Development of Highly Breathable and Effective Blood/Viral Barrier Laminates of Microporous Films, Staple Fibers and Nonwovens

Abstract

In recent years it has been widely known that 3-ply laminates consisting of an inner core of microporous (MP) film and outer layers of spunbond (SB) or meltblown (MB) nonwovens will pass the test for resistance to penetration of synthetic blood (ASTM F 1670); whereas, SB/MB/SB (SMS) laminates will generally not pass this test. Only recently have manufactures begun to make the claim that laminates of MP film with SB and MB nonwovens pass the more rigorous test for resistance to blood-borne virus (ASTM F1671). Nevertheless, laminates developed at the Textiles and Nonwovens Development Center (TANDEC) through sponsorship from Cotton Incorporated, which consistently pass both ASTM F1670 and ASTM F 1671, were first disclosed at INDA-TEC '95. These laminates combine one or more layers of MP film with MB and/or SB webs, as well, but a major difference is that a staple fiber "dry-layer" web is incorporated downstream of the MP film to either absorb (hydrophilic staple fiber webs) or adsorb (hydrophobic staple webs) any minute amount of virus-containing blood that may penetrate the MP film. Since our first disclosure, the mechanisms of this phenomena have been further studied by utilizing dry-layers consisting of thermally bonded 100% polypropylene (PP) staple fiber web that has been scoured (hydrophobic), scoured and plasma treated (hydrophilic), and by using dry-layer blends of 60% cotton/40% hydrophilic (wettable fiber finish) PP.