JPS59149918A - Production of cyanate group-containing phenolic resin - Google Patents

Abstract

PURPOSE:To improve the recovery operation and yield of trialkylamines, by reacting a trialkylammonium salt of phenol novolak with a cyanogen halide and at the same time using a specified process for recovering trialkylamines. CONSTITUTION:In a process for producing a cyanate group-containing phenolic resin by reacting a trialkylammonium salt of phenol novolak with an excess of a cyanogen halide in an organic solvent; use is made of a recovery process comprising a step of dissolving and separating the hydrohalide salt of the trialkylamine by-product into an aqueous solution by mixing water and the reaction solution obtained by reacting the trialkylammonium salt of phenol novolak with an excess of cyanogen halide by using a water-immiscible solvent as the organic solvent, and a step of separating the trialkylamines liberated by adding an alkali to the above aqueous solution by distillation, liquid-liquid separation, or extraction with a water-immiscible solvent.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for producing a cyanato group-containing phenolic resin, which is characterized by a trialkylamine recovery process that enables industrial recovery and reuse of the trialkylamine.

Conventionally, the manufacturing method of cyanato group-containing phenolic resin is as follows:
A method in which a novolac having an average molecular weight of about 600 to 1500 that is soluble in an organic solvent is reacted with cyanogen halide at a temperature of -30 to 65°C in the presence of a base in a solvent (Japanese Patent Publication No. 45
-'M712), a method in which a phenol novolak having a number average molecular weight of 300 or more and less than 600 is reacted with cyanogen halide in the presence of a base (Japanese Patent Publication No. 56-42076), and the like are known.

Although novolac is not exemplified as a raw material compound to be used, there is also a method in which excess cyanogen halide is reacted with di- or polytria/rekyl ammonium felt in the presence of a trialkylamine and an organic solvent (
JP-A No. 51-408037) is known.

The present inventors conducted intensive studies on an industrial method for producing a cyanato group-containing phenol resin suitable for obtaining a cured resin product with excellent properties such as thermal properties, and found that the phenol novolac is a trialkylammonium salt. As a result, it is well soluble in a solvent such as dichloromethane, and a solution of the trialkylammonium salt of this phenol novolac can be dissolved even in the absence of free trialkylamine in an organic solvent solution of cyanogen fluoride. It was discovered that a cyanato group-containing phenol resin with excellent curing properties could be obtained by effectively reacting with the phenol resin, and a patent application was filed as % Application No. 132528/1983.

After that, as a result of intensive research on a more industrially superior method, we discovered that the hydrohalide salt of the by-product trialkylamine in the reaction solution was dissolved and separated in an aqueous solution, and an alkali was added to it, making it easy to process for free trialkyl. They discovered that this is the case and completed the present invention.

That is, the present invention provides a method for producing a cyanate ester group-containing phenol resin by reacting a trialkylammonium salt of a phenol novolak with an excess of /10 cyanide in an organic solvent, in which a water-immiscible solvent - Mix water with the reaction solution obtained by reacting the triplekylammonium salt of phenol novolac with excess /N P genation using It is characterized by the recovery process of trialkylamine, which consists of the process of dissolving and separating the alkali into the aqueous solution, and the process of distilling, separating, or extracting the liberated trialkylamine with a water-immiscible solvent.Containing sulcyanato groups This is a method for producing phenolic resin.

The configuration of the present invention will be explained below.

The novolak of the present invention has a number average molecular weight of 300 to 1500.
More preferably, it is a novolak obtained from formaldehyde and a phenol having a molecular weight of 300 to 600, such as phenol, cresol, or xylenol, and is represented by the following formula.

(R1-R4 in the formula represent a hydrogen atom or a methyl group,
They may be the same and may be different. n + t is a positive number from 1 to 10. ) Trialkylamine is a compound represented by the following formula % (Rs r R6, R7 in the formula represents a straight chain or branched button alkyl group having 1 to 4 carbon atoms), and trimethylamine , triethylamine, dimethylethylamine A, methyldiethylamine, tripropylamine, triisopropylamine, tributylamine, and the like.

The above-mentioned novolac and triflukyl 7mine are mixed and reacted in the presence of an organic solvent to obtain a trialkylammonium salt solution of the novolac. The ratio of novolak to trialthousylamine is usually 1 molecule of triflukylamine per 1 m of phenolic hydroxyl group to be cyanated in the novolak. If the trialkylamine is insufficient, unreacted phenolic hydroxyl groups will increase, and if it is in excess, an excessive amount of cyanogen halide will also be required, which is not preferable.

As the cyanogen halide, plucian and bromcyan can be used, but chlorocyan is particularly preferred. The amount of cyanogen halide to be used is one or more molecules, preferably 1 to 2 molecules, per hydroxyl group to be cyanated of the phenol novolac triflukylammonium salt of 13 Ft $1 per trialkylammonium salt.

The water-immiscible organic solvent used in the present invention means that it undergoes phase separation, and hydrocarbons, chlorinated hydrocarbons, nitrohydrocarbons, ethers, etc. can be used. Examples include: Petroleum ether, benzene, toluene, xylene, dichloromethane, chloroform, carbon tetrachloride, dichloromethane, perchloroethane, chlorobenzene, dichlorobenzene, nitromethane, nitrobenzene, nitrotoluene, diethyl ether, diimpropyl ether, methyl-ter-butyl ether It is.

It should be noted that water mixed into the reaction system from the solvent and raw materials used tends to increase the resultant force 1 of unreacted phenolic -〇H groups, so it is preferable that the amount of water in the system is small. 0.2 of the triple kylammonium salt of
The following should be used.

The reaction of the present invention is carried out using the phenol solution described above at 5°C.
This is done by introducing this.

The reaction solution obtained in this reaction step has +64. A2. Ya7. A1v (Op, 2A7'i, yo□.

It becomes a solution in which salt crystals are dispersed.

By mixing water with this reaction solution and washing with water, dissolving the by-product salt in water and separating the layers, the amount of cyanato group-containing phenol resin solution and by-product trialkylamine used is usually 0.2% of the reaction solution. -6 times by weight, and the water mixing temperature is usually 0 to 30°C, preferably 10 to 60°C.

Next, a stoichiometric amount or more of an alkali or alkaline earth metal hydroxide such as sodium hydroxide, potassium hydroxide, calcium hydroxide, etc. is added to one aqueous salt solution of trialkylamine, and triple kill is released. amine,
It is separated and recovered by distillation, separation, or extraction with a water-immiscible solvent. Here, the amount of alkali used in the salt aqueous solution of triflukylamine is
Since some of the I-cyanogenide dissolved in +J is required, more than the equivalent of tolyalkylamine is required. In the case of low-boiling amines that are soluble in water, high-boiling amines with low solubility in water are distilled.

In the case of water, it is separated and recovered from the aqueous solution by liquid separation or extraction with a water-immiscible organic solvent. The solvent used in the extraction method is preferably the same as that used in the reaction step.

The trialkylamine recovered as described above and further the water-immiscible solvent may be removed from components harmful to the reaction, if necessary.
For example, water etc. are removed and recycled as reaction solvents and raw materials.

The desired resin can be obtained by removing the solvent under reduced pressure from the reaction product solution from which by-product salts obtained in the separation process have been removed, or by dropping the reaction product solution dropwise into the poor solvent of this grafted blade. can get.

According to the method of the present invention, in a method for producing a cyanate ester group-containing phenol resin by reacting a triplekylammonium salt of a phenol novolac with an excess of cyanide halide in an organic solvent, trialkylamine can be industrially produced from the reaction solution. Since the cyanate ester group-containing phenolic resin can be recovered economically, it is possible to industrially produce cyanate ester group-containing phenolic resin with very excellent properties during curing at low cost.

EXAMPLES Below, the present invention will be explained in more detail with reference to Examples.

Example 1 (A) & Phenol novolac 4E with average molecular weight 328
N''?Dissolved in a mixed solution of dimethylethylamine 34P, o-dichlorobenzene 96g, stirred at 0°C, and dropped into a solution of prussian 51Lt, O-dichlorobenzene 122y, followed by an aging reaction for 30 minutes. Ta.

[F]) 110 crimson water was added to the above reaction solution in three portions, and by-product dimethylethylamine hydrochloride in the reaction solution was fermented and decomposed into the aqueous phase.

A cyanate ester group-containing phenol resin was obtained by vacuum concentration from the reaction solution from which dimethylethylamine hydrochloride was separated.
Obtained 9.7p. This resin was in liquid form and had a number average molecular weight of 480 according to GPC measurement.

D To the aqueous phase in which the 2-methylethylamine hydrochloride obtained in (B) was dissolved, NaOH (purity 95%) 21z was added with stirring, and the dimethylethylamine that had been soaked in water was added to the aqueous phase. T'+)E A fraction collected by distillation and having a boiling point of 36°5 to 37.5°C s
2. Obtained qy. The recovery rate of dimethylethylamine is 96
．． It was 8%.

Example 2 The same phenol novolak 481 as in Example 1 was dissolved in a mixed solution of triethylamine 47.4P and dichloromethane 96P, and stirred at 0°C.
After dropping it into a solution of dichloromethane 1221, the mixture was allowed to undergo an aging reaction for 60 minutes.〇 It was dissolved and separated into the aqueous phase.

A cyanate ester group-containing phenol resin is obtained by vacuum concentration from the reaction solution from which triethylamine hydrochloride has been separated 59.
I got 87. This resin was in liquid form and had a number average molecular weight of 480 according to GPC measurement.

(C) 2 ip of NaOH (purity 9596) was added to the aqueous phase in which the triethylamine hydrochloride obtained in step 0 was dissolved, and the liberated triethylamine was extracted with 94 g of dichloromethane. The weight of the extract is 147y, and the composition is triethylamine 31.8wt%, dichloromethane 66.7wt%.
wt%, H2C'I.

5 wt%, and the recovery rate of triethylamine was 98.6
%Met.

Example 3 (5) The same phenol novolac as in Example 1 was substituted with 48% tri-n-butylamine 86. The solution was dissolved in a mixed solution of F3f- and dichloromethane 96g, and added dropwise to a solution of chlorocyan 31p and dichloromethane 122F with stirring at 0°C, followed by an aging reaction for 30 minutes.

150 ml of water was added to the above reaction solution in three portions, and the by-product tri-n-butylamine salinization salt in the reaction solution was dissolved and separated into the aqueous phase.

)! The reaction solution from which J = n-7' thylamine hydrochloride was separated was concentrated under reduced pressure to obtain 59.8@ of a phenol resin containing a lysyanate group. This resin is liquid and G P
According to CmlJ constant, the number average molecular weight was 480.

C) The g obtained in ()3)! j -n-bu, thylamine hydrochloride dissolved in the aqueous phase was stirred with NaOH (95% purity).
211 was added, and the tri-n-butylamine separated into the upper layer was recovered by liquid separation. Collected)! J-n-butylamine was 84.37, and the recovery rate was 96.1%.

Example 4 (g) Cresol novolak with an average molecular weight of 550 and 48 triethylamine 41. ．． 5f.

Dissolved in a mixed solution of 96f dichloromethane and stirred at 0°C. Chlorcyan 29.49, dichloromethane 122
After dropping it into the solution of z, an aging reaction was carried out for 30 minutes.

■ Add 1jOxt of water to the above reaction solution in 6 parts,
The by-product triethylamine hydrochloride in the reaction solution was dissolved and separated into the aqueous phase.

Solid resin containing cyanate ester group by vacuum compression from the reaction solution from which triethylamine hydrochloride has been separated 57.854
I got it.

C) To the aqueous phase in which the triethylamine hydrochloride obtained in (i3) was dissolved, 21 g of NaOH (purity 95%) was added with stirring, and the released triethylamine was dissolved in dichloromethane.
Extracted at 124°C. The weight of the extract was 171.6 kg, and the composition was triethylamine 24,0 wt9ot.
Dichloromethane 74.6wt%, H2C1.4wt%
The recovery rate of triethylamine was 99.7%.

Patent applicant Mitsubishi Gas Chemical Co., Ltd. Company representative Kazuyoshi Nagano

Claims (1)

[Claims] In a method for producing a cyanate ester group-containing phenolic resin by reacting a trialkylammonium salt of Fe/-crucvolac with an excess of cyanogenide in an organic solvent, a water-immiscible solvent is used as the organic solvent. A reaction solution obtained by reacting a trialkylammonium salt of phenol novolak with excess cyanogenide,
A process of mixing water with j and dissolving and separating by-product trialkylamine I-hydrogenide into an aqueous solution, and adding an alkali to the aqueous solution to remove the liberated trialkylamine by distillation, liquid separation, or water immiscibility. A method for producing a cyanato group-containing phenolic resin characterized by a trialkylamine recovery process comprising a step of extraction with a solvent.