Method for production of a polyethylene laminated metal sheet
AssigneeToyo Kohan Co., Ltd.
InventorsTakaaki Okamura, Atsuo Tanaka, Tsuneo Inui, Akio Miyachi
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Abstract
A polyethylene film is heat bonded to a metal sheet provided with a layer of hydrated chromium oxide, and possibly a layer of metallic chromium under the oxide layer. The laminated metal sheet is then rapidly quenched, and the polyethylene laminate is irradiated with an electron beam, gamma rays, or X-rays. Alternatively, the polyethylene film may be irradiated prior to lamination. The laminated metal sheet exhibits excellent resistance to steam and hot water and does not delaminate during forming operations such as can-making.
Claims29
A method for producing a metal sheet laminated with a polyethylene film comprising
- providing a metal sheet with chromium layer means consisting of one of a single layer consisting of a layer of hydrated chromium oxide and a double layer consisting of a lower layer of metallic chromium and an upper layer of hydrated chromium oxide,
- heating said metal sheet with said chromium layer means thereon to a temperature of Tm to Tm+240.degree. C., where Tm is the melting temperature of the polyethylene film,
- exposing a surface of a polyethylene film having 70 to 100 mole % of ethylene units to an oxidation treatment sufficient to produce a wetting index in the range of 38 to 54 dyne on said surface,
- laminating said surface of said polyethylene film directly to said chromium layer means on at least one side of said metal sheet,
- quenching said metal sheet with said laminated polyethylene film, and
- irradiating said polyethylene film with 1to 25 kilocoulomb/kilogram of a radioactive ray.
A method for producing a metal sheet having one side laminated with a polyethylene film and another side laminated with a polyester resin film, comprising
- providing a metal sheet with chromium layer means consisting of one of a single layer consisting of a layer of hydrated chromium oxide and a double layer consisting of a lower layer of metallic chromium and an upper layer of hydrated chromium oxide,
- heating said metal sheet with said chromium layer means thereon to a temperature of T to T+160.degree. C., where T is the melting temperature of the polyester resin film,
- exposing a surface of a polyethylene film having 70 to 100 mole % of ethylene units to an oxidation treatment sufficient to produce a wetting index in the range of 38 to 54 dyne on said surface,
- laminating said surface of said polyethylene film directly to said chromium layer means on one side of said metal sheet,
- simultaneously laminating said polyester resin film to the other side of said metal sheet,
- quenching said metal sheet with said laminated polyethylene film and said laminated polyester film, and
- irradiating said polyethylene film with 1 to 25 kilocoulomb/kilogram of a radioactive ray.
Dependencies are inferred from the claim text.