JP2013087212A - Epoxy resin, curable resin composition, cured product thereof, and printed circuit board - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an epoxy resin of which shows a small change in heat resistance after subjected to a thermal history and a low thermal expansion in a cured product, a curable resin composition having the characteristics, the cured product thereof, and a printed circuit board which exhibits a small change in heat resistance after subjected to a thermal history and a low thermal expansion.SOLUTION: The new epoxy resin includes (A) diglycidyl ether of bisphenol and (B) polyglycidyl ether of bisphenol novolac. The epoxy resin is characterized in that when it is measured byC-NMR, the ratio [(a)/(b)] of the integral value of (a) the peak appearing at 151-153 ppm to the integral value of (b) the peak appearing at 151-158 is in the range of 0.05 to 0.14. A curable resin composition uses the epoxy resin as the major component.

Description

  The present invention is a curable resin composition that 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 encapsulants, paints, casting applications, etc. The present invention relates to a printed wiring board using a cured product, its cured product, an epoxy resin, and the curable resin composition.

  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, along with the trend toward miniaturization and higher performance of electronic equipment, there is a significant trend toward higher density due to narrower wiring pitches in 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, high melting point solder that does not use lead has become mainstream due to laws and regulations for environmental problems, etc., and this lead-free solder has a use temperature that is about 20-40 ° C. higher than conventional eutectic solder. Therefore, the curable resin composition is required to have higher heat resistance than ever before.
Printed wiring boards are generally made by curing and integrally molding a curable resin composition based on an epoxy resin and a glass woven fabric. Improvement of the epoxy resin is required to achieve high heat resistance and low thermal expansion. It has been demanded.

  In order to meet such a demand, a technique using a bisphenol A novolac type epoxy resin is known in order to enhance the aromatic attribute in the epoxy resin structure and improve the heat resistance. For example, Patent Document 1 listed below discloses bisphenol A. A technique for improving the heat resistance by increasing the molecular weight of a novolak-type A novolak-type epoxy resin is known.

  However, the bisphenol A novolak type epoxy resin of Patent Document 1 has a high degree of three-dimensional cross-linking as the molecular weight increases, the reactivity of the epoxy group in the epoxy resin becomes low, and the heat resistance change after the heat history changes. In addition to being easily generated, the thermal expansion coefficient was inevitably low.

Japanese Patent Publication No. 64-90215

  Accordingly, the problem to be solved by the present invention is that an epoxy resin that exhibits little thermal resistance change after heat history and exhibits low thermal expansion in the cured product, a curable resin composition having the performance, and the cured product An object of the present invention is to provide a printed wiring board that has little change in heat resistance after heat history and is excellent in low thermal expansion.

As a result of intensive studies to solve the above-mentioned problems, the inventors of the present invention have an epoxy resin having a polyglycidyl etherified resin structure of a bisphenol novolac resin, and the epoxy resin is measured by ¹³ C-NMR. When the ratio of two specific peaks is within a predetermined range, the present inventors have found that an epoxy resin having a small heat resistance change after heat history and excellent in heat expansion is obtained, and has completed the present invention.

That is, the present invention is an epoxy resin containing diglycidyl ether (A) of bisphenol and polyglycidyl ether (B) of bisphenol novolak, and when the epoxy resin mixture is measured by C ¹³ -NMR, The ratio [(a) / (b)] of the integrated value of the peak (b) appearing at 151 to 158 ppm and the integrated value of the peak (a) appearing at 151 to 153 ppm is in the range of 0.05 to 0.14. It is related with the epoxy resin characterized by being.

  The present invention further relates to a curable resin composition comprising 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 relates to a printed wiring 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. Regarding the substrate.

  According to the present invention, there is little change in heat resistance after thermal history in the cured product, and an epoxy resin that exhibits low thermal expansion, a curable resin composition having the performance, the cured product, and heat resistance after thermal history. It is possible to provide a printed wiring board that exhibits little change in properties and is excellent in low thermal expansion.

1 is a GPC chart of the bisphenol F novolac type epoxy resin (A-2) obtained in Example 1. FIG. 2 is a C ¹³ -NMR chart of the bisphenol F novolac type epoxy resin (A-2) obtained in Example 1. FIG. FIG. 3 is a GPC chart of the bisphenol F novolac type epoxy resin (A-4) obtained in Example 2. 4 is a C ¹³ -NMR chart of bisphenol F novolac type epoxy resin (A-4) obtained in Example 2. FIG. FIG. 5 is a GPC chart of the bisphenol F novolac type epoxy resin (A-6) obtained in Example 3. 6 is a C ¹³ -NMR chart of bisphenol F novolac type epoxy resin (A-6) obtained in Example 3. FIG.

Hereinafter, the present invention will be described in detail.
As described above, the epoxy resin of the present invention is a mixture containing diglycidyl ether (A) of bisphenol and polyglycidyl ether (B) of bisphenol novolak, and when measured by C ¹³ -NMR, 151 The ratio [(a) / (b)] of the integrated value of the peak (b) appearing at ˜158 ppm and the integrated value of the peak (a) appearing at 151 to 153 ppm is in the range of 0.05 to 0.14. It is characterized by being.

Here, the integrated value of the peak (b) in ¹³ C-NMR is specifically the integrated value of the peak based on all the carbon atoms bonded to the glycidyloxy group in the epoxy resin, while the peak (a Specifically, the integral value of the following formula I

（式中、Ｇｌはグリシジル基を、Ｘは、原料ビスフェノールがビスフェノールＦの場合はメチレン基を、ビスフェノールＡの場合は、２，２−プロピレン基を、ビスフェノールＳの場合はスルホニル基をそれぞれ表す）で示される様に、グリシジルオキシ基が結合する芳香核の２，４，６−位に結合部位を有する芳香核における、グリシジルオキシ基の結合する炭素原子に基づくピークの積分値である。よって、これらの比率［（ａ）／（ｂ）］が０．０５〜０．１４の範囲にある場合には、エポキシ樹脂中に前記構造式Ｉで表される構造部位が少なくなり、全体としてリニア優位な樹脂構造を形成する。従って、本発明のエポキシ樹脂の前駆体フェノール樹脂が、ビスフェノールとビスフェノールノボラックとの混合物であるにも拘わらず、比較的リニア優位な樹脂構造となり、硬化反応時におけるエポキシ基の反応性が高まり熱履歴後の耐熱性変化、例えば、ＤＭＡ法によるガラス転移点を２回測定した場合の変化（ΔＴｇ）の少ないエポキシ樹脂となる。また、エポキシ樹脂の芳香環の重なりや、エポキシ基の反応性向上に伴い、硬化物における線膨張係数も低いものとなる。

(In the formula, Gl represents a glycidyl group, X represents a methylene group when the raw material bisphenol is bisphenol F, a 2,2-propylene group when bisphenol A is used, and a sulfonyl group when bisphenol S is used) As shown in Fig. 4, the integrated value of the peak based on the carbon atom to which the glycidyloxy group is bonded in the aromatic nucleus having a binding site at the 2,4,6-position of the aromatic nucleus to which the glycidyloxy group is bonded. Therefore, when these ratios [(a) / (b)] are in the range of 0.05 to 0.14, the number of structural sites represented by the structural formula I in the epoxy resin is reduced, and as a whole Forms a linear-dominant resin structure. Therefore, although the epoxy resin precursor phenol resin of the present invention is a mixture of bisphenol and bisphenol novolac, it has a relatively linear-dominant resin structure, which increases the reactivity of the epoxy group during the curing reaction and heat history. It becomes an epoxy resin with little change (ΔTg) when the subsequent heat resistance change, for example, the glass transition point by the DMA method is measured twice. Moreover, the linear expansion coefficient in a cured product also becomes low with the overlap of the aromatic ring of an epoxy resin, or the reactivity improvement of an epoxy group.

  Here, the epoxy resin specifically contains bisphenol diglycidyl ether (A) and bisphenol novolac polyglycidyl ether (B) as described above. In terms of the area ratio of GPC measurement measured under the above conditions, it is preferable that the ratio of the diglycidyl ether (A) of bisphenol in the epoxy resin is 5 to 40% from the viewpoint of an epoxy resin having a small ΔTg. .

<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).

  Specific examples of bisphenol diglycidyl ether (A) include diglycidyl ether of bisphenol F, diglycidyl ether of bisphenol A, and diglycidyl ether of bisphenol S. In the present invention, diglycidyl ether of bisphenol F is particularly preferable in terms of achieving both low viscosity and high heat resistance.

  On the other hand, the polyglycidyl ether (B) of bisphenol novolac constituting the epoxy resin of the present invention is specifically a so-called bisphenol novolac resin in which bisphenols such as bisphenol F, bisphenol A, and bisphenol S are knotted through a methylene bond. Has a structure obtained by glycidyl etherification. In the present invention, the polyglycidyl ether (B) of the bisphenol novolac is preferably a bisphenol F novolac type epoxy resin from the viewpoint of achieving both low viscosity and high heat resistance.

  Moreover, it is preferable from the point of the moldability and the impregnation property to a base material that the said epoxy resin has the softening point in the range of 50-100 degreeC. The number average molecular weight (Mn) in the GPC measurement is in the range of 400 to 2000, and the ratio of the number average molecular weight (Mn) in the GPC measurement to the weight average molecular weight (Mw) in the GPC measurement [(Mw) / (Mn)] is also preferably in the range of 1.5 to 15.0 from the viewpoints of moldability and impregnation into the substrate. In the present invention, the molecular weight distribution [(Mw) / (Mn)] is as narrow as 1.5 to 15.0, so that the heat resistance change after the heat history is small. From the standpoint of such an effect, the number average molecular weight (Mn) is in the range of 600 to 1300, and the ratio of the number average molecular weight (Mn) in GPC measurement to the weight average molecular weight (Mw) in GPC measurement [ (Mw) / (Mn)] is preferably in the range of 2.0 to 10.0.

  Here, the number average molecular weight (Mn) and the weight average molecular weight (Mw) are values measured by GPC under the above-described conditions.

  The epoxy resin of the present invention described in detail above includes, for example, a step of producing bisphenol novolac resin by reacting bisphenol and formaldehyde in the presence of an acid catalyst and water (step 1), The process of producing an epoxy resin by reacting a novolak resin with epihalohydrin to glycidyl ether (process 2) is an essential production process, and the amount of water in the reaction system in the process 1 is changed to bisphenol, formaldehyde And epoxy resin which is a mixture containing diglycidyl ether (A) of bisphenol and polyglycidyl ether (B) of bisphenol novolac by reacting in a range of 25 to 50% by mass with respect to the total amount of water. Can be produced industrially. In the present invention, by adjusting the amount of water in the reaction system in Step 1 to a range of 25 to 50% by mass, the abundance of the structural unit II can be increased in the finally obtained epoxy resin. At the same time, the molecular weight distribution can be narrowed, and the heat resistance and heat expansion after heat history can be dramatically improved.

  Here, as for the bisphenol used at the process 1, bisphenol A, bisphenol F, bisphenol S etc. are mentioned, for example. In the present invention, bisphenol F is particularly preferable in terms of achieving both low viscosity and high heat resistance. On the other hand, the formaldehyde used here may be a formalin solution in an aqueous solution state or paraformaldehyde in a solid state.

  Further, the reaction of bisphenol and formaldehyde in Step 1 specifically includes a method of heating bisphenol and formaldehyde in the presence of a catalyst and water. Here, the reaction rate of bisphenol and formaldehyde is a ratio in which formaldehyde becomes 0.01 to 1.0 mol with respect to 1 mol of bisphenol, and the heat resistance of the epoxy resin finally obtained is maintained at a high level. However, it is preferable from the viewpoint of having an appropriate viscosity and good moldability and impregnation into the substrate. Further, the catalyst used here is not particularly limited, but an acid catalyst is preferable, and examples thereof include inorganic acids such as hydrochloric acid, sulfuric acid and phosphoric acid, methanesulfonic acid, p-toluenesulfonic acid, oxalic acid and the like. Examples include Lewis acids such as organic acids, boron trifluoride, anhydrous aluminum chloride, and zinc chloride. The amount used is preferably in the range of 0.01 to 10.0% by mass with respect to the total mass of the charged raw materials.

  Moreover, as reaction temperature, it is 40-250 degreeC normally, and the range of 100-200 degreeC is more preferable.

  The intermediate product obtained in Step 1 of the present invention is a mixture of bisphenol novolac and bisphenol remaining as an unreacted component. Here, the molecular weight distribution of the intermediate product is narrowed by setting the amount of water in the reaction system in the reaction of Step 1 to a range of 25 to 50% by mass in the total mass of bisphenol, formaldehyde, and water. be able to.

  Here, when using formalin as a raw material, the amount of water in the reaction system can be adjusted by adding water derived therefrom and, if necessary, water into the system.

  Moreover, when performing reaction of the process 1, an organic solvent can be used as needed. Specific examples of the organic solvent that can be used include, but are not limited to, methyl cellosolve, ethyl cellosolve, toluene, xylene, and methyl isobutyl ketone. The amount of the organic solvent used is usually 10 to 500% by mass, preferably 30 to 250% by mass, based on the total mass of the charged raw materials.

  Moreover, when the coloring of the phenol compound obtained is large, in order to suppress it, you may add antioxidant and a reducing agent. The antioxidant is not particularly limited, and examples thereof include hindered phenol compounds such as 2,6-dialkylphenol derivatives, divalent sulfur compounds, and phosphite compounds containing trivalent phosphorus atoms. be able to. Although it does not specifically limit as said reducing agent, For example, hypophosphorous acid, phosphorous acid, thiosulfuric acid, sulfurous acid, hydrosulfite, these salts, zinc, etc. are mentioned.

  After completion of the reaction, the reaction mixture is neutralized or washed with water until the pH value of the reaction mixture becomes 3 to 7, preferably 4 to 7. What is necessary is just to perform a neutralization process and a water washing process in accordance with a conventional method. For example, when an acid catalyst is used, basic substances such as sodium hydroxide, potassium hydroxide, sodium carbonate, ammonia, triethylenetetramine, and aniline can be used as the neutralizing agent. At the time of neutralization, a buffer such as phosphoric acid may be added in advance, or the pH may be adjusted to 3 to 7 with oxalic acid after the base side is once used.

  After neutralization or washing with water, unreacted raw materials, organic solvents and by-products are distilled off under heating under reduced pressure to concentrate the product, and the desired bisphenol novolac resin can be obtained. The unreacted raw material recovered here can be reused. It is more preferable to introduce a microfiltration step into the processing operation after the reaction is completed because inorganic salts and foreign substances can be purified and removed.

  Next, the step 2 is a step of producing a target epoxy resin by reacting a mixture of the bisphenol novolak and bisphenol obtained in the step 1 with an 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 mixture, and the number of moles 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. The basic catalyst may be solid or an aqueous solution thereof. When an aqueous solution is used, it is continuously added and water and epihalohydrin are continuously distilled from the reaction mixture under reduced pressure or normal pressure. Alternatively, the solution may be further separated to remove water, and the epihalohydrin is continuously returned to the reaction mixture.

  In addition, in the first batch of epoxy resin production, all of the epihalohydrin used for charging is new in industrial production, but the subsequent batch and later are consumed by reaction with epihalohydrins recovered from the crude reaction product. It is preferable to use in combination with a new epihalohydrin corresponding to the amount disappeared in minutes. 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) A polyhydric phenol compound is mentioned.

  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 novolac type epoxy resin,
Examples thereof include a naphthol aralkyl type epoxy resin, a naphthol-phenol co-condensed novolac type epoxy resin, a naphthol-cresol co-condensed novolac type epoxy resin, an aromatic hydrocarbon formaldehyde resin-modified phenol resin type epoxy resin, and a biphenyl novolac type epoxy resin. 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, propylene glycol monomethyl ether acetate, etc. 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 thermosetting resin composition is a non-halogen flame retardant that substantially does not contain a halogen atom in order to exert flame retardancy, for example, in the field of printed wiring boards, as long as the reliability is not lowered. May be blended.

  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- Examples thereof include cyclic organophosphorus compounds such as dihydrooxynaphthyl) -10H-9-oxa-10-phosphaphenanthrene = 10-oxide, 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 phenolic compounds such as melam and other amino compounds such as phenol, cresol, xylenol, butylphenol, nonylphenol, melamine compounds such as melamine, benzoguanamine, acetoguanamine, formguanamine, and formaldehyde, (iii) (Ii) a mixture of a co-condensate of (ii) and a phenol resin such as a phenol formaldehyde condensate; (iv) the above (ii), (iii) further modified with paulownia oil, isomerized linseed oil, etc. And the like.

  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 process 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, when it is made into a cured product, there is little change in heat resistance after heat history, a low coefficient of thermal expansion can be expressed, and it can be applied to the latest 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 softening point, GPC, and NMR 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.
Device: AL-400 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

Example 1
In a flask equipped with a thermometer, dropping funnel, condenser, fractionator, and stirrer, 200 parts by mass of bisphenol F (1.00 mol), 47.2 parts by mass of a 42% by weight aqueous formaldehyde solution (0.66 mol), water 60 parts by mass and 0.6 parts by mass (0.0068 mol) of oxalic acid were charged and stirred at room temperature while blowing nitrogen. Then, it heated up at 100 degreeC and stirred for 3 hours. Thereafter, the temperature was raised to 180 ° C. in 3 hours. After completion of the reaction, water remaining in the reaction system was removed under heating and reduced pressure to obtain 205 parts of bisphenol F novolac resin (A-1). The obtained bisphenol F novolak resin (A-1) had a hydroxyl group equivalent of 105 grams / equivalent and a softening point of 100 ° C. The ratio (a / b) of peak integration values in C ¹³ -NMR of the obtained bisphenol F novolak resin (A-1) was 0.11.

Next, 105 parts by mass of bisphenol F novolak resin (A-1) (hydroxyl group 1.0 equivalent) and 463 parts by mass of epichlorohydrin obtained by the above reaction while purging a flask equipped with a thermometer, a condenser and a stirrer with nitrogen gas purge. (5.0 mol) and 53 parts by mass of n-butanol were charged and dissolved. 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, unreacted epichlorohydrin was distilled off under reduced pressure at 150 ° C. Then, 300 parts of methyl isobutyl ketone and 50 parts by weight of n-butanol were added to the crude epoxy resin thus obtained 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. Then, washing with 100 parts of water was repeated three times until the pH of the washing solution became neutral. Next, the system was dehydrated by azeotropic distillation, and after passing through microfiltration, the solvent was distilled off under reduced pressure to obtain 153 parts by mass of the desired bisphenol F novolac type epoxy resin (A-2). The obtained bisphenol F novolac type epoxy resin (A-2) has an epoxy equivalent of 188 g / equivalent, a softening point of 68 ° C., a number average molecular weight (Mn) of 996, a weight average molecular weight (Mw) of 4455, a ratio [( Mw) / (Mn)] was 4.5, and the peak integration value ratio a / b in C ¹³ -NMR was 0.09. Moreover, the content rate of the bisphenol F diglycidyl ether in a bisphenol F novolak-type epoxy resin (A-2) was 11.7% on the basis of the area ratio by GPC measurement. A GPC chart of the epoxy resin (A-2) is shown in FIG. 1, and a C ¹³ -NMR chart is shown in FIG.

Example 2
A flask equipped with a thermometer, a dropping funnel, a condenser tube, a fractionating tube, and a stirrer, 200 parts by mass of bisphenol F (1.00 mol), 39.3 parts by mass of a 42% by mass aqueous formaldehyde solution (0.55 mol), water 60 parts by mass and 0.6 parts by mass (0.0068 mol) of oxalic acid were charged and stirred at room temperature while blowing nitrogen. Then, it heated up at 100 degreeC and stirred for 3 hours. Thereafter, the temperature was raised to 180 ° C. in 3 hours. After completion of the reaction, water remaining in the reaction system was removed under heating and reduced pressure to obtain 203 parts of bisphenol F novolac resin (A-3). The obtained bisphenol F novolak resin (A-3) had a hydroxyl group equivalent of 105 grams / equivalent and a softening point of 87 ° C. The ratio (a / b) of peak integration values in C ¹³ -NMR of the obtained bisphenol F novolak resin (A-3) was 0.07.

Next, 105 parts by mass of the bisphenol F novolak resin (A-3) obtained by the above reaction while performing a nitrogen gas purge on a flask equipped with a thermometer, a condenser tube, and a stirrer, and 463 parts by mass of epichlorohydrin (5.0 mol) and 53 parts by mass of n-butanol were charged and dissolved. 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, unreacted epichlorohydrin was distilled off under reduced pressure at 150 ° C. Then, 300 parts of methyl isobutyl ketone and 50 parts by weight of n-butanol were added to the crude epoxy resin thus obtained 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. Then, washing with 100 parts of water was repeated three times until the pH of the washing solution became neutral. Next, the system was dehydrated by azeotropic distillation, and after microfiltration, the solvent was distilled off under reduced pressure to obtain 153 parts by mass of the desired bisphenol F novolac type epoxy resin (A-4). The obtained bisphenol F novolac type epoxy resin (A-4) has an epoxy equivalent of 188 g / equivalent, a softening point of 56 ° C., a number average molecular weight (Mn) of 644, a weight average molecular weight (Mw) of 1208, and a ratio [( Mw) / (Mn)] was 1.9, and the peak integration ratio a / b in C ¹³ -NMR was 0.06. Moreover, the content rate of the bisphenol F diglycidyl ether in a bisphenol F novolak-type epoxy resin (A-4) was 23.0% on the basis of the area ratio by GPC measurement. A GPC chart of the epoxy resin (A-4) is shown in FIG. 3, and a C ¹³ -NMR chart is shown in FIG.

Example 3
A flask equipped with a thermometer, a dropping funnel, a condenser tube, a fractionating tube, and a stirrer, 200 parts by mass of bisphenol F (1.00 mol), 53.6 parts by mass of a 42% by mass formaldehyde aqueous solution (0.75 mol), water 60 parts by mass and 0.6 parts by mass (0.0068 mol) of oxalic acid were charged and stirred at room temperature while blowing nitrogen. Then, it heated up at 100 degreeC and stirred for 3 hours. Thereafter, the temperature was raised to 180 ° C. in 3 hours. After completion of the reaction, water remaining in the reaction system was removed under heating and reduced pressure to obtain 206 parts of bisphenol F novolac resin (A-5). The obtained bisphenol F novolak resin (A-5) had a hydroxyl group equivalent of 105 grams / equivalent and a softening point of 115 ° C. The ratio (a / b) of integral values of peaks in C ¹³ -NMR of the obtained bisphenol F novolak resin (A-5) was 0.13.

Next, 105 parts by mass of the bisphenol F novolac resin (A-5) obtained by the above reaction (1.0 equivalent of hydroxyl group) 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. 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, unreacted epichlorohydrin was distilled off under reduced pressure at 150 ° C. Then, 300 parts of methyl isobutyl ketone and 50 parts by weight of n-butanol were added to the crude epoxy resin thus obtained 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. Then, washing with 100 parts of water was repeated three times until the pH of the washing solution became neutral. Next, the system was dehydrated by azeotropic distillation, and after microfiltration, the solvent was distilled off under reduced pressure to obtain 153 parts by mass of the desired bisphenol F novolac type epoxy resin (A-6). The obtained bisphenol F novolac type epoxy resin (A-6) has an epoxy equivalent of 188 g / equivalent, a softening point of 79 ° C., a number average molecular weight (Mn) of 1201, a weight average molecular weight (Mw) of 10131, and a ratio [( Mw) / (Mn)] was 8.4, and the peak integration ratio a / b in C ¹³ -NMR was 0.12. Moreover, the content rate of the bisphenol F diglycidyl ether in the bisphenol F novolak-type epoxy resin (A-6) was 10.0% on the basis of the area ratio by GPC measurement. FIG. 5 shows a GPC chart of the epoxy resin (A-6), and FIG. 6 shows a C ¹³ -NMR chart.

Comparative Example 1
A flask equipped with a thermometer, a dropping funnel, a condenser tube, a fractionating tube, and a stirrer was mixed with 200 parts by mass of bisphenol F (1.00 mol), 47.2 parts by mass of a 42% by weight aqueous formaldehyde solution (0.66 mol), and oxalic acid. 0.6 parts by mass (0.0068 mol) was charged and stirred at room temperature while blowing nitrogen. Then, it heated up at 100 degreeC and stirred for 3 hours. Thereafter, the temperature was raised to 180 ° C. in 3 hours. After completion of the reaction, water remaining in the reaction system was removed under heating and reduced pressure to obtain 205 parts of bisphenol F novolac resin (A-7). The obtained bisphenol F novolak resin (A-7) had a hydroxyl group equivalent of 105 grams / equivalent.
Next, 105 parts by mass of the bisphenol F novolak resin (A-7) obtained by the above reaction while performing a nitrogen gas purge on a flask equipped with a thermometer, a condenser, and a stirrer, and 463 parts by mass of epichlorohydrin (5.0 mol) and 53 parts by mass of n-butanol were charged and dissolved. 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, unreacted epichlorohydrin was distilled off under reduced pressure at 150 ° C. Then, 300 parts of methyl isobutyl ketone and 50 parts by weight of n-butanol were added to the crude epoxy resin thus obtained 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. Then, washing with 100 parts of water was repeated three times until the pH of the washing solution became neutral. Next, the system was dehydrated by azeotropic distillation, and after microfiltration, the solvent was distilled off under reduced pressure to obtain 153 parts by mass of the desired bisphenol F novolac type epoxy resin (A-8). The obtained bisphenol F novolac type epoxy resin (A-8) has an epoxy equivalent of 188 g / equivalent, a number average molecular weight (Mn) of 925, a weight average molecular weight (Mw) of 6753, and a ratio (Mw / Mn) of 7. In 3, C ¹³ -NMR, the peak integrated value ratio a / b was 0.17.

Examples 4-6, Comparative Example 2
In accordance with the formulation shown in Table 2 below, as a curing agent, phenol novolac resin (“TD-2090” manufactured by DIC Corporation, hydroxyl equivalent: 105 g / eq), epoxy resin (A-2), (A-4), (A-6), (A-8), 2-ethyl-4-methylimidazole (2E4MZ) is blended as a curing accelerator, and finally the nonvolatile content (N.V.) of each composition is 58% by mass. It adjusted by mix | blending methyl ethyl ketone so that it might become.
Subsequently, it was hardened on the following conditions, the laminated board was made as an experiment, and the thermal expansion coefficient and the heat resistance change by a thermal history were evaluated by the following method. The results are shown in Table 2.

<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-mold 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 largest).
Temperature condition 1st measurement: temperature increase from 25 ° C. to 250 ° C. at 3 ° C./min 2nd measurement: temperature increase from 25 ° C. to 250 ° 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.

表１中の略号は以下の通りである。
ＴＤ−２０９０：フェノールノボラック型フェノール樹脂（ＤＩＣ(株)製「ＴＤ−２０９０」、水酸基当量：１０５ｇ／ｅｑ）
２Ｅ４ＭＺ：硬化促進剤（２−エチル−４−メチルイミダゾール）

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 (8)

An epoxy resin containing diglycidyl ether (A) of bisphenol and polyglycidyl ether (B) of bisphenol novolac, and a peak appearing at 151 to 158 ppm when the epoxy resin is measured by C ¹³ -NMR The ratio [(a) / (b)] between the integrated value of (b) and the integrated value of the peak (a) appearing at 151 to 153 ppm is in the range of 0.05 to 0.14. Epoxy resin. The epoxy resin according to claim 1, wherein the softening point is in the range of 50 to 100 ° C. The epoxy resin according to claim 1, wherein the polyglycidyl ether of the bisphenol novolac resin is a bisphenol F type epoxy resin. The epoxy resin has a number average molecular weight (Mn) in the range of 400 to 2000 in GPC measurement, and a ratio of the number average molecular weight (Mn) in GPC measurement to the weight average molecular weight (Mw) in GPC measurement [( Mw) / (Mn)] is in a range of 1.5 to 15.0. A step of producing an intermediate product by reacting bisphenol with formaldehyde in the presence of an acid catalyst and water (Step 1), and then reacting the intermediate product with an epihalohydrin to glycidyl ether to produce an epoxy resin mixture And the amount of water in the reaction system in the step 1 is 25 to 50% by mass with respect to the total mass of bisphenol, formaldehyde, and water. A method for producing an epoxy resin, characterized by reacting within a range. A curable resin composition comprising the epoxy resin according to any one of claims 1 to 4 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, impregnating the reinforcing base material, and heating and pressing the copper foil.

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