JP5086650B2 - Paint composition - Google Patents

Description

  The present invention relates to a coating composition having excellent stain resistance.

  Buildings, civil engineering structures, and the like are painted with various paints for the purpose of protecting the frame and improving aesthetics. However, in recent years, in urban areas and the like, oily pollutants and the like are floating in the atmosphere due to exhaust gas from automobiles and the like, and the surface of the coating film is easily contaminated by these pollutants.

On the other hand, various techniques for blending a silicate compound with a paint have been proposed as techniques for improving the stain resistance. For example, WO94 / 06870 (Patent Document 1) discloses a top coating composition obtained by mixing an organic coating composition with a silicate compound such as methyl silicate. In the paint described in Patent Document 1, the silicate compound imparts hydrophilicity to the surface of the coating film, and stain resistance is expressed by the action that the contaminants attached to the coating film are washed away during rain.
However, the paint described in Patent Document 1 has a problem that, for example, hydrophilicity is not expressed at the initial stage of coating film formation, and contaminants are easily attached. It is also difficult to ensure practical performance in terms of mixing stability, pot life, etc. when a silicate compound is blended in the paint.

Japanese Patent Laid-Open No. 11-209690 (Patent Document 2) discloses a technique for suppressing the adhesion and deposition of contaminants by increasing the initial hydrophilicity of a coating film. The coating composition of patent document 2 consists of a silicate compound in which a methyl group and an organic group having 1 to 10 carbon atoms are mixed, and a coating resin. Specifically, in the examples of the patent document, a silicate compound in which a methyl group and an ethyl group are mixed is described.
However, in order to obtain a sufficient stain resistance effect in the coating composition of Patent Document 2, it is necessary to add a considerable amount of a silicate compound. That is, in the coating composition of Patent Document 2, a certain effect can be obtained by adding a silicate compound so as to meet the stain resistance, but on the other hand, the followability of the formed coating film to the ground, crack resistance, etc. There is a risk that this may cause problems. Furthermore, since the silicate compound is generally an expensive material, the amount of the silicate compound becomes a factor that presses the cost.

WO94 / 06870 Publication JP-A-11-209690

  The present invention has been made in view of such circumstances, and in coatings containing a silicate compound, it exhibits sufficient stain resistance and improves the followability of the formed coating film to the ground, crack resistance, and the like. It is for the purpose.

  As a result of intensive studies in view of the problems of the prior art as described above, the present inventors have used a modified silicate mixed with a specific alkyl chain as a silicate compound, and further contains an organic tin compound containing a sulfur atom. As a result, the present invention was completed.

That is, the coating composition of the present invention has the following characteristics.
1. For 100 parts by weight of the solid content of the coating resin (A) containing acrylic polyol and polyisocyanate ,
The modified silicate compound (B) in which the linear alkyl group having 1 to 2 carbon atoms and the isobutyl group are mixed at an equivalent ratio of 95: 5 to 50:50 is 0.1 to 20 parts by weight in terms of SiO ₂ ;
A coating composition comprising 0.01 to 10 parts by weight of an organic tin compound (C) containing a sulfur atom.
2. 1. A light stabilizer is further contained at a ratio of 0.01 to 20 parts by weight as an amine compound (D) with respect to 100 parts by weight of a solid content of a resin for coatings . The coating composition as described.

  According to the present invention, compared with the case where a conventionally known silicate compound is blended, the hydrophilic function of the formed coating film surface and thus the anti-contamination effect can be enhanced, and the followability of the formed coating film to the ground and crack resistance are improved. The performance which was excellent in property etc. can be obtained. Furthermore, advantageous effects are obtained in terms of cost and the like.

  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 (A), a modified silicate compound (B), and an organic tin compound (C) containing a sulfur atom as essential components.

  Examples of the coating resin (A) (hereinafter also referred to as “component (A)”) include acrylic resins, polyester resins, polyether resins, polyurethane resins, acrylic silicon resins, fluororesins, vinyl acetate resins, epoxy resins, and the like. Or these composite systems etc. can be mentioned. These can be used alone or in combination of two or more. Examples of the form of the component (A) 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 component (A) in the present invention may have crosslinking reactivity. When the component (A) is a crosslinking reaction type 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 component (A) in the present invention is usually about -20 to 80 ° C (preferably -10 to 60 ° C).

  In the present invention, as the silicate compound, a linear alkyl group having 1 to 2 carbon atoms (hereinafter also simply referred to as “linear alkyl group”) and a branched alkyl group having 3 or more carbon atoms (hereinafter also simply referred to as “branched alkyl group”). Contains a modified silicate compound (B) (hereinafter also referred to as “component (B)”). In the present invention, the hydrophilicity of the coating film surface is increased by the action of the modified silicate compound (B), and excellent performances such as contamination resistance, followability to the ground, and crack resistance can be exhibited.

As the linear alkyl group in component (B), one or more selected from a methyl group and an ethyl group can be used. Among these, a methyl group is preferable in the present invention.
On the other hand, as the branched alkyl group, isopropyl group, isobutyl group, sec-butyl group, t-butyl group, isoheptyl group, isopentyl group, neopentyl group, t-pentyl group, 1-methylbutyl group, 2-methylbutyl group, 1, 2-dimethylpropyl group, 1-ethylpropyl group, 1-methylpentyl group, 2-methylpentyl group, 3-methylpentyl group, 4-methylpentyl group, 1,1-dimethylbutyl group, 2,2-dimethylbutyl Group, 3,3-dimethylbutyl group, 1,2-dimethylbutyl group, 2,3-dimethylbutyl group, 1,3-dimethylbutyl group, 1-ethylbutyl group, 2-ethylbutyl group, 1,1,2- Trimethylpropyl group, 1,2,2-trimethylpropyl group, 1-ethyl-1-methylpropyl group, 1-ethyl-2-methylpropyl group, Sookuchiru group, and the like. In the present invention, among them, a branched alkyl group having 3 to 6 carbon atoms is preferable, and a branched butyl group having 4 carbon atoms is particularly preferable.

  Specifically, the modified silicate having a linear alkyl group and a branched alkyl group 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 linear alkyl group having 1 to 2 carbon atoms and a branched alkyl group having 3 or more carbon atoms) hydrolyzing a tetraalkoxysilane represented by Allow to condense. A known method can be adopted as the condensation method, and the average degree of condensation after the condensation may be about 2 to 100 (preferably 4 to 20). 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 monoisopropoxytrimethoxysilane, monoisopropoxytriethoxysilane, monoisobutoxytrimethoxysilane, monoisobutoxytriethoxysilane, diisobutoxydimethoxysilane, and the like. Can be mentioned.

(2) A tetramethoxysilane condensate and / or a tetraethoxysilane condensate is reacted with an alcohol having a branched alkyl group having 3 or more carbon atoms (transesterification reaction). Examples of the alcohol in this method include isopropyl alcohol, isobutyl alcohol, sec-butyl alcohol, t-butyl alcohol, isoamyl alcohol, 2-methyl-1-pentanol, 4-methyl-2-pentanol, 2-ethyl- Examples include 1-butanol. As the tetramethoxysilane condensate and / or tetraethoxysilane condensate, those having an average degree of condensation of about 2 to 100 (preferably 4 to 20) may be used.

(3) Tetramethoxysilane and / or tetraethoxysilane are reacted with water and an alcohol having a branched alkyl group having 3 or more carbon atoms. In this method, the hydrolysis condensation reaction and the transesterification reaction can be performed in parallel. The average degree of condensation by the hydrolysis condensation reaction may be about 2 to 100 (preferably 4 to 20). As the alcohol, the same compound as the above (2) can be used.

In the component (B) in the present invention, the linear alkyl group having 1 to 2 carbon atoms and the branched alkyl group having 3 or more carbon atoms are usually 95: 5 to 50:50, preferably 90:10 to 55:45. Preferably, it is mixed at an equivalent ratio of 85:15 to 60:40. If the mixing ratio of the straight chain alkyl group and the branched alkyl group is within such a range, the effects of the present invention can be sufficiently exerted. When the ratio between the straight chain alkyl group and the branched alkyl group is out of the above range, the hydrophilicity of the coating film surface becomes insufficient, and a remarkable effect is obtained in terms of contamination resistance, followability to the ground, crack resistance, etc. I can't.
In the method for producing the modified silicate compound exemplified in the above (1) to (3), the type and amount of the raw material compound are appropriately adjusted so that the equivalent ratio of the linear alkyl group to the branched alkyl group is within the above range. That's fine.

  In the present invention, a silicate compound other than the component (B) can be used in combination, but 80% by weight or more (preferably 95% by weight or more) of the total silicate compound is constituted by the component (B). It is desirable.

The mixing ratio of the component (B) is 0.1 to 20 parts by weight (preferably 0.3 to 10 parts by weight, more preferably 0.1 parts by weight) in terms of SiO _{2 with} respect to 100 parts by weight of the solid content of the component (A). It may be set within a range of 5 to 5 parts by weight. When the mixing ratio of the component (B) 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.

  The composition of the present invention contains an organic tin compound (C) containing sulfur atoms (hereinafter referred to as “component (C)”) as an essential component. The component (C) is a component that greatly contributes to improving the hydrophilicity of the coating film, particularly to improving the hydrophilicity in the initial stage of coating film formation, and exhibits a function of improving the stain resistance. Furthermore, the component (C) has almost no adverse effect on the stability at the time of mixing the silicate compound and the pot life after mixing. That is, in the present invention, by using the component (C), the hydrophilicity of the formed coating film can be enhanced while ensuring practical mixing stability and pot life.

  Examples of the component (C) include dibutyltin thioglycolate, dibutyltin bisisononyl 3-mercaptopropionate, dibutyltin bisoctyl3-mercaptopropionate, dibutyltin bisoctylthioglycolate, dibutyltin bismethoxybutylmercaptoprote Pionate, dibutyltin bisisooctylthioglycolate, dibutyltin bis-2-ethylhexylthioglycolate, dioctyltin bisisooctylthioglycolate, dioctyltin bisoctylthioglycolate, dimethyltin bisdosyl mercaptide, dimethyltin bis Octyl thioglycolate, dimethyltin bis (octylthioglycolate) salt, monooctyltin trisisooctylthioglycolate, monomethyltin trisoctylthioglycolate, etc. It is.

  (C) The mixing ratio of a component is 0.01-10 weight part normally with respect to 100 weight part of solid content of (A) component, Preferably it is 0.05-5 weight part. Within such a range, the hydrophilicity of the formed coating film can be sufficiently enhanced while ensuring practical performance in the mixing stability and pot life of the paint.

  In the composition of the present invention, an amine compound (D) (hereinafter referred to as “component (D)”) can be mixed in addition to the components described above. By mixing the component (D), it is possible to improve the adhesion when the composition of the present invention is applied (recoated). Furthermore, (D) component contributes also to physical-property improvement, such as stain resistance and curability, by interaction with the said modified | denatured silicate compound (B).

  Examples of the component (D) include ethylamine, dimethylamine, diamylamine, cyclohexylamine, aniline, hexamethylenediamine, ethylenediamine, trimethylamine, triethylamine, tripropylamine, tributylamine, triphenylamine, dimethyldodecylamine, dimethylbenzylamine, In addition to dimethylcyclohexylamine, pyridine, morpholine, etc., ethanolamine, diethanolamine, dimethylethanolamine, N-methyldiethanolamine, triethanolamine, ethylphenylethanolamine and other alkanol group-containing amine compounds, triethylenediamine ([2,2,2 ] Amino such as diazabicyclooctane), tetramethylethylenediamine, pentamethyldiethylenetriamine 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 component (D), 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 component (D), 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 suitable. By using such a compound, physical properties such as recoatability, stain resistance and curability can be further enhanced.

  The mixing ratio of the component (D) 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 component (A). Within such a range, sufficient effects can be obtained in recoatability, stain resistance, curability, and the like, and it is also preferable in terms of securing the pot life.

  In the composition of the present invention, in addition to the above-mentioned components, infrared reflective powder and / or infrared transmissive powder (E) (hereinafter referred to as “component (E)”) can be contained. In this invention, it becomes possible by mixing this (E) component to suppress the thermal storage of the coating film by sunlight, coloring a coating material in a desired color. Furthermore, in addition to the characteristics of the component (E), the adhesion of contaminants to the coating surface is effectively suppressed by the hydrophilizing action of the components (B), (C), etc. Therefore, a sufficient heat shielding function is exhibited.

Specifically, as the infrared reflective powder, for example, aluminum flake, titanium oxide, barium sulfate, zinc oxide, calcium carbonate, silicon oxide, aluminum oxide, magnesium oxide, zirconium oxide, yttrium oxide, indium oxide, iron-chromium composite Examples thereof include oxides, manganese bismuth composite oxides, and manganese yttrium composite oxides.
On the other hand, examples of the infrared transmitting powder include perylene pigment, azo pigment, yellow 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 present invention, the infrared reflective powder is a metal oxide (silicon oxide, having a refractive index of 1.3 to 2.0 (preferably 1.4 to 1.8) and an average particle size of 0.1 to 1 μm. (Including aluminum oxide). By using such a metal oxide, the heat storage suppression effect of the coating film can be further enhanced. In particular, it is effective when the lightness of the Munsell display system is 8 or less (or 7 or less) in the color tone of the formed coating film.

  In the composition of the present invention, by containing the component (E), a coating film having an infrared reflectance of 20% or more (preferably 40% or more, more preferably 55% or more), or an infrared 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 per 100 parts by weight of the solid content of the component (A). Parts by weight. 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 addition, various additives that can be usually used in 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 it is composed of the coating resin (A), the modified silicate compound (B), and the organotin compound (C) containing a sulfur atom. However, it is usually desirable to make a two-component paint comprising a main agent containing the component (A) and the component (C) and a curing agent containing the component (B). Such a form is preferable in terms of ensuring the stability of the coating material and exhibiting antifouling performance. Components such as an amine compound, infrared reflecting powder, and infrared transmitting powder may be uniformly mixed with the main agent by a conventional method.
When the coating resin (A) 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 (A) has a hydroxyl group, an isocyanate compound can be mixed with the curing agent.

  In the present invention, by using each component as described above as an essential component, it is possible to obtain a sufficient hydrophilization function and consequently a stain resistance effect even if the amount of the silicate compound is small compared with the prior art. This is also advantageous in terms of followability to the ground and crack resistance. 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 composition of the present invention can be used for surface finishing of various base materials such as concrete, mortar, siding board, extruded board, porcelain tile, metal, glass, wood, plastic, etc., mainly for buildings, civil engineering structures, etc. It is used to protect the housing of At this time, the composition of the present invention is applied as the final finished surface, and can be directly applied to the base material, or has been subjected to some surface treatment (such as a base treatment with a sealer, surfacer, filler, etc.). Although it is possible to paint on top, it is not particularly limited. As a coating method, methods such as brush coating, spray coating, and roller coating can be appropriately employed. In addition, when coating a dry building material, it can be pre-coated at a factory or the like by a flow coater, a roll coater or the like.

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

(Production of modified silicate compound)
・ Modified silicate compound (1)
52 parts by weight of isobutyl alcohol and 0.03 part by weight of dibutyltin dilaurate as a catalyst are added to 100 parts by weight of a methyl silicate condensate (weight average molecular weight 1000, average condensation degree 8, nonvolatile content 100%), and after mixing Then, a methanol removal reaction was performed at 75 ° C. for 8 hours to produce a modified silicate compound (1). In this modified silicate compound (1), the equivalent ratio of methyl group to isobutyl group was 62:38, and the residual silica ratio obtained by firing at 900 ° C. was 43% by weight.

・ Modified silicate compound (2)
52 parts by weight of n-butyl alcohol and 0.03 part by weight of dibutyltin dilaurate as a catalyst are added to 100 parts by weight of a methyl silicate condensate (weight average molecular weight 1000, average condensation degree 8, nonvolatile content 100%), After mixing, a demethanol reaction was performed at 75 ° C. for 8 hours to produce a modified silicate compound (2). In this modified silicate compound (2), the equivalent ratio of methyl group to n-butyl group was 62:38, and the residual silica ratio obtained by baking at 900 ° C. was 43% by weight.

(Manufacture of main agent)
・ Main agent (1)
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) is oxidized against 200 parts by weight. Conventionally, 86 parts by weight of titanium (refractive index: 2.71, average particle size: 0.3 μm), 18 parts by weight of mineral spirit, 1 part by weight of dibutyltin bisoctyl 3-mercaptopropionate, and 1 part by weight of a silicone-based antifoaming agent. The main agent (1) was produced by uniformly mixing and stirring.

・ Main agent (2)
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) is oxidized against 200 parts by weight. 86 parts by weight of titanium (refractive index 2.71, average particle size 0.3 μm), 2 parts by weight of bis (1,2,2,6,6-pentamethyl-4-piperidyl) sebacate (molecular weight 508, pKb5.5), The main agent (2) was produced by uniformly mixing and stirring 18 parts by weight of mineral spirit, 1 part by weight of dibutyltin bisoctyl 3-mercaptopropionate, and 1 part by weight of a silicone-based antifoaming agent by a conventional method.

・ Main agent (3)
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) is oxidized against 200 parts by weight. 43 parts by weight of titanium (refractive index 2.71, average particle diameter 0.3 μm), 43 parts by weight of aluminum oxide (refractive index 1.76, average particle diameter 0.6 μm), bis (1,2,2,6, 6-pentamethyl-4-piperidyl) sebacate (molecular weight 508, pKb 5.5) 2 parts by weight, mineral spirit 18 parts by weight, dibutyltin bisoctyl 3-mercaptopropionate 1 part by weight, silicone-based antifoaming agent 1 part by weight The main agent (3) was produced by uniformly mixing and stirring by the method.

・ Main agent (4)
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) is oxidized against 200 parts by weight. Titanium (refractive index 2.71, average particle size 0.3 μm) 86 parts by weight, mineral spirit 18 parts by weight, dibutyltin dilaurate 1 part by weight, silicone-based antifoaming agent 1 part by weight are uniformly mixed and stirred by a conventional method. By doing this, the main agent (4) was manufactured.

・ 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) is oxidized against 200 parts by weight. By uniformly mixing and stirring titanium (refractive index: 2.71, average particle size: 0.3 μm) 86 parts by weight, mineral spirit 18 parts by weight, and silicone-based antifoaming agent 1 part by weight, the main agent (5 ) Was manufactured.

(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)
10 parts by weight of Solvesso 100 (manufactured by Exxon Chemical) and 50 parts by weight of the modified silicate compound (2) 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 (3) was produced by mixing.

・ Curing agent (4)
40 parts by weight of isocyanurate structure-containing polyisocyanate (non-volatile content 100% by weight, NCO content 21% by weight), 45 parts by weight of Solvesso 100 (manufactured by Exxon Chemical), methyl silicate condensate (weight average molecular weight 1000, average condensation) The curing agent (4) was produced by uniformly mixing 15 parts by weight (degree 8, nonvolatile content: 100%).

・ Curing agent (5)
Curing agent (5) 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.

[I] Test Example 1
(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 is 4.3 parts by weight in terms of SiO _{2 with} respect to 100 parts by weight of the resin solid content.

・ Paint B
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 B. The mixing ratio of the modified silicate compound in the paint B is 4.3 parts by weight in terms of SiO _{2 with} respect to 100 parts by weight of the resin solid content.

・ Paint C
The base 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 C. The mixing ratio of the modified silicate compound in the coating material C is 4.3 parts by weight in terms of SiO _{2 with} respect to 100 parts by weight of the resin solid content.

・ Paint D
The main agent (4) 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 is 4.3 parts by weight in terms of SiO _{2 with} respect to 100 parts by weight of the resin solid content.

・ Paint E
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 E. The mixing ratio of the modified silicate compound in the coating material E is 4.3 parts by weight in terms of SiO _{2 with} respect to 100 parts by weight of the resin solid content.

・ Paint F
The base agent (5) and the curing agent (2) produced by the above method were uniformly mixed at a weight ratio of 86:14 to obtain paint F. The mixing ratio of the modified silicate compound in the paint F is 4.3 parts by weight in terms of SiO _{2 with} respect to 100 parts by weight of the resin solid content.

・ Paint G
The main agent (5) and the curing agent (3) 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 modified silicate compound in the paint G is 10.7 parts by weight in terms of SiO _{2 with} respect to 100 parts by weight of the resin solid content.

(Test method)
・ Contact angle measurement An epoxy base coat was applied to a 300 mm × 150 mm × 1 mm aluminum plate so that the dry film thickness was 30 μm, and was dried in a standard state (temperature 23 ° C., relative humidity 50%) for 8 hours. Thereafter, each paint 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.
The contact angle of the coating surface of the test specimen obtained by the above method was measured. The contact angle was measured with a CA-A type contact angle measuring device manufactured by Kyowa Interface Science Co., Ltd.
Next, this specimen was placed under the corrugated plastic corrugated board (installed so that the rainwater flowing from the straw touches the paint film surface of the specimen) and exposed outdoors. The contact angle on the surface of the coating film after a month was measured. At this time, the appearance of the coating film (contamination state) was also confirmed.

-Pot life Time Each paint was put in a container, covered and allowed to stand in a standard state, and the state after 8 hours was examined. The evaluation criteria were “◯” when the viscosity was neither increased nor aggregated, and “X” when the viscosity was increased or aggregated.

・ Cooling / cooling test A slate plate of 300 mm x 150 mm x 6 mm was coated with an epoxy-based primer to a dry film thickness of 30 µm, dried in standard conditions for 8 hours, and then waterproofed according to JIS A6909. The multi-layer finish coating material E main material was applied so that the dry film thickness was 2 mm, and was 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. The evaluation criteria were “◯” for those where no cracks occurred, “Δ” for those where slight cracks occurred, and “X” where cracks were clearly cracked.

(Test results)
As a result of carrying out the above tests, the contact angle, pot life, and heating / cooling repetition test were as shown in Table 1 below. The appearance of the coating film after 1 week and 1 month after the exposure was good in all the test specimens, but the test plates using the paint A, the paint B, the paint C, and the paint D were particularly excellent. In general, paint A, paint B, and paint C had a sufficient pot life, and were excellent in the hydrophilic function and stain resistance of the coating film surface, and also in the ability to follow the ground.

[II] Test example 2
(Manufacture of paint)
・ Paint H
A main agent (2 ′) prepared by mixing phthalocyanine green, phthalocyanine blue, perylene red, and benzimidazolone yellow with the aforementioned main agent (2) into a gray color having a brightness of 6 Munsell display system, and a curing agent (1 ) Was uniformly mixed at a weight ratio of 86:14 to obtain paint H. The mixing ratio of the modified silicate compound in the coating material H is 4.1 parts by weight in terms of SiO _{2 with} respect to 100 parts by weight of the resin solid content.

・ Paint I
The main agent (3 ′) prepared by mixing phthalocyanine green, phthalocyanine blue, perylene red, and benzimidazolone yellow with the above main agent (3) and having the same color as the paint H, and a curing agent (1) 86: The paint I was obtained by uniformly mixing at a weight ratio of 14. The mixing ratio of the modified silicate compound in the paint I is 4.1 parts by weight in terms of SiO _{2 with} respect to 100 parts by weight of the resin solid content.

・ Paint J
The main agent (5 ′) prepared by mixing phthalocyanine green, phthalocyanine blue, perylene red, and benzimidazolone yellow with the above-mentioned main agent (5) and the same color as the paint H, and a curing agent (4) 86: The paint J was obtained by mixing uniformly at a weight ratio of 14. The mixing ratio of the modified silicate compound in the coating material J is 4.1 parts by weight in terms of SiO _{2 with} respect to 100 parts by weight of the resin solid content.

・ Paint K
The main agent (5 ′) and the curing agent (5) prepared by mixing phthalocyanine green, phthalocyanine blue, perylene red, and benzimidazolone yellow with the above-described main agent (5) and having the same color as the paint H are 86: The paint K was obtained by uniformly mixing at a weight ratio of 14.

(Test method)
In Test Example 2, in addition to the test similar to Test Example 1 described above, the following heat shield test was performed.

・ 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 of the heat shielding test are: ◎ for the specimen back surface temperature of less than 65 ° C, ◯ for 65 ° C to less than 70 ° C, △ for 70 ° C to less than 80 ° C, x for 80 ° C or more It was.

(Test results)
The test results are shown in Table 2. Among these, paint H and paint I exhibited excellent heat shielding performance, and also resulted in excellent pot life, hydrophilicity of the coating film surface, stain resistance, and followability to the ground.

Claims (2)

For 100 parts by weight of the solid content of the coating resin (A) containing acrylic polyol and polyisocyanate ,
The modified silicate compound (B) in which the linear alkyl group having 1 to 2 carbon atoms and the isobutyl group are mixed at an equivalent ratio of 95: 5 to 50:50 is 0.1 to 20 parts by weight in terms of SiO ₂ ;
A coating composition comprising 0.01 to 10 parts by weight of an organic tin compound (C) containing a sulfur atom. The coating composition according to claim 1 , further comprising a light stabilizer in an amount of 0.01 to 20 parts by weight as an amine compound (D) with respect to 100 parts by weight of a solid content of the resin for coatings.