摘要 |
<p>The present invention relates to breathable, waterproof sheet materials comprising a microporous polymeric film and a hydrophilic filler material infiltrated into the pores of the film, and to methods for making such sheet materials. In the methods of the present invention, the liquid hydrophilic material or precursor thereof is infiltrated into the pores of the microporous film after the film has been stretched in the lengthwise direction, but before the film is stretched in the transverse direction. By coating the microporous film prior to the transverse stretching step, superior waterproof sheet materials are obtained.</p> |