JP2003306832A - Polyamide multifilament yarn and brush comprising the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide uniform and high-density charging and a cleaner when a charging brush or a cleaner brush is used, and to achieve high image quality in electrophotographic recording type dry copiers, facsimiles, printers, etc., by stably producing a polyamide multifilament yarn comprising electroconductive carbon without forming slubs. <P>SOLUTION: The polyamide multifilament yarn comprises the electroconductive carbon and contains magnesium in an amount of 8-25 mmol in 1 kg of the polyamide multifilament yarn. The Uster unevenness of the polyamide multifilament yarn is ≤1.5% and 10-40 wt.% of the electroconductive carbon is contained in the polyamide multifilament yarn. Furthermore, the polyamide multifilament yarn has 0.5-4 dtex single filament fineness and 10<SP>3</SP>to 10<SP>8</SP>Ωcm specific resistivity value. The charging brush and cleaner brush are obtained by using the polyamide multifilament yarn. <P>COPYRIGHT: (C)2004,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a conductive polyamide multifilament for use in electrophotographic recording type dry copying machines, facsimiles, printers, etc., and particularly to nodes having uneven fineness in the longitudinal direction. This is because the image quality is improved by not creating it. Further, the present invention relates to a charging brush and a cleaner brush using the polyamide multifilament for an electrophotographic recording type dry copying machine, a facsimile, a printer and the like.

[0002]

2. Description of the Related Art Cellulosic fibers and vinylon conductive threads are used as multifilaments containing conductive carbon fine particles used in electrophotographic recording type dry copying machines, facsimiles, printers and the like.

In order to reduce the influence of humidity change, the cellulosic fiber is subjected to flame retardant treatment as described in, for example, Patent Document 1, and low humidity (temperature 20 ° C., humidity 15%).
RH) and the ratio of variation in specific resistance at high humidity (temperature 20 ° C, humidity 65% RH) 10 ³ Ωcm
However, in order to further reduce variations in image quality due to changes in temperature and humidity during copying, it is desired to reduce the ratio of specific resistance of the conductive yarn to low humidity and high humidity.

Further, since the cellulosic fiber exhibits a stable electric resistance value even when it is used for a long time in an environment where the temperature and humidity change greatly, for example, it is subjected to hot water swelling treatment as described in Patent Document 2, The standard deviation of the electric resistance variation in the yarn length direction is 0.3 or less, but the cellulose-based fiber is
Due to the wet spinning, partial fineness unevenness is likely to occur, and charging unevenness is generated on the photoconductor during printing, so that it is difficult to obtain image quality of image quality.

In the vinylon conductive yarn, for example, as described in Patent Document 3, the single yarn fineness is about 4 to 5 decitex, and the pile density of the conductive yarn when woven is about 30,000 yarns / inch ² In order to further improve the image quality, it is desired to increase the pile density when weaving. Further, since the vinylon conductive yarn is wet-spun, partial fineness unevenness is likely to occur, and charging unevenness is generated on the photosensitive member during printing, so that it is difficult to obtain an image quality of image quality.

Further, as a method of increasing the pile density, it is preferable to reduce the fineness of a single yarn, and a method of reducing the fineness by melt spinning is known. Polyester and polyamide are known for melt spinning, but when polyester is used as a conductive brush, the bending stress of the polyester is high, and therefore, there is a problem that the photoconductor that comes into contact with the brush is damaged when used for a long period of time.

On the other hand, for polyamide, as described in Non-Patent Document 1, a method using a conductive thread in which conductive carbon powder is dispersed in a polyamide resin fiber is known.

The conductive carbon powder obtains conductivity by the structure as described in Non-Patent Document 2, but since the bond strength of the secondary structure is particularly weak, the structure is destroyed during melting and the specific resistance is increased. However, when the conductive brush is not stable, the image quality is deteriorated. Further, in melt spinning, the destroyed structure is deposited around the spinneret hole, and especially in the case of polyamide, bleeding out around the spinneret hole together with the monomers and oligomers generated during melting forms foreign matter around the spinneret hole, resulting in yarn breakage. There have been many problems. Also, due to the foreign matter due to the conductive carbon bleeding out together with the monomers and oligomers attached around the spinneret holes, the single yarns drip during spinning, resulting in knots, and when using a charging brush or a cleaner brush, the electrons are knotted into the knots. Since the image is concentrated, there is a problem that the image quality is deteriorated. For this reason,
For example, as described in Patent Document 4, a method of limiting the amount of amino terminal groups or carboxyl terminal groups of polyamide to an extremely low level and controlling the content of low molecular weight components for the purpose of reducing the contamination of the die of a molding apparatus is proposed. Although proposed, this method requires the addition of a large amount of end-capping agent such as monoamine and monocarboxylic acid.In this case, it takes a long time for polymerization to obtain a polyamide having a degree of polymerization required for molding. Or special polymerization such as reduced pressure polymerization is required, and there is a possibility of quality deterioration due to thermal decomposition reaction, and in industrial scale production, a drastic solution is required from an economical point of view.

Further, in order to reduce the amount of cyclic monomer produced during melt spinning, film formation, or molding, for example, as described in Patent Document 5, polyamide and an alkaline earth metal compound, particularly magnesium hydroxide and oxidation. A polyamide composition comprising a mixed crystal of magnesium and 0.01 Torr or less and having a cyclic monomer amount at the time of melting at 250 ° C. of not more than a prescribed amount (Japanese Patent Laid-Open No. Hei 1
No. 0-259306) has been proposed, but there is no description about the amount of a low polymerized product including an oligomer in a monomer at a normal working pressure, and in particular, in regard to a polyamide containing a conductive carbon, it relates to solving the above problem. There is no description. In addition, there is a problem that the blending amount of mixed crystals of magnesium hydroxide and magnesium oxide is large and the filtration pressure during spinning increases.

[0010]

[Patent Document 1] Japanese Patent Laid-Open No. 2000-160427 (paragraph [0055])

[Patent Document 2] Japanese Patent Laid-Open No. 2000-355823 (paragraphs [0029] to [0032])

[Patent Document 3] Japanese Patent Laid-Open No. 2001-303363 (paragraph [0021])

[Patent Document 4] JP-A-8-231711 ([00
05] paragraph)

[Patent Document 5] Japanese Patent Laid-Open No. 10-259306 ([0
007] paragraph)

[Non-Patent Document 1] "Continued basics of electrophotographic technology": Corona Co., Ltd. 1996 (257 pages, 18 to 22 paragraphs)

[Non-Patent Document 2] "Development and Application of Conductive Filler": Technical Information Institute Co., Ltd. 1994 (78 pages, paragraphs 16-18)

[0011]

Therefore, in the present invention, a polyamide multifilament containing conductive carbon can be stably produced without forming a knot so that a uniform and high density can be obtained when a charging brush or a cleaner brush is used. It is an object of the present invention to enable charging and cleaning, and to achieve high image quality in electrophotographic recording type dry copying machines, facsimiles, printers and the like.

[0012]

In order to solve the above problems, the polyamide multifilament of the present invention mainly has the following constitution. That is, (1) a polyamide multifilament containing conductive carbon, containing 8 to 25 mmol of magnesium per 1 kg of the polyamide multifilament, and having a specific resistance value of 10 ³ to 10 ⁸ Ωcm. A polyamide multifilament characterized in that it is characterized.

(2) A polyamide multifilament containing conductive carbon, having a Worcester spot of 1.5%.
The polyamide multifilament according to claim 1, wherein:

(3) A polyamide multifilament containing conductive carbon, characterized in that the content of the conductive carbon is 10 to 40% by weight.
The polyamide multifilament according to claim 1 or 2.

(4) A polyamide multifilament containing conductive carbon, having a single yarn fineness of 0.5 to
It is 4 decitex, The polyamide multifilament in any one of Claims 1-3 characterized by the above-mentioned.

(5) A brush for an electrophotographic recording type dry copying machine, comprising the polyamide multifilament according to any one of claims 1 to 4.

[0017]

BEST MODE FOR CARRYING OUT THE INVENTION The polyamide constituting the present invention is
A so-called hydrocarbon group is a high molecular weight compound linked to the main chain through an amide bond, and particularly nylon 6 and nylon 6
6 is preferred.

The conductive carbon used here is not particularly limited as long as it is a conductive powder such as acetylene black. However, if the particles are large, the increase in filtration pressure during spinning and the yarn during spinning are suppressed. Taking into consideration the breakage and the improvement of the strength of the fiber, it is preferable to use those having a thickness of 20 μm or less. Also, like conductive carbon particle-dispersed nylon pellets “CARBOREX NYRON YT-01” manufactured by Dainippon Ink and Chemicals,
The conductive carbon particles in the dispersion-blended nylon pellets may already be used by the pigment manufacturer.

As the method of incorporating the conductive carbon in the polyamide multifilament, a method of blending and melting the conductive carbon with the polyamide pellet, and a method of blending and melting the polyamide pellet with a master pellet containing a high concentration of the conductive carbon Examples thereof include a method, a method in which conductive carbon is added to a molten polyamide and kneading, and a method in which a molten polyamide containing a high concentration of conductive carbon is kneaded.

The polyamide multifilament of the present invention contains 8 to 8 kg of polyamide multifilament.
It is necessary to contain 25 mmol magnesium. This magnesium exists in a cation state or as a salt. When the amount of magnesium is less than 8 millimoles per 1 kg of the polyamide composition, for example, the regeneration of the monomer or oligomer during the production of the fiber by melting cannot be sufficiently suppressed, and the conductivity bleeding out from these monomers, oligomers and polyamides is increased. Carbon becomes dirty around the forming die hole, causing many knots and yarn breakage, resulting in poor operability. Further, even if the amount is more than 25 millimoles, the effect is comparable and not preferable from the economical point of view, and particularly when conductive carbon is contained, magnesium remaining as insoluble foreign matter in the polyamide is not compatible with the conductive carbon. Together, they cause problems such as an increase in filtration pressure with a filter installed to remove foreign matter and deterioration of physical properties of molded articles.

As a method of incorporating a magnesium component in the polyamide multifilament, a method of blending and melting a magnesium compound with polyamide pellets, a method of blending and melting master pellets containing a high concentration of magnesium with polyamide pellets, and a molten state Examples thereof include a method of adding a magnesium compound to the polyamide and kneading, and a method of adding a magnesium compound to a raw material or a reaction system before or during polymerization of the polyamide. Any method may be used as long as both are uniformly mixed.

As the magnesium compound, magnesium oxide, magnesium hydroxide, magnesium carbonate, etc.,
And mixtures thereof, but it is preferable to use magnesium oxide or magnesium hydroxide.

The content of conductive carbon in the polyamide multifilament of the present invention is 10 to 40% by weight, preferably 15 to 35%. Conductive carbon content is 1
If it is less than 0%, the specific resistance value of the polyamide multifilament decreases, and there arises a problem that printing cannot be performed when printing. In addition, the content of conductive carbon is 40%
If it exceeds, the strength of the polyamide multifilament is lowered and the operability becomes poor.

The polyamide composition of the present invention may contain various additives as long as the effects of the present invention are not impaired. Examples of this additive include a stabilizer such as a manganese compound, a plasticizer, a lubricant, a flame retardant, a conductivity-imparting agent, and a fibrous reinforcing agent.

The Worm spot of the polyamide multifilament of the present invention is preferably 1.5% or less. If the Wooster spot exceeds 1.5%, the electrical resistance of the thick and thin parts of the fineness will differ when using a brush,
There arises a problem that charge unevenness is generated during charging of the photosensitive material, resulting in deterioration of image quality.

The single yarn fineness of the polyamide multifilament of the present invention is preferably 0.5 to 8 decitex, more preferably 0.5 to 4 decitex. If the single yarn fineness is less than 0.5 decitex, the yarn breakage during spinning is large and the spinnability deteriorates. When the single yarn fineness exceeds 8 decitex, the pile density of the conductive yarns when weaving becomes small, and the image quality when copying becomes low. Further, in a copying machine for full color and high image quality, it is necessary to apply a high-density charge to the photoconductor, and it is effective to reduce the single yarn fineness in order to increase the pile density of the conductive brush. From such a viewpoint, it is more preferable that the single yarn fineness is 4 decitex or less.

The specific resistance value of the polyamide conductive yarn of the present invention is
(Temperature 20 ° C, Humidity 30% RH) 10 ³-10⁸In Ωcm
Preferably 10³-10⁷Ωcm is more preferable.
Specific resistance is 10³If it is less than Ωcm, use a conductive brush to increase the voltage.
When hung, the electrons move to the adjacent conductive thread and printing is possible.
There is a problem that there is no. Specific resistance is 10⁸Over Ωcm
Then, even if a voltage is applied, electrons cannot move in the fiber and
This is because the problem that it cannot be copied occurs.

The electrophotographic recording type brush for a dry copying machine is an application brush for contact-charging a photoconductor in place of non-contact corona discharge, or a cleaning brush for removing charges and toner remaining on the photoconductor. In either case, a pile fabric made of electrically conductive fibers may be wound around a cylindrical metal rod around a bias, or the pile fabric may be simply attached to a plate to form a brush.

[0029]

The present invention will be described in more detail with reference to the following examples. The evaluation method is as follows.

A. Specific resistance value With a super insulation resistance tester (TERAOHMMETER R-503 manufactured by Kawaguchi Denki Co., Ltd.), a voltage of 100 (V) is applied for a test length of 10 cm, and an electric resistance value under the conditions of a temperature of 20 ° C. and a humidity of 30% RH ( Ω /
cm) was measured and calculated from the following formula (1). RS = R × D / (10 × L × SG) × 10 ⁻⁵ (1) RS: Specific resistance (Ωcm) R: Electric resistance value (Ω) D: Thread weight per 10,000 m L: Test length (cm) SG : Yarn density (g / cm ³ ) B. Wurster spots A Wurster fineness spot measuring device (UT3 type manufactured by Zellbeger Worster Co., Ltd.) was used to measure a yarn length of 150 m at a speed of 50 m / min, and the obtained fineness spots were integrated and calculated by half-inert.

C. Number of Knots Polyamide multi-filament yarn was knitted for about 5000 m by a knitting machine (200N) with one-thread feeding, and the number of knots in the knitted fabric was visually inspected and evaluated according to the following criteria. ◯: 0 pieces △: 1-3 pieces ×: 4 pieces or more D.I. Spinning yarn breakage Melts at 270 ° C, discharges about 40 g from a round hole spinneret with 1 yarn per spinneret, cooling, lubrication, speed 800 m /
Winding was performed at min. The number of yarn breakages when this was spun for 1 t was evaluated according to the following criteria. ◯: 3 times / t Δ: 4 to less than 8 times / t ×: 8 times / t or more

E. Increase in filter filtration pressure during spinning The filtration pressure P of the spinning filter was calculated from the following equation (2) and evaluated according to the following criteria. ◯: 0 to less than 10 MPa Δ: 10 or more to less than 20 MPa x: 20 MPa or more P = P0-P1 (2) P0: Filtering pressure (MPa) at the start of spinning P1: Filtering pressure (MPa) 24 hours after the start of spinning .

F. Image Quality A test chart issued by the Institute of Electrophotography was copied, the image quality was determined by the sensory evaluation value (satisfaction level), and evaluated according to the following criteria. ⊚: Satisfaction level 75 or more O: Satisfaction level 50 or more and less than 75 Δ: Satisfaction level 25 or more and less than 50 x: Satisfaction level 0 or more and less than 25

Example 1 Nylon-based resin master pellets (manufactured by Dainippon Ink and Chemicals, Inc., trade name "CARBOREX NYRON YT-01") containing 35% conductive carbon were blended with nylon 6 pellets, and the carbon concentration was 25%. Then, magnesium oxide powder was blended at a ratio of 10 mmol (0.4 g) to 1 kg of the polyamide composition. This was melt-spun at a winding speed of 800 m / min and further drawn at a draw ratio of 2.2.
The filament was drawn at a doubling rate to obtain a conductive multifilament yarn having a filament fineness of 170 decitex and a 98 filament single yarn fineness of 1.7 decitex. At this time, the broken yarn was 1.
The number was 5 times / t and was good. The number of knots generated was 0 and was good. The increase in filter filtration pressure during spinning was 1 MPa, which was ◯. The specific resistance value of the obtained conductive carbon-containing polyamide multifilament was 10 ⁵ Ωcm, and the Worcester spot was 0.8%. The image quality was ◎.

Example 2 Master pellets of nylon-based resin containing 35% of molten conductive carbon (trade name "CARBOREX NYRON YT-01" manufactured by Dainippon Ink and Chemicals, Inc.) were melt-blended with molten nylon 6 pellets. , Carbon concentration 20
%, And magnesium oxide powder was blended at a ratio of 10 mmol (0.4 g) to 1 kg of the polyamide composition. This is wound and stretched by the above method to obtain a yarn fineness of 17
A conductive multifilament yarn having a single filament fineness of 2.5 decitex and 0 decitex and 68 filaments was obtained.
At this time, the number of breaks in the spun yarn was 2.0 times / t, which was ◯.
The number of knots generated was 0 and was good. The increase in filter filtration pressure during spinning was 1.5 MPa, which was ◯. The specific resistance value of the obtained conductive carbon-containing polyamide multifilament was 10 ⁴ Ωcm, and the Worcester spot was 0.7%. The image quality was ◎.

Example 3 Polyamide pellets were blended with conductive carbon and melted to a carbon concentration of 25%, and 10 millimoles (0.4 mmol) of magnesium oxide powder was added to 1 kg of polyamide composition.
Blended in proportion g). This was wound and stretched by the above-mentioned method to obtain a conductive multifilament yarn having a yarn fineness of 170 decitex and a 48 filament single yarn fineness of 3.5 decitex. The yarn breakage at this time is 1.0
The number of times / t was ◯. The number of knots generated was 0 and was good. The increase in filter filtration pressure during spinning was 1 MPa, which was ◯. The specific resistance value of the obtained conductive carbon-containing polyamide multifilament was 10 ⁶ Ωcm, and the Worcester spot was 0.
It was 6%. The image quality was ◎.

Example 4 Polyamide pellets were blended with electrically conductive carbon and melted to a carbon concentration of 25%, and 10 millimoles (0.4 mmol) of magnesium oxide powder was added to 1 kg of the polyamide composition.
Blended in proportion g). This was wound and stretched by the above method to obtain a conductive multifilament yarn having a yarn fineness of 170 decitex and a 24 filament single yarn fineness of 7 decitex. At this time, the spinning yarn breakage is 1.5 times /
It was t and was o. The number of knots generated was 0 and was good. The increase in filter filtration pressure during spinning was 1 MPa, which was ◯. The specific resistance value of the obtained conductive carbon-containing polyamide multifilament was 10 ⁶ Ωcm, and the Worcester spot was 0.8.
%Met. The image quality was good.

Comparative Example 1 Magnesium oxide powder was blended at a ratio of 5 mmol (0.2 g) to 1 kg of a polyamide composition having a carbon concentration of 25% by the above method. This was wound and stretched by the above method to obtain a conductive multifilament yarn having a single fineness of 1.7 decitex. At this time, the number of yarn breakage of the spun yarn was 9.2 times / t, which was bad, and the number of knots was 8, which was x. The image quality was poor.

Comparative Example 2 Magnesium oxide powder was blended at a rate of 30 mmol (1.2 g) to 1 kg of a polyamide composition having a carbon concentration of 25% by the above method. This was wound and stretched by the above method to obtain a conductive multifilament yarn having a single fineness of 1.7 decitex. At this time, the number of breaks in the spun yarn was 1.4 times / t, which was ◯. However, the increase in filter filtration pressure during spinning was 25 MPa, which was x, and spinning was impossible.

Comparative Example 3 Nylon-based resin master pellets (manufactured by Dainippon Ink and Chemicals, Inc., trade name "CARBOREX NYRON YT-01") containing 35% conductive carbon were blended with nylon 6 to a carbon concentration of 5%. , 10 millimoles of magnesium oxide powder (0.4 g) per 1 kg of polyamide composition
Blended in the proportion of. This was spun and stretched by the above method to obtain a conductive multifilament yarn having a single fineness of 1.7 decitex. At this time, the number of breaks in the spun yarn was 1 / t, which was ◯, and the number of knots generated was 0, which was ◯. The increase in filter filtration pressure during spinning was 1 MPa, which was ◯. However, the specific resistance value of the obtained conductive carbon-containing polyamide multifilament was 10 ¹² Ωcm, and printing was impossible.

Comparative Example 4 Polyamide pellets were blended with conductive carbon and melted to a carbon concentration of 45%, and 10 mmol (0.4) of magnesium oxide powder was added to 1 kg of polyamide composition.
Blended in proportion g). This was spun and stretched by the above method to obtain a conductive multifilament yarn having a single fineness of 1.7 decitex. The spinning yarn breakage at this time is 15 times / t
And was x. The specific resistance value of the obtained conductive carbon-containing polyamide multifilament is 10 ¹ Ωcm.
It was impossible to print.

Comparative Example 5 By the method of Example 1 described in Patent Document 3, a vinylon conductive yarn conductive yarn having 1100 decitex and a single yarn fineness of 4.4 decitex was obtained. The obtained vinylon conductive yarn has 2 Worcester spots.
%, And the image quality was Δ.

[0043]

[Table 1]

[0044]

EFFECT OF THE INVENTION In the conductive carbon-containing polyamide multifilament of the present invention, by containing magnesium, stains around the spinneret holes in the melt spinning are suppressed, so that there is no particular knot part which is uneven in fineness in the length direction. ,
Single yarn fineness can be made thin, and by obtaining a specific resistivity value, when used as a conductive brush used in electrophotographic recording type dry copying machines, facsimiles, printers, etc.,
Printing accuracy can be improved.

Continued front page    F-term (reference) 2H134 GA01 GB02 HB01 HB02 HB03                       KE01 KG01 KH01 KH10                 2H171 FA07 FA11 FA17 FA26 FA30                       GA01 GA15 PA08 QB04 QB07                       QC23 QC25 TB14 UA03 UA04                       UA10 UA22 XA05                 2H200 FA13 FA18 FA19 GB13 HA03                       HB07 HB45 HB46 HB47 LC09                       MA04 MA06 MA17 MA20 MB01                       MB05 MC11                 4L035 BB31 EE13 FF01 JJ03 JJ04                       JJ10 LC02                 5G301 DA18 DA51 DD10

Claims (5)

[Claims] 1. A polyamide multifilament containing conductive carbon, which contains 8 to 25 mmol of magnesium per 1 kg of the polyamide multifilament and has a specific resistance value of 10 ³ to 10 ⁸ Ωcm. A polyamide multifilament characterized in that it is characterized. 2. The polyamide multifilament containing conductive carbon, wherein the Worcester spot is 1.5% or less, and the polyamide multifilament according to claim 1. 3. A polyamide multifilament containing conductive carbon, wherein the content of the conductive carbon is 10 to 40% by weight. . 4. The polyamide multifilament according to claim 1, wherein the polyamide multifilament contains conductive carbon and has a single yarn fineness of 0.5 to 4 decitex. 5. A brush for an electrophotographic recording type dry copying machine, comprising the polyamide multifilament according to any one of claims 1 to 4.