A profiled composite material and a method of forming the same

Abstract

The application discloses a special-shaped composite material and a forming method thereof, and solves the problem of poor mechanical properties of a special-shaped part of the special-shaped composite material by means of structural design and cooperation of a mold to reinforce the special-shaped part. The special-shaped composite material comprises a base body and a reinforcing body, and the reinforcing body comprises, from inside to outside, reinforcing fabric or reinforcing fabric belt and three-dimensional spacer fabric. The special-shaped composite material has a hollow cylindrical structure, a smooth outer wall and a concave-convex staggered zigzag inner wall. The fiber volume content of the inner wall is greater than or equal to 80%, and the fiber volume content of the outer wall is less than or equal to 30%.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of composite material forming, in particular to a special-shaped composite material forming method. BACKGROUND

[0002] Special-shaped composite parts have various forms and contain various complex shapes, and are in great demand in the industries of unmanned aerial vehicles, automobile parts, robots and the like.

[0003] The forming processes of the existing special-shaped composite materials mainly include winding, hand lay-up, mold pressing and injection molding. In the process of preparing the special-shaped composite materials, the fibers formed by winding are not easy to be accurately arranged along the axial direction, and the structure outer surface is not a mold surface, so the appearance and flatness are poor. The stability of the hand lay-up formed part is poor, and the part quality is closely related to the proficiency of the operator. The mold pressing process is easy to cause defects in the special-shaped part, and is not suitable for preparing special-shaped rotary body composite materials. The internal reinforcing fibers of the special-shaped composite material produced by the injection molding process are short fibers, the forming speed is fast, but the mechanical properties are poor. SUMMARY

[0004] In order to overcome the defects in the prior art, the technical problem to be solved by the present application is to provide a special-shaped composite material and a forming method thereof, which enhances the special-shaped part through structure design and cooperation with the mold, and solves the problem of poor mechanical properties of the special-shaped part of the special-shaped composite material.

[0005] In order to achieve the above-mentioned purpose, the present application provides the following technical scheme:

[0006] A special-shaped composite material comprises a matrix and a reinforcing body, wherein: the reinforcing body comprises, from the inside to the outside, reinforcing fabric or reinforcing tape and three-dimensional spacer fabric.

[0007] Further, the special-shaped composite material is a hollow cylindrical structure, the outer wall is smooth, and the inner wall is a concave-convex staggered sawtooth shape.

[0008] Further, the fiber volume content of the inner wall of the special-shaped composite material is greater than or equal to 80% (the rest is the matrix), and the fiber volume content of the outer wall is less than or equal to 30% (the rest is the matrix), so that the mass of this part is reduced, the density of the entire part is reduced, and the effect of lightweight is achieved.

[0009] Further, the reinforcing body comprises one or more of glass fiber unidirectional tape, glass fiber fabric, carbon fiber unidirectional tape, carbon fiber fabric, aramid fiber unidirectional tape, aramid fiber fabric, aramid fiber tape, ultra-high molecular weight polyethylene fabric and ultra-high molecular weight polyethylene tape.

[0010] Further, the reinforcing fabric is 2-20 layers of superimposed fabric.

[0011] Further, the reinforcing fabric has a thickness of 0.2-4 mm and a width of 5-40 mm.

[0012] Further, the matrix comprises one or more of epoxy resin, phenolic resin, polyester resin and bismaleimide resin.

[0013] Further, the profiled composite material has a compression strength of ≥240 MPa, a tensile strength of ≥230 MPa, a tensile elastic modulus of ≥11.5 GPa and an impact strength of ≥176 KJ / m2.

[0014] The application provides a profiled composite material forming method, and the technical scheme is as follows:

[0015] S1: mold preparation, the mold for forming the profiled composite material comprises an upper cover plate, a lower cover plate, a side plate connecting the upper cover plate and the lower cover plate and a core mold group located inside the side plate; the core mold group comprises a center rod, large core molds and small core molds; the transverse section of each of the large core molds and the small core molds is a fan-shaped section, the longitudinal section has concave-convex staggered sawtooth shapes on the outer side, the two large core molds and the two small core molds are spliced to form a hollow cylinder inside, and the center rod passes through the hollow cylinder, the upper cover plate and the lower cover plate;

[0016] S2: the core mold group is wrapped with a high-temperature-resistant isolation film;

[0017] S3: the reinforcing fabric or the reinforcing fabric with different angles is used to reinforce the recessed part outside the core mold, and the fiber filaments are used to fix the reinforcing fabric or the reinforcing fabric to the recessed part on the surface of the core mold;

[0018] S4: a layer of three-dimensional spacer fabric is filled outside the reinforcing fabric or the reinforcing fabric, so that the upper and lower layers of the spacer fabric respectively contact the internal reinforcing fabric or the reinforcing fabric and the inner wall part of the mold;

[0019] S5: a vacuum bag film is wrapped outside the mold, and a sealing strip is connected to form a closed space structure; the matrix material is injected into the mold through vacuum negative pressure to obtain an encapsulation mold containing the profiled composite material;

[0020] S6: under the condition of ensuring that the vacuum negative pressure in the mold is maintained, the mold is first heated to 30-100 DEG C and kept for 60-180 min, and then heated to 100-200 DEG C and kept for 60-180 min;

[0021] S7: the encapsulation mold is cooled to below 50 DEG C and then demolded to obtain the profiled composite material.

[0022] Further, the upper cover plate has two holes, one of which is used for guiding the matrix material to enter, and the other of which is used for guiding the matrix material to exit.

[0023] The above technical solution is only one possible technical solution of the present application, and the protection scope of the present application is not limited to this.

[0024] The above-mentioned application has the following advantages or beneficial effects:

[0025] 1. The special fabric structure is used to enhance the special-shaped part of the special-shaped composite material, so as to provide higher mechanical properties for the special-shaped part, and the forming method is convenient and fast.

[0026] 2. The three-dimensional spacer fabric is used to fill in the outer wall of the special-shaped composite material, which can not only enhance the mechanical properties of the whole product, but also reduce the product quality and realize lightweight.

[0027] 3. The core mold adopts a combination, which is coated with an isolation film, and has high rigidity after combination, can provide high inner wall quality for the complex inner wall shape of the special-shaped composite material, is easy to remove, is convenient to demold from the complex inner cavity after forming is completed, can be repeatedly used, and reduces the cost. BRIEF DESCRIPTION OF DRAWINGS

[0028] Figure 1 is a front view structural schematic diagram of the mold and the special-shaped composite material of the present application;

[0029] Figure 2 is a three-dimensional schematic diagram of the mold and the special-shaped composite material of the present application;

[0030] Figure 3 is a top view of the core mold combination of the present application;

[0031] Figure 4 is a three-dimensional view of the core mold combination of the present application;

[0032] Figure 5 is a three-dimensional schematic diagram of the special-shaped composite material of the present application;

[0033] Figure 6 is Figure 5 a sectional view along the diameter;

[0034] Figure 7 is a schematic diagram of the inner reinforcing fabric of the special-shaped composite material of the present application;

[0035] Figure 8 is a schematic diagram of the inner reinforcing fabric tape of the special-shaped composite material of the present application;

[0036] Figure 9 is Figure 5 a top view.

[0037] In the figure: 1, outer mold; 2, mold core; 3, profiled composite material; 101, upper cover plate; 102, lower cover plate; 103, side plate; 201, center rod; 202, screw thread; 203, nut; 204, core mold set; 205, large core mold; 206, small core mold; 301, high-temperature-resistant isolation film; 302, multi-layer reinforcing fabric; 303, three-dimensional spacer fabric; 304, matrix material; 305, inner wall profiled part; 306, reinforcing tape. DETAILED DESCRIPTION

[0038] The application will be further described in conjunction with the accompanying drawings and specific examples, but not as a limitation of the application.

[0039] Example 1

[0040] Please refer to Figure 7 A method for forming a glass fiber reinforced profiled composite material includes the following steps:

[0041] S1. Clean each part of the mold and apply two layers of release agent.

[0042] S2. Cover the outer surface of the core mold set 204 with a layer of high-temperature-resistant isolation film 301 to make it closely adhere to the core mold.

[0043] S3. Cut the glass fiber fabric according to the size and shape of the core mold, and the glass fiber fabric used is s-glass twill fabric.

[0044] S4. Fix the above-mentioned glass fiber fabric 302 on the profiled surface of the core mold with glass fiber filaments to make it closely adhere to the surface of the core mold, and overlap 5 layers of fabric, with fabric angles of (0°, 30°, 0°, -30°, 0°), and a single layer thickness of 0.4mm.

[0045] S5. Fill a layer of three-dimensional glass fiber spacer fabric 303 outside the glass fiber fabric, so that the upper and lower surfaces of the spacer fabric respectively contact the outer surface of the inner glass fiber fabric and the inner wall part of the outer mold.

[0046] S6. Cover the outer surface of the mold with a vacuum bag film, and connect it with a sealing strip to form a closed space structure. Inject resin 304 into the inside of the mold through vacuum negative pressure to obtain an encapsulated mold containing a glass fiber reinforced profiled composite material, and the resin is phenolic resin.

[0047] S7. Under the condition of ensuring that the inside of the mold maintains vacuum negative pressure, cure the above-mentioned encapsulated mold, and the curing conditions are as follows: heat at a rate of 1-2℃ / min to 120℃, keep for 80min, and then cool at a rate not greater than 3℃ / min to room temperature.

[0048] S8. After cooling the above-mentioned encapsulated mold to room temperature, demold to obtain the glass fiber reinforced profiled composite material, as shown inFigure 6 as shown.

[0049] The compression strength of the shaped part of the inner wall of the shaped composite material sample prepared in this embodiment is 240.56 MPa.

[0050] Example 2

[0051] See Figure 8 A method for forming aramid-reinforced shaped composite material includes the following steps:

[0052] S1. Clean each part of the mold and apply two layers of release agent.

[0053] S2. Wrap a layer of high-temperature-resistant release film 301 around the outer surface of the core mold set 204 so that it closely adheres to the core mold.

[0054] S3. Cut the aramid tape according to the size and shape of the core mold. The aramid tape used is 2 mm thick and 2 cm wide.

[0055] S4. Fix the aramid tape 306 described above to the shaped part of the surface of the core mold with aramid filaments, so that it closely adheres to the shaped part of the surface of the core mold.

[0056] S5. Fill a layer of three-dimensional aramid spacer fabric 303 outside the aramid tape, so that the upper and lower surfaces of the spacer fabric respectively contact the outer surface of the inner aramid tape and the inner wall part of the outer mold.

[0057] S6. Wrap a vacuum bag film outside the mold and connect it with a sealing strip to form a closed space structure. Inject resin (304) into the inside of the mold through vacuum negative pressure to obtain an encapsulated mold containing aramid-reinforced shaped composite material. The resin is epoxy resin E44, the curing agent is polyetheramine, and the ratio of epoxy resin to curing agent is 3:1.

[0058] S7. Under the condition of ensuring that the inside of the mold maintains vacuum negative pressure, cure the encapsulated mold. The curing conditions are as follows: increase the temperature to 50°C at a rate of 1-2°C / min, maintain the temperature for 60 min, then increase the temperature to 100°C at a rate of 1-2°C / min, maintain the temperature for 60 min, and finally cool to room temperature at a rate not greater than 3°C / min.

[0059] S8. After cooling the encapsulated mold to room temperature, demold to obtain the aramid-reinforced shaped composite material, as shown in Figure 6 .

[0060] The compression strength of the shaped part of the inner wall of the shaped composite material sample prepared in this embodiment is 365.24 MPa.

[0061] Table 1 compares the performance of the samples prepared by the embodiments of the present application and the existing forming method.

[0062] Table 1 Performance Comparison

[0063]

[0064] Those skilled in the art should understand that the skilled in the art can realize the variations in combination with the prior art and the above-mentioned embodiments, which are not described here. Such variations do not affect the essential content of the present application and are not described here.

[0065] The preferred embodiments of the present application are described above. It should be understood that the present application is not limited to the specific embodiments described above, and that the devices and structures not described in detail should be understood as being implemented in the ordinary way in the art; any person skilled in the art can make many possible changes and modifications to the present application or modify it as equivalent embodiments without departing from the scope of the present application, which does not affect the essential content of the present application. Therefore, any simple modification, equivalent change and modification of the above embodiments made in accordance with the technical essence of the present application without departing from the scope of the present application are still within the scope of protection of the present application.

Claims

1. A method of forming a profiled composite material, characterised by It comprises the following steps: S1: mold preparation, the mold for forming the special-shaped composite material comprises an upper cover plate, a lower cover plate, side plates connecting the upper cover plate and the lower cover plate, and a core mold group inside the side plates; the core mold group comprises a center rod, large core molds and small core molds; the transverse section of the large core mold and the small core mold is a fan-shaped, the longitudinal section has staggered sawtooth-shaped concave-convex on the outside, the two large core molds and the two small core molds are spliced to form a hollow cylinder inside, the center rod passes through the hollow cylinder, the upper cover plate and the lower cover plate; S2: the core mold group is wrapped with a high-temperature-resistant isolation film; S3: the reinforcing fabric with different angles is used to reinforce the recessed part outside the core mold, and the fiber filament is used to fix the reinforcing fabric on the recessed part of the surface of the core mold; S4: a layer of three-dimensional spacer fabric is filled outside the reinforcing fabric, so that the upper and lower layers of the spacer fabric respectively contact the internal reinforcing fabric and the inner wall part of the mold; S5: a vacuum bag film is wrapped outside the mold, and a sealed space structure is formed by connecting the sealing strips, the matrix material is injected into the mold through vacuum negative pressure, and a packaging mold containing the special-shaped composite material is obtained; S6: under the condition of ensuring that the vacuum negative pressure in the mold is maintained, curing is carried out, first heated to 30-100℃ for 60-180min, then heated to 100-200℃ for 60-180min; S7: the packaging mold is cooled to below 50℃ after the above steps, and the special-shaped composite material is obtained.

2. The method of claim 1, wherein: The upper cover plate comprises two holes, one hole is used for the introduction of the matrix material, and the other hole is used for the export of the matrix material.

3. The method of claim 1, wherein: The reinforcing fabric comprises a reinforcing tape.

4. A profiled composite material as claimed in claim 1 or 2, comprising a matrix and a reinforcement, characterised in that: The reinforcing body comprises, from inside to outside, the reinforcing fabric, the three-dimensional spacer fabric.

5. The contoured composite of claim 4, wherein: The reinforcing fabric comprises a reinforcing tape.

6. The contoured composite of claim 4, wherein: The special-shaped composite material is a hollow cylindrical structure, the outer wall is smooth, and the inner wall is staggered sawtooth-shaped concave-convex.

7. The contoured composite of claim 4, wherein: The reinforcing fabric is stacked 2-20 layers.

8. The contoured composite of claim 4, wherein: The matrix comprises one or more of epoxy resin, phenolic resin, polyester resin and bismaleimide resin.

9. The contoured composite of claim 4, wherein: The profiled composite material has compression strength ≥ 240 MPa, tensile strength ≥ 230 MPa, tensile elastic modulus ≥ 11.5 GPa, and impact strength ≥ 176 KJ / m 2 .

10. The contoured composite of claim 5, wherein: The reinforcing tape has a thickness of 0.2-4mm and a width of 5-40mm.

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