RU2304600C2 - Application of the composition filled with the hollow microspheres and used as the anticorrosive and heat-insulating coating of the pipelines - Google Patents

Abstract

FIELD: petroleum industry; natural gas industry; chemical industry; other industries; production of the compositions used for application of the anticorrosive and heat-insulating coatings on the pipelines.

SUBSTANCE: the invention is pertaining to the field of production of the coatings possessing the anticorrosive and heat-insulating properties at their deposition on the pipeline. The invention is dealt with application of the water-suspension composition including as the binding the water-emulsion polymeric latex composition containing the latex on the basis of the copolymer selected from the group of the (homo) acrylate copolymer, styrene-acrylate copolymer, or styrene-butadiene copolymer, polybutadiene polymer, polyvinylchloride polymer, polyurethane polymer, the polymer or the copolymer on the basis of the vinyl acetate or their mixtures, in the combination with the surface-active substance and the water, and as the filler it contains the mixture of the hollow microspheres ( made out of glass, ceramic, ash, polymers) differed among themselves by the dimensions within the limits of 10-500 microns and the bulk specific gravity within the limits of 650-50 kg/m³ and taken in the certain ratios. As a result of application of this composition as the coating the invention ensures the simultaneous protection of the surfaces against corrosion and the heat insulation and offers the possibility to exercise protection of the substances and the products operating under conditions of the heightened humidity, under the conditions of action of the heightened temperatures, under the conditions of action of the temperatures difference, that is specially important at protection of the metallic pipelines, both the pipelines of the hot-water supply and the natural gas pipelines and petroleum pipelines.

EFFECT: the invention ensures the simultaneous heat insulation and protection of the surfaces against corrosion, the possibility to exercise protection of the substances and the products operating under conditions of the heightened humidity, action of the heightened temperatures and the temperatures difference, that is specially important at protection of the metallic pipelines of the hot-water supply, the natural gas and petroleum pipelines.

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Description

The invention relates to the chemical industry relates to the creation of tools used in anticorrosion protection and thermal protection of various surfaces from overheating, in particular metal surfaces, concrete surfaces, plastered surfaces and other building structures made of metal and concrete, operated in an atmosphere of aggressive environments, in particular for thermal insulation and corrosion protection of pipelines, including thermal insulation of heat and water supply pipelines, as well as gas and oil pipelines, for heat Zolation and corrosion protection, for example, roofs, walls of houses and other elements in house building, especially those operating under specific and quite severe conditions, in particular in permafrost areas, under water and at large changes in temperature and pressure, as well as when exposed to high temperatures, exposure to superheated steam.

The invention can be used in housing and communal services, the construction of various structures, oil, gas and petrochemical industries.

It is known to use various polymer tapes of polyethylene, polyvinyl chloride 200-500 microns thick for insulation, for example, pipelines. These homogeneous non-porous materials are a diffusion barrier preventing the penetration of a corrosive medium to the metal surface of pipelines. (Overview "Polymer coatings for pipeline insulation" M., 1988, issue 1 (75), pp. 19-25). However, such insulation does not provide the necessary thermal insulation of pipelines due to the specifics of these materials used.

It is known to use various bitumen insulating mastics for pipe insulation. The mastics used contain a number of fillers with specific properties that affect the physicomechanical and protective properties of the resulting coatings, such as rubber crumb, fiberglass. Mastics are applied in a molten state. However, they are characterized by a rather complicated manufacturing technology and, despite good adhesive properties and other mechanical properties, also do not provide the necessary thermal insulation of pipelines, especially oil and gas pipelines. (ibid. Overview. Polymer coatings for pipeline insulation. S.34-42).

It is known to use compositions based on liquid glass with various fillers - expanded vermiculite, dolomite (RU 2126776, 27 / 02.1999) or hollow ash microspheres - ablation of thermal power plants (SU 1724524, 04/07/1992, GB 1550184, 1979) or a mixture of glass microspheres with microspheres in in the form of flue waste from burning coal with a particle size of 10-300 microns (RU 2098379, 12/10/1997).

However, all of these known compositions are intended to produce heat-insulating materials, structures, and not coatings, for example in the form of heat-insulating plates, which limits their use.

It is known to use a thermo-hydroinsulating substance for coating a pipeline, which is a composition containing an epoxy resin, a hardener for it, a plasticizer and glass microspheres with a diameter of 200-300 microns. (application RU 93052300). The known composition provides good physicomechanical and heat-insulating properties to coatings, however it refers to sufficiently toxic substances, is inconvenient to use and does not provide the necessary level of heat-insulating properties when protecting pipelines.

It is known to use an anti-corrosion coating for a pipeline containing an epoxy coating based on bisphenol A bonded to the pipe and an extruded thermoplastic tape covering the epoxy coating and fixed to it with glue; the epoxy coating has a thickness of 0.05-0.25 mm, and the anticorrosion coating itself has a thickness of 0.15-1.27 mm (SU 1165242, 06/30/1985).

However, this known coating is technologically difficult to perform and is not capable of simultaneously performing the function of a heat-insulating coating.

It is widely known that various foams are used as thermal insulation materials and coatings. Thus, in particular, a composition for producing heat-insulating foam is known, including hollow microspheres isolated from fly ash, fly ash microspheres) and oxides, borate or zinc carbonate, and silica powder as reinforcing agents (application) as a binder, liquid glass, as a refractory filler GB 1550184, 1979).

Currently, water-based coating materials, which are the most environmentally friendly materials, are widely used.

So, for example, it is known to use the composition to obtain a protective coating for building structures, for example from concrete, including in parts by weight sodium liquid glass with a module of 2.8-100, lead lithium 0.5-1.5, finely ground perlite 80-100 and oligomethylhydridesiloxane GKZH-94-2-3 (SU 1773923, 11/07/1992). However, this composition does not provide simultaneous thermal protection of the protected surfaces.

It is known to use compositions containing various polymer latexes as a binder, in particular for protecting the surface of metal pipelines against corrosion, for example, a composition comprising styrene butadiene latex, sodium liquid glass, alite cement, quartz sand, latex stabilizer, trisodium phosphate, fiberglass and water ( RU 1717580, 03/07/1992). However, this composition also does not provide the necessary complex of thermal insulation properties of the resulting coating.

The technical task of the claimed invention is to increase the insulating properties of coatings of various surfaces operating in specific harsh conditions, while protecting them from corrosion, improving environmental properties and simplifying the technology for producing coatings.

The task is achieved by using as an insulating and anti-corrosion coating an inlet-suspension composition with a viscosity of 1 to 100 Pa · s, containing as a polymer binder a water-based polymer latex composition comprising from 10 to 90% vol (co) polymer selected from the group: acrylate homopolymer, styrene-acrylate copolymer, styrene-butadiene copolymer, polystyrene, butadiene polymer, polyvinyl chloride polymer, polyurethane polymer, vinyl acetate polymer or copolymer or mixtures thereof, and from 10 to 90% vol. mixtures of water and a surfactant, and the water-suspension composition contains as a filler a mixture of hollow microspheres, differing in size from 10 to 500 micrometers and bulk density in the range from 650 to 50 kg / m ³ and selected from the group, including hollow glass microspheres, hollow ceramic microspheres, hollow polymer microspheres, hollow man-made (ash) microspheres or mixtures thereof in the following ratio of components of the inlet-suspension composition, vol. %:

the above polymer latex composition 5-95 the above hollow microspheres 5-95

Moreover, the aqueous emulsion latex composition may additionally contain various auxiliary (target) additives, such as white and colored pigments, such as, for example, titanium dioxide, zinc oxide, iron oxide pigments, chromium oxide pigments and other coloring pigments; flame retardants, corrosion inhibitors, rust converters to enhance technological and protective properties, depending on the operating conditions of the protected surfaces and the type of surface.

The following are specific types of different targeted supplements from among those indicated.

The viscosity of the water-suspension composition is determined by the method of applying the composition and is in the range from 1 to 100 Pa · s.

iron oxide pigments, chromium oxide pigments, phthalocyanine blue, etc .;

flame retardant (flame retardant) additives, such as, for example, aluminum trihydrate, ammonium polyphosphate, zinc borate, mica, asbestos, etc .;

rust converters, such as, for example, a PRL-2 converter based on phosphoric acid, No. 444 based on phosphoric acid, etc .;

corrosion inhibitors, such as, for example, sodium nitrite, sodium benzoate, guanidine chromate, zinc tetraoxychromat, AKOR-1, NG-203 in amounts traditionally used in such similar aqueous dispersions.

As a polymer binder, the composition used to obtain the anti-corrosion and heat-insulating coating according to the invention contains known latexes based on (co) polymers of acrylate, styrene, vinyl acetate, styrene-butadiene copolymer, polyurethane, polyvinyl chloride (polyvinyl chloride polymer) containing water and surfactants , for example, the type of ethoxylated alkyl phenols, such as OP-6, OP-7, OP-10, praxanol based on block copolymers of ethylene oxide and propylene, and others traditionally used in one dispersive systems; as well as various other target additives, such as white and coloring pigments, corrosion inhibitors, rust converters, flame retardants, etc., also prepared directly based on the latexes of the above or their polymer blends with a polymer content of 5 to 95 vol. %

So, for example, when obtaining the anticorrosion and thermal insulation coating according to the invention as a polymer binder, the composition contains such latex polymer systems as latex based on copolymers of vinyl acetate with ethylene, methyl methacrylate and methacrylic acid (the basis of paints E-BC-511, E-BC-17), based on a polyvinyl acetate dispersion (50%) in the form of paints E-VA-27, E-VA-0112 and others; latex systems (paints) based on styrene-butadiene copolymer SKS-65GP, BS-30, based on acrylic copolymers DMMA-65GP, as well as Dow Chem styrene-acrylic copolymer, Primal 219N, acrylic MBI-5C, polyurethane.

Hollow microspheres are one of the most important fillers used in the manufacture of plastics. The spherical shape, controlled dimensions and their low density make them often indispensable. An important effect of their use is to reduce the cost of expensive or scarce polymers, as well as a decrease in density. Traditionally, they have a size of 25 to 50 mm and a density of 100 to 700 kg / m ³ .

In the claimed invention, the use of mixtures of hollow microspheres (glass, ceramic, polymer, ash), identical or different in nature, but differing in size in the range from 10 to 500 microns and bulk density in the range from 50 to 650 kg / m ³ allows significantly increase the efficiency of thermal protection and corrosion protection of surfaces (concrete, plaster, metal, wood).

Such properties of hollow microspheres as low oil absorption, inertness and ease of dispersion make them very attractive as fillers.

Hollow microspheres of glass, ceramics, polymers are mainly obtained by introducing a blowing agent into the main material, then grinding them to the desired size and heating them to foam. So, for example, hollow microspheres are obtained by passing small particles containing a porophore through a high temperature zone; the particles melt or soften in the hot zone, and the blowing agent forms a cavity inside the particles, expanding them. When the sphere is cooled in air, its walls harden. Or they can be obtained by foaming glass (or ceramic, ash particles in a burner flame. For example, glass microspheres are used as glass microspheres such as Glass babez type, Microballon type; globumite, spherulite. Ceramic microspheres are also obtained by burning natural materials and foaming; ash or man-made , for example from fly ash.

Polymeric hollow microspheres are usually obtained either by suspension polymerization of monomers with the addition of a blowing agent (porophore, inert gases, low boiling hydrocarbons), or by physical or chemical foaming of the finished polymers in the form of crushed particles. The hollow polymer microspheres in the invention use hollow polystyrene microspheres based on phenol-formaldehyde resins, silicone, urea-formaldehyde, etc.

So, the claimed invention is the use of a composition filled with hollow microspheres, as an anti-corrosion and heat-protective coating on various surfaces. As one of the main components are hollow sieclan, ceramic, polymer, ash (technogenic) microspheres filled with discharged or atmospheric air. The second main component of the applied coating composition is a binder, the function of which is performed by the above aqueous dispersions of polymer resins, which solidify and polymerize after evaporation of water in the dispersion. Microspheres, thoroughly mixed with liquid polymer resins, are an excellent anti-corrosion and heat-protective coating with high adhesive properties. The work of adhesion of this coating to various surfaces, as well as the degree of vapor permeability of the coating is determined by the type of polymer binder used.

For this type of insulating coatings, acrylate, styrene-acrylate, polyurethane, butadiene-styrene, butadiene, polystyrene, vinyl acetate, polyvinyl chloride and other aqueous emulsions (latexes) of polymer resins are used in which microspheres are immersed and mixed. The content of microspheres in the finished composition can be different and vary from 5 to 95 volume%. Latexes can be taken both in pure form or mixed with each other in various proportions to achieve varying degrees of vapor permeability of the resulting coating and the adhesion of the coating to the applied surfaces. For example, when using mixtures of styrene-butadiene and acrylate latexes (the base into which the microspheres are placed), it is possible to obtain coatings with a different degree of vapor permeability - from high permeability to high barrier to water vapor. A mixture with a high content of styrene-butadiene latex has high barrier properties against water vapor, and a mixture containing a large amount of acrylate latex has the properties of good vapor permeability.

To obtain coatings with the least amount of free space between the microspheres and, as a consequence, a high heat-shielding properties must be used a mixture of hollow microspheres of different radii (10 to 500 micrometers) and varying bulk density (from 650 to 50 kg / m ^3). Microspheres with close sizes of the radii of the spheres can also be used, but in this case the degree of filling the space between the spheres will be lower.

The type of polymer binder used for microspheres is important. So in the case of using coatings for high-temperature use (up to + 150 ° C), it is necessary to use polyurethane, acrylate, styrene-acrylate latexes and mixtures thereof. For other types of applications, you can use all of the above (for example, styrene-butadiene, vinyl acetate) or other types of aqueous emulsion latexes, for example copolymer, as well as mixtures thereof. To obtain coatings capable of withstanding repeated temperature drops from -70 to 100 ° C, latex-based mixtures with a high degree of plasticity are used, for example styrene-butadiene, butadiene, polyvinyl chloride, copolymer (based on all the above-mentioned latexes) or mixtures thereof. Polyurethane, acrylate, styrene-acrylate latexes and their mixtures also have high resistance to multiple temperature drops, which do not lead to cracking in the temperature range from -45 to 150 ° C. Highly filled ceramic microspheres coatings have a high ability to reflect and scatter the radiation component of the heat flux incident on the surface. To give the coating even higher properties with respect to the reflection and scattering of incident radiation, including infrared, various whitewash, for example TiO ₂ , ZnO and others, are included in the composition of the mixture. The ability of microspheres to scatter and reflect the light incident on them, including infrared (thermal radiation), is of great importance for this type of coating, since it is able to reflect thermal radiation with a high degree of efficiency up to 95% of the total incident light flux.

If necessary, dispersion and water-soluble dyes are added to the finished mixture, which give the coating the color necessary for the final consumer. In addition, other components are included in the composition of the liquid aqueous emulsion mixture - rust inhibitors and converters, surfactants that stabilize the suspension, prevent the precipitation of individual components with high density into the sediment or the emergence of light microspheres, flame retardants (components that prevent the spread of flame on the finished coating e.g. aluminum trihydrad) and the like.

The finished mixture may have a different viscosity from 1 to 100 Pa · s, however, for better stabilization of the components in a liquid composition, it is better to use high viscosity mixtures. The methods for applying a liquid aqueous emulsion composition can be different, for example, it can be applied using an airless spray gun, brush or roller from one to five layers with thorough drying of each layer before applying the next.

Cooking example

An aqueous emulsion mixture based on styrene-acrylic latex was thoroughly mixed with glass microspheres of three types of sizes (with average microsphere radii of 35, 100 and 200 micrometers with apparent densities of 650, 150, 70 kg / m ³ in a ratio of 3: 6: 1, respectively), possibly titanium dioxide, a surfactant, and also a rust inhibitor. The volume ratio of styrene-acrylic latex to glass microspheres in this case was 1:10. The prepared mixture was applied to a surface, for example, a metal pipe of heat supply, which was filled with superheated water with a pipe surface temperature of + 115 ° C. The prepared mixture is applied to the surface of the pipe using a roller; the thickness of one coating layer was about 0.4 mm. After a day after applying the first layer (the time required to completely dry the coating), the next coating layer is applied to the pipe. The number of layers is determined by the operating conditions of the protected surfaces.

Or, for example, the coating was applied to a metal pipe with a diameter of 33 mm and a length of 90 mm; coating thickness (total) was 3.5 mm. An electric heater was placed inside the tube (s), the power of which varied from 10 to 100 watts. The temperature was measured on the surface of the tube and on the outer surface of the coating. Conductivity is calculated. As a result of measurements, the average thermal conductivity of the coating was 0.089 W / (m · ° С) at 130 ° С, 0.036 W / (m · ° С) at 410 ° С and 0.028 W / (m · ° С) at 750 ° С. Table 1 presents data on temperature changes on the outer surface of the heated tube in contact with the inner surface of the coating (T ₁ ) and on the outer surface of the coating (T ₂ ).

Table 1 T ₁ T ₂ T ₁ -T ₂ T ₁ T ₂ T ₁ -T ₂ T ₁ T ₂ T ₁ -T ₂ one hundred fifty fifty 400 96 304 600 150 450 220 60 160 420 one hundred 320 630 153 477 244 65 179 466 117 349 710 175 535 297 76 221 493 125 368 750 187 563 370 92 278 540 135 405

As a result of the tests, it turned out that over the entire temperature range no cracking of the coating, changes in its color, or peeling from the surface of the tube were observed. The coating is a dense solid mass, firmly adhered to the surface of the metal tube.

The composition according to the invention, the use of which is claimed, can be applied to hot water pipes with a water temperature of about 120 ° C; such pipes usually have a large number of valves and the temperature in the room usually reaches + 45 ° C, which creates unfavorable conditions for workers. The composition according to the claimed invention was used for applying thermal heat supply to such pipes: five coating layers were applied with a total thickness of about 3 mm. As a result, the temperature on the surface of the pipe dropped to 50 ° C and decreased further to + 45 ° C, provided that ambient air flowed into the room, which created more favorable conditions for work, since the room temperature dropped by 15-20 ° C. Moreover, the coating has very high physicomechanical and protective properties 6 its high adhesion to the pipe surface, which primarily provides long-term and reliable corrosion protection of the surface of the hot water pipe.

The composition according to the invention, the use of which is claimed, also provides high anticorrosive and high heat-shielding properties simultaneously when applied to various building structures, for example, on the surface of a hangar. The total surface area of the hangar is about 0.8 square meters; the hangar is coated externally and internally with a coating of the composition, the use of which is the invention. The coating according to the invention is given the code name "Isollat". The thickness of the applied coating is 1.5 mm on each side, the total thickness of the coating is 3 mm; at 40 watts of heater power inside the hangar (layout), the temperature difference between the inner and outer surfaces is 19 ° C; thermal conductivity is about 0.0078 W / (m · ° C).

Coating can be applied by various methods. Table 2 presents examples of the composition, the use of which is claimed as an invention, and table 3 presents averaged data on the main physicomechanical, heat-shielding properties, as well as anticorrosion properties, which are indirectly confirmed by data on vapor, water permeability, adhesion, etc. .

Thus, a coating made of a composition filled with Poland with microspheres in combination with polymer latex as a binder can be applied in rooms with high humidity, on surfaces not designed for volume insulation, when exposed to acids and alkalis (working with them); for coating valves, taps, pumps and other technological equipment (to reduce temperature and noise).

Table 2 presents examples of compositions used to obtain anti-corrosion and thermal insulation coatings according to the invention

table 2 Name of components The content of the components in the examples,% vol. one 2 3 four 1. Polymer binder: 20,0 50,0 40,0 60.0 - polyvinyl acetate latex (50%) 60.0 - 37.0 - - latex dimethylmethacrylate DMMA-1-65-GP - 50,0 - 30,0 - pigments and fillers: - - titanium dioxide - 33.0 - - - lithopone - - 15.0 - - yellow iron oxide pigment - - 2,5 - - talc - - 2,5 - - a piece of chalk - - - - - mummy - - - - - thickener (ethyl cellulose) carboxymethyl cellulose - - 3.0 - - dispersant (sodium polyphosphate) - 4.0 1,0 - - aptiseptic (sodium pentachlorophenolate) - - 2.0 - - corrosion inhibitor (sodium nitrite) - - 3.0 - - coalescing additive - - 1,5 - - surfactant (OP-7) 10.0 5,0 15.0 3.0 - water 30,0 7.0 27.5 67.0 2. A mixture of hollow microspheres: 80.0 50,0 60.0 40,0 - a mixture of glass microspheres: - glass microspheres with a size of 35 microns and density 650 kg / m ³ 24.0 - 30,0 - - glass microspheres with a size of 100 microns and a density of 150 kg / m ³ 48.0 - - - - glass microspheres with a size of 200 microns and a density of 70 kg / m ³ 8.0 30,0 - - a mixture of polymer microspheres: - - polystyrene microspheres with a size of 10 μm and a density of 650 kg / m ³ - 15.0 - 20,0 - polystyrene microspheres with a size of 500 microns and a density of 50 kg / m ³ 5,0 - 20,0 - polystyrene, microspheres with a size of 50 microns and a density of 400 kg / m ³ - 30,0 - -

Table 3
Physical and mechanical properties Tensile strength 80 kgf / cm ² Elongation at break 5% Liquid Density 0.50 kg / dm ³ Finished Density 0.30 kg / dm ³ Vapor permeability 50 gram / m ² / hour Water permeability Less than 30 grams / m ^2/24 hours Light reflection
Light scattering (infrared radiation) 82%
92% Coefficient of thermal resistance by radiation component of thermal conductivity at 2 mm coverage Up to 20 Thermal conductivity for the radiation component of heat transfer 0.001 W / (m ° C) Thermal conductivity for the contact component of heat transfer 0.037 Wt / (m ° C) Adhesion 25 kgf / cm ²

Claims (1)

The use of a water-suspension composition filled with hollow microspheres as an anti-corrosion and heat-insulating coating of pipelines, comprising as a binder a water-emulsion polymer latex composition containing from 10 to 90 vol.% Latex based on a (co) polymer selected from the group comprising (homo ) acrylate copolymer, styrene-acrylate copolymer, styrene-butadiene copolymer, polystyrene, butadiene polymer, polyvinyl chloride polymer, polyurethane polymer, vinyl acetate polymer or copolymer or their mixtures and from 10 to 90 vol.% a mixture of water and a surfactant, and as a filler, the water-suspension composition contains a mixture of hollow microspheres, differing in size from 10 to 500 microns and bulk density from 650 to 50 kg / m ³ and selected from the group comprising hollow glass microspheres, hollow ceramic microspheres, hollow ash (technogenic) microspheres, hollow polymer microspheres or mixtures thereof in the following ratio of components of the water-suspension composition, vol.%: the above polymer latex composition 5-95 the above hollow microspheres 5-95