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. The phenolic resin composition is condensed under an acidic condition to cure epoxy resin, so that an epoxy group can be subjected to a ring-opening reaction, phenolic aldehyde side groups with high crosslinking density and a large number of aromatic rigid heterocyclic rings are introduced to a long chain of the epoxy resin, and the thermal stability of the resin in a high-temperature environment is greatly improved; all benzene rings on a long chain form an integral conjugated structure, so that the thermal stability and chemical stability of the resin are further improved. The epoxy resin is obtained by reasonably proportioning bisphenol A epoxy resin, novolac epoxy resin and hyperbranched epoxy resin, and the crosslinking degree of the resin can be increased, so that the thermal stability of the resin is improved. Finally, the phenolic resin composition subjected to polycondensation under the acidic condition is used for curing the epoxy resin, so that the high-temperature stability, the chemical stability and the wear resistance of the coating can be remarkably improved, and the coating has good adhesive force and can meet the application requirements of complex and harsh extreme environments such as high temperature, high humidity, chemical corrosion and the like.

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.

[0003] In the related art, epoxy resin coating is a liquid or solid coating composed of epoxy resin, curing agent, toughening agent, accelerator, diluent, filler, stabilizer, coupling agent and other additives. Among them, epoxy resin and curing agent are indispensable components. Epoxy resin coating also stands out among many coatings with its good comprehensive performance and wide applicability. However, epoxy resin coating cured by traditional curing agent has a single heat-resistant rigid group in the cross-linked network structure, and its thermal stability, chemical stability, wear resistance and other properties are increasingly difficult to meet its use requirements in complex and harsh extreme environments such as high temperature, high humidity, corrosion and wear.

[0004] Therefore, it is an urgent problem to provide a coating material that can be used in complex, harsh and extreme environments such as high temperature and humidity, corrosion and wear, and chemical corrosion, and has good high temperature stability, good chemical stability and good 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 a preparation method and application thereof, and a coated product, aiming to solve the problem that the epoxy resin coating cured by the conventional curing agent is difficult to meet the application requirements of complex and harsh extreme environments such as humidity, heat, and chemical 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: 70 to 240 parts of an epoxy resin composition and 10 to 100 parts of a phenolic resin 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 40 to 100 parts of hyperbranched epoxy resin;

[0008] The phenolic resin composition is selected from phenolic resin polycondensed under acidic conditions.

[0009] According to the coating of the embodiment of the first aspect of the present invention, at least the following beneficial effects are achieved: the coating provided by the present invention, using the phenolic resin composition polycondensed under acidic conditions to cure the epoxy resin, can significantly improve the high temperature stability, chemical stability, wear resistance and good adhesion of the coating. During the polycondensation process of the phenolic resin polycondensed under acidic conditions, a large number of methylene cross-linking bridges are formed between phenol and aldehyde, so that the phenolic resin has a higher cross-linking density, giving it excellent high temperature stability and chemical stability, and the phenolic resin contains a large number of aromatic heterocycles, and the heterocycles form a mutually conjugated structure, which further enhances the heat resistance and chemical corrosion resistance of the phenolic resin. Using the above-mentioned phenolic resin composition to cure the epoxy resin can cause the epoxy group to undergo a ring-opening reaction, introduce a phenolic side group with a large cross-linking density and a large number of aromatic rigid heterocycles on the long chain of the epoxy resin, and greatly improve the thermal stability of the resin under high temperature environment; on the other hand, each benzene ring on the long chain forms an overall conjugated structure, further improving the thermal stability and chemical stability of the resin. In addition, in the coating components of the present invention, epoxy resin is obtained by reasonable proportioning from bisphenol A epoxy resin, phenolic epoxy resin, and hyperbranched epoxy resin, and the crosslinking degree of resin can be increased to improve the thermal stability of resin. Moreover, in the coating components, epoxy resin is obtained by reasonable proportioning from bisphenol A epoxy resin, phenolic epoxy resin, and hyperbranched epoxy resin, and the crosslinking degree of resin can be increased to improve the thermal stability of resin. Finally, the present invention proposes a phenolic resin-cured epoxy resin coating with excellent high temperature stability, chemical stability, wear resistance and good adhesion, and epoxy resin is cured using a phenolic resin composition, which can significantly improve the high temperature stability and chemical stability of the coating, and the coating formed by the above coating has the characteristics of high density, good adhesion, and resistance to high temperature and wet heat corrosion, which can meet the complex and harsh extreme environment application requirements such as high temperature and humidity, and chemical corrosion.

[0010] In some embodiments of the present invention, the raw material components of the coating include, by weight: 105 to 170 parts of epoxy resin composition and 30 to 50 parts of phenolic resin composition.

[0011] In some embodiments of the present invention, the phenolic resin composition is selected from at least one of 2123 phenolic resin, 2130 phenolic resin, 2402 phenolic resin and 6216 phenolic resin.

[0012] In some embodiments of the present invention, the epoxy resin composition comprises, by weight, 50 to 85 parts of bisphenol A epoxy resin, 15 to 35 parts of novolac epoxy resin and 40 to 50 parts of hyperbranched epoxy resin.

[0013] 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.

[0014] 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.

[0015] 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.

[0016] 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.

[0017] In some embodiments of the present invention, the filler is selected from at least one of silicon phosphate, silicone rubber, carbon black, iron powder, activated carbon, quartz sand, silica, mica, polysulfide rubber, boron nitride, calcium carbonate, calcium silicate, benzoin, MXene, silsesquioxane, glass microspheres, titanium dioxide, graphite, carbon nanotubes, ferrous chloride, ferric chloride, sodium chloride, cobalt chloride, iron oxide, ferrous oxide, cobalt oxide, aluminum oxide, nickel oxide, sodium tripolyphosphate, mica iron oxide, aluminum phosphate, glass flakes, zinc phosphate and calcium phosphate.

[0018] The 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 grinding and screening to obtain epoxy resin sintered powder.

[0019] 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.

[0020] In some embodiments of the present invention, the heating and curing process is: heating to 80-280° C. and curing for 15-60 minutes.

[0021] In some embodiments of the present invention, the heating curing process is gradient temperature rise curing, which includes two stages: heating to 100-230° C. for curing for 15-30 min, and then heating to 230-280° C. for curing for 15-30 min.

[0022] 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.

[0023] According to the application of the embodiment of the third aspect of the present invention, there are at least the following beneficial effects: the present invention applies the obtained coating to the coating of the metal substrate, and the formed coating has the characteristics of high density, good adhesion, and resistance to high temperature and wet heat corrosion, and can meet the application requirements of complex and harsh extreme environments such as high temperature, high humidity, and chemical corrosion.

[0024] In some embodiments of the present invention, the metal substrate includes a single metal or a metal alloy.

[0025] An embodiment of the fourth aspect of the present invention provides an anti-corrosion coating, wherein the coating as described above or the coating prepared by the preparation method as described above is uniformly coated on the surface of a metal substrate, and the anti-corrosion coating is obtained after curing.

[0026] 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 the characteristics of high density, good adhesion, and resistance to high temperature and wet heat corrosion, and can meet the application requirements of complex and harsh extreme environments such as high temperature, high humidity, and chemical corrosion.

[0027] 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.

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

[0029] An embodiment of the sixth aspect of the present invention provides the application of the coating as described above or the anti-corrosion coating as described above in the fields of home appliance manufacturing, aerospace, and microelectronic materials.

[0030] 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

[0031] The present invention will be further described below with reference to the accompanying drawings and embodiments, wherein:

[0032] Figure 1 is a DSC spectrum of the epoxy resin prepolymer before curing in Example 1 of the present invention;

[0033] Figure 2 The DSC spectrum of the epoxy resin coating cured by the phenolic resin in Example 1 of the present invention;

[0034] Figure 3FTIR spectrum of the epoxy resin prepolymer before curing in Example 1 of the present invention;

[0035] Figure 4 FTIR spectrum of the epoxy resin coating cured by phenolic resin in Example 1 of the present invention;

[0036] Figure 5 is the TGA curve of the epoxy resin coating cured by the phenolic resin in Example 1 of the present invention in air atmosphere;

[0037] Figure 6 This is the TGA curve of the epoxy resin coating cured by the phenolic resin in Example 1 of the present invention under an argon atmosphere. DETAILED DESCRIPTION

[0038] 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.

[0039] 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.

[0040] 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.

[0041] 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.

[0042] The first aspect of the present invention provides a coating, wherein the raw material components of the coating include, by weight: 70 to 240 parts of an epoxy resin composition and 10 to 100 parts of a phenolic resin 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 40 to 100 parts of a hyperbranched epoxy resin; and the phenolic resin composition is selected from a phenolic resin polycondensed under acidic conditions.

[0043] The coating provided by the present invention uses a phenolic resin composition polycondensed under acidic conditions to cure epoxy resin, which can significantly improve the high temperature stability, chemical stability, wear resistance and good adhesion of the coating. In the polycondensation process of the phenolic resin under acidic conditions, a large number of methylene cross-linking bridges are formed between phenol and aldehyde, so that the phenolic resin has a higher cross-linking density, giving it excellent high temperature stability and chemical stability, and the phenolic resin contains a large number of aromatic heterocycles, and the heterocycles form a mutually conjugated structure, which further enhances the heat resistance and chemical corrosion resistance of the phenolic resin. Using the above-mentioned phenolic resin composition to cure the epoxy resin, the epoxy group can undergo a ring-opening reaction, and a phenolic side group with a large cross-linking density and a large number of aromatic rigid heterocycles are introduced into the long chain of the epoxy resin, which greatly improves the thermal stability of the resin under high temperature environment; on the other hand, each benzene ring on the long chain forms an overall conjugated structure, which further improves the thermal stability and chemical stability of the resin. 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 cross-linking degree of the resin and thus improve the thermal stability of the resin. Finally, the present invention proposes a phenolic resin-cured epoxy resin coating with excellent high-temperature stability, chemical stability, wear resistance and good adhesion. The high-temperature stability and chemical stability of the coating can be significantly improved by curing the epoxy resin with a phenolic resin composition. The coating formed by the above coating has good heat resistance and strong adhesion, and can meet the application requirements of complex, harsh and extreme environments such as high temperature, high humidity and chemical corrosion resistance.

[0044] In some embodiments of the present invention, the raw material components of the coating include, by weight: 105-170 parts of epoxy resin composition and 30-50 parts of phenolic resin composition. The present invention uses the phenolic resin composition polycondensed under acidic conditions to cure the epoxy resin, which can significantly improve the high temperature stability, chemical stability and adhesion of the coating.

[0045] In some embodiments of the present invention, the epoxy resin composition includes 50-85 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.

[0046] In some embodiments of the present invention, the phenolic resin composition is selected from at least one of 2123 phenolic resin, 2130 phenolic resin, 2402 phenolic resin and 6216 phenolic resin.

[0047] The phenolic resin composition of the present invention is a polycondensed phenolic resin under acidic conditions. During the polycondensation process, a large number of methylene cross-linking bridges are formed between phenol and aldehyde, so that the phenolic resin has a higher cross-linking density, giving it excellent high-temperature stability and chemical stability. The phenolic resin contains a large number of aromatic heterocycles, and the heterocycles form a mutually conjugated structure, which further enhances the heat resistance and chemical corrosion resistance of the phenolic resin. The above-mentioned phenolic resin composition is used to cure epoxy resin, which can cause the epoxy group to undergo a ring-opening reaction, introduce a phenolic side group with a large cross-linking density and a large number of aromatic rigid heterocycles on the long chain of the epoxy resin, and greatly improve the thermal stability of the resin under high temperature environment; on the other hand, each benzene ring on the long chain forms an overall conjugated structure, which further improves the thermal stability and chemical stability of the resin.

[0048] 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.

[0049] 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.

[0050] 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.

[0051] 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.

[0052] In some embodiments of the present invention, the filler is selected from at least one of silicon phosphate, silicone rubber, carbon black, iron powder, activated carbon, quartz sand, silicon dioxide, mica, polysulfide rubber, boron nitride, calcium carbonate, calcium silicate, benzoin, MXene, silsesquioxane, glass microspheres, titanium dioxide, graphite, carbon nanotubes, ferrous chloride, ferric chloride, sodium chloride, cobalt chloride, ferric oxide, ferrous oxide, cobalt oxide, aluminum oxide, nickel oxide, sodium tripolyphosphate, mica iron oxide, aluminum phosphate, glass flakes, zinc phosphate and calcium phosphate, preferably benzoin (benzoyl alcohol ketone). The addition of fillers can be used to regulate the bonding force 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.

[0053] 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, heating and curing, and grinding and screening to obtain epoxy resin sintered powder.

[0054] The coating preparation method provided by the invention has simple processing technology, mild reaction conditions, easy operation, high production efficiency and is suitable for large-scale production application.

[0055] In some embodiments of the present invention, the heating and curing process is: heating to 80-280° C. and curing for 15-60 minutes.

[0056] In some embodiments of the present invention, the heating curing process is gradient temperature curing, which includes two stages: heating to 100-230° C. for curing for 15-30 min, and then heating to 230-280° C. for curing for 15-30 min.

[0057] In some preferred embodiments of the present invention, the heating curing process is gradient temperature rise curing, which includes two stages: heating to 100-230° C. for curing for 15 min, and then heating to 230-280° C. for curing for 15 min.

[0058] 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.

[0059] 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.

[0060] The present invention applies the coating obtained as described above to metal substrate coating, and the formed coating has the characteristics of high density, good adhesion, and resistance to high temperature and hot and humid corrosion, and can meet the application requirements of complex and harsh extreme environments such as high temperature, high humidity, and chemical corrosion.

[0061] 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.

[0062] 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.

[0063] The anticorrosion 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 the characteristics of high density, good adhesion, and resistance to high temperature and hot and wet corrosion, and can meet the application requirements of complex and harsh extreme environments such as high temperature, high humidity, and chemical corrosion.

[0064] 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.

[0065] 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.

[0066] 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.

[0067] 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.

[0068] A sixth aspect of the present invention provides the application of the above-mentioned coating or the above-mentioned anti-corrosion coating in the fields of home appliance manufacturing, aerospace, and microelectronic materials.

[0069] 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.).

[0070] 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.

[0071] Example 1

[0072] In parts by weight, 65 parts of E51 epoxy resin, 30 parts of F51 epoxy resin, 45 parts of AFG-90 epoxy resin, 40 parts of 2123 phenolic resin and 1 part of benzoin are mixed, and then cured at 100-230°C for 15 minutes and at 230-280°C for 15 minutes under an inert atmosphere, and then ground and sieved to obtain a coating powder; after pouring the coating powder into an electrostatic spray fluidized barrel, spraying it with tinplate as a metal substrate, and then heat curing it in an air environment at 230°C for 15 minutes to form a final coating.

[0073] The thickness of the coating is 250 μm.

[0074] Example 2

[0075] The difference from Example 1 is that the coating formula is different. In this example, 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 2130 phenolic resin, and 0.1 parts of benzoin are used. Other parts are the same as in Example 1.

[0076] Example 3

[0077] The difference from Example 1 is that the coating formula is different. In this example, by weight, 85 parts of E44 epoxy resin, 35 parts of F51 epoxy resin, 50 parts of AG-80 epoxy resin, 50 parts of 6216 phenolic resin, and 10 parts of benzoin are used. Other parts are the same as in Example 1.

[0078] Comparative Example 1

[0079] The difference from Example 1 is that the coating formula is different. In this example, by weight, 30 parts of F51 epoxy resin, 45 parts of AFG-90 epoxy resin, 40 parts of 2123 phenolic resin, and 1 part of benzoin are included, and bisphenol A epoxy resin is not included. Other parts are the same as Example 1.

[0080] Comparative Example 2

[0081] The difference from Example 1 is that the coating formula is different. In this example, by weight, 65 parts of E51 epoxy resin, 45 parts of AFG-90 epoxy resin, 40 parts of 2123 phenolic resin, and 1 part of benzoin are included, and no phenolic epoxy resin is included. Other parts are the same as Example 1.

[0082] Comparative Example 3

[0083] 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, 40 parts of 2123 phenolic resin, and 1 part of benzoin are used, and no hyperbranched epoxy resin is contained. Other parts are the same as Example 1.

[0084] Comparative Example 4

[0085] 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, 40 parts of boron trifluoride-ethylamine complex, and 1 part of benzoin are used, and no phenolic resin is contained. Other parts are the same as Example 1.

[0086] Comparative Example 5

[0087] The difference from Example 1 is that the curing method is different. In this example, the temperature is gradually increased from 60 to 80° C. for 30 minutes. The other aspects are the same as in Example 1.

[0088] Comparative Example 6

[0089] The difference from Example 1 is the curing method. In this example, the temperature is gradually increased from 300 to 350° C. for 30 minutes. The other aspects are the same as Example 1.

[0090] Comparative Example 7

[0091] The difference from Example 1 is that tinplate is used as the test sample and the surface is not covered with a protective coating.

[0092] Comparative Example 8

[0093] The difference from Example 1 is that tinplate is used as the test sample, 2123 phenolic resin is sprayed on the surface, and after spraying, it is cured at 200° C. for 1 hour, and the thickness of the cured coating is 250 μm.

[0094] Test Case

[0095] The DSC test was performed on the epoxy resin coating cured with phenolic resin in Example 1, starting from 0°C and heating up to 300°C at a rate of 10K / min. In this Example 1, the DSC spectra of the epoxy resin coating cured with phenolic resin before and after curing are as follows: Figure 1-2 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 150°C, the glass transition temperature is above 200°C, and the initial decomposition temperature is above 335°C.

[0096] In this Example 1, the FTIR spectra of the epoxy resin coating cured with phenolic resin before and after curing are as follows: Figure 3-4 As shown. Figure 3-4 It can be seen that the infrared peak of the epoxy group of the epoxy resin coating cured by phenolic resin decreases and the infrared peak of the ether bond increases before and after curing, which proves that phenolic resin can effectively cure epoxy resin.

[0097] The TGA curves of the coating in Example 1 after curing in air atmosphere and argon atmosphere are as follows: Figure 5-6 As shown by Figure 5 It can be seen that the cured resin shows good thermal stability in an air environment below 300°C, with an initial decomposition temperature of 312°C and a residual amount close to 0%. Figure 6 It can be seen that the initial decomposition temperature of the cured resin in an argon environment is 325°C, and when the temperature is lower than 310°C, it exhibits excellent thermal stability, with a residual carbon content of 23%.

[0098] 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 1.151Mpa, and the pull-out strength of the coating in Example 2 based on the tinplate substrate was 1.096Mpa, which proved that the coating formed by the coating had the characteristics of high density and strong adhesion.

[0099] The corrosion resistance of the coating was evaluated by a scratch test on Examples 1-3 and Comparative Examples 1-8 of the present invention. The method is as follows: the prepared coating samples were respectively taken, scratched on the surface, and the scratches on the sample surface were of the same size. Then, the coating samples were placed in a salt spray test box. After 7 days of salt spray test, the surface of the samples was tested. The test standard is GB / T10125-2021. The results are shown in Table 1:

[0100] Table 1

[0101]

[0102]

[0103] 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. However, the surface coating of Comparative Examples 1-3 partially fell off and was severely corroded at the scratch points, indicating that the epoxy resin requires a reasonable ratio of bisphenol A epoxy resin, phenolic epoxy resin, and hyperbranched epoxy resin; the surface coating of Comparative Example 4 fell off severely at the scratch point, and had a tendency to derive outward, indicating that ordinary curing agents cannot achieve the corresponding effect; the surface coating of Comparative Examples 5-6 showed corrosion and severe shedding at the scratch points, indicating that the coating cured by the gradient heating method of the present invention has a higher cross-linking density, better adhesion and high temperature and humidity resistance; the coating of Comparative Example 7 fell off severely at the scratch point, and the corrosion at the scratch point was severe and the corrosion derives outward; the corrosion at the scratch point of Comparative Example 8 was severe and the corrosion derives outward.

[0104] 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:

[0105] Table 2

[0106]

[0107]

[0108] For the coatings prepared in the examples and comparative examples, the initial electrochemical impedance was 10 ^ 11Ω, 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 some bubbles appeared on the surface coating of Comparative Examples 1-3, and the electrochemical impedance dropped to a minimum of 10 ^ 6Ω; Comparative Example 4 has a large number of bubbles on the surface coating, and the electrochemical impedance value drops to 10 ^ 6Ω; Comparative Examples 5-6 have a large number of bubbles and a few bubbles respectively, and the electrochemical impedance value drops to a minimum of 10 ^ 5Ω; 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.

[0109] 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: 70 to 240 parts of epoxy resin composition and 10 to 100 parts of phenolic resin composition; The epoxy resin composition comprises 20 to 100 parts of bisphenol A epoxy resin, 10 to 40 parts of novolac epoxy resin, and 40 to 100 parts of hyperbranched epoxy resin; The phenolic resin composition is selected from phenolic resin polycondensed under acidic conditions.

2. The coating according to claim 1, characterized in that The raw material components of the coating include, by weight: 105 to 170 parts of epoxy resin composition and 30 to 50 parts of phenolic resin composition.

3. The coating according to claim 2, characterized in that The epoxy resin composition comprises 50 to 85 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 phenolic resin composition is selected from at least one of 2123 phenolic resin, 2130 phenolic resin, 2402 phenolic resin and 6216 phenolic resin.

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 silicon phosphate, silicone rubber, carbon black, iron powder, activated carbon, quartz sand, silicon dioxide, mica, polysulfide rubber, boron nitride, calcium carbonate, calcium silicate, benzoin, MXene, silsesquioxane, glass microspheres, titanium dioxide, graphite, carbon nanotubes, ferrous chloride, ferric chloride, sodium chloride, cobalt chloride, ferric oxide, ferrous oxide, cobalt oxide, aluminum oxide, nickel oxide, 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 them, and grinding and screening them to obtain epoxy resin sintered powder.

11. The preparation method according to claim 10, characterized in that: The heating and curing process is: heating to 80-280° C. and curing for 15-60 minutes.

12. The preparation method according to claim 11, characterized in that: The heating curing process is a gradient temperature rise curing process, which includes two stages: heating to 100-230° C. for curing for 15-30 min, and then heating to 230-280° C. for curing for 15-30 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 fields of home appliance manufacturing, aerospace, and microelectronic materials.

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