Low-temperature curing anticorrosive paint and preparation method thereof

Abstract

The invention relates to the technical field of coatings, in particular to a low-temperature curing anticorrosive coating and a preparation method thereof. The coating is composed of a component A and a component B, and the mass ratio of the component A to the component B is 100: (3-50.8); the component A comprises the following components in parts by weight: 25-35 parts of epoxy resin, 40-72 parts of pigment filler, 2.3-4.5 parts of an auxiliary agent and 10-14 parts of a solvent; the component B is a modified phenolic aldehyde amine curing agent; the epoxy resin is used as a main film-forming substance and is matched with the modified phenolic aldehyde amine curing agent to prepare the low-temperature curing epoxy coating, so that the problem that the epoxy coating cannot be cured at the temperature lower than-10 DEG C is solved, and a coating formed by the coating provided by the invention has good mechanical properties, salt spray resistance, high and low temperature resistance and the like.

Description

Technical Field

[0001] The present invention relates to the technical field of coatings, and in particular to a low-temperature curing anti-corrosion coating and a preparation method thereof. Background Art

[0002] Epoxy coatings are widely used in heavy corrosion protection fields such as petrochemicals, marine vessels, and aerospace due to their good thermal stability, mechanical properties, and anti-corrosion properties.

[0003] During use, epoxy coatings usually need to react with amine curing agents to form a three-dimensional cross-linked network structure before they can have excellent mechanical properties and anti-corrosion properties. However, the reaction between the epoxy group and the amino group of the amine curing agent is greatly affected by temperature. Conventional polyamide, fatty amine, alicyclic amine and other amine curing agents require an ambient temperature above 0°C to react, and the reaction rate decreases as the temperature decreases. Even if the more reactive cardanol-modified phenolic amine curing agent is used, the reaction temperature of the coating needs to be above -5°C. However, in some places with low temperatures in winter, the lowest temperature can reach -50°C, and the low temperature lasts for a long time, and the long-term low temperature can reach -10°C~-20°C, which will greatly extend the protective coating cycle. Therefore, it is of great significance to develop an epoxy anti-corrosion coating that can achieve low-temperature curing. Summary of the Invention

[0004] In view of the shortcomings of the existing technology, the purpose of the present invention is to propose a low-temperature curing anti-corrosion coating and a preparation method thereof, which solves the problem that epoxy coating cannot be cured below minus ten degrees Celsius. The coating formed by the coating proposed by the present invention has good mechanical properties, salt spray resistance, high and low temperature resistance, etc.

[0005] To achieve the above object, the present invention adopts the following technical solutions: The present invention provides a low-temperature curing anti-corrosion coating, which is composed of component A and component B, wherein the mass ratio of component A to component B is 100:(3~50.8); The component A comprises the following components in parts by weight: 25-35 parts of epoxy resin, 40-72 parts of pigments and fillers, 2.3-4.5 parts of additives, and 10-14 parts of solvents; The B component is a modified phenalkamine curing agent.

[0006] Preferably, the epoxy resin is one of bisphenol A epoxy resin, bisphenol F epoxy resin, epoxy-modified phenolic resin, and epoxy-modified silicone resin.

[0007] More preferably, the epoxy resin is an epoxy-modified phenolic resin.

[0008] Preferably, the bisphenol A epoxy resin is 601 epoxy resin or 828 epoxy resin; the model of the bisphenol F epoxy resin is SMF-170; the model of the epoxy-modified phenolic resin is F-44; and the model of the epoxy-modified silicone resin is SMH-30.

[0009] Preferably, the modified phenalkamine curing agent is BS864M phenalkamine epoxy curing agent produced by Jiangxi Baisheng Chemical Company.

[0010] Preferably, the pigments and fillers include mica powder, silica powder, red iron oxide and barium sulfate, and the mass ratio of the mica powder, silica powder, red iron oxide and barium sulfate is (15~25): (15~25): (5~10): (5~10.7).

[0011] Preferably, the particle size of the mica powder is 400-700 mesh; the particle size of the silicon micropowder is 400-700 mesh; the particle size of the red iron oxide is 325-600 mesh; and the particle size of the barium sulfate is 400-700 mesh.

[0012] Preferably, the auxiliary agent includes: organic bentonite, silane coupling agent, dispersant, defoaming agent, and leveling agent, and the mass ratio of the organic bentonite, silane coupling agent, dispersant, defoaming agent, and leveling agent is (1-1.5): (1-1.5): (0.1-0.5): (0.1-0.5): (0.1-0.5).

[0013] Preferably, the organic bentonite is HFGEL-140SF organic bentonite produced by Zhejiang Fenghong; the silane coupling agent is 6040 adhesion promoter produced by Digao Company; the dispersant is BYK-104S dispersant produced by BYK Company of Germany; the defoamer is BYK-085 defoamer produced by BYK Company of Germany; and the leveling agent is BYK-390 leveling agent produced by BYK Company of Germany.

[0014] Preferably, the solvent is n-butanol, xylene or any combination thereof.

[0015] The present invention also provides a method for preparing a low-temperature curing anti-corrosion coating, comprising: The epoxy resin, the additive, and the solvent are mixed and dispersed at a speed of 1000-1500 r / min for 10-15 minutes to obtain a dispersion system, pigments and fillers are added to the dispersion system, and the mixture is dispersed at a speed of 1500-2500 r / min for 10-20 minutes to obtain component A; The component A and the modified phenolic amine curing agent are mixed evenly to obtain a low-temperature curing anti-corrosion coating.

[0016] Compared with the prior art, the present invention has the following beneficial effects: (1) The present invention uses epoxy resin as the main film-forming substance and a modified phenolic amine curing agent to prepare a low-temperature curing epoxy coating. The epoxy resin can undergo a ring-opening reaction with the amino group because of the epoxy group contained in its molecular chain. During the curing process, the drying time is affected by the activity of the amino group. The modified phenolic amine curing agent used in the present invention has a special molecular structure. In the modified phenolic amine curing agent molecule, the amino group is directly connected to the benzene ring, and there are two phenolic hydroxyl groups on the aromatic ring, which are in the para position. During the coating production process, the modified phenolic amine curing agent is easily oxidized to form a high molecular compound with a quinone group. The quinone group has a stronger conjugation effect with the amino group, which significantly increases the electron cloud density around the amino group, making the amino group more active, so that the coating can still react when the ambient temperature is below -10°C.

[0017] (2) The mica powder in the present invention is a flaky structural material. When used as a filler, it can extend the medium penetration distance, thereby improving the coating's resistance to medium penetration. The use of red iron oxide, silica powder, and barium sulfate as pigments and fillers can improve the density of the coating and further improve the coating's resistance to medium penetration. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] Figure 1 This is a sample photo of the salt spray test of the present invention; Figure 2 This is a photo of the sample subjected to the alternating temperature resistance test of the present invention. DETAILED DESCRIPTION

[0019] The following will clearly and completely describe the technical solutions in the embodiments of the present invention in conjunction with the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of the present invention.

[0020] Example 1 This embodiment provides a low-temperature curing anti-corrosion coating, which is composed of the following parts by weight: 25 parts of 601 epoxy resin, 15 parts of mica powder, 25 parts of silica powder, 10 parts of red iron oxide, 7 parts of barium sulfate, 1 part of HFGEL-140SF organic bentonite, 1.5 parts of 6040 adhesion promoter, 0.5 parts of BYK-104S dispersant, 0.5 parts of BYK-085 defoamer, 0.5 parts of BYK-390 leveling agent, 14 parts of n-butanol, and 9.4 parts of BS864M phenolic amine epoxy curing agent.

[0021] The preparation method of the low-temperature curing anticorrosive coating in this embodiment is as follows: 601 epoxy resin, HFGEL-140SF organobentonite, 6040 adhesion promoter, BYK-104S dispersant, BYK-085 defoamer, BYK-390 leveling agent, and n-butanol were mixed and dispersed at a speed of 1000 r / min for 15 minutes to obtain a dispersion system. Mica powder, silica powder, red iron oxide, and barium sulfate were sequentially added to the dispersion system and dispersed at a speed of 1500 r / min for 20 minutes to obtain component A. The A component and the BS864M phenolic amine epoxy curing agent are mixed evenly to obtain a low-temperature curing anti-corrosion coating.

[0022] Example 2 This embodiment provides a low-temperature curing anti-corrosion coating, which is composed of the following parts by weight: 27.5 parts of 828 epoxy resin, 18 parts of mica powder, 20 parts of silica powder, 7 parts of red iron oxide, 10.7 parts of barium sulfate, 1.2 parts of HFGEL-140SF organic bentonite, 1.4 parts of 6040 adhesion promoter, 0.4 parts of BYK-104S dispersant, 0.4 parts of BYK-085 defoamer, 0.4 parts of BYK-390 leveling agent, 13 parts of xylene, and 10.3 parts of BS864M phenolic amine epoxy curing agent.

[0023] The preparation method of the low-temperature curing anticorrosive coating in this embodiment is as follows: 828 epoxy resin, HFGEL-140SF organobentonite, 6040 adhesion promoter, BYK-104S dispersant, BYK-085 defoamer, BYK-390 leveling agent, and xylene were mixed and dispersed at a speed of 1200 r / min for 13 minutes to obtain a dispersion system. Mica powder, silica powder, red iron oxide, and barium sulfate were sequentially added to the dispersion system and dispersed at a speed of 1800 r / min for 18 minutes to obtain component A. The A component and the BS864M phenolic amine epoxy curing agent are mixed evenly to obtain a low-temperature curing anti-corrosion coating.

[0024] Example 3 This embodiment provides a low-temperature curing anti-corrosion coating, which is composed of the following parts by weight: 30 parts of SMF-170 bisphenol F epoxy resin, 20 parts of mica powder, 17.5 parts of silica powder, 5 parts of red iron oxide, 12 parts of barium sulfate, 1.3 parts of HFGEL-140SF organic bentonite, 1.3 parts of 6040 adhesion promoter, 0.3 parts of BYK-104S dispersant, 0.3 parts of BYK-085 defoamer, 0.3 parts of BYK-390 leveling agent, 6 parts of n-butanol, 6 parts of xylene, and 11.3 parts of BS864M phenolic amine epoxy curing agent.

[0025] The preparation method of the low-temperature curing anticorrosive coating in this embodiment is as follows: SMF-170 bisphenol F epoxy resin, HFGEL-140SF organobentonite, 6040 adhesion promoter, BYK-104S dispersant, BYK-085 defoamer, BYK-390 leveling agent, n-butanol, and xylene were mixed and dispersed at a speed of 1300 r / min for 12 minutes to obtain a dispersion system. Mica powder, silica powder, red iron oxide, and barium sulfate were sequentially added to the dispersion system and dispersed at a speed of 2000 r / min for 17 minutes to obtain component A. The A component and the BS864M phenolic amine epoxy curing agent are mixed evenly to obtain a low-temperature curing anti-corrosion coating.

[0026] Example 4 This embodiment provides a low-temperature curing anti-corrosion coating, which is composed of the following parts by weight: 32.5 parts of F-44 epoxy modified phenolic resin, 23 parts of mica powder, 19 parts of silica powder, 6.3 parts of red iron oxide, 5 parts of barium sulfate, 1.4 parts of HFGEL-140SF organic bentonite, 1.2 parts of 6040 adhesion promoter, 0.2 parts of BYK-104S dispersant, 0.2 parts of BYK-085 defoamer, 0.2 parts of BYK-390 leveling agent, 3.5 parts of n-butanol, 7.5 parts of xylene, and 12.2 parts of BS864M phenolic amine epoxy curing agent.

[0027] The preparation method of the low-temperature curing anticorrosive coating in this embodiment is as follows: F-44 epoxy-modified phenolic resin, HFGEL-140SF organobentonite, 6040 adhesion promoter, BYK-104S dispersant, BYK-085 defoamer, BYK-390 leveling agent, n-butanol, and xylene were mixed and dispersed at a speed of 1500 r / min for 10 minutes to obtain a dispersion system. Mica powder, silica powder, red iron oxide, and barium sulfate were sequentially added to the dispersion system and dispersed at a speed of 2300 r / min for 16 minutes to obtain component A. The A component and the BS864M phenolic amine epoxy curing agent are mixed evenly to obtain a low-temperature curing anti-corrosion coating.

[0028] Example 5 This embodiment provides a low-temperature curing anti-corrosion coating, which is composed of the following parts by weight: 35 parts of SMH-30 epoxy modified silicone resin, 25 parts of mica powder, 15 parts of silica powder, 5 parts of red iron oxide, 7.2 parts of barium sulfate, 1.5 parts of HFGEL-140SF organic bentonite, 1 part of 6040 adhesion promoter, 0.1 part of BYK-104S dispersant, 0.1 part of BYK-085 defoamer, 0.1 part of BYK-390 leveling agent, 8 parts of n-butanol, 2 parts of xylene, and 13.1 parts of BS864M phenolic amine epoxy curing agent.

[0029] The preparation method of the low-temperature curing anticorrosive coating in this embodiment is as follows: 601 epoxy resin, HFGEL-140SF organobentonite, 6040 adhesion promoter, BYK-104S dispersant, BYK-085 defoamer, BYK-390 leveling agent, n-butanol, and xylene were mixed and dispersed at a speed of 1400 r / min for 11 minutes to obtain a dispersion system. Mica powder, silica powder, red iron oxide, and barium sulfate were sequentially added to the dispersion system and dispersed at a speed of 2500 r / min for 10 minutes to obtain component A. The A component and the BS864M phenolic amine epoxy curing agent are mixed evenly to obtain a low-temperature curing anti-corrosion coating.

[0030] In the above embodiments, the particle size of the mica powder is within the range of 400 mesh to 700 mesh; the particle size of the silicon micropowder is within the range of 400 mesh to 700 mesh; the particle size of the red iron oxide is within the range of 325 mesh to 600 mesh; and the particle size of the barium sulfate is within the range of 400 mesh to 700 mesh.

[0031] The manufacturers of BYK-104S dispersant, BYK-085 defoamer, and BYK-390 leveling agent are all BYK of Germany; the manufacturer of 6040 adhesion promoter is Digo Company; the manufacturer of HFGEL-140SF organic bentonite is Zhejiang Fenghong; the manufacturer of BS864M phenolic amine epoxy curing agent is Jiangxi Baisheng Chemical Company.

[0032] Comparative Example 1 The difference between this comparative example and Example 1 is that in this comparative example, BS864M phenolic amine epoxy is replaced with polyamide curing agent 650, and the rest is the same as Example 1.

[0033] Comparative Example 2 The difference between this comparative example and Example 1 is that in this comparative example, BS864M phenolic amine epoxy is replaced by modified fatty amine curing agent BS8432, and the rest is the same as Example 1.

[0034] Comparative Example 3 The difference between this comparative example and Example 1 is that in this comparative example, BS864M phenalkamine epoxy is replaced with phenalkamine curing agent T31, and the rest is the same as Example 1.

[0035] Comparative Example 4 The difference between this comparative example and Example 1 is that in this comparative example, BS864M phenolic amine epoxy is replaced with cardanol-modified phenolic amine curing agent 6017, and the rest is the same as Example 1.

[0036] In order to better illustrate the beneficial effects of the present invention, the inventors dried the samples prepared with the coatings obtained in Examples 1-5 and Comparative Examples 1-4 at different temperatures for the same time in accordance with GB / T 1728-2020 "Determination of Drying Time of Paint Film and Putty Film". During each test, except for the different temperatures, the other conditions were the same to judge whether the samples were surface dry and thoroughly dry after drying. The test results are shown in Table 1.

[0037] Table 1 Sample surface dry and actual dry test results As can be seen from Table 1, the coating formed by using bisphenol A epoxy resin, bisphenol F epoxy resin, epoxy-modified phenolic resin, and epoxy-modified silicone resin as film-forming materials in combination with phenolic amine epoxy curing agent can still react when the ambient temperature is lower than -10 ° C, and the minimum reaction temperature can reach -18 ° C. This is because the amino group in the phenolic amine epoxy curing agent molecule is directly connected to the benzene ring, and there are two phenolic hydroxyl groups on the aromatic ring, and they are in the para position. This structure has been oxidized to form quinones, and there is a stronger conjugation effect between the quinone group and the amino group, which significantly improves the electron cloud density around the amino group and is more active, so that the coating can still react when the ambient temperature is lower than -10 ° C. The epoxy-modified phenolic resin used in Example 4 can still react at an ambient temperature of -20 ° C. This is because the functional group density of the epoxy-modified phenolic resin is higher, and the resin contains phenolic hydroxyl groups and methylol groups. The phenolic hydroxyl groups are weakly acidic and can be used as Lewis acid to catalyze epoxy ring opening. Therefore, the epoxy-modified phenolic resin and the phenolic amine epoxy curing agent can react at a lower temperature.

[0038] From the results of Comparative Examples 1-4, it can be seen that the coatings prepared from conventional polyamide, modified fatty amine, phenalkamine, and cardanol-modified phenalkamine combined with phenalkamine epoxy curing agent react significantly slower than the coating of the present invention at low temperatures. This is because the activity of amino groups is greatly affected by temperature. When the ambient temperature is too low, conventional epoxy coatings do not have reaction activity.

[0039] The inventors also conducted performance tests on the coatings obtained in Examples 1-5 and Comparative Examples 1-4, as follows: Solid content test of coatings: The samples were tested in accordance with GB / T 1725-2007 “Paints, varnishes and plastics - Determination of non-volatile matter content”.

[0040] Volatile organic compound content test of coatings: The samples were measured in accordance with GB / T 23986-2009 "Paints and varnishes - Determination of volatile organic compound (VOC) content - Gas chromatography method".

[0041] Paint adhesion test: The samples were tested in accordance with GB / T 5210-2006 "Paints and varnishes - Adhesion test by pull-off method".

[0042] Salt spray resistance of coatings: The samples were tested in accordance with GB / T 1771-2007 “Paints and varnishes - Determination of resistance to neutral salt spray”.

[0043] The coating's resistance to alternating temperature: The samples were tested in accordance with JG / T 25-2017 "Test method for temperature change resistance of architectural coatings".

[0044] The performance test results of the coatings obtained in Examples 1-5 are shown in Table 2, and the test results of the coatings obtained in Comparative Examples 1-4 are shown in Table 3.

[0045] Table 2 Performance test results of the coatings obtained in Examples 1-5 Table 3 Performance test results of the coatings obtained in Comparative Examples 1-4 It can be seen from Table 2 and Table 3 that the coating proposed by the present invention has excellent comprehensive performance.

[0046] The specific embodiments of the present invention are provided to enable those skilled in the art to understand or implement the present invention. Various modifications to these embodiments will be apparent to those skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the present invention.

[0047] It should be understood that the present invention is not limited to the above description and that various modifications and changes may be made without departing from the scope thereof. The scope of the present invention is limited only by the appended claims.

Claims

1. A low-temperature curing anti-corrosion coating, characterized in that: Composed of component A and component B, wherein the mass ratio of component A to component B is 100:(3-50.8); The component A comprises the following components in parts by weight: 25-35 parts of epoxy resin, 40-72 parts of pigments and fillers, 2.3-4.5 parts of additives, and 10-14 parts of solvents; The B component is a modified phenalkamine curing agent.

2. The low-temperature curing anti-corrosion coating according to claim 1, characterized in that: The epoxy resin is one of bisphenol A epoxy resin, bisphenol F epoxy resin, epoxy-modified phenolic resin and epoxy-modified silicone resin.

3. The low-temperature curing anti-corrosion coating according to claim 2, characterized in that: The epoxy resin is epoxy-modified phenolic resin.

4. The low-temperature curing anti-corrosion coating according to claim 2, characterized in that: The bisphenol A epoxy resin is 601 epoxy resin or 828 epoxy resin; the model of the bisphenol F epoxy resin is SMF-170; the model of the epoxy-modified phenolic resin is F-44; and the model of the epoxy-modified silicone resin is SMH-30.

5. The low-temperature curing anti-corrosion coating according to claim 1, characterized in that: The model of the modified phenalkamine curing agent is BS864M.

6. The low-temperature curing anti-corrosion coating according to claim 1, characterized in that: The pigments and fillers include mica powder, silica powder, red iron oxide and barium sulfate.

7. The low-temperature curing anti-corrosion coating according to claim 6, characterized in that: The particle size of the mica powder is 400-700 mesh; the particle size of the silicon micropowder is 400-700 mesh; the particle size of the red iron oxide is 325-600 mesh; and the particle size of the barium sulfate is 400-700 mesh.

8. The low-temperature curing anti-corrosion coating according to claim 1, characterized in that: The auxiliary agents include organic bentonite, silane coupling agent, dispersant, defoamer and leveling agent; the solvent is one of n-butanol and xylene or a mixture of n-butanol and xylene in any mass ratio.

9. The low-temperature curing anti-corrosion coating according to claim 8, characterized in that: The model of the organic bentonite is HFGEL-140SF; the model of the silane coupling agent is 6040 adhesion promoter; the model of the dispersant is BYK-104S; the model of the defoamer is BYK-085; and the model of the leveling agent is BYK-390.

10. A method for preparing a low-temperature curing anti-corrosion coating, characterized in that: include: The epoxy resin, the additive, and the solvent are mixed and dispersed at a speed of 1000-1500 r / min for 10-15 minutes to obtain a dispersion system, pigments and fillers are added to the dispersion system, and the mixture is dispersed at a speed of 1500-2500 r / min for 10-20 minutes to obtain component A; The component A and the modified phenolic amine curing agent are mixed evenly to obtain a low-temperature curing anti-corrosion coating.

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