Black high gloss polyester powder coating and method for preparing the same

Abstract

This invention discloses a black high-gloss polyester powder coating and its preparation method, relating to the field of coating technology. It comprises the following components: polyester resin, curing agent, carbon black, high-gloss additive, filler, antioxidant, and leveling agent; wherein the mass ratio of carbon black to high-gloss additive is 4:1; and wherein the polyester resin used is an unsaturated polyester resin. The polyester powder coating prepared by this invention, after spraying, forms a coating that does not peel off or bubble, and has high gloss. The polyester powder coating prepared by this invention does not contain solvents, thus avoiding the volatilization of organic solvents, making it green and safe. The high-gloss additive formulated in this invention can significantly improve the gloss of the coating and greatly enhance its gloss retention performance. By introducing the high-gloss additive prepared by this invention, it can effectively fill the grooves and pores on the coating surface, thereby significantly improving the density of the coating surface.

Description

Technical Field

[0001] This invention belongs to the field of coating technology, specifically a black high-gloss polyester powder coating and its preparation method. Background Technology

[0002] Powder coating is a green coating that does not require volatile solvents. Because it does not require solvents, powder coating has many advantages such as low pollution, high material utilization, and low energy consumption, and is widely used in many fields.

[0003] Powder coatings are broadly classified into thermoplastic and thermosetting types. Thermoplastic powder coatings have a poorer film appearance (gloss and leveling properties), but their adhesion to the substrate is also relatively weak. Thermosetting powder coatings use thermosetting synthetic resins as film-forming substances. During the drying process, the resin first melts and then is chemically cross-linked and cured into a smooth and hard film.

[0004] Thermosetting powder coatings mainly utilize the cross-linking reaction that occurs when the resin and curing agent are heated to form a hard, non-melting coating. Even at high ambient temperatures, this coating will only decompose and will not soften like thermoplastic resin coatings, thus possessing strong mechanical properties.

[0005] Polyester powder coatings, as an important type of powder coating, have good weather resistance and climate stability, as well as good adhesion and good bonding strength with various substrates. However, due to the inherent properties of polyester, its performance deteriorates after prolonged exposure to ultraviolet light, resulting in a decrease in durability, a significant reduction in gloss, and a decrease in abrasion resistance, which seriously affects its use.

[0006] Based on this, a black high-gloss polyester powder coating and its preparation method are provided to solve the existing technical problems. Summary of the Invention

[0007] The purpose of this invention is to provide a black high-gloss polyester powder coating and its preparation method to overcome the shortcomings of the prior art.

[0008] The technical solution adopted in this invention is as follows:

[0009] A black high-gloss polyester powder coating, comprising the following components by weight: 85-94 parts polyester resin, 6-8 parts curing agent, 2-3.2 parts carbon black, 0.5-0.8 parts high-gloss additive, 23-25 ​​parts filler, 0.8-1.2 parts antioxidant, and 1-2 parts leveling agent;

[0010] The mass ratio of carbon black to high-gloss additive is 4:1.

[0011] The polyester resin used is an unsaturated polyester resin.

[0012] As a further technical solution: the method for preparing the high-gloss additive is as follows:

[0013] (1) Add organic solvent to the reactor, and then add butyl acrylate, methyl methacrylate and graphene to the reactor in sequence. Stir and mix at 550 r / min for 20 min to obtain the base liquid.

[0014] (2) Add the initiator to the organic solvent and stir at 500 r / min to mix evenly to obtain an initiator solution;

[0015] (3) The prepared initiator solution is added dropwise into the reaction vessel, and then the reaction is carried out at 80°C with stirring for 2 hours. First, a portion of the organic solvent is removed by atmospheric distillation, and then the remaining organic solvent is removed by vacuum distillation. Finally, the mixture is crushed and then passed through a 500-mesh sieve to obtain the high-gloss additive.

[0016] As a further technical solution: the graphene undergoes pre-modification treatment:

[0017] Graphene and maleic anhydride were added to a nitric acid solution, the temperature was adjusted to 60°C, and the mixture was stirred for 15 minutes. Then, the temperature was adjusted to 85°C, and the mixture was stirred for another 20 minutes. The mixture was then filtered, washed with water until neutral, and dried to constant weight to obtain preliminary graphene.

[0018] The preliminary graphene and cerium chloride obtained above were mixed evenly at a mass ratio of 1000:1, and then subjected to plasma treatment for 1 hour under a nitrogen atmosphere with a power of 300W. After discharge, the mixture was washed with a 50% ethanol solution, filtered, and dried to constant weight to complete the treatment.

[0019] The mass ratio of graphene, maleic anhydride, and nitric acid solution is 1:3:10.

[0020] The nitric acid solution has a mass fraction of 12%.

[0021] The drying temperature was 60℃ and the drying time was 40 minutes.

[0022] As a further technical solution: the organic solvent is xylene;

[0023] The mass ratio of xylene, butyl acrylate, methyl methacrylate, and graphene is 30:5-8:4-6:0.6-0.8.

[0024] The initiator is benzoyl peroxide;

[0025] The initiator solution has a mass fraction of 5%.

[0026] The mass ratio of the initiator solution to the base solution is 1:5-6.

[0027] As a further technical solution: the curing agent is diaminophenyl sulfone.

[0028] As a further technical solution: the filler is a mixture of titanium dioxide and calcium carbonate;

[0029] The mass ratio of titanium dioxide to calcium carbonate is 1:8.

[0030] As a further technical solution: the antioxidant is antioxidant 1010.

[0031] As a further technical solution: the leveling agent is polyacrylate.

[0032] A method for preparing a black high-gloss polyester powder coating includes the following steps:

[0033] S1. First, add polyester resin, curing agent, carbon black, high-gloss additive, filler, antioxidant, and leveling agent to the mixer and mix for 15 minutes to obtain a mixture;

[0034] The high-speed mixing speed is 800 r / min;

[0035] S2. Then add the mixture obtained above into a dryer for drying;

[0036] The drying temperature is 60℃ and the drying time is 2 hours.

[0037] S3. Add the dried mixture to a twin-screw extruder and melt-extrude it;

[0038] S4. After being melt-extruded by a twin-screw extruder, the material is conveyed to a tablet press for tableting to obtain a sheet. The sheet is then crushed and sieved to obtain the finished black high-gloss polyester powder coating.

[0039] The black high-gloss polyester powder coating has an average particle size of 30μm.

[0040] Beneficial effects:

[0041] The polyester powder coating prepared by this invention forms a coating that does not peel off or bubble after spraying, and has high gloss.

[0042] The polyester powder coating prepared by this invention does not contain solvents and does not produce the phenomenon of organic solvent volatilization, making it green and safe.

[0043] The present invention can significantly improve the gloss of the coating by formulating a high-gloss additive, and also greatly enhance the gloss retention performance of the coating. By introducing the high-gloss additive prepared by the present invention, it can effectively fill the grooves and pores on the coating surface, thereby significantly improving the density of the coating surface. After filling the uneven surface of the coating surface into a smooth and flat surface, it can significantly improve the light reflection effect of the coating surface and improve the gloss performance of the coating.

[0044] This invention introduces a mixture of titanium dioxide and calcium carbonate as fillers into the coating. This not only effectively improves the mechanical properties of the coating but also provides excellent hiding power, allowing the coating to completely cover the substrate surface and resulting in good uniformity. Furthermore, the introduced titanium dioxide further enhances the smoothness of the coating, giving it a better gloss effect. Due to the uniform distribution of titanium dioxide in the coating, its combination with high-gloss additives significantly absorbs ultraviolet rays, thereby greatly improving the coating's aging resistance and gloss retention. Attached Figure Description

[0045] Figure 1 The bar chart shows the gloss retention properties of the examples and comparative examples. Detailed Implementation

[0046] The technical solutions in the embodiments of the present invention will be clearly and completely described below. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0047] Example 1

[0048] A black high-gloss polyester powder coating is made of the following components by weight: 85 parts polyester resin, 6 parts diaminophenyl sulfone, 2 parts carbon black, 0.5 parts high-gloss additive, 23 parts filler, 0.8 parts antioxidant 1010, and 1 part polyacrylate.

[0049] The mass ratio of carbon black to high-gloss additive is 4:1.

[0050] The polyester resin used is di(2-ethylhexyl) phthalate.

[0051] The preparation method of the high-gloss additive is as follows:

[0052] (1) Add xylene to the reactor, and then add butyl acrylate, methyl methacrylate and graphene to the reactor in sequence. Stir and mix at 550 r / min for 20 min to obtain the base liquid.

[0053] (2) Add the initiator to xylene and stir at 500 r / min to mix evenly to obtain an initiator solution;

[0054] (3) The prepared initiator solution is added dropwise into the reaction vessel, and then the reaction is carried out at 80°C with stirring for 2 hours. First, a portion of xylene is removed by atmospheric distillation, and then the remaining xylene is removed by vacuum distillation. Finally, it is pulverized and then passed through a 500-mesh sieve to obtain the high-gloss additive.

[0055] Graphene after pre-modification treatment:

[0056] Graphene and maleic anhydride were added to a nitric acid solution, the temperature was adjusted to 60°C, and the mixture was stirred for 15 minutes. Then, the temperature was adjusted to 85°C, and the mixture was stirred for another 20 minutes. The mixture was then filtered, washed with water until neutral, and dried to constant weight to obtain preliminary graphene.

[0057] The preliminary graphene and cerium chloride obtained above were mixed evenly at a mass ratio of 1000:1, and then subjected to plasma treatment for 1 hour under a nitrogen atmosphere with a power of 300W. After discharge, the mixture was washed with a 50% ethanol solution, filtered, and dried to constant weight to complete the treatment.

[0058] The mass ratio of graphene, maleic anhydride, and nitric acid solution is 1:3:10.

[0059] The nitric acid solution has a mass fraction of 12%.

[0060] The drying temperature was 60℃ and the drying time was 40 minutes.

[0061] The mass ratio of xylene, butyl acrylate, methyl methacrylate, and graphene is 30:5:4:0.6.

[0062] The initiator is benzoyl peroxide;

[0063] The initiator solution has a mass fraction of 5%.

[0064] The initiator solution and base liquid are mixed in a mass ratio of 1:5; the filler is a mixture of titanium dioxide and calcium carbonate.

[0065] The mass ratio of titanium dioxide to calcium carbonate is 1:8.

[0066] A method for preparing a black high-gloss polyester powder coating includes the following steps:

[0067] S1. First, add polyester resin, curing agent, carbon black, high-gloss additive, filler, antioxidant, and leveling agent to the mixer and mix for 15 minutes to obtain a mixture;

[0068] The high-speed mixing speed is 800 r / min;

[0069] S2. Then add the mixture obtained above into a dryer for drying;

[0070] The drying temperature is 60℃ and the drying time is 2 hours.

[0071] S3. Add the dried mixture to a twin-screw extruder and melt-extrude it;

[0072] S4. After being melt-extruded by a twin-screw extruder, the material is conveyed to a tablet press for tableting to obtain a sheet. The sheet is then crushed and sieved to obtain the finished black high-gloss polyester powder coating.

[0073] The black high-gloss polyester powder coating has an average particle size of 30μm.

[0074] Example 2

[0075] A black high-gloss polyester powder coating is made of the following components by weight: 88 parts polyester resin, 6.5 parts diaminophenyl sulfone, 2.4 parts carbon black, 0.6 parts high-gloss additive, 24 parts filler, 0.9 parts antioxidant 1010, and 1.5 parts polyacrylate.

[0076] The mass ratio of carbon black to high-gloss additive is 4:1.

[0077] The polyester resin used is di(2-ethylhexyl) phthalate.

[0078] The preparation method of the high-gloss additive is as follows:

[0079] (1) Add xylene to the reactor, and then add butyl acrylate, methyl methacrylate and graphene to the reactor in sequence. Stir and mix at 550 r / min for 20 min to obtain the base liquid.

[0080] (2) Add the initiator to xylene and stir at 500 r / min to mix evenly to obtain an initiator solution;

[0081] (3) The prepared initiator solution is added dropwise into the reaction vessel, and then the reaction is carried out at 80°C with stirring for 2 hours. First, a portion of xylene is removed by atmospheric distillation, and then the remaining xylene is removed by vacuum distillation. Finally, it is pulverized and then passed through a 500-mesh sieve to obtain the high-gloss additive.

[0082] Graphene after pre-modification treatment:

[0083] Graphene and maleic anhydride were added to a nitric acid solution, the temperature was adjusted to 60°C, and the mixture was stirred for 15 minutes. Then, the temperature was adjusted to 85°C, and the mixture was stirred for another 20 minutes. The mixture was then filtered, washed with water until neutral, and dried to constant weight to obtain preliminary graphene.

[0084] The preliminary graphene and cerium chloride obtained above were mixed evenly at a mass ratio of 1000:1, and then subjected to plasma treatment for 1 hour under a nitrogen atmosphere with a power of 300W. After discharge, the mixture was washed with a 50% ethanol solution, filtered, and dried to constant weight to complete the treatment.

[0085] The mass ratio of graphene, maleic anhydride, and nitric acid solution is 1:3:10.

[0086] The nitric acid solution has a mass fraction of 12%.

[0087] The drying temperature was 60℃ and the drying time was 40 minutes.

[0088] The mass ratio of xylene, butyl acrylate, methyl methacrylate, and graphene is 30:6:5:0.7.

[0089] The initiator is benzoyl peroxide;

[0090] The initiator solution has a mass fraction of 5%.

[0091] The initiator solution and base liquid are mixed in a mass ratio of 1:5.5; the filler is a mixture of titanium dioxide and calcium carbonate.

[0092] The mass ratio of titanium dioxide to calcium carbonate is 1:8.

[0093] A method for preparing a black high-gloss polyester powder coating includes the following steps:

[0094] S1. First, add polyester resin, curing agent, carbon black, high-gloss additive, filler, antioxidant, and leveling agent to the mixer and mix for 15 minutes to obtain a mixture;

[0095] The high-speed mixing speed is 800 r / min;

[0096] S2. Then add the mixture obtained above into a dryer for drying;

[0097] The drying temperature is 60℃ and the drying time is 2 hours.

[0098] S3. Add the dried mixture to a twin-screw extruder and melt-extrude it;

[0099] S4. After being melt-extruded by a twin-screw extruder, the material is conveyed to a tablet press for tableting to obtain a sheet. The sheet is then crushed and sieved to obtain the finished black high-gloss polyester powder coating.

[0100] The black high-gloss polyester powder coating has an average particle size of 30μm.

[0101] Example 3

[0102] A black high-gloss polyester powder coating is made of the following components by weight: 90 parts polyester resin, 7 parts diaminophenyl sulfone, 2.8 parts carbon black, 0.7 parts high-gloss additive, 24 parts filler, 10101 parts antioxidant, and 1.5 parts polyacrylate.

[0103] The mass ratio of carbon black to high-gloss additive is 4:1.

[0104] The polyester resin used is di(2-ethylhexyl) phthalate.

[0105] The preparation method of the high-gloss additive is as follows:

[0106] (1) Add xylene to the reactor, and then add butyl acrylate, methyl methacrylate and graphene to the reactor in sequence. Stir and mix at 550 r / min for 20 min to obtain the base liquid.

[0107] (2) Add the initiator to xylene and stir at 500 r / min to mix evenly to obtain an initiator solution;

[0108] (3) The prepared initiator solution is added dropwise into the reaction vessel, and then the reaction is carried out at 80°C with stirring for 2 hours. First, a portion of xylene is removed by atmospheric distillation, and then the remaining xylene is removed by vacuum distillation. Finally, it is pulverized and then passed through a 500-mesh sieve to obtain the high-gloss additive.

[0109] Graphene after pre-modification treatment:

[0110] Graphene and maleic anhydride were added to a nitric acid solution, the temperature was adjusted to 60°C, and the mixture was stirred for 15 minutes. Then, the temperature was adjusted to 85°C, and the mixture was stirred for another 20 minutes. The mixture was then filtered, washed with water until neutral, and dried to constant weight to obtain preliminary graphene.

[0111] The preliminary graphene and cerium chloride obtained above were mixed evenly at a mass ratio of 1000:1, and then subjected to plasma treatment for 1 hour under a nitrogen atmosphere with a power of 300W. After discharge, the mixture was washed with a 50% ethanol solution, filtered, and dried to constant weight to complete the treatment.

[0112] The mass ratio of graphene, maleic anhydride, and nitric acid solution is 1:3:10.

[0113] The nitric acid solution has a mass fraction of 12%.

[0114] The drying temperature was 60℃ and the drying time was 40 minutes.

[0115] The mass ratio of xylene, butyl acrylate, methyl methacrylate, and graphene is 30:7:5:0.7.

[0116] The initiator is benzoyl peroxide;

[0117] The initiator solution has a mass fraction of 5%.

[0118] The initiator solution and base liquid are mixed in a mass ratio of 1:5.8; the filler is a mixture of titanium dioxide and calcium carbonate.

[0119] The mass ratio of titanium dioxide to calcium carbonate is 1:8.

[0120] A method for preparing a black high-gloss polyester powder coating includes the following steps:

[0121] S1. First, add polyester resin, curing agent, carbon black, high-gloss additive, filler, antioxidant, and leveling agent to the mixer and mix for 15 minutes to obtain a mixture;

[0122] The high-speed mixing speed is 800 r / min;

[0123] S2. Then add the mixture obtained above into a dryer for drying;

[0124] The drying temperature is 60℃ and the drying time is 2 hours.

[0125] S3. Add the dried mixture to a twin-screw extruder and melt-extrude it;

[0126] S4. After being melt-extruded by a twin-screw extruder, the material is conveyed to a tablet press for tableting to obtain a sheet. The sheet is then crushed and sieved to obtain the finished black high-gloss polyester powder coating.

[0127] The black high-gloss polyester powder coating has an average particle size of 30μm.

[0128] Example 4

[0129] A black high-gloss polyester powder coating is made of the following components by weight: 92 parts polyester resin, 7 parts diaminophenyl sulfone, 2.8 parts carbon black, 0.7 parts high-gloss additive, 24 parts filler, 1.2 parts antioxidant 1010, and 2 parts polyacrylate.

[0130] The mass ratio of carbon black to high-gloss additive is 4:1.

[0131] The polyester resin used is di(2-ethylhexyl) phthalate.

[0132] The preparation method of the high-gloss additive is as follows:

[0133] (1) Add xylene to the reactor, and then add butyl acrylate, methyl methacrylate and graphene to the reactor in sequence. Stir and mix at 550 r / min for 20 min to obtain the base liquid.

[0134] (2) Add the initiator to xylene and stir at 500 r / min to mix evenly to obtain an initiator solution;

[0135] (3) The prepared initiator solution is added dropwise into the reaction vessel, and then the reaction is carried out at 80°C with stirring for 2 hours. First, a portion of xylene is removed by atmospheric distillation, and then the remaining xylene is removed by vacuum distillation. Finally, it is pulverized and then passed through a 500-mesh sieve to obtain the high-gloss additive.

[0136] Graphene after pre-modification treatment:

[0137] Graphene and maleic anhydride were added to a nitric acid solution, the temperature was adjusted to 60°C, and the mixture was stirred for 15 minutes. Then, the temperature was adjusted to 85°C, and the mixture was stirred for another 20 minutes. The mixture was then filtered, washed with water until neutral, and dried to constant weight to obtain preliminary graphene.

[0138] The preliminary graphene and cerium chloride obtained above were mixed evenly at a mass ratio of 1000:1, and then subjected to plasma treatment for 1 hour under a nitrogen atmosphere with a power of 300W. After discharge, the mixture was washed with a 50% ethanol solution, filtered, and dried to constant weight to complete the treatment.

[0139] The mass ratio of graphene, maleic anhydride, and nitric acid solution is 1:3:10.

[0140] The nitric acid solution has a mass fraction of 12%.

[0141] The drying temperature was 60℃ and the drying time was 40 minutes.

[0142] The mass ratio of xylene, butyl acrylate, methyl methacrylate, and graphene is 30:6:5:0.6.

[0143] The initiator is benzoyl peroxide;

[0144] The initiator solution has a mass fraction of 5%.

[0145] The initiator solution and base liquid are mixed in a mass ratio of 1:5; the filler is a mixture of titanium dioxide and calcium carbonate.

[0146] The mass ratio of titanium dioxide to calcium carbonate is 1:8.

[0147] A method for preparing a black high-gloss polyester powder coating includes the following steps:

[0148] S1. First, add polyester resin, curing agent, carbon black, high-gloss additive, filler, antioxidant, and leveling agent to the mixer and mix for 15 minutes to obtain a mixture;

[0149] The high-speed mixing speed is 800 r / min;

[0150] S2. Then add the mixture obtained above into a dryer for drying;

[0151] The drying temperature is 60℃ and the drying time is 2 hours.

[0152] S3. Add the dried mixture to a twin-screw extruder and melt-extrude it;

[0153] S4. After being melt-extruded by a twin-screw extruder, the material is conveyed to a tablet press for tableting to obtain a sheet. The sheet is then crushed and sieved to obtain the finished black high-gloss polyester powder coating.

[0154] The black high-gloss polyester powder coating has an average particle size of 30μm.

[0155] Example 5

[0156] A black high-gloss polyester powder coating is made of the following components by weight: 94 parts polyester resin, 8 parts diaminophenyl sulfone, 3.2 parts carbon black, 0.8 parts high-gloss additive, 25 parts filler, 1.2 parts antioxidant 1010, and 2 parts polyacrylate.

[0157] The mass ratio of carbon black to high-gloss additive is 4:1.

[0158] The polyester resin used is di(2-ethylhexyl) phthalate.

[0159] The preparation method of the high-gloss additive is as follows:

[0160] (1) Add xylene to the reactor, and then add butyl acrylate, methyl methacrylate and graphene to the reactor in sequence. Stir and mix at 550 r / min for 20 min to obtain the base liquid.

[0161] (2) Add the initiator to xylene and stir at 500 r / min to mix evenly to obtain an initiator solution;

[0162] (3) The prepared initiator solution is added dropwise into the reaction vessel, and then the reaction is carried out at 80°C with stirring for 2 hours. First, a portion of xylene is removed by atmospheric distillation, and then the remaining xylene is removed by vacuum distillation. Finally, it is pulverized and then passed through a 500-mesh sieve to obtain the high-gloss additive.

[0163] Graphene after pre-modification treatment:

[0164] Graphene and maleic anhydride were added to a nitric acid solution, the temperature was adjusted to 60°C, and the mixture was stirred for 15 minutes. Then, the temperature was adjusted to 85°C, and the mixture was stirred for another 20 minutes. The mixture was then filtered, washed with water until neutral, and dried to constant weight to obtain preliminary graphene.

[0165] The preliminary graphene and cerium chloride obtained above were mixed evenly at a mass ratio of 1000:1, and then subjected to plasma treatment for 1 hour under a nitrogen atmosphere with a power of 300W. After discharge, the mixture was washed with a 50% ethanol solution, filtered, and dried to constant weight to complete the treatment.

[0166] The mass ratio of graphene, maleic anhydride, and nitric acid solution is 1:3:10.

[0167] The nitric acid solution has a mass fraction of 12%.

[0168] The drying temperature was 60℃ and the drying time was 40 minutes.

[0169] The mass ratio of xylene, butyl acrylate, methyl methacrylate, and graphene is 30:8:6:0.8.

[0170] The initiator is benzoyl peroxide;

[0171] The initiator solution has a mass fraction of 5%.

[0172] The initiator solution and base liquid are mixed in a mass ratio of 1:6; the filler is a mixture of titanium dioxide and calcium carbonate.

[0173] The mass ratio of titanium dioxide to calcium carbonate is 1:8.

[0174] A method for preparing a black high-gloss polyester powder coating includes the following steps:

[0175] S1. First, add polyester resin, curing agent, carbon black, high-gloss additive, filler, antioxidant, and leveling agent to the mixer and mix for 15 minutes to obtain a mixture;

[0176] The high-speed mixing speed is 800 r / min;

[0177] S2. Then add the mixture obtained above into a dryer for drying;

[0178] The drying temperature is 60℃ and the drying time is 2 hours.

[0179] S3. Add the dried mixture to a twin-screw extruder and melt-extrude it;

[0180] S4. After being melt-extruded by a twin-screw extruder, the material is conveyed to a tablet press for tableting to obtain a sheet. The sheet is then crushed and sieved to obtain the finished black high-gloss polyester powder coating.

[0181] The black high-gloss polyester powder coating has an average particle size of 30μm.

[0182] Comparative Example 1:

[0183] The difference from Example 1 is that no high-gloss additive is added, while the rest of the technical solutions remain the same.

[0184] test:

[0185] Test methods

[0186] The coatings from the examples and comparative examples were sprayed onto the surface of glass plates (10 plates per group, average value taken), with a thickness difference not exceeding 0.05 mm. After curing under the same conditions, the gloss of the coatings was measured according to ISO 2813.

[0187] Table 1

[0188]

[0189]

[0190] As can be seen from Table 1, the powder coating prepared by the present invention has a high gloss after curing.

[0191] The experiment continued by exposing the coated glass plates (ten per group, average value) to the intense light of a xenon lamp. Gloss was measured 2000 hours after initial exposure.

[0192] Gloss retention = (Gloss after test) / (Gloss before test) × 100%

[0193] Table 2

[0194] Gloss retention % Example 1 98 Example 2 98 Example 3 99 Example 4 98 Example 5 96 Comparative Example 1 58

[0195] As can be seen from Table 2, the coating formed by the powder coating prepared in this invention has relatively poor gloss retention.

[0196] The experiment continued, using Example 1 as the base sample, to compare the effect of different xenon lamp irradiation times on the gloss retention of the coating:

[0197] Table 3

[0198] Time / h Gloss retention % 0 100 1000 100 2000 98 4000 92 6000 88 8000 73

[0199] As can be seen from Table 3, the gloss retention of the coating formed by the coating of the present invention gradually decreases with the extension of strong light exposure time.

[0200] The above description is only a preferred embodiment of the present invention, but the present invention is not limited to the scope of implementation shown. Any changes made in accordance with the concept of the present invention, or equivalent embodiments modified to have equivalent changes, shall be within the protection scope of the present invention as long as they do not exceed the spirit covered by the specification.

Claims

1. A black high-gloss polyester powder coating, characterized in that, It is made of the following components by weight: 85-94 parts polyester resin, 6-8 parts curing agent, 2-3.2 parts carbon black, 0.5-0.8 parts high-gloss additive, 23-25 ​​parts filler, 1.2-0.8 parts antioxidant, and 1-2 parts leveling agent; The mass ratio of carbon black to high-gloss additive is 4:

1. The polyester resin used is an unsaturated polyester resin; The method for preparing the high-gloss additive is as follows: (1) Add organic solvent to the reactor, and then add butyl acrylate, methyl methacrylate and graphene to the reactor in sequence. Stir and mix at 550 r / min for 20 min to obtain the base liquid. (2) Add the initiator to the organic solvent and stir at 500 r / min to mix evenly to obtain an initiator solution; (3) The prepared initiator solution is added dropwise into the reaction vessel, and then the reaction is carried out at 80°C with stirring for 2 hours. First, a portion of the organic solvent is removed by atmospheric distillation, and then the remaining organic solvent is removed by vacuum distillation. Finally, the mixture is pulverized and then passed through a 500-mesh sieve to obtain the high-gloss additive. The graphene has undergone pre-modification treatment: Graphene and maleic anhydride were added to a nitric acid solution, the temperature was adjusted to 60°C, and the mixture was stirred for 15 minutes. Then, the temperature was adjusted to 85°C, and the mixture was stirred for another 20 minutes. The mixture was then filtered, washed with water until neutral, and dried to constant weight to obtain preliminary graphene. The preliminary graphene and cerium chloride obtained above were mixed evenly at a mass ratio of 1000:1, and then subjected to plasma treatment for 1 hour under a nitrogen atmosphere with a power of 300W. After discharge, the mixture was washed with a 50% ethanol solution, filtered, and dried to constant weight to complete the treatment. The mass ratio of graphene, maleic anhydride, and nitric acid solution is 1:3:

10. The nitric acid solution has a mass fraction of 12%. The drying temperature was 60℃ and the drying time was 40 minutes.

2. The black high-gloss polyester powder coating according to claim 1, characterized in that: The organic solvent is xylene; The mass ratio of xylene, butyl acrylate, methyl methacrylate, and graphene is 30:5-8:4-6:0.6-0.

8. The initiator is benzoyl peroxide; The initiator solution has a mass fraction of 5%. The mass ratio of the initiator solution to the base solution is 1:5-6.

3. The black high-gloss polyester powder coating according to claim 1, characterized in that: The curing agent is diaminophenyl sulfone.

4. The black high-gloss polyester powder coating according to claim 1, characterized in that: The filler is a mixture of titanium dioxide and calcium carbonate; The mass ratio of titanium dioxide to calcium carbonate is 1:

8.

5. The black high-gloss polyester powder coating according to claim 1, characterized in that: The antioxidant is antioxidant 1010.

6. The black high-gloss polyester powder coating according to claim 1, characterized in that: The leveling agent is polyacrylate.

7. The method for preparing a black high-gloss polyester powder coating according to claim 1, characterized in that, Includes the following steps: S1. First, add polyester resin, curing agent, carbon black, high-gloss additive, filler, antioxidant, and leveling agent to the mixer and mix for 15 minutes to obtain a mixture; The high-speed mixing speed is 800 r / min; S2. Then, the mixture obtained above is added to a dryer for drying. The drying temperature is 60℃ and the drying time is 2 hours. S3. Add the dried mixture to a twin-screw extruder and melt-extrude it; S4. After being melt-extruded by a twin-screw extruder, the material is conveyed to a tablet press for tableting to obtain a sheet. The sheet is then crushed and sieved to obtain the finished black high-gloss polyester powder coating. The black high-gloss polyester powder coating has an average particle size of 30μm.

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