| 摘要 |
PROBLEM TO BE SOLVED: To provide ultra-high polyethylene foam and to provide a method for producing the same foam, in which the process for removing a liquid plasticizer is not needed and the productivity and strength of the foam are high. SOLUTION: This foam is formed by the following steps: (l) dissolving a nonreactive gas, existing in a gaseous state at the ordinary temperature and pressure, into ultra-high polyethylene resin having a viscosity average molecular weight of >=300,000 at high pressure, in order to make the resin become easy to be molded, followed by kneading it in a molten state in an extruder; (2) feeding the resin in a state easy to be molded into a metal mold at a molten resin pressure equal to or higher than the gas pressure in being dissolved, followed by cooling the resin in a state that the resin pressure is maintained and by extruding the resin at the temperatures ranging from (the crystallization peak temperature-10 deg.C) to (the crystallization peak temperature+5 deg.C) to foam the resin (composition). |
