| 摘要 |
PURPOSE:To utilize a feature of a polyvinyl chloride covered copper plate and to improve an anti-contamination characteristic by a method wherein a covering sheet composed of an acrylic resin layer at its surface and a polyvinyl chloride resin layer at its intermediate layer is applied to cover a metallic plate. CONSTITUTION:A covering sheet covering a metallic plate is comprised of a polyvinyl chloride PVC acting as an inner layer and an acrylic resin layer acting as an outer layer. As the PVC layer, material to be used normally in the metallic plate is satisfactory and a sheet having a hard characteristic, semi-hard characteristic or soft characteristic can be used. The acrylic resin layer is disposed for improving an anti- contamination characteristic and one formed similarly into a sheet shape as that of PVC layer can be used. A piling-up of the PVC layer and the acrylic layer may be carried out prior to a covering to the metallic plate or they can be piled up in sequence on the metallic plate. Since acrylic resin can be melted and adhered together with PVC, no adhesive agent may not be used in particular between both layers. As acrylic resin, polymethylmethacrylate may be used and it is preferable to use a co-polymar with a small amount of acrylic acid ester, for example, butyl acrylate. It is possible to make a substantial improvement of anti-contamination while some features of the PVC coated plate are being kept. |
