A bio-based powder coating with insulation, heat insulation and anti-fingerprint properties and a preparation method thereof

Abstract

The invention discloses a bio-based powder coating with insulation, heat insulation and anti-fingerprint performance and a preparation method thereof, belonging to the field of powder coating technology. The powder coating includes the following components in parts by weight: 439-593 parts of modified bio-based epoxy resin, 20-28 parts of dicyandiamide, 55-65 parts of hydroxy polyester resin, 4-8 parts of isocyanate, 0.3-0.8 parts of acrylic acid, 40-60 parts of modified glass microbeads, 3-8 parts of glass fiber, 7-15 parts of talc, 0.3-0.8 parts of thermal expansion agent, 20-40 parts of pigment, 2-4 parts of leveling agent, and 0.5-1.5 parts of benzoin. The powder coating has the advantages of good insulation performance, heat insulation performance and anti-fingerprint performance, and can effectively solve the problems of powder coatings in the prior art.

Description

Technical Field

[0001] The present invention belongs to the technical field of powder coatings, and in particular relates to a bio-based powder coating with insulating, heat-insulating and anti-fingerprint properties and a preparation method thereof. Background Art

[0002] Powder coating is a solvent-free, solid coating applied to surfaces via methods such as electrostatic spraying and fluidized bed coatings. It then forms a coating after being heated and cured. Compared to traditional liquid coatings, it offers advantages such as environmental friendliness, high efficiency, and superior performance. Powder coatings are primarily composed of resin, curing agent, pigment / filler, and additives, which are mixed, pressed, crushed, ground, and sieved. Resin, as the primary film-forming substance, determines the coating's fundamental properties. Powder coating is typically applied to the workpiece surface via electrostatic spraying, then heated in an oven, where the powder solidifies into a film.

[0003] Powder coatings, with their economical, environmentally friendly, efficient, and superior performance advantages, are gradually replacing organic solvent-based coatings and becoming a key development direction in the coatings industry. As the powder coatings market expands, performance requirements are also becoming increasingly demanding. Existing powder coatings are mostly single-function and lack thermal insulation and fingerprint removal properties, limiting their application in specific areas. Summary of the Invention

[0004] In response to the above-mentioned deficiencies in the prior art, the present invention provides a bio-based powder coating with insulating, heat-insulating and anti-fingerprint properties and a preparation method thereof. The powder coating has the advantages of good insulating, heat-insulating and anti-fingerprint properties, and can effectively solve the problems existing in the powder coatings in the prior art.

[0005] To achieve the above-mentioned purpose, the technical solution adopted by the present invention to solve the technical problem is:

[0006] A bio-based powder coating with insulating, heat-insulating and anti-fingerprint properties comprises the following components in parts by weight: 439-593 parts of a modified bio-based epoxy resin, 20-28 parts of dicyandiamide, 55-65 parts of a hydroxy polyester resin, 4-8 parts of isocyanate, 0.3-0.8 parts of acrylic acid, 40-60 parts of modified glass microbeads, 3-8 parts of glass fiber, 7-15 parts of talc, 0.3-0.8 parts of a thermal expansion agent, 20-40 parts of a pigment, 2-4 parts of a leveling agent, and 0.5-1.5 parts of benzoin.

[0007] Furthermore, the preparation method of the modified bio-based epoxy resin is as follows: ethanol and water are mixed, the pH value of the mixed solution is adjusted to 4-5, a silane coupling agent is added dropwise thereto, and the mixture is reacted at 4-30°C with stirring for 1.5-3 hours to obtain a silane coupling agent hydrolyzate; under nitrogen protection, the bio-based epoxy resin is heated to 75-85°C, and then the silane coupling agent hydrolyzate is added dropwise thereto with stirring, the mixture is stirred for reaction, and after the reaction is completed, the solvent is removed by rotary evaporation to obtain a modified bio-based epoxy resin.

[0008] Furthermore, the mass ratio of the silane coupling agent, ethanol and water is 8-12:75-85:8-12; and the mass ratio of the bio-based epoxy resin to the silane coupling agent is 100:1-2.

[0009] Furthermore, the bio-based epoxy resin includes itaconic acid-based epoxy resin and cardanol-based epoxy resin, and the silane coupling agent is KH560.

[0010] Furthermore, the isocyanate is triphenylmethane triisocyanate.

[0011] Furthermore, the preparation method of the modified glass microspheres is as follows:

[0012] (1) In an ice-water bath, ethanol and acetylacetone are mixed, and tetrabutyl titanate is added dropwise thereto to prepare a mixed solution, and then an aqueous solution containing aqueous ammonia is added dropwise thereto, and the pH of the mixed solution is adjusted to 3-4, and stirring is continued to prepare a transparent sol; glass microspheres are mixed with the transparent sol and ultrasonically dispersed, and then the solvent is evaporated and removed under stirring, and the product is calcined under nitrogen protection to prepare titanium dioxide-coated glass microspheres;

[0013] (2) Perfluorooctyltriethoxysilane is vaporized and deposited on the surface of titanium dioxide-coated glass microspheres, and then annealed under nitrogen conditions at 110-130°C to obtain modified glass microspheres.

[0014] Furthermore, in step (1), the molar ratio of tetrabutyl titanate, ethanol, acetylacetone and water is 1:18-22:0.4-0.6:0.2-0.4; the solid-liquid ratio of glass microspheres to transparent sol is 1:1.5-2.5; the calcination temperature is 280-320° C., and the calcination time is 1.5-3 h.

[0015] Furthermore, in step (2), the volume mass ratio of perfluorooctyltriethoxysilane to titanium dioxide-coated glass microspheres is 5 ml:90-110 g; and the vaporization temperature of perfluorooctyltriethoxysilane is 140-160°C.

[0016] The method for preparing the above-mentioned bio-based powder coating having insulating, heat-insulating and anti-fingerprint properties comprises the following steps:

[0017] (1) Mixing a partially modified bio-based epoxy resin and dicyandiamide at a mass ratio of 100:5 to prepare a mixture 1;

[0018] (2) mixing the remaining modified bio-based epoxy resin and part of the hydroxy polyester resin in a mass ratio of 1:1 to prepare mixture 2;

[0019] (3) mixing the remaining hydroxy polyester resin and isocyanate in a mass ratio of 4:1 to prepare a mixture 3;

[0020] (4) mixing acrylic acid, modified glass microbeads, glass fiber, talc, thermal expansion agent, pigment, leveling agent and benzoin to prepare mixture 4;

[0021] (5) Mixing mixture 1, mixture 2, mixture 3 and mixture 4 to obtain a total mixture;

[0022] (6) The total mixture is heated, extruded, cooled, tableted, crushed, ground, and sieved in sequence to obtain a powder coating.

[0023] Furthermore, the heating extrusion temperature in step (6) is divided into three stages, the heating temperature in the first stage is 85-95°C, the heating temperature in the second stage is 96-105°C, and the heating temperature in the third stage is 96-105°C.

[0024] The beneficial effects produced by the present invention are:

[0025] 1. In the process of modifying the bio-based epoxy resin in the present invention, the silane coupling agent can undergo a condensation reaction with the epoxy resin to form a Si-OC covalent bond, thereby preparing a bio-based epoxy resin containing siloxane groups on the surface. The grafted siloxane groups can reduce the surface energy of the resin and enhance the bonding ability between the resin and the inorganic filler interface, thereby improving the insulation and hydrophobicity of the powder coating, thereby improving the insulation and anti-fingerprint properties of the coating.

[0026] 2. In the process of surface modification of the glass microspheres in the present invention, anatase phase can be attached to the surface of the glass microspheres, which is used to improve the infrared reflection performance of the glass microspheres, ultimately reducing the absorption of heat and improving the thermal insulation performance of the coating; continuing to deposit perfluorooctyltriethoxysilane on the surface of the glass microspheres can form a silane film layer on the surface of the glass microspheres, so that a hydrophobic film is formed on the surface of the glass microspheres, thereby improving the hydrophobicity of the glass microspheres. The modified glass microspheres can not only improve the thermal insulation performance of the coating, but also improve the anti-fingerprint effect of the coating.

[0027] 3. In the present invention, epoxy resin is premixed with a dicyandiamide curing agent and an isocyanate curing agent, and a hydroxy polyester resin is premixed with an isocyanate. After curing, these materials form a uniform, dense, three-dimensional cross-linked network structure within the coating. This increases the density of the coating, effectively blocks charge migration paths, inhibits electron hopping conduction, and thus improves insulation. The dense network structure also enhances thermal insulation and anti-fingerprint properties. Furthermore, by increasing the amount of epoxy resin used, the encapsulation effect of fillers such as glass microspheres, glass fibers, and talc is enhanced, thereby increasing the service life of the coating.

[0028] 4. In the preparation method of the present invention, the resin raw materials and different curing agents are premixed separately, which can avoid premature curing of the resin, improve the stability of the powder coating, and further improve the use effect of the powder coating. Specifically, premixing the modified bio-based epoxy resin with dicyandiamide can avoid dicyandiamide from contacting acidic or hydroxyl components, ensuring that the curing reaction occurs in a high-temperature environment after coating; premixing the isocyanate with the hydroxy polyester resin can limit the reaction of the isocyanate group with other groups such as carboxyl groups, thereby reducing the occurrence of side reactions; premixing the remaining raw materials such as modified glass microbeads and glass fibers with acrylic acid can achieve coating of the liquid raw material on the surface of the solid raw material, improve the subsequent dispersion uniformity in the coating, reduce the generation of air gaps after the coating is cured, and further improve the anti-fingerprint performance of the coating.

[0029] 5. In the present invention, by heating and extruding in stages and performing preliminary cross-linking, the material is prevented from shrinking rapidly and cracking, thereby reducing the occurrence of defects. By the final heating, complete cross-linking is achieved to form a defect-free dense structure. The dense structure can reduce the risk of leakage and, at the same time, improve the thermal insulation and anti-fingerprint properties. BRIEF DESCRIPTION OF THE DRAWINGS

[0030] Figure 1 The following are the physical demonstrations of the anti-fingerprint effect of the sample in Example 1: a is the physical picture of the sample after the first fingerprint is pressed, b is the physical picture of the sample 2 seconds after the first fingerprint is pressed, c is the physical picture of the sample after the second fingerprint is pressed, d is the physical picture of the sample after the third fingerprint is pressed, and e is the physical picture of the sample after the third fingerprint is pressed 6 seconds later;

[0031] Figure 2 The anti-fingerprint effect of the sample in Comparative Example 1 is shown in Figure a, after the first fingerprint is pressed, Figure b, after the second fingerprint is pressed, and Figure c, after the third fingerprint is pressed.

[0032] Figure 3 The anti-fingerprint effect of the sample in Comparative Example 2 is shown in Figure a, after the first fingerprint is pressed, Figure b, after the second fingerprint is pressed, and Figure c, after the third fingerprint is pressed.

[0033] Figure 4 These are the actual demonstration pictures of the anti-fingerprint effect of the sample in comparative example 3, a is the actual picture of the sample after pressing the fingerprint for the first time, b is the actual picture of the sample after pressing the fingerprint for the second time, and c is the actual picture of the sample after pressing the fingerprint for the third time. DETAILED DESCRIPTION

[0034] In order to make the purpose, technical solutions and advantages of the present invention more clearly understood, the present invention is further described in detail below in conjunction with the embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not intended to limit the present invention. That is, the embodiments described are only part of the embodiments of the present invention, rather than all embodiments.

[0035] Therefore, the detailed description of the embodiments of the present invention provided below is not intended to limit the scope of the invention as claimed, but is merely intended to represent selected embodiments of the present invention. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention without creative work are within the scope of protection of the present invention.

[0036] It should be noted that relational terms such as "first" and "second" are used only to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any actual relationship or order between these entities or operations. Moreover, the terms "comprises," "comprising," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus comprising a series of elements includes not only those elements, but also other elements not explicitly listed, or elements inherent to such process, method, article, or apparatus. In the absence of further limitations, an element defined by the phrase "comprising a ..." does not exclude the presence of other identical elements in the process, method, article, or apparatus comprising the element.

[0037] The features and performance of the present invention are further described in detail below with reference to the embodiments.

[0038] Example 1

[0039] A bio-based powder coating with insulating, heat-insulating and anti-fingerprint properties comprises the following components in parts by weight: 476 parts of modified cardanol-based epoxy resin, 22 parts of dicyandiamide, 60 parts of hydroxy polyester resin, 6 parts of triphenylmethane triisocyanate, 0.5 parts of acrylic acid, 50 parts of modified glass microbeads, 5 parts of glass fiber, 10 parts of talc, 0.5 parts of thermal expansion agent, 30 parts of pigment, 3 parts of leveling agent, and 1 part of benzoin.

[0040] The modified cardanol-based epoxy resin is prepared by mixing ethanol and water, adjusting the pH value of the mixed solution to 4, adding a silane coupling agent KH560 dropwise thereto, and reacting at 15° C. under stirring for 2 hours to obtain a KH560 hydrolyzate, wherein the mass ratio of KH560, ethanol, and water is 10:80:10; then, under nitrogen protection, heating the cardanol-based epoxy resin to 80° C., and adding the KH560 hydrolyzate dropwise thereto under stirring, wherein the mass ratio of the cardanol-based epoxy resin to the KH560 hydrolyzate is 100:1.5, stirring and reacting for 2 hours, and after the reaction is completed, rotary evaporation is performed at 60° C. to remove the solvent to obtain a modified cardanol-based epoxy resin;

[0041] The preparation method of modified glass microspheres is as follows: (1) in an ice-water bath, ethanol and acetylacetone are mixed, and tetrabutyl titanate is added dropwise thereto, and then an aqueous solution containing aqueous ammonia is added dropwise thereto, and the pH of the mixed solution is adjusted to 4, and stirring is continued to obtain a transparent sol, wherein the molar ratio of tetrabutyl titanate, ethanol, acetylacetone and water is 1:20:0.5:0.3; the glass microspheres and the transparent sol are mixed in a solid-liquid ratio of 1:2 and ultrasonically dispersed, and then the solvent is evaporated and removed under stirring, and then the product is calcined at 300°C for 2h under nitrogen protection to obtain titanium dioxide-coated glass microspheres;

[0042] (2) Perfluorooctyltriethoxysilane was vaporized at 150°C and then deposited on the surface of titanium dioxide-coated glass microspheres. The volume mass ratio of perfluorooctyltriethoxysilane to titanium dioxide-coated glass microspheres was 5 ml:100 g. The modified glass microspheres were then annealed at 120°C in nitrogen to obtain modified glass microspheres.

[0043] The preparation method of the above-mentioned bio-based powder coating having insulating, heat-insulating and anti-fingerprint properties comprises the following steps:

[0044] (1) Mixing a partially modified cardanol-based epoxy resin and dicyandiamide at a mass ratio of 100:5 to prepare a mixture 1;

[0045] (2) mixing the remaining modified cardanol-based epoxy resin and part of the hydroxy polyester resin in a mass ratio of 1:1 to prepare a mixture 2;

[0046] (3) mixing the remaining hydroxy polyester resin and triphenylmethane triisocyanate in a mass ratio of 4:1 to prepare a mixture 3;

[0047] (4) mixing acrylic acid, modified glass microbeads, glass fiber, talc, thermal expansion agent, pigment, leveling agent and benzoin to prepare mixture 4;

[0048] (5) Mixing mixture 1, mixture 2, mixture 3 and mixture 4 to obtain a total mixture;

[0049] (6) The total mixture is heated and extruded. The feed speed of the extruder is 30 rpm, the main machine speed is 50 rpm, and the extrusion temperature is divided into three stages. The heating temperature of the first stage is 90 °C, the heating temperature of the second stage is 100 °C, and the heating temperature of the third stage is 100 °C. Then, the mixture is cooled, tableted, crushed, ground, and sieved in sequence to obtain a powder coating with a particle size of D50 = 40 μm ± 5 μm. Among them, the tableting speed is 20 rpm, the feed speed during grinding is 25 rpm, the main mill speed is 50 rpm, the auxiliary mill speed is 25 rpm, and the screen mesh size is 200 mesh.

[0050] Example 2

[0051] A bio-based powder coating with insulating, heat-insulating and anti-fingerprint properties comprises the following components in parts by weight: 593 parts of modified itaconic acid-based epoxy resin, 28 parts of dicyandiamide, 65 parts of hydroxy polyester resin, 8 parts of triphenylmethane triisocyanate, 0.3 parts of acrylic acid, 40 parts of modified glass microbeads, 3 parts of glass fiber, 15 parts of talc, 0.3 parts of thermal expansion agent, 20 parts of pigment, 4 parts of leveling agent, and 0.5 parts of benzoin.

[0052] The modified itaconic acid-based epoxy resin is prepared by mixing ethanol and water, adjusting the pH value of the mixed solution to 4, adding KH560 dropwise thereto, and reacting at 20° C. under stirring for 1.5 hours to obtain a KH560 hydrolyzate, wherein the mass ratio of KH560, ethanol, and water is 8:80:12; then, heating the itaconic acid-based epoxy resin to 85° C. under nitrogen protection, and adding the KH560 hydrolyzate dropwise thereto under stirring, wherein the mass ratio of the itaconic acid-based epoxy resin to the KH560 hydrolyzate is 100:1, stirring and reacting for 2 hours, and after the reaction is completed, removing the solvent by rotary evaporation at 60° C. to obtain the modified itaconic acid-based epoxy resin;

[0053] The preparation method of modified glass microspheres is as follows: (1) in an ice-water bath, ethanol and acetylacetone are mixed, and tetrabutyl titanate is added dropwise thereto, and then an aqueous solution containing aqueous ammonia is added dropwise thereto, and the pH of the mixed solution is adjusted to 3, and stirring is continued to prepare a transparent sol, wherein the molar ratio of tetrabutyl titanate, ethanol, acetylacetone and water is 1:18:0.6:0.2; the glass microspheres and the transparent sol are mixed at a solid-liquid ratio of 1:1.5 and ultrasonically dispersed, and then the solvent is evaporated and removed under stirring, and then the product is calcined at 280°C for 3 hours under nitrogen protection to prepare titanium dioxide-coated glass microspheres;

[0054] (2) Perfluorooctyltriethoxysilane was vaporized at 140°C and then deposited on the surface of titanium dioxide-coated glass microspheres. The volume mass ratio of perfluorooctyltriethoxysilane to titanium dioxide-coated glass microspheres was 5 ml:90 g. The modified glass microspheres were then annealed at 110°C under nitrogen conditions to obtain modified glass microspheres.

[0055] The preparation method of the above-mentioned bio-based powder coating having insulating, heat-insulating and anti-fingerprint properties comprises the following steps:

[0056] (1) Mixing a portion of the modified itaconic acid-based epoxy resin and dicyandiamide at a mass ratio of 100:5 to prepare a mixture 1;

[0057] (2) mixing the remaining modified itaconic acid-based epoxy resin and part of the hydroxy polyester resin in a mass ratio of 1:1 to prepare a mixture 2;

[0058] (3) mixing the remaining hydroxy polyester resin and triphenylmethane triisocyanate in a mass ratio of 4:1 to prepare a mixture 3;

[0059] (4) mixing acrylic acid, modified glass microbeads, glass fiber, talc, thermal expansion agent, pigment, leveling agent and benzoin to prepare mixture 4;

[0060] (5) Mixing mixture 1, mixture 2, mixture 3 and mixture 4 to obtain a total mixture;

[0061] (6) The total mixture is heated and extruded. The feed speed of the extruder is 30 rpm, the main machine speed is 50 rpm, and the extrusion temperature is divided into three stages. The heating temperature of the first stage is 85 ° C, the heating temperature of the second stage is 96 ° C, and the heating temperature of the third stage is 96 ° C. Then, the total mixture is cooled and tableted, crushed, ground, and sieved in sequence to obtain a powder coating with a particle size of D50 = 40 μm ± 5 μm. Among them, the tableting speed is 20 rpm, the feed speed during grinding is 25 rpm, the main mill speed is 50 rpm, the auxiliary mill speed is 25 rpm, and the screen mesh size is 200 mesh.

[0062] Example 3

[0063] A bio-based powder coating with insulating, heat-insulating and anti-fingerprint properties comprises the following components in parts by weight: 439 parts of modified cardanol-based epoxy resin, 20 parts of dicyandiamide, 55 parts of hydroxy polyester resin, 4 parts of triphenylmethane triisocyanate, 0.8 parts of acrylic acid, 60 parts of modified glass microbeads, 8 parts of glass fiber, 7 parts of talc, 0.8 parts of thermal expansion agent, 40 parts of pigment, 2 parts of leveling agent, and 1.5 parts of benzoin.

[0064] The modified cardanol-based epoxy resin is prepared by mixing ethanol and water, adjusting the pH value of the mixed solution to 5, adding a silane coupling agent KH560 dropwise thereto, and reacting at 15° C. under stirring for 3 hours to obtain a KH560 hydrolyzate, wherein the mass ratio of KH560, ethanol, and water is 12:80:8; the mass ratio of the cardanol-based epoxy resin to KH560 is 100:2; then, under nitrogen protection, the cardanol-based epoxy resin is heated to 75° C., and the KH560 hydrolyzate is added dropwise thereto under stirring, the mass ratio of the cardanol-based epoxy resin to the KH560 hydrolyzate is 100:2, and the reaction is stirred for 2 hours. After the reaction is completed, the solvent is removed by rotary evaporation at 60° C. to obtain a modified cardanol-based epoxy resin;

[0065] The preparation method of modified glass microspheres is as follows: (1) in an ice-water bath, ethanol and acetylacetone are mixed, and tetrabutyl titanate is added dropwise thereto, and then an aqueous solution containing aqueous ammonia is added dropwise thereto, and the pH of the mixed solution is adjusted to 4, and stirring is continued to prepare a transparent sol, wherein the molar ratio of tetrabutyl titanate, ethanol, acetylacetone and water is 1:22:0.4:0.4; the glass microspheres and the transparent sol are mixed at a solid-liquid ratio of 1:2.5 and ultrasonically dispersed, and then the solvent is evaporated and removed under stirring, and then the product is calcined at 320°C for 1.5 hours under nitrogen protection to prepare titanium dioxide-coated glass microspheres;

[0066] (2) Perfluorooctyltriethoxysilane was vaporized at 150°C and then deposited on the surface of titanium dioxide-coated glass microspheres. The volume mass ratio of perfluorooctyltriethoxysilane to titanium dioxide-coated glass microspheres was 5 ml:110 g. The modified glass microspheres were then annealed at 130°C under nitrogen conditions to obtain modified glass microspheres.

[0067] The preparation method of the above-mentioned bio-based powder coating having insulating, heat-insulating and anti-fingerprint properties comprises the following steps:

[0068] (1) Mixing a partially modified cardanol-based epoxy resin and dicyandiamide at a mass ratio of 100:5 to prepare a mixture 1;

[0069] (2) mixing the remaining modified cardanol-based epoxy resin and part of the hydroxy polyester resin in a mass ratio of 1:1 to prepare a mixture 2;

[0070] (3) mixing the remaining hydroxy polyester resin and triphenylmethane triisocyanate in a mass ratio of 4:1 to prepare a mixture 3;

[0071] (4) mixing acrylic acid, modified glass microbeads, glass fiber, talc, thermal expansion agent, pigment, leveling agent and benzoin to prepare mixture 4;

[0072] (5) Mixing mixture 1, mixture 2, mixture 3 and mixture 4 to obtain a total mixture;

[0073] (6) The total mixture is heated and extruded. The feed speed of the extruder is 30 rpm, the main machine speed is 50 rpm, and the extrusion temperature is divided into three stages. The heating temperature of the first stage is 95 °C, the heating temperature of the second stage is 105 °C, and the heating temperature of the third stage is 105 °C. Then, the total mixture is cooled, tableted, crushed, ground, and sieved in sequence to obtain a powder coating with a particle size of D50 = 40 μm ± 5 μm. Among them, the tableting speed is 20 rpm, the feed speed during grinding is 25 rpm, the main mill speed is 50 rpm, the auxiliary mill speed is 25 rpm, and the screen mesh size is 200 mesh.

[0074] Example 4

[0075] A bio-based powder coating with insulating, heat-insulating and anti-fingerprint properties comprises the following components in parts by weight: 512 parts of modified cardanol-based epoxy resin, 24 parts of dicyandiamide, 60 parts of hydroxy polyester resin, 7 parts of triphenylmethane triisocyanate, 0.6 parts of acrylic acid, 45 parts of modified glass microbeads, 7 parts of glass fiber, 12 parts of talc, 0.6 parts of thermal expansion agent, 35 parts of pigment, 3 parts of leveling agent, and 1 part of benzoin.

[0076] The modified cardanol-based epoxy resin is prepared by mixing ethanol and water, adjusting the pH value of the mixed solution to 5, adding a silane coupling agent KH560 dropwise thereto, and reacting at 20° C. under stirring for 2 hours to obtain a KH560 hydrolyzate, wherein the mass ratio of KH560, ethanol and water is 8:80:12; the mass ratio of the cardanol-based epoxy resin to KH560 is 100:1.5; then, under nitrogen protection, the cardanol-based epoxy resin is heated to 85° C., and the KH560 hydrolyzate is added dropwise thereto under stirring, the mass ratio of the cardanol-based epoxy resin to the KH560 hydrolyzate is 100:1, and the reaction is stirred for 2 hours. After the reaction is completed, the solvent is removed by rotary evaporation at 60° C. to obtain a modified cardanol-based epoxy resin;

[0077] The preparation method of modified glass microspheres is as follows: (1) in an ice-water bath, ethanol and acetylacetone are mixed, and tetrabutyl titanate is added dropwise thereto, and then an aqueous solution containing aqueous ammonia is added dropwise thereto, and the pH of the mixed solution is adjusted to 4, and stirring is continued to obtain a transparent sol, wherein the molar ratio of tetrabutyl titanate, ethanol, acetylacetone and water is 1:18:0.6:0.4; the glass microspheres and the transparent sol are mixed in a solid-liquid ratio of 1:2 and ultrasonically dispersed, and then the solvent is evaporated and removed under stirring, and then the product is calcined at 320°C for 3 h under nitrogen protection to obtain titanium dioxide-coated glass microspheres;

[0078] (2) Perfluorooctyltriethoxysilane was vaporized at 155°C and then deposited on the surface of titanium dioxide-coated glass microspheres. The volume mass ratio of perfluorooctyltriethoxysilane to titanium dioxide-coated glass microspheres was 5 ml:105 g. The modified glass microspheres were then annealed at 125°C under nitrogen conditions to obtain modified glass microspheres.

[0079] The preparation method of the above-mentioned bio-based powder coating having insulating, heat-insulating and anti-fingerprint properties comprises the following steps:

[0080] (1) Mixing a partially modified cardanol-based epoxy resin and dicyandiamide at a mass ratio of 100:5 to prepare a mixture 1;

[0081] (2) mixing the remaining modified cardanol-based epoxy resin and part of the hydroxy polyester resin in a mass ratio of 1:1 to prepare a mixture 2;

[0082] (3) mixing the remaining hydroxy polyester resin and triphenylmethane triisocyanate in a mass ratio of 4:1 to prepare a mixture 3;

[0083] (4) mixing acrylic acid, modified glass microbeads, glass fiber, talc, thermal expansion agent, pigment, leveling agent and benzoin to prepare mixture 4;

[0084] (5) Mixing mixture 1, mixture 2, mixture 3 and mixture 4 to obtain a total mixture;

[0085] (6) The total mixture is heated and extruded. The feed speed of the extruder is 30 rpm, the main machine speed is 50 rpm, and the extrusion temperature is divided into three stages. The heating temperature of the first stage is 90 °C, the heating temperature of the second stage is 102 °C, and the heating temperature of the third stage is 102 °C. Then, the total mixture is cooled, tableted, crushed, ground, and sieved in sequence to obtain a powder coating with a particle size of D50 = 40 μm ± 5 μm. Among them, the tableting speed is 20 rpm, the feed speed during grinding is 25 rpm, the main mill speed is 50 rpm, the auxiliary mill speed is 25 rpm, and the screen mesh size is 200 mesh.

[0086] Comparative Example 1

[0087] A bio-based powder coating comprises the following components in parts by weight: 476 parts of cardanol-based epoxy resin, 22 parts of dicyandiamide, 60 parts of hydroxy polyester resin, 6 parts of triphenylmethane triisocyanate, 0.5 parts of acrylic acid, 50 parts of glass microbeads, 5 parts of glass fiber, 10 parts of talc, 0.5 parts of thermal expansion agent, 30 parts of pigment, 3 parts of leveling agent, and 1 part of benzoin.

[0088] The preparation method of the above-mentioned bio-based powder coating comprises the following steps:

[0089] (1) Mixing a portion of cardanol-based epoxy resin and dicyandiamide at a mass ratio of 100:5 to prepare a mixture 1;

[0090] (2) mixing the remaining cardanol-based epoxy resin and part of the hydroxy polyester resin in a mass ratio of 1:1 to prepare a mixture 2;

[0091] (3) mixing the remaining hydroxy polyester resin and triphenylmethane triisocyanate in a mass ratio of 4:1 to prepare a mixture 3;

[0092] (4) mixing acrylic acid, glass microbeads, glass fiber, talc, thermal expansion agent, pigment, leveling agent and benzoin to prepare mixture 4;

[0093] (5) Mixing mixture 1, mixture 2, mixture 3 and mixture 4 to obtain a total mixture;

[0094] (6) The total mixture is heated and extruded. The feed speed of the extruder is 30 rpm, the main machine speed is 50 rpm, and the extrusion temperature is divided into three stages. The heating temperature of the first stage is 90 °C, the heating temperature of the second stage is 100 °C, and the heating temperature of the third stage is 100 °C. Then, the mixture is cooled, tableted, crushed, ground, and sieved in sequence to obtain a powder coating with a particle size of D50 = 40 μm ± 5 μm. Among them, the tableting speed is 20 rpm, the feed speed during grinding is 25 rpm, the main mill speed is 50 rpm, the auxiliary mill speed is 25 rpm, and the screen mesh size is 200 mesh.

[0095] Comparative Example 2

[0096] A bio-based powder coating comprises the following components in parts by weight: 476 parts of modified cardanol-based epoxy resin, 22 parts of dicyandiamide, 60 parts of hydroxy polyester resin, 6 parts of triphenylmethane triisocyanate, 0.5 parts of acrylic acid, 50 parts of modified glass microbeads, 5 parts of glass fiber, 10 parts of talc, 0.5 parts of thermal expansion agent, 30 parts of pigment, 3 parts of leveling agent, and 1 part of benzoin.

[0097] The modified cardanol-based epoxy resin is prepared by mixing ethanol and water, adjusting the pH value of the mixed solution to 4, adding a silane coupling agent KH560 dropwise thereto, and reacting at 15° C. under stirring for 2 hours to obtain a KH560 hydrolyzate, wherein the mass ratio of KH560, ethanol, and water is 10:80:10; then, under nitrogen protection, heating the cardanol-based epoxy resin to 80° C., and adding the KH560 hydrolyzate dropwise thereto under stirring, wherein the mass ratio of the cardanol-based epoxy resin to the KH560 hydrolyzate is 100:1.5, stirring and reacting for 2 hours, and after the reaction is completed, rotary evaporation is performed at 60° C. to remove the solvent to obtain a modified cardanol-based epoxy resin;

[0098] The preparation method of modified glass microspheres is as follows: (1) in an ice-water bath, ethanol and acetylacetone are mixed, and tetrabutyl titanate is added dropwise thereto, and then deionized water is added dropwise to prepare a mixed solution, the pH of the mixed solution is adjusted to 4, and stirring is continued to prepare a transparent sol, wherein the molar ratio of tetrabutyl titanate, ethanol, acetylacetone and water is 1:20:0.5:0.3; the glass microspheres and the transparent sol are mixed in a solid-liquid ratio of 1:2 and ultrasonically dispersed, and then the solvent is evaporated and removed under stirring, and then the product is calcined at 300°C for 2h under nitrogen protection to prepare titanium dioxide-coated glass microspheres;

[0099] (2) Perfluorooctyltriethoxysilane was vaporized at 150°C and then deposited on the surface of titanium dioxide-coated glass microspheres. The volume mass ratio of perfluorooctyltriethoxysilane to titanium dioxide-coated glass microspheres was 5 ml:100 g. The modified glass microspheres were then annealed at 120°C in nitrogen to obtain modified glass microspheres.

[0100] The preparation method of the above-mentioned bio-based powder coating comprises the following steps:

[0101] (1) Pour all the raw materials into a mixer and mix for 3 hours to prepare a total mixture;

[0102] (2) The total mixture is heated and extruded. The feed speed of the extruder is 30 rpm, the main machine speed is 50 rpm, and the extrusion temperature is divided into three stages. The heating temperature of the first stage is 90 ° C, the heating temperature of the second stage is 100 ° C, and the heating temperature of the third stage is 100 ° C. Then, it is cooled and tableted, crushed, ground, and sieved in sequence to obtain a powder coating with a particle size of D50 = 40 μm ± 5 μm. Among them, the tableting speed is 20 rpm, the feed speed during grinding is 25 rpm, the main mill speed is 50 rpm, the auxiliary mill speed is 25 rpm, and the screen mesh size is 200 mesh.

[0103] Comparative Example 3

[0104] A bio-based powder coating comprises the following components in parts by weight: 476 parts of modified cardanol-based epoxy resin, 22 parts of dicyandiamide, 60 parts of hydroxy polyester resin, 6 parts of triphenylmethane triisocyanate, 0.5 parts of acrylic acid, 50 parts of modified glass microbeads, 5 parts of glass fiber, 10 parts of talc, 0.5 parts of thermal expansion agent, 30 parts of pigment, 3 parts of leveling agent, and 1 part of benzoin.

[0105] The modified cardanol-based epoxy resin is prepared by mixing ethanol and water, adjusting the pH value of the mixed solution to 4, adding a silane coupling agent KH560 dropwise thereto, and reacting at 15° C. under stirring for 2 hours to obtain a KH560 hydrolyzate, wherein the mass ratio of KH560, ethanol, and water is 10:80:10; then, under nitrogen protection, heating the cardanol-based epoxy resin to 80° C., and adding the KH560 hydrolyzate dropwise thereto under stirring, wherein the mass ratio of the cardanol-based epoxy resin to the KH560 hydrolyzate is 100:1.5, stirring and reacting for 2 hours, and after the reaction is completed, rotary evaporation is performed at 60° C. to remove the solvent to obtain a modified cardanol-based epoxy resin;

[0106] The preparation method of modified glass microspheres is as follows: (1) in an ice-water bath, ethanol and acetylacetone are mixed, and tetrabutyl titanate is added dropwise thereto, and then deionized water is added dropwise to prepare a mixed solution, the pH of the mixed solution is adjusted to 4, and stirring is continued to prepare a transparent sol, wherein the molar ratio of tetrabutyl titanate, ethanol, acetylacetone and water is 1:20:0.5:0.3; the glass microspheres and the transparent sol are mixed in a solid-liquid ratio of 1:2 and ultrasonically dispersed, and then the solvent is evaporated and removed under stirring, and then the product is calcined at 300°C for 2h under nitrogen protection to prepare titanium dioxide-coated glass microspheres;

[0107] (2) Perfluorooctyltriethoxysilane was vaporized at 150°C and then deposited on the surface of titanium dioxide-coated glass microspheres. The volume mass ratio of perfluorooctyltriethoxysilane to titanium dioxide-coated glass microspheres was 5 ml:100 g. The modified glass microspheres were then annealed at 120°C in nitrogen to obtain modified glass microspheres.

[0108] The preparation method of the above-mentioned bio-based powder coating comprises the following steps:

[0109] (1) Mixing a partially modified cardanol-based epoxy resin and dicyandiamide at a mass ratio of 100:5 to prepare a mixture 1;

[0110] (2) mixing the remaining modified cardanol-based epoxy resin and part of the hydroxy polyester resin in a mass ratio of 1:1 to prepare a mixture 2;

[0111] (3) mixing the remaining hydroxy polyester resin and triphenylmethane triisocyanate in a mass ratio of 4:1 to prepare a mixture 3;

[0112] (4) mixing acrylic acid, modified glass microbeads, glass fiber, talc, thermal expansion agent, pigment, leveling agent and benzoin to prepare mixture 4;

[0113] (5) Mixing mixture 1, mixture 2, mixture 3 and mixture 4 to obtain a total mixture;

[0114] (6) The total mixture is heated and extruded, with the feed speed of the extruder being 30 rpm, the main machine speed being 50 rpm, and the extrusion temperature being 120°C; and then subjected to cooling, tableting, crushing, grinding, and sieving operations in sequence to obtain a powder coating with a particle size of D50 = 40 μm ± 5 μm, wherein the tableting speed is 20 rpm, the feed speed during grinding is 25 rpm, the main mill speed is 50 rpm, the auxiliary mill speed is 25 rpm, and the sieve mesh size is 200 mesh.

[0115] The hydroxy polyester resin, thermal expansion agent, pigment, and leveling agent used in the above examples and comparative examples are all the same, and are all commercially available products.

[0116] Test example

[0117] Taking the powder coatings prepared in Example 1 and Comparative Examples 1-3 as examples, the coatings were respectively applied to aluminum plates by electrostatic coating (keeping the spraying parameters consistent) and heated and cured to prepare samples. The insulation, heat insulation, and anti-fingerprint properties of the coatings were then measured. The specific results are shown in Table 1.

[0118] Insulation withstand voltage test: Apply a gradually increasing AC voltage to the surface of the sample, and observe and record the voltage when the coating breaks down;

[0119] Thermal insulation performance test: The coated side of the sample was heated using an infrared heating lamp, and the temperature of the heated side and the back side of the coating was measured. The temperature difference between the two sides was calculated and recorded as △T1. As a control, the uncoated aluminum plate was heated using an infrared heating lamp. The heating temperature and time were the same as above. The temperature difference between the two sides of the aluminum plate was calculated and recorded as △T2. The percentage (%) of the temperature difference between the two sides of the coating ;

[0120] Anti-fingerprint performance: Dip your finger in fingerprint oil (composed of 70% glycerol, 25% water, and 5% urea) and evenly apply it to a circular area with a diameter of approximately 20mm on the coating surface. Let it sit for 10 minutes to simulate the fingerprint drying process. Observe the degree of fingerprint visibility between the coated and uncoated areas.

[0121] Table 1: Test results

[0122]

[0123] The data in the above table show that the powder coating produced by the method in Example 1 has good insulation, heat insulation and anti-fingerprint properties. Compared with Example 1, the modification treatment of the bio-based epoxy resin and glass microspheres was eliminated in Comparative Example 1, the premixing treatment was eliminated in Comparative Example 2, and the staged heating treatment during the heating process was eliminated in Comparative Example 3. The final results show that after the formulation and preparation method were adjusted, the performance of the prepared coating decreased, further proving that the above operations are crucial to the performance of the coating.

[0124] Figure 1 The following are actual demonstrations of the anti-fingerprint effect of the sample in Example 1, where Figures a, b, c, d, and e are taken in chronological order. The results show that after the fingerprint is pressed for the first time, a fingerprint mark can be seen at the edge of the fingerprint on the surface of the sample (Figure a), but after 2 seconds, the fingerprint mark almost disappears, with only a small amount remaining at the lower edge (Figure b). When the fingerprint is pressed for the second time, the fingerprint mark of the first press has completely disappeared (Figure c). When the fingerprint is pressed for the third time, the fingerprint mark of the second press has also completely disappeared (Figure d). 6 seconds after the fingerprint is pressed for the third time, the result shows that all fingerprint marks have disappeared (Figure e). It can be seen that the sample in this application has a good anti-fingerprint effect.

[0125] Figure 2 The following are actual demonstrations of the anti-fingerprint effect of the sample in Comparative Example 1, where Figures a, b, and c are taken in chronological order. The results show that after the fingerprint is pressed for the first time, an obvious fingerprint mark remains on the surface of the sample (Figure a). 9 seconds later, the fingerprint is pressed for the second time, and the fingerprint from the first press is still clearly present, with no sign of disappearing (Figure b). 5 seconds later, the fingerprint is pressed for the third time, and the fingerprints from the first and second presses are still present, with no sign of disappearing (Figure c), proving that the anti-fingerprint effect of the sample in Comparative Example 1 is not obvious, and fingerprints remain after pressing.

[0126] Figure 3 The following are actual demonstrations of the anti-fingerprint effect of the sample in Comparative Example 2. The results show that Figures a, b, and c were taken in chronological order. The results show that after the fingerprint was pressed for the first time, an obvious fingerprint mark remained on the surface of the sample (Figure a). 4 seconds later, the fingerprint was pressed for the second time. At this time, the fingerprint from the first press was still clearly present, with no sign of disappearing (Figure b). 5 seconds later, the fingerprint was pressed for the third time. At this time, the fingerprints from the first and second presses were still present, with no sign of disappearing (Figure c), proving that the anti-fingerprint effect of the sample in Comparative Example 1 was not obvious, and fingerprints remained after pressing.

[0127] Figure 4 The following are actual demonstrations of the anti-fingerprint effect of the sample in Comparative Example 3. The results show that Figures a, b, and c were taken in chronological order. The results show that after the fingerprint was pressed for the first time, an obvious fingerprint mark remained on the surface of the sample (Figure a). 4 seconds later, the fingerprint was pressed for the second time. At this time, the fingerprint from the first press was still clearly present, with no sign of disappearing (Figure b). 4 seconds later, the fingerprint was pressed for the third time. At this time, the fingerprints from the first and second presses were still present, with no sign of disappearing (Figure c), proving that the anti-fingerprint effect of the sample in Comparative Example 1 was not obvious, and fingerprints remained after pressing.

Claims

1. A bio-based powder coating with insulating, heat-insulating and anti-fingerprint properties, characterized in that: The invention comprises the following components in parts by weight: 439-593 parts of modified bio-based epoxy resin, 20-28 parts of dicyandiamide, 55-65 parts of hydroxy polyester resin, 4-8 parts of isocyanate, 0.3-0.8 parts of acrylic acid, 40-60 parts of modified glass microbeads, 3-8 parts of glass fiber, 7-15 parts of talc, 0.3-0.8 parts of thermal expansion agent, 20-40 parts of pigment, 2-4 parts of leveling agent, and 0.5-1.5 parts of benzoin; The modified bio-based epoxy resin is prepared by mixing ethanol and water, adjusting the pH value of the mixed solution to 4-5, adding a silane coupling agent dropwise thereto, and reacting at 4-30° C. under stirring for 1.5-3 hours to obtain a silane coupling agent hydrolyzate; heating the bio-based epoxy resin to 75-85° C. under nitrogen protection, then adding the silane coupling agent hydrolyzate dropwise thereto under stirring, stirring and reacting, and after the reaction is completed, removing the solvent by rotary evaporation to obtain the modified bio-based epoxy resin; The bio-based epoxy resin includes itaconic acid-based epoxy resin and cardanol-based epoxy resin, and the silane coupling agent is KH560; The preparation method of modified glass microspheres is as follows: (1) In an ice-water bath, ethanol and acetylacetone are mixed, and tetrabutyl titanate is added dropwise thereto to prepare a mixed solution, and then an aqueous solution containing aqueous ammonia is added dropwise thereto, and the pH of the mixed solution is adjusted to 3-4, and stirring is continued to prepare a transparent sol; glass microspheres are mixed with the transparent sol and ultrasonically dispersed, and then the solvent is evaporated and removed under stirring, and the product is calcined under nitrogen protection to prepare titanium dioxide-coated glass microspheres; (2) Perfluorooctyltriethoxysilane is vaporized and deposited on the surface of titanium dioxide-coated glass microspheres, and then annealed under nitrogen conditions at 110-130°C to obtain modified glass microspheres; The preparation method of the above coating comprises the following steps: (1) Mixing a partially modified bio-based epoxy resin and dicyandiamide at a mass ratio of 100:5 to prepare a mixture 1; (2) mixing the remaining modified bio-based epoxy resin and part of the hydroxy polyester resin in a mass ratio of 1:1 to prepare mixture 2; (3) mixing the remaining hydroxy polyester resin and isocyanate in a mass ratio of 4:1 to prepare a mixture 3; (4) mixing acrylic acid, modified glass microbeads, glass fiber, talc, thermal expansion agent, pigment, leveling agent and benzoin to prepare mixture 4; (5) Mixing mixture 1, mixture 2, mixture 3 and mixture 4 to obtain a total mixture; (6) The total mixture is subjected to heating extrusion, cooling, tableting, crushing, grinding, and sieving operations in sequence to obtain a powder coating, wherein the heating extrusion temperature is divided into three stages, the first stage heating temperature is 85-95°C, the second stage heating temperature is 96-105°C, and the third stage heating temperature is 96-105°C.

2. The bio-based powder coating with insulation, heat insulation and anti-fingerprint properties according to claim 1, characterized in that: The mass ratio of the silane coupling agent, ethanol and water is 8-12:75-85:8-12; the mass ratio of the bio-based epoxy resin to the silane coupling agent is 100:1-2.

3. The bio-based powder coating with insulation, heat insulation and anti-fingerprint properties according to claim 1, characterized in that: The isocyanate is triphenylmethane triisocyanate.

4. The bio-based powder coating with insulation, heat insulation and anti-fingerprint properties according to claim 1, characterized in that In the step (1) of the preparation method of modified glass microspheres, the molar ratio of tetrabutyl titanate, ethanol, acetylacetone and aqueous solution is 1:18-22:0.4-0.6:0.2-0.4; the solid-liquid ratio of glass microspheres to transparent sol is 1:1.5-2.5; the calcination temperature is 280-320°C, and the calcination time is 1.5-3h.

5. The bio-based powder coating with insulation, heat insulation and anti-fingerprint properties according to claim 1, characterized in that In step (2) of the method for preparing modified glass microspheres, the volume mass ratio of perfluorooctyltriethoxysilane to titanium dioxide-coated glass microspheres is 5 ml:90-110 g; and the vaporization temperature of perfluorooctyltriethoxysilane is 140-160°C.

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