Polyimide-based composite heat insulation film laminated material structure and preparation method thereof

Abstract

The invention relates to a polyimide-based composite heat-insulating film laminated material structure and a preparation method thereof, the polyimide-based composite heat-insulating film laminated material structure comprises a polyimide heat-insulating base film and a polyimide heat-insulating fiber film which are cross-linked and bonded, and a metal reflecting layer is deposited on one side, back to the polyimide heat-insulating fiber film, of the polyimide heat-insulating base film. Although the polyimide heat insulation fiber membrane has a good heat insulation effect, the polyimide heat insulation fiber membrane is poor in mechanical property and has a large number of pores, and the polyimide heat insulation base membrane is designed in the laminated structure and serves as a mechanical supporting layer and an airtight layer of the laminated structure; the problems of poor mechanical property and poor heat convection protection of a polyimide heat insulation fiber membrane can be effectively solved, the polyimide heat insulation fiber membrane with a rich pore structure is designed in a laminated structure, the heat conductivity of the laminated material of the composite film can be greatly reduced, and in addition, by designing a metal reflecting layer in the laminated structure, the heat conductivity of the laminated material of the composite film can be greatly improved. And a good radiation heat protection effect can be achieved.

Description

Technical Field

[0001] The invention relates to the technical field of polyimide composite film preparation, and in particular to a polyimide-based composite thermal insulation film laminate material structure and a preparation method thereof. Background Art

[0002] Polyimide (PI) refers to a class of polymers containing imide rings in the main chain. Due to the presence of highly rigid structure and strong intermolecular association force in the molecular chain, it has excellent thermal stability, mechanical properties, dielectric properties, chemical stability, etc. It is widely used in aerospace, microelectronics, optoelectronic engineering, high-temperature insulation materials, gas separation and other fields.

[0003] Traditional thermal insulation materials have limited application scope due to their own defects, while polyimide has excellent comprehensive performance. When used as a thermal insulation material, it can break through the application limitations of traditional thermal insulation materials with its own performance and synthetic advantages. At present, polyimide-based thermal insulation materials mainly include polyimide foam, polyimide fiber, polyimide aerogel and polyimide-based thermal insulation composite materials. Polyimide-based composite diaphragm film materials used in small spaces have broad application prospects. The intrinsic thermal conductivity of polyimide film is about 0.2-0.3W·m -1 ·K -1 It is difficult to use it directly as a heat dissipation material. Adding thermal insulation materials such as nano-scale silica aerogel into the polyimide matrix is ​​a common composite method, but its thermal conductivity is generally 0.1W·m -1 ·K -1 The thermal insulation performance is not outstanding. Although the polyimide fiber membrane layer has a good thermal insulation effect, its mechanical properties are poor and there are a large number of pores, which is not conducive to thermal convection protection. In summary, it is urgent to propose a polyimide-based composite thermal insulation film laminate material structure and its preparation method. Summary of the invention

[0004] The technical problem to be solved by the present invention is to provide a polyimide-based composite thermal insulation film laminate material structure and a preparation method thereof in view of the deficiencies of the above-mentioned prior art.

[0005] The present invention provides a polyimide-based composite thermal insulation film laminate material structure, comprising a cross-linked and bonded polyimide thermal insulation base film and a polyimide thermal insulation fiber film, wherein a metal reflective layer is deposited on the side of the polyimide thermal insulation base film facing away from the polyimide thermal insulation fiber film; wherein the polyimide thermal insulation base film comprises a polyimide base film and a first thermal insulation filler dispersed in the polyimide base film, and the polyimide thermal insulation fiber membrane comprises a polyimide fiber membrane formed by electrospinning and a second thermal insulation filler embedded in the polyimide fiber membrane.

[0006] Preferably, the first thermal insulation filler and the second thermal insulation filler independently include any one or a combination of silica aerogel and white carbon black; the average particle size of the first thermal insulation filler and the second thermal insulation filler is independently 5-100nm; the thickness of the polyimide thermal insulation base film is 15-120μm; the thickness of the polyimide thermal insulation fiber film is 50-200μm; the thickness of the metal reflective layer is 0.5-2μm.

[0007] Preferably, the polyimide fiber filaments in the polyimide fiber membrane have a plurality of holes in an open or closed state; the specific surface area of ​​the polyimide fiber membrane is greater than or equal to 500 m 2 / g; the average diameter of the polyimide fiber filaments in the polyimide fiber membrane is 50-900nm.

[0008] The present invention also provides a method for preparing a polyimide-based composite thermal insulation film laminate material structure, comprising: performing surface treatment on a first thermal insulation filler using a first coupling agent, mixing the first thermal insulation filler with a first polyamic acid adhesive solution, coating the composite film and drying the composite film; performing surface treatment on a second thermal insulation filler using a second coupling agent, mixing the composite film with a pore-forming agent and a second polyamic acid adhesive solution, electrospinning the composite film and drying the composite film to obtain a nanofiber membrane; performing stacking and imidization between the composite film and the nanofiber membrane using a crosslinking agent solution to obtain a polyimide composite film; and depositing a metal reflective layer on the side of the polyimide composite film facing away from the nanofiber membrane to obtain a polyimide-based composite thermal insulation film.

[0009] Preferably, the first coupling agent and the second coupling agent are independently at least one of a phthalate coupling agent and an amino-functional silane coupling agent, wherein the phthalate coupling agent is at least one of PN-130, PN-101, and PN-102; and the amino-functional silane coupling agent is at least one of KH-540, KH-550, KH-560, KH-570, and KH-602.

[0010] Preferably, a first polyamic acid glue solution and a second polyamic acid glue solution are prepared independently of each other by solution polycondensation in a polar aprotic solvent using dibasic acid anhydride and diamine monomers as raw materials; the dibasic acid anhydride is any one or a combination of pyromellitic acid anhydride, 3,3',4,4'-dibenzophenone tetracarboxylic acid anhydride, 4,4'-oxydiphthalic anhydride, 3,3,4,4-diphenylsulfone tetracarboxylic acid anhydride, 3,3',4,4'-biphenyltetracarboxylic acid anhydride, and 2,3,3',4'-biphenyltetracarboxylic acid anhydride; the diamine is 4,4'-diaminodiphenyl ether, p-phenylenediamine, 4 ,4-diaminobiphenyl, 3,4'-diaminodiphenyl ether, m-phenylenediamine, 4,4'-diaminodiphenyl sulfone, 1,4-bis(4-aminophenoxy)benzene, 1,3-bis(3-aminophenoxy)benzene, any one or a combination thereof; the molar ratio of the dibasic acid anhydride to the diamine is (1-1.01):1; the polar aprotic solvent is any one or a combination of N,N-dimethylacetamide, N,N-dimethylformamide, N-methylpyrrolidone, and dimethyl sulfoxide; the solid contents of the first polyamic acid glue and the second polyamic acid glue are independently 5-25%.

[0011] Preferably, the amount of the first coupling agent is 0.5-2% of the mass of the first thermal insulation filler; the amount of the second coupling agent is 0.5-2% of the mass of the second thermal insulation filler.

[0012] Preferably, the crosslinking agent is any one of trimesoyl chloride, triisocyanate, polymaleic anhydride, 1,3,5-tris(4-aminophenoxy)benzene, melamine, or a combination thereof, and the amount of the crosslinking agent is 10-50 μL / cm 2 .

[0013] Preferably, the metal reflective layer is any one of aluminum, copper, silver and gold, and the metal reflective layer is prepared by any one of vacuum evaporation and vacuum sputtering.

[0014] Compared with the prior art, the present invention has the following beneficial effects:

[0015] 1. Although polyimide thermal insulation fiber membrane has good thermal insulation effect, its mechanical properties are poor and there are a lot of pores. Designing the polyimide thermal insulation base membrane in the laminated structure so that it serves as the mechanical support layer and airtight layer of the laminated structure can effectively solve the problems of poor mechanical properties and poor thermal convection protection of polyimide thermal insulation fiber membrane;

[0016] The thermal conductivity of polyimide insulation base film is generally 0.1W·m -1 ·K -1 The thermal insulation performance is not outstanding. The polyimide thermal insulation fiber membrane with rich pore structure is designed in the laminated structure, which can greatly reduce the thermal conductivity of the composite film laminated material;

[0017] 2. By designing a metal reflective layer in the laminated structure, it can provide good radiation heat protection;

[0018] 3. The application of cross-linking agent at the interface between polyimide thermal insulation base film and polyimide thermal insulation fiber film makes the linear polyimide molecular chain transform into a three-dimensional cross-linked network structure during interface penetration, further strengthening the interface bonding strength. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Figure 1 It is a schematic diagram of the structure of the polyimide-based composite thermal insulation film laminate material of the present invention.

[0020] Figure 2 This is a schematic diagram of the structure of polyimide composite nanofiber filaments in the polyimide thermal insulation fiber membrane of the polyimide-based composite thermal insulation film laminate material of the present invention.

[0021] Figure 3 This is the stress-strain curve of the polyimide-based composite thermal insulation film laminate material of Example 1 of the present invention.

[0022] Figure 4 This is an infrared thermal imaging image of the polyimide-based composite thermal insulation film laminate material of Example 1 of the present invention.

[0023] Illustration Description:

[0024] 100, polyimide thermal insulation base film; 200, polyimide thermal insulation fiber film; 300, metal reflective layer;

[0025] 101, polyimide matrix; 102, first thermal insulation filler; 201, polyimide fiber membrane; 202, second thermal insulation filler; 203, holes. DETAILED DESCRIPTION

[0026] In order to make the purpose, technical solution and advantages of the embodiments of the present invention clearer, the technical solution in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0027] It should be noted that when an element is referred to as being "fixed to" another element, it may be directly on the other element or there may be an intermediate element. When an element is considered to be "connected to" another element, it may be directly connected to the other element or there may be an intermediate element at the same time.

[0028] The present invention provides a polyimide-based composite thermal insulation film laminate material structure, comprising a cross-linked and bonded polyimide thermal insulation base film and a polyimide thermal insulation fiber film, wherein a metal reflective layer is deposited on the side of the polyimide thermal insulation base film facing away from the polyimide thermal insulation fiber film; wherein the polyimide thermal insulation base film comprises a polyimide base film and a first thermal insulation filler dispersed in the polyimide base film, and the polyimide thermal insulation fiber membrane comprises a polyimide fiber membrane formed by electrospinning and a second thermal insulation filler embedded in the polyimide fiber membrane.

[0029] Furthermore, the first thermal insulation filler and the second thermal insulation filler independently include any one or a combination of silica aerogel and white carbon black; the average particle size of the first thermal insulation filler and the second thermal insulation filler is independently 5-100nm; the thickness of the polyimide thermal insulation base film is 15-120μm; the thickness of the polyimide thermal insulation fiber film is 50-200μm; the thickness of the metal reflective layer is 0.5-2μm.

[0030] Furthermore, the polyimide fiber filaments in the polyimide fiber membrane have holes in an open or closed state; the specific surface area of ​​the polyimide fiber membrane is greater than or equal to 500m 2 / g; the average diameter of the polyimide fiber filaments in the polyimide fiber membrane is 50-900nm.

[0031] The present invention also provides a method for preparing a polyimide-based composite thermal insulation film laminate material structure, comprising: performing surface treatment on a first thermal insulation filler using a first coupling agent, mixing the first thermal insulation filler with a first polyamic acid adhesive solution, coating the first thermal insulation filler with a pore-forming agent and a second polyamic acid adhesive solution, electrospinning the second thermal insulation filler and drying the second thermal insulation filler to obtain a nanofiber membrane; performing stacking and imidization between the composite adhesive film and the nanofiber membrane using a crosslinking agent solution to obtain a polyimide composite film (a two-layer material of a polyimide thermal insulation base film / polyimide thermal insulation fiber membrane); and depositing a metal reflective layer on the side of the polyimide composite film facing away from the nanofiber membrane to obtain a polyimide-based composite thermal insulation film.

[0032] In the implementation, the first thermal insulation filler is infiltrated, modified, dispersed, filtered and dried in an alcohol aqueous solution containing a first coupling agent to obtain a surface-modified first thermal insulation filler, wherein the alcohol aqueous solution is a mixture of water and a low-molecular alcohol, and the mass ratio of water to the low-molecular alcohol is (0.5-2): (9.5-8), and the low-molecular alcohol is any one or a combination of methanol, ethanol, and isopropanol; the second thermal insulation filler is infiltrated, modified, dispersed, filtered and dried in an alcohol aqueous solution containing a second coupling agent to obtain a surface-modified second thermal insulation filler, wherein the alcohol aqueous solution is a mixture of water and a low-molecular alcohol, and the mass ratio of water to the low-molecular alcohol is (0.5-2): (9.5-8), and the low-molecular alcohol is any one or a combination of methanol, ethanol, and isopropanol;

[0033] Furthermore, using dibasic acid anhydride and diamine monomers as raw materials, a first polyamic acid glue and a second polyamic acid glue are independently synthesized by solution condensation in a polar aprotic solvent; the dibasic acid anhydride is any one or a combination of pyromellitic anhydride, 3,3',4,4'-dibenzophenone tetracarboxylic anhydride, 4,4'-oxydiphthalic anhydride, 3,3,4,4-diphenylsulfone tetracarboxylic anhydride, 3,3',4,4'-biphenyltetracarboxylic anhydride, and 2,3,3',4'-biphenyltetracarboxylic anhydride; the diamine is 4,4'-diaminodiphenyl ether, p-phenylenediamine, Any one or a combination of 4,4-diaminobiphenyl, 3,4'-diaminodiphenyl ether, m-phenylenediamine, 4,4'-diaminodiphenyl sulfone, 1,4-bis(4-aminophenoxy)benzene, 1,3-bis(3-aminophenoxy)benzene; the molar ratio of the dibasic acid anhydride to the diamine is (1-1.01):1; the polar aprotic solvent is any one or a combination of N,N-dimethylacetamide, N,N-dimethylformamide, N-methylpyrrolidone, and dimethyl sulfoxide; the solid contents of the first polyamic acid glue and the second polyamic acid glue are independently 5-25%;

[0034] In the implementation, the first thermal insulation filler modified by surface treatment is added to the second polyamic acid glue at a ratio of 5-50% by mass; the pore-forming agent for promoting the formation of pores is any one or a combination of polyvinyl pyrrolidone, polystyrene, and polymethyl methacrylate; the mass fraction ratio of the second thermal insulation filler modified by surface treatment, the pore-forming agent, and the second polyamic acid glue is (5-35%): (2-20%): (45-93%);

[0035] Furthermore, the first coupling agent and the second coupling agent are independently at least one of a phthalate coupling agent and an amino-functional silane coupling agent, wherein the phthalate coupling agent is at least one of PN-130, PN-101, and PN-102; and the amino-functional silane coupling agent is at least one of KH-540, KH-550, KH-560, KH-570, and KH-602.

[0036] Furthermore, the amount of the first coupling agent is 0.5-2% of the mass of the first thermal insulation filler; the amount of the second coupling agent is 0.5-2% of the mass of the second thermal insulation filler.

[0037] Further, the crosslinking agent is any one or a combination of trimesoyl chloride, triisocyanate, polymaleic anhydride, 1,3,5-tris(4-aminophenoxy)benzene, and melamine, and the amount of the crosslinking agent is 10-50 μL / cm 2 .

[0038] Furthermore, the metal reflective layer is any one of aluminum, copper, silver and gold, and the metal reflective layer is prepared by any one of vacuum evaporation and vacuum sputtering.

[0039] Example 1

[0040] This embodiment 1 provides a method for preparing a polyimide-based composite thermal insulation film laminate material, comprising the following steps:

[0041] (1) The silica aerogel thermal insulation filler is infiltrated, modified, dispersed, filtered, and dried in an alcohol aqueous solution containing a KH550 surface modifier (the mass ratio of water to ethanol is 1:9) to obtain a surface-modified silica aerogel thermal insulation filler.

[0042] (2) Using pyromellitic anhydride and 4,4'-diaminodiphenyl ether as raw materials (molar ratio of 1.01:1), a polyamic acid adhesive solution with a solid content of 25% was synthesized by solution polycondensation in a polar aprotic solvent N,N-dimethylacetamide.

[0043] (3) adding 30% by mass of the surface-modified silica aerogel thermal insulation filler obtained in step (1) to the polyamic acid adhesive solution obtained in step (2), stirring, dispersing, filtering and vacuum degassing to obtain a polyamic acid composite adhesive solution containing the surface-modified silica aerogel thermal insulation filler; then coating the solution on a smooth and clean glass plate to form a film, placing the film in a blast drying oven, and treating the film at 100° C. for 1 hour. After cooling, removing the smooth and clean glass plate, and obtaining a polyamic acid composite adhesive film with a residual solvent content of 23%.

[0044] (4) The polyvinyl pyrrolidone pore-forming agent, the surface-modified silica aerogel thermal insulation filler obtained in step (1), and the polyamic acid adhesive obtained in step (2) are mixed in a mass fraction of 5%:15%:80%, and the mixture is dispersed by stirring, filtered, and vacuum degassed to obtain a polyamic acid composite adhesive containing a surface-modified thermal insulation filler and a pore-forming agent; then, at a temperature of 25°C and a humidity of 50RH%, a polyamic acid nanofiber membrane containing a surface-modified thermal insulation filler and a pore-forming agent is obtained by electrospinning; the membrane is treated in a forced air drying oven at 80°C for 1 hour to obtain a polyamic acid nanofiber membrane having a solvent residue of 20%.

[0045] (5) The materials are stacked from bottom to top as follows: a smooth and clean glass plate with a thickness of 15 mm, a polyamic acid composite adhesive film with a solvent residue of 23% obtained in step (3) (and a 20 μL / cm 2 The four layers are gradually heated to 420°C in a forced imidization furnace for thermal imidization. After the furnace temperature is cooled, the smooth and clean glass plates on both sides of the four layers are removed to obtain a polyimide thermal insulation base film / polyimide thermal insulation fiber film two-layer material.

[0046] (6) The two-layer material of polyimide thermal insulation base film / polyimide thermal insulation fiber film obtained in step (5) is transferred to a magnetron sputtering coating apparatus, with the polyimide thermal insulation base film surface facing upward, and pre-sputtered for 320 seconds and sputtered for 1500 seconds at a rotation speed of 12 r / min and a power of 200 W to deposit an aluminum metal reflective layer to obtain a polyimide-based composite thermal insulation film laminate material.

[0047] The polyimide-based composite thermal insulation film laminate material consists of a polyimide thermal insulation base film, a polyimide thermal insulation fiber film and a metal reflective layer. The thickness of the polyimide thermal insulation base film is 62μm; the thickness of the polyimide thermal insulation fiber film is 150μm, and the specific surface area is 840m 2 / g, the average diameter of the polyimide fiber is 570nm; the thickness of the metal aluminum reflective layer is 1.4μm.

[0048] Example 2

[0049] This embodiment 2 provides a method for preparing a polyimide-based composite thermal insulation film laminate material, which is different from the embodiment 1 in that:

[0050] (4) The polymethyl methacrylate pore-forming agent, the surface-modified silica aerogel thermal insulation filler obtained in step (1), and the polyamic acid adhesive obtained in step (2) are mixed in a mass fraction of 10%:20%:70%, and the mixture is dispersed by stirring, filtered, and vacuum degassed to obtain a polyamic acid composite adhesive containing a surface-modified thermal insulation filler and a pore-forming agent; then, at a temperature of 25°C and a humidity of 50RH%, a polyamic acid nanofiber membrane containing a surface-modified thermal insulation filler and a pore-forming agent is obtained by electrospinning; the membrane is treated in a forced air drying oven at 80°C for 1 hour to obtain a polyamic acid nanofiber membrane having a solvent residue of 20%.

[0051] The polyimide-based composite thermal insulation film laminate material consists of a polyimide thermal insulation base film, a polyimide thermal insulation fiber film and a metal reflective layer. The thickness of the polyimide thermal insulation base film is 62μm; the thickness of the polyimide thermal insulation fiber film is 150μm, and the specific surface area is 1040m 2 / g, the average diameter of the polyimide fiber is 640nm; the thickness of the metal aluminum reflective layer is 1.4μm.

[0052] Example 3

[0053] This embodiment 3 provides a method for preparing a polyimide-based composite thermal insulation film laminate material, which is different from the embodiment 1 in that:

[0054] (3) Adding the surface-modified silica aerogel thermal insulation filler obtained in step (1) to the polyamic acid adhesive solution obtained in step (2) at a mass percentage of 25%, stirring, dispersing, filtering and vacuum degassing to obtain a polyamic acid composite adhesive solution containing the surface-modified silica aerogel thermal insulation filler; then coating the film on a smooth and clean glass plate, placing the film in a blast drying oven, and treating it at 110° C. for 50 minutes. After cooling, the smooth and clean glass plate is removed to obtain a polyamic acid composite adhesive film with a solvent residue of 18%.

[0055] The polyimide-based composite thermal insulation film laminate material consists of a polyimide thermal insulation base film, a polyimide thermal insulation fiber film and a metal reflective layer. The thickness of the polyimide thermal insulation base film is 55 μm; the thickness of the polyimide thermal insulation fiber film is 150 μm, and the specific surface area is 1040 m 2 / g, the average diameter of the polyimide fiber is 640nm; the thickness of the metal aluminum reflective layer is 1.4μm.

[0056] Example 4

[0057] This embodiment 4 provides a method for preparing a polyimide-based composite thermal insulation film laminate material, which is different from the embodiment 1 in that:

[0058] (5) The materials are stacked from bottom to top as follows: a smooth and clean glass plate with a thickness of 15 mm, a polyamic acid composite adhesive film with a solvent residue of 23% obtained in step (3) (and a 25 μL / cm 2 triisocyanate solution), a polyamic acid nanofiber membrane with a solvent residue of 20% obtained in step (4), and another smooth and clean glass plate with a thickness of 15 mm. The above four layers are gradually heated to 420°C in a forced imidization furnace for thermal imidization treatment. After the furnace temperature is cooled, the smooth and clean glass plates on both sides of the four layers are removed to obtain a polyimide thermal insulation base membrane / polyimide thermal insulation fiber membrane two-layer material.

[0059] The polyimide-based composite thermal insulation film laminate material consists of a polyimide thermal insulation base film, a polyimide thermal insulation fiber film and a metal reflective layer. The thickness of the polyimide thermal insulation base film is 62μm; the thickness of the polyimide thermal insulation fiber film is 150μm, and the specific surface area is 840m 2 / g, the average diameter of the polyimide fiber is 570nm; the thickness of the metal aluminum reflective layer is 1.4μm.

[0060] Comparative Example 1

[0061] This comparative example 1 provides a method for preparing a two-layer material of a polyimide thermal insulation base film / polyimide thermal insulation fiber film, which is different from that of Example 1 in that:

[0062] Step (6) is not performed, and after completing step (5), a two-layer material of polyimide thermal insulation base film / polyimide thermal insulation fiber film is obtained.

[0063] The polyimide two-layer material consists of a polyimide thermal insulation base film and a polyimide thermal insulation fiber film. The thickness of the polyimide thermal insulation base film is 62μm; the thickness of the polyimide thermal insulation fiber film is 150μm, and the specific surface area is 840m 2 / g, and the average diameter of the polyimide fiber is 570nm.

[0064] Comparative Example 2

[0065] This comparative example 2 provides a method for preparing a polyimide-based composite thermal insulation film base layer, which is different from that of example 1 in that:

[0066] After completing steps (1), (2) and (3), the polyamic acid composite adhesive film obtained in step (3) is gradually heated to 420° C. in a forced imidization furnace for thermal imidization treatment. After the furnace temperature is cooled, a polyimide thermal insulation base film material is obtained.

[0067] The thickness of the polyimide thermal insulation base film material is 62 μm.

[0068] Comparative Example 3

[0069] This comparative example 3 provides a method for preparing a polyimide thermal insulation fiber membrane material, which is different from that of example 1 in that:

[0070] After completing steps (1), (2) and (4), the polyamic acid nanofiber membrane obtained in step (4) is gradually heated to 420° C. in a forced imidization furnace for thermal imidization treatment. After the furnace temperature is cooled, a polyimide thermal insulation fiber membrane material is obtained.

[0071] The thickness of the polyimide thermal insulation fiber membrane material is 150μm and the specific surface area is 840m 2 / g, and the average diameter of the polyimide fiber is 570nm.

[0072] Comparative Example 4

[0073] This comparative example 4 provides a method for preparing a polyimide heat insulation base film / metal reflective layer two-layer material, which is different from that of Example 1 in that:

[0074] After completing steps (1), (2) and (3), the polyamic acid composite adhesive film obtained in step (3) is gradually heated to 420° C. in a forced imidization furnace for thermal imidization treatment. After the furnace temperature is cooled, a polyimide thermal insulation base film material is obtained. Subsequently, step (6) is performed to obtain a polyimide thermal insulation base film / metal reflective layer two-layer material.

[0075] The polyimide two-layer material is composed of a polyimide heat-insulating base film and a metal reflective layer. The thickness of the polyimide heat-insulating base film is 62 μm; the thickness of the metal aluminum reflective layer is 1.4 μm.

[0076] Comparative Example 5

[0077] This comparative example 5 provides a method for preparing a composite thermal insulation film laminate material of a polyimide thermal insulation base film / polyimide thermal insulation fiber film / metal reflective layer structure, which is different from that of Example 1 in that:

[0078] In step (5), the polyamic acid composite film is not coated with 20 μL / cm 2 Application of trimesoyl chloride solution.

[0079] The polyimide-based composite thermal insulation film laminate material consists of a polyimide thermal insulation base film, a polyimide thermal insulation fiber film and a metal reflective layer. The thickness of the polyimide thermal insulation base film is 62μm; the thickness of the polyimide thermal insulation fiber film is 150μm, and the specific surface area is 840m 2 / g, the average diameter of the polyimide fiber is 570nm; the thickness of the metal aluminum reflective layer is 1.4μm.

[0080] Performance Testing

[0081] Mechanical properties:

[0082] The thermal insulation polyimide composite films prepared in Examples 1 to 4 and Comparative Examples 1 to 5 were subjected to a tensile strength test, and the test was carried out in accordance with ASTM D882 standard.

[0083] Thermal insulation performance:

[0084] The thermal conductivity of the polyimide composite thermal insulation film materials obtained in Examples 1-4 and Comparative Examples 5-9 was measured using a Hot Disk 2500S thermal constant analyzer.

[0085] The polyimide composite thermal insulation film materials obtained in Examples 1-4 and Comparative Examples 1-5 were subjected to infrared imaging analysis. The polyimide composite thermal insulation film material sample was placed close to the center of a 150mm*150mm heating platform, the heating temperature was 100°C, and an infrared thermal imager was used to measure the surface temperature of the polyimide composite thermal insulation film material sample from directly above the sample at the 3-minute stabilization moment.

[0086] Table 1

[0087]

[0088] Comparative Example 1 is a two-layer material of polyimide thermal insulation base film / polyimide thermal insulation fiber film; Comparative Example 2 is a polyimide thermal insulation base film material; Comparative Example 3 is a polyimide thermal insulation fiber film material; Comparative Example 4 is a two-layer material of polyimide thermal insulation base film / metal reflective layer; Comparative Example 5 is a composite thermal insulation film laminate material of polyimide thermal insulation base film / polyimide thermal insulation fiber film / metal reflective layer structure without the application of a cross-linking agent.

[0089] As can be seen from Table 1, the polyimide-based composite thermal insulation film laminated materials of the structure of polyimide thermal insulation base film / polyimide thermal insulation fiber film / metal reflective layer prepared in Examples 1 to 4 provided in the present application have a tensile strength similar to that of the polyimide thermal insulation base film material (Comparative Example 2) and significantly higher than that of the polyimide thermal insulation fiber film material (Comparative Example 3) due to the high temperature resistant mechanical support of the polyimide thermal insulation base film. During the mechanical stretching process, the polyimide thermal insulation base film / polyimide thermal insulation fiber film / metal reflective layer structure of the polyimide-based composite thermal insulation film laminated materials prepared in Examples 1 to 4, the polyimide thermal insulation base film and the polyimide thermal insulation fiber film interpenetrate at the interface, and the three-dimensional cross-linked network structure polyimide molecular chains are interlaced and anchored, thus forming a strong interface bond. During the mechanical stretching process, there is no obvious separation phenomenon between the two layers of the polyimide thermal insulation base film and the polyimide thermal insulation fiber film.

[0090] In the composite thermal insulation film laminate material (Comparative Example 5) of the structure of polyimide thermal insulation base film / polyimide thermal insulation fiber film / metal reflective layer without the use of a crosslinking agent, although the interface between the polyimide thermal insulation base film and the polyimide thermal insulation fiber film will also form interpenetration due to the interlacing of polyimide molecular chains. However, in the absence of a crosslinking agent, a three-dimensional crosslinked network structure cannot be formed, and only linear molecular chains are connected, resulting in a relatively weak interface. During the mechanical stretching process, the polyimide thermal insulation base film and the polyimide thermal insulation fiber film are separated in advance, and the fiber film layer falls off.

[0091] As can be seen from Table 1, compared with the polyimide insulation base film / polyimide insulation fiber film two-layer material (Comparative Example 1), the polyimide insulation base film material (Comparative Example 2), the polyimide insulation fiber film material (Comparative Example 3), and the polyimide insulation base film / metal reflective layer two-layer material (Comparative Example 4), the polyimide-based composite thermal insulation film laminate material of the polyimide insulation base film / polyimide insulation fiber film / metal reflective layer structure prepared in Examples 1 to 4 provided in the present application, the polyimide insulation base film is a thermal convection protection layer, the polyimide insulation fiber film is a heat conduction barrier layer, and the metal reflective layer is a thermal radiation protection layer, showing a relatively excellent thermal insulation effect.

[0092] The polyimide-based composite thermal insulation film laminate material of the structure of polyimide thermal insulation base film / polyimide thermal insulation fiber film / metal reflective layer prepared in Examples 1 to 4 provided in the present application has the same laminate structure design as the composite thermal insulation film laminate material of the structure of polyimide thermal insulation base film / polyimide thermal insulation fiber film / metal reflective layer without the application of a cross-linking agent (Comparative Example 5), and the thermal insulation properties of the two are similar.

[0093] Please refer to Figure 1-Figure 4 In summary, the present invention prepares a polyimide-based composite thermal insulation film laminate material through a laminate structure design of polyimide thermal insulation base film / polyimide thermal insulation fiber film / metal reflective layer. The polyimide thermal insulation base film is a high temperature resistant support layer and a heat convection protection layer, the polyimide thermal insulation fiber film is a heat conduction barrier layer, the metal reflective layer is a heat radiation protection layer, the polyimide thermal insulation base film and the polyimide thermal insulation fiber film are mutually infiltrated at the interface, and the three-dimensional cross-linked network structure polyimide molecular chains are interlaced and anchored, thereby achieving the polyimide-based composite thermal insulation film laminate material of the polyimide thermal insulation base film / polyimide thermal insulation fiber film / metal reflective layer structure provided by the present application having the excellent effects of high mechanical strength, high film layer bonding strength, and high thermal insulation performance.

[0094] It should be noted that, in this article, if there are first and second, etc., relational terms are only used to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Moreover, the terms "include", "comprise" or any other variants thereof are intended to cover non-exclusive inclusion, so that a process, method, article or device including a series of elements includes not only those elements, but also other elements not explicitly listed, or also includes elements inherent to such process, method, article or device. In the absence of further restrictions, the elements defined by the sentence "comprise a ..." do not exclude the existence of other identical elements in the process, method, article or device including the elements.

[0095] The above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit the same. Although the present invention has been described in detail with reference to the aforementioned embodiments, a person skilled in the art should understand that the technical solutions described in the aforementioned embodiments may still be modified, or some of the technical features may be replaced by equivalents. However, these modifications or replacements do not deviate the essence of the corresponding technical solutions from the spirit and scope of the technical solutions of the embodiments of the present invention.

[0096] Although the embodiments of the present invention are described in detail above, it is obvious to those skilled in the art that various modifications and variations can be made to these embodiments. However, it should be understood that such modifications and variations are within the scope and spirit of the present invention as described in the claims. Moreover, the present invention described herein may have other embodiments and may be implemented or realized in a variety of ways.

Claims

1. A polyimide-based composite thermal insulation film laminate material structure, characterized in that: It includes a cross-linked polyimide thermal insulation base film and a polyimide thermal insulation fiber film, wherein a metal reflective layer is deposited on the side of the polyimide thermal insulation base film facing away from the polyimide thermal insulation fiber film; wherein the polyimide thermal insulation base film includes a polyimide base film and a first thermal insulation filler dispersed in the polyimide base film, and the polyimide thermal insulation fiber membrane includes a polyimide fiber membrane formed by electrospinning and a second thermal insulation filler embedded in the polyimide fiber membrane.

2. The polyimide-based composite thermal insulation film laminate material structure according to claim 1, characterized in that: The first thermal insulation filler and the second thermal insulation filler independently include any one or a combination of silica aerogel and white carbon black; the average particle sizes of the first thermal insulation filler and the second thermal insulation filler are independently 5-100nm; the thickness of the polyimide thermal insulation base film is 15-120μm; the thickness of the polyimide thermal insulation fiber film is 50-200μm; the thickness of the metal reflective layer is 0.5-2μm.

3. The polyimide-based composite thermal insulation film laminate material structure according to claim 1, characterized in that: The polyimide fiber filaments in the polyimide fiber membrane have holes in an open or closed state; the specific surface area of ​​the polyimide fiber membrane is greater than or equal to 500m 2 / g; the average diameter of the polyimide fiber filaments in the polyimide fiber membrane is 50-900nm.

4. A method for preparing a polyimide-based composite thermal insulation film laminate material structure, characterized in that: A first thermal insulation filler is surface treated with a first coupling agent and then mixed with a first polyamic acid adhesive solution, coated to form a film and dried to obtain a composite adhesive film; a second thermal insulation filler is surface treated with a second coupling agent and then mixed with a pore-forming agent and a second polyamic acid adhesive solution, electrospun and dried to obtain a nanofiber membrane; the composite adhesive film and the nanofiber membrane are stacked and imidized with a cross-linking agent solution to obtain a polyimide composite membrane; a metal reflective layer is deposited on the side of the polyimide composite membrane facing away from the nanofiber membrane to obtain a polyimide-based composite thermal insulation film.

5. The method for preparing a polyimide-based composite thermal insulation film laminate material structure according to claim 4, characterized in that: The first coupling agent and the second coupling agent are independently at least one of a phthalate coupling agent and an amino-functional silane coupling agent, wherein the phthalate coupling agent is at least one of PN-130, PN-101, and PN-102; and the amino-functional silane coupling agent is at least one of KH-540, KH-550, KH-560, KH-570, and KH-602.

6. The method for preparing a polyimide-based composite thermal insulation film laminate material structure according to claim 4, characterized in that: The invention adopts dibasic acid anhydride and diamine monomers as raw materials, and independently synthesizes a first polyamic acid glue solution and a second polyamic acid glue solution by solution condensation in a polar aprotic solvent; the dibasic acid anhydride is any one of pyromellitic acid anhydride, 3,3',4,4'-dibenzophenone tetracarboxylic acid anhydride, 4,4'-oxydiphthalic anhydride, 3,3,4,4-diphenyl sulfone tetracarboxylic acid anhydride, 3,3',4,4'-biphenyl tetracarboxylic acid anhydride, and 2,3,3',4'-biphenyl tetracarboxylic acid anhydride or a combination thereof; the diamine is 4,4'-diaminodiphenyl ether, p-phenylenediamine, 4,4 -diaminobiphenyl, 3,4'-diaminodiphenyl ether, m-phenylenediamine, 4,4'-diaminodiphenyl sulfone, 1,4-bis(4-aminophenoxy)benzene, 1,3-bis(3-aminophenoxy)benzene, or a combination thereof; the molar ratio of the dibasic acid anhydride to the diamine is (1-1.01):1; the polar aprotic solvent is any one or a combination of N,N-dimethylacetamide, N,N-dimethylformamide, N-methylpyrrolidone, and dimethyl sulfoxide; the solid contents of the first polyamic acid glue and the second polyamic acid glue are independently 5-25%.

7. The method for preparing a polyimide-based composite thermal insulation film laminated material structure according to claim 4, characterized in that: The amount of the first coupling agent is 0.5-2% of the mass of the first thermal insulation filler; the amount of the second coupling agent is 0.5-2% of the mass of the second thermal insulation filler.

8. The method for preparing a polyimide-based composite thermal insulation film laminate material structure according to claim 4, characterized in that: The crosslinking agent is any one of trimesoyl chloride, triisocyanate, polymaleic anhydride, 1,3,5-tris(4-aminophenoxy)benzene, and melamine, or a combination thereof, and the amount of the crosslinking agent is 10-50 μL / cm 2 .

9. The method for preparing a polyimide-based composite thermal insulation film laminate material structure according to claim 4, characterized in that: The metal reflective layer is any one of aluminum, copper, silver and gold, and the metal reflective layer is prepared by any one of vacuum evaporation and vacuum sputtering.

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