SU59318A1 - Method of making paints - Google Patents

Description

This invention relates to a process for the manufacture of paints based on phenol aldehyde resins and pigments. This method of producing film-forming paint coatings is reduced to making so-called novolac or resole resins. In this case, the process of making these artificial resins is usually carried out with the calculation of the greatest resin formation. The remaining free phenol and formaldehyde are possibly more completely removed from the resin. The resin is then dried and brought to a hard, brittle mass, which is dissolved in an alcohol or other solvent. Resins made in this way are used for paints that can only be applied on a dry surface.

In order to obtain paints that can be applied to the surface under water or on a wet surface, it is proposed to use resinous pox, which is significantly different from the above-mentioned novolac and resole resins.

Initially, the process of their manufacture proceeds by the usual method, i.e., a mixture containing 1 mole of formaldehyde and 2 moles of phenol (but

lupine scheme) or 1 mol of formaldehyde and 1 mol of phenol (rezol scheme) heated to 90-95 °, add with stirring a catalyst (acidic with nosolac, alkaline with resol,); after boiling begins, carefully follow the course of condensation, which is characterized by a distinct mass separation (formation of two layers).

As soon as it happened, the heating is immediately stopped and at the same time the whole mass is cooled to a temperature of 45-50 °, after which the degree of condensation is determined.

For underwater paint, a resinous aqueous solution of incomplete and primary condensation is used, unlike ordinary resin, which contains dioxiphenolmethane, phenol and formaldehyde in the novolac type, and oxybenzyl alcohol, formaldehyde and phenol in the resol solution.

The resinous mass should contain, at noBolac, free phenol from 12 to%, free formaldehyde from 6 to 8%, and at resol, free phenol from 6 to 8%, free formaldehyde at 15 to 18%. If the resin does not respond to the indicated values, the heating is resumed and condensation continues, and if the composition is consistent, the resulting resinous mass is determined and the catalyst is removed from it immediately. This is achieved by washing the separated mass with hot water while thoroughly mixing it. The completeness of washing is determined by the value of PH: when novolak, pH must be equal to 2, and when the resol is 3.5. When washing, it is necessary to avoid introducing an excess of water, since this removes phenol and formaldehyde.

The resinous solution obtained by this method is subjected to evaporation to remove excess moisture from it. When Novolak moisture content should not exceed 8-10%, and when Resole 13-15%.

Various metal oxides, in particular, iron oxide, zinc, lead, chromium, cobalt, titanium, etc., can be used as a pigment for the manufacture of underwater paint.

The pigment in this paint, in addition to its usual purpose, is also used to accelerate the hardening of the applied coating, as a result of which it should be prepared as follows: 3-5% of its weight of Portland cement and 3 -4% purified talc. The resulting mixture is thoroughly mixed and allowed to run on runners until a thin mixture of the same type is obtained.

The resinous base made by the above method is mixed with

harvested pigment, i.e., masking of the pigment with the resin. This operation is carried out by means of a paint mill, in which the mixture is passed until a uniform paint is obtained. The percentage of base to pigment, depending on the purpose of the coating, can vary from 0.3 to 1 part of the pigment to 1 part of the base.

The method of applying paint to the inner surface and under water is nothing different from the usual methods of paint coatings, i.e. it can be carried out as simple (by means of a conventional brush, spatula, etc.) and by mechanically applying paint.

The subject matter of the invention.

A method of making paints based on phenol-aldehyde resins and pigments, characterized in that in order to obtain paints that can be applied to the surface under water and on a wet surface, as a film-forming base, the product of incomplete primary condensation of phenol and aldehyde is used according to Novolach scheme (1 mole of formaldehyde and 2 moles of phenol with an acid catalyst) or according to the rezol scheme (1 mole of formaldehyde and I mole of phenol with an alkaline catalyst) when heated to 90-95 ° and containing free phenol from 12 up to 14%, free formaldehyde from 6 to 8% and water from 8 to 10% (with novolak) or free phenol from 6 to 8%, free formaldehyde from 15 to 18% and water from 13 to 15% (prc resol).