JP5873248B2 - Carbon fiber spun yarn fabric, carbon fiber precursor spun yarn fabric, and method for producing carbon fiber spun yarn fabric - Google Patents

Description

  The present invention relates to a carbon fiber spun yarn fabric, a carbon fiber precursor spun yarn fabric, and a method for producing a carbon fiber spun yarn fabric.

  A fuel cell, in particular a polymer electrolyte fuel cell, is a device that generates power by reacting a fuel gas such as hydrogen with an oxidizing gas such as oxygen. Such a fuel cell generally has a structure in which a catalyst layer, a gas diffusion electrode, and a separator are sequentially arranged on both sides of an exchange membrane.

  The gas diffusion electrode of the fuel cell has a function of diffusing fuel gas or oxidizing gas and supplying it to the catalyst layer. As a base material for a gas diffusion electrode of a fuel cell, generally, a carbon fiber spun yarn woven fabric, which is a conductive sheet-like carbon fiber, porous paper, felt, or the like is used.

  When a carbon fiber spun yarn fabric is used as the gas diffusion electrode base material, the catalyst layer is formed by applying a catalyst and a carbon powder carrying the catalyst onto one surface of the carbon fiber spun yarn fabric. . Therefore, the carbon fiber spun yarn fabric needs strength to support the catalyst layer.

  The gas diffusion electrode substrate also has a function of discharging water generated in the catalyst layer by the reaction of the fuel gas and the oxidizing gas to the separator side. Therefore, the carbon fiber spun yarn fabric used as the gas diffusion electrode substrate is required to have sufficient air permeability and drainage in addition to low electrical resistance. Therefore, it is desired to reduce the thickness of the carbon fiber spun yarn fabric from the viewpoint of ensuring air permeability and drainage while ensuring a predetermined strength.

  In recent years, the demand for fuel cells for automobiles has increased. Therefore, from the viewpoint of realizing the manufacture of a small fuel cell that can be used in applications where installation space is limited, such as automobiles, it is desirable to manufacture a carbon fiber spun yarn fabric with a small thickness that contributes to miniaturization of the fuel cell. ing.

  As a method for producing a carbon fiber spun yarn fabric having a small thickness, weaving using a thin carbon fiber spun yarn has been proposed. However, in this case, thread breakage may occur and weaving may be difficult.

  As another method, Patent Document 1 proposes a carbon fiber spun yarn fabric using a thermoplastic fiber mixed oxidized fiber as a raw material using a spun yarn obtained by mixing and spinning oxidized fiber and thermoplastic fiber. In this proposal, the thickness of the carbon fiber spun yarn fabric can be reduced to 0.14 to 0.6 mm by using a calendar process in combination. However, the strength of the carbon fiber spun yarn fabric after carbonization is reduced due to fiber damage due to calendering. Moreover, the rigidity after baking becomes large and the bending resistance becomes large. That is, a carbon fiber spun yarn fabric having high flexibility and small thickness cannot be produced.

  Patent Document 2 proposes a carbonaceous fiber woven fabric composed of carbonaceous fiber yarns having a major axis that is twice or more the minor axis. In the production of a carbon fiber woven fabric using the carbon fiber yarn, press treatment is considered essential. However, this press treatment damages the fiber and decreases the strength after carbonization. In addition, since the carbon fiber woven fabric binds the fibers with the binder carbide, the elongation becomes low and becomes brittle. As a result, there is a concern that the fiber is likely to break during the water-repellent treatment during the production of the gas diffusion electrode and the catalyst coating treatment.

JP 2007-39843 A JP 2004-100102 A

  An object of the present invention is to provide a carbon fiber spun yarn fabric having a small thickness, a method for producing the carbon fiber spun yarn fabric, and a carbon fiber precursor spun yarn fabric used as a raw material for the carbon fiber spun yarn fabric.

  The present inventor has been diligently studying the above problems, and at the stage of manufacturing the carbon fiber precursor spun yarn fabric, the carbon fiber precursor spun yarn is given a predetermined thickness for spinning and weaving processes. After weaving a carbon fiber precursor spun yarn fabric that retains the required strength, a carbon fiber spinning material with a small thickness is obtained through a process of reducing or eliminating the components contained in the carbon fiber precursor spun yarn. The present inventors have found that a yarn woven fabric can be produced and have completed the present invention.

The present invention is a carbon fiber spun yarn fabric having a thickness of 50 to 300 μm, a basis weight of 10 to 80 g / m ² , a bending resistance of 10 mNcm or less, an electric resistance value of 200 mΩ / cm ² or less, and a porosity of 2 to 20%, The carbon fiber spun yarn constituting the carbon fiber spun yarn fabric has a carbon fiber spun yarn selected from the group consisting of 1/50 to 1/200 Nm single yarn and 2/100 to 2/400 Nm twin yarn. It is a woven fabric.

  The carbon fiber spun yarn fabric of the present invention is obtained by carbonizing a carbon fiber precursor spun yarn fabric under predetermined conditions. The carbon fiber precursor spun yarn, which is at least the weft of the carbon fiber precursor spun yarn fabric, is made from a carbon fiber precursor fiber and an extinct fiber mixed or twisted with the carbon fiber precursor fiber. The carbon fiber precursor spun yarn containing the disappearing fiber.

  The vanishing fiber comprises a component that can disappear from the carbon fiber precursor spun yarn after weaving the carbon fiber precursor spun yarn fabric. As the extinct fiber, water-soluble fiber that elutes in water at 100 ° C. or less and low residual carbon fiber are preferable. The low residual carbon fiber is preferably non-melted under firing conditions of 1300 to 2300 ° C. in an inert gas atmosphere, and the residue after firing is preferably 10% by mass or less.

  The carbon fiber precursor fiber used in the present invention is a carbon fiber precursor staple, the water-soluble fiber blended with the carbon fiber precursor staple is a water-soluble fiber staple, and the carbon fiber precursor spinning containing the disappearing fiber. The blend ratio of the water-soluble fiber staple in the yarn is preferably 10 to 50% by mass.

  The carbon fiber precursor fiber used in the present invention is a carbon fiber precursor spun yarn or carbon fiber precursor strand, and the water-soluble fiber to be twisted with the carbon fiber precursor spun yarn or carbon fiber precursor strand is It is preferably a water-soluble fiber spun yarn or a water-soluble fiber strand.

  The carbon fiber precursor fiber used in the present invention is a carbon fiber precursor staple, and the low residual carbon fiber blended with the carbon fiber precursor staple is a low residual carbon fiber staple, and the carbon fiber precursor containing the disappearing fiber. The blend ratio of the low residual carbon fiber staple in the body spun yarn is preferably 10 to 50% by mass.

  The carbon fiber precursor fiber used in the present invention is a carbon fiber precursor spun yarn or carbon fiber precursor strand, and the low residual carbon fiber to be twisted with the carbon fiber precursor spun yarn or carbon fiber precursor strand is A low residual carbon fiber spun yarn or a low residual carbon fiber strand is preferable.

The present invention weaves a carbon fiber precursor spun yarn fabric using at least the carbon fiber precursor spun yarn containing the water-soluble fiber as a weft, and the carbon fiber precursor spun yarn fabric is immersed in water at 100 ° C. or less. The carbon fiber precursor spun yarn fabric is immersed and refined to dissolve and disappear only the water-soluble fiber from the carbon fiber precursor spun yarn fabric, and the carbon fiber precursor spun yarn fabric from which the water-soluble fiber has disappeared is treated with an inert gas atmosphere. Below, it includes a method for producing a carbon fiber spun yarn woven fabric, in which a carbon fiber spun yarn fabric is produced by firing at 1300 to 2300 ° C. for 0.5 to 10 minutes and carbonizing. The carbon fiber spun yarn fabric produced by the method for producing the carbon fiber spun yarn fabric has a thickness of 50 to 300 μm, a basis weight of 10 to 80 g / m ² , a bending resistance of 10 mNcm or less, an electric resistance value of 200 mΩ / cm ² or less, and a mesh space. The degree is 2 to 20%. Further, the metric count of the carbon fiber spun yarn constituting the carbon fiber spun yarn fabric is selected from the group consisting of 1/50 to 1/200 Nm single yarn and 2/100 to 2/400 Nm twin yarn. .

The present invention uses a carbon fiber precursor spun yarn containing the above-mentioned low residual carbon fiber as at least a weft to weave a carbon fiber precursor spun yarn fabric, and the carbon fiber precursor spun yarn fabric is treated with an inert gas. It is fired at 1300-2300 ° C. for 0.5-10 minutes in an atmosphere to reduce the low residual carbon fiber from the carbon fiber precursor spun yarn fabric, and carbonize the carbon fiber precursor spun yarn fabric to carbonize it. It includes a method for producing a carbon fiber spun yarn fabric, which produces a fiber spun yarn fabric. The carbon fiber spun yarn fabric produced by the method for producing the carbon fiber spun yarn fabric has a thickness of 50 to 300 μm, a basis weight of 10 to 80 g / m ² , a bending resistance of 10 mNcm or less, an electric resistance value of 200 mΩ / cm ² or less, and a mesh space. The degree is 2 to 20%. Further, the metric count of the carbon fiber spun yarn constituting the carbon fiber spun yarn fabric is selected from the group consisting of 1/50 to 1/200 Nm single yarn and 2/100 to 2/400 Nm twin yarn. .

  The present invention includes a carbon fiber spun yarn fabric used as an electrode material for a gas diffusion electrode of a fuel cell, a gas diffusion electrode for producing caustic soda, and a method for producing the carbon fiber spun yarn fabric.

  The carbon fiber spun yarn fabric of the present invention has a small thickness and a high degree of gap. Therefore, by using the carbon fiber spun yarn fabric of the present invention as a gas diffusion electrode of a fuel cell, the fuel cell can be miniaturized and a stack with a high degree of design freedom can be provided.

  Hereinafter, the present invention will be described in detail.

  The thickness of the carbon fiber spun yarn fabric of the present invention is 50 to 300 μm, and more preferably 100 to 200 μm. If it is less than 50 μm, the strength required for processing the gas diffusion electrode is insufficient. If it exceeds 300 μm, it is difficult to reduce the size of the fuel cell, which is not preferable.

The basis weight of the carbon fiber spun yarn fabric of the present invention is 10 to 80 g / m ² . When it is less than 10 g / m ² , the strength of the carbon fiber spun yarn fabric is low, so it cannot be used as a gas diffusion electrode. When it exceeds 80 g / m ² , a carbon fiber spun yarn fabric having a desired thickness cannot be obtained.

  The bending resistance of the carbon fiber spun yarn fabric of the present invention is 10 mNcm or less. When it exceeds 10 mNcm, it cannot be wound around a paper tube having an outer diameter of 2.54 cm (1 inch) or less, or a crease may occur when it is wound.

The electric resistance value of the carbon fiber spun yarn fabric of the present invention is 200 mΩ / cm ² or less. When it exceeds 200 mΩ / cm ² , when used as a gas diffusion electrode of a fuel cell, the electric resistance value is too large and a good fuel cell output cannot be obtained. The lower limit of the electric resistance value is not particularly limited, but is generally 40 mΩ / cm ² or more.

  The carbon fiber spun yarn fabric of the present invention has a gap degree of 2 to 20%, more preferably 2.5 to 15%. In the case of less than 2%, the degree of gap is too small, and the generated water generated by the cell reaction of the fuel cell cannot be drained sufficiently. If it exceeds 20%, when the catalyst electrode layer is applied, the catalyst component oozes out from the gap portion, and the gas diffusibility in the surface direction is lowered.

  The carbon fiber spun yarn constituting the carbon fiber spun yarn fabric of the present invention may be a single yarn or a twin yarn.

  In the case of a single yarn, the metric count is 1/50 to 1/200 Nm, and preferably 1/60 to 1/100 Nm. In the case of twin yarn, the metric count is 2/100 to 2/400 Nm, and preferably 2/120 to 2/200 Nm.

  In the case of single yarn and twin yarn, if the metric count is thicker than the predetermined range, a carbon fiber spun yarn fabric having a predetermined thickness cannot be obtained. In the case of a metric count thinner than a predetermined range, since the strength is low, cutting frequently occurs during spinning and weaving. That is, productivity is poor and is not preferable.

  In the present invention, the single fiber diameter of the carbon fiber constituting the carbon fiber spun yarn fabric is preferably 4 to 20 μm, and more preferably 5 to 15 μm. When the diameter is less than 4 μm, the single fiber diameter is too thin, and the fiber is frequently cut during processing. Furthermore, there is a possibility that the carbon fiber may fall off from the carbon fiber spun yarn fabric. When it exceeds 20 μm, the contact area between the fibers decreases, and the electric resistance value of the carbon fiber spun yarn fabric increases. As a result, there is a problem in that the output of a fuel cell manufactured using this decreases, the fiber strength decreases during carbonization, and a large amount of carbon fiber fine powder is generated.

  The carbon content of the carbon fiber spun yarn fabric is preferably 95% by mass or more. When the amount is less than 95% by mass, there is a problem that the electric resistance value is large, the fuel cell performance is deteriorated, and the oxidation deterioration is caused in a strongly acidic atmosphere during the reaction.

  The carbon fiber precursor spun yarn fabric of the present invention is woven using at least a weavable fiber-containing carbon fiber precursor spun yarn as a weft. The vanishing fiber refers to a component that can disappear from the carbon fiber precursor spun yarn after weaving the carbon fiber precursor spun yarn fabric, and includes water-soluble fibers and low residual carbon fibers. The water-soluble fiber refers to a fiber that is eluted from the carbon fiber precursor spun yarn by a water washing treatment. The low residual carbon fiber means a fiber whose content in the carbon fiber precursor spun yarn is reduced by the carbonization treatment. Hereinafter, the water-soluble fiber and the low residual carbon fiber may be collectively referred to as “disappearing fiber”.

  The vanishable fiber-containing carbon fiber precursor spun yarn is spun at a thickness having strength necessary for weaving the carbon fiber precursor spun yarn fabric.

  The carbon fiber precursor spun yarn fabric woven using the vanishing fiber-containing carbon fiber precursor spun yarn has a thickness derived from the thickness of the vanishing fiber-containing carbon fiber precursor spun yarn. However, the evanescent fiber contained in the carbon fiber precursor spun yarn is a component that can be eliminated or reduced by washing with water or heat treatment. Therefore, when the carbon fiber precursor spun yarn fabric of the present invention is washed with water or carbonized, the carbon fiber spun yarn constituting the carbon fiber spun yarn fabric obtained by these treatments is a carbon containing a disappearing fiber. Thinner than the fiber precursor spun yarn. Therefore, even if there is a thickness at the stage of carbon fiber precursor spun yarn fabric, the thickness of the carbon fiber spun yarn fabric obtained from the carbon fiber precursor spun yarn fabric becomes small.

  That is, the present invention uses the carbon fiber spun yarn containing the extinction fiber as at least the weft of the carbon fiber precursor spun yarn fabric, and thereby the thickness of the carbon fiber spun yarn constituting the carbon fiber spun yarn fabric finally obtained. Can be adjusted. That is, at the stage of weaving the carbon fiber precursor spun yarn fabric, the carbon fiber precursor spun yarn can be thickened to ensure the strength necessary for weaving the carbon fiber precursor spun yarn. Thereby, the carbon fiber precursor spun yarn fabric can be woven without breaking. After weaving, the carbon fiber precursor spun yarn woven fabric is washed with water or carbonized to reduce or eliminate the disappearing fibers, thereby forming carbon fibers composed of carbon fiber spun yarns of a predetermined metric count. A spun yarn fabric can be obtained. The obtained carbon fiber spun yarn fabric has a small thickness and a high degree of gap.

  Examples of the carbon fiber precursor fiber used in the present invention include oxidized fiber, rayon fiber, and cellulose. An oxidized fiber is a fiber obtained by oxidizing a raw material fiber at 200-400 degreeC in the air. Any conventionally known oxidized fibers such as PAN-based oxidized fibers and pitch-based oxidized fibers using polyacrylonitrile (PAN) -based, pitch-based fibers and the like as raw fibers can be used. From the viewpoint of spinning and weaving, when the carbon fiber precursor fiber is a staple fiber, the fiber length is preferably 30 to 75 mm. The fineness is preferably 0.5 to 3.4 dtex. The number of crimps is preferably 100 to 800 pieces / m. The crimp rate is preferably 4 to 20%.

  As the spun yarn using carbon fiber precursor fiber as a raw material, the above-mentioned staple fiber is used, and a constant length spun yarn produced at a lower twist number of 150 to 1200 times / m and an upper twist number of 100 to 800 times / m, And weaving spun yarn produced by tow spinning and the like.

  The vanishing fiber is a component contained in the carbon fiber precursor spun yarn in addition to the water-soluble fiber and low residual carbon fiber, and after weaving the carbon fiber precursor spun yarn fabric, the carbon fiber precursor spun yarn Any component that can be eliminated in the process of obtaining a carbon fiber spun yarn fabric from the fabric can be used without particular limitation.

  From the viewpoint of obtaining a good blended state or a twisted state, when the evanescent fiber is a staple fiber, the fiber length is preferably 30 to 75 mm. The fineness is preferably 0.5 to 3.4 dtex. The number of crimps is preferably 100 to 800 pieces / m. The crimp rate is preferably 4 to 20%. As for the number of twists, the number of upper twists is preferably 100 to 800 times / m, and the number of lower twists is preferably 150 to 1200 times / m.

  As the water-soluble fiber, for example, polyvinyl alcohol (PVA), which is eluted in water at 100 ° C. or lower, is preferable from the viewpoint of processability.

  The low residual carbon fiber is a non-melting cellulose, rayon having a residual carbon ratio of not more than 10% by mass of a residue after heat treatment at 1300 to 2300 ° C. in an inert gas atmosphere and not causing sticking during the heat treatment. Phenol and the like are preferable. The residual carbon ratio of the low residual carbon fiber is more preferably 10% by mass or less, and further preferably 5% by mass or less, after nitrogen and heat treatment at 1300 ° C.

  In the carbon fiber precursor spun yarn fabric of the present invention, at least the disappearing fiber-containing carbon fiber precursor spun yarn that becomes the weft is obtained by blending or twisting the carbon fiber precursor fiber and the disappearing fiber. As the vanishable fiber-containing carbon fiber precursor spun yarn, a water-soluble fiber-containing carbon fiber precursor spun yarn obtained by mixing the carbon fiber precursor staple and the water-soluble fiber staple, or the carbon fiber precursor staple and the low residual carbon. A carbon fiber precursor spun yarn containing a low residual carbon fiber blended with a fiber staple can be mentioned.

  The blending ratio of the water-soluble fiber staple and the low carbon residue fiber staple in the vanishing fiber-containing carbon fiber precursor spun yarn is preferably 10 to 50% by mass, and more preferably 20 to 40% by mass. When the blending ratio is less than 10% by mass, the thickness of the finally obtained carbon fiber spun yarn fabric may not be sufficiently reduced. When the blending ratio exceeds 50% by mass, the strength required for passing through the process cannot be maintained because the strength is too low when the vanishable fiber-containing carbon fiber precursor spun yarn fabric is washed with water or carbonized. As a result, the carbon fiber precursor spun yarn fabric may break and the carbon fiber spun yarn fabric may not be manufactured.

  Depending on the above blend ratio, the metric count of the extinct fiber-containing carbon fiber precursor spun yarn is selected from a predetermined group. The predetermined group of metric counts consists of a single yarn of 1/20 to 1/100 Nm and a double yarn of 2/40 to 2/200 Nm.

  Other examples of vanishing fiber-containing carbon fiber precursor spun yarn include water-soluble fiber containing twisted carbon fiber precursor spun yarn or carbon fiber precursor strand and water-soluble fiber spun yarn or water-soluble fiber strand There is a carbon fiber precursor spun yarn. Moreover, the carbon fiber precursor spun yarn or carbon fiber strand and the low carbon residue fiber spun yarn or the low carbon residue fiber strand are low twist carbon fiber-containing carbon fiber precursor spun yarn.

  The carbon fiber precursor spun yarn woven fabric of the present invention can be obtained by weaving the extinct fiber-containing carbon fiber precursor spun yarn using at least the weft. The weaving form is not particularly limited as long as it is a known weaving form such as plain weave or twill weave. The number of driving is preferably 10/10 / cm to 50/50 / cm.

  When the carbon fiber spun yarn fabric manufactured using the carbon fiber precursor spun yarn fabric containing the vanishing fiber of the present invention as a raw material is a low residual carbon fiber in which the vanishing fiber is dissipated and disappears by heat treatment Can be obtained by carbonizing a carbon fiber precursor spun yarn fabric containing evanescent fibers. When the disappearing fiber is a water-soluble fiber, it is necessary to perform a water washing treatment before the carbonization treatment. By performing the carbonization treatment or the water washing treatment, the disappearing fibers can be eliminated from the vanishing fiber-containing carbon fiber spun yarn, or the low residual carbon fibers can be reduced. As a result, a carbon fiber spun yarn woven fabric composed of carbon fiber spun yarn having a predetermined metric count, having a small thickness and a high degree of gap can be obtained.

  The method for producing the carbon fiber spun yarn fabric of the present invention will be described below.

  The carbon fiber precursor spun yarn and the disappearing fiber are blended within the above blending ratio range or are twisted to produce a disappearing fiber-containing carbon fiber precursor spun yarn. The spinning method may be a known spinning method and is not particularly limited.

  Carbon fiber precursor-spun yarn fabric in a known weaving form using the produced vanishing fiber-containing carbon fiber precursor spun yarn as the weft and warp, or using the vanishing fiber-containing carbon fiber precursor spun yarn only for the weft Weave. The number of driving is preferably 10/10 / cm to 50/50 / cm. At the time of weaving, the vanishing fiber-containing carbon fiber precursor spun yarn has a predetermined thickness and thus has a strength necessary for weaving. Therefore, the carbon fiber precursor spun yarn fabric does not break at the weaving stage.

  After weaving, if the disappearing fiber is a water-soluble fiber, the carbon fiber precursor spun yarn fabric is refined with water at 100 ° C. or lower for 1 to 20 minutes, and only the water-soluble fiber is removed from the carbon fiber precursor spun yarn fabric. Elute.

  Subsequently, the low residual carbon fiber-containing carbon fiber precursor spun yarn fabric, or the carbon fiber precursor spun yarn fabric from which water-soluble fibers are eluted is 0.5 to 2 at a temperature of 1300 to 2300 ° C. in an inert gas atmosphere. Carbonization treatment is performed by baking for 10 minutes. By performing carbonization under this firing condition, the electric resistance value of the obtained carbon fiber spun yarn fabric can be reduced.

  When the carbonization temperature is less than 1300 ° C., the carbon content of the obtained carbon fiber spun yarn fabric is low, and a carbon fiber spun yarn fabric having a carbon content of 95% by mass or more can be obtained. Can not. In that case, since the electrical conductivity of the carbon fiber spun yarn fabric is lowered, good fuel cell performance cannot be obtained, which is not preferable.

  When the temperature exceeds 2300 ° C., the carbon fiber spun yarn fabric becomes stiff and the strength is lowered. Furthermore, problems such as the generation of fine carbon powder occur, which is not preferable.

  By going through the above-mentioned refining treatment and carbonization treatment, the disappearing fibers contained in the carbon fiber precursor spun yarn fabric can be lost or greatly reduced. Therefore, the carbon fiber spun yarn fabric finally obtained from the vanishable fiber-containing carbon fiber precursor spun yarn fabric of the present invention consists essentially of carbon fibers. The metric count of the carbon fiber spun yarn is selected from the group consisting of 1/50 to 1/200 Nm single yarn and 2/100 to 2/400 Nm twin yarn. Since the diameter of the carbon fiber spun yarn used for the carbon fiber spun yarn fabric is smaller than the diameter of the carbon fiber precursor spun yarn, a carbon fiber spun yarn fabric having a small thickness and a high degree of voids can be produced.

  EXAMPLES Hereinafter, the present invention will be described more specifically with reference to examples, but the present invention is not limited to these examples. In addition, evaluation of operation conditions and measurement of each physical property were based on the following methods.

[Thickness]
With a thickness gauge, a thickness of the carbon fiber spun yarn fabric was measured by applying a load of 6.9 kPa in the thickness direction of the carbon fiber spun yarn fabric.

[Unit weight]
A square carbon fiber spun yarn woven fabric having a side of 10 cm was calculated from a mass value after drying at 120 ° C. for 1 hour.

[Electric resistance value]
A sample of carbon fiber spun yarn fabric with a square of 50 mm on one side is prepared, and this sample of carbon fiber spun yarn fabric is made to contact the whole surface with two gold-plated electrodes of a square (thickness 10 mm) with a side of 50 mm. The electric resistance value in the thickness direction of the carbon fiber spun yarn fabric when the load of 10 kPa is applied in the thickness direction of the carbon fiber spun yarn fabric is measured, and the electric resistance per unit area divided by the electrode area The value was determined.

[Bending softness]
Five carbon fiber spun yarn fabrics were cut out as test pieces with a length of 15 cm and a width of 2 cm along the warp direction. Each test piece was measured for bending resistance according to a method (Method B) described in JIS L 1096, and an average value was calculated.

[Clearance degree]
A test piece of carbon fiber spun yarn fabric was placed on a light source of 1.5 × 10 4 to 2.5 × 10 4 lux, and microscopic images were taken from the top at a magnification of 100 times, and the obtained image was subjected to image analysis. Total area (A ₁₎ and the transmitted light of the measurement target fabric the area of (the absence of the spun yarn) (A ₂₎ determined. From these values, the degree of eye clearance was calculated by the following equation.

Crevice degree (%) = (A ₂ / A ₁ ) × 100

[Metric count of carbon fiber spun yarn]
The warp and weft were pulled out from the carbon fiber spun yarn fabric, and the metric numbers of the warp carbon fiber spun yarn and the weft carbon fiber spun yarn were measured based on JIS L 1096, respectively.

[Examples 1 to 4]
PAN-based oxidized fiber (OPF) [fiber length 51 mm, fineness 1.4 dtex, crimp number 400 pieces / m, crimp rate 10%] and PVA fiber [fiber length 51 mm, fineness 1.4 dtex, crimp number 400 pieces / m, A crimp ratio of 10%] was mixed at the blending ratio shown in Table 1 to produce a PVA fiber-containing carbon fiber precursor spun yarn with a lower twist number of 1000 times / m and an upper twist number of 480 times / m and a metric count of 2/80 Nm. did.

  Using this PVA fiber-containing carbon fiber precursor spun yarn, weaving was performed at a history = 20/20 yarns / cm to produce a PVA fiber-containing carbon fiber precursor spun yarn fabric (Example 1-4). In Example 1-3, PVA fiber-containing carbon fiber precursor spun yarn was used for warp and weft. In Example 4, the PVA fiber-containing carbon fiber precursor spun yarn was used only for the weft, and the warp yarn was a carbon fiber precursor spun yarn containing no PVA fiber.

  The obtained PVA fiber-containing carbon fiber precursor spun yarn fabric was refined with water at 95 ° C. for 20 minutes, and only the PVA fibers were eluted to obtain a carbon fiber precursor spun yarn fabric.

  The obtained carbon fiber precursor spun yarn fabric was carbonized by heat treatment at 1600 ° C. for 5 minutes to obtain a carbon fiber spun yarn fabric.

  Table 1 shows the characteristics of the carbon fiber spun yarn fabric obtained from the PVA fiber-containing carbon fiber precursor spun yarn fabric of Example 1-4. The properties of the carbon fiber spun yarn fabric obtained in Example 1-4 were all good.

[Examples 5 to 8]
PAN-based oxidized fiber (OPF) [fiber length 51 mm, fineness 1.4 dtex, crimp number 400 pieces / m, crimp rate 10%] and cellulose fiber [fiber length 51 mm, fineness 1.4 dtex, crimp number 400 pieces / m, A crimp ratio of 10%] was blended at a blending ratio shown in Table 1, and a cellulose fiber-containing carbon fiber precursor spun yarn having a lower twist number of 1000 times / m and an upper twist number of 480 times / m and a meter count of 2/80 Nm. Manufactured.

  Using this cellulose fiber-containing carbon fiber precursor spun yarn, a cellulose fiber-containing carbon fiber precursor spun yarn fabric having a history of 20/20 / cm was produced (Example 5-8). In Example 5-7, carbon fiber precursor spun yarn containing cellulose fiber was used for warp and weft. In Example 8, the cellulose fiber-containing carbon fiber precursor spun yarn was used only for the weft, and the warp yarn was a carbon fiber precursor spun yarn not containing the cellulose fiber.

  The obtained cellulose fiber-containing carbon fiber precursor spun yarn fabric was subjected to a heat treatment at 1600 ° C. for 5 minutes to thermally decompose and reduce the cellulose fibers to obtain a carbon fiber spun yarn fabric.

  Table 1 shows the characteristics of the carbon fiber spun yarn fabric obtained from the cellulose fiber-containing carbon fiber precursor fabric of Examples 5-8. The characteristics of the carbon fiber spun yarn fabrics obtained in Examples 5 to 8 were all good.

[Example 9]
PAN-based oxidized fiber (OPF) [fiber length 51 mm, fineness 1.4 dtex, crimp number 400 pieces / m, crimp rate 10%] and PVA fiber [fiber length 51 mm, fineness 1.4 dtex, crimp number 400 pieces / m, A PVA fiber-containing carbon fiber precursor spun yarn having a crimp rate of 10%] was twisted at an upper twist number of 480 times / m.
As the PAN-based oxidized fiber of the PVA fiber-containing carbon fiber precursor spun yarn, one having a metric number of 1/80 Nm was used for both warp and weft. As the PVA fiber, one having a twist of 1000 times / m and a metric count of 1/120 Nm was used.
Using the obtained PVA fiber-containing carbon fiber precursor spun yarn, a PVA fiber-containing carbon fiber precursor spun yarn fabric with a history = 20/20 / cm was produced (Example 9).

  The obtained PVA fiber-containing carbon fiber precursor spun yarn fabric was refined with water at 95 ° C. for 20 minutes, and only the PVA fibers were eluted to obtain a carbon fiber precursor spun yarn fabric.

  The obtained carbon fiber precursor spun yarn fabric was carbonized by heat treatment at 1600 ° C. for 5 minutes to obtain a carbon fiber spun yarn fabric.

  Table 2 shows the characteristics of the carbon fiber spun yarn fabric obtained in Example 9. The properties of the carbon fiber spun yarn fabric obtained in Example 9 were good.

[Example 10]
For the warp, a carbon fiber precursor spun yarn having a metric count of 2/80 Nm was used. For the weft, a PVA fiber-containing carbon fiber precursor spun yarn was used. The metric number of the PAN-based oxidized fiber of the weft is 1/80 Nm, and the metric number of the PVA-containing fiber is 1/120 Nm. A PVA fiber-containing carbon fiber precursor spun yarn fabric composed of the above warp and weft was produced (Example 10).

  The obtained PVA fiber-containing carbon fiber precursor spun yarn fabric was refined with water at 95 ° C. for 20 minutes, and only the PVA fibers were eluted to obtain a carbon fiber precursor spun yarn fabric.

  The obtained carbon fiber precursor spun yarn fabric was carbonized by heat treatment at 1600 ° C. for 5 minutes to obtain a carbon fiber spun yarn fabric.

  Table 2 shows the characteristics of the carbon fiber spun yarn fabric obtained in Example 10. The properties of the carbon fiber spun yarn fabric obtained in Example 10 were good.

[Example 11]
PAN-based oxidized fiber (OPF) [fiber length 51 mm, fineness 1.4 dtex, crimp number 400 pieces / m, crimp rate 10%] and cellulose fiber [fiber length 51 mm, fineness 1.4 dtex, crimp number 400 pieces / m, A cellulose fiber-containing carbon fiber precursor spun yarn having a crimp rate of 10%] was twisted at an upper twist number of 480 times / m.
The PAN-based oxidized fiber of the cellulose fiber-containing carbon fiber precursor spun yarn was 1/80 Nm in metric number for both warp and weft. Cellulose fibers having a primary twist of 1000 times / m and a metric count of 1/120 Nm were used.
Using the obtained cellulose fiber-containing carbon fiber precursor spun yarn, a cellulose fiber-containing carbon fiber precursor spun yarn fabric having a history of 20/20 / cm was produced (Example 11).

  The obtained carbon fiber precursor spun yarn fabric was carbonized by heat treatment at 1600 ° C. for 5 minutes to obtain a carbon fiber spun yarn fabric.

  Table 2 shows the properties of the carbon fiber spun yarn fabric obtained in Example 11. The properties of the carbon fiber spun yarn fabric obtained in Example 11 were good.

[Example 12]
For the warp, a carbon fiber precursor spun yarn having a metric count of 2/80 Nm was used. A cellulose fiber-containing carbon fiber precursor spun yarn was used as the weft. The metric number of the PAN-based oxidized fiber of the weft is 1/80 Nm, and the metric number of the cellulose fiber is 1/120 Nm. A cellulose fiber-containing carbon fiber precursor spun yarn woven fabric composed of the above warp and weft was produced (Example 12).

  The obtained carbon fiber precursor spun yarn fabric was carbonized by heat treatment at 1600 ° C. for 5 minutes to obtain a carbon fiber spun yarn fabric.

  Table 2 shows the characteristics of the carbon fiber spun yarn fabric obtained in Example 12. The properties of the carbon fiber spun yarn fabric obtained in Example 12 were good.

[Comparative Example 1-3]
Comparative Example 1-3 is a carbon fiber precursor spun yarn fabric produced using a carbon fiber precursor spun yarn that does not contain evanescent fibers. The carbon fiber precursor spun yarn used in Comparative Example 1-3 is PAN-based oxidized fiber (OPF) [fiber length 51 mm, fineness 1.4 dtex, crimp number 400 pieces / m, crimp rate 10%] A material having a twist number of 1000 times / m and an upper twist number of 480 times / m was used as a raw material. The metric counts of these carbon fiber precursor spun yarns were 2/50 Nm in Comparative Example 1, 2/120 Nm in Comparative Example 2, and 2/40 Nm in Comparative Example 3.

In Comparative Example 1, using the obtained carbon fiber precursor spun yarn for warp and weft, a carbon fiber precursor spun woven fabric with warp = 20/20 yarns / cm was produced (Comparative Example 1).
The obtained carbon fiber precursor spun yarn fabric was carbonized by heat treatment at 1600 ° C. for 5 minutes to obtain a carbon fiber spun yarn fabric.
Table 3 shows the characteristics of the carbon fiber spun yarn fabric obtained in Comparative Example 1. The carbon fiber spun yarn fabric obtained in Comparative Example 1 had a thickness of 320 μm and was not suitable for a gas diffusion electrode of a small fuel cell.

  In Comparative Example 2, the carbon fiber precursor spun yarn was broken during weaving, and a carbon fiber precursor woven fabric could not be obtained.

In Comparative Example 3, the obtained carbon fiber precursor spun yarn was used for warp and weft to produce a carbon fiber precursor spun woven fabric of warp = 20/20 / cm (Comparative Example 3).
The obtained carbon fiber precursor spun yarn fabric was hot pressed at 300 ° C. and a load of 200 kg / cm, and then carbonized at 1600 ° C. for 5 minutes to obtain a carbon fiber spun yarn fabric.
Table 3 shows the characteristics of the carbon fiber spun yarn fabric obtained in Comparative Example 3. The carbon fiber spun yarn fabric obtained in Comparative Example 3 had a bending resistance of 15 mNcm, and wrinkles occurred when wound on a paper tube having an outer diameter of 2.54 cm (1 inch). The metric count of the carbon fiber spun yarn is out of the predetermined range of the present invention, and the carbon fiber spun yarn woven fabric has too little space.

[Comparative Example 4]
PAN-based oxidized fiber (OPF) [fiber length 51 mm, fineness 1.4 dtex, crimp number 400 pieces / m, crimp rate 10%] and polyester fiber [fiber length 51 mm, fineness 1.4 dtex, crimp number 400 pieces / m, A crimp rate of 10%] was blended at a blending ratio of 30% by mass to produce a polyester fiber blended carbon fiber precursor spun yarn having a lower twist number of 1000 times / m and an upper twist number of 480 times / m.
The metric count of the polyester fiber blended carbon fiber precursor spun yarn was 2/80 Nm for both warp and weft.
Using the obtained polyester fiber blended carbon fiber precursor spun yarn, a polyester fiber blended carbon fiber precursor spun yarn fabric having a history of 20/20 yarns / cm was produced (Comparative Example 4).

  The obtained polyester fiber blended carbon fiber precursor spun yarn fabric is hot-pressed at 160 ° C. under a load of 200 kg / cm, and then carbonized by heat treatment at 1600 ° C. for 5 minutes to obtain a carbon fiber spun yarn fabric. Got.

  Table 3 shows the characteristics of the carbon fiber spun yarn fabric obtained from the polyester fiber blended carbon fiber precursor spun yarn fabric of Comparative Example 4. The carbon fiber spun yarn fabric obtained in Comparative Example 4 had a bending resistance of 30 mNcm. For this reason, wrinkles were generated when the paper tube having an outer diameter of 2.54 cm (1 inch) was wound.

[Comparative Examples 5 and 6]
In Comparative Examples 5 and 6, PAN-based oxidized fiber (OPF) [fiber length 51 mm, fineness 1.4 dtex, crimp number 400 pcs / m, crimp rate 10%] and PVA fiber [fiber length 51 mm, fineness 1.4 dtex, Spinning number 400 crimps / m, crimping rate 10%] at a blending ratio shown in Table 3 with a lower twist number of 1000 times / m and an upper twist number of 480 times / m, PVA fiber-containing carbon fiber precursor spinning Yarn was produced. In Comparative Examples 5 and 6, as shown in Table 3, the blend ratio of PVA fibers is out of the range of 10 to 50% by mass.
The metric count of the PVA fiber-containing carbon fiber precursor spun yarn was 2/40 Nm in Comparative Example 5 for both warp and weft. In Comparative Example 6, both for the weft and the warp were 2/45 Nm.
Using these PVA fiber-containing carbon fiber precursor spun yarns, weaving was performed at a history of 20/20 yarns / cm to produce carbon fiber precursor spun yarn fabrics (Comparative Examples 5 and 6).

  The obtained PVA fiber blended carbon fiber precursor spun yarn fabric was refined with water at 95 ° C. for 20 minutes to elute the PVA fibers. In Comparative Example 5, since the blend ratio of PVA fibers is as high as 80% by mass, when the PVA fibers are eluted, the strength of the carbon fiber precursor spun yarn fabric is reduced, and the PVA fiber-containing carbon fiber precursor spun yarn fabric is refined. Breakage occurred in the process.

In Comparative Example 6, the PVA fiber-containing carbon fiber precursor spun yarn fabric was refined to elute the PVA fibers, and then carbonized by heat treatment at 1600 ° C. for 5 minutes to obtain a carbon fiber spun yarn fabric. .
Table 3 shows the characteristics of the carbon fiber spun yarn fabric obtained from the PVA fiber-containing carbon fiber precursor spun yarn fabric of Comparative Example 6. Since the carbon fiber spun yarn fabric obtained in Comparative Example 6 has a low PVA fiber blending ratio of 5% by mass, the thickness of the carbon fiber spun yarn is much less after refining than before the PVA fiber is eluted. It didn't get thinner. Therefore, the thickness of the obtained carbon fiber spun yarn fabric exceeded 300 μm.

[Comparative Examples 7 and 8]
In Comparative Examples 7 and 8, PAN-based oxidized fiber (OPF) [fiber length 51 mm, fineness 1.4 dtex, crimp number 400 pieces / m, crimp rate 10%] and cellulose fiber [fiber length 51 mm, fineness 1.4 dtex, The number of crimps is 400 pcs / m, the crimp rate is 10%, and the blend ratio is as shown in Table 3. The number of lower twists is 1,000 times / m, the number of upper twists is 480 times / m, and the meter count is 2/80 Nm. Containing carbon fiber precursor spun yarn was produced. In Comparative Examples 7 and 8, as shown in Table 3, the blend ratio of cellulose fibers is out of the range of 10 to 50% by mass.
The metric count of the cellulose fiber-containing carbon fiber precursor spun yarn was 2/40 Nm in Comparative Example 7 for both warp and weft. In Comparative Example 8, both for the weft and the warp were 2/45 Nm.
Using this cellulose fiber-containing carbon fiber precursor spun yarn for warp and weft, weaving at warp = 20/20 yarns / cm to produce a cellulose fiber blended carbon fiber precursor spun yarn fabric (Comparative Examples 7 and 8) .
The obtained cellulose fiber mixed carbon fiber precursor spun yarn fabric was carbonized by heat treatment at 1600 ° C. for 5 minutes.

  In Comparative Example 7, the blend ratio of cellulose fibers is as high as 80% by mass. Therefore, when the cellulose fiber is reduced from the cellulose fiber blended carbon fiber precursor spun yarn in the carbonization step by heat treatment, the strength of the carbon fiber precursor spun yarn is reduced, the carbon fiber precursor spun yarn is broken, and the carbon fiber A spun yarn fabric could not be produced.

In Comparative Example 8, a carbon fiber spun yarn fabric was obtained by carbonizing a blended cellulose fiber blended carbon fiber precursor spun yarn fabric at 1600 ° C. for 5 minutes.
Table 3 shows the characteristics of the carbon fiber spun yarn fabric obtained from the cellulose fiber-containing carbon fiber precursor spun yarn fabric of Comparative Example 8. Since the carbon fiber spun yarn fabric obtained in Comparative Example 8 had a low blending ratio of cellulose fibers of 5%, the thickness of the obtained carbon fiber spun yarn fabric exceeded 300 μm.
About Comparative Examples 1-8 in Table 3, the location shown by x has deviated from the configuration of the present invention.

Claims (10)

A carbon fiber precursor spun yarn fabric obtained by weaving a carbon fiber precursor spun yarn, at least a carbon fiber precursor spun yarn serving as a weft is blended with a carbon fiber precursor fiber and the carbon fiber precursor fiber. Or a vanishable fiber-containing carbon fiber precursor spun yarn made from a vanishing fiber to be twisted together,
The vanishable fiber is a carbon fiber precursor spun yarn fabric comprising a component that can disappear from the carbon fiber precursor spun yarn after weaving the carbon fiber precursor spun yarn fabric. The carbon fiber precursor spun yarn fabric according to claim 1 , wherein the carbon fiber precursor fiber is a carbon fiber precursor staple. The carbon fiber precursor spun yarn fabric according to claim 1 , wherein the vanishing fiber is a water-soluble fiber that elutes in water of 100 ° C. or less. The carbon fiber precursor fiber is a carbon fiber precursor staple, and the water-soluble fiber blended with the carbon fiber precursor staple is a water-soluble fiber staple,
The carbon fiber precursor spun yarn fabric according to claim 1 or 3 , wherein a blending ratio of the water-soluble fiber staple in the vanishing fiber-containing carbon fiber precursor spun yarn is 10 to 50% by mass. The carbon fiber precursor fiber is a carbon fiber precursor spun yarn or carbon fiber precursor strand,
The carbon fiber according to claim 1 or 3 , wherein the water-soluble fiber twisted together with the carbon fiber precursor spun yarn or the carbon fiber precursor strand is a water-soluble fiber spun yarn or a water-soluble fiber strand. Precursor spun yarn fabric. The fugitive fibers, under an inert gas atmosphere, in firing conditions from 1,300 to 2,300 ° C., a non-melting, and the residue after firing is not more than 10 wt%, a Teizansumi fibers, according to claim 1 or The carbon fiber precursor spun yarn fabric according to claim 2 . The carbon fiber precursor fiber is a carbon fiber precursor staple,
The low residual carbon fiber blended with the carbon fiber precursor staple is a low residual carbon fiber staple,
The carbon fiber precursor spun yarn fabric according to claim 1 or 6 , wherein a blend ratio of the low residual carbon fiber staple in the vanishing fiber-containing carbon fiber precursor spun yarn is 10 to 50% by mass. The carbon fiber precursor fiber is a carbon fiber precursor spun yarn or carbon fiber precursor strand,
The low residual carbon fibers wherein the carbon fiber precursor spun yarn or the carbon fiber precursor strands and Goyo is Teizansumi fiber spun yarn or Teizansumi fiber strands, either claim 1, 2, 6 carbon fiber precursor spun yarn fabric according to item 1 or. The used carbon fiber precursor spun yarn containing a water-soluble fibers as at least the weft, woven carbon fiber precursor spun yarn fabric according to any one of claims 1 to 5,
Refining the carbon fiber precursor spun yarn fabric with water at 100 ° C. or less to eliminate only the water-soluble fibers from the carbon fiber precursor spun yarn fabric,
The carbon fiber precursor spun yarn fabric from which the water-soluble fibers have disappeared is carbonized by firing at 1300 to 2300 ° C. for 0.5 to 10 minutes in an inert gas atmosphere,
A carbon fiber spun woven fabric having a thickness of 50 to 300 μm, a basis weight of 10 to 80 g / m ² , a bending resistance of 10 mNcm or less, an electric resistance value of 200 mΩ / cm ² or less, and a porosity of 2 to 20%, The metric count of carbon fiber spun yarn constituting the woven fabric is a carbon fiber spun yarn fabric selected from the group consisting of 1/60 to 1/200 Nm single yarn and 2/120 to 2/400 Nm twin yarn. A method for producing a carbon fiber spun yarn fabric. The carbon fiber precursor spun yarn fabric according to any one of claims 1, 2, 6, 7 , and 8 is woven using at least the carbon fiber precursor spun yarn containing the low residual carbon fiber as a weft. ,
The carbon fiber precursor spun yarn fabric is fired at 1300 to 2300 ° C. for 0.5 to 10 minutes in an inert gas atmosphere to reduce the low residual carbon fiber from the carbon fiber precursor spun yarn fabric, Carbonizing the carbon fiber precursor spun yarn fabric,
A carbon fiber spun woven fabric having a thickness of 50 to 300 μm, a basis weight of 10 to 80 g / m ² , a bending resistance of 10 mNcm or less, an electric resistance value of 200 mΩ / cm ² or less, and a porosity of 2 to 20%, The metric count of carbon fiber spun yarn constituting the woven fabric is a carbon fiber spun yarn fabric selected from the group consisting of 1/60 to 1/200 Nm single yarn and 2/120 to 2/400 Nm twin yarn. A method for producing a carbon fiber spun yarn fabric.