| 摘要 |
PURPOSE:To improve weathering resistance by a method in which after polyolefin resin has been laminated on a steel sheet, electron beam is radiated onto said polyolefin resin surface from the side thereof in oxygen atmosphere, and then methacrylic acid methyl is brought in contact with said resin. CONSTITUTION:After polyolefin resin has been laminated on a steel sheet, the electron beam of 3-30Mrad is radiated onto the surface of the polyolefin resin from the side thereof in the atmosphere of oxygen concentration less than 500ppm, and then methacrylic acid methyl is brought in contact with the polyolefin resin. Since the polyolefin resin becomes a crosslinked three dimensional structure when electron beam is radiated, the oxidation and the molecule cutting due to ultraviolet ray are remarkably suppressed, and the occurrence of cracks is decreased. Since radical is generated simultaneously with the radiation of electron beam, when it is brought in contact with methacrylic acid methyl, methacrylic acid methyl infiltrates in the skin layer, and said radical is graft-polymerized. Further, methacrylic acid methyl is also polymerized and becomes polymethacrylic acid methyl, whereby coloring and crack occurrence are suppressed. Accordingly the weathering resistance of a laminated steel sheet can be improved. |
