Polysiloxane non-stick aid, coating composition, coating, coated article having a non-stick coating, and method of forming a coating

Abstract

The application provides a polysiloxane non-stick aid, a coating composition, a coating, a coated article and a method for forming a coating, and belongs to the technical field of coatings.The polysiloxane non-stick aid has a chemical structural formula shown in formula I, and a hydroxyl or halogen-substituted silane end in the polysiloxane non-stick aid is connected to a reticular structure skeleton in a non-stick coating through a chemical bond; meanwhile, a fully alkyl-substituted silane end and an organosilicon main chain structure in the polysiloxane non-stick aid are in a free state.Through the above specific chemical structure of the polysiloxane non-stick aid, the hydrophobicity of the non-stick aid is more stable, the non-stick property of the non-stick coating is maintained when the non-stick aid is applied to the non-stick coating, meanwhile, the migration and loss of the non-stick aid are reduced, so that the non-stick durability of the non-stick coating is greatly improved, and thus the technical problem that the non-stick coating is difficult to simultaneously have safety, non-toxicity and non-stick durability is effectively solved.

Description

Technical Field

[0001] This application belongs to the field of coating technology, specifically relating to a polysiloxane non-stick additive, a coating composition, a coating, a coating layer, an article having a non-stick coating layer, and a method for forming a coating layer. Background Technology

[0002] Currently, the surfaces of common appliances on the market, such as woks, pressure cookers, blenders, and rice cookers, are coated with different types of non-stick coatings, the most common of which are fluorine coatings and ceramic coatings.

[0003] Regarding fluorinated coatings, on the one hand, the main component of fluorinated coatings is polytetrafluoroethylene (PTFE), and the raw materials used to prepare PTFE often contain a small amount of perfluorooctanoic acid (PFOA), which is carcinogenic to the human body. On the other hand, fluorinated coatings have a low operating temperature, and the specified operating temperature cannot exceed 260℃, otherwise it will release carcinogenic toxic gases.

[0004] Regarding ceramic coatings, compared to fluorine coatings, ceramic coatings have higher hardness, are less prone to scratches, have stronger inorganic weather resistance, and do not release harmful substances. However, in actual use, ceramic coatings have poor corrosion resistance and weak long-lasting non-stick properties.

[0005] In summary, existing non-stick coatings lack sufficient non-stick durability and are difficult to achieve safety and non-toxicity. Summary of the Invention

[0006] To address the technical problem of insufficient non-stick durability of current non-stick coatings, this application provides a polysiloxane non-stick additive, a coating composition, a coating, a coating layer, an article having a non-stick coating, and a method for forming the coating.

[0007] In a first aspect, embodiments of this application provide a polysiloxane non-stick additive having the chemical structural formula shown in Formula I:

[0008]

[0009] In Formula I,

[0010] R1, R2, R3, R4 and R5 may be the same or different, and each is independently selected from the first alkyl group;

[0011] R6, R7, and R8 may be the same or different, each independently selected from one of the following: a second alkyl group, a hydroxyl group, or a halogen, and at least one of R6, R7, and R8 is selected from a hydroxyl group or a halogen.

[0012] As can be seen from the above technical solution, the polysiloxane non-stick additive provided in this application is specifically a safe and non-toxic non-stick additive that does not contain fluorine. The main chain structure of this non-stick additive is an organosilicon chain. Due to the flexibility of the organosilicon chain, it has a low surface energy, thus exhibiting good anti-sticking and release properties. At the same time, the two ends of the organosilicon chain are respectively connected to silanes containing hydroxyl or halogen substitution and silanes with full alkyl substitution. When applied to non-stick coatings, the silane ends containing hydroxyl or halogen substitution can remove water molecules or hydrogen halides through chemical reactions, so that the silane ends containing hydroxyl or halogen substitution in the polysiloxane non-stick additive are connected to the network structure skeleton in the non-stick coating through chemical bonds; at the same time, the silane ends with full alkyl substitution and the organosilicon main chain structure in the polysiloxane non-stick additive remain in a free state. The specific chemical structure of this polysiloxane non-stick additive makes its hydrophobicity more stable, maintaining the non-stick properties of the coating. More importantly, the chemical bonds connecting it to the network skeleton reduce the migration and loss of the non-stick additive, thereby greatly improving the non-stick durability of the coating and effectively solving the current technical problem of insufficient non-stick durability of non-stick coatings.

[0013] Compared to commonly used non-stick additives such as methyl silicone oil, the polysiloxane non-stick additive provided in this application, comprising an organosilicon backbone and silanes with hydroxyl or halogen substitution and fully alkyl substitution respectively connected to both ends of the backbone, not only has excellent non-stick properties, but also avoids the migration and loss problems of existing non-stick additives such as methyl silicone oil. It effectively prevents the consumption of non-stick additives due to use, washing, wiping and other processes, thereby greatly improving the non-stick durability of the non-stick coating.

[0014] In some implementations, the value of n is preferably 5-25.

[0015] By controlling the value of n to be between 5 and 25, the main chain length of the polysiloxane non-stick additive is limited, thus giving it both good hydrophobicity and reactivity. Specifically, if the value of n is too small, the hydrophobicity of the polysiloxane non-stick additive will be weakened to some extent; if the value of n is too large, the steric hindrance of the polysiloxane non-stick additive will be increased, which is not conducive to the reaction with other components in the non-stick coating. At the same time, it will also affect the stability of the overall network structure skeleton of the non-stick coating to some extent.

[0016] In some implementations, n is more preferably 10-20.

[0017] In some embodiments, the first alkyl group is preferably a C1-C4 alkyl group, and / or,

[0018] The second alkyl group is preferably a C1-C4 alkyl group.

[0019] In some embodiments, the halogen is selected from chlorine, bromine, and iodine.

[0020] Polysiloxane non-stick additives do not contain fluorine, which can effectively avoid the safety and health problems caused by the denaturation of fluorinated silanes due to high temperatures, thus achieving a safe and non-toxic non-stick coating.

[0021] Secondly, embodiments of this application provide a non-stick coating composition, comprising the following components:

[0022] Silica sol solution and silane, and

[0023] The polysiloxane non-stick additive described in the first aspect.

[0024] The non-stick coating composition provided in this application, due to containing the aforementioned polysiloxane non-stick additive, correspondingly possesses the advantages of the aforementioned polysiloxane non-stick additive. Specifically, after hydrolysis of the silane in the non-stick coating composition, the alkoxy group (-OR) is converted into a hydroxyl group (-OH) to obtain silanol; the silica sol forms a cross-linked network backbone structure with the silanol and the polysiloxane non-stick additive, such that one end of the polysiloxane non-stick additive (i.e., the aforementioned silane end containing hydroxyl or halogen substitution) is chemically bonded to the network backbone structure, while the other end (i.e., the aforementioned fully alkyl-substituted silane end) is in a free state.

[0025] In general, the non-stick coating composition provided in this application can reduce the migration and loss of non-stick additives, prevent the consumption of non-stick additives due to use, washing, wiping and other processes, thereby effectively slowing down the rate at which corrosive media enter the resulting coating, improving the corrosion resistance and long-lasting non-stick properties of the resulting coating, and is safe and non-toxic.

[0026] In some embodiments, the solute in the silica sol solution is silicon dioxide with a particle size of 20-100 nm.

[0027] Selecting a particle size of 20-100nm allows for dense packing within the coating, reducing gaps and enhancing corrosion resistance and wear resistance.

[0028] In some embodiments, the weight concentration A of the silica sol solution satisfies: 20% by weight ≤ A ≤ 50% by weight.

[0029] If the weight concentration A of the silica sol solution is too low, it will result in too little solid content and poor wear resistance; if it is too high, it will result in too many particles and an insufficiently dense coating.

[0030] In some embodiments, the silane is an organosilane.

[0031] In some embodiments, the organosilane preferably includes at least one of the following: 3-glycidylpropyltrimethoxysilane, N-(β-aminoethyl)-α-aminopropyltrimethoxysilane, methyltrimethoxysilane, ethyltrimethoxysilane, methyltrimethoxysilane, propyltrimethoxysilane, and ethyltriethoxysilane.

[0032] In some embodiments, the content of the silica sol solution is 35-110 parts by weight relative to 1 part by weight of the polysiloxane non-stick additive, and the content of the silane is 25-100 parts by weight.

[0033] This formulation of the silica sol solution can improve the coating's abrasion resistance, density, and hardness.

[0034] In some embodiments, the non-stick coating composition further includes a catalyst, wherein the catalyst content is 0.5-1.5 parts by weight relative to 1 part by weight of polysiloxane non-stick additive, and the catalyst includes at least one of the following: hydrochloric acid, nitric acid, sulfuric acid, formic acid, acetic acid, and propionic acid.

[0035] The catalyst's role is to facilitate the silane hydrolysis reaction and subsequent cross-linking between components in the non-stick coating composition. After the reaction, the catalyst's composition, chemical properties, and mass remain unchanged before and after the reaction, and it does not participate in or alter the overall structure of the non-stick coating composition. Under catalytic conditions, the silane hydrolysis reaction and subsequent cross-linking between components in the non-stick coating composition can be successfully achieved, and the method is simple and the conditions are mild. This catalyst formulation can improve the non-stick properties of the coating and make it less prone to precipitation.

[0036] Thirdly, embodiments of this application provide a non-stick coating, comprising the following components:

[0037] Fillers and / or pigments, and

[0038] The non-stick coating composition described in the second aspect.

[0039] The non-stick coating provided in this application, having contained the aforementioned non-stick coating composition, possesses the advantages of the aforementioned non-stick coating composition. To meet other properties of the coating, such as filling properties and hardness, and practical application requirements, appropriate fillers can be adaptively added to the non-stick coating provided in this application. Furthermore, to provide color decoration for the coating film and improve other properties of the coating, such as weather resistance and temperature resistance, and practical application requirements, appropriate pigments can be adaptively added to the non-stick coating provided in this application.

[0040] In some embodiments, the filler includes at least one of the following: alumina, aluminum metaphosphate, titanium dioxide, mica, silicon micropowder, silicon carbide, zirconium oxide, quartz powder, zinc oxide, and copper chromate black.

[0041] The purpose of selecting the above fillers is to improve the hardness, wear resistance, and corrosion resistance of the coating.

[0042] In some embodiments, the pH value of the non-stick coating is 3-4.

[0043] A pH value of 3-4 can promote the hydrolysis of siloxanes.

[0044] In some embodiments, the solid content of the non-stick coating is 20-80% by weight.

[0045] A solid content of 20-80% by weight can improve the corrosion resistance of the coating.

[0046] In some embodiments, the filler content is 8-30 parts by weight and the pigment content is 8-25 parts by weight relative to 1 part by weight of polysiloxane nonstick additive.

[0047] This filler ratio improves the coating's corrosion resistance, while this pigment ratio enhances the coating's color gloss.

[0048] Fourthly, embodiments of this application provide a non-stick coating, including a first coating, wherein the first coating is formed from the non-stick coating described in the third aspect.

[0049] The non-stick coating provided in this application, since it includes a first coating formed by the aforementioned non-stick paint, accordingly possesses the advantages of the aforementioned non-stick paint. Overall, this non-stick coating combines excellent corrosion resistance, durable non-stick properties, and safety and non-toxicity.

[0050] The first coating of the non-stick coating generally refers to the primer, and the non-stick coating mentioned in the third aspect can be understood as component A of the non-stick coating.

[0051] In terms of performance, the non-stick coating has a hardness of 8, an adhesion of 1, and a non-stickiness of 22 (units / piece).

[0052] In some embodiments, the non-stick coating further includes a second coating applied to the surface of the first coating.

[0053] The first coating of this non-stick coating is generally the topcoat. By setting a second coating, it can resist external corrosive media and play a role in beautification and decoration.

[0054] In some embodiments, the second coating is formed from the non-stick coating composition described in the second aspect.

[0055] By applying a second coating formed from the above-described non-stick coating composition to the surface of the first coating, the coating becomes more glossy and more corrosion resistant.

[0056] In some embodiments, the non-stick coating contains a network structure framework formed by the silica sol solution and the silane through a crosslinking reaction, wherein the hydroxyl- or halogen-substituted silane ends of the polysiloxane non-stick additive are connected to the network structure framework by chemical bonds.

[0057] Polysiloxane non-stick additives are chemically bonded to the network structure skeleton, reducing the migration and loss of non-stick additives, thereby greatly improving the non-stick durability of the non-stick coating and effectively solving the technical problem of insufficient non-stick durability of current non-stick coatings.

[0058] Fifthly, embodiments of this application provide an article having a non-stick coating, the article comprising a substrate and a coating adhered to at least a portion of the surface of the substrate, the coating being the non-stick coating described in the fourth aspect.

[0059] The article with a non-stick coating provided in this application, due to containing the aforementioned non-stick coating, possesses the corresponding advantages of the aforementioned non-stick coating. In general, the article with a non-stick coating combines excellent corrosion resistance, durable non-stick properties, and safety and non-toxicity. The substrate can be a metal substrate, a glass substrate, a ceramic substrate, an enamel substrate, a polymer substrate, or a composite substrate of two or more of the above substrates. Specific examples of the metal substrate may include, but are not limited to: stainless steel substrate, aluminum substrate, aluminized substrate, galvanized substrate, and cast iron substrate. Specific examples of the polymer substrate may include, but are not limited to: polycarbonate (PC) substrate, acrylonitrile-butadiene-styrene terepolymer (ABS) substrate, polypropylene (PP) substrate, polyoxymethylene (POM) substrate, polybutylene terephthalate (PBT) substrate, and polyethylene terephthalate (PET) substrate, or two or more of these. The substrate can be various sheets or profiles, and can be installed in various molded appliances, preferably in kitchen appliances. The product can be a rice cooker, pressure cooker, microwave oven, oven, frying pan, skillet, air fryer, grill, blender, or soy milk maker.

[0060] In a sixth aspect, embodiments of this application provide a method for forming a coating on a substrate surface, the method comprising applying the coating described in the fourth aspect to at least a portion of the surface of the substrate and curing it to form a coating.

[0061] The substrate can be a metal substrate, a glass substrate, a ceramic substrate, an enamel substrate, a polymer substrate, or a composite substrate of two or more of the above substrates. The substrate can be installed in a kitchen appliance. The kitchen appliance can be a rice cooker, pressure cooker, microwave oven, oven, frying pan, skillet, air fryer, grill, blender, or soy milk maker.

[0062] In some embodiments, the temperature of the substrate is 40-60°C when the coating is applied.

[0063] In some embodiments, the curing temperature is 250-300°C, and the curing duration is 10-25 minutes. Attached Figure Description

[0064] To more clearly illustrate the technical solutions in the embodiments of this application, the accompanying drawings used in the description of the embodiments will be briefly introduced below. Obviously, the accompanying drawings described below are some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0065] Figure 1 A flowchart illustrating the preparation process of the polysiloxane non-stick additive in the embodiments of this application is shown.

[0066] Figure 2 A schematic diagram illustrating the preparation principle of the non-stick coating composition in the embodiments of this application is shown.

[0067] Figure 3 A schematic diagram of the state of the polysiloxane non-stick additive in the coating is shown in the embodiments of this application.

[0068] Figure 4 A schematic diagram of the state of existing non-stick additives in a coating is shown. Detailed Implementation

[0069] The technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only a part of the embodiments of this application, and not all of the embodiments. Based on the embodiments of this application, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of this application.

[0070] Unless otherwise specified, the terminology used herein should be understood as having the meaning commonly used in the art. Therefore, unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention pertains. In case of any conflict, this specification shall prevail.

[0071] Unless otherwise specified, all raw materials, reagents, instruments and equipment used in this invention can be purchased from the market or prepared by existing methods.

[0072] Furthermore, reference numerals and / or reference letters may be repeated in different examples in this application. Such repetition is for simplification and clarity purposes and does not in itself indicate a relationship between the various embodiments and / or settings discussed. In addition, this application provides examples of various specific processes and materials; however, those skilled in the art will recognize the application of other processes and / or the use of other materials.

[0073] In related technologies, although non-stick coatings have good anti-stick properties, on the one hand, the non-stick additives are migratory and gradually consumed during use, washing, wiping, etc., thus reducing the non-stick performance of the coating film until it loses its non-stick properties. On the other hand, although fluorosilanes are used to improve the coating's non-stick properties, high-temperature environments can cause the fluorosilanes to denature, leading to safety and health issues. In summary, existing non-stick coatings struggle to simultaneously achieve safety, non-toxicity, and durable non-stick properties. This application provides a polysiloxane non-stick additive, a coating composition, a coating, a coating layer, and an article with a non-stick coating, which can at least partially solve the current technical problem of non-stick coatings struggling to achieve both safety, non-toxicity, and durable non-stick properties.

[0074] Example 1:

[0075] In a first aspect, this embodiment provides a polysiloxane non-stick additive having the chemical structural formula shown in Formula I:

[0076]

[0077] In Formula I,

[0078] R1, R2, R3, R4 and R5 may be the same or different, and each is independently selected from the first alkyl group;

[0079] R6, R7, and R8 may be the same or different, each independently selected from one of the following: a second alkyl group, a hydroxyl group, or a halogen, and at least one of R6, R7, and R8 is selected from a hydroxyl group or a halogen.

[0080] The average molecular weight of the polysiloxane non-stick additive is generally less than or equal to 5000; this average molecular weight is determined by gel permeation chromatography.

[0081] The preferred value for n is 5-25. Specifically, the possible values ​​for n are 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, and 25.

[0082] A more preferable value for n is 10-20.

[0083] The first alkyl group is preferably a C1-C4 alkyl group, and / or,

[0084] The second alkyl group is preferably a C1-C4 alkyl group.

[0085] The “C1-C4 alkyl” in the first alkyl and / or second alkyl includes methyl, ethyl, propyl, butyl, 1-methylethyl and 1,1-dimethylethyl, etc.; preferably, the “C1-C4 alkyl” is selected from methyl or ethyl.

[0086] The halogen is selected from chlorine, bromine, and iodine. Preferably, the halogen is selected from bromine.

[0087] like Figure 1 As shown, the preparation method of the polysiloxane non-stick additive includes:

[0088] The siloxane cyclic compound was subjected to a ring-opening nucleophilic addition reaction with a halosilane under acid catalysis to obtain the first product;

[0089] The first product was hydrolyzed under weakly alkaline conditions to obtain the above-mentioned polysiloxane non-stick additive.

[0090] A polysiloxane non-stick additive with the structure of Formula I is obtained by ring-opening nucleophilic addition reaction of a siloxane cyclic compound with a halosilane under acid catalysis, followed by hydrolysis under weakly basic conditions. This preparation method is simple, has mild reaction conditions, good reproducibility, and high yield, and has broad practical application value.

[0091] The aforementioned "weakly alkaline conditions" can be understood as a pH value within the range of 7.1 to 9.0 in the reaction system where the first product undergoes hydrolysis. For example, the pH value can be 7.5, 7.8, 8.0, 8.1, 8.2, 8.3, 8.4, 8.5, 8.6, 8.7, 8.8, or other suitable pH values. Implementation of "weakly alkaline conditions" includes adding appropriate weak bases such as organic amines, ammonia, ammonium salts, or their corresponding solutions to the reaction system to adjust the reaction system to a predetermined pH range.

[0092] The process parameters for the ring-opening nucleophilic addition reaction include: (1) the mass ratio of siloxane ring to halosilane is 2-5:0.1-0.8, specifically, the mass ratio can be 2:1, 5:2, 8:1, 50:1, 25:4; (2) the reaction temperature is 55-70℃ and the reaction time is 3-4 hours, specifically, the reaction temperature and reaction time can be: 55℃ and 3 hours, 60℃ and 3 hours, 65℃ and 4 hours, 70℃ and 4 hours.

[0093] The process parameters for the hydrolysis reaction include: a reaction temperature of 40-60℃ and a reaction time of 0.2-1 hour. Specifically, the reaction temperature and reaction time can be: 40℃ and 0.2 hours, 45℃ and 1 hour, 50℃ and 0.5 hours, and 60℃ and 0.5 hours.

[0094] The siloxane cyclic body includes a dialkylsiloxane cyclic body.

[0095] Dialkylsiloxane cyclic compounds, also known as polydialkylsiloxane mixed cyclic compounds, can specifically be polydimethylsiloxane mixed cyclic compounds (DMC), polydiethylsiloxane mixed cyclic compounds, or other suitable polydialkylsiloxane mixed cyclic compounds. These dialkylsiloxane cyclic compounds can be directly obtained from commercially available products, or they can be prepared according to the polydialkylsiloxane mixed cyclic compound preparation methods disclosed in existing technologies such as Chinese Patent 201410160171.0.

[0096] The dialkylsiloxane cyclic compound has the chemical structural formula shown in Formula II:

[0097]

[0098] In Formula II, X represents the epoxy structure, and m takes values ​​from 2 to 6;

[0099] Y1 and Y2 may be the same or different, and each is independently selected from C1-C4 alkyl groups.

[0100] By controlling the value of m, the main chain length in polysiloxane non-stick additives with Formula I structure can be adjusted. Specifically, the value of m can be selected from 2, 3, 4, 5, or 6; "C1-C4 alkyl" includes methyl, ethyl, propyl, butyl, 1-methylethyl, and 1,1-dimethylethyl, etc.; preferably, "C1-C4 alkyl" is selected from methyl or ethyl; X represents the epoxy structure, specifically an oxygen-containing three-membered ring structure, etc.

[0101] The preferred value for m is 3-5.

[0102] When the value of m is controlled between 3 and 5, the main chain length of the resulting polysiloxane non-stick additive is suitable, giving it certain advantages in hydrophobicity and reactivity.

[0103] The halosilanes include one of the following: trimethylchlorosilane, trimethylbromosilane, and trimethyliodosilane.

[0104] Example 2:

[0105] Secondly, this embodiment provides a non-stick coating composition, comprising the following components:

[0106] Silica sol solution and silane, and

[0107] The polysiloxane non-stick additive described in the first aspect.

[0108] The solute in the silica sol solution is silicon dioxide with a particle size of 20-100 nm.

[0109] Selecting a particle size of 20-100nm allows for dense packing within the coating, reducing gaps and enhancing corrosion resistance and wear resistance; the specific particle sizes of silica can be 20nm, 25nm, 30nm, 35nm, 40nm, 45nm, 50nm, 55nm, 60nm, 65nm, 70nm, 75nm, 80nm, 85nm, 90nm, 95nm, and 100nm.

[0110] The weight concentration A of the silica sol solution satisfies: 20% by weight ≤ A ≤ 50% by weight.

[0111] In practical applications, the weight concentration A can be 20 wt%, 21 wt%, 22 wt%, 23 wt%, 24 wt%, 25 wt%, 26 wt%, 27 wt%, 28 wt%, 29 wt%, 30 wt%, 31 wt%, 32 wt%, 33 wt%, 34 wt%, 35 wt%, 36 wt%, 37 wt%, 38 wt%, 39 wt%, 40 wt%, 41 wt%, 42 wt%, 43 wt%, 44 wt%, 45 wt%, 46 wt%, 47 wt%, 48 wt%, 49 wt%, or 50 wt%.

[0112] The silica sol solution can be commercially available or prepared using conventional methods, such as dispersing silica in a solvent to obtain the silica sol solution. The solvent can be any water-soluble solvent, such as ethanol or water.

[0113] The silane is an organosilane.

[0114] The organosilane preferably includes at least one of the following: 3-glycidylpropyltrimethoxysilane, N-(β-aminoethyl)-α-aminopropyltrimethoxysilane, methyltrimethoxysilane, ethyltrimethoxysilane, methyltrimethoxysilane, propyltrimethoxysilane, and ethyltriethoxysilane.

[0115] The content of the silica sol solution is 35-110 parts by weight relative to 1 part by weight of polysiloxane non-stick additive, and the content of the silane is 25-100 parts by weight.

[0116] The silica sol solution can be in the form of 35 parts by weight, 40 parts by weight, 45 parts by weight, 50 parts by weight, 55 parts by weight, 60 parts by weight, 65 parts by weight, 70 parts by weight, 75 parts by weight, 80 parts by weight, 85 parts by weight, 90 parts by weight, 95 parts by weight, 100 parts by weight, 105 parts by weight, or 110 parts by weight relative to 1 part by weight of polysiloxane non-stick additive.

[0117] Relative to 1 part by weight of polysiloxane non-stick additive, the silane can be 25 parts by weight, 30 parts by weight, 35 parts by weight, 40 parts by weight, 45 parts by weight, 50 parts by weight, 55 parts by weight, 60 parts by weight, 65 parts by weight, 70 parts by weight, 75 parts by weight, 80 parts by weight, 85 parts by weight, 90 parts by weight, 95 parts by weight, or 100 parts by weight.

[0118] The non-stick coating composition further includes a catalyst, wherein the content of the catalyst is 0.5-1.5 parts by weight relative to 1 part by weight of polysiloxane non-stick additive, and the catalyst includes at least one of the following: hydrochloric acid, nitric acid, sulfuric acid, formic acid, acetic acid, and propionic acid.

[0119] The amount of catalyst can be 0.5 parts by weight, 0.6 parts by weight, 0.7 parts by weight, 0.8 parts by weight, 0.9 parts by weight, 1.0 parts by weight, 1.1 parts by weight, 1.2 parts by weight, 1.3 parts by weight, 1.4 parts by weight, or 1.5 parts by weight relative to 1 part by weight of polysiloxane non-stick additive.

[0120] Example 3:

[0121] Thirdly, this embodiment provides a non-stick coating, comprising the following components:

[0122] Fillers and / or pigments, and

[0123] The non-stick coating composition described in the second aspect.

[0124] The filler includes at least one of the following: alumina, aluminum metaphosphate, titanium dioxide, mica, silicon micro powder, silicon carbide, zirconium oxide, quartz powder, zinc oxide, and copper chromium black.

[0125] The pH value of the non-stick coating is 3-4.

[0126] In practical applications, the pH value of the non-stick coating can be 3.1, 3.2, 3.3, 3.4, 3.5, 3.6, 3.7, 3.8, 3.9, or 4.0.

[0127] The solid content of the non-stick coating is 20-80% by weight.

[0128] In practical applications, the solid content can be 20 wt%, 25 wt%, 30 wt%, 35 wt%, 40 wt%, 45 wt%, 50 wt%, 55 wt%, 60 wt%, 65 wt%, 70 wt%, 75 wt%, or 80 wt%.

[0129] The content of the filler is 8-30 parts by weight relative to 1 part by weight of polysiloxane non-stick additive, and the content of the pigment is 8-25 parts by weight.

[0130] Relative to 1 part by weight of polysiloxane non-stick additive, the content of the filler can specifically be 8 parts by weight, 9 parts by weight, 10 parts by weight, 11 parts by weight, 12 parts by weight, 13 parts by weight, 14 parts by weight, 15 parts by weight, 16 parts by weight, 17 parts by weight, 18 parts by weight, 19 parts by weight, 20 parts by weight, 21 parts by weight, 22 parts by weight, 23 parts by weight, 24 parts by weight, 25 parts by weight, 26 parts by weight, 27 parts by weight, 28 parts by weight, 29 parts by weight, or 30 parts by weight.

[0131] The pigment content relative to 1 part by weight of polysiloxane non-stick additive can specifically be 8 parts by weight, 9 parts by weight, 10 parts by weight, 11 parts by weight, 12 parts by weight, 13 parts by weight, 14 parts by weight, 15 parts by weight, 16 parts by weight, 17 parts by weight, 18 parts by weight, 19 parts by weight, 20 parts by weight, 21 parts by weight, 22 parts by weight, 23 parts by weight, 24 parts by weight, or 25 parts by weight.

[0132] The non-stick coating may contain only component A, or it may contain both component A and component B. When both components A and B are present, component A is generally used as a primer, and component B is used as a topcoat. The preparation method for component A of the non-stick coating can be as follows: silica sol solutions of different particle sizes, fillers, and pigments are mixed evenly; a certain amount of catalyst is added to adjust the pH; then a mixture of silane and polysiloxane non-stick additives is added to carry out a hydrolysis reaction, thereby obtaining component A of the non-stick coating. The preparation method for component B of the non-stick coating can be as follows: silica sol solutions of different particle sizes, silane, and polysiloxane non-stick additives are mixed evenly to carry out a hydrolysis reaction, thereby obtaining component B of the non-stick coating.

[0133] It should be noted that, to meet the actual needs of use and / or storage, the non-stick coating provided in this application can be adapted to incorporate commonly used additives in the coating industry, such as leveling agents, defoamers, viscosity modifiers, dispersants, other suitable additives, or any combination of the above additives. The leveling agent is used to promote the formation of a smoother, more uniform coating during the drying and curing process, and can be a polyacrylate-based leveling agent. The defoamer can be any commonly used substance capable of inhibiting foam formation, breaking down existing foam, and / or removing existing foam from the system, such as organopolysiloxane-based defoamers, polyether-based defoamers, and higher alcohol-based defoamers. The viscosity modifier is used to adjust the viscosity of the coating and can be one or more of polyamide wax, organobentonite, hydrogenated castor oil, metal soap, hydroxyalkyl cellulose and its derivatives, polyvinyl alcohol, and polyacrylate. The dispersant is a surfactant with both lipophilic and hydrophilic properties within its molecule, which helps prevent the aggregation of fillers, pigments, and other substances in the coating, meeting the needs of use and storage. The addition method and dosage of the above-mentioned adjuvants can be carried out in accordance with existing conventional methods, and will not be repeated in this application.

[0134] Example 4:

[0135] Fourthly, this embodiment provides a non-stick coating, including a first coating, the first coating being formed from the non-stick coating described in the third aspect.

[0136] Specifically, the first coating can be formed by applying the aforementioned non-stick coating through brushing, thermal spraying, cold spraying, electrophoretic deposition, electrostatic spraying, air pressure spraying, or other suitable methods. The thickness of the first coating can be selected according to actual application requirements. Preferably, the thickness of the first coating can be 18-35 micrometers, specifically 18 micrometers, 19 micrometers, 20 micrometers, 21 micrometers, 22 micrometers, 23 micrometers, 24 micrometers, 25 micrometers, 26 micrometers, 27 micrometers, 28 micrometers, 29 micrometers, 30 micrometers, 31 micrometers, 32 micrometers, 33 micrometers, 34 micrometers, and 35 micrometers.

[0137] The first coating of the non-stick coating generally refers to the primer, and the non-stick coating mentioned in the third aspect can be understood as component A of the non-stick coating.

[0138] In terms of performance, the non-stick coating has a hardness of 8, an adhesion of 1, and a non-stickiness of 22 (units / piece).

[0139] The non-stick coating further includes a second coating applied to the surface of the first coating.

[0140] The first layer of this non-stick coating is generally the topcoat. A second layer is applied to resist external corrosive media and to provide aesthetic and decorative effects. The aforementioned "coating" can be done using conventional methods such as brushing, spraying, dipping, electrophoretic coating, and other suitable methods.

[0141] The second coating is formed from the non-stick coating composition described in the second aspect.

[0142] By applying a second coating formed from the above-described non-stick coating composition to the surface of the first coating, the coating becomes more glossy and has stronger corrosion resistance. The thickness of the second coating can be selected according to actual usage requirements. Preferably, the thickness of the second coating can be 8-15 micrometers, specifically 8 micrometers, 9 micrometers, 10 micrometers, 11 micrometers, 12 micrometers, 13 micrometers, 14 micrometers, and 15 micrometers. The non-stick coating composition described in the second aspect can be understood as component B of the non-stick coating.

[0143] The non-stick coating contains a network structure framework formed by the silica sol solution and the silane through a crosslinking reaction. The hydroxyl- or halogen-substituted silane ends of the polysiloxane non-stick additive are connected to the network structure framework by chemical bonds. The fully alkyl-substituted silane ends and the main chain structure of the polysiloxane non-stick additive remain in a free state.

[0144] Example 5:

[0145] Fifthly, this application provides an article having a non-stick coating, the article comprising a substrate and a coating adhered to at least a portion of the surface of the substrate, the coating being the non-stick coating described in the fourth aspect.

[0146] The coating can be applied to at least a portion of the surface of the substrate (the surface to which the coating is to be formed) using conventional methods, such as one or more combinations of spraying, spin coating, curtain coating, dip coating, and roller coating. Before applying the coating, the substrate can be cleaned using conventional methods, such as degreasing and / or washing.

[0147] The coating thickness applied to the substrate surface can be selected based on the desired final coating thickness. Generally, the coating thickness applied to the substrate surface results in a final coating thickness of 25-50 micrometers, preferably 35-45 micrometers, specifically 25 micrometers, 26 micrometers, 27 micrometers, 28 micrometers, 29 micrometers, 30 micrometers, 31 micrometers, 32 micrometers, 33 micrometers, 34 micrometers, 35 micrometers, 36 micrometers, 37 micrometers, 38 micrometers, 39 micrometers, 40 micrometers, 41 micrometers, 42 micrometers, 43 micrometers, 44 micrometers, 45 micrometers, 46 micrometers, 47 micrometers, 48 ​​micrometers, 49 micrometers, and 50 micrometers.

[0148] The substrate is a metal substrate, a glass substrate, a ceramic substrate, an enamel substrate, a polymer substrate, or a composite substrate of two or more of the above substrates.

[0149] Specific examples of the metal substrate may include, but are not limited to: stainless steel substrate, aluminum substrate, aluminized substrate, zinc-plated substrate and cast iron substrate.

[0150] Specific examples of the polymer substrate may include, but are not limited to, one or more of the following: polycarbonate (PC) substrate, acrylonitrile-butadiene-styrene terpolymer (ABS) substrate, polypropylene (PP) substrate, polyoxymethylene (POM) substrate, polybutylene terephthalate (PBT) substrate, and polyethylene terephthalate (PET) substrate.

[0151] The substrate can be various plates or profiles, or it can be placed in various molded appliances, preferably in kitchen appliances.

[0152] The product in question is a kitchen utensil.

[0153] The kitchen appliances mentioned are rice cookers, pressure cookers, microwave ovens, ovens, frying pans, skillets, air fryers, grills, blenders, or soy milk makers.

[0154] Example 6:

[0155] In a sixth aspect, this embodiment provides a method for forming a coating on a substrate surface, the method comprising applying the coating described in the fourth aspect to at least a portion of the surface of the substrate and curing it to form a coating.

[0156] When the coating is applied, the temperature of the substrate is 40-60℃, including but not limited to 40℃, 45℃, 50℃, 55℃, and 60℃.

[0157] The curing temperature is 250-300℃, including but not limited to 250℃, 260℃, 250-300℃, 270℃, 275℃, 290℃, and 300℃. The curing duration is 10-25 minutes, including but not limited to 10 minutes, 15 minutes, 18 minutes, 20 minutes, and 25 minutes.

[0158] The substrate is a metal substrate, a glass substrate, a ceramic substrate, an enamel substrate, a polymer substrate, or a composite substrate of two or more of the above substrates.

[0159] Specific examples of the metal substrate may include, but are not limited to: stainless steel substrate, aluminum substrate, aluminized substrate, zinc-plated substrate, and cast iron substrate; specific examples of the polymer substrate may include, but are not limited to: one or more of the following: polycarbonate (PC) substrate, acrylonitrile-butadiene-styrene terpolymer (ABS) substrate, polypropylene (PP) substrate, polyoxymethylene (POM) substrate, polybutylene terephthalate (PBT) substrate, and polyethylene terephthalate (PET) substrate.

[0160] The base is set in the kitchen appliance.

[0161] The kitchen appliances mentioned are rice cookers, pressure cookers, microwave ovens, ovens, frying pans, skillets, air fryers, grills, blenders, or soy milk makers.

[0162] The present application is described below with reference to the accompanying drawings, specific embodiments, and effect data:

[0163] Example 7:

[0164] This embodiment provides a polysiloxane non-stick additive (denoted as polysiloxane non-stick additive A), which has the chemical structural formula shown in Formula I:

[0165]

[0166] In Formula I,

[0167] R1, R2, R3, R4, and R5 are the same, and each is independently selected from methyl groups;

[0168] R6 and R7 are the same, each independently selected from methyl; R8 is selected from hydroxyl.

[0169] n takes the value 8.

[0170] This example also provides a method for preparing the aforementioned polysiloxane non-stick additive, such as... Figure 1 As shown, Figure 1 The value of m is 4, including:

[0171] S101. A ring-opening nucleophilic addition reaction is carried out between a siloxane cyclic compound and a halosilane under acid catalysis to obtain the first product; wherein the process parameters for the ring-opening nucleophilic addition reaction are: a mass ratio of siloxane cyclic compound to halosilane of 100:25, a reaction temperature of 65℃, and a reaction time of 3.5 hours; the siloxane cyclic compound is a dimethylsiloxane cyclic compound (DMC); and the halosilane is a trimethylbromosilane.

[0172] S201. The first product is subjected to a hydrolysis reaction under weakly alkaline conditions to obtain the above-mentioned polysiloxane non-stick additive, with a total yield of up to 89%; wherein, the process parameters of the hydrolysis reaction include: reaction temperature of 45°C and reaction time of 0.5 hours.

[0173] Example 8:

[0174] Based on Example 7, this example provides a polysiloxane non-stick additive (denoted as polysiloxane non-stick additive B), which differs from Example 7 only in that: in the structural formula of the obtained polysiloxane non-stick additive, R1, R2 and R3 are the same, each independently selected from ethyl; R4 and R5 are the same, each independently selected from methyl; R6 and R7 are the same, each independently selected from ethyl; R8 is selected from hydroxyl; and all other parameters are the same.

[0175] Example 9:

[0176] Based on Example 7, this example provides a polysiloxane non-stick additive (denoted as polysiloxane non-stick additive C), which differs from Example 7 only in that: in the structural formula of the obtained polysiloxane non-stick additive, R1 is selected from propyl; R2 and R3 are the same, each independently selected from methyl; R4 and R5 are the same, each independently selected from methyl; R6 and R7 are the same, each independently selected from propyl; R8 is selected from hydroxyl; and all other parameters are the same.

[0177] Example 10:

[0178] This example provides a non-stick coating composition (denoted as non-stick coating composition A), comprising the following components:

[0179] Silica sol solution and silane, 1% by weight catalyst, and

[0180] Polysiloxane non-stick additive A prepared in Example 7.

[0181] The preparation principle of the above non-stick coating composition is as follows: Figure 2 As shown, specifically, under the action of catalysts such as hydrochloric acid, nitric acid, sulfuric acid, formic acid, acetic acid, and propionic acid, silane hydrolysis occurs first. The silica sol forms a cross-linked network skeleton with silanol and polysiloxane non-stick additive A, so that one end of polysiloxane non-stick additive A is stably connected to the network skeleton.

[0182] Example 11:

[0183] This example provides a non-stick coating composition (denoted as non-stick coating composition B), which differs from Example 10 only in that the polysiloxane non-stick additive A in Example 10 is replaced with poly18 siloxane non-stick additive B; all other parameters are the same.

[0184] Example 12:

[0185] This example provides a non-stick coating composition (denoted as non-stick coating composition C), which differs from Example 10 only in that the polysiloxane non-stick additive A in Example 10 is replaced with polysiloxane non-stick additive C; all other parameters are the same.

[0186] Example 13:

[0187] This example provides a method for forming a coating on a substrate, which is die-cast aluminum. The method includes: applying a coating A, prepared from the non-stick coating composition A obtained in Example 10 and containing fillers and pigments, to at least a portion of the surface of the die-cast aluminum substrate (such as the bottom and sides of the inner liner, or other surfaces where a coating is to be formed), and then curing it to form a coating. Specifically, the coating A is applied to the die-cast aluminum substrate using a spraying method to form a coating layer. The substrate with the coating layer is then vacuum-dried at 60°C to remove the solvent from the coating layer. Finally, it is cured at 280°C for 15 minutes in an air atmosphere with a relative humidity of 60% to obtain a non-stick coating (40-45 micrometers thick).

[0188] The composition of paint A in this example is shown in Table 1.

[0189] Table 1. Composition of Coating A

[0190]

[0191] Example 14:

[0192] This example provides a non-stick coating, which differs from Example 13 only in that the non-stick coating composition A obtained in Example 10 of Example 13 is adjusted to the non-stick coating composition B obtained in Example 11; the remaining steps and parameters are the same.

[0193] Example 15:

[0194] This example provides a non-stick coating, which differs from Example 13 only in that the non-stick coating composition A obtained in Example 10 of Example 13 is adjusted to the non-stick coating composition C obtained in Example 11; the remaining steps and parameters are the same.

[0195] Example 16:

[0196] This example provides a non-stick coating, which differs from embodiment 13 only in that the substrate of the product provided in this example is a glass substrate; the other steps and parameters are the same.

[0197] Example 17

[0198] This example provides a non-stick coating, which differs from Example 13 only in that the substrate of the product provided in this example is a ceramic substrate; the other steps and parameters are the same.

[0199] Comparative Example 1:

[0200] This example provides a non-stick coating composition (denoted as non-stick coating composition D), which differs from Example 10 only in that the polysiloxane non-stick additive A in Example 10 is replaced with the existing non-stick additive D as shown in Formula 3, whose main chain has alkylsilanes at both ends; all other parameters are the same.

[0201] This example also provides a non-stick coating, which differs from Example 10 only in that the non-stick coating composition A obtained in Example 10 in Example 13 is adjusted to the non-stick coating composition D obtained above; the remaining steps and parameters are the same.

[0202] Experimental Test

[0203] To better illustrate the performance of the polysiloxane non-stick additive and coating composition provided in this application, the non-stick coatings obtained in Examples 13-17 and Comparative Example 1 were subjected to experimental tests on coating performance.

[0204] Test standards: The hardness of the coating was determined using the method specified in GB / T6739-2006; the adhesion of the coating was determined using the cross-cut test according to the method specified in GB / T9286-1998; the non-stick properties of the coating were tested using the fried egg test method described in HG / T 4563-2013. Test results are shown in Table 2; a schematic diagram of the state of polysiloxane non-stick additive A in the coating obtained from paint A is shown below. Figure 3 As shown, Figure 3 middle The polysiloxane non-stick additive A contains silane terminals with hydroxyl or halogen substitutions that are covalently linked to the network backbone; a schematic diagram of the state of the existing non-stick additive D in the coating obtained by coating D is shown below. Figure 4 As shown, Figure 4 middle This represents the "alkylsilane terminator" in the existing non-stick additive D.

[0205] Table 2 Coating Test Results

[0206]

[0207]

[0208] Based on the above method for testing non-stick properties, the products with non-stick coatings obtained in Examples 13-17 and Comparative Example 1 were continuously rinsed with neutral water, acidic water with pH 5, and alkaline water with pH 8 for 10 days, respectively, to simulate the consumption of non-stick additives in the coating during actual processes. The non-stick properties were tested on the 1st, 5th, and 10th days after the start of rinsing according to the egg-frying test method described in HG / T4563-2013. The test results are shown in Tables 3-5.

[0209] Table 3 Results of non-stick durability test under neutral water conditions

[0210]

[0211] Table 4 Results of non-stick durability test under acidic water conditions

[0212]

[0213] Table 5 Results of non-stick durability test under alkaline water conditions

[0214]

[0215]

[0216] As shown in Table 2-5, the coating obtained by using the non-stick additive provided in this application has both excellent non-stick properties and long-lasting non-stick performance. Its hardness and adhesion meet the requirements for use, solving the technical problem that current non-stick coatings are difficult to balance safety and non-toxicity with long-lasting non-stick performance. At the same time, it maintains excellent performance under different usage environments such as acid washing and alkaline washing, and is suitable for different usage environments, with broad practical application value.

[0217] It should be understood that the endpoints and any values ​​of the ranges disclosed herein are not limited to the precise ranges or values, and these ranges or values ​​should be understood to include values ​​close to these ranges or values. For numerical ranges, the endpoint values ​​of the various ranges, the endpoint values ​​of the various ranges and individual point values, and individual point values ​​can be combined with each other to obtain one or more new numerical ranges, which should be considered as specifically disclosed herein.

[0218] It should be noted that in this document, relational terms such as "first" and "second" are used merely to distinguish one entity or operation from another, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Furthermore, the terms "comprising," "including," or any other variations are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such a process, method, article, or apparatus. Additionally, the term "and / or" as used herein is merely a description of the relationship between related objects, indicating that three relationships can exist. For example, A and / or B can represent: A alone, A and B simultaneously, or B alone.

[0219] The above description is merely a specific embodiment of the present invention, enabling those skilled in the art to understand or implement the invention. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the invention. Therefore, the present invention is not to be limited to the embodiments shown herein, but is to be accorded the widest scope consistent with the principles and novel features claimed herein.

Claims

1. A non-stick coating composition characterized in that, The composition comprises: a silica sol solution, a silane, and a polysiloxane non-stick agent, the content of the silica sol solution is 35-110 parts by weight, and the content of the silane is 25-100 parts by weight, relative to 1 part by weight of the polysiloxane non-stick agent; the polysiloxane non-stick agent has a chemical structural formula shown in Formula I: (Formula I) in Formula I, R1, R2, R3, R4, and R5 are the same or different, and each is independently selected from a first alkyl group; R6, R7, and R8 are the same or different, and each is independently selected from one of a second alkyl group, a hydroxyl group, and a halogen, and at least one of R6, R7, and R8 is selected from a hydroxyl group or a halogen, and the halogen is selected from one of chlorine, bromine, and iodine, and n has a value of 5-25; the solute of the silica sol solution is silica with a particle size of 20-100 nm; a network structure skeleton formed by a cross-linking reaction of the silica sol solution and the silane, a silane end of the polysiloxane non-stick agent substituted by a hydroxyl group or a halogen is connected to the network structure skeleton by a chemical bond, and a silane end of the polysiloxane non-stick agent substituted by a full alkyl group and a main chain structure are in a free state.

2. The non-stick coating composition according to claim 1, characterized in that, n has a value of 10-20.

3. The non-stick coating composition according to claim 1, characterized in that, the first alkyl group is a C1-C4 alkyl group, and / or the second alkyl group is a C1-C4 alkyl group. The weight concentration A of the silica sol solution satisfies: 40% by weight ≤ A ≤ 55% by weight.

4. The non-stick coating composition of claim 1, wherein, The silane is an organic silane.

5. The non-stick coating composition according to claim 1, wherein The organic silane comprises at least one of 3-glycidylpropyltrimethoxysilane, N-(β-aminoethyl)-α-aminopropyltrimethoxysilane, methyltrimethoxysilane, ethyltrimethoxysilane, propyltrimethoxysilane, and ethyltriethoxysilane.

6. The non-stick coating composition according to claim 5, characterized in that, The composition further comprises a catalyst, the content of the catalyst is 0.5-1.5 parts by weight, relative to 1 part by weight of the polysiloxane non-stick agent, and the catalyst comprises at least one of hydrochloric acid, nitric acid, sulfuric acid, formic acid, acetic acid, and propionic acid.

7. The non-stick coating composition according to any one of claims 1 to 6, characterized in that, The composition comprises:

8. A non-stick coating, characterized in that, a filler and / or a pigment, and the non-stick coating composition according to any one of claims 1-7. The filler comprises at least one of aluminum oxide, aluminum metaphosphate, titanium oxide, mica, silicon powder, silicon carbide, zirconium oxide, quartz powder, zinc oxide, and copper-chromium black.

9. The non-stick coating according to claim 8, characterized in that, The pH value of the non-stick coating is 3-4.

10. The non-stick coating according to claim 8, characterized in that, The solid content of the non-stick coating is 20-80% by weight.

11. The non-stick coating according to claim 8, characterized in that, The content of the filler is 8-30 parts by weight, and the content of the pigment is 8-25 parts by weight, relative to 1 part by weight of the polysiloxane non-stick agent.

12. Non-stick coating according to any one of claims 8 to 11, characterized in that The first coating layer is formed by the non-stick coating according to any one of claims 8-12.

13. A non-stick coating characterized in that, The second coating layer is coated on the surface of the first coating layer.

14. The non-stick coating according to claim 13, characterized in that, The second coating layer is formed by the non-stick coating composition according to any one of claims 6-12.

15. The non-stick coating according to claim 14, characterized in that The non-stick coating contains a network structure skeleton formed by a cross-linking reaction of the silica sol solution and the silane, and a silane end of the polysiloxane non-stick agent substituted by a hydroxyl group or a halogen is connected to the network structure skeleton by a chemical bond.

16. Non-stick coating according to any one of claims 13 to 15, characterized in that ​ 17. An article having a non-stick coating, characterized by, The article comprises a substrate and a coating attached to at least a portion of the surface of the substrate, the coating being a non-stick coating as described in any one of claims 13-16.

18. A method for forming a coating on a substrate surface, the method comprising applying and curing a non-stick coating of any one of claims 8-12 to at least a portion of the substrate surface to form the coating.

19. The method of claim 18, wherein, When the coating is applied, the temperature of the substrate is 40-60℃.

20. The method of claim 18 or 19, wherein, The curing temperature is 250-300℃, and the curing duration is 10-25 minutes.

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