container. Resin-laminated steel plate can lids for resin-metal composite containers with thermoplastic resin as the can body, resin-laminated steel plate bottoms for resin-metal composite containers, and resin-metal composite containers with polypropylene-based thermoplastic resin as the can body . This application claims priority based on Japanese Patent Application No. 2019-020682 for which it applied in Japan on February 7, 2019, and uses the content here. Background technique [0002] At present, as containers for long-term storage of food, food cans including a metal can body, can lid, and can bottom are the mainstream. However, since the contents of metal cans cannot be seen unless the cans are opened, in recent y...

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Problems solved by technology

[0006] The laminated metal composite container with plastic easy-open lid shown in Patent Document 1 needs to form a pull ring for plastic easy-pull on the outer surface of the lid, so it needs The polypropylene layer is formed on the resin laminate outer layer of the lid, and there is a disadvantage that traces of heating jigs for heat sealing tend to remain in the outer surface film when the lid and the can body are heat-sealed.

In addition, since the joint between the can body flange and the lid is made of polypropylene resin, the temperature at the time of joining may be low, or if the heating time is short, the fusion bonding may become uneven, and the airtightness may not be stable. subject

[0007] In addition, the problem with metal cans is that the contents cannot be confirmed from the appearance, and the problem with retort pouch containers is that the strength of the container itself is low and it is not suitable for long-term use. To preserve this, in recent years, a resin-metal composite type container has been proposed, in which, in Figure 19 uses thick transparent to semi-transparent thermoplastic resin for the can body, and sets the can lid to be made of resin-coated steel plate

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