JP2003064539A - Carbon fiber fabric and method for producing the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a carbon fiber fabric without showing the oozing out of a treating agent to the untreated surface even on treating one side surface in a thin type fabric, its raw material and methods for producing them. SOLUTION: This carbon fiber fabric consisting of spun yarns or a filament bundle is provided by using monofilaments having a flat cross section for constituting the spun yarns or filament bundle. The method for producing the carbon fiber fabric is provided by spin-processing or intermingle-treating a polyacrylonitrile-based oxidized fiber to obtain the spun yarns or filament bundle, compression-treating the obtained spun yarns or filament bundle at 150-400 deg.C temperature and under 5-50 MPa pressure, fabric-processing and then carbonizing.

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to a current-carrying material (electrode material,
Carbon fiber woven fabric for use as a structural material for earth, etc., its raw material,
And a manufacturing method thereof.

[0002]

2. Description of the Related Art Polyacrylonitrile-based carbon fibers are flexible, thin, and capable of producing electrically conductive fabrics, and are applied as a compact current-carrying material (electrode material, grounding structural material) as a structure. Is expected.

When applied as a current carrying material as a thin carbon fiber woven fabric, water repellent treatment on one side, resin treatment, ceramic treatment, etc. are required, or it is integrated with other functional sheets, etc. It has been commercialized.

The carbon fiber woven fabric is composed of spun yarn and filament bundles. However, if the spun yarns or filament bundles are spaced apart from each other, the resin easily exudes to the non-treated surface during the one-side treatment. Further, even if the spacing between spun yarns and filament bundles is narrow, if the thickness of the carbon fiber woven fabric is thin, the resin tends to ooze out to the non-treated surface during the one-side treatment.

If the treating agent oozes out to the non-treated surface (opposite side) during the one-side treatment of the carbon fiber woven fabric, the treating agent adheres to the contact surface in the process, is contaminated, and further deteriorates the quality of the product.

From the above, the thickness is thinner,
There is a demand for a material that is flexible and does not exude the treatment agent to the non-treated surface during one-side treatment and has excellent electrical conductivity in the thickness direction.

[0007]

Regarding the carbon fiber spun yarn woven fabric, the inventors of the present invention have made the spun yarns which are composed flat by eliminating the gaps between the spun yarns (reducing the gap degree). The application of a processing agent was improved (Japanese Patent Application No. 2001-160232).

However, when the carbon fiber spun yarn fabric is a thin and low basis weight material, or when the carbon fiber fabric is composed of a bundle of filaments, the bleeding of the treating agent was not sufficiently improved.

The inventors of the present invention have conducted further studies as a solution to the above problems, and as a result, improved the porosity and flattened the filaments of the spun yarn or filament bundle, and the flat surface thereof was used as the surface of the woven fabric. By orienting parallel to the plane of
It was found that the exudation of the treatment agent could be further improved, and the present invention was completed.

Therefore, an object of the present invention is to solve the above-mentioned problems, and in a thin woven fabric, a carbon fiber woven fabric in which the treating agent does not seep to the non-treated face even after one-side treatment, its raw material, and It is to provide the manufacturing method of them.

[0011]

The present invention which achieves the above-mentioned object is described below.

[1] A spun yarn or filament bundle containing at least polyacrylonitrile oxide monofilament having a flat cross section.

[2] A carbon fiber woven fabric comprising spun yarns or filament bundles, wherein the single fibers constituting the spun yarns or filament bundles have a flat cross-sectional shape.

[3] Maximum diameter of cross section of single fiber (L ₁ )
And the flatness (L ₂ / L ₁ ) of the single fiber represented by the minimum diameter (L ₂ ) of the cross section of the single fiber is 0.2 to 0.7 [2]
The carbon fiber woven fabric according to 1.

[4] A spun yarn or filament bundle is obtained by spinning or intermingling polyacrylonitrile oxide fiber, and the spun yarn or filament bundle is obtained at a temperature of 150 to 400 ° C. and a pressure of 5 to 5. 50 MPa
A method for producing a spun yarn or filament bundle containing at least polyacrylonitrile oxide monofilament having a flat cross-sectional shape, which is characterized in that compression treatment is performed.

[5] The polyacrylonitrile oxide fiber is spun or intermingled to obtain a spun yarn or filament bundle, and the spun yarn or filament bundle is obtained at a temperature of 150 to 400 ° C. and a pressure of 5 to 5. 50 MPa
A method for producing a carbon fiber woven fabric, which comprises subjecting the woven fabric to compression treatment, then processing the woven fabric, and then carbonizing. The polyacrylonitrile-based fiber is oxidized to obtain an oxidized fiber, the obtained oxidized fiber is spun or intermingled to obtain a spun yarn or filament bundle, and the spun yarn or filament bundle obtained is subjected to a temperature 150 ~ 400 ℃, pressure 5
A method for producing a carbon fiber woven fabric, which comprises compressing at -50 MPa, then processing the woven fabric, and then carbonizing.

[0017]

BEST MODE FOR CARRYING OUT THE INVENTION The present invention will be described in detail below.

The carbon fiber woven fabric of the present invention is a carbon fiber woven fabric comprising a spun yarn or a filament bundle, and a single fiber constituting the spun yarn or the filament bundle has a flat cross section.

In the carbon fiber woven fabric of the present invention, the flatness (L ₂ / L ₁ ) of the single fiber is preferably 0.2 to 0.7.

When the flatness of the single fiber is less than 0.2, the fiber strength is lowered and fine powder is generated, which is not preferable.

When the flatness of the single fiber exceeds 0.7,
This is not preferable because the effect of suppressing the exudation of the treatment agent is reduced.

The flatness of this monofilament is determined by, for example, an electron micrograph of the cross section of the monofilament constituting the spun yarn or filament bundle, showing the maximum diameter (L ₁ ) and the minimum diameter (L ₂ ) of the cross section of the monofilament. Can be obtained by measuring and and calculating the ratio (L ₁ / L ₂ ).

The basis weight of the carbon fiber woven fabric of the present invention is 30 to 1
It is preferably 50 g / m ² .

If the basis weight of the carbon fiber woven fabric is lower than 30 g / m ² , problems such as easy exudation to the back surface during the one-side treatment, a decrease in strength, and an increase in electrical resistance in the thickness direction occur. Not preferable.

When the basis weight of the carbon fiber woven fabric is higher than 150 g / m ² , the electric resistance value in the thickness direction increases and the flattening process of the spun yarn and filament bundle is difficult, which is not preferable. .

The carbon fiber woven fabric of the present invention has a thickness of 0.15.
It is preferably about 0.7 mm.

When the thickness of the carbon fiber woven fabric is less than 0.15 mm, the strength of the carbon fiber spun yarn woven fabric is reduced, cutting and elongation are likely to occur during processing, and workability is reduced. It is not preferable because it causes

When the thickness of the carbon fiber woven fabric exceeds 0.7 mm, the electric resistance value in the thickness direction increases, which is not preferable.

The porosity of the carbon fiber woven fabric of the present invention is preferably 7% or less.

If the carbon fiber woven fabric has a porosity of more than 7%, it tends to seep to the back surface during one-side treatment with a treating agent such as resin or catalyst, and the electrical resistance value in the thickness direction increases (compared with other members). (Due to the reduction of the contact area) and the like, which is not preferable.

The bleeding rate of the treating agent during the one-sided treatment is preferably as small as possible, and 0% is most preferable.

When the exudation rate of the treating agent is higher than 3%, the surface damage and the quality deterioration of the carbon fiber woven fabric due to the attaching and fixing of the treating agent in the process are likely to occur, which is not preferable.

The X-ray crystal size of the carbon fiber woven fabric is 1.3.
~ 4.5 nm is preferred.

The electric resistance value becomes lower as the degree of carbonization / graphitization of carbon increases. This carbonization / graphitization index is
It can be indicated by the size of the X-ray crystal size.

X-ray crystal size of carbon fiber woven fabric is 1.3 n
If it is lower than m, the electric resistance value in the thickness direction increases, which is not preferable.

X-ray crystal size of carbon fiber woven fabric is 4.5n
When it is higher than m, the strength of the carbon fiber spun yarn woven fabric is deteriorated and the generation of carbon fine powder is increased, which is not preferable.

The X-ray crystal size can be adjusted by adjusting the firing temperature and time when carbonizing the carbon fiber woven fabric.

(Production of carbon fiber woven fabric) The carbon fiber woven fabric of the present invention is not particularly limited in its production method as long as the physical properties thereof are within the above-mentioned ranges. For example, polyacrylonitrile fiber ( The precursor) is oxidized to obtain oxidized fiber, the obtained oxidized fiber is spun or intermingled to obtain a spun yarn or filament bundle, and the spun yarn or filament bundle is obtained at a temperature of 1
It can be manufactured by a method of manufacturing a carbon fiber woven fabric in which compression treatment is performed at 50 to 400 ° C. and a pressure of 5 to 50 MPa, and then the woven fabric is processed and then carbonized.

The method for producing the carbon fiber woven fabric of the present invention will be described in detail below.

(Oxidized Fiber) Oxidized fiber, which is a raw material for the carbon fiber woven fabric of the present invention, is obtained by subjecting a polyacrylonitrile precursor to an oxidation treatment in air at an initial oxidation temperature of 220 to 280 ° C.

The proper fineness of the oxidized fiber is 0.8 to 2.8d.
tex. The fineness can be adjusted depending on the fineness of the precursor used and the relaxing conditions at the time of oxidation.

If the fineness of the oxidized fiber is lower than 0.8 dtex, the pressure during the compression process is difficult to reach each single fiber, and the flattening process of the single fiber becomes difficult, which is not preferable.

If the fineness of the oxidized fiber is higher than 2.8 dtex, the oxidation time will be long, the productivity will be poor, and problems such as difficulty in finely processing the spun yarn or filament bundle will occur. .

The proper specific gravity of the oxidized fiber is 1.30 to 1.
39. If the specific gravity of the oxidized fiber is lower than 1.30, the strength of the oxidized fiber is deteriorated during compression, and the carbon fiber fine powder is generated, which is not preferable. If the specific gravity of the oxidized fiber is higher than 1.39, flattening of the single fiber becomes difficult and the compression effect is deteriorated, which is not preferable.

(Oxidized Fiber Woven Fabric) The oxidized fiber is made into an oxidized fiber spun yarn woven fabric or an oxidized fiber filament woven fabric by the following method. Hereinafter, the method for producing each oxidized fiber fabric will be described in detail.

(A: Oxidized fiber spun yarn woven fabric) (a-1: Spinning process) A short fiber cotton material obtained by cutting or bias-cutting an oxidized fiber to a predetermined length is spun and twisted, and the oxidized fiber is added. Get spun yarn.

The thickness of the obtained oxidized fiber spun yarn is preferably 15th count single yarn to 25th count single yarn or 30th count double yarn to 50th count double yarn.

The number of twists of the oxidized fiber spun yarn is preferably 100 to 800 times / m in both cases of upper twist and lower twist.

The number of short fibers of the oxidized fiber spun yarn is 90 to 9
00 / spun yarn is preferred.

(A-2: Compression treatment) The obtained oxidized fiber spun yarn is subjected to compression treatment. You may perform compression processing after resin-treating beforehand. For the resin treatment of the oxidized fiber spun yarn, it is preferable to immerse it in a resin bath having a predetermined concentration to deposit the resin in the range of 10.0% by mass or less.

When the amount of the resin adhered is more than 10.0% by mass, the flexibility of the carbon fiber spun yarn fabric is impaired and brittleness becomes high, which is not preferable.

The resin used for the resin treatment is preferably a water-soluble resin having good handleability such as polyacrylic acid ester, carboxymethyl cellulose and polyvinyl alcohol.

The concentration of the resin bath is preferably 0.1 to 5.0% by mass.

The oxidized fiber spun yarn is subjected to a compression treatment after the resin treatment or without the resin treatment.

The compression treatment temperature is preferably 150 to 400 ° C. When the compression treatment temperature is lower than 150 ° C., the flattening effect of the single fiber is lowered, which is not preferable. When the compression treatment temperature is higher than 400 ° C, the flattening effect of the single fiber is large, but the strength of the oxidized fiber spun yarn after the compression treatment is lowered, and the fabric processability is deteriorated, which is not preferable. .

The pressure during the compression treatment is preferably 5 to 50 MPa. When the pressure is lower than 5 MPa, the flattening effect of the single fiber is lowered, which is not preferable. When the pressure is higher than 50 MPa, the flattening effect of the single fiber is large, but the strength of the oxidized fiber spun yarn after compression is reduced, which is not preferable.

The pressure device used for the compression treatment may be any device such as a hot press or a heat roller.

(A-3: Weaving) An oxidized fiber spun yarn woven fabric is obtained by weaving the compressed oxidized fiber spun yarn. The form of the oxidized fiber spun yarn fabric is such that the carbon fiber spun yarn fabric after carbonization has little misalignment at the time of cutting,
Moreover, a plain weave form having good shaping properties is preferable.

This oxidized fiber spun yarn woven fabric has a thickness of 0.5 to 2.0 m with respect to the carbon fiber spun yarn woven fabric after carbonization.
m, the basis weight is 70 to 250 g / m ² , and the porosity is preferably 5% or less.

In order to make the carbon fiber spun yarn fabric after carbonization have the above-mentioned physical properties, in the weaving of the oxidized fiber spun yarn, the number of spun yarns in the oxidized fiber spun yarn fabric is 4 to 24 / c.
It is preferably m.

(B: Oxidized fiber filament woven fabric) (b-1: Intermingle treatment) A predetermined number of oxidized fibers (single fiber filaments) are intermingled to obtain an oxidized fiber filament bundle.

The intermingling treatment is a fiber entanglement treatment, in which a bundle of monofilament filaments is continuously passed through a nozzle, and pressurized air (0.1 to 1 MPa) is applied from a direction perpendicular to the passing direction. It is a process of applying and intertwining the single fibers.

The number of monofilament filaments in the filament bundle obtained by the intermingle treatment is 100 to 5
0000 pieces / bundle is preferable.

When the number of monofilament filaments in the filament bundle is less than 100 filaments / bundle, the total strength of the filament bundle is low and the fabric processability is deteriorated, which is not preferable.

When the number of monofilament filaments in the filament bundle exceeds 50,000 filaments / bundle, flattening of the filament bundle and flattening of the monofilament become difficult during the compression treatment, which is not preferable.

The intermingle treatment improves the convergence of the oxidized fiber filaments and improves the fabric processability.
In addition, since the filaments after the fabric processing are partially arranged in the thickness direction, the electrical conductivity in the thickness direction of the carbon fiber fabric after carbonization is improved.

The degree of intermingling (fiber entanglement degree) can be indicated by the tear strength.

In the intermingle treatment of the oxidized fiber filament, the tear strength is preferably 5 to 50 g.

When the tear strength in the intermingle treatment is less than 5 g, the filament bundles have a low convergence when the fabric is processed, scattering of single fibers and breaks of the filament bundles occur, and the fabric processability deteriorates, which is not preferable.

When the tear strength in the intermingle treatment exceeds 50 g, the filament bundles have too high a convergence during compression processing, and it is difficult to flatten the filament bundles and flatten the single fibers during the compression treatment. It is not preferable because a thin fabric cannot be obtained.

(B-2: Compression treatment, weaving) The compression treatment and weaving of the oxidized fiber filament bundle obtained by the above intermingle treatment can be performed by the same method and conditions as those for the spun yarn woven fabric described above.

(Carbonization) The oxidized fiber spun yarn woven fabric or oxidized fiber filament woven fabric which has been compressed and woven is heated in an inert gas atmosphere to be continuously carbonized. Nitrogen, argon, helium or the like can be used as the inert gas.

The carbonization temperature is preferably 1300 to 2500 ° C. When the carbonization temperature is lower than 1300 ° C, the electric resistance value increases, which is not preferable. Carbonization temperature is 250
When the temperature is higher than 0 ° C., the electric resistance value decreases and becomes stable, but the strength of the carbon fiber woven fabric decreases and there are problems such as generation of carbon fine powder, which is not preferable.

[0074]

EXAMPLES The present invention will be described in detail with reference to the following examples and comparative examples.

Oxidized fiber spun yarn woven fabrics, oxidized fiber filament woven fabrics, carbon fiber spun yarn woven fabrics, carbon fiber filament woven fabrics, etc. were produced under the conditions of the following examples and comparative examples, and the obtained oxidized fiber spun yarn woven fabrics and oxidized fibers were obtained. Various physical properties of the filament woven fabric, the carbon fiber spun yarn woven fabric, the carbon fiber filament woven fabric and the like were measured by the following methods.

Flatness of monofilament: Electron micrograph of cross section of monofilament constituting spun yarn or filament bundle (magnification: 5
The minimum diameter and the maximum diameter of the fiber were measured from (000 times) and calculated by the following formula. Flatness of single fiber = L ₂ / L ₁ L ₁ : Maximum diameter in single fiber cross section L ₂ : Minimum diameter in single fiber cross section Degree of intermingling of filament bundle (fiber entanglement degree); Tear strength: Cross section of filament bundle Of the filament bundle was divided into two in the length direction of the filament bundle over about 10 cm. A thin tape such as cellophane tape is attached to each of the two divided yarns from the tip by about 5 cm, and this is attached to the chuck part of the Tensilon tensile tester, and the pulling speed is 200 mm / min, the pulling distance is 30 mm, and the chuck interval is 10 cm. Torn. The tear strength (F) was determined by the following formula from the obtained average strength (F _f ) and the mass (F _t ) of the yarn on one side after tearing. F = F _f −F _t Thickness: 200 g load (2.8 kP
The thickness at time a) was measured.

Specific gravity: Archimedes method (solvent: acetone)
It was measured by.

Fiber performance: Dry strength and dry elongation are JIS L 1
015.

Basis weight: Calculated from the mass per unit area and the thickness measured under the above conditions.

Oxygen bond amount: The oxygen content was measured with an elemental analyzer (CHNO coder), and this was used as the oxygen bond amount (a measure of the degree of oxidation).

X-ray crystal size: 2 in wide-angle X-ray diffraction measurement
It was calculated from the half-width of the peak of θ and the Scherrer's formula below. X-ray crystal size (nm) = (k × λ) / β × cos θ k: device constant 0.90 λ: X-ray wavelength 0.154 nm β: 2θ = 26.0 ° Specific resistance value: Two 50 mm squares (thickness 10 m
m) gold-plated electrode on both sides of carbon fiber fabric with pressure 1
It is sandwiched by MPa, the electric resistance value (R) between both electrodes is measured,
It was calculated from the thickness (T) and the contact area (S) by the following formula. Electrical conductivity (specific resistance value: Ωcm) = (R × S) / T Porosity: 1.5 × 10 ^{4 to} 2.5 × 10 ⁴ Place a woven fabric on a light source with a magnification of 100 times from the top. microscope photography, the area of the image obtained by image analysis, the total area of the measurement target fabric (a ₁₎ and the transmitted light portion (absence of the spun yarn) (a ₂₎
Ask for. The gap degree was calculated from these values by the following formula. Porosity (%) = (A ₂ / A ₁ ) × 100 Resin exudation state: Polyvinyl alcohol (PVA:
Using an aqueous solution with a molecular weight of 2000) (viscosity 10000 mP · S),
20 to 20 on one side (upper surface) of 20 cm square carbon fiber woven fabric
After uniformly applying the coating amount in the range of 100 to 150 g / m ² at a temperature of 8 ° C., observing the exudation state of the resin on the opposite surface (back surface) after leaving it at 25 ° C. for 1 hour, and magnifying at 25 times. After the micrograph was taken, the total area of the exuded portion with respect to the total area of the back surface was measured by image processing and calculated by the following formula. Exudation rate% = (exuded area of resin / total area in the direction)
× 100 Example 1 Fineness 2.5 dtex, specific gravity 1.33, crimp number 3.8
/ Cm, crimp rate 11%, dry strength 2.7g / dte
x, a dry elongation of 25%, an average cut length of 51 mm, spun polyacrylonitrile (PAN) -based oxidized fiber staple,
A 35th count twine (spun yarn) having an upper twist of 250 turns / m and a lower twist of 450 turns / m was obtained.

The obtained spun yarn was compressed with a metal heating roller under conditions of a temperature of 250 ° C. and a pressure of 25 MPa to flatten the monofilament. Using the spun yarn after the flattening treatment, the weaving density in both warp and weft is 14 yarns / c
m plain weave (oxidized fiber spun yarn woven fabric) was produced. The obtained oxidized fiber spun yarn woven fabric had a basis weight of 245 g / m ² and a thickness of 0.45 mm.

Further, this oxidized fiber spun yarn fabric was fired at a firing temperature of 1900 ° C. in a nitrogen gas atmosphere to obtain a carbon fiber spun yarn fabric. Table 1 shows the physical properties of the obtained carbon fiber spun yarn woven fabric.
Shown in.

As shown in Table 1, the physical properties of the obtained carbon fiber spun yarn woven fabric were excellent.

Example 2 The flattening treatment of monofilaments was performed by compressing the 35th count twine yarn (spun yarn) obtained in Example 1 with a metal heating roller under the conditions of a temperature of 250 ° C. and a pressure of 15 MPa. It was
Using the spun yarn after the flattening treatment, a plain weave (oxidized fiber spun yarn woven fabric) having a weaving density of 15 warps / cm was prepared. The weight of the obtained oxidized fiber spun yarn fabric is 250 g /
m ² and the thickness was 0.48 mm.

Further, this oxidized fiber spun yarn fabric was fired at a firing temperature of 1900 ° C. in a nitrogen gas atmosphere to obtain a carbon fiber spun yarn fabric. Table 1 shows the physical properties of the obtained carbon fiber spun yarn woven fabric.
Shown in.

As shown in Table 1, the physical properties of the obtained carbon fiber spun yarn woven fabric were excellent.

Comparative Example 1 The single-filament flattening treatment was carried out by compressing the 35th count twine yarn (spun yarn) obtained in Example 1 with a metal heating roller under the conditions of a temperature of 350 ° C. and a pressure of 75 MPa. It was
Using the spun yarn after the flattening treatment, a plain weave (oxidized fiber spun yarn woven fabric) having a weaving density of 16 warp / cm was prepared. The basis weight of the obtained oxidized fiber spun yarn fabric is 244 g /
m ² and the thickness was 0.44 mm.

Further, this oxidized fiber spun yarn woven fabric was fired at a firing temperature of 1900 ° C. in a nitrogen gas atmosphere. However, the strength of the carbon fiber spun yarn fabric during firing was significantly reduced, and the fabric was cut during firing.

[0090]

[Table 1]

Comparative Example 2 The single-filament flattening treatment was carried out by compressing the 35th count twine yarn (spun yarn) obtained in Example 1 with a metal heating roller under the conditions of temperature 120 ° C. and pressure 75 MPa. It was
Using the spun yarn after the flattening treatment, a plain weave (oxidized fiber spun yarn woven fabric) having a weave density of 18 warps / cm was prepared. The basis weight of the obtained oxidized fiber spun yarn fabric is 256 g /
m ² and the thickness was 0.81 mm.

Further, this oxidized fiber spun yarn fabric was fired at a firing temperature of 1900 ° C. in a nitrogen gas atmosphere to obtain a carbon fiber spun yarn fabric. Table 2 shows the physical properties of the obtained carbon fiber spun yarn woven fabric.
Shown in.

As shown in Table 2, the obtained carbon fiber spun yarn woven fabric had a large amount of resin exudation of 2% by mass, which was unsuitable.

Example 3 The No. 35 yarn (spun yarn) obtained in Example 1 was treated by immersing it in an aqueous solution of carboxymethyl cellulose and adding 2% by mass of carboxymethyl cellulose to the metal heated roller. The flattening treatment of the single fiber was performed by performing compression treatment under the conditions of a temperature of 200 ° C. and a pressure of 35 MPa. Using the spun yarn after the flattening treatment, a plain weave (oxidized fiber spun yarn woven fabric) having a weaving density of 15 warps / cm was prepared. The weight of the obtained oxidized fiber spun yarn fabric is 252.
It was g / m ² and had a thickness of 0.50 mm.

Further, this oxidized fiber spun yarn fabric was fired at a firing temperature of 1900 ° C. in a nitrogen gas atmosphere to obtain a carbon fiber spun yarn fabric. Table 2 shows the physical properties of the obtained carbon fiber spun yarn woven fabric.
Shown in.

As shown in Table 2, the physical properties of the obtained carbon fiber spun yarn woven fabric were excellent.

Comparative Example 3 Fineness 2.5 dtex, specific gravity 1.44, crimp number 3.7
/ Cm, crimp rate 10%, dry strength 2.3 g / dte
x, a dry elongation of 21%, an average cut length of 51 mm was spun on a polyacrylonitrile (PAN) -based oxidized fiber staple,
A 35th count twine (spun yarn) having an upper twist of 250 turns / m and a lower twist of 550 turns / m was obtained.

The obtained spun yarn is treated by immersing it in an aqueous solution of carboxymethyl cellulose, and after containing 2% by mass of carboxymethyl cellulose, it is compressed with a metal heating roller under the conditions of a temperature of 200 ° C. and a pressure of 3 MPa. Thus, the flattening treatment of the single fiber was performed. Using the flattened spun yarn, weaving density of 17 yarns in both warp and weft
cm plain weave (oxidized fiber spun yarn fabric) was prepared. The resulting oxidized fiber spun yarn woven fabric had a basis weight of 260 g / m ² and a thickness of 0.74 mm.

Further, it was fired in a nitrogen gas atmosphere at a firing temperature of 1900 ° C. to obtain a carbon fiber spun yarn woven fabric. Table 2 shows the physical properties of the obtained carbon fiber spun yarn woven fabric.

As shown in Table 2, the obtained carbon fiber spun yarn woven fabric had a large amount of resin exudation of 3% by mass, which was unsuitable.

[0101]

[Table 2]

Example 4 Fineness 2.3 dtex, specific gravity 1.38, single fiber number 1000
A filament bundle of polyacrylonitrile (PAN) -based oxidized fibers is blown with pressurized air at a pressure of 0.1 MPa in a direction perpendicular to the traveling direction of the filament bundle to continuously entangle single fibers (intermingle treatment). And then
A filament bundle having a tear strength of 15 g was obtained.

The filament bundle after the intermingle treatment was heated with a metal heating roller at a temperature of 200 ° C. and a pressure of 35.
The flattening treatment of the single fiber was performed by performing the compression treatment under the condition of MPa. Using the spun yarn after this flattening treatment,
A plain weave (oxidized fiber spun yarn woven fabric) having a weaving density of 7 yarns / cm was prepared for both warp and weft. The obtained oxidized fiber spun yarn fabric had a basis weight of 215 g / m ² and a thickness of 0.65 mm.

Further, this oxidized fiber spun yarn fabric was fired at a firing temperature of 1900 ° C. in a nitrogen gas atmosphere to obtain a carbon fiber filament fabric. Table 3 shows the physical properties of the obtained carbon fiber filament woven fabric.

As shown in Table 3, the physical properties of the obtained carbon fiber filament woven fabric were excellent.

Example 5 Fineness 2.3 dtex, specific gravity 1.38, single fiber number 1000
The filament bundle of polyacrylonitrile (PAN) -based oxidized fibers is blown with pressurized air at a pressure of 0.3 MPa in a direction perpendicular to the traveling direction of the filament bundle to continuously entangle the single fibers (intermingle treatment). And then
A filament bundle having a tear strength of 35 g was obtained.

The filament bundle after the intermingle treatment was dipped in an aqueous solution of polyvinyl alcohol to be treated so that 1.0% by mass of polyvinyl alcohol was adhered and contained therein, and the temperature was 220 ° C. and the pressure was 35 M with a metal heating roller.
The flattening treatment of the single fiber was performed by performing the compression treatment under the condition of Pa. Using the spun yarn after this flattening treatment,
A plain weave (oxidized fiber spun yarn woven fabric) having a weaving density of 7 yarns / cm was prepared for both warp and weft. The basis weight of the obtained oxidized fiber spun yarn woven fabric was 217 g / m ² , and the thickness was 0.64 mm.

Further, this oxidized fiber spun yarn fabric was fired at a firing temperature of 1900 ° C. in a nitrogen gas atmosphere to obtain a carbon fiber filament fabric. Table 3 shows the physical properties of the obtained carbon fiber filament woven fabric.

As shown in Table 3, the physical properties of the obtained carbon fiber filament woven fabric were excellent.

Comparative Example 4 Fineness 2.3 dtex, specific gravity 1.38, single fiber number 1000
A filament bundle of polyacrylonitrile (PAN) -based oxidized fibers (without entanglement treatment, tear strength 3 g) is dipped in an aqueous polyvinyl alcohol solution to be treated, and 1.0% by mass of polyvinyl alcohol is adhered and contained therein, and then a metal heating roller. A plain weave (oxidized fiber spun yarn woven fabric) having a weaving density of 8 warps / cm was produced using this spun yarn without performing the flattening treatment of the single fiber in 1. The obtained oxidized fiber spun yarn fabric has a basis weight of 235 g / m ² and a thickness of 0.87.
It was mm.

Further, this oxidized fiber spun yarn fabric was fired at a firing temperature of 1900 ° C. in a nitrogen gas atmosphere to obtain a carbon fiber filament fabric. Table 3 shows the physical properties of the obtained carbon fiber spun yarn woven fabric.

As shown in Table 3, the obtained carbon fiber filament woven fabric was unsuitable because the resin exudation was as large as 7% by mass.

[0113]

[Table 3]

[0114]

The carbon fiber woven fabric of the present invention is a carbon fiber woven fabric composed of spun yarns or filament bundles, and is a thin woven fabric since the single fibers constituting the spun yarns or filament bundles have a flat cross section. Even if it is present, it is a carbon fiber woven fabric in which the treating agent does not seep to the non-treated surface in the one-side treatment.

Further, according to the method for producing a carbon fiber structure of the present invention, the polyacrylonitrile-based oxidized fiber is subjected to a spinning process or an intermingling process to obtain a spun yarn or a filament bundle, and the obtained spun yarn or The filament bundle
Since compression treatment is performed under predetermined conditions, and then the fabric is processed and then carbonized, it is possible to obtain a carbon fiber fabric in which the treatment agent does not ooze out to the non-treated surface in the one-side treatment.

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Claims (5)

[Claims] 1. A spun yarn or filament bundle containing at least polyacrylonitrile oxide monofilament having a flat cross section. 2. A carbon fiber woven fabric comprising spun yarns or filament bundles, wherein the single fibers constituting the spun yarns or filament bundles have a flat cross-sectional shape. 3. The flatness (L ₂ / L ₁ ) of the monofilament, which is represented by the maximum diameter (L ₁ ) of the cross section of the monofilament and the minimum diameter (L ₂ ) of the cross section of the monofilament, is 0.2 to. The carbon fiber woven fabric according to claim 2, which is 0.7. 4. A spun yarn or filament bundle is obtained by spinning or intermingling polyacrylonitrile oxide fiber, and the spun yarn or filament bundle is obtained at a temperature of 150 to 400 ° C. and a pressure of 5 to 50 MPa. A method for producing a spun yarn or filament bundle containing at least polyacrylonitrile oxide monofilament having a flat cross-sectional shape, which is characterized in that compression treatment is performed. 5. A spun yarn or filament bundle is obtained by spinning or intermingling polyacrylonitrile oxide fiber, and the spun yarn or filament bundle is obtained at a temperature of 150 to 400 ° C. and a pressure of 5 to 50 MPa. A method for producing a carbon fiber woven fabric, which comprises subjecting the woven fabric to compression treatment, then processing the woven fabric, and then carbonizing.