JP4177243B2 - Method for producing carbon fiber composite metal material - Google Patents

Description

The present invention relates to a method of producing a carbon fiber-metal composite materials.

  In recent years, composite materials using carbon nanofibers have attracted attention. Such a composite material is expected to improve mechanical strength and the like by including carbon nanofibers.

  Also, as a method of casting a composite metal material, magnesium vapor is permeated and dispersed in a porous molded body made of oxide ceramics, and at the same time, nitrogen gas is introduced so that the molten metal is permeated into the porous molded body. A casting method has been proposed (see, for example, Patent Document 1).

  However, since the carbon nanofibers have strong cohesiveness with each other, it is very difficult to uniformly disperse the carbon nanofibers on the base material of the composite metal material. Therefore, at present, it is difficult to obtain a composite metal material of carbon nanofibers having desired characteristics, and expensive carbon nanofibers cannot be efficiently used.

In addition, the conventional method for casting a composite metal material in which a molten metal is infiltrated into a porous molded body made of an oxide ceramic is a complicated process, so that industrial production is difficult.
JP-A-10-183269

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

The method for producing a carbon fiber composite metal material according to the present invention includes:
A step (a) of mixing the carbon nanofibers in an elastomer and dispersing them by a shearing force to obtain a carbon fiber composite material;
A step (b) of infiltrating a molten metal into the carbon fiber composite material and replacing the elastomer with the metal;
A step (c) of solidifying the molten metal of the step (b) after the step (b);
including.

  In the production method of the present invention, the carbon nanofibers are separated from each other without being entangled by infiltrating the molten metal into the carbon fiber composite material in which the carbon nanofibers are already uniformly dispersed and replacing the elastomer with the metal. And a uniformly dispersed carbon fiber composite metal material can be obtained.

Moreover, the carbon fiber composite metal material obtained by the production method of the present invention is excellent in mechanical strength such as rigidity, particularly rigidity at high temperature, by containing carbon nanofibers in a good dispersion state. Furthermore, since the carbon fiber composite metal material of the present invention has high mechanical strength, the molded product can be thinned, and the size and weight can be reduced.

  In the present invention, the metal may be aluminum or an aluminum alloy.

  The elastomer may be a rubber elastomer or a thermoplastic elastomer. In the case of a rubber-based elastomer, the elastomer may be either a crosslinked body or an uncrosslinked body. As the raw material elastomer, an uncrosslinked product is used in the case of a rubber-based elastomer.

  In 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 second spin-spin relaxation time (T2nn) does not exist or is 1000 to 10000 μsec, and the component fraction (fnn) of the component having the second spin-spin relaxation time is less than 0.2. be able to.

  In the present invention, the carbon fiber composite material has a first spin-spin relaxation time (T2n) of 100 to 2000 μsec in a crosslinked body, measured at 150 ° C. by a Hahn echo method using pulsed NMR. Yes, the second spin-spin relaxation time (T2nn) does not exist or is 1000 to 5000 μs, and the component fraction (fnn) of the component having the second spin-spin relaxation time is less than 0.2 Can be.

  The carbon fiber composite material has such characteristics, and carbon nanofibers are uniformly dispersed in an elastomer as a base material. Therefore, the carbon fiber composite metal material obtained by replacing the elastomer of the carbon fiber composite material with a metal has carbon nanofibers uniformly dispersed in the metal as the base material.

Wherein the step of elastomer dispersed by shear force of the carbon nanofibers can b Lumpur interval performed using the following open-roll method of 0.5 mm.

In the present invention, the step (b) includes a step of disposing a metal mass above the carbon fiber composite material;
Heating and melting the metal mass to form the molten metal, vaporizing the elastomer in the carbon fiber composite material, and infiltrating the molten metal to replace the elastomer;
Can have. Such a method for producing a carbon fiber composite metal material can obtain a carbon fiber composite metal material in which an elastomer of a carbon fiber composite material in which carbon nanofibers are uniformly dispersed is substituted with a metal as described above. Further, it is preferable to use the carbon fiber composite material in the step (b) as it is uncrosslinked since the elastomer can be easily decomposed and the penetration of the molten metal is quick.

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

The method for producing a carbon fiber composite metal material according to the present embodiment includes a step (a) of obtaining a carbon fiber composite material by mixing the carbon nanofibers in an elastomer and dispersing the carbon nanofibers by a shearing force.
A step (b) of infiltrating a molten metal into the carbon fiber composite material and replacing the elastomer with the metal;
A step (c) of solidifying the molten metal of the step (b) after the step (b);
including.

  In addition, the step (a) of obtaining the carbon fiber composite material according to the present invention further includes a step of forming into a desired shape while being crosslinked or uncrosslinked, and the step in a state of being formed into a desired shape. It may be used for (b).

  In the method for producing a carbon fiber composite metal material according to the present invention, the step (b) includes a step of disposing a metal lump above the carbon fiber composite material, and heating and melting the metal lump to melt the metal. And evaporating the elastomer in the carbon fiber composite material and replacing the molten metal with the molten metal.

  For example, the elastomer has characteristics such as having an unsaturated bond or group having an affinity for carbon nanofibers, having a certain length of molecular length, and having flexibility. Is desirable. Moreover, it is desirable that the step of dispersing the carbon nanofibers in the elastomer with a shearing force is kneaded with a shearing force as high as possible.

  (A) First, the elastomer will be described.

  The elastomer preferably has a molecular weight of 5,000 to 5,000,000, more preferably 20,000 to 3,000,000. When the molecular weight of the elastomer is within this range, the elastomer molecules are entangled with each other and are connected to each other. Therefore, the elastomer easily invades the aggregated carbon nanofibers, and thus has a great effect of separating the carbon nanofibers. If the molecular weight of the elastomer is less than 5000, the elastomer molecules cannot be sufficiently entangled with each other, and the effect of dispersing the carbon nanofibers is reduced even when a shearing force is applied in a later step. If the molecular weight of the elastomer is greater than 5 million, the elastomer becomes too hard and processing becomes difficult.

  The elastomer preferably has a network component spin-spin relaxation time (T2n / 30 ° C.) of 100 to 3000 μsec, more preferably 200, measured at 30 ° C. by the Hahn echo method using pulsed NMR. Or 1000 μs. By having a spin-spin relaxation time (T2n / 30 ° C.) in the above range, the elastomer can be flexible and have sufficiently high molecular mobility. Accordingly, when the elastomer and the carbon nanofiber are mixed, the elastomer can easily enter the gap between the carbon nanofibers due to high molecular motion. If the spin-spin relaxation time (T2n / 30 ° C.) is shorter than 100 μsec, the elastomer cannot have sufficient molecular mobility. Also, if the spin-spin relaxation time (T2n / 30 ° C.) is longer than 3000 μsec, the elastomer tends to flow like a liquid, and it becomes difficult to disperse the carbon nanofibers.

  The elastomer preferably has a spin-spin relaxation time (T2n) of the network component of 100 to 2000 μsec in the crosslinked product, measured at 30 ° C. by the Hahn echo method using pulsed NMR. The reason is the same as that of the uncrosslinked product described above. That is, when an uncrosslinked product having the above conditions is crosslinked by the production method of the present invention, T2n of the obtained crosslinked product is approximately within the above range.

  The spin-spin relaxation time 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 of the elastomer is measured by the Hahn-echo method using pulsed NMR, a first component having a first spin-spin relaxation time (T2n) having a short relaxation time, and relaxation A second component having a longer spin-spin relaxation time (T2nn) is detected. 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, the lower the molecular mobility and the harder the elastomer. Further, it can be said that the longer the first spin-spin relaxation time, the higher the molecular mobility and the softer the elastomer.

  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 elastomer has an unsaturated bond or group having an affinity for carbon nanofibers, particularly a radical at its terminal, in at least one of the main chain, side chain and terminal chain, or such a radical or group has Easy to generate. Such an unsaturated bond or group can be at least one selected from a double bond, a triple bond and a functional group. Examples of functional groups include carbonyl group, carboxyl group, hydroxyl group, amino group, nitrile group, ketone group, amide group, epoxy group, ester group, vinyl group, halogen group, urethane group, burette group, allophanate group, and urea. There are groups .

  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, 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 the carbon nanofiber, so that the elastomer and carbon Nanofibers can be combined. This makes it possible to easily disperse the carbon nanofibers by overcoming the cohesive force.

  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.

  (B) Next, the carbon nanofiber will be described.

  The carbon nanofibers preferably have an average diameter of 0.5 to 500 nm, and more preferably 0.5 to 30 nm in order to improve the strength of the carbon fiber composite material. 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. The carbon fiber composite material of the present embodiment uses a crosslinked elastomer, an uncrosslinked elastomer, or a thermoplastic polymer as a raw material for a metal composite material. When the carbon fiber composite material of the present embodiment is used as a raw material for a metal composite material, carbon nanofibers can be included at a ratio of 0.01 to 50% by weight. The raw material of the metal composite material can be used as a so-called master batch as a supply source of carbon nanofibers when carbon nanofibers are mixed with metal.

  Examples of carbon nanofibers include so-called carbon nanotubes. Carbon nanotubes have a single-layer structure in which graphene sheets with carbon hexagonal mesh surfaces are closed in a cylindrical shape, or a multilayer structure in which these cylindrical structures are arranged in a nested manner. That is, the carbon nanotube may be composed of only a single-layer structure or a multilayer structure, and the single-layer structure and the multilayer structure may be mixed. 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”.

  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.

  The carbon nanofibers can be improved in adhesion and wettability with the elastomer by performing surface treatment such as ion implantation treatment, sputter etching treatment, and plasma treatment in advance before being kneaded with the elastomer.

  (C) Next, the step (a) in which carbon nanofibers are mixed in an elastomer and dispersed by a shearing force will be described.

  In the present embodiment, an example using an open roll method in which a roll interval is 0.5 mm or less will be described as the step (a) of mixing carbon nanofibers with an elastomer.

  FIG. 1 is a diagram schematically showing an open roll method using two rolls. In FIG. 1, the code | symbol 10 shows a 1st roll and the code | symbol 20 shows a 2nd roll. The first roll 10 and the second roll 20 are arranged at a predetermined interval d, preferably 1.0 mm or less, more preferably 0.1 to 0.5 mm. The first and second rolls rotate in the normal direction or the reverse direction. In the illustrated example, the first roll 10 and the second roll 20 rotate in the direction indicated by the arrow. When the surface speed of the first roll 10 is V1, and the surface speed of the second roll 20 is V2, the surface speed ratio (V1 / V2) is preferably 1.05 to 3.00. By using such a predetermined surface velocity ratio, a desired shear force can be obtained. First, when the elastomer 30 is wound around the second roll 20 while the first and second rolls 10 and 20 are rotated, a so-called bank 32 in which the elastomer is accumulated between the rolls 10 and 20 is formed. The carbon nanofiber 40 is added into the bank 32 and the first and second rolls 10 and 20 are rotated. Further, the distance between the first and second rolls 10 and 20 is reduced to the distance d described above, and the first and second rolls 10 and 20 are rotated at the predetermined surface speed ratio in this state. Thereby, a high shearing force acts on the elastomer 30, and the carbon nanofibers aggregated by the shearing force are separated from each other so as to be pulled out one by one and dispersed in the elastomer 30.

  In this step (a), in order to obtain as high a shearing force as possible, the elastomer and the carbon nanofiber are mixed at a relatively low temperature of preferably 0 to 50 ° C., more preferably 5 to 30 ° C. . When the open roll method is used, it is desirable to set the temperature of the roll to the above temperature.

  At this time, the elastomer of the present embodiment has the characteristics described above, that is, the molecular morphology (molecular length) of the elastomer, the molecular motion, the chemical interaction with the carbon nanofiber, and the like. Therefore, a carbon fiber composite material excellent in dispersibility and dispersion stability (hardness of re-aggregation of carbon nanofibers) can be obtained. More specifically, when an elastomer and carbon nanofibers are mixed, an elastomer having a reasonably long molecular length and high molecular mobility penetrates into 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 this state, if a strong shearing force acts on the mixture of the elastomer and carbon nanofibers, the carbon nanofibers move as the elastomer moves, and the aggregated carbon nanofibers are separated and dispersed in the elastomer. Will be. The carbon nanofibers once dispersed are prevented from reaggregating due to chemical interaction with the elastomer, and can have good dispersion stability.

The step (a) of dispersing the carbon nanofibers in the elastomer by a shearing force is not limited to the open roll method. 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.

  The carbon fiber composite material obtained by dispersing the carbon nanofibers in the elastomer described above and mixing them together (mixing / dispersing step) is molded by crosslinking with a crosslinking agent or molded without crosslinking. be able to. As a molding method at this time, for example, a carbon fiber composite material can be obtained by performing a compression molding process, an extrusion molding process, or the like. In the compression molding process, for example, a carbon fiber composite material in which carbon nanofibers are dispersed is molded in a pressed state for a predetermined time (for example, 20 minutes) in a molding die having a desired shape set at a predetermined temperature (for example, 175 ° C.). The method further includes the step of:

  In the step of mixing / dispersing the elastomer and the carbon nanofiber, or subsequently, a compounding agent usually used in processing of the 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.

  (D) Next, the carbon fiber composite material obtained by the above method will be described.

  In the carbon fiber composite material of the present embodiment, carbon nanofibers are uniformly dispersed in an elastomer as a base material. 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 the elastomer simple substance which does not contain. 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 is smaller than that in the case of an elastomer alone that does not include 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, in the uncrosslinked carbon fiber composite material, the first spin-spin relaxation time (T2n) measured at 150 ° C. is 100 to 3000 μsec, and the second spin-spin relaxation time (T2nn) exists. Or the component fraction (fnn) of the component having the second spin-spin relaxation time is preferably less than 0.2.

  In the crosslinked carbon fiber composite material, the first spin-spin relaxation time (T2n) measured at 150 ° C. is 100 to 2000 μs, and the second spin-spin relaxation time (T2nn) does not exist. Alternatively, it is preferably 1000 to 5000 μsec, and the component fraction (fnn) of the component having the second spin-spin relaxation time is preferably less than 0.2.

  Moreover, as for the carbon fiber composite material concerning this Embodiment, it is desirable that the measured value obtained by the Hahn echo method using pulse method NMR exists in the following ranges. That is, it is preferable that the amount of change in the spin-lattice relaxation time (T1) (ΔT1) measured at 150 ° C. of the crosslinked carbon fiber composite material per 1 volume% of the carbon nanofibers is 1 msec or more lower than that of the elastomer alone. More preferably, it is preferably 2 to 15 msec.

  The spin-lattice relaxation time (T1) measured by the Hahn-echo 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 described above, the carbon fiber composite material of the present embodiment is used as a raw material for composite materials such as metals. 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 composite material, the carbon nanofibers are already dispersed in the elastomer, so that by mixing this raw material and a medium such as a metal, Carbon nanofibers can be easily dispersed in a medium.

  (E) Next, the step (b) of infiltrating the molten metal into the carbon fiber composite material and the step (c) of solidifying the molten metal will be described.

  In the present embodiment, as the step (b), the metal mass is disposed above the carbon fiber composite material, the metal mass is heated and melted to obtain the molten metal, and in the carbon fiber composite material The step of casting using a so-called non-pressure permeation method, including the step of vaporizing the elastomer and permeating the molten metal to replace the elastomer, will be described in detail with reference to FIGS. To do.

  FIG.2 and FIG.3 is a schematic block diagram of the apparatus which manufactures a carbon fiber composite metal material by the non-pressurization osmosis | permeation method. As the carbon fiber composite material obtained in the above embodiment, for example, the carbon fiber composite material 4 compression-molded in a molding die having the shape of the final product can be used. The carbon fiber composite material 4 is preferably not cross-linked. This is because the penetration rate of the molten metal is increased because it is not crosslinked. In FIG. 2, a carbon fiber composite material 4 (for example, carbon nanofibers 40 are mixed in an uncrosslinked elastomer 30) is placed in a sealed container 1. A metal lump such as an aluminum lump 5 is arranged above the carbon fiber composite material 4. Next, the carbon fiber composite material 4 and the aluminum lump 5 arranged in the container 1 are heated to the melting point of aluminum or higher by a heating means (not shown) built in the container 1. The heated aluminum lump 5 is melted to form a molten aluminum (metal melt). In addition, the elastomer 30 in the carbon fiber composite material 4 in contact with the molten aluminum is decomposed and vaporized, and the molten aluminum (metal melt) penetrates into the void formed by the decomposition of the elastomer 30.

  In the carbon fiber composite material 4 according to the present embodiment, the void formed by the decomposition of the elastomer 30 can permeate the entire molten aluminum earlier by capillary action. And as a process (c), the heating by the heating means of the container 1 was stopped, the molten metal which permeated the mixed material 4 was cooled and solidified, and the carbon nanofibers 40 as shown in FIG. 3 were uniformly dispersed. The carbon fiber composite metal material 6 can be manufactured.

  Further, before the container 1 is heated, the inside of the container 1 may be degassed by the decompression means 2 connected to the container 1, for example, a vacuum pump. Furthermore, nitrogen gas may be introduced into the container 1 from an inert gas injection means 3 connected to the container 1, for example, a nitrogen gas cylinder.

  In the present embodiment, a reducing atmosphere can be generated up to the inside by decomposing the elastomer contained in the carbon fiber composite material, so that there is no pressureless permeation method without preparing a reducing atmosphere treatment chamber as in the prior art. Can be cast by. This is because when the molten aluminum is infiltrated, the molecular tip of the thermally decomposed elastomer becomes a radical, and it is considered that the oxide (alumina) on the surface of the aluminum block 5 is reduced by the radical. Furthermore, the surface of the carbon nanofiber is activated by the radicals of the decomposed elastomer molecules, and the wettability with the molten aluminum is improved. The carbon fiber composite metal material thus obtained has carbon nanofibers uniformly dispersed in an aluminum matrix. In addition, by performing this casting process in an inert atmosphere, oxidation of molten aluminum is prevented, and wettability with carbon nanofibers is further improved.

  In the present embodiment, the metal melt permeation step (b) by the non-pressure permeation method has been described. However, the present invention is not limited to this, and the so-called additive that permeates the carbon fiber composite material while pressurizing the metal melt. It is also possible to use a pressure osmosis method.

  In addition, when the carbon fiber composite material is molded in a mold having a desired form by a compression molding process, an extrusion molding process, or the like, as described in the above (C), the process (b) By performing steps (c) and (c), a carbon fiber composite metal material having a desired form can be obtained. Therefore, by using a carbon fiber composite material molded in a desired form in advance, a carbon fiber composite metal material having a desired form, for example, a final product form, can be obtained without preparing a casting mold.

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

(1) Preparation of carbon fiber composite material samples (Experimental Examples 1-6, Comparative Experimental Examples 1-3)
First, the sample of the carbon fiber composite material used for an Example was obtained. Specifically, a sample was obtained by kneading a predetermined amount of carbon nanofibers with the polymer material shown in Table 1 by the open roll method. As the sample, an uncrosslinked sample and a crosslinked sample were prepared by the following method.

(A) Preparation of uncrosslinked sample 1) A 6-inch open roll (roll temperature: 10 to 20 ° C.) was charged with a predetermined amount (100 g) of a polymer substance (100 parts by weight (phr)) shown in Table 1, It was wound around a roll.

  2) Carbon nanofibers (described as “CNT” in Table 1) in an amount (parts by weight) shown in Table 1 with respect to the polymer material were added to the polymer material. At this time, the roll gap was set to 1.5 mm.

  3) When the carbon nanofibers were added, the mixture of the polymer substance and the carbon nanofibers was taken out from the roll.

  4) The roll gap was narrowed from 1.5 mm to 0.3 mm, and the mixture was introduced to make it thin. At this time, the surface speed ratio of the two rolls was set to 1.1. Thinning was repeated 10 times.

  5) The roll was set to a predetermined gap (1.1 mm), and the thinned mixture was charged and dispensed.

  In this way, uncrosslinked samples (carbon fiber composite materials) of Experimental Examples 1 to 6 and Comparative Experimental Examples 2 and 3 were obtained.

  An elastomer such as EPDM was used as the polymer material in Experimental Examples 1 to 6. As the polymer plasticizer of Comparative Experimental Example 1, liquid 2-diethylhexyl phthalate (molecular weight: 391) was used. As Comparative Experimental Example 2, ethyl cellulose which is a thermoplastic resin was used. Further, as Comparative Experimental Example 3, an uncrosslinked sample of an elastomer (EPDM) containing no carbon nanofibers was obtained in the same manner except that the carbon nanofibers were not mixed in the above steps 1) to 5).

(B) Production of crosslinked sample 1) to 4) were performed in the same manner as the uncrosslinked sample.

  5) A roll was set at a predetermined gap (1.1 mm), a thinned mixture was charged, and a predetermined amount of a crosslinking agent (2 parts by weight) was further charged. The mixture was then dispensed.

6) A sample cut into a mold size was set in a mold and subjected to press crosslinking at 175 ° C. and 100 kgf / cm ² for 20 minutes.

  In this way, crosslinked samples (carbon fiber composite materials) of Experimental Examples 1 to 5 and Comparative Experimental Example 3 were obtained. In Experimental Example 6, SBS (styrene-butadiene-styrene thermoplastic elastomer) is used as the raw material elastomer, and no crosslinking is performed. In Comparative Experimental Example 1, a liquid polymer plasticizer is used, and crosslinking is not performed. In Comparative Experimental Example 2, a thermoplastic resin is used, and no crosslinking is performed.

(C) Preparation of carbon fiber composite metal material The uncrosslinked sample (carbon fiber composite material) obtained in the above-mentioned (a) Examples 1 to 5 was placed in a container (furnace), and an aluminum lump (ingot) was used. It was placed on it and heated to the melting point of aluminum in an inert gas (nitrogen) atmosphere. The aluminum mass melted into a molten aluminum, and the molten metal penetrated to replace the elastomer of the uncrosslinked sample. After impregnating the molten aluminum, it was naturally cooled and solidified to obtain a carbon fiber composite metal material.

(2) Measurement Using Pulse Method NMR Each uncrosslinked sample and crosslinked sample were measured by the Hahn echo method using pulse method NMR. 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 temperature was 150 ° C. By this measurement, the first spin-spin relaxation time (T2nn), the second spin-spin relaxation time (T2nn), and the second spin-spin relaxation of the raw material elastomer alone, the uncrosslinked sample of the composite material, and the crosslinked sample The component fraction (fnn) of the component having time was determined. In addition, about the raw material elastomer simple substance, it calculated | required also about the 1st spin-spin relaxation time (T2n) of the raw material elastomer simple substance in case measurement temperature is 30 degreeC. For the crosslinked sample of the carbon fiber composite material, the spin-lattice relaxation time variation (ΔT1) converted per 1% by volume of the carbon nanofiber was determined. The measurement results are shown in Table 1.

(3) Measurement of E ′ (dynamic viscoelastic modulus), TB (tensile strength) and EB (cut elongation) E ′, TB and EB were measured according to JIS K 6521-1993 for the crosslinked sample of the carbon fiber composite material. . These results are shown in Table 1.

(4) Measurement of flow temperature About the raw material elastomer simple substance and the crosslinked sample of carbon fiber composite material, the flow temperature was measured by dynamic viscoelasticity measurement (JIS K 6394). Specifically, the flow temperature was determined by applying a sine vibration (± 0.1% or less) to a sample having a width of 5 mm, a length of 40 mm, and a thickness of 1 mm, and measuring the stress and phase difference δ generated thereby. At this time, the temperature was changed from −70 ° C. to 150 ° C. at a rate of temperature increase of 2 ° C./min. The results are shown in Table 1. In Table 1, the case where no sample flow phenomenon was observed up to 150 ° C. was described as “150 ° C. or higher”.

  From Table 1, according to Experimental Examples 1 to 6 of the present invention, the following was confirmed. That is, the spin-spin relaxation time (T2n and T2nn / 150 ° C.) at 150 ° C. in the composite materials containing carbon nanofibers (uncrosslinked sample and crosslinked sample) is compared with that of the raw material elastomer alone not containing carbon nanofibers. Short. In addition, the component fraction (fnn / 150 ° C.) in the composite material containing carbon nanofibers (uncrosslinked sample and crosslinked sample) is smaller than that of an elastomer alone not containing carbon nanofibers. Furthermore, the spin-lattice relaxation time (T1) in the crosslinked sample containing carbon nanofibers is lower by a change amount (ΔT1) than in the case of the raw material elastomer not containing carbon nanofibers. From these, it can be seen that the carbon nanofibers are well dispersed in the carbon fiber composite material according to the experimental example.

  This can be clearly understood by comparing Experimental Examples 1 and 2 with Comparative Experimental Example 3. That is, in Comparative Experimental Example 3 that does not include carbon nanofibers, the spin-spin relaxation time (T2n and T2nn / 150 ° C.) of the uncrosslinked sample is not much different from that of the raw material elastomer alone. On the other hand, in Experimental Examples 1 and 2 of the present invention, the spin-spin relaxation time (T2n and T2nn / 150 ° C.) of the uncrosslinked sample is considerably shorter than that of the raw material elastomer alone. And in Experimental example 2 with a large carbon nanofiber content, the spin-spin relaxation time (T2nn / 150 ° C.) of the uncrosslinked sample was not detected. Thus, it was confirmed that in the uncrosslinked sample, Experimental Examples 1 and 2 were significantly different from Comparative Experimental Example 3 in terms of T2n and T2nn. The same was confirmed for the component fraction (fnn / 150 ° C.).

  For the crosslinked sample, it was confirmed that the spin-spin relaxation time (T2n and T2nn / 150 ° C.) was shorter than that of the raw material elastomer alone. In particular, in Experimental Example 2 in which the content of carbon nanofibers was large, the spin-spin relaxation time (T2nn / 150 ° C.) of the crosslinked sample was not detected. From this, it was confirmed that in the crosslinked sample, Experimental Examples 1 and 2 were significantly different from Comparative Experimental Example 3 in terms of T2n and T2nn. The same was confirmed for the component fraction (fnn / 150 ° C.). Further, the amount of change in spin-lattice relaxation time (ΔT1) converted per 1% by volume of carbon nanofibers showed a large value, and it was confirmed that the molecular mobility was lower than that of the raw material elastomer alone. It was.

  Also, from the results of E ′, TB and EB using the crosslinked sample, by including carbon nanofibers, the dynamic storage elastic modulus and tensile strength are improved while maintaining the cut elongation according to the experimental example of the present invention. In addition, it was confirmed that the carbon nanofibers can provide a significant reinforcing effect. This can be clearly understood by comparing Experimental Examples 1 and 2 with Comparative Experimental Example 3 that does not include carbon nanofibers. In particular, in Experimental Example 2 where the proportion of carbon nanofibers is large, it can be seen that the dynamic storage elastic modulus and tensile strength are remarkably improved.

  Furthermore, since the flow temperature in the composite material containing carbon nanofibers (uncrosslinked sample) is 20 ° C. or higher compared to the case of an elastomer alone not containing carbon nanofibers, the temperature dependence of dynamic viscoelasticity is small, It turns out that it has the outstanding heat resistance.

  In Comparative Experimental Example 1, the carbon nanofibers could not be dispersed because the molecular weight of the elastomer was too small. In Comparative Experimental Example 1, the spin-spin relaxation time and the characteristics E ′, TB, and EB could not be measured.

  In Comparative Experimental Example 2, since the first spin-spin relaxation time (T2n) at 30 ° C. of the raw material elastomer was too small, it was confirmed that the carbon nanofibers could not be sufficiently dispersed. Also, since the spin-spin relaxation time (T2nn) at 150 ° C. is too large, the molecular mobility is too high to apply a shearing force to the sample, and it is also difficult to disperse the carbon nanofibers. Was confirmed.

  In Comparative Experimental Example 3, since no carbon nanofiber was included, no reinforcing effect was observed.

  Moreover, as a result of observing the carbon fiber composite metal material (aluminum is a matrix) of Examples 1 to 6 with a microscope, in the observation of the metal forming state with a metal microscope, almost no voids are observed, which is good in an electron microscope (SEM). In the observation of the dispersion state of the carbon nanofibers, almost no aggregation of the carbon nanofibers was observed, which was good. In Comparative Examples 1 and 2, the carbon nanofibers are not included and the casting is not performed.

  From the above, according to the present invention, it has become clear that carbon nanofibers that are generally difficult to disperse into the substrate are uniformly dispersed in the elastomer. In particular, from the observation result of the microscope, it was found that the wettability between the carbon nanofiber and the aluminum in the carbon fiber composite metal material of the present invention was good.

It is a figure which shows typically the kneading | mixing method of the elastomer and carbon nanofiber by the open roll method used in this Embodiment. It is a schematic block diagram of the apparatus which manufactures a carbon fiber composite metal material by the non-pressure penetrating method. It is a schematic block diagram of the apparatus which manufactures a carbon fiber composite metal material by the non-pressure penetrating method.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Container 2 Pressure reduction means 3 Injection means 4 Carbon fiber composite material 5 Aluminum lump 6 Carbon fiber composite metal material 10 First roll 20 Second roll 30 Elastomer 40 Carbon nanofiber

Claims (14)

A step (a) in which carbon nanofibers are mixed in an elastomer and dispersed by shearing force to obtain a carbon fiber composite material;
A step (b) of infiltrating a molten metal into the carbon fiber composite material and replacing the elastomer with the metal;
A step (c) of solidifying the molten metal of the step (b) after the step (b);
A method for producing a carbon fiber composite metal material, comprising: In claim 1,
The method for producing a carbon fiber composite metal material, wherein the metal is aluminum or an aluminum alloy. In claim 1 or 2 ,
The method for producing a carbon fiber composite metal material, wherein the elastomer has a molecular weight of 5,000 to 5,000,000. In any of claims 1 to 3 ,
The elastomer backbone, at least one side chain and terminal chain, the double bond, triple bond, at least one has a method of the carbon fiber-metal composite material is selected from the government functional groups. In any of claims 1 to 4 ,
The elastomer is a carbon fiber composite metal material having a network component spin-spin relaxation time (T2n) of 100 to 3000 μsec in an uncrosslinked body, measured at 30 ° C. by a Hahn echo method using pulsed NMR. Production method. In any of claims 1 to 5 ,
Production of a carbon fiber composite metal material wherein the elastomer has a spin-spin relaxation time (T2n) of a network component of 100 to 2000 μsec in a crosslinked product, measured at 30 ° C. by a Hahn echo method using pulse NMR. Method. In any one of Claims 1 thru | or 6 .
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 spin-spin relaxation time (T2nn) does not exist or is 1000 to 10,000 μsec, and the component fraction (fnn) of the component having the second spin-spin relaxation time is less than 0.2. A method for producing a metal material. In any one of claims 1 to 7,
The carbon fiber composite material has a first spin-spin relaxation time (T2n) of 100 to 2000 μsec in the crosslinked body measured at 150 ° C. by a Hahn echo method using pulsed NMR, and a second spin A carbon fiber composite metal in which the spin relaxation time (T2nn) does not exist or is 1000 to 5000 μs, and the component fraction (fnn) of the component having the second spin-spin relaxation time is less than 0.2 Material manufacturing method. In any of claims 1 to 8 ,
The method for producing a carbon fiber composite metal material, wherein the flow temperature in the uncrosslinked elastomer is 20 ° C. or more higher than the flow temperature of the elastomer alone. In any one of Claim 1 thru | or 9 ,
The said process (a) 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. According to claim 1 0,
The open roll method is a method for producing a carbon fiber composite metal material in which the surface speed ratio of two rolls is 1.05 to 3.00. Oite to claim 1 1,
The said process (a) is a manufacturing method of a carbon fiber composite metal material performed at 0-50 degreeC. In any one of claims 1 to 1 2,
The carbon nanofiber is a method for producing a carbon fiber composite metal material having an average diameter of 0.5 to 500 nm. In any one of claims 1 to 1 3,
The step (b)
Disposing a metal mass above the carbon fiber composite material;
Heating and melting the metal mass to form the molten metal, vaporizing the elastomer in the carbon fiber composite material, and infiltrating the molten metal to replace the elastomer;
A method for producing a carbon fiber composite metal material, comprising:

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