JP6700049B2 - Carbon fiber sheet material, prepreg, laminated body, molded body and manufacturing method thereof - Google Patents

Description

  The present invention relates to a carbon fiber sheet material, a prepreg, a laminated body, a molded body, and a method for producing them.

  A fiber reinforced sheet material and a fiber reinforced resin molded product obtained by laminating the same are used in various fields such as vehicles and aircraft. In particular, fiber reinforced plastic (FRP) realizes excellent strength that cannot be achieved by a single plastic, because the plastic is reinforced by the embedded reinforcing fibers. Although glass fibers are mainly used as the reinforcing fibers used in FRP, metal fibers such as aluminum fibers and stainless fibers, organic fibers such as aramid fibers and PBO fibers, and inorganic fibers such as silicon carbide fibers are also used. used. Further, in recent years, inorganic fibers such as carbon fibers have come to be used because they have extremely excellent physical properties.

  Carbon Fiber Reinforced Plastics (CFRP), which uses carbon fibers as high-strength fibers, uses thermosetting resin as a matrix (base material) resin and stacks multiple prepregs into a preform, which is pressed. It is made by molding. The prepreg is manufactured by impregnating a thermosetting resin into a high-strength fiber base material obtained by processing carbon fibers into a sheet. The high-strength fiber base material is manufactured by arranging continuous or discontinuous high-strength fibers or by textile processing (see Patent Document 1).

Japanese Patent No. 5309563

  The carbon fiber reinforced thermoplastic resin molded body disclosed in Patent Document 1 uses single fiber carbon fibers. According to the document, the carbon fibers 901 are dispersed in the thermoplastic resin 930 in a single fiber state, as shown in the schematic view of the cut surface of the carbon fiber reinforced thermoplastic resin molded body 900 shown in FIG. It is said to be preferable. On the other hand, if the carbon fibers are present in a bundle, a resin-rich portion composed only of the resin is generated in the gap between the bundles, and the mechanical properties may be deteriorated. Further, when the carbon fibers are present in a bundled state, the thermoplastic resin cannot be impregnated into the carbon fiber bundle to form an unimpregnated portion, and the mechanical properties may be deteriorated, which is described in the document.

  However, as a result of a detailed verification test conducted by the inventors of the present application, it was found that the strength is rather decreased when the single-fiber carbon fibers are uniformly dispersed as shown in FIG. As a result of studying the reason, when the carbon fibers 901 are dispersed in a single fiber shape as shown in FIG. 1, a space is generated around each carbon fiber. Therefore, the thermoplastic resin which is the base material for filling the space is formed. It is presumed that a large amount of 930 is required and the amount of resin per unit volume increases, resulting in a relative decrease in the ratio of carbon fibers and an inability to improve strength.

  The present invention has been made on the basis of such findings, and one of the objects thereof is to provide a carbon fiber sheet material, a prepreg, a laminate, a molded body having a further improved strength and a method for producing them. Especially.

Means for Solving the Problems and Effects of the Invention

The carbon fiber sheet material according to the first aspect of the present invention is a carbon fiber sheet material including a plurality of carbon fibers and a binder resin that binds the carbon fibers, wherein the carbon fibers have a length direction. In the cross-sectional view, the particles are dispersed in a bundled state, and the air permeability measured by stacking three carbon fiber sheet materials can be 60 to 150 cm ³ /cm ² ·sec.

  Moreover, according to the carbon fiber sheet material concerning the 2nd side surface of this invention, it is a carbon fiber sheet material provided with several carbon fiber and the binder resin which couple|bonds the said carbon fiber, Comprising: The said carbon fiber is long. The carbon fibers are dispersed in a bundle in a cross-sectional view in the vertical direction, and the average thickness when a pressure of 50 kPa is applied to the carbon fiber sheet material is 10 to 400 with respect to the average diameter of the carbon fibers. It can be doubled.

  Furthermore, with the carbon fiber sheet material according to the third aspect of the present invention, the carbon fibers can be brought into a state in which they are converged in an unopened state.

  Furthermore, according to the carbon fiber sheet material of the fourth aspect of the present invention, the carbon fibers can be discontinuous carbon fibers.

  Furthermore, according to the carbon fiber sheet material of the fifth aspect of the present invention, the carbon fibers can have a weight average fiber length of 0.2 mm to 26 mm.

  Furthermore, according to the carbon fiber sheet material of the sixth aspect of the present invention, the carbon fibers can have irregularities on the surface. As a result, the apparent surface area of the carbon fiber is increased and the interfacial adhesion area with the matrix resin is increased, whereby the strength of the carbon fiber reinforced resin molded product can be improved.

  Furthermore, according to the carbon fiber sheet material of the seventh aspect of the present invention, the carbon fiber can have a fracture surface on the surface.

  Furthermore, according to the carbon fiber sheet material according to the eighth aspect of the present invention, the carbon fiber is recycled in a state where the matrix resin and/or the sizing agent remain and/or a part thereof is carbonized. It can be carbon fiber. With the above configuration, when the carbon fiber is recovered from the waste material of CFRP or the like, the carbon fiber can be effectively utilized even when the residual resin component remains.

  Furthermore, with the prepreg according to the ninth aspect of the present invention, these carbon fiber sheet materials can be impregnated with a thermosetting resin that serves as a matrix resin.

Furthermore, the prepreg according to the tenth aspect of the present invention is a prepreg obtained by mixing a plurality of carbon fibers, a binder resin that binds the carbon fibers, and a thermoplastic resin fiber, wherein the carbon The fibers are dispersed in the binder resin in a state of being bundled in a cross-sectional view in the lengthwise direction, and the air permeability measured by stacking three prepregs is 20 to 100 cm ³ /cm ² ·sec. Can be

  Furthermore, the laminate according to the eleventh aspect of the present invention can be configured by laminating these prepregs.

  Furthermore, according to the molded product of the twelfth aspect of the present invention, these prepregs can be formed by thermocompression molding.

Furthermore, according to the method for producing a carbon fiber sheet material according to the thirteenth aspect of the present invention, a plurality of carbon fibers are mixed with a binder resin that binds the carbon fibers, and the carbon fibers are lengthwise. Is a method for manufacturing a carbon fiber sheet material that is made into a bundle in a cross-sectional view, and has an air permeability of 60 to 150 cm ³ /cm ² ·sec measured by stacking three carbon fiber sheet materials. Can be

  Furthermore, according to the method for producing a carbon fiber sheet material according to the fourteenth aspect of the present invention, a plurality of carbon fibers are mixed with a binder resin that binds the carbon fibers, and the carbon fibers are lengthwise. Is a method for producing a carbon fiber sheet material which is made into a bundle in a cross-sectional view in a cross-sectional view, wherein an average thickness when a pressure of 50 kPa is applied to the carbon fiber material is defined as an average diameter of the carbon fibers. It can be increased by 10 to 400 times.

Furthermore, according to the method for producing a molded body according to the fifteenth aspect of the present invention, a plurality of carbon fibers are mixed with a binder resin that binds the carbon fibers, and the carbon fibers have a cross section in the longitudinal direction. A step of producing a carbon fiber sheet material by papermaking in a state of being converged into a bundle in view, a step of impregnating the carbon fiber sheet material with an uncured thermosetting resin to produce a prepreg, and the prepreg A method for producing a molded article, comprising the step of curing a thermosetting resin to produce a molded article, wherein the air permeability measured by stacking three carbon fiber sheet materials is 60 to 150 cm ³ /cm ^2.・It can be sec.

  Furthermore, according to the method for producing a molded body according to the sixteenth aspect of the present invention, a plurality of carbon fibers are mixed with a binder resin that binds the carbon fibers, and the carbon fibers have a cross section in the longitudinal direction. A step of producing a carbon fiber sheet material by papermaking in a state of being converged into a bundle in view, a step of impregnating the carbon fiber sheet material with an uncured thermosetting resin to produce a prepreg, and the prepreg A method for producing a molded body, comprising a step of curing a thermosetting resin to produce a molded body, wherein an average thickness when a pressure of 50 kPa is applied to the carbon fiber sheet material, It can be 10 to 400 times the average diameter.

Furthermore, according to the method for producing a molded body according to the seventeenth aspect of the present invention, a plurality of carbon fibers, a binder resin that binds the carbon fibers, and a thermoplastic resin fiber are mixed and made into a prepreg. A method of manufacturing a molded body, comprising: a step and a step of thermoforming the prepreg to produce a molded body, wherein an air permeability measured by stacking three prepregs is 20 to 100 cm ³ /cm ^2.・It can be sec.

  Furthermore, according to the method for producing a molded body according to the eighteenth aspect of the present invention, a plurality of carbon fibers, a binder resin that binds the carbon fibers, and a thermoplastic resin fiber are mixed to prepare a prepreg. A method of manufacturing a molded body, which comprises a step and a step of thermoforming the prepreg to form a molded body, wherein an average thickness when a pressure of 50 kPa is applied to the prepreg is equal to that of the carbon fiber. It can be 10 to 400 times the average diameter.

FIG. 3 is a schematic cross-sectional view of a carbon fiber reinforced thermoplastic resin molded body in which carbon fibers are dispersed in a thermoplastic resin in a single fiber state. It is a schematic cross section of the carbon fiber sheet material concerning one embodiment of the present invention. 1 is a photograph showing a carbon fiber sheet material according to Example 1. 5 is a photograph showing a carbon fiber sheet material according to Comparative Example 1. It is a SEM photograph showing carbon fiber of virgin. It is a SEM photograph which shows the carbon fiber which provided the unevenness|corrugation on the surface.

  Hereinafter, embodiments of the present invention will be described. However, the following embodiments and examples exemplify a carbon fiber sheet material and a manufacturing method thereof for embodying the technical idea of the present invention, and the present invention is a carbon fiber sheet material and a manufacturing method thereof. The method is not limited to the following. In addition, the present specification does not specify the members described in the claims to the members of the embodiments. Unless otherwise specified, the dimensions, materials, shapes, relative positions, etc. of the components described in the embodiments are not intended to limit the scope of the present invention thereto, but are merely descriptions. It's just an example. The sizes and positional relationships of members shown in the drawings may be exaggerated for clarity of explanation. Further, in the following description, the same names and reference numerals indicate the same or similar members, and detailed description thereof will be appropriately omitted. Further, each element constituting the present invention may be configured such that a plurality of elements are configured by the same member and one member also serves as a plurality of elements, or conversely, the function of one member is performed by a plurality of members. It can be shared and realized.

In the present specification, the term “sheet material” is used to mean a single sheet material, as well as a laminated body in which a plurality of these are laminated, a mat-like or lump-like one.
(Binder resin)

As the binder resin, polyvinyl alcohol resin (PVA) or thermoplastic resin can be used. As the thermoplastic resin, for example, polyester, polypropylene, polyethylene, polyamide, polyvinyl acetate, polyphenylene sulfide can be used. In particular, it is preferably made of polyvinyl alcohol resin. As a result, the binder fixes the fibers by point-bonding the fibers, and the drape property can be maintained on the sheet.
(Method for manufacturing carbon fiber sheet material)

Next, the manufacturing method will be described. First, a method for manufacturing a carbon fiber sheet material will be described.
(Papermaking process)

First, a carbon fiber is mixed with a binder resin to prepare a carbon fiber sheet material. In the papermaking process, in order to make the carbon fiber bundles converge without being dispersed, the concentration at the time of papermaking is increased. For example, the concentration is adjusted to 0.1 to 0.3%. Next, a resin called a sizing agent is attached to the surface of the carbon fiber.
(Resin impregnation process)

Next, to obtain a prepreg, the carbon fiber sheet material is impregnated with an uncured thermosetting resin. Here, a method of thermally transferring an uncured thermosetting resin sheet, a method of impregnating a liquid thermosetting resin, or the like can be used. As the thermosetting resin, for example, epoxy resin, phenol resin, melamine resin, unsaturated polyester resin or the like can be used.
(Molding process)

Further, in order to produce a molded body, the thermosetting resin of the prepreg is cured to produce a molded body. In the molding step, one or more prepregs obtained in the resin impregnation step are laminated to obtain a preform, and the preform is heated and pressed to produce a carbon fiber reinforced resin molded body. The cured thermosetting resin becomes the matrix resin.
(Thermoplastic resin fiber)

  Further, instead of the thermosetting resin, a thermoplastic resin fiber may be used. In this case, the papermaking process and the resin impregnation process can be performed simultaneously. That is, in addition to the carbon fiber and the binder resin, the thermoplastic resin fiber can be mixed and produced at the same time to produce the prepreg. One or more of the obtained prepregs are laminated in the same manner as described above, and a carbon fiber reinforced resin molding can be obtained through a molding step of hot pressing. This thermoplastic resin fiber becomes a matrix resin after thermocompression molding. Examples of the thermoplastic resin that can be used include polyester, polypropylene, polyethylene, polyamide (nylon), polycarbonate, polystyrene acrylonitrile-butadiene-styrene resin (ABS resin), polyvinyl chloride resin, and polyphenylene sulfide.

  Carbon fibers of 10 to 60% by weight and thermoplastic resin fibers of 40 to 90% by weight are mixed and made into paper. Particularly, it is preferable that the carbon fiber content is 40% by weight or more. When the monofilament-like carbon fibers are uniformly dispersed, a space is generated around each carbon fiber. Therefore, a large amount of resin as a base material is required to fill this space. Therefore, when the carbon fiber ratio is high (for example, 40% by weight or more), the space generated around the carbon fiber cannot be filled with the resin and the space (void) remains, so that the strength of the carbon fiber reinforced resin molded body is increased. descend. In comparison with this, in the present invention, it becomes possible to reduce the space generated around each carbon fiber by converging the carbon fibers into a bundle, and as a result, increase the carbon fiber ratio and reduce the space even with a small resin ratio. Since the carbon fiber reinforced resin molded body can be produced without generating much (void), the molded body has high strength without lowering the strength.

  In the resin impregnation step, the uncured thermosetting resin sheet is laminated on the surface of the fiber base material and heated to melt the thermosetting resin sheet to form the uncured thermosetting resin into fibers. The interstices of the base material can be impregnated, or the surface of the fibrous base material can be impregnated with a liquid thermosetting resin in an uncured state to impregnate the interstices of the fibrous base material.

  In the molding process, one or more prepregs are laminated, heated and pressed to soften the resin contained in the prepreg, and then cured (solidified in the case of a thermoplastic resin) to form a carbon fiber reinforced fat molded body. To do.

  Although Patent Document 1 discloses a papermaking process, it is a batch method and not a continuous method. On the other hand, according to the present embodiment, continuous papermaking is possible, and in the case of mixed papermaking with thermoplastic resin fibers, a prepreg can be prepared in a one-step process and is excellent in productivity.

  As shown in the schematic cross-sectional view of FIG. 2, the carbon fiber sheet material 100 according to the present embodiment has a carbon fiber bundle 10 that is rather converged rather than a single fiber shape in which carbon fibers are completely opened. To do. By doing so, as in the state where the carbon fibers 901 are uniformly dispersed in a single fiber shape as shown in FIG. 1, a space is created around each carbon fiber, and the matrix resin is used to fill this space. It is possible to increase the fiber volume content as a result by suppressing the situation of being filled and reducing the amount of the required matrix resin 30. Here, the carbon fiber bundled in a bundle is a concept of a single fiber, and refers to a carbon fiber in which a plurality of carbon fibers are bundled. Examples of the bundle-shaped carbon fibers include those in which the fiber bundle is in an unopened state, and carbon fibers that have been once opened are aggregated again to form a bundle. Note that it is not necessary to make all the carbon fibers into a carbon fiber bundle as shown in FIG. 2, and the carbon fiber bundle 10 converged into a bundle is more dominant than the carbon fiber 20 having a single fiber shape. By forming the bundle to have a high ratio, the strength can be improved.

As an index showing the state in which the carbon fibers are present in a bundle form in the sheet material, parameters such as air permeability, translucency, and thickness of the carbon fiber sheet material under a constant pressure can be expressed. That is, when the air permeability and the translucency are high, it is found that the bundled carbon fibers are more dominant than the single fibers.
(Thickness measurement)

  Here, a wet type nonwoven fabric was experimentally manufactured as a carbon fiber sheet material according to Example 1 and Comparative Example 1 and its average thickness was measured. First, in order to prepare a wet non-woven fabric, 1 L of water was put into a disintegrator, raw material fibers were added, and the number of revolutions and screw shapes were made uniform and stirred under the same conditions for the same time (20 sec). The prepared slurry was diluted to 20 L, uniformly dispersed, and dehydrated on a wire mesh using a square sheet machine (Kumagaya Riki Kogyo Co., Ltd.) to form a sheet having a size of 250×250 mm, and then dried to obtain a nonwoven fabric. did.

  The raw material carbon fiber used had a fiber length of 6 mm and a fiber diameter of 7 μm. In Comparative Example 1, no sizing agent was used, and the conditions were such that dispersion was easy. On the other hand, in Example 1, the presence of the nylon sizing agent was adjusted so that the carbon fibers remained in a bundle state under the condition that it was difficult to disperse. In addition, a nylon 6 fiber having a fineness of 1.1 dtex and a fiber length of 6 mm and a polyvinyl alcohol fiber having a fineness of 1.1 dtex and a fiber length of 3 mm were used.

  A photograph of the carbon fiber sheet material according to Example 1 is shown in FIG. 3, and a photograph of the carbon fiber sheet material according to Comparative Example 1 is shown in FIG.

In this way, a prepreg, which is a precursor of the carbon fiber reinforced resin molding, was produced. The blending ratio was 40.2% by weight of carbon fiber, 56.9% of nylon 6 fiber, and 2.9% of polyvinyl alcohol fiber. A basis weight of 100 g/m ² was obtained.

On the other hand, a carbon fiber sheet was prepared for comparison with a CFRTP (thermoplastic carbon fiber reinforced resin molded product) prepreg. The composition of the carbon fiber sheet was 95% carbon fiber and 5% polyvinyl alcohol fiber to obtain a carbon fiber sheet having a basis weight of 40 g/m ² .

  The thickness of the CFRTP prepreg and the carbon fiber sheet thus obtained was measured. Here, as a measuring method, several sheets were stacked and the measurement was performed using a paper thickness measuring instrument (TH-101 manufactured by Tester Sangyo Co., Ltd.). As the measurement conditions, a stroke of 10 mm, a pressure of 50±5 kPa, and a pressure surface dimension of φ14.3 mm were measured at 8 points. As a measurement procedure, the dial gauge was set to zero, the lever was lowered, the test piece was set between the probe and the sample stand, and then the lever was gently released, and when the value became stable, the value was read. Also, three CFRTP prepregs and carbon fiber sheets were stacked. Table 1 shows the measurement results of the CFRTP prepreg, and Table 2 shows the measurement results of the carbon fiber sheet.

From the above measurement results, it was shown that the smaller the value of the thickness measurement, the thinner, that is, the density was likely to increase, and the superiority of the present invention was confirmed.
(Measurement of breathability)

  Next, the air permeability was measured for the CFRTP prepreg and the carbon fiber sheet prepared under the same conditions. The measurement method was performed by stacking several sheets and using a Frazier type air permeability tester (AP-200KZ manufactured by Daiei Kagaku Seiki Co., Ltd.). The conditions and procedure of the comparative test were in accordance with JIS L-1096 (breathability A method, Frazier type method). However, since the air permeability was too low to measure, measurement was performed by stacking three samples. Table 3 shows the measurement results of the CFRTP prepreg, and Table 4 shows the measurement results of the carbon fiber nonwoven fabric.

From the above results, the higher the value of the air permeability, the easier the resin to flow, that is, the more excellent the fluidity is, which contributes to the improvement of the strength of the carbon fiber resin molded body, so that the superiority of the present invention was confirmed. The air permeability of the prepreg is preferably ²⁰ to 100 cm ³ /cm ² ·sec as a value measured by stacking three sheets. The air permeability of the carbon fiber sheet material is preferably 60 to 150 cm ³ /cm ² ·sec as a value measured by stacking three sheets.
(Hot press molding)

  Further, the above CFRTP prepreg was formed into a molded body by heat and cool press molding. Specifically, 25 sheets of CFRTP prepreg are set in a mold (280×250 mm) preheated to 250° C., preheated for 1 minute, pressed at a pressure of 10 MPa, cooled as it is, and at a temperature of 80° C. or less. It was taken out to obtain a molded plate. Tensile and bending strength tests were carried out as the physical properties of the CFRTP molded plate according to Example 1 and Comparative Example 1 thus obtained. The results are shown in Table 5 below.

As shown in Table 5, the molded body according to Example 1 exhibited more excellent tensile strength, tensile elastic modulus, and bending strength than Comparative Example 1, and it was confirmed that the strength was improved.
(Asperity of carbon fiber surface)

  Furthermore, it is also preferable to provide irregularities on the surface of the carbon fiber. By doing so, the surface area of the carbon fibers can be increased and the interfacial adhesion area with the matrix resin can be increased, which can contribute to the improvement of strength. Moreover, it is preferable that the unevenness includes a fractured surface. This makes it possible to discontinue the joint portion and improve the mechanical joint strength. Further, by forming such irregularities with a resin, the same adhesive strength as the matrix resin can be obtained. FIG. 5 shows an SEM photograph of ordinary carbon fiber and FIG. 6 shows an SEM photograph of carbon fiber having irregularities. As seen in these SEM photographs, by forming discontinuous irregularities on the surface of the carbon fiber, physical engagement can be easily obtained at the bonding interface with the matrix resin, which is also structurally advantageous.

Such unevenness is provided on the virgin carbon fiber by surface treatment or the like. Alternatively, when the carbon fibers are recovered (recycled carbon fibers) from the waste material of the carbon fiber reinforced plastic, the matrix resin or the sizing agent remaining on the surface may be used. The unevenness is formed by the resin remaining at the time of heating for recovery. FIG. 6 shows a recycled carbon fiber. By using such a recycled carbon fiber, it is possible to obtain a molded product which is advantageous in terms of cost, environmentally friendly in terms of resource recycling, and also advantageous in strength. Obtainable.
(Recycled carbon fiber)

  Recycled carbon fiber is obtained by recovering carbon fiber from CFRP waste materials and the like. Using this recycled carbon fiber, a carbon fiber sheet material and a carbon fiber reinforced resin molding are obtained again. When obtaining recycled carbon fibers, the residual resin content (sizing, matrix resin) is intentionally left by adjusting the conditions (for example, firing temperature). This makes it easy to obtain a bundle of carbon fibers even when dispersed in water.

  A carbon fiber sheet material made from recycled carbon fiber was prepared and its dispersibility was evaluated. A carbon fiber sheet material made from virgin carbon fiber was prepared as Comparative Example 2 for comparison with recycled carbon fiber. The carbon fiber of the virgin product was obtained by cutting the fiber length to 6 mm. From the experimental results, it was found that the carbon fiber sheet material prepared under normal firing conditions was not sufficiently converged due to the dispersion of the carbon fibers.

  Next, a carbon fiber sheet material having a firing temperature higher than that of Comparative Example 3 was produced as Example 2. As a result, it was found that the dispersibility was improved and a certain degree of convergence was obtained.

  According to the carbon fiber sheet material, the prepreg, the laminate, the molded body and the manufacturing method thereof according to the present invention, CFRTP (Carbon Fiber Reinforced Thermoplastics) and CFRTS (Carbon Fiber Reinforced Thermosets) It can be suitably used as a thermosetting resin). In addition to the prepreg which is a precursor, it can be suitably used for various products obtained from the prepreg. For example, it can be suitably used as an electromagnetic wave absorbing and shielding material, a heat insulating material, an electrode material and the like. Further, as the carbon fiber reinforced resin molded body, for example, constituent materials for vehicles (for example, automobiles, bicycles, trains, aircraft, rockets, elevators, etc.), constituent materials for electronic and electric parts (for example, personal computer/portable housings, etc.) It can be preferably used in construction, materials for civil engineering structures, furniture and the like.

100... Carbon fiber sheet material 1... Carbon fiber 10... Carbon fiber bundle 20... Single fibrous carbon fiber 30... Binder resin 900... Carbon fiber reinforced thermoplastic resin molding 901... Carbon fiber 930... Thermoplastic resin

Claims (18)

Multiple carbon fibers,
A carbon fiber sheet material comprising a binder resin for binding the carbon fibers,
The carbon fibers are dispersed in a bundled state in a cross-sectional view with respect to the length direction,
A carbon fiber sheet material having an air permeability of 60 to 150 cm ³ /cm ² ·sec measured by stacking ^three carbon fiber sheet materials. Multiple carbon fibers,
A carbon fiber sheet material comprising a binder resin for binding the carbon fibers,
The carbon fibers are dispersed in a bundled state in a cross-sectional view with respect to the length direction,
A carbon fiber sheet material having an average thickness of 10 to 400 times the average diameter of the carbon fiber when a pressure of 50 kPa is applied to the carbon fiber sheet material. The carbon fiber sheet material according to claim 1 or 2,
A carbon fiber sheet material obtained by bundling the carbon fibers in an unopened state. The carbon fiber sheet material according to any one of claims 1 to 3,
A carbon fiber sheet material, wherein the carbon fiber is a discontinuous carbon fiber. The carbon fiber sheet material according to claim 4,
A carbon fiber sheet material in which the carbon fiber has a weight average fiber length of 0.2 mm to 26 mm. The carbon fiber sheet material according to any one of claims 1 to 5,
A carbon fiber sheet material in which the carbon fibers have irregularities on the surface. The carbon fiber sheet material according to any one of claims 1 to 6,
A carbon fiber sheet material, wherein the carbon fiber has a fracture surface on the surface. The carbon fiber sheet material according to any one of claims 1 to 7,
A carbon fiber sheet material, wherein the carbon fiber is a carbon fiber recycled in a state where a matrix resin and/or a sizing agent remains and/or a part thereof is carbonized.   A prepreg obtained by impregnating the carbon fiber sheet material according to any one of claims 1 to 8 with a thermosetting resin serving as a matrix resin. A prepreg obtained by mixing a plurality of carbon fibers, a binder resin that binds the carbon fibers, and a thermoplastic resin fiber,
The carbon fibers are dispersed in the binder resin in a state of being bundled in a cross-sectional view with respect to the length direction,
A prepreg having an air permeability of 20 to 100 cm ³ /cm ² ·sec measured by stacking 3 of the above prepregs.   A laminate obtained by laminating the prepreg according to claim 9 or 10. A molded body obtained by thermocompression molding the prepreg according to claim 9 or 10.
A method for producing a carbon fiber sheet material, which comprises mixing a plurality of carbon fibers into a binder resin that binds the carbon fibers, and making the carbon fibers in a bundle in a cross-sectional view in the length direction. hand,
A method for producing a carbon fiber sheet material, wherein the air permeability measured by stacking three carbon fiber sheet materials is 60 to 150 cm ³ /cm ² ·sec. A method for producing a carbon fiber sheet material, which comprises mixing a plurality of carbon fibers into a binder resin that binds the carbon fibers, and making the carbon fibers in a bundle in a cross-sectional view in the length direction. hand,
The method for producing a carbon fiber sheet material, wherein the average thickness when a pressure of 50 kPa is applied to the carbon fiber sheet material is 10 to 400 times the average diameter of the carbon fibers. A step of preparing a carbon fiber sheet material by mixing a plurality of carbon fibers into a binder resin that binds the carbon fibers, and paper-making the carbon fibers in a bundled state in a cross-sectional view in the length direction. When,
A step of making a prepreg by impregnating an uncured thermosetting resin into the carbon fiber sheet material;
A method of manufacturing a molded body, comprising a step of curing a thermosetting resin of the prepreg to prepare a molded body,
A method for producing a molded product, wherein the air permeability measured by stacking three carbon fiber sheet materials is 60 to 150 cm ³ /cm ² ·sec. A step of preparing a carbon fiber sheet material by mixing a plurality of carbon fibers with a binder resin that binds the carbon fibers, and paper-making the carbon fibers in a bundled state in a cross-sectional view in the length direction. When,
A step of making a prepreg by impregnating an uncured thermosetting resin into the carbon fiber sheet material;
A method of manufacturing a molded body, comprising a step of curing a thermosetting resin of the prepreg to prepare a molded body,
A method for producing a molded body, wherein an average thickness when a pressure of 50 kPa is applied to the carbon fiber sheet material is 10 to 400 times the average diameter of the carbon fiber. A plurality of carbon fibers, a binder resin that binds the carbon fibers, and a step of producing a prepreg by mixing thermoplastic resin fibers
A method for producing a molded body, which comprises a step of thermoforming the prepreg to produce a molded body,
A method for producing a molded product, wherein the air permeability measured by stacking three prepregs is 20 to 100 cm ³ /cm ² ·sec. A plurality of carbon fibers, a binder resin for binding the carbon fibers, a step of preparing a prepreg by mixing thermoplastic resin fibers,
A method for producing a molded body, which comprises a step of thermoforming the prepreg to produce a molded body,
The method for producing a molded body, wherein the average thickness when a pressure of 50 kPa is applied to the prepreg is 10 to 400 times the average diameter of the carbon fiber.