Method for corroded metal surface protection and recovery

FIELD: chemistry.

SUBSTANCE: invention concerns method of protection and recovery of corroded metal surfaces operating in abrasive wear conditions and aggressive media, e.g. in fertiliser transportation, and can be applied in power-producing, chemical and mining industry for rusted equipment repair. Method involves application of primer layer on metal surface with further drying till aftertack, insulation layer with further drying till aftertack, and external layer with further drying to complete hardening. Primer layer is made of composition including the following components, wt %: 20.0-30.0 of epoxy diane resin with epoxy equivalent weight of 450-500, 15.0-25.0 of Versamid 115 polyamide solidifier, 12.0-25.0 of pigments, 12.0-25.0 of fillers, 2.0-5.0 of amine-containing Cardolite NC 562 solidifier based on 3-n pentadecanylphenol, the rest is organic solvents. Insulation layer is made of composition including the following components, wt %: 20.0-35.0 of epoxy diane resin with epoxy equivalent weight of 450-500, 15.0-30.0 of Versamid 115 polyamide solidifier, 5.0-10.0 of fillers, 10.0-50.0 of micaceous iron ore, 2.0-5.0 of amine-containing Cardolite NC 562 solidifier based on 3-n pentadecanylphenol, 0.8-1.2 of structurising additive, the rest is organic solvents. External layer is made of composition including the following components, wt %: 20.0-40.0 of acrylic or polyether hydroxyl-containing resin, 11.0-22.0 of aliphatic isocyanate solidifier, 10.0-20.0 of pigments, 10.0-40.0 of micaceous iron ore, 5.0-10.0 of fillers, 0.2-0.6 of polysiloxane modified organically, 0.8-1.2 of structurising additive, 0.6-2.4 of aluminum powder, the rest is organic solvents. Composition of external layer includes additionally Metatin Catalyst tin dibutyllaurate in amount of 0.05-0.5 wt % as drying accelerator.

EFFECT: enhanced corrosion resistance of coating.

cl, tbl, 2 ex

The invention relates to the field of coatings on metal surfaces, steel, iron, aluminum, working in conditions of abrasive wear, corrosive environments in the energy, chemical and mining industries.

There is a method to protect and restore corroded metallic surfaces, comprising applying a primer layer on the base composition containing, wt.%:

with subsequent drying "up tack-free surface, applying an insulating layer of a composition containing, in wt.%:

with subsequent drying "up tack-free", causing the outer layer of the following composition, wt.%:

(U.S. Pat. Of the Russian Federation No. 2220995, BI # 1 of 10.01.2004,).

However, this method provides insufficient protective properties of the coating.

Closest to the present invention is the following method to protect and restore corroded metal surfaces: on the fat surface applied consistently primer of the following composition, wt.%:

and after drying it "until tack-free", that is, to the degree 1 according to GOST 19007-73, put insulating layer of the following composition, wt.%:

and then surface dried "up tack-free", will also cover the outer layer of the following composition, wt.%:

then the dried coating to fully cure (patent RF №2304601).

However, this method provides insufficient protective properties of the coating.

The technical result of the invention is to improve the protective properties of the coating.

This technical result is achieved in that in the method of protection and restoration of corroded metallic surfaces, comprising applying a primer layer on the base composition containing epoxy Dianova resin with an epoxy equivalent weight of 450-500, polyamide hardener Versamid 115, pigments, fillers, organic solvents, followed by drying "up tack-free surface, applying an insulating layer of a composition containing epoxy Dianova resin with an epoxy equivalent weight of 450-500, polyamide hardener Versamid 115, fillers, iron oxide, organic solvents, followed by drying "up tack-free", causing the outer layer of the composition containing acrylic or polyester hydroxyl-containing resin, the curing agent is an aliphatic polyisocyanate, pigments, fillers, organically modified polysiloxane, organic solvents, followed by drying to complete curing, priming and insulating layers impose additional aminecontaining compound brand Cardolite NC 562 is based 3-n pentadecanolide, in insulating and outer layers impose additional structuring additive, and in the outer layer further added aluminum powder and iron oxide in the following ratio of components in layers:

in the composition of the primer, wt.%:

in the composition of the insulating layer, wt.%:

in the composition of the outer layer, wt.%:

In the composition of the outer layer can optionally enter a drying accelerator di-butylurea tin grade Mettin catalyst in the amount of 0.05-0.5 wt.%.

As epoxy Dianova resin use any epoxy Dianova resin with an epoxy equivalent weight of 450÷500, for example, ED-8 GOST 10587-84, e-R THE 6-10-607-78, e-41 THE 6-10-1316-84 and other

As pigments used chromium oxide, crown zinc, strontium and lead, blue phtalocyanines, red glands of the oxide, titanium dioxide, carbon technical and other

As fillers use a micro-talc, omyacarb, mikrobasic, talc and others.

As a polyamide hardener is used, the product of the interaction of fatty acids and polyethylenepolyamine company Henkel (Germany) trademark Versamid 115.

As the iron sludge use any iron oxide, for example:

a) brand Miox firm Kärntner Montanindustrie (Austria)containing Fe₂O₃- 85-94%, Al₂About₃- 2-3%, MgO - 1-2%, Sa - 0,3-1%, SiO₂- 3-6%, Pb<0,1%;

b) iron oxide Altai Deposit Ore log" containing oxides of silicon, aluminum, magnesium and calcium, respectively, not more than 2.5, 1.8V, 0,2, 0.3% and a content of iron oxide Fe₂About₃- 90-95%;

in grade Nubifer company Nubiola (Spain)containing Fe₂About₃- 89-94%, Al₂O₃to 1.9%, MgO Of 0.1%, CaO - 0,4%, SiO₂- 4,2%, K₂O - 0,2%;

g) brand IMDOX AG firm FLOOD (Germany), containing Fe₂O₃- 92-97%, Al₂O₃of 1.6%, MgO - 1,1%, CaO - 0,8%, SiO₂at 2.3%, K₂About<0,05%, TiO₂<0,1, K₂O<0,05%, Na₂O<0,05%, P₂O₃<0,05%, MnO<0,05%.

As organically modified polysiloxane use modified polyester polydimethylsiloxane stamps BIC-307 firms BIK-Chemie (Germany) - modified polyester polysiloxane brand Baysilone OL 17 Bayer (Germany).

As institutions the institutions solvents used xylene, acetone, ethyl cellosolve, butyl acetate, ethyl acetate, etc.

As acrylic or hydroxyl-containing polyester resin is used, for example:

(a) hydroxyl-containing acrylic resin Macrynal SM 636/70 YOU company Cytec Surface Specialties, representing a polyacrylate containing hydroxyl groups;

b) hydroxyl-containing acrylic resin Macrynal SM 510 company Cytec Surface Specialties (Belgium), a polyacrylate containing hydroxyl groups;

C) hydroxyl-containing polyester resin Desmophen 670 VA, Bayer, representing a polyester containing hydroxyl groups.

As the aliphatic polyisocyanate hardener used aliphatic polyisocyanate hardeners based on the monomer of hexamethylenediisocyanate, for example, brands:

a) Desmodur N75 MPA/X Bayer, Germany;

6) Tolonate HDB75 IN the company Rhodia, France;

in) Uronal NL firm Galstaff, Italy.

As aminecontaining hardener brand Cardolite NC 562 apply aminecontaining compound on the basis of 3-n pentadecanolide company Cardanol (Netherlands) brand Cardolite NC 562.

As structuring additives used silicon dioxide grades a-175, Aerosil grades R-972, R-812 firm Degussa (Germany), Benton 38 and Bentone SD-2 by Elements (England).

As the aluminum powder used aluminum powder brands PAP-1 and PAP-2, aluminum paste brand PD, issue sceau Krasnoturyinsk plant, aluminum pasta brands Stapa 88 and Mobilux R167 company Eckart (Germany) and others.

Protecting and recovering the metal surfaces of the equipment in the conditions of abrasive wear in aggressive environments is carried out by applying to the surface of the combined coating that consists of three layers:

the first layer provides adhesion of the composition to a metal surface and corrosion protection, the coating can be a layer of corrosion thickness up to 50 microns;

- the second layer has the main shock and barrier protection;

- the third layer provides the appearance of the coating and excellent sliding abrasive materials.

Method of protecting metal surfaces is as follows.

Example No. 1: on the steel surface.

Originally applied primer composition, wt.%:

The composition for the first layer coating is prepared by mixing dissolvere part epoxy resin and organic solvents with pigments and fillers, dispersing the resulting paste on a bead mill and the preparation of the composition by adding a pigment paste the residual amount of the solvent and epoxy resin and mixing until smooth. The resulting composition is combined with hardeners and put on corroded(Permitted layer corrosion to 50 μm.) the surface with a brush or by means of air or airless spray. The primer layer is dried "up tack-free", then put the insulation layer of the following composition, wt.%:

The composition for an insulating layer is prepared as follows: a solution of epoxy resin in an organic solvent are mixed in disolver with fillers and structuring additive, then dispersed in a bead mill, then make up the composition in the mixer, equipped with a stirrer, add remaining solvent and epoxy resin and iron oxide and mix all until smooth for 40 minutes. Add hardeners. The composition is uniformly applied on the primer layer and dried "up tack-free", then put the third layer composition, wt.%:

The outer layer is prepared by mixing parts of a polyester or hydroxyl-containing acrylic resins, pigments, fillers, structuring additives, organic solvents in disolver and dispersion in a bead mill, and then in the mixer and the resulting paste is mixed with the remaining amount of resin, solvent, organically modified polysiloxane, iron oxide and aluminium powder for half an hour until smooth. Add the hardener. The composition is uniformly applied on the insulating layer. The drying time of the combined coverage of all layers up to degree 3 at 20° - 24 hours.

the safety floor is used for painting of bridges and steel structures.

Example No. 2: the iron surface.

Applied primer composition, wt.%:

Then put the insulating layer composition, wt.%:

The drying time of the combined three-layer coating to grade 3 at 20° - 24 hours.

Table 1 shows the properties of three-layer coatings.

1. The way to protect and restore corroded metallic surfaces, comprising applying a primer layer on the base composition containing epoxy Dianova resin with an epoxy equivalent weight of 450-500, polyamide hardener Versamid 115, pigments, fillers, organic solvents, followed by drying "up tack-free surface, applying an insulating layer of a composition containing epoxy Dianova resin with an epoxy equivalent weight of 450-500, polyamide hardener Versamid 115, fillers, iron oxide, organic solvents, followed by drying "up tack-free", causing the outer layer of the composition containing acrylic or polyester hydroxyl-containing resin, the curing agent is an aliphatic polyisocyanate, pigments, fillers, organically modified polysiloxane, organic solvents, followed by drying to complete curing, characterized in that the primer and the insulating layers impose additional aminecontaining compound brand Cardolite NC 562-based 3-n pentadecanolide, insulating and the outer layer impose additional structuring additive, and in the outer layer further added aluminum powder and iron oxide, the next is the rate of components in layers:

in the composition of the primer, wt.%:

in the composition of the insulating layer, wt.%:

in the composition of the outer layer, wt.%:

2. The method according to claim 1, characterized in that the composition of the outer layer optionally enter a drying accelerator dibutyltin tin, Mettin catalyst in the amount of 0.05-0.5 wt.%.