Anticorrosive water-based paint

Abstract

The invention relates to an anticorrosive water-based paint, and belongs to the technical field of paints. The water-based paint comprises a component A and a component B, the component A comprises water-based resin, modified fibers, an auxiliary agent and deionized water; the component B comprises a curing agent and deionized water; wherein the modified fibers are positioned on the surface layer of the coating after the coating is cured. According to the water-based paint, the volatilization rate of a solvent on the surface of a coating is effectively reduced, coating shrinkage, breakage and internal defects caused by rapid volatilization of the solvent are reduced, the resistance of the coating to corrosive media is improved, and therefore the corrosion resistance of the coating is improved.

Description

Technical Field

[0001] The invention belongs to the technical field of coatings and relates to an anti-corrosion water-based coating. Background Art

[0002] To meet the storage and use requirements of water-based anti-corrosion coatings, large amounts of solvent are typically added. During the coating formation process, solvent evaporation, which causes shrinkage, cracking, and internal defects, is unavoidable. These problems can severely weaken the coating's resistance to corrosive media and significantly reduce its service life. Summary of the Invention

[0003] The purpose of the present invention is to provide an anti-corrosion water-based coating to enhance the resistance of the coating to corrosive media and improve its anti-corrosion performance.

[0004] The purpose of the present invention can be achieved through the following technical solutions: An anti-corrosion water-based paint comprising a component A and a component B; The component A includes water-based resin, modified fiber, additives, and deionized water; The B component includes a curing agent and deionized water; Wherein, the modified fiber is located in the surface layer of the coating when the coating is solidified.

[0005] Preferably, the modified fiber is a modified ceramic fiber, and a functional group covalently bonded to the curing agent is grafted onto the surface of the modified fiber; and the modified fiber is compounded with propylene glycol methyl ether acetate.

[0006] Preferably, the functional group is an epoxy group, and the curing agent is a phenolic amine epoxy curing agent.

[0007] Preferably, the length of the modified ceramic fiber is 1-2 mm.

[0008] Preferably, the preparation of the modified fiber is specifically as follows: A1. Ceramic fiber pretreatment; A2, epoxy groups grafted onto the surface of ceramic fiber; A3. Ceramic fiber composited with propylene glycol methyl ether acetate: prepare a mixed solution of propylene glycol methyl ether acetate and anhydrous ethanol, place ceramic fiber with epoxy groups grafted on the surface into the mixed solution, immerse, ultrasonicate, filter, wash, and dry to obtain modified fiber.

[0009] Preferably, in step A3, before the ceramic fiber with epoxy groups grafted on its surface is placed in the mixed solution of propylene glycol methyl ether acetate and anhydrous ethanol, the ceramic fiber with epoxy groups grafted on its surface is first placed in an oxygen plasma treatment device for treatment.

[0010] Preferably, the component A comprises the following raw materials in parts by weight: 50-70 parts of water-based resin, 0.5-1 parts of modified fiber, 3-8 parts of additives, and 20-30 parts of deionized water; the component B comprises the following raw materials in parts by weight: 10-30% of curing agent and the balance of deionized water.

[0011] Preferably, the mass ratio of component A to component B is (7-9):1.

[0012] Preferably, the water-based resin is one or more of a water-based epoxy resin, a water-based polyurethane resin or a water-based acrylic resin.

[0013] Preferably, the auxiliary agent comprises the following components in parts by weight: 0.5-2 parts of a dispersant, 0.1-0.5 parts of a defoaming agent, 0.1-0.3 parts of a pH regulator, 0.05-0.2 parts of a preservative and 0.5-2 parts of a film-forming auxiliary agent.

[0014] Beneficial effects of the present invention: The anti-corrosion water-based coating of the present invention has significant advantages. When the coating is cured, the modified ceramic fiber presents a unique pore structure and can be more located in the surface layer of the coating when the coating is cured, effectively blocking the volatilization path of the solvent in the coating and slowing down the volatilization of the solvent; at the same time, the propylene glycol methyl ether acetate compounded on the modified fiber has hydrophilic properties and can be tightly combined with the coating surface, further slowing down the solvent volatilization rate, effectively reducing the shrinkage stress of the coating, reducing the generation of defects such as internal microcracks and voids, enhancing the coating's resistance to fracture, making the coating structure more compact and complete, and the compact coating structure can effectively hinder the penetration of moisture, oxygen and corrosive ions, thereby improving the coating's resistance to corrosive media and overall anti-corrosion performance. DETAILED DESCRIPTION

[0015] In order to further illustrate the technical means and effects adopted by the present invention to achieve the predetermined purpose of the invention, the specific implementation methods, structures, features and effects of the present invention are described in detail below in combination with preferred embodiments.

[0016] In the field of coatings technology, water-based anti-corrosion coatings often require the addition of large amounts of solvents to meet storage and usage requirements. However, during the coating formation phase, rapid evaporation of the solvents causes the coating to shrink, break, and develop internal defects, severely weakening its ability to resist corrosive media and shortening its service life. When those skilled in the art work to solve this problem, they often focus on optimizing the coating formula and improving the construction process. For example, they adjust the types and ratios of water-based resins and additives in an attempt to enhance the coating's stability and film-forming properties; they also improve temperature, humidity, and other conditions during the construction process in the hope of reducing the negative impact of solvent evaporation. However, while simple formula optimization can improve the basic performance of the coating to a certain extent, it cannot fundamentally prevent the damage caused by solvent evaporation to the coating structure. Adjustments to the construction process only provide limited control over the external environment and are unlikely to resolve the core issue of solvent evaporation. After in-depth research, the inventors discovered that the key to the coating's deteriorating performance lies in a series of adverse effects caused by solvent evaporation. Conventional methods only address the exterior of the coating, failing to directly address the pain point of rapid solvent evaporation. To overcome this impasse, the inventors screened and researched various materials, ultimately selecting a modified fiber with a unique structure. They innovatively incorporated it into a water-based coating system, ensuring that it resides on the surface during coating curing.

[0017] During the coating curing process, the synergistic effect of the modified fiber's porous structure and propylene glycol methyl ether acetate effectively reduces the solvent volatilization rate, reduces internal coating defects, and significantly enhances the coating's resistance to fracture and corrosive media. Compared to traditional optimization methods, this technical solution directly addresses the pain points, fundamentally improving the anti-corrosion performance of water-based coatings and providing an innovative solution for the development of the coatings industry. The modified fibers used in the following examples of the present invention were prepared according to the following steps: A1. Ceramic fiber pretreatment: The ceramic fibers were placed in 5% sulfuric acid and ultrasonically dispersed for 30 minutes, followed by reflux treatment in an 80°C water bath for 2 hours to remove surface impurities and activate surface functional groups. The acid-washed ceramic fibers were then washed with deionized water until neutral, and then immersed in a 5% sodium hydroxide solution and stirred at 60°C for 1.5 hours to further activate the surface hydroxyl groups. Finally, the pretreated ceramic fibers were repeatedly washed with deionized water until neutral, and dried in a vacuum drying oven at 60°C for 12 hours to obtain pretreated ceramic fibers. A2. Epoxy groups grafted onto the surface of ceramic fibers: In a three-necked flask, 100 g of pretreated ceramic fiber and 500 mL of anhydrous ethanol were added, and epichlorohydrin in an amount of 10% of the mass of the ceramic fiber was slowly added dropwise while stirring, while nitrogen was introduced for protection; after the addition was completed, 50 ml of 0.5 mol / L sodium hydroxide aqueous solution was added to adjust the pH of the reaction system to 8-9; then refluxed in a 70 ° C oil bath for 5 hours with continuous stirring; after the reaction was completed, the mixture was alternately washed with ethanol and deionized water until neutral, and then dehydrated with acetone; finally, dried in a vacuum drying oven at 60 ° C for 12 hours to obtain ceramic fibers with surface grafted epoxy groups; A3, Ceramic fiber composite PMA: The ceramic fibers grafted with epoxy groups on the surface were placed in an oxygen plasma treatment device and treated for 10 minutes at a vacuum of 0.1 Pa and a power of 50 W to activate the hydroxyl and epoxy groups on the fiber surface. Subsequently, 500 ml of a mixed solution of propylene glycol methyl ether acetate and anhydrous ethanol in a volume ratio of 1:1 was prepared, and 1.5 g of p-toluenesulfonic acid was added as a catalytic co-agent. The activated surface-grafted epoxy-group ceramic fiber was placed in the mixed solution and vacuum impregnated at a vacuum degree of -0.08 MPa for 1 hour to expel air from the fiber pores and promote PMA penetration. Next, the system was transferred to a 40°C constant-temperature water bath and immersed for 8 hours with continuous stirring. During the immersion process, ultrasonic treatment (frequency 40kHz, power 200W) was performed for 30 minutes to ensure that the PMA fully filled the fiber pores and weakly esterified with the surface functional groups. After the immersion was completed, the fibers were collected by vacuum filtration and washed three times with anhydrous ethanol to remove unbound PMA and catalyst residues. Finally, the fibers were dried in a vacuum drying oven at 40°C for 12 hours to obtain modified fibers. The ceramic fibers were alumina fibers with a length of 1-2 mm.

[0018] The water-based resin used in the following embodiments of the present invention is a water-based epoxy resin.

[0019] The dispersant used in the following examples of the present invention is a polycarboxylate dispersant, specifically ZH-6007.

[0020] The defoaming agent used in the following examples of the present invention is a polysiloxane defoaming agent, specifically BYK-022.

[0021] The pH regulator used in the following examples of the present invention is diethanolamine.

[0022] The preservative used in the following examples of the present invention is an isothiazolinone, specifically Kathon CG.

[0023] The film-forming aid used in the following examples of the present invention is propylene glycol butyl ether.

[0024] The curing agent used in the following examples of the present invention is a phenalkamine epoxy curing agent, specifically T31 curing agent.

[0025] All raw materials of the present invention are not particularly limited in their sources and can be purchased from the market or prepared according to conventional methods well known to those skilled in the art.

[0026] There is no particular limitation on the purity of all raw materials in the present invention. The present invention preferably uses industrial pure materials or materials with conventional purity requirements in the field of thermal insulation coating preparation.

[0027] All raw materials in the present invention, their brands and abbreviations are conventional brands and abbreviations in the field. Each brand and abbreviation is clear and unambiguous in the field of its relevant use. Those skilled in the art can purchase them from commercial sources or prepare them by conventional methods based on the brand, abbreviation and corresponding use.

[0028] Example 1 Preparation of an anti-corrosion water-based coating: 60 parts of waterborne epoxy resin, 0.75 parts of modified fiber, 3 parts of additives, and 20 parts of deionized water were stirred at 800 rpm for 20 minutes to obtain component A; The auxiliary agent is prepared by mixing the following components in parts by weight: 0.5 parts of ZH-6007, 0.1 parts of BYK-022, 0.3 parts of diethanolamine, 0.2 parts of Kathon CG and 2 parts of propylene glycol butyl ether; and the length of the modified fiber is 1 mm.

[0029] 10 parts of T31 curing agent and 90 parts of deionized water were magnetically stirred for 10 minutes to obtain component B.

[0030] Component A and component B were mixed in a mass ratio of 7:1, and stirred at 500 rpm for 15 minutes to obtain a water-based coating.

[0031] Example 2 Preparation of an anti-corrosion water-based coating: 50 parts of waterborne epoxy resin, 1 part of modified fiber, 5 parts of additives, and 25 parts of deionized water were stirred at 800 rpm for 20 minutes to obtain component A; The auxiliary agent is prepared by mixing the following components in parts by weight: 1 part of ZH-6007, 0.5 part of BYK-022, 0.1 part of diethanolamine, 0.1 part of Kathon CG and 1 part of propylene glycol butyl ether; and the length of the modified fiber is 2 mm.

[0032] Component B was obtained by magnetically stirring 20 parts of T31 curing agent and 80 parts of deionized water for 10 minutes.

[0033] Component A and component B were mixed in a mass ratio of 8:1, and stirred at 500 rpm for 15 minutes to obtain a water-based coating.

[0034] Example 3 Preparation of an anti-corrosion water-based coating: 70 parts of waterborne epoxy resin, 0.5 parts of modified fiber, 8 parts of additives, and 30 parts of deionized water were stirred at 800 rpm for 20 minutes to obtain component A; The auxiliary agent is prepared by mixing the following components in parts by weight: 2 parts of ZH-6007, 0.3 parts of BYK-022, 0.2 parts of diethanolamine, 0.05 parts of Kathon CG and 0.5 parts of propylene glycol butyl ether; and the length of the modified fiber is 1 mm.

[0035] 30 parts of T31 curing agent and 70 parts of deionized water were magnetically stirred for 10 minutes to obtain component B.

[0036] Component A and component B were mixed in a mass ratio of 9:1, and stirred at 500 rpm for 15 minutes to obtain a water-based coating.

[0037] Comparative Example 1 The difference from Example 1 is that no modified fiber is added to component A.

[0038] Comparative Example 2 The difference from Example 1 is that an equal amount of alumina fiber is used in component A instead of the modified fiber.

[0039] Comparative Example 3 The difference from Example 1 is that no epoxy groups are grafted onto the surface of the modified fiber.

[0040] Comparative Example 4 The difference from Example 1 is that the modified fiber is not compounded with propylene glycol methyl ether acetate.

[0041] Comparative Example 5 The difference from Example 1 is that the modified fiber is not treated with oxygen plasma.

[0042] Comparative Example 6 The difference from Example 1 is that the length of the modified fiber is 0.5 mm.

[0043] Comparative Example 7 The difference from Example 1 is that the length of the modified fiber is 3 mm.

[0044] Test Case The performance of the water-based coatings prepared in Examples 1-3 and Comparative Examples 1-6 was tested respectively.

[0045] The performance testing methods and standards used in this test case are as follows: (1) Solvent evaporation rate test Test sample: The water-based coatings prepared in Examples 1-3 and Comparative Examples 1-7 were evenly scraped onto a glass plate (size 100 mm × 100 mm × 2 mm, surface degreased with ethanol) with a wet film thickness of 100 μm, ensuring that the coating was flat and free of bubbles.

[0046] Test: According to the provisions of the national standard GB / T1728-2020, the surface drying time and actual drying time of the paint film are measured. The surface drying time of the paint film is tested according to Method B, and the actual drying time of the paint film is tested according to Method A.

[0047] Test method for paint film surface drying time: touch the paint film surface with your finger. If it feels a little sticky but no paint sticks to your finger, the paint film surface is considered dry.

[0048] Test method for paint film drying time: Place a piece of qualitative filter paper on the paint film with the smooth surface of the filter paper in contact with the paint film. Gently place a drying tester on the filter paper and start the stopwatch at the same time. After 30 seconds, remove the dryer and turn the sample over with the paint film facing down, or tap the test plate lightly on the back with the index finger of the hand holding the plate. If the filter paper can fall freely and there is no filter paper fiber on the paint film, the paint film is considered to be dry.

[0049] (2) Salt spray test: The water-based coatings prepared in Examples 1-3 and Comparative Examples 1-7 were sprayed onto cold-rolled steel sheets measuring 150 mm × 75 mm × 1.5 mm. After drying for 7 days, the sheets were edge-sealed. The test was conducted in accordance with the test method specified in GB / T 1771-2007, "Paints and varnishes - Determination of resistance to neutral salt spray." The coatings were placed in a salt spray chamber (Q-LABCCT600) containing 5% sodium chloride solution for 48 hours, and the corrosion damage of the coatings was observed. The corrosion grade of the coatings in the salt spray test was evaluated in accordance with the coating damage evaluation criteria specified in GB / T 1766-2008, "Paints and varnishes - Rating of coating ageing." The coating thickness was 50 ± 10 μm.

[0050] (3) Electrochemical impedance spectroscopy (EIS) Test sample: A 150×70×1 mm Q235 carbon steel sheet was sandblasted to Sa2.5 level with a roughness of Ra = 50±10 μm, and then coated with the water-based coatings of Examples 1-3 and Comparative Examples 1-7 using a gap-type wet film preparation apparatus, with a dry film thickness of 100±5 μm, and cured at room temperature.

[0051] Test method: The sample coated with water-based paint is used as the working electrode (test area 1cm 2The rest of the parts were encapsulated with oil-soluble heavy-duty anti-corrosion epoxy resin). A saturated calomel electrode was used as the reference electrode, and a platinum electrode was used as the counter electrode to form a three-electrode system. The CH1660E electrochemical workstation (frequency range , amplitude 10mV), the impedance modulus of the test coating after immersion in 3.5% NaCl solution for 7 days, the equivalent circuit was fitted using ZView software, and the low-frequency (0.01Hz) impedance modulus |Z| was taken as the coating protection performance index.

[0052] The test data of the above three tests are shown in Table 1.

[0053] As shown in Table 1, the present invention improves the corrosion resistance of water-based coatings by adding specific modified fibers to component A of the coating, positioning them at the surface during coating curing. The epoxy groups grafted onto the modified fiber surface, the propylene glycol methyl ether acetate complex, and the appropriate fiber length slow the evaporation rate of the coating solvent, reducing coating shrinkage, fracture, and internal defects, thereby enhancing the coating's resistance to corrosive media.

[0054] The above description is merely a preferred embodiment of the present invention and does not constitute any form of limitation to the present invention. Although the present invention has been disclosed as a preferred embodiment as above, it is not intended to limit the present invention. Any person skilled in the art can make some changes or modifications to equivalent embodiments using the technical contents disclosed above without departing from the scope of the technical solution of the present invention. However, any brief modifications, equivalent changes and modifications made to the above embodiments based on the technical essence of the present invention without departing from the content of the technical solution of the present invention still fall within the scope of the technical solution of the present invention.

Claims

1. An anti-corrosion water-based paint, characterized in that: It includes component A and component B; The component A includes water-based resin, modified fiber, additives, and deionized water; The B component includes a curing agent and deionized water; Wherein, the modified fiber is located in the surface layer of the coating when the coating is solidified.

2. The anti-corrosion water-based paint according to claim 1, characterized in that: The modified fiber is a modified ceramic fiber, and a functional group covalently bonded with the curing agent is grafted on the surface of the modified fiber; the modified fiber is compounded with propylene glycol methyl ether acetate.

3. The anti-corrosion water-based paint according to claim 2, characterized in that: The functional group is an epoxy group, and the curing agent is a phenolic amine epoxy curing agent.

4. The anti-corrosion water-based paint according to claim 2, characterized in that: The length of the modified ceramic fiber is 1-2 mm.

5. The anti-corrosion water-based paint according to claim 3, characterized in that: The preparation of the modified fiber is specifically as follows: A1. Ceramic fiber pretreatment; A2, epoxy groups grafted onto the surface of ceramic fiber; A3. Ceramic fiber composited with propylene glycol methyl ether acetate: prepare a mixed solution of propylene glycol methyl ether acetate and anhydrous ethanol, place ceramic fiber with epoxy groups grafted on the surface into the mixed solution, immerse, ultrasonicate, filter, wash, and dry to obtain modified fiber.

6. The anti-corrosion water-based paint according to claim 5, characterized in that: In step A3, Before the ceramic fiber with epoxy groups grafted on its surface is placed in a mixed solution of propylene glycol methyl ether acetate and anhydrous ethanol, the ceramic fiber with epoxy groups grafted on its surface is first placed in an oxygen plasma treatment device for treatment.

7. The anti-corrosion water-based paint according to claim 1, characterized in that: The component A comprises the following raw materials in parts by weight: 50-70 parts of water-based resin, 0.5-1 parts of modified fiber, 3-8 parts of additives, and 20-30 parts of deionized water; the component B comprises the following raw materials in parts by weight: 10-30% of curing agent and the balance of deionized water.

8. The anti-corrosion water-based paint according to claim 7, characterized in that: The mass ratio of component A to component B is (7-9):

1.

9. The anti-corrosion water-based paint according to claim 1, characterized in that: The water-based resin is one or more of water-based epoxy resin, water-based polyurethane resin or water-based acrylic resin.

10. The anti-corrosion water-based paint according to claim 1, characterized in that: The auxiliary agent comprises the following components in parts by weight: 0.5-2 parts of a dispersant, 0.1-0.5 parts of a defoaming agent, 0.1-0.3 parts of a pH regulator, 0.05-0.2 parts of a preservative and 0.5-2 parts of a film-forming auxiliary agent.

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