Coating method and coating slip for substantially inorganic fibrous material

Abstract

A coating slip and a method of coating a fibrous sheet material are disclosed. The coating slip comprises 60-90% by weight pigment consisting of a mixture of talc and soapstone, 10-50% by weight anionic polyelectrolyte, 0-5% by weight thickener, and water in an amount such that the dry solids content of the coating slip will be 60-95% by weight. The weight ratio of talc:soapstone is preferably from about 30:70 to about 70:30, and the talc preferably has a mean particle diameter of about 10-20 .mu.m, while the soapstone preferably has a mean particle diameter of about 5-10 .mu.m. Upon coating, the sheet material is coated on one or both of its sides with preferably about 30-100 g dry material per square meter and side.

Dependencies are inferred from the claim text.