JPH1160699A - Novel polyalkylphenol resin and its preparation - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a resin containing no formaldehyde of a low molecular- weight or a low dispersion by carrying out melt-polymerization of a phenol monomer in the presence of an alkaline material, a phase transition agent and an oxidizing agent. SOLUTION: One mol of a phenol monomer of formula I is melt-polymerized at 60-180 deg.C in the presence of 5-100 m mol of an alkaline material such as NaOH or the like and 0.1-10 m mol of a phase transition agent such as a chlorotetramethylammonium salt or the like by the introduction of 0.2-1.0 mol of an oxidizing agent such as hydrogen peroxide or the like and optionally 0.01-10 millimol of a catalyst such as copper chloride. The product is refined by a solvent extraction to give a polyalkylphenol resin having a polydispersion index of 1-3 and a number average molecular weight of 300-1,000. The phenol monomer is phenol, ortho-cresol, 3-methylphenol or the like. In the formula, R is a 1-5C alkyl, styryl or a halogen; (h) is 0-4; (n) is 0-4; (k) is 0-3; (l) is 0-4; and (m) is a integer of 1-10.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a novel polyalkylphenol resin and a method for producing the same.

[0002]

2. Description of the Related Art Phenol-novolak-varnish resins and ortho-cresol-novolak-varnish resins are mainly used as phenol resins currently used. Phenol-novolak-varnish resins are particularly used because they can be used in a mixture with many fillers. For example, it is widely used for casting sand frame type for casting, brake felt mainly made of asbestos, impregnated resin for copper beam board, fuse squirrel switch unit, etc. A phenol-novolak-varnish resin is used as a main resin, a curing agent and a filler are mixed, and the mixture is heated and cured to form a molding material having different characteristics. Also, with the development of industrial technology, in the field of electronic materials and the like, the demands for the properties required of the materials used are increasing day by day.

[0003] The phenol-novolak-varnish resin widely used at present is expected to be further improved in heat resistance, hygroscopicity and reactivity, and has been studied. No. 268,956 points out that the phenol-novolak-varnish resin leaves a lot of unreacted free phenol, which is a drawback in use. In addition, Japanese Patent No.
242719 reports that many unreacted free phenols can be distilled off by steam, but the phenol-novolak-
The disadvantage is that the varnish resin decomposes. Furthermore, when phenol-novolak-varnish resin is processed at a high temperature, formaldehyde and phenol released by the decomposition of the resin may be generated, so that many questions are left from the viewpoint of production and environmental conservation in use. ing.

[0004] Recently, with the advancement of science and technology relating to semiconductors, the level of IC lamination technology has increased, and the tendency of lamination on the surface has been increased. Ortho-cresol-novolak-varnish cured using a conventional phenol-novolak-varnish resin. It is difficult for a resin-based material to satisfy the requirements of light, thin, short, and small for today's electronic materials in terms of both heat resistance and moisture absorption resistance.
Japanese Patent Publication No. 198,526 (1983),
No. 2,824 (1988) and the Republic of China (Taiwan) Patent No. 193,206 use a phenol-aldehyde resin synthesized with a different aldehyde as a curing agent, but the above-mentioned high-temperature method is used. There is a problem that aldehydes may be liberated at the time of processing, and the heat resistance and moisture absorption resistance of the cured product are as described above, as described above, of the “light, thin, short, small” required by today's electronic materials. Although it is not suitable for the conditions, the above-mentioned conventional hardening materials are hardly satisfactory particularly in view of low melt viscosity.

[0005]

Means for Solving the Problems The present inventors have conducted studies to solve the above problems, and as a result, have found that a novel polyalkylphenol resin represented by the following general formula (I) exhibits excellent properties. The present invention has been completed.

A first object of the present invention is to provide a novel polyalkylphenol resin represented by the following general formula (I) having a low molecular weight or a small degree of molecular weight dispersion and containing no formaldehyde in a chemical structure.

[0007]

Embedded image Wherein R is the same or different and each represents a C _1-5 alkyl group, styryl group or halogen atom;
K is an integer of 0-3; l is an integer of 0-4; and m is 1
Indicates an integer of 10]

Another object of the present invention is to directly carry out a melt polymerization reaction of at least one kind of phenol monomer represented by the following general formula (II) in the presence of an alkaline substance, a phase transfer agent and an oxidizing agent. It is another object of the present invention to provide a method for producing a polyalkylphenol resin represented by the general formula (I).

[0009]

Embedded image Wherein R is the same or different and each represents a C _1-5 alkyl group, styryl group or halogen atom;
Indicates an integer of

The present invention relates to a novel polyalkylphenol resin represented by the following general formula (I).

Embedded image Wherein R is the same or different and each represents a C _1-5 alkyl group, styryl group or halogen atom;
K is an integer of 0-3; l is an integer of 0-4; and m is 1
Indicates an integer of 10]

The novel polyalkylphenol resin according to the present invention has a low molecular weight and a small molecular weight dispersion.
Moreover, it is a polyalkylphenol resin containing no formaldehyde in its chemical structure.

Since the novel polyalkylphenol resin of the present invention does not contain formaldehyde in its chemical structure, there is no risk of producing formaldehyde which is a highly volatile toxic substance, and it is safe from the viewpoint of environmental protection in production. Furthermore, since novel polyalkyl phenol resin according to the present invention is the benzene ring is bonded strongly by the carbon in the direct ring, conventional phenolic - novolak - methylene seen in varnish resin (-CH ₂ -) weak binding, such as binding Therefore, even in an epoxy resin curing system, when the polyalkylphenol resin of the present invention is used as a curing agent, the glass transition temperature of the cured product is much higher than that of a conventional phenol-novolak-varnish resin used as a curing agent. This is advantageous. In particular, in the present invention, the amount of free alkylphenol remaining in the polyalkylphenol resin can be limited to 1% or less, so that it is conventionally widely used for casting sand frame molds for casting, felts and bakelites for brakes, and the like. Phenol-novolak-varnish resin, and can be used instead.

Further, since the polyalkylphenol resin according to the present invention has structural stability and liquid crystal characteristics of a diphenol structure, its melting point and viscosity are determined by the currently used phenol-novolak-varnish resin. Ortho-cresol-novolak-varnish resin is very low, and furthermore, since there is a hydrophobic group bond in the benzene ring, the volume is smaller than that of the novolak-varnish resin from the overall structural aspect, and the packaging material of electronic materials is It is advantageously used as a curing agent and can improve the conventional problems of viscosity and hygroscopicity.

In the polyalkylphenol represented by the formula (I) of the present invention, the C _1-5 alkyl group represented by R includes a linear or branched C _1-5 alkyl group. Groups, ethyl group, n-propyl group, isopropyl group, n-butyl group, isobutyl group, t-butyl group, amyl group, neoamyl group and the like. The formula of the present invention
In the polyalkylphenol shown in (I), as a halogen atom represented by R, a fluorine atom, a chlorine atom,
Examples thereof include a bromine atom and an iodine atom.

The polyalkylphenol resin according to the present invention has a number average molecular weight (Mn) of 300 to 1,000 and a polydispersity index (PDI) of 1 to 3, preferably 1 to 2. It is.

As a method for producing the polyalkylphenol represented by the formula (I) according to the present invention, specifically, at least one or more phenol monomers represented by the following formula (II) are used:

Embedded image (Wherein, R is the same or different and each represents a C _1-5 alkyl group, styryl group or halogen atom; h represents an integer of 0 to 4) Alkaline substance, directly in the presence of a phase transfer agent and an oxidizing agent It can be obtained by performing a melt polymerization reaction.

Specific examples of the phenol monomer represented by the above formula (II) include phenol, ortho-cresol, meta-cresol, para-cresol, 2-ethylphenol, 2-propylphenol, 4-t-butylphenol, 2-isopropylphenol, 2-bromophenol, 2-chlorophenol, 2-methyl-
5-chlorophenol, 2-t-butyl-5-chlorophenol, 2-styrylphenol, 2-methyl-3-
Bromophenol, 2-ethyl-3-bromophenol, 2-t-butyl-3-bromophenol or a suitable mixture thereof can be mentioned. Among them, phenol, ortho-cresol, 3-methylphenol, 4
-Methylphenol and 2-t-butylphenol are preferred.

In the production method according to the present invention, examples of the alkaline substance used include alkali metal hydroxides, carbonates, and borate. Specifically, for example, sodium hydroxide, potassium hydroxide, carbonate Examples thereof include sodium, potassium carbonate, potassium tetraborate, and sodium tetraborate. The use amount is 5 to 100 mmol, more preferably 10 to 50 mmol, per 1 mol of the phenol monomer. In the production method according to the present invention, a quaternary ammonium salt may be used as a phase transfer agent (or a phase transfer catalyst), and specifically, for example, tetramethylammonium chloride, tetrabutylammonium bromide, benzyl chloride A halogenated tetraalkylammonium salt such as a trimethylammonium salt is used.
The amount of the phenol monomer to be used is 0.
It is 1 to 10 mmol, more preferably 1 to 5 mmol.

In the production method according to the present invention, examples of the oxidizing agent used include hydrogen peroxide, oxygen, and a gas containing oxygen. The amount used is phenol monomer 1
It is 0.2 to 1.0 mole, more preferably 0.25 to 0.75 mole per mole. The oxidizing agent may be added to the reactor at one time, or may be separated according to the required amount and continuously introduced into the reactor.

In the production method according to the present invention, the reaction is 6
The reaction is carried out at a temperature in the range of 0 to 180 ° C, particularly preferably in the range of 90 to 150 ° C. The reaction time is 2 to 10 hours. In the production method according to the present invention, if necessary, a copper compound catalyst may be added, whereby the conversion of the monomer can be increased and the yield can be increased. Examples of the copper compound used for the catalyst include copper chloride, copper bromide, copper acetate, copper sulfate, copper benzoate, copper nitrate, copper chlorate, cuprous chloride and the like. The amount of the copper compound catalyst to be used is 0.01 to 10 mmol, preferably 0.1 to 5 mmol, per 1 mol of the phenol monomer.

In the production method according to the present invention, the product polyalkylphenol resin can be purified by a solvent extraction method. Examples of the solvent to be used include solvents that do not dissolve in water, and specific examples thereof include toluene, methyl ethyl ketone, methyl isobutyl ketone, ethylene glycol and isobutanol.

[0022]

The present invention will be described in more detail with reference to the following examples, but the present invention is not limited to these examples.

Example 1 Ortho-cresol 21 was placed in a 1-liter autoclave.
8 g (about 2 mol), 4.03 g of a 49.6% sodium hydroxide aqueous solution and 0.51 g of tetrabutylammonium bromide (TBAB) as a phase transfer agent were added, and the temperature was raised to 150 ° C. Stirring was continued for about 4 hours while introducing oxygen at a flow rate of 50 cc. Toluene was added and dissolved by adding 1090 g of toluene, and neutralized by adding 37% hydrochloric acid. Deionized water 1
The separated layers were washed three times each with 090 g, and the unreacted ortho-cresol monomer and toluene were distilled off. Further, steam was introduced to distill off the remaining ortho-cresol monomer about 2 hours. As a result, 121.4 g of a polyorthocresol resin represented by the following formula (Ia) was obtained. Table 1 shows the measurement results of the conversion, physical properties, heat resistance temperature and the like.

[0024]

Embedded image

Example 2 Ortho-cresol 21 was placed in an autoclave having a capacity of 1 L.
8 g (about 2 mol), 4.03 g of a 49.6% aqueous sodium hydroxide solution, 0.51 g of tetrabutylammonium chloride (TBAC) as a phase transfer agent, and copper acetate (0.04 g) as a catalyst.
5 g) was added, the temperature was raised to 150 ° C., and stirring was continued for about 4 hours while introducing oxygen at a flow rate of 50 cc per minute.
872 g of methyl ethyl ketone was added and dissolved, and neutralized by adding 37% hydrochloric acid. Further, the separated liquid was washed three times with 872 g of deionized water. Unreacted ortho-cresol monomer and methyl ethyl ketone were distilled off, and the remaining ortho-cresol was distilled off with steam for about 2 hours to obtain 133.4 g of a polyortho-cresol resin represented by the above formula (Ia). . Table 1 shows the measurement results of the conversion, physical properties, and heat-resistant temperature.

Example 3 Ortho-cresol 21 was placed in an autoclave having a capacity of 1 L.
8 g (about 2 mol), 9.712 g of sodium tetraborate, 1.09 g of benzyltrimethylammonium chloride (BTMAC)
After adding 0.1 g of copper acetate and raising the temperature to 150 ° C., the reaction was continued for about 4 hours while gradually introducing oxygen at a flow rate of 100 cc for one minute. The temperature and pressure were reduced, and the product was poured into a 3 L glass vessel, and 1296 g of pure water and 1 part of toluene were added.
296 g was added, and the mixture was neutralized with acetic acid and separated. After washing the organic layer with water three times, toluene and ortho-cresol are distilled off by distillation under reduced pressure, and furthermore, ortho-cresol remaining in the resin at 180 ° C. through steam is distilled off for about 2 hours. 137.1 g of the polyortho-cresol resin indicated under Ia) were obtained. The conversion rate,
Table 1 shows the measurement results of the physical properties and the heat resistant temperature.

Example 4 Ortho-cresol 43 was placed in a 1-liter autoclave.
2 g (3.96 mol), 8.06 g of a 49.6% aqueous sodium hydroxide solution, benzyltrimethylammonium chloride
After adding 1.09 g of (BTMAC) and 0.15 g of copper acetate and raising the temperature to 150 ° C., the reaction was continued for 4 hours while gradually introducing oxygen at a flow rate of 100 cc per minute. The temperature and pressure were reduced, and the product was poured into a glass vessel having a capacity of 3 L, 1296 g of pure water and 1296 g of toluene were added, and the mixture was neutralized with acetic acid and separated. After the organic layer was washed three times with water, toluene and ortho-cresol were distilled off under reduced pressure.
The cresol was distilled off for about 3 hours to obtain 273.9 g of a boron-cresol resin represented by the above formula (Ia). Table 1 shows the measurement results of the conversion, physical properties and heat-resistant temperature.

Example 5 Ortho-cresol 21 was placed in a 1-liter autoclave.
8 g (about 2 mol), sodium tetraborate 11.05 g, benzyltrimethylammonium chloride (BTMAC) 1.09
g and 0.2 g of copper acetate, and the mixture was heated to 150 ° C., and the reaction was continued for about 4 hours while gradually introducing oxygen at a flow rate of 100 cc per minute. After reducing the temperature and pressure,
The product was poured into a 3 L glass pot, and 872 g of pure water was added.
And 872 g of methyl ethyl ketone, and the mixture was neutralized with acetic acid and separated. After the organic layer was washed three times with water, methyl ethyl ketone and ortho-cresol were distilled off under reduced pressure, and steam was introduced.
The cresol was distilled off for about 2 hours to obtain 143.2 g of a polyortho-cresol resin represented by the above formula (Ia). Table 1 shows the measurement results of the conversion, physical properties and heat-resistant temperature.

Example 6 In a 1 L autoclave, 218 g (about 2 mol) of a mixture of meta-cresol and para-cresol (4: 6) were added.
6.64 g of a 9.6% aqueous sodium hydroxide solution, 0.51 g of tetrabutylammonium bromide (TBAB) and 0.05 g of copper acetate were added, the temperature was raised to 150 ° C., and oxygen was supplied at a flow rate of 100 cc per minute. The reaction was continued for 4 hours while passing slowly through. After lowering the temperature and pressure, the product was poured into a 3 L glass vessel, and 1296 g of pure water and 1 part of toluene were added.
Add 296 g, neutralize with acetic acid and separate. 3 organic layers
After washing with water, toluene, meta-cresol and para-cresol were distilled off under reduced pressure, and steam was further passed through for 180 minutes.
The meta-cresol and para-cresol remaining in the resin were distilled off at about 3 ° C. for about 3 hours to obtain 126.7 g of a borocresol resin represented by the following formula (Ib). Table 1 shows the measurement results of the conversion, physical properties and heat-resistant temperature.

[0030]

Embedded image

Example 7 In a 1 L autoclave, 150 g (about 1 mol) of para-tert-butylphenol, 6.64 g of a 49.6% aqueous sodium hydroxide solution, 0.51 g of tetrabutylammonium bromide (TBAB), And 0.05 g of copper acetate, and the mixture was heated to 150 ° C.
The reaction was continued for about 4 hours with slow introduction at a rate of mL. After lowering the temperature and pressure, the product was poured into a 3 L glass kettle, and 450 g of pure water and 450 g of toluene were added.
Next, the mixture was neutralized with acetic acid and separated. The organic layer was washed three times with water, and toluene and para-tert-butylphenol were distilled off under reduced pressure. Further, by passing water vapor at 180 ° C., p-tert-butylphenol remaining in the resin was distilled off for about 3 hours. 89.7 g of the polypara-tert-butylphenol resin shown in (Ic) were obtained. Table 1 shows the measurement results of the conversion, physical properties and heat-resistant temperature.

[0032]

Embedded image

Comparative Example 1 In a glass reactor having a capacity of 3 L, 320 g of phenol (3.
4 mol), 181 g (2.65 mol) of 44% formaldehyde and 2.88 g of oxalic acid were added, and the mixture was heated to 98 to 100 ° C., and the reaction was continued for about 2.5 hours with stirring. Pure water 20
After washing with water at 0 g and leaving it for about 1.5 hours, the water in the upper layer was distilled off under reduced pressure, and after returning to normal pressure, the temperature was raised to 180 ° C.
After distilling with steam for about 3.5 hours, the steam was stopped,
After the remaining water was continuously distilled off under reduced pressure at the same temperature for 1 hour, the content was taken out in a heated state to obtain a phenol / formaldehyde resin [formula (Id)]. Its number average molecular weight
(Mn) is 580, average duplication unit m is 5.37, and PDI
Was 4.24. Softening temperature: 109.6 ° C, ICI
Melt viscosity (150 ° C): 34 poise. Table 1 shows other physical properties and measurement results of the heat resistance temperature.

[0034]

Embedded image

[0035]

[Table 1]

From the results shown in Table 1, it can be seen that the PDI and the residual amount of the phenol monomer of the polyalkylphenol according to the present invention are lower than those of Comparative Example 1, and that they do not contain formaldehyde.

Examples 8 to 12 The polyortho-cresol resin represented by the above formula (Ia) obtained in Examples 1 to 5 was sufficiently homogeneously mixed at room temperature with the components and the weight composition shown below using a mixer. Mixed. The reaction state was analyzed using a differential scanning calorimeter (hereinafter, abbreviated as DSC). At the same time, the gel time (hereinafter abbreviated as GT), the glass transition temperature and the heat resistant temperature of the cured product [thermogravimeter (Thermogravime)
tric Analyzer (hereinafter abbreviated as TGA)). Ortho-cresol-novolak-varnish epoxy resin (Chang-Yu Synthetic Resin Co., Ltd., CNE-200ELD) 64.11 parts by weight Polyorthocresol resin [Formula (Ia)] 34.41 parts by weight Part triphenylphosphine curing accelerator 1.48 parts by weight Table 2 shows the results of the physical property analysis of the obtained product.

Comparative Example 2 The phenol-aldehyde resin (Id) obtained in Comparative Example 1 was sufficiently homogeneously mixed at room temperature with the following components and weight composition using a mixer. The reaction state was analyzed using a differential scanning calorimeter (DSC). At the same time, the gel time, the glass transition temperature of the cured product, the heat resistance temperature, and the like were also measured. Orthocresol-Novolak-Varnish epoxy resin (CNE-200ELD manufactured by Changchun Synthetic Resins Co., Ltd.) 64.11 parts by weight Phenol-aldehyde varnish resin [Formula (Id)] 34.11 parts by weight Triphenyl Phosphine curing accelerator 1.48 parts by weight Table 2 shows the measurement results of physical properties of the obtained product. Table 2
From the results, it was clear that the cured product obtained from the polyalkylphenol of the present invention exhibited a higher glass transition temperature, a lower residual amount of monomer, and a lower PDI than Comparative Example 2. No difference was observed in other physical properties.

[0039]

[Table 2]

Example 13 and Comparative Example 3 The polycresol resin [formula (Ia)] obtained in Example 4 and the phenol-novolak-varnish resin obtained in Comparative Example 1 [formula (I)
b)] was mixed sufficiently in a weight composition shown in Table 3 using a mixer, and was molded (compressed) for 2 minutes in a temperature range of 60 to 80 ° C, and the boiling moisture absorption rate was measured for 24 hours. did. Table 3 shows the results.

[0041]

[Table 3]

From the results shown in Table 3, it was clear that the molded product produced from the polyalkylphenol of the present invention had a lower moisture absorption after boiling for 24 hours than that produced from Comparative Example 1.

Example 14 The polycresol resin of the formula (Ib) obtained in Example 6 was sufficiently uniformly mixed at room temperature using a mixer with the following components by weight. The reaction state was analyzed using a differential scanning calorimeter (DSC). At the same time, the gelation time (GT), the glass transition temperature of the cured product, and the heat resistance temperature were also analyzed. Orthocresol-novolak-varnish epoxy resin (CNE-200ELD, product of Changchun Synthetic Resins Co., Ltd.) 64.11 parts by weight Polycresol resin [Formula (Ib)] 34.41 parts by weight Triphenylphosphine curing accelerator 1.48 parts by weight Table 4 shows the measurement results of physical properties of the obtained product.

Example 15 The polypara-tert-butylphenol resin represented by the formula (Ic) obtained in Example 7 was sufficiently homogeneously mixed at room temperature with a mixer in the following weight composition using a mixer. Was mixed. The reaction state was analyzed using a differential scanning calorimeter (DSC). At the same time, the gel time (GT), the glass transition temperature of the cured product, the heat resistance temperature, and the like were also measured. Ortho-cresol-novolak-varnish epoxy resin (Chang-Yu Synthetic Resin Co., Ltd., CNE-200ELD) 56.29 parts by weight Polypara-tert-butylphenol resin [Formula (Ic)] 42.21 parts by weight triphenyl Phosphine curing accelerator 1.50 parts by weight Table 4 shows the measurement results of physical properties of the obtained product.

[0045]

[Table 4]

Claims (17)

[Claims] 1. A compound of the general formula (I): Wherein R is the same or different and each represents a C _1-5 alkyl group, styryl group or halogen atom; n is an integer of 0-4; k is an integer of 0-3; l is an integer of 0-4; And m is 1 to 1
Which represents an integer of 0]. 2. The polyalkylphenol resin according to claim 1, which has a polydispersity index (PDI) of 1 to 3. 3. A number average molecular weight (Mn) of 300 to 1000.
The polyalkylphenol resin according to claim 1, which is: 4. The polyalkylphenol resin according to claim 2, which has a polydispersity index (PDI) of 1 to 2. 5. At least one kind of the following general formula (I)
I): embedded image [Wherein, R is the same or different and represents a C _1-5 alkyl group, styryl group or halogen atom, and h represents 0 to
A phenol monomer represented by the general formula (I): ## STR3 ## is obtained by a direct melt polymerization reaction in the presence of an alkaline substance, a phase transfer agent and an oxidizing agent. Wherein R is the same or different and each represents a C _1-5 alkyl group, styryl group or halogen atom;
K is an integer of 0-3; l is an integer of 0-4; and m is 1
A polyalkylphenol resin represented by the following formula: 6. The method for producing a polyalkylphenol resin according to claim 5, wherein the melt polymerization reaction temperature is 60 to 180 ° C. 7. The amount of the alkaline substance, phase transfer agent and oxidizing agent used is 5 to 100 mmol, 0.1 to 10 mol, respectively, relative to 1 mol of the phenol monomer represented by the general formula (II).
The method for producing a polyalkylphenol resin according to claim 5, wherein the amount is 0.2 mmol to 10 mmol. 8. The method for producing a polyalkylphenol resin according to claim 5, wherein the alkaline substance is a boric acid compound, a hydroxide or a carbonate of an alkali metal. 9. The method for producing a polyalkylphenol resin according to claim 8, wherein the borate compound is selected from the group consisting of sodium tetraborate and potassium tetraborate. 10. The method for producing a polyalkylphenol resin according to claim 8, wherein the hydroxide of the alkali metal is selected from the group consisting of sodium hydroxide and potassium hydroxide. 11. The method for producing a polyalkylphenol resin according to claim 8, wherein the alkali metal carbonate is selected from the group consisting of sodium carbonate and potassium carbonate. 12. The method for producing a polyalkylphenol resin according to claim 5, wherein the phase transfer agent is a quaternary ammonium salt. 13. The method for producing a polyalkylphenol resin according to claim 12, wherein the quaternary ammonium salt is a quaternary ammonium halide salt. 14. The quaternary ammonium halide salt is selected from the group consisting of tetramethylammonium chloride, tetrabutylammonium bromide, tetrabutylammonium chloride, benzyltrimethylammonium chloride, and benzyltriethylammonium chloride. A method for producing the polyalkylphenol resin according to claim 13. 15. The method for producing a polyalkylphenol resin according to claim 5, wherein the oxidizing agent is hydrogen peroxide, oxygen, or a gas containing oxygen. 16. The method for producing a polyalkylphenol resin according to claim 5, wherein a copper compound catalyst is further added to the reaction system. 17. The copper compound catalyst is selected from the group consisting of copper chloride, copper bromide, copper acetate, copper benzoate, copper sulfate, copper carbonate, copper nitrate, copper chlorate and cuprous chloride. Item 18. The method for producing a polyalkylphenol resin according to Item 16.