SU49220A1 - A method of making artificial resin - Google Patents

Description

CH (OH) - CH (OH) h CH3 - CH - CH To obtain these condensation products with formaldehyde, the following polyatomic can be taken

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alcohols: glycol (product, glycol-formal condensation), glycerin (glycerol-formal condensation product).

pentaerythritol (condensation product pentaerythritol-diformacetal), sorbitol and mannitol (condensation products sorbitol and mannitol-triformacetal).

These solid or liquid products can be introduced directly or as aqueous or alcoholic solutions into the initial syrup-like condensation products of urea, thiourea, dicyandiamide, or their derivatives; with formaldehyde, in the amount of 5-30%, and they can be added before or after the distillation of water, also in the course of condensation. The resulting mixtures are polymerized in the usual way in the presence or absence of a curing accelerator at a temperature of 40-80 ° to obtain a transparent elastic solid mass resembling glass in appearance.

Example 1. A mixture of 420 g of 38 o / o formalin and 5.4 g of 25% ammonia with a pH of 7.6 to 7.8 is heated on a boiling water bath for half an hour, after which 60 g are added to the hot solution. urea and heat the mixture again in the continuation of 20-40 minutes. Then, 60 g of alcohol and 60 g of urea are introduced into the reaction mixture and are heated together at 80 until the concentration of hydrogen ions in the mixture is pH 4.6 - 5.6. At the end of the condensation, 25 g of glycerol-formacetal (t. To 190-195 °) is added to the reaction product, all is thoroughly mixed and placed in a vacuum bottle and evacuated at 60-70 ° and residual pressure of 50-70 mm.

The resulting hot syrup is poured into porcelain forms and polymerized, first at 35-50 ° and then at 55-60 °, until solid, elastic, transparent products are obtained.

Example 2. 100 g of urea is dissolved in 400 g of neutralized 30%

Formalin, 20 g of condensation product of glycol with formaldehyde (t. 190 °) are added to the solution and the solution is heated in a water bath for an hour. Then 1.2 g of formic acid are added to the mixture, 24 g of thiourea and heated again for 2 hours. The product obtained is evaporated in a vacuum drier and polymerized in forms according to the indication of Example D, the pH of the evaporated resin is 4.2-5.0.

Example 3. 100 g of dicyandiamide are dissolved in 130 g of 38% formalin, 6 2 2 of calcium chloride is added to the resulting solution and heated in a water bath under reflux for 1 hour with constant stirring. After 1 hour, the temperature of the reaction mixture is adjusted to 100 and condensation is carried out at this temperature for 3.5-4 hours. To the resulting condensation product, which is: a colorless thick liquid, add 12 g of penta-eddirtrite deformal acetal (mp. 50 °), mix everything well, pour the syrup into forms and polymerize at 55-60 ° for 10-12 days; pH of the condensation product is 3.6-4.2.

The subject matter of the invention.

A method of making artificial resins from condensation products of urea, thiourea, dicyandiamide or their derivatives with formaldehyde, characterized in that from the condensation process of the above substances or from their initial condensation products, from 5 to 30% cyclic acetals obtained by reacting polyhydric alcohols with formaldehyde are introduced in the presence of an acid catalyst.