Anionic water-soluble additives

1. Anionically modified copolymers obtained by polymerization of monomers (A), (B) and (C) to yield nonionic copolymers having reactive terminal OH groups, and subsequent conversion of the terminal OH groups to anionic end groups, wherein

(A) is a monomer of formula (I)

wherein

A is C 2 -C 4 -alkylene,

B is a C 2 -C 4 -alkylene other than A,

R is hydrogen or methyl,

m is from 1 to 500;

n is from 1 to 500,

and the sum total of m+n is from 2 to 1000;

(B) is an ethylenically unsaturated monomer containing an aromatic group; and

(C) is an ethylenically unsaturated monomer containing an alkyl radical, and wherein the copolymer is of the formulae (IV) or (V)

wherein

A is C 2 -C 4 -alkylene,

B is a C 2 -C 4 -alkylene other than A,

R is hydrogen or methyl,

m is from 1 to 500;

n is from 1 to 500;

and the sum total of m+n is from 2 to 1000;

X a is an aromatic or araliphatic radical having 3 to 30 carbon atoms optionally containing one or more of the hetero atoms N, O and S,

Z a is H or (C 1 -C 4 )-alkyl,

Z b is H or (C 1 -C 4 )-alkyl,

Z c is H or (C 1 -C 4 )-alkyl;

R 2 is hydrogen or methyl,

Y is an aliphatic hydrocarbyl radical having 1 to 30 carbon atoms, optionally linear, branched or cyclic, and optionally contain hetero atoms O, N S or a combination thereof and optionally are unsaturated,

W b is oxygen or an NH group;

R 1 is hydrogen or methyl,

X b is an aromatic or araliphatic radical having 3 to 30 carbon atoms optionally containing one or more of the hetero atoms N, O and S,

W a is oxygen or an NH group,

a=0.01 to 0.8; b=0.001 to 0.8; c=0.001 to 0.8;

subject to the proviso that the sum total of a+b+c is equal to 1,

Q is SO 3 , CH 2 COO, PO 3 M or sulfosuccinate, where M represents H, a monovalent metal cation, a divalent metal cation, NH 4 + , a secondary, tertiary or quaternary ammonium ion or a combination thereof.

2. The copolymer as claimed in claim 1 , wherein the molar fraction of monomer (A) is 1 to 80%, monomer (B) is 0.1 to 80% and monomer (C) is 0.1 to 80%.

3. The copolymer as claimed in claim 1 , wherein the molar fraction of monomer (A) is 10 to 70%, monomer (B) is 10 to 60% and monomer (C) is 10 to 60%.

4. The copolymer as claimed in claim 1 , wherein the alkylene oxide units (A-O) m and (B-O) n are in blocks.

5. The copolymer as claimed in claim 1 , wherein (A-O) m are propylene oxide units and (B-O) n are ethylene oxide units, or (A-O) m are ethylene oxide units and (B-O) n are propylene oxide units, and the molar fraction of ethylene oxide units is 50 to 98%, based on the sum total of ethylene oxide and propylene oxide units.

6. The copolymer as claimed in claim 5 , wherein the molar fraction of ethylene oxide units is 60 to 95%, based on the sum total of ethylene oxide and propylene oxide units.

7. The copolymer as claimed in claim 1 , wherein the anionic end groups are one of SO 3 M, CH 2 COOM, PO 3 M 2 and sulfosuccinate, where M represents H, a monovalent metal cation, a divalent metal cation, NH 4 + , a secondary, tertiary or quaternary ammonium ion or a combination thereof.

8. A process for producing a copolymer as claimed in claim 1 , comprising the step of free-radically polymerizing the monomers (A), (B) and (C) and converting the resulting terminal OH groups to anionic end groups.

9. A dispersant comprising a copolymer as claimed in claim 1 .

10. The copolymer as claimed in claim 1 , wherein Y is an aliphatic hydrocarbyl radical having 6 to 30 carbon atoms.

11. The copolymer as claimed in claim 1 , wherein Y is an aliphatic hydrocarbyl radical having 9 to 20 carbon atoms.

12. A pigment or filler dispersant comprising a copolymer as claimed in claim 1 .