Aqueous dispersion of multi-stage polymeric particles and process of making the same

Patent metadata

Field	Value
Publication number	US-11384165-B2
Application number	US-201816972773-A
Country	US
Kind code	B2
Filing date	Jul 10, 2018
Priority date	Jul 10, 2018
Publication date	Jul 12, 2022
Grant date	Jul 12, 2022

Abstract

A stable aqueous dispersion of multi-stage polymeric particles comprising a polymer and an oligomer, and an aqueous freeze-thaw stable coating composition comprising the aqueous dispersion providing coatings made therefrom with acceptable scrub resistance.

First claim

What is claimed is:

1. An aqueous dispersion of multi-stage polymeric particles comprising a polymer and an oligomer,
wherein the polymer comprises,
(a1) structural units of a functional monomer mixture, comprising,
(i) 0.5% by weight or more of structural units of an α, β-ethylenically unsaturated carboxylic acid,
(ii) structural units of methyl acrylamide and/or sodium styrene sulfonate, and optionally
(iii) structural units of acrylamide;
wherein the total amount of (i), (ii), and (iii) is 2% by weight or more;
(a2) structural units of an alkyl ester of (meth)acrylic acid; and optionally,
(a3) structural units of a vinyl aromatic monomer;
wherein the oligomer has a weight average molecular weight of from 1,000 to 60,000 g/mol and comprises:
(b1) 0.1% by weight or more of structural units of an alkoxylated (meth)acrylate having the structure of formula (I),

wherein R 1 is H or CH 3 , R 2 is H or a C 1 -C 6 alkyl group, R 3 and R 4 are each independently H or CH 3 , m is an integer of from 8 to 50, and n is an integer of from 0 to 6; and optionally
(b2) structural units of a vinyl aromatic monomer;
wherein the structural units of the vinyl aromatic monomer in the multi-stage polymeric particles are present in a combined amount of 5% by weight or more; and
wherein the multi-stage polymeric particles comprise from 1% to 30% by weight of the oligomer; with percent by weight values relative to the weight of the multi-stage polymeric particles.

2. The aqueous dispersion of claim 1 , wherein the alkoxylated (meth)acrylate has the structure of formula (I), wherein n is 0 and m is an integer of from 15 to 35.

3. The aqueous dispersion of claim 1 , wherein the total amount of (i), (ii) and (iii) in the polymer is in the range of from 2.1% to 5%, by weight based on the weight of the multi-stage polymeric particles.

4. The aqueous dispersion of claim 1 , wherein the polymer comprises (i) from 0.5% to 5% of structural units of the α, β-ethylenically unsaturated carboxylic acid, and (ii) from 0.1% to 5% of structural units of methyl acrylamide and/or sodium styrene sulfonate.

5. The aqueous dispersion of claim 1 , wherein the polymer comprises from zero to 4% by weight of structural units of acrylamide.

6. The aqueous dispersion of claim 1 , wherein the polymer further comprises structural units of a phosphorous-containing acid monomer and/or salts thereof.

7. The aqueous dispersion of claim 1 , wherein the oligomer is present, based on the weight of the multi-stage polymeric particles, in an amount of from 3% to 15% by weight.

8. The aqueous dispersion of claim 1 , wherein the oligomer comprises, based on the weight of the multi-stage polymeric particles, from 0.3% to 5% by weight of structural units of the alkoxylated (meth)acrylate.

9. A process of preparing an aqueous dispersion of multi-stage polymeric particles by multi-stage free-radical polymerization, comprising at least one stage forming a polymer and at least one stage forming an oligomer in the presence of a chain transfer agent;
wherein the polymer comprises,
(a1) structural units of a functional monomer mixture, comprising,
(i) 0.5% by weight or more of structural units of an α, β-ethylenically unsaturated carboxylic acid,
(ii) structural units of methyl acrylamide and/or sodium styrene sulfonate, and optionally
(iii) structural units of acrylamide;
wherein the total amount of (i), (ii), and (iii) is 2% or more;
(a2) structural units of an alkyl ester of (meth)acrylic acid; and optionally,
(a3) structural units of a vinyl aromatic monomer; and
wherein the oligomer has a weight average molecular weight of from 1,000 to 60,000 g/mol and comprises:
(b1) 0.1% by weight or more of structural units of an alkoxylated (meth)acrylate having the structure of formula (I),

wherein R 1 is H or CH 3 , R 2 is H or a C 1 -C 6 alkyl group, R 3 and R 4 are each independently H or CH 3 , m is an integer of from 8 to 50, and n is an integer of from 0 to 6; and optionally
(b2) structural units of a vinyl aromatic monomer;
wherein the structural units of the vinyl aromatic monomer in the multi-stage polymeric particles are present in a combined amount of 5% by weight or more; and
wherein the multi-stage polymeric particles comprise from 1% to 30% by weight of the oligomer; with percent by weight values relative to the weight of the multi-stage polymeric particles.

10. An aqueous coating composition comprising the aqueous dispersion of multi-stage polymeric particles of claim 1 .

11. The aqueous coating composition of claim 10 , being substantially free of anti-freezing agents.

Assignees

• Dow Global Technologies Llc
• Rohm & Haas

Inventors

• Liu Han
• Liu Dan
• Zhang Qingwei
• Gong Zhi Juan
• Dong Xiangting
• Li Ling
• Lv Han

Classifications

• C09D131/02

  Homopolymers or copolymers of esters of monocarboxylic acids · CPC title

• C08F220/1804

  C4-(meth)acrylate, e.g. butyl (meth)acrylate, isobutyl (meth)acrylate or tert-butyl (meth)acrylate · CPC title

• C08F265/02

  on to polymers of acids, salts or anhydrides · CPC title

• C08F2/26 Primary

  anionic · CPC title

• C08F212/30

  Sulfur · CPC title