RU2841747C1 - Rust solvent - Google Patents

Abstract

FIELD: chemistry.

SUBSTANCE: invention relates to chemical agents used for treating metal surfaces and for preparing metal surfaces for painting. Rust solvent contains, as a base, an oxyacid in the form of orthophosphoric or oxalic acid and additionally an organic solvent or a mixture of a water-soluble organic solvent and water in ratio of 1:0.2, corrosion inhibitor – inert inhibitors based on five- and/or six-member nitrogen-containing heterocycles, surfactants, mainly nonionic, and zinc oxide. Components are stirred at room temperature and held for 2 hours, with the following ratio, wt.%: oxyacid 32.5-38.5; solvent or mixture of water-soluble organic solvent and water 63.4-55.8; surfactant 0.5-1.0; corrosion inhibitor 0.3-0.9; zinc oxide 3.3-3.8. Rust converter enables to prepare the treated surface for painting, where it is sufficient to wash it off with water or perform dry cleaning and apply paint coating after 30 minutes.

EFFECT: invention reduces labour input in preparing metal surfaces for applying lacquer coatings and cuts the drying time of the metal surface before painting.

1 cl, 2 tbl, 16 ex

Description

The invention relates to chemical agents, namely chemical substances that can be used for treating metal surfaces and for preparing a metal surface for painting.

An inhibited rust modifier is known, containing orthophosphoric acid, zinc oxide, sodium metasilicate, sodium hexametaphosphate, calcium hypophosphite, tannin, yellow blood salt, red blood salt, polyvinyl acetate dispersion and distilled water (patent BY 16127, C 23F 11/173, C 23F 11/18). This substance is intended for preparing ferrous metal surfaces damaged by corrosion for painting, helping to increase the service life of paint and polymer coatings.

The disadvantage of this rust modifier is the complex composition of the original components, as well as the possibility of using this substance on products made of ferrous metals only. In some cases, a single application of the rust modifier is not enough, which is why it is necessary to re-use it to remove rust and apply paint and varnish coatings to the metal surface after 24 hours.

A rust converter is known that contains orthophosphoric acid, starch and water as an active base (patent RU, C23F 1/14, C23G 1/02, 2009). The proposed agent is intended for removing corrosion products from the surface of ferrous and non-ferrous metals.

The disadvantage of this invention is the complex technology for preparing the initial composition of the rust converter.

The rust converter "Promkor" is known, which we chose as a prototype, is a composition based on orthophosphoric acid and a complex of converters (TU No. 2388-018-59423693-2014). The chemical composition is designed to firmly bind particles of metal subject to corrosion with a thickness of no more than 100 microns.

The disadvantage of the declared rust converter is that its use is associated with labor-intensive preparation of the metal surface, where the surface must first be degreased, then mechanically cleaned from dust, dirt and corrosion products. As well as a long drying period and application of paint and varnish coatings only 24 hours after metal restoration.

The technical problem, which the claimed invention is aimed at solving, is the development of an effective rust converter composition with the following technical result: reduction of labor costs for preparing metal surfaces for applying paint and varnish coatings and reduction of drying time before their application. This agent allows preparing the treated surface for painting, simply rinsing with water or dry cleaning (for example, with a brush, swab) and applying paint and varnish coatings after 30 minutes.

The specified technical result is achieved in that the rust converter contains orthophosphoric acid or oxalic acid as a base and additionally a water-soluble organic solvent or a mixture of a water-soluble organic solvent and water, and as a corrosion inhibitor - inert inhibitors based on five- and (or) six-membered nitrogen-containing heterocycles, mainly non-ionic surfactants (surfactants), zinc oxide obtained by mixing an oxyacid, zinc oxide, a surfactant and a corrosion inhibitor in a water-soluble organic solvent or a mixture of a water-soluble organic solvent and water in a ratio of 1: 0.2 at room temperature and holding the mixture for 2 hours with the following ratio of components, wt.%: oxyacid 32.5 - 38.5; solvent or a mixture of a water-soluble organic solvent and water 63.4 - 55.8; surfactant 0.5 - 1.0; corrosion inhibitor 0.3 - 0.9; zinc oxide 3.3 - 3.8.

The main active component of the rust converter is oxyacids - orthophosphoric acid (85%) or oxalic acid, the solvent is a water-soluble organic solvent or a mixture of a water-soluble organic solvent and water, and the corrosion inhibitor is an inert inhibitor based on five- and (or) six-membered nitrogen-containing heterocycles. In most variants, the surfactants are nonionic surfactants, and it is also possible to use surfactants that exhibit inhibitory ability, which makes it possible to replace the addition of surfactants and a corrosion inhibitor.

The rust converter is obtained as follows.

The calculated amount of initial reagents and solvent are loaded into a flask equipped with a mechanical stirrer. Stir intensively at room temperature and the finished mass can be applied to the surface to be treated. The declared rust converter can be washed off with water or dry cleaned and paint and varnish coatings can be applied after 30 minutes.

Examples of implementation of the invention.

Example 1 (according to the invention). The initial components: orthophosphoric acid (36.5 wt.%), zinc oxide (3.8 wt.%), - lignosulfonate (works as a surfactant and corrosion inhibitor) in an amount of 0.5 wt.% in acetone (59.2 wt.%) are stirred at room temperature, the mixture is kept for 2 hours at room temperature, and used as intended.

Examples 2. Repeat example 1, using oxalic acid instead of orthophosphoric acid.

Example 3. Example 1 is repeated, using as a solvent a mixture of a water-soluble organic solvent (acetone) and water in a ratio of 1:0.2.

Example 4. Example 2 is repeated, using as a solvent a mixture of a water-soluble organic solvent (acetone) and water in a ratio of 1:0.2.

Example 5. The initial components: orthophosphoric acid (34.5 wt.%), zinc oxide (3.3 wt.%), surfactant - neonol (0.2 wt.%) and inhibitor derivative of imidazoline-4 (0.5 wt.%) in methanol (61.5 wt.%) are stirred at room temperature. The mixture is kept for 2 hours and used as intended.

Examples 6. Repeat example 5, using oxalic acid instead of orthophosphoric acid.

Example 7. Example 5 is repeated, using as a solvent a mixture of a water-soluble organic solvent (methanol) and water in a ratio of 1:0.2.

Example 8. Example 6 is repeated, using as a solvent a mixture of a water-soluble organic solvent (methanol) and water in a ratio of 1:0.2.

Example 9. The starting components: orthophosphoric acid (36.5 wt.%), zinc oxide (3.8 wt.%), surfactant - neonol (0.5 wt.%) and inhibitor - derivative of unsymmetrical triazine (0.5 wt.%) in isopropanol (58.7 wt.%) are stirred at room temperature, the mixture is kept for 2 hours and used as intended.

Example 10. Repeat example 9, using oxalic acid instead of orthophosphoric acid.

Example 11. Example 9 is repeated, using as a solvent a mixture of a water-soluble organic solvent (isopropanol) and water in a ratio of 1:0.2.

Example 12. Example 10 is repeated, using as a solvent a mixture of a water-soluble organic solvent (isopropanol) and water in a ratio of 1:0.2.

Example 13. The initial components: orthophosphoric acid (32.5 wt.%), zinc oxide (3.8 wt.%), surfactant - OS-20 (0.5 wt.%) and inhibitor derivative of imidazoline-4 (0.5 wt.%) in acetone (62.7 wt.%) are mixed, the mixture is kept for 2 hours at room temperature and used as intended.

Example 14. Repeat example 13, using oxalic acid instead of orthophosphoric acid.

Example 15. Example 13 is repeated, using as a solvent a mixture of a water-soluble organic solvent (acetone) and water in a ratio of 1:0.2.

Example 16. Example 13 is repeated, using as a solvent a mixture of a water-soluble organic solvent (isopropanol) and water in a ratio of 1:0.2.

Testing of the claimed rust converter.

To obtain a comparative assessment of the efficiency of the declared samples of rust converters, namely in accordance with GOST 15140-78, corrosion resistance and strength control of metal surfaces were carried out in model solutions. The lattice cut method was used.

The declared sample of rust converter was applied to two plates measuring 70x150x1.5 mm made of St-20 steel (GOST 16523-70). The rust layer was 50-90 µm. After treatment with the declared sample of rust converter, the metal plates were kept in a model environment (GOST 30662-99) for 120 and 240 hours. The measurement results are given in Tables 1 and 2.

To determine the drying time, a visual determination was made based on the quality of the cleaned surface, and the optimal time was found to be no more than 30 minutes.

Thus, the claimed compounds have protective properties, and the results obtained indicate the potential of using rust converters.

Claims (1)

A rust converter, characterized in that it contains orthophosphoric acid or oxalic acid as a base and additionally a water-soluble organic solvent or a mixture of a water-soluble organic solvent and water, and as a corrosion inhibitor - inert inhibitors based on five- and/or six-membered nitrogen-containing heterocycles, surfactants (surfactants), mainly non-ionic, and zinc oxide, wherein it is obtained by mixing the said oxyacid, zinc oxide, surfactant and corrosion inhibitor in a water-soluble organic solvent or a mixture of a water-soluble organic solvent and water in a ratio of 1:0.2 at room temperature and holding the mixture for 2 hours, with the following ratio of components, wt.%: oxyacid 32.5-38.5; solvent or a mixture of a water-soluble organic solvent and water 63.4-55.8; surfactant 0.5-1.0; corrosion inhibitor 0.3-0.9; zinc oxide 3.3-3.8.