JP2021042339A - Recycled carbon fiber containing resin composite and method for manufacturing the same - Google Patents

Abstract

To provide a method for manufacturing a recycled carbon fiber containing resin composite capable of inexpensively manufacturing a fiber containing resin composite excellent in sliding properties, and a recycled carbon fiber containing resin composite manufactured by the same.SOLUTION: A method for manufacturing a recycled carbon fiber containing resin composite includes manufacturing the recycled carbon fiber containing resin composite by a method for melting and mixing at least one kind selected from a group consisting of a phenol resin, an epoxy resin and a polyether ether ketone resin and recycled carbon fibers obtained by thermally decomposing carbon fiber reinforced plastic collected for recycling and having a carbon residue deposited by carbonizing the matrix component of the carbon fiber reinforced plastic.SELECTED DRAWING: Figure 3

Description

The present invention relates to a recycled carbon fiber-containing resin composite material and a method for producing the same, and more particularly to a technique for producing a composite material of carbon fiber and resin using recycled carbon fiber as a raw material.

There is an increasing demand for weight reduction of automobile parts due to the needs for improving the fuel efficiency of automobiles and expanding the cruising range due to electrification. Resin materials are attracting attention as lightweight materials that meet these requirements, and in recent years, resin materials have been used for sliding members such as gears and bearings. Further, when the sliding member is formed of a resin material, a filler such as glass fiber or carbon fiber is added to a matrix made of the resin material in order to improve the strength (for example, Patent Documents). 1).

JP-A-2018-162411

Although the sliding member formed of the resin composite material to which glass fibers are added has improved strength, it is highly aggressive to the mating material because it contains hard glass fibers, and there is a concern that the wear resistance may be lowered. To. Further, carbon fiber (virgin carbon fiber) has a drawback that it is expensive and the material cost of the sliding member is high.

As a means for reducing the cost of carbon fiber, it is conceivable to utilize recycled carbon fiber recovered from waste materials such as used carbon fiber reinforced plastic (CFRP) products and scraps produced in the production process of CFRP products. However, the recycled carbon fiber recovered in a state closer to the virgin carbon fiber is soft and fluffy like hair, and is not easy to handle. Therefore, there is a concern that the weighed recycled carbon fibers cannot be stably mixed in the matrix.

The present invention has been made in view of the above problems, and is produced by a method for producing a recycled carbon fiber-containing resin composite material, which can inexpensively produce a fiber-containing resin composite material having excellent sliding characteristics, and a method for producing the same. The main purpose is to provide a recycled carbon fiber-containing resin composite material.

The first configuration relates to a method for producing a recycled carbon fiber-containing resin composite material, which comprises at least one selected from the group consisting of phenol resin, epoxy resin and polyether ether ketone resin, and carbon fiber reinforced plastic recovered for recycling. Is obtained by thermal decomposition, and the matrix component of the carbon fiber reinforced plastic is melt-kneaded with recycled carbon fiber to which residual carbon carbonized is attached.

In the above configuration, as an inorganic filler, a relatively hard recycled carbon fiber in which residual carbon derived from the matrix component of carbon fiber reinforced plastic is attached to the surface of the carbon fiber is used as a recycled product in the matrix component of the specific resin. Manufactures carbon fiber-containing resin composite materials. According to such a manufacturing method, a recycled carbon fiber-containing resin composite material having excellent sliding characteristics can be obtained. Further, since the inorganic filler used is a recycled product, a carbon fiber-containing resin composite material having excellent sliding characteristics can be manufactured at low cost.

The recycled carbon fiber used in the above-mentioned production method is in a state where residual carbon is still attached, is not excessively opened, and has a large bulk specific gravity, so that it is easy to handle. Therefore, when the raw material is supplied to the kneading device, the recycled carbon fibers can be quantitatively charged into the kneading device, and the recycled carbon fibers in an amount corresponding to the input amount can be mixed in the matrix. That is, the supply stability of the raw material to the kneading device is excellent. Further, in the recycled carbon fiber, since the residual carbon remains attached to the carbon fiber, the cost for the treatment for recovering the carbon fiber from the carbon fiber reinforced plastic can be suppressed. This can contribute to further reduction of manufacturing cost.

The second configuration is characterized in that, in the first configuration, the recycled carbon fiber is a carbon fiber aggregate in which a large number of single fibers are aggregated. By using the carbon fiber aggregate, the handleability of the carbon fiber can be improved, and since the residual carbon is sufficiently adhered, it is suitable for increasing the mechanical strength of the recycled product. Further, the carbon fiber aggregate is lower in cost than the soft and fluffy recycled carbon fiber recovered in a state closer to the virgin carbon fiber, and a recycled product can be manufactured at a lower cost.

The third configuration is characterized in that, in the first or second configuration, the recycled carbon fiber is a primary heated product obtained by carbonizing the carbon fiber reinforced plastic at 200 to 800 ° C. In this case, the recycled carbon fiber is an aggregate of carbon fibers covered with a carbon film of residual carbon, and is excellent in handleability. It is also preferable in that the material cost can be suppressed and the recycled product can be manufactured at a lower cost.

The fourth configuration is a recycled carbon fiber-containing resin composite material containing recycled carbon fibers in a matrix consisting of at least one selected from the group consisting of a phenol resin, an epoxy resin and a polyether ether ketone resin, and the recycled carbon fiber-containing resin composite material. The carbon fibers are short fibers having a length of 10 mm or less and are non-orientedly dispersed in the matrix. Carbon, which is a product of carbonization of the matrix component of the carbon fiber reinforced plastic, is dispersed in the matrix. It is characterized by being. Since this recycled carbon fiber-containing resin composite material uses recycled carbon fiber, it is inexpensive and has excellent sliding characteristics.

The graph which shows the result of the slip wear test of the recycled carbon fiber containing PEEK composite material (PEEK-rCF) and the glass fiber containing PEEK composite material (PEEK-GF). (A) represents the wear mass of the test piece, and (b) represents the wear mass of the mating material. The figure which shows the measurement result of the dynamic friction coefficient and the sample temperature by the slip wear test. (A) is the result of the recycled carbon fiber-containing PEEK composite material, and (b) is the result of the glass fiber-containing PEEK composite material. The graph which shows the result of the slip wear test of the recycled carbon fiber-containing phenol composite material (phenol-rCF) and the glass fiber-containing phenol composite material (phenol-GF). (A) represents the wear mass of the test piece, and (b) represents the wear mass of the mating material. The figure which shows the measurement result of the dynamic friction coefficient and the sample temperature by the slip wear test. (A) is the result of the recycled carbon fiber-containing phenol composite material, and (b) is the result of the glass fiber-containing phenol composite material. The graph which shows the result of the slip wear test of the recycled carbon fiber-containing epoxy composite material (epoxy-rCF) and the glass fiber-containing epoxy composite material (epoxy-GF). (A) represents the wear mass of the test piece, and (b) represents the wear mass of the mating material. The figure which shows the measurement result of the dynamic friction coefficient and the sample temperature by the slip wear test. (A) is the result of the recycled carbon fiber-containing epoxy composite material, and (b) is the result of the glass fiber-containing epoxy composite material. The graph which shows the result of the slip wear test of the recycled carbon fiber-containing PPS composite material (PPS-rCF) and the glass fiber-containing PPS composite material (PPS-GF). (A) represents the wear mass of the test piece, and (b) represents the wear mass of the mating material.

Hereinafter, matters related to the embodiment will be described in detail. The recycled carbon fiber-containing composite material of the present embodiment is produced by a method including a step of melt-kneading the [A] resin and the [B] recycled carbon fiber.

In addition, in this specification, the numerical range described by using "~" means that the numerical value described before and after "~" is included as the lower limit value and the upper limit value. "CFRP" means an article in which a matrix component is formed of a thermosetting resin and an article in which a matrix component is formed of a thermoplastic resin.

<[A] Resin>
The resin [A] is at least one selected from the group consisting of phenol resins, epoxy resins and polyetheretherketone (PEEK) resins. Specific examples of the resin include a resol-type phenol resin, a novolak-type phenol resin, and a modified phenol resin (for example, an alkylphenol-modified phenol resin, a nitrile-modified phenol resin, a butyl etherified resol resin, a rosin-modified phenol resin, and the like. ) Etc.;
As epoxy resins, bisphenol A type epoxy resin, bisphenol F type epoxy resin, novolak type epoxy resin, glycidyl ester type epoxy resin, glycidylamine type epoxy resin, biphenyl type epoxy resin, alicyclic type epoxy resin, long chain aliphatic type Epoxy resin, brominated epoxy resin, hitandin type epoxy resin, isocyanurate type epoxy resin, etc.;
As the PEEK resin, commercially available products such as VESTAKEEP1000G, 2000G, 3300G, L4000G, 5000G (above, manufactured by Daicel Evonik), VICTREX PEEK90G, 150G, 450G, 3300G (above, manufactured by Victrex Japan) and the like are used. , Each can be mentioned. As the [A] resin, one of these types can be used alone or in combination of two or more types.

The [A] resin can be appropriately selected depending on the purpose of using the recycled carbon fiber-containing resin composite material (recycled product), and among these resins, [B] sliding by containing the recycled carbon fiber. It is more preferable that it is at least one selected from the group consisting of phenol resin and epoxy resin in terms of high effect of improving characteristics and low cost. Further, when the resin [A] is a thermosetting resin, it does not melt even at the glass transition temperature or higher, so that melting during sliding is unlikely to occur, which is preferable.

In particular, epoxy resin and phenol resin are said to be inferior in slidability to PEEK resin, but can be obtained by using [B] recycled carbon fiber as an inorganic filler added to epoxy resin or phenol resin. The recycled carbon fiber-containing resin composite material is suitable in that it exhibits sliding characteristics equivalent to those of PEEK resin. Further, the epoxy resin and the phenol resin are also excellent in that the material cost is lower than that of the PEEK resin and a material having excellent sliding characteristics can be obtained at a lower cost.

<[B] Recycled carbon fiber>
[B] Recycled carbon fiber is carbon fiber obtained by thermally decomposing carbon fiber reinforced plastic recovered for recycling (hereinafter, also referred to as "CFRP for recycling"), and is a residue due to carbonization of organic substances. Is attached to the fiber surface.

The CFRP for recycling is not particularly limited as long as it is formed of a material in which a polymer material is used as a base material (matrix component) and carbon fiber is used as a reinforcing material. As a specific example of CFRP for recycling, waste materials manufactured using virgin carbon fiber and having finished the function as a product, and waste materials such as scraps produced in the production process of the product can be used. Conventionally, such waste materials have been disposed of by landfill, incineration, etc., but it is preferable that the waste materials can be effectively utilized by manufacturing products using recycled carbon fibers, which contributes to reduction of environmental load and the like.

The carbon fibers contained in the CFRP for recycling are not particularly limited, and examples thereof include PAN-based carbon fibers and pitch-based carbon fibers. The carbon fibers in the CFRP for recycling may be continuous fibers or discontinuous fibers, and the discontinuous fibers may be short fibers or long fibers. Carbon fiber reinforced plastics using continuous fibers have already been put into practical use in aircraft members, high-pressure tanks, etc., and are being applied to automobile parts, so they are suitable because they are easily available. In the present specification, "short fiber" means a carbon fiber having a fiber length of 10 mm or less, and "long fiber" means a carbon fiber having a fiber length longer than 10 mm and 100 mm or less. "Continuous fiber" refers to continuous carbon fiber having a fiber length of more than 100 mm.

Examples of the matrix component constituting the CFRP for recycling include various polymer materials such as a thermoplastic resin, a thermosetting resin, a thermoplastic elastomer, and a thermosetting elastomer. Of these, a thermosetting resin is preferable in that a carbon fiber having a sufficient amount of residual carbon adhered to the surface can be obtained. The matrix component may be composed of only one kind of polymer material, or may be composed of two or more kinds of polymer materials.

[B] The recycled carbon fiber has a hard and stiff texture in which residual carbon derived from the matrix component of CFRP for recycling adheres to the surface of the carbon fiber. Here, the matrix component of the CFRP for recycling is sufficiently removed, and the recycled carbon fibers in a state closer to the virgin carbon fibers are soft and light like hair, and the single fibers are entangled with each other. Therefore, when the carbon fiber is supplied to the kneading device, it is difficult to supply a predetermined amount into the kneading device, and the supply stability of the raw material to the kneading device is inferior. Further, since the carbon fibers are entangled with each other, the dispersibility is poor, and there is a concern that a recycled product in which the carbon fibers are uniformly dispersed in the matrix component cannot be produced.

When soft and light recycled carbon fiber is used, it is also possible to impregnate the carbon fiber with resin and mold it into a sheet like virgin carbon fiber, and manufacture a recycled product using this sheet-shaped molded body (prepreg). Conceivable. However, in this case, both labor and cost are required. On the other hand, the [B] recycled carbon fiber used in this production method is hard because it is in a state where residual carbon is attached, and is excellent in supply stability of raw materials. Therefore, even if it is used as it is, it can be put into the kneading device in a fixed amount and is easy to handle. In addition, a composite material containing an amount of recycled carbon fiber corresponding to the amount charged in a fixed amount can be obtained, and a resin composite material having high strength can be obtained.

[B] The recycled carbon fiber is preferably a carbon fiber aggregate in which a large number of single fibers are aggregated in that it is superior in supply stability. More specifically, it is particularly preferable that the [B] recycled carbon fiber is a carbon fiber aggregate in which residual carbon serves as a binder to form a fiber bundle. [B] From the viewpoint of ease of handling, the recycled carbon fibers are preferably covered with a carbon film and have a crisp and hard texture. The shape of the carbon fiber aggregate is not particularly limited, and examples thereof include a strip shape and a plate shape.

[B] When the recycled carbon fiber is a carbon fiber aggregate, the fiber direction is not particularly limited and may be a random orientation or a regular orientation (for example, uniaxial orientation, biaxial orientation, etc.). It is preferable to have a regular fiber orientation, and more preferably a uniaxial orientation, in that the opening of the [B] recycled carbon fibers is more likely to proceed during melt-kneading.

Such [B] recycled carbon fibers can be obtained by carbonizing carbon fiber reinforced plastic at 200 to 800 ° C., more preferably 300 to 600 ° C. The carbonization is carried out by, for example, using a batch type carbonization dry distillation furnace, preferably set to a heating temperature of 400 ° C. or higher, and heating (steaming) in an oxygen-free state. The carbon fiber reinforced plastic to be carbonized may be pulverized before carbonization, but may be used as it is without being cut or pulverized as long as it can be accommodated in a carbonization carbonization furnace. The carbonization time is appropriately set according to the type and size of the carbon fiber reinforced plastic as a raw material, but is usually 3 to 24 hours, preferably 4 to 12 hours. The carbonization may be carried out while supplying superheated steam into the carbonization dry distillation furnace.

[B] As the recycled carbon fiber, it is particularly preferable to use a primary heated product obtained by the above carbonization operation. The secondary heated product obtained by further heating the primary heated product can be obtained, for example, by heating the primary heated product at 200 to 800 ° C. in an oxygen atmosphere using a firing furnace (continuous furnace). However, since the secondary heated product is soft, supple and bulky, the supply stability is inferior when it is supplied to the kneading apparatus as it is. On the other hand, since the primary heated product is hard, it has the advantages of being easy to handle and inexpensive.

[B] The amount of residual carbon (mass%) in the recycled carbon fiber is preferably 8 to 30% by mass with respect to the total amount of the matrix components in the recycled CFRP before the heat treatment. When the residual carbon content is 8% by mass or more, the handleability of the recycled carbon fiber is better and the strength of the recycled product can be sufficiently ensured, which is preferable. Further, when the residual carbon in the [B] recycled carbon fiber is 30% by mass or less with respect to the matrix component, it is preferable in that the decrease in product strength due to the excessive amount of the residual carbon can be suitably suppressed. .. From this point of view, the amount of residual carbon in the [B] recycled carbon fiber is more preferably 10 to 20% by mass, still more preferably 11.5 to 15% by mass.

<Other ingredients>
The recycled carbon fiber-containing resin composite material of the present embodiment may be produced by further using components other than the [A] resin and the [B] recycled carbon fiber, if necessary.

[A] When an epoxy resin is used as the resin, a curing agent is usually used in combination. Examples of the curing agent used together with the epoxy resin include amine-based curing agents, acid anhydride-based curing agents, polyamide-based curing agents, and imidazole-based curing agents. Among these, as the amine-based curing agent, for example, diethylenetriamine, triethylenetetramine, metaphenylenediamine, diaminodiphenylmethane, diaminodiphenylsulfone and the like; as the acid anhydride-based curing agent, for example, phthalic anhydride, pyromellitic anhydride, tetrahydro Phthalic anhydride, methyltetrahydrophthalic anhydride and the like can be mentioned respectively. [A] Examples of the curing agent used when a novolak type phenol resin is used as the resin include hexamethylenetetramine. The ratio of the curing agent used is appropriately set according to the type of the [A] resin and the curing agent, and is, for example, 30 parts by mass or less with respect to 100 parts by mass of the [A] resin.

Other components include carbon nanotubes, clay, silica particles, layered silicates (mica, mica, talc, kaolin, montmorillonite, etc.), plasticizers, colorants, mold release agents, stabilizers, and oxidations. Examples thereof include an inhibitor and a compatibilizer. The ratio of these components used can be appropriately set within a range that does not impair the effects of the present invention (for example, 0 to 5 parts by mass with respect to 100 parts by mass of the resin [A]).

<Manufacturing of recycled carbon fiber-containing resin composite material>
The recycled carbon fiber-containing resin composite material of the present embodiment can be produced by melt-kneading the [A] resin and the [B] recycled carbon fiber. Specifically, a raw material charging step of charging the [A] resin and the [B] recycled carbon fiber into the melt-kneading device, and a kneading process of melting and kneading the [A] resin and the [B] recycled carbon fiber in the melt-kneading device. It can be manufactured by a method including a step.

As the melt kneading device, a known kneading device is used, and examples thereof include a general-purpose single-screw kneader, a twin-screw kneader, a Banbury mixer, a kneader, and a high shearing machine. The melt-kneading apparatus may be a batch type or a continuous type.

In the raw material charging step, the [A] resin and the [B] recycled carbon fiber are weighed and charged into the melt-kneading apparatus at a predetermined ratio. At this time, the [A] resin and the [B] recycled carbon fiber may be charged into the melt-kneading apparatus at the same time, or may be charged separately.

The mass ratio of [A] resin and [B] recycled carbon fiber in the raw material is 10 to 60% by mass of [B] recycled carbon fiber with respect to the total amount of [A] resin and [B] recycled carbon fiber. It is preferable to do so. [B] It is preferable that the blending ratio of the recycled carbon fiber is 10% by mass or more because the mechanical strength and sliding characteristics of the recycled product can be sufficiently increased. Further, it is preferable that the blending ratio of [B] recycled carbon fiber is 60% by mass or less because the processability can be improved. The blending ratio is more preferably 15 to 55% by mass, still more preferably 20 to 50% by mass.

Further, when the ratio of [A] resin and [B] recycled carbon fiber in the raw material is expressed by the volume fraction, the blending ratio of [B] recycled carbon fiber is the same as that of [A] resin and [B] recycled carbon fiber. It is preferably 10 to 60%, more preferably 15 to 55%, and even more preferably 20 to 50% with respect to the total amount of.

[B] As the recycled carbon fiber, a commercially available product may be used as it is, but when the size is large, it may be used after being fragmented to, for example, about 2 mm to 1 cm. [B] The recycled carbon fiber is put into the melt-kneading apparatus with residual carbon adhering to the fiber surface.

The melt-kneading step is a step of mixing the [A] resin and the [B] recycled carbon fiber. The temperature at the time of melt-kneading is appropriately set according to the melt temperature of the resin [A] to be used, and is, for example, 80 to 300 ° C.

The obtained melt-kneaded product is intentionally or inevitably cooled and solidified into a desired shape. Cooling and solidification can be performed by, for example, pulverization, granulation, hot cutting, extrusion, or the like. Further, the shape of the solidified product obtained by cooling solidification may be pellet-like, powder-like, fibrous, strand-like, block-like or the like so that it can be used in the molding process, or a recycled carbon fiber-containing resin. It may be in the shape of a molded part as the final product of the material. In the molding step, the final product is obtained by performing various processing treatments such as injection molding, compression molding, extrusion molding, and laser machining using the solidified product. Both the solidified product and the final product used in the molding process correspond to "recycled fiber-containing resin composite material".

In the recycled carbon fiber-containing resin composite material obtained by the above manufacturing method, short fibrous recycled carbon fibers are dispersed in the matrix in a non-oriented manner, and residual carbon obtained by carbonizing the matrix component of CFRP for recycling is contained. It is dispersed in the matrix. This composite has high strength because the carbon fibers are dispersed in the matrix. Further, the recycled carbon fiber-containing resin composite material obtained by the above manufacturing method has excellent sliding characteristics.

That is, by melt-kneading the [A] resin and the [B] recycled carbon fibers as raw materials, the carbon fiber components of the [B] recycled carbon fibers were opened and the short fibers were non-orientedly dispersed in the matrix. A resin / carbon fiber composite material can be obtained. Further, the residual carbon constituting the [B] recycled carbon fiber is peeled from the carbon fiber by kneading, and the peeled residual carbon is refined and uniformly dispersed in the melt-kneaded product. This residual carbon functions as a filler in the resin / carbon fiber composite material, and the recycled carbon fibers are sufficiently dispersed in the melt-kneaded product by opening the fibers, resulting in high strength and excellent slidability. A resin / carbon fiber composite material can be obtained at low cost.

In the recycled carbon fiber-containing resin composite material, the length of the recycled carbon fiber is preferably 10 mm or less, more preferably 8 mm or less, and further preferably 6 mm or less. The lower limit of the length of the recycled carbon fiber is not particularly limited, but is, for example, 1 mm or more. The size and shape of the residual carbon in the recycled carbon fiber-containing resin composite material are not particularly limited. The size of the residual carbon exfoliated from the carbon fiber and refined is preferably 7 μm or less, more preferably 2 μm or less, when expressed by the longest length connecting two different outer edges of the residual carbon. .. The lower limit of the size of residual carbon is not particularly limited, but is, for example, 0.001 μm or more. The thickness of the residual carbon adhering to the surface of the carbon fiber in the form of a film is not particularly limited with respect to the lower limit, but is preferably 0.1 μm or more, and more preferably 1 μm or more and 10 μm or less.

The reason why the recycled carbon fiber-containing resin composite material of the present invention is excellent in slidability is not clear, but one hypothesis is that it remains on the recycled carbon fiber in the recycled carbon fiber-containing resin composite material and its surface. It is presumed that the carbonized material has the property of improving the slidability. As a result, its own wear resistance is improved, and when it comes into contact with the mating material, in addition to the above characteristics, wear powder containing residual carbon intervenes in the contact surface to attack the mating material. It is presumed that the material has reduced properties, and as a result, the material has excellent sliding characteristics. It should be noted that this guess does not limit the present invention.

The recycled carbon fiber-containing resin composite material of the present invention can be applied to various uses. Specifically, for example, various parts of moving bodies such as automobiles, ships and railroad vehicles; sports parts such as rackets, golf shafts, fishing rods and sticks; aerospace parts such as fuselage, main wings and tail wings; drive shafts and plates. Industrial machine parts such as springs, flywheels, rollers, cables, repair reinforcements; building materials such as roofing materials and wall materials; materials for information terminal equipment such as housings, pellets, sheets, films, fibers , Strands and other intermediate products or raw materials.

Further, since the recycled carbon fiber-containing resin composite material of the present invention has excellent sliding characteristics, it can be particularly preferably applied as a sliding member for various purposes such as automobile parts, electrical and electronic parts, and home appliance parts. The sliding member is not particularly limited, and examples thereof include gears, cams, bearings, pulleys, valves, valve seats, pistons, piston rings, mechanical seals, and the like.

Short fiber pellets are useful as materials for mass production of parts with complex shapes by injection molding. In particular, according to the above manufacturing method, pellets containing carbon fiber, which is generally said to be expensive, can be manufactured at low cost, the material cost of the product can be suppressed, and a product having excellent slidability can be obtained. It is excellent in that it can be done.

Hereinafter, the present invention will be described in more detail with reference to Examples, but the present invention is not limited to these Examples. In addition, "part" and "%" in Examples and Comparative Examples are based on mass unless otherwise specified.

[Example 1]
1. 1. Manufacture of Recycled Carbon Fiber-Containing Resin Composite Material Recycled carbon fiber (primary heated product manufactured by Carbon Fiber Recycle Industry Co., Ltd.) was cut to a width of about 3 mm. The cut recycled carbon fiber and PEEK resin (manufactured by Daicel Ebonic) are used in a normal biaxial manner so that the blending amount of the recycled carbon fiber is 30% by mass with respect to the total amount of the PEEK resin and the recycled carbon fiber. It was put into a kneader and melt-kneaded to be pelletized. Using this pellet as a raw material, it is molded into a plate of 80 mm × 80 mm × 2.0 mm by an injection molding machine, and a plate of 30 mm × 30 mm × 2.0 mm is cut out from the center of the plate, and slip wear of the recycled carbon fiber-containing PEEK composite material is obtained. A square plate test piece for evaluation was prepared.

2. Evaluation of sliding characteristics (evaluation of sliding wear)
Above 1. A slip wear test was carried out in accordance with the JIS K 7218 A method using the square plate test piece prepared in the above, and the wear mass [mg] of the test piece and the mating material was measured. The measurement was performed under the following conditions.
(Measurement condition)
Measuring device: A & D friction and wear tester MODEL EMF-III-F
Slip speed: 1.0 m / s, load: 100 N
Test time: 100 minutes, measurement environment temperature: 23 ° C
Mating material: S45C rotating hollow cylinder (surface roughness about 0.8 μm Ra, contact area 2 cm ² )
The measurement result of the wear mass is shown in FIG. The wear mass was the mass difference between the sample before the test and the sample after the test. In this embodiment, the slip wear test is performed three times, and the average value of the test piece wear mass obtained by the three measurements is shown in FIG. 1 (a) as the measurement result, which is arbitrary among the three wear tests. The wear mass of the mating material obtained by one measurement of is shown in FIG. 1 (b) as a measurement result. In FIG. 1, (a) is the wear mass [mg] of the test piece (composite material), and (b) is the wear mass [mg] of the mating material (also in FIGS. 3, 5 and 7 below). the same).

[Comparative Example 1]
Commercially available glass fiber-containing PEEK composite material (manufactured by Daicel Ebonic, product number 2000GF30, glass fiber content = 30% by mass) Cut from the center of a 100 mm × 100 mm × 3.0 mm flat plate, 30 mm × 30 mm × 3.0 mm The glass fiber-containing PEEK composite material was prepared as a square plate test piece for slip wear evaluation. Further, using the obtained square plate test piece, a slip wear test was conducted in the same manner as in Example 1. The result is shown in FIG.

As can be seen from FIG. 1, in the recycled carbon fiber-containing PEEK composite material of Example 1, the wear mass of the test piece was significantly reduced as compared with the glass fiber-containing PEEK composite material of Comparative Example 1 (FIG. 1 (a)). reference). In addition, the wear mass of the mating material was also reduced in Example 1 as compared with Comparative Example 1.

(Measurement of dynamic friction coefficient and sample temperature)
FIG. 2 shows the results of monitoring the kinematic friction coefficient and the time-dependent changes in the sample temperature for each of the arbitrary 1 test pieces of Example 1 and Comparative Example 1. The sample temperature was measured by installing a thermocouple for temperature measurement on the mating material cylinder in contact with the test piece and measuring the temperature during the test.

As can be seen by comparing FIG. 2 (a) and FIG. 2 (b), in Example 1, although the dynamic friction coefficient and the temperature fluctuated greatly at the beginning of the measurement, the dynamic friction coefficient and the temperature became stable with the passage of time. On the other hand, in Comparative Example 1, the coefficient of kinetic friction fluctuated continuously and was unstable. Further, in Comparative Example 1, the sample temperature rose sharply immediately after the start of measurement as compared with Example 1.

[Example 2]
1. 1. Manufacture of Recycled Carbon Fiber-Containing Resin Composite Material Recycled carbon fiber (primary heated product manufactured by iCarbon) was cut to a width of about 4 mm. The amount of the cut recycled carbon fiber and the novolak type phenol resin (manufactured by Sumitomo Bakelite Co., Ltd.) is 35% (body integration rate) of the total amount of the phenol resin and the recycled carbon fiber. It was melt-kneaded with a curing agent (hexamine) using a roll, and partially cured and granulated. Subsequently, using these granules as a raw material, they are molded and cured into a plate of 60 mm × 60 mm × 2.0 mm by an injection molding machine, and a plate of 30 mm × 30 mm × 2.0 mm is cut out from the central portion thereof, and recycled carbon fiber-containing phenol is obtained. A square plate test piece for evaluating slip wear of a composite material was prepared.

2. Evaluation of sliding characteristics (evaluation of sliding wear)
Above 1. The wear mass [mg] of the test piece and the mating material was measured in the same manner as in Example 1 using the square plate test piece prepared in 1. The result is shown in FIG.

[Comparative Example 2]
A glass fiber-containing phenol composite material (manufactured by Sumitomo Bakelite Co., Ltd., glass fiber content = 35% (volume fraction)) is molded into a flat plate of 60 mm × 60 mm × 2.0 mm by an injection molding machine, and cut from the center. A glass fiber-containing phenol composite having a size of 30 mm × 30 mm × 2.0 mm was prepared as a square plate test piece for slip wear evaluation. Further, using the obtained square plate test piece, a slip wear test was conducted in the same manner as in Example 1. The result is shown in FIG.

As can be seen from FIG. 3, in the recycled carbon fiber-containing phenol composite material of Example 2, the wear mass of the test piece was significantly reduced as compared with the glass fiber-containing phenol composite material of Comparative Example 2 (FIG. 2A). reference). This amount of decrease was larger than that of Example 1 using PEEK resin. In addition, the wear mass of the mating material was also significantly reduced in the recycled carbon fiber-containing phenol composite material of Example 2 as compared with Comparative Example 2, and was a very small amount. From these results, by dispersing [B] recycled carbon fiber in phenol resin, it is possible to inexpensively obtain a material having the same slidability as PEEK resin in phenol resin which is inferior in slidability to PEEK resin. Can be said to be possible.

(Measurement of dynamic friction coefficient and sample temperature)
FIG. 4 shows the results of monitoring the kinematic friction coefficient and the time-dependent changes in the sample temperature for each of the arbitrary 1 test pieces of Example 2 and Comparative Example 2.

Comparing FIG. 4 (a) and FIG. 4 (b), the recycled carbon fiber-containing phenol composite of Example 2 has either a dynamic friction coefficient or a sample temperature as compared with the glass fiber-containing phenol composite of Comparative Example 2. Also showed a low value. Further, in the composite material of Example 2, the fluctuations in the dynamic friction coefficient and the sample temperature were smaller and more stable than those in the composite material of Comparative Example 2.

[Example 3]
1. 1. Manufacture of Recycled Carbon Fiber-Containing Resin Composite Material Recycled carbon fiber (primary heated product manufactured by iCarbon) was cut to a width of about 4 mm. The cut recycled carbon fiber and the epoxy resin (manufactured by Cluster Technology Co., Ltd., equivalent to product number J103) are mixed so that the blending amount of the recycled carbon fiber is 30% by mass with respect to the total amount of the epoxy resin and the recycled carbon fiber. It was melt-kneaded together with an additive (including a curing agent), partially cured and granulated. Using these granules as a raw material, they are molded and cured into a plate of 80 mm × 80 mm × 2.0 mm by a compression molding machine, and a plate of 30 mm × 30 mm × 2.0 mm is cut out from the center of the plate to obtain a recycled carbon fiber-containing epoxy composite material. A square plate test piece for slip wear evaluation was prepared.

2. Evaluation of sliding characteristics (evaluation of sliding wear)
Above 1. The wear mass [mg] of the test piece and the mating material was measured in the same manner as in Example 1 using the square plate test piece prepared in 1. The result is shown in FIG.

[Comparative Example 3]
Perform the same operation as in Example 3 except that glass fiber (commercially available standard product) was used instead of recycled carbon fiber, and slide a 30 mm × 30 mm × 2.0 mm glass fiber-containing epoxy composite material into a corner for slip wear evaluation. It was prepared as a plate test piece. Further, using the obtained square plate test piece, a slip wear test was conducted in the same manner as in Example 1. The result is shown in FIG.

As is clear from FIG. 5, in the recycled carbon fiber-containing epoxy composite material of Example 3, the wear mass of the test piece was significantly reduced as compared with the glass fiber-containing epoxy composite material of Comparative Example 3 (FIG. 3 (a). )reference). This amount of decrease was very large as compared with Example 1 using PEEK resin. In addition, the wear mass of the mating material was also significantly reduced in the recycled carbon fiber-containing epoxy composite material of Example 3 as compared with Comparative Example 3, and was the same value as in the case of PEEK resin (see FIG. 1 (b)). there were. From these results, by dispersing [B] recycled carbon fiber in the epoxy resin, it is possible to inexpensively obtain a material having the same sliding characteristics as the PEEK resin in the epoxy resin having inferior slidability as compared with the PEEK resin. I found that I could do it.

(Measurement of dynamic friction coefficient and sample temperature)
FIG. 6 shows the results of monitoring the kinematic friction coefficient and the time-dependent changes in the sample temperature for each of the arbitrary 1 test pieces of Example 3 and Comparative Example 3.

Comparing FIG. 6A and FIG. 6B, the recycled carbon fiber-containing epoxy composite material of Example 3 has either a dynamic friction coefficient or a sample temperature as compared with the glass fiber-containing epoxy composite material of Comparative Example 3. Also showed a low value. Further, it was shown that in the composite material of Example 3, the fluctuations in the dynamic friction coefficient and the sample temperature were very small, and the stick slip was small.

[Comparative Example 4]
Using polyphenylene sulfide (PPS) resin (manufactured by Toray Industries, Inc., low-viscosity grade) instead of PEEK resin, the same operation as in Example 1 was performed except that the blending ratio of recycled carbon fiber was 40% by mass, and 30 mm × 30 mm. A PPS composite material containing recycled carbon fiber of × 2.0 mm was prepared as a square plate test piece for slip wear evaluation. Further, using the obtained square plate test piece, a slip wear test was conducted in the same manner as in Example 1. The result is shown in FIG.

[Comparative Example 5]
The same operation as in Example 1 was performed except that a commercially available glass fiber-containing PPS composite material (manufactured by Toray, product number Trerina A604B, glass fiber content = 40% by mass) was used, and the size was 30 mm × 30 mm × 2.0 mm. A glass fiber-containing PPS composite material was prepared as a square plate test piece for slip wear evaluation. Further, using the obtained square plate test piece, a slip wear test was conducted in the same manner as in Example 1. The result is shown in FIG.

Regarding the wear mass of the test piece and the mating material obtained by the slip wear test of each example, the reduction rate of the wear mass when the inorganic filler in each resin is replaced with [B] recycled carbon fiber ΔR [% ] Was calculated by the following formula (1) and shown in Table 1.
ΔR = [(Q2-Q1) / Q2] × 100 ・ ・ ・ (1)
(In the formula (1), Q1 represents the wear mass of the recycled carbon fiber-containing resin composite material of Examples 1 to 3 and Q2 represents the wear mass of the glass fiber-containing resin composite material of Comparative Examples 1 to 3).
The larger the reduction rate ΔR, the greater the effect of improving the wear resistance and low aggression of the [B] recycled carbon fiber, and the better the sliding characteristics of the composite material. Table 1 also shows the wear mass [mg] of the test piece (composite material) and the mating material.

As shown in Table 1, when PEEK resin, phenol resin or epoxy resin was used as the matrix component, the value of the reduction rate ΔR of the composite material was larger than that when PPS resin was used. In particular, when phenol resin and epoxy resin are used, the reduction rate ΔR of the composite material is very large, 84% and 92%, and the effect of improving the wear resistance by using [B] recycled carbon fiber is high. It was. Further, when the phenol resin and the epoxy resin were used, the reduction rate ΔR of the mating material also showed a very large value, and the aggression against the mating material was also low. When PEEK resin was used, the reduction rate ΔR of the mating material was as low as 25%, but the wear mass was very small as 0.12 mg.

From the above results, it is clear that a recycled product having excellent sliding characteristics can be inexpensively produced by the method of melt-kneading at least one of phenol resin, epoxy resin and PEEK resin with [B] recycled carbon fiber. It was.

Claims (4)

It is obtained by thermally decomposing at least one selected from the group consisting of phenol resin, epoxy resin and polyether ether ketone resin and carbon fiber reinforced plastic recovered for recycling, and the matrix component of the carbon fiber reinforced plastic is obtained. A method for producing a recycled carbon fiber-containing resin composite material, in which recycled carbon fibers to which carbonized residual carbon is attached are melt-kneaded. The method for producing a recycled carbon fiber-containing resin composite material according to claim 1, wherein the recycled carbon fiber is an aggregate of carbon fibers in which a large number of single fibers are aggregated. The method for producing a recycled carbon fiber-containing resin composite material according to claim 1 or 2, wherein the recycled carbon fiber is a primary heated product obtained by drying the carbon fiber reinforced plastic at 200 to 800 ° C. A recycled carbon fiber-containing resin composite material containing recycled carbon fibers in a matrix consisting of at least one selected from the group consisting of phenol resins, epoxy resins and polyetheretherketone resins.
The recycled carbon fibers are short fibers having a length of 10 mm or less, and are dispersed in the matrix in a non-oriented manner.
A recycled carbon fiber-containing resin composite material in which carbon, which is a product of carbonization of a matrix component of carbon fiber reinforced plastic, is dispersed in the matrix.

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