JPH11147926A - Production of phenol/aldehyde resin - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a process whereby the objective product can be very easily removed in the form of a solid, and a refined phenol/aldehyde resin can be produced from a crude phenol/aldehyde resin. SOLUTION: There is provided a process for producing a refined phenol/ aldehyde resin from a crude phenol/aldehyde resin containing an organic solvent and a phenol/aldehyde resin, which process comprises transferring the phenol/ aldehyde resin to an aqueous layer by the action of an alkali on the crude phenol/aldehyde resin in the presence of water, separating the aqueous layer from the organic solvent layer and precipitating the phenol/aldehyde resin from the aqueous layer by the addition of the aqueous layer to a solution of an acid.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for producing a phenol-aldehyde resin, and more particularly to a method for separating a purified phenol-aldehyde resin from a crude phenol-aldehyde resin containing an organic solvent and a phenol-aldehyde resin. The present invention relates to a method for producing a resin.

[0002]

2. Description of the Related Art Phenol-aldehyde resins are widely used as raw materials for molding materials, adhesives, paints, electronic parts and the like, and as raw materials for resins such as epoxy resins and ion exchange resins. Phenol
Synthesis of the aldehyde resin is performed by reacting a phenol with an aldehyde in the presence of an acid catalyst or an alkali catalyst. For the homogeneous progress of the reaction, water or an organic solvent is used as a solvent.However, as a method for separating the purified phenol-aldehyde resin from the solvent, the solvent is distilled off, cooled, and the precipitated resin is collected by filtration. And the like.

When a phenol-aldehyde resin is used as a raw material for a functional material such as an epoxy resin for electronic parts, in order to develop heat resistance and other required physical properties,
Polyphenols and polycyclic phenols,
A phenol-aldehyde resin having a high melting point and low solubility is used, for example, an aromatic aldehyde is used as the aldehyde. An organic solvent having excellent solubility is required for the synthesis of such a phenol-aldehyde resin. However, in order to perform industrial production, in the step of separating the resin from the solvent, there are difficulties with the above-mentioned known method. Was. That is, when the solvent is distilled off, the solvent has a high boiling point and the resin has a high melting point, so that the distillation is incomplete, the yield is poor when the resin is precipitated, and the mixture is mixed when the solvent is added to the poor solvent. It is necessary to regenerate the used solvent.

[0004]

SUMMARY OF THE INVENTION An object of the present invention is to solve the above-mentioned disadvantages of the known method, to obtain a target substance extremely easily as a solid, and to obtain an industrially excellent crude phenol-aldehyde. Purified phenol from resin
It is to provide a method for producing an aldehyde resin.

[0005]

Means for Solving the Problems The present inventors have conducted intensive studies in order to develop a more excellent method for producing a purified phenol-aldehyde resin. As a result, the crude phenol-aldehyde resin is treated by a specific method. As a result, it has been found that the above object can be achieved, and the present invention has been completed.
That is, in the present invention, when producing a purified phenol-aldehyde resin from a crude phenol-aldehyde resin containing an organic solvent and a phenol-aldehyde resin, an alkali is allowed to act on the crude phenol-aldehyde resin in the presence of water to form a water layer. Transferring the phenol-aldehyde resin, separating the aqueous layer and the organic solvent layer, and then adding the aqueous layer to an acid solution to precipitate the phenol-aldehyde resin, the method for producing a purified phenol-aldehyde resin. Things.

[0006]

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, the present invention will be described in detail. The crude phenol-aldehyde resin used in the present invention only needs to contain at least an organic solvent and a phenol-aldehyde resin, and may contain water, acids, alkalis,
It may contain salts and the like.

A typical example of the crude phenol-aldehyde resin is, for example, a reaction mass obtained by subjecting a phenol and an aldehyde to a condensation reaction in the presence of a catalyst in an organic solvent, or a mixture obtained by mixing the phenol-aldehyde resin with an organic solvent. A mixed solution is exemplified. Representative examples of the phenol-aldehyde resin include those obtained by reacting the following phenols and aldehydes in combination. Phenols and aldehydes may be used alone or in combination of two or more. As phenols, phenol, cresol, xylenol, ethylphenol, butylphenol, t-butyl-methylphenol, phenylphenol, chlorophenol, bromophenol, resorcin, catechol, hydroquinone and the like are used. Aldehydes include formaldehyde, trioxane, paraformaldehyde, acetaldehyde, acrolein, benzaldehyde, hydroxybenzaldehyde, vanillin, isovanillin,
Glioxizal or the like is used. In the present invention, suitable phenol-aldehyde resins include, for example, those represented by the general formula (1)

[0008]

Embedded image (Wherein, R is independently a hydrogen atom, a halogen atom, a hydrocarbon group having 1 to 6 carbon atoms or an alkoxy group having 1 to 6 carbon atoms, and R ′ is a hydrogen atom or a hydrocarbon group having 1 to 6 carbon atoms. , A, b, and c each independently represent a number of 0 to 2, and m and n each independently represent a number of 0 to 5 on average). Here, as the halogen atom, fluorine, chlorine,
Bromine and iodine. Examples of the hydrocarbon group having 1 to 6 carbon atoms include a linear or branched alkyl group of methyl, ethyl, propyl, butyl, pentyl, and hexyl, a cyclohexyl group, and a phenyl group. Examples of the alkoxy group having 1 to 6 carbon atoms include linear or branched alkoxy groups such as methoxy, ethoxy, propoxy, butoxy, pentoxy, and hexoxy.

Although the present invention uses a crude phenol-aldehyde resin containing at least an organic solvent and a phenol-aldehyde resin, a hydrophobic solvent is usually used as the organic solvent. Examples of such a solvent include hydrocarbon solvents such as toluene and xylene, halogenated hydrocarbon solvents such as chloroform, ether solvents such as dioxane, diethyl ether and ethylene glycol dimethyl ether, and glycol solvents such as ethylene glycol and propylene glycol. And alcohol solvents such as propylene glycol monomethyl ether, ketone solvents such as methyl ethyl ketone and methyl isobutyl ketone, ester solvents such as ethyl acetate and amyl acetate, and mixtures of two or more of these. Among them, a solvent whose boiling point is lower than or equal to the boiling point of water or a solvent which azeotropes with water and which separates from water when mixed with water is preferred. The amount of the organic solvent based on the phenol-aldehyde resin is usually about 0.1 to 20 times by weight, preferably 1 to 20 times.
It is about 10 times by weight.

In the present invention, the above-mentioned crude phenol-aldehyde resin is used, but when an alkali is applied thereto in the presence of water, the phenol-aldehyde resin is transferred to the aqueous layer. The kind of the alkali used is not particularly limited, but is, for example, an alkali metal hydroxide such as lithium hydroxide, sodium hydroxide, or potassium hydroxide, or an alkali metal carbonate such as sodium carbonate, potassium carbonate, or potassium hydrogen carbonate. And the like. Among them, sodium hydroxide, potassium hydroxide and the like are preferably used.

The amount of the alkali to act is preferably an amount sufficient to transfer the phenol-aldehyde resin to the aqueous layer.
It is usually at least equivalent, preferably about 1 to 2 equivalents. Water is preferably present in an amount sufficient to transfer the phenol-aldehyde resin to the aqueous layer, and is usually about 0.1 to 10 times the weight of the phenol-aldehyde resin, and more preferably 0.5 to 10 times. It is about 5 times the weight. Here, when the crude phenol-aldehyde resin does not contain a sufficient amount of water, it is preferable to act on an alkaline aqueous solution. Good, but it is preferable to use an alkali. The alkali acts at a temperature of usually about 0 to 60 ° C, preferably about 40 to 60 ° C.

In the present invention, the organic solvent layer is separated after the phenol-aldehyde resin is transferred to the aqueous layer. The method for separating the organic solvent layer includes, for example, liquid separation, decantation, and distillation. Method.

After separating the organic solvent layer, the resulting aqueous layer is added to an acid solution to precipitate a phenol-aldehyde resin. The type of acid is not particularly limited, and aqueous solutions such as hydrochloric acid and sulfuric acid are usually used. Is done. The amount of the acid used is such that the pH of the slurry after precipitation becomes 7 or less, preferably about 1 to 4. The concentration of the aqueous solution of the acid used is preferably a value in consideration of the stirring resistance of the precipitated slurry, and the total amount of water at the time of precipitation is about 1 to 20 times the weight of the phenol-aldehyde resin. Preferably 1 to 10
It is prepared so as to be about weight-fold.

As a method for removing the resin from the slurry obtained by the precipitation, filtration, decantation and the like can be mentioned, but filtration is preferably employed. The resin taken out may be dried if necessary after washing with water, or may be used as it is as a raw material in the next step.

[0015]

According to the present invention, in producing a purified phenol-aldehyde resin from a crude phenol-aldehyde resin containing an organic solvent and a phenol-aldehyde resin, the organic solvent is completely separated and the solvent is re-purified. Thus, the desired product can be obtained very easily with good yield.

[0016]

EXAMPLES Hereinafter, the present invention will be specifically described with reference to Examples and Comparative Examples, but the present invention is not limited to these Examples.

Reference Example 1 3 L equipped with a stirrer, thermometer, separation tube and cooler
In a four-necked flask, 312.1 g of 2-t-butyl-5-methylphenol, 4-hydroxybenzaldehyde 1
22.1 g, 1.236 g of p-toluenesulfonic acid, and 303.9 g of toluene were charged and heated to 114 ° C.
Toluene-water was azeotropically distilled at 112 to 114 ° C., water was separated in a separation tube, and toluene was kept in the system for 4 hours while being returned to the system to obtain a crude phenol-aldehyde resin.

EXAMPLE The crude phenol of the 3 L four-necked flask obtained in Reference Example 1 was prepared.
To the aldehyde resin, 1425 g of water and 239.7 g of a 48.5% aqueous sodium hydroxide solution were added using a dropping funnel, and the mixture was stirred at 80 ° C. for 0.5 hour to cause an alkali to act, whereby the phenol-aldehyde resin was added to the aqueous layer. Migrated. Next, the temperature is raised to 100 ° C under normal pressure,
Reflux and liquid separation were performed using a Stark apparatus, and only toluene was distilled off. The obtained aqueous solution is kept at 80 ° C.
When the solution was added to 1572.7 g of a 10% aqueous sulfuric acid solution in a 5 L separable flask kept at 0 ° C. over 1 hour under a nitrogen stream, the resin was precipitated to form a slurry. The precipitate was collected by filtration, washed three times with 1700 g of water, and dried under reduced pressure to obtain 397.0 g of a purified phenol-aldehyde resin as an orange powder (yield 9 based on the theoretical amount).
5.4%).

Reference Example 2 According to Reference Example 1, 2-t was placed in a 3 L separable flask.
624.1 g of 4-butyl-5-methylphenol, 244.2 g of 4-hydroxybenzaldehyde, 2.473 g of p-toluenesulfonic acid, and 607.8 g of toluene were reacted at a temperature of 114 ° C. for 5 hours and reacted to obtain crude phenol-aldehyde. A resin was obtained.

Comparative Example The crude phenol-aldehyde resin obtained in Reference Example 2
After neutralizing by charging 1.07 g of an 8.5% aqueous sodium hydroxide solution, 607.8 g of n-hexane was dropped into a system kept at 70 to 80 ° C. while paying attention to scaling. It became a slurry. The precipitate was collected by filtration, washed three times with 1500 g of water, and dried under reduced pressure to obtain 740.2 g of a purified phenol-aldehyde resin as an orange powder (yield 88.9 based on the theoretical amount).
%). The yield is lower than in the examples. Further, since the solvent after the resin filtration is a mixture of toluene and n-hexane, it is necessary to separate them by means such as distillation for the next use.

Claims (6)

[Claims] 1. A crude phenol-aldehyde resin containing an organic solvent and a phenol-aldehyde resin is purified from purified phenol-aldehyde resin.
In producing an aldehyde resin, the crude phenol-
The alkali is allowed to act on the aldehyde resin in the presence of water to transfer the phenol-aldehyde resin to the aqueous layer, then the aqueous layer and the organic solvent layer are separated, and then the aqueous layer is added to the acid solution to precipitate the phenol-aldehyde resin. A method for producing a purified phenol-aldehyde resin. 2. An organic solvent comprising a hydrocarbon solvent, a halogenated hydrocarbon solvent, an ether solvent, a glycol solvent,
2. The method according to claim 1, wherein the method is at least one selected from an alkoxy alcohol solvent, a ketone solvent, and an ester solvent. (3) an alkali metal hydroxide as an alkali;
3. The method according to claim 1, wherein at least one selected from alkali metal carbonates is used. 4. The method according to claim 1, wherein the aqueous layer and the organic solvent layer are separated by a liquid separation method, a decantation method or a distillation method. 5. The method according to claim 1, wherein the acid solution is an aqueous solution of hydrochloric acid or sulfuric acid. 6. A phenol-aldehyde resin represented by the general formula (1): ## STR1 ## (Wherein, R is independently a hydrogen atom, a halogen atom, a hydrocarbon group having 1 to 6 carbon atoms or an alkoxy group having 1 to 6 carbon atoms, and R ′ is a hydrogen atom or a hydrocarbon group having 1 to 6 carbon atoms. , A, b and c each independently represent a number of 0 to 2, and m and n each independently represent a number of 0 to 5 on average). The method according to claim 1.