JP5131934B2 - Method for producing flame-retardant conductive yarn and flame-retardant conductive yarn produced by the production method - Google Patents

Description

TECHNICAL FIELD The present invention relates to a method for producing a flame-retardant conductive yarn having excellent conductivity and flame retardancy, and a flame-retardant conductive yarn produced by the production method.

Conventionally, as a conductive yarn that can obtain conductive performance, a yarn in which a metal is plated on the surface of a fiber, a yarn in which a conductive substance such as a metal, a metal compound, or carbon black is kneaded into a polymer has been proposed. . These methods are widely used in many industrial fields because they are relatively inexpensive and suitable for mass production. For example, such a conductive yarn is used as a charging or neutralizing brush used in an electrostatic copying machine. However, in a copying machine or the like, the temperature in the machine becomes high due to heating at the time of fixing. Therefore, it is required that conductive yarns used for these applications do not deform even when subjected to heat for a long time. Furthermore, since the internal temperature of electronic equipment becomes very high, internal parts of electronic equipment may burn, and high flame retardancy has been demanded. In addition, flame resistance is also required for conductive yarns used in static elimination brushes.

In these applications, most general-purpose synthetic fibers such as acrylic fibers, polyester fibers, and polyamide fibers cannot be used due to insufficient heat resistance and form stability at high temperatures. As described in Documents 1 to 3, brushes using conductive cellulosic fibers have been proposed. However, the required flame retardancy has not yet been addressed. Furthermore, an attempt has been made to subject the conductive yarn to a flame retardant treatment by coating the surface of the conductive yarn used for the brush with a flame retardant, but the conductive yarn subjected to the conventional flame retardant treatment as described above is, Since the electric resistance value fluctuates, the desired conductive performance cannot be satisfactorily satisfied. As a result, there is a problem that the quality of the conductive brush is deteriorated and the copying function is defective.
Japanese Patent Laid-Open No. 4-289766 Japanese Patent Laid-Open No. 4-289877 Japanese Patent Publication No. 1-229887

The present invention has been made in view of such a technical background, and has stable conductivity, good flame retardancy, excellent productivity, and relatively inexpensive production. It aims at providing the manufacturing method of a flame-retardant conductive yarn which can be produced, and the flame-retardant conductive yarn manufactured by the manufacturing method.

As a result of intensive studies to solve such problems, the present inventors have made a conductive yarn having stable conductivity by reacting cellulosic fibers with a conductive polymer precursor in a gas phase state. As a result, it was found that by adding a flame retardant, a conductive yarn having good flame retardancy can be obtained, and the present invention has been achieved. In order to achieve the above object, the present invention provides the following means.

[1] In the method for producing a flame-retardant conductive yarn made of cellulosic fiber, an adhesion step of adhering a treatment liquid containing a flame retardant, a dopant, an oxidizing agent, and a binder resin to at least the surface of the cellulosic fiber. And contacting the cellulosic fiber to which the treatment liquid adheres with a conductive polymer precursor in a gas phase to coat at least a part of the surface of the cellulosic fiber with the conductive polymer. A method for producing a flame-retardant conductive yarn characterized by

[2] In the method for producing a flame-retardant conductive yarn made of cellulosic fiber, an adhesion step of adhering a treatment liquid containing a dopant, an oxidizing agent, and a binder resin to at least the surface of the cellulosic fiber; Contacting the cellulosic fiber with a conductive polymer on at least a part of the surface of the cellulosic fiber by bringing the cellulosic fiber to which the treatment liquid is attached into contact with the gas-phase conductive polymer precursor; And a step of attaching a flame retardant by dipping treatment.

[3] The method for producing a flame-retardant conductive yarn according to claim 1 or 2, wherein the conductive polymer precursor is one or more monomers selected from pyrrole, aniline, and thiophene.

[4] In the treatment liquid, the dopant content is 0.1 to 10% by mass, the oxidizing agent content is 0.1 to 10% by mass, and the binder resin content is 0.01 to 2.0% by mass. The method for producing a flame-retardant conductive yarn according to any one of claims 1 to 3.

[5] By applying the treatment liquid to at least the surface of the cellulose fiber using a roll coater, 0.2 to 20 parts by mass of the solid content of the treatment liquid is adhered to 100 parts by mass of the cellulose fiber. The method for producing a flame-retardant conductive yarn according to any one of claims 1 to 4.

[6] By bringing the cellulose-based fiber to which the treatment liquid is attached into contact with a conductive polymer precursor in a gas phase state, 0.2 to 5 parts by mass of a conductive polymer with respect to 100 parts by mass of the cellulose-based fiber. The method for producing a flame-retardant conductive yarn according to any one of claims 1 to 5, which is adhered.

[7] The method for producing a flame-retardant conductive yarn according to any one of [1] to [6], wherein an aromatic sulfonic acid is used as the dopant and a persulfate is used as the oxidizing agent.

[8] A flame-retardant conductive yarn having a surface resistance value of less than 1010 Ω / □ produced by the production method according to any one of claims 1 to 7.

In the invention of [1], the cellulosic fiber containing the dopant, the oxidant, and the binder resin, to which the treatment liquid is attached, is brought into contact with the conductive polymer precursor in a gas phase state, whereby the treatment liquid and the gas are brought into contact with each other. The conductive polymer precursor in the phase state reacts and the conductive polymer is coated on at least a part of the surface of the cellulosic fiber, so that the conductive polymer precursor is oxidatively polymerized, and reliable conductive performance is achieved. Can be obtained. In addition, if the cellulosic fiber has a treatment liquid containing a dopant, an oxidant, and a binder resin attached to at least the surface of the yarn, the conductive polymer can be firmly fixed, and stable conductivity can be obtained. Can be obtained as a flame-retardant conductive yarn.

In addition, since it includes an adhesion step in which a treatment liquid containing a flame retardant is adhered to at least the surface of the cellulose fiber, the flame retardant penetrates the cellulose fiber and has a good flame retardancy. A flammable conductive yarn can be obtained.

In addition, the flame retardant is included in the treatment liquid, and the flame retardant treatment is performed at the same time in the adhesion process in which the treatment liquid is adhered to at least the surface of the cellulosic fiber. The manufacturing method is high.

In the invention of [2], the cellulosic fiber containing the dopant, the oxidant, and the binder resin, to which the treatment liquid is attached, is brought into contact with the conductive polymer precursor in a gas phase state, so that the treatment liquid and the gas are brought into contact with each other. The conductive polymer precursor in the phase state reacts and the conductive polymer is coated on at least a part of the surface of the cellulosic fiber, so that the conductive polymer precursor is oxidatively polymerized, and reliable conductive performance is achieved. Can be obtained. In addition, if the cellulosic fiber has a treatment liquid containing a dopant, an oxidant, and a binder resin attached to at least the surface of the yarn, the conductive polymer can be firmly fixed, and stable conductivity can be obtained. Can be obtained as a flame-retardant conductive yarn.

Moreover, since the step of adhering the flame retardant to the cellulosic fiber by dipping treatment is included, it becomes possible to select the flame retardant as appropriate, and the flame retardant penetrates the cellulosic fiber and is good. It becomes possible to set it as the flame-retardant conductive yarn which has a flame retardance.

In the invention of [3], in the invention of the above, since the conductive polymer precursor in the gas phase state is one or more monomers selected from pyrrole, aniline, and thiophene, it is conductive to any fiber. Can be granted.

In the invention of [4], the dopant content in the treatment liquid is 0.1 to 10% by mass, the oxidant content is 0.1 to 10% by mass, and the binder resin content is 0.01 to 2%. Since it is 0.0 mass%, it is possible to bond the conductive polymer to the yarn while maintaining high production efficiency of the conductive polymer, thereby obtaining a conductive yarn having a reliable conductive performance.

In the invention of [5], by applying the treatment liquid to at least the surface of the yarn using a roll coater, 0.2 to 20 parts by mass of the solid content of the treatment liquid is adhered to 100 parts by mass of the yarn. It can be set as the electrically conductive thread | yarn with the soft texture maintained.

In the invention of [6], the conductive polymer is adhered to 0.2 to 5 parts by mass with respect to 100 parts by mass of the yarn by bringing the yarn attached with the treatment liquid into contact with the conductive polymer precursor in a gas phase. Therefore, sufficient conductive performance can be ensured, and a conductive yarn having softness of the yarn can be obtained.

In the invention of [7], since aromatic sulfonic acid is used as the dopant and persulfate is used as the oxidizing agent, the liquid stability is improved in a wider pH range from the acidic region to the alkaline region, and the conductive polymer is used. It is possible to obtain a flame retardant conductive yarn coated more uniformly.

[8] Since it is manufactured by the manufacturing method according to any one of items 1 to 7, it has good flame retardancy and has a surface resistance value of less than 10 ¹⁰ Ω / □, so that it is sufficiently antistatic. It becomes a flame retardant conductive yarn with performance.

The flame-retardant conductive yarn according to the present invention has excellent conductivity and flame retardancy, and the method for producing the flame-retardant conductive yarn attaches a treatment liquid to at least the surface of the cellulosic fiber. An adhesion step, and a step of coating a conductive polymer on at least a part of the surface of the cellulosic fiber to which the treatment liquid is adhered. At the same time, flame retardant treatment can be performed. Alternatively, a flame retardant treatment with a flame retardant can be performed in a separate step.

The cellulosic fibers according to the present invention include ordinary rayon fibers that are viscose rayon, polynosic rayon, cupra fibers that are copper ammonia rayon, regenerated cellulosic fibers such as lyocell fibers that are solvent-spun cellulose fibers, cotton, hemp, etc. Natural fiber and so on. Preferred are regenerated cellulosic fibers such as viscose rayon and polynodge rayon. By comprising only these fibers, the problem of environmental pollution can be reduced because it is biodegradable even if discarded.

The fineness of the fiber is 0.5 to 20 dtex, preferably 1 to 8 dtex. When the fineness is lowered, the conductive performance is improved, but the productivity is lowered, so that it is disadvantageous in terms of cost, 0.5 dtex or more is preferable, and if it exceeds 20 dtex, the conductive performance is insufficient. The fiber length is not particularly limited. The yarn shape is made by spinning to a thickness suitable for the application.

The treatment liquid according to the present invention is preferably a treatment liquid containing a dopant and an oxidizing agent, or a treatment liquid containing a dopant, an oxidizing agent, and a binder resin, and the dopant and the oxidizing agent are dissolved in a solvent. An emulsion liquid in which a binder resin (dispersoid) forms an emulsion with a dispersion medium is used, and a preferable solvent is water.

The dopant is a substance for improving the conductivity of the conductive polymer precursor and is not particularly limited. For example, p-toluenesulfonic acid, benzenesulfonic acid, naphthalenesulfonic acid, dodecylbenzenesulfonic acid, sulfone is used. And aromatic sulfonic acids such as modified polystyrene.

The oxidizing agent is a substance for oxidative polymerization of the conductive polymer precursor, and is not particularly limited. For example, ammonium persulfate, iron chloride (trivalent), iron sulfate (trivalent), hydrogen peroxide , Ammonium perborate, copper chloride (divalent), and the like. Also, a ferric salt of sulfonic acid used as a dopant (for example, a ferric salt of paratoluenesulfonic acid) can be used as an oxidizing agent.

The binder resin is not particularly limited. For example, vinyl resins represented by homopolymers or copolymers such as vinyl chloride, vinyl acetate, vinylidene chloride, acrylic resins, polyester resins, polyurethane resins, epoxy resins, Examples thereof include polyamide resins, fluororesins, and modified resins thereof.

In the treatment liquid, the dopant content is set to 0.1 to 10% by mass, the oxidizing agent content to 0.1 to 10% by mass, and the binder resin content to 0.01 to 2.0% by mass. Is preferred. By setting the content ratio in such a range, in the subsequent polymerization step, the conductive polymer having sufficient conductive performance can be obtained by sufficiently adhering the conductive polymer to the cellulosic fiber while maintaining high production efficiency of the conductive polymer. It can be.

The first invention in the present invention is characterized in that the treatment liquid contains a flame retardant. By containing the flame retardant in the treatment liquid, the flame retardant penetrates into the cellulosic fiber, and a flame retardant conductive yarn having good flame retardancy can be obtained. Moreover, it is not necessary to perform a flame retardant treatment in a separate process, and the production method is highly efficient.

The flame retardant may be a phosphorus flame retardant (red phosphorus, reactive phosphorus compound, etc.), a halogen flame retardant (including a combination of antimony trioxide), water, as long as the organic polymer material can be made flame retardant. Japanese metal flame retardants (aluminum hydroxide particles, magnesium hydroxide, etc.) can be used. The cellulosic fiber can be made into a yarn having good flame retardancy because the flame retardant is easily impregnated inside the fiber as compared with general-purpose synthetic fibers such as acrylic fiber, polyester fiber, and polyamide fiber.

In particular, phosphorus-based flame retardants are effective flame retardants for flame retardant organic polymer materials composed of cellulose carbon, hydrogen, and oxygen. For example, a flame retardant containing a reactive phosphorus compound as a main component has a dehydration and carbonolysis action that draws oxygen and hydrogen from cellulose material and the like when the flame comes into contact, and furthermore, it is difficult to generate polyphosphoric acid to cover the material surface. Flame retardant and impart flame retardancy to the material. Usually, it is said that flame retardancy is imparted to cellulose with an addition amount of about 15% by mass.

According to a second aspect of the present invention, the flame retardant treatment with the flame retardant is performed in a separate step. By carrying out in a separate step, the type of flame retardant can be selected as appropriate. The order of the steps can be before or after the attaching step for attaching the treatment liquid to at least the surface of the cellulosic fiber. A flame retardant and a binder resin can be applied by dipping or the like, and can be fixed by drying and heat treatment. As in the case of the first invention, the flame retardant to be used is a phosphorus flame retardant (red phosphorus, reactive phosphorus compound, etc.), a halogen flame retardant (three) as long as the organic polymer material can be made flame retardant. Hydrated metal flame retardant (aluminum hydroxide particles, magnesium hydroxide, etc.) can be used, and phosphorus flame retardant is particularly preferred.

The method for adhering the treatment liquid to at least the surface of the cellulosic fiber is not particularly limited, and examples thereof include application by a roll coater or spray. Especially, it is preferable to make 0.2-20 mass parts of solid content of a process liquid adhere with respect to 100 mass parts of said cellulose fibers by apply | coating at least the surface of the said cellulose fibers using a roll coater. By using a roll coater, a smaller amount of solid content can be uniformly and selectively attached to the surface region of the cellulosic fiber, thereby obtaining sufficient conductivity while ensuring the softness of the conductive yarn. be able to.

Next, as a method of covering at least a part of the surface of the cellulosic fiber with a conductive polymer, for example, a cheese treated with a treatment liquid is wound around a cheese bobbin to form cheese. The cheese bobbin may be a known one used when dyeing cheese. From inside the cheese bobbin, the conductive polymer precursor in a gas phase passes through the wound yarn layer or is wound around the cheese bobbin. A structure in which a conductive polymer precursor in a gas phase passes from the outside of the thread layer to the inside of the cheese bobbin is preferable. In addition, it is efficient to form the cheese by immediately and continuously winding the yarn treated with the treatment liquid around the cheese bobbin, but at this time the cheese is dried while being air-dried so that no excess treatment liquid remains on the yarn. It is desirable to wind it around a bobbin.

Next, the conductive polymer precursor in a gas phase is circulated and brought into contact with the cheese-like yarn in which the yarn treated with the treatment liquid is wound around the cheese bobbin. As this apparatus, for example, as shown in FIG. 1, a reaction chamber 1, a cheese stand 4, a circulation pump 7, a circulation pipe 5 (suction side, discharge side), and a conductive polymer precursor in a gas phase state. An apparatus composed of the adding apparatus 6 is mentioned. The cheese-like thread 3 wound around the cheese bobbin 2 is set on the cheese stand 4, the reaction chamber 1 is made airtight, and a conductive polymer precursor in a gas phase is generated from the addition device 6, and the circulation pump 7 To circulate the air in the reaction chamber 1 and the circulation pipe 5. By carrying out like this, like the arrow shown to a figure, the conductive polymer precursor of a gaseous-phase state circulates through a thread layer from the inside of cheese. At this time, a conductive yarn in which at least a part of the surface of the yarn is coated with the conductive polymer can be obtained by contacting and polymerizing the treatment liquid attached to the surface region of the yarn and the conductive polymer precursor. . Further, in order to coat the conductive polymer more uniformly, it is more preferable to perform the treatment by circulating the airflow by changing the direction of the circulating airflow in the forward and reverse directions.

The conductive polymer precursor is preferably a compound having a 5-membered aromatic heterocyclic structure or an aniline structure. Examples of the compound having a 5-membered aromatic heterocyclic structure partially or entirely include pyrrole and thiophene. Moreover, an aniline is mentioned as a compound which has an aniline structure in part or the whole. Of these, pyrrole is more preferred.

Moreover, in the addition apparatus of the conductive polymer precursor of a gaseous state, it is preferable to vaporize by setting a conductive polymer precursor to 10-40 degreeC. For example, the boiling point of pyrrole monomer at atmospheric pressure is 130 ° C., but it vaporizes in air even at temperatures below 130 ° C. until the saturated vapor pressure is reached. For this reason, a liquid pyrrole container may be placed in the addition apparatus and vaporized naturally, or bubbled with an inert carrier gas such as nitrogen to supply the vaporized pyrrole to the air in the reaction chamber and circulation pipe for circulation. You may make it make it. The gas phase polymerization reaction of the conductive polymer precursor is carried out until the oxidizing agent is consumed in the yarn to which the treatment liquid adheres, and stops spontaneously. This gas phase polymerization reaction takes about 1 to 30 minutes, although it depends on the amount of yarn processed with the processing solution sprinkled with cheese.

In the polymerization step, the conductive polymer is in a ratio of 0.2 to 5 parts by mass with respect to 100 parts by mass of the cellulosic fiber by bringing the yarn attached with the treatment liquid into contact with the conductive polymer precursor in a gas phase. It is preferable to adhere with. When the amount is 0.2 parts by mass or more, a conductive yarn having a surface resistance value of less than 10 ¹⁰ Ω / □ and sufficient antistatic performance can be obtained, and when the amount is 5 parts by mass or less, the yarn is soft. Can be secured. Among them, it is particularly preferable to attach the conductive polymer at a ratio of 0.5 to 3 parts by mass with respect to 100 parts by mass of the cellulose fiber.

Next, the cheese-like conductive yarn obtained in this manner is taken out from the cheese stand, dried in the cheese shape, washed with water to remove remaining free dopants, and further subjected to a drying treatment, whereby cheese is obtained. A conductive yarn having a shape can be obtained, and a large amount of flame-retardant conductive yarn can be produced at one time.

Next, specific examples of the present invention will be described, but the present invention is not particularly limited to these examples. Various performance evaluations were performed as follows. <Surface Resistance Value> The surface resistivity level of the conductive yarn was evaluated using a surface resistance measuring instrument (four probe method; JIS K7194). <Flame Retardancy> Flame retardance was evaluated according to a vertical combustion test (UL VW-1 combustion test). The judgment criteria were those satisfying the following three criteria. 1. Combustion due to after flame should not exceed 60 seconds. 2. The display flag must not burn more than 25%. 3. The cotton at the bottom does not burn due to falling objects

<Example 1> An aqueous treatment solution was applied to the surface of 165 dtex / 48f viscose rayon yarn using a roll coater. As the aqueous treatment liquid, 1% by mass of phosphoric ester amide (flame retardant), 1% by mass of ammonium persulfate (oxidant), 1% by mass of paratoluenesulfonic acid (dopant), polyester resin (binder resin) An aqueous solution containing 1% by mass was used. In this aqueous treatment liquid, ammonium persulfate and paratoluenesulfonic acid are dissolved in water, while the polyester resin is a dispersoid and forms an emulsion with water as a dispersion medium. Since 10 parts by mass of the aqueous treatment liquid per 100 parts by mass of the polyester multifilament yarn (original) was applied by the roll coater, the solid content of the aqueous treatment liquid per 100 parts by mass of the viscose rayon yarn (ammonium persulfate) , P-toluenesulfonic acid, polyester resin) was 0.3 parts by mass.

Next, the viscose rayon yarn to which the treatment liquid was adhered was wound around a cheese bobbin while squeezing it with mangles to obtain 2 kg of cheese. Next, this cheese is installed on the cheese stand of the apparatus of FIG. 1, covered and sealed, the pyrrole liquid is vaporized in the addition apparatus, the circulation pump is turned, and the air in the reaction chamber and the circulation pipe is changed. It was circulated. The circulation direction was changed every 30 seconds, and the pyrrole was vapor-phase polymerized by circulating for 10 minutes, so that at least a part of the surface of the viscose rayon yarn was coated with polypyrrole. Thereafter, the cheese-shaped viscose rayon yarn with attached polypyrrole is taken out from the cheese stand, dried in a cheese shape at 120 ° C. for 5 minutes, washed with water to remove remaining free dopants, and further dried ( 5 minutes at 120 ° C.) to obtain a cheese-shaped flame-retardant conductive yarn.

Next, the yarn was pulled out from the cheese, and the yarn was collected every time the roll diameter of the cheese decreased by 5 mm, and the surface resistance value was measured. In the outer layer, the middle layer, and the inner layer of cheese, the surface resistance value of the middle layer tends to be slightly higher than that of the inner and outer layers, but the difference is less than 10 ³ Ω / □ and 10 ⁶ to 10 ⁷ Ω / □. It was. The flame retardancy was acceptable.

<Example 2> Using a roll coater, an aqueous treatment liquid is applied to the surface of a 165 dtex / 48f viscose rayon yarn having 1% by weight of a reactive phosphorus compound (flame retardant) attached thereto by dipping treatment. And applied. As the aqueous treatment liquid, an aqueous solution containing 1% by mass of ammonium persulfate (oxidant), 1% by mass of paratoluenesulfonic acid (dopant), and 1% by mass of polyester resin (binder resin) was used. In the same manner as in Example 1, a flame-retardant conductive yarn was obtained. The surface resistance value was 10 ³ to 10 ⁵ Ω / □. The flame retardancy was also acceptable.

<Example 3> An aqueous treatment solution was applied to the surface of 165 dtex / 48f viscose rayon yarn using a roll coater. As the aqueous treatment liquid, an aqueous solution containing 1% by mass of ammonium persulfate (oxidant), 1% by mass of paratoluenesulfonic acid (dopant), and 1% by mass of polyester resin (binder resin) was used. A conductive yarn was prepared in the same manner as in Example 1, and 1% by mass of a reactive phosphorus compound (flame retardant) was attached to the surface of the conductive yarn by dipping treatment to obtain a flame retardant conductive yarn. The surface resistance value was 10 ³ to 10 ⁵ Ω / □. The flame retardancy was also acceptable.

<Example 4> A flame-retardant conductive yarn was obtained in the same manner as in Example 1 except that 50 parts by mass of an aqueous treatment liquid per 100 parts by mass of viscose rayon yarn was applied by application with a roll coater. The surface resistance value was 10 ³ to 10 ⁵ Ω / □. The flame retardancy was also acceptable.

<Example 5> A flame-retardant conductive yarn was obtained in the same manner as in Example 1 except that 100 parts by mass of the aqueous treatment liquid was adhered to 100 parts by mass of the viscose rayon yarn by application with a roll coater. The surface resistance value was 10 ³ to 10 ⁴ Ω / □. The flame retardancy was also acceptable.

<Example 6> A flame-retardant conductive yarn was obtained in the same manner as in Example 1 except that 5 parts by mass of an aqueous treatment liquid was applied per 100 parts by mass of the viscose rayon yarn by coating with a roll coater. The surface resistance value was 10 ⁸ to 10 ⁹ Ω / □. The flame retardancy was also acceptable.

<Example 7> A flame-retardant conductive yarn was obtained in the same manner as in Example 1 except that 150 parts by mass of an aqueous treatment liquid per 100 parts by mass of the viscose rayon yarn was applied by application with a roll coater. The surface resistance value was 10 ³ to 10 ⁴ Ω / □. The flame retardancy was also acceptable.

<Comparative example 1> In Example 1, 1 mass% of ammonium persulfate (oxidizer), 1 mass% of paratoluenesulfonic acid (dopant), and 1 mass% of polyester resin (binder resin) were contained as an aqueous treatment liquid. A conductive yarn was obtained in the same manner as in Example 1 except that an aqueous solution was used. The surface resistance value was 10 ⁵ to 10 ⁷ Ω / □. Further, the flame retardancy was also rejected.

It is the schematic which shows one Embodiment of the manufacturing process of the electrically conductive yarn which concerns on this invention.

DESCRIPTION OF SYMBOLS 1 ... Reaction chamber 2 ... Cheese bobbin 3 ... Cheese (thread layer) 4 ... Cheese stand 5 ... Circulation pipe 6 ... Addition device 7 ... Circulation pump

Claims (8)

In the method for producing a flame-retardant conductive yarn made of cellulosic fiber, an adhesion step of adhering a treatment liquid containing a flame retardant, a dopant, an oxidant, and a binder resin to at least the surface of the cellulosic fiber; and Including contacting the cellulose-based fiber with the treatment liquid with a conductive polymer precursor in a gas phase to coat at least a part of the surface of the cellulosic fiber with the conductive polymer. A method for producing a flame-retardant conductive yarn. In the method for producing a flame-retardant conductive yarn made of cellulosic fiber, an adhesion step of adhering a treatment liquid containing a dopant, an oxidizing agent, and a binder resin to at least the surface of the cellulosic fiber; and A step of coating the cellulosic fiber with a conductive polymer by contacting the adhering cellulosic fiber with a conductive polymer precursor in a gas phase, and dipping treatment on the cellulosic fiber. And a step of adhering a flame retardant to the flame retardant conductive yarn. The method for producing a flame-retardant conductive yarn according to claim 1 or 2, wherein the conductive polymer precursor is one or more monomers selected from pyrrole, aniline, and thiophene. In the treatment liquid, the dopant content is 0.1 to 10% by mass, the oxidizing agent content is 0.1 to 10% by mass, and the binder resin content is 0.01 to 2.0% by mass. Item 4. The method for producing a flame-retardant conductive yarn according to any one of Items 1 to 3. 2. The solid content of the treatment liquid is adhered to 0.2 to 20 parts by mass with respect to 100 parts by mass of the cellulosic fibers by applying the treatment liquid to at least the surface of the cellulosic fibers using a roll coater. 5. The method for producing a flame-retardant conductive yarn according to any one of items 1 to 4. Claims in which 0.2 to 5 parts by mass of a conductive polymer is attached to 100 parts by mass of the cellulose-based fiber by bringing the cellulose-based fiber to which the treatment liquid is attached into contact with a conductive polymer precursor in a gas phase. Item 6. A method for producing a flame-retardant conductive yarn according to any one of Items 1 to 5. The method for producing a flame-retardant conductive yarn according to any one of claims 1 to 6, wherein an aromatic sulfonic acid is used as the dopant and a persulfate is used as the oxidizing agent. A flame-retardant conductive yarn having a surface resistance value of less than 10 ¹⁰ Ω / □ produced by the production method according to claim 1.

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