ADDITIVE COMPOSITION OF GYPSUM PLASTER AND METHOD FOR PREPARING THE SAME

摘要

An additive composition of a gypsum plaster is provided to improve workability of a gypsum plaster and to reduce lumps of the gypsum plaster. An additive composition of a gypsum plaster includes a surfactant and at least one cellulose ether selected from methyl cellulose having a degree of substitution by the methyl group of 0.27-2.0, hydroxypropylmethyl cellulose having a degree of substitution by the methyl group of 0.27-2.50 and the molar substitution of the hydroxypropyl group ranging from 0.02 to 1.1, hydroxyethylmethyl cellulose having the degree of substitution by the methyl group of 0.27-2.40 and the molar substitution of the hydroxyethyl group ranging from 0.03 to 1.3, and hydroxyethylcellulose having the molar substitution of the hydroxyethyl group ranging from 0.3 to 5.0. Further, a viscosity of the cellulose ether is 10 to 200000 cps, and the surfactant is an anionic surfactant, a nonionic surfactant or a mixture thereof.