Cationic polymers for treating construction aggregates
View Patent ↗The present invention provides methods, admixture compositions for treating clay-bearing aggregates used for construction purposes, and aggregate compositions for construction purposes. The clay-bearing aggregates are treated with a cationic copolymer made from two and preferably three different monomer components. Cementitious compositions containing the treated aggregates are also described.
1. A method for treating clay-bearing sand aggregates used in construction materials, comprising:
introducing to clay-bearing sand aggregates, in an amount of 3% to 60% based on weight of clay treated, at least one copolymer obtained by copolymerizing monomer components (A), (B), and (C), as follows:
(A) in an amount of 60-98 mol percent, a cationic monomer selected from quaternized vinyl pyridine and other cationic monomer represented by the following structures
wherein
R 1 , R 2 , and R 3 each independently represent hydrogen, —CH 3 , or —COOH;
R 4 , R 5 , R 6 , R 7 , and R 8 each independently represent a C 1 -C 4 alkyl group;
R 9 and R 10 each independently represent hydrogen or —CH 3 ;
Z 1 represents —O— or —NH—;
Y 1 represents —CH 2 CH(OH)CH 2 — or C 1 -C 6 alkyl group; and
X represents a halide, pseudohalide, or sulfate;
(B) in an amount of 2-40 mol percent, a hydrophobic, essentially water-insoluble monomer selected from the group consisting of vinyl acetate, styrene and its derivatives, vinyl ethers of formula CH 2 ═CH—O—R 11 in which R 11 is a linear or branched, saturated or unsaturated hydrocarbon radical from 1 to 12 carbons, and esters of formula H 2 C═CR 12 —CO—Z 2 —R 13 in which R 12 is hydrogen or C 1 to C 3 alkyl, Z 2 is —O—, and R 13 is a linear or branched, saturated or unsaturated hydrocarbon radicals having from 1 to 18 carbons; and
(C) in an amount of greater than 1 and no greater than 20 mol percent, a water-soluble monomer selected from the group consisting of acrylamide, methacrylamide, alkyl acrylamide, dialkyl acrylamide, alkyl methacrylamide, dialkyl methacrylamide, polyalkyleneoxide acrylate, polyalkyleneoxide methacrylate, and polyalkyleneoxide ether.
2. The method of claim 1 wherein said copolymer has a molecular weight of 1,000-100,000.
3. The method of claim 2 , wherein said copolymer has a molecular weight of 2,000-60,000.
4. The method of claim 3 , wherein said copolymer has a molecular weight of 5,000-50,000.
5. The method of claim 1 wherein the molar ratio (A:B) of said first monomer component (A) to said second monomer component (B) is 0.80:0.20 to 0.98:0.02.
6. The method of claim 1 wherein each of R 7 and R 3 are —CH 3 groups, and each of R 9 and R 10 are hydrogen.
7. The method of claim 1 wherein Y 1 is —CH 2 CH 2 —.
8. The method of claim 1 wherein said copolymer has two or more monomer components which are represented by said structures of said first monomer component (A).
9. The method of claim 1 wherein said copolymer has two or more monomer components which are represented by said structure of said monomer component (B).
10. The method of claim 1 wherein the amount of said copolymer introduced to said clay is 5% to 40% by weight based on the weight of said clay.
11. The method of claim 1 wherein the amount of said copolymer introduced to said clay is 8% to 20% by weight based on the weight of said clay.
12. The method of claim 1 wherein said copolymer is introduced to said clay separately, followed by addition of a water reducing admixture.
13. The method of claim 1 wherein said copolymer is introduced to said clay together with a water reducing admixture.
14. The method of claim 13 wherein said water reducing admixture is an EO/PO polycarboxylate superplasticizer.
15. The method of claim 1 wherein said copolymer is introduced to said clay together with gluconate and/or an EO/PO polymer.