Copolymers having a gradient structure

Patent metadata

Field	Value
Publication number	US-11066330-B2
Application number	US-201916711570-A
Country	US
Kind code	B2
Filing date	Dec 12, 2019
Priority date	Sep 24, 2015
Publication date	Jul 20, 2021
Grant date	Jul 20, 2021

Abstract

The present invention relates to a copolymer, especially for use as a dispersant for solid particles, in particular for use as dispersant for mineral binder compositions, having a polymer backbone and side chains bonded thereto, comprising at least one ionizable monomer unit M1 and at least one side chain-bearing monomer unit M2, wherein the copolymer has a gradient structure in at least one section A in a direction along the polymer backbone with regard to the ionizable monomer unit M1 and/or with regard to the side chain-bearing monomer unit M2.

First claim

The invention claimed is:

1. A copolymer having a polymer backbone and side chains bonded thereto, and comprising at least one ionizable monomer unit M1 and at least one side chain-bearing monomer unit M2, the copolymer having:
at least one section A having a gradient structure in a direction along the polymer backbone with regard to the ionizable monomer unit M1 and/or with regard to the side chain-bearing monomer unit M2, and
at least one section B having an essentially constant local concentration of monomers and/or a random distribution of monomers, wherein the at least one section B comprises ionizable monomer units M1 and/or side chain-bearing monomer units M2,
wherein a ratio of the number of monomer units in the at least one section A to the number of monomer units in the at least one section B is in the range of 80:20 to 20:80.

2. The copolymer as claimed in claim 1 , wherein the polydispersity of the copolymer is <1.5.

3. The copolymer as claimed in claim 1 , wherein the polydispersity of the copolymer is in the range of 1.0-1.4.

4. The copolymer as claimed in claim 1 , wherein the at least one section A has a proportion of at least 30% of monomer units, based on a total number of the monomer units in the polymer backbone.

5. The copolymer as claimed in claim 1 , wherein the at least one section A has a proportion of at least 50% of monomer units, based on a total number of the monomer units in the polymer backbone.

6. The copolymer as claimed in claim 1 , wherein the ratio of the number of monomer units in the at least one section A to the number of monomer units in the at least one section B is in the range of 70:30 to 30:70.

7. The copolymer as claimed in claim 1 , wherein the at least one section B, based on all the monomer units present therein, comprises at least 30 mol % of side chain-bearing monomer units M2, and any proportion of ionizable monomer units M1 present in the at least one section B is less than 25 mol % based on all the monomer units M2 in the at least one section B.

8. The copolymer as claimed in claim 1 , wherein the at least one section B comprises a total of 5-70 monomer units.

9. The copolymer as claimed in claim 1 , wherein the at least one section B comprises a total of 7-40 monomer units.

10. The copolymer as claimed in claim 1 , wherein the at least one section A comprises 5-70 monomer units M1 and 5-70 monomer units M2.

11. The copolymer as claimed in claim 1 , wherein the at least one section A comprises 7-40 monomer units M1 and 7-40 monomer units M2.

12. The copolymer as claimed in claim 1 , wherein the at least one section A, based on the weight-average molecular weight of the overall copolymer, has a proportion by weight of at least 30%.

13. The copolymer as claimed in claim 1 , wherein the at least one section A directly adjoins the at least one section B.

14. The copolymer as claimed in claim 1 , wherein the ionizable monomer unit M1 has a structure of the following formula (I)

and the side chain-bearing monomer unit M2 includes a structure of the following formula (II)

where:
R 1 , in each case independently, is —COOM, —SO 2 —OM, —O—PO(OM) 2 , or —PO(OM) 2 ,
R 2 , R 3 , R 5 and R 6 , in each case independently, are —H or an alkyl group having 1 to 5 carbon atoms,
R 4 and R 7 , in each case independently, are —H, —COOM, or an alkyl group having 1 to 5 carbon atoms,
R 1 may optionally form a ring together with R 4 to give —CO—O—CO—,
M, independently of one another, represents H + , an alkali metal ion, an alkaline earth metal ion, a di- or trivalent metal ion, an ammonium ion, or an organic ammonium group;
m=0, 1, or 2,
p=0 or 1,
X, in each case independently, is —O— or —NH—, and
R 8 is a group of the formula -[AO] n —R a , where
A=C 2 - to C 4 -alkylene,
R 3 is —H, a C 1 - to C 20 -alkyl group, a -cycloalkyl group, or an -alkylaryl group, and
n=2-250.

15. The copolymer as claimed in claim 14 , wherein n=10-200.

16. The copolymer as claimed in claim 14 , wherein:
R 1 =—COOM;
R 2 and R 5 , independently of one another, are —H, —CH 3 , or mixtures thereof;
R 3 and R 6 , independently of one another, are —H or —CH 3 ;
R 4 and R 7 independently of one another, are —H or —COOM; and
X in at least 75 mol % of all monomer units M2 is —O—.

17. The copolymer as claimed in claim 13 , wherein:
R 1 =—COOM;
R 2 and R 5 are —CH 3 ;
R 3 and R 6 are —H;
R 4 and R 7 are —H;
X in at least 99 mol % of all monomer units M2 is —O—; and
m=0, p=1, and n=19-45.

18. The copolymer as claimed in claim 1 , wherein a weight-average molecular weight M W of the overall copolymer is in the range of 12,000-80,000 g/mol.

19. The copolymer as claimed in claim 1 , wherein a weight-average molecular weight M W of the overall copolymer is in the range of 12,000-50,000 g/mol.

20. A method for dispersing solid particles, comprising mixing the copolymer as claimed in claim 1 with solid particles.

21. A mineral binder composition comprising at least one copolymer as claimed in claim 1 .

22. A shaped body obtained by curing a mineral binder composition as claimed in claim 21 after addition of water.

Assignees

• Sika Tech Ag

Inventors

• Weidmann Jürg
• Zimmermann Jörg

Classifications

• C04B24/246

  containing polyether side chains · CPC title

• C04B2103/0063

  obtained by an unusual polymerisation process, e.g. by changing the molar ratio of the different monomers during the polymerisation process (C04B2103/0058 - C04B2103/0061 take precedence) · CPC title

• C04B24/165

  containing polyether side chains · CPC title

• C04B24/2658

  containing polyether side chains · CPC title

• C04B24/2694

  containing polyether side chains · CPC title