A method for preparing a composite carbon fiber tape containing inorganic nonwoven yarn

Abstract

The present invention relates to a method for preparing a composite carbon fiber tape containing inorganic non-woven gauze. The method comprises: cutting inorganic fibers into short fibers, then placing them in water, conveying the obtained fiber suspension slurry to a web-forming mechanism to form the inorganic fibers into a wet non-woven gauze, drying, adding a binder, curing, and obtaining a dry non-woven gauze; adding a binder to the upper and lower surfaces of unidirectional carbon fibers, attaching the dry non-woven gauze to the upper and lower surfaces of the unidirectional carbon fibers, and hot pressing. The method has a relatively simple process, is easy to operate, has good repeatability, and is low in cost; the composite material products subsequently produced from the composite carbon fiber tape have fewer internal defects and good resistance to interlayer damage.

Description

Technical Field

[0001] The invention belongs to the field of preparation of fiber-reinforced composite materials, and particularly relates to a method for preparing a composite carbon fiber tape containing inorganic non-woven mesh yarn. Background Art

[0002] Fiber-reinforced composite materials have low specific gravity, high specific strength and specific modulus, and excellent chemical stability, shock absorption, wear resistance, heat resistance, fatigue resistance and other excellent properties. They are widely used in aerospace, military, automotive and other fields, which can effectively reduce weight, save costs and improve market competitiveness. Compared with the autoclave molding commonly used in the aerospace field, liquid molding has lower costs, saves the time spent on prepreg process and autoclave, improves the weight reduction efficiency of composite structures, and has become a molding method that is widely studied. However, in the liquid molding preparation process, since the dry fibers used are generally not surface treated, the wettability between the fibers and the matrix resin is poor, and the fibers will move during the resin flow process, thereby affecting the performance of the product. In addition, due to the high brittleness of the matrix resin, the impact resistance of composite products is poor, and the parts cannot be used in practice.

[0003] Chinese patent CN109895469A discloses a method for optimizing the interfacial properties of epoxy carbon fiber composite material system, which adds a layer of resin film between carbon fiber and thermoplastic material (powder, film or non-woven fabric), pre-coats the resin film on the surface of carbon fiber (unidirectional fiber, carbon fiber fabric), and then adds thermoplastic material (powder, film or non-woven fabric) to the surface of the material. The advantage of this method is that it can solve the problem of poor compression and interlayer shear performance caused by weak interface bonding when using "intercalation" thermoplastic material toughening liquid to form epoxy carbon fiber composite material system, and does not reduce its interfacial properties while toughening. The disadvantage is that the resin film and thermoplastic (film and non-woven fabric) are inconsistent with the matrix resin deformation during curing, which will cause defects, and the thickness and uniformity of the resin film are difficult to control, and the fiber volume content is difficult to control.

[0004] Chinese patent CN104943200A discloses a method for liquid molding of a resin-based composite material of a sandwich thermoplastic guide net, which places the thermoplastic guide net on the surface of a fiber fabric or between fiber fabrics, and adopts a composite material liquid molding method to form a resin-based composite material of a sandwich thermoplastic guide net. The invention uses thermoplastic resin material to process the guide net, which can not only be laid on the surface of the fiber fabric, but also laid in the middle of the fiber fabric ply, and serves as a guide medium during the resin filling process of composite molding to improve the flow and penetration of the resin. The advantage of the invention is that the guide net can be retained inside the composite material structure and play a toughening role, reduce the generation of dry spot defects, and improve the molding quality. In addition, the surface of the molded product can be free of indentations, improve the surface quality of the product, reduce demoulding time and post-processing, and improve labor efficiency. The disadvantage is that the thermoplastic resin guide net will produce defects when it is cured due to different deformations from the resin during curing, and the thickness of the thermoplastic resin guide net may cause damage to the mechanical properties of the composite product.

[0005] Chinese patent CN103072289A discloses a method for improving the interlayer toughness of fiber-reinforced resin-based composite materials. The method disperses low-content nanoparticles in the resin, which is conducive to achieving uniform dispersion of nanoparticles. By coating a filter membrane with a specific pore size on the surface of the fiber preform, the scouring effect of the resin on the nanoparticles during the liquid molding process is reduced. At the same time, the nanoparticles are enriched between the composite material layers by suction filtration, so that the nanoparticles in the resin system are changed from "thin" to "concentrated", thereby effectively solving the contradiction between the dispersibility and high content of nanoparticles. The advantages of this method are good compatibility with the liquid molding process, easy operation, low cost, convenient application, and can achieve uniform dispersion of nanoparticles. The disadvantages are that the concentration of the particles is uncontrollable and the product stability is poor. Summary of the invention

[0006] The technical problem to be solved by the present invention is to provide a method for preparing a composite carbon fiber tape containing inorganic non-woven mesh yarn, so as to overcome the defects of poor mechanical properties of fiber-reinforced composite materials in the prior art.

[0007] The present invention provides a method for preparing a composite carbon fiber tape containing an inorganic nonwoven mesh, comprising the following steps:

[0008] (1) cutting one or more inorganic fibers selected from carbon fiber, glass fiber, silicon carbide fiber, boron fiber, and quartz fiber into short fibers, and then placing them in water, and conveying the obtained fiber suspension slurry to a web-forming mechanism to form a wet nonwoven mesh of the inorganic fibers;

[0009] (2) drying the wet nonwoven mesh in step (1), adding a binder, and curing to obtain a dry nonwoven mesh;

[0010] (3) Adding a binder to the upper and lower surfaces of the unidirectional carbon fiber, attaching the dry non-woven mesh in step (2) to the upper and lower surfaces of the unidirectional carbon fiber, and hot pressing to obtain a composite carbon fiber tape containing an inorganic non-woven mesh.

[0011] Preferably, in step (1), the short fibers have a diameter of 5 to 20 μm and a length of 3 to 12 mm.

[0012] Preferably, the fiber suspension concentration in step (1) is 5% to 10%.

[0013] Preferably, the drying temperature in step (2) is 110-150°C.

[0014] Preferably, in step (2), the curing temperature is 160 to 220° C., and the curing time is 20 to 40 minutes.

[0015] Preferably, the binder in step (2) is a liquid mixture of polyimide and polyphenylene sulfide in a mass ratio of 1:0.5-1, with a viscosity of 2500cP-5000cP, and the mass of the binder is 3-8% of the mass of the non-woven mesh after drying.

[0016] Preferably, in step (2), the dry nonwoven mesh has an area weight of 6 to 12 gsm and a thickness of 20 to 40 μm.

[0017] Preferably, in step (3), the binder is a liquid mixture of polyimide and polyphenylene sulfide in a mass ratio of 1:0.5-1, with a viscosity of 2500cP-5000cP, and the mass of the binder is 3-8% of the mass of the unidirectional carbon fiber.

[0018] Preferably, in step (3), the thickness of the unidirectional carbon fiber is 200-400 μm.

[0019] Preferably, the process parameters of hot pressing in step (3) are: temperature of 250-300° C., pressure of 0.5-3 MPa, and time of 1-3 hours.

[0020] The present invention also provides a composite carbon fiber tape containing inorganic non-woven mesh yarn prepared by the above preparation method.

[0021] The invention also provides an application of a composite carbon fiber tape containing an inorganic nonwoven mesh in aerospace.

[0022] Beneficial Effects

[0023] (1) The process of the present invention is relatively simple, easy to operate, has good repeatability and low cost;

[0024] (2) The composite material products produced by using the composite carbon fiber tape prepared by the present invention have fewer internal defects, good resistance to interlaminar damage, and a post-impact compression strength greater than 300 MPa. DETAILED DESCRIPTION

[0025] The present invention will be further described below in conjunction with specific embodiments. It should be understood that these embodiments are only used to illustrate the present invention and are not intended to limit the scope of the present invention. In addition, it should be understood that after reading the content taught by the present invention, those skilled in the art can make various changes or modifications to the present invention, and these equivalent forms fall within the scope limited by the appended claims of the application equally.

[0026] Example 1

[0027] (1) Cutting carbon fibers and glass fibers with a diameter of 7 μm into short fibers with a length of 5 mm, placing the short fibers in an aqueous medium to prepare a fiber suspension slurry with a concentration of 5%, and then transporting the fiber suspension slurry to a web-forming mechanism to form a wet nonwoven mesh with inorganic fibers;

[0028] (2) a liquid adhesive having a viscosity of 3000 cP obtained by mixing polyimide and polyphenylene sulfide in a mass ratio of 1:0.5;

[0029] (3) the wet nonwoven mesh is placed at 120° C. to be fully dried, and then 4% by mass of the binder in step (2) is added, and the nonwoven mesh is cured at 180° C. for 20 minutes to obtain a dry nonwoven mesh with an area weight of 8 gsm and a thickness of 30 μm;

[0030] (4) Add 4% by mass of the binder in step (2) to the upper and lower surfaces of unidirectional carbon fibers with a thickness of 300 μm, then attach dry non-woven mesh to the upper and lower surfaces of the unidirectional carbon fibers, and hot press at a temperature of 250°C and a pressure of 1 MPa for 2 hours to obtain a composite carbon fiber tape containing an inorganic non-woven mesh, wherein the composite carbon fiber tape has a post-impact compressive strength of 310 MPa.

[0031] Example 2

[0032] (1) Cutting carbon fibers and silicon carbide fibers with a diameter of 7 μm into short fibers with a length of 8 mm, placing the short fibers in an aqueous medium to prepare a fiber suspension slurry with a concentration of 6%, and then transporting the fiber suspension slurry to a web-forming mechanism to form a wet nonwoven mesh with inorganic fibers;

[0033] (2) a liquid adhesive having a viscosity of 4000 cP obtained by mixing polyimide and polyphenylene sulfide in a mass ratio of 1:1;

[0034] (3) the wet nonwoven mesh is placed at 120° C. to be fully dried, and then 6% by mass of the binder in step (2) is added, and the nonwoven mesh is cured at 200° C. for 30 minutes to obtain a dry nonwoven mesh having an area weight of 10 gsm and a thickness of 35 μm;

[0035] (4) Add 6% by mass of the binder in step (2) to the upper and lower surfaces of unidirectional carbon fibers with a thickness of 350 μm, then attach dry non-woven mesh to the upper and lower surfaces of the unidirectional carbon fibers, and hot press at a temperature of 280° C. and a pressure of 1.5 MPa for 2 hours to obtain a composite carbon fiber tape containing an inorganic non-woven mesh, wherein the composite carbon fiber tape has a post-impact compressive strength of 322 MPa.

Claims

1. A method for preparing a composite carbon fiber tape containing an inorganic nonwoven mesh, The following steps are involved: (1) Cutting carbon fibers and silicon carbide fibers with a diameter of 7 μm into short fibers with a length of 8 mm, placing them in a water medium to prepare a fiber suspension slurry with a concentration of 6%, and then transporting them to a web-forming mechanism to form a wet nonwoven mesh with inorganic fibers; (2) a liquid adhesive having a viscosity of 4000 cP obtained by mixing polyimide and polyphenylene sulfide in a mass ratio of 1:1; (3) The wet nonwoven mesh is placed at 120° C. to be fully dried, and then 6% by mass of the binder in step (2) is added, and the nonwoven mesh is cured at 200° C. for 30 minutes to obtain a dry nonwoven mesh having an area weight of 10 gsm and a thickness of 35 μm; (4) Add 6% by mass of the binder in step (2) to the upper and lower surfaces of unidirectional carbon fibers with a thickness of 350 μm, and then attach dry non-woven mesh to the upper and lower surfaces of the unidirectional carbon fibers. Hot pressing is performed at a temperature of 280° C. and a pressure of 1.5 MPa for 2 hours to obtain a composite carbon fiber tape containing an inorganic non-woven mesh. The composite carbon fiber tape has a post-impact compressive strength of 322 MPa.

2. A composite carbon fiber tape containing inorganic nonwoven mesh prepared by the preparation method as claimed in claim 1.

3. Use of the composite carbon fiber tape as claimed in claim 2 in aerospace.