JP2007321274A - Electroconductive polyester fiber and electroconductive brush using the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a polyester fiber for electroconductive brushes excellent in durability, having little dispersion in electric resistance and able to be suitably used for image forming apparatuses, especially such as laser printers and the like. <P>SOLUTION: The electroconductive polyester fiber containing two species of specific compounds and having 1.0x10<SP>8</SP>-1.0x10<SP>11</SP>Ω/cm cross-sectional resistance under 40% relative humidity is excellent in durability and has little deviation in values of electric resistance. Therefore, high quality images are provided by using a pile yarn of the same as the electroconductive brushes for the image forming apparatuses. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a novel polyester fiber having conductivity suitable for a brush used in an image forming apparatus such as a laser printer and a conductive brush using the same.

  As fibers for brushes used in electrophotographic recording type dry copying machines, facsimiles, printers, etc., as described in the following Patent Documents 1 to 4, vinylon conductive yarns containing cellulose fibers or conductive carbon, Nylon conductive yarn or polyester conductive yarn is used.

  However, cellulosic fibers, vinylon fibers, and nylon fibers have poor mechanical strength, particularly durability, and are formed when used as conductive brushes such as static elimination brushes, charging brushes, or cleaning brushes in image forming apparatuses such as laser printers. There is a problem that the quality of the image is deteriorated.

  On the other hand, in the polyester conductive yarn and nylon conductive yarn kneaded with conductive carbon, it is difficult to uniformly disperse the carbon particles in the fiber in the raw yarn manufacturing stage, and the variation in the electric resistance value of the conductive yarn is large. When used as a conductive brush for the image forming apparatus, there is a problem that the formed image varies from product to product.

JP-A-9-491117 JP 2000-355823 A JP 2000-160427 A JP 2003-66669 A

  The main object of the present invention has been made in view of the above-described prior art, and is excellent in durability and has little variation in electric resistance value, and particularly for conductive brushes that can be suitably used for image forming apparatuses such as laser printers. It is to provide a novel polyester fiber. Another object of the present invention is to provide a conductive brush using the polyester fiber.

As a result of intensive studies to solve the above problems, the present inventor has a yarn cross-sectional resistance value of 1.0 × 10 ^{8 to} 1.0 × 10 ¹¹ Ω / cm at a humidity of 40% containing a specific compound. It has been found that when a polyester fiber having a certain conductivity is used, it has excellent durability and there is little variation in electrical resistance value, and when this is used as a conductive brush of an image forming apparatus, a high-quality image can be obtained. The present invention has been completed.

かつ下記式（II）で表される有機金属スルホン酸塩を繊維重量基準で４〜１０％含有する、

ことを特徴とする、湿度４０％での糸断面抵抗値が１．０×１０^８〜１．０×１０^１１Ω／ｃｍである新規な導電性ポリエステル繊維が提供される。 That is, according to the present invention, a filament yarn made of an aromatic polyester having a yarn cross-sectional resistance value of 1.0 × 10 ^{8 to} 1.0 × 10 ¹¹ Ω / cm at a humidity of 40%. There is provided a novel conductive polyester fiber characterized by having In a preferred embodiment of the present invention, the polyoxyethylene-based polyether having a weight average molecular weight of 5000 to 16000 represented by the following formula (I) is contained in an amount of 2.0 to 3.0% based on the fiber weight.

And the organometallic sulfonate represented by the following formula (II) is contained 4 to 10% based on the fiber weight,

A novel conductive polyester fiber having a yarn cross-section resistance value at a humidity of 40% of 1.0 × 10 ^{8 to} 1.0 × 10 ¹¹ Ω / cm is provided.

  Moreover, according to this invention, the electroconductive brush characterized by using the above-mentioned electroconductive polyester fiber for a pile yarn is also provided.

  The polyester fiber of the present invention is excellent in yarn-making property and durability, has little variation in electrical resistance value between fibers, and is extremely useful as a material for a brush suitably used for an image forming apparatus such as a laser printer. A brush made of a pile fabric using fibers as pile yarns has excellent uniform charging, charge removal, and cleaning effects, and can be suitably used as a brush for an image forming apparatus such as a laser printer.

Hereinafter, embodiments of the present invention will be described in detail.
The aromatic polyester referred to in the present invention is an aromatic polyester having an aromatic ring as a main repeating unit of a polymer. Preferred examples of the aromatic polyester include polyethylene terephthalate, polypropylene terephthalate, and polybutylene terephthalate. Further, it may be a polyester obtained by copolymerizing a small amount using another acid component and / or glycol component as part of the acid component and / or glycol component. In the present invention, among them, polyethylene terephthalate, polypropylene terephthalate and copolymers thereof can be preferably used because they have mechanical properties suitable for woven and knitted fabric applications.

These aromatic polyesters preferably have an intrinsic viscosity (measured in an O-chlorophenol solution at 35 ° C.) of 0.50 to 0.65.
The aromatic polyester has a small amount of additives such as a lubricant, a pigment, a dye, an antioxidant, a solid phase polymerization accelerator, and a fluorescent whitening agent as necessary, as long as the effects of the present invention are not impaired. , Antistatic agents, antibacterial agents, ultraviolet absorbers, light stabilizers, heat stabilizers, shading agents, matting agents and the like may be included.

The polyester fiber of the present invention is required to have electrical conductivity having a yarn cross-sectional resistance value of 1.0 × 10 ^{8 to} 1.0 × 10 ¹¹ Ω / cm at a relative humidity of 40%, at a temperature of 25 ° C., relative The yarn cross-sectional resistance value at a humidity of 40% is preferably 1.0 × 10 ^{8 to} 1.0 × 10 ¹⁰ Ω / cm. In general, the conductive performance of the yarn is easily affected by the surrounding humidity environment including the composite spun polyester fiber using conductive carbon. For this reason, in order to evaluate the conductive performance of the yarn itself, it is important to evaluate in a low humidity environment to some extent. In the present invention, the yarn cross-sectional resistance is measured with the relative humidity fixed at 40%. . If the conductive performance at this time exceeds 1.0 × 10 ¹¹ Ω / cm in terms of the cross-sectional resistance value of the yarn, there is no significant difference from the antistatic region of the so-called clothing fiber, and although there is an antistatic effect due to friction, OA equipment It is not sufficient to obtain the charge eliminating effect required by the above. On the other hand, if it is less than 1.0 × 10 ⁸ Ω / cm, there is a case where a spark is generated at the time of static elimination under high voltage, and there is a risk of fire.

かつ、下記式（II）で表される有機金属スルホン酸塩を繊維重量基準で４〜１０％含有することが好ましい。

The polyester fiber of the present invention contains 2.0 to 3.0% of polyoxyethylene-based polyether represented by the following formula (I) based on the fiber weight,

And it is preferable to contain 4-10% of organometallic sulfonate represented by following formula (II) on the basis of fiber weight.

  As is apparent from the above formula (I), the polyoxyethylene-based polyether has a chain having a branched portion represented by -CjH2j + 1 and -Cj'H2j '+ 1 (hereinafter referred to as A chain block and A', respectively). It is a non-random copolymerized polyoxyethylene polyether composed of a straight chain (hereinafter referred to as a B chain block) having no branching. In the above A chain block and A 'chain block, J and J' are in the range of 13 to 28, preferably 14 to 20. When J and J 'are less than 13, the agent is remarkably removed from the polyester fiber, the durability is inferior, and the performance varies greatly. When J and J 'exceed 28, the diffusion of the agent in the polyester is insufficient and the uniformity is inferior. In the above formula (I), m, m ′ and p are each a positive integer, preferably 10-100.

  Further, it is necessary that the polyoxyethylene ether does not cause a secondary reaction such as copolymerization with an aromatic polyester which is a substantial main component. Therefore, it is necessary that the weight average molecular weight is 5,000 or more, preferably 6,000 or more. The weight average molecular weight is 16,000 or less, preferably 15,000 or less. This is because, if an agent having an excessively long chain is used, the dispersibility of the agent in the polyester fiber is deteriorated and becomes non-uniform.

Furthermore, the polyoxyethylene-based ether needs to be contained in the polyester fiber in an amount of 2.0 to 3.0% based on the fiber weight. When the content is less than 2.0%, the cross-sectional resistance value of the obtained polyester fiber is 1.0 × 10 ¹⁰ Ω / cm or more, which is insufficient as performance. When the amount exceeds 3.0%, the durability against rubbing is inferior, and troubles due to scraping of yarn components such as white powder occur in every process, resulting in poor handling. .

  The polyester fiber of the present invention contains an organometallic sulfonate represented by the above formula (II) together with the above polyoxyethylene-based polyether. The organometallic sulfonate may be a single compound or a mixture of organosulfonic acid metal salts having various alkyl groups or alkylaryl groups. Specific examples of such organometallic sulfonates include sodium stearylsulfonate, sodium dodecylbenzenesulfonate, tetrabutylphosphonium dodecylbenzenesulfonate, and mixtures thereof.

  The content of the organometallic sulfonate is 4 to 10%, preferably 6 to 8%, based on the fiber weight. When the content of the organometallic sulfonate is less than 4%, the conductive performance of the polyester fiber becomes insufficient, and when the content exceeds 10%, the performance is hardly changed, but the obtained polyester The strength elongation of the fiber is lowered and the mechanical performance is inferior.

  In the conductive polyester fiber according to the present invention, it is necessary to include a combination of the above-mentioned two kinds of specific components, and it is difficult to obtain the conductive polyester fiber that is the object of the present invention without either one. It is difficult to achieve the objective.

  The conductive polyester fiber according to the present invention can be produced by a known melt spinning method using a polyester in which the above-described two specific components are blended. The spinning method melts the raw material polymer, discharges it from the discharge hole, and after cooling and refueling, the undrawn yarn obtained at a spinning speed of 500 to 3,000 m / min is stretched about 1.5 to 5 times. Thus, a multifilament yarn made of the desired conductive fiber can be obtained.

  The single yarn fineness of this conductive polyester fiber (multifilament yarn) is suitably 1 to 10 dtex, and the total fineness is suitably 30 to 300 dtex. The strength is preferably 2.0 to 3.5 cN / dtex, and the elongation is preferably 30 to 40%.

  The cross-sectional shape of the fiber is not limited to a normal circular shape, and may be a so-called irregular cross-section such as an ellipse, a flat shape, a triangle, a trilobal shape, and a hollow shape. Further, additives such as stabilizers and colorants may be included in the fiber as necessary.

  In order to manufacture a conductive brush using the conductive polyester fiber of the present invention, first, a pile fabric using the fiber as a pile yarn is manufactured. As a manufacturing method of a pile fabric, it can manufacture using a publicly known method. For example, in the case of a pile woven fabric, a fabric such as a moquette velvet shown in FIG. 1 can be manufactured by a known method. In this case, the conductive polyester fiber may be used only for at least the pile yarn. On the other hand, in the case of a pile knitted fabric, a fabric such as a double raschel tricot can be produced by a known method. In addition, when manufacturing a pile fabric, 2 or more types of fibers can also be used together, for example, in the range which does not impair the performance of a conductive brush, normal polyester fiber is added to the conductive polyester fiber of this invention. A pile fabric may be manufactured.

  The drawing shows an example of a conductive brush using the conductive polyester fiber of the present invention. FIG. 1 is a perspective view showing an example of a pile fabric constituting the conductive brush, and FIG. 2 is a pile constituting the conductive brush. FIG. 3 is a side view showing an example of the conductive brush of the present invention. In FIG. 2, 1 is a warp yarn of a pile fabric, 2 is a weft yarn, 3 is a base fabric, and 4 is a coating layer applied as needed. In FIG. 3, 5 indicates a pile yarn, 6 indicates a pile fabric, and 7 indicates a support.

  In order to manufacture the conductive brush of the present invention, for example, as shown in FIG. 2, the pile fabric produced by the above method is spirally wound around a column to form a brush. Thereafter, napping treatment and shearing treatment are performed to obtain a conductive brush for an image forming apparatus. Moreover, it is good also as an electroconductive brush which fixed the pile fabric to the plane.

The cross-sectional electrical resistance value (temperature 20 ° C., humidity 40 to 70% RH) of the conductive polyester fiber in the conductive brush is preferably 10 ² to 10 ¹¹ Ω / cm. Preferably, it is 10 ⁸ to 10 ¹⁰ Ω / cm at a temperature of 25 ° C. and a humidity of 40% RH. Although it differs depending on the type of image forming apparatus, it is not preferable because it is difficult to obtain uniform charging, static elimination and cleaning effects even if it is lower or higher than this.

Since the pile yarn made of the conductive polyester fiber of the present invention satisfies the above conditions,
For example, it exhibits a sufficient function as a conductive brush that can be suitably used for an image forming apparatus such as a laser printer.

  Hereinafter, the present invention will be described in more detail with reference to Examples and Comparative Examples. The index evaluation methods shown in Table 1 are as follows.

(1) Electrical resistance value of conductive fibers Using an electrical resistance measuring device, a voltage of 1,700 V was applied between 10 cm of conductive fibers, and the electrical resistance values of five cross sections under the conditions of a temperature of 25 ° C. and a relative humidity of 40%. (Ω / cm) was measured.

(2) Durability of the conductive brush JIS L1096 8.17.3 In the friction strength test of the C method (Taber type method), the load was 4.90 N, the wear wheel No. The wear durability of the conductive brush was measured with CS-17 and 500 wear times. As an evaluation method, JIS L1096 8.17.3 “c) Judgment of change in appearance” was applied mutatis mutandis and evaluated as follows.
A: No abnormality.
B: Damage or pile is slightly reduced.
C: Warp or weft is cut. Alternatively, the pile is greatly reduced.

(3) Image quality A test chart issued by the Electrophotographic Society was copied, and the image quality after one print was determined by sensory evaluation (satisfaction) and evaluated according to the following criteria.
Good: Satisfaction 75 or higher Slightly poor: Satisfaction 50 or higher and lower than 75 Poor: Less than 50

[Example 1]
A pellet obtained by mixing 2.5% by weight of polyoxyethylene glycol having a weight average molecular weight of 15,000 and 8.0% by weight of sodium alkyl sulfonate having an average carbon number of 12 to 13 with polyethylene terephthalate at a melting temperature of 295 ° C. is discharged. After 3,000 m / min of the mixed polymer discharged from the hole was drawn, it was stretched 1.5 times at a preheating roller temperature of 50 ° C. and a take-up roller temperature of 150 ° C., and 250 dtex / 40 filament conductive polyester fiber ( Multifilament yarn) was obtained. The performance of the obtained fiber is shown in Table 1.
Next, a pile woven fabric (velvet) using this fiber as a pile yarn was manufactured to produce a conductive brush. At this time, the pile fabric was designed to have a pile density of 5,000 pieces / cm ² and a pile length of 5 mm. The results are shown in Table 1.

[Comparative Example 1]
A brush was produced and processed in the same manner as in Example 1 except that 0.5% by weight of polyoxyethylene glycol and 2.5% by weight of sodium alkyl sulfonate were changed to 2.5% by weight. The results are shown in Table 1.

[Comparative Example 2]
A polyethylene terephthalate pellet containing 17.0% by weight of conductive carbon was mixed with 90.0% by weight of polyethylene terephthalate master pellets, the melt temperature was 295 ° C., and the mixed polymer discharged from the discharge holes was mixed. Winding was performed at a winding speed of 2500 m / min. The undrawn yarn was drawn 1.8 times between the supply roller and the take-off roller using a drawing apparatus installed in the order of a supply roller temperature of 80 ° C., a heater temperature of 210 ° C., and a take-up roller, and 250 dtex / 40 filaments Conductive polyester fibers were obtained. Using this fiber, a pile fabric was produced in the same manner as in Example 1 to produce a conductive brush. The results are shown in Table 1.

[Comparative Example 3]
A pile fabric was produced in the same manner as in Example 1 using a 330 dtex / 48 filament rayon filament, and a conductive brush was produced. The results are shown in Table 1.

  The conductive brush of the present invention is excellent in durability and has little variation in electric resistance value, and can be suitably used particularly for an image forming apparatus, and its industrial utility value is extremely high.

The perspective view which shows an example of the pile fabric which comprises the electroconductive brush of this invention. The front view and side view which show an example of the cross section of the pile fabric which comprises the electroconductive brush of this invention. The side view which shows the preparation example of the electroconductive brush of this invention.

Explanation of symbols

1 Warp Thread 2 Horizontal Thread 3 Base Cloth 4 Coating Layer 5 Pile Thread 6 Pile Fabric 7 Strut

Claims (3)

A fiber made of an aromatic polyester, having a conductivity with a yarn cross-sectional resistance value of 1.0 × 10 ^{8 to} 1.0 × 10 ¹¹ Ω / cm at a humidity of 40%. Polyester fiber. Containing 2.0 to 3.0% of a polyoxyethylene-based polyether having a weight average molecular weight of 5000 to 16000 represented by the following formula (I) based on the fiber weight;

And the organometallic sulfonate represented by the following formula (II) is contained 4 to 10% based on the fiber weight,

The conductive polyester fiber according to claim 1.   A conductive brush comprising the conductive polyester fiber according to claim 1 or 2 as a pile yarn.

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