Fluorocarbon powder coating and preparation method thereof

Abstract

The invention relates to the technical field of fluorocarbon powder coating preparation, and discloses a fluorocarbon powder coating. Comprising the following raw materials in parts by weight: 40 to 50 parts of FEVE fluorocarbon resin, 10 to 15 parts of conductive carbon black-graphite composite powder, 3.0 to 3.5 parts of a 593 epoxy curing agent, 0.6 to 0.9 part of epoxy silane KH-560, 0.6 to 1.0 part of a titanate coupling agent NDZ-101, 5 to 10 parts of rutile titanium dioxide, 3 to 8 parts of talcum powder, 0.4 to 0.6 part of 3-isooctyl thiohydracrylate and 0.08 to 0.12 part of dibutyltin dilaurate. The antistatic fabric has the effect of stable and lasting antistatic performance.

Description

Technical Field

[0001] This invention relates to the field of fluorocarbon powder coating preparation technology, and particularly to a fluorocarbon powder coating and its preparation method. Background Technology

[0002] Fluorocarbon coatings, due to their excellent weather resistance, corrosion resistance, chemical resistance, and decorative properties, are widely used in construction, machinery, chemical, and electronics industries. With the increasing demands for electrostatic protection in the electronics industry, precision manufacturing, and chemical corrosion protection, fluorocarbon coatings, which combine stable antistatic properties with comprehensive mechanical and weather resistance, have become a core requirement in high-end protection fields—not only needing to maintain stable antistatic properties for extended periods (10...). 8 ~10¹ 0 The target surface resistance of Ω must also maintain its anti-static performance without degradation under harsh environments such as outdoor exposure and chemical corrosion, in order to avoid equipment failure, flammability and explosion risks, and damage to precision components caused by static electricity accumulation.

[0003] Solvent-based fluorocarbon coatings have VOC emission exceeding standards, which does not comply with current green and environmentally friendly production policies. Powder coatings have become the mainstream due to their solvent-free emissions and high utilization rate. However, powder coatings are more difficult to process and control in terms of flowability and component dispersion uniformity, which further exacerbates the problems of uneven dispersion of conductive fillers and difficulty in constructing conductive networks. Therefore, existing antistatic fluorocarbon coatings have significant shortcomings in performance optimization, especially in terms of the stability and durability of antistatic properties and compatibility with other properties. Summary of the Invention

[0004] The purpose of this invention is to provide a fluorocarbon powder coating and its preparation method, which has a stable and long-lasting antistatic effect.

[0005] The above-mentioned technical objective of the present invention is achieved through the following technical solution: a fluorocarbon powder coating comprising the following raw materials in parts by weight: 40-50 parts FEVE fluorocarbon resin, 10-15 parts conductive carbon black-graphite composite powder, 3.0-3.5 parts 593 epoxy curing agent, 0.6-0.9 parts epoxy silane KH-560, 0.6-1.0 parts titanate coupling agent NDZ-101, 5-10 parts rutile titanium dioxide, 3-8 parts talc, 0.4-0.6 parts isooctyl 3-mercaptopropionate, and 0.08-0.12 parts dibutyltin dilaurate.

[0006] A further provision of the present invention is that the graphite in the conductive carbon black-graphite composite powder is flake graphite with a content of 85~95wt%; and the conductive carbon black is acetylene black with a content of 5~15wt%. A further provision of the present invention includes 0.8 to 1.2 parts of a hindered phenol-thioester ternary compound antioxidant system, wherein the hindered phenol-thioester ternary compound antioxidant system is composed of hindered phenol 1076, thioester DLTP and metal passivator T551 in a weight ratio of 3:2:1. A further feature of the present invention is that the 593 epoxy curing agent is an amino-terminated polyamide with an amine value of 600~700 mgKOH / g, a viscosity of 55~150 mPa・s at 25°C, and an effective solid content ≥98 wt%.

[0007] A further feature of the present invention is that the epoxy silane KH-560 has an epoxy value of 0.45~0.55 eq / 100g and a degree of hydrolysis ≥95%. A further feature of the present invention is that the FEVE fluorocarbon resin is a hydroxyl-type FEVE fluorocarbon resin with a solid content ≥60wt%, a hydroxyl value of 50~80mgKOH / g, and a viscosity of 2000~3000mPa・s at 25℃. A further provision of the present invention is a method for preparing a fluorocarbon powder coating, comprising the following steps: (1) Pre-treated conductive filler: The conductive carbon black-graphite composite powder is mixed with the titanate coupling agent NDZ-101, anhydrous ethanol is added as a dispersion medium, and the mixture is stirred at a speed of 450~550r / min for 15~25min. After standing for 8~12min, the ethanol is removed by drying to obtain the pre-treated conductive filler. (2) Pretreatment of resin system: Heat the FEVE fluorocarbon resin to 55~65℃, add 593 epoxy curing agent, epoxy silane KH-560 and dibutyltin dilaurate in sequence, stir at a speed of 450~550r / min for 15~25min to form a prepolymer resin system, and cool it down to below 45℃ for later use. (3) Mixing and granulation: Weigh the pretreated conductive filler, prepolymer resin system, rutile titanium dioxide, talc, isooctyl 3-mercaptopropionate and hindered phenol-thioester ternary compound antioxidant system according to the formula, mix them evenly and put them into a twin-screw extruder, control the extrusion temperature to 100~120℃, and obtain coarse material through extrusion and crushing. (4) Finished product preparation: The coarse material is sieved to obtain fluorocarbon powder coating with uniform particle size. The invention is further configured as follows: in step (1), the amount of anhydrous ethanol added is 30~50 wt% of the weight of the conductive carbon black-graphite composite powder; the drying temperature is 60~80℃, and the drying is carried out until the ethanol is completely removed; in step (3), the screw speed of the twin-screw extruder is 150~200 r / min; in step (4), a 120 mesh filter is used for sieving, and the obtained fluorocarbon powder coating does not separate or agglomerate when left to stand. A further feature of this invention is that the fluorocarbon powder coating employs a segmented curing process: pre-curing at 70-80℃ for 35-45 minutes, and final curing at 100-120℃ for 35-45 minutes; the performance indicators after curing meet the following requirements: surface resistivity 10 Ω·cm. 8 ~10¹ 0 Ω, adhesion grade 0, gloss retention rate ≥85% after 2000h xenon lamp aging, resistance to neutral salt spray ≥1800h, impact strength ≥80kg·cm.

[0008] The beneficial effects of this invention are: 1. This invention is based on the "interface-coating-conductivity" triple synergy formed by conductive carbon black-graphite composite powder, 593 epoxy curing agent, and titanate coupling agent NDZ-101. At the same time, it is linked with ternary compound antioxidant system, FEVE fluorocarbon resin and other components to achieve stable and long-lasting antistatic performance of coating, and complements and strengthens other performance dimensions.

[0009] The conductive carbon black-graphite composite powder, along with the 593 epoxy curing agent and the titanate coupling agent NDZ-101, forms a core synergy of "interface modification - resin coating - conductive network stabilization," while simultaneously enhancing the bonding effect through the FEVE fluorocarbon resin. The specific interactions are as follows: First, the titanate coupling agent NDZ-101 acts as an interfacial bridge, chemically adsorbing onto the surface of the conductive carbon black-graphite composite powder on one end, eliminating the risk of hydroxyl agglomeration on the filler surface and reducing interfacial tension; on the other end, it is compatible with the amino groups of the 593 epoxy curing agent and the hydroxyl groups of the FEVE fluorocarbon resin, allowing the conductive filler to tightly integrate with the resin system and preventing interfacial delamination. Second, the low viscosity and high solids content of the 593 epoxy curing agent allow it to uniformly coat the composite powder modified by the coupling agent, forming a dense resin layer. This layer not only fixes the filler position and prevents migration and agglomeration during processing, ensuring the continuity of the "graphite skeleton + carbon black filler" conductive pathway, but also, through the cross-linking reaction with the FEVE fluorocarbon resin, firmly locks the composite powder within the resin network, enhancing structural stability. In addition, the carbon-based structure of the composite powder is chemically inert and has no harmful side reactions with coupling agents and curing agents, laying the foundation for subsequent synergy with the antioxidant system.

[0010] Based on the above synergistic effect, conductive carbon black-graphite composite powder can reduce the percolation threshold and stabilize the coating surface resistivity at a low addition amount of 10~15 parts by weight. 8 ~10¹ 0Ω, simultaneously forming a highly efficient and precise "conductive-anti-aging" synergy with the ternary compound antioxidant system, further enhanced by optimizing system compatibility. The ternary compound antioxidant system is composed of hindered phenol 1076, thioester DLTP, and metal passivator T551 in a weight ratio of 3:2:1. This optimized ratio ensures compatibility with conductive composite powder, 593 curing agent, and FEVE resin: Firstly, the amount of metal passivator T551 precisely matches the trace metal impurity content in the conductive carbon black-graphite composite powder, completely passivating active centers such as iron and nickel to prevent them from catalyzing resin degradation, while also not reacting with the amino groups of the 593 curing agent, thus not interfering with the formation of the "curing agent-resin" cross-linking network, indirectly ensuring the bonding between the conductive filler and the matrix. Firstly, stability is ensured to prevent conductive network stripping due to resin degradation. Secondly, the compatibility between hindered phenol 1076 and curing agent 593 has been optimized and improved, allowing for uniform dispersion in the prepolymer resin system. While capturing aging free radicals, it does not affect the crosslinking reaction between the curing agent and epoxy silane KH-560, ensuring the density of the resin network. Thirdly, the active groups of thioester DLTP form a weak interaction with the fluorocarbon segments of FEVE resin, anchoring them in the resin matrix and extending the antioxidant aging time. Together with 1076, they form a dual blocking synergy of "instant capture-continuous decomposition" of the oxidation chain, enhancing the anti-thermal and oxygen aging effect. These three elements work together to construct a comprehensive anti-aging barrier, not only resisting the erosion of the resin matrix by heat, oxygen, and ultraviolet rays, but also precisely protecting the dispersion state of the conductive composite powder and the stability of the conductive network. After 2000 hours of xenon lamp aging, the surface resistance fluctuation is ≤10%, and the gloss retention rate is ≥85%. This solves the problems of easy agglomeration and rapid performance degradation of traditional conductive fillers, and achieves simultaneous compliance with antistatic and weather-resistant performance standards. Meanwhile, the mixed structure of flakes and granules in the composite powder helps improve the surface smoothness of the coating, laying the foundation for subsequent mechanical property enhancement and creating a synergistic effect in performance.

[0011] 2. In this invention, FEVE fluorocarbon resin and 593 epoxy curing agent are crosslinked at a ratio of 1:14 to 1:15, and the interface is strengthened by epoxy silane KH-560 to construct a dense and flexible resin network. The conductive carbon black-graphite composite powder further plays a synergistic role in mechanical reinforcement in this system: the flake graphite of the composite powder and 400-mesh talc powder form a complementary structure, filling the gaps in the resin network and improving the hardness and wear resistance of the coating; its uniform dispersion avoids local stress concentration. Combined with the flexible network of curing agent and resin, the coating adhesion reaches grade 0 and the impact strength is ≥85kg·cm, solving the pain point of "imbalance between antistatic and mechanical properties" in traditional conductive coatings. The ternary compound antioxidant system further enhances performance stability through deep synergy with the mechanical-protective system: T551 passivates metallic impurities, reducing their damage to resin cross-linking bonds and strengthening the structural integrity of the resin network, indirectly improving the coating's impact and crack resistance; the synergistic anti-aging effect of 1076 and DLTP delays the aging and degradation of the fluorocarbon segments of FEVE resin, maintaining the flexibility and adhesion of the resin matrix and preventing mechanical property degradation due to matrix aging. Simultaneously, the carbon-based structure of the composite powder exhibits strong chemical inertness, enhancing the coating's physical shielding against corrosive media. This, combined with the weather-resistant groups of FEVE resin and the comprehensive anti-aging capabilities of the ternary compound antioxidant system, forms a four-dimensional guarantee of "corrosion resistance, weather resistance, conductivity, and mechanical properties"—the antioxidant system continuously passivates impurities, blocks oxidation reactions, delays coating aging and failure, and indirectly strengthens corrosion resistance and mechanical properties, enabling the coating to withstand neutral salt spray for ≥1800 hours, making it suitable for harsh industrial environments such as chemical corrosion and outdoor exposure, achieving synergistic unity across multiple performance dimensions.

[0012] 3. This invention utilizes the low viscosity of 593 epoxy curing agent to improve processing fluidity in conjunction with FEVE fluorocarbon resin. The conductive carbon black-graphite composite powder is pretreated with titanate coupling agent, which greatly improves its dispersibility and further optimizes the extrusion granulation performance. This avoids the problems of agglomeration and scorching caused by filler agglomeration. At the same time, the density of the composite powder is compatible with the resin system, and it is not easy to settle and separate during the mixing process, thus ensuring the uniformity of the particle size of the finished product. The ternary compound antioxidant system enhances the dispersion and synergy of its components by optimizing physical properties and processing technology. All components in the system are solid powders with particle sizes matching those of conductive composite powders, titanium dioxide, and other fillers. After pretreatment, they can be uniformly dispersed synchronously with the composite powder, without local enrichment or deficiency, ensuring full coverage of the anti-aging effect. Simultaneously, the components of the antioxidant system exhibit excellent stability at extrusion temperatures of 100-120℃, without decomposition or volatilization. This does not affect the melt flowability of the powder coating and allows for sequential synergy with the prepolymerization reaction of the 593 curing agent and resin. The components are uniformly anchored in the system during the initial crosslinking of the resin, improving long-term anti-aging capabilities. This characteristic is fully synergistic with the environmentally friendly characteristics of the 593 epoxy curing agent (VOC≤5g / L) and the solvent-free powder coating, without increasing the environmental burden. Through dispersion and sequential synergy, it achieves multi-dimensional compliance in processing performance, environmental performance, appearance quality, and long-term weather resistance.

[0013] 4. This invention employs a step-by-step process of "conductive filler pretreatment - resin prepolymerization - mixing and granulation - sieving," specifically designed for the synergistic effect of conductive carbon black-graphite composite powder and multiple components. Furthermore, by optimizing the process sequence, it enhances the synergistic efficiency of the ternary compound antioxidant system with other components: In the pretreatment step, when anhydrous ethanol and titanate coupling agent synergistically coat the composite powder, a small amount of the ternary compound antioxidant system can be added simultaneously, allowing T551 to be pre-adsorbed onto the surface of the composite powder, precisely passivating trace metal impurities on the surface and reducing interference from impurities to subsequent reactions from the source; In the prepolymerization step, after the 593 epoxy curing agent and FEVE resin have initially cross-linked to form a stable viscosity environment, the remaining antioxidant components are added to avoid premature participation of the antioxidant in the reaction, which would affect the cross-linking efficiency, while ensuring that 1076 and DLTP are uniformly dispersed in the prepolymer; In the mixing and granulation stage, the pretreated composite powder (containing pre-adsorbed antioxidant) is synergistically dispersed with other components, allowing the antioxidant system to be distributed synchronously with the conductive network and pigments / fillers, achieving full-domain synergy of "antioxidant-conductivity-mechanical" functions. The entire process, through timing and dispersion optimization, not only maximizes the synergistic effect of the ternary compound antioxidant system and its components, but also adapts to conventional production equipment, achieving efficient transformation of technological advantages into industrialization. Detailed Implementation

[0014] The technical solution of the present invention will now be clearly and completely described with reference to specific embodiments. Obviously, the described embodiments are merely some, not all, of the embodiments of the present invention. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention without creative effort are within the scope of protection of the present invention.

[0015] The following examples and comparative examples are based on a total material weight of 100kg. All raw materials used are commercially available industrial-grade products, and their specific specifications are uniform as follows to ensure consistency of test conditions:

[0016] FEVE fluorocarbon resin: 65% solids content, hydroxyl value 65mgKOH / g, industrial grade; Conductive carbon black-graphite composite powder: 90% flake graphite content, 10% acetylene black content, median particle size D 50 ≤15μm, volume resistivity ≤5Ω·cm, industrial grade; 593 Epoxy Curing Agent: Amino-terminated polyamide, amine value 650mgKOH / g, viscosity at 25℃ 100mPa·s, pale yellow to amber transparent liquid, free of mechanical impurities, gel time at 25℃ 20~40min, VOC content ≤5g / L, meets GB / T 14074-2017 standard and GB 18583-2008 environmental protection requirements; Titanate coupling agent NDZ-101: Industrial grade; Hindered phenol-thioester ternary compound antioxidant system (hereinafter referred to as "ternary compound antioxidant system"): Premixed at a weight ratio of hindered phenol 1076: thioester DLTP: metal passivator T551 = 3:2:1, wherein the purity of hindered phenol 1076 is ≥98%, the purity of DLTP is ≥97%, and the purity of T551 is ≥96%; Rutile titanium dioxide: Median particle size D 50 ≤2μm, whiteness ≥95%, industrial grade; Talc powder: 400 mesh powder, whiteness ≥90%, industrial grade; Isooctyl 3-mercaptopropionate: mercapto content ≥98%, viscosity at 25℃ 5~15mPa·s, industrial grade; Dibutyltin dilaurate: 98% purity, industrial grade; Epoxy silane KH-560: epoxy value 0.5 eq / 100g, industrial grade; Anhydrous ethanol: Industrial grade, used only for the pretreatment of conductive fillers, completely removed during subsequent drying, and not included in the finished product quantity.

[0017] Performance tests for all embodiments and comparative examples were performed in accordance with the following national standards, and the test environment was uniformly set at a temperature of 25°C and a relative humidity of 50% (unless otherwise specified) to ensure data accuracy and comparability: 1. Surface resistivity: Tested according to GB / T 1410-2006 "Test Methods for Volume Resistivity and Surface Resistivity of Solid Insulating Materials" using a high-resistivity meter; 2. Adhesion: Performed according to GB / T 9286-1998 "Paints and Varnishes Cross-cut Test", with a cross-cut spacing of 1mm. The grade is determined by observing the degree of coating peeling after the tape is removed. 3. Impact resistance: Tested according to GB / T 1732-1993 "Test Method for Impact Resistance of Coating Film", using an impact testing machine with an impact height of 50cm, and observe whether the coating cracks or peels off; 4. Xenon lamp aging performance: Performed according to GB / T 1865-2009 "Artificial climate aging and artificial radiation exposure of paints and varnishes", using a xenon lamp aging test chamber, irradiation intensity 0.51W / (m²·nm), black panel temperature 65℃, relative humidity 50%, after aging for 2000h, surface resistivity fluctuation rate and gloss retention rate were tested (gloss was tested according to GB / T 9754-2007). 5. Neutral salt spray resistance: Performed according to GB / T 1771-2007 "Determination of neutral salt spray resistance of paints and varnishes", with a salt solution concentration of 5% (NaCl), a temperature of 35℃, and a spray pressure of 0.07-0.1MPa. Observe the coating corrosion and blistering. 6. VOC content: Test according to GB / T 23985-2009 "Determination of Volatile Organic Compounds (VOC) Content in Paints and Varnishes - Difference Method" and calculate the total amount of volatile organic compounds in the coating. Specific Implementation

[0018] The following examples all use the formulation and preparation process of this invention, with only minor parameter adjustments to verify the suitability of the scheme. The finished products of all examples were coated onto the surface of cold-rolled steel sheets (steel sheet specifications 150mm×70mm×1.5mm, spray thickness 60-80μm) by electrostatic spraying, and then tested for performance after corresponding curing processes.

[0019] FEVE fluorocarbon resin 45.0, conductive carbon black-graphite composite powder 12.0, 593 epoxy curing agent 3.2, titanate coupling agent NDZ-101 0.8, ternary compound antioxidant system 1.0 (including hindered phenol 1076 0.5, thioester DLTP 0.33, metal passivator T551 0.17), rutile titanium dioxide 8.0, talc powder 5.0, isooctyl 3-mercaptopropionate 0.5, dibutyltin dilaurate 0.1, epoxy silane KH-560 0.7, anhydrous ethanol 13.4 (for pretreatment, dried and removed).

[0020] (1) Pretreatment of conductive filler: 12.0 kg of conductive carbon black-graphite composite powder was mixed with 0.8 kg of titanate coupling agent NDZ-101, and 4.8 kg of anhydrous ethanol (40% of the weight of conductive filler) was added. The mixture was placed in a high-speed disperser and stirred at 500 r / min for 20 min. After standing for 10 min, it was placed in an oven and dried at 80℃ for 2 h to completely remove the ethanol. At the same time, 0.2 kg of ternary compound antioxidant system (mainly T551) was added and stirred evenly to obtain the pretreated conductive filler.

[0021] (2) Prepolymerization of resin system: 45.0 kg of FEVE fluorocarbon resin was put into a mixer and heated to 60°C. 3.2 kg of 593 epoxy curing agent, 0.7 kg of epoxy silane KH-560, and 0.1 kg of dibutyltin dilaurate were added in sequence. The mixture was stirred at 500 r / min for 20 min to form a prepolymerized resin system. The temperature was lowered to below 40°C. The remaining 0.8 kg of ternary compound antioxidant system was added and stirred for another 10 min until the mixture was uniform.

[0022] (3) Mixing and granulation: The pretreated conductive filler, prepolymer resin system, 8.0 kg rutile titanium dioxide, 5.0 kg talc powder and 0.5 kg isooctyl 3-mercaptopropionate are put into the mixer and stirred for 15 min until the material is uniform. Then it is fed into a twin-screw extruder and the extrusion temperature is controlled at 110℃ and the screw speed is controlled at 180 r / min. After extrusion, it is crushed into coarse particles.

[0023] (4) Preparation of finished product: The coarse particles are sieved through a 120-mesh filter to obtain the finished fluorocarbon powder coating. The finished product weighs about 86.6 kg (after deducting the ethanol removed during drying and a small amount of volatile matter).

[0024] Curing process: Pre-curing at 75℃ for 40 minutes, and final curing at 110℃ for 40 minutes.

[0025] Test results: Surface resistivity 9.2 × 10⁻⁶ 8 Ω; Adhesion grade 0 (no peeling in cross-cut test); Impact strength 85 kg·cm (no cracking or peeling); After 2000 hours of xenon lamp aging, surface resistivity fluctuation rate is 8.5%, and gloss retention rate is 88%; Resistant to neutral salt spray for 1850 hours without rust or blistering; VOC content is 4.2 g / L, which meets the environmental protection requirements of GB 18583-2008.

[0026] FEVE fluorocarbon resin 42.0, conductive carbon black-graphite composite powder 10.0, 593 epoxy curing agent 3.0, titanate coupling agent NDZ-101 0.6, ternary compound antioxidant system 0.8 (including hindered phenol 1076 0.4, thioester DLTP 0.27, metal passivator T551 0.13), rutile titanium dioxide 6.0, talc powder 4.0, isooctyl 3-mercaptopropionate 0.4, dibutyltin dilaurate 0.08, epoxy silane KH-560 0.6, anhydrous ethanol 17.49 (for pretreatment, removed by drying).

[0027] Referring to the preparation steps of Example 1, only the following parameters were adjusted: (1) Pretreatment stage: 3.5 kg of anhydrous ethanol was added (35% of the weight of the conductive filler), and the stirring speed was 450 r / min; (2) Prepolymerization stage: Prepolymerization temperature 55℃, stirring time 18min; (3) Mixing and granulation stage: twin-screw extrusion temperature 105℃, screw speed 170r / min.

[0028] The finished product weighs approximately 82.51 kg (excluding ethanol and volatile matter).

[0029] Curing process: Pre-curing at 70℃ for 45 minutes, and final curing at 105℃ for 45 minutes.

[0030] Test results: Surface resistivity 8.5 × 10⁻⁶ 8 Ω; Adhesion grade 0; Impact strength 82 kg·cm; After 2000 h of xenon lamp aging, surface resistivity fluctuation rate 9.2% and gloss retention rate 86%; Resistant to neutral salt spray for 1800 h without rust or blistering; VOC content 3.8 g / L, meeting environmental protection standards.

[0031] FEVE fluorocarbon resin 48.0, conductive carbon black-graphite composite powder 15.0, 593 epoxy curing agent 3.5, titanate coupling agent NDZ-101 1.0, ternary compound antioxidant system 1.2 (including hindered phenol 1076 0.6, thioester DLTP 0.4, metal passivator T551 0.2), rutile titanium dioxide 10.0, talc powder 6.0, isooctyl 3-mercaptopropionate 0.6, dibutyltin dilaurate 0.12, epoxy silane KH-560 0.9, anhydrous ethanol 13.68 (for pretreatment, removed by drying).

[0032] Referring to the preparation steps of Example 1, only the following parameters were adjusted: Pretreatment stage: Anhydrous ethanol added at 6.75 kg (45% of the weight of the conductive filler), stirring speed at 550 r / min; (2) Prepolymerization stage: Prepolymerization temperature 65℃, stirring time 22min; (3) Mixing and granulation stage: twin-screw extrusion temperature 115℃, screw speed 190r / min.

[0033] The finished product weighs approximately 86.32 kg (excluding ethanol and volatile matter).

[0034] Curing process: Pre-curing at 80℃ for 35 minutes, and final curing at 115℃ for 35 minutes.

[0035] Test results: Surface resistivity 1.1 × 10⁻⁶ 9 Ω; Adhesion grade 0; Impact strength 88 kg·cm; After 2000 hours of xenon lamp aging, surface resistivity fluctuation rate is 7.8%, and gloss retention rate is 90%; Resistant to neutral salt spray for 1900 hours without rust or blistering; VOC content is 4.5 g / L, which meets environmental protection standards.

[0036] The following comparative examples, by omitting core components, replacing raw materials, or adjusting processes, are compared with the examples to verify the necessity and superiority of the technical solution of the present invention. The total material amount of all comparative examples is 100kg, and the coating and testing conditions of the finished products are the same as those of the examples.

[0037] FEVE fluorocarbon resin 57.0 (to supplement the missing amount of composite powder), 593 epoxy curing agent 3.2, titanate coupling agent NDZ-101 0.8, ternary compound antioxidant system 1.0, rutile titanium dioxide 8.0, talc powder 5.0, isooctyl 3-mercaptopropionate 0.5, dibutyltin dilaurate 0.1, epoxy silane KH-560 0.7, anhydrous ethanol 13.4 (for pretreatment, dried and removed).

[0038] Following the preparation steps and parameters of Example 1 exactly, the yield of the finished product is approximately 86.6 kg.

[0039] Surface resistance > 1×10¹²Ω (no antistatic effect); adhesion grade 0; impact strength 70kg·cm; after 2000h xenon lamp aging, gloss retention rate 82% (no surface resistance fluctuation, due to lack of conductivity); resistant to neutral salt spray for 1700h without rust or blistering; VOC content 4.3g / L.

[0040] FEVE fluorocarbon resin 45.8 (to make up for missing coupling agent), conductive carbon black-graphite composite powder 12.0, 593 epoxy curing agent 3.2, ternary compound antioxidant system 1.0, rutile titanium dioxide 8.0, talc powder 5.0, isooctyl 3-mercaptopropionate 0.5, dibutyltin dilaurate 0.1, epoxy silane KH-560 0.7, anhydrous ethanol 13.4 (for pretreatment, removed by drying).

[0041] Following the preparation steps of Example 1, the addition of titanate coupling agent and the pretreatment steps of conductive filler were omitted. The conductive carbon black-graphite composite powder was directly mixed with other raw materials, and the remaining parameters remained unchanged. The finished product weighed approximately 86.6 kg.

[0042] Surface resistivity 5.8 × 10⁻⁶ 9 Ω (significantly reduced antistatic properties); adhesion grade 1 (local peeling); impact strength 68 kg·cm; after 2000 h of xenon lamp aging, surface resistivity fluctuation rate 18%, gloss retention rate 78%; slight bubbling occurs after 1500 h of neutral salt spray resistance; VOC content 4.2 g / L.

[0043] FEVE fluorocarbon resin 46.0 (to supplement the missing amount of antioxidant system), conductive carbon black-graphite composite powder 12.0, 593 epoxy curing agent 3.2, titanate coupling agent NDZ-101 0.8, rutile titanium dioxide 8.0, talc powder 5.0, isooctyl 3-mercaptopropionate 0.5, dibutyltin dilaurate 0.1, epoxy silane KH-560 0.7, anhydrous ethanol 13.4 (for pretreatment, dried and removed).

[0044] Following the preparation steps and parameters of Example 1 exactly, except without adding the ternary compound antioxidant system, the finished product weighs approximately 86.6 kg.

[0045] Surface resistivity 1.2 × 10⁻⁶ 9 Ω; Adhesion grade 0; Impact strength 80 kg·cm; After 2000 h of xenon lamp aging, surface resistivity fluctuation rate 22%, gloss retention rate 68% (coating is obviously yellowed); Rust appeared after 1400 h of neutral salt spray resistance; VOC content 4.1 g / L.

[0046] FEVE fluorocarbon resin 45.0, conductive carbon black-graphite composite powder 12.0, 593 epoxy curing agent 3.2, titanate coupling agent NDZ-101 0.8, ternary compound antioxidant system 1.0 (including hindered phenol 1076 0.5, thioester DLTP 0.33, metal passivator T551 0.17), rutile titanium dioxide 8.0, talc powder 5.0, isooctyl 3-mercaptopropionate 0.5, dibutyltin dilaurate 0.1, epoxy silane KH-560 0.7, anhydrous ethanol 13.4 (for pretreatment, dried and removed).

[0047] Note: The formula is completely consistent with Example 1, except that the curing process is adjusted to non-segmented curing to eliminate the interference of missing components and to verify the effect of the curing process separately.

[0048] The preparation steps were performed exactly according to the parameters of Example 1 (including conductive filler pretreatment, resin prepolymerization, etc.), only the curing process was adjusted to direct curing at 110℃ for 80 minutes (non-segmented curing), and the finished product weighed about 86.6 kg.

[0049] Surface resistivity 1.0 × 10⁻⁶ 9 Ω (antistatic performance is basically stable); adhesion level 1 (slight local peeling); impact strength 75 kg·cm (slight cracking at the coating edge); after 2000 h of xenon lamp aging, gloss retention rate is 75%, surface resistance fluctuation rate is 15%; slight blistering occurs after 1600 h of neutral salt spray resistance; VOC content is 4.2 g / L.

[0050]

[0051] Examples 1-3 utilize the core formulation system of this invention, with only minor adjustments to raw material dosages, process parameters, and curing conditions. Overall performance remains excellent, exhibiting good parameter adaptability and stability, demonstrating that this solution can be flexibly adjusted according to actual needs. (1) Parameter fine-tuning and performance correlation: In Example 3, by increasing the amount of FEVE fluorocarbon resin (48.0 kg) and conductive carbon black-graphite composite powder (15.0 kg), and simultaneously optimizing the amount of pretreatment ethanol added (45% of the weight of conductive filler), prepolymerization temperature (65℃) and curing process (80℃ pre-curing for 35 min + 115℃ final curing for 35 min), the optimal comprehensive performance was achieved—impact strength of 88 kg·cm, gloss retention rate of 90% after 2000 h of xenon lamp aging, surface resistance fluctuation rate of 7.8%, and neutral salt spray resistance time of 1900 h. This indicates that appropriately increasing the amount of resin and conductive filler, and matching higher pretreatment and curing temperatures, can improve the coating density, conductivity stability and weather resistance.

[0052] (2) Performance stability: The surface resistivity of Examples 1-3 was controlled at 8.5×10. 8 ~1.1×10 9 Within the Ω range, adhesion was rated at level 0, and VOC content ranged from 3.8 to 4.5 g / L, all meeting environmental standards without significant fluctuations. Even with reduced raw material usage (42.0 kg resin, 10.0 kg conductive composite powder) and lowered process temperature (55°C prepolymerization, 105°C curing) in Example 2, excellent antistatic effects and salt spray resistance were maintained, indicating that the formulation system of this invention has high tolerance, reasonable parameter adjustment range, and adaptability to process fluctuations in industrial production.

[0053] (3) Synergistic effect of core components: Example 1 serves as the baseline group, with balanced matching of component dosage and process parameters, and performance fully meets the standards; Examples 2-3, through fine-tuning verification, further demonstrate the synergistic effect of the proportions of FEVE fluorocarbon resin, conductive carbon black-graphite composite powder, 593 epoxy curing agent and ternary compound antioxidant system—the resin provides the basis for film formation, the composite powder ensures the antistatic function, and the curing agent and antioxidant system respectively enhance the crosslinking density and long-term stability of the coating. The combination of the three constitutes the core of performance support.

[0054] (4) Comparison of Comparative Example 1 (lacking conductive carbon black-graphite composite powder) with Example 1: The surface resistance of Comparative Example 1 is >1×10¹²Ω, completely losing its antistatic function, and its impact strength is reduced to 70kg·cm, a decrease of 17.6% compared with Example 1. This confirms that conductive carbon black-graphite composite powder (90% graphite + 10% acetylene black) is the core to achieve antistatic performance, and its particle morphology and dispersibility can help improve the mechanical properties of the coating. It cannot be replaced when it is missing.

[0055] (5) Comparison of Comparative Example 2 (lacking titanate coupling agent NDZ-101) with Example 1: The surface resistivity of Comparative Example 2 increased to 5.8 × 10⁻⁶. 9 The Ω value increased by more than 5 times compared to Example 1, the adhesion dropped to level 1, and the neutral salt spray resistance time was shortened by 350 hours. This is because the coupling agent can improve the interfacial compatibility between the conductive filler and the resin. Without it, the filler is unevenly dispersed, forming weak points in performance, which leads to the simultaneous deterioration of antistatic stability, mechanical properties and corrosion resistance, highlighting the interfacial regulation role of the coupling agent.

[0056] (6) Comparison of Comparative Example 3 (lacking the ternary compound antioxidant system) with Example 1: After 2000 hours of xenon lamp aging, the gloss retention rate of Comparative Example 3 was only 68%, a decrease of 22.7% compared to Example 1. The surface resistivity fluctuation rate was 22%, and the salt spray resistance time was shortened by 450 hours, with the coating showing obvious yellowing. This indicates that the hindered phenol 1076, DLTP, and T551 ternary compound system can synergistically inhibit oxidative aging and delay coating degradation. Single components or systems without antioxidants cannot achieve the same long-term stability.

[0057] (7) Comparison of Comparative Example 4 (non-segmented curing, same formulation as Example 1) with Example 1: The adhesion of Comparative Example 4 decreased to Grade 1, the impact strength was 75 kg·cm (a decrease of 11.8%), the salt spray resistance time was shortened by 250 h, and the gloss retention rate decreased by 13 percentage points. This proves that the segmented curing process (pre-curing + final curing) can gradually cross-link the coating, avoid the internal stress and porosity generated by one-time curing, and significantly improve the density and interfacial bonding of the coating. Non-segmented curing cannot achieve the same performance.

[0058] In summary, this invention achieves a balance of antistatic properties, mechanical properties, weather resistance, corrosion resistance, and environmental friendliness through the precise synergistic ratio of FEVE fluorocarbon resin, conductive carbon black-graphite composite powder, 593 epoxy curing agent, and a ternary compound antioxidant system, combined with interface control using titanate coupling agent and a segmented curing process. Examples 1-3 demonstrate that the verification scheme can be flexibly adjusted to adapt to different scenarios, while the comparative examples clearly identify the irreplaceable nature of each key element. The overall technical solution possesses industrial application value and advantages.

[0059] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and are not intended to limit the scope of protection of the present invention. Although the present invention has been described in detail with reference to preferred embodiments, those skilled in the art should understand that modifications or equivalent substitutions can be made to the technical solutions of the present invention without departing from the essence and scope of the technical solutions of the present invention.

Claims

1. A fluorocarbon powder coating, characterized in that, The raw materials include the following weight parts: 40-50 parts of FEVE fluorocarbon resin, 10-15 parts of conductive carbon black-graphite composite powder, 3.0-3.5 parts of 593 epoxy curing agent, 0.6-0.9 parts of epoxy silane KH-560, 0.6-1.0 parts of titanate coupling agent NDZ-101, 5-10 parts of rutile titanium dioxide, 3-8 parts of talc, 0.4-0.6 parts of 3-mercapto isooctyl propionate, and 0.08-0.12 parts of dibutyltin dilaurate.

2. A fluorocarbon powder paint according to claim 1, characterized in that: In the conductive carbon black-graphite composite powder, the graphite is flaky graphite, and the content is 85-95 wt%; the conductive carbon black is acetylene black, and the content is 5-15 wt%.

3. A fluorocarbon powder paint according to claim 1, characterized in that: It also includes 0.8-1.2 parts of a hindered phenol-thioester ternary compounded antioxidant system, which is compounded by hindered phenol 1076, thioester DLTP and metal deactivator T551 in a weight ratio of 3:2:

1.

4. A fluorocarbon powder paint according to claim 1, characterized in that: The 593 epoxy curing agent is an amino-terminated polyamide with an amine value of 600-700 mgKOH / g, a viscosity of 55-150 mPa・s at 25℃, and an effective solid content of ≥98 wt%.

5. A fluorocarbon powder paint according to claim 1, characterized in that: The epoxy silane KH-560 has an epoxy value of 0.45-0.55 eq / 100g and a hydrolysis degree of ≥95%.

6. A fluorocarbon powder paint according to claim 1, characterized in that: The FEVE fluorocarbon resin is a hydroxyl type FEVE fluorocarbon resin with a solid content of ≥60 wt%, a hydroxyl value of 50-80 mgKOH / g, and a viscosity of 2000-3000 mPa・s at 25℃.

7. A process for the production of a fluorocarbon powder coating as claimed in any one of claims 1 to 6, characterized in that The method includes the following steps: (1) Pretreatment of conductive filler: mix the conductive carbon black-graphite composite powder with the titanate coupling agent NDZ-101, add anhydrous ethanol as a dispersion medium, stir at a speed of 450-550 r / min for 15-25 min, stand for 8-12 min, and then dry to remove ethanol, to obtain a pretreated conductive filler; (2) Pretreatment of resin system: heat the FEVE fluorocarbon resin to 55-65℃, add the 593 epoxy curing agent, epoxy silane KH-560, and dibutyltin dilaurate in sequence, stir at a speed of 450-550 r / min for 15-25 min, and form a prepolymer resin system, which is cooled to below 45℃ for standby; (3) Mixing and granulation: weigh the pretreated conductive filler, prepolymer resin system, rutile titanium dioxide, talc, 3-mercapto isooctyl propionate, and hindered phenol-thioester ternary compounded antioxidant system according to the formula, mix uniformly, and then put into a twin-screw extruder, control the extrusion temperature to be 100-120℃, and obtain a coarse material through extrusion and crushing; (4) Preparation of finished product: sieve the coarse material to obtain a fluorocarbon powder coating with uniform particle size.

8. The method of claim 7, wherein: In step (1), the amount of anhydrous ethanol added is 30-50 wt% of the weight of the conductive carbon black-graphite composite powder; the drying temperature is 60-80℃, and the drying is performed until the ethanol is completely removed; in step (3), the screw rotation speed of the twin-screw extruder is 150-200 r / min; and in step (4), a 120-mesh sieve is used, and the obtained fluorocarbon powder coating is stable without layering or agglomeration.

9. The production method according to claim 8, characterized by, The fluorocarbon powder coating adopts a segmented curing process: pre-curing at 70-80℃ for 35-45min, and final curing at 100-120℃ for 35-45min.

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