JP2001131486A - Thermochromic coating composition, method for forming thermochromic designed coating film and coated matter - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a thermochromic coating composition having design properties high enough to form a pattern harmonious with a highly designed pattern such as a metallic coating or the like and excellent in weather resistance. SOLUTION: A thermochromic coating composition comprising a silica flake pigment coated with a thermoreversible metal oxide and a vehicle is applied on a heatable base material to give a coating film thereby forming a pattern exhibiting colors reversibly changing depending on whether it is heated or not. A coated matter having a pattern formed thereon by the above method for forming a coating film exhibits excellent multicolorinterferential thermochromism of high saturation and high brilliance and has good weather resistance.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a thermoreversible metal oxide-coated silica flake pigment which is suitable for coating on the outer surfaces of vehicles such as automobiles and motorcycles, outer surfaces of containers, coil coatings, and surfaces of home electric appliances. The present invention relates to a thermochromic coating composition containing the same, a method for forming a thermochromic design coating film using the coating composition, and a coated article obtained by this method.

[0002]

2. Description of the Related Art An invention in which a pattern is drawn on a vehicle outer panel by using a temperature-indicating paint and changes in design such as colors and patterns are caused by utilizing air temperature, vehicle engine temperature and the like is disclosed in, for example, Japanese Patent Application Laid-Open No.
No. 171433. However, for a coating film having a high degree of design such as a metallic coating, such as an automobile outer panel, a sufficient design cannot be obtained with the conventional temperature indicating paint. In addition, inorganic compounds used as conventional thermochromic pigments have a problem of containing mercury, while organic compounds have a problem that they are practically impossible to use for automobile outer panels due to poor weather resistance. Was.

[0003]

SUMMARY OF THE INVENTION Therefore, an object of the present invention is to provide a high design which can form a pattern etc. in harmony with a coating having a high design such as a metallic coating. Another object of the present invention is to provide a thermochromic coating composition having good weather resistance.

[0004]

The thermochromic coating composition of the present invention contains a thermoreversible metal oxide-coated silica flake pigment and a vehicle. By applying the thermochromic coating composition to a heatable substrate and forming a coating film, a patterned coating film having a reversible color when heated or not heated can be formed. Further, the coated product of the present invention, on which a patterned coating film is formed by the above-described coating film forming method, exhibits high chroma, high luminance, excellent thermochromic properties exhibiting multicolor interference, and good weather resistance.

[0005]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below in detail. The feature of the thermochromic coating composition of the present invention is that it contains a metal oxide-coated silica flake pigment having thermoreversibility. This pigment is a pigment having strong multicolor interference, high chroma, high luminance, excellent design, and weather resistance. These are manufactured, for example, as follows. That is, first, a hydrolyzable silicon alkoxide (silicon tetramethoxide, silicon tetraethoxide, etc.) is prepared as a raw material of silica flake, and this is
Cured at room temperature to 80 ° C. for 5 minutes to 48 hours together with a solvent such as isopropyl alcohol and acidic water to form a sol solution. Next, the sol solution is spread on a conveyor-type plastic belt so as to have a uniform thickness. This includes
Any method such as dip, flow, spray, etc. can be used, but the thickness of the produced silica flake is 300 to
It is necessary to control to be within 500 nm. The sol liquid spread on the belt becomes a gel film by passing through a heating furnace, and when heated and dried, loses moisture and shrinks, cracks, and forms silica flakes.

The silica flakes formed by the above procedure are then added to water to form a suspension, mixed with a metal salt solution while maintaining the pH at a constant acidity, to provide a metal oxide coating on the surface. . Examples of this metal salt include TiCl
₄ , FeCl ₂ and FeCl ₃ . Next, the coated silica flake is taken out, dried, and sintered at 700 to 1000 ° C. to obtain a metal oxide-coated silica flake pigment.

The thus obtained metal oxide-coated silica flake pigment is obtained by coating a substrate made of flake silica (silicon dioxide) with a metal oxide different from the metal oxide of the substrate. Substrate thickness is 300-50
0 nm is preferable, and more preferably 400 to 450 nm.
And the major axis is preferably from 5 to 60 μm, more preferably from 10 to 40 μm. Examples of the metal oxide coated here include iron oxide (iron monoxide, diiron trioxide, hematite) and titanium dioxide (anatase type or rutile type). The thickness of the metal oxide coating layer is 50 to 200.
nm, more preferably 60 to 180 nm.

The reason why the metal oxide-coated silica flake pigment exhibits thermoreversible discoloration is considered as follows. That is, the silica flake substrate releases water in the process of heating and drying the gel film, and a large number of pores are formed in the trace.
These pores apply a metal oxide coating on silica flakes,
Even after sintering to form a pigment, it is usually not sealed,
It contains water in the atmosphere. Originally, the reason why the metal oxide-coated silica flake pigment exhibits multicolor interference is that light passes through the surface of the metal oxide coating, the interface between the metal oxide coating and the substrate (both have different refractive indexes), and after passing through the substrate. This is because the light is reflected at a plurality of sites, such as the interface with the metal oxide coating on the back surface, and the light is mixed to form a color. Therefore, when an event occurs that affects the relative refractive index between the substrate and the coating, the interference color changes. That is, the refractive index of the pore changes between the case where water is present in the pores present on the surface of the substrate and the case where water is released due to a rise in temperature to form an air layer. And the interference color changes as a result.

The content of the above metal oxide-coated silica flake pigment in the thermochromic coating composition (solid content of coating 100
The mass ratio of the solid content of the pigment to the parts by mass (PWC) is 0.1.
01-30% is preferred. If the PWC is less than 0.01%, it is difficult to obtain a multicolored patterned coating film. If the PWC is more than 30%, a smooth coating film cannot be obtained, so that various properties required for the thermochromic coating film cannot be obtained. In addition, the storage stability of the paint may be impaired. More preferred PWC is 0.1 to 20% when the color of the thermochromic coating is reduced by lowering the concealing property of the thermochromic coating. When concealment is provided, the content is 0.5 to 30%.

[0010] Other pigments can be used together as long as the effect of the metal oxide-coated silica flakes is not impaired. Examples thereof include brilliant pigments such as aluminum flakes and colored mica, organic pigments such as phthalocyanine-based, indigo-based, and quinacridone-based, inorganic pigments such as redwood, titanium dioxide, and carbon black, and extender pigments such as kaolin, diatomaceous earth, and barium carbonate. Is mentioned.

On the other hand, the vehicle contained in the thermochromic coating composition of the present invention is for dispersing the above metal oxide-coated silica flake pigment, and is composed of a resin for forming a coating film and, if necessary, a crosslinking agent. Be composed.

Examples of the resin for forming a coating film constituting the vehicle include an acrylic resin, a polyester resin, an alkyd resin, a fluororesin, an epoxy resin, a polyurethane resin, a polyether resin, and modified resins thereof.
These can be used alone or in combination of two or more. Among them, preferred are acrylic resins and polyester resins. Further, when the base coating film is obtained from a glitter paint, a carboxyl group-containing polymer and an epoxy group-containing polymer can be exemplified as a film-forming resin that is particularly preferably used from the viewpoint of acid rain resistance.

The carboxyl group-containing polymer is a copolymer of a radical polymerizable monomer containing an acid anhydride group and another copolymerizable monomer, wherein the acid anhydride group is opened to form a half-ester. Are preferred. Examples of the radical polymerizable monomer containing an acid anhydride group include maleic anhydride, itaconic anhydride, citraconic anhydride, phthalic anhydride, tetrahydrophthalic anhydride, hexahydrophthalic anhydride, methyltetrahydrophthalic anhydride, and hymic anhydride. , Trimellitic anhydride, pyromellitic anhydride, succinic anhydride and the like, and these can be used in combination of two or more.

Other copolymerizable monomers include styrenes (styrene, α-methylstyrene, etc.), acrylates (methyl (meth) acrylate, ethyl (meth) acrylate, propyl (meth) acrylate, Butyl (meth) acrylate, n-propyl (meth) acrylate, n-butyl (meth) acrylate, isobutyl (meth) acrylate, 2-ethylhexyl (meth) acrylate, n-octyl (meth) acrylate, (Meta)
N-dodecyl acrylate), (meth) acrylamide and the like. The above “(meth) acryl”
Represents acryl and methacryl.

The content of the above monomer in the carboxyl group-containing polymer is 10 to 40% by mass of a radical polymerizable monomer containing an acid anhydride group, and 90 to 60% by mass of another copolymerizable monomer. Is preferred. More preferably, the radical polymerizable monomer is 15 to 30% by mass, and the other copolymerizable monomer is 85 to 70% by mass.

The copolymerization of a radical polymerizable monomer containing an acid anhydride group with another copolymerizable monomer is carried out by a known method,
For example, it can be performed by a radical polymerization method or the like. The number average molecular weight of the carboxyl group-containing polymer is 500 to 40.
000, and particularly preferably 1,000 to 20,000.

The half esterification is performed after the copolymerization. The half esterifying agent is a low molecular weight alcohol (methanol, ethanol, propanol, butanol, methyl cellosolve, ethyl cellosolve, etc.). The half esterification reaction is carried out at a temperature of room temperature to 120 ° C. in the presence of a catalyst (tertiary amines such as triethylamine and tributylamine).

The epoxy group-containing polymer is composed of 30 to 70% by mass of a radical polymerizable monomer having an epoxy group and 10 to 70% by mass of a radical polymerizable monomer having a hydroxyl group.
A copolymer of 50% by mass and the remaining amount of other radically polymerizable monomers, wherein the epoxy equivalent is 100 to 800;
Preferably from 200 to 600, with a hydroxy equivalent of 200
~ 1200, preferably 400-1000. The epoxy group-containing polymer has 2 to 10, preferably 3 to 8, epoxy groups in the molecule, and has 2 to 1 hydroxyl groups.
It has two, preferably four to ten.

Examples of the radical polymerizable monomer having an epoxy group include glycidyl (meth) acrylate,
3,4-epoxycyclohexanylmethyl methacrylate and the like. The radical polymerizable monomer having a hydroxyl group includes hydroxymethyl (meth) acrylate, hydroxyethyl (meth) acrylate, (meth)
Radical polymerizable monomers having a hydroxyl group such as hydroxypropyl acrylate, hydroxybutyl (meth) acrylate, and N-methylol acrylamine are exemplified. Other radically polymerizable monomers may be the same as those used for the carboxyl group-containing polymer.

The compounding amount of the carboxyl group-containing polymer and the epoxy group-containing polymer is 100: 50 to 1 by mass.
00: 250 is preferred. Each polymer is used at a required viscosity using a diluent.

On the other hand, preferred acrylic resins as the above-mentioned film-forming resins include hydroxymethyl (meth) acrylate, hydroxyethyl (meth) acrylate, and 2-hydroxyethyl (meth) acrylate, which are ring-opened adducts of caprolactone. , Hydroxybutyl (meth) acrylate,
Hydroxyl group-containing (meth) such as N-methylolacrylamide
Acrylic ester monomers, oxirane ring-containing monomers such as glycidyl (meth) acrylate, and ethylenically unsaturated monomers having a carboxyl group such as (meth) acrylic acid, crotonic acid, itaconic acid, fumaric acid, and maleic acid Monomers and methyl (meth) acrylate, ethyl (meth) acrylate, propyl (meth) acrylate, butyl (meth) acrylate, 2-ethylhexyl (meth) acrylate,
It can be obtained by polymerizing at least one kind of alkyl (meth) acrylate such as n-octyl (meth) acrylate and n-dodecyl (meth) acrylate by an ordinary method. Further copolymerizable (meth) acrylonitrile, styrene, (meth) acrylamide, dimethylacrylamide, N, N-dimethylpropylacrylamide, N-butoxymethylacrylamide, styrene, α-methylstyrene, itaconic acid, maleic acid, acetic acid Vinyl and the like may be blended. The number average molecular weight of the acrylic resin is preferably from 1,800 to 100,000, more preferably from 5,000 to 20,000.

The polyester resin is obtained by polycondensing (esterifying) a polyhydric alcohol and a polybasic acid or its anhydride. The number average molecular weight of the polyester resin is preferably from 200 to 10,000, and from 300 to 60.
00 is more preferred.

Examples of the polyhydric alcohol include ethylene glycol, propylene glycol, 1,3-butylene glycol, 1,6-hexanediol, diethylene glycol, dipropylene glycol, neopentyl glycol, triethylene glycol, glycerin, trimethylolethane, Trimethylolpropane, pentaerythrit, dipentaerythrit and the like are preferable, and it is more preferable to use a combination of two or more of these polyhydric alcohols.

Further, as the polybasic acid or its anhydride,
Phthalic acid, phthalic anhydride, isophthalic acid, terephthalic acid, succinic acid, succinic anhydride, adipic acid, azelaic acid, sebacic acid, tetrahydrophthalic anhydride, hexahydrophthalic anhydride, maleic anhydride, fumaric acid, itaconic acid, anhydride Trimellitic acid and the like are preferable, and it is more preferable to use these in combination of two or more.

The coating film forming resin includes a curable type and a lacquer type. Usually, a curable type is used. In the case of a type having curability, heating or heating is performed by mixing and using amino resins such as melamine resins, (block) polyisocyanate compounds, amines, polyamides, and polycarboxylic acids as crosslinking agents. The curing reaction can proceed at room temperature. It is also possible to use a lacquer type coating film forming resin having no curability and a curable type in combination.

Examples of the amino resin include a condensate obtained by reacting one or a mixture of two or more amino compounds such as melamine, urea and benzoguanamine with formaldehyde, and a lower alcohol such as methanol or butanol to the condensate. An alkyl etherified melamine resin that has been reacted is exemplified. The number average molecular weight of such an alkyl etherified melamine resin is preferably from 400 to 2,000.

As the above blocked polyisocyanate compound, hexamethylene diisocyanate (HMDI)
Polyfunctional isocyanates such as aliphatic polyfunctional isocyanates such as isophorone diisocyanate (IPDI) and polyisocyanate compounds such as diphenylmethane-4,4'-diisocyanate (MDI) and hydrogenated MDI. One that is completely blocked.

When the vehicle is of the ultraviolet curing type,
An ultraviolet radical curing type in which an ultraviolet radical polymerization initiator such as an allyl ketone is blended with a known material having an acrylate group, a methacrylate group, an aryl group or the like capable of radical polymerization without solvent or diluted with an organic solvent. Resin composition, UV cationically curable resin prepared by blending an ultraviolet cationic polymerization initiator such as a sulfonium salt with a known material having a cyclic ether group such as an epoxy group and an oxetane group having a cationic polymerization ability, a vinyl ether group and the like. A composition and a mixed resin composition thereof can be used.

When the above-mentioned vehicle contains a crosslinking agent, the ratio of the coating film forming resin to the crosslinking agent is 90 to 50% by mass and the crosslinking agent is 10 to 50% by mass in terms of solid content. Preferably, the coating film forming resin is 85 to 60% by mass, and the crosslinking agent is 15 to 40% by mass. If the amount of the crosslinking agent is less than 10% by mass (the amount of the resin for forming a coating film exceeds 90% by mass), the crosslinking in the coating film is not sufficient. On the other hand, when the cross-linking agent exceeds 50% by mass (the resin for forming a coating film is 50% by mass
), The storage stability of the coating composition is reduced and the curing speed is increased, so that the appearance of the coating film is deteriorated.

In addition, various additives can be added as long as the design properties and weather resistance of the thermochromic coating composition are not impaired. Examples thereof include a polyamide wax which is a lubricant dispersion of an aliphatic amide and a polyethylene wax which is a colloidal dispersion mainly composed of polyethylene oxide, an anti-settling agent, a curing catalyst, an ultraviolet absorber, an antioxidant, a leveling agent, Surface modifiers such as silicone and organic polymers, anti-sagging agents, thickeners, defoamers, crosslinkable polymer particles (microgels)
And the like. These additives are usually added in an amount of 15 parts by weight to 100 parts by weight of the vehicle (based on solid content).
By blending at a ratio of not more than part by mass, the performance of the paint and the coating film can be improved.

The thermochromic coating composition of the present invention is provided in a form in which the above components are usually dissolved or dispersed in a solvent. Any solvent may be used as long as it dissolves or disperses the vehicle, and an organic solvent and / or water is used.
Examples of the organic solvent include those commonly used in the field of coatings, for example, hydrocarbons such as toluene and xylene, ketones such as acetone and methyl ethyl ketone, esters such as ethyl acetate, cellosolve acetate and butyl cellosolve, and alcohols. And the like. However, when the use of an organic solvent is regulated from the viewpoint of environmental protection, it is preferable to use water.
In this case, an appropriate amount of a hydrophilic organic solvent may be contained.
The preferable addition amount of the solvent is 30 to 1 with respect to the film-forming resin.
50% by mass.

In the method of forming a thermochromic design coating film of the present invention, the method is applied directly on a substrate to be coated or on a formed metallic coating film, solid coating film, plating film or the like. It forms a coating film having a reversible color at the time of warming. Therefore, the color of the coating film formed using the same heat-modified coating composition is different between the heated portion and the non-heated portion, and a pattern can be formed due to the difference in coloring. The pattern coating may be formed before or after the clear top coat is applied. The surface temperature of the substrate to be coated is 50 ° C.
As described above, it is necessary to form it preferably at a place where the temperature rises to 70 to 100 ° C. Examples of such places include the roof panel of the automobile outer panel, the bonnet around the built-in engine, the muffler of a motorcycle, the outer surface of a heated beverage can such as a coffee can, and the built-in motor for home appliances. Cover around the part.

Examples of patterns to be formed include characters and graphics related to the product, trademark, company name, advertising text, picture, etc., and letters and graphics related to "heating attention". Since the patterned coating film formed by the thermochromic coating composition of the present invention exhibits strong multicolor interference, it is very conspicuous when heated and cooled on a solid coating film. Further, when formed on a plating film or a metallic coating film, for example, a red interference color changes to a yellow interference color by heating, and a subtle color change with high design quality can be produced.

The substrate to be coated is not particularly limited as long as it can be used under heating. For example, iron, aluminum,
Metals such as copper, tin, chromium, nickel and their alloys are most suitable. Further, the present invention can be applied to inorganic materials such as glass, pottery, cement, and concrete. In addition, polyethylene resin, polypropylene resin,
Ethylene-vinyl acetate copolymer resin, polyamide resin,
It is conceivable to apply patterns on resins such as acrylic resin, vinylidene chloride resin, polycarbonate resin, polyurethane resin, epoxy resin and various plastic materials such as FRP not only for design but also for checking surface temperature. Can be

The method for coating the thermochromic coating composition of the present invention on a substrate to be coated is not particularly limited, but a spray method, a roll coater method, a screen transfer method and the like are preferable. Can be increased. The dry thickness of the patterned coating film is preferably 5 to 50 μm per coat, and if it is less than 5 μm, multicolor interference cannot be sufficiently exhibited, and if it exceeds 50 μm, the appearance of the coating film may be deteriorated. More preferably, it is 10 to 30 μm.

[0036]

Next, the present invention will be described more specifically with reference to examples and comparative examples. In addition, the compounding amount represents a mass part unless there is particular notice.

Examples 1 to 3 and Comparative Example 1 Preparation of Substrate to be Coated A dull steel sheet (length 1000 mm, width 300 mm and thickness 1.5 mm) was treated with a zinc phosphate treating agent ("Surfdyne SD").
2000 ", manufactured by Nippon Paint Co., Ltd., and then cationic electrodeposition paint (" Power Top U-50 ",
Nippon Paint Co., Ltd.) was electrodeposited so that the dry film thickness was 25 μm. Subsequently, it was baked at 160 ° C. for 30 minutes to prepare a substrate to be coated. An intermediate paint ("Olga S-90 Sealer Gray", manufactured by Nippon Paint Co., Ltd.) is applied by air spray coating on the electrodeposition coating film so that the dry film thickness becomes 40 μm.
Baking was performed at 140 ° C. for 30 minutes to form an intermediate coating film.

Formation of Metallic Coating Film The following metallic coating film was formed on the intermediate coating film. That is, an acrylic resin (styrene / methyl methacrylate / ethyl methacrylate / hydroxyethyl methacrylate / methacrylic acid copolymer, number average molecular weight of about 2
000, a hydroxyl value of 45, an acid value of 15, and a solid content of 50% by mass) and a melamine resin ("Uban 20SE", manufactured by Mitsui Chemicals, Inc., solid content of 60% by mass) in a solid content mass ratio of 80:20. To the vehicle obtained by blending, 10% of a metallic pigment (aluminum paste MH-8801, manufactured by Asahi Kasei Kogyo Co., Ltd.) by PWC and a transparent iron oxide coloring pigment (Sicotrans Red L-2715, manufactured by BASF) by PWC. 2
%. Then, an organic solvent (toluene / xylene / ethyl acetate / butyl acetate mass ratio = 70/15)
/ 10/5) with a dissolver to stir and mix so as to have an appropriate coating viscosity to prepare a metallic coating composition. Then, this metallic coating composition was spray-coated so that the dry film thickness became 15 μm. After coating, set for 3 minutes and dry paint to a dry film thickness of 35μm
Paint, set at room temperature for 10 minutes,
Bake at 140 ° C. for 30 minutes.

Formation of Solid Coating Film The metallic coating composition in the formation of the above-mentioned metallic coating film was changed to an alkyd melamine resin-based solid coating material (“Olga G-75 Gray Color”, manufactured by Nippon Paint Co., Ltd.) to a dry film thickness of 30 μm. Spray paint at room temperature
Minutes and baked at 140 ° C. for 30 minutes.

Preparation of thermochromic paint A thermochromic paint composition was prepared in the same manner as the metallic paint except that the metallic pigment of the above metallic paint was replaced with a thermoreversible iron oxide-coated silica flake pigment. .

Formation of Pattern Coating (Example 1) The thermochromic coating composition was spray-coated on the substrate to be coated so that the dry film thickness became 15 μm.
After coating, set for 3 minutes, spray-coated with clear paint (“Super Lac O-130”, manufactured by Nippon Paint Co., Ltd.) so that the dry film thickness becomes 35 μm, set at room temperature for 10 minutes, and set at 140 ° C. for 30 minutes. Bake for a minute. When the coated plate after cooling is heated to room temperature at 90 ° C.,
What was reddish-brown during cooling turned yellow-brown, and when cooled to room temperature, it returned to its original color and was confirmed to be a thermoreversible thermochromic coating. Further, when heating was partially performed, the heated portion turned yellow-brown, and the non-heated portion hardly changed color, confirming the formation of a pattern due to the presence or absence of the color change.
The weather resistance was measured by an accelerated test using a sunshine weatherometer (manufactured by Suga Test Instruments Co., Ltd.), and almost no discoloration was observed after 2,000 hours.

(Example 2) The above-mentioned metallic coating film was partially masked with the thermochromic coating composition to change the letters of the alphabet NP to a dry film thickness of 15 parts.
μm spray coating, set for 3 minutes after coating, clear paint (“Super Rack O-13
0 "(manufactured by Nippon Paint Co., Ltd.) was spray-coated so that the dry film thickness became 35 μm, set at room temperature for 10 minutes, and baked at 140 ° C. for 30 minutes. As in Example 1, it was confirmed that the thermochromic coating film was capable of forming a thermoreversible pattern (NP characters) and that the weather resistance was good.

(Example 3) A part of the solid coating film was masked with the thermochromic coating composition to form an alphabet NP pattern having a dry film thickness of 15 μm.
m, and set for 3 minutes after coating, and then clear paint (“Super Rack O-13”).
0 "(manufactured by Nippon Paint Co., Ltd.) was spray-coated so that the dry film thickness became 35 μm, set at room temperature for 10 minutes, and baked at 140 ° C. for 30 minutes. As in Example 1, it was confirmed that the thermochromic coating film was capable of forming a thermoreversible pattern (NP characters) and that the weather resistance was good.

Comparative Example 1 The thermochromic coating composition of Example 2 was replaced by a thermochromic pigment (an inorganic compound having an AgHgI ₄ structure) in place of the thermoreversible iron oxide-coated silica flake pigment. It was confirmed that the coating film was formed in the same manner as in Example 2 and was a thermo-discolorable coating film capable of forming a thermoreversible pattern (NP characters), but the weather resistance was such that the discoloration was large and insufficient. It could be confirmed.

[0045]

Since the thermochromic coating composition of the present invention contains a heat-reversible metal oxide-coated silica flake pigment, it is applied to a heatable substrate, and when heated, it is not heated. When a coating film having a reversible color at the time of warming is formed, the coloration of the coating film formed using the same heat-modified coating composition differs between the heated portion and the non-heated portion, and the pattern formation due to the difference in color formation Becomes possible. The patterned coating film exhibits excellent thermochromic properties with high chroma and high luminance showing multicolor interference, and also has good weather resistance.

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat ゛ (Reference) C09C 3/06 C09C 3/06 C09D 5/26 C09D 5/26 F-term (Reference) 4D075 CB08 DA06 DB02 DC12 EA02 EC03 4J037 AA18 CA05 CA09 DD05 EE03 EE26 EE28 EE43 FF02 FF22 4J038 CD091 CG141 DB001 DD001 DD121 DF001 DG001 HA446 KA08 KA15 KA20 MA03 MA12 NA01 NA03 NA16 PB04 PB07 PB09 PC02

Claims (3)

[Claims] 1. A thermochromic coating composition comprising a thermoreversible metal oxide-coated silica flake pigment and a vehicle. 2. A thermochromic coating composition according to claim 1, which is applied to a heatable substrate to form a pattern having a reversible color when heated and when not heated. Thermochromic design coating film forming method. 3. A coated product, wherein a patterned coating film is formed by the coating film forming method according to claim 2.