Coating, preparation method and application thereof, and coated product

Abstract

The invention discloses a coating as well as a preparation method and application thereof and a coated product. According to the coating provided by the invention, the curing modification of the epoxy resin coating is realized by adjusting the components of the curing agent: a primary amine group contained in the curing agent reacts with an epoxy group to generate secondary amine and hydroxyl, and nitrogen atoms can improve the heat-resistant stability of a cross-linked network; a phenolic hydroxyl group reacts with an epoxy group to generate an ether bond and a hydroxyl group, and the ether bond can improve the overall flexibility of an epoxy resin coating; the anhydride group reacts with the epoxy group to generate various anhydride epoxy intermediates, so that the overall heat resistance of the epoxy resin is improved; the introduction of the ammonium salt can reduce the curing temperature of the epoxy resin, and the introduction of the metal ions can improve the anti-rust performance of the epoxy coating. Finally, the curing agent is used for curing the epoxy resin, so that the corrosion resistance, the adhesive property and the high-temperature resistance of the coating can be remarkably improved, and the application requirements in extremely severe environments such as high humidity and heat, acid-base corrosion and the like can be met.

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, the epoxy resin molten powder based on bisphenol A epoxy resin has problems such as 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 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 provides a coating and a preparation method and application thereof, and a coated product, which aims to solve the problem that the coating prepared by ordinary epoxy resin is difficult to meet the application requirements in extremely harsh environments such as high humidity and heat, acid and alkali corrosion, etc.

[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 240 parts of an epoxy resin composition, 1 to 100 parts of a curing agent composition;

[0007] The epoxy resin composition comprises 20 to 100 parts of bisphenol A epoxy resin, 10 to 40 parts of novolac epoxy resin, and 20 to 100 parts of hyperbranched epoxy resin;

[0008] The curing agent composition includes organic amine curing agents, phenol curing agents, strong organic acid curing agents, strong organic acid-ammonium salt curing agents, and metal salt curing agents.

[0009] 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 curing modification of epoxy resin coating by adjusting the formula of the curing agent component (including organic amine curing agent, phenol curing agent, strong organic acid curing agent, strong organic acid-ammonium salt curing agent, and metal salt curing agent): the organic amine curing agent contains NH bond, which can react with the epoxy group of epoxy resin, wherein the primary amine reacts with the epoxy group to produce secondary amine and hydroxyl group, and the nitrogen atom can improve the heat resistance stability of the cross-linked network; the phenol curing agent contains phenol group, and the phenolic hydroxyl group reacts with the epoxy group to produce ether bond and hydroxyl group, and the ether bond can improve the overall flexibility of the epoxy resin coating; the strong organic acid curing agent contains anhydride group, and the anhydride group reacts with the epoxy group to produce a variety of anhydride epoxy intermediates, thereby improving the overall heat resistance of the epoxy resin; the strong organic acid-ammonium salt curing agent and the metal salt curing agent are used as auxiliary curing agents, and the introduction of ammonium salt can reduce the curing temperature of the epoxy resin, and the introduction of metal ions can improve the rust resistance of the epoxy coating. Therefore, 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 through the combination of the above-mentioned curing agents. Moreover, in the coating component, the epoxy resin is obtained by a reasonable ratio of bisphenol A epoxy resin, phenolic epoxy resin, and hyperbranched epoxy resin, which can increase the crosslinking degree of the resin and thus improve the thermal stability of the resin. Finally, the present invention uses the above-mentioned curing agent combination to cure the epoxy resin, which can significantly improve the corrosion resistance, bonding performance, high temperature resistance and protection ability of the coating to the substrate, and can meet the application requirements in extremely harsh environments such as high humidity and heat, acid and alkali corrosion.

[0010] In some embodiments of the present invention, the raw material components of the coating include, by weight: 105 to 185 parts of an epoxy resin composition and 30 to 40 parts of a curing agent composition.

[0011] In some embodiments of the present invention, the epoxy resin composition comprises, by weight, 50 to 100 parts of bisphenol A epoxy resin, 15 to 35 parts of novolac epoxy resin and 40 to 50 parts of hyperbranched epoxy resin.

[0012] 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.

[0013] In some embodiments of the present invention, the phenolic curing agent is selected from at least one of cardanol and phenolic resin.

[0014] In some embodiments of the present invention, the strong organic acid curing agent is selected from at least one of maleic anhydride and phthalic anhydride.

[0015] In some embodiments of the present invention, the strong organic acid-ammonium salt curing agent is selected from boron trifluoride-ethylamine complex.

[0016] In some embodiments of the present invention, the metal salt curing agent is selected from at least one of triethyldiphenylammonium dithiophosphate zinc complex and triethyldiphenylammonium dithiophosphate cobalt complex.

[0017] In some embodiments of the present invention, the bisphenol A epoxy resin is selected from at least one of E51 epoxy resin, E44 epoxy resin, E20 epoxy resin and E12 epoxy resin.

[0018] In some embodiments of the present invention, the novolac epoxy resin is selected from at least one of F51 epoxy resin and NPCN-704 epoxy resin.

[0019] In some embodiments of the present invention, the hyperbranched epoxy resin is selected from at least one of AFG-90 epoxy resin, AFG-90H epoxy resin, AG-80 epoxy resin, AG-70 epoxy resin, AG-601 epoxy resin and AG-602 epoxy resin.

[0020] 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.

[0021] 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, cobalt chloride, nickel chloride, sodium tripolyphosphate, mica iron oxide, aluminum phosphate, glass flakes, zinc phosphate and calcium phosphate.

[0022] An embodiment of the second aspect of the present invention provides a method for preparing the coating as described above, comprising the steps of: mixing the raw materials according to weight components, heating and curing, and then crushing them using a grinder to obtain epoxy resin sintered powder.

[0023] The preparation method according to the embodiment of the second aspect of the present invention has at least the following beneficial effects: the preparation method of the coating provided by the present invention has a simple process, mild reaction conditions, easy operation, high production efficiency, and is suitable for large-scale production applications.

[0024] In some embodiments of the present invention, the heating and curing process is: heating to 30-100° C. and curing for 15-60 minutes.

[0025] In some embodiments of the present invention, the heating curing process is gradient temperature rise curing, which includes two stages: heating to 30-80°C for curing for 10-30 minutes, and then heating to 80-100°C for curing for 10-30 minutes.

[0026] An embodiment of the third aspect of the present invention provides the use of the coating as described above or the coating prepared by the preparation method as described above in coating of a metal substrate.

[0027] According to the application of the third aspect of the embodiment of the present invention, there are at least the following beneficial effects: the coating obtained by the present invention has the characteristics of high heat resistance, easy processing, and high adhesion. It is applied to the coating of metal substrates to form a coating with high density, strong anti-penetration and high heat resistance, which can meet the application requirements in extremely harsh environments such as high humidity and heat, acid and alkali corrosion.

[0028] In some embodiments of the present invention, the metal substrate includes a single metal or a metal alloy.

[0029] An embodiment of the fourth aspect of the present invention provides an anti-corrosion coating, wherein the coating as described in any one of the above items or the coating prepared by the preparation method as described in any one of the above items is uniformly coated on the surface of a metal substrate, and the anti-corrosion coating is obtained after curing.

[0030] The anti-corrosion coating according to the fourth aspect of the embodiment of the present invention has at least the following beneficial effects: the present invention applies the above-mentioned coating to a 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 such as high humidity and heat, acid and alkali corrosion, etc.

[0031] An embodiment of the fifth aspect of the present invention provides a coated product, comprising a metal substrate and the coating as described above or the coating prepared by the preparation method as described above, coated on the metal substrate.

[0032] In some embodiments of the present invention, the metal substrate includes a single metal or a metal alloy.

[0033] An embodiment of the sixth aspect of the present invention provides an application of a coating as described in any one of the above items or an anti-corrosion coating as described above in the field of home appliance manufacturing.

[0034] 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 particularly pointed out in the description, claims and drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0035] The present invention will be further described below with reference to the accompanying drawings and embodiments, wherein:

[0036] Figure 1 is the DSC spectrum of the epoxy resin powder before curing in Example 1 of the present invention;

[0037] Figure 2 is the DSC spectrum of the epoxy resin powder before curing in Example 2 of the present invention;

[0038] Figure 3 is a DSC spectrum of the epoxy resin cured product after curing in Example 1 of the present invention;

[0039] Figure 4 is a DSC spectrum of the epoxy resin cured product after curing in Example 2 of the present invention;

[0040] Figure 5 FTIR spectrum of epoxy resin powder before curing in Example 1 of the present invention;

[0041] Figure 6 FTIR spectrum of epoxy resin powder before curing in Example 2 of the present invention;

[0042] Figure 7 FTIR spectrum of the cured epoxy resin material in Example 1 of the present invention;

[0043] Figure 8 FTIR spectrum of the cured epoxy resin material after curing in Example 2 of the present invention;

[0044] Fig. 9 is the TGA curve of the cured epoxy resin coating in Example 1 of the present invention in air atmosphere;

[0045] Fig.10 This is the TGA curve of the cured epoxy resin coating in Example 1 of the present invention under an argon atmosphere. DETAILED DESCRIPTION

[0046] 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.

[0047] 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.

[0048] 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.

[0049] 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.

[0050] The first aspect of the present invention provides a coating, wherein the raw material components of the coating include, by weight: 50 to 240 parts of an epoxy resin composition and 1 to 100 parts of a curing agent composition; wherein the epoxy resin composition includes 20 to 100 parts of a bisphenol A epoxy resin, 10 to 40 parts of a phenolic epoxy resin, and 20 to 100 parts of a hyperbranched epoxy resin; and the curing agent composition includes an organic amine curing agent, a phenolic curing agent, a strong organic acid curing agent, a strong organic acid-ammonium salt curing agent, and a metal salt curing agent.

[0051] The coating provided by the present invention realizes curing modification of epoxy resin coating by adjusting the formula of curing agent components (including organic amine curing agent, phenol curing agent, strong organic acid curing agent, strong organic acid-ammonium salt curing agent, and metal salt curing agent): the organic amine curing agent contains NH bond, which can react with the epoxy group of epoxy resin, wherein the primary amine reacts with the epoxy group to produce secondary amine and hydroxyl group, and the nitrogen atom can improve the heat resistance stability of the cross-linked network; the phenol curing agent contains phenol group, the phenolic hydroxyl group reacts with the epoxy group to produce ether bond and hydroxyl group, and the ether bond can improve the overall flexibility of epoxy resin coating; the strong organic acid curing agent contains anhydride group, the anhydride group reacts with the epoxy group to produce a variety of anhydride epoxy intermediates, and improves the overall heat resistance of epoxy resin; the strong organic acid-ammonium salt curing agent and the metal salt curing agent are used as auxiliary curing agents, the introduction of ammonium salt can reduce the curing temperature of epoxy resin, and the introduction of metal ions can improve the anti-rust performance of epoxy coating. Therefore, the present invention can achieve the epoxy resin coating processing temperature reduction, enhanced heat resistance, enhanced permeability or enhanced rust resistance through the combination of the above-mentioned curing agent. In addition, in the coating component of the present invention, the epoxy resin is obtained by a reasonable ratio of bisphenol A epoxy resin, phenolic epoxy resin, and hyperbranched epoxy resin, which can increase the crosslinking degree of the resin and thus improve the thermal stability of the resin. Finally, the present invention uses the above-mentioned curing agent combination to cure the epoxy resin, which can significantly improve the corrosion resistance, bonding performance, high temperature resistance and protection ability of the substrate of the coating, and can meet the application requirements under extremely harsh environments such as high humidity and heat, acid and alkali corrosion.

[0052] In some embodiments of the present invention, the raw material components of the coating include, by weight: 105 to 185 parts of the epoxy resin composition and 30 to 40 parts of the curing agent composition.

[0053] In some embodiments of the present invention, the epoxy resin composition includes 50-100 parts of bisphenol A epoxy resin, 15-35 parts of novolac epoxy resin and 40-50 parts of hyperbranched epoxy resin by weight. In the coating component of the present invention, the epoxy resin is obtained by reasonable proportioning of bisphenol A epoxy resin, novolac epoxy resin and hyperbranched epoxy resin, which can increase the crosslinking degree of the resin and thus improve the thermal stability of the resin.

[0054] In some embodiments of the present invention, the organic amine curing agent is selected from at least one of 4,4'-(1,4-phenylenedioxy) diphenylamine, 4,4'-bis(4-aminophenoxy) diphenyl sulfone, 4,4'-bis(3-aminophenoxy) diphenyl sulfone, 4,4'-diaminodiphenyl sulfone and 4,4'-diaminodiphenylmethane. The organic amine curing agent 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 hydroxyls. The epoxy resin coating cured with the organic amine curing agent has high heat resistance, but is brittle.

[0055] In some embodiments of the present invention, the phenolic curing agent is selected from at least one of cardanol and phenolic resin. The phenolic curing agent contains a phenol group, and its phenolic hydroxyl group 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.

[0056] In some embodiments of the present invention, the strong organic acid curing agent is selected from at least one of maleic anhydride and phthalic anhydride. The strong organic acid curing agent contains anhydride groups, wherein the anhydride groups first react with hydroxyl groups in the epoxy resin to form a monoester, and the hydroxyl groups in the monoester participate in the curing reaction of the epoxy resin. The epoxy resin cured by the strong organic acid curing agent has a high processing temperature, and although the reaction is slow, it has good heat resistance.

[0057] In some embodiments of the present invention, the strong organic acid-ammonium salt curing agent is selected from boron trifluoride-ethylamine complex. The strong organic acid / ammonium salt curing agent is used as an auxiliary curing agent to reduce the curing temperature of the epoxy resin.

[0058] In some embodiments of the present invention, the metal salt curing agent is selected from at least one of triethyl diphenyl ammonium dithiophosphate zinc complex and triethyl diphenyl ammonium dithiophosphate cobalt complex. The metal salt curing agent is an organic curing agent modified by zinc or cobalt, which is used as an auxiliary curing agent to enhance the rust-proof performance of the epoxy coating.

[0059] In some embodiments of the present invention, the curing agent composition may further include a metal curing agent, such as boron trifluoride-ethylamine complex, SnCl4, AlCl3, etc.

[0060] In some embodiments of the present invention, the curing agent composition includes an organic amine curing agent, a phenol curing agent, a strong organic acid curing agent, a strong organic acid-ammonium salt curing agent and a metal salt curing agent.

[0061] The present invention utilizes a combination of curing agents (including organic amine curing agents, phenolic curing agents, strong organic acid curing agents, strong organic acid-ammonium salt curing agents, and metal salt curing agents) to achieve the effects of reduced processing temperature, enhanced heat resistance, enhanced permeability, and enhanced rust resistance of the cured epoxy resin coating: in the curing agent combination, the primary amine group reacts with the epoxy group to produce secondary amine and hydroxyl group, and the nitrogen atom can improve the heat resistance stability of the cross-linked network; the phenolic hydroxyl group reacts with the epoxy group to produce ether bonds and hydroxyl groups, and the ether bonds can improve the overall flexibility of the epoxy resin coating; the anhydride group reacts with the epoxy group to produce a variety of anhydride epoxy intermediates, thereby improving the overall heat resistance of the epoxy resin; the strong organic acid-ammonium salt curing agent and the metal salt curing agent are used as auxiliary curing agents, the introduction of ammonium salt can reduce the curing temperature of the epoxy resin, and the introduction of metal ions can improve the rust resistance of the epoxy coating, thereby finally achieving the effects of reduced processing temperature, enhanced heat resistance, enhanced permeability, and enhanced rust resistance of the epoxy resin coating. Therefore, the present invention utilizes a combination of organic amine curing agents, phenolic curing agents, strong organic acid curing agents, strong organic acid-ammonium salt curing agents, and metal salt curing agents to cure the epoxy resin, which can significantly improve the corrosion resistance 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, etc.

[0062] In some embodiments of the present invention, the bisphenol A epoxy resin is selected from at least one of E51 epoxy resin, E44 epoxy resin, E20 epoxy resin and E12 epoxy resin, but is not limited thereto, and may also be selected from common types in the art.

[0063] In some embodiments of the present invention, the phenolic epoxy resin is selected from at least one of F51 epoxy resin and NPCN-704 epoxy resin, but is not limited thereto, and may also be selected from common types in the art.

[0064] In some embodiments of the present invention, the hyperbranched epoxy resin is selected from at least one of AFG-90 epoxy resin, AFG-90H epoxy resin, AG-80 epoxy resin, AG-70 epoxy resin, AG-601 epoxy resin and AG-602 epoxy resin, but is not limited thereto and can also be selected from common models in the art.

[0065] In some embodiments of the present invention, the raw material components of the coating further include: 0.1 to 100 parts of filler, preferably 0.1 to 10 parts by weight.

[0066] In some embodiments of the present invention, the filler is selected from at least one of carbon black, graphite, carbon nanotubes, activated carbon, aluminum oxide, silicon dioxide, mica, boron nitride, calcium silicate, benzoin, titanium dioxide, MXene, glass microspheres, quartz sand, iron powder, iron salt, cobalt chloride, nickel chloride, sodium tripolyphosphate, mica iron oxide, aluminum phosphate, glass flakes, zinc phosphate and calcium phosphate, preferably benzoin (benzoyl ethyl ketone). The addition of fillers can be used to regulate the adhesion of the resin adhesive, and / or high temperature resistance, and / or give the material other known excellent properties, and / or control costs. For example, benzoin in the filler can be used as a defoaming agent, silicon dioxide or aluminum oxide 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. 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.

[0067] The second aspect of the present invention provides a method for preparing the above-mentioned coating, comprising the steps of: mixing the raw materials according to weight components in an inert atmosphere or an air atmosphere, heating and curing, and then crushing them using a grinder to obtain epoxy resin sintered powder.

[0068] The coating preparation method provided by the invention has simple process, mild reaction conditions, easy operation, high production efficiency and is suitable for large-scale production application.

[0069] In some embodiments of the present invention, the heating and curing process is: heating to 30-100° C. and curing for 15-60 minutes.

[0070] In some embodiments of the present invention, the heating curing process is gradient temperature rise curing, which includes two stages: heating to 30-80° C. for curing for 10-30 min, and then heating to 80-100° C. for curing for 10-30 min.

[0071] In some preferred embodiments of the present invention, the heating curing process is gradient temperature rise curing, which includes two stages: heating to 30-80° C. for curing for 10 min, and then heating to 80-100° C. for curing for 10 min.

[0072] In some embodiments of the present invention, the prepolymerized resin after heating and curing is crushed by an ACM grinder to obtain epoxy resin sintered powder.

[0073] 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 substrate; it can also be prepared into a slurry and then used to coat the substrate.

[0074] 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.

[0075] 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 such as high humidity and heat, acid and alkali corrosion, etc.

[0076] In some embodiments of the present invention, the metal substrate includes a single metal or a metal alloy, such as tinplate, titanium alloy, stainless steel, and the like.

[0077] A fourth aspect of the present invention provides an anti-corrosion coating, which is obtained by uniformly coating the above-mentioned coating or the coating prepared by the above-mentioned preparation method on the surface of a metal substrate and curing the coating.

[0078] 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, and the formed coating has high density, strong anti-permeability, and high heat resistance, and can meet the application requirements in extremely harsh environments such as high humidity and heat, acid and alkali corrosion, etc.

[0079] In some embodiments of the present invention, the coating powder can be electrostatically sprayed onto the surface of the metal substrate; the coating can also 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 a conventional method in the art, which is not limited here. The curing method can be a conventional method in the art, such as heating curing, which is not limited here.

[0080] In some embodiments of the present invention, the thickness of the anti-corrosion coating is 100-500 μm, preferably 200-500 μm, and more preferably about 250 μm.

[0081] A fifth aspect of the present invention provides a coated product, comprising a metal substrate and the above-mentioned coating or the coating prepared by the above-mentioned preparation method coated on the metal substrate.

[0082] In some embodiments of the present invention, the metal substrate includes a single metal or a metal alloy, such as tinplate, titanium alloy, stainless steel, and the like.

[0083] A sixth aspect of the present invention provides the use of the above-mentioned paint or the above-mentioned anti-corrosion coating in the field of home appliance manufacturing.

[0084] In some embodiments of the present invention, 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 stereos, etc.).

[0085] 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 particularly pointed out in the description, claims and drawings.

[0086] Example 1

[0087] By weight, 65 parts of E51 epoxy resin, 30 parts of F51 epoxy resin, 45 parts of AFG-90 epoxy resin, 35 parts of curing agent composition (including 10 parts of 4,4'-(1,4-phenylenedioxy) dianiline, 5 parts of cardanol, 5 parts of maleic anhydride, 8 parts of boron trifluoride-ethylamine complex, 7 parts of triethyl diphenyl ammonium zinc dithiophosphate complex), and 1 part of benzoin were mixed, and then cured at 30-80°C for 10 minutes and 80-100°C for 10 minutes under an inert atmosphere. Then, the cured prepolymer resin was crushed by an ACM grinder to obtain a coating powder; after pouring the coating powder into an electrostatic spray fluidized barrel, it was sprayed with tinplate as a metal substrate, and then thermally cured for 15 minutes in an air environment at 230°C to form a final coating.

[0088] The thickness of the coating is 250 μm.

[0089] Example 2

[0090] The difference from Example 1 is that the formula of the coating is different. In this embodiment, by weight, 50 parts of E20 epoxy resin, 15 parts of NPCN-704 epoxy resin, 40 parts of AG-601 epoxy resin, 30 parts of curing agent composition (including 7 parts of 4,4'-bis(4-aminophenoxy)diphenyl sulfone, 8 parts of cardanol, 5 parts of phthalic anhydride, 5 parts of boron trifluoride-ethylamine complex, 5 parts of triethyldiphenyl ammonium cobalt dithiophosphate complex), and 0.1 parts of benzoin. The rest are the same as in Example 1.

[0091] Example 3

[0092] The difference from Example 1 is that the formula of the coating is different. In this example, by weight, 95 parts of E44 epoxy resin, 35 parts of F51 epoxy resin, 50 parts of AG-80 epoxy resin, 40 parts of curing agent composition (including 10 parts of 4,4'-diaminodiphenylmethane, 5 parts of phenolic resin, 3 parts of maleic anhydride, 12 parts of boron trifluoride-ethylamine complex, 10 parts of triethyldiphenyl ammonium dithiophosphate cobalt complex), and 10 parts of benzoin. The rest is the same as Example 1.

[0093] Comparative Example 1

[0094] The difference from Example 1 is that the formula of the coating is different. In this embodiment, by weight, 30 parts of F51 epoxy resin, 45 parts of AFG-90 epoxy resin, 35 parts of curing agent composition (including 10 parts of 4,4'-(1,4-phenylenedioxy) dianiline, 5 parts of cardanol, 5 parts of maleic anhydride, 8 parts of boron trifluoride-ethylamine complex, 7 parts of triethyldiphenyl ammonium zinc dithiophosphate complex), 1 part of benzoin, and no bisphenol A epoxy resin is contained. Others are the same as Example 1.

[0095] Comparative Example 2

[0096] The difference from Example 1 is that the formula of the coating is different. In this embodiment, by weight, 65 parts of E51 epoxy resin, 45 parts of AFG-90 epoxy resin, 35 parts of curing agent composition (including 10 parts of 4,4'-(1,4-phenylenedioxy) dianiline, 5 parts of cardanol, 5 parts of maleic anhydride, 8 parts of boron trifluoride-ethylamine complex, 7 parts of triethyl diphenyl ammonium zinc dithiophosphate complex), 1 part of benzoin, and no phenolic epoxy resin is contained. Others are the same as Example 1.

[0097] Comparative Example 3

[0098] The difference from Example 1 is that the formula of the coating is different. In this embodiment, by weight, 65 parts of E51 epoxy resin, 30 parts of F51 epoxy resin, 35 parts of curing agent composition (including 10 parts of 4,4'-(1,4-phenylenedioxy) dianiline, 5 parts of cardanol, 5 parts of maleic anhydride, 8 parts of boron trifluoride-ethylamine complex, 7 parts of triethyldiphenyl ammonium zinc dithiophosphate complex), 1 part of benzoin, and no hyperbranched epoxy resin is contained. Others are the same as Example 1.

[0099] Comparative Example 4

[0100] The difference from Example 1 is that the coating formula is different. In this example, by weight, 65 parts of E51 epoxy resin, 30 parts of F51 epoxy resin, 45 parts of AFG-90 epoxy resin, 35 parts of boron trifluoride-ethylamine complex, and 1 part of benzoin are used. The rest is the same as Example 1.

[0101] Comparative Example 5

[0102] The difference from Example 1 is that the formula of the coating is different. In this embodiment, by weight, 65 parts of E51 epoxy resin, 30 parts of F51 epoxy resin, 45 parts of AFG-90 epoxy resin, 120 parts of curing agent composition (including 60 parts of 4,4'-(1,4-phenylenedioxy) dianiline and 60 parts of cardanol), and 1 part of benzoin are used. The rest are the same as in Example 1.

[0103] Comparative Example 6

[0104] The difference from Example 1 is that the curing method of the coating is different. In this example, the temperature is gradually increased from 120 to 150° C. under an inert atmosphere for 20 minutes. The other aspects are the same as in Example 1.

[0105] Comparative Example 7

[0106] The difference from Example 1 is that tinplate is used as the test sample and the surface is not covered with a protective coating.

[0107] Comparative Example 8

[0108] The difference from Example 1 is that tinplate is used as the test sample, the surface of which is sprayed with Degao electrostatic powder coating, and after spraying, it is cured at 230° C. for 1 hour, and the thickness of the cured coating is 250 μm.

[0109] Test Case

[0110] The epoxy resin coating in Example 1 was subjected to DSC testing. The temperature was raised from 0°C to 300°C at a heating rate of 10K / min. The DSC spectra of the epoxy resin coating before and after curing were as follows: Figure 1 , 3 As shown. In the figure, the heat release is above the ordinate, and it is found that it melts above 50°C, the solidification peak is at 160°C, the glass transition temperature after solidification is at 151°C, and the initial decomposition temperature is above 323°C.

[0111] The epoxy resin coating in Example 2 was subjected to DSC testing. The temperature was raised from 0°C to 300°C at a heating rate of 10K / min. The DSC spectra of the epoxy resin coating before and after curing were as follows: Figure 2 , 4 It was found to melt above 50°C and solidify at a peak of 165°C.

[0112] In Examples 1 and 2, the FTIR spectra of the epoxy resin coating before and after curing are as follows: Figure 5-8 As shown. Figure 5-6 It can be seen that before the epoxy resin coating is cured, 913cm -1 There is an epoxy group peak at Figure 7-8 It can be seen that after the epoxy resin is cured, 913cm -1The epoxy group peak disappears at 3400cm -1 The hydroxyl group peak at 400 nm was significantly enhanced, proving that the curing agent composition successfully cured the epoxy resin.

[0113] The TGA curves of the coating in Example 1 after curing in air atmosphere and argon atmosphere are as follows: Figure 9-10 As shown by Fig. 9 It can be seen that the resin has three decomposition temperatures in the air. The lower temperature is the oxidative decomposition of the hydroxyl group in the epoxy resin, followed by the oxidative decomposition of the secondary amine group in the epoxy resin, and finally the oxidative decomposition of the organic skeleton of the epoxy resin. Fig.10 It can be seen that epoxy resin has two decomposition temperatures in an argon environment. The lower temperature is the decomposition of the hydroxyl groups in the epoxy resin, and the last is the carbonization of the epoxy resin skeleton.

[0114] The pull-out strength of the coatings in Examples 1-2 of the present invention based on the tinplate substrate was tested, and the testing standard was ISO4624: 2023. The pull-out strength of the coating in Example 1 based on the tinplate substrate was 1.168 Mpa, and the pull-out strength of the coating in Example 2 based on the tinplate substrate was 1.143 Mpa, which proved that the coating formed by the coating had the characteristics of high density and strong adhesion.

[0115] The cross-scratch test was performed on Examples 1-3 and Comparative Examples 1-8 to evaluate the corrosion resistance of the coating. The method is: 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 results are shown in Table 1:

[0116] Table 1

[0117] 7-day salt spray test after coating is scratched Example 1 No obvious changes on the surface Example 2 No obvious changes on the surface Example 3 No obvious changes on the surface Comparative Example 1 Partial peeling of the surface coating Comparative Example 2 Partial peeling of the surface coating Comparative Example 3 Partial peeling of surface coating Comparative Example 4 Surface coating peeling off seriously Comparative Example 5 Severe corrosion of surface coating Comparative Example 6 Severe shrinkage of surface coating Comparative Example 7 The coating peels off seriously at the cross section Comparative Example 8 The coating peels off seriously at the cross section

[0118] The corrosion resistance of the anti-corrosion coating was evaluated through a scratch test, and it was found that there was no obvious change in the surface coating of Examples 1-3 before and after the experiment. Except for the corrosion of the exposed external substrate, there was no corrosion in other places. The surface coating of Comparative Examples 1-3 partially fell off, indicating that the epoxy resin requires a reasonable ratio of bisphenol A epoxy resin, phenolic epoxy resin, and hyperbranched epoxy resin; Comparative Examples 4-5 fell off seriously, indicating that the curing agent composition of the present invention was not used or the number of parts was unreasonable, then the corrosion resistance of the coating could not be improved; Comparative Example 6 had serious shrinkage holes on the surface coating, indicating that the gradient heating method of the present invention needs to be precisely controlled, otherwise a uniform coating could not be formed; Comparative Example 7 had serious corrosion at the scratch point and the corrosion tended to extend outward, and Comparative Example 8 had serious coating shedding at the scratch point, and serious corrosion at the scratch point and the corrosion tended to extend outward.

[0119] The high temperature resistance and long-term corrosion resistance of Examples 1-3 and Comparative Examples 1-8 were accelerated by taking the coating samples, soaking them in 170°C hot water at 0.65MPa in a high temperature autoclave for 2 days, observing the surface of the samples and detecting their electrochemical impedance (test standard GB / T 39482-2020). The results are shown in Table 2:

[0120] Table 2

[0121]

[0122] For the coatings prepared in the examples and comparative examples, the initial electrochemical impedance was 10 ^ 12Ω, after being immersed in 170℃ hot water 0.65MPa in a high temperature autoclave for 2 days, the surface coating of Examples 1-3 had no obvious change, and the electrochemical impedance only dropped to 10 ^ 10Ω, while the surface coating of Comparative Examples 1-3 had point-like bubbles, and the electrochemical impedance dropped to 10 ^ 6Ω; Comparative Example 4-5 has serious blistering on the surface coating, and the electrochemical impedance drops to 10 ^ 6Ω; Comparative Example 6 has severe blistering on the surface coating, and the electrochemical impedance drops to 10 ^ 7Ω; the surface corrosion of comparative example 7 is serious, and the surface coating of comparative example 8 has fallen off and has no anti-corrosion effect.

[0123] The above is a specific description of the preferred implementation of the present application, but the present application is not limited to the above-mentioned implementation mode. Technical personnel familiar with the field can also make various equivalent deformations or substitutions without violating the spirit of the present application. These equivalent deformations or substitutions are all included in the scope defined by the claims of the present application.

Claims

1. A coating, characterized in that: The raw material components of the coating include, by weight: 50 to 240 parts of an epoxy resin composition and 1 to 100 parts of a curing agent composition; The epoxy resin composition comprises 20 to 100 parts of bisphenol A epoxy resin, 10 to 40 parts of novolac epoxy resin, and 20 to 100 parts of hyperbranched epoxy resin; The curing agent composition includes organic amine curing agents, phenol curing agents, strong organic acid curing agents, strong organic acid-ammonium salt curing agents, and metal salt curing agents.

2. The coating according to claim 1, characterized in that The raw material components of the coating include, by weight: 105 to 185 parts of an epoxy resin composition and 30 to 40 parts of a curing agent composition.

3. The coating according to claim 2, characterized in that The epoxy resin composition comprises 50 to 100 parts of bisphenol A epoxy resin, 15 to 35 parts of novolac epoxy resin and 40 to 50 parts of hyperbranched epoxy resin in parts by weight.

4. The coating according to claim 1 or 2, characterized in that: 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; And / or, the phenolic curing agent is selected from at least one of cardanol and phenolic resin; And / or, the strong organic acid curing agent is selected from at least one of maleic anhydride and phthalic anhydride; and / or, the strong organic acid-ammonium salt curing agent is selected from boron trifluoride-ethylamine complex; And / or, the metal salt curing agent is selected from at least one of triethyldiphenylammonium dithiophosphate zinc complex and triethyldiphenylammonium dithiophosphate cobalt complex.

5. The coating according to claim 1, 2 or 3, characterized in that: The bisphenol A epoxy resin is selected from at least one of E51 epoxy resin, E44 epoxy resin, E20 epoxy resin and E12 epoxy resin.

6. The coating according to claim 1, 2 or 3, characterized in that: The phenolic epoxy resin is selected from at least one of F51 epoxy resin and NPCN-704 epoxy resin.

7. The coating according to claim 1, 2 or 3, characterized in that: The hyperbranched epoxy resin is selected from at least one of AFG-90 epoxy resin, AFG-90H epoxy resin, AG-80 epoxy resin, AG-70 epoxy resin, AG-601 epoxy resin and AG-602 epoxy resin.

8. The coating according to claim 1, 2 or 3, characterized in that: The raw material components of the coating further include: 0.1 to 100 parts of filler by weight.

9. The coating according to claim 8, 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, benzoin, titanium dioxide, MXene, glass microspheres, quartz sand, iron powder, iron salt, cobalt chloride, nickel chloride, sodium tripolyphosphate, mica iron oxide, aluminum phosphate, glass flakes, zinc phosphate and calcium phosphate.

10. A method for preparing a coating according to any one of claims 1 to 9, characterized in that: The method comprises the following steps: mixing raw materials according to weight components, heating and solidifying the mixture, and then crushing the mixture by a grinding machine to obtain epoxy resin sintered powder.

11. The method for preparing the coating according to claim 10, characterized in that: The heating and curing process is: heating to 30-100° C. and curing for 15-60 minutes.

12. The method for preparing the coating according to claim 11, characterized in that: The heating curing process is a gradient temperature rise curing process, which includes two stages: heating to 30-80° C. for curing for 10-30 min, and then heating to 80-100° C. for curing for 10-30 min.

13. Use of the coating according to any one of claims 1 to 9 or the coating prepared by the preparation method according to any one of claims 10 to 12 in coating a metal substrate.

14. An anti-corrosion coating, characterized in that: The coating according to any one of claims 1 to 9 or the coating prepared by the preparation method according to any one of claims 10 to 12 is uniformly coated on the surface of the metal substrate, and the anti-corrosion coating is obtained after curing.

15. A coated product, characterized in that The invention comprises a metal substrate and a coating as claimed in any one of claims 1 to 9 or a coating prepared by the preparation method as claimed in any one of claims 10 to 12, which is coated on the metal substrate.

16. The coated product according to claim 15, characterized in that The metal substrate includes a single metal or a metal alloy.

17. Use of the coating according to any one of claims 1 to 9 or the anti-corrosion coating according to claim 14 in the field of home appliance manufacturing.

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