Toyo Boseki Kabushiki Kaisha

Hideki Igushi

Hiroshi Nagano

Hideki Shimizu

Tsutomu Oko

Katsuaki Kuze

Tsutomu Isaka

Shingo Fujii

A polyester film which shows, upon preparation of a film-laminated metal plate by laminating the film of one side of the metal plate made of a tin free steel, a coefficient of kinetic friction at 80 degrees Celsius at the surface thereof of not more than 0.45 and an ethylene terephthalate cyclic trimer content of not more than 0.7 wt %, and a dimensional change of not more than 2.0% after a heat treatment at 210 degrees Celsius for 2 minutes of the film laminated metal plate. This polyester film is superior in heat resistance, barrier property and corrosion resistance, and is preferably used as a material forming a metal container for food.

Polyester film for metal plate laminate, film-laminated metal plate and metal container

The present invention provides a white biaxially oriented polyester film having a two-layer structure of layer A/layer B, wherein the layer A contains a polyester having a melting point of 240&deg; C.-260&deg; C. and containing titanium dioxide in a proportion of 5-30 wt %, the layer B contains a polyester having a melting point of 210&deg; C.-235&deg; C., and the film shows a dimensional change of not more than 2%, which is obtained by thermally adhering a layer B side of the film to a metal plate to give a laminate, which is heat-treated at 210&deg; C. for 2 minutes, and subjecting the film after the treatment to the measurement, a film-laminated metal plate using the polyester film and a metal container obtained by forming this film-laminated metal plate. The polyester film of the present invention has superior heat resistance and is capable of stably covering the surface of a metal plate even after a heat treatment during a can forming process and the like.

White polyester film for metal plate laminate, film-laminated metal plate and metal container

A polyester laminate film comprising plural polyester layers, which comprises one surface layer comprising a polyester and a lubricant having an average particle size of 1-3 &mgr;m in a proportion of 1-5 wt % and the other surface layer comprising a polyester wherein 5-15 mol % of the entire acid component is a dimer acid component, the polyester laminate film having a crystallization peak temperature of 80-120&deg; C. under temperature rise of the On The polyester laminate film of the present invention has a lower crystallization peak temperature when the film is under temperature rise, as compared to conventional polyethylene terephthalate. As a consequence, the film is free of whitening upon retorting, even after the film was subjected to remelting treatment and rapid cooling for noncystallization and unorienting. Therefore, the film serves well as a laminate film for food containers and beverage cans that undergo retort sterilization. Inasmuch as the polyester layer on one surface contains a large amount of a lubricant and has releasing property, the film serves well as a laminate film for a metal plate, which is required to have releasing property from a mold during manufacture of containers such as a two-piece can. The polyester layer on the other surface contains a large amount of dimer acid and the film is superior in impact resistance. Hence, the film serves well as a laminate film for a metal container which is susceptible to damage due to impact during distribution process.

Polyester laminate film, metal plate laminated with this film and film-laminated metal container

A polyester laminate film comprising plural polyester layers, which comprises one surface layer comprising a polyester and a lubricant having an average particle size of 1-3 &mgr;m in a proportion of 1-5 wt % and the other surface layer comprising a polyester wherein 5-15 mol % of the entire acid component is a dimer acid component, the polyester laminate film having a crystallization peak temperature of 80-120&deg; C. under temperature rise of the film The polyester laminate film of the present invention has a lower crystallization peak temperature when the film is under temperature rise, as compared to conventional polyethylene terephthalate. As a consequence, the film is free of whitening upon retorting, even after the film was subjected to remelting treatment and rapid cooling for noncrystallization and unorienting. Therefore, the film serves well as a laminate film for food containers and beverage cans that undergo retort sterilization. Inasmuch as the polyester layer on one surface contains a large amount of a lubricant and has releasing property, the film serves well as a laminate film for a metal plate, which is required to have releasing property from a mold during manufacture of containers such as a two-piece can. The polyester layer on the other surface contains a large amount of dimer acid and the film is superior in impact resistance. Hence, the film serves well as a laminate film for a metal container which is susceptible to damage due to impact during distribution process.

A laminating film for a metal sheet, which comprises a thermoplastic resin and which is free of a pinhole having a diameter of not less than 0.1 mm .phi. at least in the portion laminated on the metal sheet, a metal sheet prepared by laminating this film, and a metal container formed from this metal sheet. The film of the present invention is superior in corrosion resistance, flavor resistance and printability. Hence, the metal sheet and metal container of the present invention have beautiful appearance and high food protection effect.

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Inuyama, Japan

Hideki Igushi