Surface anti-bonding coating material of wringing roller and preparation method of surface anti-bonding coating material

Abstract

The invention relates to the technical field of functional coatings, and particularly discloses a surface anti-bonding coating material of a wringing roller and a preparation method of the surface anti-bonding coating material. The composition comprises the following components in parts by weight: 30-50 parts of matrix resin, 10-20 parts of modified polytetrafluoroethylene, 5-15 parts of a filler, 2-8 parts of an auxiliary agent, 20-40 parts of a solvent, 2-4 parts of a heat stabilizer and 3-6 parts of a nano reinforcing agent, the preparation method comprises the steps of matrix surface sand blasting treatment and solvent cleaning, nano reinforcing agent pre-dispersion, graded mixing, sequential adding and intermittent ultrasonic treatment, vacuum defoaming, high-pressure airless spraying coating, stepped procedure curing and step-by-step polishing aftertreatment. According to the composition disclosed by the invention, through a specific component ratio and a surface modification technology, a coating has excellent anti-bonding performance and mechanical durability; besides, according to the preparation method disclosed by the invention, by optimizing process parameters and controlling the process, the uniformity and compactness of the coating structure are ensured, and the stability and reliability of the product quality are improved.

Description

Technical Field

[0001] This application relates to the field of functional coating technology, and more specifically, it relates to an anti-adhesion coating material for the surface of a squeeze roller and a method for preparing the same. Background Technology

[0002] Squeeze rolls are key equipment components in industries such as papermaking, printing and dyeing, and metallurgy. Their core function is to dehydrate, remove impurities, or level materials through extrusion. Their surface properties directly determine production efficiency, material processing quality, and equipment lifespan. In actual operation, the surface of the squeeze roll is in continuous contact with moist materials, fibers, or sticky media, making it highly susceptible to adhesion. This leads to material residue buildup, unstable processing results, and accelerated roll wear, increasing equipment maintenance frequency and costs. Therefore, providing the squeeze roll surface with excellent anti-adhesion properties is a core requirement for ensuring its stable operation.

[0003] While various anti-adhesion coating materials have emerged in the existing technology, they all share a common core technical problem: it is difficult to simultaneously achieve excellent anti-adhesion properties and reliable mechanical durability. Some coatings achieve a certain anti-adhesion effect by adding fluorine-based materials, but due to unreasonable component matching and insufficient structural density, their wear resistance and bonding strength with the substrate are poor. Under complex working conditions of long-term friction, pressure, and temperature fluctuations, they are prone to failure such as peeling and excessive wear. On the other hand, coatings that focus on improving mechanical strength often fail to meet practical application requirements due to improper surface energy design or insufficient component synergy.

[0004] This technical defect makes it difficult for existing coatings to adapt to the harsh working environment of squeeze rollers, resulting in frequent coating failures in practical applications: on the one hand, insufficient anti-adhesion performance leads to material adhesion and accumulation, affecting production continuity and material handling quality; on the other hand, lack of mechanical durability causes rapid wear and peeling of the coating, which not only requires frequent shutdowns for maintenance and increases overall operating costs, but may also contaminate materials due to coating peeling, further affecting product quality. Summary of the Invention

[0005] To address the problem that existing anti-adhesion coatings for squeeze rollers cannot simultaneously achieve both anti-adhesion properties and mechanical durability, this application provides an anti-adhesion coating material for the surface of a squeeze roller and its preparation method.

[0006] In a first aspect, this application provides a surface anti-sticking coating material for a squeeze roller, employing the following technical solution: A surface anti-adhesion coating material for a squeeze roller, the coating material being composed of the following components by weight: 30-50 parts of base resin, 10-20 parts of modified polytetrafluoroethylene, 5-15 parts of filler, 2-8 parts of additives, 20-40 parts of solvent, 2-4 parts of heat stabilizer, and 3-6 parts of nano-reinforcing agent.

[0007] By employing the above technical solutions, the base resin constructs the basic framework of the coating, supporting the various functional components and providing a structural foundation for the overall performance of the coating. Modified polytetrafluoroethylene reduces the surface energy of the coating, decreasing the adsorption of viscous media and thus imparting anti-adhesion properties. Fillers fill the internal voids of the coating, optimizing its microstructure and improving its density. Additives improve the dispersion uniformity of the components and the leveling process during coating, promoting synergistic dispersion and smooth surface formation, ensuring the stability and regularity of the coating preparation process. Solvents dissolve the base resin and disperse other solid components, adjusting the coating viscosity to suit the coating process, creating conditions for uniform mixing and subsequent coating operations. Heat stabilizers inhibit thermal oxidative degradation during curing and use, protecting the integrity of the coating's internal structure and maintaining long-term performance stability. Nano-reinforcing agents synergistically interact with the base resin and fillers, strengthening the mechanical support of the coating and improving its overall mechanical properties. Through the synergistic effects of these components in specific proportions, a structurally stable composite coating system is constructed.

[0008] Preferably, the matrix resin is epoxy resin or polyurethane resin; the filler is nano-silica or nano-alumina; the additives include dispersant and leveling agent, the dispersant is sodium polycarboxylate, the leveling agent is hydrogenated castor oil, and the weight ratio of sodium polycarboxylate to hydrogenated castor oil is 1.5:1 to 2.5:1.

[0009] By adopting the above technical solutions, epoxy resin or polyurethane resin is selected as the matrix resin. Its excellent adhesion and structural stability serve to firmly support the various functional components, thus providing a fundamental guarantee for the bonding between the coating and the extrusion roller substrate and the overall structural strength of the coating. Nano-silica or nano-alumina is used as filler, utilizing its nanoscale micro-size characteristics to fill the tiny voids inside the coating and refine its microstructure, thereby enhancing the coating's structural density. The additives are clearly defined as sodium polycarboxylate dispersant and hydrogenated castor oil leveling agent, with a weight ratio of 1.5:1 to 2.5:1. This allows sodium polycarboxylate to fully disperse the solid components and inhibit agglomeration, while hydrogenated castor oil effectively regulates the leveling state during coating application. Together, they optimize the uniformity of component dispersion and the coating's forming effect, ensuring a smooth and regular coating surface and that all internal components function synergistically.

[0010] Preferably, the solvent is composed of acetone and xylene, with a mass ratio of 60-70% acetone and 30-40% xylene; the heat stabilizer is dibutyltin dilaurate or triphenyl phosphate; the nano-reinforcing agent is carbon nanotubes or graphene nanoparticles, and the particle size range of the nano-reinforcing agent is 10-50 nm.

[0011] By adopting the above technical solution, the solvent is defined as acetone and xylene in a mass ratio of 60-70% acetone and 30-40% xylene. Acetone's excellent solubility in the matrix resin and other components, combined with xylene's ability to regulate the evaporation rate, synergistically dissolves and disperses the solid components, precisely controlling the coating viscosity. This provides suitable process conditions for uniform coating and subsequent curing. Dibutyltin dilaurate or triphenyl phosphate is selected as a heat stabilizer, utilizing its targeted heat stabilizing function to inhibit thermal oxidative degradation of the coating during curing and service, preventing component performance deterioration and ensuring the long-term stability of the coating structure and function. The nano-reinforcing agent is defined as carbon nanotubes or graphene nanoparticles, with a particle size range of 10-50 nm. The excellent mechanical properties and nanoscale size of these two types of nanomaterials synergistically construct a reinforcing network with the matrix resin and fillers, enhancing the internal mechanical support capacity of the coating and providing crucial assurance for optimizing the coating's mechanical properties.

[0012] Preferably, the modified polytetrafluoroethylene is polytetrafluoroethylene powder that has been surface-treated with a silane coupling agent, and its particle size ranges from 0.1 to 5 μm; the particle size range of the nano-silica or nano-alumina is 10 to 100 nm.

[0013] By adopting the above technical solution, the modified polytetrafluoroethylene (PTFE) is limited to PTFE powder surface-treated with a silane coupling agent, and its particle size range of 0.1-5 μm is clearly defined. The silane coupling agent improves the interfacial compatibility of PTFE with other components and reduces agglomeration. Combined with the dispersion adaptability of the powder within this particle size range, it ensures that PTFE is uniformly distributed in the coating and fully exerts its anti-adhesion properties, thereby guaranteeing the stable performance of the coating's core anti-adhesion properties. By limiting the particle size range of nano-silica or nano-alumina to 10-100 nm, the microscopic size advantage of the nanofillers within this particle size range is utilized to more accurately fill the internal voids of the coating, strengthen the synergistic effect with the matrix resin and nano-reinforcing agents, and further optimize the microstructure density of the coating.

[0014] Secondly, this application provides a method for preparing an anti-stick coating material for the surface of a squeeze roller, using the following technical solution: A method for preparing an anti-stick coating material for the surface of a squeeze roller includes the following steps: S1. Surface pretreatment of the substrate: The surface of the squeeze roller is sandblasted with brown corundum to control the surface roughness between Ra1.5μm and 2.5μm. Then, a two-stage solvent cleaning is performed: first, xylene is used for wiping, and then acetone is used for ultrasonic cleaning for 10-15 minutes. S2. Raw material pretreatment and predispersion: The nano-reinforcing agent and one-third of the leveling agent are premixed under high-speed shear at a speed of 5000-8000 rpm for 5-10 minutes to form a slurry; at the same time, the modified polytetrafluoroethylene and filler are vacuum dried at 75-85℃ for 3-4 hours. S3. Graded mixing: First, mix the matrix resin and solvent at a stirring speed of 300-400 rpm for 20-30 min. Then, add the pre-dispersed nano-reinforcing agent slurry and increase the stirring speed to 800-1200 rpm to continue dispersing for 15-20 min. S4. Sequential addition and high-frequency intermittent ultrasound: Add modified polytetrafluoroethylene and additives sequentially to the mixture obtained in S3, and treat it at an ultrasonic frequency of 20-40kHz for 35-45min. S5. Vacuum degassing: Add filler and heat stabilizer to the mixture obtained in S4, and degas at a vacuum of 0.08-0.095 MPa while stirring at 400-500 rpm. S6. Controlled coating: The coating material obtained in step S5 is applied to the surface of the squeeze roller by spraying, and the wet film thickness is controlled to be 130-150μm. S7, Stepped Curing: The coated extrusion roller is placed in a programmed temperature-controlled environment and pre-curing, intermediate curing and final curing are performed in sequence; S8. Post-treatment: Allow the cured coating to cool naturally to room temperature, and then use a step-by-step polishing process, polishing with 400-grit, 800-grit, and 1200-grit sandpaper in sequence to finally obtain an anti-adhesion surface with a surface roughness Ra of less than 0.3μm.

[0015] By employing the above technical solutions, the pretreatment of the substrate surface using brown fused alumina sandblasting combined with two-stage solvent cleaning achieves the dual effect of increasing the surface roughness of the substrate and thoroughly cleaning oil stains. The high-speed shearing premixing of the nano-reinforcing agent and a portion of the leveling agent breaks down the agglomeration of nanoparticles and forms a stable dispersion slurry. The staged mixing process—first mixing the matrix resin at low speed, then introducing the nano-slurry and increasing the rotation speed—ensures both complete resin dissolution and uniform dispersion of the nano-phase. The process of sequentially adding modified polytetrafluoroethylene and additives followed by intermittent ultrasonic treatment... This process serves to construct the composite material system step by step and prevent local overheating; by performing vacuum degassing while maintaining stirring, it removes air bubbles from the system without causing component separation; by controlling the wet film thickness and spraying parameters, it forms a uniform and drip-free initial coating; by setting a curing regime with multiple heating programs and holding stages, it promotes orderly cross-linking of the resin and releases internal stress; and finally, by polishing with progressively increasing sandpaper grit, it reduces surface roughness and eliminates microscopic defects, thus achieving a preparation process with close integration of each process step.

[0016] Preferably, in step S3, the entire process of staged mixing is carried out under the protection of an inert gas, which is nitrogen or argon.

[0017] By employing the above technical solution, an inert gas such as nitrogen or argon is continuously introduced during the staged mixing process to create a protective atmosphere, effectively isolating the matrix resin from oxygen. This protective measure effectively prevents the matrix resin from contacting oxygen in the air during mechanical stirring, avoiding oxidative degradation of the resin molecular chains. Simultaneously, the inert gas environment reduces oxidation reactions on the surface of the nano-reinforcing agents, maintaining their original surface properties. This protective mechanism provides a stable reaction environment for the entire mixing process, allowing resin dissolution and nanoparticle dispersion to occur under oxygen-free conditions, thereby ensuring the chemical stability of the material system.

[0018] Preferably, in step S4, the ultrasonic dispersion treatment adopts an intermittent mode, that is, after 5-10 minutes of ultrasonic treatment, it is paused for 2-5 minutes, and the process is repeated.

[0019] By employing the above technical solution, this periodic operation mode allows the system to dissipate heat and rebalance during the pause phase after acquiring sufficient dispersion energy during the ultrasonic treatment phase. The intermittent operation mode effectively avoids localized overheating caused by continuous ultrasound, preventing resin system denaturation or excessive solvent evaporation due to excessive temperature. Simultaneously, this pulsed energy supply method facilitates the redistribution of the dispersed material within the sound field, creating more favorable dispersion conditions for the next ultrasonic treatment. This control strategy achieves precise regulation of the dispersion process by adjusting the spatiotemporal distribution of energy input.

[0020] Preferably, in step S5, mechanical vibration is applied simultaneously during the degassing treatment, with a vibration frequency of 50-100Hz, and the treatment lasts for 30-40 minutes.

[0021] By employing the above technical solution, a dual effect of promoting bubble migration and collapse is achieved. This composite treatment method utilizes the periodic force generated by mechanical vibration to effectively disrupt the surface tension of bubbles and accelerate their movement towards the liquid surface. Vibrational energy within a specific frequency range can be transmitted into the coating system, causing the trapped bubbles to resonate and thus more easily detach from the solid surface. Simultaneously, the vibration also maintains the uniform suspension of all components within the system, preventing filler sedimentation or phase separation during degassing. This synergistic treatment method achieves effective elimination of micron-sized bubbles through physical field coupling.

[0022] Preferably, in step S6, the spraying is performed using high-pressure airless spraying with a spraying pressure of 10-20 MPa.

[0023] By employing the above technical solution, efficient atomization and uniform coverage of the coating material are achieved. This spraying method utilizes a high-pressure pump to pressurize the coating material and then release it instantaneously through a specially designed nozzle, forming extremely fine atomized particles without the need for compressed air assistance. The enormous kinetic energy generated by the high-pressure jet ensures excellent penetration and adhesion of the coating particles to the substrate surface, while avoiding the uneven coating caused by airflow disturbances in traditional air spraying. The setting of a specific pressure range ensures sufficient atomization of the material while preventing paint rebound loss due to excessive pressure. This controlled coating method provides process assurance for forming a uniform and dense wet film layer.

[0024] Preferably, in step S7, the pre-curing temperature is 80-110℃, and the holding time is 10-30 min; the intermediate curing temperature is 150-180℃, and the holding time is 1-2 h; the final curing temperature is 200-220℃, and the holding time is 0.5-1 h, and the final curing is carried out under nitrogen protection, and the temperature rise rate of the programmed temperature control is 2-5℃ / min.

[0025] By employing the above technical solution, a deep cross-linking reaction is achieved while preventing thermo-oxidative aging of the material. This segmented curing temperature program design gradually increases the reaction energy barrier, ensuring the orderly progress of the resin cross-linking reaction and avoiding stress concentration and microscopic defects within the coating caused by rapid temperature changes. The nitrogen-protected environment effectively blocks the oxidative degradation of resin molecules by oxygen under high-temperature conditions, while the controllable heating rate ensures the synchronicity of the curing reaction in different areas of the coating, thereby achieving the integrity of the coating structure and the stability of its performance.

[0026] In summary, this application has the following beneficial effects: 1. This application uses a specific ratio of base resin, modified polytetrafluoroethylene, filler, additives, solvent, heat stabilizer and nano-reinforcing agent. Due to the synergistic effect between the components, a dense and stable composite coating structure is formed, which achieves excellent comprehensive anti-adhesion performance and mechanical durability. Through the reasonable combination of the components, this coating system enhances the structural integrity of the coating while maintaining good anti-adhesion properties, enabling it to adapt to the complex working environment of the squeeze roller.

[0027] 2. In this application, a specific weight ratio of sodium polycarboxylate and hydrogenated castor oil is preferably used as the additive system. At the same time, modified polytetrafluoroethylene treated with silane coupling agent is used. Due to the synergistic effect of this additive combination and surface modification technology, improved interfacial compatibility and dispersion stability are achieved. This design effectively improves the dispersion uniformity of each component in the system, enhances the bonding force inside the coating, and provides a guarantee for the stability of the coating performance.

[0028] 3. The method of this application, through a phased preparation process including raw material pre-dispersion, graded mixing, intermittent ultrasonic treatment and step-by-step curing, achieves a coating with uniform structure and stable performance due to the organic combination and parameter optimization of each process step. This step-by-step processing method ensures the full integration and orderly arrangement of the material components, providing a process basis for the reliability of coating quality. Attached Figure Description

[0029] Figure 1 This is a flowchart illustrating a method for preparing an anti-adhesion coating material for the surface of a squeeze roller, as provided in this application. Detailed Implementation

[0030] The present application will be further described in detail below with reference to embodiments and comparative examples. Unless otherwise specified, the experimental methods used below are conventional methods. Unless otherwise specified, the materials, reagents, methods and instruments used are all conventional materials, reagents, methods and instruments in the art, which can be obtained by those skilled in the art through commercial channels or prepared according to literature methods.

[0031] Technical concept: Existing anti-stick coatings for squeeze rollers struggle to simultaneously achieve both anti-stick performance and mechanical durability. The core reasons lie in the lack of targeted compatibility in component selection, insufficient compatibility between components, and unreasonable structural design: unmodified anti-stick components have weak interfacial bonding with the matrix resin and other components, making them prone to agglomeration or peeling; unbalanced solvent ratios lead to insufficient component dispersion, resulting in voids within the coating; the particle size of nanofillers and reinforcing agents is not precisely controlled, failing to effectively construct a dense and reinforced structure; and unclear types and ratios of additives make it difficult to coordinate component dispersion and coating formation. These factors collectively result in coatings that either have poor anti-stick performance or insufficient mechanical strength and stability, making them unsuitable for complex working conditions.

[0032] This technical solution addresses the aforementioned problems by constructing a synergistic and compatible coating system through a series of precise technical means: Modified polytetrafluoroethylene (PTFE) with a silane coupling agent surface treatment and a defined particle size range is selected to improve its compatibility with other components; epoxy resin or polyurethane resin is used as the matrix, combined with nano-silica, nano-alumina, carbon nanotubes, and nano-graphene of specific particle sizes to construct a dense microstructure with excellent mechanical properties; the solvent is defined as acetone and xylene in a specific ratio to ensure sufficient dissolution and dispersion of components; the additives are limited to sodium polycarboxylate and hydrogenated castor oil with a defined ratio to coordinate dispersion and leveling effects; a suitable heat stabilizer is selected and the particle size range of relevant components is controlled; simultaneously, through specific weight ratios of each component, all components achieve synergistic effects, ultimately constructing a composite coating with both excellent anti-adhesion properties and mechanical durability, thus solving the core defects of existing technologies.

[0033] Preparation Example 1 The preparation method of modified polytetrafluoroethylene is as follows: Commercial polytetrafluoroethylene (PTFE) powder with a particle size of 0.1-5 μm was added to a mixed solvent of ethanol and deionized water in a volume ratio of 1:1. The mixture was stirred and dispersed to form a suspension with a mass fraction of 10%. Then, 3% (by mass) of silane coupling agent KH-550 was added to the PTFE powder. The system temperature was raised to 60°C, and the reaction was carried out at a constant temperature of 300 rpm for 2 hours. During the reaction, the mixture was continuously stirred to ensure that the silane coupling agent uniformly covered the surface of the PTFE powder and that a grafting reaction occurred. After the reaction, the suspension was vacuum filtered, the filter cake was collected, and dried in a vacuum drying oven at 80°C for 4 hours to remove residual solvent. Finally, modified PTFE powder with a silane coupling agent surface treatment was obtained, and the particle size of the powder was maintained in the range of 0.1-5 μm.

[0034] The following are the main raw materials and reagents used in the preparation examples, embodiments, and comparative examples, and their sources and specifications are as follows; unless otherwise specified, all reagents are commercially available analytical grade or higher products: 0. The epoxy resin was purchased from Jinan Jingsheng Chemical Co., Ltd., CAS: 61788-97-4; 1. The polyurethane resin was purchased from Guangdong Wengjiang Chemical Reagent Co., Ltd., CAS: 9009-54-5; 2. Unmodified polytetrafluoroethylene powder was purchased from Henan Weitixi Chemical Technology Co., Ltd., CAS: 9002-84-0; 3. The silane coupling agent was purchased from Wuhan Jiyesheng Chemical Co., Ltd., item number: A00213; 4. Sodium polycarboxylate dispersant was purchased from Nantong Deyi Chemical Co., Ltd., CAS: 62601-60-9; 5. Hydrogenated castor oil was purchased from Shanghai Yuanye Biotechnology Co., Ltd., product number: S29765; 6. Xylene was purchased from Shandong Zhengxing New Materials Co., Ltd., CAS: 1330-20-7; 7. Dibutyltin dilaurate was purchased from Guangdong Wengjiang Chemical Reagent Co., Ltd., CAS: 77-58-7; 8. Triphenyl phosphate was purchased from Shanghai Yuanye Biotechnology Co., Ltd., product number: S24231.

[0035] Example 1 This application provides an anti-stick coating material for the surface of a squeeze roller, the coating material being composed of the following components in parts by weight: 40 parts of matrix resin, 15 parts of modified polytetrafluoroethylene, 10 parts of filler, 5 parts of additives, 30 parts of solvent, 3 parts of heat stabilizer, and 4.5 parts of nano-reinforcing agent; The matrix resin is epoxy resin; the filler is nano-silica; the additives include dispersant and leveling agent, the dispersant is sodium polycarboxylate, the leveling agent is hydrogenated castor oil, and the weight ratio of sodium polycarboxylate to hydrogenated castor oil is 2:1.

[0036] The solvent is composed of acetone and xylene, with a mass ratio of 65% acetone and 35% xylene; the heat stabilizer is dibutyltin dilaurate; the nano-reinforcing agent is carbon nanotubes, and the particle size range of the nano-reinforcing agent is 30 nm.

[0037] Among them, the modified polytetrafluoroethylene is polytetrafluoroethylene powder that has been surface-treated with a silane coupling agent, and its particle size range is 2.5 μm; the nano silica has a particle size range of 55 nm.

[0038] The method for preparing the anti-stick coating material on the surface of the squeeze roller mentioned above includes the following steps: S1. Surface pretreatment of the substrate: The surface of the squeeze roller is sandblasted with brown fused alumina to control the surface roughness at Ra2.0μm. Then, a two-stage solvent cleaning is performed: first, xylene is used for wiping, and then acetone is used for ultrasonic cleaning for 12.5 min. S2. Raw material pretreatment and predispersion: The nano-reinforcing agent and one-third of the amount of hydrogenated castor oil were premixed at 6500 rpm for 7.5 min under high-speed shearing to form a slurry; at the same time, the modified polytetrafluoroethylene and filler were vacuum dried at 80℃ for 3.5 h. S3, graded mixing: First, mix the matrix resin and solvent at a stirring speed of 350 rpm for 25 min, then add the pre-dispersed nano-reinforcing agent slurry, and increase the stirring speed to 1000 rpm and continue to disperse for 17.5 min; The entire staged mixing process is carried out under the protection of an inert gas, namely nitrogen. S4. Sequential addition and high-frequency intermittent ultrasound: Modified polytetrafluoroethylene, the remaining hydrogenated castor oil and all of the sodium polycarboxylate were added sequentially to the mixture obtained in S3, and the mixture was treated with ultrasound at a frequency of 30 kHz for 40 min. The ultrasonic dispersion treatment was performed in an intermittent mode, that is, ultrasonic treatment was paused for 3.5 minutes after 7.5 minutes, and the process was repeated. S5, Vacuum degassing: Add filler and heat stabilizer to the mixture obtained in S4, and degas at a vacuum of 0.0875 MPa while maintaining stirring at 450 rpm. During the degassing process, mechanical vibration was applied at a frequency of 75 Hz for 35 minutes. S6. Controlled coating: The coating material obtained in step S5 is applied to the surface of the squeeze roller by spraying, and the wet film thickness is controlled to be 140μm. The spraying process employs high-pressure airless spraying with a spraying pressure of 15MPa. S7, Stepped Curing: The coated extrusion roller is placed in a programmed temperature-controlled environment and pre-curing, intermediate curing and final curing are performed in sequence; The pre-curing temperature was 95℃, and the holding time was 20 min; the intermediate curing temperature was 165℃, and the holding time was 1.5 h; the final curing temperature was 210℃, and the holding time was 0.75 h. The final curing was carried out under nitrogen protection, and the temperature rise rate was 3.5℃ / min under programmed temperature control. S8. Post-treatment: Allow the cured coating to cool naturally to room temperature, and then use a step-by-step polishing process, polishing with 400-grit, 800-grit, and 1200-grit sandpaper in sequence to finally obtain an anti-adhesion surface with a surface roughness Ra of less than 0.3μm.

[0039] Example 2 This application provides an anti-stick coating material for the surface of a squeeze roller, the coating material being composed of the following components in parts by weight: 30 parts of matrix resin, 10 parts of modified polytetrafluoroethylene, 5 parts of filler, 2 parts of additives, 20 parts of solvent, 2 parts of heat stabilizer, and 3 parts of nano-reinforcing agent. The matrix resin is polyurethane resin; the filler is nano-alumina; the additives include dispersant and leveling agent, the dispersant is sodium polycarboxylate, the leveling agent is hydrogenated castor oil, and the weight ratio of sodium polycarboxylate to hydrogenated castor oil is 1.5:1.

[0040] The solvent is composed of acetone and xylene, with a mass ratio of 60% acetone and 40% xylene; the heat stabilizer is triphenyl phosphate; the nano-reinforcing agent is nano-graphene, and the particle size range of the nano-reinforcing agent is 10 nm.

[0041] Among them, the modified polytetrafluoroethylene is polytetrafluoroethylene powder that has been surface-treated with a silane coupling agent, and its particle size range is 0.1 μm; the nano-alumina has a particle size range of 10 nm.

[0042] The method for preparing the anti-stick coating material on the surface of the squeeze roller mentioned above includes the following steps: S1. Surface pretreatment of substrate: The surface of the squeeze roller is sandblasted with brown fused alumina to control the surface roughness at Ra1.5μm. Then, a two-stage solvent cleaning is performed: first, xylene is used for wiping, and then acetone is used for ultrasonic cleaning for 10 min. S2. Raw material pretreatment and predispersion: The nano-reinforcing agent and one-third of the amount of hydrogenated castor oil are premixed at 5000 rpm for 5 minutes under high-speed shearing to form a slurry; at the same time, the modified polytetrafluoroethylene and filler are vacuum dried at 75°C for 3 hours. S3, graded mixing: First, mix the matrix resin and solvent at a stirring speed of 300 rpm for 20 min, then add the pre-dispersed nano-reinforcing agent slurry, and increase the stirring speed to 800 rpm and continue to disperse for 15 min; The entire staged mixing process is carried out under the protection of an inert gas, namely argon. S4. Sequential addition and high-frequency intermittent ultrasound: Modified polytetrafluoroethylene, the remaining hydrogenated castor oil and all of the sodium polycarboxylate were added sequentially to the mixture obtained in S3, and the mixture was treated with ultrasound at a frequency of 20 kHz for 35 min. The ultrasonic dispersion treatment was performed in an intermittent mode, that is, after 5 minutes of ultrasonic treatment, a 2-minute pause was taken, and the process was repeated. S5. Vacuum degassing: Add filler and heat stabilizer to the mixture obtained in S4, and degas at a vacuum of 0.08 MPa while maintaining stirring at 400 rpm. During the degassing process, mechanical vibration was applied at a frequency of 50 Hz for 30 minutes. S6. Controlled coating: The coating material obtained in step S5 is applied to the surface of the squeeze roller by spraying, and the wet film thickness is controlled to be 130μm. The spraying process employs high-pressure airless spraying with a spraying pressure of 10MPa. S7, Stepped Curing: The coated extrusion roller is placed in a programmed temperature-controlled environment and pre-curing, intermediate curing and final curing are performed in sequence; The pre-curing temperature is 80℃, and the holding time is 10 min; the intermediate curing temperature is 150℃, and the holding time is 1 h; the final curing temperature is 200℃, and the holding time is 0.5 h. The final curing is carried out under nitrogen protection, and the temperature rise rate is 2℃ / min under programmed temperature control. S8. Post-treatment: Allow the cured coating to cool naturally to room temperature, and then use a step-by-step polishing process, polishing with 400-grit, 800-grit, and 1200-grit sandpaper in sequence to finally obtain an anti-adhesion surface with a surface roughness Ra of less than 0.3μm.

[0043] Example 3 This application provides an anti-stick coating material for the surface of a squeeze roller, the coating material being composed of the following components in parts by weight: 50 parts of matrix resin, 20 parts of modified polytetrafluoroethylene, 15 parts of filler, 8 parts of additives, 40 parts of solvent, 4 parts of heat stabilizer, and 6 parts of nano-reinforcing agent. The matrix resin is epoxy resin; the filler is nano-silica; the additives include dispersant and leveling agent, the dispersant is sodium polycarboxylate, the leveling agent is hydrogenated castor oil, and the weight ratio of sodium polycarboxylate to hydrogenated castor oil is 2.5:1.

[0044] The solvent is composed of acetone and xylene, with a mass ratio of 70% acetone and 30% xylene; the heat stabilizer is dibutyltin dilaurate; the nano-reinforcing agent is carbon nanotubes, and the particle size range of the nano-reinforcing agent is 50 nm.

[0045] Among them, the modified polytetrafluoroethylene is polytetrafluoroethylene powder that has been surface-treated with a silane coupling agent, and its particle size range is 5μm; the particle size range of nano silica is 100nm.

[0046] The method for preparing the anti-stick coating material on the surface of the squeeze roller mentioned above includes the following steps: S1. Surface pretreatment of the substrate: The surface of the squeeze roller is sandblasted with brown fused alumina to control the surface roughness at Ra2.5μm. Then, a two-stage solvent cleaning is performed: first, xylene is used for wiping, and then acetone is used for ultrasonic cleaning for 15 minutes. S2. Raw material pretreatment and predispersion: The nano-reinforcing agent and one-third of the amount of hydrogenated castor oil are premixed at 8000 rpm for 10 min under high-speed shearing to form a slurry; at the same time, the modified polytetrafluoroethylene and filler are vacuum dried at 85℃ for 4 h. S3, graded mixing: First, mix the matrix resin and solvent at a stirring speed of 400 rpm for 30 min, then add the pre-dispersed nano-reinforcing agent slurry, and increase the stirring speed to 1200 rpm and continue to disperse for 20 min; The entire staged mixing process is carried out under the protection of an inert gas, namely nitrogen. S4. Sequential addition and high-frequency intermittent ultrasound: Modified polytetrafluoroethylene, the remaining hydrogenated castor oil and all of the sodium polycarboxylate were added sequentially to the mixture obtained in S3, and the mixture was treated with ultrasound at a frequency of 40 kHz for 45 min. The ultrasonic dispersion treatment was performed in an intermittent mode, that is, after 10 minutes of ultrasonic treatment, a 5-minute pause was taken, and the process was repeated. S5. Vacuum degassing: Add filler and heat stabilizer to the mixture obtained in S4, and degas at a vacuum of 0.095 MPa while maintaining stirring at 500 rpm. During the degassing process, mechanical vibration was applied at a frequency of 100 Hz for 40 minutes. S6. Controlled coating: The coating material obtained in step S5 is applied to the surface of the squeeze roller by spraying, and the wet film thickness is controlled to be 150μm. The spraying process employs high-pressure airless spraying with a spraying pressure of 20MPa. S7, Stepped Curing: The coated extrusion roller is placed in a programmed temperature-controlled environment and pre-curing, intermediate curing and final curing are performed in sequence; The pre-curing temperature is 110℃ and the holding time is 30 min; the intermediate curing temperature is 180℃ and the holding time is 2 h; the final curing temperature is 220℃ and the holding time is 1 h. The final curing is carried out under nitrogen protection, and the temperature rise rate is 5℃ / min. S8. Post-treatment: Allow the cured coating to cool naturally to room temperature, and then use a step-by-step polishing process, polishing with 400-grit, 800-grit, and 1200-grit sandpaper in sequence to finally obtain an anti-adhesion surface with a surface roughness Ra of less than 0.3μm.

[0047] Comparative Example 1 The only difference between this comparative example and Example 1 is that the coating material does not contain a nano-reinforcing agent. All other raw material compositions and preparation methods are the same as in Example 1.

[0048] Comparative Example 2 The only difference between this comparative example and Example 1 is that the anti-adhesion agent used is ordinary polytetrafluoroethylene powder without silane coupling agent surface treatment. All other raw material compositions and preparation methods are the same as in Example 1.

[0049] Comparative Example 3 The only difference between this comparative example and Example 1 is that the nano-reinforcing agent uses nano-clay instead of carbon nanotubes. All other raw material compositions and preparation methods are the same as in Example 1.

[0050] Comparative Example 4 The only difference between this comparative example and Example 1 is that the coating material does not contain a heat stabilizer. All other raw material composition and preparation methods are the same as in Example 1.

[0051] Comparative Example 5 The only difference between this comparative example and Example 1 is that in step S4, the ultrasonic dispersion treatment is performed in a continuous mode, and the total treatment time remains 40 minutes. All other raw material compositions and preparation steps are the same as in Example 1.

[0052] Comparative Example 6 The only difference between this comparative example and Example 1 is that in step S7, the stepped curing process is changed to a one-step curing process, that is, the coated extrusion roller is directly cured at 210°C for 2.25 hours without programmed heating or staged heat preservation, and without nitrogen protection. The remaining raw material composition and preparation steps are the same as in Example 1.

[0053] I. Anti-adhesion performance test Referring to the test principle of ASTM D3359 "Test Method for Peel Strength of Pressure-Sensitive Adhesive Tape" and combined with the actual working conditions of the squeeze roller, the anti-adhesion performance of the coating is evaluated by measuring the separation force between the silicone rubber and the coating. The smaller the separation force, the better the anti-adhesion performance.

[0054] Coating samples from Examples 1-3 and Comparative Examples 1-6 were selected and processed into test blocks measuring 100mm × 50mm × substrate thickness, ensuring the coating surface was defect-free and the roughness Ra ≤ 0.3μm. Before testing, the samples were equilibrated for 24 hours at 23℃ and 50% relative humidity, fixed on a temperature-controlled testing platform, and the coating surface temperature was stabilized at 80℃ ± 1℃. Silicone rubber with a Shore hardness of A50 and a thickness of 2mm was selected as the test material, cut into 50mm × 50mm pieces, and applied to the coating surface. A constant pressure of 0.1MPa was applied using a pressure loading device, and the contact was maintained for 10 minutes. A tensile testing machine with an accuracy of 0.5 grade was used to vertically separate the silicone rubber from the coating at a speed of 50mm / min, and the maximum separation force was recorded in N. Each sample was tested four times, and the average value was taken after removing extreme values. The laboratory environment was controlled at 23℃ ± 2℃ and 50% ± 5% relative humidity throughout the testing process, and the same operator used the same equipment to ensure consistent conditions.

[0055] II. Abrasion Resistance Test According to ASTM D4060, "Standard Test Method for Determining the Abrasion Resistance of Organic Coatings by Tabor Abrasion Tester", abrasion resistance is evaluated by measuring the mass loss of the coating before and after wear. The smaller the mass loss, the better the abrasion resistance.

[0056] The coating samples from Examples 1-3 and Comparative Examples 1-6 were processed into circular blocks with a diameter of 100 mm. Before testing, they were equilibrated for 24 hours at 23°C and 50% relative humidity, and their initial mass was measured using a precision balance with an accuracy of 0.001 mg. The samples were fixed on the rotating platform of a Taber abrasion testing machine, using a CS-10 grinding wheel, with a constant load of 500 g, a rotation speed of 60 rpm, and continuous friction for 1000 rpm. The machine was stopped every 200 rpm to clean the abrasive debris. After the test, the samples were equilibrated again for 1 hour and their mass was measured, and the mass loss was calculated. All samples were tested using the same calibrated testing machine, operated by the same operator according to the same procedure, to ensure load accuracy and rotation speed stability, eliminate interference from equipment and human factors on the test results, and ensure consistency of test conditions for all examples and comparative examples, making the test data authentic and reliable, and facilitating comparative analysis.

[0057] III. Adhesion Test The cross-cut test method in ASTM D3359 "Test Method for Peel Strength of Pressure Sensitive Adhesive Tapes" is used to evaluate the bonding strength between the coating and the substrate, which indirectly reflects the service stability of the coating under complex working conditions.

[0058] Coating samples from Examples 1-3 and Comparative Examples 1-6 were cut into 150mm × 150mm blocks, ensuring the surface was dry and clean. Using a crisscross tool equipped with a 0.1mm thick carbide blade, 100 1mm × 1mm grids were drawn on the coating surface, penetrating the coating to the substrate. Pressure-sensitive tape (10N / 25mm adhesion) specified in ASTM D3359 was used to cover the grid area, and a 2kg standard roller was used to roll it back and forth twice to ensure adhesion. After standing for 1 minute, the tape was quickly peeled off at a 60-degree angle. The coating peeling was observed using a 10x magnifying glass and rated according to the ASTM D3359 rating chart, ranging from 0B to 5B, where 5B represents no peeling. Three tests were conducted on different areas of each sample, and the average was taken. Tests were performed in a clean environment to avoid impurities affecting the accuracy of the results.

[0059] The performance test data of the anti-adhesion coating on the surface of the squeeze rolls of Examples 1-3 and Comparative Examples 1-6 are shown in Table 1.

[0060] Table 1:

[0061] As can be seen from Examples 1-3 and Comparative Example 1, and in conjunction with Table 1, the introduction of nano-reinforcing agents significantly improves the structural integrity and surface properties of the coating. When nano-reinforcing components are lacking in the material system, the density and mechanical strength of the coating are significantly insufficient, which directly affects its performance in frictional contact and interfacial bonding.

[0062] As can be seen from Examples 1-3 and Comparative Example 2, and in conjunction with Table 1, the surface modification treatment of polytetrafluoroethylene (PTFE) powder has a crucial impact on the interfacial bonding quality of the coating. Untreated PTFE particles exhibit poor compatibility with the matrix resin, leading to weak areas within the coating and thus affecting the overall bonding stability.

[0063] As can be seen from Examples 1-3 and Comparative Example 3, and in conjunction with Table 1, the choice of nano-reinforcing agent has a significant impact on coating performance. Different morphologies and properties of nanomaterials exhibit variations in dispersion and interfacial bonding within the matrix, which directly affects the final overall performance of the coating.

[0064] As can be seen from Examples 1-3 and Comparative Example 4, and in conjunction with Table 1, the addition of a heat stabilizer has a significant impact on the durability of the coating. Under thermomechanical stress, an appropriate heat stabilization system can effectively maintain the stability of the coating components and prevent premature degradation of material properties.

[0065] As can be seen from Examples 1-3 and Comparative Example 5, and in conjunction with Table 1, the ultrasonic dispersion process plays a decisive role in the uniformity of filler dispersion in the matrix. Continuous ultrasonic mode is prone to local overheating and uneven energy distribution, affecting the dispersion quality of nanoparticles and thus altering the microstructure of the coating.

[0066] As can be seen from Examples 1-3 and Comparative Example 6, and in conjunction with Table 1, the optimized design of the curing process is crucial to the coating's molding quality. A reasonable stepped heating program is beneficial for solvent evaporation and the orderly arrangement of molecular chain segments, while simplifying the curing process can affect the crosslinking density and internal stress distribution of the coating.

[0067] This specific embodiment is merely an explanation of this application and is not intended to limit it. After reading this specification, those skilled in the art can make modifications to this embodiment without contributing any inventive step, but such modifications are protected by patent law as long as they fall within the scope of the claims of this application.

Claims

1. A surface anti-sticking coating material for a squeeze roller, characterized in that: The coating material is composed of the following components by weight: 30-50 parts of matrix resin, 10-20 parts of modified polytetrafluoroethylene, 5-15 parts of filler, 2-8 parts of additives, 20-40 parts of solvent, 2-4 parts of heat stabilizer, and 3-6 parts of nano-reinforcing agent.

2. The surface anti-adhesion coating material of a squeeze roller according to claim 1, characterized in that: The matrix resin is epoxy resin or polyurethane resin; the filler is nano-silica or nano-alumina; the additives include dispersant and leveling agent, the dispersant is sodium polycarboxylate, the leveling agent is hydrogenated castor oil, and the weight ratio of sodium polycarboxylate to hydrogenated castor oil is 1.5:1 to 2.5:

1.

3. The surface anti-adhesion coating material of a squeeze roller according to claim 1, characterized in that: The solvent is composed of acetone and xylene, with a mass ratio of 60-70% acetone and 30-40% xylene; the heat stabilizer is dibutyltin dilaurate or triphenyl phosphate; the nano-reinforcing agent is carbon nanotubes or graphene nanoparticles, and the particle size range of the nano-reinforcing agent is 10-50 nm.

4. The surface anti-adhesion coating material of a squeeze roller according to claim 1, characterized in that: The modified polytetrafluoroethylene is polytetrafluoroethylene powder that has been surface-treated with a silane coupling agent, and its particle size ranges from 0.1 to 5 μm; the nano-silica or nano-alumina has a particle size range of 10 to 100 nm.

5. A method for preparing an anti-stick coating material for the surface of a squeeze roller, characterized in that, A surface anti-stick coating material for a squeeze roller according to any one of claims 1-4 includes the following steps: S1. Surface pretreatment of the substrate: The surface of the squeeze roller is sandblasted with brown corundum to control the surface roughness between Ra1.5μm and 2.5μm. Then, a two-stage solvent cleaning is performed: first, xylene is used for wiping, and then acetone is used for ultrasonic cleaning for 10-15 minutes. S2. Raw material pretreatment and predispersion: The nano-reinforcing agent and one-third of the leveling agent are premixed under high-speed shear at a speed of 5000-8000 rpm for 5-10 minutes to form a slurry; at the same time, the modified polytetrafluoroethylene and filler are vacuum dried at 75-85℃ for 3-4 hours. S3. Graded mixing: First, mix the matrix resin and solvent at a stirring speed of 300-400 rpm for 20-30 min. Then, add the pre-dispersed nano-reinforcing agent slurry and increase the stirring speed to 800-1200 rpm to continue dispersing for 15-20 min. S4. Sequential addition and high-frequency intermittent ultrasound: Add modified polytetrafluoroethylene and additives sequentially to the mixture obtained in S3, and treat it at an ultrasonic frequency of 20-40kHz for 35-45min. S5. Vacuum degassing: Add filler and heat stabilizer to the mixture obtained in S4, and degas at a vacuum of 0.08-0.095 MPa while stirring at 400-500 rpm. S6. Controlled coating: The coating material obtained in step S5 is applied to the surface of the squeeze roller by spraying, and the wet film thickness is controlled to be 130-150μm. S7, Stepped Curing: The coated extrusion roller is placed in a programmed temperature-controlled environment and pre-curing, intermediate curing and final curing are performed in sequence; S8. Post-treatment: Allow the cured coating to cool naturally to room temperature, and then use a step-by-step polishing process, polishing with 400-grit, 800-grit, and 1200-grit sandpaper in sequence to finally obtain an anti-adhesion surface with a surface roughness Ra of less than 0.3μm.

6. The method for preparing a surface anti-adhesion coating material for a squeeze roller according to claim 5, characterized in that: In step S3, the entire staged mixing process is carried out under the protection of an inert gas, which is either nitrogen or argon.

7. The method for preparing a surface anti-adhesion coating material for a squeeze roller according to claim 5, characterized in that: In step S4, the ultrasonic dispersion treatment adopts an intermittent mode, that is, after 5-10 minutes of ultrasonic treatment, it is paused for 2-5 minutes, and the process is repeated.

8. The method for preparing a surface anti-adhesion coating material for a squeeze roller according to claim 5, characterized in that: In step S5, mechanical vibration is applied simultaneously during the degassing process, with a vibration frequency of 50-100Hz, for 30-40 minutes.

9. The method for preparing a surface anti-adhesion coating material for a squeeze roller according to claim 5, characterized in that: In step S6, the spraying is carried out using high-pressure airless spraying with a spraying pressure of 10-20 MPa.

10. A method for preparing a surface anti-adhesion coating material for a squeeze roller according to claim 5, characterized in that: In step S7, the pre-curing temperature is 80-110℃, and the holding time is 10-30 min; the intermediate curing temperature is 150-180℃, and the holding time is 1-2 h; the final curing temperature is 200-220℃, and the holding time is 0.5-1 h, and the final curing is carried out under nitrogen protection, and the temperature rise rate of the programmed temperature control is 2-5℃ / min.

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