JP7326708B2 - Method for producing phenolic resin - Google Patents

Description

The present invention relates to a method for producing a phenolic resin useful as a component of thermosetting resin compositions.

In recent years, as the performance of information and communication equipment has been enhanced and the density thereof has been increased, printed wiring boards are required to have a performance adapted thereto. A cured product of a thermosetting resin composition is used as an insulating material for forming a printed wiring board. Compositions are commonly used.

Epoxy resin compositions are required to have further improved properties depending on the application when used in electrical and electronic parts. For example, when used in automotive semiconductors used in harsh environments or in electronic components that use high voltage, epoxy resin compositions are required to have a high glass transition temperature (Tg) and excellent thermal decomposition resistance. be done. Various studies have been made on the configuration of an epoxy resin composition for obtaining a cured product having a high glass transition temperature and high thermal decomposition resistance.

For example, Patent Document 1 describes that a phenol novolac resin obtained by reacting phenol, resorcin, and 4,4′-di(chloromethyl)biphenyl is reacted with epichlorohydrin to produce an epoxy resin. ing.
Patent Document 2 describes a composition containing an epoxy compound and a phenol compound having a divalent phenol skeleton in a specific proportion, and a specific copolymer.

JP-A-2013-43958 JP 2016-160317 A

The compositions described in Patent Literature 1 and Patent Literature 2 are based on biphenyl aralkyl resins with high thermal decomposition temperatures, and are biphenyl aralkyl resins with excellent thermal decomposition resistance by increasing the number of functional groups by changing some of the phenols to resorcinol or the like. The glass transition temperature of the cured product is increased while maintaining the characteristics of . However, if the phenol resin used as a component of the epoxy resin composition is designed so that the cured product has a high glass transition temperature, there is a problem that the melt viscosity of the phenol resin increases. Patent Documents 1 and 2 do not describe the problem that the melt viscosity of the phenol resin increases when the phenol resin is designed so that the cured product has a high glass transition temperature, and there is no description of means for lowering the melt viscosity of the phenol resin.

The present invention is useful for obtaining a cured product having a high glass transition temperature and thermal decomposition resistance, and a phenol resin having a low melt viscosity, a method for producing the same, a thermosetting resin composition containing the above phenol resin, and the An object of the present invention is to provide a cured product of a thermosetting resin composition, a semiconductor sealing material containing the thermosetting resin composition, and a semiconductor device containing the cured product.

The present invention provided to solve the above problems is as follows.

[1] A first reaction in which resorcin and formaldehyde are reacted, a product of the first reaction, a monohydric phenol, and a biphenyl compound represented by the following general formula (2) are reacted in the presence of a sulfonic acid catalyst. A phenol having a melt viscosity at 150 ° C. of 50 to 400 mPa s, containing a component having a unit represented by the following formula (A) and / or formula (B) and bisphenol F, and a second reaction. A method for producing resin.
(X in formula (2) is a methoxy group, a hydroxyl group, or a halogen.)


(p2 and p3 in formula (A) and formula (B) may be the same or different and are 0 or 1; q2 and q3 may be the same or different and are 0, 1 or ² ; R3 is a methyl group. ⁾

[2] The method for producing a phenolic resin according to [1], wherein the reaction temperature in the second reaction is 140°C or higher.
[3] The method for producing a phenolic resin according to [1] or [2], wherein the sulfonic acid catalyst is trifluoromethanesulfonic acid.

According to the present invention, a phenolic resin that is useful for obtaining a cured product having a high glass transition temperature and high thermal decomposition resistance, has a low melt viscosity and is easy to handle, a method for producing the same, and a heat treatment containing the above phenolic resin. A curable resin composition, a cured product of the thermosetting resin composition, a semiconductor encapsulant containing the thermosetting resin composition, and a semiconductor device containing the cured product are provided.

1 is a GPC chart of a phenolic resin at the time when it was confirmed that BMMB had disappeared after reacting at 130° C. for 2 hours in Example 1. FIG. In Example 1, after confirming that BMMB disappeared, the temperature was raised to 150° C. and the mixture was reacted for 7 hours for neutralization, and the phenolic resin (a-1) obtained by distilling off unreacted compounds. is a GPC chart of 1 is an FD-MS chart of a phenolic resin (a-1) obtained in Example 1. FIG. In Example 2, it is a GPC chart of the phenolic resin when it was confirmed that BMMB disappeared after reacting at 130° C. for 2 hours. In Example 2, after confirming that BMMB disappeared, the temperature was raised to 150 ° C. and the reaction was performed for 7 hours for neutralization, and the phenolic resin (a-2) obtained by distilling off unreacted compounds. is a GPC chart of In Example 3, it is a GPC chart of the phenolic resin when it was confirmed that BMMB disappeared after reacting at 130° C. for 2 hours. In Example 3, after confirming that BMMB disappeared, the phenolic resin (a-3) obtained by heating to 150° C. and reacting for 7 hours for neutralization and distilling off unreacted compounds. is a GPC chart of 1 is a GPC chart of a phenol resin (a-4) obtained in Comparative Example 1. FIG.

Embodiments of the present invention will be described below.
The phenolic resin (a) according to one embodiment of the present invention is a unit represented by the following formula (A) and / or formula (B), that is, a structural site represented by formula (A) and / or formula (B) and the melt viscosity at 150° C. is 50 mPa·s or more and 400 mPa·s or less.
(p2 and p3 in formula (A) and formula (B) may be the same or different and are 0 or 1; q2 and q3 may be the same or different and are 0, 1 or ² ; ^R3 is a methyl group.)

The phenol resin (a) can be represented by the following general formula (1).

(n and m in the general formula (1) are the average values of the repeating units enclosed by [] included in the phenolic resin component, n is 0.10 or more and 4.0 or less, and m is 0.10 n+m is 1 or more, p1, p2, p3 may be the same or different, and is 0 or 1, q1, q2, q3 may be the same or different, 0, 1 or 2, and R ¹ , R ² and R ³ are methyl groups.)

General formula (1) indicates that the phenolic resin component includes units (A) and/or units (B) enclosed in [], and units (A) and units (B ) has not been specified.

From the viewpoint of lowering the melt viscosity of the phenol resin (a), the average value n of the number of units (A) included in the phenol resin component is preferably 0.10 or more and 4.0 or less, and 0.50 or more and 3.0 or less. is more preferable, and 1.0 or more and 2.0 or less is even more preferable. From the same point of view, the average value m of the number of units (B) included in the phenolic resin component is preferably 0.10 or more and 2.0 or less, more preferably 0.15 or more and 1.0 or less, and 0.20 or more and 0 0.50 or less is more preferred.

The upper limit of the total n + m of the average value n of the units (A) and the average value m of the units (B) is preferably 2 or less, and further 1.8 or less, from the viewpoint of the phenol resin (a) having a low melt viscosity. preferable. Its lower limit is 1 or more, preferably 1.5 or more.

From the same point of view, the sum (p1+p2+p3) of p1, p2 and p3 in general formula (1) is preferably 0.10 or more and 1.0 or less, more preferably 0.20 or more and 0.80 or less, and 0.10 or more. 25 or more and 0.60 or less is more preferable.

The average value n of the units (A), the average value m of the units (B), and p1+p2+p3 included in the components constituting the phenol resin (a) of the present embodiment refer to values obtained from the reaction rate of each raw material. The reaction rate of monohydric phenols and dihydric phenols is calculated by analyzing the unreacted portion and obtaining the amount of resin obtained, and formalin (formaldehyde) and the biphenyl compound represented by the general formula (2) described later. The reaction rate is calculated using the charged amount.

The phenolic resin according to one embodiment of the present invention can be produced by the production method described below.
The method for producing a phenolic resin according to the present embodiment comprises a first reaction of reacting resorcinol and formaldehyde, a product of the first reaction, a monohydric phenol, and a biphenyl compound represented by the following general formula (2). and a second reaction in the presence of a sulfonic acid catalyst.

(X in general formula (2) is a methoxy group, a hydroxyl group, or a halogen.)

The first reaction is a step for reacting resorcinol and formaldehyde (formalin) to obtain a product used in the second reaction, and is represented by the following reaction formula.

(o is an integer of 1 or more)

The amounts of resorcinol and formaldehyde used as raw materials and the reaction conditions are appropriately set so that the first reaction proceeds appropriately. The molar ratio (C/D) of formaldehyde (D) to the charged amount of resorcin (C) is preferably 1.0 or more and 3.0 or less, more preferably 1.5 or more and 2.5 or less.
Since the first reaction involves the generation of water, it is preferable to set the reaction conditions such as the reaction temperature in consideration of the appropriate discharge of water out of the system. As the reaction temperature of the first reaction based on the considerations, for example, 70° C. or more and 110° C. or less can be mentioned.

As the reaction solvent for the first reaction, biphenyl compounds represented by the general formula (2), toluene, xylene, mesitylene, ethylbenzene, methyl isobutyl ketone, methyl-n-amyl ketone, methyl isoamyl ketone, methanol, ethanol, 1-propanol, 2-propanol, 1-methoxy-2-propanol, ethylene glycol dimethyl ether, diethylene glycol dimethyl ether and the like. From the viewpoint of improving the production efficiency by reducing the steps required for removing the solvent, it is possible to melt the biphenyl compound represented by the general formula (2) used as the raw material for the second reaction and use it as the solvent for the first reaction. preferable.

The second reaction is a step of reacting the product of the first reaction described above, the monohydric phenols, and the biphenyl compound represented by the general formula (2) described above in the presence of a sulfonic acid catalyst to produce a phenolic resin. is.

The reaction temperature of the second reaction may be a temperature at which the above reaction proceeds appropriately, but from the viewpoint of producing a phenolic resin with a low melt viscosity, it is preferably a high temperature. By raising the reaction temperature of the second reaction, a decomposition reaction of the phenolic resin produced by the second reaction occurs. Due to this decomposition reaction, the average molecular weight of the phenolic resin produced in the second reaction is small, the molecular weight distribution is narrowed, and the melt viscosity of the produced phenolic resin can be lowered. The reaction temperature of the second reaction is preferably 140° C. or higher, more preferably 145° C. or higher, and even more preferably 150° C. or higher, from the viewpoint of producing a phenolic resin having a low melt viscosity.

By performing the second reaction under high temperature conditions of 140 ° C. or higher, for example, the number average molecular weight (Mn) is 500 or more and 700 or less, the weight average molecular weight (Mw) is 700 or more and 1300 or less, and Mw / Mn is A phenolic resin is produced that is between 1.6 and 1.9. In the present invention, the Mn and Mw of the phenolic resin refer to values measured by GPC using the method shown in Examples described later.

From the viewpoint of handleability, the melt viscosity of the resin at 150° C. is generally preferably 50 mPa·s or more and 400 mPa·s or less, more preferably 100 mPa·s or more and 300 mPa·s or less. By conducting the second reaction under high temperature conditions, it is possible to produce a phenolic resin having a viscosity within the above range and good handling properties.

In the second reaction, formaldehyde is produced by the decomposition reaction of the phenolic resin. Bisphenol F is produced by reacting formaldehyde with monohydric phenol used as a raw material for the second reaction. Therefore, the phenol resin produced by the production method of the present embodiment contains bisphenol F.

From the viewpoint of controlling the molecular weight distribution of the phenolic resin produced by the second reaction to obtain a phenolic resin having a low melt viscosity, the content of bisphenol F in the phenolic resin is preferably 1% by mass or more and 15% by mass or less. It is preferably 2% by mass or more and 10% by mass or less. In the present invention, the content of bisphenol F in the phenol resin refers to the area percentage of the peak based on bisphenol F when measured by GPC (gel permeation chromatography) using a differential refractometer.

If the reaction rate of the second reaction becomes too high, a biphenyl compound-based substance such as methanol may be produced all at once, and the reaction solution may spout out. Therefore, the reaction conditions may be changed stepwise or continuously in order to control the reaction rate of the second reaction. For example, the sulfonic acid catalyst may be added in multiple portions to change the catalyst concentration in the reaction solution stepwise, or the reaction temperature may be changed stepwise or continuously. When changing the catalyst concentration and the reaction temperature in the second reaction, either one of them may be changed, or both may be changed at the same time.

For example, the sulfonic acid catalyst may be added in two portions in the second reaction, and the reaction temperature may be changed according to the catalyst concentration. In this case, a phenolic resin is mainly produced by setting the reaction temperature to about 120° C. or more and less than 140° C. under conditions where the concentration of the sulfonic acid catalyst is low. Thereafter, by increasing the concentration of the sulfonic acid catalyst and setting the reaction temperature to about 140° C. or more and less than 160° C., a decomposition reaction of the produced phenol resin can be caused and the molecular weight distribution of the phenol resin can be controlled. .

From the viewpoint of adjusting the reaction that produces the phenolic resin in the second reaction and the reaction that controls the molecular weight distribution of the produced phenolic resin, when the sulfonic acid catalyst is added in two portions, the sulfonic acid added first It is preferred to have more sulfonic acid catalyst added in the second addition than catalyst.

From the viewpoint of adjusting the reaction rate in the second reaction, X in the biphenyl compound represented by general formula (2) is preferably a methoxy group.

Examples of the sulfonic acid catalyst used in the second reaction include trifluoromethanesulfonic acid, methanesulfonic acid, benzenesulfonic acid and the like. Among these, trifluoromethanesulfonic acid, which functions as a catalyst with a small addition amount due to its strong acidity, is preferred. When trifluoromethanesulfonic acid is used as the sulfonic acid catalyst, the amount of trifluoromethanesulfonic acid to be added may be such that the concentration in the reaction solution is, for example, about 50 ppm or more and 200 ppm or less.

Specific examples of monovalent phenols used in the second reaction include unsubstituted monofunctional phenol compounds such as phenol and naphthol, and alkyl-substituted monofunctional phenol compounds such as cresol, dimethylphenol and ethylphenol.

The molar ratio (E/F) of the biphenyl compound (F) to the charged amount of the monohydric phenol (E) used in the second reaction is preferably 2 or more and 6 or less, more preferably 3 or more and 5 or less. Moreover, the molar ratio (E/C) of the monovalent phenol (E) to the resorcinol (C) used in the first reaction is preferably 4 or more and 9 or less, more preferably 5 or more and 7 or less. The molar ratio (F/C) of the biphenyl compound (F) to the resorcinol (C) is preferably 0.5 or more and 2.5 or less, more preferably 1.0 or more and 2.0 or less.

A base is added to the phenol resin produced in the second reaction to neutralize the sulfonic acid catalyst, and then unreacted phenol is distilled off from the reaction solution by distillation under reduced pressure to obtain the phenol resin of the present embodiment. can get. As the base for neutralizing the sulfonic acid catalyst, diazabicycloundecene, which is a strong base, is preferred. Commercial products of diazabicycloundecene include DBU: registered trademark (manufactured by San-Apro Co., Ltd.).
By using a strong acid or a strong base as the sulfonic acid catalyst and the neutralizing base, the effect on the produced phenolic resin is reduced, and a process for removing these is not required.

(Thermosetting resin composition)
A thermosetting resin composition according to one embodiment of the present invention contains the above-described phenolic resin, epoxy resin and curing accelerator.

A known epoxy resin can be used. For example, epoxy of bisphenol A type epoxy resin, bisphenol F type epoxy resin, phenol novolak type epoxy resin, cresol novolak type epoxy resin, biphenyl type epoxy resin, phenol biphenyl aralkyl type epoxy resin, aralkyl resin with xylylene bond such as phenol and naphthol. Dicyclopentadiene-modified phenolic resin epoxidized products, dihydroxynaphthalene-type epoxy resins, glycidyl ether-type epoxy resins such as triphenolmethane-type epoxy resins, glycidyl ester-type epoxy resins, divalent or higher epoxies such as glycidylamine-type epoxy resins epoxy resins having a group. These epoxy resins may be used alone or in combination of two or more.

The blending ratio of the phenolic resin and the epoxy resin in the thermosetting resin composition according to one embodiment of the present invention is equivalent to the hydroxyl group (G) contained in the phenolic resin and the epoxy group (H) contained in the epoxy resin. The ratio (G/H) is preferably in the range of 0.7 or more and 1.3 or less, and particularly preferably in the range of 0.9 or more and 1.1 or less. Although the range of the hydroxyl group equivalent of the phenol resin according to the present embodiment is not particularly limited, an example thereof is a range of 120 g/eq or more and 170 g/eq or less.

The thermosetting resin composition according to one embodiment of the present invention may further contain a curing accelerator. As an example of such a curing accelerator, substances known as curing accelerators for epoxy resins can be used. Examples of such effect accelerators include phosphine compounds such as triphenylphosphine, tributylphosphine, tri(p-methylphenyl)phosphine, tri(nonylphenyl)phosphine, tetraphenylphosphonium tetraphenylborate, tetraphenylphosphonium tetra Phosphonium salts such as naphthoic acid borate, triphenylphosphoniophenolate, and betaine-like organophosphorus compounds such as reaction products of benzoquinone and triphenylphosphine can be mentioned.

The amount of the curing accelerator used is not limited. It should be appropriately set according to the function of the curing accelerator.

The thermosetting resin composition according to one embodiment of the present invention may further contain an inorganic filler. Examples of such inorganic fillers include amorphous silica, crystalline silica, alumina, glass, calcium silicate, gypsum, calcium carbonate, magnesite, clay, talc, mica, magnesia, and barium sulfate. Among them, amorphous silica, crystalline silica and the like are preferable.

In order to increase the amount of filler compounded while maintaining excellent moldability, it is preferable to use a spherical filler with a wide particle size distribution that enables close packing. In that case, 5 to 40% by weight of the small particle size spherical inorganic filler with a particle size of 0.1 to 3 μm and 95 to 60% by weight of the large particle size spherical inorganic filler with a particle size of 5 to 30 μm are mixed. It is preferable to use

When the thermosetting resin composition according to one embodiment of the present invention contains an inorganic filler, the amount of the inorganic filler to be blended is appropriately set according to the type and application of the inorganic filler. As a non-limiting example, the content of the inorganic filler may be 60% by mass to 95% by mass of the entire thermosetting resin composition.

The thermosetting resin composition according to one embodiment of the present invention further contains a solvent, a coupling agent, a release agent, a colorant, a flame retardant, a low stress agent, a thickener, etc. Alternatively, it can be reacted in advance and used. Examples of the coupling agent include silane-based coupling agents such as vinylsilane-based, aminosilane-based and epoxysilane-based coupling agents, and titanium-based coupling agents.

A cured product can be obtained by heating the thermosetting resin composition according to one embodiment of the present invention. Since the cured product according to one embodiment of the present invention contains a phenolic resin designed for the purpose of increasing the glass transition temperature, the cured product has a high glass transition temperature and is excellent in thermal decomposition resistance.

The temperature for curing the thermosetting resin composition according to one embodiment of the present invention is appropriately set according to the composition of the cured product. Non-limiting examples include heating in the temperature range of 160°C to 250°C.

A specific operation for curing is also not limited. For example, the thermosetting resin composition according to one embodiment of the present invention is diluted with a solvent as necessary, the resulting diluted solution is applied to a substrate, dried and cured by heating. A cured product (cured product film) according to one embodiment of the present invention can be obtained by peeling the obtained cured coating film from the substrate. A molding material can be obtained by curing the thermosetting resin composition according to one embodiment of the present invention in a mold. A cured product of the thermosetting resin composition according to one embodiment of the present invention may be used as a binder, may be used as a coating material, and a member containing the cured product may be used as a laminate material.

A cured product obtained by curing the thermosetting resin composition according to one embodiment of the present invention has a high glass transition temperature and excellent thermal decomposition resistance, and is therefore suitable as a member constituting a semiconductor device.

A semiconductor sealing material according to one embodiment of the present invention contains a thermosetting resin composition according to one embodiment of the present invention. For example, by dissolving the thermosetting resin composition according to one embodiment of the present invention in a solvent, a semiconductor encapsulant (varnish) to be applied to a circuit board to form an insulating layer can be obtained.

The obtained semiconductor encapsulant is spread on a support film and then heat-treated to form a film, whereby an adhesive sheet for use as an interlayer insulating material can be obtained. This adhesive sheet can be used as an interlayer insulating material in a multilayer printed wiring board. When the interlayer insulating material according to one embodiment of the present invention is used for semiconductor encapsulation, the thermosetting resin composition preferably contains an inorganic filler as described above.

The prepreg comprises a semi-cured body of the thermosetting resin composition according to one embodiment of the present invention and a fibrous reinforcing member such as glass fiber. This prepreg can be used as an interlayer insulating material in a multilayer printed wiring board. A method for manufacturing a prepreg according to one embodiment of the present invention is not limited. The thermosetting resin composition according to one embodiment of the present invention is made into a varnish by adding a solvent as necessary, impregnated into a fibrous reinforcing member, and subjected to a heat treatment to obtain one embodiment of the present invention. Such a prepreg can be produced.

The embodiments described above are described to facilitate understanding of the present invention, and are not described to limit the present invention. Therefore, each element disclosed in the above embodiment is meant to include all design changes and equivalents that fall within the technical scope of the present invention.

EXAMPLES The present invention will be described in more detail with reference to Examples and the like, but the scope of the present invention is not limited to these Examples and the like.

<GPC analysis conditions>
(1) Equipment used: “HLC-8320 GPC” manufactured by Tosoh Corporation
(2) Columns: "TSKgel superHZ4000" (1 column) + "TSKgel superHZ3000" (1 column) + "TSKgel superHZ2000" (2 columns) + "TSKgel superHZ1000" (1 column) (each of 6.1 columns) manufactured by Tosoh Corporation. 0 mm × 15 cm column is connected)
(3) Solvent: Tetrahydrofuran (4) Flow rate: 0.6 ml/min
(5) Temperature: 40°C
(6) Detector: suggested refractive index (RI) meter (measurement device, Tosoh Corporation "HLC-8320 GPC" built-in RI detector)
(7) Standard material for calibration curve: polystyrene manufactured by Tosoh Corporation, molecular weight 1.90 × E5, 9.64 × E4, 3.79 × E4, 1.81 × E4, 1.02 × E4, 2.63 × E3, 5.0×E2

<Hydroxyl equivalent>
It was measured by the acetylation back titration method. Specifically, a sample was acetylated with pyridine and excess acetic anhydride, and acetic acid produced from acetic anhydride consumed by hydroxyl groups present in the sample was determined by titration with a potassium hydroxide alcohol solution.

<Softening point>
It was measured by the ring and ball method in accordance with JIS-K2207 using an automatic softening point apparatus ("ASP-MGK2" manufactured by Meitec).

<FD-MS analysis conditions>
(1) Equipment: JEOL “JMS-T100GCV”
(2) Cathode voltage: -10 kV
(3) Emitter current: 0mA→35mA (51.2mA/min.)
(4) Measurement mass range: m / z = 10 to 2000

(Example 1)
33.0 g of resorcinol, 106.6 g of 4,4'-bis(methoxymethyl)biphenyl (hereinafter referred to as "BMMB"), oxalic acid 0.5 g and 8.3 g of methanol were charged and heated to 95° C. while dissolving. While paying attention to heat generation, 12.2 g of 37% formalin was added dropwise and reacted at 95° C. for 5 hours. Note that oxalic acid was added to react resorcin and formalin (formaldehyde), and BMMB does not participate in the reaction between resorcin and formalin. Methanol was added to aid dissolution.

Then, 160.0 g of phenol was charged and dissolved. Furthermore, 0.2 g (approximately 60 ppm) of 10% trifluoromethanesulfonic acid methanol solution was added, the temperature was raised to 130° C., and reaction was carried out for 2 hours. Methanol produced by the reaction was discharged out of the system, and it was confirmed that BMMB disappeared. The molecular weight calculated by removing residual phenol was number average molecular weight (Mn) 750, weight average molecular weight (Mw) 1620, and Mw/Mn 2.16. A GPC chart at this point is shown in FIG. After that, 0.3 g (about 100 ppm) of 10% trifluoromethanesulfonic acid methanol solution was added, the temperature was raised to 150° C., reaction was performed for 7 hours, and 0.5 g of 10% DBU methanol solution was added for neutralization. . Unreacted phenol and resorcinol were distilled off under reduced pressure to obtain 172.6 g of phenol resin (a-1) having molecular weights of Mn 610, Mw 1060, and Mw/Mn 1.74. The melt viscosity (ICI viscosity) at 150° C. was 190 mPa·s, the softening point was 77° C., and the hydroxyl equivalent was 149 g/eq. A GPC chart of the phenolic resin (a-1) is shown in FIG. 2, and an FD-MS analysis chart is shown in FIG.

As a result of FD-MS analysis, j = 0, k = 1, peak corresponding to s1 + s3 = 0 in the following general formula (3) (M + = 200), j = 0, k = 1, peak corresponding to s1 + s3 = 1 (M+=216), j=1, k=0, peak corresponding to s1+s2=0-2 (M+=366, 382, 398), peak corresponding to j=1, k=1, s1+s2+s3=0-2 (M+=472, 488, 504), j=2, k=0, peak corresponding to s1+s2=0-2 (M+=638, 654, 670), j=2, k=1, s1+s2+s3=0-2 peaks (M+ = 744, 760, 776) corresponding to were detected.
The phenolic resin obtained from the reaction rate of each raw material had q1, q2 and q3 in general formula (1) of 0 and was represented by the following general formula (3). In general formula (3), average j=1.3, average k=0.4, and average s1+s2+s3=0.26.

(Example 2)
A phenolic resin was synthesized in the same manner as in Example 1, except that the amount of 37% formalin added was changed from 12.2 g to 21.9 g. When the temperature was raised to 130° C. and the reaction was carried out for 2 hours to confirm that the raw material BMMB had disappeared due to the reaction, the molecular weights of the phenolic resin excluding residual phenol were Mn 810, Mw 1930, and Mw/Mn 2.38. . A GPC chart of the phenol resin at this time is shown in FIG. After that, 0.3 g of 10% trifluoromethanesulfonic acid methanol solution was added, the temperature was raised to 150° C., the mixture was reacted for 7 hours, and neutralized with 0.5 g of 10% DBU methanol solution. Unreacted phenol and resorcinol were distilled off under reduced pressure to obtain 188.1 g of phenol resin (a-2) having a molecular weight of Mn 610, Mw 1090 and Mw/Mn 1.79. The phenol resin (a-2) had an ICI viscosity of 200 mPa·s at 150° C., a softening point of 79° C., and a hydroxyl equivalent of 144 g/eq. A GPC chart of the phenolic resin (a-2) is shown in FIG.
The phenol resin obtained from the reaction rate of each raw material was represented by general formula (3). In general formula (3), average j=1.1, average k=0.6, and average s1+s2+s3=0.26.

(Example 3)
44.0 g of resorcin, 94.5 g of BMMB, 0.5 g of oxalic acid, and 11.0 g of methanol were placed in a four-necked 500 mL flask equipped with a nitrogen gas inlet tube, a thermometer, and a stirrer, and the temperature was raised to 95°C while dissolving. did. While paying attention to heat generation, 12.2 g of 37% formalin was added dropwise and reacted at 95° C. for 5 hours. Then, 160.0 g of phenol was charged and dissolved. Furthermore, 0.2 g of a 10% trifluoromethanesulfonic acid methanol solution was added, the temperature was raised to 130° C., and the reaction was allowed to proceed for 2 hours. Methanol produced by the reaction was discharged out of the system, and it was confirmed that BMMB disappeared. The molecular weights of the phenolic resin after removing residual phenol were Mn 700, Mw 1420, and Mw/Mn 2.03. A GPC chart of the phenolic resin at this point is shown in FIG. After that, 0.3 g of 10% trifluoromethanesulfonic acid methanol solution was added, the temperature was raised to 150° C., the mixture was reacted for 7 hours, and neutralized with 0.5 g of 10% DBU methanol solution. Unreacted phenol and resorcinol were distilled off under reduced pressure to obtain 157.4 g of phenol resin (a-3) having a molecular weight of Mn 590, Mw 1000 and Mw/Mn 1.69. The phenol resin (a-3) had an ICI viscosity of 200 mPa·s at 150° C., a softening point of 79° C., and a hydroxyl equivalent of 139 g/eq. A GPC chart of the phenolic resin (a-3) is shown in FIG.
The phenol resin calculated from the reaction rate of each raw material was represented by general formula (3). In general formula (3), average j=1.2, average k=0.5, and average s1+s2+s3=0.37.

(Comparative example 1)
33.0 g of resorcinol, 106.6 g of BMMB, 0.5 g of oxalic acid, and 8.3 g of methanol were placed in a four-necked 500 mL flask equipped with a nitrogen gas inlet tube, a thermometer, and a stirrer, and the temperature was raised to 95°C while dissolving. did. While paying attention to heat generation, 12.2 g of 37% formalin was added dropwise and reacted at 95° C. for 5 hours. Then, 160.0 g of phenol was charged and dissolved. Furthermore, 0.2 g of a 10% trifluoromethanesulfonic acid methanol solution was added, the temperature was raised to 130° C., and the reaction was allowed to proceed for 2 hours. Methanol produced by the reaction was discharged out of the system. 0.2 g of a 10% DBU methanol solution was neutralized, the temperature was raised to 150° C., unreacted phenol and resorcinol were distilled off under reduced pressure, and a phenolic resin ( a-4) 167.6 g was obtained. The phenol resin (a-4) had an ICI viscosity of 580 mPa·s at 150° C., a softening point of 91° C., and a hydroxyl equivalent of 145 g/eq. A GPC chart of the phenolic resin (a-4) is shown in FIG.
The difference between Comparative Example 1 and Example 1 is that 0.3 g of a 10% methanol solution of trifluoromethanesulfonic acid was further added after the temperature was raised to 130° C. and the reaction was performed for 2 hours before neutralization. , the temperature was raised to 150° C. and the reaction was not performed.
The phenol resin obtained from the reaction rate of each raw material was represented by general formula (3). In general formula (3), average j=1.6, average k=0.5, and average s1+s2+s3=0.32.

(Comparative example 2)
A phenolic novolak resin containing a triphenolmethane skeleton (trade name “HE910-10” manufactured by Air Water Inc.) was used as the phenolic resin (a-5).
The phenolic resin (a-5) had a hydroxyl equivalent of 100 g/eq, a softening point of 82°C, and an ICI viscosity at 150°C of 110 mPa·s.

Table 1 shows the resin properties of the phenol resins (a-1 to a-5).

As shown in Table 1, the phenol resins (a-1 to a-3) of Examples 1 to 3 are the phenol resin (a-4) of Comparative Example 1 produced without undergoing the reaction at 150 ° C. It had a lower melt viscosity than This result shows that the melt viscosity of the phenolic resin used in the thermosetting composition can be lowered by performing the second reaction in the presence of the sulfonic acid catalyst under high temperature conditions.

In the GPC charts of the phenolic resins a-1, a-2 and a-3 shown in FIGS. 2, 5 and 7, the GPC chart of the phenolic resin a-4 of Comparative Example 1 shown in FIG. 2 and 8) is larger. This peak is that of bisphenol F, indicating that bisphenol F was produced by the second reaction. This indicates that formaldehyde was produced in the second reaction. Since the formaldehyde added as a raw material disappears once in the first reaction, it can be said that the formaldehyde used for the production of bisphenol F was produced by the decomposition reaction of the phenol resin.
In the GPC charts of the phenolic resin before the reaction at a high temperature of 150° C. shown in FIGS. 1, 4 and 6, no peak of bisphenol F is observed as in FIG. This also supports the fact that the decomposition reaction of the phenolic resin occurred by performing the second reaction under high temperature conditions.
In the GPC charts of FIGS. 2, 5 and 7, the peak area percentages of bisphenol F were 5.6 area %, 7.5 area % and 6.5 area %, respectively.

(Examples 4 to 6, Comparative Examples 3 and 4)
Epoxy resins, phenolic resins of Examples 1-3 or Comparative Examples 1-2, and curing accelerators were used in amounts (parts by weight) shown in Table 2 below, respectively, and pulverized to form Examples 4-6 and Comparative Thermosetting resin compositions of Examples 3 and 4 were obtained. The thermosetting resin composition was melt-mixed and molded at 175°C for 2 minutes, and post-cured (post-treated) at 180°C for 6 hours to obtain a cured product. Table 2 shows the evaluation results of the obtained cured product.

As the epoxy resin, a biphenyl aralkyl epoxy resin represented by the following general formula (4) (manufactured by Nippon Kayaku Co., Ltd., trade name “NC-3000” epoxy equivalent: 275 g / eq) was used, and as a curing accelerator (2-( triphenylphosphonio)phenolate) was used.

(Measurement of glass transition temperature Tg)
The cured films obtained in Examples 4 to 6 and Comparative Examples 3 and 4 were cut (cut out) into predetermined sizes and used as samples for glass transition temperature measurement. Thermal mechanical analysis (TMA) was used to measure the coefficient of linear expansion under the following conditions, and the inflection point of the coefficient of linear expansion was defined as the glass transition temperature Tg.
Measuring instrument: TMA/SS7100 manufactured by Hitachi High-Tech Science Co., Ltd.
Sample length: 6-7mm
Atmosphere: Nitrogen Measurement temperature: 25 to 300°C
Heating rate 10° C./min Measurement mode: Tensile As another method for measuring the glass transition temperature Tg, there is dynamic viscoelasticity measurement (DMA). The value of the glass transition temperature Tg measured by DMA is about 10 to 20° C. higher than the value measured by thermomechanical analysis (TMA).

(Evaluation of long-term heat resistance at 250°C)
About 5 g of each thermosetting resin composition was placed in an aluminum cup, cured under the conditions described above, and weighed. Next, put the sample of the cured product in a hot air dryer at 250 ° C., take it out after 360 hours, measure the weight, calculate the weight reduction rate (%) with respect to the measured value before putting it in the hot air dryer, long-term heat resistance evaluated the sex.

(Measurement of water absorption)
The thermosetting resin composition is cured in the same manner as described above, and a sample of the cured product is placed in a constant temperature and humidity chamber at a temperature of 85 ° C. and a humidity of 85%. The rate of increase (%) in weight with respect to the measured value before placing in a vessel was calculated to determine the water absorption, and the reliability of the cured product used as a semiconductor encapsulating material was evaluated.

As shown in Table 2, the cured products of Examples 4 to 6 using phenolic resins a-1, a-2, and a-3 are higher than the cured product of Comparative Example 3 using phenolic resin a-4. The glass transition temperature Tg was high. From this, by performing the second reaction under high temperature conditions, the melt viscosity of the phenol resin is reduced and the glass transition temperature Tg of the cured product of the thermosetting resin composition containing the phenol resin is increased. I found out.
In addition, the cured products of Examples 4 to 6 had a glass transition temperature Tg equal to or higher than that of the cured product of Comparative Example 4 obtained using a phenolic novolac resin containing a triphenolmethane skeleton, and the weight reduction rate was and low water absorption. From these results, it can be said that the thermosetting resin composition according to the present invention has high reliability and is suitable as a semiconductor sealing material.

Claims (3)

a first reaction of reacting resorcinol and formaldehyde;
a second reaction in which the product of the first reaction, a monohydric phenol, and a biphenyl compound represented by the following general formula (2) are reacted in the presence of a sulfonic acid catalyst;
A method for producing a phenolic resin containing a component having a unit represented by the following formula (A) and/or formula (B) and bisphenol F and having a melt viscosity of 50 mPa·s or more and 400 mPa·s or less at 150°C.
(X in general formula (2) is a methoxy group, a hydroxyl group, or a halogen.)


(p2 and p3 in formula (A) and formula (B) may be the same or different and are 0 or 1; q2 and q3 may be the same or different and are 0, 1 or ² ; R3 is a methyl group. ⁾ The method for producing a phenolic resin according to claim 1, wherein the reaction temperature in the second reaction is 140°C or higher. 3. The method for producing a phenolic resin according to claim 1, wherein the sulfonic acid catalyst is trifluoromethanesulfonic acid.