Non-ionic additives soluble in water and in solvents

1. A copolymer obtained by polymerization of monomers (A), (B), (C) and (D), 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 a monomer of formula (II)

wherein

D is C 3 -alkylene,

R is hydrogen or methyl,

o is from 2 to 500;

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

(D) is an ethylenically unsaturated monomer containing an alkyl radical, wherein the monomer (C) is a compound of formula (IIIa) or (IIIb)

wherein

X a is an aromatic or araliphatic radical having 3 to 30 carbon atoms, optionally containing heteroatoms selected from the group consisting of N, O and S,

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

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

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

wherein

R 1 is hydrogen or methyl,

X b is an aromatic or araliphatic radical having 3 to 30 carbon atoms optionally containing heteroatoms from the group consisting of N, O and S,

W a is oxygen or an NH group and wherein the monomer (D) is a compound of formula (IV):

wherein

R 2 is hydrogen or methyl,

Y is an aliphatic hydrocarbyl radical having 1 to 30 carbon atoms, optionally linear or branched or cyclic, and optionally contains heteroatoms selected from the group consisting of O, N and S and is optionally unsaturated, and

W b is oxygen or an NH group.

2. The copolymer as claimed in claim 1 , wherein the molar fraction of monomer (A) is 0.1 to 90%, of monomer (B) is 0.1 to 90%, of monomer (C) is 0.1 to 90% and of monomer (D) is 0.1 to 90%, the molar fractions summing to 100%.

3. The copolymer as claimed in claim 1 , wherein the molar fraction of monomer (A) is 0.1 to 70%, of monomer (B) is 10 to 80%, of monomer (C) is 0.1 to 50% and of monomer (D) is 0.1 to 50%, the molar fractions summing to 100%.

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 in monomer (A) (A-O) m are propylene oxide units and (B-O) n represents ethylene oxide units, or (A-O) m are ethylene oxide units and (B-O) n are propylene oxide units.

6. The copolymer as claimed in claim 5 , wherein the molar fraction of ethylene oxide units in monomer (A) is 50 to 98%, based on the sum total of ethylene oxide and propylene oxide units.

7. The copolymer as claimed in claim 1 , wherein the monomer (C) is styrene, 1-vinylimidazole, benzyl methacrylate, 2-phenoxyethyl methacrylate or phenethyl methacrylate.

8. The copolymer as claimed in claim 1 , wherein the monomer (D) is an alkyl ester or alkylamide of acrylic acid or methacrylic acid, wherein the alkyl is methyl, ethyl, propyl, butyl, isobutyl, 2-ethoxyethyl, myristyl, octadecyl, 2-ethylhexyl or lauryl.

9. A process for producing the copolymer as claimed in claim 1 , comprising the steps of free-radically polymerizing the monomers (A), (B), (C) and (D).

10. A dispersant, wherein the dispersant comprises the copolymer as claimed in claim 1 .

11. The dispersant as claimed in claim 10 , wherein the dispersant is a pigment or filler dispersant.