Thermal-insulation cold-proof material as well as preparation method and application thereof

Abstract

The invention relates to the technical field of thermal insulation materials, in particular to a thermal insulation cold-proof material and a preparation method and application thereof. The invention provides a thermal-insulation cold-proof material, which is prepared from the following raw materials in parts by mass: 80 to 95 parts of flame-retardant modified polyolefin fiber and 5 to 20 parts of low-melting-point adhesive fiber. The preparation method of the thermal-insulation cold-proof material comprises the following steps: uniformly mixing the flame-retardant modified polyolefin fibers and the low-melting-point adhesive fibers, and opening and removing impurities in an opener; then the cotton enters a carding machine through a cotton storage box and a cotton feeding machine in sequence for carding and separation; feeding into a lapping machine for lapping, and setting to form fiber cotton; the fiber cotton is trimmed and rolled in sequence, and then the heat-preservation and cold-proof material is obtained. The thermal-insulation cold-proof material disclosed by the invention is light in weight, environment-friendly, good in flame retardant property, free of harmful substances and recyclable; the preparation process is simple, and the production process is environment-friendly.

Description

Technical Field

[0001] This invention relates to the field of thermal insulation materials technology, and in particular to a thermal insulation and cold protection material, its preparation method and application. Background Technology

[0002] In order to maintain a stable internal temperature environment and reduce the energy consumption of heating or cooling equipment during the operation of rail vehicles, a layer of thermal insulation and cold protection material needs to be placed between the steel structure of the car body and the interior facilities. This material reduces heat exchange between the inside and outside of the vehicle and also provides some sound insulation and noise reduction. It is widely used in the interior decoration materials of rail vehicles.

[0003] Fibrous insulation materials are commonly used for thermal insulation and cold protection in rail transit, possessing advantages such as light weight, good sound absorption, and good thermal insulation properties. Currently, commonly used insulation and cold protection materials in the rail transit field mainly include inorganic fiber materials such as glass wool and organic fiber materials such as carbon fiber wool. Glass wool, in particular, is a man-made inorganic fiber made by high-temperature bonding of blown glass fibers. It is porous, possesses good thermal insulation and sound absorption properties, and is chemically stable. However, the density of glass wool is generally between 24 and 40 kg / m³. 3 The overall weight of glass wool is relatively large, affecting the vehicle's load-bearing capacity and operating efficiency. Secondly, the sound absorption and heat insulation performance of glass wool is severely affected after it absorbs moisture, resulting in poor performance in humid environments. During installation, glass wool is brittle and easily breaks, readily generating dust, causing environmental pollution and irritating the respiratory tract and skin. Glass wool is also not easily degradable, forming solid waste and causing secondary pollution to the environment. Carbon fiber wool (also known as pre-oxidized fiber wool) is generally made from carbon fiber or pre-oxidized fiber as raw materials through high-temperature oxidation. It has a lower density, typically 10-15 kg / m³. 3 It has advantages such as low density, high temperature resistance, wear resistance, corrosion resistance, high strength, and a certain degree of tensile elasticity. However, carbon fiber cotton has a complex manufacturing process and is very expensive, so it is generally only used in high-speed trains or urban rail transit. Secondly, as a composite material, carbon fiber cotton is difficult to separate effectively due to its strong interlayer bonding, making its recycling relatively difficult and also causing environmental pollution problems during the recycling process.

[0004] With the rapid development of modern industry, energy conservation, emission reduction, and environmental protection are becoming the focus of attention across all sectors. To achieve lightweight, green, and sustainable development in rail transit, the selection of lightweight, environmentally friendly, and recyclable thermal insulation and cold-proofing materials is crucial. These materials not only affect the train's energy efficiency, environmental friendliness, and operating costs, but also directly impact passenger comfort and satisfaction, serving as a key standard for evaluating the design and manufacturing level of railway trains. Therefore, in the research and development and production of railway trains, high importance should be attached to the selection and performance-price optimization of thermal insulation and cold-proofing materials to continuously enhance the train's overall competitiveness and market attractiveness.

[0005] In view of this, this invention is hereby proposed. Summary of the Invention

[0006] The primary objective of this invention is to provide a thermal insulation and cold-proof material that is lightweight, flame-retardant, free of harmful substances, environmentally friendly, and easily recyclable.

[0007] The second objective of this invention is to provide a method for preparing thermal insulation and cold-proof materials, which has a simple process, short production cycle, low production cost, high production efficiency, and no harmful substances are generated during the production process.

[0008] A third objective of this invention is to provide the application of thermal insulation and cold protection materials in rail transit.

[0009] In order to achieve the above-mentioned objectives of the present invention, the following technical solution is adopted:

[0010] In a first aspect, the present invention provides a thermal insulation and cold protection material, comprising, by weight parts, the following raw materials: 80-95 parts of flame-retardant modified polyolefin fiber and 5-20 parts of low-melting-point adhesive fiber.

[0011] Furthermore, the flame-retardant modified polyolefin fiber comprises, by weight parts, the following raw materials:

[0012] The mixture contains 60-80 parts polypropylene, 10-20 parts polyethylene, 10-20 parts flame retardant, 0.5-1 part antioxidant, and 0.5-1 part lubricant.

[0013] Furthermore, it includes at least one of the following features (1) to (3);

[0014] (1) The flame retardant includes phosphorus-nitrogen flame retardants;

[0015] (2) The antioxidants include antioxidant 1010;

[0016] (3) The lubricant includes calcium stearate.

[0017] Furthermore, the preparation method of the flame-retardant modified polyolefin fiber includes the following steps:

[0018] Polypropylene, polyethylene, flame retardant, antioxidant and lubricant are mixed evenly to obtain a mixture.

[0019] The mixture is sequentially melt-extruded and melt-spun to obtain filament bundles;

[0020] The filament bundle is sequentially cooled, oiled, stretched, and wound to obtain the flame-retardant modified polyolefin fiber.

[0021] Furthermore, the extrusion temperature of the melt extrusion is 180–220°C, and the screw speed is 100–200 r / min;

[0022] And / or, the spinning temperature of the melt spinning is 220-250°C, and the spinning speed is 800-1200 m / min.

[0023] Furthermore, the method for preparing the flame retardant includes the following steps:

[0024] Ammonium polyphosphate was dispersed in a solution, and after adjusting the pH of the system to 7.5–8.5, dimethyldiethoxysilane and tetraethyl orthosilicate were added. After the reaction, modified ammonium polyphosphate was obtained.

[0025] The modified ammonium polyphosphate, melamine cyanurate, and pentaerythritol phosphate are mixed evenly to obtain the flame retardant.

[0026] Furthermore, the method for preparing the flame retardant includes at least one of the following features (1) to (3);

[0027] (1) The mass ratio of the ammonium polyphosphate, the dimethyldiethoxysilane and the tetraethyl orthosilicate is (110-120):(22-25):(22-25);

[0028] (2) The reaction temperature is 50-60℃ and the time is 3-4h;

[0029] (3) The mass ratio of the modified ammonium polyphosphate, the melamine cyanurate and the pentaerythritol phosphate is (10-15): (8-10): (5-8).

[0030] Furthermore, the low-melting-point adhesive fiber comprises: a fiber mainly composed of a high-melting-point polyester core layer and a low-melting-point polyester sheath layer.

[0031] Secondly, the present invention also provides a method for preparing the thermal insulation and cold-proof material as described above, comprising the following steps:

[0032] After the flame-retardant modified polyolefin fiber and the low-melting-point adhesive fiber are mixed evenly, they are fed into the opening machine for opening and impurity removal; then they are fed into the carding machine through the cotton storage box and the cotton feeder for carding and separation; then they are fed into the web laying machine for web laying and then shaped to form fiber cotton; the fiber cotton is then trimmed and wound to obtain the heat insulation and cold protection material.

[0033] Thirdly, the present invention also provides the application of the above-mentioned thermal insulation and cold protection materials in rail transit.

[0034] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0035] The thermal insulation and cold protection material of this invention has a low density, which is beneficial for lightweighting; it has good flame retardant properties; it does not contain harmful substances, which meets the environmental protection requirements for materials used in the interior of rail vehicles; it is easy to recycle and can be converted into new raw materials through mechanical recycling, melt regeneration, chemical recycling and other methods, so as to realize resource recycling.

[0036] The method for preparing thermal insulation and cold protection materials of the present invention uses thermoplastic environmentally friendly materials as raw materials, which are green and environmentally friendly and meet environmental protection requirements. No harmful gases, liquids, dust, etc. are generated during the production process, and the production environment is good. The raw material price is reasonable and the raw material utilization rate is high, which effectively reduces costs and resource waste. The required production equipment is mature and universal, and its production equipment has a high degree of overlap with the polyester fiber production equipment in the garment industry. The process flow is simple, the production cycle is short, the production cost is low, and the production efficiency is high. Detailed Implementation

[0037] The technical solution of the present invention will be clearly and completely described below with reference to specific embodiments. However, those skilled in the art will understand that the embodiments described below are some embodiments of the present invention, but not all embodiments, and are only used to illustrate the present invention, and should not be regarded as limiting the scope of the present invention. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention. Where specific conditions are not specified in the embodiments, conventional conditions or conditions recommended by the manufacturer shall be followed. Where the manufacturers of reagents or instruments are not specified, they are all conventional products that can be purchased commercially.

[0038] The following is a detailed description of a thermal insulation and cold-proof material of the present invention, its preparation method, and its application.

[0039] In some embodiments of the present invention, a thermal insulation and cold protection material is provided, comprising the following raw materials by weight: 80-95 parts of flame-retardant modified polyolefin fiber and 5-20 parts of low-melting-point adhesive fiber.

[0040] The raw materials of the thermal insulation and cold protection material of the present invention include flame-retardant modified polyolefin fiber and low-melting-point adhesive fiber; wherein, the flame-retardant modified polyolefin fiber is the main material of the cold protection material, which is the key difference from conventional cold protection materials, while the low-melting-point adhesive fiber is used to make upright cotton, and its main function is to bind the loose flame-retardant modified polyolefin fiber together to form a stable block cotton material.

[0041] The density of the thermal insulation and cold protection material of this invention is 10-40 kg / m³. 3 This is beneficial for lightweight design.

[0042] The thermal insulation and cold protection material of the present invention modifies the polyolefin plastic fibers with flame retardants, resulting in good flame retardant properties, an oxygen index greater than 50.0, and a fire rating that can reach EN 45545-2:2020R1.

[0043] The thermal insulation and cold protection material of this invention uses thermoplastic environmentally friendly materials as raw materials. It is a green and environmentally friendly material that does not contain harmful substances and meets the environmental protection requirements for interior materials of rail vehicles.

[0044] The thermal insulation and cold protection material of the present invention is easy to recycle and can be transformed into new raw materials through mechanical recycling, melting regeneration, chemical recycling and other methods, so as to realize resource recycling.

[0045] In some embodiments of the present invention, the raw materials of the thermal insulation and cold protection material typically, but not limitingly, include flame-retardant modified polyolefin fibers in the range of 80, 82, 84, 86, 88, 90, 92, 94, 95 parts by mass, or any two of these; and low-melting-point adhesive fibers in the range of 5, 8, 10, 12, 14, 16, 18, 20 parts by mass, or any two of these.

[0046] In some preferred cases, the ratio of the flame-retardant modified polyolefin fiber to the low-melting-point adhesive fiber in the raw materials of the thermal insulation and cold-proof material of the present invention is 8:2 to 7:3. This ensures that the amount of the low-melting-point adhesive fiber is sufficient to bond the flame-retardant modified polyolefin fiber as a whole, while avoiding excessive use of the low-melting-point adhesive fiber, which would prevent the cold-proof properties of the main material from being fully utilized. Furthermore, excessive use would result in more fusion points not being bonded to the fiber, reducing the sound absorption performance of the cotton and increasing the thermal conductivity.

[0047] In some embodiments of the present invention, the flame-retardant modified polyolefin fiber comprises, by weight parts, the following raw materials:

[0048] The mixture contains 60-80 parts polypropylene, 10-20 parts polyethylene, 10-20 parts flame retardant, 0.5-1 part antioxidant, and 0.5-1 part lubricant.

[0049] In some embodiments of the present invention, the mass fraction of polypropylene in the raw materials of the flame-retardant modified polyolefin fiber can be 60 parts, 64 parts, 68 parts, 72 parts, 76 parts, 80 parts, or any combination thereof; the mass fraction of polyethylene can be 10 parts, 12 parts, 14 parts, 16 parts, 18 parts, 20 parts, or any combination thereof; the mass fraction of flame retardant can be 10 parts, 12 parts, 14 parts, 16 parts, 18 parts, 20 parts, or any combination thereof; the mass fraction of antioxidant can be 0.5 parts, 0.6 parts, 0.7 parts, 0.8 parts, 0.9 parts, 1 part, or any combination thereof; and the mass fraction of lubricant can be 0.5 parts, 0.6 parts, 0.7 parts, 0.8 parts, 0.9 parts, 1 part, or any combination thereof.

[0050] In some embodiments of the present invention, flame retardants include, but are not limited to, phosphorus-nitrogen-based flame retardants.

[0051] In some embodiments of the present invention, antioxidants include, but are not limited to, antioxidant 1010.

[0052] In some embodiments of the present invention, the lubricant includes, but is not limited to, calcium stearate.

[0053] In some embodiments of the present invention, the method for preparing flame-retardant modified polyolefin fibers includes the following steps:

[0054] Polypropylene, polyethylene, flame retardant, antioxidant and lubricant are mixed evenly to obtain a mixture.

[0055] After the mixture is successively subjected to melt extrusion and melt spinning, a filament bundle is obtained;

[0056] The fiber bundles are sequentially cooled, oiled, stretched, and wound to obtain flame-retardant modified polyolefin fibers.

[0057] In some embodiments of the present invention, the extrusion temperature of melt extrusion is 180–220°C, and the screw speed is 100–200 r / min; typically, but not limitingly, for example, the extrusion temperature of melt extrusion can be a range of 180°C, 200°C, 220°C, or any combination thereof; the screw speed of melt extrusion can be a range of 100 r / min, 150 r / min, 200 r / min, or any combination thereof.

[0058] In some embodiments of the present invention, the spinning temperature of melt spinning is 220–250°C, and the spinning speed is 800–1200 m / min; typically, but not limitingly, for example, the spinning temperature of melt spinning can be 220°C, 230°C, 240°C, 250°C, or any combination thereof; the spinning speed of melt spinning can be 800 m / min, 900 m / min, 1000 m / min, 1100 m / min, 1200 m / min, or any combination thereof.

[0059] In some embodiments of the present invention, the method for preparing the flame retardant includes the following steps:

[0060] Ammonium polyphosphate was dispersed in a solution, and after adjusting the pH of the system to 7.5–8.5, dimethyldiethoxysilane and tetraethyl orthosilicate were added. After the reaction, modified ammonium polyphosphate was obtained.

[0061] Modified ammonium polyphosphate, melamine cyanurate, and pentaerythritol phosphate were mixed evenly to obtain a flame retardant.

[0062] In the preparation method of the flame retardant of the present invention, modified ammonium polyphosphate is used. The ammonium polyphosphate is microencapsulated, which improves its hydrophobicity, thermal stability and compatibility with the resin matrix.

[0063] In some embodiments of the present invention, the solution comprises ethanol and water; preferably, the ratio of ammonium polyphosphate, ethanol and water is 110-120g: 400-500mL: 200-250mL.

[0064] In some embodiments of the present invention, ammonia is added to adjust the pH of the system to 8.

[0065] In some embodiments of the present invention, the mass ratio of ammonium polyphosphate, dimethyldiethoxysilane, and tetraethyl orthosilicate is (110–120):(22–25):(22–25); typically, but not limitingly, for example, the mass ratio of ammonium polyphosphate, dimethyldiethoxysilane, and tetraethyl orthosilicate can be 110:22:22, 115:23:23, 120:25:25, 110:25:25, 120:22:22, 115:22:25, etc.

[0066] In some embodiments of the present invention, the reaction temperature is 50-60°C and the reaction time is 3-4 hours; preferably, the reaction is carried out under stirring; more preferably, the stirring rate is 150-180 r / min.

[0067] In some embodiments of the present invention, after the reaction, the process further includes: sequentially filtering, washing with anhydrous ethanol, washing with distilled water, vacuum filtering, and drying to obtain modified ammonium polyphosphate.

[0068] In some embodiments of the present invention, the mass ratio of modified ammonium polyphosphate, melamine cyanurate, and pentaerythritol phosphate is (10-15):(8-10):(5-8); typically, but not limitingly, for example, the mass ratio of modified ammonium polyphosphate, melamine cyanurate, and pentaerythritol phosphate can be 10:8:5, 13:9:6, 15:10:8, 10:10:8, 15:8:5, 10:10:5, etc.

[0069] In some embodiments of the present invention, the low-melting-point adhesive fiber comprises: a fiber mainly composed of a high-melting-point polyester (PET) core layer and a low-melting-point polyester (LMPET) sheath layer; in some optional embodiments, the low-melting-point adhesive fiber adopts 4080 from Korea Whewish Co., Ltd., Celbond series from Hearst Corporation, etc.; furthermore, the melting point of the low-melting-point adhesive fiber includes: the melting point of the sheath layer LMPET is 110°C, and the melting point of the core layer PET is 259°C.

[0070] In some embodiments of the present invention, the method for preparing the thermal insulation and cold-proof material includes the following steps:

[0071] After the flame-retardant modified polyolefin fiber and the low-melting-point adhesive fiber are mixed evenly, they are fed into the opening machine for opening and impurity removal; then they are fed into the carding machine through the cotton storage box and the cotton feeder for carding and separation; then they are fed into the web laying machine for web laying and then shaped to form fiber cotton; after the fiber cotton is trimmed and rolled up, the heat insulation and cold protection material is obtained.

[0072] The method for preparing the thermal insulation and cold protection material of the present invention uses thermoplastic environmentally friendly materials, which are green and environmentally friendly, do not contain harmful substances, meet environmental protection requirements, and generate no harmful gases, liquids, dust, etc. during the production process, resulting in a good production environment.

[0073] The method for preparing the thermal insulation and cold protection material of the present invention uses raw materials with reasonable prices and high utilization rate, effectively reducing costs and resource waste.

[0074] The method for preparing the thermal insulation and cold protection material of the present invention requires mature and universal production equipment. Its production equipment has a high degree of overlap with the polyester fiber production equipment in the garment industry. The process is simple, the production cycle is short, the production cost is low, and the production efficiency is high.

[0075] In some embodiments of the present invention, the method for preparing thermal insulation and cold-proof materials specifically includes the following steps:

[0076] Flame-retardant modified polyolefin fibers and low-melting-point adhesive fibers are put into a cotton blender and mechanically stirred and mixed to ensure that the fibers are fully and evenly mixed.

[0077] After being mixed evenly, the fibers enter the opening machine from the blending machine. The mechanical force and airflow force are used to loosen the fiber bundles. The airflow is used to separate impurities and short fibers from the fiber bundles, thus achieving the initial opening and impurity removal of the fibers.

[0078] Then it is temporarily stored in the cotton storage box, which serves to buffer and stabilize the supply;

[0079] Then the fiber is fed from the storage box into the feeder. The feeder controls the fiber supply speed and amount to ensure that the fiber can enter the carding machine evenly and continuously.

[0080] After entering the carding machine, the fibers are combed and separated by the action of multiple sets of comb bars and comb teeth. The comb teeth will tear and straighten the fiber material, so that impurities and coarse fibers can be separated between the fibers.

[0081] The fibers are then fed into a web-laying machine, where they are gradually pulled out and spread into a web to obtain a fiber web.

[0082] The fiber web is stacked in multiple layers and enters the heat setting unit. Under high temperature and pressure, the low melting point bonding fibers melt and are cooled to achieve the setting of the whole cotton, forming fiber cotton.

[0083] The fiber cotton is trimmed at the edges by a trimming machine to remove irregular parts, and then wound and packaged by a winding machine to obtain thermal insulation and cold protection material.

[0084] In some embodiments of the present invention, the temperature used in the heat setting unit is 110°C to 130°C, and the linear pressure used in the heat setting unit is 30N / mm to 80N / mm.

[0085] In some embodiments of the present invention, thermal insulation and cold protection materials are used in rail transit; for example, in interior materials of rail vehicles.

[0086] Example 1

[0087] The method for preparing the thermal insulation and cold protection material provided in this embodiment includes the following steps:

[0088] Eighty parts of flame-retardant modified polyolefin fiber and 20 parts of low-melting-point PET adhesive fiber (4080 fiber, from Korea's Hwayish Co., Ltd.) are mixed evenly in a cotton blending machine. The fibers are then initially opened and impurities removed using mechanical and airflow forces. After temporary storage in a cotton storage box, the fibers are fed into a carding machine for carding and separation. The fibers are then fed into a web-laying machine, where they are gradually pulled out and spread into a web to form a fiber web. The fiber web is stacked in multiple layers and then heat-set in a heat-setting unit at 120°C and 50 N / mm to form fiber cotton. The fiber cotton is then trimmed by an edge trimmer and wound and packaged by a winding machine to obtain a thermal insulation and cold-proof material.

[0089] The preparation method of flame-retardant modified polyolefin fiber includes the following steps:

[0090] Add 65 parts of polypropylene granules, 10 parts of polyethylene granules, 20 parts of flame retardant, 0.5 parts of antioxidant 1010 and 0.5 parts of calcium stearate lubricant to a high-speed mixer and mix evenly to obtain a mixture.

[0091] The mixture is added to a twin-screw extruder for melt extrusion at an extrusion temperature of 200℃ and a screw speed of 180 r / min to obtain the extruded material.

[0092] After the extruded material is metered by a metering pump, it is fed into a melt spinning machine for melt spinning. The spinning temperature is 220℃ and the spinning speed is 1000m / min. The spun filaments are cooled, oiled, stretched and wound in sequence to obtain flame-retardant modified polyolefin fibers.

[0093] The preparation method of flame retardant includes the following steps:

[0094] 500 mL of ethanol and 250 mL of deionized water were mixed, and 120 g of ammonium polyphosphate was added. After thorough dispersion, ammonia water was added dropwise to adjust the pH of the system to 8. Then, 25 g of dimethyldiethoxysilane and 25 g of tetraethyl orthosilicate were added. After stirring evenly, the mixture was reacted at 50 °C for 3 h with a stirring rate of 180 r / min. The mixture was then filtered, washed three times with anhydrous ethanol, washed twice with distilled water, filtered under vacuum, and dried in a vacuum drying oven at 75 °C for 24 h to obtain modified ammonium polyphosphate.

[0095] 15 parts of the modified ammonium polyphosphate, 10 parts of melamine cyanurate and 8 parts of pentaerythritol phosphate were placed in a high-speed mixer and mixed evenly to obtain a flame retardant.

[0096] Example 2

[0097] The method for preparing the thermal insulation and cold protection material provided in this embodiment includes the following steps:

[0098] 85 parts of flame-retardant modified polyolefin fiber and 15 parts of low-melting-point PET adhesive fiber are mixed evenly in a cotton blending machine. Then, the mixture enters an opening machine, where mechanical and airflow forces are used to initially open and remove impurities from the fibers. After being temporarily stored in a cotton storage box, the fibers are fed into a carding machine for carding and separation. Then, the fibers are fed into a web-laying machine, where they are gradually pulled out and spread into a web to obtain a fiber web. The fiber web is stacked in multiple layers and then enters a heat-setting unit for setting under high temperature and pressure to form fiber cotton. The fiber cotton is then trimmed by an edge trimmer and wound and packaged by a winding machine to obtain a thermal insulation and cold-proof material.

[0099] The preparation method of flame-retardant modified polyolefin fiber includes the following steps:

[0100] Add 60 parts of polypropylene granules, 15 parts of polyethylene granules, 18 parts of flame retardant, 0.8 parts of antioxidant 1010 and 0.8 parts of calcium stearate lubricant to a high-speed mixer and mix evenly to obtain a mixture.

[0101] The mixture is added to a twin-screw extruder for melt extrusion at an extrusion temperature of 210℃ and a screw speed of 150 r / min to obtain the extruded material.

[0102] After the extruded material is metered by a metering pump, it is fed into a melt spinning machine for melt spinning. The spinning temperature is 230℃ and the spinning speed is 900m / min. The spun filaments are cooled, oiled, stretched and wound in sequence to obtain flame-retardant modified polyolefin fibers.

[0103] The preparation method of flame retardant includes the following steps:

[0104] 480 mL of ethanol and 240 mL of deionized water were mixed, and 115 g of ammonium polyphosphate was added. After thorough dispersion, ammonia water was added dropwise to adjust the pH of the system to 8. Then, 24 g of dimethyldiethoxysilane and 24 g of tetraethyl orthosilicate were added. After stirring evenly, the mixture was reacted at 55 °C for 3 h with a stirring rate of 160 r / min. The mixture was then filtered, washed three times with anhydrous ethanol, washed twice with distilled water, filtered under vacuum, and dried in a vacuum drying oven at 75 °C for 24 h to obtain modified ammonium polyphosphate.

[0105] The modified ammonium polyphosphate (13 parts), melamine cyanurate (9 parts), and pentaerythritol phosphate (7 parts) were mixed evenly in a high-speed mixer to obtain the flame retardant.

[0106] Example 3

[0107] The method for preparing the thermal insulation and cold protection material provided in this embodiment includes the following steps:

[0108] Ninety parts of flame-retardant modified polyolefin fiber and ten parts of low-melting-point PET adhesive fiber are fed into a cotton blender and mixed evenly. Then, the cotton blender enters an opening machine, where mechanical force and airflow force are used to achieve initial opening and impurity removal of the fibers. After being temporarily stored in a cotton storage box, the cotton is fed into a carding machine for fiber carding and separation. Then, it is fed into a web-laying machine, where the fiber material is gradually pulled out and spread into a web to obtain a fiber web. The fiber web is stacked in multiple layers and enters a heat-setting unit for setting under high temperature and pressure to form fiber cotton. The fiber cotton is then trimmed by an edge trimmer and wound and packaged by a winding machine to obtain a thermal insulation and cold-proof material.

[0109] The preparation method of flame-retardant modified polyolefin fiber includes the following steps:

[0110] Add 70 parts of polypropylene granules, 12 parts of polyethylene granules, 16 parts of flame retardant, 0.7 parts of antioxidant 1010 and 0.7 parts of calcium stearate lubricant to a high-speed mixer and mix evenly to obtain a mixture.

[0111] The mixture is added to a twin-screw extruder for melt extrusion at an extrusion temperature of 220°C and a screw speed of 150 r / min to obtain the extruded material.

[0112] After being metered by a metering pump, the extruded material is fed into a melt spinning machine for melt spinning. The spinning temperature is 240℃ and the spinning speed is 1100m / min. The spun filaments are then cooled, oiled, stretched, and wound in sequence to obtain flame-retardant modified polyolefin fibers.

[0113] The preparation method of flame retardant includes the following steps:

[0114] 450 mL of ethanol and 225 mL of deionized water were mixed, and 112 g of ammonium polyphosphate was added. After thorough dispersion, ammonia water was added dropwise to adjust the pH of the system to 8. Then, 23 g of dimethyldiethoxysilane and 23 g of tetraethyl orthosilicate were added. After stirring evenly, the mixture was reacted at 55 °C for 3 h with a stirring rate of 155 r / min. The mixture was then filtered, washed three times with anhydrous ethanol, washed twice with distilled water, filtered under vacuum, and dried in a vacuum drying oven at 75 °C for 24 h to obtain modified ammonium polyphosphate.

[0115] The modified ammonium polyphosphate (12 parts), melamine cyanurate (8 parts), and pentaerythritol phosphate (6 parts) were mixed evenly in a high-speed mixer to obtain the flame retardant.

[0116] Example 4

[0117] The method for preparing the thermal insulation and cold protection material provided in this embodiment includes the following steps:

[0118] 82 parts of flame-retardant modified polyolefin fiber and 18 parts of low-melting-point PET adhesive fiber are fed into a cotton blender and mixed evenly. Then, the cotton blender enters an opening machine, where mechanical force and airflow force are used to achieve initial opening and impurity removal of the fibers. After being temporarily stored in a cotton storage box, the cotton is fed into a carding machine for fiber carding and separation. Then, it is fed into a web laying machine, where the fiber material is gradually pulled out and spread into a web to obtain a fiber web. The fiber web is stacked in multiple layers and enters a heat setting unit for setting under high temperature and pressure to form fiber cotton. The fiber cotton is then trimmed by an edge trimmer and wound and packaged by a winding machine to obtain a thermal insulation and cold protection material.

[0119] The preparation method of flame-retardant modified polyolefin fiber includes the following steps:

[0120] Add 75 parts of polypropylene granules, 20 parts of polyethylene granules, 20 parts of flame retardant, 1 part of antioxidant 1010 and 1 part of calcium stearate lubricant to a high-speed mixer and mix evenly to obtain a mixture.

[0121] The mixture is added to a twin-screw extruder for melt extrusion at an extrusion temperature of 180℃ and a screw speed of 145 r / min to obtain the extruded material.

[0122] After the extruded material is metered by a metering pump, it is fed into a melt spinning machine for melt spinning. The spinning temperature is 215℃ and the spinning speed is 800m / min. The spun filaments are cooled, oiled, stretched and wound in sequence to obtain flame-retardant modified polyolefin fibers.

[0123] The preparation method of flame retardant includes the following steps:

[0124] 400 mL of ethanol and 200 mL of deionized water were mixed, and 110 g of ammonium polyphosphate was added. After thorough dispersion, ammonia was added dropwise to adjust the pH of the system to 8. Then, 22 g of dimethyldiethoxysilane and 22 g of tetraethyl orthosilicate were added. After stirring evenly, the mixture was reacted at 60 °C for 4 h with a stirring rate of 150 r / min. The mixture was then filtered, washed three times with anhydrous ethanol, washed twice with distilled water, filtered under vacuum, and dried in a vacuum drying oven at 75 °C for 24 h to obtain modified ammonium polyphosphate.

[0125] The modified ammonium polyphosphate (10 parts), melamine cyanurate (8 parts), and pentaerythritol phosphate (5 parts) were mixed evenly in a high-speed mixer to obtain the flame retardant.

[0126] Test case

[0127] The technical specifications of Example 1 described above were tested. The items, testing methods, and results are as follows:

[0128] (1) Density: Referencing GB / T 5480-2017, the length, width, and thickness of the sample in Example 1 were 301, 263, and 41 mm, respectively, with a sample mass of 33.58 g. The measured density was 10.3 kg / m³. 3 .

[0129] (2) Hydrophobicity: In accordance with GB / T 10299-2011, the samples were first pretreated and dried at 105℃ to constant weight, and then sprayed with water at a flow rate of 60L / h. After spraying for 1 hour, the hydrophobicity of the samples in the three examples 1 was 98.66%, 98.30%, and 98.32%, respectively, with an average value of 98.4%.

[0130] (3) Thermal conductivity: Refer to GB / T 10295-2008. The thermal conductivity of the four samples in Example 1 are 0.0277, 0.0310, 0.0234 and 0.0186 respectively, all in W / (m*K), with an average value of 0.025175W / (m*K).

[0131] (4) Noise reduction coefficient: Refer to GB / T 20247-2006. The size of the reverberation chamber used in the experiment was set to 9.2m*7.4m*4.8m, the temperature of the reverberation chamber was 17.5℃, and the humidity of the air field was 40%RH. The total size of the sample in Example 1 was 4960mm*1990mm*40mm, and the effective sound absorption area reached 10.36m2. After testing, the sound absorption coefficient was ≤0.49 when the test sound frequency was 100~250Hz, the sound absorption coefficient was distributed between 0.6 and 0.7 when the frequency was 315~400Hz, the sound absorption coefficient was distributed between 0.7 and 0.78 when the frequency was 400~630Hz, the sound absorption coefficient was distributed between 0.82 and 0.81 when the frequency was 800~2500Hz, and the sound absorption coefficient was distributed between 0.59 and 0.81 when the frequency was 2500~5000Hz.

[0132] (5) Moisture content: According to GB / T 16400-2015, the moisture content of the three samples of Example 1 was 0.019%, 0.063% and 0.047%, respectively, with an average value of 0.043%.

[0133] (6) Volumetric moisture absorption rate: In accordance with GB / T 5480-2017, the mass moisture absorption rate and volumetric moisture absorption rate were measured for 96 hours under the conditions of 50℃ and 95%RH. The average volumetric moisture absorption rate was calculated to be 0.007%.

[0134] (7) Fire resistance performance: The oxygen index test was conducted in accordance with GB / T 2406.2-2009 and the result was 37.1%; the flammability test was conducted in accordance with Appendix 8 of UIC564-2OR:1991 and met the Class A standard; the toxic gas analysis test was conducted in accordance with Clause 4.4 of TB / T 3237-2010 and met the clause standard.

[0135] (8) Environmental performance: The environmental performance was tested in accordance with TB / T 3139-2021 and met the relevant limits for harmful substances, prohibited substances or restricted substances in “4.8 Requirements and test methods for prohibited and restricted substances in thermal insulation materials and 5 Non-metallic materials for locomotives and rolling stock”.

[0136] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, and not to limit them; although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some or all of the technical features; and these modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present invention.

Claims

1. A thermal insulation and cold-proof material, characterized in that, Based on parts by weight, it includes the following raw materials: 80-95 parts of flame-retardant modified polyolefin fiber and 5-20 parts of low-melting-point adhesive fiber.

2. The thermal insulation and cold-proof material according to claim 1, characterized in that, The flame-retardant modified polyolefin fiber comprises, by weight parts, the following raw materials: The mixture contains 60-80 parts polypropylene, 10-20 parts polyethylene, 10-20 parts flame retardant, 0.5-1 part antioxidant, and 0.5-1 part lubricant.

3. The thermal insulation and cold-proof material according to claim 2, characterized in that, Includes at least one of the following features (1) to (3); (1) The flame retardant includes phosphorus-nitrogen flame retardants; (2) The antioxidants include antioxidant 1010; (3) The lubricant includes calcium stearate.

4. The thermal insulation and cold-proof material according to claim 3, characterized in that, The preparation method of the flame-retardant modified polyolefin fiber includes the following steps: Polypropylene, polyethylene, flame retardant, antioxidant and lubricant are mixed evenly to obtain a mixture. The mixture is sequentially melt-extruded and melt-spun to obtain filament bundles; The filament bundle is sequentially cooled, oiled, stretched, and wound to obtain the flame-retardant modified polyolefin fiber.

5. The thermal insulation and cold-proof material according to claim 4, characterized in that, The extrusion temperature of the melt extrusion is 180-220℃, and the screw speed is 100-200 r / min; And / or, the spinning temperature of the melt spinning is 220-250°C, and the spinning speed is 800-1200 m / min.

6. The thermal insulation and cold-proof material according to claim 2, characterized in that, The method for preparing the flame retardant includes the following steps: Ammonium polyphosphate was dispersed in a solution, and after adjusting the pH of the system to 7.5–8.5, dimethyldiethoxysilane and tetraethyl orthosilicate were added. After the reaction, modified ammonium polyphosphate was obtained. The modified ammonium polyphosphate, melamine cyanurate, and pentaerythritol phosphate are mixed evenly to obtain the flame retardant.

7. The thermal insulation and cold-proof material according to claim 6, characterized in that, The method for preparing the flame retardant includes at least one of the following features (1) to (3); (1) The mass ratio of the ammonium polyphosphate, the dimethyldiethoxysilane and the tetraethyl orthosilicate is (110-120):(22-25):(22-25); (2) The reaction temperature is 50-60℃ and the time is 3-4h; (3) The mass ratio of the modified ammonium polyphosphate, the melamine cyanurate and the pentaerythritol phosphate is (10-15): (8-10): (5-8).

8. The thermal insulation and cold-proofing material according to claim 1, characterized in that, The low-melting-point adhesive fiber comprises fibers mainly composed of a high-melting-point polyester core layer and a low-melting-point polyester sheath layer.

9. A method for preparing the thermal insulation and cold-proof material according to any one of claims 1 to 8, characterized in that, Includes the following steps: After the flame-retardant modified polyolefin fiber and the low-melting-point adhesive fiber are mixed evenly, they are fed into the opening machine for opening and impurity removal; then they are fed into the carding machine through the cotton storage box and the cotton feeder for carding and separation; then they are fed into the web laying machine for web laying and then shaped to form fiber cotton; the fiber cotton is then trimmed and wound to obtain the heat insulation and cold protection material.

10. The application of the thermal insulation and cold protection material according to any one of claims 1 to 8 in rail transit.