High-thermal-oxygen-stable polyimide composite film and preparation method thereof

Abstract

The application provides a high thermal and oxidative stability polyimide composite film and a preparation method thereof.The high thermal and oxidative stability polyimide composite film comprises a non-thermoplastic polyimide layer and a first thermoplastic polyimide layer, and the first thermoplastic polyimide layer is located on the first side of the non-thermoplastic polyimide layer; the non-thermoplastic polyimide layer and the first thermoplastic polyimide layer both contain rare earth oxides; and the first thermoplastic polyimide layer contains a toughening agent with a -COOH, -N-H or -C=O polar group.The film is modified by the toughening agent, the bonding strength is improved, the overall thermal and oxidative stability of the film is improved by the rare earth oxides, and the adverse influence of the toughening agent on the mechanical properties of the resin is reduced as much as possible, so that the thermal and oxidative stability of the film is improved as a whole.

Description

TECHNICAL FIELD

[0001] The present application relates to a high thermal and oxidative stability polyimide composite film and a method for preparing the same, for example, to a high thermal and oxidative stability co-extrusion polyimide composite film and a method for preparing the same, which can be used for a flexible printed circuit board. BACKGROUND

[0002] In recent years, as electronic products are becoming lighter, smaller and higher in density, the demand for various printed boards, especially flexible printed circuit boards, is gradually increasing. Using two or more layers of polyimide as a flexible substrate can effectively improve the performance of the circuit board. Generally, a polyamide acid solution is coated on the surface of a polyimide film and imidized by heating to obtain a composite polyimide film. This method has many steps and high cost, so a composite polyimide film (also referred to as a "co-extrusion polyimide composite film") can be manufactured by simultaneously casting two or more layers of polyamide acid solution on a support, peeling the cast layers from the support after drying, and performing heat treatment, which greatly simplifies the steps.

[0003] In addition, high thermal resistance is required in the soldering process when forming a circuit board, which puts higher requirements on the reliability and service life of the polyimide composite material, and the polyimide composite material needs to have better thermal oxidative stability. SUMMARY

[0004] Currently, rare earth oxides are used to improve the thermal oxidative stability of rubber and plastic, and show very effective modification effect. Specifically, the large radius of rare earth ions makes the electron energy level abundant, and the large number of empty orbits of the outer layer of rare earth elements makes them have strong coordination ability, which provides appropriate conditions for the complexation reaction of rare earth elements to generate corresponding complexes. The formation of such complexes has a certain improvement effect on the thermal oxidative resistance of high polymer materials, so rare earth is used as a stabilizer to improve the thermal oxidative resistance of high polymer materials.

[0005] The present application provides a high thermal and oxidative stability polyimide composite film, comprising: a non-thermoplastic polyimide layer and a first thermoplastic polyimide layer, the first thermoplastic polyimide layer being located on a first side of the non-thermoplastic polyimide layer; the non-thermoplastic polyimide layer containing rare earth oxides; the first thermoplastic polyimide layer containing rare earth oxides and a toughening agent with -COOH, -N-H or -C=O polar groups.

[0006] In an example, the high-thermo-oxidative-stability polyimide composite film further comprises: a second thermoplastic polyimide layer, the second thermoplastic polyimide layer containing rare earth oxide and toughening agent with -COOH, -N-H or -C=O polar group; wherein the second thermoplastic polyimide layer is located on a second side of the non-thermoplastic polyimide layer, so that the non-thermoplastic polyimide layer is located between the first thermoplastic polyimide layer and the second thermoplastic polyimide layer, or the second thermoplastic polyimide layer is located on a first side of the non-thermoplastic polyimide layer, so that the first thermoplastic polyimide layer is located between the non-thermoplastic polyimide layer and the second thermoplastic polyimide layer.

[0007] In an example, the rare earth oxide in the non-thermoplastic polyimide layer comprises one or more of lanthanum oxide, cerium oxide, praseodymium oxide, neodymium oxide, promethium oxide, samarium oxide, europium oxide, gadolinium oxide, terbium oxide, dysprosium oxide, holmium oxide, erbium oxide, thulium oxide, ytterbium oxide, lutetium oxide, yttrium oxide, scandium oxide; the rare earth oxide in the first thermoplastic polyimide layer comprises one or more of lanthanum oxide, cerium oxide, praseodymium oxide, neodymium oxide, promethium oxide, samarium oxide, europium oxide, gadolinium oxide, terbium oxide, dysprosium oxide, holmium oxide, erbium oxide, thulium oxide, ytterbium oxide, lutetium oxide, yttrium oxide, scandium oxide; and / or, the rare earth oxide in the second thermoplastic polyimide layer comprises one or more of lanthanum oxide, cerium oxide, praseodymium oxide, neodymium oxide, promethium oxide, samarium oxide, europium oxide, gadolinium oxide, terbium oxide, dysprosium oxide, holmium oxide, erbium oxide, thulium oxide, ytterbium oxide, lutetium oxide, yttrium oxide, scandium oxide.

[0008] In an example, the toughening agent in the first thermoplastic polyimide layer comprises modified acrylate polymer; and / or, the toughening agent in the second thermoplastic polyimide layer comprises modified acrylate polymer.

[0009] In an example, the rare earth oxide in the non-thermoplastic polyimide layer accounts for 2 to 11% by weight based on the total weight of the non-thermoplastic polyimide layer; the rare earth oxide in the first thermoplastic polyimide layer accounts for 2 to 11% by weight based on the total weight of the first thermoplastic polyimide layer; and / or, the rare earth oxide in the second thermoplastic polyimide layer accounts for 2 to 11% by weight based on the total weight of the second thermoplastic polyimide layer.

[0010] In an example, the toughening agent in the first thermoplastic polyimide layer accounts for 7 to 16% by weight based on the total weight of the first thermoplastic polyimide layer; and / or, the toughening agent in the second thermoplastic polyimide layer accounts for 7 to 16% by weight based on the total weight of the second thermoplastic polyimide layer.

[0011] For example, the weight ratio between the rare earth oxide in the first thermoplastic polyimide layer and the toughening agent in the first thermoplastic polyimide layer is 1:(0.64 to 8); and / or, the weight ratio between the rare earth oxide in the second thermoplastic polyimide layer and the toughening agent in the second thermoplastic polyimide layer is 1:(0.64 to 8).

[0012] For example, the 5% thermal decomposition temperature (T d 5%) of the high-thermal-oxygen-stability polyimide composite film is 480 to 537℃.

[0013] The present application also provides a preparation method of the high-thermal-oxygen-stability polyimide composite film, comprising: providing a non-thermoplastic polyamic acid solution and a first thermoplastic polyamic acid solution, wherein the non-thermoplastic polyamic acid solution contains rare earth oxide, and the first thermoplastic polyamic acid solution contains rare earth oxide and a toughening agent with -COOH, -N-H or -C=O polar group; co-extruding the non-thermoplastic polyamic acid solution and the first thermoplastic polyamic acid solution to obtain a co-extrusion casting sheet, wherein the co-extrusion casting sheet comprises a non-thermoplastic polyamic acid layer and a first thermoplastic polyamic acid layer, and the first thermoplastic polyamic acid layer is located on a first side of the non-thermoplastic polyamic acid layer; and imidizing the co-extrusion casting sheet to obtain the high-thermal-oxygen-stability polyimide composite film.

[0014] The application also provides a preparation method of the high thermal and oxidative stability polyimide composite film, comprising: providing a non-thermoplastic polyamic acid solution, a first thermoplastic polyamic acid solution and a second thermoplastic polyamic acid solution, wherein the non-thermoplastic polyamic acid solution contains rare earth oxide, the first thermoplastic polyamic acid solution contains rare earth oxide and toughening agent with -COOH, -N-H or -C=O polar group, and the second thermoplastic polyamic acid solution contains rare earth oxide and toughening agent with -COOH, -N-H or -C=O polar group; co-extruding the non-thermoplastic polyamic acid solution, the first thermoplastic polyamic acid solution and the second thermoplastic polyamic acid solution to obtain a co-extrusion casting sheet, wherein the co-extrusion casting sheet comprises a non-thermoplastic polyamic acid layer, a first thermoplastic polyamic acid layer and a second thermoplastic polyamic acid layer; the first thermoplastic polyamic acid layer is located on a first side of the non-thermoplastic polyamic acid layer; the second thermoplastic polyamic acid layer is located on a second side of the non-thermoplastic polyamic acid layer, so that the non-thermoplastic polyamic acid layer is located between the first thermoplastic polyamic acid layer and the second thermoplastic polyamic acid layer, or the second thermoplastic polyamic acid layer is located on the first side of the non-thermoplastic polyamic acid layer, so that the first thermoplastic polyamic acid layer is located between the non-thermoplastic polyamic acid layer and the second thermoplastic polyamic acid layer; and subjecting the co-extrusion casting sheet to imidization to obtain the high thermal and oxidative stability polyimide composite film.

[0015] For example, the rare earth oxide in the non-thermoplastic polyamic acid solution comprises one or more of lanthanum oxide, cerium oxide, praseodymium oxide, neodymium oxide, promethium oxide, samarium oxide, europium oxide, gadolinium oxide, terbium oxide, dysprosium oxide, holmium oxide, erbium oxide, thulium oxide, ytterbium oxide, lutetium oxide, yttrium oxide and scandium oxide; the rare earth oxide in the first thermoplastic polyamic acid solution comprises one or more of lanthanum oxide, cerium oxide, praseodymium oxide, neodymium oxide, promethium oxide, samarium oxide, europium oxide, gadolinium oxide, terbium oxide, dysprosium oxide, holmium oxide, erbium oxide, thulium oxide, ytterbium oxide, lutetium oxide, yttrium oxide and scandium oxide; and / or, the rare earth oxide in the second thermoplastic polyamic acid solution comprises one or more of lanthanum oxide, cerium oxide, praseodymium oxide, neodymium oxide, promethium oxide, samarium oxide, europium oxide, gadolinium oxide, terbium oxide, dysprosium oxide, holmium oxide, erbium oxide, thulium oxide, ytterbium oxide, lutetium oxide, yttrium oxide and scandium oxide.

[0016] For example, the toughening agent in the first thermoplastic polyamic acid solution comprises modified acrylate polymer; and / or, the toughening agent in the second thermoplastic polyamic acid solution comprises modified acrylate polymer.

[0017] For example, the non-thermoplastic polyamide acid solution further comprises a hardening agent; the first thermoplastic polyamide acid solution further comprises a hardening agent; and / or, the second thermoplastic polyamide acid solution further comprises a hardening agent.

[0018] For example, the hardening agent in the non-thermoplastic polyamide acid solution comprises one or more of acetic anhydride, isoquinoline, N,N-dimethylformamide; the hardening agent in the first thermoplastic polyamide acid solution comprises one or more of acetic anhydride, isoquinoline, N,N-dimethylformamide; and / or, the hardening agent in the second thermoplastic polyamide acid solution comprises one or more of acetic anhydride, isoquinoline, N,N-dimethylformamide.

[0019] For example, the weight ratio between the rare earth oxide in the first thermoplastic polyamide acid solution and the toughening agent in the first thermoplastic polyamide acid solution is 1:(0.64 to 8); and / or, the weight ratio between the rare earth oxide in the second thermoplastic polyamide acid solution and the toughening agent in the second thermoplastic polyamide acid solution is 1:(0.64 to 8).

[0020] For example, the imidization comprises: heating the co-extrusion cast sheet.

[0021] In the present application, the film is modified by a toughening agent with -COOH, -N-H or -C=O polar groups to improve its bonding strength; and, the overall heat-oxidation stability of the film is further improved by rare earth oxides, while trying to minimize the adverse effects on the mechanical properties of the resin. In this way, the overall heat-oxidation stability of the polyimide composite film is improved. BRIEF DESCRIPTION OF DRAWINGS

[0022] Figure 1 is a schematic diagram presenting a high heat-oxidation stability polyimide composite film of the first embodiment of the present application;

[0023] Figure 2 is a schematic diagram presenting a high heat-oxidation stability polyimide composite film of the second embodiment of the present application;

[0024] Figure 3 is a schematic diagram presenting a high heat-oxidation stability polyimide composite film of the third embodiment of the present application;

[0025] Figure 4 is a flow chart illustrating a method for preparing the above-mentioned high heat-oxidation stability polyimide composite film using co-extrusion. DETAILED DESCRIPTION

[0026] The specific embodiments of the present application are described in detail below with reference to the accompanying drawings. It should be understood that the specific embodiments described herein are merely intended to illustrate and explain the present application, and are not intended to limit the present application.

[0027] The endpoints of the ranges and any values disclosed herein are not limited to the precise values recited as the exact dimensions are not critical to the invention. Any numerical value, however, can include values up to and including the value of the lower limit, unless the context clearly indicates otherwise. Any numerical value, however, can include values up to and including the value of the lower limit, unless the context clearly indicates otherwise. The various disclosed ranges are not to be construed as without a start and end point. For ranges comprising single points, the endpoints are included in the range; for ranges comprising two points, the endpoints are included in the range; and for ranges comprising three or more points, the endpoints are included in the range.

[0028] The first embodiment of the present invention proposes a high-thermo-oxidative stability polyimide composite film, which has a heat-decomposable property, for example, has a thermal decomposition temperature (T d 5%) of 480 to 537°C, or for example, has a thermal decomposition temperature (T d 5%) of 480°C, 481°C, 482°C, 483°C, 484°C, 485°C, 486°C, 487°C, 488°C, 489°C, 490°C, 491°C, 492°C, 493°C, 494°C, 495°C, 496°C, 497°C, 498°C, 499°C, 500°C, 501°C, 502°C, 503°C, 504°C, 505°C, 506°C, 507°C, 508°C, 509°C, 510°C, 511°C, 512°C, 513°C, 514°C, 515°C, 516°C, 517°C, 518°C, 519°C, 520°C, 521°C, 522°C, 523°C, 524°C, 525°C, 526°C, 527°C, 528°C, 529°C, 530°C, 531°C, 532°C, 533°C, 534°C, 535°C, 536°C, or 537°C. As shown, the high-thermo-oxidative stability polyimide composite film comprises a non-thermoplastic polyimide layer (1) and a first thermoplastic polyimide layer (2). Figure 1 The non-thermoplastic polyimide layer (1) contains, in addition to the non-thermoplastic polyimide, a rare earth oxide.

[0029] The non-thermoplastic polyimide layer (1) contains, in addition to the non-thermoplastic polyimide, a rare earth oxide.

[0030] The term "rare earth" refers to the elements of the lanthanide series and scandium and yttrium, so the rare earth oxide herein includes, for example, one or more of lanthanum oxide, cerium oxide, praseodymium oxide, neodymium oxide, promethium oxide, samarium oxide, europium oxide, gadolinium oxide, terbium oxide, dysprosium oxide, holmium oxide, erbium oxide, thulium oxide, ytterbium oxide, lutetium oxide, yttrium oxide, and scandium oxide; preferably includes one or more of lanthanum oxide, cerium oxide, and neodymium oxide; more preferably includes neodymium oxide. The rare earth oxide herein can account for 2 to 11% by weight, for example, 2% by weight, 3% by weight, 4% by weight, 5% by weight, 6% by weight, 7% by weight, 8% by weight, 9% by weight, 10% by weight, or 11% by weight, based on the total weight of the non-thermoplastic polyimide layer (1).

[0031] To provide proper shaping of the non-thermoplastic polyimide layer (1), the non-thermoplastic polyimide layer (1) can further contain a hardening agent, which for example comprises one or more of acetic anhydride, isoquinoline, N,N-dimethylformamide.

[0032] The first thermoplastic polyimide layer (2) is located on a first side of the non-thermoplastic polyimide layer (1) and contains, in addition to the thermoplastic polyimide, a rare earth oxide and a toughener having a -COOH, -N-H or -C=O polar group.

[0033] As mentioned before, the rare earth oxide here for example comprises one or more of lanthanum oxide, cerium oxide, praseodymium oxide, neodymium oxide, promethium oxide, samarium oxide, europium oxide, gadolinium oxide, terbium oxide, dysprosium oxide, holmium oxide, erbium oxide, thulium oxide, ytterbium oxide, lutetium oxide, yttrium oxide, scandium oxide; preferably one or more of lanthanum oxide, cerium oxide, neodymium oxide; more preferably neodymium oxide. The rare earth oxide here can account for 2 to 11% by weight, for example 2%, 3%, 4%, 5%, 6%, 7%, 8%, 9%, 10%, or 11% by weight, based on the total weight of the first thermoplastic polyimide layer (2).

[0034] The toughener having a -COOH, -N-H or -C=O polar group here for example comprises a modified acrylate polymer. The toughener having a -COOH, -N-H or -C=O polar group here can account for 7 to 16% by weight, for example 7%, 8%, 9%, 10%, 11%, 12%, 13%, 14%, 15%, or 16% by weight, based on the total weight of the first thermoplastic polyimide layer (2).

[0035] In addition, with regard to the weight relationship between the rare earth oxide here and the toughener having a -COOH, -N-H or -C=O polar group here, the weight ratio between the former and the latter can be 1:(0.64 to 8), for example 1:0.64, 1:2, 1:3.5, or 1:8.

[0036] Likewise, to provide proper shaping of the first thermoplastic polyimide layer (2), the first thermoplastic polyimide layer (2) can further contain a hardening agent, which for example comprises one or more of acetic anhydride, isoquinoline, N,N-dimethylformamide.

[0037] The second and third embodiments of the present application each propose a high-thermal-oxygen-stability polyimide composite film, which has a heat-resistant decomposition property, for example has a thermal decomposition temperature (T d 5%) of 480 to 537℃, and for example has a thermal decomposition temperature (T d5% 480°C, 481°C, 482°C, 483°C, 484°C, 485°C, 486°C, 487°C, 488°C, 489°C, 490°C, 491°C, 492°C, 493°C, 494°C, 495°C, 496°C, 497°C, 498°C, 499°C, 500°C, 501°C, 502°C, 503°C, 504°C, 505°C, 506°C, 507°C, 508°C, 509°C, 510°C, 511°C, 512°C, 513°C, 514°C, 515°C, 516°C, 517°C, 518°C, 519°C, 520°C, 521°C, 522°C, 523°C, 524°C, 525°C, 526°C, 527°C, 528°C, 529°C, 530°C, 531°C, 532°C, 533°C, 534°C, 535°C, 536°C, or 537°C.

[0038] As shown in FIG. 1, the high-thermal-oxygen-stable polyimide composite film comprises a non-thermoplastic polyimide layer (1), a first thermoplastic polyimide layer (2), and a second thermoplastic polyimide layer (3). Figure 2 3 As shown in FIG. 1, the non-thermoplastic polyimide layer (1) comprises a non-thermoplastic polyimide and a rare earth oxide.

[0039] As shown in FIG. 1, the non-thermoplastic polyimide layer (1) comprises a non-thermoplastic polyimide and a rare earth oxide.

[0040] The rare earth oxide herein refers to one or more of scandium, yttrium, and lanthanide series elements of Group III, and thus the rare earth oxide herein includes, for example, one or more of lanthanum oxide, cerium oxide, praseodymium oxide, neodymium oxide, promethium oxide, samarium oxide, europium oxide, gadolinium oxide, terbium oxide, dysprosium oxide, holmium oxide, erbium oxide, thulium oxide, ytterbium oxide, lutetium oxide, yttrium oxide, and scandium oxide; preferably one or more of lanthanum oxide, cerium oxide, and neodymium oxide; and more preferably neodymium oxide. The rare earth oxide herein can account for 2 to 11% by weight, for example, 2% by weight, 3% by weight, 4% by weight, 5% by weight, 6% by weight, 7% by weight, 8% by weight, 9% by weight, 10% by weight, or 11% by weight, based on the total weight of the non-thermoplastic polyimide layer (1).

[0041] To provide proper shaping of the non-thermoplastic polyimide layer (1), the non-thermoplastic polyimide layer (1) can further comprise a hardener, which includes, for example, one or more of acetic anhydride, isoquinoline, and N,N-dimethylformamide.

[0042] As shown in FIG. 1, the first thermoplastic polyimide layer (2) is located on a first side of the non-thermoplastic polyimide layer (1) and comprises a thermoplastic polyimide, a rare earth oxide, and a toughener having a -COOH, -N-H, or -C=O polar group. Figure 2 3 As shown in FIG. 1, the first thermoplastic polyimide layer (2) is located on a first side of the non-thermoplastic polyimide layer (1) and comprises a thermoplastic polyimide, a rare earth oxide, and a toughener having a -COOH, -N-H, or -C=O polar group.

[0043] ​​As previously mentioned, the rare earth oxides herein include, for example, one or more of lanthanum oxide, cerium oxide, praseodymium oxide, neodymium oxide, promethium oxide, samarium oxide, europium oxide, gadolinium oxide, terbium oxide, dysprosium oxide, holmium oxide, erbium oxide, thulium oxide, ytterbium oxide, diurnal oxide, yttrium oxide, and scandium oxide; preferably, one or more of lanthanum oxide, cerium oxide, and neodymium oxide; more preferably, neodymium oxide. The rare earth oxides herein may account for 2 to 11% by weight of the total weight of the first thermoplastic polyimide layer (2), for example, 2% by weight, 3% by weight, 4% by weight, 5% by weight, 6% by weight, 7% by weight, 8% by weight, 9% by weight, 10% by weight, or 11% by weight.

[0044] The toughening agent having -COOH, -NH or -C=O polar groups may include, for example, a modified acrylate polymer. Based on the total weight of the first thermoplastic polyimide layer (2), the toughening agent having -COOH, -NH or -C=O polar groups may comprise 7 to 16% by weight, for example, 7% by weight, 8% by weight, 9% by weight, 10% by weight, 11% by weight, 12% by weight, 13% by weight, 14% by weight, 15% by weight, or 16% by weight.

[0045] Furthermore, regarding the weight relationship between the rare earth oxide and the toughening agent with -COOH, -NH or -C=O polar groups, the weight ratio between the former and the latter may be 1:(0.64 to 8), for example 1:0.64, 1:2, 1:3.5 or 1:8.

[0046] Similarly, to provide proper shaping of the first thermoplastic polyimide layer (2), the first thermoplastic polyimide layer (2) may further contain a hardener, which may include, for example, one or more of acetic anhydride, isoquinoline, and N,N-dimethylformamide.

[0047] like Figure 2 As shown, the second thermoplastic polyimide layer (3) is located on a second side of the non-thermoplastic polyimide layer (1), such that the non-thermoplastic polyimide layer (1) is located between the first thermoplastic polyimide layer (2) and the second thermoplastic polyimide layer (3); or, as shown Figure 3 As shown, the second thermoplastic polyimide layer (3) is located on the first side of the non-thermoplastic polyimide layer (1), such that the first thermoplastic polyimide layer (2) is located between the non-thermoplastic polyimide layer (1) and the second thermoplastic polyimide layer (3). In addition to thermoplastic polyimide, the second thermoplastic polyimide layer (3) also contains rare earth oxides and toughening agents with polar groups of -COOH, -NH or -C=O.

[0048] As previously mentioned, the rare earth oxides herein include, for example, one or more of lanthanum oxide, cerium oxide, praseodymium oxide, neodymium oxide, promethium oxide, samarium oxide, europium oxide, gadolinium oxide, terbium oxide, dysprosium oxide, holmium oxide, erbium oxide, thulium oxide, ytterbium oxide, diurnal oxide, yttrium oxide, and scandium oxide; preferably, one or more of lanthanum oxide, cerium oxide, and neodymium oxide; more preferably, neodymium oxide. The rare earth oxides herein may account for 2 to 11% by weight of the total weight of the second thermoplastic polyimide layer (3), for example, 2% by weight, 3% by weight, 4% by weight, 5% by weight, 6% by weight, 7% by weight, 8% by weight, 9% by weight, 10% by weight, or 11% by weight.

[0049] The toughening agent having -COOH, -NH, or -C=O polar groups may include, for example, a modified acrylate polymer. Based on the total weight of the second thermoplastic polyimide layer (3), the toughening agent having -COOH, -NH, or -C=O polar groups may comprise 7 to 16% by weight, for example, 7% by weight, 8% by weight, 9% by weight, 10% by weight, 11% by weight, 12% by weight, 13% by weight, 14% by weight, 15% by weight, or 16% by weight.

[0050] Furthermore, regarding the weight relationship between the rare earth oxide and the toughening agent with -COOH, -NH or -C=O polar groups, the weight ratio between the former and the latter may be 1:(0.64 to 8), for example 1:0.64, 1:2, 1:3.5 or 1:8.

[0051] Similarly, to provide proper shaping of the second thermoplastic polyimide layer (3), the second thermoplastic polyimide layer (3) may further contain a hardener, which may include, for example, one or more of acetic anhydride, isoquinoline, and N,N-dimethylformamide.

[0052] Another embodiment of the present invention provides a method for preparing the above-mentioned highly thermo- and oxygen-stable polyimide composite film. Although the preparation method proposed herein utilizes co-extrusion technology, it is not intended to limit the preparation of the above-mentioned highly thermo- and oxygen-stable polyimide composite film. That is, the above-mentioned highly thermo- and oxygen-stable polyimide composite film can also be prepared by other methods not mentioned, such as coating or compounding.

[0053] like Figure 4 As shown, the preparation method includes: a providing step (S1), a co-extrusion step (S2), and imidization (S3).

[0054] First, the high thermo-oxidative stability polyimide composite film of the first embodiment will be discussed.

[0055] During the provisioning step (S1), a non-thermoplastic polyamic acid solution and a first thermoplastic polyamic acid solution are provided.

[0056] The non-thermoplastic polyamic acid solution contains rare earth oxide in addition to the non-thermoplastic polyamic acid. The non-thermoplastic polyamic acid solution is used to form the non-thermoplastic polyimide layer (1) described above, and thus the type of rare earth oxide used therein can be the same as that described above with respect to the non-thermoplastic polyimide layer (1) and will not be repeated here. In order to provide the non-thermoplastic polyimide layer (1) formed thereby with a proper shape, the non-thermoplastic polyamic acid solution can further contain a hardener, and the type of hardener used can be the same as that described above with respect to the non-thermoplastic polyimide layer (1) and will not be repeated here.

[0057] The first thermoplastic polyamic acid solution contains rare earth oxide and a toughener having a -COOH, -N-H or -C=0 polar group in addition to the thermoplastic polyamic acid. The first thermoplastic polyamic acid solution is used to form the first thermoplastic polyimide layer (2) described above, and thus the type of rare earth oxide and the type of toughener having a -COOH, -N-H or -C=0 polar group used therein can be the same as that described above with respect to the first thermoplastic polyimide layer (2) and will not be repeated here. In order to provide the first thermoplastic polyimide layer (2) formed thereby with a proper shape, the first thermoplastic polyamic acid solution can further contain a hardener, and the type of hardener used can be the same as that described above with respect to the first thermoplastic polyimide layer (2) and will not be repeated here. In the first thermoplastic polyamic acid solution, the weight ratio between the rare earth oxide and the toughener having a -COOH, -N-H or -C=0 polar group can be 1:(0.64 to 8), such as 1:0.64, 1:2, 1:3.5, or 1:8.

[0058] In the co-extrusion step (S2), the non-thermoplastic polyamic acid solution and the first thermoplastic polyamic acid solution are co-extruded to obtain a co-extruded cast sheet, which comprises a non-thermoplastic polyamic acid layer and a first thermoplastic polyamic acid layer, the non-thermoplastic polyamic acid layer being located on a first side of the first thermoplastic polyamic acid layer. As such, the non-thermoplastic polyamic acid solution and the first thermoplastic polyamic acid solution are co-extruded to form the non-thermoplastic polyamic acid layer and the first thermoplastic polyamic acid layer. Any suitable commercially available die can be used for the co-extrusion, and the process conditions used are not the technical focus of the present application and thus will not be described in detail, particularly.

[0059] When performing the imidization (S3), the co-extruded cast sheet is imidized to obtain the high-thermal-oxygen-stability polyimide composite film. The imidization can be performed by heating the co-extruded cast sheet. The heating is, for example, drying at 370±5°C for 30 seconds to 300 seconds, or drying at 350±5°C for 60 seconds to 240 seconds and at 370±5°C for 30 seconds to 240 seconds in sequence or not in sequence, or drying at 300±20°C for 60 seconds to 120 seconds, at 350±5°C for 60 seconds to 180 seconds and at 370±5°C for 30 seconds to 240 seconds in sequence or not in sequence, or drying at 250±20°C for 40 seconds to 80 seconds, at 300±20°C for 60 seconds to 90 seconds, at 350±5°C for 60 seconds to 120 seconds and at 370±5°C for 30 seconds to 180 seconds in sequence or not in sequence.

[0060] Second, the high-thermal-oxygen-stability polyimide composite film of the second embodiment is discussed.

[0061] When performing the providing step (S1), a non-thermoplastic polyamic acid solution, a first thermoplastic polyamic acid solution and a second thermoplastic polyamic acid solution are provided.

[0062] The non-thermoplastic polyamic acid solution contains, in addition to the non-thermoplastic polyamic acid, a rare earth oxide. The non-thermoplastic polyamic acid solution corresponds to the formation of the non-thermoplastic polyimide layer (1) described above, and thus the type of the rare earth oxide there can refer to the description above regarding the non-thermoplastic polyimide layer (1) and will not be repeated. In order to provide the non-thermoplastic polyimide layer (1) to be formed appropriately, the non-thermoplastic polyamic acid solution can further contain a hardener, and the type thereof can also refer to the description above regarding the non-thermoplastic polyimide layer (1) and will not be repeated.

[0063] The first thermoplastic polyamic acid solution contains, in addition to the thermoplastic polyamic acid, a rare earth oxide and a toughener having a -COOH, -N-H or -C=O polar group. The first thermoplastic polyamic acid solution corresponds to the formation of the first thermoplastic polyimide layer (2) described above, and thus the type of the rare earth oxide and the toughener having a -COOH, -N-H or -C=O polar group there can refer to the description above regarding the first thermoplastic polyimide layer (2) and will not be repeated. In order to provide the first thermoplastic polyimide layer (2) to be formed appropriately, the first thermoplastic polyamic acid solution can further contain a hardener, and the type thereof can also refer to the description above regarding the first thermoplastic polyimide layer (2) and will not be repeated. In the first thermoplastic polyamic acid solution, the weight ratio between the rare earth oxide and the toughener having a -COOH, -N-H or -C=O polar group can be 1:(0.64 to 8), for example, 1:0.64, 1:2, 1:3.5, or 1:8.

[0064] The second thermoplastic polyamide acid solution contains, in addition to the thermoplastic polyamide acid, a rare earth oxide and a toughening agent having a -COOH, -N-H or -C=0 polar group. The second thermoplastic polyamide acid solution corresponds to form the aforementioned second thermoplastic polyimide layer (3), and thus the type of the rare earth oxide and the type of the toughening agent having a -COOH, -N-H or -C=0 polar group in the second thermoplastic polyamide acid solution can refer to the description of the second thermoplastic polyimide layer (3) above, and will not be described in detail. To provide the second thermoplastic polyimide layer (3) formed correspondingly with a proper shape, the second thermoplastic polyamide acid solution can further contain a hardening agent, and the type of the hardening agent can also refer to the description of the second thermoplastic polyimide layer (3) above, and will not be described in detail. In the second thermoplastic polyamide acid solution, the weight ratio between the rare earth oxide and the toughening agent having a -COOH, -N-H or -C=0 polar group can be 1:(0.64 to 8), for example, 1:0.64, 1:2, 1:3.5, or 1:8.

[0065] In the co-extrusion step (S2), the non-thermoplastic polyamide acid solution, the first thermoplastic polyamide acid solution and the second thermoplastic polyamide acid solution are co-extruded to obtain a co-extrusion cast sheet, which includes a non-thermoplastic polyamide acid layer, a first thermoplastic polyamide acid layer and a second thermoplastic polyamide acid layer. The first thermoplastic polyamide acid layer is located on a first side of the non-thermoplastic polyamide acid layer, and the second thermoplastic polyamide acid layer is located on a second side of the non-thermoplastic polyamide acid layer, so that the non-thermoplastic polyamide acid layer is located between the first thermoplastic polyamide acid layer and the second thermoplastic polyamide acid layer. Thus, the non-thermoplastic polyamide acid solution, the first thermoplastic polyamide acid solution and the second thermoplastic polyamide acid solution correspond to extrude the non-thermoplastic polyamide acid layer, the first thermoplastic polyamide acid layer and the second thermoplastic polyamide acid layer. The co-extrusion can use any suitable commercially available die, and the process conditions used are not the technical focus of the present application, and thus will not be described in detail.

[0066] In the imidization step (S3), the co-extrusion cast sheet is subjected to imidization to obtain a high-thermal-oxygen-stability polyimide composite film. The imidization can be embodied by heating the co-extrusion cast sheet. The heating, for example, includes drying at 370±5°C for 30 seconds to 300 seconds, or includes sequentially or not sequentially drying at 350±5°C for 60 seconds to 240 seconds and at 370±5°C for 30 seconds to 240 seconds, or includes sequentially or not sequentially drying at 300±20°C for 60 seconds to 120 seconds, at 350±5°C for 60 seconds to 180 seconds and at 370±5°C for 30 seconds to 240 seconds, or includes sequentially or not sequentially drying at 250±20°C for 40 seconds to 80 seconds, at 300±20°C for 60 seconds to 90 seconds, at 350±5°C for 60 seconds to 120 seconds and at 370±5°C for 30 seconds to 180 seconds.

[0067] Next, the high-heat oxygen stability polyimide composite film of the third embodiment is discussed.

[0068] In providing the step (S1), a non-thermoplastic polyamic acid solution, a first thermoplastic polyamic acid solution and a second thermoplastic polyamic acid solution are provided.

[0069] The non-thermoplastic polyamic acid solution contains, in addition to the non-thermoplastic polyamic acid, a rare earth oxide. The non-thermoplastic polyamic acid solution is later used to form the non-thermoplastic polyimide layer (1) described above, and thus the type of the rare earth oxide used therein can be referred to the description above regarding the non-thermoplastic polyimide layer (1) and will not be repeated. To provide a proper shape of the non-thermoplastic polyimide layer (1) to be formed, the non-thermoplastic polyamic acid solution can further contain a hardener, and the type of the hardener can also be referred to the description above regarding the non-thermoplastic polyimide layer (1) and will not be repeated.

[0070] The first thermoplastic polyamic acid solution contains, in addition to the thermoplastic polyamic acid, a rare earth oxide and a toughener having a -COOH, -N-H or -C=O polar group. The first thermoplastic polyamic acid solution is later used to form the first thermoplastic polyimide layer (2) described above, and thus the type of the rare earth oxide and the toughener having a -COOH, -N-H or -C=O polar group used therein can be referred to the description above regarding the first thermoplastic polyimide layer (2) and will not be repeated. To provide a proper shape of the first thermoplastic polyimide layer (2) to be formed, the first thermoplastic polyamic acid solution can further contain a hardener, and the type of the hardener can also be referred to the description above regarding the first thermoplastic polyimide layer (2) and will not be repeated. In the first thermoplastic polyamic acid solution, the weight ratio between the rare earth oxide and the toughener having a -COOH, -N-H or -C=O polar group can be 1:(0.64 to 8), such as 1:0.64, 1:2, 1:3.5, or 1:8.

[0071] The second thermoplastic polyamide acid solution contains, in addition to the thermoplastic polyamide acid, a rare earth oxide and a toughening agent having a -COOH, -N-H or -C=0 polar group. The second thermoplastic polyamide acid solution corresponds to form the aforementioned second thermoplastic polyimide layer (3), and thus the type of the rare earth oxide and the type of the toughening agent having a -COOH, -N-H or -C=0 polar group in the second thermoplastic polyamide acid solution can refer to the description of the second thermoplastic polyimide layer (3) above, and will not be repeated. To provide the second thermoplastic polyimide layer (3) formed correspondingly with a proper shape, the second thermoplastic polyamide acid solution can further contain a hardening agent, and the type of the hardening agent can also refer to the description of the second thermoplastic polyimide layer (3) above, and will not be repeated. In the second thermoplastic polyamide acid solution, the weight ratio between the rare earth oxide and the toughening agent having a -COOH, -N-H or -C=0 polar group can be 1:(0.64 to 8), for example, 1:0.64, 1:2, 1:3.5, or 1:8.

[0072] In the co-extrusion step (S2), the non-thermoplastic polyamide acid solution, the first thermoplastic polyamide acid solution and the second thermoplastic polyamide acid solution are co-extruded to obtain a co-extrusion cast sheet, which includes a non-thermoplastic polyamide acid layer, a first thermoplastic polyamide acid layer and a second thermoplastic polyamide acid layer. The first thermoplastic polyamide acid layer is located on a first side of the non-thermoplastic polyamide acid layer, and the second thermoplastic polyamide acid layer is located on the first side of the non-thermoplastic polyamide acid layer, so that the first thermoplastic polyamide acid layer is located between the non-thermoplastic polyamide acid layer and the second thermoplastic polyamide acid layer. Thus, the non-thermoplastic polyamide acid solution, the first thermoplastic polyamide acid solution and the second thermoplastic polyamide acid solution correspond to extrude the non-thermoplastic polyamide acid layer, the first thermoplastic polyamide acid layer and the second thermoplastic polyamide acid layer. The co-extrusion can use any suitable commercially available die, and the process conditions used are not the technical focus of the present application, and thus will not be described in detail.

[0073] In the imidization step (S3), the co-extrusion cast sheet is subjected to imidization to obtain a high-thermal-oxygen-stability polyimide composite film. The imidization can be embodied by heating the co-extrusion cast sheet. The heating, for example, includes drying at 370±5°C for 30 seconds to 300 seconds, or includes sequentially or not sequentially drying at 350±5°C for 60 seconds to 240 seconds and at 370±5°C for 30 seconds to 240 seconds, or includes sequentially or not sequentially drying at 300±20°C for 60 seconds to 120 seconds, at 350±5°C for 60 seconds to 180 seconds and at 370±5°C for 30 seconds to 240 seconds, or includes sequentially or not sequentially drying at 250±20°C for 40 seconds to 80 seconds, at 300±20°C for 60 seconds to 90 seconds, at 350±5°C for 60 seconds to 120 seconds and at 370±5°C for 30 seconds to 180 seconds.

[0074] The present application is illustrated by the following examples:

[0075] Synthesis Example 1: Preparation of non-thermoplastic polyamic acid solution

[0076] 0.140 mol of 2,2'-bis[4-(4-aminophenyloxy)phenyl]propane (BAPP) and 0.093 mol of 4,4'-diaminodiphenyl ether were dissolved in N,N-dimethylformamide cooled to 10°C. After dissolution, 0.093 mol of 3,3',4,4'-benzophenonetetracarboxylic dianhydride and 0.116 mol of pyromellitic dianhydride were added, and stirred for 30 minutes to obtain a prepolymer.

[0077] After adding 0.232 mol of p-phenylenediamine to the prepolymer, 0.213 mol of pyromellitic dianhydride was added, and then a separately prepared 5 wt% N,N-dimethylformamide solution of pyromellitic dianhydride was slowly added, and the addition was stopped when the viscosity reached about 250,000 cps. After stirring for 1 hour, a polyamic acid solution having a rotational viscosity of 250,000 cps at 23°C was obtained.

[0078] A hardening agent containing acetic anhydride, isoquinoline, and N,N-dimethylformamide was added to the polyamic acid solution, and stirring and defoaming were performed at a temperature of 0°C or less to obtain a non-thermoplastic polyamic acid solution.

[0079] Synthesis Example 2: Preparation of non-thermoplastic polyamic acid solution

[0080] 0.140 mol of 2,2'-bis[4-(4-aminophenyloxy)phenyl]propane (BAPP) and 0.093 mol of 4,4'-diaminodiphenyl ether were dissolved in N,N-dimethylformamide cooled to 10°C. After the dissolution, 0.093 mol of 3,3',4,4'-benzophenonetetracarboxylic dianhydride and 0.116 mol of pyromellitic dianhydride were added, and stirred uniformly for 30 minutes to obtain a prepolymer.

[0081] After 0.232 mol of p-phenylenediamine was added to the prepolymer, 0.213 mol of pyromellitic dianhydride was further added, and then a separately prepared 5 wt% N,N-dimethylformamide solution of pyromellitic dianhydride was slowly added, and the addition was stopped when the viscosity reached about 250,000 cps. After stirring for 1 hour, a polyamic acid solution having a rotary viscosity of 250,000 cps at 23°C was obtained.

[0082] A hardening agent including acetic anhydride, isoquinoline, N,N-dimethylformamide, and neodymium oxide were added to the polyamic acid solution, and stirring and defoaming were performed at a temperature of 0°C or less to obtain a non-thermoplastic polyamic acid solution containing neodymium oxide.

[0083] Synthesis Example 3: Preparation of a thermoplastic polyamic acid solution

[0084] 0.289 mol of 2,2'-bis[4-(4-aminophenyloxy)phenyl]propane was dissolved in N,N-dimethylformamide. Thereafter, 0.230 mol of 3,3',4,4'-biphenyl tetracarboxylic diandhydride was added, heated to 50°C, and then cooled to 10°C, and 0.045 mol of 3,3',4,4'-benzophenonetetracarboxylic dianhydride was added to obtain a prepolymer.

[0085] Thereafter, a separately prepared 5 wt% N,N-dimethylformamide solution of 3,3',4,4'-benzophenonetetracarboxylic dianhydride was slowly added to obtain a polyamic acid solution having a solid content of 17 wt% and a viscosity of about 250,000 cps at 23°C. Thereafter, N,N-dimethylformamide was added to obtain a polyamic acid solution having a solid content concentration of 14 wt%.

[0086] The hardener comprising acetic anhydride, isoquinoline, N,N-dimethylformamide was added to the polyamic acid solution, and stirring and defoaming were performed at a temperature of 0°C or less to obtain a thermoplastic polyamic acid solution.

[0087] Synthesis Example 4: Preparation of a thermoplastic polyamic acid solution

[0088] 0.289 mol of 2,2-bis[4-(4-aminophenoxy)phenyl]propane was dissolved in N,N-dimethylformamide. Thereafter, 0.230 mol of 3,3',4,4'-biphenyl tetracarboxylic diandhydride was added, and after heating to 50°C, the temperature was cooled to 10°C, and 0.045 mol of 3,3',4,4'-benzophenonetetracarboxylic diandhydride was added to obtain a prepolymer.

[0089] Thereafter, the prepared 5 wt% 3,3',4,4'-benzophenonetetracarboxylic diandhydride N,N-dimethylformamide solution was slowly added to obtain a polyamic acid solution having a solid content of 17 wt% and a viscosity of about 250,000 cps at 23°C. Thereafter, N,N-dimethylformamide was added to obtain a polyamic acid solution having a solid content of 14 wt%.

[0090] The hardener comprising acetic anhydride, isoquinoline, N,N-dimethylformamide and neodymium oxide was added to the polyamic acid solution, and stirring and defoaming were performed at a temperature of 0°C or less to obtain a thermoplastic polyamic acid solution containing neodymium oxide.

[0091] Synthesis Example 5: Preparation of a thermoplastic polyamic acid solution

[0092] 0.289 mol of 2,2-bis[4-(4-aminophenoxy)phenyl]propane was dissolved in N,N-dimethylformamide. Thereafter, 0.230 mol of 3,3',4,4'-biphenyl tetracarboxylic diandhydride was added, and after heating to 50°C, the temperature was cooled to 10°C, and 0.045 mol of 3,3',4,4'-benzophenonetetracarboxylic diandhydride was added to obtain a prepolymer.

[0093] Thereafter, the prepared 5 wt% 3,3',4,4'-benzophenonetetracarboxylic diandhydride N,N-dimethylformamide solution was slowly added to obtain a polyamic acid solution having a solid content of 17 wt% and a viscosity of about 250,000 cps at 23°C. Thereafter, N,N-dimethylformamide was added to obtain a polyamic acid solution having a solid content of 14 wt%.

[0094] To the polyamic acid solution, a hardening agent comprising acetic anhydride, isoquinoline, N,N-dimethylformamide, and a modified acrylate polymer were added, and stirring and defoaming were performed at a temperature of 0°C or lower to obtain a thermoplastic polyamic acid solution containing the modified acrylate polymer.

[0095] Synthesis Example 6: Preparation of a thermoplastic polyamic acid solution

[0096] 0.289 mol of 2,2-bis[4-(4-aminophenoxy)phenyl]propane was dissolved in N,N-dimethylformamide. Thereafter, 0.230 mol of 3,3',4,4'-biphenyl tetracarboxylic diandhydride was added, and after heating to 50°C, it was cooled to 10°C, and 0.045 mol of 3,3',4,4'-benzophenonetetracarboxylic diandhydride was added to obtain a prepolymer.

[0097] Thereafter, a prepared 5 wt% N,N-dimethylformamide solution of 3,3',4,4'-benzophenonetetracarboxylic diandhydride was slowly added to obtain a polyamic acid solution having a solid content of 17 wt% and a viscosity of about 250,000 cps at 23°C. Thereafter, N,N-dimethylformamide was added to obtain a polyamic acid solution having a solid content concentration of 14 wt%.

[0098] To the polyamic acid solution, a hardening agent comprising acetic anhydride, isoquinoline, N,N-dimethylformamide, and a modified acrylate polymer were added, and stirring and defoaming were performed at a temperature of 0°C or lower to obtain a thermoplastic polyamic acid solution containing the modified acrylate polymer.

[0099] To the thermoplastic polyamic acid solution containing the modified acrylate polymer, neodymium oxide was added, and stirring and defoaming were continued to obtain a thermoplastic polyamic acid solution containing neodymium oxide and the modified acrylate polymer.

[0100] Example 1

[0101] A three-layer co-extrusion multi-layer die of a multi-channel type was used, and the solutions were extrusion-cast on a support body in the order of the thermoplastic polyamide acid solution obtained in Synthesis Example 6, the non-thermoplastic polyamide acid solution obtained in Synthesis Example 2, and the thermoplastic polyamide acid solution obtained in Synthesis Example 6 by a three-layer extrusion method. Next, the three-layer film was heated at 150°C for 100 seconds, and then the three-layer gel film having self-supportability was peeled off, and the three-layer gel film was fixed to a metal frame, and then imidization was performed by drying at 250°C for 40 seconds, at 300°C for 60 seconds, at 350°C for 60 seconds, and at 370°C for 30 seconds in this order, whereby a three-layer polyimide film of a thermoplastic polyimide layer having a modified acrylate polymer content of 16 wt% and a neodymium oxide content of 2 wt% / a non-thermoplastic polyimide layer having a neodymium oxide content of 2 wt% / a thermoplastic polyimide layer having a modified acrylate polymer content of 16 wt% and a neodymium oxide content of 2 wt% was obtained.

[0102] Example 2

[0103] A three-layer co-extrusion multi-layer die of a multi-channel type was used, and the solutions were extrusion-cast on a support body in the order of the thermoplastic polyamide acid solution obtained in Synthesis Example 6, the non-thermoplastic polyamide acid solution obtained in Synthesis Example 2, and the thermoplastic polyamide acid solution obtained in Synthesis Example 6 by a three-layer extrusion method. Next, the three-layer film was heated at 150°C for 100 seconds, and then the three-layer gel film having self-supportability was peeled off, and the three-layer gel film was fixed to a metal frame, and then imidization was performed by drying at 250°C for 40 seconds, at 300°C for 60 seconds, at 350°C for 60 seconds, and at 370°C for 30 seconds in this order, whereby a three-layer polyimide film of a thermoplastic polyimide layer having a modified acrylate polymer content of 14 wt% and a neodymium oxide content of 4 wt% / a non-thermoplastic polyimide layer having a neodymium oxide content of 4 wt% / a thermoplastic polyimide layer having a modified acrylate polymer content of 14 wt% and a neodymium oxide content of 4 wt% was obtained.

[0104] Example 3

[0105] A three-layer polyimide film was obtained in the same manner as in Synthesis Example 1, except that the order of the thermoplastic polyamide acid solution obtained in Synthesis Example 6, the non-thermoplastic polyamide acid solution obtained in Synthesis Example 2, and the thermoplastic polyamide acid solution obtained in Synthesis Example 6 was used in the three-layer co-extrusion multilayer die.

[0106] Example 4

[0107] A three-layer polyimide film was obtained in the same manner as in Synthesis Example 1, except that the order of the thermoplastic polyamide acid solution obtained in Synthesis Example 6, the non-thermoplastic polyamide acid solution obtained in Synthesis Example 2, and the thermoplastic polyamide acid solution obtained in Synthesis Example 6 was used in the three-layer co-extrusion multilayer die.

[0108] Comparative Example 1

[0109] A three-layer polyimide film was obtained in the same manner as in Synthesis Example 1, except that the order of the thermoplastic polyamide acid solution obtained in Synthesis Example 6, the non-thermoplastic polyamide acid solution obtained in Synthesis Example 2, and the thermoplastic polyamide acid solution obtained in Synthesis Example 6 was used in the three-layer co-extrusion multilayer die.

[0110] Comparative Example 2

[0111] Using a multi-channel three-layer co-extrusion multi-layer die, the solutions were extrusion cast on a support body in the order of the thermoplastic polyamide acid solution obtained in Synthesis Example 4, the non-thermoplastic polyamide acid solution obtained in Synthesis Example 2, and the thermoplastic polyamide acid solution obtained in Synthesis Example 4 by a three-layer extrusion method. Next, the three-layer film was heated at 150°C for 100 seconds, and then the three-layer gel film having self-supportability was peeled off and fixed to a metal frame, and then imidization was performed by sequentially drying at 250°C for 40 seconds, at 300°C for 60 seconds, at 350°C for 60 seconds, and at 370°C for 30 seconds, thereby obtaining a three-layer polyimide film of a thermoplastic polyimide layer having a neodymium oxide content of 4 wt%, a non-thermoplastic polyimide layer having a neodymium oxide content of 4 wt%, and a thermoplastic polyimide layer having a neodymium oxide content of 4 wt%.

[0112] Comparative Example 3

[0113] Using a multi-channel three-layer co-extrusion multi-layer die, the solutions were extrusion cast on a support body in the order of the thermoplastic polyamide acid solution obtained in Synthesis Example 5, the non-thermoplastic polyamide acid solution obtained in Synthesis Example 1, and the thermoplastic polyamide acid solution obtained in Synthesis Example 5 by a three-layer extrusion method. Next, the three-layer film was heated at 150°C for 100 seconds, and then the three-layer gel film having self-supportability was peeled off and fixed to a metal frame, and then imidization was performed by sequentially drying at 250°C for 40 seconds, at 300°C for 60 seconds, at 350°C for 60 seconds, and at 370°C for 30 seconds, thereby obtaining a three-layer polyimide film of a thermoplastic polyimide layer having a modified acrylate polymer content of 16 wt%, a non-thermoplastic polyimide layer, and a thermoplastic polyimide layer having a modified acrylate polymer content of 16 wt%.

[0114] Comparative Example 4

[0115] A three-layer co-extrusion multi-layer mold of a multi-channel type was used, and the solutions were extrusion-cast on a support body in the order of the thermoplastic polyamide acid solution obtained in the aforementioned Synthesis Example 5, the non-thermoplastic polyamide acid solution obtained in Synthesis Example 1, and the thermoplastic polyamide acid solution obtained in Synthesis Example 5 by a three-layer extrusion method. Next, the three-layer film was heated at 150°C for 100 seconds, and then the three-layer gel film having self-supportability was peeled off, and the three-layer gel film was fixed to a metal frame, and then imidization was performed by sequentially drying at 250°C for 40 seconds, at 300°C for 60 seconds, at 350°C for 60 seconds, and at 370°C for 30 seconds, thereby obtaining a three-layer polyimide film of a thermoplastic polyimide layer having a modified acrylate polymer content of 14 wt% / a non-thermoplastic polyimide layer / a thermoplastic polyimide layer having a modified acrylate polymer content of 14 wt%.

[0116] Comparative Example 5

[0117] A three-layer co-extrusion multi-layer mold of a multi-channel type was used, and the solutions were extrusion-cast on a support body in the order of the thermoplastic polyamide acid solution obtained in the aforementioned Synthesis Example 4, the non-thermoplastic polyamide acid solution obtained in Synthesis Example 2, and the thermoplastic polyamide acid solution obtained in Synthesis Example 4 by a three-layer extrusion method. Next, the three-layer film was heated at 150°C for 100 seconds, and then the three-layer gel film having self-supportability was peeled off, and the three-layer gel film was fixed to a metal frame, and then imidization was performed by sequentially drying at 250°C for 40 seconds, at 300°C for 60 seconds, at 350°C for 60 seconds, and at 370°C for 30 seconds, thereby obtaining a three-layer polyimide film of a thermoplastic polyimide layer having a neodymium oxide content of 2 wt% / a non-thermoplastic polyimide layer having a neodymium oxide content of 2 wt% / a thermoplastic polyimide layer having a neodymium oxide content of 2 wt%.

[0118] Comparative Example 6

[0119] A three-layer co-extrusion multi-layer mold of a multi-channel type was used, and the solutions were extrusion-cast on a support body in the order of the thermoplastic polyamide acid solution obtained in the aforementioned Synthesis Example 4, the non-thermoplastic polyamide acid solution obtained in Synthesis Example 2, and the thermoplastic polyamide acid solution obtained in Synthesis Example 4 by a three-layer extrusion method. Next, the three-layer film was heated at 150°C for 100 seconds, and then the three-layer gel film having self-supportability was peeled off, and the three-layer gel film was fixed to a metal frame, and then imidization was performed by sequentially drying at 250°C for 40 seconds, at 300°C for 60 seconds, at 350°C for 60 seconds, and at 370°C for 30 seconds, thereby obtaining a three-layer polyimide film of a thermoplastic polyimide layer having a neodymium oxide content of 6 wt% / a non-thermoplastic polyimide layer having a neodymium oxide content of 6 wt% / a thermoplastic polyimide layer having a neodymium oxide content of 6 wt%.

[0120] Comparative Example 7

[0121] Using a multi-channel three-layer co-extrusion multi-layer die, the solutions were extrusion cast on a support body in the order of the thermoplastic polyamide acid solution obtained in Synthesis Example 5, the non-thermoplastic polyamide acid solution obtained in Synthesis Example 1, and the thermoplastic polyamide acid solution obtained in Synthesis Example 5 by a three-layer extrusion method. Next, the three-layer film was heated at 150°C for 100 seconds, and then the three-layer gel film having self-supportability was peeled off and fixed to a metal frame, and then imidization was performed by sequentially drying at 250°C for 40 seconds, at 300°C for 60 seconds, at 350°C for 60 seconds, and at 370°C for 30 seconds, thereby obtaining a three-layer polyimide film of a thermoplastic polyimide layer having a modified acrylate polymer content of 12 wt% / a non-thermoplastic polyimide layer / a thermoplastic polyimide layer having a modified acrylate polymer content of 12 wt%.

[0122] Comparative Example 8

[0123] Using a multi-channel three-layer co-extrusion multi-layer die, the solutions were extrusion cast on a support body in the order of the thermoplastic polyamide acid solution obtained in Synthesis Example 4, the non-thermoplastic polyamide acid solution obtained in Synthesis Example 2, and the thermoplastic polyamide acid solution obtained in Synthesis Example 4 by a three-layer extrusion method. Next, the three-layer film was heated at 150°C for 100 seconds, and then the three-layer gel film having self-supportability was peeled off and fixed to a metal frame, and then imidization was performed by sequentially drying at 250°C for 40 seconds, at 300°C for 60 seconds, at 350°C for 60 seconds, and at 370°C for 30 seconds, thereby obtaining a three-layer polyimide film of a thermoplastic polyimide layer having a neodymium oxide content of 11 wt% / a non-thermoplastic polyimide layer having a neodymium oxide content of 11 wt% / a thermoplastic polyimide layer having a neodymium oxide content of 11 wt%.

[0124] Comparative Example 9

[0125] Using a multi-channel three-layer co-extrusion multi-layer die, the solutions were extrusion cast on a support body in the order of the thermoplastic polyamide acid solution obtained in Synthesis Example 5, the non-thermoplastic polyamide acid solution obtained in Synthesis Example 1, and the thermoplastic polyamide acid solution obtained in Synthesis Example 5 by a three-layer extrusion method. Next, the three-layer film was heated at 150°C for 100 seconds, and then the three-layer gel film having self-supportability was peeled off and fixed to a metal frame, and then imidization was performed by sequentially drying at 250°C for 40 seconds, at 300°C for 60 seconds, at 350°C for 60 seconds, and at 370°C for 30 seconds, thereby obtaining a three-layer polyimide film of a thermoplastic polyimide layer having a modified acrylate polymer content of 7 wt% / a non-thermoplastic polyimide layer / a thermoplastic polyimide layer having a modified acrylate polymer content of 7 wt%.

[0126] Referring to Table 1, the Tg, tensile modulus, tensile strength, elongation at break, and thermal stability of the polyimide films of Examples 1 to 4 were all higher than those of Comparative Example 1, indicating that the addition of neodymium oxide and modified acrylate polymer to the thermoplastic polyimide layer and the addition of neodymium oxide to the non-thermoplastic polyimide layer can improve the high-temperature oxygen stability of the polyimide film. d 5% were all higher than those of Comparative Example 1, indicating that the addition of neodymium oxide and modified acrylate polymer to the thermoplastic polyimide layer and the addition of neodymium oxide to the non-thermoplastic polyimide layer can improve the high-temperature oxygen stability of the polyimide film.

[0127] Referring to Table 1, the tensile modulus, tensile strength, elongation at break, Tg, and thermal stability of the polyimide film of Example 1 were all higher than those of Comparative Example 2, indicating that the addition of neodymium oxide and modified acrylate polymer to the thermoplastic polyimide layer can improve the mechanical strength and high-temperature oxygen stability of the polyimide film. d 5% were all higher than those of Comparative Example 3 and 5, indicating that the tensile modulus, tensile strength, Tg, and thermal stability of the polyimide film of Example 2 were all higher than those of Comparative Example 3 and 5. d 5% were all higher than those of Comparative Example 2 and 4, indicating that the addition of neodymium oxide and modified acrylate polymer to the thermoplastic polyimide layer can improve the mechanical strength and high-temperature oxygen stability of the polyimide film.

[0128] Table 1, Test results of polyimide films

[0129]

[0130]

[0131] The above description relating to common knowledge is not described in detail, and those skilled in the art can understand it.

[0132] The above description is only some specific embodiments of the present application and does not limit the present application. Any modification, equivalent replacement, improvement, etc. made within the spirit and principles of the present application shall be included in the protection scope of the present application. The technical scope of the present application is not limited to the content in the specification, and must be determined according to the scope of claims.

Claims

1. A polyimide composite film having high thermal and oxidative stability, characterized by comprising: Comprising: a non-thermoplastic polyimide layer and a first thermoplastic polyimide layer, the first thermoplastic polyimide layer being on a first side of the non-thermoplastic polyimide layer; the non-thermoplastic polyimide layer contains rare earth oxides, the rare earth oxides in the non-thermoplastic polyimide layer comprising one or more of lanthanum oxide, cerium oxide, praseodymium oxide, neodymium oxide, promethium oxide, samarium oxide, europium oxide, gadolinium oxide, terbium oxide, dysprosium oxide, holmium oxide, erbium oxide, thulium oxide, ytterbium oxide, lutetium oxide, yttrium oxide, scandium oxide; the first thermoplastic polyimide layer contains rare earth oxides and toughening agents with -COOH, -N-H or -C=O polar groups, the toughening agents in the first thermoplastic polyimide layer comprising modified acrylate polymers; the rare earth oxides in the first thermoplastic polyimide layer account for 2 to 4% by weight based on the total weight of the first thermoplastic polyimide layer, and the toughening agents in the first thermoplastic polyimide layer account for 14 to 16% by weight.

2. The high-thermo-oxidative stability polyimide composite film according to claim 1, characterized in that, Further comprising: a second thermoplastic polyimide layer, the second thermoplastic polyimide layer containing rare earth oxides and toughening agents with -COOH, -N-H or -C=O polar groups; wherein the second thermoplastic polyimide layer is on a second side of the non-thermoplastic polyimide layer, such that the non-thermoplastic polyimide layer is between the first thermoplastic polyimide layer and the second thermoplastic polyimide layer, or the second thermoplastic polyimide layer is on the first side of the non-thermoplastic polyimide layer, such that the first thermoplastic polyimide layer is between the non-thermoplastic polyimide layer and the second thermoplastic polyimide layer.

3. The high thermal-oxygen stability polyimide composite film according to claim 2, wherein: the rare earth oxides in the first thermoplastic polyimide layer comprise one or more of lanthanum oxide, cerium oxide, praseodymium oxide, neodymium oxide, promethium oxide, samarium oxide, europium oxide, gadolinium oxide, terbium oxide, dysprosium oxide, holmium oxide, erbium oxide, thulium oxide, ytterbium oxide, lutetium oxide, yttrium oxide, scandium oxide; the rare earth oxides in the second thermoplastic polyimide layer comprise one or more of lanthanum oxide, cerium oxide, praseodymium oxide, neodymium oxide, promethium oxide, samarium oxide, europium oxide, gadolinium oxide, terbium oxide, dysprosium oxide, holmium oxide, erbium oxide, thulium oxide, ytterbium oxide, lutetium oxide, yttrium oxide, scandium oxide; and / or, the toughening agents in the second thermoplastic polyimide layer comprise modified acrylate polymers.

4. The high thermal-oxygen stability polyimide composite film according to claim 2, wherein: the rare earth oxides in the non-thermoplastic polyimide layer account for 2 to 11% by weight based on the total weight of the non-thermoplastic polyimide layer; the rare earth oxides in the second thermoplastic polyimide layer account for 2 to 11% by weight based on the total weight of the second thermoplastic polyimide layer; and / or, the toughening agents in the second thermoplastic polyimide layer account for 7 to 16% by weight based on the total weight of the second thermoplastic polyimide layer.

5. The high thermal-oxygen stability polyimide composite film according to claim 2, wherein: a weight ratio between the rare earth oxide in the first thermoplastic polyimide layer and the toughening agent in the first thermoplastic polyimide layer is 1:(3.5 to 8); and / or, a weight ratio between the rare earth oxide in the second thermoplastic polyimide layer and the toughening agent in the second thermoplastic polyimide layer is 1:(0.64 to 8).

6. The high-thermo-oxidative stability polyimide composite film according to claim 1, characterized in that, The 5% thermal decomposition temperature (T d 5) of the high-thermo-oxidative stability polyimide composite film is 480 to 537℃.

7. A method for preparing a polyimide composite film with high thermo-oxidative stability, characterized in that, Comprising: providing a non-thermoplastic polyamic acid solution containing a rare earth oxide and a first thermoplastic polyamic acid solution containing a rare earth oxide and a toughening agent with -COOH, -N-H or -C=O polar group, a weight ratio between the rare earth oxide in the first thermoplastic polyamic acid solution and the toughening agent in the first thermoplastic polyamic acid solution is 1:(3.5 to 8), the rare earth oxide in the non-thermoplastic polyamic acid solution comprises one or more of lanthanum oxide, cerium oxide, praseodymium oxide, neodymium oxide, promethium oxide, samarium oxide, europium oxide, gadolinium oxide, terbium oxide, dysprosium oxide, holmium oxide, erbium oxide, thulium oxide, ytterbium oxide, lutetium oxide, yttrium oxide, scandium oxide, and the toughening agent in the first thermoplastic polyamic acid solution comprises a modified acrylate polymer; co-extruding the non-thermoplastic polyamic acid solution and the first thermoplastic polyamic acid solution to obtain a co-extrusion cast sheet, the co-extrusion cast sheet comprising a non-thermoplastic polyamic acid layer and a first thermoplastic polyamic acid layer, the first thermoplastic polyamic acid layer being located on a first side of the non-thermoplastic polyamic acid layer; and and imidizing the co-extrusion cast sheet to obtain the high-thermal-oxygen-stability polyimide composite film.

8. The method for preparing a high-thermal-oxygen-stability polyimide composite film according to claim 7, wherein the rare earth oxide in the first thermoplastic polyamic acid solution comprises one or more of lanthanum oxide, cerium oxide, praseodymium oxide, neodymium oxide, promethium oxide, samarium oxide, europium oxide, gadolinium oxide, terbium oxide, dysprosium oxide, holmium oxide, erbium oxide, thulium oxide, ytterbium oxide, lutetium oxide, yttrium oxide, scandium oxide.

9. The method for preparing a high-thermal-oxygen-stability polyimide composite film according to claim 7, wherein the non-thermoplastic polyamic acid solution further comprises a hardening agent; and / or the first thermoplastic polyamic acid solution further comprises a hardening agent.

10. The method for preparing a high-thermal-oxygen-stability polyimide composite film according to claim 9, wherein the hardening agent in the non-thermoplastic polyamic acid solution comprises one or more of acetic anhydride, isoquinoline, N,N-dimethylformamide; and / or the hardening agent in the first thermoplastic polyamic acid solution comprises one or more of acetic anhydride, isoquinoline, N,N-dimethylformamide.

11. The method for preparing a high thermo-oxidative stable polyimide composite film according to claim 7, characterized in that, the imidizing comprises heating the co-extrusion cast sheet.

12. A method for preparing a polyimide composite film with high thermo-oxidative stability, characterized in that, Comprising: A non-thermoplastic polyamide acid solution, a first thermoplastic polyamide acid solution and a second thermoplastic polyamide acid solution are provided, the non-thermoplastic polyamide acid solution contains rare earth oxide, the first thermoplastic polyamide acid solution contains rare earth oxide and toughening agent with -COOH, -N-H or -C=O polar group, the weight ratio between the rare earth oxide in the first thermoplastic polyamide acid solution and the toughening agent in the first thermoplastic polyamide acid solution is 1:(3.5 to 8), the second thermoplastic polyamide acid solution contains rare earth oxide and toughening agent with -COOH, -N-H or -C=O polar group, the rare earth oxide in the non-thermoplastic polyamide acid solution comprises one or more of lanthanum oxide, cerium oxide, praseodymium oxide, neodymium oxide, promethium oxide, samarium oxide, europium oxide, gadolinium oxide, terbium oxide, dysprosium oxide, holmium oxide, erbium oxide, thulium oxide, ytterbium oxide, lutetium oxide, yttrium oxide, scandium oxide, the toughening agent in the first thermoplastic polyamide acid solution comprises modified acrylate polymer; The non-thermoplastic polyamide acid solution, the first thermoplastic polyamide acid solution and the second thermoplastic polyamide acid solution are co-extruded to obtain a co-extrusion cast sheet, the co-extrusion cast sheet comprises a non-thermoplastic polyamide acid layer, a first thermoplastic polyamide acid layer and a second thermoplastic polyamide acid layer; wherein the first thermoplastic polyamide acid layer is located on a first side of the non-thermoplastic polyamide acid layer; the second thermoplastic polyamide acid layer is located on a second side of the non-thermoplastic polyamide acid layer, so that the non-thermoplastic polyamide acid layer is located between the first thermoplastic polyamide acid layer and the second thermoplastic polyamide acid layer, or the second thermoplastic polyamide acid layer is located on the first side of the non-thermoplastic polyamide acid layer, so that the first thermoplastic polyamide acid layer is located between the non-thermoplastic polyamide acid layer and the second thermoplastic polyamide acid layer; and The co-extrusion cast sheet is imidized to obtain the high-thermal-oxygen-stability polyimide composite film.

13. The method for preparing the high-thermal-oxygen-stability polyimide composite film according to claim 12, wherein the rare earth oxide in the first thermoplastic polyamide acid solution comprises one or more of lanthanum oxide, cerium oxide, praseodymium oxide, neodymium oxide, promethium oxide, samarium oxide, europium oxide, gadolinium oxide, terbium oxide, dysprosium oxide, holmium oxide, erbium oxide, thulium oxide, ytterbium oxide, lutetium oxide, yttrium oxide, scandium oxide; the rare earth oxide in the second thermoplastic polyamide acid solution comprises one or more of lanthanum oxide, cerium oxide, praseodymium oxide, neodymium oxide, promethium oxide, samarium oxide, europium oxide, gadolinium oxide, terbium oxide, dysprosium oxide, holmium oxide, erbium oxide, thulium oxide, ytterbium oxide, lutetium oxide, yttrium oxide, scandium oxide; and / or the toughening agent in the second thermoplastic polyamide acid solution comprises modified acrylate polymer.

14. The method for preparing the high-thermal-oxygen-stability polyimide composite film according to claim 12, wherein the non-thermoplastic polyamide acid solution further comprises a hardening agent; the first thermoplastic polyamide acid solution further comprises a hardening agent; and / or the second thermoplastic polyamide acid solution further comprises a hardening agent. ​ ​ ​ ​ ​ ​ The second thermoplastic polyamide acid solution further includes a hardener. 15.The method of claim 14, wherein the high-thermo-oxidative stability polyimide composite film is prepared by the steps of: The hardener in the non-thermoplastic polyamide acid solution includes one or more of acetic anhydride, isoquinoline, and N,N-dimethylformamide. The hardener in the first thermoplastic polyamide acid solution includes one or more of acetic anhydride, isoquinoline, and N,N-dimethylformamide; and / or, The hardener in the second thermoplastic polyamide acid solution includes one or more of acetic anhydride, isoquinoline, and N,N-dimethylformamide. 16.The method of claim 12, wherein the high-thermo-oxidative stability polyimide composite film is prepared by the steps of: The weight ratio between the rare earth oxide in the second thermoplastic polyamide acid solution and the toughening agent in the second thermoplastic polyamide acid solution is 1:(0.64 to 8).

17. The method for preparing a high thermo-oxidative stable polyimide composite film according to claim 12, characterized in that, The imidization includes heating the co-extrusion cast sheet.

Images