JP2002173873A - Carbon fiber strand, its package and method for producing carbon fiber sheet - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a carbon fiber strand having spreadability and scratch resistance. SOLUTION: The carbon fiber strand is composed of a bundle of plural filaments having a sizing agent attached to the filaments. The penetrance (t/(a×b)) of a methyl ethyl ketone solution of an epoxy resin having a viscosity of 10 mPa.s (10 cPs) at 25 deg.C in the carbon fiber strand satisfies the formula 0<t/(a×b)<=0.50; wherein t (sec) is the time necessary for impregnating the solution to the strand piece of the carbon fiber strand; a (mm) is the width of the carbon fiber strand; and b (mm) is the length of the strand piece of the carbon fiber strand. The carbon fiber strand is surface-coated with a sizing agent containing [I] an epoxy resin taking liquid state at 25 deg.C and/or [II] an epoxy resin taking semisolid or solid state at 25 deg.C as main components and [III] a polyhydric alcohol fatty acid ester and/or [IV] a polyoxyalkylene compound as active components.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a carbon fiber yarn which simultaneously satisfies the spreading property and the abrasion resistance, a packaged material thereof, and a method for producing a carbon fiber sheet.

[0002]

2. Description of the Related Art Carbon fibers exhibit extremely high specific strength and specific elastic modulus, and furthermore have excellent heat resistance, and are widely used as reinforcing fibers for composite materials. Is low and has poor flex wear resistance, and in processing steps such as sheet production of prepreg and forming such as filament winding, yarn breakage due to single yarn breakage, cutting and fuzzing often occur, resulting in deterioration of product quality .

[0003] Among the above-mentioned processing steps, when preparing a prepreg, first, carbon fiber yarns (thousands to tens of thousands of carbon fibers sized to give a bundle) are subjected to friction with a metal guide. In general, the matrix resin is impregnated with a matrix resin while being aligned in one direction to form a unidirectionally oriented prepreg (a so-called UD prepreg).
The UD prepreg manufacturing process includes a hot melt method. In addition, one carbon fiber thread is pulled out while being continuously passed through a solvent in which the matrix resin is dissolved, and the carbon fiber thread is spread while being rubbed with a metal guide, and spirally wound around a drum to be unidirectionally oriented prepreg. The solvent method is also generally known. In any of these methods, the carbon fiber thread is rubbed with the metal guide and spread, so that fluff is likely to occur.

[0004] In order to solve such a problem, a sizing agent is conventionally applied to carbon fibers to protect the fiber surface with an appropriate resin film and at the same time to impart flexibility and convergence, thereby providing a fluff due to breakage of single yarn. Technologies have been proposed to reduce the processing and improve workability and handling.

[0005] On the other hand, recently, as studies have been made to reduce the weight of products, there has been a demand for thinner prepregs, that is, prepregs having a low carbon fiber weight. However, the carbon fiber yarn to which the sizing agent has been applied has a sizing property due to the effect of the resin film, and thus is difficult to spread, and it is difficult to prepare a prepreg having a low carbon fiber weight. For this reason, studies have been made to further expand the carbon fiber yarn.

Japanese Patent Publication No. Sho 62-56266 and Japanese Unexamined Patent Publication No.
In Japanese Patent No. -307979, the sizing agent containing an epoxy resin as a main component has an appropriate viscosity at 25 ° C. or 50 ° C. to improve the convergence of a carbon fiber yarn to which the sizing agent has been applied. However, since the convergence was too high, it was not possible to uniformly and greatly expand the carbon fiber yarn during UD prepreg production.

In JP-A-7-197381 and JP-A-9-250087, an abrasion resistance is improved by blending an ester resin or a urethane resin with a sizing agent containing an epoxy resin as a main component. I have. However, since the rubbing with the metal guide is suppressed as much as possible for the purpose of suppressing the fluff, the carbon fiber yarn cannot be uniformly and largely expanded during the production of the UD prepreg. In addition, since an epoxy resin is generally used as a matrix resin of a carbon fiber composite material, adding a large amount of a component other than an epoxy resin such as an ester resin to a sizing agent leads to a decrease in composite characteristics of the composite material. Is concerned.

As described above, in the prior art,
A sizing agent effective for improving both the abrasion resistance and the spreading property, the carbon fiber yarns provided with the sizing agent, and the characteristics of the carbon fiber yarns have not been grasped.

[0009]

SUMMARY OF THE INVENTION In view of the background of the prior art, the present invention is capable of uniformly and greatly expanding a carbon fiber thread in a process of manufacturing a carbon fiber sheet represented by a UD prepreg, and In addition to having excellent scratch resistance,
It is another object of the present invention to provide a carbon fiber thread capable of producing a low-weight carbon fiber sheet, a package thereof, and a method of producing the carbon fiber sheet.

[0010]

The present invention employs the following means in order to solve the above-mentioned problems. That is, the carbon fiber yarn of the present invention is a carbon fiber yarn composed of a bundle of a plurality of single yarns to which a sizing agent is attached, and has a viscosity at 25 ° C. of 10 mPa · s.
Permeability (t / (a) of a (10 centipoise) epoxy resin methyl ethyl ketone solution into the carbon fiber yarn.
× b)) is characterized by satisfying the following expression.

0 <t / (a × b) ≦ 0.50 t (sec): Time required for the resin solution to penetrate into the carbon fiber yarn a piece (a) (mm): Carbon fiber yarn Strip width b (mm): length of the thread of carbon fiber thread The carbon fiber thread of the present invention comprises the following main components of the epoxy resin [I] and / or [II] and the following [III] And / or a surface sizing agent containing the compound of [IV] as an active ingredient.

[I]: epoxy resin liquid at 25 ° C. [II]: semi-solid or solid epoxy resin at 25 ° C. [III]: fatty acid ester of polyhydric alcohol [IV]: polyoxyalkylene compound In the package of carbon fiber yarn, the carbon fiber yarn is 0.60 × 10 ^{−3 to} 0.90 × 10
It is characterized by being continuously wound with a yarn width of ^-3 mm / decitex.

Further, according to the method for producing a carbon fiber sheet of the present invention, either the carbon fiber yarn or the carbon fiber yarn taken out from the package-like material has a spreading ratio of 2.0 to 3 represented by the following formula. .2 are arranged in parallel.

Spreading ratio = c / a a: Thread width of carbon fiber thread (mm) c: Average thread width of one carbon fiber thread in a carbon fiber sheet (mm)

[0015]

BEST MODE FOR CARRYING OUT THE INVENTION The present invention relates to a carbon fiber yarn which is capable of uniformly and greatly expanding a carbon fiber yarn in a carbon fiber sheet manufacturing process and has excellent scratch resistance. The enthusiastic study was conducted to find a solution to such a problem at once.

That is, the carbon fiber yarn of the present invention is a yarn formed by bundling a plurality of single carbon fiber yarns to which a sizing agent is attached, and has a permeability measured by a method defined below. It is important that is specific.

That is, the viscosity at 25 ° C. is 10 mP
When the following cut sample made of the carbon fiber thread is floated on the liquid surface of a · s (10 centipoise) resin solution (a solution in which an epoxy resin is dissolved in methyl ethyl ketone), all parts of the sample become resin. The time t (second) until the resin disappears from the solution surface and starts to sink in the resin solution is measured, and the permeability S to the carbon fiber yarn is calculated by the following equation (1).

Permeability S = t / (a × b) (1) t (seconds): Time required for resin solution to penetrate into carbon fiber yarns a (mm): carbon fiber Yarn width of the yarn b (mm): length of the yarn piece of the carbon fiber yarn In the present invention, the permeability S needs to satisfy the following expression (2).

0 <S ≦ 0.50 (2) The specific procedure for measuring the permeability S is as follows. First, after measuring the width a (mm) of the carbon fiber yarn on the surface of the package-like material, scissors are inserted so as to be substantially perpendicular to the longitudinal direction of the yarn, and n = 5 cut out yarn pieces. Then, each yarn length b (mm) is measured. At this time, the sample is cut while sandwiching the sample portion so that the form of the carbon fiber thread does not collapse. In addition, it cuts so that b may be in the range of 10-20 mm.

Next, the sample was prepared by mixing a resin obtained by mixing Epicoat 828 and Epicoat 1001 at a weight ratio of 1: 3 with methyl ethyl ketone at a weight ratio of 55:45. The viscosity at room temperature and 25 ° C. was 10 mPa · s. Gently put on the solution, and measure the time t (second) until all parts of the thread strip disappear from the solution surface and start to sink in the solution five times in total, and use the average value thereof. .

At this time, the viscosity may vary due to the deviation of the measurement or the mixing ratio. However, since the permeability is determined mainly by the penetration rate of methyl ethyl ketone, if the viscosity is in the range of 10 ± 4 mPa · s. The degree of penetration is sufficiently reliable with the value calculated by the equation (1).

When the permeability of the carbon fiber yarn exceeds 0.50, it becomes particularly remarkable by the solvent method, but the resin solution passes through the widening step before being sufficiently impregnated into the carbon fiber yarn. For this reason, in the widening step, the single yarns within the yarn keep the bunching property, and it is not possible to obtain a sufficient spreading property. On the other hand, if the permeability is 0.50 or less,
The resin solution quickly impregnates the periphery of the single yarns constituting the yarns, whereby the single yarns easily move, so that the carbon fiber yarns can be easily spread during the widening step.

The permeability of the carbon fiber yarn is 0 <S ≦
It may be 0.50, but preferably 0.20
It is preferable that <S ≦ 0.50. That is, when the permeability is less than 0.20, it is preferable that the resin quickly impregnates the carbon fiber yarn, but in particular, when the carbon fiber sheet is produced by the solvent method, the amount of the resin adhering to the carbon fiber yarn is reduced. This is because it becomes excessive and control becomes difficult.

The sizing agent according to the present invention has a content of 0.2
It is preferable that it is attached to the carbon fiber in the range of up to 3.0% by weight.

That is, the amount of the sizing agent applied is 0.
When the amount is less than 2% by weight, when the yarn is expanded, the yarn cannot easily withstand friction caused by a metal guide or the like that passes therethrough, so that the yarn tends to be fuzzy, and the quality of the carbon fiber sheet is deteriorated. On the other hand, if the amount of the sizing agent is more than 3.0% by weight, it is difficult to impregnate the matrix resin such as an epoxy resin into the carbon fiber yarn because the resin film impairs the unfavorably.

Next, the carbon fiber yarn of the present invention preferably has a kinetic friction coefficient with respect to the chrome mirror surface defined below of 0.3 or more, because the spreading property is further improved. However, if it exceeds 0.7, the fluff due to abrasion tends to increase, and the quality of the carbon fiber sheet deteriorates. Therefore, the dynamic friction coefficient is more preferably in the range of 0.3 to 0.7, and 0.4 to 0.7. 0.6 is particularly preferred.

The dynamic friction coefficient referred to here is measured in the following procedure.

That is, the carbon fiber yarn to which the sizing agent is adhered, preferably 0.2 to 3.0% by weight,
Through the fourth four stainless steel chrome mirror guides (a cylinder having a diameter of 9.5 mm) so that each contact angle is 57 ± 3 °, and rubbed at room temperature at a speed of 3 m / min. At this time, the tension on the upstream (unwinding) side of the first mirror surface guide is T1 = 50.
The brake of the unwinding bobbin is adjusted to be 0 g, the tension T2 on the downstream (winding) side of the fourth mirror guide is measured, and the dynamic friction coefficient μ is calculated by the following equation.

Μ = Ln (T2 / T1) / θ μ: dynamic friction coefficient T1: tension on the upstream side of the first mirror guide (= 500)
[G] T2: tension on the downstream side of the fourth mirror guide [g] θ: total contact angle (= 4.0) [rad] The carbon fiber thread of the present invention has the following [I] and / or [II] ], And a surface of which is coated with a sizing agent containing, as an active ingredient, a main component of the epoxy resin of the present invention and a compound of the following [III] and / or [IV].

[I]: epoxy resin liquid at 25 ° C. [II]: semi-solid or solid epoxy resin at 25 ° C. [III]: polyhydric alcohol fatty acid ester [IV]: polyoxyalkylene compound 0.2-3.0 for carbon fiber yarn
It is preferable that the carbon fiber yarn is adhered in the range of weight%, and the carbon fiber yarns satisfying the above-mentioned permeability and friction coefficient conveniently and having good spreadability can be preferably provided.

As the epoxy resin of [I], 2
Any liquid at 5 ° C. may be used. For example, a glycidyl-based epoxy resin and a non-glycidyl-based (peracetic acid-based) epoxy resin can be used.

As the glycidyl epoxy resin, the following four types can be used. (1) Bisphenol type epoxy resin 2,2-bis (4-hydroxyphenyl) propane [bisphenol A], 2,2-bis (4-hydroxyphenyl) methane [bisphenol F], 2,2-bis (4
Condensates of bisphenols such as -hydroxyphenyl) ethane and 2,2-bis (4-hydroxyphenyl) butane with epichlorohydrin (2) Phenol novolak type epoxy resin Novolak type phenol resin and epichlorohydrin Reactant (3) Ester type epoxy resin Copolymer of ethylenic double bond-containing monomer such as acrylonitrile, styrene, vinyl acetate, vinyl chloride and glycidyl methacrylate (4) Ether type epoxy resin Polyol or polyether Reaction product of epichlorohydrin with ether such as polyol As the non-glycidyl epoxy resin, epoxidized butadiene, epoxidized glyceride, epoxidized soybean oil and the like are used.

These epoxy resins may be used alone or
Two or more types can be used in combination. Among the above epoxy resins, a bisphenol-type glycidyl-based epoxy resin is preferable, and a bisphenol-A-type glycidyl-based epoxy resin is more preferably used.

The bisphenol A type glycidyl epoxy resin has a viscosity at 25 ° C. of preferably 300 to 2500 centipoise, and more preferably 9 centipoise.
Those having a size of 00 to 1500 centipoise are used. The epoxy equivalent of the epoxy resin represented by the number of grams of a resin containing an epoxy group equivalent to 1 gram is preferably 150 to 250, and more preferably 180 to 200. Specific examples of the bisphenol A type glycidyl epoxy resin include Epicoat 825, Epicoat 827, Epicoat 828, Epicoat 828EL, Epicoat 8 manufactured by Japan Epoxy Resin Co., Ltd.
28XA and the like can be preferably used.

Next, as the epoxy resin of [II], 2
The semi-solid may be a semi-solid or a solid at 5 ° C., and the term “semi-solid” as used herein means a highly viscous liquid having a viscosity at 25 ° C. of 1,000 centipoise or more, preferably 10,000 centipoise or more. As such an epoxy resin, a bisphenol-type glycidyl-based epoxy resin is preferable, and a bisphenol-A-type glycidyl-based epoxy resin is more preferably used. Among such bisphenolphenol A-type glycidyl-based epoxy resins, those having an epoxy equivalent of 200 to 1000 are preferable, and those having an epoxy equivalent of 200 to 50 are preferable.
0 is more preferably used.

Specific examples of the bisphenol A type glycidyl epoxy resin include Epicoat 834 and Epicoat 1001, manufactured by Japan Epoxy Resins Co., Ltd.
Epicoat 1002, Epicoat 1003, Epicoat 1003F, Epicoat 1004, Epicoat 1004
F, Epicoat 1004AF, Epicoat 1055, or the like can be used.

When the amount of the compound (I) or (II) is less than 50% by weight, the adhesion to the matrix resin is poor. On the other hand, when the amount exceeds 95% by weight, the stability of the sizing agent itself is poor. Therefore, it is preferable to mix 50 to 95% by weight, more preferably 80 to 90% by weight. When the compound of both [I] and [II] is contained, if the compounding ratio of the compound of [II] / [I] exceeds 3.0, the convergence is reduced and the handling property of the yarn is reduced. From the viewpoint of deterioration, 0.0 to 3.0 is preferable, further preferably 0.2 to 1.5, and still more preferably 0.3 to 0.3.
It is better to mix in the range of 6.

Next, the compound [III] is an ester composed of a polyhydric alcohol and a fatty acid. As the polyhydric alcohol constituting the ester, glycerin, pentaerythritol, sorbit and sorbitan are preferably used. As the fatty acid constituting the ester, a saturated or unsaturated carboxylic acid having 12 to 22 carbon atoms or a saturated or unsaturated hydroxy carboxylic acid having 12 to 22 carbon atoms is preferably used. Hydrogenated ricinoleic acid (saturated), ricinoleic acid (unsaturated)
Is particularly preferably used.

Among these polyhydric alcohol fatty acid esters, those obtained by adding ethylene oxide to hydroxyl groups derived from polyhydric alcohols and / or hydroxyl groups derived from hydroxycarboxylic acids are more preferable, and the number of moles of ethylene oxide added is particularly preferable. Those having 100 to 200 are preferred.

Next, the compound of [IV] is a compound having 2 carbon atoms.
Compounds comprising up to 6 branched or unbranched alkylene oxides are used. As the alkylene oxide, a compound having 2 and / or 3 carbon atoms of ethylene oxide (EO) and / or propylene oxide (PO) is preferably used.
Are randomly or block copolymerized, and the EO / PO molar ratio is preferably from 50/50 to
100/0, more preferably 70/30 to 90/10
Having a molecular weight of preferably 6000 to 22000,
More preferably, a polyoxyalkylene compound having a molecular weight of 10,000 to 18,000, particularly preferably 14,000 to 18,000 is used.

When the amount of the compound [III] or [IV] is less than 5% by weight, the stability of the sizing agent itself is deteriorated. When the amount exceeds 50% by weight, the adhesion to the matrix resin is deteriorated. Therefore, the compound of [III] or [IV] is preferably 5 to 50% by weight, more preferably 10 to 50% by weight.
-20% by weight is preferred. When both the compounds [III] and [IV] are contained, the compounding ratio of the compound [IV] / [III] is from 0.0 to 1.
0, more preferably 0.0 to 0.1.
It is better to mix in the range of 5.

In the present invention, the form of the compounds [I] to [IV] is not particularly limited, but is preferably a sizing agent solution dispersed or diluted in a solvent such as water or an organic solvent. .

The carbon fiber yarn of the present invention has a solid content obtained by absolutely drying at least the sizing agent (including a solvent) adhering to the surface thereof, that is, the viscosity of the active ingredient,
It is preferable from the viewpoint of the spreading property that it is 200 mPa · s or less, but if it is less than 10 mPa · s, the convergence of the carbon fiber yarn is reduced, and the handleability of the yarn is deteriorated. Is more preferable, and more preferably 50 to 100 mPa · s, from the viewpoints of spreadability and scratch resistance.

Further, the carbon fiber yarn of the present invention is preferably in the form of a package in which the yarn is continuously wound from the viewpoint of handleability, and the carbon fiber yarn on the surface of the packaged material per unit fineness of the carbon fiber yarn is preferable. The thread width is 0.60 × 1
When the diameter is 0 ^-3 mm / decite or more, it is preferable because the width in the manufacturing process of the carbon fiber sheet is easy.
If it exceeds 0.90 × 10 ⁻³ mm / decitex, it becomes difficult to handle, for example, the yarn unwound from the package is folded by a guide, so that the preferable yarn width is 0.60 × 10 3. ^{−3 to} 0.90 × 10 ⁻³ mm / decitex.

The carbon fiber yarn package of the present invention preferably has a wind ratio of 6 to 14.
When the wind ratio is less than 6, when unwinding the carbon fiber thread from the package, the number of traverses increases, twisting or breaking of the thread occurs, and a portion having poor spreadability on the carbon fiber sheet, that is, When the wind ratio exceeds 14, on the other hand, when the wind ratio exceeds 14, the yarn angle on the surface of the package decreases, and the form stability during transportation of the package decreases. It is because it falls.

Incidentally, the wind ratio is determined by rotating the package while the carbon fiber thread is traversed by one when the carbon fiber thread is continuously unwound from the package inserted into the rotatable creel. Is a number.

The weight of the carbon fibers in the package is not particularly limited, but is preferably selected, for example, in the range of 2 to 10 kg.

The method for producing a carbon fiber sheet according to the present invention is characterized in that the carbon fiber yarn or the carbon fiber yarn taken out from the packaged material has a spreading ratio represented by the following formula of 2.0 to 2.0.
3.2 are arranged in parallel.

Spreading rate = c / a a: Thread width of carbon fiber thread (mm) c: Average thread width of the carbon fiber thread in carbon fiber sheet (mm) When the spreading rate is less than 2.0, Due to insufficient spreadability, a portion where no fiber is present (crack) remains between the yarns, and the carbon fiber sheet with a low carbon fiber weight pertaining to the present invention cannot be obtained.

When the spreading ratio exceeds 3.2, the spreadability is good, but the spread is excessive, so that adjacent yarns overlap each other in the carbon fiber sheet, and the sheet width is increased. The thickness unevenness in the direction becomes remarkable, and cracks easily occur in thin portions, which is not preferable.

The carbon fiber yarn of the present invention can be used as a dry carbon fiber sheet such as a woven fabric or a UD sheet because of its good spreadability. However, it is preferably used as a material for a UD prepreg which requires a particularly large expansion ratio. used. In addition, in the solvent method in which one carbon fiber thread is wound around a drum after impregnation with a resin solution, the winding speed is very high, and the winding tension is high, so that the effect of the present invention is sufficiently exhibited. Is what is done.

The carbon fiber thread of the present invention is a bundle of thousands to tens of thousands of known carbon fiber filaments such as polyacrylonitrile (PAN), rayon or pitch. PAN-based carbon fibers, from which a strong carbon fiber bundle can be easily obtained, are preferred for obtaining a reinforcing effect. In addition, from the viewpoint of spreadability and scratch resistance in the UD prepreg manufacturing step in the subsequent step, the final product preferably has a total single yarn fineness of 0.4 to 3.0 g / m, and a total number of single yarns. Is preferably 1,000 to 100,000, more preferably 3,000 to 24,000, and the strength is preferably 100 to 1,000 kgf / mm ² , more preferably 200 to 700 kgf / mm ² , and the elastic modulus is preferably 10 to 10 kgf / mm ^2. 100 t / mm ^2, further preferably set to the carbon fiber yarns are preferably 20~60t / mm ^2. The carbon fibers include carbonized fibers and graphite fibers.

Hereinafter, the case of PAN-based carbon fiber will be described in detail.

As the spinning method, a wet method, a dry method, a dry-wet method, or the like can be employed, but a wet method or a dry-wet method is preferred, in which a high-strength, high-strength yarn is easily obtained, and a dry-wet method is particularly preferable. As the spinning solution, a solution or suspension of a polyacrylonitrile homopolymer or copolymer component can be used.

After the spinning solution is solidified, washed and stretched, an oil agent is applied to obtain a precursor fiber. The precursor fiber is subjected to a flame-proofing treatment and a carbonization treatment to form a carbonized fiber, or, if necessary, further graphitized to obtain a graphitized fiber. The obtained carbonized fiber and graphitized fiber are subjected to electrolytic surface treatment and sizing agent application in order to improve the adhesiveness with the matrix resin combined when the composite material is formed. Become.

[0056]

The present invention will be described in more detail with reference to the following examples. In addition, the measuring method in an Example is as follows. (1) After the carbon fiber thread of the sizing agent deposition amount of about 2g were weighed (W1), and allowed to stand in 50 l / min nitrogen gas stream, into an electric furnace set at a temperature 450 ° C. (volume 120 cm ³⁾ 15 minutes, The sizing agent was completely pyrolyzed. Then, the carbon fiber yarn was transferred to a container in a dry nitrogen gas flow of 20 liter / min, cooled for 15 minutes, weighed (W2), and the sizing adhesion amount was determined by the following equation.

Sizing adhesion amount (%) = [W1 (g)-
W2 (g)] / [W1 (g)] × 100 (2) Permeability of resin solution First, scissors are inserted so that the carbon fiber yarn is substantially perpendicular to the longitudinal direction of the yarn. A piece was cut out of n = 5, and each yarn length b (mm) was measured. At this time, the sample was cut while sandwiching the sample portion so that the form of the carbon fiber yarn did not collapse. In addition, b was cut so that it might be in the range of 10 to 20 mm.

Next, the sample was prepared by mixing a resin obtained by mixing Epicoat 828 and Epicoat 1001 at a weight ratio of 1: 3 with methyl ethyl ketone at a weight ratio of 55:45. The viscosity at room temperature and 25 ° C. was 10 mPa · s. Was gently placed on the resin solution, and the time t (second) until all parts of the thread piece disappeared from the resin solution surface and began to sink in the resin solution was measured five times in total, and the average value was used. . The resin solution was placed in the container so as to have a depth of 5 cm or more, so that the sample placed near the center of the liquid surface did not come into contact with the container wall until the sample began to sink.

Finally, using the times t and b and the yarn width a (mm) obtained from the measurement of the following (6),
The permeability was calculated from the following equation.

Permeability = t / (a × b) (3) Viscosity The viscosity of the sizing agent active ingredient was measured using a codex ICI manufactured by keeping a completely dried sizing agent at 50 ° C.
It was measured by a cone plate type viscometer (for high temperature).

The viscosity of the resin solution for evaluating the permeability at 25 ° C. was measured using an E-type viscometer (VISCONI, manufactured by Tokimec Co., Ltd.).
CED type). (4) Dynamic friction coefficient A carbon fiber yarn having a total single yarn fineness of 0.8 g / m and a total number of single yarns of 12,000 to which a sizing agent is adhered is firstly and fourthly made of four stainless steel chrome mirror guides (diameter 9). 0.5mm
Thread) so that each contact angle is 57 ± 3 °,
Rub at room temperature at a speed of 3 m / min. The brake of the unwinding bobbin is adjusted so that the tension T1 on the upstream (unwinding) side of the first mirror guide becomes 500 g, the tension T2 on the downstream (winding) side of the fourth mirror guide is measured, and the dynamic friction coefficient is calculated by the following equation. μ was calculated.

Μ = Ln (T2 / T1) / θ μ: coefficient of friction against metal T1: tension on the upstream side of the first mirror guide (= 500)
[G] T2: tension on the downstream side of the fourth mirror surface guide [g] θ: total contact angle (= 4.0) [rad] (5) Scratch fluff 0.8 g / m of single yarn fineness with sizing agent attached After rubbing a carbon fiber yarn having a total number of single yarns of 12,000 on a chrome mirror surface guide under the same apparatus and conditions as in the above-mentioned measurement of the dynamic friction coefficient, a fluff counting device for special yarn manufactured by Toray Engineering Co., Ltd. [Type: DT- 105 (S characteristic)], and the number of fluff [pieces / m] was measured. (6) Thread width on package surface A ruler is applied to the package surface, and each package n = 10
The points were measured, and the average value r (mm) was taken as the yarn width. still,
The yarn width per unit fineness was determined by dividing this value r by the total decitex number of the carbon fiber yarn (W3 (weight of carbon fiber yarn, measurement method described in (7) below) × 10000). (7) Spreading ratio of carbon fiber yarns When the number of cracks in the carbon fiber sheet (the width is 0.5 mm or more, or the width is less than 0.5 mm but the length is 20 cm or more) is 0.5 or less per m ^2. About something,
The basis weight W3 (g / m) of the carbon fiber thread and the basis weight W4 (g / m ² ) of the carbon fiber sheet are described below (6).
Using the following formula, the thread width r (mm) of the package surface calculated in step (1) was used. W3 and W4 were calculated according to the following procedure.

Spreading rate = (1000 × W3) / (W4 × r) First, the basis weight W3 (g / m) of the carbon fiber yarn is a sample 1 m in length from the carbon fiber yarn before being formed into a carbon fiber sheet. 5
This cut out was taken as the average weight.

Next, the carbon fiber weight of the carbon fiber sheet W4
(G / m ² ) was calculated by the following procedure.

First, three 100 mm × 100 mm test pieces are sampled from a prepreg using a 100 mm × 100 mm template. Next, the test piece is placed in about 200 cc of methylene chloride placed in a 300 cc beaker, allowed to stand at room temperature for about 20 minutes, and stirred twice in the middle to extract the resin while helping to dissolve the resin. At this time, release paper, mesh, which is used to stabilize the sheet form other than resin,
Remove any non-woven fabric. After pulling up the test piece from the beaker, the beaker is inclined and methylene chloride is poured out. The test piece is extracted again with methylene chloride in a beaker, and this is repeated a total of three times. Thereafter, the test piece is filtered, and the test piece is placed on a glass filter. The test piece was placed in a dryer at 120 ± 10 ° C.
Dry for 0 ± 5 minutes. After cooling in a desiccator, the test piece weight was weighed to the nearest 0.1 mg (W5), and the weight of the carbon fiber thread contained in the carbon fiber sheet was calculated from the following formula (W4).
Is calculated.

The carbon fiber weight of the carbon fiber sheet (W4) =
W5 × 100 (g / m ² ) Examples 1 to 10, Comparative Examples 1 to 3 The sizing agent shown in Table 1 was 1 or 0.1 on a carbon fiber yarn having a basis weight of 0.8 g / m and a total number of single yarns of 12,000. The sample was processed so as to adhere to the sample by weight.

The above seven evaluations were performed on these carbon fiber yarns, and the results are shown in Table 2, and an overall judgment was made. In the overall judgment, ◎ and ○ were passed, and × was rejected.

[0068]

[Table 1]

Note 1) The numerical values in the table indicate the contents [% by weight] of each component.

Note 2) The components in the table represent the following compounds.

I-1: Epikote 828 II-1: Epikote 834 II-2: Epikote 1001 III-1: Hydrogenated ricinoleic glyceride EO15
0 mol adduct (hardened castor oil ether EO 150 mol adduct) III-2: pentaerythritol oleate IV-1: EO / PO block copolymer (EO / PO)
= 80/20, molecular weight = 16000) IV-2: EO / PO block copolymer (EO / PO)
= 80/20, molecular weight = 12000) A-1: unsaturated polyester (bisphenol A ethylene oxide 3 mol adduct and maleic anhydride 9:
B-1: stearyl stearate C-1: water-soluble polyurethane (tensile strength = 232 k)
g / cm ² , elongation = 400%, 100% modulus = 7
7 kg / cm ² )

[0072]

[Table 2]

As is clear from Table 2, all of the examples satisfy both good spreadability and abrasion resistance, while those of the comparative examples have at least one of these properties inferior.

[0074]

According to the present invention, the carbon fiber yarns can be uniformly and greatly expanded in the production process of the carbon fiber sheet, so that a high-performance carbon fiber sheet having a low carbon fiber basis weight can be provided. .

────────────────────────────────────────────────── ─── of the front page continued (51) Int.Cl ⁷ identification mark FI theme Court Bu (reference) D06M 101:. 40 D06M 101 : 40 F -term (reference) 4F072 AA04 AA07 AB10 AB22 AC05 AD23 AD28 AD34 AE01 AG03 AG20 AH04 AK05 AK06 4L033 AA09 AB01 AC12 AC15 BA21 CA48 CA49

Claims (9)

[Claims] 1. A carbon fiber yarn comprising a bundle of a plurality of single yarns to which a sizing agent is adhered and having a viscosity at 25 ° C. of 10 mPa · s (10 centipoise) of an epoxy resin in methyl ethyl ketone. A carbon fiber yarn having a permeability (t / (a × b)) with respect to the carbon fiber yarn satisfying the following expression: 0 <t / (a × b) ≦ 0.50 t (second): Time required for the solution to penetrate into the carbon fiber yarn a piece (a) (mm): Carbon fiber yarn width b ( mm): Length of carbon fiber thread 2. The main component of the epoxy resin of the following [I] and / or [II] and the following [III] and / or [IV]
A carbon fiber yarn characterized by being surface-coated with a sizing agent containing the compound of claim 1 as an active ingredient. [I]: epoxy resin liquid at 25 ° C. [II]: semi-solid or solid epoxy resin at 25 ° C. [III]: polyhydric alcohol fatty acid ester [IV]: polyoxyalkylene compound 3. The composition according to claim 1, wherein the sizing agent is contained in an amount of 0.2 to 3.0% by weight.
3 or 4 attached to the surface of the carbon fiber.
The carbon fiber yarn according to the above. 4. The carbon fiber yarn according to claim 1, wherein a dynamic friction coefficient of the carbon fiber yarn with respect to a chrome mirror surface is 0.3 to 0.7. 5. The viscosity of the active ingredient at 50 ° C. is 10 to 10.
The carbon fiber yarn according to claim 2, wherein the carbon fiber yarn has a pressure of 200 mPa · s (10 to 200 centipoise). 6. The carbon fiber according to claim 1,
The thread is 0.60 × 10 ^-3~ 0.90 × 10^-3mm / de
It is characterized by being continuously wound with the thread width of SITEX
A package of carbon fiber yarn. 7. A carbon fiber wherein the carbon fiber yarns according to any one of claims 1 to 5 are arranged in parallel so that a spreading ratio represented by the following formula is 2.0 to 3.2. A method for producing a fiber sheet. Expansion rate = c / a a: Thread width of carbon fiber thread (mm) c: Average thread width of one carbon fiber thread in a carbon fiber sheet (mm) 8. The carbon fiber thread taken out of the package according to claim 6 having a spreading factor of 2.0 to
3. A method for producing a carbon fiber sheet, wherein the carbon fiber sheets are arranged in parallel so as to form 3.2. 9. The method for producing a carbon fiber sheet according to claim 7, wherein the carbon fiber sheet is a prepreg.