| 摘要 |
PROBLEM TO BE SOLVED: To uniformly stabilize the electric resistance value over the whole surface of a roll and minimize the wrinkling by covering a core material having a necessary strength with a semiconductive seamless tube of a synthetic resin containing resin-coated carbon black. SOLUTION: As the base resin of the seamless tube, polypropylene or epoxy resin is used, and as the core material, a metallic bar or cylinder of a material having a strength necessary for retaining the form of a roll such as stainless steel, aluminum alloy or the like is used. In the covering, the resin solution is added to a water slurry of carbon black little by little with stirring, and the solvent and water are removed by vacuum drying after draining to provide a resin-coated carbon black. This is then mixed with a thermoplastic resin followed by kneading to pellet the mixture, which is then extrusion molded to form a seamless tube, and the tube is fitted onto the core material. Since the change of resistance value accompanied by the increase in mixing quantity of the resin-coated carbon black is moderate, the control is facilitated. According to this, a roll stabilized in electric resistance in a semiconductor area of 1013-104Ω.cm can be provided. |
