High weatherable powder coating, method for preparing and use thereof

Abstract

The application belongs to the field of coating, and particularly discloses a kind of high weatherability powder coating and its preparation method and application;The powder coating includes the following weight parts of components: modified polyester resin 90-120 parts;Crystal polyester resin 10-20 parts;Acrylic resin 30-50 parts;Curing agent 19-35 parts;Pigment and filler 65-130 parts;Auxiliary agent 6-18 parts;The modified polyester resin is the carboxyl terminated polyester resin that is modified by using coupling agent modified nano SiO2 for modification treatment.The coating formed by the powder coating of the application has high crosslinking density and crosslinking strength, and the weatherability and mechanical properties of the coating are good, the coating has the properties of high and low temperature impact resistance, aging resistance, salt spray resistance, acid and alkali resistance, long service life, etc., and meets the use requirements of electrochemical energy storage power station.

Description

Technical Field

[0001] This invention belongs to the field of coatings, specifically relating to a high weather-resistant powder coating, its preparation method, and its application. Background Technology

[0002] Electrochemical energy storage power stations, as an important component of new energy technologies, have been widely applied. Their external coatings not only need excellent weather resistance but also must adapt to complex climatic conditions and chemical environments. Traditional powder coatings have certain limitations in weather resistance, especially under extreme climatic conditions such as high temperatures, ultraviolet radiation, and acid rain. Traditional coatings are prone to aging, fading, and peeling, making them unsuitable for electrochemical energy storage power station facilities that are exposed to the elements for extended periods. Therefore, developing a highly weather-resistant powder coating is of great significance for ensuring the long-term stable operation of energy storage power stations. Summary of the Invention

[0003] In order to overcome at least one of the technical problems existing in the prior art, one of the objectives of the present invention is to provide a powder coating.

[0004] The second objective of this invention is to provide a method for preparing powder coatings.

[0005] The third objective of this invention is to provide the application of the above-mentioned powder coating in electrochemical energy storage power stations, building exterior walls, or outdoor equipment.

[0006] To achieve the above objectives, the technical solution adopted by the present invention is as follows:

[0007] The first aspect of the present invention provides a powder coating comprising the following components in parts by weight: 90-120 parts of modified polyester resin; 10-20 parts of crystalline polyester resin; 30-50 parts of acrylic resin; 19-35 parts of curing agent; 65-130 parts of pigment and filler; and 6-18 parts of additives.

[0008] The modified polyester resin is a carboxyl-terminated polyester resin modified by using a coupling agent to modify nano-SiO2.

[0009] This invention uses a coupling agent to modify nano-SiO2 to modify carboxyl-terminated polyester resin, thereby obtaining a modified polyester resin with high weather resistance. When this modified polyester resin is combined with crystalline polyester resin and acrylic resin, it can significantly improve the powder coating's resistance to high and low temperature impact, aging, salt spray, acid and alkali, and other properties.

[0010] Preferably, the curing agent comprises the following components in parts by weight: 9-15 parts of triglycidyl isocyanurate; and 10-20 parts of dodecanoic acid. This invention employs a synergistic curing process using triglycidyl isocyanurate and dodecanoic acid. Dodecanoic acid can supplement the curing process. Compared to using a single curing agent, the synergistic curing effect is better, increasing the crosslinking density of the coating and thus improving its mechanical properties and weather resistance.

[0011] Preferably, the powder coating comprises the following components in parts by weight: 90-120 parts modified polyester resin; 10-20 parts crystalline polyester resin; 30-50 parts acrylic resin; 9-15 parts triglycidyl isocyanate; 10-20 parts dodecanoic acid; 65-130 parts pigments and fillers; and 6-18 parts additives.

[0012] Preferably, the additive is selected from at least one of leveling agents, brighteners, toughening agents, degassing agents, antioxidants, ultraviolet absorbers, and flame retardants.

[0013] Preferably, the additive comprises the following components in parts by weight: 2-4 parts leveling agent, 2-4 parts gloss agent, 1-5 parts toughening agent, and 1-5 parts degassing agent.

[0014] Preferably, the powder coating comprises the following components in parts by weight: 90-120 parts modified polyester resin; 10-20 parts crystalline polyester resin; 30-50 parts acrylic resin; 9-15 parts triglycidyl isocyanate; 10-20 parts dodecanoic acid; 65-130 parts pigments and fillers; 2-4 parts leveling agent; 2-4 parts gloss agent; 1-5 parts toughening agent; and 1-5 parts degassing agent. More preferably, the powder coating comprises the following components in parts by weight: 90-120 parts modified polyester resin; 10-20 parts crystalline polyester resin; 30-50 parts acrylic resin; and 9-15 parts triglycidyl isocyanate. The powder coating comprises, more preferably, the following components by weight: 90-120 parts modified polyester resin; 10-20 parts crystalline polyester resin; 30-50 parts acrylic resin; 9-15 parts triglycidyl isocyanate; 10-20 parts dodecanoic acid; 1-10 parts pigment; 5-20 parts titanium dioxide; 59-100 parts barium sulfate; 2-4 parts leveling agent; 2-4 parts gloss agent; 1-5 parts toughening agent; and 1-5 parts degassing agent.

[0015] Preferably, the D of the powder coating 50 The particle size is 35-45 μm; more preferably, the D of the powder coating is... 50 The particle size is 37-43 μm.

[0016] Preferably, the leveling agent is an acrylate leveling agent; more preferably, the leveling agent is selected from at least one of ethyl polyacrylate, butyl polyacrylate, and butyl acrylate-ethyl acrylate copolymer; more preferably, the leveling agent is selected from at least one of ethyl polyacrylate and butyl polyacrylate.

[0017] Preferably, the degassing agent is benzoin.

[0018] Preferably, the toughening agent is selected from at least one of AC-4030 (purchased from Danick Specialties & Support), M-732 (purchased from Kaneka Corporation, Japan), and EXL2620 (purchased from Dow Chemical Company).

[0019] Preferably, the pigment is selected from at least one of iron oxide red, iron oxide yellow, carbon black, ultramarine, iron yellow, phthalocyanine blue, and phthalocyanine green.

[0020] Preferably, the filler is selected from at least one of titanium dioxide, barium sulfate, nepheline powder, silica fume, and calcium carbonate; more preferably, the filler is selected from at least one of titanium dioxide and barium sulfate.

[0021] Preferably, the titanium dioxide is selected from at least one of rutile titanium dioxide and anatase titanium dioxide; more preferably, the titanium dioxide is rutile titanium dioxide.

[0022] Preferably, the modified polyester resin has an acid value of 30-45 mg KOH / g.

[0023] Preferably, the modified polyester resin has a hydroxyl value of 6-15 mg KOH / g.

[0024] Preferably, the modified polyester resin has a melt viscosity of 2800-3500 mPa·s measured at 200°C.

[0025] Preferably, the modified polyester resin has a Tg of 59–63°C.

[0026] Preferably, the crystal melting temperature of the crystalline polyester resin is 105–120°C.

[0027] Preferably, the acid value of the crystalline polyester resin is 28-36 mg KOH / g.

[0028] Preferably, the viscosity of the crystalline polyester resin measured at 125°C is 1400–1600 mPa·s.

[0029] In the powder coating of the present invention, the introduction of crystalline polyester resin can significantly improve the leveling and mechanical properties of the powder coating without affecting its weather resistance, so that the prepared powder coating has excellent weather resistance and good mechanical properties when applied to electrochemical energy storage power stations.

[0030] Preferably, the acrylic resin is selected from at least one of glycidyl acrylate resin, carboxyl acrylate resin, and hydroxyl acrylate resin; more preferably, the acrylic resin is selected from glycidyl acrylate resin. Glycidyl acrylate resin can be used as a crosslinking agent for carboxyl polyester resin to further increase the crosslinking density, and can also be used as a low-load reinforcing additive resin in polyester / TGIC or mixed systems, thereby forming a polyester / acrylic mixed curing system to increase the crosslinking density and give the coating excellent weather resistance and good mechanical properties.

[0031] Preferably, the acrylic resin has an epoxy equivalent of 480–530 g / eq and a glass transition temperature of 56–62 °C.

[0032] Preferably, the acrylic resin is selected from at least one of GMA-400G, GMA-500, and GMA-500G. GMA-400G, GMA-500, and GMA-500G are all purchased from Estron Chemical Company.

[0033] Preferably, the modified polyester resin is prepared by a method comprising the following steps:

[0034] A1: Mix polybasic acid and / or polybasic acid anhydride, polyol and catalyst and esterify at 240-250℃ for 3-4 hours to achieve an acid value of 20-50 KOH / g;

[0035] A2: Then react with antioxidants and polyacid end-capping agents at 220-235℃ to make the acid value reach 30-45KOH / g, and obtain carboxyl-terminated polyester resin;

[0036] A3: Melt the carboxyl-terminated polyester resin and then mix it with the coupling agent-modified nano-SiO2 to obtain the modified polyester resin.

[0037] In the process of synthesizing polyester resin, this invention mixes an antioxidant with the ester product obtained in step A1 and participates in the esterification reaction to improve the weather resistance of the polyester resin. After synthesizing carboxyl-terminated polyester resin, nano-SiO2 is modified by a coupling agent to change its hydrophilic properties to organic-philic properties, and then dispersed into the carboxyl-terminated polyester resin to achieve modification of the carboxyl-terminated polyester resin.

[0038] Preferably, step A1 is performed under inert gas protection.

[0039] Preferably, the inert gas is selected from at least one of nitrogen, argon, and helium.

[0040] Preferably, the modified polyester resin comprises the following raw materials in parts by weight: 45-55 parts neopentyl glycol, 15-20 parts 2-butyl-2-ethyl-1,3-propanediol, 1-10 parts trimethylolpropane, 80-90 parts isophthalic acid, 1-5 parts trimellitic anhydride, and 1-5 parts monobutyltin oxide. In this invention, isophthalic acid and trimellitic anhydride are used as raw materials for polybasic acids or polybasic anhydrides. Neopentyl glycol, 2-butyl-2-ethyl-1,3-propanediol, and trimethylolpropane are used as raw materials for polyols. Monobutyltin oxide is used as a catalyst. Isophthalic acid is also used as a polybasic acid end-capping agent.

[0041] Preferably, step A3 is performed under nitrogen pressure.

[0042] Preferably, the antioxidant is selected from at least one of hindered phenolic antioxidants and phosphite antioxidants; more preferably, the antioxidant is a mixture of hindered phenolic antioxidants and phosphite antioxidants; more preferably, the antioxidant is a mixture of hindered phenolic antioxidants and phosphite antioxidants in a mass ratio of 1:(3-5).

[0043] Preferably, the hindered phenolic antioxidant includes octadecyl 3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate.

[0044] Preferably, the phosphite antioxidant includes tris(2,4-di-tert-butylphenyl) phosphite.

[0045] Preferably, the antioxidant accounts for 0.1% to 1% of the total mass of the polyol and polyacid; more preferably, the antioxidant accounts for 0.4% to 0.7% of the total mass of the polyol and polyacid.

[0046] Preferably, the coupling agent modified nano-SiO2 is prepared by a method including the following steps: reacting the nano-SiO2 with a coupling agent by heating.

[0047] Preferably, the heating temperature is 100–130°C.

[0048] Preferably, the heating reaction time is 0.5 to 3 hours.

[0049] Preferably, the coupling agent is added to the reaction in two stages.

[0050] Preferably, the mass of the coupling agent is 0.5 to 1.5% of the mass of the nano-SiO2.

[0051] Preferably, the coupling agent modified nano-SiO2 is prepared by a method including the following steps: mixing nano-SiO2 with a portion of the coupling agent and solvent, heating to 90-110°C, adding the remaining coupling agent, heating to 120-130°C for reaction, and then filtering and washing to obtain the final product.

[0052] Preferably, the solvent is selected from toluene.

[0053] Preferably, the coupling agent is selected from at least one of silane coupling agents, phthalate coupling agents, and aluminate coupling agents; more preferably, the coupling agent is an aluminate coupling agent.

[0054] Preferably, the aluminate coupling agent is selected from DL-411-A and DL-411-B. Both DL-411-A and DL-411-B are purchased from Nanjing Pinning Coupling Agent Co., Ltd.

[0055] The second aspect of the present invention provides a method for preparing the powder coating provided in the first aspect of the present invention, comprising the following steps: mixing the raw materials and then sequentially extruding, pressing, pulverizing and sieving to obtain the powder coating.

[0056] Preferably, the extrusion step is performed using a twin-screw extruder.

[0057] Preferably, the temperature of zone I of the twin-screw extruder is 90-100°C and the temperature of zone II is 95-110°C; more preferably, the temperature of zone I of the twin-screw extruder is 90-95°C and the temperature of zone II is 100-105°C.

[0058] The third aspect of the invention provides the application of the powder coating described in the first aspect of the invention in electrochemical energy storage power stations, building exteriors, or outdoor equipment.

[0059] The beneficial effects of this invention are as follows: This invention uses weather-resistant modified polyester resin, crystalline polyester resin and acrylic resin to form a polyester / acrylic mixed curing system, which can make the coating have a high crosslinking density and crosslinking strength, thereby improving the weather resistance and mechanical properties of the coating. The coating can simultaneously have properties such as resistance to high and low temperature impact, aging resistance, salt spray resistance, acid and alkali resistance, and long service life, thereby meeting the high weather resistance and high mechanical performance requirements of electrochemical energy storage power stations. Detailed Implementation

[0060] The following examples provide a more detailed description of the specific implementation of the present invention, but the implementation and protection of the present invention are not limited thereto. It should be noted that any processes not specifically described below are methods that can be implemented or understood by those skilled in the art by referring to existing technology. Reagents or instruments whose manufacturers are not specified are all commercially available conventional products.

[0061] The information on the raw materials and instruments used in the embodiments and comparative examples of this invention is as follows:

[0062] Twin-screw extruder: JFY-30 crawler-type twin-screw extruder;

[0063] Crystalline polyester resin: SIR Industriale SpA PE 5900;

[0064] Common carboxyl-terminated polyester resin: NH3307, purchased from Qingtian Materials Technology Co., Ltd.;

[0065] Aluminate coupling agent: DL-411-A, purchased from Nanjing Pinning Coupling Agent Co., Ltd.;

[0066] Leveling agent: Acrylic leveling agent, BYK 360P from BYK Chemicals;

[0067] Brightener: GLP701, purchased from Ningbo Nanhai Chemical Co., Ltd.;

[0068] Degassing agents: Benzoin (benzoin), Estrogen;

[0069] Glycidyl acrylate resin: GMA500G from Estron Chemical;

[0070] Toughening agent: AC-4030, Danick Specialties & Support;

[0071] Pigment: at least one of iron oxide red, iron oxide yellow, carbon black, ultramarine, iron yellow, phthalocyanine blue, and phthalocyanine green;

[0072] Fillers: titanium dioxide and barium sulfate;

[0073] The modified polyester resin comprises the following raw materials in parts by weight: 50 parts neopentyl glycol, 18 parts 2-butyl-2-ethyl-1,3-propanediol, 5.5 parts trimethylolpropane, 85 parts isophthalic acid, 3.5 parts trimellitic anhydride, 2 parts monobutyltin oxide, and 1 part composite antioxidant.

[0074] The preparation method of modified polyester resin is as follows:

[0075] 67 parts by weight of isophthalic acid and the formulated amounts of trimellitic anhydride, neopentyl glycol, 2-butyl-2-ethyl-1,3-propane, trimethylolpropane, and catalyst (monobutyltin oxide) were added to a reactor. Nitrogen gas was introduced, and the temperature was gradually raised to 250°C. The reaction was maintained at this temperature for 3-4 hours, and the acid value was tested until it reached 20-50 mg KOH / g. The temperature was then lowered to 220°C, and a composite antioxidant and a polybasic acid end-capping agent (18 parts by weight of isophthalic acid) were added. The temperature was controlled at 220-230°C and maintained at this temperature. Vacuum was gradually evacuated until the acid value reached 30-45 mg KOH / g. The mixture was then cooled to room temperature and discharged to obtain polyester resin. The prepared polyester resin was placed in a mixing pot, heated to melt, and stirred at high speed until fully flowing. The nano-SiO2 modified by the coupling agent was slowly added at a rate of 0.5% of the mass of the polyester resin. The mixture was stirred thoroughly and uniformly. The mixture was then vacuumed and pressurized with nitrogen (pressure 2.5 MPa) for 1 hour before being discharged to obtain the modified polyester resin.

[0076] The compound antioxidant is prepared by mixing hindered phenolic antioxidant 3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate n-octadecyl alcohol ester and phosphite antioxidant tris(2,4-di-tert-butylphenyl) phosphite ester in a mass ratio of 1:4.

[0077] The preparation method of coupling agent modified nano-SiO2 is as follows:

[0078] Nano-SiO2 was dried at 105℃ for 1 hour to remove moisture from the powder. It was then placed in a three-necked flask, and a certain amount of toluene solution was added. 0.5% of the powder mass of aluminate coupling agent DL-411-A was slowly added. Stirring and ultrasonic oscillation were started, and the temperature was raised to 100℃. 0.5% of the powder mass of aluminate coupling agent was slowly added. Stirring and ultrasonic oscillation were started for 10 minutes. The temperature was raised to 120℃-130℃ and refluxed. The mixture was filtered, washed with anhydrous ethanol, and dried thoroughly in an oven to obtain coupling agent-modified nano-SiO2.

[0079] Example 1

[0080] This example provides a high weather-resistant powder coating for electrochemical energy storage power stations. The components of the powder coating and the weight parts of each component are shown in Table 1 below.

[0081] The high weather-resistant powder coating for electrochemical energy storage power stations in this example was prepared using a method including the following steps:

[0082] (1) By weight, place each component in a mixing tank, mix thoroughly and crush for 10 minutes to obtain a mixture;

[0083] (2) The mixture obtained in step (1) is melt-extruded using a twin-screw extruder. The temperature of zone I of the twin-screw extruder is 95°C and the temperature of zone II is 105°C. After being pressed into tablets by a tablet press, the mixture is cooled to 25±5°C, crushed, and sieved to obtain a high weather-resistant powder coating with a D50 particle size of 38μm for use in electrochemical energy storage power stations.

[0084] Example 2

[0085] This example provides a high weather-resistant powder coating for electrochemical energy storage power stations. The components of the powder coating and the weight parts of each component are shown in Table 1 below.

[0086] The high weather-resistant powder coating for electrochemical energy storage power stations in this example was prepared using a method including the following steps:

[0087] (1) By weight, place each component in a mixing tank, mix thoroughly and crush for 10 minutes to obtain a mixture;

[0088] (2) The mixture obtained in step (1) is melt-extruded using a twin-screw extruder. The temperature of zone I of the twin-screw extruder is 95°C and the temperature of zone II is 105°C. After being pressed into tablets by a tablet press, the mixture is cooled to 25±5°C, crushed, and sieved to obtain a high weather-resistant powder coating with a D50 particle size of 38μm for use in electrochemical energy storage power stations.

[0089] Example 3

[0090] This example provides a high weather-resistant powder coating for electrochemical energy storage power stations. The components of the powder coating and the weight parts of each component are shown in Table 1 below.

[0091] The high weather-resistant powder coating for electrochemical energy storage power stations in this example was prepared using a method including the following steps:

[0092] (1) By weight, place each component in a mixing tank, mix thoroughly and crush for 10 minutes to obtain a mixture;

[0093] (2) The mixture obtained in step (1) is melt-extruded using a twin-screw extruder. The temperature of zone I of the twin-screw extruder is 95°C and the temperature of zone II is 105°C. After being pressed into tablets by a tablet press, the mixture is cooled to 25±5°C, crushed, and sieved to obtain a high weather-resistant powder coating with a D50 particle size of 38μm for use in electrochemical energy storage power stations.

[0094] Example 4

[0095] This example provides a high weather-resistant powder coating for electrochemical energy storage power stations. The components of the powder coating and the weight parts of each component are shown in Table 1 below.

[0096] The high weather-resistant powder coating for electrochemical energy storage power stations in this example was prepared using a method including the following steps:

[0097] (1) By weight, place each component in a mixing tank, mix thoroughly and crush for 10 minutes to obtain a mixture;

[0098] (2) The mixture obtained in step (1) is melt-extruded using a twin-screw extruder. The temperature of zone I of the twin-screw extruder is 95°C and the temperature of zone II is 105°C. After being pressed into tablets by a tablet press, the mixture is cooled to 25±5°C, crushed, and sieved to obtain a high weather-resistant powder coating with a D50 particle size of 38μm for use in electrochemical energy storage power stations.

[0099] Table 1: Components and their weight parts of the powder coatings in Examples 1-4

[0100] Modified polyester resin 90 100 110 120 Crystalline polyester resin 10 15 15 20 Glycidyl Acrylic Resin 50 40 35 30 Titanium dioxide 10 15 15 20 Triglycidyl isocyanurate 8 9 11 12 Dodecanedioic acid 18 15 12 10 Leveling agent 3 3 3 3 Brightener 1.8 1.8 1.8 1.8 Degassing agent 2 2 2 2 toughening agent 7.5 7.5 7.5 7.5 Barium sulfate 80 85 85 100 pigment 2 2 2 2

[0101] Comparative Example 1

[0102] This example provides a powder coating for an electrochemical energy storage power station. The components of the powder coating and the weight parts of each component are shown in Table 2 below.

[0103] The powder coating used in this example for an electrochemical energy storage power station was prepared using a method that includes the following steps:

[0104] (1) By weight, place each component in a mixing tank, mix thoroughly and crush for 10 minutes to obtain a mixture;

[0105] (2) The mixture obtained in step (1) is melt-extruded using a twin-screw extruder. The temperature of zone I of the twin-screw extruder is 95°C and the temperature of zone II is 105°C. After being pressed into tablets by a tablet press, the mixture is cooled to 25±5°C, crushed, and sieved to obtain a powder coating with a D50 particle size of 38μm for use in electrochemical energy storage power stations.

[0106] The only difference between this example and Example 1 is that in this example, an equal amount of ordinary carboxyl-terminated polyester resin is used to replace the modified polyester resin in Example 1.

[0107] Comparative Example 2

[0108] This example provides a powder coating for an electrochemical energy storage power station. The components of the powder coating and the weight parts of each component are shown in Table 2 below.

[0109] The powder coating used in this example for an electrochemical energy storage power station was prepared using a method that includes the following steps:

[0110] (1) By weight, place each component in a mixing tank, mix thoroughly and crush for 10 minutes to obtain a mixture;

[0111] (2) The mixture obtained in step (1) is melt-extruded using a twin-screw extruder. The temperature of zone I of the twin-screw extruder is 95°C and the temperature of zone II is 105°C. After being pressed into tablets by a tablet press, the mixture is cooled to 25±5°C, crushed, and sieved to obtain a powder coating with a D50 particle size of 38μm for use in electrochemical energy storage power stations.

[0112] The only difference between this example and Example 2 is that in this example, an equal amount of ordinary carboxyl-terminated polyester resin is used to replace the crystalline polyester resin in Example 2.

[0113] Comparative Example 3

[0114] This example provides a powder coating for an electrochemical energy storage power station. The components of the powder coating and the weight parts of each component are shown in Table 2 below.

[0115] The powder coating used in this example for an electrochemical energy storage power station was prepared using a method that includes the following steps:

[0116] (1) By weight, place each component in a mixing tank, mix thoroughly and crush for 10 minutes to obtain a mixture;

[0117] (2) The mixture obtained in step (1) is melt-extruded using a twin-screw extruder. The temperature of zone I of the twin-screw extruder is 95°C and the temperature of zone II is 105°C. After being pressed into tablets by a tablet press, the mixture is cooled to 25±5°C, crushed, and sieved to obtain a powder coating with a D50 particle size of 38μm for use in electrochemical energy storage power stations.

[0118] The only difference between this example and Example 3 is that in this example, an equal amount of ordinary carboxyl-terminated polyester resin is used to replace the acrylic resin in Example 3.

[0119] Comparative Example 4

[0120] This example provides a powder coating for an electrochemical energy storage power station. The components of the powder coating and the weight parts of each component are shown in Table 2 below.

[0121] The powder coating used in this example for an electrochemical energy storage power station was prepared using a method that includes the following steps:

[0122] (1) By weight, place each component in a mixing tank, mix thoroughly and crush for 10 minutes to obtain a mixture;

[0123] (2) The mixture obtained in step (1) is melt-extruded using a twin-screw extruder. The temperature of zone I of the twin-screw extruder is 95°C and the temperature of zone II is 105°C. After being pressed into tablets by a tablet press, the mixture is cooled to 25±5°C, crushed, and sieved to obtain a powder coating with a D50 particle size of 38μm for use in electrochemical energy storage power stations.

[0124] The only difference between this example and Example 4 is that this example uses only triglycidyl isocyanurate as the curing agent for the system, without adding dodecanoic acid.

[0125] Table 2: Components and their weight parts of powder coatings in Comparative Examples 1-4

[0126] Modified polyester resin 0 100 110 120 Ordinary polyester resin 90 15 35 0 Crystalline polyester resin 10 0 15 20 Glycidyl Acrylic Resin 50 40 0 30 Titanium dioxide 10 15 15 20 Triglycidyl isocyanurate 8 9 11 15 Dodecanedioic acid 18 15 12 0 Leveling agent 3 3 3 3 Brightener 1.8 1.8 1.8 1.8 Degassing agent 2 2 2 2 toughening agent 7.5 7.5 7.5 7.5 Barium sulfate 80 85 85 100 pigment 2 2 2 2

[0127] Performance testing

[0128] Using a high-pressure electrostatic spray gun, the powder coatings prepared in Examples 1-4 and Comparative Examples 1-4 were sprayed onto the corresponding workpieces with a coating thickness of 100 μm. The workpieces were then placed in a high-temperature curing oven for curing at a temperature of 200°C for 10 min to obtain the coatings. Performance tests were then conducted, and the specific test results are shown in Table 3.

[0129] Table 3: Performance test results of powder coatings in Examples 1-4 and Comparative Examples 1-4

[0130]

[0131]

[0132]

[0133] As shown in Table 3, the powder coatings in Examples 1-4, after being applied to the substrate, exhibit good adhesion, thermal shock resistance, acid and alkali resistance, salt spray resistance, and aging resistance. Their excellent weather resistance and mechanical properties indicate that the powder coatings prepared in this invention can be used as topcoats for electrochemical energy storage power stations. In Comparative Example 1, where an equal amount of ordinary carboxyl-terminated polyester resin was used to replace the modified polyester resin, the resulting coating exhibited worse weather resistance than that of Example 1. In Comparative Example 2, where an equal amount of ordinary carboxyl-terminated polyester resin was used to replace the crystalline polyester resin, the resulting coating showed slightly poorer leveling properties and lower impact resistance than that of Example 2. In Comparative Example 3, where an equal amount of ordinary carboxyl-terminated polyester resin was used to replace the glycidyl acrylic resin, the resulting coating showed worse weather resistance and mechanical properties than that of Example 3. Comparative Example 4 used only triglycidyl isocyanurate as the curing agent for this system without adding dodecanoic acid. In this system, both the glycidyl acrylate resin and triglycidyl isocyanurate could crosslink and cure with the carboxyl groups in the polyester resin, but the resulting coating still had poor mechanical properties. In contrast, Example 4, by adding dodecanoic acid as a supplementary curing agent, greatly increased the crosslinking density of the coating, thereby improving its mechanical properties.

[0134] In summary, the film-forming substances of the powder coating of the present invention include modified polyester resin, crystalline polyester resin, and glycidyl acrylate resin; the curing agents include triglycidyl isocyanurate curing agent and dodecanoic acid curing agent, with dodecanoic acid playing a supplementary curing role; glycidyl acrylate resin can be used as a crosslinking agent for carboxylated polyester resin, or as a low-load reinforcing additive resin in polyester / TGIC or mixed systems, thereby forming a polyester / acrylate mixed curing system to improve crosslinking density and give the coating excellent weather resistance and good mechanical properties; the introduction of crystalline polyester resin into the powder coating can significantly improve leveling and mechanical properties without affecting weather resistance; the present invention uses modified polyester resin in combination with crystalline polyester resin, and by adding glycidyl acrylate resin, toughening agent, additives, etc., the prepared powder coating has excellent weather resistance and good mechanical properties, and can be applied to electrochemical energy storage power stations.

[0135] The embodiments of the present invention have been described in detail above. However, the present invention is not limited to the above embodiments. Within the scope of knowledge possessed by those skilled in the art, various changes can be made without departing from the spirit of the present invention. Furthermore, the embodiments of the present invention and the features thereof can be combined with each other unless otherwise specified.

Claims

1. A powder coating, characterized in that: The product comprises the following components in parts by weight: 90-120 parts modified polyester resin; 10-20 parts crystalline polyester resin; 30-50 parts acrylic resin; 19-35 parts curing agent; 65-130 parts pigments and fillers; and 6-18 parts additives. The modified polyester resin is a carboxyl-terminated polyester resin modified by using a coupling agent to modify nano-SiO2. The modified polyester resin has an acid value of 30-45 mg KOH / g; a hydroxyl value of 6-15 mg KOH / g; and a melt viscosity of 2800-3500 mPa·s measured at 200℃. The modified polyester resin has a Tg of 59~63℃; In the modified nano-SiO2 by the coupling agent, the coupling agent is an aluminate coupling agent; The curing agent comprises the following components in parts by weight: 9-15 parts of triglycidyl isocyanurate; 10-20 parts of dodecanoic acid; The additives include the following components in parts by weight: 2-4 parts leveling agent, 2-4 parts brightening agent, 1-5 parts toughening agent, and 1-5 parts degassing agent; The acrylic resin is a glycidyl acrylate resin; the epoxy equivalent of the acrylic resin is 480-530 g / eq, and the glass transition temperature is 56-62℃. The crystal melting temperature of the crystalline polyester resin is 105~120℃; the acid value of the crystalline polyester resin is 28~36mg KOH / g; and the viscosity of the crystalline polyester resin measured at 125℃ is 1400~1600 mPa.s. The modified polyester resin comprises the following raw materials in parts by weight: 45-55 parts neopentyl glycol, 15-20 parts 2-butyl-2-ethyl-1,3-propanediol, 1-10 parts trimethylolpropane, 80-90 parts isophthalic acid, 1-5 parts trimellitic anhydride, and 1-5 parts monobutyltin oxide; wherein, isophthalic acid is a polybasic acid and a polybasic acid end-capping agent; trimellitic anhydride is a polybasic acid anhydride; neopentyl glycol, 2-butyl-2-ethyl-1,3-propanediol, and trimethylolpropane are polyols, and monobutyltin oxide is a catalyst; The modified polyester resin is prepared by a method comprising the following steps: A1: After mixing polybasic acid, polybasic acid anhydride, polyol and catalyst, esterify at 240~250℃ for 3~4h to achieve an acid value of 20~50 KOH / g; A2: Then react with antioxidants and polyacid end-capping agents at 220~235℃ to make the acid value reach 30~45 KOH / g, and obtain carboxyl-terminated polyester resin; A3: Melt the carboxyl-terminated polyester resin and then mix it with the coupling agent-modified nano-SiO2 to obtain the modified polyester resin.

2. The powder coating according to claim 1, characterized in that: The coupling agent modified nano-SiO2 is prepared by a method including the following steps: reacting the nano-SiO2 with a coupling agent by heating.

3. The method for preparing powder coating according to any one of claims 1 to 2, characterized in that: Includes the following steps: The powder coating is prepared by mixing the raw materials and then sequentially extruding, pressing, crushing and sieving them.

4. The application of the powder coating according to any one of claims 1 to 2 in electrochemical energy storage power stations, building exterior walls or outdoor equipment.

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