Aqueous radiation curable polyurethane compositions

• US 9,163,111 B2
• Filed: 07/06/2009
• Issued: 10/20/2015
• Est. Priority Date: 07/10/2008
• Status: Active Grant

• Current Assignee: Allnex Belgium SA (Allnex Holding S.a r.l.)
• Original Assignee: Allnex Belgium SA (Allnex Holding S.a r.l.)
• Inventors: Van Holen, Jurgen, Cappelle, Steven, Deruyttere, Xavier, Tielemans, Michel
• Primary Examiner(s): NILAND, PATRICK DENNIS
• Application Number:
  US13/002,676
• Publication Number:
  US 20110112244A1
• Time in Patent Office: 2,297 Days
• Field of Search: 524/507, 524/589, 524/590, 524/591, 524/839, 524/840, 525/123, 525/455, 427/372.2, 427/385.5, 428/423.1, 428/425.1
• US Class Current: 1/1
• CPC Class Codes: B05D 2201/02 Polymeric substrate
• CPC Class Codes: B05D 2203/20 Wood or similar material
• CPC Class Codes: B05D 2401/20 Aqueous dispersion or solution
• CPC Class Codes: B05D 2503/00 Polyurethanes
• CPC Class Codes: B05D 3/06 by exposure to radiation B05D3/02 takes precedence ; plasma treatment B05D3/141
• CPC Class Codes: B32B 27/40 comprising polyurethanes
• CPC Class Codes: C08F 283/006 on to polymers provided for in C08G18/00 C08F283/004 takes precedence
• CPC Class Codes: C08F 283/008 on to unsaturated polymers
• CPC Class Codes: C08F 290/067 Polyurethanes; Polyureas
• CPC Class Codes: C08F 290/147 Polyurethanes; Polyureas
• CPC Class Codes: C08G 18/0823 containing carboxylate salt groups or groups forming them
• CPC Class Codes: C08G 18/348 Hydroxycarboxylic acids
• CPC Class Codes: C08G 18/673 containing two or more acrylate or alkylacrylate ester groups
• CPC Class Codes: C08G 18/73 acyclic
• CPC Class Codes: C09D 175/16 having terminal carbon-to-carbon unsaturated bonds

Abstract

The present invention relates to an aqueous composition comprising from 5 to 90% by weight of a polymerizable ethylenically unsaturated water dispersible polyurethane (A) and from 1 to 60% by weight relative to the weight of polyurethane (A) of a least one polymerizable ethylenically unsaturated compound (B) having a water solubility at 25° C. of less than 50 g/l, and it use for making high gloss coatings as well as wood stains.

Claims

1. An aqueous composition comprising:

from 5 to 90% by weight of a polymerizable ethylenically unsaturated water dispersible polyurethane (A) containing at least 0.2 meq/g of allophanate groups and obtained from the reaction of 10 to 60 weight % of at least one polyisocyanate (i), 3 to 25 weight % of at least one hydrophilic compound (ii) containing at least one reactive group capable to react with isocyanate groups and at least one group which is capable to render the polyurethane dispersible in aqueous medium either directly or after a reaction with a neutralizing agent to provide a salt, and 20 to 85 weight % of at least one polymerizable ethylenically unsaturated compound (iii) containing at least one reactive group capable to react with isocyanate groups; and

from 15 to 60% by weight relative to the weight of polyurethane (A) of at least one polymerizable ethylenically unsaturated compound (B) having a water solubility at 25°

C. of less than 50 g/l, wherein compound (B) is a (meth)acrylate with a weight average molecular weight of at most 1000.

2. The aqueous composition according to claim 1, wherein the polyurethane (A) is obtained by a process comprising the reaction of a stoichiometric excess of polyisocyanate (i) with polymerizable ethylenically unsaturated compound (iii), a second step comprising the reaction of the product of the first step with hydrophilic compound (ii) and a third step wherein the remaining free isocyanate groups provided by polyisocyanate (i) are reacted to give allophanate groups.

3. The aqueous composition according to claim 1, wherein the polyurethane (A) contains from 1 to 6 meq/g of ethylenically unsaturated double bonds.

4. The aqueous composition according to claim 1, wherein the polyisocyanate is selected from aliphatic and cycloaliphatic polyisocyanates.

5. The aqueous composition according to claim 1, wherein the hydrophilic compound (ii) is selected from a,a-dimethylolalkanoic acids.

6. The aqueous composition according to claim 1, wherein the polymerizable ethylenically unsaturated compound (iii) is selected from poly(meth)acrylolyl mono-hydroxy compounds.

7. The aqueous composition according to claim 1, wherein the polymerizable ethylenically unsaturated compound (B) has a water solubility at 25°

C. of less than 10 g/l.

8. The aqueous composition according to claim 1, wherein the polymerizable ethylenically unsaturated compound (B) is selected from (meth)acrylated compounds comprising at least two (meth)acryl groups and at most one other functional group.

9. The aqueous composition according to claim 8, wherein the (meth)acrylated compound comprising at least two (meth)acryl groups and at most one other functional group is selected from hexanediol di(meth)acrylate, trimethylolpropane tri(meth)acrylate, glycerol tri(meth)acrylate, pentaerythritol tri(meth)acrylate, pentaerythritol tetra(meth)acrylate, di-trimethylolpropane tetra(meth)acrylate, di-pentaerythritol hexa(meth)acrylate and mixtures thereof.

10. The aqueous composition according to claim 1, wherein the polymerizable ethylenically unsaturated compound (B) is selected from alkoxylated (meth)acrylated compounds.

11. The aqueous composition according to claim 10, wherein the alkoxylated (meth)acrylated compound is selected from the esterification products of (meth)acrylic acid with alkoxylated polyols comprising at least 2 hydroxyl groups and from 0.3 to 3 alkoxy groups per hydroxyl group.

12. A process for the preparation of a radiation-curable composition according to claim 1, said process comprising

a first step comprising the reaction of compounds (i) and (iii),

a second step, comprising the reaction of the product of the first step with a compound (ii),

a third step wherein the product obtained after the second step is further reacted until the residual isocyanate content is lower than 1 meq/g,

a fourth step comprising the dispersion in an aqueous medium of the polyurethane obtained after the third step,

an optional step comprising the reaction with a neutralizing agent in order to convert the hydrophilic groups provided by compound (ii) into anionic salts, and

a step comprising the addition of an ethylenically unsaturated compound (B).

13. A process for preparing a coated substrate or article, wherein the substrate or article is coated with a composition according to claim 1.

14. The process according to claim 13, wherein the substrate or article is a plastic or wood substrate or article, and wherein a composition according to claim 8 is used.

15. The process according to claim 13, wherein the substrate or article is a wood substrate or article, and wherein a composition according to claim 10 is used as a UV stain.

16. The aqueous composition according to claim 1, comprising

from 15 to 50% by weight relative to the weight of polyurethane (A) of a least one polymerizable ethylenically unsaturated compound (B) having a water solubility at 25°

C. of less than 50 g/l, wherein compound (B) is a (meth)acrylate with a weight average molecular weight of at most 1000.

17. The aqueous composition according to claim 1, comprising

from 25 to 50% by weight relative to the weight of polyurethane (A) of a least one polymerizable ethylenically unsaturated compound (B) having a water solubility at 25°

C. of less than 50 g/l, wherein compound (B) is a (meth)acrylate with a weight average molecular weight of at most 1000.