JP2012246351A - Coating composition and coated article - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a coating composition enabling the heating temperature to be decreased and the heating time to be shortened in a coating step, and providing a coated film having a hardness, even by active energy ray irradiation in an oxygen atmosphere, equal to that of a film obtained by active energy-ray irradiation in a nitrogen atmosphere, and having excellent scratch resistance and weather resistance.SOLUTION: The coating composition includes (A) isosorbide di(meth)acrylate, (B) a hydroxy group-containing resin, and (C) an isocyanate group-containing compound. The isocyanate group-containing compound (C) is obtained by reacting a caprolactone-modified hydroxyalkyl (meth)acrylate with a polyisocyanate compound, and preferably contains (C-1) a radically polymerizable unsaturated group-containing compound having an isocyanate equivalent within the range of 300-3,800.

Description

  The present invention relates to a coating composition and a coated article.

  A clear coating film is formed after an electrodeposition coating film, an intermediate coating film, and a base coating film are formed on a vehicle body or a part of a vehicle such as a motorcycle, an automobile, or a container as necessary. Clear coatings generally contain a thermosetting coating composition containing a thermosetting functional group-containing resin such as a hydroxyl group-containing acrylic resin and a crosslinking agent such as a melamine resin, an acid group-containing resin, and an epoxy group-containing resin. It is formed by a coating film forming method in which a thermosetting coating composition or the like is applied and then heated and cured. According to this coating film forming method, a coating film excellent in coating film performance such as adhesion and coating film hardness can be formed.

  In recent years, energy saving and productivity improvement are required in the painting process. Accordingly, coating compositions that can be cured at a low temperature and coating compositions that can be cured in a short time are expected. However, the thermosetting coating composition usually requires a heating temperature of about 140 ° C. and a heating time of about 20 to 40 minutes in a general coating process, and energy saving and productivity improvement are required. It was.

  As an invention for shortening the heating time, Patent Document 1 discloses UV curable and thermosetting containing an ultraviolet curable polyfunctional (meth) acrylate, a polyhydric alcohol mono (meth) acrylate polymer, and a polyisocyanate compound. An invention of a coating composition is disclosed. Further, an invention is disclosed in which a coating film is formed by applying this coating composition to an object to be coated, then irradiating with ultraviolet rays, and then heating and curing for about 30 minutes. However, this invention cannot shorten the heating time and is not satisfactory in terms of scratch resistance.

  Patent Document 2 discloses a urethane (meth) acrylate containing a (meth) acryloyl group and a free isocyanate group, optionally a polyisocyanate other than the urethane (meth) acrylate, an ultraviolet initiator that initiates free radical polymerization, and an isocyanate. An invention of a coating composition containing a compound containing a reactive group is disclosed. Also disclosed is an invention of a method for forming a coating film, characterized in that the coating composition is applied to a support, polymerized by ultraviolet irradiation, and then cured by a reaction between an NCO group and an isocyanate-reactive group. . The present invention can rapidly cure ultraviolet rays and can provide sufficient curing even in non-irradiated areas and poorly irradiated areas. However, this invention is not satisfactory in terms of scratch resistance and weather resistance.

  Furthermore, in Patent Document 3, a base coating composition is applied on an object to be coated to form a base coating film, and then a clear coating composition is applied in a wet-on-wet process to form a clear coating film. A multilayer coating film forming method is disclosed in which an active energy ray is irradiated to a clear coating film before baking or curing. The clear coating composition in this method of forming a multi-layer coating film contains a thermally curable component and a component containing a radical polymerizable double bond, and the thermally curable component is substantially free of radical polymerizable double components. It is characterized by not including bonds. This invention has an advantage that the clear coating composition has a simple composition and can be blended from known components, but the heating temperature cannot be lowered, and it is not satisfactory in terms of scratch resistance.

  Moreover, the composition by the component hardened | cured with the conventional active energy ray normally had the hardening inhibition by oxygen, when active energy ray irradiation was performed in oxygen atmosphere. Therefore, compared with the case where active energy ray irradiation is performed in a nitrogen atmosphere, there is a problem that the curability, particularly the hardness of the cured coating film, is lowered.

JP-A-63-113085 JP 11-263939 A JP-T-2001-524868

  The present invention has been made in view of the above circumstances, and it is an object of the present invention to reduce the heating temperature and shorten the heating time in the coating process, and also to irradiate active energy rays in an oxygen atmosphere in a nitrogen atmosphere. It is an object of the present invention to provide a coating composition in which a cured coating film having the same hardness as that of irradiation with active energy rays below can be obtained, and the cured coating film is excellent in scratch resistance and weather resistance.

  As a result of intensive studies in order to solve the above-mentioned problems, the present inventors have found a problem by using a coating composition containing a specific radical polymerizable unsaturated group-containing compound, a hydroxyl group-containing resin, and an isocyanate group-containing compound. As a result, the present invention has been completed.

That is, the present invention
1. A coating composition comprising isosorbide di (meth) acrylate (A), a hydroxyl group-containing resin (B) and an isocyanate group-containing compound (C),
2. The coating composition according to 1, wherein the hydroxyl group-containing resin (B) is a hydroxyl group-containing acrylic resin,
3. The coating composition according to 1 or 2, wherein the glass transition temperature of the hydroxyl group-containing resin (B) is 0 ° C or higher,
4). The isocyanate group-containing compound (C) is obtained by reacting a caprolactone-modified hydroxyalkyl (meth) acrylate with a polyisocyanate compound, and contains a radical polymerizable unsaturated group having an isocyanate equivalent weight in the range of 300 to 3,800. The coating composition according to any one of 1 to 3, comprising the compound (C-1),
5. 5. The isocyanate group-containing compound (C) according to any one of 1 to 4, further comprising an isocyanate compound (C-2) other than the compound (C-1) in addition to the compound (C-1). Coating composition of the
6). Furthermore, the coating composition of any one of 1 thru | or 5 containing a photoinitiator (D),
7). Furthermore, the coating composition of any one of 1 thru | or 6 containing radically polymerizable unsaturated group containing compounds (E) other than the said isosorbide di (meth) acrylate (A) and a compound (C-1),
8). The coating composition according to any one of 1 to 7, further comprising a color pigment,
A coated article obtained by applying the coating composition according to any one of 9.1 to 8,
About.

  According to the present invention, the heating temperature in the coating process can be lowered and the heating time can be shortened, and the active energy ray irradiation in an oxygen atmosphere has the same hardness as that of the active energy ray irradiation in a nitrogen atmosphere. A cured coating film can be obtained, and further, a coating composition in which the cured coating film is excellent in scratch resistance and weather resistance can be obtained.

Coating Composition The coating composition of the present invention contains isosorbide di (meth) acrylate (A), a hydroxyl group-containing resin (B), and an isocyanate group-containing compound (C).

Isosorbide di (meth) acrylate (A)
Isosorbide di (meth) acrylate (A) used in the present invention [hereinafter sometimes simply referred to as “compound (A)”. ] Is usually the following general formula

(In the above formula, R ¹ represents a hydrogen atom or a (meth) acryloyl group.) Although not particularly limited, it is produced from isosorbide using the following (meth) acrylated reaction. Can do. Isosorbide can be produced by a known production method. That is, it can be produced by dehydrating sorbitol by the action of various dehydration catalysts, particularly strong acid catalysts. Examples of the catalyst include sulfuric acid, paratoluenesulfonic acid, methanesulfonic acid, hydrochloric acid, phosphoric acid and the like. These dehydration reactions are generally performed efficiently in water and other organic solvents such as toluene and xylene. As the (meth) acrylate reaction, a method of esterifying a hydroxyl group using (meth) acrylic acid halide or (meth) acrylic anhydride, or an ester of a lower alcohol of (meth) acrylic acid such as MMA is used. Transesterification, DCC (N, N'-dicyclohexylcarbodiimide), WSCD (water-soluble carbodiimide) and other carbodiimide-based dehydration condensing agents using (meth) acrylic acid dehydration condensation method, or using acid catalyst For example, a dehydrating condensation method. If necessary, a known polymerization inhibitor may be used so that polymerization does not proceed during production or during product storage.

Hydroxyl-containing resin (B)
The hydroxyl group-containing resin (B) is a resin having at least one hydroxyl group in one molecule. Examples of the hydroxyl group-containing resin (B) include resins having a hydroxyl group, such as polyester resins, acrylic resins, polyether resins, polycarbonate resins, polyurethane resins, epoxy resins, and alkyd resins. These can be used alone or in combination of two or more. Especially, it is preferable that a hydroxyl-containing resin (B) is a hydroxyl-containing acrylic resin from the point of the weather resistance of the coating film obtained.

  The hydroxyl group-containing acrylic resin is usually prepared by a hydroxyl group-containing polymerizable unsaturated monomer and other polymerizable unsaturated monomers copolymerizable with the hydroxyl group-containing polymerizable unsaturated monomer in a manner known per se, for example, in an organic solvent. It can manufacture by making it copolymerize by methods, such as the solution polymerization method of this, and the emulsion polymerization method in water.

  The hydroxyl group-containing polymerizable unsaturated monomer is a compound having at least one hydroxyl group and one polymerizable unsaturated bond in one molecule. Specifically, for example, 2-hydroxyethyl (meth) acrylate, 2-hydroxy Monoesterified product of (meth) acrylic acid such as propyl (meth) acrylate, 3-hydroxypropyl (meth) acrylate and 4-hydroxybutyl (meth) acrylate and a dihydric alcohol having 2 to 8 carbon atoms; Ε-caprolactone modified product of monoesterified product of acrylic acid and dihydric alcohol having 2 to 8 carbon atoms; N-hydroxymethyl (meth) acrylamide; allyl alcohol, and further, polyoxyethylene chain whose molecular terminal is a hydroxyl group A (meth) acrylate etc. can be mentioned.

  Examples of the other polymerizable unsaturated monomer copolymerizable with the hydroxyl group-containing polymerizable unsaturated monomer include 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, n-octyl (meth) acrylate, 2-ethylhexyl (meth) Acrylate, nonyl (meth) acrylate, tridecyl (meth) acrylate, lauryl (meth) acrylate, stearyl (meth) acrylate, “isostearyl acrylate” (trade name, manufactured by Osaka Organic Chemical Industry Co., Ltd.), cyclohexyl (meth) acrylate, methyl Cyclohexyl Alkyl or cycloalkyl (meth) acrylate such as (meth) acrylate, t-butylcyclohexyl (meth) acrylate, cyclododecyl (meth) acrylate; polymerizable unsaturated monomer having an isobornyl group such as isobornyl (meth) acrylate; adamantyl ( Polymerizable unsaturated monomers having an adamantyl group such as (meth) acrylate; vinyl aromatic compounds such as styrene, α-methylstyrene and vinyltoluene; vinyltrimethoxysilane, vinyltriethoxysilane, vinyltris (2-methoxyethoxy) silane, polymerizable unsaturated monomers having alkoxysilyl groups such as γ- (meth) acryloyloxypropyltrimethoxysilane, γ- (meth) acryloyloxypropyltriethoxysilane; Perfluoroalkyl (meth) acrylates such as (meth) acrylate and perfluorooctylethyl (meth) acrylate; polymerizable unsaturated monomers having a fluorinated alkyl group such as fluoroolefin; and having a photopolymerizable functional group such as a maleimide group Polymerizable unsaturated monomers; vinyl compounds such as N-vinylpyrrolidone, ethylene, butadiene, chloroprene, vinyl propionate and vinyl acetate; carboxyl groups such as (meth) acrylic acid, maleic acid, crotonic acid and β-carboxyethyl acrylate Polymerizable unsaturated monomer: (meth) acrylonitrile, (meth) acrylamide, N, N-dimethylaminoethyl (meth) acrylate, N, N-dimethylaminopropyl (meth) acrylamide, amine compound with glycidyl (meth) acrylate Containing nitrogen-containing polymerizable unsaturated monomers such as adducts; and polymerizable unsaturated groups having at least two polymerizable unsaturated groups such as allyl (meth) acrylate and 1,6-hexanediol di (meth) acrylate in one molecule. Saturated monomer: glycidyl (meth) acrylate, β-methylglycidyl (meth) acrylate, 3,4-epoxycyclohexylmethyl (meth) acrylate, 3,4-epoxycyclohexylethyl (meth) acrylate, 3,4-epoxycyclohexylpropyl ( Epoxy group-containing polymerizable unsaturated monomers such as meth) acrylate and allyl glycidyl ether; (meth) acrylate having a polyoxyethylene chain whose molecular terminal is an alkoxy group; 2-acrylamido-2-methylpropanesulfonic acid, allylsulfonic acid , Sodium styrene sulfonate Polymerizable unsaturated monomers having a sulfonic acid group such as um salt, sulfoethyl methacrylate and its sodium salt, ammonium salt; 2-acryloyloxyethyl acid phosphate, 2-methacryloyloxyethyl acid phosphate, 2-acryloyloxypropyl acid phosphate, Polymerizable unsaturated monomers having a phosphate group such as 2-methacryloyloxypropyl acid phosphate; 2-hydroxy-4- (3-methacryloyloxy-2-hydroxypropoxy) benzophenone, 2-hydroxy-4- (3-acryloyloxy) 2-hydroxypropoxy) benzophenone, 2,2'-dihydroxy-4- (3-methacryloyloxy-2-hydroxypropoxy) benzophenone, 2,2'-dihydroxy-4- Polymerizable unsaturated monomers having an ultraviolet-absorbing functional group such as (3-acryloyloxy-2-hydroxypropoxy) benzophenone, 2- (2′-hydroxy-5′-methacryloyloxyethylphenyl) -2H-benzotriazole; 4 -(Meth) acryloyloxy-1,2,2,6,6-pentamethylpiperidine, 4- (meth) acryloyloxy-2,2,6,6-tetramethylpiperidine, 4-cyano-4- (meth) Acryloylamino-2,2,6,6-tetramethylpiperidine, 1- (meth) acryloyl-4- (meth) acryloylamino-2,2,6,6-tetramethylpiperidine, 1- (meth) acryloyl-4 -Cyano-4- (meth) acryloylamino-2,2,6,6-tetramethylpiperidine, 4-crotonoyl Oxy-2,2,6,6-tetramethylpiperidine, 4-crotonoylamino-2,2,6,6-tetramethylpiperidine, 1-crotonoyl-4-crotonoyloxy-2,2,6,6- UV-stable polymerizable unsaturated monomers such as tetramethylpiperidine; acrolein, diacetone acrylamide, diacetone methacrylamide, acetoacetoxyethyl methacrylate, formylstyrol, vinyl alkyl ketones having 4 to 7 carbon atoms (eg, vinylmethyl Examples thereof include polymerizable unsaturated monomer compounds having a carbonyl group such as ketone, vinyl ethyl ketone, and vinyl butyl ketone, and these can be used alone or in combination of two or more.

  The hydroxyl group-containing resin (B) is generally 30 to 300 mgKOH / g, particularly 40 to 250 mgKOH / g, more particularly 50 to 200 mgKOH / g, from the viewpoint of curability at low temperature and the water resistance of the resulting coating film. It preferably has a hydroxyl value within the range.

  The hydroxyl group-containing resin (B) preferably has an acid group such as a carboxyl group from the viewpoint of increasing the reactivity with the compound (A).

  The hydroxyl group-containing resin (B) preferably has an acid value within the range of 1 to 25 mgKOH / g, particularly 1 to 20 mgKOH / g.

  The hydroxyl group-containing resin (B) generally has a weight average molecular weight in the range of 3,000 to 100,000, particularly 4,000 to 50,000, more preferably 5,000 to 30,000.

  The hydroxyl group-containing resin (B) preferably has a glass transition temperature of 0 ° C. or higher, particularly 5 ° C. to 50 ° C. from the viewpoint of scratch resistance and weather resistance.

  Here, the glass transition temperature (° C.) is a static glass transition temperature. For example, using a differential scanning calorimeter “DSC-50Q type” (manufactured by Shimadzu Corporation, trade name), a sample is taken into a measuring cup and vacuum suctioned. After removing the solvent completely, the change in calorie is measured in the range of -100 ° C to 100 ° C at a rate of temperature increase of 3 ° C / min, and the first base point change point on the low temperature side is taken as the glass transition temperature. be able to.

Isocyanate group-containing compound (C)
The isocyanate group-containing compound (C) is a compound having at least one isocyanate group in one molecule. In the present invention, radical polymerizability obtained by reacting caprolactone-modified hydroxyalkyl (meth) acrylate and a polyisocyanate compound as the isocyanate group-containing compound (C) and having an isocyanate equivalent weight in the range of 300 to 3,800. Unsaturated group-containing compound (C-1) [Hereinafter, sometimes simply referred to as “compound (C-1).” It is preferable from the viewpoint of improving the scratch resistance and weather resistance of the resulting coating film.

Compound (C-1)
Compound (C-1) is obtained by reacting caprolactone-modified hydroxyalkyl (meth) acrylate and a polyisocyanate compound, and has an isocyanate equivalent weight in the range of 300 to 3,800. This compound (C-1) is excellent in curability by irradiation with active energy rays, and further excellent in curability at a low temperature (specifically, normal temperature to 100 ° C.). This makes it possible to lower the heating temperature and shorten the heating time in the coating process. Moreover, this compound (C-1) contributes to the improvement of the scratch resistance and weather resistance of the coating film obtained.

  The caprolactone-modified hydroxyalkyl (meth) acrylate is a compound represented by the following general formula (I).

[Wherein, R ¹ represents a hydrogen atom or a methyl group, R ² represents an alkylene group having 2 to 6 carbon atoms, and n is 1 to 5. ].

Specifically, the caprolactone-modified hydroxyalkyl (meth) acrylate includes “Placcel FA-1”, “Placcel FA-2”, “Placcel FA-2D”, “Placcel FA-3”, “Placcel FA-4”, “Placcel FA-5”, “Plaxel FM-1”, “Plaxel FM-2”, “Plaxel FM-2D”, “Plaxel FM-3”, “Plaxel FM-4”, “Plaxel FM-5” (any Can also be mentioned by Daicel Chemical Industries, trade name). Among them, from the viewpoint of active energy ray curability, in general formula (I), R ¹ is a hydrogen atom, R ² is an ethylene group, and n is in the range of 1 to 3, particularly n is 2. Modified hydroxyethyl acrylate is preferred.

  The polyisocyanate compound is a compound having two or more isocyanate groups in one molecule. For example, aliphatic polyisocyanate compounds such as hexamethylene diisocyanate, trimethylhexamethylene diisocyanate, dimer acid diisocyanate, lysine diisocyanate, and burette-type adducts, isocyanurate cycloadducts of these polyisocyanates; isophorone diisocyanate, 4,4′- Methylenebis (cyclohexyl isocyanate), methylcyclohexane-2,4-diisocyanate, methylcyclohexane-2,6-diisocyanate, 1,3-di (isocyanatomethyl) cyclohexane, 1,4-di (isocyanatomethyl) cyclohexane, 1, Alicyclic diisocyanates such as 4-cyclohexane diisocyanate, 1,3-cyclopentane diisocyanate, 1,2-cyclohexane diisocyanate Compounds and burette type adducts, isocyanurate cycloadducts of these polyisocyanates; xylylene diisocyanate, metaxylylene diisocyanate, tetramethyl xylylene diisocyanate, tolylene diisocyanate, 4,4'-diphenylmethane diisocyanate, 1,5 -Naphthalene diisocyanate, 1,4-naphthalene diisocyanate, 4,4'-toluidine diisocyanate, 4,4'-diphenyl ether diisocyanate, m-phenylene diisocyanate, p-phenylene diisocyanate, 4,4'-biphenylene diisocyanate, 3,3'- Dimethyl-4,4′-biphenylene diisocyanate, bis (4-isocyanatophenyl) sulfone, isopropylidenebis (4-phenylisocyanate) G) aromatic diisocyanate compounds such as these and burette type adducts, isocyanurate cycloadducts of these polyisocyanates; triphenylmethane-4,4 ′, 4 ″ -triisocyanate, 1,3,5-triisocyanate Polyisocyanate having three or more isocyanate groups in one molecule such as natobenzene, 2,4,6-triisocyanatotoluene, 4,4′-dimethyldiphenylmethane-2,2 ′, 5,5′-tetraisocyanate Compounds and burette type adducts and isocyanurate cycloadducts of these polyisocyanates; polyols such as ethylene glycol, propylene glycol, 1,4-butylene glycol, dimethylolpropionic acid, polyalkylene glycol, trimethylolpropane, hexanetriol Of hydroxy acid Urethane adduct isocyanate groups obtained by reacting a polyisocyanate compound in a ratio comprising an excess and biuret type adducts of these polyisocyanates, isocyanurate ring adducts, and the like in. These can be used as one or a mixture of two or more. Among these, from the viewpoint of the weather resistance of the coating film, an isocyanurate cycloadduct of an aliphatic polyisocyanate compound is preferable, and an isocyanurate cycloadduct of hexamethylene diisocyanate is particularly preferable.

  The reaction of the caprolactone-modified hydroxyalkyl (meth) acrylate and the polyisocyanate compound can be performed by a known method for reacting the hydroxy group-containing compound with the polyisocyanate compound.

  The above reaction can usually be carried out in an organic solution. Examples of organic solvents include aromatic hydrocarbon solvents such as toluene and xylene, ketone solvents such as acetone, methyl ethyl ketone, methyl isobutyl ketone, and cyclohexanone, and ester solvents such as ethyl acetate, propyl acetate, isobutyl acetate, and butyl acetate. Can be mentioned. These can be used as one or a mixture of two or more.

  The reaction temperature is preferably from room temperature to 100 ° C., and the reaction time is preferably from 1 to 10 hours.

  In the above reaction, a catalyst such as dibutyltin dilaurate, dibutyltin diethylhexoate or dibutyltin sulfite may be used as necessary. The addition amount of the catalyst is preferably 0.01 to 1 part by mass and more preferably 0.1 to 0.5 part by mass with respect to 100 parts by mass of the total amount of reaction raw materials. A polymerization inhibitor such as hydroquinone monomethyl ether may be used. It is preferable that the addition amount of a polymerization inhibitor is 0.01-1 mass part with respect to 100 mass parts of total amounts of a reaction raw material.

  Since compound (C-1) has an isocyanate group, the mixing ratio in the reaction of caprolactone-modified hydroxyalkyl (meth) acrylate and polyisocyanate compound is usually such that the isocyanate group of the polyisocyanate compound is caprolactone-modified hydroxyalkyl (meta ) The mixing ratio is excessive (isocyanate group / hydroxyl group> 1.0) in an equivalent ratio with respect to the hydroxyl group of the acrylate. And the isocyanate equivalent of a compound (C-1) can be adjusted by adjusting a mixing ratio.

  Compound (C-1) has an isocyanate equivalent weight in the range of 300 to 3,800. The compound (C-1) preferably has an isocyanate equivalent weight in the range of 500 to 2,500 from the viewpoint of scratch resistance of the coating film. When the compound (C-1) has an isocyanate group, the coating composition of the present invention is excellent in curability at low temperatures. Moreover, when a compound (C-1) has an isocyanate group, a compound (C-1) reacts with a hydroxyl-containing resin (B), and forms a tough coating film.

  Moreover, when using a compound (C-1) for a multilayer coating film, the isocyanate equivalent of a compound (C-1) is 300-3,800, Furthermore, the range of 500-2500 is preferable. By setting the isocyanate equivalent within the above range, a multilayer coating film excellent in scratch resistance can be obtained, and the compound (C-1) is difficult to penetrate into the base coating film, and both the adhesion and finish properties are good. A layer coating can be obtained. In particular, when the base coating composition is a coating composition containing a bright pigment, the compound (C-1) is less likely to penetrate into the base coating, thereby preventing the orientation of the bright pigment in the base coating from being disturbed, The finish of the resulting multilayer coating film is good.

  Here, in this specification, an isocyanate equivalent means the molar mass per isocyanate group. When the g molecular weight of the compound is M and the number of isocyanate groups contained in one molecule of the compound is ν, the isocyanate equivalent is represented by M / ν.

  Moreover, in this specification, an isocyanate equivalent is an isocyanate equivalent calculated | required by back titration using a dibutylamine. The reverse titration is carried out by adding excess dibutylamine to the sample for reaction, and titrating the remaining dibutylamine with an aqueous hydrochloric acid solution using bromophenol blue as a titration indicator.

  The compound (C-1) preferably has an unsaturated group equivalent of 300 to 2,000, more preferably 500 to 1,000. When the unsaturated group equivalent is within this range, it is possible to obtain a coating film having more excellent scratch resistance and weather resistance.

  Here, in this specification, an unsaturated group equivalent means the molar mass per unsaturated group by adding excess dodecyl mercaptan to a compound (C-1). When the g molecular weight of the compound is M and the number of unsaturated groups contained in one molecule of the compound is σ, the unsaturated group equivalent is expressed by M / σ.

  Further, in this specification, the unsaturated group equivalent is determined by adding dodecyl mercaptan to a radical polymerizable unsaturated group and back titrating the remaining dodecyl mercaptan with an iodine solution.

  The molecular weight of the compound (C-1) is not particularly limited, and the weight average molecular weight is preferably 500 to 2,000, more preferably 800 to 1,500. It is significant that the weight average molecular weight is within these ranges in that the viscosity of the paint can be easily handled.

Here, in this specification, the weight average molecular weight uses tetrahydrofuran as a solvent, and the retention time (retention capacity) measured with a gel permeation chromatograph (“HLC8120GPC” manufactured by Tosoh Corporation) is the weight average of polystyrene. It is a value converted based on the molecular weight. The columns are 4 pieces of “TSKgel G-4000H _XL ”, “TSKgel G-3000H _XL ”, “TSKgel G-2500H _XL ”, “TSKgel G-2000 _XL ” (both manufactured by Tosoh Corporation, trade name). , Mobile phase: tetrahydrofuran, measurement temperature: 40 ° C., flow rate: 1 ml / min, detector: under the conditions of RI.

Isocyanate compound (C-2)
In the present invention, the isocyanate group-containing compound (C) can contain an isocyanate compound (C-2) other than the compound (C-1).

  The isocyanate compound (C-2) is a compound having two or more isocyanate groups in the molecule, and examples thereof include the polyisocyanate compounds exemplified in the description of the compound (C-1). Among these, from the viewpoint of the weather resistance of the resulting coating film, an isocyanurate cycloadduct of an aliphatic polyisocyanate compound is preferable, and an isocyanurate cycloadduct of hexamethylene diisocyanate is particularly preferable.

Photopolymerization initiator (D)
The coating composition of the present invention can further contain a photopolymerization initiator (D).

  Any photopolymerization initiator can be used without particular limitation as long as it is an initiator that absorbs active energy rays and generates radicals.

  Examples of the photopolymerization initiator include α-diketone compounds such as benzyl and diacetyl; acyloin compounds such as benzoin; acyloin ether compounds such as benzoin methyl ether, benzoin ethyl ether and benzoin isopropyl ether; thioxanthone and 2,4-diethyl Thioxanthone compounds such as thioxanthone, 2-isopropylthioxanthone, thioxanthone-4-sulfonic acid; benzophenone compounds such as benzophenone, 4,4′-bis (dimethylamino) benzophenone, 4,4′-bis (diethylamino) benzophenone; Michler's ketone compound; Acetophenone, 2- (4-toluenesulfonyloxy) -2-phenylacetophenone, p-dimethylaminoacetophenone, α, α'-dimethoxyacetoxybenzophene 2,2'-dimethoxy-2-phenylacetophenone, p-methoxyacetophenone, 2-methyl [4- (methylthio) phenyl] -2-morpholino-1-propanone, 2-benzyl-2-dimethylamino-1- Acetophenone compounds such as (4-morpholinophenyl) -butan-1-one, α-isohydroxyisobutylphenone, α, α'-dichloro-4-phenoxyacetophenone, 1-hydroxy-cyclohexyl-phenyl-ketone; 2,4 Acylphosphine oxide compounds such as 1,6-trimethylbenzoyldiphenylphosphine oxide and bis (acyl) phosphine oxide; quinones such as anthraquinone and 1,4-naphthoquinone; phenacyl chloride, trihalomethylphenylsulfone, tris (trihalomethy) ) -S-halogen compounds such as triazine; peroxides such as di -t- butyl peroxide and the like. These can be used as one or a mixture of two or more.

  Examples of commercially available photopolymerization initiators include IRGACURE-184, IRGACURE-261, IRGACURE-500, IRGACURE-651, IRGACURE-907, IRGACURE-CGI-1700 (trade name, manufactured by Ciba Specialty Chemicals). Darocur-1173, Darocur-1116, Darocur-2959, Darocur-1664, Darocur-4043 (trade name, manufactured by Merck Japan), Kayacure-MBP, Kayacure-DETX-S, Kayacure-DMBI, Kayacure-EPA, Kayacure-OA (trade name, manufactured by Nippon Kayaku Co., Ltd.), VICURE-10, Vicure-55 (trade name, manufactured by STAUFFER Co., LTD.), Trigonal P1 [AKZO Co., LTD. Made , Product name], SANDORAY 1000 (manufactured by SANDOZ Co., LTD., Product name), Deep (DEAP) (manufactured by APJOHN Co., LTD., Product name), CANTACURE ( QUANTACURE) -PDO, CANTACURE-ITX, CANTACURE-EPD (trade name, manufactured by WARD BLEKINSOP Co., LTD.), And the like.

Radical polymerizable unsaturated group-containing compound (E)
The coating composition of the present invention can further contain a radically polymerizable unsaturated group-containing compound (E) other than the compounds (A) and (C-1).

  Examples of the radically polymerizable unsaturated group-containing compound (E) include monofunctional radically polymerizable unsaturated group-containing compounds and polyfunctional radically polymerizable unsaturated group-containing compounds.

  Examples of the monofunctional radical polymerizable unsaturated group-containing compound include esterified products of monohydric alcohol and (meth) acrylic acid. Specifically, for example, methyl (meth) acrylate, ethyl (meth) acrylate, n-propyl (meth) acrylate, isopropyl (meth) acrylate, n-butyl (meth) acrylate, isobutyl (meth) acrylate, t-butyl (Meth) acrylate, neopentyl (meth) acrylate, cyclohexyl (meth) acrylate, tetrahydrofurfuryl (meth) acrylate, isobornyl (meth) acrylate, phenyl (meth) acrylate, benzyl (meth) acrylate, N-acryloyloxyethylhexahydro Examples include phthalimide.

  Also, for example, hydroxyl-containing (meth) acrylates such as hydroxyethyl (meth) acrylate, hydroxypropyl (meth) acrylate, hydroxybutyl (meth) acrylate; acrylic acid, methacrylic acid, crotonic acid, itaconic acid, maleic acid, fumaric acid Carboxyl group-containing (meth) acrylates such as 2-carboxyethyl (meth) acrylate, 2-carboxypropyl (meth) acrylate and 5-carboxypentyl (meth) acrylate; glycidyl groups such as glycidyl (meth) acrylate and allyl glycidyl ether -Containing radically polymerizable unsaturated group-containing compounds; vinyl aromatic compounds such as styrene, α-methylstyrene, vinyltoluene, α-chlorostyrene; N, N-dimethylaminoethyl (meth) acrylate, N, N-die Nitrogen-containing alkyl (meth) acrylates such as tilaminoethyl (meth) acrylate and Nt-butylaminoethyl (meth) acrylate; acrylamide, methacrylamide, N-methyl (meth) acrylamide, N-ethyl (meth) acrylamide, N-methylol (meth) acrylamide, N-methoxymethyl (meth) acrylamide, N-butoxymethyl (meth) acrylamide, N, N-dimethyl (meth) acrylamide, N, N-dimethylaminopropyl (meth) acrylamide, N, Examples thereof include polymerizable amide compounds such as N-dimethylaminoethyl (meth) acrylamide.

  Examples of the polyfunctional radical polymerizable unsaturated group-containing compound include esterified products of polyhydric alcohol and (meth) acrylic acid. Specifically, for example, ethylene glycol di (meth) acrylate, diethylene glycol di (meth) acrylate, triethylene glycol di (meth) acrylate, tetraethylene glycol di (meth) acrylate, 1,3-butanediol di (meth) Acrylate, 1,4-butanediol di (meth) acrylate, 1,9-nonanediol di (meth) acrylate, glycerin di (meth) acrylate, trimethylolpropane di (meth) acrylate, pentaerythritol di (meth) acrylate, Dipentyl glycol di (meth) acrylate, 1,6-hexanediol di (meth) acrylate, pentaerythritol di (meth) acrylate, bisphenol A ethylene oxide modified di (meth) acrylate, etc. Meth) acrylate compounds; glycerin tri (meth) acrylate, trimethylolpropane tri (meth) acrylate, trimethylolpropane propylene oxide modified tri (meth) acrylate, trimethylolpropane ethylene oxide modified tri (meth) acrylate, pentaerythritol tri (meth) ) Acrylate, ε-caprolactone modified tris (acryloxyethyl) isocyanurate, etc. tri (meth) acrylate compound; pentaerythritol tetra (meth) acrylate etc. tetra (meth) acrylate compound; other dipentaerythritol penta (meth) acrylate And dipentaerythritol hexa (meth) acrylate. Furthermore, urethane (meth) acrylate resin, epoxy (meth) acrylate resin, polyester (meth) acrylate resin and the like can be mentioned. The urethane (meth) acrylate resin is obtained, for example, by using a polyisocyanate compound, a hydroxylalkyl (meth) acrylate, and a polyol compound as raw materials and reacting them in an amount such that the hydroxyl group is equimolar or excessive with respect to the isocyanate group. be able to. These radically polymerizable unsaturated group-containing compounds can be used alone or in combination of two or more.

  The radical-polymerizable unsaturated group-containing compound (E) preferably contains a tri- or higher functional radical-polymerizable unsaturated group-containing compound from the viewpoint of scratch resistance of the coating film.

  The radically polymerizable unsaturated group-containing compound (E) preferably contains a radically polymerizable unsaturated group-containing compound having a hydroxyl group from the viewpoint of low temperature curability.

  The radical polymerizable unsaturated group-containing compound (E) preferably has an unsaturated group equivalent of 100 to 1,500, more preferably 150 to 1, from the viewpoint of low-temperature curability and scratch resistance of the coating film. 000.

  As the radically polymerizable unsaturated group-containing compound (E), an aliphatic urethane acrylate compound is preferably used from the viewpoint of scratch resistance and weather resistance.

  The content of each of the above components in the coating composition of the present invention is not particularly limited, but the following range is preferable from the viewpoint of the following coating film performance.

  The content of the compound (A) is preferably 1 to 80 parts by mass, more preferably 20 to 70 parts by mass with respect to 100 parts by mass of the nonvolatile content of the coating composition of the present invention. These ranges are significant in terms of scratch resistance, acid resistance, and finish (moisture resistance) when a multilayer film is formed by wet-on-wet.

  The content of the hydroxyl group-containing resin (B) is preferably 1 to 70 parts by mass, more preferably 10 to 60 parts by mass with respect to 100 parts by mass of the nonvolatile content of the coating composition of the present invention. These ranges are significant in terms of low-temperature curability.

  The mixing ratio of the hydroxyl group-containing resin (B) and the isocyanate group-containing compound (C) is such that the total amount of isocyanate groups of the isocyanate group-containing compound (C) and the hydroxyl groups of the hydroxyl group-containing resin (B) are equivalent ratios. The range in which NCO / OH = 0.30 to 2.00 is preferable, and the range in which 0.50 to 1.80 is satisfied is more preferable. These ranges are significant in terms of scratch resistance and weather resistance of the coating film.

  The content of the compound (C-1) is preferably 1 to 70 parts by mass, more preferably 10 to 40 parts by mass with respect to 100 parts by mass of the nonvolatile content of the coating composition of the present invention. These ranges are significant in terms of scratch resistance and weather resistance.

  The content of the isocyanate compound (C-2) is preferably 5 to 30 parts by mass, more preferably 10 to 25 parts by mass with respect to 100 parts by mass of the nonvolatile content of the coating composition of the present invention. These ranges are significant in terms of low-temperature curability.

  When the compound (C-1) and the isocyanate compound (C-2) are used in combination, the compounding ratio of the compound (C-1) and the isocyanate compound (C-2) is the isocyanate group of the compound (C-1). And the isocyanate group of the isocyanate compound (C-2) are preferably in a range where the NCO of the compound (C-1) / NCO of the isocyanate compound (C-2) is 0.10 to 9.00 in an equivalent ratio, A range of 0.20 to 4.00 is more preferable. These ranges are significant in terms of acid resistance of the coating film.

  Moreover, when using a photoinitiator (D), the content becomes like this. Preferably, it is 1-8 mass parts with respect to 100 mass parts of non volatile matters of the coating composition of this invention, More preferably, it is 2-6. Part by mass. These ranges are significant in terms of reactivity to active energy rays.

  When the radical polymerizable unsaturated group-containing compound (E) is used, the content thereof is preferably 1 to 50 parts by mass, more preferably 100 parts by mass with respect to the nonvolatile content of the coating composition of the present invention. 5 to 40 parts by mass. These ranges are significant in terms of scratch resistance and weather resistance.

  The coating composition of the present invention further comprises, if necessary, a colorant, an extender pigment, a curing catalyst, a thickener, an ultraviolet absorber, a light stabilizer, an antifoaming agent, a rust inhibitor, a plasticizer, an organic solvent, a surface Ordinary paint additives such as a regulator and an anti-settling agent can be contained alone or in combination of two or more.

  As the colorant, a color pigment or a dye can be used, and examples of the color pigment include aluminum paste, pearl powder, graphite, bright pigments such as MIO, titanium white, phthalocyanine blue, and carbon black. Examples of extender pigments include talc and barium sulfate. When blending a colorant or extender, the content thereof is preferably in the range of 0.01 to 250 parts by mass with respect to 100 parts by mass of the nonvolatile content of the coating composition of the present invention. Moreover, when using the coating composition of this invention as a clear coating, it is desirable to adjust content of the said coloring material and extender to such an extent that transparency is not lost.

  As the ultraviolet absorber, conventionally known ones can be used. For example, a benzotriazole-based absorbent, a triazine-based absorbent, a salicylic acid derivative-based absorbent, a benzophenone-based absorbent, or the like can be used. Examples of the ultraviolet absorber include known polymerizable ultraviolet absorbers such as 2- (2′-hydroxy-5′-methacryloyloxyethylphenyl) -2H-benzotriazole, 2,2′-dihydroxy-4 (3- Methacryloxy-2-hydroxypropoxy) benzophenone and the like can also be used. Examples of commercially available ultraviolet absorbers include TINUVIN 900, TINUVIN 928, TINUVIN 348-2, TINUVIN 479, TINUVIN 405 (trade name, manufactured by Ciba Specialty Chemicals), and RUVA 93 (trade name, manufactured by Otsuka Chemical Co., Ltd.).

  When mix | blending the said ultraviolet absorber, Preferably the inside of the range of 0.1-10 mass parts is suitable with respect to 100 mass parts of non volatile matters of the coating composition of this invention.

  On the other hand, the light stabilizer is used as a radical chain inhibitor that traps active radical species generated during the deterioration process of the film, and includes, for example, a hindered amine light stabilizer.

  Among the light stabilizers, hindered piperidines may be mentioned as light stabilizers that exhibit an excellent light stabilizing action. Also, known polymerizable light stabilizers can be used. Commercially available light stabilizers include, for example, TINUVIN 123, TINUVIN 152, TINUVIN 292 (trade name, manufactured by Ciba Specialty Chemicals), HOSTAVIN 3058 (trade name, manufactured by Clariant), ADK STAB LA-82 (trade name, manufactured by ADEKA Corporation) Etc.

  When the light stabilizer is blended, the content thereof is preferably in the range of 0.1 to 5 parts by mass with respect to 100 parts by mass of the nonvolatile content of the coating composition of the present invention.

  The coating composition of the present invention may be either an organic solvent-type coating composition or a water-based coating composition, but is preferably an organic solvent-type coating composition from the viewpoint of storage stability and the like. In the present specification, the water-based coating composition is a coating in which the main component of the solvent is water, and the organic solvent-type coating composition is a coating that does not substantially contain water as a solvent.

  The organic solvent used in the case of the organic solvent type paint is not particularly limited. Specific examples include ketone solvents such as acetone, methyl ethyl ketone, methyl isobutyl ketone, cyclohexanone, methyl amyl ketone, ethyl isoamyl ketone, diisobutyl ketone, and methyl hexyl ketone; ethyl acetate, butyl acetate, methyl benzoate, methyl propionate Ester solvents such as tetrahydrofuran, dioxane, dimethoxyethane and the like; glycol ether solvents such as propylene glycol monomethyl ether acetate and 3-methoxybutyl acetate; aromatic hydrocarbon solvents, aliphatic hydrocarbon solvents, etc. Is mentioned.

Painted article The present invention provides a coated article obtained by painting the coating composition.

  The article to be coated with the coating composition of the present invention is not particularly limited. For example, metal materials such as iron, aluminum, brass, copper, stainless steel, tinplate, galvanized steel, alloyed zinc (Zn-Al, Zn-Ni, Zn-Fe, etc.) plated steel; polyethylene resin, polypropylene resin, poly Methyl methacrylate resin, acrylonitrile-butadiene-styrene (ABS) resin, polyamide resin, acrylic resin, vinylidene chloride resin, polycarbonate resin, polyurethane resin, epoxy resin and other plastic materials such as FRP; glass, cement, concrete, etc. Inorganic materials; wood; fiber materials (paper, cloth, etc.) and the like, among which metal materials and plastic materials are suitable.

  In addition, the application of the object to be coated with the coating composition of the present invention is not particularly limited, and examples thereof include an outer plate part of an automobile body such as a passenger car, a truck, a motorcycle, and a bus; an automobile part; a mobile phone and an audio. Examples of the outer plate of a household electric product such as a device can be given. Of these, the outer plate of an automobile body and automobile parts are preferable.

  The object to be coated may be obtained by subjecting the metal surface of the metal material or a vehicle body formed from the metal material to a surface treatment such as phosphate treatment, chromate treatment, zirconium treatment, or complex oxide treatment. Good. The object to be coated may be one in which an undercoat film such as various electrodeposition paints is formed on the metal material, the vehicle body or the like. Further, the object to be coated may be one in which a primer coating film is formed on the plastic material.

  Further, the object to be coated may be an uncured or cured film of an aqueous or organic solvent-type primer coating on the plastic material, and further subjected to preheating (preheating) as necessary. Also good.

  Further, the coated object may be one in which a top coat base coat is formed on a primer coat or primer coat on a metal material or plastic material, and a top clear coat is formed on the top coat base coat. It may be what was done. A conventionally well-known coating material can be used as a coating material which forms these undercoat coating film, top coating base coating film, and top coating clear coating film.

Among the above, as the paint for forming the overcoat base film, for example, depending on the film-forming resin such as acrylic resin, polyester resin, epoxy resin, urethane resin, cellulose acetate butyrate, and curable functional groups thereof A film-forming component comprising a curing agent, and the above-described color pigment, aluminum powder, alumina powder, bronze powder, copper powder, tin powder, zinc powder, iron phosphide, metal-coated mica powder, titanium dioxide-coated mica powder, It contains coloring components such as glittering pigments such as titanium dioxide coated glass powder, and as its form, organic solvent type, aqueous type, and other top coat base paints well known by those skilled in the art can be mentioned. . The film thickness of the top coat base paint is preferably 10 to 60 μm as the dry film thickness, and more preferably 15 to 50 μm from the viewpoint of concealability and prevention of wrinkle. Moreover, when the top coat base paint is a water-based type, it is preferable to perform a preheating process with respect to the obtained uncured base coating film. Such a preheating step is, for example, left or dried at a temperature of about room temperature to about 110 ° C. for 3 to 10 minutes.

  The coating composition of the present invention has a nonvolatile content of usually 15% by mass or more, particularly 20 to 35% by mass, and further has a viscosity of 14 to 20 seconds / Ford Cup # 4/20 ° C. It is preferable to adjust within the range.

  The method for applying the coating composition of the present invention is not particularly limited, and for example, it can be applied by air spray, airless spray, rotary atomizer, dip coating, brush or the like. Electrostatic application may be performed during coating. The coating film thickness is usually 10 to 100 μm, preferably 10 to 50 μm, and more preferably 15 to 35 μm as a cured film thickness.

  After coating, preliminary heating (preheating) and air blowing can be performed to reduce the volatile content of the coating film immediately after coating or to remove the volatile content. The preheating can be usually performed by directly or indirectly heating the coated object to be coated in a drying furnace at a temperature of 50 to 110 ° C., preferably 60 to 90 ° C. for 1 to 30 minutes. Moreover, an air blow can be normally performed by spraying the air heated to normal temperature or the temperature of 25 to 80 degreeC on the coating surface of the to-be-coated object.

  When the coating composition of the present invention is cured, heating and active energy ray irradiation are usually performed. The order of heating and active energy ray irradiation is not particularly limited, and active energy ray irradiation may be performed after heating, heating may be performed after active energy ray irradiation, and heating and active energy ray irradiation are performed simultaneously. May be.

  Moreover, when performing heating and active energy ray irradiation simultaneously, it is good also considering the heat | fever (for example, the heat | fever which a lamp | ramp emits) from the irradiation source of an active energy ray as a heat source. Further, when the active energy ray irradiation is performed after the heating, the active energy ray irradiation may be performed in a state where the object to be coated is heated (a state having a residual heat).

  The heating conditions are not particularly limited. For example, it can be heated at a temperature of 50 to 140 ° C. for 1 to 60 minutes. The coating composition of the present invention has curability at a low temperature, and desired performance such as scratch resistance and weather resistance can be obtained without heating at a high temperature (for example, 100 ° C. or higher). It is preferable to heat at a temperature of ˜100 ° C. In addition, since the coating composition of the present invention is cured even with active energy rays, desired performance such as scratch resistance and weather resistance can be obtained without heating for a long time. Preferably, it is more preferable to heat for 1 to 20 minutes.

Examples of the active energy ray include ultraviolet light, visible light, and laser light (near infrared light, visible light laser, ultraviolet laser, etc.). Its dose is usually 100~5,000mJ / cm ^2, preferably preferably in the range of 300~3,000mJ / cm ^2. As the active energy ray irradiation source, conventionally used ones such as ultra-high pressure, high pressure, medium pressure, low pressure mercury lamp, FusionUV electrodeless lamp, chemical lamp, carbon arc lamp, xenon lamp, metal halide A light source obtained from each light source such as a lamp, a fluorescent lamp, a tungsten lamp, and sunlight, a light beam in a visible region cut by an ultraviolet cut filter, and various lasers having an oscillation line in the visible region can be used. In addition, a pulsed light emission type active energy ray irradiation apparatus can also be used. The irradiation atmosphere may be air or an inert gas atmosphere such as carbon dioxide gas or nitrogen gas.

  Hereinafter, the present invention will be described in more detail with reference to examples. “Part” and “%” indicate “part by mass” and “% by mass” unless otherwise specified.

Production Example 1 of Isosorbide Diacrylate
A 1 L four-necked flask was charged with 146 g (1 mol) of isosorbide, 144 g (2 mol) of acrylic acid, 0.15 g (0.0014 mol) of p-benzoquinone, 1.5 g (0.015 mol) of methanesulfonic acid, and 700 g of toluene, and air was introduced. The mixture was heated to 120 ° C. in an oil bath and stirred for 10 hours. The reaction was carried out while distilling off the water that emerged as the reaction proceeded. After completion of the reaction, the mixture was cooled to room temperature and washed with 100 ml of distilled water to remove the catalyst. Thereafter, 0.025 g of hydroquinone was added and the solvent was removed under reduced pressure to obtain a pale yellow viscous liquid.

  This was analyzed by 1H-NMR, liquid chromatography (HPLC), and GC-mass spectrum, and confirmed to be the following isosorbide diacrylate.

Production and production example 2 of hydroxyl group-containing resin (B)
In a reaction vessel equipped with a stirrer, a thermometer, a reflux condenser, and a dropping device, 80 parts of xylene were charged and stirred at 100 ° C. while blowing nitrogen gas, and 10 parts of styrene, 40 parts of methyl methacrylate, i- A mixture of 8 parts of butyl methacrylate, 20 parts of n-butyl acrylate, 20 parts of 2-hydroxyethyl acrylate, 2 parts of acrylic acid and 4 parts of 2,2′-azobisisobutyronitrile was dropped at a uniform rate over 3 hours. The mixture was further aged for 2 hours at the same temperature. Thereafter, a mixture of 10 parts of xylene and 0.5 parts of 2,2′-azobisisobutyronitrile was added dropwise to the reaction vessel over 1 hour, and aged for 1 hour after completion of the addition, containing a hydroxyl group having a nonvolatile content of 55%. An acrylic resin (B-1) solution was obtained. The obtained hydroxyl group-containing acrylic resin (B-1) had an acid value of 15.6 mgKOH / g, a hydroxyl value of 96.6 mgKOH / g, a weight average molecular weight of 20,000, and a glass transition temperature of 14.6 ° C. It was.

Production Example 3
In a reaction vessel equipped with a stirrer, a thermometer, a reflux condenser, and a dropping device, 80 parts of xylene were charged and stirred at 100 ° C. while blowing nitrogen gas, and 10 parts of styrene, 33 parts of methyl methacrylate, i- A mixture of 8 parts of butyl methacrylate, 27 parts of n-butyl acrylate, 20 parts of 2-hydroxyethyl acrylate, 2 parts of acrylic acid and 4 parts of 2,2′-azobisisobutyronitrile was dropped at a uniform rate over 3 hours. The mixture was further aged for 2 hours at the same temperature. Thereafter, a mixture of 10 parts of xylene and 0.5 parts of 2,2′-azobisisobutyronitrile was added dropwise to the reaction vessel over 1 hour, and aged for 1 hour after completion of the addition, containing a hydroxyl group having a nonvolatile content of 55%. An acrylic resin (B-2) solution was obtained. The obtained hydroxyl group-containing acrylic resin (B-2) had an acid value of 15.6 mgKOH / g, a hydroxyl value of 96.6 mgKOH / g, a weight average molecular weight of 20,000, and a glass transition temperature of 3.9 ° C. It was.

Production Example 4
In a reaction vessel equipped with a stirrer, a thermometer, a reflux condenser, and a dropping device, 80 parts of xylene were charged and stirred at 100 ° C. while blowing nitrogen gas, and 20 parts of styrene, 40 parts of methyl methacrylate, i- A mixture of 18 parts of butyl methacrylate, 20 parts of 2-hydroxyethyl acrylate, 2 parts of acrylic acid and 4 parts of 2,2′-azobisisobutyronitrile was added dropwise at a uniform rate over 3 hours, and further at the same temperature for 2 hours. Aged. Thereafter, a mixture of 10 parts of xylene and 0.5 parts of 2,2′-azobisisobutyronitrile was added dropwise to the reaction vessel over 1 hour, and aged for 1 hour after completion of the addition, containing a hydroxyl group having a nonvolatile content of 55%. An acrylic resin (B-3) solution was obtained. The obtained hydroxyl group-containing acrylic resin (B-3) had an acid value of 15.6 mgKOH / g, a hydroxyl value of 96.6 mgKOH / g, and a weight average molecular weight of 20,000. The glass transition temperature was 45.6 ° C.

Production Production Example 5 of Compound (C-1)
In a reaction vessel equipped with a stirrer, a thermometer, a reflux condenser, and a dropping device, 33.8 parts of methoxypropyl acetate, 50.0 parts of an isocyanurate cycloadduct of hexamethylene diisocyanate (NCO content 21%), dibutyltin dilaurate 0 A mixture of .02 parts and hydroquinone monomethyl ether 0.2 parts was charged. The mixture was heated to 50 ° C. with stirring. Subsequently, Plaxel FA-2D (trade name, manufactured by Daicel Chemical Industries, General Formula (I), R ¹ is a hydrogen atom, and R ² is an ethylene group while the temperature of the mixture does not exceed 60 ° C. , 85.2 parts of caprolactone-modified hydroxyethyl acrylate wherein n is 2) is added dropwise over 8 hours, and the mixture is further stirred at 60 ° C. for 1 hour to obtain a compound (C-1-1) solution having a nonvolatile content of 80%. Obtained. The isocyanate equivalent of the obtained compound (C-1-1) was 2,731, the unsaturated group equivalent was 546, and the weight average molecular weight was 1,366.

Production Examples 6-8
In Production Example 5, compounds (C-1-2) to (C-1-4) solutions were obtained in the same manner as in Production Example 1 except that the formulation was changed to the formulation shown in Table 1. Table 1 shows the isocyanate equivalent, unsaturated group equivalent, and weight average molecular weight of the obtained compound. Also, (Note 1) to (Note 2) in Table 1 are as follows.

(Note 1) Plaxel FA-1: trade name, manufactured by Daicel Chemical Industries, caprolactone-modified hydroxyethyl acrylate in which R ¹ is a hydrogen atom, R ² is an ethylene group, and n is 1 in the general formula (I) ( Note 2) Plaxel FM-3: trade name, manufactured by Daicel Chemical Industries, caprolactone-modified hydroxyethyl methacrylate in which R ¹ is a methyl group, R ² is an ethylene group, and n is 3 in the general formula (I).

Preparation Example 1 of Coating Composition
15.8 parts of isosorbide diacrylate obtained in Production Example 1, 95.6 parts of a 55% solution of hydroxyl group-containing acrylic resin (B-1) obtained in Production Example 2 (nonvolatile content 52.6 parts), production 26.4 parts of an 80% solution of the compound (C-1-1) obtained in Example 5 (non-volatile content: 21.1 parts), 10.5 parts of isocyanurate cycloadduct of hexamethylene diisocyanate (NCO content: 21%), Darocur 1173 (Merck Japan, trade name, photopolymerization initiator) 3.0 parts, TINUVIN 400 (BASF, trade name, light stabilizer) 1.0 part, TINUVIN 292 (BASF, trade name, (UV absorber) 0.5 part was mixed uniformly, and the non-volatile content was adjusted with butyl acetate. 1 was obtained. Coating composition No. The equivalent ratio of the total amount of isocyanate groups (NCO) of the component (C-1) and component (C-2) in 1 and the hydroxyl group (OH) of the component (B) is NCO / OH = 0.77, The equivalent ratio of the isocyanate group (NCO) of the component (C-1) to the isocyanate group (NCO) of the component (C-2) is NCO of the component (C-1) / NCO of the component (C-2). = 0.12. According to the following test plate preparation method, the obtained coating composition No. A test plate coated with No. 1 was prepared and subjected to various evaluations. The evaluation results are shown in Table 2.

Examples 2-10, Comparative Examples 1-3
In Example 1, the composition of each component was changed to the composition shown in Table 2, and in the same manner as in Example 1, the coating composition No. 2-13 were obtained. According to the following test plate preparation method, a test plate coated with each coating composition was prepared and subjected to various evaluations. The evaluation results are shown in Table 2. In addition, the compounding quantity of Table 2 shows the compounding quantity of a non volatile matter. Further, (Note 3) to (Note 4) in Table 2 are as follows.
(Note 3) Irgacure 819: manufactured by BASF, trade name, photopolymerization initiator (Note 4) Black paste: 52.4 parts of methoxypropyl acetate, 15 parts of carbon black, DISPERBYK-2001 (dispersant manufactured by Big Chemie Japan, An active ingredient (46%) (32.6 parts) was mixed to prepare a mill base, and dispersed in a bead mill for 60 minutes to obtain a black paste having a pigment concentration of 15% by weight.

(Test plate production method)
Each coating composition was air spray-coated on a polymethyl methacrylate resin plate so that the dry film thickness was 20 μm. Subsequently, after preheating at 50 ° C. for 3 minutes, the activation energy at an irradiation dose of 1,500 mJ / cm ² using an ultrahigh pressure mercury lamp for each of an air atmosphere (test plate I) and a nitrogen atmosphere (test plate II). Irradiated with rays. Subsequently, each test plate was obtained by drying at 90 ° C. for 10 minutes.

Further, polypropylene NX-280AK (manufactured by Mitsubishi Oil Chemical Co., Ltd., plate thickness: 3.2 mm) was subjected to trichloroethane vapor degreasing for 1 minute and then dried at 80 ° C. for 10 minutes. Next, “SOFLEX No. 1000” (manufactured by Kansai Paint Co., Ltd., polyolefin-containing conductive organic solvent primer primer) was applied as a primer with a dry film thickness of 15 μm and set at room temperature for 3 minutes. Silver "(Kansai Paint Co., Ltd., trade name, polyester urethane one-component organic solvent-based metallic paint) is electrostatically coated to a dry film thickness of 15 μm, set at room temperature for 3 minutes, and then coated It was. Each coating composition was air spray-coated on this object so that the dry film thickness was 20 μm. Subsequently, after preheating at 50 ° C. for 3 minutes, an active energy ray was irradiated at an irradiation amount of 1,500 mJ / cm ^{2 in} an air atmosphere using an ultra-high pressure mercury lamp, followed by drying at 90 ° C. for 10 minutes for each test. A plate (test plate III) was obtained.

(Solvent resistance)
Apply a load of about 1 kg / cm ^{2 to} the coated surface of test plate I and test plate III with gauze soaked in acetone, and reciprocate between about 5 cm in length. The number of times until the coating surface was marked was counted, and the solvent resistance was evaluated according to the following criteria.
A: No trace even at 200 round trips B: Trace at 100-199 round trips C: Trace at 50-99 round trips D: Traces at 49 round trips or less.

(Curability of coating surface)
The curability of the coating film surfaces of Test Plate I and Test Plate II was evaluated by the tackiness of the coating film surface and the presence or absence of scratches by the nails.
A: No tack and no damage by nails B: No tack, but scratched by nails C: Tack

(Abrasion resistance)
The test plate I and the test plate III were subjected to a Taber abrasion test (abrasion wheel CF-10P, load 500 g, 100 rotations) according to ASTM D1044. About the coating film before and behind a test, the glossiness of each coating surface was measured according to the specular glossiness (60 degree | times) of JISK5600-4-7 (1999). The glossiness after the test with respect to the glossiness before the test was determined as a gloss retention (%) and evaluated according to the following criteria.
A: Gloss retention 90% or more B: Gloss retention 80% or more and less than 90% C: Gloss retention 60% or more and less than 80% D: Gloss retention 20% or less.

(Finishing)
The test plate III was visually observed, and the degree of occurrence of metallic unevenness was evaluated according to the following criteria.
A: Almost no metallic unevenness is observed B: Slight metallic unevenness is observed C: Many metallic unevenness is recognized

(Weatherability)
The test plate I was subjected to a weather resistance test for 2000 hours using a sunshine weatherometer in accordance with JIS K 5600-7-8 (1999). The appearance and adhesion of the test plate after the test was evaluated:
<Appearance>
A: No abnormality was observed on the coating film surface, and the color difference ΔE based on JIS Z 8730 was less than 0.3 in the initial and post-test test plates.
B: Slight yellowing was observed, and the color difference ΔE according to JIS Z 8730 was 0.3 or more and less than 0.5 in the test plate in the initial stage and after the test, and there was no problem when it was made into a product. .
C: Yellowing was recognized in the coating film, and the color difference ΔE based on JIS Z 8730 was 0.5 or more and less than 0.8 in the test plate at the initial stage and after the test.
D: Yellowing of the coating film was observed, and the test plate in the initial stage and after the test had a color difference ΔE based on JIS Z 8730 of 0.8 or more or cracked.

<Adhesiveness>
After making 100 2mm x 2mm gobangs on the coated surface according to JIS K 5600-5-6 (1990) on each coated surface, affixing adhesive tape to the surface and removing it rapidly, The number of remaining Gobang eyes coatings was evaluated.
A: remaining number / total number = 100/100 C: remaining number / total number = 99 to 90/100 D: remaining number / total number = 89 or less / 100

(In the above formula, R ¹ represents a ( meth) acryloyl group.) Although not particularly limited, it can be produced from isosorbide using the following (meth) acrylate reaction. Isosorbide can be produced by a known production method. That is, it can be produced by dehydrating sorbitol by the action of various dehydration catalysts, particularly strong acid catalysts. Examples of the catalyst include sulfuric acid, paratoluenesulfonic acid, methanesulfonic acid, hydrochloric acid, phosphoric acid and the like. These dehydration reactions are generally performed efficiently in water and other organic solvents such as toluene and xylene. As the (meth) acrylate reaction, a method of esterifying a hydroxyl group using (meth) acrylic acid halide or (meth) acrylic anhydride, or an ester of a lower alcohol of (meth) acrylic acid such as MMA is used. Transesterification, DCC (N, N'-dicyclohexylcarbodiimide), WSCD (water-soluble carbodiimide) and other carbodiimide-based dehydration condensing agents using (meth) acrylic acid dehydration condensation method, or using acid catalyst For example, a dehydrating condensation method. If necessary, a known polymerization inhibitor may be used so that polymerization does not proceed during production or during product storage.

Claims (9)

A coating composition comprising an isosorbide di (meth) acrylate (A), a hydroxyl group-containing resin (B), and an isocyanate group-containing compound (C). The coating composition according to claim 1, wherein the hydroxyl group-containing resin (B) is a hydroxyl group-containing acrylic resin. The coating composition according to claim 1 or 2, wherein the glass transition temperature of the hydroxyl group-containing resin (B) is 0 ° C or higher. The isocyanate group-containing compound (C) is obtained by reacting a caprolactone-modified hydroxyalkyl (meth) acrylate with a polyisocyanate compound, and contains a radical polymerizable unsaturated group having an isocyanate equivalent weight in the range of 300 to 3,800. The coating composition of any one of Claims 1 thru | or 3 containing a compound (C-1). The isocyanate group-containing compound (C) further contains an isocyanate compound (C-2) other than the compound (C-1) in addition to the compound (C-1). The coating composition as described in 2. Furthermore, the coating composition of any one of Claim 1 thru | or 5 containing a photoinitiator (D). Furthermore, the coating composition of any one of the Claims 1 thru | or 6 containing radically polymerizable unsaturated group containing compound (E) other than the said isosorbide di (meth) acrylate (A) and a compound (C-1). Furthermore, the coating composition of any one of Claim 1 thru | or 7 containing a coloring material. The coated article obtained by coating the coating composition of any one of Claims 1-8.