Modified epoxy resin, resin composition, cured product, prepreg, resin sheet, and laminated board

Abstract

To provide an epoxy resin composition and a cured product thereof, which include a modified epoxy resin as an essential component and which exhibit excellent low dielectric properties.SOLUTION: A modified epoxy resin is obtained by reacting a bifunctional epoxy resin represented by the general formula (4) in the figure with a diphenyl carbonate represented by the formula (5) in the figure. The modified epoxy resin has a weight-average molecular weight of 500 to 100,000. In the formulas, Y represents a divalent group, G represents a glycidyl group, and n2 is from 0 to 6 inclusive.SELECTED DRAWING: None

Description

[Technical Field]

[0001] The present invention relates to a modified epoxy resin having low water absorption and dielectric loss tangent, and also to an epoxy resin composition containing the modified epoxy resin as an essential component, and a cured product thereof. [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. Furthermore, film-forming properties can be imparted by increasing their molecular weight through various methods. Such high-molecular-weight epoxy resins are called phenoxy resins. Bisphenol A-type phenoxy resins, in particular, are primarily used as base resins for paint varnishes and film molding, and are added to epoxy resin varnishes to adjust flowability and improve toughness and adhesion when cured.

[0003] In recent years, information devices have become increasingly smaller and more powerful. As a result, higher performance is being demanded of the epoxy resins used in the fields of semiconductors and electronic components. In particular, low dielectric properties are being required to accompany thinner and more highly functional substrates.

[0004] In response to such demands, for example, Patent Document 1 discloses an epoxy resin obtained by reacting a difunctional epoxy resin each containing a bisphenyl structure with a diester compound, and a cured product thereof. However, there is still room for further improvement in response to the demand for low dielectric properties based on recent trends toward higher functionality. Patent Document 2 discloses a bisepoxy compound-diphenyl carbonate polyaddition copolymer, and Patent Document 3 discloses a method of providing a specific aromatic carbonate group-containing structure and an epoxy group-containing structure, mixing the two structures, and then obtaining a carbonate-containing epoxy resin under the action of a catalyst. However, Patent Documents 2 and 3 only discuss bisphenol A epoxy resin, ethylene glycol diglycidyl ether, biphenyl diglycidyl ether, and tetramethylbiphenyl diglycidyl ether as bisepoxy compounds or epoxy group-containing structures, and do not consider dielectric properties at all. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] Japanese Patent Application Laid-Open No. 2016-089165 [Patent Document 2] Japanese Patent Application Publication No. 11-302369 [Patent Document 3] Japanese Patent Application Publication No. 2023-48991 Summary of the Invention [Problem to be solved by the invention]

[0006] Therefore, an object of the present invention is to provide a modified epoxy resin having excellent low dielectric properties and useful for applications such as lamination, molding, casting, and adhesion, a resin composition thereof, and a cured product thereof. [Means for solving the problem]

[0007] In order to solve the above problems, the present inventors have conducted extensive research into various structures of bifunctional epoxy resins and have found that a cured product obtained by curing a resin composition containing a modified epoxy resin having a specific structure has excellent dielectric properties, thereby completing the present invention.

[0008] That is, the present invention relates to a modified epoxy resin represented by the following general formula (1) and characterized in that the weight average molecular weight is 500 to 100,000. [ka] Here, X is a monovalent group represented by the above formula (2-1) or (2-2), and the above formula (2-1) and the above formula (2-2) may be mixed in one molecule. Y is a divalent group and has at least a divalent group represented by the above formula (3). R 1 are independently selected from alkyl groups having 1 to 12 carbon atoms, alkoxy groups having 1 to 12 carbon atoms, aryl groups having 6 to 12 carbon atoms, alkenyl groups having 2 to 12 carbon atoms, and alkynyl groups having 2 to 12 carbon atoms. m is 1 or more and 4 or less. n 1 is the average number of repetitions, and is between 0 and 500. 1 When n is 0, X has at least a group represented by the above formula (2-2). 2 is the average number of repetitions, and is between 0 and 6.

[0009] In formula (1), Y is a divalent group, and it is preferable that the divalent group represented by formula (3) is present in an amount of at least 5% by mass. 1 are independently selected from alkyl groups having 4 or more carbon atoms and aryl groups having 6 to 12 carbon atoms, and m is preferably 1 or more and 2 or less.

[0010] The present invention also provides a resin composition containing the above-mentioned modified epoxy resin and a curing agent.

[0011] The present invention also relates to a cured product obtained by curing the resin composition, a prepreg comprising the resin composition or a semi-cured product thereof and a fibrous substrate, and a resin sheet comprising the resin composition or a semi-cured product thereof and a support film.The present invention also relates to a laminate formed by laminating the prepreg and / or the resin sheet.

[0012] The present invention also provides a method for producing the above-mentioned 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). [ka] Here, Y has the same meaning as in general formula (1). G is a monovalent group represented by the above formula (2-1). n 2 is the average number of repetitions, and is between 0 and 6. [Effects of the Invention]

[0013] The present invention provides a modified epoxy resin and resin composition having excellent dielectric properties. The modified epoxy resin has excellent dielectric properties and can be suitably used in applications requiring low dielectric constant and low dielectric dissipation factor, such as multilayer printed wiring boards, laminates for electric and electronic circuits (e.g., capacitors), adhesives (e.g., film adhesives, liquid adhesives), semiconductor encapsulation materials, underfill materials, interchip fill materials for 3D-LSIs, insulating sheets, prepregs, and heat dissipation substrates. [Brief explanation of the drawings]

[0014] [Figure 1] 1 is a GPC chart of the modified epoxy resin of Example 1. [Figure 2] 1 is an IR chart of the modified epoxy resin of Example 1. DETAILED DESCRIPTION OF THE INVENTION

[0015] Hereinafter, embodiments of the present invention will be described in detail. However, the present invention is not limited to the following embodiments and examples, and can be implemented with any modifications within the scope of the claims of the present invention and their equivalents.

[0016] The modified epoxy resin of the present invention is represented by general formula (1) and characterized by having a weight-average molecular weight of 500 to 100,000, and has a structure represented by formula (2-1) or formula (2-2). Formula (2-1) and formula (2-2) may be mixed in one molecule. Furthermore, the modified epoxy resin has at least a divalent group represented by formula (3). [ka]

[0017] The weight-average molecular weight (Mw) of the modified epoxy resin of the present invention is preferably 500 or more and 100,000 or less. Here, an Mw of less than 500 is undesirable because it may result in less introduction of a structure that improves dielectric properties. An Mw of more than 100,000 is undesirable because it may result in reduced compatibility or difficulty in handling the resin. Furthermore, from the viewpoint of improving the film-forming properties of the modified epoxy resin, Mw is preferably 5,000 or more, more preferably 10,000 or more, and even more preferably 15,000 or more. From the viewpoint of improving compatibility and handleability, Mw is more preferably 160,000 or less, even more preferably 120,000 or less, and particularly preferably 80,000 or less. For substrate applications where the resin is used by impregnation into a substrate, Mw may be 10,000 or less, more preferably 5,000 or less. The Mw of the modified epoxy resin can be measured by gel permeation chromatography (GPC) as described in the examples.

[0018] If the epoxy equivalent is 200 to 100,000 g / eq., the modified epoxy resin can participate in the curing reaction and be incorporated into a crosslinked structure. The epoxy equivalent is preferably 500 to 40,000, more preferably 600 to 30,000, and even more preferably 700 to 20,000. For film applications, where film-forming properties are required, a higher epoxy equivalent is desirable, such as 5,000 to 50,000, more preferably 10,000 to 50,000, and even more preferably 20,000 to 50,000. On the other hand, for substrate applications where the resin is impregnated into a substrate, good impregnation properties are required, so a lower epoxy equivalent is desirable, such as 280 to 10,000, more preferably 280 to 5,000, and even more preferably 280 to 3,000.

[0019] In the above general formula (1), n 1 is the number of repetitions and is an average value. The value ranges from 0 to 500. From the viewpoint of moldability and handleability, it is preferably from 0 to 200, more preferably from 0 to 100, and even more preferably from 0 to 50. The number of repetitions n 1 can be calculated from the number average molecular weight (Mn) obtained by GPC. 1 When is 0, X has at least a group of the above formula (2-2).

[0020] In the above general formula (1), Y has at least a divalent group represented by the above formula (3).

[0021] In the above general formula (3), R 1 are independently selected from an alkyl group having 1 to 12 carbon atoms, an alkoxy group having 1 to 12 carbon atoms, an aryl group having 6 to 12 carbon atoms, an alkenyl group having 2 to 12 carbon atoms, and an alkynyl group having 2 to 12 carbon atoms.

[0022] The alkyl group having 1 to 12 carbon atoms may be linear, branched, or cyclic, and examples thereof include a methyl group, an ethyl group, an n-propyl group, an isopropyl group, an n-butyl group, a sec-butyl group, a t-butyl group, an n-pentyl group, an isopentyl group, a neopentyl group, a t-pentyl group, a cyclopentyl group, an n-hexyl group, an isohexyl group, a cyclohexyl group, an n-heptyl group, a cycloheptyl group, a methylcyclohexyl group, an n-octyl group, a cyclooctyl group, an n-nonyl group, a 3,3,5-trimethylcyclohexyl group, an n-decyl group, a cyclodecyl group, an n-undecyl group, an n-dodecyl group, a cyclododecyl group, a benzyl group, a methylbenzyl group, a dimethylbenzyl group, a trimethylbenzyl group, a naphthylmethyl group, a phenethyl group, and a 2-phenylisopropyl group. Examples of aryl groups having 6 to 12 carbon atoms include phenyl, tolyl, ethylphenyl, xylyl, n-propylphenyl, isopropylphenyl, mesityl, naphthyl, and methylnaphthyl groups. Examples of aralkyl groups having 7 to 12 carbon atoms include benzyl, methylbenzyl, dimethylbenzyl, trimethylbenzyl, phenethyl, 2-phenylisopropyl, and naphthylmethyl groups.

[0023] Examples of the alkoxy group having 1 to 12 carbon atoms include a methoxy group, an ethoxy group, an n-propoxy group, an isopropoxy group, an n-butoxy group, a sec-butoxy group, a t-butoxy group, an n-pentoxy group, an isopentoxy group, a neopentoxy group, a t-pentoxy group, a cyclopentoxy group, an n-hexyloxy group, an isohexyloxy group, a cyclohexyloxy group, an n-heptoxy group, a cycloheptoxy group, and a methylcyclohexyloxy group. , n-octyloxy group, cyclooctyloxy group, n-nonyloxy group, 3,3,5-trimethylcyclohexyloxy group, n-decyloxy group, cyclodecyloxy group, n-undecyloxy group, n-dodecyloxy group, cyclododecyloxy group, benzyloxy group, methylbenzyloxy group, dimethylbenzyloxy group, trimethylbenzyloxy group, naphthylmethoxy group, phenethyloxy group, 2-phenylisopropoxy group, and the like.

[0024] Examples of the aryl group having 6 to 12 carbon atoms include a phenyl group, an o-tolyl group, an m-tolyl group, a p-tolyl group, an ethylphenyl group, a styryl group, a xylyl group, an n-propylphenyl group, an isopropylphenyl group, a mesityl group, an ethynylphenyl group, a naphthyl group, and a methylnaphthyl group.

[0025] Examples of alkenyl groups having 2 to 12 carbon atoms include vinyl, 1-propenyl, 2-propenyl, 1-methylvinyl, 1-butenyl, 2-butenyl, 3-butenyl, 1,3-butadienyl, cyclohexenyl, cyclohexadienyl, cinnamyl, and naphthylvinyl groups.

[0026] Examples of the alkynyl group having 2 to 12 carbon atoms include an ethynyl group, a 1-propynyl group, a 2-propynyl group, a 1-butynyl group, a 2-butynyl group, a 3-butynyl group, a 1,3-butadienyl group, a phenylethynyl group, and a naphthylethynyl group.

[0027] In the above general formula (3), the value of m ranges from 1 to 4, preferably from 1 to 2.

[0028] In the general formula (1), Y may have a skeleton derived from the residual skeleton obtained by removing two glycidyloxy groups from a difunctional epoxy resin (diglycidyl ether compound). Examples of difunctional epoxy resins include bisphenol-type epoxy resins such as bisphenol A-type epoxy resins, bisphenol F-type epoxy resins, bisphenolacetophenone-type epoxy resins, and diphenyl ether-type epoxy resins, biphenol-type epoxy resins, diphenyldicyclopentadiene-type epoxy resins, alkylene glycol-type epoxy resins, and alicyclic epoxy resins. These epoxy resins may be substituted with a substituent. Calculated from the weight ratio of the raw materials, Y contains at least 5% by mass or more of a divalent group represented by formula (3). As a modified epoxy resin, the molar percentage is calculated to be approximately the same as the mass percentage. [ka] From the viewpoint of improving dielectric properties, the content of Y excluding the divalent group represented by formula (3) is preferably 95% by mass or less. Y preferably contains 50% by mass or more, and even more preferably 80% by mass, of the divalent group represented by formula (3). This allows the presence of an appropriate amount of a skeleton derived from a bifunctional epoxy resin in the modified epoxy resin of the present invention, allowing fine adjustment of solvent solubility, dielectric properties, moisture resistance, adhesion, viscosity, etc.

[0029] In general formula (1), the terminal group X is a monovalent group represented by formula (2-1) or formula (2-2), and both formulas (2-1) and (2-2) may be present in one molecule. Preferably, at least a group represented by formula (2-2) is present. In the raw material epoxy resin of general formula (4), all terminal groups are glycidyl groups of formula (2-1) represented as G. In the modified epoxy resin of general formula (1), when reacted with diphenyl carbonate and calculated from the weight ratio of the raw materials charged, preferably 5% by mass or more of the terminal groups are groups represented by formula (2-2). Of the terminal groups, groups represented by formula (2-2) are more preferably 20% by mass or more, and even more preferably 50% by mass or more. As a modified epoxy resin, the molar percentage is calculated to be similar to the mass percentage. [ka]

[0030] The modified epoxy resin of the present invention is one in which secondary hydroxyl groups are not increased in the structure during modification, and a preferred production method is a production method in which a bifunctional epoxy resin represented by general formula (4) is reacted with diphenyl carbonate represented by formula (5). [ka] In formula (4), Y is the same as in formula (1). G is a monovalent group represented by formula (2-1) above. 2 is the average number of repetitions, and is 0 to 6, preferably 0 to 3. In this production method, the reaction between the epoxy resin of formula (4) and diphenyl carbonate of formula (5) is considered to be a mechanism in which diphenyl carbonate dissociates into phenol and undergoes a polycondensation reaction with the epoxy group of the epoxy resin, rather than with the secondary hydroxyl group.

[0031] The bifunctional epoxy resin used in the present invention is an epoxy resin represented by the above formula (4), and examples thereof include an epoxy resin obtained by reacting a bifunctional phenol compound represented by HO-Y-OH with 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).

[0032] The starting epoxy resin represented by formula (4) preferably has an epoxy equivalent of 100 to 400 g / eq., more preferably 100 to 200 g / eq.

[0033] 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 times, preferably 0.85 to 1.05 times, the molar amount of the functional group (hydroxyl group) in the bifunctional phenol compound. Less than this amount may result in a large amount of residual hydrolyzable chlorine. The alkali metal compound is used in the form of an aqueous solution, an alcohol solution, or a solid.

[0034] In the epoxidation reaction, an excess amount of epihalohydrin is used relative to the bifunctional phenol compound. Typically, 1.5 to 15 moles of epihalohydrin are used per mole of functional groups in the bifunctional phenol compound, preferably 2 to 10 moles, and more preferably 5 to 8 moles. If the amount is greater than this, production efficiency decreases, and if it is less than this, the amount of high molecular weight epoxy resin produced increases, making it unsuitable as a raw material.

[0035] The epoxidation reaction is usually carried out at a temperature of 120°C or lower. If the reaction temperature is high, the amount of so-called difficultly hydrolyzable chlorine increases, making it difficult to achieve high purification. The temperature is preferably 100°C or lower, and more preferably 85°C or lower.

[0036] In the resulting bifunctional epoxy resin of formula (4), the repeating number n 2 is preferably 0 or more and 3 or less, more preferably 0 or more and 1 or less, and even more preferably 0 or more and 0.5 or less. When the bifunctional phenol compound is reacted with epihalohydrin, the repeating number n 2 is usually greater than 0. 2 In order to make the value of phenolic compound (difunctional phenol compound) zero, an epoxy resin produced by a known method can be highly purified by distillation, crystallization, or the like, or the bifunctional phenolic compound can be allylated and then epoxidized by oxidizing the olefin moiety.

[0037] Examples of the bifunctional epoxy resin represented by formula (4) used as a raw material include di-tert-butylhydroquinone diglycidyl ether and phenylhydroquinone diglycidyl ether. The bifunctional epoxy resin represented by formula (4) may be used in combination with other bifunctional epoxy resins, as long as it contains the bifunctional epoxy resin. Examples of 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 resins, bisphenol F-type epoxy resins, bisphenolacetophenone-type epoxy resins, and diphenyl ether-type epoxy resins, biphenol-type epoxy resins, diphenyldicyclopentadiene-type epoxy resins, alkylene glycol-type epoxy resins, and alicyclic epoxy resins. When the bifunctional epoxy resin represented by formula (4) is used 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 5% by mass or more, more preferably 50% by mass or more, and even more preferably 80% by mass or more.

[0038] The number of repetitions n in Eq. (4) 2 By using an epoxy resin having a repeat number n of 0 as a raw material, the modified epoxy resin of the present invention does not contain a secondary hydroxyl group, and the dielectric properties and moisture resistance can be further improved. On the other hand, for example, when finely adjusting the adhesion to metals, 2 By using the epoxy resin of the present invention, it is possible to intentionally allow a suitable amount of secondary hydroxyl groups to be present in the modified epoxy resin of the present invention, as long as this does not significantly affect other physical properties such as moisture resistance.

[0039] In the reaction between a bifunctional epoxy resin represented by general formula (4) and diphenyl carbonate represented by formula (5), one molecule of diphenyl carbonate reacts with two epoxy groups (one epoxy resin molecule) of the bifunctional epoxy resin, resulting in linear polycondensation. Therefore, while the amounts of raw materials used need to be adjusted appropriately depending on the epoxy equivalent of the desired modified epoxy resin, it is desirable to use 0.8 to 1.2 moles of diphenyl carbonate represented by formula (5) per mole of bifunctional epoxy resin represented by formula (4), i.e., a bifunctional epoxy resin / diphenyl carbonate (molar ratio) in the range of 0.8 to 1.2. More preferably, the amount of diphenyl carbonate is 1.0 to 1.1 moles, and the bifunctional epoxy resin / diphenyl carbonate (molar ratio) is 0.90 to 1.0. It is also possible to replace a portion of the compound represented by general formula (5) with the above-mentioned bifunctional phenolic compound. As described above, by deliberately allowing an appropriate amount of secondary hydroxyl groups to be present in the modified epoxy resin of the present invention, it is possible to finely adjust the solvent solubility, dielectric properties, moisture resistance, adhesiveness, etc.

[0040] In the production method, it is preferable to use a catalyst, and the catalyst is preferably a compound having catalytic activity such that the diphenyl carbonate of formula (5) preferentially reacts with the epoxy group rather than the secondary hydroxyl group of the epoxy resin. Basic compounds are preferred, such as tertiary amines, cyclic amines, imidazole compounds, organic phosphorus compounds, and quaternary ammonium salts. These catalysts may be used alone or in combination of two or more.

[0041] The amount of catalyst used is usually 0.001 to 1 mass% of the reaction solids, but when these compounds are used as catalysts, the catalyst remains as residue in the resulting modified epoxy resin, which may deteriorate the insulating properties of the printed wiring board or shorten the pot life of the composition, so the content of catalyst-derived nitrogen in the modified epoxy resin is preferably 0.5 mass% or less, more preferably 0.3 mass% or less. Also, the content of catalyst-derived phosphorus in the modified epoxy resin is preferably 0.5 mass% or less, more preferably 0.3 mass% or less.

[0042] In the production 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 of the solvent include aromatic solvents, ketone solvents, amide solvents, glycol ether solvents, and ester solvents. These solvents may be used alone or in combination of two or more.

[0043] In the production method, the solids concentration during the reaction is preferably 35 to 100% by mass, more preferably 50 to 90% by mass, and even more preferably 70 to 90% by mass. If a highly viscous product is produced during the reaction, the reaction can be continued by adding additional solvent. After the reaction is complete, the solvent can be removed or further added as necessary.

[0044] The reaction temperature is set within a range that does not decompose the catalyst used. If the reaction temperature is too high, the catalyst may decompose, halting the reaction or degrading the resulting modified epoxy resin. If the reaction temperature is too low, the reaction may not proceed sufficiently to achieve the desired molecular weight. 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 typically 1 to 12 hours, preferably 3 to 10 hours. When using a low-boiling solvent such as acetone or methyl ethyl ketone, the reaction temperature can be maintained by conducting the reaction under high pressure using an autoclave. If the heat of reaction needs to be removed, this is usually achieved by evaporating, condensing, and refluxing the solvent using the heat of reaction, indirect cooling, or a combination of these.

[0045] The epoxy resin composition of the present invention is a resin composition containing at least the modified epoxy resin of the present invention and a curing agent. Furthermore, the epoxy resin composition of the present invention can be appropriately blended with other epoxy resins described below, as well as various additives such as inorganic fillers, coupling agents, and antioxidants, as needed. The epoxy resin composition of the present invention gives a cured product that fully satisfies the various physical properties required for various applications.

[0046] In the present invention, a curing agent refers to a substance that contributes to a crosslinking reaction with an epoxy resin. In the present invention, even substances that are usually called curing accelerators are considered to be curing agents as long as they contribute to the crosslinking reaction of an epoxy resin.

[0047] The content of the curing agent in the resin composition of the present invention is preferably 0.1 to 150 parts by mass, more preferably 2 to 130 parts by mass, per 100 parts by mass of the epoxy resin (or all epoxy resins including other epoxy resins if other epoxy resins are contained). Note that this refers to the amount of nonvolatile content (solid content) in the resin composition.

[0048] When the resin composition of the present invention contains other epoxy resins, the modified epoxy resin of the present invention preferably accounts for 1 to 99 mass % of the total epoxy resins, more preferably 50 mass % or more, and even more preferably 80 mass % or more. In the present invention, the term "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 liquids. Furthermore, the term "resin component" refers to the total of the modified epoxy resin of the present invention and other epoxy resins.

[0049] The curing agent used in the resin composition of the present invention is not particularly limited, and any curing agent generally known as an epoxy resin curing agent can be used. From the viewpoint of improving heat resistance, preferred curing agents include phenolic resins, amide compounds, imidazole compounds, and active ester curing agents. These curing agents may be used alone or in combination of two or more.

[0050] Examples of other curing agents include acrylic ester resins, melamine resins, urea resins, cationic polymerization agents, amine compounds, acid anhydrides, tertiary amines, organic phosphines, phosphonium salts, tetraphenylboron salts, organic acid dihydrazides, boron halide amine complexes, polymercaptan curing agents, isocyanate compounds, polyisocyanate compounds, blocked isocyanate compounds, carbodiimide compounds, etc. These other curing agents may be used alone, or two or more may be mixed in any combination and ratio.

[0051] The resin composition of the present invention may contain other epoxy resins in addition to the modified epoxy resin of the present invention. The use of other epoxy resins can compensate for insufficient physical properties or improve various physical properties. The epoxy resin preferably has two or more epoxy groups in the molecule, and more preferably has three or more epoxy groups. Examples include polyglycidyl ether compounds, polyglycidyl amine compounds, polyglycidyl ester compounds, alicyclic epoxy compounds, and other modified epoxy resins. These epoxy resins may be used alone, or two or more types of epoxy resins of the same type may be used in combination, or different types of epoxy resins may be used in combination.

[0052] The resin composition of the present invention may contain a solvent or a reactive diluent to adjust the viscosity of the resin composition appropriately when handling the composition to form a coating film. In the resin composition of the present invention, the solvent or reactive diluent is used to ensure the ease of handling and workability when molding the resin composition, and there is no particular limit to the amount used. In the present invention, the term "solvent" and the aforementioned term "solvent" are used to distinguish between them depending on the form of use, but the same or different substances may be used independently.

[0053] Examples of solvents that may be contained in the resin composition of the present invention include ketones such as acetone, methyl ethyl ketone (MEK), methyl isobutyl ketone, cyclohexanone, etc., esters such as ethyl acetate, ethers such as ethylene glycol monomethyl ether, amides such as N,N-dimethylformamide, N,N-dimethylacetamide, etc., alcohols such as methanol, ethanol, etc., alkanes such as hexane, cyclohexane, etc., aromatics such as toluene, xylene, etc. The above-mentioned solvents may be used alone, or two or more may be mixed in any combination and ratio.

[0054] 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 glycidyl amines.

[0055] These solvents or reactive diluents are preferably used in an amount of 90% by mass or less, particularly 20 to 80% by mass, based on nonvolatile content, with the appropriate type and amount being selected appropriately depending on the application. For example, for printed wiring 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, with the amount used being 40 to 80% by mass based on nonvolatile content. For adhesive film applications, for example, ketones, acetate esters, carbitols, aromatic hydrocarbons, dimethylformamide, dimethylacetamide, and N-methylpyrrolidone are preferred, with the amount used being 30 to 60% by mass based on nonvolatile content.

[0056] If necessary, a curing accelerator or catalyst can be used in the resin composition of the present invention. Examples of the curing accelerator or catalyst include imidazole compounds, tertiary amines, phosphorus compounds such as phosphines, metal compounds, Lewis acids, and amine complex salts. These may be used alone or in combination of two or more.

[0057] The amount of curing accelerator or catalyst may be appropriately selected depending on the intended use, but 0.01 to 15 parts by mass is used as needed per 100 parts by mass of the epoxy resin components in the resin composition (all epoxy resins including the modified epoxy resin of the present invention). It is preferably 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. The use of a curing accelerator or catalyst can lower the curing temperature and shorten the curing time.

[0058] In order to improve the flame retardancy of the resulting cured product, various known flame retardants can be used in the resin composition of the present invention, as long as the reliability is not reduced. Usable flame retardants include, for example, halogen-based flame retardants, phosphorus-based flame retardants, nitrogen-based flame retardants, silicone-based flame retardants, inorganic flame retardants, and organic metal salt-based flame retardants. From an environmental perspective, halogen-free flame retardants are preferred, and phosphorus-based flame retardants are particularly preferred. These flame retardants may be used alone, or two or more of the same type of flame retardants may be used in combination, or different types of flame retardants may be used in combination.

[0059] The resin composition of the present invention may contain components other than those described above in order to further improve its functionality, such as fillers, thermoplastic resins, thermosetting resins, photocurable resins, ultraviolet inhibitors, antioxidants, coupling agents, plasticizers, fluxes, thixotropic agents, smoothing agents, colorants, pigments, dispersants, emulsifiers, elasticity reducing agents, release agents, antifoaming agents, and ion trapping agents.

[0060] The resin composition of the present invention can be obtained by uniformly mixing the above-mentioned components. Resin compositions containing a modified epoxy resin, a curing agent, and, if necessary, various other components can be easily cured using methods similar to those known in the art. This cured product exhibits low moisture absorption, excellent dielectric properties, and good cured physical properties. "Curing" here refers to intentionally curing the resin composition using heat and / or light, etc., and the degree of curing can be controlled depending on the desired physical properties and application. The degree of progress may be fully cured or semi-cured, and is not particularly limited, but the reaction rate of the curing reaction between the epoxy groups and the curing agent is usually 5 to 95%.

[0061] The resin composition of the present invention can be cured to obtain a cured product by the same method as for known epoxy resin compositions. Methods for obtaining a cured product include those similar to those for known epoxy resin compositions, such as casting, injection, potting, dipping, drip coating, transfer molding, and compression molding, as well as laminating the resin in the form of a resin sheet, resin-coated copper foil, or prepreg, followed by heating and pressure curing to obtain a laminate. The curing temperature is typically in the range of 80 to 300°C, and the curing time is typically about 10 to 360 minutes. This heating is preferably carried out in two stages: a primary heating step at 80 to 180°C for 10 to 90 minutes, followed by a secondary heating step at 120 to 200°C for 60 to 150 minutes. Furthermore, for formulations whose glass transition temperature (Tg) exceeds the secondary heating temperature, a tertiary heating step at 150 to 280°C for 60 to 120 minutes is preferably carried out. Such secondary and tertiary heating steps can reduce poor curing. When producing a semi-cured resin product such as a resin sheet, a resin-coated copper foil, or a prepreg, the curing reaction of the resin composition is usually allowed to proceed to an extent that the shape can be maintained by heating, etc. When the resin composition contains a solvent, most of the solvent is usually removed by techniques such as heating, decompression, or air drying, but 5% by mass or less of the solvent may remain in the semi-cured resin product.

[0062] The prepreg obtained using the resin composition of the present invention will now be described. The prepreg of the present invention comprises the resin composition or a semi-cured product thereof and a fibrous substrate. The fibrous substrate can be, but is not limited to, woven or nonwoven fabrics made of inorganic fibers such as glass or organic fibers such as polyester, polyamine, polyacrylic, polyimide, Kevlar, or cellulose. The method for producing a prepreg from the resin composition of the present invention and the fibrous substrate is not particularly limited. For example, the substrate can be immersed 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, the prepreg can be obtained by heating and drying at 100 to 200°C for 1 to 40 minutes. The resin content in the prepreg is preferably 30 to 80% by mass.

[0063] A resin sheet obtained using the resin composition of the present invention will be described. The resin sheet of the present invention comprises the resin composition or a semi-cured product thereof and a support film. Examples of the support film include, but are not limited to, polyolefins such as polyethylene, polypropylene, and polyvinyl chloride; polyesters such as polyethylene terephthalate (PET) and polyethylene naphthalate; polycarbonate; polyimide; and even release paper and metal foils such as copper foil and aluminum foil. The thickness of the support film is not particularly limited, but is typically 10 to 150 μm, preferably 25 to 50 μm. The method for producing a resin sheet from the resin composition and support film of the present invention is not particularly limited, and examples include a method in which the resin composition is applied to the support film with a resin varnish whose viscosity has been adjusted with an aromatic or ketone solvent, followed by drying. The resin sheet is obtained by semi-curing (B-staging) the resin component by heating and drying, for example, at 100 to 200°C for 1 to 40 minutes. The resin content in the resin sheet is preferably 30 to 80% by mass. The thickness of the resin component is not particularly limited, but is preferably 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 case, it is also possible to repeat the coating using multiple solutions with different compositions and concentrations, and adjust the final resin composition and resin amount to the desired one.

[0064] A method for producing a laminate using the prepreg or resin sheet of the present invention will be described. When forming a laminate using prepreg, for example, one or more prepregs are laminated, and metal foil is placed on one or both sides to form a laminate, which is then heated and pressed to be integrated. The metal foil used here can be a single, alloy, or composite metal foil of copper, aluminum, brass, nickel, or the like. The conditions for heating and pressing the laminate can be appropriately adjusted to the conditions under which the resin composition hardens. If the 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 to 220°C and a pressure of 49 to 490 N / cm are used.2 (5-50kgf / cm 2 ) and the heating time can be set to 10 to 240 minutes. A resin sheet can also be used instead of the prepreg.

[0065] Furthermore, a multilayer board can be produced using the single-layer laminate obtained in this way as an inner layer material. In this case, a circuit is first formed on the laminate by an additive method, a subtractive method, or the like, and the surface of the formed circuit is blackened by treating it with an acid solution to obtain an inner layer material. An insulating layer is formed on one or both circuit-forming surfaces of this inner layer material using a prepreg or a resin sheet, and a conductor layer is formed on the surface of the insulating layer to form a multilayer board.

[0066] When forming an insulating layer using a resin sheet, a laminate is formed by placing a resin sheet on the circuit-forming surfaces of multiple inner layer materials. Alternatively, a resin sheet is placed between the circuit-forming surfaces of the inner layer materials and a metal foil to form a laminate. This laminate is then heated and pressurized to form an integral molding, thereby forming the cured resin sheet as an insulating layer and forming a multilayer inner layer material. Alternatively, the inner layer material and the metal foil as a conductor layer are combined to form the cured resin sheet as an insulating layer. Here, the metal foil can be the same as that used in the laminate used as the inner layer material. Furthermore, the hot and pressure molding can be carried out under the same conditions as those for molding the inner layer material. When forming an insulating layer by applying a resin composition to a laminate, the resin for forming the circuit on the outermost layer of the inner layer material is preferably applied to a thickness of 5 to 100 μm with the above-mentioned resin composition, 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 a casting method. The thickness after drying is preferably formed to 5 to 80 μm. A printed wiring board can be formed by further forming via holes and circuits on the surface of the multilayer laminate thus formed by an additive method or a subtractive method. Furthermore, by repeating the above process using this printed wiring board as an inner layer material, it is possible to form a multi-layer laminate.

[0067] When forming an insulating layer using prepreg, one or more prepreg sheets are placed on the circuit-forming surface of the inner layer material, and a metal foil is placed on the outside of the prepreg to form a laminate. This laminate is then heated and pressurized to form an integral molding, whereby the cured prepreg is formed as an insulating layer and the outer metal foil is formed as a conductor layer. Here, the metal foil may be the same as that used in the laminate used as the inner layer material. The hot-press molding can be carried out under the same conditions as those for molding the inner layer material. The surface of the multilayer laminate thus molded can be further subjected to via hole formation and circuit formation by an additive method or a subtractive method to mold a printed wiring board. Furthermore, by repeating the above process using this printed wiring board as an inner layer material, it is possible to form a multi-layer board with even more layers.

[0068] 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 wiring board. Specifically, for example, a resin sheet is produced by forming an epoxy resin composition into a sheet on a support film by a coating method or the like, and then heating it to dry or semi-cure it. This resin sheet is then placed on a substrate (first substrate), the support film is peeled off from the resin sheet, and another substrate (second substrate) is placed on top of it. That is, the first substrate, the resin sheet (epoxy resin composition), and the second substrate are laminated in this order. Subsequently, the first substrate and the second substrate are bonded together via the cured product of the epoxy resin composition by heating and curing.

[0069] The cured product and laminate for electric / electronic circuits obtained from the resin composition of the present invention have excellent low dielectric properties. [Example]

[0070] The present invention will be explained in more detail below with reference to examples and comparative examples, but is not limited to these. Unless otherwise specified, "parts" means parts by mass, and "%" means % by mass. Analytical and measurement methods are also shown below. The unit of equivalent weight is "g / eq."

[0071] (1) Weight average molecular weight (Mw): The chromatographic index was determined by GPC measurement. Specifically, a Tosoh HLC8320 GPC main unit equipped with columns (TSKgel SuperH-H, SuperH2000, SuperHM-H, and SuperHM-H, all manufactured by Tosoh) was used. The column temperature was 40°C. Tetrahydrofuran (THF) was used as the eluent at a flow rate of 1.0 mL / min, and a refractive index detector was used. 0.1 g of solids was dissolved in 10 mL of THF and filtered through a 0.45 μm microfilter. 50 μL of the sample was used. A calibration curve was prepared using standard polystyrenes (Tosoh PStQuick A, PStQuick B, and PStQuick C). Data processing was performed using a Tosoh GPC8020 Model II version 6.00. (2) IR (infrared absorption spectrum): A Fourier transform infrared spectrophotometer (Spectrum One FT-IR Spectrometer 1760X, manufactured by Perkin Elmer Precisely) was used, and sodium chloride was used as the cell. A sample dissolved in chloroform was applied to the cell, dried, and then the transmittance at wavenumbers of 500 to 4000 cm-1 was measured. (3) Nonvolatile content: Measured in accordance with JIS K7235. The drying temperature was 200°C and the drying time was 60 minutes. (4) Dielectric constant and dielectric loss tangent: The measurement equipment used was a Keysight Technologies network analyzer (E8363C) as the network analyzer and split post dielectric resonators (SPDR) as the resonators, and measurements were carried out in an environment of 23°C and 50% humidity. (5) Water absorption: Compliant with JIS K7209. The test specimens were the same as those used to measure the dielectric constant and dielectric loss tangent, and were immersed in water at 23°C for 24 hours.

[0072] The materials used in the examples and comparative examples are as follows. [Bifunctional epoxy resin] A1: 2,5-di-tert-butylhydroquinone diglycidyl ether (manufactured by Nippon Steel Chemical & Material Co., Ltd., YDC-1312, epoxy equivalent weight 177, n 2 ≒0.05) [ka] A2: 2-phenylhydroquinone diglycidyl ether (epoxy equivalent weight 149) [ka] A3: Bisphenol A liquid epoxy resin (manufactured by Nippon Steel Chemical & Material Co., Ltd., Y D-128, epoxy equivalent weight 186, n 2 ≒0.11) [ka] A4: Hydroquinone diglycidyl ether (epoxy equivalent weight 111) [ka] [Carbonate ester compounds] B1: Diphenyl carbonate (Tokyo Chemical Industry Co., Ltd., active equivalent weight 107) [ka] [catalyst] D1: 4-Dimethylaminopyridine (Fujifilm Wako Pure Chemical Industries, Ltd.) [ka] [Solvents] E1: Cyclohexanone E2: Methyl ethyl ketone (MEK)

[0073] Example 1 A four-necked glass separable flask equipped with a stirrer, thermometer, condenser, and nitrogen gas inlet was charged with 100 parts of 2,5-di-tert-butylhydroquinone diglycidyl ether (A1) as an epoxy resin, 63 parts of diphenyl carbonate (B1) as a carbonate ester compound, and 54 parts of reaction solvent E1 at room temperature. The mixture was heated to 125°C while stirring under a nitrogen gas stream. After adding 0.2 parts of catalyst (D1), the mixture was heated to 145°C and reacted at the same temperature for 7 hours. The mixture was diluted and mixed with 27 parts of dilution solvent E1 and 163 parts of dilution solvent E2 to obtain a modified epoxy resin varnish (R1) with a nonvolatile content of 40%. Figure 1 shows the GPC chart and Figure 2 shows the IR chart of the resulting modified epoxy resin (R1). The resulting modified epoxy resin (R1) is a compound represented by the general formula (1), with a repeating number n 1 is 17, R1 of Y is a tert-butyl group, m is 2, and it accounts for 100 mol % of all Y. As for the terminal group X, the structure of formula (2-1) accounts for 48 mol %, and the structure of formula (2-2) accounts for 52 mol %.

[0074] Examples 2 to 6, Comparative Examples 1 and 2 The same operations as in Example 1 were carried out using the amounts (parts) of each raw material shown in Table 1 to obtain resin varnishes according to Examples 2 to 6 (R2 to R6) and resin varnishes according to Comparative Examples 1 and 2 (HR1, HR2). The results are shown in Table 1. The "molar ratio" in the table indicates the molar ratio of the difunctional epoxy resin to diphenyl carbonate (difunctional epoxy resin / diphenyl carbonate).

[0075] [Table 1]

[0076] Resin varnishes R1 to R6 and HR1 and HR2 obtained in Examples 1 to 6 and Comparative Examples 1 and 2 were applied to an iron plate so that the film thickness after drying would be 100 μm, and then dried in a dryer at 150°C for 1 hour to obtain a resin film. The Mw of the resin varnishes and the water absorption, dielectric constant, and dielectric loss tangent of the resin films were measured. The results are shown in Table 2.

[0077] [Table 2]

[0078] As can be seen from Table 2, the modified epoxy resins of the present invention shown in Examples 1 to 6 are excellent in dielectric properties and water absorbency.

Claims

1. A modified epoxy resin represented by the following general formula (1), characterized in that the weight average molecular weight determined by gel permeation chromatography is 500 to 100,000: 【Chemical Formula 1】 Here, X is a monovalent group represented by the above formula (2-1) or (2-2), and the above formula (2-1) and the above formula (2-2) may be mixed in one molecule. Y is a divalent group and has at least a divalent group represented by the above formula (3). R １ are independently selected from alkyl groups having 1 to 12 carbon atoms, alkoxy groups having 1 to 12 carbon atoms, aryl groups having 6 to 12 carbon atoms, alkenyl groups having 2 to 12 carbon atoms, and alkynyl groups having 2 to 12 carbon atoms. m is 1 or more and 4 or less. n １ is the average number of repetitions, and is 0 to 500. １ When n is 0, X has at least a group represented by formula (2-2). ２ is the average number of repetitions, and is 0 to 6.

2. 2. The modified epoxy resin according to claim 1, wherein Y is a divalent group and the divalent group represented by the formula (3) accounts for at least 5% by mass.

3. R １ 2. The modified epoxy resin according to claim 1, wherein each of the groups is independently selected from an alkyl group having 4 or more carbon atoms and an aryl group having 6 to 12 carbon atoms, and m is 1 or more and 2 or less.

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

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

8. A laminate formed by laminating the prepreg according to claim 6 and / or the resin sheet according to claim 7.

9. 2. The method for producing a modified epoxy resin according to claim 1, comprising reacting a bifunctional epoxy resin represented by the following general formula (4) with diphenyl carbonate represented by the following formula (5): 【Chemistry 2】 Here, Y, n ２ has the same meaning as in formula (1). G is a monovalent group represented by formula (2-1) above.

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