JPS6131148B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to ultraviolet curable compositions, more specifically,
The present invention relates to a composition that is transparent or semi-transparent before irradiation with ultraviolet rays, but provides a white coating film with high hiding properties when irradiated with ultraviolet rays. Conventionally, in order to obtain a white coating film with hiding properties,
Pigments with high hiding power (such as titanium oxide and zinc white) are used mixed with the vehicle. It is generally difficult to cure such white paints with ultraviolet light, and special paint formulations and curing methods are required. As a result of repeated research into obtaining a white coating film with hiding properties without using pigments, the present inventors found that
A combination of a compound having a large UV-curable acryloyl group or methacryloyl group and a compound that does not have a polymerizable unsaturated group that undergoes radical polymerization by UV rays or has poor radical polymerizability and is difficult to react with an acryloyl group or methacryloyl group. The present invention was completed based on the discovery that a white coating film with concealing properties can be obtained by applying ultraviolet rays to the solvent-containing composition of the combination. The gist of the present invention is group A (compounds having a number average molecular weight of 2,000 or less, a polymerizable unsaturated group equivalent of 750 or less, and two or more acryloyl groups or methacryloyl groups), group B (compounds having a number average molecular weight of 5,000 or more), and does not have an acryloyl group or a methacryloyl group), a photosensitizer and a solvent, and the weight ratio of the above groups A and B is 10≧Group A/
The present invention relates to an ultraviolet curable composition which satisfies Group B≧0.1, has a solvent content of 10 to 80% by weight, and is capable of forming a coating film with hiding properties by irradiating ultraviolet rays in this solvent-containing state. Specific examples of compounds having two or more acryloyl groups or methacryloyl groups, which are Group A compounds used in the present invention, include the following. (1) Esterified products of acrylic acid or methacrylic acid. For example, ethylene glycol di(meth)acrylate, propylene glycol di(meth)
acrylate, 1,6-hexanediol di(meth)acrylate, diethylene glycol di(meth)acrylate, tetraethylene glycol di(meth)acrylate, trimethylolpropane tri(meth)acrylate, pentaerythritol tetra(meth)acrylate, etc. (2) Obtained by reacting a polyester having two or more carboxyl groups derived from a polybasic acid or its anhydride and a polyhydric alcohol with an acrylic or methacrylic compound having an epoxy group (e.g. glycidyl (meth)acrylate) , a compound having an acryloyl group or a methacryloyl group. Examples of the above-mentioned polybasic acids and their anhydrides include phthalic acid, isophthalic acid, terephthalic acid, tetrahydrophthalic acid, tetrachlorophthalic acid, tetrabromophthalic acid, hexahydrophthalic acid, hymic acid, hexic acid, succinic acid, and maleic acid. Examples include acids such as fumaric acid, adipic acid, sebacic acid, dodecenylsuccinic acid, trimellitic acid, pyromellitic acid, and their anhydrides. The polyhydric alcohol mentioned above is
For example, ethylene glycol, diethylene glycol, propylene glycol, dipropylene glycol, glycerin, trimethylolpropane, 1,3 or 1,4-butanediol,
Examples include 1,6-hexanediol, neopentyl glycol, 1,2,6-hexanetriol, pentaerythritol, sorbitol, bisphenol A, and the like. (3) A compound having an acryloyl group or a methacryloyl group, which is obtained by reacting a compound having two or more epoxy groups with acrylic acid or methacrylic acid. Examples of the above-mentioned compounds having two or more epoxy groups include a condensation polymer of epichlorohydrin and bisphenol A (for example, "Epicote 828" manufactured by Ciel Chemical Co., Ltd.), ethylene glycol diglycidyl ether (trade name "Epicote 828" manufactured by Kyoeisha Yushi Kagaku Kogyo Co., Ltd.), ``Epolite 40E''), polyethylene glycol #200 diglycidyl ether (product name ``Epolite 200E'' manufactured by the company), polyethylene glycol #400 diglycidyl ether (product name ``Epolite 400E'' manufactured by the company),
1,6-hexanediol diglycidyl ether (trade name: "Epolite-1600" manufactured by the same company), neopentyl glycol diglycidyl ether (trade name "Epolite-1500NP" manufactured by the same company), trimethylolpropane triglycidyl ether (trade name: manufactured by the same company) "Epolite-100MF") etc. (4) A compound having an acryloyl group or a methacryloyl group, which is obtained by reacting a polyvalent isocyanate compound with an esterified product of acrylic acid or methacrylic acid having a hydroxyl group. Examples of the polyvalent isocyanate compounds include hexamethylene diisocyanate, 2,4-tolylene diisocyanate, 2,6-tolylene diisocyanate, xylylene diisocyanate, 4,4'-methylenebis(phenyl isocyanate), and the like. Further, examples thereof include isocyanates obtained by addition-reacting an excess amount of the polyvalent isocyanate compound with a polyol (for example, trimethylolpropane), polyisocyanates having a biuret structure, polyisocyanates having an allophanate structure, and the like. Examples of the esterified products of acrylic acid or methacrylic acid having a hydroxyl group include 2-hydroxyethyl (meth)acrylate, 2-hydroxypropyl (meth)acrylate, and 2-hydroxybutyl (meth)acrylate. (5) Acryloyl group or methacryloyl group obtained by reacting an isocyanate derivative having a polymerizable double bond (for example, a reaction product of 1 mol of xylylene diisocyanate and 1 mol of 2-hydroxyethyl methacrylate) with an active hydrogen-containing compound. A compound with These A group compounds need to have a number average molecular weight of 2000 or less and a polymerizable unsaturated group equivalent of 750 or less. When the number average molecular weight exceeds 2000 or the equivalent weight of polymerizable unsaturated groups exceeds 750, the whitening phenomenon does not occur significantly even when used in combination with a group B compound. Here, the polymerizable unsaturated group equivalent refers to the number average molecular weight/number of polymerizable unsaturated groups in the Group A compound. In the present invention, the above-mentioned Group A compounds can be used alone or in combination of two or more. Specific examples of the compound having no acryloyl group or methacryloyl group, which is a B group compound used in the present invention, include the following. (1) Solvent-soluble resins such as acrylic resins, polyester resins, polyvinyl butyral resins, ethylene-vinyl acetate copolymer resins, vinyl acetate resins, vinyl chloride resins, and polyamide resins. (2) An unsaturated polyester resin obtained by polymerizing a polybasic acid or its anhydride with a polyhydric alcohol and using maleic anhydride as a component of the polybasic acid. The polybasic acids, their anhydrides and polyhydric alcohols include those mentioned above. (3) An unsaturated acrylic resin obtained by reacting an acrylic polymer prepared by polymerizing an esterified product of acrylic acid or methacrylic acid having a hydroxyl group as one component with maleic anhydride and a compound having an epoxy group. Examples of the esterified product of acrylic acid or methacrylic acid having a hydroxyl group include those mentioned above. Examples of the compound having an epoxy group include butyl glycidyl ether, phenyl glycidyl ether, allyl glycidyl ether, and the like. These B group compounds need to have a number average molecular weight of 5000 or more. When the number average molecular weight is less than 5,000, the whitening phenomenon does not occur significantly even when used in combination with a group A compound. In the present invention, one kind or a mixture of two or more of the above B group compounds can be used. In the composition of the present invention, the above Group A and Group B are used in a weight ratio of 10≧Group A/Group B≧0.1.
Outside this range, the whitening phenomenon of the composition of the present invention will not be noticeable, and the coating film obtained will be too rigid or, on the contrary, too soft to be practical. The photosensitizer used in the present invention may be one used in ordinary ultraviolet curable compositions, such as benzoin, benzoin methyl ether, benzoin isopropyl ether, benzoin butyl ether, benzyl, benzophenone, etc. . The above-mentioned photosensitizers may be used alone or in combination of two or more in a proportion of 0.1 to 20 parts by weight per 100 parts by weight of Group A, as in the case of ordinary ultraviolet curable compositions. The solvent used in the present invention may be any solvent as long as it dissolves Group A and Group B, and is usually a hydrocarbon solvent such as hexane, heptane, cyclohexane, methylcyclohexane, toluene, xylene, petroleum hydrocarbon, or methanol. , alcohol solvents such as ethanol, isopropyl alcohol, butanol, ketone solvents such as acetone, methyl ethyl ketone, methyl isobutyl ketone, cyclohexanone, ether solvents such as ethyl ether, dioxane, cellosolve, ethyl acetate, acetic acid n-
propyl, isopropyl acetate, n-butyl acetate,
One type or a mixture of two or more types of ester solvents such as methyl cellosolve acetate can be used. The above-mentioned solvent is used when subjecting the composition of the present invention to ultraviolet irradiation.
Its presence in the composition is necessary. The amount used varies depending on the types and properties of Group A and Group B, as well as the usage method and conditions of the composition of the present invention, but it is usually present in the composition of the present invention in an amount of 10 to 80% by weight at the time of ultraviolet irradiation. It is preferable to do so. The composition of the present invention has the above-mentioned structure, and provides a white coating film with high hiding properties when irradiated with ultraviolet rays, but can be colored with high hiding properties by appropriately blending pigments or dyes into the composition. It can be said that this is of great industrial significance since it can provide a coating film. In addition, for the purpose of improving the properties of the composition of the present invention and the coating film obtained, compounds having one polymerizable unsaturated group (for example, methyl (meth)acrylate, ethyl (meth)acrylate, butyl (meth)acrylate , acrylic or methacrylic compounds such as 2-ethylhexyl (meth)acrylate, and polyester monoacrylate disclosed in JP-A No. 48-60787). The composition of the present invention can be prepared and cured in the same manner as ordinary ultraviolet curable compositions, and the ultraviolet radiation sources used at this time include ordinary ultra-high pressure mercury lamps, high-pressure mercury lamps, low-pressure mercury lamps, metal halide lamps, Examples include xenon lamps and chemical lamps. As described above, the composition of the present invention is transparent or translucent because it does not contain pigments etc. before irradiation with ultraviolet rays, and gradually whitens as it hardens due to irradiation with ultraviolet rays. Compared to white pigment dispersion compositions, pigments do not block ultraviolet rays and the ultraviolet rays transmit well, so even thick coatings can be cured easily and with high hiding properties. Can provide a white coating. Next, the present invention will be specifically explained with reference to reference examples and examples. In addition, "parts" in the examples means "parts by weight." Reference example 1 Trimethylolpropane in a flask with a stirrer
134 parts of tetrahydrophthalic anhydride, 456 parts of tetrahydrophthalic anhydride, and 30.5 parts of toluene were added, and the mixture was reacted at 150°C for 2 hours. Thereafter, 161.5 parts of butyl acetate and 2 parts of hydroquinone are added, and while stirring at 110°C, a mixture of 426 parts of glycidyl methacrylate, 1 part of hydroquinone, 5 parts of dibutyltin dilaurate and 64 parts of butyl acetate is added dropwise over about 5 hours. Thereafter, the mixture was reacted at 110° C. for 7 hours with stirring to obtain 1280 parts of a resin composition having a resin content of 79% by weight. The resulting resin has a number average molecular weight of 1016 and a polymerizable unsaturated group equivalent of 339, with an average theoretical number of methacryloyl groups per mole of 3. Reference Example 2 A 75% by weight ethyl acetate solution of an addition reaction product of 3 moles of tolylene diisocyanate and 1 mole of trimethylolpropane (product name: "Dismodillary L" manufactured by Sumitomo Bayer Urethane) 875 in a flask equipped with a stirrer.
318 parts of butyl acetate and 0.6 parts of dibutyltin dilaurate were added thereto, and while stirring at room temperature, a mixture of 390 parts of 2-hydroxyethyl methacrylate and 2 parts of hydroquinone was added dropwise over about 2 hours. After the temperature rise due to the reaction heat stopped, the temperature was gradually raised to 80°C, and the reaction was carried out with stirring until no isocyanate groups were observed in the reaction system in the infrared absorption spectrum, resulting in a resin composition 1585.5 with a resin content of 66% by weight. get the part. The resulting resin has a number average molecular weight of 1046 and a polymerizable unsaturated group equivalent weight of 349,
The average theoretical methacryloyl group number per mole is 3. Reference Example 3 Put 1260 parts of toluene into a flask equipped with a stirrer, and while stirring at 100 to 110°C under a nitrogen gas atmosphere, add 630 parts of methyl methacrylate, 594 parts of n-butyl acrylate, 414 parts of 2-hydroxyethyl methacrylate, and 162 parts of styrene. , 36 parts of 2,2'-azobisisobutyronitrile and 18 parts of lauryl mercaptan were added dropwise over about 2 hours, followed by 9 parts of 2,2'-azobisisobutyronitrile and 540 parts of toluene. was added dropwise over about 30 minutes, and then aged at the above temperature for about 1 hour to obtain 3,663 parts of a composition containing 51% by weight of an acrylic polyol having a number average molecular weight of 4,950. Next, tetrahydrophthalic anhydride is added to the above composition.
193 parts of maleic anhydride, 364 parts of allyl glycidyl ether, 2.16 parts of hydroquinone, and 8.76 parts of dibutyltin dilaurate were added, and the mixture was reacted at 110°C under a nitrogen gas atmosphere until the acid value reached 20 or less, resulting in a resin content of 56.7% by weight. 4355 parts of resin composition are obtained. The resulting resin has a number average molecular weight of 6,825 and a polymerizable unsaturated group equivalent weight of 1,950. Example 1 A composition consisting of the formulation shown below was applied to a steel plate using a bar coater, and immediately irradiated with two 2KW high-pressure mercury lamps (H2000L manufactured by Toshiba Corporation) from a distance of 30cm for 3 minutes to form a film with a thickness of 120 to 150μ. Obtain a coating. Table 1 shows the composition and the state of the coating film. Formulation Example 1 Resin composition of Reference Example 1 75 parts 30% by weight ethyl acetate solution of vinyl butyral resin (trade name "Eslec BLS" manufactured by Sekisui Chemical Co., Ltd., degree of polymerization approximately 300) 40 parts Benzoin isopropyl ether 4 parts Ethyl acetate 71 parts Formulation Example 2 46 parts of the resin composition of Reference Example 2 Vinyl butyral resin solution in Formulation Example 1
100 parts benzoin isopropyl ether 3 parts ethyl acetate 10 parts Blending example 3 Resin composition of Reference example 2 122 parts Vinyl butyral resin solution in Blending example 1 40 parts Benzoin isopropyl ether 4 parts Ethyl acetate 54 parts Blending example 4 Resin of Reference example 2 Composition 90 parts Vinyl butyral resin solution in Formulation Example 1 40 parts Benzoin isopropyl ether 3 parts n-butyl acrylate 60 parts Ethyl acetate 10 parts Formulation Example 5 Trimethylolpropane triacrylate 30 parts Vinyl butyral resin solution in Formulation Example 1
100 parts benzoin isopropyl ether 3 parts ethyl acetate 25 parts Blend example 6 Addition reaction product of ethylene glycol diglycidyl ether (1 mol) and methacrylic acid (2 mol) (trade name "epoxy ester" manufactured by Kyoeisha Yushi Kagaku Kogyo)
40E") 60 parts 40% by weight xylene solution of acrylic resin (Mitsubishi Rayon product name "Dyanal BR-50", molecular weight approx. 70,000) 40 parts benzoin isopropyl ether 4 parts ethyl acetate 20 parts xylene 66 parts Mixing example 7 Tri Methylolpropane acrylate 60 parts Acrylic resin solution in Formulation Example 6 40 parts Benzoin isopropyl ether 4 parts Ethyl acetate 20 parts Xylene 66 parts Formulation example 8 Resin composition of Reference Example 2 90 parts Resin composition of Reference Example 3 100 parts Benzoin isopropyl ether 6 parts Ethyl acetate 56 parts [Table]

Claims (1)

[Scope of Claims] 1 Group A (compounds having a number average molecular weight of 2000 or less and a polymerizable unsaturated group equivalent of 750 or less, and having two or more acryloyl groups or methacryloyl groups), Group B (compounds having a number average molecular weight of 5000 or more) and does not have an acryloyl group or a methacryloyl group), a photosensitizer and a solvent, and the weight ratio of the above groups A and B is 10≧Group A/B
1. An ultraviolet curable composition, wherein the composition has a solvent content of 10 to 80% by weight, and is capable of forming a coating film with hiding properties when irradiated with ultraviolet rays in this solvent-containing state.