KR20110101189A - Method for producing novolac resin, and novolac resin - Google Patents

Abstract

A method for efficiently producing a low molecular weight novolak resin by reacting phenols and aldehydes under mild conditions, wherein formula (I) B- (OR) ₃ (I) (wherein R is a hydrogen atom, And a phenol and an aldehyde in the presence of a boron compound represented by an alkyl group) and a catalyst containing an acid having a pKa of 5.0 or less.

Description

Manufacturing method of novolak resin and novolak resin {METHOD FOR PRODUCING NOVOLAC RESIN, AND NOVOLAC RESIN}

This invention relates to the manufacturing method for obtaining a low molecular weight novolak resin in high yield, and the novolak resin obtained by the said manufacturing method.

Phenolic resins are heat resistant and are used in various fields.

For example, when used as a curing agent for epoxy resins, the resin composition for printed circuit boards, resin compositions for interlayer insulating materials used in printed circuit boards and resin-coated copper foils because of excellent heat resistance, adhesion, electrical insulation, etc., resins for sealing materials for electronic parts It is used for compositions, resist inks, conductive pastes, paints, adhesives, composite materials and the like.

Recent technological innovations are required to further improve the heat resistance, moisture resistance, flame resistance, and the like of the epoxy resin composition.

One solution is to increase the amount of filler used.

By increasing the amount of filler, it is possible to reduce the linear expansion coefficient of the molded article, to reduce the moisture absorption rate, and to improve the flame retardancy. On the other hand, the increase of the filling amount causes the problem that the fluidity of the compound is lowered and the moldability is deteriorated. Melt viscosity is required.

Novolak resins are prepared by addition condensation of phenols and aldehydes in the presence of an acidic catalyst.

Usually, the molar ratio of aldehydes to phenols is used in the range of 0.3-0.9 mol, and the molecular weight of resin obtained is controlled by adjusting molar ratio.

In order to lower the melt viscosity of the resin, it is necessary to reduce the high molecular weight component as much as possible, but in order to obtain a novolak resin having a low molecular weight, the molar ratio must be reduced, in which case a large amount of unreacted phenol monomer remains.

The unreacted phenol monomers in the resin can be reduced by distillation under reduced pressure, but the lower the molar ratio, the larger the phenol monomers are removed by distillation.

On the other hand, when phenolic monomer remain | survives in resin, since the fall of the dimensional stability of a molded object, generation | occurrence | production of a void, etc. are caused, it is preferable that the phenol monomer in resin is as few as possible.

From such a background, the high yield of novolak resin was examined (refer patent document 1, 2).

In patent document 1, the method of disproportionate-reacting phenols and paraformaldehyde in presence of a phosphate catalyst is shown.

According to this method, the reaction rate of phenols is improved, but since the catalyst is limited to phosphoric acid, the reaction is less reactive than paraformaldehyde, for example, an aliphatic aldehyde such as acetaldehyde or butylaldehyde, and an aromatic aldehyde such as benzaldehyde or salicylicaldehyde. In this case, sufficient reactivity is not obtained.

In patent document 2, the method of reacting phenols and aldehydes in presence of an organic phosphonic acid catalyst is shown.

The monomer reaction rate is improved by forming the water phase in which a catalyst exists, and the organic phase in which resin is easy to melt | dissolve.

However, even in this method, since the catalyst is limited to organic phosphonic acid, sufficient reactivity is not obtained when reacting with an aldehyde having a lower reactivity than the above-mentioned formaldehyde.

Moreover, since the temperature of 110 degreeC or more is required for catalyst efficiency improvement, generation | occurrence | production of a high molecular weight is inevitable and it is unpreferable for obtaining low molecular weight novolak resin.

When reacting phenols with aliphatic aldehydes such as acetaldehyde or butyl aldehyde, benzaldehyde or salicylic aldehyde and phenols, a stronger acid than phosphoric acid or organic phosphonic acid such as hydrogen halide or sulfonic acid compound is used in large quantities, and The reaction temperature is necessary.

Under such conditions, it is difficult to obtain a high molecular weight novolak resin because a high molecular weight component is easily produced.

In order to obtain a low molecular weight novolak resin in high yield by using aldehydes having lower reactivity than formaldehyde or paraformaldehyde, there has been no effective production means until now.

Japanese Patent Laid-Open No. 2004-339257 Japanese Patent Publication No. 2002-194041

The present invention has been made on the basis of the above circumstances, and an efficient method for producing a low molecular weight novolak resin in which phenols and aldehydes, especially aliphatic aldehydes having 2 or more carbon atoms and aromatic aldehydes are reacted under mild conditions and obtained by the above production method It is an object to provide a novolak resin.

The present invention is based on the finding that the above problems can be achieved by reacting phenols and aldehydes in the presence of a boron compound and a catalyst containing an acid having a pKa of 5.0 or less.

That is, this invention makes the following a summary.

Formula (I)

B- (OR) ₃ (I)

(Wherein R represents a hydrogen atom and an alkyl group having 1 to 10 carbon atoms)

A method for producing a novolak resin, characterized in that phenols and aldehydes are reacted in the presence of a boron compound represented by the formula and a catalyst containing an acid having a pKa of 5.0 or less,

2. The method according to claim 1, wherein the acid has a pKa in the range of 0.0 to 4.0;

3. The method for producing a novolak resin according to claim 1, wherein the boron compound represented by formula (I) is boric acid,

4. The number average molecular weight of the novolak resin obtained by the manufacturing method of said 1 whose phenols are phenol or cresol, aldehydes are benzaldehyde, and the boron compound represented by Formula (I) is boric acid is 300-600, and disperse | distributes Novolak resin whose degree (weight average molecular weight / number average molecular weight) is 1.3 or less and whose melt viscosity in 150 degreeC is 300 mPa * s or less

(Effects of the Invention)

According to the present invention, by reacting phenols and aldehydes in the presence of a catalyst containing a boron compound and an acid having a pKa of 5.0 or less, an efficient method for producing a low molecular weight novolak resin and a novolak resin obtained by the production method can be provided. have.

1 is a GPC chart of a novolak resin in Example 1. FIG.
2 is a GPC chart of a novolak resin in Comparative Example 4. FIG.

EMBODIMENT OF THE INVENTION Hereinafter, this invention is demonstrated in detail.

In the manufacturing method of the novolak resin of this invention, in addition to the acid whose pKa is 5.0 or less, Formula (I)

B- (OR) ₃ (I)

(Wherein R represents a hydrogen atom and an alkyl group having 1 to 10 carbon atoms)

The boron compound represented by is used as an essential component.

The alkyl group having 1 to 10 carbon atoms as R may be linear or branched, and may be methyl, ethyl, propyl, isopropyl, butyl, isobutyl, sec-butyl, tert-butyl, pentyl or isopen. And a methyl group, sec-pentyl group, tert-pentyl group, neopentyl group, hexyl group, isohexyl group, heptyl group, octyl group and decyl group.

As a specific example of the boron compound represented by Formula (I), boric acid, trimethyl borate, triethyl borate, triisopropyl borate, tributyl borate, etc. are mentioned, It can be used individually or in mixture of 2 or more types.

Among these, boric acid is preferable practically.

The amount of the boron compound used is preferably 0.3 to 20 parts by mass, and preferably 1.0 to 10 parts by mass with respect to 100 parts by mass of the phenols.

If the amount of the boron compound used is less than 0.3 parts by mass, the reaction rate between phenols and aldehydes is lowered, which is not preferable. When the amount of the boron compound is more than 10 parts by mass, the effect of improving the reaction rate hardly changes.

As an acid whose pKa which is an essential component of the catalyst in this invention is 5.0 or less, what is necessary is just to be used for manufacture of general novolak resin, For example, hydrochloric acid, nitric acid, sulfuric acid, phosphoric acid, paratoluenesulfonic acid, oxalic acid, etc. are mentioned, It can be used individually or in mixture of 2 or more types.

If the pKa is an acid of more than 5.0, the effect as a catalyst is poor, which is not practical.

In consideration of corrosion to the reaction equipment and the yield of novolak resin, an acid having a pKa of 0.0 to 4.0 is preferable, and examples thereof include oxalic acid, phosphoric acid, salicylic acid and tartaric acid.

The amount of the acid having a pKa of 5.0 or less is preferably used in an amount of 0.1 to 20 parts by weight, preferably 0.1 to 10 parts by weight, and more preferably 0.2 to 5 parts by weight with respect to 100 parts by weight of phenols.

The method for producing a novolak resin of the present invention is to react phenols and aldehydes in the presence of a boron compound and an acid having a pKa of 5.0 or less.

The phenols used in the method of the present invention may be those used for the production of general phenol resins, and for example, phenol, various cresols, various ethyl phenols, various xylenols, various butyl phenols, various octyl phenols, various nonyl phenols and various phenyls. Phenol, various cyclohexyl phenols, various trimethyl phenols, bisphenol A, catechol, resorcinol, hydroquinone, various naphthols, pyrogallol and the like can be used alone or in combination of two or more thereof.

Among these, phenol and various cresols are preferable in practical use.

On the other hand, as aldehydes made to react with phenols, it can be used if it is aldehydes which can be used for manufacture of a phenol resin.

For example, formaldehyde, acetaldehyde, benzaldehyde, paraformaldehyde, various propylaldehydes, various butylaldehydes, various valericaldehydes, various hexylaldehydes, glyoxal, crotonaldehyde, glutaraldehyde, various hydroxybenzaldehyde, various hydroxybenzaldehyde Roxy benzaldehyde, various hydroxymethyl benzaldehyde, etc. can be used individually or in mixture of 2 or more types.

The amount of the aldehydes used is preferably 0.3 to 1.0 mol, preferably 0.4 to 0.9 mol relative to 1 mol of the total amount of phenols.

When the amount of the aldehydes used is less than 0.3 mol, the remaining phenol monomers increase, which is not efficient.

On the other hand, when aldehydes exceed 1.0 mol, since the molecular weight of the novolak resin obtained becomes high, it is unpreferable.

In the present invention, the novolak resin obtained by using phenol or cresol as phenol, benzaldehyde as aldehyde, and boric acid as boron compound represented by formula (I) has a number average molecular weight of 300 to 600, and a degree of dispersion (weight average molecular weight / Number average molecular weight) is 1.3 or less, or melt viscosity in 150 degreeC is 300 mPa * s or less.

If the number average molecular weight of the novolak resin obtained is in the said range, the melt viscosity of a novolak resin can be made low and it exhibits a sufficient effect as a hardening | curing agent of an epoxy resin.

Dispersion of 1.3 or less means that there are few high molecular weight polynuclear bodies in novolak resin.

Moreover, dispersion degree becomes like this. Preferably it is 1.2 or less.

When the melt viscosity is 300 mPa · s or less, when used as a curing agent for an epoxy resin, the flowability of the compound is improved, and thus a compound having excellent moldability is obtained.

Moreover, melt viscosity in 150 degreeC becomes like this. Preferably it is 250 mPa * s or less.

In order to lower the melt viscosity of a novolak resin, it is necessary to make content of a polynuclear body as small as possible.

There is no restriction | limiting in particular in the method of making phenols and aldehydes react, For example, a method which makes it react by putting together phenols and aldehydes, a boron compound represented by Formula (I), and an acid of pKa 5.0 or less, or phenols and a formula ( The boron compound represented by I) and the acid of pKa 5.0 or less are added, and the method of adding aldehydes at predetermined reaction temperature is mentioned.

In this case, the reaction temperature may be performed in a range of 30 to 120 ° C.

If it is less than 30 ° C, the progress of the reaction is slow, and unreacted phenols remain, which is not preferable, and at a temperature exceeding 120 ° C, it is not preferable because the production of high molecular weight components is promoted.

There is no restriction | limiting in particular in reaction time, It is good to adjust with the quantity of aldehydes, a catalyst, and reaction temperature.

It is also possible to use an organic solvent when reacting.

Examples of such organic solvents 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 mono Glycol ethers such as methyl ether, butylene glycol monoethyl ether, butylene glycol monopropyl ether, ketones such as methyl ethyl ketone and methyl isobutyl ketone, propyl acetate, butyl acetate, ethyl lactate, ethylene glycol monomethyl ether acetate, Ester, such as propylene glycol monomethyl ether acetate, ether, such as 1, 4- dioxane, etc. can be used individually or in combination of 2 or more types.

The said organic solvent can be used so that it may become 0-1,000 mass parts with respect to 100 mass parts of phenols, Preferably it is about 10-100 mass parts.

After the reaction, the condensed water may be removed by distillation or washed with water as necessary to remove the remaining catalyst.

Distillation under reduced pressure or steam distillation may further remove unreacted phenols and unreacted aldehydes.

Example

Although the Example of novolak resin by the manufacturing method of this invention is shown below and this invention is demonstrated further more concretely, this invention is not limited to these.

Example 1

100 g of orthocresol, 49 g of benzaldehyde, 1 g of boric acid, and 1 g of oxalic acid (pKa = 1.04) were added to a flask equipped with a cooling tube and a stirrer, and the mixture was reacted at 100 ° C for 8 hours.

Subsequently, washing was performed twice with 100 g of pure water to remove the catalyst.

Subsequently, the outflow fraction was removed under reduced pressure of 180 degreeC and 50 mmHg, and 94 g of novolak resin A was obtained.

The gel permeation chromatography (GPC) chart of Resin A is shown in FIG. In addition, the horizontal axis shows an elution time (minute).

It can be seen from FIG. 1 that Resin A has a low molecular weight binary nucleus as the main product.

Example 2

98g of novolak resin B was obtained like Example 1 except having used methacresol as phenols.

Example 3

A novolak resin C 92g was obtained in the same manner as in Example 1 except that 56g of salicyaldehyde was used as the aldehyde.

Example 4

A novolak resin D 94g was obtained in the same manner as in Example 1 except that 56 g of metahydroxybenzaldehyde was used as the aldehyde.

Example 5

The reaction was carried out in the same manner as in Example 1, except that the reaction was carried out at 50 ° C. for 10 hours using 1.7 g of trimethyl borate instead of boric acid, to thereby obtain 97 g of novolak resin E.

Example 6

The reaction was carried out in the same manner as in Example 1, except that 1 g of phosphoric acid (pKa = 2.12) was used instead of oxalic acid to obtain 90 g of novolak resin F.

Comparative Example 1

100 g of orthocresol, 49 g of benzaldehyde, 12 g of sodium borate, and 1 g of oxalic acid were added to a flask equipped with a cooling tube and a stirrer, and the mixture was allowed to react at 100 ° C for 8 hours, but no resin was obtained because the reaction did not proceed.

Comparative Example 2

100 g of orthocresol, 49 g of benzaldehyde, and 1 g of oxalic acid were added to a flask equipped with a cooling tube and a stirrer, and the mixture was allowed to react at 100 ° C. for 8 hours.

Comparative Example 3

100 g of orthocresol, 49 g of benzaldehyde, 1 g of boric acid, and 1 g of valeric acid (pKa = 5.17) were added to a flask equipped with a cooling tube and a stirrer, and the mixture was allowed to react at 100 ° C for 8 hours, but no resin was obtained because the reaction did not proceed.

Comparative Example 4

100 g of orthocresol, 49 g of benzaldehyde, and 10 g of paratoluene sulfonic acid were placed in a flask equipped with a cooling tube and a stirrer, and the mixture was reacted at 100 ° C for 8 hours.

Subsequently, after neutralizing with aqueous sodium hydroxide solution, washing was performed 5 times with 100 g of pure water to remove salts.

Subsequently, the distillate was removed under reduced pressure of 180 degreeC and 50 mmHg, and 77 g of novolak resin G was obtained.

2, the gel permeation chromatography (GPC) chart of Resin E is shown. In addition, the horizontal axis shows an elution time (minute).

It can be seen from FIG. 2 that Resin E has a considerable amount of polynuclear body formed in addition to the nucleolus.

Comparative Example 5

Except having used methacresol as phenols, it carried out similarly to the comparative example 4, and obtained 82 g of novolak resin H.

The value measured by the following analysis method about the novolak resin obtained in Examples 1-6 and the novolak resin obtained in Comparative Examples 4 and 5 is shown in Table 1.

The analysis method of resin is as follows.

(1) Number average molecular weight, weight average molecular weight, dispersion degree

It measured by gel permeation chromatography (GPC).

The column structure measured two flow rates of 1 ml / min using tetrahydrofuran as a solvent using two KF-804 by Showa Denko Corporation.

Molecular weight calculated | required polystyrene conversion and content rate as a percentage of the whole peak area.

Dispersion was computed by weight average molecular weight / number average molecular weight.

(2) Softening point (℃)

It measured at the temperature increase rate of 2.5 degree-C / min using the Erex Kagaku vapor-phase softening point measuring apparatus EX-719PD.

(3) Melt viscosity (mPas)

It measured at 150 degreeC using the ICI viscometer by a research company.

Example 7

Into a flask equipped with a cooling tube and a stirrer, 100 g of orthocresol, 49 g of benzaldehyde, 2 g of salicyaldehyde, 1 g of boric acid, and 1 g of oxalic acid were added and reacted at 100 ° C. for 8 hours.

Subsequently, washing was performed twice with 100 g of pure water to remove boric acid and oxalic acid.

Subsequently, the distillate was removed under reduced pressure of 180 ° C. and 50 mmHg to obtain 92 g of novolak resin I.

Example 8

Reaction was performed like Example 7 except having used methacresol as phenols, and novolak resin J 97g was obtained.

Example 9

The reaction was carried out in the same manner as in Example 7, except that 50 g of orthocresol and 50 g of paracresol were used as phenols to obtain novolak resin K 94 g.

Example 10

The reaction was carried out in the same manner as in Example 7, except that 2 g of 2,4-dihydroxybenzaldehyde was used instead of salicylic acid to obtain 93 g of novolak resin L.

Comparative Example 6

Into a flask equipped with a cooling tube and a stirrer, 100 g of orthocresol, 49 g of benzaldehyde, 2 g of salicyaldehyde, and 1 g of oxalic acid were added and reacted at 100 ° C. for 8 hours.

Comparative Example 7

100 g of orthocresol, 49 g of benzaldehyde, 2 g of salicylaldehyde, and 1 g of boric acid were added to a flask equipped with a cooling tube and a stirrer.

The value measured by the said analytical method about the novolak resin obtained in Examples 7-10 is shown in Table 2.

Since the novolak resin of this invention has a low molecular weight, fluidity is high, and the thermosetting resin composition used as a hardening | curing agent of an epoxy resin improves the fluidity | liquidity at the time of shaping | molding remarkably.

When the novolak resin of this invention is used for a semiconductor sealing material, by increasing the amount of filler, the reduction of the linear expansion coefficient of a molded article, the reduction of a moisture absorption rate, and the flame retardance can be improved.

Moreover, the hardened | cured material has favorable heat resistance, moisture resistance, mechanical property, electrical insulation, adhesiveness with a metal, etc., and is very effective for the electronic material use which requires high reliability.

Specifically, resin compositions for sealing materials for electronic components, resin compositions for printed boards, resin compositions for interlayer insulating materials used in printed boards and resin coated copper foils, resist inks, conductive pastes (including conductive fillers), paints, adhesives, and composite materials. It can be used.

Claims (4)

Formula (I)
B- (OR) ₃ (I)
(Wherein R represents a hydrogen atom and an alkyl group having 1 to 10 carbon atoms)
A method for producing a novolak resin, wherein the phenols and aldehydes are reacted in the presence of a boron compound represented by the above and a catalyst containing an acid having a pKa of 5.0 or less. The method of claim 1,
PKa of the said acid is the range of 0.0-4.0, The manufacturing method of the novolak resin characterized by the above-mentioned. The method of claim 1,
The boron compound represented by said formula (I) is boric acid, The manufacturing method of the novolak resin characterized by the above-mentioned. Phenols are phenol or cresol, aldehydes are benzaldehyde, and the boron compound represented by Formula (I) is boric acid, The number average molecular weight of the novolak resin obtained by the manufacturing method of the novolak resin of Claim 1 is 300-600. And dispersion degree (weight average molecular weight / number average molecular weight) is 1.3 or less, and melt viscosity in 150 degreeC is 300 mPa * s or less, The novolak resin characterized by the above-mentioned.

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