RU2531191C1 - Polyurea urethane sprayed mastic for obtaining thick-layered anticorrosion coating - Google Patents

Abstract

FIELD: chemistry.

SUBSTANCE: invention relates to a formulation of sprayed double-component polyurea urethane mastic, intended for obtaining primer-free thick-layered isocyanate coatings under conditions of their trace (field) or factory (basic) application and applied, in particular, for anticorrosion protection of an external surface of metal tubes. Mastic is obtained by mixing isocyanate prepolymer with a liquid hydroxylamine hardener with their volume ratio of 1:1. As the prepolymer it contains an oligomer based on polydiphenylmethanepolyisocyanate and polyoxypropylenetriol, and as the liquid hydroxylamine hardener it contains a mixture composition of compounds, which includes the following ingredients with their weight ratio (wt %): 3,3'-dichloro-4,4'-diaminediphenylmethane, polyoxypropylenetriol with molecular, polydiethyleneglycoladipate, N,N'- tetraoxypropyleneethylenediamine, dye fat-soluble black No. 9315 "Nigrosine".

EFFECT: invention provides a possibility of obtaining the thick-layered, frost-resistant polyurea urethane sprayed coating, which has the high level of adhesive, physical-mechanical and exploitation characteristics, without the application of the priming sub-layer.

3 tbl, 9 ex

Description

The invention relates to the formulations of sprayed two-component polyureaurethane mastics, used to obtain thick-layer protective coatings of the barrier type in the conditions of their route or factory application and intended, in particular, for external anti-corrosion protection of metal pipes, shaped pipe fittings, stop valves and mounting units of main and oil and gas pipelines nonlinear pipeline elements and valves of compressor and pumping stations, underground tanks storage of hydrocarbon gas and oil storage facilities with a wide temperature range of operation. For gas pipelines, the lower operating temperature limit is minus 20 ° C, and the characteristics of protective anticorrosion polymer coatings are regulated by the relevant industry requirements of Gazprom, approved in 2005. Oil pipelines can be operated at lower temperatures - up to minus 50 ° C. The quality indicators of their polymer coatings are governed by the requirements of JSC Transneft OTT - 25.220.01-KTN-215-10.

Modern oil and gas pipelines are a complex technical system, which includes not only tubing with a diameter of up to 1420 mm, but also shaped non-linear parts (bends, fittings, tees, elbows, transitions, etc.), shut-off and control valves and mounting units (crane units , valves, plugs, closures, diaphragms, etc.), pipeline elements and fittings of compressor and pump stations, underground storage tanks for natural gas and liquid hydrocarbon product storages, which, like pipes, require reliable long-term protection against corrosion. According to the requirements of the Russian standard GOST R 51164-98, the insulation coatings of the assembly units, valves and fittings according to their characteristics must comply with the characteristics of the main protective coating of the pipes.

The use of modern thick-layer barrier-type insulating coatings at pipeline facilities of oil and gas pipelines of the underground and underwater gaskets provides not only their anticorrosive protection for a long service life, but also protects them from mechanical stress during transportation of pipeline products and during their installation in the field.

A comprehensive anti-corrosion polyurea-urethane coating for pipes and piping details of BIURS oil and gas pipelines is known, including two constituent elements:

- a thin layer primer film, obtained on the basis of a two-pack epoxyurethane primer "Primer-MB", consisting of component A - a solution of an epoxy resin modified with diisocyanate, and component B - an amine hardener;

- a thick outer coating obtained by spraying a two-component biurethane polyurea mastic "BIUR", consisting of component A - isocyanate polymer base containing 13-14 wt.% isocyanate (NCO) groups, and component B - hardener with active hydrogen atoms contained in hydroxyl (OH-) and amino groups (NH ₂ -; -NH-) epoxy polyols and aromatic diamines dissolved in the middle fraction of a coal or shale resin with a viscosity of 18-25 cSt and a basicity of 1.3-1.5 mEq / gHCl [1] .

"Primer-MB" is applied by air or airless spray methods. BIUR mastic is applied to the protected metal surfaces by hot airless spraying with high-pressure apparatuses with separate feeds of components (isocyanate prepolymer base and hydroxylamine hardener) heated to a temperature of 40-80 ° C with their mixing directly in the spraying device.

Based on the combination of adhesive, physical, mechanical, dielectric and operational characteristics, the BIURS complex coating meets the industry requirements of Gazprom and AK Transneft. However, the well-known polyurea-urethane coating is multicomponent and low-tech when applied, since it requires the use of a primer undercoat: the use of only one BIUR mastic does not allow reaching the required level of adhesive characteristics and the stability of a thick-layer coating to the cathode depending on them mu peel volume ratio between the prepolymer and hydroxylamine basis hardener composition known in the mastic is strictly regulated and should be 1:. 1.28, which complicates the design of the material of the pump unit used for pressure vessels airless high viscosity materials.

In addition, coal or shale oils, which are part of one of the components of the mastic, are carcinogenic and environmentally harmful to the human body and the environment.

The closest to the claimed in technical essence and in the recipe is polyurea-urethane two-component mastic, which is part of the Forpol-Oil complex anti-corrosion coating, intended for anti-corrosion protection of metal pipes, shaped fittings, valves and mounting units of oil and gas pipelines of underground and underwater laying, piping and valves of compressor and pumping stations, underground storage tanks, liquefied natural gas and oil storage facilities with a temperature range of operation from minus 30 ° C to plus 60 ° C in the conditions of factory (base) or route (field) coating in the manufacture of pipe parts, construction, reconstruction and overhaul of pipeline facilities. Together with the Forpol-Primer one-component moisture-curing isocyanate primer, the composition of the known mastic for producing an external thick-layer insulating coating contains an isocyanate prepolymer based on diphenylmethanediisocyanate with a mass fraction of NCO groups of 15-17% and a dynamic viscosity at a temperature of (20 ± 3) ° C 3- 10 Pa · s, and a hydroxylamine hardener with active hydrogen atoms with a hydroxyl number of 95-105 mgKOH / g, mass fraction of total titratable nitrogen of 4.2-4.5%, including the following ingredients in their ratio (wt.%):

simple or complex oligoesterdiol with a molecular weight of 800-1000 cu 55-60 hindered diamine with an amine number of 12-16.7 wt.% 35-40 N, N'-tetraoxypropylene ethylenediamine with a hydroxyl number of 640-800 mgKOH / g 3-4 fat soluble organic pigment the rest is up to 100

when the volume ratio "isocyanate prepolymer: hydroxylamine hardener" of 1.3-1.4: 1, providing curing of the thick coating to obtain the desired level of performance [2 - prototype].

The polyurea urethane sprayed mastic according to the prototype, like the previous mastic composition, allows one to obtain external thick-layer coatings that meet the industry requirements of Gazprom and AK Transneft, as well as the requirements of GOST R 51164-98 according to the set of characteristics. However, it also cannot It can be used without a primer, since it does not provide adhesion properties of the resulting coatings to the metal. anticorrosion coatings and expands the range of necessary materials, which is not technologically advanced.The different (unequal) volume ratio between the base and hardener of the mastic (1.3-1.4: 1) leads to the need for the use of metering material pumps of various capacities, which generally complicates the construction of 2- To high-pressure installations for airless spraying of highly viscous compositions.

However, the main disadvantage of the prototype mastic is that the thick-layer anti-corrosion coating obtained on its basis retains its elasticity only to a temperature of minus 30 ° C. In more severe frosts, such a coating is embrittled, losing resistance to shock loads, up to the formation of cracks even without mechanical stress.

The technical problem to be solved within the framework of the present invention is the development of a two-component sprayed mastic, providing a primer-free polyurea-urethane thick-layer coating that meets the set of requirements for the external protective coatings of pipes and pipe components of oil and gas pipelines, the formulations of the reacting components of which provide their equal volume ratio between (1,0: 1,0) for the unification of metering material pumps included in part 2 - To the airless spray unit, and convergence of their viscosity and density in order to improve the uniformity of mixing. In addition, the developed thick-forming mastic should ensure the expansion of the temperature range of operation of coated metal pipe products in the region of negative temperatures - up to minus 50 ° C.

The solution of the above problems is achieved due to the fact that, in contrast to the known composition of the polyureaurethane mastic prototype, the proposed two-component mastic allows to obtain a sprayable primer-free protective coating 1-5 mm thick and contains an isocyanate prepolymer based on polydiphenylmethane polyisocyanate with a mass fraction of NCO groups 17-19 % and a viscosity of 2-5 Pa · s at a temperature of (20 ± 3) ° C, cured with a hydroxylamine hardener with a hydroxyl number of 85-95 mgKOH / g, mass fraction of total titratable nitrogen 3.5-4.0%, including trace better ingredients with their mass ratio to each other (wt.%):

3,3'-dichloro - 4,4'-diaminodiphenylmethane 30-35 polyoxypropylene triol with molecular weighing 5000 cu 12-15 molecular weight polydiethylene glycol adipate weighing 800 cu 47-52 N, N'-tetraoxypropylene ethylenediamine with hydroxyl number 640-800 mgKOH / g 2-4 fat soluble black 9315 "Nigrosine" the rest is up to 100

with a volume ratio of "isocyanate prepolymer: hydroxylamine hardener" - 1.0: 1.0.

The proposed mastic on the protected metal surfaces is applied by the method of "hot" airless spraying of a mixture of components (prepolymer + hardener), heated to the same temperature (40-60 ° C), using 2-K high-pressure plants from WIWA (Germany) or " GRACO "(USA), equipped with a spray device of the" FUSION "system (" GRACO ") and containing metering material pumps of the same capacity for each component.

Due to the use of the used liquid polydiphenylmethane polyisocyanate instead of crystalline diphenylmethane diisocyanate in the synthesis of the isocyanate prepolymer component of the mastic with an increased content of reactive NCO-rpynn (17-19% instead of 13-17% in the prepolymers of the known mastic compositions), its density increased, and the viscosity decreased of the isocyanate prepolymer are practically equal to the corresponding values of the density and viscosity of the hydroxylamine hardener of the above composition wa (table 1).

Table 1 Density and dynamic viscosity of the components of the sprayed mastic Mastic component Temperature ° C Value Density, kg / m ³ Viscosity, Pa · s Isocyanate prepolymer 20 ± 3 1180-1210 2.0-5.0 Isocyanate prepolymer 60 ± 3 - 0.3-0.6 Hydroxylamine hardener 20 ± 3 1200-1220 3.0-6.0 Hydroxylamine hardener 60 ± 3 - 0.2-0.5

This allowed not only dosing the mastic components in equal volumes, but also heating them to the same temperature (40-60 ° C), while improving the uniformity of mixing the components in the spray device, resulting in thick polymer coatings with isotropic properties throughout the thickness.

An equal volume ratio between the components of the mastic also ensures an optimal molar ratio between the reactive groups of the prepolymer (NCO) and hardener (the sum of NH ₂ + OH), equal to ~ 1.2 / 1.0 (mol of NCO / mol (NH ₂ + OH).

Polydiethylene glycol adipate with a molecular weight of 800 cu to obtain the hardener used brand "PDA-800" according to TU 38.103287-80. Polyoxypropylene-phenol with a molecular weight of 5,000 cu for the same purpose, the Laprol-5003-2-15 brands (TU 2226-006-10488057-94) or its imported analogues of the Voranol CP 4711, Volanol CP 4702 type were used. As an aromatic diamine - 3,3'-dichloro-4,4'-diaminodiphemelmethane, we used the domestic product of the Dia-X brand (TU 6-14-980-84) or its imported analogues - Kuamine-K, MOSA "

N, N'-Tetraoxypropylenediamine was used either domestically or imported - Lapromol-294 (TU 6-05-1681-80), Voranol RA-640, or Voranol RA-800. Fat-soluble dye used black - No. 9315 "Nigrosine" (import).

Upon receipt of the isocyanate prepolymer component of the mastic, polydiphenylmethane polyisocyanate with a mass fraction of NCO groups of 30-32 wt.% And a functionality of 2.70-2.85 from foreign manufacturers was used: Voranat M229, Vorakor SD 345, Desmodur VL, Vannate RM-200 "or others, and together with it used polyoxypropylene triol with a molecular weight of 5000 cu Laprol-5003-2-15 or Voranol CP 4711; CP 4702 brands.

The isocyanate prepolymer and hydroxylamine hardener of the proposed mastic are manufactured using standard capacitive chemical equipment equipped with a mechanical mixing device and heated with a jacket or coil with a coolant, providing intensive mixing of the contents of the reactor during the synthesis of the prepolymer and obtaining the hardener and its heating to a temperature of 100-110 ° C with the possibility of subsequent cooling to the temperature of the production room.

Comparison of the proposed thick-forming polyureaurethane mastic with known mastic compositions of a similar technical purpose allows us to draw a reasonable conclusion about its compliance with the inventive criterion of "Novelty", since in this case a new combination of mastic components is contained: an oligomer with a different content of NCO groups is used as an isocyanate prepolymer (17 -19 wt.% Instead of 13-17 wt.%), Obtained in addition not from monomeric crystalline diphenylmethanediisocyanate, but from a liquid polymer olidiphenylmethane polyisocyanate, and for the first time a liquid homogeneous mixture of diamine and oligoester polyols with active hydrogen atoms with a concentration of hydroxyl groups of 85-95 mgKOH / g and a total titrated nitrogen content of 3.5-4.0 wt.% is used as the hydroxylamine hardener.

The combination of the above innovations led to a new non-obvious effect - the possibility of obtaining a primer-free anticorrosive coating of an insulating type that retains its elasticity and resistance to shock loads in the operating temperature range from minus 50 ° C to plus 60 ° C, which is also resistant to cathodic peeling and more high adhesion to a metal substrate without the use of a primer sublayer with long-term preservation of the basic regulated physical and mechanical and operational tion characteristics. The above indicates that the proposed technical solution meets the criterion of "Inventive step".

The proposed formulations of mastic components are focused on the use of ingredients of both domestic and foreign production, produced on an industrial scale, using standard chemical reactor equipment to produce them. Mastic is applied to the protected metal surfaces in both factory and highway conditions using the airless machine spraying method using the existing 2-K installations for hot airless spraying of highly viscous materials. This allows you to make a reasonable conclusion about the conformity of the proposed technical solution to the criterion of "Industrial applicability".

Coating samples for tests were prepared on metal plates made of steel grade St.3 with a size of 150 × 150 × 5-6 mm as follows: the plates were previously subjected to blast cleaning using cupro slag or nickel slag with an abrasive particle size of 1.5-3.0 as an abrasive mm to obtain a surface roughness (R _z ) of 50-120 μm, after which the treated plates were dust-free and degreased with solvent. Then, using a 2-K high-pressure installation "DVOMIX-230"("WIWA"), polyureaurethane mastic 2.5-3.0 mm thick was sprayed onto the prepared plates. The temperature of both components was (50 ± 10) ° C.

A free film of cured polyureaurethane mastic for determining the physicomechanical and other characteristics was obtained by spraying it on fluoroplastic sheets.

All tests were carried out 5 days after coating in accordance with the methods set forth in the appendices to GOST R 51164-98. "Steel main pipelines. General requirements for corrosion protection."

The technical nature and advantages of the proposed polyurea mastic are illustrated by the following experimental data.

EXAMPLES 1-9.

Table 2 shows the formulations and characteristics of isocyanate prepolymers and hydroxylamine hardeners, which are part of the proposed mastic and mastic - prototype, and table 3 shows the test results obtained on their basis of thick-layer polyurea coatings.

Note: the volume ratio between the isocyanate prepolymer and the hydroxylamine hardener in the composition of the mastic prototype was 1.3: 1.0 (1.25: 1.0 by weight).

Table 3 Properties of polyureaurethane coatings The name of indicators №№Examples from table.2 1 (prototype) 2 3 four 5 6 7 8 9 one 2 3 four 5 6 7 8 9 10 1. Initial adhesion to steel St.3 by the method of normal separation at a temperature of (20 ± 3) ° C, MPa 13.5 14.1 17.6 22.4 8.7 14.7 16.1 15.1 16.5

one 2 3 four 5 6 7 8 9 10 2. Decrease in adhesion to steel St.3 after holding samples in water at a temperature of (60 ± 3) ° C for 1000 h,% of the initial value 22.0 27.0 24.5 20.3 38,2 19,2 18.3 18.2 17.1 3. The resistance of the coating to cathodic peeling after exposure to a 3% NaCl solution at a temperature of (20 ± 3) ° C for 30 days, cm ² 1.20 1.80 1,60 1.90 4.90 1.05 1,03 1.00 1,11 4. Penetration resistance at a temperature of (20 ± 3) ° C, mm 0.22 0.16 0.14 0.08 0.35 0.22 0.30 0.25 0.28 5. The strength of the free film at break at a temperature of (20 ± 3) ^° C, MPa 19.6 23.8 25,4 28.9 12,2 15.3 18.2 15,5 19,2 6. Elongation at break at a temperature of (20 ± 3) ° C,% 81.0 78,2 66.7 53.5 108,0 95.3 92.4 94.8 90.0 7. Shore-A hardness, conventional units 96 97 97 99 91 95 94 95 95 8. The strength of the coating upon impact, J / mm, at temperatures: Minus 50 ° C 1.8 8.3 7.4 6.2 7.0 3.4 2,8 3.0 2.9 Minus 30 ° C 4.9 10.8 9.3 7.8 8.2 6.3 5,4 5,4 5,6 plus 20 ° C 6.2 12,4 10,2 10.7 9.6 8.0 8.2 8.3 8.5 plus 40 ° C 6.0 9.8 8.2 8.3 9.2 7.2 7.7 7.0 7.4

Thus, as can be seen from the above experimental data, the proposed composition of the sprayed polyureaurethane mastic, due to the combination of the properties of the above isocyanate prepolymer and liquid hydroxylamine hardener, mixed in a volume ratio of 1: 1, allows the use of a primer undercoat to obtain a thick-layer anticorrosive coating for pipes and pipe products of oil and gas pipelines, which retains elasticity and is resistant to shock loads at low temperatures - up to minus 50 ° C, in The difference from the prototype mastic, the coating on the basis of which is resistant to impact only to a temperature of minus 30 ° C, and having at the same time an acceptable level of adhesive, physical, mechanical and other operational characteristics regulated by existing technological requirements.

The same volume ratio between the components of the mastic and the absence of a primer reduces the assortment of materials used, simplifies and speeds up the process of spraying a protective thick-layer coating, and allows using 2-K airless spraying plants of a simpler design due to the unification of metering material pumps.

The proposed mastic can be used for repair work on existing oil and gas pipelines during their re-isolation.

Information sources

1. Patent No. 2216561 (RF). IPC ⁷ C09B 5/08; C09D 175/04. Claim March 4, 2002, application No. 2002106194/04. Publ. 11/20/2003.

2. Patent No. 2428443 (RF). IPC ⁸ C09D 5/08; C09D 175/02; C09D 175/04. Claim 03/16/2010, application No.2010110458 / 05. Publ. 09/10/2011. - The prototype.

Claims (1)

Polyurea-urethane sprayed mastic for producing a thick-layer anticorrosive coating intended for external insulation in factory or route conditions of metal pipes, stop valves and non-linear pipe products of oil and gas pipelines operating in the temperature range from minus 50 ° C to plus 60 ° C, containing isocyanate prepolymer and liquid hydroxylamine solid with reactive hydroxyl and amine groups, characterized in that as an isocyanate prepolymer it contains ph a polymer with a viscosity of 2-5 Pa · s at a temperature of (20 ± 3) ° C and a mass fraction of isocyanate groups of 17-19 wt.%, obtained on the basis of polydiphenylmethane polyisocyanate and polyoxypropylene triol with a molecular weight of 5,000 cu, and as liquid hydroxylamine hardener mixed composition of chemical compounds with a hydroxyl number of 85-95 mgKOH / g and a mass fraction of total titratable nitrogen of 3.5-4.0 wt.%, including the following ingredients in their mass ratio (wt.%):
3,3'-dichloro-4,4'-diaminodiphenylmethane 30-35 polyoxypropylene triol with molecular weighing 5000 cu 12-15 polydiethylene glycol adipate with molecular weight 800 cu 47-52 N, N'-tetraoxypropylene ethylenediamine with a hydroxyl number of 640-800 mgKOH / g 2-4 fat soluble black No. 9315 "Nigrosin" the rest is up to 100
when the volume ratio "isocyanate copolymer: hydroxylamine hardener" is 1: 1.