Ultrafine natural calcium carbonates as coating pigments in coated papers
AssigneePluss-Staufer AG
InventorsPierre Delfosse, Alfred Bosshard
Life of this patent
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Abstract
A coated paper comprising an ultrafine natural calcium carbonate as a pigment, which has an average statistical particle diameter of from 0.5 to 0.7 .mu.m, a maximum diameter of from 3.0 to 4.0 .mu.m, and a specific surface area of at least 12sq.m./g.
Claims13
Paper coated with a composition comprising an ultrafine natural calcium carbonate as a pigment, said pigment having an average statistical particle diameter of from 0.5 to 0.7 .mu.m, a maximum diameter of from 3.0 to 4.0 .mu.m, and a specific surface area of at least 12 sq.m./g.
Paper coated with a pigment composition, comprising a mixture of:
- 70 parts by weight of kaolin;
- and 30 parts by weight of an ultrafine natural calcium carbonate having an average statistical particle diameter of from 0.5 to 0.7 .mu.m, a maximum diameter of from 3.0 to 4.0 .mu.m, and a specific surface area of at least 12 sq.m./g.
Paper coated with a pigment composition comprising a mixture of:
- 25 percent by weight kaolin;
- 25 percent by weight natural calcium carbonate having approximately 35 percent by weight of particles smaller than 2 .mu.m;
- and 50 percent by weight of an ultrafine natural calcium carbonate having an average statistical particle diameter of from 0.5 to 0.7 .mu.m, a maximum diameter of from 3.0 to 4.0 .mu.m, and a specific surface area of at least 12 sq.m./g;
Dependencies are inferred from the claim text.