Deep-sea pressure-resistant self-stratification solventless coating and preparation method thereof

Abstract

The invention discloses a deep-sea pressure-resistant self-stratification solventless coating and a preparation method thereof. The coating comprises a component A and a component B in a mass ratio of (4-6): 1, wherein the component A and the component B are matched with each other; the component A is prepared from epoxy resin, a reactive diluent, a solvent-free hyperdispersant, an anti-corrosion viscosity reducer, an organic silicon defoaming agent, a polyamide wax thixotropic agent, polytetrafluoroethylene powder, hydrophobic nano silicon dioxide, pigment and filler; the component B comprises an alicyclic amine curing agent, polyethyleneimine, long-carbon-chain aliphatic amine and an adhesion promoter. According to the coating disclosed by the invention, through a self-layering effect, excellent wet adhesive force and hydrophobicity of a coating are considered; the problems that a traditional solvent-free coating is high in hydrophilicity of a coating paint film due to high crosslinking density and high polarity and the permeation and diffusion rate of water molecules in the paint film under the high-pressure condition is high are solved, and meanwhile the problem that a common solvent-free coating is used in the deep sea environment and causes permeable foaming due to wet adhesive force is solved. The long-acting anti-corrosion requirement in a deep sea high-pressure environment is met.

Description

Technical Field

[0001] The invention relates to the field of chemical coatings, and in particular to a deep-sea pressure-resistant self-stratified solvent-free coating and a preparation method thereof. Background Art

[0002] With the continuous development of deepwater oil and gas field in the offshore oil and gas field, the research on the corrosion and protection of metal materials in deep-sea environment is imminent. Deep sea generally refers to the marine environment with a water depth of less than 2000m. Compared with shallow sea, the pressure, temperature, dissolved oxygen, etc. of deep-sea environment have undergone significant changes. For example, with the increase of seawater depth, the hydrostatic pressure of seawater increases, and the dissolved oxygen content decreases first and then increases, reaching the lowest at about 1000m, and the temperature gradually decreases. Below 1000m, the seawater temperature is constant at around 0℃. These factors are mixed to form a deep-sea corrosion environment with high pressure, low temperature and low dissolved oxygen content. In the deep-sea corrosion environment, the coating is subjected to the alternating load of hydrostatic pressure. The continuous "push-pull" action will cause cracking at the "coating-interface", reducing the adhesion between the coating and the substrate, which is one of the important reasons for the failure of the coating. At the same time, the high permeability of water in the deep-sea environment will also increase the diffusion rate of water molecules in the coating, increase the water absorption of the coating, cause the coating to lose adhesion, and produce blistering, shedding and other failure problems. The characteristics of deep-sea corrosion environment lead to the accelerated destruction of traditional organic coatings in deep-sea environment, which affects the protective performance of coatings and greatly shortens the protective life of traditional organic coatings. Therefore, it is necessary to develop a deep-sea pressure-resistant coating with excellent long-term anti-corrosion performance for related equipment and facilities in deep-sea environment. Summary of the invention

[0003] In order to solve the above technical problems, the present invention provides a deep-sea pressure-resistant self-stratified solvent-free coating and a preparation method thereof. The coating has excellent deep-sea pressure-resistant and anti-corrosion properties and meets the long-term anti-corrosion requirements under deep-sea environmental conditions.

[0004] In a first aspect, the present invention provides a deep-sea pressure-resistant self-stratifying solvent-free coating, which is achieved by adopting the following technical scheme.

[0005] A deep-sea pressure-resistant self-stratified solvent-free coating, comprising two components, A and B, wherein the weight ratio of component A to component B is (4-6):1;

[0006] Component A includes the following components by weight: 30-40 parts of epoxy resin; 10-15 parts of type A active diluent; 10-15 parts of type B active diluent; 1-1.5 parts of solvent-free hyperdispersant; 0.5-1.5 parts of anticorrosive viscosity reducer; 0.5-1 parts of silicone defoamer; 0.5-1 parts of polyamide wax thixotropic agent; 0.5-1 parts of polytetrafluoroethylene powder; 0.5-1 parts of hydrophobic nano-silicon dioxide; 10-20 parts of pigment; 10-20 parts of filler;

[0007] Component B comprises the following components by weight: 50 to 70 parts of alicyclic amine curing agent; 5 to 10 parts of polyethylene imine; 5 to 10 parts of long carbon chain fatty amine; and 3 to 5 parts of adhesion promoter.

[0008] Furthermore, in component A, the epoxy resin is selected from any one of bisphenol F epoxy resin and novolac epoxy resin or a combination of the two.

[0009] Furthermore, in component A, the functionality of the epoxy resin is 2.1-2.4.

[0010] Furthermore, in component A, the type A reactive diluent is selected from a trifunctional glycidyl ether, a tetrafunctional glycidyl ether or a combination of two thereof. Specifically, the trifunctional glycidyl ether is trimethylolethane triglycidyl ether, and the tetrafunctional glycidyl ether is pentaerythritol glycidyl ether.

[0011] Furthermore, in component A, the type B active diluent is selected to be a composition of one or two of the monofunctional glycidyl ethers with 8 or more long carbon chains. Specifically, the monofunctional glycidyl ethers with 8 or more long carbon chains include C8-10 alkyl glycidyl ether and C12-14 alkyl glycidyl ether.

[0012] Furthermore, in component A, the anti-corrosion and viscosity reducing agent is a functional silane dispersant, and specifically, the functional silane dispersant is SIVO 240 produced by Evonik.

[0013] Furthermore, in component A, the pigment is selected from any one of rutile titanium dioxide and carbon black or a combination of the two.

[0014] Furthermore, in component A, the filler is a combination of any two or more of silicon micropowder, feldspar powder and mica powder.

[0015] Furthermore, in component B, the alicyclic amine curing agent is selected from any one of 1,3-cyclohexanedimethylamine, cyclohexanediamine, isophoronediamine, 4,4'-diaminodicyclohexylmethane, and modified products of polycyclic alicyclic amines, or a combination of two or more thereof.

[0016] Furthermore, in component B, the polyethyleneimine is selected from any one or a combination of polyethyleneimines having a molecular weight of 300-600.

[0017] Furthermore, in component B, the long carbon chain fatty amine is selected from one or a combination of aliphatic diamines having a long carbon chain of 6-9 carbon atoms. Specifically, the aliphatic diamines having a long carbon chain of 6-9 carbon atoms include trimethylhexamethylenediamine and 2-methyl-1,5-pentanediamine.

[0018] Furthermore, in component B, the adhesion promoter is selected from any one of bis(3-triethoxysilyl)propylamine and bis(3-trimethoxysilyl)propylamine, or a combination of the two.

[0019] In a second aspect, the present invention provides a method for preparing a deep-sea pressure-resistant self-stratifying solvent-free coating, which is achieved by adopting the following technical scheme.

[0020] A method for preparing the above-mentioned deep-sea pressure-resistant self-stratifying solvent-free coating comprises the following steps:

[0021] Preparation of S1.A component

[0022] ⅰ The epoxy resin, A-type reactive diluent was mixed, stirred and dispersed evenly at 800-1200rpm, and then the anticorrosive viscosity reducer, silicone defoamer, polyamide wax thixotropic agent was added, stirred and dispersed evenly at 1200-18000rpm to obtain a mixed solution ⅰ;

[0023] ⅱ. Add pigment and filler to the mixed solution ⅰ, stir and disperse evenly at 1200-18000rpm, control the temperature at 55-60 ℃ during the dispersion process, control the fineness to less than 80um, and obtain a mixed solution ⅱ;

[0024] ⅲ. Add a solvent-free hyperdispersant to the B-type reactive diluent, stir and disperse evenly at 600-800rpm, then add polytetrafluoroethylene powder, hydrophobic nano-silica, stir and disperse evenly at 1200-2000rpm to obtain a mixture ⅲ;

[0025] ⅳ. The mixed solution ⅱ and the mixed solution ⅲ were mixed and stirred at 800-1200rpm to obtain component A;

[0026] Preparation of S2.B component

[0027] Mix the alicyclic amine curing agent, polyethyleneimine and long-chain fatty amine, stir and disperse them evenly at 800-1200 rpm, then add the adhesion promoter, stir and disperse them evenly at 600-1000 rpm to obtain component B;

[0028] S3. When using, mix component A and component B in the ratio of (4-6):1.

[0029] This application has the following beneficial effects.

[0030] The present invention provides a pressure-resistant self-stratified solvent-free coating applicable to deep-sea environments. The solvent-free coating produces a self-stratification effect during the curing process after coating construction. The final cured paint film has a stronger polarity in the bottom layer in contact with the substrate, ensuring excellent wet adhesion between the coating and the substrate, avoiding the failure of the coating such as blistering due to water penetrating into the "coating-substrate" interface under the high pressure of the deep sea; at the same time, the paint film cured on the surface has a lower polarity and better hydrophobicity, providing an excellent shielding effect, greatly reducing the diffusion rate of water molecules penetrating into the coating film. In addition, the coating in the middle part of the cured paint film has a higher cross-linking density and curing strength, ensuring the excellent physical and mechanical properties of the coating under high pressure conditions.

[0031] The self-stratified solvent-free coating of the present invention realizes microphase stratification in the curing process after coating construction by the difference in polarity and surface tension of the active diluent and amine curing agent in the coating formula. After the coating components A and B are mixed and coated, during the curing process, the trifunctional glycidyl ether, tetrafunctional glycidyl ether and polyethyleneimine with high polarity and high surface tension migrate to the surface of the substrate and solidify more, and the large amount of ether bond structures in the trifunctional glycidyl ether and tetrafunctional glycidyl ether and the network tertiary amine structure in the polyethyleneimine provide excellent adsorption effect on the substrate, ensuring excellent adhesion between the coating and the substrate, especially ensuring that the coating is not replaced by water molecules when water molecules reach the "coating-substrate" interface, maintaining excellent wet adhesion. At the same time, the monofunctional glycidyl ethers with 8 or more carbon atoms and aliphatic diamines with 6-8 carbon atoms in the coating have lower surface tension and polarity, migrate to the surface and cross-link during curing, and the resulting surface paint film has excellent hydrophobicity due to its low polarity and low content of hydrophilic groups; in addition, polytetrafluoroethylene powder and nano-silica with hydrophobic properties migrate to the coating surface together through the stabilization effect, further improving the hydrophobicity of the cured coating. The phenolic epoxy resin and modified alicyclic amine curing agent in the self-stratified solvent-free coating are enriched in the middle of the coating, giving the cured paint film a high cross-linking density and coating strength, ensuring that the physical and mechanical properties of the coating meet the requirements of deep-sea high-pressure resistance.

[0032] Compared with traditional solvent-free coatings used in deep-sea high-pressure resistant environments, the solvent-free self-stratifying coating of the present invention takes into account both excellent wet adhesion and hydrophobicity of the coating through the self-stratification effect; it avoids the problems of strong hydrophilicity of the coating film due to high cross-linking density and high polarity of traditional solvent-free coatings, and high penetration and diffusion rate of water molecules in the coating film under high-pressure conditions; at the same time, it avoids the permeability blistering problem caused by wet adhesion of common solvent-free coatings in deep-sea environments, and meets the long-term anti-corrosion needs in deep-sea environments. DETAILED DESCRIPTION

[0033] The present patent application is further described below in conjunction with embodiments.

[0034] The materials used in the preparation process of the following examples were not further processed unless otherwise specified and were purchased from commercial sources.

[0035] Example 1

[0036] A method for preparing a deep-sea pressure-resistant self-stratifying solvent-free coating comprises the following steps:

[0037] (1) Preparation of component A

[0038] (i) adding 30 g NPEF170 bisphenol F epoxy resin and 15 g pentaerythritol glycidyl ether, stirring at 1000 rpm for 20 min, then adding 1.5 g SIVO240 anticorrosive viscosity reducer, 0.5 g BYK-1799 silicone defoamer, and 0.5 g polyamide wax Opitma, stirring at 1500 rpm for 45 min, to obtain the mixture of step i;

[0039] (ii) adding 18 g titanium dioxide R-258, 0.1 g super black 6 carbon black, 10 g mica powder, 5 g silica powder, and 4 g feldspar powder to the mixture of step i, and stirring at 1500 rpm for 45 min to obtain the mixture of step ii;

[0040] (iii) adding 14 g of C8-10 alkyl glycidyl ether and 1 g of BYK 2155 solvent-free hyperdispersant, stirring at 600 rpm for 20 min, adding 0.5 g of polytetrafluoroethylene powder and 1 g of hydrophobic nano-silica, stirring at 1500 rpm for 45 min, to obtain the mixture of step iii;

[0041] (iv) Mix the mixture from step ii and the mixed solution from step iii, and stir at 1000 rpm for 45 min to obtain component A.

[0042] (2) Preparation of component B

[0043] (i) 10 g of polyethyleneimine SP-006, 55 g of alicyclic amine curing agent Ancmaine 2280, and 10 g of trimethylhexamethylenediamine were added, and stirred at 1000 rpm for 15 min. Then, 3 g of bis(3-trimethoxysilyl)propylamine was added, and stirred at 800 rpm for 15 min to obtain component B.

[0044] (3) Mix component A and component B in a mass ratio of 4:1.

[0045] Example 2

[0046] A method for preparing a deep-sea pressure-resistant self-stratifying solvent-free coating comprises the following steps:

[0047] (1) Preparation of component A

[0048] (i) adding 35 g EPALLOY8240 phenolic epoxy resin and 15 g trimethylolethane triglycidyl ether, stirring at 800 rpm for 30 min, then adding 1.2 g SIVO240 anticorrosive viscosity reducer, 0.8 g BYK-1799 silicone defoamer, and 0.7 g polyamide wax Opitma, stirring at 1200 rpm for 60 min, to obtain the mixture of step i;

[0049] (ii) adding 15 g titanium dioxide R-258, 0.3 g super black 6 carbon black, 8 g mica powder, 4 g silica powder, and 4 g feldspar powder to the mixture in step i, and stirring at 1200 rpm for 60 min to obtain a mixture in step ii;

[0050] (iii) adding 6 g of C8-10 alkyl glycidyl ether, 6 g of C12-14 alkyl glycidyl ether, and 1.2 g of BYK 2155 solvent-free hyperdispersant, stirring at 800 rpm for 10 min, adding 1 g of polytetrafluoroethylene powder and 0.5 g of hydrophobic nano-silica, and stirring at 2000 rpm for 30 min to obtain the mixture of step iii;

[0051] (iv) The mixture from step ii was mixed with the mixed solution from step iii, and stirred at 800 rpm for 60 min to obtain component A.

[0052] (2) Preparation of component B

[0053] (i) Add 4 g of polyethyleneimine SP-006, 4 g of polyethyleneimine SP-003, 60 g of alicyclic amine curing agent Ancmaine 2280, and 6 g of trimethylhexamethylenediamine, and stir at 800 rpm for 20 min. Then add 2 g of bis(3-trimethoxysilyl)propylamine and 2 g of bis(3-triethoxysilyl)propylamine, and stir at 600 rpm for 20 min to obtain component B.

[0054] (3) Mix component A and component B in a mass ratio of 6:1.

[0055] Example 3

[0056] A method for preparing a deep-sea pressure-resistant self-stratifying solvent-free coating comprises the following steps:

[0057] (1) Preparation of component A

[0058] (i) adding 20 g NPEF170 bisphenol F epoxy resin, 20 g EPALLOY8240 novolac epoxy resin, 6 g pentaerythritol glycidyl ether, and 6 g trimethylolethane triglycidyl ether, stirring at 1200 rpm for 15 min, then adding 0.8 g SIVO240 anticorrosive viscosity reducer, 1 g BYK-1799 silicone defoamer, and 1 g polyamide wax Opitma, stirring at 1800 rpm for 30 min, to obtain the mixture of step i;

[0059] (ii) adding 10 g titanium dioxide R-258, 0.5 g super black 6 carbon black, 6 g mica powder, 6 g silica powder, and 6 g feldspar powder to the mixture in step i, and stirring at 1800 rpm for 30 min to obtain the mixture in step ii;

[0060] (iii) adding 10 g of C12-14 alkyl glycidyl ether and 1.5 g of BYK 2155 solvent-free hyperdispersant, stirring at 700 rpm for 15 min, adding 0.6 g of polytetrafluoroethylene powder and 0.6 g of hydrophobic nano-silica, stirring at 1200 rpm for 60 min, to obtain the mixture of step iii;

[0061] (iv) Mix the mixture from step ii and the mixed solution from step iii, and stir at 1200 rpm for 30 min to obtain component A.

[0062] (2) Preparation of component B

[0063] (i) 5 g of polyethyleneimine SP-003, 65 g of alicyclic amine curing agent Ancmaine 2280 and 5 g of trimethylhexamethylenediamine were added, and stirred at 1200 rpm for 10 min. Then, 5 g of bis(3-triethoxysilyl)propylamine was added, and stirred at 1000 rpm for 10 min to obtain component B.

[0064] (3) Mix component A and component B in a mass ratio of 5:1.

[0065] Comparative Example 1

[0066] A method for preparing a coating comprises the following steps:

[0067] (1) Preparation of component A

[0068] (i) adding 30 g NPEF170 bisphenol F epoxy resin and 15 g pentaerythritol glycidyl ether, stirring at 1000 rpm for 20 min, then adding 1.5 g SIVO240 anticorrosive viscosity reducer, 0.5 g BYK-1799 silicone defoamer, and 0.5 g polyamide wax Opitma, stirring at 1500 rpm for 45 min, to obtain the mixture of step i;

[0069] (ii) adding 18 g titanium dioxide R-258, 0.1 g super black 6 carbon black, 10 g mica powder, 5 g silica powder, and 4 g feldspar powder to the mixture of step i, and stirring at 1500 rpm for 45 min to obtain the mixture of step ii;

[0070] (iii) adding 14 g of pentaerythritol glycidyl ether and 1 g of BYK 2155 solvent-free hyperdispersant, stirring at 600 rpm for 20 min, adding 0.5 g of polytetrafluoroethylene powder and 1 g of hydrophobic nano-silica, stirring at 1500 rpm for 45 min, to obtain the mixture of step iii;

[0071] (iv) Mix the mixture from step ii and the mixed solution from step iii, and stir at 1000 rpm for 45 min to obtain component A.

[0072] (2) Preparation of component B

[0073] (i) 10 g of polyethyleneimine SP-006, 55 g of alicyclic amine curing agent Ancmaine 2280, and 10 g of trimethylhexamethylenediamine were added, and stirred at 1000 rpm for 15 min. Then, 3 g of bis(3-trimethoxysilyl)propylamine was added, and stirred at 800 rpm for 15 min to obtain component B.

[0074] (3) Mix component A and component B in a mass ratio of 4:1.

[0075] Comparative Example 2

[0076] A method for preparing a coating comprises the following steps:

[0077] (1) Preparation of component A

[0078] (i) adding 35 g EPALLOY8240 phenolic epoxy resin, 7.5 g C8-10 alkyl glycidyl ether, and 7.5 g C12-14 alkyl glycidyl ether, stirring at 800 rpm for 30 min, then adding 1.2 g SIVO240 anticorrosive viscosity reducer, 0.8 g BYK-1799 silicone defoamer, and 0.7 g polyamide wax Opitma, stirring at 1200 rpm for 60 min, to obtain the mixture of step i;

[0079] (ii) adding 15 g titanium dioxide R-258, 0.3 g super black 6 carbon black, 8 g mica powder, 4 g silica powder, and 4 g feldspar powder to the mixture in step i, and stirring at 1200 rpm for 60 min to obtain a mixture in step ii;

[0080] (iii) adding 6 g of C8-10 alkyl glycidyl ether, 6 g of C12-14 alkyl glycidyl ether, and 1.2 g of BYK 2155 solvent-free hyperdispersant, stirring at 800 rpm for 10 min, adding 1 g of polytetrafluoroethylene powder and 0.5 g of hydrophobic nano-silica, and stirring at 2000 rpm for 30 min to obtain the mixture of step iii;

[0081] (iv) The mixture from step ii was mixed with the mixed solution from step iii, and stirred at 800 rpm for 60 min to obtain component A.

[0082] (2) Preparation of component B

[0083] (i) Add 4 g of polyethyleneimine SP-006, 4 g of polyethyleneimine SP-003, 60 g of alicyclic amine curing agent Ancmaine 2280, and 6 g of trimethylhexamethylenediamine, and stir at 800 rpm for 20 min. Then add 2 g of bis(3-trimethoxysilyl)propylamine and 2 g of bis(3-triethoxysilyl)propylamine, and stir at 600 rpm for 20 min to obtain component B.

[0084] (3) Mix component A and component B in a mass ratio of 6:1.

[0085] Comparative Example 3

[0086] A method for preparing a coating comprises the following steps:

[0087] (1) Preparation of component A

[0088] (i) adding 20 g NPEF170 bisphenol F epoxy resin, 20 g EPALLOY8240 novolac epoxy resin, 6 g pentaerythritol glycidyl ether, and 6 g trimethylolethane triglycidyl ether, stirring at 1200 rpm for 15 min, then adding 0.8 g SIVO240 anticorrosive viscosity reducer, 1 g BYK-1799 silicone defoamer, and 1 g polyamide wax Opitma, stirring at 1800 rpm for 30 min, to obtain the mixture of step i;

[0089] (ii) adding 10 g titanium dioxide R-258, 0.5 g super black 6 carbon black, 6 g mica powder, 6 g silica powder, and 6 g feldspar powder to the mixture in step i, and stirring at 1800 rpm for 30 min to obtain the mixture in step ii;

[0090] (iii) adding 10 g of C12-14 alkyl glycidyl ether and 1.5 g of BYK 2155 solvent-free hyperdispersant, stirring at 700 rpm for 15 min, adding 0.6 g of polytetrafluoroethylene powder and 0.6 g of hydrophobic nano-silica, stirring at 1200 rpm for 60 min, to obtain the mixture of step iii;

[0091] (iv) Mix the mixture from step ii and the mixed solution from step iii, and stir at 1200 rpm for 30 min to obtain component A.

[0092] (2) Preparation of component B

[0093] (i) 10 g of polyethyleneimine SP-003 and 65 g of alicyclic amine curing agent Ancmaine 2280 were added, stirred at 1200 rpm for 10 min, and then 5 g of bis(3-triethoxysilyl)propylamine was added, and stirred at 1000 rpm for 10 min to obtain component B.

[0094] (3) Mix component A and component B in a mass ratio of 5:1.

[0095] Comparative Example 4

[0096] A method for preparing a coating comprises the following steps:

[0097] (1) Preparation of component A

[0098] (i) adding 20 g EPALLOY8240 phenolic epoxy resin, 20 g NPEF170 bisphenol F epoxy resin, 6 g pentaerythritol glycidyl ether, and 6 g trimethylolethane triglycidyl ether, stirring at 1200 rpm for 15 min, then adding 0.8 g SIVO240 anticorrosive viscosity reducer, 1 g BYK-1799 silicone defoamer, and 1 g polyamide wax Opitma, stirring at 1800 rpm for 30 min, to obtain the mixture of step i;

[0099] (ii) adding 10 g titanium dioxide R-258, 0.5 g super black 6 carbon black, 6 g mica powder, 6 g silica powder, and 6 g feldspar powder to the mixture in step i, and stirring at 1800 rpm for 30 min to obtain the mixture in step ii;

[0100] (iii) adding 10 g of C12-14 alkyl glycidyl ether and 1.5 g of BYK 2155 solvent-free hyperdispersant, stirring at 700 rpm for 15 min, adding 0.6 g of polytetrafluoroethylene powder and 0.6 g of hydrophobic nano-silica, stirring at 1200 rpm for 60 min, to obtain the mixture of step iii;

[0101] (iv) Mix the mixture from step ii and the mixed solution from step iii, and stir at 1200 rpm for 30 min to obtain component A.

[0102] (2) Preparation of component B

[0103] (i) 65 g of alicyclic amine curing agent Ancmaine 2280 and 10 g of trimethylhexamethylenediamine were added, and the mixture was stirred at 1200 rpm for 10 min. Then, 5 g of bis(3-triethoxysilyl)propylamine was added, and the mixture was stirred at 1000 rpm for 10 min to obtain component B.

[0104] (3) Mix component A and component B in a mass ratio of 6:1.

[0105] Performance Testing

[0106] This application tests the high-pressure salt water immersion resistance and cathodic stripping resistance of deep-sea pressure-resistant self-layering solvent-free coatings (Examples 1-3) and comparative examples 1-4 prepared by the scheme of the present invention. The substrate is a 3mm sandblasted steel plate, sprayed with a deep-sea pressure-resistant self-layering solvent-free coating, with a designed film thickness of 400μm. After drying and curing at room temperature for 7 days, the sample is edge-sealed for protection, and then tested for high-pressure salt water immersion resistance according to the standard "NACE TM0185-2024 Evaluation of the anti-corrosion effect of plastic coatings in pipes by autoclave test"; at the same time, considering that organic coatings used in deep-sea environments are generally used in conjunction with cathodic protection, the deep-sea pressure-resistant self-layering solvent-free coating is tested for cathodic stripping resistance according to method B in "ISO 15711-2003 "Determination of cathodic stripping resistance of coatings of paints and varnishes exposed to seawater". After the test, the coating is stripped and the stripping radius is measured, as shown in Table 1 below.

[0107] Table 1 Test results of high-pressure salt water immersion and cathodic stripping resistance of deep-sea pressure-resistant self-stratified solvent-free coating

[0108]

[0109]

[0110] It can be seen from Table 1 that under the conditions of 20MPa, 3.5% NaCl high-pressure immersion test, the deep-sea pressure-resistant self-stratified solvent-free coatings prepared in Examples 1-3 were tested for 90 days and the coatings were intact without failure problems such as blistering, cracking and falling off; while the comparative examples 1-4 basically showed blistering and rust after 60 days of testing, and the coating failed; at the same time, it can be seen from the anti-cathode stripping test that the deep-sea pressure-resistant self-stratified solvent-free coating of the present invention has a smaller stripping radius than that of comparative examples 1-4, and therefore has excellent anti-cathode stripping performance and good compatibility with cathodic protection. The excellent performance of Examples 1-3 is mainly due to the adoption of the self-stratification design concept. During the curing process of the solvent-free coating, the glycidyl ethers and organic amines with high polarity and high surface tension migrate to the "coating-substrate" interface, and the wet adhesion is improved through the adsorption of polar groups; at the same time, the glycidyl ethers and organic amines with low polarity and surface tension and the polytetrafluoroethylene powder and nano-silica with hydrophobic function migrate to the coating surface, greatly improving the hydrophobicity of the paint film, reducing the diffusion and transmission of water in the paint film, and improving the shielding effect of the paint film. Therefore, through the self-stratification benefit, the technical problem that the high polarity and hydrophobicity of the organic coating under deep-sea high-pressure conditions cannot be taken into account at the same time is solved. In summary, the deep-sea pressure-resistant self-stratified solvent-free coating of the present invention has excellent wet adhesion and hydrophobic shielding properties, which meets the high-pressure immersion and corrosion resistance requirements in the deep-sea field.

[0111] The embodiments of this specific implementation method are all preferred embodiments of the present invention, and are not intended to limit the protection scope of the present invention. Therefore, any equivalent changes made based on the structure, shape, and principle of the present invention should be included in the protection scope of the present invention.

Claims

1. A deep-sea pressure-resistant self-stratifying solvent-free coating, characterized in that: It is composed of two components, A and B, and the weight ratio of component A to component B is (4-6):1; Component A includes the following components by weight: 30-40 parts of epoxy resin; 10-15 parts of type A active diluent; 10-15 parts of type B active diluent; 1-1.5 parts of solvent-free hyperdispersant; 0.5-1.5 parts of anticorrosive viscosity reducer; 0.5-1 parts of silicone defoamer; 0.5-1 parts of polyamide wax thixotropic agent; 0.5-1 parts of polytetrafluoroethylene powder; 0.5-1 parts of hydrophobic nano-silicon dioxide; 10-20 parts of pigment; 10-20 parts of filler; Component B comprises the following components by weight: 50 to 70 parts of alicyclic amine curing agent; 5 to 10 parts of polyethylene imine; 5 to 10 parts of long carbon chain fatty amine; and 3 to 5 parts of adhesion promoter.

2. A deep-sea pressure-resistant self-stratifying solvent-free coating according to claim 1, characterized in that: In component A, the epoxy resin is selected from any one of bisphenol F epoxy resin and novolac epoxy resin or a combination of the two; the functionality of the epoxy resin is 2.1-2.

4.

3. A deep-sea pressure-resistant self-stratifying solvent-free coating according to claim 1, characterized in that: In component A, the type A reactive diluent is selected from one or a combination of trifunctional glycidyl ether and tetrafunctional glycidyl ether.

4. The deep-sea pressure-resistant self-stratifying solvent-free coating according to claim 1, characterized in that: In component A, the type B active diluent is selected from one or a combination of two of the monofunctional glycidyl ethers having 8 or more carbon chains.

5. The deep-sea pressure-resistant self-stratifying solvent-free coating according to claim 1, characterized in that: In component A, the anti-corrosion and viscosity-reducing agent is a functional silane dispersant.

6. The deep-sea pressure-resistant self-stratifying solvent-free coating according to claim 1, characterized in that: In component B, the alicyclic amine curing agent is selected from any one of 1,3-cyclohexanedimethylamine, cyclohexanediamine, isophoronediamine, 4,4'-diaminodicyclohexylmethane, and modified products of polycyclic alicyclic amines, or a combination of two or more thereof.

7. The deep-sea pressure-resistant self-stratifying solvent-free coating according to claim 1, characterized in that: In component B, the polyethyleneimine is selected from any one or a combination of polyethyleneimines with a molecular weight between 300 and 600.

8. The deep-sea pressure-resistant self-stratifying solvent-free coating according to claim 1, characterized in that: In component B, the long carbon chain fatty amine is selected from one or a combination of aliphatic diamines having a long carbon chain of 6 to 9 carbon atoms.

9. The deep-sea pressure-resistant self-stratifying solvent-free coating according to claim 1, characterized in that: In component B, the adhesion promoter is selected from bis(3-triethoxysilyl)propylamine, bis(3-trimethoxysilyl)propylamine or a combination of the two.

10. A method for preparing the deep-sea pressure-resistant self-stratifying solvent-free coating according to any one of claims 1 to 9, characterized in that: The following steps are involved: Preparation of S1.A component ⅰ The epoxy resin, A-type reactive diluent was mixed, stirred and dispersed evenly at 800-1200rpm, and then the anticorrosive viscosity reducer, silicone defoamer, polyamide wax thixotropic agent was added, stirred and dispersed evenly at 1200-18000rpm to obtain a mixed solution ⅰ; ⅱ. Add pigment and filler to the mixed solution ⅰ, stir and disperse evenly at 1200-18000rpm, control the temperature at 55-60 ℃ during the dispersion process, control the fineness to less than 80um, and obtain a mixed solution ⅱ; ⅲ. Add a solvent-free hyperdispersant to the B-type reactive diluent, stir and disperse evenly at 600-800rpm, then add polytetrafluoroethylene powder, hydrophobic nano-silica, stir and disperse evenly at 1200-2000rpm to obtain a mixture ⅲ; ⅳ. The mixed solution ⅱ and the mixed solution ⅲ were mixed and stirred at 800-1200rpm to obtain component A; Preparation of S2.B component Mix the alicyclic amine curing agent, polyethyleneimine and long-chain fatty amine, stir and disperse them evenly at 800-1200 rpm, then add the adhesion promoter, stir and disperse them evenly at 600-1000 rpm to obtain component B; S3. When using, mix component A and component B in the ratio of (4-6):1.

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