JP2016203397A - Method for producing prepreg - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method for producing a prepreg by a dry method which can raise a temperature even of a resin composition having high viscosity to a temperature capable of being impregnated in a short time.SOLUTION: The temperature of a resin composition can be instantly raised to a temperature capable of being impregnated by applying ultrasonic oscillation to the resin composition with the use of a resin impregnation apparatus having a heating section having an ultrasonic oscillator, an ultrasonic vibrator connected to the ultrasonic oscillator, and an ultrasonic horn mounted on the ultrasonic vibrator, and an impregnation section for nipping and compressing a base material-resin laminate in its thickness direction.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a method for producing a prepreg. In particular, the present invention relates to a method for producing a prepreg in which a layer of a resin composition is laminated on at least one surface of a fiber reinforced substrate, and heated and pressed to impregnate the resin composition in the fiber reinforced substrate.

  Fiber reinforced composite materials composed of reinforced fibers and resins are widely applied to aircraft, sports / leisure and general industries due to their features such as light weight, high strength, and high elastic modulus. This fiber-reinforced composite material is often manufactured via a prepreg formed by integrating reinforcing fibers and a resin.

  The prepreg is composed of a fiber reinforced base material composed of reinforcing fibers and a resin composition impregnated in the fiber reinforced base material. As a method for producing such a prepreg, a method of removing the organic solvent after dissolving the resin composition in an organic solvent and impregnating the fiber reinforced substrate (wet method), and heating the resin composition There is a method (dry method) in which the viscosity is lowered and impregnated into the fiber reinforced base material. The dry method is preferable because no organic solvent remains. When manufacturing a prepreg by a dry method, in order to impregnate a resin composition in a fiber reinforced base material, it is necessary to heat until it becomes the viscosity which can impregnate a resin composition.

  In structural material applications such as aircraft and automobiles, further weight reduction and improvement in material strength are strongly demanded with the recent increase in demand. By adding an additive such as a toughness-imparting agent to the resin composition to improve the strength, or by increasing the toughness of the matrix resin itself, the viscosity of the resin composition increases, which is sufficient for the fiber-reinforced substrate. Impregnation is becoming difficult. It takes a long time to heat these resin compositions until they can be impregnated, and the prepreg productivity decreases. Moreover, when using a thermosetting resin as a resin composition, since the hardening reaction of a thermosetting resin advances by heating for a long time, the tack property, drape property, etc. of a prepreg obtained may be deteriorated. Therefore, it is required to lower the viscosity so that the resin composition can be impregnated in a short time.

  Patent Document 1 includes an impregnation roll for bringing a liquid resin into contact with a fiber base material, a resin impregnation tank for supplying the liquid resin to the impregnation roll and the fiber base material, and the resin impregnation tank can be vibrated by an ultrasonic vibration device. A resin impregnating device attached to is disclosed. This apparatus intends to promote the impregnation of the liquid resin into the fiber base material by applying ultrasonic vibration to the fiber base material impregnated with the liquid resin in a wet method.

JP-A-11-226952

  Conventionally, when a prepreg is produced by a dry method using a high-viscosity resin composition, it takes a long time to raise the temperature to a temperature at which the resin composition impregnated into the fiber reinforced substrate can be impregnated. The subject of this invention is providing the manufacturing method of a prepreg which heats up in a short time to the temperature which can be impregnated with a resin composition, when manufacturing a prepreg by a dry process.

  In the case of producing a prepreg by a dry method, the inventors of the present invention can instantaneously raise the temperature to a temperature at which the resin composition can be impregnated by heating the resin composition by a predetermined method. The headline and the present invention were completed.

  The present invention for solving the above problems is as follows.

[1] A layer of a resin composition is laminated on at least one surface of a fiber reinforced substrate, and the resin composition is melted by heating and pressing the resin composition layer to impregnate the fiber reinforced substrate. A method of manufacturing a prepreg
A method for producing a prepreg, wherein a rate of temperature rise during heating of the resin composition is 100 ° C./second or more.

  [2] The prepreg manufacturing method according to [1], wherein the heating temperature of the resin composition is equal to or higher than the gelation temperature of the resin composition.

  [3] The method for producing a prepreg according to [1] or [2], wherein the heating time of the resin composition is less than 1 second.

  [4] The prepreg manufacturing method according to any one of [1] to [3], wherein the heating of the resin composition is ultrasonic heating, induction heating, laser heating, or superheated steam heating.

  [5] The prepreg manufacturing method according to any one of [1] to [3], wherein the heating of the resin composition is ultrasonic heating.

  [6] The prepreg manufacturing method according to any one of [1] to [5], wherein the resin composition is a resin composition containing a thermosetting resin.

  [7] The prepreg manufacturing method according to any one of [1] to [6], wherein the fiber-reinforced base material is a fiber-reinforced base material containing carbon fibers.

  In the method for producing a prepreg of the present invention, the resin composition impregnated in the fiber reinforced base material is instantaneously melted. Therefore, the productivity of prepreg is high. Moreover, when using a thermosetting resin as a resin composition which comprises a prepreg, since the heating time of a resin composition is short, hardening of a thermosetting resin can be suppressed highly. Therefore, the selection range of the resin constituting the prepreg is expanded.

FIG. 1 is an explanatory view showing a configuration example of a resin impregnation apparatus used in the prepreg manufacturing method of the present invention. FIG. 2 is an explanatory view showing another configuration example of the resin impregnation apparatus used in the prepreg manufacturing method of the present invention. FIG. 3 is an explanatory diagram showing a manufacturing process of a prepreg manufactured using the resin impregnation apparatus of FIG. FIG. 4 is an explanatory view showing another configuration example of the resin impregnation apparatus used in the prepreg manufacturing method of the present invention.

In the prepreg manufacturing method of the present invention, a layer of a resin composition is laminated on at least one surface of a fiber reinforced base material, and the resin composition is melted by heating and pressurizing the layer of the resin composition. Impregnate inside. The temperature rising rate during heating of the resin composition is 100 ° C./second or more. Examples of the heating method with a temperature increase rate of 100 ° C./second or more include ultrasonic heating, induction heating, laser heating, and superheated steam heating. From the viewpoint that preheating is not required, thermal efficiency is high, and manufacturing equipment can be simply configured, ultrasonic heating is preferable. In addition, as for the conventional heating method which makes a resin composition contact a heating metal plate, a temperature increase rate is about 30-50 degree-C / sec.
Hereinafter, the manufacturing method of the prepreg by ultrasonic heating is demonstrated.

(1) Resin impregnation apparatus FIG. 1 is an explanatory view showing a configuration example of a resin impregnation apparatus for impregnating a fiber reinforced base material with a resin composition by ultrasonic heating.

  In FIG. 1, 100 is a resin impregnation apparatus. The resin impregnation apparatus 100 is roughly constituted by a heating unit composed of an ultrasonic oscillator 11, an ultrasonic transducer 13 and an ultrasonic horn 15, and an impregnation unit composed of an impregnation roller 21.

The heating unit is configured as follows.
The ultrasonic oscillator 11 is connected to an ultrasonic vibrator 13, and an ultrasonic horn 15 is attached to the ultrasonic vibrator 13. The ultrasonic oscillator 11 converts an electric signal of 50/60 Hz into an electric signal of 15 to 35 kHz and supplies the electric signal to the ultrasonic vibrator 13. The ultrasonic transducer 13 converts the electrical signal supplied from the ultrasonic oscillator 11 into ultrasonic vibration energy of 15 to 35 kHz and supplies it to the ultrasonic horn 15. The ultrasonic horn 15 concentrates the ultrasonic vibration energy generated from the ultrasonic vibrator 13 on the tip of the horn. The ultrasonic horn 15 applies ultrasonic vibration to the substance passing under the tip. A substance to which ultrasonic vibration is applied generates heat due to frictional heat generated by ultrasonic vibration.

  A plurality (six in FIG. 1) of impregnation rollers 21 are provided opposite to the rear stage of the heating unit. The impregnation roller 21 is configured so as to sandwich a sheet-like material passing between the impregnation rollers 21 disposed facing each other in the thickness direction.

(2) Manufacturing method of prepreg Next, operation | movement of the resin impregnation apparatus 100 at the time of prepreg manufacture and the manufacturing method of a prepreg are demonstrated.

  In FIG. 1, 34 is a substrate-resin laminate. The base material-resin laminate 34 is composed of a fiber reinforced base material and a resin composition layer laminated on at least one surface of the fiber reinforced base material. The resin composition layer is in a state where at least a part of the fiber reinforced base material is not impregnated. Details of the substrate-resin laminate 34 will be described later. The base material-resin laminate 34 travels in the direction of arrow A in the figure by the transport roller 25. When the base material-resin laminate 34 passes under the ultrasonic horn 15, ultrasonic vibration is applied to generate heat. Thereby, the resin composition layer which comprises the base-resin laminated body 34 fuse | melts instantly, and a viscosity falls. The base material-resin laminate 34 in which the resin composition is in a molten state is then sent to the impregnation roller 21 where it is nipped. Thereby, the resin composition layer which comprises the base material-resin laminated body 34 is impregnated in a fiber reinforced base material. The substrate-resin laminate 34 discharged from the impregnation roller 21 is cooled (naturally cooled in FIG. 1) to obtain a prepreg 36.

  The temperature rising rate of the resin composition is 100 ° C./second or more, preferably 300 ° C./second or more, and more preferably 500 ° C./second or more. The upper limit is not particularly limited, but is usually less than 2500 ° C./second. When it is less than 100 ° C./second, the effect of improving the prepreg productivity is low.

  The heating temperature of the resin composition is preferably 150 to 500 ° C, and more preferably 200 to 500 ° C.

  The resin impregnation apparatus 100 instantaneously heats the base material-resin laminate 34 by ultrasonic vibration, but in order to maintain the heated state until the impregnation of the resin composition into the fiber reinforced base material is completed, an impregnation roller An auxiliary heating device 23 may be provided in the vicinity of 21. Examples of the auxiliary heating device 23 include a metal hot plate.

  The resin impregnation apparatus 100 is provided with a plurality of pairs of impregnation rollers. However, the present invention is not limited to this, and the impregnation may be performed by one roller. Each roller preferably forms irregularities on the roller surface to reduce the contact area with the substrate-resin laminate 34 and the prepreg 36. The irregularities are preferably formed such that the contact area with the substrate-resin laminate 34 and the prepreg 36 is 1/5 or less, and more preferably 1/8 or less. In order to reduce the frictional resistance of the roller surface, it is also effective to construct the roller with a material such as Teflon (registered trademark of DuPont), ceramic, or coat the roller surface with the material.

  The ultrasonic oscillator 11 used in the present invention is not particularly limited as long as it emits ultrasonic waves. The frequency is preferably 10 to 100 kHz, more preferably 10 to 60 kHz, and particularly preferably 15 to 40 kHz. When the frequency is less than 10 kHz, the temperature of the base material-resin laminate is not sufficiently increased. When the frequency exceeds 100 kHz, the temperature rises too much and the resin is cured.

  The vibration amplitude of the ultrasonic horn 15 is preferably 10 to 80 μm, and more preferably 40 to 80 μm. When the vibration amplitude is less than 10 μm, the temperature does not rise sufficiently. When the vibration amplitude exceeds 80 μm, the temperature rises too much and the resin is cured.

  The output of the ultrasonic oscillator is preferably 100 to 4000 W, and more preferably 400 to 1000 W. When the output is less than 100 W, the temperature does not rise sufficiently. When the output exceeds 4000 W, the temperature rises too much and the resin is cured.

  The application time of ultrasonic waves is preferably 1 second or less. Although a lower limit is not specifically limited, Usually, it is 0.1 second or more, and 0.2 second or more is preferable. The application time of ultrasonic waves can be adjusted by the speed at which the object to be heated passes through the ultrasonic horn 15 portion. Moreover, the maximum temperature reached of the resin composition can be controlled by adjusting the application time of ultrasonic waves.

  Since the above resin impregnation apparatus can instantaneously raise the temperature of the resin composition to a target temperature, the time during which the resin composition is exposed to a high temperature can be greatly shortened as compared with heating using a conventional hot plate. Therefore, the viscosity of the resin composition can be further reduced by heating to a temperature higher than that of the conventional method, and the impregnation property of the resin composition with respect to the fiber reinforced base material can be further increased. For example, when a thermosetting resin in which a thermoplastic resin is dissolved is used as the resin constituting the prepreg, the above resin impregnation apparatus instantly sets the temperature of the high viscosity resin composition in which the thermoplastic resin is dissolved. Therefore, the viscosity of the resin composition can be further lowered by heating to a temperature higher than that of the conventional method, and the impregnation property of the resin composition with respect to the fiber reinforced base material can be further increased. Even if the resin composition is impregnated by such a method, the time for exposure to the vicinity of the curing temperature of the thermosetting resin is very short, so that the curing reaction of the thermosetting resin does not substantially proceed. On the other hand, in the case of conventional heating using a hot plate, it takes a long time to reach the impregnation temperature. Therefore, the resin composition is exposed for a long time near the curing temperature. As a result, the curing reaction of the resin composition is likely to proceed.

  In the resin impregnation apparatus 100, the heating unit and the impregnation unit are disposed in different zones. However, the present invention is not limited thereto, and the heating unit and the impregnation unit may be disposed in the same zone. FIG. 2 is an explanatory view showing another configuration example of the resin impregnation apparatus. The same components as those in FIG. 1 are denoted by the same reference numerals, and the description thereof is omitted. In FIG. 2, 200 is a resin impregnation apparatus, and an impregnation roller 27 is disposed in place of the impregnation roller 21 of FIG. The impregnation roller 27 is provided to face the ultrasonic horn 15. The ultrasonic horn 15 is configured so that the load applied to the tip of the ultrasonic horn 15 can be adjusted by a load applying cylinder 17 provided on the ultrasonic horn 15.

  As the base material-resin laminate 34 passes between the tip of the ultrasonic horn 15 and the impregnation roller 27, the resin composition layer is melted by ultrasonic vibration. Further, the molten resin composition is impregnated in the fiber reinforced base material by the clamping pressure between the tip of the ultrasonic horn 15 and the impregnation roller 27. The resin composition layer constituting the substrate-resin laminate 34 rises to a temperature at which the tip of the ultrasonic horn 15 can be impregnated instantaneously. Therefore, when the resin impregnation apparatus 200 is used, melting and impregnation of the resin composition layer can be achieved substantially simultaneously. That is, the prepreg manufacturing method using this apparatus can impregnate the fiber reinforced base material while melting the resin composition, and the process is completed in 1 second or less.

  When the adhesiveness of the resin is high, the substrate-resin laminate or the prepreg obtained is wound around each roller, or the resin adheres to each roller. In order to prevent this, it is preferable to transport the substrate-resin laminate and the prepreg obtained together with the release paper.

FIG. 3 is an explanatory view showing a process of manufacturing a base material-resin laminate and impregnating a fiber reinforced base material with a resin composition layer constituting the base material-resin laminate using the resin impregnation apparatus 100. It is. The configuration of the resin impregnation apparatus 100 is as described in FIG.
The fiber reinforced base material 30 is conveyed by the conveyance roller 25 in the direction of arrow A in the figure. On both surfaces of the fiber reinforced substrate 30, resin films with release paper supplied from the resin film supply rollers 32a and 32b are respectively laminated. Thereby, the substrate-resin laminate 34 is obtained. The substrate-resin laminate 34 is subjected to ultrasonic vibration at the lower part of the ultrasonic horn 15. Thereby, the resin film which comprises the base material-resin laminated body 34 will be in a molten state. The substrate-resin laminate 34 in which the resin film is in a molten state is impregnated with the molten resin film in the fiber reinforced substrate by being sandwiched between the impregnation rollers 21. The base material-resin laminate 34 discharged from the impregnation roller 21 is allowed to cool and becomes a prepreg 36 with release paper. The release paper on one surface side of the prepreg 36 with release paper is taken up and collected by the release paper take-up roller 38. As a result, a prepreg 40 with release paper attached to the other surface is obtained, and this prepreg 40 is taken up by the prepreg take-up roller 42.

  The resin impregnation apparatus 100 is configured so that the prepreg can be continuously manufactured using the transport roller 25, but is not limited thereto, and may be configured in a batch type. FIG. 4 shows a batch type resin impregnation apparatus 400. In the resin impregnation apparatus 400, the mounting plate 29 is disposed so as to face the ultrasonic horn 15. The base material-resin laminate 34 placed on the placement plate 29 is pinched between the ultrasonic horn 15 and the placement plate 29 by the operation of the load loading cylinder 17. In this state, ultrasonic vibration is applied from the ultrasonic horn 15 and the resin composition is melted and impregnated simultaneously.

(3) Fiber reinforced base material A fiber reinforced base material is a base material obtained by processing reinforcing fibers into various shapes. The fiber reinforced base material is preferably in the form of a sheet. As the reinforcing fiber, for example, carbon fiber, glass fiber, aramid fiber, silicon carbide fiber, polyester fiber, ceramic fiber, alumina fiber, boron fiber, metal fiber, mineral fiber, rock fiber and slug fiber can be used. Among these reinforcing fibers, carbon fibers, glass fibers, and aramid fibers are preferable. Carbon fiber is particularly preferable, and PAN-based carbon fiber having high tensile strength is most preferable because a composite material having high specific strength and high specific modulus, light weight and high strength can be obtained.

The carbon fiber preferably has a tensile modulus of 170 to 600 GPa, particularly preferably 220 to 450 GPa. The tensile strength of the carbon fiber is preferably 3920 MPa (400 kgf / mm ² ) or more. By using such a carbon fiber, the mechanical properties of the composite material can be particularly improved.

  As a sheet-like fiber reinforced substrate, a sheet made of a large number of reinforcing fibers aligned in one direction, bi-directional woven fabrics such as plain weave and twill weave, multiaxial woven fabrics, non-woven fabrics, mats, knits, braids, and reinforcing fibers Paper. The thickness of the sheet material is preferably 0.01 to 3 mm, more preferably 0.1 to 1.5 mm.

(4) Resin composition Examples of the resin composition used in the present invention include a thermosetting resin, a thermoplastic resin, and a mixture thereof. The production method of the present invention can be particularly preferably used when the resin composition impregnated in the prepreg contains a thermosetting resin.

  Although the thermosetting resin used for this invention is not specifically limited, An epoxy resin, a polyimide resin, and these modified resin are illustrated. As the curing agent, a known curing agent that cures these resins can be used. When an epoxy resin is used as the thermosetting resin, dicyandiamide, various isomers of an aromatic amine curing agent, and aminobenzoic acid esters are exemplified. Aromatic diamine compounds such as 4,4'-diaminodiphenylsulfone, 3,3'-diaminodiphenylsulfone, and 4,4'-diaminodiphenylmethane are particularly preferable because a cured product having high heat resistance can be obtained.

  The thermoplastic resin used in the present invention is not particularly limited, but polyamide, polyacetal, polyphenylene oxide, polyphenylene sulfide, polyester, polyamideimide, polyimide, polyether ketone, polyether ether ketone, polyethylene naphthalate, polyaramid, polyether nitrile, poly Benzimidazole is exemplified. Among these, polyamide, polyamideimide, and polyimide are preferable because of high toughness and heat resistance.

  These resin compositions are preferably formed into a sheet shape by a known method. The sheet-like resin composition can be produced by a known method. For example, it can be produced by casting and casting on a support such as release paper or release sheet using a die coater, applicator, reverse roll coater, comma coater, knife coater, or the like. The resin temperature during sheeting is appropriately set according to the composition and viscosity of the resin.

[Water absorption rate]
The prepreg was cut to 100 × 100 mm, and the mass (W1) was measured. Thereafter, the prepreg was submerged in a desiccator. The inside of the desiccator was decompressed to 10 kPa or less to replace the air and water inside the prepreg. The prepreg was taken out of the water, the surface water was wiped off, and the mass (W2) of the prepreg was measured. From these measured values, the following formula: water absorption (%) = [(W2-W1) / W1] × 100
W1: Mass of prepreg (g)
W2: Mass of prepreg after water absorption (g)
Was used to calculate the water absorption rate.

[Drapability]
The prepreg was stored at a temperature of 26.7 ° C. and a humidity of 65% for 2 days, and then cut into 30 mm in the fiber direction and 10 mm in the direction perpendicular to the fiber direction. The cut prepreg was laminated on a metal plate bent at an angle of 90 degrees with a curvature of 12.7 mm, and the drapability was evaluated in the laminated state after 10 seconds. The evaluation results were expressed by the following criteria (◯, ×).
○: Follows a metal plate.
X: It does not follow a metal plate.

  Hereinafter, the present invention will be described in more detail with reference to examples.

Example 1
A fiber reinforced base material having a fiber basis weight of 190 g / m ² was prepared using 80 carbon fiber IMS60 24K (24,000 fermentaments, tensile strength 5,700 MPa, tensile elastic modulus 285 GPa) manufactured by Toho Tenax Co., Ltd. as the reinforcing fiber bundle. did. A base-resin laminate was prepared by laminating a thermosetting resin film having a resin basis weight of 40 g / m ^{2 on} both surfaces of the fiber reinforced base material. The fiber content of this substrate-resin laminate is 70% by mass.
This substrate-resin laminate was heated using the resin impregnation apparatus shown in FIG. This apparatus used W3080 (frequency 20 kHz, output 2400 kW) manufactured by Nippon Huchaa Co., Ltd., and the amplitude was 60 μm. Moreover, the dimension of the base-resin laminated body was 25 mm x 50 mm, and the pressure concerning a base-resin laminated body was 1.7 MPa. By applying ultrasonic vibration for 0.2 seconds, the substrate-resin laminate was raised to 313 ° C. When the application of ultrasonic waves was stopped, the temperature of the substrate-resin laminate decreased to room temperature in 1 second. The resin film of the substrate-resin laminate was sufficiently impregnated in the fiber reinforced substrate. The obtained prepreg had moderate flexibility.

(Example 2-5)
A prepreg was prepared in the same manner as in Example 1 except that each condition was changed as described in Table 1.

(Comparative Example 1)
A fiber reinforced base material having a fiber basis weight of 190 g / m ² was prepared using 80 carbon fiber IMS60 24K (24,000 fermentaments, tensile strength 5,700 MPa, tensile elastic modulus 285 GPa) manufactured by Toho Tenax Co., Ltd. as the reinforcing fiber bundle. did. A base-resin laminate was prepared by laminating a thermosetting resin film having a resin basis weight of 40 g / m ^{2 on} both surfaces of the fiber reinforced base material. The fiber content of this substrate-resin laminate is 70% by mass.
This substrate-resin laminate was heated and pressurized using a heating press. The pressure applied to the base material-resin laminate was 1.7 MPa. The time until the temperature of the base material-resin laminate reached 135 ° C. was 4.0 seconds. The resin composition was partially impregnated in the fiber reinforced base material, and was not sufficiently impregnated.

(Comparative Example 2)
A prepreg was produced in the same manner as in Comparative Example 1. The pressure applied to the base material-resin laminate was 1.7 MPa. The time until the temperature of the substrate-resin laminate reached 190 ° C. was 4.0 seconds. The resin composition was sufficiently impregnated in the fiber reinforced base material, but there was no flexibility in the prepreg.

DESCRIPTION OF SYMBOLS 100, 200, 400 ... Resin impregnation apparatus 11 ... Ultrasonic oscillator 13 ... Ultrasonic vibrator 15 ... Ultrasonic horn 17 ... Air cylinder for load addition 21, 27 ... Impregnation Roller 23 ... Hot plate 25 ... Conveying roller 29 ... Mounting plate 30 ... Fiber reinforced base material 32a, 32b ... Resin film supply roller 34 ... Base material-resin laminate 36. .... Pre-preg with release paper 38 ... Release paper take-up roller 40 ... Pre-preg 42 ... Pre-preg take-up roller

Claims (7)

A layer of a resin composition is laminated on at least one surface of a fiber reinforced substrate, and the resin composition layer is heated and pressurized to melt the resin composition and impregnate the fiber reinforced substrate into the fiber reinforced substrate. A manufacturing method comprising:
A method for producing a prepreg, wherein a rate of temperature rise during heating of the resin composition is 100 ° C./second or more.   The method for producing a prepreg according to claim 1, wherein the heating temperature of the resin composition is equal to or higher than the gelation temperature of the resin composition.   The method for producing a prepreg according to claim 1 or 2, wherein the heating time of the resin composition is less than 1 second.   The method for producing a prepreg according to any one of claims 1 to 3, wherein the heating of the resin composition is ultrasonic heating, induction heating, laser heating, or superheated steam heating.   The method for producing a prepreg according to any one of claims 1 to 3, wherein the heating of the resin composition is ultrasonic heating.   The prepreg manufacturing method according to claim 1, wherein the resin composition is a resin composition containing a thermosetting resin. The prepreg manufacturing method according to claim 1, wherein the fiber reinforced base material is a fiber reinforced base material containing carbon fibers.

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