A coating and its preparation method and application, and coated product

Abstract

The present invention belongs to the technical field of polymer materials, and specifically discloses a coating, a preparation method and application thereof, and a coated product. The raw material components of the coating of the present invention include, by weight: 50 to 200 parts of a hyperbranched bisphenol A epoxy resin composition and 1 to 100 parts of a curing agent composition; wherein the hyperbranched bisphenol A epoxy resin contains a bisphenol A group, a glycidylamine group, a glycidyl ether group, and an aliphatic ring group. The present invention uses a hyperbranched bisphenol A epoxy resin and selects and optimizes its components to achieve the effects of lowering the processing temperature of the epoxy resin coating, enhancing heat resistance, enhancing permeability, or enhancing rust resistance; the anti-corrosion coating and coated product prepared by the coating have the characteristics of high coating density, strong permeability, and high heat resistance, and can meet the application requirements in harsh environments such as high humidity and heat, acid and alkali corrosion, etc.

Description

Technical Field

[0001] The present invention relates to the technical field of polymer materials, and in particular to a coating, a preparation method and application thereof, and a coated product. Background Art

[0002] Epoxy resin is an important thermosetting resin with good comprehensive properties, including excellent mechanical properties, electrical insulation properties, chemical resistance and adhesion, which also makes it widely used in coatings, adhesives, electronic device packaging, aerospace, microelectronic materials and other fields. The coating with epoxy resin as the main film-forming substance is called epoxy resin coating. Epoxy resin coating is one of the most widely used protective coatings. The coating formed by it not only has a shielding effect on corrosive media, but also can passivate the protected metal and play an electrochemical role.

[0003] In the related art, taking bisphenol A epoxy resin as an example, the epoxy resin molten powder based only on bisphenol A epoxy resin has the problems of poor wet heat stability, poor dielectric properties, and low high-temperature residual mass fraction due to the presence of water-absorbing hydroxyl groups in its cross-linked network structure and low cross-linking density. The coating prepared based on the above epoxy resin molten powder is also greatly limited in its application in extremely harsh environments such as high humidity and heat, acid and alkali corrosion, etc.

[0004] Therefore, it is an urgent problem to provide a coating material that can be used in extremely harsh environments such as high humidity, heat, acid and alkali corrosion, and has good corrosion resistance, high temperature resistance, and strong adhesion. Summary of the invention

[0005] The present invention aims to solve at least one of the technical problems existing in the prior art. To this end, the present invention proposes a coating and its preparation method and application, and coated products, aiming to solve the problem that the coating currently prepared from ordinary epoxy resin is difficult to meet the application requirements in extremely harsh environments such as high humidity and heat, acid and alkali corrosion. The present invention optimizes the type of epoxy resin in the epoxy resin coating to achieve the modification of the corrosion resistance of the coating, and then combines the effect of the curing agent composition to further improve the corrosion resistance, bonding performance and high temperature resistance of the coating, so that the coating and coated products of the present invention can meet the application requirements in extremely harsh environments such as high humidity and heat, acid and alkali corrosion.

[0006] The embodiment of the first aspect of the present invention provides a coating, wherein the raw material components of the coating include, by weight: 50 to 200 parts of a hyperbranched bisphenol A epoxy resin composition, and 1 to 100 parts of a curing agent composition;

[0007] The hyperbranched bisphenol A epoxy resin contains bisphenol A groups, glycidyl amine groups, glycidyl ether groups and aliphatic ring groups.

[0008] The coating according to the embodiment of the first aspect of the present invention has at least the following beneficial effects: the coating provided by the present invention realizes the modification of the corrosion resistance of the epoxy resin coating by using a hyperbranched bisphenol A epoxy resin; the bisphenol A group contained in the hyperbranched bisphenol A epoxy resin can provide the adhesion between the coating and the substrate material, so that the coating and the substrate are not easily separated during the bonding process; the glycidylamine group in the hyperbranched bisphenol A epoxy resin helps to improve the heat resistance of the epoxy resin after curing; the combination of glycidyl ether group and glycidylamine group can effectively improve the heat resistance of the epoxy resin after curing while maintaining the easy processability of the resin; the aliphatic ring group helps to improve the mechanical properties of the epoxy resin after curing; in addition, the large conjugation effect formed between the high benzene ring group content of the hyperbranched bisphenol A epoxy resin helps to slow down the penetration of corrosive media; and its hyperbranched structure can provide multiple cross-linkable sites, which can form a high-density cross-linked network in the cross-linked network of the coating, thereby improving the heat resistance of the coating. Therefore, the present invention can achieve the effects of lowering the processing temperature of epoxy resin coating, enhancing heat resistance, enhancing anti-permeability or enhancing anti-rust performance by modifying the coating with a hyperbranched bisphenol A epoxy resin containing multiple groups, thereby meeting the application requirements in extremely harsh environments such as high humidity and heat, acid and alkali corrosion, etc.

[0009] In some embodiments of the present invention, the raw material components of the coating include, by weight: 80 to 160 parts of a hyperbranched bisphenol A epoxy resin composition and 10 to 40 parts of a curing agent composition.

[0010] The present invention optimizes the formula and dosage of two main components in the coating, further improves the curing effect of the curing agent composition on the hyperbranched bisphenol A epoxy resin composition, and achieves better improvement effects on reducing the processing temperature of the epoxy resin coating, enhancing heat resistance, enhancing anti-permeability or enhancing anti-rust performance.

[0011] In some embodiments of the present invention, the hyperbranched bisphenol A epoxy resin includes a first epoxy resin, a second epoxy resin and a third epoxy resin;

[0012] The first epoxy resin contains bisphenol A groups and glycidylamine groups;

[0013] The second epoxy resin contains bisphenol A groups, glycidyl ether groups and glycidyl amine groups;

[0014] The third epoxy resin contains a bisphenol A group and an aliphatic ring group.

[0015] Each epoxy resin in the hyperbranched bisphenol A epoxy resin composition of the present invention contains functional groups respectively. These epoxy resins interact with each other, and each functional group plays a synergistic role, so that the finally formed epoxy resin coating has better resistance to moisture and heat and acid and alkali corrosion.

[0016] In some embodiments of the present invention, the epoxide value of the hyperbranched bisphenol A epoxy resin is 0.6 to 1.2.

[0017] The invention helps to promote the function of each functional group in the epoxy resin composition by selecting a hyperbranched bisphenol A epoxy resin with a higher epoxy value. Combined with the hyperbranched structure in the hyperbranched bisphenol A epoxy resin, a better high-density cross-linked network can be formed in the coating, thereby improving the heat resistance and corrosion resistance of the coating prepared by the coating.

[0018] In some embodiments of the present invention, the epoxy value of the first epoxy resin is 0.7-1.05; and / or, the epoxy value of the second epoxy resin is 0.6-0.95; and / or, the epoxy value of the third epoxy resin is 0.9-1.2.

[0019] In some embodiments of the present invention, the hyperbranched bisphenol A epoxy resin includes AFG-90 epoxy resin, AG-80 epoxy resin and AG-602 epoxy resin.

[0020] The invention optimizes the components of a hyperbranched bisphenol A epoxy resin composition, and selects AFG-90 epoxy resin, AG-80 epoxy resin and AG-602 epoxy resin for combination, wherein the AFG-90 epoxy resin has an epoxy value of 0.85-0.9, contains a bisphenol A group and a glycidylamine group in its structure, and because of its high epoxy value and nitrogen atom, it is helpful to improve the heat resistance of the epoxy resin after curing; the AG-80 epoxy resin has an epoxy value of 0.75-0.8, contains a bisphenol A group, a glycidyl ether and a glycidylamine group in its structure, has a high epoxy value and contains a phenyl ether bond, can effectively improve the heat resistance of the epoxy resin after curing while maintaining the easy processability of the resin; the AG-602 epoxy resin has an epoxy value of 1.06, contains a bisphenol A group and an alicyclic group in its structure, has a high epoxy value and a high degree of branching, and can effectively improve the mechanical properties of the epoxy resin after curing. The combined use of three hyperbranched bisphenol A epoxy resins can enhance the water resistance of the resin, reduce internal stress, improve adhesion and temperature resistance, and achieve the best comprehensive performance.

[0021] In some embodiments of the present invention, the first epoxy resin includes AFG-90 epoxy resin; and / or, the second epoxy resin includes AG-80 epoxy resin; and / or, the third epoxy resin includes AG-602 epoxy resin.

[0022] In some embodiments of the present invention, the weight ratio of AFG-90 epoxy resin, AG-80 epoxy resin and AG-602 epoxy resin in the hyperbranched bisphenol A epoxy resin composition is 1:(0.2-5):(0.2-5).

[0023] The present invention optimizes the usage ratio of each component in the hyperbranched bisphenol A epoxy resin composition. When the weight ratio of the AFG-90 epoxy resin, the AG-80 epoxy resin and the AG-602 epoxy resin is within the above range, the functional groups and hyperbranched structures in each epoxy resin can better play their roles while maintaining the easy processability of the resin, thereby further improving the corrosion resistance and wet heat stability of the coating prepared by the coating.

[0024] In some embodiments of the present invention, the components of the hyperbranched bisphenol A epoxy resin composition include, by weight: 25 to 55 parts of AFG-90 epoxy resin, 25 to 55 parts of AG-80 epoxy resin and 25 to 60 parts of AG-602 epoxy resin.

[0025] The present invention optimizes the formula dosage of three components in a hyperbranched bisphenol A epoxy resin composition. Through a reasonable dosage ratio, the combined use of the three hyperbranched bisphenol A epoxy resins can achieve better improvement of the water resistance of the resin coating, and is also helpful to further reduce internal stress, improve adhesion and temperature resistance, so that the comprehensive performance of the coating is optimized.

[0026] In some embodiments of the present invention, the curing agent composition includes an organic amine curing agent, a phenol curing agent and a metal salt curing agent.

[0027] The present invention cures and modifies the epoxy resin coating by adjusting the formula of the curing agent composition components (including organic amine curing agents, phenolic curing agents and metal salt curing agents), so that the cured epoxy resin coating has the effects of low processing temperature, enhanced heat resistance, enhanced anti-permeability and enhanced anti-rust performance. In the combination of the curing agent composition of the coating of the present invention, the organic amine curing agent contains NH bonds, which can react with the epoxy groups of the epoxy resin, wherein the primary amine groups react with the epoxy groups to produce secondary amines and hydroxyl groups, thereby improving the heat resistance stability of the cross-linked network; the phenolic hydroxyl groups of the phenolic curing agent react with the epoxy groups to produce ether bonds and hydroxyl groups, wherein the ether bonds can improve the overall flexibility of the epoxy resin coating; the metal salt curing agent, as an auxiliary curing agent, can improve the anti-rust performance of the epoxy coating. In the coating component of the present invention, the bisphenol A group in the epoxy resin composition can provide adhesion between the coating and the substrate material, and the hyperbranched structure can provide multiple cross-linkable sites to form a high-density cross-linked network. Therefore, the epoxy resin composition is further cured using the above-mentioned curing agent composition, and ultimately the corrosion resistance, adhesion performance and high temperature resistance of the coating are significantly improved, thereby meeting the application requirements in extremely harsh environments such as high humidity and heat, acid and alkali corrosion, etc.

[0028] In some embodiments of the present invention, the organic amine curing agent includes at least one of 4,4'-(1,4-phenylenedioxy) dianiline, 4,4'-bis(4-aminophenoxy) diphenyl sulfone, 4,4'-bis(3-aminophenoxy) diphenyl sulfone, 4,4'-diaminodiphenyl sulfone, and 4,4'-diaminodiphenylmethane.

[0029] The organic amine curing agent used in the present invention contains NH bonds and can react with the epoxy groups of the epoxy resin. For example, the reaction of primary amines with epoxy groups can produce secondary amines and hydroxyl groups. The epoxy resin coating cured with the organic amine curing agent has high heat resistance, but is very brittle.

[0030] In some embodiments of the present invention, the phenolic curing agent includes at least one of cardanol and phenolic resin.

[0031] The phenolic curing agent used in the present invention contains a phenol group, and the phenolic hydroxyl group thereof reacts with the epoxy group to generate an ether bond and a hydroxyl group. The epoxy resin coating cured by the phenolic curing agent has a low processing temperature and good flexibility, but insufficient heat resistance.

[0032] In some embodiments of the present invention, the metal salt curing agent includes dithiophosphoric acid-O,O-di-C 1-14 -Alkyl ester zinc salt.

[0033] The metal salt curing agent used in the present invention is a zinc-modified organic curing agent, which is used as an auxiliary curing agent to enhance the anti-rust performance of the epoxy coating.

[0034] The present invention utilizes the combination of the above-mentioned curing agents to achieve the effect that the cured epoxy resin coating has low processing temperature, enhanced heat resistance, enhanced anti-permeability, and enhanced rust resistance. In the combination of the curing agent composition of the coating of the present invention, the organic amine curing agent contains NH bonds, which can react with the epoxy group of the epoxy resin, wherein the primary amine group reacts with the epoxy group to produce secondary amines and hydroxyls, thereby improving the heat resistance stability of the cross-linked network; the phenolic hydroxyl group of the phenolic curing agent reacts with the epoxy group to produce ether bonds and hydroxyls, wherein the ether bonds can improve the overall flexibility of the epoxy resin coating; the metal salt curing agent is used as an auxiliary curing agent to improve the rust resistance of the epoxy coating. Therefore, the present invention utilizes a combination of organic amine curing agents, phenolic curing agents, and metal salt curing agents to cure hyperbranched bisphenol A epoxy resin, which can significantly improve the corrosion resistance and high temperature resistance of the coating, thereby meeting the application requirements in extremely harsh environments such as high humidity and heat, acid and alkali corrosion, etc.

[0035] In some embodiments of the present invention, the curing agent composition includes, by weight: 8 to 14 parts of an organic amine curing agent, 4 to 10 parts of a phenolic curing agent, and 1 to 19 parts of a metal salt curing agent.

[0036] In some embodiments of the present invention, the raw material components of the coating further include: 0.1 to 100 parts of filler, by weight.

[0037] The present invention can adjust the bonding strength of the resin adhesive and / or the high temperature resistance and / or give the material other known excellent properties and / or control the cost by adding fillers.

[0038] In some embodiments of the present invention, the filler is selected from at least one of carbon black, graphite, carbon nanotubes, activated carbon, alumina, silica, mica, boron nitride, calcium silicate, benzoin, titanium dioxide, MXene, glass microspheres, quartz sand, iron powder, iron salt, ferric chloride, ferrous chloride, cobalt chloride, nickel chloride, sodium tripolyphosphate, mica iron oxide, aluminum phosphate, glass flakes, zinc phosphate, and calcium phosphate.

[0039] Different effects can be achieved by adding different types of fillers. For example, benzoin in the filler can be used as a degassing agent, silica or alumina can be used as a reinforcing agent and a cost reducer, and sodium tripolyphosphate, mica iron oxide, aluminum phosphate, glass flakes, zinc phosphate or calcium phosphate can be used as a rust remover.

[0040] In the present invention, the raw material components of the coating may also include other additives, such as defoamers, leveling agents, thixotropic agents, coupling agents, anti-settling agents, dispersants, etc., and the above-mentioned defoamers, leveling agents, thixotropic agents, coupling agents, anti-settling agents, dispersants, etc. can be reasonably selected from any common types in the art according to actual conditions, and no limitation is made here.

[0041] A second aspect of the present invention provides a method for preparing the above-mentioned coating, comprising the following steps:

[0042] The raw material components are mixed according to weight proportions, heated and cured, and crushed to obtain the coating.

[0043] The preparation method provided by the invention has the characteristics of simple process, mild reaction conditions, easy operation and high production efficiency, and is suitable for large-scale production application.

[0044] In some embodiments of the present invention, the heating and curing process is: heating to 30-120°C and curing for 10-60 minutes. The heating and curing process is a gradient temperature rise curing, and the gradient temperature rise curing includes two stages: heating to 30-100°C and curing for 5-30 minutes, and then heating to 80-120°C and curing for 5-30 minutes.

[0045] In some embodiments of the present invention, the pulverizing method is to use a grinding mill to pulverize.

[0046] In some embodiments of the present invention, the coating is epoxy resin sintered powder.

[0047] In some embodiments of the present invention, after the epoxy resin sintered powder is obtained, it can be directly used as a coating powder for electrostatic spraying of a metal substrate; it can also be prepared into a slurry and then coated.

[0048] The third aspect of the present invention provides the use of the above-mentioned coating or the coating prepared by the above-mentioned preparation method in coating of metal substrates.

[0049] The coating obtained by the present invention has the characteristics of high heat resistance, easy processing and high adhesion. When applied to metal substrate coating, the formed coating has high density, strong anti-penetration and high heat resistance, and can meet the application requirements in extremely harsh environments.

[0050] In some embodiments of the present invention, the metal substrate includes a single metal and a metal alloy, such as tinplate, titanium alloy, stainless steel, and the like.

[0051] A fourth aspect of the present invention provides an anti-corrosion coating, wherein the raw materials for preparing the anti-corrosion coating include the above-mentioned coating or the coating prepared by the above-mentioned preparation method.

[0052] The anticorrosive coating provided by the present invention is obtained by coating the aforementioned coating, and therefore also has the technical effects of the coating described above. The present invention applies the aforementioned coating to a metal substrate to form a coating with high density, strong anti-permeability and high heat resistance, which can meet the application requirements in extremely harsh environments.

[0053] In some embodiments of the present invention, the coating can be prepared into a slurry, and then evenly coated on the surface of the metal substrate by scraping, spin coating or spraying, and then cured to obtain the anti-corrosion coating. The coating method can be conventional methods in the art and is not limited here.

[0054] In some embodiments of the present invention, the thickness of the anti-corrosion coating is 100-500 μm. Including any numerical value and all ranges and any sub-ranges therein. For example, including 100 μm, 150 μm, 200 μm, 250 μm, 300 μm, 400 μm and 500 μm. Therefore, when the thickness of the anti-corrosion coating is within the above range, it has a good protective effect and is not easy to fall off.

[0055] A fifth aspect of the present invention provides a coated product, comprising a metal substrate and a coating located on the surface of the metal substrate; the coating is the above-mentioned anti-corrosion coating.

[0056] In some embodiments of the present invention, the metal substrate includes a single metal and a metal alloy, such as tinplate, titanium alloy, stainless steel, and the like.

[0057] A sixth aspect of the present invention provides a household appliance, wherein the raw materials for preparing the household appliance include the above-mentioned coating or the above-mentioned anti-corrosion coating.

[0058] In some embodiments of the present invention, the household electrical appliances include refrigeration appliances, air conditioners, cleaning appliances, kitchen appliances, electric heating appliances, audio-visual appliances and water heaters.

[0059] A seventh aspect of the present invention provides the use of the above-mentioned coating or the above-mentioned anti-corrosion coating in a hot and humid environment or an acid-base environment.

[0060] According to some embodiments of the present invention, the hot and humid environment refers to an environment temperature higher than 35° C. and an environment relative humidity higher than 70%.

[0061] Other features and advantages of the present invention will be described in the following description, and partly become apparent from the description, or understood by practicing the present invention. The purpose and other advantages of the present invention can be realized and obtained by the structures specifically pointed out in the description and claims. DETAILED DESCRIPTION

[0062] The following will be combined with the embodiments to clearly and completely describe the concept of the present invention and the technical effects produced, so as to fully understand the purpose, characteristics and effects of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of them. Based on the embodiments of the present invention, other embodiments obtained by those skilled in the art without creative work are all within the scope of protection of the present invention.

[0063] In the description of the present invention, the description with reference to the terms "one embodiment", "some embodiments", "illustrative embodiments", "examples", "specific examples", or "some examples" means that the specific features, structures, materials or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the present invention. In this specification, the schematic representation of the above terms does not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described may be combined in any one or more embodiments or examples in a suitable manner.

[0064] In the description of the present invention, unless otherwise specified, the numerical range "a to b" represents an abbreviation of any real number combination between a and b, wherein a and b are real numbers. Unless otherwise specified, each reaction or operation step may be performed in sequence or not. Preferably, the reaction method of the present invention is performed in sequence.

[0065] If no specific techniques or conditions are specified in the following examples, the techniques or conditions described in the literature in the art or the product instructions are used. All reagents or instruments without manufacturer specified are conventional products that can be purchased commercially.

[0066] The first aspect of the present invention provides a coating, wherein the raw material components of the coating include, by weight: 50 to 200 parts of a hyperbranched bisphenol A epoxy resin composition, 1 to 100 parts of a curing agent composition;

[0067] The hyperbranched bisphenol A epoxy resin contains bisphenol A groups, glycidyl amine groups, glycidyl ether groups and aliphatic ring groups.

[0068] The embodiment of the present invention realizes the modification of the corrosion resistance of epoxy resin coating by using hyperbranched bisphenol A epoxy resin; the bisphenol A group contained in the hyperbranched bisphenol A epoxy resin can provide the adhesion between the coating and the substrate material, so that the coating and the substrate are not easy to separate during the bonding process; the glycidylamine group in the hyperbranched bisphenol A epoxy resin is used to help improve the heat resistance of the epoxy resin after curing; the combination of glycidyl ether group and glycidylamine group can effectively improve the heat resistance of the epoxy resin after curing while maintaining the easy processability of the resin; the aliphatic ring group helps to improve the mechanical properties of the epoxy resin after curing; in addition, the large conjugation effect formed between the high benzene ring group content of the hyperbranched bisphenol A epoxy resin helps to slow down the penetration of corrosive media; and its hyperbranched structure can provide multiple cross-linkable sites, which can form a high-density cross-linked network in the cross-linked network of the coating, thereby improving the heat resistance of the coating. Therefore, the embodiments of the present invention modify the coating by using a hyperbranched bisphenol A epoxy resin containing multiple groups, so as to achieve the effects of lowering the processing temperature of the epoxy resin coating, enhancing heat resistance, enhancing anti-permeability or enhancing anti-rust performance, and meet the application requirements in extremely harsh environments such as high humidity and heat, acid and alkali corrosion, etc.

[0069] In some embodiments of the present invention, the raw material components of the coating include, by weight: 80 to 160 parts of a hyperbranched bisphenol A epoxy resin composition and 10 to 40 parts of a curing agent composition.

[0070] The present invention optimizes the formula and dosage of two main components in the coating, further improves the curing effect of the curing agent composition on the hyperbranched bisphenol A epoxy resin composition, helps the functional groups and hyperbranched structures in the hyperbranched bisphenol A epoxy resin to play a role, and achieves better improvement effects on the epoxy resin coating in terms of lowering the processing temperature, enhancing the heat resistance, enhancing the anti-permeability or enhancing the anti-rust performance.

[0071] In some embodiments of the present invention, the raw material components of the coating include, by weight: 90-140 parts of a hyperbranched bisphenol A epoxy resin composition and 15-30 parts of a curing agent composition.

[0072] In some embodiments of the present invention, the raw material components of the coating include, by weight: 100-130 parts of a hyperbranched bisphenol A epoxy resin composition and 20-28 parts of a curing agent composition.

[0073] In some embodiments of the present invention, the hyperbranched bisphenol A epoxy resin includes a first epoxy resin, a second epoxy resin and a third epoxy resin;

[0074] The first epoxy resin contains bisphenol A groups and glycidylamine groups;

[0075] The second epoxy resin contains bisphenol A groups, glycidyl ether groups and glycidyl amine groups;

[0076] The third epoxy resin contains a bisphenol A group and an aliphatic ring group.

[0077] Each epoxy resin in the hyperbranched bisphenol A epoxy resin composition of the present invention contains functional groups respectively. These epoxy resins interact with each other, and each functional group plays a synergistic role, so that the finally formed epoxy resin coating has better resistance to moisture and heat and acid and alkali corrosion.

[0078] In some embodiments of the present invention, the epoxide value of the hyperbranched bisphenol A epoxy resin is 0.6 to 1.2.

[0079] The invention helps to promote the function of each functional group in the epoxy resin composition by selecting a hyperbranched bisphenol A epoxy resin with a higher epoxy value. Combined with the hyperbranched structure in the hyperbranched bisphenol A epoxy resin, a better high-density cross-linked network can be formed in the coating, thereby improving the heat resistance and corrosion resistance of the coating prepared by the coating.

[0080] In some embodiments of the present invention, the epoxide value of the hyperbranched bisphenol A epoxy resin is 0.7 to 1.15.

[0081] In some embodiments of the present invention, the epoxy value of the first epoxy resin is 0.7-1.05; and / or, the epoxy value of the second epoxy resin is 0.6-0.95; and / or, the epoxy value of the third epoxy resin is 0.9-1.2.

[0082] In some embodiments of the present invention, the epoxy value of the first epoxy resin is 0.8-0.95; and / or, the epoxy value of the second epoxy resin is 0.7-0.85; and / or, the epoxy value of the third epoxy resin is 0.95-1.15.

[0083] In some embodiments of the present invention, the hyperbranched bisphenol A epoxy resin includes AFG-90 epoxy resin, AG-80 epoxy resin and AG-602 epoxy resin.

[0084] The embodiment of the present invention optimizes the components of the hyperbranched bisphenol A epoxy resin composition, and selects AFG-90 epoxy resin, AG-80 epoxy resin and AG-602 epoxy resin for combination, wherein the AFG-90 epoxy resin has an epoxy value of 0.85-0.9, contains bisphenol A groups and glycidylamine groups in its structure, and because of its high epoxy value and nitrogen atoms, it helps to improve the heat resistance of the epoxy resin after curing; the AG-80 epoxy resin has an epoxy value of 0.75-0.8, contains bisphenol A groups, glycidyl ether and glycidylamine groups in its structure, has a high epoxy value and contains phenyl ether bonds, can effectively improve the heat resistance of the epoxy resin after curing while maintaining the easy processability of the resin; the AG-602 epoxy resin has an epoxy value of 1.06, contains bisphenol A groups and aliphatic ring groups in its structure, has a high epoxy value and a high degree of branching, and can effectively improve the mechanical properties of the epoxy resin after curing. The combined use of three hyperbranched bisphenol A epoxy resins can enhance the water resistance of the resin, reduce internal stress, improve adhesion and temperature resistance, and achieve the best comprehensive performance.

[0085] In some embodiments of the present invention, the first epoxy resin includes AFG-90 epoxy resin; and / or, the second epoxy resin includes AG-80 epoxy resin; and / or, the third epoxy resin includes AG-602 epoxy resin.

[0086] In some embodiments of the present invention, the weight ratio of AFG-90 epoxy resin, AG-80 epoxy resin and AG-602 epoxy resin in the hyperbranched bisphenol A epoxy resin composition is 1:(0.2-5):(0.2-5).

[0087] The embodiment of the present invention optimizes the usage ratio of each component in the hyperbranched bisphenol A epoxy resin composition. When the weight ratio of AFG-90 epoxy resin, AG-80 epoxy resin and AG-602 epoxy resin is within the above range, the functional groups and hyperbranched structures in each epoxy resin can play a better role while maintaining the easy processability of the resin, thereby further improving the corrosion resistance and wet heat stability of the coating prepared by the coating. In addition, the water resistance of the resin coating can be improved, and it is also helpful to further reduce internal stress, improve adhesion and high temperature resistance.

[0088] In some embodiments of the present invention, the weight ratio of AFG-90 epoxy resin, AG-80 epoxy resin and AG-602 epoxy resin in the hyperbranched bisphenol A epoxy resin composition is 1:(0.3~3):(0.3~3).

[0089] In some embodiments of the present invention, the weight ratio of AFG-90 epoxy resin, AG-80 epoxy resin and AG-602 epoxy resin in the hyperbranched bisphenol A epoxy resin composition is 1:(0.5~2):(0.5~2).

[0090] In some embodiments of the present invention, the components of the hyperbranched bisphenol A epoxy resin composition include, by weight: 25 to 55 parts of AFG-90 epoxy resin, 25 to 55 parts of AG-80 epoxy resin and 25 to 60 parts of AG-602 epoxy resin.

[0091] In some embodiments of the present invention, the components of the hyperbranched bisphenol A epoxy resin composition include, by weight: 30 to 50 parts of AFG-90 epoxy resin, 30 to 50 parts of AG-80 epoxy resin and 30 to 55 parts of AG-602 epoxy resin.

[0092] The embodiment of the present invention optimizes the formula dosage of the three components in the hyperbranched bisphenol A epoxy resin composition. Through a reasonable ratio of the dosage, the combined use of the three hyperbranched bisphenol A epoxy resins can also achieve better improvement of the water resistance of the resin coating, and also help to further reduce internal stress, improve adhesion and high temperature resistance, thereby optimizing the comprehensive performance of the coating.

[0093] In some embodiments of the present invention, the curing agent composition includes an organic amine curing agent, a phenol curing agent and a metal salt curing agent.

[0094] The embodiment of the present invention adjusts the formula of the curing agent composition components (including organic amine curing agents, phenolic curing agents and metal salt curing agents) to cure and modify the epoxy resin coating, so that the cured epoxy resin coating has the effects of low processing temperature, enhanced heat resistance, enhanced anti-permeability and enhanced anti-rust performance. In the combination of the curing agent composition of the coating of the embodiment of the present invention, the organic amine curing agent contains NH bonds, which can react with the epoxy group of the epoxy resin, wherein the primary amine group reacts with the epoxy group to produce secondary amines and hydroxyl groups, thereby improving the heat resistance stability of the cross-linked network; the phenolic hydroxyl group of the phenolic curing agent reacts with the epoxy group to produce ether bonds and hydroxyl groups, wherein the ether bonds can improve the overall flexibility of the epoxy resin coating; the metal salt curing agent, as an auxiliary curing agent, can improve the anti-rust performance of the epoxy coating. In the coating components of the embodiments of the present invention, the bisphenol A group in the epoxy resin composition can provide adhesion between the coating and the substrate material, and the hyperbranched structure can provide multiple cross-linkable sites to form a high-density cross-linked network. Therefore, the epoxy resin composition is further cured using the above-mentioned curing agent composition, and ultimately the corrosion resistance, adhesion performance and high temperature resistance of the coating are significantly improved, thereby meeting the application requirements in extremely harsh environments such as high humidity and heat, acid and alkali corrosion, etc.

[0095] In some embodiments of the present invention, the organic amine curing agent includes at least one of 4,4'-(1,4-phenylenedioxy) dianiline, 4,4'-bis(4-aminophenoxy) diphenyl sulfone, 4,4'-bis(3-aminophenoxy) diphenyl sulfone, 4,4'-diaminodiphenyl sulfone, and 4,4'-diaminodiphenylmethane.

[0096] In some embodiments of the present invention, the organic amine curing agent is selected from at least one of 4,4'-(1,4-phenylenedioxy) dianiline, 4,4'-bis(4-aminophenoxy) diphenyl sulfone, 4,4'-bis(3-aminophenoxy) diphenyl sulfone, 4,4'-diaminodiphenyl sulfone and 4,4'-diaminodiphenylmethane.

[0097] The organic amine curing agent used in the embodiment of the present invention contains NH bonds, which can react with the epoxy groups of the epoxy resin. For example, the reaction of primary amines with epoxy groups can produce secondary amines and hydroxyl groups. The epoxy resin coating cured with the organic amine curing agent has high heat resistance, but is very brittle.

[0098] In some embodiments of the present invention, the phenolic curing agent includes at least one of cardanol and phenolic resin.

[0099] In some embodiments of the present invention, the phenolic curing agent is selected from at least one of cardanol and phenolic resin.

[0100] The phenolic curing agent used in the embodiment of the present invention contains a phenol group, and the phenolic hydroxyl group thereof reacts with the epoxy group to produce an ether bond and a hydroxyl group. The epoxy resin coating cured by the phenolic curing agent has a low processing temperature and good flexibility, but insufficient heat resistance.

[0101] In some embodiments of the present invention, the metal salt curing agent includes dithiophosphoric acid-O,O-di-C 1-14 -Alkyl ester zinc salt.

[0102] In some embodiments of the present invention, the metal salt curing agent is dithiophosphoric acid-O,O-di-C 1-14 -Alkyl ester zinc salt.

[0103] The metal salt curing agent used in the embodiment of the present invention is a zinc-modified organic curing agent, which is used as an auxiliary curing agent to enhance the anti-rust performance of the epoxy coating.

[0104] The embodiment of the present invention utilizes the combination of the above-mentioned curing agents to achieve the effect that the cured epoxy resin coating has low processing temperature, enhanced heat resistance, enhanced anti-permeability, and enhanced anti-rust performance. In the combination of the curing agent composition of the coating of the embodiment of the present invention, the organic amine curing agent contains NH bonds, which can react with the epoxy group of the epoxy resin, wherein the primary amine group reacts with the epoxy group to produce secondary amines and hydroxyls, thereby improving the heat-resistant stability of the cross-linked network; the phenolic hydroxyl group of the phenolic curing agent reacts with the epoxy group to produce ether bonds and hydroxyls, wherein the ether bonds can improve the overall flexibility of the epoxy resin coating; the metal salt curing agent is used as an auxiliary curing agent to improve the anti-rust performance of the epoxy coating. Therefore, the embodiment of the present invention utilizes a combination of organic amine curing agents, phenolic curing agents, and metal salt curing agents to cure hyperbranched bisphenol A epoxy resin, which can significantly improve the corrosion resistance and high temperature resistance of the coating, thereby meeting the application requirements in extremely harsh environments such as high humidity and heat, acid and alkali corrosion.

[0105] In some embodiments of the present invention, the curing agent composition comprises, by weight: 8 to 14 parts of an organic amine curing agent, 4 to 10 parts of a phenolic curing agent, and 1 to 19 parts of a metal salt curing agent.

[0106] In some embodiments of the present invention, the curing agent composition comprises, by weight: 9 to 13 parts of an organic amine curing agent, 4 to 9 parts of a phenolic curing agent, and 2 to 15 parts of a metal salt curing agent.

[0107] In some embodiments of the present invention, the raw material components of the coating further include: 0.1 to 100 parts of filler, by weight.

[0108] In some embodiments of the present invention, the raw material components of the coating further include: 0.1 to 20 parts of filler, by weight.

[0109] In some embodiments of the present invention, the raw material components of the coating further include: 0.1 to 10 parts of filler, by weight.

[0110] In some embodiments of the present invention, the filler is selected from at least one of carbon black, graphite, carbon nanotubes, activated carbon, alumina, silica, mica, boron nitride, calcium silicate, benzoin, titanium dioxide, MXene, glass microspheres, quartz sand, iron powder, iron salt, ferric chloride, ferrous chloride, cobalt chloride, nickel chloride, sodium tripolyphosphate, mica iron oxide, aluminum phosphate, glass flakes, zinc phosphate, and calcium phosphate.

[0111] The embodiments of the present invention can adjust the bonding strength of the resin adhesive and / or its high temperature resistance and / or impart other known excellent properties to the material and / or control the cost by adding fillers.

[0112] For example, benzoin in the filler can be used as a degassing agent, silica or alumina can be used as a reinforcing agent and a cost-reducing agent, and sodium tripolyphosphate, mica iron oxide, aluminum phosphate, glass flakes, zinc phosphate or calcium phosphate can be used as a rust remover.

[0113] In an embodiment of the present invention, the raw material components of the coating may also include other additives, such as defoamers, leveling agents, thixotropic agents, coupling agents, anti-settling agents, dispersants, etc., and the above-mentioned defoamers, leveling agents, thixotropic agents, coupling agents, anti-settling agents, dispersants, etc. can be reasonably selected from any common types in the art according to actual conditions, and no limitation is made here.

[0114] A second aspect of the present invention provides a method for preparing the above-mentioned coating, comprising the following steps:

[0115] The raw material components are mixed according to weight proportions, heated and cured, and crushed to obtain the coating.

[0116] The preparation method provided by the embodiment of the present invention has the characteristics of simple process, mild reaction conditions, easy operation and high production efficiency, and is suitable for large-scale production application.

[0117] In some embodiments of the present invention, the mixing and the heating and curing are performed in an inert atmosphere or an air atmosphere.

[0118] In some embodiments of the present invention, the mixing and the heat curing are performed under an inert atmosphere.

[0119] In some embodiments of the present invention, the heating and curing process is: heating to 30-120°C and curing for 10-60 minutes. The heating and curing process is gradient temperature rise curing, and the gradient temperature rise curing includes two stages: heating to 30-100°C and curing for 5-30 minutes, and then heating to 80-120°C and curing for 5-30 minutes.

[0120] In some embodiments of the present invention, the heating and curing process is: heating to 30-100°C and curing for 10-60 minutes. The heating and curing process is gradient temperature rise curing, and the gradient temperature rise curing includes two stages: heating to 30-80°C and curing for 5-30 minutes, and then heating to 80-100°C and curing for 5-30 minutes.

[0121] In some embodiments of the present invention, the pulverizing method is to use a grinding mill to pulverize.

[0122] In some embodiments of the present invention, the coating is epoxy resin sintered powder.

[0123] In some embodiments of the present invention, after the epoxy resin sintered powder is obtained, it can be directly used as a coating powder for electrostatic spraying of a metal substrate; it can also be prepared into a slurry and then coated.

[0124] The third aspect of the present invention provides the use of the above-mentioned coating or the coating prepared by the above-mentioned preparation method in coating of metal substrates.

[0125] The coating obtained in the embodiment of the present invention has the characteristics of high heat resistance, easy processing and high adhesion. When applied to metal substrate coating, the formed coating has high density, strong anti-penetration and high heat resistance, which can meet the application requirements in extremely harsh environments.

[0126] A fourth aspect of the present invention provides an anti-corrosion coating, wherein the raw materials for preparing the anti-corrosion coating include the above-mentioned coating or the coating prepared by the above-mentioned preparation method.

[0127] The anti-corrosion coating provided by the embodiment of the present invention is obtained by coating the aforementioned coating, and therefore also has the technical effect of the coating described above. The embodiment of the present invention applies the aforementioned coating to the metal substrate, and the formed coating has high density, strong anti-permeability and high heat resistance, which can meet the application requirements in extremely harsh environments.

[0128] In some embodiments of the present invention, the coating can be prepared into a slurry, and then evenly coated on the surface of the metal substrate by scraping, spin coating or spraying, and then cured to obtain the anti-corrosion coating. The coating method can be conventional methods in the art and is not limited here.

[0129] In some embodiments of the present invention, the thickness of the anti-corrosion coating is 100-500 μm. Including any numerical value and all ranges and any sub-ranges therein. For example, including 100 μm, 150 μm, 200 μm, 250 μm, 300 μm, 400 μm and 500 μm. Therefore, when the thickness of the anti-corrosion coating is within the above range, it has a good protective effect and is not easy to fall off.

[0130] A fifth aspect of the present invention provides a coated product, comprising a metal substrate and a coating located on the surface of the metal substrate; the coating is the above-mentioned anti-corrosion coating.

[0131] In some embodiments of the present invention, the metal substrate includes a single metal and a metal alloy, such as tinplate, titanium alloy, stainless steel, and the like.

[0132] A sixth aspect of the present invention is a household appliance, wherein the raw materials for preparing the household appliance include the above-mentioned coating or the above-mentioned anti-corrosion coating.

[0133] In some embodiments of the present invention, the household appliances include refrigeration appliances (such as household refrigerators, cold drink machines, etc.), air conditioners (such as room air conditioners, electric fans, ventilation fans, hot and cold air blowers, air dehumidifiers, cold air blowers, humidifiers, etc.), cleaning appliances (such as washing machines, dryers, electric irons, vacuum cleaners, floor waxers, sweeping robots, etc.), kitchen appliances (such as electric stoves, microwave ovens, induction cookers, electric ovens, rice cookers, dishwashers, food processors, etc.), electric heating appliances (such as space heaters), audio and video appliances (such as micro projectors, televisions, radios, tape recorders, video recorders, cameras, combination audio systems, etc.), and water heaters (such as air-energy water heaters, solar water heaters, electric water heaters, gas water heaters, etc.).

[0134] A seventh aspect of the present invention provides the use of the above-mentioned coating or the above-mentioned anti-corrosion coating in a hot and humid environment or an acidic and alkaline environment.

[0135] According to some embodiments of the present invention, the hot and humid environment refers to an environment temperature higher than 35° C. and an environment relative humidity higher than 70%.

[0136] Furthermore, some of the raw materials used in the examples and comparative examples of the present invention come from the following sources:

[0137] Hyperbranched bisphenol A epoxy resin: AFG-90 epoxy resin, AG-80 epoxy resin, AG-602 epoxy resin were purchased from Shanghai Huayi Resin Co., Ltd.

[0138] Organic amine curing agents: 4,4'-(1,4-phenylenedioxy) dianiline, 4,4'-bis(4-aminophenoxy) diphenyl sulfone, and 4,4'-diaminodiphenylmethane were purchased from Shanghai Aladdin Biochemical Technology Co., Ltd.

[0139] Phenolic curing agent: Cardanol and phenolic resin were purchased from Beijing Bailingwei Technology Co., Ltd.

[0140] Metal salt curing agent: dithiophosphoric acid-O,O-di-C 1-14 -Alkyl ester zinc salt; CAS No. 68649-42-3; commercially available.

[0141] Benzoin was purchased from Shanghai Aladdin Biochemical Technology Co., Ltd.

[0142] Other features and advantages of the present invention will be described in the following description, and partly become apparent from the description, or understood by practicing the present invention. The purpose and other advantages of the present invention can be realized and obtained by the structures specifically pointed out in the description and claims.

[0143] Example 1

[0144] This embodiment provides a coating, and uses the coating to prepare a coating.

[0145] The raw materials for preparing the coating of this embodiment are calculated by weight: 125 parts of epoxy resin composition, 22 parts of curing agent composition, and 1 part of benzoin; wherein the epoxy resin composition is 45 parts of AFG-90 epoxy resin, 45 parts of AG-80 epoxy resin, and 35 parts of AG-602 epoxy resin; the curing agent composition is 10 parts of 4,4'-(1,4-phenylenedioxy) dianiline, 5 parts of cardanol, and dithiophosphoric acid-O,O-di-C 1-14 -7 parts of alkyl ester zinc salt. Among them, the epoxy value of AFG-90 epoxy resin is 0.85-0.9, the epoxy value of AG-80 epoxy resin is 0.75-0.8, and the epoxy value of AG-602 epoxy resin is 1.06.

[0146] The above raw materials were mixed by weight, cured at 80°C for 10 minutes and 100°C for 10 minutes under an inert atmosphere. The cured prepolymer resin was then crushed using an ACM grinder to obtain a coating powder. The coating powder was prepared into a slurry, sprayed on a tinplate metal substrate, and then thermally cured in an air environment at 230°C for 15 minutes to form a final coating.

[0147] The thickness of the coating is 250 μm.

[0148] Example 2

[0149] The difference between this embodiment and embodiment 1 is that the formula of the coating is different. In this embodiment, the raw materials for preparation are calculated by weight as follows: 105 parts of epoxy resin composition, 23 parts of curing agent composition, and 0.1 parts of benzoin; wherein the epoxy resin composition is 35 parts of AFG-90 epoxy resin, 35 parts of AG-80 epoxy resin, and 35 parts of AG-602 epoxy resin, and the curing agent composition is 12 parts of 4,4'-bis(4-aminophenoxy)diphenyl sulfone, 8 parts of cardanol, and dithiophosphoric acid-O,O-di-C 1-14 -3 parts of alkyl ester zinc salt. Other contents are the same as in Example 1.

[0150] Example 3

[0151] The difference between this embodiment and embodiment 1 is that the formula of the coating is different. In this embodiment, the raw materials for preparation are calculated by weight as follows: 120 parts of epoxy resin composition, 25 parts of curing agent composition, and 10 parts of benzoin; wherein the epoxy resin composition is 35 parts of AFG-90 epoxy resin, 35 parts of AG-80 epoxy resin, and 50 parts of AG-602 epoxy resin, and the curing agent composition is 10 parts of 4,4'-diaminodiphenylmethane, 5 parts of phenolic resin, and dithiophosphoric acid-O,O-di-C 1-14 -10 parts of alkyl ester zinc salt. Other contents are the same as those in Example 1.

[0152] Example 4

[0153] The difference between this embodiment and embodiment 1 is that the epoxy resin composition of this embodiment is 20 parts of AFG-90 epoxy resin, 45 parts of AG-80 epoxy resin and 60 parts of AG-602 epoxy resin. The rest is the same as embodiment 1.

[0154] Example 5

[0155] The difference between this embodiment and embodiment 1 is that the epoxy resin composition of this embodiment is 60 parts of AFG-90 epoxy resin, 45 parts of AG-80 epoxy resin and 20 parts of AG-602 epoxy resin. The rest is the same as embodiment 1.

[0156] Example 6

[0157] The difference between this embodiment and embodiment 1 is that the epoxy resin composition of this embodiment is 45 parts of AFG-90 epoxy resin, 20 parts of AG-80 epoxy resin and 60 parts of AG-602 epoxy resin. The rest is the same as embodiment 1.

[0158] Comparative Example 1

[0159] The difference between this comparative example and Example 1 is that the formula of the coating is different. In this comparative example, the raw materials for preparation are calculated by weight as follows: 80 parts of epoxy resin composition, 22 parts of curing agent composition, and 1 part of benzoin; wherein the epoxy resin composition is 45 parts of AG-80 epoxy resin and 35 parts of AG-602 epoxy resin, and does not contain AG-90 epoxy resin; the curing agent composition is 10 parts of 4,4'-(1,4-phenylenedioxy) dianiline, 5 parts of cardanol, and dithiophosphoric acid-O,O-di-C 1-14 -7 parts of alkyl ester zinc salt. Other contents are the same as those in Example 1.

[0160] Comparative Example 2

[0161] The difference between this comparative example and Example 1 is that the formula of the coating is different. In this comparative example, the raw materials for preparation are calculated by weight as follows: 85 parts of epoxy resin composition, 22 parts of curing agent composition, and 1 part of benzoin; wherein the epoxy resin composition is 35 parts of AFG-90 epoxy resin and 50 parts of AG-602 epoxy resin, and does not contain AG-80 epoxy resin; the curing agent composition is 10 parts of 4,4'-(1,4-phenylenedioxy) dianiline, 5 parts of cardanol, and dithiophosphoric acid-O,O-di-C 1-14 -7 parts of alkyl ester zinc salt. Other contents are the same as those in Example 1.

[0162] Comparative Example 3

[0163] The difference between this comparative example and Example 1 is that the formula of the coating is different. In this comparative example, the raw materials for preparation are calculated by weight as follows: 70 parts of epoxy resin composition, 22 parts of curing agent composition, and 1 part of benzoin; wherein the epoxy resin composition is 35 parts of AFG-90 epoxy resin and 35 parts of AG-80 epoxy resin, and does not contain AG-602 epoxy resin; the curing agent composition is 10 parts of 4,4'-(1,4-phenylenedioxy) dianiline, 5 parts of cardanol, and dithiophosphoric acid-O,O-di-C 1-14 -7 parts of alkyl ester zinc salt. Other contents are the same as those in Example 1.

[0164] Comparative Example 4

[0165] The difference between this comparative example and Example 1 is that the curing method is different. In this comparative example, the curing method under an inert atmosphere is to increase the temperature gradually from 120° C. to 150° C. for 20 minutes. The other conditions are the same as those in Example 1.

[0166] Comparative Example 5

[0167] The difference between this comparative example and Example 1 is that tinplate (Shandong Gangzhong Iron and Steel (Tinplate) Co., Ltd.) is used as the test sample, and the surface is not covered with a protective coating.

[0168] Comparative Example 6

[0169] The difference between this comparative example and Example 1 is that tinplate is used as the test sample, the surface of which is sprayed with Degao electrostatic powder coating (article number: RAL1003), and after spraying, it is cured at 230° C. for 1 hour, and the cured coating thickness is 250 μm.

[0170] Test Case

[0171] 1. Pull-off strength test (GB / T 39289-2020; peel strength after metal and plastic bonding): The pull-off strength of the coating in Examples 1 and 2 of the present invention based on a stainless steel substrate was tested.

[0172] Pull-out strength test results: The pull-out strength of the coating on the stainless steel substrate in Example 1 is 3.54 MPa, and the pull-out strength of the coating on the stainless steel substrate in Example 2 is 4.52 MPa. The test results show that the coating formed by the coating has the characteristics of high density and strong adhesion.

[0173] 2. A scratch test was performed on Examples 1 to 6 and Comparative Examples 1 to 6 to evaluate the corrosion resistance of the coating. The method is as follows: take the prepared coating samples, scratch the surface thereof, and the scratch size of the sample surface is consistent. Then, the coating samples are placed in a salt spray test box. After 7 days of salt spray test, the surface of the sample is tested. The test standard is GB / T 10125-2021. The test results are shown in Table 1:

[0174] Table 1 Test results of the salt spray test of the coating samples of the embodiment and the comparative example after 7 days of cross-scratching

[0175]

[0176] The corrosion resistance of the anti-corrosion coating was evaluated through the above cross-scratch experiment, and it was found that there was no obvious change in the surface coating of Examples 1 to 3 before and after the experiment, and there was no corrosion except for the corrosion of the exposed external substrate; the surface coating of Examples 4 to 6 had slight bubbling, indicating that the addition of three hyperbranched bisphenol A epoxy resins in the coating needs to adjust a more appropriate weight ratio to achieve the best coating surface effect; and the surface coating of Comparative Examples 1 to 3 partially fell off, indicating that the epoxy resin coating requires a reasonable combination of three hyperbranched epoxy resins to achieve a better improvement in the corrosion resistance of the coating; the surface coating of Comparative Example 4 had serious shrinkage holes, indicating that the gradient temperature increase method for curing in the preparation process of the coating of the present invention needs to be precisely controlled, otherwise a uniform coating cannot be formed; the cross-scratch of Comparative Example 5 was severely corroded and the corrosion was outwardly derived, and the cross-scratch coating of Comparative Example 6 fell off severely, and the cross-scratch corrosion was severe and the corrosion was outwardly derived. These test results show that the coating prepared by the coating of the present invention is applied to a metal substrate to give it better corrosion resistance.

[0177] 3. Accelerated tests of high temperature resistance and long-term corrosion resistance were performed on Examples 1 to 6 and Comparative Examples 1 to 6. The method is as follows: take the coating samples respectively, soak them in 170°C hot water at 0.65MPa in a high temperature autoclave for 2 days, observe the surface of the samples and detect their electrochemical impedance (test standard GB / T 39482.3-2020). The test results are shown in Table 2:

[0178] Table 2 Accelerated test results of high temperature resistance and long-term corrosion resistance of coating samples of the embodiment and comparative example

[0179]

[0180] For the coatings prepared in the examples and comparative examples, their initial electrochemical impedances were both 10 12 Ω, after being immersed in 170℃ hot water 0.65MPa in a high temperature autoclave for 2 days, the surface coatings of Examples 1 to 3 showed no obvious changes, and the electrochemical impedance only dropped to 10 10 Ω; Examples 4 to 6 show that there are dotted hard foams, and the electrochemical impedance only drops to 10 8 Ω. However, the surface coatings of Comparative Examples 1 to 3 showed point-like bubbles, and the electrochemical impedance dropped to 10 6 Ω; Comparative Example 4 has severe blistering on the surface coating, and the electrochemical impedance drops to 10 6Ω; Comparative Example 5, because the test sample was not protected by coating, its surface was severely corroded. The coating used in Comparative Example 6 had poor high temperature resistance and corrosion resistance, and its surface coating fell off and had no anti-corrosion effect.

[0181] The above test results show that the coating prepared by the scheme of the present invention has good high temperature resistance and long-term corrosion resistance, and can play a good protective role on the substrate; the reasonable ratio of the three hyperbranched bisphenol A epoxy resins in the coating of the scheme of the present invention can realize the corrosion resistance modification of the epoxy resin coating, provide the adhesion of the coating to the substrate material, make the coating and the substrate not easy to separate during the bonding process, and also help to slow down the penetration of the corrosive medium, form a high-density cross-linked network, thereby improving the heat resistance of the coating. Comparative Examples 1 to 3 lack one of the hyperbranched bisphenol A epoxy resins used in the present invention: AFG-90 epoxy resin, AG-80 epoxy resin and AG-602 epoxy resin, which will affect the heat resistance, corrosion resistance and bonding performance of the coating. The gradient temperature rise in the curing process of the coating of Comparative Example 4 is not accurately controlled, and it is difficult to form a uniform coating, which will also affect the protective performance of the coating.

[0182] In summary, the present invention can achieve the effect of reducing the processing temperature of epoxy resin coating, enhancing heat resistance, enhancing permeability or enhancing rust resistance by modifying the coating with hyperbranched bisphenol A epoxy resin. Finally, the present invention uses the above-mentioned hyperbranched bisphenol A epoxy resin to modify the epoxy resin coating, which can significantly improve the corrosion resistance, bonding performance and high temperature resistance of the coating, and can meet the application requirements in extremely harsh environments such as high humidity and heat, acid and alkali corrosion.

[0183] The above is a detailed description of the embodiments of the present invention, but the present invention is not limited to the above embodiments. Various changes can be made within the knowledge of ordinary technicians in the relevant technical field without departing from the purpose of the present invention. In addition, the embodiments of the present invention and the features in the embodiments can be combined with each other without conflict.

Claims

1. A coating, characterized in that: The raw material components of the coating include, by weight: 50 to 200 parts of a hyperbranched bisphenol A epoxy resin composition and 1 to 100 parts of a curing agent composition; Wherein, the hyperbranched bisphenol A epoxy resin composition contains bisphenol A groups, glycidyl amine groups, glycidyl ether groups and aliphatic ring groups; The hyperbranched bisphenol A epoxy resin composition comprises AFG-90 epoxy resin, AG-80 epoxy resin and AG-602 epoxy resin; The weight ratio of AFG-90 epoxy resin, AG-80 epoxy resin and AG-602 epoxy resin in the hyperbranched bisphenol A epoxy resin composition is 1: (0.3-3): (0.3-3); The curing agent composition comprises an organic amine curing agent, a phenol curing agent and a metal salt curing agent; the metal salt curing agent comprises dithiophosphoric acid-O,O-di-C 1-14 - alkyl ester zinc salts; The coating is prepared by a preparation method comprising the following steps: The raw material components are mixed according to weight proportions, heated and cured, and crushed to obtain the coating; The heating and curing process is a gradient temperature rise curing process, which includes two stages: heating to 30-100° C. for curing for 5-30 minutes, and then heating to 80-120° C. for curing for 5-30 minutes.

2. The coating according to claim 1, characterized in that The epoxide value of the hyperbranched bisphenol A epoxy resin composition is 0.6-1.

2.

3. The coating according to claim 1, characterized in that In parts by weight, the components of the hyperbranched bisphenol A epoxy resin composition include: 25 to 55 parts of AFG-90 epoxy resin, 25 to 55 parts of AG-80 epoxy resin and 25 to 60 parts of AG-602 epoxy resin.

4. The coating according to claim 1, characterized in that The organic amine curing agent includes at least one of 4,4'-(1,4-phenylenedioxy) dianiline, 4,4'-bis(4-aminophenoxy) diphenyl sulfone, 4,4'-bis(3-aminophenoxy) diphenyl sulfone, 4,4'-diaminodiphenyl sulfone, and 4,4'-diaminodiphenylmethane; And / or, the phenolic curing agent includes at least one of cardanol and phenolic resin.

5. The coating according to claim 1, characterized in that The raw material components of the coating further include, by weight: 0.1 to 100 parts of filler.

6. The coating according to claim 5, characterized in that The filler is selected from at least one of carbon black, graphite, carbon nanotubes, activated carbon, alumina, silica, mica, boron nitride, calcium silicate, titanium dioxide, MXene, glass microspheres, iron powder, iron salt, cobalt chloride, nickel chloride, sodium tripolyphosphate, mica iron oxide, aluminum phosphate, glass flakes, zinc phosphate, and calcium phosphate.

7. A method for preparing a coating according to any one of claims 1 to 6, characterized in that: The following steps are involved: The raw material components are mixed according to weight proportions, heated and cured, and crushed to obtain the coating.

8. Use of the coating prepared by the preparation method as claimed in claim 7 in coating of metal substrates.

9. An anti-corrosion coating, characterized in that: The raw materials for preparing the anti-corrosion coating include the coating prepared by the preparation method as described in claim 7.

10. A coated product, characterized in that: It comprises a metal substrate and a coating applied on the surface of the metal substrate; the coating is the anti-corrosion coating according to claim 9.

11. A household appliance, characterized in that: The raw materials for preparing the household electrical appliance include the coating according to any one of claims 1 to 6 or the anti-corrosion coating according to claim 9.

12. The household appliance according to claim 11, characterized in that: The household electrical appliances include cleaning appliances, kitchen appliances, electric heating appliances, audio-visual appliances, air conditioners or water heaters.

13. The household appliance according to claim 11, characterized in that: The household electrical appliances also include refrigeration appliances.

14. Use of the coating according to any one of claims 1 to 6 or the anti-corrosion coating according to claim 9 in a hot and humid environment or an acid-base environment.

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