JPS61243816A - Production of amino resin - Google Patents

Abstract

PURPOSE:To produce an amino resin having a predetermined degree of condensation within a short time, by bringing a vapor produced in the production of an amino resin into countercurrent contact with an oil formed by condensing the vapor and subjecting the condensate to oil/water separation and recirculating this oil into the reactor. CONSTITUTION:Normal- and/or iso-butyl alcohols, formaldehyde, melamine and/or urea and/or benzoguanamine are fed to a reaction vessel 1, and the production of an amino resin is started by heating with a heating source 8. A vapor mainly consisting of said alcohol and water is fed through a gas/liquid contact apparatus 7 and a vapor pipe 2 to a condenser 3 and condensed. This condensate is led through a pipe 4 to an oil/water separator 5, where it is separated into an oil layer based on the alcohol and a water layer. This water layer is discharged out of the system through a pipe 10, and the oil layer 6 is led through a pipe 6 to the contact apparatus 7, where it is brought into gas/liquid contact with the vapor from the reaction vessel 1, and the oil is recirculated into the reactor 1.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application This invention relates to a method for producing amino resins.

BACKGROUND OF THE INVENTION Amino resins are inexpensive and have excellent performance as crosslinking agents for thermosetting resins, so they are useful resins that are widely used mainly for crosslinking resins such as thermosetting alkyd resins and acrylic resins.

The conventional method for producing this resin is normal and/or inobutyl alcohol, formaldehyde.

and melamine and/or urea and/or benzoguanamine in a specific molar ratio in the presence of an acid catalyst.

The methylolation and butylation condensation reactions are carried out in a boiling state, and the resulting water is azeotroped with butyl alcohol without heating, and then condensed in a condenser (2) connected to a reactor (1) as shown in FIG.

Water was separated and discharged using an oil-water separator (1), and the butyl alcohol in the resulting oil layer was recycled back to the reactor.

Problems to be Solved by the Invention However, in this method, even if two layers are separated using an oil-water separator, the water content in the oil layer (butyl alcohol) determined by the temperature is relatively high. Since it is not possible to reduce the water content, reflux liquid with a high water concentration is constantly circulated through the reactor.

There is no problem as long as the water concentration in the reaction solution is higher than the water concentration in the reflux solution, but as dehydration progresses and the water concentration decreases, the dehydration rate decreases markedly, and eventually the water concentration in the reaction solution reaches the reflux solution. Equilibrium is reached due to the water content. For this reason, the progress of the condensation reaction is significantly inhibited, and a long time is required to reach a predetermined degree of condensation.

Means for Solving the Problems The inventor of the present invention has conducted extensive research to solve the above-mentioned problems, and has completed the present invention.

That is, the method for producing an amino resin of the present invention is as follows.

When producing an amino resin by heating and reacting normal and/or isobutyl alcohol, formaldehyde, and melamine and/or urea and/or benzoguanamine in the presence of an acid catalyst as raw materials.

This method of producing an amino resin is characterized in that steam generated in a reactor and an oil obtained by condensing the steam and separating oil and water are brought into countercurrent contact and refluxed to the reactor.

Specific examples of the method of bringing the steam generated during the production of the amino resin according to the present invention into countercurrent contact with the oil component obtained by condensing the steam and separating the oil and water include installing a plate column, wet wall culture, etc., and bringing the gas-liquid into contact with each other. Countercurrent contact can be achieved by spraying oil onto the steam piping.

Drawing description The present invention will be explained with reference to the drawings.

FIG. 1 shows a flow diagram of an embodiment of the method for producing an amino resin of the present invention.

In FIG. 1, the solution in the reactor (2) is heated by a heating source (2) to become a vapor mainly composed of butyl alcohol and water, which passes through a gas-liquid contactor and a steam conduit (2) and is condensed in a condenser (2). The condensate passes through conduit (2) and is separated into an oil layer containing butyl alcohol as the main component and an aqueous layer containing water as the main component in oil/water separator (2).

The aqueous layer is discharged out of the system through conduit O.

The oil layer passes through the conduit■ and is transferred to the reactor by the gas-liquid contact device■.
After making gas-liquid contact with the vapor from -, it is refluxed to the reactor.

In the conventional method shown in Figure 2, the oil layer from the oil-water separator is piped into
1 and is refluxed to the reactor without any gas-liquid contact as shown in FIG.

Effects of the Invention The advantage of producing an amino resin according to the present invention is that the vapor at the outlet of one reactor is brought into gas-liquid contact with the reflux liquid, which still contains a considerable amount of water even if water is separated into two layers, into one reactor. The water concentration in the circulating reflux liquid decreases and the water concentration in the solution in the reactor does not reach equilibrium at a relatively high level as in the conventional method, which is much more effective than in the conventional method. This is because the water concentration in the solution inside the reactor decreases.

Therefore, the progress of the condensation reaction is accelerated and a predetermined degree of condensation can be reached in a short time.

Example The present invention will be specifically explained below using examples.

[Example 1] Isobutyl alcohol 1628kp and 37% formalin 1946° were placed in a 5-volume reactor using the method shown in Figure 1.
Melamine 504kl? , 9 was added to the acid catalyst 2.

2kl of 250yu/h as a heating source? A butylated methylol melamine resin was produced using /ffl.G steam. Four hours after starting reflux, the predetermined condensation level 2 was reached. At this time, a packed tower filled with →→ inch Raschig rings to a height of 1 m was used as a gas-liquid contact device.

[Example 2] In a reactor with a capacity of 5 d, 1628 kg of n-butyl alcohol and 194 % formalin were added by the method shown in Fig. 1.
6 to 9. Melamine 378kg, benzoguanamine 280kg
KlF, 9 was added to the acid catalyst 2 as a heating source.

A butylated methylolmelamine/benzoguanamine cocondensation resin was produced using 250 kg/H 2S/d.q steam. Three hours after starting reflux, a predetermined degree of condensation was reached. At this time, a 1 m high wet wall culture medium was used as a gas-liquid contact device.

[Example 3] In a reactor with a capacity of 5 d, 2368 kg of n-butanol, 1298 kg of 37-thiformin, 480 kg of urea and 9.0 kg of urea were placed in a reactor with a capacity of 5 d using the method shown in FIG. Inject 2 kg of acid catalyst and use it as a heating source
A butylated methylol urea resin was produced using 2 kg/ffl G steam.

Seven hours after starting reflux, a predetermined degree of condensation was reached.

At this time, a three-stage lift tray (manufactured by Kansai Kagaku Kikai (I)) was used as a gas-liquid contact device.

[Example 4] According to the method shown in Fig. 1, in a reactor with a capacity of 51, 1776 yen of isobutyl alcohol, 9.37 yenol of thiformin, 1848 yuan of thiformalin, and 360 yen of urea were added with 9.37 yuan of thiformin. 228 kg of melamine, 9 in acid catalyst 2, 250 in 9/H as a heating source, 2 in 9/ff1-
A butylated methylol urea/melamine cocondensation resin was produced using G steam. A predetermined degree of condensation was reached 6 hours after the start of reflux. At this time, instead of a gas-liquid contact device,
Gas-liquid contact was carried out by pressurizing the reflux liquid with a pump and spraying it onto the steam piping using a spray nozzle.

[Comparative Example 1] When a butylated methylolmelamine resin was produced by the method shown in Figure 2 under the same conditions as Example 1, the degree of condensation progressed slowly for 8 hours because the water concentration in the reaction solution decreased slowly. Afterwards, a predetermined degree of condensation was reached.

[Comparative Example 2] A butylated methylolmelamine/benzoguanamine co-condensation resin was produced by the method shown in FIG. 2 under the same conditions as in Example 2, and a predetermined degree of condensation was reached after 5 hours.

[Comparative Example 3] A butylated methylol urea resin was produced by the method shown in FIG. 2 under the same conditions as in Example 3, and a predetermined degree of condensation was reached after 15 hours.

[Comparative Example 4] A butylated methylol urea melamine cocondensation resin was produced by the method shown in FIG. 2 under the same conditions as in Example 4, and a predetermined degree of condensation was reached after 11 hours.

[Brief explanation of drawings]

FIG. 1 shows a flowchart of one embodiment of the method for producing an amino resin of the present invention. FIG. 2 shows a conventional method for producing an amino resin using a flow diagram. ■ Reactor ■ Steam conduit ■ Condenser ■ Condensate conduit ■ Oil-water separator ■ Reflux liquid conduit ■ Gas-liquid welding device ■ Heating source conduit ■ Cooling water conduit ■ Distillate water conduit Patent applicant Mitsui Toatsu Chemical Co., Ltd. 1 Figure 2

Claims (1)

[Claims] When producing amino resin by heating and reacting normal and/or isobutyl alcohol, formaldehyde, and melamine and/or urea and/or benzoguanamine in the presence of an acid catalyst as raw materials, the vapor generated in the reactor and the vapor are condensed. A method for producing an amino resin, which comprises bringing the oil obtained by separating oil and water into countercurrent contact and refluxing it into a reactor.