Aqueous dispersion of gypsum and its use as a filler and coating pigment in the production of paper and cardboard
First Claim
1. An aqueous dispersion comprising gypsum and a surface-active, anionic compound, wherein said surface-active compound is a phosphoric acid ester selected from the group consisting of (1) an acidic phosphoric acid ester of the formula:
- ##STR3## wherein R1 and R2 are the same or different and are alkyl poly(oxyethylene), alkyl poly(oxypropylene), alkylphenoxyalkyl or alkylphenyl polyoxyalkyl radicals, (2) a monophosphoric acid ester of a monoor dihydroxyalkylurea or of an alkoxylated mono- or dihydroxyalkylurea, and (3) a phosphoric acid ester of a poly-alkoxylated amine, in which one or more hydroxyl groups are are be esterified with phosphoric acid.
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Abstract
The present invention provides an aqueous dispersion comprising gypsum and a surface-active, anionic compound, wherein the surface-active compound is a phosphoric acid ester selected from the group consisting of (1) an acidic phosphoric acid ester of the formula: ##STR1## wherein R1 and R2 are the same or different and are alkyl poly(oxyethylene), alkyl poly(oxypropylene), alkylphenoxy- alkyl or alkylphenyl polyoxyalkyl radicals, (2) a monophosphoric acid ester of a mono- or dihydroxyalkylurea or of an alkoxylated mono- or dihydroxyalkylurea, and (3) a monophosphoric acid ester of a polyalkoxylated amine, in which several hydroxyl groups can be esterified with phosphoric acid.
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24 Claims
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1. An aqueous dispersion comprising gypsum and a surface-active, anionic compound, wherein said surface-active compound is a phosphoric acid ester selected from the group consisting of (1) an acidic phosphoric acid ester of the formula:
- ##STR3## wherein R1 and R2 are the same or different and are alkyl poly(oxyethylene), alkyl poly(oxypropylene), alkylphenoxyalkyl or alkylphenyl polyoxyalkyl radicals, (2) a monophosphoric acid ester of a monoor dihydroxyalkylurea or of an alkoxylated mono- or dihydroxyalkylurea, and (3) a phosphoric acid ester of a poly-alkoxylated amine, in which one or more hydroxyl groups are are be esterified with phosphoric acid.
- View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24)
Specification