| 主权项 |
1. A method for making a setting accelerator suitable for binders based on calcium sulfate, the method comprising subjecting materials consisting of gypsum together with at least one polycarboxylate to a dry grinding,
wherein the polycarboxylate is used in a fraction of 0.05 to 2 wt. % with respect to the gypsum, wherein the polycarboxylate comprises: a) a molar parts of a structural unit S1 of formula (I): b) b molar parts of a structural unit S2 of formula (II): c) c molar parts of a structural unit S3 of formula (III): d) d molar parts of a structural unit S4 of formula (IV): where M independently of each other represents H+, an alkaline metal ion, alkaline earth metal ion, a divalent or trivalent metal ion, an ammonium ion or an organic ammonium group, each Ru independently of the others stands for hydrogen or a methyl group, each Rv independently of the others stands for hydrogen or COOM, m=0, 1 or 2, p=0 or 1, R1 and R2 independently of each other stand for a C1 to C20 alkyl group, cyclo-alkyl alkylaryl group [AO]n—R4, where A=C2 to C4 alkylene, R4 stands for H, a C1 to C20 alkyl group, cyclohexyl group or alkylaryl group, and n=2−250, R3 independently of each other stand for NH2, —NR5R6, —OR7NR8R9,
where R5 and R6 independently of each other stand for a C1 to C20 alkyl group, cycloalkyl group, alkylaryl group or aryl group, or for a hydroxyalkyl group or for an acetoxyethyl (CH3—CO—O—CH2—CH2—) or for a hydroxy-isopropyl (HO—CH(CH3)—CH2—) or for an acetoxyisopropyl group (CH3—CO—O—CH(CH3)—CH2—); or R5 and R6 together form a ring of which nitrogen is a part, in order to make up a morpholine or imidazoline ring; R7 is a C2 -C4 alkylene group, R8 and R9 independently of each other represent a C1 to C20 alkyl group, cycloalkyl group, alkylary group, aryl group or a hydroxyalkyl group, and where a, b, c and d represent molar fractions of the respective structural units S1, S2, S3 and S4, wherein a=0.1−0.9, b=0.1−0.9, c=0−0.8, d=0−0.8,and provided that a+b+c+d=1. |
