JPH0949117A - Conductive cellulose fiber - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a conductive cellulose fiber having slight variation in specific resistance and suitable for an impression brush or an electricity removing brush in a dry-type copying machine of electrophotography, etc., by compounding carbon particles and zinc in fibers each in a specific amount. SOLUTION: A conductive cellulose fiber having the variation of a specific resistance of <100<3> Ωcm is obtained by compounding 5-70wt.% (preferably, 10-30wt.%) of carbon particles and 30-5000ppm of zinc in cellulose fibers. A copy figure drawn by an impression brush using the fiber as piles is excellent in sharpness.

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to a conductive cellulosic fiber. More specifically, the present invention relates to a conductive cellulosic fiber suitable as a pile fiber of an application brush or a static elimination brush used in a dry copying machine, a facsimile, a printer, etc. of an electrophotographic recording system.

[0002]

2. Description of the Related Art Conductive fibers containing a conductive filler such as carbon black and fine metal powder are relatively inexpensive and suitable for mass production, and thus are widely used in many industrial fields. In particular, in recent years, the use in electrophotographic recording type dry copying machines, facsimiles, and printers, which have rapidly spread, has been expanding. Behind this, there is a need for environmental protection measures for these copying machines and the like due to the recent increasing awareness of environmental protection.

In particular, the non-contact type corona charging method for charging the electrostatic image holding portion, that is, the photoconductor, which has been generally used in these devices up to now, has come to the point where harmful ozone generated during charging is generated. This is a big problem, and while the improvement of ozone filters that collect generated ozone is advancing, a contact charging method using a roller has been developed as a charging method that does not generate ozone, and that method has become widely adopted. There is.

After that, as one of the contact charging methods, a brush charging method which has been conventionally used only for removing static electricity is further advanced to develop a technology for newly applying charging brushes. Now, the contact charging method is a roller charging method. And the charging method by the application brush.

Here, the principle of the copying machine will be touched upon in order to facilitate understanding of the following description. Inside the copier, a copy is formed through the following steps. In the first step, the entire surface of a thin semiconductor layer, which is called the photoconductor, which is the electrostatic image holding section, is charged by corona discharge without contact from the tip of the metal wire, or by contact roller charging brush application. It is uniformly charged by the method. In the second step, the original is irradiated with light, and the light reflected from the original is imaged on the photoconductor through the lens. By this operation, the photoconductor part exposed to the light causes a current to flow and the charge disappears. , An electrostatic latent image is formed by charges corresponding to the original. In the third step, the toner is brought close to the electrostatic latent image and the toner moves to the photoconductor to visualize the electrostatic latent image. In the fourth step, the image formed by the toner on the photoconductor is transferred to the paper and heated to permeate and fix the toner between the fibers of the paper. In the fifth step, a series of operations is repeated, such as removing charges and toner remaining on the photoconductor with a cleaning brush to prepare for the next copy.

Therefore, the applied brush is a brush for contact charging instead of the non-contact corona discharge, and the cleaning brush is a cleaning brush used in the fifth step, and both have a conductive property on the roller surface. It is a member formed by winding a pile woven fabric composed of the fibers that it has.

Roughly speaking, the specific resistance value of the pile fibers is required to be in the range of 10 ⁵ to 10 ⁸ Ωcm for application brushes, and 10 ² to for static elimination brush applications.
It appears that a range of values of 10 ⁴ Ωcm has been sought.
Further, the pile structure is required to have a uniform pile density and pile length, have good uprightness, and not easily deform due to heat generated in the machine during long-term use. Most of the general-purpose synthetic fibers that have been thermoplastic so far for such required performance are not suitable for this application, and are disclosed in JP-A-63-249185 and JP-A-04-2.
89876, Japanese Patent Application Laid-Open No. 04-289877,
Regenerated cellulose fibers have been used as seen in Japanese Patent Publication No. 1-29887.

However, conventional conductive cellulose fibers have been obtained by post-processing such as hydrophobization as disclosed in, for example, Japanese Patent Publication No. 1-29887 to obtain conductive regenerated cellulose fibers having a predetermined specific resistance value. However, although it was manageable even though it was problematic in a static elimination brush application where the resistance value was simply low, each fiber forming the pile became an electrode, and there was a difference in the conductive performance of itself as much as possible. However, it is not always sufficient for an applied brush whose required characteristics are uniform, and in some cases, the variation width may reach 10 ⁵ Ωcm.

Therefore, in the applied brush using the conventional conductive regenerated cellulose fibers, the electrostatic latent image formed by the electric charges formed as a result of focusing the reflected light from the original on the photoconductor is not always clear. It's hard to say, and of course, the copy obtained from it was only obscure,
Moreover, as the number of times of copying was repeated, strong lines appeared on the copy surface, which could not be solved.

[0010]

SUMMARY OF THE INVENTION It is an object of the present invention to provide a novel conductive cellulosic fiber which has a small variation in the specific resistance value of the fiber and is suitable for an applied brush or a static elimination brush.

[0011]

[Means for Solving the Problems] That is, the present invention provides a conductive cellulose system containing 5% by weight or more and 70% by weight or less of conductive carbon particles in a fiber and 30 ppm or more and 5000 ppm or less of zinc. It is a fiber.

The details of the present invention will be described below. The variation in the specific resistance value of the fibers is greatly affected by the dispersed state of the conductive carbon particles, which is generated when the conductive cellulosic fibers are spun, that is, the aggregation unevenness. It can also be understood from the fact that the conductivity of fibers containing conductive carbon particles is generally expressed by the formation of chains of carbon particles dispersed in the fibers.

However, this agglomeration unevenness is caused by shock agglomeration when a uniform suspension of conductive carbon particles is added to viscose which is a strongly alkaline (PH13 or more) spinning stock solution, and its relatively high viscosity ( It was difficult to eliminate completely because it was caused by difficulty of dispersion for about 40 poise).

Therefore, paying attention to the fact that the metal particles impart the conductive performance, the effect of zinc used in the fiber manufacturing process of the regenerated cellulose fiber on the conductive performance of the final fiber was investigated in detail. As a result, it was found that when carbon particles and zinc coexisted within the range of numerical values in the fiber, the conductivity level was stabilized and showed a great effect in reducing the variation, and better still, the mechanical strength of the fiber was improved. In producing the conductive cellulosic fiber, the invention of the conductive cellulosic fiber was devised by devising a technique of leaving this zinc in the fiber and a technique of actively adding it.

The details of these behaviors are not understood, but they are considered as follows. It is presumed that even if the chain is broken due to the agglomeration unevenness of the dispersed carbon particles, which mainly controls the conductivity of the fiber, the zinc is present between them to compensate and maintain the conductivity.

The carbon particles mentioned here are, for example, AKZ.
Ketjen Black EC which is a conductive carbon black manufactured by O company (oil absorption 360 ml / 100 g, particle diameter 30 m
μ) and Ketjen Black EC600JD (oil absorption 36
0 ml / 100 g, particle size 30 mμ, or in some cases, as a black colorant, manufactured by Mitsubishi Kasei Co., Ltd., high-quality color black # 2600 (oil absorption 80 ml / 100 g, particle size 13 mμ) and intermediate color black # 1000 (oil absorption 55 ml / 100 g, particle size 18 mμ), or T of conductive carbon black dispersion paste manufactured by Dainichiseika
-1375 Black (R) EC and carbon black in a dispersion liquid which has already been dispersed and prepared by a pigment manufacturer, such as T-510 Black, which is a carbon dispersion paste as a black colorant.

Further, as a parameter generally indicating the conductivity level of conductive carbon black, the DBP oil absorption (= dibutylphthalate oil absorption, A of the ASTM test method) is used.
STM D2414-65T) is used, and it is a well-known fact in the art that the higher the value of these, the higher the conductivity of the carbon black. Or it may be measured by the method for measuring the electrical conductivity of carbon black in the Carbon Black Handbook <Carbon Black Association Edition, P507 (1971) Book Publisher>.

In the case of viscose rayon, zinc contained in the fiber is diffused into the fiber from a coagulation bath containing zinc in the process of forming the fiber through a semipermeable membrane of cellulose formed on the surface of the fiber. Zinc that is the result of leaving the required amount of the substance reacted with xanthate in the fiber, or zinc that has been previously dissolved or evenly dispersed in the spinning dope, is the zinc that is the result of controlling the residual amount in the fiber manufacturing process. There will be.

The production method of such a conductive cellulosic fiber is as follows, taking a viscose rayon yarn as an example. AKZO is added to viscose, which is a spinning solution with a cellulose concentration of 8% by weight and an alkali concentration of 6% by weight.
25 wt% of nonionic dispersant polyoxyethylene alkylamino ether and water were added to Ketjen Black EC, a conductive carbon manufactured by the same company, and water was added and mixed to prepare an aqueous dispersion containing 10 wt% of the carbon. To add this conductive carbon aqueous dispersion so that the carbon particles are contained in cellulose in an amount of, for example, 18% by weight,
Determine the amount of added dispersion according to the following calculation formula, gradually add the measured dispersion to the prepared viscose, at the same time,

W = V × Cc / 100 × B / 100 ÷ Bc / 100 W: Additive carbon particle dispersion liquid weight Kg V: Viscose weight Kg Cc: Cellulose concentration of viscose wt% B: Carbon addition ratio to cellulose Weight % Bc: Carbon particle concentration of added carbon particle dispersion liquid% by weight

The mixture prepared by stirring at 3000 rpm for 30 minutes is degassed in vacuum to obtain a spinning dope. The viscose thus obtained was subjected to a pore size of 0.0 using a Nelson continuous spinning machine.
11 cc / min from a spinning nozzle with 7 mm and 25 holes
Minute discharge condition, H ₂ SO ₄ 130g / l, ZnSO ₄ 1
6 g / l, NaSO ₄ 250 g / l, spun into a spinning bath at a temperature of 51 ° C., then the distance in the bath was 200 mm, and the stretching ratio was 16%
Then, on the roller, hot water treatment at 80 ° C and 10
Roller drying treatment at 0 ℃, 120 at 100m / min
Untwist d / 25f onto cheese. At this time, it should be noted that the aqueous dispersion of carbon particles should be used immediately after preparation, and if left for a long time, agglomeration of dispersed particles occurs,
When added to the spinning dope, dispersion unevenness is likely to occur. further,
When the dispersion is added to a spinning stock solution that may cause shock aggregation such as strong alkalinity, it is necessary to avoid the shock aggregation as much as possible by vigorous stirring at the same time as the addition.

Here, the cellulosic fiber refers to cellulosic fiber other than natural fiber, and the content of carbon particles in the fiber is 5% by weight or more and 70% by weight or less and zinc is contained in the range of 30 ppm or more and 5000 ppm or less. The point is very important. For example, taking viscose rayon as an example, the content of carbon particles is out of this range and is 5
If the content of zinc is less than 30% by weight, the specific resistance value of the fiber is almost the same as that of the yarn with no carbon particles added, even if the zinc content is in the range of 30 ppm or more and 5000 ppm or less.
On the other hand, when the content of carbon particles is higher than 70% by weight, there are many broken yarns during spinning and continuous spinning cannot be performed. Therefore, the amount of conductive carbon particles added is preferably in the range of 5 to 70% by weight, more preferably 10 to 30% by weight, based on the fibers, from the viewpoint of electrical conductivity and mechanical performance of the fibers.

Further, regarding the content of zinc, it is 30
If it is less than ppm, the variation of the specific resistance value becomes 10 ⁵ Ωcm. On the contrary, if it exceeds 5000 ppm, the spinning tone such as a broken yarn at the time of spinning can be obtained even if the content of carbon particles is within the range of the present invention. It deteriorates and there is no operability. But,
When the amounts of the contained carbon particles and zinc are both within the range of the present invention, the variation in the specific resistance value is within 10 ³ Ωcm, and a fiber having extremely stable conductive performance can be obtained.
The sharpness of the copy image obtained by the application brush having such a pile of conductive cellulose fibers becomes unprecedented and the difference becomes clear as the number of times of copying is increased. Such an electrically conductive cellulosic fiber has never been produced so far and can be produced for the first time by the present invention.

Up to now, the idea of adding a metal such as zinc to viscose as a spinning dope has been proposed in Japanese Patent Publication No. 30-514 (Dupont), Japanese Patent Publication No. 35-11854.
Manufacture of crimp staples found in Japanese Examined Patent Publication No. 35-13715 (Kanebo), and improved mechanical properties of fibers such as Japanese Examined Patent Publication No. 31-3314 (Narm Loose) and Japanese Examined Patent Publication No. 35-17914 (Kanebo). Something to try,
Although the production of hollow fibers disclosed in Japanese Examined Patent Publication No. 33-6657 (Toyobo) was known, it was obvious that none of them was intended to impart or improve the conductive performance. It is also a fiber that does not contain carbon particles.

Zinc in viscose rayon fiber is usually
It exists in the form of zinc sulfide, but the amount of zinc in the present invention is a value measured as metallic zinc as shown below, and a conductive cellulose fiber sample is put in a magnetic crucible and ashed in an electric furnace. Treated, allowed to cool and dissolved in about 35% hydrochloric acid,
IS0102.53.2-1993 Flame atomic absorption method or the like can be used for measurement.

The specific resistance value ρΩcm was measured under the condition of relative humidity of 30% using a resistance value measuring instrument SM-8210 Ultra Ultra Insulator manufactured by Toa Denpa Kogyo Co., Ltd. More specifically, the sample length L of the conductive regenerated cellulose fiber
(Cm) is 10 cm, and 100 is set between these 10 cm.
An electric resistance value R (Ω) at that time is measured by applying a voltage of (V), and ρ (Ω · c) where S (cm ² ) is the cross-sectional area of the fiber.
m) = R × (S / L) Here, S is considered to be the fiber density d = 1.5 g / cm ^3, and D is the total denier value read as it is as weight (g), and S = D /
It was calculated from (900,000 × d).

[0027]

EXAMPLES Representative examples will be shown below, but this example is an example for facilitating the understanding of the present invention, and the present invention is not limited thereto. Example 1 Viscose, which is a spinning stock solution having a cellulose concentration of 8% by weight and an alkali concentration of 6% by weight, and a conductive carbon particle dispersion liquid T-1375 Black (R) EC manufactured by Dainichiseika Seika.
(Carbon pure content 10.0% by weight) was added to adjust the carbon particle addition rate to cellulose to be 18% by weight, and the mixture obtained by high speed stirring at 3000 rpm for 30 minutes was vacuum degassed and spun. A stock solution was obtained.

The viscose thus obtained was used with a Nelson type continuous spinning machine and the hole diameter was 0.07 mm and the number of holes was 25.
H ₂ S from the spinning nozzle at 11 cc / min
O ₄ 130 g / l, ZnSO ₄ 16 g / l, NaSO ₄
After spinning in a spinning bath of 250 g / l and a temperature of 51 ° C., the distance in the bath was 200 mm, and the stretching ratio was 16%.
℃ hot water treatment and 100 ℃ roller drying treatment, 10
At a rate of 0 m / min, 120 d / 25 f was untwisted on cheese to obtain 1.75 kg of yarn. 5 from the surface of this cheese
Table 1 shows the results of evaluating the conductive performance of each sample by sampling every 000 m.

[0029]

[Table 1]

At this time, the zinc content was 830 ppm,
The specific resistance value as the conductive performance is 1.1 × 10 ^{6 to} 5.4 ×
It was within 10 ⁷ Ωcm.

With this yarn, the base cloth density (warp 35 yarns / cm × weft 40 yarns / cm) and the pile density of 25 yarns per strain were about 30,000 yarns /
After weaving as a pile of a pile tape having an inch ² , a pile length of 12 mm and a weaving width of 15 mm, it was spirally wound around a cylindrical surface having a diameter of 20 mmφ to prepare an application brush for a copying machine, and a repeating test of copying was conducted. Table 2 shows the results of comparing the sharpness of the copied images between the first copying and the 20,000th copying. Even in the copied image after 20,000 times, only slight streaks were generated, which was a good result.

[0032]

[Table 2]

Example 2 The same dispersion of conductive carbon particles as in Example 1 was added to viscose having a cellulose concentration of 8% by weight and an alkali concentration of 6% by weight, and the concentration of cellulose was 16.5% by weight immediately before spinning. After injection, the rotation speed continues to be 3000r.
The mixture was stirred and uniformly dispersed with a line mixer of pm.

The viscose thus directly adjusted on-line in this way was made to have a hole diameter of 0.08 mm by using a Nelson type continuous spinning machine.
H ₂ SO ₄ 130 g / l, ZnSO ₄ 16 g / l under the discharge condition of 12 cc / min from a spinning nozzle with 50 holes.
1, NaSO ₄ 250 g / l, spun into a spinning bath at a temperature of 60 ° C., and then, the hollow length of the bath was 200 mm, the stretching ratio was 12%, and the mixture was washed with warm water at 40 ° C. and dried at 300 m at 42 m / min.
The cheese of d / 50f was wound up.

From the surface of this cheese, sampling was performed for each yarn layer in the same manner as in Example 1, and the results of evaluating the respective conductive properties are shown in Table 1. Zinc content is 1690 pp
m, the specific resistance value as the conductive performance is 2.3 × 10 ^{5 to} 6.
It was within the range of 5 × 10 ⁶ Ωcm.

This yarn is used as a base fabric density (warp 35 yarns / cm × weft 40 yarns / cm) and a pile density of 25 yarns per strain is about 30,000 yarns /
After weaving as a pile of a pile tape having an inch ² , a pile length of 12 mm and a weaving width of 15 mm, the pile was attached to a support to prepare an application brush for a copying machine, and repeated tests of copying were conducted. Table 2 shows the results of comparing the sharpness of the copied images between the first copying and the 20,000th copying. Even in the copied image after 20,000 times, only slight streaks were generated, which was a good result.

Example 3 The addition ratio of conductive carbon particles to cellulose was 15
The evaluation results were the same as in Example 1 except that the content was% by weight. The zinc content was 679 ppm, and the specific resistance value was 7.5 × 1.
It was within the range of 0 ^{6 to} 2.1 × 10 ⁸ Ωcm.

Example 4 The addition ratio of conductive carbon particles to cellulose was 15
The evaluation results when all were the same as in Example 2 except that the weight percentage was set to zinc content of 1370 ppm and specific resistance of 6.9 ×
It was within the range of 10 ^{6 to} 9.8 × 10 ⁷ Ωcm.

Example 5 The addition ratio of conductive carbon particles to cellulose was set to 50.
The evaluation results were the same as in Example 2 except that the content was 1% by weight, the zinc content was 1805 ppm, and the specific resistance value was 1.0 ×.
Although it was within the range of 10 ^{2 to} 8.8 × 10 ² Ωcm, the dry strength was slightly lowered to 1.02 g / d.

Example 6 Using the same viscose as in Example 1, using a Nelson type continuous spinning machine, H ₂ SO ₄ 130 g / min was discharged from a spinning nozzle having 0.07 mm and 25 holes and 11 cc / min.
1, ZnSO ₄ 16 g / l, NaSO ₄ 250 g / l,
After spinning in a spinning bath at a temperature of 51 ° C, the distance in the bath is 200 m
m, stretching ratio 16%, followed by 15 g / l hydrochloric acid treatment and 100 ° C. roller drying treatment, and 120 d / 25 f was untwisted at 100 m / min onto cheese to be 1.75.
I got a yarn of kg. The results obtained by sampling the surface of this cheese for each yarn layer in the same manner as in Example 1 and evaluating the conductive performance of each are shown in Table-1.

The zinc content at this time was 107 ppm,
The specific resistance value as the conductive performance is 2.4 × 10 ^{5 to} 6.7 ×
It was within 10 ⁶ Ωcm.

This yarn is used as a base cloth density (warp 35 yarns / cm × weft 40 yarns / cm) and a pile density of 25 yarns per strain is about 30,000 yarns /
After being woven as a pile of a pile tape having an inch ² , a pile length of 12 mm and a weave width of 15 mm, it was spirally wound around a cylindrical surface having a diameter of 20 mmφ to prepare an application brush for a copying machine, and repeated tests of copying were conducted. Table 2 shows the results of comparing the sharpness of the copied images between the first copying and the 20,000th copying. Even in the copied image after 20,000 times, only slight streaks were generated, which was a good result.

Example 7 Viscose, which is a spinning stock solution having a cellulose concentration of 8% by weight and an alkali concentration of 6% by weight, is a conductive carbon particle dispersion liquid T-1375 Black (R) EC manufactured by Dainichiseika Seika.
(Carbon pure content 10.0% by weight) was added to make the ratio of carbon particles added to cellulose 18% by weight, and 0.1% by weight zinc sulfate was added to viscose, followed by high speed stirring at 3000 rpm for 30 minutes. Then, the mixture was degassed in vacuum to obtain a spinning dope.

The viscose thus obtained was wound under the same conditions as in Example 6 except for viscose, and wound on cheese to obtain 1.75 kg of yarn. The results obtained by sampling the surface of this cheese for each yarn layer in the same manner as in Example 1 and evaluating the conductive performance of each are shown in Table-1.

The zinc content at this time was 4631 ppm.
Then, the specific resistance value as the conductive performance is 1.9 × 10 ^{5 to} 5.
It was within 5 × 10 ⁶ Ωcm.

This yarn is used as a base cloth density (warp 35 yarns / cm × weft 40 yarns / cm) and a pile density of 25 yarns per strain is about 30,000 yarns /
After being woven as a pile of a pile tape having an inch ² , a pile length of 12 mm and a weave width of 15 mm, it was spirally wound around a cylindrical surface having a diameter of 20 mmφ to prepare an application brush for a copying machine, and repeated tests of copying were conducted. Table 2 shows the results of comparing the sharpness of the copied images between the first copying and the 20,000th copying. Even in the copied image after 20,000 times, only slight streaks were generated, which was a good result.

Example 8 Evaluation results were the same as in Example 6 except that the hydrochloric acid concentration in the hydrochloric acid treatment was 35 g / l, and the zinc content was 36 pp.
m, specific resistance value is 1.7 × 10 ^{5 to} 9.6 × 10 ⁶ Ωcm
Within the range.

Comparative Example 1 Using the same viscose as in Example 1, H ₂ SO ₄ 130 g / l and ZnSO ₄ 16 g / l were discharged from a spinning nozzle with 0.07 mm and 25 holes and 11 cc / min. ,
NaSO ₄ 250 g / l, RB1 was spun in a spinning bath at a temperature of 51 ° C., and RB1 was spun at a spinning speed of 100 m / min by a centrifugal spinning method.
20d / 25f was wound into a pot rotating at 7200 rpm. At this time, the amount of yarn wound up was 625 g, and the twist was about 70 T / M. Sequential scouring treatment in the cake state, that is, normal temperature water washing for 40 minutes, desulfurization Na ₂ S 3
g / l, 50 ° C, 42 minutes, Bleached NaOCl 0.35g
/ L, 25 ° C, 56 minutes, Euling Miyoshi oil / fat sohumin L 2 g / l, 40 ° C, 28 minutes, and dried at 80 ° C for 60 hours to obtain 625 g of cake.

The cake yarn was evaluated in the same manner as in Example 1. As a result, the specific resistance value was 2.5 × 10 ^{5 to} 4.2.
There was a large variation in the range of 10 ⁹ Ωcm. At this time, the zinc content in the fiber was 23 ppm.

Further, an application brush for a copying machine was processed in the same manner as in Example 1 and a repeated copying test was conducted. Table 1 shows the results of comparing the sharpness of the copied images at the 1st copying and the 20,000th copying. A few light-colored streaks were generated at the 1st copying, and dark streaks were generated on the entire surface at 20,000th copying. .

Comparative Example 2 Evaluation results were the same as in Example 2 except that the addition ratio of the conductive carbon particles to cellulose was set to 2% by weight. The specific resistance value was 2.8 × 10 ^{8 to} 7.7. × a 10 ¹⁰ [Omega] cm by variation did not reach to said smaller ones usually it conductive rayon rather little difference rayon. The zinc content at this time was 1323 ppm.

Comparative Example 3 Spinning was performed in the same manner as in Example 6 except that zinc sulfate was added to the viscose in an amount of 1% by weight. Incidentally, the zinc content was 6357 ppm.

Comparative Example 4 The addition ratio of conductive carbon particles to cellulose was set to 76.
The same procedure as in Example 2 was carried out except that the content was changed to wt%. However, there were many broken yarns and continuous spinning was not possible.

 ─────────────────────────────────────────────────── ─── Continued Front Page (72) Inventor Yoshitaka Harada 7471 Tamashima Otoshima, Kurashiki City, Okayama Prefecture Kuraray Co., Ltd.

Claims (1)

[Claims] 1. Carbon particles in a fiber are 5% by weight or more 7
Contains 0% by weight or less and contains zinc in an amount of 30 ppm or more and 500
A conductive cellulosic fiber containing 0 ppm or less.