Method of producing matched coating composition and device used therefor

• US 20060181707A1
• Filed: 05/06/2004
• Published: 08/17/2006
• Est. Priority Date: 05/07/2003
• 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: Gibson, Mark Alan, Rodrigues, Allan Blase Joseph, Ward, Michelle Grace, Griffus, David Lee
• Granted Patent: US 7,466,415 B2
• Time in Patent Office: Days
• US Class Current: 356/402
• CPC Class Codes: B01F 33/84 Mixing plants with mixing receptacles receiving material dispensed from several component receptacles, e.g. paint tins
• CPC Class Codes: B01F 33/846 using stored recipes for determining the composition of the mixture to be produced, i.e. for determining the amounts of the basic components to be dispensed from the component receptacles
• CPC Class Codes: B01F 35/20 Measuring; Control or regulation
• CPC Class Codes: B01F 35/2131 Colour or luminescence
• CPC Class Codes: G01J 3/46 Measurement of colour; Colour measuring devices, e.g. colorimeters measuring colour temperature G01J5/60
• CPC Class Codes: G01J 3/463 Colour matching
• CPC Class Codes: G01J 3/465 taking into account the colour perception of the eye; using tristimulus detection
• CPC Class Codes: G01N 2021/8427 Coatings
• CPC Class Codes: G01N 21/25 Colour; Spectral properties, i.e. comparison of effect of material on the light at two or more different wavelengths or wavelength bands
• CPC Class Codes: G01N 21/251 Colorimeters; Construction thereof
• CPC Class Codes: G01N 21/55 Specular reflectivity
• CPC Class Codes: G01N 21/57 Measuring gloss
• CPC Class Codes: G01N 21/8422 Investigating thin films, e.g. matrix isolation method
• CPC Class Codes: G01N 2201/0221 Portable; cableless; compact; hand-held

Abstract

The present invention is directed to a method and device that use spectral measurements of the color of a target coating on a substrate, such as auto body being matched. The method utilizes pigment mixture models to produce a matched coating composition that when applied as a coating matches in appearance with that of the target coating, while also providing other desired coating properties, such as durability, gloss and adhesion. Various colorant combinations are analyzed to produce approximate spectral curves that substantially match the spectral curve of the target color. A colorant optimization function is then used to identify the optimum formula. This function utilizes acceptability factors, such as closeness of match based on a color tolerance formula, metamerism indices, shape of spectral curves, cost, and pigment durability. Each factor is weighted according to the specific end-use of the composition. The method of the present invention is well suited for producing automotive refinish paints used in automotive refinish applications wherein the undamaged portion of the autobody is color matched to produce a matched refinish paint that can be then applied over a repaired portion of autobody.

Claims

1. A method for producing a matched coating composition for a specified end-use, said method comprising:

(i) measuring reflectances of a target portion of a target coating at a set of preset wavelengths with a spectrophotometer of a coating characterizing device to plot a target spectral curve of said target portion;

(ii) calculating target color (L,a,b or L,C,h) values of said target portion from said target spectral curve of said target portion;

(iii) selecting one or more preliminary colorant combinations from a stored list of known colorants in accordance with a combinatorial selection criteria to match with said target color values;

(iv) determining concentration of each said known colorant in each of said preliminary colorant combinations in accordance with color matching criteria wherein said concentration of each said known colorant is optimized for optimal match of color values of each of said preliminary colorant combinations with said target color values;

(v) balancing said preliminary colorant combinations to allow for the presence of non-colorant components in said matched coating composition to generate one or more viable combinations optimized in accordance with mixing and regulatory criteria developed for said specified end-use; and

(vi) selecting an optimal viable combination from said viable combinations in accordance with an acceptability equation for said specified end-use, said optimal viable combination having an optimal acceptability value for said specified end-use wherein said known colorants and non-colorant components when mixed in accordance with said optimal viable combination produce said matched coating composition that when applied as a matched coating visually matches with the appearance of said target coating.

2. The method of claim 1 further comprising displaying on a screen of a monitor of said device said optimal viable combination.

3. The method of claim 1 further comprising mixing said components of said optimal viable combination to produce said matched coating composition.

4. The method of claim 1 further comprising applying said matched coating composition over a substrate to produce said coating that visually matches the appearance of said target coating.

5. The method of claim 4 wherein said substrate is an automotive body.

6. The method of claim 1 wherein said matched coating composition is an OEM automotive paint, refinish automotive paint, architectural paint, industrial coating composition, powder coating composition, printing ink, ink jet ink, nail polish, food colorant, eye shadow, or hair dye.

7. The method of claim 1 wherein each of said preliminary colorant combinations comprising one to seven said known colorants.

8. The method of claim 1 wherein said step (ii) comprises:

(a) directing a beam of light of a known intensity towards said target portion; and

(b) sequentially measuring at at least one aspecular angle said reflectances of said target portion at said set of preset wavelengths.

9. The method of claim 1 wherein said step (ii) comprises:

(a) sequentially directing one or more beams of light of a known intensity at at least one incident angle towards said target portion; and

(b) sequentially measuring at an aspecular angle said reflectances of said target portion at said set of preset wavelengths.

10. A matched coating composition produced by the method of claim 1.

16. A portable computer usable storage medium having said computer readable program code means of claim 1 stored therein.

17. The portable computer usable storage medium of claim 8 wherein said medium is a CD-Rom.

11. A color characterizing device for producing a matched coating composition for a specified end-use, said device comprising:

(i) a spectrophotometer of said device having a base for positioning said spectrophotometer over a target portion of a target coating;

(ii) means for calculating target color (L,a,b or L,C,h) values of said target portion;

(iii) a computer usable storage medium located in a computer of said device having computer readable program code means residing therein, said computer readable program code means comprising;

(a) means for configuring computer readable program code devices to cause said computer to select one or more preliminary colorant combinations from a stored list of known colorants in accordance with a combinatorial selection criteria to match with said target color space values;

(b) means for configuring computer readable program code devices to cause said computer to determine concentration of each said known colorant in each of said preliminary colorant combinations in accordance with color matching criteria wherein said concentration of each said known colorant is optimized for optimal match of color values of each of said preliminary colorant combinations with said target color values;

(d) means for configuring computer readable program code devices to cause said computer to balance said preliminary colorant combinations to allow for the presence of non-colorant components in said matched coating composition to generate one or more viable combinations optimized in accordance with mixing and regulatory criteria developed for said specified end-use; and

(e) means for configuring computer readable program code devices to cause said computer to select an optimal viable combination from said viable combinations in accordance with an acceptability equation for said specified end-use, said optimal viable combination having an optimal acceptability value for said specified end-use wherein said known colorants and non-colorant components when mixed in accordance with said optimal viable combination produce said matched coating composition that when applied as a matched coating visually matches with the appearance of said target coating.

12. The device of claim 11 further comprising means for configuring computer readable program code devices to cause said computer to display on a screen of a monitor of said device said optimal viable combination.

13. The device of claim 11 further comprising:

(a) means for configuring computer readable program code devices to cause said computer to generate a signal in accordance with said optimal viable combination to dispense said components for making a desired amount of said matched coating composition;

(b) a dispenser for dispensing said components in a container, said dispenser being in communication with said computer;

(c) means for configuring computer readable program code devices to cause said computer to generate a signal upon completion of making said desired amount of said matched coating composition; and

(d) means for configuring computer readable program code devices to cause said computer to generate a signal to said dispenser to stop dispensing of said components.

14. The device of claim 13 further comprising a mixer for mixing said components dispensed in said container.

15. The device of claim 11 wherein said device is a transportable device.

18. The device of claim 11 wherein said spectrophotometer is a multi-angle spectrophotometer.

19. The device of claim 11 wherein said spectrophotometer is a sphere geometry spectrophotometer.

20. A method for producing a matched resin for a specified end-use, said method comprising:

(i) measuring reflectances of a target portion of a target substrate at a set of preset wavelengths with a spectrophotometer of a coating characterizing device to plot a target spectral curve of said target portion;

(step by user)

(ii) calculating target color (L,a,b or L,C,h) values of said target portion from said target spectral curve of said target portion;

(part of step to done by user)

(iii) selecting one or more preliminary colorant combinations from a stored list of known colorants in accordance with a combinatorial selection criteria to match with said target color values;

(in device/computer)

(iv) determining concentrations of each said known colorant in each of said preliminary colorant combinations in accordance with color matching criteria to generate one or more intermediate colorant combinations of said known colorants wherein each of said intermediate colorant combinations is optimized for optimal color match with said target color values;

(v) balancing said intermediate colorant combinations to allow for the presence of non-colorant components in said matched coating composition to generate one or more viable combinations of said known colorants, wherein each of said viable combinations is optimized in accordance with mixing and regulatory practices developed for said specified end-use; and

(vi) selecting an optimal viable combination from said viable combinations in accordance with an acceptability equation for said specified end-use, said optimal viable combination having an optimal acceptability value for said specified end-use wherein components in said optimal viable combination when mixed produce said matched resin that when formed as a matched substrate visually matches the appearance of said target substrate.

21. The method of claim 20 further comprising:

(a) mixing said components in said optimal viable combination with a resin to produce said matched resin; and

(b) processing said matched resin into said matched substrate.

22. The method of claim 21 wherein said processing step comprises injection molding, blow molding, rotational molding, thermoforming or extruding of said matched resin.

23. A matched resin produced by the method of claim 20.

24. The method of claim 20 wherein said matched substrate is a dashboard or interior door panels of an automobile and said target substrate is automobile upholstery.

25. The method of claim 20 wherein said matched substrate is automobile bumper guard and said target substrate is autobody.