CA1243141A

CA1243141A - Process for matching color of paint to a colored surface

Info

Publication number: CA1243141A
Application number: CA000491384A
Authority: CA
Inventors: Renee J. Kelly
Original assignee: EI Du Pont de Nemours and Co
Current assignee: EIDP Inc
Priority date: 1984-09-27
Filing date: 1985-09-24
Publication date: 1988-10-11
Also published as: US4692481A; EP0178096A3; JPH0571061B2; JPS6185481A; DE3576514D1; EP0178096A2; ES547337A0; EP0178096B1; BR8504680A; ES8702471A1; EP0178096B2

Abstract

TITLE
Improved Process For Matching Color Of Paint To A Colored Surface ABSTRACT
An improved process for matching the color characteristics of a paint containing film forming binder, a liquid carrier, colored pigments and flake pigments to the color characteristics of a surface layer that contains flake pigments; the improvement comprises the following:
adding to the paint a dispersion comprising a liquid carrier, a dispersing agent and transparent or semitransparent extender pigments or rigid or semirigid organic particles, particularly preferred are, hollow glass spheres, in an amount sufficient to match the color characteristics of the surface layer.

Description

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TITLE
Improved ~rocess For Matching Color Of Paint To A Colored Surface BACKGROW D OF THE INVENTION
This invention is related to color ma~ching a paint to a colored surface and in particular to an improved process for matching a paint containing flake pigments to a painted surface containing flake pigment6.
Automobiles and trucks are painted with a wide variety of paint~ such as acrylic or nitrocellulo6e lacquers, acrylic, polyurethane, polyester or alkyd enamels and the like. A good color match to the above original paint~ on repair or refinishing of these paints ha6 been difficult to obtain in some cases. In particular, some paints that contain metallic flake pigmen~s are very difficult to color match ~ince the flake orient~
itself to the surface of the painted substrate 2Q differently with each paint and unle6~ the paint u~ed for refinishing or to make a repair allows the metallic flake pigments to orient in the 6ame manner a6 in the original paint, the color will not match, particularly, when viewed from different angles. The aforementioned problem6 occur on refini6hing of automobile6 and trucks and al60 at a manufacturing plant where repairs are made at the completion of as6embly of the automobile or tru~k. A method i6 required that provides for the addition of a compo6ition which changes and randomizes the orientation of the metallic flake in the paint used for refini~hing or repair.
The improved process of ~his invention provides for the addition of the aforementioned composition to paint6 u6ed for refinishing or repair of automobiles and trucks.

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SUMM~RY OF THE INVENTION
An improved process for matching the color characteristic~ of a paint containing film forming binder, a liquid carrier, colored pigment6 and flake pigment6 to the color characteristic6 of a gurface layer ~hat contains flake pigment6; the improvement compri6e6 the following:
adding to the paint a disper6ion comprising a liquid carrier, a qi6per6ing agent and tran6parent or ~emitransparent extender pigment6 or rigid inert organic particle6 in an amount 6ufficien~ to match the color characteristic6 of the 6urface layer.
DESCRIPTION OF THE INVENTION
Problem6 of matching the color characteristic~ of a repair or refinish paint occur when the finish that i6 being repaired or refini~hed is a cros61inked enamel containing flake pigment6 and the paint used for repair or refini6h i6 a lacquer-like paint. The drying and film 6hrinkage characteri6tic6 of an enamel paint film do not allow flake pigment~ to become completely oriented in parallel to the 6urface of the sub6trate that was painted. The lacquer like repair or refini6h paint does allow for a more complete parallel orientation of the flake pigments to the 6urface. The addition of transparent or 6emitran6parent extender pigments such as gla6s bead6 or rigid inert organic particle6 to the repair or refini6h paint provides for random disorientation of flake pigment6 to the extent neces6ary to match the color characteri6tics of the surface being repainted or repaired.
In a typical procedure for matching the 5 color of a refini6h or a repair paint to the color of ~2~3~

an original finish containing ~lake pigments that is being repaired or repainted, ~he pigmentation of the original finis~ i6 obtained from known paint formulas, from past experience with the particular paint or from a color computer. Appropriate amounts of tintings which are a disper6ion of colored pigments, polymeric dispersants and 601vents and flake pigment disper~ion are added to an unpigmented clear ~olymer 601ution and adjustments are made with tintings to obtain a visual color match. The resulting paint i6 reduced to a spray YisCoSity with appropriate solvent~ and 6prayed onto a metal substrate and dried. A visual color compari60n to the ori~inal finish is made and color value6 at three angles are made with an absolute 6pectrophotometer, 6hown in Lee et al. U.S. 4,412,744 is~ued November 1, l9B3. The flop index also is measured.
Flop index is determined by the following formula K (Ll _ L3)a L2b where Ll i6 the head-on brightne6s value, L2 is the flat angle lightnes6 value, and L3 is the high angle lightne6s value; each of the above values are measured by the aforementioned 6pectrophotometer. K, a and b are constant6.
These color values and the f~op index value~
are compared to color value6 of the original finish and a flop index value of ~he original fini6h. If an acceptable color match can be obtained, the refini6h paint i6 applied. If a color match cannot be obtained, particularly if the flop index value of the original finish is lower than the flop index value of the refinish paint, the following procedure i6 u6ed:

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As abo~e, the pigmentation i~ determined.
Appropriate amounts of tintings, 601vents, flake disper~ion and polymer 601ution are added and then a dispersion compri6ing li~uid carrier, di~per6ing agent and transparent or semitran6parent extender pigment6 or rigid inert organic particle6 are added.
The composition then is reduced to a 6pray vi6c06ity and 6prayed onto the substra~e and dried. Color values, lightnes6 value6 and flop index value are measured and if neces6ary additional tintings and/or di6persion of extender pigments or rigid inert organic particles are added to obtain color value6 and flop index value~ that match the original finish.
The dispersion contain6 about 5 to 35% by weight of a liquid carrier, 10 to 40% by weight of a dispersing re6in or agent and 20 to 60% by weight of extender pigment6 or rigid inert organic particles.
The di6per6ion is prepared by blending the constituent6 together and charging them into a 6and mill or other disper6ing equipment and grinding to form a di6per6ion.
The liquid carrier of the disper6ion can be any of the conventional organic solvents which will keep the dispersing agent, which usually i~ a resin, 25 601uble. Typical 601vent~ that can be u6ed are amyl acetate, butyl acetate, xylene and mixture6 thereof.
Water can be used as a solvent if the paint i6 a water based compo6ition. The di6per6ing agent then used is water ~oluble or water disper6ible.
The di6per6ing agent used in the compo6ition preferably i6 a 601uble resin or can be a typical organic di6persing agent. ~eful re6in6 contain an acrylic segment 6uch as an alkyl methacryla~e like methyl methacrylate, butyl methacrylate, ethyl methacrylate, an alkyl acrylate like butyl acrylate, ~Z~3~

ethyl acrylate, a hydroxyl containing constituent such as a hydroxy alkyl methacryla~e or acrylate like hydroxy ethyl methacrylate, hydroxy propyl methacrylate, hydroxy butyl methacrylate, hydroxy ethyl acrylate, hydroxy propyl acrylate, hydroxy butyl acrylate and the like. Al60, ~he re6in can contain an alkyl amino alkyl methacrylate or acrylate such as diethylamino ethyl methacrylate or t-butyl aminoethyl methacrylate.
The re6in also contain6 a drying oil constituent. Typical drying oil cons~ituent6 that are readily polymerized with the aforementioned acrylic constituent6 are vinyl oxazoline drying oil esters of linseed oil fatty acid6, tall oil fatty acids, tung oil fatty acids and the like.
one preferred re~in contains an alkyl methacrylate, alkyl acrylate, hydroxy alkyl acrylate, alkylamino alkyl acrylate and vinyl oxazoline ester of drying oil fatty acids.
Typical transparent or semitran6parent extendec pigments that are used are coarse and fine barytes, crystalline silica, aluminum 6ilicate, hollow glass sphere~, solid gla66 6phere6 or mixtures of the above. Al60, rigid inert organic particle6 can be used such as polypropylene, polyethylene, polystyrene and the like. When u6ing the6e inert organic particles, 601vent6 which 6well or otherwise attack the particle6 cannot be u6ed. Typically, these tran6parent or 6emitransparent or rigid inert or~anic particles have a particle diameter in the range of about 0.1-50 micron6.
Preferably, hollow glass spheres are u~ed that have a diameter of about 0.1-S0 micron~ and prefeLably about 0.1-20 micron6 and have a specific 3s gravity of about 2-2.5. The6e bead6 have a 3~l4~

relatively low ~pecific gravity and are resi6tant to settling out. Particularly preferred are "Zeeospheresl~ of the type o/s~ o/s~ 0/12, 0~16, 0/20, 0/45, 200, 400, 0/300 and 16/300. These hollow gla66 spheres are sold by Zeelan Indust~ies, Inc. One preferred type is 200 having a mean diameter, by volume, of about 5.8 micron6 and a particle size distribution, by volume, of 90% of the particle6 having 10.8 micron diameter or le6s, 50% of the particles having 4.7 micron diameter or less, 10~ of the particles ha~ing 2.3 micron diameter or les6.
T~pical paints that are used on automobiles and truck6 that are repaired with paints matched by the process of this invention are a~ follows:
crosslinked acrylic enamels, aqueous and nonaqueous crosslinked acrylic dispersion enamels, nitrocellulose lacque~s, acrylic lacquers and dispersion lacquers, alkyd resin enamels, polyester enamels, polyester urethane enamels and the like.
Typical repair or refinish paints used in this invention contain pigment disper~ions or tin~ing in which pigment is di6persed in the aforementioned resin containing an acrylic segment and drying oil constituents. The paints can be one of the following: acrylic lacquers, such as a lacquer having a binder of an acrylic polymer, cellulose acetate butyrate and a plasticizer, preferred acrylic polymers are the aforementioned acrylic polymer containing an acrylic segment and drying oil constituent6 and a blend of this polymer and an iminated polymer; another useful acrylic lacquer has a binder of an acrylic polymer haYing an acrylic segment and drying oil constituent, cellulose acetate butyrate plasticizer, an iminated acrylic polymer, an acrylic polymer of an alkyl methacrylate and an alkyl ~243~

acrylate and ethylene vinyl acetate copolymer, nitrocellulose lacquers, acrylic alkyd enamels such as an enamel of the aforementioned polymer having an acrylic segment and drying oil constituents blended 5 with an alkyd resin and optionally, a polyisocyanate crosslinking agent can be used therein; acrylic enamels such as an enamel having a binder of a hydroxyl containing acrylic resin and a melamine crosslinking agent, acrylic urethane enamels, alkyd urethane enamels of an alkyd resin and a polyisocyanate, alkyd enamels, acrylic polyester enamels such as an enamel having a binder of an hydroxyl containing crosslinking agent or a polyisocyanAte crosslinking agent and the like.
Clear coat/color coat finishes on automobiles and trucks can be repaired or refinished with the above paints. The color coat or pigmented coat is matched by the process of this invention and then a clear coat of a conventional lacquer or enamel ~0 is applied over the color coat and dried.
Typical acrylic refinish paints that can be used in the process of this invention are shown in Walus et al. U.S. 3~4881307 issued January 6t 1970.
Donatello et al. U.S. 3r553~124 issued January 5~ 1971 25 Willey U.S. 3~711~433 issued January 16~ 1973~ Meyer U.S. 4~168~249 issued September 18~ 1979 and Fry U.S.
4~451~600 issued May 29~ 1984. Typical acrylic alkyd refinish paints that can be used are shown in Miller et al. U.S. 3~585~160 issued June 15~ 1971~ Miller 30 U~S. 3~753~935 issued August 21~ 1983 and Miller U.S.
3~844~993 issued October 29~ 1974. Typical acrylic polyurethane enamels that can be used are shown in Vasta U.S. 3~558~564 issued January 26~ 1971 and Crawley et al. U.S. 4~131~571 issued December 26~ 1978.

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Typical alkyd resin paints ~hat can be u6ed are shown in Miller U.s. 3,78g,037 issued January 29, 1974.
Nitrocellulo6e lacquer6 ~hat can be u6ed contain nitrocellulose resin having a vi6co~ity of about 1/2-6 6econds as the binder. Preferably, a blend of nitrocellulose re6in6 are used. One useful blend contains about 1-20~ by ~eight, based on the weight of the binder, of 5-6 ~econd viscosity nitrocellulose and 5-40% by weight, based on the weight of the binder of 1~2 6econd nitrocellulose.
Optionally, the lacquer can contain about 0.5-15~ by weight, based on the weight of the binder, of e~ter gum and 5-35% by weight of castor oil.
The aforementioned paints contain conventional colored pigment6 and flake pigments.
Typical flake pigment6 are bright aluminum flake, extremely fine aluminum flake, medium particle 6ize aluminum flake, bright medium coaEse aluminum flake and the like, micaflake coated with titanium dioxide pigment also known a6 pearl pigment6. Con~entional pigment6 that are used are titanium dioxide, carbon black, mono azo red toner, red iron oxide, quinacridone maroon, tran6parent red oxide, dioxazine carbazole ~iolet, iron blue, indanthrone blue, chrome titanate, titanium yellow, mono azo permanent orange, ferrite yellow, mono azo benzimidazolone yellow, transparent yellow oxide, isoindoline yellow, tetrachloroisoindoline yellow, anthanthrone orange, lead chromate yellow, phthalocyanine green, quinacridone red, perylene maroon, quinacridone violet, pre-darkened chrome yellow, thio-indigo red, tran6parent red oxide chip, molybdate orange, molybdate orange red, and the like.
The process of thi6 in~ention can be u6ed to prepare paints at a paint manufacturing plant that 3~

will match known colors of paint6 currently in u6e on automobiles and truck6. Thi6 i6 known in the paint trade as a ~Factory Package~. Factory Package paints can be made under controlled proces~ condition6 and matched to known color6 currently in use. The addition of tran6parent or 6emitransparent pigment6 as discus6ed above make it pos6ible to obtain color matches to known color6.
The proce6s of this invention al60 can be used to style paints. Tran6parent or 6emitran6parent extender pigments such a6 hollow gla~6 bead6 are added to a paint containing flake pigments 6uch as aluminum flake or the above pearl pigment6 in an amount fiufficient to obtain the de6ired glamour for a finish of the paint.
Another a~pect of thi6 invention iB to add colored pigment disper6ion6 and flake di6per6ion to a disper6ion containing the aforementioned extender pigments in 6ufficient amount6 to match the color characteristic6 of a 6urface that i~ being painted.
The following example6 illu6trate the in~ention. All parts and percentage6 are on a weight ba6i6 unle6s indicated otherwi6e.

T~e following aluminum tinting and polymer 601ution6 were prepared and blended together to form an aluminum premix:

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Parts by Aluminum Tintin~ Weight Solvent blend (5% amyl 12.3 acetate, 23.75% butyl acetate and 71.25~ xylene) Thickener solution (3% 9OO
ethylene glycol, 67% xylene, 10~ ammonium bentone, 20~ Antiterra* u wetting agent which is a high molecular weight salt of polycar-boxylic acid) Acrylic Resin Dispersion 46.7 (60% solids of an acrylic vinyl oxazoline ester polymer described in Example 1 of Miller V.S. Patent 3,844,993) Aluminum Flake Paste (70% solids 32.0 coarse aluminum flake in mineral spirits) Total 100.0 The above constituents were thoroughly blended together to form the aluminum tinting.

* denotes trade mark ~t `~ ~2~3~

Parts by Polymer Solution A Weight Butyl acetate 13.79 5 Ethylene glycol monoethyl ether acetate16.94 Xylene 13.61 Cellulose acetate butyrate 3.81 (20 second viscosity) Iminated acrylic polymer 9.52 solution (40~ polymer solids in solvent of an acrylic polymer containing carboxylic acid groups reacted with propyleneimine) E/VA Dispersion (6% solids 42.33 dispersion in blend of xylene/butyl acetate of ethylene/vinyl acetate copolymer) Total 100.00 The above constituents were thoroughly blended together to form a polymer solution.
Parts by Polymer Solution B Weight Butyl acetate 15.87 Ethylene glycol monoethyl ether acetate19.50 Xylene 15.67 Cellulose acetate butyrate 3.29 (20 second viscosity) Butyl benzyl phthalate 2.64 30 Iminated acrylate polymer 10.71 solution (described above) Acrylic polymer solution (40~ 4.88 solids of a polymer of 85%
methyl methacrylate and 15 butyl acrylate in organic solvent) E/VA Dispersion(described above) 27.44 Total 11 100.00 , .
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~Z~3~1 The above con6tituents were thoroughly blended together to form a polymer ~olution.
An aluminum premix was prepared by blending the following constituents:
Part6 by Weiaht Polymer solution A 27B . 42 (prepared above) Polymer solution ~ 177.~2 (prepared above) Aluminum Tinting (prepared above) 136.36 Total 592.60 ~n aluminum paint was prepared by adding 12.78 parts by weight of the above acrylic resin dispersion used to make the aluminum tinting to 592.6 parts of aluminum premix and thoroughly mixing the acrylic resin dispersion and premix.
The re~ulting paint had an aluminum pigment volume concentration of 10.9 and an aluminum/binder ratio of about 30/100.
The above paint was reduced to a s~ray vi6cosity with conventional thinner 601vent6 and ~prayed onto a primed 6teel panel. A clear composition of an acrylic urethane polymer was then 6prayed over the aluminum paint on the panel and dried at ambient temperature for about B hours.
Readings were taken on the panel with an absolute colorimeter described in ~.S. Patent 4,412,744 i6sued on November 1, 1983 to Lee and Reilly at three different angles, i.e., near 6pecular, flat and high, and are 6hown respectively a6 Ll, L2 and L3 on the Table. Ll i6 al60 known a~ head on brightne66, L2 as flat angle lightness and L3 a6 high angle 3~

lightness. The Flop Index was al~o calculated. The aluminum paint prepared above which was without extender pigments is the control to which paint6 containing extender pigments were compared.
A conventional technique for adjusting the Flop Index and lightness of a paint containing flake is to add a dispersion of titanium dioxide pigment.
In many cases, titanium dioxide pigment mask6 the ap~earance of the aluminum fla~e at the high angle lightness, L3, and produces a ring like effect which i6 known as a "bulls eye effect~ which i6 an unacceptable repair for a fini~h. The following dispersions 2-13 were added to the above aluminum premix at the same pigment volume concentration as the titanium dioxide pigment wa6 added. The lightness values and Flop Index Values were measured and are shown in the Table and can be compared to the values obtained with titanium dioxide pigment.
No. 1 Titanium Dioxide Piqment DisPersion Part~ by White Piqment Disper~ion Weiaht Acrylic Resin Disper6ion 28.B8 (described above) organic 601Yent 12.73 Titanium dioxide pigment (Particle 6ize up to 3.2 microns and an effective diameter of 0.2 microns) 56.3~
Thickener solution 2.00 (described above) Total 100.00 The above constituent6 are char~ed into a 6and mill and ground to form a uniform di6per~ion.
The following constituent~ are mixed together to form a white tinting:

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Part6 by White Tintina Weiqh~
Whit~ Pigment Disper~ion (prepared above) 89.00 Acrylic Resin Dispersion 9.45 (de6cribed above) Organic ~olven~ 1.55 Total lOo.OO
~ 36.04 parts by weight of the above white tinting are added to 592.6 parts by weight of the aluminum premix prepared abo~e to provide a titanium dioxide pigment volume concentration of 4.5 and an aluminumtbinder weight ratio of 30/100. The resulting compo6ition wa~ reduced to a 6pray vi6c06ity and 6prayed onto a primed 6teel panel. A
clear compo6ition of an acrylic urethane wa6 6prayed over the above applied compo6ition and dried at ambient temperature6 a6 above and color mea~uremen~s were made and are recorded in the Table. Versu6 ~he control, the measurements show a decrease in head on brightnes6, Ll, an increa6e in flat angle lightnes6, L2, and a large increa6e in high angle lightne66 L3 and a decrea6e in Flop ~ndex. The6e data show that by using titanium dioxide pigment, a large increa6e in high angle lightne66, L3, i6 obtained and in general a good color match u~ing titanium dioxide pigment cannot be expected.
Part6 by No. 2 Coar6e BarYte6 Di6PersionWeiaht 30 Acrylic Re6in Di6per6ion 345.1 tdeBcribed above) Organic 601~ent 103.6 Baryte6 extender piyment (coar6e particle 6ize up to 80 micron6 and having an effective diameter of 8 micron6) 1251.3 Total 1700.0 ~Z~3~

The above con6tituents were charged into a 6and mill and ground to form a ~isper6ion.
28.18 parts by weight of the above barytes dispersion and 7.05 part6 by weight of the acrylic resin dispersion, described above, were added to S92.6 parts by weight of the aluminum premix prepared above to provide a baryte6 pigment volume concentration of 4.5 and an aluminum/binder weight ratio of 30/100. The resulting composition was reduced to a ~pray vi6cosity and 6prayed onto a primed steel panel. A clear composition of an acrylic urethane wa6 sprayed over the applied composition and dried at ambient tempera~ures as above and color measurements were made and are recorded in the Table. The measurement6 in compari on to the control ~how a decrea6e in head on brightne6s, Ll, an increa6e in flat angle lightne66l L2, and an increase in high angle lightnes6, L3, but not as great as with titanium dioxide and a decrea6e in the Flop Index. The above data, in particular the high angle lightnes6 data, indicate6 that a better color match can be made using barytes dispersion in compari60n to a titanium dioxide pigment dispersion.
No. 3 Low Micron Baryte6 DisPersion The di6per6ion i~ prepared the 6ame a6 above coarse baryte6 disper6ion except low micron barytes extender pigment having a weight average particle 6ize of 0.3 to 30 microns having an effective diameter of 6 microns was u~ed for the coar~e barytes extender pigment.
~ 6 above, the low micron barytes disper6ion was added in the same amount to the acrylic re~in disper6ion and to the aluminum premix prepared above and the resulting composition was reduced to a 6pray ~Z~3~

visc06ity and sprayed onto a 6teel panel. A clear composi~ion of an acrylic urethane was sprayed over the applied composition and dried at ambient temperatures as above and color mea6urement6 were made and are recorded in the Table. The re6ult6 are 6imilar to those of the above aluminum paint containing coar~e baryte~ extender pigment but the low micron baryte~ dispersion did not move the Ll, L2, L3 and Flop Index ~alue6 as far as the coarse lo barytes.
Par~s by No. 4 Aluminum Silicate Di6Per6ion Weiqht Acrylic Re6in Di6per6ion 314.8 (de6cribed above) 15 Organic 601vent 159.8 Aluminum 6ilicate extender 660.4 pigment (particle 6ize up to 20 micron6 and having an effective diameter of 3 mi Cl on6) Total 1135.0 The above con~tituent6 were charged into a sand mill and ground to form a disper6ion.
20.63 part6 by weight of the above aluminum 6ilicate di6per6ion and 7.06 part6 by weight of the acrylic resin di6per6ion, de6cribed above were added to 592.6 part6 by weight of the aluminum premix prepared above to provide an aluminum 6ilicate pigment volume concentration of 4.5 and an aluminum/binder weight ratio of 30/100. The resulting compo6ition was reduced to a ~pray vi6c06ity and 6prayed onto a primed 6teel panel.
clear compo6ition of an acrylic urethane wa~ sprayed over the applied compo6ition and dried at ambient temperatures a6 above and color mea~urement6 were 3~

made and are recorded in the Table. T~e mea~urements in compari~on to the control show a sligh~ decrease in ~ead on brightnes6, Ll, only a slight increa~e in flat angle lightnes6, L2, and a 61ight increa6e in high angle lightness, L3. The Flop Index decreased only slightly. The above data i~dica~e6 that only a slight change can be obtained for Ll, L2 and L3 values using aluminum silicate due ~o its ~mall particle size.
Part6 by No. S Glas6 Bead DisPer6ion ~eiaht Acrylic Re6in Di6persion 28.88 (described above) Organic 601vent 12.73 15 Thickener solution (de~scribed above) 2.00 Zeeospheres* 0/5 Hollow Glass Beads 56.39 (having a diameter of 0.1-5 micron~ and an average, by weigh~, diameter of 2.0 microns and a 6pecific gravity of 2.4) 100.00 The above constituents were charged into a sand mill and ground to form a disper6ion.
19.79 part6 by weight of the above gla6s bead di6per6ion and 7.0 part6 by weight of the acrylic resin dispersion were added to 592.6 part~ by weight of the aluminum premix prepared above to provide a glas6 bead pigment volume concentration of 4.5 and an aluminum/binder weight ratio of 30/100.
The resulting composition wa6 reduced to a 6pray vi6c06ity and 6prayed onto a primed steel panel. A
clear compo6ition of an acrylic urethane wa6 6prayed over the applied compo6ition and dried at ambient temperature6 as above and color mea6uremen~ were made and are recorded in the Table. The mea6urements in compari60n to the control ~howed a decrease in * denotes trade mark 3~

head on brightness, Ll, an increase in ~lat angle lightness, L2, and a 61ight increa6e in high angle lightness, L3 and a decrea6e in Flop Index. The above data, in particular the high angle lightness da~a, indicates that a better color match could be obtained using a glass bead dispersion in comparison to a titanium dioxide pigment dispersion.
Seven additional gla6s bead di6persions were prepared using the above cons~i~uents to form the disper6ion, except the following gla6s beads were used in place of the "Zeeosphele6" 0/5 ~lollow Glass Beads:
No. 6 ``ZeeosPhere6ll 0/8 Diameter 0.1-8 microns, Weight Average Diameter 3 micron6 Sp. Gr. 2.3 No. 7 "Zeeo6pheres" 0/12 Diameter 0.1-12 micron~, Weight Average Diameter micron6 Sp. Gr. 2.2 No. B ''ZeeosPhere6ll-o/l6 Diameter 0.1-16 micron6, Weight Average Diameter 6 micron6 Sp. Gr. 2.1 No. 9 "ZeeosPheres" 0/20 Diameter 0.1-20 mic~on6, Weigh~
Average Diameter 8 microns Sp. Gr. 2.0 No. 10 "Zeeospheres" 0~45 Diameter 0.1-45 microns, Weight Average Diameter 12 micron~
Sp. Gr. 2.0 No. 11 ~Zeeos~heres~ 0/300 Diame~er 0.1-300 microns, ~eight A~erage Dia~eter 16 microns Sp. Gr. 2.0 No. 12 ''ZeeosPheresll 16/300 Diameter 16-300 microns, Weight Average Diameter 3B
microns ~p. Gr. 2.0 10Each of the above di6persion6 were formulated into a paint using the 6ame con6tituents as used to form aforementioned aluminum paint except one of the above glass bead dispersions were : substituted for the No. 5 Gla66 Bead di~per6ion. In each case, the re~ulting composition was reduced to a spray viscosity and 6prayed onto a primed steel panel and a clear composition of an acrylic urethane was sprayed oYer the applied composition and dried at ambient temperature6 and color mea6urements were made and recorded in the Table. In general, the mea6urement6 in compari60n to the control had decreased head-on brigh~ne6s, Ll, an increa6e in flat angle lightnes6, L2, and an increa6e in high angle lightne6s, L3. Flop Index and lightne66 values showed that as the glas6 bead 6izes increase, ~1 values decrease, L2 values increa6e, L3 value6 increase and Flop Index Value6 decrease. In general, the high angle lightne6s data indicate~ that a better color match can be obtained by u6ing glass bead disper6ion6 than titanium dioxide pigment disper6ion6.

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Part6 by No. 13 Cr~6talline Silica Di6Per6ion Weiqht Acrylic Re6in Disper6ion 10.94 (described abo~e) 5 Organic solvent blend 6.60 Crystalline Silica (particle 22.98 size of up to 120 micron~
having a density of

2.65g/cm2 and an effective diameter of 10 micron6) Total ~0.52 The above constituent6 were charged into a 6and mill and ground to form a di6per6ion.
21.95 parts of the above 6ilica di~per6ion and 6.85 part6 by weight of the acrylic re6in di6per6ion were added to 592.6 part6 by weight of the aluminu~ premix prepared above to provide a 6ilica pigment volume concentration of ~.5 and an aluminum to binder content weigh~ ratio of 30tlOO. A clear composition of an acrylic urethane was 6prayed over the applied composition and dried at ambient temperature6 a6 above and color measurements were made and are recorded in the Table. The mea~urement6 in compari~on to the control 6howed a decrease in head on brightne66, Ll, an increase in flat angle lightness, L2, an inCrease in high angle lightne~6, L3 and a decrea6e in the Flop ~ndex. The above data indicates that a better color match can be obtained with a silica di6per6ion than can be obtained with a titanium dioxide pigment di6per6ion.

TABLE

Ab601u~e Colorimeter Flop Paint6 Piqment Readina6 Index Ll L2 L3 Control ~one 140.42 56.05 34.11 14.98 1 Titanium 128.41 59.49 43.58 11.08 Dioxide 2 Coarse 12~.26 66.23 38.36 10.24 Barytes

3 Low Micron 133.5B 60.69 35.75 12.76 Barytes

4 Aluminum 138.34 56.99 35.22 14.27 Silicate Zeeo6phere 134.39 59.69 34.97 13.17 0~5 6 Zeeo~phere 134.52 59.72 35.16 13.16 7 Zeeo6phere 131.84 60.75 35.82 12.48 8 Zeeo6phere 133.41 60.81 35.62 12.73 9 Zeeo6phere 130.74 62.40 36.16 12.00 10 Zeeo6phere 129.66 62.93 36.55 11.70 11 Zeeo6phere 127.37 63.76 37.94 11.07 12 Zeeosphere 125.92 63.93 38.23 lO.B0 13 Crystalline 124.73 65.38 38.71 10.37 Silica ~ 2~J 3~1 ~MPLE 2 A color match to a 6ilver metallic enamel was prepared by conventional techniques.
The followin~ di6persions fir6t were prepared:
Parts by Medium Coar6e Aluminum Flake Di6persion Weiaht Organic solvent blend 13.60 Thickener 601ution (described in Example 1~ 4.50 Aluminum flake paste 31.50 (60% solid6 Coarse aluminum flake in mineral 6piri~s) Acrylic resin di6persion 50.40 (described in Example 1) Total 100.00 The above constituent6 are charged into a mixing ve6sel and thoroughly blended to form a di6persion.
PaLts by 20 Carbon Black DisPer6ion Weiqht Acrylic resin di6persion 55.65 (de6cribed in Example 1) Organic 601vent blend 33.35 25 Peptized carbon black lake pigment 11.00 Total 100.00 The above con~tituents are charged into a mill and ground with steel media to form a di6per~ion.

~ Z~3~

Part~ by Carbon Black Tintinq Weiqht Acrylic re6in di6per~ion S (described in Example 1) 80.45 Organic solvent blend 15.21 Carbon black disper6ion 4.34 Total 100.00 The above con6tituents were blended together.
The following paint wa6 formulated u~ing conventional teshniques in an attempt to match the color of the ~ilver metallic enamel.
Parts by Wei~ht Medium Coar6e Aluminum 7.56 Flake Di6per6ion (prepared above) Aluminum Tinting (prepared in 7.56 Example 1) White Tinting (8.90 partE by weight 3.51 of a white pigment di6per6ion prepared in Example 1, 78.33 part6 by weight of an acrylic re6in di6per6ion de~cribed in Example 1, and 12.77 part6 by weight of a ~olvent blend) Carbon Black Tinting 0.75 (prepared above) Polymer Solution A 26.73 (de6cribed in Example 1) Polymer Solution B 53.89 ~described in Example 1) Total 100.00 ~3~
2~
The above con6tituent~ were thoroughly blended together and reduced to a 6pray vi6c06ity and 6prayed onto a primed 6teel panel. A clear compo6i-tion of an acrylic urethane wa~ 6prayed oYer the applied composition and dried at ambient temperature6 and color measurement~ were made a6 in Example 1 and recorded and a curve drawn on ~he graph of Fig. 1.
Fig. 1. also ha6 a curve of the values for the original 6ilver metallic enamel being color matched.
As 6hown on Fig. 1, an exact color match was no~
obtained. To obtain an acceptable color match the two curve~ fihould coincide.
The Flop Index Value was 10.9 for the above compo~ition and for the original 6ilver metallic enamel wa6 7.8.
A 6econd paint wa6 formulated u6ing the technology of thi6 invention.
The following di6per6ion6 fir6t were prepared:
Partz by Tran~parent Yellow Oxide Di6~er6ion Weiqht Acrylic re6in di6per~ion 62.99 ~described in Example 1) Organic Solvent Blend 12.41 25 Tran6iron Oxide Yellow Pigment24.60 Total 100.00 The above con6tituen~6 are charged into a media mill and thoroughly ground to form a di6per6ion.
Par~6 by Yellow Tintin~ Wei~ht Acrylic Re6in Di6per6ion 6.72 (de6cribed in Example 1) Tran6parent Yellow Oxide 85.Z8 (prepared above) Organic Solvent Blend 8.00 Total 100.00 ~Z~3~
The above con6eituen~s were thoroughly blended together to form the ~inting.
Part6 by Mona~tral Blue Di6per~ion ~eiqht Acrylic Re6in Di~per6ion 33.08 (prepared above) organic Solvent 51.92 Monastral* Blue Pigment lS.OO
Total 100.00 The above con~tituen~6 were charged into a media mill and ground to form a di6per6ion.

Part6 by : 15 Blue Tintinq Weiqht Mona6tral Blue Di~per6ion 70.78 (prepared above) Acrylic Re6in Di6per6ion 28.72 (prepared above)-20 Organic Solvent 0.50 Total loO.OO
The above con6tituent6 were thoroughly blended together to form the tinting.
Medium Particle Size Part6 by 25 Aluminum Flake Di6percion ~eiqht organic 601vent 19.80 Thickener 601ution (de6cribed in Example 1) 2.00 Acrylic Re6in Di6per6ion (de6cribed in ~0 Example 1) 46.20 ~edium particle 6ize aluminum flake (65~ 601id6 in mineral 6pirits)32.00 Total 100.00 The above con6tituen~6 are thoroughly mixed together to form a di~per6ion.
* denotes trade mark ~ Z43~

The 6econd paint wa~ prepared by blending together the following con6tituents:
Part~ by Weiqht

5 Carbon black tinting 6.90 ~prepared above) Medium Coar~e Aluminum 6.28 Flake Di6per6ion(prepared above) ~edium Particle Size Aluminum Fla~e Di6per6ion (prepared above~ 4.71 White Tinting(de~cribed above) 1.88 Yellow Tinting (prepared above) 0.08 Blue Tinting (prepared above) 0.02 15 No. 9 Glass Bead Dispersion 5.89 (prepared in Example 1) Polymer Solution A (de6cribed in Example 1) 31.B6 Polymer Solution B (described in Example 1) 42.38 Total 100.00 The above con6tituent6 were thoroughly blended together and reduced to a 6pray visco6ity and 6prayed onto a primed 6teel panel. A clear compo6ition of an acrylic urethane wa~ 6prayed over the applied composition and dried at ambient temperature6 and color measurement6 were made a6 in Example 1 and recorded on the graph of Fig. 1. As the graph 6how6, an almost exact color match wa6 obtained with the 6econd paint. Both curve6 almo6t are 6uperimposed.
Flop Index Value wa6 7.9 in compari~on to the Silver Metallic Enamel which was 7.8.

Claims

1. An improved process for matching the color characteristics of a paint containing film forming binder, a liquid carrier, colored pigments and flake pigments to the color characteristics of a surface layer that contains flake pigments; wherein the improvement comprises adding to the paint a dispersion comprising a liquid carrier, a dispersing agent and transparent or semitransparent extender pigment or rigid inert organic particles in an amount sufficient to match the color characteristics of the surface layer.

2. The process of claim 1 in which the flake pigments are metallic flake pigments.

3. The process of claim 2 in which the metallic flake pigments are aluminum flake.

4. The process of claim 1 in which the extender pigments are selected from the group consisting of barytes, crystalline silica, aluminum silicate, hollow glass spheres, solid glass spheres or mixtures thereof.

5. The process of claim 1 containing rigid inert organic particles.

6. The process of claim 5 in which the rigid inert organic particles are selected from the group consisting of polypropylene, polyethylene and polystyrene particles.

7. The process of claim 4 in which the extender pigments are hollow glass spheres having a diameter of 0.1-50 microns.

8. The process of claim 4 in which the dispersing agent comprises an acrylic resin.

9. The process of claim 8 in which the liquid carrier is an organic solvent and the dispersing agent comprises an acrylic vinyl oxazoline ester polymer.

10. The process of claim 9 in which the acrylic vinyl oxazoline ester polymer consists essentially of an alkyl methacrylate, alkyl acrylate, hydroxy alkyl acrylate or methacrylate, alkylamino alkyl acrylate and vinyl oxazoline ester of drying oil fatty acids.

11. The process of claim 1 in which the flake pigments are aluminum flake, the extender pigments are hollow glass spheres having a diameter of 0.1-50 microns, the liquid carrier is an organic solvent and the dispersing agent comprises an acrylic vinyl oxazoline ester polymer consisting of an alkyl methacrylate, an alkyl acrylate, hydroxy alkyl acrylate or methacrylate, an alkyl amino alkyl acrylate and vinyl oxazoline ester of drying oil fatty acids.

12. The process of claim 1 in which color values at three angles are measured with an absolute spectrophotometer and the flop index value are determined for the surface layer and the same values for the paint are measured and necessary adjustments made by adding the dispersion to the paint to match the values of the surface layer.

13. The process of claim 1 in which the binder of the paint comprises a mixture of an acrylic polymer containing reactive hydroxyl groups and a polyisocyanate.

14. The process of claim 1 in which the binder of the paint comprises an alkyd resin.

15. The process of claim 1 in which the binder of the paint comprises a blend of an alkyd resin and a polyisocyanate.

16. The process of claim 1 in which the binder of the paint comprises nitrocellulose having a viscosity of about 1/2-6 seconds.

17. The process of claim 1 in which the binder of the paint comprises an acrylic polymer, cellulose acetate butyrate and a plasticizer.

18. The process of claim 17 in which the acrylic polymer comprises a polymer containing an acrylic segment and drying oil constituents and optionally contains an iminated acrylic polymer.

19. The process of claim 1 in which the binder of the paint comprises an acrylic polymer having acrylic segments and drying oil constituents, cellulose acetate butyrate, plasticizer, an iminated acrylic polymer, an acrylic polymer of an alkyl methacrylate and an alkyl acrylate and ethylene vinyl acetate copolymer.

20. The process of claim 1 in which the binder of the paint comprises an acrylic vinyl oxazoline ester polymer and an alkyd resin.

21. The process of claim 20 in which the binder of the paint contains a polyisocyanate crosslinking agent.

22. The process of claim 1 in which the binder of the paint comprises an acrylic resin, a urethane resin and a melamine crosslinking agent or a polyisocyanate crosslinking agent.

23. The process of claim 1 in which the paint comprises an acrylic polymer containing reactive hydroxyl groups and a melamine crosslinking agent.

24. The process of claim 1 in which the paint comprises an acrylic polymer containing reactive hydroxyl groups, a polyester resin and a melamine crosslinking agent or a polyisocyanate crosslinking agent.

25. The process of claim 1 in which the surface layer comprises a color coat containing flake pigments and a clear coat layer in adherence to the color coat.

26. The process of claim 1 in which flake particles in the paint upon drying orient differently from the flake particles in the surface layer caused by shrinkage characteristics of the paint thereby requiring the addition of extender pigments or rigid inert organic particles thereby altering the orientation of the particles in the paint sufficiently to match the color characteristics of the surface layer being painted.

27. A coating composition comprising an organic solvent, a film forming binder, colored pigments, flake pigments, dispersing agent of an acrylic vinyl oxazoline ester polymer and extender pigments consisting of hollow glass spheres having a diameter of 0.1-50 microns.

28. A substrate comprising a layer containing a flake pigmented coating coated with a dried coalesced layer of the composition of claim 27.