JP2013119685A - Opened carbon fiber bundle and method for producing the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an opened carbon fiber bundle and a method for producing the same, and a carbon fiber product obtained from the opened carbon fiber bundle.SOLUTION: The method for producing the opened carbon fiber bundle comprises: applying a dispersion liquid that contains a surface active agent and comprises a sizing agent and water, to a carbon fiber bundle; drying the carbon fiber bundle so that a content of water becomes 1-20 pts.wt. with respect to 100 pts.wt. of a carbon fiber; and then subjecting the carbon fiber bundle to an opening process.

Description

  The present invention relates to an opened carbon fiber bundle, a method for producing the same, and a carbon fiber product obtained from the opened carbon fiber bundle.

Carbon fiber is a material that has been widely applied as a composite material with a resin in order to increase the strength of the resin and at the same time, the resin can buffer the brittle fracture of the carbon fiber.
On the other hand, since carbon fiber is composed of a large number of ultrafine filaments, the elongation is small and fluff is likely to occur due to mechanical friction or the like. In order to improve this problem, a sizing agent is added to the carbon fiber for the purpose of improving the adhesion with the matrix resin at the time of compounding with the resin and improving the convergence and handling of the carbon fiber. Is common.

Resins used for compounding with carbon fibers include thermosetting resins and thermoplastic resins.
For example, Patent Document 1 proposes a sizing agent containing bisphenol A type epoxy resin that is liquid at room temperature, bisphenol A type epoxy resin that is solid at room temperature, unsaturated polyester resin, and stearic acid as essential components.
Further, for example, Patent Document 2 proposes using a modified and emulsified thermoplastic resin similar to the resin to be combined as a sizing agent used at the interface between the carbon fiber surface and the thermoplastic resin. .
However, the carbon fiber bundle obtained in the above-mentioned patent document is imparted to the carbon fiber with a polymer that is polymerized to some extent, so that the texture becomes hard near the room temperature generally used, and the openability is reduced. There was a problem.

  As a method for solving this problem, for example, Patent Document 3 discloses that a sizing agent containing a surfactant as a main component is applied to the surface of the carbon fiber to improve the openability of the carbon fiber bundle in water. It is disclosed. However, in the carbon fiber bundle obtained by this method, the range of heat treatment conditions in the sizing process is narrow due to volatilization of the surfactant and the production management is difficult. Furthermore, since it is premised on opening in water, the applicable processes are limited.

JP-A-7-197381 JP-A-6-107442 WO06 / 018139

  An object of this invention is to provide the carbon fiber bundle which was excellent in the handleability and improved the opening property.

The present invention provides a dispersion comprising a sizing agent containing a surfactant and water to carbon fiber, and the water content is 1 to 20 parts by weight with respect to 100 parts by weight of carbon fiber. This is a method for producing an opened carbon fiber bundle, which is subjected to an opening process.
According to the present invention, the adhesion amount of the sizing agent in the opened carbon fiber bundle can be 0.01 to 10 parts by weight with respect to 100 parts by weight of the carbon fibers.

  According to the present invention, it is possible to obtain a carbon fiber bundle excellent in handleability and improved fiber opening property and a carbon fiber product therefrom. Handleability means that troubles such as tangling are reduced in the process of specifically cutting the fiber and the process of opening the fiber bundle, and improving the spreadability means the process of opening the fiber. By providing, the carbon fiber bundle state suitable for the form of the desired carbon fiber product can be made.

Schematic explanatory drawing of a taper pipe. Explanatory drawing of the tensile shear strength measuring method.

  The present invention provides a drying step in which a dispersion comprising a sizing agent containing a surfactant and water is applied to the carbon fiber bundle, and the water content is 1 to 20 parts by weight with respect to 100 parts by weight of the carbon fiber. Then, it is the opened carbon fiber bundle obtained by this manufacturing method, and the manufacturing method of the opened carbon fiber bundle which uses it for an opening process.

  The opening rate of the opened carbon fiber bundle in the present invention is, for example, that the carbon fiber bundle is cut to 20 mm, the carbon fiber inlet diameter is 20 mm, the outlet diameter is 55 mm, and the length of the pipe is blown from the inlet. Introduced into a tapered tube having a diameter of 400 mm up to the mouth, and a width of less than 0.6 mm existing in the entire fiber after being blown by flowing compressed air so that the compressed air pressure introduced into the Taber tube is 0.25 MPa It can be evaluated by the weight ratio of the fiber bundle. Thus, when the fiber opening rate is defined, the opened carbon fiber bundle of the present invention preferably has a fiber opening rate of 40% or more. The opening rate can be appropriately selected depending on the carbon fiber product to be obtained, but is preferably 45 to 90%, and more preferably 45 to 80%. Hereinafter, embodiments of the present invention will be sequentially described.

<Carbon fiber>
Any carbon fiber such as polyacrylonitrile (PAN), petroleum / coal pitch, rayon, and lignin can be used for the carbon fiber bundle in the present invention. In particular, PAN-based carbon fibers using PAN as a raw material are preferable because they are excellent in productivity and mechanical properties on an industrial scale.
It is preferable to use carbon fibers having an average diameter of 5 to 10 μm. Moreover, it is preferable to use a fiber bundle of 1000 to 50000 short fibers. In order to enhance the adhesion between the carbon fiber and the matrix resin, it is also preferable to use a material in which an oxygen-containing functional group is introduced on the surface of the carbon fiber by a surface treatment.

<Sizing agent>
The sizing agent in the present invention is not particularly limited, and a sizing agent that is compatible with the resin to be combined may be selected in consideration of each case. Specific examples of the sizing agent suitably used in the present invention include epoxy resin, urethane resin, vinyl chloride resin, vinylidene chloride resin, vinyl acetate resin, polyvinyl alcohol resin, polystyrene resin, acrylonitrile-styrene resin (AS resin). , Acrylonitrile-butadiene-styrene resin (ABS resin), acrylic resin, methacrylic resin, polyolefin resin, polyamide resin, polyacetal resin, polycarbonate resin, polyethylene terephthalate resin, polyethylene naphthalate resin, boribylene terephthalate resin, polyarylate resin, polyphenylene ether Resin, polyphenylene sulfide resin, polysulfone resin, polyethersulfone resin, polyetheretherketone resin, polylactic acid resin, polyimide resin , And polyvinylpyrrolidone. Two or more copolymers or modified products of those shown above may be used as a mixture. The present invention can be applied when the above-described materials can be obtained as a general dispersion in water. Preferably, a polyolefin resin or a polyamide resin is used as a main component. By using polyolefin resin or polyamide resin, for example, the former has high compatibility with polyolefin resins such as polypropylene, and the latter has high adhesiveness with respect to highly polar resins, particularly polyamide resins. It is done.

<Surfactant>
The surfactant used in the present invention is not particularly limited as long as a dispersion composed of a sizing agent and water can be prepared. Specific examples include nonionic surfactants, anionic surfactants, cationic surfactants, and amphoteric surfactants. Among these, it is preferable to use a nonionic surfactant or an anionic surfactant from the viewpoint of the particle diameter of the dispersed particles, and a nonionic surfactant is more preferable. Preferable specific examples of the nonionic surfactant include polyoxyalkylene alkyl ethers represented by the following formula (1).
^{_{H 2m2 + 1 C m2 -O- (}} X 2 -O) n2 -H (1)
(M2 = integer of 8 to 22, n2 = integer of 2 to 20, X ² : alkylene group having 1 to 5 carbon atoms)

The number of carbon atoms of the alkylene group represented by X2 is preferably 2 to 5, and examples of the polyoxyethylene alkyl ether include polyoxyethylene lauryl ether, polyoxyethylene cetyl ether, polyoxyethylene oilel ether and the like. These compounds can be used individually by 1 type or in mixture of 2 or more types.
In the present invention, the surfactant only needs to be able to obtain an aqueous dispersion of the resin constituting the sizing agent, and it is preferable to keep the amount of the surfactant used as low as possible. It is preferable that a sizing agent contains 0.01-8 weight part of surfactant with respect to 100 weight part of resin solid content.

<Dispersion liquid consisting of sizing agent and water>
There is no particular limitation on the amount ratio of the dispersion composed of the sizing agent and water, as long as a uniform dispersion can be obtained. As a preferable quantitative ratio, the solid content (pure content) of the sizing agent is from 900 parts by weight of water to 999,900 parts by weight of water, that is, 100 parts by weight of the sizing agent, with respect to 100 parts by weight of the solid content (pure content) of the sizing agent. ) 0.01 to 10 parts by weight is preferred. More preferably, the solid content (pure content) of the sizing agent is 0 to 1900 parts by weight of water, that is, 100 parts by weight of the sizing agent, based on 100 parts by weight of the solid content (pure content) of the sizing agent. 0.1 to 5 parts by weight. These are preferably used after being well stirred.

<Immersion process>
There is no particular limitation on the method of applying a dispersion composed of a sizing agent containing a surfactant and water to the carbon fiber, and any conventionally known method may be used as long as the sizing agent can be uniformly applied to the surface of the carbon fiber bundle. be able to. Specific methods include, for example, a spray method, a roller dipping method, a roller transfer method, and the like, including a method of using these alone or in combination. Among these sizing methods, the roller dipping method is preferable as a method excellent in productivity and uniformity. When dipping a carbon fiber strand in an aqueous emulsion or solution, it is important to repeat the opening and squeezing through an immersion roller provided in the emulsion bath, and to impregnate the aqueous emulsion or solution into the strand. is there. The amount of the sizing agent attached to the carbon fiber can be adjusted by adjusting the concentration of the sizing agent for carbon fiber, adjusting the squeeze roller, or the like.

<Drying process>
One of the features of the method of the present invention is that it is subjected to a fiber-opening step after a drying step in which the water content is controlled within a certain range.
A certain amount of water is removed from the carbon fiber bundle to which the above dispersion is applied by a drying treatment. In this case, the method for the drying treatment is not particularly limited, and examples thereof include heat treatment, air drying, and centrifugal separation. Among them, heat treatment is preferable. By using a heat treatment as the drying treatment, in addition to removing moisture from the carbon fiber bundle after the sizing treatment, the sizing agent can be uniformly dispersed on the surface of the carbon fiber. As a heating means for the heat treatment, for example, hot air, a hot plate, a roller, an infrared heater or the like can be used. When the drying treatment is performed by heat treatment, the heat treatment temperature and the heat treatment time are controlled in order to keep the moisture content of the obtained carbon fiber bundle within a desired range. When the carbon fiber sizing agent is applied in an aqueous emulsion, it is preferable to remove moisture at a material temperature of about 80 ° C to 150 ° C. If it is this temperature range, the target carbon fiber bundle can be obtained, without degrading resin of a sizing agent and by extension, a carbon fiber bundle.

In addition, a certain amount of water can be maintained by further applying water to the carbon fiber bundle that has undergone the drying process using a spray or the like, or storing it in an environment in which moisture does not evaporate. Storage in an environment where moisture does not evaporate may be, for example, storage in a humidity chamber or storage in a refrigerator.
The content of water in the carbon fiber subjected to the opening process through the drying process is 1 to 20 parts by weight with respect to 100 parts by weight of the carbon fiber. If the upper limit of the amount of moisture is 20 parts by weight or less, the handleability of the carbon fiber is not impaired. A suitable upper limit is 15 parts by weight with respect to 100 parts by weight of the carbon fiber bundle. Moreover, the lower limit of the content of water is 1 part by weight, and if it is less than this, the effect of the spreadability due to the application of water is not fully utilized. A preferred lower limit is 5 parts by weight. Here, in the present invention, the amount of water in the carbon fiber bundle refers to the weight of water relative to the carbon fiber and the weight of the sizing agent adhering to the carbon fiber.

<Opening process>
The fiber bundle which passed through said drying process is used for a fiber opening process. The method of opening the carbon fiber bundle is not particularly limited, but preferably, a method of squeezing the fiber with a round bar, a method of using an air flow, a method of vibrating the fiber with ultrasonic waves, and the like are mentioned. In the method of opening the fiber bundle by blowing air onto the carbon fiber bundle, the degree of opening can be appropriately controlled by the pressure of the air or the like. The fibers subjected to these opening processes may be continuous fibers or discontinuous fibers.

<Obtained carbon fiber products>
A carbon fiber bundle opened by the method of the present invention is obtained, and a carbon fiber product is obtained by processing the bundle. In the obtained carbon fiber product, the amount of the sizing agent is preferably 0.01 to 10 parts by weight with respect to 100 parts by weight of the carbon fiber. That is, in the method for producing a carbon fiber bundle of the present invention, it is preferable to apply the dispersion so that 0.01 to 10 parts by weight of the sizing agent adheres to 100 parts by weight of the carbon fiber bundle. The carbon fiber product obtained by the method of the present invention preferably has a surfactant content of 0.01 to 8 parts by weight with respect to 100 parts by weight of the resin solid content in the sizing agent. More preferably, it is preferable that the amount of the surfactant is as small as possible when the aqueous dispersion of the resin is produced.

  The method for producing a carbon fiber product of the present invention is a carbon fiber bundle to which a sizing agent is applied, and the amount of water in the carbon fiber bundle is 1 to 20 parts by weight with respect to 100 parts by weight of the carbon fiber bundle. At least the step of opening the fiber bundle is performed. A sufficiently opened carbon fiber can be easily obtained by opening a carbon fiber bundle containing a specific amount of moisture.

The carbon fiber product obtained by using the carbon fiber bundle of the present invention is sufficiently high in impregnation with a matrix resin to be combined and has little unevenness in strength. Examples of such carbon fiber products include a random mat, a uniaxially oriented carbon fiber composite material, and a woven fabric that will be described in detail later.
The carbon fiber product may contain various additives as long as the object of the present invention is not impaired. Examples of the additive include a surfactant. Moreover, as a thing contained other than the opened carbon fiber bundle, a carbon fiber single yarn and one or more types of thermoplastic resins are mentioned.

<Random mat>
The random mat refers to a fiber in which reinforcing fibers are not oriented in a specific direction and are dispersed in a random direction within the plane of the random mat. Further, the average fiber length of the reinforcing fibers in the random mat is 5 to 100 mm or less, preferably 10 to 100 mm, more preferably 15 mm or more and 100 mm or less, and further preferably 15 mm or more and 80 mm or less. Furthermore, 20 mm or more and 60 mm or less are preferable, and one of these fiber lengths or a combination of two or more may be formed.
In the present invention, the random mat is composed of a carbon fiber bundle having a fiber length of 2 to 60 mm and a thermoplastic resin, and the carbon fiber is substantially in-plane random with a basis weight of 25 to 3000 g / m ^2. It is characterized by being oriented.

  In the present invention, the thermoplastic resin used is not particularly limited, but is preferably a polypropylene resin or a polyamide resin. In addition to the propylene unit, the copolymer component includes ethylene, α-olefins other than propylene, cyclic olefins, unsaturated acids and derivatives thereof, unsaturated acids and acid anhydrides, and the like. Examples of the α-olefin include 1-butene, 1-pentene, 1-hexene, 1-heptene, 1-octene, 1-nonene, 1-decene, 4-methyl-1-pentene, and the like. it can. Cyclic olefin monomers include cyclobutene, cyclopentene, cyclopentadiene, 4-methylcyclopentene, 4,4-dimethylcyclopentene, cyclohexene, 4-methylcyclohexene, 4,4-dimethylcyclohexene, 1,3-dimethylcyclohexene, 1,3. -Cyclohexadiene, 1,4-cyclohexadiene, cycloheptene, 1,3-cycloheptadiene, 1,3,5-cycloheptatriene, cyclooctene, 1,5-cyclooctadiene, cyclododecene and the like can be mentioned. Examples of the unsaturated acid include maleic acid, fumaric acid, acrylic acid, methacrylic acid, and examples of the unsaturated acid anhydride include maleic anhydride. These copolymers can take the structure of a random copolymer, a block copolymer, and a graft copolymer. A preferable copolymer molar ratio when it contains a copolymer component is 0.1 to 50%. The polypropylene resin can be used in combination with other resins. Such resins include ethylene-propylene copolymer elastomer (EPR), ethylene-propylene-diene copolymer elastomer (EPDM), ethylene-butene-1 copolymer elastomer (EBM), ultra-low density polyethylene, styrene- Examples thereof include butadiene block copolymer elastomers, styrene-butadiene random copolymer elastomers, and styrene-isoprene block copolymer elastomers.

Specific examples of the polyamide-based resin include — [NH (CH ₂ ) ₅ CO] —, — [NH (CH ₂ ) ₆ NHCO (CH ₂ ) ₄ CO] —, — [NH (CH ₂ ) ₆ NHCO (CH _{2) 8 CO] -, -} [NH (CH 2) 10 CO] -, - [NH (CH 2) 11 CO] -, and _{- [NH (CH 2) 2} NHCO-D-CO] - ( wherein A polyamide resin having a structural unit of at least one selected from the group consisting of D represents an unsaturated hydrocarbon having 34 carbon atoms is preferably used. Specific examples thereof include 6-nylon, 66-nylon, 610-nylon, 11-nylon, 12-nylon, 6/66 copolymer nylon, 6/610 copolymer nylon, 6/11 copolymer nylon, 6/12. Copolymer nylon, 6/66/11 copolymer nylon, 6/66/12 copolymer nylon, 6/66/11/12 copolymer nylon, 6/66/610/11/12 copolymer nylon and dimer acid polyamide Examples thereof include resins. These polymers or copolymers may be used alone or as a mixture of two or more.

  Moreover, an inorganic filler can be mix | blended with said resin. Examples of the inorganic filler include talc, calcium silicate, calcium silicate, wollastonite, montmorillonite, and various inorganic nanofillers. In addition, the above resins include heat stabilizers, antistatic agents, weather stabilizers, light stabilizers, anti-aging agents, antioxidants, softeners, dispersants, fillers, colorants, lubricants, etc. Other additives conventionally blended in polyolefin compositions can be blended.

The amount of the thermoplastic resin present in the random mat is preferably 10 to 500 parts by weight with respect to 100 parts by weight of the carbon fibers. More preferably, it is 20-400 weight part.
In the random mat, the thermoplastic resin is preferably present in the form of fibers, powders, or granules.

The random mat is 1. A step of cutting the carbon fiber bundle,
2. A process of opening the fiber bundle by introducing cut carbon fiber into the tube and blowing air on the fiber;
3. An application process in which the carbon fiber and the thermoplastic resin are simultaneously sprayed while spreading the spread carbon fiber and sucking it together with the thermoplastic resin.
4). Fixing the applied carbon fiber and thermoplastic resin;
More preferably.

  The degree of opening of the carbon fibers in the thermoplastic resin matrix is controlled, and a random mat containing a specific number of carbon fibers bundles other than the number of carbon fibers bundled in a specific ratio may be used. preferable. According to the production method of the present invention, it is possible to appropriately control the spread rate, and it is possible to provide a random mat suitable for various uses and purposes.

For example, a carbon fiber bundle is cut into 20 mm, introduced into a taper tube having a carbon fiber inlet diameter of 20 mm, an outlet diameter of 55 mm, and a pipe length of 400 mm from the inlet to the outlet. A random mat can be obtained by spraying by flowing compressed air so that the compressed air pressure is 0.25 MPa. The weight ratio of the fiber bundle having a width of less than 0.6 mm present in the entire fiber at this time is defined as the fiber opening rate.
By producing a random mat with an appropriate spread rate, it becomes possible to achieve a higher physical property by closely adhering the carbon fiber and the thermoplastic resin.

<Uniaxially oriented carbon fiber composite material>
By aligning the opened carbon fiber bundles of the present invention and bringing them into contact with a molten thermoplastic resin, a uniaxially oriented carbon fiber composite material in which the carbon fiber bundle and the thermoplastic resin are combined can be obtained. The thermoplastic resin used at this time is preferably a polypropylene resin or a polyamide resin. The uniaxially oriented carbon fiber composite material may be formed by laminating a plurality of uniaxially oriented carbon fiber composite materials.
As the polypropylene resin and the polyamide resin, those described in the above-mentioned random mat are preferably mentioned.

  The method for producing the uniaxially oriented carbon fiber composite material layer is not particularly limited, and can be obtained, for example, by a pultrusion method. In the case of the pultrusion method, a carbon fiber impregnated with a thermoplastic resin is preferably obtained. When a layer impregnated with a thermoplastic resin is suppressed, that is, a semi-impregnated layer, for example, a method of aligning carbon fibers in one direction on a sheet made of a thermoplastic resin and heating while pressing if necessary is preferable. Can be obtained.

  The shape of the composite material is preferably cylindrical or prismatic. A long fiber pellet made of carbon fiber and a thermoplastic resin can be obtained by obtaining a strand obtained by solidifying a carbon fiber bundle with a thermoplastic resin and cutting the strand. In the case of a prismatic shape, a sheet shape can be obtained by reducing the height (thickness). A preferable thickness when the sheet is formed is 40 to 3000 μm. The amount of the thermoplastic resin in the uniaxially oriented carbon fiber composite material is preferably 10 to 500 parts by weight with respect to 100 parts by weight of the carbon fibers. More preferably, it is 20-250 weight part.

  Examples are shown below, but the present invention is not limited thereto. The examples of the present invention were evaluated by the following methods.

<Method for measuring water content in carbon fiber bundle>
The amount of water in the carbon fiber bundle was measured by weighing two obtained carbon fiber bundles at 1.0 m, weighing them thoroughly with a dryer at 105 ° C., and weighing again. It is the average of those calculated by equation (2).
Water content = (ab) / b × 100 (%) (2)
a: Carbon fiber bundle weight before drying [g]
b: Weight of carbon fiber bundle after drying [g]

<Measurement method of amount of sizing agent attached to carbon fiber bundle>
The amount of sizing agent deposited was taken from two 1.0 m carbon fiber bundles that had been sized and fired in a furnace heated to 500 ° C. for 10 minutes. As an average of those calculated by the following equation (3).
Sizing agent adhesion amount = (ab) / b × 100 (%) (3)
a: Weight of carbon fiber bundle before firing [g]
b: Weight of carbon fiber bundle after firing treatment [g]

<Evaluation test for opening of carbon fiber bundle>
The carbon fiber bundle was cut into a length of about 20 mm using a rotary cutter. As shown in FIG. 1, the cut fiber bundle has a carbon fiber inlet diameter of 20 mm, an outlet diameter of 55 mm, a pipe length of 400 mm from the inlet to the outlet, and several 1 mm holes in the pipe. Using an optical microscope, the width of the carbon fiber bundle was introduced into an open trumpet-shaped taper tube and sprayed by flowing compressed air so that the compressed air pressure before the Taber tube was 0.25 MPa. Measured and classified as follows.
a: Less than 0.6 mm b: 0.6 mm or more
This classification was performed, the weight of the bundle belonging to the group a and the weight of the bundle belonging to the group b were measured, and the fiber opening rate was calculated using the following formula (4).
Opening rate x = a / (a + b) × 100 (%) (4)
Here, it can be said that the larger the x, the higher the fiber opening rate.

<Method of measuring tensile shear strength using carbon fiber bundle>
Two carbon fiber bundles having a predetermined length are prepared from the sized carbon fiber bundles, and a polypropylene film (a propylene film manufactured by Tosello Co., CPS # 50) is bonded to the polypropylene between the two bundles. The polyamide film (Unitika emblem, 30 μm) is bonded to the polyamide at a temperature of 230 ° C. for 2 minutes and 30 seconds and a temperature of 260 ° C. for 2 minutes and 30 seconds with an adhesive portion length of 3 mm. The predetermined length is the length of the bonded portion + 50 mm, 57 mm for polypropylene and 53 mm for polyamide.
Anti-slip processing is performed by sandwiching each of two pieces of sandpaper with a roughness of # 320 at both ends of a test piece made of this fiber bundle (FIG. 2). Using this sample as the final test piece, a tensile shear strength measurement according to JIS K6850 was applied using an autograph (Shimadzu Corporation, AGS-X 5kN) at a test speed of 3 mm / min. Was measured. Seven of the samples were measured, and the average value was taken as the tensile shear strength.

<Measurement method of bending properties of carbon fiber random mat composite molding plate>
A test piece having a width of 15 mm and a length of 100 mm was cut out from the molded plate and evaluated by three-point bending with a central load in accordance with JIS K7074. Maximum load and center deflection when a test piece is placed on a fulcrum of r = 2mm with a fulcrum distance of 80mm and a load is applied at a test speed of 5mm / min with an indenter of r = 5mm in the center between the fulcrum The bending strength and the bending elastic modulus were measured.

[Example 1]
280 parts by weight of propylene / styrene copolymer (molar ratio of styrene to propylene 100), 25 parts by weight of maleic anhydride, 7 parts by weight of dicumyl peroxide and 420 parts by weight of toluene were placed in an autoclave equipped with a stirrer. In addition, nitrogen substitution was performed for about 5 minutes, and then the reaction was performed at 140 ° C. for 5 hours with heating and stirring. After completion of the reaction, the reaction solution was put into a large amount of methyl ethyl ketone to precipitate a crude copolymer polyolefin. The crude copolymerized polyolefin was further washed several times with methyl ethyl ketone to remove unreacted maleic anhydride, and then dried under reduced pressure to obtain a copolymerized polyolefin solid. From the measurement result of the infrared absorption spectrum, the copolymerization ratio of maleic anhydride was 0.7 with respect to propylene 100 in molar ratio. Moreover, the weight average molecular weight by high temperature GPC measurement was 86000.

  Next, 400 parts by weight of toluene was added to 100 parts by weight of the copolymerized polyolefin, and the mixture was heated with stirring to be uniformly dissolved. On the other hand, 8 parts by weight of a polyoxyethylene alkyl ether surfactant (manufactured by Kao Corporation, polyoxyethylene lauryl ether registered trademark “Emulgen 103”) was added to 400 parts by weight of water and dissolved in another container. A toluene solution of copolymerized polyolefin and an aqueous surfactant solution were placed in an emulsifier and stirred to obtain a pre-emulsion. Morpholine was added to this pre-emulsion, the temperature of the pre-emulsion was maintained at 45 ° C., and toluene in the system was distilled under reduced pressure at 100 to 200 Torr using a rotary evaporator.

The finally obtained copolymer polyolefin aqueous emulsion had an average particle diameter of 0.7 μm, and water was 400 parts by weight with respect to 100 parts by weight of polyolefin.
The sizing agent emulsion was stirred so that the copolymerized polyolefin was 30 parts by weight with respect to 1000 parts by weight of water. 24K N00 ”, diameter 7 μm × 24000 filament, fineness 1.6 g / m, tensile strength 4000 MPa (408 kgf / mm ² ), tensile elastic modulus 238 GPa (24.3 ton / mm ² )) are continuously immersed between the filaments. A carbon fiber sizing agent emulsion was impregnated. This was passed through a drying furnace at 120 ° C. to 150 ° C. for about 40 seconds to be semi-dried and heat-treated to obtain a carbon fiber bundle having a width of about 15 mm.

The water content in the obtained carbon fiber bundle was 13.5 parts by weight with respect to 100 parts by weight of the sum of the weight of the sizing agent adhering to the carbon fiber and the carbon fiber. Moreover, the adhesion amount of the sizing agent in the obtained carbon fiber bundle was 1.48 parts by weight with respect to 100 parts by weight of the carbon fibers.
Two carbon fiber bundles obtained were prepared, and a polypropylene film (Propylene film manufactured by Tosello Co., CPS # 50) was sandwiched between them and bonded at 230 ° C. Then, the length of the bonded portion was 7 mm according to JIS K6850. Tensile shear strength was measured. As a result, high shear strength was obtained as shown in the table.
Moreover, while opening the obtained carbon fiber bundle by opening five holes of φ1 mm in the taper tube, applying a pressure of 0.25 MPa from the outside, and blowing compressed air directly on the fiber bundle, the lower part of the taper tube outlet It was sprayed on the table set up in. When the spread rate was measured by the method described above, as shown in Table 1, a high spread rate was obtained.

[Example 2]
Using the sizing agent prepared in Example 1, the carbon fiber bundle was continuously dipped in the same manner as in Example 1, and the sizing agent emulsion for carbon fiber was impregnated between the filaments. This was passed through a drying furnace at 120 ° C. to 150 ° C. for about 50 seconds to be semi-dried and heat-treated to obtain a carbon fiber bundle having a width of about 15 mm.
The moisture content in the obtained carbon fiber bundle was 6.3 parts by weight with respect to 100 parts by weight of the sum of the weight of the carbon fiber and the sizing agent adhering to the carbon fiber. Moreover, the adhesion amount of the sizing agent in the obtained carbon fiber bundle was 1.33 parts by weight with respect to 100 parts by weight of the carbon fibers.
For the obtained carbon fiber bundle, the tensile shear strength was measured in the same manner as in Example 1. As a result, high shear strength was obtained as shown in Table 1. Further, the fiber opening rate of the obtained carbon fiber bundle was measured in the same manner as in Example 1. The results are shown in Table 1.

[Example 3]
Propylene / ethylene / styrene copolymer (molar ratio of ethylene to propylene 100 is 100, molar ratio of styrene to propylene 100 is 2) 280 parts by weight, maleic anhydride 70 parts by weight, di-tert-butyl peroxide 5.6 A solid material of copolymerized polyolefin was obtained in the same manner as in Example 1 except that 420 parts by weight of toluene and 420 parts by weight of toluene were used. From the measurement result of the infrared absorption spectrum, the copolymerization ratio of maleic anhydride was 0.8 with respect to propylene 100 in molar ratio. Moreover, the weight average molecular weight by high temperature GPC measurement was 82000. Then, a copolymerized polyolefin emulsion was prepared in the same manner as in Example 1, and the obtained copolymerized polyolefin emulsion was continuously immersed in the same carbon fiber bundle as in Example 1, and a sizing agent for carbon fibers between the filaments. The emulsion was impregnated. This was passed through a drying furnace at 120 ° C. to 150 ° C. for about 40 seconds to be semi-dried and heat-treated to obtain a carbon fiber bundle having a width of about 15 mm.

The moisture content in the obtained carbon fiber bundle was 14.7 parts by weight with respect to 100 parts by weight of the sum of the weight of the sizing agent adhering to the carbon fiber and the carbon fiber. Moreover, the adhesion amount of the sizing agent in the obtained carbon fiber bundle was 1.56 parts by weight with respect to 100 parts by weight of the carbon fibers.
For the obtained carbon fiber bundle, the tensile shear strength was measured in the same manner as in Example 1. As a result, high shear strength was obtained as shown in Table 1. Further, the fiber opening rate of the obtained carbon fiber bundle was measured in the same manner as in Example 1. The results are shown in Table 1.

[Example 4]
A 70 L autoclave was charged with 27 kg of ε-caprolactam and 6 kg of 50% aqueous solution of hexamethyleneammonium adipate, and the inside of the polymerization tank was purged with nitrogen, then sealed and heated to 180 ° C. Was adjusted to 17.5 kgf / cm ^2, and the temperature in the polymerization tank was raised to 240 ° C. Two hours after the polymerization temperature reached 240 ° C., the pressure in the polymerization tank was released to normal pressure over about 2 hours. After releasing the pressure, polymerization was performed for 1 hour in a nitrogen stream, and then, vacuum polymerization was performed for 2 hours. After introducing nitrogen and returning to normal pressure, the stirrer was stopped, the strand was extracted and pelletized, and the unreacted monomer was extracted and removed using boiling water and dried. The copolymerization ratio at this time was 6/66 = 90/10 (weight ratio).

  120 g of 6/66 binary copolymer polyamide resin thus obtained, 179.6 g of water and 0.4 g of sodium hydroxide were added into an autoclave equipped with a stirrer, and the state at a rotation speed of 500 rpm was maintained. The temperature was raised to 150 ° C., and the reaction was carried out for 30 minutes at 150 ° C. After completion of the reaction, it was cooled to 50 ° C. as it was, and the polyamide resin aqueous dispersion was taken out. The resin concentration of the obtained aqueous polyamide resin dispersion was 40 parts by weight with respect to 100 parts by weight of the aqueous dispersion. Finally, 75 g of the obtained aqueous polyamide resin dispersion and 3.0 g of an aqueous ammonium lauryl sulfate solution adjusted to 25 parts by weight as an anionic surfactant are mixed to obtain an aqueous dispersion of the polyamide resin composition. It was. This was stirred so that the copolymerized polyamide was 30 parts by weight with respect to 1000 parts by weight of water to prepare a sizing agent emulsion, and the resulting copolymerized polyamide emulsion was used in the same carbon fiber bundle as in Example 1. The carbon fiber sizing agent emulsion was impregnated between the filaments. This was passed through a drying furnace at 120 ° C. to 150 ° C. for about 40 seconds to be semi-dried and heat-treated to obtain a carbon fiber bundle having a width of about 15 mm.

The moisture content in the obtained carbon fiber bundle was 16.7 parts by weight with respect to 100 parts by weight of the sum of the weight of the sizing agent adhering to the carbon fiber and the carbon fiber. Moreover, the adhesion amount of the sizing agent in the obtained carbon fiber bundle was 1.70 parts by weight with respect to 100 parts by weight of the carbon fibers.
For the obtained carbon fiber bundle, the tensile shear strength was measured in the same manner as in Example 1 except that the film used was made of Unitika emblem (30 μm thickness) and the adhesion width was 3 mm. As a result, high shear strength was obtained as shown in Table 1.
Moreover, the fiber opening rate was measured about the obtained carbon fiber bundle. The results are shown in Table 1.

[Comparative Example 1]
A sizing agent emulsion was obtained in the same manner as in Example 1 except that the amount of the partially copolymerized polyolefin was 20 parts by weight with respect to 1000 parts by weight of water. To a stirred sizing agent bath, unsized carbon fiber strand (manufactured by Toho Tenax Co., Ltd., registered trademark “Tenax STS-24K N00”, diameter 7 μm × 24000 filament, fineness 1.6 g / m, tensile strength 4000 MPa (408 kgf / mm ² ) and tensile modulus 238 GPa (24.3 ton / mm ² )) were continuously dipped, and the sizing agent emulsion for carbon fiber was impregnated between the filaments. This was passed through a drying furnace at 150 to 180 ° C. for about 60 seconds to complete drying and heat treatment (no moisture) to obtain a carbon fiber bundle having a width of about 15 mm. The adhesion amount of the sizing agent in the obtained carbon fiber bundle was 1.28 parts by weight with respect to 100 parts by weight of the carbon fibers.
For the obtained carbon fiber bundle, the tensile shear strength was measured in the same manner as in Example 1. As a result, high shear strength was obtained as shown in Table 1. Moreover, the fiber opening rate was measured about the obtained carbon fiber bundle. The results are shown in Table 1.

[Comparative Example 2]
A sizing agent emulsion was obtained in the same manner as in Example 3 except that the copolymerized polyolefin was 20 parts by weight with respect to 1000 parts by weight of water. To a stirred sizing agent bath, unsized carbon fiber strand (manufactured by Toho Tenax Co., Ltd., registered trademark “Tenax STS-24K N00”, diameter 7 μm × 24000 filament, fineness 1.6 g / m, tensile strength 4000 MPa (408 kgf / mm ² ) and tensile modulus 238 GPa (24.3 ton / mm ² )) were continuously dipped, and the sizing agent emulsion for carbon fiber was impregnated between the filaments. This was passed through a drying furnace at 150 to 180 ° C. for about 60 seconds to complete drying and heat treatment (no moisture) to obtain a carbon fiber bundle having a width of about 15 mm. The adhesion amount of the sizing agent in the obtained carbon fiber bundle was 1.33 parts by weight with respect to 100 parts by weight of the carbon fibers.
For the obtained carbon fiber bundle, the tensile shear strength was measured in the same manner as in Example 1. As a result, high shear strength was obtained as shown in Table 1. Moreover, the fiber opening rate was measured about the obtained carbon fiber bundle. The results are shown in Table 1.

[Comparative Example 3]
A sizing agent emulsion was obtained in the same manner as in Example 1 except that the copolymerized polyolefin was adjusted to 20 parts by weight with respect to 1000 parts by weight of water. To a stirred sizing agent bath, unsized carbon fiber strand (manufactured by Toho Tenax Co., Ltd., registered trademark “Tenax STS-24K N00”, diameter 7 μm × 24000 filament, fineness 1.6 g / m, tensile strength 4000 MPa (408 kgf / mm ² ) and tensile modulus 238 GPa (24.3 ton / mm ² )) were continuously dipped, and the sizing agent emulsion for carbon fiber was impregnated between the filaments. This was passed through a drying furnace at 150 to 180 ° C. for about 25 seconds to be semi-dried and heat-treated to obtain a carbon fiber bundle having a width of about 14 mm.
The water content in the obtained carbon fiber bundle was 29.5 parts by weight with respect to 100 parts by weight of the sum of the weight of the sizing agent adhering to the carbon fiber and the carbon fiber. Moreover, the adhesion amount of the sizing agent in the obtained carbon fiber bundle was 1.70 parts by weight with respect to 100 parts by weight of the carbon fibers. For the obtained carbon fiber bundle, the tensile shear strength was measured in the same manner as in Example 1. As a result, high shear strength was obtained as shown in Table 1.
Further, for the obtained carbon fiber bundle, an attempt was made to measure the fiber opening rate by the same method as in Example 1. However, the carbon fiber bundle was wound around the apparatus at the stage of obtaining the sample, and the sample could not be produced.

[Comparative Example 4]
A sizing agent emulsion was obtained in the same manner as in Example 1 except that the same copolymerized polyamide as in Example 4 was prepared to 20 parts by weight with respect to 1000 parts by weight of water. In a sizing agent emulsion bath, an unsized carbon fiber strand (manufactured by Toho Tenax Co., Ltd., registered trademark “Tenax STS-24K N00”, diameter 7 μm × 24000 filament, fineness 1.6 g / m, tensile strength 4000 MPa (408 kgf / mm ² ), And a tensile elastic modulus of 238 GPa (24.3 ton / mm ² )) was continuously immersed, and a sizing agent emulsion for carbon fiber was impregnated between the filaments. This was passed through a drying furnace at 150 to 180 ° C. for about 60 seconds to complete drying and heat treatment to obtain a carbon fiber bundle having a width of about 13 mm.
The adhesion amount of the sizing agent in the obtained carbon fiber bundle was 1.15 parts by weight with respect to 100 parts by weight of the carbon fibers.
For the obtained carbon fiber bundle, the tensile shear strength was measured in the same manner as in Example 4. As a result, high shear strength was obtained as shown in Table 1.
Further, the fiber opening rate of the obtained carbon fiber bundle was measured in the same manner as in Example 1. The results are shown in Table 1.

[Comparative Example 5]
Polyoxyethylene alkyl ether surfactant (trade name “Emulgen 103” manufactured by Kao Corporation), which is a nonionic surfactant that is added to the same copolymerized polyolefin as in Example 1 by the same operation. An emulsion was obtained in the same manner as in Example 1 except that the amount was added so as to be 100 parts by weight with respect to 100 parts by weight of the copolymerized polyolefin.
This was mixed with a non-sized carbon fiber strand (manufactured by Toho Tenax Co., Ltd., registered trademark "Tenax STS- 24K N00 ”, diameter 7 μm × 24000 filament, fineness 1.6 g / m, tensile strength 4000 MPa (408 kgf / mm ² ), tensile elastic modulus 238 GPa (24.3 ton / mm ² )) are continuously immersed between the filaments. A carbon fiber sizing agent emulsion was impregnated. This was passed through a drying furnace at 120 ° C. to 150 ° C. for about 60 seconds to complete drying and heat treatment (no moisture), and a carbon fiber bundle having a width of about 14 mm was obtained. The adhesion amount of the sizing agent in the obtained carbon fiber bundle was 1.20 parts by weight with respect to 100 parts by weight of the carbon fibers.
Further, the tensile shear strength of the obtained carbon fiber bundle was measured in the same manner as in Example 1. As a result, as shown in Table 1, a slightly lower shear strength was obtained as compared with Examples 1 and 2.
Furthermore, the fiber-opening rate was measured about the obtained carbon fiber bundle. The results are shown in Table 1. An increase in the fiber opening rate was observed by including a large amount of the surfactant.

[Example 5]
As a matrix resin, a prime polymer polypropylene “Prime Polypro J108M” (registered trademark) pellets were frozen and ground, and powders having an average particle size of about 1 mm classified by 20 mesh and 30 mesh were prepared. The obtained carbon fiber bundle cut into 16 mm and polypropylene powder were introduced into a tapered tube with the carbon fiber supply rate set to 450 g / min and the polypropylene powder supply rate set to 550 g / min.
While blowing the air onto the carbon fiber in the tapered tube to partially open the fiber bundle, it was sprayed on a table installed at the bottom of the tapered tube outlet together with the polypropylene powder. The dispersed carbon fiber and polypropylene powder were sucked from the lower part of the table with a blower and fixed to obtain a carbon fiber random mat having a thickness of about 5 mm.
The obtained carbon fiber random mat was heated for 5 minutes at 3 MPa in a press apparatus heated to 240 ° C., and a carbon fiber random mat composite having a basis weight of 2350 g / m ² , a thickness of 2.0 mm, and a fiber volume content of 30 Vol%. A material molding board was obtained. This was made into the bending test piece based on JIS7074, and the bending strength and the bending elastic modulus were measured. The results are shown in Table 2.

[Example 6]
A random mat composite material molded plate was obtained in the same manner as in Example 5 except that the carbon fiber bundle obtained in Example 2 was used. This was made into the bending test piece based on JIS7074, and the bending strength and the bending elastic modulus were measured. The results are shown in Table 2.

[Example 7]
A random mat composite material molded plate was obtained in the same manner as in Example 5 except that the carbon fiber bundle obtained in Example 3 was used. This was made into the bending test piece based on JIS7074, and the bending strength and the bending elastic modulus were measured. The results are shown in Table 2.

[Example 8]
The carbon fiber bundle obtained in Example 4 was cut to 16 mm, and Unitika's “A1030FP” PA6 resin powder was set at a carbon fiber supply rate of 450 g / min and a PA6 resin powder supply rate of 690 g / min. And introduced into the taper tube.
While the fiber bundle was partially opened by blowing air onto the carbon fiber in the taper tube, it was sprayed on a table installed at the lower part of the taper tube outlet together with PA6 resin powder. The dispersed carbon fibers and PA6 resin powder were sucked from the bottom of the table with a blower and fixed to obtain a carbon fiber random mat having a thickness of about 5 mm.
The obtained carbon fiber random mat is heated at 260 ° C. for 5 minutes at 3 MPa, and a carbon fiber random mat composite having a basis weight of 2600 g / m ² , a thickness of 2.0 mm, and a fiber volume content of 30 Vol%. A material molding board was obtained. This was made into the bending test piece based on JIS7074, and the bending strength and the bending elastic modulus were measured. The results are shown in Table 2.

[Comparative Example 6]
A random mat composite material molded plate was obtained in the same manner as in Example 5 except that the carbon fiber bundle obtained in Comparative Example 1 was used. This was made into the bending test piece based on JIS7074, and the bending strength and the bending elastic modulus were measured. The results are shown in Table 2.

[Comparative Example 7]
A random mat composite material molded plate was obtained in the same manner as in Example 5 except that the carbon fiber bundle obtained in Comparative Example 2 was used. This was made into the bending test piece based on JIS7074, and the bending strength and the bending elastic modulus were measured. The results are shown in Table 2.

[Comparative Example 8]
Using the carbon fiber bundle obtained in Comparative Example 3, an attempt was made to obtain a random mat composite material molded plate in the same manner as in Example 5. However, in the middle of the process, as in Comparative Example 3, the carbon fiber bundle was obtained. Wraps around the device and a normal random mat could not be obtained.

[Comparative Example 9]
A random mat composite material molded plate was obtained in the same manner as in Example 5 except that the carbon fiber bundle obtained in Comparative Example 4 was used. This was made into the bending test piece based on JIS7074, and the bending strength and the bending elastic modulus were measured. The results are shown in Table 2.

[Comparative Example 10]
A random mat composite material molded plate was obtained in the same manner as in Example 5 except that the carbon fiber bundle obtained in Comparative Example 5 was used. This was made into the bending test piece based on JIS7074, and the bending strength and the bending elastic modulus were measured. The results are shown in Table 2.

Claims (7)

  A carbon fiber bundle is provided with a dispersion composed of a sizing agent containing a surfactant and water, and the water content is 1 to 20 parts by weight with respect to 100 parts by weight of the carbon fiber. A method for producing an opened carbon fiber bundle, which is subjected to an opening process.   The manufacturing method of the opened carbon fiber bundle of Claim 1 which provides a dispersion liquid so that 0.01-10 weight part of sizing agents may adhere with respect to 100 weight part of carbon fiber bundles.   The method for producing an opened carbon fiber bundle according to claim 1 or 2, wherein the sizing agent contains 0.01 to 8 parts by weight of a surfactant with respect to 100 parts by weight of the resin solid content.   The opened carbon fiber bundle obtained by the method according to any one of claims 1 to 3, wherein an adhesion amount of the sizing agent is 0.01 to 10 parts by weight with respect to 100 parts by weight of the carbon fibers.   Compressed air that is cut into a 20 mm fiber bundle, introduced into a tapered tube having a carbon fiber inlet diameter of 20 mm, an outlet diameter of 55 mm, and a length of 400 mm from the inlet to the outlet. When the weight ratio of the fiber bundle having a width of less than 0.6 mm present in the whole fiber after being blown by flowing compressed air so that the pressure is 0.25 MPa is defined as the opening ratio, the opening ratio is The spread carbon fiber bundle according to claim 4, which is 40% or more.   A carbon fiber product obtained from the opened carbon fiber bundle according to any one of claims 4 to 5.   The carbon fiber product according to claim 6, which is a random mat.