Process for the production of a dark-color multi-layer coating

• US 8,835,008 B2
• Filed: 05/27/2009
• Issued: 09/16/2014
• Est. Priority Date: 05/30/2008
• 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: Richter, Gunter, Dossel, Karl-Friedrich
• Primary Examiner(s): FLETCHER III, WILLIAM P
• Application Number:
  US12/993,122
• Publication Number:
  US 20110070427A1
• Time in Patent Office: 1,938 Days
• Field of Search: 427/407.1, 427/409, 427/419.1, 427/419.2, 428/411.1
• US Class Current: 428/411.1
• CPC Class Codes: B05D 1/02 performed by spraying
• CPC Class Codes: B05D 2202/10 based on Fe
• CPC Class Codes: B05D 3/0254 After-treatment
• CPC Class Codes: B05D 5/06 to obtain multicolour or other optical effects B05D5/02 takes precedence
• CPC Class Codes: B05D 7/542 the two layers being cured or baked together
• CPC Class Codes: B05D 7/572 all layers being cured or baked together
• CPC Class Codes: B05D 7/574 at least some layers being let to dry at least partially before applying the next layer B05D7/577 takes precedence
• CPC Class Codes: C08K 3/08 Metals
• CPC Class Codes: C08K 3/22 of metals
• CPC Class Codes: C09D 5/004 Reflecting paints; Signal paints
• CPC Class Codes: C09D 7/41 Organic pigments; Organic dyes
• CPC Class Codes: C09D 7/61 inorganic
• CPC Class Codes: C09D 7/70 characterised by shape, e.g. fibres, flakes or microspheres
• CPC Class Codes: Y10T 428/256 Heavy metal or aluminum or compound thereof
• CPC Class Codes: Y10T 428/31504 Composite [nonstructural laminate]

Abstract

A process for the production of a dark-color multi-layer coating, comprising the successive steps:

• (1) applying an NIR-opaque coating layer A′ from a pigmented, solvent- or waterborne coating composition A to a substrate,
• (2) applying a coating layer B′ from a pigmented coating composition B onto the substrate provided with coating layer A′,
• wherein the pigment content of coating composition A consists 90 to 100 wt. % of at least one 10 to 80 nm thick aluminum flake pigment and 0 to 10 wt. % of at least one further pigment, which is selected in such a way that NIR-opaque coating layer A′ exhibits low NIR absorption,
• wherein the pigment content of coating composition B consists 50 to 100 wt. % of at least one black pigment with low NIR absorption and 0 to 50 wt. % of at least one further pigment, which is selected in such a way that coating layer B′ exhibits low NIR absorption and that the dark-color multi-layer coating exhibits a brightness L* (according to CIEL*a*b*, DIN 6174), measured at an illumination angle of 45 degrees to the perpendicular and an observation angle of 45 degrees to the specular, of at most 10 units,
• wherein the sum of the respective wt. % equals 100 wt. %, and
• wherein the coating layers A′ and B′ are cured.

Claims

1. A process for the production of a dark-color multi-layer coating, comprising the successive steps:

(1) applying an NIR-opaque coating layer A′

from a pigmented, solvent- or waterborne coating composition A to a substrate,

(2) applying a coating layer B′

from a pigmented coating composition B onto the substrate provided with coating layer A′

,

wherein the pigment content of coating composition A consists 90 to 100 wt. % of at least one 10 to 80 nm thick aluminum flake pigment and 0 to 10 wt. % of at least one further pigment, and the pigment content of coating composition A is selected in such a way that NIR-opaque coating layer A′

exhibits an NIR reflection of at least 55% over the entire NIR wavelength range of 780 to 2100 nm,

wherein the pigment content of coating composition B consists 50 to 100 wt. % of at least one black pigment with low NIR absorption selected from the group consisting of iron oxide black pigments, mixed metal/iron oxide black pigments and perylene black pigments and 0 to 50 wt. % of at least one further pigment, and the pigment content of coating composition B is selected in such a way that coating layer B′

exhibits low NIR absorption and that the dark-color multi-layer coating exhibits a brightness L* (according to CIEL*a*b*, DIN

     6174), measured at an illumination angle of 45 degrees to the perpendicular and an observation angle of 45 degrees to the specular, of at most 10 units,

wherein the sum of the respective wt. % equals 100 wt. %, and

wherein the coating layers A′ and

B′

are cured.

2. The process of claim 1, wherein the pigment content of coating composition A consists exclusively of the at least one 10 to 80 nm thick aluminum flake pigment.

3. The process of claim 1, wherein coating composition A does not contain any carbon black.

4. The process of claim 1, wherein coating composition B does not contain any carbon black.

5. The process of claim 1, wherein coating layer B′

is a transparent or a visually opaque coating layer.

6. The process of claim 1 comprising a further successive step (3) of application and curing of a clear coat.

7. The process of claim 6, wherein coating layer A′

is cured in step (1) and coating layer B′ and

the clear coat layer applied in step (3) are jointly cured.

8. The process of claim 6, wherein coating layers A′

, B′ and

the clear coat layer applied in step (3) are jointly cured.

9. A substrate provided with a dark-color multi-layer coating produced by the process of claim 1.