WO2024090084A1

WO2024090084A1 - Resin composition and composite material

Info

Publication number: WO2024090084A1
Application number: PCT/JP2023/034312
Authority: WO
Inventors: 尚人岡田; 健一小林
Original assignee: 株式会社レゾナック
Priority date: 2022-10-28
Filing date: 2023-09-21
Publication date: 2024-05-02

Abstract

Provided are: a resin composition which has high transparency, is excellent in compatibility and curing performance, and hardly causes curing failure, even when an unsaturated polyester resin and a (meth)acryloyloxy group-containing resin are mixed; and a composite material comprising same. This resin composition comprises an unsaturated polyester resin (A), a certain (meth)acryloyloxy group-containing resin (B), an ethylenically unsaturated group-containing monomer (C), a compatibilizing agent (D), and a polymerization initiator (E), the resin composition containing, as the (meth)acryloyloxy group-containing resin (B), a certain vinyl ester resin (B1), wherein the compatibilizing agent (D) is an organic metal compound including at least one selected from metal elements of the groups 1, 12, and 14, and the content of the compatibilizing agent (D) in terms of metal is 800-1,850 ppm by mass based on the total amount of the unsaturated polyester resin (A), (meth)acryloyloxy group-containing resin (B), ethylenically unsaturated group-containing monomer (C), compatibilizing agent (D), and polymerization initiator (E).

Description

Resin composition and composite material

The present invention relates to a resin composition and a composite material.

　Conventionally, a method for repairing existing pipes such as gas pipes, water pipes, sewer pipes, and agricultural water pipes involves using a pipe repair material in which a resin composition is impregnated into a fiber base material. Specifically, the pipe is repaired by installing the pipe repair material at a predetermined position inside the existing pipe and then curing the resin composition contained in the pipe repair material. This method includes a heat curing method that uses a thermosetting resin as the resin composition, and a photocuring method that uses a photocuring resin. In the heat curing method, the resin composition is cured using a heat medium such as hot water or steam. In the photocuring method, the resin composition is cured by irradiating the pipe repair material with light such as ultraviolet light or visible light.

Patent Document 1 describes a thermosetting resin composition for pipe lining material, which contains as essential components an unsaturated polyester resin (a), a polymerizable monomer (b), and a thixotropy imparting agent (c) such as silica powder.
Furthermore, Patent Document 2 describes a resin composition for repairing pipes and culverts, which contains (A) a vinyl ester resin composition, (B) a urethane (meth)acrylate composition, (C) an unsaturated polyester resin composition having an acid value of 90 KOHmg/g or more, and (D) a curing agent containing cumene hydroperoxide and t-butyl peroxybenzoate.
Furthermore, Patent Document 3 describes a tubular photocurable lining material that contains a photocurable resin composition that contains a polymerizable resin such as an unsaturated polyester resin or a vinyl ester resin, an unsaturated polymerizable monomer such as styrene, and a photopolymerization initiator.

In recent years, the length of construction using the light-curing method in repair work on existing pipes has been increasing. This is because the resin composition cures faster and the construction time is shorter than with the heat-curing method. In addition, the light-curing method has the advantages of allowing long-term storage of pipe repair materials, a smaller risk of construction defects due to environmental impacts, and less odor during construction compared to the heat-curing method.

In the photocuring method, gallium lamps, metal halide lamps, mercury lamps, etc. are used as light sources. Patent Document 4 describes a pipe lining method in which a resin layer is irradiated with light from a photocuring device using light-emitting diodes (LEDs) whose main irradiation wavelength is ultraviolet light. LEDs generate little heat, are energy-saving, have a long life, and are excellent as light sources.

JP 2001-62921 A International Publication No. 2015/056585 JP 2013-223939 A JP 2008-142996 A

Unsaturated polyester resins have traditionally been used for pipe rehabilitation, but in recent years, there has been a demand for thinner constituent materials and improved corrosion resistance, heat resistance, and strength properties to ensure the flow capacity of pipelines. These performance properties can be improved by mixing and using resins containing (meth)acryloyloxy groups, but at low temperatures, etc., the resin becomes cloudy due to phase separation, so curing may be insufficient when using photocuring methods, and there are limitations from the standpoint of compatibility.

The present invention has been made in consideration of the above circumstances, and aims to provide a resin composition and a composite material containing the same that are highly transparent, have excellent compatibility and curing properties, and are less likely to cause curing defects, even when an unsaturated polyester resin and a (meth)acryloyloxy group-containing resin are mixed.

As a result of intensive research into solving the above problems, the inventors have discovered that the above problems can be solved by the following invention.

That is, the present invention provides the following means.
[1] A resin composition comprising an unsaturated polyester resin (A), a (meth)acryloyloxy group-containing resin (B), an ethylenically unsaturated group-containing monomer (C), a compatibilizer (D), and a polymerization initiator (E), wherein the (meth)acryloyloxy group-containing resin (B) is a resin having two or more (meth)acryloyloxy groups in one molecule and a weight average molecular weight (Mw) of 500 to 3,000, and the (meth)acryloyloxy group-containing resin (B) contains a vinyl ester resin (B1), and the vinyl ester resin (B1) is an addition product of a raw material containing an epoxy compound (b1-1) and an unsaturated monobasic acid (b1-3). A resin composition which is a reaction product, wherein the epoxy compound (b1-1) contains 30 to 100 mass% of a bisphenol type epoxy resin having an epoxy equivalent of 300 or less, relative to 100 mass% of the epoxy compound (b1-1); the compatibilizer (D) is an organometallic compound containing at least one metal element selected from the group consisting of metal elements of Groups 1, 12, and 14; and the content of the compatibilizer (D) in terms of metal is 800 to 1,850 ppm by mass relative to the total of the unsaturated polyester resin (A), the (meth)acryloyloxy group-containing resin (B), the ethylenically unsaturated group-containing monomer (C), the compatibilizer (D), and the polymerization initiator (E).
[2] The resin composition according to the above [1], wherein the ratio of the weight average molecular weight (Mw) of the unsaturated polyester resin (A) to the weight average molecular weight (Mw) of the (meth)acryloyloxy group-containing resin (B) (weight average molecular weight (Mw) of the unsaturated polyester resin (A) / weight average molecular weight (Mw) of the (meth)acryloyloxy group-containing resin (B)) is 1.5 to 30.
[3] The unsaturated polyester resin (A) is an unsaturated polyester resin obtained by esterification reaction of a diol (a1), an ethylenically unsaturated group-containing dibasic acid (a2-1), and a saturated dibasic acid (a2-2). The resin composition according to [1] or [2] above.
[4] The resin composition according to any one of the above [1] to [3], wherein the content of the unsaturated polyester resin (A) is 25 to 50 mass%, the content of the (meth)acryloyloxy group-containing resin (B) is 12 to 30 mass%, and the content of the ethylenically unsaturated group-containing monomer (C) is 20 to 63 mass%, relative to a total of 100 mass% of the unsaturated polyester resin (A), the (meth)acryloyloxy group-containing resin (B), and the ethylenically unsaturated group-containing monomer (C).
[5] The resin composition according to any one of the above [1] to [4], wherein the metal element of the organometallic compound is at least one selected from zinc, potassium, and tin.
[6] The resin composition according to any one of the above [1] to [5], wherein the organometallic compound is at least one selected from zinc octoate, zinc neodecanoate, potassium octoate, tin octoate, and tin bisacetylacetonate.
[7] The resin composition according to any one of the above [1] to [6], wherein the polymerization initiator (E) is a photopolymerization initiator.
[8] The resin composition according to any one of the above [1] to [7], wherein the content of the polymerization initiator (E) is 0.02 to 10 parts by mass per 100 parts by mass of the total of the unsaturated polyester resin (A), the (meth)acryloyloxy group-containing resin (B), and the ethylenically unsaturated group-containing monomer (C).
[9] The resin composition according to any one of the above [1] to [8], wherein the polymerization initiator (E) is at least one selected from 2,2-dimethoxy-2-phenylacetophenone, diphenyl(2,4,6-trimethylbenzoyl)phosphine oxide, phenylbis(2,4,6-trimethylbenzoyl)phosphine oxide, and 1-hydroxycyclohexyl phenyl ketone.
[10] A composite material comprising the resin composition according to any one of [1] to [9] above, a fiber base material (F), and at least one selected from a filler (G).
[11] The composite material according to the above [10], wherein the fiber base material (F) is at least one selected from glass fibers and polyester fibers.
[12] The composite material according to [10] or [11] above, wherein the filler (G) is at least one selected from aluminum hydroxide and calcium carbonate.
[13] A cured product of the resin composition according to any one of [1] to [9] above or the composite material according to any one of [10] to [12] above.

The present invention provides a resin composition that is highly transparent, has excellent compatibility and curability, and is less prone to curing defects, even when an unsaturated polyester resin (A) and a (meth)acryloyloxy group-containing resin (B) are mixed, and a composite material containing the resin composition.

First, the definitions and meanings of the terms and expressions used in this specification are given below.
"(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" (hereinafter, also simply referred to as "Mw") and the "number average molecular weight Mn" (hereinafter, also simply referred to as "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 "viscosity" of the vinyl ester resin is represented by the viscosity of a mixture of the vinyl ester resin and the ethylenically unsaturated group-containing monomer (C). The viscosity is a value measured at a temperature of 25°C using an E-type viscometer. Specifically, it is measured by the method described in the examples below.

<Resin composition>
The resin composition of the present embodiment contains an unsaturated polyester resin (A), a (meth)acryloyloxy group-containing resin (B), an ethylenically unsaturated group-containing monomer (C), a compatibilizer (D), and a polymerization initiator (E).
In this embodiment, the (meth)acryloyloxy group-containing resin (B) is a resin having two or more (meth)acryloyloxy groups in one molecule and having a weight average molecular weight (Mw) of 500 to 3,000. The (meth)acryloyloxy group-containing resin (B) contains a vinyl ester resin (B1), the vinyl ester resin (B1) is an addition reaction product of raw materials containing an epoxy compound (b1-1) and an unsaturated monobasic acid (b1-3), and the epoxy compound (b1-1) contains 30 to 100 mass% of a bisphenol-type epoxy resin having an epoxy equivalent of 300 or less, relative to 100 mass% of the epoxy compound (b1-1).
In the present embodiment, the compatibilizer (D) is an organometallic compound containing at least one metal element selected from the group 1, group 12, and group 14 metal elements, and the content of the compatibilizer (D) in terms of metal is 800 to 1,850 ppm by mass with respect to the total amount of the unsaturated polyester resin (A), the (meth)acryloyloxy group-containing resin (B), the ethylenically unsaturated group-containing monomer (C), the compatibilizer (D), and the polymerization initiator (E).

The resin composition of this embodiment contains a specific organometallic compound as a compatibilizer (D), which suppresses turbidity caused by the difference in molecular weight between the unsaturated polyester resin (A) and the (meth)acryloyloxy group-containing resin (B) in the resin composition, making it possible to produce a highly transparent resin composition. This resin composition has good light transmittance, so it is believed that irradiated light can easily reach not only the irradiated surface but also the inside, making it less likely to cause poor curing.

[Unsaturated polyester resin (A)]
The unsaturated polyester resin (A) used in this embodiment is obtained by an esterification reaction between a diol (a1) and a dibasic acid (a2).
The unsaturated polyester resin (A) used in the present embodiment is preferably one obtained by an esterification reaction between a diol (a1) and an ethylenically unsaturated group-containing dibasic acid (a2-1) and a saturated dibasic acid (a2-2) described below.
The content ratio (molar ratio) of the structural units derived from the diol (a1) and the structural units derived from the dibasic acid (a2) contained in the unsaturated polyester resin (A) is preferably 40:60 to 60:40, more preferably 45:55 to 55:45, and even more preferably 50:50, from the viewpoints of the curability of the resin composition and the strength properties of the cured resin.

From the viewpoint of suppressing turbidity that occurs when the unsaturated polyester resin (A) and the (meth)acryloyloxy group-containing resin (B) are mixed, the weight average molecular weight (Mw) of the unsaturated polyester resin (A) is preferably 3,000 to 20,000, more preferably 4,000 to 15,000, and even more preferably 5,000 to 12,000.

The number average molecular weight (Mn) of the unsaturated polyester resin (A) is preferably 1,000 to 5,000, more preferably 1,500 to 4,500, and even more preferably 2,000 to 4,000, from the viewpoint of compatibility with the (meth)acryloyloxy group-containing resin (B).

From the viewpoint of ease of control of synthesis conditions, the Mw/Mn of the unsaturated polyester resin (A) is preferably 1.5 to 5.0, more preferably 1.8 to 4.5, and even more preferably 2.1 to 4.0.

In addition, from the viewpoint of suppressing turbidity that occurs when the unsaturated polyester resin (A) and the (meth)acryloyloxy group-containing resin (B) are mixed, the ratio of the weight average molecular weight (Mw) of the unsaturated polyester resin (A) to the weight average molecular weight (Mw) of the (meth)acryloyloxy group-containing resin (B), (Mw of unsaturated polyester resin (A))/Mw of the (meth)acryloyloxy group-containing resin (B), is preferably 1.5 to 30, more preferably 1.75 to 25, and even more preferably 1.8 to 20.

(Diol (a1))
The diol (a1) is a compound having two hydroxyl groups in one molecule. The diol (a1) may be used alone or in combination of two or more kinds.

Examples of the diol (a1) include ethylene glycol, propylene glycol, diethylene glycol, dipropylene 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-ethyl-1,3-hexanediol, 2,5-dimethyl-2,5-hexanol, and the like. Examples of the alkyl ethers include sandiol, 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, as well as hydrogenated products of bisphenol A, bisphenol F, and bisphenol S, dihydric alcohols such as polyethylene glycol and polypropylene glycol, glycerin, trimethylolethane, trimethylolpropane, pentaerythritol, and dipentaerythritol.
Among these, from the viewpoints of production stability of the resin composition, molecular weight control, and strength properties of the cured resin, ethylene glycol, propylene glycol, diethylene glycol, dipropylene glycol, 2-methyl-1,3-propanediol, 2,2-dimethyl-1,3-propanediol, and hydrogenated bisphenol A are preferred, and from the viewpoints of availability and production costs, ethylene glycol, propylene glycol, diethylene glycol, 2-methyl-1,3-propanediol, and 2,2-dimethyl-1,3-propanediol are more preferred.

(Dibasic acid (a2))
The dibasic acid (a2) preferably contains an ethylenically unsaturated group-containing dibasic acid (a2-1) and further contains a saturated dibasic acid (a2-2).

<Ethylenically unsaturated group-containing dibasic acid (a2-1)>
The ethylenically unsaturated group-containing dibasic acid (a2-1) is a compound having two carboxy groups and one or more ethylenically unsaturated groups in one molecule, and its molecular weight and molecular structure are not particularly limited. As the ethylenically unsaturated group-containing dibasic acid (a2-1), a compound having two carboxy groups and one or more ethylenically unsaturated groups in one molecule can be used among the compounds exemplified as the unsaturated polybasic acid (b1-4) described later. The ethylenically unsaturated group-containing dibasic acid (a2-1) may be used alone or in combination of two or more kinds.

Examples of the ethylenically unsaturated group-containing dibasic acid (a2-1) include maleic anhydride, fumaric acid, itaconic acid, citraconic acid, and chloromaleic acid. Among these, from the viewpoint of production costs, maleic anhydride and fumaric acid are preferred, and maleic anhydride is more preferred.

<Saturated dibasic acid (a2-2)>
The saturated dibasic acid (a2-2) is a compound having two carboxy groups and no ethylenically unsaturated group in one molecule, and its molecular weight and molecular structure are not particularly limited. The saturated dibasic acid (a2-2) may be used alone or in combination of two or more kinds.

Examples of the saturated dibasic acid (a2-2) 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, dimethyl orthophthalate, dimethyl isophthalate, dimethyl terephthalate, etc. Among these, phthalic anhydride, isophthalic acid, and terephthalic acid are preferred from the viewpoint of production costs.

[Method for producing unsaturated polyester resin (A)]
The unsaturated polyester resin (A) can be produced by dehydration condensation polymerization of a diol (a1), an ethylenically unsaturated group-containing dibasic acid (a2-1), and a saturated dibasic acid (a2-2).
For example, the copolymer can be produced by reacting the diol (a1), the ethylenically unsaturated group-containing dibasic acid (a2-1) and the saturated dibasic acid (a2-2) in a reaction vessel capable of being heated and stirred at preferably 150 to 250° C., more preferably 170 to 240° C., and even more preferably 180 to 230° C., for 8 to 15 hours.
In this embodiment, from the viewpoint of the curability of the resin composition, it is preferable to react the diol (a1) and the saturated dibasic acid (a2-2) so that the molar ratio (diol (a1):saturated dibasic acid (a2-2)) is 100:80 to 100:20, more preferably 100:70 to 100:30, and even more preferably 100:60 to 100:40.
The timing of mixing the diol (a1), the ethylenically unsaturated group-containing dibasic acid (a2-1), and the saturated dibasic acid (a2-2) is not particularly limited, and they can be mixed by a known method.

The content of the unsaturated polyester resin (A) in the resin composition according to the present embodiment is preferably 25 to 50 mass%, more preferably 27 to 48 mass%, and even more preferably 28 to 46 mass%, relative to 100 mass% in total of the unsaturated polyester resin (A), the (meth)acryloyloxy group-containing resin (B), and the ethylenically unsaturated group-containing monomer (C).
When the content of the unsaturated polyester resin (A) is 25% by mass or more, the toughness of the cured resin is likely to be improved. When the content of the unsaturated polyester resin (A) is 50% by mass or less, the interaction with the compatibilizer (D) is easily controlled.

[(Meth)acryloyloxy group-containing resin (B)]
The (meth)acryloyloxy group-containing resin (B) used in the present embodiment is not particularly limited as long as it has two or more (meth)acryloyloxy groups in one molecule and has a weight average molecular weight (Mw) of 500 to 3,000.
The resin composition of the present embodiment contains a vinyl ester resin (B1) as the (meth)acryloyloxy group-containing resin (B). This allows interaction with the compatibilizer (D) to improve the compatibility between the unsaturated polyester resin (A) and the (meth)acryloyloxy group-containing resin (B), thereby suppressing turbidity of the resin composition.
The (meth)acryloyloxy group-containing resin (B) may be used alone or in combination of two or more kinds.

If the molecular weight of the (meth)acryloyloxy group-containing resin (B) in the resin composition is large, turbidity is likely to occur when mixed with the unsaturated polyester resin (A). From the viewpoint of suppressing turbidity that occurs when the unsaturated polyester resin (A) and the (meth)acryloyloxy group-containing resin (B) are mixed, the weight average molecular weight (Mw) of the (meth)acryloyloxy group-containing resin (B) is 500 to 3,000, preferably 600 to 2,800, and more preferably 800 to 2,500.

The number average molecular weight (Mn) of the (meth)acryloyloxy group-containing resin (B) is preferably 400 to 1,500, more preferably 500 to 1,400, and even more preferably 550 to 1,300, from the viewpoint of compatibility with the unsaturated polyester resin (A).

From the viewpoint of ease of control of synthesis conditions, the Mw/Mn of the (meth)acryloyloxy group-containing resin (B) is preferably 1.1 to 2.5, more preferably 1.2 to 2.4, and even more preferably 1.3 to 2.3.

[Vinyl ester resin (B1)]
In the vinyl ester resin (B1), a hydroxyl group generated by ring-opening of the epoxy group of the epoxy compound (b1-1) and a hydroxyl group of the unsaturated polyester resin (A) interact with the compatibilizer (D), whereby the compatibility between the unsaturated polyester resin (A) and the vinyl ester resin (B1) is improved, and turbidity of the resin composition can be suppressed.

Vinyl ester resin (B1) is an addition reaction product of raw materials including an epoxy compound (b1-1) and an unsaturated monobasic acid (b1-3). Examples of vinyl ester resin (B1) include vinyl ester resin (B1-1) which is an addition reaction product of an epoxy compound (b1-1) having two epoxy groups in one molecule, a bisphenol compound (b1-2), an unsaturated monobasic acid (b1-3), and a polybasic acid anhydride (b1-4), and vinyl ester resin (B1-2) which is an addition reaction product of an epoxy compound (b1-1) having two epoxy groups in one molecule, and an unsaturated monobasic acid (b1-3). These resins may be used alone or in combination of two or more.

[Vinyl ester resin (B1-1)]
The vinyl ester resin (B1-1) is an addition reaction product obtained by reacting a resin precursor (P1), which is a reaction product of an epoxy compound (b1-1) having two epoxy groups in one molecule and a bisphenol compound (b1-2), with an unsaturated monobasic acid (b1-3) and an unsaturated polybasic acid (b1-4).

The amount of bisphenol compound (b1-2) in the raw material of vinyl ester resin (B1-1) is preferably such that the total amount of hydroxyl groups in bisphenol compound (b1-2) is 10 moles or more, more preferably 15 moles or more, even more preferably 20 moles or more, per 100 moles of the total amount of epoxy groups in epoxy compound (b1-1), and is preferably 70 moles or less, more preferably 50 moles or less, even more preferably 30 moles or less.

If the total amount of hydroxyl groups in the bisphenol compound (b1-2) is 10 moles or more relative to 100 moles of the total amount of epoxy groups in the epoxy compound (b1-1), the molecular weight distribution of the vinyl ester resin (B1-1) will be broadened, making it easier to make it compatible with the unsaturated polyester resin (A), and it will be possible to achieve both toughness and toughness of the resin cured product. In addition, if the total amount of hydroxyl groups in the bisphenol compound (b1-2) is 70 moles or less relative to 100 moles of the total amount of epoxy groups in the epoxy compound (b1-1), the molecular weight of the resin composition will be prevented from becoming excessively large, and it will be easier to control the viscosity of the resin composition.

The amount of unsaturated monobasic acid (b1-3) in the raw material of vinyl ester resin (B1-1) is preferably such that the total amount of acid groups of unsaturated monobasic acid (b1-3) is 40 moles or more, more preferably 50 moles or more, even more preferably 60 moles or more, and is preferably 120 moles or less, more preferably 100 moles or less, even more preferably 80 moles or less, per 100 moles of the total amount of epoxy groups of epoxy compound (b1-1).

If the total amount of acid groups in the unsaturated monobasic acid (b1-3) is 40 moles or more relative to 100 moles of the total amount of epoxy groups in the epoxy compound (b1-1), a sufficient amount of ethylenically unsaturated groups is introduced into the vinyl ester resin (B1-1), and the resin composition is likely to exhibit good curing properties. In addition, if the total amount of acid groups in the unsaturated monobasic acid (b1-3) is 120 moles or less relative to 100 moles of the total amount of epoxy groups in the epoxy compound (b1-1), compatibility with the unsaturated polyester resin (A) is good.

The amount of unsaturated polybasic acid (b1-4) in the raw material of vinyl ester resin (B1-1) is preferably such that the total amount of acid groups of unsaturated polybasic acid (b1-4) is 1 mole or more, more preferably 3 moles or more, even more preferably 5 moles or more, and is preferably 15 moles or less, more preferably 10 moles or less, even more preferably 8 moles or less, per 100 moles of the total amount of epoxy groups of epoxy compound (b1-1).

If the total amount of acid groups in the unsaturated polybasic acid (b1-4) is 1 mole or more per 100 moles of epoxy groups in the epoxy compound (b1-1), a sufficient amount of ethylenically unsaturated groups is introduced into the vinyl ester resin (B1-1), and the resin composition is likely to exhibit good curing properties. In addition, if the total amount of acid groups in the unsaturated polybasic acid (b1-4) is 15 moles or less per 100 moles of epoxy groups in the epoxy compound (b1-1), compatibility with the unsaturated polyester resin (A) will be good.

[Vinyl ester resin (B1-2)]
The vinyl ester resin (B1-2) is an addition reaction product of an epoxy compound (b1-1) having two epoxy groups in one molecule and an unsaturated monobasic acid (b1-3).

The amount of unsaturated monobasic acid (b1-3) in the raw material of vinyl ester resin (B1-2) is preferably such that the total amount of acid groups of unsaturated monobasic acid (b1-3) is 30 moles or more, more preferably 40 moles or more, even more preferably 50 moles or more, and is preferably 120 moles or less, more preferably 110 moles or less, even more preferably 100 moles or less, per 100 moles of the total amount of epoxy groups of epoxy compound (b1-1).

If the total amount of acid groups in the unsaturated monobasic acid (b1-3) is 30 moles or more relative to 100 moles of the total amount of epoxy groups in the epoxy compound (b1-1), a sufficient amount of ethylenically unsaturated groups is introduced into the vinyl ester resin (B1-2), and the resin composition is likely to exhibit good curing properties. In addition, if the total amount of acid groups in the unsaturated monobasic acid (b1-3) is 120 moles or less relative to 100 moles of the total amount of epoxy groups in the epoxy compound (b1-1), compatibility with the unsaturated polyester resin (A) is good.

(Epoxy compound (b1-1))
The epoxy compound (b1-1) is a compound having two epoxy groups in one molecule, and may be a monomer, oligomer, or polymer in general, and its molecular weight and molecular structure are not particularly limited. The epoxy compound (b1-1) may be used alone or in combination of two or more kinds.
In this embodiment, the epoxy compound (b1-1) contains 30 to 100% by mass of a bisphenol type epoxy resin having an epoxy equivalent of 300 or less, relative to 100% by mass of the epoxy compound (b1-1). If the content of the bisphenol type epoxy resin having an epoxy equivalent of 300 or less, relative to 100% by mass of the epoxy compound (b1-1), is 30% by mass or more, the viscosity of the resin composition and the toughness of the cured resin will be good, and if it is 100% by mass or less, the toughness of the cured resin and the compatibility with the unsaturated polyester resin (A) will be good.

Examples of bisphenol type epoxy resins include bisphenol A type epoxy resins, bisphenol F type epoxy resins, bisphenol S type epoxy resins, and bisphenol AF type epoxy resins. Among these, from the viewpoints of corrosion resistance, versatility, and cost, bisphenol A type epoxy resins, bisphenol F type epoxy resins, and bisphenol S type epoxy resins are preferred, and bisphenol A type epoxy resins are more preferred.

Examples of epoxy compounds other than bisphenol-type epoxy resins include t-butylcatechol-type epoxy resins, naphthalene-type epoxy resins, naphthol-type epoxy resins, anthracene-type epoxy resins, glycidyl ester-type epoxy resins, biphenyl-type epoxy resins, linear aliphatic epoxy resins, epoxy resins having a butadiene structure, alicyclic epoxy resins, heterocyclic epoxy resins, spiro ring-containing epoxy resins, cyclohexanedimethanol-type epoxy resins, naphthylene ether-type epoxy resins, and phenol novolac-type epoxy resins. Among these, phenol novolac-type epoxy resins are preferred from the standpoints of corrosion resistance, versatility, and cost.

The epoxy equivalent of the epoxy compound (b1-1) is preferably 100 to 300, more preferably 110 to 280, even more preferably 120 to 270, and even more preferably 150 to 250, from the viewpoints of ease of synthesis and molecular weight control of the resin composition.

(Bisphenol compound (b1-2))
The molecular weight and molecular structure of the bisphenol compound (b1-2) are not particularly limited. The bisphenol compound (b1-2) may be used alone or in combination of two or more kinds.
Examples of the bisphenol compound (b1-2) 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, bisphenol A and bisphenol F are preferred from the viewpoint of ease of synthesis, and bisphenol A is more preferred from the viewpoints of corrosion resistance, versatility, and cost.

(Unsaturated monobasic acid (b1-3))
The unsaturated monobasic acid (b1-3) is not particularly limited in its molecular weight and molecular structure, but is preferably a monocarboxylic acid having an ethylenically unsaturated group. The unsaturated monobasic acid (b1-3) may be used alone or in combination of two or more kinds.

Examples of the unsaturated monobasic acid (b1-3) include (meth)acrylic acid, crotonic acid, cinnamic acid, etc. Among these, from the viewpoints of versatility, reactivity during synthesis of the vinyl ester resins (B1-1) and (B1-2), and obtaining a resin composition having good curability, at least one selected from (meth)acrylic acid and crotonic acid is preferred, (meth)acrylic acid is more preferred, and methacrylic acid is even more preferred.

(Unsaturated polybasic acid (b1-4))
The unsaturated polybasic acid (b1-4) is a compound having two or more carboxy groups and one or more unsaturated groups in one molecule, and its molecular weight and molecular structure are not particularly limited. The unsaturated polybasic acid (b1-4) may be used alone or in combination of two or more kinds.

Examples of the unsaturated polybasic acid (b1-4) 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 viewpoint of production costs, maleic anhydride, fumaric acid, succinic acid, glutaric acid, and adipic acid are preferred, maleic anhydride, fumaric acid, and succinic acid are more preferred, and fumaric acid is even more preferred.

[Method for producing vinyl ester resin (B1)]
[Method for producing vinyl ester resin (B1-1)]
The method for producing the vinyl ester resin (B1-1) includes a step of reacting an epoxy compound (b1-1) having two epoxy groups in one molecule with a bisphenol compound (b1-2) to obtain a resin precursor (P1), and a step of reacting the resin precursor (P1) obtained in the above step with an unsaturated monobasic acid (b1-3) and an unsaturated polybasic acid (b1-4) to obtain the vinyl ester resin (B1-1).

(Step of Obtaining Resin Precursor (P1))
This step is a step of obtaining a resin precursor (P1) by reacting an epoxy compound (b1-1) having two epoxy groups in one molecule with a bisphenol compound (b1-2).
In this step, from the viewpoint of easily achieving compatibility with the unsaturated polyester resin (A) and also achieving toughness of a resin cured product, it is preferable to react an epoxy compound (b1-1) having two epoxy groups in one molecule with a bisphenol compound (b1-2) such that the total amount of hydroxyl groups in the bisphenol compound (b1-2) is preferably 10 to 70 mol, more preferably 15 to 50 mol, and even more preferably 20 to 30 mol, relative to 100 mol of the total amount of epoxy groups in the epoxy compound (b1-1).

In the process of obtaining the resin precursor (P1), for example, the epoxy compound (b1-1) and the bisphenol compound (b1-2) are mixed with at least one of a solvent and a reactive diluent as necessary in a reaction vessel capable of being heated and stirred, and the mixture is heated in the presence of an esterification catalyst at preferably 70 to 160°C, more preferably 80 to 155°C, and even more preferably 90 to 150°C for 1 to 3 hours while being mixed to obtain the resin precursor (P1).

Esterification catalysts include, for example, tertiary amines such as triethylamine, triethylenediamine, N,N-dimethylbenzylamine, N,N-dimethylaniline, 2,4,6-tris(dimethylaminomethyl)phenol, and diazabicyclooctane; phosphorus compounds such as triphenylphosphine and benzyltriphenylphosphonium chloride; or diethylamine hydrochloride, trimethylbenzylammonium chloride, lithium chloride, and the like. These may be used alone or in combination of two or more. Among these, from the viewpoints of slowing down the reaction rate to prevent gelation of the resin and facilitating control of the molecular weight distribution, tertiary amines and phosphorus compounds are preferred, and tertiary amines are more preferred.

The amount of the esterification catalyst used is preferably 0.01 to 5 parts by mass, more preferably 0.05 to 4 parts by mass, and even more preferably 0.1 to 3 parts by mass, per 100 parts by mass of the epoxy compound (b1-1) and the bisphenol compound (b1-2) combined, from the viewpoint of promoting the reaction while suppressing thickening of the vinyl ester resin (B1-1).

The solvent and the reactive diluent are used as necessary from the viewpoint of facilitating uniform mixing of the epoxy compound (b1-1), the bisphenol compound (b1-2), the unsaturated monobasic acid (b1-3), and the unsaturated polybasic acid (b1-4). The mixing method is not particularly limited, and may be performed by a known method.
The solvent is not particularly limited as long as it is inactive to the epoxy compound (b1-1), the bisphenol compound (b1-2), the unsaturated monobasic acid (b1-3), and the unsaturated polybasic acid (b1-4). For example, a known solvent having a boiling point of 70 to 150° C. at 1 atmospheric pressure, such as methyl isobutyl ketone, may be used. The solvent may be used alone or in combination of two or more.
The reactive diluent is preferably an ethylenically unsaturated group-containing monomer (C) which is inactive to the epoxy compound (b1-1), the bisphenol compound (b1-2), the unsaturated monobasic acid (b1-3), and the unsaturated polybasic acid (b1-4).

A polymerization inhibitor may be added from the viewpoint of suppressing the progress of the polymerization reaction of the resin precursor (P1). As the polymerization inhibitor, a known one may be used, and examples thereof include hydroquinone, methylhydroquinone, trimethylhydroquinone, phenothiazine, catechol, 4-t-butylcatechol, copper naphthenate, etc. These may be used alone or in combination of two or more kinds.
The amount of the polymerization inhibitor added, when added, can be, for example, 0.0001 to 10 parts by mass, and preferably 0.001 to 1 part by mass, per 100 parts by mass in total of the epoxy compound (b1-1), the bisphenol compound (b1-2), and the unsaturated monobasic acid (b1-3).

(Step of Obtaining Vinyl Ester Resin (B1-1))
This step is a step of reacting the resin precursor (P1) obtained in the previous step with an unsaturated monobasic acid (b1-3) and an unsaturated polybasic acid (b1-4) to obtain a vinyl ester resin (B1-1).
From the viewpoint of compatibility with the unsaturated polyester resin (A), in this step, it is preferable to react the resin precursor (P1) with the unsaturated monobasic acid (b1-3) and the unsaturated polybasic acid (b1-4) so that the total amount of acid groups in the unsaturated monobasic acid (b1-3) is preferably 40 to 120 mol, more preferably 50 to 100 mol, and even more preferably 60 to 80 mol, and the total amount of acid groups in the unsaturated polybasic acid (b1-4) is preferably 1 to 15 mol, more preferably 3 to 10 mol, and even more preferably 5 to 8 mol, relative to 100 mol of the total amount of epoxy groups in the epoxy compound (b1-1).

In the process for obtaining the vinyl ester resin (B1-1), for example, an unsaturated monobasic acid (b1-3) and an unsaturated polybasic acid (b1-4) are added in the presence of an esterification catalyst to a reaction vessel in which the resin precursor (P1) has been synthesized, and the mixture is heated with mixing at preferably 70 to 150°C, more preferably 80 to 140°C, and even more preferably 90 to 130°C for 30 minutes to 4 hours to produce the vinyl ester resin (B1-1).

The esterification catalyst used in the step of obtaining the vinyl ester resin (B1-1) may be the same as the esterification catalyst used in the step of obtaining the resin precursor (P1) of the vinyl ester resin (B1-1). The esterification catalyst used in this step may be the same as or different from the esterification catalyst used in producing the resin precursor (P1).
In the case where an esterification catalyst is further added in this step, the amount of the catalyst used is, from the viewpoint of promoting the reaction while suppressing thickening of the vinyl ester resin (B1-1), preferably 0.01 to 5 parts by mass, more preferably 0.05 to 4 parts by mass, and even more preferably 0.1 to 3 parts by mass, relative to 100 parts by mass in total of the epoxy compound (b1-1), the bisphenol compound (b1-2), the unsaturated monobasic acid (b1-3), and the unsaturated polybasic acid (b1-4).

In the process of obtaining the vinyl ester resin (B1-1), as in the process of obtaining the resin precursor (P1), at least one of a solvent, a reactive diluent, and a polymerization inhibitor may be added as necessary. As in the process of obtaining the resin precursor (P1), the mixing method may be a known method. The same applies to the preferred embodiments.

[Production method of vinyl ester resin (B1-2)]
The method for producing the vinyl ester resin (B1-2) includes a step of reacting an epoxy compound (b1-1) having two epoxy groups in one molecule with an unsaturated monobasic acid (b1-3) to obtain the vinyl ester resin (B1-2).

(Step of Obtaining Vinyl Ester Resin (B1-2))
This step is a step in which an epoxy compound (b1-1) having two epoxy groups in one molecule and an unsaturated monobasic acid (b1-3) are reacted to obtain a vinyl ester resin (B1-2).
In this step, from the viewpoint of compatibility with the unsaturated polyester resin (A), it is preferable to react an epoxy compound (b1-1) having two epoxy groups in one molecule with an unsaturated monobasic acid (b1-3) such that the total amount of acid groups in the unsaturated monobasic acid (b1-3) is preferably 30 to 120 mol, more preferably 40 to 110 mol, and even more preferably 50 to 100 mol, relative to 100 mol of the total amount of epoxy groups in the epoxy compound (b1-1).

In this process, for example, the epoxy compound (b1-1) and the unsaturated monobasic acid (b1-3) are mixed with at least one of a solvent and a reactive diluent, if necessary, in a reaction vessel capable of being heated and stirred, and the mixture is heated in the presence of an esterification catalyst at preferably 70 to 160°C, more preferably 80 to 150°C, and even more preferably 90 to 120°C, for 1 to 3 hours while being mixed to obtain the vinyl ester resin (B1-2).

The esterification catalyst used in the step of obtaining the vinyl ester resin (B1-2) may be the same as the esterification catalyst used in the step of obtaining the resin precursor (P1) of the vinyl ester resin (B1-1). The esterification catalyst used in this step may be the same as or different from the esterification catalyst used in producing the resin precursor (P1).
The amount of the esterification catalyst used is preferably 0.01 to 5 parts by mass, more preferably 0.05 to 4 parts by mass, and even more preferably 0.1 to 3 parts by mass, per 100 parts by mass of the epoxy compound (b1-1) and the unsaturated monobasic acid (b1-3) in total, from the viewpoint of promoting the reaction while suppressing thickening of the vinyl ester resin (B1-2).

When a reactive diluent is added to the vinyl ester resin (B1) for the purpose of lowering the viscosity of the vinyl ester resin (B1), it is preferable to add and mix the reactive diluent after the synthesis of the vinyl ester resin (B1); when a reactive diluent is added for the purpose of facilitating the synthesis of the vinyl ester resin (B1), it is preferable to add the reactive diluent during the synthesis of the vinyl ester resin (B1), and further add and mix the reactive diluent after the synthesis of the vinyl ester resin (B1).

From the viewpoint of ease of handling, the viscosity of the vinyl ester resin (B1) at 25°C is preferably 0.1 to 1.2 Pa·s, more preferably 0.1 to 1.0 Pa·s, and even more preferably 0.2 to 0.8 Pa·s.

[Other (meth)acryloyloxy group-containing resins]
The resin composition in the present embodiment may contain another (meth)acryloyloxy group-containing resin different from the vinyl ester resin (B1) from the viewpoint of improving the performance such as corrosion resistance, heat resistance, and strength properties of the cured resin.
Examples of the other resins include urethane (meth)acrylate resins, polyester (meth)acrylate resins, (meth)acrylate resins, etc. These other resins may be used alone or in combination of two or more.

The urethane (meth)acrylate resin is a polyurethane having a (meth)acryloyloxy group. Specifically, it is possible to use a radically polymerizable unsaturated group-containing oligomer 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 polyester (meth)acrylate resin is a polyester having a (meth)acryloyloxy group. The polyester (meth)acrylate resin can be obtained, for example, by the following method (1) or (2).
(1) A method of reacting a polyester having a carboxy group at its terminal with an epoxy group-containing (meth)acrylate or a hydroxyl group-containing (meth)acrylate. (2) A method of reacting a polyester having a hydroxyl group at its terminal with (meth)acrylic acid or an isocyanato group-containing (meth)acrylate. The polyester having a carboxy group at its terminal, which is used as a raw material in the above method (1), can be obtained by reacting an excess amount of at least one of a saturated polybasic acid and an unsaturated polybasic acid with a polyhydric alcohol.
The polyester having a hydroxyl group at its terminal, which is used as a raw material in the above method (2), may be one obtained by reacting at least one of a saturated polybasic acid and an unsaturated polybasic acid with an excess amount of a polyhydric alcohol.

(Meth)acrylate resin is a general term for acrylate resin and methacrylate resin, and examples of such resins include homopolymers of alkyl acrylates such as ethyl acrylate, methyl acrylate, and butyl acrylate, and alkyl methacrylates such as ethyl methacrylate, methyl methacrylate, n-butyl methacrylate, i-butyl methacrylate, and t-butyl methacrylate, as well as copolymers with other copolymerizable monomers.

When the (meth)acryloyloxy group-containing resin (B) contains the above-mentioned other (meth)acryloyloxy group-containing resins, the content is preferably less than 30 mass%, more preferably 20 mass% or less, and even more preferably 10 mass% or less, from the viewpoint of improving the performance of the cured resin, such as corrosion resistance, heat resistance, and strength properties.

The content of the (meth)acryloyloxy group-containing resin (B) in the resin composition according to the present embodiment is preferably 12 to 30 mass%, more preferably 13 to 29 mass%, and even more preferably 14 to 28 mass%, relative to 100 mass% in total of the unsaturated polyester resin (A), the (meth)acryloyloxy group-containing resin (B), and the ethylenically unsaturated group-containing monomer (C).
When the content of the (meth)acryloyloxy group-containing resin (B) is 12% by mass or more, the performance of the resin cured product is likely to be improved in terms of corrosion resistance, heat resistance, strength, etc. When the content of the (meth)acryloyloxy group-containing resin (B) is 30% by mass or less, the interaction with the compatibilizer (D) is easily controlled.

[Ethylenically unsaturated group-containing monomer (C)]
The ethylenically unsaturated group-containing monomer (C) used in this embodiment is not particularly limited as long as it is a monomer of a compound having an ethylenically unsaturated group, but it is preferable that it has a vinyl group, an allyl group, a (meth)acryloyl group, etc. However, the (meth)acryloyloxy group-containing resin (B) is excluded. The ethylenically unsaturated group-containing monomer (C) may be used alone or in combination of two or more kinds.
The higher the content of the ethylenically unsaturated group-containing monomer (C), the lower the viscosity of the resin composition can be, and the harder, stronger, more resistant to chemicals, more resistant to water, etc., the cured product of the resin composition can be.

Among the ethylenically unsaturated group-containing monomers (C), those having a (meth)acryloyl group include, for example, (meth)acrylic acid and (meth)acrylate. The (meth)acrylate may be monofunctional or polyfunctional.

Examples of monofunctional (meth)acrylates include methyl (meth)acrylate, ethyl (meth)acrylate, n-butyl (meth)acrylate, i-butyl (meth)acrylate, t-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, dicyclopentenyloxyethyl (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. Examples of such acrylates include silyl ether (meth)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 hydroxyethyl (meth)acrylate, and allyl (meth)acrylate.

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. Polyoxyalkylene glycol di(meth)acrylates such 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, tris-(2-(meth)acryloxyethyl)isocyanurate, etc.

Among the ethylenically unsaturated group-containing monomers (C), those other than (meth)acrylates that have a (meth)acryloyl group include acryloylmorpholine, 2-hydroxyethyl (meth)acrylamide, 2-hydroxyethyl-N-methyl (meth)acrylamide, 3-hydroxypropyl (meth)acrylamide, etc.

Ethylenically unsaturated group-containing monomers (C) that have a vinyl group include, for example, styrene, p-chlorostyrene, vinyltoluene, α-methylstyrene, dichlorostyrene, divinylbenzene, t-butylstyrene, vinyl acetate, diallyl fumarate, diallyl phthalate, triallyl isocyanurate, and vinylbenzyl compounds such as vinylbenzyl butyl ether, vinylbenzyl hexyl ether, and divinylbenzyl ether.

Among these, from the viewpoints of the curability of the resin composition and the manufacturing costs, styrene compounds and (meth)acrylates are preferred. More specifically, at least one selected from 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 is preferred, and styrene is more preferred.

The content of the ethylenically unsaturated group-containing monomer (C) in the resin composition according to the present embodiment is preferably 20 to 63 mass%, more preferably 25 to 60 mass%, and even more preferably 30 to 55 mass%, relative to 100 mass% in total of the unsaturated polyester resin (A), the (meth)acryloyloxy group-containing resin (B), and the ethylenically unsaturated group-containing monomer (C).
When the content of the ethylenically unsaturated group-containing monomer (C) is 20% by mass or more, the viscosity of the resin composition can be easily reduced, and the workability is improved.When the content of the ethylenically unsaturated group-containing monomer (C) is 63% by mass or less, the corrosion resistance, heat resistance, strength properties, etc. of the cured resin are improved.

[Compatibilizer (D)]
The compatibilizer (D) used in this embodiment is an organometallic compound containing at least one metal element selected from the group 1, group 12, and group 14. The compatibilizer (D) has the effect of increasing the compatibility between the unsaturated polyester resin (A) and the (meth)acryloyloxy group-containing resin (B) by interacting with the hydroxyl group in the unsaturated polyester resin (A) and the carboxyl group and hydroxyl group in the (meth)acryloyloxy group-containing resin (B).
The compatibilizer (D) may be used alone or in combination of two or more kinds.

Metal elements in Group 1 include lithium, sodium, and potassium.
Group 12 metal elements include zinc.
Examples of metal elements in Group 14 include tin and lead.

As the compatibilizer (D), from the viewpoint of not inhibiting the photocurability of the resin composition, an organometallic compound containing at least one selected from zinc, potassium, and tin is preferable, zinc octoate, zinc neodecanoate, potassium octoate, tin octoate, and tin bisacetylacetonate are more preferable, and zinc octoate and potassium octoate are even more preferable.

The content of the compatibilizer (D) in the resin composition according to the present embodiment, calculated as metal, is 800 to 1,850 ppm by mass, preferably 850 to 1,700 ppm by mass, and more preferably 900 to 1,500 ppm by mass, based on the total content of the unsaturated polyester resin (A), the (meth)acryloyloxy group-containing resin (B), the ethylenically unsaturated group-containing monomer (C), the compatibilizer (D), and the polymerization initiator (E).
When the content of the compatibilizer (D) in terms of metal is 800 ppm by mass or more, the compatibility between the unsaturated polyester resin (A) and the (meth)acryloyloxy group-containing resin (B) is likely to be improved. When the content of the compatibilizer (D) in terms of metal is 1,850 ppm by mass or less, compatibility and photocurability can be achieved at the same time.

[Polymerization initiator (E)]
The polymerization initiator (E) used in this embodiment may be either a photopolymerization initiator or a thermal polymerization initiator.
The present inventors have found that a cured product with good curability can be obtained by irradiating the resin composition according to this embodiment with only light having a peak half width of 4 to 35 nm and a central wavelength of 315 to 460 nm, which does not include high-energy ultraviolet light having a wavelength of 200 to 314 nm. Therefore, from the viewpoint of exerting the effects of the present invention, the polymerization initiator (E) is preferably a photopolymerization initiator.

When a photopolymerization initiator is used as the polymerization initiator (E), the content of the photopolymerization initiator in the resin composition is preferably 0.02 to 10 parts by mass, more preferably 0.03 to 5 parts by mass, and even more preferably 0.05 to 1 part by mass, relative to a total of 100 parts by mass of the unsaturated polyester resin (A), the (meth)acryloyloxy group-containing resin (B), and the ethylenically unsaturated group-containing monomer (C).
If the content of the photopolymerization initiator is 0.02 parts by mass or more, a resin composition with better curability can be obtained. If the content of the photopolymerization initiator is 10 parts by mass or less, a rapid curing reaction and heat generation are unlikely to occur during curing of the resin composition, and cracks are likely to be suppressed. In addition, a cured product with excellent balance of physical properties such as strength, toughness, heat resistance, and chemical resistance is likely to be obtained.

When a thermal polymerization initiator is used as the polymerization initiator (E), the content of the thermal polymerization initiator in the resin composition is preferably 0.3 to 6.0 parts by mass, more preferably 0.4 to 5.0 parts by mass, and even more preferably 0.5 to 4.0 parts by mass, relative to a total of 100 parts by mass of the unsaturated polyester resin (A), the (meth)acryloyloxy group-containing resin (B), and the ethylenically unsaturated group-containing monomer (C).
When the content of the thermal polymerization initiator is 0.3 parts by mass or more, curability without curing defects can be obtained, and when the content of the thermal polymerization initiator is 6.0 parts by mass or less, a cured product having good physical properties can be obtained.

The photopolymerization initiator is not particularly limited as long as it generates radicals upon irradiation with light. For example, 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-t-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-amyl anthraquinone, 2-t-butyl anthraquinone, and 1-chloro anthraquinone; thioxanthones, such as 2,4-dimethylthioxanthone, 2,4-diisopropylthioxanthone, and 2-chlorothioxanthone; acetophenone dimethyl thioxanthone; Ketals such as tyl ketal and benzyl dimethyl ketal; benzophenones such as benzophenone, 4-(1-t-butyldioxy-1-methylethyl)benzophenone, and 3,3',4,4'-tetrakis(t-butyldioxycarbonyl)benzophenone; morpholines such as 2-methyl-1-[4-(methylthio)phenyl]-2-morpholino-propan-1-one, 2-benzyl-2-dimethylamino-1-(4-morpholinophenyl)butanon-1-one, and 2-benzyl-2-dimethylamino-1-(4-morpholinophenyl)butan-1-one; acylphosphine oxides such as diphenyl(2,4,6-trimethylbenzoyl)phosphine oxide and phenylbis(2,4,6-trimethylbenzoyl)phosphine oxide; and xanthones. These may be used alone or in combination of two or more.

From the viewpoint of reactivity, it is preferable to use an intramolecular cleavage type photopolymerization initiator that does not require a hydrogen donor. In addition, since it absorbs light with a wavelength of 315 to 460 nm to generate active species, it is preferable to use at least one selected from 2,2-dimethoxy-2-phenylacetophenone, diphenyl(2,4,6-trimethylbenzoyl)phosphine oxide, phenylbis(2,4,6-trimethylbenzoyl)phosphine oxide, and 1-hydroxycyclohexyl phenyl ketone, which efficiently generate active species in the above wavelength range, and 2,2-dimethoxy-2-phenylacetophenone and phenylbis(2,4,6-trimethylbenzoyl)phosphine oxide are more preferable.

The thermal polymerization initiator is not particularly limited, and a known radical polymerization initiator can be used. Examples of the thermal polymerization initiator include organic peroxides, azo compounds, persulfates, redox compounds, etc. Among these, organic peroxides are preferred.
Examples of organic peroxides include ketone peroxides, perbenzoates, hydroperoxides, diacyl peroxides, peroxyketals, hydroperoxides, diallyl peroxides, peroxy esters, and peroxydicarbonates. More specific examples include methyl ethyl ketone peroxide, cumene hydroperoxide, t-butyl perbenzoate, 1,1,3,3-tetramethylbutyl 2-ethylhexaneperoxy acid, dibenzoyl peroxide (also called benzoyl peroxide), benzoyl m-methylbenzoyl peroxide, m-toluoyl peroxide, dicumyl peroxide, diisopropyl peroxide, di-t-butyl peroxide, t-butyl peroxybenzoate, 1,1-bis(t-butyl Examples of the peroxy group include 2,5-dimethyl-2,5-bis(t-butylperoxy)hexyne-3,3-isopropyl hydroperoxide, t-butyl hydroperoxide, dicumyl hydroperoxide, acetyl peroxide, bis(4-t-butylcyclohexyl)peroxydicarbonate, diisopropyl peroxydicarbonate, isobutyl peroxide, 3,3,5-trimethylhexanoyl peroxide, and lauryl peroxide. These may be used alone or in combination of two or more.

Among these, from the standpoint of ease of curing control, availability, ease of handling, etc., bis(4-t-butylcyclohexyl) peroxydicarbonate, 1,1,3,3-tetramethylbutyl 2-ethylhexaneperoxy acid, dibenzoyl peroxide, benzoyl m-methylbenzoyl peroxide, m-toluoyl peroxide, methyl ethyl ketone peroxide, and t-butyl peroxybenzoate are preferred.

[Other ingredients]
The resin composition of the present embodiment may contain, as other components, additives such as, for example, resins other than the unsaturated polyester resin (A), the (meth)acryloyloxy group-containing resin (B), and the ethylenically unsaturated group-containing monomer (C), polymerization inhibitors, thixotropic agents, curing accelerators, catalysts, thickening aids, curing retarders, surfactants, interface regulators, wetting and dispersing agents, defoamers, leveling agents, coupling agents, light stabilizers, waxes, flame retardants, and plasticizers. The content of the additives is not particularly limited as long as it is within a range that does not impair the effects of the present invention.

The resin composition of this embodiment preferably contains a polymerization inhibitor from the viewpoint of suppressing the progress of the polymerization reaction of the resin composition. The polymerization inhibitor that is preferably used is the one described above in the section [Production method of vinyl ester resin (B1)].

[Physical Properties of Resin Composition]
The resin composition of the present embodiment has a haze of preferably less than 70%, more preferably less than 50%, and even more preferably less than 35%.
The resin composition of the present embodiment has a total light transmittance of preferably 70% or more, more preferably 75% or more, and even more preferably 79% or more.
The cured product of the resin composition of this embodiment preferably has a Barcol hardness of 16 or more, more preferably 18 or more, and even more preferably 21 or more.
The above haze, total light transmittance, and Barcol hardness can all be measured by the method described in the Examples.

The resin composition of this embodiment, even when mixed with the unsaturated polyester resin (A) and the (meth)acryloyloxy group-containing resin (B), has high transparency, excellent compatibility and curing properties, and is less likely to cause curing defects, so it can be preferably used as a material for pipe repair materials, in particular as a material for pipe repair materials that have good curing properties when cured with LED.

<Method for producing resin composition>
The method for preparing the resin composition of this embodiment is not particularly limited, but the resin composition can be produced by mixing the unsaturated polyester resin (A), the (meth)acryloyloxy group-containing resin (B), the ethylenically unsaturated group-containing monomer (C), the compatibilizer (D), and the polymerization initiator (E). In addition, the unsaturated polyester resin (A), the (meth)acryloyloxy group-containing resin (B), the ethylenically unsaturated group-containing monomer (C), the compatibilizer (D), the polymerization initiator (E), and any other optional components such as the other components may be mixed.

The mixing order is not particularly limited. The mixing method is not particularly limited, and can be performed using, for example, a disperser, a planetary mixer, a kneader, etc. The mixing temperature is preferably 10 to 50°C, more preferably 15 to 40°C, and from the viewpoint of ease of mixing, etc., is even more preferably 20 to 30°C.

In addition, from the viewpoint of facilitating uniform mixing of the unsaturated polyester resin (A), the (meth)acryloyloxy group-containing resin (B), the ethylenically unsaturated group-containing monomer (C), the compatibilizer (D), and the polymerization initiator (E), the (meth)acryloyloxy group-containing resin (B) may be diluted in advance with at least one of a solvent and a reactive diluent.

<Composite materials>
The composite material of the present embodiment contains the above-mentioned resin composition and at least one selected from a fiber base material (F) and a filler (G).
A preferred composite material is, for example, a material obtained by impregnating a fiber substrate (F) with the resin composition and storing (curing) it for a certain period of time to thicken it. Such a composite material has good shape retention, and a cured product (molded product) having excellent mechanical strength as a lining material for pipe rehabilitation can be obtained.

The composite material containing the above resin composition and the fiber base material (F) can be used for application to structures as materials such as preforms, prepregs, and lining materials for pipe rehabilitation applications such as reinforcing and repairing existing pipes. Among these, it is preferable to use it as a material for lining materials, etc. In other words, it is preferable for the composite material to be used for pipe rehabilitation.

The amount of resin composition contained in the composite material is not particularly limited, but from the viewpoint of mechanical strength, it is preferably 20 to 95% by mass, more preferably 25 to 85% by mass, and even more preferably 25 to 75% by mass. If the amount of resin composition is 20% by mass or more, it is possible to impart a suitable degree of flexibility to the composite material containing the cured resin composition. If the amount of resin composition is 95% by mass or less, it is possible to impart sufficient strength to the composite material containing the cured resin composition.

[Fiber base material (F)]
Examples of the fiber base material (F) include so-called reinforced fibers such as synthetic fibers such as amide, aramid, vinylon, polyester, and phenolic resin, carbon fibers, glass fibers, metal fibers, and ceramic fibers, as well as composite fibers thereof, from the viewpoint of mechanical strength, etc. Among these, aramid fibers, polyester fibers, and glass fibers are preferred, and glass fibers are more preferred from the viewpoints of strength, availability, price, etc. In particular, from the viewpoint of photocuring the resin composition impregnated into the fiber base material (F), it is preferable to use at least one type selected from glass fibers and polyester fibers having optical transparency.
The fibrous base material (F) may be used alone or in combination of two or more kinds.
For example, in the case of glass fibers, the filament diameters generally used are preferably 1 to 15 μm, more preferably 3 to 10 μm.

Examples of the form of the fiber substrate (F) include sheets, chopped strands, chopped, milled fibers, etc. Examples of the sheet include those formed by aligning a plurality of 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 fiber substrate (F) may be used alone or in combination of two or more types, and may be a single layer or a multi-layer laminate.
From the viewpoint of impregnation with the resin composition, the thickness of the fiber substrate (F) is preferably 0.01 to 5 mm in the case of a single layer, and when multiple layers are laminated, the total thickness is preferably 1 to 20 mm, more preferably 1 to 15 mm. These fiber substrates (F) may contain a known sizing agent in a known content.

When the composite material of this embodiment contains the fiber base material (F), the content is preferably 5 to 80 mass%, more preferably 15 to 75 mass%, and even more preferably 25 to 75 mass%. If the content of the fiber base material (F) is 5 mass% or more, sufficient strength can be imparted to the composite material containing the cured resin composition. If the content of the fiber base material (F) is 80 mass% or less, appropriate flexibility can be imparted to the composite material containing the cured resin composition.

[Filler (G)]
Examples of the filler include aluminum oxide, aluminum hydroxide, silica sand, calcium carbonate, glass powder, talc, fused silica, etc. Among these, from the viewpoint of the mechanical strength of the cured product, at least one selected from aluminum hydroxide and calcium carbonate is preferable.

When the composite material of this embodiment contains a filler (G), the content thereof is preferably 10 to 100 parts by mass, more preferably 15 to 90 parts by mass, and even more preferably 20 to 80 parts by mass, per 100 parts by mass of the resin composition. If the content of the filler (G) is 10 parts by mass or more per 100 parts by mass of the resin composition, the mechanical strength of the cured product can be further increased. If the content of the filler (G) is 100 parts by mass or less, the toughness and strength of the cured product can be compatible.

The mechanical strength required for the cured composite material (fiber reinforced plastic: FRP) varies depending on the intended use, but for example, in a composite material using a glass fiber substrate, the bending strength of the FRP is generally preferably 100 to 1000 MPa, more preferably 150 to 800 MPa. The bending modulus of the FRP is preferably 5 to 40 GPa, more preferably 7 to 35 GPa, and even more preferably 8 to 30 GPa.
The above bending strength and bending modulus values are measured in accordance with JIS K7171:2016.

<Manufacturing method of composite materials>
The method for producing the composite material may be appropriately selected depending on the purpose, and is not particularly limited.
The composite material can be produced by impregnating the fiber substrate (F) with the resin composition and curing the resin composition at a constant temperature until the resin composition reaches a target viscosity, thereby increasing the viscosity of the resin composition. The composite material can be stored by folding the sheet-like composite material in an accordion-like manner or by rolling it up.

When the above-mentioned resin composition is impregnated into the fiber substrate (F), the resin composition may be impregnated into the fiber substrate (F) having an inner film and an outer film laminated on the surface, or a fiber substrate (F) having no inner film and no outer film laminated on the surface may be used.
In addition, when a fiber base material (F) having an inner film and an outer film laminated on the surface is used, the resin composition is impregnated into the fiber base material (F) through at least one of the inner film and the outer film.

[Inner film]
The inner film may be, for example, a resin film such as a polyethylene film, a polypropylene film, or a polyethylene terephthalate film. The inner film is preferably permeable. The inner film may be peeled off after the composite material is cured.

The thickness of the inner film is not particularly limited, but is preferably 50 to 200 μm, and more preferably 80 to 170 μm. If the thickness of the inner film is 50 μm or more, the inner film can be prevented from being damaged or wrinkled, and sufficient strength can be imparted to the pipe. If the thickness of the inner film is 200 μm or less, the composite material can be easily manufactured, and the pipe rehabilitation workability is good.

The inner film may be laminated before the fibrous base material (F) is impregnated with the resin composition, or may be laminated on the fibrous base material (F) impregnated with the resin composition (resin composition-impregnated base material).
The method for laminating the inner film is not particularly limited, but examples thereof include a method of applying a liquid film composition to a fiber substrate (F) and curing the composition to laminate, a method of laminating a film on a fiber substrate (F) or a substrate impregnated with a resin composition via an adhesive layer, a method of laminating a film on a fiber substrate (F) or a substrate impregnated with a resin composition, etc. The inner film and the outer film may be laminated using different methods or the same method.

[Outer film]
The outer film may be a resin film, similar to the inner film. The outer film preferably has a light-shielding property. For example, a laminated film having a colored film layer, such as yellow, between two transparent polyethylene films may be used as the outer film having a light-shielding property.

The thickness of the outer film is not particularly limited, but is preferably 5 to 100 μm, and more preferably 10 to 90 μm. If the thickness of the outer film is 5 μm or more, the outer film will not break or wrinkle, and sufficient strength can be imparted to the pipe. If the thickness of the outer film is 100 μm or less, the composite material can be easily manufactured, and the pipe rehabilitation workability is good.

The outer film may be laminated before the fibrous base material (F) is impregnated with the resin composition, or may be laminated on the fibrous base material (F) impregnated with the resin composition (resin composition-impregnated base material).
The method for laminating the outer film onto the fiber base material (F) is not particularly limited, but may be the same method as the method for laminating the inner film.

<Pipe rehabilitation>
The introduction of the lining material (composite material) into an existing pipe can be performed by pulling the lining material directly from a manhole or the like, but an inversion method in which the lining material is inverted from the tip side and pushed into the existing pipe is preferably used. A lining material containing an outer film as the innermost layer on the inner surface, an inner film as the outermost layer on the outer surface, and a fiber base material (F) containing a resin composition between the inner film and the outer film is preferably used for the inversion method.
The lining material is expanded by blowing air into the lumen of the lining material, so both ends of the lining material have end packers to seal the lining material. By blowing air into the end packer side at one end, the pressure in the lumen of the lining material increases, and the lining material is expanded in diameter so that it comes into close contact with the inner circumferential surface of the existing pipe.

The expanded lining material is irradiated with ultraviolet light or visible light or the like by a mobile light irradiation device, so that the resin composition contained in the lining material is cured, and the inner surface of the existing pipe is covered with the lining material of the cured resin composition. The radiation intensity of the light irradiation device is not particularly limited, but is preferably 0.0008 to 0.03 W/ ^mm2 .

If the radiation intensity is 0.0008 W/ ^mm2 or more, the work efficiency is good and sufficient strength can be imparted to the pipe. If the radiation intensity is 0.03 W/ ^mm2 or less, local excessive irradiation of the inner surface layer of the lining material is suppressed, and deterioration and reduction in strength of the lining material can be suppressed.

The light irradiation device may be a light source that emits light in the ultraviolet to visible light range (usually with a wavelength of 200 to 800 nm). Examples of the light source include metal halide lamps such as gallium lamps, mercury lamps, chemical lamps, xenon lamps, halogen lamps, mercury halogen lamps, carbon arc lamps, incandescent lamps, laser light, and LEDs.
From the viewpoint of work efficiency during pipe rehabilitation work, an ultraviolet or visible light irradiation device having a peak wavelength in the wavelength range of 350 to 450 nm is preferred, and from the viewpoint of efficiently curing the resin composition, a gallium lamp and an LED are more preferred, and a gallium lamp is even more preferred.

There are no particular limitations on the light irradiation device as long as it has one or more irradiation units, but it is preferable for it to have a lamp assembly in which multiple light irradiation lamps are connected in series. By having a lamp assembly, pipe rehabilitation can be carried out efficiently.

The present invention will be explained in more detail below with reference to examples and comparative examples, but the present invention is not limited to the following examples.

[Synthesis of unsaturated polyester resin (A)]
An unsaturated polyester resin (A) was synthesized according to the following synthesis example.
The details of the compounds used in the synthesis of the unsaturated polyester resin (A) in the following synthesis examples are shown below.

(Diol (a1))
Ethylene glycol: manufactured by Mitsubishi Chemical Corporation Propylene glycol: manufactured by Dow Chemical Japan Co., Ltd. Diethylene glycol 2-methyl-1,3-propanediol: manufactured by Dalian Chemical Industry Co., Ltd. 2,2-dimethyl-1,3-propanediol: manufactured by Mitsubishi Gas Chemical Company, Inc.

(Dibasic acid (a2))
<Ethylenically unsaturated group-containing dibasic acid (a2-1)>
・Maleic anhydride: Mitsubishi Gas Chemical Company, Inc.

<Saturated dibasic acid (a2-2)>
・Phthalic anhydride: Kawasaki Chemical Industries, Ltd. ・Isophthalic acid: Mitsubishi Gas Chemical Company, Inc. ・Terephthalic acid: Mitsui Chemicals, Inc.

[Synthesis Example 1]
Into a 3 L four-neck separable flask equipped with a thermometer, a stirrer, an inert gas inlet tube, and a reflux condenser, 224.6 g of propylene glycol (27.5 mol % relative to 100 mol % of diol (a1)), 810.5 g of 2,2-dimethyl-1,3-propanediol (72.5 mol % relative to 100 mol % of diol (a1)) as the diol (a1), 47 g of isophthalic acid (a2-2) as the saturated dibasic acid (a2-3), and 2.6 g (26.5 mol % relative to 100 mol % of diol (a1)), 356.6 g of terephthalic acid (20.0 mol % relative to 100 mol % of diol (a1)), and 563.1 g of maleic anhydride (53.5 mol % relative to 100 mol % of diol (a1)) as an ethylenically unsaturated group-containing dibasic acid (a2-1) were added and subjected to a condensation reaction at 215° C. for 10 hours to obtain an unsaturated polyester resin (A-1).

[Synthesis Examples 2 and 3]
Synthesis was carried out in the same manner as in Synthesis Example 1, except that the raw materials and compounding ratios shown in Table 1 were used, to obtain unsaturated polyester resins (A-2) and (A-3).

[Synthesis of vinyl ester resin]
Vinyl ester resins were synthesized according to the following Synthesis Examples and Comparative Synthesis Examples.
Details of the compounds used in the synthesis of vinyl ester resins in the following Synthesis Examples and Comparative Synthesis Examples are given below.

(Epoxy compound (b1-1))
Epoxy compound (1): bisphenol A type epoxy resin; "Epomic (registered trademark) R140P", manufactured by Mitsui Chemicals, Inc., epoxy equivalent 188, liquid at 25°C. Epoxy compound (2): bisphenol A type epoxy resin; "jER (registered trademark) 834", manufactured by Mitsubishi Chemical Corporation, epoxy equivalent 245, liquid at 25°C. Epoxy compound (3): bisphenol A type epoxy resin; "Epotohto (registered trademark) YD-7011", manufactured by Nippon Steel Chemical & Material Co., Ltd., epoxy equivalent 475, solid at 25°C. Epoxy compound (4): bisphenol A type epoxy resin; "Epotohto (registered trademark) YD-014", manufactured by Nippon Steel Chemical & Material Co., Ltd., epoxy equivalent 950, solid at 25°C. Epoxy compound (5): phenol novolac type epoxy resin; "EPICLON (registered trademark) N-740", manufactured by DIC Corporation, epoxy equivalent 172, liquid at 25°C. The epoxy equivalent is a value measured in accordance with JIS K7236:2001.

(Bisphenol compound (b1-2))
Bisphenol A: manufactured by Mitsui Chemicals, Inc.

(Unsaturated monobasic acid (b1-3))
・Methacrylic acid: Mitsubishi Chemical Corporation ・Acrylic acid: Nippon Shokubai Co., Ltd.

(Unsaturated polybasic acid (b1-4))
・Fumaric acid: Fuso Chemical Co., Ltd.

(Reactive Diluent (Ethylenically Unsaturated Group-Containing Monomer (C)))
- Styrene: Manufactured by Idemitsu Kosan Co., Ltd.

[Synthesis Example 4]
In a 5 L four-neck separable flask equipped with a stirrer, a reflux condenser, a gas inlet tube and a thermometer, 362 g of epoxy compound (1) as epoxy compound (b1-1) and 55 g of bisphenol A as bisphenol (b1-2) (the total amount of hydroxyl groups of bisphenol A is 25 moles per 100 moles of the total amount of epoxy groups of epoxy compound (1)) were placed and heated to 80° C. Next, 0.6 g of triethylamine (manufactured by Daicel Corporation) (0.15 parts by mass per 100 parts by mass of the total of epoxy compound (b1-1) and bisphenol (b1-2)) was placed as an esterification catalyst, and the mixture was heated to 145° C. and reacted for 1 hour to synthesize a resin precursor (P1). Next, after cooling to 110°C, 94 g of styrene (9.4 mass% based on the total mass of the blended components) as a reactive diluent (ethylenically unsaturated group-containing monomer (C)), 0.01 g of 5% copper naphthenate (0.0019 mass parts per 100 parts by mass of the epoxy compound (b1-1), bisphenol (b1-2), and unsaturated monobasic acid (b1-3) in total), 0.2 g of methylhydroquinone (0.04 mass parts per 100 parts by mass of the epoxy compound (b1-1), bisphenol (b1-2), and unsaturated monobasic acid (b1-3) in total), 0.3 g of trimethylhydroquinone (0.057 mass parts per 100 parts by mass of the epoxy compound (b1-1), bisphenol (b1-2), and unsaturated monobasic acid (b1-3) in total), and unsaturated polybasic acid were added as a polymerization inhibitor. 6.7 g of fumaric acid (the total amount of acid groups of fumaric acid was 6 moles per 100 moles of the total amount of epoxy groups of epoxy compound (1)) was added as (b1-4), and 1.6 g of 2,4,6-tris(dimethylaminomethyl)phenol ("Seikuol TDMP", manufactured by Seiko Chemical Co., Ltd., purity of more than 95 mass%) was added as an esterification catalyst (0.3 part by mass per 100 parts by mass of the total of epoxy compound (b1-1), bisphenol (b1-2), and unsaturated monobasic acid (b1-3)). Further, 76 g of methacrylic acid (the total amount of acid groups of methacrylic acid was 69 moles per 100 moles of the total amount of epoxy groups of epoxy compound (1)) was added dropwise as unsaturated monobasic acid (b1-3) at 110° C. over a period of about 30 minutes, and the mixture was allowed to react for about 2 hours to obtain a vinyl ester resin (B1-1a).
The obtained vinyl ester resin (B1-1a) was cooled to 90° C., and 366 g (36 mass % based on the total mass of the blended components) of styrene was added as a reactive diluent (ethylenically unsaturated group-containing monomer (C)) to the vinyl ester resin (B1-1a), to obtain a mixture of 54 mass % of the vinyl ester resin (B1-1a) (based on the total mass of the blended components) and 46 mass % of styrene.

[Synthesis Example 5]
Into a 5 L four-neck separable flask equipped with a stirrer, a reflux condenser, a gas inlet tube, and a thermometer, 470 g of epoxy compound (1) as epoxy compound (b1-1) was placed and heated to 80° C., and then 88.4 g of styrene (10 mass % based on the total mass of the blended components) as a reactive diluent (ethylenically unsaturated group-containing monomer (C)), 0.01 g of 5% copper naphthenate (0.0014 parts by mass relative to 100 parts by mass of the epoxy compound (b1-1) and the unsaturated monobasic acid (b1-3)), 0.2 g of methylhydroquinone (0.03 parts by mass relative to 100 parts by mass of the epoxy compound (b1-1) and the unsaturated monobasic acid (b1-3)), and 0.4 g of trimethylhydroquinone (epoxy Compound (b1-1) and unsaturated monobasic acid (b1-3) in a total of 0.057 parts by mass relative to 100 parts by mass of the total, and 2.1 g of 2,4,6-tris(dimethylaminomethyl)phenol ("Seikuol TDMP", manufactured by Seiko Chemical Industry Co., Ltd., purity over 95 mass%) as an esterification catalyst (0.3 parts by mass relative to 100 parts by mass of the total of epoxy compound (b1-1) and unsaturated monobasic acid (b1-3)) were added and heated to 100°C, and then 215 g of methacrylic acid (the total amount of acid groups of methacrylic acid is 100 mol relative to 100 mol of the total amount of epoxy groups of epoxy compound (1)) was added dropwise as unsaturated monobasic acid (b1-3) over a period of about 30 minutes, and the mixture was allowed to react for about 2 hours to obtain vinyl ester resin (B1-2a).
The obtained vinyl ester resin (B1-2a) was cooled to 90° C., and 206 g (20 mass % based on the total mass of the blended components) of styrene was added as a reactive diluent (ethylenically unsaturated group-containing monomer (C)) to the vinyl ester resin (B1-2a), to obtain a mixture of 70 mass % of the vinyl ester resin (B1-2a) (based on the total mass of the blended components) and 30 mass % of styrene.

[Synthesis Example 6]
Into a 5 L four-neck separable flask equipped with a stirrer, a reflux condenser, a gas inlet tube, and a thermometer, 137 g of the epoxy compound (1) as the epoxy compound (b1-1) and 306 g of the epoxy compound (5) were placed and heated to 80° C., and then 101 g of styrene (10 mass % based on the total mass of the blended components) as a reactive diluent (ethylenically unsaturated group-containing monomer (C)), 0.02 g of 5% copper naphthenate (0.003 parts by mass relative to 100 parts by mass of the epoxy compound (b1-1) and the unsaturated monobasic acid (b1-3)), 0.5 g of methylhydroquinone (0.07 parts by mass relative to 100 parts by mass of the epoxy compound (b1-1) and the unsaturated monobasic acid (b1-3)), and 0.3 g of trimethylhydroquinone (epoxy compound (b1-1) and 0.4 ... The mixture was heated to 100° C., and then 208 g of methacrylic acid (the total amount of acid groups of methacrylic acid is 100 moles per 100 moles of the total amount of epoxy groups of epoxy compound (1) and epoxy compound (5)) was added dropwise over a period of about 30 minutes. The mixture was then allowed to react for about 2 hours to obtain a vinyl ester resin (B1-2b).
The obtained vinyl ester resin (B1-2b) was cooled to 90° C., and 244 g (25 mass % based on the total mass of the blended components) of styrene was added as a reactive diluent (ethylenically unsaturated group-containing monomer (C)) to the vinyl ester resin (B1-2b), to obtain a mixture of 65 mass % of the vinyl ester resin (B1-2b) (based on the total mass of the blended components) and 35 mass % of styrene.

[Synthesis Example 7]
Into a 5 L four-neck separable flask equipped with a stirrer, a reflux condenser, a gas inlet tube, and a thermometer, 113 g of the epoxy compound (2) was placed as the epoxy compound (b1-1), and the mixture was heated to 80° C., and then 0.002 g of 5% copper naphthenate (0.0014 parts by mass relative to 100 parts by mass of the epoxy compound (b1-1) and the unsaturated monobasic acid (b1-3) in total), 0.04 g of methylhydroquinone (0.03 parts by mass relative to 100 parts by mass of the epoxy compound (b1-1) and the unsaturated monobasic acid (b1-3) in total), 0.1 g of trimethylhydroquinone (0.02 parts by mass relative to 100 parts by mass of the epoxy compound (b1-1) and the unsaturated monobasic acid (b1-3) in total), and 0.1 g of trimethylhydroquinone (0.02 parts by mass relative to 100 parts by mass of the epoxy compound (b1-1) and the unsaturated monobasic acid (b1-3) in total) were added as a polymerization inhibitor. To the mixture was added 0.07 parts by mass relative to a total of 100 parts by mass of epoxy compound (b1-1) and unsaturated monobasic acid (b1-3), and 0.1 g of benzyltriphenylphosphonium chloride ("TPP-ZC", manufactured by Hokko Chemical Industry Co., Ltd.) as an esterification catalyst (0.08 part by mass relative to a total of 100 parts by mass of epoxy compound (b1-1) and unsaturated monobasic acid (b1-3)), and the mixture was heated to 100° C., and then 8.6 g of methacrylic acid (the total amount of acid groups of methacrylic acid is 50 mol relative to 100 mol of the total amount of epoxy groups of epoxy compound (2)) as unsaturated monobasic acid (b1-3) was added dropwise over a period of about 30 minutes, followed by reaction for about 2 hours to obtain a vinyl ester resin (B1-2c).
The obtained vinyl ester resin (B1-2c) was cooled to 90° C., and 59.6 g (24 mass % based on the total mass of the blended components) of styrene was added as a reactive diluent (ethylenically unsaturated group-containing monomer (C)) to the vinyl ester resin (B1-2c), to obtain a mixture of 70 mass % of the vinyl ester resin (B1-2c) (based on the total mass of the blended components) and 30 mass % of styrene.

[Comparative Synthesis Example 1]
In a 5 L four-neck separable flask equipped with a stirrer, a reflux condenser, a gas inlet tube and a thermometer, 348 g of epoxy compound (1) as epoxy compound (b1-1) and 99 g of bisphenol A as bisphenol (b1-2) (the total amount of hydroxyl groups of bisphenol A is 47 moles per 100 moles of the total amount of epoxy groups of epoxy compound (1)) were placed and heated to 80° C. Next, 0.9 g of triethylamine (manufactured by Daicel Corporation) (0.2 parts by mass per 100 parts by mass of the total of epoxy compound (b1-1) and bisphenol (b1-2)) was placed as an esterification catalyst, and the mixture was heated to 145° C. and reacted for 1 hour to synthesize a resin precursor (P1). Next, after cooling to 110°C, 114 g of styrene (10% by mass based on the total mass of the blended components) was added as a reactive diluent (ethylenically unsaturated group-containing monomer (C)), 0.01 g of 5% copper naphthenate (0.0019 parts by mass based on 100 parts by mass of the total of the epoxy compound (b1-1), bisphenol (b1-2), and unsaturated monobasic acid (b1-3)), 0.16 g of methylhydroquinone (0.03 parts by mass based on 100 parts by mass of the total of the epoxy compound (b1-1), bisphenol (b1-2), and unsaturated monobasic acid (b1-3)), 0.3 g of trimethylhydroquinone (0.02 parts by mass based on 100 parts by mass of the total of the epoxy compound (b1-1), bisphenol (b1-2), and unsaturated monobasic acid (b1-3)), and 0.2 g of methylhydroquinone (0.02 parts by mass based on 100 parts by mass of the total of the epoxy compound (b1-1), bisphenol (b1-2), and unsaturated monobasic acid (b1-3)) were added as a polymerization inhibitor. To the mixture was added 1.6 g of 2,4,6-tris(dimethylaminomethyl)phenol ("Seikuol TDMP", manufactured by Seiko Chemical Co., Ltd., purity over 95% by mass) as an esterification catalyst (0.3 g of 2,4,6-tris(dimethylaminomethyl)phenol per 100 parts by mass of the epoxy compound (b1-1), bisphenol (b1-2), and unsaturated monobasic acid (b1-3)), and the mixture was heated to 110° C., and then 84 g of methacrylic acid (the total amount of acid groups of methacrylic acid is 53 moles per 100 moles of the epoxy groups of the epoxy compound (1)) as the unsaturated monobasic acid (b1-3) was added dropwise over about 30 minutes, followed by a reaction for about 2 hours to obtain a vinyl ester resin (B'1-2a).
The obtained vinyl ester resin (B'1-2a) was cooled to 90°C, and 342 g (36 mass % based on the total mass of the blended components) of styrene was added as a reactive diluent (ethylenically unsaturated group-containing monomer (C)) to the vinyl ester resin (B'1-2a), to obtain a mixture of 54 mass % of the vinyl ester resin (B'1-2a) (based on the total mass of the blended components) and 46 mass % of styrene.

[Comparative Synthesis Example 2]
A vinyl ester resin (B'1-2b) was obtained in the same manner as in Synthesis Example 2, except that 471 g of the epoxy compound (5) was used as the epoxy compound (b1-1) and 224 g of methacrylic acid was used as the unsaturated monobasic acid (b1-3) (the total amount of acid groups in the methacrylic acid was 100 mol per 100 mol of the total amount of epoxy groups in the epoxy compound (5)).
The obtained vinyl ester resin (B'1-2b) was cooled to 90°C, and 200 g (20 mass% based on the total mass of the blended components) of styrene was added as a reactive diluent (ethylenically unsaturated group-containing monomer (C)) to the vinyl ester resin (B'1-2b), to obtain a mixture of 70 mass% of the vinyl ester resin (B'1-2b) (based on the total mass of the blended components) and 30 mass% of styrene.

[Comparative Synthesis Example 3]
In a 5 L four-neck separable flask equipped with a stirrer, a reflux condenser, a gas inlet tube, and a thermometer, 125 g of epoxy compound (4) was placed as epoxy compound (b1-1) and heated to 80° C., and then 0.05 g of hydroquinone (0.04 parts by mass relative to a total of 100 parts by mass of epoxy compound (b1-1) and unsaturated monobasic acid (b1-3)) was added as a polymerization inhibitor, and 0.3 g of diethylamine hydrochloride (manufactured by Showa Chemical Co., Ltd.) (0.2 parts by mass relative to a total of 100 parts by mass of epoxy compound (b1-1) and unsaturated monobasic acid (b1-3)) was added as an esterification catalyst, and the mixture was heated to 100° C., and then 9.5 g of acrylic acid (the total amount of acid groups of acrylic acid is 100 moles relative to a total of 100 moles of epoxy groups of epoxy compound (4)) was added dropwise as unsaturated monobasic acid (b1-3) over a period of about 30 minutes, and the mixture was allowed to react for about 2 hours to obtain vinyl ester resin (B'1-2c).

[Comparative Synthesis Example 4]
A vinyl ester resin (B'1-2d) was obtained in the same manner as in Comparative Synthesis Example 3, except that 871 g of the epoxy compound (3) was used as the epoxy compound (b1-1) and 124 g of acrylic acid was used as the unsaturated monobasic acid (b1-3) (the total amount of acid groups of the acrylic acid was 95 mol per 100 mol of the total amount of epoxy groups of the epoxy compound (3)).

[Measurement and evaluation of unsaturated polyester resin and vinyl ester resin]
The unsaturated polyester resins (A-1) to (A-3) and the vinyl ester resins (B1-1a) to (B1-2c) and (B'1-2a) to (B'1-2d) obtained in the above Synthesis Examples and Comparative Synthesis Examples were subjected to the following measurement and evaluation. The measurement and evaluation results are summarized in Tables 1 and 2 below.

[Acid value]
The acid values of the unsaturated polyester resin and the vinyl ester resin were determined by measuring the mass of potassium hydroxide required to neutralize the acid components contained in the unsaturated polyester resin and the vinyl ester resin in accordance with JIS K6901:2008 "Partial acid value (indicator titration method)".
The measurement samples of vinyl ester resins (B1-1a) to (B1-2c), (B'1-2a), and (B'1-2b) were mixtures of the vinyl ester resins obtained in the above Synthesis Examples and Comparative Synthesis Examples with reactive diluents, and the mass of potassium hydroxide required to neutralize the acid components contained in the mixtures was measured, and the acid value of the vinyl ester resins was calculated based on the measured value. An "Autoburette UCB-2000" (manufactured by Hiranuma Sangyo Co., Ltd.) was used as a titration device, and a mixed indicator of bromothymol blue and phenol red was used as an indicator.

[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 and the vinyl ester resin were measured by gel permeation chromatography (GPC) under the following conditions, and were calculated as standard polystyrene equivalent molecular weights. Mw/Mn was calculated from the values of Mn and Mw.
(Measurement condition)
Apparatus: "Shodex (registered trademark) GPC-101" (manufactured by Showa Denko K.K.)
Column: "Shodex (registered trademark) LF-804" (manufactured by Showa Denko K.K.)
Detector: Differential refractometer "Shodex (registered trademark) RI-71S" (manufactured by Showa Denko K.K.)
Column temperature: 40°C
Sample: 0.2 mass% solution of unsaturated polyester resin or vinyl ester resin in tetrahydrofuran Developing solvent: tetrahydrofuran Flow rate: 1.0 mL/min

[viscosity]
The viscosity of the vinyl ester resin was measured at a temperature of 25° C. using an E-type viscometer (RE-85U, manufactured by Toki Sangyo Co., Ltd.), cone-plate type, cone rotor 1°34′×R24, rotation speed: 50 rpm to 0.5 rpm. The measurement samples of the vinyl ester resins (B1-1a) to (B1-2c), (B′1-2a), and (B′1-2b) were mixtures of the vinyl ester resins and reactive diluents obtained in the above Synthesis Examples and Comparative Synthesis Examples.

[Production of resin composition]
Using the unsaturated polyester resins and vinyl ester resins (mixtures of vinyl ester resins and reactive diluents) produced in the above Synthesis Examples and Comparative Synthesis Examples, resin compositions were produced.
Details of the compounds used in the following Examples and Comparative Examples are given below.

(Compatibilizer (D))
Compatibilizer (D1): Zinc octoate; "Zinc hexoate 15%", manufactured by Toei Kako Co., Ltd., metal content 15% by mass, solvent component mineral spirits Compatibilizer (D2): Potassium octoate; "Potassium hexoate 10%", manufactured by Toei Kako Co., Ltd., metal content 10% by mass, solvent component ethanol (main component)
Compatibilizer (D3): Cobalt octylate; "Nikka Octycobalt 8%", manufactured by Nippon Kagaku Sangyo Co., Ltd., metal content 8% by mass, solvent component mineral spirits Compatibilizer (D4): Cobalt octylate; "PA-202A", manufactured by Nippon Kagaku Sangyo Co., Ltd., metal content 8% by mass, solvent component mineral spirits (main component)
Compatibilizer (D5): Nickel octylate; "Nikka Octyx Nickel 10%", manufactured by Nippon Chemical Industries Co., Ltd., metal content 10% by mass
Compatibilizer (D6): Copper naphthenate; "Copper naphthenate 5%", manufactured by Toei Kako Co., Ltd., metal content 5% by mass
Compatibilizer (D7): Manganese octoate; "Manganese hexoate 8%", manufactured by Toei Kako Co., Ltd., metal content 8% by mass, solvent component mineral spirits Compatibilizer (D8): Iron naphthenate; "Iron naphthenate-mineral spirits solution (Fe: 5%)", manufactured by Fuji Film Wako Pure Chemical Industries, Ltd., metal content 5% by mass, solvent component mineral spirits Compatibilizer (D9): Barium naphthenate; "Barium naphthenate-toluene solution (Ba: 4%)", manufactured by Fuji Film Wako Pure Chemical Industries, Ltd., metal content 4% by mass, solvent component toluene Compatibilizer (D10): Vanadium naphthenate; "Vanadium (III) naphthenate-toluene solution (V: 2%)", manufactured by Fuji Film Wako Pure Chemical Industries, Ltd., metal content 2% by mass, solvent component toluene Compatibilizer (D11): Bismuth naphthenate; "Bismuth (III) naphthenate-toluene solution (Bi: 7%)", manufactured by Fujifilm Wako Pure Chemical Industries, Ltd., metal content 7% by mass, solvent component toluene Compatibilizer (D12): Yttrium naphthenate; "Yttrium naphthenate-toluene solution (Y: 5%)", manufactured by Fujifilm Wako Pure Chemical Industries, Ltd., metal content 5% by mass, solvent component toluene Compatibilizer (D13): Chromium naphthenate; "Chromium naphthenate", manufactured by Yoshida Chemical Industry Co., Ltd., metal content N-Cr 42 to 46% by mass, solvent component mineral spirits Compatibilizer (D14): Calcium naphthenate; "Calcium naphthenate-mineral spirits solution (Ca: 3%)", manufactured by Fujifilm Wako Pure Chemical Industries, Ltd., metal content 3% by mass, solvent component mineral spirits

(Polymerization initiator (E))
Photopolymerization initiator (E1): phenylbis(2,4,6-trimethylbenzoyl)phosphine oxide; "Omnirad 819" manufactured by IGM RESINS Photopolymerization initiator (E2): 2,2-dimethoxy-2-phenylacetophenone; "Omnirad 651" manufactured by IGM RESINS

[Example 1]
The components (A) to (C) were mixed so that the unsaturated polyester resin (A-1) was 42.9% by mass, the vinyl ester resin (B1-1a) was 15.3% by mass, and styrene as the ethylenically unsaturated group-containing monomer (C) was 41.8% by mass, relative to 100 parts by mass in total of the components (A) to (C). Then, 0.18 parts by mass of a photopolymerization initiator (E1) and 0.05 parts by mass of a photopolymerization initiator (E2) were added to the mixture as the polymerization initiator (E), relative to 100 parts by mass in total of the components (A) to (C). The mixture was mixed at 20 to 30° C. and a rotation speed of 2000 to 3000 rpm for 10 minutes using a disper (high-speed disperser "Homo Disper 2.5 type", manufactured by Primix Corporation). To this was added 0.94 parts by mass of compatibilizer (D1) as compatibilizer (D) per 100 parts by mass of the total of components (A) to (C) (1,399 ppm by mass in terms of metal content with respect to the total of components (A) to (E)), and the mixture was further mixed for about 5 minutes to prepare resin composition (X-1).

[Examples 2 to 13, Comparative Examples 1 to 20]
Resin compositions (X-2) to (X-13) and (X'-1) to (X'-20) were prepared in the same manner as in Example 1, except that the raw materials and compounding ratios were as shown in Tables 3, 4-1, and 4-2.

[Measurement and Evaluation of Resin Composition]
The resin compositions (X-1) to (X-13) and (X'-1) to (X'-20) obtained in the above Examples and Comparative Examples were evaluated as follows. The results are shown in Tables 3, 4-1, and 4-2.

[Color]
The color of the resin composition immediately after preparation was evaluated visually.

[exterior]
The measurement and evaluation samples of the above resin compositions (X-1) to (X-13) and (X'-1) to (X'-20) were stored in a refrigerator at 4 to 5°C, and the turbidity of the resin compositions was visually confirmed after 2 hours, 6 hours, and 24 hours, and evaluated according to the following evaluation criteria.
(Evaluation criteria)
A: No turbidity B: Slightly turbid C: Turbidity

[Haze (%)]
The measurement and evaluation samples of the above resin compositions (X-1) to (X-13) and (X'-1) to (X'-20) were stored in a refrigerator at 4 to 5°C, and the haze (%) of the resin composition after 24 hours was measured using a haze meter "HM-150" manufactured by Murakami Color Research Laboratory Co., Ltd.

[Total light transmittance (%)]
The measurement and evaluation samples of the above resin compositions (X-1) to (X-13) and (X'-1) to (X'-20) were stored in a refrigerator at 4 to 5°C, and the total light transmittance (%) of the resin composition after 24 hours was measured using a haze meter "HM-150" manufactured by Murakami Color Research Laboratory Co., Ltd.

[Compatibility]
After 24 hours, the resin composition was evaluated for compatibility based on the results of measuring the appearance, haze (%), and total light transmittance (%) according to the following evaluation criteria.
(Evaluation criteria)
(1) A case in which the haze (%) was less than 35, the total light transmittance (%) was 79 or more, and the appearance was "A: no turbidity" was rated as "A: very good compatibility."
(2) A case in which the haze (%) was 35 or more, the total light transmittance (%) was 79 or more, and the appearance was "A: no turbidity" was rated as "B: good compatibility."
(3) When the haze (%) was 35 or more and the total light transmittance (%) was 79 or more, and the appearance was "C: Cloudy" or "B: Slightly cloudy", it was rated as "C: Not very compatible".
(4) Those that do not fall under the above (1) to (3) were categorized as "D: poor compatibility."

[Production of Cured Product]
[Production of Cured Products (X1) and (X'1)]
The measurement and evaluation samples of the resin compositions (X-1) to (X-13), and (X'-1) to (X'-20) were stored at 23°C for 24 hours, then transferred to 100 ml disposable cups and irradiated with light for 20 minutes using an LED lamp (UV-LED irradiator H-4MLH84-V2-1S12-SM1, manufactured by HOYA Corporation, peak wavelength 385 nm, illuminance 20 mW/ ^cm2 , illuminometer: UIT-201, receiver: UPD-405PD, sensitivity wavelength range 330 to 490 nm, manufactured by Ushio Inc.) to obtain cylindrical cured products (X1-1) to (X1-13), and (X'1-1) to (X'1-20) (cast products) having a diameter of 40 mm and a thickness of 60 mm.

[Production of Cured Products (X2) and (X'2)]
The measurement and evaluation samples of the resin compositions (X-1) to (X-13), and (X'-1) to (X'-20) were stored at 23°C for 24 hours, then transferred to 100 ml disposable cups and irradiated with light for 20 minutes using a gallium lamp ("Unilec URM-300I", manufactured by Ushio Lighting Inc., illuminance 20 mW/ ^cm2 , illuminometer: UIT-201, receiver: UPD-405PD, sensitivity wavelength range 330 to 490 nm, manufactured by Ushio Inc.) to obtain cylindrical cured products (X2-1) to (X2-13), and (X'2-1) to (X'2-20) (cast products) having a diameter of 40 mm and a thickness of 60 mm.

[Production of Cured Products (X3) and (X'3)]
The measurement and evaluation samples of the resin compositions (X-1) to (X-13), and (X'-1) to (X'-20) were stored at 4 to 5°C for 24 hours, then transferred to 100 ml disposable cups and irradiated with light for 20 minutes using an LED lamp (UV-LED irradiator H-4MLH84-V2-1S12-SM1, manufactured by HOYA Corporation, peak wavelength 385 nm, illuminance 20 mW/ ^cm2 , illuminometer: UIT-201, receiver: UPD-405PD, sensitivity wavelength range 330 to 490 nm, manufactured by Ushio Inc.) to obtain cylindrical cured products (X3-1) to (X3-13), and (X'3-1) to (X'3-20) (cast products) having a diameter of 40 mm and a thickness of 60 mm.

[Production of Cured Products (X4) and (X'4)]
The measurement and evaluation samples of the resin compositions (X-1) to (X-13), and (X'-1) to (X'-20) were stored at 4 to 5°C for 24 hours, then transferred to 100 ml disposable cups and irradiated with light for 20 minutes using a gallium lamp ("Unilec URM-300I", manufactured by Ushio Lighting Inc., illuminance 20 mW/ ^cm2 , illuminometer: UIT-201, receiver: UPD-405PD, sensitivity wavelength range 330 to 490 nm, manufactured by Ushio Inc.) to obtain cylindrical cured products (X4-1) to (X4-13), and (X'4-1) to (X'4-20) (cast products) having a diameter of 40 mm and a thickness of 60 mm.

[Production of Cured Products (X5) and (X'5)]
The measurement and evaluation samples of the resin compositions (X-1) to (X-13), and (X'-1) to (X'-20) were stored at 4 to 5°C for 24 hours, and then transferred to a tin cap (cylindrical container, inner diameter 60 mm, depth 10 mm) and irradiated with light for 5 minutes using an LED lamp ("NT400405-AS-FBG-ST", manufactured by T-Net Japan Co., Ltd., peak wavelength 385 nm, illuminance 7.5 mW/cm ² , illuminometer: UIT-201, receiver: UPD-405PD, sensitivity wavelength range 330 to 490 nm, manufactured by Ushio Inc.) to obtain cylindrical cured products (X5-1) to (X5-13), and (X'5-1) to (X'5-20) (cast products) having a diameter of 60 mm and a thickness of 7.5 mm.

(6) Production of Cured Products (X6) and (X'6) Measurement and evaluation samples of the resin compositions (X-1) to (X-13), and (X'-1) to (X'-20) were stored at 4 to 5°C for 24 hours, and then transferred to a tin cap (cylindrical container, inner diameter 60 mm, depth 10 mm) and irradiated with light for 5 minutes using a gallium lamp ("Unilec URM-300I", manufactured by Ushio Lighting Inc., illuminance 5.5 mW/ ^cm2 , illuminometer: UIT-201, receiver: UPD-405PD, sensitivity wavelength range 330 to 490 nm, manufactured by Ushio Inc.) to obtain cylindrical cured products (X6-1) to (X6-13), and (X'6-1) to (X'6-20) (cast products) having a diameter of 60 mm and a thickness of 7.5 mm.

[Measurement and Evaluation of Cured Resin Composition]
[Photocuring]
(hardening depth)
The uncured resin-like and gel-like parts were removed with a cutter knife from the back side of the light-irradiated surface of the cured products (X1) to (X4) and (X'1) to (X'4) to obtain a completely cured part. The height from the irradiated surface to the back side of the irradiated surface was measured at three points with a vernier caliper, and the average value was used as the cure depth.

(exterior)
The cured products (X1) to (X4) and (X'1) to (X'4) were visually observed and evaluated according to the following evaluation criteria.
[Evaluation criteria]
A: No turbidity B: Slightly turbid C: Turbid

(Photocuring (Evaluation))
The cured products (X3), (X4), (X'3) and (X'4) were evaluated for their depth of cure according to the following evaluation criteria.
<Evaluation criteria>
A (good photocuring properties): The cured depth of both cured products X3 and X4 is 35 mm or more. B (not very good photocuring properties): The cured depth of at least one of cured products X3 and X4 is 30 mm or more and less than 35 mm. C (poor photocuring properties): The cured depth of at least one of cured products X3 and X4 is less than 30 mm.

[Cure properties]
(Barcol hardness)
The cured products (X5), (X6), (X'5), and (X'6) were used as test pieces for measurement and evaluation. In accordance with JIS K7060:1995, a Barcol hardness tester ("GYZJ 934-1", manufactured by Barber Coleman) was pressed against the back side of the light irradiated surface of the test pieces for measurement and evaluation, the Barcol hardness of the test pieces for measurement and evaluation was measured at 10 points, and the average value was regarded as the Barcol hardness of the cured products.
The cured physical properties of each cured product were evaluated according to the following evaluation criteria.
<Evaluation criteria>
A (excellent curability): Barcol hardness of 21 or more B (good curability): Barcol hardness of 16 or more and less than 21 C (not very good curability): Barcol hardness of 11 or more and less than 16 D (poor curability): Barcol hardness less than 11

(Cure Properties (Evaluation))
From the results of the Barcol hardness measurements, the cured physical properties of the resin compositions were evaluated according to the following evaluation criteria.
<Evaluation criteria>
A (excellent curability): The Barcol hardness of both the cured product (X5) and the cured product (X6) is 21 or more. B (good curability): The Barcol hardness of one of the cured products (X5) and (X6) is 21 or more, and the Barcol hardness of the other is 16 or more and less than 21. C (not very good curability): The Barcol hardness of one of the cured products (X5) and (X6) is 16 or more, and the Barcol hardness of the other is 11 or more and less than 16. D (poor curability): The Barcol hardness of at least one of the cured products (X5) and (X6) is less than 11.

As can be seen from the evaluation results shown in Tables 3, 4-1, and 4-2, the resin compositions of the present invention (Examples 1 to 13) were found to have high transparency, excellent compatibility and curing properties, and were less likely to cause curing defects.

Claims

An unsaturated polyester resin (A),
A (meth)acryloyloxy group-containing resin (B),
An ethylenically unsaturated group-containing monomer (C), a compatibilizer (D), and
A polymerization initiator (E);
A resin composition comprising:
the (meth)acryloyloxy group-containing resin (B) is a resin having two or more (meth)acryloyloxy groups in one molecule and a weight average molecular weight (Mw) of 500 to 3,000;
The (meth)acryloyloxy group-containing resin (B) contains a vinyl ester resin (B1),
the vinyl ester resin (B1) is an addition reaction product of raw materials containing an epoxy compound (b1-1) and an unsaturated monobasic acid (b1-3),
the epoxy compound (b1-1) contains 30 to 100 mass% of a bisphenol type epoxy resin having an epoxy equivalent of 300 or less, based on 100 mass% of the epoxy compound (b1-1);
the compatibilizer (D) is an organometallic compound containing at least one metal element selected from the group consisting of metal elements of groups 1, 12, and 14;
The resin composition has a metal-equivalent content of the compatibilizer (D) of 800 to 1,850 ppm by mass based on the total content of the unsaturated polyester resin (A), the (meth)acryloyloxy group-containing resin (B), the ethylenically unsaturated group-containing monomer (C), the compatibilizer (D), and the polymerization initiator (E).
The resin composition according to claim 1, wherein the ratio of the weight average molecular weight (Mw) of the unsaturated polyester resin (A) to the weight average molecular weight (Mw) of the (meth)acryloyloxy group-containing resin (B) (weight average molecular weight (Mw) of the unsaturated polyester resin (A)/weight average molecular weight (Mw) of the (meth)acryloyloxy group-containing resin (B)) is 1.5 to 30.
The resin composition according to claim 1, wherein the unsaturated polyester resin (A) is an unsaturated polyester resin obtained by esterification reaction of a diol (a1), an ethylenically unsaturated group-containing dibasic acid (a2-1), and a saturated dibasic acid (a2-2).
The resin composition according to claim 1, wherein the content of the unsaturated polyester resin (A) is 25 to 50 mass%, the content of the (meth)acryloyloxy group-containing resin (B) is 12 to 30 mass%, and the content of the ethylenically unsaturated group-containing monomer (C) is 20 to 63 mass%, relative to a total of 100 mass% of the unsaturated polyester resin (A), the (meth)acryloyloxy group-containing resin (B), and the ethylenically unsaturated group-containing monomer (C).
The resin composition according to claim 1, wherein the metal element of the organometallic compound is at least one selected from zinc, potassium, and tin.
The resin composition according to claim 1, wherein the organometallic compound is at least one selected from zinc octoate, zinc neodecanoate, potassium octoate, tin octoate, and tin bisacetylacetonate.
The resin composition according to claim 1, wherein the polymerization initiator (E) is a photopolymerization initiator.
The resin composition according to claim 1, wherein the content of the polymerization initiator (E) is 0.02 to 10 parts by mass per 100 parts by mass of the total of the unsaturated polyester resin (A), the (meth)acryloyloxy group-containing resin (B), and the ethylenically unsaturated group-containing monomer (C).
The resin composition according to claim 1, wherein the polymerization initiator (E) is at least one selected from 2,2-dimethoxy-2-phenylacetophenone, diphenyl(2,4,6-trimethylbenzoyl)phosphine oxide, phenylbis(2,4,6-trimethylbenzoyl)phosphine oxide, and 1-hydroxycyclohexyl phenyl ketone.
The resin composition according to claim 1 ,
At least one selected from a fiber base material (F) and a filler (G);
Composite material comprising:
The composite material according to claim 10, wherein the fiber substrate (F) is at least one selected from glass fibers and polyester fibers.
The composite material according to claim 10, wherein the filler (G) is at least one selected from aluminum hydroxide and calcium carbonate.
A cured product of the resin composition according to claim 1 or the composite material according to claim 10.