| 摘要 |
PROBLEM TO BE SOLVED: To save on the trouble to remove or recover an organic solvent and enhance the productivity by dissolving a gas which is in a vapor phase at a normal temperature and a normal pressure into an ultrahigh molecular weight polyethylene with a specific viscosity- average molecular weight under a high pressure and at the same time, exposing it to a lower atmospheric pressure than a pressure at the time of dissolution while maintaining the polyethylene at a specific temperature after heating it up above a melt point. SOLUTION: A gas which is in a vapor phase at a normal temperature and a normal pressure is heated up above a melt point while dissolving the gas into an ultrapolymeric polyethylene with 300,000 or more viscosity-average molecular weight under a high pressure. Then after melting it, the polyethylene is exposed to a lower atmospheric pressure than a pressure at the time of dissolution while maintaining a crystallization peak temperature below -10 deg.C when the temperature drops. The method for manufacturing an ultrahigh molecular weight polyethylene porous body is to supply the pellets of the ultrahigh molecular weight polyethylene to the solid conveyance part 23 of a barrel 21 from a pressure-resistant hopper 3 and feed a high pressure gas from a gas feed aperture 25. Further, the gas is dissolved into the polyethylene while the gas is conveyed in the direction of a cylinder part 24. After that, the gas is supplied from a gas feed aperture 26 to be dissolved into the polyethylene, which is in turn, fused by heat. This molten polyethylene is extruded in a pipelike from a mold 4 to obtain moldings 7. |
