Polymers and use thereof as dispersants having a foam-inhibiting effect
View Patent ↗The invention relates to polymers that can be obtained by polymerizing the monomers (A), (B), and (D), and optionally (C), where (A) is a monomer of formula (I), wherein A stands for C 2 to C 4 alkylene, B stands for a C 2 to C 4 alkylene different from A, R stands for hydrogen or methyl, m stands for a number from 1 to 500, n stands for a number from 1 to 500, (B) is an ethylenically unsaturated monomer that contains at least one carboxylic acid function, (C) is optionally a further ethylenically unsaturated monomer different from (A) and (B), (D) is a monomer of formula (II), wherein D stands for C 2 to C 4 alkylene, E stands for a C 2 to C 4 alkylene group different from D, F stands for a C 2 to C 4 alkylene group different from E, R stands for hydrogen or methyl, o stands for a number from 1 to 500, p stands for a number from 1 to 500, q stands for a number from 1 to 500, and wherein the weight fraction of the monomers is 35 to 99% for the macromonomer (A), 0.5 to 45% for the monomer (B), 0 to 20% for the monomer (C), and 1 to 20% for the monomer (D), and to the use of said polymers as defoamers for inorganic solid suspensions.
1. A polymer containing structural units derived from monomers (A), (B) and (D), wherein
(A) is a monomer of formula (I)
where
A is C 2 - to C 4 -alkylene,
B is a C 2 - to C 4 -alkylene other than A,
R is hydrogen or methyl,
m is a number from 1 to 500,
n is a number from 1 to 500,
(B) is an ethylenically unsaturated monomer which contains at least one carboxylic acid function,
(D) is a monomer of formula (II)
where
D is C 2 - to C 4 -alkylene,
E is a C 2 - to C 4 -alkylene group other than D,
F is a C 2 - to C 4 -alkylene group other than E,
R is hydrogen or methyl,
is a number from 1 to 500,
P is a number from 1 to 500,
q is a number from 1 to 500
and wherein the weight fraction of monomers is 35 to 98.5% in respect of monomer (A), 0.5 to 45% in respect of monomer (B), and 1 to 20% in respect of monomer (D).
2. The polymer as claimed in claim 1 , wherein (A-O) m is a propylene oxide unit and (B-O) n is an ethylene oxide unit, or (A-O) m is an ethylene oxide unit and (B-O) n is a propylene oxide unit, and the molar fraction of ethylene oxide units is from 50 to 99 wt % based on the sum total (100%) of all ethylene oxide and propylene oxide units (A-O) m and (B-O) n .
3. The polymer as claimed in claim 1 , wherein m is a number from 1 to 150.
4. The polymer as claimed in claim 1 , wherein n is a number from 3 to 300.
5. The polymer as claimed in claim 1 , wherein n+m is between 2 and 500.
6. The polymer as claimed in claim 1 , monomer (B) is selected from the group consisting of monoethylenically unsaturated mono- and dicarboxylic acids having 3 to 8 carbon atoms.
7. The polymer as claimed in claim 1 , further comprising (C) an ethylenically unsaturated monomer other than (A) and (B), wherein monomer (C) is selected from the group consisting of monoethylenically unsaturated sulfonic acids, phosphonic acids and/or their salts, and monoallyl polyalkylene glycols.
8. The polymer as claimed in claim 7 , wherein monomer (C) is in an amount of at least 0.5 wt % and monomer (A) is in an amount of at most 98 wt %.
9. The polymer as claimed in claim 1 , wherein the alkylene oxide units (D-O) o , (E-O) p and (F-O) q are in a block type arrangement and (D-O) o is a propylene oxide unit, (E-O) p is a ethylene oxide unit and (F-O) q is a propylene oxide unit, and wherein the molar fraction of ethylene oxide units is 10 to 90% based on the sum total (100%) of ethylene oxide and propylene oxide units (D-O) o , (E-O) p and (F-O) q .
10. The polymer as claimed in claim 1 , wherein o is a number from 1 to 100.
11. The polymer as claimed in claim 1 , wherein p is a number from 1 to 100.
12. The polymer as claimed in claim 1 , wherein q is a number from 1 to 100.
13. The polymer as claimed in claim 1 , wherein the sum o+p+q is between 3 and 500.
14. The polymer as claimed in claim 1 having a molecular weight of 10 3 g/mol to 10 9 g/mol.
15. A defoamer or dispersant for inorganic solid suspensions comprising the polymer as claimed in claim 1 , in an amount of 0.01 to 15 wt %, based on the weight of the inorganic solid suspension.
16. A process for defoaming and dispersing inorganic solid suspensions comprising the step of adding to an inorganic solid suspension at least one polymer as claimed in claim 1 , in an amount of 0.01 to 15 wt %, based on the weight of the inorganic solid suspension.
17. The polymer as claimed in claim 1 having a molecular weight of 10 3 g/mol to 10 6 g/mol.
18. The polymer as claimed in claim 1 having a molecular weight of 10 5 g/mol.