PROCEDE POUR LA PREPARATION D'UN MATERIEL PLAN MULTICOUCHES

摘要

This invention relates to a process for the production of a gas-permeable multilayer sheet material, and to the material so produced, the process comprising applying a liquid layer of a solution of a polymer in a water-miscible solvent to the surface of a moving web of fiber fleece which is free from chemical binders and allowing part of the solution to penetrate into the fleece; incorporating an aqueous dispersion of synthetic material in the fleece from the uncoated surface thereof, the dispersing phase of the dispersion acting as a coagulating agent upon part of the polymer solution contained in the fleece; causing a coagulating agent to act upon the liquid layer of polymer solution on the surface of the fleece, upon the still uncoagulated portion of the polymer solution in the fleece, and upon the dispersion of synthetic material contained in the fleece; removing any excess of coagulating agent and solvent, and drying the multilayer sheet material.