Aqueous cement composition
View Patent ↗A fresh aqueous cement composition suitable for building purposes is described. It contains, besides a hydraulic cement, a methyl ethyl cellulose ether having a DS methyl of 0.4-2.2, a DS ethyl of 0.05-0.8 and a MS hydroxy-(C 2 -C 3 )-alkyl of 0-2. The celulose ether imparts excellent rheology properties, including a high water-retention combined with a long open time, to the cement composition. A dry blend and a rheology additive containing the cellulose ether are also described.
1. A fresh aqueous cement composition comprising a hydraulic cement and a cellulose ether, wherein the composition comprises a methyl ethyl cellulose ether having a DS methyl of 0.4-2.2, a DS ethyl of 0.05-0.8 and a MS hydroxy-(C 2 -C 3 )-alkyl of 0-2.
2. The cement composition of claim 1 wherein the methyl ethyl cellulose ether has a DS methyl of 0.6-1.8, a DS ethyl of 0.1-0.5 and a MS hydroxy-(C 2 -C 3 )-alkyl of 0.1-1.2.
3. The cement composition of claim 2 wherein the hydroxyalkyl group is hydroxyethyl.
4. The cement composition of claim 2 wherein the hydroxyalkyl is hydroxypropyl.
5. The cement composition of claim 1 wherein the composition contains about 0.05% to about 3% by dry weight of the methyl ethyl cellulose ether.
6. The cement composition of claim 1 wherein the composition comprises about 0.05% to about 3% by dry weight of the methyl ethyl cellulose ether; about 8% to about 99.5% by dry weight of the composition of the hydraulic cement; 0 to about 91% by dry weight of the composition of a filler having a particle size of 5 mm or less; and about 10% to about 60% by weight of the composition of water.
7. The cement composition of claim 6 further comprising about 0 to about 10% by dry weight of the composition of an ingredient selected from the group consisting of air-entraining agents, retarders, accelerator, nonpolymeric plasticizers, pigments, colorants, corrosion inhibitors, and mixtures thereof.
8. The cement composition of claim 6 comprising about 0.1% to about 2% by dry weight of the methyl ethyl cellulose ether; about 12% to about 65% by dry weight of the composition of the hydraulic cement, about 45% to about 83% by dry weight of the composition of the filler; and about 15% to about 40% by weight of the composition of water.
9. The cement composition of claim 8 further comprising about 0.05% to about 10% by dry weight of the composition of an ingredient selected from the group consisting of air-entraining agents, retarders, accelerator, nonpolymeric plasticizers, pigments, colorants, corrosion inhibitors, and mixtures thereof.
10. A dry blend for use in the preparation of a fresh cement composition, wherein the dry blend comprises
(i) about 0.05% to about 3% by dry weight of a methyl ethyl cellulose ether having a DS methyl of 0.4-2.2, a DS ethyl of 0.05-0.8 and a MS hydroxy-(C 2 -C 3 )-alkyl of 0-2;
(ii) about 8% to about 99.5% by dry weight of the composition of a hydraulic cement; and
(iii) 0 to about 91% by dry weight of the composition of a filler having a particle size of 5 mm or less.
11. The dry blend of claim 10 further comprising 0 to about 10% by dry weight of the composition of an ingredient selected from the group consisting of air-entraining agents, retarders, accelerator, nonpolymeric plasticizers, pigments, colorants, corrosion inhibitors, and mixtures thereof.
12. The dry blend of claim 10 comprising about 0.1 to about 2% by dry weight of the methyl ethyl cellulose ether; about 12 to about 65% by dry weight of the composition of the hydraulic cement; about 45 to about 83% by dry weight of the composition of the filler; and about 0.05 to about 4% by dry weight of the composition of an ingredient selected from the group consisting of air-entraining agents, retarders, accelerators, nonpolymeric plasticizers, pigments, colorants, corrosion inhibitors and mixtures thereof.
13. A rheology additive for use in a fresh cement composition or dry blend, said rheology additive comprising:
(i) about 40 to about 98.5% by dry weight of a methyl ethyl cellulose ether having a DS methyl of 0.4-2.2, a DS ethyl of 0.05-0.8 and a MS hydroxy-(C 2 -C 3 )-alkyl of 0-2;
(ii) about 1.5 to about 60% by weight of a water-soluble or water-dispersible synthetic organic polymer resistant to alkali; and
(iv) 0 to about 50% by weight of clay.
14. The cement composition of claim 1 which additionally comprises
(i) about 1.5 to about 60% by weight of a water-soluble or water-dispersible synthetic organic polymer resistant to alkali; and
(iv) 0 to about 50% by weight of clay.