SU759540A1 - Method of preparing alkide resins - Google Patents

Description

The invention relates to methods for alkyd resins.

The process of obtaining polycondensation products is reversible and equilibrium. The duration of such processes is 10-30 hours. ₍ Therefore, effective and complete removal of water / water formed as a result of the reaction makes it possible to shift its course to the stage of formation of the final product and thereby reduce the synthesis time.

A method of producing a polycondensation products, wherein the water of reaction is removed via ,, or- ganic solvent, forming the ^'e with water at a reaction temperature azeotrope [ΐ].

Typically, the reaction temperature of polycondensation is within 150 -, θ 260 ° C. To maintain this reaction temperature, the organic solvent can be loaded only in an amount of no more than 10%, which is not enough to completely remove the reaction water, therefore, the duration of the synthesis increases. .....

The closest in technical essence and the achieved effect is a method for producing alkyd resins by

²

the interaction of phthalic acid anhydride, glycerin / vegetable oil or synthetic fatty acids with continuous azeotropic distillation of water in the presence of a solvent; forming an azeotropic mixture with water, 40–82% of the composition [2].

This method allows you to reduce the process of synthesis of alkyd resins, however, And it is quite long (5.6 hours).

The purpose of the invention is to intensify the process.

This goal is achieved by the fact that in the method of producing alkyd resins by reacting phthalic anhydride / glycerin / vegetable oil or synthetic fatty acids with continuous azeotropic distillation of water in the presence of a solvent that forms an azeotropic mixture with water 40-82% of the composition, after removing 50—

60% of the reaction water is introduced into the reaction mixture, a solvent that forms an azeotropic mixture with water of 25-28% of the composition and the process continues until the water is completely removed.

It is known that the rate of the initial ‘stage of any polycondensation reaction is much greater than at the end. Next 3 759540

Consequently, the amount of released reaction water per unit of time. In the initial stage of the reaction there will be more than in the final. Therefore, applying in the initial stage of the reaction a solvent that forms an azeotropic mixture with a large amount of water, and in the final stages it dissolves,

a mixture of which- * keeps the minimum composition of water, you can reduce the duration of the synthesis of alkyd resins.

The invention is illustrated by the following examples.

Example 1. In the reactor load 172 g of synthetic fatty acids, 124 g of glycerin, 204 g of phthalic anhydride and raise the temperature to 140 ° C. Then xylene is fed continuously to the reactor at a rate of 0.5-1 g / min. Through the system, the separator-separator and the refrigerator are connected to the vacuum system. The temperature is raised to 210-220 ° C. After removing 50–60% of the reaction water, which is 1–1.5 hours in time, instead of xylene, chlorobenzene is fed at the same rate. The duration of the synthesis of 3 hours versus 5.6 hours by a known method. Indicators of the finished resin: acid number <15 mg KOH / g, "" the viscosity of a 50% solution in xylene according to VZ-4 is 150-200 s.

Example 2. Charged to the reactor 230 g of sunflower oil, 95 g of glycerin and spend the ester exchange reaction. Then load 175 g of phthalic anhydride. At a temperature of 140 ° C, nonane is continuously fed at a rate of 0.5-1 g / min. Through the system, the separator-separator and the refrigerator are connected to the vacuum system. The reaction temperature ^of 200-210 C. After removing 50-60% of the reaction water, which in time is 1-1.5 hours, at the same rate fed other solvent - octane. Indicators of the finished resin: acid number 30 mg KOH / g, viscosity of a 50% solution in xylene according to VZ-4 30–70 ° C. The duration of the polycondensation reaction of 3.2 h instead of 5 h by a known method.

The characteristics of the solvents used are presented in the table.

ten

9

Name solvent ---, - Composition azeotrope weight.% Boiling point, ° C pure solvent azeotrope p-xylene 40.0 139.1 94.5 Chlorobenzene 28.4 131,8 90.2 Nonan 82.0 150.7 94.8 Octane 25.5 125.7 8.9,6

Therefore, the use of

15 method of producing alkyd resins by reacting phthalic anhydride ', glycerin, vegetable oil with continuous azeotropic distillation of water in the presence of a solvent, forming

20 azeotropic mixture with water 40-82% of the composition, after removing 50-60% of the reaction water, a solvent is injected into the reaction mixture, which forms 25-28% of the composition with azeotropic mixture,

_ which makes it possible to reduce the duration of the process of obtaining alkyd resins by 1.5–2 times in comparison with the known method.

Claims (1)

Claim 30 Method for producing alkyd resin by reacting phthalic anhydride, glycerin, vegetable oil or synthetic fatty acids with continuous azeotropic effluent water and in the presence of a solvent that forms an azeotropic mixture with water 40-82% of the composition, characterized in that, in order to intensify the process, after removing 50-60% of the reaction water, the solvent is introduced into the reaction mixture, which forms an azeotropic mixture with water 25-28% of the composition and the process continues until the water is completely removed . ν