JP6729863B2 - Method for producing novolac type phenol resin, novolac type phenol resin, thermosetting resin composition and cured product - Google Patents

Description

The present invention relates to a method for producing a novolac type phenolic resin, a novolac type phenolic resin, a thermosetting resin composition, and a cured product obtained by curing them.

Phenolic resins are used in various fields due to their heat resistance.
One example is the use as a curing agent for epoxy resins. In that case, it is excellent in heat resistance, adhesion, and electrical insulation, and is a resin composition for printed circuit boards, a resin composition for interlayer insulating materials used for printed circuit boards and copper foil with resin, and a resin composition for sealing materials of electronic parts. It is used in resist inks, conductive pastes, paints, adhesives, and composite materials.
Along with recent technological innovations, further improvements in heat resistance, moisture resistance, flame retardancy, etc. of epoxy resin compositions have been demanded. In particular, when it is used as a material for electronic parts and its surroundings, it is expected that the material will also be required to have flexibility, because the parts to be used are becoming smaller and thinner.

Under such circumstances, for example, one of the means for solving the problems of heat resistance, moisture resistance and flame retardancy is to increase the amount of filler used. By increasing the amount of the filler, it becomes possible to reduce the linear expansion coefficient, the moisture absorption rate, and the flame retardancy of the molded product. On the other hand, however, an increase in the filling amount causes a problem that the fluidity of the compound is lowered and the moldability is deteriorated. Furthermore, increasing the amount of the filler tends to increase the elastic modulus of the molded product. Therefore, the resin component in the composition is required to have a resin skeleton capable of improving fluidity and imparting more flexibility. However, the heat resistance, moisture resistance and flame retardancy of the cured product, and the flexibility of the cured product and the fluidity of the formulation for obtaining the cured product are contradictory properties, and it has been difficult to achieve both at the same time. It was

The novolak type phenol resin (hereinafter also referred to as “novolak resin”) is produced by addition-condensing phenols and aldehydes in the presence of an acidic catalyst. Usually, the molar ratio of aldehydes to 1 mol of phenols is 1.0 mol or less, and the molecular weight of the resin obtained is controlled by adjusting the molar ratio.
In order to reduce the melt viscosity of the novolac resin, it is necessary to reduce the high molecular weight component as much as possible, and this reduces the crosslink density of the cured product, which has the effect of improving the flexibility of the molded product. In order to obtain a novolac resin having a relatively low molecular weight, the molar ratio of aldehydes to 1 mol of phenols must be reduced, in which case a large amount of unreacted phenolic monomer will remain.
Although unreacted phenolic monomers in the novolac resin can be reduced by distillation under reduced pressure, a larger amount of phenolic monomers are removed by distillation as the novolac resin has a lower molar ratio of aldehydes to 1 mol of phenols. Therefore, a decrease in yield cannot be avoided. On the other hand, when the phenolic monomer remains in the novolac resin, the dimensional stability of the molded product is deteriorated and voids are generated. Therefore, the phenolic monomer in the novolac resin is preferably as small as possible.

Patent Document 1 discloses a method for obtaining fluidity of a novolak resin by increasing the content of a dimer component by causing a heterogeneous reaction of phenols and formaldehydes in the presence of a phosphoric acid catalyst. ing. According to this method, although the fluidity of the novolac resin component is improved, since the catalyst is limited to phosphoric acid, aldehydes having a lower reactivity than paraformaldehyde, for example, aliphatic aldehydes such as acetaldehyde and butyraldehyde, benzaldehyde and salicyl are used. Sufficient reactivity cannot be obtained when reacting with an aromatic aldehyde such as an aldehyde.
In Patent Document 2, a novolak type phenol is obtained by reacting biomass containing an alkyl chain unsaturated bond with phenols under strong acidity to obtain a biomass derivative, and then reacting the biomass derivative with an aldehyde source. A technique of obtaining a resin and thereby imparting flexibility and heat resistance to a cured product is disclosed. According to this method, the flexibility of the cured product is improved by the introduction of the alkyl chain skeleton, but since a strong acid is used during the resin manufacturing process, it is necessary to use a manufacturing facility from the viewpoint of controlling reaction vessel corrosion and reaction heat generation. There will be restrictions. In addition, since ionic impurities are likely to remain, there are restrictions on the applications, which is not practical.

JP, 2007-126683, A JP, 2013-209439, A

The present invention has been made based on the above circumstances, the fluidity of the novolak resin is improved, while the flexibility of the cured product of the resin composition using the novolac resin is improved, and also moisture resistance is imparted. It is an object of the present invention to provide a method for producing a novolac resin that can be used.

That is, the present invention is shown in the following [1] to [11].
[1] A phenol and a saturated aliphatic aldehyde having 6 to 20 carbon atoms are represented by the following general formula (1)
B-(OR) ₃ (1)
(In the formula, each of three R's independently represents a hydrogen atom or an alkyl group having 1 to 10 carbon atoms.) and an acid having a pKa at 25° C. of 5.0 or less. A method for producing a novolac-type phenol resin, which comprises reacting in the presence of
[2] The method for producing a novolac type phenolic resin according to [1], wherein an aromatic aldehyde is reacted in addition to the phenols and the saturated aliphatic aldehyde.
[3] The method for producing a novolac phenolic resin according to [2], wherein the aromatic aldehyde is represented by the general formula (2).

(In the formula, A represents a residue obtained by removing a+1 hydrogen atoms from a monocyclic or polycyclic aromatic hydrocarbon, and R ¹ is each independently an alkyl group having 1 to 6 carbon atoms, a hydroxy group, or a carbon atom. Represents an alkoxy group of formulas 1 to 6 or a halogen atom, and a is an integer of 0 to 3.)
[4] The novolac type phenol according to any one of [1] to [3], wherein the total number of moles of all aldehydes is reacted in a molar ratio of 0.3 to 1 mole with respect to a total of 1 mole of the phenols. Resin manufacturing method.
[5] The novolac-type phenol resin according to any one of [1] to [4], wherein the saturated aliphatic aldehyde is one or more compounds selected from hexyl aldehyde, octyl aldehyde, and 2-methyl valeraldehyde. Production method.
[6] The method for producing a novolac phenolic resin according to any one of [2] to [4], wherein the aromatic aldehyde is one or more compounds selected from benzaldehyde and salicylaldehyde.
[7] The method for producing a novolac phenolic resin according to any one of [1] to [6], wherein the boron compound is boric acid.
[8] A novolac-type phenol resin produced by the method according to any one of [1] to [7].
[9] A thermosetting resin composition containing the novolac-type phenol resin and the epoxy resin according to [8].
[10] The thermosetting resin composition according to [9], which further contains a filler.
[11] A cured product obtained by curing the thermosetting resin composition according to [9] or [10].

According to the present invention, it is possible to provide a method for producing a novolak resin, which improves the fluidity of the novolac resin, improves flexibility of a cured product of a resin composition using the novolac resin, and also imparts moisture resistance. You can

3 is a GPC chart of a novolac resin A in Example 1. 9 is a GPC chart of a novolak resin I in Example 9. 6 is a GPC chart of a novolac resin J in Comparative Example 1.

Hereinafter, the present invention will be described in detail. As described above, the novolac type phenol resin is also referred to as “novolak resin” hereinafter.

<Method of manufacturing novolac resin>
The method for producing a novolac-type phenol resin of the present invention comprises the following general formula (1) in which phenols and a saturated aliphatic aldehyde having 6 to 20 carbon atoms are used.
B-(OR) ₃ (1)
(In the formula, each of three R's independently represents a hydrogen atom or an alkyl group having 1 to 10 carbon atoms.) and an acid having a pKa at 25° C. of 5.0 or less. It is a method of reacting in the presence of.

Furthermore, in the method for producing a novolac resin of the present invention, an aromatic aldehyde may be reacted in addition to the phenols and the saturated aliphatic aldehyde.

In addition, in the method for producing a novolac resin of the present invention, it is preferable to use the aromatic aldehyde represented by the general formula (2).

(In the formula, A represents a residue obtained by removing a+1 hydrogen atoms from a monocyclic or polycyclic aromatic hydrocarbon, and R ^1's each independently represent an alkyl group having 1 to 6 carbon atoms, a hydroxy group, or a carbon atom. Represents an alkoxy group of formulas 1 to 6 or a halogen atom, and a is an integer of 0 to 3.)

Next, each component used in the method for producing the novolac resin and the reaction conditions will be described in detail below.

〔Phenols〕
As the above-mentioned phenols used for producing the novolac resin, those used for producing a general phenol resin can be used. Phenols refer to compounds having a phenol skeleton, and include, in addition to phenol, compounds in which one or more hydrogen atoms of the aromatic ring of phenol are substituted with an alkyl group, a cycloalkyl group, or an aryl group. Specifically, phenol, cresol, ethylphenol, xylenol, butylphenol, octylphenol, nonylphenol, phenylphenol, cyclohexylphenol, trimethylphenol, bisphenol A, catechol, resorcinol, hydroquinone, naphthol, pyrogallol, etc., alone or in combination of two or more. Can be used. Of these, it is preferable to use phenol or cresol because of its high versatility and easy availability of raw materials.

[Aliphatic aldehyde]
The saturated aliphatic aldehyde used for producing the novolac resin is a saturated aliphatic aldehyde having 6 to 20 carbon atoms, preferably a saturated aliphatic aldehyde having 6 to 12 carbon atoms, and more preferably the number of carbon atoms. 6 to 10 saturated aliphatic aldehydes.
Here, a saturated aliphatic aldehyde having 6 to 10 carbon atoms is referred to as a lower aldehyde, and a saturated aliphatic aldehyde having 11 to 20 carbon atoms is referred to as a higher aldehyde, both of which have a linear branch. Some of them are included.

Specific examples of the saturated aliphatic aldehyde used for producing the novolac resin include valeraldehyde, hexylaldehyde, heptylaldehyde, octylaldehyde, nonylaldehyde, decylaldehyde, undecylaldehyde, dodecylaldehyde, tridecylaldehyde, tetra. Decylaldehyde, pentadecylaldehyde, glyoxal, glyoxylic acid, glutaraldehyde, 2-ethylhexanal, 2-methylvaleraldehyde, isobutyraldehyde, 2-methylbutyraldehyde, 3-methylbutyraldehyde, 3-(methylthio)-propionaldehyde, etc. Can be used alone or in admixture of two or more. Of these, hexyl aldehyde, 2-methyl valeraldehyde, and octyl aldehyde are preferably used from the viewpoints of raw material availability, reaction easiness, and addition of curability.

[Aromatic aldehyde]
The aromatic aldehyde that may be used for producing the novolac resin is a compound containing an aromatic group and an aldehyde group.

Specifically, the aromatic aldehyde represented by the general formula (2) is preferable.

(In the formula, A represents a residue obtained by removing a+1 hydrogen atoms from a monocyclic or polycyclic aromatic hydrocarbon, and a R ^1s are each independently an alkyl group having 1 to 6 carbon atoms or a hydroxy group. Represents an alkoxy group having 1 to 6 carbon atoms or a halogen atom, and a is an integer of 0 to 3.) The alkyl group having 1 to 6 carbon atoms of R ¹ is preferably 1 carbon atom. Is an alkyl group having 4 to 4, more preferably an alkyl group having 1 to 3 carbon atoms. Specifically, a methyl group, an ethyl group, an n-propyl group, an isopropyl group and the like can be mentioned. The alkoxy group having 1 to 6 carbon atoms is preferably an alkoxy group having 1 to 4 carbon atoms, and more preferably an alkoxy group having 1 to 3 carbon atoms. Specific examples thereof include a methoxy group, an ethoxy group, a propoxy group and the like. Examples of the halogen atom include a fluorine atom, a chlorine atom, a bromine atom and an iodine atom, and a fluorine atom is preferable.
Specific examples of A include a residue obtained by removing a+1 hydrogen atoms from an aromatic hydrocarbon such as a benzene ring, a naphthalene ring, or an anthracene ring.

Specific examples of the aromatic aldehyde include benzaldehyde, salicylaldehyde, dihydroxybenzaldehyde, methylbenzaldehyde, dimethylbenzaldehyde, trimethylbenzaldehyde, ethylbenzaldehyde, propylbenzaldehyde, butylbenzaldehyde, dibutylbenzaldehyde, methoxybenzaldehyde, dimethoxybenzaldehyde, cuminaldehyde and penta. Methylbenzaldehyde, hydroxymethylbenzaldehyde, phenoxybenzaldehyde, phenylbenzaldehyde, phthalaldehyde, chlorobenzaldehyde, dichlorobenzaldehyde, trichlorobenzaldehyde, tetrachlorobenzaldehyde, bromobenzaldehyde, dibromobenzaldehyde, tribromobenzaldehyde, tetrabromobenzaldehyde, fluorobenzaldehyde, difluorobenzaldehyde, Trifluorobenzaldehyde, tetrafluorobenzaldehyde, iodobenzaldehyde, diiodobenzaldehyde, triiodobenzaldehyde, tetraiodobenzaldehyde, naphthaldehyde, naphthalenedialdehyde, hydroxynaphthylaldehyde, anthracenecarboxaldehyde, pyrenecarboxaldehyde, cyanobenzaldehyde, biphenyldicarboxaldehyde, Etc. can be used alone or in combination of two or more. Of these, benzaldehyde and salicylaldehyde are preferably used from the viewpoint of availability of raw materials and easiness of reaction.

[Molar ratio of total aldehydes to phenols]
Here, "total aldehydes" is used when two or more saturated aliphatic aldehydes are used, or when one or more saturated aliphatic aldehydes and one or more aromatic aldehydes are used in combination. Refers to all aldehydes.

The total molar amount of total aldehydes is preferably 0.3 to 1.0 mol, more preferably 0.4 to 0.8 mol, and further preferably 0.5 with respect to 1 mol of the total amount of the phenols. It is preferably used in a proportion of about 0.7 mol.
When the total molar amount of the total aldehydes is within the above range with respect to the total amount of 1 mol of the phenols, the residual phenols can be maintained in an appropriate amount, and the yield of the novolak resin is reduced. Is suppressed, and the dimensional stability of the molded product using the novolac resin is reduced, and the occurrence of voids is suppressed.
When one or more saturated aliphatic aldehydes and one or more aromatic aldehydes are used in combination, the molar ratio of the two is preferably 8:2 to 3:7, more preferably 7:3 to 4:6, and It is preferably 6:4 to 4:6. Within the above range, the effect of imparting fluidity, flexibility and moisture resistance by using a saturated aliphatic aldehyde and heat resistance by using an aromatic aldehyde can be sufficiently exhibited.

[Boron compound]
The boron compound used in the production of the novolac resin has the following formula (1):
B-(OR) ₃ (1)
(In the formula, each of the three R's independently represents a hydrogen atom or an alkyl group having 1 to 10 carbon atoms).
When R is an alkyl group having 1 to 10 carbon atoms, the alkyl group having 1 to 10 carbon atoms may be linear or branched, and may be methyl group, ethyl group, propyl group, isopropyl group, butyl group. , Isobutyl group, sec-butyl group, tert-butyl group, pentyl group, isopentyl group, sec-pentyl group, tert-pentyl group, neopentyl group, hexyl group, isohexyl group, heptyl group, octyl group, decyl group, etc. Are listed.
Specific examples of the boron compound represented by the formula (1) include boric acid, trimethyl borate, triethyl borate, triisopropyl borate, tributyl borate, etc., which are used alone or in combination of two or more. And boric acid is more preferable.

〔acid〕
The acid used for producing the novolac resin is an acid having a pKa of 5.0 or less at 25° C., and such an acid may be any acid used for producing a general novolac resin, Examples thereof include hydrochloric acid, nitric acid, sulfuric acid, phosphoric acid, p-toluenesulfonic acid, oxalic acid, etc., which may be used alone or in combination of two or more. By using an acid having a pKa of 5.0 or less at 25° C. as a catalyst, a novolac resin having the properties described below can be obtained. Considering the corrosion to the reaction equipment and the yield of the novolak resin, an acid having a pKa of 0.0 to 4.0 is preferable, and for example, oxalic acid (pK _a1 =1.27, pK _a2 =4.27), Examples thereof include phosphoric acid (pK _a1 =2.12), salicylic acid (pKa =2.97), tartaric acid (pK _a1 =3.2), and oxalic acid is more preferable. When the acid is a polybasic acid, it can be applied as long as it has a pK _a1 of 5.0 or less.
Further, in the method for producing a novolac resin of the present invention, although the reason is not clear, it is presumed that by using the above boron compound and an acid together, a sufficient catalytic action for proceeding the reaction can be obtained.

The total amount of the boron compound used is 0.05 to 10 parts by mass, preferably 0.05 to 5 parts by mass, and more preferably 0.1 to 2.5 parts by mass, relative to 100 parts by mass of phenols. It is preferable to use it in a ratio of.
The amount of the acid used is such that the total amount thereof is 0.05 to 10 parts by mass, preferably 0.05 to 5 parts by mass, and more preferably 0.1 to 2.5 parts by mass with respect to 100 parts by mass of phenols. It is preferably used in a ratio.
Furthermore, the total amount of the boron compound and the acid used is 0.1 to 20 parts by mass, preferably 0.1 to 10 parts by mass, and more preferably 0.2, with respect to 100 parts by mass of phenols. It is preferably used in a proportion of from 5 to 5 parts by mass. When the total amount of the boron compound and the acid used is 0.1 parts by mass or more and 20 parts by mass or less, a sufficient effect as a catalyst can be obtained, and a phenomenon that the molecular weight increases during synthesis (decomposition It is possible to obtain the novolac resin described later by suppressing the arrangement).

(Preparation method)
The method of reacting phenols and aldehydes is not particularly limited, for example, a method of charging phenols, total aldehydes, an acid catalyst in a batch and reacting, or charging phenols and an acid catalyst at a predetermined reaction temperature. The method of adding aldehydes can be mentioned. In the latter case, the addition method may be such that one kind is added in order or a plurality of aldehydes are mixed in advance and then added.

(Reaction conditions during manufacturing)
At this time, the reaction temperature is preferably in the range of 30 to 130°C, preferably 50 to 100°C, more preferably 60 to 80°C.
When the reaction temperature is 30° C. or higher and 130° C. or lower, the reaction is performed at an appropriate reaction rate, unreacted phenols are less likely to remain, and the production of the high molecular weight component novolac resin is suppressed.
The reaction time is not particularly limited and may be adjusted depending on the amounts of aldehydes and acid catalysts and the reaction temperature. For example, by reacting for 6 to 10 hours, unreacted phenols are less likely to remain, and the production of the high molecular weight component novolak resin is suppressed.

〔Organic solvent〕
It is also possible to use an organic solvent in the reaction during production.
Examples of such an organic solvent include alcohols such as propyl alcohol and butanol, glycols such as ethylene glycol and propylene glycol, ethylene glycol monomethyl ether, ethylene glycol monoethyl ether, propylene glycol monomethyl ether, propylene glycol monoethyl ether and butylene. Glycol monomethyl ether, butylene glycol monoethyl ether, butylene glycol monopropyl ether and other glycol ethers, methyl ethyl ketone, methyl isobutyl ketone and other ketones, propyl acetate, butyl acetate, ethyl lactate, ethylene glycol monomethyl ether acetate, propylene glycol monomethyl ether Esters such as acetate and ethers such as 1,4-dioxane can be used alone or in combination of two or more kinds.
The organic solvent may be used in an amount of 0 to 1,000 parts by mass, preferably 10 to 100 parts by mass, and more preferably 20 to 50 parts by mass with respect to 100 parts by mass of phenols.
After the reaction, the condensed water may be removed by distillation, or the residual catalyst may be removed by washing with water if necessary.
Further, unreacted phenols and unreacted aldehydes may be removed by performing vacuum distillation or steam distillation.

<Novolak resin>
The novolak resin of the present invention is obtained by the above-mentioned manufacturing method.
The novolac resin is represented by, for example, the following general formula (3).

(In the formula, R ² and R ³ each independently represent any of an alkyl group having 1 to 12 carbon atoms, a hydroxy group, and an alkoxy group having 1 to 12 carbon atoms, and R ⁴ has 5 to 19 carbon atoms. Represents an alkyl group (including those having a side chain), b to c are each independently an integer of 0 to 3, and n is an integer of 1 to 10.)

Furthermore, the novolak resin of the present invention in which a part of the aliphatic aldehyde having 6 to 20 carbon atoms is replaced with an aromatic aldehyde is represented by, for example, the following general formula (4).
(In the formula, A represents a residue obtained by removing a+1 hydrogen atoms from a monocyclic or polycyclic aromatic hydrocarbon, and R ^1's each independently represent an alkyl group having 1 to 6 carbon atoms, a hydroxy group, or a carbon atom. Represents an alkoxy group of formulas 1 to 6 or a halogen atom, and a is an integer of 0 to 3.
Further, R ² , R ^{3 and} R ⁵ each independently represent any of an alkyl group having 1 to 12 carbon atoms, a hydroxy group and an alkoxy group having 1 to 12 carbon atoms, and R ^{4 has} 5 to 5 carbon atoms. It represents 19 alkyl groups (including those having a side chain), a to d are each independently an integer of 0 to 3, and n and m are each independently an integer of 1 to 10. However, the units of n and m may be connected alternately or randomly. )

<Thermosetting resin composition>
The thermosetting resin composition of the present invention contains a novolac resin and an epoxy resin.
[Novolak resin]
The novolac resin is preferably a novolac resin obtained by the method for producing a novolac resin described above, or a novolac resin having the structure described above.

〔Epoxy resin〕
The epoxy resin used in the present invention is not particularly limited, and known epoxy resins can be used. Specific examples of the epoxy resin include bisphenol A type epoxy resin, bisphenol F type epoxy resin, bisphenol S type epoxy resin, bisphenol AD type epoxy resin, resorcinol type epoxy resin, hydroquinone type epoxy resin, catechol type epoxy resin, dihydroxynaphthalene type. Epoxy resins, biphenyl type epoxy resins, epoxy resins derived from divalent phenols such as tetramethylbiphenyl type epoxy resins, phenol novolac type epoxy resins, cresol novolac type epoxy resins, triphenylmethane type epoxy resins, tetraphenylethane Type epoxy resin, dicyclopentadiene-phenol modified epoxy resin, phenol aralkyl type epoxy resin, biphenyl aralkyl type epoxy resin, naphthol novolac type epoxy resin, naphthol aralkyl type epoxy resin, naphthol-phenol co-condensed novolac type epoxy resin, naphthol- Epoxy resin derived from trivalent or higher phenols such as cresol co-condensed novolac type epoxy resin, aromatic hydrocarbon formaldehyde resin modified phenol resin type epoxy resin, biphenyl modified novolac type epoxy resin, epoxy modified with organic phosphorus compound Resin etc. are mentioned. Further, these epoxy resins may be used alone or in combination of two or more kinds. Preferred are triphenylmethane type epoxy resin, cresol novolac type epoxy resin, and biphenylaralkyl type epoxy resin.

[Mixing ratio of epoxy resin and novolac resin]
The mixing ratio of the epoxy resin and the novolac resin is such that the hydroxyl equivalent of the novolac resin is preferably in the range of 0.6 to 1.2, more preferably 0.7 to 1.1 with respect to the epoxy equivalent of 1.0 of the epoxy resin. Range, even more preferably 1.0.
By setting the mixing ratio of the epoxy resin and the novolac resin within the above range, the epoxy groups of the epoxy resin and the hydroxyl groups of the novolac resin react with each other, whereby the performance of the resin is sufficiently exerted on the cured product. Has the advantage.

<Curing accelerator>
A curing accelerator may be appropriately used in the thermosetting resin composition obtained by the present invention for the purpose of accelerating the curing reaction.
Examples of such curing accelerators include imidazole, organic phosphorus compounds, secondary and tertiary amines, organic acid metal salts such as tin octylate, Lewis acids, amine complex salts, and the like. Alternatively, two or more kinds can be used in combination.
Among the above, as the imidazole compound, imidazole, 2-methylimidazole, 2-ethylimidazole, 2-ethyl-4-methylimidazole, 2-phenylimidazole, 2-undecylimidazole, 1-benzyl-2-methylimidazole. , 2-heptadecylimidazole, 4,5-diphenylimidazole, 2-methylimidazoline, 2-phenylimidazoline, 2-undecylimidazoline, 2-heptadecylimidazoline, 2-isopropylimidazole, 2,4-dimethylimidazole, 2- Examples thereof include phenyl-4-methylimidazole, 2-ethylimidazoline, 2-isopropylimidazoline, 2,4-dimethylimidazoline, 2-phenyl-4-methylimidazoline and the like.
These imidazole compounds may be masked with a masking agent.
Examples of the masking agent include acrylonitrile, phenylene diisocyanate, toluidine isocyanate, naphthalene diisocyanate, methylene bisphenyl isocyanate, melamine acrylate and the like.
Examples of the organic phosphorus compound include ethylphosphine, propylphosphine, butylphosphine, phenylphosphine, trimethylphosphine, triethylphosphine, tributylphosphine, trioctylphosphine, triphenylphosphine, tricyclohexylphosphine, triphenylphosphine/triphenylborane complex, and tetraphenylphosphine. Examples include phenylphosphonium tetraphenylborate.
Examples of the secondary amine compound include morpholine, piperidine, pyrrolidine, dimethylamine, diethylamine, dipropylamine, diisopropylamine, dibutylamine, dibenzylamine, dicyclohexylamine, N-alkylarylamine, piperazine, diallylamine, thiazoline, thiol. Examples include morpholine.
Examples of the tertiary amine compound include benzyldimethylamine, 2-(dimethylaminomethyl)phenol, and 2,4,6-tris(diaminomethyl)phenol.

[Other compounding agents]
In addition, the thermosetting resin composition of the present invention may optionally contain various fillers, thermosetting resins and thermoplastic resins used as modifiers, pigments, silane coupling agents, release agents, and the like. The compounding agent can be added depending on the purpose.
Of these, examples of the filler include fused silica, crystalline silica, alumina, zircon, calcium silicate, calcium carbonate, silicon carbide, silicon nitride, boron nitride, zirconia, fosterite, steatite, spinel, titania, and aluminum hydroxide. Inorganic fillers such as magnesium hydroxide. The fused silica can be used in either a crushed form or a spherical form, but in order to increase the content of the fused silica in the thermoplastic resin composition and suppress the increase in the melt viscosity of the molding material, the spherical form is mainly used. It is more preferable to use Furthermore, in order to increase the content of spherical silica in the thermoplastic resin composition, it is preferable to appropriately adjust the particle size distribution of spherical silica. The content of the filler, depending on the application and desired characteristics, the desirable range varies, for example, when used in semiconductor encapsulation applications, higher is preferable in view of the coefficient of linear expansion and flame retardancy, the heat of the present invention The amount is preferably 65% by mass or more, and particularly preferably about 80 to 90% by mass, based on the total amount of the curable resin composition. When used for applications such as a conductive paste or a conductive film, a conductive filler such as silver powder or copper powder can be used.

As the thermosetting and thermoplastic resins used as the modifier, various known ones can all be used, and for example, phenoxy resin, polyamide resin, polyimide resin, polyetherimide resin, polyether sulfone resin, polyphenylene ether. Resins, polyphenylene sulfide resins, polyester resins, polystyrene resins, polyethylene terephthalate resins and the like can be used, if necessary, within a range that does not impair the effects of the present invention.
Examples of the silane coupling agent include silane coupling agents such as aminosilane-based compounds, vinylsilane-based compounds, styrene-based silane compounds, and methacrylsilane-based compounds.
Further, examples of the releasing agent include stearic acid, zinc stearate, calcium stearate, aluminum stearate, magnesium stearate, and carnauba wax.

Hereinafter, the present invention will be described in more detail, but the present invention is not limited thereto.
(Example 1)
A flask equipped with a cooling tube and a stirrer was charged with 100 g (1.06 mol) of phenol, 94.8 g (0.74 mol) of octyl aldehyde, 2 g of boric acid, and 2 g of oxalic acid (pKa=1.04) at 120°C. And reacted for 6 hours. Then, 100 g of pure water was washed 4 times to remove the catalyst and unreacted phenol. Next, the distillate was removed under reduced pressure of 150° C. and 50 mmHg to obtain 132 g of novolak resin A.
FIG. 1 shows a gel permeation chromatography (GPC) chart of Resin A. The horizontal axis represents the elution time (minutes).

(Examples 2 to 4 and 7 to 9, Reference Examples 2 and 3, Comparative Examples 1 to 8)
Novolak resins B to N were obtained by performing the reaction in the same manner as in Example 1 except that the compounds and reaction conditions shown in Table 1 and Table 2 were used. Incidentally, in the compositions of Comparative Examples 4 to 6, the reaction did not proceed and the resin could not be obtained.
2 shows a GPC chart of resin 1 and FIG. 3 shows a GPC chart of resin J, respectively.

The physical properties of the novolak resins described in the composition tables of Examples 1 to 4 and 7 to 9, Reference Examples 2 and 3, and Comparative Examples 1 to 3 and 7 to 8 were measured by the following analysis methods.
(1) Gel Permeation Chromatography (GPC) For the column configuration, two Shokho (registered trademark) column product names "KF-804" of organic solvent-based SEC (GPC) columns manufactured by Showa Denko KK were used. As the detector, a differential refractometer “SHODEX” (registered trademark) refractometer, trade name “RI-71” was used. Tetrahydrofuran was used as a solvent, and the flow rate was 1 ml/min.
(2) Melt viscosity (mPa·S)
The measurement was carried out at 150° C. using an ICI viscometer manufactured by Research Equip.

Comparing FIGS. 1, 2 and 3, it can be confirmed that the resins A and I tend to have a low degree of dispersion (weight average molecular weight/number average molecular weight) even when the reaction molar ratio is high to some extent. That is, the novolak resin obtained by the present invention has a feature that a high molecular weight component is hard to be produced, and as shown in Tables 1 and 2, it can be confirmed that the resin has a low melt viscosity and a higher fluidity.
Usually, in the novolac resin, the higher the aldehyde/phenols reaction molar ratio or the higher the reaction temperature, the more easily the high molecular weight component is produced, and the fluidity of the resin tends to decrease. It can be confirmed that the resin obtained by the present invention has a low melt viscosity even in a resin having a high reaction molar ratio and has a good fluidity.

(Examples 10 to 13 , 16 to 18 , Reference Examples 4 and 5 , Comparative Examples 9 to 13)
To 10 parts by mass of the epoxy resin shown in Tables 3 and 4, novolak resins A to N in an amount of epoxy equivalent/hydroxyl group equivalent=1/1 were melt-mixed at 110° C. respectively, and 1 part by mass of triphenylphosphine (curing accelerator) and an amount of fused silica (inorganic filler) in an amount of 80% by mass in the composition were mixed for 5 minutes with a two-roll mill heated to 110° C., A thermosetting resin composition was prepared. The respective formulations are shown in Tables 3 and 4.

The resulting thermosetting resin composition was pressure-molded in a mold at 150° C. for 30 minutes at a pressure of 30 kg/cm ² . Then, it was post-cured at 180° C. for 5 hours to prepare a test piece having a length of 95 mm, a width of 10 mm and a thickness of 4 mm.
The glass transition temperature, the water absorption rate, and the bending elastic modulus under the conditions of 25° C. and 260° C. of the obtained test piece were evaluated by the following methods.
(3) Glass transition temperature The glass transition temperature was measured by the TMA method using a trade name “SSC/5200” manufactured by Seiko Instruments Inc. (SII). The temperature rising rate was 10° C./min, and the sample size was 4 mm wide×10 mm long×8 mm thick.
(4) Water absorption rate Using an unsaturated high-acceleration life tester “PC-422R8” (trade name) manufactured by Hirayama Seisakusho Co., Ltd., the rate of weight increase after 20 hours at 121° C. and 100% humidity Was measured.
(5) Flexural Modulus Tensilon universal tester (trade name "Tensilon UTM-5T" manufactured by Toyo Baldwin Co., Ltd. was used to measure according to JIS K-6911. The elastic modulus shown in Table 2 is The elastic modulus is 25° C. at room temperature and 260° C. when heated.

In the formulations of Tables 3 and 4, the following were used as the epoxy resin, triphenylphosphine, and fused silica.
Epoxy resin: Mitsubishi Chemical Co., Ltd. (triphenylmethane type epoxy resin), trade name "1032H60"
Triphenylphosphine: Wako Pure Chemical Industries, Ltd. Fused silica: Tatsumori Co., Ltd., trade name “MSR-2212”

From Tables 3 and 4, the cured product of the thermosetting resin composition obtained by using the resin of the present invention had a lower water absorption rate than that of Comparative Example, and a low elastic modulus at 260° C. was obtained. .. That is, it can be said that it exhibits lower water absorption and flexibility than the case of using the conventional materials such as phenols/formaldehyde novolac resin (Comparative Examples 9 and 10).
As described above, according to the present invention, by providing a novolak resin having excellent fluidity, it becomes possible to obtain a cured product having excellent moisture resistance and flexibility by using it.

(Examples 19 to 21, Comparative Example 14, Reference Example 1)
Novolak resins O and Q to T were obtained by performing the reaction in the same manner as in Example 1 except that the compounds shown in Table 5 and the reaction conditions were used. The results are shown in Table 5. The pKa of valeric acid used in Comparative Example 14 is 5.17.

(Examples 22 to 24)
In the same manner as in Example 10, a thermosetting resin having the composition shown in Table 6 was prepared using the obtained novolac resins O, Q, and S, and a test piece was prepared and evaluated. Table 6 shows the glass transition temperature, the water absorption rate, and the flexural elastic modulus values under the conditions of 25°C and 260°C of the obtained test piece.

The method for producing a novolac resin of the present invention improves the fluidity of the produced novolac resin, improves the flexibility of the cured product of the resin composition using the novolac resin, and can also impart moisture resistance. A novolac resin is provided. Further, the novolac resin obtained in the method for producing a novolac resin is a resin composition for an encapsulating material for electronic parts, a resin composition for a printed circuit board, a resin composition for an interlayer insulating material used for a printed circuit board and a copper foil with resin. , A conductive paste (containing a conductive filler), a paint, an adhesive, a composite material, and the like.

Claims (8)

Phenols selected from phenol or cresol and octyl aldehyde as a saturated aliphatic aldehyde, or octyl aldehyde and aromatic aldehyde are added in a total mole number of aldehyde of 0.4 to 0 with respect to 1 mole of phenols. The following general formula (1) is used at a molar ratio of 0.8 mol.
B-(OR) ₃ (1)
(In the formula, each of the three R's independently represents a hydrogen atom or an alkyl group having 1 to 10 carbon atoms.) and a pKa at 25° C. of 0.0 or more . Reacting in the presence of 0 or less acid , and using 0.05 to 5 parts by mass of the boron compound and 0.05 to 5 parts by mass of the acid with respect to 100 parts by mass of the phenols. A method for producing a novolac-type phenolic resin, which comprises: The method for producing a novolac type phenolic resin according to claim 1, wherein the aromatic aldehyde is represented by the general formula (2).

(In the formula, A represents a residue obtained by removing a+1 hydrogen atoms from a monocyclic or polycyclic aromatic hydrocarbon, and R1 independently represents an alkyl group having 1 to 6 carbon atoms, a hydroxy group, or a carbon atom number. Represents an alkoxy group of 1 to 6 or a halogen atom, and a is an integer of 0 to 3.) The method for producing a novolac phenolic resin according to claim 1 or 2 , wherein the aromatic aldehyde is one or more compounds selected from benzaldehyde and salicylaldehyde. The boron compound is boric acid, the production method of the phenolic novolak resin according to any one of claims 1-3. Produced by the method according to any one of claims 1-4 novolac type phenolic resin. A thermosetting resin composition containing the novolac-type phenol resin according to claim 5 and an epoxy resin. The thermosetting resin composition according to claim 6 , further comprising a filler. Cured product obtained by curing the thermosetting resin composition according to claim 6 or 7.