Patent Description:
Application of a carbon fiber reinforced plastic composite material (CFRP) to a structural material for a fan rotor blade, a fan case, and the like of a jet engine has been under consideration in recent years. The carbon fiber reinforced plastic composite material is a lightweight and high strength composite material which is formed from carbon fibers that serve as a reinforcing material and from a matrix resin layer. However, the carbon fiber reinforced plastic composite material is liable to cause delamination at an interface between the carbon fibers and the matrix resin layer, thus possibly leading to deterioration in mechanical properties and the like. Due to the aforementioned reason, adhesion strength between the carbon fibers and the matrix resin layer is improved by entwining carbon nanotubes with surfaces of the carbon fibers (<CIT>). Furthermore, PTL <NUM> discloses a method for producing large quantities of continuous macroscopic carbon fiber from single-wall carbon nanotubes using carbon feedstocks at moderate temperatures, wherein a mixture comprising single-wall carbon nanotubes and amorphous carbon contaminate is heated under oxidizing conditions to remove the amorphous carbon and a product comprising at least about <NUM>% a by weight of single-wall carbon nanotubes is recovered. Eventually, NPTL <NUM> discloses a tube-style radio frequency plasma enhanced chemical vapor deposition system, wherein graphene nanowalls are directly deposited on carbon fiber for improving the interface strength in composites.

[NPTL <NUM>] Directly deposited graphene nanowalls on carbon fiber for improving the interface strength in composites by Chi Yao et al.

In the meantime, the carbon fiber reinforced plastic composite material is usually molded by using a material such as a prepreg that is prepared by impregnating long continuous carbon fibers with a resin and semicuring the resin. When the surfaces of the above-mentioned continuous carbon fibers are entwined with the carbon nanotubes, the carbon nanotubes may fail to sufficiently produce an anchoring effect on the matrix resin layer due to their behavior to flocculate together. Accordingly, there is risk of deterioration in adhesion at the interface between the continuous carbon fibers and the matrix resin layer when the carbon fiber reinforced plastic composite material is formed.

Given the situation, an object of this disclosure is to provide a carbon fiber complex material according to claim <NUM> and a manufacturing method thereof according to claim <NUM> which are capable of improving adhesion between a continuous carbon fiber and a matrix resin layer when a carbon fiber reinforced plastic composite material is formed, and to provide a manufacturing apparatus for a carbon fiber complex material according to claims <NUM> and <NUM>, a prepreg according to claim <NUM>, and a carbon fiber reinforced plastic composite material according to claim <NUM>. Preferable embodiments are claimed by the dependent claims.

A carbon fiber complex material according to this disclosure is a carbon fiber complex material for a carbon fiber reinforced plastic composite material, including a carbon fiber material formed from a continuous carbon fiber and carbon nanowalls formed on a surface of the continuous carbon fiber.

In the carbon fiber complex material according to this disclosure, the carbon fiber material may be a carbon fiber fabric woven from the continuous carbon fibers.

In the carbon fiber complex material according to this disclosure, the carbon nanowalls may be formed upright on the surface of the continuous carbon fiber.

In the carbon fiber complex material according to this disclosure, the carbon nanowalls may be formed to extend outward in a radial direction of the continuous carbon fiber.

In the carbon fiber complex material according to this disclosure, the carbon nanowalls may be formed away from one another.

In the carbon fiber complex material according to this disclosure, a height of each carbon nanowall may be equal to or below <NUM>.

In the carbon fiber complex material according to this disclosure, a length of the continuous carbon fiber may be equal to or above <NUM>.

A method of manufacturing a carbon fiber complex material according to this disclosure is a method of manufacturing a carbon fiber complex material for a carbon fiber reinforced plastic composite material, including a feeding step of feeding a carbon fiber material formed from a continuous carbon fiber out of a feeding bobbin around which the carbon fiber material is wound, a carbon nanowall forming step of forming carbon nanowalls on a surface of the continuous carbon fiber of the carbon fiber material by heating the carbon fiber material fed out of the feeding bobbin to <NUM> or above and supplying a raw material gas containing a carbon source gas to cause a reaction in plasma, and a winding step of winding the carbon fiber material, which is provided with the carbon nanowalls on the surface of the continuous carbon fiber, around a winding bobbin.

The method of manufacturing a carbon fiber complex material according to this disclosure may further include a surface activation treatment step of supplying plasma containing an inert gas but no carbon source gas to the continuous carbon fiber of the carbon fiber material fed out of the feeding bobbin before formation of the carbon nanowalls on the surface of the continuous carbon fiber.

In the method of manufacturing a carbon fiber complex material according to this disclosure, the carbon nanowall forming step may include mixing the raw material gas with hydrogen gas.

A manufacturing apparatus for a carbon fiber complex material according to this disclosure is a manufacturing apparatus for a carbon fiber complex material for a carbon fiber reinforced plastic composite material, including an apparatus body provided with a chamber, a raw material gas supply unit provided to the apparatus body and configured to supply a raw material gas containing a carbon source gas to the chamber, a plasma generation unit provided to the apparatus body and configured to generate plasma in the chamber, a feeding bobbin around which a carbon fiber material formed from a continuous carbon fiber is wound, the feeding bobbin configured to feed the carbon fiber material out, a winding bobbin configured to wind the carbon fiber material provided with carbon nanowalls on a surface of the continuous carbon fiber, and a heating unit located opposite to the plasma generated in the chamber while interposing the carbon fiber material in between, and configured to heat the carbon fiber material.

In the manufacturing apparatus for a carbon fiber complex material according to this disclosure, the heating unit may include a preheating unit provided to extend toward the feeding bobbin and be configured to preheat the continuous carbon fiber of the carbon fiber material before formation of the carbon nanowalls.

A manufacturing apparatus for a carbon fiber complex material according to this disclosure is a manufacturing apparatus for a carbon fiber complex material for a carbon fiber reinforced plastic composite material, including an apparatus body provided with a chamber which has a first sub-chamber in which a carbon fiber material formed from a continuous carbon fiber is subjected to a surface activation treatment, a second sub-chamber in which carbon nanowalls are formed on a surface of the continuous carbon fiber of the carbon fiber material subjected to the surface activation treatment, and a partition wall partitioning the first sub-chamber and the second sub-chamber, the partition wall including a slit to allow insertion of the carbon fiber material subjected to the surface activation treatment, a surface activation treatment gas supply unit provided to the apparatus body and configured to supply a surface activation treatment gas containing an inert gas but no carbon source gas to the first sub-chamber, a raw material gas supply unit provided to the apparatus body and configured to supply a raw material gas containing the carbon source gas to the second sub-chamber, a first plasma generation unit provided to the apparatus body and configured to generate plasma in the first sub-chamber, a second plasma generation unit provided to the apparatus body and configured to generate plasma in the second sub-chamber, a feeding bobbin around which the carbon fiber material is wound, the feeding bobbin provided to the first sub-chamber and configured to feed the carbon fiber material out, a winding bobbin provided to the second sub-chamber and configured to wind the carbon fiber material provided with the carbon nanowalls on the surface of the continuous carbon fiber, a first heating unit provided to the first sub-chamber, located opposite to the first plasma generation unit while interposing the carbon fiber material in between, and configured to heat the carbon fiber material, and a second heating unit provided to the second sub-chamber, located opposite to the second plasma generation unit while interposing the carbon fiber material subjected to the surface activation treatment in between, and configured to heat the carbon fiber material subjected to the surface activation treatment.

A prepreg according to this disclosure is a prepreg including the above-described carbon fiber complex material and a semicured resin layer made of a semicured resin and provided to the carbon fiber complex material.

A carbon fiber reinforced plastic composite material according to this disclosure is a carbon fiber reinforced plastic composite material including the above-described carbon fiber complex material and a matrix resin layer made of a cured resin material and provided to the carbon fiber complex material.

According to the configuration mentioned above, the carbon nanowalls are formed on the surface of the continuous carbon fiber of the carbon fiber material. Thus, it is possible to improve adhesion between the continuous carbon fiber and a matrix resin layer when the carbon fiber reinforced plastic composite material is formed.

A first embodiment of this disclosure will be described below in detail with reference to the drawings. <FIG> is a diagram showing a configuration of a carbon fiber complex material <NUM>. The carbon fiber complex material <NUM> is used in a carbon fiber reinforced plastic composite material. The carbon fiber complex material <NUM> may be used as a reinforcing material in the carbon fiber reinforced plastic composite material. The carbon fiber complex material <NUM> includes a carbon fiber material <NUM> formed from a continuous carbon fiber <NUM>, and carbon nanowalls <NUM> formed on a surface of the continuous carbon fiber <NUM>.

A carbon fiber material <NUM> is formed from a continuous carbon fiber <NUM>. The continuous carbon fiber <NUM> may be made of a carbon fiber monofilament. The continuous carbon fiber <NUM> may be made of a carbon fiber bundle which is formed by bundling numerous carbon fiber monofilaments. For example, a <NUM> carbon fiber bundle formed by bundling <NUM> carbon fiber monofilaments, a <NUM> carbon fiber bundle formed by bundling <NUM> carbon fiber monofilaments, and the like can be used as the above-mentioned carbon fiber bundle. A length of the continuous carbon fiber <NUM> may be set equal to or above <NUM>, for example. A PAN-based carbon fiber, a pitch-based carbon fiber, and the like can be used as the continuous carbon fiber <NUM>. The carbon fiber material <NUM> may be formed from a carbon fiber fabric which is woven from the continuous carbon fibers <NUM>. For example, a plain woven carbon fiber fabric, a sateen woven carbon fiber fabric, a twill woven carbon fiber fabric, and the like can be used as the above-mentioned carbon fiber fabric.

The carbon nanowalls <NUM> are formed on a surface of the continuous carbon fiber <NUM>. <FIG> is an enlarged schematic diagram of the surface of the continuous carbon fiber <NUM>. Each carbon nanowall <NUM> is a nanostructure in which nanosized crystallites having a graphite structure are formed in an aligned manner in a plane. The carbon nanowalls <NUM> have a self-organizing property and numerous carbon nanowalls <NUM> are therefore formed on the surface of the continuous carbon fiber <NUM> at intervals with one another. The carbon nanowalls <NUM> may be formed upright on the surface of the continuous carbon fiber <NUM>, or formed almost vertically upright on the surface of the continuous carbon fiber <NUM>. Meanwhile, the carbon nanowalls <NUM> may be formed in such a way as to project from the surface of the continuous carbon fiber <NUM> outward in a radial direction of the continuous carbon fiber <NUM>. Moreover, the carbon nanowalls <NUM> may be formed away from one another. In this way, when the carbon fiber reinforced plastic composite material is formed, an uneven structure formed of the carbon nanowalls <NUM> enters into the matrix resin layer and exerts an anchoring effect. Thus, adhesion between the continuous carbon fiber <NUM> and the matrix resin layer can be improved. In the meantime, the carbon nanowalls <NUM> are formed at intervals with one another due to the self-organizing property whereby the carbon nanowalls <NUM> are located away from one another without being entwined. This makes it possible to form a finer uneven structure on the surface of the continuous carbon fiber <NUM> so that the anchoring effect can be exerted more prominently.

A height of each carbon nanowall <NUM> may be set equal to or below <NUM>. When the carbon fiber reinforced plastic composite material is formed, as the height of the carbon nanowall <NUM> becomes larger, a distance between every two continuous carbon fibers <NUM> grows larger and the resin layer becomes thicker. This may lead to a failure to occur sufficient bonding strength between the continuous carbon fibers <NUM> and result in deterioration in strength of the carbon fiber reinforced plastic composite material. The carbon nanowalls <NUM> may be formed into a coating on the surface of the continuous carbon fiber <NUM>. The form of the coating means a state in which the carbon nanowalls <NUM> are formed continuously and densely in an axial direction and a circumferential direction of the fiber on the surface of the continuous carbon fiber <NUM> whereby the surface of the continuous carbon fiber <NUM> is covered with the carbon nanowalls <NUM>. The surface of the continuous carbon fiber <NUM> covered with the coating formed from the carbon nanowalls <NUM> makes it possible to further improve the adhesion between the continuous carbon fiber <NUM> and the matrix resin layer when the carbon fiber reinforced plastic composite material is formed.

The carbon fiber complex material <NUM> discussed in this embodiment relates to a single continuous carbon fiber <NUM> provided with the carbon nanowalls <NUM>. The continuous carbon fiber <NUM> has a certain length. Accordingly, as for a method of housing the carbon fiber complex material <NUM>, the single continuous carbon fiber <NUM> provided with the carbon nanowalls <NUM> can be housed by winding the continuous carbon fiber <NUM> around a bobbin or the like. Meanwhile, as for the method of housing the carbon fiber complex material <NUM>, multiple continuous carbon fibers <NUM> provided with the carbon nanowalls <NUM> may be housed by winding the continuous carbon fibers <NUM> around and then bundling the continuous carbon fibers <NUM> together with a band or the like. In the meantime, as for the method of housing the carbon fiber complex material <NUM>, multiple continuous carbon fibers <NUM> provided with the carbon nanowalls <NUM> may be housed by bundling the continuous carbon fibers <NUM> together with a band or the like without winding the continuous carbon fibers <NUM> around. In addition, it is possible to use publicly known methods of housing a continuous fiber such as housing a continuous fiber while attaching two end portions thereof to a strip of paper.

Next, a description will be given of a method of manufacturing the carbon fiber complex material <NUM>. First, a manufacturing apparatus <NUM> for the carbon fiber complex material <NUM> will be described. <FIG> is a diagram showing a configuration of the manufacturing apparatus <NUM> for the carbon fiber complex material <NUM>. <FIG> sets up the XYZ Cartesian coordinate system and positional relations among respective constituents will be described with reference to the XYZ Cartesian coordinate system. Moreover, the point of origin is determined at a plasma source <NUM> to be described later, for example, and a predetermined direction in a horizontal plane is defined as x-axis method, a direction orthogonal to the x-axis direction within the horizontal plane is defined as a y-axis direction, and a direction (a vertical direction) orthogonal to the x-axis direction and to the y-axis direction is defined as z-axis direction.

The manufacturing apparatus <NUM> for the carbon fiber complex material <NUM> includes an apparatus body <NUM> provided with a chamber <NUM>, and a plasma generator <NUM> to be described later which is provided to the apparatus body <NUM> and configured to generate plasma. The chamber <NUM> includes an exhaust pipe <NUM> to discharge a gas in the chamber <NUM>. The exhaust pipe <NUM> connects with the inside of the chamber <NUM>. Meanwhile, the exhaust pipe <NUM> is connected to a vacuum pump <NUM>. The inside of the chamber <NUM> is evacuated by the vacuum pump <NUM>. The exhaust pipe <NUM> is provided with a valve mechanism (not shown) such as an electromagnetic valve for exhausting or stopping the gas in the chamber <NUM>.

A raw material gas supply unit <NUM> is provided to the apparatus body <NUM> and has a function to supply a raw material gas for forming the carbon nanowalls <NUM> in the chamber <NUM>. The raw material gas supply unit <NUM> is provided outside the chamber <NUM> and includes storage gas tanks <NUM>, <NUM> storing the raw material gas, and a supply pipe <NUM> connected to the storage gas tanks <NUM>, <NUM> and to the chamber <NUM> for supplying the raw materials gas from the storage gas tanks <NUM>, <NUM> to the chamber <NUM>. The supply pipe <NUM> is provided on a vertically upper side of the chamber <NUM> and extends from the outside to the inside of the chamber <NUM>. Moreover, the supply pipe <NUM> projects from an inner peripheral surface of the chamber <NUM> to the inside thereof. The supply pipe <NUM> is provided with a valve mechanism (not shown) such as an electromagnetic valve for supplying or stopping the raw material gas. A carbon source gas such as a hydrocarbon gas including methane (CH<NUM>), ethane (C<NUM>H<NUM>), ethylene (C<NUM>H<NUM>), acetylene (C<NUM>H<NUM>), and mixtures thereof is stored in the storage gas tank <NUM>. Hydrogen gas is stored in the storage gas tank <NUM>. When hydrogen gas is supplied in addition to the carbon source gas, these gases may be supplied as a mixed gas or supplied separately from each other.

The plasma generator <NUM> is provided to the apparatus body <NUM> and includes a tubular electric discharge chamber <NUM> that connects with the inside of the chamber <NUM> and extends in the x-axis direction, an electric discharge gas supply unit <NUM> that supplies an electric discharge gas used for generating plasma in the electric discharge chamber <NUM>, and a plasma source <NUM> that generates the plasma in the electric discharge chamber <NUM>. The plasma source <NUM> is inserted into the electric discharge chamber <NUM> from one side in the x-axis direction, and connects with the chamber <NUM>. The electric discharge chamber <NUM> extends from an end surface on the one side in the x-axis direction of the chamber <NUM> to the one side in the x-axis direction. To be more precise, the electric discharge chamber <NUM> extends to the one side in the x-axis direction from a connection port <NUM> provided on the end surface on the one side in the x-axis direction of the chamber <NUM>.

The electric discharge gas supply unit <NUM> has a function to supply the electric discharge gas used for generating the plasma in the electric discharge chamber <NUM>. The electric discharge gas supply unit <NUM> includes a storage gas tank <NUM> storing the electric discharge gas, and a supply pipe <NUM> connected to the storage gas tank <NUM> and to the electric discharge chamber <NUM> for supplying the electric discharge gas from the storage gas tank <NUM> to the electric discharge chamber <NUM>. The supply pipe <NUM> is provided with a valve mechanism (not shown) such as an electromagnetic valve for supplying or stopping the electric discharge gas. An inert gas such as argon gas can be used for the electric discharge gas.

The plasma source <NUM> is provided to the electric discharge chamber <NUM> and has a function to generate the plasma in the electric discharge chamber <NUM>. One of plasma guns disclosed in <CIT>, <CIT>, and the like can be used as the plasma source <NUM>, for example. The plasma source <NUM> can cause the electric discharge gas to change into the plasma by means of arc discharge. The plasma source <NUM> may cause the electric discharge gas to change into the plasma by means of direct-current discharge using thermionic emission from a tungsten filament, for example.

A plasma introduction unit <NUM> includes a pair of coils <NUM> provided to the electric discharge chamber <NUM>, and a counter electrode <NUM> provided to the chamber <NUM> and placed opposite to the pair of coils <NUM>. The coils <NUM> are located at a position between the plasma source <NUM> and the connection port <NUM>. The plasma generated in the electric discharge chamber <NUM> is introduced to the chamber <NUM> by applying a voltage between the coils <NUM> and the counter electrode <NUM>. To be more precise, an electron flow of the plasma generated in the electric discharge chamber <NUM> is accelerated by the pair of coils <NUM> and introduced (radiated) to the chamber <NUM> through the connection port <NUM>.

A magnetic field generation unit <NUM> includes large-diameter air-core coils <NUM> provided on two sides in the x-axis direction of the chamber <NUM>, which have a function to shape the plasma introduced to the chamber <NUM> into a sheet form. The coils <NUM> can shape the plasma into the sheet form by generating a magnetic field. To be more precise, the plasma has a substantially circular shape in a YZ plane when the plasma is passed through the connection port <NUM>. After the passage through the connection port <NUM>, the plasma is shaped by the magnetic field generation unit <NUM> into the sheet form that is long in the y-axis direction in the YZ plane. Note that this plasma in the sheet form may also be referred to a sheet plasma P in the following description. As described above, the plasma generator <NUM>, the plasma introduction unit <NUM>, and the magnetic field generation unit <NUM> have a function as a plasma generation unit that generates the plasma in the chamber <NUM>.

A transport unit <NUM> to transport the carbon fiber material <NUM> formed from the continuous carbon fiber <NUM> is provided in the chamber <NUM>. The transport unit <NUM> includes a feeding bobbin <NUM>, a winding bobbin <NUM>, a feeding pulley <NUM>, and a winding pulley <NUM>. Moreover, the transport unit <NUM> includes a driving mechanism <NUM> such as a motor for transmitting a rotary driving force to the winding bobbin <NUM>.

The feeding bobbin <NUM> is a bobbin provided inside the chamber <NUM> of the apparatus body <NUM>. The feeding bobbin <NUM> is located vertically below the connection port <NUM>. The carbon fiber material <NUM> formed from the continuous carbon fiber <NUM> is wound around the feeding bobbin <NUM> and the feeding bobbin <NUM> is formed to be capable of feeding the carbon fiber material <NUM> out. The winding bobbin <NUM> is a bobbin provided inside the chamber <NUM>. The winding bobbin <NUM> is located on another end side in the x-axis direction relative to the feeding bobbin <NUM>. The winding bobbin <NUM> is formed to be capable of winding the carbon fiber material <NUM> provided with the carbon nanowalls <NUM> on the surface of the continuous carbon fiber <NUM>. The rotary driving force is transmitted from the driving mechanism <NUM> such as the motor to the winding bobbin <NUM>. In other words, the carbon fiber material <NUM> is transported in a state of receiving a tensile force. Here, the transport unit <NUM> may include a driving mechanism such as a motor for transmitting a rotary driving force to the feeding bobbin <NUM>. For example, the tensile force to be applied to the carbon fiber material <NUM> is adjustable by controlling a feeding speed of the feeding bobbin <NUM> and a winding speed of the winding bobbin <NUM>.

The feeding pulley <NUM> and the winding pulley <NUM> are pulleys provided inside the chamber <NUM> of the apparatus body <NUM>. The winding pulley <NUM> is located on the other end side in the x-axis direction relative to the feeding pulley <NUM>. The carbon fiber material <NUM> fed out of the feeding bobbin <NUM> is turned to the x-axis direction by the feeding pulley <NUM>. The carbon fiber material <NUM> turned to the x-axis direction is exposed to the sheet plasma P. The carbon fiber material <NUM> exposed to the sheet plasma P is turned by the winding pulley <NUM> and wound around the winding bobbin <NUM>. The carbon nanowalls <NUM> are formed on the surface of the carbon fiber material <NUM> as a consequence of the exposure to the sheet plasma P.

A heating unit <NUM> is provided to the chamber <NUM>. The heating unit <NUM> includes a heating unit body 78a located at a position between the feeding pulley <NUM> and the winding pulley <NUM> in the x-axis direction. The heating unit body 78a heats the carbon fiber material <NUM> turned by the feeding pulley <NUM> from vertically below. Specifically, the heating unit body 78a is opposed to the sheet plasma P generated in the chamber while interposing the carbon fiber material <NUM> in between. The heating unit body 78a may be located vertically below the supply pipe <NUM> so as to facilitate the formation of the carbon nanowalls <NUM>. The carbon nanowalls <NUM> are efficiently formed when the carbon fiber material <NUM> is set equal to or above <NUM>, or set in a range from <NUM> to <NUM>. In other words, at an end portion on a downstream side in a transport direction of the heating unit body 78a, the carbon fiber material <NUM> of this embodiment is set to a temperature equal to or above <NUM>, or in the range from <NUM> to <NUM>. The heating unit body 78a of this embodiment is a heater.

The heating unit <NUM> may include a preheating unit 78b provided to extend toward the feeding bobbin <NUM> (to the one side in the x-axis direction) of the heating unit body 78a and configured to preheat the continuous carbon fiber <NUM> of the carbon fiber material <NUM> before formation of the carbon nanowalls <NUM>. Regarding the preheating unit 78b, it is also possible to dispose the unit on an upstream side of the feeding pulley <NUM>. Meanwhile, the preheating unit 78bmaybe integrated with the heating unit body 78a or provided separately therefrom. By preheating the continuous carbon fiber <NUM> of the carbon fiber material <NUM> with the preheating unit 78b before formation of the carbon nanowalls <NUM>, it is possible to further even out the temperature of the continuous carbon fiber <NUM> at the time of formation of the carbon nanowalls <NUM>. In the meantime, even when a sizing agent or the like adheres to the continuous carbon fiber <NUM>, it is possible to remove the sizing agent or the like by the preheating. The preheating unit 78b can be formed from a heater or the like as with the heating unit body 78a. Meanwhile, a setting temperature of the preheating unit 78b may be set to a higher temperature than the setting temperature of the heating unit body 78a so as to increase the temperature of the carbon fiber material <NUM> quickly.

A control unit (not shown) has a function to control the raw material gas supply unit <NUM>, the plasma generator <NUM>, the plasma introduction unit <NUM>, the magnetic field generation unit <NUM>, the driving mechanism <NUM> for the winding bobbin <NUM>, the heating unit <NUM>, and the like. The control unit (not shown) can conduct or stop the introduction of the raw material gas to the chamber <NUM> by controlling the raw material gas supply unit <NUM>. The control unit (not shown) can conduct or stop the generation of the sheet plasma P in the chamber <NUM> by controlling the plasma generator <NUM>, the plasma introduction unit <NUM>, and the magnetic field generation unit <NUM>. The control unit (not shown) can adjust the start and stop of winding the carbon fiber material <NUM> around, the winding speed of the carbon fiber material <NUM>, and the like by controlling the driving mechanism <NUM> for the winding bobbin <NUM>. The control unit (not shown) can be constructed by using a general computer system and the like.

Next, a description will be given of a method of manufacturing the carbon fiber complex material <NUM>. <FIG> is a flowchart showing a configuration of the method of manufacturing the carbon fiber complex material <NUM>. The method of manufacturing the carbon fiber complex material <NUM> includes a feeding step (S10) of feeding the carbon fiber material <NUM> out, a carbon nanowall forming step (S12) of forming the carbon nanowalls <NUM>, and a winding step (S14) of winding the carbon fiber material <NUM> provided with the carbon nanowalls <NUM> on the surface of the continuous carbon fiber <NUM>. Meanwhile, <FIG> is a diagram for explaining the method of manufacturing the carbon fiber complex material <NUM> in the case where the carbon fiber material <NUM> is formed from the continuous carbon fiber <NUM> made of the carbon fiber monofilament or the carbon fiber bundle. <FIG> is a diagram for explaining the method of manufacturing the carbon fiber complex material <NUM> in the case where the carbon fiber material <NUM> is formed from a carbon fiber fabric woven from the continuous carbon fibers <NUM>.

The feeding step (S10) is a step of feeding the carbon fiber material <NUM> formed from the continuous carbon fiber <NUM> out of the feeding bobbin <NUM> around which the carbon fiber material <NUM> is wound. The fed carbon fiber material <NUM> is guided and turned by the feeding pulley <NUM>. The turned carbon fiber material <NUM> is exposed to the sheet plasma P. In the meantime, the carbon fiber material <NUM> guided by the feeding pulley <NUM> may be preheated by the preheating unit 78b of the heating unit <NUM> before forming the carbon nanowalls <NUM> on the surface of the continuous carbon fiber <NUM>. The preheating of the continuous carbon fiber <NUM> of the carbon fiber material <NUM> with the preheating unit 78b further evens out the temperature of the continuous carbon fiber <NUM> at the time of formation of the carbon nanowalls <NUM> so that the carbon nanowalls <NUM> can be formed stably. In the meantime, even when a sizing agent or the like adheres to the continuous carbon fiber <NUM>, it is possible to remove the sizing agent or the like by the preheating. Of course, the carbon nanowalls <NUM> may be formed in the carbon nanowall forming step (S12) described below while transporting the continuous carbon fiber <NUM> of the carbon fiber material <NUM> without preheating by using the preheating unit 78b.

The carbon nanowall forming step (S12) is a step of forming the carbon nanowalls <NUM> on the surface of the continuous carbon fiber <NUM> of the carbon fiber material <NUM> by heating the carbon fiber material <NUM> fed out of the feeding bobbin <NUM> to <NUM> or above and supplying the raw material gas containing the carbon source gas to cause a reaction in the plasma.

The carbon fiber material <NUM> fed out of the feeding bobbin <NUM> may be heated to <NUM> or above, or in the range from <NUM> to <NUM> inclusive with the heating unit body (the heater) 78a. The carbon nanowalls <NUM> tend to be formed less on the surface of the continuous carbon fiber <NUM> in the case where the temperature of the carbon fiber material <NUM> is below <NUM>.

The raw material gas containing the carbon source gas is supplied into the chamber <NUM> by controlling the raw material gas supply unit <NUM>. As the carbon source gas, it is possible to use a gas such as a hydrocarbon gas including methane (CH<NUM>), ethane (C<NUM>H<NUM>), ethylene (C<NUM>H<NUM>), acetylene (C<NUM>H<NUM>), and mixtures thereof. A mixed gas of the carbon source gas and hydrogen gas may be used as the raw material gas. By adjusting a flow ratio between the carbon source gas and the hydrogen gas, it is possible to control a formation rate and a surface density of the carbon nanowalls <NUM>. In order to increase the formation rate of the carbon nanowalls <NUM>, the flow ratio between the carbon source gas and the hydrogen gas may be set as carbon source gas : hydrogen gas = <NUM> : <NUM>. For example, if the carbon source gas is set to <NUM> sccm, then the hydrogen gas may be set to <NUM> sccm.

By controlling the plasma generator <NUM>, the plasma introduction unit <NUM>, and the magnetic field generation unit <NUM>, the sheet plasma P is generated in the chamber <NUM> by using the electric discharge gas such as argon gas as a working gas. When the mixed gas of the carbon source gas and the hydrogen gas is used as the raw material gas, a flow ratio among the carbon source gas, the hydrogen gas, and the electric discharge gas may be set to carbon source gas : hydrogen gas : electric discharge gas = <NUM> : <NUM> : <NUM>. For example, if the carbon source gas is set to <NUM> sccm and the hydrogen gas is set to <NUM> sccm, then the electric discharge gas may be set to <NUM> sccm. A pressure inside the chamber <NUM> may be set to <NUM> Pa, for example. A discharge current may be set to <NUM> A, for example.

The raw material gas is dissociated and excited by the sheet plasma P as the gas is passed through the sheet plasma P, and is directed to the carbon fiber material <NUM> as activated hydrocarbon molecules. Then, the carbon nanowalls <NUM> are formed into a substantially uniform coating on the surface of the continuous carbon fiber <NUM> of the carbon fiber material <NUM> for example. The sheet plasma P is high-density plasma and can therefore increase the formation rate of the carbon nanowalls <NUM>. Moreover, the sheet plasma P is formed into the sheet-shaped plasma, and can therefore form the carbon nanowalls <NUM> more uniformly even when a width direction (an orthogonal direction to a traveling direction) of the carbon fiber material <NUM> is large in the case where the carbon fiber material <NUM> is formed from the multiple continuous carbon fibers <NUM> as shown in <FIG> or in the case where the carbon fiber material <NUM> is formed from the carbon fiber fabric as shown in <FIG>.

The winding step (S14) is a step of winding the carbon fiber material <NUM>, which is provided with the carbon nanowalls <NUM> on the surface of the continuous carbon fiber <NUM>, around the winding bobbin <NUM>. The carbon fiber material <NUM> provided with the carbon nanowalls <NUM> on the surface of the continuous carbon fiber <NUM> is guided by the winding pulley <NUM> and wound around the winding bobbin <NUM>.

The carbon fiber complex material <NUM> is manufactured as described above. According to the above-described method of manufacturing the carbon fiber complex material <NUM>, it is possible to form the carbon nanowalls <NUM> continuously on the surface of the continuous carbon fiber <NUM>. Note that although the above-described method of manufacturing the carbon fiber complex material <NUM> explains the case of forming the carbon nanowalls <NUM> by using the sheet plasma P, the plasma is not limited to the sheet plasma P in particular and a general plasma CVD apparatus can be used. As for the plasma CVD apparatus, it is possible to use any of plasma CVD apparatuses of a high-frequency capacitively coupled type (a parallel flat plate type), a high-frequency inductively coupled type, a microwave-excited type, and an ECR plasma type, for example.

Next, a description will be given of a case of applying the carbon fiber complex material <NUM> to the carbon fiber reinforced plastic composite material. When applying the carbon fiber complex material <NUM> to the carbon fiber reinforced plastic composite material, the carbon fiber complex material <NUM> may be used for a prepreg. The prepreg includes the carbon fiber complex material <NUM>, and a semicured resin layer made of a semicured resin and provided to the carbon fiber complex material <NUM>. The prepreg can be produced, for example, by impregnating the carbon fiber complex material <NUM> with the resin and then semicuring the impregnating resin. The semicuring is a state in the middle of an uncured state and a cured state, which is a state of a B-stage of the resin, for instance. The resin to impregnate the carbon fiber complex material <NUM> is not limited to a particular resin and epoxy resin, phenol resin, polyimide resin, polyester resin, and the like can be used, for instance. The carbon fiber reinforced plastic composite material may be formed, for example, by laminating such prepregs into a laminated body in a shape of a prescribed component and then curing the resin by applying heat and pressure to the laminated body in an autoclave or the like.

Meanwhile, the carbon fiber reinforced plastic composite material may be formed by RTM molding, VaRTM molding, and the like. The carbon fiber reinforced plastic composite material may be fabricated by forming the carbon fiber complex material <NUM> into a preform in a shape of a prescribed component, injecting the resin into this preform, and then curing the resin. Furthermore, the carbon fiber reinforced plastic composite material can also be formed by filament winding molding and the like.

<FIG> is a diagram showing a structure of a carbon fiber reinforced plastic composite material <NUM> using the carbon fiber complex material <NUM>. The carbon fiber reinforced plastic composite material <NUM> includes the carbon fiber complex material <NUM> and a matrix resin layer <NUM> made of a cured resin material and provided to the carbon fiber complex material <NUM>. Bonding strength between the continuous carbon fiber <NUM> and the matrix resin layer <NUM> can be improved by the anchoring effect attributed to the uneven structure formed of the carbon nanowalls <NUM>. In this way, the matrix resin layer <NUM> and the continuous carbon fiber <NUM> are kept from delamination at the interface therebetween. Thus, it is possible to suppress delamination at the time of forming the carbon fiber reinforced plastic composite material <NUM> and to improve mechanical characteristics of the carbon fiber reinforced plastic composite material <NUM>.

As described above, according to the carbon fiber complex material for the carbon fiber reinforced plastic composite material of this configuration, the carbon nanowalls are formed on the surface of the continuous carbon fiber of the carbon fiber material. Thus, the anchoring effect attributed to the uneven structure formed of the carbon nanowalls can increase adhesion between the continuous carbon fiber and the matrix resin layer when the carbon fiber reinforced plastic composite material is formed. Meanwhile, the carbon nanowalls are formed away from one another at intervals due to the self-organizing property, and are therefore kept from being entwined with one another unlike in the case of the carbon nanotubes. Hence, the uneven structure is more finely formed by the carbon nanowalls so that the adhesion between the continuous carbon fiber and the matrix resin layer can be further increased.

The method of manufacturing a carbon fiber complex material of the above-described configuration includes a feeding step of feeding a carbon fiber material formed from a continuous carbon fiber out of a feeding bobbin around which the carbon fiber material is wound, a carbon nanowall forming step of forming carbon nanowalls on a surface of the continuous carbon fiber of the carbon fiber material by heating the carbon fiber material fed out of the feeding bobbin to <NUM> or above and supplying a raw material gas containing a carbon source gas to cause a reaction in plasma, and a winding step of winding the carbon fiber material, which is provided with the carbon nanowalls on the surface of the continuous carbon fiber, around a winding bobbin. Accordingly, it is possible to form the carbon nanowalls continuously on the surface of the continuous carbon fiber of the carbon fiber material. Moreover, according to the method of manufacturing a carbon fiber complex material of the above-described configuration, the carbon nanowalls are formed on the surface of the continuous carbon fiber, and the method therefore does not need a catalyst unlike the case of forming the carbon nanotubes. Furthermore, in the case of forming the carbon nanotubes, a dispersion treatment for dispersing the carbon nanotubes is needed since the carbon nanotubes are apt to be entwined with one another. On the other hand, the carbon nanowalls are formed separately from one another thanks to the self-organizing property and therefore do not need such a dispersion treatment.

The manufacturing apparatus for a carbon fiber complex material having the above-described configuration includes an apparatus body provided with a chamber, a raw material gas supply unit configured to supply a raw material gas containing a carbon source gas to the chamber, a plasma generation unit configured to generate plasma in the chamber, a feeding bobbin around which a carbon fiber material formed from a continuous carbon fiber is wound, the feeding bobbin being configured to feed the carbon fiber material out, a winding bobbin configured to wind the carbon fiber material provided with carbon nanowalls on a surface of the continuous carbon fiber, and a heating unit located opposite to the plasma generated in the chamber while interposing the carbon fiber material in between and configured to heat the carbon fiber material. Accordingly, it is possible to form the carbon nanowalls continuously on the surface of the continuous carbon fiber of the carbon fiber material.

Next, a second embodiment of this disclosure will be described below in detail with reference to the drawing. <FIG> is a flowchart showing a configuration of a method of manufacturing the carbon fiber complex material <NUM>. The method of manufacturing a carbon fiber complex material of the second embodiment is different from the method of manufacturing the carbon fiber complex material <NUM> of the first embodiment mainly in that the method of the second embodiment includes a surface activation treatment step (S22). Note that the same constituents are denoted by the same reference signs and detailed explanations thereof will be omitted.

The method of manufacturing the carbon fiber complex material <NUM> includes a feeding step (S20), a surface activation treatment step (S22), a carbon nanowall forming step (S24) to be carried out subsequent to the surface activation treatment step (S22), and a winding step (S26). The manufacturing apparatus <NUM> for the carbon fiber complex material <NUM> shown in <FIG> can be used in the method of manufacturing the carbon fiber complex material <NUM>. Next, a description will be given of the method of manufacturing the carbon fiber complex material <NUM> when using the manufacturing apparatus <NUM> for the carbon fiber complex material <NUM> shown in <FIG>.

The feeding step (S20) is a step of feeding the carbon fiber material <NUM> formed from the continuous carbon fiber <NUM> out of the feeding bobbin <NUM> around which the carbon fiber material <NUM> is wound. The feeding step (S20) can be carried out in the same way as the feeding step (S10). The fed carbon fiber material <NUM> is guided and turned to the x-axis direction by the feeding pulley <NUM>. The turned carbon fiber material <NUM> is exposed to the sheet plasma P as described later.

When the sizing agent or the like adheres to the continuous carbon fiber <NUM>, the sizing agent or the like may be removed by heating the carbon fiber material <NUM> with the preheating unit 78b. By removing the sizing agent or the like adhering to the continuous carbon fiber <NUM> in advance, it is possible to further activate the surface of the continuous carbon fiber <NUM> in the surface activation treatment step (S22).

The surface activation treatment step (S22) is a step of activating the surface of the continuous carbon fiber <NUM> by conducting a surface activation treatment while bringing the carbon fiber material <NUM> fed out of the feeding bobbin <NUM> into a reaction in the plasma by supplying a surface activation treatment gas containing an inert gas but no carbon source gas (while nevertheless allowing contamination with the carbon source gas at an inevitable level as it may occur due to diffusion through a slit to be described later) before formation of the carbon nanowalls <NUM> on the surface of the continuous carbon fiber <NUM>.

The adhesion between the continuous carbon fiber <NUM> and the carbon nanowalls <NUM> can be improved by activating the surface of the continuous carbon fiber <NUM>. To be more precise, when the continuous carbon fiber <NUM> is brought into the reaction in the plasma, the plasma collides with the surface of the continuous carbon fiber <NUM> whereby surface energy is increased. In this way, the surface of the continuous carbon fiber <NUM> is activated and bonded with the carbon nanowalls <NUM> more easily. As a consequence, the adhesion between the continuous carbon fiber <NUM> and the carbon nanowalls <NUM> is improved.

The carbon fiber material <NUM> guided and turned to the x-axis direction by the feeding pulley <NUM> is exposed to the sheet plasma P. To be more precise, the sheet plasma P is generated by supplying the surface activation treatment gas containing the inert gas such as argon gas but containing no carbon source gas into the chamber <NUM>. The inert gas is supplied from the electric discharge gas supply unit <NUM> as the electric discharge gas for generating the plasma. A flow rate of the inert gas may be set to <NUM> sccm, for example. The surface activation treatment gas may further contain hydrogen gas. When the surface activation treatment gas contains hydrogen gas, the raw material gas supply unit <NUM> may supply only the hydrogen gas. A flow ratio between the inert gas and the hydrogen gas may be set as inert gas : hydrogen gas = <NUM> : <NUM>. For example, if the flow rate of the inert gas is set to <NUM> sccm, then the flow rate of the hydrogen gas may be set to <NUM> sccm.

As for conditions to generate the plasma, it is possible to set the pressure inside the chamber <NUM> to <NUM> Pa and to set the discharge current to <NUM> A, for example. The conditions to generate the plasma may be set to the same as or different from conditions to generate the plasma in the carbon nanowall forming step (S24). When the carbon fiber material <NUM> is exposed to the sheet plasma P, the plasma collides with the surface of the continuous carbon fiber <NUM> whereby the surface energy is increased. Thus, the surface of the continuous carbon fiber <NUM> is activated.

Here, when the carbon fiber material <NUM> is exposed to the sheet plasma P, the carbon fiber material <NUM> may be heated to <NUM> or above, for example, or to a range from <NUM> to <NUM> inclusive by using the heating unit body 78a.

The carbon nanowall forming step (S24) is a step of forming the carbon nanowalls <NUM> on the surface of the continuous carbon fiber <NUM> of the carbon fiber material <NUM> by heating the carbon fiber material <NUM> subjected to the surface activation treatment to <NUM> or above and supplying the raw material gas containing the carbon source gas to cause a reaction in the plasma. The carbon nanowall forming step (S24) can be carried out in the same way as the carbon nanowall forming step (S12).

The raw material gas is dissociated and excited by the sheet plasma P and the activated hydrocarbon molecules are directed to the carbon fiber material <NUM> subjected to the surface activation treatment. Then, the carbon nanowalls <NUM> are formed on the surface of the continuous carbon fiber <NUM> subjected to the surface activation. Since the surface of the continuous carbon fiber <NUM> is activated, the continuous carbon fiber <NUM> is bonded with the carbon nanowalls <NUM> more easily. In this way, it is possible to further improve the adhesion between the continuous carbon fiber <NUM> and the carbon nanowalls <NUM>. The formation of the carbon nanowalls <NUM> may be carried out continuously to the surface activation treatment on the carbon fiber material <NUM>.

The winding step (S26) is a step of winding the carbon fiber material <NUM>, which is provided with the carbon nanowalls <NUM> on the surface of the continuous carbon fiber <NUM>, around the winding bobbin <NUM>. The winding step (S26) can be carried out in the same way as the winding step (S14). The carbon fiber material <NUM> provided with the carbon nanowalls <NUM> on the surface of the continuous carbon fiber <NUM> is guided by the winding pulley <NUM> and wound around the winding bobbin <NUM>.

Here, the chamber <NUM> is evacuated by using the vacuum pump <NUM> after the carbon nanowall forming step (S24) or the winding step (S26) so as to exhaust the raw material gas remaining in the chamber <NUM>. This makes it possible to inhibit the carbon source gas contained in the raw material gas from being mixed with the surface activation treatment gas when subjecting a carbon fiber material <NUM> fed newly to the surface activation treatment. Then, after the raw material gas remaining in the chamber <NUM> is exhausted, the newly fed carbon fiber material <NUM> undergoes the surface activation treatment step (S22) and the carbon nanowall forming step (S24).

According to the above-described configuration, the method includes the surface activation treatment step of activating the surface of the continuous carbon fiber by subjecting the carbon fiber material fed out of the feeding bobbin to the surface activation treatment by bringing the continuous carbon fiber to the reaction in the plasma while supplying the surface activation treatment gas containing the inert gas but no carbon source gas before formation of the carbon nanowalls on the surface of the continuous carbon fiber. Thus, it is possible to further improve the adhesion between the continuous carbon fiber and the carbon nanowalls.

Next, a third embodiment of this disclosure will be described in detail with reference to the drawing. The third embodiment involves a different configuration of the manufacturing apparatus for the carbon fiber complex material <NUM> from that of the second embodiment. <FIG> is a diagram showing a configuration of a manufacturing apparatus <NUM> for the carbon fiber complex material <NUM>. <FIG> sets up the XYZ Cartesian coordinate system and positional relations among respective constituents will be described with reference to the XYZ Cartesian coordinate system. Moreover, a predetermined direction in a horizontal plane is defined as x-axis direction, a direction orthogonal to the x-axis direction within the horizontal plane is defined as a y-axis direction, and a direction (a vertical direction) orthogonal to the x-axis direction and to the y-axis direction is defined as z-axis direction. Note that the same constituents as above are denoted by the same reference signs and detailed explanations thereof will be omitted.

The manufacturing apparatus <NUM> for the carbon fiber complex material <NUM> includes an apparatus body <NUM> provided with a chamber <NUM>. The chamber <NUM> includes a first sub-chamber <NUM> in which the carbon fiber material <NUM> formed from the continuous carbon fiber <NUM> is subjected to the surface activation treatment. The first sub-chamber <NUM> is provided on the left side in the x-axis direction of the chamber <NUM>. The chamber <NUM> includes a second sub-chamber <NUM> in which the carbon nanowalls <NUM> are formed on the surface of the continuous carbon fiber <NUM> of the carbon fiber material <NUM> subjected to the surface activation treatment. The second sub-chamber <NUM> is provided on the right side in the x-axis direction of the chamber <NUM>.

The chamber <NUM> includes a partition wall <NUM> for partitioning the first sub-chamber <NUM> and the second sub-chamber <NUM>. The partition wall <NUM> is formed to extend in the z-axis direction of the chamber <NUM>. The partition wall <NUM> makes it possible to suppress mixture of the surface activation treatment gas to be supplied to the first sub-chamber <NUM> with the raw material gas to be supplied to the second sub-chamber <NUM>. In this way, the surface activation treatment and the formation of the carbon nanowalls can be carried out at the same time. The partition wall <NUM> includes a slit <NUM> that allows insertion of the carbon fiber material <NUM> subjected to the surface activation treatment. The slit <NUM> is provided on a lower side in the z-axis direction. The slit <NUM> may be formed into a rectangular shape, for example. The slit <NUM> may be formed thin in order to inhibit the raw material gas supplied to the second sub-chamber <NUM> from flowing into the first sub-chamber <NUM>.

The chamber <NUM> includes an exhaust pipe <NUM> to exhaust a gas in the first sub-chamber <NUM>. The exhaust pipe <NUM> connects with the inside of the first sub-chamber <NUM>. The exhaust pipe <NUM> is connected to a vacuum pump <NUM> and is configured to be capable of evacuating the inside of the first sub-chamber <NUM>. The exhaust pipe <NUM> is provided with a valve mechanism (not shown) such as an electromagnetic valve for exhausting or stopping the gas in the first sub-chamber <NUM>.

The chamber <NUM> includes an exhaust pipe <NUM> to exhaust a gas in the second sub-chamber <NUM>. The exhaust pipe <NUM> connects with the inside of the second sub-chamber <NUM>. The exhaust pipe <NUM> is connected to a vacuum pump <NUM> and is configured to be capable of evacuating the inside of the second sub-chamber <NUM>. The exhaust pipe <NUM> is provided with a valve mechanism (not shown) such as an electromagnetic valve for exhausting or stopping the gas in the second sub-chamber <NUM>.

A surface activation treatment gas supply unit <NUM> is provided to the apparatus body <NUM> and has a function to supply the surface activation treatment gas used for subjecting the carbon fiber material <NUM> to the surface activation treatment in the first sub-chamber <NUM>. The surface activation treatment gas supply unit <NUM> is provided outside the chamber <NUM> and includes storage gas tanks <NUM>, <NUM> storing the surface activation treatment gas, and a supply pipe <NUM> connected to the storage gas tanks <NUM>, <NUM> and to the chamber <NUM> for supplying the surface activation treatment gas from the storage gas tanks <NUM>, <NUM> to the first sub-chamber <NUM>.

The supply pipe <NUM> is provided on an upper side in the z-axis direction of the first sub-chamber <NUM> and extends from the outside to the inside of the chamber <NUM>. Moreover, the supply pipe <NUM> projects from an inner peripheral surface of the first sub-chamber <NUM> to the inside thereof. The supply pipe <NUM> is provided with a valve mechanism (not shown) such as an electromagnetic valve for supplying or stopping the surface activation treatment gas.

An inert gas such as argon is stored in the storage gas tank <NUM>. The inert gas has a function as the electric discharge gas used for generating the plasma. Hydrogen gas is stored in the storage gas tank <NUM>. When hydrogen gas is supplied in addition to the inert gas, these gases may be supplied as a mixed gas or supplied separately from each other.

An electric discharge gas supply unit <NUM> is provided to the apparatus body <NUM> and has a function to supply the electric discharge gas used for generating the plasma to the second sub-chamber <NUM>. The electric discharge gas supply unit <NUM> is provided outside the chamber <NUM> and includes a storage gas tank <NUM> storing the electric discharge gas, and a supply pipe <NUM> connected to the storage gas tank <NUM> and to the second sub-chamber <NUM> for supplying the electric discharge gas from the storage gas tank <NUM> to the second sub-chamber <NUM>.

The supply pipe <NUM> is provided on an upper side in the z-axis direction of the second sub-chamber <NUM> and extends from the outside to the inside of the second sub-chamber <NUM>. Moreover, the supply pipe <NUM> projects from an inner peripheral surface of the second sub-chamber <NUM> to the inside thereof. The supply pipe <NUM> is provided with a valve mechanism (not shown) such as an electromagnetic valve for supplying or stopping the electric discharge gas. An inert gas such as argon gas can be used for the electric discharge gas.

A raw material gas supply unit <NUM> is provided to the apparatus body <NUM> and has a function to supply the raw material gas for forming the carbon nanowalls <NUM> to the second sub-chamber <NUM>. The raw material gas supply unit <NUM> is provided outside the chamber <NUM> and includes storage gas tanks <NUM>, <NUM> storing the raw material gas, and a supply pipe <NUM> connected to the storage gas tanks <NUM>, <NUM> and to the second sub-chamber <NUM> for supplying the raw materials gas from the storage gas tanks <NUM>, <NUM> to the second sub-chamber <NUM>.

The supply pipe <NUM> is provided on the upper side in the z-axis direction of the second sub-chamber <NUM> and extends from the outside to the inside of the second sub-chamber <NUM>. Moreover, the supply pipe <NUM> projects from the inner peripheral surface of the second sub-chamber <NUM> to the inside thereof. The supply pipe <NUM> is provided with a valve mechanism (not shown) such as an electromagnetic valve for supplying or stopping the raw material gas.

The carbon source gas such as a hydrocarbon gas including methane (CH<NUM>), ethane (C<NUM>H<NUM>), ethylene (C<NUM>H<NUM>), acetylene (C<NUM>H<NUM>), and mixtures thereof is stored in the storage gas tank <NUM>. Hydrogen gas is stored in the storage gas tank <NUM>. When hydrogen gas is supplied in addition to the carbon source gas, these gases may be supplied as a mixed gas or supplied separately from each other.

A first plasma generator <NUM> is provided to the apparatus body <NUM> and has a function to generate plasma P1 in the first sub-chamber <NUM>. The first plasma generator <NUM> is provided on a lower side in the z-axis direction of the first sub-chamber <NUM>. The first plasma generator <NUM> is connected to a plasma power source (not shown). The first plasma generator <NUM> can be formed from a general plasma CVD apparatus. As for the plasma CVD apparatus, it is possible to use any of the plasma CVD apparatuses of the high-frequency capacitively coupled type (parallel flat plate type), the high-frequency inductively coupled type, the microwave-excited type, and the ECR plasma type, for example.

A second plasma generator <NUM> is provided to the apparatus body <NUM> and has a function to generate plasma P2 in the second sub-chamber <NUM>. The second plasma generator <NUM> is provided on a lower side in the z-axis direction of the second sub-chamber <NUM>. The second plasma generator <NUM> is connected to a plasma power source (not shown). As with the first plasma generator <NUM>, the second plasma generator <NUM> can be formed from a general plasma CVD apparatus.

A transport unit <NUM> to transport the carbon fiber material <NUM> is provided to the chamber <NUM>. The transport unit <NUM> includes a feeding bobbin <NUM>, a winding bobbin <NUM>, a feeding pulley <NUM>, and a winding pulley <NUM>. Moreover, the transport unit <NUM> includes a driving mechanism <NUM> provided to the apparatus body <NUM> such as a motor for transmitting a rotary driving force to the winding bobbin <NUM>.

The feeding bobbin <NUM> is a bobbin provided to the first sub-chamber <NUM>. The carbon fiber material <NUM> is wound around the feeding bobbin <NUM> and the feeding bobbin <NUM> is formed to be capable of feeding the carbon fiber material <NUM> out. The feeding bobbin <NUM> is located on the left side in the x-axis direction of the first sub-chamber <NUM>.

The winding bobbin <NUM> is a bobbin provided to the second sub-chamber <NUM>. The winding bobbin <NUM> is formed to be capable of winding the carbon fiber material <NUM> provided with the carbon nanowalls <NUM> on the surface of the continuous carbon fiber <NUM>. The winding bobbin <NUM> is located on the right side in the x-axis direction of the second sub-chamber <NUM>. The rotary driving force is transmitted from the driving mechanism <NUM> such as the motor to the winding bobbin <NUM>. In other words, the carbon fiber material <NUM> is transported in a state of receiving a tensile force. Here, the transport unit <NUM> may include a driving mechanism such as a motor for transmitting a rotary driving force to the feeding bobbin <NUM>. The tensile force to be applied to the carbon fiber material <NUM> is adjustable by controlling a feeding speed of the feeding bobbin <NUM> and a winding speed of the winding bobbin <NUM>, for example.

The feeding pulley <NUM> is provided to the first sub-chamber <NUM>. The feeding pulley <NUM> is located on a lower side in the z-axis direction of the feeding bobbin <NUM>. The winding pulley <NUM> is provided to the second sub-chamber <NUM>. The winding pulley <NUM> is located on a lower side in the z-axis direction of the winding bobbin <NUM>.

The carbon fiber material <NUM> fed out of the feeding bobbin <NUM> is turned to the x-axis direction by the feeding pulley <NUM>. The carbon fiber material <NUM> turned to the x-axis direction is exposed to the plasma P1 and subjected to the surface activation treatment. The carbon fiber material <NUM> subjected to the surface activation treatment is passed through the slit <NUM> in the partition wall <NUM> and transported into the second sub-chamber <NUM>. The carbon fiber material <NUM> subjected to the surface activation treatment is exposed to the plasma P2, whereby the carbon nanowalls <NUM> are formed on the surface of the continuous carbon fiber <NUM> subjected to the surface activation. The carbon fiber material <NUM> provided with the carbon nanowalls <NUM> on the surface of the continuous carbon fiber <NUM> is turned to the z-axis direction by the winding pulley <NUM> and wound around the winding bobbin <NUM>.

A first heating unit <NUM> is provided to the first sub-chamber <NUM> and has a function to heat the carbon fiber material <NUM>. The first heating unit <NUM> is provided on the lower side in the z-axis direction of the first sub-chamber <NUM> and located opposite to the first plasma generator <NUM> while interposing the carbon fiber material <NUM> in between. The first heating unit <NUM> is configured to be capable of removing the sizing agent or the like adhering to the continuous carbon fiber <NUM> by heating the carbon fiber material <NUM>. Moreover, the first heating unit <NUM> can heat the carbon fiber material <NUM> in the state where the carbon fiber material <NUM> is exposed to the plasma P1. The first heating unit <NUM> can heat the carbon fiber material <NUM> to <NUM> or above. The first heating unit <NUM> can be formed from a heater or the like.

A second heating unit <NUM> is provided to the second sub-chamber <NUM> and has a function to heat the carbon fiber material <NUM> subjected to the surface activation treatment. The second heating unit <NUM> is provided on the lower side in the z-axis direction of the second sub-chamber <NUM> and located opposite to the second plasma generator <NUM> while interposing the carbon fiber material <NUM> subjected to the surface activation treatment in between. The second heating unit <NUM> may be located on the lower side in the z-axis direction of the supply pipe <NUM> so as to facilitate the formation of the carbon nanowalls <NUM>. The second heating unit <NUM> can heat the carbon fiber material <NUM> subjected to the surface activation treatment up to <NUM> or above, or in the range from <NUM> to <NUM>. The second heating unit <NUM> can be formed from a heater or the like.

A control unit (not shown) has a function to control the surface activation treatment gas supply unit <NUM>, the electric discharge gas supply unit <NUM>, the raw material gas supply unit <NUM>, the first plasma generator <NUM>, the second plasma generator <NUM>, the first heating unit <NUM>, the second heating unit <NUM>, the driving mechanism <NUM> for the winding bobbin <NUM>, and the like. The control unit (not shown) can conduct or stop the introduction of the surface activation treatment gas to the first sub-chamber <NUM> by controlling the surface activation treatment gas supply unit <NUM>. The control unit (not shown) can conduct or stop the introduction of the electric discharge gas to the second sub-chamber <NUM> by controlling the electric discharge gas supply unit <NUM>. The control unit (not shown) can conduct or stop the introduction of the raw material gas to the second sub-chamber <NUM> by controlling the raw material gas supply unit <NUM>. The control unit (not shown) can conduct or stop the generation of the plasma P1 in the first sub-chamber <NUM> by controlling the first plasma generator <NUM>. The control unit (not shown) can conduct or stop the generation of the plasma P2 in the second sub-chamber <NUM> by controlling the second plasma generator <NUM>. The control unit (not shown) can adjust the start and stop of winding the carbon fiber material <NUM> around, the winding speed of the carbon fiber material <NUM>, and the like by controlling the driving mechanism <NUM> for the winding bobbin <NUM>. The control unit (not shown) can be constructed by using a general computer system and the like.

Next, a description will be given of the method of manufacturing the carbon fiber complex material <NUM> by using the manufacturing apparatus <NUM>.

In the feeding step (S20), the carbon fiber material <NUM> fed out of the feeding bobbin <NUM> is guided and turned to the x-axis direction by the feeding pulley <NUM>. When the sizing agent or the like adheres to the continuous carbon fiber <NUM>, the sizing agent or the like may be removed by heating the carbon fiber material <NUM> with the first heating unit <NUM>.

In the surface activation treatment step (S22), the carbon fiber material <NUM> turned to the x-axis direction is exposed to the plasma P1 and subjected to the surface activation treatment. To be more precise, the surface activation treatment gas containing the inert gas such as argon gas but no carbon source gas is supplied from the surface activation treatment gas supply unit <NUM> to the first sub-chamber <NUM>. The flow rate of the inert gas may be set to <NUM> sccm. The surface activation treatment gas may further contain hydrogen gas. The flow ratio between the inert gas and the hydrogen gas may be set as inert gas : hydrogen gas = <NUM> : <NUM>. For example, if the flow rate of the inert gas is set to <NUM> sccm, then the flow rate of the hydrogen gas may be set to <NUM> sccm.

Thereafter, the plasma P1 is generated in the first sub-chamber <NUM> by activating the first plasma generator <NUM>. As for conditions to generate the plasma, it is possible to set the pressure inside the first sub-chamber <NUM> to <NUM> Pa and to set the discharge current to <NUM> A, for example. When the carbon fiber material <NUM> is exposed to the plasma P1, the plasma P1 collides with the surface of the continuous carbon fiber <NUM> and the surface energy is increased. Thus, the surface of the continuous carbon fiber <NUM> is activated. Alternatively, the surface activation treatment may be conducted by heating the carbon fiber material <NUM> to the <NUM> or above, for example, with the first heating unit <NUM> in the state of exposing the carbon fiber material <NUM> to the plasma P1.

The carbon fiber material <NUM> subjected to the surface activation treatment is passed through the slit <NUM> in the partition wall <NUM> and transported to the second sub-chamber <NUM>. Here, the pressure in the first sub-chamber <NUM> may be set equal to or higher than the pressure in the second sub-chamber <NUM>. In this way, it is possible to inhibit the raw material gas supplied to the second sub-chamber <NUM> from flowing into the first sub-chamber <NUM> through the slit <NUM>.

In the carbon nanowall forming step (S24), the electric discharge gas is supplied from the electric discharge gas supply unit <NUM> to the second sub-chamber <NUM>. The plasma P2 is generated in the second sub-chamber <NUM> by activating the second plasma generator <NUM>. As for conditions to generate the plasma, it is possible to set the pressure inside the second sub-chamber <NUM> to <NUM> Pa and to set the discharge current to <NUM> A, for example.

Then, the raw material gas containing the carbon source gas is supplied from the raw material gas supply unit <NUM> to the second sub-chamber <NUM>. The raw material gas may contain hydrogen gas. The flow ratio between the carbon source gas and the hydrogen gas may be set to carbon source gas : hydrogen gas = <NUM>: <NUM>. Meanwhile, the flow ratio among the carbon source gas, the hydrogen gas, and the electric discharge gas may be set to carbon source gas : hydrogen gas : electric discharge gas = <NUM> : <NUM> : <NUM>. For example, if the carbon source gas is set to <NUM> sccm and the hydrogen gas is set to <NUM> sccm, then the electric discharge gas may be set to <NUM> sccm. The carbon fiber material <NUM> subjected to the surface activation treatment is heated to <NUM> or above, or in the range from <NUM> to <NUM> inclusive with the second heating unit <NUM>. The raw material gas is dissociated and excited by the plasma P2, and is directed to the carbon fiber material <NUM> subjected to the surface activation treatment as the activated hydrocarbon molecules. Then, the carbon nanowalls <NUM> are formed on the surface of the continuous carbon fiber <NUM> subjected to the surface activation.

In the winding step (S26), the carbon fiber material <NUM> provided with the carbon nanowalls <NUM> on the surface of the continuous carbon fiber <NUM> is guided to the z-axis direction by the winding pulley <NUM> and wound around the winding bobbin <NUM>.

Meanwhile, when the carbon nanowalls <NUM> are formed on the surface of the continuous carbon fiber <NUM> subjected to the surface activation in the second sub-chamber <NUM>, it is possible to subject the newly fed carbon fiber material <NUM> to the surface activation treatment in the first sub-chamber <NUM>. Since the first sub-chamber <NUM> and the second sub-chamber <NUM> are separated from each other by the partition wall <NUM>, it is possible to carry out the surface activation treatment on the carbon fiber material <NUM> and the formation of the carbon nanowalls <NUM> at the same time.

According to the manufacturing apparatus for a carbon fiber complex material having the above-described configuration, the surface of the continuous carbon fiber can be activated by subjecting the carbon fiber material that is fed out of the feeding bobbin to the surface activation treatment by bringing the carbon fiber material into the reaction in the plasma while supplying the surface activation treatment gas containing the inert gas but no carbon source gas before formation of the carbon nanowalls on the surface of the continuous carbon fiber. Thus, it is possible to carry out the surface activation treatment on the carbon fiber material and the formation of the carbon nanowalls continuously.

According to the manufacturing apparatus for a carbon fiber complex material having the above-described configuration, it is possible to carry out the surface activation treatment on the carbon fiber material and the formation of the carbon nanowalls at the same time, and thus to improve productivity of the carbon fiber complex material.

An adhesion test of the carbon nanowalls was carried out.

A continuous carbon fiber was used as a carbon fiber material. The above-described manufacturing apparatus <NUM> for the carbon fiber complex material <NUM> shown in <FIG> was used as the manufacturing apparatus for a carbon fiber complex material. First, the sizing material and the like adhering to the continuous carbon fiber were removed by heating the carbon fiber material.

Next, the carbon nanowalls were formed on the surface of the continuous carbon fiber with the sizing agent and the like removed. First, the carbon fiber material was heated to the range from <NUM> to <NUM> inclusive. Then, the raw material gas was supplied into the chamber. A mixed gas of methane gas and hydrogen gas was used as the raw material gas. The flow rate of the methane gas was set to <NUM> sccm. The flow rate of the hydrogen gas was set to <NUM> sccm. The sheet plasma was generated in the chamber while using argon gas as the electric discharge gas. The flow rate of the argon gas was set to <NUM> sccm. The pressure inside the chamber was set to <NUM> Pa. The discharge current was set to <NUM> A. Then, the carbon nanowalls were formed into a coating on the surface of the continuous carbon fiber.

The continuous carbon fiber with the sizing agent and the like removed before formation of the carbon nanowalls and the continuous carbon fiber on which the carbon nanowalls were formed into the coating were subjected to observation of microstructures by using a scanning electron microscope (SEM). <FIG> is a photograph showing a result of observation of microstructures on the surface of the continuous carbon fiber before formation of the carbon nanowalls. <FIG> is a photograph showing a result of observation of microstructures on the surface of the continuous carbon fiber on which the carbon nanowalls were formed into the coating. The formation of the carbon nanowalls into the coating on the surface of the continuous carbon fiber was confirmed as shown in the photograph of <FIG>. A film thickness of the coating formed from the carbon nanowalls was about <NUM>.

Next, the continuous carbon fiber before formation of the carbon nanowalls and the continuous carbon fiber on which the carbon nanowalls were formed into the coating were subjected to an evaluation test on adhesion at an interface with epoxy resin. A micro-droplet method was used in the evaluation test on the adhesion at the interface. A resin particle made of epoxy resin was attached to each of the continuous carbon fiber before formation of the carbon nanowalls and the continuous carbon fiber on which the carbon nanowalls were formed into the coating, then each of the continuous carbon fibers was pulled out and subjected to a measurement of interface shear strength. The interface shear strength was determined from an average value of five test samples.

Assuming that the interface shear strength of the continuous carbon fiber before formation of the carbon nanowalls was <NUM>, the interface shear strength of about <NUM> times as large as the foregoing was obtained from the continuous carbon fiber on which the carbon nanowalls were formed into the coating. This result revealed that the formation of the carbon nanowalls on the surface of the continuous carbon fiber increased the adhesion to the resin at the interface and made it possible to improve the adhesion to the matrix resin layer when the carbon fiber reinforced plastic composite material was formed.

The surface of the continuous carbon fiber on which the carbon nanowalls were formed into the coating and after being pulled out of the resin particle was subjected to observation of microstructures by using the scanning electron microscope (SEM). <FIG> is a photograph showing a result of observation of microstructures on the surface of the continuous carbon fiber on which the carbon nanowalls were formed into the coating and after being pulled out of the resin particle. As shown in the photograph of <FIG>, numerous carbon nanowalls remained on the surface of the continuous carbon fiber. This revealed that the adhesion between the continuous carbon fiber and the carbon nanowalls was also high.

Claim 1:
A carbon fiber complex material (<NUM>) for a carbon fiber reinforced plastic composite material, comprising:
a carbon fiber material (<NUM>) formed from a continuous carbon fiber (<NUM>); and
carbon nanowalls (<NUM>) formed on a surface of the continuous carbon fiber (<NUM>), wherein a length of the continuous carbon fiber (<NUM>) is equal to or above <NUM>.