Temperature-resistant anticorrosive paint for pipelines and preparation method thereof

Abstract

The preparation method comprises the following steps: uniformly mixing a mixed epoxy resin, an auxiliary agent and a mixed solvent in proportion, adding titanium dioxide, talcum powder and precipitated barium sulphate, uniformly dispersing, adding a heat-resistant filler, and uniformly stirring to obtain a component A; uniformly mixing the modified hyperbranched amino silicone curing agent and the mixed solvent in proportion to obtain a component B; and finally, uniformly mixing the component A and the component B to obtain the temperature-resistant anticorrosive paint for the pipeline. The coating prepared by the invention is high in solid content and environment-friendly, can be used for pipelines under a CUI insulating layer, has excellent temperature resistance and corrosion resistance, can also be used for outdoor pipelines, and has excellent weather resistance and durability.

Description

Technical Field

[0001] The invention belongs to the field of anti-corrosion coatings, and in particular relates to a heat-resistant anti-corrosion coating for pipelines and a preparation method thereof. Background Art

[0002] In the field of petrochemicals, pipelines are indispensable means of transportation. These pipelines are generally made of metal and will corrode during use. In particular, the high temperature on the surface of heated pipelines will damage the coating. The high temperature will also aggravate the corrosion of the pipeline by the corrosive medium. Moreover, most heated pipelines are covered with insulation materials, which leads to the accumulation of moisture and corrosive media in the annular gap between the insulation material and the metal surface and the defects on the metal surface, which in turn concentrates and enhances the corrosion. At the same time, the insulation material itself is water permeable. The corrosive pollutants (chlorides, silicates, etc.) inside and outside the material will dissolve with the entry of water. Ions accelerate the corrosion rate, leading to the occurrence of corrosion under the insulation layer. Therefore, using heat-resistant and anti-corrosion coatings to protect pipelines is one of the most economical and effective means.

[0003] Phenolic epoxy thermal insulation and anti-corrosion coatings used under the insulation layer have excellent adhesion and anti-corrosion properties, and are suitable for use as protective coatings on insulated pipes. They are widely used in the fields of petroleum, petrochemicals, offshore platforms, etc. However, there are certain defects in the use of epoxy thermal insulation coatings for pipes, which are as follows: (1) They can only be used for pipes below 200°C, and the temperature resistance range needs to be further improved; (2) Phenolic epoxy coatings have poor resistance to heat shock, and alternating hot and cold temperatures can easily cause the coating adhesion to decrease and the protective performance to deteriorate; (3) They have poor weather resistance, and coating on outdoor pipes can easily cause the coating to age and crack. Therefore, it is necessary to develop a high-solid content, environmentally friendly, heat-resistant and anti-corrosion coating for pipes that can be used for pipes under the CUI insulation layer, with excellent heat resistance and corrosion resistance, and can also be used for outdoor pipes, with excellent weather resistance and durability. Summary of the invention

[0004] The present invention is proposed to solve the problems existing in the prior art, and its purpose is to provide a heat-resistant and anti-corrosion coating for pipelines and a preparation method thereof.

[0005] The present invention is achieved through the following technical solutions:

[0006] A heat-resistant anticorrosive coating for a pipeline, the anticorrosive coating comprising a component A and a component B, wherein the mass ratio of the component A to the component B is (3-4):1;

[0007] The components included in the A component and the mass fractions of each component are as follows:

[0008]

[0009]

[0010] The sum of the weight parts of each component of the A component is 100 parts;

[0011] The components included in the B component and the mass fractions of each component are as follows:

[0012] 90-98 parts of modified hyperbranched amino silicone curing agent;

[0013] 2 to 10 parts of mixed solvent;

[0014] The total weight of each component of the B component is 100 parts.

[0015] In the above technical scheme, the mixed epoxy resin is a mixture of phenolic epoxy resin and bisphenol F epoxy resin; the mass ratio of the phenolic epoxy resin to the bisphenol F epoxy resin is (1-2):1; the phenolic epoxy resin is a phenolic epoxy resin with an epoxy value of 0.55-0.60; the bisphenol F epoxy resin is a bisphenol F epoxy resin with an epoxy value of 0.55-0.65.

[0016] In the above technical solution, the titanium dioxide is rutile titanium dioxide; the particle size of the talc is 400-500 mesh; the heat-resistant filler is basalt flakes; the particle size of the basalt flakes is 300-500 mesh.

[0017] In the above technical solution, the auxiliary agent is any one or more of a dispersant, a defoamer or a rheological auxiliary agent.

[0018] In the above technical solution, the dispersant is BYK-ATU; the defoamer is BYK-066 or AFCONA-2722; and the rheological additive is organic bentonite.

[0019] In the above technical solution, the mixed solvent is a mixture of xylene, butanol and propylene glycol methyl ether, and the mass ratio of xylene, butanol and propylene glycol methyl ether is (60-70):(10-20):(20-25).

[0020] In the above technical solution, the modified hyperbranched aminosilicone curing agent is obtained by reacting aminosiloxane, dipropylene glycol and anhydrous barium hydroxide.

[0021] In the above technical solution, the aminosiloxane is N-(2-aminoethyl)-3-aminopropylmethoxysilane and / or 3-aminopropyltriethoxysilane.

[0022] In the above technical scheme, the preparation method of the modified hyperbranched aminosilicone curing agent is specifically as follows: the aminosiloxane, dipropylene glycol and anhydrous barium hydroxide are mixed in a mass ratio of (50-55):(45-50):(0.5-1), nitrogen protection is maintained, the reaction is maintained at 80°C for 0.3h, and then the temperature is raised to 100°C for 3h, and the anhydrous barium hydroxide is removed to obtain a hyperbranched aminosilicone curing agent.

[0023] A method for preparing a heat-resistant and anti-corrosion coating for a pipeline comprises the following steps:

[0024] (I) adding the mixed epoxy resin, additives and mixed solvent into a reaction kettle in proportion and mixing, then adding titanium dioxide, talcum powder and precipitated barium sulfate, dispersing them evenly and grinding them to a fineness of less than 40 μm, then adding a heat-resistant filler and stirring for 30 to 50 minutes until uniform, to obtain component A;

[0025] (II) adding the modified hyperbranched amino silicone curing agent and the mixed solvent into a reaction kettle in proportion, stirring for 20 minutes until uniform, to obtain component B;

[0026] (III) Mix component A and component B evenly to obtain a heat-resistant and anti-corrosion coating for pipelines.

[0027] The beneficial effects of the present invention are:

[0028] The present invention provides a heat-resistant and anti-corrosion coating for pipelines and a preparation method thereof. The prepared coating has high solid content and is environmentally friendly. It can be used for pipelines under a CUI insulation layer and has excellent heat resistance and corrosion resistance, and can also be used for outdoor pipelines and has excellent weather resistance and durability. DETAILED DESCRIPTION

[0029] In order to enable those skilled in the art to better understand the technical solution of the present invention, the technical solution of the present invention is further described below in conjunction with the specification and through specific implementation methods.

[0030] Example 1

[0031] A heat-resistant and anti-corrosion coating for pipelines, wherein component A is made of the following components in parts by mass:

[0032] 25 parts of mixed epoxy resin (the mass ratio of novolac epoxy resin to bisphenol F epoxy resin is 1:1);

[0033] 10 parts of titanium dioxide

[0034] 10 parts of talcum powder;

[0035] 25 parts of precipitated barium sulfate;

[0036] 15 Basalt Scales

[0037] 3 parts of dispersant BYK-ATU

[0038] 1 part of defoamer BYK-066

[0039] 1 part organic bentonite

[0040] 10 parts of a mixed solvent (xylene, butanol and propylene glycol methyl ether in a mass ratio of 7:1:2);

[0041] The component B has the following components in parts by weight:

[0042] 98 parts of modified hyperbranched amino silicone curing agent

[0043] 2 parts of a mixed solvent (xylene, butanol and propylene glycol methyl ether in a mass ratio of 7:1:2).

[0044] The modified hyperbranched aminosilicone curing agent is prepared by a preparation method comprising the following steps: uniformly mixing N-(2-aminoethyl)-3-aminopropylmethoxysilane, dipropylene glycol and anhydrous barium hydroxide, protecting with nitrogen, maintaining a temperature of 80° C. for reaction for 0.3 h, then heating to 100° C. for reaction for 3 h, removing the anhydrous barium hydroxide, and preparing the hyperbranched aminosilicone curing agent, wherein the mass ratio of the N-(2-aminoethyl)-3-aminopropylmethoxysilane, dipropylene glycol and anhydrous barium hydroxide is 55:45:0.5.

[0045] The preparation method of the above-mentioned heat-resistant anti-corrosion coating for pipelines comprises the following steps:

[0046] (I) adding a mixed epoxy resin, a dispersant, a defoamer, and an organic bentonite mixed solvent into a reaction kettle and mixing evenly, adding titanium dioxide, talcum powder, and precipitated barium sulfate and dispersing evenly, grinding to a fineness of less than 40 μm, and then adding basalt flakes and stirring for 30 minutes until uniform, to obtain component A;

[0047] (II) adding the modified hyperbranched amino silicone curing agent and the mixed solvent into a reaction kettle and stirring for 20 minutes until uniform to obtain component B;

[0048] (III) Mix component A and component B evenly to obtain a heat-resistant and anti-corrosion coating for pipelines.

[0049] Example 2

[0050] A heat-resistant and anti-corrosion coating for pipelines, wherein the component A is made of the following components in parts by mass:

[0051] 25 parts of mixed epoxy resin (the mass ratio of novolac epoxy resin and bisphenol F epoxy resin is 2:1);

[0052] 15 parts of titanium dioxide

[0053] 20 parts of talcum powder;

[0054] 15 parts of precipitated barium sulfate;

[0055] 14 Basalt Scales

[0056] 3 parts of dispersant BYK-ATU

[0057] 8 parts of a mixed solvent (xylene, butanol and propylene glycol methyl ether in a mass ratio of 6:2:2);

[0058] The component B has the following components in parts by weight:

[0059] 95 parts of modified hyperbranched amino silicone curing agent

[0060] 5 parts of a mixed solvent (xylene, butanol and propylene glycol methyl ether in a mass ratio of 6:2:2).

[0061] The modified hyperbranched aminosilicone curing agent is prepared by a preparation method comprising the following steps: 3-aminopropyltriethoxysilane, dipropylene glycol and anhydrous barium hydroxide are mixed, nitrogen protection is performed, the reaction is maintained at 80°C for 0.3h, the temperature is then raised to 100°C for reaction for 3h, and the anhydrous barium hydroxide is removed to prepare the hyperbranched aminosilicone curing agent, wherein the mass ratio of the 3-aminopropyltriethoxysilane, dipropylene glycol and anhydrous barium hydroxide is 45:55:1.

[0062] The preparation method of the above-mentioned heat-resistant anti-corrosion coating for pipelines comprises the following steps:

[0063] (1) Add the mixed epoxy resin, dispersant and mixed solvent into a reaction kettle and mix well, add titanium dioxide, talcum powder and precipitated barium sulfate, disperse evenly and grind to a fineness of less than 40 μm, then add basalt flakes and stir for 50 minutes until uniform, to obtain component A;

[0064] (2) adding the modified hyperbranched amino silicone curing agent and the mixed solvent into a reaction kettle and stirring for 20 minutes until uniform to obtain component B;

[0065] (3) Mix component A and component B evenly to obtain a heat-resistant and anti-corrosion coating for pipelines.

[0066] Example 3

[0067] A heat-resistant and anti-corrosion coating for pipelines, wherein the component A is made of the following components in parts by mass:

[0068] 15 parts of mixed epoxy resin (the mass ratio of novolac epoxy resin to bisphenol F epoxy resin is 2:1);

[0069] 15 parts of titanium dioxide

[0070] 20 parts of talcum powder;

[0071] 25 parts of precipitated barium sulfate;

[0072] 5 pieces of basalt scales;

[0073] 3 parts of dispersant BYK-ATU;

[0074] 1 part of defoamer AFCONA-2722;

[0075] 1 part of organic bentonite;

[0076] 15 parts of a mixed solvent (xylene, butanol and propylene glycol methyl ether mass ratio 6:1.5:2.5);

[0077] The component B has the following components in parts by weight:

[0078] 90 parts of modified hyperbranched amino silicone curing agent

[0079] 10 parts of a mixed solvent (xylene, butanol and propylene glycol methyl ether in a mass ratio of 6:1.5:2.5).

[0080] The modified hyperbranched aminosilicone curing agent is prepared by a preparation method comprising the following steps: uniformly mixing N-(2-aminoethyl)-3-aminopropylmethoxysilane, dipropylene glycol and anhydrous barium hydroxide, protecting with nitrogen, maintaining a temperature of 80° C. for reaction for 0.3 h, then heating to 100° C. for reaction for 3 h, removing the anhydrous barium hydroxide, and preparing the hyperbranched aminosilicone curing agent, wherein the mass ratio of the N-(2-aminoethyl)-3-aminopropylmethoxysilane, dipropylene glycol and anhydrous barium hydroxide is 50:45:1.

[0081] The preparation method of the above-mentioned heat-resistant anti-corrosion coating for pipelines comprises the following steps:

[0082] (1) Add the mixed epoxy resin, dispersant, defoamer, organic bentonite and mixed solvent into a reaction kettle and mix well, add titanium dioxide, talcum powder and precipitated barium sulfate and grind to a fineness of less than 40 μm after being dispersed evenly, then add basalt flakes and stir for 40 minutes until uniform, to obtain component A;

[0083] (2) adding the modified hyperbranched amino silicone curing agent and the mixed solvent into a reaction kettle and stirring for 20 minutes until uniform to obtain component B;

[0084] (3) Mix component A and component B evenly to obtain a heat-resistant and anti-corrosion coating for pipelines.

[0085] The high temperature resistant anticorrosive coatings for pipelines prepared in Examples 1 to 3 were tested for adhesion, temperature change resistance, temperature cycle resistance, salt spray resistance and aging resistance. A 150mm×75mm×3mm steel plate was used for the test, and the film thickness was about 250μm. The coating was tested for adhesion by the pull-off method according to GB / T 5210-2006; the coating was tested for heat cycle resistance according to GB / T 1735-2009 and GB / T1766-2008, and the test stipulated that the temperature was raised to 300°C, kept warm for 6 hours, and naturally cooled to room temperature in an oven as one cycle; the coating was tested for temperature change resistance according to JG / T 25-2017, and the test stipulated that the temperature was raised to 300°C, kept warm for 2 hours-0°C water cooling-room temperature placement as one cycle; the neutral salt spray test was carried out according to ASTM B117; and the UV aging resistance test was carried out according to GB / T1865-2009. Comparative Example The commercially available phenolic epoxy paint MC-NE-4 was selected for comparison. The test results of Examples 1 to 3 and the comparative example are shown in Table 1.

[0086] Table 1 Paint film performance test results

[0087]

[0088] As can be seen from Table 1, the heat-resistant anticorrosive coating for pipelines prepared in Examples 1 to 3 uses a mixture of bisphenol F epoxy resin and phenolic epoxy resin as the main film-forming material, which can reduce the brittleness of the paint film due to the high functionality and high rigidity of the phenolic epoxy resin, and improve the flexibility of the paint film. At the same time, the amino group is connected to the silicone resin through a silicon-carbon bond, which catalyzes the condensation of siloxane to form a hyperbranched branch chain. Most of the reactive sites in the hyperbranched structure are located in the branched structure, which reduces the internal stress of the epoxy system and further plays a toughening effect. Therefore, the heat cycle resistance and temperature change resistance of Examples 1 to 3 are better than those of the comparative example. Due to the introduction of the hyperbranched structure, there are many reactive sites, the coating is more compact, the cross-linking density is greater, and the anti-corrosion performance is greatly improved. At the same time, the basalt flakes can be distributed in parallel in the coating in the paint film, prolonging the time for the corrosive medium to reach the substrate, filling the pores in the resin coating, and enhancing the shielding property of the coating. Therefore, the adhesion and salt spray resistance of Examples 1-3 are significantly better than those of the control example. The modified hyperbranched amino silicone introduced as a curing agent introduces a stable Si-O bond, which can resist ultraviolet radiation and oxidative corrosion, maintain stable weather resistance and durability, so that Examples 1-3 have excellent ultraviolet aging resistance. In addition, the heat-resistant anticorrosive coating for pipelines of the present invention is a high-solid coating that can be constructed with a high film thickness and is green and environmentally friendly.

[0089] Principle of the present invention:

[0090] The present invention uses a mixture of bisphenol F epoxy resin and novolac epoxy resin as the main film-forming material, which has the following main effects: (1) bisphenol F epoxy resin has excellent thermal stability and good corrosion resistance, and has relatively low viscosity, which can increase the solid content of the heat-resistant and anti-corrosion coating, reduce the solvent usage of the entire coating, and is green and environmentally friendly; (2) the mixture of bisphenol F epoxy resin and novolac epoxy resin can reduce the brittleness of the paint film caused by the high functionality and rigidity of the novolac epoxy resin, improve the flexibility of the paint film, and enhance the coating's resistance to temperature changes.

[0091] The present invention uses a modified hyperbranched aminosilicone curing agent, and the main benefits are as follows: after curing with the mixed epoxy resin, the amino group is connected to the silicone resin through a silicon-carbon bond, which not only catalyzes the condensation of siloxane to form a hyperbranched branch chain, but also can serve as a curing reaction group at room temperature. The hyperbranched branch chain has many active sites and large functionality, so the coating is more compact, has excellent corrosion resistance and fast drying time; most of the reactive sites in the hyperbranched structure are located in the branched structure, which reduces the internal stress of the epoxy system and has a toughening effect; the Si-O bond formed by covalent bonding in the modified hyperbranched aminosilicone has sufficient stability, can resist ultraviolet radiation and oxidative corrosion, so that the coating can remain stable for a long time in an outdoor environment, and improve the weather resistance of the coating.

[0092] The resin system constructed in the present invention uses modified hyperbranched amino silicone as a curing agent, and the beneficial effects produced are unexpected. First, the viscosity of the mixed epoxy resin is effectively low, and the prepared heat-resistant and anti-corrosion coating is a green high-solid coating. Secondly, it is coated on the insulation pipe. Because the mixed epoxy resin has excellent corrosion resistance and flexibility, the silicone introduced in the epoxy system forms a siloxane condensation structure, which enhances the bond energy of the resin molecules in the coating. The heat resistance of the coating reaches 300°C, which is far higher than that of traditional phenolic epoxy coatings. Thirdly, the presence of silane bonds greatly enhances the stability of the coating, and it has excellent weather resistance and durability when used on outdoor pipes.

[0093] The present invention selects basalt flakes as temperature-resistant fillers. Basalt flakes are green and environmentally friendly flaky materials with high thermal stability. They can be distributed in parallel in the coating in the paint film, prolonging the time for the corrosive medium to reach the substrate. They can also fill the pores in the resin coating and enhance the shielding properties of the coating, effectively improving the corrosion resistance of the coating. At the same time, the flaky structure is dispersed in the coating, which can effectively reduce the curing internal stress under high film thickness and improve the resistance to cracking during hot and cold shock.

[0094] The applicant declares that the above is only a specific implementation mode of the present invention, but the protection scope of the present invention is not limited thereto. Those skilled in the art should understand that any changes or substitutions that can be easily thought of by those skilled in the art within the technical scope disclosed by the present invention shall fall within the protection scope and disclosure scope of the present invention.

Claims

1. A heat-resistant and anti-corrosion coating for pipelines, characterized in that: The anticorrosive coating comprises component A and component B, wherein the mass ratio of component A to component B is (3-4):1; The components included in the A component and the mass fractions of each component are as follows: The sum of the weight parts of each component of the A component is 100 parts; The components included in the B component and the mass fractions of each component are as follows: 90-98 parts of modified hyperbranched amino silicone curing agent; 2 to 10 parts of mixed solvent; The total weight of each component of the B component is 100 parts.

2. The heat-resistant and anti-corrosion coating for pipelines according to claim 1, characterized in that: The mixed epoxy resin is a mixture of phenolic epoxy resin and bisphenol F epoxy resin; the mass ratio of the phenolic epoxy resin to the bisphenol F epoxy resin is (1-2):1; the phenolic epoxy resin is a phenolic epoxy resin with an epoxy value of 0.55-0.60; the bisphenol F epoxy resin is a bisphenol F epoxy resin with an epoxy value of 0.55-0.

65.

3. The heat-resistant and anti-corrosion coating for pipelines according to claim 1, characterized in that: The titanium dioxide is rutile titanium dioxide; the particle size of the talc is 400-500 mesh; the heat-resistant filler is basalt flakes; the particle size of the basalt flakes is 300-500 mesh.

4. The heat-resistant and anti-corrosion coating for pipelines according to claim 1, characterized in that: The auxiliary agent is any one or more of a dispersant, a defoamer or a rheological auxiliary agent.

5. The heat-resistant and anti-corrosion coating for pipelines according to claim 4, characterized in that: The dispersant is BYK-ATU; the defoamer is BYK-066 or AFCONA-2722; and the rheological additive is organic bentonite.

6. The heat-resistant and anti-corrosion coating for pipelines according to claim 1, characterized in that: The mixed solvent is a mixture of xylene, butanol and propylene glycol methyl ether, and the mass ratio of the xylene, butanol and propylene glycol methyl ether is (60-70): (10-20): (20-25).

7. The heat-resistant and anti-corrosion coating for pipelines according to claim 1, characterized in that: The modified hyperbranched aminosilicone curing agent is obtained by reacting aminosiloxane, dipropylene glycol and anhydrous barium hydroxide.

8. The heat-resistant and anti-corrosion coating for pipelines according to claim 7, characterized in that: The aminosiloxane is N-(2-aminoethyl)-3-aminopropylmethoxysilane and / or 3-aminopropyltriethoxysilane.

9. The heat-resistant and anti-corrosion coating for pipelines according to claim 1, characterized in that: The preparation method of the modified hyperbranched aminosilicone curing agent is specifically as follows: the aminosiloxane, dipropylene glycol and anhydrous barium hydroxide are mixed in a mass ratio of (50-55):(45-50):(0.5-1), nitrogen protection is applied, the temperature is maintained at 80° C. for reaction for 0.3 h, the temperature is then raised to 100° C. for reaction for 3 h, and the anhydrous barium hydroxide is removed to obtain the hyperbranched aminosilicone curing agent.

10. A method for preparing the heat-resistant and anti-corrosion coating for pipelines according to any one of claims 1 to 9, characterized in that: The following steps are involved: (I) mixing the mixed epoxy resin, the additive and the mixed solvent in proportion, adding titanium dioxide, talcum powder and precipitated barium sulfate thereto and dispersing them evenly, and then adding the heat-resistant filler and stirring evenly to obtain component A; (II) mixing the modified hyperbranched amino silicone curing agent and the mixed solvent in proportion to obtain component B; (III) Mix component A and component B evenly to obtain a heat-resistant and anti-corrosion coating for pipelines.

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