# US 8,784,941 B2 · Process for the production of a dark-color multi-layer coating

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- Number: US 8,784,941 B2
- Document ID: US8784941B2
- Status: Granted
- Kind: B2
- Application number: 13/063,207
- Filed: 2009-09-14
- Published: 2011-07-14
- Granted: 2014-07-22
- Earliest claimed: 2008-09-15
- Assignees: Axalta Coating Systems IP Co., LLC
- Applicants: Gunter Richter; Karl-Friedrich Doessel; Wilfried Dutt
- Inventors: Gunter Richter; Karl-Friedrich Doessel; Wilfried Dutt
- Web page: https://patentgrep.com/patent/US8784941B2

## CPC

- B05D 7/574: {at least some layers being let to dry at least partially before applying the next layer (B05D7/577 takes precedence)}
- B05D 7/14: to metal, e.g. car bodies (involving a chemical reaction between the metal and the coating C23)
- C09D 7/61: inorganic
- C09D 7/70: {characterised by shape, e.g. fibres, flakes or microspheres}
- B05D 1/02: performed by spraying
- B05D 7/572: {all layers being cured or baked together}
- B05D 2202/10: based on Fe
- C08K 3/08: Metals
- C08K 3/22: of metals
- C08K 5/01: Hydrocarbons {(C08K5/0091 takes precedence)}
- B05D: PROCESSES FOR APPLYING FLUENT MATERIALS TO SURFACES, IN GENERAL (conveying articles or workpieces through baths of liquid B65G, e.g. B65G49/02)
- C09D: COATING COMPOSITIONS, e.g. PAINTS, VARNISHES OR LACQUERS; FILLING PASTES; CHEMICAL PAINT OR INK REMOVERS; INKS; CORRECTING FLUIDS; WOODSTAINS; PASTES OR SOLIDS FOR COLOURING OR PRINTING; USE OF MATERIALS THEREFOR (cosmetics A61K; processes for applying liquids or other fluent materials to surfaces, in general, B05D; staining wood B27K5/02; glazes or vitreous enamels C03C; natural resins, French polish, drying-oils, driers, turpentine, per se, C09F; polishing compositions other than French polish, ski waxes C09G; adhesives or use of materials as adhesives C09J; materials for sealing or packing joints or covers C09K3/10; materials for stopping leaks C09K3/12; processes for the electrolytic or electrophoretic production of coatings C25D)
- C08K: Use of inorganic or non-macromolecular organic substances as compounding ingredients (paints, inks, varnishes, dyes, polishes, adhesives C09)

## 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 waterborne pigmented coating composition A to a substrate, (2) applying a coating layer B′ from a waterborne pigmented coating composition B onto the substrate provided with coating layer A′, (3) subjecting the coated substrate obtained in step (2) to a drying step, (4) applying a clear coat layer, and (5) curing the coating layers simultaneously; wherein both coating compositions A and B comprise aqueous microgel and sheet silicate, wherein the pigment content of coating composition A comprises <90 wt. % of aluminum flake pigments and has such a composition that coating layer A′ exhibits low NIR absorption, wherein the pigment content of coating composition B consists 50 to 100 wt. % of black pigment with low NIR absorption and 0 to 50 wt. % of further pigment.

## Claims

### Claim 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 waterborne pigmented coating composition A to a substrate,
(2) applying a coating layer B′ from a waterborne pigmented coating composition B onto the substrate provided with coating layer A′,
(3) subjecting the coated substrate obtained in step (2) to a drying step,
(4) applying a clear coat layer from a clear coat composition onto the coated substrate obtained in step (3), and
(5) curing the coating layers applied in steps (1), (2), and (4) simultaneously;
wherein both waterborne coating compositions A and B comprise aqueous microgel and sheet silicate,
wherein the pigment content of coating composition A comprises <90 wt. % of aluminum flake pigments and is composed 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, and
wherein the sum of the respective wt. % equals 100 wt. %.

### Claim 2 (depends on 1)

The process of claim 1, wherein the pigment content of coating composition A comprises less than 25 wt. % of aluminum flake pigments.

### Claim 3 (depends on 1)

The process of claim 1, wherein coating composition A is a solid color coating composition free of special effect pigments.

### Claim 4 (depends on 1, 2, 3)

The process of claim 1, 2 or 3, wherein the pigment content of coating composition A comprises 80 to 100 wt. % of titanium dioxide.

### Claim 5 (depends on 4)

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

### Claim 6 (depends on 4)

The process of claim 4, wherein coating composition A comprises a binder solids comprising 30 to 100 wt. % of aqueous microgel.

### Claim 7 (depends on 4)

The process of claim 4, wherein coating composition A comprises 0.1 to 1.6 wt. % sheet silicate.

### Claim 8 (depends on 4)

The process of claim 4, wherein the at least one black pigment with low NIR absorption is selected from the group consisting of iron oxide black pigments, mixed metal/iron oxide black pigments and perylene black pigments.

### Claim 9 (depends on 4)

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

### Claim 10 (depends on 4)

The process of any claim 4, wherein coating composition B comprises a binder solids comprising 30 to 100 wt. % of aqueous microgel.

### Claim 11 (depends on 4)

The process of claim 4, wherein coating composition B comprises 0.1 to 1.6 wt. % sheet silicate.

### Claim 12 (depends on 4)

The process of claim 4, wherein coating layer B′ is a transparent or a visually opaque coating layer.

### Claim 13 (depends on 4)

The process of claim 4, wherein coating composition B is applied to coating layer A′ when at least 50 wt. % of the volatiles of coating composition A are still present in coating layer A′.

### Claim 14 (depends on 4)

The process of claim 4, wherein coating composition B is applied within 10 to 300 seconds of the application of coating composition A.

### Claim 15 (depends on 4)

The process of claim 4 being carried out in the context of an industrial mass production coating process.