Production of dispersants by nitroxide-mediated solution polymerization

Patent metadata

Field	Value
Publication number	US-11028213-B2
Application number	US-201716461138-A
Country	US
Kind code	B2
Filing date	Nov 21, 2017
Priority date	Nov 22, 2016
Publication date	Jun 8, 2021
Grant date	Jun 8, 2021

Abstract

The present invention relates to processes for preparing a copolymer, especially a dispersant for solid particles, in particular a dispersant for mineral binder compositions, wherein ionizable monomers m1 and side chain-bearing monomers m2 are polymerized by nitroxide-mediated solution polymerization to give a copolymer, wherein the polymerization is conducted in the presence of an agent comprising a carboxyl group-bearing and phosphated alkoxy amine.

First claim

The invention claimed is:

1. A process for preparing a copolymer, comprising polymerizing ionizable monomers m1 and side chain-bearing monomers m2 by nitroxide-mediated solution polymerization to give the copolymer, wherein the polymerization is conducted in the presence of an agent comprising a carboxyl-bearing phosphated alkoxy amine; wherein
the nitroxide-mediated solution polymerization is conducted at a pH in the range of 7.5-13, and
the monomers are converted to a copolymer having block structure, wherein the side chain-bearing monomers m2 are present in at least one first block A and ionizable monomers m1 are present in at least one second block B any proportion of monomers m1 present in the first block A is less than 15 mol % based on all the monomers m2 in the first block A, and any proportion of monomers m2 present in the second block B is less than 15 mol % based on all the monomers m1 in the second block B.

2. The process as claimed in claim 1 , wherein
the proportion of monomers m1 present in the first block A is less than 5 mol % based on all the monomers m2 in the first block A, and
the proportion of monomers m2 present in the second block B is less than 5 mol % based on all the monomers m1 in the second block B.

3. The process as claimed in claim 1 , wherein
the proportion of monomers m1 present in the first block A is less than 1 mol % based on all the monomers m2 in the first block A, and
the proportion of monomers m2 present in the second block B is less than 1 mol % based on all the monomers m1 in the second block B.

4. The process as claimed in claim 1 , wherein a molar ratio of the ionizable monomers m1 used to the side chain-bearing monomers m2 used is in the range of 0.5-6.

5. The process as claimed in claim 1 , wherein the solution polymerization is effected in a polar solvent.

6. The process as claimed in at claim 1 , wherein the nitroxide-mediated solution polymerization is conducted at a temperature of 40-120° C.

7. The process as claimed in claim 1 , wherein the nitroxide-mediated solution polymerization is effected in the presence of a base.

8. The process as claimed in claim 1 , wherein the nitroxide-mediated solution polymerization is conducted at a pH in the range of 7.5-10.

9. The process as claimed in claim 1 , wherein the nitroxide-mediated solution polymerization is conducted at a pH in the range of 7.5-8.5.

10. The process as claimed in claim 1 , wherein the agent has exactly one carboxyl group and exactly one nitroxide group.

11. The process as claimed in claim 1 , wherein the agent is a compound of the formula X:

where
R 11 is a linear or branched alkyl radical having 1-6 carbon atoms;
R 12 and R 13 are each independently hydrogen or a linear or branched alkyl radical having 1-6 carbon atoms;
R 14 and R 15 are each independently a linear or branched alkyl radical having 1-6 carbon atoms;
R 16 and R 17 are each independently a linear or branched alkyl radical having 1-6 carbon atoms;
T independently 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.

12. The process as claimed in claim 1 , wherein the ionizable monomers m1 have a structure of the formula I:

and the side chain-bearing monomers m2 have a structure of the formula II:

where
R 1 , in each case independently, is —COOM, —SO 2 —OM,

—O—PO(OM) 2 and/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, or where R 1 forms 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—,
R 8 is a group of the formula -[AO] n —R a
where
A=C 2 - to C 4 -alkylene,
R a is H, a C 1 - to C 20 -alkyl group, -cycloalkyl group or -alkylaryl group, and

n=2-250.

13. The process as claimed in claim 12 , 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 where X in at least 75 mol %, of all monomers m2 is —O—.

14. The process as claimed in claim 1 , wherein at least one further monomer ms is present and is polymerized during the polymerization, wherein ms is optionally a monomer of the formula III:

where
R 5′ and R 6′ , in each case independently, are H or an alkyl group having 1 to 5 carbon atoms,
R 7′ is H, —COOM or an alkyl group having 1 to 5 carbon atoms,
m′=0, 1 or 2,
p′=0 or 1;
Y, in each case independently, is a chemical bond or —O—;
Z, in each case independently, is a chemical bond, —O— or —NH—; and
R 9 , in each case independently, is an alkyl group, cycloalkyl group, alkylaryl group, aryl group, hydroxyalkyl group or acetoxyalkyl group, each having 1-20 carbon atoms.

Assignees

• Sika Tech Ag

Inventors

• Weidmann Jürg
• Ulber Fabia
• Zimmermann Jörg

Classifications

• C08F290/062 Primary

  Polyethers · CPC title

• C04B28/00

  Compositions of mortars, concrete or artificial stone, containing inorganic binders or the reaction product of an inorganic and an organic binder, e.g. polycarboxylate cements · CPC title

• C04B24/2658

  containing polyether side chains · CPC title

• C08F2438/02

  Stable Free Radical Polymerisation [SFRP]; Nitroxide Mediated Polymerisation [NMP] for, e.g. using 2,2,6,6-tetramethylpiperidine-1-oxyl [TEMPO] · CPC title

• C04B2103/408

  Dispersants · CPC title