Process for coating a substrate with a radiation and moisture curable coating composition

• US 4,173,682 A
• Filed: 03/08/1978
• Issued: 11/06/1979
• Est. Priority Date: 03/09/1977
• Status: Expired due to Term

• Current Assignee: Akzo Nobel N.V. (Nouryon BV)
• Original Assignee: Akzo Nobel N.V. (Nouryon BV)
• Inventors: Noomen, Arie, Van Santen, Dick, van der Geest, Johannes M. P., de Jong, Cornelis
• Primary Examiner(s): Newsome, John H.
• Application Number:
  US05/884,588
• Time in Patent Office: 608 Days
• Field of Search: 427/44, 427/54, 560/26, 560/158, 260/18 TN, 528/68, 528/73, 96/35.1, 204/159.15
• US Class Current: 428/423.1
• CPC Class Codes: C08F 2/48 by ultraviolet or visible light
• CPC Class Codes: C08G 18/8175 with esters of acrylic or alkylacrylic acid having only one group containing active hydrogen
• CPC Class Codes: Y10T 428/31551 Of polyamidoester [polyurethane, polyisocyanate, polycarbamate, etc.]
• CPC Class Codes: Y10T 428/31855 Of addition polymer from unsaturated monomers

Abstract

A process is disclosed for coating a substrate with a radiation curble coating composition, characterized in that the composition comprises (A) an at least one isocyanate group-containing adduct of (a) an acrylic or methacrylic hydroxy ester with 5 to 20 carbon atoms and (b) a polyisocyanate with 4 to 40 carbon atoms and with 2 to 4 isocyanate groups per molecule, (B) a polyfunctional hydroxy compound having a molecular weight of 178 to 12,000 and a hydroxyl content of 0.5 to 30% by weight in an amount of 0.5 to 1.5 equivalents of hydroxy per equivalent of isocyanate of component A, and (C) a photoinitiator in an amount of 0.1 to 10% by weight of component A. The curing takes place in a first stage by radiation having a wavelength of 90 to 600 nm and in a second stage by reaction of the isocyanate groups of component A with water vapor and the hydroxyl groups of the polyfunctional hydroxy compound.

Claims

1. A process for coating a substrate by applying to it a radiation curable coating composition based on a urethane compound and subjecting it to radiation have a wavelength of 90 to 600 nm, characterized in that a composition comprising (A) an at least one isocyanate group-containing adduct of (a) an acrylic or methacrylic hydroxy ester with 5 to 20 carbon atoms and (b) a polyisocyanate with 4 to 40 carbon atoms and with 2 to 4 isocyanate groups per molecule, (B) a polyfunctional hydroxy compound having a molecular weight of 178 to 12,000 and a hydroxyl content of 0.5 to 30% by weight in an amount of 0.5 to 1.5 equivalents of hydroxy per equivalent of isocyanate of component A, and (C) a photoinitiator in an amount of 0.1 to 10% by weight of component A, is applied to the substrate, and the coating layer is subjected to radiation and mainly after radiation the adduct is reached with water vapour.

2. A process according to claim 1, characterized in that the acrylic or methacrylic hydroxy ester contains 5 to 15 carbon atoms.

3. A process according to claim 1 or 2, characterized in that 2-hydroxyethylacrylate, 4-hydroxybutylacrylate or pentaerythritoltriacrylate is used as acrylic or methacrylic hydroxy ester.

4. A process according to claim 1, characterized in that the polyisocyanate contains 15 to 40 carbon atoms.

5. A process according to claim 1, characterized in that the polyisocyanate contains 2 or 3 isocyanate groups per molecule.

6. A process according to claim 1, characterized in that as polyisocyanate there is used the adduct of 3 molecules of hexamethylene-1,6-diisocyanate and 1 molecule of water, the adduct of 1 molecule of trimethylol propane and 3 molecules of toluene diisocyanate or the adduct of 1 molecule of trimethylol propane and 3 molecules of isophoron diisocyanate.

7. A process according to claim 1, characterized in that in the composition there is present a polyfunctional hydroxy compound in an amount of 0.9 to 1.1 equivalents of hydroxy per equivalent of isocyanate of component A.

8. A process according to claim 1, characterized in that the polyfunctional hydroxy compound contained in the composition is a polyester polyol, a polyether polyol, an acrylate polyol or a polycaprolactone.

9. A process according to claim 1, characterized in that the composition contains a polyfunctional hydroxy compound having a molecular weight in the range of 300 to 8000.

10. A process according to claim 1, characterized in that the composition contains a polyfunctional hydroxy compound having a hydroxyl content of 1 to 22% by weight.

11. A substrate coated wit a cured coating composition obtained by the method according to any one of claims 1 and 4-10.

12. A process for coating a substrate with a composition containing a cross-linked urethane which comprises coating the substrate with a cross-linkable urethane composition comprising

A. an --NCO terminated ethylenically unsaturated adduct of an acrylic or methacrylic hydroxy ester having 5 to 20 carbon atoms and an organic polyisocyanate having 4 to 40 carbon atoms and from 2 to 4 isocyanate groups per molecule;

B. an organic polyhydroxy compound having a molecular weight of 178 to 12,000 and a hydroxyl content of 0.5 to 30% by weight, and

C. a photoinitiator

said mixture containing A and B in a ratio which provides 0.5 to 1.5 equivalents of hydroxy per equivalent of --NCO and containing from 0.1 to 10% by weight of C based on the weight of A,

polymerizing the adduct through its unsaturation with irradiation and subsequently reacting isocyanate groups of the resulting polymer with hydroxy groups of B.