Solvent resistant sand textured powder and method of making same

Abstract

The application discloses solvent-resistant sand-textured powder and a preparation method thereof, and relates to the technical field of powder coating preparation, which comprises the following steps: preparing raw materials, pretreating the raw materials, adding the pretreated raw materials into a high-speed mixer for premixing, adding the premixed materials into a double-screw extruder for melt extrusion to obtain melt strips, sending the melt strips into a cooling device for cooling and shaping to obtain granular intermediates, putting the granular intermediates into a pulverizer for pulverization, screening the pulverized materials to obtain powder-shaped solvent-resistant sand-textured powder, and performing quality detection on the powder-shaped solvent-resistant sand-textured powder. The application adopts the formula design of bisphenol A epoxy resin and high-Tg modified epoxy resin compounding+D50=10-micron high-purity quartz powder, combines process innovation of step-by-step mixing, double-screw partition precise temperature control, secondary drying and multi-stage screening, solves the problems of poor solvent resistance and uneven performance of traditional sand-textured powder, and realizes high-Tg coating film resistance to acetone and multi-scene adaptation.

Description

Technical Field

[0001] This invention relates to the field of powder coating preparation technology, specifically to a solvent-resistant textured powder and its preparation method. Background Technology

[0002] As a key functional component of powder coatings, textured powder is widely used in surface coating of household appliance casings, automotive parts, and hardware products due to its unique textured appearance and surface protection properties. In practical applications, these coated parts often come into contact with cleaning agents containing solvents such as acetone and alcohol. Therefore, solvent resistance becomes a core indicator of product quality. Industry standards typically require that the coating not show significant whitening or softening after 100 acetone wiping cycles. However, current textured powder products on the market exhibit a significant gap between performance and application requirements, with prominent technical bottlenecks, mainly reflected in the following aspects: On the one hand, existing resin systems struggle to balance textured finish and solvent resistance. While a single bisphenol A epoxy resin and dicyandiamide curing system is low-cost, its insufficient crosslinking density allows solvents to easily penetrate, causing severe whitening of the coating after acetone wiping and leading to swelling and softening after prolonged use. A bisphenol A epoxy resin and polyester resin blend can improve texture uniformity, but the ester bonds in the polyester molecular chain are sensitive to ketone solvents, further reducing the coating's solvent resistance; after 100 wiping cycles, the softening rate exceeds 80%. The polyurethane resin and TDI curing system exhibits even worse acetone resistance due to the high sensitivity of urethane bonds to solvents, showing significant whitening and cracking after only 50 wiping cycles. While the polyester resin and TGIC curing system can increase crosslinking density, it fails to address the inherent solvent resistance of polyester, thus still not meeting the demands of high-end coatings.

[0003] On the other hand, there are significant deficiencies in filler selection and preparation processes. Existing products mostly use conventional fillers such as barium sulfate, mica powder, and calcium carbonate. These fillers either have strong surface hydrophilicity and poor resin compatibility, forming micropores within the coating film and accelerating solvent penetration; or they have weak solvent resistance, leading to structural damage after prolonged solvent contact and a decline in the mechanical properties of the coating film. Meanwhile, while the use of texture agents and wax additives can improve surface texture and abrasion resistance, it reduces the surface energy of the coating, increases the risk of interlayer separation, and affects overall protective performance. In terms of the preparation process, insufficient raw material pretreatment, inadequate mixing uniformity, and improper extrusion temperature control result in poor batch stability, further exacerbating fluctuations in solvent resistance.

[0004] Furthermore, some manufacturers use materials such as untested samples, stock powder, and recycled powder to reduce costs. The quality differences in these materials not only affect the uniformity of the textured effect but also introduce impurities, leading to a decrease in coating density and making it easier for solvents to penetrate the coating. These problems collectively make it difficult for existing textured powder products to meet the stringent solvent resistance requirements of high-end industries such as home appliances and automobiles. Therefore, developing a textured powder and its preparation method that combines excellent solvent resistance, stable mechanical properties, and a good textured feel has become an urgent need in the industry. Summary of the Invention

[0005] To solve the above-mentioned technical problems, a solvent-resistant textured powder and its preparation method are provided. This technical solution solves the above-mentioned problems.

[0006] To achieve the above objectives, the technical solution adopted by the present invention is as follows: A solvent-resistant textured powder comprises: 30-50 parts of bisphenol A epoxy resin, 10-20 parts of modified high Tg epoxy resin, 4-6 parts of dicyandiamide curing agent, 15-25 parts of quartz powder, and 2-5 parts of textured agent.

[0007] Preferably, the bisphenol A epoxy resin is Huangshan Hengyuan HY903H epoxy resin with an epoxy equivalent of 750-850 g / eq, the modified coating high Tg epoxy resin is Huangshan Hengyuan HYT6508 epoxy resin with an epoxy equivalent of 380-420 g / eq, the quartz powder has a particle size D50 of 10 micrometers, the texture agent is one of polytetrafluoroethylene micro powder and acrylate micro powder with a particle size of 5-15 micrometers, and the solvent-resistant texture powder, after curing, basically turns white after 100 wipings with acetone, and the coating does not soften.

[0008] Preferably, the glass transition temperature (Tg) of the cured solvent-resistant textured powder is ≥80℃, the adhesion grade is ≥5B (cross-cut test), and the impact resistance is ≥50cm (drop ball impact test); the purity of the quartz powder is ≥98% to avoid impurities affecting the solvent resistance of the coating.

[0009] A method for preparing solvent-resistant textured powder, comprising the following steps: Prepare the raw materials, including 30-50 parts of bisphenol A epoxy resin, 10-20 parts of modified high Tg epoxy resin for coating, 4-6 parts of dicyandiamide curing agent, 15-25 parts of quartz powder and 2-5 parts of texture agent. Pre-treat the raw materials to remove impurities and dry them. The pretreated raw materials are added to a high-speed mixer for premixing, and the mixing parameters are controlled to obtain a uniform premix. The premixed material is added to a twin-screw extruder for melt extrusion. The temperature of each section of the extruder and the screw speed are set to obtain molten material strips. The molten strip is fed into a cooling device to cool and shape it. After cooling, it is granulated to obtain granular intermediates. The granular intermediate is pulverized in a pulverizer and then sieved to obtain a powdered solvent-resistant textured powder. The powdered solvent-resistant textured powder is subjected to quality testing, and qualified products are packaged and stored.

[0010] Preferably, the raw materials include 30-50 parts of bisphenol A epoxy resin, 10-20 parts of modified high-Tg epoxy resin for coating, 4-6 parts of dicyandiamide curing agent, 15-25 parts of quartz powder, and 2-5 parts of texture agent. Pretreatment of the raw materials to remove impurities and drying specifically includes: The bisphenol A epoxy resin and the modified high Tg epoxy resin for coating were dried at a temperature of 80-100℃ for 2-3 hours to remove moisture from the raw materials. Quartz powder is treated to remove impurities by screening it through a 100-mesh sieve to remove large particles. Weigh each raw material according to the proportions and store them separately in clean, dry containers for later use. The dicyandiamide curing agent must be weighed in a dry environment to avoid moisture absorption that could affect the curing effect.

[0011] Preferably, the step of adding the pretreated raw materials to a high-speed mixer for premixing, controlling the mixing parameters, and obtaining a uniform premix specifically includes: First, add bisphenol A epoxy resin, modified high Tg epoxy resin for coating and dicyandiamide curing agent to a high-speed mixer, set the speed to 1000-1200 r / min, and mix for 3-5 minutes; Add quartz powder and sanding agent, adjust the speed to 1300-1500 r / min, and continue mixing for 2-3 minutes; During the mixing process, the temperature inside the mixer should be controlled to ≤40℃ to prevent the raw materials from softening and clumping in advance. After mixing, the uniformity of the premix should be checked to ensure that there is no obvious particle agglomeration.

[0012] Preferably, the step of adding the premix to a twin-screw extruder for melt extrusion, setting the temperature of each section of the extruder and the screw speed to obtain the molten material strip specifically includes: The temperature settings for each section of the twin-screw extruder are as follows: Zone 1 105~110℃, Zone 2 115~120℃, Zone 3 125~130℃, Zone 4 135~140℃, and Die head 130~135℃. The screw speed is set to 30-50 r / min to ensure that the raw material is fully melted and does not undergo thermal degradation. During the extrusion process, the condition of the material strip is monitored in real time. If the surface of the material strip is rough or there are bubbles, the extrusion temperature is adjusted by ±5℃ and the screw speed by ±5r / min. The molten material strip is extruded through the die of the extruder head, with a die diameter of 2-3mm.

[0013] Preferably, the step of feeding the molten strip into a cooling device for cooling and shaping, and then pelletizing it to obtain a granular intermediate specifically includes: The cooling device uses a water cooling tank, and the temperature of the water cooling tank is controlled at 20-30℃. The material strip is cooled in the water cooling tank for 1-2 minutes to ensure that the material strip is completely solidified and shaped. The cooled material strips are fed into a pelletizer for pelleting, with a pellet length of 2-5 mm and a particle size deviation of ≤0.5 mm. The pelletized intermediate is then sent to a dryer for secondary drying at a temperature of 60–80°C for 1–1.5 hours to remove the moisture adsorbed during the cooling process.

[0014] Preferably, the step of pulverizing the granular intermediate in a pulverizer and then sieving it to obtain powdered solvent-resistant textured powder specifically includes: The pulverizer is a universal pulverizer with a pulverizing speed of 2000-3000 r / min and a pulverizing time of 3-5 minutes; The pulverized powder is sieved using a vibrating screen with a mesh size of 120-180 to ensure uniform particle size of the sand texture powder and avoid coarse particles affecting the coating effect. The coarse powder after screening is returned to the pulverizer for re-grinding, while the fine powder is collected as the product to be tested. The screening process is carried out in a closed environment to prevent dust pollution.

[0015] Preferably, the quality inspection of the powdered solvent-resistant textured powder, and the packaging and storage of qualified products specifically include: Quality testing items include: particle size distribution (tested by laser particle size analyzer, D50 deviation ≤ 1 micrometer), acetone resistance (100 back and forth wiping cycles, observing the degree of whitening and coating hardness), and melt flowability (tested by melt flow rate meter, ≥ 10 g / 10 min at 150℃ / 5 kg). Qualified products are vacuum-packed in aluminum-plastic composite bags, with each bag weighing 25kg or 50kg. After packaging, the products are stored in a cool, dry warehouse with the temperature controlled between 15 and 25°C and the relative humidity ≤60%. The shelf life is 12 months, and the products are sampled once a month to ensure stable performance.

[0016] Compared with the prior art, the beneficial effects of the present invention are as follows: This invention employs a formulation combining bisphenol A epoxy resin (HY903H) and high-Tg modified epoxy resin (HYT6508), along with high-purity quartz powder with a D50 of 10 microns. Through synergistic crosslinking of the resins, the crosslinking density of the coating is increased, while the quartz powder constructs a solvent-resistant physical barrier. This fundamentally solves the problems of severe whitening and softening of traditional textured coatings when wiped with acetone. After curing, the coating exhibits a Tg ≥ 82℃, adhesion ≥ 4B, and impact resistance ≥ 50cm. The innovative process involves step-by-step mixing (resin and curing agent mixed first, followed by the addition of filler and textured agent) and precise zoning via twin-screw extrusion. Temperature control (105~140℃), secondary drying, and multi-stage sieving (120~200 mesh) ensure uniform powder particle size (D50 deviation ≤1.2 microns) and batch performance variation ≤3%, avoiding the defects of uneven mixing and disordered particle size in traditional processes. The product performance is comprehensively optimized, with no clumping after 12 months of storage. Its solvent resistance, mechanical properties, and stability far exceed those of traditional products. Moreover, it can be flexibly adapted to different high-end coating scenarios such as home appliance shells and automotive parts by adjusting the modified resin ratio and the type of texture agent, solving the pain points of traditional texture powder having a narrow range of applications and being unable to meet stringent requirements. Attached Figure Description

[0017] Figure 1 This is a flowchart of the preparation steps of the present invention. Detailed Implementation

[0018] The following description is intended to disclose the invention and enable those skilled in the art to implement it. The preferred embodiments described below are merely examples, and other obvious variations will occur to those skilled in the art.

[0019] A solvent-resistant textured powder comprises: 30-50 parts of bisphenol A epoxy resin, 10-20 parts of modified high Tg epoxy resin, 4-6 parts of dicyandiamide curing agent, 15-25 parts of quartz powder, and 2-5 parts of textured agent.

[0020] The bisphenol A epoxy resin is Huangshan Hengyuan HY903H epoxy, with an epoxy equivalent of 750-850 g / eq. The modified high Tg epoxy resin for the coating is Huangshan Hengyuan HYT6508 epoxy, with an epoxy equivalent of 380-420 g / eq. The particle size D50 of the quartz powder is 10 micrometers. The texture agent is one of polytetrafluoroethylene micro powder and acrylate micro powder, with a particle size of 5-15 micrometers. After curing, the solvent-resistant texture powder basically turns white after 100 wipings with acetone, and the coating does not soften.

[0021] The solvent-resistant textured powder, after curing, has a glass transition temperature (Tg) ≥ 80℃, an adhesion grade ≥ 5B (cross-cut test), and an impact resistance ≥ 50cm (drop ball impact test); the quartz powder has a purity ≥ 98% to avoid impurities affecting the solvent resistance of the coating.

[0022] A method for preparing solvent-resistant textured powder, comprising the following steps: S1. Prepare raw materials, including 30-50 parts of bisphenol A epoxy resin, 10-20 parts of modified high Tg epoxy resin for coating, 4-6 parts of dicyandiamide curing agent, 15-25 parts of quartz powder and 2-5 parts of texture agent. Pre-treat the raw materials to remove impurities and dry them. S2. Add the pretreated raw materials to a high-speed mixer for premixing, control the mixing parameters, and obtain a uniform premix. S3. Add the premixed material to a twin-screw extruder for melt extrusion, set the temperature of each section of the extruder and the screw speed to obtain molten material strips; S4. The molten strip is fed into a cooling device to cool and shape it. After cooling, it is granulated to obtain granular intermediate. S5. Place the granular intermediate into a pulverizer and pulverize it. After pulverization, sieve it to obtain powdered solvent-resistant textured powder. S6. Conduct quality inspection on the powdered solvent-resistant textured powder, and package and store qualified products.

[0023] S1 specifically includes: The bisphenol A epoxy resin and the modified high Tg epoxy resin for coating were dried at a temperature of 80-100℃ for 2-3 hours to remove moisture from the raw materials. Quartz powder is treated to remove impurities by screening it through a 100-mesh sieve to remove large particles. Weigh each raw material according to the proportions and store them separately in clean, dry containers for later use. The dicyandiamide curing agent must be weighed in a dry environment to avoid moisture absorption that could affect the curing effect.

[0024] S2 specifically includes: First, add bisphenol A epoxy resin, modified high Tg epoxy resin for coating and dicyandiamide curing agent to a high-speed mixer, set the speed to 1000-1200 r / min, and mix for 3-5 minutes; Add quartz powder and sanding agent, adjust the speed to 1300-1500 r / min, and continue mixing for 2-3 minutes; During the mixing process, the temperature inside the mixer should be controlled to ≤40℃ to prevent the raw materials from softening and clumping in advance. After mixing, the uniformity of the premix should be checked to ensure that there is no obvious particle agglomeration.

[0025] S3 specifically includes: The temperature settings for each section of the twin-screw extruder are as follows: Zone 1 105~110℃, Zone 2 115~120℃, Zone 3 125~130℃, Zone 4 135~140℃, and Die head 130~135℃. The screw speed is set to 30-50 r / min to ensure that the raw material is fully melted and does not undergo thermal degradation. During the extrusion process, the condition of the material strip is monitored in real time. If the surface of the material strip is rough or there are bubbles, the extrusion temperature is adjusted by ±5℃ and the screw speed by ±5r / min. The molten material strip is extruded through the die of the extruder head, with a die diameter of 2-3mm.

[0026] S4 specifically includes: The cooling device uses a water cooling tank, and the temperature of the water cooling tank is controlled at 20-30℃. The material strip is cooled in the water cooling tank for 1-2 minutes to ensure that the material strip is completely solidified and shaped. The cooled material strips are fed into a pelletizer for pelleting, with a pellet length of 2-5 mm and a particle size deviation of ≤0.5 mm. The pelletized intermediate is then sent to a dryer for secondary drying at a temperature of 60–80°C for 1–1.5 hours to remove the moisture adsorbed during the cooling process.

[0027] S5 specifically includes: The pulverizer is a universal pulverizer with a pulverizing speed of 2000-3000 r / min and a pulverizing time of 3-5 minutes; The pulverized powder is sieved using a vibrating screen with a mesh size of 120-180 to ensure uniform particle size of the sand texture powder and avoid coarse particles affecting the coating effect. The coarse powder after screening is returned to the pulverizer for re-grinding, while the fine powder is collected as the product to be tested. The screening process is carried out in a closed environment to prevent dust pollution.

[0028] S6 specifically includes: Quality testing items include: particle size distribution (tested by laser particle size analyzer, D50 deviation ≤ 1 micrometer), acetone resistance (100 back and forth wiping cycles, observing the degree of whitening and coating hardness), and melt flowability (tested by melt flow rate meter, ≥ 10 g / 10 min at 150℃ / 5 kg). Qualified products are vacuum-packed in aluminum-plastic composite bags, with each bag weighing 25kg or 50kg. After packaging, the products are stored in a cool, dry warehouse with the temperature controlled between 15 and 25°C and the relative humidity ≤60%. The shelf life is 12 months, and the products are sampled once a month to ensure stable performance.

[0029] Experimental Data 1: Comparison of Acetone Wiping Resistance of Different Resin Systems: Experimental conditions: withstands 50 acetone wiping cycles, ambient temperature (23±2)℃, humidity (50±5)%RH, test standard ISO16750-5:2023; Experimental formula and results:

[0030] The sample was wiped with acetone 50 times. A slight discoloration was visible, but there was no obvious whitening or softening of the coating. The test result was compliant, meeting the company's internal quality control and product development requirements. Experimental Data 2: Comparison of Solvent Resistance of Different Fillers Basic formula: 60 parts bisphenol A epoxy resin (HY903H) + 3.15 parts dicyandiamide curing agent + 0.2 parts PTFE texture agent + 0.2 parts bentonite + 0.3 parts PE wax powder + 1.0 part carbon black, the filler is powder with D50=10 microns, the addition amount is 35.15 parts;

[0031] Conclusion: When quartz powder is used as a filler, the coating film exhibits the best solvent resistance, with only slight whitening and minimal softening, making it the optimal filler choice.

[0032] Experimental Data 3: Optimization Experiment of Compound Resin Experimental formula:

[0033] Conclusion: The combination of bisphenol A epoxy resin and modified high Tg epoxy resin significantly improves acetone resistance, and the coating does not turn white after wiping, remains hard and does not soften, showing better performance than a single resin system.

[0034] Example 1

[0035] A method for preparing solvent-resistant textured powder, comprising the following steps: S1: Prepare the following materials in the following proportions: 40 parts of bisphenol A epoxy resin (Huangshan Hengyuan HY903H), 15 parts of modified high Tg epoxy resin for coating (Huangshan Hengyuan HYT6508), 5 parts of dicyandiamide curing agent, 20 parts of quartz powder (purity 98%, D50=10 microns), and 3 parts of polytetrafluoroethylene texture agent (particle size 8 microns). S2: BPA epoxy resin and modified high Tg epoxy resin are dried at 90℃ for 2.5 hours, and quartz powder is passed through a 100-mesh sieve to remove impurities; dicyandiamide curing agent is weighed under dry conditions, and each raw material is stored in a clean and dry container. S3: First, add epoxy resin and curing agent to a high-speed mixer and mix at 1100r / min for 4 minutes. Then add quartz powder and texture agent, adjust the speed to 1400r / min and continue mixing for 2.5 minutes, controlling the mixing temperature to ≤40℃. S4: Add the premixed material to the twin-screw extruder, set the temperature of each zone: Zone 1 108℃, Zone 2 118℃, Zone 3 128℃, Zone 4 138℃, Die head 132℃, screw speed 40r / min, die diameter 2.5mm, and extrude molten material strips. S5: The material strip is fed into a 25℃ water cooling tank for 1.5 minutes to cool, and the pellet length is 3mm. The pellets are then dried again at 70℃ for 1.2 hours. S6: The particles are put into a universal pulverizer and pulverized at 2500r / min for 4 minutes. The pulverized powder is then collected by sieving through a 150-mesh vibrating screen. S7: Powder D50 = 10 ± 1 micrometer, melt flowability (150℃ / 5kg) 12g / 10min, and basically turns white after 100 acetone wiping cycles; S8: Qualified powder is vacuum-packed in aluminum-plastic composite bags and stored in a warehouse at 20℃ and 55% relative humidity, with monthly random checks.

[0036] Example 2

[0037] A method for preparing solvent-resistant textured powder, comprising the following steps: S1: Prepare the following materials in the following proportions: 35 parts of bisphenol A epoxy resin (Huangshan Hengyuan HY903H), 20 parts of modified high Tg epoxy resin for coating (Huangshan Hengyuan HYT6508), 6 parts of dicyandiamide curing agent, 22 parts of quartz powder (purity 99%, D50=10 microns), and 4 parts of acrylic ester texture agent (particle size 12 microns). S2: The epoxy resin is dried at 100℃ for 2 hours, and the quartz powder is sieved through a 100-mesh screen to remove impurities; the curing agent is weighed under the drying environment, and the raw materials are stored separately. S3: First, mix the resin and curing agent at 1200r / min for 5 minutes, then add the filler and texture agent, mix at 1500r / min for 3 minutes, and control the mixing temperature to ≤38℃; S4: Twin-screw extruder parameters: Zone 1 110℃, Zone 2 120℃, Zone 3 130℃, Zone 4 140℃, Die head 135℃, Screw speed 45r / min, Die diameter 3mm; S5: Cool in a 30℃ water-cooling bath for 2 minutes, cut into pellets of 4mm length, and dry at 60℃ for 1.5 hours; S6: The pulverizer pulverizes at 3000r / min for 3 minutes, then sieves through a 200-mesh screen; S7: The powder D50 was 10±0.8 micrometers, the melt flowability was 14g / 10min, and there was no obvious whitening after wiping with acetone; S8: After vacuum packaging, store in a warehouse at 18℃ and 50% relative humidity, and monitor storage stability.

[0038] Example 3

[0039] A method for preparing solvent-resistant textured powder, comprising the following steps: S1: Prepare the following materials in the following proportions: 50 parts of bisphenol A epoxy resin (Huangshan Hengyuan HY903H), 10 parts of modified high Tg epoxy resin for coating (Huangshan Hengyuan HYT6508), 4 parts of dicyandiamide curing agent, 25 parts of quartz powder (purity 98%, D50=10 microns), and 2 parts of polytetrafluoroethylene texture agent (particle size 5 microns). S2: Epoxy resin is dried at 80℃ for 3 hours, and quartz powder is passed through a 100-mesh sieve; drying environment treatment curing agent; S3: Mix the resin and curing agent at 1000r / min for 3 minutes, then add other components and mix at 1300r / min for 2 minutes, controlling the temperature to ≤40℃; S4: Extruder temperature: Zone 1 105℃, Zone 2 115℃, Zone 3 125℃, Zone 4 135℃, Die head 130℃, Screw speed 35r / min, Die diameter 2mm; S5: Cool in a 20℃ water-cooling bath for 1 minute, cut into pellets of 2mm length, and dry at 80℃ for 1 hour; S6: Grind at 2000r / min for 5 minutes, then sieve through a 120-mesh screen; S7: The powder D50 is 10±1.2 micrometers, the melt flowability is 11g / 10min, and the acetone resistance meets the standard. S8: After vacuum packaging, store in a warehouse at 25℃ and 60% relative humidity, and record changes in powder flowability.

[0040] Comparative Example Traditional sand texture powder preparation method: only 60 parts of bisphenol A epoxy resin (HY903H), 5 parts of dicyandiamide curing agent, 25 parts of barium sulfate, and 3 parts of ordinary sand texture agent are used as raw materials; the resin is not dried during preparation, and all raw materials are added to the mixer at 800 r / min for 5 minutes; the twin-screw extrusion temperature is uniformly set to 120℃ and the screw speed is 60 r / min; after cooling, it is directly pulverized without secondary drying and precise sieving (only passing through an 80 mesh sieve).

[0041] The product has the following defects: severe whitening after 100 acetone wiping cycles (whitening area > 60%), and the coating film is noticeably soft; uneven particle size distribution (D50 fluctuation range 8-15 microns); clumping occurs after 3 months of storage; the coating film Tg value is only 65℃, the adhesion grade is 3B, and the impact resistance is 30cm, which cannot meet the needs of high-end coating.

[0042] The table below shows the properties of the textured powder prepared in different embodiments.

[0043] In summary, the advantages of this invention are: Compared to the simple combination of a single resin and inferior filler in the comparative example, this invention adopts a synergistic design of "dual resin compounding + functional filler". Through the precise ratio of bisphenol A epoxy resin (750-850 g / eq) and high Tg modified epoxy resin (380-420 g / eq) (as in Example 2, 35:20), the crosslinking density of the coating film is increased by more than 30%, and the Tg value exceeds 80℃, fundamentally solving the problem of insufficient solvent resistance of traditional products. The combination of quartz powder (D50=10 micrometers) and polytetrafluoroethylene / acrylate texture agent not only utilizes the solvent resistance of quartz powder to build a physical barrier, but also optimizes the surface texture through the micro-nano structure of the texture agent, achieving a dual improvement in "protective performance + appearance effect". The advanced and controllable manufacturing process significantly improves product quality stability: A stepwise mixing strategy (resin and curing agent mixed first, then filler added) combined with gradient speeds (1000-1500 r / min) solves the performance fluctuation problem caused by uneven mixing in the comparative example; precise temperature control (±1℃) in each zone of the twin-screw extruder avoids resin degradation or incomplete melting defects; secondary drying and multi-stage sieving (120-200 mesh) ensure powder particle size deviation ≤1 micrometer, far superior to the random distribution of 8-15 micrometers in the comparative example. These process innovations keep batch-to-batch performance differences within 3%, meeting the requirements of industrial mass production. The product's performance has been comprehensively optimized, making it suitable for a wider range of applications: In terms of mechanical properties, the example product has an adhesion rating of ≥4B and an impact resistance of ≥50cm, solving the problems of easy peeling and weak impact resistance of traditional coatings; in terms of storage stability, through raw material drying (moisture content ≤0.1%) and vacuum packaging technology, the product's shelf life has been extended to 12 months, overcoming the defect of clumping after 3 months in the comparative example. By adjusting the modified resin ratio (10-20 parts) and the type of texture agent, it can be precisely matched to different scenarios such as home appliance shells (high solvent resistance requirements) and automotive parts (high mechanical performance requirements), while traditional products can only be used for low-requirement ordinary hardware coatings; The process parameters are flexible and adjustable, and it has the ability to be customized. For the needs of high-end home appliances, the proportion of modified Tg resin can be increased (e.g., 20 parts in Example 2) and high-speed mixing at 1500r / min can be used to enhance solvent resistance. For the needs of thick coating, the extrusion temperature can be reduced (e.g., 105-135℃ in Example 3) to improve melt flow. For appearance requirements, the fineness of the texture can be adjusted by switching the type of texture agent (PTFE / acrylate). This closed-loop control system of "formulation-process-performance" solves the technical bottleneck of traditional products with fixed processes that cannot adapt to diversified needs.

[0044] The foregoing has shown and described the basic principles, main features, and advantages of the present invention. Those skilled in the art should understand that the present invention is not limited to the above embodiments. The embodiments and descriptions in the specification are merely principles of the invention. Various changes and modifications can be made to the invention without departing from its spirit and scope, and all such changes and modifications fall within the scope of the claimed invention. The scope of protection claimed by the appended claims and their equivalents is defined.

Claims

1. A solvent-resistant textured powder, characterized in that, include: The mixture consists of 30-50 parts of bisphenol A epoxy resin, 10-20 parts of modified high-Tg epoxy resin for coating, 4-6 parts of dicyandiamide curing agent, 15-25 parts of quartz powder, and 2-5 parts of texture agent.

2. The solvent-resistant textured powder according to claim 1, characterized in that: The bisphenol A epoxy resin is Huangshan Hengyuan HY903H epoxy, with an epoxy equivalent of 750-850 g / eq. The modified high Tg epoxy resin for the coating is Huangshan Hengyuan HYT6508 epoxy, with an epoxy equivalent of 380-420 g / eq. The particle size D50 of the quartz powder is 10 micrometers. The texture agent is one of polytetrafluoroethylene micro powder and acrylate micro powder, with a particle size of 5-15 micrometers. After curing, the solvent-resistant texture powder basically turns white after 100 wipings with acetone, and the coating does not soften.

3. The solvent-resistant textured powder according to claim 2, characterized in that, The solvent-resistant textured powder, after curing, produces a coating with a glass transition temperature ≥80℃, an adhesion grade ≥5B, and an impact resistance ≥50cm. The quartz powder has a purity ≥98% to prevent impurities from affecting the solvent resistance of the coating.

4. A method for preparing solvent-resistant textured powder, characterized in that, The preparation steps are as follows: S1. Prepare raw materials, including 30-50 parts of bisphenol A epoxy resin, 10-20 parts of modified high Tg epoxy resin for coating, 4-6 parts of dicyandiamide curing agent, 15-25 parts of quartz powder and 2-5 parts of texture agent. Pre-treat the raw materials to remove impurities and dry them. S2. Add the pretreated raw materials to a high-speed mixer for premixing, control the mixing parameters, and obtain a uniform premix. S3. Add the premixed material to a twin-screw extruder for melt extrusion, set the temperature of each section of the extruder and the screw speed to obtain molten material strips; S4. The molten strip is fed into a cooling device to cool and shape it. After cooling, it is granulated to obtain granular intermediate. S5. Place the granular intermediate into a pulverizer and pulverize it. After pulverization, sieve it to obtain powdered solvent-resistant textured powder. S6. Conduct quality inspection on the powdered solvent-resistant textured powder, and package and store qualified products.

5. The method for preparing a solvent-resistant textured powder according to claim 4, characterized in that, S1 specifically includes: The bisphenol A epoxy resin and the modified high Tg epoxy resin for coating were dried at a temperature of 80-100℃ for 2-3 hours to remove moisture from the raw materials. Quartz powder is treated to remove impurities by screening it through a 100-mesh sieve to remove large particles. Weigh each raw material according to the proportions and store them separately in clean, dry containers for later use. The dicyandiamide curing agent must be weighed in a dry environment to avoid moisture absorption that could affect the curing effect.

6. The method for preparing a solvent-resistant textured powder according to claim 4, characterized in that, S2 specifically includes: First, add bisphenol A epoxy resin, modified high Tg epoxy resin for coating and dicyandiamide curing agent to a high-speed mixer, set the speed to 1000-1200 r / min, and mix for 3-5 minutes; Add quartz powder and sanding agent, adjust the speed to 1300-1500 r / min, and continue mixing for 2-3 minutes; During the mixing process, the temperature inside the mixer should be controlled to ≤40℃ to prevent the raw materials from softening and clumping in advance. After mixing, the uniformity of the premix should be checked to ensure that there is no obvious particle agglomeration.

7. The method for preparing a solvent-resistant textured powder according to claim 4, characterized in that, S3 specifically includes: The temperature settings for each section of the twin-screw extruder are as follows: Zone 1 105~110℃, Zone 2 115~120℃, Zone 3 125~130℃, Zone 4 135~140℃, and Die head 130~135℃. The screw speed is set to 30-50 r / min to ensure that the raw material is fully melted and does not undergo thermal degradation. During the extrusion process, the condition of the material strip is monitored in real time. If the surface of the material strip is rough or there are bubbles, the extrusion temperature is adjusted by ±5℃ and the screw speed by ±5r / min. The molten material strip is extruded through the die of the extruder head, with a die diameter of 2-3mm.

8. The method for preparing a solvent-resistant textured powder according to claim 4, characterized in that, S4 specifically includes: The cooling device uses a water cooling tank, and the temperature of the water cooling tank is controlled at 20-30℃. The material strip is cooled in the water cooling tank for 1-2 minutes to ensure that the material strip is completely solidified and shaped. The cooled material strips are fed into a pelletizer for pelleting, with a pellet length of 2-5 mm and a particle size deviation of ≤0.5 mm. The pelletized intermediate is then sent to a dryer for secondary drying at a temperature of 60–80°C for 1–1.5 hours to remove the moisture adsorbed during the cooling process.

9. The method for preparing a solvent-resistant textured powder according to claim 5, characterized in that, S5 specifically includes: The pulverizer is a universal pulverizer with a pulverizing speed of 2000-3000 r / min and a pulverizing time of 3-5 minutes; The pulverized powder is sieved using a vibrating screen with a mesh size of 120-180 to ensure uniform particle size of the sand texture powder and avoid coarse particles affecting the coating effect. The coarse powder after screening is returned to the pulverizer for re-grinding, while the fine powder is collected as the product to be tested. The screening process is carried out in a closed environment to prevent dust pollution.

10. The method for preparing a solvent-resistant textured powder according to claim 4, characterized in that, S6 specifically includes: Quality testing items include: particle size distribution, acetone resistance, and melt flowability; Qualified products are vacuum-packed in aluminum-plastic composite bags, with each bag weighing either 25kg or 50kg. After packaging, the products are stored in a cool, dry warehouse with the temperature controlled between 15 and 25°C and the relative humidity ≤60%. The shelf life is 12 months, and the products are sampled once a month to ensure stable performance.

Images