JP2006131809A - Coating composition and article having hardened film of the coating composition - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a coating composition superior in storage stability which makes it possible to remove a stain by an oily pen, an oil and the like by a simple method such as a dry wiping by coating the metal surfaces of home electric products, kitchen products and the like, and plastic surfaces and the like, and which is for forming a coating film capable of maintaining its stain removing function for a long period of time; and an article having the hardened film of the coating composition. <P>SOLUTION: The coating composition comprises: a substrate resin comprising a copolymer which comprises 2-50 mass% of an organic solvent-soluble fluororesin having a radically polymerizable unsaturated bond through a urethane bond, 5-40 mass% of a one-side end radically polymerizable polysiloxane having a specified structural formula, 5-50 mass% of a radically polymerizable monomer having a hydroxyl group, and 0-70 mass% of a monomer having a functional group which is radically polymerizable with the above-mentioned components but does not react with others; and a hardening agent capable of cross-linkingly reacting with the substrate resin. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a coating composition having excellent storage stability and an article having a cured coating of the coating composition. More specifically, the present invention relates to an oily property by coating metal surfaces, plastic surfaces, etc. of household appliances and kitchen products. Coating composition excellent in storage stability for forming a coating film capable of removing contamination by pen, oil, etc. by a simple method such as dry wiping and maintaining the removal function for a long time, and the coating The present invention relates to an article having a cured film of the composition for use.

  By coating metal surfaces, plastic surfaces, and the like of home appliances and kitchen products with a coating composition, functions such as rust prevention and antibacterial properties can be imparted in addition to the beauty of the appearance. In addition, there is a stain resistant coating specification that is difficult to get dirty on the painted surface and can be easily wiped off even if it gets dirty. However, all of them have a problem that it is necessary to use thinner when wiping off, and that removability is poor.

  Therefore, with regard to facilitating removal of oil stains, there is a method for simplifying the removal of oil stains by applying a coating composition to which a lubricating material such as silicone oil, polyethylene wax, liquid paraffin or the like is added. Proposed. However, in coatings coated with a coating composition to which silicone oil, polyethylene wax, liquid paraffin, etc. are added, these additives bleed out over time, so that the function of removing oil stains is maintained over a long period of time. It is difficult. In addition, the compatibility between the coating composition and those additives is often poor, the transparency of the coating film is lowered, the beauty is impaired, and the surface may become sticky.

  In addition, a base resin in which (meth) acrylic acid ester is copolymerized using a polydimethylsiloxane compound capable of generating radicals such as azo group and peroxy group, and polydimethylsiloxane is arranged in a block type in the molecular chain has been proposed. (For example, refer to Patent Document 1). However, since polydimethylsiloxane compounds capable of generating radicals such as azo groups and peroxy groups are very expensive, the resin itself is very expensive. If the amount of the polydimethylsiloxane capable of generating radicals is reduced to make it cheaper, there is a drawback that the function of removing oil stains is lowered.

  As a means for solving the above problems, polydimethylsiloxane having radical polymerizable unsaturated bonds and other monomers are polymerized in the presence of an organic solvent-soluble fluororesin having radical polymerizable unsaturated bonds, and polydimethyl There has been proposed a base resin in which siloxane is arranged on the “leaf” portion of “trunk-branch-leaf” (see Patent Document 2). However, although such a base resin has good long-term maintainability of the contact angle of water and oil on the surface, it is still satisfactory from the viewpoint of long-term maintenance of the oil dirt removing function. It wasn't.

  Furthermore, (a) in the presence of a radically polymerizable fluororesin, one-end radically polymerizable polysiloxane, a monomer having an alkoxysilyl group, a monomer having a hydroxyl group, and substantially other than the above components and radical polymerization A coating composition comprising a base resin obtained by copolymerizing a monomer having a functional group that does not react with the base resin and (b) a curing agent capable of crosslinking reaction with the base resin has been proposed (see Patent Document 3). .) Although this coating composition is excellent in solving the above problems, it is not always satisfactory in terms of storage stability.

JP-A-9-100445 JP 2000-119354 A JP 2003-292870 A

  The present invention relates to metal surfaces such as home appliances and kitchen products, plastic surfaces, specifically, outer plates of electric devices such as microwave ovens, washing machines and refrigerators, kitchen range hoods, ventilation fans or automobiles, railway vehicles, etc. It is possible to remove the contamination with oil-based pens, oils, etc. by simple methods such as dry wiping, and to maintain the removal function for a long period of time. The object is to provide an excellent coating composition and an article having a cured coating of the coating composition.

The coating composition of the present invention comprises:
(A) 2-50% by mass of an organic solvent-soluble fluororesin having a radically polymerizable unsaturated bond via a urethane bond,
(B) General formula (1)

（式中、Ｒ¹、Ｒ²、Ｒ³、Ｒ⁴、Ｒ⁵及びＲ⁶はそれぞれ水素原子又は炭素原子数１〜１０の炭化水素基であり、それらは同一であっても異なっていてもよく、ｎは２以上の整数である。）
で示される片末端ラジカル重合性ポリシロキサン及び／又は一般式（２）

(Wherein R ¹ , R ² , R ³ , R ⁴ , R ⁵ and R ⁶ are each a hydrogen atom or a hydrocarbon group having 1 to 10 carbon atoms, and they may be the same or different. Well, n is an integer greater than or equal to 2.)
One-end radical polymerizable polysiloxane represented by the general formula (2)

（式中、Ｒ⁷、Ｒ⁸、Ｒ⁹、Ｒ¹⁰、Ｒ¹¹及びＲ¹²はそれぞれ水素原子又は炭素原子数１〜１０の炭化水素基であり、それらは同一であっても異なっていてもよく、ｐは０〜１０の整数であり、ｑは２以上の整数である。）
で示される片末端ラジカル重合性ポリシロキサン５〜４０質量％、
（Ｃ）水酸基を有するラジカル重合性単量体５〜５０質量％、及び
（Ｄ）上記の成分（Ａ）〜（Ｃ）とはラジカル重合するがその他の反応は生じない官能基を有する単量体０〜７０質量％
の共重合体からなる基体樹脂（ａ）、及び該基体樹脂（ａ）と架橋反応することが可能な硬化剤（ｂ）を含有することを特徴とする。

Wherein R ⁷ , R ⁸ , R ⁹ , R ¹⁰ , R ¹¹ and R ¹² are each a hydrogen atom or a hydrocarbon group having 1 to 10 carbon atoms, and they may be the same or different. Well, p is an integer of 0 to 10, and q is an integer of 2 or more.)
5 to 40% by mass of one-end radical polymerizable polysiloxane represented by
(C) a radically polymerizable monomer having a hydroxyl group of 5 to 50% by mass, and (D) a monomer having a functional group that undergoes radical polymerization with the above components (A) to (C) but does not cause other reactions. Body 0-70 mass%
And a curing agent (b) capable of undergoing a crosslinking reaction with the base resin (a).

  In the coating composition of the present invention, the component (D) is not an essential component, but the mass% representing the amount of each of the components (A) to (D) is (A) + ( B) The sum of (C) + (D), that is, mass% based on the total mass of the base resin (a).

  Moreover, the article | item which has a cured film of this invention is obtained by coat | covering with said coating composition and hardening this composition.

  The coating composition of the present invention has excellent storage stability, such as metal surfaces of household appliances and kitchen products, plastic surfaces, etc., specifically, outer plates of electric devices such as microwave ovens, washing machines and refrigerators, It is possible to paint kitchen range hoods, ventilation fans or automobiles, railway vehicles, other vehicles, etc., and remove contamination with oil-based pens, oils, etc. by a simple method such as wiping and maintaining the removal function for a long time. An article having the cured film of the present invention can be removed by a simple method such as dry wiping, and the removal function can be maintained for a long time. .

  The organic solvent-soluble fluororesin (A) having a radical polymerizable unsaturated bond via a urethane bond used for the preparation of the coating composition of the present invention has a hydroxyl group-containing fluororesin (A-1) and an isocyanate group. It is obtained by reacting with a radically polymerizable monomer (A-2). The reaction between the fluororesin having a hydroxyl group (A-1) and the radically polymerizable monomer having an isocyanate group (A-2) is carried out at room temperature to 80 ° C. in the absence of a catalyst or in the presence of a catalyst. be able to.

  Radical polymerizable monomer (A-2) having an isocyanate group per equivalent of hydroxyl group of the fluororesin (A-1) having a hydroxyl group, preferably in an amount ratio of 0.001 mol or more and less than 0.1 mol, preferably 0.01 The fluororesin (A-1) having a hydroxyl group and the radically polymerizable monomer (A-2) having an isocyanate group are reacted in an amount ratio of ˜0.08 mol. When the amount ratio of the radically polymerizable monomer (A-2) having an isocyanate group is less than 0.001 mol, graft copolymerization becomes difficult and the reaction mixture may become cloudy. Moreover, when it is 0.1 mol or more, gelation tends to occur during graft copolymerization, which is not preferable.

  The above-mentioned fluororesin (A-1) having a hydroxyl group preferably has a hydroxyl value of 5 to 250, more preferably 10 to 200, and still more preferably 20 to 150. When the hydroxyl value is less than 5, grafting is sufficient because the amount of the radically polymerizable monomer (A-2) having an isocyanate group to the fluororesin (A-1) having a hydroxyl group is reduced. The reaction mixture tends to become cloudy. Further, when the hydroxyl value is small, the hydroxyl value of the base resin (a) is also small, so that the oil stain removing function is lowered. On the other hand, when the hydroxyl value exceeds 250, the compatibility with the later-described one-end radical polymerizable polysiloxane (B) is deteriorated to cause phase separation, and graft copolymerization itself may not proceed.

  The fluororesin (A-1) having such a hydroxyl group can be prepared by a known method, but a commercially available product can also be used. As commercially available products, Lumiflon (registered trademark) LF-100, LF-200, LF-302, LF-400, LF-554, LF-600, LF-986N (manufactured by Asahi Glass Co., Ltd.), Cefral Coat (registered trademark) PX- 40, A606X, A202B, CF-803 (Central Glass Co., Ltd.), ZAFLON (registered trademark) FC-110, FC-220, FC-250, FC-275, FC-310, FC-575, XFC-973 ( Toagosei Co., Ltd.), Zeffle (registered trademark) GK-510 (manufactured by Daikin Industries, Ltd.), Fluonate (registered trademark) K-700, K-702, K-703, K-704, K-705 (Dainippon Ink Chemical Industries, Ltd.). These fluororesins (A-1) having a hydroxyl group may be used alone or in combination of two or more.

  Reaction product of diisocyanate (A-2-1) and radical polymerizable monomer (A-2-2) having a hydroxyl group as the above-mentioned radical polymerizable monomer (A-2) having an isocyanate group ( The reaction between the diisocyanate (A-2-1) and the radically polymerizable monomer (A-2-2) having a hydroxyl group can be carried out by a known method at a molar ratio of 1/1.), Methacryloyl isocyanate , 2-isocyanatoethyl methacrylate, and m- or p-isopropenyl-α, α-dimethylbenzyl isocyanate can be selected and used, preferably methacryloyl isocyanate, 2-isocyanatoethyl Select one or more of methacrylate and m- or p-isopropenyl-α, α-dimethylbenzyl isocyanate. It can be used in.

  Examples of the diisocyanate (A-2-1) include hexamethylene diisocyanate, isophorone diisocyanate, tolylene diisocyanate, xylylene diisocyanate, 1,3-bis (diisocyanatomethyl) cyclohexane, 1,3-bis (α, α-dimethylisocyanatomethyl) benzene, 4,4′-diphenylmethane diisocyanate, dicyclohexylmethane-4,4′-diisocyanate and the like can be mentioned, and these may be used alone or in combination of two or more. .

  Examples of the radical polymerizable monomer (A-2-2) having a hydroxyl group include 2-hydroxyethyl (meth) acrylate, 2-hydroxypropyl (meth) acrylate, and 3-hydroxypropyl (meth) acrylate. , 4-hydroxybutyl (meth) acrylate, p-hydroxystyrene, p-hydroxymethylstyrene, and the like. These may be used alone or in combination of two or more.

  In the preparation of the coating composition of the present invention, the organic solvent-soluble fluororesin (A) having a radically polymerizable unsaturated bond via a urethane bond is 2 to 50% by mass based on the mass of the base resin (a). Is used, preferably in the range of 5 to 40% by mass. When the amount of the organic solvent-soluble fluororesin (A) having a radically polymerizable unsaturated bond via a urethane bond is less than 2% by mass, the weather resistance when used as a coating film may be reduced. If it exceeds 50% by weight, gelation may occur during graft copolymerization.

  One-terminal radically polymerizable polysiloxane (B) used for the preparation of the coating composition of the present invention has the general formula (1)

（式中、Ｒ¹、Ｒ²、Ｒ³、Ｒ⁴、Ｒ⁵及びＲ⁶はそれぞれ水素原子又は炭素原子数１〜１０の炭化水素基であり、例えばメチル基、エチル基、プロピル基、ブチル基、ペンチル基、ヘキシル基、フェニル基、又はシクロヘキシル基であり、それらは同一であっても異なっていてもよいが、Ｒ¹は好ましくは水素原子又はメチル基であり、Ｒ²、Ｒ³、Ｒ⁴、Ｒ⁵は好ましくはそれぞれメチル基又はフェニル基であり、Ｒ⁶は好ましくはメチル基、ブチル基又はフェニル基であり、ｎは２以上の整数であり、好ましくは１０以上の整数であり、より好ましくは３０以上の整数である。）
及び／又は一般式（２）

(Wherein R ¹ , R ² , R ³ , R ⁴ , R ⁵ and R ⁶ are each a hydrogen atom or a hydrocarbon group having 1 to 10 carbon atoms, for example, a methyl group, an ethyl group, a propyl group, a butyl group) Group, pentyl group, hexyl group, phenyl group, or cyclohexyl group, which may be the same or different, R ¹ is preferably a hydrogen atom or a methyl group, R ² , R ³ , R ⁴ and R ⁵ are preferably each a methyl group or a phenyl group, R ⁶ is preferably a methyl group, a butyl group or a phenyl group, and n is an integer of 2 or more, preferably an integer of 10 or more. More preferably, it is an integer of 30 or more.)
And / or general formula (2)

（式中、Ｒ⁷、Ｒ⁸、Ｒ⁹、Ｒ¹⁰、Ｒ¹¹及びＲ¹²はそれぞれ水素原子又は炭素原子数１〜１０の炭化水素基であり、例えばメチル基、エチル基、プロピル基、ブチル基、ペンチル基、ヘキシル基、フェニル基、又はシクロヘキシル基であり、それらは同一であっても異なっていてもよいが、Ｒ⁷は好ましくは水素原子又はメチル基であり、Ｒ⁸、Ｒ⁹、Ｒ¹⁰、Ｒ¹¹は好ましくはそれぞれメチル基又はフェニル基であり、Ｒ¹²は好ましくはメチル基、ブチル基又はフェニル基であり、ｐは０〜１０の整数であり、好ましくは３であり、ｑは２以上の整数であり、好ましくは１０以上の整数であり、より好ましくは３０以上の整数である。）
で示される。

(Wherein R ⁷ , R ⁸ , R ⁹ , R ¹⁰ , R ¹¹ and R ¹² are each a hydrogen atom or a hydrocarbon group having 1 to 10 carbon atoms, for example, a methyl group, an ethyl group, a propyl group, or a butyl group. Group, pentyl group, hexyl group, phenyl group, or cyclohexyl group, which may be the same or different, R ⁷ is preferably a hydrogen atom or a methyl group, R ⁸ , R ⁹ , R ¹⁰ and R ¹¹ are each preferably a methyl group or a phenyl group, R ¹² is preferably a methyl group, a butyl group or a phenyl group, p is an integer of 0 to 10, preferably 3, and q Is an integer of 2 or more, preferably an integer of 10 or more, more preferably an integer of 30 or more.)
Indicated by

  Such a one-terminal radical polymerizable polysiloxane (B) can be prepared by a known method, but a commercially available product can also be used. As commercially available products, Silaplane (registered trademark) FM-0711 (number average molecular weight 1,000), FM-0721 (number average molecular weight 5,000), FM-0725 (number average molecular weight 10,000) (above, Chisso Corporation Company-made), X-22-174DX (number average molecular weight 4,600, manufactured by Shin-Etsu Chemical Co., Ltd.), and the like. These single terminal radically polymerizable polysiloxanes (B) may be used alone or in combination of two or more.

  In the preparation of the coating composition of the present invention, the one-terminal radical polymerizable polysiloxane (B) is in the range of 5 to 40% by mass, preferably in the range of 10 to 30% by mass, based on the mass of the base resin (a). Used in. When the amount of the one-end radical polymerizable polysiloxane (B) used is less than 5% by mass, the oil dirt removing function is insufficient and / or the maintenance of the oil dirt removing function is deteriorated, resulting in 40% by mass. In the case of exceeding, the cross-linking density per unit volume of the coating composition is lowered, so that oil pens, oil stains, etc. are likely to penetrate, resulting in insufficient initial oil stain removal function, In addition, the strength of the cured coating is lowered and the maintainability becomes insufficient.

  The radical polymerizable monomer (C) having a hydroxyl group used for the preparation of the coating composition of the present invention is not particularly limited as long as it has a hydroxyl group and a radical polymerizable double bond. Hydroxystyrene, p-hydroxymethylstyrene, 2-hydroxyethyl (meth) acrylate, 2-hydroxypropyl (meth) acrylate, 3-hydroxypropyl (meth) acrylate, 2-hydroxybutyl (meth) acrylate, 4-hydroxybutyl ( In addition to meth) acrylate, di-2-hydroxyethyl fumarate, polyethylene glycol or polypropylene glycol mono (meth) acrylate, or their ε-caprolactone adduct, Plaxel (registered trademark) FM to FA series (manufactured by Daicel Chemical Industries, Ltd.) , Capro Various α, β-ethylenically unsaturated carboxylic acid hydroxyalkyl esters such as (meth) acrylic acid, crotonic acid, maleic acid, fumaric acid, itaconic acid, citraconic acid, etc. Adduct of β-ethylenically unsaturated carboxylic acid and ε-caprolactone, or α, β-ethylenically unsaturated carboxylic acid and butyl glycidyl ether, phenyl glycidyl ether, Cardura (registered trademark) E (Shell Chemical Co., Ltd.) And an adduct with an epoxy compound. Among them, mainly from the viewpoint of adjusting Tg of the polymer, 2-hydroxyethyl (meth) acrylate, 2-hydroxypropyl (meth) acrylate, 3-hydroxypropyl (meth) acrylate, 2-hydroxybutyl (meth) acrylate, 4-hydroxy Butyl (meth) acrylate is preferably used. These radically polymerizable monomers (C) having a hydroxyl group may be used alone or in combination of two or more.

  In the preparation of the coating composition of the present invention, the radical polymerizable monomer (C) having a hydroxyl group is 5 to 50 mass based on the mass of the base resin (a) in order to achieve an oil stain removing function. %, Preferably 10 to 40% by mass. When the amount of the radically polymerizable monomer (C) having a hydroxyl group is less than 5% by mass, the initial oil stain removing function is lowered because the crosslinking density of the coating composition is insufficient, The strength and solvent resistance of the cured coating also decrease. On the other hand, when the amount exceeds 50% by mass, the amount of the curing agent (b) to be described later is inevitably increased, so that the hydrophilic portion per unit volume of the cured coating increases. If it exceeds 40% by mass, the crosslink density increases too much and the cured coating becomes brittle, or the base resin (a) becomes turbid by forming molecular micelles, which may deteriorate the appearance of the cured coating.

  In the preparation of the coating composition of the present invention, the ratio of component (A) to component (B) + (C) [(A) / ((B) + (C)), hereinafter abbreviated as base graft ratio. ] Is preferably in the range of 70/30 to 2/98. When the amount of component (A) increases and the base graft ratio exceeds 70/30, the amount of component (B) + (C) decreases as a result. , The oil dirt removal function tends to decrease. In addition, when the amount of component (A) is reduced and the base graft ratio is less than 2/98, the weather resistance and contact angle maintainability of the cured coating are lowered, and the oil stain removal function is maintained. There is a tendency to decrease.

  The monomer (D) having a functional group which is used for the preparation of the coating composition of the present invention and radically polymerizes with the above components (A) to (C) but does not cause any other reaction, undergoes radical polymerization. The one that reacts with the components (A) to (C) at the reaction temperature and reaction conditions is selected. Examples thereof include styrenes such as styrene, p-methylstyrene, p-chloromethylstyrene, vinyltoluene, methyl ( (Meth) acrylate, ethyl (meth) acrylate, n-propyl (meth) acrylate, i-propyl (meth) acrylate, n-butyl (meth) acrylate, i-butyl (meth) acrylate, tert-butyl (meth) acrylate, n-hexyl (meth) acrylate, cyclohexyl (meth) acrylate, 2-ethylhexyl (meth) acrylate, (Meth) acrylates having hydrocarbon groups such as ril (meth) acrylate, stearyl (meth) acrylate, isobornyl (meth) acrylate, adamantyl (meth) acrylate, phenyl (meth) acrylate, benzyl (meth) acrylate, and the like (Meth) acrylates substituted with hydrogen, fluorine, chlorine, bromine, or other atoms, vinyl acetate, vinyl benzoate, Veova (registered trademark) (made by Shell Chemical Co., Ltd., vinyl ester of branched monocarboxylic acid) Vinyl esters such as acrylonitrile, acrylonitrile such as methacrylonitrile, vinyl ethers such as ethyl vinyl ether, n-butyl vinyl ether, i-butyl vinyl ether, cyclohexyl vinyl ether, and the hydrogen atoms of which are fluorine, chlorine, bromine Vinyl ethers substituted with any of the above-mentioned atoms, acrylamides such as (meth) acrylamide, dimethyl (meth) acrylamide, diacetone acrylamide, acrylamides in which these hydrogen atoms are substituted with atoms such as fluorine, chlorine, bromine, glycidyl (meth) Epoxy group-containing vinyl compounds such as acrylate, 3,4-epoxycyclohexylmethyl (meth) acrylate, 3,4-epoxyvinylcyclohexane, olefins such as ethylene and propylene, vinyl chloride, vinylidene chloride, vinyl bromide, fluoride Examples include halogenated olefins such as vinyl, tetrafluoroethylene, chlorotrifluoroethylene, and other maleimides, vinyl sulfones, etc., and these are used in appropriate combination of two or more, but mainly from the viewpoint of copolymerizability. (Meth) acrylates are preferably used.

  On the other hand, as an unfavorable component (D), vinyl pyridine, N, N-dimethylaminoethyl (meth) acrylate, N, N-diethylaminoethyl (meth) acrylate, N, N-dimethyl (meth) acrylamide, 4 -Basic nitrogen-containing vinyl compounds such as (N, N-dimethylamino) styrene and N- {2- (meth) acryloyloxyethyl} piperidine, (meth) acrylic acid, angelic acid, crotonic acid, maleic acid, 4 Examples include acidic vinyl compounds such as vinyl benzoic acid, p-vinylbenzenesulfonic acid, 2- (meth) acryloyloxyethanesulfonic acid, and mono {2- (meth) acryloyloxyethyl} acid phosphate.

  In the preparation of the coating composition of the present invention, the component (D) is not an essential component for achieving the oil stain removing function, but in the range of 0 to 70% by mass based on the mass of the base resin (a). Use. If the amount of the component (D) used exceeds 70% by mass, the amount of binding of other components, particularly the component (C) for increasing the crosslinking density is lowered, so that the oil stain removing function or the maintenance thereof is insufficient. The component (D) is preferably used in combination so that the final base resin (a) has a Tg of 40 ° C. or higher. When the final substrate resin (a) has a Tg of less than 40 ° C., the coating composition after the coating composition has hardened, the Tg of the coating does not increase so much, and oil stains are removed when the cured coating is exposed to high temperatures. Function may be degraded.

  As the polymerization method for preparing the base resin (a) using each component described above, it is most convenient to use a solution radical polymerization method or a non-aqueous dispersion radical polymerization method among known polymerization methods. Recommended.

  As a solvent used in the polymerization, for example, aromatic hydrocarbons such as toluene, xylene, Solvesso (registered trademark) 100 (manufactured by Esso Petroleum Corporation), n-hexane, cyclohexane, octane, mineral spirit, kerosene, etc. Aliphatic, alicyclic hydrocarbons, esters such as ethyl acetate, n-butyl acetate, i-butyl acetate, butyl cellosolve acetate, methanol, ethanol, n-propanol, i-propanol, n-butanol, i-butanol, etc. And glycols such as ethylene glycol, propylene glycol, ethyl cellosolve, butyl cellosolve, and the like, and these may be used alone or in combination of two or more.

  The polymerization can be carried out by a conventional method using various known and commonly used radical polymerization initiators such as azo compounds or peroxides. The polymerization time is not particularly limited, but is usually selected industrially within a range of 1 to 48 hours. The polymerization temperature is usually 30 to 150 ° C, preferably 60 to 120 ° C. During the polymerization, a known and usual chain transfer agent such as butyl mercaptan, dodecyl mercaptan, α-methylstyrene dimer or the like can be added as necessary.

  The base resin (a) in the present invention suitably has a mass average molecular weight of about 5,000 to 200,000 in terms of polystyrene-equivalent GPC (gel permeation chromatography). If it is less than 5,000, the film-forming property, the weather resistance and the chemical resistance of the cured coating film tend to deteriorate, and as a result, the maintenance of the oil stain removing function is lowered, and 200,000 is added. When exceeding, it is not preferable because there is a risk of gelation during the polymerization.

  The curing agent (b) capable of cross-linking with the base resin (a) is appropriately selected from curing agents capable of reacting with the hydroxyl group of the base resin (a), and is generally known as a curing agent for acrylic curable paints. You can use what you have. Examples of such a curing agent include aniline aldehyde resin, urea resin, melamine resin, polyisocyanate, and blocked polyisocyanate. When the object to be coated is an electrical appliance, a kitchen product, or the like, generally surface hardness is often required. In such a case, a melamine resin is selected. The addition amount of the melamine resin is preferably 10 to 40 parts by mass, more preferably 15 to 30 parts by mass with respect to 100 parts by mass of the solid content of the base resin (a).

  The coating composition of the present invention can also contain other resins, for example, a fluororesin, an acrylic resin, a polyester resin, an alkyd resin, a silicone resin and the like as long as they do not impair the spirit of the present invention. Furthermore, the coating composition of the present invention may be various additives, for example, surfactants, extenders, color pigments, rust preventive pigments, fluororesin powders, silicone resins, as long as the purpose of the present invention is not impaired. Powders, rust inhibitors, dyes, waxes and the like can also be contained. However, in general, the inclusion of the additives described above reduces the cross-linking density per unit volume of the cured film, and lacquers and felt pens such as lacquer sprays and felt pens are more likely to penetrate, so that the oil stain removal function In order to ensure this, the amount of additive should be kept to the minimum necessary amount.

  In addition, the coating composition of the present invention can be applied by any known coating method, and the amount of the nonvolatile content is not particularly limited and can be appropriately selected, but is usually 30 to 50 masses. % Is preferable.

  In addition, the “article having a cured coating” of the present invention is obtained by coating the coating composition of the present invention and curing the composition, and is a product requiring a decontamination function. Although not particularly limited, it includes indoor and outdoor specifications such as outer plates of electric devices such as microwave ovens, washing machines, refrigerators, kitchen range hoods, ventilation fans, automobiles, railway vehicles, and other vehicles.

The present invention will be described below with reference examples, production examples, examples and comparative examples, but the present invention is not limited thereto. The commercial product names of the materials used in the following Reference Examples, Production Examples, Examples and Comparative Examples are shown below.
Fluororesin having a hydroxyl group (A-1): Cefalcoat (trademark) CF-803 (Central Glass Co., Ltd., hydroxyl value 60, number average molecular weight 15,000)
One-end radical polymerizable polysiloxane (B): Silaplane (registered trademark) FM-0721 (manufactured by Chisso Corporation, number average molecular weight 5,000)
Radical polymerization initiator: Perbutyl (registered trademark) O (t-butylperoxy-2-ethylhexanoate, manufactured by NOF Corporation)
Curing agent (b): Cymel (registered trademark) 303 (hexamethoxymethylol melamine, manufactured by Mitsui Cytec Co., Ltd.)

Reference Example 1 <Synthesis example of organic solvent-soluble fluororesin (A) having radically polymerizable unsaturated bond via urethane bond>
In a glass reactor equipped with a mechanical stirrer, thermometer, condenser and dry nitrogen gas inlet, 1,554 parts of cephalal coated CF-803, 233 parts of xylene and 6.3 parts of 2-isocyanatoethyl methacrylate And heated to 80 ° C. under a dry nitrogen atmosphere. After making it react at 80 degreeC for 2 hours and confirming that the absorption of the isocyanate of the sampling thing disappeared by the infrared absorption spectrum, the reaction mixture was taken out and the component (A) of 50 mass% of non volatile matters was obtained.

Production Examples 1 to 9 <Synthesis Example of Base Resin (a) and Comparative Resin>
In a glass reactor equipped with a mechanical stirrer, a thermometer, a condenser, and a dry nitrogen gas inlet, the amounts (parts by mass) shown in Table 1 of the component (A) synthesized in Reference Example 1 and n-acetate After adding butyl and heating to 90 ° C. in a nitrogen atmosphere, amounts (parts by mass) of methyl methacrylate (MMA), 2-ethylhexyl methacrylate (2-EMA), A mixture of hydroxyethyl methacrylate (2-HEMA), Silaplane (registered trademark) FM-0721, perbutyl O, γ-γ-methacryloxypropyltrimethoxysilane (γ-MTPMS) and xylene at the same temperature over 2 hours It was dripped. After maintaining at the same temperature for 2 hours, the amount (parts by mass) of perbutyl O shown in Table 1 is added, and further maintained at 90 ° C. for 5 hours, whereby the mass average molecular weight and nonvolatile content of the values shown in Table 1 are obtained. A solution of the base resin (a) having the above or a resin for a comparative example was obtained.

  In addition, Production Examples 1 to 3 are examples matched with the base resin (a), Production Example 4 is a case where the component (A) is not contained, and Production Examples 5 and 6 are the amounts of the component (B). This is a case outside the scope of the invention, Production Examples 7 and 8 are cases where the amount of component (C) is outside the scope of the present invention, and Production Example 9 is a case outside the scope of the present invention containing γ-MTPMS. is there.

Examples 1-3 and Comparative Examples 1-6
Acroze (registered trademark) # 6000 (white) (manufactured by Dainippon Paint Co., Ltd.), which is a one-component acrylic resin paint, is applied to an electrogalvanized steel sheet (50 × 150 mm) subjected to chromate treatment. The coating was applied to a dry film thickness of about 25 μm and baked at 150 ° C. for 20 minutes to form a white coating film. 20 parts by mass of Cymel 303 is added to 100 parts by mass of the solid content of those resins in the base resin (a) or the resin for the comparative example obtained in Production Examples 1 to 9, and the non-volatile content in the paint is 40% by mass. The composition for coating was prepared by diluting with n-butyl acetate so as to become, and coated on the white coating film, and further baked at 160 ° C. for 20 minutes to form a cured coating film.

The following characteristics were observed and measured for the steel sheet having each cured coating.
<Appearance of cured coating>
The presence or absence of abnormality of the cured film and the state of abnormality were visually confirmed.

<Oil stain removal (initial)>
On the surface of the cured coating, draw a line with black magic ink (registered trademark of Uchida Yoko Co., Ltd., felt pen from Teranishi Chemical Industry Co., Ltd.), dry at room temperature for 24 hours, wipe with a cloth, and evaluate as follows. Evaluated by criteria.
○: When no mark of Magic Ink (registered trademark) remains Δ: When a slight mark remains ×: When a mark remains clearly

<Oil stain removal (after exposure)>
Black magic ink (registered trademark) on the surface of the cured coating exposed for 600 hours in accordance with ISO 11341 method 1 outdoor (accelerated weathering test method of paint and varnish) using a Ci4000 sunshine weatherometer manufactured by ATLAS, using xenon as a light source ), The line was drawn and the solvent of Magic Ink (registered trademark) was sufficiently dried (after about 2 hours), and the surface was wiped dry in the same manner as described above and evaluated according to the same evaluation criteria as described above.

<Water repellency (initial, after exposure)>
Using a CA-W type automatic contact angle meter manufactured by Kyowa Interface Science Co., Ltd., about 5 μL of deionized water was placed on the cured coating, and the contact angle at this time was measured. 6 points were measured by changing the mounting position, the average value was calculated at 4 points excluding the smallest value and the largest value, and rounded to an integer value by rounding off. In addition, a cured film was exposed according to ISO 11341 method 1 outdoors (accelerated weathering test method for paints and varnishes) using a Ci4000 sunshine weatherometer manufactured by ATLAS, using xenon as a light source. The cured film was taken out every 100 hours up to 600 hours, and after sufficiently removing moisture, the contact angle was measured in the same manner as described above.

<Storage stability>
The sealed paint was left in a high-temperature bath at 50 ° C. for 20 days, and the change in viscosity was evaluated according to the following evaluation criteria.
○: No abnormality Δ: Tends to increase viscosity X: Tends to increase viscosity significantly
The results of the above observation and measurement were as shown in Tables 2 and 3 (water repellency, contact angle).

In Examples 1 to 3, good results were shown in all the evaluation items. However, in Comparative Example 1, although initial oil stain removability was good, there was a difficulty in maintaining oil stain removability after exposure, and the contact angle was also greatly reduced by exposure. In Comparative Example 2, the infiltration of contaminants was observed from the beginning, and the contact angle was also greatly reduced by exposure. In Comparative Example 3, bleeding of unreacted residual monomers was observed on the surface of the cured coating, and the surface was sticky, and the cross-linking density per unit volume of the cured coating was reduced, so that contaminants were infiltrated. Similarly, in Comparative Example 4, the penetration of contaminants was observed from the beginning. In Comparative Example 5, the base resin formed micelles and became turbid. For this reason, the appearance of the cured film was also turbid and exhibited poor appearance. In Comparative Example 6, there was a tendency to thicken, and the storage stability was not satisfactory.

Claims (4)

(A) 2-50% by mass of an organic solvent-soluble fluororesin having a radically polymerizable unsaturated bond via a urethane bond,
(B) General formula (1)

(Wherein R ¹ , R ² , R ³ , R ⁴ , R ⁵ and R ⁶ are each a hydrogen atom or a hydrocarbon group having 1 to 10 carbon atoms, and they may be the same or different. Well, n is an integer greater than or equal to 2.)
One-end radical polymerizable polysiloxane represented by the general formula (2)

Wherein R ⁷ , R ⁸ , R ⁹ , R ¹⁰ , R ¹¹ and R ¹² are each a hydrogen atom or a hydrocarbon group having 1 to 10 carbon atoms, and they may be the same or different. Well, p is an integer of 0 to 10, and q is an integer of 2 or more.)
5 to 40% by mass of one-end radical polymerizable polysiloxane represented by
(C) a radically polymerizable monomer having a hydroxyl group of 5 to 50% by mass, and (D) a monomer having a functional group that undergoes radical polymerization with the above components (A) to (C) but does not cause other reactions. Body 0-70 mass%
A coating composition comprising: a base resin (a) comprising a copolymer of: and a curing agent (b) capable of undergoing a crosslinking reaction with the base resin (a).   An organic solvent-soluble fluororesin (A) having a radically polymerizable unsaturated bond via a urethane bond is composed of a fluororesin (A-1) having a hydroxyl group and a radically polymerizable monomer (A-2) having an isocyanate group. The coating composition according to claim 1, which is a reaction product of   The coating composition according to claim 1 or 2, wherein the curing agent (b) capable of undergoing a crosslinking reaction with the base resin (a) is a melamine resin. An article having a cured coating obtained by coating with the coating composition according to any one of claims 1 to 3 and curing the composition.