Low-temperature curing powder coating and preparation method thereof

Abstract

The invention relates to the technical field of coatings, and provides a low-temperature curing powder coating and a preparation method thereof. The low-temperature curing powder coating is prepared from the following raw materials in parts by weight: 65-75 parts of epoxy resin, 4-6 parts of a low-temperature curing agent, 4-6 parts of modified titanium dioxide, 6-8 parts of manganese dioxide composite silicon carbide, 0.4-0.6 part of a curing accelerator, 1.6-2 parts of a flatting agent and 0.4-0.6 part of an antioxidant. The prepared powder coating has excellent adhesive force, the curing time can be effectively shortened in the using process of the coating, and the production efficiency is improved.

Description

Technical Field

[0001] The present invention relates to the technical field of coatings, and in particular to a low-temperature curing powder coating and a preparation method thereof. Background Art

[0002] Powder coating is a thermosetting coating with excellent environmental performance and physical and mechanical properties, and is widely used in the coating of various materials. Traditional powder coatings have a high curing temperature, usually between 180℃-200℃, which not only consumes a lot of energy, but also limits its application on heat-sensitive materials. With the increasing awareness of energy conservation and emission reduction and the improvement of environmental protection requirements, low-temperature curing powder coatings have gradually become a research hotspot.

[0003] Low temperature curing powder coating refers to thermosetting powder coating with low curing temperature, and its curing conditions are generally 120℃-2 hours or 130℃-1 hour. The coating prepared by this type of coating has high mechanical strength, excellent moisture resistance and chemical corrosion resistance.

[0004] Although low temperature curing powder coatings have many advantages, the existing low temperature curing powder coating technology still has some shortcomings. Some low temperature curing powder coatings have a long curing time, which affects the production efficiency. Some low temperature curing powder coatings have poor performance in terms of gloss, leveling and adhesion of the cured coating film, and cannot meet the requirements of high-end decoration. In view of the above problems, the present invention proposes a new type of low temperature curing powder coating and a preparation method thereof. Summary of the invention

[0005] The present invention provides a low-temperature curing powder coating and a preparation method thereof, which solves the problems of long curing time and poor coating performance of the low-temperature curing powder coating, improves production efficiency, and the prepared powder coating also has excellent adhesion.

[0006] The technical solution of the present invention is as follows: In the first aspect, the present invention proposes a low-temperature curing powder coating, which is composed of the following raw materials in parts by weight: 65-75 parts of epoxy resin, 4-6 parts of low-temperature curing agent, 4-6 parts of modified titanium dioxide, 6-8 parts of manganese dioxide composite silicon carbide, 0.4-0.6 parts of curing accelerator, 1.6-2 parts of leveling agent, and 0.4-0.6 parts of antioxidant.

[0007] As a further technical solution, the curing temperature of the low-temperature curing powder coating is 100-120° C., and the curing time is 30-40 minutes.

[0008] As a further technical solution, the preparation method of the modified titanium dioxide comprises: adding titanium dioxide and sodium dodecyl sulfate into water and mixing them evenly, maintaining them under vacuum conditions for 60-80 minutes, and then drying them at 70-90° C. for 23-25 ​​hours.

[0009] As a further technical solution, the usage ratio of titanium dioxide, sodium dodecyl sulfate and water is 0.4-0.6g:2-3g:100mL.

[0010] As a further technical solution, the preparation method of manganese dioxide composite silicon carbide includes: adding potassium permanganate to deionized water and mixing and stirring to obtain a potassium permanganate solution, then adding silicon carbide, continuing to stir, subjecting the obtained mixed solution to a hydrothermal reaction, and obtaining manganese dioxide composite silicon carbide after filtering, washing, and drying.

[0011] As a further technical solution, the usage ratio of potassium permanganate, deionized water and silicon carbide is 0.03-0.05g:75-85mL:0.2-0.3g.

[0012] As a further technical solution, the temperature of the hydrothermal reaction is 150-160° C., and the time of the hydrothermal reaction is 60-80 min.

[0013] As a further technical solution, the low-temperature curing agent is low-temperature curing agent YH-82, the curing accelerator is curing accelerator DMP-30, the leveling agent is leveling agent BYK-333, and the antioxidant is antioxidant 1010.

[0014] In a second aspect, the present invention provides a method for preparing a low temperature curing powder coating, the steps comprising: (1) The raw materials of the low-temperature curing powder coating are mixed uniformly, and the mixed material is fed into a twin-screw extruder for melt extrusion, and then subjected to twin-roll sheeting to obtain a sheet material; (2) The flaky material is cooled, crushed, ground and passed through a 100-mesh sieve to obtain a powder coating.

[0015] As a further technical solution, the temperature of each zone of the twin-screw extruder is set as follows: the temperature of zone 1 is 95-105°C, and the temperature of zone 2 is 100-110°C.

[0016] The working principle and beneficial effects of the present invention are: The present invention obtains modified titanium dioxide by mixing titanium dioxide and sodium dodecyl sulfate in water and keeping the mixture under vacuum for a period of time, utilizing the effect of the surfactant sodium dodecyl sulfate to improve the dispersibility and surface properties of titanium dioxide, and then performing a drying treatment. The surfactant can reduce the surface tension between titanium dioxide particles, making it easier to disperse evenly in water and avoiding the occurrence of agglomeration, which helps to improve the dispersibility of titanium dioxide in the coating, thereby enhancing the hiding power and gloss of the coating; the modified titanium dioxide has enhanced compatibility with the resin and can be better integrated into the resin matrix, which helps to better disperse and stabilize the titanium dioxide particles in the resin, forming a tighter coating structure. This helps to improve the density and adhesion of the coating; in addition, the addition of modified titanium dioxide further promotes the cross-linking reaction between the resin and the curing agent, thereby shortening the curing time; The present invention uses a hydrothermal reaction between potassium manganate and silicon carbide, whereby potassium permanganate is reduced to manganese dioxide and deposited on the surface of silicon carbide to form a composite material; during the hydrothermal reaction, potassium permanganate is reduced to manganese dioxide and deposited on the surface of silicon carbide. This composite material combines the oxidizability of manganese dioxide and the hardness of silicon carbide, which not only improves wear resistance, but also acts as a catalyst to accelerate chemical reactions in the coating to a certain extent, effectively reducing the curing temperature and shortening the curing time; In the present invention, the modified titanium dioxide and manganese dioxide composite silicon carbide play a synergistic role in the coating. The modified titanium dioxide can be used as a photocatalyst or reaction accelerator to promote the curing reaction in the coating at a lower temperature. By reducing the activation energy or providing the active sites required for the reaction, the modified titanium dioxide helps to achieve rapid curing of the coating at a lower temperature. After the manganese dioxide and silicon carbide are composited, they have a certain catalytic and promoting effect on the chemical reaction of the coating, which helps to shorten the curing time and reduce the curing temperature. DETAILED DESCRIPTION

[0017] The following will be combined with the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0018] It should be noted that the model of the epoxy resin in the present invention is epoxy resin E-51.

[0019] Example 1 In this embodiment, a low-temperature curing powder coating is provided, which is composed of the following raw materials in parts by weight: 70 parts of epoxy resin, 5 parts of low-temperature curing agent, 5 parts of modified titanium dioxide, 7 parts of manganese dioxide composite silicon carbide, 0.5 parts of curing accelerator, 1.8 parts of leveling agent, and 0.5 parts of antioxidant; the curing temperature of the low-temperature curing powder coating is 100°C, and the curing time is 30 minutes; The preparation method of modified titanium dioxide includes: adding titanium dioxide and sodium dodecyl sulfate into water and mixing them evenly, keeping them under vacuum for 70 minutes, and then drying them at 80°C for 24 hours; the amount ratio of titanium dioxide, sodium dodecyl sulfate and water is 0.5g:2.5g:100mL; The preparation method of manganese dioxide composite silicon carbide includes: adding potassium permanganate to deionized water and mixing and stirring to obtain a potassium permanganate solution, then adding silicon carbide, continuing to stir, subjecting the obtained mixed solution to a hydrothermal reaction at a temperature of 155° C. for 70 minutes, filtering, deionizing and washing three times, and drying at 60° C. to obtain manganese dioxide composite silicon carbide; the dosage ratio of potassium permanganate, deionized water and silicon carbide is 0.04 g: 80 mL: 0.25 g; Among them, the low temperature curing agent is low temperature curing agent YH-82, the curing accelerator is curing accelerator DMP-30, the leveling agent is leveling agent BYK-333, and the antioxidant is antioxidant 1010; The preparation method of the low temperature curing powder coating comprises the following steps: (1) The raw materials of the low-temperature curing powder coating are mixed uniformly, and the mixed material is fed into a twin-screw extruder for melt extrusion, and a sheet material is obtained through a twin-roll sheeting process; the temperature of each zone of the twin-screw extruder is set as follows: the temperature of the first zone is 100°C, and the temperature of the second zone is 105°C.

[0020] (2) Cool, crush, grind and sieve the flaky material through a 100-mesh sieve to obtain a powder coating.

[0021] Example 2 The present embodiment provides a low-temperature curing powder coating, which is composed of the following raw materials in parts by weight: 65 parts of epoxy resin, 4 parts of low-temperature curing agent, 6 parts of modified titanium dioxide, 6 parts of manganese dioxide composite silicon carbide, 0.4 parts of curing accelerator, 2 parts of leveling agent, and 0.4 parts of antioxidant; the curing temperature of the low-temperature curing powder coating is 108°C, and the curing time is 34 minutes; The preparation method of modified titanium dioxide includes: adding titanium dioxide and sodium dodecyl sulfate into water and mixing them evenly, keeping them under vacuum for 80 minutes, and then drying them at 70°C for 25 hours; the amount ratio of titanium dioxide, sodium dodecyl sulfate and water is 0.4g:3g:100mL; The preparation method of manganese dioxide composite silicon carbide includes: adding potassium permanganate to deionized water and mixing and stirring to obtain a potassium permanganate solution, then adding silicon carbide, continuing to stir, subjecting the obtained mixed solution to a hydrothermal reaction at a temperature of 150° C. for 80 minutes, filtering, deionizing and washing three times, and drying at 60° C. to obtain manganese dioxide composite silicon carbide; the dosage ratio of potassium permanganate, deionized water and silicon carbide is 0.03 g: 85 mL: 0.2 g; Among them, the low temperature curing agent is low temperature curing agent YH-82, the curing accelerator is curing accelerator DMP-30, the leveling agent is leveling agent BYK-333, and the antioxidant is antioxidant 1010; The preparation method of the low temperature curing powder coating comprises the following steps: (1) The raw materials of the low-temperature curing powder coating are mixed uniformly, and the mixed material is fed into a twin-screw extruder for melt extrusion, and a sheet material is obtained through a twin-roll sheeting process; the temperature of each zone of the twin-screw extruder is set as follows: the temperature of the first zone is 95°C, and the temperature of the second zone is 100°C.

[0022] (2) Cool, crush, grind and sieve the flaky material through a 100-mesh sieve to obtain a powder coating.

[0023] Example 3 The present embodiment provides a low-temperature curing powder coating, which is composed of the following raw materials in parts by weight: 72 parts of epoxy resin, 6 parts of low-temperature curing agent, 4 parts of modified titanium dioxide, 8 parts of manganese dioxide composite silicon carbide, 0.6 parts of curing accelerator, 1.6 parts of leveling agent, and 0.6 parts of antioxidant; the curing temperature of the low-temperature curing powder coating is 112°C, and the curing time is 36 minutes; The preparation method of modified titanium dioxide includes: adding titanium dioxide and sodium dodecyl sulfate into water and mixing them evenly, keeping them under vacuum for 80 minutes, and then drying them at 80°C for 23 hours; the amount ratio of titanium dioxide, sodium dodecyl sulfate and water is 0.5g:2g:100mL; The preparation method of manganese dioxide composite silicon carbide includes: adding potassium permanganate to deionized water and mixing and stirring to obtain a potassium permanganate solution, then adding silicon carbide, continuing to stir, subjecting the obtained mixed solution to a hydrothermal reaction at a temperature of 150° C. for 80 minutes, filtering, deionizing and washing three times, and drying at 60° C. to obtain manganese dioxide composite silicon carbide; the dosage ratio of potassium permanganate, deionized water and silicon carbide is 0.04 g: 83 mL: 0.24 g; Among them, the low temperature curing agent is low temperature curing agent YH-82, the curing accelerator is curing accelerator DMP-30, the leveling agent is leveling agent BYK-333, and the antioxidant is antioxidant 1010; The preparation method of the low temperature curing powder coating comprises the following steps: (1) The raw materials of the low-temperature curing powder coating are mixed uniformly, and the mixed material is fed into a twin-screw extruder for melt extrusion, and then subjected to twin-roll sheeting to obtain a sheet material; the temperature of each zone of the twin-screw extruder is set as follows: the temperature of the first zone is 105° C., and the temperature of the second zone is 110° C.

[0024] (2) Cool, crush, grind and sieve the flaky material through a 100-mesh sieve to obtain a powder coating.

[0025] Example 4 In this embodiment, a low-temperature curing powder coating is provided, which is composed of the following raw materials in parts by weight: 75 parts of epoxy resin, 4 parts of low-temperature curing agent, 6 parts of modified titanium dioxide, 6 parts of manganese dioxide composite silicon carbide, 0.6 parts of curing accelerator, 1.6 parts of leveling agent, and 0.5 parts of antioxidant; the curing temperature of the low-temperature curing powder coating is 117°C, and the curing time is 38 minutes; The preparation method of modified titanium dioxide includes: adding titanium dioxide and sodium dodecyl sulfate into water and mixing them evenly, keeping them under vacuum for 70 minutes, and then drying them at 90°C for 23 hours; the amount ratio of titanium dioxide, sodium dodecyl sulfate and water is 0.6g:2g:100mL; The preparation method of manganese dioxide composite silicon carbide includes: adding potassium permanganate to deionized water and mixing and stirring to obtain a potassium permanganate solution, then adding silicon carbide, continuing to stir, subjecting the obtained mixed solution to a hydrothermal reaction at a temperature of 160° C. for 80 minutes, filtering, deionizing and washing three times, and drying at 60° C. to obtain manganese dioxide composite silicon carbide; the dosage ratio of potassium permanganate, deionized water and silicon carbide is 0.05 g:85 mL:0.3 g; Among them, the low temperature curing agent is low temperature curing agent YH-82, the curing accelerator is curing accelerator DMP-30, the leveling agent is leveling agent BYK-333, and the antioxidant is antioxidant 1010; The preparation method of the low temperature curing powder coating comprises the following steps: (1) The raw materials of the low-temperature curing powder coating are mixed uniformly, and the mixed material is fed into a twin-screw extruder for melt extrusion, and then subjected to twin-roll sheeting to obtain a sheet material; the temperature of each zone of the twin-screw extruder is set as follows: the temperature of zone 1 is 100° C., and the temperature of zone 2 is 110° C.

[0026] (2) Cool, crush, grind and sieve the flaky material through a 100-mesh sieve to obtain a powder coating.

[0027] Comparative Example 1 In this comparative example, a low-temperature curing powder coating is provided, which is composed of the following raw materials in parts by weight: 70 parts of epoxy resin, 5 parts of low-temperature curing agent, 5 parts of modified titanium dioxide, 7 parts of manganese dioxide composite silicon carbide, 0.5 parts of curing accelerator, 1.8 parts of leveling agent, and 0.5 parts of antioxidant; the curing temperature of the low-temperature curing powder coating is 100°C, and the curing time is 30 minutes; The preparation method of modified titanium dioxide comprises: adding titanium dioxide and sodium dodecylbenzene sulfonate into water and mixing them evenly, keeping them under vacuum for 70 minutes, and then drying them at 80° C. for 24 hours; the amount ratio of titanium dioxide, sodium dodecylbenzene sulfonate and water is 0.5 g: 2.5 g: 100 mL; The preparation method of manganese dioxide composite silicon carbide includes: adding potassium permanganate to deionized water and mixing and stirring to obtain a potassium permanganate solution, then adding silicon carbide, continuing to stir, subjecting the obtained mixed solution to a hydrothermal reaction at a temperature of 155° C. for 70 minutes, filtering, deionizing and washing three times, and drying at 60° C. to obtain manganese dioxide composite silicon carbide; the dosage ratio of potassium permanganate, deionized water and silicon carbide is 0.04 g: 80 mL: 0.25 g; Among them, the low temperature curing agent is low temperature curing agent YH-82, the curing accelerator is curing accelerator DMP-30, the leveling agent is leveling agent BYK-333, and the antioxidant is antioxidant 1010; The preparation method of the low temperature curing powder coating comprises the following steps: (1) The raw materials of the low-temperature curing powder coating are mixed uniformly, and the mixed material is fed into a twin-screw extruder for melt extrusion, and then subjected to twin-roll sheeting to obtain a sheet material; the temperature of each zone of the twin-screw extruder is set as follows: the temperature of zone 1 is 100° C., and the temperature of zone 2 is 105° C.

[0028] (2) Cool, crush, grind and sieve the flaky material through a 100-mesh sieve to obtain a powder coating.

[0029] Comparative Example 2 In this comparative example, a low-temperature curing powder coating is provided, which is composed of the following raw materials in parts by weight: 70 parts of epoxy resin, 5 parts of low-temperature curing agent, 5 parts of titanium dioxide, 7 parts of manganese dioxide composite silicon carbide, 0.5 parts of curing accelerator, 1.8 parts of leveling agent, and 0.5 parts of antioxidant; the curing temperature of the low-temperature curing powder coating is 100°C, and the curing time is 30 minutes; The preparation method of manganese dioxide composite silicon carbide includes: adding potassium permanganate to deionized water and mixing and stirring to obtain a potassium permanganate solution, then adding silicon carbide, continuing to stir, subjecting the obtained mixed solution to a hydrothermal reaction at a temperature of 155° C. for 70 minutes, filtering, deionizing and washing three times, and drying at 60° C. to obtain manganese dioxide composite silicon carbide; the dosage ratio of potassium permanganate, deionized water and silicon carbide is 0.04 g: 80 mL: 0.25 g; Among them, the low temperature curing agent is low temperature curing agent YH-82, the curing accelerator is curing accelerator DMP-30, the leveling agent is leveling agent BYK-333, and the antioxidant is antioxidant 1010; The preparation method of the low temperature curing powder coating comprises the following steps: (1) The raw materials of the low-temperature curing powder coating are mixed uniformly, and the mixed material is fed into a twin-screw extruder for melt extrusion, and then subjected to twin-roll sheeting to obtain a sheet material; the temperature of each zone of the twin-screw extruder is set as follows: the temperature of zone 1 is 100° C., and the temperature of zone 2 is 105° C.

[0030] (2) Cool, crush, grind and sieve the flaky material through a 100-mesh sieve to obtain a powder coating.

[0031] Comparative Example 3 In this comparative example, a low-temperature curing powder coating is provided, which is composed of the following raw materials in parts by weight: 70 parts of epoxy resin, 5 parts of low-temperature curing agent, 7 parts of manganese dioxide composite silicon carbide, 0.5 parts of curing accelerator, 1.8 parts of leveling agent, and 0.5 parts of antioxidant; the curing temperature of the low-temperature curing powder coating is 100°C, and the curing time is 30 minutes; The preparation method of manganese dioxide composite silicon carbide includes: adding potassium permanganate to deionized water and mixing and stirring to obtain a potassium permanganate solution, then adding silicon carbide, continuing to stir, subjecting the obtained mixed solution to a hydrothermal reaction at a temperature of 155° C. for 70 minutes, filtering, deionizing and washing three times, and drying at 60° C. to obtain manganese dioxide composite silicon carbide; the dosage ratio of potassium permanganate, deionized water and silicon carbide is 0.04 g: 80 mL: 0.25 g; Among them, the low temperature curing agent is low temperature curing agent YH-82, the curing accelerator is curing accelerator DMP-30, the leveling agent is leveling agent BYK-333, and the antioxidant is antioxidant 1010; The preparation method of the low temperature curing powder coating comprises the following steps: (1) The raw materials of the low-temperature curing powder coating are mixed uniformly, and the mixed material is fed into a twin-screw extruder for melt extrusion, and then subjected to twin-roll sheeting to obtain a sheet material; the temperature of each zone of the twin-screw extruder is set as follows: the temperature of zone 1 is 100° C., and the temperature of zone 2 is 105° C.

[0032] (2) Cool, crush, grind and sieve the flaky material through a 100-mesh sieve to obtain a powder coating.

[0033] Comparative Example 4 In this comparative example, a low-temperature curing powder coating is provided, which is composed of the following raw materials in parts by weight: 70 parts of epoxy resin, 5 parts of low-temperature curing agent, 5 parts of modified titanium dioxide, 7 parts of manganese dioxide composite silicon dioxide, 0.5 parts of curing accelerator, 1.8 parts of leveling agent, and 0.5 parts of antioxidant; the curing temperature of the low-temperature curing powder coating is 100°C, and the curing time is 30 minutes; The preparation method of modified titanium dioxide includes: adding titanium dioxide and sodium dodecyl sulfate into water and mixing them evenly, keeping them under vacuum for 70 minutes, and then drying them at 80°C for 24 hours; the amount ratio of titanium dioxide, sodium dodecyl sulfate and water is 0.5g:2.5g:100mL; The preparation method of manganese dioxide composite silicon dioxide comprises: adding potassium permanganate to deionized water and mixing and stirring to obtain a potassium permanganate solution, then adding silicon dioxide, continuing to stir, subjecting the obtained mixed solution to a hydrothermal reaction at a temperature of 155° C. for 70 minutes, filtering, deionizing washing 3 times, and drying at 60° C. to obtain manganese dioxide composite silicon dioxide; the dosage ratio of potassium permanganate, deionized water and silicon dioxide is 0.04 g: 80 mL: 0.25 g; Among them, the low temperature curing agent is low temperature curing agent YH-82, the curing accelerator is curing accelerator DMP-30, the leveling agent is leveling agent BYK-333, and the antioxidant is antioxidant 1010; The preparation method of the low temperature curing powder coating comprises the following steps: (1) The raw materials of the low-temperature curing powder coating are mixed uniformly, and the mixed material is fed into a twin-screw extruder for melt extrusion, and then subjected to twin-roll sheeting to obtain a sheet material; the temperature of each zone of the twin-screw extruder is set as follows: the temperature of zone 1 is 100° C., and the temperature of zone 2 is 105° C.

[0034] (2) Cool, crush, grind and sieve the flaky material through a 100-mesh sieve to obtain a powder coating.

[0035] Comparative Example 5 In this comparative example, a low-temperature curing powder coating is provided, which is composed of the following raw materials in parts by weight: 70 parts of epoxy resin, 5 parts of low-temperature curing agent, 5 parts of modified titanium dioxide, 7 parts of silicon carbide, 0.5 parts of curing accelerator, 1.8 parts of leveling agent, and 0.5 parts of antioxidant; the curing temperature of the low-temperature curing powder coating is 100°C, and the curing time is 30 minutes; The preparation method of modified titanium dioxide includes: adding titanium dioxide and sodium dodecyl sulfate into water and mixing them evenly, keeping them under vacuum for 70 minutes, and then drying them at 80°C for 24 hours; the amount ratio of titanium dioxide, sodium dodecyl sulfate and water is 0.5g:2.5g:100mL; Among them, the low temperature curing agent is low temperature curing agent YH-82, the curing accelerator is curing accelerator DMP-30, the leveling agent is leveling agent BYK-333, and the antioxidant is antioxidant 1010; The preparation method of the low temperature curing powder coating comprises the following steps: (1) The raw materials of the low-temperature curing powder coating are mixed uniformly, and the mixed material is fed into a twin-screw extruder for melt extrusion, and then subjected to twin-roll sheeting to obtain a sheet material; the temperature of each zone of the twin-screw extruder is set as follows: the temperature of zone 1 is 100° C., and the temperature of zone 2 is 105° C.

[0036] (2) Cool, crush, grind and sieve the flaky material through a 100-mesh sieve to obtain a powder coating.

[0037] Comparative Example 6 In this comparative example, a low-temperature curing powder coating is provided, which is composed of the following raw materials in parts by weight: 70 parts of epoxy resin, 5 parts of low-temperature curing agent, 5 parts of modified titanium dioxide, 0.5 parts of curing accelerator, 1.8 parts of leveling agent, and 0.5 parts of antioxidant; the curing temperature of the low-temperature curing powder coating is 100°C, and the curing time is 30 minutes; The preparation method of modified titanium dioxide includes: adding titanium dioxide and sodium dodecyl sulfate into water and mixing them evenly, keeping them under vacuum for 70 minutes, and then drying them at 80°C for 24 hours; the amount ratio of titanium dioxide, sodium dodecyl sulfate and water is 0.5g:2.5g:100mL; Among them, the low temperature curing agent is low temperature curing agent YH-82, the curing accelerator is curing accelerator DMP-30, the leveling agent is leveling agent BYK-333, and the antioxidant is antioxidant 1010; The preparation method of the low temperature curing powder coating comprises the following steps: (1) The raw materials of the low-temperature curing powder coating are mixed uniformly, and the mixed material is fed into a twin-screw extruder for melt extrusion, and then subjected to twin-roll sheeting to obtain a sheet material; the temperature of each zone of the twin-screw extruder is set as follows: the temperature of zone 1 is 100° C., and the temperature of zone 2 is 105° C.

[0038] (2) Cool, crush, grind and sieve the flaky material through a 100-mesh sieve to obtain a powder coating.

[0039] Test Example 1: The powder coatings prepared in the above-mentioned Examples 1-4 and Comparative Examples 1-6 were sprayed on 50 mm × 50 mm aluminum sheets by high-voltage electrostatic spraying, and the coating thickness was 80 μm to prepare the test samples, and the performance was explored. The prepared powder coatings were tested as follows: 1. In the process of preparing samples, the curing temperature and curing time of each sample are counted; 2. Wear resistance test: GB / T 23988-2009 "Falling sand method for determination of wear resistance of coatings" was used, and the test was conducted three times in parallel to obtain the average value. The larger the test value, the more falling sand is required for unit coating wear, indicating that the wear resistance of the coating is better; 3. Adhesion test: It is carried out in accordance with GB / T 9286-2021 "Scratch test for paint and varnish films". The smaller the number, the better the adhesion.

[0040] The test results are shown in Table 1 below: Table 1

[0041] The above are only preferred embodiments of the present invention and are not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention should be included in the protection scope of the present invention.

Claims

1. A low temperature curing powder coating, characterized in that: The invention is composed of the following raw materials in parts by weight: 65-75 parts of epoxy resin, 4-6 parts of low-temperature curing agent, 4-6 parts of modified titanium dioxide, 6-8 parts of manganese dioxide composite silicon carbide, 0.4-0.6 parts of curing accelerator, 1.6-2 parts of leveling agent and 0.4-0.6 parts of antioxidant.

2. A low temperature curing powder coating according to claim 1, characterized in that: The curing temperature of the low-temperature curing powder coating is 100-120° C., and the curing time is 30-40 minutes.

3. A low temperature curing powder coating according to claim 2, characterized in that: The preparation method of the modified titanium dioxide comprises: adding titanium dioxide and sodium dodecyl sulfate into water and mixing them evenly, maintaining the mixture under vacuum for 60-80 minutes, and then drying the mixture at 70-90° C. for 23-25 ​​hours.

4. A low temperature curing powder coating according to claim 3, characterized in that: The dosage ratio of the titanium dioxide, sodium lauryl sulfate and water is 0.4-0.6 g: 2-3 g: 100 mL.

5. A low temperature curing powder coating according to claim 1, characterized in that: The preparation method of manganese dioxide composite silicon carbide comprises: adding potassium permanganate into deionized water, mixing and stirring to obtain a potassium permanganate solution, then adding silicon carbide, continuing to stir, subjecting the obtained mixed solution to a hydrothermal reaction, and filtering, washing and drying to obtain the manganese dioxide composite silicon carbide.

6. A low temperature curing powder coating according to claim 5, characterized in that: The dosage ratio of the potassium permanganate, deionized water and silicon carbide is 0.03-0.05 g: 75-85 mL: 0.2-0.3 g.

7. A low temperature curing powder coating according to claim 5, characterized in that: The temperature of the hydrothermal reaction is 150-160° C., and the time of the hydrothermal reaction is 60-80 minutes.

8. A low temperature curing powder coating according to claim 1, characterized in that: The low-temperature curing agent is low-temperature curing agent YH-82, the curing accelerator is curing accelerator DMP-30, the leveling agent is leveling agent BYK-333, and the antioxidant is antioxidant 1010.

9. The method for preparing a low temperature curing powder coating according to any one of claims 1 to 8, characterized in that the steps include: S1, mixing the raw materials of the low-temperature curing powder coating uniformly, and feeding the mixed material into a twin-screw extruder for melt extrusion, and pressing the mixed material through a twin-roller to obtain a sheet material; S2. Cooling, crushing, grinding and passing the flaky material through a 100-mesh sieve to obtain a powder coating.

10. The method for preparing a low temperature curing powder coating according to claim 9, characterized in that: The temperature of each zone of the twin-screw extruder is set as follows: the temperature of zone 1 is 95-105°C, and the temperature of zone 2 is 100-110°C.

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