RU2290421C1 - Composition for protective cover - Google Patents

Abstract

FIELD: anticorrosive materials.

SUBSTANCE: invention relates to a method for preparing compositions designated for protecting constructions made of aluminum alloys, different steels and polymeric composition materials including carbon plastics against effect of environment (moisture, erosion, dynamic loading) at temperature exploitation from -60°C to +150°C. The composition comprises the following ratio of components, mas. p. p.: a binding agent, 100.0; a hardening agent of amine type, 15.0-50.0; a modifying agent, 3.0-50.0; a filling agent, 7.0-50.0; an organic solvent, 140.0-400.0. As a binding agent the composition comprises epoxy diane resin or a mixture of epoxy diane resins of molecular mass 1000-3500 Da. As a modifying agent the composition comprises low-molecular epoxy urethane or butadiene acrylonitrile carboxylate rubber. As a filling agent the composition comprises zinc oxide or boron oxide thread-like crystals. Additionally, the composition can comprise pigments and corrosion inhibitors. Invention provides enhancing water resistance and resistance against dynamic loading and effect of rapid air flow containing sand particles and rain drops.

EFFECT: improved and valuable technical properties of composition.

2 tbl, 9 ex

Description

The invention relates to the field of compositions based on modified epoxy oligomers designed to protect structures of aluminum alloys, various steels, as well as polymer composite materials, including carbon fiber, from environmental factors (moisture, erosion, dynamic loads) at operating temperatures from - 60 ° С to + 150 ° С.

One of the promising areas of modern materials science is the creation of highly effective protective coatings that ensure the long-term performance of structural elements under the influence of a corrosive environment, dynamic loads, high-speed air flow containing sand particles, rain drops, which during the operation of products and structural elements contribute to the destruction and delamination of coatings .

A known composition based on an organic binder, for example, epoxy or acrylic, containing a transparent mineral filler is aluminum oxide in an amount of (40-80)%, with a particle size of from 10 to 40 microns. The above composition has high hardness and wear resistance (French patent No. 2556735).

A significant disadvantage of this composition is its rigidity, the presence of high internal stresses, which when exposed to dynamic loads reduce the adhesion of the coating to the surface to be protected and contribute to the destruction of the coating.

A known composition based on polyesters and polyurethane vinyl dioxane, which has high adhesion to aluminum, polymeric materials, water resistance, resistance to shock (US patent No. 6300457).

This coating has insufficient resistance to gas-abrasive and gas-droplet erosion, low water resistance.

A known composition for a wear-resistant coating, which is a mixture of hydrolysis products and condensation products of epoxy functional silane, functional compounds of carboxylic acid, metal oxide colloid and colloidal silica (US patent No. 6324097).

This coating has high physical and mechanical properties, wear resistance, adhesion to metal surfaces. A significant disadvantage of this coating is low adhesion to carbon fiber, insufficiently high moisture resistance.

Known composition for coatings, including epoxy Dianova resin, alkyl phenolamine resin Octofor, low molecular weight butadiene acrylonitrile carboxylate rubber, polyoxypropylene oxide and filler, cured by amine hardener (RF patent No. 2059575).

This composition has a high viability during storage, high adhesion to metal surfaces, water resistance.

The specified coating has a significant drawback - low adhesion to polymer composite materials, especially carbon fiber, and, consequently, low resistance to gas-abrasive and gas-droplet erosion.

The closest analogue of the invention, adopted as a prototype, is a composition for protecting metal, concrete and wooden surfaces of the following composition, wt.%:

Epoxy Resin Diane - 12-20 Nitrile butadiene rubber - 8-14 Plasticized Terpene Resin isobornyl ether in the ratio (1: 1.6 ÷ 3.0) - 13-17 Filler - 20-37 Amine hardener - 2.4-4.0 Organic solvent - up to 100

(RF patent No. 2043379).

This coating has high physical and mechanical properties (impact strength, elasticity), adhesion to metal surfaces, corrosion resistance. However, this coating does not have a sufficiently high water resistance and low resistance to erosion and dynamic loads.

The technical task of the invention is the creation of a composition for corrosion-resistant protective coating based on modified epoxy oligomers with high water resistance and high resistance to dynamic loads and high-speed air flow containing particles of sand and a drop of rain, to protect structures made of aluminum alloys and steel, as well as coal - and fiberglass.

To solve the technical problem, a composition for a protective coating is proposed, which includes a binder - an epoxy Dianova resin, a modifier, an amine type hardener, a filler and an organic solvent, which contains an epoxy Dianova resin or a mixture of epoxy dianes with a molecular weight of 1000-3500, in as a modifier - low molecular weight epoxyurethane rubber or butadiene acrylonitrile carboxylate rubber, and as filler - whiskers of zinc oxide or nitride boron in the following ratio, mass parts .:

Specified Binder - 100.0 The specified modifier - 3.0-50.0 Amine hardener - 15.0-50.0 Zinc oxide whiskers or boron nitride - 7.0-50.0 Organic solvent - 140.0-400.0

As an amine type hardener, the composition contains a polyamide resin or an organosilicon amine.

As an organic solvent, the composition contains a mixture of xylene, acetone and butyl acetate or a mixture of acetone, xylene and ethyl cellosolve.

To impart color to the coating, pigments (titanium dioxide, chromium oxide, etc.) are introduced into the composition in an amount of 10.0-30.0 parts by weight, and corrosion inhibitors (chromium phosphate, chromate can be added to the composition to increase the protective anticorrosion properties of the coating). strontium, barium chromate, etc.) in an amount of 10.0-40.0 parts by weight

As a binder in the present invention can be used various epoxy Dianova resins with a molecular weight of 1000-3500 and a mass fraction of epoxy groups from 2.5 to 12.0% grades E-41, E-44, E-49, E-05K ( TU6-10-1316-78, TU6-10-1347-75, TU6-10-606-84, TU 301-10-1423-91) or mixtures thereof.

Used as a modifier low molecular weight epoxyurethane rubber PEF-3A with terminal epoxy groups (TU 6-10-034-66-80) or butadiene acrylonitrile carboxylate rubber with a molecular weight of from 20,000 to 30,000 (TU 6-00-05807983-160-95), due to the presence of reactive functional groups, they interact with both an epoxy binder and a hardener. As a result, a supramolecular structure is formed where elastic rubber inclusions are present in the rigid epoxy polymer matrix, which contribute to the redistribution and dissipation of mechanical stresses arising from external influences. Such a structure is characterized by a low tendency to crack formation, i.e. increased resistance to dynamic and erosive influences.

An amine-containing ethoxy derivative of silicon (organosilicon amine) -γ-aminopropyltriethoxysilane AGM-9 (TU 6-02-724-77), 1-aminohexamethylene-6-aminomethylene-triethoxysilane AGM-3 (TU 6-02- 586-86), or the condensation product of γ-aminopropyltriethoxysilane ASOT-2 (TU 6-02-1250-83). The used hardener AGM-9 interacts not only with the main film-forming, but also increases the adhesion to the surface of carbon and fiberglass.

In the proposed composition, a low molecular weight polyamide resin with a molecular weight of from 2200 to 2800, for example, grades PO-200 or PO-300 (TU6-10-1279-78, TU 6-10-1108-76) can also be used as a hardener.

The introduction of filler significantly affects the properties of cured coatings. Fine-dispersed high-modulus fillers used in the composition for protective coating - whiskers of zinc oxide (TU 6-00-5808009-235-89) or boron nitride (TU 2036-7-7-91), due to their morphological features, increase dynamic strength, redistribute mechanical stresses and counteract the destruction process under dynamic action.

The above composition has high adhesive strength to the protected surface of aluminum alloys, various steels, polymer composite materials, including carbon plastics, as well as mechanical strength, resistance to gas-abrasive and gas-droplet erosion, moisture resistance, dynamic resistance and corrosion resistance.

The composition of the protective coating used to protect metals can be used in a system with various primers containing corrosion inhibitors.

Examples of the invention are shown in table 1.

The technology for preparing the protective composition (examples 1-4) is as follows: an epoxy resin or a mixture of resins was dissolved in a mixture of solvents, for example, acetone, butyl acetate and xylene or a mixture of solvents acetone, ethyl cellosolve and xylene, a filler was introduced (whiskers of zinc oxide or boron nitride ) and dispersed in a bead mill to a milling degree of 25-30 microns. Before use, a modifier and hardener were introduced into the composition, mixed and adjusted to a working viscosity.

The compositions shown in examples 5, 6 are prepared similarly to the previous examples, but when dispersed, pigments are added to give the desired color to the coating.

The compositions shown in examples 7, 8 are prepared similarly to the previous examples, but corrosion inhibitors are introduced instead of pigments.

From the compositions shown in examples (1-8), coatings 150-170 μm thick were obtained by pneumatic spraying on samples of aluminum alloy D-1T, carbon fiber, fiberglass, and St3 steel. The curing mode of the coating is 2-3 hours at 150-170 ° C. The adhesive strength at separation, water swelling, resistance to gas-abrasive and gas-droplet erosion, impact strength, tensile elasticity, durability of coatings under cyclic tension, protective properties on aluminum alloy and steel during salt spray testing were determined.

The results are shown in table 2.

As can be seen from the above examples, the proposed composition in comparison with the prototype has increased by 50% adhesion to aluminum alloys and increased 2.5 times adhesion to carbon and fiberglass, reduced 2.5-3 times water swelling and significantly exceeds it in erosion resistance and resistance to dynamic loads.

Table 1 Name of components The composition of the examples Prototype one 2 3 four 5 6 7 8 Epoxy resin E-41 with mol. weighing 1000 - one hundred 70 one hundred one hundred - one hundred - - Epoxy resin E-49 with mol. weighing 2500 one hundred - thirty - - one hundred - one hundred - Epoxy resin ED-20 - - - - - - - - 12 Butadiene acrylonitrile carboxylate rubber SKN-26-1.25 - 17 - 3 - - twenty - - Epoxy urethane rubber PEF-ZA 12 - fifty - fifty 40 - thirty - Butadiene nitrile rubber SKN-18-1A - - - - - - - - 8 Terpene resin plasticized with isobornyl ether - - - - - - - - 13 ZnO whiskers 7 thirty fifty - 25 fifteen fifteen - - Whiskers BN - - - twenty - - - twenty - Titanium dioxide (rutile) - - - - twenty - 10 - - Chromium oxide - - - - - thirty - - fifteen Strontium chromate - - - - - - 10 thirty - Chromium phosphate - - - - - - twenty - - Aluminum powder - - - - - - - - 5 Polyethylene polyamine - - - - - - - - four γ-aminopropyltriethoxysilane AGM-9 fifteen 35 25 - - - - twenty - 1-aminohexamethylene-6-aminomethylene triethoxysilane AGM-3 - - - - - - twenty - - The condensation product of γ-aminopropyltriethoxysilane ACOT-2 - - - - fifty - - - - Low molecular weight polyamide PO-200 - - - fifty - thirty - - - Toluene - - - - - - - - 23.1 Acetone fifty 70 fifty thirty 140 fifty one hundred one hundred twenty Xylene 60 one hundred one hundred fifty 140 one hundred one hundred one hundred - Butyl acetate - 155 one hundred 60 120 - - fifty - Ethyl cellosolve 60 - - - - fifty fifty - -

table 2 Comparative properties of coatings Property metrics The proposed composition of the examples Prototype one 2 3 four 5 6 7 8 Coating thickness, microns 150 160 150 150 160 170 160 150 180 Adhesion strength (σ _adg ), MPa, a) to aluminum alloy 68.6 71.6 65.5 66.1 59.5 61,4 59.8 61.3 43.56 b) to carbon fiber 53.5 55.1 56.6 54.9 55.1 56.8 - - 20.8 c) to fiberglass 59.9 66.3 66.5 59,4 58.7 62.1 - - 22.1 Water swelling after 100 h of testing at a temperature of 20 ° C,% a) on carbon fiber 2.1 1.95 1.99 2.6 1.88 2.1 2.2 2.15 6.3 b) on aluminum alloy 1.95 1.89 1.86 2.01 1.75 1.97 2.12 2.07 4.8 The intensity of gas-droplet erosion, nm / g at a temperature of 20 ° C 26.5 18.3 22.3 25,4 22.3 29.6 28.3 31.5 350,3 The rate of erosion during drop impact, at an angle of impact of 30 degrees, microns / s 0.24 0.18 0.22 0.21 0.25 0.23 0.29 0.31 10.1 Durability of the coating under cyclic tension, cycles 2930 2110 2600 2940 2850 2940 2450 2440 thirty Initial impact resistance, J fifty fifty fifty fifty fifty fifty fifty fifty fifty Impact resistance after artificial aging at temperatures (-60 ... + 150) ° С for 10 cycles fifty fifty fifty fifty fifty fifty fifty fifty thirty

Continuation of table 2 Property metrics The proposed composition of the examples Prototype one 2 3 four 5 6 7 8 The elasticity of the coating in tension in the initial state 5,6 5.7 5.5 5.7 5,6 5,4 5,4 5.3 4,5 The elasticity of the coating under tension after artificial aging at temperatures (-60 ... + 150) ° C for 10 cycles 4.4 4,5 4.4 4.7 4.3 4.2 4.3 4,5 2,5 Corrosion resistance of coatings after testing in a salt spray chamber for 6 months - on an aluminum alloy D-1 T no corrosion no corrosion no corrosion no corrosion no corrosion no corrosion no corrosion no corrosion Small rash over the entire surface - on steel St3 no corrosion no corrosion no corrosion no corrosion no corrosion no corrosion no corrosion no corrosion Small rash over the entire surface, 3 corrosion points

Claims (5)

1. The composition for a protective coating, comprising a binder - an epoxy Dianova resin, a modifier, an amine type hardener, a filler and an organic solvent, characterized in that it contains an epoxy Dianova resin or a mixture of epoxy Dianova resins with a molecular weight of 1000-3500, and as a modifier, low molecular weight epoxyurethane or butadiene acrylonitrile carboxylate rubber, and as filler, whiskers of zinc oxide or boron nitride in the following ratio of components in, parts by weight .: Specified Binder 100.0 The specified modifier 3.0-50 Amine hardener 15.0-50.0 Zinc oxide whiskers or boron nitride 7.0-50.0 Organic solvent 140.0-400.0 2. The composition according to claim 1, characterized in that as the hardener of the amine type it contains a polyamide resin or organosilicon amine. 3. The composition according to claim 1, characterized in that as an organic solvent it contains a mixture of xylene, acetone and butyl acetate or a mixture of acetone, xylene and ethyl cellosolve. 4. The composition according to claim 1, characterized in that it further comprises pigments in an amount of 10-30 wt.h. 5. The composition according to claim 1, characterized in that it further comprises corrosion inhibitors in an amount of 10-40 wt.h.