Process for multilayer coating

• US 9,186,701 B2
• Filed: 06/14/2010
• Issued: 11/17/2015
• Est. Priority Date: 06/12/2009
• Status: Active Grant

• Current Assignee: Axalta Coating Systems Ip Co Llc (Axalta Coating Systems Ltd.)
• Original Assignee: Axalta Coating Systems Ip Co Llc (Axalta Coating Systems Ltd.)
• Inventors: Loeffler, Helmut
• Primary Examiner(s): LIGHTFOOT, ELENA TSOY
• Application Number:
  US13/377,213
• Publication Number:
  US 20120082799A1
• Time in Patent Office: 1,982 Days
• Field of Search: 427/496
• US Class Current: 1/1
• CPC Class Codes: B05D 3/067 Curing or cross-linking the coating
• CPC Class Codes: B05D 7/532 the two layers being cured or baked together, i.e. wet on wet
• CPC Class Codes: C08K 5/50 Phosphorus bound to carbon only

Abstract

This invention relates to a process for multilayer coating of substrates, comprising the steps: I) applying a layer of a water-based color-imparting and/or special effect-imparting base coat coating composition to a substrate, II) applying a layer of a clear coat coating composition curable by means of high energy radiation and optionally curable by at least one additional chemical curing reaction, and III) curing said clear coat layer by exposing it to high energy radiation, wherein the clear coat coating composition comprises: A) at least one compound capable of free-radical polymerization having at least one olefinically unsaturated group, B) at least one photoinitiator and C) at least one organic phosphine derivative.

Claims

1. A process for multilayer coating of substrates, comprising the steps:

I) applying a layer of a water-based color-imparting and/or special effect-imparting base coat coating composition to a substrate,

II) applying a layer of a clear coat coating composition curable by means of high energy radiation, and

III) curing the clear coat layer by exposing it to high energy radiation, wherein the clear coat coating composition comprises;

A) a hydroxyl-functional (meth)acryloyl functional polyurethane compound, a hydroxyl-functional (meth)acryloyl functional urethane compound, and a hydroxyl-functional (meth)acryloyl functional (meth)acrylic copolymer,

A1) a polyisocyanate with free isocyanate groups,

B) at least one photoinitiator, and

C) triphenyl phosphine, wherein the clear coat coating composition comprises 3.0 to 40% by weight triphenyl phosphine.

2. The process of claim 1, wherein the clear coat coating composition curable by means of high energy radiation is in addition curable by at least one additional chemical curing reaction.

3. The process of claim 1, wherein the clear coat coating composition further comprises a triaryl phosphine.

4. The process of claim 2, wherein the clear coat coating composition further comprises a triaryl phosphine.

5. The process of claim 1, wherein the triphenyl phosphine is present in amounts of 5.0 to 30% by weight solids, based on the total amount of weight solids of component A).

6. The process of claim 1, wherein the triphenyl phosphine is present in amounts of about 20% by weight solids, based on the total amount of weight solids of component A).

7. The process of claim 1, wherein the clear coat coating composition further comprises:

A3) at least one compound capable of free-radical polymerization having at least one olefinically unsaturated group and at least one isocyanate group.

8. The process of claim 7, wherein the triphenyl phosphine is present in amounts of 5.0 to 20% by weight solids, based on the total amount of weight solids of component A) and of component A3).

9. The process of claim 8, wherein the triphenyl phosphine is present in amounts of about 10% by weight solids, based on the total amount of weight solids of component A) and of component A3).

10. The process of claim 1, wherein the clear coat coating composition further comprises:

A2) at least one compound with at least one hydroxyl group.

11. The process of claim 1, wherein the clear coat coating composition is free of organic phosphites.

12. The process of claim 1, wherein the substrate comprises a vehicle body or vehicle body parts.

13. The process of claim 1, wherein the photoinitiator is present in amounts of 0.4 to 3.0% by weight, based on the total amount of weight of the clear coat coating composition.