PROCESS FOR MULTILAYER COATING

• US 20120082799A1
• Filed: 06/14/2010
• Published: 04/05/2012
• Est. Priority Date: 06/12/2009
• Status: Active Grant

• Current Assignee: Axalta Coating Systems Ip Co Llc (Axalta Coating Systems Ltd.)
• Original Assignee: E. I. du Pont de Nemours and Company (Corteva, Inc.)
• Inventors: Loeffler, Helmut
• Granted Patent: US 9,186,701 B2
• Time in Patent Office: Days
• US Class Current: 427/496
• 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 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. 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 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.

2. 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. Process of claim 1, wherein the at least one organic phosphine derivative is a triaryl phosphine.

4. Process of claim 2, wherein the at least one organic phosphine derivative is triphenyl phosphine.

5. Process of claim 1, wherein the organic phosphine derivative is present in amounts of 0.5 to 45% by weight solids, based on the total amount of weight solids of component A).

6. Process of claim 5, wherein the organic phosphine derivative is present in amounts of 3.0 to 40% by weight solids, based on the total amount of weight solids of component A).

7. Process of claim 1, wherein the clear coat coating composition comprises

A) at least one compound capable of free-radical polymerization having at least one olefinically unsaturated group and optionally at least one functional group a) that is reactive towards the at least one functional group b) of compound A1) and/or A3),

A1) optionally at least one compound with at least one functional group b) curable by addition and/or condensation reaction,

A2) optionally at least one compound with at least one functional group a) that is reactive towards the at least one functional group b) of compound A1) and/or A3),

A3) optionally at least one further compound capable of free-radical polymerization having at least one olefinically unsaturated group and at least one functional group b) that is reactive towards the at least one functional group a) of compound A) and/or A2),

B) at least one photoinitiator and

C) at least on triphenyl phosphine derivative,

with the proviso that, component A) contains functional groups a) and/or component A2) with functional groups a) is present, and that at least one of components A1) and A3) with functional groups b) is present.

8. Process of claim 7, wherein the organic phosphine derivative is present in amounts of 0.5 to 45% by weight solids, based on the total amount of weight solids of component A) and of component A3), if present.

9. Process of claim 8, wherein the organic phosphine derivative is present in amounts of 0.5 to 45% by weight solids, based on the total amount of weight solids of component A) and of component A3), if present.

10. Process of claim 1, wherein the clear coat coating composition comprises

A) at least one compound capable of free-radical polymerization having at least one olefinically unsaturated group and optionally at least one functional group a) that is reactive towards the at least one functional group b) of compound A1),

A1) at least one compound with at least one functional group b) curable by addition and/or condensation reaction,

A2) optionally at least one compound with at least one functional group a) that is reactive towards the at least one functional group b) of compound A1),

B) at least one photoinitiator and

C) at least one triphenyl phosphine derivative,

with the proviso that, compound A) contains at least one functional group a) that is reactive towards the at least one functional group b) of compound A1), and/or component A2) with functional groups a) is present.

11. Process of claim 1, wherein the olefinically unsaturated groups are (meth)acryloyl groups.

12. Process of claim 7, wherein the functional groups a) are hydroxyl groups or isocyanate groups.

13. Process of claim 7, wherein the complementary functional groups b) are hydroxyl groups or isocyanate groups.

14. Process of claim 7, wherein component A) comprises at least one compound with functional groups a) with active hydrogen and component A1) comprises at least one compound with isocyanate groups b).

15. Process of claim 14, wherein component A) comprises at least one compound selected from the group consisting of a hydroxyl-functional (meth)acryloyl functional polyurethanes, hydroxyl-functional (meth)acryloyl functional urethane compounds, hydroxyl-functional (meth)acryloyl functional (meth)acrylic copolymers and mixtures thereof, and wherein component A1) comprises at least one polyisocyanate with free isocyanate groups.

16. Process of claim 1, wherein the clear coat coating composition is free of organic phosphites.

17. Process of any one of claims 1 to 16 for multi-layer coating of vehicle bodies and vehicle body parts.

18. Process of claim 1, wherein said substrate is vehicle body or vehicle body parts.