A low temperature resistant heat insulating composite material and preparation method thereof

Abstract

The invention discloses a low-temperature resistant heat-insulating composite material and a preparation method thereof, and the invention relates to the technical field of composite materials. The material comprises an outer protective layer, an intermediate reinforcement layer and an inner heat-insulating layer. The inner heat-insulating layer is composed of aerogel, polytetrafluoroethylene micropowder, etc., and provides good heat-insulating performance. The intermediate reinforcement layer contains ethylene-propylene rubber, etc., which gives the material elasticity, mechanical strength and flame retardancy. The outer protective layer has PVC resin, etc., which enhances the overall strength and wear resistance. The low-temperature resistant anti-cracking additive is prepared from polyimide resin, etc., to improve the anti-cracking performance. The modified filler is prepared by a specific method to improve the material performance. During the preparation, each layer is prepared separately and then hot-pressed and compounded. The internal mixer control system ensures the control of the preparation parameters of the intermediate reinforcement layer, and adopts the PID control algorithm. The composite material has a reasonable structural design, the synergistic effect of each layer, and the preparation method is mature. It has excellent properties such as low-temperature resistance, heat insulation, and crack resistance, and is suitable for a variety of low-temperature environment applications.

Description

Technical Field

[0001] The invention relates to the technical field of composite materials, in particular to a low-temperature resistant heat-insulating composite material and a preparation method thereof. Background Art

[0002] In many 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 reduced insulation performance, easy cracking, and reduced mechanical strength.

[0003] In low-temperature environments, effective heat insulation is crucial, but the existing insulation materials are not satisfactory at low temperatures and cannot meet some scenarios with high insulation requirements. For example, in energy transmission pipelines and low-temperature storage equipment in some cold regions, heat loss will not only cause energy waste, but may also affect the normal operation of the equipment and the quality of stored items.

[0004] At the same time, the material is prone to cracking under low temperature conditions, which seriously affects the service life and structural integrity of the material. When the material is affected by low temperature or external force, its internal structure may change, leading to cracks, which in turn reduces the performance of the material and may even cause safety hazards.

[0005] In addition, the comprehensive performance of traditional materials needs to be improved, including mechanical strength, wear resistance, etc. In practical applications, materials need to have good mechanical strength to withstand certain pressure 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 effect and strong crack resistance, as well as good mechanical strength and wear resistance, has become an important research direction and urgent need in the current materials field. This material will have broad application prospects in many fields such as cryogenic engineering, energy, and chemical industry, and can solve many problems existing in existing materials in low temperature environments and improve the performance and reliability of related equipment and engineering. Summary of the invention

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

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

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

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

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

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

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

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

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

[0016] Step 1: Add polyimide resin, polyetheretherketone resin and silicone rubber into a reaction kettle, heat and mix at high speed, the heating time is 50 minutes, the heating temperature is 85° C., add nano-silicon dioxide and glass fiber into the reaction kettle, and mix to obtain matrix A;

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

[0018] Step 3: adding an antioxidant and an ultraviolet absorber into a reaction kettle, heating and stirring to obtain a low-temperature resistant anti-cracking additive.

[0019] Preferably, the low-temperature resistant and anti-cracking 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-silicon dioxide, 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 anti-cracking additives effectively improves the anti-cracking performance of composite materials. Among them, polyimide resin, polyetheretherketone resin, silicone rubber and other materials have good flexibility and adhesion, which can prevent the material from cracking at low temperatures or under external forces.

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

[0022] A1. Pour toluene into a reaction kettle and heat it to 80-82° C. The amount of toluene is 120 parts by mass. Dissolve the initiator dibenzoyl peroxide in toluene. The amount of the initiator dibenzoyl peroxide is 10 parts by mass.

[0023] A2, methyl methacrylate, butyl acrylate, styrene, a crosslinking agent and a functional monomer hydroxyethyl methacrylate were mixed evenly, and the mixture was added dropwise to a reaction kettle, and the temperature was maintained at 80 degrees Celsius for reaction;

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

[0025] A4, drying the nano calcium carbonate and nano titanium dioxide, wherein the dried nano calcium carbonate and nano titanium dioxide are added to a high-speed mixer, and silane coupling agent KH-550, stearic acid and polyethylene glycol 4000 are added and mixed and stirred, wherein the silane coupling agent KH-550, stearic acid and polyethylene glycol 4000 are 1.5% of the total mass, and then polymer filler B is added, wherein the mass ratio of polymer filler B: nano calcium carbonate and nano titanium dioxide is 1:1, and the mixing and stirring are continued, and the surface of the filler is fully covered by the treatment agent silane coupling agent KH-550, stearic acid and polyethylene glycol 4000 and the polymer filler B to end the mixing;

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

[0027] A5. After the mixing is completed, the surface treated material is taken out from the high-speed mixer and cooled to room temperature to obtain a modified filler.

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

[0029] Preferably, the specific preparation method of the ethylene-vinyl acetate copolymer is as follows:

[0030] C1. Mix 75-85% by mass of ethylene and 15-25% by mass of vinyl acetate, and put them into a high-pressure reactor with a stirring device. The pressure of the reactor is controlled at 150-250 MPa and the temperature is controlled at 200-250°C.

[0031] C2. Add 10 parts by mass of dibenzoyl peroxide as an initiator into a reactor, and carry out polymerization reaction for 5-10 hours. After the reaction, cool the reaction solution to room temperature, and then pour the polymer solution into methanol to precipitate. After filtering, washing and drying, ethylene-vinyl acetate copolymer is obtained.

[0032] The composite material adopts a multi-layer composite structure design with an outer protective layer, an intermediate reinforcement layer and an inner insulation layer. Each layer cooperates with each other, giving full play to their respective advantages and improving the comprehensive performance of the material. This structural design can be adjusted and optimized according to different application requirements, with high flexibility and adaptability.

[0033] By rationally combining and preparing materials such as polyimide resin, polyetheretherketone resin, silicone rubber, nano-silicon dioxide, glass fiber, polydimethylsiloxane, antioxidant and ultraviolet absorber, an additive with excellent low temperature resistance and anti-cracking performance was obtained. It effectively improves the overall performance of the composite material and provides new ideas and methods for the development of low temperature resistant insulation materials.

[0034] A modified filler with good performance was prepared by mixing nano calcium carbonate, nano titanium dioxide, silane coupling agent, stearic acid, polyethylene glycol 4000 and new polymer materials. The mechanical strength, wear resistance and processing performance of the composite material were improved, providing a new way to optimize the performance of the material.

[0035] A method for preparing a low-temperature resistant heat-insulating composite material comprises the following preparation steps:

[0036] S1, preparation of inner thermal insulation layer, adding aerogel, polytetrafluoroethylene powder, hollow glass microspheres, azodicarbonamide and nano talc into a high-speed mixer, mixing evenly, and hot pressing to obtain inner thermal insulation layer at a pressure of 5-10 MPa and a temperature of 150-200° C., the hot pressing time being 1-2 hours;

[0037] The synergistic effect of materials such as aerogel, polytetrafluoroethylene powder and hollow glass microspheres in the inner insulation layer provides good thermal insulation performance, reduces heat transfer, and enables the material to maintain good performance in low temperature environments.

[0038] Aerogel has extremely low thermal conductivity and can effectively prevent heat transfer. The addition of hollow glass microspheres and azodicarbonamide further improves the thermal insulation performance of the material and reduces the thermal conductivity.

[0039] S2, preparation of the middle reinforcement layer, adding ethylene propylene rubber, polyphenylene ester, aluminum hydroxide, antimony trioxide, and chlorinated paraffin materials into an internal mixer for mixing, the mixing temperature is 120-200° C., the mixing time is 2 hours, the mixed materials are extruded through an extruder, and the middle reinforcement layer is obtained after cooling to room temperature;

[0040] The EPDM rubber in the middle reinforcement layer gives the material elasticity and low temperature resistance, ensuring that the composite material will not become brittle at low temperatures and maintain the integrity of the structure. Materials such as polyphenylene ester, aluminum hydroxide, antimony trioxide and chlorinated paraffin in the middle reinforcement layer improve the mechanical strength and flame retardant properties of the composite material.

[0041] S3, preparation of outer protective layer, adding 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 resistant anti-cracking additive into a high-speed mixer, the mixing time is 1 hour, and the mixed materials are extruded by an extruder to obtain an outer protective layer;

[0042] 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.

[0043] The preparation method of the composite material includes the preparation of the inner insulation layer, the middle reinforcement layer and the outer protective layer respectively, and finally combining 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.

[0044] The compatibilizer is any one of maleic anhydride grafted ethylene-vinyl acetate copolymer and acrylate-maleic anhydride copolymer. This compatibilizer can effectively improve the compatibility between different materials, enhance the interface bonding force of the composite material, and improve the overall performance of the material.

[0045] S4. Stack the inner insulation layer, the middle reinforcement layer and the outer protection layer in sequence, put them into a hot press, control the pressure at 10-15MPa, and control the temperature at 180-220°C for hot pressing and compounding for 30 minutes to obtain a low-temperature resistant thermal insulation composite material.

[0046] Preferably, the internal mixer control system in step S2 is composed 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;

[0047] Wherein, the temperature control module includes a temperature sensor, a heating device and a cooling device, and the temperature sensor is installed on the wall of the mixing chamber to monitor the temperature in real time and convert the signal;

[0048] The speed control module is composed of a controller and a servo motor, and the controller adjusts the speed of the servo motor according to a preset process and an operation instruction;

[0049] The time control module includes a timer, and the time control module performs timing control on mixing according to the set time parameters;

[0050] The feeding control module is used to control the feeding device to feed materials according to a preset sequence logic, and monitor the feeding amount through a sensor.

[0051] Preferably, the temperature control module adopts a PID control algorithm to adjust the output power of the heating device and the cooling device based on the deviation between the temperature feedback from the temperature sensor and a preset temperature setting value.

[0052] The specific calculation formula of the PID control algorithm is:

[0053]

[0054] in is the PID control output value, is the integral coefficient, is the differential coefficient, is the proportionality factor and is the temperature deviation;

[0055] Said The calculation formula is:

[0056]

[0057] in For preset temperature setpoints and It is the temperature signal of the mixing chamber collected in real time by the temperature sensor.

[0058] Preferably, the operation steps of the internal mixer are specifically as follows:

[0059] D1. Start the internal mixer control system and input process parameters, stage speed requirements, mixing time and feeding data;

[0060] D2. First, the temperature control module starts the heating device for preheating, and the controller adjusts the heating power according to the preset algorithm until the initial temperature rises to the preset value;

[0061] D3. According to the preset feeding sequence, the controller opens the corresponding feeding devices in sequence and adds the materials into the mixing chamber;

[0062] D4. After the addition is completed, the internal mixer enters the mixing stage to mix the materials;

[0063] D5. After the internal mixing is completed, open the discharge valve of the internal mixer to discharge the mixed rubber material.

[0064] The present invention provides a low temperature resistant heat insulation composite material and a preparation method thereof. It has the following beneficial effects:

[0065] 1. The low-temperature resistant thermal insulation composite material and its preparation method effectively improve the anti-cracking performance of the composite material by using the low-temperature resistant anti-cracking additive. The polyimide resin, polyetheretherketone resin, silicone rubber and other materials have good flexibility and adhesion, and the high elasticity and good elasticity of silicone rubber make up for the deficiencies of polyimide resin and polyetheretherketone resin in elasticity; the three work together to make the additive form a network structure with good flexibility and adhesion in the composite material, which can prevent the material from cracking at low temperature or under the action of external force.

[0066] Second, the low-temperature resistant heat-insulating composite material and its preparation method, through the composite material adopting the multi-layer composite structure design of outer protective layer, middle reinforcement layer and inner heat-insulating layer, each layer cooperates with each other, exerts their own advantages, and improves the comprehensive performance of the material. This structural design can be adjusted and optimized according to different application requirements, with high flexibility and adaptability;

[0067] The overall performance of the composite material is effectively improved by rationally combining and preparing materials such as polyimide resin, polyetheretherketone resin, silicone rubber, nano-silicon dioxide, glass fiber, polydimethylsiloxane, antioxidant and ultraviolet absorber.

[0068] By mixing nano calcium carbonate, nano titanium dioxide, silane coupling agent, stearic acid, polyethylene glycol 4000 and new polymer materials, a modified filler with good performance was obtained. The mechanical strength, wear resistance and processing performance of the composite material were improved, providing a new way to optimize the performance of the material;

[0069] The silane alkoxy groups in the silane coupling agent KH-550 are hydrolyzed to generate silanol groups, which can undergo condensation reactions with the hydroxyl groups on the surfaces of nano-calcium carbonate and nano-titanium dioxide to form strong chemical bonds.

[0070] 3. The low-temperature resistant heat-insulating composite material and its preparation method provide good heat-insulating performance and reduce heat transfer through the synergistic effect of materials such as aerogel, polytetrafluoroethylene powder and hollow glass microspheres in the inner heat-insulating layer, so that the material can still maintain good performance in a low-temperature environment and can well insulate the temperature of about minus fifty degrees;

[0071] Aerogel has extremely low thermal conductivity and can effectively prevent heat transfer. The addition of hollow glass microspheres and azodicarbonamide further improves the thermal insulation performance of the material and reduces the thermal conductivity coefficient;

[0072] When aerogel works with polytetrafluoroethylene powder and hollow glass microspheres, its nanoporous structure can be nested with polytetrafluoroethylene powder and hollow glass microspheres at the microscopic level. Polytetrafluoroethylene powder can fill some of the tiny pores of aerogel, further hindering the transfer of heat through air convection in the pores; the combination of aerogel and hollow glass microspheres forms a multi-level insulation structure, and heat needs to pass through multiple obstacles such as reflection of hollow glass microspheres, convection inhibition of aerogel nanopores, and solid-state heat conduction in turn, thereby greatly reducing the efficiency of heat transfer.

[0073] Fourth, the low-temperature resistant heat-insulating composite material and its preparation method give the material elasticity and low-temperature resistance through EPDM in the middle reinforcement layer, ensuring that the composite material will not become brittle at low temperatures and maintain the integrity of the structure. The materials such as polyphenyl ester, aluminum hydroxide, antimony trioxide and chlorinated paraffin in the middle reinforcement layer improve the mechanical strength and flame retardant properties of the composite material. DETAILED DESCRIPTION

[0074] The present invention will be further described in detail below in conjunction with specific embodiments. The embodiments of the present invention are provided for the purpose of illustration and description, and are not intended to be exhaustive or to limit the present invention to the disclosed forms. Many modifications and variations will be apparent to those of ordinary skill in the art. The embodiments are selected and described to better illustrate the principles and practical applications of the present invention, and to enable those of ordinary skill in the art to understand the present invention and thereby design various embodiments with various modifications suitable for specific uses.

[0075] Embodiment 1, the present invention provides a technical solution:

[0076] A method for preparing a low-temperature resistant heat-insulating composite material comprises the following preparation steps:

[0077] S1, preparation of inner thermal insulation layer, adding aerogel, polytetrafluoroethylene powder, hollow glass microspheres, azodicarbonamide and nano talc into a high-speed mixer, mixing evenly, and then hot pressing to obtain inner thermal insulation layer under a pressure of 8 MPa and a temperature of 175°C, the hot pressing time being 1-2 hours;

[0078] S2, preparation of the middle reinforcement layer, adding ethylene propylene rubber, polyphenylene ester, aluminum hydroxide, antimony trioxide, and chlorinated paraffin materials into an internal mixer for mixing, the mixing temperature is 120-200° C., the mixing time is 2 hours, the mixed materials are extruded through an extruder, and the middle reinforcement layer is obtained after cooling to room temperature;

[0079] 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 realize parameter control during the mixing process of the internal mixer;

[0080] Wherein, the temperature control module includes a temperature sensor, a heating device and a cooling device, and the temperature sensor is installed on the wall of the mixing chamber to monitor the temperature in real time and convert the signal;

[0081] The temperature control module adopts PID control algorithm to adjust the output power of the heating device and the cooling device based on the deviation between the temperature feedback from the temperature sensor and the preset temperature setting value.

[0082] The operating steps of the internal mixer are specifically as follows:

[0083] D1. Start the internal mixer control system and input process parameters, stage speed requirements, mixing time and feeding data;

[0084] D2. First, the temperature control module starts the heating device for preheating, and the controller adjusts the heating power according to the preset algorithm until the initial temperature rises to the preset value;

[0085] D3. According to the preset feeding sequence, the controller opens the corresponding feeding devices in sequence and adds the materials into the mixing chamber;

[0086] D4. After the addition is completed, the internal mixer enters the mixing stage to mix the materials;

[0087] D5. After the internal mixing is completed, open the discharge valve of the internal mixer to discharge the mixed rubber material.

[0088] The speed control module is composed of a controller and a servo motor, and the controller adjusts the speed of the servo motor according to a preset process and an operation instruction;

[0089] The time control module includes a timer, and the time control module performs timing control on mixing according to the set time parameters;

[0090] The feeding control module is used to control the feeding device to feed materials according to a preset sequence logic, and monitor the feeding amount through a sensor.

[0091] S3, preparation of outer protective layer, adding 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 resistant anti-cracking additive into a high-speed mixer, the mixing time is 1 hour, and the mixed materials are extruded by an extruder to obtain an outer protective layer;

[0092] The compatibilizer is any one of maleic anhydride grafted ethylene-vinyl acetate copolymer and acrylate-maleic anhydride copolymer;

[0093] S4. Stack the inner insulation layer, the middle reinforcement layer and the outer protection layer in sequence, put them into a hot press, control the pressure at 12.3 MPa, and control the temperature at 183.7°C for hot pressing and compounding. The hot pressing and compounding time is 30 minutes to obtain a low-temperature resistant thermal insulation composite material.

[0094] Embodiment 2: Based on Embodiment 1, the present invention provides a technical solution:

[0095] A low temperature resistant heat insulation composite material, comprising an outer protective layer, an intermediate reinforcement layer and an inner heat insulation layer;

[0096] Wherein, the inner insulation layer comprises the following components by weight:

[0097] 3 parts by mass of aerogel, 70 parts by mass of polytetrafluoroethylene powder, 8 parts by mass of hollow glass microspheres, 9 parts by mass of azodicarbonamide and 7 parts by mass of nano-talc;

[0098] The intermediate reinforcement layer comprises the following weight components:

[0099] 11 parts by mass of ethylene propylene rubber, 6 parts by mass of polyphenylene ester, 30 parts by mass of aluminum hydroxide, 3 parts by mass of antimony trioxide and 15 parts by mass of chlorinated paraffin;

[0100] The outer protective layer comprises the following components by weight:

[0101] 85 parts by mass of PVC resin, 7 parts by mass of wear-resistant filler, 18 parts by mass of modified filler, 25 parts by mass of ethylene-vinyl acetate copolymer, 4 parts by mass of composite heat stabilizer, 2.5 parts by mass of dispersant, 1.3 parts by mass of lubricant, 4.5 parts by mass of mixed silane coupling agent, 2 parts by mass of plasticizer, 2.3 parts by mass of antioxidant, 4.5 parts by mass of compatibilizer and 12 parts by mass of low temperature resistant anti-cracking additive;

[0102] The specific preparation method of the ethylene-vinyl acetate copolymer is as follows:

[0103] C1. Mix 75% by mass of ethylene and 15% by mass of vinyl acetate, and put them into a high-pressure reactor with a stirring device. The pressure of the reactor is controlled at 150 MPa and the temperature is controlled at 200°C.

[0104] C2. Add 10 parts by mass of dibenzoyl peroxide as an initiator into a reactor and carry out polymerization reaction for 5 hours. After the reaction, cool the reaction solution to room temperature, pour the polymer solution into methanol, precipitate, filter, wash and dry to obtain ethylene-vinyl acetate copolymer.

[0105] The specific preparation method of the modified filler is as follows:

[0106] A1. Pour toluene into a reaction kettle and heat it to 80°C. The amount of toluene is 120 parts by mass. Dissolve the initiator dibenzoyl peroxide in toluene. The amount of the initiator dibenzoyl peroxide is 10 parts by mass.

[0107] A2, methyl methacrylate, butyl acrylate, styrene, a crosslinking agent and a functional monomer hydroxyethyl methacrylate were mixed evenly, and the mixture was added dropwise to a reaction kettle, and the temperature was maintained at 80 degrees Celsius for reaction;

[0108] The cross-linking agent is divinylbenzene, and the weight ratio of methyl methacrylate, butyl acrylate, styrene, cross-linking agent and functional monomer hydroxyethyl methacrylate is 40:30:20:1:1:3;

[0109] A3. After the reaction is completed, the mixture is cooled to room temperature, and the product is poured into methanol for precipitation, filtered and dried to obtain polymer filler B;

[0110] A4, the nano calcium carbonate and nano titanium dioxide are dried, the dried nano calcium carbonate and nano titanium dioxide are added to a high-speed mixer, silane coupling agent KH-550, stearic acid and polyethylene glycol 4000 are added and mixed, and then polymer filler B is added, and mixing is continued, and the filler surface is fully covered by the treatment agent silane coupling agent KH-550, stearic acid and polyethylene glycol 4000 and the polymer filler B to finish mixing;

[0111] A5. After the mixing is completed, the surface treated material is taken out from the high-speed mixer and cooled to room temperature to obtain a modified filler.

[0112] The low temperature resistant anti-cracking additive is composed of the following parts by weight: 1-3 parts of polyimide resin, 2 parts of polyetheretherketone resin, 1 part of silicone rubber, 2 parts of nano silicon dioxide, 1 part of glass fiber, 1 part of polydimethylsiloxane, 0.5 parts of antioxidant, and 0.5 parts of ultraviolet absorber;

[0113] The specific preparation method of the low temperature resistant anti-cracking additive is as follows:

[0114] Step 1: Add polyimide resin, polyetheretherketone resin and silicone rubber into a reaction kettle, heat and mix at high speed, the heating time is 50 minutes, the heating temperature is 85° C., add nano-silicon dioxide and glass fiber into the reaction kettle, and mix to obtain matrix A;

[0115] Step 2: Add polydimethylsiloxane to matrix A, heat and mix, start ultrasonic dispersion, and then stir and mix;

[0116] Step 3: adding an antioxidant and an ultraviolet absorber into a reaction kettle, heating and stirring to obtain a low-temperature resistant anti-cracking additive.

[0117] Embodiment 3, based on embodiment 1, the present invention provides a technical solution:

[0118] A low temperature resistant heat insulation composite material, comprising an outer protective layer, an intermediate reinforcement layer and an inner heat insulation layer;

[0119] Wherein, the inner insulation layer comprises the following components by weight:

[0120] 5 parts by mass of aerogel, 80 parts by mass of polytetrafluoroethylene powder, 10 parts by mass of hollow glass microspheres, 11 parts by mass of azodicarbonamide and 8 parts by mass of nano talc;

[0121] The intermediate reinforcement layer comprises the following weight components:

[0122] 13 parts by mass of ethylene propylene rubber, 7 parts by mass of polyphenylene ester, 35 parts by mass of aluminum hydroxide, 4 parts by mass of antimony trioxide and 18 parts by mass of chlorinated paraffin;

[0123] The outer protective layer comprises the following components by weight:

[0124] 90 parts by mass of PVC resin, 9 parts by mass of wear-resistant filler, 22 parts by mass of modified filler, 26 parts by mass of ethylene-vinyl acetate copolymer, 8 parts by mass of composite heat stabilizer, 4 parts by mass of dispersant, 2.2 parts by mass of lubricant, 5.5 parts by mass of mixed silane coupling agent, 4 parts by mass of plasticizer, 3.6 parts by mass of antioxidant, 4.8 parts by mass of compatibilizer and 15 parts by mass of low temperature resistant anti-cracking additive;

[0125] The specific preparation method of the ethylene-vinyl acetate copolymer is as follows:

[0126] C1. Mix 85% by mass of ethylene and 25% by mass of vinyl acetate, and put them into a high-pressure reactor with a stirring device. The pressure of the reactor is controlled at 250 MPa and the temperature is controlled at 250°C;

[0127] C2. Add 10 parts by mass of dibenzoyl peroxide as an initiator into a reactor and carry out polymerization reaction for 10 hours. After the reaction, cool the reaction solution to room temperature, pour the polymer solution into methanol, precipitate, filter, wash and dry to obtain ethylene-vinyl acetate copolymer.

[0128] The specific preparation method of the modified filler is as follows:

[0129] A1. Pour toluene into a reaction kettle and heat it to 82° C. The amount of toluene is 120 parts by mass. Dissolve the initiator dibenzoyl peroxide in toluene. The amount of the initiator dibenzoyl peroxide is 10 parts by mass.

[0130] A2, methyl methacrylate, butyl acrylate, styrene, a crosslinking agent and a functional monomer hydroxyethyl methacrylate were mixed evenly, and the mixture was added dropwise to a reaction kettle, and the temperature was maintained at 80 degrees Celsius for reaction;

[0131] The cross-linking agent is divinylbenzene, and the weight ratio of methyl methacrylate, butyl acrylate, styrene, cross-linking agent and functional monomer hydroxyethyl methacrylate is 40:30:20:1:1:3;

[0132] A3. After the reaction is completed, the mixture is cooled to room temperature, and the product is poured into methanol for precipitation, filtered and dried to obtain polymer filler B;

[0133] A4, the nano calcium carbonate and nano titanium dioxide are dried, the dried nano calcium carbonate and nano titanium dioxide are added to a high-speed mixer, silane coupling agent KH-550, stearic acid and polyethylene glycol 4000 are added and mixed, and then polymer filler B is added, and mixing is continued, and the filler surface is fully covered by the treatment agent silane coupling agent KH-550, stearic acid and polyethylene glycol 4000 and the polymer filler B to finish mixing;

[0134] A5. After the mixing is completed, the surface treated material is taken out from the high-speed mixer and cooled to room temperature to obtain a modified filler.

[0135] The low temperature resistant anti-cracking additive is composed of the following parts by weight: 3 parts of polyimide resin, 4 parts of polyetheretherketone resin, 2 parts of silicone rubber, 3 parts of nano silicon dioxide, 1.5 parts of glass fiber, 1.8 parts of polydimethylsiloxane, 0.8 parts of antioxidant, and 1 part of ultraviolet absorber;

[0136] The specific preparation method of the low temperature resistant anti-cracking additive is as follows:

[0137] Step 1: Add polyimide resin, polyetheretherketone resin and silicone rubber into a reaction kettle, heat and mix at high speed, the heating time is 50 minutes, the heating temperature is 85° C., add nano-silicon dioxide and glass fiber into the reaction kettle, and mix to obtain matrix A;

[0138] Step 2: Add polydimethylsiloxane to matrix A, heat and mix, start ultrasonic dispersion, and then stir and mix;

[0139] Step 3: adding an antioxidant and an ultraviolet absorber into a reaction kettle, heating and stirring to obtain a low-temperature resistant anti-cracking additive.

[0140] Embodiment 4: Based on Embodiment 1, the present invention provides a technical solution:

[0141] A low temperature resistant heat insulation composite material, comprising an outer protective layer, an intermediate reinforcement layer and an inner heat insulation layer;

[0142] Wherein, the inner insulation layer comprises the following components by weight:

[0143] 3.5 parts by mass of aerogel, 72.5 parts by mass of polytetrafluoroethylene powder, 9.4 parts by mass of hollow glass microspheres, 10.25 parts by mass of azodicarbonamide and 7.5 parts by mass of nano-talc;

[0144] The intermediate reinforcement layer comprises the following weight components:

[0145] 11 parts by mass of ethylene propylene rubber, 6.5 parts by mass of polyphenylene ester, 35 parts by mass of aluminum hydroxide, 3 parts by mass of antimony trioxide and 15.5 parts by mass of chlorinated paraffin;

[0146] The outer protective layer comprises the following components by weight:

[0147] 90 parts by mass of PVC resin, 8.5 parts by mass of wear-resistant filler, 20 parts by mass of modified filler, 25.6 parts by mass of ethylene-vinyl acetate copolymer, 4.78 parts by mass of composite heat stabilizer, 3 parts by mass of dispersant, 1.5 parts by mass of lubricant, 5 parts by mass of mixed silane coupling agent, 3 parts by mass of plasticizer, 2.85 parts by mass of antioxidant, 4.6 parts by mass of compatibilizer and 12.5 parts by mass of low temperature resistant anti-cracking additive;

[0148] The specific preparation method of the ethylene-vinyl acetate copolymer is as follows:

[0149] C1. Mix 85% by mass of ethylene and 15% by mass of vinyl acetate, and put them into a high-pressure reactor with a stirring device. The pressure of the reactor is controlled at 250 MPa and the temperature is controlled at 250°C.

[0150] C2. Add 10 parts by mass of dibenzoyl peroxide as an initiator into a reactor and carry out polymerization reaction for 10 hours. After the reaction, cool the reaction solution to room temperature, pour the polymer solution into methanol, precipitate, filter, wash and dry to obtain ethylene-vinyl acetate copolymer.

[0151] The specific preparation method of the modified filler is as follows:

[0152] A1. Pour toluene into a reaction kettle and heat it to 82° C. The amount of toluene is 120 parts by mass. Dissolve the initiator dibenzoyl peroxide in toluene. The amount of the initiator dibenzoyl peroxide is 10 parts by mass.

[0153] A2, methyl methacrylate, butyl acrylate, styrene, a crosslinking agent and a functional monomer hydroxyethyl methacrylate were mixed evenly, and the mixture was added dropwise to a reaction kettle, and the temperature was maintained at 80 degrees Celsius for reaction;

[0154] The cross-linking agent is divinylbenzene, and the weight ratio of methyl methacrylate, butyl acrylate, styrene, cross-linking agent and functional monomer hydroxyethyl methacrylate is 40:30:20:1:1:3;

[0155] A3. After the reaction is completed, the mixture is cooled to room temperature, and the product is poured into methanol for precipitation, filtered and dried to obtain polymer filler B;

[0156] A4, the nano calcium carbonate and nano titanium dioxide are dried, the dried nano calcium carbonate and nano titanium dioxide are added to a high-speed mixer, silane coupling agent KH-550, stearic acid and polyethylene glycol 4000 are added and mixed, and then polymer filler B is added, and mixing is continued, and the filler surface is fully covered by the treatment agent silane coupling agent KH-550, stearic acid and polyethylene glycol 4000 and the polymer filler B to finish mixing;

[0157] A5. After the mixing is completed, the surface treated material is taken out from the high-speed mixer and cooled to room temperature to obtain a modified filler.

[0158] The low temperature resistant anti-cracking additive is composed of the following parts by weight: 2 parts of polyimide resin, 3 parts of polyetheretherketone resin, 1.5 parts of silicone rubber, 2.5 parts of nano silicon dioxide, 1.25 parts of glass fiber, 1.4 parts of polydimethylsiloxane, 0.6 parts of antioxidant, and 0.6 parts of ultraviolet absorber;

[0159] The specific preparation method of the low temperature resistant anti-cracking additive is as follows:

[0160] Step 1: Add polyimide resin, polyetheretherketone resin and silicone rubber into a reaction kettle, heat and mix at high speed, the heating time is 50 minutes, the heating temperature is 85° C., add nano-silicon dioxide and glass fiber into the reaction kettle, and mix to obtain matrix A;

[0161] Step 2: Add polydimethylsiloxane to matrix A, heat and mix, start ultrasonic dispersion, and then stir and mix;

[0162] Step 3: adding an antioxidant and an ultraviolet absorber into a reaction kettle, heating and stirring to obtain a low-temperature resistant anti-cracking additive.

[0163] Comparative Example 1: Based on Example 4, the low-temperature resistant and anti-cracking additive is removed, and the remaining components and preparation method are the same as those of Example 4;

[0164] Comparative Example 2: Based on Example 4, ethylene-vinyl acetate copolymer was removed, and the remaining components and preparation methods were the same as those of Example 4;

[0165] Performance Test:

[0166] 1. Overview of test samples;

[0167] The low-temperature resistant thermal insulation composite materials tested in this test include five samples, namely, Example 2, Example 3, Example 4, Comparative Example 1 and Comparative Example 2;

[0168] Each sample consists of an outer protective layer, a middle reinforcement layer and an inner insulation layer.

[0169] 2. Test items and methods;

[0170] (1) Thermal insulation performance test;

[0171] Test method: Steady-state heat flow method is used to test according to GB / T10294-2008 standard.

[0172] Test steps: Place a 300mm×300mm×25mm sample between the hot and cold plates of the thermal conductivity tester, adjust them to close contact, set the temperature difference to 25°C, measure the heat flow and calculate the thermal conductivity after stabilization, measure each sample 3 times and take the average.

[0173] (2) Low temperature impact performance test;

[0174] Test method: Test in accordance with GB / T1043.1-2008 standard.

[0175] Test steps: Process the composite material into a standard notch specimen and place it in a low temperature box, set the temperature at -60°C and -80°C for 3 hours, take it out and place it on the support of the impact tester, impact it with a specified pendulum, record the impact absorption energy, measure each sample 3 times at each temperature and take the average.

[0176] (3) Low temperature resistance test;

[0177] Test steps: Cut a 120mm×30mm sample and place it in a -50°C low temperature box for 5h. Take it out and install the bending fixture. Bend it with a radius of 6mm and apply a tensile force of 50N. Observe the cracking condition (none, slight, moderate, severe).

[0178] 3. Test results and analysis;

[0179] (1) Thermal insulation performance test results

[0180]

[0181] Analysis: The thermal conductivity of the embodiment is lower than that of the comparative example, because the inner layer material is matched, and the embodiment 3 is the lowest;

[0182] (2) Low temperature impact performance test results

[0183]

[0184] Analysis: Under low temperature impact, the energy of the embodiment is higher than that of the comparative example, and the embodiment 3 is outstanding;

[0185] (3) Cracking resistance test results

[0186]

[0187] Analysis: The crack resistance of the embodiment is better than that of the comparative example, and the embodiment 3 is the best;

[0188] 4. Conclusion

[0189] The following conclusions can be drawn from the thermal insulation performance, low temperature impact performance and crack resistance tests of the low temperature resistant thermal insulation composite material embodiment 2, embodiment 3, embodiment 4 and comparative example 1 and comparative example 2 of the present invention:

[0190] (1) The application of low-temperature resistant and anti-cracking additives significantly improves the thermal insulation performance, low-temperature impact performance and crack resistance of the composite material of the present invention;

[0191] (2) The application of ethylene-vinyl acetate copolymer can improve the flexibility and impact resistance of composite materials.

[0192] Obviously, the described embodiments are only some embodiments of the present invention, not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field and related fields without creative work should fall within the scope of protection of the present invention. The structures, devices and operating methods not specifically described and explained in the present invention are implemented according to the conventional means in the field unless otherwise specified and limited.

Claims

1. A low temperature resistant heat insulating composite material, characterized in that: It includes an outer protective layer, an intermediate reinforcement layer and an inner thermal insulation layer; Wherein, the inner insulation layer comprises the following components by weight: 3-5 parts by mass of aerogel, 70-80 parts by mass of polytetrafluoroethylene powder, 8-10 parts by mass of hollow glass microspheres, 9-11 parts by mass of azodicarbonamide and 7-8 parts by mass of nano talc; The intermediate reinforcement layer comprises the following weight components: 11-13 parts by mass of ethylene-propylene rubber, 6-7 parts by mass of polyphenylene ester, 30-35 parts by mass of aluminum hydroxide, 3-4 parts by mass of antimony trioxide and 15-18 parts by mass of chlorinated paraffin; The outer protective layer comprises the following components by weight: 85-90 parts by mass of PVC resin, 7-9 parts by mass of wear-resistant filler, 18-22 parts by mass of modified filler, 25-26 parts by mass of ethylene-vinyl acetate copolymer, 4-8 parts by mass of composite heat stabilizer, 2.5-4 parts by mass of dispersant, 1.3-2.2 parts by mass of lubricant, 4.5-5.5 parts by mass of mixed silane coupling agent, 2-4 parts by mass of plasticizer, 2.3-3.6 parts by mass of antioxidant, 4.5-4.8 parts by mass of compatibilizer and 12-15 parts by mass of low temperature resistant anti-cracking additive; The low temperature resistant anti-cracking 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 silicon dioxide, 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; The specific preparation method of the low temperature resistant anti-cracking additive is as follows: Step 1: Add polyimide resin, polyetheretherketone resin and silicone rubber into a reaction kettle, heat and mix at high speed, the heating time is 50 minutes, the heating temperature is 85° C., add nano-silicon dioxide and glass fiber into the reaction kettle, and mix to obtain matrix A; Step 2: Add polydimethylsiloxane to matrix A, heat and mix, start ultrasonic dispersion, and then stir and mix; Step 3: adding an antioxidant and an ultraviolet absorber into a reaction kettle, heating and stirring to obtain a low-temperature resistant anti-cracking additive.

2. The low temperature resistant heat insulating composite material according to claim 1, characterized in that: The specific preparation method of the modified filler is as follows: A1. Pour toluene into a reaction kettle and heat it to 80-82° C. The amount of toluene is 120 parts by mass. Dissolve the initiator dibenzoyl peroxide in toluene. The amount of the initiator dibenzoyl peroxide is 10 parts by mass. A2, methyl methacrylate, butyl acrylate, styrene, a crosslinking agent and a functional monomer hydroxyethyl methacrylate are uniformly mixed, wherein divinylbenzene is used as the crosslinking agent, and after mixing, the mixture is added dropwise to a reaction kettle, and the temperature is maintained at 80 degrees Celsius for reaction, wherein the weight ratio of the methyl methacrylate, butyl acrylate, styrene, a crosslinking agent and a functional monomer hydroxyethyl methacrylate is 40:30:20:1:1:3; A3. After the reaction is completed, cool to room temperature, pour the product into methanol for precipitation, filter and dry. The amount of methanol used is 3 times that of the reaction system to obtain polymer filler B; A4, drying nano calcium carbonate and nano titanium dioxide, wherein the mass ratio of polymer filler B: nano calcium carbonate and nano titanium dioxide is 1:1, adding the dried nano calcium carbonate and nano titanium dioxide into a high-speed mixer, adding silane coupling agent KH-550, stearic acid and polyethylene glycol 4000, mixing and stirring, then adding polymer filler B, continuing to mix and stir, and the surface of the filler is fully covered by the treatment agent silane coupling agent KH-550, stearic acid and polyethylene glycol 4000 and polymer filler B, and the mixing is completed; A5. After the mixing is completed, the surface treated material is taken out from the high-speed mixer and cooled to room temperature to obtain a modified filler.

3. The low temperature resistant heat insulating composite material according to claim 2, characterized in that: 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 put them into a high-pressure reactor with a stirring device. The pressure of the reactor is controlled at 150-250 MPa and the temperature is controlled at 200-250°C. C2. Add 10 parts by mass of dibenzoyl peroxide as an initiator into a reactor, and carry out polymerization reaction for 5-10 hours. After the reaction, cool the reaction solution to room temperature, and then pour the polymer solution into methanol to precipitate. After filtering, washing and drying, ethylene-vinyl acetate copolymer is obtained.

4. A method for preparing a low-temperature resistant thermal insulation composite material, characterized in that: The method comprises the following preparation steps: S1, preparation of inner thermal insulation layer, adding 3-5 parts by mass of aerogel, 70-80 parts by mass of polytetrafluoroethylene powder, 8-10 parts by mass of hollow glass microspheres, 9-11 parts by mass of azodicarbonamide and 7-8 parts by mass of nano talc into a high-speed mixer, mixing evenly, and then hot pressing to obtain the inner thermal insulation layer at a pressure of 5-10 MPa and a temperature of 150-200° C. for 1-2 hours; S2, preparation of the intermediate reinforcement layer, adding 11-13 parts by mass of ethylene propylene rubber, 6-7 parts by mass of polyphenylene ester, 30-35 parts by mass of aluminum hydroxide, 3-4 parts by mass of antimony trioxide, and 15-18 parts by mass of chlorinated paraffin material into an internal mixer for mixing, the mixing temperature is 120-200° C., the mixing time is 2 hours, the mixed material is extruded by an extruder, and the intermediate reinforcement layer is obtained after cooling to room temperature; S3, outer protective layer preparation, 85-90 parts by mass of PVC resin, 7-9 parts by mass of wear-resistant filler, 18-22 parts by mass of modified filler, 25-26 parts by mass of ethylene-vinyl acetate copolymer, 4-8 parts by mass of composite heat stabilizer, 2.5-4 parts by mass of dispersant, 1.3-2.2 parts by mass of lubricant, 4.5-5.5 parts by mass of mixed silane coupling agent, 2-4 parts by mass of plasticizer, 2.3-3.6 parts by mass of antioxidant, 4.5-4.8 parts by mass of compatibilizer and 12-15 parts by mass of low temperature resistant anti-cracking additive are added to a high-speed mixer, the mixing time is 1 hour, and the mixed materials are extruded by an extruder to obtain an outer protective layer; The compatibilizer is any one of maleic anhydride grafted ethylene-vinyl acetate copolymer and acrylate-maleic anhydride copolymer; S4. Stack the inner insulation layer, the middle reinforcement layer and the outer protection layer in sequence, put them into a hot press, control the pressure at 10-15MPa, and control the temperature at 180-220°C for hot pressing and compounding for 30 minutes to obtain a low-temperature resistant thermal insulation composite material.

5. The method for preparing a low-temperature resistant heat-insulating composite material according to claim 4, characterized in that: The internal mixer control system in step S2 is composed 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; Wherein, the temperature control module includes a temperature sensor, a heating device and a cooling device, and the temperature sensor is installed on the wall of the mixing chamber to monitor the temperature in real time and convert the signal; The speed control module is composed of a controller and a servo motor, and the controller adjusts the speed of the servo motor according to a preset process and an operation instruction; The time control module includes a timer, which performs timing control on mixing 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 monitor the feeding amount through a sensor.

6. The method for preparing a low-temperature resistant heat-insulating composite material according to claim 5, characterized in that: The temperature control module adopts a PID control algorithm to adjust the output power of the heating device and the cooling device based on the deviation between the temperature feedback from the temperature sensor and the preset temperature setting value.

7. The method for preparing a low-temperature resistant heat-insulating composite material according to claim 6, characterized in that: The operating steps of the internal mixer are specifically as follows: D1. Start the internal mixer control system and input process parameters, stage speed requirements, mixing time and feeding data; D2. First, the temperature control module starts the heating device for preheating, and 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 and adds the materials into the mixing chamber; D4. After the addition is completed, the internal mixer enters the mixing stage to mix the materials; D5. After the internal mixing is completed, open the discharge valve of the internal mixer to discharge the mixed rubber material.

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