High-acid-value polyester resin for TGIC (triglycidyl isocyanurate) dry-mixed extinction type powder coating and preparation method of high-acid-value polyester resin

Abstract

The invention relates to a high-acid-value polyester resin for a TGIC (triglycidyl isocyanurate) dry-mixed extinction type powder coating, which is obtained by copolymerizing 2-methyl-2, 4-pentanediol, pinacol, octadecanedioic acid, 3, 3-dimethyl glutaric acid, 2, 4-dimethylaniline-6-sulfonic acid, isophthalic acid, ethyl malonic acid and the like. Finally, when the high-acid-value polyester resin product provided by the invention is matched with a commercially available low-acid-value polyester resin product to prepare a TGIC (triglycidyl isocyanurate) dry-mixed extinction powder coating, not only can a lower gloss range be realized, but also better leveling level and surface fineness can be obtained, and the defects of the existing high-acid-value polyester resin can be better overcome.

Description

Technical Field

[0001] The invention relates to the technical field of polyester resins, and in particular to a high-acid-value polyester resin for TGIC dry-mixed matte powder coatings, a preparation method thereof, and related applications. Background Art

[0002] At present, as VOC emission standards become increasingly stringent, solvent-based coatings such as paints are gradually facing elimination and transformation. Environmentally friendly, VOC-free coatings are the current and future development direction. Powder coatings are mainly composed of polymer resins, curing agents, additives and fillers. They have the advantages of 100% film formation, no VOC emissions, recyclable coatings, and high cost performance. In recent years, they have developed rapidly in various indoor and outdoor coating fields. In the field of outdoor weather-resistant coatings, TGIC-curing system coatings are used in the largest amount. TGIC-cured coatings are widely used in the decoration field because they have almost no pinholes when thickly coated and have a good surface. With the need for decorative beauty, the application of low-gloss powder coatings has gradually increased. The most commonly used and low-cost matting method in the industry is dry-mixing matting, that is, TGIC powder coatings prepared with high-acid polyester resins (acid values ​​are generally 50-55 mgKOH / g) are mixed with powder coatings prepared with low-acid polyester resins (acid values ​​are generally 17-22 mgKOH / g) in a 1:1 dry method and then cured at high temperature. The difference in curing speed caused by the acid value is used to achieve matting, and finally a dry-mixed matting powder coating is obtained. However, this method currently has the following shortcomings: (1) The glossiness of matting is limited. The matting limit of dry-mixed matting of TGIC system powder coatings can only be about 20% at present. The difference in curing activity caused by the high and low acid values ​​of polyester resins is limited, and it is impossible to achieve a matting effect with a gloss lower than 15%; (2) The surface of the coating film is more likely to have defects of poor fineness, because the acid value of high-acid polyester resins is about 55 mgKOH / g, and the lowest acid value of low-acid polyester resins is about 17 mgKOH / g, with a difference of 38 mgKOH / g. Since both are carboxyl groups, It can only start to solidify when it reaches the same temperature point, such as 200°C. It is difficult to solidify effectively below 200°C, which leads to a rapid difference in the curing speed when it reaches the curing temperature, resulting in an uneven surface. In particular, the molecular structure and activity of high-acid polyester resins have a great influence on the surface fineness of the coating. At present, the surface fineness is still difficult to be satisfactory. The more ideal way is to cure in a step-by-step and gradual manner. This can avoid the problem of poor fineness caused by rapid curing and molding at the same temperature and time period, and can better solve the problem of surface fineness. Summary of the invention

[0003] In view of the above problems, the present invention provides a high acid polyester resin for TGIC dry-mixed matte powder coating, which is mainly obtained by copolymerization of 2-methyl-2,4-pentanediol, pinacol, octadecane dioic acid, 3,3-dimethylglutaric acid, 2,4-dimethylaniline-6-sulfonic acid, isophthalic acid, ethyl malonic acid, etc. When the high acid polyester resin product of the present invention is finally used in combination with a commercially available low acid polyester resin product to prepare TGIC dry-mixed matte powder coating, not only a lower gloss range (8-15%) can be achieved, but also a better leveling grade and surface fineness can be obtained, which better overcomes the defects of the existing high acid polyester resin.

[0004] A high acid value polyester resin for TGIC dry-mixed matte powder coating, comprising the following raw materials in molar parts:

[0005]

[0006] The raw materials also include catalysts and antioxidants.

[0007] Preferably, the catalyst is monobutyltin oxide, and the amount used is 0.08-0.1% of the total mass of the raw materials; the antioxidant is antioxidant 1076, and the amount used is 0.3-0.5% of the total mass of the raw materials.

[0008] The method for preparing a high acid value polyester resin for TGIC dry-mixed matte powder coating as described above comprises the following steps:

[0009] A. Add the formulated amount of 2-methyl-2,4-pentanediol, pinacol and catalyst into the reaction kettle, start stirring, and then heat up to 120-130°C. After the materials become a uniform phase, add the formulated amount of octadecane dioic acid and 3,3-dimethylglutaric acid. After stirring evenly, start heating, gradually heat up to 200-205°C, and continue to heat and polymerize;

[0010] B. Take samples to test the acid value of the polymer. When the acid value of the polymer reaches 70-82 mgKOH / g, add part of the formula amount of isophthalic acid and heat to 220-225°C for chain extension polymerization to adjust the rigidity and water resistance of the polyester chain segment;

[0011] C. Take samples for testing. When the acid value of the polymer reaches 32-38 mgKOH / g, add the formulated amount of antioxidant, stir evenly, start the vacuum system, and continue the vacuum polymerization reaction at 220-225°C.

[0012] D. Take samples to detect the acid value of the polymer in the reactor. When the acid value of the polymer reaches 10-15 mgKOH / g, release the vacuum system, add the formulated amount of 2,4-dimethylaniline-6-sulfonic acid, and heat to 225-230°C for end-capping reaction;

[0013] E. When the acid value of the polymer reaches 2-6 mgKOH / g, it means that 2,4-dimethylaniline-6-sulfonic acid has been grafted to the end group of the polymer and active amino groups have been introduced. At this time, add the formulated amount of mixed acid, specifically ethylmalonic acid and the remaining formulated amount of isophthalic acid, continue to keep warm at 225-230°C for secondary end-capping reaction, and when the acid value of the polymer reaches 39-45 mgKOH / g, stop the reaction, discharge the material while hot, cool the polymer, and then crush and granulate it to obtain polyester resin.

[0014] Preferably, in step A, the temperature is gradually increased to 200-205°C at a heating rate of 16-18°C / h; in step B, two-thirds of the formula amount of isophthalic acid is added, and in step E, one-third of the remaining formula amount of isophthalic acid is added; in step C, the vacuum degree of the vacuum system is controlled between -0.097Mpa and -0.099Mpa; in step E, the polymer is cooled with a steel belt with condensed water.

[0015] The obtained product has the appearance of light yellow transparent resin particles, an acid value of 39-45 mgKOH / g, and a softening point of 103-111°C.

[0016] For example, a method for preparing a high acid value polyester resin for TGIC dry-mixed matte powder coating comprises the following steps:

[0017] A. Add the formulated amount of 2-methyl-2,4-pentanediol, pinacol and catalyst into the reaction kettle, start stirring, and then heat up to 120-130°C. After the materials become a uniform phase, add the formulated amount of octadecane dioic acid and 3,3-dimethylglutaric acid. After stirring evenly, start heating, maintain the heating rate of 16-18°C / h and gradually heat up to 200-205°C, and continue to carry out heat preservation polymerization reaction;

[0018] B. Take samples to test the acid value of the polymer. When the acid value of the polymer reaches 70-82 mgKOH / g, add two-thirds of the formula amount of isophthalic acid and raise the temperature to 220-225°C for chain extension polymerization to adjust the rigidity and water resistance of the polyester chain segment;

[0019] C. Take samples for testing. When the acid value of the polymer reaches 32-38 mgKOH / g, add the formulated amount of antioxidant, stir evenly, start the vacuum system, and continue the vacuum polymerization reaction at 220-225°C. The vacuum degree is controlled between -0.097Mpa and -0.099Mpa.

[0020] D. Take samples to detect the acid value of the polymer in the reactor. When the acid value of the polymer reaches 10-15 mgKOH / g, release the vacuum system, add the formulated amount of 2,4-dimethylaniline-6-sulfonic acid, and heat to 225-230°C for end-capping reaction;

[0021] E. When the acid value of the polymer reaches 2-6 mgKOH / g, it means that 2,4-dimethylaniline-6-sulfonic acid has been grafted to the end group of the polymer and active amino groups have been introduced. At this time, add the mixed acid (ethylmalonic acid and one-third of the remaining isophthalic acid) in the formula amount, continue to keep warm at 225-230 ° C for secondary end-capping reaction, and when the acid value of the polymer reaches 39-45 mgKOH / g, stop the reaction, discharge the material while hot, and cool the polymer with a steel belt with condensed water, and then crush and granulate it to obtain polyester resin.

[0022] The use of the high acid value polyester resin for TGIC dry-mixed matte powder coating as described above or the high acid value polyester resin for TGIC dry-mixed matte powder coating obtained by the method in TGIC dry-mixed matte powder coating.

[0023] The application as described above comprises using the prepared high acid value polyester resin and low acid value polyester resin to prepare corresponding high acid value polyester resin TGIC curing type powder coating and low acid value polyester resin TGIC curing type powder coating respectively, and then dry mixing the corresponding high acid value polyester resin TGIC powder coating and low acid value polyester resin TGIC powder coating respectively in a mass ratio of 1:1, and fully crushing and mixing in a high-speed pulverizer to obtain TGIC dry mixed matte powder coating. Then, the TGIC dry mixed matte powder coating is sprayed on the tinplate substrate after surface treatment by an electrostatic spray gun, and cured to obtain a coating.

[0024] As described above, the preparation method of high acid value polyester resin TGIC curing type powder coating or low acid value polyester resin TGIC curing type powder coating comprises mixing the prepared high acid value polyester resin or low acid value polyester resin with raw materials including TGIC, titanium dioxide, barium sulfate, leveling agent, brightener, and benzoin, extruding, tableting, and crushing with a twin-screw extruder, and then crushing and sieving the flakes to obtain high acid value polyester resin TGIC curing type powder coating or low acid value polyester resin TGIC curing type powder coating.

[0025] Beneficial effects:

[0026] The high acid value polyester resin for TGIC dry-mixed matte powder coating of the present invention is mainly obtained by copolymerizing 2-methyl-2,4-pentanediol, pinacol, octadecane dioic acid, 3,3-dimethylglutaric acid, 2,4-dimethylaniline-6-sulfonic acid, isophthalic acid, ethyl malonic acid and the like.

[0027] Among them, the special flexible raw materials such as 2-methyl-2,4-pentanediol, pinacol, octadecane dioic acid, 3,3-dimethylglutaric acid, and ethylmalonic acid introduced into the segment structure will significantly reduce the softening point of the polyester resin, increase its flowability to achieve better flow effect during curing and achieve the purpose of improving fineness; at the same time, 2-methyl-2,4-pentanediol, pinacol, 3,3-dimethylglutaric acid ethylmalonic acid will reduce its softening point while the branched alkyl will enhance the hydrophobicity of the polyester resin, thereby enhancing its resistance to water boiling and neutral salt spray; and the introduction of the specific amino-terminated raw material 2,4-dimethylaniline-6-sulfonic acid introduces a certain amount of active amino groups into the polyester resin. The low-temperature curing activity of the amino group is higher than that of the carboxyl group, so that it can be gradually cured after the sample is heated to 150°C, which reduces the The problem of rapid curing affecting the surface fineness occurs at the same temperature and time period. On the other hand, due to the difference in curing activity and functional groups between amino and carboxyl groups, the gloss of the coating can be further reduced. Moreover, in order to further increase the difference in carboxyl groups, the final polyester resin is carboxyl-terminated with a mixed acid (isophthalic acid and ethylmalonic acid), and the carboxyl activity of the polyester end-capping also shows obvious differences. When the final polyester resin is cured with TGIC, the difference in its active end groups (carboxyl groups and amino groups with different activities) and the curing sequence can be more effectively enhanced. Due to the participation of the terminal amino group, the acid value of the high acid value polyester resin of the present invention can be reduced from 55 mgKOH / g of an ordinary high acid value to 39-45 mgKOH / g, reducing the acid value difference of 17 mgKOH / g with the low acid value polyester resin, which is of great help in improving the surface fineness.

[0028] Finally, when the high acid value polyester resin product of the present invention is used in combination with a commercially available low acid value polyester resin product to prepare a TGIC dry mixed matte powder coating, not only a lower gloss range (8-15%) can be achieved, but also a better leveling grade and surface fineness can be obtained, thereby better overcoming the defects of the existing high acid value polyester resin. DETAILED DESCRIPTION

[0029] The present invention is further described below in conjunction with embodiments. It should be noted that, in the absence of conflict, the embodiments in this application and the technical features in the embodiments can be combined with each other. It should be noted that, unless otherwise specified, all technical and scientific terms used in this application have the same meanings as those generally understood by those of ordinary skill in the art to which this application belongs. The words "including" or "comprising" and the like used in the disclosure of the present invention mean that the elements or objects appearing before the word cover the elements or objects listed after the word and their equivalents, without excluding other elements or objects.

[0030] The raw materials described in the present invention are all commercially available.

[0031] Preparation Example 1

[0032] A high acid value polyester resin for TGIC dry-mixed matte powder coating, comprising the following raw materials in molar parts:

[0033]

[0034] The catalyst is monobutyltin oxide, and the amount used is 0.1% of the total mass of the raw materials;

[0035] The antioxidant is antioxidant 1076, and the dosage is 0.3% of the total weight of the raw materials.

[0036] The preparation method of a high acid value polyester resin for TGIC dry-mixed matte powder coating comprises the following steps:

[0037] A. Add the formulated amount of 2-methyl-2,4-pentanediol, pinacol and catalyst into the reaction kettle, start stirring, and then heat up to 120°C. After the materials become a uniform phase, add the formulated amount of octadecane dioic acid and 3,3-dimethylglutaric acid. After stirring evenly, start heating, maintain the heating rate of 16°C / h and gradually heat up to 200°C, and continue to carry out heat preservation polymerization reaction;

[0038] B. Take samples to test the acid value of the polymer. When the acid value of the polymer reaches 70-82 mgKOH / g, add two-thirds of the formula amount of isophthalic acid and heat to 220°C for chain extension polymerization to adjust the rigidity and water resistance of the polyester chain segment;

[0039] C. Take samples for testing. When the acid value of the polymer reaches 32-38 mgKOH / g, add the formulated amount of antioxidant, stir evenly, start the vacuum system, and continue the vacuum polymerization reaction at 220°C. The vacuum degree is controlled at -0.099Mpa.

[0040] D. Take samples to detect the acid value of the polymer in the reactor. When the acid value of the polymer reaches 10-15 mgKOH / g, release the vacuum system, add the formulated amount of 2,4-dimethylaniline-6-sulfonic acid, and heat to 225°C for end-capping reaction;

[0041] E. When the acid value of the polymer reaches 2-6 mgKOH / g, it means that 2,4-dimethylaniline-6-sulfonic acid has been grafted to the end group of the polymer and active amino groups have been introduced. At this time, add the mixed acid (ethylmalonic acid and one-third of the remaining isophthalic acid) in the formula amount, continue to keep warm at 225°C for secondary end-capping reaction, and when the acid value of the polymer reaches the expected value, stop the reaction, discharge the material while hot, and cool the polymer with a steel belt with condensed water, then crush and granulate it to obtain polyester resin.

[0042] The obtained product has the appearance of light yellow transparent resin particles, an acid value of 40 mgKOH / g, and a softening point of 107°C.

[0043] Preparation Example 2

[0044] A high acid value polyester resin for TGIC dry-mixed matte powder coating, comprising the following raw materials in molar parts:

[0045]

[0046] The catalyst is monobutyltin oxide, and the amount used is 0.1% of the total mass of the raw materials;

[0047] The antioxidant is antioxidant 1076, and the dosage is 0.5% of the total weight of the raw materials.

[0048] The preparation method is the same as that of Preparation Example 1.

[0049] The obtained product has the appearance of light yellow transparent resin particles, an acid value of 45 mgKOH / g, and a softening point of 104°C.

[0050] Preparation Example 3

[0051] A high acid value polyester resin for TGIC dry-mixed matte powder coating, comprising the following raw materials in molar parts:

[0052]

[0053] The catalyst is monobutyltin oxide, and the amount used is 0.1% of the total mass of the raw materials;

[0054] The antioxidant is antioxidant 1076, and the dosage is 0.5% of the total weight of the raw materials.

[0055] The preparation method is the same as that of Preparation Example 1.

[0056] The obtained product has the appearance of light yellow transparent resin particles, an acid value of 43 mgKOH / g, and a softening point of 108°C.

[0057] Preparation Example 4

[0058] A high acid value polyester resin for TGIC dry-mixed matte powder coating, comprising the following raw materials in molar parts:

[0059]

[0060] The catalyst is monobutyltin oxide, and the amount used is 0.1% of the total mass of the raw materials;

[0061] The antioxidant is antioxidant 1076, and the dosage is 0.5% of the total weight of the raw materials.

[0062] The preparation method is the same as that of Preparation Example 1.

[0063] The obtained product has the appearance of light yellow transparent resin particles, an acid value of 42 mgKOH / g, and a softening point of 110°C.

[0064] Comparative Preparation Example 1: Using a commercially available general-purpose TGIC dry-mixed matting polyester resin with a high acid value, an acid value of 54 mgKOH / g, a softening point of 118°C, model SJ4H, Anhui Shenjian New Materials Co., Ltd.;

[0065] Examples 1-4 and Comparative Example 1 (using the high acid value polyester resins obtained in Preparation Examples 1-4 and Comparative Preparation Example 1, respectively)

[0066] The formula of high acid value polyester resin TGIC curing powder coating is as follows in parts by weight:

[0067]

[0068] The formula of low acid value polyester resin TGIC curing powder coating is as follows in parts by weight:

[0069]

[0070] The low acid value polyester resin is a common commercial product with an acid value of 17 mgKOH / g, model SJ4G, Anhui Shenjian New Materials Co., Ltd., and other raw materials are all common commercial products.

[0071] Preparation of coating: Prepare Examples 1-4 and Comparative Preparation Example 1 according to the above-mentioned high acid value polyester resin TGIC powder coating formula, mix the materials, extrude, tablet, and crush with a twin-screw extruder, and then crush the flakes to make a high acid value polyester resin TGIC curing type powder coating for standby use. Then, according to the above-mentioned low acid value polyester resin TGIC powder coating formula, mix the materials, extrude, tablet, and crush with a twin-screw extruder, and then crush the flakes to make a low acid value polyester resin TGIC curing type powder coating.

[0072] Then, the corresponding high acid value polyester resin TGIC powder coating and low acid value polyester resin TGIC powder coating are dry mixed according to a mass ratio of 1:1, and fully crushed and mixed in a high-speed grinder for 2-3 minutes. Then, the TGIC cured dry mixed matte finished powder coating is obtained, and it is sprayed on the surface treated tinplate substrate with an electrostatic spray gun, with a film thickness of about 80μm, and cured at 200℃ / 15min to obtain the coating.

[0073] Performance comparison

[0074] Coating index testing is based on: GB / T 21776-2008 "Guide to Testing Standards for Powder Coatings and Their Coatings". The leveling grade is carried out using the PCI grading method, 0-10 grades, the larger the number, the better the leveling. The neutral salt spray resistance test is based on GB / 1771-2007 "Determination of Neutral Salt Spray Resistance of Paints and Varnishes". The test panel is placed in a salt spray chamber at an angle of 15-25°, sprayed at a spray volume of 3%, and the results are observed after 168 hours.

[0075] The polyester resins prepared in the above examples and comparative examples were used to prepare coatings according to the coating formulations provided by the present invention, and the coating properties were tested as shown in Table 1 below.

[0076] Table 1 Properties of powder coating films

[0077]

[0078]

[0079] As can be seen from Table 1, the high acid value polyester resin product prepared by the present invention adopts a specific formula and process, introduces a special flexible hydrophobic branched monomer and an active amino group, and realizes the improvement of its matting ability and resistance to water boiling and neutral salt spray, and the function of better surface fineness. Finally, the high acid value polyester powder coating prepared by high acid value polyester resin and TGIC and the powder coating prepared by ordinary commercially available low acid value polyester resin products are dry mixed and matted in a mass ratio of 1:1 to prepare a finished dry mixed matting powder coating. The coating film is cured at 200℃ / 15min, and the coating film has a smooth and smooth appearance, and the surface fineness is better, the gloss is basically between 8-14%, the leveling grade is basically 6 and above, the surface does not change after boiling in boiling water for 2h, and the coating film surface has no obvious change after 168h of neutral salt spray resistance.

[0080] Comparative Example 1 uses a common commercially available high-acid polyester resin product. The powder coating prepared from it and the low-acid polyester resin has a slightly poor surface fineness and a gloss of 22.3%, which is higher than the gloss range of the product of the present invention. In addition, the leveling grade can only reach level 5, and the boiling water resistance and neutral salt spray resistance are also slightly worse than the product of the present invention.

[0081] The above description is only by way of illustration of certain exemplary embodiments of the present invention. It is undoubted that, for those skilled in the art, the described embodiments can be modified in various ways without departing from the spirit and scope of the present invention. Therefore, the above description is illustrative in nature and should not be construed as limiting the scope of protection of the claims of the present invention.

Claims

1. A high acid value polyester resin for TGIC dry-mixed matte powder coating, characterized in that: The raw materials comprising the following molar compositions: The raw materials also include catalysts and antioxidants.

2. A TGIC dry-blended high acid value polyester resin for matte powder coating according to claim 1, characterized in that: The catalyst is monobutyltin oxide, and the amount used is 0.08-0.1% of the total mass of the raw materials.

3. A TGIC dry-blended high acid polyester resin for matte powder coating according to claim 1, characterized in that: The antioxidant is antioxidant 1076, and the dosage is 0.3-0.5% of the total weight of the raw materials.

4. The method for preparing a high acid value polyester resin for TGIC dry-mixed matte powder coating according to any one of claims 1 to 3, characterized in that: The following steps are involved: A. Add the formulated amount of 2-methyl-2,4-pentanediol, pinacol and catalyst into the reaction kettle, start stirring, and then heat up to 120-130°C. After the materials become a uniform phase, add the formulated amount of octadecane dioic acid and 3,3-dimethylglutaric acid. After stirring evenly, start heating, gradually heat up to 200-205°C, and continue to heat and polymerize; B. Take samples to test the acid value of the polymer. When the acid value of the polymer reaches 70-82 mgKOH / g, add part of the formula amount of isophthalic acid and heat to 220-225°C for chain extension polymerization to adjust the rigidity and water resistance of the polyester chain segment; C. Take samples for testing. When the acid value of the polymer reaches 32-38 mgKOH / g, add the formulated amount of antioxidant, stir evenly, start the vacuum system, and continue the vacuum polymerization reaction at 220-225°C. D. Take samples to detect the acid value of the polymer in the reactor. When the acid value of the polymer reaches 10-15 mgKOH / g, release the vacuum system, add the formulated amount of 2,4-dimethylaniline-6-sulfonic acid, and heat to 225-230°C for end-capping reaction; E. When the acid value of the polymer reaches 2-6 mgKOH / g, it means that 2,4-dimethylaniline-6-sulfonic acid has been grafted to the end group of the polymer and active amino groups have been introduced. At this time, add the formulated amount of mixed acid, specifically ethylmalonic acid and the remaining formulated amount of isophthalic acid, continue to keep warm at 225-230°C for secondary end-capping reaction, and when the acid value of the polymer reaches 39-45 mgKOH / g, stop the reaction, discharge the material while hot, cool the polymer, and then crush and granulate it to obtain polyester resin.

5. The method for preparing a TGIC dry-mixed matte powder coating high acid value polyester resin as claimed in claim 4, characterized in that: In step A, the temperature is gradually increased to 200-205° C. at a heating rate of 16-18° C. / h.

6. The method for preparing a TGIC dry-mixed high acid value polyester resin for matte powder coating according to claim 4, characterized in that: In step B, two-thirds of the formula amount of isophthalic acid is added, and in step E, one-third of the remaining formula amount of isophthalic acid is added.

7. The method for preparing a TGIC dry-blended high acid value polyester resin for matte powder coating according to claim 4, characterized in that: In step C, the vacuum degree of the vacuum system is controlled between -0.097 MPa and -0.099 MPa; in step E, the polymer is cooled by a steel belt with condensed water.

8. Use of the high acid value polyester resin for TGIC dry-blended matte powder coating according to claims 1-3 or the high acid value polyester resin for TGIC dry-blended matte powder coating obtained by the method according to claims 4-7 in TGIC dry-blended matte powder coating.

9. The use as claimed in claim 8, comprising using the prepared high acid value polyester resin and low acid value polyester resin to prepare corresponding high acid value polyester resin TGIC curing type powder coating and low acid value polyester resin TGIC curing type powder coating, respectively, and then dry mixing the corresponding high acid value polyester resin TGIC powder coating and low acid value polyester resin TGIC powder coating respectively in a mass ratio of 1:1, and fully pulverizing and mixing them in a high-speed pulverizer to obtain TGIC dry mixed matte powder coating.

10. The use according to claim 9, characterized in that: The preparation method of high acid value polyester resin TGIC curing type powder coating or low acid value polyester resin TGIC curing type powder coating comprises the steps of uniformly mixing the prepared high acid value polyester resin or low acid value polyester resin with raw materials including TGIC, titanium dioxide, barium sulfate, leveling agent, leveling agent, brightener and benzoin, extruding, tabletting and crushing by a twin-screw extruder, and then crushing and sieving the tablets to obtain high acid value polyester resin TGIC curing type powder coating or low acid value polyester resin TGIC curing type powder coating.

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