High-wear-resistance inorganic non-stick coating, preparation method and application thereof

Abstract

The application relates to the field of paint, and discloses a high-wear-resistance inorganic non-stick paint, a preparation method and application thereof. The high-wear-resistance inorganic non-stick paint comprises: a primer paint: 50-75 parts of silica sol color paste, 10-20 parts of siloxane, 1-3 parts of acid catalyst, 3-7 parts of silane coupling agent, 1-2 parts of leveling agent and 2-5 parts of non-stick additive; and a topcoat paint: 45-70 parts of silica sol, 13-21 parts of siloxane, 1-3 parts of acid catalyst, 1-2 parts of leveling agent and 2-5 parts of non-stick additive; in the primer paint, the silica sol color paste comprises the following raw materials in parts by weight: 40-70 parts of silica sol, 10-15 parts of color powder, 10-20 parts of anti-chipping ceramic filler and 1-5 parts of wear-resistant filler. The high-wear-resistance inorganic non-stick paint comprises independent primer paint and topcoat paint, the paint does not contain organic solvents, is practical, environment-friendly and simple to produce, has the advantages of high hardness, good non-stick property after high-wear resistance, high-temperature resistance, and a simple preparation method, and is easier to produce on a large scale.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of paint, in particular to a high wear-resistant inorganic non-stick paint and its preparation method and application. BACKGROUND

[0002] Non-stick paint is an important chemical product, which is a coating material with low surface energy and anti-adhesion properties, which can be applied to iron, steel and aluminum surfaces, has good non-stickiness, and can directly fry eggs at 170-210 DEG C without adding cooking oil and easily fall off. Non-stick paint not only has good non-stickiness, but also has properties such as cold and hot impact resistance and wear resistance. The coating can modify the surface of the metal to improve the performance of the base material and prolong the service life of the metal base material.

[0003] Non-stick coating can be divided into two categories: organic non-stick coating and inorganic non-stick coating, which is widely used in cookware. At present, the coating of non-stick cookware on the market is mostly polytetrafluoroethylene and other fluoropolymer resin coating. Although its surface tension is much smaller than that of other solid materials, it has a certain impact on the environment and even human health. For example, PFOA is a necessary additive in the production process of Teflon coating. It may decompose at high temperatures and release many harmful gases, causing some respiratory sensitive animals to die, and its chemical properties are relatively stable, which will exist in the human body and natural environment for a long time, and its toxicity to the human body is not yet determined. The U.S. Environmental Protection Agency has decided to order eight chemical companies including DuPont to gradually reduce or stop producing ammonium perfluorooctanoate PFOA, a key component of Teflon coating. Therefore, inorganic coating will gradually replace organic coating.

[0004] On the other hand, the bonding force between polyfluororesin and cookware substrate is relatively weak. When the coating is directly contacted with the spatula and scouring pad during daily cooking and washing, it is easy to cause peeling. Although the coating has excellent non-stick properties, the non-stick properties will decrease rapidly after repeated friction, and the non-stick pot will lose its non-stick properties. Therefore, necessary improvements need to be made from the aspects of raw material formula, preparation process, etc. to meet the actual application requirements. In addition, the high temperature resistance of polyfluororesin coating is very weak, and it usually reaches its limit at about 260 DEG C. Therefore, a new type of non-stick coating with high wear resistance and good non-stickness after wear is needed. SUMMARY

[0005] In order to solve the above technical problems, the present application provides a high wear-resistant inorganic non-stick paint and its preparation method and application. The high wear-resistant inorganic non-stick paint of the present application includes independent primer paint and topcoat paint. The paint does not add organic solvent, is practical and environmentally friendly, and is simple to produce. It has the advantages of high hardness, good non-stickness after wear, and high temperature resistance, and the preparation method is simple, which is more easy to mass production.

[0006] The specific technical scheme of the present application is:

[0007] In the first aspect, the present application provides a high wear-resistant inorganic non-stick coating, which comprises the following raw materials by weight:

[0008] The primer coating: silica sol color paste 50-75 parts, siloxane 10-20 parts, acid catalyst 1-3 parts, silane coupling agent 3-7 parts, leveling agent 1-2 parts, and non-stick aid 2-5 parts.

[0009] The topcoat coating: silica sol 45-70 parts, siloxane 13-21 parts, acid catalyst 1-3 parts, leveling agent 1-2 parts, and non-stick aid 2-5 parts.

[0010] The silica sol color paste comprises the following raw materials by weight: silica sol 40-70 parts, color powder 10-15 parts, anti-chipping ceramic filler 10-20 parts, and wear-resistant filler 1-5 parts.

[0011] The high wear-resistant inorganic non-stick coating of the present application is divided into independent primer coating and topcoat coating. The primer coating as a coating component mainly improves the appearance effect, which can provide the color required by the user (silica sol color paste), and fill the pores on the surface of the substrate, making the coating more smooth and flat, and improving the gloss of the coating. At the same time, after the primer coating fills the pores of the substrate, it has many anchor points with the substrate, which can further increase the contact area with the substrate, thereby improving the adhesion of the coating. The topcoat coating of the present application as the part directly contacting with the external environment has excellent wear resistance, which can ensure the service life of the cookware, and at the same time has good chemical inertness, which can effectively resist the corrosion of acid, alkali, salt and other chemical substances, and has low surface energy, which can effectively reduce the adhesion of pollutants.

[0012] Specifically, in the primer coating and topcoat coating, the present application takes silica sol and siloxane as main raw materials, forms inorganic ceramic coating through solvent-gel reaction under the action of acid catalyst, and then realizes that the coating can withstand tens of thousands of wear tests by using wear-resistant fillers in the coating. The siloxane is hydrolyzed with water during the curing process, converting alkoxy into hydroxyl, which is more prone to dehydrating condensation reaction with the hydroxyl of silica sol or the hydroxyl of the rest of the hydrolyzed siloxane, and continuously reacts to form a network structure with Si-O-Si as the skeleton. During this period, the anti-chalking fillers and wear-resistant fillers in the silica sol color paste are also uniformly embedded in the network, and the water in the coating is removed by high-temperature baking, so that the condensed hydroxyls can further condense, thereby forming a dense high-hardness and high-wear-resistant coating, so that the coating is unbreakable. Therefore, the high-wear-resistant inorganic non-stick coating of the present application has better wear resistance and high-temperature resistance compared with polyfluororesin coating. It not only has excellent non-stickness after being rubbed by a scouring pad under a force of 15N for 20,000 or even more times, but also does not leak the base material after being rubbed for 120,000 or even more times, has relatively stable heat resistance below 400℃, no smoke, no toxic gas, no discoloration, no obvious change in the coating when the temperature suddenly changes, adhesion up to 0 level, hardness up to 9H, and easy-to-clean surface.

[0013] Further preferably, in the silica sol color paste: the silica sol is selected from alkaline silica sol and acidic silica sol; the color powder is inorganic color powder such as titanium dioxide, carbon black, and iron oxide; the anti-chalking filler is selected from whisker silicon, whisker alumina, and whisker silicon nitride; and the wear-resistant filler is selected from silicon carbide and corundum.

[0014] As a preference, in the primer coating: the siloxane is selected from methyltrimethoxysilane, ethyltrimethoxysilane, and phenyltrimethoxysilane; the acid catalyst is selected from formic acid solution, acetic acid solution, and hydrochloric acid solution; the leveling agent is selected from polydimethylsiloxane and polymethylphenylsiloxane; the non-stick aid is selected from methyl silicone oil and small-molecular-weight hydroxyl-terminated methyl silicone oil (molecular weight between 300 and 2000); and the silane coupling agent is selected from KH-550, KH-560, and KH-570.

[0015] As a preference, in the topcoat coating: the silica sol is alkaline silica sol; the siloxane is selected from methyltrimethoxysilane, ethyltrimethoxysilane, and phenyltrimethoxysilane; the acid catalyst is selected from formic acid solution, acetic acid solution, and hydrochloric acid solution; the leveling agent is selected from polydimethylsiloxane and polymethylphenylsiloxane; and the non-stick aid is selected from methyl silicone oil and small-molecular-weight hydroxyl-terminated methyl silicone oil (molecular weight between 300 and 2000).

[0016] In a second aspect, the application provides a preparation method of the high wear-resistant inorganic non-stick coating, which specifically comprises the following steps: 1) preparation of the primer coating: uniformly mix the silica sol color paste and the acid catalyst, so that the pH of the silica sol system is suitable for maturation, and then add the leveling agent, the silane coupling agent, the non-stick additive and the siloxane, and stir and mature; after the siloxane is added into the system, it first undergoes a hydrolysis reaction under the catalysis of the acid to generate silicon hydroxyl groups, and then the silicon hydroxyl groups and the hydroxyl groups obtained by the hydrolysis of the silica sol, the remaining siloxane or the non-stick additive undergo a dehydration condensation reaction to generate high-strength Si-O-Si bonds, and with the continuous maturation, the space network structure is formed, and the fillers in the color paste are inserted into the space network structure, thereby obtaining the primer coating.

[0017] 2) preparation of the topcoat coating: uniformly mix the silica sol and the acid catalyst, and then add the siloxane, the leveling agent and the non-stick additive, and stir and mature; the reaction process is similar to that of the primer coating, thereby obtaining the topcoat coating.

[0018] Preferably, in 1), the preparation method of the silica sol color paste comprises: mixing the silica sol, the color powder, the anti-chipping ceramic filler and the wear-resistant filler, and then ball milling, thereby obtaining the silica sol color paste.

[0019] Preferably, in 1), the stirring and maturation is performed at a rotation speed of 240-260 rpm for 4-6 h.

[0020] Preferably, in 2), the stirring and maturation is performed at a rotation speed of 240-260 rpm for 4-6 h.

[0021] In a third aspect, the application provides an application of the high wear-resistant inorganic non-stick coating in the preparation of a non-stick coating of a cookware, which comprises the following steps: sandblasting the cookware substrate, cleaning the substrate, preheating, spraying the primer coating, spraying the topcoat coating, and sintering; in order to make the primer and the substrate have more anchor points and increase the adhesion, the substrate is cleaned after sandblasting; in order to remove the dust and grease on the surface of the substrate and ensure that there are no particles and shrinkage holes after the coating is dried, the substrate is preheated; when the primer coating is sprayed, at least 2 layers of the primer coating are sprayed, and then at least 1 layer of the topcoat coating is sprayed on the primer coating without surface drying; after the surface is dried, the coating is sintered; if the surface is not dried, the water in the coating cannot be fully volatilized, which may cause the coating to be easy to crack and chip; during the high-temperature sintering process, the unreacted silicon hydroxyl groups will further condense, and the silicon hydroxyl groups connected with the substrate will also condense with the hydroxyl groups on the substrate to be connected in the form of bonding, which is very firm; after sintering, the high wear-resistant inorganic non-stick coating is obtained by slowly cooling in the room.

[0022] In the method, the preparation process of the primer coating and the topcoat is simple, the raw materials are only put into a reaction bottle once for aging and filtering, and then the primer coating and the topcoat can be used, the operation is simple, and heating and temperature control are not needed, energy is saved, the primer coating does not need to be surface dried after spraying, and the topcoat can be directly sprayed and then placed in a drying device, and the method is fast and convenient.

[0023] Preferably, the preheating temperature is 40-60℃.

[0024] The preheating can effectively remove moisture and condensate on the surface of the substrate, is beneficial to thermal activation of the surface, and promotes the physical and chemical action between the substrate and the coating, but the preheating temperature cannot be too high or too low, too high can cause roughness of the coating and reduction of gloss, and too low can cause sagging and shrinkage of the coating.

[0025] Preferably, the primer coating and the topcoat are pre-filtered through a 300-500 mesh filter.

[0026] Preferably, the primer coating has 2-3 layers, and the topcoat has 1-2 layers.

[0027] Preferably, the drying temperature is 140-160℃, and the time is 3-10min.

[0028] Preferably, the sintering temperature is 240-280℃, and the time is 5-20min.

[0029] Compared with the prior art, the method has the following advantages:

[0030] (1) The coating of the application does not contain organic solvents, is practical and environmentally friendly, and is simple to produce, has excellent non-stickiness after being rubbed by a hundred times of rubbing cloth under a force of 15N for 20,000 or more times, does not leak the substrate after being rubbed for 120,000 or more times, has relatively stable heat resistance below 400℃, does not produce smoke, toxic gas or discoloration when burning, does not have obvious changes in the coating when the temperature suddenly changes, has an adhesion of 0 level, a hardness of 9H, and an easy-to-clean surface.

[0031] (2) In the method, the preparation process of the primer coating and the topcoat is simple, the raw materials are only put into a reaction bottle once for aging and filtering, and then the primer coating and the topcoat can be used, the operation is simple, and heating and temperature control are not needed, energy is saved, the primer coating does not need to be surface dried after spraying, and the topcoat can be directly sprayed and then placed in a drying device, and the method is fast and convenient.

[0032] (3) The low-surface-energy group in the non-stick agent in the coating is fixed on the coating by dehydration condensation, compared with physical embedding, the method can firmly fix the low-surface-energy group on the coating, and greatly improves the long-acting non-stick performance of the coating. DETAILED DESCRIPTION

[0033] The application will be further described in connection with the following examples.

[0034] General examples

[0035] First, a high wear-resistant inorganic non-stick coating, which includes a primer coating and a topcoat coating. Specifically:

[0036] The primer coating includes the following raw materials by weight: silica sol color paste 50-75 parts, siloxane 10-20 parts, acid catalyst 1-3 parts, silane coupling agent 3-7 parts, leveling agent 1-2 parts, non-stick aid 2-5 parts.

[0037] In some preferred embodiments, the primer coating: the silica sol color paste includes the following raw materials by weight: silica sol 40-70 parts, color powder 10-15 parts, anti-chipping ceramic filler 10-20 parts and wear-resistant filler 1-5 parts.

[0038] In some more preferred embodiments, the silica sol color paste: the silica sol is selected from basic silica sol, acidic silica sol, and the solid content is 30-35%; the color powder is titanium dioxide, carbon black, iron oxide and other inorganic color powder; the anti-chipping ceramic filler is selected from whisker silicon, whisker alumina and whisker silicon nitride; the wear-resistant filler is selected from silicon carbide and corundum.

[0039] In some preferred embodiments, the primer coating: the siloxane is selected from methyltrimethoxysilane, ethyltrimethoxysilane and phenyltrimethoxysilane; the acid catalyst is selected from formic acid solution, acetic acid solution and hydrochloric acid solution; the leveling agent is selected from polydimethylsiloxane and polymethylphenylsiloxane; the non-stick aid is selected from methyl silicone oil, small molecular weight hydroxyl-terminated methyl silicone oil (molecular weight between 300-2000); the silane coupling agent is selected from KH-550, KH-560 and KH-570.

[0040] The topcoat coating includes the following raw materials by weight: silica sol 45-70 parts, siloxane 13-21 parts, acid catalyst 1-3 parts, leveling agent 1-2 parts, non-stick aid 2-5 parts.

[0041] In some preferred embodiments, the topcoat coating: the silica sol is basic silica sol; the siloxane is selected from methyltrimethoxysilane, ethyltrimethoxysilane and phenyltrimethoxysilane; the acid catalyst is selected from formic acid solution, acetic acid solution and hydrochloric acid solution; the leveling agent is selected from polydimethylsiloxane, polymethylphenylsiloxane; the non-stick aid is selected from methyl silicone oil, small molecular weight hydroxyl-terminated methyl silicone oil (molecular weight between 300-2000).

[0042] Second, a preparation method of a high wear-resistant inorganic non-stick coating, which specifically includes the following steps:

[0043] 1) Preparation of primer coating: mix the silica sol color paste with acid catalyst, add leveling agent, silane coupling agent, non-stick additive and siloxane, stir and mature to obtain primer coating.

[0044] In some preferred embodiments, in 1), the preparation method of the silica sol color paste comprises: mixing silica sol, color powder, anti-chipping ceramic filler and wear-resistant filler by ball milling to obtain silica sol color paste.

[0045] In some preferred embodiments, in 1), the stirring and maturing speed is 240-260 rpm; the time is 4-6 h.

[0046] 2) Preparation of topcoat coating: mix the silica sol with acid catalyst, add siloxane, leveling agent, non-stick additive, stir and mature to obtain topcoat coating.

[0047] In some preferred embodiments, in 2), the stirring and maturing speed is 240-260 rpm; the time is 4-6 h.

[0048] Finally, the application of a layer of high-wear-resistant inorganic non-stick coating in the preparation of cookware non-stick coating, comprising the following steps: after sandblasting and cleaning treatment of the cookware substrate, preheating, first spraying at least 2 layers of primer coating, then wet spraying at least 1 layer of topcoat coating, drying, sintering to obtain high-wear-resistant inorganic non-stick coating.

[0049] In some preferred embodiments, the preheating temperature is 40-60℃.

[0050] In some preferred embodiments, the primer coating and topcoat coating are pre-filtered through a 300-500 mesh filter screen.

[0051] In some preferred embodiments, the number of layers of primer coating sprayed is 2-3 layers, and the number of layers of topcoat coating wet sprayed is 1-2 layers.

[0052] In some preferred embodiments, the drying temperature is 140-160℃, and the time is 3-10 min.

[0053] In some preferred embodiments, the sintering temperature is 240-280℃, and the time is 5-20 min.

[0054] Specific embodiments and comparative examples

[0055] Silica sol color paste preparation example:

[0056] Example 1

[0057] 65g of the basic silica sol, 13g of carbon black, 12g of whisker silicon and 10g of silicon carbide were placed in a grinding tank, 70g of zirconium beads were added for grinding, the rotation speed was set to 500rpm, and after grinding for 4h, the particle size was less than 20μm, and the silica sol color paste was prepared.

[0058] Comparative Example 1

[0059] 65g of the basic silica sol, 16g of carbon black, 19g of whisker silicon were placed in a grinding tank, 70g of zirconium beads were added for grinding, the rotation speed was set to 500rpm, and after grinding for 4h, the particle size was less than 20μm, and the silica sol color paste was prepared.

[0060] Comparative Example 2

[0061] 65g of the basic silica sol, 13g of carbon black, 12g of whisker silicon and 10g of silicon carbide were placed in a grinding tank, 70g of zirconium beads were added for grinding, the rotation speed was set to 500rpm, and after grinding for 4h, the particle size was less than 20μm, and the silica sol color paste was prepared.

[0062] Coating Preparation Example:

[0063] Example 2

[0064] In the reaction bottle, 54.6g of the silica sol color paste prepared in Example 1 and 3g of 25% concentration formic acid solution were mixed and stirred, the pH was tested to be 3.62, then 1.8g of polydimethylsiloxane, 4.2g of KH-560, 2.8g of methyl silicone oil (the structural formula is CH3[-Si(CH3)2-O-] n CH3, n=40-70, molecular weight is 3000-5000), 20.8g of methyl trimethoxysilane were added, the rotation speed was adjusted to 260rpm, and the primer coating was prepared after aging for 4h. In the reaction bottle, 48.2g of basic siloxane silica sol, 2.1g of 50% concentration formic acid were mixed and stirred, the pH was tested to be 3.6, then 18.2g of methyl trimethoxysilane, 1.4g of polydimethylsiloxane, 3.6g of methyl silicone oil (the structural formula is CH3[-Si(CH3)2-O-] n CH3, n=40-70, molecular weight is 3000-5000) were added, the rotation speed was adjusted to 260rpm, and the topcoat coating was prepared after aging for 4h. After the aluminum plate was sandblasted and cleaned, it was preheated to 50℃, the aged primer coating and topcoat coating were filtered through a 400 mesh filter, and then poured into the spray gun tank, the primer coating was evenly sprayed on the substrate for 3 layers, and then the topcoat coating was wet sprayed for 1 layer, placed in a 150℃ oven for 5min of surface drying, and then moved to a 260℃ oven for high temperature sintering for 10min, thereby obtaining a high wear-resistant inorganic non-stick coating with excellent performance.

[0065] Comparative Example 3

[0066] The difference between Example 2 is that the silica sol color paste of Example 1 is replaced by the same amount of silica sol color paste of Comparative Example 1 when preparing the primer coating, and the rest of the steps and materials and compositions are consistent with Example 2, which specifically includes:

[0067] In the reaction bottle, 54.6g of the silica sol color paste prepared in Example 2 and 3g of 25% formic acid solution were added, mixed and stirred, and the pH was tested to be 3.64. Then, 1.8g of polydimethylsiloxane, 4.2g of KH-560, 2.8g of methyl silicone oil (with the structural formula CH3[-Si(CH3)2-O-] n CH3, n=40-70, molecular weight 3000-5000), and 20.8g of methyltrimethoxysilane were added, the rotation speed was adjusted to 260rpm, and the primer coating was prepared after aging for 4 hours. In the reaction bottle, 48.2g of basic siloxane silica sol and 2.1g of 50% formic acid were added, mixed and stirred, and the pH was tested to be 3.6. Then, 18.2g of methyltrimethoxysilane, 1.4g of polydimethylsiloxane, and 3.6g of methyl silicone oil (with the structural formula CH3[-Si(CH3)2-O-] n CH3, n=40-70, molecular weight 3000-5000) were added, the rotation speed was adjusted to 260rpm, and the topcoat coating was prepared after aging for 4 hours. After sandblasting and cleaning treatment, the aluminum plate was preheated to 50°C. The aged primer coating and topcoat coating were filtered through a 400 mesh filter and poured into the spray gun tank. The primer coating was evenly sprayed on the substrate for 3 layers, and then the topcoat coating was wet sprayed for 1 layer. The coating was placed in a 150°C oven for 5 minutes of surface drying, and then moved to a 260°C oven for high temperature sintering for 10 minutes, thereby obtaining an inorganic non-stick coating.

[0068] Comparative Example 4

[0069] The difference between Example 2 is that the silica sol color paste of Example 1 is replaced by the same amount of silica sol color paste of Comparative Example 2 when preparing the primer coating, and the rest of the steps and materials and compositions are consistent with Example 2, which specifically includes:

[0070] In the reaction bottle, 54.6g of the silica sol color paste prepared in Example 2 and 3g of 25% formic acid solution were added, mixed and stirred, and the pH was tested to be 3.64. Then, 1.8g of polydimethylsiloxane, 4.2g of KH-560, 2.8g of methyl silicone oil (with the structural formula CH3[-Si(CH3)2-O-] nCH3, n = 40-70, molecular weight 3000-5000), 20.8g methyl trimethoxysilane was added, the rotation speed was adjusted to 260rpm, and the primer coating was prepared after aging for 4 hours. In the reaction bottle, 48.2g of the basic siloxane silica sol, 2.1g of 50% concentration formic acid were added, mixed and stirred, the pH was measured to be 3.6, then 18.2g of methyl trimethoxysilane, 1.4g of polydimethylsiloxane, 3.6g of methyl silicone oil (the structural formula is CH3[-Si(CH3)2-O-] n CH3, n = 40-70, molecular weight 3000-5000) was added, the rotation speed was adjusted to 260rpm, and the topcoat coating was prepared after aging for 4 hours. After the aluminum plate was sandblasted and cleaned, it was preheated to 50°C, and the primer coating and the topcoat coating that had been aged were filtered through a 400-mesh filter and poured into the spray gun tank. The primer coating was uniformly sprayed on the substrate for 3 layers, and then the topcoat coating was wet sprayed for 1 layer. The coating was placed in a 150°C oven for 5 minutes of surface drying, and then moved to a 260°C oven for high-temperature sintering for 10 minutes, thereby obtaining the inorganic non-stick coating.

[0071] Example 3

[0072] The difference from Example 2 is that 2.8g of methyl silicone oil (the structural formula is CH3[-Si(CH3)2-O-] n CH3, n = 40-70, molecular weight 3000-5000) was replaced with 2.8g of hydroxyl silicone oil (the structural formula is HO[-Si(CH3)2-O-] n OH, n = 5-30, molecular weight 300-2000) when preparing the primer coating, and 3.6g of methyl silicone oil (the structural formula is CH3[-Si(CH3)2-O-] n CH3, n = 40-70, molecular weight 3000-5000) was replaced with 3.6g of hydroxyl silicone oil (the structural formula is HO[-Si(CH3)2-O-] n OH, n = 5-30, molecular weight 300-2000) when preparing the topcoat coating, and the remaining steps, materials and compositions were consistent with Example 2, which specifically included:

[0073] In the reaction bottle, 54.6g of the silica sol color paste prepared in Example 1 and 3g of 25% concentration formic acid solution were added, mixed and stirred, the pH was measured to be 3.61, then 1.8g of polydimethylsiloxane, 4.2g of KH-560, 2.8g of hydroxyl silicone oil (the structural formula is HO[-Si(CH3)2-O-] nOH, n = 5-30, molecular weight 300-2000), 20.8 g of methyltrimethoxysilane was added, the rotation speed was adjusted to 260 rpm, and the primer coating was prepared after aging for 4 hours. In the reaction bottle, 48.2 g of the basic siloxane silica sol, 2.1 g of 50% concentration formic acid were added, mixed and stirred, the pH was measured to be 3.6, and then 18.2 g of methyltrimethoxysilane, 1.4 g of polydimethylsiloxane, and 3.6 g of hydroxyl silicone oil (with the structural formula HO[-Si(CH3)2-O-] n OH, n = 5-30, molecular weight 300-2000), 20.8 g of methyltrimethoxysilane was added, the rotation speed was adjusted to 260 rpm, and the primer coating was prepared after aging for 4 hours. In the reaction bottle, 48.2 g of the basic siloxane silica sol, 2.1 g of 50% concentration formic acid were added, mixed and stirred, the pH was measured to be 3.6, and then 18.2 g of methyltrimethoxysilane, 1.4 g of polydimethylsiloxane, and 3.6 g of hydroxyl silicone oil (with the structural formula HO[-Si(CH3)2-O-]

[0074] Comparative Example 5

[0075] The difference from Example 2 is only that the aging time of the primer coating is increased from 4 hours to 5 hours, and the aging time of the top coating is increased from 4 hours to 5 hours, and the other steps and materials and compositions are consistent with Example 2, which specifically includes:

[0076] In the reaction bottle, 54.6 g of the silica sol color paste prepared in Example 1 and 3 g of 25% concentration formic acid solution were added, mixed and stirred, the pH was measured to be 3.62, and then 1.8 g of polydimethylsiloxane, 4.2 g of KH-560, and 2.8 g of methyl silicone oil (with the structural formula CH3[-Si(CH3)2-O-] n CH3, n = 40-70, molecular weight 3000-5000), 20.8 g of methyltrimethoxysilane was added, the rotation speed was adjusted to 260 rpm, and the primer coating was prepared after aging for 4 hours. In the reaction bottle, 48.2 g of the basic siloxane silica sol, 2.1 g of 50% concentration formic acid were added, mixed and stirred, the pH was measured to be 3.6, and then 18.2 g of methyltrimethoxysilane, 1.4 g of polydimethylsiloxane, and 3.6 g of hydroxyl silicone oil (with the structural formula HO[-Si(CH3)2-O-] nCH3, n=40-70, molecular weight 3000-5000) was added, the rotation speed was adjusted to 260 rpm, and the primer coating was prepared after maturation for 3 hours. After the aluminum plate was sandblasted and cleaned, it was preheated to 50°C. The already matured primer coating and the top coating were filtered through a 400-mesh filter and poured into the spray gun tank. The primer coating was uniformly sprayed on the substrate for 3 layers, and then 1 layer of the top coating was sprayed wet. The coating was placed in a 150°C oven for 5 minutes of surface drying, and then moved to a 260°C oven for high-temperature sintering for 10 minutes, thereby obtaining a high-wear-resistant inorganic non-stick coating with excellent performance.

[0077] Comparative Example 6

[0078] The difference from Example 2 is only that the maturation time of the primer is reduced from 4 hours to 3 hours, and the maturation time of the top coating is reduced from 4 hours to 3 hours. The remaining steps and materials and compositions are consistent with Example 2, which specifically includes:

[0079] In a reaction bottle, 54.6 g of the silica sol color paste prepared in Example 1 and 3 g of a 25% concentration formic acid solution were mixed and stirred. The pH was tested to be 3.62. Then, 1.8 g of polydimethylsiloxane, 4.2 g of KH-560, and 2.8 g of methyl silicone oil (with the structural formula CH3[-Si(CH3)2-O-] n In a reaction bottle, 54.6 g of the silica sol color paste prepared in Example 1 and 3 g of a 25% concentration formic acid solution were mixed and stirred. The pH was tested to be 3.62. Then, 1.8 g of polydimethylsiloxane, 4.2 g of KH-560, and 2.8 g of methyl silicone oil (with the structural formula CH3[-Si(CH3)2-O-] n In a reaction bottle, 54.6 g of the silica sol color paste prepared in Example 1 and 3 g of a 25% concentration formic acid solution were mixed and stirred. The pH was tested to be 3.62. Then, 1.8 g of polydimethylsiloxane, 4.2 g of KH-560, and 2.8 g of methyl silicone oil (with the structural formula CH3[-Si(CH3)2-O-]

[0080] Performance Test

[0081] The high wear-resistant post-non-stick coating based on silica sol and silicone prepared in Example 2-3 and the coating prepared in Comparative Example 3-6 were respectively tested for hardness, adhesion, wear resistance, post-wear non-stickness and other properties. The hardness test was carried out according to GB / T 6739, and the results were evaluated as follows: paint film scratch; the adhesion test was carried out according to GB / T 9286, with a spacing of 2 mm; the wear resistance test was carried out according to GB / T 1768-2006. Wet grinding was carried out with a wear tester pressing against the scouring pad until the appearance of a scratch revealing the bottom, and the number of times was recorded. The post-wear non-stickness test was carried out according to GB / T 1768-2006. After 1000 times of grinding, the oil-free fried egg test was carried out, and the egg could be taken out completely to pass, and the number of times was recorded.

[0082] Table 1: Test results of product performance of Example 2-3 and Comparative Example 3-6:

[0083] Case Hardness Adhesion Wear resistance Non-stick after wear Example 2 9H 0 level 120000 times 2000 times Comparative Example 3 9H 0 level 17000 times 0 times Comparative Example 4 9H 1 level 94000 times 1000 times Example 3 9H 0 level 120000 times 17000 times Comparative Example 5 8H 0 level 8000 times 0 times Comparative Example 6 7H 2 level 3000 times 0 times

[0084] From the comparison of the above table data:

[0085] Comparative Example 3 used the silica sol color paste prepared by Comparative Example 1 without wear-resistant filler (silicon carbide). Due to the lack of wear-resistant filler protection in the system, the coating was easily damaged after multiple abrasions and thus leaked out of the substrate, indicating that the addition of an appropriate amount of wear-resistant filler in the coating can efficiently improve the wear resistance of the coating.

[0086] Comparative Example 4 used the silica sol color paste prepared by Comparative Example 2 with a high amount of wear-resistant filler. Due to the increase in wear-resistant filler, the amount of whisker silicon and color powder needs to be reduced accordingly. Too little color powder can lead to ineffective hiding of the substrate, affecting the appearance, so the proportion of whisker silicon is reduced. As shown by the test, the lack of whisker-like structures that penetrate the coating in the coating leads to a porcelain collapse phenomenon when encountering scratches.

[0087] Example 3 used small molecular weight hydroxyl-terminated methyl silicone oil to replace ordinary methyl silicone oil. This will make the silicone oil no longer physically fixed on the surface of the coating, but will condense with the network of the coating and be bonded to the coating. This can effectively improve the long-acting non-stick performance of the coating.

[0088] Comparative Example 5 extended the curing time of the coating. As shown by the test results, the hardness and wear resistance of the coating decreased significantly after over-curing, and some small particles appeared on the surface of the coating. These are all due to over-curing of the coating, which has been preliminarily agglomerated in the reaction bottle.

[0089] Comparative Example 6 shortened the curing time of the coating. As shown by the test results, the hardness, adhesion, and wear resistance of the coating decreased significantly due to insufficient curing. This may be due to insufficient hydrolysis of silicone in the coating and insufficient condensation between silicon hydroxyl groups, resulting in a loose network structure after film formation.

[0090] The raw materials and equipment used in the present application are conventional raw materials and equipment in the art unless otherwise specified; the methods used in the present application are conventional methods in the art unless otherwise specified.

[0091] The above description is only the preferred embodiment of the present application, and does not limit the present application in any way. Any simple modification, change and equivalent transformation of the above embodiment according to the technical essence of the present application still falls within the protection scope of the technical solution of the present application.

Claims

1. A method for preparing a high wear-resistant inorganic non-stick coating, characterized in that... include: 1) Preparation of primer coating: Mix 50-75 parts of silica sol color paste with 1-3 parts of acid catalyst, add 1-2 parts of leveling agent, 3-7 parts of silane coupling agent, 2-5 parts of low molecular weight hydroxyl-terminated methyl silicone oil with molecular weight of 300-2000 and 10-20 parts of siloxane, stir and mature at 240-260 rpm for 4 hours to obtain primer coating; The silica sol color paste includes: 40-70 parts of alkaline silica sol with a solid content of 30-35 wt%, 10-15 parts of inorganic color powder, 10-20 parts of anti-chipping filler, and 1-5 parts of wear-resistant filler; The anti-chipping filler is selected from whisker silicon, whisker alumina and whisker silicon nitride; the wear-resistant filler is selected from silicon carbide and corundum. 2) Preparation of topcoat: Mix 45-70 parts of alkaline silica sol with 1-3 parts of acid catalyst, add 13-21 parts of siloxane, 1-2 parts of leveling agent, and 2-5 parts of low molecular weight hydroxyl-terminated methyl silicone oil with a molecular weight of 300-2000, stir and mature at 240-260 rpm for 4 hours to obtain topcoat. The above ingredients are listed in parts by weight.

2. The preparation method according to claim 1, characterized in that: In the primer coating: The siloxane is selected from methyltrimethoxysilane, ethyltrimethoxysilane and phenyltrimethoxysilane; The acid catalyst is selected from formic acid solution, acetic acid solution and hydrochloric acid solution; The leveling agent is selected from polydimethylsiloxane and polymethylphenylsiloxane; The silane coupling agent is selected from KH-550, KH-560 and KH-570.

3. The preparation method according to claim 1, characterized in that: In the topcoat coating: The siloxane is selected from methyltrimethoxysilane, ethyltrimethoxysilane and phenyltrimethoxysilane; The acid catalyst is selected from formic acid solution, acetic acid solution and hydrochloric acid solution; The leveling agent is selected from polydimethylsiloxane and polymethylphenylsiloxane.

4. The preparation method according to claim 1, characterized in that: In step 1), the preparation method of the silica sol color paste includes: mixing and ball milling alkaline silica sol, inorganic color powder, anti-chipping filler and wear-resistant filler to obtain silica sol color paste.

5. The application of the high wear-resistant inorganic non-stick coating obtained by the preparation method according to any one of claims 1-4 in the preparation of non-stick coatings for cookware, characterized in that... include: After sandblasting and cleaning the cookware substrate, it is preheated, then sprayed with at least two layers of primer, followed by at least one layer of topcoat, dried, and sintered to obtain a highly wear-resistant inorganic non-stick coating.

6. The application according to claim 5, characterized in that: The primer coating is applied in 2-3 layers, and the topcoat coating is applied in 1-2 wet spray layers.

7. The application according to claim 5, characterized in that: The preheating temperature is 40-60℃.

8. The application according to claim 5, characterized in that: The primer and topcoat are pre-filtered through a 300-500 mesh screen.

9. The application according to claim 5, characterized in that: The drying temperature is 140-160℃, and the time is 3-10 minutes.

10. The application according to claim 5, characterized in that: The sintering temperature is 240-280℃ and the time is 5-20min.