Cold-drawing heat-setting high-elasticity cowhells belt composite material

Abstract

The invention discloses a cold-drawing heat-setting high-elasticity cowhells belt composite material, and relates to the technical field of composite materials. The invention relates to a cold-drawing heat-setting high-elasticity cowhells belt composite material. The composite material is prepared from the following raw materials in parts by weight: 12 to 18 parts of nano calcium carbonate, 0.1 to 0.4 part of silane coupling agent KH-550, 30 to 40 parts of modified thermoplastic polyurethane, 18 to 22 parts of ethylene-vinyl acetate copolymer, 5 to 8 parts of natural rubber, 3 to 5 parts of diisononyl phthalate, 0.3 to 0.5 part of compound antioxidant, 0.2 to 0.4 part of ultraviolet light absorber UV-9, 6 to 8 parts of aramid short fiber and 0.2 to 0.5 part of zinc stearate. 10 to 15 parts of modified polyethylene terephthalate fiber, 0.2 to 0.3 part of graphene and 0.5 to 1.5 parts of organic silicon treatment liquid. According to the cold-drawing heat-setting high-elasticity cowhells belt composite material, a matrix is reinforced through modified thermoplastic polyurethane and modified polyethylene terephthalate fibers, and the strength is improved through aramid short fibers subjected to plasma pretreatment. Molecular orientation is optimized by a cold drawing and heat setting process, weather resistance is enhanced by an organic silicon coating, and good overall elasticity, high strength and excellent wear resistance and weather resistance are achieved.

Description

Technical Field

[0001] This invention relates to the field of composite material technology, specifically to a cold-drawn and heat-set high-elasticity rib-like composite material. Background Technology

[0002] As a highly elastic composite material product, elastic bands are widely used in sports equipment, industrial transmission, and daily necessities. Their performance directly affects the user experience and service life. Traditional elastic bands are mostly made of natural rubber or ordinary thermoplastic elastomers as the base material. Although they have a certain degree of elasticity, they suffer from problems such as insufficient strength, poor aging resistance, and easy deformation at high temperatures.

[0003] In existing technologies, the poor compatibility between the matrix material and the reinforcing fibers often leads to uneven fiber dispersion, preventing the reinforcing effect from being fully realized and hindering the improvement of tensile strength and tear resistance. Furthermore, ordinary reinforcing tape is susceptible to aging phenomena such as elasticity loss and surface cracking under long-term use, especially in high-temperature or outdoor environments where performance degradation is accelerated.

[0004] Furthermore, in traditional manufacturing processes, localized degradation of raw materials is prone to occur during the mixing process, and uneven molecular chain orientation occurs during cold drawing and shaping, resulting in low elastic recovery and poor dimensional stability of the product. The silicone coating also does not bond firmly to the substrate, easily peeling off and affecting wear resistance and high / low temperature resistance.

[0005] As application scenarios demand higher performance from reinforcing steel strips, traditional products can no longer meet the requirements for high elasticity, high strength, and strong weather resistance. There is an urgent need to develop new reinforcing steel strip composite materials that combine excellent mechanical properties and environmental adaptability through material modification, process optimization, and other means. Summary of the Invention

[0006] To address the shortcomings of existing technologies, this invention provides a cold-drawn and heat-set high-elasticity reinforcing strip composite material, which solves the problems of poor compatibility, rapid aging, and low stability of traditional materials.

[0007] To achieve the above objectives, the present invention provides the following technical solution:

[0008] A cold-drawn and heat-set high-elasticity elastic band composite material comprises the following raw materials in parts by weight: 12-18 parts nano-calcium carbonate, 0.1-0.4 parts silane coupling agent KH-550, 30-40 parts modified thermoplastic polyurethane, 18-22 parts ethylene-vinyl acetate copolymer, 5-8 parts natural rubber, 3-5 parts diisononyl phthalate, 0.3-0.5 parts compound antioxidant, 0.2-0.4 parts ultraviolet absorber UV-9, 6-8 parts aramid short fiber, 0.2-0.5 parts zinc stearate, 10-15 parts modified polyethylene terephthalate fiber, 0.2-0.3 parts graphene, and 0.5-1.5 parts organosilicon treatment liquid.

[0009] Furthermore, the compound antioxidant is a mixture of antioxidant 1010 and antioxidant 168 in a 1:1 mass ratio, and their synergistic effect can effectively inhibit the oxidative degradation of the material; the organosilicon treatment liquid contains 60-75wt% vinyl-terminated polydimethylsiloxane, 5-10wt% hydrogen-containing silicone oil crosslinking agent, 0.1-0.5wt% platinum catalyst, and 20-35wt% xylene solvent, which can form a strong protective film on the material surface to enhance weather resistance and wear resistance.

[0010] Furthermore, the natural rubber is an epoxidized natural rubber with an epoxidation degree of 25-30%. The modification method is as follows: dissolve the natural rubber in toluene, add a mixture of formic acid and hydrogen peroxide in a mass ratio of 1:1, react at 50°C for 2 hours, and then wash and dry to obtain the product. Epoxidation modification can improve the compatibility and aging resistance of natural rubber with the matrix.

[0011] Furthermore, the aramid short fibers are pretreated with plasma under the following conditions: oxygen atmosphere, power 300W, treatment time 60s. After treatment, hydroxyl and carboxyl groups are introduced onto the fiber surface to enhance the interfacial bonding force with the matrix. The pretreated aramid short fibers have a length of 3-5mm and a diameter of 12-15μm, which can fully exert the reinforcing effect to improve the tensile strength and tear resistance of the material.

[0012] Furthermore, the modified thermoplastic polyurethane is prepared using the following specific steps:

[0013] A1. In a four-necked flask, thermoplastic polyurethane particles, xylene, maleic anhydride, N,N-dimethylacrylamide, dicumyl peroxide, and benzoyl peroxide were added sequentially. The mixture was stirred at 300 rpm and heated to 85°C for 3 hours. After the reaction, the temperature was lowered to 60°C and maintained for 30 minutes, then lowered to 25°C and maintained for 30 minutes. The reaction solution was transferred to a beaker containing ethyl acetate and stirred at 200 rpm for 30 minutes in an ice-water bath. Triethanolamine was added dropwise, and the reaction continued for 50 minutes. The reaction solution was transferred to a separatory funnel, washed three times with 5% dilute sulfuric acid solution, and then washed with deionized water until neutral. Anhydrous magnesium sulfate was added and the mixture was dried for 10 hours. After filtration, the filtrate was rotary evaporated at 60°C and -0.08 MPa to remove the solvent, yielding a primary modified thermoplastic polyurethane. Grafting modification was used to introduce active groups to improve reactivity and compatibility.

[0014] A2. γ-glycidyl etheroxypropyltrimethoxysilane was pre-adjusted to pH 4 with 0.1M acetic acid and hydrolyzed for 30 min. Primary modified thermoplastic polyurethane and ethanol were added to a reaction vessel, and the mixture was stirred at 250 r / min for 60 min to disperse it. Then, hydrolyzed silane solution, stannous octoate, and sulfamic acid were added. The mixture was reacted at 75℃ for 2 h, then heated to 85℃ for another 2 h to further optimize the molecular structure and enhance the interfacial bonding with other components. After the reaction, the solvent was removed by rotary evaporation at 70℃ and -0.09 MPa. The remaining solid was washed three times with ethanol and dried at 60℃ for 4 h to obtain secondary modified thermoplastic polyurethane.

[0015] A3. Nano zinc oxide and vinyltrimethoxysilane were vapor-treated in a reactor at 120°C for 2 hours to graft silane groups onto their surfaces. The secondary modified thermoplastic polyurethane and the pretreated nano zinc oxide were added to a high-speed mixer and mixed at 1000 r / min for 15 min to ensure uniform initial dispersion. The introduction of nano zinc oxide can enhance the material's UV resistance and mechanical strength. The mixture was fed into a twin-screw extruder with the following temperatures set: 190°C in the melting zone, 215°C in the high-shear dispersion zone, and 210°C in the homogenization zone. The screw speed was set to 150 r / min in the shear zone and 250 r / min in the other zones. After melt extrusion, the material was cooled in water at 25°C and then pelletized by a pelletizer to obtain the final modified thermoplastic polyurethane particles.

[0016] Furthermore, the ratio of thermoplastic polyurethane particles, xylene, maleic anhydride, N,N-dimethylacrylamide, dicumyl peroxide, benzoyl peroxide, ethyl acetate, triethanolamine, and anhydrous magnesium sulfate in A1 is 100g:150mL:12g:2g:0.8g:0.2g:200mL:10g:20g;

[0017] Furthermore, the ratio of the amount of the one-time modified thermoplastic polyurethane, ethanol, hydrolyzed silane solution, stannous octoate, and aminosulfonic acid in A2 is 100g:300mL:10g:0.3g:0.2g;

[0018] Furthermore, in A3, the ratio of nano zinc oxide to vinyltrimethoxysilane is 3g:0.75g; and the ratio of secondary modified thermoplastic polyurethane to pretreated nano zinc oxide is 100g:3g.

[0019] Furthermore, the modified polyethylene terephthalate fiber is prepared using the following specific steps:

[0020] B1. Add deionized water, sodium hydroxide, and potassium hydroxide to the reaction vessel and stir until completely dissolved. Immerse the polyethylene terephthalate fiber in the solution and stir at 150 r / min for 30 min at 65℃. The alkali treatment removes surface impurities and introduces active sites. After the treatment, remove the fiber with tweezers and rinse with deionized water until the pH of the rinsing solution is 7. Immerse the fiber in 1% polyethyleneimine solution for 20 min, and then dry it at 100℃ for 1.5 h to obtain the first-modified polyethylene terephthalate fiber.

[0021] B2. Prepare a silane hydrolysate by mixing ethanol, water, and 3-glycidyl etheroxypropyltrimethoxysilane in a mass ratio of 85:10:5 and adjusting the pH to 5.5. Add the primary modified polyethylene terephthalate fiber to the silane hydrolysate and ultrasonically disperse it at 150W for 10 min. Then add cerium ammonium nitrate and stir at 180 r / min at 60℃ for 2 h. After the reaction is complete, remove the fiber, rinse it twice with ethanol, and then dry it in an oven at 80℃ for 3 h to obtain the secondary modified polyethylene terephthalate fiber. Silane modification significantly improves the compatibility between the fiber and the matrix.

[0022] B3. Toluene, dimethyl sulfoxide, and secondary modified polyethylene terephthalate (PET) fibers were added to the reactor. Nitrogen gas was introduced to replace the air in the container for 15 minutes, and the nitrogen atmosphere was maintained. Isocyanate methacrylate was added, and the temperature was raised to 75°C. The mixture was stirred at 200 r / min for 2 hours. The isocyanate grafting further enhanced the interfacial bonding between the fiber and the matrix, improving the overall integrity of the composite material. After the reaction was completed, acetone was added to terminate the reaction. The fibers were collected by filtering with a filter screen and washed twice with acetone. The washed fibers were transferred to a vacuum oven and dried at 70°C for 5 hours to obtain the final modified PET fibers.

[0023] Furthermore, the ratio of deionized water, sodium hydroxide and potassium hydroxide, polyethylene terephthalate fiber, and polyethyleneimine solution in B1 is 500g:30g:10g:100g:300g.

[0024] Furthermore, the ratio of the amount of the one-time modified polyethylene terephthalate fiber, the silane hydrolysate, and the cerium ammonium nitrate in B2 is 100g:200g:0.05g;

[0025] Furthermore, the ratio of toluene, dimethyl sulfoxide, secondary modified polyethylene terephthalate fiber, isocyanate methacrylate, and acetone in B3 is 120mL:30mL:100g:5g:100mL.

[0026] A method for preparing a cold-drawn and heat-set high-elasticity reinforcing strip composite material, specifically comprising the following steps:

[0027] S1. Nano-calcium carbonate and silane coupling agent KH-550 are mixed at high speed at 100℃ for 10 min to obtain pretreated nano-calcium carbonate, which improves the dispersibility and compatibility of nano-calcium carbonate in the matrix. Modified thermoplastic polyurethane, ethylene-vinyl acetate copolymer, and natural rubber are added to a mixer and mixed at 120℃ and 60 r / min for 5 min. The temperature is then raised to 140℃, and nitrogen protection is introduced for continued mixing for 20 min to obtain a preliminary mixture. Pretreated nano-calcium carbonate, diisononyl phthalate, compound antioxidant, UV absorber UV-9, and aramid short fibers are added to the mixer at preheated to 80℃. Zinc stearate is added, and the mixture is mixed at 80 r / min for 10 min to obtain a compound. Segmented mixing avoids local degradation of raw materials and ensures uniform mixing of components.

[0028] S2. The mixture is fed into a twin-screw extruder, with the following temperature settings: Zone 1 175-185℃, Zone 2 185-195℃, Zone 3 195-205℃, screw speed 220-250 r / min, and melt pressure 10 MPa. Simultaneously, modified polyethylene terephthalate fiber and graphene are fed into the extruder, thoroughly mixed, and then extruded. The gradient temperature setting matches the melting characteristics of the materials to ensure thorough mixing and prevent thermal degradation.

[0029] S3. After extrusion molding, the material is stretched using a multi-stage cold drawing device. Specifically: the first stage stretching ratio is 1.2-1.5 times, and the stretching rate is 50 mm / min; the second stage stretching ratio is 1.8-2.0 times, and the stretching rate is 80 mm / min; the two stages of stretching are held for 1 minute, and infrared heating is used to locally preheat the surface of the elastic band during the stretching process, with a preheating temperature of 40-50℃. Multi-stage cold drawing optimizes the molecular chain orientation and improves elasticity and strength. After cold drawing, the elastic band is heat-set by hot air circulation: held at 155℃ for 4 minutes, and then heated to 170℃ for 1 minute. Heat setting stabilizes the molecular structure and reduces internal stress rebound. Then, an 8-10 μm thick silicone coating is applied using a roller coating process. After coating, it is cured in a 120℃ oven for 30 minutes. The silicone coating enhances the material's weather resistance, wear resistance, and high and low temperature resistance, resulting in a cold-drawn and heat-set high-elasticity elastic band composite material.

[0030] This invention provides a cold-drawn and heat-set high-elasticity reinforcing strip composite material, which has the following beneficial effects:

[0031] 1. By pretreating aramid short fibers with oxygen plasma to introduce hydroxyl and carboxyl active groups, and simultaneously using epoxidation to modify natural rubber and prepare modified thermoplastic polyurethane, the compatibility of the fibers, rubber, and thermoplastic polyurethane matrix is ​​significantly improved. The modified components are uniformly dispersed, avoiding agglomeration. The high strength characteristics of the aramid fibers and the elastic advantages of the matrix work synergistically, resulting in a significant improvement in the tensile strength, tear resistance, and elastic recovery rate of the composite material compared to traditional materials. This solves the problem of insufficient mechanical properties caused by weak interfacial bonding in traditional reinforcing strips.

[0032] 2. The compound antioxidants in the product effectively inhibit the oxidative degradation of materials. The UV-9 ultraviolet absorber, encapsulated in organosilicon microcapsules, delays migration and volatilization, extending the UV aging resistance period. Simultaneously, the organosilicon treatment solution coating forms a robust protective film on the substrate surface after corona treatment. Combined with the nano-zinc oxide UV-resistant component in the modified thermoplastic polyurethane, this creates a multi-barrier protection system that resists oxidation, UV rays, and high and low temperatures, solving the aging problems of elasticity loss and surface cracking that occur with traditional elastic bands during long-term use.

[0033] 3. Nano-calcium carbonate is pretreated with silane coupling agent KH-550, and graphene is modified with silane coupling agent KH-560. The mixture is then mixed in stages at controlled temperature using an internal mixer to achieve uniform dispersion of the fillers in the matrix. The modified nanoparticles form chemical bonds with the matrix. Nano-calcium carbonate enhances rigidity, and graphene improves thermal conductivity. Together with aramid fibers and modified polyester fibers, they form a multi-dimensional reinforcing network, enabling the composite material to maintain high elasticity while also possessing excellent wear resistance, oil resistance, and thermal conductivity stability. This overcomes the limitations of traditional reinforced fiber reinforced belts, which excel in a single property but lack comprehensive performance.

[0034] 4. A multi-stage cold-drawing gradient stretching process is adopted, with step-by-step control of the stretching ratio and rate. Combined with infrared local preheating and hot air circulation gradient heat setting, this promotes uniform orientation and stable arrangement of the molecular chains within the material. Slight tension cooling after cold drawing further reduces internal stress rebound. Then, the composite material is fed in layers through a twin-screw extruder, ensuring stable dimensional accuracy even after repeated stretching. This solves the problems of shrinkage deformation and low elastic recovery accuracy caused by uneven orientation in traditional processes. Detailed Implementation

[0035] The technical solutions in the embodiments of the present invention will be clearly and completely described below. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0036] Example 1: Preparation of cold-drawn and heat-set high-elasticity rib-like composite material. The specific preparation steps are as follows:

[0037] S1. Mix 12 parts of nano-calcium carbonate with 0.1 parts of silane coupling agent KH-550 at 100℃ for 10 min to obtain pretreated nano-calcium carbonate; add 30 parts of modified thermoplastic polyurethane, 18 parts of ethylene-vinyl acetate copolymer, and 5 parts of natural rubber to a mixer and mix at 120℃ and 60 r / min for 5 min, then raise the temperature to 140℃, and continue mixing under nitrogen protection for 20 min to obtain a preliminary mixture; then add 12 parts of pretreated nano-calcium carbonate preheated to 80℃, 3 parts of diisononyl phthalate, 0.3 parts of compound antioxidant, 0.2 parts of ultraviolet absorber UV-9, and 6 parts of aramid short fiber to the mixer, add 0.2 parts of zinc stearate, and mix at 80 r / min for 10 min to obtain a mixture.

[0038] S2. The mixture is fed into a twin-screw extruder, and the temperature is set as follows: Zone 1 175℃, Zone 2 185℃, Zone 3 195℃, screw speed 220r / min, melt pressure 10MPa; at the same time, 10 parts of modified polyethylene terephthalate fiber and 0.2 parts of graphene are fed into the extruder, mixed thoroughly, and then extruded.

[0039] S3. After extrusion molding, the material is stretched using a multi-stage cold drawing device. Specifically, the first stage stretching ratio is 1.2 times, and the stretching rate is 50 mm / min; the second stage stretching ratio is 1.8 times, and the stretching rate is 80 mm / min. The two stages of stretching are held for 1 minute, and infrared heating is used to locally preheat the surface of the elastic strip during the stretching process at a preheating temperature of 40℃. After cold drawing, the elastic strip is heat-set by hot air circulation: held at 155℃ for 4 minutes, and then heated to 170℃ for 1 minute. Then, an 8μm thick silicone treatment liquid coating is applied using a roller coating process. After coating, it is cured in an oven at 120℃ for 30 minutes to obtain a cold-drawn and heat-set high-elasticity elastic strip composite material.

[0040] Example 2: Preparation of cold-drawn and heat-set high-elasticity rib-like composite material. The specific preparation steps are as follows:

[0041] S1. Mix 18 parts of nano-calcium carbonate with 0.4 parts of silane coupling agent KH-550 at 100℃ for 10 min to obtain pretreated nano-calcium carbonate; add 40 parts of modified thermoplastic polyurethane, 22 parts of ethylene-vinyl acetate copolymer, and 8 parts of natural rubber to a mixer and mix at 120℃ and 60 r / min for 5 min, then raise the temperature to 140℃, and continue mixing under nitrogen protection for 20 min to obtain a preliminary mixture; then add 18 parts of pretreated nano-calcium carbonate preheated to 80℃, 5 parts of diisononyl phthalate, 0.5 parts of compound antioxidant, 0.4 parts of ultraviolet absorber UV-9, and 8 parts of aramid short fiber to the mixer, add 0.5 parts of zinc stearate, and mix at 80 r / min for 10 min to obtain a mixture.

[0042] S2. The mixture is fed into a twin-screw extruder, and the temperature is set as follows: Zone 1 185℃, Zone 2 195℃, Zone 3 205℃, screw speed 250r / min, melt pressure 10MPa; at the same time, 15 parts of modified polyethylene terephthalate fiber and 0.3 parts of graphene are fed into the extruder, mixed thoroughly, and then extruded.

[0043] S3. After extrusion molding, the material is stretched using a multi-stage cold drawing device. Specifically, the first stage stretching ratio is 1.5 times, and the stretching rate is 50 mm / min; the second stage stretching ratio is 2.0 times, and the stretching rate is 80 mm / min; the two stages of stretching are held for 1 minute apart, and infrared heating is used to locally preheat the surface of the elastic strip during the stretching process, with a preheating temperature of 50℃; after cold drawing, the elastic strip is heat-set by hot air circulation: held at 155℃ for 4 minutes, and then heated to 170℃ for 1 minute; then a 10 μm thick silicone treatment liquid coating is applied using a roller coating process, and after coating, it is cured in an oven at 120℃ for 30 minutes to obtain a cold-drawn and heat-set high-elasticity elastic strip composite material.

[0044] Example 3: Preparation of cold-drawn and heat-set high-elasticity rib-like composite material. The specific preparation steps are as follows:

[0045] S1. Mix 15 parts of nano-calcium carbonate with 0.3 parts of silane coupling agent KH-550 at 100℃ for 10 min to obtain pretreated nano-calcium carbonate; add 35 parts of modified thermoplastic polyurethane, 20 parts of ethylene-vinyl acetate copolymer, and 6 parts of natural rubber to a mixer and mix at 120℃ and 60 r / min for 5 min, then raise the temperature to 140℃, and continue mixing under nitrogen protection for 20 min to obtain a preliminary mixture; then add 15 parts of pretreated nano-calcium carbonate preheated to 80℃, 4 parts of diisononyl phthalate, 0.4 parts of compound antioxidant, 0.3 parts of ultraviolet absorber UV-9, and 7 parts of aramid short fiber to the mixer, add 0.3 parts of zinc stearate, and mix at 80 r / min for 10 min to obtain a mixture.

[0046] S2. The mixture is fed into a twin-screw extruder, and the temperature is set as follows: Zone 1 180℃, Zone 2 190℃, Zone 3 200℃, screw speed 235r / min, melt pressure 10MPa; at the same time, 12 parts of modified polyethylene terephthalate fiber and 0.2 parts of graphene are fed into the extruder, mixed thoroughly, and then extruded.

[0047] S3. After extrusion molding, the material is stretched using a multi-stage cold drawing device. Specifically, the first stage stretching ratio is 1.3 times and the stretching rate is 50 mm / min; the second stage stretching ratio is 1.9 times and the stretching rate is 80 mm / min. The two stages of stretching are held for 1 minute, and infrared heating is used to locally preheat the surface of the elastic strip during the stretching process at a preheating temperature of 45℃. After cold drawing, the elastic strip is heat-set by hot air circulation: held at 155℃ for 4 minutes, and then heated to 170℃ for 1 minute. Then, a 9μm thick silicone treatment liquid coating is applied using a roller coating process. After coating, it is cured in an oven at 120℃ for 30 minutes to obtain a cold-drawn and heat-set high-elasticity elastic strip composite material.

[0048] Example 4: Preparation of modified thermoplastic polyurethane. The specific preparation steps are as follows:

[0049] A1. Add 100g of thermoplastic polyurethane granules, 150mL of xylene, 12g of maleic anhydride, 2g of N,N-dimethylacrylamide, 0.8g of dicumyl peroxide, and 0.2g of benzoyl peroxide to a four-necked flask in sequence. Stir at 300r / min and heat to 85℃ for 3h. After the reaction is complete, first lower the temperature to 60℃ and maintain for 30min, then lower the temperature to 25℃ and maintain for 30min. Transfer the reaction solution to a beaker containing 200mL of ethyl acetate and stir at 200r / min for 30min in an ice-water bath. Add 10g of triethanolamine dropwise and continue the reaction for 50min. Transfer the reaction solution to a separatory funnel, wash three times with 5% dilute sulfuric acid solution, then wash with deionized water until neutral. Add 20g of anhydrous magnesium sulfate and dry for 10h. After filtration, remove the solvent by rotary evaporation at 60℃ and -0.08MPa to obtain primary modified thermoplastic polyurethane.

[0050] A2. 10g of γ-glycidyl etheroxypropyltrimethoxysilane was pre-adjusted to pH 4 with 0.1M acetic acid and hydrolyzed for 30 min. 100g of primary modified thermoplastic polyurethane and 300mL of ethanol were added to a reaction vessel and stirred at 250r / min for 60 min to disperse the mixture. Then, the hydrolyzed silane solution, 0.3g of stannous octoate and 0.2g of aminosulfonic acid were added. The mixture was reacted at 75℃ for 2 h, then heated to 85℃ and reacted for another 2 h. After the reaction was completed, the solvent was removed by rotary evaporation at 70℃ and -0.09MPa. The remaining solid was washed three times with ethanol and dried at 60℃ for 4 h to obtain secondary modified thermoplastic polyurethane.

[0051] A3. 3g of nano zinc oxide and 0.75g of vinyltrimethoxysilane were vapor-treated in a reactor at 120℃ for 2h to graft silane groups onto their surfaces. 100g of secondary modified thermoplastic polyurethane and the pretreated 3g of nano zinc oxide were added to a high-speed mixer and mixed at 1000r / min for 15min to ensure initial uniform dispersion. The mixture was then fed into a twin-screw extruder with the following temperatures set: melting zone 190℃, high shear dispersion zone 215℃, and homogenization zone 210℃. The screw speed was set to 150r / min in the shear zone and 250r / min in other zones. After melt extrusion, the material was water-cooled at 25℃ and then pelletized by a pelletizer to obtain the final modified thermoplastic polyurethane particles.

[0052] Example 5: Preparation of modified polyethylene terephthalate fiber. The specific preparation steps are as follows:

[0053] B1. Add 500g of deionized water, 30g of sodium hydroxide and 10g of potassium hydroxide to the reaction vessel and stir until completely dissolved. Immerse 100g of polyethylene terephthalate fiber in the solution and stir at 150r / min at 65℃ for 30min. After the stirring is complete, remove the fiber with tweezers and rinse with deionized water until the pH of the rinsing solution is 7. Immerse the fiber in 300g of 1% polyethyleneimine solution for 20min. After removing it, dry it at 100℃ for 1.5h to obtain primary modified polyethylene terephthalate fiber.

[0054] B2. Prepare 200g of silane hydrolysate by mixing ethanol, water, and 3-glycidoxypropyltrimethoxysilane in a mass ratio of 85:10:5 and adjusting the pH to 5.5. Add 100g of primary modified polyethylene terephthalate fiber to the silane hydrolysate and ultrasonically disperse it at 150W for 10min. Then add 0.05g of cerium ammonium nitrate and stir at 180r / min at 60℃ for 2h. After the reaction is complete, take out the fiber, wash it twice with ethanol, and then dry it in an oven at 80℃ for 3h to obtain secondary modified polyethylene terephthalate fiber.

[0055] B3. Add 120 mL of toluene, 30 mL of dimethyl sulfoxide, and 100 g of secondary modified polyethylene terephthalate fiber to the reaction vessel. Purge with nitrogen to replace the air in the container for 15 min, maintain the nitrogen atmosphere, add 5 g of isocyanate methacrylate, heat to 75 °C, and stir at 200 r / min for 2 h. After the reaction is complete, add 100 mL of acetone to terminate the reaction. Filter the fiber using a filter screen, wash it twice with acetone, transfer the washed fiber to a vacuum oven, and dry it at 70 °C for 5 h to obtain the final modified polyethylene terephthalate fiber.

[0056] Comparative Example 1: A cold-drawn and heat-set high-elasticity reinforcing strip composite material was prepared. The specific preparation steps are as follows:

[0057] The remaining steps remain unchanged, except that the modified thermoplastic polyurethane in Example 3 is replaced with untreated thermoplastic polyurethane to prepare a cold-drawn and heat-set high-elasticity rib-stretcher composite material.

[0058] Comparative Example 2: A cold-drawn and heat-set high-elasticity rib-like composite material was prepared. The specific preparation steps are as follows:

[0059] The remaining steps remain unchanged, except that the modified polyethylene terephthalate fiber in Example 3 is replaced with untreated polyethylene terephthalate fiber to prepare a cold-stretched and heat-set high-elasticity ribbed composite material.

[0060] Performance testing

[0061] Test Project Test Standards Example 1 Example 2 Example 3 Comparative Example 1 Comparative Example 2 Tensile strength (MPa) GB / T 1040.3-2006 28.5 30.1 31.2 22.3 24.8 Elongation at break (%) GB / T 1040.3-2006 480 500 520 350 380 Elastic recovery rate (%) GB / T 528-2009 89 90 91 72 75 Aging resistance (tensile strength retention rate, %) GB / T 14522-2008 88 89 90 65 68 Abrasion resistance (wear loss, mg / 1000 rpm) GB / T 1689-2014 0.18 0.17 0.16 0.32 0.28 Heat distortion temperature (0.45 MPa, °C) GB / T 1634.2-2019 85 85 86 80 81

[0062] According to the performance test results, the cold-drawn and heat-set high-elasticity reinforcing strip composite materials of Examples 1-3 are superior to those of Comparative Examples 1-2 in all aspects. Among them, Example 3 has the best overall performance, with a tensile strength of 31.2 MPa, an elongation at break of 520%, an elastic recovery rate of 91%, a tensile strength retention rate under aging of 90%, an abrasion loss of only 0.16 mg, and a heat distortion temperature of 86℃. In contrast, the comparative examples using unmodified thermoplastic polyurethane or unmodified polyethylene terephthalate fiber show significant decreases in tensile strength, elastic recovery rate, aging resistance, and abrasion resistance, indicating that material modification plays a key role in improving the overall performance of the composite material.

[0063] The above description is merely an example and illustration of the present invention. Those skilled in the art can make various modifications or additions to the specific embodiments described, or use similar methods to replace them, as long as they do not deviate from the invention or exceed the scope defined in the claims, all of which should fall within the protection scope of the present invention.

Claims

1. A cold-drawn and heat-set high-elasticity reinforcing strip composite material, characterized in that: It contains the following raw materials in parts by weight: 12-18 parts nano calcium carbonate, 0.1-0.4 parts silane coupling agent KH-550, 30-40 parts modified thermoplastic polyurethane, 18-22 parts ethylene-vinyl acetate copolymer, 5-8 parts natural rubber, 3-5 parts diisononyl phthalate, 0.3-0.5 parts compound antioxidant, 0.2-0.4 parts ultraviolet absorber UV-9, 6-8 parts aramid staple fiber, 0.2-0.5 parts zinc stearate, 10-15 parts modified polyethylene terephthalate fiber, 0.2-0.3 parts graphene, and 0.5-1.5 parts organosilicon treatment solution.

2. The cold-drawn and heat-set high-elasticity reinforcing strip composite material according to claim 1, characterized in that: The compound antioxidant is antioxidant 1010 and antioxidant 168 compounded in a mass ratio of 1:1; the organosilicon treatment liquid contains 60-75wt% vinyl-terminated polydimethylsiloxane, 5-10wt% hydrogen-containing silicone oil crosslinking agent, 0.1-0.5wt% platinum catalyst, and 20-35wt% xylene solvent.

3. The cold-drawn and heat-set high-elasticity reinforcing strip composite material according to claim 1, characterized in that: The natural rubber is an epoxidized natural rubber with an epoxidation degree of 25-30%. The modification method is as follows: dissolve the natural rubber in toluene, add a mixture of formic acid and hydrogen peroxide in a mass ratio of 1:1, react at 50°C for 2 hours, and then wash and dry to obtain the product.

4. The cold-drawn and heat-set high-elasticity reinforcing strip composite material according to claim 1, characterized in that: The aramid short fibers were pretreated with plasma under the following conditions: oxygen atmosphere, power 300W, treatment time 60s. The pretreated aramid short fibers have a length of 3-5 mm and a diameter of 12-15 μm.

5. The cold-drawn and heat-set high-elasticity reinforcing strip composite material according to claim 1, characterized in that: The modified thermoplastic polyurethane is prepared using the following specific steps: A1. Add thermoplastic polyurethane particles, xylene, maleic anhydride, N,N-dimethylacrylamide, dicumyl peroxide, and benzoyl peroxide sequentially to a four-necked flask. Stir at 300 rpm and heat to 85°C for 3 hours. After the reaction, lower the temperature to 60°C and maintain for 30 minutes, then lower it to 25°C and maintain for 30 minutes. Transfer the reaction solution to a beaker containing ethyl acetate and stir at 200 rpm for 30 minutes in an ice-water bath. Add triethanolamine dropwise and continue the reaction for 50 minutes. Transfer the reaction solution to a separatory funnel, wash three times with 5% dilute sulfuric acid solution, then wash with deionized water until neutral. Add anhydrous magnesium sulfate and dry for 10 hours. Filter the solution and remove the solvent by rotary evaporation at 60°C and -0.08 MPa to obtain a primary modified thermoplastic polyurethane. A2. γ-glycidyl etheroxypropyltrimethoxysilane was pre-adjusted to pH 4 with 0.1M acetic acid and hydrolyzed for 30 min. Primary modified thermoplastic polyurethane and ethanol were added to a reaction vessel, and the mixture was stirred at 250 r / min for 60 min to disperse it. Then, hydrolyzed silane solution, stannous octoate, and aminosulfonic acid were added. The mixture was reacted at 75℃ for 2 h, then heated to 85℃ and reacted for another 2 h. After the reaction was complete, the solvent was removed by rotary evaporation at 70℃ and -0.09 MPa. The remaining solid was washed three times with ethanol and dried at 60℃ for 4 h to obtain secondary modified thermoplastic polyurethane. A3. Nano zinc oxide and vinyltrimethoxysilane were vapor-treated in a reactor at 120°C for 2 hours to graft silane groups onto their surfaces. The secondary modified thermoplastic polyurethane and the pretreated nano zinc oxide were added to a high-speed mixer and mixed at 1000 r / min for 15 min to ensure initial uniform dispersion. The mixture was then fed into a twin-screw extruder with the following temperatures set: melting zone 190°C, high shear dispersion zone 215°C, and homogenization zone 210°C. The screw speed was set to 150 r / min in the shear zone and 250 r / min in other zones. After melt extrusion, the material was cooled in water at 25°C and then pelletized by a pelletizer to obtain the final modified thermoplastic polyurethane particles.

6. The cold-drawn and heat-set high-elasticity reinforcing strip composite material according to claim 5, characterized in that: The ratio of thermoplastic polyurethane particles, xylene, maleic anhydride, N,N-dimethylacrylamide, dicumyl peroxide, benzoyl peroxide, ethyl acetate, triethanolamine, and anhydrous magnesium sulfate in A1 is 100g:150mL:12g:2g:0.8g:0.2g:200mL:10g:20g; The ratio of the amount of the modified thermoplastic polyurethane, ethanol, hydrolyzed silane solution, stannous octoate, and aminosulfonic acid in A2 is 100g:300mL:10g:0.3g:0.2g. The ratio of nano zinc oxide to vinyltrimethoxysilane in A3 is 3g:0.75g; the ratio of secondary modified thermoplastic polyurethane to pretreated nano zinc oxide is 100g:3g.

7. The cold-drawn and heat-set high-elasticity reinforcing strip composite material according to claim 1, characterized in that: The modified polyethylene terephthalate fiber is prepared using the following specific steps: B1. Add deionized water, sodium hydroxide and potassium hydroxide to the reaction vessel and stir until completely dissolved. Immerse the polyethylene terephthalate fiber in the solution and stir at 150 r / min at 65℃ for 30 min. After the stirring is complete, remove the fiber with tweezers and rinse with deionized water until the pH of the rinsing solution is 7. Immerse the fiber in 1% polyethyleneimine solution for 20 min, and then dry it at 100℃ for 1.5 h to obtain the one-time modified polyethylene terephthalate fiber. B2. Prepare a silane hydrolysate by mixing ethanol, water, and 3-glycidyl etheroxypropyltrimethoxysilane in a mass ratio of 85:10:5 and adjusting the pH to 5.

5. Add the primary modified polyethylene terephthalate fiber to the silane hydrolysate and ultrasonically disperse it at 150W for 10 min. Then add cerium ammonium nitrate and stir at 180 r / min at 60℃ for 2 h. After the reaction is complete, take out the fiber, wash it twice with ethanol, and then dry it in an oven at 80℃ for 3 h to obtain the secondary modified polyethylene terephthalate fiber. B3. Add toluene, dimethyl sulfoxide, and secondary modified polyethylene terephthalate fiber to the reaction vessel. Purge with nitrogen to replace the air in the container for 15 minutes, maintaining the nitrogen atmosphere. Add isocyanate methacrylate, heat to 75°C, and stir at 200 r / min for 2 hours. After the reaction is complete, add acetone to terminate the reaction. Filter the fiber using a filter screen, wash it twice with acetone, and transfer the washed fiber to a vacuum oven to dry at 70°C for 5 hours to obtain the final modified polyethylene terephthalate fiber.

8. The cold-drawn and heat-set high-elasticity reinforcing strip composite material according to claim 7, characterized in that: The ratio of deionized water, sodium hydroxide and potassium hydroxide, polyethylene terephthalate fiber, and polyethyleneimine solution in B1 is 500g:30g:10g:100g:300g. The ratio of the amount of the one-time modified polyethylene terephthalate fiber, silane hydrolysate, and cerium ammonium nitrate in B2 is 100g:200g:0.05g; The ratio of toluene, dimethyl sulfoxide, secondary modified polyethylene terephthalate fiber, isocyanate methacrylate, and acetone in B3 is 120mL:30mL:100g:5g:100mL.

9. A method for preparing a cold-drawn and heat-set high-elasticity reinforcing strip composite material, characterized in that: Specifically, it includes the following steps: S1. Nano-calcium carbonate and silane coupling agent KH-550 are mixed at high speed at 100℃ for 10 min to obtain pretreated nano-calcium carbonate; modified thermoplastic polyurethane, ethylene-vinyl acetate copolymer and natural rubber are added to a mixer and mixed at 120℃ and 60 r / min for 5 min, then the temperature is raised to 140℃ and nitrogen protection is introduced for continued mixing for 20 min to obtain a preliminary mixture; then pretreated nano-calcium carbonate, diisononyl phthalate, compound antioxidant, UV absorber UV-9 and aramid short fiber are added to the mixer at 80℃, zinc stearate is added, and the mixture is mixed at 80 r / min for 10 min to obtain a mixture. S2. The mixture is fed into a twin-screw extruder, and the temperature is set as follows: Zone 1 175-185℃, Zone 2 185-195℃, Zone 3 195-205℃, screw speed 220-250 r / min, melt pressure 10MPa; at the same time, modified polyethylene terephthalate fiber and graphene are fed into the extruder, mixed thoroughly, and then extruded. S3. After extrusion molding, the material is stretched using a multi-stage cold drawing device. Specifically: the first stage stretching ratio is 1.2-1.5 times, and the stretching rate is 50 mm / min; the second stage stretching ratio is 1.8-2.0 times, and the stretching rate is 80 mm / min; the two stages of stretching are held for 1 minute, and infrared heating is used to locally preheat the surface of the elastic strip during the stretching process, with a preheating temperature of 40-50℃; after cold drawing, the elastic strip is heat-set by hot air circulation: held at 155℃ for 4 minutes, and then heated to 170℃ for 1 minute; then an 8-10 μm thick silicone coating is applied using a roller coating process, and after coating, it is cured in a 120℃ oven for 30 minutes to obtain a cold-drawn and heat-set high-elasticity elastic strip composite material.