Fusible fiber/microfine fiber laminate

A process for preparing a water-impervious, smooth-surfaced, gas-permeable, bacterial barrier, laminated material comprising at least one layer of conjugate fibers, said layer of conjugate fibers having a first face and an opposite face, said conjugate fibers being composed of a lower melting component and a higher melting component, wherein a substantial proportion of the surfaces of said conjugate fibers comprises said lower melting component, said lower melting component of said conjugate fibers which lie on said first face being fuse bonded to at least one hydrophobic ply of microfine fibers having a fiber diameter of up to 50 microns, said lower melting component of said conjugate fibers having been fuse bonded at a temperature below the melt temperature of said higher melting component of said conjugate fibers so that the latter component retains its initial fiber-like integrity, said material being resistant to steam sterilization;

• said process comprising forming an assembly of said ply of hydrophobic microfine fibers and at least one layer of said conjugate fibers placed adjacent to said ply of said hydrophobic microfine fibers;
• subjecting said assembly to smooth calendering at a temperature sufficient to fuse said lower melting component of said conjugate fibers which lie on said first face as well as the ply of the hydrophobic microfine fibers without fusing the higher melting component of said conjugate fibers, direct heat being applied to both outer surfaces of said assembly so that said surfaces are regular and the resultant material has good strength properties;
• cooling said assembly to resolidify said lower melting component of the conjugate fibers as well as said ply of said hydrophobic microfine fibers, whereby said conjugate fibers are firmly bonded to said hydrophobic microfine fiber structure without impairing the integrity of said higher melting component of said fibers and treating said resultant laminated material with a water repellent finish and a repellent binder, or utilizing a layer of conjugate fibers which has been pretreated with a water repellent finish and a repellent binder, before forming said assembly of said ply of microfine fibers and said layer of conjugate fibers.

A process for preparing a water-impervious, smooth-surfaced, gas-permeable, bacterial barrier, lamined material comprising at least one inner ply of hydrophobic microfine fibers sandwiched between two layers of conjugate fibers, each of said layers of conjugate fibers having a first face and an opposite face, said conjugate fibers being composed of a lower melting component and a higher melting component, wherein a substantial proportion of the surfaces of said fibers comprise said lower melting component, said ply of hydrophobic microfine fibers having a fiber diameter of up to 50 microns, said lower melting components of both layers of said conjugate fibers which lie on said first faces having been fuse bonded to said ply of hydrophobic microfine fibers at a temperature below the melt temperature of said higher melting component of said conjugate fibers, so that the latter component retains its initial fiber-like integrity, said material being resistant to steam sterilization;

• said process comprising forming an assembly of said ply of hydrophobic microfine fibers sandwiched between two layers of said conjugate fibers, subjecting said assembly to smooth calendering at a temperature sufficient to fuse said lower melting components of said conjugate fibers which lie on said first faces in both of said layers thereof as well as said ply of said hydrophobic microfine fibers without fusing the higher melting components of said conjugate fibers, direct heat being applied to both outer surfaces of said assembly so that said surfaces are regular and the resultant material has good strength properties;
• cooling said assembly to resolidify said lower melting components of the fibers as well as said ply of hydrophobic microfine fibers, whereby said fibers are firmly bonded to said hydrophobic microfine fibers without impairing the integrity of said higher melting component of said fibers, and treating said resultant laminated material with a water repellent finish and a repellent binder, or utilizing layers of conjugate fibers which have been pretreated with a repellent before forming said assembly of said ply of microfine fibers and said two layers of conjugate fibers.