JP2020045421A - Epoxy resin composition and cured product thereof - Google Patents

Abstract

To provide an epoxy resin composition for a printed wiring board having a low phosphorus content and having excellent heat resistance and flame retardancy.SOLUTION: A composition contains a biphenyl aralkyl epoxy resin represented by formula (1), a curing agent, and a phosphorus-containing epoxy resin.SELECTED DRAWING: None

Description

  The present invention relates to an epoxy resin composition used for producing a printed wiring board or a multilayer printed wiring board having high heat resistance and excellent flame retardancy, and a prepreg, a laminate, or a printed wiring board obtained from the epoxy resin composition. .

  Epoxy resin compositions have excellent adhesiveness, flexibility, heat resistance, chemical resistance, insulation, and curing reactivity, and are used in a wide variety of applications such as paint, civil engineering, casting, electrical and electronic materials, and film materials. I have. In particular, in the use of printed wiring boards as one of electric and electronic materials, it is widely used to impart flame retardancy to epoxy resin compositions.

  2. Description of the Related Art In recent years, in order to make electronic devices flame-retardant, measures have been taken to reduce toxic gas generated during combustion in consideration of the influence on the environment. From the flame retardation by a halogen-containing compound typified by a conventional brominated epoxy resin, the flame retardation is achieved by an organic phosphorus compound, that is, halogen-free flame retardation. These measures are widely used and recognized not only for electronic circuit boards but also as phosphorus flame retardants, and the same applies to the field of epoxy resins related to circuit boards.

  As specific representative examples of such an epoxy resin having flame retardancy, proposals have been made to apply an organic phosphorus compound as disclosed in Patent Documents 1 to 4. Patent Document 1 discloses a thermosetting resin obtained by reacting 9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide with epoxy resins at a predetermined molar ratio.

  In Patent Documents 1 and 2, since a phosphorus compound exhibiting flame retardancy is reacted with a polyfunctional epoxy resin, the heat resistance after curing using a curing agent has a glass transition temperature (Tg) equivalent to that of an FR-4 substrate. However, in recent years, as high-density mounting of boards and mounting from a car cabin to the vicinity of a bonnet drive part are progressing, Tg having heat resistance equivalent to FR-5 is required as a higher temperature correspondence. That is the reality.

  Patent Document 3 describes a specific example in which a phosphorus-containing epoxy resin is used in combination with a trifunctional epoxy resin capable of obtaining a higher Tg than a conventional novolak epoxy resin, and the cured product has a Tg of about 180 ° C. ing. Patent Document 4 discloses a highly heat-resistant phosphorus-containing epoxy resin obtained by reacting a phosphorus-containing oligomer obtained by reacting a phosphorus compound with hydroxybenzaldehyde with a polyfunctional epoxy resin, and having a cured product having a Tg of 185 ° C. Some specific examples are disclosed. Numerous technologies have been disclosed as substrates having a heat resistance standard equivalent to FR-5, and are being widely used.

  In any of these documents, a high phosphorus content is required in order to ensure flame retardancy, and establishment of a technique for expressing high flame retardancy even with a low phosphorus content has been demanded.

JP-A-11-166035 JP-A-11-279258 JP-A-2002-206019 JP 2013-35921 A

  The problem to be solved by the present invention is to provide an epoxy resin composition that exhibits excellent heat resistance and flame retardancy in a cured product even at a low phosphorus content, and provides excellent cured product properties particularly for printed wiring board applications. To provide things.

  In order to solve the above-described problems, the present inventors have conducted intensive studies on epoxy resins, and as a result, obtained when an epoxy resin having a structure obtained from a biphenol compound and a biphenyl-based condensing agent was added to a phosphorus-containing epoxy resin. The inventors have found that the heat resistance and flame retardancy of the cured product are excellent even when the phosphorus content is low, and completed the present invention.

ここで、ｎは繰り返し数であって０以上の数を示し、その平均値は１．３〜２０の数であり、Ｒ^１、Ｒ^２およびＲ^３はそれぞれ独立に水素原子または炭素数１〜８の炭化水素基を表す。 That is, the present invention is an epoxy resin composition comprising an epoxy resin and a curing agent as essential components, wherein the epoxy resin comprises a biphenylaralkyl-type epoxy resin represented by the following general formula (1) and a phosphorus-containing epoxy resin. It is an epoxy resin composition characterized by the above-mentioned.

Here, n is the number of repetitions and indicates a number of 0 or more, and the average value is a number of 1.3 to 20, and R ¹ , R ² and R ³ are each independently a hydrogen atom or a carbon number of 1 to 1. 8 represents a hydrocarbon group.

  The phosphorus-containing epoxy resin has an epoxy equivalent of 200 to 1000 g / eq. Is preferable, and the phosphorus content is preferably 1.0 to 6.0% by mass.

  Further, the present invention is a prepreg, a laminated board, or a printed wiring board using the epoxy resin composition.

  The epoxy resin composition of the present invention exhibits excellent heat resistance and flame retardancy even at a low phosphorus content in the cured product thereof, so that it is useful for printed wiring board applications, particularly for automotive applications where high reliability is required. Useful for substrates.

Hereinafter, embodiments of the present invention will be described in detail.
The epoxy resin composition of the present invention comprises an epoxy resin (A) and a curing agent (B) as essential components, wherein the epoxy resin (A) is a biphenylaralkyl-type epoxy resin (a1) represented by the general formula (1); An epoxy resin composition comprising a phosphorus-containing epoxy resin (a2) as an essential component.

  The epoxy resin (A) contains a biphenyl aralkyl type epoxy resin (a1) and a phosphorus-containing epoxy resin (a2) as essential components, and may contain various other epoxy resins (a3). In order to exhibit heat resistance and flame retardancy at a low phosphorus content, the biphenyl aralkyl type epoxy resin (a1) is preferably 5% by mass or more and 30% by mass or less, and more preferably 7% by mass or less in the total epoxy resin (A). It is more preferably at most 25% by mass.

In the general formula (1), R ¹ , R ² and R ³ each independently represent a hydrogen atom or a hydrocarbon group having 1 to 8 carbon atoms. Examples of the hydrocarbon group having 1 to 8 carbon atoms include an alkyl group having 1 to 8 carbon atoms such as a methyl group, an ethyl group, a propyl group, an isopropyl group, an n-butyl group, a t-butyl group, and a hexyl group. C5-C8 cycloalkyl group such as cyclohexyl group, C6-C8 aryl group such as phenyl group, tolyl group, xylyl group, and carbon number such as benzyl group, phenethyl group and 1-phenylethyl group 7 to 8 aralkyl groups, but are not limited thereto, and may be the same or different. Preferred R ¹ , R ² , and R ³ are a hydrogen atom, a 1-phenylethyl group, or a methyl group from the viewpoints of easy availability and physical properties such as heat resistance when a cured product is obtained.

  n is the number of repetitions and indicates a number of 0 or more, and the average value (number average) is 1.3 to 20, preferably 1.5 to 15, more preferably 1.7 to 10, and 2 to 6 Is more preferred.

  The weight average molecular weight (Mw) of the biphenyl aralkyl type epoxy resin (a1) measured by gel permeation chromatography (GPC) is preferably from 1,000 to 8,000, more preferably from 2,000 to 7000, still more preferably from 3,000 to 6,000.

  The content of the n = 0 component in which n is 0 is preferably less than 15%, more preferably 10% or less, and still more preferably 6% or less, in terms of area% by GPC measurement from the viewpoint of solvent solubility. In particular, in the case of being used by dissolving in an organic solvent for laminated board use, the content is preferably 2 to 5%. The content of n = 5 or more components is preferably 20% or more, more preferably 25% or more, and even more preferably 27% or more from the viewpoint of improving heat resistance. The GPC measurement conditions are based on the method described in the examples.

  The epoxy equivalent (g / eq.) Of the biphenyl aralkyl type epoxy resin (a1) is preferably 200 to 240, more preferably 205 to 235, and still more preferably 210 to 230. Further, the softening point is preferably from 70 to 130C, more preferably from 80 to 120C, even more preferably from 90 to 110C.

  The biphenyl aralkyl type epoxy resin (a1) can be produced by a method disclosed in WO2011 / 074517 or the like. Specifically, this is a method of reacting the biphenol compound and the biphenyl-based condensing agent in less than 1 mol of the biphenyl-based condensing agent per 1 mol of the biphenol compound to epoxidize the obtained biphenylaralkyl-type phenol resin.

  Examples of the biphenol compound include 4,4'-biphenol, 2,4'-biphenol, and 2,2'-biphenol, and from the viewpoint of reactivity, 4,4'-biphenol is preferable. Further, these biphenol compounds may have one hydrocarbon group having 1 to 8 carbon atoms as a substituent on each aromatic ring.

  Examples of the biphenyl-based condensing agent include biphenyl-4,4'-dimethanol, 4,4'-bis (chloromethyl) biphenyl, 4,4'-bis (bromomethyl) biphenyl, and 4,4'-bis (methoxymethyl). ) Biphenyl, 4,4'-bis (ethoxymethyl) biphenyl, biphenyl-2,4'-dimethanol, 2,4'-bis (chloromethyl) biphenyl, 2,4'-bis (bromomethyl) biphenyl, 2, 4'-bis (methoxymethyl) biphenyl, 2,4'-bis (ethoxymethyl) biphenyl, biphenyl-2,2'-dimethanol, 2,2'-bis (chloromethyl) biphenyl, 2,2'-bis (Bromomethyl) biphenyl, 2,2′-bis (methoxymethyl) biphenyl, 2,2′-bis (ethoxymethyl) biphenyl and the like. . From the viewpoint of reactivity, biphenyl-4,4'-dimethanol and 4,4'-bis (chloromethyl) biphenyl are preferred. From the viewpoint of reducing ionic impurities, biphenyl-4,4'-dimethanol is preferred. And 4,4′-bis (methoxymethyl) biphenyl are preferred. Further, these biphenyl-based condensing agents may have one or two hydrocarbon groups having 1 to 8 carbon atoms as substituents on each aromatic ring.

  For the reaction between the biphenol compound and the biphenyl-based condensing agent, an excess amount of the biphenol compound is used relative to the biphenyl-based condensing agent. The amount of the biphenyl-based condensing agent to be used is preferably 0.1 to 0.55 mol, more preferably 0.3 to 0.5 mol, per 1 mol of the biphenol compound. If the amount of the biphenyl-based condensing agent is too large, the amount of the unreacted raw material biphenol compound decreases, but the molecular weight itself increases, the softening point and melt viscosity of the resin increase, and there is a possibility that the moldability and workability may be affected. . On the other hand, if the amount is too small, the amount of the unreacted raw material biphenol compound after the completion of the reaction increases, which is not industrially preferable.

  Usually, this reaction is carried out in the presence of a known acid catalyst such as an inorganic acid and an organic acid. Examples of such an acid catalyst include mineral acids such as hydrochloric acid, sulfuric acid, and phosphoric acid, organic acids such as formic acid, oxalic acid, trifluoroacetic acid, and p-toluenesulfonic acid, zinc chloride, aluminum chloride, and iron chloride. Examples include Lewis acids such as boron trifluoride, and solid acids such as activated clay, silica-alumina, and zeolite.

  Usually, this reaction is carried out at 10 to 250 ° C. for 1 to 20 hours. Further, as a solvent during the reaction, for example, alcohols such as methanol, ethanol, propanol, butanol, ethylene glycol, methyl cellosolve, ethyl cellosolve, ethers such as diethylene glycol dimethyl ether, triglyme, and halogens such as chlorobenzene, dichlorobenzene It is preferable to use a hydrogenated aromatic compound or the like, and among them, ethyl cellosolve, diethylene glycol dimethyl ether, triglyme and the like are particularly preferable.

  Since the biphenylaralkyl-type phenol resin obtained by the above method may contain a large amount of unreacted raw material biphenol compound, it is preferable to add a step of removing the unreacted raw material biphenol compound after the reaction, if necessary. From the viewpoint of solvent solubility, the content of the unreacted raw material biphenol compound is preferably less than 15% (area% by GPC measurement), more preferably 10% or less, still more preferably 6% or less, and particularly preferably 3 to 5%. preferable.

  In the step of removing the unreacted raw material biphenol compound of the biphenyl aralkyl type phenol resin, for example, a solvent obtained by mixing a poor solvent and a good solvent is used to dissolve the generated high molecular weight component without dissolving the raw material biphenol compound. Then, it is preferable to remove the unreacted starting biphenol compound by a method such as filtration. The poor solvent is not particularly limited as long as it hardly dissolves the raw material biphenol compound, and examples thereof include aromatic solvents such as benzene, toluene, and xylene. Examples of the good solvent include the above-mentioned alcohols, ethers, halogenated aromatic compounds, and ketones such as acetone, methyl ethyl ketone, methyl isobutyl ketone, and cyclohexanone.

  The softening point of the biphenyl aralkyl type phenolic resin can be easily adjusted by changing the molar ratio of the biphenol compound and the biphenyl-based condensing agent, but the molar ratio of the biphenol compound and the biphenyl-based condensing agent is reduced so as to reduce the high molecular weight component. When the ratio is changed, the content of the unreacted raw material biphenol compound that needs to be removed increases, so that the workability deteriorates and the yield greatly decreases, so that there is a limit.

  The biphenyl aralkyl type epoxy resin (a1) used in the present invention can be produced by reacting the above biphenyl aralkyl type phenol resin with epichlorohydrin. This reaction can be performed in the same manner as a usual epoxidation reaction. For example, after dissolving a biphenylaralkyl-type phenol resin in excess epichlorohydrin, 50 to 150 ° C. in the presence of an alkali metal hydroxide such as sodium hydroxide or potassium hydroxide, preferably 1 to 10 hours at 60 to 120 ° C. A method for causing the reaction is mentioned. At this time, the amount of the alkali metal hydroxide to be used is 0.8 to 1.2 mol, preferably 0.9 to 1.0 mol, per 1 mol of the hydroxyl group in the biphenylaralkyl-type phenol resin. Further, epichlorohydrin is used in excess with respect to the hydroxyl group in the biphenylaralkyl-type phenol resin, but is usually 1.5 to 15 mol, preferably 2 to 8 mol, per 1 mol of the hydroxyl group in the biphenylaralkyl-type phenol resin. . After completion of the reaction, excess epichlorohydrin is distilled off, and the residue is dissolved in a solvent such as toluene, methyl isobutyl ketone, filtered, washed with water to remove inorganic salts, and then the solvent is distilled off to obtain a biphenylaralkyl. Mold epoxy resin can be obtained. In the epoxidation, the epoxy group of the produced epoxy compound may be ring-opened and condensed to form a small amount of an oligomerized epoxy compound as a by-product. However, such an epoxy compound may be present.

  The phosphorus-containing epoxy resin (a2) used in the present invention is preferably used alone or in combination of two or more. Further, a phosphorus-free epoxy resin (a3) may be used in combination. Examples of the phosphorus-containing epoxy resin (a2) include those disclosed in JP-A-04-11662, JP-A-05-214070, JP-A-2000-309624, and JP-A-2002-265562. , 9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide and a reactive phosphorus compound such as diphenylphosphine oxide and, if necessary, 1,4-benzoquinone and 1,4-naphthoquinone. Those obtained by reacting with a quinone compound and then reacting with an epoxy resin are particularly preferred.

  The epoxy equivalent (g / eq.) Of these phosphorus-containing epoxy resins (a2) is preferably from 200 to 1,000, more preferably from 250 to 800, even more preferably from 270 to 700. The phosphorus content is preferably from 1.0 to 6.0% by mass, more preferably from 1.5 to 5.5% by mass, and still more preferably from 1.7 to 5.0% by mass.

  When the phosphorus-free epoxy resin (a3) is used in combination, the phosphorus content of the phosphorus-containing epoxy resin (a23) in which the phosphorus-containing epoxy resin (a2) and the phosphorus-free epoxy resin (a3) are mixed is such that the phosphorus-containing epoxy resin (a23) is used. The phosphorus content of the phosphorus-containing epoxy resin (a2) and the mixing amount of the phosphorus-containing epoxy resin (a2) and the phosphorus-free epoxy resin (a3) are adjusted so as to fall within the preferred range of the phosphorus content of the resin (a2). I do.

  The phosphorus content of the epoxy resin composition for achieving V-0 of the flame retardancy test UL-94 is preferably 1.0 to 5.0% by mass, more preferably 1.3 to 4.5% by mass. preferable. 1.5 to 2.3% by weight is particularly preferred. When the phosphorus content in the epoxy resin composition is low, the flame retardancy may be insufficient, and when the phosphorus content is high, the heat resistance and adhesion may be impaired.

  Specific examples of the phosphorus-containing epoxy resin (a2) include, for example, Epotote FX-305, Epotote FX-289B, Epotote FX-1225, YDFR-1320, and TX-1328 (all manufactured by Nippon Steel & Sumikin Chemical Co., Ltd.). However, the present invention is not limited to these.

  The phosphorus-free epoxy resin (a3) that can be used in combination is not particularly limited, and a normal epoxy resin having two or more epoxy groups in a molecule can be used, and a trifunctional or higher functional epoxy resin is preferable. For example, bisphenol A epoxy resin, bisphenol F epoxy resin, tetramethyl bisphenol F epoxy resin, hydroquinone epoxy resin, biphenyl epoxy resin, bisphenol fluorene epoxy resin, bisphenol S epoxy resin, bisthioether epoxy resin, Resorcinol type epoxy resin, biphenyl aralkyl type epoxy resin other than the structure represented by the above general formula (1), naphthalene diol type epoxy resin, phenol novolak type epoxy resin, aromatic modified phenol novolak type epoxy resin, cresol novolak type epoxy resin , Alkyl novolak epoxy resin, bisphenol novolak epoxy resin, naphthol novolak epoxy resin, β-naphthol aralkyl epoxy resin Xy resin, dinaphthol aralkyl epoxy resin, α-naphthol aralkyl epoxy resin, trisphenylmethane epoxy resin, alkylene glycol epoxy resin, aliphatic cyclic epoxy resin, diaminodiphenylmethanetetraglycidylamine, aminophenol epoxy resin, urethane Examples include a modified epoxy resin and an oxazolidone ring-containing epoxy resin, but are not limited thereto. From the viewpoint of availability, naphthalene diol type epoxy resin, phenol novolak type epoxy resin, aromatic modified phenol novolak type epoxy resin, cresol novolak type epoxy resin, α-naphthol aralkyl type epoxy resin, dicyclopentadiene type epoxy resin, oxazolidone Ring-containing epoxy resins are preferred.

  The curing agent (B) in the epoxy resin composition of the present invention is not particularly limited, and a conventionally known curing agent can be used. For example, those usually used such as a phenolic resin-based curing agent, an acid anhydride-based curing agent, an amine-based curing agent, and other curing agents may be mentioned, but these curing agents may be used alone. Two or more types may be used in combination.

  In the epoxy resin composition of the present invention, the amount of the curing agent (B) used is such that the active hydrogen groups of the curing agent (B) are at least 0.2 mol and 1 mol of the epoxy groups of the entire epoxy resin (A). 0.5 mol or less. When the amount of the active hydrogen group is less than 0.2 mol or more than 1.5 mol per 1 mol of the epoxy group, curing may be incomplete and good cured physical properties may not be obtained. A preferred range is from 0.3 mol to 1.5 mol, a more preferred range is from 0.5 mol to 1.5 mol, and a still more preferred range is from 0.8 mol to 1.2 mol. For example, when a phenolic resin-based curing agent or an amine-based curing agent is used, an active hydrogen group is blended in an approximately equimolar amount with respect to an epoxy group, and when an acid anhydride-based curing agent is used, 1 mol of an epoxy group is used. The acid anhydride group may be compounded in an amount of 0.5 to 1.2 mol, preferably 0.6 to 1.0 mol.

The active hydrogen group referred to in the present invention is a functional group having an active hydrogen reactive with an epoxy group (including a functional group having a latent active hydrogen that generates an active hydrogen by hydrolysis or the like, and a functional group having an equivalent curing action). ), And specific examples include an acid anhydride group, a carboxyl group, an amino group, and a phenolic hydroxyl group. With respect to active hydrogen groups, one mole of a carboxyl group or a phenolic hydroxyl group is calculated as one mole, and _two moles of an amino group (NH ₂ ) are calculated. When the active hydrogen group is not clear, the active hydrogen equivalent can be determined by measurement. For example, by reacting a monoepoxy resin such as phenylglycidyl ether having a known epoxy equivalent with a curing agent having an unknown active hydrogen equivalent, and measuring the amount of consumed monoepoxy resin, the active hydrogen equivalent of the used curing agent is measured. Can be requested.

  Specific examples of the phenolic resin-based curing agent include bisphenol A, bisphenol F, bisphenol C, bisphenol K, bisphenol Z, bisphenol S, tetramethylbisphenol A, tetramethylbisphenol F, tetramethylbisphenol S, and tetramethylbisphenol Z. , Dihydroxydiphenyl sulfide, bisphenols such as 4,4′-thiobis (3-methyl-6-t-butylphenol), the above-mentioned biphenol compounds, catechol, resorcin, methylresorcin, hydroquinone, monomethylhydroquinone, dimethylhydroquinone, trimethylhydroquinone Dihydroxybenzenes such as mono-t-butylhydroquinone, di-t-butylhydroquinone, dihydroxynaphthalene, dihydric Hydroxynaphthalenes such as xylmethylnaphthalene and trihydroxynaphthalene; phosphorus-containing phenol curing agents such as LC-950PM60 (manufactured by Shin-AT &C); and phenol novolak resins such as Shaunol BRG-555 (manufactured by Aika Kogyo). Novolak resin, aromatic modified phenol novolak resin, bisphenol A novolak resin such as DC-5 (manufactured by Nippon Steel & Sumikin Chemical Co., Ltd.), and trishydroxyphenylmethane type such as resin top TPM-100 (manufactured by Gunei Chemical Industry Co., Ltd.) Phenols such as novolak resin and naphthol novolak resin; condensates of naphthols and / or bisphenols with aldehydes; phenols such as SN-160, SN-395, and SN-485 (manufactured by Nippon Steel & Sumikin Chemical Co., Ltd.) Condensates of naphthols and / or bisphenols with xylylene glycol, condensates of phenols and / or naphthols with isopropenylacetophenone, reactants of phenols, naphthols and / or bisphenols with dicyclopentadiene And phenol compounds such as phenols, naphthols and / or condensates of bisphenols and biphenyl-based cross-linking agents. From the viewpoint of availability, phenol novolak resins, dicyclopentadiene type phenol resins, trishydroxyphenylmethane type novolak resins, aromatic modified phenol novolak resins, and the like are preferable.

  In the case of a novolak type phenol resin, phenols include phenol, cresol, xylenol, butyl phenol, amyl phenol, nonyl phenol, butyl methyl phenol, trimethyl phenol, phenyl phenol, etc., and naphthols include 1-naphthol, 2-naphthol Naphthol; and the above-mentioned biphenol compounds and bisphenols. Aldehydes include formaldehyde, acetaldehyde, propylaldehyde, butyraldehyde, valeraldehyde, caproaldehyde, benzaldehyde, chloraldehyde, bromaldehyde, glyoxal, malonaldehyde, succinaldehyde, glutaraldehyde, adipaldehyde, pimeraldehyde, sebacaldehyde , Acrolein, crotonaldehyde, salicylaldehyde, phthalaldehyde, hydroxybenzaldehyde and the like. Biphenyl-based crosslinking agents include bis (methylol) biphenyl, bis (methoxymethyl) biphenyl, bis (ethoxymethyl) biphenyl, bis (chloromethyl) biphenyl and the like.

  Specific examples of the acid anhydride-based curing agent include methyltetrahydrophthalic anhydride, hexahydrophthalic anhydride, pyromellitic anhydride, phthalic anhydride, trimellitic anhydride, methylnadic acid, and the like.

  Specific examples of the amine-based curing agent include diethylenetriamine, triethylenetetramine, metaxylenediamine, isophoronediamine, diaminodiphenylmethane, diaminodiphenylsulfone, diaminodiphenylether, benzyldimethylamine, 2,4,6-tris (dimethylaminomethyl ) Amine compounds such as polyamidoamine which is a condensate of acids such as phenol, dicyandiamide, dimer acid and polyamines.

  As other curing agents, specifically, phosphine compounds such as triphenylphosphine, phosphonium salts such as tetraphenylphosphonium bromide, 2-methylimidazole, 2-phenylimidazole, 2-ethyl-4-methylimidazole, 2-un Decyl imidazole, imidazoles such as 1-cyanoethyl-2-methylimidazole, imidazoles which are salts of imidazoles with trimellitic acid, isocyanuric acid or boric acid, quaternary ammonium salts such as trimethylammonium chloride, diazabicyclo compounds, Salts of diazabicyclo compounds with phenols and phenol novolak resins, complex compounds of boron trifluoride with amines and ether compounds, aromatic phosphonium salts, iodonium salts and the like can be mentioned.

  A curing accelerator can be used as needed in the epoxy resin composition. Examples of curing accelerators that can be used include imidazoles such as 2-methylimidazole, 2-ethylimidazole, 2-ethyl-4-methylimidazole, 2- (dimethylaminomethyl) phenol, 1,8-diaza-bicyclo (5 Tertiary amines such as (4,0,0) undecene-7; phosphines such as triphenylphosphine, tricyclohexylphosphine and triphenylphosphinetriphenylborane; and metal compounds such as tin octylate. The curing accelerator is used in an amount of 0.02 to 5 parts by mass, as needed, with respect to 100 parts by mass of the epoxy resin component in the epoxy resin composition of the present invention. By using a curing accelerator, the curing temperature can be lowered and the curing time can be shortened.

  In the epoxy resin composition, an organic solvent or a reactive diluent can be used for adjusting the viscosity.

  Examples of the organic solvent include amides such as N, N-dimethylformamide and N, N-dimethylacetamide, and ethers such as ethylene glycol monomethyl ether, dimethoxydiethylene glycol, ethylene glycol diethyl ether, diethylene glycol diethyl ether, and triethylene glycol dimethyl ether. And ketones such as acetone, methyl ethyl ketone, methyl isobutyl ketone and cyclohexanone, methanol, ethanol, 1-methoxy-2-propanol, 2-ethyl-1-hexanol, benzyl alcohol, ethylene glycol, propylene glycol and butyl diglycol , Alcohols such as pine oil, butyl acetate, methoxybutyl acetate, methyl cellosolve acetate, cellosolve acetate Acetates such as ethyl diglycol acetate, propylene glycol monomethyl ether acetate, carbitol acetate and benzyl alcohol acetate; benzoates such as methyl benzoate and ethyl benzoate; and cellosolves such as methyl cellosolve, cellosolve and butyl cellosolve And carbitols such as methyl carbitol, carbitol, and butyl carbitol; aromatic hydrocarbons such as benzene, toluene and xylene; dimethyl sulfoxide, acetonitrile, and N-methylpyrrolidone. It is not limited.

  Examples of the reactive diluent include monofunctional glycidyl ethers such as allyl glycidyl ether, butyl glycidyl ether, 2-ethylhexyl glycidyl ether, phenyl glycidyl ether, and tolyl glycidyl ether; resorcinol diglycidyl ether; neopentyl glycol diglycidyl ether. Glycidyl ethers such as 1,4-butanediol diglycidyl ether, 1,6-hexanediol diglycidyl ether, cyclohexane dimethanol diglycidyl ether, propylene glycol diglycidyl ether, glycerol polyglycidyl ether, and trimethylolpropane Polyglycidyl ether, trimethylolethane polyglycidyl ether, pentaerythritol polyglycidyl ether Polyfunctional glycidyl ethers or, or glycidyl esters such as neodecanoic acid glycidyl ester, phenyl diglycidyl amine, although glycidyl amines such as tolyl diglycidyl amines, but not limited thereto.

  These organic solvents or reactive diluents are preferably used alone or as a mixture of two or more kinds at a non-volatile content of 90% by mass or less, and the appropriate kind and amount used are appropriately selected depending on the application. For example, for use in printed wiring boards, polar solvents having a boiling point of 160 ° C. or lower, such as methyl ethyl ketone, acetone, and 1-methoxy-2-propanol, are preferably used, and the amount used is preferably 40 to 80% by mass in terms of nonvolatile components. Further, in the adhesive film application, for example, it is preferable to use ketones, acetates, carbitols, aromatic hydrocarbons, dimethylformamide, dimethylacetamide, N-methylpyrrolidone, etc. Is preferably 30 to 60% by mass.

  The epoxy resin composition may contain another thermosetting resin or a thermoplastic resin as long as the properties are not impaired. For example, phenolic resin, acrylic resin, petroleum resin, indene resin, coumarone indene resin, phenoxy resin, polyurethane resin, polyester resin, polyamide resin, polyimide resin, polyamideimide resin, polyetherimide resin, polyphenylene ether resin, modified polyphenylene ether Examples include, but are not limited to, resins, polyether sulfone resins, polysulfone resins, polyether ether ketone resins, polyphenylene sulfide resins, polyvinyl formal resins, and the like.

  Various known flame retardants can be used in combination with the epoxy resin composition for the purpose of improving the flame retardancy of the obtained cured product. Examples of the flame retardant that can be used in combination include a phosphorus-based flame retardant, a nitrogen-based flame retardant, a silicone-based flame retardant, and an inorganic flame retardant, and a phosphorus-based flame retardant is particularly preferable. These flame retardants may be used alone or in combination of two or more.

  As the phosphorus-based flame retardant, any of inorganic phosphorus-based compounds and organic phosphorus-based compounds can be used. Examples of the inorganic phosphorus-based compound include inorganic phosphorus-containing phosphorus compounds such as red phosphorus, monoammonium phosphate, diammonium phosphate, triammonium phosphate, ammonium phosphate and the like, and phosphate amides and the like. Can be Examples of the organic phosphorus compound include aliphatic phosphate esters, phosphate ester compounds, for example, condensed phosphate esters such as PX-200 (manufactured by Daihachi Chemical Industry Co., Ltd.), phosphonic acid compounds, phosphinic acid compounds, General-purpose organic phosphorus compounds such as phosphine oxide compounds such as PPQ (manufactured by Hokko Chemical Industry Co., Ltd.), phosphorane compounds, and organic nitrogen-containing phosphorus compounds such as phosphazene; metal salts of phosphinic acid; and 9,10-dihydro- 9-oxa-10-phosphaphenanthrene-10-oxide (DOPO), 10- (2,5-dihydroxyphenyl) -10H-9-oxa-10-phosphaphenanthrene-10-oxide, 10- (2 7-dihydrooxynaphthyl) -10H-9-oxa-10-phosphaphenanthrene-10-oxo And cyclic organic phosphorus compounds such as de, phosphorus-containing curing agent such as those of a derivative with a compound such as phenol resin.

  The blending amount of the flame retardant is appropriately selected depending on the type of the phosphorus-based flame retardant, the components of the epoxy resin composition, and the desired degree of flame retardancy. Even when a phosphorus-based flame retardant is blended, for example, the phosphorus content in the organic component (excluding the organic solvent) in the epoxy resin composition is the sum of all the phosphorus compounds (the phosphorus-containing epoxy resin and the phosphorus-based flame retardant). The amount is preferably from 0.2% by mass to 4% by mass, more preferably from 0.4% by mass to 3.5% by mass, still more preferably from 0.6% by mass to 3% by mass. is there. If the phosphorus content is low, it may be difficult to ensure flame retardancy. If the phosphorus content is too high, the heat resistance may be adversely affected, and the object of the present invention cannot be achieved. Further, a flame retardant aid such as magnesium hydroxide may be used in combination.

  A filler can be used in the epoxy resin composition as needed. Specifically, fused silica, crystalline silica, alumina, silicon nitride, aluminum hydroxide, boehmite, magnesium hydroxide, talc, mica, calcium carbonate, calcium silicate, calcium hydroxide, magnesium carbonate, barium carbonate, barium sulfate, Examples include boron nitride, carbon, carbon fiber, glass fiber, alumina fiber, silica-alumina fiber, silicon carbide fiber, polyester fiber, cellulose fiber, aramid fiber, ceramic fiber, fine particle rubber, thermoplastic elastomer, and pigment. Generally, the reason for using a filler is an effect of improving impact resistance. When a metal hydroxide such as aluminum hydroxide, boehmite, or magnesium hydroxide is used, it acts as a flame-retardant aid and has the effect of improving flame retardancy. The amount of these fillers is preferably from 1 to 150 parts by mass, more preferably from 10 to 70 parts by mass, per 100 parts by mass of the epoxy resin composition. If the amount is too large, the adhesiveness required for a laminated board may be reduced, and the cured product may be brittle, and sufficient mechanical properties may not be obtained. On the other hand, if the compounding amount is small, there is a possibility that the compounding effect of the filler such as an improvement in impact resistance of the cured product is not obtained.

  When the epoxy resin composition is used as a plate-like substrate or the like, a fibrous filler is preferred as a filler in terms of dimensional stability, bending strength and the like. More preferably, a glass fiber substrate in which glass fibers are woven in a mesh shape is used.

  The epoxy resin composition further incorporates nuclide additives such as a silane coupling agent, an antioxidant, a release agent, an antifoaming agent, an emulsifier, a thixotropic agent, a smoothing agent, a flame retardant, and a pigment, if necessary. be able to. These additives are preferably in the range of 0.01 to 20 parts by mass based on 100 parts by mass of the epoxy resin composition.

  By impregnating the fibrous base material with the epoxy resin composition, a prepreg used for a printed wiring board or the like can be prepared. As the fibrous base material, an inorganic fiber such as glass, a polyester resin or the like, a polyamine resin, a polyacrylic resin, a polyimide resin, an organic fiber such as an aromatic polyamide resin, or a woven or nonwoven fabric of an organic fiber can be used. Not something. The method for producing the prepreg from the epoxy resin composition is not particularly limited, for example, after impregnating a resin varnish prepared by adjusting the viscosity of the epoxy resin composition with a solvent, It is obtained by heating and drying to obtain a semi-cured (B-staged) resin component. For example, it can be heated and dried at 100 to 200 ° C. for 1 to 40 minutes. Here, the amount of the resin in the prepreg is preferably 30 to 80% by mass.

In order to cure the prepreg, a method of curing a laminate generally used when manufacturing a printed wiring board can be used, but the method is not limited thereto. For example, when forming a laminate using prepreg, one or more prepregs are laminated, metal foil is arranged on one or both sides to form a laminate, and the laminate is heated and pressed to form a laminate. Become Here, as the metal foil, a single, alloy, or composite metal foil of copper, aluminum, brass, nickel, or the like can be used. Then, the prepreg is cured by heating and pressurizing the produced laminate, and a laminate can be obtained. At that time, the heating temperature is preferably 160 to 220 ° C., the pressure is preferably 50 to 500 N / cm ² , and the heating and pressing time is preferably 40 to 240 minutes, so that the desired cured product can be obtained. If the heating temperature is low, the curing reaction does not proceed sufficiently, and if the heating temperature is high, decomposition of the epoxy resin composition may start. In addition, if the pressure is low, bubbles may remain inside the obtained laminate, and the electrical characteristics may decrease.If the pressure is high, the resin flows before curing, and a cured product having a desired thickness is obtained. There is no fear. Further, if the heating and pressurizing time is short, the curing reaction may not proceed sufficiently, and if it is long, the epoxy resin composition in the prepreg may be thermally decomposed, which is not preferable. Further, a circuit may be formed on the laminate by an additive method, a subtractive method, or the like to obtain a printed wiring board.

  Further, a multilayer laminate can be obtained by using the laminate as an inner layer material. For example, first, a circuit is formed on the laminate by an additive method, a subtractive method, or the like, and the circuit surface is blackened with an acid solution to obtain an inner layer material. One or a plurality of the prepregs are arranged on one or both sides of the circuit forming surface of the obtained inner layer material, and a metal foil is arranged outside the prepreg to form a laminate. The laminate is heated and pressed to be integrally molded to form a multilayer laminate. For forming the insulating layer, an insulating adhesive sheet, a metal foil with resin, or the like can be used instead of the prepreg. Note that the same metal foil as that used for the laminate is used. Heat-press molding can be performed in the same manner as described above. Via holes and circuits are formed on the surface of the obtained multilayer laminate by an additive method or a subtractive method to obtain a multilayer printed wiring board. Further, by repeating the above method using this multilayer printed wiring board as an inner layer material, a further multilayer printed wiring board can be obtained.

  The epoxy resin composition can be cured by a method similar to a known epoxy resin composition to obtain a cured epoxy resin. As a method for obtaining a cured product, a method similar to a known epoxy resin composition can be used, and casting, injection, potting, dipping, drip coating, transfer molding, compression molding, and the like, resin sheet, resin For example, a method of forming a laminated plate by laminating in the form of an attached copper foil, prepreg, or the like, and curing by heating and pressurizing is preferably used. The curing temperature at that time is usually in the range of 100 to 300 ° C., and the curing time is usually about 1 to 5 hours.

  When an epoxy resin composition is prepared, a laminate is formed, and then cured by heating to form a laminate, the epoxy resin cured product can exhibit excellent heat resistance and flame retardancy.

  The present invention will be specifically described with reference to Examples and Comparative Examples, but the present invention is not limited to these. Unless otherwise specified, "parts" represents parts by mass, and "%" represents% by mass. The measurement was performed by the following methods.

  Epoxy equivalent: Measured in accordance with JIS K 7236 standard, and the unit was represented by “g / eq.”. Specifically, using an automatic potentiometric titrator (COM-1600ST, manufactured by Hiranuma Sangyo Co., Ltd.), using chloroform as a solvent, adding a brominated tetraethylammonium acetic acid solution, and adding a 0.1 mol / L perchloric acid-acetic acid solution Was titrated.

  Softening point: Measured according to JIS K 7234 standard, ring and ball method. Specifically, an automatic softening point apparatus (ASP-MG4, manufactured by Meitec Co., Ltd.) was used.

GPC measurement:. Use body (manufactured by Tosoh Corporation, column HLC-8220GPC (manufactured by Tosoh _Corporation, TSKgelG4000H _XL, TSKgelG3000H _XL, those having a TSKgelG2000H _XL) in series, column temperature was 40 ° C. Further, The eluent used was tetrahydrofuran (THF), the flow rate was 1 mL / min, the detector used was a differential refractive index detector, and the measurement sample was 0.1 g of a sample dissolved in 10 mL of THF. For data processing, GPC-8020 model II version 6.00 manufactured by Tosoh Corporation was used, and n = 0 component amount and n = 5 or more component amount were calculated from the obtained chromatogram. , Standard monodisperse polystyrene (manufactured by Tosoh Corporation, A-500, A 1000, A-2500, A-5000, F-1, F-2, F-4, F-10, F-20, F-40, F-80, F-128) The molecular weight (Mn), the weight average molecular weight (Mw), and the degree of dispersion (Mw / Mn) were measured.

  Glass transition temperature: IPC-TM-650 2.4.25. DSC · Tgm (with respect to the tangent line between the glass state and the rubber state) when the measurement was performed with a differential scanning calorimeter (EXSTAR6000 DSC6200, manufactured by Hitachi High-Tech Science Co., Ltd.) at a temperature rise of 20 ° C./min. (The middle temperature of the mutation curve).

  Flame retardancy: Evaluated by the vertical method according to UL94. The evaluation was described by V-0, V-1, and V-2.

  Copper foil peel strength and interlayer adhesive strength: Measured according to JIS C 6481 standard, and interlayer adhesive strength was measured by peeling between the seventh and eighth layers.

[Epoxy resin]
A1: Biphenol aralkyl type epoxy resin obtained in Synthesis Example 2 A2: Triphenol methane type epoxy resin (Nippon Kayaku Co., Ltd., EPPN-501H, epoxy equivalent 166)
A3: phosphorus-containing epoxy resin (FX-1225, epoxy equivalent 318, phosphorus content 2.5%, manufactured by Nippon Steel & Sumikin Chemical Co., Ltd.)
A4: Phosphorus-containing epoxy resin (manufactured by Nippon Steel & Sumikin Chemical Co., Ltd., YDFR-1320, epoxy equivalent: 763, phosphorus content: 5.0%)

[Curing agent]
B1: Phenol novolak resin (manufactured by Aika Kogyo Co., Ltd., Shaunol BRG-557, phenolic hydroxyl equivalent weight 105, softening point 80 ° C.)
B2: Dicyandiamide (manufactured by Nippon Carbide Industry Co., Ltd., DICY, active hydrogen equivalent 21)
B3: Phenol resin (manufactured by Gunei Chemical Co., Ltd., resin top TPM-100, phenol hydroxyl equivalent 98, softening point 108 ° C)

[Curing accelerator]
C1: 2-ethyl-4-methylimidazole (Curesol 2E4MZ, manufactured by Shikoku Chemicals Co., Ltd.)

Synthesis Example 1
A reaction apparatus equipped with a stirrer, a thermometer, a nitrogen inlet tube, and a cooling tube was charged with 246 parts of 4,4'-biphenol, 380 parts of diethylene glycol dimethyl ether, and 133 parts of 4,4'-bischloromethylbiphenyl, and the nitrogen gas flow was started. Under agitation, the temperature was raised to 170 ° C. and reacted for 2 hours. After the reaction, the entire amount of diethylene glycol dimethyl ether was distilled off under reduced pressure, 311 parts of toluene and 104 parts of methyl isobutyl ketone were charged and mixed by stirring. After cooling to room temperature, the unreacted raw material 4,4′-biphenol precipitated was filtered. After separately removing, toluene and methyl isobutyl ketone were distilled off to obtain 187 parts of a biphenylaralkyl-type phenol resin. The phenolic hydroxyl equivalent was 155 and the softening point was 130 ° C.

Synthesis Example 2
In a reactor equipped with a stirrer, a thermometer, a nitrogen inlet tube, and a cooling tube, 127 parts of the biphenylaralkyl-type phenol resin obtained in Synthesis Example 1 was put, and 448 parts of epochlorohydrin and 67 parts of diethylene glycol dimethyl ether were added. To 60 ° C. Under a reduced pressure of 110 mmHg, 64 parts of a 49% aqueous sodium hydroxide solution was added dropwise over 4 hours while maintaining the temperature at 58 to 62 ° C. During this time, epichlorohydrin was azeotroped with water, and the distilled water was sequentially removed from the system. After completion of the reaction, epichlorohydrin was recovered at 5 mmHg and 180 ° C., and 560 parts of toluene was added to dissolve the product. 180 parts of water was added to dissolve the salt by-produced, and the mixture was allowed to stand, and the lower layer of salt solution was separated and removed. After neutralization with a phosphoric acid aqueous solution, the resin solution was washed with water until the washing solution became neutral, and filtered. The mixture was heated to 180 ° C. under a reduced pressure of 5 mmHg, and toluene was distilled off to obtain 95 parts of a biphenylaralkyl-type epoxy resin (A1). Epoxy equivalent is 218, softening point is 97 ° C., n = 0 component is 4.3 area%, n = 5 component or more is 30.5 area%, Mn is 1440, Mw is 3200, Mw / Mn is 2.22. there were.

Example 1
10 parts of A1, 90 parts of A3, 35 parts of B1 and 0.05 part of C1 were mixed and dissolved in a mixed solvent prepared with MEK, propylene glycol monomethyl ether, and N, N-dimethylformamide to form an epoxy resin composition I got a varnish. The obtained epoxy resin composition varnish was impregnated into a glass cloth (WEA 7628 XS13, 0.18 mm thick, manufactured by Nitto Boseki Co., Ltd.). The impregnated glass cloth was dried in a hot air circulating oven at 150 ° C. for 9 minutes to obtain a prepreg. The obtained eight prepregs and copper foil (3EC-III, manufactured by Mitsui Mining & Smelting Co., Ltd., thickness 35 μm) are stacked on top and bottom, and 2 MPa vacuum press is performed under a temperature condition of 130 ° C. × 15 minutes + 190 ° C. × 80 minutes A laminate having a thickness of 1.6 mm was obtained. Table 1 shows the results of the glass transition temperature, copper foil peel strength, interlayer adhesive strength, and flame retardancy of the laminate.

Examples 2 to 7
A1 to A4 as an epoxy resin, B1 to B3 as a curing agent, and C1 as a curing accelerator were blended in the blending amounts (parts) shown in Table 1, and the same operation as in Example 1 was performed. I got At this time, the amount of the curing accelerator used was such that the varnish gel time could be adjusted to about 300 seconds. The same test as in Example 1 was performed, and the results are shown in Table 1. In addition, the phosphorus content in the table is a value as an epoxy resin composition.

Comparative Examples 1 to 8
A2 to A4 as an epoxy resin, B1 to B3 as a curing agent, and C1 as a curing accelerator were blended in the blending amounts (parts) shown in Table 2, and the same operation as in Example 1 was performed. I got The same test as in Example 1 was performed, and the results are shown in Table 2.

As is apparent from these results, an epoxy resin composition using a biphenylaralkyl-type epoxy resin and a phosphorus-containing epoxy resin provides an epoxy resin composition having both high heat resistance and flame retardancy.

Claims (5)

An epoxy resin composition comprising an epoxy resin and a curing agent as essential components, wherein the epoxy resin comprises a biphenylaralkyl type epoxy resin represented by the following general formula (1) and a phosphorus-containing epoxy resin. Resin composition.

(Here, n is the number of repetitions and represents a number of 0 or more, and the average value is a number of 1.3 to 20, and R ¹ , R ^2, and R ³ each independently represent a hydrogen atom or a carbon atom. ~ 8 hydrocarbon groups.)   The phosphorus-containing epoxy resin has an epoxy equivalent of 200 to 1000 g / eq. The epoxy resin composition according to claim 1, wherein the phosphorus content is 1.0 to 6.0% by mass.   A prepreg comprising the epoxy resin composition according to claim 1.   A laminate comprising the epoxy resin composition according to claim 1. A printed wiring board, comprising the epoxy resin composition according to claim 1.