Slow-release particles and preparation method, and ceramic coating material and its preparation method

Abstract

Slow-release particles and its preparation method, and a ceramic coating material and its preparation method, are provided The slow-release particles comprise: a slow-release material having a porous structure and / or layered structure; silicone oil, binding to the slow-release material. The slow-release material comprises at least one of vermiculite, zeolite, bentonite, diatomaceous earth, alpha alumina, silica aerogel, fumed silica, amorphous silica, hollow glass micropowder, porous silicate, layered silicate, porous phosphate, layered phosphate, porous carbonate, layered carbonate, porous sulfate and layered sulfate.

Description

[0001] Slow-release Particles and Preparation Method, and Ceramic Coating Material and Its Preparation Method

[0002] Field of the Invention

[0003] The present invention belongs to the technical field of non-stick coating materials, and in particular, to slow-release particles and its preparation method, as well as a ceramic coating material and its preparation method.

[0004] Background of the Invention

[0005] At present, non-stick technology mainly consists in PTFE coating materials and ceramic coating materials. Compared with PTFE products, the use of ceramic coating materials is very limited due to their short non-stick life span and they cannot meet consumers’ daily usage requirements for non-stick utensils, in particular utensil made of metal. For example, for non-stick pans, stickiness will generally occur after about one month of household use. Especially with the Chinese high-temperature cooking method, and with wear and tear caused by the use of a metal spatula, non-stickiness deteriorates very quickly.

[0006] Therefore, enhancing the durable non-stick performance of ceramic coating materials has become a very meaningful and urgent technical need.

[0007] Summary of the Invention

[0008] In view of the shortcomings of the prior art, the present invention provides slow-release particles and its preparation method, as well as a ceramic coating material and its preparation method.

[0009] According to an aspect of the present invention, the slow-release particles comprises: a slow-release material having a porous structure and / or layered structure; silicone oil, binding to the slow-release material, wherein, the slow-release material includes at least one of vermiculite, zeolite, bentonite, diatomaceous earth, alpha alumina, silica aerogel, fumed silica, amorphous silica, hollow glass micro powder, porous silicate, layered silicate, porous phosphate, layered phosphate, porous carbonate, layered carbonate, porous sulfate and layered sulfate.

[0010] The particle size of the slow-release particles can be smaller than or equal to 20 microns, preferably smaller than or equal to 15 microns.

[0011] By weight percentage, the silicone oil can comprise 20%-30% low molecular weight silicone oil, 40%-60% medium molecular weight silicone oil, and 20%-30% high molecular weight silicone oil. The molecular weight of the low molecular weight silicone oil can be between 500 to 1 ,000, the molecular weight of the medium molecular weight silicone oil can be between 3,000 to 6,000, and the molecular weight of the high molecular weight silicone oil can be between 12,000 to 30,000.

[0012] According to another aspect of the present invention, the use of the above slow-release particles to provide non-stickiness property to a cooking utensil.

[0013] According to another aspect of the present invention, a method of preparing slow-release particles comprises: providing a slow-release material and silicone oil; mixing 35 to 58 parts by weight of the slow-release material with 42 to 60 parts by weight of the silicone oil, so that the silicone oil is bound to the slow-release particle, so as to obtain the slow-release particle. First, as known in prior art, the slow-release material comprising a porous or layered structure may absorb silicone oil into its open porosity. In addition to this, the silicone oil can be bound to the slow-release material in at least two ways: adsorption and bonding. It should be understood that adsorption refers to the attachment of the silicone oil onto the surface of the slow-release material, which may be physical or chemical adsorption but the interactions between adsorbent (slow-release material having porous structure) and adsorbate (silicon oil) are often weak. On the other hand, bonding refers to a stronger chemical bond achieved through interactions of atoms. In the present invention, for example, it may refer to the condensation of the hydroxyl groups of the silicone oil and the hydroxyl groups of the slow-release material.

[0014] According to the present invention, in the mixing step, the silicone oil, the slow-release material, and a coupling agent can be mixed evenly and ground to a particle size of smaller than or equal to 30 microns, at which moment, some of the silicone oil can be adsorbed on the slow-release material. Then, a catalyst is added to the mixture, the grinding continues until the particle size is smaller than or equal to 20 microns. Then, ultrasonic treatment is performed for 0.5 h to 1 h so that more silicone oil is bound to the slow-release material by bonding. Finally, the silicone oil can be dried to a semi-solid state by heating and solidifying and bound to the slow-release material in a colloidal form to obtain the slow-release particle. The particle size of the slow-release material is, for example, 100 mesh to 3,000 mesh. Besides ultrasonic treatment, other methods known to those skilled in the art can also be used to achieve the bonding between the silicone oil and the slow-release material, such as heating and pressurizing, and / or the use of acidic / basic salts, etc.

[0015] According to another aspect of the present invention, a ceramic coating material comprises a ceramic coating material precursor and slow-release particles dispersed in the ceramic coating material precursor. 5.15-32.97 parts by weight of the slow-release particles can be comprised in every 100 parts by weight of the ceramic coating material.

[0016] According to another aspect of the present invention, a ceramic coating made of the above-described ceramic coating material can comprise a single layer, and the thickness of the single layer ranges from 10 microns to 80 microns.

[0017] The ceramic coating can also comprise at least two sub-layers, and at least the uppermost sub-layer of the at least two sub-layers comprises slow-release particles. Preferably, the thickness of each sub-layer is not less than 10 microns, and the sum of the thickness of each sub-layer is not more than 80 microns.

[0018] Optionally, the content of the slow-release particles comprised in each sub-layer is different from each other. Preferably, the ceramic coating is applied on a substrate, and the content of the slow-release particles in each sub-layer increases in a direction away from the substrate.

[0019] Preferably, the content of the slow-release particles comprised in the first sub-layer is such that 0 to less than 32.97 parts by weight of the slow-release particles are comprised in every 100 parts by weight of the first sub-layer, and the content of the slow-release particles comprised in the second sub-layer is such that 5.15 to 32.97 parts by weight of the slow-release particles are comprised in every 100 parts by weight of the second sub-layer.

[0020] Optionally, the particle size of the slow-release particles comprised in each sub-layer in the ceramic coating is different from each other.

[0021] The ceramic coating can further comprise a third sub-layer arranged between the first sub-layer and the second sub-layer. The content of the slow-release particles comprised in the ceramic coating material of the third sub-layer can be different than the content of the slow-release particles comprised in each of the first sub-layer and the second sub-layer.

[0022] According to another aspect of the present invention, a stacked ceramic coating comprises the above-described ceramic coating as a first ceramic coating, and further comprises a second ceramic coating located on the first ceramic coating as a sealing layer and formed by a second ceramic coating material. By providing the second ceramic coating formed by means of a conventional (i.e., not comprising slow-release particles) ceramic material as a sealing layer, the release of the silicone oil is further slowed, so as to maintain the durable non-stickiness of the ceramic coating. The second ceramic coating has a thickness of, for example, 8 to 20 microns. Preferably, the ceramic coating material precursor comprises the same material as the second ceramic coating material.

[0023] Another aspect of the present invention further relates to a non-stick utensil comprising: a substrate, a surface of which has a surface roughness of 3 microns to 15 microns; the above-described ceramic coating or stacked ceramic coating, located on the surface of the substrate.

[0024] The substrate comprises, for example, two or more layers constituted by at least two materials selected among aluminum, aluminum alloys, titanium, titanium alloys, iron, and stainless steel.

[0025] The substrate can also comprise a base layer and a functional layer arranged between the base layer and the ceramic coating or the stacked ceramic coating, and a surface of the functional layer has a surface roughness of 3 microns to 15 microns.

[0026] According to another aspect of the present invention, a method of preparing a ceramic coating material comprises: preparing a ceramic coating material precursor; preparing slow-release particles by means of the above-described method; and, mixing the ceramic coating material precursor with the slow-release particles, so as to obtain the ceramic coating material.

[0027] The step of preparing the ceramic coating material precursor can comprise:

[0028] S1 : preparing a material A, a material B, and a material C, wherein: the material A comprises silane; the material B comprises silica sol and a filler as essential components, and optionally, a pigment, a wetting agent, a thickener and an emulsifier as non-essential components, and a solvent; the material C comprises an organic acid as an essential component, and optionally, a pH buffer and a catalyst as non-essential components;

[0029] S2: mixing the material B and the material C, and adjusting the pH of the mixture to lower than or equal to 4, thereby obtaining a first material; and

[0030] S3: mixing the material A with the first material, thereby obtaining a ceramic coating material precursor.

[0031] According to another aspect of the present invention, a method of preparing a ceramic coating material comprises: S1 : preparing a material A, a material B, and a material C, wherein: the material A comprises silane; the material B comprises silica sol and a filler as essential components, and optionally, a pigment, a wetting agent, a thickener and an emulsifier as non-essential components, and a solvent; the material C comprises an organic acid as an essential component, and optionally, a pH buffer and a catalyst as non-essential components; the slow-release particles are prepared by means of the above-described method;

[0032] S2: mixing the material B and the material C, and adjusting the pH of the mixture to lower than or equal to 4, thereby obtaining a first material; and

[0033] S3: mixing the material A and the slow-release particles with the first material, so as to obtain a ceramic coating.

[0034] The silane can comprise at least one of methyltrimethoxysilane, methyltriethoxysilane and dimethyldimethoxysilane, and the material A comprises ethyl orthosilicate; wherein, the material A comprises 80-97 wt.% of the silane, and 3-20 wt.% of the ethyl orthosilicate.

[0035] Another aspect of the present invention further relates to a method of preparing a ceramic coating comprising:

[0036] - preparing a ceramic coating material by means of the above-described method; and

[0037] - forming a ceramic coating on a substrate by the ceramic coating material by means of a layer forming process.

[0038] Preferably, the ceramic coating comprises a first sub-layer arranged on a substrate and a second sub-layer, and the method of preparing a ceramic coating further comprises: preparing a ceramic coating material comprising: a first ceramic coating material 01 comprising a ceramic coating material precursor and optionally the slow-release particles; and, a first ceramic coating material 02 comprising a ceramic coating material precursor and the slow-release particles; and forming a first sub-layer on the base material by the first ceramic coating material 01 by means of a layer forming process, and forming a second sub-layer on the first sub-layer by the first ceramic coating material 02, the content of the slow-release particles comprised in the first sub-layer being different from the content of the slow-release particles comprised in the second sub-layer.

[0039] Preferably, the content of the slow-release particles comprised in the first sub-layer is lower than the content of the slow-release particles comprised in the second sub-layer.

[0040] Preferably, the ceramic coating further comprises a third sub-layer arranged between the first sub-layer and the second sub-layer, the ceramic coating material further comprises a third ceramic coating material comprising a ceramic coating material precursor and slow-release particles, and the method further comprises forming the third sub-layer on the first sub-layer by the third ceramic coating material, and then forming the second sub-layer on the third sub-layer, wherein, the content of the slow-release particles comprised in the third sub-layer is different from the content of the slow-release particles comprised in each of the first sub-layer and the second sub-layer.

[0041] The present invention discloses adding slow-release particles, which comprises slow-release material, into a ceramic coating material. The slow-release material has a disordered porous and / or layered structure. In this case, silicone oil can be bound to the slow-release material. Therefore, during cooking, due to the porous and / or layered structure of the slow-release material, the release of the silicone oil can be slowed, and thus a durable non-stickiness can be maintained. In addition, by forming a ceramic coating comprising a gradient in the content of the slow-release particle, the combination between the ceramic coating and a substrate material can be enhanced while ensuring an excellent non-stickiness performance, so as to increase the life span of the ceramic coating.

[0042] Description of the Drawings

[0043] Fig. 1 is a schematic view that shows a ceramic coating material according to the present invention;

[0044] Fig. 2 is a schematic view that shows slow-release particles in a ceramic coating material according to the present invention;

[0045] Fig. 3 is a schematic view of a first embodiment of a ceramic coating according to the present invention;

[0046] Fig. 4 is a schematic view of a second embodiment of a ceramic coating according to the present invention;

[0047] Fig. 5 is a schematic view of a third embodiment of a ceramic coating according to the present invention;

[0048] Fig. 6 is a schematic view of a fourth embodiment of a ceramic coating according to the present invention; and Fig. 7 is a schematic view of a fifth embodiment of a ceramic coating according to the present invention.

[0049] Detailed Description of the Invention

[0050] The present invention will now be more fully described below with reference to the accompanying drawings, in which embodiments are shown. The present invention can, however, be embodied in many different forms and should not be construed as limited to the embodiments set forth herein. Rather, these embodiments are provided so that the present disclosure will be thorough and complete, and will fully convey the scope of the present invention to those skilled in the art. The same references always refer to the same elements.

[0051] A ceramic coating material achieves non-stickiness mainly by relying on the silicon methyl groups and doped silicone oil in the ceramic coating material. As the product is heated and worn during use, the silicone oil in a coating will gradually be lost, destroying the silicone methyl groups on the surface, and thus the non-stickiness will be lost. Finally, sticking of cooking pans will occur. If continuous retention of oil can be achieved in a ceramic coating, durable non-stickiness can be achieved by forming an effective oil film that separates food from the coated surface.

[0052] Therefore, the present invention provides a ceramic coating material comprising slow-release particles containing slow-release material which has a disordered porous and / or layered structure, so that the silicone oil can be bound to the slow-release material (by absorption and bonding). During cooking for example, the release of the silicone oil is slowed, thereby maintaining durable non-stickiness. However, there is no limit to the utilization scenarios of the ceramic coating material and the slow-released particles comprised in it. In other words, those skilled in the art can, based on the prior art, apply the ceramic coating material and the slow-release particles comprised in it to any environment that needs slow release of a non-stick material (such as non-stick coating of cooking utensils (for example, woks and inner pots for electric rice cooker), inner and outer coatings of transportation pipelines, etc.).

[0053] Fig. 1 is a schematic view that shows a ceramic coating material according to the present invention. Fig. 2 is a schematic view of slow-release particles in a ceramic coating material according to the present invention. Below, exemplary embodiments of the present invention are described in reference to Figs. 1 and 2.

[0054] As shown in Fig. 1 , the ceramic coating material according to the present invention can comprise a ceramic coating material precursor 1 and slow-release particles 2 dispersed in the ceramic coating material precursor 1 The ceramic coating material precursor 1 can be equivalent to a ceramic coating material used in the art, and therefore can have components of ceramic coating materials commonly used in the art and thus can be realized using methods of preparing a ceramic coating material known in the art. However, the present invention is not limited thereto. As mentioned in the method of preparing the ceramic coating material precursor 1 according to the present invention described below in conjunction with exemplary embodiments, the ceramic coating material precursor 1 can be prepared by the method described below, and the ceramic coating material precursor 1 prepared by using the method of the invention to be described below provides even better compatibility with the slow-release particles to improve the non-stickiness.

[0055] The slow-release particles 2 dispersed in the ceramic coating material precursor 1 comprise a slow-release material 21 and silicone oil 22 bound to the slow-release material.

[0056] According to an exemplary embodiment, the slow-release material 21 can have a layered and / or porous structure. Thus, the silicone oil 22 can be bonded to a surface of the slow-release material and / or absorbed in the porous and / or layered structure. According to an example, the slow-release material 21 can comprise at least one of vermiculite, zeolite, bentonite, diatomaceous earth, alpha alumina, silica aerogel, fumed silica, amorphous silica, hollow glass powder, porous silicate, layered silicate, porous phosphates, layered phosphates, porous carbonates, layered carbonates, porous sulfates and layered sulfates. The slow-release material 21 has a porous and / or layered structure and is bound to the silicone oil. Thus, during use of a cooking utensil that has a non-stick coating formed by a ceramic coating material according to the present invention, the silicone oil 22 bound to the slow-release material 21 can be released slowly, thereby greatly enhancing the durable non-stickiness of the non-stick coating formed by the ceramic coating material.

[0057] By means of a porous structure, it should be understood according to the invention, a structure having open porosity. It means a structure having open pores, some of the open pores being interconnected and forming a network passing through from one face to the other of said structure.

[0058] Thus, the porous structure has a volume of air voids also called open pores incorporated in the thickness of the structure in order to absorb the silicon oil deposited on the porous structure. These air voids or open pores come from spaces left free in the material of the structure during its formation. Air voids or open pores tend to be interconnected, and thus can form a through-pore network of porosity, that could be filled by the silicon oil by absorption. Therefor the silicon oil is stacked in the porous structure. The silicon absorption by the porous structure is either physical or chemical process in which atoms, molecules or ions enter the solid phase of the porous structure. The absorbed silicon oil, for their part, enter inside the phase (i.e. deep in the volume).

[0059] It should also be possible that the porous structure is able to bind the silicon oil by means of adsorption, meaning that the porous structure (adsorbent) can fix the silicon oil (adsorbate) on its surface. The interactions between adsorbent and adsorbate are most often electrostatic in nature, therefore weak and reversible.

[0060] By the term “binding” according to the invention, it should be understood either a non-polar covalent bond, a polar covalent bond, an ionic bond, a hydrogen bond, an electrostatic bond or any weak binding.

[0061] According to an exemplary embodiment, the silicone oil 22 is bound to the slow-release material 21 and provides the main non-stickiness of the ceramic coating material. Here, the silicone oil 22 can be selected from at least one of methyl silicone oil, dimethyl silicone oil, hydroxyl silicone oil, hydro silicone oil and polyether modified silicone oil. In addition, by weight percentage, the silicone oil 22 can comprise 20%-30% low molecular weight silicone oil, 40%-60% medium molecular weight silicone oil, and 20%-30% high molecular weight silicone oil, with the molecular weight of the low molecular weight silicone oil between 500-1 ,000, the molecular weight of medium molecular weight silicone oil between 3,000-6,000, and the molecular weight of the high molecular weight silicone oil between 12,000-30,000. Here, the silicone oil 22 can be prepared by mixing different molecular weights. High molecular weight silicone oil bonds more strongly with the slow-release material and has a slower release rate; small molecular weight silicone oil has a better free mobility and thus better non-stickiness; in addition, medium molecular weight silicone oil has both a free mobility and a strong bonding. Therefore, by combining low molecular weight silicone oil, medium molecular weight silicone oil, and high molecular weight silicone oil, slow release and non-stickiness can be better achieved.

[0062] In addition, in order to improve the strength of the binding between the silicone oil and the slow-release material, there can also be a coupling agent between the slow-release material and the silicone oil. Here, the coupling agent can comprise a silane coupling agent. However, exemplary embodiments are not limited thereto, and the coupling agent can be omitted.

[0063] Preferably, the particle size of the slow-release particles according to an exemplary embodiment can be smaller than or equal to 20 microns, preferably smaller than or equal to 15 microns, and the particle size of the slow-release particles can follow a normal distribution. This is because an excessively large particle size (for example, greater than 20 microns) tends to have a great impact on the appearance of the formed non-stick coating.

[0064] According to an exemplary embodiment, in every 100 parts by weight of the ceramic coating material, there can be 5.15 to 32.97 parts by weight of the slow-release particles. When there is too much of the ceramic coating material precursor, the content of the slow-release particles is relatively small, and thus the slow-release effect is not good. However, when the content of the slow-release particles is relatively high, the strength and bonding force of the coating will be reduced.

[0065] In reference to Fig. 3, a ceramic coating 200 according to a first exemplary embodiment of the present invention is applied on a substrate 100. The ceramic coating 200 is formed using a ceramic coating material comprising a ceramic coating material precursor 1 and slow-release particles 2 dispersed in the ceramic coating material precursor. According to an exemplary embodiment, the substrate 100 can be a substrate known in the art for making a cooking utensil and can comprise a stainless-steel substrate, an iron substrate, an aluminum substrate, a titanium substrate, etc.

[0066] Fig. 3 shows a single-layer ceramic coating 200 applied on the substrate 100. However, embodiments are not limited thereto. As shown in Figs. 4 to 6, the ceramic coating can also comprise at least two (e.g., two, three, etc.) layers of ceramic coating.

[0067] In addition, when the ceramic coating 200 is a single layer, the single-layer ceramic coating 200 can have a thickness in the range of 10 microns to 80 microns. When the thickness of the ceramic coating 200 is less than 10 microns, the ceramic coating has an insufficient wear resistance and can easily be worn and leak; to the contrary, when the thickness of the ceramic coating is greater than 80 microns, the coating will become loose, thereby reducing its impact resistance.

[0068] Above, the case where the ceramic coating 200 is a single layer is described with reference to Fig. 3. Below, the case where the ceramic coating 200 comprises a plurality of sub-layers will be described with reference to Figs. 4 to 6 .

[0069] Fig. 4 is a schematic view that shows a second embodiment of a ceramic coating according to an exemplary embodiment; Fig. 5 is a schematic view that shows a third embodiment of a ceramic coating according to an exemplary embodiment; Fig. 6 is a schematic view that shows a fourth embodiment of a ceramic coating according to an exemplary embodiment. In Figs. 4 to 6, the ceramic coating 200 comprises a first sub-layer 201 and a second sub-layer 202. The content and size of the slow-release particles in Figs. 4, 5 and 6 are different. In reference to Fig. 4, a ceramic coating 200 according to a second exemplary embodiment of the present invention can comprise a first sub-layer 201 and a second sub-layer 202. Here, the first sub-layer 201 and the second sub-layer 202 can have the same structure as the ceramic coating 200 described in reference to Fig. 1 . That is, each of the first sub-layer 201 and the second sub-layer 202 comprises a matrix containing a ceramic material and slow-release particles dispersed in the matrix, and the size of the slow-release particles comprised in each sub-layer are identical or not much different. In addition, each of the first sub-layer 201 and the second sub-layer 202 can have a thickness of not less than 10 microns, without any specific limitation on the difference in thickness between the first sub-layer and the second sub-layer. For example, the first sub-layer 201 can have a thickness of 20 microns, while the second sub-layer can have a thickness of 30 microns, 40 microns, or 50 microns. In addition, when a plurality (for example, three, four, etc.) of sub-layers are arranged, the sum of the thickness of the plurality of sub-layers can be less than or equal to 80 microns.

[0070] In an exemplary embodiment, the content of the slow-release particles (i.e., the number of the slow-release particles comprised in a unit weight of a sub-layer, for example, the density of the slow-release particles in the sub-layer) in the first sub-layer 201 and the second sub-layer 202 can be different. Preferably, the content of the slow-release particles in the first sub-layer 201 is lower than the content of the slow-release particles in the second sub-layer 201. In other words, when a plurality (for example, two, three, or four) of sub-layers are arranged, the content of the slow-release particles in each sub-layer can increase in the direction away from the substrate 100. In addition, while Fig.4 shows that the content of the slow-release particles in the first sub-layer 201 can be lower than the content of the slow-release particles in the second sub-layer 202, embodiments are not limited thereto. In another exemplary embodiment, the first sub-layer can comprise very few of the slow-release particles or not comprise the slow-release particle at all.

[0071] In addition, when the ceramic coating comprises a plurality (for example, two or three) of sub-layers, the content of the slow-released particles comprised in at least the uppermost sub-layer can be such that 5.15 to 32.97 parts by weight of the slow-released particles are dispersed in every 100 parts by weight of the sub-layer, and there is no specific limitation on the content of the slow-release particles comprised in sub-layers located below.

[0072] For example, when the ceramic coating comprises two sub-layers, the content of the slow-release particles in the lowermost sub-layer 201 can be such that 3 parts by weight of the slow-release particles are dispersed in every 100 parts by weight of the sub-layer 201 , while the content of the slow-release particles in the uppermost sub-layer 202 can be such that 30 parts by weight of the slow-release particles are dispersed in every 100 parts by weight of the sub-layer 202. As another example, when the ceramic coating comprises three sub-layers, the content of the slow-release particles in the uppermost sub-layer can be such that 2 parts by weight of the slow-release particles are dispersed in every 100 parts by weight of the sub-layer 201 , the content of the slow-release particles in the middle sub-layer can be such that 3 parts by weight of the slow-release particles are dispersed in every 100 parts by weight of the sub-layer 201 , and the content of the slow-release particles in the uppermost sub-layer can be such that 25 parts by weight of the slow-release particles are dispersed in every 100 parts by weight of the sub-layer.

[0073] In other words, when a plurality of sub-layers are arranged, the content of the slow-release particles comprised in each sub-layer can gradually increase (for example, with a gradient) in the direction away from the substrate 100 and the content of the slow-release particles comprised in the uppermost sub-layer (for example, 202) is such that 5.15 to 32.97 parts by weight of the slow-release particles are dispersed in every 100 parts by weight of the sub-layer. Alternatively, the sub-layer(s) arranged below the uppermost sub-layer (for example, 202) have the same or different content(s) of the slow-release particles lower than that of the uppermost sub-layer which is such that 5.15 to 32.97 parts by weight of the slow-release particles are dispersed in every 100 parts by weight of the sub-layer. In other words, the content of the slow-release particles in the sub-layer(s) arranged below the uppermost sub-layer is limited be lower than the content of the slow-release particles in the uppermost sub-layer, which is within the range of 5.15 to 32.97 parts by weight of the slow-release particle dispersed in every 100 parts by weight of the corresponding sub-layer(s).

[0074] In reference to Fig. 5, the ceramic coating according to a third embodiment differs from the ceramic coating of the second embodiment of Fig. 4 only in that the size of the slow-release particles comprised in the first sub-layer 201 is different from the size of the slow-release particles comprised in the second sub-layer. For example, as shown in Fig. 5, the size of the slow-release particles comprised in the first sub-layer 201 is smaller than the size of the slow-release particles comprised in the second sub-layer 202. For example, the size of the slow-release particles comprised in the first sub-layer 201 can be smaller than or equal to 11 microns and follows a normal distribution, while the size of the slow-release particles comprised in the second sub-layer 202 can be smaller than or equal to 15 microns and follows a normal distribution. Here, the sizes of almost all (most of) the slow-release particles comprised in the various sub-layers can all be no larger than 20 microns, and the slow-release particles comprised in the uppermost sub-layer (for example, 202) can have an optimal particle size.

[0075] In reference to Fig. 6, the ceramic coating according to a fourth embodiment differs from the ceramic coating of the third embodiment of Fig. 5 only in that the contents of the slow-release particles comprised in the various sub-layers are identical. In other words, the content of the slow-release particles in the first sub-layer 201 in the fourth embodiment of Fig. 6 is identical to the content of the slow-release particles in the second sub-layer 202, but the size of the slow-release particles in the first sub-layer 201 is smaller than the size of the slow-release particles in the second sub-layer 202.

[0076] Fig. 7 shows a single layer of first ceramic coating 200 applied on the substrate 100. However, exemplary embodiments are not limited thereto. In other words, the first ceramic coating 200 can also comprise at least two (for example, two, three, etc.) sub-layers of the ceramic coatings as described above.

[0077] When the first ceramic coating 200 is single-layer, the single-layer ceramic coating 200 can have a thickness within the range of 10 microns to 80 microns. When the first ceramic coating 200 comprises at least two sub-layers, the at least two sub-layers can be identical except for the content and particle size of the slow-release particle.

[0078] The second ceramic coating 300 is located above the first ceramic coating 200. The second ceramic coating 300 can be formed using a second ceramic coating material. Here, the second ceramic coating material can be identical to or different from the ceramic coating material precursor in the first ceramic coating material (for example, can comprise the same or a different material). In other words, the second ceramic coating material can differ from the first ceramic coating material only in that the second ceramic coating material does not comprise the slow-release particles (or further, does not comprise a filler), and the second ceramic coating material can be the ceramic coating material precursor formed during the preparation of the first ceramic coating material that will be described below or obtained by the method of preparing the ceramic coating material precursor. Alternatively, the second ceramic coating material can be a ceramic coating material commonly used in the prior art or prepared using a conventional formula. For example, according to an example, the ceramic coating material can be prepared according to a commonly used formula using a silane, alkaline silica sol and a non-stick additive.

[0079] The second ceramic coating 300 does not comprise the slow-release particles and is used as a sealing layer to further slowdown the release of the silicone oil in the slow-release particles in the first ceramic coating 200. Therefore, the second ceramic coating 300 can have a thickness of 8 microns to 20 microns.

[0080] The ceramic coating material and ceramic coating according to the present invention have been described in detail above in connection with exemplary embodiments. Below, a method of preparing a ceramic coating material will be described in detail. The steps of the method of preparing a ceramic coating material according to the present invention can comprise steps of separately preparing a ceramic coating material precursor and slow-release particles, and mixing the ceramic coating material precursor and the slow-release particles so as to obtain a ceramic coating material. However, exemplary embodiments are not limited thereto. That is, the step of preparing a ceramic coating material precursor can be combined with the step of preparing slow-release particle. Below, a method of preparing a ceramic coating material according to the present invention wherein the ceramic coating material precursor and the slow-release particles are prepared separately is mainly described.

[0081] Preparation of a Ceramic Coating Material Precursor

[0082] According to an exemplary embodiment, the steps of preparing a ceramic coating material can comprise a step of providing materials and a step of mixing. They are described in detail below.

[0083] The step of providing materials can comprise steps of separately providing a material A, a material B, and a material C.

[0084] Here, the material A can comprise a silane. The material B can comprise silica sol and a filler as essential components, optional pigment, wetting agent, thickener, and emulsifier as nonessential components, and a solvent. The material C can comprise an organic acid as an essential component, and optional pH buffer and catalyst (zirconium acetate) as nonessential components.

[0085] In the material A, according to an exemplary embodiment, the silane is used to form polysiloxanes during the formation of a ceramic coating material. Therefore, the silane here can include materials known in the art for condensation to form polysiloxanes. According to an exemplary embodiment, the silane can comprise at least one of methyltrimethoxysilane, methyltriethoxysilane, and dimethyldimethoxysilane, but is not limited thereto. In addition to the silane, the material A can also comprise ethyl orthosilicate that can be condensed to form polysiloxane, and in this case, the material A may comprise 80%-97 wt.% of the silane, and 3%-20 wt.% of the ethyl orthosilicate.

[0086] The material B can necessarily comprise a filler and silica sol. The filler plays a role in increasing the wear resistance of the coating material. The present invention does not limit the type of the filler, and common fillers can be used. For example, at least one of mica powder, kaolin, montmorillonite, silicon carbide, alumina, and silica can be used. In addition, silica sol is a main film-forming substance of a ceramic coating material. It undergoes a sol-gel reaction with polysiloxane under acidic conditions to form a ceramic coating material. Therefore, commerciallv available ordinary silica sol can be selected as the silica sol in the material B of the present invention. For example, the silica sol can be AkzoNobel 1050 (silica sol) or U.S. Grace LUDIXAM-50.

[0087] The essential components in the material B can be dispersed in a solvent. That is to say, the B material can also comprise a solvent. Here, the solvent can comprise deionized water. In order to be able to adjust the volatilization speed of the solvent during the drying process of the coating material, the solvent can also comprise isopropyl alcohol. In addition, the proportional relationship between isopropyl alcohol and water is not limited and, optionally, can be formulated according to actual needs.

[0088] In the material B, in addition to the above-mentioned essential components, one or more of pigments, wetting agents, thickeners, and emulsifiers can also be optionally comprised as unessential components. Here, pigments are mainly used to give different colors to the coating material, and therefore common inorganic pigments can be used. Inorganic pigments have good temperature resistance and safety and should be selected for high temperature resistant areas. According to an exemplary embodiment, at least one of carbon black, copper chrome black, titanium dioxide, and iron oxide can be selected as a filler. In addition, during the preparation of essential components in a solvent, in order to provide excellent properties of the materials, at least one of a wetting agent, a thickener, and an emulsifier can also be added to the materials.

[0089] According to a particular example, the material B can comprise, by weight percentage: 30wt%-48wt% silica sol, 8wt%-13wt% pigment, 8wt%-25wt% filler, 0.2wt%-1wt% wetting agent, 1wt%-3wt% thickener, 3wt%-5wt% emulsifier, and the remainder is isopropyl alcohol and deionized water. However, exemplary embodiments are not limited thereto, and one or more of the non-essential components can be omitted.

[0090] The material C serves as a strongly acidic catalyst and can comprise an organic acid as an essential component, and optional pH buffer and catalyst (e.g., zirconium acetate) as non-essential components. Here, the organic acid is used to adjust the pH value of the silica sol in a subsequent process so that it can react with the material A in an acidic environment. Therefore, organic acids commonly used in the art for ceramic coating materials can be used. According to an exemplary embodiment, at least one of formic acid and acetic acid can be selected as the organic acid. When both formic acid and acetic acid are used, the weight ratio between formic acid and acetic acid can range between 4:6 and 1 :1. In addition, in the material C, a pH buffer and a catalyst can also be optionally comprised. Here, the pH buffer and the catalyst can be those known in the art and used in the process of preparing a strongly acidic catalyst for ceramic coating materials. For example, the pH buffer can be weak acids such as boric acid, and the catalyst is used to accelerate sol-gel reaction speed and can be zirconium acetate. However, exemplary embodiments are not limited in terms of the types of pH buffers and catalysts, and suitable pH buffers and catalysts can be omitted or appropriately selected based on the prior art.

[0091] According to an exemplary embodiment, the material C can comprise 80 to 97 parts by weight of a mixture of formic acid and acetic acid, 1 to 2 parts by weight of a boric acid pH buffer, and 0.5 part by weight of a zirconium acetate catalyst.

[0092] After providing the materials mentioned above, the mixing step can be performed. Herein, the mixing step can comprise a first mixing step of mixing the material B and the material C to obtain a first material and a second step of mixing the product of the first mixing step (i.e. , the first material) with the material A.

[0093] Specifically, 40 to 60 parts by weight of the material B can be mixed with 1 to 2 parts by weight of the material C, thereby adjusting the pH of the mixture to acidity (for example, less than or equal to 4) by means of the acidity of the material C, so as to obtain the first material. Since the material B comprises a solid filler and an optional pigment, before the mixing or during the preparation of the material B, the material B can be added to a grinder and ground for 0.5 h to 2 h, so as to fully disperse it evenly and grind it to a particle size of, for example, smaller than or equal to 15 microns, to obtain a uniformly dispersed slurry.

[0094] After mixing the material B and the material C, the mixture may be rolled and dispersed for a predetermined duration (for example, 0.5 h), so that the first material has a high degree of dispersion.

[0095] After obtaining the first material, the material A can be added to the first material. Here, the weight ratio of the added amounts between the material A and the material B can be in the range of (20 to 30): (40 to 60). After adding the material A, shaking can be continued to make it uniform, so that material A and the material B undergo a sol-gel reaction in an acidic environment to form a ceramic coating material precursor.

[0096] Preparation of the Slow-release Particle

[0097] The slow-release particles can be prepared during, before, or after the preparation of the ceramic coating material. The slow-release particles can be prepared by mixing a slow-release material with a silicone oil.

[0098] According to an exemplary embodiment, the slow-release particles can comprise a slow-release material 21 having a porous and / or layered structure described above in reference to Figs. 1 and 2, and a silicone oil 22 bound to the slow-release material. A slow-release material precursor of an appropriate size (i.e., a slow-release material before grinding; when the grinding step is omitted, the slow-release material precursor can be considered as the ultimately used slow-release material) can be selected to prepare the slow-release particles. According to an exemplary embodiment, the slow-release material precursor can have a layered and / or porous structure. According to an example, the slow-release material precursor can comprise at least one of vermiculite, zeolite, bentonite, diatomaceous earth, alpha alumina, silica aerogel, fumed silica, amorphous silica, hollow glass micropowder, porous silicate, layered silicate, porous phosphate, layered phosphate, porous carbonate, layered carbonate, porous sulfate and layered sulfate. The slow-release material precursor has a porous and / or layered structure and is ground to form a slow-release material, which is bound with a silicone oil. The silicone oil bound to the slow-release material can be released slowly during the use of a utensil having a non-stick coating formed by a ceramic coating material according to the present invention, thereby greatly improving the durable non-stickiness of the non-stick coating formed by the ceramic coating material.

[0099] According to an exemplary embodiment, the particle size of the slow-release material precursor can be in the range of 100 mesh to 3,000 mesh, and the particle size of the slow-release material precursor within this range can follow a normal distribution. When the particle size is too large (for example, less than 100 mesh), the particle size may increase the grinding process or make the ground particle size of the slow-release material still too large, ultimately affecting the appearance of a non-stick coating made with the ceramic coating material. On the other hand, a particle size that is too small (for example, larger than 3,000 mesh; in addition, the particle size will become smaller after grinding) makes it difficult to effectively absorb the silicone oil and thus difficult to achieve a good effect of slowly releasing the silicone oil.

[0100] When the slow-release material precursor has the above-mentioned particle size distribution, a two-pass grinding process as will be described below can be used to make the particle size of the ultimately obtained slow-release material below 20 microns. However, exemplary embodiments are not limited thereto. That is, when the slow-release material precursor is selected to have a relatively small value in the range of 100 mesh to 3,000 mesh, one pass of the grinding process can be omitted. Furthermore, when the particle size of the slow-release material precursor is selected to have a still smaller value in the above-mentioned range, the entire grinding process can be omitted. When at least one pass of the grinding processes is omitted, the omitted grinding process can be replaced by a stirring process, or there can be no treatment performed on the mixture.

[0101] The silicone oil can be selected from at least one of methyl silicone oil, dimethyl silicone oil, hydroxyl silicone oil, hydrogen-containing silicone oil, and polyether modified silicone oil. In addition, silicone oils of different molecular weights can be mixed in a certain proportion to form a silicone oil mixture with a normal distribution of molecular weight. For example, by weight percentage, the content of low molecular weight silicone oil can be 20wt%-30wt%, the content of medium molecular weight silicone oil can be 40wt%-60wt%, and the content of high molecular weight silicone oil can be 20wt%-30wt%. Here, the molecular weight of low molecular weight silicone oil can be between 500 and 1 ,000, the molecular weight of medium molecular weight silicone oil can be between 3,000 and 6,000, and the molecular weight of high molecular weight silicone oil can be between 12,000 and 30,000. By using a normally distributed silicone oil composition, slow release and non-stickiness can be better achieved. In fact, high molecular weight silicone oil may be more strongly bound with the slow-release material and is released slower; while low molecular weight silicone oil has better free movement and thus provides better non-stickiness. Medium molecular weight silicone oil allows free movement and combining strength at the same time. Therefore, low molecular weight silicone oil, medium molecular weight silicone oil, and high molecular weight silicone oil can be combined to achieve better slow release and non-stickiness.

[0102] According to an example, 35 to 58 parts by weight of the slow-release material precursor can be mixed with 42 to 60 parts by weight of silicone oil to obtain a mixture, and 1 to 3 parts by weight of a coupling agent (for example, methoxysilane coupling agent), 0.3 part by weight of a catalyst (for example, titanate catalyst), and 1 to 1 .5 parts by weight of a dispersant can be added to the mixture. However, exemplary embodiments are not limited thereto. The coupling agent and catalyst are used to enhance the binding force between the silicone oil and the slow-release material, and the dispersant is used to improve the dispersion of the slow-release material in the silicone oil. However, exemplary embodiments are not limited thereto, and at least one of the coupling agent, the catalyst, and the dispersant can be omitted.

[0103] According to a particular example, silicone oil, a 100 to 3,000 mesh slow-release material precursor, and a silane coupling agent can be mixed evenly and ground until the particle size is less than or equal to 30 microns. At this time, some of the silicone oil is adsorbed by the slow-release material. Then a catalyst is added to the mixture, grinding continues until the particle size is less than or equal to 20 microns. Then ultrasonic treatment is conducted at room temperature for 0.5 h to 1 h to allow more silicone oil to be bound to the slow-release material by bonding. Finally, the silicone oil can be dried to a semi-solid state by heating and solidifying and bound to the slow-release material in a colloidal form. Thus, slow-release particles can be obtained. Here, by first mixing the silicone oil and the slow-release material and grinding until the particle size is less than or equal to 30 microns, the silicone oil and the slow-release material can be evenly mixed. After that, grinding under the condition of a catalyst until the particle size is smaller than or equal to 20 microns makes the silicone oil firmly absorbed by the slow-release material at its exterior. Besides ultrasonic treatment, other methods known to those skilled in the art can also be used to achieve the bonding between the silicone oil and the slow-release material, such as heating and pressurizing, and / or the use of acidic / basic salts, etc. Furthermore, when the particle size of the slow-release material is smaller than 30 microns, the first grinding can be omitted, and a stirring process can optionally be provided, or the second grinding process can be performed directly. In addition, when the particle size of the slow-release material is smaller than 20 microns, the second grinding process can be further omitted, and a stirring process can optionally be provided.

[0104] Preparation of the Ceramic Coating Material

[0105] After preparing the ceramic coating material precursor and the slow-release particle, the slow-release particles and the ceramic coating material precursor can be mixed to prepare a first ceramic coating material according to an exemplary embodiment.

[0106] According to an exemplary embodiment, during the preparation process of the first ceramic coating material, based on the total weight of the ceramic coating material, 61 to 92 parts by weight of the ceramic coating material precursor can be mixed with 5 to 30 parts by weight of the slow-release particles. For example, the weight ratio relationship between A, B, C and the slow-release particles D can be (20-30): (40-60): (1-2): (5-30). For a ceramic coating material that comprises different contents and / or sizes of the slow-release particles, the required size and / or content of the slow-release particles can be added to the first ceramic coating material. After the ceramic coating material precursor and the slow-release particles are mixed, the mixture can be stirred at 120 to 200 rpm for 6 to 8 hours to obtain the required first ceramic coating material.

[0107] In addition, although the above method describes obtaining the first ceramic coating material by separately preparing the ceramic coating material precursor and the slow-release particles and then mixing them up, it is also possible that the step of preparing the ceramic coating material precursor and the step of preparing the slow-release particles are combined. For example, after mixing the material B and the material C, the material A and the slow-release particles can be added to the mixture of the material B and the material C at the same time. For instance, 40 to 60 parts by weight of the material B can be mixed with 1 to 2 parts by weight of the material C, thereby adjusting the pH of the mixture to less than or equal to 4 by means of the acidity of the material C to obtain the first material. Then, the material A and the slow-release particles can be added to the first material. Here, the weight ratio between the material A, the slow-release particle, and the material B can be in the range of (20-30): (5-30): (40-60). In addition, different amounts of the slow-release particles can be adaptively added according to the requirements of different layers. When a ceramic coating comprises a plurality of sub-layers, for the first ceramic coating material forming the uppermost sub-layer, the weight ratio between the material A, the material B, and the slow-release particles can be (20-30): (40-60): (5-30). After mixing, the mixture can be stirred at 120 to 200 rpm for 6h to 8h, thereby obtaining the required ceramic coating material.

[0108] In some embodiments, in addition to preparing a first ceramic coating material containing the slow-release particles, it is also necessary to prepare a second ceramic coating material that does not contain the slow-release particles. The second ceramic coating material can be a ceramic coating material commonly used in the art, and therefore can be prepared using a conventional formula in the prior art.

[0109] According to an example, the second ceramic coating material can be prepared by the following method: (1) mixing silane and ethyl orthosilicate, stirring well, thereby obtaining a silane composition as component E ; (2) mixing silica sol with isopropyl alcohol with deionized water, and adding an emulsifier and a thickener, thereby obtaining a slurry as component F; (3) mixing formic acid, acetic acid, a buffer (for example, boric acid), and a catalyst (for example, zirconium acetate), to obtain a strongly acidic catalyst as component G; (4) mixing the above three components in sequence according to a mass ratio of E: F: G = (20-30): (40-60): (1-2), rolling and curing, thereby obtaining a second ceramic coating material. The mixing sequence and curing method are as follows: first mixing components F and G evenly according to the required parts, adjusting the pH to below 4, rolling and dispersing for 0.5 h, then adding the required parts of E and shaking, thereby obtaining the second ceramic coating material.

[0110] Preparation of the Ceramic Coating

[0111] After preparing and obtaining the first ceramic coating material and the second ceramic coating material, preparation of a first ceramic coating and a second ceramic coating can be performed.

[0112] The ceramic coating material can be sprayed using air spraying, with the following parameters: spraying distance of 160 mm; air pressure of 0.3 MPa; flow rate of 8L / min. In addition, when a plurality of sub-layers are provided, the above spraying parameters can be applied to any sub-layer. In addition, the method of forming a ceramic coating is not limited to air spraying, and various suitable layer-forming methods in the art can be used.

[0113] After air spraying, a single-layer ceramic coating or a ceramic coating with a plurality of sub-layers can be formed on a substrate. In order to improve the binding force between the ceramic coating 200 and the substrate 100, the substrate can be pre-treated. For example, the substrate can be sandblastfid with 60# brown corundum to form a roughness of 3 to 6 microns on a surface. The substrate is then cleaned and preheated to 40°C to 60°C, and then the ceramic coating is formed.

[0114] After air spraying, the resultant can be cured at a temperature of 230°C to 280°C for 10min to 15min to form a ceramic coating with a thickness of 10 microns to 80 microns.

[0115] According to an exemplary embodiment, when a single ceramic coating 200 is provided, 5.15 to 32.97 parts by weight of the slow-release particles can be dispersed in every 100 parts by weight of the ceramic coating 200. In addition, when a plurality of sub-layers (for example, 201 , 202) are provided, the content of the slow-release particles comprised in each sub-layer can gradually (for example, with a gradient) increase in a direction away from the substrate 100 and the uppermost sub-layer (for example, 202) can have 5.15 to 32.97 parts by weight of the slow-release particles dispersed in every 100 parts by weight of the sub-layer. Alternatively, the sub-layer(s) arranged below the uppermost sub-layer (for example, 202) can have the same or different contents of the slow-release particles that are less than the uppermost sub-layer (for example, 202) which can have 5.15 to 32.97 parts by weight of the slow-release particles dispersed in every 100 parts by weight of the sub-layer. In other words, the content of the slow-release particles in each sub-layer (for example, 201) arranged below the uppermost sub-layer is not limited to the range of 5.15 to 32.97 parts by weight of the slow-release particles dispersed in every 100 parts by weight of the sub-layer.

[0116] Based on the detailed description above in conjunction with exemplary embodiments, the ceramic coating material of the present invention comprises slow-release particles containing a slow-release material. Since the slow-release material has a disordered porous and / or layered structure, silicone oil can be adsorbed and bonded to the slow-release material, so as to form slow-release particles with slow-release effect. Release of the silicone oil is slowed during cooking, thereby maintaining durable non-stickiness.

[0117] Beneficial effects of the present invention are described below in conjunction with particular examples.

[0118] Embodiment 1

[0119] A ceramic coating material is formed by means of the following method.

[0120] S1 : mixing 80wt% methyltrimethoxysilane and 20wt% ethyl orthosilicate and stirring well to obtain a silane composition as component A;

[0121] S2: mixing evenly 30wt% AkzoNobel 1050 (silica sol), 8wt% titanium dioxide (pigment), 25wt% kaolin (filler), 3wt% Tween-80 (emulsifier), 1wt% water-based modified bentonite (thickener), 0.3wt% polyoxyethylene ether TRITONX-100 (wetting agent), 20wt% isopropyl alcohol, and the remainder of deionized water, then adding the mixture to a grinder, and grinding for 2 hours to fully disperse it and grind it to a particle size of no more than 15 microns, thereby obtaining a slurry as component B;

[0122] S3: mixing evenly 48 parts by weight of formic acid, 48 parts by weight of acetic acid, 1 part by weight of boric acid (buffer), and 0.5 part by weight of zirconium acetate (catalyst), thereby obtaining a strongly acidic catalyst as component C;

[0123] S4: mixing 58 parts by weight of hydroxyl silicone oil having a molecular weight of 3,000 and 42 parts by weight of vermiculite (slow-release material) having a particle size of 100 mesh to 3,000 mesh, then adding 3 parts by weight of a methoxysilane coupling agent, mixing well, and grinding until a particle size of no more than 30 microns, then adding 0.3 parts by weight of titanate (catalyst), continuing to grind until a particle size of no more than 20 microns, and then performing ultrasonic treatment at a room temperature of 22°C for 0.5 h, thereby obtaining slow-release particles as component D, the particle size of the slow-release particles as component D following a normal distribution;

[0124] S5: mixing the above four components sequentially according to a weight part ratio of A:B:C:D=20:40:1 :30, rolling and curing, thereby obtaining a ceramic coating material. The mixing sequence and curing method are as follows: first mixing 40 parts by weight of the component B and 1 part by weight of the component C evenly so as to adjust the pH to 4 by means of the component C, and rolling and dispersing for 0.5 h, then adding 20 parts by weight of the component A and shaking, then adding 30 parts by weight of the component D, stirring and reacting at 200 rpm for 8 hours, thereby obtaining the required ceramic coating material.

[0125] A non-stick cooking utensil is realized using the above-described ceramic coating material by means of the following method.

[0126] S6: treating a substrate. A stainless-steel substrate is sandblasted with 60# brown corundum to form a roughness of 3 microns on the surface;

[0127] S7: preheating. The sandblasted substrate is cleaned and preheated to 60°C;

[0128] S8: spraying. The ceramic coating material is sprayed by air spraying to form a film with a thickness of 40 microns. The parameters of the air spraying are as follows: spraying distance is 160 mm; air pressure is 0.3 MPa; flow is 8L / min.

[0129] S9: sintering. Curing is performed at a temperature of 250°C for 10 minutes. A non-stick cooking utensil of Embodiment 1 is obtained by the above method.

[0130] Embodiment 2

[0131] It differs from Embodiment 1 in that: the slow-release material is bentonite.

[0132] Embodiment 3

[0133] It differs from Embodiment 1 in that: the slow-release material is alpha alumina.

[0134] Embodiment 4

[0135] It differs from Embodiment 1 in that: the particle size of the slow-release particles is no larger than 15 microns, and the particle size of the component D, the slow-release particles, follows a normal distribution.

[0136] Embodiment 5

[0137] It differs from Embodiment 1 in that: the particle size of the slow-release particles is no larger than 10 microns, and the particle size of the component D, the slow-release particles, follows a normal distribution.

[0138] Embodiment 6

[0139] It differs from Embodiment 1 in that: the silicone oil is composed of 20wt% hydroxyl silicone oil with a molecular weight of 800, 60wt% hydroxyl silicone oil with a molecular weight of 3,000, and 20wt% hydroxyl silicone oil with a molecular weight of 12,000.

[0140] Embodiment 7

[0141] It differs from Embodiment 1 in that: the silicone oil is composed of 30wt% hydroxyl silicone oil with a molecular weight of 800, 40wt% hydroxyl silicone oil with a molecular weight of 3,000, and 30wt% hydroxyl silicone oil with a molecular weight of 12,000.

[0142] Embodiment 8

[0143] It differs from Embodiment 1 in that: the silicone oil is composed of 25wt% hydroxyl silicone oil with a molecular weight of 800, 50wt% hydroxyl silicone oil with a molecular weight of 3,000, and 25wt% hydroxyl silicone oil with a molecular weight of 12,000.

[0144] Embodiment 9

[0145] It differs from Embodiment 1 in that: the comoonent A, component B, component C, and component D are mixed sequentially according to a weight ratio of A:B:C:D=30:60:2:5.

[0146] Embodiment 10

[0147] It differs from Embodiment 1 in that: the component A, component B, component C, and component D are mixed sequentially according to a weight ratio of A:B:C:D=20:40:1 :8.

[0148] Embodiment 11

[0149] It differs from Embodiment 1 in that: the component A, component B, component C, and component D are mixed sequentially according to a weight ratio of A:B:C:D=20:40:1 :15.

[0150] Embodiment 12

[0151] It differs from Embodiment 1 in that: the component A, component B, component C, and component D are mixed sequentially according to a weight ratio of A:B:C:D=20:40:1 :23.

[0152] Embodiment 13

[0153] It differs from Embodiment 1 in that: 35 parts by weight of hydroxyl silicone oil with a molecular weight of 3,000 are mixed with 42 parts by weight of the slow-release material.

[0154] Embodiment 14

[0155] It differs from Embodiment 1 in that: 42 parts by weight of hydroxyl silicone oil with a molecular weight of 3,000 are mixed with 42 parts by weight of the slow-release material.

[0156] Embodiment 15

[0157] It differs from Embodiment 1 in that: 58 parts by weight of hydroxyl silicone oil with a molecular weight of 3,000 are mixed with 49 parts by weight of the slow-release material.

[0158] Embodiment 16

[0159] It differs from Embodiment 1 in that: 58 parts by weight of hydroxyl silicone oil with a molecular weight of 3,000 are mixed with 60 parts by weight of the slow-release material.

[0160] Embodiment 17

[0161] It differs from Embodiment 1 in that:

[0162] (1) a ceramic coating material 01 is prepared using the step S5 (2) it further comprises a step S51 , which differs from the step S5 only in that: the components A, B, C and D obtained in the steps S1 to S4 are mixed sequentially according to a weight ratio of A:B:C:D=22:40:1 :1 , to prepare a ceramic coating material 02;

[0163] (3) a first sub-layer with a film thickness of 25 microns is formed on the substrate using the ceramic coating material 02 by means of the air spraying method of Embodiment 1 , and a second sub-layer having a film thickness of 45 microns is formed on the first sub-layer using the ceramic coating material 01 by means of the air spraying method of Embodiment 1.

[0164] Embodiment 18

[0165] It differs from Embodiment 17 in that: the thickness of the first sub-layer is 10 microns.

[0166] Embodiment 19

[0167] It differs from Embodiment 17 in that: the thickness of the first sub-layer is 30 microns.

[0168] Embodiment 20

[0169] It differs from Embodiment 17 in that: the thickness of the second sub-layer is 10 microns.

[0170] Embodiment 21

[0171] It differs from Embodiment 17 in that: the thickness of the second sub-layer is 20 microns.

[0172] Embodiment 22

[0173] It differs from Embodiment 1 in that:

[0174] (1) a first ceramic coating material is prepared according to the step S5;

[0175] (2) a second ceramic coating material is prepared by means of the following method:

[0176] W1 : mixing 80wt% methyltrimethoxysilane and 20wt% ethyl orthosilicate and stirring well, thereby obtaining a silane composition as component E;

[0177] W2: mixing evenly 30wt% AkzoNobel 1050 (silica sol), 3wt% Tween-80 (emulsifier), 1wt% water-based modified bentonite (thickener), 20wt% isopropyl alcohol and the remainder of deionized water, thereby obtaining a slurry as component F; W3: mixing evenly 48 parts by weight of formic acid, 48 parts by weight of acetic acid, 1 part by weight of boric acid (buffer), and 0.5 part by weight of zirconium acetate (catalyst), thereby obtaining a strongly acidic catalyst as component G;

[0178] W4: mixing the above three components sequentially according to a weight ratio of E:F:G=20:40:1 , rolling and curing, thereby obtaining a second ceramic coating material. The mixing sequence and curing method are as follows: first mixing 40 parts by weight of the component F and 1 part by weight of the component G so as to adjust the pH to 4 by means of the component G, then rolling and dispersing for 0.5 h, then adding 20 parts by weight of the component E and shaking evenly, thereby obtaining the second ceramic coating material.

[0179] A non-stick cooking utensil comprising a first ceramic coating and a second ceramic coating is realized using the first ceramic coating material and the second ceramic coating material by means of the following method.

[0180] B1 : treating a substrate. A stainless-steel substrate is sandblasted with 60# brown corundum to form a roughness of 3 microns on the surface;

[0181] B2: preheating. The sandblasted substrate is cleaned and preheated to 60°C;

[0182] B3: spraying. The first ceramic coating material is sprayed onto the substrate by air spraying to form a first ceramic coating with a thickness of 80 microns, and the second ceramic coating material is sprayed onto the first ceramic coating to form a second ceramic coating with a thickness of 8 microns. The parameters of the air spraying are as follows: spraying distance at 160 mm; air pressure of 0.3 MPa; flow rate of 8L / min.

[0183] B4: sintering. Curing is performed at a temperature of 250°C for 10 minutes.

[0184] Comparison 1

[0185] It differs from Embodiment 1 in that: the step S4 is omitted. In other words, in the step S5, the components A, B, and C are mixed sequentially according to a weight ratio of A:B:C=20:40:1 , and the ceramic material obtained is used to realize a non-stick cooking utensil.

[0186] Comparison 2

[0187] It differs from Embodiment 1 in that: 30 parts by weight of hydroxyl silicone oil with a molecular weight of 3,000 are mixed with 60 parts by weight of vermiculite.

[0188] Comparison 3 It differs from Embodiment 1 in that: 60 parts by weight of hydroxyl silicone oil with a molecular weight of 3,000 are mixed with 40 parts by weight of vermiculite.

[0189] Comparison 4

[0190] It differs from Embodiment 17 in that: the second sub-layer in located on the substrate, and the first sub-layer is located above the second sub-layer.

[0191] The non-stickiness of the non-stick cooking utensils of the above-described Embodiments 1 to 22 and Comparisons 1 to 4 is respectively tested, with the results of the testing shown in the table below. Performance testing

[0192] The performance of the cooking utensils obtained above is tested by means of the following methods:

[0193] (1) durable non-stickiness testing method: in reference to the egg frying non-stickiness test in 4.2.1 of GB_T 32095.2-2015, the unit is number of times. The greater number of times, the longer the life is. The non-stickiness is evaluated once every 1 ,000 times, and the number of times when non-stickiness reaches level III is recorded.

[0194] (2) surface abrasion resistance testing method: the surface abrasion resistance test in 4.3.1 of GB_T 32095.2-2015, wherein, a 3M7447 scouring pad is used, and a force of 15 N is applied, at a frequency of 33 times per minute, with the scouring pad being replaced once every 500 times.

[0195] By comparing and analyzing Embodiments 1 to 22 of the present invention and Comparison 1 to 4, it can be seen that: the existing conventional ceramic coating in Comparison 1 has a durable non-stickiness of no more than 500 times. The silicone oil in Comparison 2 cannot effectively provide a slow-release effect due to its relatively low content. The content of the slow-release material in Comparison 3 is too low, and the amount of bound silicone oil is relatively small, thus the slow-release effect cannot be provided, either. The durable non-stickiness of the ceramic coating according to the present invention is 8,000 to 25,000 times. Embodiments 6 to 8 provide better non-stickiness compared to Embodiment 1 , which shows that a formulation with silicone oil of different molecular weights can improve the performance of the slow-release particle. Embodiments 17 to 19 provide better non-stickiness compared to Embodiment 1 , which shows that providing a plurality of sub-layers with different contents of the slow-release particles can also improve the non-stickiness of the coating. Embodiment 22 provides better non-stickiness compared to Embodiment 1 , which shows that providing a sealing layer in addition to a slow-release layer can also improve the non-stickiness of the coating. In addition, in Comparison 4, even though two sub-layers are provided, the content of the slow-release particles in the uppermost sub-layer is lower than the content of the slow-release particles in the sub-layer below. The test performance of the two-layer ceramic coating thus formed is lower than the test performance of the ceramic coating in Embodiment 17. Compared to Comparisons 1 to 4, the ceramic coating according to the present invention has excellent durable non-stickiness.

[0196] Although one or more embodiments of the present invention have been described with reference to the accompanying drawings, those of ordinary skill in the art will understand that various modifications may be made to them in form and details without departing from the spirit and scope defined by the claims.

Claims

Claims1 . Slow-release particles, characterized in that, the slow-release particles comprise :- a slow-release material having a porous structure and / or layered structure;- silicone oil, binding to the slow-release material; wherein, the slow-release material comprises at least one of vermiculite, zeolite, bentonite, diatomaceous earth, alpha alumina, silica aerogel, fumed silica, amorphous silica, hollow glass micropowder, porous silicate, layered silicate, porous phosphate, layered phosphate, porous carbonate, layered carbonate, porous sulfate and layered sulfate.

2. The slow-release particles of claim 1 , characterized in that, the particle size of the slow-release particles is smaller than or equal to 20 microns.

3. The slow-release particles of claim 1 or 2, characterized in that, by weight percentage, the silicone oil comprises 20%-30% low molecular weight silicone oil, 40%-60% medium molecular weight silicone oil, and 20%-30% high molecular weight silicone oil; wherein, the molecular weight of the low molecular weight silicone oil is between 500 to 1 ,000, the molecular weight of the medium molecular weight silicone oil is between 3,000 to 6,000, and the molecular weight of the high molecular weight silicone oil is between 12,000 to 30,000.

4. A method of preparing the slow-release particles of any one of claims 1 to 3, characterized in that, the method comprises:- providing a slow-release material and silicone oil;- mixing 35 to 58 parts by weight of the slow-release material with 42 to 60 parts by weight of the silicone oil, so that the silicone oil is bound to the slow-release particle, so as to obtain the slow-release particle.

5. The method of claim 4, characterized in that, in the mixing step, the silicone oil, the slow-release material, and a coupling agent are mixed evenly and ground to a particle size of smaller than or equal to 30 microns, a catalyst is added, and the grinding continues until a particle size of smaller than or equal to 20 microns.

6. The method of claim 5, characterized in that, the particle size of the slow-release material is 100 mesh to 3,000 mesh.

7. The method of claim 5 or 6, characterized in that, subsequently, ultrasonic treatment is performed during 0.5 h to 1 h, so as to obtain the slow-release particle.

8. A ceramic coating, characterized in that, the ceramic coating comprises a ceramiccoating material precursor and the slow-release particles of any one of claims 1 to 3, dispersed in the ceramic coating material precursor.

9. The ceramic coating of claim 8, characterized in that, 5.15-32.97 parts by weight of the slow-release particles is comprised in every 100 parts by weight of the ceramic coating material.

10. The ceramic coating of claim 8 or 9, characterized in that, the particle size of the slow-release particles is smaller than or equal to 15 microns.

11. The ceramic coating of any one of claims 8 to 10, characterized in that, the ceramic coating comprises a single layer, and the thickness of the single layer ranges from 10 microns to 80 microns.

12. The ceramic coating of any one of claims 8 to 11 , characterized in that, the ceramic coating comprises at least two sub-layers, and at least the uppermost sub-layer of the at least two sub-layers comprises slow-release particles.

13. The ceramic coating of claim 12, characterized in that, the thickness of each sub-layer is not less than 10 microns, and the sum of the thickness of each sub-layer is not more than 80 microns.

14. The ceramic coating of any one of claims 12 to 13, characterized in that, the content of the slow-release particles comprised in each sub-layer is different from each other.

15. The ceramic coating of claim 14, characterized in that, the ceramic coating is applied on a substrate, and the content of the slow-release particles in each sub-layer increases in a direction away from the substrate.

16. The ceramic coating of any one of claims 8 to 15, characterized in that, the particle size of the slow-release particles comprised in each sub-layer in the ceramic coating is different from each other.

17. A stacked ceramic coating, characterized in that, the ceramic coating comprises:- the ceramic coating of any one of claims 8 to 16, as a first ceramic coating; and- a second ceramic coating located above the first ceramic coating as a sealing layer and formed by means of a second ceramic coating material.

18. The stacked ceramic coating of claim 17, characterized in that, the second ceramic coating has a thickness of 8 to 20 microns.

19. The stacked ceramic coating of claim 17 or 18, characterized in that, the ceramiccoating material precursor comprises the same material as the second ceramic coating material.

20. A non-stick utensil, characterized in that, the non-stick utensil comprises:- a substrate, a surface of which has a surface roughness of 3 microns to 15 microns;- the ceramic coating of any one of claims 8 to 16 or the stacked ceramic coating of any one of claims 17 to 19, located on the surface of the substrate.

21. The non-stick utensil of claim 20, characterized in that, the substrate comprises two or more layers constituted by at least two materials selected among aluminum, aluminum alloys, titanium, titanium alloys, iron, and stainless steel.

22. The non-stick utensil of claim 20 or 21 , characterized in that, the substrate comprises a base layer and a functional layer arranged between the base layer and the ceramic coating or the stacked ceramic coating, and a surface of the functional layer has a surface roughness of 3 microns to 15 microns.

23. A method of preparing a ceramic coating material, characterized in that, the method comprises:- preparing a ceramic coating material precursor;- preparing slow-release particles by means of the method of any one of claims 4 to 7; and,- mixing the ceramic coating material precursor with the slow-release particle, so as to obtain the ceramic coating material.

24. The method of claim 23, characterized in that, the step of preparing a ceramic coating material precursor comprises:S1 : preparing a material A, a material B, and a material C, wherein: the material A comprises silane; the material B comprises silica sol and a filler as essential components, and optionally, a pigment, a wetting agent, a thickener and an emulsifier as non-essential components, and a solvent; the material C comprises an organic acid as an essential component, and optionally, a pH buffer and a catalyst as non-essential components;S2: mixing the material B and the material C, and adjusting the pH of the mixture to lower than or equal to 4, thereby obtaining a first material; andS3: mixing the material A with the first material, thereby obtaining the ceramic coating material precursor.

25. A method of preparing a ceramic coating material, characterized in that, the methodcomprises:S1 : preparing a material A, a material B, and a material C, wherein: the material A comprises silane; the material B comprises silica sol and a filler as essential components, and optionally, a pigment, a wetting agent, a thickener and an emulsifier as non-essential components, and a solvent; the material C comprises an organic acid as an essential component, and optionally, a pH buffer and a catalyst as non-essential components; slow-release particles are prepared by means of the method of any one of claims 4 to 7;S2: mixing the material B and the material C, and adjusting the pH of the mixture to lower than or equal to 4, thereby obtaining a first material; andS3: mixing the material A and the slow-release particles with the first material, so as to obtain the ceramic coating material.

26. The method of any one of claims 22 to 25, characterized in that, the silane comprises at least one of methyltrimethoxysilane, methyltriethoxysilane and dimethyldimethoxysilane, and the material A further comprises ethyl orthosilicate; wherein, the material A comprises 80-97 wt.% of the silane, and 3-20 wt.% of the ethyl orthosilicate.

27. A method of preparing a ceramic coating, characterized in that, the method comprises:- preparing a ceramic coating material by means of the method of any one of claims 23 to 26; and- forming the ceramic coating of any one of claims 8 to 16 on a substrate by the ceramic coating material by means of a layer forming process.

28. The method of claim 27, characterized in that, the ceramic coating comprises a first sub-layer arranged on the substrate and a second sub-layer, the method comprising:- preparing a ceramic coating material comprising: a first ceramic coating material 01 comprising a ceramic coating material precursor and optionally, slow-release particles; and, a first ceramic coating material 02 comprising a ceramic coating material precursor and slow-release particles; and- forming a first sub-layer on the substrate by the first ceramic coating material 01 by means of a layer forming process, and forming a second sub-layer on the first sub-layer by the first ceramic coating material 02, the content of the slow-release particles comprised in the first sub-layer being different from the content of the slow-release particles comprised in the second sub-layer.

29. The method of claim 28, characterized in that, the content of the slow-release particlescomprised in the first sub-layer is lower than the content of the slow-release particles comprised in the second sub-layer.

30. The method of claim 28 or 29, characterized in that, the content of the slow-release particles comprised in the first sub-layer is such that 0 to less than 32.97 parts by weight of the slow-release particles are comprised in every 100 parts by weight of the first sub-layer, and the content of the slow-release particles comprised in the second sub-layer is such that 5.15 to 32.97 parts by weight of the slow-release particles are comprised in every 100 parts by weight of the second sub-layer.31 . The method of any one of claims 28 to 30, characterized in that, - the ceramic coating further comprises a third sub-layer arranged between the first sub-layer and the second sub-layer;- the ceramic coating material further comprises a third ceramic coating material comprising a ceramic coating material precursor and slow-release particles; and the method further comprises forming the third sub-layer on the first sub-layer by the third ceramic coating material, and then forming the second sub-layer on the third sub-layer; wherein, the content of the slow-release particles comprised in the third sub-layer is different from the content of the slow-release particles comprised in each of the first sub-layer and the second sub-layer.

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