ADDITIVE FOR CEMENT

Japanese Patent JP3817803

B2

PROBLEM TO BE SOLVED: To obtain an additive capable of shortening the dehydration time in a draining step of a dehydrating press when producing a slate and improving the productivity by adding ethylene oxide and propylene oxide or butylene oxide at a specific molar ratio to a mixture of a natural oil and fat and a limited polyhydric alcohol and carrying out the addition reaction. SOLUTION: This additive for a cement comprises a reactional product prepared by carrying out an addition reaction of a mixture of a natural oil and fat such as coconut oil, palm oil, lard, beef tallow, a fish oil, etc., with a polyhydric alcohol of the formula {R1 is a 1-22C hydrocarbon group or acyl group; Z is a residue of a compound having 1-8 hydroxyl groups; 0≤(p)≤7; 1≤(q)≤8; 1≤[(p)+(q)]≤8}, e.g. glycerol or ethylene glycol with (A) ethylene oxide or (B) propylene oxide or butylene oxide is then carried out. The molar ratio of the components A to B is (1:40) to (1:2). The reactional product is capable of improving the separation of an aggregate from water when producing a slate.