A high wear-resistant porous damping fabric and its preparation process

Abstract

This invention discloses a high-wear-resistant porous damping cloth and its preparation process, belonging to the technical field of polymer composite materials and precision polishing materials. Addressing the problems of insufficient wear resistance and the tendency of rigid fillers to affect the stability of the pore structure in existing damping cloths, this invention uses bisphenol A epoxy resin and polyetheramine to synergistically modify boehmite, and then combines it with polyester polyurethane resin, N,N-dimethylformamide, polyethylene glycol, polyvinylpyrrolidone, and other additives. The damping cloth is prepared through slurry preparation, coating, wet coagulation, washing, drying, and surface treatment. This invention can improve the dispersion and interfacial bonding of boehmite in polyurethane, thereby enhancing the wear resistance, pore structure stability, compression resilience, and mechanical properties of the damping cloth, and has good application value.

Description

Technical Field

[0001] This invention relates to the field of polymer composite materials and precision polishing materials, specifically to a high wear-resistant porous damping cloth and its preparation process. Background Technology

[0002] Damping cloth is a type of precision machining material with polyurethane as the main functional layer, featuring a porous structure and certain compression resilience. It is widely used in the grinding and polishing of optical glass, ceramics, crystal materials, and other precision components. In practical applications, the porous polyurethane functional layer can store and transport polishing fluid, and its elastic deformation buffers the contact stress between the workpiece and the polishing equipment, resulting in a more uniform processing effect on the workpiece surface. Existing damping cloths are typically prepared using a wet coagulation process. This involves dissolving polyurethane resin in an organic solvent and adding pore-forming agents to form a slurry. The slurry is then coated onto the surface of the base fabric and placed in a coagulation bath. The exchange between the solvent and non-solvent induces phase separation in the polyurethane, thereby forming the porous polyurethane functional layer.

[0003] As precision machining demands increasingly higher polishing efficiency, surface quality, and processing stability, damping cloths typically need to operate for extended periods under high rotational speeds and continuous friction. Porous polyurethane functional layers are prone to pore wall wear, surface damage, particle shedding, and localized pore collapse, leading to changes in the damping cloth's thickness and surface morphology. This, in turn, affects the retention and delivery capacity of the polishing slurry, resulting in decreased polishing stability and a shortened service life. Therefore, improving the wear resistance of porous polyurethane functional layers is a crucial approach to enhancing the overall performance of damping cloths.

[0004] Existing technologies typically improve the hardness and wear resistance of polyurethane materials by increasing the degree of crosslinking or by adding inorganic reinforcing materials such as alumina and silica. However, directly adding rigid inorganic materials can easily lead to agglomeration due to insufficient interfacial compatibility between the inorganic phase and the polyurethane matrix. This can also cause particle shedding and interfacial microcracks during continuous friction. Furthermore, the introduction of rigid particles can affect the mass transfer and phase separation behavior between the solvent and non-solvent during the wet coagulation process of the polyurethane slurry, reducing the uniformity of the formed pore structure. Further improving wear resistance by increasing the amount of inorganic materials or increasing the degree of polyurethane crosslinking can easily result in excessively high hardness of the porous functional layer, decreased flexibility and compression resilience, making it difficult to balance wear resistance and porous damping performance.

[0005] Therefore, how to improve the interfacial bonding between the wear-resistant reinforcing material and the polyurethane matrix, while improving the wear resistance of the porous polyurethane functional layer and reducing the adverse effects of the rigid reinforcing material on the wet pore formation process and the flexibility of the pore walls, so that the damping cloth can maintain a relatively stable porous structure, good compression resilience and long service life, is a technical problem that still needs to be solved for existing high wear-resistant porous damping cloths. Summary of the Invention

[0006] To overcome the problems in the aforementioned background technology, such as insufficient wear resistance of porous polyurethane functional layers, poor interfacial compatibility between rigid inorganic reinforcing materials and polyurethane matrices, and the difficulty in simultaneously achieving wear resistance, porous structure stability, and compression resilience, the present invention aims to provide a high-wear-resistant porous damping fabric and its preparation process. This invention uses epoxy-polyetheramine synergistic modification of boehmite as the wear-resistant reinforcing material. Through synergistic interfacial modification of boehmite using bisphenol A epoxy resin and polyetheramine, an organic interfacial layer with good compatibility and flexible transition is constructed between the boehmite and the polyurethane matrix. This layer is then compounded with polyester polyurethane resin, polyethylene glycol, polyvinylpyrrolidone, sodium dodecyl sulfate, castor oil, fumed silica, and an organosilicon defoamer. A porous polyurethane functional layer is formed through wet solidification, allowing the modified boehmite to be uniformly dispersed in the polyurethane matrix. This not only provides rigidity reinforcement and wear resistance but also reduces the adverse effects of inorganic particle agglomeration and interfacial stress concentration on the pore wall structure, maintaining a relatively uniform and stable porous structure.

[0007] The objective of this invention can be achieved through the following technical solutions: A highly wear-resistant porous damping fabric includes a base fabric and a porous polyurethane functional layer formed on the surface of the base fabric. The porous polyurethane functional layer comprises the following raw materials in parts by weight: 100-150 parts of polyester polyurethane resin; 6-20 parts of epoxy-polyetheramine synergistic modified boehmite; 80-150 parts of N,N-dimethylformamide; 4-12 parts of polyethylene glycol; 1-5 parts of polyvinylpyrrolidone; 0.2-1.0 parts of sodium dodecyl sulfate; 1-5 parts of castor oil; 1-4 parts of fumed silica; and 0.1-0.5 parts of silicone defoamer. The epoxy-polyetheramine synergistic modified boehmite is prepared by synergistic modification of boehmite with bisphenol A type epoxy resin and polyetheramine.

[0008] Optionally, the epoxy-polyetheramine synergistic modification of boehmite comprises the following raw materials in parts by weight: 100 parts boehmite; 5-12 parts bisphenol A type epoxy resin; 3-8 parts polyetheramine; 120-200 parts ethanol; and 50-100 parts deionized water.

[0009] Optionally, the preparation method of epoxy-polyetheramine synergistic modification of boehmite includes the following steps: (1) Boehmite was added to a mixed solvent of ethanol and deionized water, stirred and ultrasonically dispersed to obtain a boehmite dispersion; (2) Add bisphenol A type epoxy resin to the boehmite dispersion and stir to obtain epoxy pre-modified boehmite dispersion. (3) Add polyetheramine to the epoxy premodified boehmite dispersion and stir to react. After the reaction is completed, centrifuge, wash, vacuum dry and grind to obtain epoxy-polyetheramine synergistic modified boehmite.

[0010] Optionally, the reaction conditions in step (1) are: stirring speed of 900-1100 r / min, stirring time of 25-35 min; ultrasonic dispersion power of 300-500 W, ultrasonic dispersion time of 20-30 min, and dispersion temperature of 25-35 °C.

[0011] Optionally, the reaction conditions in step (2) are a reaction temperature of 70-80℃, a stirring speed of 550-750r / min, and a reaction time of 2.5-3.5h.

[0012] Optionally, the reaction conditions in step (3) are: reaction temperature of 65-75℃, stirring speed of 450-650 r / min, and reaction time of 3-4 h; after the reaction is completed, centrifuge at 6000-8000 r / min for 8-12 min, wash with ethanol and deionized water 2-3 times in sequence, vacuum dry at 65-75℃ and vacuum degree of -0.08--0.095 MPa for 8-10 h, and grind to an average particle size of 1-5 μm.

[0013] Optionally, a method for preparing a highly wear-resistant porous damping fabric includes the following steps: S1, polyester polyurethane resin is added to N,N-dimethylformamide and stirred to dissolve. Then, epoxy-polyetheramine synergistic modified boehmite, polyethylene glycol, polyvinylpyrrolidone, sodium dodecyl sulfate, castor oil, fumed silica and organosilicon defoamer are added in sequence. After stirring, dispersion and vacuum degassing, polyurethane composite slurry is obtained. S2, the obtained polyurethane composite slurry is uniformly coated on the surface of the base fabric, and the coated base fabric is immersed in the coagulation bath for wet coagulation, so that the polyurethane undergoes phase separation and forms a porous polyurethane functional layer to obtain the damping fabric blank. S3. The obtained damping cloth blank is washed and dried, and then the porous polyurethane functional layer is sanded, sized and leveled to obtain a high wear-resistant porous damping cloth.

[0014] Optionally, the reaction conditions for step S1 are as follows: the polyester polyurethane resin is stirred and dissolved at 40-55°C and 400-600 r / min for 40-60 min; after adding the remaining raw materials, it is dispersed at 800-1200 r / min for 30-50 min; after dispersion, it is degassed at a vacuum of -0.08 to -0.095 MPa for 15-25 min.

[0015] Optionally, the reaction conditions in step S2 are as follows: the coating thickness of the polyurethane composite slurry is 0.6–1.2 mm; the coagulation bath is composed of N,N-dimethylformamide and water, wherein the mass concentration of N,N-dimethylformamide is 5–15%, the coagulation bath temperature is 20–30 °C, and the wet coagulation time is 15–30 min.

[0016] Optionally, the reaction conditions for step S3 are as follows: washing with deionized water at 20-30°C 3-5 times, each wash lasting 5-10 minutes; then drying at 100-130°C for 20-40 minutes; and after drying, the porous polyurethane functional layer is subjected to abrasion, thickness determination, and leveling treatment.

[0017] The beneficial effects of this invention are: This invention employs bisphenol A epoxy resin and polyetheramine to synergistically modify boehmite. The bisphenol A epoxy resin forms an organic interface layer on the boehmite surface, and flexible polyether segments are introduced into the boehmite interface through a ring-opening reaction between the amino and epoxy groups in the polyetheramine. This creates a buffered organic-inorganic transition interface between the rigid boehmite and the flexible polyurethane matrix. This interface improves the dispersion and interfacial bonding of boehmite in the polyurethane system, reduces particle agglomeration, and minimizes particle shedding and microcracks in the pore walls caused by interfacial stress concentration during friction. This allows the boehmite to stably perform its load-bearing and wear-resistant reinforcing functions. Simultaneously, the flexible polyether segments mitigate the adverse effects of rigid inorganic particles on the flexibility of the polyurethane pore walls and help maintain the interfacial stability of the system during wet solidification. Therefore, while improving the wear resistance of the porous polyurethane functional layer, it maintains good pore structure integrity and compression resilience, achieving a synergistic improvement in wear resistance and porous damping performance. Attached Figure Description

[0018] The invention will now be further described with reference to the accompanying drawings.

[0019] Figure 1 This is a comparison chart of the wear resistance test results for samples with different formulation ratios. Detailed Implementation

[0020] The present invention will be further described below with reference to specific embodiments. However, the present invention is not limited to the following embodiments. Equivalent adjustments made without departing from the spirit and essence of the present invention should also be considered to fall within the protection scope of the present invention.

[0021] Example 1: The purpose of this example is to provide a method for preparing highly wear-resistant porous damping fabric under conditions of low modifier dosage and low functional additive dosage, to verify the effect of epoxy-polyetheramine synergistic modification of boehmite on wear resistance enhancement and pore structure maintenance of porous polyurethane functional layers at low addition levels.

[0022] S1. Preparation of epoxy-polyetheramine synergistic modified boehmite: 100 parts of boehmite were added to a mixed solvent consisting of 120 parts of ethanol and 50 parts of deionized water, stirred at 900 r / min for 25 min, and then ultrasonically dispersed at 300 W ultrasonic power and 25 °C for 20 min to obtain a boehmite dispersion; 5 parts of bisphenol A type epoxy resin were added to the obtained boehmite dispersion, and stirred at 70 °C and 550 r / min for 2.5 h to obtain an epoxy pre-modified boehmite dispersion; 3 parts of polyetheramine were added to the obtained epoxy pre-modified boehmite dispersion, and stirred at 65 °C and 450 r / min for 3 h to obtain a pre-modified boehmite dispersion; after the reaction was completed, the dispersion was centrifuged at 6000 r / min for 8 min, washed twice with ethanol and deionized water, vacuum dried at 65 °C and -0.08 MPa for 8 h, and ground to an average particle size of 1 μm to obtain epoxy-polyetheramine synergistic modified boehmite.

[0023] S2. Preparation and wet coagulation of polyurethane composite slurry: 100 parts of polyester-type polyurethane resin were added to 80 parts of N,N-dimethylformamide and stirred at 40℃ and 400 r / min for 40 min to dissolve. Then, 6 parts of epoxy-polyetheramine synergistic modified boehmite obtained in step S1, 4 parts of polyethylene glycol, 1 part of polyvinylpyrrolidone, 0.2 parts of sodium dodecyl sulfate, 1 part of castor oil, 1 part of fumed silica, and 0.1 parts of silicone defoamer were added sequentially and stirred at 800 r / min. The mixture was dispersed for 30 min under the specified conditions and then degassed for 15 min under a vacuum of -0.08 MPa to obtain a polyurethane composite slurry. The obtained polyurethane composite slurry was uniformly coated onto the surface of the base fabric, with the coating thickness controlled at 0.6 mm. The coated base fabric was then immersed in a 5% N,N-dimethylformamide-water coagulation bath and wet-coagulated at 20 °C for 15 min to allow the polyurethane to undergo phase separation and form a porous polyurethane functional layer, thus obtaining the damping fabric blank.

[0024] S3. Post-treatment: The damping cloth blank obtained in step S2 is washed three times with deionized water at 20°C for 5 minutes each time to remove residual N,N-dimethylformamide and water-soluble components; then it is dried at 100°C for 20 minutes, and the porous polyurethane functional layer is then sanded, sized and leveled to obtain the high wear-resistant porous damping cloth.

[0025] Example 2: The purpose of this example is to provide a high wear-resistant porous damping cloth with the proportions of each raw material and the preparation process parameters in the middle of the range. Through the synergistic effect between the boehmite and the polyurethane porous system modified by an appropriate amount of epoxy-polyetheramine, the wear resistance of the porous polyurethane functional layer is improved while taking into account the uniformity of the pore structure and the compression resilience.

[0026] S1. Preparation of epoxy-polyetheramine synergistic modification of boehmite: 100 parts of boehmite were added to a mixed solvent consisting of 160 parts of ethanol and 75 parts of deionized water, stirred at 1000 r / min for 30 min, and then ultrasonically dispersed at 400 W ultrasonic power and 30℃ for 25 min to obtain a boehmite dispersion; 8.5 parts of bisphenol A type epoxy resin were added to the obtained boehmite dispersion, and stirred at 75℃ and 650 r / min for 3 h. An epoxy-modified boehmite dispersion was obtained. 5.5 parts of polyetheramine were added to the obtained epoxy-modified boehmite dispersion, and the mixture was stirred at 70℃ and 550 r / min for 3.5 h. After the reaction was completed, the mixture was centrifuged at 7000 r / min for 10 min, washed three times with ethanol and deionized water, and vacuum dried at 70℃ and -0.087 MPa for 9 h. The mixture was then ground until the average particle size was 3 μm to obtain epoxy-polyetheramine synergistic modified boehmite.

[0027] S2. Preparation and wet coagulation of polyurethane composite slurry: 125 parts of polyester-type polyurethane resin were added to 115 parts of N,N-dimethylformamide and stirred at 47℃ and 500 r / min for 50 min to dissolve. Then, 13 parts of epoxy-polyetheramine synergistic modified boehmite obtained in step S1, 8 parts of polyethylene glycol, 3 parts of polyvinylpyrrolidone, 0.6 parts of sodium dodecyl sulfate, 3 parts of castor oil, 2.5 parts of fumed silica, and 0.3 parts of silicone defoamer were added sequentially, and the mixture was stirred at 1000 r / min. The mixture was dispersed under vacuum for 40 min and then degassed for 20 min under a vacuum of -0.087 MPa to obtain a polyurethane composite slurry. The obtained polyurethane composite slurry was uniformly coated onto the surface of the base fabric, with the coating thickness controlled at 0.9 mm. The coated base fabric was then immersed in a coagulation bath of N,N-dimethylformamide with a mass concentration of 10% and wet-coagulated at 25 °C for 22.5 min to allow the polyurethane to undergo phase separation and form a uniform porous polyurethane functional layer, thus obtaining the damping fabric blank.

[0028] S3. Post-treatment: The damping fabric blank obtained in step S2 is washed with deionized water at 25°C four times, each time for 7.5 minutes, to remove residual N,N-dimethylformamide and water-soluble components; then it is dried at 115°C for 30 minutes, and the porous polyurethane functional layer is then sanded, sized, and leveled to obtain the high wear-resistant porous damping fabric.

[0029] Example 3: The purpose of this example is to provide a method for preparing highly wear-resistant porous damping fabric under conditions of higher synergistic modified boehmite dosage and higher functional additive dosage, in order to verify the molding stability and wear-resistant enhancement effect of porous polyurethane functional layer under the upper limit of the formulation and process range.

[0030] S1. Preparation of epoxy-polyetheramine synergistic modified boehmite: 100 parts of boehmite were added to a mixed solvent consisting of 200 parts of ethanol and 100 parts of deionized water, stirred at 1100 r / min for 35 min, and then ultrasonically dispersed at 500 W ultrasonic power and 35 °C for 30 min to obtain a boehmite dispersion; 12 parts of bisphenol A type epoxy resin were added to the obtained boehmite dispersion, and stirred at 80 °C and 750 r / min for 3.5 h to obtain an epoxy pre-modified boehmite dispersion; 8 parts of polyetheramine were added to the obtained epoxy pre-modified boehmite dispersion, and stirred at 75 °C and 650 r / min for 4 h. After the reaction was completed, the mixture was centrifuged at 8000 r / min for 12 min, washed three times with ethanol and deionized water, vacuum dried at 75 °C and -0.095 MPa for 10 h, and ground to an average particle size of 5 μm to obtain epoxy-polyetheramine synergistic modified boehmite.

[0031] S2. Preparation and wet coagulation of polyurethane composite slurry: 150 parts of polyester-type polyurethane resin were added to 150 parts of N,N-dimethylformamide and stirred at 55℃ and 600 r / min for 60 min to dissolve. Then, 20 parts of epoxy-polyetheramine synergistic modified boehmite obtained in step S1, 12 parts of polyethylene glycol, 5 parts of polyvinylpyrrolidone, 1.0 part of sodium dodecyl sulfate, 5 parts of castor oil, 4 parts of fumed silica, and 0.5 parts of silicone defoamer were added sequentially, and the mixture was stirred at 1200 r / min. Dispersed under n conditions for 50 min, and degassed under vacuum of -0.095 MPa for 25 min to obtain polyurethane composite slurry; the obtained polyurethane composite slurry was uniformly coated on the surface of the base fabric, and the coating thickness was controlled to be 1.2 mm. The coated base fabric was immersed in an N,N-dimethylformamide-water coagulation bath with a mass concentration of 15% N,N-dimethylformamide, and wet coagulated at 30℃ for 30 min to allow the polyurethane to undergo phase separation and form a porous polyurethane functional layer, thus obtaining the damping fabric blank.

[0032] S3. Post-treatment: The damping cloth blank obtained in step S2 is washed 5 times with deionized water at 30℃ for 10 minutes each time to remove residual N,N-dimethylformamide and water-soluble components; then it is dried at 130℃ for 40 minutes, and then the porous polyurethane functional layer is sanded, fixed in thickness and leveled to obtain high wear-resistant porous damping cloth.

[0033] Comparative Example 1: This comparative example differs from Example 2 in that it uses unmodified boehmite in an equal amount to replace epoxy-polyetheramine synergistically modified boehmite, in order to investigate the effects of unmodified boehmite on the wear resistance, pore structure stability and compression resilience of porous polyurethane functional layers.

[0034] S1. Treatment of boehmite: 100 parts of boehmite were added to a mixed solvent consisting of 160 parts of ethanol and 75 parts of deionized water, stirred at 1000 r / min for 30 min, and then ultrasonically dispersed at 400 W ultrasonic power and 30 °C for 25 min. After dispersion, the mixture was centrifuged at 7000 r / min for 10 min, washed three times with ethanol and deionized water, vacuum dried at 70 °C and -0.087 MPa for 9 h, and ground to an average particle size of 3 μm to obtain unmodified boehmite.

[0035] S2. Preparation and wet coagulation of polyurethane composite slurry: 125 parts of polyester polyurethane resin were added to 115 parts of N,N-dimethylformamide and stirred and dissolved for 50 min at 47℃ and 500 r / min. Then, 13 parts of unmodified boehmite obtained in step S1, 8 parts of polyethylene glycol, 3 parts of polyvinylpyrrolidone, 0.6 parts of sodium dodecyl sulfate, 3 parts of castor oil, 2.5 parts of fumed silica and 0.3 parts of silicone defoamer were added sequentially and dispersed for 40 min at 1000 r / min. Defoaming was then carried out for 20 min under a vacuum of -0.087 MPa to obtain polyurethane composite slurry. The obtained polyurethane composite slurry was uniformly coated on the surface of the base fabric, and the coating thickness was controlled to be 0.9 mm. The coated base fabric was immersed in an N,N-dimethylformamide-water coagulation bath with a mass concentration of 10% N,N-dimethylformamide and wet coagulated at 25℃ for 22.5 min to obtain damping fabric blank.

[0036] S3. Post-treatment: The obtained damping cloth blank is washed with deionized water at 25℃ 4 times, each time for 7.5 min; then dried at 115℃ for 30 min; and then the porous polyurethane functional layer is subjected to sanding, thickness determination and leveling treatment to obtain high wear-resistant porous damping cloth.

[0037] Comparative Example 2: This comparative example differs from Example 2 in that it uses boehmite modified only by bisphenol A type epoxy resin to replace the epoxy-polyetheramine synergistic modification of boehmite in an equal amount, without adding polyetheramine for secondary modification, in order to investigate the effect of polyetheramine participating in synergistic interface modification on the interfacial bonding between boehmite and polyurethane matrix and the overall performance of damping cloth.

[0038] S1. Preparation of epoxy pre-modified boehmite: 100 parts of boehmite were added to a mixed solvent consisting of 160 parts of ethanol and 75 parts of deionized water, stirred at 1000 r / min for 30 min, and then ultrasonically dispersed at 400 W ultrasonic power and 30℃ for 25 min to obtain a boehmite dispersion; 8.5 parts of bisphenol A type epoxy resin were added to the obtained boehmite dispersion, and stirred at 75℃ and 650 r / min for 3 h to obtain an epoxy pre-modified boehmite dispersion; after treatment, the dispersion was centrifuged at 7000 r / min for 10 min, washed three times with ethanol and deionized water, vacuum dried at 70℃ and vacuum degree of -0.087 MPa for 9 h, and ground to an average particle size of 3 μm to obtain epoxy pre-modified boehmite.

[0039] S2. Preparation and wet coagulation of polyurethane composite slurry: 125 parts of polyester polyurethane resin were added to 115 parts of N,N-dimethylformamide and stirred and dissolved for 50 min at 47℃ and 500 r / min. Then, 13 parts of epoxy pre-modified boehmite obtained in step S1, 8 parts of polyethylene glycol, 3 parts of polyvinylpyrrolidone, 0.6 parts of sodium dodecyl sulfate, 3 parts of castor oil, 2.5 parts of fumed silica and 0.3 parts of silicone defoamer were added sequentially and dispersed at 1000 r / min for 40 min. Defoaming was then carried out under a vacuum of -0.087 MPa for 20 min to obtain polyurethane composite slurry. The obtained polyurethane composite slurry was uniformly coated on the surface of the base fabric, and the coating thickness was controlled to be 0.9 mm. The coated base fabric was immersed in an N,N-dimethylformamide-water coagulation bath with a mass concentration of 10% N,N-dimethylformamide and wet coagulated at 25℃ for 22.5 min to obtain damping fabric blank.

[0040] S3. Post-treatment: The obtained damping cloth blank is washed with deionized water at 25℃ 4 times, each time for 7.5 min; then dried at 115℃ for 30 min; and then the porous polyurethane functional layer is sanded, fixed in thickness and leveled to obtain the damping cloth.

[0041] Performance testing: 1. Wear resistance test The damping fabrics prepared in Examples 1-3 and Comparative Examples 1-2 were cut into 100mm × 100mm samples and placed in an environment with a temperature of 23±2℃ and a relative humidity of 50±5% for 24 hours. The abrasion resistance of the porous polyurethane functional layer of the samples was tested using a Taber abrasion tester. The samples were fixed on the test bench, and a CS-10 type grinding wheel was used with a single wheel load of 500g, performing 1000 abrasion cycles at a speed of 60r / min. Before and after the test, the samples were cleaned and dried to constant weight. The mass of the samples was determined using an analytical balance with an accuracy of 0.1mg. The difference in mass before and after the test was taken as the abrasion amount, expressed in mg. Five parallel samples were set up for each group, and the average value was taken. The smaller the abrasion amount, the better the abrasion resistance of the porous polyurethane functional layer of the damping fabric.

[0042] 2. Porosity testing The damping fabrics prepared in Examples 1-3 and Comparative Examples 1-2 were cut into 50mm × 50mm samples and dried to constant weight at 23±2℃. The porosity of the porous polyurethane functional layer was determined using a liquid impregnation method. Anhydrous ethanol was used as the impregnation medium; the samples were completely immersed in anhydrous ethanol and kept under vacuum for 30 minutes to allow the ethanol to fully penetrate the pores of the porous polyurethane functional layer. After removing the samples, residual liquid on the surface was quickly aspirated and the samples were weighed. The porosity was determined based on the mass change of the samples before and after impregnation, the density of anhydrous ethanol, and the apparent volume of the samples. Five parallel samples were tested in each group, and the average value was taken to evaluate the effect of different boehmite interface modification methods on the wet solidification pore-forming process and the ability to retain the porous structure.

[0043] 3. Compression and rebound performance test The damping fabrics prepared in Examples 1-3 and Comparative Examples 1-2 were cut into circular specimens with a diameter of 50 mm and equilibrated for 24 h in an environment of 23±2℃ and 50±5% relative humidity. The compression resilience of the damping fabric was determined using a material compression testing machine. First, the initial thickness of the specimen was measured. Then, a compressive load of 0.5 MPa was applied along the thickness direction and held for 60 s. After unloading, the specimen recovered for 5 min under no-load conditions, and the thickness of the specimen after recovery was measured again. The degree of thickness recovery after unloading was used to evaluate the compression resilience. Five parallel specimens were tested in each group, and the average value was taken. The higher the compression resilience, the stronger the ability of the porous polyurethane functional layer to restore its original structure after compression.

[0044] 4. Tensile strength test The damping fabrics prepared in Examples 1-3 and Comparative Examples 1-2 were cut into strips along the same direction. The strips were 25 mm wide and had an effective clamping length of 100 mm. They were then equilibrated for 24 hours at 23±2℃ and 50±5% relative humidity. Tensile tests were performed using an electronic universal testing machine. The two ends of the strips were fixed in the clamps, and a tensile load was continuously applied at a speed of 100 mm / min until the strips fractured. The maximum tensile load during the fracture process was recorded, and the tensile strength (in MPa) was obtained based on the effective cross-sectional area of ​​the strips. Five parallel strips were tested in each group, and the average value was taken to evaluate the effect of epoxy-polyetheramine synergistic modification of boehmite on the interfacial bonding and overall mechanical stability of the porous polyurethane functional layer.

[0045] Table 1. Test results of high wear-resistant porous damping fabric performance.

[0046] According to Table 1, the high-wear-resistant porous damping fabrics prepared in Examples 1-3 all exhibited good comprehensive performance in terms of wear resistance, porosity, compression resilience, and tensile strength, and were generally superior to those in Comparative Examples 1-2. Among them, Example 2 showed the best comprehensive performance among all samples, with an wear resistance of 17.6 mg, a porosity of 65.7%, a compression resilience of 90.6%, and a tensile strength of 13.8 MPa. This indicates that under suitable raw material ratios and process conditions, epoxy-polyetheramine synergistic modification of boehmite can effectively enhance wear resistance, strengthen interfaces, and stabilize the porous structure. Although the performance of Examples 1 and 3 was slightly lower than that of Example 2, it was still significantly better than the two comparative examples, demonstrating that the raw material ratios and preparation process ranges defined in this invention can all yield porous damping fabrics with good comprehensive performance.

[0047] Regarding wear resistance, the wear amounts of Examples 1-3 were 22.4 mg, 17.6 mg, and 19.8 mg, respectively, significantly lower than 34.5 mg in Comparative Example 1 and 27.9 mg in Comparative Example 2. In particular, Example 2 showed a wear reduction of approximately 49.0% compared to Comparative Example 1, which used unmodified boehmite, indicating that epoxy-polyetheramine synergistic modification can significantly improve the wear resistance of porous polyurethane functional layers. This is because the bisphenol A epoxy resin forms an organic interface layer on the boehmite surface, improving the interfacial bonding between the inorganic boehmite and the polyurethane matrix. Furthermore, the polyetheramine participates in the ring-opening reaction of epoxy groups and forms a flexible polyether interface structure, allowing the boehmite to be more stably dispersed and bonded within the polyurethane pore walls. This reduces particle pull-out, interfacial peeling, and the generation of microcracks in the pore walls during continuous friction, thereby fully utilizing the rigid load-bearing and wear-resistant reinforcing effects of the boehmite.

[0048] Regarding pore structure, the porosities of Examples 1-3 reached 62.8%, 65.7%, and 64.1%, respectively, while those of Comparative Examples 1 and 2 were 56.9% and 59.8%, respectively. Unmodified boehmite exhibited relatively poor interfacial compatibility with the polyurethane system, easily leading to localized particle aggregation. This interfered with the exchange between N,N-dimethylformamide and water and the separation of the polyurethane phase during wet solidification, resulting in the lowest porosity for Comparative Example 1. Comparative Example 2 showed improved porosity after separate modification with bisphenol A epoxy resin, but it remained lower than the examples. This indicates that further introduction of polyetheramine to form a flexible interfacial structure helps improve the dispersion of modified boehmite in the polyurethane slurry, reduces the adverse effects of rigid particle agglomeration on the pore-forming process, and thus facilitates the formation of a more stable porous structure.

[0049] Regarding compression recovery performance, the compression recovery rates of Examples 1-3 ranged from 87.3% to 90.6%, with Example 2 reaching 90.6%, while Comparative Examples 1 and 2 were only 80.8% and 84.2%, respectively. This result indicates that while directly adding unmodified rigid boehmite can provide some reinforcement, it easily causes localized stiffening of the polyurethane pore walls and creates stress concentration regions between the inorganic and polymer phases. After synergistic modification with bisphenol A epoxy resin and polyetheramine, the flexible polyether segments can form a transition interface between the rigid boehmite and the flexible polyurethane. This alleviates localized stress concentration on the pore walls under compressive loads while maintaining the reinforcing effect of the inorganic material, thus reducing irreversible compressive deformation of the porous structure and giving the damping fabric better compression recovery capability.

[0050] Regarding tensile properties, the tensile strengths of Examples 1-3 were 12.3 MPa, 13.8 MPa, and 13.1 MPa, respectively, all significantly higher than 9.6 MPa of Comparative Example 1 and 10.9 MPa of Comparative Example 2. Comparative Example 2 showed a certain degree of performance improvement compared to Comparative Example 1, indicating that the interface treatment of boehmite with bisphenol A epoxy resin can improve its bonding with the polyurethane matrix; however, its performance was still significantly lower than that of the example using epoxy-polyetheramine synergistic modification of boehmite, further demonstrating that the introduction of polyetheramine can improve the organic flexible interface on the surface of boehmite, increase the efficiency of load transfer between the inorganic reinforcing phase and the polyurethane matrix, reduce crack initiation and propagation caused by interface defects, and thus improve the overall mechanical stability of the damping fabric.

[0051] In summary, Comparative Examples 1 and 2, along with Examples 1-3, exhibit a progressive performance relationship from unmodified boehmite, epoxy-modified boehmite alone, to epoxy-polyetheramine synergistic modification of boehmite. This demonstrates that the synergistic interfacial modification of bisphenol A epoxy resin and polyetheramine can effectively improve the dispersion and interfacial bonding of boehmite in the polyurethane system, and mitigate the adverse effects of rigid inorganic materials on the flexibility and pore stability of porous polyurethane. Therefore, this invention can significantly reduce damping cloth wear while simultaneously improving porosity, compression resilience, and tensile strength, achieving a synergistic improvement in wear resistance, pore structure stability, and mechanical properties. The intermediate formulation and process conditions used in Example 2 demonstrate the best overall performance.

Claims

1. A highly wear-resistant porous damping fabric, characterized in that, The product includes a base fabric and a porous polyurethane functional layer formed on the surface of the base fabric. The porous polyurethane functional layer comprises the following raw materials in parts by weight: 100-150 parts of polyester polyurethane resin; 6-20 parts of epoxy-polyetheramine synergistic modified boehmite; 80-150 parts of N,N-dimethylformamide; 4-12 parts of polyethylene glycol; 1-5 parts of polyvinylpyrrolidone; 0.2-1.0 parts of sodium dodecyl sulfate; 1-5 parts of castor oil; 1-4 parts of fumed silica; and 0.1-0.5 parts of silicone defoamer. The epoxy-polyetheramine synergistic modified boehmite is prepared by synergistic modification of boehmite with bisphenol A type epoxy resin and polyetheramine.

2. The high wear-resistant porous damping fabric according to claim 1, characterized in that, The epoxy-polyetheramine synergistic modification of boehmite comprises the following raw materials in parts by weight: 100 parts boehmite; 5-12 parts bisphenol A type epoxy resin; 3-8 parts polyetheramine; 120-200 parts ethanol; and 50-100 parts deionized water.

3. The high wear-resistant porous damping fabric according to claim 1 or 2, characterized in that, The preparation method of the epoxy-polyetheramine synergistic modified boehmite includes the following steps: (1) Boehmite was added to a mixed solvent of ethanol and deionized water, stirred and ultrasonically dispersed to obtain a boehmite dispersion; (2) Add bisphenol A type epoxy resin to the boehmite dispersion and stir to obtain epoxy pre-modified boehmite dispersion. (3) Add polyetheramine to the epoxy premodified boehmite dispersion and stir to react. After the reaction is completed, centrifuge, wash, vacuum dry and grind to obtain epoxy-polyetheramine synergistic modified boehmite.

4. The high wear-resistant porous damping fabric according to claim 3, characterized in that, The reaction conditions for step (1) are: stirring speed of 900-1100 r / min, stirring time of 25-35 min; ultrasonic dispersion power of 300-500 W, ultrasonic dispersion time of 20-30 min, and dispersion temperature of 25-35℃.

5. The high wear-resistant porous damping fabric according to claim 3, characterized in that, The reaction conditions for step (2) are a reaction temperature of 70-80℃, a stirring speed of 550-750r / min, and a reaction time of 2.5-3.5h.

6. The high wear-resistant porous damping fabric according to claim 3, characterized in that, The reaction conditions for step (3) are: reaction temperature of 65-75℃, stirring speed of 450-650 r / min, and reaction time of 3-4 h; after the reaction is completed, centrifuge at 6000-8000 r / min for 8-12 min, wash with ethanol and deionized water 2-3 times in sequence, vacuum dry at 65-75℃ and vacuum degree of -0.08--0.095 MPa for 8-10 h, and grind to an average particle size of 1-5 μm.

7. A method for preparing a highly wear-resistant porous damping fabric, characterized in that, The preparation method includes the following steps: S1, polyester polyurethane resin is added to N,N-dimethylformamide and stirred to dissolve. Then, epoxy-polyetheramine synergistic modified boehmite, polyethylene glycol, polyvinylpyrrolidone, sodium dodecyl sulfate, castor oil, fumed silica and organosilicon defoamer are added in sequence. After stirring, dispersion and vacuum degassing, polyurethane composite slurry is obtained. S2, the obtained polyurethane composite slurry is uniformly coated on the surface of the base fabric, and the coated base fabric is immersed in the coagulation bath for wet coagulation, so that the polyurethane undergoes phase separation and forms a porous polyurethane functional layer to obtain the damping fabric blank. S3. The obtained damping cloth blank is washed and dried, and then the porous polyurethane functional layer is sanded, sized and leveled to obtain a high wear-resistant porous damping cloth.

8. The method for preparing a high wear-resistant porous damping fabric according to claim 7, characterized in that, The reaction conditions for step S1 are as follows: the polyester polyurethane resin is stirred and dissolved at 40-55°C and 400-600 r / min for 40-60 min; after adding the remaining raw materials, it is dispersed at 800-1200 r / min for 30-50 min; after dispersion, it is degassed at a vacuum of -0.08 to -0.095 MPa for 15-25 min.

9. The method for preparing a high wear-resistant porous damping fabric according to claim 7, characterized in that, The reaction conditions for step S2 are as follows: the coating thickness of the polyurethane composite slurry is 0.6-1.2 mm; the coagulation bath is composed of N,N-dimethylformamide and water, wherein the mass concentration of N,N-dimethylformamide is 5-15%, the coagulation bath temperature is 20-30℃, and the wet coagulation time is 15-30 min.

10. The method for preparing a high wear-resistant porous damping fabric according to claim 7, characterized in that, The reaction conditions for step S3 are as follows: washing with deionized water at 20-30℃ 3-5 times, each wash lasting 5-10 minutes; then drying at 100-130℃ for 20-40 minutes; after drying, the porous polyurethane functional layer is subjected to abrasion, thickness determination and leveling treatment.

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