Temperature-resistant and moisture-resistant composite material for preparing bearing retainer and preparation method of temperature-resistant and moisture-resistant composite material

Abstract

The invention discloses a temperature-resistant and moisture-resistant composite material for preparing a bearing retainer and a preparation method of the temperature-resistant and moisture-resistant composite material, and belongs to the technical field of bearing retainers. The composite material is prepared from the following components in parts by weight: 100-120 parts of POM, 10-20 parts of a temperature-resistant additive, 5-8 parts of superfine polytetrafluoroethylene powder, 5-10 parts of filler, 3-4 parts of a compatilizer, 0.3-0.5 part of an antioxidant and 0.2-0.4 part of a lubricant. The bearing retainer prepared from the composite material has excellent temperature resistance and moisture resistance, excellent dimensional stability and good mechanical properties can be kept in a high-temperature, low-temperature or high-humidity environment, and the requirement for long service life of the bearing retainer is met.

Description

Technical Field

[0001] This application relates to a temperature- and moisture-resistant composite material for preparing bearing cages and a method for preparing the same, belonging to the field of bearing cage technology. Background Technology

[0002] As a core component of mechanical transmission systems, bearings directly determine the service life and efficiency of the entire equipment through their operational reliability. Bearing cages, as a crucial part of bearings, bear the core functions of supporting rolling elements, guiding their movement, isolating impurities, and optimizing lubrication distribution. Their performance limits often become the bottleneck restricting bearing applications in extreme environments. With the development of modern industry towards high-end and extreme environments, the application scenarios for bearings have gradually expanded from traditional ambient temperature and humidity environments to harsh working conditions such as aerospace, automotive engine compartments, offshore wind power, chemical equipment, cryogenic cold chains, and underground engineering.

[0003] Traditional polyoxymethylene (POM) cages are low in cost and have excellent processability, but their temperature and humidity resistance are significant drawbacks. Materials like POM exhibit significant performance degradation above 120°C and have poor resistance to high humidity aging. They are prone to hydrolytic degradation in high-humidity environments, leading to a substantial decrease in impact strength and limiting their applications. Therefore, developing bearing cages with excellent temperature resistance, humidity resistance, resistance to damp heat aging, and stable mechanical properties has become a key technological direction for overcoming the bottlenecks in bearing applications in extreme environments. Summary of the Invention

[0004] To address the aforementioned issues, this application provides a temperature- and moisture-resistant composite material for manufacturing bearing cages. Bearing cages made from this composite material exhibit excellent temperature and moisture resistance, maintaining excellent dimensional stability and good mechanical properties in high-temperature, low-temperature, or high-humidity environments, thus meeting the long-life requirements of bearing cages.

[0005] According to one aspect of this application, a temperature-resistant and moisture-resistant composite material for preparing bearing cages is provided, characterized in that, by weight parts, it comprises: 100-120 parts of POM, 10-20 parts of temperature-resistant additives, 5-8 parts of ultrafine polytetrafluoroethylene powder, 5-10 parts of filler, 3-4 parts of compatibilizer, 0.3-0.5 parts of antioxidant, and 0.2-0.4 parts of lubricant; The structural formula of the temperature-resistant additive is as follows: .

[0006] When POM is exposed to high temperatures, the hemiacetal structure at the end of the molecular chain breaks, generating formaldehyde free radicals, which trigger chain depolymerization, leading to a rapid collapse of the material's properties. The heat-resistant additive contains NO bonds, which can decompose at high temperatures to generate nitric oxide free radicals (-NO·). These free radicals can rapidly capture free radicals generated by POM degradation, terminating the chain reaction, slowing down the depolymerization process, and thus improving the temperature resistance of the composite material.

[0007] Meanwhile, the presence of carbonyl groups in the heat-resistant additives can react with the terminal hydroxyl groups of POM, blocking the initiation site of the POM matrix depolymerization reaction, thereby increasing the thermal decomposition temperature of the composite material. Furthermore, carbonyl groups are highly polar groups, which can form dipole-dipole interactions between POM molecular chains, enhancing the physical cross-linking force between chains. This increases the resistance to molecular chain segment movement, enabling the composite material to maintain higher mechanical strength at high temperatures and resist softening and deformation.

[0008] In addition, the methyl substituents of the tertiary amines in the heat-resistant additives have a certain steric hindrance effect, which can prevent small molecules such as oxygen and water from penetrating into the interior of POM, reduce the occurrence of thermal oxidation degradation, and thus improve the material's heat deformation resistance.

[0009] Ultrafine PTFE powder has no polar functional groups (such as hydroxyl or carboxyl groups) in its molecular chains, and therefore no hydrogen bonds with polar water molecules. The fluorine atoms are tightly packed, forming a hydrophobic protective layer, preventing water molecules from adsorbing or penetrating into the interstices of the molecular chains. Therefore, it absorbs almost no water and exhibits no volume expansion. Furthermore, due to the increased brittleness of POM at low temperatures, the addition of ultrafine PTFE powder can help disperse stress. Its wide operating temperature range allows it to be synergistically combined with heat-resistant additives to improve the temperature and moisture resistance of bearing cages. In addition, the good dispersibility, lack of self-agglomeration, absence of electrostatic effects, high self-lubrication, and low coefficient of friction of ultrafine PTFE powder enhance the material's processing performance.

[0010] Meanwhile, due to the small particle size of ultrafine polytetrafluoroethylene powder, it can be uniformly dispersed in the matrix material. There is no need to worry that the large particle size will easily lead to agglomeration, which will not only fail to provide hydrophobicity, but may even reduce the density of the composite material and affect its strength. There is also no need to worry that the low temperature during extrusion granulation will make it difficult to melt. It can play its role completely through physical blending.

[0011] Based on this, the amount of heat-resistant additives and ultrafine polytetrafluoroethylene powder added is also crucial. If there is too much heat-resistant additive, its compatibility with other components will be affected due to its large steric hindrance; if there is too much ultrafine polytetrafluoroethylene powder, the strength of the material will be reduced due to its low strength and modulus.

[0012] Optionally, it also includes 10-15 parts of modified glass fiber, wherein the modified glass fiber is obtained by modification with butyl carbamate.

[0013] Modified glass fiber possesses excellent mechanical properties. Its addition to POM provides a high-modulus skeleton for the POM matrix, significantly improving the material's tensile strength, flexural strength, and impact toughness. Furthermore, due to the low coefficient of linear expansion of modified glass fiber, the composite material exhibits good dimensional stability under varying temperature and humidity conditions.

[0014] Optionally, the modified glass fiber is prepared by: S1 is used to activate glass fibers; S2 involves completely immersing the activated glass fiber in a 10wt%-15wt% butyl carbamate solution, ultrasonically treating it at 40-50℃ for 2-4 hours, and then removing and drying the modified glass fiber to obtain the final product.

[0015] Glass fiber is often added as a reinforcing phase to enhance the rigidity and strength of POM, but this leads to a decrease in POM toughness, making the material brittle and reducing its impact resistance. In addition, the large number of silanol groups on its surface can easily form hydrogen bonds with water molecules, allowing water molecules to penetrate along the interfacial gaps, resulting in poor moisture resistance of the material. Therefore, it is necessary to modify it to overcome the existing drawbacks.

[0016] The glass fiber surface contains a large number of silanol groups. This application uses urethane-modified glass fiber, where the amino groups in the urethane molecule form stable Si-N covalent bonds with the silanol groups, allowing urethane to be grafted onto the glass fiber surface. The ester groups in the molecule can further cross-link with the amino groups of adjacent modified molecules or the residual hydroxyl groups on the glass fiber surface, forming a three-dimensional network modified layer. This reduces the surface friction coefficient of the fiber, prevents agglomeration, and ensures uniform fiber distribution within the POM matrix, further enhancing its reinforcing effect. The modified layer also forms a physical barrier, preventing water, oxygen, and other substances from contacting the glass fiber surface, thereby improving the performance stability of the composite material under humid and hot environments. However, excessive addition of modified glass fiber to the POM will significantly increase the material's rigidity, affecting not only its toughness but also its low-temperature stability. Therefore, the amount of modified glass fiber added should not exceed 15 parts.

[0017] Optionally, the method for preparing the temperature-resistant additive is as follows: S01: The intermediate is obtained by reacting N,N'-dimethyl-1,3-propanediamine and 2-chloro-N,N-dimethylethylamine. SO2: The intermediate and hydrogen peroxide are added to a solvent and reacted to obtain SO2.

[0018] Optionally, in step S01, the molar ratio of N,N'-dimethyl-1,3-propanediamine and 2-chloro-N,N-dimethylethylamine is 1:(2.4-2.8), the reaction temperature is 70-80℃, and the reaction time is 2-3h.

[0019] Optionally, the concentration of hydrogen peroxide in the hydrogen peroxide solution is 30%.

[0020] Optionally, in step S02, the molar ratio of the intermediate to hydrogen peroxide is 1:(2.1-2.4), the reaction temperature is 80-90℃, and the reaction time is 5-8h.

[0021] Specifically, the reaction formula for step S01 is as follows: .

[0022] Specifically, the reaction formula for step S02 is as follows: .

[0023] Optionally, the compatibilizer is a copolymer of glycidyl methacrylate and acrylic acid.

[0024] The epoxy and carboxyl groups in the copolymer of glycidyl methacrylate and acrylic acid can react with the amino groups or residual hydroxyl groups on the surface of modified glass fibers to form a cross-linked network. This network inhibits molecular chain migration, prevents local enrichment or vacancies, and forms a uniform and dense overall structure, reducing stress concentration and moisture permeation channels, thus further improving the material's temperature and moisture resistance. Simultaneously, the copolymer can improve the compatibility of temperature-resistant additives, ultrafine PTFE powder, and POM, solving the problem of stress concentration at the interface between these additives and POM.

[0025] Optionally, the compatibilizer is prepared by: Glycidyl methacrylate, acrylic acid, and an initiator are added to a solvent, and then the mixture is heated to 70-80℃ for 6-8 hours to polymerize. The product is then filtered, washed, and dried.

[0026] Optionally, the weight ratio of glycidyl methacrylate to acrylic acid is (1-1.5):1.

[0027] Within this weight ratio range, with a slight excess of acrylic acid, when copolymerized with glycidyl methacrylate, irregular block copolymers are formed. Because the epoxy groups present in glycidyl methacrylate have significant steric hindrance, they restrict the mobility of molecular chains. The formation of irregular block copolymers disperses these epoxy groups, while the linear, flexible segments of acrylic acid have less steric hindrance, increasing the contact opportunities between the copolymer and the modified glass fiber.

[0028] Optionally, the initiator is at least one of azobisisobutyronitrile, ammonium persulfate, and benzoyl peroxide.

[0029] Optionally, the lubricant is selected from at least one of stearic acid, zinc stearate, and calcium stearate.

[0030] Optionally, the antioxidant is selected from at least one of antioxidant 245, antioxidant 264, antioxidant 626, and antioxidant 1076.

[0031] Optionally, the filler is at least one of graphene and carbon nanotubes.

[0032] Optionally, the POM has a melt flow rate of 10-15 g / 10 min at 190°C and a load of 2.16 kg.

[0033] Optionally, the average particle size of the ultrafine polytetrafluoroethylene powder is 2-5 μm.

[0034] According to another aspect of this application, a method for preparing the temperature-resistant and moisture-resistant composite material for preparing bearing cages as described in any of the above claims is provided, comprising the following steps: (1) Mix 1 / 2 POM, 1 / 2 filler, heat-resistant additive, and compatibilizer and add them to a twin-screw extruder for extrusion granulation to obtain intermediate material A; (2) Mix 1 / 2 POM, 1 / 2 filler, ultrafine polytetrafluoroethylene powder, antioxidant and lubricant and then add them to a twin-screw extruder for extrusion granulation to obtain intermediate material B; (3) Mix intermediate material A and intermediate material B again and then add them to a twin-screw extruder for extrusion granulation to obtain the final product.

[0035] Because of the small particle size of ultrafine polytetrafluoroethylene powder, if it is directly mixed with POM, heat-resistant additives, etc., some ultrafine polytetrafluoroethylene powder will be coated by the heat-resistant additives and will be difficult to contact with POM, resulting in embrittlement of the composite material and fluctuation of the coefficient of friction. Therefore, this application selects a stepwise granulation process so that the composite material can simultaneously possess the heat resistance of the heat-resistant additives, the low friction and moisture resistance of ultrafine polytetrafluoroethylene powder, and the processing toughness of POM, thereby improving the performance stability and service life of the material under harsh environments.

[0036] Optionally, when adding modified glass fiber, the modified glass fiber is divided into two parts and added in steps (1) and (2) respectively.

[0037] Optionally, the extrusion temperature in step (1) is 210-220℃ and the rotation speed is 400-600rpm.

[0038] Optionally, the extrusion temperature in step (2) is 185-220℃ and the rotation speed is 400-600rpm.

[0039] Optionally, the extrusion temperature in step (3) is 190-225℃ and the rotation speed is 500-700 rpm.

[0040] The beneficial effects of this application include, but are not limited to: 1. The temperature- and moisture-resistant composite material for preparing bearing cages according to this application has excellent temperature and moisture resistance. It can maintain excellent dimensional stability and good mechanical properties in high temperature, low temperature or high humidity environments, and the bearing cages prepared from it can meet the requirements of long service life.

[0041] 2. The temperature-resistant and moisture-resistant composite material for preparing bearing cages according to this application improves the temperature resistance of the bearing cages prepared from the composite material by adding a temperature-resistant additive and utilizing the NO bond and carbonyl group contained in its molecular chain to block the depolymerization reaction of the POM matrix and reduce the thermo-oxidative degradation of the material at high temperature.

[0042] 3. The temperature- and moisture-resistant composite material for preparing bearing cages according to this application, by adding ultrafine polytetrafluoroethylene powder, whose molecular chain has no polar functional groups and whose fluorine atoms are closely arranged to form a hydrophobic protective layer, has excellent moisture resistance. Moreover, due to its wide operating temperature range, the temperature and moisture resistance of the composite material can be improved.

[0043] 4. According to the preparation method of the temperature-resistant and moisture-resistant composite material for preparing bearing cages in this application, the composite material is made to have the temperature resistance of the temperature-resistant additive, the low friction and moisture resistance of the ultrafine polytetrafluoroethylene powder, and the processing toughness of POM through a stepwise granulation process, thereby improving the performance stability and service life of the material under harsh environments. Detailed Implementation

[0044] The present application is described in detail below with reference to the embodiments, but the present application is not limited to these embodiments.

[0045] Unless otherwise specified, the raw materials used in the embodiments and comparative examples of this application were all purchased commercially.

[0046] Unless otherwise specified, the methods used in the embodiments and comparative examples of this application are conventional methods in the prior art. The control agents used in the following embodiments and comparative examples are all commercially available products, the average particle size of graphene is 5 μm, the average diameter of carbon nanotubes is 2 nm, and the average length is 5 μm.

[0047] Example 1 This embodiment relates to a temperature- and moisture-resistant composite material for preparing bearing cages, characterized in that, by weight, it comprises: 100 parts of POM, 20 parts of temperature-resistant additives, 5 parts of ultrafine polytetrafluoroethylene powder with an average particle size of 2 μm, 5 parts of graphene, 3 parts of compatibilizer, 0.5 parts of antioxidant 245, and 0.4 parts of stearic acid, wherein the melt flow rate of POM at 190°C and under a load of 2.16 kg is 10 g / 10 min.

[0048] The preparation method of this composite material includes the following steps: (1) Put 1 / 2 POM, 1 / 2 graphene, heat-resistant additives and compatibilizer powder into a mixer and stir it 3 times at a speed of 1500 rpm, each stirring time is 2 min. After stirring, add it to a twin-screw extruder for extrusion granulation to obtain intermediate material A. The extrusion temperature is 210℃ and the speed is 400 rpm. (2) Put 1 / 2 POM, 1 / 2 graphene, ultrafine polytetrafluoroethylene powder, antioxidant 245 and stearic acid into a mixer and stir 3 times at a speed of 1500 rpm for 2 minutes each time. After stirring, add it to a twin-screw extruder for extrusion granulation to obtain intermediate material B. The extrusion temperature is 185℃ and the speed is 400 rpm. (3) Put intermediate material A and intermediate material B into a mixer and stir them three times at a speed of 1500 rpm for 2 minutes each time. After stirring, add them to a twin-screw extruder for extrusion and granulation. The extrusion temperature is 190℃ and the speed is 500 rpm to obtain the composite material.

[0049] The preparation method of the temperature-resistant additive is as follows: S01: N,N'-dimethyl-1,3-propanediamine was dissolved in acetonitrile, and 2-chloro-N,N-dimethylethylamine, N,N'-dimethyl-1,3-propanediamine and 2-chloro-N,N-dimethylethylamine were added dropwise in a molar ratio of 1:2.8. Under N2 atmosphere protection, the mixture was stirred and heated to 80℃ for 2h to obtain an intermediate. The stirring speed was 150r / min. S02: Add the intermediate to isopropanol, heat to 90°C while stirring, add hydrogen peroxide with a concentration of 30% dropwise, the molar ratio of intermediate to hydrogen peroxide is 1:2.4, heat to 90°C for 5 hours under N2 atmosphere protection, cool after reaction to obtain heat-resistant additive, stirring speed is 150 r / min.

[0050] The preparation steps of the compatibilizer are as follows: Glycidyl methacrylate, acrylic acid, and azobisisobutyronitrile (0.5 wt% of total acrylic acid) in a weight ratio of 1:1 were added to DMF. The mixture was heated to 70°C and polymerized for 8 hours with stirring at a stirring speed of 150 r / min. After the reaction was completed, the mixture was cooled to room temperature, filtered, washed multiple times with DMF, and dried to obtain the final product.

[0051] Example 2 This embodiment relates to a temperature- and moisture-resistant composite material for preparing bearing cages, characterized in that, by weight, it comprises: 120 parts of POM, 10 parts of temperature-resistant additives, 8 parts of ultrafine polytetrafluoroethylene powder with an average particle size of 5 μm, 10 parts of carbon nanotubes, 10 parts of modified glass fiber, 4 parts of compatibilizer, 0.3 parts of antioxidant 264, and 0.2 parts of zinc stearate, wherein the melt flow rate of POM at 190°C and under a load of 2.16 kg is 15 g / 10 min.

[0052] The preparation method of this composite material includes the following steps: (1) Put 1 / 2 POM, 1 / 2 carbon nanotubes, 1 / 2 modified glass fiber, heat-resistant additives, and compatibilizer powder into a mixer and stir 3 times at a speed of 1500 rpm for 2 minutes each time. After stirring, add it to a twin-screw extruder for extrusion granulation to obtain intermediate material A. The extrusion temperature is 220℃ and the speed is 600 rpm. (2) 1 / 2 POM, 1 / 2 carbon nanotubes, 1 / 2 modified glass fiber, ultrafine polytetrafluoroethylene powder, antioxidant 264 and zinc stearate are put into a mixer and stirred 3 times at a speed of 1500 rpm for 2 minutes each time. After stirring, the mixture is added to a twin-screw extruder for extrusion granulation to obtain intermediate material B. The extrusion temperature is 220℃ and the speed is 600 rpm. (3) Put intermediate material A and intermediate material B into a mixer and stir 3 times at a speed of 1500 rpm for 2 minutes each time. After stirring, add them to a twin-screw extruder for extrusion and granulation. The extrusion temperature is 225℃ and the speed is 700 rpm to obtain the composite material.

[0053] The preparation steps of the modified glass fiber are as follows: S1 activates the glass fiber: the glass fiber is rinsed with deionized water 3 times, dried and then placed in a muffle furnace, heated to 450℃ at a rate of 5℃ / min and held for 3 hours, and then cooled to room temperature. S2 involves completely immersing the activated glass fiber in a 10wt% butyl carbamate solution, ultrasonically treating it at 40°C for 4 hours, and then removing and drying it to obtain the final product.

[0054] The preparation method of the temperature-resistant additive is as follows: S01: N,N'-dimethyl-1,3-propanediamine was dissolved in acetonitrile, and 2-chloro-N,N-dimethylethylamine, N,N'-dimethyl-1,3-propanediamine and 2-chloro-N,N-dimethylethylamine were added dropwise in a molar ratio of 1:2.4. Under N2 atmosphere protection, the mixture was stirred and heated to 70℃ for 3 h to obtain an intermediate. The stirring speed was 150 r / min. S02: Add the intermediate to isopropanol, heat to 80°C while stirring, add hydrogen peroxide with a concentration of 30% dropwise, the molar ratio of intermediate to hydrogen peroxide is 1:2.1, heat to 80°C under N2 atmosphere protection and react for 8 hours, cool after the reaction to obtain the heat-resistant additive, the stirring speed is 150 r / min.

[0055] The preparation steps of the compatibilizer are as follows: Glycidyl methacrylate, acrylic acid, and ammonium persulfate (0.6 wt% of total acrylic acid weight) in a weight ratio of 1.5:1 were added to DMF. The mixture was heated to 80°C and polymerized for 6 hours with stirring at a stirring speed of 150 r / min. After the reaction was completed, the mixture was cooled to room temperature, filtered, washed multiple times with DMF, and dried to obtain the final product.

[0056] Example 3 This embodiment relates to a temperature- and moisture-resistant composite material for preparing bearing cages, characterized in that, by weight, it comprises: 120 parts of POM, 12 parts of temperature-resistant additives, 6 parts of ultrafine polytetrafluoroethylene powder with an average particle size of 4 μm, 6 parts of graphene, 15 parts of modified glass fiber, 4 parts of compatibilizer, 0.4 parts of antioxidant 1076, and 0.3 parts of calcium stearate, wherein the melt flow rate of POM at 190°C and under a load of 2.16 kg is 15 g / 10 min.

[0057] The preparation method of this composite material includes the following steps: (1) Put 1 / 2 POM, 1 / 2 graphene, 1 / 2 modified glass fiber, heat-resistant additives, and compatibilizer powder into a mixer and stir it 3 times at a speed of 1500 rpm for 2 minutes each time. After stirring, add it to a twin-screw extruder for extrusion granulation to obtain intermediate material A. The extrusion temperature is 220℃ and the speed is 500 rpm. (2) 1 / 2 POM, 1 / 2 graphene, 1 / 2 modified glass fiber, ultrafine polytetrafluoroethylene powder, antioxidant 1076 and calcium stearate are put into a mixer and stirred 3 times at a speed of 1500 rpm for 2 minutes each time. After stirring, the mixture is added to a twin-screw extruder for extrusion granulation to obtain intermediate material B. The extrusion temperature is 210℃ and the speed is 500 rpm. (3) Put intermediate material A and intermediate material B into a mixer and stir them three times at a speed of 1500 rpm for 2 minutes each time. After stirring, add them to a twin-screw extruder for extrusion and granulation. The extrusion temperature is 210℃ and the speed is 600 rpm to obtain the composite material.

[0058] The preparation steps of the modified glass fiber are as follows: S1 activates the glass fiber: the glass fiber is rinsed with deionized water 3 times, dried and then placed in a muffle furnace, heated to 550℃ at a rate of 5℃ / min and held for 2 hours, and then cooled to room temperature. S2 involves completely immersing the activated glass fiber in a 15wt% butyl carbamate solution, ultrasonically treating it at 50°C for 2 hours, and then removing and drying it to obtain the final product.

[0059] The preparation method of the temperature-resistant additive is as follows: S01: N,N'-dimethyl-1,3-propanediamine was dissolved in acetonitrile, and 2-chloro-N,N-dimethylethylamine, N,N'-dimethyl-1,3-propanediamine and 2-chloro-N,N-dimethylethylamine were added dropwise in a molar ratio of 1:2.5. Under N2 atmosphere protection, the mixture was stirred and heated to 80℃ for 3h to obtain an intermediate. The stirring speed was 150r / min. S02: Add the intermediate to isopropanol, heat to 90°C while stirring, add hydrogen peroxide with a concentration of 30% dropwise, the molar ratio of intermediate to hydrogen peroxide is 1:2.3, heat to 90°C for 7 hours under N2 atmosphere protection, cool after reaction to obtain heat-resistant additive, stirring speed is 150 r / min.

[0060] The preparation steps of the compatibilizer are as follows: Glycidyl methacrylate, acrylic acid, and ammonium persulfate (0.4 wt% of the total weight of glycidyl methacrylate and acrylic acid) were added to DMF in a weight ratio of 1.3:1. The mixture was heated to 80°C and polymerized for 8 hours with stirring at a stirring speed of 150 r / min. After the reaction was completed, the mixture was cooled to room temperature, filtered, washed multiple times with DMF, and dried to obtain the final product.

[0061] Example 4 The difference between this embodiment and Example 3 is that the compatibilizer is commercially available polyethylene grafted maleic anhydride, which has a melt flow rate of 7 g / 10 min at 190°C and under a load of 2.16 kg. There is no compatibilizer preparation step, but all other steps are the same.

[0062] Example 5 The difference between this embodiment and Embodiment 3 is that unmodified glass fiber is used instead of modified glass fiber, and there is no preparation step for the unmodified glass fiber; all other aspects are the same.

[0063] Example 6 The difference between this embodiment and Embodiment 3 is that the modified glass fiber content is 18 parts, while the rest are the same.

[0064] Example 7 The difference between this embodiment and Embodiment 3 is that butyl formate is used instead of butyl carbamate; all other aspects are the same.

[0065] Example 8 The difference between this embodiment and Embodiment 3 is that the weight ratio of glycidyl methacrylate to acrylic acid is 0.9:1, while all other aspects are the same.

[0066] Example 9 The difference between this embodiment and Embodiment 3 is that the weight ratio of glycidyl methacrylate to acrylic acid is 1.6:1, while all other aspects are the same.

[0067] Comparative Example 1 The difference between this comparative example and Example 3 is that the temperature-resistant additive is 10 parts, while the rest are the same.

[0068] Comparative Example 2 The difference between this comparative example and Example 3 is that the temperature-resistant additive is 4 parts, while the rest are the same.

[0069] Comparative Example 3 The difference between this comparative example and Example 3 is that the amount of ultrafine polytetrafluoroethylene powder is 18 parts, while the rest are the same.

[0070] Comparative Example 4 The difference between this comparative example and Example 3 is that the amount of ultrafine polytetrafluoroethylene powder is 8 parts, while the rest are the same.

[0071] Comparative Example 5 The difference between this comparative example and Example 3 is that 2,6-di-tert-butyl-p-cresol is used instead of the heat-resistant additive, and there is no preparation step for the heat-resistant additive; all other aspects are the same.

[0072] Comparative Example 6 The difference between this comparative example and Example 3 is that polytetrafluoroethylene with a weight-average molecular weight of 800,000 and an average particle size of 30 μm is used instead of ultrafine polytetrafluoroethylene powder; all other aspects are the same.

[0073] Comparative Example 7 The difference between this comparative example and Example 3 is that step (1) involves putting all POM, all graphene, all modified glass fiber, heat-resistant additives, compatibilizer powder, ultrafine polytetrafluoroethylene powder, antioxidant 1076 and calcium stearate into a mixer, stirring 3 times at a speed of 1500 rpm, with each stirring time being 2 min. After stirring, the mixture is added to a twin-screw extruder for extrusion granulation to obtain the composite material. The extrusion temperature is 220℃ and the speed is 500 rpm. Steps (2) and (3) are omitted, while the rest are the same.

[0074] Test Example 1 The temperature- and moisture-resistant composite materials prepared in the above embodiments and comparative examples for manufacturing bearing cages were filled into cage molds. The cage molds containing the mixtures were then placed on a press for pre-compression, with the pre-compression pressure controlled at 500 kg / cm². 2 The holding time is controlled at 5 minutes. During the holding process, the upper and lower plates are locked together with bolts and nuts. The pressed and locked mold is then placed in a programmable sintering furnace. The mold is heated to 220°C within 40 minutes. When the temperature reaches 220°C, it is held for 30 minutes. After the holding time is completed, the mold is quickly removed and placed on a press for pressing, venting, and holding. The pressure is controlled at 1000 kg / cm². 2 After 5 minutes, stop holding the pressure and wait until the temperature of the cage mold is below 200℃ before demolding to obtain the bearing cage.

[0075] The mechanical properties of the obtained bearing protective frame were tested. The tensile strength was tested according to GB / T1040.2-2006, the bending strength was tested according to GB / T9341-2008, and the friction coefficient and wear amount were measured according to the standard GB / T3960-2016. The test was conducted in a 585K grease environment with a load of 20Kg and a speed of 400 revolutions per minute for 96 hours. The results are shown in Table 1.

[0076] Table 1

[0077] Test Example 2 The bearing protective frames prepared from the composite materials obtained in the above embodiments and comparative examples were stored at 80°C and +95% humidity for 1000 hours. The changes in length and dimensions were recorded, and mechanical properties were tested. Tensile strength was tested according to GB / T1040.2-2006, and flexural strength was tested according to GB / T9341-2008. The test results are shown in Table 2. The tensile strength reduction rate = (tensile strength before storage - tensile strength after storage) / tensile strength before storage × 100%, the flexural strength reduction rate = (flexural strength before storage - flexural strength after storage) / flexural strength before storage × 100%, and the dimensional change rate = |(dimensional change after storage - dimensional change before storage)| / dimensional change before storage × 100%.

[0078] Table 2

[0079] Test Example 3 The bearing protective frames prepared from the composite materials obtained in the above embodiments and comparative examples were stored at 110°C for 1000 hours. The changes in length dimensions were recorded, and mechanical properties were tested. Tensile strength was tested according to GB / T1040.2-2006, and flexural strength was tested according to GB / T9341-2008. The test results are shown in Table 3. The tensile strength reduction rate = (tensile strength before storage - tensile strength after storage) / tensile strength before storage × 100%, the flexural strength reduction rate = (flexural strength before storage - flexural strength after storage) / flexural strength before storage × 100%, and the dimensional change rate = |(dimensional change after storage - dimensional change before storage)| / dimensional change before storage × 100%. The bearing protective frame obtained in Comparative Example 7 broke directly during storage, so the data in the table is "-".

[0080] Table 3

[0081] The above description is merely an embodiment of this application, and the scope of protection of this application is not limited to these specific embodiments, but is determined by the claims of this application. Various modifications and variations can be made to this application by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the technical concept and principles of this application should be included within the scope of protection of this application.

Claims

1. A temperature and moisture resistant composite material for making a bearing cage, characterized in that, By weight parts, including: POM 100-120 parts, temperature resistant auxiliary 10-20 parts, ultra-fine polytetrafluoroethylene powder 5-8 parts, filler 5-10 parts, compatibility agent 3-4 parts, antioxidant 0.3-0.5 parts, lubricant 0.2-0.4 parts; The structural formula of the temperature resistant auxiliary is as follows: 。 2. The temperature and moisture resistant composite material for making a bearing cage according to claim 1, wherein, Further comprising modified glass fiber 10-15 parts, which is obtained by modifying butyl carbamate.

3. The temperature and moisture resistant composite material for making a bearing cage according to claim 2, wherein, The preparation method of the modified glass fiber is: S1, activating the glass fiber; S2, completely dipping the activated glass fiber in a butyl carbamate solution with a weight concentration of 10wt%-15wt%, ultrasonic treatment at 40-50℃ for 2-4h, taking out the modified glass fiber, drying, and obtaining.

4. The temperature resistant and moisture resistant composite material for preparing bearing retainer according to claim 1, wherein the preparation method of the temperature resistant auxiliary is: S01, reacting N, N'-dimethyl-1, 3-propanediamine and 2-chloro-N, N-dimethyl ethylamine to obtain an intermediate; S02, adding the intermediate and hydrogen peroxide into a solvent to obtain.

5. The temperature and moisture resistant composite material for making a bearing cage according to claim 1, wherein, The compatibility agent is a copolymer of glycidyl methacrylate and acrylic acid.

6. The temperature and moisture resistant composite material for making a bearing cage according to claim 4, wherein The preparation method of the compatibility agent is: Adding glycidyl methacrylate, acrylic acid, and initiator into a solvent, then heating to 70-80℃ for 6-8h of polymerization, filtering, washing, and drying to obtain.

7. The temperature and moisture resistant composite material for making a bearing cage according to claim 5, wherein The weight ratio of glycidyl methacrylate and acrylic acid is (1-1.5):

1.

8. The temperature and moisture resistant composite material for making a bearing cage according to claim 1, wherein, The melt flow rate of the POM at 190℃ under a load of 2.16kg is 10-15g / 10min. The average particle size of the ultra-fine polytetrafluoroethylene powder is 2-5μm.

9. The process for the production of temperature and humidity resistant composite material for the production of bearing cages according to any one of claims 1 to 8, characterized in that, Including the following steps: (1) mixing 1 / 2 POM, 1 / 2 filler, temperature resistant auxiliary, and compatibility agent, then adding into a double screw extruder for extrusion granulation to obtain intermediate A; (2) mixing 1 / 2 POM, 1 / 2 filler, ultra-fine polytetrafluoroethylene powder, antioxidant, and lubricant, then adding into a double screw extruder for extrusion granulation to obtain intermediate B; (3) mixing intermediate A and intermediate B again, then adding into a double screw extruder for extrusion granulation, and obtaining.

10. The method of claim 9, wherein, The extrusion temperature of step (1) is 210-220℃, and the rotation speed is 400-600rpm; The extrusion temperature of step (2) is 185-220℃, and the rotation speed is 400-600rpm; The extrusion temperature of step (3) is 190-225℃, and the rotation speed is 500-700rpm.

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