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US 5,584,923 AGranted
Surface modified calcium carbonate composition and uses therefor
AssigneeECC International Limited
InventorKuan-Ting Wu
Life of this patent
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Abstract
An improved form of calcium carbonate which is acid resistant to enable its use as a filler material in the making of neutral to weakly acid paper, and a process for producing this acid-resistant calcium carbonate is provided. This acid-resistant calcium carbonate comprises calcium carbonate in admixture with at least about 0.5 to about 10 percent, based on the dry weight of the calcium carbonate, of a cationic salt, together with at least about 0.5 to about 10 percent, based on the dry weight of the calcium carbonate, of an anionic salt.
Claims5
A process for the preparation of an acid resistant calcium carbonate which comprises:
- a) forming a mixture of calcium carbonate with at least about 0.5 percent to about 10 percent, based on the dry weight of the calcium carbonate, of a cationic salt;
- b) adding at least about 0.5 percent to about 10 percent, based on the dry weight of the calcium carbonate, of anionic salt to the mixture to form a final mixture;
- and
- c) blending the final mixture to ensure uniform mixing.
1 more element
Dependencies are inferred from the claim text.