Copolymers having a gradient structure

• US 10,550,037 B2
• Filed: 09/22/2016
• Issued: 02/04/2020
• Est. Priority Date: 09/24/2015
• Status: Active Grant

• Current Assignee: Sika Technology Ag (Compagnie de Saint-Gobain SA)
• Original Assignee: Sika Technology Ag (Compagnie de Saint-Gobain SA)
• Inventors: Weidmann, Jurg, Zimmermann, Jorg
• Primary Examiner(s): Jones, Robert S
• Application Number:
  US15/762,651
• Publication Number:
  US 20180265407A1
• Time in Patent Office: 1,230 Days
• CPC Class Codes: C04B 2103/0063 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 Class Codes: C04B 2103/408 Dispersants
• CPC Class Codes: C04B 24/165 containing polyether side chains
• CPC Class Codes: C04B 24/246 containing polyether side chains
• CPC Class Codes: C04B 24/2605 containing polyether side chains
• CPC Class Codes: C04B 24/2647 containing polyether side chains
• CPC Class Codes: C04B 24/2658 containing polyether side chains
• CPC Class Codes: C04B 24/267 containing polyether side chains
• CPC Class Codes: C04B 24/2694 containing polyether side chains

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.

Claims

1. A process for preparing a copolymer, the process comprising:

polymerizing together ionizable monomers m1 and side chain-bearing monomers m2 to form a gradient structure in the copolymer, wherein the polymerization includes;

converting or polymerizing a portion of the side chain-bearing monomers m2 to form at least one side chain-bearing monomer unit M2 essentially in the absence of the ionizable monomers m1 until a predetermined conversion is attained, the predetermined conversion being in a range of from 1 to 74 mol % of the side chain-bearing monomers m2 being converted or polymerized, and then

polymerizing together unconverted side chain-bearing monomers m2 with the ionizable monomers m1, wherein;

the copolymer has a polymer backbone and side chains bonded thereto,

the copolymer comprises at least one ionizable monomer unit M1 and the at least one side chain-bearing monomer unit M2, and

the copolymer has the 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.

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

1.5.

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

4. The process as claimed in claim 1, wherein the copolymer, in addition to the at least one section A, has a further section B having an essentially constant local concentration of monomers and/or a random distribution of monomers, and the further section B comprises the ionizable monomer units M1 and/or the side chain-bearing monomer units M2.

5. The process as claimed in claim 4, wherein the further section B, based on all monomer units present therein, comprises at least 30 mol % of the side chain-bearing monomer units M2, and a proportion of the ionizable monomer units M1 present in the further section B is less than 25 mol %, based on all the monomer units M2 in the further section B.

6. The process as claimed in claim 1, wherein the ionizable monomer unit M1 has a structure represented by formula I

7. The process as claimed in claim 1, wherein R¹=COOM;

R² and R⁵, independently of one another, are H, —

CH₃, or mixtures thereof;

R³ and R⁶, independently of one another, are H or —

CH₃;

R⁴ and R⁷, independently of one another, are H or —

COOM; and

X in at least 75 mol % of all the monomer units M2 is —

O—

.

8. The process as claimed in claim 1, wherein the polymerization of the ionizable monomers m1 and the side chain-bearing monomers m2 to form the gradient structure in the copolymer is effected by a controlled free-radical polymerization and/or a living free-radical polymerization.

9. The process as claimed in claim 1, wherein the ionizable monomers m1 have a structure represented by formula IV: