SU62771A1 - The method of producing glue - Google Patents

Description

, „„ ВСЕС0Ш31 й5

A.L. Kozlovsky

METHOD OF OBTAINING ADHESIVE

It was announced on March 25, 1942 under No. 18-42 / 309176 in NKU 5I55

 - "" "For gluing wood, alcohol solutions of phenol-aldehyde resins are applied, as well as their aqueous solutions, which in practice are called emulsions.

The use of alcohol solutions of resins is associated with:

a) with the inevitability of the loss of large quantities of ethyl alcohol; b) with loading of transport by transportation; c) with labor processes of bottling the solution in bottles, capping, weighing and carrying them out of the workshop; d) with the need to always have a stock of crates for the exchange of worn out ones.

The use of "emulsions also has the following disadvantages: a) instability of emulsions during storage; b) the absence, as a rule, of solubility (dilution with water) to the desired concentration.

All these disadvantages are absent in dry water-soluble adhesives based on the products of phenol condensation with aldehydes.

HsjjecTHO already getting the glue by condensing phenol with formaldehyde at a temperature of about 60 ° in the presence of caustic alkali, followed by the introduction of a weak acid into the reaction mixture.

It has been found that if a weak acid is introduced only to a pH of 6.8-7.0 and the mixture is dried, a water-soluble glue is obtained.

Example. In the boiler with a reflux condenser, phenol or phenol fraction, formalin and caustic soda are charged in the corresponding amounts. The latter is pre-dissolved in a small amount (3-6 kg) according to the recipe. After loading these components put in the course of the mixer and give the heating steam into the jacket. When the temperature of the mixture reaches 45 °, the steam is turned off. Due to the heat of reaction, the temperature in the mixture rises to 60 °. By adjusting the supply of heating steam or cold water to the jacket, the temperature of the mixture at 60 ° is maintained for 2.5 hours. After 2.5 hours from the moment the mixture attains a temperature of 60 °, the mixture is cooled to 25 ° with water — into the jacket. Thereafter, lactic, boric or phosphoric acid or phthalic anhydride is introduced into the mixture in amounts that determine the amount. the pH of the reaction mixture is adjusted to 6.8-7.0, after which the liquid is subjected to the substance, for example, by spraying. The resulting dry powder readily dissolves in water. For gluing, one of

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No. 62771-2 -

the above sour g in an amount to determine the pH of the adhesive solution is 2.8-3. The acid (accelerator) is introduced into the glue just before gluing.

The recipe and mode given are basic, but not the only ones. Instead of caustic soda, caustic potash can be used. The amount of forzmalin can vary from 1 to 3 moles per 1 mole of phenol. Instead of these acids, you can take any weak organic acid. Scaling temperatures can be increased by shortening the condensation time.

Instead of spray drying, a combined drying can be applied: first under a deep vacuum, and then on a roller.x.

Subject invention

Claims (2)

1. A method for producing adhesives based on condensation products of phenol or its homologs with formaldehyde at a temperature of about 60 ° in the presence of a strong base as a catalyst, followed by the addition of a weak acid, characterized in that, in order to obtain a dry water-soluble adhesive, an amount sufficient to bring the pH of the reaction mass to 6.8-7.0, after which the latter is dehydrated. 2. A method according to Claim 1, characterized in that 1-3 mole of formaldehyde is taken per mole of phenol or its homolog.