JP3477701B2 - Paint composition - Google Patents

Description

Detailed Description of the Invention

[0001]

FIELD OF THE INVENTION The present invention relates to a novel coating composition. More specifically, the present invention contains a ceramic component, stain resistance, stain removability, weather (light) resistance, chemical resistance,
A coating that can form a high-thickness coating with excellent water resistance and appearance in a single coating operation, and that it cures sufficiently even in areas with insufficient ultraviolet irradiation, and that has high environmental protection and safety. It relates to a composition.

[0002]

2. Description of the Related Art In recent years, due to environmental changes such as air pollution,
The amount of oil drops and dust contained in the air increases, and as a result, the coating film painted on buildings and automobiles is more likely to be contaminated than before, and it is difficult to remove the dirt. Has occurred. Therefore, as the performance of the coating film, resistance to contamination, that is, stain resistance, and removability of contaminants from the contaminated coating film, that is, stain removability, have been desired. Under such circumstances, a coating film having excellent stain resistance, decontamination resistance, weather (light) resistance, gloss, appearance, water resistance, and chemical resistance can be obtained, and a high coating film can be obtained by a single coating operation. It is possible to form a thick coating film,
It has been desired to create a coating composition having excellent environmental protection and safety. Conventionally used stain resistant paints are mainly composed of a fluororesin, and the stain resistance is due to the high weather resistance of the fluororesin. The fluorine-containing resin has (1) stability resulting from the fact that the bond energy between the fluorine atom and the carbon atom is larger than the bond energy between the hydrogen atom and the carbon atom, and (2) the fluorine atom rather than the hydrogen atom. Its function is exhibited by water repellency and oil repellency due to the large atomic radius of atoms and the low surface free energy due to the low polarizability between fluorine molecules (0.68 × 10 ^-24 cc). There is. However, fluorine-containing resins have different polymerizability from ordinary acrylic monomers due to the strong electronegativity of fluorine atoms, which limits the scope of resin design. Some have limited solubility in
Although it has high functionality such as high resin price and concern about environmental impact due to the generation of hydrofluoric acid at the stage of waste treatment of coating film using fluorine-containing resin, price and usage related Problems such as restrictions and adverse environmental effects at the time of disposal are highlighted. On the other hand, recently, as a highly weather-resistant coating composition, a coating composition in which weather resistance is imparted by an acrylic polyol containing a polymerizable UV-stable monomer as an essential component has been proposed (JP-A-1-261409). ). However, this publication makes no mention of resistance to contamination. Further, as a stain resistant composition, a coating composition prepared by mixing a partial condensate of an organosilicon compound and specific silica fine particles has been proposed (JP-A-2-3).
468). However, in this publication,
No detailed description is given of the resin component used in the coating composition. Further, a coating composition containing an acrylic polyol resin, a binder, an inorganic organosol, and a solvent has been proposed (Japanese Patent Laid-Open No. 17388/1992).
No. 2). However, although this coating composition has been improved to some extent in stain resistance and weather (light) resistance, it has the drawback of insufficient stain removability. In addition, Japanese Patent Laid-Open No. 50-66596 and Japanese Patent Laid-Open No.
The photocurable coating material and the radiation curable coating material described in JP-A-4-17967 and the like can easily obtain a coating film having a high film thickness by one coating operation, but the portion where the irradiation of light or radiation is insufficient. In this case, the curing is insufficient and the weather resistance of the coating film is not always satisfactory. As described above, a coating film having a high film thickness can be obtained by one-time coating operation, is sufficiently cured even in a place where the ultraviolet irradiation is insufficient, and has weather resistance, stain resistance, and
The present situation is that no coating composition excellent in stain removability has been found so far.

[0003]

Under the above circumstances, the present invention provides a high film thickness excellent in stain resistance, stain removability, weather (light) resistance, chemical resistance, water resistance, appearance and the like. Can be formed with a single coating operation, and even in areas where UV irradiation is insufficient it can be sufficiently cured, and has high environmental conservation and safety, making it suitable for coating automobiles and structures. It was made for the purpose of providing a coating composition to be used.

[0004]

Means for Solving the Problems As a result of intensive studies to develop a coating composition having the above-mentioned excellent properties, the present inventors have found that a specific resin, a polyisocyanate compound, a specific ultraviolet-curable compound and Contains a functional (meth) acrylate, a specific ceramic component, a light stabilizer and a photopolymerization initiator,
And it has been found that the composition can be achieved by the composition in which the contents of the UV-curable polyfunctional (meth) acrylate and the ceramic component are in the respective specific ranges,
The present invention has been completed based on this finding. That is, the present invention comprises the following items. (1) (A) A glass transition temperature of 50 to 120 ° C. obtained by polymerizing a monomer having a polymerizable double bond, a number average molecular weight of 3,000 to 100,000, and a hydroxyl value of 50 to 150 mg KO.
Resin having H / g and acid value of 1 to 25 mgKOH / g, (B) polyisocyanate compound having two or more isocyanate groups and / or blocked isocyanate groups in one molecule, (C)
From UV-curable polyfunctional (meth) acrylates having two or more (meth) acryloyl groups in one molecule and a number average molecular weight of 190 to 2,000, (D) aluminum, silicon, zirconium and antimony oxide sols It contains at least one selected dispersion, (E) light stabilizer, and (F) photopolymerization initiator, and the content of component (C) is (A),
20-80% by weight based on the total weight of components (B) and (C)
The coating composition, wherein the solid content of the component (D) is 5 to 60% by weight based on the weight of the total solid content. (2) The resin of the component (A) is (a) an ester of (meth) acrylic acid of an alkyl alcohol having 1 to 12 carbon atoms of 10 to 8
9% by weight, (b) 10 to 50% by weight of a hydroxyl group-containing monomer having a polymerizable double bond, (c) 0.1 to 10% by weight of a carboxyl group-containing monomer having a polymerizable double bond,
(d) Styrene 0 to 15% by weight, (e) acrylonitrile 0
The coating composition according to item (1), which is obtained by copolymerizing a monomer mixture consisting of 10 to 10% by weight and (f) 0 to 10% by weight of another monomer. (3) Item (1) or (2), wherein the molar ratio of the isocyanate group and / or the blocked isocyanate group in the component (B) to the hydroxyl group in the component (A) is 0.6 to 1.6. Coating composition. (4) The coating composition according to any one of (1) to (3), wherein the component (C) contains a polyfunctional (meth) acrylate having three or more (meth) acryloyl groups in one molecule. (5) Component (D) is a dispersion of silicon oxide sol (1)
~ The coating composition according to the item (4). (6) The coating composition according to item (5), wherein the silicon oxide sol is surface-modified with a silane coupling agent. (7) The coating composition according to any one of (1) to (6), wherein the light stabilizer as component (E) is at least one selected from hindered amine antioxidants and benzotriazole ultraviolet absorbers. . (8) The coating composition according to any one of (1) to (7), wherein the photopolymerization initiator of the component (F) is an acetophenone compound. (9) After dispersion-stabilizing the component (D) in the polymerization solvent,
By polymerizing the resin of component (A), or
(D) Component dispersion-stabilized resin solution obtained by polymerizing the component resin and then stabilizing dispersion of the (D) component in this resin solution with or without heating. The coating composition according to any one of (1) to (8).

The present invention will be described in detail below. The resin used as the component (A) in the composition of the present invention needs to have a glass transition temperature in the range of 50 to 120 ° C. When the glass transition temperature is less than 50 ° C, the obtained coating film has insufficient hardness and it is difficult to obtain a high weather resistance, and when it exceeds 120 ° C, workability during coating is deteriorated. The appearance of the obtained coating film is deteriorated such as sharpness and gloss. Further, by adjusting the glass transition temperature within the above range, the low stain removability which is a drawback of the coating composition proposed in JP-A-4-173882 is improved. From the viewpoint of hardness, appearance, stain removability, workability, etc. of the coating film, the preferable glass transition temperature is 50 to 100 ° C.
Is the range. Further, the resin has a number average molecular weight of 3,
It is necessary to be in the range of 000 to 100,000. When the number average molecular weight is less than 3,000, the weather resistance of the resulting coating film is insufficient, and when it exceeds 100,000, workability during coating is deteriorated. From the viewpoint of the weather resistance and workability of the coating film, the number average molecular weight is 4,000 to 70,000.
Is preferable, and a range of 4,500 to 40,000 is particularly preferable. The hydroxyl value is 50-150 mgKOH /
It must be in the range of g. Hydroxyl value is 50 mg KO
When it is less than H / g, the resulting coating film has insufficient crosslink density, and it is difficult to obtain high stain resistance and high stain removal property. When it exceeds 150 mgKOH / g, the coating film has a dense structure. Too much, the contraction stress at the time of forming the coating film becomes large, it becomes impossible to relax, and cracks and the like are likely to occur in the coating film. The hydroxyl value is 50 to 120 mgKOH from the viewpoints of the stain resistance of the coating film, the stain removal property, and the suppression of crack generation.
The range of / g is preferable. On the other hand, the acid value is 1 to 25 mgKOH /
It must be in the range of g. Acid value is 1mgKOH / g
If it is less than 25%, the curability of the part where the ultraviolet irradiation is not uniform is remarkably lowered, and if it exceeds 25 mgKOH / g, the storage stability and pot life of the paint tend to be extremely lowered. From the viewpoint of curability, stability of paint, pot life, etc., the acid value is preferably in the range of 2 to 10 mgKOH / g. In the present invention, the resin as the component (A) is (a) having 1 to 1 carbon atoms.
(2) a (meth) acrylic acid ester of an alkyl alcohol, (b) a hydroxyl group-containing monomer having a polymerizable double bond, and (c) a carboxyl group-containing monomer having a polymerizable double bond as essential components Further, those obtained by copolymerizing (d) styrene, (e) acrylonitrile, and (f) other monomers, if necessary, are preferable. The (meth) acrylic acid ester of an alkyl alcohol having 1 to 12 carbon atoms (hereinafter referred to as “acrylic ester”) of the component (a) used as an essential monomer component is 10 based on the weight of all monomers. It is desirable to use at a ratio of ~ 89% by weight.
The acrylic ester is an essential component for controlling the glass transition temperature of the coating film, and when the number of carbon atoms of the alkyl group of the alcohol portion exceeds 12, the glass transition temperature of the obtained resin tends to be too low. Can be seen. If the amount of the ester used is less than 10% by weight,
The glass transition temperature of the resulting resin cannot be raised to 50 ° C or higher unless other low-polymerizable monomer is used, and if a low-polymerizable monomer is used, the weather resistance of the coating film is significantly reduced. To do. On the other hand, if it exceeds 89% by weight, the required amount of hydroxyl groups or carboxyl groups cannot be introduced into the resin, and it is difficult to obtain a coating film having high weather resistance, high stain resistance, and high stain removability. In order to obtain a coating film having desired desired physical properties, the amount of the acrylic ester used is preferably 50 to 89% by weight.

The alkyl alcohol having 1 to 12 carbon atoms forming the acrylic ester as the component (a) may be any of alcohols having a linear, branched or cyclic alkyl group. Examples of the acrylic ester as the component (a) include methyl (meth) acrylate, ethyl (meth) acrylate, -n-propyl (meth) acrylate, and (meth).
Isopropyl acrylate, n-butyl (meth) acrylate, isobutyl (meth) acrylate, t-butyl (meth) acrylate, pentyl (meth) acrylate, hexyl (meth) acrylate, (meth) acrylic acid Examples thereof include cyclohexyl, 2-ethylhexyl (meth) acrylate, adamantyl (meth) acrylate, dodecyl (meth) acrylate, and isobornyl (meth) acrylate. These may be used alone or in combination of two or more. Next, the hydroxyl group-containing monomer having a polymerizable double bond of the component (b) used as an essential monomer component is used in a proportion of 10 to 50% by weight based on the weight of the total monomer. Is desirable. If the amount used is less than 10% by weight,
It is not possible to introduce the necessary crosslinking points into the resin obtained,
A coating film having high weather resistance, high stain resistance, and high stain removability cannot be obtained. On the other hand, if it exceeds 50% by weight, the crosslinking density of the coating film becomes too high, or unreacted hydroxyl groups remain in the resin during the crosslinking reaction between the resin obtained and the component (B), This causes deterioration of the water resistance and moisture resistance of the film, and eventually the weather resistance of the coating film. In order to introduce an appropriate number of crosslinking points into the resin and obtain a coating film having desired desired physical properties, the amount of the monomer as the component (b) used is preferably in the range of 10 to 30% by weight. Examples of the monomer as the component (b) include hydroxyethyl (meth) acrylate, hydroxypropyl (meth) acrylate, hydroxybutyl (meth) acrylate, 1,4-butanediol mono (meth) acrylate, and hydroxyethyl (meth). ) Ε-caprolactone adduct of acrylate, ethylene oxide and propylene oxide adduct of hydroxyethyl (meth) acrylate, and the like. These may be used alone or in combination of two or more. Further, the carboxyl group-containing monomer having a polymerizable double bond of the component (c) used as an essential monomer component is
It is preferably used in a proportion of 0.1 to 10% by weight based on the weight of all monomers. If the amount used is less than 0.1% by weight, the acid value of the resin obtained will be too small, and the curability of the non-uniform areas of UV irradiation will be significantly reduced. If it exceeds 10% by weight, the paint will be stored. Stability and pot life tend to be significantly reduced. From the viewpoints of curability, storage stability of paint, pot life, etc., the preferable amount of component (c) used is in the range of 0.1 to 5% by weight, particularly 0.1.
A range of ˜3% by weight is preferred. Examples of the monomer as the component (c) include (meth) acrylic acid, itaconic acid, mesaconic acid, maleic acid, fumaric acid, ω-carboxy-polycaprolactone (n = 2) monoacrylate [for example, Aronix M- 5300 [manufactured by Toagosei Chemical Industry Co., Ltd.],
Phthalic acid monohydroxyethyl acrylate [eg,
Aronix M-5400 [Toagosei Chemical Industry Co., Ltd.
]], Acrylic acid dimer [eg Aronix M
-5600 [manufactured by Toagosei Chemical Industry Co., Ltd.] and the like. These may be used alone or in combination of two or more.

Further, the styrene as the component (d) is not an essential component, and is used if necessary for the purpose of improving the appearance of the coating film such as the clarity. When styrene is used, it is preferably used in a proportion of 15% by weight or less based on the total weight of the monomers. If the amount of styrene used exceeds 15% by weight, the weather resistance, stain resistance, and stain removability of the resulting coating film tend to deteriorate. From the standpoint of the balance of appearance such as clearness of coating film, weather resistance, stain resistance, and stain removability, the preferable amount of styrene used is 1 to 1.
It is in the range of 0% by weight. In addition, the acrylonitrile as the component (e) is not an essential component, and is used as necessary for the purpose of improving the adhesion of the coating film to the substrate and the impact resistance. When acrylonitrile is used, it is preferably used in a proportion of 10% by weight or less based on the total weight of the monomers. If the amount of acrylonitrile used exceeds 10% by weight, the weather resistance, stain resistance, and stain removability of the coating film tend to deteriorate. From the viewpoint of the balance of adhesion of the coating film to the substrate, impact resistance, weather resistance, stain resistance, stain removability, etc., the preferable amount of acrylonitrile used is in the range of 1 to 5% by weight. Next, the other monomer of the component (f) is not an essential component, and in designing the coating film,
It is appropriately selected and used depending on the base material, the purpose of use, and the like. When other monomers are used, it is desirable to use them in a proportion of 10% by weight or less based on the total weight of the monomers. When the amount used exceeds 10% by weight, it is difficult to obtain a coating film having desired physical properties. Examples of the other monomer of the component (f) include phosmer [manufactured by Unichemical Co.], glycidyl (meth) acrylate, allyl (meth) acrylate, 3,4-epoxycyclohexylmethyl (meth) acrylate, (meth ) Phenyl acrylate, α-methylstyrene, p-vinyltoluene, (meth) acrylamide, N, N-dimethyl (meth) acrylamide, (meth) acrylic acid-1,2,2,6,6-pentamethyl-4-
Piperidyl, (meth) acrylic acid-2,2,6,6-tetramethyl-4-piperidyl, ethyl vinyl ether, isopropyl vinyl ether, n-propyl vinyl ether, n-butyl vinyl ether, isobutyl vinyl ether, 2-ethylhexyl vinyl ether, cyclohexyl vinyl ether, etc. Aliphatic vinyl ether compounds, and further 2,3-dihydrofuran, 3,4-dihydro-2H-pyran, trimethoxysilylpropyl (meth)
Examples thereof include acrylate, maleic anhydride, itaconic anhydride, maleic acid esters, and fumaric acid esters. These may be used alone or in combination of two or more. The resin as the component (A) is obtained by copolymerizing a monomer mixture composed of these monomers. The polymerization method at this time is not particularly limited, and known methods such as solution polymerization in an organic solvent, suspension polymerization, emulsion polymerization, bulk polymerization, and precipitation polymerization can be used. Further, the polymerization method is not particularly limited, and for example, radical polymerization, cationic polymerization, and anionic polymerization can be used, and among these, radical polymerization is preferable from the industrial viewpoint. Examples of the polymerization initiator used in radical polymerization include t-
Butyl hydroperoxide, cumene hydroperoxide, t-butyl peroxyneodecanate, t-butyl peroxypivalate, t-hexyl peroxy-2
-Organic peroxides such as ethylhexanoate and methylethylketone peroxide, or 2,2'-azobis (2,4-dimethylvaleronitrile), 2,2'-azobis (2-methylpropionitrile) (AIBN) 2,
Azo initiators such as 2'-azobis (2-methylbutyronitrile) can be mentioned. Of course, it is not limited to these. These radical polymerization initiators may be used alone or in combination of two or more.

Generally, the polymerization temperature is preferably in the range of 60 to 150 ° C. If the polymerization temperature is lower than 60 ° C., the radical polymerization initiator is hard to decompose and the reaction is hard to proceed,
When the temperature exceeds 150 ° C., even if the radical polymerization initiator is decomposed by heat to generate radicals, the life of the radical polymerization initiator is short, and it is difficult for the growth reaction to proceed effectively. The polymerization time cannot be generally determined depending on the polymerization temperature and other conditions, but generally 2 to 6 hours is sufficient. In the composition of the present invention, a polyisocyanate compound containing two or more isocyanate groups and / or blocked isocyanate groups in one molecule is used as the curing agent of the component (B). Examples of such polyisocyanate compounds include compounds called isocyanate monomers such as hexamethylene diisocyanate, isophorone diisocyanate, tolylene diisocyanate, diphenylmethane diisocyanate, xylylene diisocyanate, dicyclohexylmethane-4,4'-diisocyanate, and biuret thereof. Body, isocyanurate body, polyisocyanate derivative such as trimethylolpropane adduct body,
Further, the above-mentioned isocyanate monomers and polyisocyanate derivative blocks are preferable.
These polyisocyanate compounds may be used alone or in combination of two or more. In the composition of the present invention, the UV-curable polyfunctional (meth) acrylate used as the component (C) has a number average molecular weight of 190 to 20 which has two or more (meth) acryloyl groups in one molecule.
2,000 compounds. A compound having one (meth) acryloyl group in one molecule has insufficient curability. Further, if the number average molecular weight is less than 190, the flexibility of the obtained coating film will be poor, and if it exceeds 2,000, the curability will be insufficient and the appearance of the coating film will be poor. Examples of such polyfunctional (meth) acrylates include 1,3-
Butanediol di (meth) acrylate, diethylene glycol di (meth) acrylate, polyethylene glycol di (meth) acrylate, hydroxypivalic acid neopentyl glycol ester di (meth) acrylate, trimethylolpropane tri (meth) acrylate, pentaerythritol tetra (meth) ) In addition to polyvalent esters of (meth) acrylic acid with polyhydric alcohols such as acrylate and dipentaerythritol hexa (meth) acrylate, n moles of adipic acid, (n + 1) moles of hexanediol and 2 moles of (meth) Polyester (meth) acrylate synthesized with acrylic acid, epoxy (meth) acrylate obtained by esterifying epoxy group of alicyclic epoxy compound with (meth) acrylic acid, hexamethylene diisocyanate With hydroxy group (meth)
Polyurethane (meth) acrylate reacted with acrylate (for example, hydroxyethyl acrylate),
Examples thereof include melamine (meth) acrylate obtained by reacting a methylol group of methylol melamine with hydroxyethyl (meth) acrylate. These may be used alone or in combination of two or more. Among these, those having 3 or more (meth) acryloyl groups in one molecule are preferable from the viewpoint of curability.

The above-mentioned component (A) and (B) in the composition of the present invention
Regarding the mixing ratio of the component and the component (C), the amount of the component (C) is 20 to 8 based on the total weight of the components (A), (B) and (C).
It is necessary to mix each component so that the content becomes 0% by weight. When the blending amount of the component (C) is less than 20% by weight,
The coating film is inferior in clarity, and it is difficult to obtain a coating film with a high film thickness by one coating operation. When it exceeds 80% by weight, the curing shrinkage strain of the coating film becomes large and the adhesion is deteriorated. Unfavorable situations such as deterioration of weather resistance. From the viewpoint of the balance of clearness of the coating film, increase in film thickness, adhesion, weather resistance, etc., the preferable amount of the component (C) is the total weight of the components (A), (B) and (C). Based on this, the range is 30 to 70% by weight. Further, the polyisocyanate compound of the component (B) has a molar ratio of the isocyanate group and / or the blocked isocyanate group in the polyisocyanate compound to the hydroxyl group in the resin of the component (A) of 0.6 to 1.6. It is preferable to mix them in such a range. When this molar ratio is less than 0.6, some of the hydroxyl groups in the resin remain unreacted during the cross-linking reaction between the polyisocyanate compound of component (B) and the resin of component (A). This causes the water resistance and moisture resistance of the coating film to decrease, which in turn causes the weather resistance of the coating film to deteriorate. On the other hand, when the molar ratio exceeds 1.6, the isocyanate groups and / or blocked isocyanate groups remain unreacted, and in this case also the water resistance and moisture resistance of the coating film decrease, and by extension the water resistance of the coating film. Cause worse. From the viewpoint of coating film physical properties, the preferred molar ratio is 0.1.
The range is 8 to 1.2. In the composition of the present invention,
As the ceramic component of the component (D), at least one dispersion selected from oxide sols of aluminum, silicon, zirconium and antimony is used. These oxide sols are generally supplied as an aqueous dispersion, and in the case of an aqueous dispersion, if the coating composition is aqueous, it can be used as it is, but if it is an organic solvent system, it is desirable. The organic solvent may be used after phase conversion. As a method of this phase conversion, for example, a method of adding a water-soluble organic solvent to an aqueous dispersion and repeating the operation of distilling off water to perform a phase conversion in a desired organic solvent is used. You can Among the oxide sol dispersions, the silicon oxide sol dispersion is preferable because it can be easily surface-modified with a silane coupling agent. Since the dispersion of the surface-modified silicon oxide sol can introduce various functional groups on the particle surface thereof, when it is used in the composition of the present invention, it does not react chemically with organic components such as resins and polyisocyanate compounds. Easy to join. In this way, when the ceramic component and the organic component are chemically bonded, the cross-linking of the coating film becomes stronger and the stain resistance, stain removability, weather resistance and the like are improved as compared with the case where they are not chemically bonded. As a dispersion of silicon oxide sol, for example, as an aqueous dispersion, Snowtex-O [Nissan Chemical Industry Co., Ltd.
Made, product name] and Snowtex-N [Nissan Chemical Industry Co., Ltd.]
Manufactured by Nissan Chemical Industry Co., Ltd. as an organic solvent dispersion, Snowtex MIBK-ST
And so on. In the composition of the present invention, one kind of the oxide sol dispersion may be used, or two or more kinds thereof may be used in combination. , Relative to the total solids of the coating composition, 5
It is necessary to select it so as to be ˜60% by weight. When the solid content of the oxide sol dispersion is less than 5% by weight based on the total solid content, the effect of adding the oxide sol dispersion is not sufficiently exerted, resulting in stain resistance of the coating film and decontamination. The effect of improving the properties and weather resistance is not recognized so much, and if it exceeds 60% by weight, the flexibility of the coating film tends to decrease. The solid content of the dispersion of the oxide sol is preferably in the range of 10 to 60% by weight from the viewpoint of the balance of the stain resistance, stain removal resistance, weather resistance, flexibility of the coating film. .

In the composition of the present invention, the light stabilizer used as the component (E) is for improving the weather resistance of the coating film. Examples of such a light stabilizer include compounds that dissolve or uniformly disperse in the coating film, do not cause curing inhibition during ultraviolet curing, and do not yellow the coating film, for example, ultraviolet absorbers and antioxidants. Is appropriately selected from here,
Examples of the UV absorber include benzophenone-based, phenyl salicylate-based, and benzotriazole-based UV absorbers. Among them, benzotriazole-based UV absorbers are particularly preferable from the viewpoint of effects. Further, as the antioxidant, a hindered amine-based antioxidant is particularly preferable from the viewpoint of effect. One of these light stabilizers may be used, or two or more thereof may be used in combination.
The compounding amount is the total amount 1 of the components (A), (B) and (C).
It is generally selected in the range of 0.5 to 5 parts by weight with respect to 00 parts by weight. In the composition of the present invention, the photopolymerization initiator used as the component (F) is a compound having absorption in the ultraviolet region of 260 to 450 nm, specifically, a benzophenone compound, an acetophenone compound, Michler's ketone,
Examples thereof include benzyl compounds, tetraalkyl thiuram monosulfide, thioxane compounds, and of these, acetophenone compounds are particularly preferable from the viewpoint of effects. The photopolymerization initiators may be used alone or in combination of two or more, and the blending amount thereof is
It is generally selected in the range of 0.5 to 5 parts by weight based on 100 parts by weight of the total amount of the components (A), (B) and (C). The method for preparing the coating composition of the present invention is not particularly limited, and various methods can be used, but the following method is preferable because the coating composition can be efficiently prepared. That is, by dispersing and stabilizing the dispersion of the oxide sol of the component (D) in a polymerization solvent, polymerizing the resin of the component (A) under the same polymerization conditions as described above, or the component (A) After polymerizing the resin, the oxide sol dispersion-stabilized resin solution is prepared by stabilizing the dispersion of the oxide sol in the resin solution with or without heating. Due to (A) component resin,
The coating composition of the present invention can be prepared by homogeneously mixing the component (B), the component (C), the component (E), the component (F) and optionally various additives. As various additives used as desired, for example,
Photosensitizers for photopolymerization reactions such as tin compounds and zinc compounds that are commonly used as reaction catalysts for hydroxyl groups and isocyanate groups, amine compounds, urea compounds, and sulfur compounds that are commonly used for UV-curable coatings, and polymerization curing A colorant such as an organic peroxide, a pigment, a dye, a glass flake, an aluminum flake, and a mica flake for further uniformly performing a filler, a solvent, a pigment dispersant,
A flow regulator, a leveling agent, an anti-gelling agent and the like can be mentioned. The coating composition of the present invention thus obtained,
In addition to paints, it can also be used in inks, adhesives, molded products and the like. The coating method of the coating composition of the present invention is not particularly limited and can be appropriately selected and used from methods such as roller coating, brush coating, roll coater, spray coating and electrostatic coating. The coating composition of the present invention may be cured by irradiating it with ultraviolet rays after coating, and at that time, if necessary, preheating for removing the solvent before irradiating with ultraviolet rays or irradiating with ultraviolet rays. After that, additional heating can be performed. Further, the ultraviolet irradiation device is preferably one capable of irradiating the surface of the three-dimensional object as uniformly as possible, and a high pressure mercury lamp, a metal halide lamp or the like can be used as the ultraviolet source.

[0011]

The present invention will be described in more detail with reference to the following examples, but the present invention is not limited to these examples. Preparation of coating film test pieces and evaluation of coating film performance were performed as follows. (1) Preparation of coating film test piece Baking epoxy resin paint [Epico Primer No. 1000 BF2, on a polished steel plate (JIS G 3141)]
Nippon Oil & Fats Co., Ltd.] was applied to a dry film thickness of 20 μm, and then baked at 160 ° C. for 20 minutes. Then
On top of that, urethane resin paint [High Urethane No. 50
00 (white), manufactured by NOF CORPORATION, and a curing agent [high urethane curing agent HA, manufactured by NOF CORPORATION] at a weight ratio of 5: 1 to obtain a dry film thickness of 25 μm. Then, it was forcibly dried at 80 ° C. for 30 minutes. Next, each coating material of Examples 1 to 7 and Comparative Examples 1 to 6 was spray coated on the coated surface so that the dry film thickness was a predetermined film thickness, and the coating was set at room temperature for 10 minutes. After that, in the case of using the paints of Examples 1, 3 to 6 and Comparative Examples 1 to 4, a far infrared heater [Inflation Stein manufactured by Nippon Insulators Co., Ltd.] was used so that the temperature of the article to be coated was 70 ° C. After heating for 5 minutes, high-pressure mercury lamp [Nippon Battery Co., Ltd., high cure lamp; length 2
0 cm, 3 balls, 4.8 kW] is evenly irradiated onto the surface of the coating object from a distance of 20 cm for 2 seconds, and after the irradiation of ultraviolet rays, the temperature of the coating object is further increased to 120 ° C. by a far infrared heater.
After heating for a minute, a coating film test piece was prepared. In addition, Example 2
In the case of using the paints of No. 7 and Comparative Examples 5 and 6, after heating the far-infrared heater [Inflation Stein, manufactured by Nippon Insulators Co., Ltd.] to 70 ° C. for 5 minutes,
Metal halide lamp [Nippon Battery]
Co., Ltd .; length 20 cm, 3 bulbs, 4.8 kW] was used for irradiation for 3 seconds to prepare a coating film test piece.

(2) Coating film performance Maximum film thickness: The maximum film thickness which gives a normal coating film in one coating operation when spray-coated on a test piece was expressed in μm. The normal coating film is a coating film in which no abnormalities such as dripping, running, foaming, etc. are observed during coating and subsequent curing treatment, and 60 μm or more was regarded as acceptable. Gloss retention: Dry film thickness of 6 according to the preparation of the coating film test piece
Regarding the coating film test piece spray-coated so as to have a thickness of 0 μm (however, 50 μm only in Comparative Example 2), JISK 540
The gloss retention rate (retention rate with respect to the initial gloss) after 1,000 hours of the sunshine weatherometer was calculated from 0.
In the following test, a coating film test piece prepared by the same method as the coating film test piece used for the gloss retention test was used. Image clarity: It was evaluated by visual observation according to the following criteria. ◯: When a fluorescent lamp is projected, it clearly appears. Δ: The periphery (outline) is slightly blurred when a fluorescent lamp is projected. X: When a fluorescent lamp is projected, the periphery (outline) is markedly blurred. Moisture resistance: The film was exposed for 240 hours at 40 ± 1 ° C. under a relative humidity of 95% or more, taken out, and after 2 hours, the surface condition was visually observed and evaluated according to the following criteria. ◯: There is no change in gloss and surface condition as compared with the original test piece. Δ: There are slight changes in gloss and swelling as compared with the original test piece. X: Significant change in gloss and swelling as compared with the original test piece. Xylene rubbing resistance: Rubbing the 100 reciprocating coating film surface with gauze impregnated with xylene, visually observing the change of the surface condition, and evaluating the xylene rubbing resistance according to the following criteria. ○: Compared with the original test piece, it was slightly glossy. Δ: Remarkably glossy compared with the original test piece. X: The substrate is exposed. Acid resistance: An acid resistance test was conducted according to JIS K 5400 8.22, and the acid resistance was evaluated according to the following criteria. ◯: There is no gloss change or discoloration as compared with the original test piece. Δ: There is a slight change in gloss and discoloration as compared with the original test piece. X: The gloss and color tone are greatly changed as compared with the original test piece. Alkali resistance: An alkali resistance test was conducted according to JIS K 5400 8.21, and alkali resistance was evaluated according to the following criteria. ◯: There is no gloss change or discoloration as compared with the original test piece. Δ: There is a slight change in gloss and discoloration as compared with the original test piece. X: The gloss and color tone are greatly changed as compared with the original test piece. Anti-magic stain resistance: Draw a line on the coating with oil-based magic,
After heating at 80 ° C. for 5 hours, the magic stain remaining on the surface of the coating film after wiping the magic with a gauze soaked with xylene was used to evaluate the magic stain resistance according to the following criteria. ○: The magic was completely wiped off and no trace was left. Δ: Traces of magic slightly remain. ×: The trace of magic remains sharp. Pencil hardness: determined according to JIS K 5400 8.4.2. Adhesion: An adhesion test was conducted according to JIS K 5400 8.5.1, and the adhesion was evaluated according to the following criteria. ○: 10 points. Δ: 8 points. X: 6 or less.

Production Example 1 A reaction vessel equipped with a stirrer, a thermometer, a reflux tube and a dropping funnel was charged with 50 parts by weight of xylene and 50 parts by weight of isobutyl acetate, heated and kept at 110 ° C. There,
65 parts by weight of methyl methacrylate, butyl acrylate 15
Parts by weight, 19 parts by weight of 2-hydroxyethyl methacrylate, 1 part by weight of methacrylic acid and 2 parts by weight of 2,2'-azobis (2-methylbutyronitrile) were mixed while maintaining a reflux state from the dropping funnel. It dripped over 2 hours.
After the dropping, keep the same temperature and continue stirring for 1 hour.
A mixture of 0.2 parts by weight of azobis (2-methylbutyronitrile) and 2 parts by weight of isobutyl acetate was added, and stirring was continued for another hour. After completion of the polymerization, a resin solution A-1 having a solid content of 50.1% by weight was obtained. Resin A-1 has a glass transition temperature of 60 ° C., a number average molecular weight of 4,800 and a hydroxyl value of 8
The acid value was 0 mgKOH / g and the acid value was 7 mgKOH / g. Production Examples 2 to 7 Resin solutions A-2 to A-7 were produced in the same manner as in Production Example 1 using the types and amounts of solvents, monomers and polymerization initiators shown in Table 1. The physical properties of the obtained resin are shown in Table 1.

[0014]

[Table 1]

[0015]

[Table 2]

[Note] 1) FM-2: ε-caprolactone modified hydroxyalkyl methacrylate 2) ABMBN: 2,2′-azobis (2-methylbutyronitrile) Reference Example 1 Stirrer, thermometer, reflux tube and dropping A reaction vessel equipped with a funnel was charged with 50 parts by weight of xylene and 50 parts by weight of isobutyl acetate, heated and maintained at 110 ° C. There,
Methyl methacrylate 50 parts by weight, butyl acrylate 30
Parts by weight, 19 parts by weight of 2-hydroxyethyl methacrylate, 1 part by weight of methacrylic acid and 2 parts by weight of 2,2'-azobis (2-methylbutyronitrile) were mixed while maintaining a reflux state from the dropping funnel. It dripped over 2 hours.
After the dropping, keep the same temperature and continue stirring for 1 hour.
A mixture of 0.2 parts by weight of azobis (2-methylbutyronitrile) and 2 parts by weight of isobutyl acetate was added, and stirring was continued for another hour. After the completion of the polymerization, a resin solution A-8 having a solid content of 50.2% by weight was obtained. The physical properties of the obtained resin were a glass transition temperature of 30 ° C., a number average molecular weight of 5,000, a hydroxyl value of 80 mgKOH / g and an acid value of 7 mgKOH / g. Examples 1 to 7 and Comparative Examples 1 to 6 Clear paints were prepared by uniformly mixing the components at the compounding ratios shown in Table 2.

[0017]

[Table 3]

[0018]

[Table 4]

[0019]

[Table 5]

[0020]

[Table 6]

[Note] 1) Hexamethylene diisocyanate polymer [Asahi Kasei Kogyo KK, trade name Duranate THA-100] 2) Hexamethylene diisocyanate polymer [Asahi Kasei KK, trade name Duranate 24A- 100] 3) Coronate HK50EX [Japan Polyurethane Industry
Co., Ltd., polymer of hexamethylene diisocyanate; isocyanate group content 10.2% by weight] 1,008 parts by weight, 348 parts by weight of 2-hydroxypropyl acrylate, 0.2 parts by weight of hydroquinone, and 0.1 parts by weight of triethylamine. Part was reacted at 80 ° C. for 10 hours to obtain a solution of a polyurethane acrylate having a number average molecular weight of 1,800 and a heating residue of 63% by weight. 4) Trimethylolpropane triacrylate (number average molecular weight 300) 5) Araldite XB-3084 [manufactured by Ciba Geigy,
Hydrogenated epoxy resin; epoxy equivalent 227] 450 parts by weight, 144 parts by weight of acrylic acid, 0.2 parts by weight of hydroquinone, 2 parts by weight of triethylamine and 200 parts by weight of xylene were reacted at 150 ° C. for 5 hours to obtain a number average molecular weight of 80.
75% by weight heating residue solution of 0 epoxy acrylate. 6) Polyethylene glycol diacrylate [NOF
Co., Ltd., trade name PEG400DA; number average molecular weight 52
0] 7) Organic solvent type silica sol [manufactured by Nissan Chemical Industries, Ltd., trade name MIBK-ST; heating residue 30% by weight] 8) Organic solvent type silica sol [manufactured by Nissan Chemical Industry Co., Ltd., trade name MIBK-ST] Silane coupling treatment obtained by reacting 1,000 parts by weight of the heating residue 30% by weight and 40 parts by weight of a silane coupling agent [Nippon Unicar Co., Ltd., trade name A-163] at 80 ° C. for 8 hours. A solution having a heating residue of 33% by weight of the prepared silica sol. 9) Hindered amine antioxidant [Sankyo Co., Ltd., trade name Sanol LS-292] 10) Benzotriazole ultraviolet absorber [Ciba Geigy Co., trade name Tinuvin 900] 11) Acetophenone photopolymerization initiator [Ciba Geigy Co. Manufactured by Irgacure 184] 12) acetophenone photopolymerization initiator [manufactured by Merck, trade name Darocur 1173] Next, a coating film test piece was prepared using this clear paint,
The coating film performance was evaluated. The evaluation results are shown in Table 3.

[0022]

[Table 7]

[0023]

[Table 8]

[0024]

[Table 9]

[0025]

[Table 10]

[0026]

The coating composition of the present invention contains a ceramic component, and a coating film having a high film thickness can be obtained by one coating operation, and the obtained coating film has weather resistance and stain resistance. It has excellent stain removability, and has good gloss, water resistance, and chemical resistance. Further, the coating composition of the present invention is sufficiently hardened even in a portion where the ultraviolet irradiation is insufficient, and has high environmental conservation and safety. The coating composition of the present invention having such excellent properties is particularly suitable for coating automobiles and structures.

─────────────────────────────────────────────────── ─── Continuation of front page (56) Reference JP-A-63-113085 (JP, A) JP-A-4-173882 (JP, A) (58) Fields investigated (Int.Cl. ⁷ , DB name) C09D 4/02 C09D 5/16 C09D 133/04 C09D 175/04

Claims (9)

(57) [Claims] 1. A glass transition temperature of 50 to 120 ° C. obtained by polymerizing (A) a monomer having a polymerizable double bond, a number average molecular weight of 3,000 to 100,000, and a hydroxyl value of 50 to 1
Resin with 50 mg KOH / g and acid value 1-25 mg KOH / g,
(B) Polyisocyanate compound having two or more isocyanate groups and / or blocked isocyanate groups in one molecule, (C) A number average molecular weight of 190 to 2,000 having two or more (meth) acryloyl groups in one molecule. UV curable polyfunctional (meth) acrylate, (D) at least one dispersion selected from oxide sols of aluminum, silicon, zirconium and antimony, (E) light stabilizer, and (F) light It contains a polymerization initiator, and the content of the component (C) is 20 to 80% by weight based on the total weight of the components (A), (B) and (C), and the solid content of the component (D). But,
The coating composition is 5 to 60% by weight based on the weight of the total solid content. 2. The resin as the component (A) is (a) an ester 1 of (meth) acrylic acid of an alkyl alcohol having 1 to 12 carbon atoms.
0 to 89% by weight, (b) 10 to 50% by weight of a hydroxyl group-containing monomer having a polymerizable double bond, and (c) 0.1 to 10% by weight of a carboxyl group-containing monomer having a polymerizable double bond. %, (D) styrene 0 to 15% by weight, (e) acrylonitrile 0 to 10% by weight, and (f) other monomers 0 to 10% by weight, which are obtained by copolymerization. The coating composition according to claim 1. 3. The (B) to the hydroxyl group in the component (A).
The molar ratio of the isocyanate group and / or the blocked isocyanate group in the component is 0.6 to 1.6.
The coating composition described. 4. The component (C) has a (meth) acryloyl group of 1
The coating composition according to any one of claims 1 to 3, which comprises a polyfunctional (meth) acrylate having 3 or more in the molecule. 5. The coating composition according to claim 1, wherein the component (D) is a dispersion of a silicon oxide sol. 6. The coating composition according to claim 5, wherein the silicon oxide sol is surface-modified with a silane coupling agent. 7. The coating composition according to claim 1, wherein the light stabilizer of the component (E) is at least one selected from hindered amine antioxidants and benzotriazole ultraviolet absorbers. 8. The coating composition according to claim 1, wherein the photopolymerization initiator as the component (F) is an acetophenone compound. 9. A dispersion-stabilizing component (D) in a polymerization solvent, and then polymerizing the resin as component (A), or
After polymerizing the resin of component (A), add (D) to the resin solution.
The coating composition according to any one of claims 1 to 8, which is prepared by using a dispersion-stabilizing resin solution of component (D) obtained by dispersion-stabilizing the components under heating or without heating.