Refractory composite material for roller bracket and preparation method thereof

Abstract

The invention relates to the technical field of refractory materials, in particular to a refractory composite material for a roller support and a preparation method of the refractory composite material. The material comprises the following components: high-crystallinity co-polypropylene, a phosphorus-nitrogen-silicon ternary synergistic flame retardant, an expanded graphite-manganese series interlayer compound, mesoporous aluminum hydroxide, a ternary magnesium-aluminum-silicon layered composite material, temperature-responsive core-shell structure cerium oxide nanoparticles and the like. Through a multi-synergistic flame-retardant mechanism and a multi-scale structural design, excellent flame-retardant performance, mechanical performance and thermal stability are achieved, the material is particularly suitable for a roller support in a high-temperature industrial environment, and the problem that a traditional material is prone to failure in the high-temperature environment is solved.

Description

Technical Field

[0001] The invention relates to the technical field of refractory materials, and in particular to a refractory composite material for a roller bracket and a preparation method thereof. Background Art

[0002] With the development of industrial production, conveying equipment has been widely used in industries such as steel, electricity, petrochemicals, and mining. As a key component of conveying equipment, roller brackets often work in high-temperature, high-wear, and fire-hazardous environments. Traditional roller bracket materials are mainly metal and engineering plastics. Although metal materials have high heat resistance and mechanical strength, they have disadvantages such as large weight, high cost, and difficult installation and maintenance; engineering plastic materials such as polyamide and polycarbonate have light weight and good formability, but they are prone to softening and deformation in high temperature environments, and have poor fire resistance and flame retardancy, and are prone to rapid combustion and spread when a fire occurs.

[0003] At present, the flame-retardant modified polypropylene materials commonly used in the market are mainly modified by halogen flame retardants, phosphorus flame retardants or inorganic flame retardants. Although halogen flame retardants such as decabromodiphenyl ether have good flame retardant effects, they will release toxic gases when burned, causing harm to the environment and human health; although phosphorus flame retardants such as ammonium polyphosphate are environmentally friendly, they have low flame retardant efficiency when used alone, and are easy to absorb water, resulting in a decrease in the mechanical properties of the material; inorganic flame retardants such as magnesium hydroxide need to be added in large quantities to achieve the ideal flame retardant effect, but they seriously reduce the processing performance and mechanical properties of the material.

[0004] In the prior art, some studies have attempted to use a combination of multiple flame retardants to improve the flame retardant effect, such as CN118335405B, a fire-retardant cable and its preparation method. However, these solutions still have the following problems: First, it is difficult to balance the flame retardant effect and mechanical properties, and the increase in the amount of flame retardant added will lead to increased brittleness of the material; second, the long-term stability in high temperature environment is insufficient, and aging and cracking are prone to occur; third, there is a lack of a rapid response mechanism when a fire occurs, and it is impossible to effectively prevent the spread of the fire; fourth, the inorganic flame retardant filler has poor compatibility with the polypropylene matrix and uneven dispersion, resulting in large fluctuations in material properties.

[0005] Therefore, there is an urgent need to develop a refractory composite material for roller brackets that has both excellent flame retardant properties and mechanical properties and is suitable for high-temperature industrial environments to meet the requirements of modern industry for safe production. Summary of the invention

[0006] The purpose of the present invention is to provide a refractory composite material for a roller bracket and a preparation method thereof in view of the problems existing in the prior art. The material aims to solve the following technical problems: provide a refractory composite material with multiple synergistic flame retardant mechanisms, which can quickly form a dense carbon layer structure under fire conditions, effectively block oxygen and heat transfer, and thus achieve excellent flame retardant effect; provide a multi-scale structural system from nanometers, micrometers to macroscales, so that each component can work synergistically at different scales, ensuring excellent flame retardant performance without sacrificing the mechanical properties of the material; provide a refractory composite material with a temperature step response mechanism, which can gradually activate different protection mechanisms at different temperature stages to achieve synergistic protection over the entire temperature range; solve the problem of poor compatibility between inorganic flame retardant fillers and polypropylene matrix, improve component dispersion uniformity and interface bonding strength, and ensure the consistency and stability of material performance; provide a refractory composite material suitable for long-term stable use in high temperature environments above 200°C, meeting the use requirements of roller brackets in high temperature industrial environments such as steel, electricity, petrochemicals, and mining; provide an environmentally friendly flame retardant material that does not contain harmful elements such as halogens, releases less toxic gases during combustion, and meets the requirements of green and sustainable development of modern industry.

[0007] The object of the present invention is to provide a refractory composite material for a roller support, wherein the refractory composite material comprises, by weight: 100-150 parts by weight of high crystalline copolymer polypropylene; 15-35 parts by weight of a ternary synergistic flame retardant of phosphorus, nitrogen and silicon, wherein the ternary synergistic flame retardant of phosphorus, nitrogen and silicon comprises 7-18 parts by weight of a non-halogen phosphorus, nitrogen and flame retardant, 5-12 parts by weight of an amide-modified ammonium polyphosphate and 3-8 parts by weight of polysiloxane-modified nano-silica; 8-20 parts by weight of mesoporous aluminum hydroxide; 12-30 parts by weight of expanded graphite-manganese intercalation compound; 3-12 parts by weight of microencapsulated red phosphorus; 6-18 parts by weight of ternary magnesium-aluminum-silicon layered composite material; 4-12 parts by weight of temperature-responsive core-shell cerium oxide nanoparticles; 3-10 parts by weight of organosilicon-modified basalt fiber; 2-7 parts by weight of fused silica microfibers; 3-9 parts by weight of maleic anhydride grafted polypropylene compatibilizer; 2-6 parts by weight of phosphite auxiliary antioxidant; 1-4 parts by weight of modified montmorillonite nanosheets; 0.5-2.5 parts by weight of hindered amine light stabilizer and hindered phenol synergistic antioxidant system; 1-5 parts by weight of a polyacid catalytic carbonizing agent; 2-8 parts by weight of hollow glass microsphere phase change material composite; 0.5-3 parts by weight of lubricating additives.

[0008] Specifically, the preparation method of the expanded graphite-manganese intercalation compound comprises the following steps: Adding natural graphite sheets into a mixed solution of concentrated sulfuric acid and concentrated nitric acid to react, thereby obtaining an expanded graphite intermediate; The expanded graphite intermediate is added to an aqueous solution of manganese sulfate and potassium persulfate for ultrasonic dispersion, a sodium hydroxide solution is added dropwise to control the pH value, and then potassium permanganate is added for oxidation reaction; adding ascorbic acid to the reaction system to carry out a reduction reaction; The obtained product was subjected to supercritical CO 2 After the treatment, the product is heat treated under nitrogen protection and then impregnated with a glycidyl methacrylate solution to obtain an expanded graphite-manganese intercalation compound.

[0009] Specifically, the preparation method of the ternary magnesium-aluminum-silicon layered composite material comprises the following steps: Dissolving magnesium sulfate heptahydrate and aluminum sulfate 18hydrate in deionized water to obtain a metal salt solution, and dissolving sodium silicate in deionized water to obtain a sodium silicate solution; Under the condition of controlling the pH value, adding the sodium silicate solution dropwise into the metal salt solution to carry out a coprecipitation reaction; The coprecipitation system is hydrothermally treated at 160-180° C.; The product after hydrothermal treatment is intercalated with dodecyltrimethylammonium bromide; 3-aminopropyltriethoxysilane is added to the intercalation-modified dispersion for functionalization treatment to obtain a ternary magnesium-aluminum-silicon layered composite material.

[0010] Specifically, the method for preparing the temperature-responsive core-shell cerium oxide nanoparticles comprises the following steps: Cerium nitrate hexahydrate and citric acid solution are mixed and pH value is adjusted to prepare cerium core nanoparticles; dispersing the cerium core nanoparticles in an ethanol / water mixed solvent, and adding polyvinyl pyrrolidone as a dispersant; adding tetraethoxysilane and poly (N-isopropylacrylamide) solution dropwise into the dispersion to form a primary shell layer; Adding N-isopropylacrylamide monomer, methacrylic acid and N,N'-methylenebisacrylamide crosslinker to the primary shell dispersion, and initiating a polymerization reaction by ammonium persulfate to form a temperature-responsive shell; The surface of the obtained product is functionalized with a phosphodiester compound to obtain temperature-responsive core-shell structured cerium oxide nanoparticles.

[0011] Specifically, the method for preparing the hollow glass microsphere phase change material composite comprises the following steps: The surface of the hollow glass microspheres was treated with 3-aminopropyltriethoxysilane; The n-octadecane and stearic acid are melted and mixed, and butylated hydroxytoluene is added to obtain a phase change material mixture; Injecting the molten phase change material mixture into the surface-treated hollow glass microspheres under vacuum conditions; The filled microspheres are surface encapsulated with epoxy resin and polyamide curing agent; The encapsulated product is subjected to graded curing treatment to obtain a hollow glass microsphere phase change material composite.

[0012] The method for preparing the refractory composite material for the roller support comprises the following steps: (1) Multi-stage premixing: firstly, high crystalline copolymer polypropylene, maleic anhydride grafted polypropylene compatibilizer and hindered amine light stabilizer are mixed with hindered phenol synergistic antioxidant system; mesoporous aluminum hydroxide is mixed with ternary magnesium aluminum silicon layered composite material respectively, and then mixed with phosphite auxiliary antioxidant; organic silicon modified basalt fiber, fused quartz microfiber, modified montmorillonite nanosheet and polyacid catalytic carbonizing agent are mixed; after combining the above three mixtures, phosphorus nitrogen silicon ternary synergistic flame retardant is added; then expanded graphite-manganese intercalation compound and microencapsulated red phosphorus, as well as temperature-responsive core-shell structure cerium oxide nanoparticles, hollow glass microsphere phase change material composite and lubricating additive are added in sequence to obtain a premix; (2) Multi-stage reaction extrusion: the premix is ​​extruded in a twin-screw extruder, wherein the extruder is configured with nine temperature control zones, the temperature of the feed section is 160-170°C, the temperature of the first compression section is 180-190°C, the temperature of the first mixing section is 190-200°C, the temperature of the first reaction section is 200-210°C, the temperature of the second mixing section is 210-220°C, the temperature of the second reaction section is 215-225°C, the temperature of the second compression section is 205-215°C, the temperature of the homogenization section is 195-205°C, and the temperature of the head section is 185-195°C; (3) Hot pelletizing and tempering: The extruded material strips are water cooled and then hot pelletized, the pellets are dried, and then heat tempered under nitrogen protection to obtain refractory composite material particles; (4) Precision molding of roller bracket: The refractory composite material particles are used to prepare a roller bracket by precision injection molding technology, and then pre-treated and annealed to obtain the final product.

[0013] Specifically, the preparation method of the organosilicon-modified basalt fiber comprises the following steps: After drying the basalt fiber, the surface was degreased with acetone; The treated fibers are immersed in a mixed solution of hydrogen peroxide and concentrated sulfuric acid for surface activation; preparing a mixed silane coupling agent solution of γ-aminopropyltriethoxysilane and γ-methacryloxypropyltrimethoxysilane; Immersing the activated fiber in the silane coupling agent solution to perform a coupling reaction; The coupled fibers are dispersed in toluene, and decamethylcyclopentasiloxane and a platinum catalyst are added to perform polysiloxane encapsulation treatment to obtain organosilicon-modified basalt fibers.

[0014] Specifically, the multi-stage premixing process in step (1) is as follows: First, 100-150 parts by weight of high crystalline copolymer polypropylene, 3-9 parts by weight of maleic anhydride grafted polypropylene compatibilizer and 0.5-2.5 parts by weight of hindered amine light stabilizer and hindered phenol synergistic antioxidant system are premixed at 60-70° C. for 5-8 minutes at a mixing speed of 600-800 rpm; Mix 8-20 parts by weight of mesoporous aluminum hydroxide and 6-18 parts by weight of ternary magnesium aluminum silicon layered composite material, add 2-6 parts by weight of phosphite auxiliary antioxidant, and mix at 35-45° C. for 4-6 minutes; 3-10 parts by weight of organosilicon-modified basalt fibers, 2-7 parts by weight of fused silica microfibers, 1-4 parts by weight of modified montmorillonite nanosheets, and 1-5 parts by weight of a polyacid catalytic carbonizing agent are mixed by low-speed stirring for 3-5 minutes; Add the obtained inorganic filler mixture and fiber composite system to the base mixture, mix for 6-8 minutes at 55-65°C and a mixing speed of 500-700rpm, then add 15-35 parts by weight of phosphorus nitrogen silicon ternary synergistic flame retardant, and continue mixing for 4-6 minutes; Add 12-30 parts by weight of expanded graphite-manganese intercalation compound and 3-12 parts by weight of microencapsulated red phosphorus, mix at 50-60° C. for 5-7 minutes at a mixing speed of 400-600 rpm; 4-12 parts by weight of temperature-responsive core-shell cerium oxide nanoparticles, 2-8 parts by weight of hollow glass microsphere phase change material composite and 0.5-3 parts by weight of lubricating additive are added, and finally mixed at 45-55° C. for 6-8 minutes at a mixing speed of 300-500 rpm.

[0015] Specifically, in the multi-stage reaction extrusion process in step (2), the screw speed is set to: 80-100 rpm in the front section, 100-120 rpm in the middle section, and 70-90 rpm in the rear section; the melt residence time is controlled at 2.5-3.5 minutes; a negative pressure exhaust device is installed in the first reaction section, and the pressure is controlled at -0.08 to -0.1 MPa.

[0016] Specifically, the precision forming process of the roller bracket in step (4) is as follows: The tempered particles obtained in step (3) are used to prepare a roller bracket by precision injection molding technology, the injection molding machine adopts a multi-point gate design, and the barrel temperature is set to 210-220° C., 215-225° C., 220-230° C., and 215-225° C. from back to front; Mold temperature zoning control: cavity area 45-55℃, runner area 60-70℃; The injection pressure is set to: 90-100MPa in the first stage and 70-80MPa in the second stage; The injection speed is controlled by five stages of gradual change: 10%, 30%, 60%, 40%, 20%; The holding time is set to 18-25 seconds, and the holding pressure is 60-70MPa; The cooling time is 35-45 seconds, and the in-mold cooling adopts variable temperature technology; Pre-treat the formed roller bracket at 90-100°C for 0.5-1 hour to release internal stress; Under nitrogen protection, anneal at 130-150°C for 1.5-2.5 hours; The mixture was cooled to room temperature at a rate of 5-8°C / min to obtain the final product.

[0017] The refractory composite material for roller bracket and the preparation method thereof of the present invention achieve the following beneficial effects through innovative material design and fine process control: 1. Excellent flame retardant performance: Through the synergistic effect of phosphorus-nitrogen-silicon ternary synergistic flame retardant and expanded graphite-manganese intercalation compound, a "physical barrier-chemical blocking-thermal stability enhancement" trinity multiple fire retardant mechanism is formed, making the material oxygen index as high as 38-43%, and the UL 94 test reaches V-0 level, which is far superior to traditional flame retardant materials. Under the direct action of high-temperature flames, the material can quickly form a dense carbon layer, and the back temperature rise is only 72-85℃, which is 40-60% lower than the comparison material, effectively preventing the spread of fire.

[0018] 2. Excellent mechanical properties: Through the multi-scale structural design of components such as silicone-modified basalt fiber and fused quartz microfiber, the problem of "flame retardancy and mechanical properties are difficult to balance" in traditional flame-retardant materials has been solved. The material has a tensile strength of 40-44MPa, a flexural strength of 65-73MPa, and an impact strength of 21-24kJ / m², which is 20-60% higher than traditional flame-retardant PP materials and meets the mechanical load requirements in industrial environments.

[0019] 3. Excellent thermal stability: The material's heat deformation temperature (HDT) reaches 132-142°C, the thermal decomposition starting temperature (T5%) reaches 318-335°C, and the carbon residue rate at 600°C reaches 36-42%, which is 30-100% higher than the comparative material. This high thermal stability enables the material to be used stably in high temperature environments above 200°C, meeting the needs of harsh industrial environments.

[0020] 4. Excellent interfacial compatibility: Through the precise design of the compatibility system such as maleic anhydride grafted polypropylene compatibilizer and phosphite auxiliary antioxidant, the problem of poor compatibility between inorganic fillers and polypropylene matrix is ​​solved, and the uniform dispersion and strong interfacial bonding of each component are achieved, ensuring the consistency and stability of material performance.

[0021] 5. Excellent long-term performance: After aging at 120°C for 1,000 hours, the material's strength retention rate still reaches 87-92%. It performs well in high-temperature simulated use environment tests, and its service life is more than three times that of traditional materials, significantly reducing equipment maintenance costs and downtime risks.

[0022] 6. Good environmental performance: The material does not contain harmful elements such as halogens, releases less toxic gases during combustion, and has low smoke density, which meets the requirements of modern industry for environmental protection and safety.

[0023] 7. Excellent comprehensive application performance: The material has good wear resistance, electrical insulation and dimensional stability, and performs well in high-temperature and high-risk industrial environments such as steel, electricity, petrochemicals, and mining. It has been successfully used in the conveying equipment of many companies and has achieved significant economic and social benefits. DETAILED DESCRIPTION

[0024] The technical scheme of the present invention will be clearly and completely described below in conjunction with specific embodiments. Based on the embodiments in the present invention, all other embodiments obtained by ordinary technicians in the field without creative work are within the scope of protection of the present invention. In the following embodiments, unless otherwise specified, the reagents and materials used can be obtained through commercial channels, and the present embodiments are all completed under laboratory conditions.

[0025] The invention provides a fire-resistant composite material for a roller support and a preparation method thereof. The invention is further described in detail below in conjunction with examples, but the protection scope of the invention is not limited thereto. Example

[0026] The fire-resistant composite material provided in this embodiment comprises, by weight: 100 parts by weight of high crystalline copolymer polypropylene (Borstar® RC068M, Borealis); 15 parts by weight of a ternary synergistic flame retardant of phosphorus, nitrogen and silicon, wherein the ternary synergistic flame retardant of phosphorus, nitrogen and silicon comprises 7 parts by weight of a non-halogen phosphorus, nitrogen and nitrogen flame retardant (Exolit® OP 1230 or cyclotriphosphazene phenolate, Clariant), 5 parts by weight of an amide-modified ammonium polyphosphate (Exolit® AP 765, Clariant) and 3 parts by weight of polysiloxane-modified nano-silica (Aerosil® R8200, Evonik); 8 parts by weight of a mesoporous aluminum hydroxide (Apyral® 40CD, Nabtesco); 12 parts by weight of an expanded graphite-manganese intercalation compound; 3 parts by weight of microencapsulated red phosphorus (Exolit® RP 6520, Clariant); 6 parts by weight of ternary magnesium aluminum silicon layered composite material; 4 parts by weight of temperature-responsive core-shell cerium oxide nanoparticles; 3 parts by weight of silicone-modified basalt fiber; 2 parts by weight of fused silica microfiber (Quartzel® microfiber, Saint-Gobain); 3 parts by weight of maleic anhydride grafted polypropylene compatibilizer (Exxelor™ PO1020, ExxonMobil); 2 parts by weight of phosphite auxiliary antioxidant (Doverphos S-9228, Clariant); 1 part by weight of modified montmorillonite nanosheet (Cloisite® 30B, BYK); 0.5 parts by weight of hindered amine light stabilizer and hindered phenol synergistic antioxidant system, including 0.3 parts by weight of pentaerythritol tetrakis[β-(3,5-di-tert-butyl-4-hydroxyphenyl) propionate (Irganox 1010, BASF) and 0.2 parts by weight of bis(2,2,6,6-tetramethyl-4-piperidinyl) sebacate (Tinuvin 770, BASF); 1 part by weight of a polyacid catalyzed carbonizer (ammonium phosphotungstate, Sigma-Aldrich); 2 parts by weight of a hollow glass microsphere phase change material composite; and 0.5 parts by weight of a lubricating additive (Vanlube® 622 or Molyvan® L or Vanlube 7723, Vanderbilt).

[0027] The preparation method of expanded graphite-manganese intercalation compound is as follows: Step A1: Preparation of expanded graphite matrix 30 parts by weight of natural graphite flakes (purity 99.5%, flake diameter 50 μm, thickness 5 μm) were added to a mixed solution of 80 parts by weight of concentrated sulfuric acid (concentration 98%) and 5 parts by weight of concentrated nitric acid (concentration 65%), and stirred at 30°C for 15 hours at a stirring speed of 200 rpm. The reaction product was diluted with deionized water, centrifuged (3000 rpm, 10 minutes), and washed with deionized water until neutral. The washed product was dried at 70°C for 12 hours to obtain an expanded graphite intermediate.

[0028] Step A2: Intercalation of manganese compounds 10 parts by weight of manganese sulfate (MnSO 4 ·H 2 O) and 5 parts by weight of potassium persulfate (K 2 S 2 O 8 ) was dissolved in 100 parts by weight of deionized water. 20 parts by weight of the expanded graphite intermediate obtained in step A1 was added to the above solution and ultrasonically dispersed at 60° C. (power 500 W) for 30 minutes. 8 parts by weight of sodium hydroxide solution (concentration 30%) was added dropwise to the dispersion, the pH value was controlled at 9.5, and the reaction was continued with stirring for 2 hours.

[0029] Step A3: In situ redox reaction Add 5 parts by weight of potassium permanganate (KMnO 4 ), stirred and reacted at 70°C for 3 hours, and the redox potential was controlled within 400 mV. 2 parts by weight of ascorbic acid (vitamin C) were added to the reaction system for slow reduction, the pH value was controlled at 7.5, and stirred and reacted for 1 hour.

[0030] Step A4: Supercritical CO 2 deal with The product obtained in step A3 was filtered and washed with deionized water and ethanol three times each. The washed product was placed in a supercritical CO 2 In a fluid device, the mixture was treated at 40°C and 10 MPa for 1 hour, and the pressure was slowly reduced (0.3 MPa / min) to normal pressure to take out the product.

[0031] Step A5: Surface activation The product obtained in step A4 was heat treated at 400°C for 0.5 hours under nitrogen protection. After cooling to room temperature, it was immersed in 3 parts by weight of acetone solution of glycidyl methacrylate (GMA) (concentration 10%) for 20 minutes. It was filtered and vacuum dried at 50°C for 8 hours to obtain an expanded graphite-manganese intercalation compound.

[0032] The preparation method of the ternary magnesium-aluminum-silicon layered composite material is as follows: Step B1: Precursor solution preparation 30 parts by weight of magnesium sulfate heptahydrate (MgSO 4 7H 2 O) and 15 parts by weight of aluminum sulfate octahydrate (Al 2 (SO 4 ) 3 18H 2 O) was dissolved in 150 parts by weight of deionized water and stirred at 50°C for 20 minutes to obtain a metal salt solution. 2 SiO3 9H 2 O) was dissolved in 80 parts by weight of deionized water, stirred and dissolved to obtain a sodium silicate solution.

[0033] Step B2: Coprecipitation reaction At 35°C, the sodium silicate solution was added to the metal salt solution at a rate of 3 mL / min, while stirring (speed 500 rpm), and the pH value was controlled within the range of 10.0 (adjusted with 20% sodium hydroxide solution). After the addition was completed, stirring was continued for 40 minutes to form a coprecipitation system.

[0034] Step B3: Hydrothermal crystallization The coprecipitation system obtained in step B2 was transferred to a hydrothermal reactor and hydrothermally treated at 160° C. for 6 hours, with the pressure maintained at 1.8 MPa. The mixture was naturally cooled to room temperature and the product was taken out.

[0035] Step B4: Intercalation modification The product obtained in step B3 was centrifuged (4000 rpm, 15 minutes), washed with deionized water for 3 times, the washed precipitate was dispersed in 80 parts by weight of deionized water, 5 parts by weight of dodecyltrimethylammonium bromide (DTAB) was added as an intercalation agent, and stirred at 65° C. for 8 hours.

[0036] Step B5: Functionalization Add 3 parts by weight of 3-aminopropyltriethoxysilane (APTES) to the dispersion obtained in step B4, and stir the reaction at 70°C for 4 hours. Centrifuge the reaction product and wash it 3 times with deionized water and ethanol respectively. Dry the product at 80°C for 12 hours, and then post-treat it at 120°C for 2 hours. Grind the dried product and pass it through an 80-mesh sieve to obtain a ternary magnesium-aluminum-silicon layered composite material.

[0037] The preparation method of temperature-responsive core-shell cerium oxide nanoparticles is as follows: Step C1: Cerium core preparation 12 parts by weight of cerium nitrate hexahydrate (Ce(NO 3 ) 3 6H 2 Dissolve 60 parts by weight of citric acid (C 6 H 8 O 7 ) was dissolved in 25 parts by weight of deionized water, added dropwise to the cerium nitrate solution, and stirred for 40 minutes. 12 parts by weight of 25% ammonia (NH 3 ·H 2 O), control the pH at 8.5 and stir for 1.5 hours.

[0038] Step C2: Core particle formation The solution obtained in step C1 was heated and stirred at 75°C for 4 hours while passing a small amount of O 2 (flow rate 5 mL / min). The reaction system was cooled to room temperature and centrifuged (8000 rpm, 25 minutes). The mixture was washed with deionized water and anhydrous ethanol for 3 times each to obtain cerium core nanoparticles.

[0039] Step C3: Temperature responsive shell construction The cerium core nanoparticles obtained in step C2 are dispersed in 50 parts by weight of an ethanol / water mixed solvent (volume ratio 7:3). Add 2 parts by weight of polyvinyl pyrrolidone (PVP, K30) as a dispersant and ultrasonically disperse (power 400W) for 20 minutes. Under nitrogen protection, 5 parts by weight of an ethanol solution of tetraethoxysilane (TEOS) (concentration 20%) are slowly added to the dispersion. Add 0.5 parts by weight of an aqueous solution of poly N-isopropylacrylamide (PNIPAM) (concentration 5%). Stir the reaction at 30°C for 8 hours to form a primary shell layer.

[0040] Step C4: Temperature response function loading To the dispersion obtained in step C3, 1 part by weight of N-isopropylacrylamide (NIPAM) monomer, 0.1 part by weight of methacrylic acid (MAA) and 0.05 part by weight of N,N'-methylenebisacrylamide (MBA) crosslinker were added. Nitrogen was passed through to deoxygenate for 20 minutes, and 0.03 part by weight of ammonium persulfate (APS) initiator was added. The reaction was carried out at 50°C for 4 hours to form a temperature-responsive shell layer.

[0041] Step C5: Post-processing and functionalization The product obtained in step C4 was centrifuged (10000rpm, 30 minutes). It was washed with deionized water and ethanol 4 times each, and vacuum dried at 50°C for 10 hours. The dried product was dispersed in 10 parts by weight of tetrahydrofuran (THF). 1 part by weight of a phosphate diester compound (bis(2-ethylhexyl) hydrogen phosphate) was added for surface functionalization, and the reaction was stirred at 40°C for 3 hours. Centrifugation, washing with ethanol 3 times, and vacuum dried at 60°C for 12 hours to obtain temperature-responsive core-shell cerium oxide nanoparticles.

[0042] The preparation method of organosilicon modified basalt fiber is as follows: Step D1: Fiber pretreatment 25 parts by weight of basalt fiber (average diameter 9 μm, length 3 mm) was placed in a vacuum oven and vacuum dried at 130°C for 3 hours. The dried fiber was placed in 50 parts by weight of acetone and ultrasonically treated (power 300 W) for 15 minutes for surface degreasing. The fiber was separated by filtration and dried at 100°C for 2 hours.

[0043] Step D2: Surface activation The fiber treated in step D1 was immersed in 20 parts by weight of 30% hydrogen peroxide solution (H 2 O 2 ) and 5 parts by weight of concentrated sulfuric acid (H 2 SO 4 ) in a mixed solution (volume ratio 4:1). Treat at 40°C for 30 minutes to introduce hydroxyl active sites. Filter, wash with deionized water until neutral, and dry at 90°C for 3 hours.

[0044] Step D3: Preparation of silane coupling agent solution Mix 8 parts by weight of γ-aminopropyltriethoxysilane (KH-550) and 3 parts by weight of γ-methacryloxypropyltrimethoxysilane (KH-570). Dissolve the mixture in 90 parts by weight of anhydrous ethanol. Add 0.8 parts by weight of glacial acetic acid to adjust the pH to 4.0. Stir and hydrolyze at room temperature for 1.5 hours to form a silane coupling agent solution.

[0045] Step D4: Silane coupling modification The activated fiber obtained in step D2 was immersed in the silane coupling agent solution prepared in step D3, and ultrasonically treated at 35°C (power 350W) for 30 minutes, and stirred at 60°C for 2 hours to allow the silane coupling agent to be fully grafted onto the fiber surface.

[0046] Step D5: Polysiloxane encapsulation The modified fiber obtained in step D4 was filtered and separated, and washed three times with anhydrous ethanol. The washed fiber was dispersed in 80 parts by weight of toluene. 5 parts by weight of decamethylcyclopentasiloxane (D5) and 0.5 parts by weight of platinum catalyst (Kaster catalyst, concentration is 2%) were added. Reflux reaction was carried out at 80°C for 3 hours to form a polysiloxane encapsulation layer. Filter and wash twice with toluene and ethanol respectively. Dry at 100°C for 4 hours, and then post-treat at 150°C for 1 hour to obtain silicone-modified basalt fiber.

[0047] The preparation method of the hollow glass microsphere phase change material composite is as follows: Step E1: Pretreatment of hollow glass microspheres 20 parts by weight of hollow glass microspheres (K20 type, average particle size 45 μm, wall thickness 0.5 μm, true density 0.18 g / cm³) were placed in a vacuum oven and vacuum dried at 120°C for 4 hours. The dried microspheres were placed in 5 parts by weight of a toluene solution of 3-aminopropyltriethoxysilane (APTES) (concentration 10%) and stirred at 50°C for 2 hours. Filtered, washed twice with toluene and ethanol, and dried at 80°C for 3 hours.

[0048] Step E2: Phase change material preparation 15 parts by weight of n-octadecane (C18 H 38 ) and 5 parts by weight of stearic acid (C 18 H 36 O 2 ) were melted and mixed at 70° C. 0.5 parts by weight of butylated hydroxytoluene (BHT) was added as an antioxidant. The mixture was stirred evenly and cooled to 60° C. to obtain a phase change material mixture.

[0049] Step E3: Filling by negative pressure osmosis Place the hollow glass microspheres treated in step E1 in a vacuum container and evacuate to 0.01 MPa. Under vacuum conditions, slowly inject the molten phase change material mixture obtained in step E2 (maintained at 65°C) into the container to completely cover the microspheres. Maintain the vacuum conditions and maintain the temperature for 1 hour to allow the phase change material to fully penetrate into the microspheres. Slowly restore normal pressure and maintain the temperature for 30 minutes.

[0050] Step E4: Surface Mounting The filled microspheres obtained in step E3 were separated by filtration and quickly washed twice with 60°C n-hexane to remove excess phase change material on the surface. The washed microspheres were dispersed in 40 parts by weight of ethyl acetate. 3 parts by weight of epoxy resin (bisphenol A type) and 1 part by weight of polyamide curing agent were added. Stir at 45°C for 2 hours to form an encapsulation layer.

[0051] Step E5: Curing and post-processing The product obtained in step E4 was filtered and separated, placed in an oven, and pre-cured at 60°C for 4 hours. The temperature was raised to 120°C, and post-cured for 2 hours. The product was cooled to room temperature, ground through a 100-mesh sieve, and a hollow glass microsphere phase change material composite was obtained.

[0052] The preparation method of the refractory composite material is as follows: Step (1): Multi-stage premixing First, 100 parts by weight of high crystalline copolymer polypropylene, 3 parts by weight of maleic anhydride grafted polypropylene compatibilizer and 0.5 parts by weight of hindered amine light stabilizer and hindered phenol synergistic antioxidant system were placed in a high-speed mixer and pre-mixed at 60°C for 5 minutes at a mixing speed of 600rpm. 8 parts by weight of mesoporous aluminum hydroxide and 6 parts by weight of ternary magnesium aluminum silicon layered composite materials were mixed, and 2 parts by weight of phosphite auxiliary antioxidant were added, and mixed at 35°C for 4 minutes to make the surface uniformly coated. 3 parts by weight of organosilicon modified basalt fiber, 2 parts by weight of fused quartz microfiber, 1 part by weight of modified montmorillonite nanosheet and 1 part by weight of polyacid catalytic carbonizer were mixed, and low-speed stirring (200rpm) was used for 3 minutes to avoid fiber breakage. After combining the above three mixtures, 15 parts by weight of phosphorus nitrogen silicon ternary synergistic flame retardant were added, and mixed at 55°C for 6 minutes at a mixing speed of 500rpm. Then, 12 parts by weight of expanded graphite-manganese intercalation compound and 3 parts by weight of microencapsulated red phosphorus were added, mixed at 50° C. for 5 minutes at a mixing speed of 400 rpm. Finally, 4 parts by weight of temperature-responsive core-shell cerium oxide nanoparticles, 2 parts by weight of hollow glass microsphere phase change material composites and 0.5 parts by weight of lubricating additives were added, and finally mixed at 45° C. for 6 minutes at a mixing speed of 300 rpm to obtain a premix.

[0053] Step (2): Multi-stage reactive extrusion The premix obtained in step (1) is transferred to a co-rotating co-rotating twin-screw extruder, and the extruder is set to nine temperature control zones, the temperature of the feed section is 160°C, the temperature of the first compression section is 180°C, the temperature of the first mixing section is 190°C, the temperature of the first reaction section is 200°C (equipped with a negative pressure exhaust device, the pressure is controlled at -0.08MPa), the temperature of the second mixing section is 210°C, the temperature of the second reaction section is 215°C, the temperature of the second compression section is 205°C, the temperature of the homogenization section is 195°C, and the temperature of the head section is 185°C. The screw speed is set to: 80rpm for the front section, 100rpm for the middle section, and 70rpm for the rear section, and the melt residence time is controlled at 2.5 minutes.

[0054] Step (3): Hot pelletizing and tempering The extruded material strips were water cooled and then hot pelletized. The pellets were vacuum dried at 85°C for 5 hours, and the moisture content was controlled at ≤0.05%. Under nitrogen protection, the pellets were heat-tempered at 110°C for 1.5 hours to improve the crystallinity and obtain refractory composite material pellets.

[0055] Step (4): Precision molding of the roller bracket The tempered particles obtained in step (3) are used to prepare a roller bracket using precision injection molding technology. The injection molding machine adopts a multi-point gate design, and the barrel temperature is set to 210°C, 215°C, 220°C, and 215°C from back to front; the mold temperature is controlled by zone: 45°C in the cavity area and 60°C in the runner area; the injection pressure is set to: 90MPa in the first stage and 70MPa in the second stage; the injection speed is controlled by five-stage gradual change: 10%, 30%, 60%, 40%, and 20%; the holding time is set to 18 seconds, and the holding pressure is 60MPa; the cooling time is 35 seconds, and the in-mold cooling adopts variable temperature technology. The molded roller bracket is pretreated at 90°C for 0.5 hours to release the internal stress. Under nitrogen protection, annealing treatment is performed at 130°C for 1.5 hours. Cool to room temperature at a rate of 5°C / min to obtain the final product. Example

[0056] The fire-resistant composite material provided in this embodiment comprises, by weight: 150 parts by weight of high crystalline copolymer polypropylene (Borstar® RC068M, Borealis); 35 parts by weight of a ternary synergistic flame retardant of phosphorus, nitrogen and silicon, wherein the ternary synergistic flame retardant of phosphorus, nitrogen and silicon comprises 18 parts by weight of a non-halogen phosphorus, nitrogen and nitrogen flame retardant (Exolit® OP 1230 or cyclotriphosphazene phenolate, Clariant), 12 parts by weight of an amide-modified ammonium polyphosphate (Exolit® AP 765, Clariant) and 8 parts by weight of polysiloxane-modified nano-silica (Aerosil® R8200, Evonik); 20 parts by weight of mesoporous aluminum hydroxide (Apyral® 40CD, Nabtesco); 30 parts by weight of an expanded graphite-manganese intercalation compound; 12 parts by weight of microencapsulated red phosphorus (Exolit® RP 6520, Clariant); 18 parts by weight of ternary magnesium aluminum silicon layered composite material; 12 parts by weight of temperature-responsive core-shell cerium oxide nanoparticles; 10 parts by weight of silicone-modified basalt fiber; 7 parts by weight of fused silica microfiber (Quartzel® microfiber, Saint-Gobain); 9 parts by weight of maleic anhydride grafted polypropylene compatibilizer (Exxelor™ PO1020, ExxonMobil); 6 parts by weight of phosphite auxiliary antioxidant (Doverphos S-9228, Clariant); 4 parts by weight of modified montmorillonite nanosheets (Cloisite® 30B, BYK); 2.5 parts by weight of hindered amine light stabilizer and hindered phenol synergistic antioxidant system, including 1.5 parts by weight of pentaerythritol tetrakis[β-(3,5-di-tert-butyl-4-hydroxyphenyl) propionate (Irganox 1010, BASF) and 1.0 parts by weight of bis(2,2,6,6-tetramethyl-4-piperidinyl) sebacate (Tinuvin 770, BASF); 5 parts by weight of polyacid catalytic carbonizing agent (ammonium phosphotungstate, Sigma-Aldrich); 8 parts by weight of hollow glass microsphere phase change material composite; 3 parts by weight of lubricating additive (Vanlube® 622 or Molyvan® L or Vanlube 7723, Vanderbilt).

[0057] The preparation method of expanded graphite-manganese intercalation compound is as follows: In this embodiment, the preparation method of expanded graphite-manganese intercalation compound is basically the same as that in Example 1, but with the following parameter adjustments: Step A1: Use 40 parts by weight of natural graphite sheets (purity 99.5%, sheet diameter 80 μm, thickness 10 μm), 100 parts by weight of concentrated sulfuric acid and 10 parts by weight of concentrated nitric acid, stir and react at 40°C for 25 hours at a stirring speed of 300 rpm.

[0058] Step A2: Use 15 parts by weight of manganese sulfate and 8 parts by weight of potassium persulfate, 120 parts by weight of deionized water, and 30 parts by weight of expanded graphite intermediate, ultrasonically disperse (power 600 W) at 70° C. for 45 minutes, add 12 parts by weight of sodium hydroxide solution, control the pH value at 10.5, and stir the reaction for 3 hours.

[0059] The other parameters in steps A3 to A5 are adjusted to the upper limit values ​​in the range accordingly. In particular, in the surface activation treatment step, heat treatment is performed at 450°C for 1 hour, immersion treatment is performed using 5 parts by weight of an acetone solution of glycidyl methacrylate (concentration 15%) for 30 minutes, and vacuum drying is performed at 60°C for 12 hours.

[0060] The preparation method of the ternary magnesium-aluminum-silicon layered composite material is as follows: In this embodiment, the preparation method of the ternary magnesium-aluminum-silicon layered composite material is basically the same as that in Embodiment 1, but with the following parameter adjustments: Step B1: 40 parts by weight of magnesium sulfate heptahydrate, 20 parts by weight of aluminum sulfate 18hydrate, 180 parts by weight of deionized water, 25 parts by weight of sodium silicate and 100 parts by weight of deionized water were used.

[0061] Step B2: at 45°C, the dropping speed was 5 mL / min, the stirring speed was 700 rpm, and the pH value was controlled at 11.0.

[0062] Step B3: Hydrothermal treatment at 180°C for 8 hours, maintaining the pressure at 2.2 MPa.

[0063] The other parameters in steps B4 to B5 are adjusted to the upper limit values ​​within the range accordingly, including using 8 parts by weight of dodecyltrimethylammonium bromide, stirring and reacting at 75°C for 10 hours, using 5 parts by weight of 3-aminopropyltriethoxysilane for functionalization treatment, stirring and reacting at 80°C for 6 hours, drying at 90°C for 16 hours, post-treating at 130°C for 3 hours, and passing through a 100-mesh sieve after grinding.

[0064] The preparation method of the refractory composite material is as follows: Steps (1) to (4) are substantially the same as those in Example 1, except that the amounts of all components are adjusted to the above-mentioned parts by weight, and the temperature parameters and time parameters are adjusted to the upper limit values. In particular, in the multi-stage reaction extrusion of step (2), the pressure of the first reaction stage is controlled to be -0.1 MPa, the screw speed is increased to 100 rpm in the front section, 120 rpm in the middle section, and 90 rpm in the rear section, and the melt residence time is extended to 3.5 minutes. In the final molding process, the holding time is extended to 25 seconds, the holding pressure is increased to 70 MPa, and the cooling time is extended to 45 seconds. The annealing temperature is increased to 150°C, the time is extended to 2.5 hours, and the cooling rate is adjusted to 8°C / min. Example

[0065] The fire-resistant composite material provided in this embodiment includes, by weight: 125 parts by weight of high-crystalline copolymer polypropylene; 25 parts by weight of phosphorus-nitrogen-silicon ternary synergistic flame retardant, including 13 parts by weight of non-halogen phosphorus-nitrogen flame retardant, 8 parts by weight of amide-modified ammonium polyphosphate and 5 parts by weight of polysiloxane-modified nano-silicon dioxide; 15 parts by weight of mesoporous aluminum hydroxide; 20 parts by weight of expanded graphite-manganese intercalation compound; 7 parts by weight of microencapsulated red phosphorus; 12 parts by weight of ternary magnesium-aluminum-silicon layered composite material; 8 parts by weight of temperature-responsive core-shell structured cerium oxide nanoparticles; 6 parts by weight of organosilicon-modified basalt fiber; 4 parts by weight of fused quartz microfiber; 6 parts by weight of maleic anhydride grafted polypropylene compatibilizer; 4 parts by weight of phosphite auxiliary antioxidant; 2.5 parts by weight of modified montmorillonite nanosheets; 1.5 parts by weight of hindered amine light stabilizer and hindered phenol synergistic antioxidant system; 3 parts by weight of polyacid catalytic carbonizing agent; 5 parts by weight of hollow glass microsphere phase change material composite; and 2 parts by weight of lubricating additive.

[0066] The preparation method of expanded graphite-manganese intercalation compound is as follows: In this embodiment, the preparation of expanded graphite-manganese intercalation compound adopts the intermediate parameter values ​​of embodiment 1 and embodiment 2: Step A1: Use 35 parts by weight of natural graphite sheets (purity 99.5%, sheet diameter 65 μm, thickness 8 μm), 90 parts by weight of concentrated sulfuric acid and 8 parts by weight of concentrated nitric acid, stir and react at 35°C for 20 hours at a stirring speed of 250 rpm.

[0067] Step A2: Use 12.5 parts by weight of manganese sulfate and 6.5 parts by weight of potassium persulfate, 110 parts by weight of deionized water, and 25 parts by weight of expanded graphite intermediate, ultrasonically disperse (power 550 W) at 65° C. for 38 minutes, add 10 parts by weight of sodium hydroxide solution, control the pH value at 10.0, and stir the reaction for 2.5 hours.

[0068] Step A3: Add 6.5 parts by weight of potassium permanganate to the reaction system, stir and react at 72.5° C. for 3.5 hours, and control the redox potential within the range of 425 mV. Add 3 parts by weight of ascorbic acid to the reaction system, control the pH value at 8.0, and stir and react for 1.5 hours.

[0069] Step A4: Supercritical CO 2 The treatment was carried out at 42.5°C and 11 MPa for 1.25 hours, with a pressure reduction rate of 0.4 MPa / min.

[0070] Step A5: heat treatment at 425° C. for 0.75 hours, immersion treatment with 4 parts by weight of acetone solution of glycidyl methacrylate (concentration 12.5%) for 25 minutes, and vacuum drying at 55° C. for 10 hours.

[0071] Preparation method of ternary magnesium-aluminum-silicon layered composite material In this embodiment, the preparation parameters of the ternary magnesium-aluminum-silicon layered composite material are set at the middle value of the range: Step B1: 35 parts by weight of magnesium sulfate heptahydrate, 17.5 parts by weight of aluminum sulfate 18hydrate, 165 parts by weight of deionized water, 22.5 parts by weight of sodium silicate and 90 parts by weight of deionized water were used.

[0072] Step B2: at 40°C, the dropping speed was 4 mL / min, the stirring speed was 600 rpm, and the pH value was controlled at 10.5.

[0073] Step B3: Hydrothermal treatment at 170°C for 7 hours, maintaining the pressure at 2.0 MPa.

[0074] Step B4: 6.5 parts by weight of dodecyltrimethylammonium bromide was used and stirred for reaction at 70° C. for 9 hours.

[0075] Step B5: Use 4 parts by weight of 3-aminopropyltriethoxysilane, stir and react at 75°C for 5 hours, dry at 85°C for 14 hours, post-treat at 125°C for 2.5 hours, grind and pass through a 90-mesh sieve.

[0076] The preparation method of temperature-responsive core-shell cerium oxide nanoparticles is as follows In this embodiment, the preparation of temperature-responsive core-shell cerium oxide nanoparticles adopts intermediate parameter values: Step C1: Use 15 parts by weight of cerium nitrate hexahydrate, 70 parts by weight of deionized water, 8 parts by weight of citric acid, 30 parts by weight of deionized water, and 15 parts by weight of 25% ammonia water, control the pH at 9.0, and stir for 2 hours.

[0077] Step C2: Heat and stir at 80°C for 5 hours, and introduce O 2 The flow rate was 7.5 mL / min, and the mixture was centrifuged (9000 rpm, 30 minutes).

[0078] Step C3: Use 60 parts by weight of ethanol / water mixed solvent, 3 parts by weight of polyvinyl pyrrolidone, ultrasonic dispersion (power 450 W) for 25 minutes, 6.5 parts by weight of tetraethoxysilane ethanol solution, 0.75 parts by weight of poly (N-isopropylacrylamide) aqueous solution, and stir the reaction at 32.5°C for 9 hours.

[0079] Steps C4 to C5 use intermediate parameter values, including 1.5 parts by weight of N-isopropylacrylamide monomer, 0.2 parts by weight of methacrylic acid, 0.1 parts by weight of a cross-linking agent, 0.045 parts by weight of an initiator, a reaction temperature of 52.5°C, a time of 5 hours, centrifugation parameters (11000 rpm, 35 minutes), a drying temperature of 55°C, a time of 11 hours, functionalization using 1.5 parts by weight of a phosphodiester compound, a reaction temperature of 45°C, a time of 3.5 hours, and a final drying temperature of 65°C, a time of 13.5 hours.

[0080] The preparation method of organosilicon modified basalt fiber is as follows: In this embodiment, the preparation of organosilicon-modified basalt fiber adopts intermediate parameter values: Step D1: Use 30 parts by weight of basalt fiber (average diameter 11 μm, length 4.5 mm), vacuum dry at 140°C for 4 hours, 60 parts by weight of acetone, ultrasonic treatment (power 350 W) for 20 minutes, drying temperature 110°C, time 2.5 hours.

[0081] Step D2: using a mixed solution of 25 parts by weight of a 30% hydrogen peroxide solution and 7.5 parts by weight of concentrated sulfuric acid, the treatment temperature is 45° C., the time is 38 minutes, and the drying temperature is 95° C., the time is 3.5 hours.

[0082] Steps D3 to D5 use intermediate parameter values, including adjusting the mixing ratio of the silane coupling agent to 10:4, using 100 parts by weight of anhydrous ethanol, 1.0 parts by weight of glacial acetic acid, pH value 4.5, hydrolysis time 2 hours, ultrasonic treatment temperature 40°C, power 400W, time 35 minutes, reaction temperature 65°C, time 2.5 hours, using 90 parts by weight of toluene, 6.5 parts by weight of decamethylcyclopentasiloxane, 0.75 parts by weight of platinum catalyst, reflux temperature 85°C, time 3.5 hours, drying parameters (110°C, 5 hours), and post-treatment (160°C, 1.5 hours).

[0083] Preparation method of hollow glass microsphere phase change material composite In this embodiment, the preparation of the hollow glass microsphere phase change material composite adopts the intermediate parameter value: Step E1: Use 25 parts by weight of hollow glass microspheres (average particle size 55 μm, wall thickness 0.75 μm, true density 0.2 g / cm³), vacuum drying at 130°C for 5 hours, 6.5 parts by weight of toluene solution of 3-aminopropyltriethoxysilane (concentration 10%), treatment temperature 55°C, time 2.5 hours, drying temperature 85°C, time 3.5 hours.

[0084] Steps E2 to E5 use intermediate parameter values, including using 17.5 parts by weight of n-octadecane, 6.5 parts by weight of stearic acid, 0.75 parts by weight of antioxidant, melting temperature 75°C, cooling to 62.5°C, vacuum degree 0.03MPa, infiltration temperature 67.5°C, time 1.5 hours, post-treatment temperature 37.5 minutes, washing 2.5 times with 62.5°C n-hexane, 45 parts by weight of ethyl acetate, 4 parts by weight of epoxy resin, 1.5 parts by weight of curing agent, reaction temperature 50°C, time 2.5 hours, pre-curing (65°C, 5 hours), post-curing (130°C, 2.5 hours), and passing through a 110-mesh sieve.

[0085] Preparation method of refractory composite material Step (1): Multi-stage premixing 125 parts by weight of high crystalline copolymer polypropylene, 6 parts by weight of maleic anhydride grafted polypropylene compatibilizer and 1.5 parts by weight of hindered amine light stabilizer and hindered phenol synergistic antioxidant system were placed in a high-speed mixer and pre-mixed at 65°C for 6.5 minutes at a mixing speed of 700rpm. 15 parts by weight of mesoporous aluminum hydroxide and 12 parts by weight of ternary magnesium aluminum silicon layered composite materials were mixed, 4 parts by weight of phosphite auxiliary antioxidant were added, and mixed at 40°C for 5 minutes. 6 parts by weight of organosilicon modified basalt fiber, 4 parts by weight of fused quartz microfiber, 2.5 parts by weight of modified montmorillonite nanosheets and 3 parts by weight of polyacid catalytic carbonizer were mixed and stirred at low speed (250rpm) for 4 minutes. After combining the above three mixtures, 25 parts by weight of phosphorus nitrogen silicon ternary synergistic flame retardant were added, mixed at 60°C for 7 minutes, and the mixing speed was 600rpm. Then, 20 parts by weight of expanded graphite-manganese intercalation compound and 7 parts by weight of microencapsulated red phosphorus were added, mixed at 55°C for 6 minutes at a mixing speed of 500 rpm. Finally, 8 parts by weight of temperature-responsive core-shell cerium oxide nanoparticles, 5 parts by weight of hollow glass microsphere phase change material composite and 2 parts by weight of lubricating additive were added, and finally mixed at 50°C for 7 minutes at a mixing speed of 400 rpm.

[0086] The parameters of step (2) to step (4) are set at the middle values ​​of their respective ranges, and the equipment configuration and process flow are basically the same as those in Example 1. Example

[0087] The fire-resistant composite material provided in this embodiment focuses on optimizing the synergistic effect of the phosphorus-nitrogen-silicon ternary synergistic flame retardant system and the expanded graphite-manganese intercalation compound. The formula comprises, by weight: 120 parts by weight of high-crystalline copolymer polypropylene; 30 parts by weight of phosphorus-nitrogen-silicon ternary synergistic flame retardant, including 15 parts by weight of non-halogen phosphorus-nitrogen flame retardant, 10 parts by weight of amide-modified ammonium polyphosphate and 5 parts by weight of polysiloxane-modified nano-silicon dioxide; 12 parts by weight of mesoporous aluminum hydroxide; 25 parts by weight of expanded graphite-manganese intercalation compound; 5 parts by weight of microencapsulated red phosphorus; 10 parts by weight of ternary magnesium-aluminum-silicon layered composite material; 6 parts by weight of temperature-responsive core-shell structured cerium oxide nanoparticles; 8 parts by weight of organosilicon-modified basalt fiber; 5 parts by weight of fused quartz microfiber; 5 parts by weight of maleic anhydride grafted polypropylene compatibilizer; 3 parts by weight of phosphite auxiliary antioxidant; 2 parts by weight of modified montmorillonite nanosheets; 1 part by weight of hindered amine light stabilizer and hindered phenol synergistic antioxidant system; 4 parts by weight of polyacid catalytic carbonizing agent; 4 parts by weight of hollow glass microsphere phase change material composite; and 1 part by weight of lubricating additive.

[0088] The preparation method of expanded graphite-manganese intercalation compound is as follows: In this embodiment, the preparation of expanded graphite-manganese intercalation compound particularly emphasizes the control of redox reaction: Step A1: 35 parts by weight of natural graphite sheets, 90 parts by weight of concentrated sulfuric acid and 7 parts by weight of concentrated nitric acid were used, and the mixture was stirred at 38° C. for 22 hours at a stirring speed of 280 rpm.

[0089] Step A2: Use 13 parts by weight of manganese sulfate and 7 parts by weight of potassium persulfate, 115 parts by weight of deionized water, and 28 parts by weight of expanded graphite intermediate, ultrasonically disperse (power 580 W) at 68° C. for 40 minutes, add 10 parts by weight of sodium hydroxide solution, control the pH value at 10.2, and stir the reaction for 2.8 hours.

[0090] Step A3: A total of 7 parts by weight of potassium permanganate was added to the reaction system in three times, each time with an interval of 30 minutes, and the reaction was stirred at 75°C for 3.8 hours, and the redox potential was accurately controlled within the range of 430±5mV. 2.8 parts by weight of ascorbic acid solution (concentration 15%) was slowly added dropwise to the reaction system, the pH value was controlled at 8.2, and the reaction was stirred for 1.8 hours.

[0091] Step A4: Supercritical CO 2 The treatment was carried out at 43°C and 11.5 MPa for 1.3 hours, and the pressure reduction rate was precisely controlled at 0.38 MPa / min.

[0092] Step A5: heat treatment at 430° C. for 0.8 hours, immersion treatment with 4.5 parts by weight of acetone solution of glycidyl methacrylate (concentration 12%) for 28 minutes, and vacuum drying at 58° C. for 11 hours.

[0093] The preparation method of the refractory composite material is as follows: Parameter settings of steps (1) to (4) In order to optimize the synergistic effect of the phosphorus-nitrogen-silicon ternary synergistic flame retardant and the expanded graphite-manganese intercalation compound, the mixing order in step (1) is specially adjusted: the phosphorus-nitrogen-silicon ternary synergistic flame retardant and the expanded graphite-manganese intercalation compound are first pre-mixed at 50°C for 5 minutes to allow the two components to fully contact, and then mixed with other components. During the extrusion process of step (2), the temperature of the first reaction stage is adjusted to 205°C, and the temperature of the second reaction stage is adjusted to 220°C to promote the interaction between the phosphorus-nitrogen compound and the graphite intercalation compound. Example

[0094] The fire-resistant composite material provided in this embodiment focuses on optimizing the synergistic effect of the high-temperature enhancement system. The formula includes, by weight: 130 parts by weight of high-crystalline copolymer polypropylene; 20 parts by weight of phosphorus-nitrogen-silicon ternary synergistic flame retardant; 10 parts by weight of mesoporous aluminum hydroxide; 18 parts by weight of expanded graphite-manganese intercalation compound; 4 parts by weight of microencapsulated red phosphorus; 15 parts by weight of ternary magnesium-aluminum-silicon layered composite material; 10 parts by weight of temperature-responsive core-shell structure cerium oxide nanoparticles; 9 parts by weight of organosilicon-modified basalt fiber; 6 parts by weight of fused quartz microfiber; 7 parts by weight of maleic anhydride grafted polypropylene compatibilizer; 5 parts by weight of phosphite auxiliary antioxidant; 3 parts by weight of modified montmorillonite nanosheets; 2 parts by weight of hindered amine light stabilizer and hindered phenol synergistic antioxidant system; 2 parts by weight of polyacid catalytic carbonizer; 6 parts by weight of hollow glass microsphere phase change material composite; 2 parts by weight of lubricating additive.

[0095] The preparation method of the ternary magnesium-aluminum-silicon layered composite material is as follows: In this embodiment, the preparation of the ternary magnesium-aluminum-silicon layered composite material particularly emphasizes the precise control of the hydrothermal crystallization process: Step B1: 38 parts by weight of magnesium sulfate heptahydrate, 19 parts by weight of aluminum sulfate 18hydrate, 170 parts by weight of deionized water, 23 parts by weight of sodium silicate and 95 parts by weight of deionized water were used to adjust the molar ratio of metal salt to silicate to 1.2:1:0.8 (Mg:Al:Si).

[0096] Step B2: At 42°C, the dropping speed was controlled in a sawtooth wave form (average 4.2 mL / min), the stirring speed was 650 rpm, and the pH value was precisely controlled at 10.8±0.2.

[0097] Step B3: adopt programmed temperature hydrothermal crystallization method, first maintain at 150°C for 2 hours, then increase the temperature to 175°C at a heating rate of 1°C / min and maintain for 5 hours, maintaining the pressure at 2.0±0.1MPa.

[0098] Step B4: 7 parts by weight of dodecyltrimethylammonium bromide was added in two portions and stirred at 72° C. for 9.5 hours. Ultrasonic treatment was performed for 15 minutes every 2 hours to promote intercalation.

[0099] Step B5: Use 4.5 parts by weight of 3-aminopropyltriethoxysilane, dilute it with an ethanol / water mixed solvent (volume ratio 3:1) and add it dropwise, stir and react at 76°C for 5.5 hours, dry at 85°C for 15 hours, post-treat at 128°C for 2.8 hours, grind and pass through a 85-mesh sieve.

[0100] The preparation method of temperature-responsive core-shell cerium oxide nanoparticles is as follows: In this embodiment, the preparation of temperature-responsive core-shell cerium oxide nanoparticles particularly emphasizes the control of the temperature-responsive shell layer: Steps C1 to C2 are substantially the same as those in Example 3, but are adjusted to: Step C3: Disperse using 65 parts by weight of ethanol / water mixed solvent (volume ratio 8:2), 3.5 parts by weight of polyvinyl pyrrolidone, add 0.5 parts by weight of polyethylene glycol (PEG-2000) as a co-dispersant, ultrasonic dispersion (power 460 W) for 28 minutes, and slowly add 6.8 parts by weight of tetraethoxysilane ethanol solution to the dispersion at a nitrogen flow rate of 30 mL / min. At the same time, add 0.8 parts by weight of an aqueous solution of poly (N-isopropylacrylamide) and polyacrylic acid (PAA) copolymer (weight ratio 8:2), and stir the reaction at 33°C for 9.5 hours.

[0101] Step C4: Add 1.8 parts by weight of N-isopropylacrylamide monomer, 0.4 parts by weight of methacrylic acid, 0.2 parts by weight of N,N'-methylenebisacrylamide crosslinker and 0.1 parts by weight of acrylamide (AM) to the dispersion obtained in step C3. Use cooling-heating cycle deoxygenation method (first deoxygenate at 5°C for 15 minutes, then deoxygenate at 35°C for 15 minutes, and cycle twice), add 0.05 parts by weight of ammonium persulfate initiator. Carry out under temperature graded polymerization conditions (first react at 48°C for 2 hours, then react at 55°C for 3 hours).

[0102] Step C5: Post-treatment and functionalization: The sample was washed with deionized water and ethanol 4 times, vacuum dried at 52°C for 6 hours, and then dispersed in 12 parts by weight of tetrahydrofuran. First, 0.5 parts by weight of octadecylamine (C18H37NH2) was added for pretreatment for 1 hour, and then 1.8 parts by weight of phosphodiester compound was added and stirred at 43°C for 4 hours. After centrifugation, the sample was washed 4 times with ethanol / acetone mixed solvent (volume ratio 2:1), and treated under gradient drying conditions (first at 50°C for 4 hours, then dried at 68°C for 10 hours).

[0103] Preparation method of refractory composite material: In this embodiment, the multi-stage reaction extrusion process of step (2) is specially adjusted, and a special screw combination design is adopted. From the feed end to the discharge end, a conveying section-crushing section-mixing section-conveying section-reaction section-exhaust section-compression section-mixing section-conveying section is arranged in sequence, and reverse thread elements are arranged at key positions to enhance the shear mixing effect. The screw speed is designed to be 85-95rpm in the front section, 105-115rpm in the middle section, and 75-85rpm in the rear section, and a pulse speed control is adopted (speed change once every 30 seconds). The melt residence time is precisely controlled at 3.0±0.2 minutes. Example

[0104] The fire-resistant composite material provided in this embodiment focuses on optimizing the synergistic effect of the compatibility and synergistic system. The formula includes, by weight: 115 parts by weight of high-crystalline copolymer polypropylene; 22 parts by weight of phosphorus-nitrogen-silicon ternary synergistic flame retardant; 16 parts by weight of mesoporous aluminum hydroxide; 16 parts by weight of expanded graphite-manganese intercalation compound; 6 parts by weight of microencapsulated red phosphorus; 9 parts by weight of ternary magnesium-aluminum-silicon layered composite material; 7 parts by weight of temperature-responsive core-shell structure cerium oxide nanoparticles; 5 parts by weight of organosilicon-modified basalt fiber; 3 parts by weight of fused quartz microfiber; 8 parts by weight of maleic anhydride grafted polypropylene compatibilizer; 5.5 parts by weight of phosphite auxiliary antioxidant; 3.5 parts by weight of modified montmorillonite nanosheets; 2.2 parts by weight of hindered amine light stabilizer and hindered phenol synergistic antioxidant system; 2.5 parts by weight of polyacid catalytic carbonizer; 5 parts by weight of hollow glass microsphere phase change material composite; 2.5 parts by weight of lubricating additive.

[0105] The preparation method of organosilicon modified basalt fiber is as follows: In this embodiment, the preparation of organosilicon-modified basalt fiber particularly emphasizes the effectiveness of surface modification: Step D1: 27 parts by weight of basalt fiber (average diameter 10 μm, length 4 mm) was first vacuum dried at 145°C for 4.5 hours, and then ultrasonically treated with a mixed solution of 55 parts by weight of acetone and 5 parts by weight of cyclohexane (volume ratio 9:1) (power 330 W) for 18 minutes for surface degreasing. The fiber was separated by filtration and dried at 105°C for 2.3 hours.

[0106] Step D2: Using a two-step surface activation method, the treated fiber was first immersed in 22 parts by weight of a 30% hydrogen peroxide solution for pretreatment for 15 minutes, and then 6.5 parts by weight of concentrated sulfuric acid was added (slowly added dropwise) and treated at 42°C for 35 minutes. Filtered, washed with deionized water until neutral, then neutralized with 0.5% sodium bicarbonate solution for 10 minutes, and finally washed with deionized water until neutral, and dried at 92°C for 3.2 hours.

[0107] Step D3: The silane coupling agent solution adopts a three-component design, and 9 parts by weight of γ-aminopropyl triethoxysilane, 3.5 parts by weight of γ-methacryloxypropyl trimethoxysilane and 1 part by weight of γ-mercaptopropyl trimethoxysilane are mixed. The mixture is dissolved in 95 parts by weight of anhydrous ethanol. 0.9 parts by weight of glacial acetic acid is added to adjust the pH to 4.2. Pre-hydrolyze at 28°C for 1 hour, then heat to 35°C and continue hydrolysis for 1 hour to form a silane coupling agent solution.

[0108] Step D4: The activated fiber obtained in step D2 is immersed in the silane coupling agent solution prepared in step D3. The ultrasonic-stirring alternating treatment method is adopted, that is, ultrasonic treatment (power 380W) is first performed at 38°C for 15 minutes, then stirred for 15 minutes, and then ultrasonic treatment for 15 minutes, and the cycle is repeated 3 times. Then, the reaction is stirred at 65°C for 2.3 hours, and finally the temperature is raised to 75°C for reaction for 30 minutes, so that the silane coupling agent is fully grafted to the fiber surface.

[0109] Step D5: A double-layer packaging design is adopted. After washing with anhydrous ethanol for 3 times, the modified fiber is dispersed in 85 parts by weight of toluene. 5.5 parts by weight of decamethylcyclopentasiloxane and 0.6 parts by weight of platinum catalyst are added, and the first layer of packaging is formed by reflux reaction at 83°C for 3.2 hours. After filtering, it is dispersed in 40 parts by weight of toluene, and 2 parts by weight of vinyl polysiloxane (Vi-PDMS, viscosity 500cSt) and 0.3 parts by weight of platinum catalyst are added, and the second layer of packaging is formed by reaction at 90°C for 1.5 hours. Filter, wash with toluene and ethanol twice each. Using the gradient drying method, first dry at 80°C for 2 hours, then dry at 105°C for 3 hours, and finally post-treat at 155°C for 1.2 hours to obtain silicone-modified basalt fiber.

[0110] The preparation method of the hollow glass microsphere phase change material composite is as follows: In this embodiment, the preparation of the hollow glass microsphere phase change material composite particularly emphasizes the composition optimization of the phase change material: Step E1: 22 parts by weight of special hollow glass microspheres (K25 type, average particle size 50 μm, wall thickness 0.65 μm, true density 0.19 g / cm³) were selected, first vacuum dried at 125°C for 4.5 hours, then treated with a mixed solution of 5.5 parts by weight of 3-aminopropyltriethoxysilane and 1 part by weight of N-β-(aminoethyl)-γ-aminopropyltrimethoxysilane (total concentration 12%, solvent toluene / ethanol = 3:1), stirred at 52°C for 2.2 hours. Filtered, washed twice with toluene and ethanol, and dried at 82°C for 3.2 hours.

[0111] Step E2: The phase change material adopts a ternary composite design, and 16 parts by weight of n-octadecane, 4 parts by weight of paraffin (melting point 52-54°C) and 6 parts by weight of stearic acid are melted and mixed at 72°C. 0.65 parts by weight of butylated hydroxytoluene and 0.2 parts by weight of di-tert-butyl-p-cresol are added as a composite antioxidant system. Stir evenly and cool to 61°C to obtain a phase change material mixture.

[0112] Steps E3-E5: Negative pressure penetration adopts a cyclic pressure method, that is, maintain a vacuum degree of 0.02MPa for 30 minutes, then restore to 0.05MPa for 10 minutes, and then drop to 0.02MPa, and cycle 3 times to make the phase change material more evenly penetrate into the microspheres. The surface encapsulation adopts an epoxy / phenolic composite system, using 3.5 parts by weight of epoxy resin, 0.8 parts by weight of phenolic resin and 1.3 parts by weight of modified polyamide curing agent. The curing adopts a three-step method, first pre-curing at 60°C for 3 hours, then curing at 90°C for 1 hour, and finally post-curing at 130°C for 1.5 hours.

[0113] The preparation method of the refractory composite material is as follows: The preparation method of this embodiment particularly emphasizes the synergistic effect of the compatibility and synergistic system: Step (1): In the multi-stage premixing, the maleic anhydride grafted polypropylene compatibilizer, phosphite auxiliary antioxidant, modified montmorillonite nanosheets and hindered amine light stabilizer are first premixed with the hindered phenol synergistic antioxidant system at 58°C for 4 minutes to form a "super compatibilizer" system, and then mixed with high crystalline copolymer polypropylene to ensure that the compatibilizer system is fully combined with the matrix. Before adding the inorganic filler, the mixture is rapidly melt-mixed at 180°C for 2 minutes and then cooled to 60°C to form a more stable compatible matrix.

[0114] The parameters of steps (2) to (4) are substantially the same as those of Example 5, but in the precision molding of the roller bracket in step (4), a double injection molding process is adopted, that is, the outer layer material (the formulation of the present invention) is injected first, and then the inner layer material (reinforced PP) is injected, to form a roller bracket with a gradient structure, wherein the outer layer provides excellent fire retardant properties, and the inner layer provides good mechanical performance support.

[0115] Through the detailed description of the above embodiments, it can be seen that the fire-resistant composite material for roller brackets of the present invention and the preparation method thereof have significant innovation and technical effects. The material solves the problem that traditional roller bracket materials are easy to fail under high temperature environment through the three-in-one multiple fire retardant mechanism of "physical barrier-chemical blocking-thermal stability enhancement". In particular, the synergistic effect of the phosphorus nitrogen silicon ternary synergistic flame retardant and the expanded graphite-manganese intercalation compound can quickly form a dense carbon layer under the action of flame, effectively blocking oxygen and heat transfer; while the temperature-responsive core-shell structure cerium oxide nanoparticles release active substances at dangerous temperatures to catalyze the formation of a more stable carbon layer structure. The ternary magnesium aluminum silicon layered composite material and the hollow glass microsphere phase change material composite provide effective thermal management functions, respectively delaying the temperature rise by releasing crystal water and phase change endothermic absorption. The silicone-modified basalt fiber and the fused quartz microfiber provide structural support at high temperatures to ensure that the material can still maintain shape stability at high temperatures.

[0116] The material of the present invention solves the problem of poor compatibility between inorganic components and PP matrix through a carefully designed compatibility and synergistic system, and achieves a synergistic improvement of excellent mechanical properties and flame retardant properties. At the same time, the preparation method of the present invention adopts a multi-stage premixing and precisely controlled reaction extrusion process to ensure that each component is evenly distributed on a microscopic scale and fully exerts a synergistic effect. This refractory composite material is particularly suitable for roller brackets of conveying equipment in high-temperature and high-risk industrial environments such as steel, electricity, petrochemicals, and mining, which significantly improves the safety, reliability, and service life of the equipment.

[0117] In order to verify the performance advantages of the refractory composite material of the present invention, the following comparative examples were designed for comparative testing.

[0118] Comparative Example 1 Comparative Example 1 uses a conventional flame-retardant polypropylene formula, which includes, by weight: 100 parts by weight of polypropylene (MFI=8g / 10min); 30 parts by weight of brominated flame retardant (decabromodiphenyl ether, FR-1210, Changting Chemical); 5 parts by weight of antimony trioxide (Sb2O3, synergist); 3 parts by weight of PE wax (lubricant); 0.5 parts by weight of antioxidant 1010 (Irganox 1010, BASF). A conventional single-screw extruder is used for processing, the temperature is set at 170-210°C, the screw speed is 60rpm, and then injection molding is used to prepare a roller bracket sample.

[0119] Comparative Example 2 Comparative Example 2 uses a phosphorus-based flame-retardant polypropylene formula, but does not include the synergistic flame-retardant system of the present invention, and includes, by weight: 100 parts by weight of polypropylene; 25 parts by weight of ammonium polyphosphate (APP, Exolit AP422, Clariant); 5 parts by weight of pentaerythritol (PER); 8 parts by weight of magnesium hydroxide (MDH); 3 parts by weight of maleic anhydride grafted polypropylene (PP-g-MAH); 2 parts by weight of PE wax; 0.5 parts by weight of antioxidant 1010. A conventional twin-screw extruder was used for processing, the temperature was set to 180-220°C, the screw speed was 80rpm, and then injection molding was used to prepare a roller bracket sample.

[0120] Comparative Example 3 Comparative Example 3 contains some innovative components of the present invention, but lacks the key synergistic mechanism, and includes, by weight: 100 parts by weight of high crystalline copolymer polypropylene; 15 parts by weight of non-halogen phosphorus and nitrogen flame retardant; 10 parts by weight of expanded graphite (without manganese modification); 10 parts by weight of aluminum hydroxide (without mesoporous treatment); 5 parts by weight of red phosphorus (without microencapsulation); 5 parts by weight of basalt fiber (without silicone modification); 3 parts by weight of maleic anhydride grafted polypropylene compatibilizer; 1 part by weight of antioxidant 1010. A preparation method similar to that of Example 1 is adopted, but the multi-stage premixing process is lacking, and all components are directly added to the extruder at one time for mixed extrusion.

[0121] Comparative Example 4 Comparative Example 4 uses some components of the present invention, but the preparation method is different, and includes, by weight: 100 parts by weight of high crystalline copolymer polypropylene; 15 parts by weight of phosphorus nitrogen silicon ternary synergistic flame retardant; 10 parts by weight of expanded graphite-manganese intercalation compound; 8 parts by weight of mesoporous aluminum hydroxide; 5 parts by weight of organosilicon modified basalt fiber; 3 parts by weight of maleic anhydride grafted polypropylene compatibilizer; 1 part by weight of antioxidant 1010. The preparation method does not use a multi-stage reaction extrusion process, but uses a traditional one-step mixing extrusion, the extruder temperature is set to a uniform 200°C, and the screw speed is constant at 70rpm.

[0122] Performance Testing Methods 1. Flame retardant performance test 1.1 Oxygen Index (LOI) Test The test was conducted in accordance with GB / T 2406.2-2009 standard, using an oxygen index meter (JF-3, Jiangfeng Instruments), with a sample size of 80mm×10mm×4mm. The samples were conditioned for 24 hours at 23±2℃ and 50±5% relative humidity before testing. Five samples were tested for each formula and the average value was taken.

[0123] 1.2 UL 94 vertical burning test The test was conducted in accordance with GB / T 2408-2008 standard. The sample size was 125mm×13mm×3.2mm. The sample was conditioned for 48 hours at 23±2℃ and 50±5% relative humidity before the test. During the test, the sample was fixed vertically and a 10mm high blue flame was used to burn the bottom for 10 seconds. The burning condition of the sample was observed and the burning time t1 was recorded. After the flame was extinguished, it was burned again for 10 seconds and the burning time t2 was recorded. It was observed whether there were any burning drops that ignited the absorbent cotton. Ten samples were tested for each formula and the UL 94 grade (V-0, V-1, V-2 or failed) was determined based on the test results.

[0124] 1.3 Cone calorimetry test The test was conducted in accordance with ISO 5660-1, using a cone calorimeter (FTT), with a sample size of 100mm×100mm×3mm and a radiant heat flux of 50kW / m². Data such as peak heat release rate (PHRR), total heat release (THR), time to ignition (TTI), average heat release rate (AHRR) and smoke generation were recorded. Three samples were tested for each formulation and the average value was taken.

[0125] 1.4 High temperature flame exposure test In the self-designed high-temperature flame exposure test, a sample with a size of 100mm×50mm×4mm was fixed on a bracket, and a propane flame (temperature of about 800℃) was directly applied to the sample surface for 30 seconds and then removed. The formation of a carbon layer on the sample surface was observed, and the temperature rise on the back of the sample was recorded (measured by a thermocouple). After the flame was removed, the sample was observed for another hour to record whether its structural integrity was maintained.

[0126] 2. Mechanical properties test 2.1 Tensile performance test The test was carried out according to GB / T 1040.2-2006 standard, using a universal material testing machine (CMT5105, Xinsansi), standard dumbbell type (1B type) samples, test speed of 50mm / min, test environment temperature of 23±2℃, relative humidity of 50±5%. The tensile strength, elongation at break and elastic modulus were recorded. Five samples were tested for each formula and the average value was taken.

[0127] 2.2 Bending performance test The test was conducted in accordance with GB / T 9341-2008 standard, using a universal material testing machine, sample size 80mm×10mm×4mm, three-point bending method, support distance 64mm, test speed 2mm / min, test environment temperature 23±2℃, relative humidity 50±5%. Record the bending strength and bending modulus. Test 5 samples for each formula and take the average value.

[0128] 2.3 Izod notched impact strength test The test was conducted in accordance with GB / T 1043.1-2008 standard, using an Izod impact tester (XJJD-5, New Rubber Technology), with a sample size of 80mm×10mm×4mm, a V-notch, a notch depth of 2mm, a test environment temperature of 23±2℃, and a relative humidity of 50±5%. The impact strength was recorded. Ten samples were tested for each formulation and the average value was taken.

[0129] 3. Thermal performance test 3.1 Heat Deformation Temperature (HDT) Test The test was conducted in accordance with GB / T 1634.2-2004 standard, using a hot deformation Vicat softening point tester (XRW-300A, Guiyang Precision), with a sample size of 80mm×10mm×4mm, a load of 0.45MPa, and a heating rate of 120℃ / h. The temperature at which the sample deformed by 0.2mm was recorded. Three samples were tested for each formulation and the average value was taken.

[0130] 3.2 Thermogravimetric analysis (TGA) A thermogravimetric analyzer (TGA / DSC 3+, Mettler-Toledo) with a sample mass of about 10 mg was used. The temperature was increased from room temperature to 800°C at a rate of 10°C / min under a nitrogen atmosphere, and the weight loss curve, weight loss starting temperature (T5%, corresponding to the temperature of 5% mass loss) and carbon residue rate at 600°C of the sample were recorded.

[0131] 4. Professional performance testing 4.1 Wear resistance test The roller abrasion test method was used. The samples were made into rectangular strips with a size of 50 mm × 10 mm × 5 mm. The samples were tested for 1000 cycles at a speed of 100 rpm under a load of 100 N. The mass loss and surface wear depth of the samples were recorded. Three samples were tested for each formulation and the average value was taken.

[0132] 4.2 Electrical insulation test The test was carried out in accordance with GB / T 1408.1-2016 standard, using a high voltage breakdown tester (HCDJC-100kV, Huace Electric), with a sample size of 100mm×100mm×2mm, and was tested at 23±2℃ and a relative humidity of 50±5%. The electrode diameter was 25mm, the voltage rise rate was 2kV / s, and the breakdown voltage was recorded. Five samples were tested for each formula and the average value was taken.

[0133] 4.3 Aging performance test The samples were placed in a high-temperature aging box and aged at 120°C for 1000 hours. The samples were taken out every 200 hours to test the tensile strength, flexural strength and oxygen index, and the performance retention rate was calculated.

[0134] 4.4 Simulated use environment test The prepared roller bracket samples were installed on a simulated conveying mechanism and operated in a high temperature environment of 200°C for 500 hours. The appearance, dimensional stability and surface wear of the samples were checked every 100 hours.

[0135] Test results and analysis Table 1 Flame retardant performance test results sample Oxygen index (%) UL 94 rating PHRR(kW / m²) THR(MJ / m²) TTI(s) Backside temperature rise after high temperature flame exposure (℃) Structural integrity (1h) Example 1 38.5 V-0 185 28.6 45 85 intact Example 2 42.8 V-0 162 25.4 53 72 intact Example 3 40.2 V-0 175 27.3 48 78 intact Example 4 41.5 V-0 168 26.2 50 75 intact Example 5 39.8 V-0 172 27.1 47 82 intact Example 6 40.6 V-0 170 26.8 49 80 intact Comparative Example 1 26.3 V-2 435 58.2 32 185 Partial melting deformation Comparative Example 2 30.5 V-1 328 45.1 38 145 Slight deformation Comparative Example 3 32.4 V-1 290 38.3 40 132 Slight deformation Comparative Example 4 33.8 V-0 252 35.6 42 120 Slight edge deformation Table 2 Mechanical properties test results sample Tensile strength(MPa) Elongation at break (%) Bending strength(MPa) Flexural modulus (MPa) Impact strength (kJ / m²) Example 1 40.2 110 65.3 3050 21.3 Example 2 42.5 95 72.6 3380 23.8 Example 3 41.8 102 68.4 3210 22.5 Example 4 44.1 105 71.2 3320 23.2 Example 5 43.2 98 70.5 3280 22.8 Example 6 42.8 103 69.8 3240 22.4 Comparative Example 1 32.5 75 45.2 2120 8.5 Comparative Example 2 34.8 85 48.6 2350 12.3 Comparative Example 3 36.2 90 52.4 2580 15.8 Comparative Example 4 38.5 95 58.2 2850 18.4 Table 3 Thermal performance test results sample HDT(℃) T5%(℃) 600℃ carbon residue rate (%) Example 1 132 318 36.5 Example 2 142 335 42.3 Example 3 138 326 38.9 Example 4 140 330 40.2 Example 5 135 325 39.6 Example 6 137 328 38.2 Comparative Example 1 95 265 18.3 Comparative Example 2 105 282 24.5 Comparative Example 3 112 290 28.4 Comparative Example 4 118 302 32.6 Table 4 Professional performance test results sample Wear resistance (mg / 1000 cycles) Breakdown voltage(kV / mm) Strength retention after aging at 120℃ for 1000h (%) Dimensional stability after simulated use environment test Example 1 15.2 26.5 87.5 good Example 2 12.5 28.3 92.3 excellent Example 3 13.8 27.4 89.6 good Example 4 11.6 27.8 90.8 excellent Example 5 12.2 28.2 91.5 excellent Example 6 12.8 27.5 90.2 good Comparative Example 1 35.6 18.2 65.4 Obvious deformation Comparative Example 2 28.3 21.5 70.2 Slight deformation Comparative Example 3 24.5 23.8 76.8 Slight deformation Comparative Example 4 20.8 25.2 80.5 Slight edge deformation As can be seen from Table 1, the oxygen index values ​​of Examples 1-6 of the present invention are all over 38%, much higher than 26.3-33.8% of Comparative Examples 1-4. This shows that the fire-resistant composite material of the present invention has significantly excellent flame retardant properties. In particular, in Example 2, due to the use of a higher content of phosphorus-nitrogen-silicon ternary synergistic flame retardant (35 parts by weight) and expanded graphite-manganese intercalation compound (30 parts by weight), the oxygen index reaches 42.8%, which is close to the level of some engineering plastic flame retardant modified materials.

[0136] In the UL 94 vertical burning test, all examples reached the V-0 level, indicating that the material can quickly self-extinguish after being directly burned by flames, and there is no burning dripping. In contrast, comparative example 1 only reached the V-2 level, comparative examples 2 and 3 were V-1 levels, and only comparative example 4 reached the V-0 level, but other flame retardant performance indicators were obviously inferior to those of the embodiments of the present invention.

[0137] The cone calorimetry test results show that the peak heat release rate (PHRR) and total heat release (THR) of the embodiments of the present invention are 50-62% and 50-56% lower than those of the comparative examples, respectively, which means that in a real fire situation, the material of the present invention releases less heat and is safer. At the same time, the time to ignition (TTI) of the embodiments is extended by about 15-65% compared with the comparative examples, indicating that the material has a longer emergency response time.

[0138] In the high temperature flame exposure test, the back temperature rise of the examples was significantly lower than that of the comparative examples, only 72-85°C, while the temperature rise of the comparative examples reached 120-185°C. In addition, all the examples still maintained intact structural integrity after 1 hour of flame exposure, while the comparative example 1 showed partial melting deformation, and the comparative examples 2-4 also showed varying degrees of deformation. These results fully verify the effectiveness of the "physical barrier-chemical blocking-thermal stability enhancement" trinity multiple fire retardant mechanism of the present invention.

[0139] As can be seen from Table 2, the mechanical properties of the embodiments of the present invention are significantly better than those of the comparative examples. The tensile strength of the embodiments is between 40.2-44.1MPa, 15-35% higher than that of the comparative example; the bending strength is between 65.3-72.6MPa, 20-60% higher than that of the comparative example; and the impact strength is between 21.3-23.8kJ / m², 28-150% higher than that of the comparative example. These excellent mechanical properties are due to the unique multi-scale structural synergistic enhancement mechanism and efficient compatibility system of the present invention.

[0140] It is particularly noteworthy that the mechanical properties of Examples 4 and 5 are the most excellent. This may be because Example 4 focuses on optimizing the synergistic effect of the phosphorus-nitrogen-silicon ternary synergistic flame retardant system and the expanded graphite-manganese intercalation compound, and Example 5 focuses on optimizing the synergistic effect of the high-temperature reinforcement system. These optimized designs enable the material to obtain excellent flame retardancy without sacrificing mechanical properties, and even obtain significant reinforcement effects.

[0141] The results in Table 3 show that the heat deformation temperature (HDT) of the embodiments of the present invention reaches 132-142°C, which is 30-40°C higher than that of the comparative example; the thermal decomposition starting temperature (T5%) reaches 318-335°C, which is about 15-25% higher than that of the comparative example; and the residual carbon rate at 600°C reaches 36.5-42.3%, which is about 20-100% higher than that of the comparative example. These data show that the material of the present invention has significant thermal stability and heat resistance.

[0142] In particular, the carbon residue rate at 600°C of Example 2 is as high as 42.3%, indicating that it can form more carbon layers at high temperatures, providing better heat insulation and oxygen barrier effects. This is consistent with its best performance in the flame retardant performance test, confirming the important role of high carbon residue rate in improving the flame retardant performance of materials.

[0143] Table 4 shows the professional performance test results for the actual application environment of the roller support. The wear resistance (mass loss 11.6-15.2 mg / 1000 cycles) of the embodiment of the present invention is significantly better than that of the comparative example (20.8-35.6 mg / 1000 cycles), indicating that it has a longer service life during the long-term operation of the conveying equipment.

[0144] The electrical insulation performance test shows that the breakdown voltage of the embodiment reaches 26.5-28.3 kV / mm, meeting the electrical safety requirements in industrial environments. More importantly, after aging at 120°C for 1000 hours, the strength retention rate of the embodiment still reaches 87.5-92.3%, which is significantly higher than 65.4-80.5% of the comparative example, indicating that the material has excellent long-term stability.

[0145] In the simulated use environment test which best reflects the actual use performance, all the examples still maintained good to excellent dimensional stability after running for 500 hours in a high temperature environment of 200°C, while the comparative example 1 showed obvious deformation, and the comparative examples 2-4 also had deformation to varying degrees. This fully proves the excellent applicability of the material of the present invention in high temperature industrial environments.

[0146] Through a comprehensive analysis of the comparative test results, the following conclusions can be drawn: 1. Effectiveness of multiple synergistic flame retardant mechanisms: The combination of the phosphorus-nitrogen-silicon ternary synergistic flame retardant and the expanded graphite-manganese intercalation compound of the present invention forms a more stable carbon layer structure through synergistic action, which significantly improves the flame retardant properties of the material. This synergistic effect was not achieved in Comparative Examples 3 and 4 because they lacked key synergistic mechanisms or preparation processes.

[0147] 2. Enhancement effect of multi-scale structure: The multi-scale structural design of the present invention from nanometer, micrometer to macroscopic enables each component to play a reinforcing role at different scales, solving the problem that it is difficult to balance flame retardancy and mechanical properties of traditional flame retardant materials. In particular, the addition of organosilicon-modified basalt fiber and fused quartz microfiber significantly improves the mechanical strength and dimensional stability of the material.

[0148] 3. Protection effect of temperature step response mechanism: The material of the present invention can gradually activate different protection mechanisms at different temperature stages, such as the hollow glass microsphere phase change material composite absorbs heat at a lower temperature to delay the temperature rise, the temperature-responsive core-shell structure cerium oxide nanoparticles release antioxidant active substances at a medium temperature, and the expanded graphite-manganese intercalation compound rapidly expands at a high temperature to form a heat insulation layer. This temperature step response mechanism was not realized in the comparative example.

[0149] 4. The key role of the preparation process: Although Comparative Example 4 contains some key components of the present invention, due to the use of the traditional one-step mixing and extrusion process, it fails to achieve full compatibility and synergy between the components, resulting in its performance being significantly lower than that of the examples. This proves the important influence of the multi-stage premixing and precisely controlled reaction extrusion process of the present invention on the material properties.

[0150] 5. Excellent performance in long-term use: The material of the present invention performs well in high temperature aging and simulated use environment tests, indicating that it not only has excellent short-term performance, but also has good long-term use stability, which is crucial for roller brackets in industrial environments.

[0151] In conclusion, through systematic comparative tests and comprehensive performance analysis, the comprehensive advantages of the fire-resistant composite material for roller brackets of the present invention in terms of flame retardancy, mechanical properties, thermal properties and professional application performance are fully demonstrated. This material not only solves the problem that traditional roller bracket materials are prone to failure in high temperature environments, but also provides excellent mechanical properties and long-term use stability, and is particularly suitable for high-temperature and high-risk industrial environments such as steel, electricity, petrochemicals, and mining.

[0152] The refractory composite material and its preparation method of the present invention have been tried out on the high-temperature conveying equipment of a large steel enterprise. After 6 months of follow-up observation, the roller bracket prepared by the material of the present invention has stable working performance in a high-temperature environment of more than 200°C, without deformation, cracking or functional failure. Compared with the original engineering plastic roller bracket (which needs to be replaced every 2 months), the service life is extended by more than 3 times, which significantly reduces the equipment maintenance cost and downtime risk.

Claims

1. A refractory composite material for a roller support, characterized in that: The refractory composite material comprises, by weight: 100-150 parts by weight of high crystalline copolymer polypropylene; 15-35 parts by weight of a ternary synergistic flame retardant of phosphorus, nitrogen and silicon, wherein the ternary synergistic flame retardant of phosphorus, nitrogen and silicon comprises 7-18 parts by weight of a non-halogen phosphorus, nitrogen and flame retardant, 5-12 parts by weight of an amide-modified ammonium polyphosphate and 3-8 parts by weight of polysiloxane-modified nano-silica; 8-20 parts by weight of mesoporous aluminum hydroxide; 12-30 parts by weight of expanded graphite-manganese intercalation compound; 3-12 parts by weight of microencapsulated red phosphorus; 6-18 parts by weight of ternary magnesium-aluminum-silicon layered composite material; 4-12 parts by weight of temperature-responsive core-shell cerium oxide nanoparticles; 3-10 parts by weight of organosilicon-modified basalt fiber; 2-7 parts by weight of fused silica microfibers; 3-9 parts by weight of maleic anhydride grafted polypropylene compatibilizer; 2-6 parts by weight of phosphite auxiliary antioxidant; 1-4 parts by weight of modified montmorillonite nanosheets; 0.5-2.5 parts by weight of hindered amine light stabilizer and hindered phenol synergistic antioxidant system; 1-5 parts by weight of a polyacid catalytic carbonizing agent; 2-8 parts by weight of hollow glass microsphere phase change material composite; 0.5-3 parts by weight of lubricating additives.

2. The refractory composite material for roller support according to claim 1, characterized in that: The preparation method of the expanded graphite-manganese intercalation compound comprises the following steps: Adding natural graphite sheets into a mixed solution of concentrated sulfuric acid and concentrated nitric acid to react, thereby obtaining an expanded graphite intermediate; The expanded graphite intermediate is added to an aqueous solution of manganese sulfate and potassium persulfate for ultrasonic dispersion, a sodium hydroxide solution is added dropwise to control the pH value, and then potassium permanganate is added for oxidation reaction; adding ascorbic acid to the reaction system to carry out a reduction reaction; The obtained product is treated with supercritical CO2, heat-treated under nitrogen protection, and then impregnated with a glycidyl methacrylate solution to obtain an expanded graphite-manganese intercalation compound.

3. The refractory composite material for roller support according to claim 1, characterized in that: The preparation method of the ternary magnesium-aluminum-silicon layered composite material comprises the following steps: Dissolving magnesium sulfate heptahydrate and aluminum sulfate 18hydrate in deionized water to obtain a metal salt solution, and dissolving sodium silicate in deionized water to obtain a sodium silicate solution; Under the condition of controlling the pH value, adding the sodium silicate solution dropwise into the metal salt solution to carry out a coprecipitation reaction; The coprecipitation system is hydrothermally treated at 160-180° C.; The product after hydrothermal treatment is intercalated with dodecyltrimethylammonium bromide; 3-aminopropyltriethoxysilane is added to the intercalation-modified dispersion for functionalization treatment to obtain a ternary magnesium-aluminum-silicon layered composite material.

4. The refractory composite material for roller supports according to claim 1, characterized in that: The method for preparing the temperature-responsive core-shell cerium oxide nanoparticles comprises the following steps: Cerium nitrate hexahydrate and citric acid solution are mixed and pH value is adjusted to prepare cerium core nanoparticles; dispersing the cerium core nanoparticles in an ethanol / water mixed solvent, and adding polyvinyl pyrrolidone as a dispersant; adding tetraethoxysilane and poly (N-isopropylacrylamide) solution dropwise into the dispersion to form a primary shell layer; Adding N-isopropylacrylamide monomer, methacrylic acid and N,N'-methylenebisacrylamide crosslinker to the primary shell dispersion, and initiating polymerization reaction by ammonium persulfate to form a temperature-responsive shell; The surface of the obtained product is functionalized with a phosphodiester compound to obtain temperature-responsive core-shell structured cerium oxide nanoparticles.

5. The fire-resistant composite material for roller support according to claim 1, characterized in that: The method for preparing the hollow glass microsphere phase change material composite comprises the following steps: The surface of the hollow glass microspheres was treated with 3-aminopropyltriethoxysilane; The n-octadecane and stearic acid are melted and mixed, and butylated hydroxytoluene is added to obtain a phase change material mixture; Injecting the molten phase change material mixture into the surface-treated hollow glass microspheres under vacuum conditions; The filled microspheres are surface encapsulated with epoxy resin and polyamide curing agent; The encapsulated product is subjected to graded curing treatment to obtain a hollow glass microsphere phase change material composite.

6. A method for preparing a refractory composite material for a roller support according to any one of claims 1 to 5, characterized in that: The following steps are involved: (1) Multi-stage premixing: firstly, high crystalline copolymer polypropylene, maleic anhydride grafted polypropylene compatibilizer and hindered amine light stabilizer are mixed with hindered phenol synergistic antioxidant system; mesoporous aluminum hydroxide is mixed with ternary magnesium aluminum silicon layered composite material respectively, and then mixed with phosphite auxiliary antioxidant; organic silicon modified basalt fiber, fused quartz microfiber, modified montmorillonite nanosheet and polyacid catalytic carbonizing agent are mixed; after combining the above three mixtures, phosphorus nitrogen silicon ternary synergistic flame retardant is added; then expanded graphite-manganese intercalation compound and microencapsulated red phosphorus, as well as temperature-responsive core-shell structure cerium oxide nanoparticles, hollow glass microsphere phase change material composite and lubricating additive are added in sequence to obtain a premix; (2) Multi-stage reaction extrusion: the premix is ​​extruded in a twin-screw extruder, wherein the extruder is configured with nine temperature control zones, the temperature of the feed section is 160-170°C, the temperature of the first compression section is 180-190°C, the temperature of the first mixing section is 190-200°C, the temperature of the first reaction section is 200-210°C, the temperature of the second mixing section is 210-220°C, the temperature of the second reaction section is 215-225°C, the temperature of the second compression section is 205-215°C, the temperature of the homogenization section is 195-205°C, and the temperature of the head section is 185-195°C; (3) Hot pelletizing and tempering: The extruded material strips are water cooled and then hot pelletized, the pellets are dried, and then heat tempered under nitrogen protection to obtain refractory composite material particles; (4) Precision molding of roller brackets: The refractory composite material particles are used to prepare roller brackets by precision injection molding technology, and then pre-treated and annealed to obtain the final product.

7. The method for preparing a refractory composite material for a roller support according to claim 6, characterized in that: The preparation method of the organosilicon-modified basalt fiber comprises the following steps: After drying the basalt fiber, the surface was degreased with acetone; The treated fibers are immersed in a mixed solution of hydrogen peroxide and concentrated sulfuric acid for surface activation; preparing a mixed silane coupling agent solution of γ-aminopropyltriethoxysilane and γ-methacryloxypropyltrimethoxysilane; Immersing the activated fiber in the silane coupling agent solution to perform a coupling reaction; The coupled fibers are dispersed in toluene, and decamethylcyclopentasiloxane and a platinum catalyst are added to perform polysiloxane encapsulation treatment to obtain organosilicon-modified basalt fibers.

8. The method for preparing a refractory composite material for a roller support according to claim 6, characterized in that: The multi-stage premixing process in step (1) is specifically as follows: First, 100-150 parts by weight of high crystalline copolymer polypropylene, 3-9 parts by weight of maleic anhydride grafted polypropylene compatibilizer and 0.5-2.5 parts by weight of hindered amine light stabilizer and hindered phenol synergistic antioxidant system are premixed at 60-70° C. for 5-8 minutes at a mixing speed of 600-800 rpm; Mix 8-20 parts by weight of mesoporous aluminum hydroxide and 6-18 parts by weight of ternary magnesium aluminum silicon layered composite material, add 2-6 parts by weight of phosphite auxiliary antioxidant, and mix at 35-45° C. for 4-6 minutes; 3-10 parts by weight of organosilicon-modified basalt fibers, 2-7 parts by weight of fused silica microfibers, 1-4 parts by weight of modified montmorillonite nanosheets, and 1-5 parts by weight of a polyacid catalytic carbonizing agent are mixed by low-speed stirring for 3-5 minutes; Add the obtained inorganic filler mixture and fiber composite system to the base mixture, mix for 6-8 minutes at 55-65°C and a mixing speed of 500-700rpm, then add 15-35 parts by weight of phosphorus nitrogen silicon ternary synergistic flame retardant, and continue mixing for 4-6 minutes; Add 12-30 parts by weight of expanded graphite-manganese intercalation compound and 3-12 parts by weight of microencapsulated red phosphorus, mix at 50-60° C. for 5-7 minutes at a mixing speed of 400-600 rpm; 4-12 parts by weight of temperature-responsive core-shell cerium oxide nanoparticles, 2-8 parts by weight of hollow glass microsphere phase change material composite and 0.5-3 parts by weight of lubricating additive are added, and finally mixed at 45-55° C. for 6-8 minutes at a mixing speed of 300-500 rpm.

9. The method for preparing a refractory composite material for a roller support according to claim 6, characterized in that: During the multi-stage reaction extrusion process in step (2), the screw speed is set to: 80-100 rpm in the front section, 100-120 rpm in the middle section, and 70-90 rpm in the rear section; the melt residence time is controlled at 2.5-3.5 minutes; a negative pressure exhaust device is installed in the first reaction section, and the pressure is controlled at -0.08 to -0.1 MPa.

10. The method for preparing a refractory composite material for a roller support according to claim 6, characterized in that: The roller bracket precision forming process in step (4) is specifically as follows: The tempered particles obtained in step (3) are used to prepare a roller bracket by precision injection molding technology, the injection molding machine adopts a multi-point gate design, and the barrel temperature is set to 210-220° C., 215-225° C., 220-230° C., and 215-225° C. from back to front; Mold temperature zoning control: cavity area 45-55℃, runner area 60-70℃; The injection pressure is set to: 90-100MPa in the first stage and 70-80MPa in the second stage; The injection speed is controlled by five stages of gradual change: 10%, 30%, 60%, 40%, 20%; The holding time is set to 18-25 seconds, and the holding pressure is 60-70MPa; The cooling time is 35-45 seconds, and the in-mold cooling adopts variable temperature technology; Pre-treat the formed roller bracket at 90-100°C for 0.5-1 hour to release internal stress; Under nitrogen protection, anneal at 130-150°C for 1.5-2.5 hours; The mixture was cooled to room temperature at a rate of 5-8°C / min to obtain the final product.