| 摘要 |
A process is claimed for producing filaments and films by incorporating a porogenic agent into a thermoplastic polymer, extruding the polymer melt, subjecting the extruded filament or film to a thermal treatment at >=100 degrees C above the Tg of the polymer while causing >=10% longitudinal shrinkage of the material, and finally cooling the polymer. Porous filaments and films are obtd. without blocking of the extruder die or nozzle, rupture of the extrudate or collapse of the pores occurring as in prior art. Further, by treating the filaments or films prior to the thermal treatment, e.g. with an aqs. soln. of a salt or with functional agents, these can be made to penetrate the pores inside the material to subsequently resist elimination by washing. |
