TWI863304B - Carbon fiber reinforced plastic sheet and manufacturing method thereof - Google Patents

Abstract

The present invention provides a carbon fiber reinforced plastic sheet and a manufacturing method thereof that achieves the expected strength. The carbon fiber reinforced plastic sheet is a sheet-like material, and the sheet-like material comprises: a phenolic resin belonging to a thermosetting resin, one or more carbon fibers with a fiber length ranging from 10 mm to 15 mm, and aromatic polyamide fibers.

Description

Carbon fiber reinforced plastic sheet and manufacturing method thereof

The present invention relates to a carbon fiber reinforced plastic plate and a manufacturing method thereof.

Thick plates made of carbon fiber reinforced plastic (hereinafter referred to as "CFRP") can be processed with high precision by super-hard cutting tools, just like metal. Due to the high price of metal and the difficulty in obtaining it, the demand for plates made of CFRP (hereinafter referred to as "CFRP plates") has increased. However, although CFRP plates are intended to make up for the demand for metal, they are not strong enough.

Regarding carbon fiber waste, a domestic aircraft manufacturer discharges 70 tons per year. Therefore, developing a method for utilizing carbon fiber waste has become an urgent issue. If a dry heat roller is used in the recycling of carbon fiber waste, the contact with the roller may cause fiber breakage and fuzz, which may lead to a decrease in carbon fiber quality. In addition, the recycling of carbon fiber waste requires additional heat treatment steps such as the resin removal step, so the steps become complicated. Therefore, the price of recycled carbon fiber obtained by recycling carbon fiber waste is high. On the other hand, regarding the utilization of carbon fiber, most of them are used in the form of non-woven fabrics for cushioning materials, sound insulation materials, etc. Therefore, it is difficult to use expensive recycled carbon fiber. If recycled carbon fiber without resin is used in high value-added explosion-proof tools, not only can the effective utilization of recycled carbon fiber be expected, but also the effect of lightweighting can be expected.

Achieving satisfactory strength by recycling carbon fibers is an important issue to promote the use of recycled carbon fibers. So far, no carbon fiber has been selected that can produce CFRP plates with the same strength as metal. The inventors of the present invention have found that by combining with a papermaking method, CFRP plates with the same strength as metal can be produced. The inventors of the present invention believe that when using the papermaking method to produce CFRP plates with the same strength as metal, recycled carbon fibers obtained by the dissolution method can be used. However, since recycled carbon fibers are only used in the form of non-woven fabrics for cushioning materials and sound insulation materials, and recycled carbon fibers are expensive and their use has not made progress, manufacturers who produce recycled carbon fibers by the dissolution method have not invested in equipment using the dissolution method as expected. Therefore, the inventors of the present invention have found that it is difficult to obtain recycled carbon fibers by dissolution. In order to increase the production of recycled carbon fibers and to easily obtain recycled carbon fibers, it is urgent to develop new uses for recycled carbon fibers.

Japanese New Model Registration No. 3225768 (Patent Document 1) discloses a tool made of carbon fiber reinforced thermoplastic resin in relation to weight reduction achieved by converting metal to resin. However, the tool made of carbon fiber reinforced thermoplastic resin is slightly insufficient in strength because of the use of thermoplastic resin.

Japanese Patent No. 2907679 (Patent Document 2) discloses a tool formed of a thermosetting resin reinforced with glass fibers. In addition, as a known example, Patent Document 2 also discloses a tool having an outer surface covered with a carbon fiber epoxy cloth. However, the tool has a strength of less than 40% of the torque of similar metal products and is used for specific purposes.

Japanese Patent No. 7005557 (Patent Document 3) discloses a CFRP plate and a method for manufacturing the same. The CFRP plate and the method for manufacturing the same can satisfy the requirements of processability, smoothness after processing, and strength, but the manufacturing steps are complicated and it is difficult to cope with situations requiring higher strength. [Prior Technical Document] [Patent Document]

Patent document 1: New Model Registration No. 3225768 Patent document 2: Japanese Patent No. 2907679 Patent document 3: Japanese Patent No. 7005557

(Invent the problem you want to solve)

The purpose of the present invention is to provide a CFRP plate and a manufacturing method thereof that achieves the desired strength. (Technical means for solving the problem)

The carbon fiber reinforced plastic sheet of the present invention is formed by using a sheet body as a plain profile, and the sheet body comprises: a phenolic resin belonging to a thermosetting resin, one or more carbon fibers with a fiber length in the range of 10 mm to 15 mm, and aromatic polyamide fibers belonging to an adhesive.

The carbon fiber of the carbon fiber reinforced plastic sheet of the present invention can be of two types: a fiber length of 10 mm and a fiber length of 15 mm.

The manufacturing method of the carbon fiber reinforced plastic plate of the present invention is as follows, that is, using a phenolic resin belonging to a thermosetting resin, one or more carbon fibers within the range of 10 mm to 15 mm in fiber length, and aromatic polyamide fibers as materials, the materials are dispersed and mixed in water in a container at a ratio of 50 wt% of the phenolic resin, 45 wt% of the carbon fibers, and 5 wt% of the aromatic polyamide fibers, and the sheet is sheeted in a sheeting frame, the sheeted mixed liquid in the sheeting frame is dehydrated in the frame, the dehydrated residue is dried to form a plain profile, the plain profile is punched by a Thomson knife, the punched plain profile is dried, and the sheet is heat-formed by a press.

The carbon fiber in the manufacturing method of the carbon fiber reinforced plastic plate of the present invention can be 22.5 wt% carbon fiber with a fiber length of 10 mm and 22.5 wt% carbon fiber with a fiber length of 15 mm.

In the past, there was no CFRP sheet made of recycled carbon fiber by the papermaking method with the same strength as metal. The flexural strength of the carbon fiber reinforced plastic sheet of the present invention is above 500 MPa.

The carbon fiber of the present invention is used in aircraft and electric vehicles that require light weight and strength. The carbon fiber is filamentous, and can also be carbon spun fiber before being wound and impregnated with epoxy resin for productization. This carbon fiber is produced in the process of manufacturing standard products, and is produced due to insufficient weight, etc., and is spun fiber or residue before resin impregnation in the final stage. The carbon fiber can also be recycled carbon fiber that is recovered by removing resin from waste carbon fibers through combustion or dissolution.

When using two different types of carbon fibers, one with a fiber length of 10 mm and one with a fiber length of 15 mm, a CFRP plate with the same strength as metal was achieved. The bending strength of the CFRP plate was over 500 MPa. As an example for confirming the strength of the carbon fiber reinforced plastic plate, a wrench with a thickness of 7 mm and a diameter of 17 mm was manufactured. The wrench achieved a torque of 55 N·m, which is more than twice the tightening torque of a general bolt. For reference, the tightening torque of a general bolt is 24.5 N·m.

Of the entire material, 45 wt% is carbon fiber, the remaining 50 wt% is phenolic resin, and 5 wt% is aromatic polyamide fiber (trade name: Twaron (registered trademark) manufactured by Toray) as a binder. The carbon fiber is 22.5 wt% carbon fiber with a fiber length of 10 mm and 22.5 wt% carbon fiber with a fiber length of 15 mm. The flexural strength of the CFRP plate made of these materials is about 550 MPa to about 600 MPa.

It is said that in carbon fiber materials such as injection molded products of thermoplastic resins, the strength of the recycled carbon fiber is best when the fiber length is 8 mm to 10 mm. If the fiber length of the recycled carbon fiber is shorter than the above length, the carbon fiber material will not generate strength. In addition, if the fiber length of the recycled carbon fiber is longer than the above length, part of the carbon fiber will appear in the product in the form of thorns, so it cannot be used. The bending strength of the carbon fiber material is about 450 MPa to 480 MPa, which is not strong enough to be used as a CFRP plate.

Therefore, in order to achieve a flexural strength of 500 MPa or more, the inventors of the present invention have clarified the optimal carbon fiber length in a CFRP plate made of a mixture of a thermosetting resin and carbon fibers by a sheet-forming method.

The CFRP plate of the present invention can provide a lightweight CFRP plate with a bending strength equivalent to that of steel, and can provide explosion-proof specifications due to its material properties.

Since carbon fibers that do not contain thermoplastic resins or thermosetting resins are suitable for papermaking, these resins can be removed by burning or dissolving to obtain recycled carbon fibers, which makes a huge contribution to the environment.

Embodiment 1 which embodies the CFRP plate of the present invention will be described with reference to the drawings.

<Example 1> As shown in FIG. 1, the CFRP plate of Example 1 is a thick plate with a thickness of 5 mm and a length and width of 90 mm and 70 mm. The shape of the CFRP plate can be made into tools such as wrenches and ratchet wrenches by changing the shape of the mold. In addition, larger tools can also be manufactured by changing the mold and the press.

As shown in FIG2 , the manufacturing method of CFRP plate is to use the papermaking method. The manufacturing method has: 1. crushing step, 2. mixing step, 3. papermaking step, 4. dehydration and pressurization step, 5. drying step, 6. punching step, and 7. pressurization forming step. 1. In the crushing step, the carbon fiber is cut into a predetermined fiber length. 2. In the mixing step, the carbon fiber, phenolic resin, and aromatic polyamide fiber are placed in a container filled with water for dispersion and mixing. 3. In the papermaking step, the mixed liquid is papered in a papermaking frame. 4. In the dehydration and pressurization step, the mixed liquid in the copying frame is dehydrated, and the raw profile is formed by dehydration and pressurization. 5. In the drying step, the raw profile is dried. 6. In the punching step, the dried raw profile is punched by a Thomson knife in the desired shape, such as the shape of a plate or a tool. 7. In the pressurization and forming step, the moisture content of the raw profile after punching is adjusted, and the forming is completed by pressurization with a press machine. The materials of CFRP plates are phenolic resin, carbon fiber, and aromatic polyamide fiber.

The papermaking method in the papermaking step is a generally known method. The purpose of the papermaking step is to effectively fix the resin to the fiber. The details of the papermaking method are described in Japanese Patent Publication No. 2001-123386. Regarding the papermaking method, dispersed water in which heat-resistant fibers are dispersed is accumulated in a water storage tank having a plurality of drainage holes that can be opened and closed on the bottom surface, the drainage holes of the water storage tank are opened at the same time to discharge the dispersed water, and the dispersed water falling from the water storage tank is received by a papermaking tank arranged below the water storage tank, and water is pumped out from the papermaking tank, thereby scooping the heat-resistant fibers using a scooping net arranged in the papermaking tank.

The carbon fibers are recycled carbon fibers that are defective products in the production of carbon fibers before being spun and impregnated with resin. The manufacturing method of the CFRP plate of Example 1 is described in detail. 1. In the crushing step, the recycled carbon fibers are cut into fiber lengths of 10 mm and 15 mm. 2. In the mixing step, in a container, 5 wt% of aromatic polyamide fibers, 50 wt% of phenolic resin that is a thermosetting resin, and 22.5 wt% of carbon fibers with a fiber length of 10 mm and 22.5 wt% of carbon fibers with a fiber length of 15 mm are dispersed and mixed in a large amount of water in the container. 3. In the copying step, the mixed liquid is copied in a copying frame. 4. In the dehydration and pressurization step, the mixed liquid in the copying frame is dehydrated to form a blank profile. 5. In the drying step, the blank profile is dried at 80°C for 3 hours. 6. In the punching step, the blank profile is punched by a Thomson knife in the shape of the plate. 7. In the pressurization and forming step, pressurization and heating are performed. By drying, the moisture content of the blank profile is reduced to about 10%. The heating temperature is 140°C, and in order to obtain a formed product with a thickness of 5 mm, it is formed by pressing at a pressure of 150 tons for 5 minutes.

The experimental results of the bending strength of the CFRP plate of Example 1 are shown in FIG4. In FIG4, "10/50% + 15/50%" means that in the carbon fiber accounting for 45 wt% of the material of the CFRP plate of the phenolic resin, carbon fiber, and aromatic polyamide fiber, the carbon fiber with a fiber length of 10 mm and the carbon fiber with a fiber length of 15 mm are each 50 wt%. The maximum value of the bending strength of the CFRP plate of Example 1 is 672.16 MPa, which is a relatively large value. The average value of the bending strength with an N number of 40 is 547.01 MPa, and the CFRP plate can be used as a handheld tool.

As a comparative example, 5 wt% of aromatic polyamide fiber, 50 wt% of phenolic resin belonging to thermosetting resin, and 45 wt% of a carbon fiber with a fiber length of 9 mm were used as materials, and a CFRP plate of the same shape was manufactured by the same manufacturing method as Example 1. FIG3 shows the experimental results of the bending strength of the CFRP plate of the comparative example. It is generally believed that the bending strength of hand-held tools needs to be above 500 MPa, preferably above 550 MPa, and more preferably above 600 MPa. Regarding the CFRP plate of the comparative example, the average value of the bending strength with an N number of 40 is 479.03 MPa, which is not strong enough to be used as a hand-held tool.

FIG9 shows the test results of the bending strength of the CFRP plates divided by the fiber length of the carbon fibers. In FIG9, the CFRP plates A to D are made of two types of carbon fibers with different fiber lengths. Regarding the CFRP plates A to C, the proportions of carbon fibers with a fiber length of 10 mm and carbon fibers with a fiber length of 15 mm are different in the 45 wt% of carbon fibers that make up the materials of the CFRP plates (phenolic resin, carbon fibers, and aromatic polyamide fibers). The CFRP plate A has a carbon fiber with a fiber length of 10 mm set to 90 wt% and a carbon fiber with a fiber length of 15 mm set to 10 wt%. The CFRP plate of B has a carbon fiber with a fiber length of 10 mm set to 70 wt%, and a carbon fiber with a fiber length of 15 mm set to 30 wt%. The CFRP plate of C is the CFRP plate of the above-mentioned Example 1. Regarding the CFRP plate of D, among the carbon fibers accounting for 45 wt% of the material of the CFRP plate, the carbon fiber with a fiber length of 10 mm is set to 50 wt%, and the carbon fiber with a fiber length of 20 mm is set to 50 wt%. Compared with the CFRP plates of A to C, the maximum value of the bending strength of the CFRP plate of D is larger, but the average value of the bending strength when the N number is 40 is smaller.

In Figure 9, CFRP plates E to M are made of carbon fibers of one fiber length. Regarding the bending strength of the CFRP plates, the CFRP plates made of two types of carbon fibers of different fiber lengths tend to have greater bending strength than the CFRP plates made of carbon fibers of one fiber length.

Regarding the fiber length of carbon fiber, it is also believed that the strongest strength can be expected when it is less than 9 mm in the papermaking method, which is better. It was found that the bending strength of the CFRP plate made of carbon fiber with a fiber length of 9 mm (CFRP plate F in Figure 9) is about 450 MPa, which is less than 500 MPa and cannot be used, and it was found that carbon fiber with a fiber length of 10 mm to 15 mm can be used. By adjusting the length of the leftover carbon fiber that was considered unusable in the papermaking method, a bending strength of more than 550 MPa was successfully achieved. From the CFRP plate C in Figure 9 (of the carbon fibers that account for 45 wt% of the material of the CFRP plate, the carbon fibers with a fiber length of 10 mm are set to 50 wt%, and the carbon fibers with a fiber length of 15 mm are set to 50 wt%), it can be seen that the required strength can be achieved by using two types of carbon fibers with different fiber lengths. Furthermore, even carbon fibers with a fiber length of 10 mm to 15 mm, which are considered unusable, can achieve a bending strength of more than about 600 MPa by using the papermaking method.

<Example 2> As a CFRP plate, a wrench belonging to a hand tool was manufactured as shown in FIG8. The manufacturing method of the tool is as follows, that is, in the mixing step, 5 wt% of aromatic polyamide fiber, 50 wt% of phenol resin belonging to a thermosetting resin, and 22.5 wt% of carbon fiber with a fiber length of 10 mm and 22.5 wt% of carbon fiber with a fiber length of 15 mm are mixed in a container filled with water, and the materials are evenly dispersed and mixed in the container, and the mixture is made in a making frame, and the mixed liquid after making is dehydrated to form a plain profile. The thickness of the formed plain profile is 10 mm. 10 sheets of raw profiles are stacked to a thickness of 100 mm and pre-dried by, for example, natural drying to facilitate cutting with a Thomson knife. Afterwards, they are punched with a tool-shaped Thomson knife, the moisture content is adjusted, and hot-pressed at 180°C to form a wrench with a thickness of 7 mm and a diameter of 17 mm.

Regarding the manufacturing method of the wrench belonging to the tool of CFRP plate of Example 2, the contents after the mixing step are described in detail. Although the values vary depending on the production volume, this is to make it easier to understand the explanation of the copying method, and the situation of small-scale production will be described. 1. Store water in a bucket (container). (22.5 L (liters), 4 cups) 2. Add the aromatic polyamide fiber, phenolic resin, and carbon fiber materials into the bucket. (Except defoaming agent, dispersant, and flocculant) 3. Use a dissolver (mixer) to evenly disperse the materials in the water in the bucket to complete the dispersion of water. (4000 rpm, 5 minutes) 4. While manually stirring the water in the slurry bucket, add the dispersant and stir 20 times. 5. While manually stirring the water in the slurry bucket with the dispersant added, add the flocculant and stir about 10 times to complete the slurry. 6. Store 3. of the dispersed water about 10 cm below in the papermaking frame and add 5. of the slurry. 7. Extract water from the papermaking frame. 8. Use a vacuum pump or a ring blower to extract a certain amount of water from the papermaking sheet. 9. Take out the sheet from the papermaking frame and dehydrate it by applying pressure. (30 kg to 40 kg pressure per square centimeter, 3 minutes) 10. Punch the dehydrated sheet with a Thomson knife using a hydraulic cutter. (Hereinafter referred to as blanks rather than sheets) 11. Arrange the blanks in a dryer for drying. (Current conditions: 80°C × 4.5 hours) 12. Measure the weight of the dried blanks and classify them. 13. Combine the blanks classified by weight into the weight of the product. 14. Stack the combined blanks into several layers, heat and form them into a flat plate. (Pre-forming; current conditions: 100 kg pressure per square centimeter, 80°C × 1 minute) 15. Heat and form the blanks made into flat plates. (Current conditions: 1 t pressure per square centimeter, 180℃ x 1 minute per millimeter thickness) 16. Remove the burrs of the molded product taken out of the mold to complete the manufacturing.

The carbon fiber used here is recycled carbon fiber. Here, as an example, the dissolution method, which is a method for producing recycled carbon fiber, is described. The method for producing recycled carbon fiber by dissolution method is a well-known method. For example, Japanese Patent Laid-Open No. 2020-37638 discloses a resin dissolution device for the dissolution method. The resin dissolution device dissolves the resin material contained in the carbon fiber reinforced plastic. The resin dissolution device is equipped with a dissolution tank, a gas introduction part, and a guide wall. With respect to the dissolution tank, a dissolving liquid containing sulfuric acid and the carbon fiber reinforced plastic are added while managing the temperature and concentration. The gas introduction part is arranged on the lower surface of the dissolution tank, and introduces a foaming gas into the processing space provided in the dissolution tank to generate bubbles. The guide wall is extended upward in the processing space to surround the gas introduction part, and guides the dissolving liquid that rises with the bubbles. The carbon fiber reinforced plastic is put into the outer side of the guide wall, and a through hole is set near the lower surface of the dissolving tank of the guide wall. The through hole is used to prevent the carbon fiber contained in the carbon fiber reinforced plastic from invading the inner side of the guide wall, and to make the dissolving liquid convect in the processing space. The resin dissolving device can produce recycled carbon fibers.

FIG5 is the performance test result of the wrench belonging to the CFRP plate tool of Example 2 in a public laboratory, and the remarks column indicates the evaluation basis. According to the performance test result, the CFRP plate tool of Example 1 is a qualified product in terms of tool strength, tightening torque, impact test, and live test, and can be used as a hand tool. FIG6 and FIG7 are diagrams showing the torque test of the wrench of Example 2. The general tightening torque of the standard torque table is 42 N·m when the nominal diameter is M12. In contrast, the CFRP plate tool of Example 1 can reach 55 N·m.

The wrench of Example 2 is 7 mm thick. When the thickness of the tool is 8 mm to 10 mm, the same plain profile as that of Example 2 is overlapped to a thickness of about 100 mm and press-formed to a thickness of 8 mm to 10 mm.

CFRP plate tools can provide hand tools with roughly the same bending strength as iron hand tools, and have 1/4 to 1/7 of their weight, which is beneficial in terms of explosion protection and ensuring the safety of high-altitude operations.

When a 3 mm thick CFRP plate made of recycled carbon fiber was compared with a 1 mm thick SUS (stainless steel) plate, the bending strength was 502 MPa vs. 578 MPa, and the tensile load strength was 6433 N vs. 6400 N, confirming that they have roughly the same strength. By combining waste materials, thermosetting resins, and papermaking methods, a hand tool with satisfactory strength and explosion-proof performance was realized for the first time in the world.

A wrench is shown as the tool for the CFRP plate, but a hand tool such as a wrench can be formed by changing the shape of the die cutter and adjusting the pressing pressure and time according to the size of the hand tool.

The present invention is extremely beneficial because it realizes the lightweight and explosion-proof function of CFRP plates through the papermaking method and thermosetting resin. In addition, it can also reuse carbon fibers and does not require the melting process at a temperature of thousands of degrees required for obtaining iron, stainless steel and other tools, thus making a greater contribution to the reduction of carbon dioxide.

It is known that when working at heights, tools are held at the waist, which may cause waist pain due to their weight. However, if the present invention is used for tools, it is expected to alleviate waist pain due to their light weight, and it will not cause serious accidents due to the falling of tools. Furthermore, if the present invention is used for tools, it will not rust like metal, so it can also be expected to be used in the food industry.

According to the present invention, the carbon fiber most suitable for manufacturing CFRP plates by using a mixture of thermosetting resin and carbon fiber through a papermaking method is disclosed. A method for manufacturing CFRP plates using recycled carbon fibers or carbon fiber waste used in aircraft, etc. (a large amount of waste that is difficult to utilize is generated before the carbon fibers are impregnated with resin, and there is no method for utilizing it, with an annual output of more than 70 tons) is established.

Since the final use of recycled carbon fiber is non-woven cushioning materials and sound insulation materials, the strength measurement results of the molded products obtained by the papermaking method show that the strength is insufficient. The present invention has found a commercially available carbon fiber that solves the problem of insufficient strength in the papermaking method, and has determined a CFRP plate with satisfactory strength and a manufacturing method thereof. In particular, the recycled carbon fiber material used has a lower raw material price than the product price, and can be manufactured more cheaply than existing competitive products. (Industrial Applicability)

The present invention is extremely excellent as an environmental countermeasure, and has significant effects such as explosion-proof, fire-proof, and lightweight. The present invention is a plate for cutting processing made of thick CFRP that can be processed with high precision by super-hard cutting tools in the same way as metal, and can be used as a base for electronic components, etc. The present invention can be used for connector components, end effector components of insertion robots, shims (spacers) connecting the robot body and working claws, etc. In addition, in the case of tools, etc., it can be expected to be widely used in industries such as the gasoline chemical industry, oil and gas industry, explosives manufacturing plants, shipyards, aviation industry, medical industry, and food industry for machine maintenance. Furthermore, it can be expected to replace light-weight and strong gears and robot arms that have traditionally relied on metal.

FIG. 1 is a perspective view of a CFRP plate of Example 1. FIG. 2 is a flow chart showing a method for manufacturing a CFRP plate of Example 1. FIG. 3 is a table showing test results of bending strength of a tool for a CFRP plate made of carbon fiber with a fiber length of 9 mm as a comparative example. FIG. 4 is a table showing test results of bending strength of a tool for a CFRP plate of Example 1. FIG. 5 is a table showing test results of performance evaluation of a tool for a CFRP plate of Example 2. FIG. 6 is an enlarged photograph of a main part of a torque measurement test of a tool for a CFRP plate of Example 2. FIG. 7 is an overall photograph of a main part of a torque measurement test of a tool for a CFRP plate of Example 2. FIG. 8 is a perspective view of a tool for a CFRP plate of Example 2. Figure 9 is a table showing the test results of the bending strength of carbon fibers divided by fiber length.

Claims (4)

A carbon fiber reinforced plastic sheet is formed by using a sheet as a plain profile, wherein the sheet comprises: a phenolic resin belonging to a thermosetting resin, one or more carbon fibers with a fiber length ranging from 10 mm to 15 mm, and aromatic polyamide fibers belonging to an adhesive; the bending strength of the carbon fiber reinforced plastic sheet is above 500 MPa. As in claim 1, the carbon fiber reinforced plastic sheet, wherein the carbon fiber is of two types, one having a fiber length of 10 mm and the other having a fiber length of 15 mm. A method for manufacturing a carbon fiber reinforced plastic sheet, which is to manufacture the carbon fiber reinforced plastic sheet of claim 1 or 2, wherein the material is a phenolic resin belonging to a thermosetting resin, one or more carbon fibers with a fiber length ranging from 10 mm to 15 mm, and aromatic polyamide fibers. The materials are mixed in a ratio of 50 wt % of the phenolic resin, 45 wt % of the carbon fibers, and 10 wt % of the aromatic polyamide fibers. 5wt% of polyamide fiber is dispersed and mixed in water in a container, and the paper is made in a papermaking frame. The mixed liquid in the papermaking frame is dehydrated in the frame, and the residue after dehydration is dried to form a blank profile. The blank profile is punched by a Thomson knife, and the blank profile is dried after punching, and is heated and formed by a press. As in claim 3, the manufacturing method of carbon fiber reinforced plastic sheet, wherein the carbon fiber is 22.5wt% carbon fiber with a fiber length of 10mm and 22.5wt% carbon fiber with a fiber length of 15mm.