JP4512583B2 - Method for producing carbon fiber composite metal material - Google Patents

Description

The present invention relates to a method of manufacturing the carbon nanofibers uniformly dispersed carbon fiber-metal composite materials.

  In general, carbon nanofibers are fillers that are difficult to disperse in a matrix. The method for producing a carbon fiber composite material previously proposed by the present inventors has improved the dispersibility of carbon nanofibers, which has been considered difficult until now, and was able to uniformly disperse carbon nanofibers in an elastomer ( For example, see Patent Document 1). According to such a method for producing a carbon fiber composite material, an elastomer and carbon nanofibers are kneaded, and dispersibility of carbon nanofibers having high cohesiveness is improved by shearing force. More specifically, when the elastomer and the carbon nanofiber are mixed, the viscous elastomer penetrates into the carbon nanofiber, and a specific part of the elastomer has high activity of the carbon nanofiber due to chemical interaction. In this state, when a strong shearing force is applied to a mixture of an elastomer having high molecular mobility (elasticity) and carbon nanofibers, the carbon nanofibers are deformed as the elastomer is deformed. The fibers also moved, and the aggregated carbon nanofibers were separated and dispersed in the elastomer by the restoring force of the elastomer due to elasticity after shearing.

  Furthermore, the present inventors proposed a method for producing a carbon fiber composite metal material in which carbon nanofibers are uniformly dispersed in another matrix, for example, a metal matrix, using a carbon fiber composite material in which carbon nanofibers are uniformly dispersed. (For example, see Patent Document 2).

Thus, by improving the dispersibility of the carbon nanofibers in the matrix, expensive carbon nanofibers can be used efficiently as fillers for composite materials.
JP 2005-97525 A JP-A-2005-97534

An object of the present invention is to provide a method for producing carbon nanofibers uniformly dispersed carbon fiber-metal composite materials.

One aspect of the method for producing a carbon fiber composite metal material according to the present invention is:
The molecular weight of the elastomer is reduced by masticating an elastomer having a first spin-spin relaxation time (T2n) of 100 to 3000 μsec in an uncrosslinked product, measured at 30 ° C. by the Hahn echo method using pulsed NMR. And (a) obtaining a liquid elastomer,
Mixing the elastomer obtained in the step (a) with carbon nanofibers having an average diameter of 0.5 to 500 nm to obtain a mixture (b);
Increasing the molecular weight of the elastomer in the mixture obtained in step (b) to obtain a rubbery elastic mixture (c);
Kneading the mixture of rubber-like elastic bodies obtained in the step (c), and dispersing the carbon nanofibers in the elastomer by a shearing force to obtain a carbon fiber composite material; and
The carbon fiber composite material obtained in the step (d) is heated to decompose and vaporize an elastomer to obtain a carbon-based material, and then the metal material is inserted into voids of the carbon-based material formed by decomposing and vaporizing the elastomer. was allowed to permeate, the step (e) of the elastomer of the carbon fiber composite material to replace the metallic material to obtain a carbon fiber-metal composite material,
including.
One aspect of the method for producing a carbon fiber composite metal material according to the present invention is:
The molecular weight of the elastomer is reduced by masticating an elastomer having a first spin-spin relaxation time (T2n) of 100 to 3000 μsec in an uncrosslinked product, measured at 30 ° C. by the Hahn echo method using pulsed NMR. And (a) obtaining a liquid elastomer,
Mixing the elastomer obtained in the step (a) with carbon nanofibers having an average diameter of 0.5 to 500 nm to obtain a mixture (b);
Increasing the molecular weight of the elastomer in the mixture obtained in step (b) to obtain a rubbery elastic mixture (c);
Kneading the mixture of rubber-like elastic bodies obtained in the step (c), and dispersing the carbon nanofibers in the elastomer by a shearing force to obtain a carbon fiber composite material; and
After mixing the carbon fiber composite material obtained in the step (d) and the particles of the metal material, powder molding is performed, and the elastomer in the carbon fiber composite material is replaced with the metal material, thereby carbon fiber composite metal. Obtaining a material (e);
including.
One aspect of the method for producing a carbon fiber composite metal material according to the present invention is:
The molecular weight of the elastomer is reduced by masticating an elastomer having a first spin-spin relaxation time (T2n) of 100 to 3000 μsec in an uncrosslinked product, measured at 30 ° C. by the Hahn echo method using pulsed NMR. And (a) obtaining a liquid elastomer,
Mixing the elastomer obtained in the step (a) with carbon nanofibers having an average diameter of 0.5 to 500 nm to obtain a mixture (b);
Increasing the molecular weight of the elastomer in the mixture obtained in step (b) to obtain a rubbery elastic mixture (c);
Kneading the mixture of rubber-like elastic bodies obtained in the step (c), and dispersing the carbon nanofibers in the elastomer by a shearing force to obtain a carbon fiber composite material; and
Including
During the steps (a) to (d), particles of the metal material are dispersed in an elastomer,
The carbon fiber composite material containing particles of the metal material obtained in the step (d) is powder-molded, and the elastomer in the carbon fiber composite material is replaced with a metal material to obtain a carbon fiber composite metal material. (E) is further included.
One aspect of the method for producing a carbon fiber composite metal material according to the present invention is:
The molecular weight of the elastomer is reduced by masticating an elastomer having a first spin-spin relaxation time (T2n) of 100 to 3000 μsec in an uncrosslinked product, measured at 30 ° C. by the Hahn echo method using pulsed NMR. And (a) obtaining a liquid elastomer,
Mixing the elastomer obtained in the step (a) with carbon nanofibers having an average diameter of 0.5 to 500 nm to obtain a mixture (b);
Increasing the molecular weight of the elastomer in the mixture obtained in step (b) to obtain a rubbery elastic mixture (c);
Kneading the mixture of rubber-like elastic bodies obtained in the step (c), and dispersing the carbon nanofibers in the elastomer by a shearing force to obtain a carbon fiber composite material; and
Replacing the elastomer in the carbon fiber composite material obtained in the step (d) with a metal material to obtain a carbon fiber composite metal material (e);
including.
One aspect of the method for producing a carbon fiber composite metal material according to the present invention is:
The molecular weight of the elastomer is reduced by masticating an elastomer having a first spin-spin relaxation time (T2n) of 100 to 3000 μsec in an uncrosslinked product, measured at 30 ° C. by the Hahn echo method using pulsed NMR. And (a) obtaining a liquid elastomer,
Mixing the elastomer obtained in the step (a) with carbon nanofibers having an average diameter of 0.5 to 500 nm to obtain a mixture (b);
Increasing the molecular weight of the elastomer in the mixture obtained in step (b) to obtain a rubbery elastic mixture (c);
Kneading the mixture of rubber-like elastic bodies obtained in the step (c), and dispersing the carbon nanofibers in the elastomer by a shearing force to obtain a carbon fiber composite material; and
The carbon fiber composite material obtained in the step (d) is infiltrated with a molten metal material, and the elastomer in the carbon fiber composite material is replaced with a metal material to obtain a carbon fiber composite metal material ( e) and
including.

  According to the method for producing a carbon fiber composite metal material according to the present invention, by reducing the viscosity of the elastomer before mixing the elastomer and the carbon nanofiber in the step (a), the carbon nanofiber is contained in the elastomer more than before. A uniformly dispersed carbon fiber composite material is obtained, and a carbon fiber composite metal material in which carbon nanofibers are uniformly dispersed can be obtained by using this carbon fiber composite material. More specifically, rather than mixing carbon nanofibers with an elastomer having a large molecular weight as in the prior art, the liquid elastomer whose molecular weight has been reduced by the step (a) is formed in the voids of the carbon nanofibers aggregated in the step (b). The carbon nanofibers can be dispersed more uniformly in the step (c). In addition, since the elastomer free radicals produced in a large amount by molecular cleavage in the step (a) can be more firmly bonded to the surface of the carbon nanofibers in the step (b), carbon in the step (c) Nanofibers can be dispersed more uniformly than before.

In the method for producing a carbon fiber composite metal material according to the present invention,
The liquid elastomer obtained in the step (a) has a first spin-spin relaxation time (T2n) of 3000 μsec in an uncrosslinked body measured at 30 ° C. by the Hahn echo method using pulsed NMR. Beyond
The mixture of rubber-like elastic bodies obtained in step (c) has a first spin-spin relaxation time (T2n) of 3000 μsec or less as measured at 30 ° C. by the Hahn echo method using pulsed NMR. Can do.

In the method for producing a carbon fiber composite metal material according to the present invention,
The first spin-spin relaxation time (T2n) of the liquid elastomer obtained in the step (a) is equal to the first spin-spin relaxation time (T2n) of the elastomer before mastication in the step (a). ) To 5 to 30 times.

In the method for producing a carbon fiber composite metal material according to the present invention,
The first spin-spin relaxation time (T2n) of the rubber-like elastic mixture obtained in the step (c) is the first spin-spin relaxation time of the elastomer before mastication in the step (a). It can be 0.5 to 10 times (T2n).

In the method for producing a carbon fiber composite metal material according to the present invention,
The first spin-spin relaxation time (T2n) of the carbon fiber composite material obtained in the step (d) is equal to the first spin-spin relaxation of the rubber-like elastic material mixture obtained in the step (c). It can be made shorter than time (T2n).

In the method for producing a carbon fiber composite metal material according to the present invention,
The carbon fiber composite material has a first spin-spin relaxation time (T2n) of 100 to 3000 μsec in an uncrosslinked body, measured at 150 ° C. by a Hahn echo method using pulsed NMR, The component fraction (fnn) of the component having a spin-spin relaxation time (T2nn) can be less than 0.2.

In the method for producing a carbon fiber composite metal material according to the present invention,
In the step (c), the molecular weight of the elastomer can be increased by heat-treating the mixture obtained in the step (b).

In the method for producing a carbon fiber composite metal material according to the present invention,
The step (d) can be performed using an open roll method with a roll interval of 0.5 mm or less.

In the method for producing a carbon fiber composite metal material according to the present invention,
In the step (d), the roll temperature may be set to 0 to 50 ° C.

  The elastomer used in the step (a) of the present invention may be a rubber-based elastomer or a thermoplastic elastomer. Moreover, in the case of a rubber-type elastomer, in the case of a rubber-type elastomer, an uncrosslinked body is preferable because of easy mixing of carbon nanofibers.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.

  FIG. 1 is a diagram schematically showing the step (a) by the open roll method used in the present embodiment. FIG. 2 is a diagram schematically showing the step (b). FIG. 3 is a diagram schematically showing the step (d). FIG.4 and FIG.5 is a figure which shows typically the osmosis | permeation method of a process (e). FIG. 6 is an enlarged schematic view showing a part of the carbon fiber composite metal material.

In the method for producing a carbon fiber composite metal material according to the present embodiment, the first spin-spin relaxation time (T2n) in an uncrosslinked body, measured at 30 ° C. by the Hahn echo method using pulsed NMR, is 100. The step (a) of obtaining a liquid elastomer by masticating an elastomer having a viscosity of 3000 μsec to reduce the molecular weight of the elastomer, and the average diameter of the elastomer obtained in the step (a) is 0.5 to 500 nm. A step (b) of obtaining a mixture by mixing the carbon nanofibers of step (b), and a step of obtaining a mixture of rubbery elastic bodies by increasing the molecular weight of the elastomer in the mixture obtained in the step (b) (c) And the rubber-like elastic material mixture obtained in the step (c) are kneaded, and the carbon nanofibers are separated into the elastomer by a shearing force. And step (d) of obtaining the carbon fiber composite material by, after the step by heating said carbon fiber composite material obtained in (d) is decomposed and vaporized the elastomer to obtain a carbon-based material, decomposing vaporized elastomer and impregnated with the metal material in the voids of the carbonaceous material Deki by, including a step (e) to obtain a carbon fiber-metal composite material of the elastomer of the carbon fiber composite material to replace the metallic material .
In the method for producing a carbon fiber composite metal material according to the present embodiment, the first spin-spin relaxation time (T2n) in an uncrosslinked body, measured at 30 ° C. by the Hahn echo method using pulsed NMR, is 100. The step (a) of obtaining a liquid elastomer by masticating an elastomer having a viscosity of 3000 μsec to reduce the molecular weight of the elastomer, and the average diameter of the elastomer obtained in the step (a) is 0.5 to 500 nm. A step (b) of obtaining a mixture by mixing the carbon nanofibers of step (b), and a step of obtaining a mixture of rubbery elastic bodies by increasing the molecular weight of the elastomer in the mixture obtained in the step (b) (c) And the rubber-like elastic material mixture obtained in the step (c) are kneaded, and the carbon nanofibers are separated into the elastomer by a shearing force. Step (d) to obtain a carbon fiber composite material, and the carbon fiber composite material obtained in the step (d) and the particles of the metal material are mixed and then powder-molded to form the carbon fiber composite material. A step (e) of obtaining a carbon fiber composite metal material by substituting the inside elastomer with a metal material.
In the method for producing a carbon fiber composite metal material according to the present embodiment, the first spin-spin relaxation time (T2n) in an uncrosslinked body, measured at 30 ° C. by the Hahn echo method using pulsed NMR, is 100. The step (a) of obtaining a liquid elastomer by masticating an elastomer having a viscosity of 3000 μsec to reduce the molecular weight of the elastomer, and the average diameter of the elastomer obtained in the step (a) is 0.5 to 500 nm. A step (b) of obtaining a mixture by mixing the carbon nanofibers of step (b), and a step of obtaining a mixture of rubbery elastic bodies by increasing the molecular weight of the elastomer in the mixture obtained in the step (b) (c) And the rubber-like elastic material mixture obtained in the step (c) are kneaded, and the carbon nanofibers are separated into the elastomer by a shearing force. A step (d) of obtaining a carbon fiber composite material, wherein the particles of the metal material are dispersed in the elastomer during the steps (a) to (d), and in the step (d) The method further includes a step (e) of powder-molding the obtained carbon fiber composite material containing particles of the metal material and replacing the elastomer in the carbon fiber composite material with the metal material to obtain a carbon fiber composite metal material. .
In the method for producing a carbon fiber composite metal material according to the present embodiment, the first spin-spin relaxation time (T2n) in an uncrosslinked body, measured at 30 ° C. by the Hahn echo method using pulsed NMR, is 100. The step (a) of obtaining a liquid elastomer by masticating an elastomer having a viscosity of 3000 μsec to reduce the molecular weight of the elastomer, and the average diameter of the elastomer obtained in the step (a) is 0.5 to 500 nm. A step (b) of obtaining a mixture by mixing the carbon nanofibers of step (b), and a step of obtaining a mixture of rubbery elastic bodies by increasing the molecular weight of the elastomer in the mixture obtained in the step (b) (c) And the rubber-like elastic material mixture obtained in the step (c) are kneaded, and the carbon nanofibers are separated into the elastomer by a shearing force. A step (d) for obtaining a carbon fiber composite material, and a step (e) for obtaining a carbon fiber composite metal material by replacing the elastomer in the carbon fiber composite material obtained in the step (d) with a metal material. And including.
In the method for producing a carbon fiber composite metal material according to the present embodiment, the first spin-spin relaxation time (T2n) in an uncrosslinked body, measured at 30 ° C. by the Hahn echo method using pulsed NMR, is 100. The step (a) of obtaining a liquid elastomer by masticating an elastomer having a viscosity of 3000 μsec to reduce the molecular weight of the elastomer, and the average diameter of the elastomer obtained in the step (a) is 0.5 to 500 nm. A step (b) of obtaining a mixture by mixing the carbon nanofibers of step (b), and a step of obtaining a mixture of rubbery elastic bodies by increasing the molecular weight of the elastomer in the mixture obtained in the step (b) (c) And the rubber-like elastic material mixture obtained in the step (c) are kneaded, and the carbon nanofibers are separated into the elastomer by a shearing force. Step (d) to obtain a carbon fiber composite material, and the carbon fiber composite material obtained in step (d) is infiltrated with a molten metal material to form an elastomer in the carbon fiber composite material. Replacing the material to obtain a carbon fiber composite metal material (e).

(I) Step (a)
The process (a) in the manufacturing method of the carbon fiber composite metal material concerning this Embodiment is demonstrated.
In the step (a), the raw material elastomer is masticated to reduce the molecular weight of the elastomer, thereby obtaining a liquid elastomer. Since the viscosity of the elastomer decreases when the molecular weight decreases due to mastication, the elastomer easily penetrates into the voids of the carbon nanofibers aggregated in the step (b). The raw material elastomer has a first spin-spin relaxation time (T2n) of the network component of 100 to 3000 μsec in an uncrosslinked body, as measured at 30 ° C. by the Hahn echo method using pulsed NMR. The raw material elastomer is masticated to lower the molecular weight of the elastomer, and an elastomer having a first spin-spin relaxation time (T2n) exceeding 3000 μsec is obtained. In addition, the first spin-spin relaxation time (T2n) of the elastomer obtained in the step (a) is the first spin-spin relaxation time (T2n) of the raw material elastomer before mastication in the step (a). It is preferable that it is 5 to 30 times.

  The kneading in the step (a) is different from the general kneading performed while the elastomer remains in a solid state, and the molecular weight is significantly reduced by cutting the elastomer molecules by applying a strong shearing force, for example, by an open roll method. The process is carried out until the liquid state is reached until it shows a flow unsuitable for kneading. For example, when the open roll method is used, this step (a) is performed at a roll temperature of 20 ° C. (minimum mastication time 60 minutes) to 150 ° C. (minimum mastication time 10 minutes). FIG. 1 is a diagram schematically showing a step (a) by an open roll method using two rolls. The first roll 10 and the second roll 20 are arranged at a predetermined interval d, for example, 0.1 mm to 1.0 mm, and are rotated forward at rotational speeds V1 and V2 in the directions indicated by arrows in FIG. It rotates in reverse. The elastomer 30 is wound around the second roll 20 set to a predetermined temperature, and the elastomer 30 is taken out of the second roll 20 by performing the mastication in the step (a). The step (a) is not limited to the open roll method as shown in FIG. 1, and a closed kneading method or a multi-screw extrusion kneading method can also be used.

  The spin-spin relaxation time (T2) obtained by the Hahn-echo method using pulsed NMR is a measure representing the molecular mobility of a substance. Specifically, when the spin-spin relaxation time (T2) of the elastomer is measured by the Hahn-echo method using pulsed NMR, the first component having the first spin-spin relaxation time (T2n) having a short relaxation time And a second component having a second spin-spin relaxation time (T2nn) having a longer relaxation time. The first component corresponds to a polymer network component (skeleton molecule), and the second component corresponds to a polymer non-network component (branch and leaf component such as a terminal chain). The shorter the first spin-spin relaxation time (T2n), the lower the molecular mobility and the harder the elastomer. Moreover, it can be said that the longer the first spin-spin relaxation time (T2n), the higher the molecular mobility and the softer the elastomer. When the first spin-spin relaxation time (T2n) exceeds 3000 μsec, the elastomer flows and becomes liquid, and therefore has little elasticity. The state of the substance having the first spin-spin relaxation time (T2n) exceeding 3000 μs is, for example, T2n of water at room temperature (30 ° C.) is 143 msec, T2n of paraffin oil (PW180) is 15 msec, and T2n of liquid rubber Has been found to be liquid, such as 4000 μs to 10,000 μs.

  As a measurement method in the pulsed NMR method, the solid echo method, the CPMG method (Car Purcell, Mayboom, Gill method) or the 90 ° pulse method can be applied instead of the Hahn echo method. However, since the carbon fiber composite material according to the present invention has a moderate spin-spin relaxation time (T2), the Hahn echo method is most suitable. In general, the solid echo method and the 90 ° pulse method are suitable for short T2 measurement, the Hahn echo method is suitable for medium T2 measurement, and the CPMG method is suitable for long T2 measurement.

  The raw material elastomer used in the step (a) preferably has a molecular weight of 5,000 to 5,000,000, more preferably 20,000 to 3,000,000. If the molecular weight of the elastomer is greater than 5 million, the elastomer becomes too hard and the processing in step (a) becomes difficult. The elastomer obtained by the step (a) is masticated to significantly reduce the molecular weight, for example, the molecular weight becomes 100 to 20,000.

  In addition, the raw material elastomer has an unsaturated bond or group having affinity for the carbon nanofiber, particularly the radical at its terminal, in at least one of the main chain, the side chain and the terminal chain, or such It preferably has a property of easily generating radicals or groups. Such unsaturated bonds or groups include double bonds, triple bonds, carbonyl groups, carboxyl groups, hydroxyl groups, amino groups, nitrile groups, ketone groups, amide groups, epoxy groups, ester groups, vinyl groups, halogen groups, urethane groups. And at least one selected from functional groups such as a burette group, an allophanate group and a urea group.

  Carbon nanofibers usually have a six-membered ring of carbon atoms and a closed end with a five-membered ring introduced at the tip. It tends to occur, and it is easy to generate radicals and functional groups in the part. In the present embodiment, it is preferable that at least one of the main chain, side chain, and terminal chain of the elastomer has an unsaturated bond or group having high affinity (reactivity or polarity) with the radical of carbon nanofiber. By using a simple elastomer, it is possible to bond the elastomer and the carbon nanofiber. In particular, in the present embodiment, since the elastomer molecules are cleaved by the step (a) more than ordinary peptization, a large amount of free radicals are generated, and the elastomer free radicals are easily combined with the carbon nanofibers. Become.

  Elastomers include natural rubber (NR), epoxidized natural rubber (ENR), styrene-butadiene rubber (SBR), nitrile rubber (NBR), chloroprene rubber (CR), ethylene propylene rubber (EPR, EPDM), and butyl rubber (IIR). ), Chlorobutyl rubber (CIIR), acrylic rubber (ACM), silicone rubber (Q), fluorine rubber (FKM), butadiene rubber (BR), epoxidized butadiene rubber (EBR), epichlorohydrin rubber (CO, CEO), urethane rubber (U), elastomers such as polysulfide rubber (T); olefin (TPO), polyvinyl chloride (TPVC), polyester (TPEE), polyurethane (TPU), polyamide (TPEA), styrene (SBS) ), Etc., thermoplastic elastomer ; And it can be a mixture thereof. Particularly preferred are highly polar elastomers that easily generate free radicals during elastomer kneading, such as natural rubber (NR) and nitrile rubber (NBR).

(II) Step (b)
The process (b) in the manufacturing method of the carbon fiber composite metal material concerning this Embodiment is demonstrated.
In step (b), the elastomer obtained in step (a) is mixed with carbon nanofibers having an average diameter of 0.5 to 500 nm to obtain a mixture. This step (b) can be performed using the same two rolls following the step (a), for example, when the open roll method is used as in the step (a). FIG. 2 is a diagram schematically showing the step (b) by the open roll method using two rolls. The roll interval d and the roll rotation speeds V1 and V2 may remain as set in step (a). A predetermined amount of carbon nanofibers 40 is put into the elastomer 30 wound around the rotating second roll 20, and the elastomer 30 and the carbon nanofibers 40 are mixed. The step (b) is not limited to the open roll method as shown in FIG. 2, and a closed kneading method or a multi-screw extrusion kneading method can also be used. However, in the step (b), since the elastomer 30 is in a liquid state and its elasticity is remarkably reduced, the aggregated carbon nanofibers are not so dispersed even when kneaded in a state where the free radicals of the elastomer and the carbon nanofibers are combined. . Therefore, the mixture obtained in step (b) is almost the same as the first spin-spin relaxation time (T2n) of the elastomer obtained in step (a).

  The carbon nanofibers used in step (b) preferably have an average diameter of 0.5 to 500 nm, and more preferably have an average diameter of 0.5 to 100 nm. The carbon nanofibers preferably have an average length of 0.01 to 1000 μm. The compounding quantity of carbon nanofiber is not specifically limited, It can set according to a use.

  Examples of carbon nanofibers include so-called carbon nanotubes. The carbon nanotube is a single-walled carbon nanotube (single wall carbon nanotube: SWNT) in which one surface of graphite having a carbon hexagonal mesh surface is wound in one layer, and a double-walled carbon nanotube (double wall carbon nanotube: DWNT) in two layers. There are multi-walled carbon nanotubes (MWNT: multi-walled carbon nanotubes) wound in three or more layers, but the carbon nanotubes used in step (b) are composed only of a single-layer structure or only a multi-layer structure. A single layer structure and a multilayer structure may be mixed. As the multi-walled carbon nanotube (MWNT: multi-wall carbon nanotube), it is also possible to use a vapor-grown carbon fiber (VGCF: registered trademark of Showa Denko) with particularly few defects. A carbon material partially having a carbon nanotube structure can also be used. In addition to the name “carbon nanotube”, it may be called “graphite fibril nanotube”. Carbon nanofibers that have been graphitized at about 2300 ° C. to 3200 ° C. with a graphitization catalyst such as boron, boron carbide, beryllium, aluminum, and silicon may be used.

  Single-walled carbon nanotubes or multi-walled carbon nanotubes are manufactured to a desired size by an arc discharge method, a laser ablation method, a vapor phase growth method, or the like.

  The arc discharge method is a method of obtaining multi-walled carbon nanotubes deposited on a cathode by performing an arc discharge between electrode materials made of carbon rods in an argon or hydrogen atmosphere at a pressure slightly lower than atmospheric pressure. In addition, the single-walled carbon nanotube is obtained by mixing the carbon rod with a catalyst such as nickel / cobalt to cause arc discharge and adhering to the inner surface of the processing vessel.

  The laser ablation method melts and evaporates the carbon surface by irradiating a strong YAG laser pulsed laser beam onto a carbon surface mixed with a target catalyst such as nickel / cobalt in a rare gas (eg argon). This is a method for obtaining single-walled carbon nanotubes.

  The vapor phase growth method is a method in which hydrocarbons such as benzene and toluene are thermally decomposed in the gas phase to synthesize carbon nanotubes. More specifically, a fluid catalyst method, a zeolite supported catalyst method, and the like can be exemplified.

  Before the carbon nanofibers are kneaded with the elastomer in step (b), surface treatment such as ion implantation, sputter etching, plasma treatment, etc. is performed in advance to improve adhesion and wettability with the elastomer. can do.

(III) Step (c)
The step (c) in the method for producing the carbon fiber composite metal material according to the present embodiment will be described.
In step (c), the molecular weight of the elastomer in the mixture obtained in step (b) is increased to obtain a mixture of rubber-like elastic bodies. Since the mixture obtained in the step (c) is a rubber-like elastic body, the first spin-spin relaxation time (T2n) of the network component measured at 30 ° C. by the Hahn echo method using the pulse method NMR is 3000 μsec or less. The first spin-spin relaxation time (T2n) of the rubber-like elastic mixture obtained in the step (c) is the first spin-spin of the raw material elastomer before mastication in the step (a). The relaxation time (T2n) is preferably 0.5 to 10 times. The mixture of rubber-like elastic bodies obtained in the step (c) can extend the molecular chain cleaved in the step (a) again to increase the molecular weight of the elastomer, whereby the first spin-spin relaxation time. (T2n) is reduced to 3000 μsec or less, and the elasticity of the elastomer which has been lost due to the loss of elasticity is restored to form a mixture of rubber-like elastic bodies. The molecular weight of the elastomer in the rubber-like elastic mixture obtained in the step (c) is preferably 5000 to 150,000. The elasticity of the rubber-like elastic mixture can be expressed by the molecular form of the elastomer (observable by molecular weight) and the molecular mobility (observable by T2n).

  In the step (c), the molecular weight of the elastomer can be increased by heat-treating the mixture obtained in the step (b). This heat treatment is preferably performed for 10 to 100 hours by placing the mixture in a heating furnace set at a predetermined temperature, for example, 40 ° C. to 100 ° C. By such a heat treatment, the molecular chain is extended due to, for example, bonding between elastomer free radicals present in the mixture obtained in the step (b), and the molecular weight is increased. When step (c) is carried out in a short time, a small amount of a crosslinking agent is mixed in step (b), for example, 1/2 or less of an appropriate amount of the crosslinking agent, and the mixture is heated in step (c). The molecular weight can be increased in a short time by a treatment (for example, an annealing treatment) and a crosslinking reaction. When the molecular weight of the elastomer is increased by a crosslinking reaction, it is preferable to set the blending amount of the crosslinking agent, the heating time, and the heating temperature to such an extent that kneading is not difficult in step (d).

(IV) Step (d)
The step (d) in the method for producing the carbon fiber composite metal material according to the present embodiment will be described.
In the step (d), the rubber-like elastic mixture obtained in the step (c) is kneaded, and the carbon nanofibers are dispersed in the elastomer by a shearing force to obtain a carbon fiber composite material. The mixture of rubber-like elastic bodies obtained in the step (c) has a first spin-spin relaxation time (T2n / 30 ° C.) of 3000 μsec or less, and the elastomer has a molecular weight of 5000 to 150,000. The carbon nanofibers can be uniformly dispersed in the elastomer by applying a shearing force to such a mixture. The first spin-spin relaxation time (T2n) of the carbon fiber composite material obtained in the step (d) is a rubber-like shape obtained in the step (c) by uniformly dispersing the carbon nanofibers. It can be shorter than the first spin-spin relaxation time (T2n) of the elastic mixture.

  FIG. 3 is a diagram schematically showing the step (c) by the open roll method using two rolls. The first roll 10 and the second roll 20 are arranged at a predetermined interval d, for example, 1.5 mm. First, in a state where the first and second rolls 10 and 20 are rotated, the rubber elastic mixture 50 obtained in the step (c) is wound around the second roll 20. The rubber-like elastic mixture 50 is taken out from the open roll, and the roll interval d is preferably set to 0.5 mm or less, more preferably 0.1 to 0.5 mm, and the mixture is put into the open roll. Then do thinning multiple times. The number of thinning is preferably about 5 to 10 times, for example. When the surface speed of the first roll 10 is V1, and the surface speed of the second roll 20 is V2, the ratio of the surface speeds (V1 / V2) in thinness is 1.05 to 3.00. It is preferably 1.05 to 1.2. By using such a surface velocity ratio, a desired shear force can be obtained. The thinned carbon fiber composite material is rolled with a roll and dispensed into a sheet.

  In this step (d), in order to obtain as high a shearing force as possible, the mixture 50 is kneaded by setting the roll temperature to a relatively low temperature of preferably 0 to 50 ° C., more preferably 5 to 30 ° C. It is preferable that the measured temperature of the mixture 50 is adjusted to 0 to 50 ° C. Due to the shearing force thus obtained, a high shearing force acts on the mixture 50, and the aggregated carbon nanofibers are separated from each other so as to be pulled out one by one to the elastomer molecules, and dispersed in the elastomer. . In particular, in the mixture 50, the elastomer penetrates into the voids of the carbon nanofiber aggregates by the steps (a) and (b), and the elastomer and the carbon nanofibers are combined, and the molecular weight of the elastomer is increased by the step (c). By restoring the elasticity together with the viscosity, it has elasticity, viscosity, and chemical interaction with the carbon nanofibers, and the carbon nanofibers can be easily dispersed. And the carbon fiber composite material excellent in the dispersibility and dispersion stability of carbon nanofiber (it is hard to re-aggregate carbon nanofiber) can be obtained.

  More specifically, when the elastomer and the carbon nanofibers are mixed in the step (b), the liquid elastomer having a reduced viscosity enters the carbon nanofibers, and a specific portion of the elastomer is chemically interlinked. It binds to the highly active part of the carbon nanofiber by action. In particular, by mixing the carbon nanofibers with the elastomer in a liquid state, the elastomer molecules can easily enter the carbon nanofiber aggregates compared to the case where the carbon nanofibers are mixed with the elastomer of the conventional rubbery elastic body. Become. However, even if kneaded as it is, the force for dispersing the aggregated carbon nanofibers cannot be applied to the elastomer, and therefore the carbon nanofibers cannot be uniformly dispersed in the elastomer. Therefore, next, in step (c), the molecular length of the elastomer is extended to an appropriate length to restore the molecular mobility of the elastomer (recovering elasticity), and in step (d), a strong shear is applied to the rubber-like elastic mixture. When the force acts, the carbon nanofibers move with the movement of the elastomer, and the aggregated carbon nanofibers are separated and dispersed in the elastomer by the restoring force of the elastomer due to elasticity after shearing. Become. According to this Embodiment, when a mixture is extruded from between narrow rolls, a mixture deform | transforms thicker than a roll space | interval with the restoring force by the elasticity of an elastomer. It can be inferred that the deformation causes the mixture subjected to a strong shear force to flow more complicatedly and disperse the carbon nanofibers in the elastomer. The carbon nanofibers once dispersed are prevented from reaggregating due to chemical interaction with the elastomer, and can have good dispersion stability.

  The step of dispersing the carbon nanofibers in the elastomer by a shearing force is not limited to the open roll method, and a closed kneading method or a multiaxial extrusion kneading method can also be used. In short, in this step, it is sufficient that a shearing force capable of separating the aggregated carbon nanofibers can be given to the elastomer. In particular, the open roll method is preferably used in the step (d) because it can measure and manage not only the roll temperature but also the actual temperature of the mixture.

  The method for producing a carbon fiber composite metal material may further include a step of crosslinking the carbon fiber composite material obtained in step (d). Further, the carbon fiber composite material may be molded without being crosslinked. The carbon fiber composite material may remain in the form of a sheet obtained by the open roll method, or a rubber molding process generally employed by the carbon fiber composite material obtained in the step (d), for example, injection molding method, transfer molding. A complicated shape may be formed by a method, a press molding method, or the like, or a continuous shape product such as a sheet shape, a square bar shape, or a round bar shape may be formed by an extrusion molding method, a calendar processing method, or the like.

  In the method for producing a carbon fiber composite metal material according to the present embodiment, a compounding agent usually used in processing of an elastomer such as rubber can be added. A well-known thing can be used as a compounding agent. Examples of the compounding agent include a crosslinking agent, a vulcanizing agent, a vulcanization accelerator, a vulcanization retarder, a softening agent, a plasticizer, a curing agent, a reinforcing agent, a filler, an antiaging agent, and a coloring agent. it can. These compounding agents can be added to the elastomer in step (b), for example.

(V) Carbon fiber composite material The carbon fiber composite material concerning this Embodiment is demonstrated.
In the carbon fiber composite material obtained by the step (d) of the carbon fiber composite metal material production method, carbon nanofibers are uniformly dispersed in an elastomer as a matrix. This can be said to be a state where the elastomer is restrained by the carbon nanofibers. In this state, the mobility of the elastomer molecules constrained by the carbon nanofibers is smaller than that when not constrained by the carbon nanofibers. Therefore, the first spin-spin relaxation time (T2n), the second spin-spin relaxation time (T2nn), and the spin-lattice relaxation time (T1) of the carbon fiber composite material according to the present embodiment are the carbon nanofibers. It becomes shorter than the case of an elastomer alone which does not contain, and in particular, it becomes shorter when the carbon nanofibers are uniformly dispersed. In addition, the spin-lattice relaxation time (T1) in the crosslinked body changes in proportion to the mixing amount of the carbon nanofibers.

  In addition, in the state where the elastomer molecules are constrained by the carbon nanofibers, it is considered that the non-network component (non-network chain component) decreases for the following reason. In other words, when the molecular mobility of the elastomer decreases as a whole due to carbon nanofibers, the non-network component becomes more difficult to move, making it easier to behave like the network component, and the non-network component ( It is considered that the non-network component is reduced due to the fact that the terminal chain is easy to move and is easily adsorbed to the active site of the carbon nanofiber. Therefore, the component fraction (fnn) of the component having the second spin-spin relaxation time (T2nn) is smaller than that of the elastomer alone not including the carbon nanofiber. Since the component fraction (fn) of the component having the first spin-spin relaxation time (T2n) is fn + fnn = 1, the component fraction (fn) is larger than that of the elastomer alone not including the carbon nanofibers.

  From the above, it is desirable that the carbon fiber composite material according to the present embodiment has a measured value obtained by the Hahn echo method using the pulse method NMR in the following range.

  That is, the carbon fiber composite material has a first spin-spin relaxation time (T2n) of 100 to 3000 μsec in an uncrosslinked body, measured at 150 ° C. by the Hahn echo method using pulsed NMR, The component fraction (fnn) of the component having the spin-spin relaxation time (T2nn) is preferably less than 0.2.

  The spin-lattice relaxation time (T1) measured by the inversion recovery method using pulsed NMR is a measure representing the molecular mobility of a substance together with the spin-spin relaxation time (T2). Specifically, the shorter the spin-lattice relaxation time of the elastomer, the lower the molecular mobility and the harder the elastomer, and the longer the spin-lattice relaxation time, the higher the molecular mobility and the softer the elastomer.

  In the carbon fiber composite material according to the present embodiment, the flow temperature in the temperature dependence measurement of dynamic viscoelasticity is preferably 20 ° C. or more higher than the flow temperature of the raw material elastomer alone. In the carbon fiber composite material of the present embodiment, carbon nanofibers are well dispersed in the elastomer. This can be said to be a state where the elastomer is restrained by the carbon nanofibers as described above. In this state, the elastomer has a smaller molecular motion than the case where it does not contain carbon nanofibers, resulting in a decrease in fluidity. By having such a flow temperature characteristic, the carbon fiber composite material of the present embodiment has a low temperature dependency of dynamic viscoelasticity, and as a result, has excellent heat resistance.

  As the carbon fiber composite material of the present embodiment, natural rubber, synthetic rubber or thermoplastic elastomer can be used as an elastomer material as it is, or as a raw material for composite materials such as metals and resins, that is, as a supply source of carbon nanofibers. It can be used as a so-called master batch. Carbon nanofibers usually have the property of being entangled with each other and difficult to disperse in a medium. However, when the carbon fiber composite material of the present embodiment is used as a raw material for a metal or resin composite material, the carbon nanofibers are already dispersed in the elastomer, so this raw material and a medium such as a metal or resin are used. By mixing, the carbon nanofibers can be easily dispersed in the medium.

(VI) Step (e)
The step (e) in the method for producing the carbon fiber composite metal material according to the present embodiment will be described.
In the step (e), the carbon fiber composite metal material is obtained by replacing the elastomer in the carbon fiber composite material obtained in the step (d) with a metal material. In the step (e), the carbon fiber composite material obtained by heating the carbon fiber composite material obtained in the step (d) to decompose and vaporize an elastomer to obtain a carbon material, and then decompose and vaporize the elastomer. The metal material can be infiltrated into the gap. Specifically, for example, the following method can be adopted as the replacing step.
(1) The step (e) according to the present embodiment is a method in which the carbon fiber composite material obtained in the step (d) and the metal material particles are mixed and then powder-molded.
(2) In the step (e) according to the present embodiment, the carbon fiber composite material including particles of the metal material obtained in the step (d) can be powder-molded.
(3) The step (e) according to the present embodiment is a method in which the carbon fiber composite material obtained in the step (d) and the metal material in a fluid state are mixed and then solidified.
(4) The step (e) according to the present embodiment is a method in which a molten metal material is infiltrated into the carbon fiber composite material obtained in the step (d).

(Powder molding method)
First, the step (e) using the powder molding method (1) will be described. In this step (e), for example, the carbon fiber composite material obtained in step (d) and the metal material particles are mixed and then compressed in a mold, and the sintering temperature of the metal material particles (metal material) When the particles are aluminum, the carbon fiber composite metal material can be obtained by firing at about 550 ° C.). For mixing the carbon fiber composite material and the metal material particles, an open roll method, a closed kneading method, a multi-screw extrusion kneading method, or the like in step (d) can be employed. In this step (e), it is preferable that the temperature raising step up to the sintering temperature is performed slowly, and by raising the temperature, the elastomer contained in the carbon fiber composite material is first decomposed and vaporized to form a carbon-based material. Next, a reducing agent such as magnesium mixed with the particles of the metal material is vaporized to make the inside of the mold a reducing atmosphere. Further, by raising the temperature, the metal material particles serving as a matrix are melted and fired. At this time, it is preferable that nitrogen gas is introduced into the mold from an inert gas such as a nitrogen gas cylinder to make the mold or the sintering atmosphere an inert atmosphere.

  The powder molding according to the present embodiment is the same as the powder molding in the metal molding process, and includes so-called powder metallurgy. In addition to a general sintering method, a discharge plasma sintering method using a plasma sintering apparatus ( SPS), powder injection molding, powder extrusion molding, hot isostatic pressing (HIP), spray forming, warm molding, mechanical alloying and the like can be employed.

  In addition to the case where the carbon fiber composite material and the metal material particles are directly sintered in the mold as described above, the carbon fiber composite material is heat-treated in advance to decompose the elastomer contained in the carbon fiber composite material. After vaporizing to obtain a carbon-based material and mixing the carbon-based material and the metal material particles, the carbon-based material mixed with the metal material particles may be powder-molded. Also, dry blending, wet blending, or the like can be employed for mixing the carbon-based material, the metal material particles as a matrix, and the reducing agent. For example, in the case of wet mixing, it is desirable to mix the particulate metal of the matrix with the carbonaceous material powder in the solvent (wet mixing).

  Next, the step (e) using the powder molding method (2) will be described. In the powder molding method (1), powder molding was performed after mixing the carbon fiber composite material obtained in step (d) and the metal material particles. In the powder molding method (2), The particles of the metal material are dispersed in the elastomer during the steps (a) to (d). Therefore, since the carbon fiber composite material obtained in the step (d) contains the metal material particles in advance, the step (e) powder-forms the carbon fiber composite material containing the metal material particles as it is. be able to. For example, the metal material particles may be charged and dispersed in the elastomer kneaded with an open roll or the like in step (a), or the metal material particles may be charged in the rubber-like elastic mixture in step (d). The metal material particles and the elastomer may be mixed at any timing in the steps (a) to (d). Further, the carbon fiber composite material obtained in the step (d) may be further mixed with a desired amount of metal material particles and then powder-molded. As a method of dispersing the particles of the metal material in the elastomer, for example, a known kneading method in which an additive is mixed with the elastomer can be employed. As the powder molding method, the method described in detail in (1) above can be adopted.

(Casting method)
Next, the step (e) of casting in the mold (3) will be described. In this step (e), the carbon fiber composite material obtained in step (d) is mixed into a fluid metal material (hereinafter referred to as a molten metal), and the elastomer contained in the carbon fiber composite material is decomposed and vaporized. In addition, the carbon fiber composite metal material can be obtained by casting in a mold having a desired shape. In such a casting process, first, the carbon fiber composite material and the molten metal are mixed. A metal material such as aluminum is melted (650 to 800 ° C.) in the crucible, and the carbon fiber composite material is put into the crucible while stirring the molten aluminum melt and mixed. At this time, the stirring may be one-way rotation, but the mixing effect is enhanced by stirring in three directions (three dimensions). The molten aluminum mixed in an inert atmosphere such as a nitrogen gas atmosphere can be cast by a die casting method, a die casting method, or a low pressure casting method in which a molten metal is poured into a steel mold, for example. In addition, other high-pressure casting methods (squeeze casting), which are classified into special casting methods, such as high-pressure casting (squeeze casting), stirring the molten metal, centrifugal casting method in which the molten metal is cast into the mold by centrifugal force, etc. are adopted. be able to. In these casting methods, a carbon fiber composite material is mixed in a molten metal and solidified in a mold to form a carbon fiber composite metal material having a desired shape.

  For example, in thixocasting, after melting a metal material such as aluminum at 700 to 800 ° C., the temperature is lowered while stirring to obtain a thixotropic state at 400 to 600 ° C., and the carbon fiber composite material is mixed in that state. It is preferable. In the thixotropy state, the viscosity increases, so that uniform dispersion is possible. In these casting processes, oxidation of the molten metal (for example, molten aluminum) is prevented when performed in an inert atmosphere such as a nitrogen atmosphere, a weakly reduced atmosphere obtained by adding a small amount of hydrogen gas to nitrogen, or under reduced pressure. This is desirable because it improves the wettability with carbon nanofibers. In this casting process, the elastomer in the carbon fiber composite material is decomposed and removed by the heat of the molten metal.

  Here, it has been explained that the process of decomposing and removing the elastomer from the carbon fiber composite material is continuously performed in the casting process. However, the elastomer is decomposed and vaporized from the carbon fiber composite material in advance to mainly contain the carbon nanofibers. After obtaining the carbon-based material, it may be integrated with the molten metal using a separate infiltration method or the like.

(Penetration method)
Finally, the step (e) of allowing the metal material (4) to penetrate into the carbon fiber composite material will be described with reference to FIGS. In the step (e) of infiltrating the metal material into the carbon fiber composite material, it is preferable to use a non-pressurized permeation method. However, the permeation method is not limited to this, and for example, pressurization is performed by an atmospheric pressure such as inert gas. A pressure infiltration method can also be used. Here, an embodiment using a non-pressure infiltration method will be described. 4 and 5 schematically show the step (e) and are schematic configuration diagrams of an apparatus for producing a carbon fiber composite metal material by a non-pressure permeation method.

  Prior to the step (e), the carbon fiber composite material 4 shown in FIG. 4 is mixed with the particulate metals 41 and 42 by a known kneader such as an open roll. By mixing the carbon fiber composite material 4 with the particulate metals 41 and 42, it is easy to maintain the shape even when the elastomer is vaporized in the step (e), and the molten metal material is placed in the gaps between the particulate metals 42. It has the advantage of easy penetration. The particulate metals 41 and 42 have, for example, an average particle diameter of 500 μm or less, preferably 1 to 300 μm, and are not limited to a spherical particle shape, and may be a flat plate shape or a flake shape. The particulate metal 41 is a substance that becomes a reducing agent in the step (e), and is preferably a metal or metalloid having a melting point lower than that of the carbon nanofibers, and more preferably a low melting point (melting point of 1000 ° C. or less) High vapor pressure) metals or metalloids are preferred. The particulate metal 41 is preferably magnesium as a matrix metal reducing agent. The particulate metal 42 preferably contains the same metal as the metal material that becomes the matrix of the carbon fiber composite metal material. The particulate metal 42 is preferably a metal having a melting point lower than that of the carbon nanofibers and a metal having a melting point higher than that of the particulate metal 41. If the melting point of the particulate metal 41 satisfies the above conditions, the particulate metal 41 can be vaporized without damaging the carbon nanofibers by the heat treatment in the step (e) described later. When the particulate metal 42 is made of the same material as the matrix metal, it can be appropriately selected from iron, aluminum, magnesium, copper, zinc, etc. alone or in combination depending on the application. The particulate metal 42 is preferably aluminum which is lightweight and has good workability. Here, the metal includes a so-called alloy, for example, magnesium includes a magnesium alloy, and aluminum includes an aluminum alloy.

  As shown in FIG. 4, the carbon fiber composite material 4 may be a carbon fiber composite material 4 that has been pre-compressed in a molding die having the shape of the final product, for example. In FIG. 4, a carbon fiber composite material 4 molded in advance is placed in a sealed container 1. A lump of metal material, for example, an aluminum lump 5 serving as a matrix is disposed above the carbon fiber composite material 4. Moreover, you may deaerate the inside of the container 1 with the decompression means 2 connected to the container 1, for example, a vacuum pump. Further, nitrogen gas is introduced into the container 1 from the injection means 3 connected to the container 1. As the injection means, for example, a nitrogen gas cylinder can be used, and the introduced nitrogen gas contains a small amount of oxygen.

  Next, the carbon fiber composite material 4 and the aluminum lump 5 arranged in the container 1 are gradually heated to a melting point of aluminum or higher by a heating means (not shown) built in the container 1 and heated. First, among the materials constituting the heated carbon fiber composite material 4, the elastomer having the lowest melting point is decomposed and vaporized to obtain a carbon-based material. When the temperature inside the container 1 is further increased, particulate metal 41 (for example, magnesium particles having a melting point lower than that of aluminum) contained in the carbon fiber composite material 4 is vaporized. Further, the aluminum mass 5 having a melting point lower than that of the particulate metal 42 is heated to become a molten aluminum, and penetrates into a void formed by decomposition and vaporization of the elastomer. The particulate metal 41 can be vaporized to make the inside of the container 1 into a reducing atmosphere, and the molten aluminum easily penetrates between the particulate metals 42 by capillary action. And the heating by the heating means of the container 1 is stopped, the molten aluminum is cooled and solidified, and the carbon fiber composite metal material 6 in which the carbon nanofibers are uniformly dispersed as shown in FIG. 5 can be manufactured.

  Moreover, although the particulate metal 41 may be mixed with the carbon fiber composite material 4 as in the present embodiment, the same metal lump as the particulate metal 41 is disposed in the container 1 of this step (e). May be. In order to facilitate the penetration of the molten metal by capillary action in this step (e), the particulate metal 42 is preliminarily made into an elastomer or carbon fiber composite material during the steps (a) to (d) as described above. Although it is preferable to mix, it is not necessary to mix. Therefore, this step (e) can be carried out without mixing the particulate metals 41 and 42 with the carbon fiber composite material prior to the step (e).

  Moreover, in order to obtain the molten metal in this step (e), the lump of the metal material is disposed on the carbon fiber composite material. However, in this step (e), the molten metal may penetrate into the carbon fiber composite material, for example, The carbon fiber composite material may be immersed in the molten metal, or the molten metal may be dropped. Further, the step of decomposing and vaporizing the elastomer and the step of infiltrating the metal may be continued as described above. After the elastomer is vaporized, the carbon-based material is once taken out, for example, the carbon-based material is compressed to form pores. After measuring the size, the metal material may be infiltrated in a separate process.

  Further, the metal material described in the step (e) includes a metal alloy as described above, for example, iron and its alloy, aluminum and its alloy, magnesium and its alloy, copper and its alloy, zinc and its alloy, titanium, and the like. And an alloy thereof or the like can be appropriately selected alone or in combination according to the application. Furthermore, the carbon fiber composite metal material obtained by these production methods can be molded into a desired form by using, for example, an ingot by a casting method, a powder forging method, a powder extrusion molding method, or a powder injection molding method. .

(VII) Carbon fiber composite metal material The carbon fiber composite metal material according to the present embodiment is obtained by the above-described method for producing a carbon fiber composite metal material. FIG. 6 is an enlarged schematic view showing a part of the carbon fiber composite metal material 6 according to the present embodiment. In the carbon fiber composite metal material 6, carbon nanofibers 40 are dispersed in the metal material of the matrix 60. An amorphous peripheral phase 70 is formed around the carbon nanofiber 40. The peripheral phase 70 includes, for example, nitrogen and a small amount of oxygen, which are atmospheric gases in the step (e). When the metal of the matrix 60 is aluminum, aluminum, nitrogen, and oxygen are added so as to cover the periphery of the carbon nanofibers 40. The amorphous peripheral phase 70 is formed. In particular, the peripheral phase 70 is mainly composed of aluminum, which is the same as the metal material of the matrix, and has good wettability with the crystalline aluminum of the matrix. The ratio of the peripheral phase 70 in the carbon fiber composite metal material 6 can be easily increased or decreased depending on the content of the carbon nanofiber 40, and can also be adjusted by the heat treatment time in the permeation method of the step (e). The generation ratio of aluminum, nitrogen, and oxygen (Al / N / O) in the peripheral phase 70 is about 10/9/1. However, the oxygen concentration in the nitrogen atmosphere and the flow rate of supplied nitrogen in the step (e) Can be adjusted. The composition of the peripheral phase 70 in the carbon fiber composite metal material 6 can be observed with a field emission scanning electron microscope (FE-SEM) and examined by elemental analysis in the vicinity of the irradiation point. The peripheral phase 70 can include a crystalline phase made of, for example, aluminum nitride. For example, when the carbon fiber composite metal material obtained in the step (e) is further heat-treated at a high temperature, the peripheral phase of amorphous aluminum, nitrogen, and oxygen (Al / N / O) is crystallized. Part or all may be aluminum nitride.

  The surface of the carbon nanofibers 40 in the carbon fiber composite metal material 6 is covered with a compound layer (for example, an oxide layer) of carbon atoms and oxygen constituting the carbon nanofibers 40, and further comprises oxygen and particulate metal 41. It has a structure covered with a reactant layer with an element such as magnesium. The carbon nanofiber 40 and the peripheral phase 70 have good wettability due to these oxide layers. Such a surface structure of the carbon nanofiber can be analyzed also by X-ray spectroscopic analysis (XPS) or EDS analysis (Energy Dispersive Spectrum).

  In the carbon fiber composite metal material 6, the carbon nanofibers 40 are uniformly dispersed in the matrix 60 of the metal material, and the peripheral phases 70 covering the carbon nanofibers 40 are connected to each other to form countless fine cells. is doing. Since the carbon fiber composite metal material 6 according to the present embodiment disperses the carbon nanofibers 40 more uniformly, even if the filling amount of the carbon nanofibers 40 is small, the cells of the peripheral phase 70 are uniformly formed throughout. Is done. Therefore, for example, even when a carbon fiber composite metal material having the same compression strength as that of the conventional one is obtained, the filling amount of the carbon nanofibers 40 may be small, and expensive carbon nanofibers can be used efficiently.

  Examples of the present invention will be described below, but the present invention is not limited thereto.

(1) Sample production steps (a) of Examples 1 to 6: A 6-inch open roll (roll temperature 20 ° C., roll interval 0.5 mm) and a predetermined amount of elastomer shown in Table 1 (100 parts by weight (phr)) ) Was wound around the roll and masticated for 30 minutes, and the liquid elastomer was taken out from the open roll.
Step (b): The elastomer obtained in step (a) is again wound on an open roll (roll temperature 20 ° C., roll interval 1.0 mm), and the amount shown in Table 1 with respect to the elastomer (parts by weight (phr)) ) (Referred to as “MWNT” in Table 1), and the elastomer and carbon nanofibers were mixed to take out the mixture.
Step (c): The mixture obtained in step (b) is placed in a heat treatment furnace heated to 100 ° C. and heated for 10 hours to increase the molecular weight of the elastomer in the mixture, thereby mixing the rubber-like elastic body. Got.
Step (d): Carbon rubber obtained by repeatedly inserting the mixture of rubber-like elastic bodies obtained in Step (c) into an open roll (roll temperature 10 to 20 ° C., roll interval 0.3 mm) and repeating thinning five times. A composite material was obtained. At this time, the surface speed ratio of the two rolls was set to 1.1. The carbon fiber composite material obtained by setting the roll interval to 1.1 mm and passing through was inserted, rolled, and dispensed. The separated sheet was compression-molded at 90 ° C. for 5 minutes to obtain an uncrosslinked carbon fiber composite material sample of Examples 1 to 6 having a thickness of 1 mm and not containing aluminum particles.
Further, the carbon fiber composite material obtained through thinning is again put into an open roll, and further, pure aluminum particles having an average particle diameter of 30 μm (99.7% is aluminum) as the particulate metal are shown in Table 1 (in amounts). Part by weight (phr)) was added and mixed, and the carbon fiber composite material mixed with pure aluminum particles was rolled into a sheet and dispensed. The separated sheet was compression molded at 90 ° C. for 5 minutes to obtain an uncrosslinked carbon fiber composite material sample containing pure aluminum particles of Examples 1 to 6 having a thickness of 1 mm.
Step (e):
(Penetration method) A carbon fiber composite material containing the sheet-like pure aluminum particles was heat-treated, and a carbon fiber composite metal material was obtained by a non-pressure permeation method. More specifically, the carbon fiber composite material containing the pure aluminum particles obtained in (d) above is placed in a container (furnace), and the temperature is equal to or higher than the decomposition vaporization temperature of the elastomer in a furnace in an inert gas (nitrogen) atmosphere ( Heat treatment at 500 ° C. for 2 hours to decompose and vaporize the elastomer to obtain a carbon-based material. Further, an aluminum lump (pure aluminum ingot) as a matrix material is placed on the carbon-based material, and the temperature is higher than the melting point of aluminum. (800 ° C). The aluminum lump melted to form a molten aluminum, and the molten metal penetrated to fill the pores of the carbon-based material. After impregnating the molten aluminum, this was naturally allowed to cool and solidify to obtain carbon fiber composite metal materials of Examples 1 to 4. Table 1 shows “penetration method” in the column of the method for producing the carbon fiber composite metal material.
(Powder Extrusion Method) The carbon fiber composite material containing the sheet-like pure aluminum particles was heat-treated (500 ° C.) under a nitrogen atmosphere, the elastomer was removed, and a composite powder composed of pure aluminum particles and a carbon-based material was prepared. . This composite powder is filled (canned) into a pure aluminum can body having an outer diameter of 90 mm and an inner diameter of 80 mm, heated to 450 ° C. in an argon gas atmosphere, and the carbon fiber composite metal material of Example 5 is obtained by powder extrusion molding. Obtained. Table 1 shows “powder extrusion method” in the column of the method for producing the carbon fiber composite metal material.
(Hot isostatic pressing method) This carbon fiber composite material containing pure aluminum particles in sheet form is heat-treated (500 ° C.) in a nitrogen atmosphere to remove the elastomer, and a composite consisting of pure aluminum particles and a carbon-based material. A powder was made. The composite powder was filled into a can made of pure aluminum having an outer diameter of 90 mm and an inner diameter of 80 mm (canning), and hot isostatic (HIP) molding was performed at 500 ° C. and 500 atm in an argon gas atmosphere. A carbon fiber composite metal material was obtained. Table 1 shows “HIP molding method” in the column of the method for producing the carbon fiber composite metal material.

(2) Preparation of Sample of Comparative Example 1 A predetermined amount of elastomer (100 parts by weight (phr)) shown in Table 1 was put into a 6-inch open roll (roll temperature: 10 to 20 ° C., roll interval: 1.5 mm). , Wound around a roll, masticated for 5 minutes, charged pure aluminum particles having an average particle size of 30 μm (99.7% is aluminum) in the amount shown in Table 1 (parts by weight (phr)), and mixed. Carbon nanofibers were charged and the mixture was removed from the open roll. And the roll space | interval was narrowed from 1.5 mm to 0.3 mm, the mixture was again thrown into the open roll, and thinning was repeated 5 times to obtain a carbon fiber composite material. At this time, the surface speed ratio of the two rolls was set to 1.1. Furthermore, the carbon fiber composite material obtained by setting the roll gap to 1.1 mm and passing through was put, rolled into a sheet, and dispensed. The dispensed sheet was compression molded at 90 ° C. for 5 minutes to obtain an uncrosslinked carbon fiber composite material sample of Comparative Example 1 containing no aluminum particles having a thickness of 1 mm.
Further, the carbon fiber composite material obtained through thinning is again put into an open roll, and further, pure aluminum particles having an average particle diameter of 30 μm (99.7% is aluminum) as the particulate metal are shown in Table 1 (in amounts). Part by weight (phr)) was added and mixed, and the carbon fiber composite material mixed with pure aluminum particles was rolled into a sheet and dispensed. The dispensed sheet was compression molded at 90 ° C. for 5 minutes to obtain an uncrosslinked carbon fiber composite material sample containing pure aluminum particles of Comparative Example 1 having a thickness of 1 mm.
The carbon fiber composite material containing the sheet-like pure aluminum particles was heat-treated in the same manner as in Step (e) of Examples 1 to 4, and the carbon fiber composite metal material of Comparative Example 1 was obtained by the non-pressure permeation method. .

  In Table 1, “NR” is natural rubber, “EPDM” is ethylene propylene rubber, and “MWNT” is multi-wall carbon nanotubes manufactured by ILJIN having an average diameter of about 13 nm. In addition, the carbon fiber composite materials of Examples 1 to 6 and Comparative Example 1 are not crosslinked with a crosslinking agent.

(3) Measurement Examples 1 to 6 using pulse method NMR In raw material elastomer, elastomer when wound around a roll before mastication in step (a), elastomer after mastication, step (b) The mixture obtained in step 1, the mixture obtained in step (c) and the carbon fiber composite material sample obtained in step (d) were measured by the Hahn echo method using pulsed NMR. In Comparative Example 1, the raw material elastomer, the elastomer when wound on a roll, the mixture containing carbon nanofibers, and the carbon fiber composite material sample after thinning were subjected to the Hahn echo method using pulsed NMR. Measurement was carried out. The carbon fiber composite material sample in the step (d) is an uncrosslinked carbon fiber composite material sample containing no pure aluminum particles and an uncrosslinked carbon fiber composite material sample containing pure aluminum particles. It was measured.
This measurement was performed using “JMN-MU25” manufactured by JEOL Ltd. The measurement was performed under the conditions of the observation nucleus of ¹ H, the resonance frequency of 25 MHz, and the 90 ° pulse width of 2 μsec. The Pi was changed in various ways using the pulse sequence of the Hahn-echo method (90 ° x-Pi-180 ° x). The decay curve was measured. Further, the sample was measured by inserting it into a sample tube up to an appropriate range of the magnetic field. The measurement temperatures were 30 ° C. and 150 ° C., and the measurement temperatures were entered in parentheses in Tables 1 and 2. By this measurement, the component fraction (fnn) of the component having the first spin-spin relaxation time (T2n) and the second spin-spin relaxation time (T2nn) was determined for each sample. The measurement results are shown in Table 1.

(4) Measurement of specific gravity Specific gravity of the carbon fiber composite metal material samples of Examples 1 to 6 and Comparative Example 1 was determined.

(5) Measurement of compression strength About the carbon fiber composite metal material sample of Examples 1-6 and Comparative Example 1, the maximum value, the minimum value, and the average value of compression strength (MPa) were measured. The measurement of the compressive yield strength was 0.2% yield strength (σ0.2) when a 10 × 10 × 5 (thickness) mm sample was compressed at 0.01 mm / min. The results are shown in Table 1.

  From Table 1, according to Examples 1 to 6 of the present invention, the following was confirmed. That is, the carbon fiber composite metal material samples of Examples 1 to 6 of the present invention were denser than the carbon fiber composite metal material sample of Comparative Example 1 and were dense and less defective than 2.65. . Moreover, the maximum value, the minimum value, and the average value of the carbon fiber composite metal material samples of Examples 1 to 6 of the present invention are the same or larger than those of the carbon fiber composite metal material sample of Comparative Example 1. From the results, it was found that the carbon fiber composite metal materials of Examples 1 to 6 were homogeneous throughout with reduced variations in mechanical properties. In particular, the maximum value of the compression strength of Example 1 is the same as the value of Comparative Example 1, and even if the compounding amount of the carbon nanofiber is ¼ of the conventional, the same compression strength is obtained by using the present invention. It was found that the economy was improved.

  In Examples 1 to 6 and Comparative Example 1, in order to clarify the effect of improving the dispersibility of the carbon nanofiber according to the present invention, a carbon fiber composite metal material sample obtained by non-pressure infiltration was used. However, in actual use, hot isostatic pressing (HIP) or the like can be used to further reduce the variation in mechanical properties.

It is a figure which shows a process (a) typically. It is a figure which shows a process (b) typically. It is a figure which shows a process (d) typically. It is a figure which shows typically the osmosis | permeation method of a process (e). It is a figure which shows typically the osmosis | permeation method of a process (e). It is a schematic diagram which expands and shows a part of carbon fiber composite metal material.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Container 2 Depressurization means 3 Injection | pouring means 4 Carbon fiber composite material 5 Aluminum lump 6 Carbon fiber composite metal material 10 1st roll 20 2nd roll 30 Elastomer 40 Carbon nanofiber 41 Particulate metal 42 Particulate metal 50 Mixture 60 Matrix 70 Peripheral phase d Roll interval V1 Surface speed V1 of first roll V2 Surface speed of second roll

Claims (13)

The molecular weight of the elastomer is reduced by masticating an elastomer having a first spin-spin relaxation time (T2n) of 100 to 3000 μsec in an uncrosslinked product, measured at 30 ° C. by the Hahn echo method using pulsed NMR. And (a) obtaining a liquid elastomer,
Mixing the elastomer obtained in the step (a) with carbon nanofibers having an average diameter of 0.5 to 500 nm to obtain a mixture (b);
Increasing the molecular weight of the elastomer in the mixture obtained in step (b) to obtain a rubbery elastic mixture (c);
Kneading the mixture of rubber-like elastic bodies obtained in the step (c), and dispersing the carbon nanofibers in the elastomer by a shearing force to obtain a carbon fiber composite material; and
The carbon fiber composite material obtained in the step (d) is heated to decompose and vaporize an elastomer to obtain a carbon-based material, and then the metal material is inserted into voids of the carbon-based material formed by decomposing and vaporizing the elastomer. was allowed to permeate, the step (e) of the elastomer of the carbon fiber composite material to replace the metallic material to obtain a carbon fiber-metal composite material,
A method for producing a carbon fiber composite metal material, comprising: The molecular weight of the elastomer is reduced by masticating an elastomer having a first spin-spin relaxation time (T2n) of 100 to 3000 μsec in an uncrosslinked product, measured at 30 ° C. by the Hahn echo method using pulsed NMR. And (a) obtaining a liquid elastomer,
Mixing the elastomer obtained in the step (a) with carbon nanofibers having an average diameter of 0.5 to 500 nm to obtain a mixture (b);
Increasing the molecular weight of the elastomer in the mixture obtained in step (b) to obtain a rubbery elastic mixture (c);
Kneading the mixture of rubber-like elastic bodies obtained in the step (c), and dispersing the carbon nanofibers in the elastomer by a shearing force to obtain a carbon fiber composite material; and
After mixing the particles of step (d) obtained in the carbon fiber composite material and the metal material, and powder forming the carbon fiber composite elastomer of the carbon fiber composite material to replace the metallic material Obtaining a metal material (e);
A method for producing a carbon fiber composite metal material, comprising: The molecular weight of the elastomer is reduced by masticating an elastomer having a first spin-spin relaxation time (T2n) of 100 to 3000 μsec in an uncrosslinked product, measured at 30 ° C. by the Hahn echo method using pulsed NMR. And (a) obtaining a liquid elastomer,
Mixing the elastomer obtained in the step (a) with carbon nanofibers having an average diameter of 0.5 to 500 nm to obtain a mixture (b);
Increasing the molecular weight of the elastomer in the mixture obtained in step (b) to obtain a rubbery elastic mixture (c);
Kneading the mixture of rubber-like elastic bodies obtained in the step (c), and dispersing the carbon nanofibers in the elastomer by a shearing force to obtain a carbon fiber composite material; and
Including
During the steps (a) to (d), particles of the metal material are dispersed in an elastomer,
Said carbon fiber composite material powder molding comprising particles of the metal material obtained in the step (d), to obtain a carbon fiber-metal composite material of the elastomer of the carbon fiber composite material to replace the metallic material A method for producing a carbon fiber composite metal material, further comprising a step (e). The molecular weight of the elastomer is reduced by masticating an elastomer having a first spin-spin relaxation time (T2n) of 100 to 3000 μsec in an uncrosslinked product, measured at 30 ° C. by the Hahn echo method using pulsed NMR. And (a) obtaining a liquid elastomer,
Mixing the elastomer obtained in the step (a) with carbon nanofibers having an average diameter of 0.5 to 500 nm to obtain a mixture (b);
Increasing the molecular weight of the elastomer in the mixture obtained in step (b) to obtain a rubbery elastic mixture (c);
Kneading the mixture of rubber-like elastic bodies obtained in the step (c), and dispersing the carbon nanofibers in the elastomer by a shearing force to obtain a carbon fiber composite material; and
Replacing the elastomer in the carbon fiber composite material obtained in the step (d) with a metal material to obtain a carbon fiber composite metal material (e);
Only including,
The method (e) is a method for producing a carbon fiber composite metal material, wherein the carbon fiber composite material obtained in the step (d) and the metal material in a fluid state are mixed and then solidified . The molecular weight of the elastomer is reduced by masticating an elastomer having a first spin-spin relaxation time (T2n) of 100 to 3000 μsec in an uncrosslinked product, measured at 30 ° C. by the Hahn echo method using pulsed NMR. And (a) obtaining a liquid elastomer,
Mixing the elastomer obtained in the step (a) with carbon nanofibers having an average diameter of 0.5 to 500 nm to obtain a mixture (b);
Increasing the molecular weight of the elastomer in the mixture obtained in step (b) to obtain a rubbery elastic mixture (c);
Kneading the mixture of rubber-like elastic bodies obtained in the step (c), and dispersing the carbon nanofibers in the elastomer by a shearing force to obtain a carbon fiber composite material; and
The carbon fiber composite material obtained in the step (d), said infiltrated molten metallic material, to obtain an elastomer carbon fiber-metal composite material is replaced with the metallic material of the carbon fiber composite material (E) and
A method for producing a carbon fiber composite metal material, comprising: In any of claims 1 to 5 ,
The liquid elastomer obtained in the step (a) has a first spin-spin relaxation time (T2n) of 3000 μsec in an uncrosslinked body measured at 30 ° C. by the Hahn echo method using pulsed NMR. Beyond
The mixture of rubber-like elastic bodies obtained in the step (c) has a first spin-spin relaxation time (T2n) of 3000 μsec or less as measured at 30 ° C. by the Hahn echo method using pulsed NMR. A method for producing a carbon fiber composite metal material. In any one of Claims 1 thru | or 6 .
The first spin-spin relaxation time (T2n) of the liquid elastomer obtained in the step (a) is equal to the first spin-spin relaxation time (T2n) of the elastomer before mastication in the step (a). ) 5 to 30 times the production method of the carbon fiber composite metal material. In any one of Claims 1 thru | or 7 ,
The first spin-spin relaxation time (T2n) of the rubber-like elastic mixture obtained in the step (c) is the first spin-spin relaxation time of the elastomer before mastication in the step (a). The manufacturing method of a carbon fiber composite metal material which is 0.5 to 10 times (T2n). In any of claims 1 to 8 ,
The first spin-spin relaxation time (T2n) of the carbon fiber composite material obtained in the step (d) is equal to the first spin-spin relaxation of the rubber-like elastic material mixture obtained in the step (c). The manufacturing method of a carbon fiber composite metal material shorter than time (T2n). In any one of Claim 1 thru | or 9 ,
The carbon fiber composite material has a first spin-spin relaxation time (T2n) of 100 to 3000 μsec in an uncrosslinked body, measured at 150 ° C. by a Hahn echo method using pulsed NMR, A method for producing a carbon fiber composite metal material, wherein a component fraction (fnn) of a component having a spin-spin relaxation time (T2nn) is less than 0.2. In any one of Claims 1 thru | or 10 ,
In the step (c), the mixture obtained in the step (b) is heat-treated to increase the molecular weight of the elastomer. In any one of Claims 1 thru | or 11 ,
The said process (d) is a manufacturing method of a carbon fiber composite metal material performed using the open roll method whose roll space | interval is 0.5 mm or less. In any of claims 1 to 12 ,
The step (d) is a method for producing a carbon fiber composite metal material, wherein the roll temperature is set to 0 to 50 ° C.