Anticorrosion composition for coating metal

FIELD: chemistry.

SUBSTANCE: invention pertains to compositions based on soluble fluoropolymers, meant for protecting metallic surfaces from action of water and aggressive media. The compositions can be used in the chemical industry and other industries when making equipment. Description is given of the anticorrosive composition is given. It consists of a soluble copolymer of tetrafluoroethylene with vinylidene fluoride, organic solvents - acetone, ethylacetate, cyclohexanone and amyl acetate, low molecular epoxide diane resin of the "ЭД-8" or "ЭД-10" type, amine hardening agent product of condensation of formaldehyde and phenol with ethylenediamine of the "АФ-2" type, diluting agent - ethyl cellosolve and an extra filler - graphite or molybdenum sulphide with proposed ratios of the components. Description of the method of coating metals is also given, in which the above mentioned composition is deposited on a non-greasy surface. The first and subsequent layers are dried under the same conditions at temperature of 15-25°C for a period of 20-30 minutes, and final coating is done at 120-200°C for 4-6 hours.

EFFECT: protection of metal surfaces from water and aggressive media.

3 cl, 5 ex, 2 tbl

The invention relates to organic chemistry, in particular to compositions based on soluble farolatino designed for surface protection of metals from water and corrosive environments, they can be used in chemical, engineering and other industries in the production equipment.

It is widely known variety of protective coatings based on farolatino designed for surface protection of metals against corrosion and weathering.

Known compositions for obtaining the fluoropolymer coating on the metal containing as the basis aqueous dispersion of polytetrafluoroethylene. The known methods of forming coatings include preparation of original compositions, their consistent application to the metal in two or more layers, the intermediate drying of each layer at an elevated temperature and a final heat treatment of the coating at a temperature 260-425°required for formation of the film (RU 940495, CL 08L 27/18, publ. 20.12.1995,; EN 2034857, CL 08L 27/18, publ. 10.05.1995,; EN 2039069, CL 09D 5/08, 127/18, 08J 5/16, publ. 09.07.1995,; EN 2034875, CL 08L 27/18, publ. 10.05.1995,; EN 2174137, CL 09D 127/18, publ. 27.09.2001 year). The disadvantages of the known compositions and obtained from them coatings on metal are: weak adhesion to the substrate, the need to use a special primer is Loya, the duration and intensity of the formation of the coating.

Known fluoropolymer varnishes and primers and enamels based on them, containing soluble copolymers of triptoreline with alkylvinyl and hydroxyethylmonium esters in organic solvent - xylene (Lac DPF)used for protection of metal exposed to atmospheric influences in the construction, automobile, shipbuilding, building and chemical industry (EN 2066328, CL 08F 214/24, publ. 1996; EN 2088600, CL 08F 214/24, publ. 1997; EN 2208018, CL 08F 214/24, 127/12, publ. 2003; EN 2209215, CL 08F 214/24, 127/12, publ. 2003). The disadvantage of known varnishes - use as an organic solvent for forsuperior xylene (MPC 50 mg/m³), which is a cause of concern for those working with lacquers staff and reduces its consumer properties (Karyakin M.I., Poptsov VE Technology polymer coating. M.: Chemistry, 1983, p.15). In addition, poor adhesion to metals is not possible to obtain coatings with high performance.

Known compositions based on fluoropolymer varnishes containing copolymer of triptoreline with vinylidenefluoride (f-32L), dissolved in a mixture of esters or ketones with aromatic hydrocarbons, which are coatings for metal, characterized by low vlagopronitsaemostyu the Yu, high water and weather resistance; heat and frost resistance (EN 2217455, CL 09D 5/08, 127/24, publ. 27.11.2003 g) Lack of compositions containing the copolymer f-32L - use in the composition of the organic solvent toluene (MPC 50 mg/m³)that represents a danger to working with lacquers staff and reduces its consumer properties. Also known as Lac FL also has insufficient adhesion to the substrate, which does not allow to obtain a coating with the desired performance characteristics.

Known compositions for coatings "cold drying" on the basis of TFE with WDF (f-42L), which is a solution of f-42L in acetone (AC), butyl acetate (BAM), or a mixture thereof in the following ratio, wt.%: F-42L - 10-30 wt.%; the mixture of solvents is 70-90 wt.% (see Morozov NI and other Phase composition and mechanical properties of compositions based on solid solutions of a copolymer of tetrafluoroethylene with vinylidenefluoride, Colloid journal, 1988, vol 50, issue 4, s-702). Due to the formation of the lacquer ordered structure of the coating on the metal of this composition have good mechanical properties, increasing their durability. The main not prosperity known fluoropolymer coatings and compositions is a weak adhesion to the substrate (Chemical encyclopedia. M: Soviet encyclopedia, 1983, s.; E is Cyclopedia polymers. M: Soviet encyclopedia, 1972, Vol.3, s).

Known methods of increasing the adhesion strength and increase the durability of coatings on the basis of soluble fluoropolymers f-42L and f-32L by modification builders, which have a higher surface energy and contain the set of active groups capable of chemically interacting with the surface of the substrate (Floranova coverage. The basic properties and methods of modification, "Paints and varnishes 2002/2003 Annual professional Handbook, Supplement to the weekly "Support", M, p.64). To improve the adhesion of coatings from solutions of ftoropolymer f-42L and f-32L suggested modifiers polyfunctional silanes, whose molecules are present ethoxyline and amino type AGM-9, AGM-3 ASOT-2.

Before coating the metal surface was degreased with toluene and treated with 3%solution of the modifier in the organic solvent by dipping method. The coating was applied by means of air spraying. Although there was an increase coating adhesion to 3000-4000 N/m instead of 10-15 N/m, due to the inaccessibility of the modifier method has not found wide application in industry.

The closest in composition to the present invention is known fluoropolymer-epoxy composition for anticorr the precise coating of metal surfaces, obtained by blending in the environment of organic solvent f-42L and low-molecular epoxy Dianova resin with the addition of the modifier and curing agent (SU 1616937, CL 09D 127/08, 7/14, 5/08, publ. 1990). Getting famous songs includes several operations.

The solution of the foaming agent get in the tank with a mechanical mixer or ball mill. In the capacity enter the estimated amount of the copolymer f-42L, add a mixture of solvents with precipitator (40 wt.% ethyl acetate and 10 wt.% acetone, 50 wt.% butyl acetate), stirred until dissolved, add low molecular weight epoxy resin grade ED-20 and again stirred for 5-6 hours

- Modified filler getting in the adsorption column transmission within 1-1 .5 hours with a feed rate of 5 ml/min 5-10%solution of 1,2,3-benzotriazole in ethanol through pre-calcined barium sulfate.

Separately preparing a pigmentary paste, mixing previously prepared modified filler and solution of the foaming agent (30-40 wt.% of the total number). "Pasta" is produced by milling the mixture in a ball mill to a fineness of 40-50 microns.

A well-known composition is produced by adding the received "pigment paste" in the remainder of the solution of the foaming agent and the final dispersion of the mixture p and stirring for 22-24 hours

In the end you get a known anti-corrosion composition for coating comprising a water soluble copolymer f-42L, a mixture of organic solvents, low-molecular Dianova epoxy resin ED-20 with the addition of amine hardener THETA and modifier on the basis of barium sulfite in the following ratio, wt.%:

Before application to the substrate in the composition is injected hardener - tetramethylchroman (THETA) in an amount of 0.6 wt.%.

From the resulting compositions have coatings on metal with good adhesion and high corrosion resistance. Conditions for obtaining coatings of these compositions on metal in the patent are not given.

The lack of known composition is the use of modifier - of barium sulphate, which complicates and delays the receipt of the offer of composition by two special operations: direct its preparation, which of the processing of barium sulphate 2%solution of 1,2,3-benzotriazole, and then getting out of it "pigment paste" and its homogenization and dispersion using a ball mill. As a result, the method of preparation of this composition inefficient, because the duration of its preparation is more than 36 hours in Addition, the mixture requires special additional equipment, in particular a ball mill for dispersion of the modifier in the preparation of "pigment paste".

Another drawback is the use in the composition of low molecular weight epoxy Dianova resin brand ED-20 (molecular weight 300-430), which is a viscous liquid, reduces the efficiency of the method, because when you work with it the inevitable losses (on the walls of the container after draining).

The technical result, which provides the present invention is to obtain an anticorrosive composition based on soluble forsuperior tetrafluoroethylene with vinylidenefluoride, suitable for the production of coatings on the metal, reducing the time and simplifying the process of its preparation, reducing the intensity of formation of coatings while maintaining their performance.

This technical result is achieved by the fact that the anti-corrosion composition comprising soluble is copolymer tetrafluoroethylene with vinylidenefluoride, organic solvents - acetone, ethyl acetate, low molecular weight epoxy Dianova resin and amine curing agent additionally contains as the organic solvent of cyclohexanone and amylacetate, thinner - ethyl cellosolve as epoxy - Dianov resin grade ED-8 or ED-10, as the amine curing agent is a condensation product of formaldehyde and phenol with Ethylenediamine brand AF-2 in the following ratio, wt.%:

The composition further comprises a filler is graphite or molybdenum disulfide in an amount of 5-20 wt.%.

The coating on the metal surface is obtained by applying anti-corrosion composition on fat surface, and the first and all subsequent layers are dried in the same the x conditions at a temperature of 15-25° C for 20-30 min, and the final formation of the coating is carried out at a temperature of 120-200°C for 4-6 hours

The method was verified in the laboratory.

Example. For the preparation of compositions in a container equipped with a stirrer, was placed a copolymer of tetrafluoroethylene with vinylidenefluoride (preferably brand f-42L), type epoxy resin grade ED-8 or ED-10, acetone and mix them with 40-50°after that, the mixture was added the appropriate listed solvents: ethyl acetate, amylacetate and cyclohexanone. All the components of the mixture in the inventive within successively, with stirring each time 15-30 min until complete dissolution of the polymers. At the end add the diluent - ethyl cellosolve, the filler is graphite or molybdenum disulfide, and again mix. The maximum cooking time of the composition is not more than 3 hours

Before application to the substrate in the resulting composition is injected hardener - AF-2. After adding the hardener composition suitable for use within 3 hours

The proposed antirust compositions shown in table 1 (examples 1-4).

In the presented compositions prepared coating.

The coating on the metal surface to receive irrigation anticorrosive composition on fat in 10%solution of a hydroxide NAT the Oia aluminum foil 100× 100 mm, the First layer is dried at a temperature of 15-25°C for 20-30 minutes, All subsequent layers formed under the same conditions. After application of the required number of layers to a thickness of 50-100 μm, the coating is dried at a temperature of 120-200°C for 4-6 hours

Properties of the obtained coatings determined by standard methods:

the thickness of the single-layer coating on a metal plate is measured with a micrometer;

- the drying time of the coating according to GOST 19007-73;

- adhesion - method cross-hatch test after boiling in water for 30 min according to GOST 15140-78;

- wetting angle is determined according to the method of sitting drops using cathetometer with measuring angular nozzle.

Properties of the coatings obtained on the metal surface, are shown in table 2 (examples 1-4).

Simultaneously composition is prepared in accordance with the prototype and form from it the coating on the metal (example 5).

From the presented data shows that the proposed anti-corrosion composition based soluble forsuperior tetrafluoroethylene with vinylidenefluoride suitable for coatings on metal.

The proposed composition and ratio of the components: forsuperior and epoxy resin, dissolved in a mixture of organic solvents, filler and hardener, and the sequence of their mixing allows, unlike Izv the STN method, significantly (almost in order) to reduce the cooking time of the composition and to simplify and cheapen the process.

The exception of the use of modifier allows you to significantly speed up and simplify the receipt of offer of composition by eliminating two special operations: direct preparation processing of barium sulfite, and the subsequent reception of "pigment paste" and its homogenization and dispersion using a ball mill. For the preparation of the proposed anti-corrosion composition sufficient unit with mixer.

Replacement of low-molecular epoxy resin ed-20 (molecular weight 300-430) resin ed-8 (molecular weight 660-860) or ed-10 (molecular weight 860-1100) eliminates the need to use in the composition of the modifier.

The use of bulk solid resin ED-8 ed-10 is more convenient and economical, since the resin ED-20, used in a certain way - viscous liquid, which is inevitable losses (on the walls of the container after draining).

The use of hardener AF-2 with mixed functions allows you to accelerate the formation and drying of the proposed composition and significantly increase its strength (table 2, examples 1-4), compared with the prototype (example 5).

Add in the proposed composition of the filler (graphite or molybdenum sulfide) can significantly improve the strength of the coating (table 2, examples 3 and 4), including in comparison with the prototype (table 2, example 5).

The obtained composition based soluble farolatino designed for surface protection of metals from water and corrosive environments, can be used in chemical, engineering and other industries in the production equipment.

1. Anti-corrosion composition comprising a water soluble copolymer those who of retoration with vinylidenefluoride, organic solvents - acetone, ethyl acetate, low molecular weight epoxy Dianova resin and amine curing agent, characterized in that it further contains as an organic solvent of cyclohexanone and amylacetate, thinner - ethyl cellosolve as epoxy - Dianov resin grade ED-8 or ED-10, as the amine curing agent is a condensation product of formaldehyde and phenol with Ethylenediamine brand AF-2 in the following ratio, wt.%:

2. The composition according to claim 1, characterized in that it further contains a filler is graphite or molybdenum disulfide in an amount of 5-20 wt.%.

3. A method of producing coatings on metal, wherein the anticorrosive composition obtained according to claim 1, nanosat fat surface, the first and all subsequent layers are dried under the same conditions at a temperature of 15-25°C for 20-30 min, and the final formation of the coating is carried out at a temperature of 120-200°C for 4-6 hours