RU2283331C1 - Composition for anticorrosion coating - Google Patents

Abstract

FIELD: composition for corrosion protection of basic constructional materials (steel, concrete).

SUBSTANCE: claimed composition contains (mass %): polymeric film-forming substance 40-52; natural fine-grain iron alpha-oxide 11-27; organosilicon curing agent 1`2-17; thiocol 7-10; synthetic silica 3-5; strontium chromate 7-9. Solution of epoxy resin in xylene and acetone is used as polymeric film-forming substance. Natural fine-grain iron alpha-oxide contains (mass %): silica, aluminum oxide, magnesium oxide, and calcium oxide not more than 2.5; 1.8, 0.2, and 0.3, respectively and Fe₂O₃ 85-95 %. As organosilicon curing agent organosilicon amine derivatives are used.

EFFECT: coating of increased fuel resistant and durability in high aggressive medium, containing, in particular, fuel with water impurity.

2 tbl, 6 ex

Description

The invention relates to the field of corrosion protection of basic structural materials / steel, concrete / and can be used to protect against corrosion of the internal and external surfaces of fuel tanks and pipelines operating in a fuel medium mixed with water.

Known composition for anti-corrosion coating, including epoxy resin, solvent and pigments, which are used as aluminum or zinc powder / Protasov V.N. The effectiveness of the use of anticorrosive coatings for oilfield equipment. M .: VNIIOENG. - 1984, - p. 44-45 /.

The increase in the corrosion resistance of coatings based on such compositions in comparison with pure paints and varnishes is due to the increased resistance of the composition to the combined effects of various corrosion factors / oxidation, photolysis, electrochemical processes, alternating and dynamic loads of products /. Protective protective effect / zinc, aluminum / pigments reduces the corrosion rate even in highly aggressive environments.

However, the resistance of coatings from such compositions to certain types of corrosion / abrasion, pitting, cavitation / is limited. Another disadvantage is the gas evolution during the reaction with aggressive acidic and alkaline media, loosening the coating structure and sharply worsening its protective properties.

Also known is a composition for an anticorrosive coating, including a polymer film-forming substance, which is used as an epoxy resin, and an organosilicon hardener / Chode L.G. and others. Epoxy silicon-organic enamels with high weather resistance. Paintwork materials and their application. - 1995. - No. 3-4, - p. 33-34 /.

This composition compared with the above has a higher strength and adhesion to metal. However, the durability of the coating under the complex effects of corrosion factors is small / 7-8 years /.

The closest to the invention in technical essence is a composition for anticorrosion coating, including a polymer film-forming substance, which is used as a solution of epoxy resin E-41 in xylene and acetone, thiokol, a type of natural fine-grained alpha-iron oxide - speculates Altai deposit "Rudny Log" with the content of oxides of silicon, aluminum, magnesium and calcium, respectively, no more than 2.5; 1.8; 0.2 and 0.3% and a high content of alpha-iron oxide - Fe ₂ About ₃ 90-95% and 12-16% organosilicon hardener ASOT-2 / patent RU 2174136, C 09 D 5/08, 2001 - prototype / .

The disadvantage of this composition is that it does not provide the required durability of corrosion protection of fuel tanks operating in a fuel medium with impurities of water. In addition, it provides only a multilayer coating. This leads to a significant increase in the time of coating, as well as to an increase in the loss of composition, especially when applying an anti-corrosion coating on the inner surface of pipelines and tanks.

The objective of the invention is to increase the fuel resistance and durability of the coating protection in highly aggressive operating conditions.

The technical result is an increase in fuel resistance and durability of the coating in highly aggressive operating conditions.

The technical result is achieved by the fact that the known composition for anticorrosion coating, including a polymer film-forming substance, which is used as a solution of epoxy resin E-41 in xylene and acetone, thiokol, a type of natural fine-grained alpha-iron oxide - speculates Altai deposit "Rudny Log" with the content of oxides of silicon, aluminum, magnesium and calcium, respectively, no more than 2.5; 1.8; 0.2 and 0.3% and a high content of alpha-iron oxide - Fe ₂ About ₃ and the derivative of organosilicon amines ASOT-2 as an organosilicon hardener, contains specularity with the content of alpha-iron oxide in it 85-95%, and additionally the composition contains synthetic silica - Aerosil A-175 and strontium chromate, in the following ratio, wt.%:

solution of epoxy resin E-41 in xylene and acetone 40-52 the above kind of natural finely scaled alpha iron oxide 11-27 the above silicone hardener ASOT-2 12-17 thiocol 7-10 synthetic silica - aerosil A-175 3-5 strontium chromate 7-9

The essence of the invention lies in the fact that the addition of additional strontium chromate and Aerosil A-175 to the composition in a given percentage increases fuel resistance and improves the corrosion resistance of the coating in highly aggressive environments and provides corrosion protection of the equipment in one layer.

To prepare the anticorrosive composition, a solution of epoxy resin E-41 / TU 6-10-507-76 / and silicone hardener ASOT-2 / TU 6-02-1250-83 / are used. E-41 - a solution in xylene and acetone. Hardener ASOT-2 is a derivative of organosilicon amines / 50% solution in cyclohexanone /.

As a speculary, a variety of natural small-scaled alpha-iron oxide of the Altai deposit "Rudny Log" is used with a low content of silicon, aluminum, magnesium and calcium oxides and a high content of iron oxide. The chemical composition of this specularite is characterized by the following data: the content of oxides of silicon, aluminum, magnesium and calcium, respectively, no more than 2.5; 1.8; 0.2 and 0.3% and the content of iron oxide Fe ₂ About ₃ - 85-95%. The degree of grinding of specularite is 63 microns / residue on a sieve with a hole size of 63 microns less than 2.0 wt.% /.

Liquid thiocols, for example, brand 1 thiocol, which is a polysulfide polymer with a viscosity at 25 ° C of 20.0 Pa · s, a mass fraction of SH-groups of 2.6%, viability 54 / GOST 12812-80 /, are used as a thiokol. Thiocols are used to increase the elasticity of the coating.

Strontium chromate / TU 48-4-239-82 / is a lemon yellow pigment, the mass fraction of strontium chromate is not less than 97%, the mass fraction of the residue after wet sieving on a sieve with mesh No. 0045 is not more than 43%. The advantage is low reactivity and the absence of crystalline water.

Used synthetic silica - Aerosil A-175 / GOST 14922-77 / is a powder with a high specific surface / 175 ± 20 m ² / g /, has thixotropic properties. It is characterized by an extremely high degree of dispersion, particle size from 0.15 to 0.02 microns. When dispersed in a medium wetting only part of their surface, they form bulk coagulation networks. Such nets include pigment particles and prevent their deposition, increase the viscosity of the dispersed medium. Mass fraction of the basic substance SiO ₂ 99.8%. Mass fraction of moisture no more than 2%.

The composition is prepared by mixing on a mechanical stirrer in the calculated amounts of a solution of epoxy resin E-41, specularite, thiol, aerosil and strontium chromate for 10-15 minutes at room temperature. The organosilicon hardener ASOT-2 is then added and the composition is further mixed for 10-15 minutes.

The composition is applied to the surface of the product after its preparation by the method of pneumatic spraying with a wide-nozzle spray gun or brush in the form of a single layer with a thickness of 200-300 microns.

The invention is illustrated by the following examples: coating compositions are given in table 1, the main characteristics of the coating in table 2.

From table 2 it follows that the compositions according to examples 2-4 create a single-layer coating with high fuel resistance in a mixture of fuel with water and increased durability / up to 15-20 years /.

These results are due to the introduction into the composition of an additional synthetic silica - Aerosil A-175 and strontium chromate and the choice of the appropriate content of the components. The addition of strontium chromate and Aerosil A-175 to the known composition in the proposed proportions leads, in addition to reducing the number of layers, to an increase in the content of non-volatiles / up to 64% / and, accordingly, to a decrease in the porosity of the coating, which leads to an increase in the durability of a single-layer coating when used in highly aggressive environments. Aerosil A-175 prevents the deposition of specular particles.

The nominal viscosity of the composition / without hardener / was determined using a B3-246 viscometer with a nozzle diameter of 4 mm at a temperature of 20 ± 5 ° C in accordance with GOST 8420. The water and heat resistance of the coatings was determined in accordance with GOST 21513. The mass fraction of non-volatile substances was determined in accordance with GOST 17537. Film strength upon impact, it is determined using the U-1A instrument according to GOST 4765. The film elasticity during bending is determined according to GOST 6806. The film adhesion is determined according to GOST 15140. The durability of the coating based on the proposed compositions is confirmed by the operation of fuel and oil tanks under conditions of corrosion ressivnyh media / medium fuel in admixture with water /.

Thus, the introduction of an additional two components into the anticorrosive composition: Aerosil A-175 and strontium chromate and their selected percentage increase the fuel resistance of the coating under highly aggressive operating conditions and increase the efficiency of the composition.

Table 1
Coating Compositions Components The content of components, wt.% Prototype Examples one 2 3 four 5 Solution of epoxy resin E-41 in acetone and xylene 52 52 45 40 36 47 Organosilicon hardener ASOT-2 eighteen 17 fourteen 12 10 fourteen A Variety of Natural Fine-Scaled Alpha Iron Oxide 10 eleven twenty 27 thirty thirty Synthetic silica aerosil A-175 2 3 four 5 8 - Strontium chromate 6 7 8 9 10 - Thiokol brand 1 12 10 9 7 6 9

table 2
Main characteristics of the composition and coating Indicators Examples Prototype one 2 3 four 5 Conventional viscosity of the composition / without hardener /, s thirty 40 fifty 60 75 twenty The strength of the film upon impact, J 5 5 5 5 3 5 The elasticity of the film in bending, mm 6 5 5 5 10 5 Fuel resistance / swelling in fuel for 30 days /,% 1,0 0.5 0.5 0.5 1,0 1,0 Adhesion / after holding for 1000 h in water /, score at 20 ° C one one one one 2 one at 60 ° C one one one one 2 one Number of layers one one one one - 2-3 Coating thickness, microns one hundred 200 250 300 350 150-200 The durability of the coating, years 8-10 15-20 - 8-10

Claims (1)

Composition for anticorrosion coating, including a polymer film-forming substance, which is used as a solution of epoxy resin E-41 in xylene and acetone, thiokol, a type of natural fine-grained alpha-iron oxide - speculates Altai deposit "Rudny Log" with the content of oxides of silicon, aluminum, magnesium and calcium, respectively, no more than 2.5; 1.8; 0.2 and 0.3% and a high content of alpha-iron oxide - Fe ₂ About ₃ , a derivative of organosilicon amines ASOT-2 as an organosilicon hardener, characterized in that it contains specular with an alpha-iron oxide content of 85-95 %, and additionally the composition contains synthetic silica - Aerosil A-175 and strontium chromic acid, in the following ratio of components, wt.%: Solution of epoxy resin E-41 in xylene and acetone 40-52 The above kind of natural finely scaled alpha iron oxide 11-27 The above organosilicon hardener ASOT-2 12-17 Thiokol 7-10 Synthetic silica - Aerosil A-175 3-5 Strontium chromate 7-9