SYNTHESIS AND USE OF GYPSUM SEEDING MATERIAL

摘要

Producing calcium sulfate dihydrate, comprises reacting a water-soluble calcium compound with a water-soluble sulfate compound in the presence of water and an acid group-containing polymer. The acid group-containing polymer comprises polyether groups (I). Producing calcium sulfate dihydrate, comprises reacting a water-soluble calcium compound with a water-soluble sulfate compound in the presence of water and an acid group-containing polymer. The acid group-containing polymer comprises polyether groups of formula (Q-U1-(C(O)) k-X-(AlkO) n-W1) (I).. Q : binding site to acid group-containing polymer; U1 : chemical bond or 1-8C alkylene; X : O or NR1; k : 0 or 1; n : 3-300, based on acid group-containing polymer; Alk : 2-4C alkylene; W1 : H, 1-6C alkyl, aryl group or Y1F1; Y1 : optionally branched 2-8C alkylene, which comprises phenyl ring; F1 : 5- to 10-membered nitrogen heterocycle, which is connected through N, and comprises C and 1-3 O, N or S as ring elements, where nitrogen ring element comprises R2, and at least two carbon ring elements are present as carbonyl; and R1, R2 : H, 1 -4C alkyl or benzyl. Independent claims are also included for: (1) the calcium sulfate dihydrate, which is produced by the above mentioned method; and (2) using the calcium sulfate dihydrate for producing a gypsum board.