NONWOVEN WEBS HAVING LIQUID IMPERMEABILITY.

摘要

The invention provides a fabric which acts as a barrier to liquids. The fabric may include a substrate having a coating. More particularly, this invention provides nonwoven webs having liquid impermeability; i.e., nonwoven webs having a resistance to penetration by a liquid which impinges the webs. A porous substrate comprising a fabric having pores with a diameter of less than about 12 micrometers and a surface free energy of less than about 40 dynescm is useful in such fabrics. The pore diameter and surface free energy values provide a fabric having (1) a water vapor transmission rate across the fabric greater than about 3000 gm ç24 hours, and (2) a rain impact value of less than about 0.5 g at a hydrostatic head of about 91 cm.