Modified epoxy resin, its manufacturing method, resin composition, cured product, and decomposition method.

Abstract

The present invention provides a low-viscosity modified epoxy resin that yields a cured product with excellent biodegradability and mechanical strength, and is useful for applications such as lamination, molding, casting, and bonding; a resin composition thereof; a cured product thereof; and a method for producing the resin. [Solution] A modified epoxy resin produced by the reaction of a bifunctional epoxy resin represented by formula (4) with a diphenyl carbonate represented by formula (5). TIFF2026144033000021.tif49148 Y is a divalent group and has at least an alicyclic hydrocarbon group which may have heteroatoms, and G is a glycidyl group. 2 This is the average number of repetitions, and is between 0 and 6 (inclusive).

Description

[Technical Field]

[0001] This invention relates to a modified epoxy resin that yields a cured product with excellent biodegradability and mechanical strength, and low viscosity. It also relates to a resin composition containing this modified epoxy resin as an essential component, and its cured product, etc. [Background technology]

[0002] Epoxy resins are widely used in fields such as paints, civil engineering, adhesives, and electrical materials due to their excellent heat resistance, adhesive properties, chemical resistance, water resistance, mechanical strength, and electrical properties.

[0003] On the other hand, cured products obtained by curing thermosetting resins, including epoxy resins, are insoluble in solvents and do not dissolve even at high temperatures (infusible). As a result, they have poor recyclability and reusability, and the cured products become waste after use, making waste reduction and environmental impact mitigation challenges. Furthermore, due to their high adhesive performance, their dismantling and reuse after use are limited. Therefore, cured products using thermosetting resins require waste reduction and reusability, and imparting biodegradability is considered an effective way to achieve this.

[0004] Against this backdrop, Patent Document 1 discloses a method for decomposing a cured product by incorporating a solution-degradable carbonate structure into a thermosetting resin beforehand, and then immersing it in a specific solution after curing to break the bonds. However, the epoxy resin disclosed in Patent Document 1 had high viscosity, which limited its applications. [Prior art documents] [Patent Documents]

[0005] [Patent Document 1] Patent No. 7555376 [Overview of the project] [Problems that the invention aims to solve]

[0006] Therefore, the problem that the present invention aims to solve is to provide a modified epoxy resin with low viscosity that gives a cured product with excellent decomposability and mechanical strength, and is useful for applications such as lamination, molding, casting, and bonding, as well as a resin composition and a cured product thereof. [Means for solving the problem]

[0007] To solve the above problems, the inventors diligently studied various structures of bifunctional epoxy resins and found that modified epoxy resins having a specific structure have low viscosity, and that cured products obtained by curing such resin compositions have excellent degradability and mechanical strength, thus completing the present invention.

[0008] In other words, the present invention is a modified epoxy resin characterized by being represented by the following general formula (1). [ka] Here, X is a monovalent group represented by formula (2-1) or formula (2-2) above, and formulas (2-1) and (2-2) may be present together in one molecule. Y is a divalent group and has at least an alicyclic hydrocarbon group which may have a heteroatom. 1 n is the average number of repetitions, and is between 0 and 500 (inclusive). 1 If n is 0, then X has at least one base represented by equation (2-2). 2 This is the average number of repetitions, and is between 0 and 6 (inclusive).

[0009] In formula (1), Y is a divalent group and preferably has at least 10% by mass of an alicyclic hydrocarbon group having 1 to 15 carbon atoms, which may also have an oxygen atom.

[0010] In formula (1), Y is a divalent group, and it is preferable that it contains at least 10% by mass of a divalent group represented by the following formula (3-1) and / or formula (3-2). [ka]

[0011] The present invention also provides a resin composition comprising the above modified epoxy resin and a curing agent.

[0012] The present invention also provides a cured product obtained by curing the above resin composition, a prepreg comprising the above resin composition or a semi-cured product thereof and a fibrous base material, and a resin sheet comprising the above resin composition or a semi-cured product thereof and a support film. The present invention further provides a laminated board obtained by laminating and molding the above prepreg and / or the above resin sheet. The present invention still further provides a resin composition for fiber-reinforced composite material obtained by impregnating reinforcing fibers with the above resin composition, and a fiber-reinforced composite material obtained from the above resin composition for fiber-reinforced composite material.

[0013] The present invention also provides a method for producing the above modified epoxy resin, which comprises reacting a bifunctional epoxy resin represented by the following general formula (4) with diphenyl carbonate represented by the following formula (5).

Chemical Formula

[0014] The present invention further provides a method for decomposing the above cured product, laminated board or fiber-reinforced composite material, which comprises reacting the above cured product, laminated board or fiber-reinforced composite material with a primary amine.

Effects of the Invention

[0015] According to the present invention, there can be provided a modified epoxy resin having low viscosity and a resin composition, which provide a cured product excellent in decomposability and mechanical strength. This modified epoxy resin is excellent in decomposability, mechanical strength and viscosity, and can be suitably used for composite materials such as fiber-reinforced plastics (FRP) that require decomposability and mechanical strength, laminated boards, film adhesives, adhesives such as liquid adhesives, and the like.

Brief Description of Drawings

[0016] [Figure 1] This is the GPC chart for the modified epoxy resin of Example 1. [Figure 2] This is the IR chart for the modified epoxy resin of Example 1. [Modes for carrying out the invention]

[0017] Embodiments of the present invention will be described in detail below. However, the present invention is not limited to the embodiments and examples described below, and can be implemented with modifications as appropriate without departing from the scope of the claims and equivalents of the present invention.

[0018] The modified epoxy resin of the present invention is characterized by being represented by general formula (1), and having a structure represented by formula (2-1) or formula (2-2). Formulas (2-1) and (2-2) may be present together in a single molecule. Furthermore, it has at least a divalent alicyclic hydrocarbon group which may contain heteroatoms. [ka]

[0019] The weight-average molecular weight (Mw) of the modified epoxy resin of the present invention is preferably 250 or more and 100,000 or less. Here, if Mw is less than 250, it tends to be difficult to introduce structures that improve degradability. If Mw is greater than 100,000, compatibility tends to decrease and the resin tends to be difficult to handle. Furthermore, from the viewpoint of improving the degradability of the modified epoxy resin, Mw of 300 or more is more preferable. From the viewpoint of improving handling ease, Mw of 90,000 or less is more preferable, and 80,000 or less is even more preferable. For applications such as impregnation into a substrate, Mw of 10,000 or less is preferable, and more preferably 5,000 or less. The Mw of the modified epoxy resin can be measured by the gel permeation chromatography (GPC) method described in the examples.

[0020] If the epoxy equivalent of the modified epoxy resin is 150 to 100,000 g / eq., it is preferable that the modified epoxy resin participates in the curing reaction and can be incorporated into the crosslinked structure, so it is preferable that it be within this range. More preferably, the epoxy equivalent is 150 to 40,000 g / eq., and even more preferably 200 to 20,000 g / eq. For film applications, where film-forming ability is required, a higher epoxy equivalent is desirable, preferably 5,000 to 50,000 g / eq., more preferably 10,000 to 50,000 g / eq., and even more preferably 20,000 to 50,000 g / eq. On the other hand, for applications where the resin is impregnated into a substrate, etc., where good impregnation ability is required, a lower epoxy equivalent is preferable, preferably 150 to 10,000 g / eq., more preferably 150 to 5,000 g / eq., and even more preferably 150 to 3,000 g / eq.

[0021] In the above general formula (1), n 1 n is the number of repetitions and is the average value. Its range is 0 to 500. From the viewpoint of moldability and handling, it is preferably 0 to 200, more preferably 0 to 100, and even more preferably 0 to 50. Number of repetitions n 1 This can be calculated from the number-average molecular weight (Mn) obtained by the GPC method. 1 If n is 0, then X has at least one of the bases in equation (2-2) above. 2 This is the average value of the number of repetitions, and is between 0 and 6, preferably between 0 and 3.

[0022] In the above general formula (1), Y is a divalent group and has at least an alicyclic hydrocarbon group which may have a heteroatom.

[0023] Examples of alicyclic hydrocarbon groups that are divalent and contain heteroatoms include aziridine, oxirane, thiirane, azetidine, 1,3-diazetidine, oxetane, thiethane, β-lactam, pyrrolidine, pyrazolidine, imidazolidine, tetrahydrofuran, 1,3-dioxolane, tetrahydrothiophene, 1,2-oxathiolane, 1,3-oxathiolane, sulfolane, thiazolidione, succinimide, 2-oxazolidone, hydantoin, piperidine, piperazine, tetrahydropyran, 1,4-dioxane, thian, 1,3-dithiane, 1,4-dithiane, 1,3,5-trithiane, morpholine, thiomorpholine, thiomorpholine dioxide, pyrrolizidine, decahydroisoquinoline, decahydroquinoline, quinuclidine, 1-azaadamantane, and 2-azaadamantane. , oxepan, azocan, thiocan, azonan, 1-oxaspiro[4.5]decane, 1,6-oxaspiro[3.4]octane, 1-oxaspiro[4.4]nonane-2-one, 2-oxa-7-azaspiro[3.5]nonane, 1,4-dioxa-7-azaspiro[4.4]nonane, 1,3-diazaspiro[4.4]non-2-ene-4-one, 2,9-diazaspiro[5.5]undecane- Examples include divalent groups containing structures such as 1-one, 8-azaspiro[4.5]decane-7,9-dione, 1,3,8-triazaspiro[4.5]decane-4-one, 1,4-dithia-7-azaspiro[4.4]nonane, 2,4,8,10-tetraoxaspiro[5.5]undecane, 3,9-bis(1,1-dimethylethyl), and 1,4:3,6-dianhydro-2,5-dideoxyhexitol. These structures may be substituted with substituents.

[0024] Examples of alicyclic hydrocarbon groups that are divalent and do not contain heteroatoms include cycloalkanes such as cyclopropane, cyclobutane, cyclopentane, cyclohexane, cycloheptane, cyclooctane, cyclononane, cyclodecane, cycloundecane, cyclododecane, bicycloundecane, decahydronaphthalene, cubane, basquetan, hausan, dimethylcyclohexane, bicyclohexyl, dicyclohexylmethane, and 2,2-dicyclohexylpropane. These structures may be substituted with substituents.

[0025] In the above general formula (1), Y may have a skeleton derived from the remaining skeleton obtained by removing two glycidyloxy groups from a bifunctional epoxy resin (diglycidyl ether compound). Examples of bifunctional epoxy resins include bisphenol type epoxy resins such as bisphenol A type epoxy resin, bisphenol F type epoxy resin, bisphenolacetophenone type epoxy resin, and diphenyl ether type epoxy resin, as well as biphenol type epoxy resins, diphenyldicyclopentadiene type epoxy resin, alkylene glycol type epoxy resin, and aliphatic cyclic epoxy resin. These epoxy resins may be substituted with substituents. Calculated from the weight ratio of the raw materials, Y has at least a divalent group, which may contain heteroatoms, and is an alicyclic hydrocarbon group. From the viewpoint of improving handling, calculated from the weight ratio of the raw materials, Y has at least 10% by mass of a divalent group, which may contain heteroatoms, and is an alicyclic hydrocarbon group. More preferably 30% by mass or more, even more preferably 40% by mass or more, and even more preferably 50% by mass or more. This allows for fine-tuning of properties such as solvent solubility, decomposability, mechanical properties, adhesion, and viscosity by incorporating an appropriate amount of a bifunctional epoxy resin-derived skeleton into the modified epoxy resin of the present invention.

[0026] Among these, from the viewpoints of degradability, viscosity and the like, as the alicyclic hydrocarbon group which may optionally contain the aforementioned heteroatom, it is preferable that the alicyclic hydrocarbon group having 1 to 15 carbon atoms which may optionally contain an oxygen atom accounts for at least 10% by mass or more. More preferable Y groups are those containing at least 10% by mass or more of a divalent group represented by the following formula (3-1) and / or the following formula (3-2), and a divalent group represented by the following formula (3-1) is even more preferable. [Chemical formula]

[0027] In general formula (1), the terminal group X is a monovalent group represented by formula (2-1) or formula (2-2), and one molecule may contain both formula (2-1) and formula (2-2) in mixture. It preferably has at least a group represented by formula (2-2). In the raw material epoxy resin of general formula (4), all terminal groups are glycidyl groups of formula (2-1) represented as G, whereas in the modified epoxy resin of general formula (1), the resin reacts with diphenyl carbonate, and when calculated from the charged weight ratio of raw materials, preferably 25% by mass or more of the terminal groups are groups represented by formula (2-2). Among the terminal groups, the content of groups represented by formula (2-2) is more preferably 50% by mass or more. As for the modified epoxy resin, the molar percentage is calculated to be approximately the same as the mass percentage. The carbonate concentration of the carbonate structure containing the group represented by formula (2-2) is defined by the terminal group X and the repeating unit n in formula (1) 1 calculated as the total in the above, it is preferably 0.05 to 0.20 eq. / 100g, more preferably 0.07 to 0.17 eq. / 100g, and even more preferably 0.08 to 0.15 eq. / 100g. When the carbonate concentration falls within this range, excellent degradability, viscosity and other properties are obtained. [Chemical formula]

[0028] The modified epoxy resin of the present invention provides degradability without significantly increasing viscosity during modification. A preferred manufacturing method involves reacting a bifunctional epoxy resin represented by general formula (4) with a diphenyl carbonate represented by formula (5). [ka] In equation (4), Y is the same as in equation (1). G is a monovalent group represented by equation (2-1) above. 2 This is the average value of the number of repetitions, and is between 0 and 6, preferably between 0 and 3. In this manufacturing method, the reaction between the epoxy resin of formula (4) and the diphenyl carbonate of formula (5) is thought to occur through a mechanism in which the diphenyl carbonate undergoes phenolic dissociation and polycondensation with the epoxy group, rather than with the secondary hydroxyl group, in the epoxy resin.

[0029] The bifunctional epoxy resin used in the present invention is an epoxy resin represented by the above formula (4), and examples include epoxy resins obtained by reacting a bifunctional phenol compound represented by HO-Y-OH with an epihalohydrin in the presence of an alkali metal compound. In the bifunctional phenol compound HO-Y-OH, Y is the same as Y in the above formula (4).

[0030] The raw epoxy resin represented by formula (4) preferably has an epoxy equivalent of 100 to 400 g / eq., more preferably 100 to 250 g / eq.

[0031] Examples of epihalohydrins include epichlorohydrin and epibromohydrin. Examples of alkali metal compounds include alkali metal hydroxides such as sodium hydroxide, lithium hydroxide, and potassium hydroxide; alkali metal salts such as sodium carbonate, sodium bicarbonate, sodium chloride, lithium chloride, and potassium chloride; alkali metal alkoxides such as sodium methoxide and sodium ethoxide; alkali metal salts of organic acids such as sodium acetate and sodium stearate; alkali metal phenoxides, sodium hydride, and lithium hydride. The amount used is 0.80 to 1.20 moles, preferably 0.85 to 1.05 moles, relative to the functional group (hydroxyl group) in the difunctional phenol compound. Using less than this may result in a large amount of residual hydrolyzable chlorine. The alkali metal compound is used in aqueous solution, alcohol solution, or solid state.

[0032] In the epoxidation reaction, an excess amount of epihalohydrin is used relative to the difunctional phenol compound. Typically, 1.5 to 15 moles of epihalohydrin are used per mole of functional groups in the difunctional phenol compound, but preferably 2 to 10 moles, and more preferably 5 to 8 moles. Using more than this tends to decrease production efficiency, while using less tends to increase the amount of high molecular weight epoxy resin produced.

[0033] The epoxidation reaction is usually carried out at a temperature of 120°C or lower. If the reaction temperature is too high, the amount of so-called poorly hydrolyzable chlorine increases, which can make it difficult to achieve high purity. Preferably, the temperature is 100°C or lower, and more preferably 85°C or lower.

[0034] In the resulting bifunctional epoxy resin of formula (4), the number of repetitions n is as described above. 2 n is the average value of the number of repetitions, and is between 0 and 6, preferably between 0 and 3, more preferably between 0 and 1, and even more preferably between 0 and 0.5. When the above bifunctional phenol compound is reacted with epihalohydrin, the number of repetitions in the resulting bifunctional epoxy resin of formula (4) is n 2 n is usually greater than 0. 2To achieve a value of 0, one can either highly purify an epoxy resin manufactured by a known method using techniques such as distillation or crystallization, or epoxidize the above-mentioned bifunctional phenol compound by allylation followed by oxidation of the olefin portion.

[0035] The difunctional epoxy resin represented by formula (4) used as a raw material is not limited as long as it has at least the aforementioned Y group, but examples include cyclohexanedimethanol diglycidyl ether, cyclohexanediol diglycidyl ether, isosorbide diglycidyl ether, isomannide diglycidyl ether, hydrogenated bisphenol A type epoxy resin, hydrogenated bisphenol F type epoxy resin, hydrogenated biphenol type epoxy resin, 2,4,8,10-tetraoxaspiro[5.5]undecane,3,9-bis[1,1-dimethyl-2(2-oxyranylmethoxy)ethyl], etc. The difunctional epoxy resin represented by formula (4) may be used in combination with other difunctional epoxy resins as long as it contains one of the above. Other bifunctional epoxy resins that may be used in combination include, but are not limited to, bisphenol-type epoxy resins such as bisphenol A-type epoxy resin, bisphenol F-type epoxy resin, bisphenolacetophenone-type epoxy resin, and diphenyl ether-type epoxy resin, as well as biphenol-type epoxy resins, diphenyldicyclopentadiene-type epoxy resin, alkylene glycol-type epoxy resin, and aliphatic cyclic epoxy resin. When using a bifunctional epoxy resin represented by formula (4) in combination with other bifunctional epoxy resins as a raw material, it is desirable to use the bifunctional epoxy resin represented by formula (4) in a proportion of preferably 10% by mass or more. More preferably 30% by mass or more, even more preferably 40% by mass or more, and even more preferably 50% by mass or more.

[0036] Number of repetitions n in equation (4) 2By using an epoxy resin with a repetition rate of 0 as a raw material, the modified epoxy resin of the present invention becomes free of secondary hydroxyl groups, and its viscosity and moisture resistance can be further improved. On the other hand, for example, when fine-tuning the adhesion to metal, an appropriate number of repetitions n greater than 0 can be used. 2 By using this epoxy resin, it is possible to intentionally include an appropriate amount of secondary hydroxyl groups in the modified epoxy resin of the present invention, within a range that does not significantly affect other physical properties such as viscosity and moisture resistance.

[0037] The reaction between the difunctional epoxy resin represented by general formula (4) and the diphenyl carbonate represented by formula (5) involves one molecule of diphenyl carbonate reacting with two epoxy groups (one epoxy resin molecule) of the difunctional epoxy resin, resulting in linear polycondensation. Therefore, the amount of raw materials used needs to be appropriately adjusted depending on the epoxy equivalent of the target modified epoxy resin, but it is desirable to use a ratio of 0.8 to 5 moles of epoxy resin of formula (4) per mole of diphenyl carbonate of formula (5), i.e., a difunctional epoxy resin / diphenyl carbonate (molar ratio) of 0.8 to 5. More preferably, the ratio is 0.9 to 4 moles of diphenyl carbonate and a difunctional epoxy resin / diphenyl carbonate (molar ratio) of 0.9 to 4. It is also possible to replace a part of the compound represented by general formula (5) with the above-mentioned difunctional phenol compound. As described above, by deliberately including an appropriate amount of secondary hydroxyl groups in the modified epoxy resin of the present invention, fine adjustments to solvent solubility, viscosity, adhesion, etc., can be made.

[0038] In the manufacturing method, it is preferable to use a catalyst, and the catalyst is preferably a compound in which the diphenyl carbonate of formula (5) has catalytic activity that preferentially reacts with the epoxy groups rather than the secondary hydroxyl groups of the epoxy resin. Basic compounds are preferred, and examples include tertiary amines, cyclic amines, imidazole compounds, organophosphorus compounds, and quaternary ammonium salts. Furthermore, these catalysts may be used individually or in combination of two or more.

[0039] The amount of catalyst used is usually 0.001 to 1% by mass of the reaction solids. However, when these compounds are used as catalysts, they may remain as residues in the resulting modified epoxy resin, potentially shortening the pot life of the composition. Therefore, the nitrogen content derived from the catalyst in the modified epoxy resin is preferably 0.5% by mass or less, and more preferably 0.3% by mass or less. Similarly, the phosphorus content derived from the catalyst in the modified epoxy resin is preferably 0.5% by mass or less, and more preferably 0.3% by mass or less.

[0040] In the manufacturing method of the present invention, a reaction solvent may be used, and any solvent that can dissolve the modified epoxy resin may be used. Examples include aromatic solvents, ketone solvents, amide solvents, glycol ether solvents, ester solvents, etc. Furthermore, these solvents may be used individually or in combination of two or more.

[0041] In the manufacturing method, the solid content concentration during the reaction is preferably 35 to 100% by mass. More preferably 50 to 100% by mass, and even more preferably 70 to 100% by mass. If a highly viscous product is formed during the reaction, additional solvent can be added to continue the reaction. After the reaction is complete, the solvent can be removed or added as needed.

[0042] The reaction temperature should be within a range that does not decompose the catalyst used. If the reaction temperature is too high, the catalyst may decompose, stopping the reaction or degrading the resulting modified epoxy resin. If the reaction temperature is too low, the reaction may not proceed sufficiently, and the desired molecular weight may not be achieved. Therefore, the reaction temperature is preferably 50 to 230°C, more preferably 70 to 210°C, even more preferably 90 to 200°C, and particularly preferably 100 to 180°C. The reaction time is usually 1 to 12 hours, preferably 3 to 10 hours. When using low-boiling point solvents such as acetone or methyl ethyl ketone, the reaction temperature can be ensured by carrying out the reaction under high pressure using an autoclave. If it is necessary to remove the heat of reaction, this is usually done by evaporation, condensation, reflux of the solvent using the heat of reaction, indirect cooling, or a combination of these methods.

[0043] The resin composition of the present invention is a resin composition comprising at least the modified epoxy resin of the present invention and a curing agent. Furthermore, the resin composition of the present invention may optionally contain other epoxy resins, inorganic fillers, coupling agents, antioxidants, and other additives as described later. The resin composition of the present invention provides a cured product that fully satisfies the various physical properties required for various applications.

[0044] In this invention, the term "curing agent" refers to a substance that contributes to the crosslinking reaction with the modified epoxy resin. Furthermore, in this invention, any substance that contributes to the crosslinking reaction of the epoxy resin, even if it is commonly referred to as a curing accelerator, will be considered a curing agent.

[0045] The curing agent content in the resin composition of the present invention is preferably 0.1 to 150 parts by mass of curing agent, more preferably 2 to 130 parts by mass, per 100 parts by mass of modified epoxy resin (or all epoxy resins, including other epoxy resins, if applicable). Note that this refers to the amount of non-volatile content (solids) in the resin composition.

[0046] In the resin composition of the present invention, if other epoxy resins are included, the modified epoxy resin of the present invention is preferably 1 to 99% by mass of the total epoxy resin, more preferably 50% by mass or more, and even more preferably 80% by mass or more. In this invention, "solid content" refers to the components excluding the solvent, and includes not only solid modified epoxy resins and other epoxy resins, but also semi-solid and viscous liquid substances. Furthermore, "resin component" refers to the sum of the modified epoxy resin of this invention and other epoxy resins.

[0047] There are no particular restrictions on the curing agent used in the resin composition of the present invention; all curing agents generally known for epoxy resins can be used. From the viewpoint of improving heat resistance, preferred curing agents include phenolic resins, amine compounds, amide compounds, imidazole compounds, and active ester curing agents and acid anhydride curing agents. These curing agents may be used individually or in combination of two or more types.

[0048] Other curing agents include, for example, acrylic ester resins, melamine resins, urea resins, cationic polymerizers, tertiary amines, organophosphines, phosphonium salts, tetraphenylboron salts, organic acid dihydrazides, boron-halogenated amine complexes, polymer captan curing agents, isocyanate compounds, polyisocyanate compounds, blocked isocyanate compounds, and carbodiimide compounds. These other curing agents may be used individually or mixed in any combination and ratio of two or more types.

[0049] The resin composition of the present invention may contain epoxy resins other than the modified epoxy resin of the present invention. By using other epoxy resins, it is possible to compensate for deficient physical properties or improve various physical properties. Preferably, the epoxy resin has two or more epoxy groups in its molecule, and more preferably, an epoxy resin has three or more epoxy groups. Examples include polyglycidyl ether compounds, polyglycidylamine compounds, polyglycidyl ester compounds, alicyclic epoxy compounds, and other modified epoxy resins. These epoxy resins may be used alone, two or more epoxy resins of the same system may be used in combination, or epoxy resins of different systems may be used in combination.

[0050] The resin composition of the present invention may contain a solvent or reactive diluent to appropriately adjust the viscosity of the resin composition during handling when forming a coating film. In the resin composition of the present invention, the solvent or reactive diluent is used to ensure the handling and workability of the resin composition during molding, and there are no particular restrictions on the amount used. In the present invention, the terms "solvent" and "solvent" are used to distinguish them according to their form of use, but the same type or different types may be used independently for each.

[0051] Examples of solvents that may be included in the resin composition of the present invention include ketones such as acetone, methyl ethyl ketone (MEK), methyl isobutyl ketone, and cyclohexanone; esters such as ethyl acetate; ethers such as ethylene glycol monomethyl ether; amides such as N,N-dimethylformamide and N,N-dimethylacetamide; alcohols such as methanol and ethanol; alkanes such as hexane and cyclohexane; and aromatics such as toluene and xylene. The solvents listed above may be used individually or mixed in any combination and ratio of two or more.

[0052] Examples of reactive diluents include monofunctional glycidyl ethers such as allyl glycidyl ether, bifunctional glycidyl ethers such as propylene glycol diglycidyl ether, polyfunctional glycidyl ethers such as trimethylolpropane polyglycidyl ether, glycidyl esters, and glycidylamines.

[0053] These solvents or reactive diluents are preferably used in an amount of 90% by mass or less, particularly in the range of 20 to 80% by mass, as non-volatile content, and the appropriate type and amount are selected as appropriate depending on the application. For example, in printed circuit board applications, polar solvents with a boiling point of 160°C or less, such as methyl ethyl ketone, acetone, and 1-methoxy-2-propanol, are preferred, and the amount used is preferably 40 to 80% by mass, as non-volatile content. In adhesive film applications, for example, ketones, acetate esters, carbitols, aromatic hydrocarbons, dimethylformamide, dimethylacetamide, and N-methylpyrrolidone are preferred, and the amount used is preferably 30 to 60% by mass, as non-volatile content.

[0054] The resin composition of the present invention may optionally contain a curing accelerator or a catalyst. Examples of curing accelerators or catalysts include imidazole compounds, tertiary amines, phosphorus compounds such as phosphines, metal compounds, Lewis acids, and amine complex salts. These may be used individually or in combination of two or more.

[0055] The amount of curing accelerator or catalyst added can be appropriately selected depending on the intended use, but 0.01 to 15 parts by mass are used as needed, per 100 parts by mass of the epoxy resin component in the resin composition (all epoxy resin components including the modified epoxy resin of the present invention). Preferably, it is 0.01 to 10 parts by mass, more preferably 0.05 to 8 parts by mass, even more preferably 0.1 to 5 parts by mass, and particularly preferably 0.1 to 1.0 part by mass. By using a curing accelerator or catalyst, the curing temperature can be lowered and the curing time can be shortened.

[0056] The resin composition of the present invention may use various known flame retardants to improve the flame retardancy of the resulting cured product, provided that reliability is not compromised. Examples of usable flame retardants include halogen-based flame retardants, phosphorus-based flame retardants, nitrogen-based flame retardants, silicone-based flame retardants, inorganic flame retardants, and organometallic salt-based flame retardants. From an environmental standpoint, halogen-free flame retardants are preferred, and phosphorus-based flame retardants are particularly preferred. These flame retardants may be used individually, in combination of two or more flame retardants of the same system, or in combination of flame retardants of different systems.

[0057] The resin composition of the present invention may contain components other than those described above for the purpose of further improving its functionality. Examples of such other components include fillers, thermoplastic resins, thermosetting resins, photocurable resins, UV inhibitors, antioxidants, coupling agents, plasticizers, fluxes, thixotropy-imparting agents, smoothing agents, colorants, pigments, dispersants, emulsifiers, de-elasticizing agents, mold release agents, defoaming agents, ion trapping agents, and the like.

[0058] The resin composition of the present invention is obtained by uniformly mixing the above components. The resin composition, which contains a modified epoxy resin, a curing agent, and optionally various other components, can be easily cured in the same manner as conventionally known methods. This cured product exhibits excellent decomposability and mechanical properties, and good cured physical properties. Curing, as used herein, means intentionally curing the resin composition with heat and / or light, and the degree of curing can be controlled according to the desired physical properties and application. The degree of curing can be fully cured or partially cured, and is not particularly limited, but the reaction rate of the curing reaction between the epoxy group and the curing agent is usually 5 to 95%.

[0059] The resin composition of the present invention can be cured in the same way as known epoxy resin compositions to obtain a cured product. Methods for obtaining a cured product can be the same as those for known epoxy resin compositions, and are preferably performed using methods such as casting, injection, potting, dipping, drip coating, transfer molding, compression molding, or lamination in the form of resin sheets, resin-coated copper foil, or prepregs, followed by heating, pressing, and curing to form laminates. The curing temperature is typically in the range of 80 to 300°C, and the curing time is typically about 10 to 500 minutes. For example, this heating is preferably performed in two stages: primary heating at 80 to 180°C for 10 to 150 minutes, and secondary heating at 120 to 200°C for 60 to 300 minutes. Furthermore, in formulations where the glass transition temperature (Tg) exceeds the secondary heating temperature, it is preferable to perform a tertiary heating at 150 to 280°C for 60 to 120 minutes. Such secondary and tertiary heating can reduce curing defects. When producing resin semi-cured products such as resin sheets, resin-coated copper foil, and prepregs, the curing reaction of the resin composition is usually advanced by heating or other means to the extent that the shape can be maintained. If the resin composition contains a solvent, most of the solvent is usually removed by methods such as heating, reduced pressure, or air drying, but it is also acceptable to leave a solvent content of 5% by mass or less in the resin semi-cured product.

[0060] The present invention describes a prepreg obtained using the resin composition of the present invention. The prepreg of the present invention consists of the resin composition or a semi-cured product thereof and a fibrous substrate. As the fibrous substrate, inorganic fibers such as carbon fibers and glass, or woven or nonwoven fabrics of organic fibers such as polyester, polyamine, polyacrylic, polyimide, Kevlar, and cellulose can be used, but are not limited thereto. The method for producing the prepreg from the resin composition and fibrous substrate of the present invention is not particularly limited. For example, the substrate may be impregnated by immersing it in a resin varnish obtained by adjusting the viscosity of the resin composition with a solvent, and then heated and dried to semi-cure (B-stage) the resin component. For example, it can be heated and dried at 100 to 200°C for 1 to 40 minutes. Here, the amount of resin in the prepreg is preferably 30 to 80% by mass.

[0061] The present invention describes a resin sheet obtained using the resin composition of the present invention. The resin sheet of the present invention consists of the resin composition or a semi-cured product thereof and a support film. As the support film, polyolefins such as polyethylene, polypropylene, and polyvinyl chloride, polyesters such as polyethylene terephthalate (PET) and polyethylene naphthalate, polycarbonate, polyimide, and even release paper, copper foil, aluminum foil, and other metal foils can be used, but are not limited thereto. The thickness of the support film is not particularly limited, but is usually 10 to 150 μm, and preferably used in the range of 25 to 50 μm. The method for producing the resin sheet from the resin composition and support film of the present invention is not particularly limited, and for example, one method is to apply the above-mentioned resin composition to the support film in a resin varnish whose viscosity has been adjusted with an aromatic or ketone-based solvent, and then dry it. The resin sheet is obtained by heating and drying to semi-cure (B-stage) the resin component, and can be heated and dried, for example, at 100 to 200°C for 1 to 40 minutes. Here, the amount of resin in the resin sheet is preferably 30 to 80% by mass. Furthermore, the thickness of the resin component is not particularly limited, but is in the range of 3 to 200 μm, more preferably 5 to 105 μm. The coating can be repeated multiple times as needed, and in this process, it is also possible to repeat the coating using multiple solutions with different compositions and concentrations to finally adjust to the desired resin composition and amount.

[0062] This invention describes a method for manufacturing laminates using prepregs and resin sheets. When forming a laminate using a prepreg, for example, one or more prepregs are laminated together, and metal foil is placed on one or both sides to form a laminate. This laminate is then heated and pressurized to integrate it. Here, single, alloy, or composite metal foils of copper, aluminum, brass, nickel, etc., can be used as the metal foil. The conditions for heating and pressurizing the laminate should be adjusted appropriately to the conditions under which the resin composition hardens. If the pressurization pressure is too low, air bubbles may remain inside the resulting laminate, potentially reducing its electrical properties. Therefore, it is desirable to pressurize under conditions that satisfy moldability. For example, a temperature of 160-220°C and a pressure of 49-490 N / cm². 2 (5~50kgf / cm 2 The heating time can be set to 10 to 240 minutes. Resin sheets can also be used instead of prepreg.

[0063] Furthermore, a multilayer board can be created using the single-layer laminate obtained in this way as an inner layer material. In this case, first, circuits are formed on the laminate using an additive method or a subtractive method, and the formed circuit surface is treated with an acid solution to blacken it and obtain the inner layer material. An insulating layer is formed on one or both sides of the circuit-formed surface of this inner layer material using prepreg or a resin sheet, and a conductive layer is formed on the surface of the insulating layer to form a multilayer board.

[0064] When forming an insulating layer with a resin sheet, a laminate is formed by placing resin sheets on the circuit-forming surfaces of multiple inner layer materials. Alternatively, a laminate is formed by placing a resin sheet between the circuit-forming surface of the inner layer material and the metal foil. This laminate is then heated and pressurized to form a single unit, thereby forming a hardened resin sheet as the insulating layer and creating a multilayer structure of the inner layer material. Alternatively, the inner layer material and the metal foil, which acts as the conductive layer, are formed with the hardened resin sheet as the insulating layer. Here, the metal foil can be the same type used for the laminate used as the inner layer material. Furthermore, heat and pressure molding can be carried out under the same conditions as for molding the inner layer material. When forming an insulating layer by applying a resin composition to a laminate, the outermost circuit-forming surface resin of the inner layer material is coated with the above resin composition to a thickness of preferably 5 to 100 μm, and then heated and dried at 100 to 200°C for 1 to 90 minutes to form a sheet. This is generally formed by a method called the casting method. It is desirable to form the thickness after drying to 5 to 80 μm. On the surface of the multilayer laminate formed in this way, via holes and circuits can be formed using the additive method or the subtractive method to form a printed wiring board. Furthermore, by repeating the above process using this printed circuit board as an inner layer material, it is possible to form even more layers of laminated boards.

[0065] Furthermore, when forming an insulating layer with prepreg, one or more layers of prepreg are laminated and placed on the circuit-forming surface of the inner layer material, and metal foil is placed on the outside of that to form a laminate. This laminate is then heated and pressurized to form a single unit, thereby forming the cured prepreg as the insulating layer and the outer metal foil as the conductive layer. Here, the same type of metal foil used for the laminated board used as the inner layer material can be used. Furthermore, the heat and pressure molding can be carried out under the same conditions as for molding the inner layer material. On the surface of the multilayer laminated board formed in this way, via holes and circuits can be formed using additive or subtractive methods to create a printed circuit board. Furthermore, by repeating the above process using this printed circuit board as an inner layer material, it is possible to form even more multilayer boards.

[0066] Furthermore, when the resin sheet of the present invention is used as a bonding sheet, for example, two substrates can be bonded together with the resin sheet. Each of the two substrates is, for example, a laminate or a printed circuit board. Specifically, for example, the resin sheet is produced by forming an epoxy resin composition into a sheet shape on a support film by a coating method or the like, and then drying or semi-curing it by heating. This resin sheet is placed on a substrate (first substrate), the support film is peeled off the resin sheet, and another substrate (second substrate) is placed on top. That is, the first substrate, the resin sheet (epoxy resin composition), and the second substrate are laminated in that order. Subsequently, by heating and curing, the first substrate and the second substrate are bonded together via the cured epoxy resin composition.

[0067] The fiber-reinforced composite material of the present invention can be obtained by impregnating reinforcing fibers with the resin composition of the present invention to obtain a fiber-reinforced composite material composition, and then molding and curing it. Here, the reinforcing fibers may be twisted yarn, untwisted yarn, or untwisted yarn, but untwisted yarn and untwisted yarn are preferred because they have excellent moldability in the fiber-reinforced composite material. Furthermore, the form of the reinforcing fibers can be those with the fiber direction aligned in one direction, or woven fabric can be used. In the case of woven fabric, plain weave, satin weave, etc. can be freely selected depending on the part and application in which it will be used. Specifically, carbon fibers, glass fibers, aramid fibers, boron fibers, alumina fibers, silicon carbide fibers, etc., can be used because they have excellent mechanical strength and durability, and these can be used alone or in combination of two or more types. Among these, carbon fibers are particularly preferred because they result in good strength of the molded product, and various types of carbon fibers such as polyacrylonitrile, pitch, and rayon can be used.

[0068] The method for obtaining a fiber-reinforced composite material from the resin composition of the present invention is not particularly limited, but examples include: uniformly mixing each component constituting the resin composition to produce a varnish, and using it as a prepreg, for example, impregnating a material such as a sheet of continuous carbon fibers arranged in one direction or a carbon fiber fabric with resin, or arranging a resin layer on at least one surface of a carbon fiber substrate, or arranging a fiber layer on the said surface, or immersing unidirectional reinforcing fibers, in which reinforcing fibers are aligned in one direction, into the varnish obtained above (pre-curing state in the pull extraction method or filament winding method, tow prepreg), or stacking sheets or fabrics of reinforcing fibers and setting them in a mold, then injecting resin into the mold and impregnating under pressure or by reducing the pressure inside (pre-curing state in the RTM method).

[0069] In the fiber-reinforced composite material of the present invention, the volume content of reinforcing fibers relative to the total volume of the molded product is preferably 40% to 85%, and more preferably in the range of 50% to 75% from the viewpoint of strength. If the volume content is less than 40%, the content of the resin composition is too high, which may result in insufficient elastic modulus and strength of the resulting cured product, or it may not be able to meet the required properties. If the volume content exceeds 85%, there may be insufficient resin in the reinforcing fibers, leading to insufficient adhesion and void formation, which may result in insufficient elastic modulus and strength of the cured product, or a decrease in interfacial adhesion.

[0070] The cured products, laminates, and fiber-reinforced composite materials obtained from the resin composition of the present invention have excellent decomposability and mechanical properties.

[0071] The decomposition method of the present invention involves reacting the cured product, laminate, or fiber-reinforced composite material obtained above with a primary amine. It is believed that the decomposition is promoted by the depolymerization of the carbonate structure of the cured product, etc., through the use of a primary amine. It is believed that the presence of alicyclic hydrocarbon groups results in a lower molecular weight than general-purpose epoxy resins, and therefore the concentration of the carbonate structure in the cured product involved in decomposition increases, making it easier to decompose.

[0072] In the decomposition method of the present invention, any primary amine may be used. Examples include methylamine, ethylamine, propylamine, butylamine, pentylamine, hexylamine, heptylamine, octylamine, nonylamine, ethylenediamine, hexamethylenediamine, spermidine, spermine, amantadine, aniline, toluidine, benzidine, catecholamine, phenethylamine, and the like. These compounds may be used individually or in combination of two or more.

[0073] In the decomposition method, the reaction temperature is preferably 50 to 230°C, more preferably 70 to 200°C, and even more preferably 90 to 180°C. The reaction time is usually 0 to 24 hours, preferably 0 to 10 hours, and more preferably 0 to 4 hours. [Examples]

[0074] The present invention will be further described below with reference to examples and comparative examples, but it is not limited to these. Unless otherwise specified, "parts" refers to parts by mass, and "%" refers to mass percent. The analytical and measurement methods are shown below. All units for all equivalents are "g / eq."

[0075] (1) GPC chart (Mw): The results were obtained by GPC measurement. Specifically, a Tosoh Corporation HLC8320GPC was used, with columns (TSKgel SuperH-H, SuperH2000, SuperHM-H, SuperHM-H, all manufactured by Tosoh Corporation) connected in series, and the column temperature was set to 40°C. Tetrahydrofuran (THF) was used as the eluent at a flow rate of 1.0 mL / min, and a differential refractive index detector was used. For the measurement sample, 0.1 g of solid content was dissolved in 10 mL of THF, filtered through a 0.45 μm microfilter, and 50 μL of the resulting sample was used. Calibration curves were created using standard polystyrene (Tosoh Corporation, PStQuick A, PStQuick B, PStQuick C). Data processing was performed using Tosoh Corporation's GPC8020 Model II version 6.00. (2) IR (Infrared Absorption Spectrum): Using a Fourier transform infrared spectrophotometer (Perkin Elmer Precisely, Spectrum One FT-IR Spectrometer 1760X), sodium chloride was used as the cell. The sample, dissolved in chloroform, was coated onto the cell, dried, and then measured at wavenumbers of 500-4000 cm⁻¹. -1 The transmittance was measured. (3) Epoxy equivalent: Measurements were performed in accordance with JIS K7236. Specifically, a potentiometric titrator was used, chloroform was used as the solvent, tetraethylammonium brominated acetate solution was added, and a 0.1 mol / L perchloric acid-acetic acid solution was used. (4) Melt viscosity: The viscosity at 150°C was measured using an ICI viscometer (CV-1S, manufactured by Toa Kogyo Co., Ltd.). (5) Flexural modulus: Measurements were taken using the three-point bending test (Method A) in accordance with the JIS K7074 standard. A Shimadzu Autograph AGS-X testing machine was used, and the sample dimensions were 2 mm thick, 100 mm long, and 15 mm wide. The test was conducted at a test speed of 2 mm / min. (6) Disassembly time: In a four-necked glass separable flask equipped with a stirrer, thermometer, condenser, and nitrogen gas introduction device, 100 parts of a hardened material measuring 2 mm thick, 1 cm long, and 1 cm wide, and 4000 parts of 1-hexylamine were charged at room temperature. Nitrogen gas was introduced, and the temperature was raised to 125°C while stirring. Stirring continued, and the time until the hardened material disappeared was evaluated visually. ◎: Disassembled in 4 hours or less ○: Decomposed in 4 hours or more but less than 10 hours. ×: Products that do not decompose in 10 hours, or leave behind decomposition residue.

[0076] The abbreviations used in the examples and comparative examples are as follows: [Bifunctional epoxy resin] A1: 1,4-Cyclohexanedimethanol diglycidyl ether (manufactured by Nippon Steel Chemical & Material Co., Ltd., ZX-1658GS, epoxy equivalent 132) [ka] A2: Isosorbide diglycidyl ether (compound obtained in Synthesis Example 1, epoxy equivalent 157) [ka] A3: Bisphenol A type liquid epoxy resin (manufactured by Nippon Steel Chemical & Material Co., Ltd., YD-128, epoxy equivalent weight 186) [ka] A4: Bisphenol A type liquid epoxy resin (manufactured by Nippon Steel Chemical & Material Co., Ltd., mixture of YD-011 and YD-128 (mixing ratio: YD-011:YD-128=90:10), epoxy equivalent 420) [ka]

[0077] [Carbonate ester compounds] B1: Diphenyl carbonate (manufactured by Tokyo Chemical Industry Co., Ltd., molecular weight 214, activity equivalent 107) [ka]

[0078] [Hardening agent] C1: 4-Methylhexahydrophthalic anhydride (manufactured by Shin-Nippon Rika Co., Ltd., Ricacid MH-T, active hydrogen equivalent 168) [ka]

[0079] [catalyst] D1: 4-Dimethylaminopyridine (manufactured by Fujifilm Wako Pure Chemical Industries, Ltd.) [ka] D2: 2-Ethyl-4-methylimidazole (manufactured by Shikoku Chemicals Co., Ltd., 2E4MZ) [ka]

[0080] Synthesis Example 1 In a glass separable flask equipped with a stirrer, thermometer, nitrogen inlet tube, reflux condenser with oil-water separator, and vacuum device, 100 parts of isosorbide (manufactured by Tokyo Chemical Industry Co., Ltd.) and 633 parts of epichlorohydrin were charged and heated to 63°C under a nitrogen atmosphere while stirring. Eleven parts of 50% sodium hydroxide aqueous solution were added quantitatively over 2 hours. Next, while maintaining the temperature in the reaction system at 65°C, the pressure was gradually reduced to reflux the epichlorohydrin. 109 parts of 50% sodium hydroxide aqueous solution were added dropwise continuously over 2 hours. During this time, the pressure was reduced to 120 Torr, and the azeotrope of water and epichlorohydrin was separated into two layers using the oil-water separator. The lower layer of epichlorohydrin was returned to the system, and the upper layer of water was removed from the system. After the reaction, the pressure and temperature were gradually increased until the epichlorohydrin was removed by distillation at 150°C and 5 Torr. Subsequently, the reaction system was returned to atmospheric pressure, 300 parts of toluene were added and dissolved, and 500 parts of water were added to separate and remove the by-product sodium chloride. Then, the mixture was washed repeatedly with 300 parts of water until the washing water became neutral. The solution was heated to 150°C under reduced pressure of 5 Torr to remove toluene and obtain liquid epoxy resin (A2). The epoxy equivalent of the obtained liquid epoxy resin (A2) was 157 g / eq.

[0081] Example 1 In a four-necked glass separable flask equipped with a stirrer, thermometer, condenser, and nitrogen gas introduction device, 100 parts of 1,4-cyclohexanedimethanol diglycidyl ether (A1) as the epoxy resin and 44 parts of diphenyl carbonate (B1) as the carbonate ester compound were charged at room temperature. The mixture was heated to 125°C while stirring and nitrogen gas was introduced. After adding 0.007 parts of catalyst (D1), the temperature was raised to 145°C, and the reaction was carried out at the same temperature until there was no change in epoxy equivalent, yielding the modified epoxy resin (R1). In Table 1, "carbonate concentration" represents the molar amount of diphenyl carbonate per 100g of solids after charging. The Mw, epoxy equivalent, and melt viscosity of the obtained modified epoxy resin (R1) were measured. The results are shown in Table 1. Figure 1 shows the GPC chart, and Figure 2 shows the IR chart.

[0082] Examples 2-12, Comparative Examples 1, 2 According to the amount (parts) of each raw material shown in Table 1, the same procedure as in Example 1 was performed to obtain resins for Examples 2-12 (R2-R12) and resins for Comparative Examples 1 and 2 (HR1, HR2). The epoxy equivalent and melt viscosity of R2-R12 and HR1, HR2 were measured. The results are shown in Table 1.

[0083] [Table 1]

[0084] Example 13 100 parts of the modified epoxy resin (R1) obtained in Example 1 were used as the epoxy resin, 40 parts of 4-methylhexahydrophthalic anhydride (C1) as a curing agent, and 0.2 parts of 2-ethyl-4-methylimidazole (D2) as a curing accelerator were mixed and stirred for 5 minutes under vacuum degassing using a rotation / revolution laboratory vacuum planetary mixer to obtain a liquid resin composition. Next, this liquid resin composition was poured into a 2 mm thick mold that had been preheated to 100°C, and then placed in a hot air oven and heated and cured at 100°C for 2 hours and then at 150°C for 5 hours to obtain a cured product. The flexural modulus and decomposition time were measured by cutting the obtained cured product into sizes suitable for each measurement. The results are shown in Table 2.

[0085] Examples 14-24, Comparative Examples 3 and 4 According to the amount (parts) of each raw material shown in Table 2, the same procedure as in Example 13 was performed to obtain cured products for Examples 14-24 and Comparative Examples 3 and 4. The flexural modulus and decomposition time were measured by cutting the obtained cured products to a size suitable for each measurement. The results are shown in Table 2.

[0086] [Table 2]

[0087] As can be seen from Table 1, the modified epoxy resins of the present invention shown in Examples 1 to 12 have low viscosity while maintaining or increasing the carbonate concentration, which is related to the decomposition time. Furthermore, as can be seen from Table 2, the cured products of the modified epoxy resins of the present invention shown in Examples 13 to 24 have excellent mechanical properties and decomposition properties.

Claims

1. A modified epoxy resin characterized by being represented by the following general formula (1). 【Chemistry 1】 Here, X is a monovalent group represented by formula (2-1) or formula (2-2) above, and formulas (2-1) and (2-2) may be present together in a single molecule. Y is a divalent group and has at least an alicyclic hydrocarbon group which may have a heteroatom. １ n is the average number of repetitions, and is between 0 and 500 (inclusive). １ If n is 0, then X has at least one of the bases represented by equation (2-2). ２ This is the average value of the number of repetitions, and is between 0 and 6 (inclusive).

2. The modified epoxy resin according to claim 1, wherein Y is a divalent group and has at least 10% by mass of an alicyclic hydrocarbon group having 1 to 15 carbon atoms, which may have an oxygen atom.

3. The modified epoxy resin according to claim 2, wherein Y is a divalent group and has at least 10% by mass of a divalent group represented by the following formula (3-1) and / or the following formula (3-2). 【Chemistry 2】

4. A resin composition characterized by comprising the modified epoxy resin described in claim 1 and a curing agent.

5. A cured product obtained by curing the resin composition according to claim 4.

6. A prepreg comprising the resin composition or semi-cured product thereof according to claim 4 and a fibrous substrate.

7. A resin sheet comprising the resin composition or semi-cured product thereof according to claim 4 and a support film.

8. A laminated board formed by laminating the prepreg described in claim 6 and / or the resin sheet described in claim 7.

9. A resin composition for fiber-reinforced composite materials, characterized by impregnating reinforcing fibers with the resin composition described in claim 4.

10. A fiber-reinforced composite material obtained from the resin composition for fiber-reinforced composite materials according to claim 9.

11. A method for producing the modified epoxy resin described in claim 1, A method for producing a modified epoxy resin, characterized by reacting a bifunctional epoxy resin represented by the following general formula (4) with a diphenyl carbonate represented by the following formula (5). 【Transformation 3】 Here, Y, n ２ This is equivalent to general formula (1). G is a monovalent group represented by the above formula (2-1).

12. A method for decomposing a cured product or a fiber-reinforced composite material, characterized by reacting the cured product described in claim 5 or the fiber-reinforced composite material described in claim 10 with a primary amine.

13. A method for decomposing a laminate, characterized by reacting the laminate described in claim 8 with a primary amine.

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