JP2016124742A - Plate shape carbon molded body - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a part that can easily be processed into a desired shape, does not require a high production cost, as well as that has a uniform mechanical strength.SOLUTION: A plate shape carbon molded body contains amorphous carbon, as well as fibrous and/or flat-shape carbon filler dispersed therein, as well as in which, when measured in accordance with JISK7074, the flexural strength in a direction at which the flexural strength is minimum, is at least 80% of the flexural strength in a direction at which the flexural strength is maximum.SELECTED DRAWING: Figure 3

Description

  The present invention relates to a plate-like carbon molded body.

  As a part of the machine element, various carbon molded bodies using a carbon material are used. The carbon molded body is required to take various forms depending on the place of use and application. In addition, these parts are molded by various methods.

  Patent Document 1 discloses a coil spring made of a ceramic / carbon composite material, specifically, a material obtained by converting all or part of a carbon material into silicon carbide. This coil spring is formed by extruding this composite material and winding a linear carbon molded body obtained by molding.

  Patent Document 2 discloses a washer made of a carbon fiber / carbon composite material, specifically, a material made of carbon fiber and amorphous carbon surrounding the carbon fiber. This washer is made of a raw preformed yarn in the form of a yarn, tape or sheet, wound around a core rod together with a gap holding coil material, arranged alternately with the raw preformed yarn and the coil material, and then hot-pressed. Molding is performed by removing the coil material from the molded body thus obtained, then carbonizing, then graphitizing, and cutting the carbon molded body every round.

Japanese Patent Laid-Open No. 1-183413 JP-A-8-42550

  As described above, the carbon molded body is required to take various forms depending on the place of use and application. For example, when used as a battery component or conductive contact, it may be necessary to take the form of a leaf spring. However, the carbon molded body disclosed in the above-mentioned patent document requires a complicated process as described above, and depending on the form of the carbon molded body, a process of cutting it after being manufactured in the form of a block is required. It was something to do.

  In addition, the carbon molded body using the ceramic of Patent Document 1 is fragile because it has poor thermal shock resistance and toughness.

  Moreover, since the carbon fiber / carbon composite material of Patent Document 2 is very expensive and the carbon fibers are oriented in a specific direction, the mechanical strength of the produced carbon molded body depends on the measurement direction. Different evaluation results were shown.

  Therefore, in this invention, the plate-shaped carbon molded object which shows uniform mechanical strength in a surface direction is provided.

  In addition, parts using carbon composite materials have problems with metal parts, such as deterioration of performance due to metal fatigue when used over a long period of time, and corrosion when used in an environment where they can come into contact with electrolyte. It has the advantage that it does not have the problem which arises and the problem which a deformation | transformation and deterioration generate | occur | produce when used in a high temperature environment.

As a result of intensive studies, the present inventors have found that the above problems can be solved by the following means, and have completed the present invention. That is, the present invention is as follows:
<1> A direction in which bending strength is minimum when it contains amorphous carbon and fibrous and / or flat carbon fillers dispersed in the amorphous carbon and is measured according to JIS K7074. The bending strength at 80% or more of the bending strength in the direction in which the bending strength is maximum,
Plate-like carbon molded body.
<2> The plate-like carbon molded article according to <1>, which is a leaf spring.
<3> When a sliding test was conducted using a SUJ-2 ball with a ball-on-disk friction and wear tester under the conditions of a load of 300 gf, a rotational radius of 12 mm, a rotational speed of 5 m / min, and a sliding distance of 5000 m. The plate-like carbon molded body according to <1> or <2>, wherein the average friction coefficient of the entire space is 0.15 or less.
<4> The plate-like carbon molded article according to any one of <1> to <3>, wherein the thickness is 1.0 mm or less.
<5> The plate-like carbon molded body according to any one of <1> to <4>, wherein the amorphous carbon is generated by carbonizing the binder resin in a non-oxidizing atmosphere.
<6> The plate-like carbon molded article according to <5>, wherein the binder resin is a thermosetting resin.
<7> The plate shape according to any one of <1> to <6>, wherein the carbon filler is one of graphite, milled fiber, chopped fiber, and carbon nanotube, or a combination thereof. Carbon molded body.
<8> The plate-shaped carbon molded body according to any one of <1> to <7>, wherein the content of the carbon filler is 30% by mass or less.
<9> providing a composition for a carbon molded body containing a liquid curable resin and a carbon filler;
Pouring the composition for carbon molded body into a mold, and curing the liquid curable resin to obtain a plate-shaped cured resin molded body, and carbonizing the plate-shaped cured resin molded body, A method for producing a plate-like carbon molded body.
<10> The liquid curable resin is partially cured to form a plate-shaped semi-cured resin molded body, and the plate-shaped semi-cured resin molded body is deformed and / or cut and deformed, and The method according to <9>, wherein the plate-shaped semi-cured resin molded body is cured to form the plate-shaped cured resin molded body.

  ADVANTAGE OF THE INVENTION According to this invention, the plate-shaped carbon molded object which can be processed into a desired shape easily, does not require high manufacturing cost, and has uniform mechanical strength can be provided.

It is a schematic diagram of the orientation of the carbon filler in the plate-shaped carbon molded object of this invention. It is a schematic diagram of the orientation of the carbon filler in the prior art carbon molded body. It is a figure which shows the relationship between the load and deflection amount before and after the repetition test of the leaf | plate spring of Example 1. FIG.

<Plate-shaped carbon compact>
The plate-like carbon molded body of the present invention includes amorphous carbon and a carbon filler dispersed in the amorphous carbon.

<Amorphous carbon>
Amorphous carbon may be obtained, for example, by carbonizing a binder resin in a non-oxidizing atmosphere.

<Carbon filler>
The carbon filler refers to a fibrous and / or flat carbon filler dispersed in amorphous carbon.

  Examples of the fibrous carbon filler include, but are not limited to, milled fiber and chopped fiber. These may be used alone or in combination.

  The average length of the fibrous carbon filler can be 1 μm or more, 3 μm or more, 5 μm or more, 10 μm or more, or 15 μm or more, and can be 100 μm or less, 70 μm or less, 50 μm or less, or 30 μm or less.

  Examples of the flat carbon filler include graphite and carbon nanotubes. These may be used alone or in combination.

  The particle size of the flat carbon filler can be 1 μm or more, 2 μm or more, or 3 μm or more, and can be 20 μm or less, 15 μm or less, 10 μm or less, or 7 μm or less.

  The carbon filler content in the mixture can be 30% or less, 25% or less, 20% or less, or 15% or less, and can be 5% or more, 7% or more, or 10% or more. it can. When the content of the carbon filler is 30% or less, the carbon molded body can be molded more easily. Moreover, when the content of the carbon filler is 5% or more, good mechanical properties of the molded part can be ensured.

  The carbon filler is not oriented in one direction in the carbon molded body, thereby providing a plate-like carbon molded body having uniform mechanical strength.

<Bending strength>
The bending strength of the plate-like carbon molded body in the direction where the bending strength is minimum is 80% or more, 85% or more, 90% or more, 95% or more of the bending strength in the direction where the bending strength is maximum, or It can be 100%.

Here, the bending strength is measured based on JIS K7074. Specifically, a load (three-point bending) is applied to one point of a test piece that is simply supported at both ends, the test piece is deflected at a predetermined test speed, and a load-deflection curve is recorded. The maximum load P _b (N) applied to the piece is obtained, and the bending strength σ _b (MPa) obtained by the following equation is thereby obtained.
σ _b = (3P _b L / 2bh ² ) × {1 + 4 (δ / L) ² }
Wherein, L is distance between fulcrums (mm), b is the width of the test piece (mm), h is the thickness of the test piece (mm), [delta] denotes the deflection at the load _{P b} (mm). Here, it should be noted that the measurement can be performed by cutting the test piece into arbitrary sizes.

  The form of the plate-like carbon molded body can be any form, for example, a form of a leaf spring.

  The average friction coefficient of the plate-like carbon molded body can be 0.20 or less, 0.17 or less, or 0.15 or less, and is 0.05 or more, 0.07 or more, or 0.10 or more. be able to.

  Here, the average friction coefficient is obtained when a sliding test is performed using a SUJ-2 ball with a ball-on-disk friction and wear tester under the conditions of a load of 300 gf, a rotational radius of 12 mm, a rotational speed of 5 m / min, and a sliding distance of 5000 m. This is the average friction coefficient of the whole during sliding.

  The volume specific resistance of the plate-like carbon molded body can be 0.0100 Ω · cm or less, 0.0070 Ω · cm or less, or 0.0050 Ω · cm or less, and 0.0001 Ω · cm or more, 0.0005 Ω · cm or less. cm or more, or 0.0010 Ω · cm or more.

  Here, the volume resistivity refers to the volume resistivity measured by the 4-terminal method.

  The thickness of the leaf spring can be 1.0 mm or less, 0.8 mm or less, or 0.7 mm or less, and can be 0.1 mm or more, 0.3 mm or more, or 0.5 mm or more.

<< Manufacturing method of plate-like carbon compact >>
The method for producing a plate-shaped carbon molded body of the present invention provides a composition for a carbon molded body containing a liquid curable resin and a carbon filler, pouring the carbon molded body composition into a mold, and It includes curing the curable resin to obtain a plate-shaped cured resin molded body, and carbonizing the plate-shaped cured resin molded body.

  The method of the present invention will be described below with reference to FIGS. In these figures, it is assumed that a fibrous carbon filler is used, but it should be noted that the same theory can be applied even when a flat carbon filler is used.

  In the conventional carbon molded body, as shown in FIG. 2, the carbon filler (10) is dispersed in the resin (20). When the carbon filler is extruded, the carbon filler ( 10) will be oriented.

  In contrast, in the plate-like carbon molded body of the present invention, a composition for a carbon molded body in which the carbon filler (10) is dispersed in the liquid curable resin (20) as shown in FIG. Used and poured into the formwork. Therefore, the problem of orientation of the carbon filler as in the prior art does not occur. Moreover, when a carbon filler is flat shape, the same surface of a carbon filler will not face the same side.

  In the method of the present invention, since the carbon filler is not oriented in one direction, the variation in mechanical strength in the direction with the maximum carbon bending strength and the direction with the minimum bending strength can be suppressed. As a result, the uniformity of the mechanical strength of the plate-like carbon molded body can be ensured.

  The liquid curable resin used in the method of the present invention may be a thermosetting resin or an ultraviolet curable resin.

  Examples of the thermosetting resin include, but are not limited to, thermosetting resins such as phenol resin, furan resin, imide resin, epoxy resin, and unsaturated polyester resin. These may be used singly or in combination of two or more.

  The composition for carbon molded bodies can contain an optional additive as long as the object of the present invention is not impaired. Examples of the additive include a curing agent.

  Carbonization can be performed by raising the temperature in a non-oxidizing atmosphere such as nitrogen or argon, holding at the carbonization holding temperature, and naturally cooling.

  The heating rate can be 10 ° C / h or more, 15 ° C / h or more, 20 ° C / h or more, and 100 ° C / h or less, 90 ° C / h or less, or 80 ° C / h or less. be able to.

  The carbonization holding temperature can be 700 ° C. or higher, 750 ° C. or higher, or 800 ° C. or higher, and can be 1500 ° C. or lower, 1450 ° C. or lower, or 1400 ° C. or lower.

  The present invention will be specifically described with reference to Examples and Comparative Examples, but the present invention is not limited to these.

<Example 1>
90 parts of furan resin (VF-303 manufactured by Hitachi Chemical Co., Ltd.) as an amorphous carbon source and 10 parts of natural scaly graphite (Nippon graphite average particle diameter 5 μm) as a carbon filler are stirred with a pony mixer or the like, and then a curing agent. 1 part of p-toluenesulfonic acid is added, and sufficiently stirred using a high-speed emulsifier / disperser (Primics Co., Ltd. Homomixer MARK II 2.5 type), and subjected to vacuum defoaming operation. A composition was obtained.

  The composition for carbon molded body was poured into a 0.7 mm thick mold and cured by applying heat to prepare a resin sheet as a semi-cured resin molded body. This sheet was cut into a width of 10 mm and a length of 100 mm, and placed in a mold for imparting a spring shape and deformed.

  Thereafter, the cut and deformed semi-cured resin molded body was dried at 180 ° C. for 3 hours and treated at 1000 ° C. for 3 hours in a nitrogen atmosphere to obtain a leaf spring having a thickness of 0.5 mm.

<Example 2>
98 parts of furan resin (VF-303 manufactured by Hitachi Chemical Co., Ltd.) as an amorphous carbon source, and vapor-grown carbon fiber (VGCF-H manufactured by Showa Denko Co., Ltd., average fiber diameter of 0.2 μm or less and average fiber length of 20 μm) as a carbon filler A leaf spring having a thickness of 0.5 mm was obtained in the same manner as in Example 1 except that 2 parts were used.

<Example 3>
90 parts of furan resin (VF-303 manufactured by Hitachi Chemical Co., Ltd.) as an amorphous carbon source, 10 parts of pitch-based graphitic carbon fiber (HC600-100M manufactured by Nippon Graphite Fiber, average fiber diameter 7 μm, average fiber length 100 μm) as carbon filler A leaf spring having a thickness of 0.5 mm was obtained in the same manner as in Example 1 except that was used.

<Comparative example 1>
40 parts of vinyl chloride resin as an amorphous carbon source, 20 parts of furan resin (VF-303 manufactured by Hitachi Chemical Co., Ltd.), natural scaly graphite (average particle diameter of 5 μm made by Nippon Graphite) as a carbon filler, and pitch-based graphite After adding a diallyl phthalate monomer as a plasticizer to 10 parts of carbonaceous carbon fiber (HC600-100M manufactured by Nippon Graphite Fiber, average fiber diameter 7 μm, average fiber length 100 μm) and dispersing with a Henschel mixer, three rolls The mixture was kneaded and pelletized with a pelletizer.

  The obtained pellets were formed into a sheet by an extruder having a slit die having a slit width of 1 mm and a width of 34 mm, and treated in an air oven at 180 ° C. for 3 hours to obtain a carbon precursor. Thereafter, the temperature was raised at 15 ° C. per hour in a nitrogen atmosphere and held at 1000 ° C. for 3 hours to obtain a plate material having a thickness of 0.7 mm.

<Evaluation>
The average friction coefficient, specific resistance, and durability of Example 1 and the bending strengths of Examples 1 to 3 and Comparative Example 1 were evaluated as described below.

(Average friction coefficient)
The sheet material obtained for Example 1 was cut into a width of 50 mm and a length of 50 mm as test pieces, and the friction coefficient and specific wear amount were measured using a ball-on-disk friction and wear tester. A sliding test was performed under the conditions of a radius of 12 mm, a rotational speed of 5 m / min, and a sliding distance of 5000 m. The average coefficient of friction was 0.15.

(Specific resistance)
About Example 1, when the volume specific resistance was calculated | required by the 4 terminal method from the test piece of 50 mm x 3 mm x 0.5 mm, it was 0.0038 ohm * cm.

(durability)
About Example 1, durability evaluation by a repeated test was implemented using the test piece of 50 mm x 3 mm x 0.5 mm. Specifically, a process of applying a load to the leaf spring 1 million times is performed, and the relationship between the load and the deflection amount before and after this process is evaluated. The relationship between the load and the amount of deflection before and after the repeated test is shown in FIG. From FIG. 1, it will be understood that the leaf spring of Example 1 has the same relationship between the load and the amount of deflection even after the load is applied 1 million times, that is, the performance is not deteriorated due to fatigue.

(Bending strength)
For Examples 1 to 3 and Comparative Example 1, in accordance with JIS K 7074, the bending strength in the direction in which the bending strength of the test piece is maximum (maximum direction) and the direction in which the bending strength is minimum (minimum direction). It was measured. The evaluation results are shown in Table 1.

  From Table 1, the leaf springs of Examples 1 to 3 are 100% of the bending strength in the direction where the bending strength is minimum, and the orientation is oriented. It will be understood that there is no difference in the resulting mechanical strength.

10 Carbon fiber 20 Resin (amorphous carbon source)

Claims (10)

Bending in the direction in which bending strength is minimum when it contains amorphous carbon and fibrous and / or flat carbon filler dispersed in the amorphous carbon and is measured according to JIS K7074 The strength is 80% or more of the bending strength in the direction in which the bending strength is maximum,
Plate-like carbon molded body.   The plate-like carbon molded body according to claim 1, which is a leaf spring.   When a sliding test was conducted using a SUJ-2 ball on a ball-on-disk friction and wear tester under the conditions of a load of 300 gf, a rotational radius of 12 mm, a rotational speed of 5 m / min, and a sliding distance of 5000 m, The plate-shaped carbon molded object of Claim 1 or 2 whose average friction coefficient is 0.15 or less.   The plate-shaped carbon molded object as described in any one of Claims 1-3 whose thickness is 1.0 mm or less.   The plate-like carbon molded body according to any one of claims 1 to 4, wherein the amorphous carbon is generated by carbonizing the binder resin in a non-oxidizing atmosphere.   The plate-like carbon molded body according to claim 5, wherein the binder resin is a thermosetting resin.   The plate-like carbon molded body according to any one of claims 1 to 6, wherein the carbon filler is one of graphite, milled fiber, chopped fiber, and carbon nanotube, or a combination thereof.   The plate-shaped carbon molded object as described in any one of Claims 1-7 whose content of the said carbon filler is 30 mass% or less. Providing a composition for a carbon molded body containing a liquid curable resin and a carbon filler;
Pouring a composition for carbon molded body into a mold, and curing the liquid curable resin to obtain a plate-shaped cured resin molded body, and carbonizing the plate-shaped cured resin molded body, A method for producing a plate-like carbon molded body.   The liquid curable resin is partially cured to form a plate-shaped semi-cured resin molded body, the plate-shaped semi-cured resin molded body is deformed and / or cut, and deformed and / or cut. The method according to claim 9, wherein the plate-shaped semi-cured resin molded body is cured to form the plate-shaped cured resin molded body.

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