Hoechst Aktiengesellschaft

Kurt Seiler

Peter Heidel

Helmut Kuhn

There is disclosed a multilayered filter material comprising nonwovens made of fibers or filaments of identical or different polymers, said filter material being composed of a depth filter and a fine filter which both have a homogeneous density perpendicular to their surface and have been joined together in such a way that the area covered by the bonding dots does not exceed 75%. The depth filter is from 2 to 20 times thicker than the fine filter, and they have different densities. There is also disclosed a process for manufacturing the filter material.

Nonwoven material of two or more layers, in particular with long-term

Spunlaid products are provided especially for the manufacture of substrates for polyvinyl chloride coated structured floor coverings. These products consist of crimpfree polyester filaments which are laid down and bonded. Bonding is carried out first by needling at 80 to 300 stitches/cm.sup.2 to a stitch depth of 11 to 20 mm. After needling, impregnation is carried out using a binder liquor consisting of an aqueous dispersion of a copolymer containing

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Abtsteinach, Germany

Kurt Seiler