JP4825042B2 - Conductive polyester fiber - Google Patents

Description

  The present invention relates to a polyester fiber comprising at least a part of a polyester containing a polyalkylene glycol as a conductive substance, having an electrical resistance value in a specific range of conductivity, and conducting performance in the length direction. (Electrical resistance value) has little variation, so it is suitable not only for clothing such as anti-static work clothes and uniforms, but also for interior and industrial materials such as curtains, as well as for electrophotographic recording type dry copying machines, facsimiles, printers, etc. The present invention relates to a conductive polyester fiber that is suitably used for the charging, neutralizing brush, and cleaner brush used.

  Fibers made of hydrophobic polymers such as polyester, polyamide, and polyolefin have many advantages such as mechanical properties, chemical resistance, and weather resistance, and are widely used not only for clothing but also for industrial materials. . However, since these fibers generate significant static electricity due to friction, etc., they attract air dust to reduce the aesthetics, or give an electric shock to the human body to cause discomfort. It may cause problems such as obstacles and flammable explosions on flammable substances. Therefore, in order to solve these problems, it has been proposed to impart conductivity to the fiber, and many studies have been made.

  Patent Document 1 describes a core-sheath type composite fiber in which a conductive component containing conductive particles such as carbon black and metal powder is wrapped with a nonconductive polymer. With such a core-sheath type composite fiber, the conductive particles are present only inside the fiber, so troubles during operation are unlikely to occur, and it is possible to obtain good operability. However, since the conductive particles exist only inside the fibers, the conductive performance is insufficient.

  On the other hand, Patent Document 2 describes a core-sheath type conductive composite fiber in which a conductive component containing conductive particles is arranged in a sheath part. Compared with the fiber described in Patent Document 1, such a conductive conjugate fiber was prone to trouble during operation, but the conductivity performance was quite satisfactory.

  In recent years, conductive yarns are often used in fields other than clothing applications, particularly in the fields of electrophotographic recording type dry copying machines, facsimiles, printers, and the like.

  Conventionally, cellulose fibers have been often used as conductive yarns used in such fields, but many have been proposed for polyester and polyamide fibers.

However, composite fibers such as Patent Documents 1 and 2 (fibers having conductive parts and non-conductive parts)
Then, since the resistance value is different between the cross section and the side surface, it is difficult to obtain a uniform electric resistance value, and it is difficult to obtain stable conductive performance. In addition, the fiber wears out during repeated use, and a part of the fiber is lost, so that it is impossible to show the same electrical resistance value as at the beginning of use, and stable conductive performance cannot be obtained over a long period of time. There was also.

  In order to solve such a problem, as shown in Patent Document 3, a single component type (not a composite fiber but a polyester conductive fiber containing carbon black in the whole fiber) is being studied. However, although carbon black has a small primary particle size, the actual particle size becomes large due to secondary aggregation and a structure structure. For this reason, the operability is remarkably deteriorated. In particular, it is difficult to obtain a fiber having a single yarn fineness of 2 dtex or less. Furthermore, there is a problem that variation in electric resistance value (variation in electric resistance value in the yarn length direction of the fiber) increases. In addition, when carbon black is used, not only the entire fiber has a black color but also there is a problem that it cannot be dyed.

Usually, in the case of a polyester-based conductive yarn containing carbon black, the electric resistance value is 1 × 10 ⁶ to 1 × 10 ⁹ Ω / cm, and if it is not within this range, it is difficult to obtain a stable electric resistance value.

However, in the fields of electrophotographic recording type dry copying machines, facsimiles, printers, etc., they are used for various purposes such as charging brushes, static elimination brushes, cleaning brushes, etc. The range of values will also be different. In particular, it is very difficult to obtain a polyester fiber having a stable electric resistance value in the region of an electric resistance value of 5 × 10 ^{8 to} 5 × 10 ¹³ Ω / cm, and it has not been developed yet. .
JP 09-143821 A WO2002 / 075030 JP 2004-183180 A

  The present invention solves the above problems, has a specific range of electrical resistance, has little variation in electrical resistance in the longitudinal direction of the fiber, and can be obtained with good operability, Technology to provide conductive polyester fibers that can be used not only for materials but also for charging brushes and cleaning brushes for electrophotographic recording type dry copying machines, facsimiles, printers, etc. This is a typical issue.

  As a result of investigations to solve the above problems, the present inventors have reached the present invention.

That is, the present invention is a multifilament composed of a plurality of single yarns, and at least a part of the single yarn components are copolymerized with 0.3 to 6.0 mol% of 5-alkali metal sulfoisophthalic acid component. Polyester having ethylene terephthalate as a main repeating unit and containing 10 to 30% by mass of polyalkylene glycol, having an electric resistance value of 5 × 10 ^{10 to} 5 × 10 ¹³ Ω / cm, and an electric resistance in the longitudinal direction of the fiber The gist of the conductive polyester fiber is characterized in that the variation in values (standard deviation) is 0.3 or less .

  The conductive polyester fiber of the present invention has an electrical resistance value in a specific range, has little variation in electrical resistance value in the longitudinal direction of the fiber, can be obtained with good operability, and has excellent color tone. It can be suitably used not only for materials but also for charging brushes and cleaning brushes for electrophotographic recording type dry copying machines, facsimiles, printers, and the like.

  The conductive polyester fiber of the present invention is a multifilament composed of a plurality of single yarns, and the single yarns are made of polyester. The polyester constituting the single yarn is a polyester (referred to as polyester A) containing ethylene terephthalate as a main repeating unit and containing 10 to 30% by mass of polyalkylene glycol.

  That is, the single yarn constituting the fiber of the present invention may be either a polyester A only (single component type) or a polyester A and another component (composite type). . In the case of a composite type fiber, a core-sheath type composite fiber in which polyester A is arranged as a sheath component, and a sea-island type composite fiber in which polyester A is arranged as an island component and at least a part of which is exposed on the fiber surface It is preferable to do. Examples of other components include polyester, polyamide, polyolefin, and the like, but it is preferable to use polyester.

  Above all, when the fibers of the present invention are used in electrification, static elimination brushes, cleaner brushes used in electrophotographic recording type dry copying machines, facsimiles, printers, etc., the fibers wear out during repeated use. Therefore, it is preferable to use a single-component fiber as one that can have the same conductive performance as that at the beginning of use even if a part of the fiber is lost.

  In the fiber of the present invention, polyalkylene glycol is used as a conductive component, and since carbon black that is usually used is not used, there is no loss of carbon black due to wear, and there is no scattering of carbon black to the outside. . For this reason, the dispersion | variation (standard deviation) of the electrical resistance value of the longitudinal direction of a fiber is small, and uniform electroconductivity can be maintained for a long period of time. Further, since the color tone is good and dyeing is possible, it can be used for various purposes.

  Polyester A contains ethylene terephthalate as the main repeating unit and contains 10 to 30% by mass of polyalkylene glycol, preferably 12 to 28% by mass. Examples of the polyalkylene glycol include polyethylene glycol, polypropylene glycol, and polytetramethylene glycol. The molecular weight of the polyalkylene glycol is not particularly limited, but a molecular weight of 300 to 10,000 is preferable.

  These polyalkylene glycols may be copolymerized or may lose copolymerization due to end capping. When copolymerized, two or more types of random copolymers or block copolymers may be used.

Thus, in the present invention, by using a polyester containing an optimal amount of polyalkylene glycol as a conductive component, the electrical resistance value is 5 × 10 ^{10 to} 5 × 10 ¹³ Ω / cm, and the length of the fiber A polyester fiber having a variation (standard deviation) in electrical resistance value in the direction of 0.3 or less can be obtained.

That is, usually, the electrical resistance value of the polyester conductive yarn containing carbon black is determined by the conductive properties of the carbon black used, the carbon concentration in the fiber, and the properties of the polyester, but 1 × 10 ⁶ to 1 × 10. Unless the region is ⁹ Ω / cm, it is difficult to obtain stable conductive performance (small variation in electrical resistance value in the longitudinal direction of the fiber). In particular, the electrical resistance value required for use in electrification, static elimination brushes, cleaner brushes, etc. used in electrophotographic recording type dry copying machines, facsimiles, printers, etc. is 5 × 10 ^{10 to} 5 × 10 ¹³ Ω / In the cm region, it was very difficult to obtain stable conductive performance.

In the present invention, by using a polyalkylene glycol which is a hydrophilic group instead of using carbon black which is a conductive component, the electrical resistance value is stable in the region of 5 × 10 ^{10 to} 5 × 10 ¹³ Ω / cm. Thus, a conductive polyester fiber having an electrical resistance value can be obtained.

  In addition, the electrical resistance value of the conductive polyester fiber in the present invention was obtained by collecting 20 test pieces having a length of 10 cm every 100 m in the fiber length direction, and 500 V between these 10 cm test pieces (between both ends). A voltage is applied, and measurement is performed using a resistance measuring device “SM-10E” manufactured by Toa Denpa Kogyo Co., Ltd. under conditions of a measurement environment of 20 ° C. and 20% RH. And it is set as the average value of 20 test pieces.

  In addition, the standard deviation, which is an index indicating the variation in the electrical resistance value in the longitudinal direction of the conductive polyester fiber in the present invention, is obtained by collecting 500 test pieces as described above (500 points is 500 test pieces). In the same manner as described above, the electrical resistance value is measured, and the standard deviation is calculated.

When the content of polyalkylene glycol in the polyester A is less than 10% by mass, the hydrophilic group is insufficient, so that the electrical resistance value is increased, and a polyester having a range of 5 × 10 ^{10 to} 5 × 10 ¹³ Ω / cm is obtained. I can't.

On the other hand, when the content of polyalkylene glycol in the polyester A exceeds 30% by mass, the amount of hydrophilic groups in the polyester fiber is excessively increased, so that the moisture dependency is increased and the electrical resistance value in the longitudinal direction of the fiber varies. (Standard deviation) exceeds 0.3.
Furthermore, the melting point is remarkably lowered and the heat resistance is not only inferior, but the operability is also deteriorated.

In polyester A, it is preferable that a 5-alkali metal sulfoisophthalic acid component is copolymerized in an amount of 0.3 to 6.0 mol%. By copolymerizing the above components, the electrical resistance value is further stabilized.

That is, by copolymerizing the polar group of the 5-alkali metal sulfoisophthalic acid component with polyester A, moisture can be easily taken into the fiber, so that a stable electric resistance value can be obtained.

When the amount of the 5-alkali metal sulfoisophthalic acid component is less than 0.3 mol%, the effect of the polar group is reduced. On the other hand, if it exceeds 6.0 mol%, polyester A is thickened, so that not only the operability is deteriorated but also the fiber strength is remarkably lowered.

Among the compounds used as the 5-alkali metal sulfoisophthalic acid component, particularly preferred are sodium 3,5-di [carbomethoxy] benzenesulfonate (or potassium or lithium), 3,5-di [β -Hydroxyethoxycarbonyl] sodium benzenesulfonate [or potassium or lithium] and the like.

  Further, in the polyester A of the present invention, a crystal nucleating agent such as talc or mica may be added in order to improve crystallinity.

  Furthermore, a third component may be contained (copolymerized or blended) in the conductive polyester fiber of the present invention as long as the effects of the present invention are not impaired. Such third components include phthalic acid, isophthalic acid, 5-alkali metal isophthalic acid, naphthalenedicarboxylic acid, diphenyldicarboxylic acid, diphenoxyethanedicarboxylic acid, adipic acid, sebacic acid, azelaic acid, decanedicarboxylic acid, cyclohexane And dicarboxylic acid components such as dicarboxylic acid. And these may be used individually by 1 type and may use 2 or more types together.

  And it is preferable that the electroconductive polyester fiber of this invention does not contain carbon black. Although carbon black has a small primary particle size, the actual particle size becomes large by exhibiting secondary aggregation and a structure structure. For this reason, there is a problem that the operability is remarkably deteriorated. In particular, it is difficult to obtain a fiber having a single yarn fineness of 2 dtex or less.

  Therefore, the conductive polyester fiber of the present invention can obtain a single yarn fineness of 2 dtex or less with good operability, and also has a very good color tone, can be dyed, and can be used for any application. It becomes possible.

  Among them, the conductive polyester fiber of the present invention preferably has an L value indicating the color tone of the fiber of 50 or more, and more preferably 60 or more. The L value in the present invention is a value obtained by measuring the conductive polyester fiber of the present invention with a color difference meter CR-300 manufactured by MINORUTA. If the L value is less than 50, the color tone will be inferior and dyeing will be difficult, making it difficult to use for many purposes.

The conductive polyester fiber of the present invention is preferably used for a charging brush, a static eliminating brush, a cleaning brush, etc. in the field of electrophotographic recording type dry copying machines, facsimiles, printers, etc. From the standpoint of properties, the single yarn fineness is preferably 0.5 to 4.0 dtex. Among them, the single yarn fineness is preferably 1.5 to 3.5 dtex.
The number of single yarns is not particularly limited, but is preferably 10 to 200.

Next, the present invention will be described more specifically with reference to examples. Measuring methods and evaluation methods for various values in the examples are as follows.
1. Electric resistance value It measured by said method.
2. Dispersion of electric resistance value (standard deviation)
It measured by said method.
3. Color tone (L value)
It measured by said method.
4). Operability
Spinning was performed continuously for 24 hours, and the evaluation was made in the following three stages according to the number of cut yarns (per spindle) during this period.
○: No cutting thread △: Cutting thread 1 to 2 times ×: Cutting thread 3 or more times

Example 1
A slurry of terephthalic acid and ethylene glycol having a molar ratio of 1 / 1.6 is continuously fed to an esterification reaction vessel in which bis (β-hydroxyethyl) terephthalate and its low polymer (BHET) are present, at a temperature of 250 ° C. The esterification reaction was carried out under conditions of a pressure of 0.05 kg / cm ² and a residence time of 8 hours, and BHET having an esterification reaction rate of 95% was continuously obtained. Transfer 50 kg of this BHET to the polymerization tank, add polyethylene glycol having a number average molecular weight of 6000 and sodium 5-sulfoisophthalate, and then heat to 275 ° C., and antimony trioxide as a catalyst and triethyl phosphate as a phosphorus compound. Then, a polycondensation reaction was performed under reduced pressure by a conventional method to obtain polyester A. Polyester A contains 15% by mass of polyethylene glycol having an intrinsic viscosity of 0.64 (measured at a temperature of 20 ° C. using an equimolar mixture of phenol and ethane tetrachloride as a solvent), and 1 mol of sodium 5-sulfoisophthalate. Polymerized polyethylene terephthalate, which was chipped by a conventional method.
The chip was dried by a conventional method, then supplied to an extruder at 270 ° C., and melt spinning was carried out using a normal melt spinning apparatus (36 spin holes having a hole diameter of 0.25 mm were formed in the spinneret). The spun yarn was cooled by an air flow, passed through an oiling device, and an oil agent was applied so that the amount of adhesion was 0.5% by mass. Subsequently, the film was taken up with a roller having a speed of 800 m / min, wound with a winder, and an undrawn yarn of 264 dtex / 36 f was obtained. The undrawn yarn was drawn 2.64 times between 95 ° C. heat rollers, further heat treated with a 180 ° C. heat plate, and wound to obtain 100 dtex / 36 f conductive polyester fiber.

Examples 2-3 and Comparative Examples 1-3
The same procedure as in Example 1 was conducted except that the content of polyethylene glycol in polyester A was changed as shown in Table 1.

Examples 4-5
The same procedure as in Example 2 was conducted except that the content of sodium 5-sulfoisophthalate in polyester A was changed as shown in Table 1.

Example 6
The same procedure as in Example 1 was performed except that a spinneret having 72 spinning holes having a hole diameter of 0.2 mm was used.

Example 7
The same procedure as in Example 1 was conducted except that the discharge amount was changed to obtain a 56 dtex / 72 f conductive polyester fiber.

Comparative Example 4
Carbon black was melt-kneaded to a polyethylene terephthalate chip having an intrinsic viscosity of 0.68 obtained by a conventional polycondensation reaction so as to be 20% by mass, and the chip was formed by a conventional method to obtain a conductive chip. After the conductive chip was dried by a conventional method, a 56 dtex / 72f conductive polyester fiber was obtained in the same manner as in Example 7.

  Table 1 shows the characteristic values and evaluation of the conductive polyester fibers obtained in Examples 1 to 7 and Comparative Examples 1 to 4.

As is apparent from Table 1, the conductive polyester fibers obtained in Examples 1 to 7 can be obtained with good operability and have an electric resistance value in the range of 5 × 10 ^{10 to} 5 × 10 ¹³ Ω / cm. In addition, the variation in electric resistance value was small, and it had stable conductive performance. Further, the L value was 50 or more, and the color tone was excellent.
On the other hand, since the conductive polyester fiber of Comparative Example 1 had a low content of polyethylene glycol in polyester A, the conductive performance was poor and measurement was impossible. Since the conductive polyester fiber of Comparative Example 2 contained a large amount of polyethylene glycol in polyester A, the electrical resistance value varied greatly. The conductive polyester fiber of Comparative Example 3 was not only poor in operability because of the excessive polyethylene glycol content in polyester A, but also had a large variation in electrical resistance value. Since the conductive polyester fiber of Comparative Example 4 contained carbon black, the L value was low, the color tone was inferior, and the operability was also poor.

Claims (2)

A multifilament composed of a plurality of single yarns, wherein at least a part of the single yarn components are mainly repeating units of ethylene terephthalate copolymerized with 0.3 to 6.0 mol% of 5-alkali metal sulfoisophthalic acid component And a polyester containing 10 to 30% by mass of polyalkylene glycol, having an electric resistance value of 5 × 10 ^{10 to} 5 × 10 ¹³ Ω / cm, and variations in the electric resistance value in the longitudinal direction of the fiber (standard deviation) ) Is 0.3 or less, a conductive polyester fiber. The conductive polyester fiber according to claim 1, wherein an L value indicating a color tone of the fiber is 50 or more.