JP2007238640A - Coating composition - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a coating composition capable of suppressing adhesion of a contaminant to a coated film surface and exhibiting sufficient heat-blocking function. <P>SOLUTION: The coating composition comprises 100 pts.wt. (as solid content) coating resin, 1-200 pts.wt. infrared ray permeable powder and/or infrared ray-reflecting powder and 0.1-20 pts.wt. (expressed in terms of SiO<SB>2</SB>) silicate compound. In the coating composition, the silicate compound includes a modified silicate compound in which a tetraalkoxysilane condensation product (a) is modified by a polyhydric alcohol (b) having ≥3 hydroxy groups in one molecule and having <500 molecular weight. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a coating composition having excellent heat shielding properties.

  In recent years, in urban areas, a climate unique to cities has been created by means of artificial radiant heat discharged from concrete buildings and air conditioning. Especially in summer, the outdoor temperature rise in urban areas is remarkable, causing a problem called the heat island phenomenon. On the other hand, in buildings, the indoor temperature is often lowered by using cooling, but the heavy use of cooling not only increases the power consumption energy but also increases the outdoor temperature by exhausting from the outdoor unit. Is conducive.

  As a method for suppressing the temperature rise of a building, a method of applying a thermal barrier paint to a building exterior surface base material such as a roof, a rooftop, or an outer wall is known. As an example of such a heat-shielding paint, Patent Document 1 discloses a solar heat-shielding paint composition containing 2 to 60% by weight of a solar heat-shielding pigment having a particle size of 50 μm or less in a paint mainly composed of a vehicle and a pigment. Things are listed. Patent Document 2 uses any two or more of red, orange, yellow, green, blue, and violet pigments having a particle size of 50 μm or less having a high solar radiation reflectance in the near infrared region as the pigment. A solar heat shielding coating composition is described which is toned to black which is an achromatic color by additive color mixing.

JP-A-1-121371 JP-A-4-255769

  However, in the thermal barrier coating described in the patent document as described above, resistance to contaminants is not taken into consideration. Particularly recently, oily pollutants are floating in the atmosphere due to exhaust gases from automobiles and the like in the city center and suburbs. These pollutants have a very high ability to absorb infrared rays in sunlight. For this reason, if the contaminants adhere to the surface of the coating film of the thermal barrier paint, it acts as a heat storage field, which may impair the original thermal barrier function of the thermal barrier paint and cause an increase in the temperature of the coating film.

  The present invention has been made in view of such problems, and can obtain a coating composition that can suppress the adhesion of contaminants to the surface of the coating film and can exhibit a sufficient heat shielding function. It is intended.

  As a result of intensive studies in view of the problems of the prior art as described above, the present inventors have found that a coating resin, an infrared transmitting powder and / or an infrared reflecting powder, and a specific modified silicate are used. The present inventors have conceived a coating composition having a main component and completed the present invention.

That is, the coating composition of the present invention has the following characteristics.
1. 1 to 200 parts by weight of the infrared transmitting powder and / or infrared reflecting powder and 0.1 to 20 parts by weight of the silicate compound in terms of SiO ₂ with respect to 100 parts by weight of the solid content of the coating resin, As a silicate compound,
The tetraalkoxysilane condensate (a) contains a modified silicate compound modified with a polyhydric alcohol (b) having three or more hydroxyl groups in one molecule and a molecular weight of less than 500. .
2. 1. The modified silicate compound is modified at a ratio of 0.01 to 1 mol of the polyhydric alcohol (b) with respect to 1 mol of the tetraalkoxysilane condensate (a). The coating composition as described.
3. The modified silicate compound is a mixture of two or more alkoxyl groups having different carbon numbers. Or 2. The coating composition as described in 2.

  In the coating composition of this invention, adhesion of the contaminant to the coating-film surface can be suppressed, and sufficient heat-shielding function can be exhibited.

  Hereinafter, the best mode for carrying out the present invention will be described in detail.

  The coating composition of the present invention comprises a coating resin, an infrared transmitting powder and / or an infrared reflecting powder, and a modified silicate compound as main components.

  Examples of the coating resin include acrylic resins, polyester resins, polyether resins, polyurethane resins, acrylic silicon resins, fluororesins, vinyl acetate resins, epoxy resins, and composites thereof. These can be used alone or in combination of two or more. Examples of the form of the coating resin include solvent-soluble resins, non-water dispersible resins, water-soluble resins, water-dispersible resins, and solvent-free resins.

  Among these, the solvent-soluble resin and / or the non-aqueous dispersible resin is a non-aqueous solvent as a medium, and 50% by weight or more (preferably 60% by weight or more) of the total solvent is aliphatic carbonized. A so-called weak solvent resin which is hydrogen is preferred. Such weak solvent resins are less toxic and have higher work safety compared to strong solvent resins that use aromatic hydrocarbon solvents as the main solvent, and when applied to existing coatings. It has a feature that the occurrence of lifting can be suppressed. Examples of the aliphatic hydrocarbon include n-hexane, n-pentane, n-octane, n-nonane, n-decane, n-undecane, n-dodecane, and the like. In addition, terpine oil, mineral spirit, etc. Other aliphatic hydrocarbon solvents can also be used. In particular, those which do not contain toluene and xylene and correspond to the second petroleum having a flash point of 21 ° C. or higher are preferable in terms of safety and health. In the present invention, when such a weak solvent type resin is used as a coating resin, a particularly excellent effect can be obtained.

  The coating resin in the present invention may have crosslinking reactivity. When the coating resin is a cross-linking resin, the strength, water resistance, weather resistance, adhesion and the like of the coating film can be improved. The cross-linking reaction type resin may be one that causes a cross-linking reaction by itself or one that causes a cross-linking reaction by a cross-linking agent that is separately mixed. Such crosslinking reactivity includes, for example, hydroxyl group and isocyanate group, carbonyl group and hydrazide group, epoxy group and amino group, aldo group and semicarbazide group, keto group and semicarbazide group, alkoxyl group, carboxyl group and metal ion, carboxyl group It can be imparted by combining a reactive functional group such as a group and a carbodiimide group, a carboxyl group and an epoxy group, a carboxyl group and an aziridine group, a carboxyl group and an oxazoline group. Among these, a hydroxyl group-isocyanate group crosslinking reaction type resin is preferable.

  The glass transition temperature of the coating resin in the present invention is usually about -20 to 80 ° C (preferably -10 to 60 ° C).

  The composition of the present invention contains an infrared reflecting powder and / or an infrared transmitting powder. In this invention, it becomes possible to suppress the thermal storage of the coating film by sunlight, coloring a coating material in a desired color by containing this component.

Specifically, the infrared reflective powder includes, for example, aluminum flakes, titanium oxide, barium sulfate, zinc oxide, calcium carbonate, silicon oxide, magnesium oxide, zirconium oxide, yttrium oxide, indium oxide, alumina, and iron chromium composite oxide. Products, manganese bismuth composite oxide, manganese yttrium composite oxide, and the like.
On the other hand, examples of the infrared transmitting powder include perylene pigment, azo pigment, chrome lead, petal, vermilion, titanium red, cadmium red, quinacridone red, isoindolinone, benzimidazolone, phthalocyanine green, phthalocyanine blue, and cobalt. Examples thereof include blue, indanthrene blue, ultramarine blue, and bitumen, and one or more of these can be used. In general, there is a limit to the hue that can be expressed only by using an infrared reflective powder, but it is possible to form coating films of various hues by appropriately combining these infrared transparent powders. .

  In the composition of the present invention, a coating film having an infrared reflectance of 20% or more (preferably 40% or more, more preferably 55% or more) by containing an infrared reflecting powder and / or an infrared transmitting powder, or an infrared ray A coating film having a transmittance of 20% or more (preferably 40% or more, more preferably 55% or more) can be formed. In addition, the infrared reflectance said here is a value obtained by measuring the spectral reflectance with respect to the light of wavelength 800-2100nm, and calculating the average value. The infrared transmittance is a value obtained by measuring a spectral transmittance for light having a wavelength of 800 to 2100 nm and calculating an average value thereof.

  The mixing amount of the infrared reflecting powder and / or infrared transmitting powder (total amount of both components) is usually 1 to 200 parts by weight, preferably 2 to 100 parts by weight, based on 100 parts by weight of the solid content of the coating resin. Part. Within such a range, the paint can be toned in a desired color, and advantageous effects can be obtained in terms of preventing cracking of the coating film.

  In the coating composition of the present invention, a tetraalkoxysilane condensate (a) (hereinafter referred to as “component (a)”) as a silicate compound has three or more hydroxyl groups in one molecule and a molecular weight of less than 500. It contains a modified silicate compound modified with a monohydric alcohol (b) (hereinafter referred to as “component (b)”). In the present invention, the hydrophilicity of the coating film surface is increased by the action of such a modified silicate compound, the adhesion of contaminants to the coating film surface can be suppressed, and thus the thermal barrier performance of the coating film can be sufficiently exhibited. it can.

  Examples of the component (a) include tetramethoxysilane, tetraethoxysilane, tetra n-propoxysilane, tetraisopropoxysilane, tetra n-butoxysilane, tetraisobutoxysilane, tetrasec-butoxysilane, and tetra t-butoxysilane. , Tetraphenoxysilane, monoethoxytrimethoxysilane, monobutoxytrimethoxysilane, monopentoxytrimethoxysilane, monohetoxytrimethoxysilane, dimethoxydiethoxysilane, dimethoxydibutoxysilane and the like. Among these, a tetramethoxysilane condensate and a tetraethoxysilane condensate are advantageous in terms of expressing stain resistance. In addition, the average condensation degree of (a) component is 1-100 normally, Preferably it is about 4-20.

In the present invention, a polymerized silicate compound can be obtained by modifying the component (a) with the component (b). Such a modified silicate has a high orientation on the coating film surface, and works extremely effectively to improve the stain resistance, particularly to improve the stain resistance at the initial stage of coating film formation.
As the component (b), a polyhydric alcohol having 3 or more hydroxyl groups in one molecule and having a molecular weight of less than 500 can be used. Examples of such component (b) include glycerin, trimethylolpropane, 1,2,4-butanetriol, 2,3,5-hexanetriol, 1,2,6-hexanetriol, pentaerythritol, dipenta. Examples include erythritol. Also, among polyol compounds such as polyester polyol, polyether polyol and polyacryl polyol, those having a molecular weight satisfying the above conditions can be used.

  As the component (b) in the present invention, a compound having three hydroxyl groups in one molecule is particularly suitable, and a compound having a molecular weight of 200 or less (more preferably 150 or less) is preferred. In particular, glycerin is preferred in the present invention. In such a modified silicate modified with the component (b), since the hydroxyl group is close in the component (b), the hydroxyl group tends to remain due to steric hindrance during the reaction with the component (a). This hydroxyl group is considered to be advantageous in the effect of improving stain resistance, adhesion, compatibility with other components, and the like.

  In order to modify the component (a) with the component (b), a transesterification reaction may be used. When performing the transesterification reaction, a transesterification catalyst may be used as necessary. As such a transesterification catalyst, an organic tin compound, an organic titanate compound, a phosphoric acid compound, an acid anhydride, amines, etc. can be used, for example. Moreover, at the time of transesterification, it can also heat (usually about 50-150 degreeC). If necessary, the reaction can be carried out in the presence of a solvent.

  The modification ratio of the component (a) and the component (b) is such that the component (b) is in the range of 0.01 to 1 mol (preferably 0.05 to 0.3 mol) with respect to 1 mol of the component (a). It is desirable to do. By carrying out the modification at such a ratio, sufficient stain resistance can be obtained. If this ratio is too small, it becomes difficult to obtain the effect of improving the stain resistance. If it is too high, problems such as gelation may occur during modification.

  As the modified silicate compound in the present invention, a compound in which two or more kinds of alkoxyl groups having different carbon numbers are mixed is suitable. If the modified silicate compound is such a compound, the antifouling effect can be further enhanced. Examples of the combination of alkoxyl groups having different carbon numbers include a combination of a methoxy group having 1 carbon atom and an alkoxyl group having 2 to 12 carbon atoms, or a combination of an ethoxy group having 2 carbon atoms and an alkoxyl group having 3 to 12 carbon atoms. From the viewpoint of developing stain resistance at the initial stage of coating film formation. Among these, it is a combination of a methoxy group and an alkoxyl group having 2 to 12 carbon atoms (preferably 3 to 10 carbon atoms), and more than 5 equivalent% (preferably 5 to 50 equivalent%) of the total alkoxyl group. ) Is an alkoxyl group having 2 to 12 carbon atoms, or a combination of an ethoxy group and an alkoxyl group having 3 to 12 carbon atoms (preferably 3 to 10 carbon atoms). Of these, those in which 5 equivalent% or more (preferably 5 to 50 equivalent%) is an alkoxyl group having 3 to 12 carbon atoms are particularly suitable. In the case of having a branched alkoxyl group as an alkoxyl group having 3 to 12 carbon atoms (preferably 3 to 10 carbon atoms), it is particularly preferable in terms of surface hydrophilicity and crack resistance of the coating film.

  Specifically, in order to obtain a modified silicate having a methoxy group and an alkoxyl group having 2 to 12 carbon atoms, it can be produced by the method exemplified below.

(1) General formula Si (OR ¹ ) (OR ² ) (OR ³ ) (OR ⁴ )
(Wherein R ^{1 to} R ⁴ are a mixture of a methyl group and an alkyl group having 2 to 12 carbon atoms), an average condensation degree of 1 to 200 (preferably 2 to 100). ) To condense. The condensation method is a known method. In this case, other tetraalkoxysilanes can be mixed and condensed during the condensation.
Specific examples of the compound represented by the above general formula include, for example, monoethoxytrimethoxysilane, monobutoxytrimethoxysilane, monoisobutoxytrimethoxysilane, monopentoxytrimethoxysilane, monohexoxytrimethoxysilane, dimethoxydisilane. Examples include ethoxysilane, dimethoxydibutoxysilane, and the like, and condensates thereof.

(2) The tetramethoxysilane condensate is reacted with a monoalcohol having 2 to 12 carbon atoms to transesterify 5 equivalent% or more (preferably 5 to 50 equivalent%) of the methoxy group in the tetramethoxysilane condensate. Examples of the alcohol having 2 to 12 carbon atoms in this method include ethanol, n-propanol, isopropyl alcohol, n-butyl alcohol, isobutyl alcohol, sec-butyl alcohol, t-butyl alcohol, n-amyl alcohol, and n-hexyl. Examples include alcohol, 2-ethyl-1-hexanol, n-heptanol, isoheptyl alcohol, n-octanol, 2-octanol, n-nonanol, n-decanol, n-undecyl alcohol, and n-dodecyl alcohol.

  In addition, in order to obtain a modified silicate having an ethoxy group and an alkoxyl group having 3 to 12 carbon atoms, instead of the methods (1) and (2), the following (1 ′) and (2 ′) are used, respectively. The method shown may be adopted.

(1 ′) General formula Si (OR ¹ ) (OR ² ) (OR ³ ) (OR ⁴ )
(Wherein R ^{1 to} R ⁴ are a mixture of an ethyl group and an alkyl group having 3 to 12 carbon atoms), an average condensation degree of 1 to 200 (preferably 2 to 100). ) To condense.

(2 ') The tetraethoxysilane condensate is reacted with a monoalcohol having 3 to 12 carbon atoms to transesterify 5 equivalent% or more (preferably 5 to 50 equivalent%) of the ethoxy group in the tetramethoxysilane condensate.

  According to the above method, a modified silicate in which alkoxy groups having different carbon numbers are mixed can be obtained, but the timing of the reaction is not particularly limited, and before or after the reaction with the component (b) or during the reaction. There may be.

  In the present invention, a silicate compound other than the above-described modified silicate compound may be used in combination, but 80% by weight or more (preferably 95% by weight or more) of the entire silicate compound may be composed of the above-described modified silicate compound. desirable.

  In the present invention, by using a specific modified silicate as described above, it is possible to obtain a sufficient hydrophilizing function and hence a stain resistance effect even if the amount of the silicate compound is small compared with the prior art. Therefore, it is advantageous also in terms of followability of the formed coating film to the ground, crack resistance, and the like. That is, according to the present invention, it is possible to relatively reduce the amount of the silicate compound, and it is possible to design a paint that is extremely useful in practice.

The mixing ratio of the silicate compound, based on 100 parts by weight of the solid content of the coating resin, 0.1 to 20 parts by weight in terms of SiO ₂ (preferably 0.3 to 10 parts by weight, more preferably 0.5 to 5 It may be set within the range of (weight part). When the mixing ratio of the silicate compound is less than 0.1 parts by weight, the coating film is not imparted with hydrophilicity, so that the stain resistance is insufficient. On the other hand, when it exceeds 20 parts by weight, the followability of the formed coating film to the ground becomes insufficient, and cracks and the like are likely to occur.

The SiO ₂ conversion in the present invention means the weight remaining as silica (SiO ₂ ) when a compound having a Si—O bond such as alkoxysilane or silicate is completely hydrolyzed and then baked at 900 ° C. Expressed in minutes.
In general, alkoxysilanes and silicates have a property of reacting with water to cause a hydrolysis reaction to form silanol, and further causing a condensation reaction between silanols or between silanol and alkoxy. When this reaction is performed to the ultimate, silica (SiO ₂ ) is obtained. These reactions are RO (Si (OR) ₂ O) _n R + (n + 1) H ₂ O → nSiO ₂ + (2n + 2) ROH
(R represents an alkyl group. N is an integer.)
It is expressed by the reaction formula. The SiO ₂ conversion in the present invention is the conversion of the amount of the remaining silica component based on this reaction formula.

  In the composition of the present invention, an amine compound can be mixed in addition to the above components. By admixing such an amine compound, it is possible to enhance the adhesion when the composition of the present invention is applied (recoated). Furthermore, the amine compound contributes to improvement of physical properties such as stain resistance and curability by interaction with the modified silicate compound.

  Examples of amine compounds include ethylamine, dimethylamine, diamylamine, cyclohexylamine, aniline, hexamethylenediamine, ethylenediamine, trimethylamine, triethylamine, tripropylamine, tributylamine, triphenylamine, dimethyldodecylamine, dimethylbenzylamine, dimethylcyclohexyl. In addition to amine, pyridine, morpholine, etc., ethanolamine, diethanolamine, dimethylethanolamine, N-methyldiethanolamine, triethanolamine and ethylphenylethanolamine-containing amine compounds such as triethylenediamine ([2,2,2] dia Abicyclooctane), tetramethylethylenediamine, pentamethyldiethylenetriamine, etc. Alkyl group-containing amine compound, aminomethyl triethoxysilane, diamino methyl diethoxy silane, .gamma.-amino isobutyl trimethoxy silane, alkoxysilyl group-containing amine compounds such as .gamma.-aminopropyl methyl diethoxy silane, and the like.

  In the present invention, as the amine compound, bis (2,2,6-tetramethyl-4-piperidyl) sebacate, bis (1,2,2,6,6-pentamethyl-4-piperidyl) sebacate, bis (1- Octoxy-2,2,6,6-tetramethyl-4-piperidyl) sebacate, 2- (3,5-di-t-butyl-4-hydroxybenzyl) -2-n-butylmalonate bis (1,2 , 2,6,6-pentamethyl-4-piperidyl), tetrakis (2,2,6,6-tetramethyl-4-piperidyl) -1,2,3,4-butanetetracarboxylate, tetrakis (1,2 , 2,6,6-pentamethyl-4-piperidyl) -1,2,3,4-butanetetracarboxylate and the like can also be used.

  As the amine compound, an amine compound having a base dissociation constant pKb of 3 or more and 11 or less (preferably 4 or more and 8 or less) is particularly preferable. By using such a compound, physical properties such as recoatability, stain resistance and curability can be further enhanced.

  The mixing ratio of the amine compound is usually 0.01 to 20 parts by weight, preferably 0.02 to 5 parts by weight with respect to 100 parts by weight of the solid content of the coating resin. Within such a range, sufficient effects can be obtained in recoatability, stain resistance, curability, etc., and this is also preferable in terms of ensuring pot life.

  Various additives that can be usually used for paints can be blended in the composition of the present invention. Examples of such additives include curing agents, plasticizers, preservatives, antifungal agents, antialgae agents, antifoaming agents, leveling agents, pigment dispersants, antisettling agents, anti-sagging agents, catalysts, curing accelerators, Examples include dehydrating agents, matting agents, ultraviolet absorbers, and antioxidants.

The composition of the present invention is not particularly limited as long as each of the above components is a constituent component, but usually includes a coating resin, an infrared transmitting powder and / or an infrared reflecting powder. It is desirable to make a two-component paint comprising a main agent and a curing agent containing a modified silicate compound. Such a form is preferable in terms of ensuring the stability of the coating material and exhibiting antifouling performance.
When the coating resin has a crosslinking reactive group and a crosslinking agent capable of reacting with the reactive group is used, the crosslinking agent may be mixed with a curing agent. Specifically, when the coating resin has a hydroxyl group, an isocyanate compound can be mixed with the curing agent.

  The composition of the present invention can be used for surface finishing of building exterior surfaces such as roofs, rooftops, and outer walls. The base material of the exterior surface is not particularly limited, and examples thereof include concrete, mortar, metal, plastic, or various boards such as a slate plate, an extruded plate, and a siding board. The composition of the present invention can be applied to an existing building having such a substrate. As a coating method, methods such as brush coating, spray coating, and roller coating can be appropriately employed. Various boards can be pre-coated at a factory or the like in advance.

  The aforementioned exterior surface base material may have some surface treatment layer. Such a surface treatment layer can be formed of a surface treatment material generally called a sealer, a surfacer, a filler or the like. In the present invention, a surface treatment material containing infrared reflective powder is suitable. By using such a surface treatment material, heat storage of the exterior surface base material can be suppressed, and the heat shielding effect can be enhanced.

  Examples are given below to clarify the features of the present invention.

(Production of modified silicate compound)
・ Modified silicate (1)
N-Butyl with respect to 100 parts by weight of methyl silicate (hereinafter referred to as “tetraalkoxysilane condensate (1)”) having a weight average molecular weight of 1000, an average degree of condensation of about 8, a non-volatile content of 100%, and a silica residual ratio of 56% by weight. 52 parts by weight of alcohol and 0.03 part by weight of dibutyltin dilaurate were added as a catalyst. After mixing, a demethanol reaction was performed at 75 ° C. for 8 hours to synthesize a tetraalkoxysilane condensate (2). The transesterification rate of this tetraalkoxysilane condensate (2) (ratio of n-butoxy groups to all alkoxyl groups) was 38 equivalent%, and the residual silica ratio obtained by firing at 900 ° C. was 43% by weight. It was.

  Next, 0.92 parts by weight of glycerin and 0.5 parts by weight of dibutyltin dilaurate are added to 100 parts by weight of the tetraalkoxysilane condensate (2) obtained by the above method. A time-demethanol reaction was performed to synthesize modified silicate (1). In addition, the molar ratio of the tetraalkoxysilane condensate (2) and glycerin in this reaction was 1: 0.1, and the remaining silica ratio obtained by baking at 900 ° C. was 42% by weight. .

・ Modified silicate (2)
To 100 parts by weight of the tetraalkoxysilane condensate (2), 1.84 parts by weight of glycerin and 1 part by weight of dibutyltin dilaurate are added, mixed, and then subjected to a demethanol reaction at 75 ° C. for 8 hours to obtain a modified silicate (2) Was synthesized. In addition, the molar ratio of the tetraalkoxysilane condensate (2) and glycerin in this reaction was 1: 0.2, and the residual silica ratio obtained by baking at 900 ° C. was 42% by weight. .

・ Modified silicate (3)
To 100 parts by weight of the tetraalkoxysilane condensate (1), 52 parts by weight of isobutyl alcohol and 0.03 part by weight of dibutyltin dilaurate as a catalyst were added, mixed and then subjected to a demethanol reaction at 75 ° C. for 8 hours. An alkoxysilane condensate (3) was synthesized. The transesterification rate of this tetraalkoxysilane condensate (3) (ratio of isobutoxy groups to all alkoxyl groups) was 38 equivalent%, and the residual silica ratio obtained by firing at 900 ° C. was 43% by weight.

  Next, 0.92 parts by weight of glycerin and 0.5 parts by weight of dibutyltin dilaurate are added to 100 parts by weight of the tetraalkoxysilane condensate (3) obtained by the above method. A time-demethanol reaction was performed to synthesize modified silicate (3). In addition, the molar ratio of the tetraalkoxysilane condensate (3) and glycerin in this reaction was 1: 0.1, and the remaining silica ratio obtained by firing at 900 ° C. was 42% by weight. .

(Manufacture of main agent)
・ Main agent (1)
Non-aqueous dispersion type acrylic polyol (hydroxyl value 50KOHmg / g, weight average molecular weight 80,000, glass transition temperature 38 ° C, solid content 50% by weight, medium: mineral spirit, aliphatic hydrocarbon 70% by weight) 200 parts by weight phthalocyanine 8 parts by weight of green, 3 parts by weight of phthalocyanine blue, 5 parts by weight of perylene red, 4 parts by weight of benzimidazolone yellow, 80 parts by weight of mineral spirit, 4 parts by weight of amide wax-based thickener, 1 part by weight of silicone-based antifoaming agent The main agent (1) was produced by uniformly mixing and stirring by a conventional method.

・ Main agent (2)
Non-aqueous dispersion type acrylic polyol (hydroxyl value 50KOHmg / g, weight average molecular weight 80,000, glass transition temperature 38 ° C, solid content 50% by weight, medium: mineral spirit, aliphatic hydrocarbon 70% by weight) 200 parts by weight phthalocyanine 8 parts by weight of green, 3 parts by weight of phthalocyanine blue, 5 parts by weight of perylene red, 4 parts by weight of benzimidazolone yellow, bis (1,2,2,6,6-pentamethyl-4-piperidyl) sebacate (molecular weight 508, pKb5. 5) 2 parts by weight, mineral spirits 80 parts by weight, amide wax thickener 4 parts by weight and silicone antifoam 1 part by weight are uniformly mixed and stirred in a conventional manner to produce the main agent (2). did.

・ Main agent (3)
Non-aqueous dispersion type acrylic polyol (hydroxyl value 50KOHmg / g, weight average molecular weight 80,000, glass transition temperature 38 ° C, solid content 50% by weight, medium: mineral spirit, aliphatic hydrocarbon 70% by weight) 200 parts by weight phthalocyanine Main agent (3) was produced by uniformly mixing and stirring 20 parts by weight of green, 80 parts by weight of mineral spirit, 4 parts by weight of amide wax thickener, and 1 part by weight of silicone-based antifoaming agent in a conventional manner. .

・ Main agent (4)
Non-aqueous dispersion type acrylic polyol (hydroxyl value 50KOHmg / g, weight average molecular weight 80,000, glass transition temperature 38 ° C, solid content 50% by weight, medium: mineral spirit, aliphatic hydrocarbon 70% by weight) 200 parts by weight phthalocyanine The main agent (4) was produced by uniformly mixing and stirring 20 parts by weight of blue, 80 parts by weight of mineral spirit, 4 parts by weight of an amide wax thickener and 1 part by weight of a silicone-based antifoaming agent in a conventional manner. .

・ Main agent (5)
Non-water-dispersed acrylic polyol (hydroxyl value 50KOHmg / g, weight average molecular weight 80000, glass transition temperature 38 ° C, solid content 50% by weight, medium: mineral spirit, aliphatic hydrocarbon 70% by weight) The main agent (5) was produced by uniformly mixing and stirring 20 parts by weight of black, 80 parts by weight of mineral spirit, 4 parts by weight of an amide wax thickener, and 1 part by weight of a silicone-based antifoaming agent. .

(Manufacture of curing agent)
・ Curing agent (1)
40 parts by weight of Solvesso 100 (manufactured by Exxon Chemical) and 20 parts by weight of the modified silicate compound (1) are uniformly added to 40 parts by weight of polyisocyanate containing isocyanurate structure (non-volatile content: 100% by weight, NCO content: 21% by weight). The curing agent (1) was produced by mixing.

・ Curing agent (2)
40 parts by weight of Solvesso 100 (manufactured by Exxon Chemical) and 20 parts by weight of the modified silicate compound (2) are uniformly added to 40 parts by weight of the polyisocyanate containing isocyanurate structure (non-volatile content: 100% by weight, NCO content: 21% by weight). The curing agent (2) was produced by mixing.

・ Curing agent (3)
For 40 parts by weight of polyisocyanate containing isocyanurate structure (non-volatile content: 100% by weight, NCO content: 21% by weight), 40 parts by weight of Solvesso 100 (manufactured by Exxon Chemical) and 20 parts by weight of the modified silicate compound (3) The curing agent (3) was produced by mixing.

・ Curing agent (4)
40 parts by weight of Solvesso 100 (manufactured by Exxon Chemical Co.) and 20 parts by weight of tetraalkoxysilane condensate (2) with respect to 40 parts by weight of polyisocyanate containing isocyanurate structure (non-volatile content: 100% by weight, NCO content: 21% by weight) The curing agent (4) was produced by mixing uniformly.

・ Curing agent (5)
10 parts by weight of Solvesso 100 (manufactured by Exxon Chemical) and 50 parts by weight of the tetraalkoxysilane condensate (2) with respect to 40 parts by weight of polyisocyanate containing isocyanurate structure (non-volatile content: 100% by weight, NCO content: 21% by weight) The curing agent (5) was produced by mixing uniformly.

・ Curing agent (6)
45 parts by weight of Solvesso 100 (manufactured by Exxon Chemical Co.) and 15 parts by weight of tetraalkoxysilane condensate (1) with respect to 40 parts by weight of polyisocyanate containing isocyanurate structure (non-volatile content: 100% by weight, NCO content: 21% by weight) The curing agent (6) was produced by mixing uniformly.

・ Curing agent (7)
Curing agent (7) is obtained by uniformly mixing 60 parts by weight of Solvesso 100 (manufactured by Exxon Chemical Co.) with 40 parts by weight of polyisocyanate containing isocyanurate structure (non-volatile content: 100% by weight, NCO content: 21% by weight). Manufactured.

(Manufacture of paint)
・ Paint A
The main agent (1) and the curing agent (1) produced by the above method were uniformly mixed at a weight ratio of 86:14 to obtain a coating material A. The mixing ratio of the modified silicate compound in the coating material A was 4.2 parts by weight in terms of SiO _{2 with} respect to 100 parts by weight of the resin solid content. Moreover, when the infrared rays transmittance was measured using the spectrophotometer (Shimadzu "UV-3100") about the dry paint film (40 micrometers) of the coating material A, the value was 69%.

・ Paint B
The base agent (1) and curing agent (2) produced by the above method were uniformly mixed at a weight ratio of 86:14 to obtain a coating material B. The mixing ratio of the modified silicate compound in the coating material B was 4.2 parts by weight in terms of SiO _{2 with} respect to 100 parts by weight of the resin solid content. Further, the infrared transmittance of the paint B was 69%.

・ Paint C
The base agent (1) and the curing agent (3) produced by the above method were uniformly mixed at a weight ratio of 86:14 to obtain paint C. The mixing ratio of the modified silicate compound in the coating material C was 4.2 parts by weight in terms of SiO _{2 with} respect to 100 parts by weight of the resin solid content. Further, the infrared transmittance of the paint C was 69%.

・ Paint D
The base agent (2) and the curing agent (1) produced by the above method were uniformly mixed at a weight ratio of 86:14 to obtain a coating material D. The mixing ratio of the modified silicate compound in the coating material D was 4.2 parts by weight in terms of SiO _{2 with} respect to 100 parts by weight of the resin solid content. Further, the infrared transmittance of the coating material D was 69%.

・ Paint E
The main agent (3) and the curing agent (1) produced by the above method were uniformly mixed at a weight ratio of 86:14 to obtain paint E. The mixing ratio of the modified silicate compound in the coating material E was 4.2 parts by weight in terms of SiO _{2 with} respect to 100 parts by weight of the resin solid content. Further, the infrared transmittance of the paint E was 65%.

・ Paint F
The base agent (4) and the curing agent (1) produced by the above method were uniformly mixed at a weight ratio of 86:14 to obtain paint F. The mixing ratio of the silicate compound in the coating material F was 4.2 parts by weight in terms of SiO _{2 with} respect to 100 parts by weight of the resin solid content. The infrared transmittance of the paint F was 72%.

・ Paint G
The main agent (1) and the curing agent (4) produced by the above method were uniformly mixed at a weight ratio of 86:14 to obtain a paint G. The mixing ratio of the silicate compound in the coating material G was 4.3 parts by weight in terms of SiO _{2 with} respect to 100 parts by weight of the resin solid content. The infrared transmittance of paint G was 69%.

・ Paint H
The main agent (1) and the curing agent (5) produced by the above method were uniformly mixed at a weight ratio of 86:14 to obtain paint H. The mixing ratio of the silicate compound in the coating material H was 10.7 parts by weight in terms of SiO _{2 with} respect to 100 parts by weight of the resin solid content. Further, the infrared transmittance of the paint H was 69%.

・ Paint I
The main agent (5) and the curing agent (1) produced by the above method were uniformly mixed at a weight ratio of 86:14 to obtain paint I. The mixing ratio of the silicate compound in the coating material I was 4.2 parts by weight in terms of SiO _{2 with} respect to 100 parts by weight of the resin solid content. Further, the infrared transmittance of the paint I was 2%.

・ Paint J
The base agent (1) and the curing agent (6) produced by the above method were uniformly mixed at a weight ratio of 86:14 to obtain a paint J. The mixing ratio of the silicate compound in the coating material J was 4.3 parts by weight in terms of SiO _{2 with} respect to 100 parts by weight of the resin solid content. The infrared transmittance of the paint J was 69%.

・ Paint K
The main agent (1) and curing agent (7) produced by the above method were uniformly mixed at a weight ratio of 86:14 to obtain paint K. The infrared transmittance of the paint K was 69%.

(Test method)
・ Heat insulation test An aluminum base plate was coated with an epoxy-based primer to a dry film thickness of 30 μm, dried in standard conditions (temperature 23 ° C., relative humidity 50%) for 8 hours, and then subjected to the above method. Each of the obtained paints was applied to a dry film thickness of 40 μm and dried for 7 days in a standard state to prepare a test specimen. The coating film of the test specimen was irradiated with an infrared lamp from a distance of 20 cm, and the test specimen back surface temperature when the temperature rise reached equilibrium was measured.
Further, after preparing a test specimen by the same method, a 15 wt% carbon black aqueous dispersion paste was uniformly sprayed on the entire coating film of the test specimen and left in a thermostatic chamber at 50 ° C. for 2 hours. Thereafter, ultrasonic cleaning was performed for 10 minutes using a sonicator, and the mixture was left in a standard state for 24 hours. An infrared lamp was irradiated from a distance of 20 cm to the coating film of the test body subjected to the above treatment, and the back surface temperature of the test body when the temperature rise reached equilibrium was measured.
The evaluation criteria for the heat shielding test were ○ when the back surface temperature of the specimen was less than 70 ° C, Δ when it was 70 ° C or more and less than 80 ° C, and × when it was 80 ° C or more.

・ Exposure test An aluminum base plate was coated with an epoxy-based primer to a dry film thickness of 30 μm, dried in a standard state for 8 hours, and then each paint obtained by the above method had a dry film thickness of 40 μm. A test specimen was prepared by coating the film and drying it under standard conditions for 7 days.
This test specimen is placed under the corrugated plastic corrugated sheet (installed so that the rainwater flowing from the coral contacts the paint film surface of the specimen) and exposed outdoors, one week and one month after the exposure. The contact angle of the coating film surface at the time of was measured. The contact angle was measured with a CA-A contact angle measuring device manufactured by Kyowa Interface Science Co., Ltd.

・ Cooling cycle test After coating the epoxy base coat on a 300 mm x 150 mm x 6 mm slate plate so that the dry film thickness is 30 μm, and drying for 8 hours in a standard state, the waterproof type composite specified in JIS A6909 is used. The layer finish coating material E main material was applied so as to have a dry film thickness of 2 mm, and dried in a standard state for 24 hours. Subsequently, each coating material obtained by the above method was applied so that the dry film thickness was 40 μm, and dried in a standard state for 7 days to prepare a test specimen.
About the test body obtained by the above method, after performing a total of 10 cycles of hot and cold repeated tests in which water immersion (23 ° C.) 18 hours → −20 ° C. 3 hours → 80 ° C. 3 hours is one cycle, The presence or absence of cracks in the film was confirmed visually. In the evaluation, “◯” indicates that no crack was generated, “Δ” indicates that the crack was slightly generated, and “X” indicates that the crack was clearly generated.

(Test results)
The test results are shown in Table 1. As a result of carrying out the above tests, the paints A to F were generally excellent in the heat shielding performance, the hydrophilic property of the coating film surface, and the followability to the ground.

Claims (3)

1 to 200 parts by weight of the infrared transmitting powder and / or infrared reflecting powder and 0.1 to 20 parts by weight of the silicate compound in terms of SiO ₂ with respect to 100 parts by weight of the solid content of the coating resin, As a silicate compound,
The tetraalkoxysilane condensate (a) contains a modified silicate compound modified with a polyhydric alcohol (b) having three or more hydroxyl groups in one molecule and a molecular weight of less than 500. .   2. The modified silicate compound is modified at a ratio of 0.01 to 1 mol of the polyhydric alcohol (b) with respect to 1 mol of the tetraalkoxysilane condensate (a). The coating composition as described.   The coating composition according to claim 1 or 2, wherein the modified silicate compound is a mixture of two or more alkoxyl groups having different carbon numbers.