Vacuum bag film for composite material processing forming and its preparation method and application

Abstract

The application provides a vacuum bag film for composite material processing and forming, a preparation method and application thereof, and raw materials for preparing the vacuum bag film include PFA resin and additives. The vacuum bag film is prepared by using the PFA resin as a main material, matching with related additives, melting mixing, casting film forming and cooling and shaping, and has excellent temperature resistance, sealing property and tensile property. The highest use temperature can reach 305 DEG C, and the vacuum bag film can be used for a long time at an environmental temperature of 260 DEG C, thereby meeting the processing requirements of composite material ultrahigh-temperature curing in the field of aviation and aerospace.

Description

TECHNICAL FIELD

[0001] The present application belongs to the technical field of composite material forming, and particularly relates to a vacuum bag film for composite material processing and forming, and a preparation method and application thereof. BACKGROUND

[0002] With the rapid development of aerospace technology, more and more high-performance composite materials are applied in the field of aerospace. As an essential consumable material in the production process of composite material products, the demand for vacuum auxiliary materials is gradually increasing. In the production process of composite material parts, the vacuum bag film plays a very important role. As a key auxiliary material in the composite material forming process, the quality of the vacuum bag film plays a crucial role in the manufacture of composite material parts. In the past two years, with the gradual development of the privatization of aviation technology, the demand for vacuum bags used in the forming process of composite materials with a temperature resistance of more than 260℃ has increased significantly.

[0003] At present, the commonly used vacuum bag film is a polyamide vacuum bag film. CN112874097A discloses a high-temperature and high-efficiency release Teflon and nylon multilayer composite material. The high-temperature and high-efficiency release Teflon and nylon multilayer composite material has a three-layer or five-layer structure. When the structure is three layers, the first layer is Teflon, the second layer is adhesive resin, and the third layer is PA6 or PA66. When the structure is five layers, the first layer is Teflon, the second layer is adhesive resin, the third layer is PA6 or PA66, the fourth layer is adhesive resin, and the fifth layer is Teflon. The technical solution adopts a multilayer structure combining Teflon and nylon, which can greatly improve the high-temperature resistance, tensile strength and other properties of the film. The highest temperature resistance is 220℃. However, Teflon has excellent non-stick properties, is prone to delamination, and the temperature resistance still needs to be further improved. Moreover, the temperature resistance of the multilayer composite material provided by the technical solution is still poor, which cannot meet the production requirements of modern society.

[0004] Therefore, it is still a focus in the field to develop a vacuum bag film for composite material processing and forming with excellent temperature resistance, air tightness and tensile properties. SUMMARY

[0005] In view of the deficiencies of the prior art, the purpose of the present application is to provide a vacuum bag film for composite material processing and forming, and a preparation method and application thereof. The highest use temperature of the vacuum bag film can reach 305℃, and it can be used at an environmental temperature of 260℃ for a long time. It not only meets the requirements of strength, modulus and temperature resistance of the vacuum bag film required by the super-high-temperature curing of composite materials in the field of aerospace, but also guarantees the air tightness requirement of the vacuum bag.

[0006] To achieve this purpose, the technical solution adopted by the present application is as follows:

[0007] The first aspect of the present application provides a vacuum bag film for composite material processing forming, and raw materials for preparing the vacuum bag film include PFA resin and an additive.

[0008] The raw materials for preparing the vacuum bag film provided by the present application include PFA resin and an additive, wherein the PFA resin is a tetrafluoroethylene-perfluoroalkoxy vinyl ether copolymer in Chinese, and the vacuum bag film made of the PFA resin as the main material has excellent temperature resistance, sealing performance and tensile properties, the maximum use temperature can reach 305℃, and can be used at an environmental temperature of 260℃ for a long time, meeting the forming requirements of composite material ultrahigh temperature curing in the aerospace field.

[0009] Preferably, the thickness of the vacuum bag film is 25-150μm, for example, 30μm, 50μm, 70μm, 90μm, 110μm or 130μm, and specific point values between the above point values, limited by the length and for the sake of simplicity, the present application does not exhaustively list the specific point values included in the range.

[0010] Preferably, the single-sided surface roughness of the vacuum bag film is 0.3-10μm, for example, 0.5μm, 1μm, 2μm, 3μm, 4μm, 5μm, 6μm, 7μm, 8μm or 9μm, and specific point values between the above point values, limited by the length and for the sake of simplicity, the present application does not exhaustively list the specific point values included in the range.

[0011] It should be noted that the present application only limits the roughness of the single-sided surface of the provided vacuum bag film, and the side surface with roughness can be used as the use surface, and the roughness of the other side surface is not specially limited.

[0012] As a preferred technical solution of the present application, the single-sided surface roughness of the vacuum bag film is further limited to 0.3-10μm, because the vacuum bag formed by the subsequent preparation of the vacuum bag film needs to be adhered to the sealing tape to form a vacuum environment during the composite material forming process, and since the PFA resin is a fluorine-containing material, the surface energy is low, and a certain degree of roughness is formed on the use surface, which increases the specific surface area and is more easily adhered to the sealing tape; if the single-sided surface roughness of the vacuum bag film is too large, the tensile properties of the vacuum bag film will be seriously reduced, and if the single-sided surface roughness of the vacuum bag film is too small, it will not be easy to adhere to the sealing tape during the use of the composite material forming process, and a sealed environment cannot be formed.

[0013] Preferably, the PFA resin has a melt index of 1 to 20 g / 10 min, such as 2 g / 10 min, 4 g / 10 min, 6 g / 10 min, 8 g / 10 min, 10 g / 10 min, 12 g / 10 min, 14 g / 10 min, 16 g / 10 min, or 18 g / 10 min, and specific point values between the aforementioned point values. For the sake of brevity and conciseness, the present application does not exhaustively list the specific point values included in the range, and for example, the PFA resin can be selected from the PFA resin of Daikin AP-230 or Daikin AP-231SH.

[0014] It should be noted that in the present application, the test condition of the "melt index" is 375°C / 5 kg.

[0015] Preferably, the mass percentage of the PFA resin in the raw material for preparing the vacuum bag film is 70 to 99%, such as 72%, 74%, 76%, 78%, 80%, 82%, 84%, 86%, 88%, 90%, 92%, 94%, 96%, or 98%, and specific point values between the aforementioned point values. For the sake of brevity and conciseness, the present application does not exhaustively list the specific point values included in the range.

[0016] Preferably, the auxiliary agent includes a heat stabilizer, such as KH50 of Xiamen Sanyoude Material Development Co., Ltd.

[0017] Preferably, the mass percentage of the auxiliary agent in the raw material for preparing the vacuum bag film is 1 to 30%, such as 3%, 6%, 9%, 11%, 13%, 15%, 17%, 19%, 21%, 23%, 25%, 27%, or 29%, and specific point values between the aforementioned point values. For the sake of brevity and conciseness, the present application does not exhaustively list the specific point values included in the range.

[0018] Preferably, the raw material for preparing the vacuum bag film further includes a color masterbatch.

[0019] Preferably, the color masterbatch includes a yellow color masterbatch, such as Kolan PFA Yellow Color Masterbatch 342.44.

[0020] Preferably, the mass percentage of the color masterbatch in the raw material for preparing the vacuum bag film is 1 to 20%, such as 2%, 4%, 6%, 8%, 10%, 12%, 14%, 16%, or 18%, and specific point values between the aforementioned point values. For the sake of brevity and conciseness, the present application does not exhaustively list the specific point values included in the range.

[0021] In a second aspect, the present application provides a method for preparing the vacuum bag film according to the first aspect, which comprises the following steps: melt-mixing PFA resin, additives and optionally color masterbatch, casting into film and cooling and setting to obtain the vacuum bag film.

[0022] Preferably, the temperature of the melt-mixing is 330-420℃, for example 340℃, 350℃, 360℃, 370℃, 380℃, 390℃, 400℃ or 410℃, and specific point values between the above point values. Due to the limitation of the length and for the sake of simplicity, the present application will not list the specific point values included in the range.

[0023] Preferably, the temperature of the cooling and setting is 120-180℃, for example 130℃, 140℃, 150℃, 160℃ or 170℃, and specific point values between the above point values. Due to the limitation of the length and for the sake of simplicity, the present application will not list the specific point values included in the range.

[0024] Preferably, the cooling and setting is carried out in a cooling roller, which is cooled by conducting heat oil and the temperature of the cooling roller is controlled at 120-180℃ after passing through the internal cooling and heating exchanger of the cooling roller. The rotating speed of the cooling roller should be controlled at 1-10 m / min, for example 2 m / min, 3 m / min, 4 m / min, 5 m / min, 6 m / min, 7 m / min, 8 m / min or 9 m / min, and specific point values between the above point values. Due to the limitation of the length and for the sake of simplicity, the present application will not list the specific point values included in the range.

[0025] Preferably, the cooling roller is a frosted roller, and the roughness of the frosted roller is 0.3-10, so that the film surface forms a certain roughness, which is helpful for the later use of the vacuum bag film.

[0026] As a preferred technical solution, the method for preparing the vacuum bag film specifically comprises the following steps:

[0027] (1) adding PFA resin, additives and optionally color masterbatch into an extruder, melt-mixing at 330-420℃ (for example 340℃, 350℃, 360℃, 370℃, 380℃, 390℃, 400℃ or 410℃, etc.), extruding through a casting machine T-shaped die with a lip gap of 0.02-0.07 mm (for example 0.03 mm, 0.04 mm, 0.05 mm or 0.06 mm, etc.) at 350-420℃ (for example 360℃, 370℃, 380℃, 390℃, 400℃ or 410℃, etc.), and then uniformly blowing up by a gas knife with a gas pressure of 0.2-0.7 MPa (for example 0.3 MPa, 0.4 MPa, 0.5 MPa or 0.6 MPa, etc.) to adhere to the casting cooling roller to obtain an extruded blank film;

[0028] (2) The extruded blank film obtained in step (2) is shaped by a sanded roller at a temperature of 120-180℃ (for example, 130℃, 140℃, 150℃, 160℃ or 170℃, etc.), to obtain the vacuum bag film.

[0029] In a third aspect, the present application provides a use of the vacuum bag film according to the first aspect in the molding of composite materials.

[0030] Compared with the prior art, the present application has the following beneficial effects:

[0031] (1) The raw material for preparing the vacuum bag film for the molding of composite materials provided by the present application comprises PFA resin and an additive, and the PFA resin is used as the main material, and the relevant additive is used in combination, so that the vacuum bag film prepared has excellent temperature resistance, sealing property and tensile property, the maximum use temperature can reach 305℃, and the vacuum bag film can be used for a long time at an environmental temperature of 260℃, thereby meeting the molding requirements of composite materials in the aerospace field.

[0032] (2) Specifically, the vacuum bag film provided by the present application has a tensile strength of 25-36 MPa, an elongation at break of 230-370%, and an elastic modulus of 600-670 MPa in the MD direction; a tensile strength of 24-38 MPa, an elongation at break of 240-380%, and an elastic modulus of 560-670 MPa in the TD direction; and can be used in an environment at a temperature of 260℃ and a pressure of 0.6 MPa for more than 6 hours. DETAILED DESCRIPTION

[0033] The technical solutions of the present application will be further described below through specific embodiments. Those skilled in the art should understand that the embodiments are only used to help understand the present application, and should not be regarded as a specific limitation on the present application.

[0034] Some raw material information involved in the specific embodiments of the present application is shown as follows:

[0035] PFA resin: from Daikin AP-230, with a melt index of 2.0 g / 10 min at 375℃ / 5 kg;

[0036] Heat stabilizer: KH50 from Xiamen Sanyoude Material Development Co., Ltd.;

[0037] Color masterbatch: specifically, Kolan PFA yellow masterbatch 342.44;

[0038] PA6 resin: from BASF B40L; copolymerized nylon PA6 / 66 resin: from BASF C40L.

[0039] Example 1

[0040] A vacuum bag film for composite material processing forming, the thickness is 100μm, the surface roughness is 5μm, the preparation raw material includes the following components by mass percentage:

[0041] PFA resin 90%;

[0042] Heat stabilizer 5%;

[0043] Color masterbatch 5%;

[0044] The preparation method of the vacuum bag film provided in the embodiment includes the following steps:

[0045] (1) PFA resin, heat stabilizer and color masterbatch are added into an extruder, and after melting and mixing at 400℃, they are extruded through a casting machine T-shaped die with a lip gap of 0.05mm at 400℃, and then uniformly blown up by a gas knife with a gas pressure of 0.5MPa to be attached to a casting cooling roller to obtain an extruded blank film;

[0046] (2) The extruded blank film obtained in step (2) is shaped by a frosted roller with a temperature of 150℃ to obtain the vacuum bag film; wherein the rotating speed of the frosted roller is 5m / min, and the frosted roller is cooled by passing through a cold and hot exchanger inside the frosted roller to control the temperature of the frosted roller at 150℃.

[0047] Example 2

[0048] A vacuum bag film for composite material processing forming, the thickness is 150μm, the surface roughness is 9μm, the preparation raw material includes the following components by mass percentage:

[0049] PFA resin 80%;

[0050] Heat stabilizer 10%;

[0051] Color masterbatch 10%;

[0052] The preparation method of the vacuum bag film provided in the embodiment includes the following steps:

[0053] (1) PFA resin, heat stabilizer and color masterbatch are added into an extruder, and after melting and mixing at 420℃, they are extruded through a casting machine T-shaped die with a lip gap of 0.07mm at 420℃, and then uniformly blown up by a gas knife with a gas pressure of 0.7MPa to be attached to a casting cooling roller to obtain an extruded blank film;

[0054] (2) The extruded blank film obtained in step (2) is shaped by a frosted roller with a temperature of 180℃ to obtain the vacuum bag film; wherein the rotating speed of the frosted roller is 10m / min, and the frosted roller is cooled by passing through a cold and hot exchanger inside the frosted roller to control the temperature of the frosted roller at 180℃.

[0055] Example 3

[0056] A vacuum bag film for composite material processing and forming, having a thickness of 30 μm and a surface roughness of 0.5 μm, and prepared from raw materials including the following components by mass percentage:

[0057] PFA resin 70%;

[0058] Heat stabilizer 15%;

[0059] Color masterbatch 15%;

[0060] The preparation method of the vacuum bag film provided in the embodiment includes the following steps:

[0061] (1) PFA resin, heat stabilizer and color masterbatch are added to an extruder, melted and mixed at 350°C, then extruded through a casting machine T-shaped die with a lip gap of 0.02 mm at 350°C, and then uniformly blown up by a gas knife with a gas pressure of 0.7 MPa to be attached to a casting cooling roller, to obtain an extruded blank film;

[0062] (2) The extruded blank film obtained in step (2) is shaped by a frosted roller at a temperature of 150°C to obtain the vacuum bag film; wherein the frosted roller rotates at a speed of 2 m / min, is cooled by conducting heat oil, and the temperature of the frosted roller is controlled at 150°C after passing through the internal heat exchanger of the frosted roller.

[0063] Example 4

[0064] A vacuum bag film for composite material processing and forming, which is different from Example 1 in that the surface roughness is 0.3 μm, and the other components, amounts and preparation methods are the same as those of Example 1.

[0065] Example 5

[0066] A vacuum bag film for composite material processing and forming, which is different from Example 1 in that the surface roughness is 10 μm, and the other components, amounts and preparation methods are the same as those of Example 1.

[0067] Example 6

[0068] A vacuum bag film for composite material processing and forming, which is different from Example 1 in that the surface roughness is 0.1 μm, and the other components, amounts and preparation methods are the same as those of Example 1.

[0069] Example 7

[0070] A vacuum bag film for composite material processing and forming, which is different from Example 1 in that the surface roughness is 15 μm, and the other components, amounts and preparation methods are the same as those of Example 1.

[0071] Example 8

[0072] A vacuum bag film for composite material processing and forming, which is different from example 1 in that the addition amount of PFA resin is 98%, the addition amount of heat stabilizer is 1%, the addition amount of color masterbatch is 1%, and other components, amounts and preparation methods are the same as example 1.

[0073] Example 9

[0074] A vacuum bag film for composite material processing and forming, which is different from example 1 in that the addition amount of PFA resin is 60%, the addition amount of heat stabilizer is 20%, the addition amount of color masterbatch is 20%, and other components, amounts and preparation methods are the same as example 1.

[0075] Comparative example 1

[0076] A vacuum bag film for composite material processing and forming, which is different from example 1 in that no heat stabilizer is added, the addition amount of PFA resin is 95%, and other components, amounts and preparation methods are the same as example 1.

[0077] Comparative example 2

[0078] A vacuum bag film for composite material processing and forming, which is different from example 1 in that PA6 resin is used to replace PFA resin, and other components, amounts and preparation methods are the same as example 1.

[0079] Comparative example 3

[0080] A vacuum bag film for composite material processing and forming, which is different from example 1 in that copolymerized nylon PA6 / 66 resin is used to replace PFA resin, and other components, amounts and preparation methods are the same as example 1.

[0081] Performance test:

[0082] (1) Heat resistance: the vacuum bag film is used as a vacuum auxiliary material for composite material product production, and the test is a hot-pressing vacuum tank test, the test temperature is 260℃, the pressure is 0.6MPa, the time is 6h, and the temperature resistance observation experiment is whether the vacuum degree is less than-0.7Mpa, and the smaller the vacuum degree, the better the temperature resistance;

[0083] (2) Tensile strength, elongation at break and elastic modulus: tested according to the test method provided in GB / T 1040.3-2006, wherein, "MD direction" means parallel to the mechanical stretching direction during preparation of the vacuum bag film; "TD direction" means perpendicular to the mechanical stretching direction during preparation of the vacuum bag film.

[0084] The vacuum bag films provided in examples 1-9 and comparative examples 1-3 are tested according to the above test method, and the test results are shown in table 1:

[0085] Table 1

[0086]

[0087]

[0088] According to the data in Table 1, it can be seen that the vacuum bag film provided by the application has excellent temperature resistance, sealing performance and tensile properties;

[0089] Specifically, as can be seen from Examples 1-9, the tensile strength of the vacuum bag film in the MD direction is 25-36 MPa, the elongation at break is 230-370%, and the elastic modulus is 600-670 MPa; the tensile strength in the TD direction is 24-38 MPa, the elongation at break is 240-380%, and the elastic modulus is 560-670 MPa; it can be used in an environment of 260℃, 0.6MPa for more than 6 hours;

[0090] Compared with Example 1, if the heat stabilizer is not included in the raw material (Comparative Example 1), the vacuum degree of the vacuum bag film obtained will be reduced, and the temperature resistance will be decreased;

[0091] Compared with Example 1, if the traditional nylon resin is used to replace the PFA resin (Comparative Examples 2 / 3), due to the lower melting point of the traditional nylon material, the vacuum bag film cannot be used in an environment of 260℃, 0.6MPa.

[0092] The applicant declares that the application illustrates a vacuum bag film for processing and molding of composite materials and a preparation method and application thereof through the above examples, but the application is not limited to the above examples, i.e. it does not mean that the application must rely on the above examples to be implemented. It should be understood by those skilled in the art that any improvement on the application, equivalent replacement of each raw material of the product of the application, addition of auxiliary ingredients, selection of specific methods, etc. fall within the protection scope and disclosure scope of the application.

Claims

1. A vacuum bag film for composite material processing and molding with a maximum operating temperature of 305°C, characterized in that, The raw materials for preparing the vacuum bag film include PFA resin and additives; The additives include heat stabilizers; The surface roughness of one side of the vacuum bag film is 5~9 μm; The raw materials for preparing the vacuum bag film contain 70-90% PFA resin by mass.

2. The vacuum bag film according to claim 1, characterized in that, The thickness of the vacuum bag film is 25~150 μm.

3. The vacuum bag film according to claim 1, characterized in that, The melt index of the PFA resin is 1~20 g / 10min.

4. The vacuum bag film according to claim 1, characterized in that, The mass percentage of additives in the raw materials for preparing the vacuum bag film is 1-30%.

5. The vacuum bag film according to claim 1, characterized in that, The raw materials used in the preparation of the vacuum bag film also include color masterbatch.

6. The vacuum bag film according to claim 5, characterized in that, The color masterbatch includes yellow masterbatch.

7. The vacuum bag film according to claim 5, characterized in that, The color masterbatch in the raw materials for preparing the vacuum bag film has a mass percentage content of 1-20%.

8. A method for preparing a vacuum bag film as described in any one of claims 1 to 7, characterized in that, The preparation method includes the following steps: melting and mixing PFA resin, additives and optionally color masterbatch, casting into a film and cooling to set the film, thereby obtaining the vacuum bag film.

9. The preparation method according to claim 8, characterized in that, The melting and mixing temperature is 330~420℃.

10. The preparation method according to claim 8, characterized in that, The cooling and shaping temperature is 120~180℃.

11. The preparation method according to claim 8, characterized in that, The cooling and shaping process is carried out in a cooling roller.

12. The preparation method according to claim 11, characterized in that, The cooling roller is a frosted roller.

13. The preparation method according to claim 8, characterized in that, The preparation method specifically includes the following steps: (1) PFA resin, additives and optional color masterbatch are added to the extruder and melt-mixed at 330~420℃. The mixture is then extruded at 350~420℃ through a T-die of a casting machine with a lip gap of 0.02~0.07 mm. The mixture is then blown up evenly by an air knife with an air pressure of 0.2~0.7 MPa and adhered to the casting cooling roller to obtain the extruded preform film. (2) The extruded preform film obtained in step (2) is cooled and shaped by a grinding roller with a rotation speed of 1~10 m / min and a temperature of 120~180℃ to obtain the vacuum bag film.

14. The application of a vacuum bag film as described in any one of claims 1 to 7 in composite material molding.

Images