High-solid-content low-surface-treatment moisture-curing epoxy resin coating as well as preparation method and application thereof

Abstract

The invention belongs to the technical field of moisture-curing coatings, and provides a high-solid-content low-surface-treatment moisture-curing epoxy resin coating as well as a preparation method and application thereof. The high-solid-content low-surface-treatment moisture-curing epoxy resin coating comprises a component A and a component B in a mass ratio of (6-8): 1, wherein the component A comprises epoxy resin, polyurethane resin, iron oxide red, an anti-rust filler, a rust conversion agent, an anti-settling agent, a defoaming agent, a functional filler, a dispersing agent, a reactive diluent and an organic solvent in specific parts by mass; the component B comprises a modified amine curing agent, a Mannich base curing agent and an organic solvent in specific parts by mass. The low-surface-treatment moisture-curing epoxy resin coating disclosed by the invention is high in drying speed, good in adhesive force, high in solid content and excellent in corrosion resistance; the drying speed is very high no matter in a high-temperature and high-humidity environment or a low-temperature and high-humidity environment, and the paint has good adhesive force, chemical resistance and salt fog resistance on a substrate with a firm rust layer.

Description

Technical Field

[0001] The invention relates to the technical field of moisture-curing coatings, and in particular to a high-solid content, low-surface-treated moisture-curing epoxy resin coating, and a preparation method and application thereof. Background Art

[0002] In recent years, a large number of oil tanks in oil caverns need to be repaired urgently before they can be put into use. Many oil caverns are in low temperature and high humidity or high temperature and high humidity environments for a long time. The long-term humid state makes it impossible to apply general coatings. Moreover, as the service life gradually increases, the coating anti-corrosion layer of the oil tank also fails. The effect of conventional coating protection is not ideal. There is an urgent need for low surface treatment moisture-curing anti-corrosion coatings that can be quickly applied and cured in high humidity environments.

[0003] According to different rust coating mechanisms, rust coatings can be divided into four categories: stable, penetrating, converting and comprehensive. The most commonly used is the comprehensive rust coating that has the functions of rust stabilization, penetration and conversion. The coating components include rust-stabilizing pigments, rust penetrants and converters, and most of the base materials are epoxy resins. However, the rust-stabilizing pigments are mostly chromium pigments, which are highly toxic and not environmentally friendly; the converters are mostly phosphoric acid-tannic acid or phosphoric acid-phytic acid combinations, the dosage is difficult to control, and the acidic substances will damage the resin performance, resulting in a decrease in the anti-corrosion performance of the coating.

[0004] Therefore, it is of great significance to study and obtain a low-surface-treated moisture-curing epoxy resin coating with high solid content, good corrosion resistance, and the ability to dry quickly in a high-humidity environment, which can be used to repair oil tank coatings and extend the life of oil tanks. Summary of the invention

[0005] The purpose of the present invention is to provide a high-solid content, low-surface-treated, moisture-curing epoxy resin coating and a preparation method and application thereof in view of the deficiencies in the prior art.

[0006] In order to achieve the above-mentioned object of the invention, the present invention provides the following technical solutions:

[0007] The present invention provides a high-solid content, low-surface-treatment, moisture-curing epoxy resin coating, comprising component A and component B, wherein the mass ratio of component A to component B is 6 to 8:1;

[0008] The component A comprises the following components in parts by weight: 30-40 parts of epoxy resin, 5-10 parts of polyurethane resin, 10-15 parts of red iron oxide, 10-15 parts of anti-rust filler, 1-3 parts of rust conversion agent, 1-3 parts of anti-settling agent, 0.3-0.5 parts of defoamer, 2-5 parts of functional filler, 0.5-0.8 parts of dispersant, 8-12 parts of active diluent, and 10-15 parts of organic solvent;

[0009] The B component comprises the following components in parts by weight: 40 to 50 parts of a modified amine curing agent, 20 to 25 parts of a Mannich base curing agent, and 20 to 25 parts of an organic solvent.

[0010] Preferably, the epoxy resin is one or more of 128 epoxy resin, E20 epoxy resin and 828 epoxy resin.

[0011] Preferably, the anti-rust filler is zinc phosphate and / or aluminum tripolyphosphate; the rust conversion agent is diphenylguanidine chromate and / or modified epoxy rust-bearing resin.

[0012] Preferably, the anti-settling agent is organic bentonite and / or fumed silica, the defoaming agent is a fluorosilicone-modified polysiloxane defoaming agent; and the functional filler comprises one or more of precipitated barium sulfate, quartz powder and talcum powder.

[0013] Preferably, the active diluent is alkyl glycidyl ether, and the organic solvents in component A and component B are independently one or more of xylene, n-butanol and anhydrous ethanol.

[0014] Preferably, the modified amine curing agent is a cashew nut shell oil modified amine epoxy resin curing agent.

[0015] The present invention also provides a method for preparing the high-solid content, low-surface-treated, moisture-curing epoxy resin coating, comprising the following steps:

[0016] 1) mixing epoxy resin, polyurethane resin, anti-settling agent, defoaming agent and dispersant to obtain a mixture;

[0017] 2) mixing the mixed material, red iron oxide, anti-rust filler, rust conversion agent, functional filler, active diluent and organic solvent and refining the mixture to obtain component A;

[0018] 3) Mixing the modified amine curing agent, the Mannich base curing agent and the organic solvent to obtain component B.

[0019] Preferably, the mixing speed in step 1) is 600-700 r / min, and the mixing time is 5-10 min; the mixing speed in step 2) is 700-900 r / min, and the mixing time is 10-15 min; the mixing speed in step 3) is 500-600 r / min, and the mixing time is 10-15 min.

[0020] The present invention also provides the use of the high-solid content, low-surface-treated, moisture-curing epoxy resin coating in oil tanks.

[0021] The beneficial effects of the present invention include the following:

[0022] 1) The epoxy resin of the present invention has excellent adhesion and chemical corrosion resistance, and the polyurethane resin has excellent wear resistance and flexibility. The epoxy resin and the polyurethane resin are used in combination, which can significantly improve the chemical corrosion resistance of the coating and are suitable for various industrial environments. The cashew nut shell oil modified amine epoxy resin curing agent of the present invention improves the flexibility and hydrophobicity of the curing system, increases the fluidity and permeability of the curing system; the cashew nut shell oil modified amine epoxy resin curing agent and the Mannich base curing agent can penetrate the rusted surface of the substrate well, squeeze out the water, volatilize with the solvent, have good adhesion to the wet surface, are suitable for the coating of the wet curing type with rust surface, and have low production cost.

[0023] 2) The present invention combines epoxy resin, polyurethane resin with red iron oxide, anti-rust filler, rust conversion agent, active diluent, etc. to obtain component A, cashew nut shell oil modified amine epoxy resin curing agent and Mannich base curing agent as component B, and reasonably selects the types of raw materials of component A and component B, and reasonably controls the amount of each component to obtain a low surface treatment moisture-curing epoxy resin coating with fast drying speed, good adhesion, high solid content and excellent corrosion resistance. The epoxy resin coating of the present invention has good drying ability regardless of whether it is under high temperature and high humidity or low temperature and high humidity environment, and the drying speed is very fast. Moreover, it has good adhesion, chemical resistance and salt spray resistance on a substrate with a firm rust layer. DETAILED DESCRIPTION

[0024] The present invention provides a high-solid content, low-surface-treatment, moisture-curing epoxy resin coating, comprising component A and component B, wherein the mass ratio of component A to component B is 6 to 8:1;

[0025] The component A comprises the following components in parts by weight: 30-40 parts of epoxy resin, 5-10 parts of polyurethane resin, 10-15 parts of red iron oxide, 10-15 parts of anti-rust filler, 1-3 parts of rust conversion agent, 1-3 parts of anti-settling agent, 0.3-0.5 parts of defoamer, 2-5 parts of functional filler, 0.5-0.8 parts of dispersant, 8-12 parts of active diluent, and 10-15 parts of organic solvent;

[0026] The B component comprises the following components in parts by weight: 40 to 50 parts of a modified amine curing agent, 20 to 25 parts of a Mannich base curing agent, and 20 to 25 parts of an organic solvent.

[0027] In the present invention, the mass ratio of component A to component B is preferably 6.5 to 7.5:1, more preferably 7:1.

[0028] The A component of the present invention contains 30 to 40 parts of epoxy resin, preferably 32 to 38 parts, more preferably 34 to 36 parts, and even more preferably 35 parts.

[0029] In the present invention, the epoxy resin is preferably one or more of 128 epoxy resin, E20 epoxy resin and 828 epoxy resin.

[0030] The A component of the present invention contains 5 to 10 parts of polyurethane resin, preferably 6 to 9 parts, and more preferably 7 to 8 parts.

[0031] Isocyanate groups have a wide range of uses and can be cured into films under low temperature and high humidity environments: the -NCO in the coating is very active and can undergo cross-linking reactions with hydroxyl components and molecules containing active hydrogen at low temperatures to cure into films; the higher the humidity, the easier it is for the -NCO in the coating to react with moisture in the air to form a film, and the faster the curing speed; the urethane bonds in the coating do not react with acids, alkalis, or oils, and have properties similar to amide groups, with excellent corrosion resistance; active isocyanates can not only react with hydroxyl resins, but also combine with moisture in the air and hydroxyl groups on the substrate to enhance adhesion to the substrate.

[0032] The component A of the present invention contains 10 to 15 parts of red iron oxide, preferably 11 to 14 parts, and more preferably 12 to 13 parts.

[0033] The component A of the present invention contains 10 to 15 parts of antirust filler, preferably 11 to 14 parts, and more preferably 12 to 13 parts; the antirust filler is preferably zinc phosphate and / or aluminum tripolyphosphate.

[0034] In the present invention, the phosphate radical in zinc phosphate can passivate the metal surface, block the ions of ammonium salts from damaging the paint film, form chemical coordination with the hydroxyl and carboxyl groups in the paint, and improve the adhesion and impermeability of the coating. The zinc ions can form cathodic protection on the surface and enhance the salt spray effect. Aluminum tripolyphosphate forms a dense passivation film on the surface of the substrate, which plays a role in stabilizing and preventing rust.

[0035] The component A of the present invention comprises 1 to 3 parts of a rust conversion agent, preferably 1.5 to 2.5 parts, and more preferably 2 parts; the rust conversion agent is preferably diphenylguanidine chromate and / or a modified epoxy rust-bearing resin.

[0036] Diphenylguanidine chromate is a coordination compound of organic nitrogen and chromic acid. It has excellent anti-rust properties when added in small amounts. The groups formed by organic nitrogen after combining with hydrogen are relatively stable, while the chromate group combined with it is unstable and can be ionized in aqueous solution. The ionized stable organic nitrogen ions combined with hydrogen can stably combine with the divalent and trivalent iron in the rust, thereby achieving the effect of rust-resistant construction, while the ionized chromate ions can play a role in corrosion resistance and resistance to salt spray, acid and alkali.

[0037] The component A of the present invention contains 1 to 3 parts of an anti-settling agent, preferably 1.5 to 2.5 parts, and more preferably 2 parts; the anti-settling agent is preferably organic bentonite and / or fumed silica.

[0038] The component A of the present invention contains 0.3 to 0.5 parts of a defoamer, preferably 0.4 parts; the defoamer is preferably a fluorine-silicon modified polysiloxane defoamer.

[0039] The component A of the present invention comprises 2 to 5 parts of functional fillers, preferably 2.5 to 4.5 parts, and more preferably 3 to 4 parts; the functional fillers preferably comprise one or more of precipitated barium sulfate, quartz powder and talcum powder.

[0040] In the present invention, talcum powder can improve the thixotropy and anti-sagging properties of the paint film, while precipitated barium sulfate and quartz powder can improve the hardness of the paint film.

[0041] The component A of the present invention contains 0.5 to 0.8 parts of a dispersant, preferably 0.6 to 0.7 parts; the dispersant is preferably dispersant BYK-110 or YCK-2070.

[0042] The component A of the present invention contains 8 to 12 parts of active diluent, preferably 9 to 11 parts, and more preferably 10 parts; the active diluent is preferably an alkyl glycidyl ether, and more preferably dodecyl glycidyl ether, tridecyl glycidyl ether or tetradecyl glycidyl ether.

[0043] The active diluent of the present invention has good hydrophobicity and low surface tension. When coating on a wet surface, it can drain the moisture on the surface of the substrate, wet the substrate, and ensure good adhesion and anti-corrosion performance.

[0044] The component A of the present invention contains 10 to 15 parts of an organic solvent, preferably 11 to 14 parts, and more preferably 12 to 13 parts.

[0045] The B component of the present invention contains 40 to 50 parts of a modified amine curing agent, preferably 42 to 48 parts, more preferably 44 to 46 parts, and even more preferably 45 parts.

[0046] In the present invention, the modified amine curing agent is preferably a cashew nut shell oil modified amine epoxy resin curing agent.

[0047] The B component of the present invention contains 20 to 25 parts of the Mannich base curing agent, preferably 21 to 24 parts, and more preferably 22 to 23 parts.

[0048] The component B of the present invention contains 20 to 25 parts of an organic solvent, preferably 21 to 24 parts, and more preferably 22 to 23 parts.

[0049] In the present invention, the organic solvents in component A and component B are independently preferably one or more of xylene, n-butanol and anhydrous ethanol.

[0050] The present invention also provides a method for preparing the high-solid content, low-surface-treated, moisture-curing epoxy resin coating, comprising the following steps:

[0051] 1) mixing epoxy resin, polyurethane resin, anti-settling agent, defoaming agent and dispersant to obtain a mixture;

[0052] 2) mixing the mixed material, red iron oxide, anti-rust filler, rust conversion agent, functional filler, active diluent and organic solvent and refining the mixture to obtain component A;

[0053] 3) Mixing the modified amine curing agent, the Mannich base curing agent and the organic solvent to obtain component B.

[0054] In the present invention, the mixing speed in step 1) is preferably 600-700 r / min, more preferably 620-680 r / min, more preferably 640-650 r / min, and the mixing time is preferably 5-10 min, more preferably 6-9 min, more preferably 7-8 min; the mixing speed in step 2) is preferably 700-900 r / min, more preferably 750-850 r / min, more preferably 800 r / min, and the mixing time is preferably 10-15 min, more preferably 11-14 min, more preferably 12-13 min; the mixing speed in step 3) is preferably 500-600 r / min, more preferably 520-580 r / min, more preferably 540-550 r / min, and the mixing time is preferably 10-15 min, more preferably 11-14 min, more preferably 12-13 min.

[0055] The present invention also provides the use of the high-solid content, low-surface-treated, moisture-curing epoxy resin coating in oil tanks.

[0056] The technical solutions provided by the present invention are described in detail below in conjunction with the embodiments, but they should not be construed as limiting the protection scope of the present invention.

[0057] In the embodiments, the parts are all parts by mass; the polyurethane resin is polyurethane resin BZS-605, the organic bentonite is organic bentonite SD-2, the defoamer is defoamer BYK-066N, the dispersant is dispersant BYK-110, and the cashew nut shell oil modified amine epoxy resin curing agent is cashew nut shell oil modified amine epoxy resin curing agent JT-6060.

[0058] Example 1

[0059] The high-solid content, low-surface-treated moisture-curing epoxy resin coating of this embodiment comprises component A and component B in a mass ratio of 7:1;

[0060] 35 parts of 128 epoxy resin, 8 parts of polyurethane resin, 2 parts of organic bentonite, 0.4 parts of defoamer and 0.6 parts of dispersant were mixed at a speed of 650 r / min for 8 minutes to obtain a mixture; 12 parts of red iron oxide, 6 parts of zinc phosphate, 6 parts of aluminum tripolyphosphate, 2 parts of diphenylguanidine chromate, 3 parts of precipitated barium sulfate, 10 parts of tridecyl glycidyl ether, 6 parts of xylene and 6 parts of anhydrous ethanol were added to the mixture, mixed at a speed of 800 r / min for 13 minutes, and ground to obtain component A with a particle size of ≤30 μm;

[0061] 45 parts of cashew nut shell oil-modified amine epoxy resin curing agent, 22 parts of Mannich base curing agent and 23 parts of anhydrous ethanol were mixed at a rotation speed of 550 r / min for 12 minutes to obtain component B.

[0062] Example 2

[0063] The high solid content, low surface treatment, moisture-curing epoxy resin coating of this embodiment comprises component A and component B in a mass ratio of 6.5:1;

[0064] 32 parts of E20 epoxy resin, 9 parts of polyurethane resin, 1.5 parts of organic bentonite, 0.3 parts of defoamer and 0.7 parts of dispersant were mixed at a speed of 620 r / min for 10 minutes to obtain a mixture; 11 parts of red iron oxide, 15 parts of zinc phosphate, 1 part of diphenylguanidine chromate, 2 parts of quartz powder, 9 parts of dodecyl glycidyl ether and 11 parts of anhydrous ethanol were added to the mixture, mixed at a speed of 750 r / min for 15 minutes, and ground to obtain component A with a particle size of ≤35 μm;

[0065] 42 parts of cashew nut shell oil-modified amine epoxy resin curing agent, 25 parts of Mannich base curing agent and 22 parts of xylene were mixed at a rotation speed of 520 r / min for 15 minutes to obtain component B.

[0066] Example 3

[0067] The high solid content, low surface treatment, moisture-curing epoxy resin coating of this embodiment comprises component A and component B in a mass ratio of 7.5:1;

[0068] 38 parts of 828 epoxy resin, 6 parts of polyurethane resin, 2.5 parts of fumed silica, 0.5 parts of defoamer and 0.5 parts of dispersant were mixed at a speed of 700 r / min for 6 minutes to obtain a mixture; 15 parts of red iron oxide, 11 parts of aluminum tripolyphosphate, 13 parts of modified epoxy rust-bearing resin X800-, 4 parts of talcum powder, 11 parts of tetradecyl glycidyl ether and 15 parts of n-butanol were added to the mixture, mixed at a speed of 850 r / min for 11 minutes, and ground to obtain component A with a particle size of ≤40 μm;

[0069] 48 parts of cashew nut shell oil-modified amine epoxy resin curing agent JT-6060, 20 parts of Mannich base curing agent and 24 parts of anhydrous ethanol were mixed at a rotation speed of 600 r / min for 10 minutes to obtain component B.

[0070] Comparative Example 1

[0071] The polyurethane resin and diphenylguanidine chromate of Example 1 were omitted, and the cashew nut shell oil-modified amine epoxy resin curing agent was replaced by a modified polyamide curing agent 6510. Other conditions were the same as those of Example 1.

[0072] Comparative Example 2

[0073] The red iron oxide and tridecyl glycidyl ether of Example 1 were omitted, the Mannich base curing agent was omitted, the mass ratio of component A to component B was changed to 5:1, and the other conditions were the same as those of Example 1.

[0074] When the high solid content, low surface treatment, moisture-curing epoxy resin coating of the embodiment and comparative example 1 is used, component A and component B are mixed evenly and aged at room temperature for 20 minutes, and then coated on an iron metal substrate with a rust layer thickness of 45 μm, and the coating thickness is 65 μm. The performance of the high solid content, low surface treatment, moisture-curing epoxy resin coating is tested, and the results are shown in Table 1. Among them, the drying time refers to GB / T 1728-2020, the adhesion refers to GB / T 5210-2006, the impact strength refers to GB / T1732-2020, the solid content refers to GB / T 1725-2007, the acid, alkali and salt water resistance refers to GB / T9274-1988, and the salt spray resistance refers to GB / T 1771-2007.

[0075] Table 1 Performance test results of epoxy resin coatings of embodiments and comparative examples

[0076]

[0077] As can be seen from Table 1, the present invention reasonably selects the types of raw materials of component A and component B and reasonably controls the amount of each component to obtain a low-surface-treated moisture-curing epoxy resin coating with fast drying speed, good adhesion, high solid content and excellent corrosion resistance. The epoxy resin coating of the present invention has good drying ability regardless of whether it is under high temperature and high humidity or low temperature and high humidity environment, and the drying speed is very fast. Moreover, it has good adhesion, chemical resistance and salt spray resistance on a substrate with a solid rust layer.

[0078] The above is only a preferred embodiment of the present invention. It should be pointed out that for ordinary technicians in this technical field, several improvements and modifications can be made without departing from the principle of the present invention. These improvements and modifications should also be regarded as the scope of protection of the present invention.

Claims

1. A high solid content, low surface treatment, moisture-curing epoxy resin coating, characterized in that: It comprises component A and component B, and the mass ratio of component A to component B is 6 to 8:1; The component A comprises the following components in parts by weight: 30-40 parts of epoxy resin, 5-10 parts of polyurethane resin, 10-15 parts of red iron oxide, 10-15 parts of anti-rust filler, 1-3 parts of rust conversion agent, 1-3 parts of anti-settling agent, 0.3-0.5 parts of defoamer, 2-5 parts of functional filler, 0.5-0.8 parts of dispersant, 8-12 parts of active diluent, and 10-15 parts of organic solvent; The B component comprises the following components in parts by weight: 40 to 50 parts of a modified amine curing agent, 20 to 25 parts of a Mannich base curing agent, and 20 to 25 parts of an organic solvent.

2. The high solid content, low surface treatment, moisture-curing epoxy resin coating according to claim 1, characterized in that: The epoxy resin is one or more of 128 epoxy resin, E20 epoxy resin and 828 epoxy resin.

3. The high solid content, low surface treatment, moisture-curing epoxy resin coating according to claim 1 or 2, characterized in that: The anti-rust filler is zinc phosphate and / or aluminum tripolyphosphate; the rust conversion agent is diphenylguanidine chromate and / or modified epoxy rust-bearing resin.

4. The high solid content, low surface treatment, moisture-curing epoxy resin coating according to claim 3, characterized in that: The anti-settling agent is organic bentonite and / or fumed silica, the defoaming agent is a fluorosilicone-modified polysiloxane defoaming agent; and the functional filler comprises one or more of precipitated barium sulfate, quartz powder and talcum powder.

5. The high solid content, low surface treatment, moisture-curing epoxy resin coating according to claim 4, characterized in that: The active diluent is alkyl glycidyl ether, and the organic solvents in component A and component B are independently one or more of xylene, n-butanol and anhydrous ethanol.

6. The high solid content, low surface treatment, moisture curing epoxy resin coating according to claim 1, characterized in that: The modified amine curing agent is a cashew nut shell oil modified amine epoxy resin curing agent.

7. The method for preparing a high solid content, low surface treatment, moisture curing epoxy resin coating according to any one of claims 1 to 6, characterized in that: The following steps are included: 1) mixing epoxy resin, polyurethane resin, anti-settling agent, defoaming agent and dispersant to obtain a mixture; 2) mixing the mixed material, red iron oxide, anti-rust filler, rust conversion agent, functional filler, active diluent and organic solvent and refining the mixture to obtain component A; 3) Mixing the modified amine curing agent, the Mannich base curing agent and the organic solvent to obtain component B.

8. The preparation method according to claim 7, characterized in that: The mixing speed of step 1) is 600-700 r / min, and the mixing time is 5-10 min; the mixing speed of step 2) is 700-900 r / min, and the mixing time is 10-15 min; the mixing speed of step 3) is 500-600 r / min, and the mixing time is 10-15 min.

9. Use of the high solid content, low surface treatment, moisture curing epoxy resin coating according to any one of claims 1 to 6 in oil tanks.

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