Waterborne coating composition

Patent metadata

Field	Value
Publication number	US-10597553-B2
Application number	US-201214004423-A
Country	US
Kind code	B2
Filing date	Mar 26, 2012
Priority date	Mar 25, 2011
Publication date	Mar 24, 2020
Grant date	Mar 24, 2020

Abstract

The invention relates to an aqueous dispersion for use as open time improver in a coating composition which aqueous polymer dispersion comprises a first polymer having a number average molecular weight (Mn) of from 2,000 to 120,000 (determined by gel permeation chromatography using a mixture of tetrahydrofurane and acetic acid as eluent), an acid value of from 30 to 150 mg KOH/g, and an ethylene-oxide wt % (on total solid polymer) of from 1 to 20 wt %, said first polymer dispersion being obtainable by free radical polymerization of a monomer mixture in the presence of at least one free-radical initiator and at least one surfactant, said monomer mixture comprising: a) 5 to 20 wt %, preferably 7 to 10 wt %, acid functional ethylenically unsaturated monomers or precursors thereof or ethylenically unsaturated monomers comprising ionic group precursors; b) 5 to 25 wt %, preferably 7 to 20 wt %, ethylenically unsaturated monomers containing polyethylene oxide, polyethylene glycol or mono-alkoxypolyethylene glycol moeity c) up to 90 wt % of non-ionic ethylenically unsaturated monomers other than a) or b); d) 0 to 10 wt % ethylenically unsaturated monomers with a functional group for cross-linking e) 0 to 10 wt % of chain transfer agents; f) up to 90 wt % non-ionic ethylenically unsaturated monomers other than c), wherein 30 to 90 wt %, more preferably 60 to 80 wt % comprise crosslinkable groups or precursors thereof; wherein the sum of a) through f) is 100 wt %. The invention further relates to a method for making the first polymer dispersion, the use of said aqueous dispersion as an open time improver in a coating composition, to aqueous coating compositions comprising a blend of at least a first aqueous polymer dispersion and a second aqueous polymer dispersion comprising a film-forming second polymer and to a method for making said coating composition.

First claim

What is claimed is:

1. An aqueous dispersion, for use in a coating composition comprising:
a blend of at least a first aqueous polymer dispersion particles and a second aqueous polymer dispersion particles forming the aqueous dispersion,
wherein the particles of the first aqueous polymer dispersion are distinct from the particles of the second polymer dispersion in the aqueous dispersion,
wherein the weight ratio, calculated on solid polymer, of the first to the second polymer is 40/60 to 60/40,
wherein the first aqueous polymer dispersion comprises a first polymer having a number average molecular weight (Mn) of from 4,000 to 12,000 determined by gel permeation chromatography using a mixture of tetrahydrofuran and acetic acid as eluent, an acid value of from 30 to 150 mg KOH/g, a glass transition temperature Tg of at least 20° C. as calculated with the Fox formula, and an ethylene-oxide wt % based on total solid polymer of from 1 to 20 wt %, said first polymer dispersion obtained by free radical aqueous emulsion polymerization of a monomer mixture in the presence of at least one free-radical initiator and at least one surfactant, said monomer mixture comprising:
a) 5 to 20 wt % acid functional ethylenically unsaturated monomers or precursors thereof or ethylenically unsaturated monomers comprising ionic group precursors;
b) 5 to 25 wt %, ethylenically unsaturated monomers containing a mono-alkoxypolyethylene glycol moiety;
c) up to 90 wt % of non-ionic ethylenically unsaturated monomers other than a) or b);
d) 0 to 10 wt % ethylenically unsaturated monomers with a carbonyl functional group;
e) 0 to 10 wt % of chain transfer agents;
wherein the sum of a) through e) is 100 wt %;
wherein the second polymer is an aqueous vinyl polymer dispersion bearing carbonyl groups for cross-linking with a carbonyl reactive cross-linker, or an auto-oxidisable organic polymer containing unsaturated fatty acid;
wherein the aqueous dispersion is cross-linkable within a temperature range from 0° C. to 60° C.

2. The aqueous dispersion according to claim 1 , wherein the surfactant is a reactive surfactant comprising a free radically reactive double bond.

3. The aqueous dispersion according to claim 1 , wherein the ionic ethylenically unsaturated monomers or precursors a) comprise carboxylic acid groups or carboxylic acid precursors, sulphonic or phosphonic acid groups, or combinations thereof.

4. The aqueous dispersion according claim 1 , wherein the non-ionic ethylenically unsaturated monomers c) comprise:
i. up to 100 wt % styrene and/or styrene derivatives;
ii. up to 100 wt % of one or more non-ionic(meth)acrylic monomers;
iii. up to 25 wt % vinyl monomers containing oxidative cross linking groups;
iv. up to 10 wt % vinyl monomers containing self cross linkable groups;
v. up to 15 wt % vinyl monomers containing hydroxyl groups;
vi. up to 5 wt % vinyl monomers containing wet adhesion promoters wherein the sum of the weight of monomers i-vi=100 wt % of non-ionic ethylenically unsaturated monomers c).

5. The aqueous dispersion according claim 1 , wherein the first polymer has a number average molecular weight (Mn) of from 4,000 to 12,000 and has a polydispersity of 1.2 to 3.

6. The aqueous dispersion according to claim 1 , wherein the first polymer has a Tg in the range 20 to 80° C.

7. The aqueous dispersion according to according to claim 1 , wherein the acid functional groups of the first polymer are neutralized to an alpha value of from 0.05 to 0.70 and wherein the pH is from 6.0 to 8.0.

8. The aqueous dispersion of claim 3 , wherein the ionic ethylenically unsaturated monomers or precursors a) comprise methacrylic acid, acrylic acid, itaconic acid, maleic acid or anhydride, citraconic acid, or fumaric acid.

9. The aqueous dispersion according to claim 1 , wherein the second aqueous polymer dispersion comprises a film-forming second polymer.

10. The aqueous dispersion according to claim 9 , wherein the film forming second polymer in the second aqueous polymer dispersion is a vinyl polymer, polyurethane, alkyd, or combinations thereof.

11. The aqueous dispersion according to claim 1 , having a pH of from 2.0 to 9.0.

12. The aqueous dispersion according to claim 1 , wherein the second polymer has a weight average molecular weight, Mw, of from 20,000 to 2,000,000.

13. The aqueous dispersion according to claim 1 , wherein the second polymer has a glass transition temperature Tg of from −30° C. to 80° C.

14. The aqueous dispersion according to claim 1 , wherein the first polymer and second polymer have functional groups for co-crosslinking.

15. The aqueous dispersion according to claim 1 , comprising less than 20 wt % volatile organic solvent.

16. The aqueous dispersion according to claim 1 , wherein the second polymer is an auto-oxidisable polyurethane containing unsaturated fatty acid residues or an alkyd- or urethane modified alkyd emulsion.

17. The aqueous dispersion according to claim 2 , wherein the free radically reactive double bond, has a general structure M + -OOC—CH═CHCOOR, RO—(CH2-CH2-O)n-R1 or RO—(CH2-CH2-O)n-X or blends thereof, wherein R1 is an alkyl or hydrogen group, wherein X is an anionic group and wherein R is an organic group comprising: an allylic or maleic free radically reactive double bond and an alkyl, aryl or aralkyl group containing at least 8 carbons; and n is an integer from 0 to 50, and M + is a cation.

18. The aqueous dispersion according to claim 17 , wherein X is a sulphate or phosphate salt and n is an integer from 3 to 8 and M + is Na + , K + , Li + , NH 4 + or a protonated or quaternary amine.

19. The aqueous dispersion according to claim 1 , wherein the aqueous dispersion further comprises a dryer catalyst.

20. The aqueous dispersion according to claim 19 , wherein the dryer catalyst is a cobalt, manganese or iron complex.

Assignees

• Akkerman Jaap Michiel
• Mestach Dirk Emiel Paula
• Pilaszek Wincerty Lambertus Stanislaw
• Adolphs Rob
• Allnex Netherlands Bv

Inventors

• Akkerman Jaap Michiel
• Mestach Dirk Emiel Paula
• Pilaszek Wincerty Lambertus Stanislaw
• Adolphs Rob

Classifications

• C08G18/0823

  containing carboxylate salt groups or groups forming them · CPC title

• C08G18/69

  Polymers of conjugated dienes {(hydrogenated polymers of conjugated dienes C08G18/6208)} · CPC title

• C08G18/348

  Hydroxycarboxylic acids · CPC title

• C09D175/14

  Polyurethanes having carbon-to-carbon unsaturated bonds · CPC title

• C09D151/08

  grafted on to macromolecular compounds obtained otherwise than by reactions only involving carbon-to-carbon unsaturated bonds · CPC title