Method for producing cured product of resin composition

Abstract

The present invention provides a method for producing a cured product of a resin composition, with which it is possible to obtain a cured product having good physical properties from a resin composition that contains an ethylenically unsaturated group-containing resin. This method for producing a cured product of a resin composition comprises irradiating a resin composition which contains an ethylenically unsaturated group-containing resin (A), an ethylenically unsaturated group-containing monomer (B), and a photopolymerization initiator (C) with light emitted from a light-emitting diode through a colored film so as to cure the resin composition, the colored film having a maximum absorption wavelength within the wavelength range of 400 nm to 1,100 nm, and the light emitted from the light-emitting diode including light (1) in the absorption wavelength range of the photopolymerization initiator (C) and light (2) in the absorption wavelength range of the colored film.

Description

Method for producing cured resin composition

[0001] The present invention relates to a method for producing a cured product of a resin composition containing an ethylenically unsaturated group-containing resin.

[0002] In recent years, deterioration of existing pipes buried underground, such as water pipes, sewer pipes, and electric power pipes, has become increasingly serious, and various methods for repairing these pipes have been proposed. For example, Patent Document 1 discloses a method for repairing existing pipes using a photocuring method, in which an impregnated base material made of fiber or the like is impregnated with a photocurable resin composition and used as a lining material, and also describes the use of a polymerizable resin, such as an unsaturated polyester resin or a vinyl ester resin, dissolved in a solvent such as styrene, as the photocurable resin composition.

[0003] Compared with the heat curing method, the light curing method has a faster curing rate of the resin composition and a shorter construction time, and therefore the construction distance using the light curing method in repair work on existing pipes has been increasing in recent years. Furthermore, the light curing method has advantages over the heat curing method in that the resin composition has less cure shrinkage, is less likely to have poor curing, generates less heat during curing, and emits less flammable gas during curing.

[0004] In the photocuring method, for example, a gallium lamp, a metal halide lamp, a mercury lamp, etc. are used as a light source. Patent Document 2 also proposes a method of irradiating a resin layer with light using a photocuring device that uses a light-emitting diode (LED) that mainly emits ultraviolet light. LEDs generate little heat, are energy-saving, and have a long life, making them excellent light sources.

[0005] JP 2020-82408 A JP 2008-142996 A

[0006] However, in the conventional method of irradiating a resin composition of a lining material with LED light, the resin composition may be poorly cured and the physical properties of the resulting cured product may be insufficient. Therefore, in order to improve the poor curing of the resin composition and to achieve good physical properties of the cured product, we have repeatedly studied a method of curing a resin composition using LED light.

[0007] The present invention has been made under these circumstances, and an object of the present invention is to provide a method for producing a cured product of a resin composition, which can obtain a cured product having good physical properties from a resin composition containing an ethylenically unsaturated group-containing resin.

[0008] The present invention is based on the discovery that, when photocuring a resin composition, two or more specified LEDs with different wavelength ranges are used and light transmitted through a specified colored film is irradiated, thereby obtaining a cured product with good heat resistance and bending properties.

[0009] The present invention provides the following means: [1] A method for producing a cured product of a resin composition comprising an ethylenically unsaturated group-containing resin (A), an ethylenically unsaturated group-containing monomer (B), and a photopolymerization initiator (C) by irradiating a resin composition containing the resin (A), an ethylenically unsaturated group-containing monomer (B), and a photopolymerization initiator (C) with light emitted from a light-emitting diode through a colored film to cure the resin composition, the colored film having a maximum absorption wavelength in the 400 to 1100 nm wavelength range, and the light emitted from the light-emitting diode comprising light (1) in the absorption wavelength range of the photopolymerization initiator (C) and light (2) in the absorption wavelength range of the colored film. [2] A method for producing a cured product of the resin composition of [1], wherein the light irradiated to the resin composition comprises light in the 400 to 1100 nm wavelength range and has at least two peak wavelengths. [3] A method for producing a cured product of the resin composition of [1] or [2], wherein the light-emitting diode emitting light (1) has a peak wavelength in the 250 to 400 nm wavelength range. [4] A method for producing a cured product of the resin composition of any of [1] to [3], wherein the light-emitting diode that emits light (2) has a peak wavelength in a wavelength range of 400 to 1100 nm where the light transmittance of the colored film is 40% or less. [5] A method for producing a cured product of the resin composition of any of [1] to [4], wherein the ethylenically unsaturated group-containing resin (A) is at least one selected from the group consisting of unsaturated polyester resins, vinyl ester resins, (meth)acrylic resins, and urethane (meth)acrylate resins.

[0010] According to the present invention, there is provided a method for producing a cured product of a resin composition, which can obtain a cured product having good physical properties from a resin composition containing an ethylenically unsaturated group-containing resin. The production method of the present invention can be suitably applied to, for example, repair of existing pipes by a photocuring method using a lining material.

[0011] The definitions and meanings of terms and notations used in this specification are as follows. The notation "X to Y" (X and Y are numerical values) means a numerical range with X as the lower limit and Y as the upper limit. For numerical ranges (e.g., ranges of content, etc.), the lower and upper limits described in stages may be independently combined. The lower and upper limits of a numerical range may be replaced with numerical values ​​described in the examples. A light-emitting diode (LED) refers to an LED package, which is a light-emitting electronic component in which a light-emitting element is packaged. The maximum absorption wavelength is the wavelength at which absorbance is maximized, and is not limited to one point in the absorption spectrum, but may exist at two or more points. Among the maximum absorption wavelengths, the wavelength at which absorbance is maximum is called the maximum absorption wavelength. The peak wavelength is the wavelength at which the light-emitting intensity of a light-emitting diode (LED) is maximized, and is not limited to one point in the emission spectrum, but may exist at two or more points. Among the peak wavelengths, the wavelength at which light-emitting intensity is maximum is called the maximum emission wavelength.

[0012] (Meth)acrylic acid is a general term for acrylic acid and methacrylic acid. Similarly, (meth)acrylate is a general term for acrylate and methacrylate, and (meth)acryloyl is a general term for acryloyl and methacryloyl. The weight average molecular weight (Mw) and number average molecular weight (Mn) are standard polystyrene equivalent molecular weights determined by gel permeation chromatography (GPC). Specifically, they are measured by the method described in the Examples below. The molecular weight distribution is a calculated value of Mw / Mn. The acid value of the unsaturated polyester resin is the amount of potassium hydroxide (KOH) [mg] required to neutralize 1 g of unsaturated polyester resin, as measured by a method in accordance with JIS K6901:2008. Specifically, it is measured by the method described in the Examples below. The deflection temperature under load of the cured resin composition can be measured by a method in accordance with JIS K7191-2:2015 Appendix A, specifically, it is measured by the method described in the Examples below. The flexural strength and flexural modulus of the cured resin composition can be measured by a method in accordance with JIS K7171:2016, specifically, by the method described in the examples.

[0013] A method for producing a cured product of a resin composition according to an embodiment of the present invention (hereinafter also referred to as the present embodiment) involves irradiating a resin composition containing an ethylenically unsaturated group-containing resin (A), an ethylenically unsaturated group-containing monomer (B), and a photopolymerization initiator (C) with light emitted from an LED through a colored film to cure the resin composition, the colored film having a maximum absorption wavelength in the wavelength range of 400 to 1100 nm, and the LED emitting light (1) in the absorption wavelength range of the photopolymerization initiator (C) and light (2) in the absorption wavelength range of the colored film. In this way, by using an LED and irradiating the resin composition with light transmitted through a predetermined colored film to photocure the resin composition, a cured product with good heat resistance and bending properties can be produced.

[0014] [Resin Composition] The resin composition of the present embodiment contains an ethylenically unsaturated group-containing resin (A), an ethylenically unsaturated group-containing monomer (B), and a photopolymerization initiator (C). From the viewpoint of good physical properties of the cured product, the total content of the ethylenically unsaturated group-containing resin (A) and the ethylenically unsaturated group-containing monomer (B) in the resin composition is preferably 90% by mass or more and less than 100% by mass, more preferably 92.0 to 99.9% by mass, and even more preferably 95.0 to 99.9% by mass.

[0015] [Ethylenically unsaturated group-containing resin (A)] The ethylenically unsaturated group-containing resin (A) is a resin having polymerizability due to an ethylenically unsaturated group. The ethylenically unsaturated group-containing resin (A) is not particularly limited, but examples thereof include unsaturated polyester resins, vinyl ester resins, (meth)acrylic resins, and urethane (meth)acrylate resins. The ethylenically unsaturated group-containing resin (A) may be used alone or in combination of two or more. Among these, unsaturated polyester resins and vinyl ester resins are preferred, and unsaturated polyester resins are more preferred, since they are likely to produce good cured product properties.

[0016] From the viewpoint of good physical properties of the cured product, the content of the ethylenically unsaturated group-containing resin (A) in the resin composition is preferably 30.0 mass% or more, more preferably 40.0 mass% or more, even more preferably 50.0 mass% or more, relative to 100 mass% in total of the ethylenically unsaturated group-containing resin (A) and the ethylenically unsaturated group-containing monomer (B), and is preferably 80 mass% or less, more preferably 70.0 mass% or less, even more preferably 60.0 mass% or less.

[0017] (Unsaturated polyester resin) The unsaturated polyester resin is preferably a reaction product of a diol and a dibasic acid. The unsaturated polyester resin can be produced by a known synthesis method using a condensation reaction, using a diol and a dibasic acid as reaction raw materials. The unsaturated polyester resin may be used alone or in combination of two or more.

[0018] <Diol> The diol, a reaction raw material for the unsaturated polyester resin, is a compound having two hydroxyl groups per molecule. From the viewpoint of good physical properties of the cured product of the resin composition, for example, an alkanediol, a glycol ether, or the like is preferably used. The diol may be used alone or in combination of two or more. Examples of the alkanediol include ethylene glycol, propylene glycol, 2-methyl-1,3-propanediol, 2,2-dimethyl-1,3-propanediol (neopentyl glycol), 1,2-butanediol, 1,3-butanediol, 1,4-butanediol, 2,3-butanediol, 2-methyl-1,4-butanediol, 1,5-pentanediol, 3-methyl-1,5-pentanediol, 2,4-diethyl-1,5-pentanediol, 1,6-hexanediol, 2- ...ethylene glycol, propylene glycol, 2-methyl-1,3-propanediol, 2,2-dimethyl-1,3-propanediol (neopentyl glycol), 1,2-ethylene glycol, propylene glycol, 2-methyl-1,3-propane Examples of glycol ethers include methyl-1,3-hexanediol, 2,5-dimethyl-2,5-hexanediol, 1,2-octanediol, 1,2-nonanediol, 1,4-cyclohexanediol, 1,8-octanediol, 1,9-nonanediol, 1,2-cyclohexanedimethanol, 1,3-cyclohexanedimethanol, 1,4-cyclohexanedimethanol, 2,2-di(4-hydroxycyclohexyl)propane, and hydrogenated products of bisphenol A, bisphenol F, and bisphenol S. Examples of glycol ethers include diethylene glycol, dipropylene glycol, polyethylene glycol, and polypropylene glycol. Of these, from the viewpoints of availability, ease of handling of the resin composition, production costs, and the like, 2-methyl-1,3-propanediol, ethylene glycol, propylene glycol, neopentyl glycol, diethylene glycol, dipropylene glycol, and hydrogenated bisphenol A are preferred, 2-methyl-1,3-propanediol, propylene glycol, neopentyl glycol, and hydrogenated bisphenol A are more preferred, and propylene glycol and neopentyl glycol are even more preferred.

[0019] <Dibasic Acid> The dibasic acid used as a reaction raw material for the unsaturated polyester resin preferably includes an ethylenically unsaturated group-containing dibasic acid and an ethylenically unsaturated group-free dibasic acid. The dibasic acid also includes an acid anhydride.

[0020] The unsaturated polyester resin is obtained by forming an ester bond through a reaction between 1 mole of a hydroxyl group of a diol and 1 mole of a carboxyl group of a dibasic acid. Therefore, the total amount of the dibasic acid to be blended when producing the unsaturated polyester resin is preferably 80 to 120 parts by mole, more preferably 90 to 110 parts by mole, and even more preferably 95 to 105 parts by mole, per 100 parts by mole of the diol, and may be 100 parts by mole.

[0021] Of the dibasic acids, the ethylenically unsaturated group-containing dibasic acid is preferably 30 to 80 molar parts, more preferably 40 to 70 molar parts, and even more preferably 45 to 65 molar parts relative to 100 molar parts of the diol, from the viewpoint of good physical properties of the cured product of the resin composition. Of the dibasic acids, the ethylenically unsaturated group-free dibasic acid is preferably 20 to 70 molar parts, more preferably 30 to 60 molar parts, and even more preferably 35 to 55 molar parts relative to 100 molar parts of the diol, from the same viewpoint.

[0022] The ethylenically unsaturated group-containing dibasic acid is a compound having two carboxy groups (including acid anhydrides) and at least one ethylenically unsaturated group in one molecule. The ethylenically unsaturated group-containing dibasic acid may be used alone or in combination of two or more. Examples of the ethylenically unsaturated group-containing dibasic acid include maleic anhydride, fumaric acid, itaconic acid, citraconic acid, and chloromaleic acid. Among these, maleic anhydride and fumaric acid are preferred, and maleic anhydride is preferably used, from the viewpoints of availability, ease of handling of the resin composition, and production costs.

[0023] From the viewpoint of good physical properties of the cured product of the resin composition, the content of the ethylenically unsaturated group-containing dibasic acid in the dibasic acid is preferably 20 mol% or more, more preferably 30 mol% or more, even more preferably 40 mol% or more, still more preferably 45 mol% or more, relative to 100 mol% of the dibasic acid, and is preferably 80 mol% or less, more preferably 75 mol% or less, even more preferably 70 mol% or less, and still more preferably 65 mol% or less.

[0024] The ethylenically unsaturated group-free dibasic acid is a compound having two carboxy groups (including acid anhydrides) in one molecule and not having an ethylenically unsaturated group. The ethylenically unsaturated group-free dibasic acid may be used alone or in combination of two or more. Examples of dibasic acids not containing an ethylenically unsaturated group include phthalic anhydride, isophthalic acid, terephthalic acid, succinic acid, adipic acid, sebacic acid, tetrahydrophthalic acid, endomethylenetetrahydrophthalic acid, hexahydrophthalic acid (1,2-cyclohexanedicarboxylic acid, 1,3-cyclohexanedicarboxylic acid, 1,4-cyclohexanedicarboxylic acid), naphthalenedicarboxylic acid, trimellitic acid, pyromellitic acid, chlorendic acid (HETT acid), tetrabromophthalic acid, tetrahydrophthalic anhydride, hexahydrophthalic anhydride, endomethylenetetrahydrophthalic anhydride, succinic anhydride, chlorendic anhydride, trimellitic anhydride, pyromellitic anhydride, 4-methylphthalic acid, 5-methylisophthalic acid, 5-methylterephthalic acid, etc. Of these, isophthalic acid and terephthalic acid are preferred from the viewpoints of availability, ease of handling of the resin composition, production costs, etc.

[0025] From the viewpoint of good physical properties of the cured product of the resin composition, the content of the dibasic acid not containing an ethylenically unsaturated group in the dibasic acid is preferably 20 mol% or more, more preferably 25 mol% or more, even more preferably 30 mol% or more, still more preferably 35 mol% or more, relative to 100 mol% of the dibasic acid, and is preferably 80 mol% or less, more preferably 70 mol% or less, even more preferably 60 mol% or less, and still more preferably 55 mol% or less.

[0026] From the viewpoint of ease of handling and good curing properties of the resin composition, the unsaturated polyester resin preferably has an acid value of 3.0 to 25.0 KOHmg / g, more preferably 5.0 to 20.0 KOHmg / g, and even more preferably 8.0 to 15.0 KOHmg / g.

[0027] From the viewpoints of ease of handling of the resin composition and good physical properties of the cured product, the weight average molecular weight (Mw) of the unsaturated polyester resin is preferably 5,000 to 20,000, more preferably 7,000 to 17,000, and even more preferably 9,000 to 15,000. From the same viewpoint, the number average molecular weight (Mn) of the unsaturated polyester resin is preferably 1,000 to 7,000, more preferably 2,000 to 6,000, and even more preferably 3,000 to 5,000. From the same viewpoint, the molecular weight distribution (Mw / Mn) of the unsaturated polyester resin is preferably 1.00 to 15.00, more preferably 1.50 to 10.00, and even more preferably 2.00 to 5.00.

[0028] (Vinyl ester resin) The vinyl ester resin is preferably a reaction product of an epoxy compound and an unsaturated monobasic acid. The vinyl ester resin may be a reaction product of reaction raw materials including an epoxy compound and an unsaturated monobasic acid, and, if necessary, a bisphenol compound, an unsaturated polybasic acid, etc. The vinyl ester resin using an epoxy compound and an unsaturated monobasic acid as reaction raw materials can be produced by applying a known synthesis method using an addition reaction. The obtained vinyl ester resin is diluted with an ethylenically unsaturated group-containing monomer (B) as necessary. The vinyl ester resin may be used alone or in combination of two or more types.

[0029] <Epoxy Compound> The epoxy compound used as a reaction raw material for the vinyl ester resin is a compound having at least two, preferably two, epoxy groups per molecule. One type of epoxy compound may be used alone, or two or more types may be used in combination. Examples of epoxy compounds include bisphenol A epoxy resins, bisphenol F epoxy resins, bisphenol S epoxy resins, bisphenol AF epoxy resins, tert-butylcatechol epoxy resins, naphthalene epoxy resins, naphthol epoxy resins, anthracene epoxy resins, glycidyl ester epoxy resins, biphenyl epoxy resins, linear aliphatic epoxy resins, epoxy resins having a butadiene structure, alicyclic epoxy resins, heterocyclic epoxy resins, spiro ring-containing epoxy resins, cyclohexanedimethanol epoxy resins, and naphthylene ether epoxy resins. Among these, bisphenol A epoxy resins, bisphenol F epoxy resins, bisphenol S epoxy resins, and bisphenol AF epoxy resins are preferred, with bisphenol A epoxy resins being preferred, from the standpoints of availability, ease of handling of the resin composition, and production costs.

[0030] The epoxy compound preferably has an epoxy equivalent of 170 to 1,000, more preferably 170 to 500, and even more preferably 170 to 300, from the viewpoints of ease of synthesis of the vinyl ester resin and good curability of the resin composition.

[0031] <Unsaturated monobasic acid> The unsaturated monobasic acid is preferably a monocarboxylic acid having an ethylenically unsaturated group. The unsaturated monobasic acid may be used alone or in combination of two or more. Examples of the unsaturated monobasic acid include (meth)acrylic acid, crotonic acid, cinnamic acid, etc. Among these, from the viewpoint of ease of synthesis of the vinyl ester resin and good curability of the resin composition, (meth)acrylic acid and crotonic acid are preferred, (meth)acrylic acid is more preferred, and from the viewpoint of chemical resistance, methacrylic acid is even more preferred.

[0032] When the vinyl ester resin is a reaction product of an epoxy compound and an unsaturated monobasic acid, it is obtained by forming an ester bond by reacting 1 mole of the epoxy group of the epoxy compound with 1 mole of the carboxy group of the unsaturated monobasic acid. The amount of unsaturated monobasic acid used in producing the vinyl ester resin is preferably 30 mole parts or more, more preferably 40 mole parts or more, and even more preferably 50 mole parts or more of the carboxy group of the unsaturated monobasic acid per 100 mole parts of the epoxy group of the epoxy compound, from the viewpoint of good curability of the resin composition. Furthermore, from the viewpoint of making the viscosity of the resin composition easy to handle, it is preferably 120 mole parts or less, more preferably 110 mole parts or less, and even more preferably 105 mole parts or less. The amount may be 100 mole parts per 100 mole parts of the epoxy group of the epoxy compound.

[0033] <Bisphenol Compound> The vinyl ester resin preferably contains a bisphenol compound as a reaction raw material. The bisphenol compound may be used alone or in combination of two or more. Examples of the bisphenol compound include bisphenol A, bisphenol AP, bisphenol AF, bisphenol B, bisphenol BP, bisphenol C, bisphenol E, bisphenol F, bisphenol G, bisphenol M, bisphenol S, bisphenol P, bisphenol PH, bisphenol TMC, and bisphenol Z. Among these, from the viewpoints of availability, production cost, and viscosity of the resin composition that is easy to handle, bisphenol A, bisphenol E, bisphenol F, and bisphenol S are preferred, and bisphenol A, bisphenol E, and bisphenol F are more preferred, and from the viewpoints of corrosion resistance, versatility, and cost, bisphenol A is even more preferred.

[0034] When a bisphenol compound is contained as a reaction raw material for the vinyl ester resin, the total amount of the unsaturated monobasic acid and the bisphenol compound to be blended in producing the vinyl ester resin is preferably 80 to 120 parts by mole, more preferably 90 to 110 parts by mole, and even more preferably 95 to 105 parts by mole, per 100 parts by mole of epoxy groups of the epoxy compound, and may be 100 parts by mole.

[0035] When a bisphenol compound is contained as a reaction raw material for the vinyl ester resin, the amount of the bisphenol compound to be blended in producing the vinyl ester resin is preferably 10 to 70 parts by mole, more preferably 20 to 60 parts by mole, and even more preferably 25 to 50 parts by mole, per 100 parts by mole of epoxy groups of the epoxy compound, from the viewpoint of good physical properties of a cured product of the resin composition.

[0036] The vinyl ester resin may contain an unsaturated polybasic acid as a reaction raw material. The unsaturated polybasic acid is a compound having at least two carboxy groups (including acid anhydrides) and at least one unsaturated group per molecule. The unsaturated polybasic acid may be used alone or in combination of two or more. Examples of unsaturated polybasic acids include maleic anhydride, fumaric acid, itaconic acid, citraconic acid, chloromaleic acid, succinic acid, glutaric acid, adipic acid, sebacic acid, phthalic acid, tetrahydrophthalic acid, and hexahydrophthalic acid. Among these, from the viewpoints of availability, ease of handling of the resin composition, and production costs, maleic anhydride, fumaric acid, succinic acid, glutaric acid, and adipic acid are preferred, with succinic acid, fumaric acid, and maleic anhydride being more preferred, and fumaric acid being even more preferred.

[0037] When an unsaturated polybasic acid is contained as a reaction raw material for the vinyl ester resin, the amount of the unsaturated polybasic acid to be blended in producing the vinyl ester resin is preferably 0.5 to 15 parts by mole, more preferably 1 to 10 parts by mole, and even more preferably 3 to 8 parts by mole, per 100 parts by mole of the epoxy groups of the epoxy compound, from the viewpoint of good physical properties of the cured product of the resin composition.

[0038] From the viewpoint of ease of handling and good curing properties of the resin composition, the vinyl ester resin preferably has an acid value of 3.0 to 50.0 KOHmg / g, more preferably 5.0 to 40.0 KOHmg / g, and even more preferably 10.0 to 35.0 KOHmg / g.

[0039] From the viewpoints of ease of handling of the resin composition and good physical properties of the cured product, the weight average molecular weight (Mw) of the vinyl ester resin is preferably 300 to 20,000, more preferably 500 to 10,000, and even more preferably 700 to 5,000. From the same viewpoint, the number average molecular weight (Mn) of the vinyl ester resin is preferably 200 to 15,000, more preferably 400 to 5,000, and even more preferably 600 to 3,000. From the same viewpoint, the molecular weight distribution (Mw / Mn) of the vinyl ester resin is preferably 1.00 to 5.00, more preferably 1.00 to 3.00, and even more preferably 1.10 to 2.50.

[0040] ((Meth)acrylic resin) The (meth)acrylic resin is preferably a copolymer of a (meth)acrylic acid alkyl ester and a hydroxyl group-containing (meth)acrylate. A known synthesis method using addition polymerization can be applied to produce the (meth)acrylic resin by copolymerizing a (meth)acrylic acid alkyl ester and a hydroxyl group-containing (meth)acrylate. The copolymer may be a random copolymer or a block copolymer. The (meth)acrylic resin may be used alone or in combination of two or more types.

[0041] <(Meth)acrylic acid alkyl ester> In the (meth)acrylic acid alkyl ester, which is a structural unit of the (meth)acrylic resin, the number of carbon atoms in the alkyl group of the alkyl ester moiety is preferably 1 to 20, more preferably 1 to 12, even more preferably 1 to 8, and still more preferably 4 to 8. The (meth)acrylic acid alkyl ester may be used alone or in combination of two or more types. Examples of (meth)acrylic acid alkyl esters include methyl (meth)acrylate, ethyl (meth)acrylate, n-butyl (meth)acrylate, isobutyl (meth)acrylate, tert-butyl (meth)acrylate, n-propyl (meth)acrylate, n-hexyl (meth)acrylate, 2-ethylhexyl (meth)acrylate, n-octyl (meth)acrylate, isodecyl (meth)acrylate, lauryl (meth)acrylate, cetyl (meth)acrylate, stearyl (meth)acrylate, cyclohexyl (meth)acrylate, and isobornyl (meth)acrylate.

[0042] <Hydroxyl Group-Containing (Meth)acrylate> The hydroxyl group-containing (meth)acrylate, which is a structural unit of the (meth)acrylic resin, is a compound having a hydroxyl group and an acryloyl group. The hydroxyl group-containing (meth)acrylate may be used alone or in combination of two or more types. Examples of the hydroxyl group-containing (meth)acrylate include 4-hydroxybutyl (meth)acrylate, 5-hydroxypentyl (meth)acrylate, 6-hydroxyhexyl (meth)acrylate, 8-hydroxyoctyl (meth)acrylate, caprolactone-modified 2-hydroxyethyl (meth)acrylate, diethylene glycol (meth)acrylate, polyethylene glycol (meth)acrylate, 1-(2-hydroxyethyl) 2-(2-methacryloyloxyethyl) phthalate, N-methylol ( Examples of the hydroxyl group-containing (meth)acrylate include primary hydroxyl group-containing (meth)acrylates such as (meth)acrylamide; secondary hydroxyl group-containing (meth)acrylates such as 2-hydroxypropyl (meth)acrylate, 2-hydroxybutyl (meth)acrylate, 2-hydroxy-3-phenoxypropyl (meth)acrylate, 3-chloro-2-hydroxypropyl (meth)acrylate, and 2-hydroxy-3-phenoxypropyl (meth)acrylate; and tertiary hydroxyl group-containing (meth)acrylates such as 2,2-dimethyl-2-hydroxyethyl (meth)acrylate. Of these, primary hydroxyl group-containing (meth)acrylates are preferred, and 2-hydroxyethyl (meth)acrylate is preferably used, from the viewpoints of availability, ease of handling of the resin composition, and production costs.

[0043] In terms of good physical properties of the cured resin composition, the blending ratio of the (meth)acrylic acid alkyl ester and the hydroxyl group-containing (meth)acrylate when producing a (meth)acrylic resin copolymer is preferably 60.0 to 99.9 parts by mole, more preferably 80.0 to 99.8 parts by mole, and even more preferably 90.0 to 99.7 parts by mole of the (meth)acrylic acid alkyl ester per 100 parts by mole of the total of the (meth)acrylic acid alkyl ester and the hydroxyl group-containing (meth)acrylate.

[0044] (Urethane (meth)acrylate resin) The urethane (meth)acrylate resin is preferably a polyurethane having a (meth)acryloyloxy group. The urethane (meth)acrylate resin can be produced by a known synthesis method. For example, an ethylenically unsaturated group-containing oligomer can be obtained by reacting a polyisocyanate with a polyhydroxy compound or a polyhydric alcohol, and then reacting the unreacted isocyanato group with a hydroxyl group-containing (meth)acrylic compound and, if necessary, a hydroxyl group-containing allyl ether compound. The urethane (meth)acrylate resin may be used alone or in combination of two or more types.

[0045] [Ethylenically unsaturated group-containing monomer (B)] The ethylenically unsaturated group-containing monomer (B) is a monomer having polymerizability due to an ethylenically unsaturated group. Examples of the ethylenically unsaturated group include a vinyl group (including an allyl group) and a (meth)acryloyl group. The ethylenically unsaturated group-containing monomer (B) may be used alone or in combination of two or more.

[0046] Examples of the monomer having a vinyl group include styrene derivatives such as styrene, p-chlorostyrene, vinyltoluene, α-methylstyrene, dichlorostyrene, divinylbenzene, tert-butylstyrene, vinylbenzyl butyl ether, vinylbenzyl hexyl ether, and divinylbenzyl ether; vinyl acetate, diallyl fumarate, diallyl phthalate, and triallyl isocyanurate.

[0047] Examples of monomers having a (meth)acryloyl group include (meth)acrylic acid, monofunctional (meth)acrylates, polyfunctional (meth)acrylates, acryloylmorpholine, 2-hydroxyethyl(meth)acrylamide, 2-hydroxyethyl-N-methyl(meth)acrylamide, and 3-hydroxypropyl(meth)acrylamide.

[0048] Examples of monofunctional (meth)acrylates include methyl (meth)acrylate, ethyl (meth)acrylate, n-butyl (meth)acrylate, isobutyl (meth)acrylate, tert-butyl (meth)acrylate, 2-ethylhexyl (meth)acrylate, lauryl (meth)acrylate, cyclohexyl (meth)acrylate, benzyl (meth)acrylate, stearyl (meth)acrylate, tridecyl (meth)acrylate, phenoxyethyl (meth)acrylate, ethylene glycol monomethyl ether (meth)acrylate, ethylene glycol monoethyl ether (meth)acrylate, ethylene glycol monobutyl ether (meth)acrylate, and ethylene glycol monohexyl ether (meth)acrylate. acrylate, ethylene glycol mono-2-ethylhexyl ether (meth)acrylate, diethylene glycol monomethyl ether (meth)acrylate, diethylene glycol monoethyl ether (meth)acrylate, diethylene glycol monobutyl ether (meth)acrylate, diethylene glycol monohexyl ether (meth)acrylate, diethylene glycol mono-2-ethylhexyl ether (meth)acrylate, dicyclopentenyl (meth)acrylate, dicyclopentenyloxyethyl (meth)acrylate, tricyclodecanyl (meth)acrylate, dimethylaminoethyl (meth)acrylate, caprolactone-modified 2-hydroxyethyl (meth)acrylate, and allyl (meth)acrylate.

[0049] Examples of polyfunctional (meth)acrylates include alkanediol di(meth)acrylates such as ethylene glycol di(meth)acrylate, 1,2-propylene glycol di(meth)acrylate, 1,3-butylene glycol di(meth)acrylate, 1,4-butylene glycol di(meth)acrylate, neopentyl glycol di(meth)acrylate, and 1,6-hexanediol di(meth)acrylate; diethylene glycol di(meth)acrylate, dipropylene glycol di(meth)acrylate, triethylene glycol di(meth)acrylate, tetraethylene glycol di(meth)acrylate, polyethylene glycol di(meth)acrylate, and polytetramethylene glycol di(meth)acrylate. and polyoxyalkylene glycol di(meth)acrylates such as these, as well as trimethylolpropane di(meth)acrylate, glycerin di(meth)acrylate, pentaerythritol di(meth)acrylate, trimethylolpropane tri(meth)acrylate, glycerin tri(meth)acrylate, pentaerythritol tri(meth)acrylate, pentaerythritol tetra(meth)acrylate, dipentaerythritol hexa(meth)acrylate, pentaerythritol diacrylate monostearate, 1,3-bis((meth)acryloyloxy)-2-hydroxypropane, ethoxylated bisphenol A di(meth)acrylate, and tris-(2-(meth)acryloxyethyl)isocyanurate.

[0050] Of these, from the viewpoints of availability, good physical properties of the cured product of the resin composition, production costs, and the like, preferred ethylenically unsaturated group-containing monomer (B) are styrene, methyl (meth)acrylate, phenoxyethyl (meth)acrylate, benzyl (meth)acrylate, dicyclopentenyl (meth)acrylate, dicyclopentenyloxyethyl (meth)acrylate, diethylene glycol di(meth)acrylate, triethylene glycol di(meth)acrylate, and tetraethylene glycol di(meth)acrylate, and styrene and phenoxyethyl (meth)acrylate are preferably used.

[0051] From the viewpoint of good physical properties of the cured product, the content of the ethylenically unsaturated group-containing monomer (B) in the resin composition is preferably 20.0 to 70.0 mass%, more preferably 30.0 to 60.0 mass%, and even more preferably 40.0 to 50.0 mass%, relative to 100 mass% in total of the ethylenically unsaturated group-containing resin (A) and the ethylenically unsaturated group-containing monomer (B).

[0052] [Photopolymerization initiator (C)] The photopolymerization initiator (C) initiates the polymerization reaction of the resin composition. By irradiating a resin composition containing the photopolymerization initiator (C) with light in the absorption wavelength range of the photopolymerization initiator (C), the ethylenically unsaturated group-containing resin (A) and the ethylenically unsaturated group-containing monomer (B) are copolymerized, resulting in a cured resin composition. As the photopolymerization initiator (C), a polymerization initiator that generates radicals upon light irradiation is preferred, and from the viewpoint of reactivity, an intramolecular cleavage-type photopolymerization initiator that does not require a hydrogen donor is more preferred. The photopolymerization initiator (C) may be used alone or in combination of two or more types.

[0053] Examples of the photopolymerization initiator (C) include benzoin and its alkyl ethers such as benzoin, benzoin methyl ether, and benzoin ethyl ether; acetophenones such as acetophenone, 2,2-dimethoxy-2-phenylacetophenone, 1,1-dichloroacetophenone, and 4-(1-tert-butyldioxy-1-methylethyl)acetophenone; α-hydroxyalkylphenones such as 1-hydroxycyclohexyl phenyl ketone and 2-hydroxy-2-methyl-1-phenyl-propan-1-one; anthraquinones such as 2-methylanthraquinone, 2-amylanthraquinone, 2-tert-butylanthraquinone, and 1-chloroanthraquinone; 2,4-dimethylthioxanthone, 2,4-diisopropylthioxanthone, and 2-chlorothioxanthone; ketals such as acetophenone dimethyl ketal and benzil dimethyl ketal; benzophenones such as benzophenone, 4-(1-tert-butyldioxy-1-methylethyl)benzophenone and 3,3',4,4'-tetrakis(tert-butyldioxycarbonyl)benzophenone; morpholines such as 2-methyl-1-[4-(methylthio)phenyl]-2-morpholino-propan-1-one, 2-benzyl-2-dimethylamino-1-(4-morpholinophenyl)butan-1-one and 2-benzyl-2-dimethylamino-1-(4-morpholinophenyl)-butan-1-one; acylphosphine oxides such as phenylbis(2,4,6-trimethylbenzoyl)phosphine oxide; and xanthones.

[0054] Among these, the photopolymerization initiator (C) is preferably one that absorbs light irradiated by a general ultraviolet light-emitting diode (UV-LED) to generate radicals, and 2,2-dimethoxy-2-phenylacetophenone, phenylbis(2,4,6-trimethylbenzoyl)phosphine oxide, and 1-hydroxycyclohexyl phenyl ketone are preferred. In a preferred embodiment of the present invention, two types of initiators, 2,2-dimethoxy-2-phenylacetophenone and phenylbis(2,4,6-trimethylbenzoyl)phosphine oxide, are used in combination.

[0055] From the viewpoint of appropriately promoting curing of the resin composition, the total content of the photopolymerization initiator (C) in the resin composition is preferably 0.001 to 15.0 parts by mass, more preferably 0.01 to 5.0 parts by mass, and even more preferably 0.10 to 1.0 part by mass, relative to 100 parts by mass of the total of the ethylenically unsaturated group-containing resin (A) and the ethylenically unsaturated group-containing monomer (B).

[0056] [Other Components] The resin composition may contain other components in addition to the ethylenically unsaturated group-containing resin (A), the ethylenically unsaturated group-containing monomer (B), and the photopolymerization initiator (C). The other components can be added within a range that does not impair the effects of the present invention. Examples of the other components include additives such as other resins, polymerization inhibitors, catalysts, thixotropes, curing accelerators, thickening aids, curing retarders, surfactants, interface modifiers, wetting and dispersing agents, antifoaming agents, leveling agents, coupling agents, light stabilizers, waxes, flame retardants, plasticizers, fillers, internal mold release agents, low-shrinkage agents, toners, viscosity reducers, anti-separation agents, and compatibilizers.

[0057] The polymerization inhibitor can be used to suppress the progress of the polymerization reaction of the resin composition. In this embodiment, the resin composition preferably contains a polymerization inhibitor. As the polymerization inhibitor, known ones can be used, and examples thereof include hydroquinone, methylhydroquinone, trimethylhydroquinone, phenothiazine, catechol, 4-tert-butylcatechol, copper naphthenate, etc. One type of polymerization inhibitor may be used alone, or two or more types may be used in combination.

[0058] The resin composition can be produced by mixing the ethylenically unsaturated group-containing resin (A), the ethylenically unsaturated group-containing monomer (B), and the photopolymerization initiator (C). The other components may be added and mixed as needed.

[0059] The order of mixing is not particularly limited. For example, the resin composition can be obtained by mixing and dissolving the ethylenically unsaturated group-containing resin (A) in the ethylenically unsaturated group-containing monomer (B), adding the photopolymerization initiator (C) and optionally other components, and mixing them. The mixing method is not particularly limited, and can be carried out using, for example, a disperser, a planetary mixer, a kneader, or the like. The kneading temperature is preferably 10 to 40°C, more preferably 15 to 30°C, and from the viewpoint of ease of mixing, etc., even more preferably 20 to 30°C.

[0060] The resin composition of this embodiment can also be used to obtain a cured product with good physical properties when combined with a fiber substrate. Fiber types for the fiber substrate include, from the viewpoint of mechanical strength, so-called reinforcing fibers such as organic fibers such as amide, alanide, vinylon, polyester, and phenol, carbon fibers, glass fibers, metal fibers, and ceramic fibers, as well as composite fibers thereof. The fiber substrate may be a single fiber or a combination of two or more fibers. Among these, aramid fibers, carbon fibers, and glass fibers are preferred, and glass fibers are more preferred from the viewpoints of strength, availability, cost, and the like, with light-transmitting glass fibers and polyester fibers being even more preferred.

[0061] Examples of the form of the fiber substrate include sheets, chopped strands, chopped fibers, milled fibers, etc. Examples of sheets include those formed by aligning multiple reinforcing fibers in one direction, bidirectional fabrics such as plain weave and twill weave, multiaxial fabrics, non-crimp fabrics, nonwoven fabrics, mats, knits, braids, and paper made from reinforcing fibers, etc. The form of the fiber substrate may be one type alone or two or more types in combination, and may be a single layer or a multi-layer laminate.

[0062] [Colored Film] The colored film has a maximum absorption wavelength in the wavelength range of 400 to 1100 nm and transmits light emitted from an LED. The light transmitted through the colored film is irradiated onto a resin composition. It is presumed that the light energy absorbed by the colored film having such light absorption properties is converted into thermal energy, and the temperature of the resin composition to which the heat is transferred increases, improving the curability of the resin composition during photocuring and resulting in a cured product with good physical properties.

[0063] The wavelength range of the maximum absorption wavelength of the colored film is more preferably 460 nm or more, even more preferably 480 nm or more, still more preferably 500 nm or more, and more preferably 1000 nm or less, even more preferably 900 nm or less, and still more preferably 850 nm or less.

[0064] The colored film preferably has a wavelength range of 400 to 1100 nm in which light transmittance is 40% or less, from the viewpoint of absorbing light in the wavelength range of 400 to 1100 nm to generate heat, and allowing the photopolymerization initiator in the resin composition to absorb the light and thereby obtain a cured product with good physical properties. For colored films, light transmittance, which is relative to absorption, was used as an index for ease of measurement. A light transmittance of 40% or less can be said to indicate a sufficiently high light absorptance in that wavelength range.

[0065] The colored film is not particularly limited as long as it has the above-mentioned light absorption and transmittance. As the colored film, for example, a cellophane film is preferred, and a blue, red, green, yellow, or other cellophane film is more preferred, and a blue or red cellophane film is even more preferred. The colored film may be used alone or in combination of two or more types. From the viewpoint of efficient light irradiation of the resin composition, the thickness of the cellophane film is preferably 1 μm or more, more preferably 10 μm or more, even more preferably 15 μm or more, and is preferably 500 μm or less, more preferably 100 μm or less, and even more preferably 30 μm or less.

[0066] The colored film is placed on the surface of the resin composition that is irradiated with light, and may or may not be in contact with the resin composition. Preferably, the colored film is placed so that heat generated in the colored film is transmitted to the resin composition. The colored film may be placed via a solid or liquid. For example, when the resin composition is cured using a mold, the colored film may be placed in a glass mold so as to be in contact with the resin composition, or may be placed so as to be attached to the outer glass surface of the glass mold.

[0067] [Light-Emitting Diode (LED)] In the method for producing a cured resin composition according to this embodiment, light emitted from an LED is transmitted through a colored film and irradiated to cure the resin composition. The LED contains light (1) in the absorption wavelength range of the photopolymerization initiator (C) and light (2) in the absorption wavelength range of the colored film. By irradiating the resin composition with light from the LED corresponding to the respective absorption wavelengths of the photopolymerization initiator (C) and the colored film in the resin composition, a cured product with excellent physical properties can be obtained. Therefore, the light irradiated to the resin composition preferably contains light in the wavelength range of 400 to 1100 nm and has at least two peak wavelengths. The wavelength range of the light irradiated to the resin composition preferably includes the maximum absorption wavelength of the colored film, more preferably 460 nm or more, even more preferably 480 nm or more, even more preferably 500 nm or more, and more preferably 1000 nm or less, even more preferably 900 nm or less, and even more preferably 850 nm or less.

[0068] From the viewpoint of promoting the polymerization reaction of the resin composition by the photopolymerization initiator (C), the LED that emits light (1) preferably exhibits maximum emission intensity in the wavelength range of 250 to 400 nm. This wavelength range can be appropriately set corresponding to the maximum absorption wavelength of the photopolymerization initiator (C). In a preferred embodiment of the present invention, the maximum absorption wavelength of phenylbis(2,4,6-trimethylbenzoyl)phosphine oxide used as the photopolymerization initiator (C) is 366 nm, and an LED with a peak wavelength of 385 nm is used. The LED that emits light (1) may be composed of a single light-emitting element or may have multiple light-emitting elements, and may be mounted on an LED irradiator. Light (1) may include part or all of the absorption wavelength range of the photopolymerization initiator (C).

[0069] The LED that emits light (2) preferably has a peak wavelength in a wavelength range that includes the maximum absorption wavelength of the colored film, from the viewpoint of providing irradiation light that allows the light energy absorbed by the colored film to be efficiently converted into thermal energy. From the same viewpoint, the LED that emits light (2) preferably has a peak wavelength in a wavelength range of 400 to 1100 nm where the light transmittance of the colored film is 40% or less. The LED that emits light (2) may be composed of a single light-emitting element or may have multiple light-emitting elements, and may be mounted on an LED irradiator. The light (2) may include part or all of the absorption wavelength range of the dye (D). The light-emitting element that emits light (1) and the light-emitting element that emits light (2) may be packaged in a single LED, or may be packaged in different LEDs.

[0070] According to the manufacturing method of this embodiment, even if the total integrated light amount of light (1) and light (2) irradiated from the LEDs to the resin composition is approximately the same as the integrated light amount when only light (1) is irradiated, the cured product properties of the resin composition can be improved. When there are multiple LEDs emitting light (1) and light (2), these LEDs may be mounted on the same LED irradiator and configured to emit light simultaneously or switchably. Furthermore, the LED emitting light (1) and the LED emitting light (2) may be mounted on different LED irradiators.

[0071] The irradiance of each of the light (1) and the light (2) is not particularly limited and is set appropriately depending on the shape and thickness of the resin composition, the equipment environment of the manufacturing device for the cured product, etc. The irradiance of the light (1) is preferably 1.0 mW / cm from the viewpoint of improving the curability of the resin composition and obtaining good physical properties of the cured product. ２ More preferably, 5.0 mW / cm ２ More preferably, 20.0 mW / cm ２ From the viewpoint of the heat resistance and energy efficiency of the LED irradiator, it is preferably 1000 mW / cm ２ or less, more preferably 500 mW / cm ２ More preferably, 100 mW / cm or less ２ The irradiance of the light (2) is preferably 1.0 mW / cm from the viewpoint of increasing the temperature during photocuring and obtaining good physical properties of the cured product. ２ More preferably, 5.0 mW / cm ２ More preferably, 20.0 mW / cm ２ From the viewpoint of the heat resistance and energy efficiency of the LED irradiator, it is preferably 1000 mW / cm ２ or less, more preferably 500 mW / cm ２ More preferably, 100 mW / cm or less ２ The following is the result.

[0072] The irradiation time of the light (1) and the light (2) applied to the resin composition is set appropriately taking into consideration the integrated light amount and the irradiance, and is, for example, preferably about 1 second to 60 minutes, more preferably 10 to 50 minutes, and even more preferably 20 to 40 minutes.

[0073] The cumulative amount of light irradiated by the light (1) onto the resin composition is preferably 0.01 J / cm from the viewpoint of sufficient curing of the resin composition. ２ More preferably, 0.1 J / cm ２ More preferably, 1.0 J / cm ２ or more, and preferably 2000 J / cm ２ or less, more preferably 1000 J / cm ２ More preferably, 500 J / cm or less ２ From the same viewpoint, the cumulative light amount of the light (2) irradiated onto the resin composition is preferably 0.01 J / cm ２ More preferably, 0.1 J / cm ２ More preferably, 1.0 J / cm ２ or more, and preferably 2000 J / cm ２ or less, more preferably 1000 J / cm ２ More preferably, 500 J / cm or less ２ From the same viewpoint, the total integrated light amount of the light irradiated onto the resin composition by the light (1) and the light (2) is preferably 0.02 J / cm or less. ２ More preferably, 0.2 J / cm ２ More preferably, 2.0 J / cm ２ or more, and preferably 4000 J / cm ２ or less, more preferably 2000 J / cm ２ More preferably, 1000 J / cm or less ２ The following is the result.

[0074] The method of irradiating the resin composition with light (1) and light (2) using an LED is not particularly limited. Irradiation with light (1) and light (2) may be performed simultaneously, sequentially, or continuously, or irradiation with light (1) and light (2) may be performed multiple times. From the viewpoint of efficiently producing a cured product by shortening the curing time, it is preferable to perform irradiation with light (2) before irradiation with light (1), or to perform irradiation with light (1) and irradiation with light (2) simultaneously, and it is more preferable to perform irradiation with light (1) and irradiation with light (2) simultaneously.

[0075] It is also preferable that the entire resin composition be irradiated with light as evenly as possible. From the viewpoint of efficiently producing a cured product by shortening the curing time, it is preferable to irradiate the resin composition with light from multiple LEDs simultaneously. The LED light irradiation on the resin composition may be direct irradiation through a colored film, or, for example, the resin composition may be cast into a light-transmitting mold such as glass, and the irradiation may be performed through a colored film placed on the inside or outside of the glass surface.

[0076] [Physical Properties of Cured Product] According to the method for producing a cured product of the resin composition of this embodiment, the heat resistance and bending properties of the cured product of a resin composition containing an ethylenically unsaturated group-containing resin (A), an ethylenically unsaturated group-containing monomer (B), and a photopolymerization initiator (C) can be improved by irradiating the resin composition with light from an LED. Regarding the heat resistance of the cured product, the deflection temperature under load is preferably 65.0°C or higher, more preferably 70.0°C or higher, and even more preferably 75.0°C or higher.

[0077] Regarding the mechanical strength of the cured product, the flexural strength is preferably 90 MPa or more, more preferably 92 MPa or more, and even more preferably 95 MPa or more, and the flexural modulus is preferably 2800 MPa or more, more preferably 2850 MPa or more, and even more preferably 2900 MPa or more.

[0078] The present invention will be specifically described below based on examples, but the present invention is not limited to the following examples.

[0079] [Synthesis of Ethylenically Unsaturated Group-Containing Resin (A)] Unsaturated polyester resins (a1) and (a2) and vinyl ester resins (b1) and (b2) were synthesized as the ethylenically unsaturated group-containing resin (A). The physical properties of the ethylenically unsaturated group-containing resin (A) were measured as follows. The measurement results are shown in Table 1.

[0080] [Acid Value] In accordance with JIS K6901:2008 "Partial Acid Value (Indicator Titration Method)," the acid value was determined by measuring the mass of potassium hydroxide required to neutralize the acid components in the measurement sample using a mixed indicator of bromothymol blue and phenol red with an "Autoburette UCB-2000" (manufactured by Hiranuma Sangyo Co., Ltd.) Note that for the vinyl ester resins (b1) and (b2), the measurement sample was a mixture with the reactive diluent (ethylenically unsaturated group-containing monomer (B)) obtained in each Synthesis Example.

[0081] [Weight-average molecular weight (Mw), number-average molecular weight (Mn), and molecular weight distribution (Mw / Mn)] The weight-average molecular weight Mw and number-average molecular weight Mn of the unsaturated polyester resin were measured by gel permeation chromatography (GPC) under the following conditions and calculated as standard polystyrene equivalent molecular weights. The molecular weight distribution Mw / Mn was calculated from the values ​​of the number-average molecular weight Mn and the weight-average molecular weight Mw.

[0082] <Measurement conditions> Apparatus: High-performance liquid chromatograph "Prominence" (manufactured by Shimadzu Corporation) Column: "Shodex LF-804" (manufactured by Resonac Corporation) Detector: Differential refractometer "Shodex RI-71S" (manufactured by Resonac Corporation) Column temperature: 40°C Sample: 0.2% by mass solution of unsaturated polyester resin in tetrahydrofuran Developing solvent: tetrahydrofuran Flow rate: 1.0 mL / min

[0083] Synthesis Example 1 A 3 L four-neck separable flask equipped with a thermometer, a stirrer, a gas inlet tube, and a reflux condenser was charged with 224.6 g of propylene glycol (27.5 parts by mole relative to 100 parts by mole of total diols) as diols, 810.5 g of neopentyl glycol (2,2-dimethyl-1,3-propanediol) (72.5 parts by mole relative to 100 parts by mole of total diols), 472.6 g of isophthalic acid (26.5 parts by mole relative to 100 parts by mole of diols), 356.6 g of terephthalic acid (20.0 parts by mole relative to 100 parts by mole of diols), and 563.1 g of maleic anhydride (53.5 parts by mole relative to 100 parts by mole of diols), and the mixture was subjected to a condensation reaction at 215° C. for 10 hours under a nitrogen gas atmosphere to obtain an unsaturated polyester resin (a1).

[0084] Synthesis Example 2 An unsaturated polyester resin (a2) was obtained in the same manner as in Synthesis Example 1, except that the raw material composition shown in Table 1 was used.

[0085] Synthesis Example 3: 1512 g of "Epomic R140P" (a bisphenol A-type epoxy resin manufactured by Mitsui Chemicals, Inc., epoxy equivalent: 188) as an epoxy compound and 429 g of bisphenol A (47 moles per 100 moles of epoxy groups in the epoxy compound) were placed in a 5 L four-neck separable flask equipped with a thermometer, a stirrer, a gas inlet tube, and a reflux condenser. The mixture was stirred and mixed and heated to 80°C. Next, 3.9 g of triethylamine (manufactured by Daicel Corporation) was added as a catalyst, and the mixture was heated to 145°C and reacted for 1 hour under a nitrogen gas atmosphere. The epoxy equivalent of the epoxy compound was measured in accordance with JIS K7236:2001. The reaction product was then cooled to 110°C, and 429 g (10% by mass based on the total amount of the components) of styrene, which was an ethylenically unsaturated group-containing monomer (B), was added as a reactive diluent. Furthermore, 0.04 g of copper naphthenate (0.0019 parts by mass per 100 parts by mass of the epoxy compound, bisphenol compound, and unsaturated monobasic acid) and 1.3 g of trimethylhydroquinone (0.056 parts by mass per 100 parts by mass of the epoxy compound, bisphenol compound, and unsaturated monobasic acid) were used as polymerization inhibitors, and 6.9 g of 2,4,6-tris(dimethylaminomethyl)phenol ("Seikuol TDMP," manufactured by Seiko Chemical Co., Ltd., purity over 95% by mass) was used as an esterification catalyst (0.3 parts by mass per 100 parts by mass of the epoxy compound, bisphenol compound, and unsaturated monobasic acid) was added, and the mixture was heated to 110°C. Then, 365 g of methacrylic acid (53 moles per 100 moles of the total epoxy groups of the epoxy compound) was added dropwise over 30 minutes, followed by heating to 130°C and reaction for 2 hours to produce vinyl ester resin (b1). The reaction product was cooled to 90°C, and 0.13 g (0.003 mass% based on the total amount of the blended components) of hydroquinone as a polymerization inhibitor was added, and 1,546 g (36 mass% based on the total amount of the blended components) of styrene, which is the ethylenically unsaturated group-containing monomer (B), was added as a reactive diluent, to obtain a mixture of vinyl ester resin (b1) and styrene (mass ratio 54.0 / 46.0).

[0086] Synthesis Example 4 In a 5 L four-neck separable flask equipped with a thermometer, a stirrer, a gas inlet tube, and a reflux condenser, 1950 g of Epomic R140P as an epoxy compound was heated to 80° C., and 407 g (10 mass % based on the total mass of the components) of phenoxyethyl methacrylate, which is the ethylenically unsaturated group-containing monomer (B), as a reactive diluent, 0.04 g of 5% copper naphthenate (0.0014 parts by mass relative to 100 parts by mass of the epoxy compound and the unsaturated monobasic acid), 0.9 g of methylhydroquinone (0.03 parts by mass relative to 100 parts by mass of the epoxy compound and the unsaturated monobasic acid), and 1.6 g of trimethylhydroquinone (0.057 parts by mass relative to 100 parts by mass of the epoxy compound and the unsaturated monobasic acid) as polymerization inhibitors, and 2,4,6-tris(dimethylaminomethyl)phenol ("Seikuol") as an esterification catalyst were added. 8.5 g (0.3 parts by mass per 100 parts by mass of the epoxy compound and unsaturated monobasic acid) of methacrylic acid was added and heated to 100°C. 891 g of methacrylic acid (100 moles per 100 moles of the epoxy group total of the epoxy compound) was added dropwise over 30 minutes, followed by a reaction for 2 hours to obtain vinyl ester resin (b2). The reaction product was cooled to 90°C, and 815 g (20% by mass based on the total amount of the components) of phenoxyethyl methacrylate, an ethylenically unsaturated group-containing monomer (B), was added as a reactive diluent to obtain a mixture of vinyl ester resin (b2) and phenoxyethyl methacrylate (mass ratio 70.0 / 30.0).

[0087]

[0088] [Production of Resin Compositions] Resin compositions 1 to 4 shown in Table 3 were produced using each of the ethylenically unsaturated group-containing resins (A) obtained in the above synthesis examples.

[0089] Production Example 1 To 100 parts by mass of a mixture (adjusted to a mass ratio of 54.9 / 45.1) prepared by dissolving unsaturated polyester resin (a1) in styrene, which is the ethylenically unsaturated group-containing monomer (B), 0.11 parts by mass of phenylbis(2,4,6-trimethylbenzoyl)phosphine oxide (BAPO) and 0.11 parts by mass of 2,2-dimethoxy-2-phenylacetophenone (DMPA) as photopolymerization initiators (C) were added, and the mixture was stirred and mixed at 2000 to 3000 rpm for 10 minutes in a high-speed disperser ("Homodisper 2.5 type," manufactured by Primix Corporation), to produce resin composition 1.

[0090] [Production Examples 2 to 4] Resin compositions 2 to 4 were produced in the same manner as in Production Example 1, except that the raw materials were mixed in the compositions shown in Table 3.

[0091] [Production of Cured Product] Using each of the resin compositions produced in the above Production Examples, a cured product of the resin composition was produced as follows.

[0092] Details of the film (cellophane film) used in the following examples are shown in Table 2. A cellophane film was attached to a glass plate (300 mm long x 300 mm wide x 5 mm thick) and irradiated with a metal halide lamp ("SHL-250", manufactured by Shonan Kosakusho Co., Ltd.), and the absorption and transmission spectra of the light transmitted through the film and the glass plate were measured using a spectroradiometer ("USR-45VA", manufactured by Ushio Inc.). The wavelength ranges of light transmittance of 40% or less in Table 2 were determined in the wavelength range of 400 to 1100 nm, using the transmitted light of the glass plate alone (without film attached) as a reference.

[0093]

[0094] Examples 1 to 8 and Comparative Examples 1 to 8 A mold was prepared by sandwiching a U-shaped NBR rubber spacer (10 mm wide, 4 mm thick) between two glass plates (300 mm long x 300 mm wide x 5 mm thick) along three sides of the plate surfaces and securing them with clips. Each film (cellophane film) shown in Table 3 was attached to both sides of the mold (outside the two glass plates). A resin composition was poured into the gap (inside the mold) between the two glass plates of the prepared mold, and LED light was irradiated onto the mold from the outside of the glass plate surfaces through the film. Note that in Comparative Examples 1 to 3 and 6 to 8, no film was attached. The LED (LED (1)) emitting light (1) and the LED (LED (2)) emitting light (2) each had the maximum emission wavelength shown in Table 3. LED (1) and LED (2) were irradiated from opposite sides of the glass plates of the mold, and when both were irradiated, they were irradiated simultaneously. After 30 minutes of irradiation, the coating was left to stand at room temperature (23°C) for 12 hours for curing, and then removed from the mold to obtain a cured product.

[0095] The irradiance was adjusted by placing a separately prepared glass plate at the position where the mold was to be placed, and adjusting the position and output of the LED irradiator based on the irradiance value measured by directing the transmitted light of the LED light through the glass plate onto the light receiver of a spectroradiometer (USR-45VA, manufactured by Ushio Inc.).

[0096] [Measurement and Evaluation of Cured Product] Each of the produced cured products was measured and evaluated for the following items (measurement environment: temperature 23° C., humidity 50% RH). The evaluation results are shown in Table 3.

[0097] [Head deflection temperature] Measurement was carried out under the following conditions in accordance with JIS K 7191-2:2015 Appendix A. <Measurement conditions> - Apparatus: Head deflection temperature (HTD) tester "S-3M" (manufactured by Toyo Seiki Co., Ltd.) - Test piece dimensions: Width 10 mm x Length 100 mm x Thickness 4 mm - Load: Bending stress 1.80 MPa - Specified deflection amount: 0.34 mm - Heating rate: 120°C / hr The average of the measured values ​​for three test pieces was taken as the head deflection temperature of the cured product.

[0098] [Flexural strength and flexural modulus] Measurements were carried out in accordance with JIS K 7171:2016 under the following conditions. <Measurement conditions> - Apparatus: "Autograph AGS-10kNX" (manufactured by Shimadzu Corporation) - Analysis software: "TRAPEZIUM LITE X" (manufactured by Shimadzu Corporation) - Test piece dimensions: width 10 mm x length 80 mm x thickness 4 mm - Test speed: 1.7 mm / min The average values ​​measured for five test pieces were taken as the flexural strength and flexural modulus of each cured product.

[0099]

[0100] According to the method for producing a cured product of the resin composition of the present embodiment, it has been confirmed that the heat resistance and bending properties of the cured product of a resin composition containing an ethylenically unsaturated group-containing resin (A), an ethylenically unsaturated group-containing monomer (B), and a photopolymerization initiator (C) can be improved by using a colored film and irradiating it with light from an LED.

Claims

1. A method for producing a cured product of a resin composition, comprising: irradiating a resin composition containing an ethylenically unsaturated group-containing resin (A), an ethylenically unsaturated group-containing monomer (B), and a photopolymerization initiator (C) with light emitted from a light-emitting diode through a colored film to cure the resin composition; the colored film has a maximum absorption wavelength in the wavelength range of 400 to 1100 nm; and the light emitted from the light-emitting diode comprises light (1) in the absorption wavelength range of the photopolymerization initiator (C) and light (2) in the absorption wavelength range of the colored film.

2. A method for producing a cured product of the resin composition according to claim 1, wherein the light irradiated to the resin composition includes light in the wavelength range of 400 to 1100 nm and has at least two peak wavelengths.

3. A method for producing a cured product of the resin composition according to claim 1 or 2, wherein the light emitting diode that emits light (1) has a peak wavelength in the wavelength range of 250 to 400 nm.

4. A method for producing a cured product of the resin composition according to claim 1 or 2, wherein the light emitting diode that emits light (2) has a peak wavelength in a wavelength range of 400 to 1100 nm where the light transmittance of the colored film is 40% or less.

5. A method for producing a cured product of the resin composition according to claim 1 or 2, wherein the ethylenically unsaturated group-containing resin (A) is at least one selected from the group consisting of unsaturated polyester resins, vinyl ester resins, (meth)acrylic resins and urethane (meth)acrylate resins.

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