TW201343775A - Epoxy resin composition, resin sheet, cured product and phenoxy resin - Google Patents

Abstract

An epoxy resin composition is provided, which contains (a) epoxy resin, (b) curing agent and (c) amorphous phenoxy resin. The amorphous phenoxy resin is represented by the following formula (1) and the weight-average molecular weight of which ranges between 10, 000 and 200, 000. [In the formula (1), the X means a biphenylene skeleton represented by the following formula (2) or a naphthalene skeleton represented by the following formula (3); the Y means a biphenylene skeleton represented by the following formula (2); the Z means a hydrogen atom or a glycidyl group; the n means the number of repeating unit.] [In the formula (2), R1 to R8 each independently means a hydrogen atom or a linear or branched alkyl group having 1 to 4 carbon atoms] In the (a) epoxy resin, a crystalline epoxy resin having a mesogenic group is contained in the range of 5 to 100% by weight based on the total amount of the (a) epoxy resin.

Description

Epoxy resin composition, resin sheet, cured product and phenoxy resin

The present invention relates to an epoxy resin composition for use in the field of electronic materials, a resin sheet and a cured product using the epoxy resin composition, and a phenoxy resin used for the epoxy resin composition.

Since epoxy resin is excellent in adhesiveness, heat resistance, and moldability, it is widely used for electronic parts, electrical equipment, automatic vehicle parts, fiber-reinforced plastic (FRP), sporting goods, etc., for example. In particular, in recent years, epoxy resins are one of the materials that are of great interest in the field of electronic materials (for example, Non-Patent Document 1).

In the field of electronic materials, there is a problem that the wafer generates heat due to the high integration of electronic circuits or the increase in the amount of electric power to be operated, and the problem of errors or malfunctions of signals due to the heat, and the development of heat dissipation technology becomes urgent. Question. In order to solve this problem, a ceramic substrate has been used in the past, but it has the disadvantage of being inferior in workability or productivity, and high in cost. Therefore, an insulating layer containing a resin or the like is disposed in a metal substrate, and then a metal base substrate on which wiring or packaging is applied is performed. The metal Although the base substrate ensures a certain market, higher thermal conductivity is required for the resin to be used under more severe operating conditions, specifically high voltage or high current.

In order to improve the thermal conductivity of the epoxy resin, a method of forming an alignment in the resin during curing of the epoxy resin to improve thermal conductivity is proposed (for example, Non-Patent Document 2). However, the epoxy resin having a high alignment property is also strong in crystallinity, and the monomer is easily precipitated in a crystal form in a state of being varnish dissolved in a solvent. Therefore, there is a possibility that a uniform resin composition cannot be obtained and a curing failure is caused. . Further, an epoxy resin composition containing an epoxy resin monomer having a biphenyl group or a biphenyl derivative, a divalent or higher phenol having at least a meridional group in the ortho position, and a hardening accelerator (for example) is also proposed. Patent Document 1). The thermal conductivity of the cured product using the epoxy resin composition is improved, but a specific solution to the problem of precipitation of crystals in the state of the varnish is not shown.

Prior art literature

Non-patent literature

Non-Patent Document 1: Electronic Equipment Packaging Society, Printed Circuit Technology Handbook, Third Edition (2006)

Non-Patent Document 2: Crushing, No. 55 (2012), p32 to 37

Patent literature

Patent Document 1: Japanese Patent Laid-Open Publication No. 2003-137971

As described above, the resin having high thermal conductivity has a highly symmetrical molecular design in order to secure the alignment property in the cured product, and the monomer has strong crystallinity. therefore, Even if the resin is dissolved in a solvent, the crystal component does not dissolve and remains, and there is a concern that hardening is caused at the time of curing. Therefore, an object of the present invention is to provide a resin composition which does not precipitate in a state of a varnish dissolved in a solvent and which has excellent thermal conductivity in a cured product state.

In order to solve the problem, the inventors of the present invention conducted intensive studies to improve the solubility of the epoxy resin in the varnish state, and as a result, found that an amorphous phenoxy resin having a specific structure is added to the epoxy resin. In addition, precipitation of crystals of the epoxy resin in the varnish can be prevented. Further, it has been found that the above amorphous phenoxy resin does not precipitate crystals in the varnish, but becomes a uniform resin solution, and the amorphous phenoxy resin exhibits a more specific benzene than the general benzene. The high thermal conductivity of the oxyresin.

That is, the epoxy resin composition of the present invention contains the following components (a) to (c): (a) an epoxy resin, (b) a curing agent, and (c) a compound represented by the following formula (1). The amorphous phenoxy resin having a weight average molecular weight in the range of 10,000 to 200,000. In the epoxy resin composition, the component (a) contains a crystalline ring having a mesogenic group in a range of 5 to 100% by weight based on the total amount of the component (a). In the oxy resin, the component (c) is contained in an amount of from 5 parts by weight to 90 parts by weight based on 100 parts by weight of the total of the solid components in the components (a) and (c).

In the formula (1), X represents a biphenylene skeleton represented by the following formula (2) or an extended naphthyl skeleton represented by the following formula (3), and Y represents a formula (2) below. The extended biphenyl skeleton, Z represents a hydrogen atom or a glycidyl group, and n represents the number of repeating units]

In the formula (2), R ₁ to R ₈ each independently represent a hydrogen atom or a linear or branched alkyl group having 1 to 4 carbon atoms.

In the epoxy resin composition of the present invention, the above liquid crystal nucleus may be extended biphenyl base.

In the epoxy resin composition of the present invention, the liquid crystal primordium may be an anthranyl group.

In the epoxy resin composition of the present invention, the component (c) may be an amorphous phenoxy resin having a stretching biphenyl skeleton represented by the above formula (2) in the above formula (1). .

In the epoxy resin composition of the present invention, in the above formula (1), X may be an alkyl group having at least four of R ₁ to R ₈ in the above formula (2) and having a carbon number of 4 or less. The extension of the atom to the phenyl skeleton.

In the epoxy resin composition of the present invention, in the above formula (1), Y may be an unsubstituted extended biphenyl skeleton in which all of R ₁ to R ₈ in the above formula (2) are hydrogen atoms.

In the epoxy resin composition of the present invention, in the above formula (1), X may be a tetraalkyl-terminated biphenyl group having an alkyl group having 4 or less carbon atoms substituted at the 3,3'-position and the 5,5-position. Y may be an unsubstituted extended biphenyl group.

In the epoxy resin composition of the present invention, the component (c) may be an amorphous phenoxy resin having an extended naphthyl skeleton represented by the above formula (3) in the above formula (1).

In the epoxy resin composition of the present invention, in the above formula (1), X may be a stretching naphthyl skeleton having a single bond at the 1-position and the 6-position, and Y may be R ₁ in the above formula (2). R ₈ is an unsubstituted extended biphenyl skeleton which is a hydrogen atom.

The epoxy resin composition of the present invention may further contain the following components (d): (d) an inorganic filler.

The epoxy resin composition of the present invention may further contain the following component (e): (e) a solvent.

The resin sheet of the present invention is obtained by forming any of the above epoxy resin compositions into a film form.

The cured product of the present invention is obtained by curing any of the above epoxy resin compositions.

The phenoxy resin of the present invention has a tetramethyl-terminated biphenyl group substituted with a methyl group at the 3,3'-position and the 5,5-position, and an unsubstituted extended biphenyl group, and has a weight average molecular weight of 10,000. In the range of ~200,000.

In the phenoxy resin of the present invention, the molar ratio of the tetramethyl-terminated biphenyl group substituted with a methyl group at the 3,3'-position and the 5,5-position to the unsubstituted extended biphenyl group is substantially It is 1:1.

In the epoxy resin composition of the present invention, the amorphous epoxy resin represented by the formula (1) and the amorphous phenoxy resin represented by the formula (1) are blended and the epoxy resin is dissolved in a solvent. Precipitation of crystals in the varnish is prevented, and excellent thermal conductivity can be imparted to the cured product. In other words, by blending the amorphous phenoxy resin represented by the formula (1), the crystalline epoxy resin having a liquid crystal priming group can be melted, and a uniform resin composition can be obtained in the state of varnish. By coating, drying, and The molding process of the resin sheet or the like can be easily performed. Further, the cured product which hardens the epoxy resin composition has excellent thermal conductivity. Therefore, the epoxy resin composition of the present invention can provide a molded article or a cured product such as a curable resin sheet having excellent thermal conductivity, a curable high heat dissipating resin sheet, an insulating sheet, a prepreg, and an adhesive film.

The epoxy resin composition of the present embodiment contains the above components (a) to (c). Hereinafter, each component will be described.

<(a) component: epoxy resin>

Examples of the epoxy resin as the component (a) include a biphenyl type epoxy resin, a naphthalene type epoxy resin, a bisphenol A type epoxy resin, a bisphenol F type epoxy resin, and a bisphenol S type epoxy resin. , phenol novolak type epoxy resin, o-cresol novolac type epoxy resin, biphenyl novolac type epoxy resin, triphenylmethane type epoxy resin, dicyclopentadiene type epoxy resin, alicyclic type An epoxy resin having two or more epoxy groups in a molecule such as an epoxy resin or a brominated epoxy resin. These epoxy resins may be used alone or in combination of two or more.

In the component (a), it is preferred to contain a crystalline epoxy resin having a liquid crystal nucleus in a range of 5 to 100% by weight based on the total amount of the component (a). When the content of the crystalline epoxy resin having a liquid crystal primordium in the component (a) is less than 5% by weight, the thermal conductivity of the cured product may be lowered. Here, the crystalline epoxy resin having a liquid crystal priming unit is a solid epoxy resin having a softening point of 40 ° C or higher. By using A crystalline epoxy resin having a liquid crystal priming agent imparts excellent thermal conductivity to the cured product. As the liquid crystal priming group, for example, a biphenyl group, a naphthyl group or the like is preferable. Therefore, as the crystalline epoxy resin having a liquid crystal priming group, the biphenyl type epoxy resin or the naphthalene type epoxy resin is preferable. In addition, the crystallinity means that in the differential scanning calorimetry (DSC), the endothermic peak temperature based on the melting point can be confirmed. Specific examples of the crystalline epoxy resin having a liquid crystal priming group include GK-3007 (biphenyldiphenol aralkyl type epoxy resin) manufactured by Nippon Steel & Sumitomo Chemical Co., Ltd., Mitsubishi Chemical Corporation Manufactured YX-4000 (tetramethylbiphenyldiphenol type epoxy resin), YL-6121H manufactured by Mitsubishi Chemical Corporation, and NC-3000 (extended biphenyl aralkylphenol) manufactured by Nippon Kayaku Co., Ltd. Epoxy resin), EPPN-501H (triphenylmethane epoxy resin) manufactured by Nippon Kayaku Co., Ltd., etc.

The content of the epoxy resin of the component (a) is, for example, preferably in the range of 10 parts by weight to 95 parts by weight based on 100 parts by weight of the total of the solid components in the component (a) and the component (c). It is preferably in the range of 30 parts by weight to 90 parts by weight. When the content of the epoxy resin of the component (a) is more than 95 parts by weight based on 100 parts by weight of the solid component, the workability of the epoxy resin composition in the B-stage state is lowered, or the cured product becomes brittle and sticky. A decrease in relay force, a decrease in heat resistance, and a decrease in temperature cycle resistance. When the component (a) is a crystalline epoxy resin, when the content of the epoxy resin of the component (a) exceeds the above upper limit, the solvent solubility is lowered, and the epoxy resin composition is less likely to be formed into a film. On the other hand, when the content of the epoxy resin of the component (a) is less than 10 parts by weight based on 100 parts by weight of the solid component, The curing of the epoxy resin composition is insufficient, and the adhesive strength is lowered or the heat resistance is lowered. When the component (a) is a crystalline epoxy resin, when the content of the epoxy resin of the component (a) is less than the above lower limit, the resin sheet in the B-stage state is hard and is easily broken.

In addition, the solid component in the component (a) and the component (c) is, for example, a process of forming a cured adhesive layer such as an insulating layer using the varnish when the epoxy resin composition contains a varnish having a specific solvent. In the case, the solid component in the component (a) and the component (c) remaining after the solvent is removed by drying or hardening. Here, the varnish is a solvent containing a solvent in order to reduce the viscosity of the epoxy resin composition and to improve the workability, and after applying the obtained varnish to a substrate or the like, it is dried to obtain a resin sheet in a B-stage state. Further, after the obtained varnish is impregnated into a glass cloth or the like, it is dried to obtain a prepreg. The solvent is removed by these drying steps. Finally, after forming a cured material such as an insulating adhesive layer, the solvent is removed by drying and heat treatment. Therefore, the content rate of the component in the epoxy resin composition of the present embodiment is defined by the total component content ratio of the solid components in the component (a) and the component (c). Further, when an optional component is blended in the epoxy resin composition of the present embodiment, an arbitrary component is included and can be calculated based on the solid content of the entire epoxy resin composition. In addition, the degree of solvent removal can also control the solvent remaining in the design within the manufacturing step.

<(b) component: hardener>

The curing agent of the component (b) is prepared by curing the epoxy resin, and when the insulating layer, the adhesive layer or the resin film is formed of the epoxy resin composition, sufficient Insulation, adhesion, heat resistance, mechanical strength, etc. As the curing agent of the component (b) used in the embodiment, an imidazole-based curing agent or a non-imidazole-based curing agent can be used.

The imidazole-based hardener preferably contains only an imidazole compound. The imidazole-based curing agent can suppress the increase in the viscosity of the epoxy resin composition, and the handling of the epoxy resin composition after the preparation becomes relatively easy. Examples of the imidazole compound include 2-methylimidazole, 2-undecylimidazole, 2-heptadecylimidazole, 2-ethyl-4-methylimidazole, 2-phenylimidazole, and 4-methyl. Phen-2-phenylimidazole, 2-phenyl-4,5-dihydroxymethylimidazole, 2-phenyl-4-methyl-5-hydroxymethylimidazole, and the like.

Among the above imidazole compounds, 2-phenyl-4,5-dihydroxymethylimidazole is most preferably used. 2-Phenyl-4,5-dihydroxymethylimidazole is a highly potent hardener, and has a characteristic that it does not undergo a hardening reaction in the drying step at the time of preparation of the resin sheet in the B-stage state, and is further stored during long-term storage. Excellent stability.

The imidazole compound is usually blended as a curing accelerator in a resin composition containing an epoxy resin as a main component. However, in the epoxy resin composition of the present embodiment, when an imidazole-based curing agent is used, since a curing agent component other than the imidazole compound is not used, an anion polymerization starting from an imidazole compound can be used to form a ring. The oxygen resin composition hardens. Due to such a reaction property, the imidazole compound can function as a curing agent in the epoxy resin composition of the present embodiment, and can be used as compared with a reaction system in which a addition curing agent component is blended. The amount of the compound as a hardener is suppressed at a low level. Since the imidazole compound is a catalyst-type hardener, for example, if a curing hardener component such as dicyandiamide or a novolak-type phenol resin is present, a curing agent component and a ring are added. The oxygen resin preferentially reacts, and it is difficult to cause a single condensation reaction of the epoxy resin.

The content ratio of the imidazole-based curing agent containing the imidazole compound as the component (b) is, for example, preferably 0.01 parts by weight to 10 parts by weight based on 100 parts by total of the solid components in the components (a) to (c). It is more preferably in the range of 0.01 part by weight to 5 parts by weight in the range of parts by weight. When the content of the imidazole-based curing agent is more than 10 parts by weight, there is a concern that a halogen element derived from an epoxy resin is induced as a halogen ion. On the other hand, when the content of the imidazole-based curing agent is less than 0.01 parts by weight, the curing reaction does not proceed sufficiently, and the adhesive strength is lowered, or the curing time is prolonged, and the usability is lowered.

On the other hand, examples of the non-imidazole-based curing agent include a novolac type phenol resin, dicyandiamide, diaminodiphenylmethane, and diaminodiphenylphosphonium, which are known as curing agents for epoxy resins. By. The non-imidazole-based curing agent is preferably formulated so as to have an equivalent ratio ((b)/(a)) of 0.5 to 1.5 with respect to the epoxy resin of the component (a). In general, when a phenol resin-based curing agent is used, it can be in the range of 0.8 to 1.2, and when an amine-based curing agent is used, it can be in the range of 0.5 to 1.0.

When a non-imidazole-based curing agent is used, it is preferable to contain a curing accelerator in addition to the components (a) to (c). As the curing accelerator, for example, an organic phosphorus compound such as triphenylphosphine or an imidazole such as 2-phenylimidazole or 2-ethyl-4-methylimidazole can be used. The blending ratio is appropriately selected in accordance with the required curing time, and is usually in the range of 0.01 to 3.0 parts by weight based on 100 parts by weight of the total of the solid components in the components (a) to (c).

<(c) Amorphous phenoxy resin>

The amorphous phenoxy resin of the component (c) has a stretched phenyl skeleton or a naphthyl skeleton. The amorphous phenoxy resin prevents the precipitation of crystals when the epoxy resin composition is in a varnish state, maintains the dissolution state in the organic solvent, and improves the formation of the insulating layer and the adhesive layer from the epoxy resin composition. Or a flexible component in the case of a resin film.

The amorphous phenoxy resin having a stretched biphenyl skeleton or an extended naphthyl skeleton is represented, for example, by the following general formula (1). In the formula (1), X represents a stretching biphenyl skeleton represented by the following formula (2) or a stretching naphthyl skeleton represented by the following formula (3), and Y represents an extension shown by the following formula (2). A phenyl skeleton, Z represents a hydrogen atom or a glycidyl group, and n is a number indicating a repeating unit.

In the formula (2), R ₁ to R ₈ each independently represent a hydrogen atom or a linear or branched alkyl group having 1 to 4 carbon atoms. In the amorphous phenoxy resin of the component (c), the ratio of X to Y is about 1:1, but the contents of X and Y may be slightly different. In general, the molecular weight of the amorphous phenoxy resin of the component (c) is designed by the molar ratio of the compound to be a raw material, and the target molecular weight is obtained while controlling the reaction temperature and the reaction time. It can be designed such that the terminal end of the main chain becomes an epoxy group or a phenolic hydroxyl group, depending on the molar ratio of the raw material used. The amorphous phenoxy resin represented by the formula (1) is substantially the same compound as the epoxy resin, but has different properties due to the difference in molecular weight, and is therefore referred to separately. That is, the epoxy resin means a small molecular weight; the phenoxy resin means a molecular weight. There is no obvious boundary, and a person having a weight average molecular weight of 10,000 or more is generally referred to as a phenoxy resin. When the molecule of the phenoxy resin is large, the epoxy group which is a reaction point is relatively small, and therefore, as a characteristic of a thermosetting resin, the characteristic as a thermoplastic resin is more strongly expressed, and therefore, it is compatible with an epoxy resin. the difference. Epoxy resin and phenoxy resin can be produced separately according to the purpose. Further, since the epoxy resin described in Patent Document 1 has an average molecular weight of about 300 to 400, it is an epoxy resin if classified according to the above.

The weight average molecular weight of the amorphous phenoxy resin of the component (c) is, for example, in the range of 10,000 to 200,000, more preferably in the range of 20,000 to 100,000. When the weight average molecular weight of the amorphous phenoxy resin is less than 10,000, the self-made film property is lacking, and the sheet or film becomes brittle, so that it is difficult to handle. Further, when the weight average molecular weight exceeds 200,000, there arises a problem that the amorphous phenoxy resin becomes difficult to dissolve in the solvent or the viscosity of the resin solution becomes high. Further, the weight average molecular weight herein is a value in terms of polystyrene measured by gel permeation chromatography (GPC).

Preferable examples of the amorphous phenoxy resin as the component (c) include those in which both X and Y in the formula (1) are a biphenyl group represented by the formula (2). In this case, at least for X, in the formula (2), at least four of R ₁ to R ₈ are an alkyl group having 4 or less carbon atoms, and the rest are hydrogen atoms, and Y is preferably the same as X. The substituent, or preferably an unsubstituted extended biphenyl skeleton in which all of R ₁ to R ₈ in the formula (2) are a hydrogen atom. That is, as the amorphous phenoxy resin as the component (c), for example, X in the formula (1) is preferably at the 3, 3' position and the 5, 5' position, or the 2, 2' position and 6 a 6-position of an alkyl group having a carbon number of 4 or less, wherein the Y is the same as X, for example, at the 3, 3' position and the 5, 5' position, or the 2, 2' position and 6, a 6-position of an alkyl group having a carbon number of 4 or less, or an unsubstituted diphenylene skeleton; more preferably, the alkyl group having 4 or less carbon atoms is a methyl group, and the weight is The phenoxy resin having an average molecular weight in the range of 10,000 to 200,000. In addition, the amorphous phenoxy resin of the component (c) in the solvent is inhibited from being solidified or crystallized by introducing a substituted biphenyl skeleton having a substituent, and is introduced more without impairing the degree of amorphousness. From the viewpoint of the unsubstituted (all hydrogen-substituted) diphenylene skeleton, it is particularly preferred that X in the formula (1) is 3,3',5,5'-tetramethyl-terphenyl, Y It is an unsubstituted biphenyl.

Further, as another preferable example of the amorphous phenoxy resin as the component (c), X in the formula (1) is a stretching naphthyl skeleton represented by the formula (3), and Y is a formula (2). The extended biphenyl skeleton shown. In this case, with respect to X, it is preferred that the position of the single bond of the stretching naphthyl skeleton in the formula (3) is asymmetrical, and Y is preferably such that all of R ₁ to R ₈ in the formula (2) are hydrogen atoms. Substituted biphenyl skeleton. Here, as a specific example of the position of the single bond of the stretching naphthyl skeleton, it is preferred that the 1- and 6-positions, or the 1-position and the 7-position of the stretching naphthyl skeleton in the formula (3) have a single bond, respectively. By. When the position of the single bond of the naphthyl skeleton is asymmetric, the molecular chain is difficult to align due to structural defects, and thus a liquid phenoxy resin which is soluble in a solvent can be obtained. On the other hand, for example, in the case where the single bond is present at the 2-position and the 7-position in the formula (3), if the symmetry is high, the phenoxy resin is cured or crystallized in a solvent, and it is difficult to obtain. Liquid phenoxy resin. Therefore, as the amorphous phenoxy resin of the component (c), X in the formula (1) is preferably a stretching naphthyl skeleton having a bonding bond at an asymmetric position, and Y is an unsubstituted extended biphenyl. The base skeleton is more preferably a phenoxy resin having a weight average molecular weight in the range of 10,000 to 200,000.

For example, the content of the amorphous phenoxy resin of the component (c) is preferably in the range of 5 parts by weight to 90 parts by weight based on 100 parts by weight of the total of the solid components in the component (a) and the component (c). More preferably, it is in the range of 10 parts by weight to 70 parts by weight. When the content of the amorphous phenoxy resin is more than 90 parts by weight based on 100 parts by weight of the total of the solid components, the viscosity at the time of varnish formation increases, and the workability of the insulating layer or the adhesive layer is improved. The adhesiveness is lowered, or the surface state is deteriorated, and the heat resistance is also lowered. In addition, when the resin sheet is formed, it is hard and easily broken. The operability is lowered. On the other hand, when the content of the amorphous phenoxy resin is less than 5 parts by weight based on 100 parts by weight of the total of the solid components, the crystal of the epoxy resin of the component (a) precipitates in the varnish state, and becomes Causes poor hardening.

In the epoxy resin composition of the present embodiment, the amorphous phenoxy resin in which the component (c) is blended is blended with an epoxy resin containing the component (a) having a crystalline epoxy resin having a liquid crystal nucleus. On the other hand, it is possible to impart excellent thermal conductivity to the cured product while effectively preventing the formation of crystals in the state of the varnish. For this purpose, the ratio of the component (c) in the epoxy resin composition of the present embodiment to the crystalline epoxy resin having a liquid crystal primordium of the component (a) has the ratio [(c)/(a) The crystalline epoxy resin of the liquid crystal original is preferably in the range of 0.35 to 10, for example. When the ratio of the crystalline epoxy resin having a liquid crystal priming in [(c)/(a)] is less than 0.35, the effect of suppressing precipitation of crystals in the state of varnish is lowered. On the other hand, when the above compounding ratio exceeds 10, the solubility of the epoxy resin composition in the organic solvent is lowered.

The amorphous phenoxy resin represented by the formula (1) can be produced, for example, by an epoxy compound having two epoxy groups in one molecule represented by the following formula (4). A method of reacting a compound having two aromatic hydroxyl groups in one molecule represented by the following formula (5) in the presence of a polymerization catalyst, or having 2 molecules represented by the following formula (5) A well-known and customary method for reacting a compound having an aromatic hydroxyl group with an epihalohydrin in the presence of an alkali metal hydroxide. Further, the epihalohydrin used in the synthesis of the amorphous phenoxy resin is not particularly limited, and for example, epichlorohydrin is preferred. In addition, as an alkali metal hydroxide, There is no particular limitation, and for example, sodium hydroxide is preferred.

HO-Y-OH...(5)

X and Y in the above formulas (4) and (5) have the same meanings as described above. In the above, the epoxy compound having two epoxy groups in one molecule represented by the formula (4) is, for example, YX-4000 (tetramethylbiphenyldiol) ring manufactured by Mitsubishi Chemical Corporation. Oxygen resin), YL-6121H manufactured by Mitsubishi Chemical Corporation, and the like.

<arbitrary composition>

In addition to the above-mentioned essential components, the epoxy resin composition of the present embodiment may be, for example, a solvent, a rubber component, an antifoaming agent such as a fluorine-based or an anthrone, or a leveling agent. In addition, from the viewpoint of improving adhesion between members such as a metal substrate and a copper wiring, for example, an adhesion imparting agent such as a decane coupling agent or a thermoplastic oligomer can be added. Moreover, in the epoxy resin composition of the present embodiment, An inorganic filler or an organic filler may also be added. Examples of the inorganic filler include alumina, cerium oxide, boron nitride, aluminum nitride, cerium nitride, calcium carbonate, and magnesium carbonate. Further, examples of the organic filler include glutinous rice powder, nylon powder, and acrylonitrile-butadiene-based crosslinked rubber. These fillers may be used alone or in combination of two or more. Further, in the epoxy resin composition of the present embodiment, for example, a coloring agent such as phthalocyanine green, phthalocyanine blue or carbon black may be added as needed.

Here, examples of the alumina of the inorganic filler include crystalline alumina and fused alumina, and among them, crystalline spherical alumina powder is particularly preferred. The crystalline alumina is superior in the effect of improving the thermal conductivity as compared with the fused alumina. Further, by using spherical alumina, the effect of lowering the viscosity at the time of varnish formation or the melt viscosity at the time of forming a resin film is also obtained as compared with the crushed alumina. From the viewpoint of achieving high thermal conductivity by the most dense filling, it is preferred to set the spherical sphericity of the spherical alumina powder to 95% or more.

The maximum particle size of the spherical alumina powder has a great influence on thermal conductivity and insulation. A conductive path at the time of voltage application is formed on the surface of the spherical alumina powder. Therefore, when the maximum particle diameter is set so that a plurality of spherical alumina particles can be arranged in the thickness direction of the cured product, the conductive path becomes long, and the insulating portion between the particles also increases, so that the withstand voltage is high, but the heat dissipation property is improved. reduce. Therefore, the maximum particle diameter of the spherical alumina powder is preferably determined in consideration of the balance between the withstand voltage property and the heat dissipation property.

In the epoxy resin composition of the present embodiment, when spherical alumina powder is used as the inorganic filler, it is spherical with respect to the solid content of the epoxy resin composition. The content of the alumina powder is preferably from 50% by weight to 95% by weight, more preferably from 75% by weight to 94% by weight. The higher the content of the spherical alumina powder in the epoxy resin composition, the higher the thermal conductivity and the lower the thermal expansion. When the content of the spherical alumina powder relative to the solid content of the epoxy resin composition is less than 50% by weight, the effect of improving the thermal conductivity may be insufficient, and sufficient heat dissipation may not be exhibited. On the other hand, when the content ratio of the spherical alumina powder to the solid content of the epoxy resin composition is more than 95% by weight, the viscosity at the time of making the varnish is increased, or the melting is performed when the adhesive film is formed. The viscosity is increased, and the workability, the withstand voltage characteristics, the adhesiveness, or the surface state of the insulating adhesive layer are deteriorated.

[varnish]

The epoxy resin composition of the present embodiment can be prepared by mixing the above-mentioned essential components and optional components. In this case, it is preferably set to a form of a varnish containing a solvent. That is, the epoxy resin composition of the present embodiment can be dissolved or dispersed in a specific solvent to form a varnish.

As the solvent usable for the varnish, N,N-dimethylformamide (DMF), N,N-dimethylacetamide, N-methyl-2-pyrrolidone (N-methyl-) can be exemplified. 2-pyrrolidone, NMP) and other guanamine solvents, 1-methoxy-2-propanol and other ether solvents, methyl ethyl ketone, methyl isobutyl ketone (MIBK), cyclohexanone A ketone solvent such as cyclopentanone, or an aromatic solvent such as toluene or xylene, or a mixture of two or more kinds thereof. The hardener of the component (b) and the inorganic filler, the organic filler, the colorant, and the like in any of the components added as needed may be uniformly dissolved in the solvent, so that it is not necessary to be dissolved in the solvent. In the solvent.

The varnish can be prepared, for example, in the order shown below. First, the amorphous phenoxy resin of the component (c) is dissolved in an appropriate solvent while stirring in a vessel with a stirrer. Next, a varnish is prepared by mixing the epoxy resin of the component (a), the curing agent of the component (b), and optional components in the solution, stirring them, or dispersing them uniformly. Further, depending on the type of the epoxy resin of the component (a), a solution in which the epoxy resin is dissolved in a solvent can be prepared in advance and mixed. As described above, the epoxy resin composition of the present embodiment can suppress the crystalline epoxy resin having a liquid crystal priming group by combining a crystalline epoxy resin having a liquid crystal primordium and an amorphous phenoxy resin. Precipitation of crystals in the varnish. Therefore, it is possible to obtain a uniform epoxy resin composition in a state of varnish, and it is easy to mold a resin sheet or the like by coating and drying.

The viscosity of the varnish is preferably 1000 Pa. s~20000 Pa. Within the range of s, more preferably 2000 Pa. s~10000 Pa. Within the scope of s. The viscosity of the varnish is less than 1000 Pa. In the case of s, precipitation of the spherical filler is liable to occur, and unevenness or shrinkage at the time of coating or the like is likely to occur. On the other hand, the viscosity of the varnish is greater than 20,000 Pa. In the case of s, since the fluidity is lowered, the coatability is lowered, and it is difficult to produce a uniform coating film.

[Resin sheet, copper foil with resin sheet]

In the present embodiment, the varnish is applied onto a base film as a support material and dried to form a resin sheet in a B-stage state. Further, the varnish is applied onto a copper foil and dried to form a copper foil with a resin sheet. Resin sheet in the B-stage state (copper foil with resin sheet) if bent If the surface is cracked (cracked), the value of the product will be impaired. The surface crack in such a B-stage state is easily generated by blending a large amount of a crystalline epoxy resin having a liquid crystal priming base which is solid at normal temperature. As described above, the epoxy resin composition of the present embodiment is prepared by combining a crystalline epoxy resin having a liquid crystal primordium and an amorphous phenoxy resin, and the flexibility of the resin sheet is improved, and the varnish is suppressed. The precipitation of crystals can also suppress the occurrence of cracks. Further, in the present embodiment, when only an imidazole compound is used as the curing agent, the ratio of the solid resin component in the epoxy resin composition can be suppressed to a low level. Further, when the imidazole compound is blended with, for example, a phenol novolac-based hardener component, the amount of the curing agent can be suppressed to a low level. Therefore, a larger amount of a component which is liquid or semi-solid at normal temperature can be adjusted, and the flexibility and flexibility in the B-stage state are improved, and the surface crack can be prevented.

In addition, as for the film supportability of the resin sheet or the copper foil with a resin sheet (before curing), the higher the solvent residual ratio, the better the film supportability is. However, when the residual ratio of the solvent is too high, the resin sheet or the copper foil with the resin sheet (before curing) is viscous or foamed at the time of curing. Therefore, the solvent residual ratio is preferably 5% by weight or less. In addition, the solvent residual ratio is a value obtained by measuring the pure weight reduction rate of the resin sheet portion when dried in an environment of 180 ° C for 60 minutes.

Examples of the support material used in forming the resin sheet or the copper foil with the resin sheet include polyethylene terephthalate (PET), polyethylene, copper foil, aluminum foil, release paper, and the like. . The thickness of the support material can be, for example, 10 μm to 100 μm. Use metal foil such as copper foil or aluminum foil When used as a support material, the metal foil can be produced, for example, by an electrolysis method, a calendering method, or the like. Further, in the metal foil, from the viewpoint of improving the adhesion to the insulating layer, it is preferable to roughen the surface on the side in contact with the insulating layer.

Further, the resin sheet or the copper foil with the resin sheet may be attached to the base film as a support material, and the other side which is not in contact with the copper foil may be covered by the film as a protective material, and wound up in a roll shape. And save. Examples of the protective material used at this time include polyethylene terephthalate, polyethylene, release paper, and the like. In this case, the thickness of the protective material can be, for example, in the range of 10 μm to 100 μm.

[hardened material]

The cured product of the present embodiment can be prepared, for example, by preparing a resin sheet (or a copper foil with a resin sheet) in the above-described B-stage state from an epoxy resin composition, for example, heating to a range of 150 ° C to 250 ° C. The internal temperature makes it harden. The cured product thus obtained does not have crystallinity, but has excellent thermal conductivity. In applications requiring high heat conductivity, the thermal conductivity of the cured product is, for example, preferably 10 W/mK or more, more preferably 13 W/mK or more. The cured product has a thermal conductivity of 10 W/mK or more, and is excellent in heat dissipation characteristics, and can be applied to a circuit board or the like used in a high-temperature environment.

[Method of Manufacturing Metal Base Circuit Board]

Next, an example of a method of manufacturing a metal base circuit substrate using the epoxy resin composition of the present embodiment will be described. Here, an aluminum base circuit substrate using an aluminum substrate is exemplified. First, after obtaining the above-mentioned copper foil with a resin sheet from the epoxy resin composition, a batch type vacuum press is used on the aluminum substrate, for example, at a temperature of 150 ° C to 250 ° C and a pressure of 1.0 MPa to 30 ° Under the condition of MPa, with the attached tree The copper foil of the grease sheet is bonded. At this time, the resin sheet surface is brought into surface contact with the aluminum substrate, and the copper foil as the support material is heated and pressurized in a state where the copper foil is placed on the upper surface, and the epoxy resin is cured to be attached to the aluminum substrate. Thus, a laminate in which a resin sheet is used as an insulating adhesive layer and interposed between the copper foil layer and the aluminum substrate can be obtained. Next, the copper wiring of the specific portion is removed by etching to form a circuit wiring, and finally, an aluminum base circuit substrate can be obtained. Further, the thickness of the aluminum substrate is not particularly limited, and is usually, for example, 0.5 mm to 3.0 mm.

When the aluminum base circuit substrate including the copper conductor layer, the insulating adhesive layer, and the aluminum layer is obtained by using the epoxy resin composition of the present embodiment, in addition to the above method, the following method may be employed: After coating and drying on a moldable PET film, the release PET is peeled off, sandwiched between an aluminum substrate and a copper foil, and cured while being heated and pressurized; and an adhesive layer is formed on the surface of the aluminum substrate. a method in which a copper foil is placed on the adhesive layer and cured while being heated and pressurized; or an insulating adhesive layer is formed on the surface of the aluminum substrate to be cured, and then formed by copper plating. A method of a copper conductor layer or the like. Further, as for the formation of the adhesive layer at this time, a method of volatilizing a solvent by heating after applying a varnish, a method of applying a solventless paste, or a method of bonding a resin sheet may be used. Any one.

Example

Hereinafter, the present invention will be specifically described by examples, but the present invention is not limited by these examples. In addition, in the following examples, unless otherwise indicated, various measurements and evaluations are as follows.

[Weight average molecular weight of phenoxy resin]

The weight average molecular weight of the phenoxy resin was analyzed using gel permeation chromatography. Specifically, a pipe string, TSK-gel GMHXL, TSK-gel GMHXL, and TSK-gel G2000H manufactured by Tosoh Corporation are arranged in tandem in the HLC-8320 body manufactured by Tosoh Co., Ltd. Further, the solution was a tetrahydrofuran, and the flow rate was set to 1 ml/min. The temperature of the column chamber was set to 40 degrees. Detection was performed using a refractive index (RI) detector. The weight average molecular weight was determined using a standard polystyrene standard curve.

[nonvolatile content of phenoxy resin solution]

The non-volatile component of the phenoxy resin solution is obtained by weighing about 1 g of the sample in an aluminum cup, and drying in a hot air circulating oven at 200 ° C for 1 hour, and calculating the non-volatile matter according to the weight remaining without volatilization. ingredient.

[Evaluation of Crystallinity of Crystalline Epoxy Resin Having Liquid Crystalline Priming Group]

The evaluation of the crystallinity of the crystalline epoxy resin having a liquid crystal nucleus is carried out by adding 100 parts by weight of acetone to 100 parts by weight of the crystalline epoxy resin having a liquid crystal nucleus, and then insoluble matter and precipitates are dissolved. It was separated and dried to obtain a solid matter. The obtained solid matter was subjected to differential scanning calorimetry, and the crystallinity was evaluated by confirming whether or not the endothermic peak temperature based on the melting point was confirmed.

[Thermal conductivity]

Using a specific amount of the B-stage resin sheet, heating at 180 ° C for 10 minutes by a compression press molding machine, taking it out from the press, followed by heating at 180 ° C for 50 minutes in a dryer, thereby obtaining a diameter of 50 mm, thickness It is a 5 mm disc-shaped test piece. Make The thermal conductivity measuring device HC-110 manufactured by Yinghong Seiki was used to measure the thermal conductivity at 25 ° C [W/m. K].

Synthesis Example 1-1

In a separable flask equipped with a stirrer, a nitrogen gas inlet, a reflux port having a pressure reducing device and a cooler, and a water-water separation tank, and an alkali metal hydroxide aqueous solution dropping port, 300 parts by weight of 1,6-dihydroxynaphthalene is added. 1387.5 parts by weight of epichlorohydrin and 208.1 parts by weight of HYSORB MDM were heated to 60 ° C after being purged with nitrogen, and then dissolved, and 31.1 parts by weight of a 48.8 wt% aqueous solution of sodium hydroxide was added while being heated, and reacted for 1 hour. Then, the introduction of nitrogen gas was stopped, and 290.0 parts by weight of a 48.8 wt% aqueous solution of sodium hydroxide was added dropwise over 8 hours under conditions of 160 Torr and 63 °C. After the completion of the dropwise addition, the temperature was raised to 150 ° C, and then the pressure was reduced to 10 Torr to remove epichlorohydrin and HYSORB MDM. After adding toluene to the obtained resin, it was filtered using diatomaceous earth, washed with a 0.1% by weight aqueous solution of sodium hydroxide, and then subjected to oil-water separation to remove the aqueous phase. Next, after adding water and washing, oil-water separation is performed and the water phase is removed. Water and toluene were removed from the obtained resin solution to obtain a diglycidyl ether type epoxy resin of 1,6-dihydroxynaphthalene. The resulting epoxy resin was a brown liquid with an epoxy equivalent of 143.8 g/eq.

Synthesis Example 1-2

The diglycidyl ether epoxy resin of the 1,6-dihydroxynaphthalene obtained in Synthesis Example 1-1 was added to a separable flask equipped with a stirrer, a nitrogen gas inlet, a thermocouple, and a reflux port of a cooling machine. Parts by weight, 38.8 parts by weight of 4,4'-biphenol and 25 parts by weight of cyclohexanone were heated to 145 ° C, dissolved, and stirred for 1 hour. Then join 0.1 parts by weight of tris-(2,6-dimethoxyphenyl)phosphine as a reaction catalyst was heated to 165 °C. As the reaction progressed, the viscosity increased, but stirring was continued in such a manner that cyclohexanone was appropriately added to become a fixed torque. The reaction was followed by gel permeation chromatography, and when a specific weight average molecular weight was reached, cyclohexanone was added for cooling, and the reaction was stopped. The resulting solution was homogeneous and had a solid content of 30.5 wt%. The obtained phenoxy resin was a pale brown liquid having an epoxy equivalent of 5,750 g/eq, a number average molecular weight of 7,800, and a weight average molecular weight of 47,600.

Synthesis Example 2-1

A diglycidyl ether type epoxy resin of 2,7-dihydroxynaphthalene was obtained by the same procedure as in Synthesis Example 1-1 except that 2,7-dihydroxynaphthalene was used. The obtained resin was a brown liquid, but had crystallinity and became a white solid. In addition, its epoxy equivalent was 145.0 g/eq.

Synthesis Example 2-2

56.7 parts by weight of 2,7-dihydroxynaphthalene diglycidyl ether type epoxy resin obtained in Synthesis Example 2-1 which is an epoxy resin having an extended naphthyl skeleton, and 43.3 parts by weight of bisphenol A, in addition to In the same procedure as in Synthesis Example 1-2, when the weight average molecular weight was about 40,000, the reaction was terminated to obtain a solution having a solid content of 30.5 wt%. The obtained phenoxy resin was a pale brown liquid and had a weight average molecular weight of 44,600.

Synthesis Example 2-3

A diglycidyl ether type epoxy resin of 1,5-dihydroxynaphthalene was obtained by the same procedure as in Synthesis Example 1-1 except that 1,5-dihydroxynaphthalene was used. Synthetic time The crystal is kept in such a manner that the crystal does not precipitate. The obtained resin had crystallinity and became a white solid. In addition, its epoxy equivalent was 149.3 g/eq.

Synthesis Example 3-1

In a 2000 ml four-necked flask, 186.0 g (1.0 mol) of 4,4'-dihydroxybiphenyl and 600 g of diethylene glycol dimethyl ether were added, and the temperature was raised to 150 ° C while stirring under a nitrogen stream. A solution in which 52.5 g (0.3 mol) of 1,4-dichloromethylbenzene was dissolved was added dropwise to 260 g of diethylene glycol dimethyl ether, and the mixture was heated to 170 ° C and reacted for 2 hours. After the reaction, it was added dropwise to a large amount of pure water and recovered by reprecipitation to obtain 202 g of a pale yellow and crystalline resin.

Synthesis Example 3-2

115 g of the resin obtained in Synthesis Example 3-1 was dissolved in 549 g of epichlorohydrin and 82.4 g of diethylene glycol dimethyl ether, and 48% of hydrogen was added dropwise at 62 ° C for 4 hours under reduced pressure (about 130 Torr). The aqueous sodium oxide solution was 82.4 g. During this period, the produced water was removed to the outside of the system by azeotropy with epichlorohydrin, and the distilled epichlorohydrin was returned to the system. After the completion of the dropwise addition, the reaction was continued for 1 hour. Then, epichlorohydrin was distilled off, and after adding 966 g of methyl isobutyl ketone, the salt was removed by washing with water. Then, 19.2 g of a 24% aqueous sodium hydroxide solution was added, and the mixture was reacted at 85 ° C for 2 hours. After the reaction, the mixture was filtered and washed with water, and then methyl isobutyl ketone as a solvent was distilled off under reduced pressure to obtain 145 g of an epoxy resin. The epoxy equivalent was 173.0 g/eq, and the hydrolyzable chlorine was 490 ppm. The obtained resin is a biphenyldiol aralkyl type epoxy resin represented by the following formula (6). Further, in the formula (6), n means the number of repeating units.

[Example 1]

Adding a diglycidyl ether epoxy of 3,3',5,5'-tetramethylbiphenol in a separable flask equipped with a stirrer, a nitrogen gas inlet, a thermocouple, and a reflux port with a cooler 61.2 parts by weight of resin (manufactured by Mitsubishi Chemical Corporation, trade name; YX-4000, epoxy equivalent: 186, solid), 33.9 parts by weight of 4,4'-biphenol, 25 parts by weight of cyclohexanone, and heated to Dissolve at 145 ° C and stir for 1 hour. Then, 0.1 part by weight of tris-(2,6-dimethoxyphenyl)phosphine as a reaction catalyst was added, and the temperature was raised to 165 °C. As the reaction progressed, the viscosity increased, but stirring was continued in such a manner that cyclohexanone was appropriately added to become a fixed torque. The reaction is traced by gel permeation chromatography. When a specific weight average molecular weight is reached, cyclohexanone is added for cooling, and the reaction is stopped. should. The resulting solution was homogeneous and had a solid content of 29.7% by weight. The obtained phenoxy resin was a pale yellow liquid having an epoxy equivalent of 11,400 g/eq, a number average molecular weight of 15,300, and a weight average molecular weight of 40,600.

(Comparative Example 1)

Instead of 61.2 parts by weight of diglycidyl ether type epoxy resin of 3,3',5,5'-tetramethylbiphenol in Example 1, and 33.9 parts by weight of 4,4'-biphenol. Using bisphenol A type epoxy resin (manufactured by Nippon Steel & Sumitomo Chemical Co., Ltd., trade name; YD-8125, epoxy equivalent of 175, liquid) 65.8 parts by weight, and 4,4'-biphenol 24.2 Except for the above, the reaction was carried out in the same manner as in Example 1. As a result, a solid precipitated in the solution, and a phenoxy resin solution could not be obtained.

(Comparative Example 2)

Instead of 61.2 parts by weight of diglycidyl ether type epoxy resin of 3,3',5,5'-tetramethylbiphenol in Example 1, and 33.9 parts by weight of 4,4'-biphenol. Further, 62.0 parts by weight of a diglycidyl ether type epoxy resin of 2,7-dihydroxynaphthalene obtained in Synthesis Example 2-2 and 38.1 parts by weight of 4,4'-biphenol were used, and The reaction was carried out in the same manner as in Example 1. As a result, a solid precipitated in the solution, and a phenoxy resin solution could not be obtained.

[Example 2 to Example 12, and Comparative Example 3 to Comparative Example 6]

The epoxy resin composition, the raw material for producing the resin film, and the abbreviations thereof are as follows.

(A) Epoxy resin composition

(a) Epoxy resin

Epoxy resin (1): bisphenol epoxy resin (manufactured by Nippon Steel & Sumitomo Chemical Co., Ltd., trade name; YD-825GS, epoxy equivalent of 180, liquid)

Epoxy resin (2): phenyl aralkyl phenol type epoxy resin (manufactured by Nippon Kayaku Co., Ltd., trade name; NC-3000, epoxy equivalent 275, softening point 56 ° C)

Epoxy resin (3): Triphenylmethane type epoxy resin (manufactured by Nippon Kayaku Co., Ltd., trade name; EPPN-501H, epoxy equivalent of 170, semi-solid, softening point of 60 ° C)

Epoxy resin (4): 1,5-dihydroxynaphthalene type epoxy resin obtained in Synthesis Example 2-3 (softening point: 172 ° C)

Epoxy Resin (5): Biphenyldiphenol aralkyl type epoxy resin obtained in Synthesis Example 3-2 (softening point: 135 ° C)

(b) hardener

Hardener (1): 2-phenyl-4,5-dihydroxymethylimidazole (manufactured by Shikoku Chemical Industry Co., Ltd., trade name; Curezol 2PHz-PW)

(c) phenoxy resin

Phenoxy resin (1): biphenyldiol aralkyl phenoxy resin obtained in Example 1

Phenoxy resin (2): 1,6-dihydroxynaphthalene type phenoxy resin obtained in Synthesis Example 1-2

Phenoxy resin (3): bisphenol A type phenoxy resin (manufactured by Nippon Steel & Sumitomo Chemical Co., Ltd., trade name; YP-50)

Phenoxy resin (4): bisphenol AF type phenoxy resin (manufactured by Nippon Steel & Sumitomo Chemical Co., Ltd., trade name; ZX-1356-2)

(d) decane coupling agent

Decane coupling agent (1): manufactured by Chisso Co., Ltd., trade name; Sila Acc S-510

(B) spherical filler

Alumina powder (1): manufactured by Admatechs, trade name; AO-802, spherical, crystalline, maximum particle size; 10 μm, average particle size D ₅₀ ; 0.7 μm, Na ⁺ ; 1.3 ppm

Alumina powder (2): manufactured by Micron, trade name; AL10-75R, spherical, crystalline, maximum particle size; 75 μm, average particle diameter D ₅₀ ; 10 μm, Na ⁺ ; 3.9 ppm

Alumina powder (3): manufactured by Micron, trade name; AL35-75R, spherical, crystalline, maximum particle size; 75 μm, average particle size D ₅₀ ; 35 μm, Na ⁺ ; 1.8 ppm

(Production of varnish of epoxy resin composition)

The above raw materials were prepared in the proportions shown in Tables 1 to 3. First, only the phenoxy resin was stirred and dissolved in cyclohexanone by a vessel equipped with a stirrer. Next, an epoxy resin and a decane coupling agent were prepared in a cyclohexanone solution, and the mixture was heated to 80 °C. After cooling to room temperature, it was allowed to stand for 24 hours to confirm the presence or absence of crystal precipitation. Regarding the crystal-free precipitate, the curing agent and the alumina powder were blended, stirred and dispersed to prepare a varnish of the epoxy resin composition.

(Production of resin sheet and cured product)

The varnish obtained above was applied to a release-treated PET film (MRX-50 manufactured by Mitsubishi Chemicals Co., Ltd.) having a thickness of 50 μm so that the thickness of the dried resin layer was 200 μm, and dried at 130 ° C for 15 minutes. Thereby, a B-stage resin sheet is produced. The B-stage resin sheet was hardened at 180 ° C to obtain a cured product.

The results are shown in Tables 1 to 3. In addition, in the table, the blending amount of the epoxy resin, the hardener, the phenoxy resin, the alumina powder, the decane coupling agent, and the solvent (cyclohexanone) is shown by weight.

The embodiments of the present invention have been described in detail above with reference to the embodiments, but the present invention is not limited by the embodiments described above.

Claims (15)

An epoxy resin composition comprising: (a) component to (c) component: (a) an epoxy resin; (b) a hardener; and (c) a weight represented by the following formula (1) The amorphous phenoxy resin having an average molecular weight of 10,000 to 200,000, and the component (a) contains a liquid crystal original in a range of 5 to 100% by weight based on the total amount of the component (a). In the case of the crystalline epoxy resin, the component (c) is contained in an amount of from 5 parts by weight to 90 parts by weight based on 100 parts by weight of the total of the solid components in the component (a) and the component (c). ; In the formula (1), X represents a stretched biphenyl skeleton represented by the following formula (2) or an extended naphthyl skeleton represented by the following formula (3), and Y represents a stretch represented by the following formula (2). a biphenyl skeleton, Z represents a hydrogen atom or a glycidyl group, and n is a number representing a repeating unit] In the formula (2), R ₁ to R ₈ each independently represent a hydrogen atom or a linear or branched alkyl group 1 having 1 to 4 carbon atoms. The epoxy resin composition according to claim 1, wherein the liquid crystal primordial is a stretched biphenyl group. The epoxy resin composition according to claim 1, wherein the liquid crystal primordial is an anthranyl group. The epoxy resin composition according to claim 2, wherein the component (c) is an amorphous phenoxy resin, and the amorphous phenoxy resin has X and Y in the formula (1). The extended biphenyl skeleton represented by the above formula (2). The epoxy resin composition according to the above-mentioned formula (1), wherein X is at least 4 of R ₁ to R ₈ in the above formula (2) is an alkyl group having 4 or less carbon atoms. The rest is a biphenyl skeleton which is a hydrogen atom. The epoxy resin composition according to claim 5, wherein in the above formula (1), Y is an unsubstituted extended biphenyl having all of R ₁ to R ₈ in the above formula (2) being a hydrogen atom. Base skeleton. The epoxy resin composition according to claim 2, wherein in the above formula (1), X is a tetra group substituted with an alkyl group having 4 or less carbon atoms at the 3, 3' position and the 5, 5' position. The alkyl group is a biphenyl group and Y is an unsubstituted biphenyl group. The epoxy resin composition according to claim 3, wherein the component (c) is an amorphous phenoxy resin, and the amorphous phenoxy resin has the above formula (1), wherein X is the above formula (3) The naphthyl skeleton shown. The epoxy resin composition according to claim 8, wherein in the above formula (1), X is a stretching naphthyl skeleton having a single bond at the 1st and 6th positions, and Y is the above formula (2) The unsubstituted extended biphenyl skeleton in which all of R ₁ to R ₈ are a hydrogen atom. The epoxy resin composition according to any one of claims 1 to 9, further comprising the following component (d): (d) an inorganic filler. The epoxy resin composition according to any one of claims 1 to 10, further comprising the following component (e): (e) a solvent. A resin sheet obtained by forming an epoxy resin composition according to any one of claims 1 to 11 in a film form. A cured product obtained by hardening an epoxy resin composition according to any one of claims 1 to 11. A phenoxy resin comprising a tetramethyl-terminated phenyl group substituted with a methyl group at the 3,3'-position and the 5,5-position, and an unsubstituted extended biphenyl group, and having a weight average molecular weight of 10,000 In the range of ~200,000. The phenoxy resin as described in claim 14, wherein the tetramethyl-terminated phenyl group substituted with a methyl group at the 3,3'-position and the 5,5-position, and the unsubstituted extended biphenyl group The molar ratio of the base is approximately 1:1.