JP7147396B2 - UV curable coating composition, cured film, coating - Google Patents

Description

The present invention relates to UV-curable coating compositions, cured coatings, and coatings.

Along with the advancement of IT-related technologies such as mobile devices such as smartphones and tablets, digital home appliances such as digital cameras and audio equipment, and communication devices such as wireless devices and modems, the demand for UV-curable coating compositions used in the electronics field is increasing. there is For example, in a smartphone, since a decorative layer having a step of about 20 μm is provided on the cover glass, the coating composition is required to adhere to the step while following the step. Also, in the organic EL device, a coating composition is used as a sealant and can maintain stable light emission characteristics over a long period of time.

An example of a coating composition that has such step followability and flexibility as a subject is, for example, a monomer having an unsaturated double bond, a urethane bond, and an unsaturated double bond at the polymer end. A pressure-sensitive adhesive composition containing a specific amount of a polymer having a bond and a weight average molecular weight of 20,000 or more is known (Patent Document 1). In this technology, flexibility is imparted by lengthening the cross-linking interval of the high molecular weight material, and the adhesive flows well when temperature is applied. This causes problems such as non-uniformity in the thickness of the coating.

JP 2006-104296 A

An object of the present invention is to provide an ultraviolet curable coating composition that has low odor, is hard at room temperature, has excellent fluidity at high temperatures, and exhibits good adhesion to a substrate; a cured film of the coating composition; and to provide a coated article having the cured coating.

The present inventors have focused on the structures of polyurethane (meth)acrylates and (meth)acrylates used in combination, and conducted intensive studies. The inventors have found that an ultraviolet-curable coating composition containing the above-mentioned compounds can solve the above-mentioned problems, and have completed the present invention. That is, the present invention relates to the following UV-curable coating composition, cured coating, and coating.

1. Diisocyanate (a1), diol (a2) and hydroxyl group-containing monofunctional (meth)acrylate (a3), per 1 mol of component (a1), 0.8 to 1 mol of component (a2) and component (a3) UV curable coating composition containing polyurethane (meth)acrylate (A) reacted at 0.05 to 1 mol, cyclic (meth)acrylate (B) having an oxygen atom in the ring, and thiol (C) .

2. 1. The UV-curable coating composition according to the preceding item 1, wherein the component (a2) is a polyester diol.

3. (B) component is (2-methyl-2-ethyl-1,3-dioxolan-4-yl) methyl acrylate, cyclic trimethylolpropane formal acrylate, (3-ethyloxetan-3-yl) methyl acrylate and (3- 3. The UV-curable coating composition according to item 1 or 2, which is one selected from the group consisting of ethyloxetan-3-yl)methyl methacrylate.

4. 4. The UV-curable coating composition according to any one of 1 to 3 above, wherein the content ratio of component (A) and component (B) is (A)/(B)=20/80 to 80/20 in terms of solid weight.

5. 5. The UV-curable coating composition according to any one of the preceding items 1 to 4, wherein the component (C) is a trifunctional thiol and/or a tetrafunctional thiol.

6. 6. The UV-curable coating composition according to any one of the preceding Items 1 to 5, wherein component (C) is 0.1 to 5 parts by weight per 100 parts by weight of components (A) and (B) combined.

7. A cured film of the coating composition according to any one of 1 to 6 above.

8. A coating having the cured coating of item 7 above on at least one side of a substrate.

The UV-curable coating composition according to the present invention has a low odor, is hard at room temperature, has excellent fluidity at high temperatures, and exhibits good adhesion to substrates. Since it has the above effect, the coating composition is used, for example, as a coating agent for polarizing plates, liquid crystal panels and organic EL panels, as an adhesive or sealing agent for light emitting elements, light receiving elements, photoelectric conversion elements and optical transmission related parts. It can be applied to agents, etc., and is particularly suitable as a sealant.

The UV-curable coating composition of the present invention comprises a specific polyurethane (meth)acrylate (A) (hereinafter referred to as component (A)), a cyclic (meth)acrylate (B) having an oxygen atom in the ring (hereinafter referred to as ( B) component) and thiol (C) (hereinafter referred to as (C) component).

Component (A) is a component that provides excellent adhesion to the substrate of the UV-curable coating composition, and also provides excellent fluidity at high temperatures by forming a cured film. Diisocyanate (a1) ( hereinafter referred to as the (a1) component), a diol (a2) (hereinafter referred to as the (a2) component) and a hydroxyl group-containing monofunctional (meth)acrylate (a3) (hereinafter referred to as the (a3) component). be.

Component (a1) is not particularly limited, and examples include 2,4-tolylene diisocyanate, 2,6-tolylene diisocyanate, m-xylylene diisocyanate, tetramethylxylylene diisocyanate, 3-methyldiphenylmethane diisocyanate, 4, Aromatic diisocyanates such as 4-diphenylmethane diisocyanate and 1,5-naphthalene diisocyanate; Aliphatic diisocyanates such as tetramethylene diisocyanate, hexamethylene diisocyanate, trimethylhexamethylene diisocyanate and lysine diisocyanate; Dicyclohexylmethane-4,4'-diisocyanate, isophorone Alicyclic diisocyanates such as diisocyanate, 1,4-cyclohexane diisocyanate, norbornane diisocyanate, cyclohexane-1,4-diylbis(methylene) diisocyanate, hydrogenated xylene diisocyanate, hydrogenated tolylene diisocyanate, and the like, and these are used alone. However, two or more types may be combined. Among them, aliphatic diisocyanates and/or alicyclic diisocyanates are preferred, and alicyclic diisocyanates are more preferred, from the viewpoint of transparency of the cured film.

The (a2) component is not particularly limited, and examples thereof include polyether diols, polyester diols, polycarbonate diols, and the like. These may be used alone or in combination of two or more.

The polyether diol is not particularly limited, and examples thereof include polyethylene glycol, polypropylene glycol, polytetramethylene glycol, and copolymers thereof. These may be used alone or in combination of two or more. Examples of commercially available products include ADEKA POLYETHER POLYOL 1000, ADEKA POLYETHER POLYOL 2000 (manufactured by ADEKA Corporation), and PTMG650, PTMG1000 and PTMG2000 (manufactured by Mitsubishi Chemical Corporation).

The polyester diol is not particularly limited, and examples thereof include polycondensates of diols and polybasic acids. Diols are not particularly limited, and examples include ethylene glycol, diethylene glycol, triethylene glycol, 1,2-propanediol, 1,3-propanediol, 1,3-butanediol, 1,4-butanediol, and neopentyl. glycol, pentanediol, 3-methyl-1,5-pentanediol, 2,2,4-trimethyl-1,3-pentanediol, hexanediol, octanediol, 2,2-diethyl-1,3-propanediol, 2-ethyl-2-butyl-1,3-propanediol, 1,4-cyclohexanedimethanol, ethylene glycol or propylene glycol adducts of bisphenol A, and the like. The polybasic acid is not particularly limited, and examples thereof include dipic acid such as adipic acid, maleic acid, succinic acid, oxalic acid, fumaric acid, malonic acid, glutaric acid, pimelic acid, azelaic acid, sebacic acid, and suberic acid. Basic acids; aromatic polybasic acids such as phthalic anhydride, isophthalic acid, terephthalic acid, 2,6-naphthalenedicarboxylic acid, trimellitic acid and pyromellitic acid; their corresponding anhydrides and their derivatives and dimer acids, water Addition of dimer acid and the like can be mentioned. In the esterification reaction, a known catalyst may be used as necessary. Examples include tin compounds such as dibutyltin oxide and stannous octylate, alkoxy titanium such as tetrabutyl titanate and tetrapropyl titanate, and the like. is mentioned. These may be used alone or in combination of two or more.

The polycarbonate diol is not particularly limited, and examples thereof include diols such as 1,3-propanediol, 1,4-butanediol, 1,5-pentanediol, 1,6-hexanediol, cyclohexanedimethanol, and phosgene. reaction products and the like. These may be used alone or in combination of two or more.

Among the above component (a2), polyester diol is preferable because the cured film is hard at room temperature and has excellent fluidity at high temperature.

The physical properties of the component (a2) are not particularly limited, and for example, the number average molecular weight (polystyrene conversion value by gel permeation chromatography, the same shall apply hereinafter) is usually about 400 to 5000, preferably about 500 to 2000. is. The average number of hydroxyl groups in component (a2) is also not particularly limited, and is usually about 1 to 3, preferably about 1 to 2.

The molar amount of component (a2) used is usually 0.8 to 1 mol, preferably 0.9 to 1 mol, per 1 mol of component (a1). If it is less than 0.8 mol, the fluidity of the cured film at high temperatures tends to be low, and if it exceeds 1 mol, the curability of the cured film at room temperature tends to be low.

Component (a3) is not particularly limited, and examples include 2-hydroxyethyl (meth)acrylate, 2-hydroxypropyl (meth)acrylate, 3-hydroxypropyl acrylate, 3-hydroxybutyl (meth)acrylate, 4-hydroxy Butyl (meth) acrylate, 6-hydroxyhexyl acrylate, 4-hydroxycyclohexyl (meth) acrylate, 5-hydroxycyclooctyl (meth) acrylate, 2-hydroxy-3-phenyloxypropyl (meth) acrylate, pentaerythritol tri(meth) ) acrylate, polyethylene glycol mono(meth)acrylate, polypropylene glycol mono(meth)acrylate and the like. These may be used alone or in combination of two or more. Among them, those having a total carbon number of 5 to 10 are preferable from the viewpoint of the fluidity of the cured film at high temperatures.

The molar amount of component (a3) used is usually 0.05 to 1 mol, preferably 0.2 to 0.7 mol, per 1 mol of component (a1). If it is less than 0.05 mol, the fluidity of the cured film at high temperatures tends to be low, and if it exceeds 1 mol, the curability of the cured film at room temperature tends to be low.

Component (A) is not particularly limited, and is produced by various known methods. ) and then reacting the (A') component with the (a3) component. The reaction conditions are not particularly limited, and usually the temperature is about 60 to 90° C. and the reaction time is about 0.5 to 3 hours.

The component (A) may be produced in the absence of a solvent, but may also be produced in the presence of the component (B), which will be described later.

Other physical properties of component (A) are not particularly limited, but the weight average molecular weight is preferably about 2,000 to 40,000, more preferably about 5,000 to 20,000.

Component (B) is not particularly limited as long as it is a cyclic (meth)acrylate having an oxygen atom in the ring. Examples include (3-ethyloxetane-3-yl)methyl acrylate, (3-ethyloxetane-3 -yl) (meth)acrylates having an oxetane ring such as methyl methacrylate; (2-methyl-2-ethyl-1,3-dioxolan-4-yl)methyl acrylate, (2-oxo-1,3-dioxolan-4-yl) ) methyl methacrylate, 4-(meth)acryloyloxymethyl-2-cyclohexyl-1,3-dioxolane (meth)acrylates having a dioxolane ring; cyclic trimethylolpropane formal acrylate, 1,3-dioxane-5,5-dioxolane Examples thereof include (meth)acrylates having a dioxane ring such as methanol diacrylate. These may be used alone or in combination of two or more. Among them, (2-methyl-2-ethyl-1,3-dioxolan-4-yl)methyl acrylate, cyclic trimethylolpropane formal acrylate, One selected from the group consisting of (3-ethyloxetan-3-yl)methyl acrylate and (3-ethyloxetan-3-yl)methyl methacrylate is preferable, and commercially available products include "MEDOL-10" ((2- methyl-2-ethyl-1,3-dioxolan-4-yl) methyl acrylate, manufactured by Osaka Organic Chemical Industry Co., Ltd.), "Viscoat #200" (cyclic trimethylolpropane formal acrylate, manufactured by Osaka Organic Chemical Industry Co., Ltd.), ( 3-ethyloxetan-3-yl) methyl acrylate (trade name: “OXE-30”, manufactured by Osaka Organic Chemical Industry Co., Ltd.), (3-ethyloxetan-3-yl) methyl methacrylate (trade name: “OXE- 10”, manufactured by Osaka Organic Chemical Industry Co., Ltd.).

The content of component (B) is not particularly limited, but from the viewpoint of excellent fluidity of the cured film at high temperatures, the content ratio with component (A) is (A)/(B) in terms of solid content weight. = about 20/80 to 80/20. From the same point of view, (A)/(B) is preferably about 30/70 to 60/40.

Component (C) is not particularly limited, and various known ones can be used, and examples thereof include monofunctional thiol, polyfunctional thiol, and the like.

The monofunctional thiol is not particularly limited and includes, for example, 1-nonanethiol, tert-nonanethiol, 1-dodecanethiol mercaptan, tert-dodecanethiol and the like.

The polyfunctional thiol is not particularly limited, and examples include 1,2-ethanedithiol, 1,3-propanedithiol, 1,4-butanedithiol, 1,5-pentanedithiol, 1,6-hexanedithiol, 1, 7-heptanedithiol, 1,8-octanedithiol, 1,9-nonanedithiol, triazinedithiol, tetraethylene glycol bis(3-mercaptopropionate), 3-mercaptomethyl-3,5,5-trimethylcyclohexylthiol, Bifunctional thiol such as 1,3-bis(mercaptomethyl)cyclohexane, 1,4-bis(3-mercaptobutyryloxy)butane, tetraethylene glycol-bis(3-mercaptopropionate); triazine trithiol, 1 , 2,3-propanetrithiol, trimethylolpropane tris(3-mercaptopropionate), 1,3,5-tris(3-mercaptobutyloxyethyl)-1,3,5-triazine-2,4, Trifunctional thiols such as 6-(1H,3H,5H)-trione; tetrafunctional thiols such as pentaerythritol tetrakisthioglucolate pentaerythritol tetrakis (3-mercaptopropionate) and pentaerythritol tetrakis (3-mercaptobutyrate) etc.

These may be used alone or in combination of two or more. Among them, polyfunctional thiol is preferable, and trifunctional thiol and/or tetrafunctional thiol are more preferable, pentaerythritol tetrakis (3-mercaptobutyrate) pentaerythritol tetrakis (3 -mercaptobutyrate) is particularly preferred.

The content of component (C) is not particularly limited, but from the viewpoint of excellent fluidity of the cured film at high temperatures, the solid weight is , about 0.1 to 5 parts by weight. From the same point of view, it is preferably about 0.5 to 2 parts by weight.

The UV-curable coating composition of the present invention can be produced by mixing components (A), (B) and (C). There are no particular restrictions on the mixing temperature, the mixing method of each component, and the order of addition.

Moreover, for the purpose of adjusting the viscosity of the coating composition, an organic solvent may be added, if necessary. The organic solvent is not particularly limited, and examples include ethyl acetate, butyl acetate, toluene, xylene, methanol, ethanol, propanol, butanol, acetone, methyl isobutyl ketone, methyl ethyl ketone, cyclohexanone, ethyl cellosolve, propylene glycol monomethyl ether, and diacetone. Alcohol etc. are mentioned. These may be used alone or in combination of two or more.

The UV-curable coating composition of the present invention contains a photopolymerization initiator upon irradiation with UV rays. The photopolymerization initiator is not particularly limited, and examples thereof include photopolymerization initiators such as benzoin compounds, acetophenone compounds, acylphosphine oxide compounds, titanocene compounds, thioxanthone compounds, and oxime ester compounds, and photosensitizers such as amines and quinones. and the like, more specifically, 2,2-dimethoxy-1,2-diphenylethan-1-one, 1-hydroxy-cyclohexylphenylketone, 2-hydroxy-2-methyl-1-phenyl-propane- 1-one, 1-[4-(2-hydroxyethoxy)-phenyl]-2-hydroxy-2-methyl-1-propan-1-one, 2-hydroxy-1-[4-[4-(2- Hydroxy-2-methyl-propionyl)-benzyl]phenyl]-2-methyl-propan-1-one, 2-methyl-1-(4-methylthiophenyl)-2-morpholinopropan-1-one, 2-( dimethylamino)-2-[(4-methylphenyl)methyl]-1-[4-(4-morpholinyl)phenyl]-1-butanone, 2,4,6-trimethylbenzoyldiphenylphosphine oxide, bis(2,4 ,6-trimethylbenzoyl)-phenylphosphine oxide, bis(η ⁵ -2,4-cyclopentadien-1-yl)-bis(2,6-difluoro-3-(1H-pyrrol-1-yl)-phenyl) Titanium, 1,2-octanedione 1-[4-(phenylthio)-2-(o-benzoyloxime)], ethanone 1-[9-ethyl-6-(2-methylbenzoyl)-9H-carbazole-3- yl]-1-(o-acetyloxime) and the like. These may be used alone or in combination of two or more.

The content of the photopolymerization initiator is not particularly limited, but from the viewpoint of the curability of the ultraviolet curable coating composition, it is usually 0.00 per 100 parts by weight of components (A) to (C) in total. About 05 to 15 parts by weight, preferably about 0.5 to 10 parts by weight, more preferably about 0.5 to 5 parts by weight.

The UV-curable coating composition of the present invention may optionally contain a surface modifier, a surfactant, a UV absorber, an antioxidant, a light stabilizer, an inorganic filler, a silane coupling agent, colloidal silica, a leveling agent, Additives such as defoamers, photosensitizers, slip agents, wetting agents, rust inhibitors, and the like may also be included.

The cured film of the present invention is obtained by curing the UV-curable coating composition.

The cured film of the present invention is not particularly limited, and can be obtained by applying the UV-curable coating composition of the present invention to a substrate and irradiating it with UV rays.

The substrate is not particularly limited, and examples thereof include polyethylene terephthalate film (PET film), cycloolefin polymer (COP film), polypropylene film, polybutene film, polybutadiene film, polymethylpentene film, polyvinyl chloride film, and vinyl chloride film. Polymer film, polyethylene naphthalate film, polybutylene terephthalate film, polyurethane film, ethylene vinyl acetate film, ionomer resin film, ethylene/(meth)acrylic acid copolymer film, ethylene/(meth)acrylate copolymer film , polystyrene film, polycarbonate film, polyimide film, fluororesin film, and other plastic films; metal, wood, paper, glass, slate, and the like.

The coating method is not particularly limited, and examples thereof include an applicator, bar coater, roll coater, knife coater, gravure coater and the like. The coating amount of the UV-curable coating composition is also not particularly limited, and is usually applied so that the weight after drying is about 0.1 to 20 g/m ² .

The ultraviolet light source is not particularly limited, and examples thereof include xenon lamps, high-pressure mercury lamps, ultrahigh-pressure mercury lamps, carbon arc lamps, metal halide lamps, chemical lamps, electrodeless lamps, and LED lamps. Also, the irradiation intensity of ultraviolet rays is not particularly limited, and is usually about 100 to 1000 mJ/cm ² . Moreover, after irradiating with ultraviolet rays, it may be heated, if necessary, for the purpose of completely curing.

The coating of the present invention has the cured coating of the present invention on at least one side of a substrate. The substrate, curing method, etc. are the same as described above.

The present invention will be specifically described below with reference to examples, but the present invention is not limited to these examples. In each example, all parts and percentages are by weight unless otherwise specified.

Synthesis Example 1 (Production of component (A-1))
Polyester polyol (reaction product of adipic acid and ethylene glycol, manufactured by DIC Corporation, trade name: "Polylite OD- X-286'') 78.1 parts and isophorone diisocyanate 17.4 parts were charged, the temperature in the system was raised to 40° C., and 0.04 part of tin 2-ethylhexanoate was added. After stirring at 80°C for 1.5 hours, 4.5 parts of 2-hydroxyethyl acrylate, and after 30 minutes, 0.04 parts of tin 2-ethylhexanoate were added to the resulting reactant, and the mixture was stirred at 80°C for another 2 hours. continued. It was confirmed by the IR spectrum that the absorption of the isocyanate group at 2270 cm ⁻¹ had disappeared, and the component (A-1) was obtained. The weight average molecular weight of component (A-1) was 9,000.

Synthesis Example 2 (Production of component (A-2))
Polyester polyol (reaction product of adipic acid and ethylene glycol, manufactured by DIC Corporation, trade name: "Polylite OD- X-286”) 81.5 parts and 1,6-hexanediisocyanate 13.7 parts were charged, the temperature in the system was raised to 40° C., and 0.04 part of tin 2-ethylhexanoate was added. rice field. After stirring at 80°C for 1.5 hours, 4.7 parts of 2-hydroxyethyl acrylate and after 30 minutes, 0.04 parts of tin 2-ethylhexanoate were added to the resulting reactant, and the mixture was stirred at 80°C for another 2 hours. continued. It was confirmed by the IR spectrum that the absorption of the isocyanate group at 2270 cm ⁻¹ had disappeared, and the component (A-2) was obtained. The weight average molecular weight of component (A-2) was 9,000.

Synthesis Example 3 (Production of component (A-3))
A reactor equipped with a stirrer, cooler, dropping funnel, and thermometer was charged with a polyester polyol having a number average molecular weight of 550 (a reaction product of adipic acid and ethylene glycol, manufactured by Mitsui Chemicals, Inc., trade name: "Takelac U -550”) and 26.8 parts of isophorone diisocyanate were charged, the temperature in the system was raised to 40° C., and 0.04 part of tin 2-ethylhexanoate was added. After stirring at 80°C for 1.5 hours, 7.0 parts of 2-hydroxyethyl acrylate and 0.04 parts of tin 2-ethylhexanoate were added to the resulting reactant after 30 minutes, and the mixture was stirred at 80°C for another 2 hours. continued. It was confirmed by the IR spectrum that the absorption of the isocyanate group at 2270 cm ⁻¹ had disappeared, and the component (A-3) was obtained. The weight average molecular weight of component (A-3) was 8,000.

Synthesis Example 4 (Production of component (A-4))
A reactor equipped with a stirrer, cooler, dropping funnel, and thermometer was charged with 71.4 parts of a polyether polyol having a number average molecular weight of 700 (polypropylene glycol, manufactured by Asahi Glass Co., Ltd., trade name: "EXCENOL720"), and isophorone. After charging 22.7 parts of diisocyanate, the system temperature was raised to 40° C., and 0.04 part of tin 2-ethylhexanoate was added. After stirring at 80°C for 1.5 hours, 5.9 parts of 2-hydroxyethyl acrylate and 0.04 part of tin 2-ethylhexanoate were added to the resulting reactant after 30 minutes, and the mixture was stirred at 80°C for another 2 hours. continued. It was confirmed by IR spectrum that the absorption of the isocyanate group at 2270 cm ⁻¹ had disappeared, and component (A-4) was obtained. The weight average molecular weight of component (A-4) was 8,000.

Synthesis Example 5 (Production of component (A-5))
A reactor equipped with a stirrer, cooler, dropping funnel, and thermometer was charged with a polycarbonate polyol having a number average molecular weight of 500 (reactant of 1,6-hexanediol, manufactured by Ube Industries, Ltd., trade name: "UH- 50”) and 28.5 parts of isophorone diisocyanate were charged, the temperature in the system was raised to 40° C., and 0.04 part of tin 2-ethylhexanoate was added. After stirring at 80°C for 1.5 hours, 7.4 parts of 2-hydroxyethyl acrylate and after 30 minutes, 0.04 parts of tin 2-ethylhexanoate were added to the resulting reactant and stirred at 80°C for 2 hours. continued. It was confirmed by IR spectrum that the absorption of the isocyanate group at 2270 cm ⁻¹ had disappeared, and the component (A-5) was obtained. The weight average molecular weight of component (A-5) was 8,000.

Synthesis Example 6 (Production of component (A-6))
Polyester polyol (reaction product of adipic acid and ethylene glycol, manufactured by DIC Corporation, trade name: "Polylite OD- X-286'') 76.0 parts and isophorone diisocyanate 16.9 parts were charged, the temperature in the system was raised to 40° C., and 0.04 part of tin 2-ethylhexanoate was added. After stirring at 80°C for 1.5 hours, 7.1 parts of 2-hydroxyethyl acrylate was added to the resulting reactant, and after 30 minutes, 0.04 part of tin 2-ethylhexanoate was added, and the mixture was further stirred at 80°C for 2 hours. continued. It was confirmed by IR spectrum that the absorption of the isocyanate group at 2270 cm ⁻¹ had disappeared, and the component (A-6) was obtained. The weight average molecular weight of component (A-6) was 10,000.

Synthesis Example 7 (Production of component (A-7))
Polyester polyol (reaction product of adipic acid and ethylene glycol, manufactured by DIC Corporation, trade name: "Polylite OD- X-286'') 80.3 parts and isophorone diisocyanate 17.8 parts were charged, the temperature in the system was raised to 40° C., and 0.04 part of tin 2-ethylhexanoate was added. After stirring at 80°C for 1.5 hours, 1.9 parts of 2-hydroxyethyl acrylate and after 30 minutes, 0.04 parts of tin 2-ethylhexanoate were added to the resulting reactant, and the mixture was stirred at 80°C for another 2 hours. continued. It was confirmed by the IR spectrum that the absorption of the isocyanate group at 2270 cm ⁻¹ had disappeared, and the component (A-7) was obtained. The weight average molecular weight of component (A-7) was 10,000.

Synthesis Example 8 (Production of component (A-8))
Polyester polyol (reaction product of adipic acid and ethylene glycol, manufactured by DIC Corporation, trade name: "Polylite OD- X-286'') 75.7 parts and isophorone diisocyanate 21.0 parts were charged, the temperature in the system was raised to 40° C., and 0.04 part of tin 2-ethylhexanoate was added. After stirring at 80°C for 1.5 hours, 3.3 parts of 2-hydroxyethyl acrylate, and after 30 minutes, 0.04 parts of tin 2-ethylhexanoate were added to the resulting reactant, and the mixture was stirred at 80°C for another 2 hours. continued. It was confirmed by the IR spectrum that the absorption of the isocyanate group at 2270 cm ⁻¹ had disappeared, and the component (A-8) was obtained. The weight average molecular weight of component (A-8) was 11,000.

Synthesis Example 9 (Production of component (A-9))
Polyester polyol (reaction product of adipic acid and ethylene glycol, manufactured by DIC Corporation, trade name: "Polylite OD- X-286'') 77.3 parts and isophorone diisocyanate 17.2 parts were charged, the temperature in the system was raised to 40° C., and 0.04 part of tin 2-ethylhexanoate was added. After stirring at 80°C for 1.5 hours, 5.6 parts of 4-hydroxybutyl acrylate and after 30 minutes, 0.04 parts of tin 2-ethylhexanoate were added to the resulting reaction product, and the mixture was stirred at 80°C for 2 hours. continued. It was confirmed in the IR spectrum that the absorption of the isocyanate group at 2270 cm ⁻¹ had disappeared, and component (A-9) was obtained. The weight average molecular weight of component (A-9) was 10,000.

Comparative Synthesis Example 1 (Production of component (D-1))
Polyester polyol (reaction product of adipic acid and ethylene glycol, manufactured by DIC Corporation, trade name: "Polylite OD- X-286'') 87.1 parts and isophorone diisocyanate 12.9 parts were charged, the temperature in the system was raised to 40° C., and 0.04 part of tin 2-ethylhexanoate was added. After stirring at 80° C. for 1.5 hours, it was confirmed by IR spectrum that absorption of the isocyanate group at 2270 cm ⁻¹ had disappeared, and component (D-1) was obtained. The weight average molecular weight of component (D-1) was 9,000.

Comparative Synthesis Example 2 (Production of component (D-2))
Polyester polyol (reaction product of adipic acid and ethylene glycol, manufactured by DIC Corporation, trade name: "Polylite OD- X-286'') 69.0 parts and isophorone diisocyanate 23.0 parts were charged, the temperature in the system was raised to 40° C., and 0.04 part of tin 2-ethylhexanoate was added. After stirring at 80°C for 1.5 hours, 8.0 parts of 2-hydroxyethyl acrylate, and after 30 minutes, 0.04 parts of tin 2-ethylhexanoate were added to the resulting reaction product, and stirred at 80°C for 2 hours. continued. It was confirmed by the IR spectrum that the absorption of the isocyanate group at 2270 cm ⁻¹ had disappeared, and the component (D-2) was obtained. The weight average molecular weight of component (D-2) was 9,000.

Comparative Synthesis Example 3 (Production of component (D-3))
Polyester polyol (reaction product of adipic acid and ethylene glycol, manufactured by DIC Corporation, trade name: "Polylite OD- X-286'') 61.3 parts and isophorone diisocyanate 20.4 parts were charged, the temperature in the system was raised to 40° C., and 0.04 part of tin 2-ethylhexanoate was added. After stirring at 80° C. for 1.5 hours, 3.6 parts of 2-hydroxyethyl acrylate, 14.7 parts of pentaerythritol triacrylate (manufactured by Osaka Organic Chemical Industry Co., Ltd., Viscoat #300), and further After 30 minutes, 0.04 part of tin 2-ethylhexanoate was added, and stirring was continued at 80°C for an additional 2 hours. It was confirmed by IR spectrum that the absorption of the isocyanate group at 2270 cm ⁻¹ had disappeared, and component (D-3) was obtained. The weight average molecular weight of component (D-3) was 11,000.

Example 1
50 parts of component (A-1), (2-methyl-2-ethyl-1,3-dioxolan-4-yl) methyl acrylate (manufactured by Osaka Organic Chemical Industry Co., Ltd., trade name: "MEDOL-") as component (B) 10'') 50 parts and 1 part of pentaerythritol tetrakis(3-mercaptobutyrate) as component (C) were added and mixed at room temperature to obtain an ultraviolet curable coating composition.

Examples 2-19, Comparative Examples 1-6
By the same method as in Example 1, they were mixed so as to have the compositions shown in Table 1, and UV-curable coating compositions were obtained.

<Odor>
The odor of the UV-curable coating compositions of Examples 1-19 and Comparative Examples 1-6 was sensory evaluated.
(Evaluation criteria)
◯: Almost no odor is sensed.
(triangle|delta): Smell is sensed.
x: A very strong odor is sensed.

<Preparation of covering (1)>
The UV-curable coating composition of Example 1 was applied to the surface of a commercially available polyethylene terephthalate film (trade name: "Cosmoshine A4100", manufactured by Toyobo Co., Ltd.) using an applicator so that the cured film had a thickness of 25 μm. worked. After that, ultraviolet rays were irradiated using a 200 W mercury lamp so that the integrated amount of light was 750 mJ/cm ² to prepare a coating (1). The ultraviolet curable coating compositions of Examples 2 to 19 and Comparative Examples 1 to 6 were also treated in the same manner. The resulting coating (1) was evaluated for adhesion.

<Adhesion>
A cross-cut adhesion test was performed according to JIS K 5600-5-6.
A cellophane tape (trade name “LP-24”, manufactured by Nichiban Co., Ltd.) was adhered to the cured film of the coating (1) by pressing from above with a finger, and then peeled off. Of the 100 squares, the case where the cured film has not peeled off at all squares is 100/100, and the case where all squares have peeled off is 0/100, and the squares where the cured film has not peeled are counted. rice field.

<Preparation of covering (2)>
On the surface of a commercially available polyethylene terephthalate film for separation (trade name: "SP-PET3801BU", manufactured by Mitsui Chemicals, Inc.), the UV-curable coating composition of Example 1 was applied with an applicator so that the film thickness of the cured film was 25 μm. It was coated as After that, ultraviolet rays were irradiated using a 200 W mercury lamp so that the integrated light amount was 750 mJ/cm ² to prepare a coating (2). The ultraviolet curable coating compositions of Examples 2 to 19 and Comparative Examples 1 to 6 were also treated in the same manner. Curability at room temperature and fluidity at high temperature were evaluated for the resulting coating (2).

<Curability at room temperature, fluidity at high temperature>
The polyethylene terephthalate film was peeled off from the coating (2) and cut to 1 cm x 1 cm. The cut cured film was set in a viscoelasticity measuring device (device name: "EXSTAR6000", manufactured by SSI Nanotechnology Co., Ltd.) and cooled with liquid nitrogen until the temperature of the cured film reached 0°C. After that, the temperature was raised under the conditions of a frequency of 1 Hz and a heating rate of 3°C/min, and tan δ at temperatures of 25°C and 50°C was measured.

(Curability at room temperature (tan δ at 25°C))
Curability at room temperature is better as the numerical value is smaller.

(Fluidity at high temperature (tan δ at 50°C))
The fluidity at high temperature is better as the numerical value is larger.

※（Ａ）成分及び（Ｂ）成分の含有量については、固形分重量での（Ａ）成分と（Ｂ）成分との含有比率で示す。
※（Ｃ）成分の含有量については、（Ａ）成分及び（Ｂ）成分の合計１００重量部に対する重量で示す。

* The contents of components (A) and (B) are indicated by the content ratio of components (A) and (B) in terms of solid weight.
* The content of component (C) is indicated by weight relative to a total of 100 parts by weight of components (A) and (B).

Each symbol in Table 1 represents the following components.
<Polyurethane (meth)acrylate>
· A-1: Polyurethane acrylate of Production Example 1 (molar ratio) (a1) component: (a2) component: (a3) component = 1:1:0.5
· A-2: Polyurethane acrylate of Production Example 2 (molar ratio) (a1) component: (a2) component: (a3) component = 1:1:0.5
· A-3: Polyurethane acrylate of Production Example 3 (molar ratio) (a1) component: (a2) component: (a3) component = 1:1:0.5
· A-4: Polyurethane acrylate of Production Example 4 (molar ratio) (a1) component: (a2) component: (a3) component = 1:1:0.5
· A-5: Polyurethane acrylate of Production Example 5 (molar ratio) (a1) component: (a2) component: (a3) component = 1:1:0.5
· A-6: Polyurethane acrylate of Production Example 6 (molar ratio) (a1) component: (a2) component: (a3) component = 1:1:0.8
· A-7: Polyurethane acrylate of Production Example 7 (molar ratio) (a1) component: (a2) component: (a3) component = 1:1:0.2
· A-8: Polyurethane acrylate of Production Example 8 (molar ratio) (a1) component: (a2) component: (a3) component = 1: 0.8: 0.3
· A-9: Polyurethane acrylate of Production Example 9 (molar ratio) (a1) component: (a2) component: (a3) component = 1:1:0.5
・D-1: Polyurethane (meth)acrylate of Comparative Production Example 1 (molar ratio) (a1) component: (a2) component = 1:1.5
・D-2: Polyurethane acrylate of Comparative Production Example 2 (molar ratio) component (a1): component (a2): component (a3) = 1:0.7:0.7
・D-3: Polyurethane acrylate of Comparative Production Example 3 (molar ratio) (a1) component: (a2) component: (a3) component = 1:0.7:0.7
<Cyclic (meth)acrylate having an oxygen atom>
・B-1: (2-methyl-2-ethyl-1,3-dioxolan-4-yl) methyl acrylate (trade name: “MEDOL-10”, manufactured by Osaka Organic Chemical Industry Co., Ltd.)
・ B-2: Cyclic trimethylolpropane formal acrylate (trade name: “Viscoat #200”, manufactured by Osaka Organic Chemical Industry Co., Ltd.)
・ B-3: (3-ethyloxetan-3-yl) methyl methacrylate (trade name: “OXE-10”, manufactured by Osaka Organic Chemical Industry Co., Ltd.)
<(Meth)acrylate without oxygen atom>
・ E-1: isobornyl acrylate ・ E-2: cyclohexyl acrylate <polyfunctional thiol>
・ C-1: Pentaerythritol tetrakis (3-mercaptobutyrate)
・C-2: 1,4-bis(3-mercaptobutyryloxy)butane ・C-3: 1,3,5-tris(3-mercaptobutyloxyethyl)-1,3,5-triazine-2, 4,6-(1H,3H,5H)-trione

Claims (7)

Diisocyanate (a1), diol (a2) and hydroxyl group-containing monofunctional (meth)acrylate (a3), per 1 mol of component (a1), 0.8 to 1 mol of component (a2) and component (a3) Containing 0.05 to 1 mol of reacted polyurethane (meth)acrylate (A), cyclic (meth)acrylate (B) having an oxygen atom in the ring, and thiol (C) ,
(B) component is (2-methyl-2-ethyl-1,3-dioxolan-4-yl) methyl acrylate, cyclic trimethylolpropane formal acrylate, (3-ethyloxetan-3-yl) methyl acrylate and (3- An ultraviolet curable coating composition which is at least one selected from the group consisting of ethyloxetan-3-yl)methyl methacrylate (excluding those containing (meth)acryloylmorpholine) . 2. The UV-curable coating composition according to claim 1, wherein component (a2) is a polyester diol. 3. The UV-curable coating composition according to claim 1, wherein the content ratio of component (A) and component (B) is (A)/(B)=20/80 to 80/20 in terms of solid weight. 4. The UV-curable coating composition according to any one of claims 1 to 3 , wherein component (C) is trifunctional thiol and/or tetrafunctional thiol. The UV-curable coating composition according to any one of claims 1 to 4 , wherein component (C) is 0.1 to 5 parts by weight per 100 parts by weight of components (A) and (B) combined. A cured film of the coating composition according to any one of claims 1 to 5 . A coating having the cured coating of claim 6 on at least one side of a substrate.