TPU (Thermoplastic Polyurethane) film containing carbon nanotubes for warm-keeping products and preparation method of TPU film
By processing and modifying the carbon nanotubes, they are evenly dispersed in the TPU film and formed a thermal conductivity network. Combined with the preparation of porous TPUs, the problem of poor warming effect of traditional warming materials is solved, and more efficient warming effect and TPU film performance are achieved.
Patent Information
- Application Number
- CN202510363203.5
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-03-26
- Publication Date
- 2025-06-27
- Estimated Expiration
- Not applicable · inactive patent
AI Technical Summary
Traditional warm-keeping materials have limited warming effects in actual applications, heavy materials and insufficient comfort. Uneven dispersion of carbon nanotubes in the material leads to uneven performance.
Through the treatment liquid, deposition treatment and modification treatment, the dispersion, binding force, compatibility and stability of the carbon nanotubes are improved, so that they are dispersed more uniformly in the TPU film, forming a continuous thermal conductivity network, and a porous TPU is prepared using sodium bicarbonate to improve the contact area and binding force of the material.
The uniform dispersion and efficient thermal conductivity of carbon nanotubes in the TPU film are achieved, and the warmth preservation effect and the overall performance of the TPU film are improved.
Smart Images
Figure BDA0005329233120000101
Abstract
Description
Technical Field
[0001] The present invention belongs to the technical field of TPU materials, and relates to a TPU film containing carbon nanotubes for thermal insulation products and a preparation method thereof. Background Art
[0002] In today's society, people's activity scenarios are becoming increasingly diverse. Whether it is various sports and work in the cold outdoors or the pursuit of a comfortable temperature environment indoors, higher requirements are put forward for thermal insulation products. However, traditional thermal insulation materials still have many limitations in actual applications. For example, the thermal insulation effect is limited, and it can only block cold air to a certain extent, or the material is too thick and heavy, and the comfort is not enough. Carbon nanotubes have high heat transfer characteristics, and the materials are flexible, light, and thin enough, and have high hardness. However, carbon nanotubes have an extremely high aspect ratio, and their slender shape enables them to generate a large interaction area when in contact, thereby generating strong van der Waals forces, making them extremely easy to attract and aggregate together in the natural state. The aggregated carbon nanotubes are difficult to disperse evenly in other materials, and the binding force with other materials is extremely poor, resulting in uneven material performance, and there may be defects or weak points locally. Summary of the Invention
[0003] The purpose of the present invention is to provide a TPU film containing carbon nanotubes for thermal insulation products and a preparation method thereof. Through treatment liquid, deposition treatment, and modification treatment, the dispersion, binding force, compatibility, and stability of carbon nanotubes are improved, so that the treated carbon nanotubes are more evenly dispersed in the TPU film, forming a continuous heat conduction network. On this basis, porous TPU is prepared with sodium bicarbonate. The pores reduce the material density and heat capacity, while increasing the contact area and binding force between various materials, synergistically improving the thermal insulation effect and enhancing the performance of the TPU film.
[0004] The purpose of the present invention can be achieved by the following technical solutions:
[0005] A preparation method of a TPU film containing carbon nanotubes for thermal insulation products, the preparation method of the TPU film containing carbon nanotubes comprises the following steps:
[0006] (1) Add the treated carbon nanotubes to porous TPU according to a mass ratio of 1.2 - 3.6:5.7 - 8.2, mix in a high-speed mixer and then melt and extrude to obtain a mixture;
[0007] (2) Coat the mixture on a release paper through a coater, cool and solidify to obtain an inner film;
[0008] (3) Mix the porous TPU, flame retardant, and insulating agent in a mass ratio of 7 - 11:2.1 - 3:0.05 - 0.15, then perform mixing and melt extrusion in a high-speed mixer, cast it onto the inner film, dry it, and cure it to obtain a TPU film containing carbon nanotubes.
[0009] Furthermore, the treatment method of the carbon nanotubes after the treatment in step (1) includes the following steps:
[0010] X1. Immerse the carbon nanotubes in the treatment liquid at a volume ratio of 1:2.5 - 4.5, take them out after ultrasonic treatment, and drain to obtain a drained product;
[0011] X2. Disperse the drained product in 8 - 12 times the weight of absolute ethanol, and simultaneously drip the precipitation liquid. Set the stirring speed to 100 - 200 rmp, the stirring temperature to 30 - 40 °C, stir for 2 - 3 h to obtain a mixed liquid, ultrasonic for 10 - 20 min, then filter, wash the precipitate with deionized water, and dry to obtain a deposited product;
[0012] X3. Disperse the deposited product in 5 - 10 times the weight of absolute ethanol, add γ-aminopropyltriethoxysilane with a mass of 5 - 10 wt% of the deposited product, set the stirring temperature to 35 - 45 °C, the stirring speed to 250 - 350 rmp, stop dripping the precipitation liquid after stirring for 1.8 - 2.2 h, filter, wash the solid with deionized water, and vacuum dry at 60 °C for 3 - 5 h to obtain the treated carbon nanotubes.
[0013] Furthermore, the raw materials of the treatment liquid in step X1 include 41 - 69 wt% sodium dodecylbenzenesulfonate, 5.2 - 7 wt% phosphatidylethanolamine, and the balance deionized water.
[0014] Furthermore, the precipitation liquid in step X2 includes a 0.1 - 0.2 mol / L calcium nitrate solution and a 0.1 - 0.2 mol / L ammonium carbonate solution; the dropping ratio of the calcium nitrate solution to the ammonium carbonate solution in the precipitation liquid is 1:1, and the dropping speed is 1 - 3 drops / s.
[0015] Furthermore, the parameters of the ultrasonic step are all: the ultrasonic frequency is 40 - 50 kHz, and the ultrasonic power is 400 - 800 W; the filter used is a 100-mesh filter cloth.
[0016] Furthermore, the preparation method of the porous TPU in step (1) is:
[0017] Load TPU particles and sodium bicarbonate with an average particle size of 20 - 50 μm into a high - speed mixer according to a mass ratio of 1:0.05 - 0.15, stir at a speed of 1000 - 2000 rmp for 15 - 25 min, set the screw speed to 180 - 220 rmp, the extrusion temperature to 130 - 150 °C, and cool after extrusion to obtain porous TPU.
[0018] Further, the speed and time of the treatment by the high - speed mixer in step (1) are 2000 - 3000 rmp and 30 - 60 min respectively; the parameters of the extruder are: the extrusion temperature is 120 - 180 °C, and the screw speed is 50 - 100 rmp.
[0019] Further, the coating thickness in step (2) is 0.05 - 0.11 mm; the cooling temperature in the post - cooling curing is 20 - 30 °C, and the curing time is 1 - 2 h.
[0020] Further, the speed and time of the treatment by the high - speed mixer in step (3) are 1000 - 2000 rmp and 20 - 30 min respectively; the parameters of the casting step are: the casting temperature is 150 - 180 °C, the casting speed is 5 - 10 m / min, the number of casting times is 3 times, and the thickness of each casting is 0.02 - 0.04 mm; the drying temperature in the post - drying curing is 80 - 100 °C, and the curing time is 2 - 3 h.
[0021] Advantages of the present invention:
[0022] (1) The carbon nanotubes of the present invention are successively treated with a treatment liquid, deposited, and modified. Among them, sodium dodecylbenzenesulfonate in the treatment liquid can form a coating layer on the surface of the carbon nanotubes during the impregnation process, reducing their surface energy, increasing the steric hindrance between the carbon nanotubes, and effectively improving the dispersibility of the carbon nanotubes. Phosphatidylethanolamine contains polar functional groups such as phosphate groups and amide groups, which can interact with the active sites on the surface of the carbon nanotubes to further improve the binding force. At the same time, the molecular structure of phosphatidylethanolamine also has a certain flexibility, which can play a bridging role between the carbon nanotubes and other materials, improving the compatibility between the carbon nanotubes and other materials and enhancing the interfacial binding force; during the deposition treatment, calcium carbonate precipitate will gradually deposit on the surface of the carbon nanotubes, forming a relatively rough coating layer, thereby increasing the surface roughness and specific surface area of the carbon nanotubes, further increasing the contact area and interaction between the carbon nanotubes and other materials, and also improving the stability of the carbon nanotubes to prevent them from agglomerating or settling during subsequent treatment processes; finally, γ-aminopropyltriethoxysilane is used for modification treatment. The siloxane groups therein can interact with functional groups such as hydroxyl groups on the surface of the carbon nanotubes and can also interact with polar groups in the TPU, thereby establishing a connection between the carbon nanotubes and the TPU, enhancing their binding force, and preventing the carbon nanotubes from falling off or agglomerating from the TPU film during use; in addition, the treated carbon nanotubes are more uniformly dispersed in the TPU film, which helps to form a more continuous heat conduction network, fully exert their excellent heat conduction performance, and improve the heat preservation effect of the TPU film.
[0023] (2) The present invention uses sodium bicarbonate to prepare porous TPU. The relatively large number of pores reduces the density and heat capacity of the material, and the air in the pores has a low thermal conductivity, which can effectively block the transfer of heat, extend the time of heat conduction, and improve the heat preservation effect of the TPU film; at the same time, the porous structure can also provide space for the filling of other materials, helping to increase the contact area and binding force between various materials, and further improving the performance of the TPU film. Detailed implementation mode
[0024] To further elaborate on the technical means and effects adopted by the present invention to achieve the predetermined invention purpose, the following combines examples to describe in detail the specific implementation mode, structure, characteristics, and effects according to the present invention.
[0025] Example 1
[0026] A preparation method of a TPU film containing carbon nanotubes for thermal insulation products. The preparation method of the TPU film containing carbon nanotubes in this example includes the following steps:
[0027] (1) Add the treated carbon nanotubes to the porous TPU in a mass ratio of 1.2:5.7, mix in a high-speed blender and then melt-extrude to obtain a mixed material.
[0028] (2) Coat the mixed material on the release paper through a coater, cool and then cure to obtain an inner film.
[0029] (3) Mix the porous TPU, flame retardant and insulating agent in a mass ratio of 7:2.1:0.05, mix in a high-speed blender and then melt-extrude, cast it onto the inner film, dry and then cure to obtain a TPU film containing carbon nanotubes.
[0030] The flame retardant and insulating agent in this embodiment are decabromodiphenylethane and polytetrafluoroethylene respectively.
[0031] The treatment method of the treated carbon nanotubes in this embodiment in step (1) includes the following steps:
[0032] X1. Immerse the carbon nanotubes in the treatment liquid at a volume ratio of 1:2.5, take them out after ultrasonic treatment, drain to obtain a drained product.
[0033] X2. Disperse the drained product in 8 times the weight of absolute ethanol, and at the same time dropwise add the precipitation liquid. Set the stirring speed to 100 rmp, the stirring temperature to 30 °C, stir for 2 h to obtain a mixed liquid, ultrasonic for 10 min, then filter, wash the precipitate with deionized water, and dry to obtain a deposited product.
[0034] X3. Disperse the deposited product in 5 times the weight of absolute ethanol, add γ-aminopropyltriethoxysilane with a mass of 5 wt% of the deposited product, set the stirring temperature to 35 °C, the stirring speed to 250 rmp, stop dropping the precipitation liquid after stirring for 1.8 h, filter, wash the solid with deionized water, and vacuum dry at 60 °C for 3 h to obtain the treated carbon nanotubes.
[0035] The raw materials of the treatment liquid in this embodiment in step X1 include 41 wt% sodium dodecylbenzenesulfonate, 5.2 wt% phosphatidylethanolamine and the balance deionized water.
[0036] The precipitation liquid in this embodiment in step X2 includes 0.1 mol / L calcium nitrate solution and 0.1 mol / L ammonium carbonate solution; the dropping ratio of the calcium nitrate solution and ammonium carbonate solution in the precipitation liquid is 1:1, and the dropping speed is 1 drop / s.
[0037] The parameters of the ultrasonic steps in this embodiment are all: the ultrasonic frequency is 40 kHz, and the ultrasonic power is 400 W; the filter cloth used for filtration in this embodiment is all 100-mesh filter cloth.
[0038] The preparation method of the porous TPU in this embodiment in step (1) is:
[0039] Load TPU particles and sodium bicarbonate with an average particle size of 20 μm into a high-speed mixer at a mass ratio of 1:0.05, stir at a speed of 1000 rmp for 15 min, set the screw speed to 180 rmp, and the extrusion temperature to 130 °C. After extrusion, cool to obtain porous TPU.
[0040] In step (1), the speed and time of the high-speed mixer treatment in this embodiment are 2000 rmp and 30 min respectively; the parameters of the extruder are: the extrusion temperature is 120 °C, and the screw speed is 50 rmp.
[0041] In step (2), the coating thickness in this embodiment is 0.05 mm; the cooling temperature during post-cooling curing is 20 °C, and the curing time is 1 h.
[0042] In step (3), the speed and time of the high-speed mixer treatment in this embodiment are 1000 rmp and 20 min respectively; the parameters of the casting step are: the casting temperature is 150 °C, the casting speed is 5 m / min, the number of casting times is 3 times, and the thickness of each casting is 0.02 mm; the drying temperature during post-drying curing is 80 °C, and the curing time is 2 h.
[0043] Example 2
[0044] A method for preparing a TPU film containing carbon nanotubes for thermal insulation products. The method for preparing the TPU film containing carbon nanotubes in this embodiment includes the following steps:
[0045] (1) Add the treated carbon nanotubes to the porous TPU at a mass ratio of 3.6:8.2, mix in a high-speed mixer and then melt and extrude to obtain a mixture.
[0046] (2) Coat the mixture on a release paper through a coater, cool and then cure to obtain an inner film.
[0047] (3) Mix porous TPU, a flame retardant and an insulating agent at a mass ratio of 11:3:0.15, mix in a high-speed mixer and then melt and extrude, cast onto the inner film, dry and then cure to obtain a TPU film containing carbon nanotubes.
[0048] The flame retardant and insulating agent in this embodiment are 1,2-bis(2,6-dibromophenyl)ethane and polytetrafluoroethylene respectively.
[0049] In step (1), the treatment method of the treated carbon nanotubes in this embodiment includes the following steps:
[0050] X1. Immerse the carbon nanotubes in the treatment liquid at a volume ratio of 1:4.5, take them out after ultrasonic treatment, and drain to obtain a drained product.
[0051] X2. Disperse the drained product in 12 times its weight of absolute ethanol, and simultaneously add the precipitation solution dropwise. Set the stirring speed to 200 rmp, the stirring temperature to 40 °C, stir for 3 h to obtain a mixed solution, sonicate for 20 min, then filter, wash the precipitate with deionized water, and dry to obtain the deposited product;
[0052] X3. Disperse the deposited product in 10 times its weight of absolute ethanol, add γ-aminopropyltriethoxysilane with a mass of 10 wt% of the deposited product, set the stirring temperature to 45 °C, the stirring speed to 350 rmp, stop adding the precipitation solution after stirring for 2.2 h, filter, wash the solid with deionized water, and vacuum dry at 60 °C for 5 h to obtain the treated carbon nanotubes.
[0053] In step X1, the raw materials of the treatment liquid in this embodiment include 69 wt% sodium dodecylbenzenesulfonate, 7 wt% phosphatidylethanolamine, and the balance deionized water.
[0054] In step X2, the precipitation solution in this embodiment includes a 0.2 mol / L calcium nitrate solution and a 0.2 mol / L ammonium carbonate solution; the dropping ratio of the calcium nitrate solution to the ammonium carbonate solution in the precipitation solution is 1:1, and the dropping speed is 3 drops / s.
[0055] The parameters of the sonication step in this embodiment are: the sonication frequency is 50 kHz, and the sonication power is 800 W; a 100-mesh filter cloth is used for filtration in this embodiment.
[0056] In step (1), the preparation method of the porous TPU in this embodiment is as follows:
[0057] Load TPU particles and sodium bicarbonate with an average particle size of 50 μm into a high-speed mixer at a mass ratio of 1:0.15, stir at a speed of 2000 rmp for 25 min, set the screw speed to 220 rmp, the extrusion temperature to 150 °C, and cool after extrusion to obtain porous TPU.
[0058] In step (1), the rotation speed and time of the high-speed mixer treatment in this embodiment are 3000 rmp and 60 min respectively; the parameters of the extruder are: the extrusion temperature is 180 °C, and the screw speed is 100 rmp.
[0059] In step (2), the coating thickness in this embodiment is 0.11 mm; the cooling temperature during post-cooling curing is 30 °C, and the curing time is 2 h.
[0060] In step (3), the rotation speed and time of the high-speed mixer treatment in this embodiment are 2000 rmp and 30 min respectively; the parameters of the casting step are: the casting temperature is 180 °C, the casting speed is 10 m / min, the number of casting times is 3 times, and the thickness of each casting is 0.04 mm; the drying temperature during post-drying curing is 100 °C, and the curing time is 3 h.
[0061] Example 3
[0062] A preparation method of a TPU film containing carbon nanotubes for thermal insulation products. The preparation method of the TPU film containing carbon nanotubes in this example comprises the following steps:
[0063] (1) Add the treated carbon nanotubes to porous TPU according to a mass ratio of 2.4:6.95, mix in a high-speed mixer and then melt and extrude to obtain a mixture;
[0064] (2) Coat the mixture on a release paper through a coater, cool and then cure to obtain an inner film;
[0065] (3) Mix porous TPU, a flame retardant and an insulating agent according to a mass ratio of 9:2.55:0.10, mix in a high-speed mixer and then melt and extrude, cast onto the inner film, dry and then cure to obtain a TPU film containing carbon nanotubes.
[0066] The flame retardant and the insulating agent in this example are decabromodiphenylethane and polytetrafluoroethylene respectively.
[0067] The treatment method of the treated carbon nanotubes in step (1) in this example comprises the following steps:
[0068] X1. Immerse the carbon nanotubes in a treatment liquid according to a volume ratio of 1:3.5, take them out after ultrasonic treatment, drain to obtain a drained product;
[0069] X2. Disperse the drained product in 10 times the weight of absolute ethanol, and at the same time dropwise add a precipitation liquid. Set the stirring speed to 150 rmp, the stirring temperature to 35 °C, stir for 2.5 h to obtain a mixed liquid, ultrasonic for 15 min, then filter, wash the precipitate with deionized water, and dry to obtain a deposited product;
[0070] X3. Disperse the deposited product in 7.5 times the weight of absolute ethanol, add γ-aminopropyltriethoxysilane accounting for 7.5 wt% of the mass of the deposited product, set the stirring temperature to 40 °C, the stirring speed to 300 rmp, stop dropping the precipitation liquid after stirring for 2 h, filter, wash the solid with deionized water, and vacuum dry at 60 °C for 4 h to obtain the treated carbon nanotubes.
[0071] The raw materials of the treatment liquid in step X1 in this example include 55 wt% sodium dodecylbenzenesulfonate, 6.1 wt% phosphatidylethanolamine and the balance deionized water.
[0072] The precipitation liquid in step X2 in this example includes a 0.15 mol / L calcium nitrate solution and a 0.15 mol / L ammonium carbonate solution; the dropping ratio of the calcium nitrate solution and the ammonium carbonate solution in the precipitation liquid is 1:1, and the dropping speed is 2 drops / s.
[0073] The parameters of the ultrasonic step in this embodiment are as follows: the ultrasonic frequency is 45 kHz, and the ultrasonic power is 600 W; 100-mesh filter cloth is used for filtration in this embodiment.
[0074] In step (1), the preparation method of the porous TPU in this embodiment is as follows:
[0075] Load TPU particles and sodium bicarbonate with an average particle size of 35 μm into a high-speed mixer according to a mass ratio of 1:0.10, stir at a speed of 1500 rmp for 20 min, set the screw speed to 200 rmp, and the extrusion temperature to 140 °C. After extrusion, cool to obtain porous TPU.
[0076] In step (1), the rotation speed and time of the high-speed mixer treatment in this embodiment are 2500 rmp and 45 min respectively; the parameters of the extruder are: the extrusion temperature is 160 °C, and the screw speed is 75 rmp.
[0077] In step (2), the coating thickness in this embodiment is 0.08 mm; the cooling temperature during post-cooling curing is 25 °C, and the curing time is 1.5 h.
[0078] In step (3), the rotation speed and time of the high-speed mixer treatment in this embodiment are 1500 rmp and 25 min respectively; the parameters of the casting step are: the casting temperature is 165 °C, the casting speed is 7.5 m / min, the number of casting times is 3 times, and the thickness of each casting is 0.03 mm; the drying temperature during post-drying curing is 90 °C, and the curing time is 2.5 h.
[0079] Comparative Example 1
[0080] On the basis of Example 3, remove the treatment with the treatment liquid in step X1, and keep other conditions the same as in Example 3.
[0081] Comparative Example 2
[0082] On the basis of Example 3, remove phosphatidylethanolamine from the treatment liquid and replace it with deionized water of equal weight, and keep other conditions the same as in Example 3.
[0083] Comparative Example 3
[0084] On the basis of Example 3, remove the deposition treatment in step X2, and keep other conditions the same as in Example 3.
[0085] Comparative Example 4
[0086] On the basis of Example 3, remove the modification treatment in step X3, and keep other conditions the same as in Example 3.
[0087] Comparative Example 5
[0088] Based on Example 3, the TPU is not subjected to porous treatment. Other conditions are the same as those in Example 3.
[0089] Taking the TPU films prepared in Examples 1 - 3 and Comparative Examples 1 - 5 as samples, the peel strength (N / 15mm) was detected according to the 4004 Plastic Peel Strength Measurement Method; at the same time, the samples were placed in a basin, the water temperature was 40 °C, washing powder was added, and they were rubbed 40 times at a rate of 10 min / time to observe whether the samples showed cracking or peeling; the results are recorded in Table 1 below.
[0090] Table 1
[0091]
[0092] As can be seen from Table 1, the carbon nanotubes in the TPU films containing carbon nanotubes prepared in Examples 1 - 3 of the present invention are evenly dispersed and there is a good bonding force between the various materials, making them not easy to peel, and no cracking or peeling occurred after multiple rubbings. In Comparative Examples 1 - 4, a certain treatment step of the carbon nanotubes was changed respectively. The carbon nanotubes of the present invention were successively treated with a treatment liquid, deposited, and modified. Through specific components and processes, the dispersion ability of the carbon nanotubes in the TPU and the bonding ability with the TPU were improved step by step, and any change could not achieve the effects presented by the present invention; in Comparative Example 5, the porous TPU was also replaced with TPU. The porous structure can provide space for the filling of other materials, which helps to increase the contact area and bonding force between the various materials, so the effect becomes worse after the change.
[0093] The above are only the preferred embodiments of the present invention and do not impose any form of limitation on the present invention. Although the present invention has been disclosed above with the preferred embodiments, it is not intended to limit the present invention. Any person skilled in the art can make some changes or modifications to the above - disclosed technical content to obtain equivalent embodiments with equivalent changes, but as long as the technical content of the present invention is not departed from, any indirect modification, equivalent change, and modification made to the above embodiments based on the technical essence of the present invention still fall within the scope of the technical solution of the present invention.
Claims
1. A method for preparing a TPU film containing carbon nanotubes for thermal insulation products, characterized in that: The method for preparing the TPU film containing carbon nanotubes comprises the following steps: (1) adding the treated carbon nanotubes to the porous TPU in a mass ratio of 1.2-3.6:5.7-8.2, mixing in a high-speed mixer and then melt-extruding to obtain a mixture; (2) coating the mixture on a release paper through a coating machine, and solidifying it after cooling to obtain a lining film; (3) The porous TPU, flame retardant and insulating agent are mixed in a mass ratio of 7-11:2.1-3:0.05-0.15, mixed in a high-speed mixer, melt-extruded, cast onto an inner film, dried and solidified to obtain a TPU film containing carbon nanotubes.
2. The method for preparing a TPU film containing carbon nanotubes for thermal insulation products according to claim 1, characterized in that: The method for treating the treated carbon nanotubes in step (1) comprises the following steps: X1. Immersing the carbon nanotubes in a treatment solution at a volume ratio of 1:2.5-4.5, taking them out after ultrasonic treatment, and draining them to obtain a drained product; X2. The drained product was dispersed in 8-12 times the weight of anhydrous ethanol, and the precipitate was added dropwise, the stirring speed was set to 100-200rmp, the stirring temperature was 30-40°C, and the mixture was stirred for 2-3h, ultrasonicated for 10-20min, and then filtered, the precipitate was rinsed with deionized water, and dried to obtain a deposited product; X3. The deposited product is dispersed in 5-10 times the weight of anhydrous ethanol, and 5-10wt% of the mass of the deposited product is added with γ-aminopropyltriethoxysilane. The stirring temperature is set to 35-45°C and the stirring speed is set to 250-350rmp. After stirring for 1.8-2.2h, stop adding the precipitate, filter, rinse the solid with deionized water, and vacuum dry at 60°C for 3-5h to obtain the treated carbon nanotubes.
3. The method for preparing a TPU film containing carbon nanotubes for thermal insulation products according to claim 2, characterized in that: The raw materials of the treatment liquid in step X1 include 41-69wt% sodium dodecylbenzene sulfonate, 5.2-7wt% phosphatidylethanolamine and the balance deionized water.
4. The method for preparing a TPU film containing carbon nanotubes for thermal insulation products according to claim 2, characterized in that: The precipitating solution in step X2 comprises 0.1-0.2 mol / L calcium nitrate solution and 0.1-0.2 mol / L ammonium carbonate solution; the dropping ratio of the calcium nitrate solution and the ammonium carbonate solution in the precipitating solution is 1:1, and the dropping speed is 1-3 drops / s.
5. The method for preparing a TPU film containing carbon nanotubes for thermal insulation products according to claim 2, characterized in that: The parameters of the ultrasonic step are: ultrasonic frequency is 40-50kHz, ultrasonic power is 400-800W; and the filter cloth used for filtration is 100 mesh.
6. The method for preparing a TPU film containing carbon nanotubes for thermal insulation products according to claim 1, characterized in that: The preparation method of the porous TPU in step (1) is: The TPU particles and sodium bicarbonate with an average particle size of 20-50 μm are charged into a high-speed mixer at a mass ratio of 1:0.05-0.15, stirred at a speed of 1000-2000 rpm for 15-25 min, the screw speed is set to 180-220 rpm, the extrusion temperature is 130-150° C., and cooled after extrusion to obtain porous TPU.
7. The method for preparing a TPU film containing carbon nanotubes for thermal insulation products according to claim 1, characterized in that: The speed and time of the high-speed mixer in step (1) are 2000-3000 rpm and 30-60 min respectively; the parameters of the extruder are: extrusion temperature is 120-180° C., and screw speed is 50-100 rpm.
8. The method for preparing a TPU film containing carbon nanotubes for thermal insulation products according to claim 1, characterized in that: The coating thickness in step (2) is 0.05-0.11 mm; the cooling temperature in the post-cooling solidification is 20-30° C., and the solidification time is 1-2 h.
9. The method for preparing a TPU film containing carbon nanotubes for thermal insulation products according to claim 1, characterized in that: The speed and time of the high-speed stirrer in step (3) are 1000-2000 rpm and 20-30 min respectively; the parameters of the casting step are: the casting temperature is 150-180° C., the casting speed is 5-10 m / min, the number of castings is 3 times, and the thickness of each casting is 0.02-0.04 mm; the drying temperature in the post-drying curing is 80-100° C., and the curing time is 2-3 h.