| 摘要 |
PROBLEM TO BE SOLVED: To provide a dispersant for calcium carbonate, which has a high effect to stably disperse calcium carbonate with excellent handlability, and is especially suitable as a dispersant for wet milling treatment for heavy calcium carbonate. SOLUTION: The dispersant for calcium carbonate comprises (meth)acrylic acid based copolymer having structural units: (a) a unit originated from (meth)acrylic acid (salt) which is prepared by copolymerizing (meth)acrylic ester of formula, CH<SB>2</SB>=C(R<SP>1</SP>)-COO-(CH<SB>2</SB>)<SB>m</SB>-(R<SP>2</SP>-O)<SB>n</SB>-R<SP>3</SP>(in formula, R<SP>1</SP>is H or Mt; R<SP>2</SP>is a propylene group; R<SP>3</SP>is H or a monovalent 1-6C hydrocarbon group; m is 0-4 and n is 2-10), with (meth)acrylic acid (salt); and (b) a unit originated from the above (meth)acrylic acid ester; wherein the relationship of A/B=3-15, where A= mole% of unit (a) in (meth)acrylic acid based copolymer; and B=[mole% of unit (b)in (meth)acrylic acid based copolymer]×[addition mole number n of propylene oxide unit in unit (b)], is satisfied and the number average molecular weight (Mn) of the (meth)acrylic acid based copolymer is 2,000-4,000. COPYRIGHT: (C)2009,JPO&INPIT
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