| 摘要 |
PURPOSE:To prevent air from remaining in a mold so as to prevent the surface of a sponge roll from having irregularities thereby improving the function and appearance, by not only allowing a gas released when foaming takes place to be discharged simply from through-holes in side plates, but also interposing a gas-permeable sheet between a mold and an unfoamed rubber layer. CONSTITUTION:A roll stem 1 covered with an unfoamed rubber layer 2 is placed in a mold 3 and is secured firmly with the roll stem 1 inserted through holes in side plates 4, 4'. Then the mold 3 is heated by a suitable external heating source such as a hot current to allow the unfoamed rubber layer 2 to foam and to be molded and at the same time to allow the layer 2 to be fused to the roll stem 1 thereby molding a sponge roll in conformity with the inner circumferential surface of the mold 3. Through-holes 5 for discharging the released gas formed in the side plates 4, 4' are in communication with a space 6 formed between the unfoamed rubber layer 2 and the mold 3. Further, a gas-permeable sheet 7 of a heat-resistant non-woven fabric or woven fabric of polyesters, aromatic polyamides, glass fibers or the like, paper or the like is positioned along the inner circumferential surface of the mold 3. The gas resulted from the foaming in the rubber layer near the central part of the roll stem 1 moves along the gas-permeable sheet 7 to be discharged outside of the mold.
|
