| 摘要 |
PURPOSE:To easily remove a seal ink undried remaining on a seal impression, by using a cleaning material containing a butyl rubber as a main constituent together with a copolymer of isobutylene and n-butene and a copolymer of an olefinic unsaturated hydrocarbon and a diolefinic unsaturated hydrocarbon. CONSTITUTION:50-90pts. of a butyl rubber having a degree of unsaturation of 0.6-2.0 and a Mooney viscosity of 41-49, 10-20pts. of a copolymer of isobutylene and n-butene and 10-40pts. of a thermoplastic resin consisting of a copolymer of an olefinic unsaturated hydrocarbon and a diolefinic unsaturated hydrocarbon are mixed with each other at a temperature of not higher than 100 deg.C to obtain a cleaning material which is not sticky to the touch and is a soft elastic solid at normal temperature. By repeatedly pressing a seal impression against the thus obtained cleaning material and separating therefrom for several times, the seal ink undried remaining on the seal impression can be easily removed. |
