JPS62174218A - Production of phenolic resin - Google Patents

Abstract

PURPOSE:To facilitate the formation of a high-purity phonolic resin suitable for e.g., electronic material, by reacting a phenol with a formaldehyde in the presence of a catalyst and concentrating the reaction mixture by dehydration while simultaneously blowing steam and N2 gas thereinto. CONSTITUTION:A phenol (e.g., phenol) and a formaldehyde (e.g., HCHO) are fed together with an acid or alkali catalyst (e.g., aqueous hydrogen chloride solution) to batchwise reaction kettle 1 equipped with a jacket 2 for heating and cooling and reacted by heating with agitation. The pressure in the kettle is decreased to 100-200Torr by a vacuum pump 5 and the solution temperature in the kettle 1 is kept at 10 deg.C or above Steam from a steam inlet pipe 6 and N2 gas from a N2 gas inlet 7 are blown simultaneously into the reaction mixture at a steam to N2 ratio of 1:1-2, and the vaporized water and unreacted matter are condensed by cooling in a condenser 3. The condensate is recovered in a condensate receiver 4. Thus a high0purity phenol resin of an unreacted matter content >=1,000ppm is obtained.

Description

[Detailed description of the invention] [Industrial application field] The present invention relates to a method for producing phenolic resins.

[Conventional technology]

Generally, in the process of manufacturing phenol resin, after synthesizing phenol and formaldehyde, there is a dehydration and concentration process to remove water remaining in the reaction system and unreacted monomers. It is being done. In order to reduce the residual amount, a steam distillation method in which water vapor is blown is also used. (Kamei Sanbe “Chemical Machinery Theory and Calculation JP 197. Sangyo Tosho 196
3゜etc.) [Problems to be solved by the invention] Among the above methods, the vacuum evaporation operation is used to shorten the time required to remove unreacted monomers in the synthesis source solution and to further reduce the residual amount. This method is an improvement on the normal pressure evaporation operation. However, when the amount of residual monomer is on the order of ioooppm or less, such as in the case of phenolic resins used in electronic materials, it is impossible to remove the monomer by vacuum evaporation. On the other hand, in the steam distillation method, 1oooppm
However, there is a problem that the amount of waste liquid containing phenol, formaldehyde, etc. discharged outside the reaction system increases significantly, and the pollution treatment load increases. The present invention provides a method for producing phenolic resin that solves the problems.

[Means for solving problems]

The method for producing phenolic resins of the present invention involves reacting phenols and formaldehyde under an acidic or alkaline catalyst, and then simultaneously blowing water vapor and nitrogen gas when removing water and unreacted monomers remaining in the reaction system. It is characterized by dehydration and concentration.

When dehydrating and concentrating in the present invention, it is preferable that the synthesis kettle is equipped with a jacket or a coil, a heat medium is passed through it, and the liquid temperature in the synthesis kettle is heated and stirred to 120° C. or higher.

FIG. 1 shows a flow sheet of an example of an apparatus for the production method of the present invention.

A batch type synthesis reactor 1 equipped with a stirring device and a heating and cooling jacket 2 is provided with a steam blowing pipe 6 and a nitrogen gas blowing pipe 7 equipped with a flow rate regulating device. The synthetic stock solution that has been synthesized in this synthesis pot is heated, and the pressure inside the synthesis pot is reduced by the vacuum pump 5. At this time, water vapor and nitrogen gas are blown in to perform dehydration and concentration by vacuum evaporation operation. Evaporated water and unreacted substances are stored in condenser 3.
The condensate is cooled and condensed within the condenser, and collected in the condenser condensate receiving tank.

The amounts of water vapor and nitrogen gas blown are appropriately selected depending on the capacity of the synthesis vessel. The ratio of water vapor and nitrogen gas is preferably 1:1 to 1:2; outside this range, the amount of waste liquid increases and phenol condenses in the condenser, which is not preferred. Also, the degree of decompression should be higher, but it is usually 100~
A condition of 200 Torr is adopted.

[Effect]

As is well known, if you want to remove a volatile impurity with a higher boiling point than a target substance with a higher boiling point,
Steam distillation is usually used.

This steam distillation method applies the equilibrium theory of vapor pressure, as explained by Raoult's law for ideal solutions and Henry's law for non-ideal solutions. By reducing the partial pressure of the distillate and lowering the distillation temperature, impurities can be efficiently removed.

In the present invention, in order to lower the partial pressure of phenol, water vapor and nitrogen gas are used in combination to efficiently remove phenol. The reason why water vapor and nitrogen gas are used together in the present invention is as follows.

That is, when only water vapor is used, as mentioned above, an increase in waste water treatment load becomes a problem, whereas when only nitrogen gas is used, a decrease in condenser efficiency becomes a problem. In other words, the phenol to be removed has a high freezing point of 40°C, so if only nitrogen gas is used, it will solidify immediately after condensing on the heat transfer surface of the condenser, reducing the heat transfer efficiency of the condenser and eventually causing blockage. There is a problem with this. If a small amount of water vapor is blown in together with nitrogen gas, the condensate in the condenser becomes a mixture of water vapor and phenol, and does not coagulate. Therefore, impurities such as phenol can be removed without impairing condenser efficiency.

Figure 2 shows the changes in the amount of phenol remaining in the phenol resin during vacuum evaporation, steam distillation, nitrogen distillation, and steam/nitrogen distillation.

■ means no blowing, ■ means water vapor (100 g/Hr) ■ means nitrogen gas (100 g/Hr) ■ means water vapor (30 g
/Hr) and nitrogen gas (60g/Hr).

In Figure 2, the rate of phenol reduction in the second half of nitrogen distillation (■) is slow because the heat transfer surface of the condenser is covered with condensed phenol, which mixes with the seal water of the vacuum pump, increasing the degree of vacuum. . Furthermore, although there is no difference in the rate of decrease between ■ and ■, the amount of waste liquid containing phenol is approximately three times greater in ■ than in ■.

〔Example〕

EXAMPLES Hereinafter, the present invention will be explained using Examples, but the scope of the present invention is not limited by these Examples.

Example 3 Into a 0ON reaction vessel, 120 kg of phenol, 700 kg of formalin (37% formaldehyde aqueous solution), 10%
Add 0.4 kg of hydrochloric acid aqueous solution and add 100 kg while stirring.
When the reaction mixture became cloudy, dehydration and concentration was started under normal pressure. When the temperature of the reaction mixture reached 130 degrees, the degree of vacuum was lowered to 200 Torr using a vacuum pump, and the pressure was reduced to 3 kg/
cdG water vapor 3 pupils/Fl r %pressure 5kg/a
Nitrogen gas of dG was blown at 5 k/hr, and dehydration and concentration was continued for 3 hours.

The resin obtained above had the following properties. Softening point: 83°C, shell flow: 50%, remaining unreacted phenol: 400ppm.

In addition, the amount of waste liquid containing phenol is 30% compared to the steam method.
There weren't many.

〔Effect of the invention〕

According to the production method of the present invention, the content of unreacted substances, etc. in the phenol resin can be easily reduced to 11,000 pp or less, and high purity products for use in electronic materials etc. can be produced. Furthermore, since phenol coagulation does not occur on the heat transfer surface of the condenser, the efficiency of the condenser is not impaired, making it possible to reduce equipment capacity and equipment maintenance time. Furthermore, according to the present invention, it is possible to reduce the amount of waste liquid containing phenols. As described above, the present invention has great value in terms of industrial, economical and pollution control aspects.

[Brief explanation of drawings]

FIG. 1 is a flow sheet of an apparatus for producing phenolic resin by the production method according to the present invention. FIG. 2 is a graph showing the change in the amount of residual phenol during the distillation operation. Explanation of symbols 1 Reaction vessel 2 Heating and cooling jacket 3 Condenser 4 Condenser condensate receiving tank 5 Vacuum pump 6 Steam blowing pipe 7 Nitrogen gas blowing pipe

Claims (1)

[Claims] 1. Phenol, which is characterized by reacting phenols and formaldehyde under an acidic or alkaline catalyst, and then removing water and unreacted monomers remaining in the reaction system by simultaneously blowing water vapor and nitrogen gas for dehydration and concentration. Method of manufacturing resin.