CN120383733A - A preparation method of modified silicone resin and heavy-duty anti-corrosion powder coating and its preparation method and application - Google Patents

Abstract

The present invention provides a preparation method of a modified silicone resin and a heavy-duty anti-corrosion powder coating, as well as a preparation method and application thereof, and relates to the technical field of functional coatings. The modified silicone resin prepared by the present invention is a special silicone resin that can be cured with dicyandiamide, and is compounded with epoxy resin and linear phenolic epoxy resin as the main film-forming substance of the coating. The use of modified dicyandiamide as a curing agent can greatly improve the acid boiling resistance and high temperature resistance of epoxy powder coatings, and significantly improve the long-term protective performance of epoxy powder coatings under extreme conditions of high temperature and high pressure. The present invention provides a heavy-duty anti-corrosion powder coating. The heavy-duty anti-corrosion powder coating provided by the present invention is an integrated wear-resistant and anti-corrosion coating with excellent interface bonding properties, and is particularly suitable for the long-term protection of oilfield pipelines under high temperature, high pressure and strong corrosion conditions.

Description

Preparation method of modified organic silicon resin, heavy-duty anticorrosive powder coating, and preparation method and application thereof

Technical Field

The invention relates to the technical field of functional coatings, in particular to a preparation method of modified organic silicon resin, a heavy-duty anticorrosive powder coating, and a preparation method and application thereof.

Background

The corrosion prevention of the underground oil pipe of the oil and gas field plays a vital role in the petroleum industry, can prolong the service life of the oil pipe, improve the production efficiency and ensure the safe transportation of oil gas.

The epoxy powder coating is one of the most commonly used oil pipe anti-corrosion materials, and the traditional epoxy powder coating is generally prepared by adding pigment and filler and functional auxiliary agent by adopting one or a combination of more of epoxy resin, polyester resin, acrylic resin and phenolic resin. However, the traditional epoxy powder coating is easy to generate a failure chain of 'coating bubbling-medium permeation-interfacial peeling' under the high-temperature high-pressure dynamic working condition of an oil field, and particularly for deep well oil field pipelines (including oil pipes, oil extraction rods and the like) with the well depth of more than 5000 meters, the working condition is that corrosive mediums coexist at the temperature of 150-220 ℃, the pressure of 15-50 MPa and the H ₂S/CO₂, and the condition is more severe. The traditional epoxy powder coating is difficult to meet the long-acting protective performance under extreme working conditions.

Disclosure of Invention

In view of the above, the invention aims to provide a preparation method of modified organic silicon resin, a heavy-duty anticorrosive powder coating, and a preparation method and application thereof. The modified organic silicon resin prepared by the invention is beneficial to improving the long-acting protective performance of the epoxy powder coating under the extreme working conditions of high temperature and high pressure.

In order to achieve the above object, the present invention provides the following technical solutions:

The invention provides a preparation method of modified organic silicon resin, which comprises the following steps:

Mixing methyltrimethoxysilane, phenyltriethoxysilane and isocyanatopropyl triethoxysilane with an alcohol-water solvent for hydrolytic polycondensation to obtain a solution containing terminal isocyanate polysiloxane, wherein the hydrolytic polycondensation is carried out under the condition that the pH value is 3-6;

Mixing the solution containing isocyanate groups with dicyandiamide and amino cage-type silsesquioxane to carry out hybridization crosslinking polycondensation reaction to obtain a solution containing Si, O, C and N hybridization crosslinking polymers;

And removing the solvent from the solution containing the Si, O, C and N hybrid cross-linked polymer to obtain the modified organic silicon resin.

Preferably, 60-80 parts by mass of methyltrimethoxysilane, 20-40 parts by mass of phenyltriethoxysilane, 15-25 parts by mass of isocyanatopropyl triethoxysilane, 10-20 parts by mass of dicyandiamide and 5-10 parts by mass of aminated cage-type silsesquioxane.

Preferably, the temperature of the hydrolytic polycondensation is 50-80 ℃ and the time is 2-4 hours, and the temperature of the hybridization crosslinking polycondensation reaction is 60-100 ℃ and the time is 2-6 hours.

The invention provides a heavy-duty anticorrosive powder coating, which comprises the following preparation raw materials in percentage by mass:

15-35% of epoxy resin, 5-15% of linear phenolic epoxy resin, 15-25% of modified organic silicon resin, 2-5% of graphene modified silicon titanium nano polymer slurry, 15-25% of wear-resistant reinforcing filler, 1-10% of mica powder, 0.5-2% of pigment, 0.1-0.3% of hydrophobic interface modifier, 0.1-1% of fumed silica, 5-15% of silica micropowder, 0.5-1.5% of dispersing agent, 0.5-1.5% of wetting agent, 0.5-1.5% of defoaming agent, 0.4-1.5% of conductive agent, 0.5-1.5% of adhesion promoter, 0.5-1.5% of leveling agent and 1-5% of dicyandiamide curing agent;

the wear-resistant reinforcing filler comprises carbide and/or metal oxide, the hydrophobic interface modifier comprises fluorocarbon silane coupling agent and/or modified polysiloxane copolymer, and the modified organic silicon resin is prepared by the preparation method according to the technical scheme;

the graphene modified silicon titanium nano polymer slurry comprises, by mass, 40-60 parts of titanium hydride, 2-5 parts of active silicon dioxide, 1-2 parts of silane coupling agent modified graphene, 10-30 parts of silicon modified epoxy resin, 3-6 parts of active diluent, 2-10 parts of N-methylpyrrolidone, 1-5 parts of dispersing agent, 1-5 parts of coupling agent, 0.01-0.1 part of catalyst, 0.1-0.2 part of wetting agent and 0.1-0.2 part of wetting auxiliary agent.

Preferably, the epoxy equivalent of the epoxy resin is 600-1800.

Preferably, the carbide comprises one or more of silicon carbide, titanium carbide and tungsten carbide, and the metal oxide comprises zirconia and/or ceramic alumina.

Preferably, the fluorocarbon silane coupling agent comprises a heptadecafluorodecyl triethoxysilane coupling agent, and the modified polysiloxane copolymer comprises a polyether siloxane.

Preferably, the particle size of the heavy-duty powder coating is less than 70 microns, and the mass ratio of the particles with the particle size less than 50 microns is more than or equal to 80%.

The invention provides a preparation method of the heavy-duty anticorrosive powder coating, which comprises the following steps:

Premixing graphene modified silicon-titanium nano polymer slurry with a hydrophobic interface modifier to form hydrophobized premix slurry;

Mixing the hydrophobization premixed slurry with wear-resistant reinforcing filler to form core-shell structure slurry;

and mixing the core-shell structure slurry with epoxy resin, linear phenolic epoxy resin, modified organic silicon resin, pigment, mica powder, fumed silica, silicon micropowder, dispersing agent, wetting agent, defoamer, conductive agent, adhesion promoter, leveling agent and dicyandiamide curing agent, and carrying out melt extrusion on the obtained mixture to obtain powder, thereby obtaining the heavy-duty anticorrosive powder coating.

The invention provides the application of the heavy-duty powder coating prepared by the technical scheme or the preparation method of the technical scheme in oilfield pipeline corrosion prevention.

The invention provides a preparation method of modified organic silicon resin, which comprises the steps of firstly hydrolyzing and condensing methyltrimethoxysilane, phenyltriethoxysilane and isocyanatopropyl triethoxysilane to form isocyanate-terminated polysiloxane, wherein the methyltrimethoxysilane, the phenyltriethoxysilane and the isocyanatopropyl triethoxysilane have the hardness, the flexibility and the heat resistance, and the isocyanate-terminated polysiloxane is bridged by dicyandiamide and amino cage-shaped silsesquioxane (NH ₂ -POSS) to form a hybrid network, so that the problem of poor compatibility of dicyandiamide and resin is solved, the organic silicon has high crosslinking density (the crosslinking density can reach more than 95 percent) after being solidified, the heat resistance and the pressure resistance of the resin are excellent, and the introduction of an NH ₂ -POSS nano reinforcing structure can further inhibit thermal oxidative degradation. The modified organic silicon resin prepared by the invention is dicyandiamide-curable organic silicon special resin, the thermal decomposition temperature of the cured resin reaches above 480 ℃, the coating is complete under 600 ℃/100h high-temperature test (GB/T1735-2009), the modified organic silicon resin is compounded with epoxy resin and novolac epoxy resin to be used as main film forming substances of the coating, and the dicyandiamide curing agent is adopted, so that the acid boiling resistance and the high temperature resistance of the epoxy powder coating can be greatly improved, and the long-acting protective performance of the epoxy powder coating under high-temperature high-pressure extreme working conditions is remarkably improved.

The invention provides a heavy-duty anticorrosive powder coating which comprises, by mass, 15-35% of epoxy resin, 5-15% of novolac epoxy resin, 15-25% of modified organic silicon resin, 2-5% of graphene silicon titanium nano slurry, 15-25% of wear-resistant reinforcing filler, 1-10% of mica powder, 0.5-2% of pigment, 0.1-0.3% of hydrophobic interface modifier, 0.1-1% of fumed silica, 5-15% of silica micropowder, 0.5-1.5% of dispersing agent, 0.5-1.5% of wetting agent, 0.5-1.5% of defoaming agent, 0.4-1.5% of conductive agent, 0.5-1.5% of adhesion promoter, 0.5-1.5% of leveling agent and 1-5% of dicyandiamide curing agent. In the invention, the modified organic silicon resin is dicyandiamide-curable organic silicon special resin, is compounded with epoxy resin and novolac epoxy resin to be used as a main film forming substance of the coating, greatly improves the high temperature resistance of the coating, simultaneously maintains the excellent adhesive force and chemical resistance of the epoxy resin and the novolac resin, can coat solid particles in graphene-modified silicon titanium nano polymer slurry, can adsorb and anchor resin and coupling agent in the graphene-modified silicon titanium nano polymer slurry to form a nucleation shell structure on the surface of the wear-resistant reinforced filler, ensures the cross-linkable property of the dicyandiamide curing of the shell and main resin in the powder coating formula, optimizes the dispersion and stability of hard phase wear-resistant components, ensures the ultra-high compactness of the coating, ensures excellent hardening wear resistance, simultaneously improves the overall hydrophobicity of the coating, improves the wetting and penetrating capacities of various acid-alkali salt ions in water resistance and water resistance, and improves the compactness of the powder coating, and improves the crosslinking strength and the curing performance of other powder coating. The heavy-duty powder coating provided by the invention is a wear-resistant and corrosion-resistant integrated coating with excellent interface bonding performance, and can realize long-term protection of the coating under extreme working conditions.

The results of the examples show that the heavy-duty powder coating provided by the invention has the wear resistance of more than or equal to 2.2L/mu m (shakeout method), the adhesion of 5A grade (3A grade better than the standard requirement), the corrosion resistance of 10% HCl (room temperature, 90 days), the coating of no change, 3.5% NaCl (room temperature, 90 days), the coating of no change, the crude oil (80 ℃ C., 90 days), the coating of no change, the high-temperature high-pressure performance of 1:180 ℃ per 70MPa/16h (NaOH solution, pH=12.5), the condition of 2:107 ℃ per 35MPa/16h (water/toluene/kerosene mixed solution), and the adhesion of 5A grade is maintained as a result of no bubbles in the coating. And the heavy-duty powder coating has no foaming, has 1-grade adhesive force and shows excellent long-acting protective performance under extreme working conditions through high-temperature high-pressure simulation test of 220 ℃ per 35MPa H ₂ S saturated aqueous solution (720H).

The invention provides a preparation method of the heavy-duty anticorrosive powder coating, which adopts a multistage dispersion design, wherein a hydrophobic interface modifier can firstly coat solid particles in graphene modified silicon-titanium nano polymer slurry to form hydrophobic premix slurry, the hydrophobic interface modifier and a coupling agent in the slurry have good compatibility and can be mutually crosslinked to ensure that the hydrophobic interface modifier is not easy to migrate, then the hydrophobic premix slurry is mixed with wear-resistant reinforcing filler, and resin and the coupling agent in the graphene modified silicon-titanium nano polymer slurry are adsorbed and anchored on the surface of the wear-resistant reinforcing filler to form a nucleation shell structure, so that the multiphase compatibility and compactness of the coating are effectively improved, and meanwhile, the hydrophobic interface modifier and the graphene silicon-titanium nano slurry are more uniformly distributed among hard phase particles of the coating.

The invention provides the application of the heavy-duty powder coating prepared by the technical scheme or the preparation method of the technical scheme in oilfield pipeline corrosion prevention. The heavy-duty powder coating provided by the invention is particularly suitable for long-acting protection of oilfield pipelines under the working conditions of high temperature, high pressure and strong corrosion.

Drawings

FIG. 1 is an electron microscope image (a) of a common epoxy powder coating after abrasion resistance test and an electron microscope image (b) of a heavy anti-corrosion powder coating obtained in comparative example 1 after abrasion resistance test;

FIG. 2 is an electron microscope image (a) of a common powder coating layer after abrasion resistance test and an electron microscope image (b) of a heavy anti-corrosion powder coating layer obtained by multistage dispersion in example 1 after abrasion resistance test;

FIG. 3 is the appearance of a heavy duty powder coating obtained by multistage dispersion of example 1.

Detailed Description

The invention provides a preparation method of modified organic silicon resin, which comprises the following steps:

Mixing methyltrimethoxysilane, phenyltriethoxysilane and isocyanatopropyl triethoxysilane with an alcohol-water solvent for hydrolytic polycondensation to obtain a solution containing terminal isocyanate polysiloxane, wherein the hydrolytic polycondensation is carried out under the condition that the pH value is 3-6;

Mixing the solution containing isocyanate groups with dicyandiamide and amino cage-type silsesquioxane to carry out hybridization crosslinking polycondensation reaction to obtain a solution containing Si, O, C and N hybridization crosslinking polymers;

And removing the solvent from the solution containing the Si, O, C and N hybrid cross-linked polymer to obtain the modified organic silicon resin.

In the present invention, unless otherwise specified, the raw materials involved are commercially available products well known in the art.

The invention mixes methyltrimethoxysilane (MTMS), phenyltriethoxysilane (PTES) and isocyanatopropyl triethoxysilane (IPTS) with alcohol-water solvent to carry out hydrolytic polycondensation to obtain solution containing isocyanate polysiloxane.

In the invention, the methyltrimethoxysilane, the phenyltriethoxysilane and the isocyanatopropyl triethoxysilane can achieve good hardness, flexibility and heat resistance of the coating, and the prepared resin has proper viscosity. In the present invention, the alcohol in the alcohol-water solvent is preferably ethanol, and the volume ratio of the alcohol to water is preferably 95:5. In the invention, the hydrolytic polycondensation is carried out under the condition that the pH value is 3-6, wherein the pH value can be 3, 4, 4.5, 5 or 6, and the invention preferably adds methyltrimethoxysilane, phenyltriethoxysilane and isocyanatopropyl triethoxysilane into an alcohol-water solvent with the pH value of 3-6 for hydrolytic polycondensation. In the invention, the temperature of the hydrolytic polycondensation is preferably 50-80 ℃, can be 50, 60, 70 or 80 ℃, and the time is preferably 2-4 h, can be 2, 3 or 4h, and the hydrolytic polycondensation is preferably carried out under the condition of stirring. The reactions involved in the hydrolytic polycondensation are as follows (note: isocyanate groups (-NCO) are stable under acidic conditions, do not participate in hydrolysis):

MTMS hydrolysis CH ₃Si(OCH₃)₃+3H₂O→CH₃Si(OH)₃+3CH₃ OH;

hydrolysis of PTES ：C₆H₅Si(OCH₂CH₃)₃+3H₂O→C₆H₅Si(OH)₃+3CH₃CH₂OH;

IPTS hydrolysis ：(NCO)C₃H₆Si(OCH₂CH₃)₃+3H₂O→(NCO)C₃H₆Si(OH)₃+3CH₃CH₂OH;

In the polycondensation stage, si-O-Si bonds are formed between silanol by dehydration condensation, and isocyanate silanol (IPTS hydrolysate) is taken as a blocking agent to occupy the tail end of a polymer chain.

After the solution containing the isocyanate groups is obtained, the solution containing the isocyanate groups is mixed with dicyandiamide and amino cage type silsesquioxane (or amino cage type polysilsesquioxane, NH ₂ -POSS) for hybridization crosslinking polycondensation reaction to obtain the solution containing Si, O, C and N hybridization (marked as Si-O-C-N hybridization) polymer.

In the present embodiment, the NH ₂ -POSS is available from Sean Azithro Biotech Inc. In the invention, the temperature of the hybridization cross-linking polycondensation reaction is preferably 60-100 ℃, can be 70, 80 or 90 ℃, and the time is preferably 2-6 h, can be 3, 4 or 5h. In the invention, dicyandiamide and NH ₂ -POSS are preferably added into the solution containing isocyanate polysiloxane, and the temperature is raised to 60-100 ℃ for hybridization crosslinking polycondensation reaction. During the hybrid crosslinking polycondensation reaction, the reactions involved are as follows:

pre-reaction of dicyandiamide (DCD) with isocyanatosilane:

amino groups (-NH ₂) of dicyandiamide ((NH ₂)₂ c=n-c≡n) are first reacted with isocyanate groups (-NCO) of isocyanate-terminated polysiloxanes, the formation of a urea linkage (-NH-CO-NH-) bridged structure (R-NH-C (=o) -NH) ₂ c=n-c≡n:

(NH ₂)₂C＝N-C≡N+2R-NCO→(R-NH-C(＝O)-NH)₂ c=n-c≡n (R is the organosilicon moiety of a silane, e.g. -C ₃H₆Si(OH)₃), this step is a preliminary chemical bonding of the siloxane backbone to dicyandiamide, forming an organic-inorganic hybrid precursor, the two amino groups of dicyandiamide preferentially react with the-NCO of the terminal isocyanatopolysiloxane, while the terminal cyano groups remain for subsequent condensation with NH ₂ -POSS.

Amino group of NH ₂ -POSS reacts with cyano group of dicyandiamide:

The amino (-NH ₂) of NH ₂ -POSS and cyano (-C≡N) in the pre-reaction product undergo nucleophilic addition reaction to generate POSS with imine bond (-NH-C=N-) which can anchor the POSS nano structure into the organic silicon resin network through condensation of cyano and amino, and finally form a hybrid network containing Si, O, C and N.

In the present invention, the viscosity of the solution containing the Si, O, C and N hybrid polymer is preferably 2000 to 6000mpa·s, and may be 2500, 3000, 4000 or 5000mpa·s.

After the solution containing the Si, O, C and N hybrid polymer is obtained, the solvent of the solution containing the Si, O, C and N hybrid polymer is removed, and the modified organic silicon resin is obtained.

In the invention, the methyltrimethoxysilane is preferably 60-80 parts by weight and can be 60, 70 or 80 parts by weight, the phenyltriethoxysilane is preferably 20-40 parts by weight and can be 20, 30 or 40 parts by weight, the isocyanatopropyl triethoxysilane is preferably 15-25 parts by weight and can be 15, 20 or 25 parts by weight, the dicyandiamide is preferably 10-20 parts by weight and can be 10, 15 or 20 parts by weight, and the aminated cage type silsesquioxane is preferably 5-10 parts by weight and can be 5, 6, 7, 8, 9 or 10 parts by weight.

In the present invention, the solvent removal method may be vacuum distillation, and the temperature of the vacuum distillation may be 120 ℃. After the solvent is removed, the obtained material is preferably crushed to obtain the powdery modified organic silicon resin.

The modified organic silicon resin prepared by the invention is organic silicon special resin capable of being cured by dicyandiamide, is compounded with epoxy resin and novolac epoxy resin to be used as main film forming substances of the coating, and adopts dicyandiamide curing agent, so that the acid boiling resistance and high temperature resistance of the epoxy powder coating can be greatly improved, and the long-acting protective performance of the epoxy powder coating under high-temperature high-pressure extreme working conditions can be remarkably improved.

The invention provides a heavy-duty anticorrosive powder coating, which comprises the following preparation raw materials in percentage by mass:

15-35% of epoxy resin, 5-15% of linear phenolic epoxy resin, 2-5% of modified organic silicon resin, 2-5% of graphene silicon titanium nano slurry, 15-25% of wear-resistant reinforcing filler, 1-10% of mica powder, 0.5-2% of pigment, 0.1-0.3% of hydrophobic interface modifier, 0.1-1% of fumed silica, 5-15% of silica micropowder, 0.5-1.5% of dispersing agent, 0.5-1.5% of wetting agent, 0.5-1.5% of defoaming agent, 0.4-1.5% of conductive agent, 0.5-1.5% of adhesion promoter, 0.5-1.5% of leveling agent and 1-5% of dicyandiamide curing agent;

the wear-resistant reinforcing filler comprises carbide and/or metal oxide, the hydrophobic interface modifier comprises fluorine-containing silane coupling agent and/or modified polysiloxane copolymer, and the modified organic silicon resin is prepared by the preparation method according to the technical scheme.

The preparation raw materials of the heavy-duty powder coating provided by the invention comprise 15-35% of epoxy resin, which can be 20%, 30%, 33% or 34% by mass. In the invention, the epoxy equivalent of the epoxy resin is preferably 600-1800, and can be 600-650, 700-750, 780-850 or 1500-1800, and the epoxy resin is favorable for balancing melt viscosity, reactivity, coating toughness and the like.

The preparation raw materials of the heavy-duty powder coating provided by the invention comprise 5-15% of novolac epoxy resin, which can be 7%, 8% or 10% by mass. In the present invention, the phenolic novolac epoxy resin is preferably available from Hunan Severe materials science, inc. under the designation R-0273. In the invention, the phenolic novolac epoxy resin can improve the flexibility, chemical resistance and steaming resistance of the coating.

The preparation raw materials of the heavy-duty anticorrosive powder coating comprise 15-25% of modified organic silicon resin, which can be 15%, 20% or 25%, by mass percent, and the modified organic silicon resin prepared by the preparation method of the technical scheme. In the invention, the modified organic silicon resin is organic silicon special resin capable of being cured by dicyandiamide, and is compounded with epoxy resin and novolac epoxy resin to be used as a main film forming substance of the coating, so that the high temperature resistance of the coating is greatly improved, and meanwhile, the excellent adhesive force and chemical resistance of the epoxy resin and the novolac resin are maintained.

The preparation raw materials of the heavy-duty anticorrosive powder coating provided by the invention comprise 2-5% of graphene modified silicon-titanium nano polymer slurry, which can be 2%, 3%, 4% or 5%. The graphene-modified silicon titanium nano polymer slurry comprises, by mass, 40-60 parts of titanium hydride, 2-5 parts of active silicon dioxide, 1-2 parts of silane coupling agent-modified graphene, 10-30 parts of silicon-modified epoxy resin, 3-6 parts of active diluent, 2-10 parts of N-methylpyrrolidone, 1-5 parts of dispersing agent, 1-5 parts of coupling agent, 0.01-0.1 part of catalyst, 0.1-0.2 part of wetting agent and 0.1-0.2 part of wetting aid, wherein the graphene-modified silicon titanium nano polymer slurry specifically refers to China patent CN113416469A (application number 202110788222.4). In the invention, the modified graphene silicon titanium nano polymer slurry can be subjected to crosslinking reaction with dicyandiamide, and the formed nano polymer network structure is distributed in the coating and is mainly used for improving the compactness and permeation resistance of the whole coating.

The heavy-duty anticorrosive powder coating provided by the invention comprises 15-25% of wear-resistant reinforcing filler, which can be 15%, 17%, 18%, 20% or 25% by mass. In the invention, the wear-resistant reinforcing filler comprises carbide and/or metal oxide, wherein the carbide preferably comprises one or more of silicon carbide, titanium carbide and tungsten carbide, the metal oxide preferably comprises zirconia and/or ceramic alumina, and when the wear-resistant reinforcing filler comprises carbide and metal oxide, the mass ratio of the carbide to the metal oxide is preferably 1:2-2.4. In the present invention, the particle size of the carbide is preferably 1250 to 3000 mesh, and the particle size of the metal oxide is preferably 1250 to 2000 mesh. In the invention, the silicon carbide mainly plays a role in wear resistance, and the metal oxide plays a role in wear resistance and acid, alkali and salt corrosion resistance.

The preparation raw materials of the heavy-duty powder coating provided by the invention comprise 1-10% of mica powder, which can be 1%, 5% or 10% by mass. In the invention, the mica powder is preferably mica powder GA-4 (purchased from Anhui Gray New Material technology Co., ltd.) which has a flaky structure, and can improve the anti-cracking and anti-permeation effects while improving the wear resistance of the coating.

The heavy-duty anticorrosive powder coating provided by the invention comprises 0.5-2% of pigment, which can be 0.5%, 1% or 2% of pigment. In the present invention, the pigment is preferably carbon black, which may be cabot 660R, and the pigment is used for color matching.

The preparation raw materials of the heavy-duty anticorrosive powder coating comprise 0.1-0.3% of hydrophobic interface modifier, which can be 0.1%, 0.2% or 0.3% by mass. In the present invention, the hydrophobic interface modifier comprises a fluorocarbon silane coupling agent, preferably comprising a heptadecafluorodecyl triethoxysilane coupling agent, and/or a modified polysiloxane copolymer, preferably comprising a polyether siloxane, which may be a di-high 450. In the invention, the hydrophobic interface modifier can improve the hydrophobicity of the coating and reduce the penetration of water and ions in the water.

The heavy-duty anticorrosive powder coating provided by the invention comprises 0.1-1% of fumed silica, which can be 0.1%, 0.2%, 0.5% or 1% by mass. In the invention, the fumed silica is preferably fumed silica R974 (Desoxhlet), and the fumed silica enables the powder coating to have better fluidity, is easy to spray, and simultaneously helps to improve the hydrophobicity of the coating and has anti-sagging effect.

The preparation raw materials of the heavy-duty anticorrosive powder coating comprise 5-15% of silicon micropowder, which can be 5%, 8%, 10% or 15% by mass. In the invention, the particle size of the silicon micro powder is preferably 1250-2000 meshes, and the silicon micro powder is used as a wear-resistant filler, so that the cost can be reduced.

The heavy-duty anticorrosive powder coating provided by the invention comprises 0.5-1.5% of dispersing agent, which can be 0.5%, 1% or 1.5% by mass. In the invention, the dispersing agent is preferably SA516 dispersing agent (Liuan Jiegun to New materials Co., ltd.) which can make powder easier to disperse stably and quickly.

The heavy-duty anticorrosive powder coating provided by the invention comprises 0.5-1.5% of wetting agent, which can be 0.5%, 1%, 1.2% or 1.5% by mass. In the present invention, the wetting agent is preferably 701 wetting agent (Huang Shanjin, inc.), which helps to wet the powder during the coating process and to better distribute the dispersant over the powder surface.

The heavy-duty anticorrosive powder coating provided by the invention comprises 0.5-1.5% of defoamer, which can be 0.5%, 1% or 1.5% by mass. In the embodiment of the invention, the defoaming agent is preferably 542DG defoaming agent (Trojan Troy), and is used for releasing gas when the coating is cured, so that bubbles in the coating are not easy to generate.

The heavy-duty anticorrosive powder coating provided by the invention comprises 0.4-1.5% of conductive agent, which can be 0.4%, 0.5%, 1% or 1.5% by mass. In the invention, the conductive agent is preferably conductive mica powder with the particle size of 5-20 microns, and is used for improving the conductivity of the coating during electrostatic spraying so as to enable the coating to be sprayed on a workpiece better.

The heavy-duty anticorrosive powder coating provided by the invention comprises 0.5-1.5% of adhesion promoter, which can be 0.5%, 1% or 1.5% by mass. In the present invention, the adhesion promoter is preferably BYK-3942P (Pick).

The heavy-duty anticorrosive powder coating provided by the invention comprises 0.5-1.5% of flatting agent, which can be 0.5%, 1%, 1.2% or 1.5% by mass. In the invention, the leveling agent is preferably PL-200 leveling agent (Estren), which can reduce the surface tension of the coating during baking, solidifying and melting, improve the leveling property of the coating and is not easy to generate uneven orange peel.

The preparation raw materials of the heavy-duty anticorrosive powder coating provided by the invention comprise 1-5% of dicyandiamide curing agent, and the dicyandiamide curing agent can be 2%, 3%, 4% or 5%. In the present invention, the dicyandiamide-based curing agent is preferably K7104 (hexa-ambda to new materials limited, modified dicyandiamide). In the present invention, the dicyandiamide-based curing agent is crosslinked with the resin to finally cure the coating into the coating.

In the invention, the particle size of the heavy-duty powder coating is preferably less than 70 microns, and the mass ratio of the particles with the particle size less than 50 microns is more than or equal to 80%.

The heavy-duty powder coating provided by the invention is a wear-resistant and corrosion-resistant integrated coating with excellent interface bonding performance, and can realize long-term protection (high-pressure and high-temperature test at 70MPa/180 ℃ for more than or equal to 16 h) of the coating under extreme working conditions. The traditional epoxy powder coating is easy to generate bubbling-stripping failure under the high pressure of 70MPa and the high temperature of 148 ℃, and the abrasion resistance is insufficient, so that the abrasion of the inner wall of a pipeline is serious (the abrasion resistance of a shakeout method is less than or equal to 2.0L/mu m), and the bonding strength of the coating and a matrix interface is low (the adhesive force is less than or equal to 5A grade).

The invention provides a preparation method of the heavy-duty anticorrosive powder coating, which comprises the following steps:

Premixing graphene modified silicon-titanium nano polymer slurry with a hydrophobic interface modifier to form hydrophobized premix slurry;

mixing the hydrophobization premixed sizing agent with pigment and wear-resistant reinforcing filler to form core-shell structure sizing agent;

And mixing the core-shell structure slurry with epoxy resin, linear phenolic epoxy resin, modified organic silicon resin, mica powder, fumed silica, silicon micropowder, dispersing agent, wetting agent, defoamer, conductive agent, adhesion promoter, leveling agent and dicyandiamide curing agent, and carrying out melt extrusion on the obtained mixture to obtain powder, thereby obtaining the heavy-duty anticorrosive powder coating.

According to the preparation method, graphene modified silicon-titanium nano polymer slurry and a hydrophobic interface modifier are premixed to form hydrophobization premixed slurry. In the invention, a coupling agent (such as an epoxy silane coupling agent) in the graphene modified silicon titanium nano polymer slurry can be subjected to silanol condensation with a hydrophobic interface modifier (a fluorocarbon silane coupling agent and/or a modified polysiloxane copolymer), and the graphene modified silicon titanium nano polymer slurry contains solid particulate matters (silicon dioxide and titanium hydride), so that the hydrophobic interface modifier can migrate to the surface of solid particles to be coupled and coated with the solid particulate matters and can also be subjected to condensation with the silane coupling agent on the surface of the solid particles, so that the hydrophobic interface modifier cannot migrate and is anchored around the solid particles of the slurry, and a hydrophobic coating layer can be formed through premixing. In the invention, the water contact angle of the hydrophobization premix slurry and the surface of the coating cured by the amine curing agent for the epoxy resin is more than or equal to 110 degrees.

After the hydrophobization premix slurry is obtained, the hydrophobization premix slurry is mixed with wear-resistant reinforcing filler to form core-shell structure slurry. In the present invention, the mixing is preferably performed in a high-speed disperser, and the rotation speed is preferably 5000 to 8000rpm, may be 5000, 6000, 7000 or 8000rpm, and the mixing time is preferably 15 to 20min, may be 15, 17 or 20min. Because the graphene modified silicon-titanium nano polymer slurry contains resin (silicon modified epoxy resin) and a large amount of coupling agents, the resin is adsorbed and anchored on the surface of the solid wear-resistant reinforced filler, and a core-shell structure can be formed through the mixing.

After the core-shell structure slurry is obtained, the core-shell structure slurry is mixed with epoxy resin, linear phenolic epoxy resin, modified organic silicon resin, pigment, mica powder, fumed silica, silica micropowder, dispersing agent, wetting agent, defoamer, conductive agent, adhesion promoter, leveling agent and dicyandiamide curing agent, and the obtained mixture is subjected to melt extrusion and then is prepared into powder, so that the heavy-duty anticorrosive powder coating is obtained.

In the present invention, the mixing is preferably high-speed dispersion mixing, and the rotation speed of the high-speed dispersion mixing is preferably 1000 to 2000rpm, which may be 1000, 15000 or 2000rpm, and the time is preferably 20 to 60min, which may be 20, 30, 40, 50 or 60min.

In the invention, the melt extrusion is preferably twin-screw extrusion, and is specifically performed in a twin-screw extruder, and from a feed end, the twin-screw extruder is sequentially provided with a zone I, a zone II and a zone III, wherein the temperature of the zone I is preferably 95-110 ℃, can be 95, 100, 105 or 110 ℃, the temperature of the zone II is preferably 110-130 ℃, can be 110, 120 or 130 ℃, and the temperature of the zone III is preferably 90-100 ℃, can be 90, 95 or 100 ℃.

In the invention, the method for preparing the powder is preferably to cut and crush the material slices after the melt extrusion and then sift the material slices, and the sifting is preferably to sift the material slices through a 200-mesh sieve.

The invention provides the application of the heavy-duty powder coating prepared by the technical scheme or the preparation method of the technical scheme in oilfield pipeline corrosion prevention.

The heavy-duty powder coating provided by the invention is especially suitable for long-acting protection of oilfield pipelines under the working conditions of high temperature, high pressure and strong corrosion, and passes the authoritative detection certification of the national petroleum pipe quality inspection and detection center (CNPC).

In the present invention, the method of application is preferably:

preheating an oilfield pipeline after pretreatment;

Spraying the heavy anti-corrosion powder coating on the preheated oilfield pipeline, and then curing.

In the invention, the pretreatment is specifically to sand blast and rust remove the oilfield pipeline to Sa 2.5-3 grade (the grain size of steel grit is 0.8-1.2 mm), and the surface roughness Ra of the oilfield pipeline after pretreatment is preferably 35-75 mu m. In the invention, the preheating temperature is preferably 180-220 ℃. In the invention, the parameters of spraying are preferably spraying thickness of 0.35+/-0.05 mm, rotating speed of 200-250 rpm, moving speed of a spray gun of 20-30 m/min, curing parameters are preferably temperature of 200-240 ℃, time of more than or equal to 30min, and rotary curing (sagging prevention).

In order to further illustrate the present invention, the following examples are provided to describe in detail the preparation method of the modified silicone resin and the heavy duty powder coating material, as well as the preparation method and application thereof, but they should not be construed as limiting the scope of the present invention.

Example 1

The heavy-duty anticorrosive powder coating comprises the following preparation raw materials in parts by weight as shown in table 1.

Table 1 raw materials for preparing heavy-duty anticorrosive powder coating and parts by weight of each raw material

The preparation steps of the modified silicone resins in table 1 are as follows:

(1) Hydrolysis reaction, namely adding 70g of methyltrimethoxysilane (MTMS), 30g of Phenyltriethoxysilane (PTES) and 20g of isocyanatopropyl triethoxysilane into a reaction kettle filled with 100mL of ethanol-water (the volume ratio of ethanol to water is 95:5) with pH=4.5, and stirring and reacting for 2h at 60 ℃;

(2) Polycondensation modification, namely adding 15g of dicyandiamide and 8g of NH ₂ -POSS (purchased from Siam Azithro Yue Shengwu) into the product of the step (1), heating to 80 ℃ for reaction for 3 hours, wherein the viscosity of the system reaches 2500 mPa.s;

(3) And (3) solid powdering treatment, namely, vacuum desolventizing at 120 ℃ and crushing to obtain modified organic silicon resin powder.

The preparation method of the heavy-duty anticorrosive powder coating comprises the following steps:

(1) Primary dispersion, namely premixing graphene modified silicon-titanium nano polymer slurry and a hydrophobic interface modifier to form hydrophobized premix slurry (the contact angle is more than or equal to 110 °);

(2) Secondary dispersion, namely treating the premixed slurry obtained in the step (1) and filler (ceramic alumina and silicon carbide) in a high-speed dispersing machine (6000 rpm) for 20min to form core-shell structure slurry;

(3) And (3) three-stage dispersion, namely adding the rest components into the material obtained in the step (2), adopting high-speed mixing and dispersing (with the rotating speed of 2000rpm and the treatment time of 40 min), and then carrying out sectional temperature control (the 105 ℃ in the zone I/the 120 ℃ in the zone II/the 100 ℃ in the zone III) of the twin-screw extruder, carrying out melt extrusion slicing crushing, sieving with a 200-mesh sieve, wherein the particle size of the powder coating is less than 70 microns, and the mass ratio of particles with the particle size of less than 50 microns is more than or equal to 80%.

Comparative example 1

The digao 450 in table 1 is omitted and the rest is the same as table 1. The preparation steps of the heavy duty powder coating are as follows (i.e. comparative example 1 is not subjected to hydrophobic functional surface modification):

The graphene modified silicon-titanium nano polymer slurry, the filler (ceramic alumina and silicon carbide) and other residual components are mixed and dispersed at high speed (the rotating speed is 2000rpm, the processing time is 40 min), and then the mixture is subjected to sectional temperature control (105 ℃ in a zone I/120 ℃ in a zone II/100 ℃ in a zone III) of a double-screw extruder, melt extrusion, slicing and crushing, sieving through a 200-mesh sieve, wherein the particle size of the powder coating is less than 70 microns, and the mass ratio of the particles with the particle size less than 50 microns is more than or equal to 80%.

The heavy duty powder coating prepared in example 1 was tested for performance (as measured by CNPC, under standard SY/T6717-2016) and the test results were as follows:

The appearance is flat, uniform and smooth, and has no defects of bubbles, orange peel, drool and the like;

The dry film thickness is 277.5 mu m;

a leakage point is not found;

abrasion resistance 2.2L/. Mu.m (shakeout method);

Adhesion force 5 class a (class 3A better than standard requirements);

Resistance to corrosion by chemical media:

10% HCl (room temperature, 90 days) with no change in the coating,

3.5% NaCl (room temperature, 90 days) the coating was unchanged,

Crude oil (80 ℃ for 90 days) with no change in coating;

High temperature and high pressure performance:

The test piece is completely put into liquid under the conditions that the liquid phase is NaOH solution (pH=12.5) and H ₂SO₄ solution (pH=2) are respectively carried out at 180 ℃ per 70MPa per 16H, gas N ₂ is used for pressurizing, the test piece is 2 in the conditions that the liquid phase is mixed liquid of water, toluene and kerosene in equal volume ratio, the temperature is 107 ℃ per 35MPa per 16H, the test piece is 2/3 immersed in the liquid, CO ₂ is used for pressurizing, and the three test results under the two conditions are that the coating has no bubbles and the adhesive force is kept at 5A level.

The wear resistance is improved by more than or equal to 26.7 percent (the standard is required to be 2.0L/mum), the adhesive force is improved by more than or equal to 66.7 percent (the standard is required to be 3A grade), and the 16h extreme working condition test (180 ℃ C./70 MPa) is passed.

FIG. 1 is an electron microscope image (a) of a commercially available ordinary sintered epoxy powder coating after abrasion resistance test and an electron microscope image (b) of a heavy duty powder coating obtained in comparative example 1 after abrasion resistance test. Fig. 2 is an electron microscope image (a) of a commercially available common sintered epoxy powder coating after abrasion resistance test and an electron microscope image (b) of a heavy anti-corrosion powder coating obtained by multistage dispersion in example 1 after abrasion resistance test. The conventional sintered epoxy powder coating of fig. 2 was purchased from a different manufacturer than the conventional sintered epoxy powder coating of fig. 1. As can be seen in FIG. 1, (a) in FIG. 1 is much larger in particle size than the coating interior pigment in FIG. 1, (b) in FIG. 1, and (a) in FIG. 1 is much less dense than (b) in FIG. 1, and the grinding marks are also more pronounced. In fig. 2, (a) is significantly larger and more porous than (b) in the coating, the abrasion mark is significant, and even if (b) in fig. 2 is observed twice as much as (a) in fig. 1 and 2, the agglomerated solid particles are hardly seen inside the coating, and the abrasion mark is minimal.

Fig. 3 shows the appearance of the heavy-duty powder coating obtained by multistage dispersion in example 1, and it can be seen that the coating surface is smooth, uniform and fine.

The heavy duty powder coating prepared in example 1 was subjected to high temperature high pressure compression testing (see SY/T6717-2016) and compared to conventional sintered epoxy coatings, and the test conditions and results are shown in Table 2.

TABLE 2 high temperature high pressure analog test results

Example 2

The heavy duty powder coating was prepared from the raw materials shown in Table 3 in parts by weight, and the remainder was the same as in example 1.

Table 3 raw materials for preparing heavy-duty anticorrosive powder coating and parts by weight of the raw materials

Example 3

The weight percent of the raw materials and the mass parts of the heavy-duty powder coating are shown in Table 4, and the rest is the same as in example 1.

Table 4 raw materials for preparing heavy-duty anticorrosive powder coating and parts by weight of the raw materials

The results of the performance test of the heavy duty powder coatings prepared in examples 2-3 are shown in Table 5.

Table 5 Performance test results of heavy duty powder coatings prepared in examples 2 to 3

From the above embodiments, it can be seen that the heavy-duty powder coating provided by the invention is a wear-resistant and corrosion-resistant integrated coating with excellent interface bonding performance, and can realize long-term protection of the coating under extreme working conditions.

The foregoing is merely a preferred embodiment of the present invention and is not intended to limit the present invention in any way. It should be noted that modifications and adaptations to the present invention may occur to one skilled in the art without departing from the principles of the present invention and are intended to be comprehended within the scope of the present invention.

Claims (10)

1. The preparation method of the modified organic silicon resin is characterized by comprising the following steps of:

Mixing methyltrimethoxysilane, phenyltriethoxysilane and isocyanatopropyl triethoxysilane with an alcohol-water solvent for hydrolytic polycondensation to obtain a solution containing terminal isocyanate polysiloxane, wherein the hydrolytic polycondensation is carried out under the condition that the pH value is 3-6;

Mixing the solution containing isocyanate groups with dicyandiamide and amino cage-type silsesquioxane to carry out hybridization crosslinking polycondensation reaction to obtain a solution containing Si, O, C and N hybridization crosslinking polymers;

And removing the solvent from the solution containing the Si, O, C and N hybrid cross-linked polymer to obtain the modified organic silicon resin.

2. The preparation method of claim 1, wherein the methyltrimethoxysilane is 60-80 parts by mass, the phenyltriethoxysilane is 20-40 parts by mass, the isocyanatopropyl triethoxysilane is 15-25 parts by mass, the dicyandiamide is 10-20 parts by mass, and the aminated cage-type silsesquioxane is 5-10 parts by mass.

3. The preparation method according to claim 1 or 2, wherein the temperature of the hydrolytic polycondensation is 50-80 ℃ for 2-4 hours, and the temperature of the hybridization cross-linking polycondensation reaction is 60-100 ℃ for 2-6 hours.

4. The heavy-duty anticorrosive powder coating is characterized by comprising the following preparation raw materials in percentage by mass:

15-35% of epoxy resin, 5-15% of linear phenolic epoxy resin, 15-25% of modified organic silicon resin, 2-5% of graphene modified silicon titanium nano polymer slurry, 15-25% of wear-resistant reinforcing filler, 1-10% of mica powder, 0.5-2% of pigment, 0.1-0.3% of hydrophobic interface modifier, 0.1-1% of fumed silica, 5-15% of silica micropowder, 0.5-1.5% of dispersing agent, 0.5-1.5% of wetting agent, 0.5-1.5% of defoaming agent, 0.4-1.5% of conductive agent, 0.5-1.5% of adhesion promoter, 0.5-1.5% of leveling agent and 1-5% of dicyandiamide curing agent;

The wear-resistant reinforcing filler comprises carbide and/or metal oxide, the hydrophobic interface modifier comprises fluorocarbon silane coupling agent and/or modified polysiloxane copolymer, and the modified organic silicon resin is prepared by the preparation method according to any one of claims 1-3;

the graphene modified silicon titanium nano polymer slurry comprises, by mass, 40-60 parts of titanium hydride, 2-5 parts of active silicon dioxide, 1-2 parts of silane coupling agent modified graphene, 10-30 parts of silicon modified epoxy resin, 3-6 parts of active diluent, 2-10 parts of N-methylpyrrolidone, 1-5 parts of dispersing agent, 1-5 parts of coupling agent, 0.01-0.1 part of catalyst, 0.1-0.2 part of wetting agent and 0.1-0.2 part of wetting auxiliary agent.

5. The heavy duty powder coating of claim 4, wherein the epoxy resin has an epoxy equivalent of 600 to 1800.

6. The heavy duty powder coating of claim 4, wherein the carbide comprises one or more of silicon carbide, titanium carbide, and tungsten carbide, and the metal oxide comprises zirconia and/or ceramic alumina.

7. The heavy duty powder coating of claim 4, wherein the fluorocarbon silane coupling agent comprises heptadecafluorodecyltriethoxysilane and the modified polysiloxane copolymer comprises polyether siloxane.

8. The heavy-duty powder coating according to any one of claims 4 to 7, wherein the heavy-duty powder coating has a particle size of less than 70 microns and a particle mass ratio of less than 50 microns of not less than 80%.

9. The method for preparing the heavy-duty powder coating according to any one of claims 4 to 8, which is characterized by comprising the following steps:

Premixing graphene modified silicon-titanium nano polymer slurry with a hydrophobic interface modifier to form hydrophobized premix slurry;

Mixing the hydrophobization premixed slurry with wear-resistant reinforcing filler to form core-shell structure slurry;

and mixing the core-shell structure slurry with epoxy resin, linear phenolic epoxy resin, modified organic silicon resin, pigment, mica powder, fumed silica, silicon micropowder, dispersing agent, wetting agent, defoamer, conductive agent, adhesion promoter, leveling agent and dicyandiamide curing agent, and carrying out melt extrusion on the obtained mixture to obtain powder, thereby obtaining the heavy-duty anticorrosive powder coating.

10. The heavy-duty powder coating as claimed in any one of claims 4 to 8 or the heavy-duty powder coating prepared by the preparation method as claimed in claim 9, and the application thereof in oilfield pipeline corrosion prevention.