Non-hydrocarbyl hydrophobically modified polycarboxylic polymers

1. A cross-linked carboxylic acid copolymer comprising:

a. recurring units of an olefinic unsaturated carboxylic acid, and

b. recurring units of a non-hydrocarbyl group present in an amount of from about 3 to about 5% by weight of the cross-linked carboxylic acid copolymer,

wherein said copolymer is crosslinked with a di, tri or tetra-functional crosslinker which is present in an amount of from 0.6 to 1.2% by weight such that said cross-linked carboxylic acid copolymer is soluble in water, and the non-hydrocarbyl group comprises a fluorinated hydrophobic monomer.

2. The cross-linked carboxylic acid copolymer of claim 1 wherein the olefinic unsaturated carboxylic acid is selected from the group consisting of acrylic acid, methacrylic acid, ethacrylic acid, alpha-chloro-acrylic acid, alpha-cyano acrylic acid, beta methylacrylic acid (crotonic acid), alpha-phenyl acrylic acid, beta-acryloxy propionic acid, sorbic acid, alpha-chloro sorbic acid, angelic acid, cinnamic acid, p-chloro cinnamic acid, beta-styryl acid (1-carboxy-4-phenyl butadiene-1,3), itaconic acid, citraconic acid, mesaconic acid, glutaconic acid, aconitic acid, maleic acid, fumaric acid, and tricarboxy ethylene.

3. The cross-linked carboxylic acid copolymer of claim 1 wherein the di, tri or tetra-functional crosslinker is selected from the group consisting of butadiene, isoprene, divinyl benzene, divinyl naphthalene, allyl acrylates, trimethylolpropane diallylether, trimethylpropane triacrylate, allyl sucrose, and tetraallyl pertaarythritol ether.

4. The cross-linked carboxylic acid copolymer of claim 1 wherein the di, tri or tetra-functional crosslinker is selected from the group consisting of diallyl esters, dimethallyl ethers, allyl or methallyl acrylates and acrylamides, tetraallyl tin, tetravinyl silane, polyalkenyl methanes, diacrylates, and dimethacrylates, divinyl compounds such as divinyl benzene, polyallyl phosphate, diallyloxy compounds and phosphite esters.

5. The cross-linked carboxylic acid copolymer of claim 1 wherein the di, tri or tetra-functional crosslinker is selected from the group consisting of allyl pentaerythritol, trimethylolpropane diallylether and allyl sucrose.

6. The cross-linked carboxylic acid copolymer of claim 1 wherein the fluorinated hydrophobic monomer comprises fluorinated alkyl methacrylate.

7. The cross-linked carboxylic acid copolymer of claim 6 wherein the olefinic unsaturated carboxylic acid comprises acrylic acid, the di, tri or tetra-functional crosslinker comprises tetraallyl pentaerythritol ether and wherein the fluorinated alkyl methacrylate is present in an amount of about 3 to about 5% by weight of the cross-linked carboxylic acid copolymer.