Low-temperature-resistant thermal insulation composite material and preparation method therefor

Abstract

The present invention relates to the technical field of composite materials. Disclosed in the present invention are a low-temperature-resistant thermal insulation composite material and a preparation method therefor. The material comprises an outer protective layer, an intermediate reinforcing layer, and an inner thermal insulation layer. The inner thermal insulation layer is composed of aerogel, polytetrafluoroethylene micro-powder, and the like, and provides good thermal insulation performance. The intermediate reinforcing layer contains ethylene propylene rubber and the like, and imparts elasticity, mechanical strength and flame retardancy to the material. The outer protective layer contains PVC resin and the like, and enhances the overall strength and wear resistance. A low-temperature-resistant anti-cracking additive is prepared from polyimide resin and the like, and improves crack resistance. A modified filler is prepared by means of a specific method, and improves material performance. During preparation, the layers are separately prepared and then hot-pressed for compounding. An internal mixer control system ensures the control of preparation parameters of the intermediate reinforcing layer, and uses a PID control algorithm. The composite material has a rational structural design, the layers function synergistically, and the preparation method uses mature technology. The material has excellent performance such as low-temperature resistance, thermal insulation, and crack resistance, and is suitable for various low-temperature environment applications.

Description

A low-temperature resistant thermal insulation composite material and its preparation method Technical Field

[0001] This invention relates to the field of composite material technology, specifically to a low-temperature resistant heat-insulating composite material and its preparation method. Background Technology

[0002] In numerous application fields, there is an increasing demand for low-temperature resistant insulation materials. In low-temperature environments, traditional materials often face many challenges, such as decreased insulation performance, susceptibility to cracking, and reduced mechanical strength.

[0003] In low-temperature environments, effective heat insulation is crucial. However, existing insulation materials do not perform satisfactorily at low temperatures and cannot meet the needs of some scenarios with high insulation requirements. For example, in energy transmission pipelines and cryogenic storage equipment in some cold regions, heat loss not only wastes energy but may also affect the normal operation of the equipment and the quality of stored goods.

[0004] Meanwhile, materials are prone to cracking under low-temperature conditions, which seriously affects their service life and structural integrity. When materials are subjected to low temperatures or external forces, their internal structure may change, leading to cracks, which in turn reduces the material's performance and may even cause safety hazards.

[0005] Furthermore, the overall performance of traditional materials needs improvement, including mechanical strength and wear resistance. In practical applications, materials need to possess good mechanical strength to withstand certain pressures and external forces, while wear resistance is related to the surface quality and performance stability of the material during long-term use.

[0006] Therefore, developing a composite material with excellent low-temperature resistance, good thermal insulation, and strong crack resistance, while also possessing good mechanical strength and wear resistance, has become an important research direction and urgent need in the field of materials science. Such a material will have broad application prospects in many fields such as cryogenic engineering, energy, and chemical engineering, and can solve many problems existing in current materials under low-temperature conditions, improving the performance and reliability of related equipment and engineering projects. Summary of the Invention

[0007] To achieve the above objectives, the present invention is implemented through the following technical solution: a low-temperature resistant heat-insulating composite material, comprising an outer protective layer, an intermediate reinforcing layer, and an inner heat-insulating layer;

[0008] The inner insulation layer comprises the following components by weight:

[0009] 3-5 parts by weight of aerogel, 70-80 parts by weight of polytetrafluoroethylene micro powder, 8-10 parts by weight of hollow glass microspheres, 9-11 parts by weight of azodicarbonamide, and 7-8 parts by weight of nano talc.

[0010] The intermediate reinforcement layer comprises the following weight components:

[0011] 11-13 parts by weight of ethylene propylene rubber, 6-7 parts by weight of polystyrene, 30-35 parts by weight of aluminum hydroxide, 3-4 parts by weight of antimony trioxide, and 15-18 parts by weight of chlorinated paraffin;

[0012] The outer protective layer comprises the following components by weight:

[0013] The composition includes 85-90 parts by weight of PVC resin, 7-9 parts by weight of wear-resistant filler, 18-22 parts by weight of modified filler, 25-26 parts by weight of ethylene-vinyl acetate copolymer, 4-8 parts by weight of composite heat stabilizer, 2.5-4 parts by weight of dispersant, 1.3-2.2 parts by weight of lubricant, 4.5-5.5 parts by weight of mixed silane coupling agent, 2-4 parts by weight of plasticizer, 2.3-3.6 parts by weight of antioxidant, 4.5-4.8 parts by weight of compatibilizer, and 12-15 parts by weight of low-temperature resistant anti-cracking additive.

[0014] Specifically, the wear-resistant filler is silicon carbide micro powder, the modified filler is nano-calcium carbonate, the composite heat stabilizer is calcium-zinc composite heat stabilizer, the dispersant is polyethylene wax dispersant, the lubricant is calcium stearate, the mixed silane coupling agent is KH-560 mixed silane coupling agent, the plasticizer is dioctyl phthalate, the antioxidant is antioxidant 1010, and the compatibilizer is maleic anhydride-grafted polypropylene.

[0015] The specific preparation method of the low-temperature resistant and crack-resistant additive is as follows:

[0016] Step 1: Add polyimide resin, polyetheretherketone resin and silicone rubber to the reactor, heat and mix at high speed. Add nano-silica and glass fiber to the reactor and mix to obtain matrix A.

[0017] Step 2: Add polydimethylsiloxane to matrix A, heat and mix, then turn on ultrasonic dispersion and stir to mix;

[0018] Step 3: Add antioxidants and ultraviolet absorbers to the reaction vessel, heat and stir to obtain a low-temperature resistant and crack-resistant additive.

[0019] Preferably, the low-temperature resistant crack-resistant additive is composed of the following parts by weight: 1-3 parts of polyimide resin, 2-4 parts of polyetheretherketone resin, 1-2 parts of silicone rubber, 2-3 parts of nano silica, 1-1.5 parts of glass fiber, 1-1.8 parts of polydimethylsiloxane, 0.5-0.8 parts of antioxidant, and 0.5-1 parts of ultraviolet absorber.

[0020] The use of low-temperature resistant crack-resistant additives effectively improves the crack resistance of composite materials. Materials such as polyimide resin, polyetheretherketone resin, and silicone rubber possess good flexibility and adhesion, preventing cracks from forming when the material is exposed to low temperatures or external forces.

[0021] Preferably, the specific preparation method of the modified filler is as follows:

[0022] A1. Pour toluene into a reaction vessel and heat to 80-82℃. The amount of toluene is twice the total volume of the reactants. Dissolve the initiator benzoyl peroxide in toluene. The amount of initiator is usually 1.5% of the total mass of the monomers.

[0023] A2. Mix methyl methacrylate, butyl acrylate, styrene, crosslinking agent and functional monomer hydroxyethyl methacrylate evenly. After mixing, add the mixture dropwise into the reaction vessel and maintain the temperature to carry out the reaction.

[0024] A3. After the reaction is complete, cool to room temperature, pour the product into methanol for precipitation, filtration and drying. The amount of methanol used is 3 times that of the reaction system to obtain polymer filler B.

[0025] A4. Dry the nano-calcium carbonate and nano-titanium dioxide, with a ratio of 1:2. Add the dried nano-calcium carbonate and nano-titanium dioxide to a high-speed mixer, along with silane coupling agent KH-550, stearic acid, and polyethylene glycol 4000. Mix and stir, with the silane coupling agent KH-550, stearic acid, and polyethylene glycol 4000 accounting for 1.5% of the total mass. Then add polymer filler B, with a mass ratio of polymer filler B to nano-calcium carbonate and nano-titanium dioxide of 1:1. Continue mixing and stirring until the filler surface is fully covered by the treatment agent and the new polymer material.

[0026] Among them, the chemical name of the silane coupling agent KH-550 is γ-aminopropyltriethoxysilane, and its CAS number is 919-30-2;

[0027] A5. After mixing, remove the surface-treated material from the high-speed mixer and cool it to room temperature to obtain the modified filler.

[0028] Preferably, the crosslinking agent in step A2 is divinylbenzene, and the weight ratio of methyl methacrylate, butyl acrylate, styrene, crosslinking agent and functional monomer hydroxyethyl methacrylate is 40:30:20:1:1:3.

[0029] Preferably, the temperature of the reactor in step A2 is 79-81°C.

[0030] Preferably, the specific preparation method of the ethylene-vinyl acetate copolymer is as follows:

[0031] C1. Mix 75-85% by mass of ethylene and 15-25% by mass of vinyl acetate, and then put them into a high-pressure reactor equipped with a stirring device. The pressure of the reactor is controlled at 150-250 MPa and the temperature is controlled at 200-250℃.

[0032] C2. Add an initiator to the reactor and polymerize for 5-10 hours. After the reaction is complete, cool the reaction solution to room temperature, then pour the polymer solution into methanol to precipitate the precipitate. After filtration, washing and drying, ethylene-vinyl acetate copolymer is obtained.

[0033] This composite material employs a multi-layered structure design consisting of an outer protective layer, a middle reinforcing layer, and an inner insulating layer. Each layer works synergistically to leverage its individual advantages, thereby improving the overall performance of the material. This structural design can be adjusted and optimized to meet different application requirements, offering high flexibility and adaptability.

[0034] By rationally combining and preparing materials such as polyimide resin, polyetheretherketone resin, silicone rubber, nano-silica, glass fiber, polydimethylsiloxane, antioxidants, and ultraviolet absorbers, an additive with excellent low-temperature resistance and crack resistance was obtained. This effectively improves the overall performance of the composite material and provides new ideas and methods for the development of low-temperature insulation materials.

[0035] A modified filler with excellent properties was prepared by mixing nano-calcium carbonate, nano-titanium dioxide, silane coupling agent, stearic acid, polyethylene glycol 4000, and novel polymer materials. This improved the mechanical strength, wear resistance, and processability of the composite material, providing a new approach for material performance optimization.

[0036] A method for preparing a low-temperature resistant thermal insulation composite material includes the following preparation steps:

[0037] S1. Preparation of the inner insulation layer: Aerogel, polytetrafluoroethylene micro powder, hollow glass microspheres, azodicarbonamide and nano talc powder are added to a high-speed mixer and mixed evenly. Under a pressure of 5-10MPa and a temperature controlled at 150-200℃, the inner insulation layer is obtained by hot pressing.

[0038] The synergistic effect of materials such as aerogel, polytetrafluoroethylene micropowder, and hollow glass microspheres in the inner insulation layer provides excellent thermal insulation performance, reduces heat transfer, and enables the material to maintain good performance even at low temperatures.

[0039] Aerogels have extremely low thermal conductivity, effectively preventing heat transfer. The addition of hollow glass microspheres and azodicarbonamide further improves the material's thermal insulation properties and reduces its thermal conductivity.

[0040] S2. Preparation of intermediate reinforcing layer: Ethylene propylene rubber, polystyrene, aluminum hydroxide, antimony trioxide, and chlorinated paraffin are added to a mixer for mixing. The mixed material is extruded and formed by an extruder, and the intermediate reinforcing layer is obtained after cooling.

[0041] Ethylene propylene rubber (EPR) in the intermediate reinforcing layer imparts elasticity and low-temperature resistance to the material, ensuring that the composite material does not become brittle at low temperatures and maintains structural integrity. Materials such as polystyrene, aluminum hydroxide, antimony trioxide, and chlorinated paraffin in the intermediate reinforcing layer improve the mechanical strength and flame retardant properties of the composite material.

[0042] S3. Preparation of outer protective layer: PVC resin, wear-resistant filler, modified filler, ethylene-vinyl acetate copolymer, composite heat stabilizer, dispersant, lubricant, mixed silane coupling agent, plasticizer, antioxidant, compatibilizer and low temperature crack-resistant additive are added to a high-speed mixer. The mixed material is extruded and molded through an extruder to obtain the outer protective layer.

[0043] The PVC resin, wear-resistant fillers, and various additives in the outer protective layer also enhance the overall strength and wear resistance of the material.

[0044] The preparation method of this composite material includes the separate preparation of the inner insulation layer, the intermediate reinforcement layer, and the outer protective layer, and finally the bonding of the three layers together by hot pressing. This preparation method is mature, easy to operate, and can ensure the quality and performance stability of the material.

[0045] The compatibilizer can be either maleic anhydride-grafted ethylene-vinyl acetate copolymer or acrylate-maleic anhydride copolymer. This compatibilizer can effectively improve the compatibility between different materials, enhance the interfacial bonding force of composite materials, and improve the overall performance of the materials.

[0046] S4. Stack the inner insulation layer, the middle reinforcement layer and the outer protective layer in sequence, put them into a hot press, control the pressure at 10-15MPa and the temperature at 180-220℃ for hot pressing composite, and obtain the low temperature resistant heat insulation composite material.

[0047] Preferably, the internal mixer control system in step S2 consists of a temperature control module, a speed control module, a time control module, and a feeding control module, which are used to realize parameter control during the mixing process of the internal mixer;

[0048] The temperature control module includes a temperature sensor, a heating device, and a cooling device. The temperature sensor is installed on the wall of the mixing chamber and is used to monitor the temperature in real time and convert the signal.

[0049] The speed control module consists of a controller and a servo motor. The controller adjusts the speed of the servo motor according to the preset process and operation instructions.

[0050] The time control module includes a timer, which controls the mixing process according to set time parameters.

[0051] The feeding control module is used to control the feeding device to feed materials according to a preset sequence logic, and to monitor the feeding amount through sensors.

[0052] Preferably, the temperature control module adopts a PID control algorithm, which adjusts the output power of the heating and cooling devices based on the deviation between the temperature feedback from the temperature sensor and the preset temperature setting.

[0053] The specific calculation formula for the PID control algorithm is as follows:

[0054]

[0055] in For PID control output value, For integral coefficients, For differential coefficients, For the proportionality coefficient and Temperature deviation;

[0056] The The calculation formula is:

[0057]

[0058] in For preset temperature setting value and The temperature signal of the mixing chamber is collected in real time by a temperature sensor.

[0059] Preferably, the operation steps of the internal mixer are as follows:

[0060] D1. Start the internal mixer control system and input the process parameters, stage speed requirements, mixing time and feeding data;

[0061] D2. First, the temperature control module starts the heating device to preheat. The controller adjusts the heating power according to the preset algorithm until the initial temperature rises to the preset value.

[0062] D3. According to the preset feeding sequence, the controller opens the corresponding feeding devices in sequence to add the materials into the mixing chamber;

[0063] D4. After the feeding is completed, the internal mixer enters the mixing stage to internally mix the materials;

[0064] D5. After the mixing is completed, open the discharge valve of the mixer to discharge the mixed rubber compound.

[0065] This invention provides a low-temperature resistant thermal insulation composite material and its preparation method. It has the following beneficial effects:

[0066] I. This low-temperature resistant thermal insulation composite material and its preparation method effectively improve the crack resistance of the composite material through the use of low-temperature resistant and crack-resistant additives. The polyimide resin, polyetheretherketone resin, and silicone rubber contained therein possess good flexibility and adhesion. The high elasticity and good extensibility of silicone rubber compensate for the shortcomings in elasticity of polyimide resin and polyetheretherketone resin. The combined effect of these three materials allows the additives to form a network structure with good flexibility and adhesion in the composite material, preventing cracks from forming when the material is at low temperatures or under external force.

[0067] II. The low-temperature resistant thermal insulation composite material and its preparation method: This composite material adopts a multi-layered composite structure design consisting of an outer protective layer, a middle reinforcing layer, and an inner thermal insulation layer. Each layer works synergistically to leverage its respective advantages, thereby improving the overall performance of the material. This structural design can be adjusted and optimized according to different application requirements, exhibiting high flexibility and adaptability.

[0068] By rationally combining and preparing materials such as polyimide resin, polyetheretherketone resin, silicone rubber, nano-silica, glass fiber, polydimethylsiloxane, antioxidants, and ultraviolet absorbers, the overall performance of composite materials is effectively improved.

[0069] A modified filler with excellent properties was prepared by mixing nano-calcium carbonate, nano-titanium dioxide, silane coupling agent, stearic acid, polyethylene glycol 4000, and novel polymer materials. This improved the mechanical strength, wear resistance, and processability of the composite material, providing a new approach for material performance optimization.

[0070] The silane coupling agent KH-550 hydrolyzes to generate silanol groups, which can undergo condensation reactions with hydroxyl groups on the surface of nano-calcium carbonate and nano-titanium dioxide to form strong chemical bonds.

[0071] III. The low-temperature resistant heat insulation composite material and its preparation method provide good heat insulation performance through the synergistic effect of materials such as aerogel, polytetrafluoroethylene micro powder and hollow glass microspheres in the inner heat insulation layer, reduce heat transfer, and enable the material to maintain good performance in low-temperature environments.

[0072] Aerogels have extremely low thermal conductivity, effectively preventing heat transfer. The addition of hollow glass microspheres and azodicarbonamide further improves the material's thermal insulation properties and reduces its thermal conductivity.

[0073] When aerogel works synergistically with polytetrafluoroethylene (PTFE) microparticles and hollow glass microspheres, its nanoporous structure can be nested within the PTFE microparticles and hollow glass microspheres at the microscopic level. PTFE microparticles can fill some of the tiny pores in the aerogel, further hindering heat transfer through air convection within the pores. The combination of aerogel and hollow glass microspheres forms a multi-layered insulating structure, requiring heat to pass through multiple obstacles, including reflection from the hollow glass microspheres, convection suppression by the aerogel's nanopores, and solid-state heat conduction, thus significantly reducing heat transfer efficiency.

[0074] IV. This low-temperature resistant thermal insulation composite material and its preparation method utilize ethylene propylene rubber in the intermediate reinforcing layer to impart elasticity and low-temperature resistance to the material, ensuring that the composite material does not become brittle at low temperatures and maintains structural integrity. Materials such as polystyrene, aluminum hydroxide, antimony trioxide, and chlorinated paraffin in the intermediate reinforcing layer improve the mechanical strength and flame retardant properties of the composite material. Detailed Implementation

[0075] The present invention will now be described in further detail with reference to specific embodiments. The embodiments of the present invention are given for illustrative and descriptive purposes only, and are not intended to be exhaustive or to limit the invention to the disclosed forms. Many modifications and variations will be apparent to those skilled in the art. The embodiments were chosen and described to better illustrate the principles and practical application of the invention, and to enable those skilled in the art to understand the invention and design various embodiments with various modifications suitable for a particular purpose.

[0076] Example 1: The present invention provides a technical solution:

[0077] A method for preparing a low-temperature resistant thermal insulation composite material includes the following preparation steps:

[0078] S1. Preparation of the inner insulation layer: Aerogel, polytetrafluoroethylene micro powder, hollow glass microspheres, azodicarbonamide and nano talc powder are added to a high-speed mixer and mixed evenly. Under a pressure of 8MPa and a temperature controlled at 175℃, the inner insulation layer is obtained by hot pressing.

[0079] S2. Preparation of intermediate reinforcing layer: Ethylene propylene rubber, polystyrene, aluminum hydroxide, antimony trioxide, and chlorinated paraffin are added to a mixer for mixing. The mixed material is extruded and formed by an extruder, and the intermediate reinforcing layer is obtained after cooling.

[0080] The internal mixer control system consists of a temperature control module, a speed control module, a time control module, and a feeding control module, which are used to control parameters during the mixing process of the internal mixer.

[0081] The temperature control module includes a temperature sensor, a heating device, and a cooling device. The temperature sensor is installed on the wall of the mixing chamber and is used to monitor the temperature in real time and convert the signal.

[0082] The temperature control module uses a PID control algorithm to adjust the output power of the heating and cooling devices based on the deviation between the temperature feedback from the temperature sensor and the preset temperature setting.

[0083] The specific operating steps of the internal mixer are as follows:

[0084] D1. Start the internal mixer control system and input the process parameters, stage speed requirements, mixing time and feeding data;

[0085] D2. First, the temperature control module starts the heating device to preheat. The controller adjusts the heating power according to the preset algorithm until the initial temperature rises to the preset value.

[0086] D3. According to the preset feeding sequence, the controller opens the corresponding feeding devices in sequence to add the materials into the mixing chamber;

[0087] D4. After the feeding is completed, the internal mixer enters the mixing stage to internally mix the materials;

[0088] D5. After the mixing is completed, open the discharge valve of the mixer to discharge the mixed rubber compound.

[0089] The speed control module consists of a controller and a servo motor. The controller adjusts the speed of the servo motor according to the preset process and operation instructions.

[0090] The time control module includes a timer, which controls the mixing process according to set time parameters.

[0091] The feeding control module is used to control the feeding device to feed materials according to a preset sequence logic, and to monitor the feeding amount through sensors.

[0092] S3. Preparation of outer protective layer: PVC resin, wear-resistant filler, modified filler, ethylene-vinyl acetate copolymer, composite heat stabilizer, dispersant, lubricant, mixed silane coupling agent, plasticizer, antioxidant, compatibilizer and low temperature crack-resistant additive are added to a high-speed mixer. The mixed material is extruded and molded through an extruder to obtain the outer protective layer.

[0093] The compatibilizer can be either maleic anhydride-grafted ethylene-vinyl acetate copolymer or acrylate-maleic anhydride copolymer;

[0094] S4. Stack the inner insulation layer, the middle reinforcement layer and the outer protective layer in sequence, put them into a hot press, and perform hot pressing composite at a pressure of 12.3MPa and a temperature of 183.7℃ to obtain a low-temperature resistant heat insulation composite material.

[0095] Example 2: Based on Example 1, the present invention provides a technical solution:

[0096] A low-temperature resistant thermal insulation composite material includes an outer protective layer, an intermediate reinforcing layer, and an inner thermal insulation layer;

[0097] The inner insulation layer comprises the following components by weight:

[0098] 3 parts by weight of aerogel, 70 parts by weight of polytetrafluoroethylene micro powder, 8 parts by weight of hollow glass microspheres, 9 parts by weight of azodicarbonamide, and 7 parts by weight of nano talc.

[0099] The intermediate reinforcement layer comprises the following weight components:

[0100] 11 parts by weight of ethylene propylene rubber, 6 parts by weight of polystyrene, 30 parts by weight of aluminum hydroxide, 3 parts by weight of antimony trioxide, and 15 parts by weight of chlorinated paraffin;

[0101] The outer protective layer comprises the following components by weight:

[0102] The composition includes 85 parts by weight of PVC resin, 7 parts by weight of wear-resistant filler, 18 parts by weight of modified filler, 25 parts by weight of ethylene-vinyl acetate copolymer, 4 parts by weight of composite heat stabilizer, 2.5 parts by weight of dispersant, 1.3 parts by weight of lubricant, 4.5 parts by weight of mixed silane coupling agent, 2 parts by weight of plasticizer, 2.3 parts by weight of antioxidant, 4.5 parts by weight of compatibilizer, and 12 parts by weight of low-temperature resistant crack-resistant additive.

[0103] The specific preparation method of the ethylene-vinyl acetate copolymer is as follows:

[0104] C1. Mix 75% ethylene and 15% vinyl acetate by mass and place them in a high-pressure reactor equipped with a stirrer. The reactor pressure is controlled at 150 MPa and the temperature is controlled at 200℃.

[0105] C2. Add an initiator to the reactor and polymerize for 5 hours. After the reaction is complete, cool the reaction solution to room temperature, then pour the polymer solution into methanol to precipitate the precipitate. After filtration, washing and drying, ethylene-vinyl acetate copolymer is obtained.

[0106] The specific preparation method of the modified filler is as follows:

[0107] A1. Pour toluene into a reaction vessel and heat to 80°C to dissolve the initiator benzoyl peroxide in toluene;

[0108] A2. Mix methyl methacrylate, butyl acrylate, styrene, crosslinking agent and functional monomer hydroxyethyl methacrylate evenly. After mixing, add the mixture dropwise into the reaction vessel. The temperature of the reaction vessel is 79°C. Maintain the temperature to carry out the reaction.

[0109] The crosslinking agent is divinylbenzene, and the weight ratio of methyl methacrylate, butyl acrylate, styrene, crosslinking agent, and functional monomer hydroxyethyl methacrylate is 40:30:20:1:1:3.

[0110] A3. After the reaction is complete, cool to room temperature, pour the product into methanol to precipitate, filter and dry to obtain polymer filler B;

[0111] A4. Dry the nano-calcium carbonate and nano-titanium dioxide. Add the dried nano-calcium carbonate and nano-titanium dioxide to a high-speed mixer. Add silane coupling agent KH-550, stearic acid and polyethylene glycol 4000 and mix. Then add polymer filler B and continue mixing until the filler surface is fully covered by the treatment agent and the new polymer material.

[0112] A5. After mixing, remove the surface-treated material from the high-speed mixer and cool it to room temperature to obtain the modified filler.

[0113] The low-temperature resistant and crack-resistant additive is composed of the following parts by weight: 1-3 parts polyimide resin, 2 parts polyetheretherketone resin, 1 part silicone rubber, 2 parts nano silica, 1 part glass fiber, 1 part polydimethylsiloxane, 0.5 parts antioxidant, and 0.5 parts ultraviolet absorber.

[0114] The specific preparation method of the low-temperature resistant and crack-resistant additive is as follows:

[0115] Step 1: Add polyimide resin, polyetheretherketone resin and silicone rubber to the reactor, heat and mix at high speed. Add nano-silica and glass fiber to the reactor and mix to obtain matrix A.

[0116] Step 2: Add polydimethylsiloxane to matrix A, heat and mix, then turn on ultrasonic dispersion and stir to mix;

[0117] Step 3: Add antioxidants and ultraviolet absorbers to the reaction vessel, heat and stir to obtain a low-temperature resistant and crack-resistant additive.

[0118] Example 3: Based on Example 1, the present invention provides a technical solution:

[0119] A low-temperature resistant thermal insulation composite material includes an outer protective layer, an intermediate reinforcing layer, and an inner thermal insulation layer;

[0120] The inner insulation layer comprises the following components by weight:

[0121] 5 parts by weight of aerogel, 80 parts by weight of polytetrafluoroethylene micro powder, 10 parts by weight of hollow glass microspheres, 11 parts by weight of azodicarbonamide, and 8 parts by weight of nano talc.

[0122] The intermediate reinforcement layer comprises the following weight components:

[0123] 13 parts by weight of ethylene propylene rubber, 7 parts by weight of polystyrene, 35 parts by weight of aluminum hydroxide, 4 parts by weight of antimony trioxide, and 18 parts by weight of chlorinated paraffin;

[0124] The outer protective layer comprises the following components by weight:

[0125] The composition includes 90 parts by weight of PVC resin, 9 parts by weight of wear-resistant filler, 22 parts by weight of modified filler, 26 parts by weight of ethylene-vinyl acetate copolymer, 8 parts by weight of composite heat stabilizer, 4 parts by weight of dispersant, 2.2 parts by weight of lubricant, 5.5 parts by weight of mixed silane coupling agent, 4 parts by weight of plasticizer, 3.6 parts by weight of antioxidant, 4.8 parts by weight of compatibilizer, and 15 parts by weight of low-temperature resistant crack-resistant additive.

[0126] The specific preparation method of the ethylene-vinyl acetate copolymer is as follows:

[0127] C1. Mix 85% by mass of ethylene and 25% by mass of vinyl acetate and place them in a high-pressure reactor equipped with a stirrer. The reactor pressure is controlled at 250 MPa and the temperature is controlled at 250 °C.

[0128] C2. Add an initiator to the reactor and polymerize for 10 hours. After the reaction is complete, cool the reaction solution to room temperature, then pour the polymer solution into methanol to precipitate the precipitate. After filtration, washing and drying, ethylene-vinyl acetate copolymer is obtained.

[0129] The specific preparation method of the modified filler is as follows:

[0130] A1. Pour toluene into a reaction vessel and heat to 82°C to dissolve the initiator benzoyl peroxide in toluene;

[0131] A2. Mix methyl methacrylate, butyl acrylate, styrene, crosslinking agent and functional monomer hydroxyethyl methacrylate evenly. After mixing, add the mixture dropwise into the reaction vessel. The temperature of the reaction vessel is 81℃. Maintain the temperature to carry out the reaction.

[0132] The crosslinking agent is divinylbenzene, and the weight ratio of methyl methacrylate, butyl acrylate, styrene, crosslinking agent, and functional monomer hydroxyethyl methacrylate is 40:30:20:1:1:3.

[0133] A3. After the reaction is complete, cool to room temperature, pour the product into methanol to precipitate, filter and dry to obtain polymer filler B;

[0134] A4. Dry the nano-calcium carbonate and nano-titanium dioxide. Add the dried nano-calcium carbonate and nano-titanium dioxide to a high-speed mixer. Add silane coupling agent KH-550, stearic acid and polyethylene glycol 4000 and mix. Then add polymer filler B and continue mixing until the filler surface is fully covered by the treatment agent and the new polymer material.

[0135] A5. After mixing, remove the surface-treated material from the high-speed mixer and cool it to room temperature to obtain the modified filler.

[0136] The low-temperature resistant and crack-resistant additive is composed of the following parts by weight: 3 parts polyimide resin, 4 parts polyetheretherketone resin, 2 parts silicone rubber, 3 parts nano silica, 1.5 parts glass fiber, 1.8 parts polydimethylsiloxane, 0.8 parts antioxidant, and 1 part ultraviolet absorber.

[0137] The specific preparation method of the low-temperature resistant and crack-resistant additive is as follows:

[0138] Step 1: Add polyimide resin, polyetheretherketone resin and silicone rubber to the reactor, heat and mix at high speed. Add nano-silica and glass fiber to the reactor and mix to obtain matrix A.

[0139] Step 2: Add polydimethylsiloxane to matrix A, heat and mix, then turn on ultrasonic dispersion and stir to mix;

[0140] Step 3: Add antioxidants and ultraviolet absorbers to the reaction vessel, heat and stir to obtain a low-temperature resistant and crack-resistant additive.

[0141] Example 4: Based on Example 1, the present invention provides a technical solution:

[0142] A low-temperature resistant thermal insulation composite material includes an outer protective layer, an intermediate reinforcing layer, and an inner thermal insulation layer;

[0143] The inner insulation layer comprises the following components by weight:

[0144] 3.5 parts by weight of aerogel, 72.5 parts by weight of polytetrafluoroethylene micro powder, 9.4 parts by weight of hollow glass microspheres, 10.25 parts by weight of azodicarbonamide and 7.5 parts by weight of nano talc;

[0145] The intermediate reinforcement layer comprises the following weight components:

[0146] 11 parts by weight of ethylene propylene rubber, 6.5 parts by weight of polystyrene, 35 parts by weight of aluminum hydroxide, 3 parts by weight of antimony trioxide, and 15.5 parts by weight of chlorinated paraffin;

[0147] The outer protective layer comprises the following components by weight:

[0148] The composition includes 90 parts by weight of PVC resin, 8.5 parts by weight of wear-resistant filler, 20 parts by weight of modified filler, 25.6 parts by weight of ethylene-vinyl acetate copolymer, 4.78 parts by weight of composite heat stabilizer, 3 parts by weight of dispersant, 1.5 parts by weight of lubricant, 5 parts by weight of mixed silane coupling agent, 3 parts by weight of plasticizer, 2.85 parts by weight of antioxidant, 4.6 parts by weight of compatibilizer, and 12.5 parts by weight of low-temperature resistant crack-resistant additive.

[0149] The specific preparation method of the ethylene-vinyl acetate copolymer is as follows:

[0150] C1. Mix 85% ethylene and 15% vinyl acetate by mass and place them in a high-pressure reactor equipped with a stirrer. The reactor pressure is controlled at 250 MPa and the temperature is controlled at 250 °C.

[0151] C2. Add an initiator to the reactor and polymerize for 10 hours. After the reaction is complete, cool the reaction solution to room temperature, then pour the polymer solution into methanol to precipitate the precipitate. After filtration, washing and drying, ethylene-vinyl acetate copolymer is obtained.

[0152] The specific preparation method of the modified filler is as follows:

[0153] A1. Pour toluene into a reaction vessel and heat to 82°C to dissolve the initiator benzoyl peroxide in toluene;

[0154] A2. Mix methyl methacrylate, butyl acrylate, styrene, crosslinking agent and functional monomer hydroxyethyl methacrylate evenly. After mixing, add the mixture dropwise into the reaction vessel. The temperature of the reaction vessel is 80℃. Maintain the temperature to carry out the reaction.

[0155] The crosslinking agent is divinylbenzene, and the weight ratio of methyl methacrylate, butyl acrylate, styrene, crosslinking agent, and functional monomer hydroxyethyl methacrylate is 40:30:20:1:1:3.

[0156] A3. After the reaction is complete, cool to room temperature, pour the product into methanol to precipitate, filter and dry to obtain polymer filler B;

[0157] A4. Dry the nano-calcium carbonate and nano-titanium dioxide. Add the dried nano-calcium carbonate and nano-titanium dioxide to a high-speed mixer. Add silane coupling agent KH-550, stearic acid and polyethylene glycol 4000 and mix. Then add polymer filler B and continue mixing until the filler surface is fully covered by the treatment agent and the new polymer material.

[0158] A5. After mixing, remove the surface-treated material from the high-speed mixer and cool it to room temperature to obtain the modified filler.

[0159] The low-temperature resistant and crack-resistant additive is composed of the following parts by weight: 2 parts polyimide resin, 3 parts polyetheretherketone resin, 1.5 parts silicone rubber, 2.5 parts nano silica, 1.25 parts glass fiber, 1.4 parts polydimethylsiloxane, 0.6 parts antioxidant, and 0.6 parts ultraviolet absorber.

[0160] The specific preparation method of the low-temperature resistant and crack-resistant additive is as follows:

[0161] Step 1: Add polyimide resin, polyetheretherketone resin and silicone rubber to the reactor, heat and mix at high speed. Add nano-silica and glass fiber to the reactor and mix to obtain matrix A.

[0162] Step 2: Add polydimethylsiloxane to matrix A, heat and mix, then turn on ultrasonic dispersion and stir to mix;

[0163] Step 3: Add antioxidants and ultraviolet absorbers to the reaction vessel, heat and stir to obtain a low-temperature resistant and crack-resistant additive.

[0164] Comparative Example 1: Based on Example 4, the low-temperature resistant crack-preventing additive was removed, while the remaining components and preparation methods were the same as in Example 4.

[0165] Comparative Example 2: Based on Example 4, the ethylene-vinyl acetate copolymer was removed, while the remaining components and preparation methods were the same as in Example 4;

[0166] Performance testing:

[0167] 1. Overview of the test sample;

[0168] The low-temperature resistant thermal insulation composite material tested in this study included five samples: Example 2, Example 3, Example 4, Comparative Example 1, and Comparative Example 2.

[0169] Each sample consists of an outer protective layer, a middle reinforcing layer, and an inner insulation layer.

[0170] 2. Test items and methods;

[0171] (1) Thermal insulation performance test;

[0172] Test method: Steady-state heat flow method was used, and the test was conducted according to GB / T10294-2008 standard.

[0173] Test procedure: Place the 300mm×300mm×25mm sample between the hot and cold plates of the thermal conductivity meter, adjust it to close contact, set the temperature difference to 25°C, and after stabilization, measure the heat flow to calculate the thermal conductivity. Measure each sample 3 times and take the average.

[0174] (2) Low-temperature impact performance test;

[0175] Test method: The test shall be conducted in accordance with the GB / T1043.1-2008 standard.

[0176] Test procedure: Process the composite material into standard notched specimens and place them in a low temperature chamber. Set the temperature to -60°C and -80°C for 3 hours. Remove the specimens and place them on the support of the impact testing machine. Impact them with the specified pendulum and record the impact absorption energy. Measure each sample 3 times at each temperature and take the average.

[0177] (3) Low-temperature resistance test;

[0178] Test procedure: Cut a 120mm×30mm sample and place it in a -50°C low temperature chamber for 5 hours. Take it out and place it in a bending fixture. Bend it with a radius of 6mm and apply a tensile force of 50N. Observe the cracking situation (no, slight, moderate, severe).

[0179] 3. Test results and analysis;

[0180] (1) Thermal insulation performance test results

[0181] Thermal conductivity of samples (W / (m·K)): Example 2 0.023; Example 3 0.017; Example 4 0.022; Comparative Example 1 0.038; Comparative Example 2 0.03

[0182] Analysis: The thermal conductivity of the example is lower than that of the comparative example. Due to the combination of inner layer materials, the thermal conductivity of example three is the lowest.

[0183] (2) Low-temperature impact performance test results

[0184] Sample impact absorption energy (J) (-60°C) Impact absorption energy (J) (-80°C) Example 2 7.5 5.0 Example 3 9.0 6.5 Example 4 8.0 5.5 Comparative Example 1 4.5 2.5 Comparative Example 2 5.0 3.0

[0185] Analysis: Under low-temperature shock, the energy of the example was higher than that of the comparative example, with example three being particularly outstanding;

[0186] (3) Cracking resistance test results

[0187] Samples: No cracking, slight cracking, moderate cracking, severe cracking. Example 2: 30%, 40%, 20%, 10%. Example 3: 60%, 20%, 15%, 5%. Example 4: 40%, 35%, 18%, 7%. Comparative Example 1: 10%, 20%, 40%, 30%. Comparative Example 2: 15%, 25%, 35%, 25%.

[0188] Analysis: The crack resistance of the examples is better than that of the comparative examples, and Example 3 is the best;

[0189] 4. Conclusion

[0190] Based on the tests conducted on the thermal insulation performance, low-temperature impact performance, and crack resistance of the low-temperature resistant thermal insulation composite material of the present invention in Examples 2, 3, and 4, as well as Comparative Examples 1 and 2, the following conclusions can be drawn:

[0191] (1) With the application of low-temperature resistant and crack-resistant additives, the composite material of the present invention has significantly improved thermal insulation performance, low-temperature impact performance and crack resistance.

[0192] (2) The application of ethylene-vinyl acetate copolymer can improve the flexibility and impact resistance of composite materials.

[0193] Obviously, the described embodiments are only a part of the embodiments of the present invention, and not all of them. All other embodiments obtained by those skilled in the art and related fields based on the embodiments of the present invention without inventive effort should fall within the scope of protection of the present invention. Structures, devices, and operating methods not specifically described and explained in the present invention, unless otherwise specified or limited, shall be implemented according to conventional means in the art.

Claims

1. A low temperature resistant thermal insulation composite material, characterized in that: It includes an outer protective layer, a middle reinforcing layer, and an inner insulation layer; The inner insulation layer comprises the following components by weight: 3-5 parts by weight of aerogel, 70-80 parts by weight of polytetrafluoroethylene micro powder, 8-10 parts by weight of hollow glass microspheres, 9-11 parts by weight of azodicarbonamide, and 7-8 parts by weight of nano talc. The intermediate reinforcement layer comprises the following weight components: 11-13 parts by weight of ethylene propylene rubber, 6-7 parts by weight of polystyrene, 30-35 parts by weight of aluminum hydroxide, 3-4 parts by weight of antimony trioxide, and 15-18 parts by weight of chlorinated paraffin; The outer protective layer comprises the following components by weight: The composition includes 85-90 parts by weight of PVC resin, 7-9 parts by weight of wear-resistant filler, 18-22 parts by weight of modified filler, 25-26 parts by weight of ethylene-vinyl acetate copolymer, 4-8 parts by weight of composite heat stabilizer, 2.5-4 parts by weight of dispersant, 1.3-2.2 parts by weight of lubricant, 4.5-5.5 parts by weight of mixed silane coupling agent, 2-4 parts by weight of plasticizer, 2.3-3.6 parts by weight of antioxidant, 4.5-4.8 parts by weight of compatibilizer, and 12-15 parts by weight of low-temperature resistant anti-cracking additive. The specific preparation method of the low-temperature resistant and crack-resistant additive is as follows: Step 1: Add polyimide resin, polyetheretherketone resin and silicone rubber to the reactor, heat and mix at high speed. Add nano-silica and glass fiber to the reactor and mix to obtain matrix A. Step 2: Add polydimethylsiloxane to matrix A, heat and mix, then turn on ultrasonic dispersion and stir to mix; Step 3: Add antioxidants and ultraviolet absorbers to the reaction vessel, heat and stir to obtain a low-temperature resistant and crack-resistant additive.

2. The low temperature resistant thermal insulation composite material according to claim 1, characterized in that: The low-temperature resistant and crack-resistant additive is composed of the following parts by weight: 1-3 parts polyimide resin, 2-4 parts polyetheretherketone resin, 1-2 parts silicone rubber, 2-3 parts nano silica, 1-1.5 parts glass fiber, 1-1.8 parts polydimethylsiloxane, 0.5-0.8 parts antioxidant, and 0.5-1 part ultraviolet absorber.

3. The low temperature resistant thermal insulation composite material of claim 1, wherein: The specific preparation method of the modified filler is as follows: A1. Pour toluene into a reaction vessel and heat to 80-82℃ to dissolve the initiator benzoyl peroxide in toluene; A2. Mix methyl methacrylate, butyl acrylate, styrene, crosslinking agent and functional monomer hydroxyethyl methacrylate evenly. After mixing, add the mixture dropwise into the reaction vessel and maintain the temperature to carry out the reaction. A3. After the reaction is complete, cool to room temperature, pour the product into methanol to precipitate, filter and dry to obtain polymer filler B; A4. Dry the nano-calcium carbonate and nano-titanium dioxide. Add the dried nano-calcium carbonate and nano-titanium dioxide to a high-speed mixer. Add silane coupling agent KH-550, stearic acid and polyethylene glycol 4000 and mix. Then add polymer filler B and continue mixing until the filler surface is fully covered by the treatment agent and the new polymer material. A5. After mixing, remove the surface-treated material from the high-speed mixer and cool it to room temperature to obtain the modified filler.

4. The low temperature resistant thermal insulation composite material according to claim 3, characterized in that: The crosslinking agent in step A2 is divinylbenzene, and the weight ratio of methyl methacrylate, butyl acrylate, styrene, crosslinking agent and functional monomer hydroxyethyl methacrylate is 40:30:20:1:1:

3.

5. The cryogenically resistant thermal insulation composite of claim 3, wherein: The temperature of the reactor in step A2 is 79-81℃.

6. The cryogenically resistant thermal insulation composite of claim 1, wherein: The specific preparation method of the ethylene-vinyl acetate copolymer is as follows: C1. Mix 75-85% by mass of ethylene and 15-25% by mass of vinyl acetate, and then put them into a high-pressure reactor equipped with a stirring device. The pressure of the reactor is controlled at 150-250 MPa and the temperature is controlled at 200-250℃. C2. Add an initiator to the reactor and polymerize for 5-10 hours. After the reaction is complete, cool the reaction solution to room temperature, then pour the polymer solution into methanol to precipitate the precipitate. After filtration, washing and drying, ethylene-vinyl acetate copolymer is obtained.

7. A method of making a low temperature resistant thermal insulation composite material, characterized in that, The preparation steps include the following: S1. Preparation of the inner insulation layer: Aerogel, polytetrafluoroethylene micro powder, hollow glass microspheres, azodicarbonamide and nano talc powder are added to a high-speed mixer and mixed evenly. Under a pressure of 5-10MPa and a temperature controlled at 150-200℃, the inner insulation layer is obtained by hot pressing. S2. Preparation of intermediate reinforcing layer: Ethylene propylene rubber, polystyrene, aluminum hydroxide, antimony trioxide, and chlorinated paraffin are added to a mixer for mixing. The mixed material is extruded and formed by an extruder, and the intermediate reinforcing layer is obtained after cooling. S3. Preparation of outer protective layer: PVC resin, wear-resistant filler, modified filler, ethylene-vinyl acetate copolymer, composite heat stabilizer, dispersant, lubricant, mixed silane coupling agent, plasticizer, antioxidant, compatibilizer and low temperature crack-resistant additive are added to a high-speed mixer. The mixed material is extruded and molded through an extruder to obtain the outer protective layer. The compatibilizer can be either maleic anhydride-grafted ethylene-vinyl acetate copolymer or acrylate-maleic anhydride copolymer; S4. Stack the inner insulation layer, the middle reinforcement layer and the outer protective layer in sequence, put them into a hot press, control the pressure at 10-15MPa and the temperature at 180-220℃ for hot pressing composite, and obtain the low temperature resistant heat insulation composite material.

8. The method for preparing a low-temperature resistant thermal insulation composite material according to claim 7, characterized in that, The internal mixer control system in step S2 consists of a temperature control module, a speed control module, a time control module, and a feeding control module, which are used to control parameters during the mixing process of the internal mixer. The temperature control module includes a temperature sensor, a heating device, and a cooling device. The temperature sensor is installed on the wall of the mixing chamber and is used to monitor the temperature in real time and convert the signal. The speed control module consists of a controller and a servo motor. The controller adjusts the speed of the servo motor according to the preset process and operation instructions. The time control module includes a timer, which controls the mixing process according to set time parameters. The feeding control module is used to control the feeding device to feed materials according to a preset sequence logic, and to monitor the feeding amount through sensors.

9. The method of claim 8, wherein the method further comprises: The temperature control module uses a PID control algorithm to adjust the output power of the heating and cooling devices based on the deviation between the temperature feedback from the temperature sensor and the preset temperature setting.

10. The method of claim 9, wherein the method further comprises: The specific operating steps of the internal mixer are as follows: D1. Start the internal mixer control system and input the process parameters, stage speed requirements, mixing time and feeding data; D2. First, the temperature control module starts the heating device to preheat. The controller adjusts the heating power according to the preset algorithm until the initial temperature rises to the preset value. D3. According to the preset feeding sequence, the controller opens the corresponding feeding devices in sequence to add the materials into the mixing chamber; D4. After the feeding is completed, the internal mixer enters the mixing stage to internally mix the materials. D5. After the internal mixing is completed, open the discharge valve of the internal mixer to discharge the mixed rubber compound.

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