High temperature resistant synchronous belt and preparation method thereof

Abstract

This invention discloses a high-temperature resistant synchronous belt and its preparation method, belonging to the field of polymer materials. The synchronous belt has a sea-island structure; the sea structure serves as the substrate, and the island structure consists of chopped reinforcing fibers. The chopped reinforcing fibers have a core-skin structure, including a core layer and a skin layer, connected by an adhesive layer. The substrate is a silicone rubber-nylon composite material; the mass ratio of the substrate to the chopped reinforcing fibers is 1:(0.42-1). This invention uses silicone rubber with excellent temperature resistance as the main substrate of the synchronous belt; a carbon-based ruthenium platinum catalyst catalyzes the hydrosilylation reaction between hydrogen-containing silicone oil and nylon; and sulfonated polyethersulfone is used as the core layer to prepare reinforcing fibers, enhancing the mechanical properties of the silicone rubber. This invention solves the problems in the prior art where the surface chemical inertness and poor compatibility with the substrate of the reinforcing material affect the performance and service life of the synchronous belt, and has application potential in the preparation of industrial transmission equipment and automotive engine peripheral transmission systems.

Description

Technical Field

[0001] This invention relates to the field of polymer materials technology, specifically to a high-temperature resistant synchronous belt and its preparation method. Background Technology

[0002] A synchronous belt is a conveyor belt that achieves precise synchronous operation by meshing its internal teeth with the grooves of the pulleys. It features high transmission efficiency, precise transmission ratio, low noise, low lubrication requirements, energy saving, and easy maintenance, and is widely used in the automotive, machinery, and chemical industries.

[0003] Traditional synchronous belt base materials mainly include chloroprene rubber, polyurethane, EPDM rubber, hydrogenated nitrile rubber, fluororubber, and silicone rubber. Among them, silicone rubber has become the preferred material for synchronous belts in extreme environments due to its excellent temperature resistance, oil resistance, UV resistance, and ozone resistance.

[0004] In addition to the base material, synchronous belts typically incorporate reinforcing materials to ensure their mechanical strength. These reinforcing materials usually include steel wire rope, aramid fiber, glass fiber, or carbon fiber. While these materials generally possess good toughness, high mechanical strength, strong insulation, and anti-aging properties, their surfaces are typically chemically inert, resulting in poor compatibility with the base material. This leads to inconsistent performance of the manufactured synchronous belt, affecting its performance and service life.

[0005] Therefore, there is an urgent need for a high-temperature-resistant synchronous belt with good compatibility between the substrate and the reinforcing material and strong temperature resistance to solve the above problems. Summary of the Invention

[0006] Therefore, this invention provides a high-temperature resistant synchronous belt and its preparation method to solve the problems in the prior art that affect the performance and service life of synchronous belts due to the surface chemical inertness of the reinforcing material and its poor compatibility with the substrate.

[0007] To achieve the above objectives, the present invention provides the following technical solution: According to a first aspect of the present invention, a high-temperature resistant synchronous belt is provided, wherein the material of the synchronous belt is a sea-island structure; wherein the sea structure is a substrate and the island structure is chopped reinforcing fiber; wherein the chopped reinforcing fiber is a core-skin structure, comprising a core layer and a skin layer, the core layer and the skin layer being connected by an adhesive layer; the substrate is a silicone rubber-nylon composite material; and the mass ratio of the substrate to the chopped reinforcing fiber is 1:(0.42-1).

[0008] Furthermore, the length of the chopped reinforcing fiber is 0.1-0.5 cm and the diameter is 10-30 μm; the core material of the chopped reinforcing fiber is sulfonated polyethersulfone, and the degree of sulfonation of the sulfonated polyethersulfone is 10-30%; the sheath material of the chopped reinforcing fiber is a composite material of SEBS and maleic anhydride-grafted SEBS, and the adhesive layer material is SEBS ionomer.

[0009] Furthermore, the SEBS ionomer is alkali-treated maleic anhydride-grafted SEBS; the mass ratio of SEBS to maleic anhydride-grafted SEBS in the skin material is (5-10):1; wherein the grafting rate of maleic anhydride-grafted SEBS is 1-4%.

[0010] Furthermore, in the alkali-treated maleic anhydride-grafted SEBS, the alkali-treated reagent reacts with the maleic anhydride groups of the maleic anhydride-grafted SEBS to generate an ionomer containing metal cations. The cations of the ionomer containing metal cations coordinate or interact with sulfonated polyethersulfone through hydrogen bonding. The alkali-treated reagent is specifically sodium hydroxide, calcium hydroxide, potassium hydroxide, barium hydroxide, or lithium hydroxide.

[0011] Furthermore, the substrate comprises the following components in parts by weight: 50-80 parts silicone rubber, 10-40 parts nylon, 1-3 parts antioxidant, 4-8 parts hydrogen-containing silicone oil, and 0.1-1 parts carbon-based ruthenium-platinum catalyst.

[0012] Furthermore, the silicone rubber is 107 silicone rubber, the antioxidant is antioxidant NBC and / or antioxidant BLE, and the nylon is long-chain nylon and / or semi-aromatic nylon.

[0013] According to a second aspect of the present invention, a method for preparing a high-temperature resistant synchronous belt is provided, which specifically includes the following steps: S1. Preparation of chopped fiber adhesive layer material: Maleic anhydride-grafted SEBS is thoroughly stirred and soaked in an alkali-treated reagent to form SEBS ionomers. After washing and drying, short-cut reinforcing fiber adhesive layer material is obtained. The ratio of maleic anhydride-grafted SEBS to alkali-treated reagent is 1g:(10-20)mL, and the concentration of the alkali-treated reagent is (0.02-0.3)M. S2. Preparation of chopped reinforcing fibers: After sulfonated polyethersulfone is spun, it is coated with chopped reinforcing fiber adhesive layer material and skin coating liquid in sequence, and then cut with a fiber chopped machine to obtain chopped reinforcing fiber; S3, Preparation of silicone rubber-nylon composite materials: After drying, nylon is melted in a batch mixer, and carbon-based ruthenium-platinum catalyst, silicone rubber, and hydrogen-containing silicone oil are added. The rotation speed and temperature are maintained to allow the components to react fully, thus obtaining a silicone rubber-nylon composite material. S4. Blend the silicone rubber-nylon composite material and chopped reinforcing fibers in a twin-screw extruder at 220-280℃, setting the twin-screw extruder speed to 100-300rpm and the blending time to 2-5min. After blending, place the mixture in a synchronous belt mold and press it at 170-190℃ and 10-15MPa for 3-8min to form a high-temperature resistant synchronous belt. After cooling to room temperature, a high-temperature resistant synchronous belt is obtained.

[0014] Furthermore, step S2 specifically includes the following steps: S201. Preparation of the chopped reinforcing fiber core layer: After drying, sulfonated polyethersulfone is heated and melted at 250-300℃ using a twin-screw extruder, and then melt-spun through a spinning assembly that can withstand at least 350℃. After cooling, oiling, stretching, setting, and winding, a chopped reinforcing fiber core layer is obtained; wherein, the spinning temperature is 260-310℃. S202. Dissolve the chopped fiber adhesive layer material in xylene at a ratio of 1g:20mL. After dissolving, coat the chopped fiber core layer with the chopped fiber adhesive layer material using a fiber impregnation machine and then dry. S203. SEBS and maleic anhydride-grafted SEBS are mixed in a certain proportion and dissolved in xylene at a material-to-liquid ratio of 1g:20mL to obtain a skin coating solution. The core layer coated with the adhesive layer is coated with the skin coating solution using a fiber impregnation machine, and then cut and dried using a fiber chopped strand machine to obtain chopped reinforcing fibers.

[0015] Furthermore, step S3 specifically includes the following steps: Preparation of S301 and carbon-based ruthenium-platinum catalysts: Soybean meal powder and deionized water were mixed evenly at a mass-volume ratio of 1g:(10-30)mL and placed in a hydrothermal reactor. After sealing, the mixture was reacted at 150-200℃ for 8-12 hours. After centrifugation, the supernatant was collected and freeze-dried to obtain carbon source powder. Ruthenium chloride and platinum tetrachloride were mixed and dissolved in N,N-dimethylformamide. After mixing thoroughly, carbon source powder was added. The ratio of ruthenium chloride, platinum tetrachloride, and N,N-dimethylformamide was 1 mmol:1 mmol:(10-20) mL; the ratio of ruthenium chloride, platinum tetrachloride, and carbon source powder was 1 mmol:1 mmol:2 g. After mixing all components thoroughly, the mixture was stirred at 50 rpm at 90-100℃ for 2-4 hours. After the reaction is complete, cool to room temperature and add 0.1-0.5M NaOH solution, the amount of which is 2%-10% of N,N-dimethylformamide; after the addition is complete, continue stirring until a precipitate is formed, centrifuge to collect the precipitate, and freeze-dry to obtain carbon-based ruthenium-platinum catalyst; S302. After drying the nylon, it is stirred and melted in a batch mixer at 150-180℃ and 30-80rpm. After melting, carbon-based ruthenium-platinum catalyst, silicone rubber, antioxidant and hydrogen-containing silicone oil are added. The speed and temperature are maintained and the reaction is continued for 30-60min to allow all components to react fully, so as to obtain silicone rubber-nylon composite material.

[0016] According to a third aspect of the present invention, the application of the above-described high-temperature resistant synchronous belt in the manufacture of industrial transmission equipment and peripheral transmission systems for automobile engines is provided.

[0017] The present invention has the following advantages: 1. This invention uses silicone rubber as the main substrate of the synchronous belt. Silicone rubber can be used for a long time in an ambient temperature of 250℃-300℃. It also has oil resistance, UV resistance and excellent ozone resistance, making it an excellent choice for preparing high-temperature resistant synchronous belts.

[0018] 2. This invention uses a carbon-based ruthenium-platinum catalyst to catalyze the hydrosilylation reaction between hydrogen-containing silicone oil and nylon, thereby enhancing the mechanical properties of silicone rubber. Nylon provides a mechanical skeleton for silicone rubber, enhancing the tensile and support properties of the synchronous belt.

[0019] 3. This invention uses rigid sulfonated polyethersulfone as the core layer of reinforcing fibers and SEBS ionomer as the adhesive layer. The cations of SEBS ionomer can coordinate or hydrogen bond with the sulfonic acid groups, sulfone groups or ether bonds of sulfonated polyethersulfone, and can also be compatible with the SEBS in the skin layer and the maleic anhydride-grafted SEBS, thereby enabling the rigid sulfonated polyethersulfone in the inner core layer to be uniformly dispersed in the silicone rubber-nylon substrate. In addition, sulfonated polyethersulfone itself has good thermal stability, which further improves the temperature resistance of the synchronous belt. Attached Figure Description

[0020] To more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are merely exemplary, and those skilled in the art can derive other embodiments based on the provided drawings without creative effort.

[0021] The structures, proportions, sizes, etc. illustrated in this specification are only for the purpose of assisting those skilled in the art in understanding and reading the content disclosed herein, and are not intended to limit the conditions under which the present invention can be implemented. Therefore, they have no substantial technical significance. Any modifications to the structure, changes in the proportions, or adjustments to the size, without affecting the effects and objectives that the present invention can produce, should still fall within the scope of the technical content disclosed in the present invention.

[0022] Figure 1 This invention provides a cross-sectional schematic diagram of a high-temperature resistant synchronous belt material and a cross-sectional schematic diagram of chopped reinforcing fibers, as shown in Embodiment 1 of the present invention; wherein, Figure 1 A is a cross-sectional schematic diagram of the high-temperature resistant synchronous belt material; 1 is the island structure of the material, i.e., chopped reinforcing fibers; 2 is the sea structure, i.e., the substrate. Figure 1 B is a schematic diagram of the cross-section of chopped reinforcing fibers, 3 is the core layer, 4 is the adhesive layer, and 5 is the skin layer.

[0023] Figure 2 Shore hardness histograms of high-temperature resistant synchronous belts prepared according to various embodiments and comparative examples provided in this invention; Figure 3 The tensile strength histograms of the high-temperature resistant synchronous belts prepared according to the various embodiments and comparative examples provided by the present invention. Detailed Implementation

[0024] The following specific embodiments illustrate the implementation of the present invention. Those skilled in the art can easily understand other advantages and effects of the present invention from the content disclosed in this specification. Obviously, the described embodiments are only some, not all, of the embodiments of the present invention. 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.

[0025] According to a first aspect of the present invention, a high-temperature resistant synchronous belt is provided, wherein the material of the synchronous belt is a sea-island structure; wherein the sea structure is a substrate and the island structure is chopped reinforcing fiber; wherein the chopped reinforcing fiber is a core-skin structure, including a core layer and a skin layer, the core layer and the skin layer being connected by an adhesive layer; the substrate is a silicone rubber-nylon composite material; the mass ratio of the substrate to the chopped reinforcing fiber is 1:(0.42-1).

[0026] The chopped reinforcing fibers have a length of 0.1-0.5 cm and a diameter of 10-30 μm. The core material of the chopped reinforcing fibers is sulfonated polyethersulfone with a sulfonation degree of 10-30%. The sheath material of the chopped reinforcing fibers is a composite material of SEBS and maleic anhydride-grafted SEBS, and the adhesive layer material is SEBS ionomer.

[0027] Among them, the SEBS ionomer is alkali-treated maleic anhydride-grafted SEBS; the mass ratio of SEBS to maleic anhydride-grafted SEBS in the skin material is (5-10):1; and the grafting rate of maleic anhydride-grafted SEBS is 1-4%.

[0028] In the case of alkali-treated maleic anhydride-grafted SEBS, the alkali-treated reagent reacts with the maleic anhydride groups of the maleic anhydride-grafted SEBS to generate an ionomer containing metal cations. The cations of the ionomer containing metal cations interact with sulfonated polyethersulfone through coordination or hydrogen bonding. The alkali-treated reagent is specifically sodium hydroxide, calcium hydroxide, potassium hydroxide, barium hydroxide, or lithium hydroxide.

[0029] The substrate comprises the following components by weight: 50-80 parts silicone rubber, 10-40 parts nylon, 1-3 parts antioxidant, 4-8 parts hydrogen-containing silicone oil, and 0.1-1 parts carbon-based ruthenium-platinum catalyst.

[0030] Among them, the silicone rubber is 107 silicone rubber, the antioxidant is antioxidant NBC and / or antioxidant BLE, and the nylon is long-chain nylon and / or semi-aromatic nylon.

[0031] According to a second aspect of the present invention, a method for preparing a high-temperature resistant synchronous belt is provided, which specifically includes the following steps: S1. Preparation of chopped fiber adhesive layer material: Maleic anhydride-grafted SEBS is thoroughly stirred and soaked in an alkali-treated reagent to form SEBS ionomers. After washing and drying, short-cut reinforcing fiber adhesive layer material is obtained. The ratio of maleic anhydride-grafted SEBS to alkali-treated reagent is 1g:(10-20)mL, and the concentration of alkali-treated reagent is (0.02-0.3)M. S2. Preparation of chopped reinforcing fibers: After sulfonated polyethersulfone is spun, it is coated with chopped reinforcing fiber adhesive layer material and skin coating liquid in sequence, and then cut with a fiber chopped machine to obtain chopped reinforcing fiber; S3, Preparation of silicone rubber-nylon composite materials: After drying, nylon is melted in a batch mixer, and carbon-based ruthenium-platinum catalyst, silicone rubber, and hydrogen-containing silicone oil are added. The rotation speed and temperature are maintained to allow the components to react fully, thus obtaining a silicone rubber-nylon composite material. S4. Blend the silicone rubber-nylon composite material and chopped reinforcing fibers in a twin-screw extruder at 220-280℃, setting the twin-screw extruder speed to 100-300rpm and the blending time to 2-5min. After blending, place the mixture in a synchronous belt mold and press it at 170-190℃ and 10-15MPa for 3-8min to form a high-temperature resistant synchronous belt. After cooling to room temperature, a high-temperature resistant synchronous belt is obtained.

[0032] Step S2 specifically includes the following steps: S201. Preparation of the chopped reinforcing fiber core layer: After drying, sulfonated polyethersulfone is heated and melted at 250-300℃ using a twin-screw extruder, and then melt-spun through a spinning assembly that can withstand at least 350℃. After cooling, oiling, stretching, setting, and winding, a chopped reinforcing fiber core layer is obtained; wherein, the spinning temperature is 260-310℃. S202. Dissolve the chopped fiber adhesive layer material in xylene at a ratio of 1g:20mL. After dissolving, coat the chopped fiber core layer with the chopped fiber adhesive layer material using a fiber impregnation machine and then dry. S203. SEBS and maleic anhydride-grafted SEBS are mixed in a certain proportion and dissolved in xylene at a material-to-liquid ratio of 1g:20mL to obtain a skin coating solution. The core layer coated with the adhesive layer is coated with the skin coating solution using a fiber impregnation machine, and then cut and dried using a fiber chopped strand machine to obtain chopped reinforcing fibers.

[0033] Step S3 specifically includes the following steps: Preparation of S301 and carbon-based ruthenium-platinum catalysts: Soybean meal powder and deionized water were mixed evenly at a mass-volume ratio of 1g:(10-30)mL and placed in a hydrothermal reactor. After sealing, the mixture was reacted at 150-200℃ for 8-12 hours. After centrifugation, the supernatant was collected and freeze-dried to obtain carbon source powder. Ruthenium chloride and platinum tetrachloride were mixed and dissolved in N,N-dimethylformamide. After mixing thoroughly, carbon source powder was added. The ratio of ruthenium chloride, platinum tetrachloride, and N,N-dimethylformamide was 1 mmol:1 mmol:(10-20) mL; the ratio of ruthenium chloride, platinum tetrachloride, and carbon source powder was 1 mmol:1 mmol:2 g. After mixing all components thoroughly, the mixture was stirred at 50 rpm at 90-100℃ for 2-4 hours. After the reaction is complete, cool to room temperature and add 0.1-0.5M NaOH solution, the amount of which is 2%-10% of N,N-dimethylformamide; after the addition is complete, continue stirring until a precipitate is formed, centrifuge to collect the precipitate, and freeze-dry to obtain carbon-based ruthenium-platinum catalyst; S302. After drying the nylon, it is stirred and melted in a batch mixer at 150-180℃ and 30-80rpm. After melting, carbon-based ruthenium-platinum catalyst, silicone rubber, antioxidant and hydrogen-containing silicone oil are added. The speed and temperature are maintained and the reaction is continued for 30-60min to allow all components to react fully, so as to obtain silicone rubber-nylon composite material.

[0034] To better illustrate the technical path of the present invention, the following embodiments and comparative examples are provided.

[0035] Example 1 S1. Preparation of chopped fiber adhesive layer material: 3 kg of maleic anhydride-grafted SEBS (purchased from Mitsui Chemicals, Japan, with a grafting rate of 1.7%) was thoroughly stirred and soaked in 30 L of 0.1 M Ba(OH)2 solution to form SEBS ionomer. After washing with anhydrous ethanol and drying, the short-cut reinforcing fiber adhesive layer material was obtained. S2. Preparation of chopped reinforcing fibers: S201. Preparation of the chopped reinforcing fiber core layer: Sulfonated polyethersulfone (purchased from Konishi Chemical Industry Co., Ltd., Japan, model: XH5011YYWDRK, sulfonation degree: 20%) was dried and then melted at 270°C using a twin-screw extruder. The melt was then spun through a spinning assembly that could withstand at least 350°C. After cooling, oiling, stretching, setting, and winding, a chopped reinforcing fiber core layer was obtained. The spinning temperature was 280°C. S202. Dissolve 1000g of chopped fiber adhesive layer material in 20L of xylene. After dissolving, coat the chopped fiber core layer with the chopped fiber adhesive layer material using a fiber impregnation machine and then dry it. S203. Mix 750g of SEBS and 150g of maleic anhydride-grafted SEBS and dissolve them in 18L of xylene to obtain a skin coating solution; coat the core layer coated with the adhesive layer with the skin coating solution using a fiber impregnation machine, cut it into 0.1cm lengths using a fiber chopped strand machine and dry it to obtain chopped reinforcing fibers. S3, Preparation of silicone rubber-nylon composite materials: Preparation of S301 and carbon-based ruthenium-platinum catalysts: 50g of soybean meal powder was mixed evenly with 1L of deionized water and placed in a hydrothermal reactor. After sealing, the mixture was reacted at 180℃ for 9 hours. After centrifugation, the supernatant was collected and freeze-dried to obtain carbon source powder. The preparation was carried out twice, i.e. 100g of soybean meal powder was reacted with 2L of deionized water. 5.18 g of ruthenium chloride (purchased from Shanghai Maclean Biochemical Technology Co., Ltd., CAS: 13454-96-1) and 8.43 g of platinum tetrachloride (purchased from Shanghai Maclean Biochemical Technology Co., Ltd., CAS: 10049-08-8) were mixed and dissolved in 325 mL of N,N-dimethylformamide. After mixing evenly, 50 g of carbon source powder was added. All components were mixed evenly and the mixture was stirred at 95 °C and 50 rpm for 3 h. After the reaction was completed, the mixture was cooled to room temperature, and 10 mL of 0.1 M NaOH solution was added. After the addition was complete, the mixture was stirred until a precipitate was formed. The precipitate was then centrifuged and freeze-dried to obtain the carbon-based ruthenium-platinum catalyst. S302. 1.25 kg of PA11 was dried and melted in a batch mixer at 170 °C and 50 rpm. After melting, 25 g of carbon-based ruthenium-platinum catalyst, 3325 g of 107 silicone rubber (purchased from Shandong Guohua Chemical Co., Ltd.), 0.1 kg of antioxidant NBC (purchased from Guangzhou Shanghe Chemical Technology Co., Ltd., CAS: 13927-77-0) and 0.3 kg of hydrogen-containing silicone oil were added. The speed and temperature were maintained and the reaction was continued for 30 min to allow all components to react fully, thus obtaining a silicone rubber-nylon composite material. S4. 3.5 kg of silicone rubber-nylon composite material and 1.5 kg of chopped reinforcing fiber were blended in a twin-screw extruder at 250°C. The twin-screw extruder speed was set to 200 rpm and the blending time was 5 min. After blending, the mixture was placed in a synchronous belt mold and pressed at 170°C and 15 MPa for 5 min to form a high-temperature resistant synchronous belt. After cooling to room temperature, a high-temperature resistant synchronous belt was obtained.

[0036] The synchronous belt prepared in this embodiment is a sea-island structure; wherein, the sea structure (2) is the substrate, and the island structure (1) is a short-cut reinforcing fiber ( Figure 1 A); among which, the chopped reinforcing fibers have a core-skin structure ( Figure 1 B), including a core layer (3) and a skin layer (5), with the core layer and skin layer connected by an adhesive layer (4).

[0037] Example 2 This embodiment is based on Embodiment 1, except that NaOH is used instead of Ba(OH)2 in the preparation of the chopped reinforcing fiber adhesive layer material, while the other specific parameters are the same as in Embodiment 1.

[0038] Example 3 This embodiment is based on Embodiment 1, except that in the preparation of the chopped reinforcing fiber adhesive layer material, 20L of 0.02M Ca(OH)2 is used instead of 10L of 0.1M Ba(OH)2, and the other specific parameters are the same as in Embodiment 1.

[0039] Example 4 This embodiment is based on Example 1, except that the amount of SEBS and maleic anhydride-grafted SEBS in S203 is: 1000g of SEBS and 100g of maleic anhydride-grafted SEBS are mixed and dissolved in 20L of xylene. The other specific parameters are the same as in Example 1.

[0040] Example 5 This embodiment is based on Embodiment 1, except that the amount of silicone rubber and chopped reinforcing fiber in step S4 is: 2.5 kg of silicone rubber-nylon composite material and 2.5 kg of chopped reinforcing fiber are blended at 250°C using a twin-screw extruder, and the other specific parameters are the same as in Embodiment 1.

[0041] Comparative Example 1 S1. Preparation of silicone rubber-nylon composite material: Preparation of S101 and carbon-based ruthenium-platinum catalysts: 50g of soybean meal powder was mixed evenly with 1L of deionized water and placed in a hydrothermal reactor. After sealing, the mixture was reacted at 180℃ for 9 hours. After centrifugation, the supernatant was collected and freeze-dried to obtain carbon source powder. The preparation was carried out twice, i.e. 100g of soybean meal powder was reacted with 2L of deionized water. 5.18 g of ruthenium chloride and 8.43 g of platinum tetrachloride were mixed and dissolved in 325 mL of N,N-dimethylformamide. After mixing evenly, 50 g of carbon source powder was added. All components were mixed evenly and then stirred at 95 °C and 50 rpm for 3 h. After the reaction was completed, the mixture was cooled to room temperature, and 10 mL of 0.1 M NaOH solution was added. After the addition was complete, the mixture was stirred until a precipitate was formed. The precipitate was then centrifuged and freeze-dried to obtain the carbon-based ruthenium-platinum catalyst. S102. After drying 1.25 kg of PA11, it was melted in a batch mixer at 170 °C and 50 rpm. After melting, 25 g of carbon-based ruthenium-platinum catalyst, 3325 g of 107 silicone rubber, 0.1 kg of antioxidant NBC and 0.3 kg of hydrogen-containing silicone oil were added. The speed and temperature were maintained and the reaction was continued for 30 min to allow all components to react fully, thus obtaining silicone rubber-nylon composite material. S2. Place 5kg of silicone rubber-nylon composite material in a synchronous belt mold and press it at 170℃ and 15MPa for 5min to form a high-temperature resistant synchronous belt. After cooling to room temperature, a high-temperature resistant synchronous belt is obtained.

[0042] This comparative example is based on Example 1, except that steps S1 and S2 are not performed, i.e., short-cut reinforcing fibers are not added, while the other specific parameters are the same as in Example 1.

[0043] Comparative Example 2 S1. Preparation of chopped reinforcing fibers: S101. Preparation of the chopped reinforcing fiber core layer: After drying, sulfonated polyethersulfone is heated and melted at 270°C using a twin-screw extruder, and then melt-spun through a spinning assembly that can withstand at least 350°C. After cooling, oiling, stretching, setting, and winding, a chopped reinforcing fiber core layer is obtained; wherein, the spinning temperature is 280°C. S102. Mix 750g of SEBS and 150g of maleic anhydride-grafted SEBS and dissolve them in 18L of xylene to obtain a skin coating solution; coat the chopped reinforcing fiber core layer with the skin coating solution using a fiber impregnation machine, cut it into 0.1cm lengths using a fiber chopped strand machine and dry it to obtain chopped reinforcing fibers. S2. Preparation of silicone rubber-nylon composite materials: Preparation of S201 and carbon-based ruthenium-platinum catalysts: 50g of soybean meal powder was mixed evenly with 1L of deionized water and placed in a hydrothermal reactor. After sealing, the mixture was reacted at 180℃ for 9 hours. After centrifugation, the supernatant was collected and freeze-dried to obtain carbon source powder. The preparation was carried out twice, i.e. 100g of soybean meal powder was reacted with 2L of deionized water. 5.18 g of ruthenium chloride and 8.43 g of platinum tetrachloride were mixed and dissolved in 325 mL of N,N-dimethylformamide. After mixing evenly, 50 g of carbon source powder was added. All components were mixed evenly and then stirred at 95 °C and 50 rpm for 3 h. After the reaction was completed, the mixture was cooled to room temperature, and 10 mL of 0.1 M NaOH solution was added. After the addition was complete, the mixture was stirred until a precipitate was formed. The precipitate was then centrifuged and freeze-dried to obtain the carbon-based ruthenium-platinum catalyst. S202. After drying 1.25 kg of PA11, it was melted in a batch mixer at 170 °C and 50 rpm. After melting, 25 g of carbon-based ruthenium-platinum catalyst, 3325 g of 107 silicone rubber, 0.1 kg of antioxidant NBC and 0.3 kg of hydrogen-containing silicone oil were added. The speed and temperature were maintained and the reaction was continued for 30 min to allow all components to react fully, thus obtaining silicone rubber-nylon composite material. S3. 3.5 kg of silicone rubber-nylon composite material and 1.5 kg of chopped reinforcing fiber were blended in a twin-screw extruder at 250°C. The twin-screw extruder speed was set to 200 rpm and the blending time was 5 min. After blending, the mixture was placed in a synchronous belt mold and pressed at 170°C and 15 MPa for 5 min to form a high-temperature resistant synchronous belt. After cooling to room temperature, a high-temperature resistant synchronous belt was obtained.

[0044] This comparative example is based on Example 1, except that steps S1 and S202 are not performed, i.e., no chopped reinforcing fiber adhesive layer is added, while the other specific parameters are the same as in Example 1.

[0045] Comparative Example 3 S1. Preparation of chopped fiber adhesive layer material: 3 kg of maleic anhydride-grafted SEBS was thoroughly stirred and soaked in 30 L of 0.1 M Ba(OH)2 solution to form SEBS ionomer. After washing with anhydrous ethanol and drying, the short-cut reinforcing fiber adhesive layer material was obtained. S2. Preparation of chopped reinforcing fibers: S201. Preparation of the chopped reinforcing fiber core layer: After drying, sulfonated polyethersulfone is heated and melted at 270°C using a twin-screw extruder, and then melt-spun through a spinning assembly that can withstand at least 350°C. After cooling, oiling, stretching, setting, and winding, a chopped reinforcing fiber core layer is obtained; wherein, the spinning temperature is 280°C. S202. Dissolve 1000g of chopped fiber adhesive layer material in 20L of xylene. After dissolving, coat the chopped fiber core layer with the chopped fiber adhesive layer material using a fiber impregnation machine and then dry it. S203. Mix 750g of SEBS and 150g of maleic anhydride-grafted SEBS and dissolve them in 18L of xylene to obtain a skin coating solution; coat the core layer coated with the adhesive layer with the skin coating solution using a fiber impregnation machine, cut it into 0.1cm lengths using a fiber chopped strand machine and dry it to obtain chopped reinforcing fibers. S3, Preparation of silicone rubber-nylon composite materials: 1.55 kg of PA11 was dried and melted in a batch mixer at 170 °C and 50 rpm. After melting, 3350 g of 107 silicone rubber and 0.1 kg of antioxidant NBC were added. The speed and temperature were maintained and the reaction was continued for 30 min to allow all components to react fully, thus obtaining a silicone rubber-nylon composite material. S4. 3.5 kg of silicone rubber-nylon composite material and 1.5 kg of chopped reinforcing fiber were blended in a twin-screw extruder at 250°C. The twin-screw extruder speed was set to 200 rpm and the blending time was 5 min. After blending, the mixture was placed in a synchronous belt mold and pressed at 170°C and 15 MPa for 5 min to form a high-temperature resistant synchronous belt. After cooling to room temperature, a high-temperature resistant synchronous belt was obtained.

[0046] This comparative example is based on Example 1, except that step S301 is omitted and no hydrogen-containing silicone oil and carbon-based ruthenium-platinum catalyst are added in step S302, i.e. no hydrosilylation reaction is performed. The other specific parameters are the same as in Example 1.

[0047] Test case To further illustrate the beneficial effects of the present invention, the synchronization belts prepared in each embodiment and comparative example were subjected to the following tests: 1. The Shore hardness of the synchronous belt was determined according to the method of GB / T 531-1999, and the results were recorded. Figure 2 ; 2. The tensile strength of the synchronous belt was determined according to the method of GB / T 528-2009; the tensile rate was set to 100 mm / min, and the results were recorded. Figure 3 ; 3. The heat aging resistance and low temperature resistance of the synchronous belt were determined using the following method, specifically including the following steps: The synchronous belts prepared in each embodiment and comparative example were aged in a high temperature / low temperature environment, and after being restored to room temperature, the tensile strength was measured and the tensile strength retention rate was recorded. The tensile strength retention rate is expressed by the formula: calculate; The high-temperature aging condition was aging at 90℃ for 180 hours, and the low-temperature aging condition was aging at -30℃ for 60 hours. The results are recorded in Table 1.

[0048] Table 1. Heat aging resistance and low temperature resistance of high-temperature synchronous belts Example 1 57.7±5.2 58.7±5.5 95.5±8.3 97.2±8.8 Example 2 55.2±5.1 56.6±5.2 94.1±8.0 96.5±8.5 Example 3 52.9±4.9 54.2±4.7 92.8±7.9 95.1±8.4 Example 4 51.0±5.0 52.6±5.1 92.3±8.2 95.2±8.0 Example 5 50.3±5.0 51.6±4.5 91.7±7.6 93.9±7.7 Comparative Example 1 39.5±3.3 43.9±4.0 88.2±8.2 98.0±7.0 Comparative Example 2 45.0±3.9 48.1±4.2 90.1±7.7 96.3±8.0 Comparative Example 3 32.0±3.0 33.6±3.1 86.0±7.5 90.2±6.9 Depend on Figure 2 It can be seen that the high-temperature resistant synchronous belts prepared in the embodiments of the present invention exhibit good Shore hardness, all exceeding 80 (A), meaning they can provide good support to meet the practical applications of synchronous belts. Compared with Example 1, the Shore hardness of Examples 2 and 3 decreased by 4.3% and 10.9%, respectively. The reason is that Ba... 2+ It is a divalent ion, while Na + The two are monovalent ions, and their coordination and hydrogen bonding abilities with sulfonated polyethersulfone differ, resulting in different internal bonding abilities of the chopped reinforcing fibers, thus affecting the synchronous belt hardness. In Example 3, calcium hydroxide was used instead of barium hydroxide. Calcium hydroxide has limited solubility in water, resulting in fewer cations binding to the core layer compared to Example 1, thus affecting the synchronous belt performance. The Shore hardness of Example 4 was slightly lower than that of Example 1. This is because maleic anhydride-grafted SEBS is an important compatibilizer for the connection between the chopped reinforcing fibers and the matrix. Its reduced content leads to decreased internal compatibility of the system. In Comparative Example 2, no adhesive layer was added to the chopped reinforcing fibers, resulting in poor internal bonding of the fibers, thus affecting the synchronous belt performance. Example 5 increased the content of chopped reinforcing fibers in the system. The increased content of rigid fibers resulted in Example 5 exhibiting the highest Shore hardness; the Shore hardness of Comparative Example 1 was only 66 (A), the lowest among all groups, which also confirms this point. Comparative Example 3 did not add hydrogen-containing silicone oil and carbon-based ruthenium-platinum catalyst. These two components are important components for the hydrosilylation of silicone rubber-nylon composite materials. Their absence prevents the matrix system from forming a stable and cured network structure. Even if the matrix contains fibers, it cannot effectively bear the load. In fact, stress concentration can make the matrix softer, thus affecting the Shore hardness of the synchronous belt.

[0049] Figure 3 The bar chart shows the tensile strength of the high-temperature resistant synchronous belts prepared in the various embodiments and comparative examples provided by this invention. It can be seen that the room-temperature tensile strength of the embodiment group is significantly better than that of the comparative example group. This is because the chopped reinforcing fibers in the high-temperature resistant synchronous belts prepared by this invention provide the supporting strength of the system, while the adhesive layer provides the compatibility and bonding strength within the fibers. The hydrogen-containing silicone oil and carbon-based ruthenium-platinum catalyst provide the raw materials and catalysts for the hydrosilylation reaction, which can enhance the internal strength of the substrate. The absence of these conditions significantly reduces the tensile strength of the synchronous belt.

[0050] As shown in Table 1, the synchronous belts prepared in all embodiments and comparative examples retained more than 90% of their tensile strength after aging at -30℃ for 60 hours, and the low-temperature tensile strength retention rate was higher than that under high-temperature conditions. This indicates that the synchronous belts prepared by this invention have excellent low-temperature resistance, and this performance mainly originates from the silicone rubber in the substrate. Furthermore, Comparative Example 1 showed a higher low-temperature aging tensile strength retention rate than the embodiment group, reaching 98.0%. This may be because silicone rubber itself has excellent cold resistance, with similar retention rates, but the addition of 30% rigid SPES fiber resulted in different thermal shrinkage coefficients between the two materials at low temperatures, leading to micro-stress at the interface and affecting the tensile strength retention rate of the synchronous belt. The synchronous belts prepared by this invention also exhibited excellent high-temperature aging resistance; after aging at 90℃ for 180 hours, the tensile strength retention rate was still higher than 85%. The above results demonstrate that the high-temperature resistant synchronous belts prepared by this invention have excellent high-temperature and low-temperature aging resistance. It is worth noting that Example 5 exhibited the highest Shore hardness among the Example groups, but its tensile strength at room temperature, 90°C, and -30°C, as well as its tensile strength retention at 90°C and -30°C, were the lowest among the Example groups. This is because the chopped reinforcing fiber content in Example 5 was the highest among the Example groups. The increased content of rigid reinforcing fibers led to an increase in the rigidity and brittleness of the synchronous belt material, thus resulting in its lower tensile strength.

[0051] Although the present invention has been described in detail above with general descriptions and specific embodiments, modifications or improvements can be made to it, which will be obvious to those skilled in the art. Therefore, all such modifications or improvements made without departing from the spirit of the present invention fall within the scope of protection claimed by the present invention.

Claims

1. A high-temperature resistant synchronous belt, characterized in that, The material of the synchronous belt has a sea-island structure; Among them, the ocean structure is the base, and the island structure is the short-cut reinforcing fiber; The chopped reinforcing fiber has a core-skin structure, including a core layer and a skin layer, which are connected by an adhesive layer; the substrate is a silicone rubber-nylon composite material; and the mass ratio of the substrate to the chopped reinforcing fiber is 1:(0.42-1).

2. The high temperature resistant synchronous belt of claim 1, wherein, The chopped reinforcing fibers have a length of 0.1-0.5 cm and a diameter of 10-30 μm; the core material of the chopped reinforcing fibers is sulfonated polyether sulfone, and the degree of sulfonation of the sulfonated polyether sulfone is 10-30%; the sheath material of the chopped reinforcing fibers is a composite material of SEBS and maleic anhydride-grafted SEBS, and the adhesive layer material is SEBS ionomer.

3. The high temperature resistant synchronous belt of claim 2, wherein, The SEBS ionomer is alkali-treated maleic anhydride-grafted SEBS; the mass ratio of SEBS to maleic anhydride-grafted SEBS in the skin material is (5-10):1; wherein the grafting rate of maleic anhydride-grafted SEBS is 1-4%.

4. The high temperature resistant synchronous belt of claim 3, wherein, In the alkali-treated maleic anhydride-grafted SEBS, the alkali-treated reagent reacts with the maleic anhydride groups of the maleic anhydride-grafted SEBS to generate an ionomer containing metal cations. The cations of the ionomer containing metal cations interact with sulfonated polyethersulfone through coordination or hydrogen bonding. The alkali-treated reagent is specifically sodium hydroxide, calcium hydroxide, potassium hydroxide, barium hydroxide, or lithium hydroxide.

5. The high temperature resistant synchronous belt of claim 1, wherein, The substrate comprises the following components in parts by weight: 50-80 parts silicone rubber, 10-40 parts nylon, 1-3 parts antioxidant, 4-8 parts hydrogen-containing silicone oil, and 0.1-1 parts carbon-based ruthenium-platinum catalyst.

6. The high temperature resistant synchronous belt of claim 5, wherein, The silicone rubber is 107 silicone rubber, the antioxidant is antioxidant NBC and / or antioxidant BLE, and the nylon is long-chain nylon and / or semi-aromatic nylon.

7. A method for preparing a high-temperature resistant synchronous belt, used to prepare the high-temperature resistant synchronous belt according to any one of claims 1-6, characterized in that, Specifically, the following steps are included: S1. Preparation of chopped fiber adhesive layer material: Maleic anhydride-grafted SEBS is thoroughly stirred and soaked in an alkali-treated reagent to form SEBS ionomers. After washing and drying, short-cut reinforcing fiber adhesive layer material is obtained. The ratio of maleic anhydride-grafted SEBS to alkali-treated reagent is 1g:(10-20)mL, and the concentration of the alkali-treated reagent is (0.02-0.3)M. S2. Preparation of chopped reinforcing fibers: After sulfonated polyethersulfone is spun, it is coated with chopped reinforcing fiber adhesive layer material and skin coating liquid in sequence, and then cut with a fiber chopped machine to obtain chopped reinforcing fiber; S3, Preparation of silicone rubber-nylon composite materials: After drying, nylon is melted in a batch mixer, and carbon-based ruthenium-platinum catalyst, silicone rubber, and hydrogen-containing silicone oil are added. The rotation speed and temperature are maintained to allow the components to react fully, thus obtaining a silicone rubber-nylon composite material. S4. Blend the silicone rubber-nylon composite material and chopped reinforcing fibers in a twin-screw extruder at 220-280℃, setting the twin-screw extruder speed to 100-300rpm and the blending time to 2-5min. After blending, place the mixture in a synchronous belt mold and press it at 170-190℃ and 10-15MPa for 3-8min to form a high-temperature resistant synchronous belt. After cooling to room temperature, a high-temperature resistant synchronous belt is obtained.

8. The method for preparing the high-temperature resistant synchronous belt as described in claim 7, characterized in that, Step S2 specifically includes the following steps: S201. Preparation of the chopped reinforcing fiber core layer: After drying, sulfonated polyethersulfone is heated and melted at 250-300℃ using a twin-screw extruder, and then melt-spun through a spinning assembly that can withstand at least 350℃. After cooling, oiling, stretching, setting, and winding, a chopped reinforcing fiber core layer is obtained; wherein, the spinning temperature is 260-310℃. S202. Dissolve the chopped fiber adhesive layer material in xylene at a ratio of 1g:20mL. After dissolving, coat the chopped fiber core layer with the chopped fiber adhesive layer material using a fiber impregnation machine and then dry. S203. SEBS and maleic anhydride-grafted SEBS are mixed in a certain proportion and dissolved in xylene at a material-to-liquid ratio of 1g:20mL to obtain a skin coating solution. The core layer coated with the adhesive layer is coated with the skin coating solution using a fiber impregnation machine, and then cut and dried using a fiber chopped strand machine to obtain chopped reinforcing fibers.

9. The method for preparing the high-temperature resistant synchronous belt as described in claim 7, characterized in that, Step S3 specifically includes the following steps: Preparation of S301 and carbon-based ruthenium-platinum catalysts: Soybean meal powder and deionized water were mixed evenly at a mass-volume ratio of 1g:(10-30)mL and placed in a hydrothermal reactor. After sealing, the mixture was reacted at 150-200℃ for 8-12 hours. After centrifugation, the supernatant was collected and freeze-dried to obtain carbon source powder. Ruthenium chloride and platinum tetrachloride were mixed and dissolved in N,N-dimethylformamide. After mixing thoroughly, carbon source powder was added. The ratio of ruthenium chloride, platinum tetrachloride, and N,N-dimethylformamide was 1 mmol:1 mmol:(10-20) mL; the ratio of ruthenium chloride, platinum tetrachloride, and carbon source powder was 1 mmol:1 mmol:2 g. After mixing all components thoroughly, the mixture was stirred at 50 rpm at 90-100℃ for 2-4 hours. After the reaction is complete, cool to room temperature and add 0.1-0.5M NaOH solution, the amount of which is 2%-10% of N,N-dimethylformamide; after the addition is complete, continue stirring until a precipitate is formed, centrifuge to collect the precipitate, and freeze-dry to obtain carbon-based ruthenium-platinum catalyst; S302. After drying the nylon, it is stirred and melted in a batch mixer at 150-180℃ and 30-80rpm. After melting, carbon-based ruthenium-platinum catalyst, silicone rubber, antioxidant and hydrogen-containing silicone oil are added. The speed and temperature are maintained and the reaction is continued for 30-60min to allow all components to react fully, so as to obtain silicone rubber-nylon composite material.

10. The application of the high-temperature resistant synchronous belt as described in any one of claims 1-6 in the manufacture of industrial transmission equipment and automotive engine peripheral transmission systems.

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