WO2005019358A1

WO2005019358A1 - Coating composition for heat-insulating film formation and method of coating with the same

Info

Publication number: WO2005019358A1
Application number: PCT/JP2004/012332
Authority: WO
Inventors: Makoto Sano; Keiichiro Saikawa; Tetsuo Ogawa; Masami Sugishima; Shinji Tsushima; Yoshiaki Chino; Teppei Oohori
Original assignee: Kansai Paint Co., Ltd.
Priority date: 2003-08-22
Filing date: 2004-08-20
Publication date: 2005-03-03
Also published as: JPWO2005019358A1

Abstract

A coating composition for heat-insulating film formation which comprises (A) a resin ingredient forming a coating film having a refractive index of 1.30 to 1.60 and (B) a white pigment having an average primary-particle diameter of 500 to 2,000 nm and a refractive index of 1.80 to 3.00; and a method of coating with the coating composition.

Description

Specification

Thermal barrier coating forming coating composition and coating method using the same

The present invention relates to a coating composition capable of forming a heat-shielding coating that suppresses an increase in internal temperature of a building or the like, and a coating method using the same. Background technology

It is necessary to control the rise in the internal temperature of the building due to the irradiation of sunlight, etc., because it reduces the cost of air conditioning. In particular, the need for inorganic building materials such as concrete used as building materials for buildings and houses has a high heat storage property and promotes a rise in the temperature inside the building.

On the other hand, oil tanks, grain tanks, and the like have the problem that the temperature difference between the inside and outside of the tank increases due to the irradiation of sunlight, so that volatile components evaporate and the grain deteriorates.

Accordingly, there is a need for the development of a coating composition for forming a thermal barrier coating capable of imparting a sufficient thermal barrier effect to the outer wall and roof of a building, the outer surface of a tank, and the like.

Conventionally, it has been known that a white coating film formed from a coating composition containing a titanium dioxide pigment having an average particle size of about 200 to 300 nm has excellent underlayer concealing properties and exhibits a certain degree of heat shielding effect. ing. However, its heat shielding effect was not satisfactory. Further, when a coloring pigment is further added to the above-mentioned coating composition and the coating film is colored deeply, the heat-shielding effect is significantly reduced.

JP-A-2-185572 discloses a solar heat-shielding coating composition containing a resin component having excellent weather resistance, a solar heat-shielding pigment such as zirconium oxide, and a composite oxide-based coloring pigment. According to the composition, a coating film having heat shielding properties and excellent weather resistance can be formed, but in the case of a dark-colored coating film, the heat shielding effect may not be observed.

Japanese Patent Application Laid-Open No. Hei 11-113-1977 discloses a heat-shielding paint containing hollow particles made of ceramic (ceramic table) and a structure-retaining agent for densely stacking ceramic bubbles. According to this paint, it is possible to obtain a coating film having a high heat shielding effect with a single layer. However, since the particle diameter of the ceramic bubbles is as large as 5 to 150 / m, there is a problem that the gloss of the coating film is reduced. Disclosure of the invention

SUMMARY OF THE INVENTION An object of the present invention is to provide a coating composition for forming a heat-shielding film and a coating method using the same, which can form a coating film having an excellent heat-shielding effect and having sufficient underlayer concealing property and gloss.

Other objects and features of the present invention will become apparent from the following description. The present inventor has made intensive studies to achieve the above object. As a result, a white pigment having an average primary particle diameter in the range of 500 to 2,000 nm and a refractive index in the range of 1.8 to 3.0 is converted to infrared rays as heat rays. According to the coating composition in which the white pigment is mixed with a resin component forming a film having a refractive index of 1.3 to 1.6, the heat-shielding effect is excellent. Further, it has been found that a coating film having a sufficient underlayer concealing property and gloss can be formed. The present invention has been completed based on such findings.

The present invention provides the following coating composition for forming a thermal barrier coating and a coating method using the same.

1. (A) a resin component that forms a coating film having a refractive index in the range of 1.3 to 1.6, and

(B) a white pigment having an average primary particle diameter in the range of 500 to 2,000 nm and a refractive index in the range of 1.8 to 3.0;

A coating composition for forming a thermal barrier coating, comprising:

2. The coating composition according to the above item 1, wherein the resin component (A) contains a crosslinked acrylic resin or a non-crosslinked acrylic resin.

3. The coating composition according to the above item 1, wherein the resin component (A) contains a carbonyl group-containing acrylic copolymer and a hydrazine derivative.

4. The coating composition according to the above item 1, wherein the resin component (A) contains a maleimide group-containing acrylic copolymer.

5. The resin component (A) contains an unsaturated fatty acid-modified acrylic resin as described in item 1 above. The coating composition as described in the above.

6. The coating composition according to the above item 1, wherein the white pigment (B) is titanium dioxide and Z or zinc oxide.

7. The coating composition according to the above item 1, wherein the mixing ratio of the white pigment (B) is 10 to 140 parts by weight with respect to 100 parts by weight of the resin component (A).

8. The coating composition according to item 1, further comprising a white pigment (C) having an average primary particle size of less than 40 Onm.

9. The coating composition according to the above item 8, wherein the white pigment (C) is titanium dioxide and Z or zinc oxide.

10. The coating composition according to the above item 8, wherein the mixing ratio of the white pigment (C) is 10 to 140 parts by weight based on 100 parts by weight of the resin component (A).

11. The coating composition according to the above item 8, wherein the weight ratio of the white pigment (B) to the white pigment (C) is in the range of 1090 to 90/10.

12. The coating composition according to item 1, further comprising a coloring pigment (D).

13. The coating composition according to item 12, containing a plurality of chromatic pigments having a complementary color relationship as the coloring pigment ω).

14. An overcoating composition which is the coating composition for forming a heat-shielding film according to item 1 above.

15. In addition to the above item 14, which contains a colored paint (D) and can form a coating film having a lightness (L * value) of 20 to 70 based on the L * a * b * color system specified in JISZ 8729. The top coating composition according to any one of the preceding claims.

16. An undercoat paint composition which is the paint composition for forming a heat-shielding film according to item 1 above.

17. The undercoat paint composition according to the above item 16, which can form a coating film having a lightness (L * value) of 70 to 98 based on the L * a * b * color system specified in JIS Z 8729.

18. A coating method in which the top coat composition according to the above item 14 is applied in a single layer on an object to be coated.

19. A coating method in which, after a base coat composition is applied to an object to be coated, the top coat composition according to item 14 above is applied on the coated surface.

20. A coating method in which the undercoat composition according to item 16 is applied to an object to be coated, and then the topcoat composition is applied on the coated surface. 21. The coating method according to the above item 20, wherein the top coating composition is a coating composition containing a perylene pigment.

The invention's effect

According to the coating composition for forming a thermal barrier coating of the present invention, the refractive index of the coating of the resin component (A) and the average particle diameter and the refractive index of the white pigment (B) are adjusted to be within specific ranges, respectively. The following remarkable effects can be obtained.

(1) A single layer or multiple layers of a coating film having an excellent heat shielding effect, sufficient base concealing property and gloss can be formed on various objects to be coated such as buildings. Therefore, it is possible to contribute to suppression of temperature rise inside the object to be coated.

(2) By selecting the type and the like of the resin component (II), it is possible to impart functions such as contamination resistance and weather resistance to the formed coating film.

(3) By adding a coloring pigment to the coating composition and using it as a top coating, it is possible to obtain a coating film having an excellent heat-shielding effect and a rich color tone variation such as a dark color. It is possible. Therefore, by coating the outer wall, the roof, and the like of an object to be coated such as a building, it is possible to suppress an increase in the temperature inside the object to be coated and to obtain an appearance having excellent aesthetics.

(4) By adjusting the coating film formed from the coating composition to have a specific brightness and using it as an undercoating material, an undercoating film having excellent heat shielding effect and concealing property can be formed. Therefore, it is possible to form a multilayer coating film having a good appearance and an excellent heat-shielding effect without adversely affecting the color tone of the coating film of the overcoat paint applied on the undercoat paint film. According to such a multi-layer coating film, even if the top coating film has a dark color appearance, for example, the appearance of the object to be coated is maintained for a long time without causing a poor appearance as the entire multi-layer coating film. Meanwhile, the internal temperature rise can be suppressed.

Coating composition for forming thermal barrier coating

The coating composition for forming a heat-shielding film of the present invention has a resin component (Α) for forming a film having a refractive index in the range of 1.3 to 1.6, and an average primary particle diameter of 500 to 500. It contains a white pigment (B) in the range of 2,000 nm and the refractive index in the range of 1.8 to 3.0.

In the coating composition of the present invention, the white pigment (B) is added to the resin component (A). By the combination, the effect of reflecting and scattering the infrared rays of the white pigment (B) is effectively exhibited, and the obtained coating film has an excellent heat shielding effect. Here, the above-mentioned action of the white pigment (B) is an action of efficiently reflecting and scattering near-infrared rays having a wavelength of about 780 to 2,100 nm.

Resin component (A)

The resin component (A) forms a film having a refractive index in the range of 1.30 to 1.60, preferably 1.35 to; L. 58, more preferably 1.40 to 1.55. . When the refractive index of the coating of the resin component (A) exceeds 1.60, not only does the efficiency of reflection and scattering of infrared rays by the white pigment (B) decrease, but also the concealment and appearance of the coating may decrease. It is not preferable.

In addition, in order for the white pigment (B) to efficiently reflect and scatter infrared rays, the refractive index of the coating of the resin component (A) must be smaller than the refractive index of the white pigment (B). The value obtained by subtracting the refractive index of the resin component (A) coating from the refractive index of the white pigment (B) is 0.20 or more, preferably 0.45 to: L. 40, and more preferably 0.80 to 1. 00. If the difference in refractive index is less than 0.20, the rate of transmission of infrared rays increases, which is not preferable.

In the present specification, the refractive index of the coating of the resin component (A) is obtained by preparing a free coating of the resin component (A) and measuring the free coating with an Abbe refractometer described in JIS K0062.

The content of the resin component (A) is not limited as long as the film formed by the component has a refractive index in the above range. The resin component (A) may be any of a water-soluble or water-dispersible resin, a resin soluble or dispersible in an organic solvent, and a powder resin. The resin component (A) is desirably a resin that can be dried at room temperature because the coating composition of the present invention is mainly used for painting outdoors such as the exterior of buildings.

Further, the resin component (A) may be either a crosslinked resin or a non-crosslinked resin.

The crosslinkable resin is usually used in a state in which a self-crosslinkable resin or a crosslinkable functional group-containing resin and a crosslinker are dissolved or dispersed in a medium. The medium is water and Z or Use an organic solvent. A coating composition containing a cross-linkable resin undergoes a cross-linking reaction due to volatilization of a medium after coating to form a three-dimensional cross-linked coating film.

On the other hand, non-crosslinked resins are usually used in a state of being dissolved or dispersed in a medium. As the medium, water and Z or an organic solvent are used. A coating composition containing a non-crosslinkable resin forms a coating film by volatilization of the medium after coating. Examples of the non-crosslinked resin include a cellulose derivative, an acrylic resin, a urethane resin, a vinyl chloride resin, a fluorine resin, an alkyd resin, a vinyl acetate resin, and a styrene-butadiene resin.

It is preferable to use a crosslinked acrylic resin or a non-crosslinked acrylic resin as the resin component (A), since the gloss of a coating film formed from the composition of the present invention is good.

The resin component (A) includes a combination of a acrylonitrile-containing acrylic copolymer and a hydrazine derivative as a crosslinking agent, a maleimide group-containing acrylic copolymer, an unsaturated fatty acid-modified acrylic copolymer, and the like. Mold resins are preferred. The carbonyl-group-containing acrylic copolymer may be used alone as a non-crosslinked resin. It is preferable to use the acrylic copolymer containing a sulfonic acid group, which is the resin component (A), as an emulsion.

The acrylonitrile copolymer containing a force-rubonyl group can be prepared, for example, according to a general emulsion polymerization method, in the presence of a surfactant as a emulsifier, in the presence of a surfactant as a force-ruponyl group and other ethylenically unsaturated monomers. It can be easily produced by copolymerizing the monomer.

The ethylenically unsaturated monomer containing a thioponyl group is a monomer having at least one carbonyl-containing group selected from an aldehyde group and a keto group and a polymerizable double bond in one molecule. Examples of the monomer include (meth) acrolein, formyl styrene, vinyl alkyl ketone having 4 to 7 carbon atoms, acetoacetoxyl (meth) acrylate, and diacetone (meth) acrylamide. Examples of the vinyl alkyl ketone having 4 to 7 carbon atoms include vinyl methyl ketone, vinyl ethyl ketone, vinyl butyl ketone, and the like.

Other ethylenically unsaturated monomers include, for example, methyl (meth) acrylate To ethyl, methyl (meth) acrylate, propyl (meth) acrylate, n-butyl (meth) acrylate, isobutyl (meth) acrylate, pentyl (meth) acrylate, hexyl (meth) acrylate, 2-ethyl Alkyl (meth) acrylates such as xyl (meth) acrylate, lauryl (meth) acrylate, and stearyl (meth) acrylate; cycloaliphatic (meth) acrylates such as cyclohexyl (meth) acrylate and isopornyl (meth) acrylate Aralkyl (meth) acrylates such as benzyl (meth) acrylate; alkoxyalkyl (meth) acrylates such as 2-methoxyethyl (meth) acrylate and 2-ethoxyxyl (meth) acrylate; hydroxyethyl (meth) acrylate Uto, hydro Hydroxyalkyl (meth) acrylates such as cypropyl (meth) acrylate; vinyl ester compounds such as vinyl acetate and vinyl propionate; vinyl aromatic compounds such as styrene and α-methylstyrene; perfluoroalkyl (methyl ) Acrylate, glycidyl (meth) acrylate, Ν, Ν-ethylethylaminoethyl (meth) acrylate, (meth) acrylic acid, (meth) acrylamide, (meth) acrylonitrile and the like. Among these, styrene, an alkyl (meth) acrylate having an alkyl group having 1 to 8 carbon atoms, and (meth) are preferable monomers in view of the refractive index and copolymerizability of the obtained copolymer film. Acrylic acid, (meth) acrylamide and the like can be mentioned.

By combining a hydrazine derivative with an acrylyl copolymer emulsion containing a sulfonic acid group, a resin component capable of crosslinking at room temperature can be formed, and a crosslinked coating film having excellent water resistance, weather resistance, and the like can be formed.

Examples of the hydrazine derivative include compounds having at least two functional groups per molecule of at least one kind selected from a hydrazide group, a semicarbazide group, and a hydrazone group. The two or more functional groups may be the same or different. Examples of the compound having two or more hydrazide groups per molecule include, for example, a saturated compound having 2 to 18 carbon atoms such as oxalic acid dihydrazide, malonic acid dihydrazide, succinic acid dihydrazide, daltaric acid dihydrazide, adipic acid dihydrazide, and sebacic acid dihydrazide. Dihydrazide of aliphatic dicarboxylic acid; monoolefinic unsaturated dical such as maleic dihydrazide, fumaric dihydrazide, itaconic dihydrazide Dihydrazide of boric acid; dihydrazide of phthalic acid, terephthalic acid or isophthalic acid; dihydrazide of pyromellitic acid, trihydrazide or tetrahydrazide; trihydrazide triacetate, trihydrazide citrate, 1,2,4- Benzentrihydrazide; ethylenediaminetetraacetic acid tetrahydrazide, 1,4,5,8-naphthoic acid tetrahydrazide; polyhydrazide obtained by reacting a low polymer having a lower alkyl ester group of carboxylic acid with hydrazine or hydrazine hydrate; Is mentioned.

As the hydrazide compound, for example, dihydrazide of a saturated fatty acid dicarboxylic acid such as adipic dihydrazide and succinic dihydrazide is preferable.

Examples of the compound having two or more semicarbazide groups per molecule include, for example, an excess of N, N-substituted hydrazine or the above hydrazide in a dihydrazide carbonate, a bisemicarbazide; a diisocyanate compound or a polyisocyanate compound derived therefrom. An aqueous polyfunctional semicarbazide obtained by excessively reacting the above-mentioned dihydrazide with an isocyanate group in a reaction product of the polyisocyanate compound and a hydrophilic group-containing active hydrogen compound; A mixture of a polyfunctional semicarbazide and an aqueous polyfunctional semicarbazide is exemplified. Hexamethylene diisocyanate, isophorone diisocyanate and the like are mentioned as the di-socyanate compound. Examples of the N, N-substituted hydrazine include N, N-dimethylhydrazine and the like. Examples of the active hydrogen compound having a hydrophilic group include polyether polyols and polyethylene glycol monoalkyl ethers.

As the compound having two or more hydrazone groups per molecule, for example, bis-cetyldihydrazone can be suitably used.

The above-mentioned hydrazine derivatives can be used alone or in combination of two or more. The amount of the hydrazine derivative to be used is such that the refractive index of the coating of the resin component (A) falls within the range of 1.30 to 1.60. On the other hand, the content is preferably in the range of about 0.1 to 10.0% by weight.

The maleimide group-containing acrylic copolymer, which is the resin component (A), is used in combination with an emulsion. Then, it is preferable to use. The maleimide group-containing acrylic copolymer emulsion has a property that the maleimide group is dimerized by light irradiation, so that a self-crosslinking reaction proceeds at room temperature under sunlight irradiation.

The emulsion is prepared by copolymerizing a maleimide group-containing ethylenically unsaturated monomer and another ethylenically unsaturated monomer in the presence of a surfactant as an emulsifier, for example, according to a general emulsion polymerization method. Thus, it can be easily manufactured.

As the maleimide group-containing ethylenically unsaturated monomer, compounds represented by the following formulas (1) and (2) are preferably used.

In each formula, R ¹ and R ² independently represent a hydrogen atom or a methyl group. R ³ and R ⁴ independently represent an alkyl group having 4 or less carbon atoms. n shows the integer of 1-6. As the other ethylenically unsaturated monomers, those similar to those listed as the other ethylenically unsaturated monomers used for producing the acrylonitrile-containing acrylyl copolymer emulsion can be used.

As the resin component (A), a carbonyl group-containing acrylic copolymer emulsion and a maleimide group-containing acrylic copolymer emulsion can be used in combination. In this case, the combination ratio is about 39-97 Z3, preferably about 1090-90 / 10 in terms of the weight ratio of the solid content of the former Z and the latter. In the case of this combination, The hydrazine derivative can be used in combination with the acryl resin containing a ponyl group.

As the resin component (A), an organic solvent-soluble unsaturated fatty acid-modified acrylic resin can be preferably used. The unsaturated fatty acid-modified acrylic resin undergoes self-crosslinking by oxidative polymerization at room temperature. In addition, the unsaturated fatty acid component in the resin can effectively suppress a decrease in the gloss of the coating film, which may occur due to the incorporation of the white pigment (B). The unsaturated fatty acid-modified acrylic resin is prepared, for example, by copolymerizing an epoxy group-containing ethylenically unsaturated monomer and other ethylenically unsaturated monomers in the presence of an organic solvent to form an epoxy group-containing acrylyl copolymer. It can be prepared by preparing and subjecting the epoxy group to an addition reaction with an unsaturated fatty acid.

The epoxy group-containing ethylenically unsaturated monomer is a monomer having at least one epoxy group and a polymerizable double bond in one molecule. Examples of the monomer include glycidyl (meth) acrylate,] 3-methyldaricidyl (meth) acrylate, 3,4-epoxycyclohexylmethyl (meth) acrylate, and 3,4-epoxycyclo. Xylethyl (meth) acrylate, 3,4-epoxycyclohexylpropyl (meth) acrylate, aryl glycidyl ether, and the like.

As the other ethylenically unsaturated monomers, those similar to those listed as the other ethylenically unsaturated monomers used in the production of the acrylonitrile-containing acrylyl copolymer emulsion can be used.

Unsaturated fatty acids are introduced to oxidatively cure the formed coating. Examples of the fatty acids include fish oil fatty acids, dehydrated castor oil fatty acids, safflower oil fatty acids, linseed oil fatty acids, soybean oil fatty acids, sesame oil fatty acids, poppy oil fatty acids, eno oil fatty acids, hemp oil fatty acids, grape kernel oil fatty acids, Corn oil fatty acids, tall oil fatty acids, sunflower oil fatty acids, cottonseed oil fatty acids, walnut oil fatty acids, rubber seed oil fatty acids, and the like.

The fatty acid-modified acrylic resin may be modified with a silicon resin or the like for the purpose of improving weather resistance.

In addition, as the resin component (A), fluorine resin, acrylic resin, polyester resin A two-component resin composition can be used in which a resin containing hydroxyl groups in a resin such as a resin such as a resin, an alkyd resin, a urethane resin, or an epoxy resin is used as a main component, and a crosslinking agent such as a polyisocyanate is mixed immediately before use. . For example, a urethane-curable two-component paint in which a polyisocyanate curing agent is used in combination with a base resin (main agent) containing a hydroxyl group-containing acrylic resin can be preferably used.

The resin component (A) can contain an organosilicate compound as a stain-proofing agent, if necessary. This compound has the advantage that the formed coating film becomes hydrophilic and its surface is easily washed with rainwater or the like, so that it is less likely to be stained. Examples of the organosilicate compound include a linear condensate represented by the following formula (3).

(R ^b 0) (3)

In the formula, R ⁵ independently represents a hydrogen atom or a hydrocarbon group having 1 to 10 carbon atoms. m represents 1 to an integer of L00.

Examples of the hydrocarbon group having 1 to 10 carbon atoms include methyl group, ethyl group, n-propyl group, i-propyl group, n-butyl group, i-butyl group, t-butyl group, n- Alkyl groups such as pentyl group, i-pentyl group, n-hexyl group, i-hexyl group and n-octyl group; aryl groups such as phenyl group are preferred.

As the organosilicate compound of the above formula (3), those in which R ⁵ is a lower alkyl group having 1 to 4 carbon atoms and m is 2 to 15 are more preferable.

Examples of the organosilicate compound include a branched compound or a cyclic compound in addition to the linear compound represented by the above formula (3).

Further, when the resin component (B) is aqueous, the above organosilicate compound may be reacted with a polyalkylene glycol-based compound such as polyethylene glycol or polypropylene glycol to be blended as a modified organosilicate compound. Good.

Even if the resin component (A) contains a resin used for dispersing a pigment, Good. As the pigment dispersing resin, known anionic resins, nonionic resins, and cation resins can be used without limitation. In order to improve the dispersibility of the white pigment (B), it is preferable to use an anionic resin, particularly a carboxylic acid resin. When the resin component (A) is aqueous, it is preferable to use a polycarboxylic acid resin, and when the resin component is an organic solvent type, it is preferable to use a hydroxyl group-containing carboxylic ester resin. The mixing amount of the dispersing resin is preferably about 1 to 10% by weight based on all the pigments contained in the coating composition.

White pigment (B)

The white pigment (B) used in the composition of the present invention imparts heat shielding property to the formed coating film, and has an average primary particle diameter of 500 to 2,000 nm, preferably 550 nm. 11,600 nm, more preferably in the range of 600〜1,400 nm, and the refractive index is 1.8 03.0, preferably 1.9〜. It is in the range of 2.80, preferably 1.95 to 2.70.

Since the white pigment (B) has the above particle diameter and refractive index, it can efficiently reflect and scatter near infrared rays having a wavelength of about 780 to 2,100 nm in the coating film. The effect as a thermal pigment can be exhibited. Effective white pigments include titanium dioxide and zinc oxide, and it is preferable to use at least one of these. It is particularly preferred to use titanium dioxide.

If the average primary particle size of the white pigment (B) is less than 50 O nm, visible light can be scattered efficiently, but it will transmit infrared light with a wavelength of about 780 to 2,100 nm. In other words, the heat shielding effect of the formed coating film becomes insufficient. On the other hand, when it exceeds 2,000 nm, the concealing property and gloss of the formed coating film are undesirably reduced. On the other hand, when the refractive index is less than 1.8, the heat shielding effect of the formed coating film is not sufficient, and it is not preferable from the viewpoint of concealment.

Here, the average primary particle diameter is an average value of the particle diameters of the individual independent pigment particles. In general, pigment particles are present in an agglomerated state, so it is difficult for ordinary particle size distribution analyzers to measure particles separately from individual agglomerated particles. Accordingly, it is possible to determine the average particle diameter of the independent pigment particles. In the present specification, the “average primary particle size” of the pigment is determined by observation with an electron microscope. The “refractive index” of the pigment is a value measured by an Abbe's refractometer described in JIS K 062.

In the present invention, the crystal system of titanium dioxide as the white pigment (B) may be a rutile type or an anase type as long as the average particle diameter and the refractive index are in the ranges described above. Further, the surface of titanium dioxide may be coated with an inorganic oxide such as aluminum oxide, zirconium oxide, or silicon dioxide; or an organic compound such as amine or alcohol.

In the present invention, from the viewpoint of obtaining a sufficient heat shielding effect, the pigment volume concentration (Pigment volume concentration) of the white pigment (B) contained in the formed coating film is about 5 to 30%. Preferably, it is about 6 to 25%. Therefore, a white pigment (B) is blended with the resin component (A) so as to have such a pigment volume concentration. The pigment volume concentration is the volume percentage of the pigment contained in the coating film. The pigment volume concentration can be calculated as the ratio of the total area occupied by the pigment to the area of the cross section of the coating film measured by a scanning electron microscope.

White pigment (C)

The coating composition for forming a heat-shielding film of the present invention may further contain a white pigment (C) having an average primary particle diameter of less than 40 O nm, preferably about 200 to 300 nm. It is preferable from the viewpoint that the undercoat concealing property of the coating film formed from the composition of the present invention can be improved.

Examples of such white pigment (C) include titanium dioxide and zinc oxide, and it is preferable to use at least one of these. It is particularly preferred to use titanium dioxide.

The crystal form of the titanium dioxide (C) may be either a rutile type or an anatase type, but a rutile type is preferred because the formed coating film has excellent concealing properties and weather resistance. .

Color pigment (D)

The coating composition for forming a thermal barrier coating of the present invention may further contain a color pigment (D). Color pigment (D) refers to a pigment for imparting a desired color to a coating film. Usually, they can be classified into achromatic pigments and chromatic pigments.

Achromatic pigments include white pigments and black pigments. Examples of the white pigment include lead white, basic lead sulfate, lead sulfate, lithobone, zinc sulfide, antimony white, white pigment (B), and titanium dioxide or zinc dioxide other than white pigment (C). Examples of black pigments include azomethine pigments, perylene pigments, and dalaite.

Among the above black pigments, perylene pigments are preferred because they hardly absorb infrared rays and the heat-shielding effect of the resulting coating film is small. On the other hand, a car pump rack can be used as the black pigment. However, the car pump rack is not preferable because it easily absorbs infrared rays and greatly reduces the heat shielding effect of the obtained coating film.

The chromatic pigments include coloring pigments other than the achromatic pigment. For example, yellow pigments such as yellow iron oxide, titanium yellow, monoazo yellow, condensed yellow, azomethine yellow, bismuth vanadate, benzimidazolone, isoindolinone, isoindolin, quinophthalone, benzidine yellow, permanent yellow, etc .; Orange pigments; red pigments such as red iron oxide, naphthol AS-based azo red, anthanthuron, anthraquinonyl red, perylene maroon, quinacridone-based red pigments, diketopyrrolopyrrole, watching red, and pigments; cobalt purple; Purple pigments such as quinacridone violet and dioxazine violet; blue pigments such as cobalt blue, phthalocyanine blue, and slenbl; green pigments such as phthalocyanine green; Rukoto can.

The coloring pigment (D) may be used alone or as a combination of two or more as needed.

In the present invention, by including a plurality of chromatic color pigments having a complementary color relationship as the color pigment (D), a dark color coating film can be formed even in the presence of the white pigment (B). A coating film with a wide range of brightness can be obtained.

The plurality of chromatic pigments having a complementary color relationship include, for example, chromatic two-color pigments that are located at almost opposite positions on the Munsell hue circle. Examples of combinations of chromatic colors that have a complementary color relationship include red and green, blue and orange, yellow and bluish violet, and purple and yellow-green. The

Composition and preparation method of coating composition for forming thermal barrier coating

In the coating composition for forming a heat-shielding film of the present invention, the blending ratio of the white pigment (B) is preferably about 10 to 140 parts by weight with respect to 100 parts by weight of the resin component (A). About 5 to 120 parts by weight is more preferable. When the blending amount of the white pigment (B) is within this range, the pigment volume concentration of the white pigment (B) contained in the formed coating film can be within the range of about 5 to 30%. A heat shielding effect can be obtained.

When the composition of the present invention contains a white pigment (C), the mixing ratio of the white pigment (C) is about 10 to 140 parts by weight based on 100 parts by weight of the resin component (A). More preferably, about 15 to 120 parts by weight is more preferable. When the blending amount of the white pigment (C) is within this range, a coating film having a sufficient undercoat hiding property can be obtained.

In this case, the weight ratio of the white pigment (B) to the white pigment (C) is preferably in the range of about 10/90 to 90/10, and 20 Z80 to 80. More preferably, it is in the range of about Z 20. Within this range, white pigment (Β) and white pigment

By using (C) in combination, it is possible to improve both the heat shielding effect of the formed coating film and the concealing property of the base.

When the coating composition of the present invention contains the color pigment (D), the content is not limited, and the amount necessary for obtaining a desired color of the coating film can be blended. However, when carbon black is blended as a coloring pigment, the amount of the resin coating is preferably about 0.1 part by weight or less with respect to 100 parts by weight of the resin component (Α) so that the heat shielding effect of the resulting coating film is not significantly reduced. It is desirable to keep it to a small amount.

The coating composition for forming a heat-shielding film of the present invention may contain, if necessary, an extender, an anti-pigment pigment, a glitter pigment, a surface conditioner, a surfactant, a curing catalyst, a dispersant, a defoamer, and a thickener. It may contain paint additives such as a film-forming aid, a preservative, an antifreezing agent, a curing accelerator, and a reaction retardant.

Examples of the above-mentioned extender pigment include Bali evening powder, precipitated barium sulfate, barium carbonate, calcium carbonate, gypsum, clay, silica, white carbon, diatomaceous earth, evening silk, magnesium carbonate, alumina white, Daros white, and the like. You can list them. The coating composition for forming a thermal barrier coating of the present invention can be prepared by mixing the above-described components according to a known method. When the resin component is in the form of an organic solvent solution, emulsion, or the like, it can be mixed as it is. The pigment component may be mixed with a dispersing resin to form a paste, and then mixed. Further, at the time of mixing each component, an organic solvent, water or a mixture thereof may be added as necessary.

The coating composition of the present invention is preferably a liquid coating composition having a solid content of about 40 to 80% by weight. The liquid coating composition may be either an organic solvent type or an aqueous type.

The organic solvent contained in the composition of the present invention may be the one used at the time of producing each component, or may be the one added at the time of mixing each component.

Examples of the organic solvent that can be used in the composition of the present invention include aliphatic solvents such as n-hexane, n-hexane, 2,2,2-trimethylpentane, isooctane, n-nonane, cyclohexan, and methylcyclohexane. Hydrocarbon solvents; aromatic hydrocarbon solvents such as benzene, toluene, xylene, and ethylbenzene; mineral spirits, petroleum hydrocarbon mixed solvents with a C9 aromatic hydrocarbon content of 95% by weight or more, petroleum ether, Petroleum solvents such as petroleum benzine and petroleum naphtha; ketone solvents such as methyl ethyl ketone and methyl isobutyl ketone; ester solvents such as ethyl acetate and isobutyl acetate; ether solvents such as ethylene glycol monobutyl ether; Alcohol solvents such as isopropyl alcohol, n-butyl alcohol and isopropyl alcohol Rukoto can.

The above organic solvents can be used alone or in combination of two or more. Further, if necessary, it can be used by mixing with water.

Uses of coating compositions for forming thermal barrier coatings

The coating composition for forming a heat-shielding film of the present invention is used as a top-coat paint for a single-layer finish, a top-coat paint or a double-coat finish for a two-layer finish when forming a heat-shielding film on various buildings and the like. be able to. Also, it can be used as an intermediate coating for a multilayer coating film of three or more layers.

When the paint composition of the present invention is used as a top coat, a coloring pigment (D) is blended. And a composition capable of forming a coating film having a lightness (L * value) of about 20 to 70, preferably about 22 to 68, based on the L * a * b * color system specified in JISZ 8729. Thus, a coating film having a dark appearance can be formed.

In order to obtain a coating film in the range of the above L * value, the white pigment (B) and the color pigment (D) are mixed in a weight ratio of white pigment (B) / color pigment (D) of about 95 to 5 to 5Z95, Preferably, it is preferably in the range of about 90 to 10/60/40.

The L * value is an index of the lightness of the coating film, where 100 indicates pure white and 0 indicates pure black.

The L * value can be measured using a known colorimeter.

When the coating composition of the present invention is used as a top coat for a single-layer finish or used as an undercoat for a two-layer finish, the elongation at break of the formed coating film is 80 to 500% at 20 ° 〇. And more preferably in the range of about 100 to 400%. When the elongation at break is within this range, the formed coating film can follow the occurrence of cracks on the surface to be coated, which is preferable.

When the paint composition of the present invention is used as an undercoat paint, the lightness (L * value) based on the L * a * b * color system specified in JISZ 8729 is about 70 to 98, preferably about 75. By making the composition capable of forming a coating film of about 97, it is possible to prevent a bad influence on color tone such as lightness of an upper coating film of the coating film.

In order to obtain a coating film having the above L * value, the white pigment (B) and the color pigment (D) are required to have a weight ratio of the white pigment (B) and the Z color pigment (D) of about 100Z0 to 90/10. It is more preferable to set it within the range of about 99Z1 to 95/5.

Coating method using coating composition for forming thermal barrier coating

The coating composition for forming a thermal barrier coating of the present invention can be suitably used in various coating methods described below.

Workpiece and coating means

The substrate to which the coating composition of the present invention is applied is not limited as long as it is a substrate on which a heat-shielding film needs to be formed. Preferred substrates include construction structures. Specific examples of the construction structure include buildings such as buildings, houses, factories, warehouses, stores, and schools; storage tanks such as oil tanks and grain tanks. The surface to be coated is preferably an outer wall of a building, a roof, an outer surface of a tank, or the like.

Examples of the material of the surface to be coated include inorganic base materials such as metal, concrete, gypsum board, slate, siding material, porcelain tile, lightweight cellular concrete, mortar, brick, and stone base material; and organic base materials such as wood and plastic. Can be Examples of the metal include iron, zinc, iron-zinc alloy, and aluminum.

Further, a coating film may be already provided on the surface to be coated. Examples of such a coating film include acrylic resin, acrylic urethane resin, polyurethane resin, fluorine resin, silicon acrylic resin, vinyl acetate resin, and epoxy resin films.

If necessary, a coating film such as a well-known sealer or base adjustment agent may be provided on the surface to be coated.

Examples of means for applying the coating composition of the present invention include known coating tools such as a roller, air spray, airless spray, ricin gun, universal gun, and brush. After coating, it is usually dried or dried and crosslinked at room temperature to obtain a dried coating film. However, forced drying can also be performed by heating.

The dry film thickness can be generally in the range of about 10 to 20,000 m, preferably in the range of about 20 to 1,500 m.

Specific coating methods using the coating composition of the present invention include, for example, the following methods I, II and III. ·

Method I is a single-layer finish coating method in which an object to be coated is coated with the topcoat composition of the present invention.

In the case of painting with the above-mentioned single layer finish, the dry film thickness is usually in the range of about 200 to 2,000 m, preferably about 300 to 1,500 / xm. It is preferable to paint. In this case, the same paint composition may be applied a plurality of times so as to be within the range of the dry film thickness.

Method II I is a two-layer finish coating method in which an undercoat composition is applied to an object to be coated, and then the topcoat composition of the present invention is applied on the coated surface.

The undercoat paint composition in Method II is applied to the exterior walls and roofs of buildings Any of the known organic solvent-based paint compositions and water-based paint compositions used as undercoat paints can be used. For example, an aqueous coating composition containing a resin component such as an acrylic resin emulsion, a urethane resin emulsion, an epoxy resin emulsion, an alkyd resin emulsion, and a fatty acid-modified acrylic resin emulsion, and a pigment is preferred.

Method II As the method for applying the undercoat coating composition in I, the same method as in the case of the coating composition of the present invention can be employed.

It is preferable that the undercoat coating composition in the method II be applied so that the dry film thickness is usually in the range of about 10 to 300 m, preferably about 20 to 200 m.

The overcoat composition of the present invention in the method II is usually applied so that the dry film thickness is in the range of about 10 to 150 / im, preferably in the range of about 30 to 100 m. Is preferred.

Method I II is a two-layer finish coating method in which an undercoat composition of the present invention is applied to an object to be coated, and then an overcoat composition is applied on the coated surface.

The undercoat composition of the present invention in Method III is usually applied so that the dry film thickness is in the range of about 20 to 100 m, preferably about 40 to 800 m. Is preferred.

As the top coat composition in Method II, any of the known organic solvent-based paint compositions and water-based paint compositions used as top coats to be applied to exterior walls, roofs and the like of buildings can be used. For example, an aqueous coating composition containing a resin component and a pigment, such as an acrylic resin emulsion, a urethane resin emulsion, a fatty acid-modified acrylic resin emulsion, a fluororesin emulsion, and a vinyl acetate resin emulsion, is preferable. When the exterior wall, roof, etc. of the building have a dark color appearance, the overcoat composition may be a paint composition containing a perylene pigment. It is preferable from the viewpoint that the heat-shielding effect of the two-layer coating film composed of the film and the coating film of the overcoat composition is not reduced.

As a method for applying the top coating composition in the method 111, the same method as in the case of the coating composition of the present invention can be employed. The topcoat composition in Method III is preferably applied such that the dry film thickness is generally in the range of about 10 to 300 m, preferably about 20 to 200 m.

Further, as a coating method other than the above-mentioned methods (1) to (4), a two-layer finish coating method of coating the object to be coated with the undercoat composition of the present invention and then coating the topcoat composition of the present invention on the coated surface. Can also be adopted.

Further, after applying a known undercoat composition to an object to be coated, the coating composition of the present invention is applied as an intermediate coating composition, and then a known topcoat composition is applied on the intermediate coating surface. A three-layer finish painting method can also be adopted.

Thus, using the coating composition of the present invention, it is possible to form a coating film having an excellent heat-shielding effect on various kinds of objects to be coated. Brief Description of Drawings

FIG. 1 is a cross-sectional view schematically showing a temperature measuring device used for a test of a thermal barrier effect of a coating film. In FIG. 1, reference numeral 1 denotes a light source, 2 denotes a free coating film for a test, 3 denotes a styrofoam box, and 4 to 6 denote thermocouple thermometers. BEST MODE FOR CARRYING OUT THE INVENTION

Hereinafter, the present invention will be described more specifically with reference to Production Examples, Examples, and Comparative Examples.

In each example, “parts” indicates “parts by weight”. The average primary particle size of the pigment was determined by observation using an electron microscope (trade name “LUZEX AP”, manufactured by NIRECO Co., Ltd.). The L * value based on the L * a * b * color system specified in JISZ 8729 is measured using a colorimeter (trade name “Karaichi Computer SM-7”, manufactured by Suga Test Instruments Co., Ltd.). It was measured.

Manufacture of pigment paste

The following components for a pigment paste were placed in a 1-liter stainless steel container, and stirred for 30 minutes with a stirrer to form an aqueous pigment paste (P-1). Water 100 parts Ethylene glycol 40 parts

Dispersion resin (Note 1) 20 parts

Antifoam (Note 2) 20 parts

Thickener (Note 3) 20 parts

Clay (Note 4) 100 parts

Titanium dioxide powder (Note 5) 120 parts

Titanium dioxide powder (Note 6) 120 parts

The above (Note 1) to (Note 6) indicate the following.

(Note 1) Dispersing resin: brand name “Nobcospars 44C”, manufactured by San Nopco, sodium polycarboxylate resin, solid content 43% by weight.

(Note 2) Antifoaming agent: brand name "SN Deformer 364", manufactured by San Nopco.

(Note 3) Thickener: Fuji Chemical HEC KF 100, manufactured by Fuji Chemical. (Note 4) Clay: trade name “P〇LYGR〇SS 90”, manufactured by J. M. Huber, average particle diameter 5 zm, refractive index 1.30.

(Note 5) Titanium dioxide powder: trade name “TI IIXJR—605”, manufactured by Teica Co., Ltd., refractive index 2.72, average primary particle diameter 250 nm.

(Note 6) Titanium dioxide powder: trade name “TI IIXR_1000”, manufactured by Tika Co., Ltd., refractive index 2.72, average primary particle diameter 1,000 nm.

Production Example 2

A water-based pigment paste was prepared in the same manner as in Production Example 1, except that titanium dioxide powder (Note 5) was not used in 120 parts and that the amount of titanium dioxide powder (Note 6) used was 240 parts. (P-2) was created.

Production Example 3

The aqueous pigment paste (P-3) was prepared in the same manner as in Production Example 1 except that 120 parts of zinc oxide powder (Note 7) was used instead of 120 parts of titanium dioxide powder (Note 6). Created.

The above (Note 7) indicates the following.

(Note 7) Zinc oxide powder: Trade name “2 kinds of zinc oxide”, manufactured by Sakai Chemical Industry Co., Ltd. Ratio 2.00, average primary particle diameter 600 nm.

Production Example 4

The aqueous pigment paste was prepared in the same manner as in Production Example 1 except that 120 parts of the titanium dioxide powder (Note 6) was not used and 240 parts of the titanium dioxide powder (Note 5) was used. (P-4) was created.

Production Example 5

The following ingredients were placed in a 1-liter stainless steel container, and stirred and dispersed for 30 minutes with a stirrer to prepare an organic solvent-based pigment paste (P-5).

100 Mineral Spirits

Dispersion resin (Note 8) 40 parts

Antifoam (Note 9) 20 parts

Titanium dioxide powder (Note 6) 240 parts

The above (Note 8) and (Note 9) indicate the following.

(Note 8) Dispersion resin: trade name “BYK_109”, manufactured by BYK Chemie Co., Ltd., hydroxyl group-containing carboxylic acid ester resin, solid content 100% by weight.

(Note 9) Antifoaming agent: trade name "BYK-066", manufactured by Big Chem Co., Ltd.

Production Example 6

Organic solvent-based pigment paste (P-6) was prepared in the same manner as in Production Example 5, except that 240 parts of titanium dioxide powder (Note 6) was used instead of 240 parts of titanium dioxide powder (Note 6). ) created.

The above (Note 10) indicates the following.

(Note 10) Titanium dioxide powder: trade name “TI TANN I X JR-805”, manufactured by Tika Co., Ltd., refractive index 2.72, average primary particle diameter 250 nm.

Production Example 7

In the same manner as in Production Example 5, except that 240 parts of titanium dioxide powder (Note 5) was used instead of 240 parts of titanium dioxide powder (Note 6), organic solvent-based paint paste (P- 7) was created.

Production Example 8

In Preparation Example 5, zinc oxide powder was used instead of 240 parts of titanium dioxide powder (Note 6). (Note 7) An organic solvent-based pigment base (P-8) was prepared in the same manner as in Production Example 5 except that 240 parts were used.

Of Acryl Copolymer Emulsion (a) Containing Sulfonyl Group

Production Example 9

In a flask, add 36 parts of deionized water and 0.36 parts of anionic surfactant (Note 11) .After purging with nitrogen, heat to 80 ° C, and maintain the internal solution at 80 ° C. After adding 1 part of ammonium persulfate, a monomer emulsion having the following composition was added dropwise over 3 hours.

Monomer emulsion composition

Deionized water 52. 4 咅 15

Diaset: 10 copies

Acrylic acid 0.5¾

17.5 咅

Methyl methacrylate 18 parts

'2-ethylhexyl acrylate 18 parts

n-Butyl acrylate 36 parts

Anionic surfactant (Note 11) 9.6¾

Ammonia persulfate 0.2 parts

From 30 minutes to 30 minutes after the completion of the dropwise addition, a solution prepared by dissolving 0.1 part of ammonium persulfate in 1 part of deionized water was added dropwise, and the mixture was kept at 80 for 2 hours to obtain an emulsion (a).

The above (Note 11) indicates the following.

(Note 11) Anionic surfactant: brand name “Newcol 707 SF”, manufactured by Japan Emulsifier Co., Ltd., ammonium sulfate having a polyoxyethylene chain, solid content 30% by weight.

The obtained resin emulsion was applied to a glass plate (15 OmmX 10 OmmX 2 mm) using a doctor blade, dried and cured at a temperature of 23 ° C and a relative humidity of 50% for 2 weeks. As a result, a free coating film having a dry film thickness of about 1 mm was obtained. Using the Abbe refractometer described in JISK 0062, the refractive index of this free coating film, The measured value was 1.52.

Production of maleimide group-containing acrylic copolymer emulsion (b)

Production Example 10

In a flask, 10 parts of a maleimide group-containing monomer represented by the following formula (4), 50 parts of n-butyl methacrylate, 25 parts of methyl methacrylate, 14 parts of n-butyl acrylate and 14 parts of methyl methacrylate Parts of the mixture, and 100 parts of deionized water and a radical polymerizable surfactant (trade name “AQUALON HS10”, manufactured by Daiichi Pharmaceutical Co., Ltd.), polymerizable unsaturated groups and oxyethylene groups 0.5 part of ammonium sulfate having the above), and a monomer emulsion was prepared using a rotary homomixer.

On the other hand, the inside of the flask containing 45 parts of deionized water and 0.5 part of a radical polymerizable surfactant (“AQUALON HS10”) was purged with nitrogen, and then heated to a temperature of 80 ° C. While maintaining the temperature at 80 ° C., 1 part of ammonium persulfate and 2% by weight of the above monomer emulsion were added thereto, and 15 minutes after the addition, the remaining monomer emulsion was added for 2 hours. Then, the mixture was aged for 2 hours. After aging, the mixture was cooled, and 3 parts of 10% by weight ammonia water was added dropwise as a neutralizing agent to obtain a resin emulsion (b).

From this emulsion, a free coating film was prepared in the same manner as in Production Example 9, and the refractive index was measured to be 1.52.

Production of Fatty Acid-Modified Acrylic Resin (c) 100 parts of mineral spirits were charged into a flask, and the temperature was raised to 115 ° C. with stirring while flowing nitrogen gas. Next, while maintaining the temperature at 115 ° C, 25 parts of len, 15 parts of n-butyl methacrylate, 20 parts of i-butyl methacrylate, 20 parts of 2-ethylhexyl acrylate, 20 parts of glycidyl methacrylate and 1 part of 2,2'-azobisisobutyronitrile The mixture was allowed to drip over 4 hours. After aging at 115 ° C for 2 hours, the temperature was raised to 140, and 30 parts of linoleic acid fatty acid and 0.4 parts of N, N-dimethylaminoethanol as a reaction catalyst were added. The mixture was kept for 5 hours to perform an addition reaction of the fatty acid. The resin acid value was tracked by the KΗ titration method, and the time when the resin acid value became 1.0 or less was determined as the end point. After completion of the reaction, 45 parts of xylene was added to dilute the mixture to obtain a brown transparent and viscous fatty acid-modified copolymer solution having a nonvolatile content of 50% by weight. Next, the mixture was cooled to 100 ° C, and the flask was equipped with a water separator. Silicon resin (polyalkylphenylsiloxane having silanol groups, trade name “SH-6018”, Dow Corning Toray Silicone Co., Ltd.) 20 parts, 14 parts of mineral spirits, 6 parts of xylene and 0.20 parts of tetra-n-butyl titanate as a reaction catalyst, and the temperature is raised to 165 ° C, and the water is separated by a water separator in a reflux system. The mixture was reacted for 5 hours while separating to obtain a brown transparent viscous silicone-containing fatty acid-modified acrylic resin (c) having a nonvolatile content of about 50% by weight.

Production of acrylic copolymer emulsion (d)

Production Example 12

Monomer emulsion composition

Deionized water 52. 4 parts

Acrylic acid 0.5 part

Styrene 17.5 parts

Methyl methacrylate 28 parts

(2) Ethylhexylacrylate 18 parts

n-Butyl acrylate 36 parts

Anionic surfactant (Note 11) 9.6 parts 0.2 parts of ammonium persulfate From 30 minutes to 30 minutes after completion of the dropping, a solution prepared by dissolving 0.1 part of ammonium persulfate in 1 part of deionized water is added dropwise, and kept at 80 ° C for 2 hours. Emulsion (d) was obtained.

Production of resin emulsion (R-1)

Production Example 13

550 parts of a mixture of the above emulsion (a) and emulsion (b) in a 2 liter stainless steel container such that the solid content weight ratio becomes emulsion (a): emulsion (b) = 50: 5. 50 parts and 1 part of adipic dihydrazide were added, and the mixture was stirred so as to be uniform to obtain a resin emulsion (R-1).

Production of resin solution (R-2)

Production Example 14

In a 1 liter stainless steel container, 550 parts of an acrylic polyol resin with a solid content of 55% by weight (glass transition temperature 55 ° C, trade name “Acridic A-370”, manufactured by Dainippon Ink and Chemicals, Inc.) 550 parts, mineral spirit 50 parts Was added and stirred uniformly to obtain a resin solution (R-2).

Manufacture of topcoat composition for forming heat-shielding coating

Example 1

In a 1-liter stainless steel container, put 270 parts of the aqueous pigment paste (P-1), 600 parts of resin emulsion (R-1), 2,2,4-trimethyl-1,3-pentanediol monoisobutylate 60 The mixture was added with stirring, and the pH was adjusted to 7 to 9 with ammonia water to obtain an aqueous coating composition.

In this coating composition, the mixing ratio of titanium dioxide powder having an average primary particle diameter of 250 nm to 20 parts by weight of the resin component was 100 parts by weight, and the mixing ratio of titanium dioxide powder having an average primary particle diameter of 1,000 nm was 20 parts. Department.

Here, the resin component in the coating composition is the total amount of the resin solid content of the resin emulsion (R-1) and the resin solid content of the aqueous pigment base (P-1).

Example 2

In Example 1, an aqueous pigment paste was used instead of the aqueous pigment paste (P-1). An aqueous coating composition was obtained in the same manner as in Example 1, except that the same amount of (P-2) was blended.

In this coating composition, the mixing ratio of titanium dioxide powder having an average primary particle diameter of 1,000 nm to 40 parts by weight of the resin component was 40 parts.

Here, the resin component in the coating composition is the total amount of the resin solid content of the resin emulsion (R-1) and the resin solid content of the aqueous pigment paste (P-2).

Example 3

A water-based paint was prepared in the same manner as in Example 1, except that the acrylic copolymer emulsion (d) was blended in the same amount as the solid content in place of the resin emulsion (R-1). A composition was obtained.

Example 4

A two-part urethane-curable organic solvent-based coating composition comprising a base resin and a curing agent was prepared by the following method.

Into a 1-liter stainless steel container, add 280 parts of the organic solvent-based pigment paste (P-5), and further stir 600 parts of the resin solution (R-2) obtained in Production Example 13 while stirring. Was obtained.

Separately, isocyanurate of hexamethylene diisocyanate (trade name “Duranate TSS-100”, manufactured by Asahi Danisei Co., Ltd.) and 50 parts of low-condensed ethyl silicate (trade name “ES —48 ”, manufactured by Colcoat Co., Ltd.), to obtain a curing agent. When used as a paint, 20 parts of the curing agent is added to 100 parts of the solid content of the base resin solution.

The mixing ratio of the titanium dioxide powder having an average primary particle diameter of 1,000 Onm to 100 parts by weight of the resin component in this coating was 50 parts.

Example 5

In a 1-liter stainless steel container, 280 parts of the organic solvent-based pigment paste (P-5) was added, and 600 parts of the fatty acid-modified acrylic resin (c) obtained in Production Example 11 was mixed. The resulting mixture was stirred to obtain a room temperature crosslinking type organic solvent type coating composition.

The mixing ratio of the titanium dioxide powder having an average primary particle diameter of 1,000 nm to 100 parts by weight of the resin component in this coating material was 50 parts.

Manufacture of dark topcoat composition

Example 6

The following ingredients were placed in a 1-liter stainless steel container, stirred for 30 minutes with a stirrer, dispersed, and adjusted to pH 7 to 9 with aqueous ammonia to prepare an aqueous color coating composition (chocolate color). .

Water supply 100 parts

Ethylene glycol 20 parts

Pigment dispersion resin (Note 1) 10 parts

Antifoam (Note 2) 10 parts

Thickener (Note 3) 10 parts

Clay (Note 4) 50 parts

Red pigment paste (Note 12) 80 parts

Green pigment paste (Note 13) 20 parts

Titanium dioxide pigment (Note 6) 60 parts

Resin emulsion obtained in Production Example 9 (a) 500 parts

50 parts of the resin emulsion obtained in Production Example 10 (b)

2, 2, 4 _trimethyl-1,3-pen

Tandiol monoisobutylate 60 parts

The above (Note 12) and (Note 13) indicate the following.

(Note 12) Red pigment paste: trade name “NS BROWN C 522”, manufactured by Sanyo Pigment Co., pigment: red iron oxide (content 50% by weight).

(Note 13) Green pigment paste: NS GREEN 4711 (trade name), manufactured by Sanyo Pigment Co., pigment: phthalocyanine green (content 30% by weight).

Example 7

An aqueous coating composition was obtained in the same manner as in Example 1, except that the same amount of the aqueous pigment paste (P-3) was used instead of the aqueous pigment paste (P-1). It was.

Comparative Example 1

An aqueous coating composition was obtained in the same manner as in Example 1, except that the same amount of the aqueous pigment paste (P-4) was used instead of the aqueous pigment paste (P_l).

Comparative Example 2

The acryl polyol resin was prepared in the same manner as in Example 4 except that the organic solvent-based pigment paste (P-5) was replaced with the same amount of the organic solvent-based pigment paste (P-6). A containing base resin solution was obtained. A two-component urethane-curable organic solvent-based coating composition comprising the base resin solution and the curing agent described in Example 4 was obtained.

Comparative Example 3

In the same manner as in Example 5 except that the same amount of the organic solvent-based pigment paste (P-7) was used instead of the organic solvent-based pigment paste (P-5), An organic solvent type coating composition was obtained.

Comparative Example 4

In a 1-liter stainless steel container, put 280 parts of an organic solvent-based pigment paste (P-8) and add a vinyl chloride resin (trade name "45% Kanevilac LE-Y", manufactured by Kaneka Chemical Co., Inc. 1.75) 600 parts were mixed and stirred to obtain a room temperature drying type organic solvent type coating composition.

For each of the coating compositions obtained in Examples 1 to 7 and Comparative Examples 1 to 4, the refractive index of the resin coating, the pigment volume concentration of the coating and the elongation at break were measured according to the following test methods.

Refractive index of resin coating

A resin composition was prepared by removing the pigment component from each coating composition. This was applied to a glass plate (15 OmmX 10 Ommx 2 mm) using a doctor blade, at a temperature of 23 ° C and a relative humidity of 50%. After drying and curing for 2 weeks under the above conditions, the coating film was peeled off to obtain a free coating film having a dry film thickness of about 1 mm. The refractive index of the free coating film was measured using an Abbe refractometer described in JISK0062. Pigment volume concentration (PVC)

Each coating composition was applied to a glass plate (15 OmmX 10 OmmX 2 mm) using a doctor blade, dried and cured at a temperature of 23 ° (50% relative humidity for 2 weeks), and then coated. The cross section of the free film was photographed with a scanning electron microscope (trade name “J SM-531 OLV”, manufactured by JEOL Ltd.). In the SEM photograph of the cross section of the coating film, a continuous phase based on the resin component and a dispersed phase based on the pigment component were observed. — 8100 ”(manufactured by JEOL Ltd.), and identified dispersed phases originating from titanium dioxide and zinc oxide among the dispersed phases observed in the SEM photograph. For the phase, the major axis and minor axis were converted from the magnification in the SEM photograph, and the average of these was 500 to 2,000 O The dispersed phase having an average primary particle diameter of 1,000 nm was titanium dioxide having an average primary particle diameter of 1,000 nm, and the dispersed phase having an average primary particle diameter of less than 400 nm was titanium dioxide having an average primary particle diameter of 25 Onm. Regarding the dispersed phase caused by the above, the dispersed phase having an average of major axis and minor axis of 500 to 2,000 nm was defined as zinc oxide having an average primary particle diameter of 600 nm.

Among the disperse phases observed in the SEM photograph, the disperse phase caused by each white pigment was specified based on the above criteria, and the ratio of the total area of the disperse phase to the cross-sectional area of the coating film was calculated. The volume concentration (%) was calculated.

Elongation at break (¾)

Each coating composition was applied to release paper (20 OmmX 20 Omm) using a doctor blade, dried and cured at a temperature of 23 ° C and a relative humidity of 50% for 2 weeks. Thus, a free coating having a dry film thickness of about 1 mm was obtained. The elongation at break of the free coating film was measured using a tensile tester (trade name "Autograph AG2000 B", Shimadzu Corporation).

Was measured at a temperature of 20 ° C. and a tensile speed of 20 OmmZ. Table 1 shows the test results. table 1

In Table 1, JR-605, JR-1000 and JR-805 are titanium dioxide powders with an average primary particle diameter of 250 nm “TI TANN IXJR-605” (trade name, Tika Titanium dioxide powder with an average primary particle diameter of 1,00 O nm

“T I ΤΑΝΝI X J R — 100 0” (trade name, manufactured by Tika Co., Ltd.) and titanium dioxide powder with an average primary particle size of 250 nm “T I ΤΑΝΝI X J R—805”

(Trade name, manufactured by Tika Co., Ltd.). In addition, zinc oxide refers to zinc oxide powder having an average primary particle diameter of 60 O nm (trade name “2 types of zinc oxide”, manufactured by Sakai Chemical Industry Co., Ltd.).

Examples 8 to 14 and Comparative Examples 5 to 8

Each coating composition obtained in Examples 1 to 7 and Comparative Examples 1 to 4 was placed on a slate plate (70 mm X 150 mm X 5 mm) so that the dry film thickness became 1,000 m. Doc evening — Coated with a blade and dried at 23 ° C (50% relative humidity) for 14 days to obtain a test coated plate.

Also, except that a glass plate (150 mm x 100 mm x 2 mm) was used instead of the plate, coating and drying were performed in the same manner, and then the dried coating was peeled off to obtain a free coating. Was. With respect to each of the test coated plates obtained above, the gloss, the background concealing property, and the L * value were examined. Further, the heat shielding effect of each free coating film obtained above was examined. Each test method is as follows.

Gloss

The specular glossiness (60 ° Darros) of each test coated plate was measured. The larger the value, the higher the gloss.

Underlay hiding Each test coated plate was visually observed and evaluated according to the following criteria. A indicates that the base is not observable and the opacity is good, and B indicates that the base is observable and the concealment is poor.

Same value

Using a colorimeter (trade name “Color Computer SM-7”, manufactured by Suga Test Instruments Co., Ltd.), the coating film of each test coated plate was converted to the L * a * b * color system specified in JISZ 8729. Based L * values were measured. The heat shielding effect of the free coating film was examined using the temperature measuring device shown in FIG. FIG. 1 is a cross-sectional view schematically showing the apparatus. In FIG. 1, reference numeral 1 denotes a light source, 2 denotes a free coating film for testing, 3 denotes a styrene foam box, and 4 to 6 denote thermocouple thermometers used as temperature sensors.

As the light source 1, an incandescent light bulb (trade name “Reflamp”, 100W, manufactured by Toshiba Corporation) that emits light including infrared rays was used. A free paint film (50 mm x 70 mm) with a dry film thickness of 1,000 m was placed in a hole of the same size as the free paint film provided on the upper surface of Box 3. The distance between the light source 1 and the free coating film 2 was 15 cm. Thermocouple thermometers were installed on the front and back surfaces of the free coating film 2 and inside the box 3, respectively.

Turn on the power of the light source 1 and measure the temperature of the front and back surfaces of the coating film and the inside of the box while irradiating the surface of the free coating film with light including infrared rays, and measure each temperature when each temperature converges to a certain value. Was examined. The lower the temperature inside the box, the higher the heat shielding effect.

Table 2 shows the test results.

Table 2

Example Comparative example

8 9 10 11 12 13 14 5 6 7 8 Type of coating composition

Example 1 Example 2 Example 3 Example 4 Example 5 Example 6 Example 7 Example 1 Example 2 Example 3 Example 4 Gloss 81 81 80 82 83 81 84 82 81 84 84 Underground hiding A A A A A A A A A A A A B

96.5 94.7 95.8 96.2 95.8 25.4 94.1 95.8 96.3 94.7 93.9 Difficult surface temperature (° C) 49 41 48 40 42 55 47 63 60 68 68 麵 Back surface temperature (° C) 49 41 48 40 42 55 47 63 59 68 67 Box Internal temperature (° c) 35 30 35 30 31 41 40 50 47 55 52 Example 15 and Comparative Example 9

Acrylic resin emulsion based primer coating composition (Ales Holder GII, manufactured by Kansai Paint Co., Ltd., pigment volume concentration 62%, slate board (7 OmmX 15 OmmX 5mm), pigment volume concentration 62%, elongation at break at 20 ° C 120 %) Was applied using a doctor blade so that the dry film thickness was 1 mm, and dried at room temperature (23 ° C) for 16 hours. The obtained coating composition was applied using a doctor blade to a dry film thickness of 50 m, and dried at room temperature (23 ° C) for 14 days to obtain a test coated plate.

Examples 16 to 17

The paint composition obtained in Example 2 was applied to a slate plate (7 OmmX 15 OmmX 5 mm) using a doctor blade so that the dry film thickness became 150 m, and was applied at room temperature (23 ° C). Let dry for hours. Then, the coating composition obtained in Example 1 or Comparative Example 1 was applied on the coated surface so that the dry film thickness became 50 m, and dried at room temperature (23 ° C) for 14 days. It was a painted plate.

With respect to each of the test coated plates obtained in Examples 15 to 17 and Comparative Example 9, the gloss, the background concealing property, and the L * value were examined by the above method. Further, the heat shielding effect of each free coating film obtained by using a glass plate instead of the slate plate was examined by the above method. Table 3 shows the test results.

Table 3

In Table 3, Holder-1 G II indicates an acrylic resin emulsion-based primer coating composition (trade name “Ales Holder GII”, manufactured by Kansai Paint Co., Ltd.).

Manufacture of pigment paste Production Example 15

The following ingredients for a pigment base were placed in a 1-liter stainless steel container, and stirred for 30 minutes with a stirrer to form an aqueous pigment paste (P-9).

Water supply 100 parts

Ethylene glycol 40 parts

Dispersion resin (Note 1) 20 parts

Antifoam (Note 2) 20 parts

Thickener (Note 3) 20 parts

Titanium dioxide powder (Note 5) 120 parts

Titanium dioxide powder (Note 6) 120 parts

Production Example 16

The following ingredients for a pigment base were placed in a 1-liter stainless steel container, and stirred for 30 minutes with a stirrer to form an aqueous pigment paste (P-10).

Water supply 100 parts

Ethylene glycol 40 parts

Dispersion resin (Note 1) 20 parts

Antifoam (Note 2) 20 parts

Thickener (Note 3) 20 parts

Titanium dioxide powder (Note 5) 110 parts

Titanium dioxide powder (Note 6) 110 parts

Red pigment paste (Note 12) 10 parts

Green pigment paste (Note 13) 10 parts

Production Example 17

The following components for a pigment base were placed in a 1-liter stainless steel container, and stirred for 30 minutes with a stirrer to form an aqueous pigment paste (P11).

Water supply 100 parts

Ethylene glycol 40 parts

Antifoam (Note 2) 20 parts

Thickener (Note 3) 20 parts Red pigment paste (Note 12) 40 parts Green pigment paste (Note 13) 40 parts

Production Example 18

The following ingredients for pigment paste were placed in a 1-liter stainless steel container, and stirred for 30 minutes with a stirrer to form an aqueous pigment paste (P-12).

Water supply 100 parts

Ethylene glycol 40 parts

Dispersion resin (Note 1) 20 parts

Antifoam (Note 2) 20 parts

Thickener (Note 3) 20 parts

Titanium dioxide powder (Note 5) 120 parts

Titanium dioxide powder (Note 6) 120 parts

Perylene black pigment (Note 14) 5 parts

The above (Note 14) indicates the following.

(Note 14) Perylene black pigment: trade name “PAL I OGEN BLACK S 0084”, manufactured by BAS F.

Production Example 19

The following components for pigment paste were placed in a 1-liter stainless steel container, and stirred for 30 minutes with a stirrer to form an aqueous pigment paste (P-13).

Water supply 100 parts

Ethylene glycol 40 parts

Antifoam (Note 2) 20 parts

Thickener (Note 3) 20 parts

Carbon black pigment paste (Note 15) 20 parts

The above (Note 15) indicates the following.

(Note 15) Carbon black pigment base: NS Black C—628, trade name, manufactured by Sanyo Dyeing Co.

Production Example 20

In a 1-liter stainless steel container, put the following ingredients for pigment paste, Agitated for 30 minutes with a stirrer and dispersed to form aqueous pigment paste (P-14).

Hydroxyethyl cellulose (thickener) 0.5 咅 15

Dispersion resin (Note 16) 6. 6 咅 15

Perylene black pigment (Note 14) 33.3 parts

The above (Note 16) indicates the following.

(Note 16) Dispersing resin: trade name “BYK-190”, manufactured by Big Chemical Co., Ltd., polycarboxylic acid resin, solid content 40% by weight.

Manufacture of primer coating composition for forming thermal barrier coating

Example 18

The following components were stirred and mixed in a 1-liter stainless steel container with a stirrer for 30 minutes to obtain an aqueous primer coating composition.

Aqueous pigment paste (P-10) 350 parts

200 parts of the resin emulsion obtained in Production Example 9 (a)

2, 2, 4-trimethyl-1, 3-pen

Tandiol monoisobutylate 20 parts

Thickener (Note 17) 5 parts

Tap water 50 parts

The above (Note 17) indicates the following.

(Note 17) Thickener: Trade name “DK Sicuna I SCT-275”, manufactured by San Nopco. Examples 19 to 22 and Comparative Examples 10 to: 12

In Example 18, each undercoat paint composition was obtained with the same composition as in Example 18, except that the pigment paste and the resin emulsion were combined as shown in Table 4 below.

Table 4 also shows the L * values of the coating films formed from each of the primer coating compositions. The L * value was determined by applying each coating composition to a glass plate using a doctor blade so that the dry film thickness was 15 Om, drying at 23 ° C and 65% relative humidity for 2 days, It measured using the colorimeter similarly to and. Table 4

The resin emulsion R-3, shaku_4 and shaku-5 in Table 4 indicate the following.

R-3: Silicone resin emulsion, trade name "38% Sunmall EW1021, manufactured by San Nopco Co., with a refractive index of the coating of 1.55.

R-4: Acrylic resin emulsion, trade name "54% MK-250", manufactured by Dainippon Ink and Chemicals, Inc., with a refractive index of coating of 1.55.

R-5: Emulsion of vinyl chloride resin, trade name "45% Movinyl", manufactured by Clariant Polymer Co., Ltd. The refractive index of the coating is 1.75.

Production Example 21

The following components were stirred and mixed in a 1-liter stainless steel container with a stirrer for 30 minutes to obtain a black aqueous topcoat composition.

Aqueous pigment paste (P-14) 265 parts

Resin emulsion obtained in Production Example 9 (a) 200 parts

2,2,4-trimethyl-1,3-pen

Tandiol monoisobutylate 20 parts

Thickener (Note 17) 5 parts

Tap water 50 parts

Examples 23 to 30 and Comparative Examples 13 to 15

Each priming composition and top coating composition were applied to a slate board (10 OmmX 15 OmmX 4 mm) using the combination of Table 5 using a doctor blade, and a test coating board was prepared. Provided. The undercoat paint composition was applied to a dry film thickness of 15 Om, and the overcoat paint composition was applied to a dry film thickness of 60 m. The drying conditions were both 23 ° C (: at a relative humidity of 50%). 14 days.

For each test coated plate obtained in the above Examples 23 to 30 and Comparative Examples 13 to 15, According to the above-mentioned method, gloss, background hiding property and L * value were examined.

In addition, the heat shielding effect of each free coating film obtained using a glass plate instead of the slate plate was examined in the same manner as described above. Further, each free coating film was examined for infrared reflectance by the following method.

Infrared reflectance

For the dried free coating film, use a spectral reflectance measuring instrument (trade name “UV-310 PC”, manufactured by Shimadzu Corporation) to obtain a wavelength around 780 11111-2, 100 nm. The spectral reflectance in the infrared region was measured, and then the solar reflectance as defined in JISA 579-59 was calculated, and the result was taken as the infrared reflectance (%).

Table 5 shows the test results.

Table 5

Table 5 (continued)

The top coatings T-1, T-12 and T-13 in Table 5 are as follows. T-1: Trade name "Ales Aquadalos White", Kansai Paint Co., Ltd., Carbo Nyl group-containing acrylic resin emulsion paint, containing 100 parts of a resin component and 50 parts of a titanium dioxide pigment having an average particle diameter of 220 nm.

T-II: Trade name “Ales Aquayane Silicon Gray J”, manufactured by Kansai Paint Co., Ltd. Acrylic resin emulsion paint containing liponyl group, titanium dioxide with an average particle size of 220 nm for 100 parts of resin component Contains 50 parts of pigment and 0.8 part of carbon black.

T-1-3: ARES AQUAYANE Silicone Cream, manufactured by Kansai Paint Co., Ltd., acrylic resin emulsion paint containing liponyl group, titanium dioxide with an average particle size of 220 nm for 100 parts of resin component Contains 50 parts of pigment and 2 parts of yellow iron oxide.

Claims

The scope of the claims

1. (A) Refractive index 1. Resin component that forms a film within the range of 30 to 1.60, and

(B) a white pigment having an average primary particle size in the range of 500 to 2,000 nm and a refractive index in the range of 1.80 to 3.00

A coating composition for forming a thermal barrier coating, comprising:

2. The coating composition according to claim 1, wherein the resin component (A) contains a crosslinked acrylic resin or a non-crosslinked acrylic resin.

3. The coating composition according to claim 1, wherein the resin component (A) contains a carbonyl group-containing acrylic copolymer and a hydrazine derivative.

4. The coating composition according to claim 1, wherein the resin component (A) contains a maleimide group-containing acrylic copolymer.

5. The coating composition according to claim 1, wherein the resin component (A) contains an unsaturated fatty acid-modified acrylic resin.

6. The coating composition according to claim 1, wherein the white pigment (B) is titanium dioxide and Z or zinc oxide.

7. The coating composition according to claim 1, wherein the mixing ratio of the white pigment (B) is 10 to 140 parts by weight based on 100 parts by weight of the resin component (A).

8. The coating composition according to claim 1, further comprising a white pigment (C) having an average primary particle diameter of less than 400 nm.

9. The coating composition according to claim 8, wherein the white pigment (C) is titanium dioxide and / or zinc oxide.

10. The coating composition according to claim 8, wherein the blending ratio of the white pigment (C) is 10 to 140 parts by weight based on 100 parts by weight of the resin component (A).

11. The coating composition according to claim 8, wherein the weight ratio of the white pigment (B) to the white pigment (C) is in the range of 10/90 to 90/10.

12. The coating composition according to claim 1, further comprising a coloring pigment (D).

13. The coating composition according to claim 12, which contains, as the color pigment (D), a plurality of chromatic pigments having a complementary color relationship.

14. An overcoating composition which is the coating composition for forming a heat-shielding film according to claim 1.

15. The method according to claim 13, further comprising a colored paint (D), capable of forming a coating film having a lightness (L * value) of 20 to 70 based on the L * a * b * color system specified in JISZ 8729. The top coating composition according to any one of the preceding claims.

16. An undercoat paint composition, which is the paint composition for forming a heat-shielding film according to claim 1.

17. The undercoat coating composition according to claim 16, which can form a coating film having a lightness (L * value) of 70 to 98 based on the L * a * b * color system specified in JIS Z 8729.

18. A coating method in which a top coat composition according to claim 14 is applied in a single layer to a substrate.

19. The method according to claim 14, wherein the undercoat composition is applied to the substrate, and A coating method for applying a top coating composition.

20. A coating method in which the undercoat composition according to claim 16 is applied to an object to be coated, and the topcoat composition is applied on the coated surface.

21. The coating method according to claim 20, wherein the top coating composition is a coating composition containing a perylene pigment.