A bio-based low temperature curing powder coating and a method for its preparation

Abstract

The application provides a kind of bio-based low temperature curing powder coating and its preparation method, belong to powder coating technical field, specifically including the following weight parts of components: bio-based resin 65-75 parts, trisglycidyl isocyanurate 5-6 parts, tetrabutylammonium bromide 0.05-0.15 parts, air glass microsphere 8-12 parts, mica 4-6 parts, ethylene bis-stearamide 0.4-0.6 parts, leveling agent 0.7-1.3 parts, benzoin 0.2-0.5 parts, amide wax 0.3-0.7 parts and pigment 6-8 parts.The bio-based low temperature curing powder coating curing temperature is 100-120 DEG C, has the advantage of low curing temperature, can be suitable for plastic device surface coating, and the powder coating has the advantages of salt spray resistance, impact resistance, etc., can effectively solve the existing problems of powder coating.

Description

TECHNICAL FIELD

[0001] The present application belongs to the technical field of powder coatings, and particularly relates to a bio-based low-temperature curing powder coating and a preparation method thereof. BACKGROUND

[0002] Low-temperature curing powder coating generally refers to a powder coating technology with a curing temperature between 140 DEG C and 160 DEG C, or even lower (such as 120 DEG C). It is one of the most important technical development directions in the powder coating industry, aiming to break through the limitation of traditional powder coating which requires high temperature curing at 180-200 DEG C, so as to expand its application field and enhance its competitiveness.

[0003] However, the existing low-temperature curing powder coating has the following problems:

[0004] Poor storage stability: the higher the reactivity of the powder, the poorer the storage stability at room temperature, and the easier the caking;

[0005] Balancing the mechanical properties and the degree of reaction is difficult: at low temperature, it is necessary to ensure that the crosslinking reaction can proceed fully, otherwise the hardness, chemical resistance and impact resistance of the coating will be affected;

[0006] High cost: high-performance low-temperature curing resins, curing agents and catalysts usually have higher cost;

[0007] Narrow process window: the curing temperature and time window of the low-temperature curing system may be narrower, and the control requirements for the construction process are more stringent.

[0008] Moreover, due to the high curing temperature of the existing coating and the low tolerance temperature of plastic devices, the existing coating can only be applied to the surface of metal materials and cannot be applied to the surface of plastic devices, so it is particularly important to develop a powder coating that can be applied to plastic devices. SUMMARY

[0009] In view of the above problems in the prior art, the present application provides a bio-based low-temperature curing powder coating and a preparation method thereof. The bio-based low-temperature curing powder coating has a curing temperature of 100-120 DEG C, has the advantage of low curing temperature, can be applied to the surface of plastic devices, and has the advantages of salt spray resistance, impact resistance, etc., which can effectively solve the problems of the existing powder coating.

[0010] To achieve the above-mentioned purposes, the technical scheme adopted by the present application to solve its technical problems is:

[0011] A bio-based low-temperature curing powder coating, comprising the following components by weight: bio-based resin 65-75 parts, trisglycidyl isocyanurate 5-6 parts, tetrabutylammonium bromide 0.05-0.15 parts, air glass microbeads 8-12 parts, mica 4-6 parts, ethylene bis-stearamide 0.4-0.6 parts, leveling agent 0.7-1.3 parts, benzoin 0.2-0.5 parts, amide wax 0.3-0.7 parts and pigment 6-8 parts;

[0012] The bio-based resin is made of the following components by weight: neopentyl glycol 1000-1200 parts, 2,5-furan dicarboxylic acid 1400-1700 parts, trimethylolpropane 10-16 parts, catalyst (butyl tin oxide) 1-3.5 parts, isophthalic acid 180-220 parts, adipic acid 35-55 parts, antioxidant 5-9 parts and resin stabilizer 5-9 parts.

[0013] Further, the following components by weight are included: bio-based resin 70 parts, trisglycidyl isocyanurate 5.3 parts, tetrabutylammonium bromide 0.1 parts, air glass microbeads 10 parts, mica 5 parts, ethylene bis-stearamide 0.5 parts, leveling agent 1 part, benzoin 0.3 parts, amide wax 0.5 parts and pigment 7.3 parts.

[0014] Further, the catalyst is butyl tin oxide; the antioxidant is β-(3,5-di-tert-butyl-4-hydroxyphenyl) octadecyl propionate, and the resin stabilizer is triphenylphosphine.

[0015] Further, the bio-based resin is prepared by the following method:

[0016] (1) neopentyl glycol and trimethylolpropane are added to a reaction kettle with stirring speed of 30 Hz, heated to melt the materials, then 2,5-furan dicarboxylic acid and catalyst are sequentially added, nitrogen is introduced for protection, and the temperature is further raised to 235-245℃, when the temperature reaches 85-95℃, 30% antioxidant is added, and the reaction is kept until the acid value is 12-14 mgKOH / g;

[0017] (2) the material is cooled to 225-235℃, the stirring is turned off, then isophthalic acid and adipic acid are added, and the stirring speed is set to 70 Hz, and stirring is performed until the materials are uniformly mixed;

[0018] (3) the material is continuously heated to 235-245℃, and the reaction is kept until the acid value of the material reaches 50-55 mgKOH / g, and the viscosity reaches 600-1000 mPa.s;

[0019] (4) Continue to invest 30% of the antioxidant, stirring and mixing, start vacuumizing, vacuumizing to 0.09Mpa or above within 30min, continue to react under vacuum, take sample every 10-15min until the acid value reaches 40-45mgKOH / g and the viscosity is 900-1200mPa.s / 200℃;

[0020] (5) The material is cooled to 210-220℃, the stirring speed is adjusted to 50Hz, the remaining 40% antioxidant and triphenylphosphine are added, the stirring speed is adjusted to 70Hz after the addition is completed, and the stirring is continued for 40min to prepare the bio-based resin.

[0021] Further, in step (1), the temperature is raised to 240℃, and the antioxidant is added when the temperature is 90℃.

[0022] Further, in step (2), the material is cooled to 230℃.

[0023] Further, in step (3), the temperature is raised to 240℃.

[0024] Further, in step (5), the temperature is raised to 215℃.

[0025] The preparation method of the above-mentioned bio-based low-temperature curing powder coating mixes all raw materials at high speed, melts and disperses, extrudes, cools, breaks into pieces, grinds to a particle size of 25-35μm, and prepares. The beneficial effects of the present application are:

[0026] 1. In the present application, 2,5-furandicarboxylic acid is used as the core bio-based raw material, which is used to build a polyol system with neopentyl glycol and trimethylolpropane. The rigid furan ring structure of 2,5-furandicarboxylic acid can endow the resin material with excellent heat resistance and mechanical strength, and at the same time realize the bio-based property, replace the traditional petroleum-based resin, and meet the environmental protection trend. Precise matching of 2,5-furandicarboxylic acid with isophthalic acid and adipic acid makes the carboxyl acid value stable at 35-45mgKOH / g, the softening point reaches 70-90℃, the glass transition temperature reaches 40-50℃, and the viscosity (200℃) is 900-1500mPa.s, achieving the balance between resin reaction activity and storage stability, reducing the difficulty of resin melting and improving the flowability of material processing, so that the finally prepared resin can be cured at a low temperature of 100-120℃, while ensuring the salt spray resistance and impact resistance of the coating.

[0027] 2. In the traditional resin synthesis process, one-time feeding and constant temperature reaction are often used. In the present application, alcohol materials are first added, then acid materials are added after melting, and the local reaction imbalance is avoided by staged feeding. At the same time, the reaction process is precisely matched by staged temperature control. The end point of acid value and viscosity is precisely controlled by vacuumizing operation, and the product performance stability is improved.

[0028] 3、The application adopts triglycidyl isocyanurate as a curing agent, which can cross-link with the carboxyl in the resin molecules, so that the powder coating is converted from a liquid state to a solid state to build a coating structure; four butyl ammonium bromide is used as a curing accelerator to reduce the reaction activation energy of triglycidyl isocyanurate in the resin; through the formation of a synergistic system of resin + curing agent + accelerator, the powder coating can be rapidly cured at low temperature, and the thickness of the cured coating is uniform, and the mechanical properties meet the standards.

[0029] 4、Since the powder coating in the application is cured at a lower temperature than the existing powder coating, which is lower than the melting temperature of the plastic device, the powder coating can be applied to the surface of the plastic device, expanding its application scenarios. DETAILED DESCRIPTION

[0030] In order to make the purpose, technical scheme and advantages of the present application clearer, the following further describes the present application with examples. It should be understood that the specific examples described herein are only used to explain the present application, and are not used to limit the present application, that is, the described examples are only a part of the examples of the present application, but not all the examples.

[0031] Therefore, the following detailed description of the provided embodiments of the present application is not intended to limit the scope of the claimed application, but only represents selected embodiments of the present application. Based on the embodiments of the present application, all other embodiments obtained by those skilled in the art without creative labor are within the scope of protection of the present application.

[0032] It should be noted that the relational terms such as "first" and "second" and the like are used only to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply that there is any such actual relationship or order between these entities or operations. Moreover, the terms "comprise", "include" or any other variant thereof are intended to cover non-exclusive inclusion, so that a process, method, article or device including a series of elements includes not only those elements, but also other elements not explicitly listed, or other elements inherent in such a process, method, article or device. Without more limitations, the element defined by the statement "comprising a" does not exclude the presence of additional identical elements in the process, method, article or device including the element.

[0033] The features and properties of the present application are further described in detail below with reference to examples.

[0034] Example 1

[0035] A bio-based low-temperature curing powder coating is made from the following components by weight: bio-based resin 65 parts, trisglycidyl isocyanurate 6 parts, tetrabutylammonium bromide 0.15 parts, air glass microbeads 12 parts, mica 6 parts, ethylene bis-stearamide 0.6 parts, leveling agent 1.3 parts, benzoin 0.5 parts, amide wax 0.45 parts, and pigment 8 parts.

[0036] The bio-based resin comprises the following components by weight: neopentyl glycol 1000 parts, 2,5-furan dicarboxylic acid 1400 parts, trimethylolpropane 16 parts, catalyst (butyl tin oxide) 1 part, isophthalic acid 180 parts, adipic acid 55 parts, antioxidant (β-(3,5-di-tert-butyl-4-hydroxyphenyl) octadecyl propionate) 5 parts, and resin stabilizer (triphenylphosphine) 9 parts.

[0037] The preparation method of the bio-based resin is as follows: (1) neopentyl glycol and trimethylolpropane are added to a reaction kettle with a stirring speed of 30 Hz, heated to melt the materials, then 2,5-furan dicarboxylic acid and catalyst are sequentially added, nitrogen is introduced for protection, and the temperature is continuously raised to 235°C; when the temperature reaches 85°C, 30% of the antioxidant is added, and the reaction is carried out under heat preservation until the acid value is 12 mgKOH / g;

[0038] (2) the material is cooled to 225°C, the stirring is turned off, then isophthalic acid and adipic acid are added, and the stirring speed is set to 70 Hz until the materials are uniformly mixed;

[0039] (3) the material is continuously heated to 235°C, and the reaction is carried out under heat preservation until the acid value of the material reaches 50 mgKOH / g and the viscosity reaches 600 mPa.s;

[0040] (4) 30% of the antioxidant is continuously added, and after stirring and mixing, vacuum is started, and the pressure is raised to above 0.09 MPa within 30 min; the reaction is continuously carried out under vacuum, and the sample is taken every 10 min for detection until the acid value reaches 40 mgKOH / g and the viscosity is 900 mPa.s / 200°C;

[0041] (5) the material is cooled to 210°C, the stirring speed is adjusted to 50 Hz, the remaining 40% of the antioxidant and triphenylphosphine are added, and after the addition is completed, the stirring speed is adjusted to 70 Hz, and the stirring is continued for 40 min to obtain the bio-based resin.

[0042] The preparation method of the bio-based low-temperature curing powder coating comprises the following steps: high-speed mixing, melting, dispersing, extruding, cooling, breaking into flakes, and grinding to a particle size of 35 μm to obtain the bio-based low-temperature curing powder coating.

[0043] Example 2

[0044] A bio-based low-temperature curing powder coating is made from the following components by weight: bio-based resin 75 parts, trisglycidyl isocyanurate 5 parts, tetrabutylammonium bromide 0.05 parts, air glass microbeads 8 parts, mica 4 parts, ethylene bis-stearamide 0.4 parts, leveling agent 0.7 parts, benzoin 0.2 parts, amide wax 0.65 parts and pigment 6 parts.

[0045] The bio-based resin comprises the following components by weight: neopentyl glycol 1200 parts, 2,5-furan dicarboxylic acid 1700 parts, trimethylolpropane 10 parts, catalyst (butyl tin oxide) 1 part, isophthalic acid 220 parts, adipic acid 35 parts, antioxidant (β-(3,5-di-tert-butyl-4-hydroxyphenyl) octadecyl propionate) 9 parts and resin stabilizer (triphenylphosphine) 5 parts.

[0046] The preparation method of the bio-based resin is as follows: (1) neopentyl glycol and trimethylolpropane are added to a reaction kettle with stirring speed of 30 Hz, heated to melt the materials, then 2,5-furan dicarboxylic acid and catalyst are sequentially added, nitrogen is introduced for protection, and the temperature is continuously raised to 245℃, when the temperature reaches 95℃, 30% of the antioxidant is added, and the reaction is carried out under insulation until the acid value is 14 mgKOH / g;

[0047] (2) the material is cooled to 235℃, the stirring is turned off, then isophthalic acid and adipic acid are added, and the stirring speed is set to 70 Hz, and stirring is carried out until the materials are uniformly mixed;

[0048] (3) the material is continuously heated to 245℃, and the reaction is carried out under insulation until the acid value of the material reaches 55 mgKOH / g, and the viscosity reaches 1000 mPa.s;

[0049] (4) 30% of the antioxidant is continuously added, after stirring and mixing, vacuum is started, and the pressure is raised to above 0.09 Mpa within 30 min, and the reaction is continuously carried out under vacuum, and the sample is taken every 10-15 min for detection until the acid value reaches 45 mgKOH / g and the viscosity is 1200 mPa.s / 200℃;

[0050] (5) the material is cooled to 220℃, the stirring speed is adjusted to 50 Hz, the remaining 40% of the antioxidant and triphenylphosphine are added, after the addition is completed, the stirring speed is adjusted to 70 Hz, and the stirring is continued for 40 min to obtain the bio-based resin.

[0051] The preparation method of the bio-based low-temperature curing powder coating comprises the following steps: all raw materials are mixed at high speed, melted and dispersed, extruded, cooled, broken into flakes, and ground to a particle size of 25 μm to obtain the bio-based low-temperature curing powder coating.

[0052] Example 3

[0053] A bio-based low-temperature curing powder coating made from the following components by weight: bio-based resin 68 parts, trisglycidyl isocyanurate 5.5 parts, tetrabutylammonium bromide 0.1 part, air glass microbeads 11 parts, mica 5 parts, ethylene bis-stearamide 0.4 part, leveling agent 1.3 part, benzoin 0.3 part, amide wax 0.6 part and pigment 7.8 parts.

[0054] The bio-based resin comprises the following components by weight: neopentyl glycol 1000 parts, 2,5-furan dicarboxylic acid 1600 parts, trimethylolpropane 14 parts, catalyst (butyl tin oxide) 2 parts, isophthalic acid 190 parts, adipic acid 40 parts, antioxidant (β-(3,5-di-tert-butyl-4-hydroxyphenyl) octadecyl propionate) 6 parts and resin stabilizer (triphenylphosphine) 8 parts.

[0055] The preparation method of the bio-based resin is as follows: (1) neopentyl glycol and trimethylolpropane are added to a reaction kettle with stirring speed of 30 Hz, heated to melt the materials, then 2,5-furan dicarboxylic acid and catalyst are sequentially added, nitrogen is introduced for protection, and the temperature is continuously raised to 240℃, when the temperature reaches 95℃, 30% antioxidant is added, and the reaction is carried out under insulation until the acid value is 14 mgKOH / g;

[0056] (2) The material is cooled to 225℃, the stirring is turned off, then isophthalic acid and adipic acid are added, and the stirring speed is set to 70 Hz, and stirring is carried out until the materials are uniformly mixed;

[0057] (3) The material is continuously heated to 245℃, and the reaction is carried out under insulation until the acid value of the material reaches 50 mgKOH / g and the viscosity reaches 600 mPa.s;

[0058] (4) Continue to add 30% antioxidant, mix evenly after stirring, then start vacuum pumping, pump to above 0.09 Mpa within 30 min, continue to react under vacuum, take sample every 15 min for detection, until the acid value reaches 42 mgKOH / g and the viscosity is 1000 mPa.s / 200℃;

[0059] (5) The material is cooled to 210℃, the stirring speed is adjusted to 50 Hz, the remaining 40% antioxidant and triphenylphosphine are added, the stirring speed is adjusted to 70 Hz after the addition is completed, and the stirring is continued for 40 min to obtain the bio-based resin.

[0060] The preparation method of the above-mentioned bio-based low-temperature curing powder coating comprises the following steps: high-speed mixing, melt dispersion extrusion of all raw materials, crushing into flakes after cooling, and grinding to a particle size of 35 μm to obtain the bio-based low-temperature curing powder coating.

[0061] Example 4

[0062] A bio-based low-temperature curing powder coating is made from the following components by weight: bio-based resin 70 parts, trisglycidyl isocyanurate 5.3 parts, tetrabutylammonium bromide 0.1 part, air glass microbeads 10 parts, mica 5 parts, ethylene bis-stearamide 0.5 part, leveling agent 1 part, benzoin 0.3 part, amide wax 0.5 part, and pigment 7.3 parts.

[0063] The bio-based resin comprises the following components by weight: neopentyl glycol 1135 parts, 2,5-furan dicarboxylic acid 1680 parts, trimethylolpropane 13 parts, catalyst (butyl tin oxide) 2.3 parts, isophthalic acid 200 parts, adipic acid 45 parts, antioxidant (β-(3,5-di-tert-butyl-4-hydroxyphenyl) octadecyl propionate) 7 parts, and resin stabilizer (triphenylphosphine) 7 parts.

[0064] The preparation method of the bio-based resin is as follows: (1) neopentyl glycol and trimethylolpropane are added to a reaction kettle with a stirring speed of 30 Hz, heated to melt the materials, then 2,5-furan dicarboxylic acid and catalyst are sequentially added, nitrogen is introduced for protection, and the temperature is continuously raised to 240℃; when the temperature reaches 90℃, 30% of the antioxidant is added, and the reaction is carried out under heat preservation until the acid value is 13 mgKOH / g;

[0065] (2) the material is cooled to 230℃, the stirring is turned off, then isophthalic acid and adipic acid are added, and the stirring speed is set to 70 Hz until the materials are uniformly mixed;

[0066] (3) the material is continuously heated to 239℃, and the reaction is carried out under heat preservation until the acid value of the material reaches 53 mgKOH / g and the viscosity reaches 800 mPa.s;

[0067] (4) 30% of the antioxidant is continuously added, after stirring and mixing, vacuum is started, and the pressure is raised to above 0.09 Mpa within 30 min; the reaction is continuously carried out under vacuum, and the sample is taken every 12 min for detection until the acid value reaches 43 mgKOH / g and the viscosity is 1100 mPa.s / 200℃;

[0068] (5) the material is cooled to 215℃, the stirring speed is adjusted to 50 Hz, the remaining 40% of the antioxidant and triphenylphosphine are added, after the addition is completed, the stirring speed is adjusted to 70 Hz, and the stirring is continued for 40 min to obtain the bio-based resin.

[0069] The preparation method of the bio-based low-temperature curing powder coating comprises the following steps: high-speed mixing, melting, dispersing, extruding, cooling, breaking into flakes, and grinding to a particle size of 30 μm.

[0070] Test Example

[0071] I. The acid value of the bio-based resin prepared in Example 4 was tested by using standard GB / T6743-2008, and the viscosity of the bio-based resin was tested by using GB / T9751.1-2008 (mpa.s / 200℃).

[0072] The results show that the acid value of the bio-based resin in Example 4 is controlled at 35-45 mgKOH / g, the softening point is controlled at 70-90℃ (the softening point of the general unsaturated polyester on the market is 95-120℃), the glass transition temperature is controlled at 40-50℃ (the glass transition temperature of the general unsaturated polyester on the market is above 55℃), and the viscosity is controlled at (200℃) 900-1500 mPa.s (the viscosity of the general unsaturated polyester on the market is above 3500 mPa.s at 200℃); the softening point, glass transition temperature and viscosity of the bio-based resin in the application are all lower than those of the unsaturated resin on the market; it can be known that the powder coating in the application has a lower curing temperature and can expand the application range.

[0073] II. Taking the material in Example 4 as an example, the material was coated on the surface of a device by electrostatic spraying, and then cured at 100℃ for 40min, at 110℃ for 40min, and at 120℃ for 25min, respectively, to prepare a sample plate with a coating thickness of 60μm.

[0074] Then, 50kg.cm impact tests (GB / T 1732-1993) and neutral salt spray tests (GB / T1771-2024) were performed on the three sample plates, respectively.

[0075] The impact test results show that the coating surfaces of the three sample plates are all free of any visible damage, cracking, coating peeling, substrate exposure and other problems, and all pass the test.

[0076] The neutral salt spray test results show that the coatings of the three sample plates can all maintain a qualified state for more than 500h in the neutral salt spray test environment, and have high salt spray resistance.

Claims

1. A bio-based low-temperature curing powder coating, characterized in that, It comprises the following components in parts by weight: 65-75 parts of bio-based resin, 5-6 parts of triglycidyl isocyanurate, 0.05-0.15 parts of tetrabutylammonium bromide, 8-12 parts of air glass microspheres, 4-6 parts of mica, 0.4-0.6 parts of ethylene bis-stearamide, 0.7-1.3 parts of leveling agent, 0.2-0.5 parts of benzoin, 0.3-0.7 parts of amide wax, and 6-8 parts of pigment; The bio-based resin is made from the following components in parts by weight: 1000-1200 parts neopentyl glycol, 1400-1700 parts 2,5-furandicarboxylic acid, 10-16 parts trimethylolpropane, 1-3.5 parts catalyst, 180-220 parts isophthalic acid, 35-55 parts adipic acid, 5-9 parts antioxidant, and 5-9 parts resin stabilizer; The catalyst is butyltin oxide; the antioxidant is β-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate octadecyl alcohol ester; and the resin stabilizer is triphenylphosphine. The bio-based resin is prepared using the following method: (1) Add neopentyl glycol and trimethylolpropane to a reactor with a stirring speed of 30 Hz, heat until the material melts, then add 2,5-furandicarboxylic acid and catalyst in sequence, purge with nitrogen for protection, and continue to heat to 235-245℃. When the temperature reaches 85-95℃, add 30% antioxidant and keep the reaction at the temperature until the acid value is 12-14 mgKOH / g. (2) Cool the material to 225-235℃, turn off the stirring, then add isophthalic acid and adipic acid, set the stirring speed to 70Hz, and stir until well mixed; (3) Continue to heat the material to 235-245℃ and keep it at that temperature until the acid value of the material reaches 50-55mgKOH / g and the viscosity reaches 600-1000mPa.s; (4) Continue to add 30% antioxidant, stir and mix well, then start vacuuming. Within 30 minutes, the vacuum should reach above 0.09 MPa. Continue the reaction under vacuum, and take samples every 10-15 minutes until the acid value reaches 40-45 mg KOH / g and the viscosity reaches 900-1200 mPa.s / 200℃. (5) Cool the material to 210-220℃, adjust the stirring speed to 50Hz, add the remaining 40% antioxidant and triphenylphosphine, adjust the stirring speed to 70Hz after the feeding is completed, and continue stirring for 40 minutes to obtain bio-based resin.

2. The bio-based low-temperature curing powder coating as described in claim 1, characterized in that, The product comprises the following components in parts by weight: 70 parts of bio-based resin, 5.3 parts of triglycidyl isocyanurate, 0.1 parts of tetrabutylammonium bromide, 10 parts of air glass microspheres, 5 parts of mica, 0.5 parts of ethylene bis-stearamide, 1 part of leveling agent, 0.3 parts of benzoin, 0.5 parts of amide wax, and 7.3 parts of pigment.

3. The bio-based low-temperature curing powder coating as described in claim 1, characterized in that, In step (1), the antioxidant is added when the heating temperature is 240℃ and the cauldron temperature is 90℃.

4. The bio-based low-temperature curing powder coating as described in claim 1, characterized in that, In step (2), the material is cooled to 230°C.

5. The bio-based low-temperature curing powder coating as described in claim 1, characterized in that, In step (3), the temperature is raised to 240°C.

6. The bio-based low-temperature curing powder coating as described in claim 1, characterized in that, In step (5), the temperature is raised to 215°C.

7. The method for preparing the bio-based low-temperature curing powder coating according to any one of claims 1-6, characterized in that, All raw materials are mixed at high speed, melted, dispersed, and extruded. After cooling, they are crushed into flakes and ground to a particle size of 25-35μm to obtain the final product.