Process for matching color and appearance of coatings

Patent metadata

Field	Value
Publication number	US-2016005187-A1
Application number	US-201414769840-A
Country	US
Kind code	A1
Filing date	Feb 26, 2014
Priority date	Feb 26, 2013
Publication date	Jan 7, 2016
Grant date	—

Abstract

A process for producing a total match metric for matching color and appearance of a target coating and at least a specimen coating is provided. The total match metric (TMM) are produced based on color difference values (ΔE) at three or more color viewing angles, sparkle difference values (ΔS) at one or more sparkle viewing angles and flop difference value (Δf) between the target coating and the specimen coating using one or more linear functions, one or more non-linear functions, or a combination thereof. The total match metric can be used in producing matching coatings that match color and appearance of the target coating. The total match metric can be particularly useful for repair coating damages to vehicles.

First claim

1 . A process for producing a total match metric for matching color and appearance of a target coating and at least a specimen coating, the process comprising the steps of:
A1) obtaining target color data of the target coating and specimen color data of the specimen coating produced from a specimen coating composition, wherein the target color data comprise target color values measured at three or more color viewing angles and the specimen color data comprise specimen color data values measured at the three or more color viewing angles; A2) producing color difference values (ΔE) at each of the color viewing angles based on the target color data and the specimen color data values at each of the color viewing angles; A3) obtaining target sparkle data of the target coating and specimen sparkle data of the specimen coating, wherein the target sparkle data comprise target sparkle values measured at one or more sparkle viewing angles and the specimen sparkle data comprise specimen sparkle values measured at the one or more sparkle viewing angles; A4) producing sparkle difference values (ΔS) at each of the sparkle viewing angles based on the target sparkle data and the specimen sparkle data at each of the sparkle viewing angles; A5) generating target flop data (f t ) of the target coating based on target lightness value derived from the target color data and specimen flop data (f s ) of the specimen coating based on a specimen lightness value derived from the specimen color data; A6) producing a flop difference value (Δf) based on the target flop data and the specimen flop data; and A7) producing the total match metric (TMM) of the target coating and the specimen coating based on the color difference values (ΔE), the sparkle difference values (ΔS) and the flop difference value (Δf).

2 . The process of claim 1 , wherein the total match metric (TMM) is produced according to Formula (I):
TMM=f[ΔE A1 ,ΔE A2 ,ΔE A3 ,Δf,ΔS P1 ,ΔS P2 ]  (I);
wherein, ΔE A1 is a color difference value at color viewing angle A 1 , ΔE A2 is a color difference value at color viewing angle A 2 , ΔE A3 is a color difference value at color viewing angle A 3 , Δf is the flop difference value based on the target flop data (f t ) and the specimen flop data (f s ); ΔS P1 is a sparkle difference value at sparkle viewing angle P 1 , ΔS P2 is a sparkle difference value at sparkle viewing angle P 2 ; the target flop data (f t ) is produced according to Formula (II-a):
f t =g ( L t A1 −L t A3 ) g′ /( L t A2 ) g″   (II-a);

the specimen flop data (f s ) is produced according to Formula (II-b):
f s =g ( L s A1 −L s A3 ) g′ /( L s A2 ) g″   (II-b);

g is a number in a range of from about 1 to about 6,
g′ is a number in a range of from about 1 to about 3, and
g″ is a number in a range of from about 0.1 to about 2,
L t A1 is the target lightness value derived from the target color data at the color viewing angle A 1 ,
L t A2 is the target lightness value derived from the target color data at the color viewing angle A 2 ,
L t A3 is the target lightness value derived from the target color data at the color viewing angle A 3 ,
L s A1 is the specimen lightness value derived from the specimen color data at the color viewing angle A 1 ,
L s A2 is the specimen lightness value derived from the specimen color data at the color viewing angle A 2 ,
L s A3 is the specimen lightness value derived from the specimen color data at the color viewing angle A 3 ;
the flop difference value (Δf) is produced according to Formula (III), (IV) or (V):
Δ f =( f s −f t )/ f t , when f t <z   (III)

Δ f =( f s −z )/ z , when f t ≧z and f s <z   (IV)

Δ f= 0, when f t ≧z and f s ≧z   (V),

z is a number in a range of from about 12 to about 20;
the sparkle difference values are produced according to Formula (VI) and (VII):
Δ S P1 =f ( S t P1 ,S s P1 )  (VI)

Δ S P2 =f ( S t P2 ,S s P2 )  (VII),

S t P1 is the target sparkle data at the sparkle viewing angle P 1 ,
S s P1 is the specimen sparkle data at the sparkle viewing angle P 1 ,
S t P2 is the target sparkle data at the sparkle viewing angle P 2 , and
S s P2 is the specimen sparkle data at the sparkle viewing angle P 2 ;
wherein the color viewing angles are aspecular angles A 1 in a range of from about 50 to about 25°, A 2 in a range of from about 30° to about 90° and A 3 in a range of from about 95° to about 165°; and the sparkle viewing angles are aspecular angles P 1 in a range of from about 5° to about 25° and P 2 in a range of from about 30° to about 90°.

3 . The process of claim 2 , wherein the Formula (I) is:
TMM=X 1 +X 2 +X 3 +X 4 +X 5 +X 6   (I-a),
wherein, X 1 =((ΔE A1 ) n )/m, n is a number in a range of from about 0.1 to about 2, m is a number in a range of from about 1 to about 5; X 2 =((ΔE A2 ) n′ )/m′, n′ is a number in a range of from about 0.1 to about 2, m′ is a number in a range of from about 1 to about 5; X 3 =(ΔE A3 ) n″ /m″, n″ is a number in a range of from 0.1 to 2, m″ is a number in a range of from about 1 to about 5; X 4 =((a|(Δf−b)|) q /p, when Δf≧0; or X 4 =((a|(−Δf+b)|) q /p, when Δf<0, a is a number in a range of from about 1 to about 5, b is a number in a range of from about 0.001 to about 0.1, p is a number in a range of from about 2 to about 20, q is a number in a range of from about 1 to about 5; X 5 =(|ΔS P1 |) r /S t P1 , when ΔS P1 ≧0; or X 5 =c(|ΔS P1 |) r /S t P1 , when ΔS P1 <0; S t P1 is the target sparkle data at the sparkle viewing angle P 1 , r is a number in a range of from about 1 to about 3, c is a number in a range of from about 1.1 to about 6; and X 6 =d(|ΔS P2 |) r′ /S t P2 , when ΔS P2 ≧0; or X 6 =d′(|ΔS P2 |) r′ /S t P2 , when ΔS P2 <0; S t P2 is the target sparkle data at the sparkle viewing angle P 2 , r′ is a number in a range of from about 1 to about 3, d is a number in range of from about 1.10 to about 6, d′ is a number in a range of from about 1.11 to about 8, and d′>d.

4 . The process of claim 2 , wherein the Formula (I) is:
TMM=k ( X′ 1 +X′ 2 +X′ 3 +X′ 4 +X′ 5 +X′ 6 )  (I-b)
wherein: k is a predetermined constant, X′ 1 =α(ΔE A ), α is a number in a range of from about 0.1 to about 6, X′ 2 =β((ΔE A2 ), β is a number in a range of from about 0.1 to about 6, X′ 3 =γ(ΔE A3 ), γ is a number in a range of from about 0.1 to about 6, X′ 4 =((λ|(Δf)|) ε /10, λ is a number in a range of from about 1 to about 6, ε is a number in a range of from about 1 to about 6, X′ 5 =|ΔS P1 |/S t P1 , and X′ 6 =|ΔS P2 |/S t P2 .

5 . The process of claim 2 , wherein the Formula (I) is:
TMM=k 1 ( k 2 ( X″ 1 +k 3 ( X″ 5 ) y 1 +( k 4 ( X″ 2 +k 5 ( X″ 6 )) y 2 +k 6 ( X″ 3 ) y 3 +X″ 4 )  (I-c),
wherein: k 1 is a number in a range of from about 0.1 to about 6, k 2 is a number in a range of from about 0.1 to about 3, k 3 is a number in a range of from about 1 to about 20, k 4 is a number in a range of from about 0.1 to about 3, k 5 is a number in a range of from about 0.1 to about 3, k 6 is a number in a range of from about 0.1 to about 3, y 1 is a number in a range of from about 0.1 to about 3, y 2 is a number in a range of from about 1 to about 6, y 3 is a number in a range of from about 1 to about 6, X″ 1 =α(ΔE A1 ), α is a number in a range of from about 0.1 to about 6, X″ 2 =β(ΔE A2 ), β is a number in a range of from about 0.1 to about 6, X″ 3 =γ(ΔE A3 ), γ is a number in a range of from about 0.1 to about 6, X″ 4 =((λ|(Δf)|) ε /10, λ is a number in a range of from about 1 to about 6, ε is

Assignees

• Axalta Coating Systems Ip Co
• Axalta Coating Systems Ip Co

Inventors

• Prakash Arun

Classifications

• G06T7/408 Primary

  Physics · mapped topic

• G01N21/4738

  Diffuse reflection (precedence is given to G01N21/55 - G01N21/57 if specular component is taken into consideration), e.g. also for testing fluids, fibrous materials · CPC title

• G01N21/8422

  Investigating thin films, e.g. matrix isolation method · CPC title

• G06T2207/30248

  Vehicle exterior or interior · CPC title

• G01J3/463

  Colour matching · CPC title