| 摘要 |
<P>PROBLEM TO BE SOLVED: To provide a sponge roll for an electrophotographic apparatus, in which an unreacted component after foaming urethane is prevented from precipitating on a surface of a sponge layer and hardening and shrinkage of the sponge layer during foam-molding in a mold is suppressed. <P>SOLUTION: The sponge roll 10 has a sponge layer 14 on an outer circumference of a shaft body 12, the sponge layer being obtained by foaming and curing the following urethane composition in a mold. The urethane composition contains: a polyol component containing the following components a1 to a3, in which a proportion of primary hydroxyl groups in hydroxyl groups of the whole components is 80% or more by a molar ratio; and a polyisocyanate component containing bifunctional isocyanate, in which a proportion of the bifunctional isocyanate in the whole component is 30 mass% or more. The polyol components are: (a1) a polyoxypropylene polyol having a terminal secondary hydroxyl group; (a2) a polyoxypropylene polyol having a terminal primary hydroxyl group introduced by ethylene oxide; and (a3) a polyoxypropylene polyol having a terminal primary hydroxyl group introduced by propylene oxide. <P>COPYRIGHT: (C)2012,JPO&INPIT |
