A phenolic epoxy anticorrosive coating and its preparation method and application

Abstract

The invention discloses a phenolic epoxy anticorrosive coating and a preparation method and application thereof, and belongs to the technical field of anticorrosive coating. The anticorrosive coating comprises component A and component B, wherein component A comprises phenolic epoxy resin, wetting dispersant, adhesion promoter, thixotropic agent, pigment, filler, solvent A, and component B comprises Mannich base curing agent and solvent B; wherein the phenolic epoxy resin is composed of phenolic epoxy resin and bisphenol A epoxy resin, the wetting dispersant is composed of copolymer containing acidic group and modified polyurethane, the adhesion promoter is composed of titanate and aromatic polyether polyol, the thixotropic agent is composed of organic bentonite and polyamide wax slurry, the pigment is composed of color pigment and zinc phosphate antirust pigment, and the filler is composed of hydrophobic filler and precipitated barium sulfate. The anticorrosive coating of the invention has excellent resistance to moisture and heat, corrosion resistance, temperature change cycle resistance, flexibility and adhesion, and can provide long-term protection for the metal substrate under the insulation layer.

Description

Technical Field

[0001] The invention relates to the technical field of anti-corrosion coatings, and in particular to a phenolic epoxy anti-corrosion coating and a preparation method and application thereof. Background Art

[0002] Corrosion under insulation is a phenomenon in which the metal surface is exposed to a humid environment due to damage or penetration of the insulation layer, causing corrosion on the metal surface. In the petrochemical industry, corrosion under insulation is hidden and difficult to detect on a daily basis. Once the corrosion is serious, it will cause rupture, leakage or even explosion of pipelines or equipment, which is a major problem affecting long-term safe production.

[0003] Insulation materials are usually porous structures, and moisture in the external environment will penetrate into the insulation layer. During the operation of equipment or pipelines, temperature changes will also cause condensation water to form inside the insulation layer, forming a humid environment between the insulation layer and the metal substrate. In addition, impurity ions such as chloride ions and sulfate ions in the insulation material are dissolved in water, and pollutants such as sulfur dioxide and nitrogen oxides in the atmosphere penetrate and react chemically in the insulation material, forming a highly corrosive solution environment between the insulation layer and the metal substrate, posing a serious corrosion threat to metal parts. At the same time, corrosive solutions accumulate on the surface of equipment or pipelines. As the amount of solution entering the insulation layer continues to increase and the solution circulates, dissolves and evaporates, the concentration of the corrosive medium continues to increase, thereby accelerating the occurrence of corrosion under the insulation layer.

[0004] Due to the high temperature and high humidity corrosion environment under the insulation layer, even the inorganic zinc-rich primer, which is considered to have excellent anti-corrosion performance, faces huge challenges and is difficult to undertake the task of effective anti-corrosion. The existing technology for the research of coatings under the insulation layer is mainly committed to improving its temperature resistance and corrosion resistance. For example, Chinese patent application CN117247734A discloses an anti-corrosion solvent-free modified silicone coating under the insulation layer and its preparation method, CN114933838A discloses an epoxy silicone modified phenolic epoxy heat-resistant anti-corrosion coating and its preparation method, and CN113667377A discloses an anti-corrosion coating under the insulation layer and its application, coating process, and anti-corrosion coating. Although the temperature resistance and corrosion resistance of the anti-corrosion coatings prepared by these methods are improved, the adhesion is low, especially the adhesion is significantly reduced after the temperature change test, and the effect of long-term protection cannot be achieved.

[0005] Therefore, there is an urgent need to develop a coating that can enhance heat resistance and corrosion resistance as well as improve flexibility and adhesion, so as to permanently prevent corrosion of the metal substrate and ensure the long-term safe operation of equipment or pipelines. Summary of the invention

[0006] In order to solve the above technical problems, the present invention provides a phenolic epoxy anti-corrosion coating and a preparation method and application thereof. The phenolic epoxy anti-corrosion coating has excellent moisture and heat resistance, corrosion resistance, temperature change cycle resistance, flexibility and adhesion, and can provide long-term protection for the metal substrate under the insulation layer.

[0007] The technical solution adopted by the present invention is:

[0008] In a first aspect, the present invention provides a phenolic epoxy anticorrosive coating, comprising a component A and a component B;

[0009] Component A includes the following ingredients in parts by weight:

[0010] 30-45 parts of phenolic epoxy resin;

[0011] Wetting and dispersing agent 0.1~3 parts;

[0012] Adhesion promoter 0.5~2 parts;

[0013] Thixotropic agent 0.5~3 parts;

[0014] Pigment 15~30 parts;

[0015] 15~30 parts of filler;

[0016] Solvent A 10-15 parts;

[0017] The novolac epoxy resin is composed of phenol-type novolac epoxy resin and bisphenol A-type novolac epoxy resin;

[0018] Component B includes the following ingredients in parts by weight:

[0019] Mannich base curing agent 90-95 parts;

[0020] Solvent B 5-10 parts;

[0021] When in use, component A and component B are mixed in a mass ratio of 5 to 7:1.

[0022] Further, the amount of the phenol-type novolac epoxy resin added is 10 to 20 parts by weight, and the amount of the bisphenol A-type novolac epoxy resin added is 20 to 25 parts by weight;

[0023] The phenol-type novolac epoxy resin is at least one of NPPN-631, NPPN-638S, PNE177, and Kep1131;

[0024] The bisphenol A novolac epoxy resin is at least one of F-51 and BNE200.

[0025] Furthermore, the Mannich base curing agent is T33.

[0026] Furthermore, the wetting dispersant is composed of a copolymer dispersant containing an acidic group and a modified polyurethane dispersant, and the added amount of the copolymer dispersant containing an acidic group and the modified polyurethane dispersant is 0.05 to 1.5 parts by weight;

[0027] The adhesion promoter is composed of titanate and aromatic polyether polyol, and the addition amount of titanate is 0.3-1 parts by weight, and the addition amount of aromatic polyether polyol is 0.2-1 parts by weight;

[0028] The thixotropic agent is composed of organic bentonite and polyamide wax slurry, and the addition amount of the organic bentonite and the polyamide wax slurry is 0.25-1.5 parts by weight.

[0029] Further, the copolymer dispersant containing an acidic group is at least one of BYK-110, BYK-111, MOK-5611, and HY-9010;

[0030] The modified polyurethane dispersant is at least one of Efka4060, Efka PU 4063 and Efka PU 4061;

[0031] The titanate is at least one of isopropoxy tris (dioctyl pyrophosphate acyloxy) titanate, bis (dioctyl pyrophosphate acyloxy) ethylene titanate, isopropyl dioleyl acyloxy (dioctyl pyrophosphate acyloxy) titanate, and isopropyl tris (dioctyl pyrophosphate acyloxy) titanate;

[0032] The aromatic polyether polyol is at least one of bishydroxypropyl bisphenol fluorene ether and bishydroxyethyl bisphenol fluorene ether;

[0033] The organic bentonite is at least one of CARH-D10, BENTONE 38, HFGEL-40D, and HFGEL-127;

[0034] The polyamide wax slurry is at least one of HS SF-3620, LRH-467, and MT6900-20X.

[0035] Furthermore, the pigment is composed of a color pigment and a zinc phosphate antirust pigment, and the color pigment is added in an amount of 10 to 20 parts by weight, and the zinc phosphate antirust pigment is added in an amount of 5 to 15 parts by weight;

[0036] The filler consists of a hydrophobic filler and precipitated barium sulfate, wherein the amount of the hydrophobic filler added is 5 to 10 parts by weight, and the amount of the precipitated barium sulfate added is 10 to 20 parts by weight.

[0037] Furthermore, the color pigment is at least one of titanium dioxide, organic orange, phthalocyanine blue, carbon black, red iron oxide, and yellow iron oxide;

[0038] The hydrophobic filler is at least one of mica powder, nano silicon dioxide, polytetrafluoroethylene powder, organic silicon powder, graphite powder and glass flakes.

[0039] Furthermore, the solvent A and the solvent B are at least one of xylene, n-butanol, propylene glycol methyl ether, and propylene glycol methyl ether acetate.

[0040] In a second aspect, the present invention further provides a method for preparing a phenolic epoxy anticorrosive coating, comprising the steps of:

[0041] S1. Prepare component A: add phenolic epoxy resin, wetting dispersant, adhesion promoter, thixotropic agent, pigment and filler into a dispersion kettle according to the proportion, add a portion of solvent A, stir evenly, transfer to a grinder and grind to a fineness of ≤50 μm, then add another portion of solvent A to adjust the viscosity to 90-100 KU, and obtain component A after filtering;

[0042] S2, preparing component B: adding the Mannich base curing agent and solvent B into a batching tank in sequence according to the proportion, and stirring evenly to obtain component B;

[0043] S3. Evenly mix component A and component B in a mass ratio of 5 to 7:1 to obtain the phenolic epoxy anticorrosive coating.

[0044] In a third aspect, the present invention also provides an application of a phenolic epoxy anti-corrosion coating as an anti-corrosion coating on a metal substrate under an insulation layer.

[0045] The beneficial effects of the present invention are:

[0046] (1) The present invention provides a phenolic epoxy anticorrosive coating, which includes a phenolic epoxy resin, a wetting and dispersing agent, an adhesion promoter, a thixotropic agent, a pigment, a filler, a Mannich base curing agent and a solvent. The phenolic epoxy resin is compounded by a phenolic phenolic epoxy resin and a bisphenol A phenolic epoxy resin, and the curing agent is a Mannich base curing agent. After the phenolic phenolic epoxy resin and the bisphenol A phenolic epoxy resin are compounded, a cross-linking reaction occurs rapidly with active groups such as hydroxyl groups and amino groups in the molecular structure of the Mannich base curing agent, and at the same time, the molecular chain segments interact with each other to form a rigid skeleton. The complex network structure of the resin and the flexible chain segments enhances the flexibility, temperature resistance, chemical corrosion resistance and adhesion to the substrate of the coating. The cured coating has excellent water resistance and can effectively prevent water penetration. Even in a closed and humid environment, it can effectively avoid the problems of blistering, shedding and corrosion of the coating. In addition, the phenolic epoxy resin and the Mannich base curing agent can be quickly cured in low temperature or high temperature and high humidity environment. The effective curing broadens the adaptability to the spraying environment and has the characteristics of quick drying, which not only avoids the use of epoxy accelerators, but also improves production efficiency.

[0047] (2) The anticorrosive coating of the present invention uses titanate and aromatic polyether polyol as adhesion promoters, which not only improves the adhesion between the coating and the metal substrate through chemical bonding, but also enables the coating to maintain a high adhesion in a humid environment and after being subjected to temperature changes, thereby ensuring the integrity and protective effectiveness of the coating; in addition, the aromatic polyether polyol has a special structure and multi-functional groups, especially the introduction of dihydroxypropyl bisphenol fluorene ether or dihydroxyethyl bisphenol fluorene ether containing fluorene rings and hydroxyl groups, which enhances the cross-linking density of the coating, and the dense protective film formed prevents the penetration of moisture or chemical media, thereby improving the moisture and heat resistance, water resistance, flexibility, and chemical corrosion resistance of the coating, making the coating less likely to soften, deform, or lose adhesion in a high temperature environment, and able to resist corrosion by various acids, alkalis, salts and other chemical substances;

[0048] (3) The wetting and dispersing agent in the anti-corrosion coating of the present invention is composed of a copolymer containing an acidic group and a modified polyurethane. The compounded wetting and dispersing agent can effectively reduce the surface tension of the pigment and filler, promote their uniform dispersion in the coating system, improve the leveling property of the coating, and prevent the occurrence of floating color and blooming. The acidic groups in the copolymer dispersant containing an acidic group react chemically with the metal substrate to form a strong chemical bond. The addition of the modified polyurethane dispersant further enhances the cohesion of the coating and the bonding force with the substrate. The synergistic effect of the two improves the adhesion of the coating, making the coating more stable.

[0049] (4) The thixotropic agent in the anticorrosive coating of the present invention is composed of organic bentonite and polyamide wax slurry. The compounded thixotropic agent not only further enhances the thixotropy and dispersibility of the coating through synergistic effect, making the coating more uniform and stable during the construction process, improving the appearance of the paint film, but also shortens the drying time of the paint film, thereby improving the construction efficiency;

[0050] (5) The anti-corrosion coating of the present invention has excellent moisture and heat resistance, adhesion, flexibility and resistance to chemical media. It can not only withstand high temperatures and prevent metal corrosion, but also has good construction performance and environmental protection characteristics, and can be applied to complex industrial environments. DETAILED DESCRIPTION

[0051] The present invention provides a phenolic epoxy anticorrosive coating and a preparation method and application thereof. To make the purpose, technical solution and effect of the present invention clearer and more specific, the present invention is further described in detail below. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not intended to limit the present invention.

[0052] The invention provides a phenolic epoxy anticorrosive coating, comprising a component A and a component B, and when in use, the component A and the component B are mixed at a mass ratio of 5 to 7:1; the component A comprises: a phenolic epoxy resin, a wetting dispersant, an adhesion promoter, a thixotropic agent, a pigment, a filler, and a solvent A; the component B comprises: a curing agent and a solvent B.

[0053] Specifically, in the present invention, the novolac epoxy resin is composed of a phenol-type novolac epoxy resin and a bisphenol A novolac epoxy resin. In a preferred embodiment of the present invention, the phenol-type novolac epoxy resin has an epoxy equivalent of 165-210 g / mol, specifically at least one of NPPN-631, NPPN-638S, PNE177 or Kep1131, and the bisphenol A novolac epoxy resin is at least one of F-51 or BNE200.

[0054] Specifically, in the present invention, the curing agent is a Mannich base curing agent, and preferably, the Mannich base curing agent is T33.

[0055] In the present invention, after the above-mentioned phenol-type novolac epoxy resin is compounded with the bisphenol A novolac epoxy resin, a cross-linking reaction quickly occurs with the active groups such as hydroxyl groups and amino groups in the molecular structure of the Mannich base curing agent, and at the same time, the molecular segments interact with each other to form a complex network structure containing both a rigid skeleton and flexible segments, which can improve the flexibility, chemical corrosion resistance, and moisture and heat resistance of the coating; in addition, the bisphenol A novolac epoxy resin in the compounded novolac epoxy resin of the present invention has a bisphenol A skeleton, resulting in more side chains of the bisphenol A novolac epoxy resin than the phenol-type novolac epoxy resin, so that the cross-linking density of the compounded epoxy resin system is relatively larger than that of the phenol-type novolac epoxy resin, and the side chains of the bisphenol A novolac epoxy resin have an inhibitory effect on the twisting of the main chain, so the compounding system adding the bisphenol A novolac epoxy resin can further improve the glass transition temperature Tg and the resistance to heat after curing. Moisture and heat resistance; at the same time, by increasing the active groups in the molecular structure to form strong chemical bonds during the curing process, the adhesion of the coating is enhanced, so that the coating can be firmly attached to the surface of the substrate, and the water resistance of the coating is also improved at the same time, effectively preventing moisture from penetrating the paint film, and even in a closed and humid environment, it can effectively avoid problems such as blistering, shedding, and corrosion of the coating; in addition, the Mannich base curing agent also exhibits strong hydrophobicity, permeability resistance, bonding strength, and rapid curing. It can effectively cure phenolic epoxy resin in low temperature or high temperature and high humidity environments. Effective curing broadens the adaptability to the spraying environment, and the cured paint film not only has excellent water resistance, can resist the erosion of chemicals such as acids, alkalis, and salts, but also enhances the flexibility of the phenolic epoxy resin coating, improves the impact resistance and bending resistance of the paint film, and the quick-drying characteristics not only avoid the use of epoxy accelerators, but also improves production efficiency.

[0056] Specifically, in the present invention, the wetting dispersant is composed of a copolymer dispersant containing an acidic group and a modified polyurethane dispersant. In a preferred embodiment of the present invention, the copolymer dispersant containing an acidic group is at least one of BYK-110, BYK-111, MOK-5611, and HY-9010; and the modified polyurethane dispersant is at least one of Efka4060, Efka PU 4063, and Efka PU4061.

[0057] In the present invention, the compounded wetting and dispersing agent can effectively reduce the surface tension of the pigment and filler, promote its uniform dispersion in the coating system, improve the leveling property of the coating, and prevent the occurrence of floating color and blooming; the acidic group in the copolymer dispersant containing the acidic group reacts chemically with the metal substrate to form a strong chemical bond, and the addition of the modified polyurethane dispersant further enhances the cohesion of the coating and the bonding force with the substrate, and the synergistic effect of the two improves the adhesion of the coating, making the coating more stable, and after the modified polyurethane with water resistance, temperature resistance and chemical resistance is compounded with the copolymer containing the acidic group, the moisture and heat resistance and corrosion resistance of the coating are further improved, and the service life of the coating is extended; in addition, the VOC content of the above-mentioned wetting and dispersing agent is low, so the purpose of reducing VOC in the coating is achieved.

[0058] Specifically, in the present invention, the adhesion promoter is composed of titanate and aromatic polyether polyol. In a preferred embodiment of the present invention, the titanate is at least one of isopropoxy tris(dioctyl pyrophosphate acyloxy) titanate, bis(dioctyl pyrophosphate acyloxy) ethylene titanate, isopropyl dioleyloxy (dioctyl pyrophosphate acyloxy) titanate, and isopropyl tris(dioctyl pyrophosphate acyloxy) titanate; the aromatic polyether polyol is at least one of bishydroxypropyl bisphenol fluorene ether and bishydroxyethyl bisphenol fluorene ether.

[0059] In the present invention, after the titanate adhesion promoter is compounded with the aromatic polyether polyol, the aromatic rings with high thermal stability and rigidity contained in the aromatic polyether polyol molecules and the functional groups in the aromatic polyether polyol interact with the titanate, so that the compounded titanate and the aromatic polyether polyol can maintain the integrity and stability of the molecular structure during changes in temperature and humidity. In addition, the aromatic polyether polyol participates in the curing reaction to make the cured coating denser, which can better block the penetration of water vapor or chemical media, reduce the accumulation of water vapor at the interface between the coating and the substrate and the effect on adhesion; in addition, the flexible chain segments of the aromatic polyether polyol can also absorb the stress generated by thermal expansion, further stabilizing the bonding force between the coating and the substrate. The present invention improves the adhesion of the coating in a humid, high-temperature or low-temperature environment or after being subjected to temperature changes by selecting an aromatic polyether polyol and a titanate ester for compounding, thereby ensuring the integrity and protective effectiveness of the coating. The compounded adhesion promoter can increase the density of the coating film layer, improve the thermal shielding effect of the coating, and improve the moisture and heat resistance, water resistance, flexibility, and chemical corrosion resistance of the coating, so that the coating is not easy to soften, deform, or lose adhesion in a high-temperature environment, and can resist the erosion of various acids, alkalis, salts and other chemical substances.

[0060] Specifically, in the present invention, the thixotropic agent is composed of organic bentonite and polyamide wax slurry. In a preferred embodiment of the present invention, the organic bentonite is at least one of CARH-D10, BENTONE 38, HFGEL-40D, and HFGEL-127; the polyamide wax slurry is at least one of HS SF-3620, LRH-467, and MT6900-20X.

[0061] In the present invention, the compounded thixotropic agent not only further enhances the thixotropy and dispersibility of the coating through synergistic effect, making the coating more uniform and stable during the construction process, improving the appearance of the paint film, but also shortens the drying time of the paint film and improves the construction efficiency; in addition, the thixotropic agent has a low VOC content, thereby achieving the purpose of reducing VOC in the coating.

[0062] Specifically, in the present invention, the pigment is composed of a color pigment and a zinc phosphate antirust pigment. In a preferred embodiment of the present invention, the color pigment is at least one of titanium dioxide, organic orange, phthalocyanine blue, carbon black, iron oxide red, and iron oxide yellow.

[0063] In the present invention, the compounded pigment can not only improve the hiding power and adhesion of the coating through the synergistic effect, but also form a dense protective film with the metal substrate, effectively blocking the intrusion of corrosive media such as moisture and oxygen, and enhancing the overall protective ability of the coating.

[0064] Specifically, in the present invention, the filler is composed of a hydrophobic filler and precipitated barium sulfate. In a preferred embodiment of the present invention, the hydrophobic filler is at least one of mica powder, nano-silicon dioxide, polytetrafluoroethylene powder, organic silicon powder, graphite powder, and glass flakes.

[0065] In the present invention, the hydrophobic filler can be evenly dispersed in the anti-corrosion coating provided by the present invention, and form a dense protective film on the metal substrate, effectively blocking the intrusion of corrosive media such as moisture and oxygen, and enhancing the overall protective ability of the coating. The compounded filler synergistically improves the water resistance and adhesion of the coating after the temperature change test, and further improves the leveling and thixotropy of the coating, thereby improving the flatness and appearance of the coating.

[0066] Specifically, in the present invention, solvent A and solvent B are preferably at least one of xylene, n-butanol, propylene glycol methyl ether, and propylene glycol methyl ether acetate. In the present invention, the amount of solvent used in the coating is reduced by using a low volatility solvent.

[0067] Specifically, in the present invention, the addition amount of each component in component A is: by weight, 30-45 parts of phenolic epoxy resin; 0.1-3 parts of wetting dispersant; 0.5-2 parts of adhesion promoter; 0.5-3 parts of thixotropic agent; 15-30 parts of pigment; 15-30 parts of filler; 10-15 parts of solvent A; the addition amount of each component in component B is: by weight, 90-95 parts of nixi base curing agent; 5-10 parts of solvent B. Controlling the amount of each component within the above range can improve the moisture and heat resistance, corrosion resistance, temperature change cycle resistance, flexibility and adhesion of the phenolic epoxy anticorrosive coating.

[0068] In a preferred embodiment of the present invention, in the novolac epoxy resin, the amount of phenol-type novolac epoxy resin added is 10 to 20 parts by weight, and the amount of bisphenol A novolac epoxy resin added is 20 to 25 parts by weight; in the wetting dispersant, the amount of the copolymer dispersant containing an acidic group and the modified polyurethane dispersant added are both 0.05 to 1.5 parts by weight; in the adhesion promoter, the amount of titanate added is 0.3 to 1 part by weight, and the amount of aromatic polyether polyol added is 0.2 to 1 part by weight; in the thixotropic agent, the amount of organic bentonite and polyamide wax slurry added is both 0.25 to 1.5 parts by weight; in the pigment, the amount of color pigment added is 10 to 20 parts by weight, and the amount of zinc phosphate antirust pigment added is 5 to 15 parts by weight; in the filler, the amount of hydrophobic filler added is 5 to 10 parts by weight, and the amount of precipitated barium sulfate added is 10 to 20 parts by weight.

[0069] Based on the above-mentioned phenolic epoxy anticorrosion coating, the present invention provides a method for preparing the phenolic epoxy anticorrosion coating, comprising the steps of:

[0070] S1. Prepare component A: add phenolic epoxy resin, wetting dispersant, adhesion promoter, thixotropic agent, pigment and filler into a dispersion kettle according to the proportion, add a portion of solvent A, stir evenly, transfer to a grinder and grind to a fineness of ≤50 μm, then add a portion of solvent A to adjust the viscosity to 90-100 KU, and obtain component A after filtering;

[0071] S2. Prepare component B: put the curing agent and solvent B into the batching tank in sequence according to the ratio, and stir evenly to obtain component B;

[0072] S3. Evenly mix component A and component B in a mass ratio of 5 to 7:1 to obtain the phenolic epoxy anticorrosive coating.

[0073] In a preferred embodiment of the present invention, the specific preparation process of component A in step S1 is:

[0074] S11, adding a portion of solvent A and phenolic epoxy resin into the dispersion kettle in sequence, and stirring for 10-20 minutes;

[0075] S12, add the wetting dispersant and adhesion promoter into the dispersion kettle in sequence, and stir for 10-20 minutes;

[0076] S13, add the thixotropic agent into the dispersion kettle, control the speed to 1500-2000 r / min, and disperse at high speed for 10-30 minutes;

[0077] S14, add the pigment and filler into the dispersion kettle in sequence, disperse at high speed for 10-30 minutes, and then grind to a fineness of ≤50μm;

[0078] S15. Use the remaining solvent A to adjust the viscosity to 90-100 KU, and filter with a filter to obtain component A.

[0079] Based on the above-mentioned phenolic epoxy anti-corrosion coating, the present invention also provides an application of the phenolic epoxy anti-corrosion coating as an anti-corrosion coating on a metal substrate under an insulation layer, and the application temperature thereof can reach 250°C.

[0080] Example 1

[0081] This embodiment provides a phenolic epoxy anticorrosive coating, and the preparation process thereof is as follows:

[0082] S1. Preparation of component A: First, add 2 parts of xylene, 20 parts of NPPN-631, and 25 parts of F-51 to a dispersion kettle in order and stir for 10 minutes; then add 1 part of BYK110, 1 part of Efka4060, 1 part of isopropoxy tris (dioctyl pyrophosphate acyloxy) titanate, and 1 part of bishydroxypropyl bisphenol fluorene ether to a dispersion kettle in order and stir for 2 minutes; then add 0.5 parts of CARH-D10, 0.5 parts of BENTONE 38, and 1 part of HS SF-3620 to the dispersion kettle, and control the speed to 1500. r / min, high-speed dispersion for 10 minutes; then add 10 parts of titanium dioxide, 5 parts of red iron oxide, 15 parts of zinc phosphate, 10 parts of mica powder, and 10 parts of precipitated barium sulfate into the dispersion kettle in sequence, disperse at high speed for 20 minutes, transfer to the grinder, and grind to a fineness of ≤50µm; finally, add 8 parts of n-butanol to adjust the viscosity to 90KU, and filter through a 150-mesh filter to obtain component A;

[0083] S2. Preparation of component B: by weight, 90 parts of T33 and 5 parts of xylene are sequentially added into a batching tank and stirred to obtain component B;

[0084] S3. Evenly mix component A and component B in a mass ratio of 5:1 to obtain a phenolic epoxy anticorrosive coating.

[0085] Example 2

[0086] This embodiment provides a phenolic epoxy anticorrosive coating, and the preparation process thereof is as follows:

[0087] S1. Preparation of component A: First, by weight, 3 parts of propylene glycol methyl ether, 15 parts of NPPN-638S, and 20 parts of BNE200 were added to a dispersion kettle in sequence and stirred for 15 minutes; then 0.02 parts of BYK-111, 0.03 parts of MOK-5611, 0.05 parts of Efka PU4063, 0.3 parts of bis(dioctyl pyrophosphate)ethylene titanate, and 0.2 parts of bis(hydroxyethyl)bisphenol fluorene ether were added to a dispersion kettle in sequence and stirred for 6 minutes; then 0.25 parts of HFGEL-40D and 0.25 parts of LRH-467 were added to the dispersion kettle, and the speed was controlled at 1800. r / min, high-speed dispersion for 20 minutes; then 10 parts of organic orange, 5 parts of zinc phosphate, 5 parts of nano-silicon dioxide, and 10 parts of precipitated barium sulfate were added to the dispersion kettle in sequence, high-speed dispersion for 20 minutes, transferred to the grinder, and ground to a fineness of ≤50µm; finally, 9 parts of propylene glycol methyl ether were added to adjust the viscosity to 95KU, and filtered through a 150-mesh filter to obtain component A;

[0088] S2. Prepare component B: by weight, add 93 parts of T33 and 10 parts of propylene glycol methyl ether acetate into a batching tank in sequence, and stir evenly to obtain component B;

[0089] S3. Evenly mix component A and component B in a mass ratio of 6:1 to obtain a phenolic epoxy anticorrosive coating.

[0090] Example 3

[0091] This embodiment provides a phenolic epoxy anticorrosive coating, and the preparation process thereof is as follows:

[0092] S1. Preparation of component A: First, by weight, 5 parts of xylene, 5 parts of PNE177, 5 parts of Kep1131, 10 parts of F-51, and 10 parts of BNE200 were added to a dispersion kettle in sequence and stirred for 20 minutes; then 1.5 parts of HY-9010, 1.5 parts of Efka PU 4061, 0.2 parts of isopropyl dioleic acid acyloxy (dioctyl phosphate acyloxy) titanate, 0.3 parts of isopropyl tris (dioctyl pyrophosphate acyloxy) titanate, 0.2 parts of bishydroxypropyl bisphenol fluorene ether, and 0.3 parts of bishydroxyethyl bisphenol fluorene ether were added to a dispersion kettle in sequence and stirred for 10 minutes; then 1.5 parts of HFGEL-127, 0.5 parts of LRH-467, and 1 part of MT6900-20X were added to the dispersion kettle, and the speed was controlled at 2000. r / min, high-speed dispersion for 30 minutes; then 10 parts of carbon black, 10 parts of red iron oxide, 10 parts of zinc phosphate, 5 parts of polytetrafluoroethylene powder, 5 parts of organic silicon powder, and 20 parts of precipitated barium sulfate are added to the dispersion kettle in sequence, dispersed at high speed for 20 minutes, transferred to the grinder, and ground to a fineness of ≤50µm; finally, 10 parts of xylene are added to adjust the viscosity to 100KU, and filtered through a 150-mesh filter to obtain component A;

[0093] S2. Prepare component B: by weight, add 95 parts of T33 and 8 parts of propylene glycol methyl ether acetate into a batching tank in sequence, and stir evenly to obtain component B;

[0094] S3. Evenly mix component A and component B in a mass ratio of 7:1 to obtain a phenolic epoxy anticorrosive coating.

[0095] Comparative Example 1

[0096] The difference between this comparative example and Example 1 is that the bisphenol A type novolac epoxy resin F-51 is replaced by an equal amount of phenol type novolac epoxy resin NPPN-631, and the Mannich base curing agent T33 is replaced by an equal amount of alicyclic amine curing agent Baxxodur EC 331, and the other parts are the same.

[0097] Comparative Example 2

[0098] The difference between this comparative example and Example 1 is that the aromatic polyether polyol bishydroxypropyl bisphenol fluorene ether is replaced by an equal amount of titanate adhesion promoter isopropoxy tris (dioctyl pyrophosphate acyloxy) titanate in this comparative example, and the other contents are the same.

[0099] Comparative Example 3

[0100] The difference between this comparative example and Example 1 is that in this comparative example, the copolymer BYK110 containing acidic groups is replaced by an equal amount of modified polyurethane Efka4060, and the organobentonite CARH-D10 and BENTONE 38 are replaced by an equal amount of polyamide wax slurry HS SF-3620.

[0101] Comparative Example 4

[0102] The difference between this comparative example and Example 1 is that in this comparative example, zinc phosphate is replaced by an equal amount of titanium dioxide and red iron oxide in a mass ratio of 2:1, and mica powder is replaced by an equal amount of precipitated barium sulfate.

[0103] According to the performance indicators in Table 1, the performance of the phenolic epoxy anti-corrosion coatings prepared in Examples 1-3 and Comparative Examples 1-4 was tested respectively, and the product implementation standard was combined with "HG / T 5178-2017 Anti-corrosion coatings for metal surfaces under insulation layer".

[0104] Table 1 Test items and performance test indicators of anti-corrosion coatings

[0105]

[0106] The test results of the above examples 1-3 are shown in Table 2 below.

[0107] Table 2 Performance test results of Examples 1-3

[0108]

[0109] It can be seen from the performance test results in Table 2 above that the phenolic epoxy anti-corrosion coatings prepared in Examples 1-3 have excellent moisture and heat resistance, corrosion resistance, high adhesion and high flexibility. After the temperature change resistance test, the anti-corrosion coatings still meet the requirements of the "HG / T5178-2017 Anti-corrosion Coatings for Metal Surfaces Under Insulation Layer" implementation standard.

[0110] The test results of the above comparative examples 1-4 are shown in Table 3 below.

[0111] Table 3 Performance test results of comparative examples 1-4

[0112]

[0113] It can be seen from the performance test results in Table 3 above that the comprehensive performance of the phenolic epoxy anticorrosive coatings prepared in Comparative Examples 1-4 is relatively poor.

[0114] According to the test results of Table 2 and Table 3 above, Example 1 is compared with Comparative Examples 1-4 respectively:

[0115] Comparing Example 1 with Comparative Example 1, Example 1 uses phenol-type novolac epoxy resin and bisphenol A novolac epoxy resin to compound with Mannich base curing agent to prepare novolac epoxy anti-corrosion coating, and Comparative Example 1 uses pure phenol-type novolac epoxy resin and alicyclic amine curing agent to prepare anti-corrosion coating. The flexibility, impact resistance, moisture and heat resistance, chemical corrosion resistance, and temperature change cycle resistance of Example 1 are better than those of Comparative Example 1, and after the temperature change resistance test, the adhesion, water resistance, salt spray resistance, and condensation water resistance of Example 1 are also better than those of Comparative Example 1. The phenolic epoxy anti-corrosion coating prepared by compounding phenolic epoxy resin and bisphenol A phenolic epoxy resin with Mannich base curing agent in Example 1 is suitable for the protection of metal under the insulation layer. However, the coating prepared by pure phenolic epoxy resin and alicyclic amine curing agent in Comparative Example 1 has decreased adhesion after the temperature change test, and the salt spray resistance, water resistance and other properties also decrease accordingly, and is not suitable for the protection of metal under the insulation layer.

[0116] Comparing Example 1 with Comparative Example 2, the adhesion promoter of Example 1 is a compound of aromatic polyether polyol and titanate, which improves the flexibility, impact resistance, moisture and heat resistance, chemical corrosion resistance and adhesion after temperature change test, water resistance, salt spray resistance and other properties of the phenolic epoxy anti-corrosion coating, while the anti-corrosion coating prepared by Comparative Example 2 using only titanate adhesion promoter cannot achieve long-term corrosion protection of the metal substrate. This is because in Comparative Example 2, only titanate is used as an adhesion promoter. Titanate combines with the metal compound on the surface of the metal substrate through the coordination function, and can interact with the functional groups on the resin molecular chain to form a strong chemical bridge bond between the metal substrate and the epoxy resin. Although the adhesion of the coating can be improved to a certain extent, in a humid environment and temperature changes, water vapor under the insulation layer gradually penetrates into the interior of the coating and accumulates at the interface between the coating and the substrate, destroying the bond between the coating and the substrate, thereby reducing the adhesion. The humid environment will also affect the stability of titanate, thereby affecting the adhesion of the coating. In addition, since the internal stress generated by temperature changes cannot be eliminated, it will further destroy the bonding between the coating and the substrate, thereby causing the adhesion to be further reduced, and ultimately accelerating the shedding of the anti-corrosion coating, making it impossible to achieve long-term protection.

[0117] Example 1 is compared with Comparative Example 3. Example 1 improves the rheology, construction properties, moisture and heat resistance, and corrosion resistance of the coating by using a wetting and dispersing agent composed of a copolymer containing an acidic group and a modified polyurethane and a thixotropic agent composed of an organic bentonite and a polyamide wax slurry, shortens the drying time of the paint film, improves the appearance of the paint film, and also improves the adhesion, water resistance, salt spray resistance, condensation water resistance and other properties of the paint film after the temperature change test.

[0118] Example 1 is compared with Comparative Example 4. The pigment of Example 1 is a compound of ordinary color-developing pigment and zinc phosphate anti-rust pigment, and the filler is a compound of hydrophobic filler and precipitated barium sulfate, which effectively improves the overall protective ability of the coating, improves the adhesion, water resistance and salt spray resistance after the temperature change test, and has better anti-corrosion performance.

[0119] The phenolic epoxy anticorrosive coating of the present invention is used in high temperature, high humidity and complex corrosion environment under the insulation layer. It has excellent moisture and heat resistance, adhesion, flexibility and resistance to chemical media. It can not only withstand high temperature and prevent metal corrosion, but also has good construction performance and environmental protection characteristics, and can be suitable for complex industrial environments.

[0120] It should be noted that some parts not described in the present invention can be implemented by adopting or drawing on existing technologies.

[0121] Of course, the above description is not a limitation of the present invention, and the present invention is not limited to the above examples. Changes, modifications, additions or substitutions made by technicians in this technical field within the essential scope of the present invention should also fall within the protection scope of the present invention.

Claims

1. A phenolic epoxy anticorrosive coating, characterized in that: It includes component A and component B; Component A includes the following ingredients in parts by weight: 30-45 parts of phenolic epoxy resin; Wetting and dispersing agent 0.1~3 parts; Adhesion promoter 0.5~2 parts; Thixotropic agent 0.5~3 parts; Pigment 15~30 parts; 15~30 parts of filler; Solvent A 10-15 parts; The novolac epoxy resin is composed of phenol-type novolac epoxy resin and bisphenol A-type novolac epoxy resin; The wetting dispersant is composed of a copolymer dispersant containing an acidic group and a modified polyurethane dispersant; The adhesion promoter is composed of titanate and aromatic polyether polyol; The thixotropic agent consists of organic bentonite and polyamide wax slurry; The pigment consists of a color-developing pigment and a zinc phosphate anti-rust pigment; The filler is composed of a hydrophobic filler and precipitated barium sulfate; Component B includes the following ingredients in parts by weight: 90-95 parts of Mannich base curing agent; Solvent B 5-10 parts; When in use, component A and component B are mixed in a mass ratio of 5 to 7:

1.

2. A phenolic epoxy anticorrosive coating according to claim 1, characterized in that: The amount of the phenol-type novolac epoxy resin added is 10 to 20 parts by weight, and the amount of the bisphenol A-type novolac epoxy resin added is 20 to 25 parts by weight; The phenol-type novolac epoxy resin is at least one of NPPN-631, NPPN-638S, PNE177, and Kep1131; The bisphenol A novolac epoxy resin is at least one of F-51 and BNE200.

3. A phenolic epoxy anticorrosive coating according to claim 1, characterized in that: The Mannich base curing agent is T33.

4. A phenolic epoxy anticorrosive coating according to claim 1, characterized in that: The added amounts of the copolymer dispersant containing an acidic group and the modified polyurethane dispersant are both 0.05 to 1.5 parts by weight; The amount of titanate added is 0.3-1 parts by weight, and the amount of aromatic polyether polyol added is 0.2-1 parts by weight; The added amounts of organic bentonite and polyamide wax slurry are both 0.25-1.5 parts by weight.

5. A phenolic epoxy anticorrosive coating according to claim 4, characterized in that: The copolymer dispersant containing an acidic group is at least one of BYK-110, BYK-111, MOK-5611, and HY-9010; The modified polyurethane dispersant is at least one of Efka4060, Efka PU 4063 and Efka PU 4061; The titanate is at least one of isopropoxy tris (dioctyl pyrophosphate acyloxy) titanate, bis (dioctyl pyrophosphate acyloxy) ethylene titanate, isopropyl dioleyl acyloxy (dioctyl pyrophosphate acyloxy) titanate, and isopropyl tris (dioctyl pyrophosphate acyloxy) titanate; The aromatic polyether polyol is at least one of bishydroxypropyl bisphenol fluorene ether and bishydroxyethyl bisphenol fluorene ether; The organic bentonite is at least one of CARH-D10, BENTONE 38, HFGEL-40D, and HFGEL-127; The polyamide wax slurry is at least one of HS SF-3620, LRH-467, and MT6900-20X.

6. A phenolic epoxy anticorrosive coating according to claim 1, characterized in that: The amount of color pigment added is 10 to 20 parts by weight, and the amount of zinc phosphate antirust pigment added is 5 to 15 parts by weight; The amount of the hydrophobic filler added is 5 to 10 parts by weight, and the amount of the precipitated barium sulfate added is 10 to 20 parts by weight.

7. A phenolic epoxy anticorrosive coating according to claim 6, characterized in that: The color pigment is at least one of titanium dioxide, organic orange, phthalocyanine blue, carbon black, iron oxide red, and iron oxide yellow; The hydrophobic filler is at least one of mica powder, nano silicon dioxide, polytetrafluoroethylene powder, organic silicon powder, graphite powder and glass flakes.

8. A phenolic epoxy anticorrosive coating according to claim 1, characterized in that: The solvent A and the solvent B are at least one of xylene, n-butanol, propylene glycol methyl ether, and propylene glycol methyl ether acetate.

9. A method for preparing a phenolic epoxy anticorrosive coating, for preparing the anticorrosive coating according to any one of claims 1 to 8, characterized in that: Includes steps: S1. Prepare component A: add phenolic epoxy resin, wetting dispersant, adhesion promoter, thixotropic agent, pigment and filler into a dispersion kettle according to the proportion, add a portion of solvent A, stir evenly, transfer to a grinder and grind to a fineness of ≤50 μm, then add another portion of solvent A to adjust the viscosity to 90-100 KU, and obtain component A after filtering; S2, preparing component B: adding the Mannich base curing agent and solvent B into a batching tank in sequence according to the proportion, and stirring evenly to obtain component B; S3. Evenly mix component A and component B in a mass ratio of 5 to 7:1 to obtain the phenolic epoxy anticorrosive coating.

10. Use of the phenolic epoxy anti-corrosion coating as claimed in any one of claims 1 to 8 as an anti-corrosion coating on a metal substrate under an insulation layer.

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