High-temperature cathode delamination-resistant solvent-free coating and preparation method

Abstract

The application discloses a high-temperature anti-cathode peeling solvent-free paint and a preparation method. The paint comprises component A and component B which cooperate with each other. The component A comprises epoxy resin, active diluent, anti-corrosion viscosity reducer, organic silicon defoaming agent, polyamide wax thixotropic agent, pigment and filler. The component B comprises amine adduct, N-aminoethyl piperazine and adhesion promoter. The paint is used in a weight ratio of A:B=(3-6):1. The amine adduct and N-aminoethyl piperazine in the application are used as curing agents, which can improve the curing crosslinking density of the paint film on one hand, and further introduce nitrogen atom structure into the cured paint film to improve the wet adhesion, alkali resistance and anti-cathode peeling performance of the paint film on the other hand. The second curing agent component N-aminoethyl piperazine can improve the glass transition temperature of the paint film in a high-temperature environment, and finally meet the high-temperature anti-cathode peeling requirement.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of chemical coatings, in particular to a high-temperature cathodic disbonding resistant solvent-free coating and a preparation method thereof. BACKGROUND

[0002] For metal steel structures buried or immersed in seawater, the combined application of cathodic protection and organic coating is the most economical and effective protection method. Through the combined use of organic coating and cathodic protection, on the one hand, the possible pinholes, defects, failures, etc. of the organic coating itself can be protected by cathodic protection, thereby preventing possible corrosion of the substrate; on the other hand, the shielding effect of the organic coating can greatly reduce the protection current required in the cathodic protection process, thereby greatly saving the sacrificial anode, reducing energy consumption, and saving energy. However, cathodic protection can cause the loss of adhesion of the organic coating / metal substrate interface, further causing the disbonding between the organic coating and the substrate, which is the cathodic disbonding of the organic coating under cathodic protection. Cathodic disbonding not only leads to coating failure, but also gradually increases the protection current in the cathodic protection process, leading to energy and non-ferrous metal waste, and bringing great difficulty and uncertainty to the cathodic protection engineering design and maintenance process. Therefore, when organic coatings are used in combination with cathodic protection, the cathodic disbonding resistance of the organic coating is particularly important. When organic coatings are used in combination with cathodic protection, the organic coating is required to have excellent cathodic disbonding resistance.

[0003] With the continuous development of deepwater oil and gas field development in the field of offshore oil and gas, deepwater submarine pipelines are increasingly widely used. The coating design of deepwater submarine pipelines is generally determined according to the actual corrosion environment. With the increase of the temperature of the medium transported in the pipeline, when organic coatings are used in combination with cathodic protection, the cathodic disbonding of the organic coating under high temperature conditions is aggravated, and the increase of cathodic disbonding further increases the current required for cathodic protection, shortening the service life of the cathodic protection system. Therefore, when organic coatings are used in combination with cathodic protection for high-temperature pipelines, higher requirements are placed on the cathodic disbonding resistance of the organic coating, and the organic coating is required to have excellent high-temperature cathodic disbonding resistance.

[0004] Therefore, it is necessary to develop a high-temperature cathodic disbonding resistant solvent-free coating for use in combination with cathodic protection for high-temperature pipelines, which has excellent high-temperature cathodic disbonding resistance. SUMMARY

[0005] The main purpose of the present application is to provide a high-temperature cathodic disbonding resistant solvent-free coating and a preparation method thereof, which has excellent high-temperature cathodic disbonding resistance and meets the requirements of use in combination with cathodic protection under high-temperature conditions.

[0006] To achieve the above object, one aspect of the present application provides a high-temperature cathode stripping resistant solvent-free coating, which is composed of two components A and B, wherein the component A comprises the following components in parts by weight:

[0007] epoxy resin 30-40 parts;

[0008] active diluent 10-15 parts;

[0009] corrosion and viscosity reducing agent 0.5-1.5 parts;

[0010] silicone defoamer 0.5-1 part;

[0011] polyamide wax thixotropic agent 0.5-1 part;

[0012] pigment 10-20 parts;

[0013] filler 20-45 parts;

[0014] The component B comprises the following components in parts by weight:

[0015] amine adduct 50-70 parts;

[0016] N-aminoethylpiperazine 20-40 parts;

[0017] adhesion promoter 5-10 parts;

[0018] wherein the weight ratio of component A to component B is (3-6):1.

[0019] Further, the epoxy resin of the component A is any one or a combination of two of bisphenol F epoxy resin and phenolic epoxy resin, and the epoxy functionality thereof is 2.1-2.4.

[0020] Further, the active diluent of the component A is a bifunctional glycidyl ether diluent.

[0021] Further, the corrosion and viscosity reducing agent is a functional silane dispersant, preferably Wacker SIVO240.

[0022] Further, the pigment is any one or a combination of two of rutile titanium dioxide and carbon black.

[0023] Further, the filler is any two or more of a combination of quartz powder, feldspar powder, wollastonite and mica powder.

[0024] Further, the amine adduct of the B component is an adduct of a di-alicyclic amine or an aralicyclic amine and N,N,N',N'-tetra(oxymethylene methyl)-1,3-benzenedimethylamine, preferably the di-alicyclic amine is one or a mixture of two or more of 1,3-cyclohexanedimethylamine, cyclohexanediamine or isophorone diamine, and the aralicyclic amine is m-xylylenediamine.

[0025] Further, the adhesion promoter of the B component is either one or a combination of both of bis(3-triethoxysilyl)propylamine and bis(3-trimethoxysilyl)propylamine.

[0026] Another aspect of the present application provides a method for preparing a high-temperature cathode delamination resistant solvent-free coating, the specific steps are as follows:

[0027] (1) Synthesis of component A

[0028] a. Add the epoxy resin and active diluent, stir at low speed until uniform, then add the corrosion inhibitor and viscosity reducer, defoamer and rheological aid, stir at medium speed until uniform, to obtain a stock solution;

[0029] b. Add pigments and fillers to the stock solution, stir at low speed until uniform, then disperse at high speed for 1.5-2 hours, control the temperature at 55-60°C during the stirring process, and control the fineness to be less than 80um, to obtain component A;

[0030] (2) Synthesis of component B

[0031] a. First, add 30-40 moles of di-amine to the reaction kettle, stir at a speed of 600-800 rpm, and control the temperature at 25-35°C using a water bath;

[0032] b. Dilute 1.5-2 moles of N,N,N',N'-tetra(oxymethylene methyl)-1,3-benzenedimethylamine with 1 mole of propylene glycol methyl ether, and add it dropwise to the reaction kettle of step a within 5-6 hours, then control the temperature at 25-35°C for 5-6 hours, and maintain the stirring speed at 600-800 rpm and the temperature at 25-35°C during the dropping and incubation processes;

[0033] c. Heat the material obtained in step b to 180-200°C, and distill it under a vacuum degree of at least 740 mmHg, first distilling out the propylene glycol methyl ether solvent, and then distilling out the unreacted di-amine, until no liquid is distilled out;

[0034] d. Take 50-70 parts by mass of the material obtained in step c, heat it to control the temperature at 80-90°C, add 20-40 parts of N-aminoethylpiperazine, stir at low speed until uniform, cool it to room temperature, then add 5-10 parts of the adhesion promoter, and stir at low speed until uniform to obtain component B,

[0035] (3) Use A and B components mixed with (3-6): 1.

[0036] The principle of the role of the amine adduct in component B in the present application is as follows: (a) increasing the active hydrogen functionality of the curing agent, improving the crosslinking density of the cured paint film, and ensuring excellent cathodic disbondment resistance under high temperature conditions. By controlling the addition process, N,N,N',N'-tetra(oxymethylene methyl)-1,3-benzene dimethylamine is added dropwise in a large excess of diamine, and after complete reaction, the unreacted diamine is removed, and the active hydrogen functionality of the final curing agent can reach 12. Using this adduct to react with component A, the glass transition temperature of the cured paint film is greatly improved, ensuring that the cured paint film is still in a glass state even under high temperature cathodic disbondment test conditions, thereby providing excellent electrolyte permeability and insulation shielding effect; (b) further introducing nitrogen-containing atomic structures into the molecular structure of the cured paint film, greatly improving the wet adhesion and cathodic disbondment resistance of the cured paint film. A large number of studies have shown that the alkaline environment generated at the "coating-metal substrate" interface under the action of cathodic protection is one of the main reasons for the peeling of the organic coating and the metal substrate interface, and the lone pair of electrons on the nitrogen atom can provide excellent wet adhesion and cathodic disbondment resistance under alkaline conditions. The molecular structure of N,N,N',N'-tetra(oxymethylene methyl)-1,3-benzene dimethylamine contains two nitrogen atom structures, and the addition of diamine and N,N,N',N'-tetra(oxymethylene methyl)-1,3-benzene dimethylamine can ensure that the cured paint film has excellent cathodic disbondment resistance. Therefore, the present patent uses the adduct of diamine and N,N,N',N'-tetra(oxymethylene methyl)-1,3-benzene dimethylamine as a curing agent.

[0037] The principle of the action of the disilane coupling agent in component B as an adhesion promoter in the present application is as follows: the disilane coupling agent in the present application mainly includes one of bis(3-triethoxysilyl)propylamine, bis(3-trimethoxysilyl)propylamine or a mixture of the two. Traditional amino silane coupling agents generally only contain one silicon group and contain primary amine structures, while the disilane coupling agent used in the present application contains two silicon groups, and its molecule does not contain primary amine but only contains one secondary amine active hydrogen. The principle of its action specifically includes: (a) the silicon hydroxyl functionality of the disilane group in the disilane molecular structure after hydrolysis is twice that of traditional silane coupling agents, and its functionality of forming chemical bonds with the hydroxyl groups on the surface of the substrate through condensation reaction is higher, so it can greatly improve the wet adhesion of the paint film compared with traditional silane coupling agents, and ensure that the paint film has excellent cathodic disbonding resistance; (b) the primary amine in the traditional amino silane coupling agent is at one end of the molecular structure, and when mixed with the epoxy component as part of the curing agent, it is easy to react with the epoxy groups to form oligomers and further crosslink to form macromolecules. The silane coupling agent after the reaction is difficult to migrate to the substrate surface due to the large increase in molecular weight, so the amount of silane coupling agent that can actually migrate to the substrate surface and react with the substrate is very limited, which is very limited for improving adhesion. The secondary amine in the disilane coupling agent in the present application is only in the molecular chain segment, so the reactivity of the secondary amine is obviously lower than that of the primary amine in the traditional silane coupling agent. When mixed with the epoxy groups in component A, the disilane coupling agent first migrates to the substrate surface, hydrolyzes on the substrate surface and condenses with the hydroxyl groups on the substrate surface to form chemical bonds; on this basis, the secondary amine in the disilane molecule can further react with the epoxy groups to ensure that the paint film is anchored to the substrate through chemical bonds, so it can significantly improve the cathodic disbonding resistance compared with traditional silane coupling agents.

[0038] The principle of the action of N-aminoethylpiperazine as the second curing agent in component B of the present application is as follows: for paint films with a relatively high crosslinking density, it is difficult to completely cure at room temperature, and when the environmental temperature increases, further post-curing will occur, which can further improve the curing degree and glass transition temperature of the paint film.

[0039] The beneficial effects of the technical scheme of the present application are as follows:

[0040] (1) The first curing agent component used in component B of the present application is the adduct of diamine and N,N,N',N'-tetra(oxirane-methyl)-1,3-benzene dimethylamine, which has the following beneficial effects: on the one hand, it improves the curing crosslinking density of the paint film to ensure that it meets the use requirements under high-temperature cathodic disbonding test conditions; on the other hand, through molecular design, it further introduces nitrogen atom structures into the cured paint film to improve the wet adhesion, alkali resistance and cathodic disbonding resistance of the paint film, and ultimately meet the high-temperature cathodic disbonding requirements.

[0041] (2) The component B of the present application uses a double silane coupling agent as an adhesion promoter, which can greatly improve the wet adhesion of the paint film compared with the traditional silane coupling agent, and ensure that the paint film has excellent cathodic disbondment resistance; in the present application, after the double silane coupling agent is mixed with the epoxy group of component A, due to the low reactivity and small polarity of the double silane coupling agent molecule, the double silane coupling agent first migrates to the surface of the substrate, hydrolyzes on the surface of the substrate and condenses with the hydroxyl group on the surface of the substrate to form a chemical bond; on this basis, the secondary amine in the double silane molecule can further react with the epoxy group to ensure that the paint film and the substrate are anchored by a chemical bond, so the cathodic disbondment resistance can be significantly improved compared with the traditional silane coupling agent.

[0042] (3) The component B of the present application uses N-aminoethyl piperazine as a second curing agent, which has excellent anionic ring-opening promotion curing effect under high temperature conditions. During the high-temperature cathodic disbondment process, the high-temperature conditions are further used to promote the ring-opening curing of the epoxy group, further improve the glass transition temperature of the paint film, and meet the requirements of high-temperature cathodic disbondment resistance.

[0043] The high-temperature cathodic disbondment-free solvent-based paint of the present application has excellent high-temperature cathodic disbondment resistance compared with common solvent-free paints, and meets the requirements of combined use of organic coating and cathodic protection under deep-sea high-temperature conditions. DETAILED DESCRIPTION

[0044] To make the purpose, technical scheme and advantages of the embodiments of the present application clearer, the technical scheme of the present application will be described clearly and completely below. Obviously, the described embodiments are part of the embodiments of the present application, rather than all the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative labor fall within the scope of protection of the present application.

[0045] The present application will be further described in detail below in combination with specific embodiments.

[0046] The high-temperature cathodic disbondment-free solvent-based paint comprises component A and component B, wherein component A is composed of the following components in the following weight proportions: epoxy resin 30-40 parts, active diluent 10-15 parts, corrosion inhibitor and viscosity reducer 0.5-1.5 parts, organic silicon defoaming agent 0.5-1 part, polyamide wax thixotropic agent 0.5-1 part, pigment 10-20 parts, and filler 20-45 parts; component B is composed of the following components in the following weight proportions: amine adduct 50-70 parts, N-aminoethyl piperazine 20-40 parts, and adhesion promoter 5-10 parts. When used, component A and component B are mixed in a ratio of (3-6):1.

[0047] In one embodiment, the amine adduct is prepared by chemical reaction of phenylenediamine, N,N,N',N'-tetra(oxymethylene methyl)-1,3-phenylenediamine, propylene glycol methyl ether.

[0048] In one embodiment, the amine adduct is prepared by chemical reaction of isophorone diamine, N,N,N',N'-tetra(oxymethylene methyl)-1,3-phenylenediamine, propylene glycol methyl ether.

[0049] In one embodiment, the amine adduct is prepared by chemical reaction of isophorone diamine, N,N,N',N'-tetra(oxymethylene methyl)-1,3-phenylenediamine, propylene glycol methyl ether.

[0050] Example 1

[0051] (1) Synthesis of Component A

[0052] a. Add NPEF 170 bisphenol F epoxy resin 40 parts, resorcinol diglycidyl ether 10 parts into a reaction kettle, stir uniformly at low speed, then add SIVO 240 anti-corrosion and viscosity reducer 0.6 parts, BYK-1790 defoaming agent 0.6 parts, polyamide wax Optima 0.8 parts, stir uniformly at medium speed, to obtain a stock solution;

[0053] b. Add titanium white 15 parts, feldspar powder 15 parts, mica powder 18 parts into the stock solution, stir uniformly at low speed, then disperse at high speed for 1.5 h, control the temperature at 55-60°C during stirring, control the fineness to be less than 80 um, to obtain component A;

[0054] (2) Synthesis of Component B

[0055] a. First, add 40 moles of m-phenylenediamine to the reaction kettle, stir at a speed of 600 rpm, and heat to 25-35°C with a water bath;

[0056] b. Dilute 1.5 moles of N,N,N',N'-tetra(oxymethylene methyl)-1,3-phenylenediamine with 1 mole of propylene glycol methyl ether, and slowly add it to the reaction kettle of step a, the dropping process takes 5 h, then incubate at 25-35°C for 6 hours, maintain stirring at 600 rpm and control the temperature at 25-35°C during the dropping and incubation processes;

[0057] c. Heat the material obtained in step b to 180°C, and distill under a vacuum degree of 745 mmHg, first distill off the propylene glycol methyl ether solvent, then distill off the unreacted m-phenylenediamine, until no liquid is distilled off;

[0058] d. Take the material obtained in step c above 70 parts, add N-aminoethylpiperazine 25 parts under the condition of heating control temperature 80-90°C, stir uniformly at 600 rpm and cool to room temperature, then add bis(3-trimethoxysilyl)propylamine 5 parts, stir uniformly at low speed to obtain component B.

[0059] (3) Mix component A and component B in a mass ratio of 3:1.

[0060] Example 2

[0061] (1) Synthesis of component A

[0062] a. Add EPALLOY 8240 phenolic epoxy resin 30 parts, 1,4-butanediol diglycidyl ether 15 parts to a reaction kettle, stir uniformly at low speed, then add SIVO 240 anti-corrosion and viscosity reducer 1.5 parts, BYK-1790 defoaming agent 1 part, polyamide wax Optima 0.5 part, stir uniformly at medium speed to obtain a stock solution;

[0063] b. Add titanium dioxide 10 parts, special black 6 carbon black 0.5 part, quartz powder 15 parts, feldspar powder 12 parts, mica powder 14.5 parts to the stock solution, stir uniformly at low speed, then disperse at high speed for 1.5 h, control the temperature at 55-60°C during stirring, and control the fineness to be less than 80 um to obtain component A;

[0064] (2) Synthesis of component B

[0065] a. First, add 30 moles of isophorone diamine to a reaction kettle, stir at a speed of 600 rpm, and heat to 25-35°C using a water bath;

[0066] b. Dilute 2 moles of N,N,N',N'-tetra(oxymethylene methyl)-1,3-benzene dimethylamine with 1 mole of propylene glycol methyl ether, and slowly add it to the reaction kettle of step a, the dropping process takes 6 hours, then incubate at 25-35°C for 5 hours, and maintain stirring at 600 rpm and control the temperature at 25-35°C during the dropping and incubation processes;

[0067] c. Heat the material obtained in step b to 200°C, and distill under a vacuum degree of at least 740 mmHg, first distill off the propylene glycol methyl ether solvent, then distill off the unreacted isophorone diamine, until no liquid is distilled off;

[0068] d. Take the material obtained in step c above 50 parts, add N-aminoethylpiperazine 40 parts under the condition of heating control temperature 80-90°C, stir uniformly at 600 rpm and cool to room temperature, then add bis(3-triethoxysilyl)propylamine 10 parts, stir uniformly at low speed to obtain component B.

[0069] (3) The A component and the B component are mixed in a mass ratio of 6:1.

[0070] Example 3

[0071] (1) Synthesis of component A

[0072] a. NPEF 170 bisphenol F epoxy resin 15 parts, EPALLOY 8240 phenolic epoxy resin 20 parts, neopentyl glycol diglycidyl ether 12 parts are added into a reaction kettle, uniformly stirred at low speed, then SIVO 240 anti-corrosion viscosity reducer 1 part, BYK-1790 defoaming agent 0.8 part, polyamide wax Optima 0.7 part are added, uniformly stirred at medium speed, and a stock solution is obtained;

[0073] b. Titanium dioxide 12 parts, special black 6 carbon black 0.2 parts, quartz powder 10 parts, long mica powder 15 parts, wollastonite 13.3 parts are added into the stock solution, uniformly dispersed at low speed, then dispersed at high speed for 2 hours, the temperature is controlled at 55-60℃ during stirring, and the fineness is controlled to be less than 80um, and the A component is obtained;

[0074] (2) Synthesis of component B

[0075] a. First, 40 moles of cyclohexanediamine are added into a reaction kettle, stirred at a speed of 600 rpm, and heated to 25-35℃ by water bath

[0076] b. 2 moles of N,N,N',N'-tetra(oxymethylene methyl)-1,3-xylylene diamine are diluted with 1 mole of propylene glycol methyl ether, then slowly added into the reaction kettle of step a, the dropping process takes 5.5 hours, then incubated at 25-35℃ for 6 hours, and the stirring speed is kept at 600 rpm and the temperature is controlled at 25-35℃ during the dropping and incubation processes;

[0077] d. 60 parts of the material obtained in step c are taken, N-aminoethylpiperazine 32 parts are added under the condition of heating control temperature of 80-90℃, stirred at a speed of 600 rpm, and cooled to room temperature, then bis(3-triethoxysilyl)propylamine 8 parts are added, uniformly stirred at low speed, and the B component is obtained.

[0078] (3) The A component and the B component are mixed in a mass ratio of 5:1.

[0079] Comparative Example 1

[0080] (1) Synthesis of component A

[0081] a. Add NPEF 170 bisphenol F epoxy resin 40 parts, resorcinol diglycidyl ether 10 parts into a reaction kettle, low speed stirring uniform, then add SIVO 240 anti-corrosion viscosity reducer 0.6 parts, BYK-1790 defoamer 0.6 parts, polyamide wax Optima 0.8 parts, medium speed stirring uniform, get the stock solution;

[0082] b. Add titanium dioxide 15 parts, feldspar powder 15 parts, mica powder 18 parts into the stock solution, low speed dispersion uniform, then dispersion under high speed conditions for 2h, control the temperature at 55-60℃ during stirring, control the fineness less than 80um, get component A;

[0083] (2) Synthesis of component B

[0084] Add Ancamine 2432 curing agent (m-xylylenediamine and epoxy resin adduct) 50 parts into a reaction kettle, add N-aminoethylpiperazine 40 parts under heating control temperature of 80-90℃, stirring uniform at 600 rpm and cooling to room temperature, then add bis(3-triethoxysilyl)propylamine 10 parts, low speed stirring uniform to get component B;

[0085] (3) Mix component A and component B with a mass ratio of 4:1 for use.

[0086] Comparative example 2

[0087] (1) Synthesis of component A

[0088] a. Add EPALLOY 8240 phenolic epoxy resin 30 parts, 1,4-butanediol diglycidyl ether 15 parts, then add SIVO 240 anti-corrosion viscosity reducer 1.5 parts, BYK-1790 defoamer 1 part, polyamide wax Optima 0.5 parts, medium speed stirring uniform, get the stock solution;

[0089] b. Add titanium dioxide 10 parts, special black 6 carbon black 0.5 parts, quartz powder 15 parts, feldspar powder 12 parts, mica powder 14.5 parts into the stock solution, low speed dispersion uniform, then dispersion under high speed conditions for 2h, control the temperature at 55-60℃ during stirring, control the fineness less than 80um, get component A;

[0090] (2) Synthesis of component B

[0091] Add Ancamine 1618 curing agent (isophorone diamine and epoxy resin adduct) 50 parts into a reaction kettle, add N-aminoethylpiperazine 40 parts under heating control temperature of 80-90℃, stirring uniform at 600 rpm and cooling to room temperature, then add bis(3-triethoxysilyl)propylamine 10 parts, low speed stirring uniform to get component B;

[0092] (3) The A component and the B component are mixed in a mass ratio of 6:1.

[0093] Comparative Example 3

[0094] (1) Synthesis of component A

[0095] a. 30 parts of EPALLOY 8240 phenolic epoxy resin, 15 parts of 1,4-butanediol diglycidyl ether, then 1.5 parts of SIVO 240 preservative viscosity reducer, 1 part of BYK-1790 defoaming agent, 0.5 parts of polyamide wax Optima are uniformly stirred at medium speed to obtain a stock solution;

[0096] b. 10 parts of titanium white, 0.5 parts of special black 6 carbon black, 15 parts of quartz powder, 12 parts of feldspar powder, 14.5 parts of mica powder are added to the stock solution and uniformly dispersed at low speed, then dispersed at high speed for 2 h, the temperature is controlled at 55-60°C during stirring, and the fineness is controlled to be less than 80 um to obtain the A component;

[0097] (2) Synthesis of component B

[0098] In the reaction kettle, 90 parts of isophorone diamine and N,N,N',N'-tetra(oxirane methyl)-1,3-benzene diamine adduct (synthesized in the same way as in Example 2) are added, stirred uniformly at 600 rpm and cooled to room temperature, then 10 parts of bis(3-triethoxysilyl)propylamine are uniformly stirred at low speed to obtain the B component;

[0099] (3) The A component and the B component are mixed in a mass ratio of 4:1.

[0100] Comparative Example 4

[0101] (1) Synthesis of component A

[0102] a. 15 parts of NPEF 170 bisphenol F epoxy resin, 20 parts of EPALLOY 8240 phenolic epoxy resin, 12 parts of neopentyl glycol diglycidyl ether are added, then 1 part of SIVO 240 preservative viscosity reducer, 0.8 parts of BYK-1790 defoaming agent, 0.7 parts of polyamide wax Optima are uniformly stirred at medium speed to obtain a stock solution;

[0103] b. 12 parts of titanium white, 0.2 parts of special black 6 carbon black, 10 parts of quartz powder, 15 parts of long mica powder, 13.3 parts of wollastonite are added to the stock solution and uniformly dispersed at low speed, then dispersed at high speed for 2 h, the temperature is controlled at 55-60°C during stirring, and the fineness is controlled to be less than 80 um to obtain the A component;

[0104] (2) Synthesis of component B

[0105] In a reaction kettle, 60 parts of cyclohexanediamine N,N,N',N'-tetra(oxirane-methyl)-1,3-benzene dimethylamine adduct (prepared in the same way as in Example 3) was added, 32 parts of N-aminoethylpiperazine was added under the condition of heating and temperature control at 80-90°C, stirred uniformly at 600 rpm and cooled to room temperature, then 8 parts of γ-aminoethylaminopropyltrimethoxysilane was added and stirred uniformly at low speed to obtain the B component;

[0106] (3) The A component and the B component are mixed in a mass ratio of 5:1.

[0107] In the present case, the high-temperature cathodic disbondment resistance of the high-temperature cathodic disbondment-resistant solvent-free paint prepared by using the scheme of the present application (Examples 1-3) and Comparative Examples 1-4 was investigated. The substrate was a 3 mm sandblasted steel plate, the high-temperature cathodic disbondment-resistant solvent-free paint was sprayed, two different film thicknesses were designed, 500 um and 1000 um, respectively, after drying and curing at room temperature for 7 days, the sample plate was edge-protected, the high-temperature cathodic disbondment resistance was tested according to the standard "ASTM G42-2011 Cathodic Disbondment Test Method for Pipeline Coatings under High Temperature Conditions", the test temperature was set to 95°C, the test time was 30 days, after the test was completed, the coating was peeled off, the peeling radius was measured, and the results are shown in Table 1 below.

[0108] Table 1 High-temperature cathodic disbondment test results of different high-temperature cathodic disbondment-resistant solvent-free paints

[0109]

[0110]

[0111] As can be seen from Table 1, after 30 days of testing at 95°C high temperature, the high-temperature cathodic disbondment-resistant solvent-free paint prepared by Example 1-3 has a significantly smaller peeling radius compared with Comparative Example 1-4, thus has excellent high-temperature cathodic disbondment resistance. This is mainly due to the use of a special added amine curing agent, which improves the active hydrogen functionality of the curing agent; at the same time, a large amount of nitrogen-containing structure is introduced, which greatly improves the wet adhesion and alkali resistance of the coating on the substrate; in addition, the use of bisilane as an adhesion promoter ensures that the bisilane can quickly migrate to the substrate interface and undergo "hydrolysis-polycondensation" with the hydroxyl groups on the substrate interface, improving the wet adhesion; finally, the use of N-aminoethylpiperazine containing tertiary amine as a high-temperature curing promoter ensures that anionic polymerization occurs during the high-temperature cathodic disbondment test to promote rapid curing, further improving the glass transition temperature of the paint film and further improving the high-temperature cathodic disbondment resistance of the paint film. Therefore, the high-temperature cathodic disbondment-resistant solvent-free paint of the present application has excellent high-temperature cathodic disbondment resistance, meeting the demand for the combined use of organic coatings and cathodic protection in deep-sea high-temperature environments.

[0112] The above is the embodiment according to the present application, through the above description, the relevant staff can make various changes and modifications without deviating from the scope of the present application. The technical scope of the present application is not limited to the content of the specification, and must be determined according to the scope of claims.

Claims

1. A high-temperature anti-cathode stripping solvent-free coating, characterized in that, The coating is composed of two components, A and B, wherein component A consists of the following components in parts by weight: 30-40 parts epoxy resin; 10-15 parts of reactive diluent; 0.5–1.5 parts of anti-corrosion and viscosity-reducing agent; 0.5 to 1 part of silicone defoamer; 0.5 to 1 part of polyamide wax thixotropic agent; 10-20 parts of pigment; 20-45 parts of filler; Component B consists of the following components in parts by weight: 50-70 parts of amine adduct; 20-40 parts of N-aminoethylpiperazine; 5-10 parts of adhesion promoter; The weight ratio of A to B is (3-6):

1. In component B, the adhesion promoter is any one or a combination of two of bis(3-triethoxysilyl)propylamine and bis(3-trimethoxysilyl)propylamine. In component B, the amine adduct is an adduct of a dicycloaliphatic amine or an aryl amine with N,N,N',N'-tetra(epoxyethylenemethyl)-1,3-phenylenediamine, wherein the dicycloaliphatic amine is any one or a combination of two or more of 1,3-cyclohexanedimethylamine, cyclohexanediamine or isophoronediamine, and the aryl amine is m-phenylenediamine.

2. The high-temperature anti-cathode stripping solvent-free coating according to claim 1, characterized in that, The epoxy resin component A is any one or a combination of two of bisphenol F epoxy resin and phenolic epoxy resin.

3. The high-temperature anti-cathode stripping solvent-free coating according to claim 1, characterized in that, The epoxy resin component A has a functionality of 2.1-2.

4.

4. The high-temperature anti-cathode stripping solvent-free coating according to claim 1, characterized in that, The active diluent in component A is a bifunctional glycidyl ether diluent.

5. The high-temperature anti-cathode stripping solvent-free coating according to claim 1, characterized in that, The corrosion inhibitor and viscosity reducer is a functional silane dispersant, and the functional silane dispersant is Evonik SIVO 240.

6. The high-temperature anti-cathode stripping solvent-free coating according to claim 1, characterized in that, The pigment is any one or a combination of two of rutile titanium dioxide and carbon black.

7. The high-temperature anti-cathode stripping solvent-free coating according to claim 1, characterized in that, The filler is any two or more of the following: quartz powder, feldspar powder, wollastonite, and mica powder.

8. A method for preparing a high-temperature anti-cathode stripping solvent-free coating as described in any one of claims 1 to 7, characterized in that, Includes the following steps: (1) Synthesis of component A a. Add epoxy resin and reactive diluent, stir at low speed until uniform, then add anti-corrosion and viscosity reducer, defoamer and polyamide wax thixotropic agent, stir at medium speed until uniform to obtain stock solution; b. Add pigments and fillers to the stock solution, disperse evenly at low speed, and then disperse at high speed for 1.5-2 hours. During the stirring process, control the temperature at 55-60℃ and the fineness at less than 80μm to obtain component A. (2) Synthesis of component B a. First, add 30-40 moles of diamine to the reactor and stir at 600-800 rpm while maintaining the temperature at 25-35°C using a water bath. b. Dilute 1.5–2 mol of N,N,N',N'-tetra(epoxyethylenemethyl)-1,3-phenylenediamine with 1 mol of propylene glycol methyl ether and add it dropwise to the reaction vessel of step a over 5–6 hours. Then, maintain the temperature at 25–35°C for 5–6 hours. During the dropwise addition and temperature maintenance, keep the stirring speed at 600–800 rpm and control the temperature at 25–35°C. c. Heat the material obtained in step b to 180-200°C and distill it under a vacuum of at least 740 mmHg. First, distill off the propylene glycol methyl ether solvent, and then distill off the unreacted diamine. d. Take 50-70 parts by weight of the material obtained in step c, heat it at a controlled temperature of 80-90℃, add 20-40 parts of N-aminoethylpiperazine, stir at low speed until uniform, cool to room temperature, add 5-10 parts of adhesion promoter, stir at low speed until uniformly dispersed, to obtain component B. (3) When using, mix component A and component B at a ratio of (3 to 6):1.

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