Resin-coated metal sheet for can lid

Abstract

A resin-coated metal sheet for a can lid is configured by: heat sealing a thermoplastic resin film A on a surface to be the exterior surface side of a can lid made of a metal sheet (1), the thermoplastic resin film A principally containing PBT and PET; and heat sealing a thermoplastic resin film B on a surface to be the interior surface side of the can lid, the thermoplastic resin film B principally containing PBT. In the thermoplastic resin film A, the PBT / PET composition ratio is (40 / 60)-(80 / 20) in terms of percentage by weight, and the ratio of the Raman band intensity (I0) at 1615+ / -10 cm-1 in the horizontal plane of polarization with respect to the surface and the Raman band intensity I90 at 1615+ / -10 cm-1 in the vertical plane of polarization with respect to the surface is 0.60 or higher. The thermoplastic resin film (B) has a PET content of 95% (molar) or more. The melting point resulting from the PET in the thermoplastic resin film B is 250 to 265 degrees centigrade and is at least 25 degrees centigrade higher than the melting point resulting from the PBT in the thermoplastic resin film A. The half-value width of the Raman band at 1730+ / -10 cm-1 in the horizontal plane with regard to the surface is 15-20 cm-1.

Description

technical field [0001] The present invention relates to a resin-coated metal plate for can lids mainly used for lids of food cans. Background technique [0002] Conventionally, solvent-based coatings mainly composed of thermosetting resins have been coated on the inner and outer surfaces of metal beverage cans and food cans. Its purpose is to maintain the flavor of the contents, prevent metal corrosion as the material of beverage cans and food cans, improve the design of the outer surface of beverage cans and food cans, protect the printed surface, etc. However, solvent-based paints require heating at high temperatures in order to form a coating film, and since a large amount of solvent is generated during heating, there are problems in terms of work safety and influence on the environment. Therefore, recently, as a corrosion prevention method not using a solvent, coating of a metal with a thermoplastic resin has been proposed. In particular, among thermoplastic resins, po...

AI Technical Summary

Problems solved by technology

However, when the high-melting-point side film is laminated at high temperature, not only the interface between the low-melting-point side film and the metal plate, but also the entire layer of the low-melting-point side film melts, and sometimes the low-melting-point side film adheres to the bonding film. Defective condition of the roller (welding)

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