JP2010229304A - Phenol resin, process for producing the same, epoxy resin composition including the resin, and cured article thereof - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a phenol resin which exhibits good curing performance with an epoxy resin and produces a cured article having heat resistance and containing a tetrakisphenol ethane skeleton with lower melting viscosity compared with the conventional phenol resin containing a tetrakisphenol ethane skeleton. <P>SOLUTION: The problem is solved by the process for producing a phenol resin which includes reacting phenols, dialdehydes, and a crosslinked compound containing formaldehyde, and the phenol resin obtained by the process. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

The present invention relates to a phenol resin having a low melt viscosity useful for various binders, coating materials, laminated materials, molding materials, and the like, a production method thereof, a curing agent for epoxy resin using the same, and a cured product.
The phenolic resin of the present invention can be used as a raw material for an epoxidized phenolic resin in addition to being used as a curing agent for an epoxy resin such as for a semiconductor encapsulating material and a printed circuit board interlayer insulating material.

  Conventionally, when a phenol resin consisting of phenols and dialdehydes is used as an epoxy resin curing agent, it exhibits good curability with respect to curing with an epoxy resin, and the cured product has excellent heat resistance and moisture resistance. Therefore, it has been widely used as a curing agent for epoxy resins. (See Patent Document 1)

However, the phenol resin using these dialdehydes has a problem that the melt viscosity becomes high. For example, when glyoxal is used, the melt viscosity does not decrease even if a large amount of excess phenol is added to obtain a tetrakisphenolethane skeleton having a strong crystallinity and a high melting point.
As a countermeasure, melt viscosity can be lowered by stopping the reaction in the middle and having a large amount of low-molecular components so that there is no crystallinity. However, since there are many low-molecular components, the glass transition temperature and mechanical properties are low. The problem is not enough. (See Patent Document 2)

When the melt viscosity is high, there is a problem in workability such as requiring high temperature due to low fluidity when used in various applications. In addition, there is a risk that defects may occur in moldability such as poor filling in semiconductor encapsulant applications.
Accordingly, there is a strong demand for a phenol resin containing a tetrakisphenol ethane skeleton having a lower melt viscosity and suitable for handling.

Japanese Patent No. 2747930 JP 2001-48959 A

  The object of the present invention is to exhibit good curability with the epoxy resin, and the cured product has low heat resistance compared to a phenol resin containing a tetrakisphenolethane skeleton of the prior art while the cured product has heat resistance. It is an object of the present invention to provide a phenol resin containing a tetrakisphenolethane skeleton having a viscosity.

  As a result of intensive studies to achieve the above-mentioned object, the present inventor has a low melt viscosity and good curability with an epoxy resin by containing phenols, dialdehydes and a methylene crosslinking material. The present inventors have found that a phenol resin having a cured product excellent in heat resistance and mechanical properties is effective, and reached the present invention.

  That is, the present invention is a phenol characterized by reacting a phenol represented by the following general formula (2) with a crosslinking group compound containing a dialdehyde represented by the following general formula (3) and formaldehyde. It is the manufacturing method of resin, and its phenol resin.

（式中、Ｒはアルキレン基、又はアリール基であり、ｓは０〜２の整数である。また、Ｒ１は水素原子、ヒドロキシル基、炭素数１から６個のアルキル基、又はアリール基であり、ｐは０〜２の整数である。）

(In the formula, R is an alkylene group or an aryl group, and s is an integer of 0 to 2. R1 is a hydrogen atom, a hydroxyl group, an alkyl group having 1 to 6 carbon atoms, or an aryl group. , P is an integer of 0-2.)

Furthermore, it is the manufacturing method of the phenol resin whose dialdehyde is glyoxal and / or glutaraldehyde.
Moreover, it is a phenol resin containing dialdehydes and formaldehyde represented by the general formula (3) as a crosslinking group compound.

The phenolic resin of the present invention has high heat resistance and has a structure containing a methylene crosslinking group in the molecule, so that it exhibits good curability in curability with epoxy resin, and has heat resistance and mechanical properties. While having a lower melt viscosity than a phenolic resin having a tetrakisphenolethane skeleton of the prior art.
In addition to the epoxy resin curing agent, the resin can be used as an epoxy resin.

  Hereinafter, the present invention will be described in detail.

  The phenol resin of this invention is obtained by making it react with the phenols shown by following General formula (2), the dialdehyde shown by following General formula (3), and formaldehyde.

（式中、Ｒはアルキレン基、又はアリール基であり、ｓは０〜２の整数である。また、Ｒ１は水素原子、ヒドロキシル基、炭素数１から６個のアルキル基、又はアリール基であり、ｐは０〜２の整数である。）

(In the formula, R is an alkylene group or an aryl group, and s is an integer of 0 to 2. R1 is a hydrogen atom, a hydroxyl group, an alkyl group having 1 to 6 carbon atoms, or an aryl group. , P is an integer of 0-2.)

The phenols used in the present invention are compounds having one or more hydroxyl groups on the benzene ring as described in the general formula (2). Examples of the phenols, for example, a substituted or unsubstituted phenol, naphthol, bisphenol, and examples of the substituent represented by R ^1, R ^2, and R ³ in the formula (1), a hydroxyl group, carbon atoms 1 -10 linear or branched alkyl groups, substituted or unsubstituted aryl groups, and the like. ^One to three of these substituents may be substituted in R ¹ and R ² . Specific examples include: phenol; cresol, ethylphenol, n-propylphenol, octylphenol, nonylphenol, phenylphenol, monosubstituted phenols; xylenol, methylpropylphenol, dipropylphenol, dibutylphenol, guaiacol, guetol, etc. Substituted phenols; trisubstituted phenols typified by trimethylphenol; naphthols such as naphthol and methylnaphthol; bisphenols such as bisphenol, bisphenol A, and bisphenol F; and dihydric phenols such as resorcin, catechol, and hydroquinone. These phenols may be used alone or in combination of two or more. Preferred phenols are unsubstituted phenol and meta-substituted linear or branched alkylphenols having 1 to 4 carbon atoms in view of the reactivity of the phenols, and more preferably phenol and m- Cresol.

  The dialdehyde used in the present invention is represented by the general formula (3), and specific examples include glyoxal, glutaraldehyde, terephthalaldehyde and the like. These dialdehydes may be used alone or in combination of two or more, but there is no problem, but glyoxal is preferred because of its availability.

  Preferable examples of the methylene crosslinking material used in the present invention include formaldehyde. Furthermore, the form of formaldehyde is not particularly limited, but a formaldehyde aqueous solution and a polymer that decomposes in the presence of an acid such as paraformaldehyde and trioxane to formaldehyde can also be used. A formaldehyde aqueous solution that is easy to handle is preferable, and a commercially available 42% formaldehyde aqueous solution can be used as it is.

  The synthesis catalyst of the present invention can be synthesized by condensation polymerization in the presence of organic acids such as oxalic acid, formic acid, acetic acid, and Friedel-Craft type catalysts such as sulfuric acid, p-toluenesulfonic acid, and diethyl sulfate. .

Specific production conditions for the phenolic resin of the present invention are as follows. It is possible to carry out by a one-stage condensation reaction by adding m-fold moles of methylene crosslinking material simultaneously with phenols to n-fold moles of dialdehydes. Alternatively, there is no problem even if the addition order is shifted.
In these cases, the use ratio of mmol of methylene crosslinking material (formaldehyde) to nmol of dialdehyde is not particularly limited, but the value of m / n may be 0.1 times mol or more. Preferably it is 0.2-10. More preferably, it is 0.3-5, More preferably, it is 0.5-3. If it is less than 0.1, viscosity reduction cannot be achieved, and if it is 10 or more, a problem that the glass transition temperature decreases may occur.

  The phenol to be used is not particularly limited with respect to the total (n + m) mol of n mol of dialdehyde and m mol of methylene crosslinking agent (formaldehyde), but 3 to 20 times mol is preferable. More preferably, it is 4-10 times mole. When the amount is less than 3 moles, crosslinking proceeds, the melt viscosity is high, the fluidity is lowered, and a phenol resin that meets the object of the present invention may not be stably obtained. If it is too much, the glass transition temperature, which is an index of heat resistance, may decrease.

  In the method for producing a phenol resin of the present invention, the desired melt viscosity at 150 ° C. can be achieved by controlling the amounts of phenols, dialdehydes, and methylene crosslinking agents that are raw materials.

  The amount of the synthetic catalyst used in the present invention is 0.001 to 0.5 parts by weight, preferably 0.001 to 0.2 parts by weight, more preferably 0.001 to 0, based on the amount of phenols used. It is preferably used in the range of 1 part by weight. When the amount used is small, the reaction rate is slow, and when the amount used is too large, the reaction proceeds rapidly and it becomes impossible to control the reaction.

  Moreover, there is no restriction | limiting in the addition order of phenols mentioned above, dialdehydes, and a methylene crosslinking material. In other words, it can be added at the same time and can be carried out in a one-stage condensation reaction. It is produced in a two-stage condensation reaction in which phenols and dialdehydes are preliminarily condensed under an acid catalyst, and then methylene cross-linking material is added and condensed. You can also Alternatively, it can be produced by a two-stage condensation reaction in which a phenol and a methylene crosslinking material are subjected to a condensation reaction in advance under an acid catalyst, and then a dialdehyde is added and blended.

  As a form of the resin obtained by reacting under such production conditions, it is assumed that it is a phenol resin as a constituent component represented by the general formula (1).

  In formula, R is an alkylene group or an aryl group, and s is an integer of 0-2. R1, R2 and R3 may be the same or different and are each a hydrogen atom, a hydroxyl group, an alkyl group having 1 to 6 carbon atoms or an aryl group, and p, q and r are each 0-2. Is an integer. M and n represent positive numerical values.

  The phenol resin of the present invention preferably has a melt viscosity at 150 ° C. of 30 to 4000 mPa · s, more preferably 50 to 3000 mPa · s. When the melt viscosity is 30 mPa · s or less, the workability is deteriorated, or the glass transition temperature, which is an index of heat resistance, may be lowered. When it is 4000 mPa · s or more, the melt viscosity is high and the fluidity is lowered. There is a possibility that molding defects such as defects may occur.

  The phenol resin obtained in the present invention can be used as it is as an epoxy resin curing agent for binders, coating materials, laminates, molding materials and the like, or can be made into an epoxy resin by reacting with epichlorohydrin. . Furthermore, it can also be set as the hardened | cured material using these.

  When using the low melt viscosity phenol resin of this invention as a hardening | curing agent for epoxy resins, this phenol resin, an epoxy resin, and a hardening accelerator are mixed, and it is obtained by making it harden | cure in a 100 to 250 degreeC temperature range.

Examples of the epoxy resin include bisphenol A type epoxy resin, bisphenol F type epoxy resin, cresol novolac type epoxy resin, phenol novolac type epoxy resin, triphenolmethane type epoxy resin, biphenyl type epoxy resin and the like glycidyl ether type epoxy resin, glycidyl Examples thereof include an epoxy resin having two or more epoxy groups in the molecule, such as an ester type epoxy resin, a glycidylamine type epoxy resin, and a halogenated epoxy resin. These epoxy resins may be used alone or in combination of two or more.
Preferred epoxy resins include cresol novolac type epoxy resins and biphenyl type epoxy resins.

  As a hardening accelerator, the well-known hardening accelerator for hardening an epoxy resin with a phenol resin can be used. For example, organic phosphine compounds and boron salts thereof, tertiary amines, quaternary ammonium salts, tetraphenyl boron salts of imidazoles and the like can be mentioned, among which triphenylphosphine is preferable from the viewpoint of curability and moisture resistance. . In order to achieve higher fluidity, a heat-latent curing accelerator that exhibits activity upon heat treatment is preferred, and tetraphenylphosphonium derivatives such as tetraphenylphosphonium and tetraphenylborate are preferred.

  Regarding the method of reacting the phenolic resin of the present invention with epichlorohydrin to form an epoxy resin, for example, an excess of epichlorohydrin is added to the phenolic resin, and in the presence of an alkali metal hydroxide such as sodium hydroxide or potassium hydroxide. The method of making it react for about 1 to 10 hours in -150 degreeC, Preferably it is the range of 60-120 degreeC. In this case, the usage-amount of epichlorohydrin is 2-15 times mole with respect to the hydroxyl equivalent of this phenol resin, Preferably it is 2-10 times mole. Moreover, the usage-amount of the alkali metal hydroxide to be used is 0.8-1.2 times mole with respect to the hydroxyl equivalent of this phenol resin, Preferably it is 0.9-1.1 times mole.

  Regarding post-treatment after the reaction, excess epichlorohydrin is distilled off after completion of the reaction, the residue is dissolved in an organic solvent such as methyl isobutyl ketone, filtered, washed with water to remove inorganic salts, and then the organic solvent is distilled off. By leaving, the target epoxy resin can be obtained.

  A new epoxy resin composition can be obtained using the epoxy resin thus obtained and the phenol resin as a curing agent.

  The obtained epoxy resin composition can be used by adding or reacting in advance with an inorganic filler, a release agent, a colorant, a coupling agent, a flame retardant, or the like, if necessary. In particular, when used for semiconductor sealing applications, addition of an inorganic filler is essential. Examples of such inorganic fillers include amorphous silica, crystalline silica, alumina, calcium silicate, calcium carbonate, talc, mica, barium sulfate, etc., and particularly amorphous silica and crystalline silica. Etc. are preferable. Moreover, the compounding ratio of these additives may be the same as the ratio in a known semiconductor sealing epoxy resin composition.

The present invention will be specifically described below with reference to examples. The present invention is not limited to these examples.
Moreover, the evaluation method of the phenol resin in this invention is shown.

(1) 150 ° C. melt viscosity: The melt viscosity of a phenol resin at 150 ° C. was measured using an ICI melt viscometer.
The measuring method of ICI viscosity is as follows.
ICI Cone Plate Viscometer MODEL CV-1S TOA Industrial Co., Ltd.
The ICI cone plate temperature is set to 150 ° C., and a predetermined amount of the sample is weighed.
Place the weighed resin on the plate, press it with a cone from the top, and leave it for 90 seconds. The cone is rotated and its torque value is read as ICI viscosity.
(2) Softening point: Ring and ball softening point measurement based on JIS K 6910 was performed.
(3) Hydroxyl equivalent: Hydroxyl equivalent measurement based on JIS K 0070 was performed.

Detailed examples are shown below.

Example 1 (addition after formaldehyde (F))
In a glass reaction kettle equipped with a stirrer, a condenser, and a nitrogen gas introduction tube, phenol 752.00 g (8.00 mol), 40% aqueous glyoxal solution 97.30 g (0.68 mol), paratoluenesulfonic acid 1. 67 g was charged and reacted at 120 ° C. for 4 hours. Thereafter, 31.77 g (0.45 mol) of 42% formalin aqueous solution was added and reacted at 100 ° C. for 3 hours. After completion of the reaction, the reaction mixture was neutralized and washed with water three times. The oil layer was separated and 214 g of phenol novolac resin was obtained by distilling off unreacted phenol by distillation under reduced pressure.
The obtained phenol novolac resin had a softening point of 116 ° C., an ICI viscosity of 3100 mPa · s at 150 ° C., and a hydroxyl group equivalent of 120 g / eq.

Example 2 (Glyoxal (G) post-addition)
In a glass reaction kettle equipped with a stirrer, a condenser, and a nitrogen gas inlet tube, phenol 752.00 g (8.00 mol), 42% formalin aqueous solution 31.77 g (0.45 mol), paratoluenesulfonic acid 1. 67 g was charged and reacted at 100 ° C. for 3 hours. Thereafter, 97.30 g (0.68 mol) of a 40% aqueous glyoxal solution was added and reacted at 120 ° C. for 4 hours. After completion of the reaction, the reaction mixture was neutralized and washed with water three times. The oil layer was separated, and unreacted phenol was removed by distillation under reduced pressure to obtain 210 g of phenol novolac resin.
The obtained phenol novolac resin had a softening point of 119 ° C., an ICI viscosity at 150 ° C. of 3100 mPa · s, and a hydroxyl group equivalent of 120 g / eq.

Example 3 (glyoxal and formaldehyde batch addition)
In a glass reaction kettle equipped with a stirrer, a condenser, and a nitrogen gas inlet tube, phenol 752.00 g (8.00 mol), 40% glyoxal aqueous solution 97.30 g (0.68 mol), 42% formalin aqueous solution 31. 77 g (0.45 mol) and 1.67 g of paratoluenesulfonic acid were charged, reacted at 100 ° C. for 3 hours, and then reacted at 120 ° C. for 4 hours. After completion of the reaction, the reaction mixture was neutralized and washed with water three times. The oil layer was separated, and unreacted phenol was distilled off by distillation under reduced pressure to obtain 190 g of phenol novolac resin.
The obtained phenol novolac resin had a softening point of 120 ° C., an ICI viscosity of 3900 mPa · s at 150 ° C., and a hydroxyl group equivalent of 120 g / eq.

Example 4 (addition after F)
In a glass reaction kettle equipped with a stirrer, a condenser, and a nitrogen gas introduction tube, phenol 752.00 g (8.00 mol), 40% glyoxal aqueous solution 64.87 g (0.45 mol), paratoluenesulfonic acid 1. 64 g was charged and reacted at 120 ° C. for 4 hours. Thereafter, 47.65 g (0.68 mol) of a 42% formalin aqueous solution was added and reacted at 100 ° C. for 3 hours. After completion of the reaction, the reaction mixture was neutralized and washed with water three times. The oil layer was separated, and unreacted phenol was removed by distillation under reduced pressure to obtain 180 g of phenol novolac resin.
The obtained phenol novolak resin had a softening point of 95 ° C., an ICI viscosity at 150 ° C. of 330 mPa · s, and a hydroxyl group equivalent of 116 g / eq.

Example 5 (post-F addition)
In a glass reaction kettle equipped with a stirrer, a condenser, and a nitrogen gas introduction tube, 752.00 g (8.00 mol) of phenol, 91.49 g (0.63 mol) of 40% aqueous glyoxal solution, paratoluenesulfonic acid 1. 65 g was charged and reacted at 120 ° C. for 4 hours. Thereafter, 35.41 g (0.50 mol) of a 42% formalin aqueous solution was added and reacted at 100 ° C. for 3 hours. After completion of the reaction, the reaction mixture was neutralized and washed with water three times. The oil layer was separated, and unreacted phenol was distilled off by distillation under reduced pressure to obtain 185 g of a phenol novolac resin.
The obtained phenol novolac resin had a softening point of 110 ° C., an ICI viscosity of 2300 mPa · s at 150 ° C., and a hydroxyl group equivalent of 119 g / eq.

Example 6 (post-F addition)
In a glass reaction kettle equipped with a stirrer, a condenser, and a nitrogen gas introduction tube, 752.00 g (8.00 mol) of phenol, 129.73 g (0.90 mol) of 40% aqueous glyoxal solution, 1. 70 g was charged and reacted at 120 ° C. for 4 hours. Thereafter, 15.88 g (0.23 mol) of a 42% formalin aqueous solution was added and reacted at 100 ° C. for 3 hours. After completion of the reaction, the reaction mixture was neutralized and washed with water three times. The oil layer was separated, and unreacted phenol was distilled off by distillation under reduced pressure to obtain 227 g of a phenol novolac resin.
The obtained phenol novolac resin had a softening point of 136 ° C., an ICI viscosity of> 4000 mPa · s at 150 ° C., and a hydroxyl group equivalent of 127 g / eq.

Example 7 (post-F addition)
In a glass reaction kettle equipped with a stirrer, a condenser, and a nitrogen gas introduction tube, phenol 752.00 g (8.00 mol), 40% aqueous glyoxal solution 32.43 g (0.23 mol), paratoluenesulfonic acid 1. 60 g was charged and reacted at 120 ° C. for 4 hours. Thereafter, 63.54 g (0.90 mol) of a 42% formalin aqueous solution was added and reacted at 100 ° C. for 3 hours. After completion of the reaction, the reaction mixture was neutralized and washed with water three times. The oil layer was separated, and unreacted phenol was removed by distillation under reduced pressure to obtain 195 g of a phenol novolac resin.
The obtained phenol novolac resin had a softening point of 68 ° C., an ICI viscosity at 150 ° C. of 40 mPa · s, and a hydroxyl group equivalent of 114 g / eq.

Example 8 (post-F addition)
In a glass reaction kettle equipped with a stirrer, a condenser, and a nitrogen gas introduction tube, 752.00 g (8.00 mol) of phenol, 129.73 g (0.90 mol) of 40% aqueous glyoxal solution, 1. 85 g was charged and reacted at 120 ° C. for 4 hours. Thereafter, 96.58 g (1.35 mol) of a 42% formalin aqueous solution was added and reacted at 100 ° C. for 3 hours. After completion of the reaction, the reaction mixture was neutralized and washed with water three times. The oil layer was separated, and unreacted phenol was removed by distillation under reduced pressure to obtain 366 g of phenol novolac resin.
The obtained phenol novolac resin had a softening point of 111 ° C., an ICI viscosity at 150 ° C. of 1550 mPa · s, and a hydroxyl group equivalent of 113 g / eq.

Example 9 (post-F addition)
In a glass reaction kettle equipped with a stirrer, a condenser, and a nitrogen gas inlet tube, 11128.00 g (12.00 mol) of phenol, 48.65 g (0.34 mol) of 40% aqueous glyoxal solution, and paratoluenesulfonic acid 2. 29 g was charged and reacted at 120 ° C. for 4 hours. Thereafter, 36.22 g (0.51 mol) of a 42% formalin aqueous solution was added and reacted at 100 ° C. for 3 hours. After completion of the reaction, the reaction mixture was neutralized and washed with water three times. The oil layer was separated, and unreacted phenol was distilled off by distillation under reduced pressure to obtain 123 g of phenol novolac resin.
The obtained phenol novolac resin had a softening point of 84 ° C., an ICI viscosity at 150 ° C. of 190 mPa · s, and a hydroxyl group equivalent of 111 g / eq.

Comparative Example 1
In a glass reaction kettle equipped with a stirrer, a condenser and a nitrogen gas introduction tube, 752.00 g (8.00 mol) of phenol, 162.16 g (1.13 mol) of 40% aqueous glyoxal solution, 1. 72 g was charged and reacted at 120 ° C. for 4 hours. After completion of the reaction, the reaction mixture was neutralized and washed with water three times. The oil layer was separated and unreacted phenol was distilled off by distillation under reduced pressure to obtain 228 g of phenol novolac resin.
The obtained phenol novolac resin had a softening point of 161 ° C., an ICI viscosity of> 4000 mPa · s, and a hydroxyl group equivalent of 125 g / eq.

Comparative Example 2
In a glass reaction kettle equipped with a stirrer, a condenser, and a nitrogen gas introduction tube, 800.00 g (8.51 mol) of phenol, 87.52 g (0.61 mol) of 40% aqueous glyoxal solution, 1. 84 g was charged and reacted at 120 ° C. for 4 hours. After completion of the reaction, the reaction mixture was neutralized and washed with water three times. The oil layer was separated and 100 g of phenol novolac resin was obtained by distilling off unreacted phenol by distillation under reduced pressure.
The obtained phenol novolac resin had crystal grains visible, the softening point was 157 ° C., and the ICI viscosity was> 4000 mPa · s.

Comparative Example 3
In a glass reaction kettle equipped with a stirrer, a condenser, and a nitrogen gas inlet tube, 1891.00 g (20.12 mol) of phenol, 144.76 g (1.01 mol) of 40% aqueous glyoxal solution, paratoluenesulfonic acid, 4. 35 g was charged and reacted at 120 ° C. for 4 hours. After completion of the reaction, the reaction mixture was neutralized and washed with water three times. The oil layer was separated, and 150 g of phenol novolac resin was obtained by distilling off unreacted phenol by distillation under reduced pressure.
The obtained phenol novolac resin had crystal grains visible, the softening point was 150 ° C., and the ICI viscosity was> 4000 mPa · s.

Comparative Example 4
In a glass reaction kettle equipped with a stirrer, a condenser and a nitrogen gas introduction tube, phenol 752.00 g (8.00 mol), 42% formalin aqueous solution 79.42 g (1.13 mol), paratoluenesulfonic acid 1. 57 g was charged and reacted at 100 ° C. for 3 hours. After completion of the reaction, the reaction mixture was neutralized and washed with water three times. The oil layer was separated, and unreacted phenol was distilled off by distillation under reduced pressure to obtain 151 g of phenol novolak resin.
The obtained phenol novolac resin was a semisolid resin at room temperature, and had an ICI viscosity of 12 mPa · s and a hydroxyl group equivalent of 104 g / eq.

Comparative Example 5
A glass reaction kettle equipped with a stirrer, condenser, and nitrogen gas inlet tube was charged with 752.00 g (8.00 mol) of phenol, 388.57 g (5.44 mol) of 42% formalin aqueous solution, and 0.90 g of oxalic acid. , And reacted at 100 ° C. for 8 hours. After completion of the reaction, 641 g of phenol novolac resin was obtained by distilling off unreacted phenol by distillation under reduced pressure.
The obtained phenol novolac resin had a softening point of 95 ° C., an ICI viscosity of 670 mPa · s, and a hydroxyl group equivalent of 107 g / eq.

The synthesis conditions of Examples 1 to 9 and Comparative Examples 1 to 5 and the physical property values of each phenol resin are shown in Table 1.

When the phenol resin synthesized under the conditions shown in Table 1 is used as a curing agent, the epoxy resin is a tetramethylbiphenol type epoxy resin of YX-4000 (epoxy equivalent 186 g / eq) manufactured by JER Co., Ltd. Triphenylphosphine (sometimes abbreviated as TPP) was used as an accelerator.

The phenol resin of the present invention and the epoxy resin were blended so that the phenol hydroxyl group equivalent and the epoxy equivalent ratio were 1: 1, and a TPP catalyst was charged. These were heated to 150 ° C, melted and mixed, vacuum degassed, cast into a 180 ° C mold (thickness 4 mm), cured at 180 ° C for 5 hours, and then further 200 ° C for 8 hours. After curing, a molded product was produced.
Test methods for various physical properties of the obtained molded body (cured product) are as follows.

(4) Water absorption: 24 hours boiling method (molded body of 50 mm length x 50 mm width x 4 mm thickness)
(5) Tg: TMA method (Thermal Mechanical Analysis, thermomechanical analysis method) (heating rate 5 ° C./min)
(6) Mechanical strength: Measured according to JIS K 7171 (7) Gel time Charge the phenol resin and the epoxy resin into a test tube so as to have an equivalent of 1: 1, and further charge TPP into the test tube.
A test tube is installed in a gel timer (Toshiba hour meter SFO-304M) set at a temperature of 175 ° C., and stirred using a SUS stir bar at one rotation.
Initially, the viscosity is low and liquid, but after a certain period of time, the viscosity of the resin rapidly increases and becomes a gel. This time is defined as gel time. The faster this time, the better the curability.

  The blending ratio and curing characteristics are summarized in Table 2.

As can be seen from Table 2, the phenol resins obtained in Examples 1 to 9 achieve a low viscosity or a low softening point while maintaining a high glass transition temperature and a low elastic modulus.
Moreover, it turned out that there is almost no difference in the physical property by the addition order of a raw material by Examples 1-3. Comparative Example 1 achieves a high glass transition temperature but has a very high softening point. In Comparative Examples 4 and 5, the softening point and the viscosity are relatively good, but it is understood that characteristics such as the glass transition temperature and the elastic modulus are impaired. In Comparative Examples 2 and 3, it was impossible to produce a cured product due to remarkable crystallization.

  As described above, the phenol resin containing the tetrakisphenolethane skeleton obtained in the present invention can achieve low viscosity and low softening point while maintaining a high glass transition temperature. It can be used as an electronic material.

Claims (11)

A method for producing a phenol resin, comprising reacting a phenol represented by the following general formula (2) with a crosslinking group compound containing a dialdehyde represented by the following general formula (3) and formaldehyde.

(In the formula, R is an alkylene group or an aryl group, and s is an integer of 0 to 2. R1 is a hydrogen atom, a hydroxyl group, an alkyl group having 1 to 6 carbon atoms, or an aryl group. , P is an integer of 0-2.)   The method for producing a phenol resin according to claim 1, wherein the dialdehyde of the general formula (3) is glyoxal and / or glutaraldehyde. The method for producing a phenol resin according to claim 1, wherein the ratio m / n of the ratio of mol of formaldehyde to n mol of dialdehydes of the general formula (3) is 0.1 or more. The method for producing a phenol resin according to any one of claims 1 to 3, wherein the addition order of the dialdehydes of the general formula (3) and the formaldehyde, which are phenols and a crosslinking group compound, is simultaneous or a division reaction. The epoxy resin composition containing the phenol resin and epoxy resin which were obtained with the manufacturing method of any one of Claims 1-4. Hardened | cured material containing the epoxy resin composition of Claim 5. The epoxidized phenol resin which epoxidized the phenol resin obtained by the manufacturing method of any one of Claims 1-4. The epoxy resin composition containing the epoxidized phenol resin of Claim 7, and the phenol resin obtained by the manufacturing method of any one of Claims 1-4. A cured product comprising the epoxy resin composition according to claim 8.   A phenol resin containing a dialdehyde represented by the above general formula (3) and formaldehyde as a crosslinking group compound. The phenol resin according to claim 10, wherein the melt viscosity at 150 ° C is 30 to 4000 mPa · s.