| 摘要 |
Commercially available plastic resin that has been stored in ambient air is contacted with an oxygen-depleted atmosphere to reduce the absorbed oxygen level in the resin, then extrusion molded into the desired shape. The resin can be initially blown against the mold using air, but preferably is blown using an inert gas at or near ambient temperature. Immediately following the blowing step, the inert gas is use to pressurize and flush the molded resin, followed by depressuring the molded product and releasing it from the mold. A second embodiment employs molds kept at a temperature between about 50° F. and 150° F., and the inert gas used to pressurize and flush the molded resin is at a temperature below about 0° F.
|
