A continuous preparation method of pre-shaped fabric with toughening function

Abstract

The present application belongs to the field of liquid forming composite material modification, and relates to a continuous preparation method of pre-shaped fabric with toughening function. First, the carbon fiber fabric is subjected to high-temperature desizing through a high-temperature drying channel; then, the setting agent is spread on the surface of the carbon fiber fabric through a first powder spreading device, and the toughening film is unfolded onto the carbon fiber fabric, and the carbon fiber fabric and the toughening film are pressed through a rolling roller; then, the setting agent is melted through a first medium-temperature drying channel, and then the setting agent is spread on the surface of the toughening film through a powder spreading device, and the setting agent on the surface of the toughening film is melted again through a medium-temperature drying channel, and is adhered to the surface of the toughening film; finally, the pre-shaped fabric with the toughening film is wound into a roll. The present application realizes the continuous preparation of the pre-shaped fabric with the toughening function, and further significantly improves the interlayer toughness and impact damage resistance of the liquid forming polyimide composite material, and can reduce the cost and realize batch application.

Description

Technical Field

[0001] This invention belongs to the field of liquid molding of composite materials and relates to a method for continuous preparation of pre-shaped fabrics with toughening function. Background Technology

[0002] Composite materials possess properties such as high specific strength, high specific stiffness, fatigue resistance, and corrosion resistance. They are widely used in new civil and military aircraft and aviation equipment, which can significantly reduce the structural weight of the airframe, improve the overall performance of the aircraft, and play a crucial role in the lightweighting, stealth, high performance, and miniaturization of military aircraft.

[0003] Liquid molding of composite materials is the most successful composite molding process developed after autoclave molding, and also the most successful low-cost non-autoclave composite molding process. Liquid molding processes used in aircraft structures mainly include resin transfer molding (RTM), resin film melt impregnation (RFI), and vacuum-assisted resin impregnation (VARI). The principle of resin transfer molding (RTM) is as follows: a dry fiber or fabric preform is placed in a mold. Under pressure injection or external vacuum assistance, liquid, reactive, low-viscosity resin flows through and fills the closed mold, expelling gas while simultaneously wetting and impregnating the dry fiber structure. After impregnation, the resin cures within the mold through a thermally initiated cross-linking reaction, ultimately yielding the molded product. RTM is a rapidly developing molding process suitable for producing a wide variety of high-quality, medium-volume advanced composite products. Pre-formed fabrics are the primary material for preform placement in RTM.

[0004] Polyimide composites possess excellent thermal oxidation stability and good comprehensive mechanical properties, enabling long-term use in high-temperature environments. They are widely used in cold-end components of aero-engines and high-temperature aerospace components. However, liquid-molded polyimide composites suffer from poor toughness after curing due to the low molecular weight of the matrix resin. This results in insufficient interlaminar toughness and impact damage resistance, with interlaminar properties significantly lower than intralaminar properties. Under impact loads, stress concentration easily occurs in the interlaminar region. Interlaminar toughening technology is an effective way to improve the toughness, impact resistance, and delamination resistance of composite materials. Imparting toughening function to carbon fiber fabrics during pre-molding not only improves the interlaminar toughness of the composite material but also greatly increases efficiency, making it suitable for mass production applications.

[0005] CN108284619A discloses an interlaminar toughened composite material, its preparation method, and its application. It uses nanofiber carbon strips as a braid to weave the reinforcement in the thickness direction. The addition of strips prevents voids between the reinforcements, thus avoiding large stress concentration points in the composite material and improving its interlaminar properties. However, this invention, which uses a braiding method to improve the interlaminar properties of the composite material, is complex to operate, unsuitable for industrial applications, and has no effect on the matrix resin, making it unsuitable for liquid-molded polyimide composites. Summary of the Invention

[0006] To address the aforementioned problems, the present invention aims to provide a simple and easy-to-operate method for the continuous preparation of pre-formed fabrics with toughening function. This preparation method is novel in concept, unique in design, and suitable for mass production applications. It can significantly improve the interlaminar toughness and impact damage resistance of liquid-formed polyimide composite materials, thereby meeting the application requirements of liquid-formed polyimide composite materials in the aerospace field.

[0007] To achieve the above objectives, the present invention provides a method for the continuous preparation of a pre-shaped fabric with toughening function, characterized in that it includes:

[0008] (1) First, the existing continuous preparation system for shaped fabrics is modified by adding a toughening material unwinding device and a second powder spreading device, as well as a heating and melting shaping drying tunnel ②;

[0009] (2) Place the carbon fiber fabric and toughening film material on the carbon fiber fabric unwinding device and toughening material unwinding device of the shaping fabric continuous preparation system;

[0010] (2) The carbon fiber fabric is desized at high temperature through a high-temperature drying tunnel;

[0011] (3) The carbon fiber fabric passes through the first powder spreading device, and the setting agent is evenly spread on the surface of the carbon fiber fabric according to the set parameters.

[0012] (4) The toughening film is spread onto the carbon fiber fabric and pressed together by the rolling roller; then it passes through the first medium-temperature drying tunnel to melt the setting agent, thereby bonding the carbon fiber fabric and the toughening film together tightly.

[0013] (5) After passing through the second powder-spreading device, the setting agent is evenly spread on the surface of the toughening film according to the set parameters. Then, it passes through the second medium-temperature drying tunnel to melt the setting agent on the surface of the toughening film and stick it to the surface of the toughening film. Finally, it passes through the winding device to roll up the pre-shaped fabric with the toughening film.

[0014] The carbon fiber fabric is a unidirectional cord fabric or plain weave fabric, and the carbon fiber is domestically produced T800 grade carbon fiber with an areal density of 100 g / m³. 2 ~300g / m 2 The width is 500mm to 1500mm, and the thickness of a single layer after curing is 0.1-0.3mm.

[0015] The toughened film is a thermosetting polyimide nanofiber film with a thickness of 30-60 μm and a surface weight of 3-5 g / m³. 2 .

[0016] The highest temperature in the high-temperature drying tunnel is above 400℃, and the desizing temperature is 370℃~400℃.

[0017] The amount of setting agent applied by the first powder-spreading device is 2%-5% of the surface density of the carbon fiber fabric, and the conveying speed of the carbon fiber fabric is (3-10) m / min.

[0018] The toughening material is flattened by rollers and bonded to carbon fiber fabric with a setting agent on its surface. After being heated and set in the first medium-temperature drying tunnel, they are tightly bonded together.

[0019] After the carbon fiber fabric is bonded together with the toughening material, it is subjected to a second powder spreading device, and the amount of setting agent spread is 2%-5% of the surface density of the carbon fiber fabric.

[0020] The second medium-temperature drying tunnel has a heating and melting temperature of 130℃ to 160℃.

[0021] Advantages of the present invention

[0022] In the preparation of carbon fiber pre-formed fabric, the present invention uses a setting agent to heat and melt to bond toughening material to carbon fiber fabric, forming a pre-formed fabric with toughening function. This can improve the interlaminar toughness and impact damage resistance of liquid-molded polyimide composite material, and can also be produced continuously, making it suitable for mass application of interlaminar toughened composite materials.

[0023] The advantages of this invention are that the toughening material and carbon fiber fabric are bonded together during pre-forming using a setting agent. The toughening material is evenly spread on the surface of the carbon fiber fabric, and the two have a good bonding effect. This results in good layup processability during preform preparation, facilitating the preparation of preforms with interlayer toughening. This invention does not add any extra steps, is simple to operate, has strong feasibility for engineering applications, and possesses significant application value.

[0024] This invention provides a simple and convenient solution to the problems of insufficient interlayer toughness and impact resistance in liquid-molded polyimide composites, and is suitable for mass production, filling the application gaps of liquid-molded polyimide composites. Attached Figure Description

[0025] Figure 1 Continuous preparation process of pre-shaped fabrics with toughening function. Detailed Implementation

[0026] To provide a clearer understanding of the technical features, objectives, and beneficial effects of the present invention, the technical solution of the present invention will now be described in detail with reference to the accompanying drawings and embodiments, but this should not be construed as limiting the scope of the present invention.

[0027] Thermosetting polyimide nanofiber membranes were designed and used as interlayer toughening films to improve the interlayer toughness and impact damage resistance of liquid-molded polyimide composites.

[0028] A method for continuous preparation of a pre-shaped fabric with toughening function, comprising:

[0029] (1) First, the existing continuous preparation system for shaped fabrics is modified by adding a toughening material unwinding device and a second powder spreading device, as well as a heating and melting shaping drying tunnel ②;

[0030] (2) Place the carbon fiber fabric and toughening film material on the carbon fiber fabric unwinding device and toughening material unwinding device of the shaping fabric continuous preparation system;

[0031] (2) The carbon fiber fabric is desized at high temperature through a high-temperature drying tunnel;

[0032] (3) The carbon fiber fabric passes through the first powder spreading device, and the setting agent is evenly spread on the surface of the carbon fiber fabric according to the set parameters.

[0033] (4) The toughening film is spread onto the carbon fiber fabric and pressed together by the rolling roller; then it passes through the first medium-temperature drying tunnel to melt the setting agent, thereby bonding the carbon fiber fabric and the toughening film together tightly.

[0034] (5) After passing through the second powder-spreading device, the setting agent is evenly spread on the surface of the toughening film according to the set parameters. Then, it passes through the second medium-temperature drying tunnel to melt the setting agent on the surface of the toughening film and stick it to the surface of the toughening film. Finally, it passes through the winding device to roll up the pre-shaped fabric with the toughening film.

[0035] The carbon fiber fabric is a unidirectional cord fabric or plain weave fabric, and the carbon fiber is domestically produced T800 grade carbon fiber with an areal density of 100 g / m³. 2 ~300g / m 2 The width is 500mm to 1500mm, and the thickness of a single layer after curing is 0.1-0.3mm.

[0036] The toughened film is a thermosetting polyimide nanofiber film with a thickness of 30-60 μm and a surface weight of 3-5 g / m³.2 .

[0037] The highest temperature in the high-temperature drying tunnel is above 400℃, and the desizing temperature is 370℃~400℃.

[0038] The amount of setting agent applied by the first powder-spreading device is 2%-5% of the surface density of the carbon fiber fabric, and the conveying speed of the carbon fiber fabric is (3-10) m / min.

[0039] The toughening material is flattened by rollers and bonded to carbon fiber fabric with a setting agent on its surface. After being heated and set in the first medium-temperature drying tunnel, they are tightly bonded together.

[0040] After the carbon fiber fabric is bonded together with the toughening material, it is subjected to a second powder spreading device, and the amount of setting agent spread is 2%-5% of the surface density of the carbon fiber fabric.

[0041] The second medium-temperature drying tunnel has a heating and melting temperature of 130℃ to 160℃.

[0042] Thermosetting polyimide nanofiber membranes were designed and used as interlayer toughening films to improve the interlayer toughness and impact resistance of liquid-molded polyimide composites. First, a setting agent powder was evenly sprinkled onto the surface of a carbon fiber fabric using a powder-spreading device, and the toughening material was spread onto the surface of the carbon fiber fabric. After heating in an oven tunnel, the setting agent melted, tightly bonding the carbon fiber fabric and the toughening material together. Then, a second powder-spreading device was used to spread setting agent powder onto the surface of the toughening material, and after heating and melting in an oven tunnel, it adhered to the surface of the toughening material. Finally, the fabric was wound up using a winding device to obtain a pre-formed fabric with toughening properties.

[0043] Example:

[0044] Step 1: Take a roll that is 100m long, 1m wide, and has a surface density of 220g / m³. 2 The carbon fiber unidirectional cord fabric and polyimide nanofiber membrane are placed on the carbon fiber fabric unwinding device and the toughening material unwinding device, connected to the traction roller, passed through the drying tunnel and roller, and connected to the winding device.

[0045] Step 2: Take 5-6 kg of setting agent powder and sprinkle it evenly into the feeding trough of the two powder spreading devices, and mix it evenly by rotating the internal extrusion roller;

[0046] Step 3: Set the heating temperatures of the high-temperature drying tunnel and the medium-temperature drying tunnel to 380℃ and 150℃ respectively, and turn on the heating of the high-temperature drying tunnel and the medium-temperature drying tunnel.

[0047] Step 4: After the drying tunnel reaches the set temperature, set the carbon fiber fabric conveying speed to 5m / min, adjust the powder spreading speed of the powder spreading device, and control the amount of powder to be 7% to 8% of the fabric surface density;

[0048] Step 5: Set the traction force to 200N, start the equipment for trial operation, and adjust the spreading state of the fabric and toughening membrane during the process to ensure that the fabric and toughening membrane are flat and aligned. Then start the entire line to complete the preparation of the pre-shaped fabric with toughening membrane.

Claims

1. A continuous preparation method for a pre-shaped fabric with toughening function, characterized in that, include: (1) First, the existing continuous preparation system for shaped fabrics is modified by adding a toughening material unwinding device and a second powder spreading device, as well as a heating and melting shaping drying tunnel ②; (2) Place the carbon fiber fabric and toughening film material on the carbon fiber fabric unwinding device and toughening material unwinding device of the shaping fabric continuous preparation system; (2) The carbon fiber fabric is desized at high temperature through a high-temperature drying tunnel; (3) The carbon fiber fabric passes through the first powder spreading device, and the setting agent is evenly spread on the surface of the carbon fiber fabric according to the set parameters. (4) The toughening film is spread onto the carbon fiber fabric and pressed together by the rolling roller; then it passes through the first medium-temperature drying tunnel to melt the setting agent, thereby bonding the carbon fiber fabric and the toughening film together tightly. (5) After passing through the second powder-spreading device, the setting agent is evenly spread on the surface of the toughening film according to the set parameters. Then, it passes through the second medium-temperature drying tunnel to melt the setting agent on the surface of the toughening film and stick it to the surface of the toughening film. Finally, it passes through the winding device to roll up the pre-shaped fabric with the toughening film.

2. The method for continuous preparation of a pre-shaped fabric with toughening function according to claim 1, characterized in that, The carbon fiber fabric is a unidirectional cord fabric or plain weave fabric, and the carbon fiber is domestically produced T800 grade carbon fiber with an areal density of 100 g / m³. 2 ~300g / m 2 The width is 500mm to 1500mm, and the thickness of a single layer after curing is 0.1-0.3mm.

3. The method for continuous preparation of a pre-shaped fabric with toughening function according to claim 1, characterized in that, The toughened film is a thermosetting polyimide nanofiber film with a thickness of 30-60 μm and a surface weight of 3-5 g / m³. 2 .

4. The method for continuous preparation of a pre-shaped fabric with toughening function according to claim 1, characterized in that, The highest temperature in the high-temperature drying tunnel is above 400℃, and the desizing temperature is 370℃~400℃.

5. The method for continuous preparation of a pre-shaped fabric with toughening function according to claim 1, characterized in that, The amount of setting agent applied by the first powder-spreading device is 2%-5% of the surface density of the carbon fiber fabric, and the conveying speed of the carbon fiber fabric is (3-10) m / min.

6. The method for continuous preparation of a pre-shaped fabric with toughening function according to claim 1, characterized in that, The toughening material is flattened by rollers and bonded to carbon fiber fabric with a setting agent on its surface. After being heated and set in the first medium-temperature drying tunnel, they are tightly bonded together.

7. The method for continuous preparation of a pre-shaped fabric with toughening function according to claim 1, characterized in that, After the carbon fiber fabric and toughening material are bonded together, they are subjected to a second powder spreading device. The amount of setting agent spread is 2%-5% of the areal density of the carbon fiber fabric.

8. The method for continuous preparation of a pre-shaped fabric with toughening function according to claim 1, characterized in that, The second medium-temperature drying tunnel has a heating and melting temperature of 130℃ to 160℃.

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