JP3948848B2 - Conductive cellulosic fiber - Google Patents

Description

【００５４】
【表２】

【００５５】
【表３】

【００５６】
上記の表１〜３の結果から、平均粒径が２００ｍμ以下の導電性カーボンブラック微粒子（ａ）であるカーボンブラック微粒子（ａ₁）と、上記の要件（ iii ａ）、（ iii ｂ）および（ iii ｃ）のうちの少なくとも１つの要件を満たす導電性活性炭粒子（ｂ）に相当する導電性活性炭粒子（ｂ₁）を、導電性セルロース系繊維を構成するセルロースに対して、合計で５〜７０重量％の割合で含有している実験番号３〜７の導電性セルロース系繊維は、その導電性能（比抵抗値）にばらつきが少なく、しかも湿度変化による導電性能のばらつきも少なく、どのような環境下においても、安定で均質な導電性能を有することがわかる。
【００５７】
それに対して、導電性カーボンブラック微粒子（ａ）であるカーボンブラック微粒子（ａ₁）のみを含有する実験番号１の導電性セルロース系繊維は、その導電性能（比抵抗値）にばらつきが大きいこと、しかも難燃剤で処理すると導電性能が大幅に低下する（比抵抗値が大幅に上昇する）ことがわかる。
また、導電性活性炭粒子（ｂ）である導電性活性炭粒子（ｂ₁）（活性炭粒子）のみを含有する実験番号１０の導電性セルロース系繊維は、難燃化処理していないものおよび難燃化処理したもののいずれにおいても導電性能のばらつきが大きく、満足のゆく導電性能を備えていないことがわかる。
【００５８】
また、２種の導電性粒子を含有する場合であっても、平均粒径が２００ｍμ以下の導電性カーボンブラック微粒子（ａ）と、上記の要件（ iii ａ）、（ iii ｂ）および（ iii ｃ）のうちの少なくとも１つの要件を備えている導電性活性炭粒子との組み合わせに該当しない、実験番号８および９の導電性セルロース系繊維では、難燃剤で処理すると導電性能の低下（比抵抗値の上昇）が生ずることがわかる。
【００５９】
【発明の効果】
本発明の導電性セルロース系繊維は、その導電性能（比抵抗値）にばらつきが少なく、均質な導電性能を有しており、しかも難燃剤で処理した後も導電性能の低下およびばらつきが抑制されていて良好な導電性と難燃性を兼ね備えている。
その上、本発明の導電性セルロース系繊維は、湿度の影響を受けにくく、湿度が変化してもその導電性能が変わらない。
そのため、本発明の導電性セルロース系繊維、特に難燃化処理を施してある本発明の導電性セルロース系繊維は、均質で且つ高い導電性能を有し、難燃性に優れており、しかも湿度非依存性であり、複写機などにおける帯電用ブラシ、除電用ブラシおよびクリーニングブラシをはじめとして各種の用途に有効に使用することができる。
特に、本発明の難燃化された導電性セルロース系繊維を用いて得られる帯電用ブラシでは、複写機の感光体層全域への均一な電荷の付与を円滑に行われるために斑などのない鮮明な複写物を形成させることができる。
そして、本発明の難燃化された導電性セルロース系繊維を用いて得られる除電用ブラシは、均一で良好な除電作用を有するために、複写の反復回数を重ねても、複写物に筋などの汚れが発生する現象が少ない。
また、本発明の難燃化された導電性セルロース系繊維を用いて得られるクリーニングブラシは、クリーニング効果に優れていることから、複写の反復回数を重ねても、複写物に筋などの汚れが発生する現象を低減することができる。
さらに、本発明の難燃化された導電性セルロース系繊維を用いて得られる帯電用ブラシ、除電用ブラシおよびクリーニングブラシは、複写機内の高温にさらされても発火、燃焼、熱変性などのトラブルが生じず、またドラム表面上の感光体層にピンホールに接触して電気的短絡状態（ショート現象）が発生した場合にも、発火、燃焼、変形などが生じにくい。
【図面の簡単な説明】
【図１】 導電性カーボンブラック微粒子および導電性活性炭粒子の体積固有抵抗値の測定法を示す概略図である。］
【符号の説明】
１ 塩化ビニル樹脂製のナット
２ａ 鉄製ボルト
２ｂ 鉄製ボルト[0001]
BACKGROUND OF THE INVENTION
  The present invention relates to a conductive cellulose fiber, a flame-retardant conductive cellulose fiber, and a charging brush, a static eliminating brush, and a cleaning brush using them. More specifically, the present invention relates to an electrophotographic recording type electrostatic copying machine or a copying machine also called a dry copying machine, a charging brush, a discharging brush and a cleaning brush used in a facsimile, a printer, etc. In addition, the present invention relates to a conductive cellulose fiber and a flame-retardant conductive cellulose fiber that can be effectively used in the brush.
[0002]
[Prior art]
  As is well known, an electrostatic copying machine uses a photosensitive semiconductor material (hereinafter sometimes referred to as a “photosensitive member”) that conducts electricity when exposed to light as an electrostatic image holding unit. . Specifically, (1) the photosensitive layer formed on the drum surface is uniformly charged with a positive charge by a charging device such as a charging brush or roller, and then (2) the original is irradiated with light. The reflected light is guided through the lens onto the photosensitive layer, and the charge on the photosensitive portion (white portion without characters or drawings in the original) disappears, and an electrostatic latent image is formed by the charge corresponding to the original. (3) In this state, toner is supplied onto the photoreceptor layer, and the toner is attached to the electrostatic latent image on the photoreceptor layer by static electricity to visualize the electrostatic latent image, and (4) the photoreceptor A visible image formed by the toner on the layer is transferred to paper and heated to fix the toner on the paper, and (5) the charge and toner remaining on the photoreceptor layer are removed with a static elimination brush, A copy is made in the cycle.
[0003]
  The above-described charging brush and charge eliminating brush used in the electrostatic copying machine are brushes for charging and discharging in contact with the photoreceptor layer, respectively. The thing which wound the pile fabric which consists of fibers, or the thing which stuck the pile fabric which consists of conductive fibers on the plate-like body is mentioned.
  In copiers, the temperature inside the machine becomes high due to the heating during fixing, so the conductive fibers used for the charging brush and static elimination brush should not be deformed even if subjected to heat for a long time in the copier. Is required.
  However, most general-purpose synthetic fibers such as polyester fibers, polyamide fibers, polyolefin fibers and the like are considered to be unsuitable for the required performance, and from this point, for example, JP-A-63-249185 As disclosed in Japanese Patent Laid-Open No. 4-289876, Japanese Patent Laid-Open No. 4-289877, Japanese Patent Publication No. 1-229887, etc., conductive regenerated cellulosic fibers that do not deform even when subjected to heat over a long period of time ( Hereinafter referred to as “cellulosic fibers”).
[0004]
  In the conductive cellulose fiber used for the charging brush, the specific resistance value is generally 10^Three-10⁸In the range of Ω · cm, it is desirable that the conductive cellulose fiber used for the static elimination brush has a specific resistance value of 10 in general.²-10^FourIt is desirable to be in the range of Ω · cm. Therefore, in the conductive cellulose fiber used for the charging brush or the static elimination brush, the addition rate of the conductive carbon particles as the conductivity-imparting substance is changed, or post-processing such as a hydrophobic treatment is performed (Japanese Patent Publication No. 1-229887). In general, it is generally performed to adjust the conductive performance to those suitable for each application.
  In that case, in the conductive cellulosic fiber, when the addition rate of the conductive carbon particles to the cellulose is sequentially increased from 0% by weight, the conductivity of the cellulosic fiber rapidly increases around a certain addition rate (ratio). In general, the phenomenon that the resistance value rapidly decreases) does not show a gradual increase in conductivity in which the conductivity of the cellulosic fibers gradually increases as the addition rate of the conductive carbon particles increases.
  For example, the specific resistance value of the cellulosic fiber is 10 when the addition rate of the conductive carbon particles is 15% by weight.⁹The Ω · cm was 10 when the addition rate of the conductive carbon particles was 17% by weight.^ThreeThe conductivity performance changes abruptly as it drops to Ω · cm.
[0005]
  Therefore, the conductive performance (specific resistance value, etc.) of the conductive cellulosic fiber is, for example, in the length direction of the fiber only by the amount of conductive carbon particles added being slightly changed during the manufacturing process of the conductive cellulosic fiber. It is extremely difficult to stably obtain cellulosic fibers having uniform conductive performance. And when a charging brush or a static elimination brush is manufactured using such conductive cellulose fibers having a variation in conductive performance, the charging brush or static elimination brush having a uniform conductive performance over the entire surface It becomes difficult to obtain a brush. In a charging brush having a variation in conductive performance, it is difficult to apply a uniform charge to the entire photoreceptor layer, and as a result, a copy tends to have spots lacking in clarity. In addition, the brush for static elimination having a variation in the conductive performance has a problem that it becomes impossible to avoid the phenomenon that stains such as streaks occur on the copy as the number of times of copying is repeated.
  From this point, the above-mentioned abrupt change in conductivity performance (abrupt decrease in specific resistance value) associated with a change (increase) in the addition rate of conductive carbon particles is alleviated, and there is no variation in conductivity performance. There was a need to obtain fibers.
[0006]
  In addition, the charging brush and the discharging brush used in the copying machine are strongly required to be flame retardant in addition to the above-described uniform conductive performance. In other words, in a copying machine, heating is performed when a visible image on a photoreceptor layer formed of toner is transferred and fixed on paper. However, if copying is performed for a long time, the amount of heat generated in the machine increases and the temperature in the machine increases. Due to the high temperature, the charging brush and the static elimination brush are required to be flame-retardant so that ignition, combustion, thermal denaturation and the like do not occur even at such a high temperature. Furthermore, if there is a pinhole in the photosensitive layer on the drum surface, an electrical short circuit (short phenomenon) may occur when the charging brush or the static elimination brush contacts the pinhole. It is required that the conductive cellulose fibers constituting the charging brush and the static elimination brush do not ignite or burn.
[0007]
  In addition, charging brushes and static elimination brushes used in copiers tend to cause disturbances in the initial image due to variations in conductive performance such as specific resistance values due to changes in the usage environment, particularly humidity. In view of this, there is a need for a charging brush and a static elimination brush that are not affected by environmental changes such as humidity.
[0008]
  Also, a cleaning brush used in a copying machine is generally used with a conductive performance because cleaning effect is improved if cleaning is performed while removing electricity. Therefore, in the case of cleaning brushes as well as in the case of charging brushes and static elimination brushes, the conductive performance has no variation, it is flame retardant, and even if the humidity changes, the conductive performance is greatly affected. If no fiber material is used, the cleaning effect is more excellent.
[0009]
Description of the invention
  The inventor of the present invention aims to eliminate the above-mentioned disadvantage of the large variation in the conductive performance due to the above-described rapid change (the rapid decrease in the specific resistance value) of the conductive performance due to the change (increase) in the addition rate of the conductive carbon particles. Have been studying. As a result, when two or more kinds of conductive fine particles having different specific resistance values are contained in the cellulose fiber, the gradient of the “conductive fine particle content ratio-specific resistance value curve” in the cellulose fiber becomes gentle. Even if the addition rate of the conductive fine particles in the cellulosic fiber varies somewhat, there is no sudden change in the conductive performance (specific resistance value) of the conductive cellulosic fiber, and the variation in specific resistance value is suppressed to within 103Ω · cm. As a result, it was found that conductive cellulosic fibers having uniform conductive performance can be obtained, and an application was made earlier (Japanese Patent Laid-Open No. 9-49116).
  In the case where a charging brush, a static eliminating brush and a cleaning brush are manufactured using the conductive cellulose fiber developed by the present inventors, the conductive performance (specific resistance value) between single fibers constituting the brush is reduced. Since there is little variation, the charge supply to the photoreceptor layer by the charging brush can be uniformly performed over the entire charged region, and a clear copy can be obtained. Since it is performed uniformly and the cleaning is performed well, there is an effect that stains such as streaks are hardly generated on the copy even if the number of times of copying is repeated.
[0010]
  Based on the above-described invention, the present inventors should develop conductive cellulose fibers that are excellent in flame retardancy and are not affected by the change in humidity, in addition to uniform conductive performance without variation. We have continued research. And in treating the said conductive cellulose fiber which does not have dispersion | variation in the electroconductive performance (specific resistance value) containing 2 or more types of electroconductive fine particles from which electroconductive performance (specific resistance value) differs, it makes it flame-retardant by processing with a flame retardant. As the two or more kinds of conductive particles added to the cellulosic fiber, conductive carbon black fine particles having a specific average particle size and conductive properties having a specific conductive performance, average particle size and / or shapeActivated carbonWhen conductive cellulose fibers are made by combining particles and adding them in a predetermined amount, even if the conductive cellulose fibers are treated with a flame retardant, deterioration and variation in conductive performance are suppressed, and humidity The present invention was completed by finding that a cellulosic fiber having good conductivity and flame retardancy can be obtained.
[0011]
  That is, the present invention
(I) Conductive carbon black fine particles (a) and conductiveActivated carbonA conductive cellulosic fiber containing particles (b);
(Ii) The conductive carbon black fine particles (a) are conductive carbon black fine particles having an average particle size of 200 mμ or less;
(Iii) ConductivityActivated carbonParticle (b) has the following requirements( iii a), ( iii b) and ( iii c)Conductivity that satisfies at least one of the requirementsActivated carbonParticles;
  ( iii a)The volume resistivity at a temperature of 20 ° C. and a humidity of 65% is 1.5 to 10 times that of the conductive carbon black fine particles (a);
  ( iii b)The average particle size is 300-2000 m;
  ( iii c)Having a polyhedral shape with ridge angles;
and,
(Iv) The conductive carbon black fine particles (a) and conductiveActivated carbonThe total content of the particles (b) in the cellulosic fibers is 5 to 70% by weight with respect to the cellulose constituting the cellulosic fibers;
It is an electroconductive cellulosic fiber characterized by this.
[0012]
  And this invention is an above-described electroconductive cellulose fiber formed by processing with a flame retardant.
[0013]
  Furthermore, the present invention provides a specific resistance value (R) after treatment with a flame retardant at a temperature of 20 ° C. and a humidity (RH) of 15 to 65%.₁) (Ω · cm) and flame resistance agent before treatment (R₀) (Ω · cm) ratio (R₁/ R₀) Is 10^ThreeTreat with flame retardant, which isMade of the aboveIt is a conductive cellulosic fiber. Hereinafter, the humidity in this specification means “RH”.
[0014]
  And this invention is the specific resistance value (R) in the low humidity (temperature 20 degreeC, humidity 15%) after the process by a flame retardant._L) (Ω · cm) and specific resistance (R) at high humidity (temperature 20 ° C, humidity 65%) after treatment with flame retardant_H) (Ω · cm) ratio (R_L/ R_H) Is 10^ThreeTreat with flame retardant, which isMade of the aboveIt is a conductive cellulosic fiber.
[0015]
  Furthermore, the present invention is a charging brush, a static elimination brush or a cleaning brush using any one of the above-described conductive cellulose fibers.
[0016]
DETAILED DESCRIPTION OF THE INVENTION
  The present invention is described in detail below.
  The “cellulosic fiber” in the present invention refers to fibers other than natural cellulosic fibers, and specific examples thereof include regenerated cellulose fibers such as viscose rayon, cupra (copper ammonia rayon), fortisan fibers, and cellulose nitrate fibers, and acetate. Examples thereof include semi-synthetic fibers such as fibers. Among them, viscose rayon and cupra are desirable because they do not deform the fiber form due to heat and are excellent in thermal stability.
[0017]
  As described above, the conductive cellulose fiber of the present invention contains conductive carbon black fine particles (a) having an average particle size of 200 mμ or less.
  The conductive carbon black fine particles (a) used in the present invention have an average particle size of 200 mμ or less, so that the conductive carbon black fine particles are uniformly dispersed in the cellulosic fiber, and the conductive performance varies. A cellulosic fiber with less content can be obtained.
  The conductive carbon black fine particles (a) used in the present invention preferably have an average particle size of 100 mμ or less, and more preferably 50 mμ or less.
[0018]
  As the conductive carbon black fine particles (a) used in the present invention, any carbon black fine particles having an average particle diameter of 200 mμ or less and conductive can be used, and among them, ASTM D2414- is not particularly limited. Conductive carbon black fine particles having a dibutyl phthalate (DBP) oil absorption measured according to 65T of 50 ml / 100 g or more are preferably used, and highly conductive carbon black fine particles having a DBP oil absorption of 200 ml / 100 g or more are more preferably used. It is done.
[0019]
  Further, as the conductive carbon black fine particles (a), those having an electric resistance value of 10 to 18 mΩ when the volume specific resistance value is measured under the conditions of a temperature of 20 ° C. and a humidity of 65% are preferably used. And those having a resistance of 11 to 15 mΩ are more preferably used. In addition, the “volume resistivity” in the present specification refers to a value measured by a measurement method described later.
[0020]
  Specific examples of the carbon black fine particles that can be used as the conductive carbon black fine particles (a) include “Ketjen Black EC” (trade name) (average particle size of 30 μm) manufactured by AKZO, “Ketjen Black EC600JD” ( (Trade name) (average particle size 30 mμ), “T-1375 Black (R) EC” (average particle size 30 mμ of carbon black fine particles), a conductive carbon black dispersion manufactured by Dainichi Seika Co., Ltd., Dainippon Ink & Chemicals, Inc. Examples thereof include “Visco Black 1195” (average particle diameter of carbon black fine particles of 50 mμ or less) which is a Ketchen Black dispersion manufactured by Co., Ltd. These conductive carbon black fine particles exhibit a volume resistivity value of 11.0 to 14.5 mΩ when measured under the above conditions.
  The conductive cellulose fiber of the present invention may contain only one kind of conductive carbon black fine particles having an average particle diameter of 200 mμ or less as the conductive carbon black fine particles (a), or two or more kinds. It may be.
[0021]
  As described above, the conductive cellulose fiber of the present invention has the following requirements:( iii a), (iii b) and ( iii c);
  ( iii a)The volume resistivity at a temperature of 20 ° C. and a humidity of 65% is 1.5 to 10 times that of the conductive carbon black fine particles (a);
  ( iii b)The average particle size is 300-2000 m;
  ( iii c)Having a polyhedral shape with ridge angles;
Conductivity that satisfies at least one of the requirementsActivated carbonContains particles (b).
  Conductivity used in the present inventionActivated carbonThe particles (b) have the above requirements( iii a), (iii b) and ( iii c)One of the above requirements, two requirements, or all of them may be satisfied, and preferably at least two requirements are satisfied. More preferably, all three requirements are met.
[0022]
  ConductivityActivated carbonAbove requirements for particles (b)( iii a)Has a volume resistivity value at a temperature of 20 ° C. and a humidity of 65% of not less than 1.5 times and not more than 10 times that of the conductive carbon black fine particles (a).Activated carbonMeans particles. ConductivityActivated carbonThe volume resistivity of the particles (b) is 2.3 to 7 times that of the conductive carbon black fine particles (a).Activated carbonParticles are preferred.
[0023]
  ConductivityActivated carbonRequirements described above as particles (b)( iii a)When using what satisfies (conductive performance), the cellulose fiber which does not have dispersion | variation in conductive performance can be obtained by using together with electroconductive carbon black microparticles | fine-particles (a) mentioned above. Moreover, although the reason is not clear, it is possible to prevent or suppress the decrease in conductivity performance and increase in dispersion even after treatment with a flame retardant, and it is possible to obtain a conductive cellulose fiber excellent in both conductivity and flame retardancy. .
[0024]
  Also conductiveActivated carbonThe above requirements as particles (b)( iii b)When using a material satisfying (average particle diameter of 300 to 2000 mμ), it is possible to obtain cellulosic fibers having no variation in conductive performance by using in combination with the conductive carbon black fine particles (a) described above. Although it is not clear, it is possible to obtain conductive cellulosic fibers excellent in both conductivity and flame retardancy with little decrease in conductive performance and increase in dispersion even after treatment with a flame retardant. In the present invention, conductivityActivated carbonAs the particles (b), conductivity having an average particle diameter of 500 to 2000 mμActivated carbonIt is preferable to use particles, and the conductivity is 600 to 1500 mμ.Activated carbonMore preferably, particles are used.
[0025]
  In general, the carbon black fine particles including the conductive carbon black fine particles (a) used in the present invention have a spherical or almost spherical shape having no ridge angle (pointed corners), or the spherical particles described above. Has a structure that is gathered in a tuft. In contrast, conductivityActivated carbonAbove requirements for particles (b)( iii c)Is the conductiveActivated carbonMeans that the particle (b) has a non-spherical polyhedral shape with ridges (pointed corners), and therefore requirements( iii c)Conductive withActivated carbonThe particles (b) are different from the conductive carbon black fine particles, which are generally spherical or aggregates thereof, and are different. ConductivityActivated carbonThe above requirements as particles (b)( iii c)Conductivity with (polyhedral shape with ridge angle)Activated carbonIn the case of using particles, by using in combination with the conductive carbon black fine particles (a) described above, it is possible to obtain cellulosic fibers having no variation in conductive performance, and after treatment with a flame retardant, although the reason is not clear However, it is possible to obtain conductive cellulosic fibers that are excellent in both conductivity and flame retardancy with little decrease in conductivity performance and increase in dispersion.
[0026]
  Conductivity used in the present inventionActivated carbonThe particles (b) have the above requirements( iii a), (iii b) and ( iii c)Conductivity that meets the requirements of at least one ofActivated carbonIf particlesYesMisalignment can also be used. Conductivity in the present inventionActivated carbonThe above-mentioned requirements that can be used as the particles (b)( iii a), (iii b) and ( iii c)Conductivity that meets the requirements of at least one ofActivated carbonAs particles, ExampleFor example, “CG”, “GS”, “4SA”, “GWC”, “KW”, “YP-17”, etc., which are activated carbons manufactured by Kuraray Chemical Co., Ltd. can be mentioned.
  As the activated carbon particles, those having a volume resistivity value of 25 to 100 mΩ when measured under conditions of a temperature of 20 ° C. and a humidity of 65% are preferably used, and those having a volume resistivity of 40 to 65 mΩ are more preferably used. .
  The conductive cellulosic fiber of the present invention has one type of conductivity.Activated carbonEven if it contains particles (b), or two or more types of conductivityActivated carbonThe particles (b) may be contained.
[0027]
  The conductive cellulose fiber of the present invention comprises conductive carbon black fine particles (a) and conductiveActivated carbonIt is necessary to contain the particles (b) in a ratio of 5 to 70% by weight (based on the weight of cellulose) with respect to the cellulose constituting the cellulosic fiber in the total of both, and 5 to 50% by weight. It is preferable to contain in the ratio. Conductive carbon black fine particles (a) and conductive in conductive cellulose fibersActivated carbonWhen the total content of the particles (b) is less than 5% by weight, the conductivity of the cellulosic fibers becomes low, and it becomes impossible to obtain conductive cellulosic fibers that can be used effectively in the production of charging brushes and static elimination brushes. . On the other hand, conductive carbon black fine particles (a) in cellulose fibers and conductivityActivated carbonWhen the total content of the particles (b) exceeds 70% by weight, single yarn breakage or the like occurs during the production of the conductive cellulosic fiber, resulting in poor fiberization process and a decrease in yarn physical properties. Therefore, troubles such as thread breakage occur during weaving. In addition, the conductivity of the conductive cellulose fiber becomes too high, and it becomes impossible to obtain a conductive cellulose fiber suitable for manufacturing a charging brush or a static elimination brush.
[0028]
  Furthermore, in the conductive cellulose fiber of the present invention, the conductive carbon black fine particles (a) and the conductiveActivated carbonIt is preferable that the content ratio of the particles (b) is 0 <(a) / (b) ≦ 139, in particular 0 <(a) / (b) ≦ 99, by weight ratio, whereby conductive cellulose fibers Is generally required for charging brushes and static elimination brushes.²-10⁸It becomes easy to make the range of Ω · cm, there is little variation in specific resistance value in the fiber length direction, and there is little variation or variation in specific resistance value even when treated with flame retardant, and humidity change etc. Thus, it is possible to stably obtain conductive cellulose fibers that are not affected by the environmental change and have excellent conductivity.
[0029]
  The fineness of the conductive cellulose fiber of the present invention is not particularly limited, and can be determined according to the use of the conductive cellulose fiber. In general, from the viewpoint of ease of production of conductive cellulose fibers, charging performance when used for charging brushes, static elimination brushes, cleaning brushes, etc., single fibers of conductive cellulose fibers The fineness is preferably 0.5 to 100 denier, and more preferably 1.0 to 50 denier.
[0030]
  The production method of the conductive cellulose fiber of the present invention is not particularly limited, and the conductive carbon black fine particles (a) and the conductiveActivated carbonAny method can be used as long as it is a method capable of smoothly producing conductive cellulose fibers containing particles (b) in a dispersed manner. Generally, in a spinning dope for producing cellulosic fibers Conductive carbon black fine particles (a) and conductiveActivated carbonA method of uniformly dispersing the particles (b) and spinning them according to a conventional method using the spinning solution is used to produce conductive cellulose fibers. Conductive carbon black fine particles (a) and conductiveActivated carbonIn mixing the particles (b) into the spinning dope, it is necessary to suppress their secondary aggregation. For this reason, for example, the prepared spinning dope (viscose undiluted solution, etc.) is strong under high speed rotation of 2500 rpm or more. The conductive carbon black fine particles (a) are gradually added while stirring, and then the conductivityActivated carbonAfter gradually adding the particles (b), a mixing operation or the like is preferably employed by further vigorously stirring for 30 minutes or more.
[0031]
  The above-described conductive cellulose fiber of the present invention is treated with a flame retardant to obtain a flame retardant conductive cellulose fiber.
  As the flame retardant, any of organic flame retardants and / or inorganic flame retardants conventionally used for flame retardant of cellulosic fibers can be used. For example, borax, boric acid, dibasic ammonium phosphate, ammonium sulfate, chloride Ammonium salts such as ammonium, phosphates, sodium tungstate, titanium chloride, antimony chloride, phosphorylamide, titanium oxide, antimony oxide, zinc oxide, sulfamate, aluminum hydroxide and other inorganic flame retardants, organic phosphorus-containing compounds, Examples thereof include organic flame retardants such as organic halogen-containing compounds, organic antimony compounds, and organic-containing nitrogen compounds. Of these, flame retardants composed of organic phosphorus-containing compounds are preferably used. Organic phosphorus-containing compound flame retardants include organic phosphorus-containing flame retardants composed only of phosphorus / carbon / oxygen / hydrogen, organic phosphorus-containing nitrogen-containing flame retardants, organic-containing flame retardants. Examples thereof include phosphorus-containing halogen flame retardants and organic phosphorus-containing nitrogen-containing halogen flame retardants.
[0032]
  Examples of flame retardants composed of organic phosphorus-containing compounds that can be used in the present invention include, but are not limited to, tetrakis (hydroxymethyl) phosphonium salt, aziridinyl phosphine oxide, urea-phosphoric acid mixture, N- Methylol dialkylphosphonopropionamide, vinyl phosphonate oligomer, combination of vinyl phosphonate oligomer with other monomers such as N-methylol acrylamide, 2,4-diamino-6-diethoxyphosphinyl-1,3 Triazine derivatives containing phosphorus as a substituent such as methylolated 5-triazine, haloalkyl phosphates such as tris (2,3-dibromopropyl) phosphate, tris (dichloroisopropyl) phosphate, triallyl phosphate, trihexyl phosphate, etc. Such as alkyl phosphates can be mentioned. In the present invention, one type of flame retardant or two or more types of flame retardant may be used.
[0033]
  The flame retardant treatment of the conductive cellulose fiber is carried out by adding a flame retardant in advance in the spinning dope when spinning the fiber and spinning it as a flame retardant fiber or by spinning the conductive cellulose fiber. Even if it is performed on a fiber, it may be performed on a product such as a charging brush or a neutralizing brush obtained using conductive cellulose fibers. Among these, it is preferable to perform the flame retardant treatment on the conductive cellulosic fibers before forming the brush from the viewpoint that the flame retardant can be uniformly attached to the fibers.
  The method and treatment conditions for the flame retardant treatment are not particularly limited, and can be carried out by a method conventionally employed for cellulosic fibers. For example, an aqueous dispersion containing a flame retardant, an aqueous solution, an organic solvent The method of apply | coating to a conductive cellulose fiber, the method of immersing a conductive cellulose fiber in the said liquid containing a flame retardant, etc. are employable. Among them, a method capable of performing a uniform treatment without treatment spots and performing a flame retardant treatment as a part of a fiber manufacturing process rather than performing individual treatments for flame retardant is desirable.
[0034]
  As an example of a flame retardant treatment method preferably employed, in the case of producing conductive cellulosic fibers using a Nelson type continuous spinning machine, after coagulation regeneration and water washing on a pair of scouring rollers, A method of applying a dispersion containing a flame retardant to a running yarn from which excess moisture has been removed by dehydration and then passing through a drying step can be exemplified. In this method, a flame retardant can be uniformly applied to fibers. . As the flame retardant-containing dispersion at that time, for example, an aqueous dispersion containing 10 to 30% by weight of a flame retardant and 2 to 5% by weight of a smoothing agent can be used. Examples of such a flame retardant-containing dispersion include a dispersion containing a flame retardant and an oil-based smoothing agent, and a dispersion containing a flame retardant and a surfactant. Specific examples include “Frame Guard 5316”. -S "(organic phosphorus-containing flame retardant; manufactured by Dainippon Ikin Chemical Industry Co., Ltd.) in an amount of 20 to 30% by weight and" Saffanol 503-D "(polyamine cationic surfactant; manufactured by Sanyo Chemical Co., Ltd.) 2-5% by weight of “Sunsofter NP-25” (polyhydric alcohol-based nonionic surfactant; manufactured by Nikka Chemical Co., Ltd.) and / or “Soft Oil E-2” (smooth agent; manufactured by Miyoshi Oil & Fats Co., Ltd.) 10 to 30 times the dispersion containing, “Nikka Fine S-200” (guanidine flame retardant; manufactured by Nikka Chemical Co., Ltd.) and / or “Apyros 430P” (flame retardant manufactured by Yoshimura Oil Chemical Co., Ltd.) "KE-4001", "KE-4002" (nonionic surfactant; manufactured by Takemoto Yushi Co., Ltd.), "CA-200} (polyamide cationic surfactant; manufactured by Shoken Chemical Co., Ltd.), etc. Examples thereof include dispersions containing one or more surfactants in a proportion of 2 to 5% by weight.
[0035]
  The amount of the flame retardant attached to the conductive cellulosic fiber can be adjusted according to the type of the flame retardant, the use of the conductive cellulosic fiber, etc., but in general, based on the weight of the conductive cellulosic fiber, It is preferable that the flame retardant adhesion amount is 6 to 20% by weight.
[0036]
  In the present invention, the above-mentioned conductive carbon black fine particles (a) in the cellulosic fiber and the conductivityActivated carbonBy containing the particles (b) in the above-mentioned specific proportion, when measured at a temperature of 20 ° C. and a humidity of 65%, 10²-10⁸It has a specific resistance value in the range of Ω · cm, and there is little variation in specific resistance value in the fiber length direction (normal variation is 10^ThreeConductive cellulosic fibers excellent in quality can be obtained.
  Moreover, even after the conductive cellulose fiber is treated with a flame retardant, there is little decrease or variation in the conductive performance, and generally at a temperature of 20 ° C. and a humidity of 15 to 65%, the specific resistance value (R after treatment with the flame retardant)₁) (Ω · cm) and specific resistance before treatment with flame retardant (R₀) (Ω · cm) ratio (R₁/ R₀) Is 10^ThreeIt becomes as follows.
  Further, the cellulose fiber after the flame retardant treatment of the present invention has a specific resistance value (R) at low humidity (temperature 20 ° C., humidity 15%)._L) (Ω · cm) and specific resistance (R) at high humidity (temperature 20 ° C, humidity 65%)_H) (Ω · cm) ratio (R_L/ R_H) Is 10^ThreeIt is a fiber that is less susceptible to electrical conductivity due to changes in humidity.
  Therefore, the conductive cellulosic fibers after being treated with the flame retardant of the present invention are used for charging brushes, static elimination brushes, cleaning brushes and the like in copying machines, taking advantage of the above-described good conductivity and flame retardancy. Can be used effectively.
[0037]
  When the conductive cellulose fiber of the present invention and the flame retardant conductive cellulose fiber are used as a charging brush and a static elimination brush, the shape and structure of the charging brush, the static elimination brush and the cleaning brush are particularly limited. Instead, it can have the same shape and structure as the charging brush, the static eliminating brush, and the cleaning brush made of conductive cellulose fibers that are conventionally known.
[0038]
【Example】
  Hereinafter, the present invention will be specifically described with reference to examples, but the present invention is not limited thereto. In the following examples, conductive carbon black fine particles and conductiveActivated carbonThe average particle diameter and volume resistivity of the particles, the specific resistance value of the conductive cellulose fiber, the dry strength and the dry elongation were measured by the following methods.
[0039]
[Conductive carbon black fine particles and conductiveActivated carbonAverage particle diameter]
  Using a particle size distribution measuring device “CAPA-500” manufactured by HORIBA, Ltd., the particle size distribution was measured by a permeation type sedimentation method particle size distribution measurement method (a method combining a high-speed centrifugal sedimentation method and a natural sedimentation method).
[0040]
[Conductive carbon black fine particles and conductiveActivated carbonParticle volume resistivity]
  Conductive carbon black fine particles and conductiveActivated carbonThe volume resistivity of the particles was measured as shown in FIG. That is, conductive carbon black fine particles or conductive material is applied to a vinyl chloride resin nut 1 (metric screw inner diameter 16 mm).Activated carbonAfter filling the particles, the steel bolts 2a and 2b are screwed in from both sides of the nut 1, and the steel bolts 2a and 2b are tightened until the steel bolts 2a and 2b do not move any further (until they move), at a temperature of 20 ° C. and a humidity of 65 % Resistance between the left and right iron bolts 2a, 2b was measured using a resistance measuring instrument (Hioki 3220mΩ HI TEST) manufactured by Hioki Co., Ltd. Or conductiveActivated carbonThe volume specific resistance value (mΩ) of the particles was used. At that time, the volume resistivity of the nut 1 made of vinyl chloride resin was blank. In this measurement, conductive carbon black fine particles and conductiveActivated carbonAs particles, conductive carbon black fine particles or conductiveActivated carbonAbout 0.25 g of the particles were dispersed in 200 cc of pure water, and then dried and solidified to make it easy to fill the nut 1.
[0041]
[Specific Resistance Value of Conductive Cellulose Fiber (ρ) (Ω · cm)]
  Twenty test pieces having a length of 10 cm were sampled at intervals of 5000 m along the length direction of the conductive cellulosic fibers. A resistance measuring machine “SM-8210 electrode” manufactured by Toa Denpa Kogyo Co., Ltd. was applied under a condition of a temperature of 20 ° C. and a humidity of 15% or 65% between the test pieces of 10 cm (between both ends). The electrical resistance value R (Ω) was measured using a “superinsulator”, and the specific resistance value (ρ) (Ω · cm) of 20 test pieces was determined by the following formula.
[0042]
[Expression 1]
        Specific resistance (ρ) (Ω · cm) = R × (S / L)
[In the formula, R is the electrical resistance value (Ω) of the test piece, and S is the cross-sectional area (cm²) And L indicate the length (10 cm) of the test piece. However, here, S = D / (900,000 × d) (D represents the total denier number of the conductive cellulose fiber as the weight (g), and d represents the density of the fiber (1.5 g / cm).^Three) ]
[0043]
[Dry strength and dry elongation of conductive cellulose fiber]
  Measured according to JIS L1013 (1992) “Testing method for chemical fiber filament yarn”.
[0044]
<< Reference Example 1 >> [Conductive carbon black fine particles (a₁) Preparation of dispersion]
  “Ketjen Black EC” (average particle size 30 mμ, temperature specific resistance value 11.3 mΩ, DBP oil absorption 360 ml / 100 g at a temperature of 20 ° C. and a humidity of 65%), which is a conductive carbon black fine particle manufactured by AKZO An aqueous dispersion in which a conductive dispersant (polyoxyethylene alkylamino ether) is added at a ratio of 25% by weight to the conductive carbon black fine particles and dispersed in water to a concentration of the conductive carbon black fine particles of 10% by weight. [Hereinafter referred to as “conductive carbon black fine particles (a₁) "Dispersion".
[0045]
Reference Example 2 [Conductive carbon black fine particles (a₂) Preparation of dispersion]
  Conductive carbon black dispersion "T-1375Black (R) EC" manufactured by Dainichi Seika Co., Ltd. (volume specific resistance value 14.4 mΩ at an average particle diameter of carbon black of 30 mμ, temperature of 20 ° C. and humidity of 65%) The same nonionic dispersant as used in Reference Example 1 was added at a ratio of 25% by weight to the conductive carbon black fine particles and dispersed in water so that the concentration of the conductive carbon black fine particles was 10% by weight. Aqueous dispersion [hereinafter referred to as “conductive carbon black fine particles (a₂) Dispersion ”.
[0046]
<< Reference Example 3 >> [ConductivityActivated carbonParticle (b₁) Preparation of dispersion]
  Activated carbon particles “YP-17” manufactured by Kuraray Chemical Co., Ltd."The same nonionic dispersant as that used in Reference Example 1 was applied to the activated carbon particles (average particle size 980 mμ, volume resistivity value 45.2 mΩ at a temperature of 20 ° C. and humidity 65%, polygonal shape having a ridge angle). And an aqueous dispersion having a concentration of the activated carbon particles of 25% by weight [hereinafter referred to as “conductivity”.Activated carbonParticle (b₁) Dispersion ”.
[0047]
Reference Example 4 [ConductivityActivated carbonParticle (b₂) Preparation of dispersion]
  Activated carbon particles “4SA” manufactured by Kuraray Chemical Co., Ltd. (average particle size 920mμIn addition, the nonionic dispersant same as that used in Reference Example 1 is 30% by weight with respect to the activated carbon particles in a volume resistivity of 44.5 mΩ at a temperature of 20 ° C. and a humidity of 65% and a polygonal shape having a ridge angle. And an aqueous dispersion having a concentration of the activated carbon particles of 25% by weight [hereinafter referred to as “conductivity”.Activated carbonParticle (b₂) Dispersion ”.
[0048]
  Conductive carbon black fine particles or conductive used in the dispersions prepared in Reference Examples 1 to 4 aboveActivated carbonThe physical properties of the particles are summarized as shown in Table 1 below.
[0049]
<< Example 1 >> [Production of Conductive Cellulose Fiber]
(1) Conductive carbon black fine particles (a) prepared in Reference Examples 1 to 4 above on viscose having a cellulose concentration of 8% by weight and an alkali concentration of 6%₁) Dispersion, conductive carbon black fine particles (a₂)dispersionliquid,ConductivityActivated carbonParticle (b₁) Dispersion and conductivityActivated carbonParticle (b₂) One or two of the dispersion liquids are electrically conductive carbon black fine particles and / or electrically conductive to cellulose.Activated carbonAddition was made so that the content of the particles would be the value shown in Table 2 below, followed by high-speed stirring at 2700 rpm for 30 minutes, followed by vacuum degassing to prepare spinning stock solutions of Experiment Nos. 1 to 10, respectively.
[0050]
(2) Using each of the spinning stock solutions of Experiment Nos. 1 to 10 obtained in the above (1), using a Nelson type continuous spinning machine, from a spinning nozzle having a hole diameter of 0.07 mm and a hole number of 25, 11 cc / min Spin bath (H₂SO_Four130 g / liter, ZnSO_Four16 g / liter, Na₂SO_Four250 g / liter), and the distance in the bath is 200 mm and the draw ratio is 15%. Subsequently, it is passed through a heated spinning bath at a temperature of 50 ° C. on a roller, and then washed with water at 40 ° C. on the same roller. Roller drying treatment was performed at 105 ° C., and the product was wound around cheese without burning at a speed of 100 m / min. In each of Experiment Nos. 1 to 10, 1.75 kg of conductive cellulose fiber having 120 denier / 25 filaments was obtained. .
[0051]
(3) Also, using each of the spinning stock solutions of Experiment Nos. 1 to 10 obtained in (1) above, using a Nelson type continuous spinning machine, from a spinning nozzle having a hole diameter of 0.07 mm and 25 holes, every minute Spinning bath with a temperature of 61 ° C. under discharge conditions of 11 cc / min (H₂SO_Four130 g / liter, ZnSO_Four16 g / liter, Na₂SO_Four250 mm / liter), and then a distance of 200 mm in the bath and a draw ratio of 15% were passed through a heated spinning bath at a temperature of 50 ° C. on a roller, followed by washing with water at 40 ° C. on the same roller. The pre-dehydrated running yarn is provided with a flame retardant-containing dispersion at a rate of about 1 cc / min / weight, and then subjected to roller drying at 105 ° C., at a speed of 100 m / min. A fire-retardant conductive cellulose fiber having a flame retardant deposition amount of 120 denier / 25 filament of 6% by weight in each of Experiment Nos. 1 to 10 was produced by winding it around cheese. As the flame retardant-containing dispersion, an organic phosphorus-containing flame retardant (Dainippon Ink Chemical Co., Ltd. “Frameguard 5316-S”) and a nonionic surfactant (Takemoto Yushi Co., Ltd. “KE-4002”). ) Was used.
[0052]
(4) The dry strength and dry elongation of each of the conductive cellulose fibers of Experiment Nos. 1 to 10 obtained in (2) above were measured by the method described above, and as shown in Table 2 below. .
  Moreover, about each conductive cellulose fiber of the experiment numbers 1-10 obtained by said (2), the specific resistance value (ohm * cm) in temperature 20 degreeC and 15% of humidity, temperature 20 degreeC, and humidity 65% When the specific resistance value (Ω · cm) was measured by the method described above, it was as shown in Table 3 below.
(5) In addition, the specific resistance value (Ω · cm) at a temperature of 20 ° C. and a humidity of 15% for each of the flame-retardant conductive cellulose fibers of Experiment Nos. 1 to 10 obtained in (3) above. In addition, the specific resistance value (Ω · cm) at a temperature of 20 ° C. and a humidity of 65% was measured by the method described above, and as shown in Table 3 below.
[0053]
[Table 1]

[0054]
[Table 2]

[0055]
[Table 3]

[0056]
  From the results shown in Tables 1 to 3, carbon black fine particles (a) which are conductive carbon black fine particles (a) having an average particle size of 200 mμ or less.₁) And the above requirements( iii a), ( iii b) and ( iii c)Conductivity that meets the requirements of at least one ofActivated carbonConductivity corresponding to particle (b)Activated carbonParticle (b₁) Is contained in a ratio of 5 to 70% by weight in total with respect to the cellulose constituting the conductive cellulose fiber, the conductive cellulose fiber of Experiment Nos. 3 to 7 has its conductive performance (specific resistance value). ), And there is little variation in conductive performance due to changes in humidity. It can be seen that the conductive performance is stable and homogeneous under any environment.
[0057]
  In contrast, carbon black fine particles (a) which are conductive carbon black fine particles (a)₁The conductive cellulose fiber of Experiment No. 1 containing only) has a large variation in its conductive performance (specific resistance value), and when it is treated with a flame retardant, the conductive performance is greatly reduced (the specific resistance value is greatly reduced). You can see that it rises).
  Also conductiveActivated carbonConductivity of particles (b)Activated carbonParticle (b₁) The conductive cellulosic fiber of Experiment No. 10 containing only (activated carbon particles) has a large variation in the conductive performance in both the non-flame retardant and the fire retardant treated and satisfactory conductive performance. It turns out that it is not equipped.
[0058]
  In addition, even when two kinds of conductive particles are contained, the conductive carbon black fine particles (a) having an average particle diameter of 200 mμ or less and the above-described requirements( iii a), ( iii b) and ( iii c)Conductivity with at least one of the requirementsActivated carbonIt can be seen that the conductive cellulosic fibers of Experiment Nos. 8 and 9 that do not correspond to the combination with the particles cause a decrease in conductive performance (increase in specific resistance value) when treated with a flame retardant.
[0059]
【The invention's effect】
  The conductive cellulosic fiber of the present invention has little variation in its conductive performance (specific resistance value), has a homogeneous conductive performance, and even after being treated with a flame retardant, deterioration and variation in conductive performance are suppressed. And has both good conductivity and flame retardancy.
  In addition, the conductive cellulosic fiber of the present invention is hardly affected by humidity, and its conductivity performance does not change even when the humidity changes.
  Therefore, the conductive cellulosic fiber of the present invention, particularly the conductive cellulosic fiber of the present invention that has been subjected to a flame retardant treatment, has a homogeneous and high conductive performance, is excellent in flame retardancy, and is humidity. It is independent and can be used effectively in various applications including charging brushes, static elimination brushes and cleaning brushes in copying machines.
  In particular, in the charging brush obtained using the flame-retardant conductive cellulose fiber of the present invention, uniform charge is smoothly applied to the entire photoreceptor layer of the copying machine, so there are no spots. A clear copy can be formed.
  The static elimination brush obtained by using the flame-retardant conductive cellulose fiber of the present invention has a uniform and good static elimination action. There is little phenomenon that stains occur.
  In addition, the cleaning brush obtained using the flame-retardant conductive cellulose fiber of the present invention has an excellent cleaning effect, so that even if the number of times of copying is repeated, stains such as streaks appear on the copy. The phenomenon that occurs can be reduced.
  Further, the charging brush, the static eliminating brush and the cleaning brush obtained by using the flame-retardant conductive cellulose fiber of the present invention are free from troubles such as ignition, combustion and thermal denaturation even when exposed to high temperature in the copying machine. In addition, even when an electrical short circuit (short phenomenon) occurs due to contact with a pinhole in the photoreceptor layer on the drum surface, ignition, combustion, deformation, and the like are unlikely to occur.
[Brief description of the drawings]
FIG. 1 Conductive carbon black fine particles and conductivityActivated carbonIt is the schematic which shows the measuring method of the volume specific resistance value of particle | grains. ]
[Explanation of symbols]
1 Nut made of vinyl chloride resin
2a Iron bolt
2b Iron bolt

Claims (10)

(I) a conductive cellulose fiber containing conductive carbon black fine particles (a) and conductive activated carbon particles (b);
(Ii) The conductive carbon black fine particles (a) are conductive carbon black fine particles having an average particle size of 200 mμ or less;
(Iii) The conductive activated carbon particles (b) are conductive activated carbon particles that satisfy at least one of the following requirements ( iiia ), (iiib ), and ( iiic ) ;
( Iii a) The volume resistivity value at a temperature of 20 ° C. and a humidity of 65% is 1.5 to 10 times that of the conductive carbon black fine particles (a);
(Iii b) the average particle diameter is 300～2000Emumyu;
Having a polyhedral shape with a (iii c) an edge angle;
and,
(Iv) The total content of the conductive carbon black fine particles (a) and the conductive activated carbon particles (b) in the cellulosic fibers is 5 to 70% by weight with respect to the cellulose constituting the cellulosic fibers;
Conductive cellulosic fibers characterized by the above. The content ratio of the conductive carbon black fine particles (a) and the conductive activated carbon particles (b) in the conductive cellulose fiber is 0 <(a) / (b) ≦ 139 in terms of weight ratio. The conductive cellulose fiber described in 1.   3. The conductive cellulose fiber according to claim 1, wherein the conductive carbon black fine particles (a) are conductive carbon black fine particles having a DBP (dibutyl phthalate) oil absorption of 50 ml / 100 g or more.   The conductive carbon black fine particles (a) are conductive carbon black fine particles having a volume resistivity of 10 to 18 mΩ when measured at a temperature of 20 ° C and a humidity of 65%. The conductive cellulose fiber according to Item. The conductive activated carbon particles (b) is, when measured at a temperature 20 ° C. and a humidity of 65%, its volume resistivity, any one of claims 1 to 4, which is a conductive activated carbon particles 25~100mΩ The conductive cellulose fiber described in 1. The conductive cellulose fiber according to any one of claims 1 to 5 , wherein the conductive cellulose fiber is treated with a flame retardant. The cellulosic fiber according to claim 6 , wherein the flame retardant is a flame retardant comprising an organic phosphorus-containing compound. Ratio of specific resistance value (R ₁ ) (Ω · cm) after treatment with flame retardant and specific resistance value (R ₀ ) (Ω · cm) before treatment with flame retardant at a temperature of 20 ° C. and a humidity of 15 to 65% The conductive cellulose fiber according to claim 6 or 7, wherein (R ₁ / R ₀ ) is 10 ³ or less. Specific resistance value (R _L ) (Ω · cm) at low humidity (temperature 20 ° C, humidity 15%) after treatment with flame retardant and high humidity (temperature 20 ° C, humidity 65%) after treatment with flame retardant The conductive cellulose fiber according to any one of claims 6 to 8 , wherein a specific resistance value (R _H ) (Ω · cm) ratio (R _L / R _H ) is 10 ³ or less. Charging brush made of a conductive cellulosic fibers according to any one of claims 1 to 9 for charge removal brush or cleaning brush.

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