JP3245519B2 - Paint composition - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to crack resistance, flexibility, stain resistance, water resistance, alkali resistance, acid resistance, etc., which are applied to outdoor buildings or structures for the purpose of decoration or protection. The present invention relates to a coating composition that forms an excellent coating film.

[0002]

2. Description of the Related Art Conventionally, outdoor paints having excellent weather resistance have been developed as paints applied to outdoor structures and the like. In particular, the amounts of the acrylic silicone resin paint and the fluororesin paint have been considered to be suitable as outdoor paints because the paint film is less deteriorated by sunlight, rain and the like. However, these paints are contaminated on the paint film surface due to the effects of dust, sand dust, iron powder and acid rain which has recently become a problem during exposure, and the paint film appearance deteriorates. There were drawbacks.

As a technique for preventing the adhesion of dust in the atmosphere, various antistatic agents for lowering the surface resistivity of the coating film and preventing the electrostatic adhesion of dust and the like, for example, an electrostripper TS-2B ( Kao Corporation, trade name / surfactant system), Colcoat R (Colcoat Corporation,
There is known a method of adding (trade name, alkyl silicate type) to a paint or applying this to a coating film surface for treatment. However, in these methods, since the substance to be added is essentially poor in water resistance, it is difficult to maintain its effect, and it is not suitable for outdoor use.

Further, as an organic coating composition having excellent acid rain resistance, there has been proposed a composition obtained by adding a condensation reaction product of an alkyl silicate oligomer and a silane coupling agent (hydrolysis product of epoxy-functional silane) to the coating. (JP-A-6-306328). The condensation reaction product prepared by this method becomes a mixture with the alkyl silicate oligomer, the silane coupling agent oligomer, and the block condensation product of both, and remains because the epoxy group is not uniformly introduced into the condensation reaction product. Alkyl silicate oligomers are eluted by water, and as a result, there is a disadvantage that the water resistance of the coating film, particularly the alkali resistance, is reduced. Also,
The coating film has disadvantages that cracks are easily generated during the formation of the coating film and the flexibility is not sufficient.

[0005]

The present inventors have conducted intensive studies to solve the above-mentioned problems, and as a result, have found that the water contact angle of the coating film surface and the contamination of the contaminants to the coating film surface during outdoor exposure. Adhesion has a close relationship in that the smaller the water contact angle, the smaller the adhesion of contaminants. As a substance that reduces the water contact angle, an organic functional group and a hydrolyzable group are contained in one molecule having a specific structural unit. A coating composition containing a silicone compound, stain resistance, water resistance, alkali resistance,
It has been found that a coating film having excellent acid resistance and the like can be provided, and the present invention has been completed.

According to the present invention, there is provided an organic solvent-based coating composition comprising at least one compound selected from the group consisting of (1) an epoxy group, a mercapto group, a (meth) acryloyl group, a vinyl group and a haloalkyl group, based on all silicon atoms. D of a silicon structural unit containing an organic functional group
5 to 80 mol% of a unit or T ₁ unit; (2) a general formula RSiZ _{3 wherein} R represents an alkyl group having 1 to 3 carbon atoms, and Z represents another group represented by a hydrolyzable group or a siloxane bond. 0.1 the T ₂ units as trifunctional silicon structural unit represented by any one representing the 'residues that are bonded to silicon atoms
(3) containing 10 to 94.9 mol% of a Q unit as a tetrafunctional silicon structural unit represented by the general formula SiZ ₄ [wherein Z is the same as above], provided that T The total amount of ₂ units and Q units is 20-9
A silicone compound having an organic functional group and a hydrolyzable group is compounded in one molecule having an average degree of polymerization of 3 to 100, which is 5 mol%, and the content of the silicone compound is determined by coating.
0.1 to 5 parts by weight per 100 parts by weight of the resin solid component of the composition
It is intended to provide a coating composition characterized by being 0 parts by weight .

[0007]

BEST MODE FOR CARRYING OUT THE INVENTION The present inventors have found that a coating film having a small water contact angle is less likely to adhere to contaminants such as dust in the air during outdoor exposure than a coating film having a large water contact angle. It was found that the stain resistance was excellent. A coating film having hydrophilicity simultaneously reduces the surface resistivity of the coating film, prevents electrostatic adhesion of contaminants such as dust, and the contaminants that have once adhered have a weaker adhesion, and thus have a reduced rainfall. It is easily washed away by the action of, for example, and has excellent stain resistance.

[0008] The method of forming the surface of a coating film having a hydrophilic property includes, for example, adding a hydrophilic substance (an antistatic agent,
(Condensation reaction product of an alkyl silicate oligomer and a hydrolysis compound of a silane coupling agent), but it is suitable for outdoor use because the water resistance and alkali resistance of the coating film are simultaneously reduced. Not.

According to the present invention, an epoxy group, a mercapto
Group, (meth) acryloyl group, vinyl group, and haloal
Contains at least one organic functional group selected from kill groups
Silane coupling agent (hereinafter sometimes referred to as the silane coupling agent of the present invention), alkyltrialkoxysilane and tetraalkoxysilane are partially co-hydrolyzed and condensed, so that these components are compared in the silicone compound. Since it is uniformly introduced, a coating film having excellent water resistance, alkali resistance and the like can be formed. In addition, the alkyl trialkoxysilane component is a component not used in the above-mentioned references, and a silane coupling agent not using this component and a partially co-hydrolyzed tetraalkoxysilane cause cracks at the time of coating film formation. There are drawbacks such as easy coating and inferior flexibility of the coating film. However, these components can improve these drawbacks and form a coating film having excellent stain resistance.

As the organic solvent-based coating composition used in the present invention, known uncrosslinked and crosslinked coating compositions conventionally used for outdoor use can be used. The uncrosslinked and crosslinked coating composition is composed of a resin solution obtained by dissolving or dispersing an uncrosslinked or crosslinked organic resin in an organic solvent. A film is formed.

Examples of the non-crosslinked type paint composition include nitrified cotton lacquer, acrylic lacquer paint, vinyl resin paint, fluororesin paint and the like.

As the crosslinkable coating composition, those which can be crosslinked at room temperature or by heating can be suitably used. Specifically, for example, oxidized cross-linkable paints such as unsaturated fatty acid-modified alkyd resin paints, melamine cross-linkable paints such as polyester melamine resin paints, acrylic melamine resin paints, and fluorine melamine resin paints; (block) polyisocyanate acrylic resin paints , (Block) polyisocyanate polyester resin paint, (block) polyisocyanate fluororesin paint, etc .; isocyanate crosslinkable resin paint; moisture-crosslinkable resin paint, such as alkoxysilane group-containing acrylic resin paint; epoxy, epoxy group-containing acrylic resin paint, etc. Crosslinkable resin paints and the like can be mentioned.

As the organic solvent, any solvent can be used without particular limitation as long as it dissolves or disperses the resin and does not substantially react with the functional group or hydrolyzable group of the silicone compound. Specifically, for example, acetates (ethyl acetate, propyl acetate, etc.), ketones (methyl isobutyl ketone, etc.), aromatic hydrocarbons (xylene, toluene, etc.), aliphatic hydrocarbons (heptane, etc.), Examples include alcohols (such as propyl alcohol) and ethers (such as ethyl cellosolve and butyl cellosolve). These organic solvents can be used alone or in combination of two or more.

The organic solvent-based coating composition used in the present invention may optionally contain, for example, a coloring agent, a filler, a curing catalyst, an anti-dripping agent, an anti-cissing agent, an ultraviolet absorber, and an ultraviolet stabilizer. Can be used.

The silicone compound used in the present invention comprises:
(1) A silicon structural unit containing at least one organic functional group selected from an epoxy group, a mercapto group, a (meth) acryloyl group, a vinyl group, and a haloalkyl group (D
Unit or T ₁ unit) in an amount of 5 to 80 mol% (based on total silicon atoms), and (2) a general formula RSiZ ₃ [wherein R represents an organic substituent having 1 to 3 carbon atoms, and Z represents a hydrolyzate. trifunctional silicon structural units (T ₂ units) 0.1 to 30 mol% represented by indicating one of the residues that are bonded to other silicon atoms] by gender group or a siloxane bond (to total silicon atoms (3) containing 10 to 94.9 mol% (total silicon atoms) of a tetrafunctional silicon structural unit (Q unit) represented by the general formula SiZ ₄ (wherein Z is the same as described above). Provided that the total amount of (T ₂ units + Q units) is 20 to 9
5 mol% (based on total silicon atoms), and the average degree of polymerization is 3 to
It is a silicone compound having an organic functional group and a hydrolyzable group simultaneously in one molecule of 100.

The (1) organic functional group in the silicon structural unit of the silicone compound forms a chemical bond with an organic resin by a chemical reaction, forms a hydrogen bond by a polar structure, or forms an interaction based on affinity. It functions to prevent the silicone compound from being detached from the coating film. The organic functional group may be directly bonded to silicon, or may be bonded to silicon via an organic substituent. As the organic functional group and the organic substituent, any of those known as organic substituents of a so-called silane coupling agent can be used. The following can be mentioned as specific examples.

Γ-glycidoxypropyl group β- (3,4-epoxycyclohexyl) -ethyl group 5,6-epoxyhexyl group 9,10-epoxydecyl group γ-mercaptopropyl group β- (mercaptomethylphenyl) ethyl Group 6-mercaptohexyl group 10-mercaptodecyl group mercaptomethyl group γ-methacryloxypropyl group γ-methacryloxymethyl group γ-acryloxypropyl group γ-acryloxymethyl group vinyl group 5-hexenyl group 9-decenyl group γ-chloropropyl group γ-bromopropyl group trifluoropropyl group These organic functional groups and their substituents can be contained alone or in combination of two or more.

The silicon structural unit containing these organic functional groups has two (D units) or three (T units) hydrolyzable groups capable of forming a siloxane bond by a hydrolytic condensation reaction.
₁ unit) can be used.

The content of the silicon structural unit containing these organic functional groups is in the range of 5 to 80 mol% based on all silicon atoms in the silicone compound. Content is 5 mol%
If it is less than 1, the ability to fix the silicone compound in the coating film is insufficient, and the silicone compound is easily eluted from the coating film. On the other hand, if the content exceeds 80 mol%, the hydrophilicity of the present silicone compound becomes insufficient, and good stain resistance cannot be obtained, which is not preferable. A particularly preferred content is in the range of 10 to 50 mol%.

In the silicone compound, the general formula RSi
The silicon structural unit (T ₂ unit) represented by Z ₃ is a compound having three hydrolyzable groups capable of forming a silanol group or condensing with another silicon atom to form a siloxane bond. Is a unit that can impart flexibility and flexibility without significantly lowering the hydrophilicity of the coating film. When this unit is not contained, there is a disadvantage that the partial cross-linking of the coating film becomes high in density and cracks are generated in the coating film.

Alkyl represented by R in the general formula RSiZ ₃
The carbonyl group has 1 to 3 carbon atoms, and is preferably, for example, a methyl group, an ethyl group, or a propyl group. Among them, the methyl group has the least hydrophobicity, and thus exhibits an effect excellent in stain resistance.

As the hydrolyzable group represented by Z in the general formula RSiZ ₃ , conventionally known groups can be used.
The following can be exemplified. Methoxy group Ethoxy group Butoxy group Isopropenoxy group Acetoxy group Butanoxime group These hydrolyzable groups can be contained alone or in combination of two or more. A methoxy group and an ethoxy group are particularly preferable because they have good storage stability of the coating material and can exhibit stain resistance early because of their excellent hydrolyzability.

The content of the T ₂ unit represented by the general formula is in the range of 0.1 to 30 mol% (based on total silicon atoms) in the silicone compound. If the content is less than 0.1 mol%,
It is not preferable because flexibility is not imparted to the coating film and cracks or the like are generated and a good coating film cannot be obtained. On the other hand, if the content exceeds 30 mol%, although sufficient flexibility is imparted, the hydrophobicity becomes too strong, resulting in insufficient hydrophilicity and poor stain resistance, which is not preferable. Furthermore, the content of T ₂ units is preferably in the range of 1 to 25 mol%.

In the silicone compound, the general formula SiZ
_The silicon structural unit (Q unit) represented by 4 is one containing four hydrolyzable groups capable of finally forming a silanol group or condensing with another silicon atom to form a siloxane bond. , A unit that can impart hydrophilicity to the coating film. This Q unit has a content of 1 in the silicone compound.
The range is from 0 to 94.9 mol% (based on total silicon atoms).
If the content is less than 10 mol%, the hydrophilicity becomes insufficient, so that good stain resistance, acid resistance, alkali resistance and the like cannot be obtained, which is not preferable. On the other hand, the content is 94.
If it exceeds 9 mol%, although hydrophilicity is sufficiently imparted, the hydrophilicity is increased, and the silicone compound is liable to fall off from the coating film, and the properties are degraded with time.
Further, the content of the Q unit is preferably in the range of 25 to 90 mol%.

In the silicone compound, the total content of the T ₂ unit and the Q unit is the amount excluding the content of the organic functional group-containing silicon structural unit, and is 20 to 95 mol%.
Range.

The degree of polymerization of the silicone compound is from 3 to 100.
Range. If the degree of polymerization is less than 3, the silicone compound volatilizes from the coating film during the curing process of the coating film, or the coating surface cannot be provided with sufficient hydrophilicity, or is easily eluted from the coating film. A coating film having excellent stain resistance and durability cannot be formed. On the other hand, when the degree of polymerization exceeds 100, the dispersion of the silicone compound in the coating film is poor, and it is difficult to form a uniform coating film, so that finish properties, stain resistance, durability and the like are inferior. Further, the degree of polymerization is preferably in the range of 5 to 80.

The silicone compound can be produced by various conventionally known methods as long as the above conditions are satisfied. Specifically, the following examples can be given, but are not limited to the methods described below. (A) Epoxy group, mercapto group, (meth) acryloy
, A vinyl group, and a haloalkyl group.
A silane coupling agent containing at least one organic functional group [a component having a (1) unit, hereinafter the same meaning], an alkyl trifunctional silane [a component having a (2) unit, a (T ₂ unit) The same meaning below), and a tetrafunctional silane [a component having (3) units, (Q units)
Have the same meaning] in the presence of a hydrolysis-condensation catalyst. (Ii) The above silane coupling agent or pre-hydrolysate is reacted with an oligomer or resin obtained by partially co-hydrolyzing an alkyl trifunctional silane and a tetrafunctional silane. (C) a cohydrolysis product of the silane coupling agent with alkyl trifunctional silane is reacted those tetrafunctional silane or which was pre-partially hydrolyzed. Among these methods, the method (a) of partially co-hydrolyzing and condensing the raw material silane compound can uniformly introduce an organic functional group, a T unit and a Q unit into the silicone compound, It is particularly preferable because it can easily achieve both improvement in coating film performance such as acid resistance and alkali resistance and the like, and improvement in durability performance thereof and prevention of cracks in the coating film.

In the partial cohydrolysis condensation, the degree of partial cohydrolysis is, for example, that the average degree of polymerization is 0 when no hydrolysis is performed, and that the degree of polymerization is too high when 100% hydrolysis is performed. There is a close relationship with the degree of polymerization so that the silicone compound is gelled, and the average degree of polymerization of the silicone compound used in the present invention is adjusted to 3 to 100.

Epoxy group as starting material , mercapto
Group, (meth) acryloyl group, vinyl group, and haloal
Contains at least one organic functional group selected from kill groups
Silane coupling agent, alkyl trifunctional silane,
If the substituent and the hydrolyzable group satisfy the above-mentioned conditions, the tetrafunctional silane may be a conventionally known one. The silane coupling agent may be either trifunctional (T ₁ unit) or bifunctional (D unit).

As the hydrolysis-condensation catalyst used in the above-mentioned hydrolysis-condensation reaction, various conventionally known ones can be used. Specific examples include, for example, organic acids such as acetic acid, butyric acid, maleic acid, and citric acid; hydrochloric acid,
Inorganic acids such as nitric acid, phosphoric acid, and sulfuric acid; basic compounds such as triethylamine; tetrabutyl titanate;
And organic metal salts such as dibutyltin dilaurate; K
And F-containing compounds such as F and NH ₄ F. The above catalysts can be used alone or in combination of two or more. The amount of catalyst used is 0.000
A range of 1 to 1 mol% is preferred.

In the above hydrolysis-condensation reaction, a solvent can be used if necessary. Examples of usable solvents include alcohols such as methanol, ethanol, isopropanol and t-butanol; acetone,
Ketones such as methyl isobutyl ketone; ethers such as dibutyl ether; esters such as ethyl acetate;
Examples include aromatics such as toluene.
Particularly, solvents such as methanol, ethanol, and acetone are preferable.

The amount of water used in the partial cohydrolysis condensation reaction can be determined according to the desired degree of polymerization. Excessive addition destroys the alkoxy group and eventually leads to gelation, so it must be determined strictly. In particular, when an F-containing compound is used as a catalyst, the F-containing compound has the ability to completely promote hydrolytic condensation, so that the degree of polymerization can be determined by the amount of water added, and any molecular weight can be set, which is preferable. . That is, in order to prepare a target product having an average degree of polymerization M,
What is necessary is just to use (M-1) mol of water with respect to M mol of alkoxysilane compounds. In the case of other catalysts, it is necessary to slightly increase the amount.

The hydrolysis condensation reaction is carried out at room temperature or at 150 ° C.
It can be performed in the following temperature range. If the temperature is lower than room temperature, the progress of the reaction will be slow, which is not practical.

The mixing ratio of the silicone compound is 0.1 to 100 parts by weight of the resin solid content of the organic solvent-based coating composition.
50 parts by weight, preferably in the range of 1.0 to 20 parts by weight. When the compounding ratio is less than 0.1 parts by weight, the stain resistance, acid resistance, alkali resistance, and water resistance of the coating film are deteriorated. On the other hand, when the mixing ratio exceeds 50 parts by weight, the coating film has water resistance, It is not preferable because acid resistance and alkali resistance are deteriorated.

When the coating film formed by the coating composition of the present invention is exposed outdoors, the water contact angle gradually decreases due to the action of rain or the like, but the surface of the coating film before exposure is subjected to an acidic treatment (2). Immersed in 0.5% by weight sulfuric acid aqueous solution at 20 ° C. for 24 hours, and then the attached sulfuric acid aqueous solution was washed with water and dried.) Then, the final contact angle of the exposed coating film was estimated by measuring the water contact angle . You can do it.

In the coating composition of the present invention, the surface of the formed coating film is treated with an acid (immersed in a 2.5% by weight sulfuric acid solution at 20 ° C. for 24 hours, and then the attached sulfuric acid solution is washed with water and dried. However, the surface of the coating film preferably has a contact angle with water of 70 degrees or less, preferably 10 to 60. If the contact angle is more than 70 degrees, the stain resistance decreases, which is not preferable. If the contact angle is less than 10 degrees, the water resistance, acid resistance, alkali resistance, and the like of the coating film decrease, which is not preferable.

The coating composition of the present invention can be formed by coating the above-mentioned coating composition on a substrate and drying at room temperature or by heating. As the base material, for example, an inorganic base material such as slate and concrete; iron and steel, aluminum, zinc, and stainless steel;
Metallic substrates such as those surface-treated with zinc phosphate; plastic substrates such as polyvinyl chloride, polyethylene terephthalate, and polyethylene. In addition, a known primer, an intermediate coating,
Substrates coated with a top coat or the like can also be used.

The coating method can be performed by, for example, brush coating, spray coating, roller coating, dip coating, or the like. The coating amount is generally in the range of 1 to 100 μm, preferably 10 to 60 μm.

The conditions for drying the coating film may be selected depending on the type of the coating material.
About 1 week, heat drying at 60-300 ° C for 30 seconds-1
Think that time is enough.

[0040]

EXAMPLES Hereinafter, a fluororesin paint (Examples 1 to 9 and Comparative Examples 1 to 6), a polyisocyanate urethane resin paint (Examples 10 to 18 and Comparative Examples 7 to 12), an unsaturated fatty acid-modified alkyd resin paint ( The present invention will be described in detail with reference to Examples and Comparative Examples using Examples 19 to 27 and Comparative Examples 13 to 18. “Part” and “%” in Examples
Is based on weight.

Preparation of Silicone Compound Containing Organic Functional Group and Alkoxy Group Preparation Example of Silicone Compound A 1000 ml equipped with a thermometer, nitrogen inlet tube and dropping funnel
, 47.3 g (0.20 mol) of γ-glycidoxypropyltrimethoxysilane, 114.0 g (0.75 mol) of tetramethoxysilane, 6.8 g (0.05 mol) of methyltrimethoxysilane, 160 g of methanol (5mol) and KF 0.06g (0.001m
ol) and 17.1 g (0.95 g) of water at room temperature under stirring.
mol) was slowly added dropwise. After completion of the dropwise addition, the mixture was stirred at room temperature for 3 hours, and then heated and stirred for 2 hours under methanol reflux. Thereafter, 113 g of a colorless and transparent liquid was obtained by distilling off low-boiling components under reduced pressure and filtering. The substance obtained in this way is GPC
As a result of the measurement, the average degree of polymerization was 20.5 (set degree of polymerization = 2
0), which was almost as set. When the epoxy equivalent was measured by an epoxy ring opening method using hydrochloric acid, it was found to be 62
It was 5 g / mol (set value: 622 g / mol), and it was confirmed that a predetermined amount of epoxy groups had been introduced. When the amount of the alkoxy group was determined by the alkali cracking method, it was 45.5% (theoretical value: 46.1%). Also,
^From the measurement results of ¹ H-NMR, the structure of the obtained substance was
The structure was represented by the following average composition formula. Average composition formula:

[0042]

Embedded image

The silicone compound thus obtained is referred to as Compound A.

Compounds B to G and Comparative Examples H and J
Preparation example of silane coupling agent used, alkyl trialkoxy silane, tetraalkoxy silane,
Also, by changing the type and amount of the catalyst, compounds BG having the set structures as shown in Table 1 and compounds H and J for comparative examples were prepared. In Table 1, the blending amounts of A to J are expressed in mole units.

Instead of the partial cohydrolysis condensation method (hereinafter referred to as Production Method I), the following production method was also studied. Production Method II An organic functional group-containing alkoxysilane and a T unit alkoxysilane are co-hydrolyzed in advance, and then a condensation reaction is performed with tetraalkoxysilane. Production Method III Beforehand, tetraalkoxysilane and T-unit alkoxysilane are co-hydrolyzed, and then the organic functional group-containing alkoxysilane is subjected to a condensation reaction. Production Method IV After each component is hydrolyzed in advance, each component is mixed and subjected to a condensation reaction.

Examples 1 to 9 and Comparative Examples 1 to 6 Coatings of Examples 1 to 9 and Comparative Examples 1 to 6 were prepared with the composition (unit: parts by weight) shown in Table 2. Huccalon white enamel: Trade name, Kansai Paint Co., Ltd.
, Non-crosslinked fluororesin topcoat, resin solids content = 3
5% zinc phosphate treated zinc steel sheet (zinc basis weight: 130 on one side)
g / m ² , 1.2 mm thickness) with air spray coating with Fucalon FR primer (trade name, uncrosslinked fluororesin base coat, manufactured by Kansai Paint Co., Ltd.) so that the dry film thickness becomes about 10 μm. went. After leaving at 20 ° C. for 10 minutes, the paints of Examples 1 to 9 and Comparative Examples 1 to 6 were subjected to air spray coating so that the dry film thickness was about 25 μm.
A test plate was prepared by drying at 235 ° C. for 15 minutes. Table 2 shows the results of the coating film performance test.

Examples 10 to 18 and Comparative Examples 7 to 12 Examples 10 to 1 were prepared using the formulations (unit: parts by weight) shown in Table 3.
8. Paints of Comparative Examples 7 to 12 were prepared. Retan PAQ White Enamel: Trademark name, Kansai Paint Co., Ltd.
Steel, polyisocyanate acrylic resin top coating, resin solids content = 36% zinc phosphate treated zinc steel plate (zinc basis weight: 130 per side)
g / m ² , 1.2 mm thick) by air spray coating with a urethane CW primer (trade name, epoxy resin base coat, manufactured by Kansai Paint Co., Ltd.) so that the dry film thickness becomes about 30 μm. It dried at 30 degreeC for 30 minutes, and produced the base material. Then, the obtained base materials were prepared in Examples 10-1.
8. After applying the spray of the paints of Comparative Examples 7 to 12 so that the dry film thickness becomes about 30 μm,
After drying for minutes, a test plate was prepared. Table 3 shows the results of the coating film performance test.

Examples 19 to 27 and Comparative Examples 13 to 18 The compositions (units: parts by weight) shown in Table 4 were used to prepare Examples 19 to 2
7. The paints of Comparative Examples 13 to 18 were prepared. Neophthalite white enamel: Trade name, manufactured by Kansai Paint Co., Ltd., an unsaturated fatty acid-modified alkyd resin-based top coating, resin solids content = 32% # 320 Polished mild steel sheet treated with sandpaper (SPC
C, 0.8 mm), and air-spray-painted with Rustite NC (trade name, manufactured by Kansai Paint Co., Ltd., an unsaturated fatty acid-modified alkyd resin-based undercoat) so as to have a dry film thickness of about 30 μm. After standing at 20 ° C. for 10 minutes, the paints of Examples 19 to 27 and Comparative Examples 13 to 18 were subjected to air spray coating so that the dry film thickness was about 30 μm.
A test plate was prepared by drying at 20 ° C. for 7 days. Table 4 shows the results of the coating film performance test.

^{* 1} to ^{* 8 in} Tables 2, 3 and 4 have the following meanings. ^{* 1} : Trade name, low-condensation product of tetramethyl silicate, manufactured by Colcoat Co., Ltd. ^{* 2} : Trade name, γ-glucidoxypropyltrimethoxysilane, manufactured by Shin-Etsu Chemical Co., Ltd. ^{* 3} : Trade name, Shin-Etsu Chemical Γ-mercaptopropyltrimethoxysilane ^{* 4} ; manufactured by Kogyo Co., Ltd .; water contact angle: the test plate was immersed in 2.5% sulfuric acid at 20 ° C. for 24 hours.
After immersion for a period of time, the attached sulfuric acid solution was washed with water and dried, and then a contact angle meter D manufactured by Kyowa Chemical Co., Ltd. was used.
Using a CAA type, a drop of 0.03 cc of deionized water was dropped on the coating film surface, and the value was measured after 3 minutes at 20 ° C. ^{* 5} ; Boiling resistance: The appearance of the coating film after the test plate was immersed in boiling water at 100 ° C. for 10 hours was visually evaluated. ＝= No change in appearance with respect to the coated plate before the test. ＝= Appearance slightly changed in appearance from the coated plate before the test. ^-- = A slight change in appearance was observed on the coated plate before the test. Δ = Appearance change is observed on the coated plate before the test. × = significant change in appearance of the coated plate before the test. The appearance change was examined by examining stains, color change, swelling, cracking, glazing, peeling, softening and the like of the coated surface. ^{* 6} ; Alkali resistance A: The appearance of the coating film after immersing the test plate in 10% caustic soda water at 20 ° C. for 10 days was visually observed. The evaluation was performed in the same manner as ^{* 4} . ^{* 7} : Alkali resistance B: Test plate was immersed in 3% sodium carbonate water.
The appearance of the coating film after immersion at 0 ° C. for 3 days was visually observed.
The evaluation was performed in the same manner as ^{* 4} . ^{* 8} : Outdoor exposure test: A test plate was installed at an angle of 30 degrees on the south side of the Tokyo Plant of Kansai Paint Co., Ltd. Each of the test plates exposed for 3 months, 6 months, and 12 months was evaluated for coating film characteristics without performing sample preparation such as washing with water. Appearance (dirt): The degree of dirt on the coated surface was evaluated in the same manner as in ^{* 4} . Water contact angle: Measured by the same method as ^{* 4} without adjusting the sample (soaking in sulfuric acid, washing with water, etc.). Lightness difference (ΔL ^* ): The difference between the lightness (L value) before and after exposure was defined as ΔL ^* . For measurement of the L value, a color difference meter CR-300 manufactured by Minolta Co., Ltd. was used. The brightness difference ΔL ^* is
The smaller the numerical value, the less dirt. ^{* 9} : HMDI urethane curing agent manufactured by Kansai Paint Co., Ltd.

[0050]

[Table 1]

[0051]

[Table 2]

[0052]

[Table 3]

[0053]

[Table 4]

[0054]

The coating film obtained from the coating composition of the present invention does not stain when exposed outdoors, and has good water resistance, acid resistance and alkali resistance. Regarding the surface properties of the coating film after the exposure, the water contact angle is remarkably reduced as compared with that before the exposure, and the film shows hydrophilicity. This is because moisture and rain (especially acid rain) in the exposed environment act on the silicone compound in the coating film, and the water contact angle of the coating film surface decreases due to the action of silanol groups generated by hydrolysis, making the coating film hydrophilic. You. The hydrophilized coating weakens the adhesion of organic substances such as oil, which is one of the dirt components in the atmosphere, and is easily washed away by rain even if it once adheres to the painted surface. Is to reduce the surface resistivity (hydrophilization), dust and dust components in the air,
Prevents electrostatic adhesion of dust and the like, and forms a coating film with excellent stain resistance. The coating film formed by the coating composition of the present invention has an early decrease in water contact angle due to outdoor exposure, and reaches almost equilibrium after 3 to 6 months. The water contact angle when this equilibrium is reached is almost equal to the water contact angle after immersing the coating film before exposure in 2.5% by weight sulfuric acid aqueous solution for 24 hours. That is, the state of stain after exposure can be estimated by measuring the water contact angle when the cured coating film before exposure is immersed in 2.5% by weight sulfuric acid aqueous solution for 24 hours. The organic functional groups derived from the silicone compound react with the organic resin in the paint, form hydrogen bonds,
Or, by improving the compatibility, in order to strongly associate with the organic resin, to suppress the elution of the silicone compound from the coating film,
As a result, it is considered that performances such as stain resistance, boiling water resistance, acid resistance, and alkali resistance are improved. Furthermore,
Although the silicone compound is essentially hard, it contains a certain amount of T units, so that the coating film has excellent flexibility and can prevent cracks and the like which are easily generated on the coating film surface.

──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Kazuhiko Onishi 4-17-1, Higashi-Hachiman, Hiratsuka-shi, Kanagawa Prefecture Inside Kansai Paint Co., Ltd. (72) Inventor Masaaki Yamaya 1-10 Hitomi, Matsuida-cho, Usui-gun, Gunma Prefecture 10 Shinetsu (72) Masahiro Yoshizawa, Inventor, 1-10, Hitomi, Matsuida-cho, Usui-gun, Gunma Prefecture, Japan Inside the Silicone Electronic Materials Technology Laboratory (56) References JP-A-6-62 347605 (JP, A) JP-A-4-31475 (JP, A) JP-A-50-126033 (JP, A) JP-A-61-162560 (JP, A) JP-A-59-212256 (JP, A) JP-A-5-9439 (JP, A) (58) Fields investigated (Int. Cl. ⁷ , DB name) C09D 183/06-183/08 C09D 5/00

Claims (2)

(57) [Claims] 1. An outdoor uncrosslinked or crosslinked organic solvent-based coating composition containing (1) an epoxy group, a mercapto group, a (meth) acryloyl group, a vinyl group, and a haloalkyl group, based on all silicon atoms. D of a silicon structural unit containing at least one organic functional group selected
5 to 80 mol% of a unit or T ₁ unit; (2) a general formula RSiZ _{3 wherein} R represents an alkyl group having 1 to 3 carbon atoms, and Z represents another group represented by a hydrolyzable group or a siloxane bond. 0.1 the T ₂ units as trifunctional silicon structural unit represented by any one representing the 'residues that are bonded to silicon atoms
(3) 10 to 94.9 mol% of a Q unit as a tetrafunctional silicon structural unit represented by the general formula SiZ ₄ [wherein Z is as defined above], The total amount of ₂ units and Q units is from 20 to 95 mol%, and an average degree of polymerization is from 3 to 100. A silicone compound having an organic functional group and a hydrolyzable group is compounded in one molecule,
The content of the silicone compound is 0.1 to 50 parts by weight based on 100 parts by weight of the resin solid component of the coating composition,
The organic solvent-based coating composition, nitrified cotton lacquer, acrylic
Lacquer paint, vinyl resin paint and fluororesin paint
Uncrosslinked paint composition selected from unsaturated fatty acids
Oxidative cross-linking paint composed of modified alkyd resin paint, poly
Ester melamine resin paint, acrylic melamine resin paint
Melamine crosslinkable type composed of fluorinated melamine resin paint
Paint; (block) polyisocyanate acrylic resin coating
Material, (block) polyisocyanate polyester resin
Paint and (block) polyisocyanate fluororesin
Isocyanate cross-linked resin paint consisting of paint;
Moisture-crosslinkable tree made of acrylic resin paint containing silane group
Fat paint; Epoxy composed of epoxy group-containing acrylic resin paint
A cross-linkable paint composition selected from xy cross-linkable resin paints;
Outdoor paint composition characterized in that that. 2. The silicone compound according to claim 1, wherein the silicone compound contains at least one organic functional group selected from an epoxy group, a mercapto group, a (meth) acryloyl group, a vinyl group, and a haloalkyl group. The outdoor coating composition according to claim 1, which is obtained by partially cohydrolyzing and condensing tetraalkoxysilane.