JP6083169B2 - Epoxy resin, curable resin composition, cured product thereof, and printed wiring board - Google Patents

Description

  The present invention has little change in heat resistance after the heat history of the cured product obtained, is excellent in low thermal expansion, and can be suitably used for printed wiring boards, semiconductor sealing materials, paints, casting applications, and the like, these The present invention relates to a cured product of a curable resin composition having the above performance and a printed wiring board.

Epoxy resins are used in adhesives, molding materials, paints, photoresist materials, color developing materials, etc., and are also used in semiconductor encapsulants and prints because they are excellent in the excellent heat resistance and moisture resistance of the resulting cured products. Widely used in electrical and electronic fields such as insulating materials for wiring boards.

  Among these various applications, in the field of printed wiring boards, with the trend toward miniaturization and high performance of electronic equipment, there is a tendency for high density due to narrowing of the wiring pitch of semiconductor devices. As a mounting method, a flip chip connection method in which a semiconductor device and a substrate are joined by solder balls is widely used. In this flip-chip connection method, a solder ball is placed between a wiring board and a semiconductor, and the whole is heated and melt bonded to form a so-called reflow semiconductor mounting method. Therefore, the wiring plate itself is exposed to a high heat environment during solder reflow. In some cases, due to thermal contraction of the wiring board, a large stress is generated in the solder balls connecting the wiring board and the semiconductor, resulting in poor connection of the wiring. Therefore, an insulating material used for a printed wiring board is required to have a low thermal expansion coefficient.

  In addition, in recent years, refractory solders that do not use lead have become mainstream due to laws and regulations for environmental problems, and the reflow temperature is high. Along with this, the connection failure due to the warp of the printed wiring board due to the heat resistance change of the insulating material during reflow is becoming serious. That is, a material with little change in physical properties during reflow is desired.

  In order to meet such requirements, for example, a thermosetting resin composition based on a naphthol novolac epoxy resin obtained by reacting naphthol, formaldehyde and epichlorohydrin solves technical problems such as low thermal expansion. It has been proposed (see Patent Document 1 below).

  However, the naphthol novolac type epoxy resin is required in recent years although the effect of improving the coefficient of thermal expansion of the resulting cured product is recognized due to the rigidity of the skeleton compared to the general phenol novolac type epoxy resin. The heat resistance of the cured product is greatly changed by the thermal history, and the change in heat resistance after reflow is large in printed circuit board applications, resulting in poor connection of the printed circuit board. It was easy to occur.

  As another naphthol novolak type epoxy resin, for example, a modified naphthol novolak type epoxy resin obtained by reacting naphthol, a bisphenol compound and epichlorohydrin is known (see Patent Document 2 below). Since such an epoxy resin also has a highly rigid skeleton, the effect of improving the low thermal expansion of the resulting cured product is recognized, but it does not fully satisfy the level required in recent years, and reflow Subsequent changes in heat resistance were also significant.

Japanese Examined Patent Publication No. 62-20206 JP-A-4-198314

  Accordingly, the problem to be solved by the present invention is that a curable resin composition exhibiting low thermal expansibility with little change in heat resistance after the heat history in the cured product, the cured product, and heat resistance after the heat history. It is an object of the present invention to provide a printed wiring board having little change and excellent in low thermal expansion, and an epoxy resin that provides these performances.

  As a result of intensive studies to solve the above problems, the present inventors have obtained an epoxy resin obtained by polyglycidyl etherification of a polycondensate of 4,4′-biphenol, β-naphthol compound, and formaldehyde, and has a specific structure. It is found that an epoxy resin containing a polyfunctional compound at a predetermined ratio exhibits excellent low thermal expansion in the cured product, and the reactivity of the epoxy resin itself is increased, so that a change in heat resistance after a thermal history is reduced. The present invention has been completed.

That is, the present invention is an epoxy resin obtained by polyglycidyl etherification of a polycondensate of 4,4′-biphenol, β-naphthol compound, and formaldehyde, and the following structural formula (1) is contained in the epoxy resin.

（式中、Ｒ^１及びＲ^２は、それぞれ独立して水素原子、炭素原子数１〜４のアルキル基、炭素原子数１〜４のアルコキシ基を示し、Ｇはグリシジル基を表す。また、ｎは１又は２、ｍは０〜２の整数である。）
で表される多官能化合物（ｘ）を含有し、該多官能化合物（ｘ）の含有率がＧＰＣ測定における面積比率で３０％以上であることを特徴とするエポキシ樹脂に関する。

(In the formula, R ¹ and R ² each independently represent a hydrogen atom, an alkyl group having 1 to 4 carbon atoms, or an alkoxy group having 1 to 4 carbon atoms, and G represents a glycidyl group. Is 1 or 2, m is an integer of 0-2.)
It is related with the epoxy resin characterized by containing the polyfunctional compound (x) represented by these, and the content rate of this polyfunctional compound (x) is 30% or more by the area ratio in GPC measurement.

  The present invention further relates to a curable resin composition containing the above-described epoxy resin and a curing agent as essential components.

  The present invention further relates to a cured product obtained by curing reaction of the curable resin composition.

  The present invention further provides a printed wiring board obtained by impregnating a reinforcing base material with a resin composition obtained by further blending an organic solvent with the curable resin composition, and then laminating the copper foil and heat-pressing it. About.

  According to the present invention, there is little change in heat resistance after thermal history in the cured product, and the curable resin composition that exhibits low thermal expansion, the cured product, low thermal expansion property after little heat resistance change after thermal history. Printed circuit boards excellent in the above, and epoxy resins that give these performances.

1 is a GPC chart of the biphenol-naphthol resin (a-1) obtained in Example 1. FIG. FIG. 2 is a GPC chart of the epoxy resin (A-1) obtained in Example 1. FIG. 3 is a GPC chart of the epoxy resin (A-2) obtained in Example 2. 4 is a C ¹³ NMR chart of the epoxy resin (A-2) obtained in Example 2. FIG. FIG. 5 is an MS spectrum of the epoxy resin (A-2) obtained in Example 2. 6 is a GPC chart of the epoxy resin (A-3) obtained in Example 3. FIG. FIG. 7 is a GPC chart of the epoxy resin (A′-1) obtained in Comparative Synthesis Example 1. FIG. 8 is a GPC chart of the phenol resin (a′-2) obtained in Comparative Synthesis Example 2.

Hereinafter, the present invention will be described in detail.
The epoxy resin of the present invention is an epoxy resin obtained by polyglycidyl etherification of a polycondensate of 4,4′-biphenol, a β-naphthol compound, and formaldehyde, and the following structural formula (1) is contained in the epoxy resin.

（式中、Ｒ^１及びＲ^２は、それぞれ独立して水素原子、炭素原子数１〜４のアルキル基、炭素原子数１〜４のアルコキシ基を示し、Ｇはグリシジル基を表す。また、ｎは１又は２、ｍは０〜２の整数である。）
で表される多官能化合物（ｘ）を含有し、該多官能化合物（ｘ）の含有率がＧＰＣ測定における面積比率で３０％以上であることを特徴とするエポキシ樹脂としている。

(In the formula, R ¹ and R ² each independently represent a hydrogen atom, an alkyl group having 1 to 4 carbon atoms, or an alkoxy group having 1 to 4 carbon atoms, and G represents a glycidyl group. Is 1 or 2, m is an integer of 0-2.)
The polyfunctional compound (x) represented by this is contained, and the content rate of this polyfunctional compound (x) is 30% or more by the area ratio in GPC measurement, It is set as the epoxy resin characterized by the above-mentioned.

  That is, the epoxy resin of the present invention is a polyglycidyl ether of a polycondensate using 4,4′-biphenol, β-naphthol compound, and formaldehyde as raw materials, and is a mixture containing various resin structures. Among them, the polyfunctional compound (x) is contained in a predetermined amount. The oligomer compound such as the polyfunctional compound (x) has higher molecular orientation than a long chain epoxy resin such as a general novolak type epoxy resin, and has excellent low thermal expansion in the cured product. Sex can be expressed. Further, the epoxy resin of the present invention containing an oligomer compound having a controlled structure such as the polyfunctional compound (x) at a high concentration of 30% or more has high reactivity as compared with a long-chain epoxy resin. Since the cured product is more densely cross-linked, it becomes a material with little change in heat resistance after heat history and little change in physical properties after reflow in printed wiring board applications.

  Here, as described above, the content ratio of the polyfunctional compound (x) is 30% or more in terms of the area ratio in the GPC measurement, and when it is less than 30%, the thermal expansion coefficient of the cured product becomes high. Furthermore, it is more preferably 40% or more because a cured product having excellent low thermal expansibility and small heat resistance change after heat history can be obtained.

  In the said General formula (1), n is 1 or 2, and m is an integer of 0-2. That is, the polyfunctional compound (x) represented by the general formula (1) has 3 to 6 glycidyl groups in the molecular structure. Among them, a hexafunctional compound in which n and m are both 2 because it is a material having excellent curability, less heat-resistant change after heat history in a cured product, and less property change after reflow in printed wiring board applications ( x6) is preferably contained.

  At this time, the content of the hexafunctional compound (x6) is preferably 5% or more in terms of an area ratio in GPC measurement because the orientation is excellent and the thermal expansion coefficient of the cured product is low. Furthermore, since the orientation of the epoxy resin is high and the effect of being excellent in low thermal expansion can be obtained more remarkably, the content of the hexafunctional body (x6) in the epoxy resin is more preferably 15% or more.

  Such hexafunctional (x6) specifically includes the following structural formulas (1-1) to (1-6).

で表される化合物が挙げられる。これらのなかでも特に前記構造式１−１で表されるもの、即ち、前記構造式（１）におけるＲ^１及びＲ^２が、全て水素原子であるものが、硬化物における熱膨張係数が小さくなる点から好ましい。

The compound represented by these is mentioned. Among these, particularly those represented by the structural formula 1-1, that is, those in which R ¹ and R ² in the structural formula (1) are all hydrogen atoms, the thermal expansion coefficient of the cured product is small. It is preferable from the point.

  The epoxy resin of the present invention further comprises the following structural formula (2) in addition to the polyfunctional compound (x).

（式中、Ｇはグリシジル基を表す。）
で表される、前記２官能体（ｙ）を含有することが、硬化物における低線膨張性が一層良好なものとなる点から好ましい。

(In the formula, G represents a glycidyl group.)
It is preferable from the point that the low linear expansion property in hardened | cured material becomes a better thing to contain the said bifunctional body (y) represented by these.

  At this time, the content of the polyfunctional compound (x) in the epoxy resin and the content of the bifunctional compound (y) are excellent in solvent solubility and low linear expansion, and further after heat history in the cured product. Since the material has little change in heat resistance and little change in physical properties after reflow in printed wiring board applications, the content ratio of the polyfunctional compound (x) is in the range of 30 to 95% in terms of area ratio in GPC measurement. In addition, the content of the bifunctional compound (y) is preferably in the range of 1 to 25%.

In the present invention, the polyfunctional compound (x), the hexafunctional (x6), and the content of the bifunctional (y) in the epoxy resin are calculated by GPC measurement under the following conditions. It is the ratio of the peak area of each structure to the total peak area of the epoxy resin.
<GPC measurement conditions>
Measuring device: “HLC-8220 GPC” manufactured by Tosoh Corporation
Column: Guard column “HXL-L” manufactured by Tosoh Corporation
+ "TSK-GEL G2000HXL" manufactured by Tosoh Corporation
+ "TSK-GEL G2000HXL" manufactured by Tosoh Corporation
+ Tosoh Corporation “TSK-GEL G3000HXL”
+ Tosoh Corporation “TSK-GEL G4000HXL”
Detector: RI (differential refractometer)
Data processing: “GPC-8020 Model II version 4.10” manufactured by Tosoh Corporation
Measurement conditions: Column temperature 40 ° C
Developing solvent Tetrahydrofuran
Flow rate: 1.0 ml / min Standard: The following monodisperse polystyrene having a known molecular weight was used in accordance with the measurement manual of “GPC-8020 Model II version 4.10”.
(Polystyrene used)
“A-500” manufactured by Tosoh Corporation
"A-1000" manufactured by Tosoh Corporation
"A-2500" manufactured by Tosoh Corporation
"A-5000" manufactured by Tosoh Corporation
“F-1” manufactured by Tosoh Corporation
"F-2" manufactured by Tosoh Corporation
“F-4” manufactured by Tosoh Corporation
“F-10” manufactured by Tosoh Corporation
“F-20” manufactured by Tosoh Corporation
“F-40” manufactured by Tosoh Corporation
“F-80” manufactured by Tosoh Corporation
“F-128” manufactured by Tosoh Corporation
Sample: A 1.0 mass% tetrahydrofuran solution filtered in terms of resin solids and filtered through a microfilter (50 μl).

  In addition to the polyfunctional compound (x) and the bifunctional compound (y) described above, the epoxy resin of the present invention may contain other high molecular weight compounds (z) that are generated when the epihalohydrin is reacted. .

  The epoxy resin of the present invention described in detail above preferably has a softening point in the range of 80 to 140 ° C. from the viewpoint of excellent solvent solubility of the epoxy resin itself. Therefore, the molecular weight of the other high molecular weight substance (z) And the softening point of the epoxy resin may be appropriately adjusted so that it falls within the above range. The softening point is particularly preferably in the range of 85 to 135 ° C. from the viewpoint that the low thermal expansion property and the solvent solubility can be highly combined.

  Moreover, it is preferable that the epoxy equivalent of the epoxy resin of the present invention is in the range of 170 to 300 g / eq from the viewpoint of good low thermal expansion of the cured product, and particularly in the range of 190 to 260 g / eq. Is preferred.

The epoxy resin of the present invention described in detail above can be produced by, for example, the following method 1 or method 2.
Method 1: A β-naphthol compound and formaldehyde are reacted in the presence of an organic solvent and an alkali catalyst, and then 4,4′-biphenol is added and reacted in the presence of formaldehyde to obtain a biphenol-naphthol resin (step) 1) Next, the resulting biphenol-naphthol resin is reacted with epihalohydrin (step 2) to obtain the desired epoxy resin.
Method 2: Biphenol-naphthol resin is obtained by reacting 4,4′-biphenol, β-naphthol compound, and formaldehyde in the presence of an organic solvent and an alkali catalyst (step 1), and then the resulting biphenol-naphthol resin is obtained. A method of obtaining a target epoxy resin by reacting with epihalohydrin (step 2).

  In the present invention, the polyfunctional compound (x) and the 2 are used by using an alkali catalyst as a reaction catalyst in Step 1 of the method 1 or 2 and using an organic solvent in a small amount relative to the raw material components. The proportion of the monomer (y) in the epoxy resin can be adjusted to a predetermined range.

  Examples of the alkali catalyst used herein include alkali metal hydroxides such as sodium hydroxide and potassium hydroxide, inorganic alkalis such as metal sodium, metal lithium, sodium hydride, sodium carbonate, and potassium carbonate. The amount used is preferably in the range of 0.01 to 2.0 times the molar amount of the total number of phenolic hydroxyl groups of 4,4′-biphenol and β-naphthol compounds as raw material components. .

  Examples of the organic solvent include methyl cellosolve, isopropyl alcohol, ethyl cellosolve, toluene, xylene, and methyl isobutyl ketone. Among these, isopropyl alcohol is preferable because the formation of the polyfunctional compound (x) is promoted. The amount of the organic solvent used in the present invention is in the range of 5 to 70 parts by mass per 100 parts by mass of the total mass of 4,4′-biphenol and β-naphthol compounds as raw material components. x) and the dimer (y) in the epoxy resin are preferably present from the point of being easily adjusted to a predetermined range.

  In the present invention, 4,4'-biphenol is used as an essential raw material component. Among the biphenols, by using a 4,4'-type, the hexafunctional product (x6) can be obtained efficiently, and the low thermal expansion property of the resulting cured epoxy resin is improved.

  The β-naphthol compound which is another essential component of the present invention has β-naphthol and an alkyl group such as methyl group, ethyl group, propyl group and t-butyl group, alkoxy group such as methoxy group and ethoxy group. Examples include compounds substituted by nuclei. Among these, β-naphthol having no substituent is preferable from the viewpoint that the heat resistance change after the heat history in the cured epoxy resin finally obtained is reduced.

  On the other hand, the formaldehyde used here may be a formalin solution in an aqueous solution state or paraformaldehyde in a solid state.

  The use ratio of 4,4′-biphenol and β-naphthol compound in Step 1 of Method 1 or Method 2 is such that the molar ratio (4,4′-biphenol / β-naphthol compound) is [1 / 0.5. It is preferable that the ratio of each component in the finally obtained epoxy resin is easily adjusted to be in the range of [1/8] to [1/8].

  The reaction charge ratio of formaldehyde is a ratio of 0.6 to 2.0 times the amount of formaldehyde on a molar basis with respect to the total number of moles of 4,4′-biphenol and β-naphthol compound, From the viewpoint of excellent low thermal expansibility, the ratio is preferably 0.6 to 1.5 times.

  In Step 1 of Method 1, a reaction vessel is charged with a predetermined amount of β-naphthol compound, formaldehyde, an organic solvent, and an alkali catalyst and reacted at 40 to 100 ° C. After the reaction is completed, 4,4′-biphenol. (If necessary, formaldehyde is further added, and the reaction is carried out at a temperature of 40 to 100 ° C. to obtain the desired polycondensate.

  After completion of the reaction in Step 1, neutralization or water washing is performed until the pH value of the reaction mixture becomes 4 to 7 after the reaction is completed. The neutralization treatment and the water washing treatment may be performed according to conventional methods. For example, acidic substances such as acetic acid, phosphoric acid, and sodium phosphate can be used as the neutralizing agent. After neutralization or water washing treatment, the organic solvent is distilled off under reduced pressure heating to obtain the desired polycondensate.

  In Step 1 of Method 2, the reaction vessel is charged with a predetermined amount of β-naphthol compound, 4,4′-biphenol, formaldehyde, an organic solvent, and an alkali catalyst, and reacted at 40 to 100 ° C. for the purpose. A polycondensate can be obtained.

  After completion of the reaction in Step 1, neutralization or water washing is performed until the pH value of the reaction mixture becomes 4 to 7 after the reaction is completed. The neutralization treatment and the water washing treatment may be performed according to conventional methods. For example, acidic substances such as acetic acid, phosphoric acid, and sodium phosphate can be used as the neutralizing agent. After neutralization or water washing treatment, the organic solvent is distilled off under reduced pressure heating to obtain the desired polycondensate.

  Next, Step 2 of Method 1 or Method 2 is a step of producing the desired epoxy resin by reacting the polycondensate obtained in Step 1 with epihalohydrin. Specifically, in the step 2, epihalohydrin is added in a ratio of 2 to 10 times (molar basis) with respect to the number of moles of the phenolic hydroxyl group in the polycondensate, and further the mole of the phenolic hydroxyl group. A method of reacting at a temperature of 20 to 120 ° C. for 0.5 to 10 hours while adding or gradually adding 0.9 to 2.0 times (molar basis) of the basic catalyst to the number is mentioned. The basic catalyst may be solid or an aqueous solution thereof. When an aqueous solution is used, it is continuously added and water and epihalohydrins are continuously distilled from the reaction mixture under reduced pressure or normal pressure. Alternatively, the solution may be separated and further separated to remove water and the epihalohydrin is continuously returned to the reaction mixture.

  In the first batch of epoxy resin production, all of the epihalohydrins used for preparation are new in industrial production, but the subsequent batches are consumed by the reaction with epihalohydrins recovered from the crude reaction product. It is preferable to use in combination with new epihalohydrins corresponding to the amount disappeared. At this time, the epihalohydrin used is not particularly limited, and examples thereof include epichlorohydrin, epibromohydrin, β-methylepichlorohydrin, and the like. Of these, epichlorohydrin is preferred because it is easily available industrially.

  Specific examples of the basic catalyst include alkaline earth metal hydroxides, alkali metal carbonates, and alkali metal hydroxides. In particular, alkali metal hydroxides are preferable from the viewpoint of excellent catalytic activity of the epoxy resin synthesis reaction, and examples thereof include sodium hydroxide and potassium hydroxide. In use, these basic catalysts may be used in the form of an aqueous solution of about 10 to 55% by mass, or in the form of a solid. Moreover, the reaction rate in the synthesis | combination of an epoxy resin can be raised by using an organic solvent together. Examples of such organic solvents include, but are not limited to, ketones such as acetone and methyl ethyl ketone, alcohol compounds such as methanol, ethanol, 1-propyl alcohol, isopropyl alcohol, 1-butanol, secondary butanol, and tertiary butanol, methyl Examples thereof include cellosolves such as cellosolve and ethyl cellosolve, ether compounds such as tetrahydrofuran, 1,4-dioxane, 1,3-dioxane and diethoxyethane, and aprotic polar solvents such as acetonitrile, dimethyl sulfoxide and dimethylformamide. These organic solvents may be used alone or in combination of two or more kinds in order to adjust the polarity.

  After the reaction product of the epoxidation reaction is washed with water, unreacted epihalohydrin and the organic solvent to be used in combination are distilled off by distillation under heating and reduced pressure. Further, in order to obtain an epoxy resin with less hydrolyzable halogen, the obtained epoxy resin is again dissolved in an organic solvent such as toluene, methyl isobutyl ketone, methyl ethyl ketone, and alkali metal hydroxide such as sodium hydroxide or potassium hydroxide. Further reaction can be carried out by adding an aqueous solution of the product. At this time, a phase transfer catalyst such as a quaternary ammonium salt or crown ether may be present for the purpose of improving the reaction rate. When the phase transfer catalyst is used, the amount used is preferably 0.1 to 3.0 parts by mass with respect to 100 parts by mass of the epoxy resin used. After completion of the reaction, the produced salt is removed by filtration, washing with water, etc., and further, the target epoxy resin of the present invention can be obtained by distilling off a solvent such as toluene and methyl isobutyl ketone under heating and reduced pressure.

  Next, the curable resin composition of the present invention comprises the epoxy resin and the curing agent detailed above as essential components.

Examples of the curing agent used here include amine compounds, amide compounds, acid anhydride compounds, phenol compounds, and the like. Specifically, examples of the amine compound include diaminodiphenylmethane, diethylenetriamine, triethylenetetramine, diaminodiphenylsulfone, isophoronediamine, imidazole, BF ₃ -amine complex, and guanidine derivative. Examples of the amide compound include dicyandiamide. And polyamide resins synthesized from dimer of linolenic acid and ethylenediamine. Examples of acid anhydride compounds include phthalic anhydride, trimellitic anhydride, pyromellitic anhydride, maleic anhydride, and tetrahydrophthalic anhydride. Acid, methyltetrahydrophthalic anhydride, methyl nadic anhydride, hexahydrophthalic anhydride, methylhexahydrophthalic anhydride, etc., and phenolic compounds include phenol novolac resin, cresol novolac resin Aromatic hydrocarbon formaldehyde resin modified phenolic resin, dicyclopentadiene phenol addition type resin, phenol aralkyl resin (Zylok resin), polyhydric phenol novolak resin synthesized from formaldehyde and polyhydroxy compound represented by resorcin novolac resin, naphthol Aralkyl resin, trimethylol methane resin, tetraphenylol ethane resin, naphthol novolac resin, naphthol-phenol co-condensed novolac resin, naphthol-cresol co-condensed novolac resin, biphenyl-modified phenol resin (polyvalent polyphenol with bismethylene group linked to phenol nucleus) Phenolic compounds), biphenyl-modified naphthol resins (polyvalent naphthol compounds in which phenol nuclei are linked by bismethylene groups), aminotriazine-modified phenols Resin (polyhydric phenol compound in which phenol nucleus is linked with melamine, benzoguanamine, etc.) or alkoxy group-containing aromatic ring modified novolak resin (polyhydric phenol compound in which phenol nucleus and alkoxy group-containing aromatic ring are linked with formaldehyde) Examples thereof include polyhydric phenol compounds, polyphenylene ether resins, cyanate esters of the various phenol compounds, and active esters of the various phenol compounds.

  Among these, those containing a large amount of an aromatic skeleton in the molecular structure are preferred from the viewpoint of low thermal expansion, and specifically, phenol novolac resins, cresol novolac resins, aromatic hydrocarbon formaldehyde resin-modified phenol resins, phenol aralkyls. Resin, resorcinol novolak resin, naphthol aralkyl resin, naphthol novolak resin, naphthol-phenol co-condensed novolak resin, naphthol-cresol co-condensed novolak resin, biphenyl-modified phenol resin, biphenyl-modified naphthol resin, aminotriazine-modified phenol resin, alkoxy group-containing aromatic A ring-modified novolak resin (a polyhydric phenol compound in which a phenol nucleus and an alkoxy group-containing aromatic ring are linked with formaldehyde) is preferable because of its low thermal expansion.

  The blending amount of the epoxy resin and the curing agent in the curable resin composition of the present invention is not particularly limited, but a total of 1 equivalent of epoxy groups of the epoxy resin is obtained from the point that the obtained cured product property is good. In contrast, the amount by which the active group in the curing agent is 0.7 to 1.5 equivalents is preferable.

  Moreover, a hardening accelerator can also be suitably used together with the curable resin composition of this invention as needed. Various curing accelerators can be used, and examples thereof include phosphorus compounds, tertiary amines, imidazoles, organic acid metal salts, Lewis acids, and amine complex salts. In particular, when used as a semiconductor encapsulating material, it is excellent in curability, heat resistance, electrical characteristics, moisture resistance reliability, etc., so that triphenylphosphine is used for phosphorus compounds and 1,8-diazabicyclo is used for tertiary amines. -[5.4.0] -undecene (DBU) is preferred.

  In the curable resin composition of the present invention, the epoxy resin of the present invention described above may be used alone as an epoxy resin component, but other epoxy resins may be used within a range not impairing the effects of the present invention. . Specifically, the epoxy resin of the present invention described above can be used in combination with another epoxy resin within a range of 30% by mass or more, preferably 40% by mass or more with respect to the total mass of the epoxy resin component.

  Here, as other epoxy resins that can be used in combination with the epoxy resin, various epoxy resins can be used. For example, bisphenol A type epoxy resin, bisphenol F type epoxy resin, biphenyl type epoxy resin, tetramethylbiphenyl type Epoxy resin, phenol novolac type epoxy resin, cresol novolac type epoxy resin, bisphenol A novolac type epoxy resin, triphenylmethane type epoxy resin, tetraphenylethane type epoxy resin, dicyclopentadiene-phenol addition reaction type epoxy resin, phenol aralkyl type Epoxy resin, naphthol novolak epoxy resin, naphthol aralkyl epoxy resin, naphthol-phenol co-condensed novolac epoxy resin, naphthol-cresol co-condensate Novolac type epoxy resin, aromatic hydrocarbon formaldehyde resin-modified phenol resin type epoxy resin, a biphenyl novolak type epoxy resins. Among these, phenol aralkyl type epoxy resins, biphenyl novolak type epoxy resins, naphthol novolak type epoxy resins containing a naphthalene skeleton, naphthol aralkyl type epoxy resins, naphthol-phenol co-condensed novolac type epoxy resins, naphthol-cresol co-condensed novolacs. Type epoxy resin, crystalline biphenyl type epoxy resin, tetramethyl biphenyl type epoxy resin, xanthene type epoxy resin, alkoxy group-containing aromatic ring-modified novolak type epoxy resin (formaldehyde glycidyl group-containing aromatic ring and alkoxy group-containing aromatic ring Are particularly preferable in that a cured product having excellent heat resistance can be obtained.

  As described above, the curable resin composition of the present invention described in detail above is characterized by exhibiting excellent solvent solubility. Therefore, the curable resin composition preferably contains an organic solvent in addition to the above components. Examples of the organic solvent that can be used here include methyl ethyl ketone, acetone, dimethylformamide, methyl isobutyl ketone, methoxypropanol, cyclohexanone, methyl cellosolve, ethyl diglycol acetate, and propylene glycol monomethyl ether acetate. The amount used can be appropriately selected depending on the application. For example, in printed wiring board applications, it is preferable to use a polar solvent having a boiling point of 160 ° C. or lower, such as methyl ethyl ketone, acetone, dimethylformamide, and the non-volatile content of 40 to 80% by mass. It is preferable to use in the ratio which becomes. On the other hand, in build-up adhesive film applications, as organic solvents, for example, ketones such as acetone, methyl ethyl ketone, cyclohexanone, acetates such as ethyl acetate, butyl acetate, cellosolve acetate, propylene glycol monomethyl ether acetate, carbitol acetate, It is preferable to use carbitols such as cellosolve and butyl carbitol, aromatic hydrocarbons such as toluene and xylene, dimethylformamide, dimethylacetamide, N-methylpyrrolidone and the like, and the nonvolatile content is 30 to 60% by mass. It is preferable to use in proportions.

  The curable resin composition is a non-halogen flame retardant that substantially does not contain a halogen atom, for example, in the field of printed wiring boards, in order to exhibit flame retardancy, as long as reliability is not lowered. You may mix | blend.

  Examples of the non-halogen flame retardants include phosphorus flame retardants, nitrogen flame retardants, silicone flame retardants, inorganic flame retardants, and organic metal salt flame retardants. The flame retardants may be used alone or in combination, and a plurality of flame retardants of the same system may be used, or different types of flame retardants may be used in combination.

  As the phosphorus flame retardant, either inorganic or organic can be used. Examples of the inorganic compounds include red phosphorus, monoammonium phosphate, diammonium phosphate, triammonium phosphate, ammonium phosphates such as ammonium polyphosphate, and inorganic nitrogen-containing phosphorus compounds such as phosphate amide. .

  The red phosphorus is preferably subjected to a surface treatment for the purpose of preventing hydrolysis and the like. Examples of the surface treatment method include (i) magnesium hydroxide, aluminum hydroxide, zinc hydroxide, water A method of coating with an inorganic compound such as titanium oxide, bismuth oxide, bismuth hydroxide, bismuth nitrate or a mixture thereof; (ii) an inorganic compound such as magnesium hydroxide, aluminum hydroxide, zinc hydroxide, titanium hydroxide; and A method of coating with a mixture of a thermosetting resin such as a phenol resin, (iii) thermosetting of a phenol resin or the like on a coating of an inorganic compound such as magnesium hydroxide, aluminum hydroxide, zinc hydroxide, or titanium hydroxide For example, a method of double coating with a resin may be used.

  Examples of the organic phosphorus compound include, for example, general-purpose organic phosphorus compounds such as phosphate ester compounds, phosphonic acid compounds, phosphinic acid compounds, phosphine oxide compounds, phosphorane compounds, organic nitrogen-containing phosphorus compounds, and 9,10- Dihydro-9-oxa-10-phosphaphenanthrene = 10-oxide, 10- (2,5-dihydrooxyphenyl) -10H-9-oxa-10-phosphaphenanthrene = 10-oxide, 10- (2,7 -Dihydrooxynaphthyl) -10H-9-oxa-10-phosphaphenanthrene = 10-oxide and other cyclic organic phosphorus compounds, and derivatives obtained by reacting them with compounds such as epoxy resins and phenol resins.

  The blending amount thereof is appropriately selected depending on the type of the phosphorus-based flame retardant, the other components of the curable resin composition, and the desired degree of flame retardancy. In 100 parts by mass of curable resin composition containing all of halogen-based flame retardant and other fillers and additives, 0.1 to 2.0 parts by mass of red phosphorus is used as a non-halogen flame retardant. It is preferable to mix in the range, and when using an organophosphorus compound, it is preferably mixed in the range of 0.1 to 10.0 parts by mass, particularly in the range of 0.5 to 6.0 parts by mass. It is preferable to do.

  In addition, when using the phosphorous flame retardant, the phosphorous flame retardant may be used in combination with hydrotalcite, magnesium hydroxide, boric compound, zirconium oxide, black dye, calcium carbonate, zeolite, zinc molybdate, activated carbon, etc. Good.

  Examples of the nitrogen-based flame retardant include triazine compounds, cyanuric acid compounds, isocyanuric acid compounds, phenothiazines, and the like, and triazine compounds, cyanuric acid compounds, and isocyanuric acid compounds are preferable.

  Examples of the triazine compound include melamine, acetoguanamine, benzoguanamine, melon, melam, succinoguanamine, ethylene dimelamine, melamine polyphosphate, triguanamine, and the like, for example, (i) guanylmelamine sulfate, melem sulfate, sulfate (Iii) co-condensates of phenols such as phenol, cresol, xylenol, butylphenol and nonylphenol with melamines such as melamine, benzoguanamine, acetoguanamine and formguanamine and formaldehyde, (iii) (Ii) a mixture of a co-condensate of (ii) and a phenolic resin such as a phenol formaldehyde condensate, (iv) those obtained by further modifying (ii) and (iii) with paulownia oil, isomerized linseed oil, etc. It is.

  Specific examples of the cyanuric acid compound include cyanuric acid and cyanuric acid melamine.

  The compounding amount of the nitrogen-based flame retardant is appropriately selected according to the type of the nitrogen-based flame retardant, the other components of the curable resin composition, and the desired degree of flame retardancy. For example, an epoxy resin, It is preferable to mix in the range of 0.05 to 10 parts by mass in 100 parts by mass of the curable resin composition containing all of the curing agent, non-halogen flame retardant and other fillers and additives. It is preferable to mix | blend in the range of 1-5 mass parts.

  Moreover, when using the said nitrogen-type flame retardant, you may use together a metal hydroxide, a molybdenum compound, etc.

  The silicone flame retardant is not particularly limited as long as it is an organic compound containing a silicon atom, and examples thereof include silicone oil, silicone rubber, and silicone resin.

  The amount of the silicone-based flame retardant is appropriately selected depending on the type of the silicone-based flame retardant, the other components of the curable resin composition, and the desired degree of flame retardancy. For example, an epoxy resin, It is preferable to mix in the range of 0.05 to 20 parts by mass in 100 parts by mass of the curable resin composition containing all of the curing agent, non-halogen flame retardant and other fillers and additives. Moreover, when using the said silicone type flame retardant, you may use a molybdenum compound, an alumina, etc. together.

  Examples of the inorganic flame retardant include metal hydroxide, metal oxide, metal carbonate compound, metal powder, boron compound, and low melting point glass.

  Specific examples of the metal hydroxide include aluminum hydroxide, magnesium hydroxide, dolomite, hydrotalcite, calcium hydroxide, barium hydroxide, zirconium hydroxide and the like.

  Specific examples of the metal oxide include, for example, zinc molybdate, molybdenum trioxide, zinc stannate, tin oxide, aluminum oxide, iron oxide, titanium oxide, manganese oxide, zirconium oxide, zinc oxide, molybdenum oxide, and cobalt oxide. Bismuth oxide, chromium oxide, nickel oxide, copper oxide, tungsten oxide and the like.

  Specific examples of the metal carbonate compound include zinc carbonate, magnesium carbonate, calcium carbonate, barium carbonate, basic magnesium carbonate, aluminum carbonate, iron carbonate, cobalt carbonate, and titanium carbonate.

  Specific examples of the metal powder include aluminum, iron, titanium, manganese, zinc, molybdenum, cobalt, bismuth, chromium, nickel, copper, tungsten, and tin.

  Specific examples of the boron compound include zinc borate, zinc metaborate, barium metaborate, boric acid, and borax.

Specific examples of the low-melting-point glass include, for example, Ceeley (Bokusui Brown), hydrated glass SiO ₂ —MgO—H ₂ O, PbO—B ₂ O ₃ system, ZnO—P ₂ O ₅ —MgO system, P ₂ O ₅ —B ₂ O ₃ —PbO—MgO, P—Sn—O—F, PbO—V ₂ O ₅ —TeO ₂ , Al ₂ O ₃ —H ₂ O, lead borosilicate, etc. The glassy compound can be mentioned.

  The amount of the inorganic flame retardant is appropriately selected depending on the type of the inorganic flame retardant, the other components of the curable resin composition, and the desired degree of flame retardancy. For example, an epoxy resin, It is preferable to mix in the range of 0.05 to 20 parts by mass in 100 parts by mass of the curable resin composition containing all of the curing agent, non-halogen flame retardant and other fillers and additives. It is preferable to mix | blend in 5-15 mass parts.

  Examples of the organic metal salt flame retardant include ferrocene, acetylacetonate metal complex, organic metal carbonyl compound, organic cobalt salt compound, organic sulfonic acid metal salt, metal atom and aromatic compound or heterocyclic compound or an ionic bond or Examples thereof include a coordinated compound.

  The amount of the organic metal salt flame retardant is appropriately selected depending on the type of the organic metal salt flame retardant, the other components of the curable resin composition, and the desired degree of flame retardancy. In 100 parts by mass of the curable resin composition in which all of epoxy resin, curing agent, non-halogen flame retardant and other fillers and additives are blended, it is preferably blended in the range of 0.005 to 10 parts by mass. .

  An inorganic filler can be mix | blended with the curable resin composition of this invention as needed. Examples of the inorganic filler include fused silica, crystalline silica, alumina, silicon nitride, and aluminum hydroxide. When particularly increasing the blending amount of the inorganic filler, it is preferable to use fused silica. The fused silica can be used in either a crushed shape or a spherical shape. However, in order to increase the blending amount of the fused silica and suppress an increase in the melt viscosity of the molding material, it is preferable to mainly use a spherical shape. In order to further increase the blending amount of the spherical silica, it is preferable to appropriately adjust the particle size distribution of the spherical silica. The filling rate is preferably higher in consideration of flame retardancy, and particularly preferably 20% by mass or more with respect to the total amount of the curable resin composition. Moreover, when using for uses, such as an electrically conductive paste, electroconductive fillers, such as silver powder and copper powder, can be used.

  Various compounding agents, such as a silane coupling agent, a mold release agent, a pigment, an emulsifier, can be added to the curable resin composition of this invention as needed.

  The curable resin composition of the present invention can be obtained by uniformly mixing the above-described components. The curable resin composition of the present invention in which the epoxy resin of the present invention, a curing agent, and further, if necessary, a curing accelerator are blended can be easily made into a cured product by a method similar to a conventionally known method. Examples of the cured product include molded cured products such as laminates, cast products, adhesive layers, coating films, and films.

  Applications for which the curable resin composition of the present invention is used include printed wiring board materials, resin casting materials, adhesives, interlayer insulation materials for build-up substrates, and adhesive films for build-ups. Among these various applications, in printed circuit boards, insulating materials for electronic circuit boards, and adhesive films for build-up, passive parts such as capacitors and active parts such as IC chips are embedded in so-called electronic parts. It can be used as an insulating material for a substrate. Among these, it is preferable to use for the printed wiring board material and the adhesive film for buildup from the characteristics, such as a small heat resistance change after heat history, low thermal expansibility, and solvent solubility.

  Here, in order to produce a printed circuit board from the curable resin composition of the present invention, the varnish-like curable resin composition containing the organic solvent is impregnated into a reinforcing base material, and a copper foil is overlaid and thermocompression bonded. A method is mentioned. Examples of the reinforcing substrate that can be used here include paper, glass cloth, glass nonwoven fabric, aramid paper, aramid cloth, glass mat, and glass roving cloth. If this method is described in further detail, first, the varnish-like curable resin composition is heated at a heating temperature corresponding to the solvent type used, preferably 50 to 170 ° C., thereby being a prepreg which is a cured product. Get. The mass ratio of the resin composition and the reinforcing substrate used at this time is not particularly limited, but it is usually preferable that the resin content in the prepreg is 20 to 60% by mass. Next, the prepreg obtained as described above is laminated by a conventional method, and a copper foil is appropriately stacked, and then subjected to thermocompression bonding at a pressure of 1 to 10 MPa at 170 to 250 ° C. for 10 minutes to 3 hours, A desired printed circuit board can be obtained.

  When the curable resin composition of the present invention is used as a resist ink, for example, a cationic polymerization catalyst is used as a curing agent for the curable resin composition, and a pigment, talc, and filler are further added to form a resist ink composition. After making it into a product, after applying on a printed board by a screen printing method, a method of forming a resist ink cured product can be mentioned.

  When the curable resin composition of the present invention is used as a conductive paste, for example, a method of dispersing fine conductive particles in the curable resin composition to obtain a composition for anisotropic conductive film, liquid at room temperature And a paste resin composition for circuit connection and an anisotropic conductive adhesive.

  As a method for obtaining an interlayer insulating material for a build-up substrate from the curable resin composition of the present invention, for example, the curable resin composition appropriately blended with rubber, filler, etc., spray coating method on a wiring board on which a circuit is formed, After applying using a curtain coating method or the like, it is cured. Then, after drilling a predetermined through-hole part etc. as needed, it treats with a roughening agent, forms the unevenness | corrugation by washing the surface with hot water, and metal-treats, such as copper. As the plating method, electroless plating or electrolytic plating treatment is preferable, and examples of the roughening agent include an oxidizing agent, an alkali, and an organic solvent. Such operations are sequentially repeated as desired, and a build-up base can be obtained by alternately building up and forming the resin insulating layer and the conductor layer having a predetermined circuit pattern. However, the through-hole portion is formed after the outermost resin insulating layer is formed. In addition, a resin-coated copper foil obtained by semi-curing the resin composition on the copper foil is thermocompression-bonded at 170 to 250 ° C. on a circuit board on which a circuit is formed, thereby forming a roughened surface and plating treatment. It is also possible to produce a build-up substrate by omitting the process.

  The method for producing an adhesive film for buildup from the curable resin composition of the present invention is, for example, a multilayer printed wiring board in which the curable resin composition of the present invention is applied on a support film to form a resin composition layer. And an adhesive film for use.

  When the curable resin composition of the present invention is used for a build-up adhesive film, the adhesive film is softened under the temperature condition of the laminate in the vacuum laminating method (usually 70 ° C. to 140 ° C.), and simultaneously with the lamination of the circuit board, It is important to show fluidity (resin flow) that allows resin filling in via holes or through holes present in a circuit board, and it is preferable to blend the above-described components so as to exhibit such characteristics.

  Here, the diameter of the through hole of the multilayer printed wiring board is usually 0.1 to 0.5 mm, and the depth is usually 0.1 to 1.2 mm. It is usually preferable to allow resin filling in this range. When laminating both surfaces of the circuit board, it is desirable to fill about 1/2 of the through hole.

  Specifically, the method for producing the adhesive film described above is, after preparing the varnish-like curable resin composition of the present invention, coating the varnish-like composition on the surface of the support film (Y), Further, it can be produced by drying the organic solvent by heating or blowing hot air to form the layer (X) of the curable resin composition.

  The thickness of the formed layer (X) is usually not less than the thickness of the conductor layer. Since the thickness of the conductor layer of the circuit board is usually in the range of 5 to 70 μm, the thickness of the resin composition layer is preferably 10 to 100 μm.

  In addition, the layer (X) in this invention may be protected with the protective film mentioned later. By protecting with a protective film, it is possible to prevent dust and the like from being attached to the surface of the resin composition layer and scratches.

  The above-mentioned support film and protective film are made of polyolefin such as polyethylene, polypropylene and polyvinyl chloride, polyethylene terephthalate (hereinafter sometimes abbreviated as “PET”), polyester such as polyethylene naphthalate, polycarbonate, polyimide, and further. Examples thereof include metal foil such as pattern paper, copper foil, and aluminum foil. In addition, the support film and the protective film may be subjected to a release treatment in addition to the mud treatment and the corona treatment.

  Although the thickness of a support film is not specifically limited, Usually, it is 10-150 micrometers, Preferably it is used in 25-50 micrometers. Moreover, it is preferable that the thickness of a protective film shall be 1-40 micrometers.

  The support film (Y) described above is peeled off after being laminated on a circuit board or after forming an insulating layer by heat curing. If the support film (Y) is peeled after the adhesive film is heat-cured, adhesion of dust and the like in the curing step can be prevented. In the case of peeling after curing, the support film is usually subjected to a release treatment in advance.

  Next, the method for producing a multilayer printed wiring board using the adhesive film obtained as described above is, for example, when the layer (X) is protected by a protective film, after peeling these layers ( X) is laminated on one side or both sides of the circuit board so as to be in direct contact with the circuit board, for example, by a vacuum laminating method. The laminating method may be a batch method or a continuous method using a roll. Further, the adhesive film and the circuit board may be heated (preheated) as necessary before lamination.

Lamination conditions are preferably a pressure bonding temperature (laminating temperature) of 70 to 140 ° C., a pressure bonding pressure of preferably 1 to 11 kgf / cm ² (9.8 × 10 ^{4 to} 107.9 × 10 ⁴ N / m 2), and air pressure. Lamination is preferably performed under a reduced pressure of 20 mmHg (26.7 hPa) or less.

  The method for obtaining the cured product of the present invention may be based on a general curing method for a curable resin composition, but for example, the heating temperature condition may be appropriately selected depending on the kind of curing agent to be combined and the use. However, what is necessary is just to heat the composition obtained by the said method in the temperature range about 20-250 degreeC.

  Therefore, by using the epoxy resin, the solvent solubility of the epoxy resin is dramatically improved, and when it is made into a cured product, there is little change in heat resistance after the heat history, and a low thermal expansion coefficient can be expressed. Applicable to printed wiring board materials. In addition, the epoxy resin can be easily and efficiently manufactured by the manufacturing method of the present invention, and a molecular design corresponding to the target level of performance described above becomes possible.

  Next, the present invention will be specifically described with reference to Examples and Comparative Examples. In the following, “parts” and “%” are based on mass unless otherwise specified. The melt viscosity at 150 ° C. and GPC, NMR and MS spectra were measured under the following conditions.

1) Softening point measurement method: JIS K7234

2) GPC: Measurement conditions are as follows.
Measuring device: “HLC-8220 GPC” manufactured by Tosoh Corporation
Column: Guard column “HXL-L” manufactured by Tosoh Corporation
+ "TSK-GEL G2000HXL" manufactured by Tosoh Corporation
+ "TSK-GEL G2000HXL" manufactured by Tosoh Corporation
+ Tosoh Corporation “TSK-GEL G3000HXL”
+ Tosoh Corporation “TSK-GEL G4000HXL”
Detector: RI (differential refractometer)
Data processing: “GPC-8020 Model II version 4.10” manufactured by Tosoh Corporation
Measurement conditions: Column temperature 40 ° C
Developing solvent Tetrahydrofuran
Flow rate: 1.0 ml / min Standard: The following monodisperse polystyrene having a known molecular weight was used in accordance with the measurement manual of “GPC-8020 Model II version 4.10”.
(Polystyrene used)
“A-500” manufactured by Tosoh Corporation
"A-1000" manufactured by Tosoh Corporation
"A-2500" manufactured by Tosoh Corporation
"A-5000" manufactured by Tosoh Corporation
“F-1” manufactured by Tosoh Corporation
"F-2" manufactured by Tosoh Corporation
“F-4” manufactured by Tosoh Corporation
“F-10” manufactured by Tosoh Corporation
“F-20” manufactured by Tosoh Corporation
“F-40” manufactured by Tosoh Corporation
“F-80” manufactured by Tosoh Corporation
“F-128” manufactured by Tosoh Corporation
Sample: A 1.0 mass% tetrahydrofuran solution filtered in terms of resin solids and filtered through a microfilter (50 μl).

3) ¹³ C-NMR: Measurement conditions are as follows.
Equipment: “JNM-ECA500” manufactured by JEOL Ltd.
Measurement mode: SGNNE (1H complete decoupling method of NOE elimination)
Solvent: Dimethyl sulfoxide Pulse angle: 45 ° C Pulse Sample concentration: 30 wt%
Integration count: 10,000 times 4) MS: JEOL Ltd. JMS-T100GC

Example 1
In a flask equipped with a thermometer, a dropping funnel, a condenser tube, a fractionating tube and a stirrer, 144 parts by mass of β-naphthol (1.0 mol), 167 parts by mass of isopropyl alcohol, 122 parts by mass of 37% formalin aqueous solution (1. 50 mol) and 20 parts by mass (0.25 mol) of 49% sodium hydroxide, the temperature was raised from room temperature to 75 ° C. with stirring, and the mixture was stirred at 75 ° C. for 1 hour. Subsequently, 47 parts by mass (0.25 mol) of 4,4′-biphenol was charged and further stirred at 75 ° C. for 8 hours. After completion of the reaction, neutralization was carried out by adding 30 parts by mass of primary sodium phosphate, followed by addition of 417 parts by mass of methyl isobutyl ketone, repeated washing with 104 parts by mass of water, drying under heating under reduced pressure, and biphenol- As a result, 198 parts by mass of naphthol resin (a-1) was obtained. The GPC chart of the obtained biphenol-naphthol resin (a-1) is shown in FIG. The hydroxyl group equivalent of the biphenol-naphthol resin (a-1) was 135 g / equivalent, and the content of the hexafunctional compound represented by the following structural formula (a) calculated from the GPC chart was 76.9%. .

  Next, 135 parts by mass of biphenol-naphthol resin (a-1) (hydroxyl group 1.0 equivalent) obtained by the above reaction and 463 parts by mass of epichlorohydrin while performing nitrogen gas purging on a flask equipped with a thermometer, a condenser, and a stirrer (5.0 mol) and 53 parts by mass of n-butanol were charged and dissolved while stirring. After the temperature was raised to 50 ° C., 220 parts by mass of a 20% aqueous sodium hydroxide solution (1.10 mol) was added over 3 hours, and the reaction was further continued at 50 ° C. for 1 hour. After completion of the reaction, stirring was stopped, the aqueous layer accumulated in the lower layer was removed, stirring was resumed, and unreacted epichlorohydrin was distilled off under reduced pressure at 150 ° C. Then, 300 parts by mass of methyl isobutyl ketone and 50 parts by mass of n-butanol were added to the resulting crude epoxy resin and dissolved. Further, 15 parts by mass of a 10% by mass sodium hydroxide aqueous solution was added to this solution and reacted at 80 ° C. for 2 hours, and then washing with 100 parts by mass of water was repeated three times until the pH of the cleaning solution became neutral. Next, the system was dehydrated by azeotropic distillation, and after microfiltration, the solvent was distilled off under reduced pressure to obtain 180 parts by mass of the desired epoxy resin (A-1). The GPC chart of the obtained epoxy resin (A-1) is shown in FIG. The epoxy equivalent of the Poxy resin (A-1) was 232 g / equivalent, and the softening point was 134 ° C. The content of the polyfunctional compound (x) calculated from the GPC chart is 54.6%, the content of the hexafunctional compound represented by the following structural formula (b) is 54.6%, and the bifunctional compound (y ) Content was 2.6%.

Example 2
Epoxy resin (A-2) 173 in the same manner as in Example 1 except that the content was changed to 89 parts by mass (1.10 mol) of 37% formalin aqueous solution and 93 parts by mass (0.50 mol) of 4,4′-biphenol. A mass part was obtained. FIG. 3 shows a GPC chart of the resulting epoxy resin (A-2), FIG. 4 shows an NMR chart, and FIG. 5 shows an MS spectrum. The epoxy equivalent of the epoxy resin (A-2) was 210 g / equivalent, and the softening point was 96 ° C. The content of the polyfunctional compound (x) calculated from the GPC chart is 62.1%, the content of the hexafunctional compound represented by the structural formula (b) is 22.3%, and the bifunctional compound (y ) Content was 6.2%. From the MS spectrum, a peak of 1146 indicating the hexafunctional compound represented by the structural formula (b) was detected.

Example 3
Except for changing to 108 parts by mass (0.75 mol) of β-naphthol, 91 parts by mass (1.12 mol) of 37% formalin aqueous solution, and 140 parts by mass (0.75 mol) of 4,4′-biphenol, Examples 1, 163 parts by mass of epoxy resin (A-3) was obtained. A GPC chart of the resulting epoxy resin (A-3) is shown in FIG. The epoxy equivalent of the epoxy resin (A-3) was 202 g / equivalent, and the softening point was 85 ° C. The content of the polyfunctional compound (x) calculated from the GPC chart is 48.1%, the content of the hexafunctional compound represented by the structural formula (b) is 6.8%, and the bifunctional compound (y ) Content was 11.0%.

Comparative Synthesis Example 1
A flask equipped with a thermometer, a dropping funnel, a condenser tube, a fractionating tube and a stirrer was charged with 505 parts by mass of α-naphthol (3.50 mol), 158 parts by mass of water, and 5 parts by mass of oxalic acid. The mixture was stirred while raising the temperature in 45 minutes. Subsequently, 177 parts by mass (2.45 mol) of a 42 mass% formalin aqueous solution was added dropwise over 1 hour. After completion of dropping, the mixture was further stirred at 100 ° C. for 1 hour, and then heated to 180 ° C. in 3 hours. After completion of the reaction, water remaining in the reaction system was removed under reduced pressure by heating to obtain 498 parts by mass of naphthol resin (a′-1). The hydroxyl group equivalent of the obtained naphthol resin (a′-1) was 154 g / equivalent.

  Next, 154 parts by mass of the naphthol resin (a′-1) obtained by the above reaction (hydroxyl group 1.0 equivalent) while performing nitrogen gas purging on a flask equipped with a thermometer, a condenser, and a stirrer was the same as in Example 1. Thus, 202 parts by mass of an epoxy resin (A′-1) was obtained. The epoxy equivalent of the obtained epoxy resin (A'-1) is 237 grams / equivalent, and the GPC chart is shown in FIG.

Comparative Synthesis Example 2
In a flask equipped with a thermometer, dropping funnel, condenser, fractionator, and stirrer, 144 parts by mass of β-naphthol (1.00 mol), 93 parts by mass of 4,4′-biphenol (0.50 mol), 237 parts by mass of methyl isobutyl ketone and 5 parts by mass of oxalic acid were charged and stirred while raising the temperature from room temperature to 80 ° C. in 45 minutes. Subsequently, 81 parts by mass (1.00 mol) of 37% formalin aqueous solution was added dropwise over 1 hour. After completion of the dropwise addition, the mixture was further stirred at 80 ° C. for 1 hour, and then the temperature was raised to 180 ° C. However, since the crystals were precipitated and stirring was difficult, the reaction was stopped. The GPC chart of the obtained phenol resin (a′-2) is shown in FIG. From the GPC chart, the content of the hexafunctional compound represented by the structural formula (a) was 0.0%.

Examples 4 to 6 and Comparative Example 1
In accordance with the formulation shown in Table 1 below, DIC-2090 (phenol novolac resin, hydroxyl group equivalent: 105 g / eq) as a curing agent and (A-1), (A-2), (A -3), (A′-1), and 2-ethyl-4-methylimidazole (2E4MZ) as a curing accelerator was blended, and finally the nonvolatile content (N.V.) of each composition was 58% by mass. It adjusted so that methyl ethyl ketone might be mixed. Subsequently, it was hardened on the following conditions, the laminated board was made as an experiment, and the thermal expansion coefficient and the physical property change were evaluated by the following method. The results are shown in Table 1.

<Laminate production conditions>
Base material: Glass cloth “# 2116” (210 × 280 mm) manufactured by Nitto Boseki Co., Ltd.
Number of plies: 6 Condition of prepreg: 160 ° C
Curing conditions: 200 ° C., 40 kg / cm ² for 1.5 hours, post-molding plate thickness: 0.8 mm
<Heat resistance change due to thermal history (amount of change in heat resistance: ΔTg): DMA (Tg difference between first measurement and second measurement)>
Using a viscoelasticity measuring device (DMA: solid viscoelasticity measuring device “RSAII” manufactured by Rheometric, rectangular tension method; frequency 1 Hz, temperature rising rate 3 ° C./min), elastic modulus change twice under the following temperature conditions Was measured at the temperature (Tg) at which the tan δ was maximized (the tan δ change rate was the largest).
Temperature conditions 1st measurement: temperature rise from 35 ° C. to 275 ° C. at 3 ° C./min 2nd measurement: temperature rise from 35 ° C. to 330 ° C. at 3 ° C./min Each obtained temperature difference was evaluated as ΔTg.

<Coefficient of thermal expansion>
The laminate was cut into a size of 5 mm × 5 mm × 0.8 mm, and a thermomechanical analysis was performed in a compression mode using a thermomechanical analyzer (TMA: SS-6100 manufactured by Seiko Instruments Inc.) as a test piece. .
Measurement conditions Measurement weight: 88.8mN
Temperature increase rate: 2 times at 10 ° C / minute Measurement temperature range: -50 ° C to 300 ° C
The measurement under the above conditions was carried out twice for the same sample, and the average linear expansion coefficient in the temperature range of 40 ° C. to 60 ° C. in the second measurement was evaluated as the thermal expansion coefficient.

Abbreviations in Table 1 are as follows.
TD-2090: Phenol novolac type phenol resin (“TD-2090” manufactured by DIC Corporation, hydroxyl equivalent: 105 g / eq)
2E4MZ: Curing accelerator (2-ethyl-4-methylimidazole)

Claims (12)

An epoxy resin obtained by polyglycidyl etherification of a polycondensate of 4,4′-biphenol, a β-naphthol compound, and formaldehyde, in which the following structural formula (1)

(In the formula, R ¹ and R ² each independently represent a hydrogen atom, an alkyl group having 1 to 4 carbon atoms, or an alkoxy group having 1 to 4 carbon atoms, and G represents a glycidyl group. Is 1 or 2, m is an integer of 0-2.)
The epoxy resin characterized by including the polyfunctional compound (x) represented by these, and the content rate of this polyfunctional compound (x) is 30% or more by the area ratio in GPC measurement. A hexafunctional compound (x6) in which n and m are both 2 in the general formula (1) is contained, and the content of the hexafunctional compound (x6) is 5% or more in terms of an area ratio in GPC measurement. 1. The epoxy resin according to 1. In addition to the polyfunctional compound (x), the following structural formula (2)

(In the formula, G represents a glycidyl group.)
And the content ratio of the polyfunctional compound (x) is 30 to 95% in terms of area ratio in GPC measurement, and the bifunctional compound (x) The epoxy resin according to claim 1, wherein the content of y) is a ratio of 1 to 25% in terms of area ratio in GPC measurement. The epoxy resin according to claim 1, wherein the epoxy equivalent is in a range of 170 to 300 g / eq. The epoxy resin according to claim 1, wherein the softening point is in the range of 80 to 140 ° C. A curable resin composition comprising the epoxy resin according to any one of claims 1 to 5 and a curing agent as essential components. A cured product obtained by curing reaction of the curable resin composition according to claim 6. A printed wiring board obtained by impregnating a reinforcing base material with a resin composition obtained by further blending an organic solvent with the curable resin composition according to claim 6 and superimposing a copper foil thereon, followed by thermocompression bonding. A β-naphthol compound and formaldehyde are reacted in the presence of an organic solvent and an alkali catalyst, and then 4,4′-biphenol is added and reacted in the presence of formaldehyde to obtain a biphenol-naphthol resin (step 1), and then A method for producing an epoxy resin, wherein the resulting biphenol-naphthol resin is reacted with epihalohydrin (step 2). In the presence of an organic solvent and an alkali catalyst, 4,4′-biphenol, a β-naphthol compound, and formaldehyde are reacted to obtain a biphenol-naphthol resin (step 1), and then epihalohydrin is added to the obtained biphenol-naphthol resin. The manufacturing method of the epoxy resin made to react (process 2). The alkali catalyst is sodium hydroxide, potassium hydroxide, metallic sodium, metallic lithium, sodium hydride, sodium carbonate or potassium carbonate, and the amount used is 4,4′-biphenol and β-naphthol which are raw material components The method for producing an epoxy resin according to claim 9 or 10, wherein the amount is 0.01 to 2.0 times the molar amount of the total number of phenolic hydroxyl groups of the compound. The organic solvent is methyl cellosolve, isopropyl alcohol, ethyl cellosolve, toluene, xylene, or methyl isobutyl ketone, and the amount used is 4,4′-biphenol and β-naphthol compound as a raw material. It is the range of 5-70 mass parts per, The manufacturing method of the epoxy resin in any one of Claims 9-11.

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