PURPOSE: To secure can manufacturing workability and quality in can body by carrying out during a canning process the measures of improving adhesion that is deteriorated through multi-drawing process, in reference to the manufacture of two piece cans made of laminated steel sheet especially such as DRD cans or DTR cans.
CONSTITUTION: Multi-drawing is performed by using as the base material a steel sheet laminated with an organic resin film with thermoplastic resin as an adhesion layer. During the multidrawing, the softening point of the thermoplastic resin layer or a heating process for temperatures above the melting point is set. It is desirable that the laminated steel sheet to be laminated is provided with a two layer construction, that the adhesion layer with the steel sheet is composed of a thermoplastic resin with a low melting point and a small crystaliizability, that the non-adhesion layer is of higher melting point than the adhesion layer and is composed of a thermoplastic resin with a large crystallizability. Polyolefin, polyamide, polyester, etc., are available as the resin, but a film in the series of thermoplastic saturated polyester resin is desirable in point of heat resistance, mechanical property, anti-corrosion performance, flavor and other aspects of general performance.
NISHIDA HIROSHI
YOKOYA HIROICHI
