Toyo Kohan Co., Ltd.

Fumiko Gotoh

Atsuo Tanaka

Hiroyuki Iwashita

The present invention relates to a polyester resin-covered metal sheet exhibiting superior formability and particularly suitable to withstand the stresses of drawing, drawing and ironing, drawing and stretch forming, or drawing and stretch forming followed by ironing. The resin-covered metal sheet is produced by contacting a biaxially oriented polyester resin film to a metal sheet heated above the melting temperature of the resin, covering the metal sheet with the polyester resin, pinching and press laminating the film-metal sheet composite, and cooling the laminate at a rate of 600&deg; C./second immediately thereafter. It is essential that the resulting resin-covered metal sheets exhibit a true stress of 3.0 to 15.0 kg/mm , corresponding to a true strain of 1.0 at 75&deg; C. These laminates also exhibits a gradation of retention of the polyester resin's original biaxial orientation. Portions of the resin farthest from the metal sheet retain the greatest degree of their original orientation, the resin structure becoming increasingly amorphous nearer the underlying metal sheet.

Metallic sheet covered with polyester resin film and having high workability, and method of manufacturing same

The present invention produces a polyethylene terephthalate resin covered metal sheet having extremely excellent formability, which can be available for uses in which severe forming is practiced such as drawing, drawing and ironing and drawn and stretch forming as well as the composite forming consisting of drawn and stretch forming followed by ironing. A biaxially oriented film consisting of polyethylene terephthalate resin having a low temperature crystallization temperature ranging from 130&deg; C. to 165&deg; C. is covered at least on one side of a metal sheet by heat bonding in the way that the biaxial orientation of the film of the polyethylene terephthalate resin after being covered is gradually increasing from the contacting portion of the film to the metal sheet to the surface portion of the film.

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Yamaguchi-ken, Japan

Fumiko Gotoh