| 摘要 |
PROBLEM TO BE SOLVED: To provide a rubber sponge tube having a high rotary torque resistance and a low specific gravity, and a high quality of rubber sponge roll having fine uniform foaming cells without huge foamed cells on a grinding face. SOLUTION: A rubber sponge tube for a roll is so constituted that it has a skin layer at the inside and outside faces and an average foaming cell diameter is enlarged gradually from the tube inside and outside faces to the center direction of the thick wall in the tube section and the maximum foaming cell exists within 20-60% of the tube wall thickness from the inside of the tube section to the outside. It is preferable that the chief component of the rubber sponge tube is ethylene-polypropylene rubber. Further, a core shaft body is inserted in the rubber sponge tube, and the average foaming cell diameter of polished surface the external face of which is ground is 200μm or smaller and any huge foaming cell does not exist in the rubber sponge roll. |
