Aqueous coating composition and method of preparing the same

Patent metadata

Field	Value
Publication number	US-10745583-B2
Application number	US-201616094917-A
Country	US
Kind code	B2
Filing date	May 13, 2016
Priority date	May 13, 2016
Publication date	Aug 18, 2020
Grant date	Aug 18, 2020

Abstract

An aqueous coating composition providing the resulting coatings with balanced flexibility and anti-tacky properties, and a method of preparing the aqueous coating composition.

First claim

What is claimed is:

1. An aqueous coating composition comprising:
colloidal silica and a polyurethane-acrylic polymer,
wherein the colloidal silica is present in an amount of from 5% to 30% by solids weight, based on the total solids weight of the colloidal silica and the polyurethane-acrylic polymer, and has an average particle size less than 150 nm;
wherein the polyurethane-acrylic polymer is present in an amount of from 70% to 95% by solids weight, based on the total solids weight of the colloidal silica and the polyurethane-acrylic polymer, and is obtained by forming an acrylic polymer in an aqueous medium by an emulsion polymerization in the presence of a polyurethane;
wherein the acrylic polymer having a Tg of from −13° C. to 10° C. comprises as polymerized units, based on the weight of the acrylic polymer,
(i) from 0.5% to 4% by weight of an ethylenically difunctional or multifunctional compound, and
(ii) from 96% to 99.5% by weight of an ethylenically monofunctional compound; and
wherein the weight ratio of polyurethane to acrylic polymer in the polyurethane- acrylic polymer is from 30/70 to 99/1.

2. The aqueous coating composition of claim 1 , wherein the acrylic polymer has a Tg of from −10° C. to 0° C.

3. The aqueous coating composition of claim 1 , wherein the colloidal silica is present in an amount of from 7.5% to 20% by solids weight, based on the total solids weight of the colloidal silica and the polyurethane-acrylic polymer.

4. The aqueous coating composition of claim 1 , wherein the colloidal silica has an average particle size less than 100 nm.

5. The aqueous coating composition of claim 1 , wherein the ethylenically
difunctional or multifunctional compound is selected from allyl (meth)acrylate, hexanediol di(meth)arcylate, ethylene glycol di(meth)acrylate, neopentyl glycol di(meth)acrylate, butanediol di(meth)acrylate, trimethylolpropane tri(meth)acrylate, or mixtures thereof.

6. The aqueous coating composition of claim 1 , wherein the ethylenically monofunctional compound is selected from a (meth)acrylic acid alkyl ester, a vinyl aromatic compound, or mixtures thereof.

7. The aqueous coating composition of claim 6 , wherein the ethylenically monofunctional compound is selected from butyl (meth)acrylate, iso-butyl (meth)acrylate, 2-ethylhexyl acrylate, lauryl (meth)acrylate, stearyl (meth)acrylate, or mixtures thereof.

8. The aqueous coating composition of claim 1 , wherein the weight ratio of polyurethane to acrylic polymer in the polyurethane-acrylic polymer is from 35/65 to 60/40.

9. The aqueous coating composition of claim 1 , wherein the combined content of the colloidal and the polyurethane-acrylic polymer is from 80% to 100% by solids weight, based on the total solids weight of the coating composition.

10. The aqueous coating composition of claim 1 , wherein the polyurethane has a Tg of from −60° C. to 0° C.

11. The aqueous coating composition of claim 1 , wherein the polyurethane has an OH number less than 50.

12. The aqueous coating composition of claim 1 , further comprising a thickener, a leveling agent, a crosslinking agent, or mixtures thereof.

13. The aqueous coating composition of claim 1 , wherein the colloidal silica is present in an amount of from 7.5% to 15% by solids weight, based on the total solids weight of the colloidal silica and the polyurethane-acrylic polymer, and has an average particle size less than 50 nm;
wherein the polyurethane-acrylic polymer is present in an amount of from 85% to 92.5% by solids weight, based on the total solids weight of the colloidal silica and the polyurethane-acrylic polymer;
wherein the acrylic polymer has a Tg of from −10° C. to 0° C. and comprises as polymerized units, based on the weight of the acrylic polymer,
(i) from 1.5% to 2.5% by weight of an ethylenically difunctional or multifunctional compound selected Rom allyl (meth)acrylate, hexanediol di(meth)arcylate, ethylene glycol di(meth)acrylate, neopentyl glycol di(meth)acrylate, butanediol di(meth)acrylate, trimethylolpropane tri(meth)acrylate, or mixtures thereof; and
(ii) from 97.5% to 98.5% by weight of an ethylenically monofunctional compound selected from a (meth)acrylic acid alkyl ester; and
wherein the weight ratio of polyurethane to acrylic polymer in the polyurethane-acrylic polymer is from 60/40 to 35/75.

14. A method of preparing an aqueous coating composition of claim 1 , comprising: admixing colloidal silica and a polyurethane-acrylic polymer,
wherein the colloidal silica is present in an amount of from 5% to 30% by solids weight, based on the total solids weight of the colloidal silica and the polyurethane-acrylic polymer, and has an average particle size less than 150 nm;
wherein the polyurethane-acrylic polymer is present in an amount of from 70% to 95% by solids weight, based on the total solids weight of the colloidal silica and the polyurethane-acrylic polymer, and is obtained by forming an acrylic polymer in an aqueous medium by an emulsion polymerization in the presence of a polyurethane;
wherein the acrylic polymer having a Tg of from −13° C. to 10° C. comprises as polymerized units, based on the weight of the acrylic polymer,
(i) from 0.5% to 4% by weight of an ethylenically difunctional or multifunctional compound, and
(ii) from 96% to 99.5% by weight of an ethylenically monofunctional compound; and
wherein the weight ratio of polyurethane to acrylic polymer in the polyurethane-acrylic polymer is from 30/70 to 99/1.

Assignees

• Dow Global Technologies Llc
• Rohm & Haas

Inventors

• Zhan fu
• Li Caiyun
• Li Yaobang
• Zhang Jinyuan
• Feng Jiansheng
• Dong Xiangting
• Shen Qian

Classifications

• C08F283/006

  on to polymers provided for in C08G18/00 (C08F283/004 takes precedence) · CPC title

• C08F220/40

  Esters of unsaturated alcohols {, e.g. allyl (meth)acrylate} · CPC title

• C08F220/1804

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

• C08F220/14

  Methyl esters {, e.g. methyl (meth)acrylate} · CPC title

• C09D7/68

  Particle size between 100-1000 nm · CPC title