CN112898738A

CN112898738A - Epoxy resin composition, prepreg, laminate, printed wiring board, and cured product using same

Info

Publication number: CN112898738A
Application number: CN202011374588.9A
Authority: CN
Inventors: 佐藤洋
Original assignee: Nippon Steel and Sumikin Chemical Co Ltd
Current assignee: Nippon Steel Chemical and Materials Co Ltd
Priority date: 2019-12-04
Filing date: 2020-11-30
Publication date: 2021-06-04
Anticipated expiration: 2040-11-30
Also published as: JP2021088656A; TW202130733A; JP7387413B2; CN112898738B; KR20210070206A

Abstract

The invention provides an epoxy resin composition, a prepreg, a laminated plate, a printed circuit board and a cured product using the same, which have excellent dielectric properties, and further have excellent heat resistance and flame retardance with Tg of more than 200 ℃. The epoxy resin composition comprises a phosphorus-containing epoxy resin, an oxazine resin, and an alicyclic structure-containing phenol resin, and has a phosphorus content of 0.5-1.8%, wherein the oxazine resin has an oxazine equivalent of 230g/eq or more, the phosphorus-containing epoxy resin is a product obtained from a novolak-type epoxy resin having a ratio (L/H) of heptanuclear bodies (H) or more to trinuclear bodies (L) of 0.6-4.0 in GPC measurement, and an average number of functional groups (Mn/E) of 3.8-4.8, and a phosphorus compound represented by general formula (1) and/or general formula (2).

Description

Epoxy resin composition, prepreg, laminate, printed wiring board, and cured product using same

Technical Field

The present invention relates to an epoxy resin composition such as a copper-clad laminate, a film material, and a resin-coated copper foil used for manufacturing an electronic circuit board, a flame-retardant epoxy resin composition using a phosphorus-containing epoxy resin having flame retardancy, such as a sealing material, a molding material, an injection molding material, an adhesive, an electrical insulating material, and a coating material used for an electronic component, and a copper-clad laminate, a prepreg, a laminate, a printed circuit board, and a cured product using the same.

Background

In recent years, electronic devices have been made flame retardant, and in consideration of environmental impact, attempts have been made to suppress toxic gases generated during combustion of the electronic devices. Flame retardancy using an organic phosphorus compound, that is, halogen-free flame retardancy has been realized since flame retardancy using a halogen-containing compound typified by a brominated epoxy resin has been conventionally used. These applications are not limited to electronic circuit boards, but are generally widely used and recognized for phosphorus flame retardancy, and the same applies to the field of epoxy resins for circuit boards.

As a specific representative example of epoxy resins to which such phosphorus flame retardancy is imparted, it is proposed to use organic phosphorus compounds 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 (9, 10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide, DOPO) with epoxy resins at a predetermined molar ratio.

Patent document 2 discloses a phosphorus-containing epoxy resin composition obtained by reacting an organophosphorus compound having active hydrogen, which is obtained by reacting an organophosphorus compound having one active hydrogen bonded to a phosphorus atom, such as DOPO, with a quinone compound, and further reacting an epoxy resin containing a novolak epoxy resin with the organophosphorus compound.

Patent document 3 discloses a phosphorus-containing epoxy resin obtained by reacting an organic phosphorus compound, a trifunctional epoxy resin, a bifunctional epoxy resin, and a bifunctional phenol compound at a predetermined mixing ratio.

Patent document 4 discloses a curable resin composition using, as a main agent, a phosphorus atom-containing epoxy resin obtained by reacting and oligomerizing a phosphorus atom-containing compound and an o-hydroxybenzaldehyde compound, and reacting a phosphorus atom-containing oligomer obtained by reacting a polyfunctional epoxy resin with the epoxy resin.

In the above-mentioned patent documents 1 to 4, the cured product can obtain flame retardancy and a glass transition temperature (Tg) equivalent to those of an FR-4 substrate, and in recent years, flame retardancy and a heat resistance, i.e., a glass transition temperature (Tg) of FR-5 or more are required at higher temperatures in the progress of high-density mounting of substrates or mounting of the substrate from an automobile cabin to the vicinity of a hood driving portion.

In these curing techniques for phosphorus-containing epoxy resins, Dicyanodiamide (DICY) containing nitrogen is effective in compensating for flame retardancy, and is generally used as a good curing agent. However, it is known that a cured product using the phenol curing agent has poor water absorption and heat resistance reliability as compared with a cured product using the phenol curing agent, and in particular, a problem is that solder heat resistance after a Pressure Cooker Test (PCT) for laminate application is deteriorated.

The conventional phosphorus-containing epoxy resin generally has poor compatibility with a polyfunctional phenol curing agent such as phenol novolak, and tends to have low heat resistance (glass transition temperature: Tg).

As one method for obtaining higher heat resistance, it is considered effective to use an oxazine resin for the hardener. For example, patent document 5 discloses a resin composition containing an epoxy resin, a benzoxazine resin, a dicyclopentadiene-phenol resin, and an amine-based curing agent at a predetermined blending ratio.

However, in the resin composition of patent document 5, the flame retardancy of the cured product is insufficient, and therefore, in order to compensate for this, it is necessary to use a flame-retardant additive in combination. The addition of the flame retardant is essential to significantly reduce the heat resistance in the resin formulation of the substrate which is required to have extremely high heat resistance of FR-5 or more.

Therefore, a new epoxy resin composition capable of simultaneously securing various properties such as heat resistance, dielectric properties and flame retardancy has been demanded.

[ Prior art documents ]

[ patent document ]

[ patent document 1] Japanese patent application laid-open No. Hei 11-166035

[ patent document 2] Japanese patent laid-open No. Hei 11-279258

[ patent document 3] Japanese patent application laid-open No. 2002-206019

[ patent document 4] Japanese patent laid-open No. 2013-035921

[ patent document 5] Japanese patent laid-open publication No. 2017-20011

Disclosure of Invention

[ problems to be solved by the invention ]

The present invention provides a non-halogen flame-retardant epoxy resin composition which maintains high heat resistance with Tg of more than 200 ℃, simultaneously has low water absorption and low dielectric constant, and a prepreg, a copper-clad laminate and a printed circuit board using the same.

[ means for solving problems ]

The present inventors have made extensive studies to overcome these problems, and as a result, they have found that a novolak-type epoxy resin, which is a raw material of a phosphorus-containing epoxy resin, has a high effect of improving heat resistance and flame retardancy by paying attention to the ratio of a polymer component having seven or more nuclei to a trimer and the average number of functional groups and determining them, and that a combination of a specific oxazine resin and an alicyclic structure-containing phenol resin as a curing agent for the epoxy resin can achieve both low dielectric characteristics, water resistance (low water absorption) and flame retardancy while maintaining extremely high heat resistance.

That is, the present invention is an epoxy resin composition comprising (A) a phosphorus-containing epoxy resin, (B) an oxazine resin, and (C) an alicyclic structure-containing phenol resin, characterized in that,

(B) the oxazine resin has an oxazine equivalent of 230g/eq or more, and (A) the phosphorus-containing epoxy resin is a product obtained from a novolac-type epoxy resin having a content of trinuclears (area%), a content of L) relative to heptanuclei (area%, H) as measured by gel permeation chromatography (L/H) in the range of 0.6 to 4.0, an average number of functional groups (Mn/E) obtained by dividing the number-average molecular weight (Mn) by the epoxy equivalent (E) as a standard polystyrene equivalent, and a phosphorus compound represented by general formula (1) and/or general formula (2) in the range of 0.5 to 1.8 mass%.

[ solution 1]

In the general formula (1) and the general formula (2), R¹And R²Each independently represents a C1-20 hydrocarbon group which may have a hetero atom, may be different or the same, and may be linear, branched or cyclic, or may form R¹And R²A bonded cyclic structure. k1 and k2 are each independently 0 or 1. A is an aryltriyl group having 6 to 20 carbon atoms.

In addition, the conditions for Gel Permeation Chromatography (GPC) were determined by using a column (TSKgelG 4000H, manufactured by Tosoh corporation, HLC-8220GPC) serially included in a bulk (manufactured by Tosoh corporation, HLC-8220GPC)_xL、TSKgelG3000H_xL、TSKgelG2000H_xL) The column temperature was set to 40 ℃. In addition, Tetrahydrofuran (THF) was used as an eluent, and a differential Refractometer (RI) detector was used as a detector, with a flow rate of 1 mL/min. The measurement sample was obtained by dissolving 0.05g of the sample in 10mL of THF in 50. mu.L and filtering the solution with a microfilter (microfilter). The number average molecular weight (Mn) of the novolak type epoxy resin and the content (area%) of each core body were measured by using a standard polystyrene calibration curve.

The oxazine resin (B) may be selected from compounds of the formula represented by the following general formula (3).

[ solution 2]

In the general formula (3), R³Each independently is an aromatic ring radical, R⁴Are independently hydrogen atom or C1-20 alkyl, and can form two R in the same benzene ring⁴A linked ring structure. R⁵Each independently represents a hydrogen atom or a hydrocarbon group having 1 to 20 carbon atoms. Y is-O-or-N (R)⁶)-，R⁶Is a hydrocarbon group having 1 to 20 carbon atoms. Z is-CO-or-SO₂-。

The alicyclic structure-containing phenol resin (C) used in the epoxy resin composition may be selected from compounds having a structural formula represented by the following general formula (4).

[ solution 3]

In the formula (4), T is an aliphatic cyclic hydrocarbon group, X is an aromatic ring group selected from a benzene ring, a naphthalene ring, a biphenyl ring and a diphenyl ring, and the aromatic ring group may have an alkyl group having 1 to 6 carbon atoms, an alkoxy group having 1 to 6 carbon atoms, an aryl group having 6 to 10 carbon atoms, an aryloxy group having 6 to 10 carbon atoms, an arylalkyl group having 7 to 12 carbon atoms or an arylalkyloxy group having 7 to 12 carbon atoms; i is an integer of 1-3; n is a number of 1 to 10 on the average.

The present invention is a cured product obtained by curing the epoxy resin composition, and a prepreg, a laminate, or a printed wiring board using the epoxy resin composition.

[ Effect of the invention ]

The epoxy resin composition of the present invention can achieve both extremely high heat resistance and flame retardancy, which cannot be achieved by conventional epoxy resin compositions, and further provides a cured product having low dielectric characteristics and low water absorption.

Drawings

FIG. 1 shows a GPC chart of the novolak type epoxy resin obtained in Synthesis example 3.

FIG. 2 shows a GPC chart of a general-purpose phenol novolak type epoxy resin.

Detailed Description

Hereinafter, embodiments of the present invention will be described in detail.

The epoxy resin composition of the present invention is a non-halogen flame-retardant epoxy resin composition containing (a) a phosphorus-containing epoxy resin, (B) an oxazine resin, and (C) an alicyclic structure-containing phenol resin as essential components, and has a phosphorus content in the range of 0.5 to 1.8 mass%. The phosphorus content in the epoxy resin composition as used herein means a ratio of organic components excluding the solvent and the inorganic filler from the epoxy resin composition. If the phosphorus content is less than 0.5 mass%, flame retardancy may be insufficient, and if the phosphorus content exceeds 1.8 mass%, heat resistance having a Tg of 200 ℃. The phosphorus content is preferably in the range of 0.6 to 1.6% by mass, and more preferably in the range of 0.8 to 1.3% by mass.

(A) The phosphorus-containing epoxy resin is obtained by reacting a novolak epoxy resin having a specific molecular weight distribution and a specific average number of functional groups with a phosphorus compound represented by the general formula (1) and/or a phosphorus compound represented by the general formula (2). However, in the case where only the phosphorus compound of the general formula (2) is used alone, it is preferable to increase the ratio of the phosphorus compound of the general formula (1) in order to lower the heat resistance of the composition. Specifically, the molar ratio of the phosphorus compound of the general formula (1) to the phosphorus compound of the general formula (2) is preferably 99: 1 to 75: 25, and more preferably 95: 5 to 85: 15. When the amount is within the above range, the phosphorus-containing epoxy resin composition is preferably used in view of the treatment of viscosity or the like which affects impregnation properties into the glass cloth.

In addition, when the phosphorus compound of the general formula (2) is DOPO and the phosphorus compound of the general formula (1) is a reaction product of DOPO and Naphthoquinone (NQ), for example, when the molar ratio NQ/DOPO is 0.50, the molar ratio of the phosphorus compound of the general formula (1) to the phosphorus compound of the general formula (2) corresponds to 50: 50, and when the molar ratio NQ/DOPO is 0.99, it corresponds to 99: 1, in terms of the raw material molar ratio.

As the phosphorus compound, it is necessary to use the phosphorus compound represented by the above general formula (1) or general formula (2), and it may be used alone or in combination.

In the general formula (1) or the general formula (2), R¹And R²The alkyl groups may be different or the same and may be linear, branched or cyclic. In addition, R¹And R²May be bonded to form a ring structure. Particularly preferred is an aromatic ring group such as a benzene ring. At R¹And R²When the aromatic ring group is used, the aromatic ring group may have an alkyl group having 1 to 8 carbon atoms, an alkoxy group having 1 to 8 carbon atoms, a cycloalkyl group having 5 to 8 carbon atoms, an aryl group having 6 to 10 carbon atoms, an aralkyl group having 7 to 11 carbon atoms, an aryloxy group having 6 to 10 carbon atoms or an aralkyloxy group having 7 to 11 carbon atoms as a substituent. Examples of the hetero atom include an oxygen atom and the like, which may be contained in a hydrocarbon chain or a carbon atom constituting a hydrocarbon ring.

k1 and k2 are each independently 0 or 1.

A is a trivalent aromatic hydrocarbon group (aryltriyl) having 6 to 20 carbon atoms. Preferably a benzene ring group or a naphthalene ring group. The aromatic hydrocarbon group may have an alkyl group having 1 to 6 carbon atoms, an alkoxy group having 1 to 6 carbon atoms, an aryl group having 6 to 10 carbon atoms, an aryloxy group having 6 to 10 carbon atoms, an aralkyl group having 7 to 12 carbon atoms, or an aralkyloxy group having 7 to 12 carbon atoms as a substituent.

First, when a phosphorus compound represented by the above general formula (2) used as a raw material is exemplified, there can be mentioned: dimethyl phosphine oxide, diethyl phosphine oxide, dibutyl phosphine oxide, diphenyl phosphine oxide, dibenzyl phosphine oxide, cyclooctylene phosphine oxide, cresyl phosphine oxide, bis (methoxyphenyl) phosphine oxide, etc., or phenyl phenylphosphinate, ethyl phenylphosphinate, tolyl phenylphosphinate, benzyl phenylphosphinate, etc., or DOPO, 8-methyl-9, 10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide, 8-benzyl-9, 10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide, 8-phenyl-9, 10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide, 2, 6, 8-tributyl-9, 10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide, 6, 8-dicyclohexyl-9, 10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide, etc., or diphenyl phosphonate, ditolyl phosphonate, dibenzyl phosphonate, 5-dimethyl-1, 3, 2-dioxaphosphaphane, etc., but is not limited thereto. These phosphorus compounds may be used alone or in combination of two or more.

Further, when a phosphorus compound represented by the above general formula (1) is exemplified as a raw material, there can be mentioned: 10- (2, 5-dihydroxyphenyl) -10H-9-oxa-10-phosphaphenanthrene-10-oxide (DOPO-HQ), 10- [2- (dihydroxynaphthyl) ] -9, 10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide (DOPO-NQ), diphenylphosphinohydroquinone, diphenylphosphino-1, 4-dioxynaphthalene, 1, 4-cyclooctylenephosphino-1, 4-benzenediol, 1, 5-cyclooctylenephosphino-1, 4-benzenediol, and the like. These phosphorus compounds may be used alone or in combination of two or more, but are not limited thereto.

The novolak type epoxy resin used as a raw material of the phosphorus-containing epoxy resin (a) together with the phosphorus compound is generally a polyfunctional novolak type epoxy resin obtained by reacting a novolak type phenol resin, which is a condensation reaction product of a phenol and an aldehyde, with an epihalohydrin such as epichlorohydrin, and is represented by the following general formula (5).

Examples of the phenols to be used include: phenol, cresol, ethylphenol, butylphenol, styrenated phenol, cumylphenol, naphthol, catechol, resorcinol (resorcinol), naphthalenediol, bisphenol a and the like, and examples of the aldehydes include: formalin, formaldehyde, hydroxybenzaldehyde, salicylaldehyde (salicylaldehyde), and the like. In addition, aralkyl type phenol resins using xylylene glycol, dichloroxylylene, bischloromethylnaphthalene, bischloromethylbiphenyl, or the like in place of aldehydes also correspond to novolac type phenol resins in the present invention.

[ solution 4]

In the general formula (5), W is an aromatic ring group selected from a benzene ring, a naphthalene ring, a biphenyl ring or a diphenyl ring, and the aromatic ring group may have an alkyl group having 1 to 6 carbon atoms, an alkoxy group having 1 to 6 carbon atoms, an aryl group having 6 to 10 carbon atoms, an aryloxy group having 6 to 10 carbon atoms, an aralkyl group having 7 to 12 carbon atoms or an aralkyloxy group having 7 to 12 carbon atoms.

U is a crosslinking group represented by the following formula (5a) or (5 b). And may be a divalent aliphatic cyclic hydrocarbon group.

j is independently an integer of 1 to 3, represents the number of hydroxyl groups of each aromatic ring, and is preferably 1 or 2.

m is a number of 1 to 10 in average, preferably 1 to 5.

[ solution 5]

In the above formulae (5a) and (5b), R⁸、R⁹、R¹⁰And R¹¹Each independently represents a hydrogen atom or a hydrocarbon group having 1 to 6 carbon atoms. B is an aromatic ring group selected from a benzene ring, a naphthalene ring or a biphenyl ring, and the aromatic ring group may have an alkyl group having 1 to 6 carbon atoms, an alkoxy group having 1 to 6 carbon atoms, an aryl group having 6 to 10 carbon atoms, an aryloxy group having 6 to 10 carbon atoms, an arylalkyl group having 7 to 12 carbon atoms, or an arylalkoxy group having 7 to 12 carbon atoms as a substituent.

When U is a divalent aliphatic cyclic hydrocarbon group, the number of carbon atoms is preferably 5 to 15, more preferably 5 to 10. Examples of the divalent aliphatic cyclic hydrocarbon group include divalent aliphatic cyclic hydrocarbon groups derived from unsaturated cyclic aliphatic hydrocarbon compounds such as dicyclopentadiene, tetrahydroindene, 4-vinylcyclohexene, 5-vinylnorborn-2-ene, α -pinene, β -pinene and limonene, and cycloalkylene groups such as trimethylcyclohexylene, tetramethylcyclohexylene and cyclododecylene.

Specific examples of the general novolak type epoxy resin include: phenol novolac type epoxy resins (e.g., Epotohto YDPN-638 (manufactured by Nippon chemical & materials Co., Ltd.), jER152, jER154 (manufactured by Mitsubishi chemical Co., Ltd.), Epicolon (EPICLON) N-740, N-770, N-775 (manufactured by Diesen chemical Co., Ltd.), etc.), cresol novolac type epoxy resins (e.g., Epotohto YDCN-700 series (manufactured by Diesen chemical & materials Co., Ltd.), Epicolon (EPICLON) N-660, N-665, N-670, N-673, N-695 (manufactured by Diesen chemical Co., Ltd.), EOCN-1020, EOCN-102S, EOCN-104S (manufactured by Nippon chemical Co., Ltd.), etc.), alkyl novolac type epoxy resins (e.g., epotohto ZX-1071T, ZX-1270, ZX-1342 (manufactured by Nippon chemical & materials Co., Ltd.) and the like), an aromatic modified phenol novolak type epoxy resin (for example, Epotohto ZX-1247, GK-5855, TX-1210, YDAN-1000 (manufactured by Nippon chemical & materials Co., Ltd.) and the like), a bisphenol novolak type epoxy resin, a naphthol novolak type epoxy resin (for example, Epotohto ZX-1142L (manufactured by Nippon chemical & materials Co., Ltd.) and the like), a β -naphthol aralkyl type epoxy resin (for example, ESN-155, ESN-185V, ESN-175 (manufactured by Nippon chemical & materials Co., Ltd.) and the like), a naphthalenediol aralkyl type epoxy resin (for example, ESN-355, ESN-375 (manufactured by Nippon Tekken chemical & materials Co., Ltd.) or the like), α -naphthol aralkyl type epoxy resins (for example, ESN-475V, ESN-485 (manufactured by Nippon Tekken chemical & materials Co., Ltd.) or the like), biphenyl aralkyl phenol type epoxy resins (for example, NC-3000H (manufactured by Nippon Tekken Co., Ltd.) or the like), trihydroxyphenyl methane type epoxy resins (for example, EPPN-501, EPPN-502 (manufactured by Nippon Tekken chemical Co., Ltd.) or the like), dicyclopentadiene type epoxy resins (for example, Ainbrake (EPICLON) HP7200, HP-7200H (manufactured by Diezo (DIC) Co., Ltd.) or the like), or the like. However, these commercially available novolak-type epoxy resins generally do not have a specific molecular weight distribution that is characteristic of the novolak-type epoxy resin used in the present invention, and the average number of functional groups is out of the range.

In order to obtain a novolak-type epoxy resin having a specific molecular weight distribution and a specific average number of functional groups used in the present invention, a novolak-type phenol resin obtained by reacting a phenol with an aldehyde in the presence of an acid catalyst is used as a starting material thereof. These reaction methods are conventional methods obtained by the production methods shown in, for example, Japanese patent laid-open Nos. 2002-194041, 2007-126683, and 2013-107980, and are not particularly limited.

The novolak-type phenol resin as the starting material obtained is adjusted by removing a low molecular weight centered on the dinuclear bodies by various methods such as distillation or reducing the content to 10 area% or less, and then condensing with aldehydes again in the presence of an acid catalyst, thereby reducing the dinuclear bodies and increasing the ratio of heptanuclear bodies or more. Since the novolak type epoxy resin is epoxidized while reflecting the molecular weight distribution of the novolak type phenol resin, the content of each core body in the obtained novolak type epoxy resin is also adjusted in the same manner.

In the present specification, the "content ratio" of each core body of the novolak type epoxy resin is "area%" measured by GPC, and may be expressed as a content ratio or an area%. The content of heptakaryons or more and the content of trinuclears may be simply expressed as "H" and "L", respectively. Here, in the novolac epoxy resin represented by the general formula (6), m is 2 in the case of the three core bodies, and m is 6 or more in the case of the seven core bodies or more.

In the production of a novolak-type phenol resin, the molar ratio of a phenol to an aldehyde is adjusted by adjusting the molar ratio of the phenol to 1 mole of the aldehyde. Generally, when the molar ratio of the phenol used is large, a large amount of dinuclears and then a large amount of trinuclears are produced, and as the molar ratio of the phenol used becomes smaller, a large amount of high molecular weight as a polynuclear product is produced, whereas the dinuclears and trinuclears are reduced.

In general novolak-type phenol resins in which low molecules are not removed, when the number of functional groups is increased, the degree of condensation is generally increased by decreasing the molar ratio of phenol to 1 mole of aldehyde. In the case of the above-mentioned production method, the dispersion (Mw/Mn) of the molecular weight distribution of the obtained novolak-type phenol resin becomes broad, and the value of the number average molecular weight (Mn) becomes low due to the influence of the amount of the residual dinuclear bodies. On the other hand, the increase in the content (area%) of heptakaryons or more measured by GPC becomes significantly large. In addition, when the novolak-type phenol resin is epoxidized, the epoxy equivalent (E) also becomes high, and therefore the value of the average number of functional groups (Mn/E) tends to become small, and it is not suitable as an epoxy resin aimed at high heat resistance.

Regarding flame retardancy, since the dinuclear bodies of the novolak type epoxy resin are bifunctional, the participation in the crosslinked structure in the cured product is weak, and there is a concern that the flame retardancy is adversely affected by the level of thermal decomposition at the time of ignition. Therefore, as one of the systems for promoting flame retardancy, it is effective to remove low molecules centered on the nuclei and recondense them.

On the other hand, as another method for promoting flame retardancy, a method of suppressing the generation of combustible decomposed gas to the outside is also known. Therefore, it is preferable to suppress the elastic coefficient of the rubber-like region of the cured product at a high temperature to be low. However, it is known that, in a cured product having high heat resistance, the high crosslinking density tends to increase the high-temperature elastic coefficient, and the vicinity of nonflammable carbon formed after combustion becomes hard and brittle, thereby deteriorating flame retardancy.

Therefore, in view of the mechanism for promoting flame retardancy, many attempts have been made to achieve multifunctionalization by reducing dinuclears and also not excessively increasing polynuclear bodies, and as a result, it has been found that a method for achieving multifunctionalization by recondensation of a starting material mainly composed of a trinuclear body after reducing dinuclears is effective for flame retardancy. That is, by using a novolac-type epoxy resin in which the ratio (L/H) of the content (L) of the three core bodies to the content (H) of the seven or more core bodies is in the range of 0.6 to 4.0 as a raw material of the phosphorus-containing epoxy resin, the flame retardant effect can be sufficiently exhibited by the resin itself even if the amount of the phosphorus compound used is reduced.

When the phosphorus-containing epoxy resin obtained by the above method is used, the elasticity coefficient of a cured product of the phosphorus-containing epoxy resin composition in a high temperature region can be suppressed to be low, and the flame retardancy can be improved. Specifically, in the actual measurement using a dynamic viscoelasticity measuring apparatus (DMA: measurement conditions of a temperature rise rate of 2 ℃/minute and a frequency of 1 Hz), the value of the storage elastic coefficient stabilized at 220 ℃ or higher is decreased, whereby the combustion portion of the combustion test piece foams and extinguishment of the fire is promoted. The value of the elastic modulus is preferably adjusted to 150MPa or less, and more preferably adjusted to 50MPa or less. If the content of the heptanuclear bodies is excessively increased, the crosslinking density of the cured product increases, and the char around the burned part becomes hard and brittle, resulting in deterioration of flame retardancy.

In the novolak type epoxy resin which is a raw material of the phosphorus-containing epoxy resin used in the present invention, as a method for removing or reducing dinuclear bodies from a novolak type phenol resin which is a raw material thereof, a method using poor solubility of various solvents, a method of removing by dissolving in an alkaline aqueous solution, a method of removing by thin film distillation, and the like are conventional methods, and any of these separation methods can be used.

The novolak-type phenol resin from which dinuclear bodies are removed or reduced by the method described above is subjected to adjustment of molecular weight distribution by condensation with aldehydes again. As the recondensation method, the following method is available: dissolving the compound in an organic solvent such as toluene or isobutyl ketone, and then reacting the compound with aldehydes by an acid catalyst; or the same reaction may be carried out in a solvent-free molten state. The acid catalyst may be used singly or in combination of inorganic acids such as hydrochloric acid, sulfuric acid and boric acid, and organic acids such as oxalic acid, acetic acid, benzenesulfonic acid, p-toluenesulfonic acid, xylenesulfonic acid, p-phenolsulfonic acid, methanesulfonic acid and ethanesulfonic acid. In addition, the aldehydes can be used as they are. Examples thereof include formaldehyde, paraformaldehyde (paraformaldehyde), chloroacetaldehyde, dichloroacetaldehyde, bromoacetaldehyde, trioxane (trioxane), acetaldehyde (acetaldehyde), glyoxal (glyoxal), acrolein (acrolein), methacrolein (methacrolein), etc., and in the production of phenol novolak, formaldehyde and paraformaldehyde are preferable. In this case, the aldehyde may be used alone or as a mixture of two or more thereof. The method of charging the aldehyde and the like can be carried out by a method corresponding to the equipment, such as a method of charging the aldehyde and the like together with the raw material in the presence of an acid catalyst in a state including sufficient cooling equipment, or a method of separately charging the aldehyde and the raw material while confirming the heat generation state accompanying the progress of the reaction.

The amount of the aldehyde used for the recondensation is preferably 0.06 to 0.30 times the molar number obtained by dividing the charged amount of the novolak type phenol resin by the actual average molecular weight of the novolak type phenol resin, and in the case where the reaction is carried out more preferably 0.08 to 0.15 times, and further more preferably 0.10 to 0.12 times, the optimum core body as the novolak type epoxy resin can be adjusted. The "actual average molecular weight" herein means a molecular weight obtained by multiplying the area% of each nucleus body measured by GPC by each theoretical molecular weight and cumulatively averaging the results. When the amount is less than 0.06 times, the average number of functional groups of the phosphorus-containing epoxy resin is insufficient, and heat resistance of 200 ℃ or higher cannot be obtained. When the amount is more than 0.30 times, the average number of functional groups is excessively increased, and sufficient flame retardancy cannot be obtained due to high elasticity of the cured product.

The epoxidation of the novolak-type phenol resin obtained in the above manner can be carried out by an existing method. For example, the reaction can be carried out by using 3 to 5 times by mole of epihalohydrin with respect to the number of moles of hydroxyl groups of the novolak-type phenol resin, and adding a caustic soda aqueous solution dropwise thereto at 60 to 70 ℃ for 2 hours under a reduced pressure of 100to 200torr (13.3 to 26.7 kPa).

In the novolak type epoxy resin obtained by these methods, the ratio (L/H) of the area% of the three core bodies to the area% of the seven or more core bodies (H) is in the range of 0.6 to 4.0, and the average number of functional groups (Mn/E) obtained by dividing the number average molecular weight (Mn) by the epoxy equivalent (E) is in the range of 3.8 to 4.8 in a measurement using GPC.

When the (L/H) exceeds 4.0, the number of the trinucleus bodies increases, the average number of functional groups becomes less than 3.8, and the heat resistance of the cured product using the phosphorus-containing epoxy resin decreases, so that a Tg of 200 ℃ or higher cannot be obtained. On the other hand, when the (L/H) is less than 0.6, the number of heptanuclei or more increases and the number of binuclears decreases, so that the cured product becomes hard and brittle and the flame retardancy is greatly impaired. More preferably, the novolac epoxy resin has an L/H ratio of 1.0 to 3.0.

The reaction of the phosphorus compound represented by the general formula (1) and/or the general formula (2) with the novolak-type epoxy resin to obtain a phosphorus-containing epoxy resin is carried out by a conventional method. For example, as described in patent document 2, a method may be employed in which after the synthesis of general formulae (1) and (2), a novolac-type epoxy resin or the like is added and homogenized, and then triphenylphosphine or the like is added as a catalyst and reacted at 150 ℃.

In addition, a catalyst may be used in the reaction in order to shorten the time or lower the reaction temperature. The catalyst used is not particularly limited, and those commonly used in the synthesis of epoxy resins can be used. For example, various catalysts such as tertiary amines such as benzyldimethylamine, quaternary ammonium salts such as tetramethylammonium chloride, phosphines such as triphenylphosphine and tris (2, 6-dimethoxyphenyl) phosphine, phosphonium salts such as ethyltriphenylphosphonium bromide, imidazoles such as 2-methylimidazole and 2-ethyl-4-methylimidazole can be used, and these catalysts may be used alone or in combination of two or more. Further, the components may be divided into several parts and used.

The amount of the catalyst is not particularly limited, and is preferably 5% by mass or less, more preferably 1% by mass or less, and still more preferably 0.5% by mass or less, based on the phosphorus-containing epoxy resin (the total amount of the novolac-type epoxy resin and the phosphorus compound as raw materials). If the amount of the catalyst is large, the self-polymerization reaction of the epoxy group proceeds depending on the case, and therefore the resin viscosity becomes high, which is not preferable. When the pre-reacted epoxy resin is formed by stopping the reaction in the middle of the reaction, the reaction rate can be easily adjusted to 60% to 90% by setting the amount of the catalyst to 0.1% by mass or less.

When the phosphorus compound represented by the general formula (1) or (2) is reacted with a novolak-type epoxy resin, various epoxy resin modifiers may be used in combination as needed within a range not impairing the characteristics of the present invention. Examples of the modifier include: bisphenol a, bisphenol F, bisphenol AD, tetrabutylbisphenol a, hydroquinone, methylhydroquinone, dimethylhydroquinone, dibutylhydroquinone, resorcinol (resorcin), methylresorcinol, biphenol, tetramethylbiphenol, 4' - (9-fluorenylidene) diphenol, dihydroxynaphthalene, dihydroxydiphenyl ether, dihydroxydiphenylethylene, phenol novolak, cresol novolak, bisphenol a novolak, dicyclopentadiene phenol, phenol aralkyl, naphthol novolak, terpene phenol, heavy oil-modified phenol, brominated phenol novolak, and the like, or a polyphenol resin obtained by condensation reaction of various phenols with various aldehydes such as hydroxybenzaldehyde, crotonaldehyde, glyoxal, and the like, or aniline, phenylenediamine, toluidine, xylidine (xylidine), Amine compounds such as diethyltoluenediamine, diaminodiphenylmethane, diaminodiphenylethane, diaminodiphenylpropane, diaminodiphenylketone, diaminodiphenylsulfide, diaminodiphenylsulfone, bis (aminophenyl) fluorene, diaminodiethyldimethyldiphenylmethane, diaminodiphenylether, diaminobenzanilide (diaminobenzanilide), diaminobiphenyl, dimethyldiaminobiphenyl, biphenyltetramine, bisaminophenylanthracene, bisaminophenoxybenzene, bisaminophenoxyphenyl ether, bisaminophenoxybiphenyl, bisaminophenoxyphenyl sulfone, bisaminophenoxyphenyl propane, and diaminonaphthalene, but are not limited thereto. These epoxy resin modifiers may be used alone or in combination of two or more.

In addition, an inert solvent may be used for the reaction. Specifically, it is possible to use: examples of the solvent include various hydrocarbons such as hexane, heptane, octane, decane, dimethylbutane, pentene, cyclohexane, methylcyclohexane, benzene, toluene, xylene and ethylbenzene, various alcohols such as isopropyl alcohol, isobutyl alcohol, isoamyl alcohol and methoxypropanol, ethers such as diethyl ether, isopropyl ether, butyl ether, diisoamyl ether, methylphenyl ether, ethylphenyl ether, pentylphenyl ether, ethylbenzyl ether, dioxane, methylfuran and tetrahydrofuran, methyl cellosolve acetate, ethyl cellosolve acetate, ethylene glycol isopropyl ether, diethylene glycol dimethyl ether, methyl ethyl carbitol, propylene glycol monomethyl ether, dimethylformamide and dimethylsulfoxide.

As the (B) oxazine resin, various resins can be used if the oxazine equivalent is 230g/eq. The preferable range of the oxazine equivalent is 230g/eq to 500g/eq, more preferably 240g/eq to 400g/eq, further preferably 250g/eq to 380g/eq, and particularly preferably 260g/eq to 350g/eq. In addition to the oxazine resin having the structure of the above-described general formula (3), an oxazine resin having a structure of the following general formula (6) or general formula (7) is preferable. In order to further improve the heat resistance and flame retardancy of the cured product, an oxazine resin having a structure of the above general formula (3) is more preferable.

Specific examples of the oxazine resin include: examples of the benzoxazine compound include bisphenol a type benzoxazine compounds (for example, XU3560CH (manufactured by Huntsman corporation)), bisphenol S type benzoxazine compounds (for example, BS-BXZ (manufactured by mini-chem chemical industries, ltd.), phenolphthalein type benzoxazine compounds (for example, LMB6490 (manufactured by Huntsman corporation)) and the like), diaminodiphenyl sulfone type benzoxazine resins, phenol novolac type benzoxazine compounds (for example, YBZ-2213 (manufactured by ferrichemical & materials ltd.), but are not limited thereto.

[ solution 6]

In the general formula (3), the general formula (6) and the general formula (7), R³Preferably a phenyl group or a naphthyl group, and these aromatic ring groups may have an alkyl group having 1 to 6 carbon atoms, an alkoxy group having 1 to 6 carbon atoms, an aryl group having 6 to 10 carbon atoms, an aryloxy group having 6 to 10 carbon atoms, an aralkyl group having 7 to 12 carbon atoms or an aralkyloxy group having 7 to 12 carbon atoms as a substituent.

R⁴Each independently represents a hydrogen atom or a hydrocarbon group having 1 to 20 carbon atoms which may be linear, branched or cyclic, and two R groups may be present on the same benzene ring⁴A linked ring structure. At R⁴When the aromatic ring group is used, the aromatic ring group may have an alkyl group having 1 to 8 carbon atoms, an alkoxy group having 1 to 8 carbon atoms, a cycloalkyl group having 5 to 8 carbon atoms, an aryl group having 6 to 10 carbon atoms, an aralkyl group having 7 to 11 carbon atoms, an aryloxy group having 6 to 10 carbon atoms or an aralkyloxy group having 7 to 11 carbon atoms as a substituent.

R⁵Each independently represents a hydrogen atom or a C1-20 hydrocarbon group.

R⁷Are each independently-O-, -SO₂-、-C(CH₃)₂-、-CH(CH₃)-、-CH₂And substituted or unsubstituted tetrahydrodicyclopentadienyl.

V represents an aromatic ring group, preferably a phenylene group or a naphthylene group, and the aromatic ring group may have an alkyl group having 1 to 6 carbon atoms, an alkoxy group having 1 to 6 carbon atoms, an aryl group having 6 to 10 carbon atoms, an aryloxy group having 6 to 10 carbon atoms, an aralkyl group having 7 to 12 carbon atoms, or an aralkyloxy group having 7 to 12 carbon atoms as a substituent.

Y is-O-or-N (R)⁶)-，R⁶Is a hydrocarbon group having 1 to 20 carbon atoms.

Z is-CO-or-SO₂-。

Examples of the preferable oxazine resin having the structure of formula (3) include, but are not limited to, compounds represented by the following formulae (3a) to (31). Among these, (3a), (3b), (3c), (3d), (3g), (3h), (3i), (3j), (3k), and (31) are preferable, and (3a), (3c), (3d), (3g), (3h), (3i), (3j), (3k), and (31) are more preferable, and (3a), (3c), (3h), (3i), (3k), and (31) are even more preferable.

[ solution 7]

In the epoxy resin composition of the present invention, the blending amount of the (B) oxazine resin is preferably 10 to 80 parts by mass, more preferably 15 to 75 parts by mass, even more preferably 20 to 70 parts by mass, and particularly preferably 30 to 65 parts by mass, based on 100 parts by mass of the (a) phosphorus-containing epoxy resin. If the content of the added oxazine resin is within the above range, the cured product obtained from the resin composition of the present invention can attain a desired low dielectric loss value (Df). If the amount of the oxazine resin is less than 10 parts by mass, the desired low dielectric loss value may not be obtained, and if it exceeds 80 parts by mass, the heat resistance of the substrate produced from the resin composition may be deteriorated.

(C) The alicyclic structure-containing phenol resin is represented by the general formula (4).

In the general formula (4), T is a divalent aliphatic cyclic hydrocarbon group and is an essential structure.

W is an aromatic ring group selected from a benzene ring, a naphthalene ring, a biphenyl ring or a biphenyl structure, and the aromatic ring group may have an alkyl group having 1 to 6 carbon atoms, an alkoxy group having 1 to 6 carbon atoms, an aryl group having 6 to 10 carbon atoms, an aryloxy group having 6 to 10 carbon atoms, an arylalkyl group having 7 to 12 carbon atoms, or an arylalkoxy group having 7 to 12 carbon atoms.

i is independently an integer of 1 to 3, and represents the number of hydroxyl groups of each aromatic ring, and is preferably 1 or 2.

n is a number of 1 to 10 in average, preferably 1 to 5.

The number of carbon atoms of the divalent aliphatic cyclic hydrocarbon group is preferably 5 to 20, more preferably 5 to 12. The divalent aliphatic cyclic hydrocarbon group is a substituted or unsubstituted cycloalkyldiyl group or a condensed ring group thereof, preferably a condensed ring group obtained by condensing two or more aliphatic rings, and may have a substituent having 1 to 10 carbon atoms, and in the case of a monocyclic group, a 1, 1-cycloalkylene group (cycloalkyl-1, 1-diyl group) bonded to the same carbon is preferable.

The substituent having 1 to 10 carbon atoms includes an alkyl group having 1 to 10 carbon atoms, an aryl group having 6 to 10 carbon atoms, or an aralkyl group having 7 to 10 carbon atoms. The alkyl group having 1 to 10 carbon atoms may be linear, branched or cyclic, and examples thereof include: methyl group, ethyl group, propyl group, isopropyl group, n-butyl group, sec-butyl group, tert-butyl group, pentyl group, hexyl group, heptyl group, octyl group, nonyl group, decyl group, cyclohexyl group, methylcyclohexyl group, dimethylcyclohexyl group, cyclooctyl group and the like, but are not limited thereto. Examples of the aryl group having 6 to 10 carbon atoms include, but are not limited to, phenyl, tolyl, xylyl, ethylphenyl, and naphthyl. Examples of the aralkyl group having 7 to 10 carbon atoms include, but are not limited to, benzyl and α -methylbenzyl.

Examples of the divalent aliphatic cyclic hydrocarbon group include: cyclopentane-1, 1-diyl, cyclohexane-1, 1-diyl, cycloheptane-1, 1-diyl, cyclooctane-1, 1-diyl, cyclononane-1, 1-diyl, cyclodecane-1, 1-diyl, cycloundecane-1, 1-diyl, cyclododecane-1, 1-diyl, 2-methylcyclohexane-1, 1-diyl, 3-methylcyclohexane-1, 1-diyl, 4-methylcyclohexane-1, 1-diyl, 2-ethylcyclohexane-1, 1-diyl, 3-ethylcyclohexane-1, 1-diyl, 4-ethylcyclohexane-1, 1-diyl, 2-tert-butylcyclohexane-1, 1-diyl group, 3-tert-butylcyclohexane-1, 1-diyl group, 4-tert-butylcyclohexane-1, 1-diyl group, 2-phenylcyclohexane-1, 1-diyl group, 3-phenylcyclohexane-1, 1-diyl group, 4-phenylcyclohexane-1, 1-diyl group, 3, 5-trimethylcyclohexane-1, 1-diyl group, 3, 5, 5-tetramethylcyclohexane-1, 1-diyl group, 3-methylcyclohexane-1, 1-diyl group, 2-isopropyl-5-methylcyclohexane-1, 5-diyl group, and crosslinking agents represented by the following formulae (4a) to (41), but not limited thereto. The crosslinking agent represented by the following formulae (4a) to (41) may have a substituent having 1 to 6 carbon atoms.

Of these, 3, 5-trimethylcyclohexane-1, 1-diyl, 3, 5, 5-tetramethylcyclohexane-1, 1-diyl, cyclododecane-1, 1-diyl, (4a), (4b), (4c), (4d), (4e), (4f), (4h), (4j), (41) are more preferable, 3, 5-trimethylcyclohexane-1, 1-diyl, 3, 5, 5-tetramethylcyclohexane-1, 1-diyl, cyclododecane-1, 1-diyl, (4a), (4b), (4c), (4d), (4e), (4f) are still more preferable, and 3, 3, 5-trimethylcyclohexane-1, 1-diyl, Cyclododecane-1, 1-diyl, (4 c).

[ solution 8]

In the epoxy resin composition of the present invention, the amount of the alicyclic structure-containing phenol resin (C) blended is preferably 10 to 50 parts by mass, more preferably 15 to 45 parts by mass, and still more preferably 20 to 40 parts by mass, per 100 parts by mass of the phosphorus-containing epoxy resin (a). When the content of the alicyclic structure-containing phenol resin is within the above range, a cured product obtained from the resin composition can have a desired value of relative dielectric constant (Dk). If the alicyclic structure-containing phenol resin is less than 10 parts by mass, a desired relative dielectric constant value may not be obtained, and the heat resistance of the substrate may be deteriorated. If the amount exceeds 50 parts by mass, the heat resistance of the substrate made of the resin composition may be deteriorated.

The epoxy resin composition of the present invention may be used in combination with an epoxy resin other than the phosphorus-containing epoxy resin, if necessary. Examples of epoxy resins that can be used in combination include: a polyglycidyl ether compound, a polyglycidyl amine compound, a polyglycidyl ester compound, an alicyclic epoxy compound, another modified epoxy resin, and the like, but are not limited thereto, and these epoxy resins may be used alone or in combination of two or more. When the epoxy resin is used in combination, it is preferably 50% by mass or less, more preferably 30% by mass or less of the total epoxy resin. If the amount of the epoxy resin used in combination is too large, the effect of both heat resistance and flame retardancy may not be obtained.

Specific examples of the epoxy resin that can be used in combination include: bisphenol A-type epoxy resin, bisphenol F-type epoxy resin, tetramethylbisphenol F-type epoxy resin, hydroquinone-type epoxy resin, biphenyl-type epoxy resin, bisphenol fluorene-type epoxy resin, bisphenol S-type epoxy resin, disulfide-type epoxy resin, resorcinol-type epoxy resin, biphenyl aralkyl phenol-type epoxy resin, naphthalene diphenol-type epoxy resin, phenol novolac-type epoxy resin, aromatic modified phenol novolac-type epoxy resin, cresol novolac-type epoxy resin, alkyl novolac-type epoxy resin, bisphenol novolac-type epoxy resin, naphthol novolac-type epoxy resin, beta-naphthol aralkyl-type epoxy resin, dinaphthol aralkyl-type epoxy resin, alpha-naphthol aralkyl-type epoxy resin, triphenylmethane-type epoxy resin, dicyclopentadiene-type epoxy resin, alkanediol-type epoxy resin, aliphatic cyclic epoxy resin, Diaminodiphenylmethane tetraglycidyl amine, aminophenol type epoxy resins, urethane-modified epoxy resins, oxazolidone ring-containing epoxy resins, and the like, but are not limited thereto.

The epoxy resin composition of the present invention may be used in combination with a conventional curing agent within a range not impairing the effects. Examples of the curing agent that can be used in combination include the above-mentioned (C) phenolic resin curing agent other than the alicyclic structure-containing phenolic resin, and commonly used curing agents such as acid anhydride curing agent, amine curing agent, and other curing agents. Of these, dicyandiamide curing agents are preferable in terms of imparting heat resistance, and phenol resin curing agents are preferable in terms of imparting water absorption and long-term thermal stability.

The amount of the curing agent that can be used in combination is preferably 50 parts by mass or less, more preferably 25 parts by mass or less, and still more preferably 10 parts by mass or less, per 100 parts by mass of the alicyclic structure-containing phenol resin (C). The amount of blending can also be determined from other viewpoints. The active hydrogen group of the hardener is in the range of 0.2 to 1.5 mol based on 1mol of the epoxy group of the total epoxy resin in the epoxy resin composition. When the active hydrogen group is less than 0.2 mol or more than 1.5 mol based on 1mol of the epoxy group, the curing may be incomplete, and favorable cured physical properties may not be obtained. Preferably 0.3 to 1.5 moles, more preferably 0.5 to 1.5 moles, and still more preferably 0.8 to 1.2 moles.

The active hydrogen group 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 which generates an active hydrogen by hydrolysis or the like, or a functional group which exhibits a similar curing action), and specifically includes an acid anhydride group, a carboxyl group, an amino group, a phenolic hydroxyl group, and the like. Further, as for the active hydrogen group, 1 mole of carboxyl group or phenolic hydroxyl group was calculated to be 1 mole, and amino group (NH)₂) Is 2 moles. In the case where the active hydrogen group is not clear, the active hydrogen equivalent can be determined by measurement. For example, the active hydrogen equivalent of the hardener used can be determined by reacting a monoepoxy resin having a known epoxy equivalent such as phenyl glycidyl ether with a hardener having an unknown active hydrogen equivalent, and measuring the amount of the monoepoxy resin consumed.

Examples of the phenol resin-based curing agent that can be used in combination include: bisphenols such as bisphenol A, bisphenol F, bisphenol C, bisphenol K, bisphenol Z, bisphenol S, tetramethylbisphenol A, tetramethylbisphenol F, tetramethylbisphenol S, tetramethylbisphenol Z, dihydroxybiphenyl sulfide, bisphenol TMC, 4 '- (9-fluorenylidene) diphenol, and 4, 4' -thiobis (3-methyl-6-tert-butylphenol), dihydroxybenzenes such as catechol, resorcinol, methylresorcinol, hydroquinone, monomethylhydroquinone, dimethylhydroquinone, trimethylhydroquinone, mono-tert-butylhydroquinone, and di-tert-butylhydroquinone, hydroxynaphthalenes such as dihydroxynaphthalene, dihydroxymethylnaphthalene, and trihydroxynaphthalene, phosphorus-containing phenol hardeners such as LC-950PM60 (manufactured by Shin-AT & C), and SHONEX BRG-555 (manufactured by Aica Kogyo Co., Ltd.) (phenol produced by Shonol) BRG-555) Phenol, naphthol, biphenol and/or bisphenol condensate with aldehyde, such as phenol, naphthol, biphenol and/or bisphenol, condensate of phenol, naphthol, biphenol and/or bisphenol and xylylene glycol, such as phenol, naphthol, biphenol and/or bisphenol, and isopropenylacetophenone, and condensate of phenol, naphthol, biphenol and/or bisphenol and biphenyl condensing agent, such as phenol, naphthol, and/or bisphenol, are so-called "novolak varnish", such as cresol novolak resin, cresol novolak resin such as DC-5 (manufactured by Nippon iron chemical & materials Co., Ltd.), aromatic modified phenol novolak resin, bisphenol A novolak resin, and lengilgto (Resitop) TPM-100 (manufactured by Jur chemical industries Co., Ltd.), condensate of phenol, naphthol, and/or bisphenol and xylylene, condensate of phenol, naphthol, biphenol and/or bisphenol and biphenyl condensing agent Phenol compounds of phenol resin "and triazine ring and hydroxyphenyl group-containing compounds such as PS-6313 (manufactured by Roche chemical industries, Ltd.). From the viewpoint of easy availability, preferred are phenol novolac resins, trishydroxyphenylmethane-type novolac resins, aromatic-modified phenol novolac resins, and the like.

In the case of the novolak-type phenol resin, examples of the phenol include phenol, cresol, xylenol, butylphenol, pentylphenol, nonylphenol, butylmethylphenol, trimethylphenol, phenylphenol and the like, examples of the naphthol include 1-naphthol, 2-naphthol and the like, and further examples of the biphenol and the bisphenol described above.

Examples of the aldehydes include: formaldehyde, acetaldehyde, propionaldehyde, butyraldehyde, valeraldehyde, caproaldehyde, benzaldehyde, chloral, bromoaldehyde, glyoxal, malonaldehyde, succinaldehyde, glutaraldehyde, adipaldehyde, heptaldehyde, sebacaldehyde, acrolein, crotonaldehyde, salicylaldehyde, phthalaldehyde, hydroxybenzaldehyde, and the like.

Examples of the biphenyl-based condensing agent include bis (hydroxymethyl) biphenyl, bis (methoxymethyl) biphenyl, bis (ethoxymethyl) biphenyl, and bis (chloromethyl) biphenyl.

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

Specific examples of the amine-based curing agent include: and amine compounds such as diethylenetriamine, triethylenetetramine, m-xylylenediamine, isophoronediamine, diaminodiphenylmethane, diaminodiphenylsulfone, diaminodiphenylether, benzyldimethylamine, 2, 4, 6-tris (dimethylaminomethyl) phenol, dicyanodiamide, and polyamidoamine which is a condensate of an acid such as a dimer acid and a polyamine.

Specific examples of the other curing agents include: phosphine compounds such as triphenylphosphine, phosphonium salts such as tetraphenylphosphonium bromide, imidazoles such as 2-methylimidazole, 2-phenylimidazole, 2-ethyl-4-methylimidazole, 2-undecylimidazole and 1-cyanoethyl-2-methylimidazole, imidazole salts as salts of imidazoles with trimellitic acid, isocyanuric acid or boric acid, amines such as benzyldimethylamine and 2, 4, 6-tris (dimethylaminomethyl) phenol, quaternary ammonium salts such as trimethylammonium chloride, diazabicyclo compounds, salts of diazabicyclo compounds with phenols or phenol novolak resins, complex compounds of boron trifluoride with amines or ether compounds, aromatic phosphonium salts or aromatic iodonium salts, hydrazides or acidic polyesters.

In addition, in order to adjust the hardenability, the epoxy resin composition of the present invention may use a conventional reaction retarder. For example, boric acid ester, phosphoric acid, alkyl phosphate, p-toluenesulfonic acid, and the like can be used.

Examples of the boric acid ester include: tributyl borate, trimethoxyboroxine (trimethoxyboroxine), ethyl borate, epoxy-phenol-borate formulations (e.g., kukukukukukukusho (curreid) L-07N (manufactured by national chemical industry ltd.), etc., and examples of the alkyl phosphate ester include trimethyl phosphate, tributyl phosphate, etc.

The reaction retarder may be used alone or in combination of two or more, and is preferably used alone in terms of ease of adjustment of the amount used, and particularly, it is most effective when a small amount of boric acid is used. When used, the composition can be dissolved in an alcohol solvent such as methanol, butanol, or 2-propanol, and used at a concentration of 5 to 20% by mass. Particularly, when the curing agent is dicyanodiamine, boric acid is preferably 0.1 to 0.5 mol based on 1mol of the curing agent, and more preferably 0.15 to 0.35 mol in terms of obtaining a retardation effect and heat resistance. When the curing agent is a phenol curing agent, the amount is preferably 0.1 to 5 parts by mass, and more preferably 0.1 to 1 part by mass, in terms of obtaining heat resistance, based on the phosphorus-containing epoxy resin. Particularly, if the amount of boric acid used is increased to 5 parts by mass or more, the amount of a reaction accelerator such as imidazole is required to be increased in order to adjust the hardening properties, and the insulation reliability of the hardened product is remarkably impaired, which is not preferable.

The epoxy resin composition may optionally use a hardening accelerator. Examples thereof include: imidazoles such as 2-methylimidazole, 2-ethylimidazole and 2-ethyl-4-methylimidazole, tertiary amines such as 2- (dimethylaminomethyl) phenol and 1, 8-diaza-bicyclo (5, 4, 0) undecene-7, phosphines such as triphenylphosphine, tricyclohexylphosphine and triphenylphosphine triphenylborane, and metal compounds such as tin octylate. The curing accelerator may be used in an amount of 0.02 to 5.0 parts by mass, as required, based on 100 parts by mass of the epoxy resin in the epoxy resin composition. By using the hardening accelerator, the hardening temperature can be lowered or the hardening time can be shortened.

The epoxy resin composition may also use an organic solvent or a reactive diluent for adjusting the viscosity.

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

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 cresyl glycidyl ether, or difunctional glycidyl ethers such as resorcinol diglycidyl ether, neopentyl glycol diglycidyl ether, 1, 4-butanediol diglycidyl ether, 1, 6-hexanediol diglycidyl ether, cyclohexanedimethanol diglycidyl ether, and propylene glycol diglycidyl ether, or polyfunctional glycidyl ethers such as glycerol polyglycidyl ether, trimethylolpropane polyglycidyl ether, trimethylolethane polyglycidyl ether, pentaerythritol polyglycidyl ether and the like, or glycidyl esters such as glycidyl neodecanoate, or glycidyl amines such as phenyl diglycidyl amine and tolyl diglycidyl amine, but the present invention is not limited thereto.

These organic solvents and reactive diluents are preferably used alone or in a mixture of two or more thereof in an amount of 90% by mass or less of nonvolatile components, and the appropriate type and amount of use may be selected as appropriate depending on the application. For example, in the case of use in a printed wiring board, a polar solvent having a boiling point of 160 ℃ or lower such as methyl ethyl ketone, acetone, or 1-methoxy-2-propanol is preferable, and the amount used is preferably 40 to 80% by mass in terms of nonvolatile components. In the application of the adhesive film, for example, ketones, acetates, carbitols, aromatic hydrocarbons, dimethylformamide, dimethylacetamide, N-methylpyrrolidone, and the like are preferably used, and the amount thereof is preferably 30 to 60% by mass in terms of nonvolatile components.

An inorganic filler may be used as the epoxy resin composition as required. Specific examples thereof include: fused silica, crystalline silica, alumina, silicon nitride, aluminum hydroxide, magnesium hydroxide, talc, calcined talc, mica, clay, kaolin, boehmite, calcium carbonate, calcium silicate, calcium hydroxide, magnesium carbonate, barium sulfate, titanium oxide, boron nitride, carbon, glass powder, silica balloon (silica balloon) and other inorganic fillers, and pigments and the like may also be blended. The inorganic filler is generally used for the purpose of improving impact resistance, but contributes to dimensional stability as a measure against warpage of the substrate due to thermal expansion. Further, metal hydroxides such as aluminum hydroxide, boehmite, and magnesium hydroxide may be used for the purpose of supplementing tracking resistance in addition to functioning as a flame retardant aid. When the phosphorus content of the composition is reduced, although it is effective in securing flame retardancy, the use of a large amount thereof greatly reduces the moldability of the substrate. Particularly, when the blending amount is not 10% by mass or more, the impact resistance effect is small, whereas when the blending amount exceeds 150% by mass, there is a possibility that the adhesiveness required for the use as a laminate is lowered or other molding characteristics such as drilling workability are lowered. Further, if necessary, a fibrous filler such as glass fiber, carbon fiber, alumina fiber, silica alumina fiber, silicon carbide fiber, polyester fiber, cellulose fiber, and aramid fiber, or an organic filler such as particulate rubber or thermoplastic elastomer may be used in combination to such an extent that the characteristics of the present invention are not impaired.

The epoxy resin composition may contain other thermosetting resins and thermoplastic resins within a range not impairing the properties. Examples thereof include: phenol 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 resin, polyethersulfone resin, polysulfone resin, polyetheretherketone resin, polyphenylene sulfide resin, polyvinyl formal (polyvinyl formal) resin, and the like, but is not limited thereto.

In addition, in order to improve the cured product flame resistance, the epoxy resin composition can also be used with the existing various flame retardant. Examples of the flame retardant usable in combination include a phosphorus flame retardant, a nitrogen flame retardant, a silicone flame retardant, an inorganic flame retardant, and an organic metal salt flame retardant, and a phosphorus flame retardant is particularly preferable. These flame retardants may be used alone or in combination of two or more.

The phosphorus flame retardant may be an inorganic phosphorus compound or an organic phosphorus compound. Examples of the inorganic phosphorus-containing compound include red phosphorus, monoammonium phosphates, diammonium phosphates, triammonium phosphates, ammonium polyphosphates and other inorganic nitrogen-containing phosphorus compounds such as phosphoric acid amides. Examples of the organic phosphorus-based compound include aliphatic phosphate esters, phosphate ester compounds, general-purpose organic phosphorus-based compounds such as condensed phosphate esters such as PX-200 (manufactured by Dai eight chemical industries, Ltd.), phosphonic acid compounds, phosphinic acid compounds, phosphine oxide compounds, phosphorane compounds, phosphazene compounds and other organic nitrogen-containing phosphorus compounds, metal salts of phosphinic acid, and in addition, cyclic organic phosphorus compounds such as DOPO, DOPO-HQ and DOPO-NQ, and phosphorus-containing epoxy resins and phosphorus-containing hardeners which are derivatives obtained by reacting these compounds with epoxy resins or phenol resins. When a phosphorus flame retardant is used, a flame retardant aid such as magnesium hydroxide may be used in combination.

The epoxy resin composition of the present invention is cured to obtain a cured product. In the case of curing, for example, a resin sheet, a copper foil with resin, a prepreg, or the like is formed, and the laminate is obtained by laminating and curing under heat and pressure.

When the epoxy resin composition is formed into a plate-like substrate or the like, a fibrous filler is preferable in terms of dimensional stability, flexural strength, and the like. More preferably, a glass fiber substrate formed by weaving glass fibers into a mesh is used.

The epoxy resin composition may further contain various additives such as a silane coupling agent, an antioxidant, a mold release agent, an antifoaming agent, an emulsifier, a thixotropy imparting agent, and a smoothing agent, as required. These additives are preferably contained in an amount of 0.01 to 20% by mass based on the epoxy resin composition.

The epoxy resin composition can be impregnated into a fibrous base material to prepare a prepreg used for a printed wiring board or the like. As the fibrous base material, a woven or nonwoven fabric of inorganic fibers such as glass, or organic fibers such as polyester resin, polyamine resin, polyacrylic resin, polyimide resin, and aromatic polyamide resin can be used, but the fibrous base material is not limited thereto. The method for producing a prepreg from an epoxy resin composition is not particularly limited, and for example, the prepreg can be obtained by impregnating an epoxy resin composition in a resin varnish prepared by adjusting the viscosity with a solvent, and then half-curing (B-staging) the resin component by heat drying, and can be heat-dried at 100to 200 ℃ for 1 to 40 minutes, for example. Here, the amount of the resin in the prepreg is preferably 30 to 80 mass% based on the resin component.

In order to cure the prepreg, a curing method of a laminate board generally used in the production of a printed wiring board may be used, but the curing method is not limited thereto. For example, when a laminated plate is formed using a prepreg, a laminate is formed by laminating one or more prepregs, disposing metal foils on one side or both sides, and the laminate is heated and pressed to be integrally laminated. Here, as the metal foil, copper, aluminum, brass, nickel, or the like can be used alone, and an alloy or composite metal foil can be used. Further, the prepreg can be hardened by subjecting the resulting laminate to pressure heating to obtain a laminate. In this case, it is preferable that the heating temperature is 160 to 220 ℃ and the pressurizing pressure is 50N/cm²～500N/cm²The target cured product can be obtained by setting the heating and pressing time to 40 to 240 minutes. If the heating temperature is low, the curing reaction may not proceed sufficiently, and if the heating temperature is high, the epoxy resin composition may start to decompose. If the pressing pressure is low, air bubbles may remain in the interior of the resulting laminated sheet, and the electrical characteristics may be degraded, while if the pressing pressure is high, the resin may flow before curing, and a cured product having a desired thickness may not be obtained. Further, if the heating and pressing time is short, the curing reaction may not be sufficiently performed, and if the heating and pressing time is long, the epoxy resin composition in the prepreg may be thermally decomposed, which is not preferable.

The epoxy resin composition can be cured by the same method as that for conventional epoxy resin compositions to obtain a cured epoxy resin. As a method for obtaining a cured product, a method similar to a conventional epoxy resin composition can be used, and a method of forming a laminate by laminating a resin sheet, a resin-coated copper foil, a prepreg or the like, and heating and pressure curing can be suitably used, for example, injection molding, potting (potting), dipping, drop coating (drip coating), transfer molding, compression molding or the like. The curing temperature in this case is usually in the range of 100to 300 ℃ and the curing time is usually about 1 to 5 hours.

As a result of preparing an epoxy resin composition using a phosphorus-containing epoxy resin and evaluating a laminate obtained by heat curing, an epoxy resin composition which is obtained by reacting a specific phosphorus compound with a novolak-type epoxy resin having a specific molecular weight distribution and a specific average number of functional groups and which exhibits high heat resistance and flame retardancy as compared with conventional phosphorus-containing epoxy resins, and which can improve dielectric characteristics and physical properties of a cured product can be provided.

[ examples ]

The present invention will be specifically described below with reference to examples and comparative examples, but the present invention is not limited to these examples. Unless otherwise specified, "part" represents part by mass and "%" represents mass%. The measurement methods were each performed by the following method. The units of the equivalent are all "g/eq.

Epoxy equivalent: the measurement was carried out in accordance with Japanese Industrial Standards (JIS) K7236. Specifically, an automatic potentiometric titration apparatus (COM-1600 ST, manufactured by Pontana industries, Ltd.) was used, and a tetraethylammonium bromide acetic acid solution was added using chloroform as a solvent, and titration was performed using a 0.1mol/L perchloric acid-acetic acid solution.

Phosphorus content: to a sample (150 mg), 3mL of sulfuric acid was added and the mixture was heated for 30 minutes. The reaction mixture was returned to room temperature, and 3.5mL of nitric acid and 0.5mL of perchloric acid were added to the mixture, followed by decomposition under heating until the contents became transparent or yellow. The liquid was diluted with water in a 100mL measuring flask. The sample solution (10 mL) was put in a 50mL volumetric flask, 1 drop of phenolphthalein indicator was added, 2mol/L ammonia water was added until the color became reddish, and then 2mL of 50% sulfuric acid solution was added, and water was added. After adding 5mL of an aqueous solution of ammonium metavanadate (2.5 g/L) and 5mL of an aqueous solution of ammonium molybdate (50 g/L), the volume was fixed with water. After standing at room temperature for 40 minutes, the measurement was carried out using a spectrophotometer at a wavelength of 440nm with water as a control. A calibration curve was prepared in advance using an aqueous potassium dihydrogen phosphate solution, and the phosphorus content was determined from the absorbance.

Glass transition temperature (Tg): the temperature of DSC-Tgm (the temperature in the middle of the variation curve relative to the tangent between the glass state and the rubber state) when the measurement is performed under a temperature rise condition of 20 ℃ per minute using a Differential Scanning Calorimeter (Difference Scanning Calorimeter, DSC)6200 manufactured by Hitachi High-Tech Science Co., Ltd., Aicolor tower (EXSTAR) 6000.

Pressure Cooker Test (PCT) solder heat resistance, water resistance: the test piece prepared according to JIS C6481 was treated in an autoclave at 121 ℃ and 0.2MPa for 3 hours, and then immersed in a solder bath at 260 ℃. The case where swelling or peeling did not occur for 20 minutes or more was evaluated as omicron, the case where swelling or peeling occurred within 10 minutes was evaluated as x, and the other cases were evaluated as Δ.

Thermal peel test (thermal mechanical analysis, TMA) method) T-288: the test was carried out at 288 ℃ according to International Association Connecting Electronics Industries (IPC) TM-650 TM2.4.24.1.

Copper foil peel strength: measured according to JIS C6481, 5.7.

Combustibility: according to UL94 (Underwriters Laboratories Inc.). The test was conducted on 5 test pieces, and based on the total time of the duration of the flaming combustion after the first and second flame contact (10 times for 2 times for each of the 5 test pieces), the test pieces were judged by V-0, V-1 and V-2 which were criteria for the same specification. Further, the case of complete burn-out is determined to be NG.

Relative dielectric constant and dielectric loss tangent: the value at a frequency of 2GHz after being stored in a room at 23 ℃ and a humidity of 50% for 24 hours after being completely dried was measured by using a cavity resonance method (vector network analyzer (VNA) E8363B (manufactured by Agilent Technology) and a cavity resonator perturbation method dielectric constant measuring apparatus (manufactured by kanto electronic application development)).

Three nuclei, seven nuclei or more, number average molecular weight (Mn): determined by GPC measurement. Specifically, a column (TSKgelG 4000H, manufactured by Tosoh corporation, manufactured by HLC-8220GPC) was included in series in a body (HLC-8220 GPC, manufactured by Tosoh corporation, manufactured by HLC-8220GPC)_XL、TSKgelG3000H_XL、TSKgelG2000H_XL) The column temperature was set to 40 ℃. Further, THF was used as an eluent, and an RI (differential refractometer) detector was used as a detector, with a flow rate of 1 mL/min. The measurement sample was obtained by dissolving 0.05g of the sample in 10mL of THF in 50. mu.L of the solution and filtering the solution through a microfilter. The data was processed using GPC-8020 model II version 6.00, manufactured by Tosoh corporation. The Mn was converted from a calibration curve obtained from standard monodisperse polystyrenes (A-500, A-1000, A-2500, A-5000, F-1, F-2, F-4, F-10, F-20, and F-40, manufactured by Tosoh corporation) based on the area% of the peak value for three or more nuclei and seven or more nuclei.

Synthesis example 1

In a four-necked separable flask made of glass including a stirrer, a temperature adjusting device, a reflux condenser, a total condenser, a pressure reducing device and the like, 1000 parts of phenol was charged and heated to 80 ℃, 2.8 parts of oxalic acid dihydrate was added thereto and dissolved by stirring, and 142 parts of 37.5% formalin was added dropwise over 30 minutes. Thereafter, the reaction temperature was maintained at 92 ℃ and the reaction was carried out for 3 hours. After the reaction, the temperature was raised to 110 ℃ to dehydrate the phenol, and the residual phenol was recovered under the recovery conditions of 150 ℃ and 60mmHg at about 90%, and then recovered under the recovery conditions of 5mmHg, and further 10 parts of water was added dropwise under the conditions of 160 ℃ and 80mmHg for 90 minutes to remove the residual phenol, and then nitrogen was bubbled through the molten phenol novolak resin for 60 minutes, to obtain a phenol novolak resin (N0).

With respect to the obtained N0, a part of the dinuclear bodies was further distilled off using a thin film distiller of 5mmHg at 280 ℃ to obtain a phenol novolac resin (N1). The obtained N1 was as follows: the softening point was 65 ℃, 10.8 area% for the two core bodies, 52.9 area% for the three core bodies, 21.8 area% for the four core bodies, 8.5 area% for the five core bodies, and 6.0 area% for the six core bodies, with an actual average molecular weight of 355.

Synthesis example 2

N0 obtained in synthesis example 1 was used, and a part of the dinuclear bodies was distilled off more strongly using a thin film distiller of 5mmHg at 300 ℃ to obtain a phenol novolac resin (N2). The obtained N2 was as follows: the softening point was 66 ℃, 5.9 area% for the binuclear, 58.4 area% for the trinuclear, 22.9 area% for the tetrakaryon, 8.3 area% for the pentakaryon, 4.6 area% for the hexakaryon, and the actual average molecular weight was 356.

Synthesis example 3

Into a four-necked separable flask made of glass equipped with a stirrer, a temperature adjusting device, a reflux condenser, a total condenser, a nitrogen gas introducing device, a pressure reducing device and a dropping device, 1000 parts of N1 and 0.38 part of oxalic acid dihydrate obtained in synthesis example 1 were charged, and the mixture was stirred while introducing nitrogen gas and heated to raise the temperature. 13.5 parts of 37.5% formalin was added dropwise at 80 ℃ and the addition was terminated in 30 minutes. Thereafter, the reaction was carried out for 3 hours while keeping the reaction temperature at 92 ℃ and then raising the temperature to 110 ℃ to remove the reaction product water from the system. Finally, heating was carried out at 160 ℃ for 2 hours to obtain a phenol novolac resin (N3). The obtained N3 was as follows: the softening point was 63 ℃, the area of the binuclear bodies was 9.4%, the area of the trinuclear bodies was 48.1%, the area of the heptanuclear bodies was 9.0%, and the Mn was 552. The GPC measurement chart of N3 is shown in fig. 1. Fig. 2 shows a GPC measurement chart of a general-purpose phenol novolac type epoxy resin. The horizontal axis represents dissolution time (minutes) and the vertical axis represents detection intensity (mV). The peak represented by A is a trinuclear body, and the peak represented by B is a heptakaryon or more.

Subsequently, 500 parts of N3, 2200 parts of epichlorohydrin and 400 parts of diethylene glycol dimethyl ether were charged into the same apparatus, dissolved at 60 ℃ and then, 332 parts of 49% aqueous solution of caustic soda was added dropwise over 2 hours while maintaining the temperature at 58 to 62 ℃ under a reduced pressure of 130 mmHg. During this time, epichlorohydrin was azeotroped with water, and distilled water was successively removed to the outside of the system. Thereafter, the reaction was continued under the same conditions for 2 hours. After completion of the reaction, epichlorohydrin was recovered at 150 ℃ under 5mmHg, and 1200 parts of methyl isobutyl ketone (MIBK) was added to dissolve the product. Thereafter, 70 parts of a 10% aqueous sodium hydroxide solution was added thereto, and the mixture was reacted at 80 to 90 ℃ for 2 hours, 1000 parts of water was added to dissolve the by-produced common salt, and the mixture was allowed to stand to separate and remove the lower layer of common salt solution. And neutralizing with phosphoric acid water solution, washing the resin solution with water until the water washing solution becomes neutral, refluxing and dehydrating, and filtering to remove impurities. Then, the mixture was heated to 150 ℃ under reduced pressure of 5mmHg, and MIBK was distilled off to obtain a phenol novolak-type epoxy resin (E1). The obtained E1 was as follows: the epoxy equivalent was 171, Mn was 650, the area% of the trinuclears was 40.6, the area% of the heptakaryons was 20.9 or more, the ratio (L/H) of the content (area% L) of the trinuclears to the content (area% H) of the heptakaryons was 1.9, and the average number of functional groups (Mn/E) was 3.8.

Synthesis example 4

A phenol novolac resin (N4) was obtained in the same manner as in synthesis example 3, except that 1000 parts of N1, 0.63 parts of oxalic acid dihydrate, and 22.5 parts of 37.5% formalin were charged. The obtained N4 was as follows: the softening point was 69 ℃, the area of the binuclear bodies was 8.0%, the area of the trinuclear bodies was 43.7%, the area of the heptanuclear bodies was 14.2% or more, and the Mn was 574. Thereafter, epoxidation of N4 was carried out in the same manner as in synthesis example 3 to obtain a phenol novolac-type epoxy resin (E2). The obtained E2 was as follows: the epoxy equivalent was 172, Mn was 682, three nuclei were 36.4 area%, seven nuclei and 26.7 area%, the content ratio (L/H) was 1.4, and the average number of functional groups (Mn/E) was 4.0.

Synthesis example 5

A phenol novolac resin (N5) was obtained in the same manner as in synthesis example 3, except that 1000 parts of N1, 1.89 parts of oxalic acid dihydrate, and 67.6 parts of 37.5% formalin were charged. The obtained N5 was as follows: the softening point was 78 ℃, 7.2 area% for the binuclear bodies, 31.2 area% for the trinuclear bodies, 30.9 area% for the heptanuclear bodies or more, and 690 for Mn. Thereafter, epoxidation of N5 was carried out in the same manner as in synthesis example 3 to obtain a phenol novolac-type epoxy resin (E3). The obtained E3 was as follows: the epoxy equivalent was 173, Mn was 824, the area of the triads was 26.1%, the area of the heptanes or higher was 42.2%, the content ratio (L/H) was 0.6, and the average number of functional groups (Mn/E) was 4.8.

Synthesis example 6

A phenol novolac resin (N6) was obtained in the same manner as in synthesis example 3, except that 1000 parts of N2, 0.63 parts of oxalic acid dihydrate, and 22.5 parts of 37.5% formalin were charged. The obtained N6 was as follows: the softening point was 70 ℃, the area of the secondary nuclei was 5.1%, the area of the tertiary nuclei was 45.8%, the area of the heptanuclear or higher was 14.4%, and the Mn was 589. Thereafter, epoxidation of N6 was carried out in the same manner as in synthesis example 3 to obtain a phenol novolac-type epoxy resin (E4). The obtained E4 was as follows: the epoxy equivalent was 174, Mn was 693, the number of the three nuclei was 38.8 area%, the number of the seven nuclei or more was 26.0 area%, the content ratio (L/H) was 1.5, and the average number of functional groups (Mn/E) was 4.0.

Synthesis example 7

A phenol novolac resin (N7) was obtained in the same manner as in synthesis example 3, except that 1000 parts of LV-70S (phenol novolac resin manufactured by gordon chemical industry, softening point 65 ℃, 1.0 area% for binuclears, 74.7 area% for trinuclears, 18.1 area% for tetrakaryons, 6.2 area% for pentakaryons, measured number average molecular weight 337), 0.66 parts of oxalic acid dihydrate, and 23.7 parts of 37.5% formalin were charged. The obtained N7 was as follows: the softening point was 67 ℃, the area of the secondary nuclei was 1.1%, the area of the tertiary nuclei was 57.3%, the separation of the six nuclei from the seven nuclei was difficult, the content of six or more nuclei was 22.0%, and the Mn was 580%. Thereafter, epoxidation of N7 was carried out in the same manner as in synthesis example 3 to obtain a phenol novolac-type epoxy resin (E5). The obtained E5 was as follows: the epoxy equivalent was 173, Mn was 669, the area of the triad was 48.9%, the area of the heptanucleus or more was 14.6%, the content ratio (L/H) was 3.3, and the average number of functional groups (Mn/E) was 3.9.

Synthesis example 8

A phenol novolac resin (N8) was obtained in the same manner as in synthesis example 3, except that 1000 parts of N1, 0.32 part of oxalic acid dihydrate, and 11.3 parts of 37.5% formalin were charged. The obtained N8 was as follows: the softening point was 62 ℃, the area of the secondary nuclei was 9.6%, the area of the tertiary nuclei was 48.4%, the area of the heptanuclear or higher was 7.7%, and the Mn was 545. Thereafter, epoxidation of N8 was carried out in the same manner as in synthesis example 3 to obtain a phenol novolac-type epoxy resin (E6). The obtained E6 was as follows: the epoxy equivalent was 171, Mn was 623, the area% of the three nuclei was 41.9, the area% of the seven or more nuclei was 19.9, the content ratio (L/H) was 2.1, and the average number of functional groups (Mn/E) was 3.6.

Synthesis example 9

A phenol novolac resin (N9) was obtained in the same manner as in synthesis example 3, except that 1000 parts of N1, 2.52 parts of oxalic acid dihydrate, and 90.1 parts of 37.4% formalin were charged. The obtained N9 was as follows: the softening point is 84 ℃, the area of the two nuclei is 5.7 percent, the area of the three nuclei is 24.1 percent, the area of the seven nuclei is more than 41.5 percent, and the Mn is 748. Thereafter, epoxidation of N9 was carried out in the same manner as in synthesis example 3 to obtain a phenol novolac-type epoxy resin (E7). The obtained E7 was as follows: the epoxy equivalent was 175, Mn was 858, 20.7 area% for three nuclei, 48.5 area% for seven or more nuclei, the content ratio (L/H) was 0.4, and the average number of functional groups (Mn/E) was 4.9.

Synthesis example 10

YDPN-638 (phenol novolac type epoxy resin, having an epoxy equivalent of 178, manufactured by hitachi chemical & materials gmbh) and YDF-170 (bisphenol F type liquid epoxy resin, having an epoxy equivalent of 168, manufactured by hitachi chemical & materials gmbh) were melt-mixed at a mass ratio of 1/1 to obtain phenol novolac type epoxy resin (E8). The obtained E8 was as follows: the epoxy equivalent was 173, Mn was 468, 12.1 area% for the three nuclei, 19.3 area% for the seven or more nuclei, the content ratio (L/H) was 0.6, and the average number of functional groups (Mn/E) was 2.7.

Synthesis example 11

In a four-necked separable flask made of glass equipped with a stirrer, a temperature adjusting device, a reflux condenser, a total condenser and a nitrogen introducing device, 100 parts of HCA (DOPO, manufactured by Sanko Co., Ltd.) and 185 parts of toluene were charged, and the mixture was dissolved by heating at 80 ℃. Thereafter, 62.2 parts of 1, 4-Naphthoquinone (NQ) was separately added while paying attention to the temperature rise due to the reaction heat. At this time, the molar ratio of NQ to DOPO (NQ/DOPO) was 0.85. After the reaction, 627 parts of epoxy resin E1 was added, and the mixture was stirred while introducing nitrogen gas, and heated until 130 ℃ was reached to be dissolved. 0.08 part of Triphenylphosphine (TPP) was added thereto, and after a reaction at 150 ℃ for 4 hours, 42 parts of methoxypropanol was added thereto, followed by a further reaction at 140 ℃ for 2 hours, to obtain a phosphorus-containing epoxy resin (PE 1). The PE1 obtained was as follows: the epoxy equivalent was 263 and the phosphorus content was 1.8%. The reaction rate (consumption rate of the raw material phosphorus compound calculated from the measured epoxy equivalent) was 78%.

Synthesis example 12

A phosphorus-containing epoxy resin (PE2) was obtained in the same manner as in synthesis example 11, except that 627 parts of E2 was used as the epoxy resin. The PE2 obtained was as follows: the epoxy equivalent was 261 and the phosphorus content was 1.8%. The reaction rate was 72%.

Synthesis example 13

A phosphorus-containing epoxy resin (PE3) was obtained in the same manner as in synthesis example 11, except that 627 parts of E3 was used as the epoxy resin. The PE3 obtained was as follows: the epoxy equivalent was 261 and the phosphorus content was 1.8%. The reaction rate was 70%.

Synthesis example 14

A phosphorus-containing epoxy resin (PE4) was obtained in the same manner as in synthesis example 11, except that 627 parts of E4 was used as the epoxy resin. The PE4 obtained was as follows: the epoxy equivalent was 264 and the phosphorus content was 1.8%. The reaction rate was 72%.

Synthesis example 15

A phosphorus-containing epoxy resin (PE5) was obtained in the same manner as in synthesis example 11, except that 627 parts of E5 was used as the epoxy resin. The PE5 obtained was as follows: the epoxy equivalent was 262, and the phosphorus content was 1.8%. The reaction rate was 72%.

Synthesis example 16

A phosphorus-containing epoxy resin (PE6) was obtained in the same manner as in synthesis example 11, except that 72.4 parts of NQ (NQ/DOPO is 0.99) and 0.09 parts of TPP were used, and 715 parts of E5 were used as the epoxy resin. The PE6 obtained was as follows: the epoxy equivalent was 276 and the phosphorus content was 1.6%. The reaction rate was 100%.

Synthesis example 17

A phosphorus-containing epoxy resin (PE7) was obtained in the same manner as in synthetic example 11, except that 36.6 parts of NQ (NQ/DOPO is 0.50) and 0.07 part of TPP were used, and 431 parts of E2 were used as the epoxy resin. The PE7 obtained was as follows: the epoxy equivalent was 313, and the phosphorus content was 2.5%. The reaction rate was 100%.

Synthesis example 18

A phosphorus-containing epoxy resin (PE8) was obtained in the same manner as in synthesis example 11, except that the amount of NQ was 68.0 parts (NQ/DOPO was 0.93) and the amount of epoxy resin was 542 parts of E2. The PE8 obtained was as follows: the epoxy equivalent was 278 and the phosphorus content was 2.0%. The reaction rate was 67%.

Synthesis example 19

A phosphorus-containing epoxy resin (PEH1) was obtained in the same manner as in synthesis example 11, except that 627 parts of E6 was used as the epoxy resin. The PEH1 obtained was as follows: the epoxy equivalent was 263 and the phosphorus content was 1.8%. The reaction rate was 78%.

Synthesis example 20

A phosphorus-containing epoxy resin (PEH2) was obtained in the same manner as in synthesis example 11, except that 627 parts of E7 was used as the epoxy resin. The PEH2 obtained was as follows: the epoxy equivalent was 264 and the phosphorus content was 1.8%. The reaction rate was 69%.

Synthesis example 21

A phosphorus-containing epoxy resin (PEH3) was obtained in the same manner as in synthesis example 11, except that 627 parts of a phenol novolac-type epoxy resin was used as the epoxy resin (YDPN-6300, available from hitachi chemical & materials co., ltd., YDPN-6300, an epoxy amount of 175, an Mn of 653, 35.2 area% of three core bodies, 21.8 area% or more of seven core bodies, a content ratio (L/H) of 1.6, and an average number of functional groups (Mn/E) of 3.7). The PEH3 obtained was as follows: the epoxy equivalent was 266% and the phosphorus content was 1.8%. The reaction rate was 72%.

Synthesis example 22

A phosphorus-containing epoxy resin (PEH4) was obtained in the same manner as in synthesis example 11, except that 627 parts of a phenol novolac-type epoxy resin was used as the epoxy resin (YDPN-638, available from hitachi chemical & materials co., ltd., single epoxy amount 178, Mn 662, 14.7 area% of three core bodies, 38.6 area% or more of seven core bodies, content ratio (L/H) of 0.4, and average number of functional groups (Mn/E) of 3.7). The PEH4 obtained was as follows: the epoxy equivalent was 272 and the phosphorus content was 1.8%. The reaction rate was 72%.

Synthesis example 23

A phosphorus-containing epoxy resin (PEH5) was obtained in the same manner as in synthesis example 11, except that 627 parts of a phenol novolac-type epoxy resin was used as the epoxy resin (N775, the epoxy content was 187, the Mn was 1308, the tricarbone was 6.7 area%, the heptanuclear was 71.6 area% or more, the content ratio (L/H) was 0.1, and the average number of functional groups (Mn/E) was 7.0). The PEH5 obtained was as follows: the epoxy equivalent was 278 and the phosphorus content was 1.8%. The reaction rate was 60%.

Synthesis example 24

A phosphorus-containing epoxy resin (PEH6) was obtained in the same manner as in synthetic example 11, except that the epoxy resin was E8 in which NQ was 68.0 parts (NQ/DOPO was 0.93) and TPP was 0.17 parts and the epoxy resin was 542 parts. The PEH6 obtained was as follows: the epoxy equivalent was 317 and the phosphorus content was 2.0%. The reaction rate was 100%.

The following are short names of epoxy resin, oxazine resin, phenol resin, and other materials used.

[ epoxy resin ]

PE 1: synthesis of phosphorus-containing epoxy resin obtained in example 11

PE 2: synthesis of phosphorus-containing epoxy resin obtained in Synthesis example 12

PE 3: synthesis of phosphorus-containing epoxy resin obtained in Synthesis example 13

PE 4: synthesis of phosphorus-containing epoxy resin obtained in Synthesis example 14

PE 5: synthesis of phosphorus-containing epoxy resin obtained in Synthesis example 15

PE 6: synthesis of phosphorus-containing epoxy resin obtained in Synthesis example 16

PE 7: synthesis of phosphorus-containing epoxy resin obtained in Synthesis example 17

PE 8: synthesis of phosphorus-containing epoxy resin obtained in EXAMPLE 18

PEH 1: synthesis of phosphorus-containing epoxy resin obtained in example 19

PEH 2: synthesis of phosphorus-containing epoxy resin obtained in example 20

PEH 3: synthesis of phosphorus-containing epoxy resin obtained in Synthesis example 21

PEH 4: synthesis of phosphorus-containing epoxy resin obtained in Synthesis example 22

PEH 5: synthesis of phosphorus-containing epoxy resin obtained in Synthesis example 23

PEH 6: synthesis of phosphorus-containing epoxy resin obtained in Synthesis example 24

E9: dicyclopentadiene type epoxy resin (HP-7200H, epoxy equivalent 273 manufactured by Diegon (DIC) Co., Ltd.)

E10: naphthol aralkyl type epoxy resin (NC-3000H, 292 epoxy equivalent, manufactured by Nippon chemical Co., Ltd.)

[ phenol resin ]

H1: dicyclopentadiene type phenol resin (GDP-6140, active hydrogen equivalent: 196, manufactured by Rongche chemical industries, Ltd.)

H2: 4, 4- (1, 3-adamantanediyl) diphenol resin (active hydrogen equivalent of 191)

H3: phenol novolac type resin (Resitop PSM-6358, softening point 118 ℃ C., active hydrogen equivalent 106, manufactured by Dogrong chemical industries, Ltd.)

[ oxazine resin ]

B1: phenolphthalein type benzoxazine resin (active hydrogen equivalent of 276)

B2: phenol red benzoxazine resin (active hydrogen equivalent of 294)

B3: phenolphthalein anilide type benzoxazine resin (active hydrogen equivalent is 313)

B4: alpha-naphtholphthalein type benzoxazine resin (active hydrogen equivalent is 326)

B5: bisphenol F benzoxazine resin (active hydrogen equivalent of 217)

[ additive flame retardant ]

FR 1: cyclophosphazine (a non-halogen flame retardant, manufactured by pharmaceutical Co., Ltd., Rabbit (Rabbit) FP-100, phosphorus content 13%)

FR 2: DOPO-added BPA (non-halogen flame retardant, manufactured by Shin-AT & C Co., Ltd., LC-9501, phosphorus content 9.2%)

[ others ]

C1: 2-Ethyl-4-methylimidazole (hardening accelerator, manufactured by Siguohuochen chemical industry Co., Ltd., Touzol (Curezol)2E4MZ)

C2: boric acid (manufactured by Sigma-Aldrich Japan)

C3: epoxy silane coupling agent (KBM-403, manufactured by shin-Etsu chemical Co., Ltd.)

[ Filler ]

FL 1: fused silica (SO-C2, manufactured by Admatech technologies, Ltd., average particle diameter: about 0.4 to 0.6 μm)

Example 1

100 parts of epoxy resin (PE1), 48.3 parts of phenol resin (H1), 52.5 parts of oxazine resin (B1) and 0.5 part of C2 are prepared into a 20% methanol solution. In the preparation, the varnish in which methyl ethyl ketone is dissolved is charged with an epoxy resin, a phenol resin and an oxazine resin, and the nonvolatile content is adjusted to 48% to 50% by methyl ethyl ketone and methoxypropanol. Then, the gel time in the varnish was adjusted to 200to 350 seconds at 170 ℃ using a methoxypropanol solution of C1 to obtain an epoxy resin composition varnish.

After 30.1 parts of C was put into the obtained epoxy resin composition varnish, 23 parts of FL1 was put into the varnish separately while being subjected to shear stirring at 5000rpm by using a homomixer, and the mixture was uniformly dispersed for about 10 minutes.

The obtained varnish of the epoxy resin composition was impregnated in glass cloth (manufactured by Nidong textile Co., Ltd., WEA 7628 XS13, thickness 0.18mm), and then the glass cloth was dried for 7 minutes by using a full-vented drying oven at 150 ℃ to obtain a prepreg. The obtained prepreg was stacked in 8 sheets, and further stacked in copper foils (3 EC, thickness 35 μm) one on top of the other, and preheated at 130 ℃ for 15 minutes by a vacuum press, and then press-formed at 2MPa under curing conditions of 240 ℃ and 80 minutes to obtain a laminate sheet having a thickness of about 1.6 mm. The results of the tests on Tg, PCT solder heat resistance test, flame retardancy, copper foil peel strength, interlayer adhesion, and dielectric characteristics of the obtained laminate sheet are shown in table 1.

Examples 2 to 14

A laminated sheet was obtained by blending the components in the amounts (parts) shown in table 1 and performing the same operation as in example 1. The same test as in example 1 was carried out, and the results are shown in table 1.

Comparative examples 1 to 11

A laminated sheet was obtained by blending the components in the amounts (parts) shown in table 2 and performing the same operation as in example 1. The same test as in example 1 was carried out, and the results are shown in table 2.

[ Table 1]

The epoxy resin compositions of examples provide high heat resistance with a Tg of 220 ℃ or higher while the flame retardancy maintains V-0, and also show superiority in dielectric characteristics and adhesion, as compared with the epoxy resin compositions of comparative examples. On the other hand, in the comparative examples, Tg and the compatibility of flame retardancy, dielectric characteristics and adhesion were not maintained.

Claims

1. An epoxy resin composition comprising a phosphorus-containing epoxy resin, an oxazine resin and a phenolic resin having an alicyclic structure, wherein

An oxazine equivalent of 230g/eq or more, a phosphorus-containing epoxy resin obtained from a novolac-type epoxy resin having a ratio L/H of a content L of a trinuclear substance to a content H of a heptanuclear substance or more, which is measured by gel permeation chromatography, in the range of 0.6 to 4.0, a unit of L and H being an area%, an average number Mn/E of functional groups obtained by dividing a number-average molecular weight Mn obtained by a standard polystyrene equivalent by an epoxy equivalent E being in the range of 3.8 to 4.8, and a phosphorus compound represented by general formula (1) and/or general formula (2), and a phosphorus content of the epoxy resin composition being in the range of 0.5 to 1.8 mass%,

in the formula, R¹And R²Each independently represents a C1-20 hydrocarbon group which may have a hetero atom, may be different or the same, and may be linear, branched or cyclic, or may form R¹And R²A bonded cyclic structure; k1 and k2 are each independently 0 or 1; a is an aryltriyl group having 6 to 20 carbon atoms.

2. The epoxy resin composition according to claim 1, wherein the oxazine resin has an oxazine resin represented by the following general formula (3),

in the formula, R³Each independently is an aromatic ring radical, R⁴Are independently hydrogen atom or C1-20 alkyl, and can form two R in the same benzene ring⁴A linked ring structure; r⁵Each independently represents a hydrogen atom or a hydrocarbon group having 1 to 20 carbon atoms; y is-O-or-N (R)⁶)-，R⁶Is a hydrocarbon group having 1 to 20 carbon atoms; z is-CO-or-SO₂-。

3. The epoxy resin composition according to claim 1, wherein the alicyclic structure-containing phenol resin has an alicyclic structure-containing phenol resin represented by the following general formula (4),

wherein T is a divalent aliphatic cyclic hydrocarbon group, X is an aromatic ring group selected from a benzene ring, a naphthalene ring, a biphenyl ring, or a biphenyl structure, and the aromatic ring group may have an alkyl group having 1 to 6 carbon atoms, an alkoxy group having 1 to 6 carbon atoms, an aryl group having 6 to 10 carbon atoms, an aryloxy group having 6 to 10 carbon atoms, an aralkyl group having 7 to 12 carbon atoms, or an aralkyloxy group having 7 to 12 carbon atoms; i is an integer of 1-3; n is a number of 1 to 10 on the average.

4. The epoxy resin composition according to any one of claims 1 to 3, further comprising one or a combination of an inorganic filler, a hardening accelerator, a silane coupling agent, a reinforcing agent, a solvent.

5. A prepreg characterized by using the epoxy resin composition as described in any one of claims 1 to 4.

6. A laminate comprising the epoxy resin composition according to any one of claims 1 to 4.

7. A laminate, characterized in that the prepreg according to claim 5 is used.

8. A printed circuit board characterized by using the epoxy resin composition as claimed in any one of claims 1 to 4.

9. A printed circuit board, characterized in that the laminate as claimed in claim 6 or 7 is used.

10. A cured product obtained by curing the epoxy resin composition according to any one of claims 1 to 4.