JP2003062829A - Method for producing pellet containing carbon fiber, pellet containing carbon fiber, and resin composition for molding - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain pellets containing carbon fibers with the dispersibility of carbon fibers during molding improved when the pellets are produced by an emulsion immersion method using a thermoplastic resin emulsion having a resin solid content of a diene-ethylene copolymer which is obtained from a diene monomer and a monomer having an ethylenic double bond and has a glass transition temperature of 20 deg.C or higher. SOLUTION: The temperature of the thermoplastic resin emulsion in which a continuous carbon fiber bundle is immersed is set up at 30-80 deg.C, and the amount of the resin solid content to be adhered to the fiber bundle is adjusted to be at least 30 wt.%.

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to a method for producing a carbon fiber-containing pellet used for molding a resin molded product reinforced with carbon fiber, a carbon fiber-containing pellet obtained by the method, a carbon fiber-containing pellet and a heat-resistant pellet. The present invention relates to a molding resin composition containing a plastic resin.

[0002]

2. Description of the Related Art Conventionally, as a method for producing pellets containing reinforcing fibers, which are excellent in dispersibility of reinforcing fibers in a molded product, generate few free fibers, and hardly discolor, a diene monomer and an ethylenic unsaturated A diene having a glass transition point of 20 ° C. or higher obtained by copolymerization with a monomer having a double bond
Using a thermoplastic resin emulsion having an ethylene copolymer as a resin solid content, the continuous fiber bundle is immersed in the thermoplastic resin emulsion bath, and the continuous fiber bundle to which the thermoplastic resin emulsion is attached is transferred to the diene-ethylene copolymer. The polymer is dried at a glass transition point to a temperature of 300 ° C., and the diene-ethylene copolymer is melted and adhered so that the amount of the diene-ethylene copolymer attached to the fiber is 5 or less.
An emulsion dipping method is known in which a reinforcing fiber-containing pellet is produced by cutting a continuous fiber bundle having a weight percentage of at least 1 into a predetermined length (Japanese Patent Laid-Open No. 2000-167828).

[0003]

By the way, the conventional production method described in the above-mentioned publication is intended for a wide range of reinforcing fibers including not only carbon fibers but also glass fibers, aromatic polyamide fibers and aromatic polyester fibers. In addition, the publication does not disclose the temperature of the thermoplastic resin emulsion when dipping the continuous fiber bundle.

On the other hand, the conventional manufacturing method described above is applied to carbon fibers while the temperature of the thermoplastic resin emulsion used is less than 30 ° C., and the obtained carbon fiber-containing pellets are used to mold the resin reinforced with carbon fibers. When a product is molded, there is a problem that the carbon fibers are insufficiently dispersed depending on the shape of the molded product.

The present invention has been made in view of the above-mentioned problems of the prior art, and comprises a diene monomer and a monomer having an ethylenically unsaturated double bond as a monomer component, and a glass transition point of 20 ° C. When producing carbon fiber-containing pellets by an emulsion dipping method using a thermoplastic resin emulsion having the above-mentioned diene-ethylene copolymer as a resin solid content, carbon fibers further improved in dispersibility of carbon fibers during molding An object of the present invention is to provide a pellet containing carbon fiber and a carbon fiber-containing pellet excellent in dispersibility of carbon fiber and a molding resin composition.

[0006]

To achieve the above object, the present invention is, firstly, to use a diene monomer and a monomer having an ethylenically unsaturated double bond as a monomer component, and have a glass transition point. Using a thermoplastic resin emulsion containing a diene-ethylene copolymer having a temperature of 20 ° C. or higher as a resin solid content, 30
A continuous carbon fiber bundle is immersed in the thermoplastic resin emulsion set to -80 ° C, and the continuous carbon fiber bundle to which the thermoplastic resin emulsion is attached is dried at a temperature of glass transition point to 300 ° C of the resin solid content. A carbon which is obtained by melting and adhering the resin solids to form a continuous carbon fiber bundle having 30% by weight or more of the resin solids attached on a dry basis, and cutting the continuous carbon fiber bundle into a predetermined length. A method for producing fiber-containing pellets is provided.

The first aspect of the present invention is that the temperature of the thermoplastic resin emulsion is set to 55 to 75 ° C., and the adhesion amount of the resin solids in the continuous carbon fiber bundle is 40% by weight on a dry basis. Over 70% by weight,
The diene monomer is one or more kinds of monomers selected from butadiene, isoprene, and chloroprene, and the diene-ethylene copolymer is 1 selected from styrene, acrylonitrile, and methyl methacrylate. One or more kinds of monomers and a diene-based monomer are copolymerized, and the diene-ethylene-based copolymer is a styrene-butadiene copolymer and / or acrylonitrile-
It is composed of a styrene-butadiene copolymer as a preferred embodiment.

In the second aspect of the present invention, in the manufacturing method according to the first aspect of the present invention, the continuous carbon fiber bundle to which the resin solid content is adhered has the same or different heat as the resin solid content. The present invention provides a process for producing carbon fiber-containing pellets, which comprises overcoating a plastic resin and then cutting the pellets into a predetermined length.

Further, the present invention thirdly provides a carbon fiber-containing pellet characterized by being produced by either the first or second production method of the present invention, and fourthly,
A third aspect of the present invention is to provide a molding resin composition, which is a blended product of the carbon fiber pellet and a thermoplastic resin which is the same as or different from the resin solid content.

[0010]

BEST MODE FOR CARRYING OUT THE INVENTION The production method of the present invention is a method for producing carbon fiber-containing pellets containing carbon fibers at a high concentration (first production method), and a carbon fiber content concentration higher than that of the first production method. Manufacturing method of carbon fiber-containing pellets that have been reduced to some extent (second
The manufacturing method) can be roughly divided into two modes. The carbon fiber-containing pellets obtained by the first production method usually constitute a molding resin composition as a blended product with a thermoplastic resin which serves as a matrix resin in a resin molded product. Also,
The carbon fiber-containing pellets obtained by the second production method constitute the molding resin composition alone or in the same manner as described above, as a blended product with a thermoplastic resin serving as a matrix resin in the resin molded product.

In the first production method of the present invention, a thermoplastic resin emulsion containing a specific resin solid content (hereinafter referred to as "emulsion") is added at a temperature of 30-80.
The continuous carbon fiber bundle (carbon fiber roving) is immersed at a temperature set to 0 ° C., the continuous carbon fiber bundle to which the emulsion is attached is dried, and the resin solids are melted and attached to form the continuous carbon with the resin solids attached. This is a method for producing carbon fiber-containing pellets by forming a fiber bundle and cutting this continuous carbon fiber bundle into a predetermined length. The second aspect of the present invention
The manufacturing method is a continuous carbon fiber bundle to which the resin solids are adhered by the same procedure as described above, and the same or different thermoplastic resin as the resin solids is overcoated and then cut into a predetermined length by containing carbon fibers. This is a method for producing pellets.

The continuous carbon fiber bundle used in the first and second production methods of the present invention is a bundle of carbon fiber monofilaments used in general carbon fiber reinforced resin, and the diameter of the carbon fiber is usually from several μm. The number of bundled carbon fiber monofilaments is about several tens of μm, and is about several thousand to several hundred thousand. Examples of the carbon fibers forming the continuous carbon fiber bundle include PAN-based, pitch-based, and rayon-based carbon fibers, which may be coated with a metal such as nickel or silver.

Usually, the continuous carbon fiber bundle is coated with a sizing agent called a sizing agent or a sizing agent in order to improve handleability as a bundle. As this sizing agent, for example, an epoxy resin or the like is used, and when handling carbon fibers as a bundle, it can be handled as a bundle without fluffing, and when dispersed in resin, it works so that each carbon fiber becomes disjointed Has become. The present invention has been made in consideration of the function of this sizing agent,
This point will be described later.

The emulsion used in the present invention contains, as a resin solid content, a diene-ethylene copolymer having at least a diene monomer and a monomer having an ethylenically unsaturated double bond as monomer components. .

The diene monomer is, for example, butadiene, isoprene, chloroprene, etc.
The ethylene-based copolymer can be obtained by emulsion-polymerizing the diene-based monomer and a monomer having an ethylenically unsaturated double bond with a known emulsifier to obtain a copolymer. . Examples of the monomer having an ethylenically unsaturated double bond include aromatic vinyl monomers such as styrene, α-methylstyrene and vinyltoluene; methacrylic acid,
Unsaturated carboxylic acids or unsaturated carboxylic acid esters such as allyl acid, itaconic acid, fumaric acid, maleic acid, itaconic acid monomethyl ester, maleic acid monomethyl ester; methyl methacrylate, 2-ethylhexyl acrylate, butyl acrylate, acrylic acid (Meta) such as ethyl
Acrylic ester; Cyanovinyl compound such as (meth) acrylonitrile; Vinyl compound containing hydroxyl group such as hydroxyethyl (meth) acrylate; Amide group-containing monomer such as (meth) acrylamide, N-methylol (meth) acrylamide; Glycidyl ( Examples thereof include (meth) acrylate.

The diene-ethylene copolymer contained as a resin solid content in the emulsion used in the present invention is required to have a glass transition point of 20 ° C. or higher. If the glass transition point is less than 20 ° C., the diene-based monomer is excessively large in terms of composition, so that the dispersibility of the carbon fiber is poor, and thermal discoloration may occur.
On the other hand, the upper limit of the glass transition point is not particularly limited as long as it is a diene-ethylene copolymer, but it is preferably 100 ° C or lower. Those having a glass transition point of higher than 100 ° C. have a reduced composition of diene monomers,
Good pelletization becomes difficult, and pills are likely to be formed during molding. Therefore, the diene-ethylene copolymer preferably has a glass transition point of 20 to 100 ° C. In other words, from the viewpoint of improving dispersibility of carbon fibers and preventing thermal discoloration, and at the same time, facilitating pelletization and preventing pill formation, a diene monomer and an ethylenically unsaturated double bond are used. When copolymerizing with a monomer having a bond, the amount of the diene-based monomer used is 2% by weight to 40% by weight based on the total amount of the monomers constituting the diene-ethylene-based copolymer. What can be obtained is preferable.

The emulsion used in the present invention may contain one kind of diene-ethylene-based copolymer or a plurality of kinds of diene-ethylene-based copolymer as the resin solid content. An emulsion containing either one or both of a butadiene-styrene copolymer and an acrylonitrile-styrene-butadiene copolymer as a resin solid content is preferable because good dispersibility of is easily obtained.

The glass transition point of the diene-styrene copolymer contained in the emulsion used in the present invention as a resin solid content is DSC when the diene-styrene copolymer contained is a single kind. The measured value. When the diene-styrene-based copolymer contained as the resin solid content is a mixture of a plurality of types of diene-styrene-based copolymers, the glass transition point is not 1 point, and therefore the total amount calculated by the following formula is The glass transition point Tg.
In the formulas below, Ta, Tb, Tc ... are the glass transition points of the components A, B, C ... contained, Ma, Mb, M, respectively.
c ... is the molar ratio of each component.

[0019]

[Equation 1]

The emulsion used in the present invention has a glass transition point of 20 ° C. or higher (preferably 20) in terms of cost and reduction in the number of steps in the total resin solids content.
It is preferably a diene-styrene-based copolymer of 100 to 100 ° C., but other resins can be contained in the range of 20% by weight or less, preferably 5% by weight or less based on the total resin components. For example, the dispersibility of carbon fibers can be improved by mixing and using a urethane emulsion within the above range with an emulsion containing the diene-styrene copolymer as a resin solid content.

An antioxidant, a heat stabilizer, a colorant and the like can be added to the emulsion used in the present invention, if necessary. In addition, the preferable amount of resin solids in the emulsion is 1 because it is easy to uniformly permeate into the inside of the continuous carbon fiber bundle and the required amount of adhesion is easily obtained.
It is in the range of 0% to 70% by weight.

In the present invention, the continuous carbon fiber bundle is immersed in an emulsion bath set at a temperature of 30 to 80 ° C., preferably 55 to 75 ° C., and the emulsion is impregnated and adhered to the carbon fibers. By setting the temperature of the emulsion to 30 to 80 ° C., preferably 55 to 75 ° C., the emulsion more uniformly coats the surface of each carbon fiber, increases the amount of the emulsion deposited, and when the emulsion is blended with the matrix resin. It is possible to improve the dispersion of the respective carbon fibers and increase the reinforcing effect of the carbon fibers.

To explain further, in the present invention, by setting the temperature of the emulsion to 30 ° C. or higher, it becomes easy for the emmansion to penetrate into the continuous carbon fiber bundle, and the surface of each carbon fiber is coated more uniformly. You can If it is lower than 30 ° C, its effect is low, while if it exceeds 80 ° C, the stability of the emulsion is lowered. This temperature is also closely related to the type of the above-mentioned sizing agent used for carbon fibers, and the viscosity of the epoxy resin or the like widely used as the sizing agent for carbon fibers is 30 to 80 ° C. It is presumed that the emulsion is made to easily enter between the carbon fibers. That is, the viscosity of a typical epoxy resin used as a sizing agent is 3000 poise at 20 ° C and 300 poise at 40 ° C.
Poise, 80 Poise at 50 ° C, 20 Poise at 70 ° C, 8
It is about 10 poise at 0 ° C., and when it exceeds 50 ° C., it is presumed that the viscosity is rapidly lowered and the penetration of the emulsion is facilitated.

The amount of the emulsion soaked in the emulsion and attached to the continuous carbon fiber bundle is based on the dry standard after the continuous carbon fiber bundle to which the emulsion is attached is subjected to the drying / melting treatment described later, and the continuous carbon fiber bundle. The amount is such that 30% by weight or more of resin solids remains attached. The upper limit is not particularly limited as long as it allows uniform adhesion, but is usually 100.
It is about% by weight. If this adhesion amount is less than 30% by weight,
When the obtained carbon fiber-containing pellets are melt-mixed with the thermoplastic resin used as the matrix resin, the dispersibility of the individual carbon fiber monofilaments in the matrix resin becomes insufficient. In order to obtain good dispersibility of the carbon fiber monofilament, it is preferable that the resin solid content in the emulsion infiltrate between the carbon fibers and each carbon fiber is covered with the resin solid content. In order to easily obtain the state, the adhesion amount of the emulsion in the continuous carbon fiber bundle is determined by the adhesion amount of the resin solids being 35 to 35 on a dry basis.
The amount is preferably 90% by weight, more preferably 40 to 70% by weight.

The continuous carbon fiber bundle is usually immersed in the emulsion by opening the continuous carbon fiber bundle and then allowing the continuous carbon fiber bundle to pass through an immersion tank containing the emulsion. At this time, it is only necessary to pass the continuous carbon fiber bundle opened into the emulsion, but a vibrator is installed in the immersion tank,
By vibrating the emulsion with this vibrating machine, the effect of permeating and coating the continuous carbon fiber bundle by immersion can be improved. Furthermore, the continuous carbon fiber bundle is usually opened at room temperature, but in addition to a heater that uses radiant heat such as heating wire, hot air, warm water, etc. are used to preheat and then open the emulsion. When it is passed through a dipping tank in which is added, the effect of permeating and coating the continuous fiber bundle can be improved.

The preferable passing speed of the continuous carbon fiber bundle in the immersion tank is 5 to 30 m / min. By passing through the immersion tank at this speed, the emulsion is uniformly attached to the opened continuous carbon fiber bundle. Various coatings can be formed.

The continuous carbon fiber bundle to which the emulsion is adhered by the immersion treatment in the immersion tank is dried by evaporating the water content of the emulsion adhered to the continuous carbon fiber bundle with a heating dryer equipped with a heater and the like. By melting and adhering the solid content, a film made of the resin solid content is formed. The heating / drying machine can be configured by a heater that uses radiant heat such as a heating wire or a heater that uses hot air.

The internal temperature of the heating dryer when passing the continuous carbon fiber bundle to which the emulsion is attached needs to be maintained within a range of 300 ° C. from the glass transition point of the resin solid content in the emulsion. The suitable temperature varies depending on the resin solid content used, but for example, a temperature of 100 ° C. to 300 ° C. for a budadiene-styrene copolymer and a temperature of 100 ° C. for an acrylonitrile-budadiene-styrene copolymer.
Drying / melting by heating in the range of 250 ° C. is desirable.

In the drying / melting process, the water in the adhered emulsion is evaporated and the resin solids contained in the emulsion are evenly adhered to the surface of each carbon fiber of the continuous carbon fiber bundle. Are uniformly melted and adhered and coated with the resin solid content. To ensure uniform adhesion by melting the resin solids, consider the melt viscosity and heat resistance of the resin solids when heating the continuous carbon fiber bundle to which the emulsion has adhered, and avoid exposing it to a high temperature atmosphere. Is preferred.

The thus dried and melted continuous carbon fiber bundle is cooled by air cooling or water cooling in the cooling section, and then it is adjusted to an appropriate length by a pelletizer arranged after the cooling section, for example, a length of about 3 to 20 mm. The carbon fiber-containing pellets can be obtained by cutting.

The production method of the carbon fiber-containing pellets of the present invention is as follows:
By using an emulsion containing a specific diene-ethylene copolymer having a diene monomer as one component as a resin solid content, and dipping a continuous carbon fiber bundle in the emulsion set to 30 to 80 ° C., The amount of emulsion impregnated into the continuous carbon fiber bundles has been greatly improved, and the surface of each carbon fiber monofilament forming the continuous carbon fiber bundles can be uniformly coated with a larger amount of resin solids, which has excellent elasticity. It is possible to obtain good quality carbon fiber-containing pellets. Further, the obtained carbon fiber-containing pellet has excellent dispersibility in various matrix resins without discoloration or fuzz of carbon fiber.

The carbon fiber-containing pellets of the present invention can be obtained by the first production method in which the continuous carbon fiber bundle coated with the resin solid content in the emulsion as described above is cooled and then cut. Since the carbon fiber-containing pellets of the present invention obtained by the first production method have a high carbon fiber concentration, they are usually another thermoplastic resin (matrix resin) which is the same as or different from the resin solid content contained in the emulsion. It is used for molding as a molding resin composition in which

The carbon fiber-containing pellets of the present invention are
In the same manner as above, a continuous carbon fiber bundle coated with the resin solid content in the emulsion was overcoated with a thermoplastic resin (matrix resin) which is the same as or different from the resin solid content, and after cooling, an appropriate length was obtained as described above. Second to cut into
It can also be obtained by the manufacturing method. Overcoating of the continuous carbon fiber bundle coated with the resin solid content in this emulsion can be performed using a normal molding machine such as an extrusion molding machine or an injection molding machine.

The carbon fiber-containing pellets of the present invention obtained by the second production method have no discoloration or fluffing of the carbon fibers and dispersibility in various matrix resins, like the carbon fiber-containing pellets produced by the first production method. In addition to being excellent, it can be made into a composite with a matrix resin in advance by overcoating, so that it can be used alone for molding. Further, similar to the carbon fiber-containing pellets produced by the first production method, a molding resin composition containing a thermoplastic resin which is the same as or different from the resin solid content contained in the emulsion can be used for molding.

The present invention will be described with reference to FIGS. 1 and 2. 1 and 2 each show a cross section of a carbon fiber-containing pellet obtained by an emulsion dipping method, but FIG. 1 shows the method of the present invention, that is, a diene monomer and an ethylenically unsaturated double bond. An emulsion containing a diene-ethylene-based copolymer having a glass transition point of 20 ° C. or higher obtained by copolymerization with a monomer having a bond as a resin solid content is used,
The continuous carbon fiber bundle was immersed in the emulsion bath set at 65 ° C., and the continuous carbon fiber bundle with the emulsion attached was dried at a temperature of the glass transition point of the resin solid content to 300 ° C.
A schematic diagram of a cross section of a carbon fiber-containing pellet produced by a melting process to cut a continuous carbon fiber bundle having a resin solid content adhered to the continuous carbon fiber bundle of 30% by weight or more into a predetermined length, Figure 2 shows the temperature of the emulsion bath at 25
It is a schematic diagram of a cross section of a carbon fiber-containing pellet that is similarly prepared by setting the temperature to ° C.

As is apparent from FIGS. 1 and 2, in FIG. 1 in which the temperature of the emulsion bath is 65 ° C., the surface of each carbon fiber monofilament 1 is uniformly coated with the resin solid content 2 remaining on the carbon fiber monofilament 1 The fiber monofilament 1 is uniformly dispersed by the resin solid content 2 remaining attached. On the other hand, in FIG. 2, the carbon fiber monofilaments 1 are partially aggregated and fixed, and
And the solid state of the resin solid content 2 is not uniform. When these carbon fiber-containing pellets and a thermoplastic resin as a matrix resin are melt-mixed and blended and used for injection molding, when the carbon fiber-containing pellets of FIG. 1 are used, the carbon fiber-containing pellets of FIG. 2 are used. Compared with the case where pellets are used, the carbon fibers are more uniformly dispersed, the reinforcing effect of the carbon fibers is significantly exhibited, and a higher quality fiber-reinforced resin molded product can be obtained.

[0037]

EXAMPLES The present invention will be described more specifically below with reference to examples and comparative examples. In the examples and comparative examples, “%” is based on weight.

In the following Examples and Comparative Examples, the apparatus for molding and evaluation, the materials used, etc. are as follows.

<Device for molding and evaluation> Injection molding machine: "IS55EPN" manufactured by Toshiba Machine Co., Ltd. Tumble mixer: "MT-5" manufactured by Matsui Manufacturing Co., Ltd.
0 ”.

<Matrix resin> PS: “Styron <registered trademark> 68 manufactured by Asahi Kasei Corporation
0 ”. AS: "Styrac <registered trademark> AS manufactured by Asahi Kasei Corporation
783 ". ABS: "Styrac <registered trademark> A manufactured by Asahi Kasei Corporation
BS121 ". PPE: Asahi Kasei's "Zylon <registered trademark>100"
Z ". PC: "Novarex 7022A" manufactured by Mitsubishi Engineering Plus Plastic Co., Ltd.

<Emulsion> SB-1: Styrene (ST) -butadiene (BD) copolymer emulsion (ST = 99%, BD = 1%). SB-2: Styrene (ST) -butadiene (BD) copolymer emulsion (ST = 80%, BD = 20%). ABSLa: Acrylonitrile (AN) -Styrene (S
T) -butadiene (BD) copolymer emulsion (AN
= 25%, ST = 60%, BD = 15%).

<Carbon fiber> Carbon fiber roving (CF-R): Toho Rayon Co., Ltd.
"HTA-W12K" manufactured, the carbon fiber bundle is composed of 12,000 carbon fiber monofilaments, and the diameter of the carbon fiber monofilaments is 7 μm.

<Measurement of Carbon Fiber Dispersion> Using the carbon fiber-containing pellets prepared in Examples and Comparative Examples and various matrix resins, the thermoplastic resin that needs to be dried is dried so that the carbon fiber concentration becomes 10% by weight. The mixture was weighed and mixed into a plate, and a plate (width 30 mm x length 200 mm x thickness 2.5 mm) was molded using an injection molding machine under normal molding conditions and a molding cycle. Was evaluated according to the standard. In addition, the carbon fiber-containing pellets prepared in Examples and Comparative Examples had a carbon fiber content of 10
Matrix resin overcoated so as to have a weight% was formed into a plate (width 30 mm x length 2 according to normal molding conditions and molding cycle using an injection molding machine.
(00 mm × thickness 2.5 mm) was molded, and the dispersion state of carbon fibers on the plate surface was observed and evaluated according to the following criteria.

◯: There is no lump of carbon fiber (carbon fiber aggregate) over the entire length, and the carbon fiber is well dispersed. Δ: Some carbon fiber lumps (carbon fiber aggregates) are seen.

Examples 1 to 7, Comparative Examples 1 and 2 The CF-R to which the resin solid content in the emulsion was attached was 5 mm under the types of emulsion shown in Table 1, immersion conditions in the emulsion, and drying / melting conditions. Cut with a cutter consisting of a rotary blade to make carbon fiber-containing pellets of length,
The carbon fiber-containing pellets of Examples 1 to 6 and Comparative Examples 1 and 2 were obtained.

The carbon fiber-containing pellets thus obtained were blended with each matrix resin shown in Table 1 so that the carbon fiber content in the total resin was 10% by weight, and injection molding was carried out. In the molding resin composition containing the carbon fiber-containing pellets shown in Examples 1 to 7, the carbon fibers were uniformly mixed up to the fluidized end of the molded product, and the carbon fiber dispersity was ◯. On the other hand, in the molding resin composition containing the carbon fiber-containing pellets shown in Comparative Examples 1 and 2, it was observed that the carbon fibers were mixed nonuniformly, and the dispersity was Δ.

Examples 8-10, Comparative Examples 3 and 4 Carbon was added to CF-R to which the resin solid content in the emulsion was adhered under the types of emulsion shown in Table 1, immersion conditions in the emulsion, and drying / melting conditions. Fiber content is 10% by weight
As shown in Table 1, the matrix resins shown in Table 1 were overcoated and then cut with a cutter composed of a rotary blade to form carbon fiber-containing pellets having a length of 5 mm. Examples 8 to 10 and Comparative Examples 3 and 4 Carbon fiber-containing pellets were obtained.

When the obtained carbon fiber-containing pellets were used alone for injection molding, the carbon fiber-containing pellets shown in Examples 8 to 10 were such that the carbon fibers were uniformly distributed in the molded product. The dispersity of was 0. On the other hand, in the carbon fiber-containing pellets shown in Comparative Examples 3 and 4, some carbon fiber lumps were found in the molded product, and the dispersity was Δ.

[0049]

[Table 1]

[0050]

The present invention is as described above, and it is possible to obtain a carbon fiber-containing pellet having excellent carbon fiber dispersibility. Further, according to the carbon fiber pellets obtained by the production method of the present invention and the molding resin composition in which the matrix resin is mixed, a resin molded article in which carbon fibers are uniformly dispersed and which has a high reinforcing effect by the carbon fibers is obtained. Is something that can be done.

[Brief description of drawings]

FIG. 1 is a schematic view of a cross section of a carbon fiber-containing pellet according to the manufacturing method of the present invention.

FIG. 2 is a schematic view of a cross section of a carbon fiber-containing pellet produced by a conventional method.

[Explanation of symbols]

1 carbon fiber monofilament 2 resin solids

─────────────────────────────────────────────────── ─── Continuation of front page (51) Int.Cl. ⁷ Identification code FI theme code (reference) // B29K 9:00 B29K 9:00 105: 08 105: 08 (72) Inventor Tadahiro Shimada Yokaichi City, Shiga Prefecture Kaminedacho 1138 F term (reference) 4F070 AA06 AA07 AA08 AC04 AD02 AE01 BA02 BB08 DA33 DA55 4F201 AA46 AB11 AC05 AD16 BA02 BC19 BC33 BL06 BL44 4J002 AC021 AC071 AC081 BN151 DA016 FA046

Claims (9)

[Claims] 1. A diene-based monomer and a monomer having an ethylenically unsaturated double bond as monomer components, and a diene-ethylene-based copolymer having a glass transition point of 20 ° C. or higher as a resin solid content. 30 using a thermoplastic resin emulsion
A continuous carbon fiber bundle is immersed in the thermoplastic resin emulsion set to -80 ° C, and the continuous carbon fiber bundle to which the thermoplastic resin emulsion is attached is dried at a temperature of glass transition point to 300 ° C of the resin solid content. A carbon which is obtained by melting and adhering the resin solids to form a continuous carbon fiber bundle having 30% by weight or more of the resin solids attached on a dry basis, and cutting the continuous carbon fiber bundle into a predetermined length. Manufacturing method of fiber-containing pellets. 2. The method for producing carbon fiber-containing pellets according to claim 1, wherein the temperature of the thermoplastic resin emulsion is set to 55 to 75 ° C. 3. The carbon fiber-containing material according to claim 1, wherein the amount of the resin solids deposited on the continuous carbon fiber bundle is more than 40% by weight and 70% by weight or less on a dry basis. How to make pellets. 4. The carbon fiber-containing pellet according to claim 1, wherein the diene monomer is one or more kinds of monomers selected from butadiene, isoprene and chloroprene. Manufacturing method. 5. The diene-ethylene copolymer is a copolymer of a diene monomer and one or more monomers selected from styrene, acrylonitrile, and methyl methacrylate. Claims 1, 2, characterized in that
The method for producing a carbon fiber-containing pellet according to 3 or 4. 6. The carbon fiber-containing pellet according to claim 5, wherein the diene-ethylene copolymer comprises a styrene-butadiene copolymer and / or an acrylonitrile-styrene-butadiene copolymer. Manufacturing method. 7. The continuous carbon fiber bundle to which the resin solid content is adhered is overcoated with a thermoplastic resin which is the same as or different from the resin solid content, and then cut into a predetermined length. The method for producing a carbon fiber-containing pellet according to 1, 2, 3, 4, 5 or 6. 8. A carbon fiber-containing pellet produced by the method of claim 1, 2, 3, 4, 5, 6 or 7. 9. A molding resin composition, which is a blend of the carbon fiber-containing pellet according to claim 8 and a thermoplastic resin which is the same as or different from the resin solid content.