JP6095159B2 - Method for producing conductive cellulose fiber material - Google Patents

Description

  The present invention relates to a method for producing a conductive cellulose fiber material that imparts conductivity to a cellulose fiber material.

  Conventionally, as a method for imparting conductivity to a fiber, a method for producing a conductive fiber by kneading a conductive filler such as acetylene carbon black into the fiber has been proposed. Such a method for producing a conductive fiber is widely used in many industrial fields because it is relatively inexpensive and suitable for mass production. For example, such conductive fibers have been widely put into practical use as charging and neutralizing brushes used in electrostatic copying machines.

As the raw yarn used for the brush of the conventional brush-type charging device, conductive regenerated cellulose fibers in which conductive carbon black is uniformly dispersed in regenerated cellulose (for example, see Patent Documents 1 and 2) are used. Such a conductive regenerated cellulose fiber has a basic problem that it has a limit in electric conduction performance due to a chain of conductive carbon particles and does not reach a volume specific resistance of 10 ² Ω · cm or less, which is an antistatic performance level. . Furthermore, it was extremely difficult to prevent secondary agglomeration of the added carbon fine particles no matter how small the particle size, so that the fiber spinning was poor, and the agglomerated carbon was not suitable for the performance change due to the environment of regenerated cellulose. Have the disadvantage of being sensitively affected. In the case of spinning kneading, it is necessary to uniformly disperse carbon black at a high concentration. However, uniform dispersion due to aggregation and sedimentation of filler in a conductive filler spinning solution such as carbon of several μm to several tens of μm Practically difficult. As a result, the fibers are brittle and have poor mechanical properties as a brush. In addition, when the matrix polymer is a synthetic polymer thermoplastic resin such as nylon, polyester, or olefin, the internal temperature becomes high due to heating during fixing in a copying machine, etc. It is required that the synthetic fiber does not deform even when subjected to heat for a long time. For this reason, cellulose having heat resistance has been an important polymer material.

In recent years, with the rapid spread of mobile phones and electronic devices, problems such as the influence of electromagnetic waves leaking from these devices on the human body and malfunctions of other electronic devices have been addressed. A conductive fabric is used as a shielding material for shielding such electromagnetic waves. When used as a shielding material, higher conductivity performance is required, and a kneaded fiber or the like of a conductive filler whose volume resistivity does not become 10 ² Ω · cm or less cannot exhibit electromagnetic wave shielding performance.

  It is widely known that a metal coating is formed on the surface of a lightweight and flexible synthetic fiber to impart conductivity, and the metal coating is formed by vacuum deposition, sputtering, electroless plating, or the like. It is possible. However, the metal film produced by such a method has problems such as wear resistance, weather resistance, and deterioration of physical properties due to chemical changes associated with long-term use, and further improvement for such problems is demanded.

As a method for imparting conductivity to acrylic fibers, after a copper compound such as cupric chloride is adsorbed on the fiber surface, this is reduced with sulfide to form a copper sulfide thin film layer showing conductivity on the fiber surface. A technique for forming the layer is known (see, for example, Patent Documents 3 and 4). In such a conductivity imparting method, copper sulfide is bonded to the fiber by about 5 to 15% by mass via a copper ion capturing group such as a cyano group or a mercapton group existing on the surface of the fiber. When a thin film layer having a thickness of 10 is formed, high conductive performance of 10 ⁻¹ Ω · cm or less is exhibited. However, the obtained conductive fiber is only a copper sulfide layer with a very thin surface of about 100 nm. Like the plating layer and vapor deposition film, the abrasion resistance and weather resistance, and the durability against wear and chemical changes associated with long-term use. There was a problem. Furthermore, cyano groups and mercapton groups present on the surface of the fiber are excellent in monovalent copper ion scavenging ability, so it is necessary to reduce divalent copper salts to monovalent copper ions during the treatment process. There is also a problem that the cost increases accordingly. As described above, the conventional method for imparting electrical conductivity to acrylic fibers has a problem that the cost burden is large and there is a great limitation in achieving practical use.

The above-mentioned carbon filler-kneaded fibers are technically only moderately conductive (10 ² Ω · cm to ^{10 10} Ω · cm), and chemical plating and metal-plated fibers have high conductivity (10 Only those having ⁻² to 10 ⁻⁶ Ω · cm) can be obtained. Therefore, it is difficult to obtain a fiber material of about 10 ² Ω · cm to 10 ⁻² Ω · cm, which is required for products such as planar heating elements, electromagnetic shielding materials that do not generate streamers (spark discharge), and sensors. there were.

In recent years, a method of coating a yarn or fabric by blending a CNT (carbon nanotube) dispersion with a binder or the like has been proposed. Since CNT has a very strong cohesive force and it is more difficult to knead and disperse it in a polymer than carbon fine particles, a method of blending into a dispersion is employed (for example, see Patent Document 5). In terms of performance, the volume resistivity is 1.0 × 10 ⁻² Ω · cm to 1.0 × 10 ² Ω · cm. Fiber materials in this volume resistivity range include metal wire substitute heating elements, conductive fiber materials for anti-static that do not generate streamers, electromagnetic wave shielding materials made of non-ferrous metal conductive fibers, or conductive materials for electrical signal circuits such as smart textiles. Suitable for applications such as fiber materials. However, in the case of using CNTs, the safety at the time of using nanomaterials such as CNTs has not been sufficiently established and has not yet been put into practical use. In that respect, the conductivity imparting method using copper sulfide described above has a smaller risk to safety than the conductivity imparting method using CNT.

Recently, a method for producing PVA (polyvinyl alcohol) -based fibers having excellent conductivity by finely dispersing copper sulfide nanoparticles in the fibers has been proposed (see, for example, Patent Documents 6 to 8). According to this method, it is possible to produce a conductive fiber having a volume resistivity of 1.0 × 10 ^{−3 to} 1.0 × 10 ⁸ Ω · cm, but it is formed inside the PVA fiber. The resulting copper sulfide particles have a shape with a recognizable particle diameter, and since only fine particles with a low degree of polymerization or crystallinity of PVA can be precipitated, only fine particles having almost similar shapes can be formed. It was. Therefore, the PVA fiber having a low crystallinity has a problem of being dissolved or contracted in hot water.

JP 2000-160427 A JP-A-9-49116 JP 57-21570 A JP 59-108043 A JP 2007-39623 A JP 2005-264419 A Japanese Patent Laid-Open No. 2007-131977 Japanese Patent Application Laid-Open No. 2007-119950

  The present inventors use a cellulose polymer material having a hydrogen bond strength between molecular chains stronger than that of PVA, using a cellulose polymer material having a fiber crystal structure as a raw material, and depositing copper sulfide fine particles under alkali swelling. Based on the crystal structure of the cellulosic polymer material, it was found that these fine particles are formed as amorphous particles inside and rod-shaped fine particles are formed on the outer peripheral portion of the fiber surface.

  Then, in view of the subject of the prior art mentioned above, this invention aims at providing the manufacturing method which can provide electroconductivity to a cellulose fiber material, and can manufacture the electroconductive cellulose fiber material which has durability. And

The method for producing a conductive cellulose fiber material according to the present invention includes a swelling step of swelling a cellulose fiber material with an aqueous solution containing an alkali metal hydroxide at a swelling rate of 20% by mass to 300% by mass, and a compound containing copper ions. Impregnation step of impregnating the outer periphery and inside of the cellulosic fiber material with copper ions with an aqueous solution in which a concentration of 5 g / liter to 70 g / liter is dissolved, and a compound containing sulfide ions at a concentration of 5 g / liter to 120 g / liter Copper ions impregnated into the cellulosic fiber material are sulfidized and reduced with the dissolved aqueous solution, and fine particles comprising rod-shaped copper sulfide having a length of 200 nm or less on the outer peripheral portion of the cellulosic fiber material and non-particles having an average particle diameter of 50 nm or less inside. And a sulfidation-reduction step for producing fine particles made of regular copper sulfide. Further, the swelling step is performed in parallel with the impregnation step. Further, in the impregnation step, a carboxylic acid having a concentration of 0 g / liter to 70 g / liter is contained in the aqueous solution.

  According to the present invention, a conductive cellulose fiber material having heat resistance and hot water resistance imparted with conductivity can be obtained, and the volume specific resistance value of the fiber material can be easily adjusted.

It is the photograph which image | photographed the fiber surface of the electroconductive cellulose fiber material obtained in Example 1 with SEM. It is the photograph which image | photographed the fiber cross section of the electroconductive cellulose fiber material obtained in Example 1 with TEM. It is the photograph which image | photographed the fiber surface of the electroconductive cellulose fiber material obtained in Example 4 with SEM. It is the photograph which image | photographed the fiber cross section of the electroconductive cellulose fiber material obtained in Example 4 with TEM. When the combination of the concentrations of copper acetate and sodium sulfide obtained in Examples 1 to 10 was changed, the volume resistivity value and the concentration of copper (II) acetate monohydrate for the conductive yarn were changed. It is a graph which shows the volume specific resistance value regarding the electroconductive thread | yarn in the case. In Example 12, it is a graph which shows the volume specific resistance value regarding an electroconductive thread | yarn when changing the combination of the frequency | count of an impregnation process and a sulfide reduction process, and the density | concentration of sodium sulfide. It is a graph which shows the relationship between the citric acid addition density | concentration obtained in Example 13 to Example 17, and the volume resistivity of an electroconductive fabric. In Example 18, it is a graph which shows the relationship between electricity supply time (second) and the average temperature (degreeC) of a fabric.

  Hereinafter, the present invention will be specifically described. The cellulose fiber material used in the present invention is not particularly limited, but considering the mechanical properties and dimensional stability of the obtained fiber material, regenerated cellulose fiber material, cellulose diacetate fiber material, cellulose triacetate fiber Material is preferred. In the case of a regenerated cellulose fiber material, it can be obtained by a production method such as a viscose rayon method, a copper ammonia man-silk method, or a lyocell method using an NMMO (N-methylmorpholine oxide) organic solvent.

  Further, the form of the cellulosic fiber material is not particularly limited as long as it can be processed as described later, but the form of fibers such as staple fiber and shortcut fiber, the form of yarn such as long fiber yarn and spun yarn, Examples of the shape of a long object such as a string or rope, and the form of a fabric such as paper, nonwoven fabric, woven fabric, or knitted fabric can be given.

  The cross-sectional shape of the fiber is not particularly limited, and may be circular, hollow, or an atypical cross section such as a star shape. The fineness of the fiber is not particularly limited, and for example, a fiber having a fineness of 0.1 to 10000 dtex, preferably 1 to 1000 dtex can be used. What is necessary is just to adjust the fineness of a fiber suitably with a nozzle diameter or a draw ratio.

  In general, it is known that a cellulosic polymer is strongly coordinated with a metal ion such as copper via its hydroxyl group (see, for example, Polymer, Vol 37, No. 14, 3097, 1996). Since the complex block formed of cellulose molecular chains and copper ions in the fiber has a size of several angstroms, it can be a copper sulfide nanoparticle constituent unit described later. In the present invention, first, copper ions are permeated into the inside of the cellulosic fiber material and coordinated with the hydroxyl group of the cellulosic polymer to form a coordinate bond between the cellulosic polymer and copper. In order to form such a coordination bond, a cellulosic fiber material that is in a predetermined swollen state with a bath solvent in a yarn or fabric dyeing process is passed through a bath in which a compound containing copper ions is dissolved. The copper ions can be uniformly permeated from the outer periphery to the inside of the fiber material, and can be coordinated.

  Next, copper sulfide nanoparticles can be formed by subjecting copper ions coordinated with the hydroxyl groups of the cellulosic polymer in the outer periphery and inside of the cellulosic fiber material to a sulfide reduction treatment. That is, following the copper ion impregnation treatment described above, by passing through a bath in which a compound containing sulfide ions having sulfide reduction ability is dissolved, by removing the coordination between the cellulose polymer and the copper ions, Copper sulfide fine particles can be formed even inside the fiber. Such a sulfidation reduction treatment does not require any special expensive process, and can be carried out in a normal dyeing process.

  The compound containing a copper ion used in the present invention is not particularly limited as long as it is soluble, but copper acetate, copper nitrate, copper formate, copper citrate, cuprous chloride, cupric chloride, odor Cuprous iodide, cupric bromide, cuprous iodide, cupric iodide, and the like are used. Such copper ions may be monovalent or divalent and are not particularly limited. When a compound containing monovalent copper ions is used, hydrochloric acid, potassium iodide, ammonia, or the like may be used in combination for the purpose of improving the solubility. Among these, those that are easy to coordinate with a cellulosic polymer in a solution state are more desirable, and from this viewpoint, the copper ion-containing compound is preferably copper acetate or copper nitrate.

  In the present invention, it is preferable to use a carboxylic acid in order to inhibit copper ions from being precipitated as copper hydroxide in the presence of an alkali. Examples of the carboxylic acid include, but are not limited to, formic acid, acetic acid, malonic acid, succinic acid, glutaric acid, citric acid, and tartaric acid. Among these, those that form a complex with copper ions and inhibit the copper ions from precipitating as copper hydroxide in the presence of alkali are more desirable, and citric acid is preferred from that viewpoint.

  A compound capable of releasing sulfide ions is used as the sulfiding agent for sulfidation reduction of copper ions coordinated and bonded at the outer periphery and inside of the cellulosic fiber material. Examples of such compounds include sodium sulfide, sodium dithionate, sodium thiosulfate, sodium hydrogen sulfite, sodium pyrosulfate, hydrogen sulfide, thiourea, thioacetamide, and the like. Among these, sodium sulfide is preferable from the viewpoints of cost, availability, and low corrosivity.

  Unlike the conventional conductive fibers, the conductive cellulose fiber material obtained in the present invention is a method in which fine particles made of copper sulfide are dispersed and precipitated on the outer periphery and inside of the fiber material to significantly reduce the distance between the particles. Thus, it is a fiber material that can increase the amount of current when the fiber material is energized and has excellent conductivity.

  In the present invention, in order to obtain a conductive cellulose fiber material, the dried fiber material or the fiber material after stretching is subjected to a swelling treatment with an aqueous solution of a compound containing an alkali metal hydroxide. Examples of the alkali metal hydroxide include sodium hydroxide, potassium hydroxide, cesium hydroxide, lithium hydroxide, rubidium hydroxide and the like, and it is preferable to use sodium hydroxide which is the cheapest from the viewpoint of price. Then, the outer peripheral portion and the inside of the fiber material are impregnated with a compound containing copper ions by passing through a bath in which a compound containing copper ions and an alkali metal hydroxide are dissolved. The cellulose fiber material may be subjected to a swelling treatment with an alkali metal hydroxide in advance and then impregnated with a compound containing copper ions.

  It is necessary to swell the fiber material with a bath solvent in order to uniformly impregnate the periphery and inside of the cellulosic fiber material with a compound containing copper ions and coordinate the copper ions to the hydroxyl groups of the cellulosic polymer. It is. When sodium hydroxide is used as the alkali metal hydroxide, it is preferable to add 3 to 10% by weight of sodium hydroxide in the bath solvent. When the amount of sodium hydroxide added is less than 3% by weight, there is a problem that the amount of copper sulfide deposited is small and the desired conductive performance cannot be obtained. There is a problem that the degree of strength is reduced and the mechanical strength of the conductive fiber is lowered. And the volume specific resistance of the electroconductive cellulose fiber material obtained can be reduced by increasing the addition amount of sodium hydroxide.

  And when swelling a cellulose fiber material with the bath solvent containing an alkali metal hydroxide, it is preferable that the swelling rate of a fiber material is 20 mass% or more. When the swelling ratio is less than 20% by mass, copper ions cannot form a sufficient coordination bond with the hydroxyl group of the cellulosic polymer, and it becomes difficult to produce fine particles made of copper sulfide up to the inside of the fiber material. On the other hand, when the swelling ratio becomes too large, elution of the cellulosic polymer into the bath occurs, which is not preferable in terms of process passability. From the above, the swelling ratio in the bath in which the compound containing copper ions is dissolved is preferably 20% by mass to 300% by mass, and more preferably 50% by mass to 250% by mass. In order to adjust the swelling rate, the fiber material can be first immersed in a bath containing an alkali metal hydroxide, and then immersed in a bath in which a compound containing copper ions is dissolved.

  As described above, the volume specific resistance value of the cellulosic fiber material can be adjusted by adjusting the introduction amount of copper sulfide, the degree of orientation of the fiber material, and the like with respect to the cellulosic fiber material. The amount of the compound containing copper ions in the bath may be appropriately set according to the required conductivity performance, but is preferably in the range of 1 g / liter to 100 g / liter, more preferably 5 g / liter. ~ 70 g / liter. When the addition amount is less than 1 g / liter, a desired volume resistivity value cannot be obtained. When the addition amount is more than 100 g / liter, there is a problem in process such as adhesion of a compound to a processing roller or the like used for processing. Since it occurs, it is not preferable.

  When the cellulosic fiber material is in the desired swollen state, the fiber material is impregnated with a compound containing copper ions when passing through the cellulosic fiber material in a bath in which copper ions are dissolved. There is no particular restriction on the residence time of the fiber material, but in order to uniformly impregnate the copper ions even inside the fiber material and to sufficiently generate the coordination bonds of the cellulosic polymer and copper ions, The residence time of the fiber material at 3 is set to 3 seconds or more, preferably 30 seconds or more.

  In order to sulfidize and reduce copper ions coordinated at the outer periphery and inside of the cellulosic fiber material, it is necessary to pass the fiber material through a bath in which a compound containing sulfide ions is dissolved. In this case, the amount of the compound containing sulfide ions added to the bath may be appropriately set depending on the amount of copper ions introduced, but is preferably in the range of 1 g / liter to 200 g / liter. When the addition amount is less than 1 g / liter, the reduction treatment may not proceed to the copper ions inside the fiber material, which is not preferable. On the other hand, when it is larger than 200 g / liter, the amount is sufficient to reduce the copper ions contained in the cellulosic fiber material, but it takes time to recover the compound and the odor during the work becomes strong. The above point is not preferable because of inconvenience. The reaction of sulfiding copper ions impregnated in cellulosic fiber material occurs instantly, especially when a compound having a high sulfidation reduction ability is used, so there is no particular limitation on the residence time of the fiber material in the bath. In order to sufficiently perform the sulfur reduction treatment even inside the fiber material, the residence time of the fiber material in the bath is preferably set to 0.1 seconds or more.

  In order to enhance the conductive performance of the cellulosic fiber material, repeat the steps of impregnating the copper material with the outer periphery and the inside of the fiber material and the step of sulfidation reduction treatment of the impregnated copper ion to contain copper sulfide It is effective to increase the amount. Once the copper ions coordinated to the cellulosic polymer are subjected to sulfidation reduction, fine particles made of copper sulfide are produced. At that time, the hydroxyl groups that have been coordinated to copper ions are recovered, and again the copper ions. There will be a hydroxyl group capable of coordinating. Specifically, by repeating the impregnation step and the sulfidation reduction treatment step described above at least twice, fine particles made of copper sulfide can be effectively generated inside the fiber material, and the conductive performance can be improved. Furthermore, the higher the degree of orientation of the fiber material, that is, the higher the total draw ratio of the fiber material, the better the conductive performance. The reason for this relationship between the degree of orientation and the electrical conductivity is not clear at this stage. However, the higher the degree of orientation of the fiber material, the more fine particles of copper sulfide are generated along the fiber axis direction, and the distance between the fine particles. Is considered to be even smaller. Here, the degree of orientation of the fiber material refers to the degree of orientation after impregnation with copper ions. If stretching is performed after producing fine particles of copper sulfide in the fiber material, the conductive performance tends to decrease, which is not preferable. This is considered to be because the interparticle distance of the fine particles in the fiber material is increased by stretching.

  The conductive cellulosic fiber material produced by the impregnation step and the sulfidation reduction step described above produces irregular fine particles made of copper sulfide having an average particle size of 50 nm or less inside the cellulosic fiber material and the outer periphery of the fiber material. Rod-shaped fine particles made of copper sulfide having a length of 200 nm or less are generated in the part. That is, in the conductive cellulose fiber material, not only fine particles made of copper sulfide are present, but rod-like fine particles made of copper sulfide having a length of 200 nm or less are dispersed and precipitated on the outer peripheral portion of the fiber material. The regular fine particles and the rod-like fine particles on the outer peripheral portion are connected to each other to produce an electric conduction action when a voltage is applied. And electroconductivity can be provided to a cellulose fiber material by making content of the whole microparticles | fine-particles which consist of copper sulfide into 0.5 mass% or more with respect to the quantity of a cellulose fiber material.

As described above, the volume specific resistance value of the obtained conductive cellulose fiber material can be easily adjusted by the amount of introduced copper sulfide, and ranges from 1.0 × 10 ⁻² Ω · cm to 1.0. × 10 ² Ω · cm can be set.

  The conductive cellulose fiber material preferably contains 3% by mass or more, more preferably 5% by mass or more of the fine particles made of copper sulfide with respect to the cellulose fiber material. When the content of fine particles made of copper sulfide is less than 1% by mass with respect to the cellulosic fiber material, desired conductive performance cannot be obtained. On the other hand, if the content of copper sulfide fine particles increases too much, the mechanical properties and wear resistance of the conductive cellulose fiber material will be insufficient. It is preferable that it is 50 mass% or less with respect to material, and it is more preferable that it is 40 mass% or less.

Fine particles made of copper sulfide are finely dispersed and precipitated at a density of 5 particles / (μm) ² or more in the cellulose polymer inside the fiber material with an average particle diameter of 50 nm or less, and on the outer periphery of the fiber material. Rod-shaped fine particles having a length of 200 nm or less are dispersed and precipitated at a density of 5 / (μm) ² or more, and irregular fine particles and rod-shaped fine particles are connected to each other. Thus, the distribution of the fine particles of copper sulfide makes it possible to significantly reduce the distance between the fine particles in the fiber material. For example, it is known that when the particle diameter becomes 1/100 in the same mass% content, the inter-particle distance is reduced to 1 / 10,000. In such a case, it is also known that the interaction between the particles works very strongly, and the polymer molecules sandwiched between them show the same function as the particles (for example, Sumio Nakajo, Nano See the world of composites, p22, Industrial Research Committee, 2000). Therefore, in the produced conductive cellulose fiber material, tunnel current is more likely to flow due to such a nano-size effect, and excellent conductive performance can be imparted even if the amount of fine particles made of copper sulfide is small.

  Since the obtained conductive cellulose fiber material is excellent in conductivity and flexibility, it can be advantageously used as a planar heating element. For example, by using a fabric containing 50% by weight or more, preferably 80% by weight or more, particularly 90% by weight or more of a conductive cellulose fiber material, a cellulose fiber product exhibiting high conductivity can be obtained. In this case, the fiber material that can be used in combination with the conductive cellulose fiber material is not particularly limited, and examples thereof include a cellulose fiber material, a polyester fiber material, and a polyamide fiber material that do not contain fine particles of copper sulfide. .

  In the present invention, conductivity can be imparted to various forms of cellulosic fiber materials such as long fiber yarns, spun yarns, papers, nonwoven fabrics, woven fabrics, knitted fabrics, and the like. The obtained conductive cellulose fiber material is excellent in mechanical properties, heat resistance, flexibility, and conductivity, and can be suitably used for all uses such as industrial materials, clothing, and medical use. For example, it is extremely useful for many applications including planar heating fabrics, charging materials, neutralizing materials, brushes, sensors, electromagnetic wave shielding materials, non-metallic electric wires for electronic circuits, and electronic materials.

  As described above, the present inventors swelled the cellulosic fiber material in an aqueous solution containing an alkali metal hydroxide, and the outer periphery of the cellulosic fiber material in an aqueous solution in which a compound containing copper ions was dissolved. An indefinite shape made of copper sulfide having an average particle diameter of 50 nm or less inside the fiber material by impregnating copper ions inside and subjecting the impregnated copper ions to a sulfide reduction treatment in an aqueous solution in which a compound containing sulfide ions is dissolved. It has been found that rod-shaped fine particles made of copper sulfide having a length of 200 nm or less are formed on the outer periphery of the fine particles and the fiber material, and that it is possible to produce a conductive cellulose fiber material having excellent conductivity at low cost. Such a treatment process does not require specially expensive equipment, and can be carried out in the fiber manufacturing process and the dyeing process of the cellulosic fiber material. Note that the swelling treatment, impregnation treatment, and sulfidation reduction treatment of the cellulosic fiber material can be performed by an application method such as application, spraying, and dipping of the cellulosic fiber material. By using an application method such as coating or spraying, the amount of copper sulfide to be generated can be partially changed if the application amount is partially changed. For this reason, for example, in the case of a planar heating element, it is possible to change the resistance distribution of the heat generating surface and set the desired heat distribution.

  When the cellulose fiber material is immersed in the bath, the cellulose fiber material in an alkali swollen state has a concentration of 5 g / liter to 70 g / liter of a compound containing copper ions and 0 g / liter to 70 g / liter of carboxylic acid. After the copper ions are uniformly impregnated into the fiber material by passing through the bath dissolved in the above, the cellulose fiber material impregnated with the copper ions is added at a concentration of 5 g / liter to 120 g / liter of the compound containing sulfide ions. By passing through a dissolved bath to reduce the copper ions by sulfidation, the above-mentioned amorphous fine particles and rod-shaped fine particles made of copper sulfide are generated.

Further, the obtained conductive cellulose fiber material is an amorphous fine particle comprising a cellulose fiber material and copper sulfide having an average particle diameter of 50 nm or less finely dispersed and precipitated in a cellulose polymer inside the cellulose fiber material. And rod-like fine particles made of copper sulfide having a length of 200 nm or less on the outer periphery of the cellulosic fiber material, and the amorphous particles and the rod-like particles are connected to each other to produce an electric conduction action when a voltage is applied. 0.5 mass% or more is preferable with respect to cellulosic fiber material, and, as for content of the microparticles | fine-particles whole which consist of copper sulfide, it is more preferable that it is 0.5 mass%-50 mass%. Volume resistivity of the conductive cellulosic fiber material is preferably ^{1.0 × 10 -2 Ω · cm~1.0 ×} 10 2 Ω · cm.

  Although it is conceivable to add fine particles of copper sulfide to the stock solution in advance, it is not possible to disperse the fine particles inside the fiber material, and in order to express desired physical properties, a large amount of fine particles must be added. Is required. In this case, poor dispersion of fine particles in the stock solution, aggregation, sedimentation, and the like occur, and it is difficult to obtain a fiber material having good conductive characteristics. In addition, it is conceivable to produce fiber materials using cellulose-based polymers with copper ions coordinated in advance, but the process properties deteriorate, such as an increase in solution viscosity due to copper coordination and deterioration in solidification. In addition to this, the mechanical properties of the resulting fiber must be low.

  EXAMPLES Hereinafter, although this invention is demonstrated further in detail based on an Example, this invention is not limited at all by this Example. In the following Examples, the shape and number of fine particles made of copper sulfide, the volume specific resistance value and strength of the cellulosic fiber material are measured by the following methods.

[Observation of fine particles generated inside fiber material]
For conductive cellulose fiber material, create a slice of fiber material using ultra-thin slice method and FIB (focused ion beam) method, and use TEM (Transmission Electron Microscope) to show fine particles that appear on the cross section of the slice. Observed. In the ultrathin section method, wrinkles (artifacts) are likely to occur during section preparation. In the FIB method, there is a problem that the network structure is observed due to thermal damage during thin film processing. The density of the fine particles appearing on the shape and the cross section of the fiber material was measured. In the FIB method, the sample surface is processed by irradiating the sample surface with a finely focused ion beam and etching the sample surface. When processing a thin film sample, it is processed from the surface of the thin film sample with an ion beam, and finally processed to a thickness (100 nm or less) through which an electron beam passes to obtain a sample for observation. The TEM observation conditions for the cross section of the fiber material were set as follows.
<FIB method>
Sample preparation FIB method: Microsampling system (Hitachi FB-2000A)
Observation device Transmission electron microscope (H-7100FA manufactured by Hitachi)
Observation conditions Acceleration voltage 100kV
<Ultrathin section method>
Sample preparation Ultra-thin section observation device Transmission electron microscope (H-7100FA manufactured by Hitachi)
Observation conditions Acceleration voltage 100kV

[Observation of the surface of the fiber material]
Using SEM (scanning electron microscope; 3D real view microscope VE9800 manufactured by KEYENCE), the surface of the conductive cellulose fiber material was observed. Prior to the observation, the surface of the fiber material was coated with gold using an ion coater.

[Measurement of electrical conductivity (volume resistivity) of fiber material Ω · cm]
5 to 10 fibers made of a conductive cellulose fiber material were randomly selected and arranged in parallel on a slide glass, and silver paste was applied and fixed to both ends of the arranged fibers. The distance between the electrodes was set to 5 mm, and a voltage of 1 to 5 V was applied to the measurement fiber using a DC power supply (TRIO PR-602A DC POWER SUPPLY). Then, the current value at the set voltage was measured with a digital multimeter (manufactured by Sanwa Electric Meter Co., Ltd.). Current measurement was performed five times at a set voltage. And the volume resistivity value of each fiber was calculated | required by the volume resistivity value ((rho)) (ohm * cm) = Rx (S / L). Here, R is the resistance value (Ω) of the test piece, S is the cross-sectional area (cm ² ), and L is the length (5 mm). Here, the cross-sectional area of the fiber was calculated by observing the fiber under a microscope.

[Measurement of fabric conductivity (volume resistivity) Ω · cm]
The surface of the fabric made of conductive cellulose fiber material is washed with a waste cloth soaked with ethanol, and the volume resistivity of the fabric is measured with a resistivity meter (resistivity meter MCP-T370 manufactured by Mitsubishi Chemical Analytech Co., Ltd.). The value was measured. The measurement method was performed according to the four-probe method, and the resistivity correction coefficient was set to 4.532.

[Measurement of tensile strength of fiber materials]
Ten fibers made of a conductive cellulosic fiber material were randomly selected, and the selected fibers were fixed to the support with an epoxy resin. Using a compression tester (KATO TECH CO., LTD high precision compression tester), measurement conditions (chuck distance 20 mm, tensile elongation strain detection 2 mm / 10 V, tensile load detection 100 g / 10 V) were set, and the fiber The strength elongation was measured.

[Measurement of tensile strength of fabric]
A cloth made of a conductive cellulose fiber material was cut into a rectangular shape (10 mm × 50 mm) and used for measurement. For the measurement, a tensile tester (Tensilon type tensile tester UTM-III-500 manufactured by Toyo Baldwin Co., Ltd.) was used, and the measurement conditions (distance between chucks 30 mm, tensile speed 10 mm / min) were set, and the high elongation of the fabric. Was measured.

[Evaluation of heat generation by energizing fabric]
A cloth made of a conductive cellulose fiber material is cut into a rectangular shape (30 mm × 50 mm), and a conductive paste (conductive paste D-500 manufactured by Fujikura Kasei Co., Ltd.) is formed on opposite sides so that the distance between the electrodes is 40 mm. ) And dried at room temperature for 24 hours to form an electrode. A voltage of 15 V was applied to the formed electrode using a DC power supply (DC power supply PR-602A manufactured by Trio Corporation). In order to evaluate the calorific value of the fabric after voltage application, the change over time in the temperature distribution was measured using a thermography (Apiste Thermography FSV-7000E). The measurement conditions were an emissivity of 1, and the temperature was not corrected because the measurement temperature was low.

[Example 1]
(1) Production of conductive yarn made of conductive cellulose fiber material Concentration of 5 g of copper (II) acetate monohydrate (made by Nacalai Tesque) on yarn made of cupra fiber (made by Asahi Kasei Corporation) / Liter and sodium hydroxide (manufactured by Nacalai Tesque Co., Ltd.) were each dissolved at a concentration of 9% by weight and introduced into a 25 ° C. water bath so that the residence time was 120 seconds, and impregnation was performed. The impregnated yarn was subsequently dissolved in a 25 ° C. water bath in which sodium sulfide nonahydrate (manufactured by Nacalai Tesque) was dissolved at a concentration of 40 g / liter and sodium hydroxide (manufactured by Nacalai Tesque) was dissolved at a concentration of 9% by weight. A sulfidation reduction treatment was performed by introducing the yarn so that the residence time was 120 seconds. These impregnation treatment and sulfidation reduction treatment were repeated four times, and then washed sufficiently with water and dried with hot air at 110 ° C. to obtain a conductive yarn made of a conductive cellulose fiber material.

(2) Evaluation of conductive yarn made of conductive cellulose fiber material The initial elastic modulus, elongation at break and breaking strength of the obtained conductive yarn were 178.5 MPa, 2.7% and 94.8 MPa, respectively. It was. The volume specific resistance value of the conductive yarn was 2.8 × 10 ⁻¹ Ω · cm. The appearance of the fibers of the conductive yarn was good and there were no yarn spots. FIG. 1 is a photograph of the fiber surface taken with an SEM. As shown in the photograph in FIG. 1, the deposited fine particles of copper sulfide are exposed, but it can be seen that the surface is smooth. About the weight of the copper sulfide contained in this electroconductive thread | yarn, DTA-TG (differential heat / thermogravimetric) analysis was performed using the differential thermogravimetric analyzer (Shimadzu TG / DTA simultaneous measuring apparatus DTG-60). As a result of DTA-TG analysis up to about 600 ° C., the residual weight was 8% by weight.

FIG. 2 is a photograph of a cross-section of a conductive yarn fiber taken with a TEM. As shown in FIG. 2, it is observed that as fine particles made of copper sulfide, there are amorphous fine particles having an average particle diameter of 50 nm or less inside the fiber and rod-shaped fine particles having a length of the fiber outer peripheral portion of 200 nm or less, which are connected to each other. It was done. The density of amorphous fine particles having an average particle diameter of 50 nm or less was 118 particles / (μm) ² , and the density of rod-shaped fine particles was 54 particles / (μm) ² .

[Example 2]
(1) Production of Conductive Yarn Consisting of Conductive Cellulose-Based Fiber Material A copper (II) acetate monohydrate similar to that in Example 1 was added at a concentration of 10 g / y to a yarn consisting of the same cupra fiber as in Example 1. The impregnation treatment was carried out by introducing the yarn in a 25 ° C. water bath in which the same amount of liter and sodium hydroxide as in Example 1 were dissolved at a concentration of 9% by weight so that the residence time was 120 seconds. The impregnated yarn was subsequently placed in a 25 ° C. water bath in which the same sodium sulfide nonahydrate as in Example 1 was dissolved at a concentration of 40 g / liter and the same sodium hydroxide as in Example 1 was dissolved at a concentration of 9% by weight. The yarn was introduced so as to have a residence time of 120 seconds and subjected to a sulfidation reduction treatment. These impregnation treatment and sulfidation reduction treatment were repeated four times, and then washed sufficiently with water and dried with hot air at 110 ° C. to obtain a conductive yarn made of a conductive cellulose fiber material.

(2) Evaluation of conductive yarn made of conductive cellulose fiber material The initial elastic modulus, elongation at break and breaking strength of the obtained conductive yarn were 172.1 MPa, 2.1% and 73.1 MPa, respectively. It was. The volume specific resistance value of the conductive yarn was 7.4 × 10 ⁻² Ω · cm. As a result of performing DTA-TG analysis up to about 600 ° C. in the same manner as in Example 1 with respect to the weight of copper sulfide contained in the conductive yarn, the residual weight was 15% by weight. Moreover, when analyzed based on the photograph of the fiber cross section of the conductive yarn photographed by TEM in the same manner as in Example 1, the amorphous fine particles having an average particle diameter of 50 nm or less inside the fiber and the length of the fiber outer peripheral part being 200 nm or less. It was observed that rod-shaped fine particles were present and connected to each other. The density of amorphous fine particles having an average particle diameter of 50 nm or less was 249 particles / (μm) ² , and the density of rod-shaped fine particles was 113 particles / (μm) ² .

[Example 3]
(1) Production of Conductive Yarn Consisting of Conductive Cellulose Fiber Material A copper (II) acetate monohydrate similar to that in Example 1 was added at a concentration of 20 g / y to a yarn consisting of the same cupra fiber as in Example 1. The impregnation treatment was carried out by introducing the yarn in a 25 ° C. water bath in which the same amount of liter and sodium hydroxide as in Example 1 were dissolved at a concentration of 9% by weight so that the residence time was 120 seconds. The impregnated yarn was subsequently placed in a 25 ° C. water bath in which the same sodium sulfide nonahydrate as in Example 1 was dissolved at a concentration of 40 g / liter and the same sodium hydroxide as in Example 1 was dissolved at a concentration of 9% by weight. The yarn was introduced so as to have a residence time of 120 seconds and subjected to a sulfidation reduction treatment. These impregnation treatment and sulfidation reduction treatment were repeated four times, and then washed sufficiently with water and dried with hot air at 110 ° C. to obtain a conductive yarn made of a conductive cellulose fiber material.

(2) Evaluation of conductive yarn made of conductive cellulose fiber material The initial elastic modulus, breaking elongation and breaking strength of the obtained conductive yarn were 201.8 MPa, 2.1% and 78.8 MPa, respectively. It was. The volume specific resistance value of the conductive yarn was 6.4 × 10 ⁻² Ω · cm. As to the weight of the copper sulfide contained in the conductive yarn, the same DTA-TG analysis as in Example 1 was performed up to about 600 ° C. As a result, the residual weight was 21% by weight. Moreover, when analyzed based on the photograph of the fiber cross section of the conductive yarn photographed by TEM in the same manner as in Example 1, the amorphous fine particles having an average particle diameter of 50 nm or less inside the fiber and the length of the fiber outer peripheral part being 200 nm or less. It was observed that rod-shaped fine particles were present and connected to each other. The density of amorphous particles having an average particle diameter of 50 nm or less was 528 particles / (μm) ² , and the density of rod-shaped fine particles was 240 particles / (μm) ² .

[Example 4]
(1) Production of Conductive Yarn Consisting of Conductive Cellulose-Based Fiber Material A copper (II) acetate monohydrate similar to that in Example 1 was added at a concentration of 40 g / y to the yarn consisting of the same cupra fiber as in Example 1. The impregnation treatment was carried out by introducing the yarn in a 25 ° C. water bath in which the same amount of liter and sodium hydroxide as in Example 1 were dissolved at a concentration of 9% by weight so that the residence time was 120 seconds. The impregnated yarn was subsequently placed in a 25 ° C. water bath in which the same sodium sulfide nonahydrate as in Example 1 was dissolved at a concentration of 40 g / liter and the same sodium hydroxide as in Example 1 was dissolved at a concentration of 9% by weight. The yarn was introduced so as to have a residence time of 120 seconds and subjected to a sulfidation reduction treatment. These impregnation treatment and sulfidation reduction treatment were repeated four times, and then washed sufficiently with water and dried with hot air at 110 ° C. to obtain a conductive yarn made of a conductive cellulose fiber material.

(2) Evaluation of conductive yarn made of conductive cellulose fiber material The initial elastic modulus, breaking elongation, and breaking strength of the obtained fiber were 218.6 MPa, 2.7%, and 104.5 MPa, respectively. The volume specific resistance value of the conductive yarn was 3.4 × 10 ⁻¹ Ω · cm. The appearance of the fibers of the conductive yarn was good and there were no yarn spots. FIG. 3 is a photograph of the fiber surface taken with an SEM. As shown in the photograph in FIG. 3, the deposited fine particles of copper sulfide are exposed, but it can be seen that the surface is smooth. With respect to the weight of copper sulfide contained in the conductive yarn, the same DTA-TG analysis as in Example 1 was performed up to about 600 ° C. As a result, the remaining weight was 28% by weight.

FIG. 4 is a photograph of the cross section of the conductive yarn fibers taken by TEM. As shown in FIG. 4, it was observed that amorphous fine particles having an average particle diameter of 50 nm or less inside the fiber and rod-like fine particles having a length of 200 nm or less at the outer periphery of the fiber were formed and connected to each other as the fine particles comprising copper sulfide. It was done. The density of amorphous fine particles having an average particle diameter of 50 nm or less was 743 particles / (μm) ² , and the density of rod-shaped fine particles was 337 particles / (μm) ² .

[Example 5]
(1) Production of Conductive Yarn Consisting of Conductive Cellulose Fiber Material A copper (II) acetate monohydrate similar to that in Example 1 was added at a concentration of 5 g / y to a yarn consisting of the same cupra fiber as in Example 1. The impregnation treatment was carried out by introducing the yarn in a 25 ° C. water bath in which the same amount of liter and sodium hydroxide as in Example 1 were dissolved at a concentration of 9% by weight so that the residence time was 120 seconds. The impregnated yarn was subsequently placed in a 25 ° C. water bath in which sodium sulfide nonahydrate as in Example 1 was dissolved at a concentration of 5 g / liter and sodium hydroxide as in Example 1 was dissolved at a concentration of 9% by weight. The yarn was introduced so as to have a residence time of 120 seconds and subjected to a sulfidation reduction treatment. These impregnation treatment and sulfidation reduction treatment were repeated four times, and then washed sufficiently with water and dried with hot air at 110 ° C. to obtain a conductive yarn made of a conductive cellulose fiber material.

(2) Evaluation of conductive yarn made of conductive cellulose fiber material The initial elastic modulus, breaking elongation, and breaking strength of the obtained fiber were 139.6 MPa, 2.7%, and 82.7 MPa, respectively. The volume specific resistance value of the conductive yarn was 7.3 × 10 ⁻¹ Ω · cm. As to the weight of copper sulfide contained in the conductive yarn, the same DTA-TG analysis as in Example 1 was performed up to about 600 ° C. As a result, the remaining weight was 5% by weight. Observation of the cross section of the conductive yarn fiber photographed with TEM revealed that fine particles made of copper sulfide were amorphous fine particles having an average particle diameter of 50 nm or less inside the fiber and rod-shaped fine particles having a fiber outer peripheral length of 200 nm or less. It was observed that they were connected to each other. The density of amorphous fine particles having an average particle diameter of 50 nm or less was 78 particles / (μm) ² , and the density of rod-shaped fine particles was 34 particles / (μm) ² .

[Example 6]
(1) Production of Conductive Yarn Consisting of Conductive Cellulose Fiber Material A copper (II) acetate monohydrate similar to that in Example 1 was added at a concentration of 5 g / y to a yarn consisting of the same cupra fiber as in Example 1. The impregnation treatment was carried out by introducing the yarn in a 25 ° C. water bath in which the same amount of liter and sodium hydroxide as in Example 1 were dissolved at a concentration of 9% by weight so that the residence time was 120 seconds. The impregnated yarn was subsequently placed in a 25 ° C. water bath in which sodium sulfide nonahydrate as in Example 1 was dissolved at a concentration of 10 g / liter and sodium hydroxide as in Example 1 was dissolved at a concentration of 9% by weight. The yarn was introduced so as to have a residence time of 120 seconds and subjected to a sulfidation reduction treatment. These impregnation treatment and sulfidation reduction treatment were repeated four times, and then washed sufficiently with water and dried with hot air at 110 ° C. to obtain a conductive yarn made of a conductive cellulose fiber material.

(2) Evaluation of conductive yarn made of conductive cellulose fiber material The initial elastic modulus, breaking elongation, and breaking strength of the obtained fiber were 161.2 MPa, 2.5%, and 80.5 MPa, respectively. The volume specific resistance value of the conductive yarn was 1.9 × 10 ⁻¹ Ω · cm. As to the weight of copper sulfide contained in the conductive yarn, the same DTA-TG analysis as in Example 1 was performed up to about 600 ° C. As a result, the remaining weight was 12% by weight.

As a result of observing a photograph of the cross section of the fiber of the conductive yarn photographed by TEM, as the fine particles made of copper sulfide, amorphous fine particles having an average particle diameter of 50 nm or less inside the fibers and rod-shaped fine particles having a length of the fiber outer periphery of 200 nm or less are obtained. It was observed that they were formed and connected to each other. The density of amorphous fine particles having an average particle diameter of 50 nm or less was 290 particles / (μm) ² , and the density of rod-shaped fine particles was 133 particles / (μm) ² .

[Example 7]
(1) Production of Conductive Yarn Consisting of Conductive Cellulose Fiber Material A copper (II) acetate monohydrate similar to that in Example 1 was added at a concentration of 5 g / y to a yarn consisting of the same cupra fiber as in Example 1. The impregnation treatment was carried out by introducing the yarn in a 25 ° C. water bath in which the same amount of liter and sodium hydroxide as in Example 1 were dissolved at a concentration of 9% by weight so that the residence time was 120 seconds. The impregnated yarn was subsequently placed in a 25 ° C. water bath in which the same sodium sulfide nonahydrate as in Example 1 was dissolved at a concentration of 20 g / liter and sodium hydroxide as in Example 1 was dissolved at a concentration of 9% by weight. The yarn was introduced so as to have a residence time of 120 seconds and subjected to a sulfidation reduction treatment. These impregnation treatment and sulfidation reduction treatment were repeated four times, and then washed sufficiently with water and dried with hot air at 110 ° C. to obtain a conductive yarn made of a conductive cellulose fiber material.

(2) Evaluation of conductive yarn made of conductive cellulose fiber material The initial elastic modulus, elongation at break and strength at break of the obtained fiber were 144.4 MPa, 2.2% and 71.3 MPa, respectively. The volume specific resistance value of the conductive yarn was 2.1 × 10 ⁻¹ Ω · cm. As to the weight of copper sulfide contained in the conductive yarn, the same DTA-TG analysis as in Example 1 was performed up to about 600 ° C. As a result, the remaining weight was 19% by weight. Observation of the cross section of the conductive yarn fiber photographed with TEM revealed that fine particles made of copper sulfide were amorphous fine particles having an average particle diameter of 50 nm or less inside the fiber and rod-shaped fine particles having a fiber outer peripheral length of 200 nm or less. It was observed that they were connected to each other. The density of amorphous fine particles having an average particle diameter of 50 nm or less was 525 particles / (μm) ² , and the density of rod-shaped fine particles was 236 particles / (μm) ² .

[Example 8]
(1) Production of Conductive Yarn Consisting of Conductive Cellulose-Based Fiber Material A copper (II) acetate monohydrate similar to that in Example 1 was added at a concentration of 40 g / y to the yarn consisting of the same cupra fiber as in Example 1. The impregnation treatment was carried out by introducing the yarn in a 25 ° C. water bath in which the same amount of liter and sodium hydroxide as in Example 1 were dissolved at a concentration of 9% by weight so that the residence time was 120 seconds. The impregnated yarn was subsequently placed in a 25 ° C. water bath in which sodium sulfide nonahydrate as in Example 1 was dissolved at a concentration of 10 g / liter and sodium hydroxide as in Example 1 was dissolved at a concentration of 9% by weight. The yarn was introduced so as to have a residence time of 120 seconds and subjected to a sulfidation reduction treatment. These impregnation treatment and sulfidation reduction treatment were repeated four times, and then washed sufficiently with water and dried with hot air at 110 ° C. to obtain a conductive yarn made of a conductive cellulose fiber material.

(2) Evaluation of conductive yarn made of conductive cellulose fiber material The initial elastic modulus, elongation at break and strength at break of the obtained fiber were 209.8 MPa, 3.6% and 143.8 MPa, respectively. The volume specific resistance value of the conductive yarn was 3.6 × 10 ¹ Ω · cm. As to the weight of copper sulfide contained in the conductive yarn, the same DTA-TG analysis as in Example 1 was performed up to about 600 ° C. As a result, the remaining weight was 3% by weight. Observation of the cross section of the conductive yarn fiber photographed with TEM revealed that fine particles made of copper sulfide were amorphous fine particles having an average particle diameter of 50 nm or less inside the fiber and rod-shaped fine particles having a fiber outer peripheral length of 200 nm or less. It was observed that they were connected to each other. The density of amorphous fine particles having an average particle diameter of 50 nm or less was 68 particles / (μm) ² , and the density of rod-shaped fine particles was 31 particles / (μm) ² .

[Example 9]
(1) Production of Conductive Yarn Consisting of Conductive Cellulose-Based Fiber Material A copper (II) acetate monohydrate similar to that in Example 1 was added at a concentration of 40 g / y to the yarn consisting of the same cupra fiber as in Example 1. The impregnation treatment was carried out by introducing the yarn in a 25 ° C. water bath in which the same amount of liter and sodium hydroxide as in Example 1 were dissolved at a concentration of 9% by weight so that the residence time was 120 seconds. The impregnated yarn was subsequently placed in a 25 ° C. water bath in which the same sodium sulfide nonahydrate as in Example 1 was dissolved at a concentration of 20 g / liter and sodium hydroxide as in Example 1 was dissolved at a concentration of 9% by weight. The yarn was introduced so as to have a residence time of 120 seconds and subjected to a sulfidation reduction treatment. These impregnation treatment and sulfidation reduction treatment were repeated four times, and then washed sufficiently with water and dried with hot air at 110 ° C. to obtain a conductive yarn made of a conductive cellulose fiber material.

(2) Evaluation of conductive yarn made of conductive cellulose fiber material The initial elastic modulus, breaking elongation, and breaking strength of the obtained fiber were 198.1 MPa, 2.5%, and 120.7 MPa, respectively. The volume specific resistance value of the conductive yarn was 2.0 × 10 ⁰ Ω · cm. As to the weight of copper sulfide contained in the conductive yarn, the same DTA-TG analysis as in Example 1 was performed up to about 600 ° C. As a result, the remaining weight was 11% by weight. Observation of the cross section of the conductive yarn fiber photographed with TEM revealed that fine particles made of copper sulfide were amorphous fine particles having an average particle diameter of 50 nm or less inside the fiber and rod-shaped fine particles having a fiber outer peripheral length of 200 nm or less. It was observed that they were connected to each other. The density of amorphous fine particles having an average particle diameter of 50 nm or less was 278 particles / (μm) ² , and the density of rod-shaped fine particles was 126 particles / (μm) ² .

[Example 10]
(1) Production of Conductive Yarn Consisting of Conductive Cellulose-Based Fiber Material A copper (II) acetate monohydrate similar to that in Example 1 was added at a concentration of 40 g / y to the yarn consisting of the same cupra fiber as in Example 1. The impregnation treatment was carried out by introducing the yarn in a 25 ° C. water bath in which the same amount of liter and sodium hydroxide as in Example 1 were dissolved at a concentration of 9% by weight so that the residence time was 120 seconds. The impregnated yarn was subsequently placed in a 25 ° C. water bath in which sodium sulfide nonahydrate as in Example 1 was dissolved at a concentration of 80 g / liter and sodium hydroxide as in Example 1 was dissolved at a concentration of 9% by weight. The yarn was introduced so as to have a residence time of 120 seconds and subjected to a sulfidation reduction treatment. These impregnation treatment and sulfidation reduction treatment were repeated four times, and then washed sufficiently with water and dried with hot air at 110 ° C. to obtain a conductive yarn made of a conductive cellulose fiber material.

(2) Evaluation of conductive yarn made of conductive cellulose fiber material The initial elastic modulus, breaking elongation and breaking strength of the obtained fiber were 199.4 MPa, 1.3% and 110.5 MPa, respectively. The volume specific resistance value of the conductive yarn was 1.3 × 10 ⁻¹ Ω · cm. As for the weight of copper sulfide contained in the conductive yarn, the same DTA-TG analysis as in Example 1 was performed up to about 600 ° C. As a result, the remaining weight was 25% by weight. Observation of the cross section of the conductive yarn fiber photographed with TEM revealed that fine particles made of copper sulfide were amorphous fine particles having an average particle diameter of 50 nm or less inside the fiber and rod-shaped fine particles having a fiber outer peripheral length of 200 nm or less. It was observed that they were connected to each other. The density of amorphous fine particles having an average particle diameter of 50 nm or less was 788 particles / (μm) ² , and the density of rod-shaped fine particles was 354 particles / (μm) ² .

  FIG. 5 shows the volume resistivity value and the concentration of copper (II) acetate monohydrate with respect to the conductive yarn when the combination of the concentrations of copper acetate and sodium sulfide obtained in Examples 1 to 10 is changed. The volume specific resistance value for the conductive yarn is shown in the case where is changed to 5 g / liter, 10 g / liter, and 20 g / liter. As shown in FIG. 5, the volume resistivity value tended to decrease as the concentration of sodium sulfide increased. This is consistent with the result that the residual weight of copper sulfide is increased and the density of rod-shaped fine particles is increased.

[Example 11]
For a yarn made of rayon fiber (manufactured by Kuraray Co., Ltd.), a copper (II) acetate monohydrate similar to that in Example 1 has a concentration of 10 g / liter and a sodium hydroxide similar to Example 1 has a concentration of 9% by weight. The impregnation treatment was carried out by introducing the yarn in a water bath at 25 ° C. dissolved in each step so that the residence time was 120 seconds. For the impregnated yarn, the sodium sulfide nonahydrate concentration in the same manner as in Example 1 was changed to 5 g / liter, 10 g / liter, 20 g / liter, 40 g / liter, 80 g / liter, and sodium hydroxide was changed. In each case, the sulphidic reduction treatment was carried out by introducing the yarn into a 25 ° C. water bath dissolved at a concentration of 9% by weight so that the residence time was 120 seconds. These impregnation treatment and sulfidation reduction treatment were repeated twice or four times, then washed sufficiently with water and dried with hot air at 110 ° C. to obtain a conductive yarn made of a conductive cellulose fiber material. The volume resistivity value of the obtained conductive yarn was in the range of 3 × 10 ⁻¹ Ω · cm to ² × 10 ² Ω · cm.

[Example 12]
For the yarn composed of the same rayon fiber as in Example 11, the same concentration of copper (II) acetate monohydrate as in Example 1 was 20 g / liter and the same concentration of sodium hydroxide as in Example 1 was 9% by weight. The impregnation treatment was carried out by introducing the yarn in a water bath at 25 ° C. dissolved in each step so that the residence time was 120 seconds. In the impregnated yarn, the concentration of sodium sulfide nonahydrate as in Example 1 was changed to 5 g / liter, 10 g / liter, 20 g / liter, 40 g / liter, 80 g / liter, 120 g / liter. Then, the concentration of sodium hydroxide was set to 9% by weight, and the solution was introduced into a 25 ° C. water bath so that the residence time was 120 seconds, and the sulfide reduction treatment was performed. These impregnation treatment and sulfidation reduction treatment were repeated twice or four times, then washed sufficiently with water and dried with hot air at 110 ° C. to obtain a conductive yarn made of a conductive cellulose fiber material. The volume resistivity value of the obtained conductive yarn was a value in the range of 2 × 10 ⁻¹ Ω · cm to 6 × 10 ⁰ Ω · cm. Observation of the fiber surface photographed by SEM revealed that the appearance of the fiber was good, there were no yarn spots, and copper sulfide particles were dispersed and deposited on the fiber surface.

  FIG. 6 is a graph showing the measurement results of the volume specific resistance value for the conductive yarn when the combination of the number of impregnation treatments and sulfidation reduction treatments and the concentration of sodium sulfide is changed. It was found that the volume resistivity value of the conductive yarn can be changed significantly by changing the concentration of sodium sulfide and the number of treatments.

[Example 13]
(1) Production of conductive fabric made of conductive cellulose fiber material Sodium hydroxide similar to that in Example 1 was dissolved at a concentration of 6% by weight in a fabric made of cupra fiber (manufactured by Asahi Kasei Fibers Co., Ltd.) 25 Then, the residence time was introduced into a water bath at 120 ° C. so that the residence time was 120 seconds, and then the residence time was kept in a water bath at 25 ° C. in which the same copper (II) acetate monohydrate as in Example 1 was dissolved at a concentration of 70 g / liter. Was introduced for 120 seconds to perform the impregnation treatment. The impregnated fabric was subsequently introduced into a 25 ° C. water bath in which the same sodium sulfide nonahydrate as in Example 1 was dissolved at a concentration of 80 g / liter so as to have a residence time of 120 seconds. went. These impregnation treatment and sulfidation reduction treatment were repeated 8 times, and then washed sufficiently with water and dried with hot air at 110 ° C. to obtain a conductive fabric made of a conductive cellulose fiber material.

(2) Evaluation of conductive fabric made of conductive cellulose fiber material The initial elastic modulus, elongation at break and strength at break of the obtained conductive fabric were 313.6 MPa, 6.6% and 25.8 MPa, respectively. It was. The volume resistivity value of the conductive fabric was 2.4 × 10 ¹ Ω · cm. As a result of performing DTA-TG analysis up to about 600 ° C. in the same manner as in Example 1 for the weight of copper sulfide contained in the conductive fabric, the residual weight was 12% by weight.

[Example 14]
(1) Production of conductive fabric made of conductive cellulose fiber material 25 ° C. in which sodium hydroxide similar to that of Example 1 was dissolved at a concentration of 6% by weight with respect to a fabric made of cupra fibers similar to Example 13. Was introduced into the water bath so that the residence time was 120 seconds, and then the same concentration of copper (II) acetate monohydrate as in Example 1 was added at a concentration of 70 g / liter and citric acid (manufactured by Nacalai Tesque Co., Ltd.). Impregnation treatment was performed by introducing into a 25 ° C. water bath dissolved at 10 g / liter so that the residence time was 120 seconds. The impregnated fabric was subsequently introduced into a 25 ° C. water bath in which the same sodium sulfide nonahydrate as in Example 1 was dissolved at a concentration of 80 g / liter so as to have a residence time of 120 seconds. went. These impregnation treatment and sulfidation reduction treatment were repeated 8 times, and then washed sufficiently with water and dried with hot air at 110 ° C. to obtain a conductive fabric made of a conductive cellulose fiber material.

(2) Evaluation of conductive fabric made of conductive cellulose fiber material The initial elastic modulus, elongation at break and strength at break of the obtained conductive fabric were 352.8 MPa, 16.6% and 28.7 MPa, respectively. It was. The volume resistivity value of the conductive fabric was 7.2 × 10 ⁰ Ω · cm.

[Example 15]
(1) Production of conductive fabric made of conductive cellulose fiber material 25 ° C. in which sodium hydroxide similar to that of Example 1 was dissolved at a concentration of 6% by weight with respect to a fabric made of cupra fibers similar to Example 13. Into the water bath, a residence time of 120 seconds was introduced, and subsequently copper (II) acetate monohydrate as in Example 1 had a concentration of 70 g / liter and citric acid as in Example 14 had a concentration of 30 g. The impregnation treatment was carried out by introducing into a 25 ° C. water bath dissolved at a rate of 120 liters / liter so that the residence time was 120 seconds. The impregnated fabric was subsequently introduced into a 25 ° C. water bath in which the same sodium sulfide nonahydrate as in Example 1 was dissolved at a concentration of 80 g / liter so as to have a residence time of 120 seconds. went. These impregnation treatment and sulfidation reduction treatment were repeated 8 times, and then washed sufficiently with water and dried with hot air at 110 ° C. to obtain a conductive fabric made of a conductive cellulose fiber material.

(2) Evaluation of conductive fabric made of conductive cellulose fiber material The initial elastic modulus, elongation at break and strength at break of the obtained conductive fabric were 588.0 MPa, 13.3% and 36.9 MPa, respectively. It was. The volume resistivity value of the conductive fabric was 4.3 × 10 ⁰ Ω · cm.

[Example 16]
(1) Production of conductive fabric made of conductive cellulose fiber material 25 ° C. in which sodium hydroxide similar to that of Example 1 was dissolved at a concentration of 6% by weight with respect to a fabric made of cupra fibers similar to Example 13. Into the water bath, a residence time of 120 seconds was introduced. Subsequently, the same copper (II) acetate monohydrate as in Example 1 had a concentration of 70 g / liter and the same citric acid as in Example 14 had a concentration of 50 g. The impregnation treatment was carried out by introducing into a 25 ° C. water bath dissolved at a rate of 120 liters / liter so that the residence time was 120 seconds. The impregnated fabric was subsequently introduced into a 25 ° C. water bath in which the same sodium sulfide nonahydrate as in Example 1 was dissolved at a concentration of 80 g / liter so as to have a residence time of 120 seconds. went. These impregnation treatment and sulfidation reduction treatment were repeated 8 times, and then washed sufficiently with water and dried with hot air at 110 ° C. to obtain a conductive fabric made of a conductive cellulose fiber material.

(2) Evaluation of conductive fabric made of conductive cellulose fiber material The initial elastic modulus, elongation at break and strength at break of the obtained conductive fabric were 313.1 MPa, 8.9% and 24.3 MPa, respectively. It was. The volume resistivity value of the conductive fabric was 2.9 × 10 ⁰ Ω · cm.

[Example 17]
(1) Production of conductive fabric made of conductive cellulose fiber material 25 ° C. in which sodium hydroxide similar to that of Example 1 was dissolved at a concentration of 6% by weight with respect to a fabric made of cupra fibers similar to Example 13. Into the water bath, a residence time of 120 seconds was introduced. Subsequently, the same copper (II) acetate monohydrate as in Example 1 had a concentration of 70 g / liter and the same citric acid as in Example 14 had a concentration of 70 g. The impregnation treatment was carried out by introducing into a 25 ° C. water bath dissolved at a rate of 120 liters / liter so that the residence time was 120 seconds. The impregnated fabric was subsequently introduced into a 25 ° C. water bath in which the same sodium sulfide nonahydrate as in Example 1 was dissolved at a concentration of 80 g / liter so as to have a residence time of 120 seconds. went. These impregnation treatment and sulfidation reduction treatment were repeated 8 times, and then washed sufficiently with water and dried with hot air at 110 ° C. to obtain a conductive fabric made of a conductive cellulose fiber material.

(2) Evaluation of conductive fabric made of conductive cellulose fiber material The initial elastic modulus, elongation at break and strength at break of the obtained conductive fabric were 536.4 MPa, 25.6% and 39.0 MPa, respectively. It was. The volume resistivity value of the conductive fabric was 2.7 × 10 ⁰ Ω · cm.

  FIG. 7 shows the relationship between the citric acid addition concentration obtained in Examples 13 to 17 and the volume resistivity of the conductive fabric. As shown in FIG. 7, the volume specific resistance tends to decrease as the concentration of citric acid increases.

[Example 18]
About the conductive fabric obtained in Example 13 to Example 17, the calorific value by energization was evaluated. FIG. 8 is a graph showing the relationship between the energization time (seconds) and the average temperature (° C.) of the fabric. It can be seen that the higher the concentration of citric acid, the higher the steady-state average temperature, and the shorter the time to reach the steady-state temperature. Moreover, in the steady state, the entire fabric is in a substantially uniform heat generation state, and even if the heat generation state is maintained for one hour, no change is observed in the conductive fabric, and the same conductivity as before the heat generation is maintained. It was confirmed that it has excellent heat resistance. Further, even when the conductive fabric was immersed in hot water at 70 ° C. for 12 hours, no particular change was observed, and the same conductivity as before immersion in hot water was provided.

[Comparative Example 1]
When impregnation treatment and sulfidation reduction treatment were performed in the same manner as in Example 1, the treatment was performed under the same conditions except that sodium hydroxide was not added. The initial elastic modulus, breaking elongation and breaking strength of the obtained yarn were 214.5 MPa, 8.9% and 180 MPa, respectively. The volume resistivity of the yarn was outside the detection limit.

  According to the present invention, a fiber material having excellent conductivity can be obtained, and a conductive cellulose fiber material having both heat resistance and hot water resistance can be produced by using a cellulose fiber material. In addition, the conductive cellulose fiber material can be manufactured in the fiber manufacturing process, and can be manufactured by post-processing of fibers, yarns, and fabrics, and the manufacturing cost can be kept low. The conductive cellulose fiber material produced according to the present invention is a heat-resistant, excellent heat-resistant water-charging material, charge-eliminating material, brush, sensor, electromagnetic shielding material, non-metallic electric wire for electronic circuits, planar heating element, It can be applied to a wide range of uses such as electronic materials.

Claims (6)

A swelling step of swelling a cellulose fiber material with an aqueous solution containing an alkali metal hydroxide at a swelling rate of 20% by mass to 300% by mass, and an aqueous solution in which a compound containing copper ions is dissolved at a concentration of 5 g / liter to 70 g / liter Impregnation step for impregnating copper ions into the outer periphery and inside of the cellulosic fiber material, and copper ions impregnated into the cellulosic fiber material with an aqueous solution in which a compound containing sulfide ions is dissolved at a concentration of 5 g / liter to 120 g / liter A sulfidation reduction step of producing a fine particle composed of rod-shaped copper sulfide having a length of 200 nm or less on the outer peripheral portion of the cellulosic fiber material and a fine particle composed of amorphous copper sulfide having an average particle diameter of 50 nm or less inside A method for producing a conductive cellulose fiber material. The said swelling process is a manufacturing method of the electroconductive cellulose fiber material of Claim 1 performed in parallel with the said impregnation process. The said impregnation process is a manufacturing method of the electroconductive cellulose fiber material of Claim 1 or 2 with which carboxylic acid with a density | concentration of 0 g / liter-70 g / liter is contained in aqueous solution. The volume resistivity obtained by the method for producing a conductive cellulose fiber material according to claim 1 is 1.0 × 10. ^-2 ~ 1.0 × 10 ² A conductive cellulosic fiber material having Ω · cm. A fabric comprising the conductive cellulose fiber material according to claim 4. A planar heating element comprising the fabric according to claim 5.