JP5070991B2 - Conductive yarn with crimp - Google Patents

Description

  The present invention provides a multi-layer composed of a composite fiber in which a conductive layer and a non-conductive layer having fiber-forming properties form a side-by-side composite or an eccentric core-sheath composite, and the conductive layer forms at least a part of the fiber surface. A filament, wherein the multifilament relates to a conductive yarn having a coil crimp. More specifically, when used in a conductive brush of an image forming apparatus (copying machine, printer, etc.) due to fine coil crimping of the conductive yarn, it exhibits excellent static elimination performance and toner cleaning performance, When used in part, the present invention provides a conductive yarn having antistatic performance superior to that of conventional products.

  Conventional conductive fibers that have been proposed as conductive brushes for image forming devices have a conductive layer made of thermoplastic polymer containing carbon black. The higher the carbon black content, the lower the fluidity of the polymer. (It is difficult to deform), and it is known that the spinnability is also lowered. When carbon black is contained in a polyester generally used as a synthetic fiber, for example, a polyester component in which the main repeating structural unit is composed of ethylene terephthalate, if carbon black is contained at a high concentration (20% by weight or more), The yarn property is extremely lowered and the yarn breakage occurs frequently and cannot be taken out stably. In view of this, several composite fibers have been proposed in which a fiber-forming polymer is arranged in a non-conductive layer for the purpose of supplementing the spinnability, and the conductive layer is exposed on a part of the fiber surface.

  For example, a core-sheath composite fiber having polyethylene terephthalate containing 25% by weight of carbon black as a sheath component and polyethylene terephthalate not containing carbon black as a core component has been proposed (Patent Document 1).

  However, although the conductive fiber of Patent Document 1 has improved spinnability as compared with the fiber consisting only of the conductive layer, it has a high frequency of thread breakage and has large conductive spots in the longitudinal direction of the fiber. Even when processed into a conductive brush, the sharpness of printing and toner cleaning properties were poor.

Polyamide, on the other hand, is used in many conductive fibers because even if it contains carbon black at a high concentration (20 to 35% by weight), the decrease in fluidity is not as remarkable as that of polyester and it exhibits relatively good spinnability. ing. For example, a core-sheath composite fiber has been proposed in which a polyamide containing 35% by weight of carbon black is used as a sheath component and a thermoplastic polymer having a melting point of 170 ° C. or higher is used as a core component (Patent Document 2).
However, since the conductive fiber of Patent Document 2 uses a hygroscopic polyamide in the conductive layer, it has a problem that the change in conductivity accompanying the change in temperature and humidity is large. For this reason, when used as a brush for cleaning a photoconductor mounted on an image forming apparatus, there has been a problem that toner cleaning performance is gradually lowered and recording image quality is lowered after a long run.

  Furthermore, in any technique, when used as a conductive brush, streaks due to charged spots are likely to appear in the axial direction of the brush, exhibiting highly uniform charge removal performance, that is, excellent toner cleaning properties. It was difficult.

Therefore, in order to increase toner cleaning performance, conductive fibers are proposed in which the fibers are flattened by false twisting to increase the contact area with the photosensitive member of the image forming apparatus. Patent Document 3). However, when the conductive fiber of Patent Document 3 contains a high concentration of carbon black, the ductility is low as in Patent Document 1, and thus yarn breakage easily occurs. Further, the processing tension at the time of false twisting is not stable, so the quality is low. Only the crimped yarn was obtained. Therefore, even if the conductive brush of the image forming apparatus is processed, the quality of the brush is poor, and the sharpness of printing and the toner cleaning property are inferior. Further, when polyamide is used, as in Patent Document 2, there is a problem that the change in conductivity accompanying the change in temperature and humidity is large, and it is necessary to clean the photoreceptor mounted on the image forming apparatus. When used for a brush, there has been a problem that the toner cleaning property is gradually lowered and the recording image quality is lowered.
WO2002 / 075030 (Example) JP 2002-235245 A (Claims) JP 2006-336142 A (Claims)

  The object of the present invention is to solve the above-mentioned problems of the prior art, and not only has high conductivity and environmental adaptability (low temperature / humidity dependency of the conductive properties) in the yarn length direction, It is an object of the present invention to provide a conductive yarn that can suppress a decrease in toner cleaning performance on a photoreceptor during long-time running by providing coil crimping.

Containing carbon black, a conductive layer made of a polyester main repeating structural unit is a propylene terephthalate, and non-conductive layer made of a polyester having a fiber formability forms a side-by-side composite or eccentric core-sheath composite, The conductive layer is a multifilament composed of a composite fiber in which at least a part of the fiber surface is formed, the volume specific resistance P in the yarn length direction is 10 ⁻¹ to 10 ⁷ Ω · cm, and the CR value is 3 to 3. The conductive yarn is 50%.

Containing carbon black, the temperature and humidity of the main repeating a conductive layer structural unit of polyester is propylene terephthalate by exposing the surface of the fiber, high conductivity in the yarn length direction and environmental compatibility (conductive properties It is to provide a conductive yarn that can improve the toner cleaning property on the photosensitive member for a long time running by not only having a small dependency) but also providing the fiber with a fine coil crimp. .

Fibers of the present invention, containing carbon black, polyester (hereinafter referred to as "polypropylene terephthalate" or "PPT") main repeating structural unit is a propylene terephthalate has whether Ranaru conductive layer, conductive layer Forms at least part of the fiber surface. When carbon black was contained at a high concentration in conventional polyethylene terephthalate (hereinafter referred to as “PET”), only a conductive yarn with very poor spinnability and large conductive spots in the longitudinal direction of the yarn was obtained. In contrast, by using the PP T of the present invention in the matrix polymer of the conductive layer improves spinnability drastically, highly uniform fiber diameter of the thread longitudinal direction, also reduced dispersion plaques carbon black The present inventors have found that. This is because the high affinity of the specific carbon black PP T among polyester. This way PP T cause is not clear showing of carbon black with high affinity, it is believed to be caused by the molecular form of the polyester. That is, it is known that PPT has a structure in which the methylene chain is bent greatly and the molecular chain forms a helix, and this helix structure makes it difficult for the benzene rings to stack, and restrains the intermolecular chain. It is thought that carbon black tends to enter between molecular chains because of its low nature . Et al is a polyester of a certain or more weight average molecular weight, i.e., weight average molecular weight Mw to use a PP T is 75,000～500,000, hardly viscous break be excessive spinning tension load It is preferable because almost no thinness is generated in the yarn longitudinal direction, that is, uniform conductivity is obtained in the yarn longitudinal direction. More preferably, it is 80,000-400,000, More preferably, it is 90,000-300,000. If the molecular weight exceeds 500,000, the polymerization time is long and the production cost is high, and the piping design of the spinning device due to the high melt viscosity becomes difficult, so the cost performance is significantly reduced. Furthermore, if the weight average molecular weight Mw is 500,000 or less, the molecular orientation in the stretching process can be increased, so that a conductive fiber having practical strength can be obtained. In order to obtain higher fiber strength, it is preferably 400,000 or less, and more preferably 300,000 or less.

  In melt spinning without the addition of carbon black, the weight average molecular weight is generally increased and the extensional viscosity is increased. However, when carbon black is added at a high concentration, the extensional viscosity is hardly increased even if the weight average molecular weight is increased. It was the first time that a unique behavior was found. For this reason, the fiber of the present invention improves only the durability against viscous fracture without changing the extensional viscosity, and improves the uniformity of electrical conductivity in the longitudinal direction of the yarn.

Moreover, it is preferable that dispersion degree Mw / Mn which took the ratio of the weight average molecular weight Mw and the number average molecular weight Mn is 1.5-6. By setting the dispersity Mw / Mn to 6 or less, the dispersibility of the carbon black is increased, the melt viscosity during melt spinning is stabilized, and good spinnability is imparted. That is, uniform conductivity is obtained in the longitudinal direction of the yarn . Min plastid Mw / Mn is preferably from 1.6 to 5, more preferably from 1.8 to 4. Polyester component used in the conductive layer is mainly PP T that consists. The PPT is a polymer formed by an esterification reaction of terephthalic acid, which is a carboxylic acid, and trimethylene glycol, which is an alcohol, and contains 50 mol% or more of propylene terephthalate units. In order to have affinity with carbon black, the propylene terephthalate unit is preferably 80 mol% or more, and more preferably 95 mol% or more .
The PPT may be copolymerized with other components within the scope of the gist of the present invention, that is, high melt spinnability when carbon black is contained at a high concentration. For example, a copolymer of a dicarboxylic acid compound is copolymerized. It can be shown. Examples of the dicarboxylic acid compound include isophthalic acid, naphthalene dicarboxylic acid, diphenyl dicarboxylic acid, anthracene dicarboxylic acid, phenanthrene dicarboxylic acid, diphenyl ether dicarboxylic acid, diphenoxyethanedicarboxylic acid, diphenylethanedicarboxylic acid, adipic acid, sebacic acid, 1,4 -Aromatic, aliphatic and alicyclic dicarboxylic acids such as cyclohexanedicarboxylic acid, 5-sodium sulfoisophthalic acid, 5-tetrabutylphosphonium isophthalic acid, azelaic acid, dodecanedioic acid, hexahydroterephthalic acid, and their alkyl, alkoxy , Derivatives, adducts, structural isomers and optical isomers such as allyl, aryl, amino, imino and halide, and one of these dicarboxylic acid compounds May be used in Germany, or spirit may be used in combination of two or more in a range that does not impair the invention. Also, a diol compound can be copolymerized. Examples of the diol compound include ethylene glycol, tetramethylene glycol, pentanediol, hexanediol, 1,4-cyclohexanedimethanol, neopentyl glycol, hydroquinone, resorcin, dihydroxybiphenyl, Aromatic, aliphatic, alicyclic diol compounds such as naphthalenediol, anthracenediol, phenanthrenediol, 2,2-bis (4-hydroxyphenyl) propane, 4,4′-dihydroxydiphenyl ether, bisphenol S, and alkyls thereof, Derivatives, adducts, structural isomers, and optical isomers such as alkoxy, allyl, aryl, amino, imino, and halide can be mentioned. Among these diol compounds May be used seeds alone or spirit it may be used in combination of two or more in a range that does not impair the present invention. Examples of the copolymer component include a compound having a hydroxyl group and a carboxylic acid in one compound, that is, a hydroxycarboxylic acid. Examples of the hydroxycarboxylic acid include lactic acid, 3-hydroxypropionate, 3 Aromatic, aliphatic and alicyclic diol compounds such as hydroxybutyrate, 3-hydroxybutyrate valerate, hydroxybenzoic acid, hydroxynaphthoic acid, hydroxyanthracenecarboxylic acid, hydroxyphenanthrenecarboxylic acid, (hydroxyphenyl) vinylcarboxylic acid And derivatives, adducts, structural isomers and optical isomers such as alkyl, alkoxy, allyl, aryl, amino, imino, and halides, and one of these hydroxycarboxylic acids can be used alone. It ’s good, Others may be used in combination of two or more in a range that does not impair the gist of the invention. In the fiber of the present invention, the conductive layer and a non-conductive layer made of polyester having fiber form form a composite structure. The “conductive layer” and “non-conductive layer” referred to here are separately prepared “conductive component” (carbon black-containing polymer) and “non-conductive component” (carbon black-free polymer; limited to one component). In a composite fiber composed of two or more components), a portion made of a conductive component with a composite interface as a boundary is called a “conductive layer”, and a portion made of a non-conductive component is called a “non-conductive layer”. . Since the melting point of PPT which is the main component of the conductive layer of the present invention is 225 to 230 ° C., it is preferable to perform melt spinning at a temperature range in which good spinnability is obtained, that is, at a temperature close to the melting point of the polyester. . Therefore, the nonconductive component forming the core is preferably a fiber-forming polyester having a melting point of 210 to 250 ° C, and more preferably 220 to 245 ° C. Here, the fiber-forming polyester can include, for example, a polymer formed from an ester bond of a dicarboxylic acid compound and a diol compound. As the polymer according to these, the main repeating structural unit is ethylene terephthalate, propylene terephthalate, Examples thereof include polyesters such as butylene terephthalate, ethylene naphthalate, propylene naphthalate, tetramethylene naphthalate or cyclohexanedimethanol terephthalate, and liquid crystal polyesters having molten liquid crystallinity mainly composed of aromatic hydroxycarboxylic acid.

  Although not particularly limited, the polyester polymer formed from the ester bond of the dicarboxylic acid compound and the diol compound may be copolymerized with other components as long as the gist of the present invention is not impaired. For example, a dicarboxylic acid compound can be copolymerized. Examples of the dicarboxylic acid compound include terephthalic acid, isophthalic acid, naphthalenedicarboxylic acid, diphenyldicarboxylic acid, anthracene dicarboxylic acid, phenanthrene dicarboxylic acid, diphenyl ether dicarboxylic acid, diphenoxyethanedicarboxylic acid, diphenylethanedicarboxylic acid, adipic acid, sebacic acid, 1,4-cyclohexanedicarboxylic acid, 5-sodium sulfoisophthalic acid, 5-tetrabutylphosphonium isophthalic acid, azelaic acid, dodecanedioic acid, hexahydroterephthalic acid, aromatic, aliphatic and alicyclic dicarboxylic acids and their Derivatives, adducts, structural isomers and optical isomers such as alkyl, alkoxy, allyl, aryl, amino, imino, halide, etc. One kind may be used alone, or spirit may be used in combination of two or more in a range that does not impair the inventions of.

  Further, as a copolymer component of the polyester polymer, a diol compound can be copolymerized. Examples of the diol compound include ethylene glycol, propylene glycol, tetramethylene glycol, pentanediol, hexanediol, and 1,4-cyclohexanediene. Aromatics such as methanol, neopentyl glycol, hydroquinone, resorcin, dihydroxybiphenyl, naphthalenediol, anthracenediol, phenanthrenediol, 2,2-bis (4-hydroxyphenyl) propane, 4,4′-dihydroxydiphenyl ether, bisphenol S, Aliphatic, alicyclic diol compounds and their derivatives such as alkyl, alkoxy, allyl, aryl, amino, imino, halides, adducts, structural differences Can be mentioned body and optical isomers, one of may be used alone, or spirit may be used in combination of two or more in a range that does not impair the inventions of these diol compounds.

  Examples of the copolymer component of the polyester polymer include a compound having a hydroxyl group and a carboxylic acid in one compound, that is, a hydroxycarboxylic acid. Examples of the hydroxycarboxylic acid include lactic acid and 3-hydroxy Aromatic, aliphatic such as propionate, 3-hydroxybutyrate, 3-hydroxybutyrate valerate, hydroxybenzoic acid, hydroxynaphthoic acid, hydroxyanthracenecarboxylic acid, hydroxyphenanthrenecarboxylic acid, (hydroxyphenyl) vinylcarboxylic acid, Examples thereof include alicyclic diol compounds and their derivatives such as alkyl, alkoxy, allyl, aryl, amino, imino, and halides, adducts, structural isomers, and optical isomers. Among these hydroxycarboxylic acids, The may be used alone, or spirit may be used in combination of two or more in a range that does not impair the invention.

  The polyester polymer may be a polymer in which one compound such as aromatic, aliphatic, alicyclic, etc. is mainly composed of a hydroxycarboxylic acid compound having both a carboxylic acid and a hydroxyl group. Examples of the polymer comprising hydroxycarboxylic acid include polyesters having hydroxycarboxylic acid as a main repeating structural unit such as lactic acid, 3-hydroxypropionate), 3-hydroxybutyrate), 3-hydroxybutyrate valerate). In addition, these hydroxycarboxylic acids include aromatic, aliphatic, and alicyclic dicarboxylic acids, or aromatic, aliphatic, and alicyclic diol components as long as they do not impair the spirit of the present invention. May be used, or plural kinds of hydroxycarboxylic acids are copolymerized. Good.

Since the main component of the conductive layer of the present invention is a PP T, in order to improve the adhesion between the conductive layer is preferably a core portion made of a non-conductive layer is also fiber-forming polyesters. Among them, the polyester having particularly excellent adhesion, polyester or mainly composed of PP T, isophthalic acid (hereinafter referred to as "IPA") and 2.2-bis (4- (2-hydroxyethoxy) phenyl) propane (Hereinafter referred to as “BPA-EO”), polyester obtained by copolymerization of adipic acid, azelaic acid and sebacic acid (hereinafter referred to as “copolymerized PET”) is preferably used. As the copolymerized PET, BPA-EO or adipic acid is particularly preferably copolymerized to improve the adhesiveness with the conductive layer. As a copolymerization ratio, 1-15 mol% is preferable and 2-10 mol% is more preferable. Further, IPA may be copolymerized together with the BPA-EO and adipic acid. By copolymerizing the copolymer component with polyester, the melting point of the polymer can be lowered. That is, the spinning temperature can be lowered. Here, in order to dispose the conductive layer outside the coil crimp, it is necessary to make the nonconductive layer highly contracted. In this case, it is effective to lower the crystallinity of the nonconductive layer. That is, it is preferable to use IPA copolymerization or BPA-EO as a copolymerization component. On the other hand, when the conductive component is arranged inside the coil, it is necessary to make the nonconductive layer low contraction. In this case, it is effective to increase the crystallinity of the nonconductive layer. That is, it is preferable to use adipic acid or azelaic acid as a copolymerization component. As an advantage when the conductive layer is arranged inside the coil, the dimensional stability is improved, and the elastic recovery property of the conductive layer (PPT ) is high, so that the crimp is not easily lost. As a result, it is possible to maintain good cleaning performance even when used for a long time. Examples of the carbon black used in the conductive layer include furnace black obtained by a furnace method, ketjen black obtained by a ketjen method, and acetylene black using acetylene gas as a raw material. In addition, graphite, carbon fiber and the like are also preferably used. For the conductive layer of the present invention, it is more preferable to use furnace black, ketjen black, or acetylene black, which are conductive carbon blacks. Among these conductive carbon blacks, furnace black and surface functional groups that have a wide control range of particle diameter (specific surface area), structure, and surface properties (chemical properties of the particle surface), which are basic properties of carbon black conductive performance. Particularly preferred is acetylene black which has a low dispersibility and excellent dispersibility. The conductive performance of the conductive carbon black is preferably as low as the volume resistivity, more preferably 5.0 × 10 ³ Ω · cm or less, and 1.0 × 10 ^{−6 to} 5.0 × 10. More preferably, it is ² Ω · cm. Further, when included in the fiber of the present invention, the average particle size of primary particles of the conductive carbon black is 1 to 100 nm in order to form a structure as a conductive circuit without impairing the mechanical properties of the fiber. is preferably in the range, also dibutyl phthalate absorption amount of structure is preferably in the range of 30~600cm ³ / 100g, it is more preferred 35~400cm ³ / 100g. The dibutyl phthalate absorption is, the higher structure develops large, conductive exceeds 600 cm ^3/100 g is improved, the fluidity of the conductive layer spinnability is lowered to deteriorate. Moreover, the functional group on the surface of carbon black is derived from the atmosphere in the process of producing carbon black. For example, the amount of hydrogen is related to the temperature and time during production. The amount of hydrogen in furnace black used in the present invention is preferably 0.1 to 0.4%. In order to identify or quantify the functional group on the surface, it is possible to examine the volatile composition, volatile content, pH, and the like.

  In the fiber of the present invention, the conductive layer and the non-conductive layer form a side-by-side composite or an eccentric core-sheath composite in order to give the fiber a fine coil crimp. By making polymers having different viscosities into the composite form, stress concentrates on the high viscosity side during spinning and stretching, so that the internal strain differs among the components. Therefore, the high-viscosity side contracts greatly due to the difference in elastic recovery rate after stretching and the heat shrinkage rate difference in the heat treatment process of higher-order processing, and distortion occurs in the single fiber to take a form of three-dimensional coil crimp. It can be said that the diameter of the three-dimensional coil and the number of coils per unit fiber length are determined by the shrinkage difference between the high shrinkage component and the low shrinkage component (the value obtained by adding the elastic recovery rate difference and the heat shrinkage rate difference). As the shrinkage difference increases, the coil diameter decreases and the number of coils per unit fiber length increases. The shrinkage difference can be controlled by selecting the copolymer component and controlling the crystallinity of the polyester.

  Furthermore, the fiber of the present invention is a composite fiber in which a conductive layer is exposed on at least a part of the fiber surface in order to increase the electrical conductivity on the fiber surface. By exposing the conductive layer on the fiber surface, a conductive path is formed on the fiber surface, and electrons are transferred quickly even at a low voltage.

  When the fiber of the present invention is a side-by-side composite, the conductive layer can be made highly conductive if it is arranged outside the coil crimp, and can be made low conductive by being arranged inside.

For the conductive performance of the conductive yarn used in the present invention, the volume resistivity needs to be 10 ⁻¹ to 10 ⁷ Ω · cm. The smaller the volume resistivity is, the higher the conductivity is and the easier it is for electricity to flow. Therefore, depending on the application, high conductivity (low volume resistivity) is required. In the present invention, since the amount of carbon black that can be contained in PPT and PBT to the maximum is 40% by weight, the lower limit of the volume resistivity is 10 ⁻¹ Ω · cm. By being in the range of the volume specific resistance, it is possible to sufficiently reach the level of electrical conductivity that makes it possible to eliminate static electricity or prevent charging as a conductive brush. When the conductive yarn of the present invention is used for the conductive brush of the image forming apparatus, the volume resistivity is preferably in the range of 10 ⁰ to 10 ⁶ Ω · cm, depending on the characteristics of the apparatus and the role of the conductive brush. A conductive fiber having an optimal volume resistivity may be used.

The volume resistivity can be controlled by the type of carbon black (mainly conductive properties), the concentration of carbon black, the single fiber fineness, the ratio of the exposed length of the conductive layer in the fiber cross section, the thickness of the conductive layer, and the like. is there. The carbon black content for obtaining the volume resistivity is preferably 15 to 40% by weight, more preferably 20 to 35% by weight. When the content is 15% by weight or more, the conductive performance becomes obvious due to the formation of the carbon structure. When the content is 20% by weight or more, the conductive performance is rapidly improved. Moreover, when the carbon black content is 40% by weight or less, good spinnability is obtained, and uniform conductivity is obtained in the longitudinal direction of the yarn. The formation of a structure is essential. In order to obtain high electrical conductivity, the structure must be dispersed in the polymer without breaking and be present in high density while maintaining long bonds. As a means for this, in the drawing process, it is possible to stretch the structure in the longitudinal direction of the fiber while suppressing breakage of the structure by drawing in the vicinity of the natural drawing ratio of the undrawn yarn (hereinafter referred to as “NDR”). Become. The draw ratio is also effective for controlling the degree of coil crimp, that is, the CR value in the present application. In our study, NDR × 0.9 to NDR × 1.3 times is preferable. That is, if NDR is 2 times, it may be drawn by 1.8 to 2.6 times, and if the natural drawing ratio is 3 times, it may be drawn by 2.7 to 3.9 times. A more preferable draw ratio is NDR × 0.95 to 1.25 times, and further preferably NDR × 1.0 to 1.2 times. NDR can be obtained from the constant tension elongation range elongation by the following equation.

NDR (times) = 1 + (constant tension elongation range elongation (%) / 100)
The carbon structure can also be controlled by controlling the heat treatment temperature. By increasing the heat treatment temperature or lengthening the heat treatment time, the crystallization of the polyester component in the conductive layer is promoted, and the structure is localized and densified by eliminating carbon black from the crystal part. Will improve. The heat treatment method is not particularly limited, and a hot roll or hot plate during drawing, a method of aging a package of undrawn yarn or drawn yarn with a dryer, a heat treatment may be performed after making a brush or fabric.

  In the conductive yarn of the present invention, the ratio ESR (ESR = Q / P) between the volume specific resistance P in the yarn length direction and its standard deviation Q is preferably 0.3 or less. ESR is an index of conductive spots in the yarn length direction, and the smaller the value, the smaller the conductive spots. Therefore, it can be said that ESR is a high-quality conductive thread. In particular, when used for a conductive brush of an image forming apparatus, it has been found that the correlation between ESR and printing spots is high, and in order to obtain higher quality printing characteristics, the ESR is more preferably 0.2 or less. 0.08 or less is more preferable. In order to reduce the ESR, it is effective to reduce the fineness unevenness in the yarn length direction.

Improves fiber-forming ability by using a PP T of the present invention in the matrix polymer of the conductive layer, since the uniformity of the fiber diameter of the yarn lengthwise direction is increased, the dispersion plaques carbon black is reduced. That is, since the polyester specifically has high affinity with carbon black, the conductive spots in the yarn length direction can be reduced.

The conductive yarn of the present invention needs to be a multifilament composed of fibers having coil crimps. Conventionally, it has been difficult to crimp a polyester conductive yarn to which carbon black has been added. Further, even if the crimped yarn has unevenness in the crimped quality, only a product having a stable conductive performance can be obtained even in a product such as a conductive brush. This is because the conductive layer matrix polymer used in the conventional polyester conductive yarn has a low affinity for carbon black, so the dispersibility of carbon black is poor, and carbon black is localized at a high concentration. This is because the deformation becomes poor and the stretching becomes non-uniform (stretching spots and heat treatment spots are large), resulting in crimped spots. On the other hand, by using the PPT of the present invention, as described above, since the affinity with carbon black is high, the stretchability is dramatically improved. Furthermore, since the conductive layer and the non-conductive layer form a side-by-side composite or an eccentric core-sheath composite, the fiber of the present invention can potentially cause crimping without applying false twisting, and a brush By applying a heat treatment after the formation, a crimped yarn having high quality and excellent covering properties can be obtained.

  The conductive yarn of the present invention has high-quality and fine coil crimps, and can suppress the association between yarns. When used as a conductive brush, the conductive yarn has high uniformity due to excellent covering performance. It is possible to exhibit static elimination performance and toner cleaning properties. Furthermore, since the apparent elastic modulus can be greatly reduced by using the coil crimped yarn, the photoreceptor is not damaged. In addition, since there are more trap spots for holding toner than non-crimped yarns, it is possible to suppress a decrease in toner cleaning performance on the photoreceptor during long-time running.

  The crimped yarn of the present invention has the ability to develop coil crimp by heat treatment or to produce finer coil crimp than before heat treatment, and is distinguished from ordinary false twisted yarn. is there. That is, the conductive yarn of the present invention can be made into a latent crimp-expressing polyester by performing a normal drawing process, and as described above, by drawing at 0.9 to 1.3 times NDR. The residual elongation is 20 to 50%. In general, the smaller the residual elongation, the smaller the coil diameter when the crimp is made apparent, and the number of coils per unit fiber length increases, but the structural elastic recovery tends to decrease. On the other hand, when the residual elongation is less than 20%, troubles such as fuzz and yarn breakage in the stretching process tend to increase. On the other hand, when the residual elongation exceeds 50%, the coil diameter when the crimp is made apparent is increased, the number of coils per unit fiber length is decreased, and the crimp characteristics are deteriorated.

  Moreover, when the fiber of this invention is an eccentric core-sheath composite, the magnitude | size of the crimp expressed also by eccentricity is controllable. Here, the eccentricity will be described in detail with reference to FIG. FIG. 1 shows an example of a cross section of an eccentric core-sheath type composite fiber of the present invention, wherein the sheath part is A and the core part is B. The center of gravity obtained from the cross section of the entire conjugate fiber is a, and the center of gravity obtained from the cross section of only the core is b. Here, as a premise for obtaining the center of gravity, there is no difference in density between the core and the sheath. Further, the eccentricity is obtained from the distance between the centers of gravity and the diameter D of the composite fiber by the following equation.

Eccentricity = (Distance between centroid a and centroid b) / (1/2 × D)
In the case of the eccentric core-sheath composite fiber, the greater the degree of eccentricity, the smaller the coil diameter, and the number of coils per unit fiber length increases, but the structural elastic recovery tends to decrease. On the other hand, if the degree of eccentricity is small, the coil diameter increases, the number of coils per unit fiber length decreases, and the crimp characteristics deteriorate. Therefore, the eccentricity is preferably 0.04 to 0.6. More preferably, it is 0.1-0.5, More preferably, it is 0.15-0.45.

  Although the characteristics of crimped yarn can be expressed by a number of indices, our study has determined that the CR value is the most preferable index in terms of the correlation with the printing characteristics of the conductive brush. It is important that the conductive yarn of the present invention has a crimp that does not allow the yarn to be entangled, and the CR value is preferably 3% or more. On the other hand, if the CR value exceeds 50%, the coil diameter becomes too small and the trap spot becomes small, so that the cleaning property is lowered or the high-order workability when making a conductive brush is lowered. Therefore, the CR value is preferably 3 to 50%. More preferably, it is 10-40%, More preferably, it is 15-30%. The CR value is an index representing the crimp extension / recovery characteristic.

  The conductive yarn of the present invention preferably has a boiling water shrinkage of 0 to 15%. When used as a conductive brush, it may be exposed to high temperatures depending on the brushing process and the environment during use, and it is necessary to minimize the dimensional change before and after processing. Further, it has been found that if the conductive yarn has a dimensional change, the carbon structure inside the fiber also changes and the conductive performance changes. In order to provide a conductive yarn having excellent stability against environmental changes, the boiling water shrinkage is more preferably 0 to 10%, and further preferably 0 to 6%. Examples of means for reducing the shrinkage rate include a heat treatment temperature during stretching, a draw ratio, a relaxation rate, and the like.

  The conductive yarn of the present invention preferably has a volume resistivity ratio before and after heat shrinkage of 100 or less. In general, a conductive brush of an image forming apparatus is woven as a pile of conductive yarn, and then spirally wound around a cylindrical surface to form a brush. However, in order to prepare the pile, heat setting is performed by hot water treatment. Further, when used in an image forming apparatus, the usage environment is severe and a large temperature and humidity change occurs. Therefore, it is preferable that the ratio of the volume resistivity before and after heat shrinkage is smaller because the volume resistivity is more stable with respect to changes in temperature and humidity during the heat treatment process or for a long time use. If the ratio of the volume resistivity before and after the heat treatment exceeds 100, the volume resistivity decreases while the conductive brush is used, and at the same time, the volume resistivity varies between the fibers constituting the brush, and the image The sharpness of the image is reduced. The ratio of the volume resistivity before and after the heat treatment is more preferably 10 or less, and further preferably 5 or less.

  When the composite form is a side-by-side composite, in order to improve the contact efficiency between the conductive layer and the charged material, the ratio of the exposed length of the conductive layer to the circumferential length in the fiber cross section is 50% or more. And the conductive layer is preferably outside the coil crimp. That is, a polyester having a thermal contraction rate lower than that of the polyester forming the nonconductive layer is selected as the matrix polymer for the conductive layer. On the other hand, the fiber-forming polyester, which is a non-conductive layer, plays a complementary role in improving spinning and drawing properties and enhancing the mechanical properties of the fiber. Furthermore, in order to impart a crimp to the fiber using a shrinkage difference from the conductive layer, the ratio of the non-conductive layer is preferably at least 20% or more. That is, the ratio of the exposed length of the conductive layer to the peripheral length in the fiber cross section is preferably 50 to 80%.

  When the composite form is an eccentric core-sheath composite, high conductivity can be imparted in the fiber longitudinal direction by adopting an eccentric core-sheath composite structure in which the nonconductive layer is the core. By exposing the conductive layer to the entire fiber surface, printing spots are suppressed when used as a conductive brush, and high-quality printing characteristics can be obtained.

Moreover, it is preferable that the core part which is a nonelectroconductive layer of an eccentric core-sheath composite fiber occupies 60% or less of fiber cross-sectional area. The fiber-forming polyester, which is a non-conductive layer, plays a complementary role in improving spinning and drawing properties and enhancing the mechanical properties of the fiber. Furthermore, the core is preferably 20% or more of the cross-sectional area of the fiber in order to impart a crimp to the fiber by utilizing the difference in contraction with the sheath, and 60 % or less in order to impart high conductivity. It is preferable that More preferably, it is 40 to 60%.

  The outer peripheral shape of the fiber of the present invention may be a round cross section, a triangular cross section, a multi-lobe cross section, a flat cross section, a hollow cross section, or other known irregular cross sections, and is limited as long as it does not impair the spirit of the invention. is not. Since it imparts high conductivity and crimp development in the longitudinal direction of the yarn, the eccentric core-sheath type (a), (b), (f), circular side-by-side type (c) to (e) as shown in FIG. The cross-sectional shapes of hollow side-by-side type (g), flat side-by-side type (h), (i), and triangular side-by-side type (j) are preferably used.

  The fibers in the present invention may be long fibers (filaments) or short fibers (staples). In the case of short fibers, the length may be set to a desired length depending on the application, but when used for a spinning process or electric flocking, the length is preferably 0.05 to 150 mm, preferably 0.1 to 120 mm. It is more preferable that

  The thickness of the fiber of the present invention, that is, the single fiber diameter is not particularly limited, but the single fiber diameter may be 50 μm or less in that it can be used for various applications as described later. Preferably, it is 5-30 micrometers. In particular, when used in a conductive brush of an image forming apparatus, the fiber diameter is particularly preferably 5 to 25 μm from the viewpoint of excellent cleaning performance or charging performance. In the case of being used for clothing lining, dust-proof clothing, or other various clothing, the thickness is preferably 5 to 30 μm. Moreover, when used for non-clothing applications such as interior materials such as vehicle interior materials and building wall materials, carpets, flooring materials, etc., other than clothing applications, the thickness is preferably 10 to 50 μm.

  In the range of the volume resistivity, not only the conductive brush of the image forming apparatus but also various uses, for example, clothes such as stockings, tights, and dust-proof clothing as antistatic materials, or carpets and mats laid indoors and outdoors and in vehicles. It can be developed in various products such as flooring, and can impart desired conductivity.

The flocked body using at least a part of the short fibers made of the conductive yarn of the present invention can be formed and used in a fiber brush using at least a part. In particular, a fiber brush roller directly planted on a rod-like object is preferable. The short fiber used here may be sprayed with a gas when it is implanted in a rod-like object, or may be subjected to electric flocking, but it is efficient that it is generally upright on the surface of the rod-like object. Since it can be obtained well, it is preferably obtained by electric flocking. At this time, 50% or more of the short fibers are bonded in a generally upright state from 10 degrees to the vertical (that is, 90 degrees) on the surface of the rod-like object. Here, as long as the spirit of the invention is not impaired, the short fibers used are not only the short fibers made of the conductive yarn of the present invention but also the short fibers made of other fibers that are not the conductive yarn of the present invention. May be. In addition, the adhesive for planting by adhesion is not particularly limited, and for example, an acrylic, urethane, or ester adhesive is selected and used depending on the application or purpose. The thickness of the agent layer is preferably 1 to 500 μm, and a single layer or, if necessary, a plurality of types of adhesives may be mixed or divided into a plurality of layers. Moreover, the volume specific resistance of the fiber brush roller itself of the said polyester fiber brush roller formed by using the short fiber which consists of the polyester fiber of this invention for at least one part and sticking to a rod-shaped object is 10 < ^-1 > -10 < ⁷ > ohm * cm. Preferably there is.

  The main material used for the core of the rod-shaped object described above may be any material suitable for the intended use or purpose, and may be selected from metals, synthetic resins, natural resins, wood, minerals, etc., alone or in combination. However, when used as a member to be incorporated in an image forming apparatus described later, it is preferably made mainly of metal. Further, when the rod-shaped object is a metal, an intermediate layer covers the entire surface of at least a part of the metal or a necessary part, and the woven fabric and / or knitted fabric and / or the nonwoven fabric is adhered thereon, Or it is preferable that a short fiber adheres and is planted. The material used as the intermediate layer mainly provides cushioning properties to the rod-like object, or bears auxiliary elasticity / rigidity when it cannot be achieved only by the elasticity / rigidity of the brush-like fibers, which will be described later. For example, the toner cleaning performance in the cleaning device or the toner application performance in the developing device is significantly improved. Although not particularly limited, for example, a urethane material, an elastomer material, a rubber material, or an ethylene-vinyl alcohol material is preferably used for the intermediate layer. And it is preferable that the thickness of this intermediate | middle layer is 0.05-10 mm, Furthermore, the above-mentioned electroconductivity control agent or magnetic control agent may be added as needed.

  The above-mentioned woven fabric, knitted fabric or non-woven fabric using at least a part of the conductive yarn of the present invention can be bonded to a base to form a fabric composite. In this case, if the fabric is pile weave or yarn ends on the surface of the fabric by pile weaving or treatment, and if the knitted fabric is pile-like fiber raising or raising the pile or yarn ends are on the knitted surface In the polyester fiber brush roller described later, the function may be further enhanced, which is preferable. When bonding and forming at the time of joining, it is preferred to adhere using, for example, an acrylic, urethane, or ester adhesive. Here, the thickness of the adhesive layer is preferably 1 to 500 μm, and a single layer or, if necessary, a plurality of types of adhesives may be mixed or divided into a plurality of layers.

  Further, the substrate to be bonded is not particularly limited, and may be appropriately selected according to the apparatus incorporating the fabric composite and the adhesive used. However, synthetic resin, natural resin, synthetic fiber, natural fiber, wood Films, sheets, paper, boards, or other fabrics made of minerals or metals can be suitably used, or directly on the base of metal processed bodies, synthetic or natural resin processed bodies or molded bodies that are members for various uses. It may be glued. In particular, in order to increase the affinity with the adhesive, a sheet made of a synthetic or natural resin or metal subjected to a hydrophilic treatment is preferable. If the substrate is a material forming the front and back surfaces, such as the film, sheet, paper, board, or fabric, the fabric is formed by adhering the woven fabric, knitted fabric, or nonwoven fabric to both the front and back surfaces according to the purpose or purpose. Can be a composite. The fabric composite may be used by being attached to another substrate as its usage or application, or may be used as a conductive polyester fiber brush because it has the following conductivity, for example.

  The woven fabric and / or knitted fabric and / or non-woven fabric made of the polyester fiber of the present invention can be used at least in part or in all to form a polyester fiber brush. In particular, it is preferable to use a woven fabric in terms of stable form. The woven fabric and / or knitted fabric and / or non-woven fabric used here is the functionally required length (i.e., winding width) of the rod-shaped object when bonded to the rod-shaped object to form a polyester fiber brush roller. The cut material may be wound and joined in one round, or the material cut into a slit with a width that is a fraction of one-tenth of the length of the rod-like object is wound around the rod-like object in a spiral shape May be joined. When joining, it may fit by attaching unevenness to the rod-shaped substance in advance, but it is preferable to bond using an adhesive in terms of reliable joining.

The adhesive used here may be appropriately employed depending on the application or purpose, and various adhesives such as acrylic, ester or urethane can be employed, and the conductivity control of carbon black, metal, etc., if necessary. An agent or a magnetic control agent such as a metal such as iron, nickel, cobalt, and molybdenum, an oxide of these metals, or a mixture thereof may be added. Here, the thickness of the adhesive layer is preferably 1 to 500 μm, and a single layer or, if necessary, a plurality of types of adhesives may be mixed or divided into a plurality of layers. Furthermore, a material such as a conductive treatment agent or a conductive sheet or a conductive film having a volume resistivity of 10 ⁻¹ to 10 ⁷ Ω · cm on the bonding surface before the woven fabric and / or knitted fabric and / or non-woven fabric is bonded. May be pasted together.

  The conductive yarn of the present invention is, for example, a fabric such as a woven fabric, a knitted fabric, or a non-woven fabric, a fiber brush using the same, clothing, a rug, a flocked body using short fibers, or a wiring object capable of flowing electricity. , Etc., a polyester fiber product used at least in part can be obtained.

  The conductive yarn of the present invention is an aggregate of fibers having a coil crimp. This coil crimp repeats “association” and “non-association” between single fibers. Conductive spots may occur at the meeting part and the non-association part in the longitudinal direction of the yarn. It has been found that it is effective to give an appropriate twist as a means for avoiding this. The twist coefficient K is preferably adjusted appropriately according to the CR value. When the CR value is low, the twist coefficient is preferably low, and when the CR value is high, the twist coefficient is preferably high. The twist coefficient K is preferably in the range of 400 to 20,000. For example, when the CR value is 3 to 10, the twist coefficient is preferably in the range of 400 to 2,000, and when the CR value is 10 to 30, 1,000. When the CR value exceeds 30, it is preferably 5,000 to 20,000.

However, twist coefficient K = T × D ^0.5
T: number of twists per 1 m of yarn length, D: fineness of yarn (dtex)
Here, the number T of twists per 1 m of yarn length is after untwisting the untwisted number when untwisted under a load of 90 × 10 ⁻³ cN / dtex with an electric tester and completely untwisted. The value divided by the yarn length.

A. Melt viscosity Using Capillograph 1B manufactured by Toyo Seiki Co., Ltd., under a nitrogen atmosphere, with a barrel diameter of 9.55 mm, a nozzle length of 10 mm, and a nozzle inner diameter of 1 mm, a polymer extrusion piston speed of 1 mm / min (shear speed of 12.16 (1 / second) )), And measured after 10 minutes from immediately after sample filling. The average value of the values measured five times was taken as the melt viscosity at each shear rate.
B. Melting | fusing point The peak temperature of crystal melting was measured as melting | fusing point by 2nd run using DSC-7 made from Perkin elmer. At this time, the sample weight was about 10 mg, and the heating rate was 10 ° C./min. In the case of a fiber in which a conductive layer and a non-conductive layer are combined, it is necessary to separate the respective layers. When measuring the melting point of the non-conductive layer, only the non-conductive layer can be taken out by removing the conductive layer by surface etching (for example, dissolution with an alkali solution) of the fiber. Moreover, when measuring melting | fusing point of a conductive layer, only a conductive layer of a fiber surface layer can be melt | dissolved using OCP, and only a conductive layer can be taken out by volatilizing the dissolved OCP solution.
C. Fineness and single fiber fineness Take a thread of 100 m in length and multiply the weight (g) of the crushed sample by 100 to obtain. The average value of the values measured three times was defined as the fineness (dtex) of the yarn, and the value obtained by dividing the fineness by the number of constituent filaments was defined as the single fiber fineness (dtex).
D. Strength, Residual elongation, Initial tensile resistance According to JIS L1013 (1992) "Chemical fiber filament yarn test method", using Tensilon tensile tester (TENSILON UCT-100) manufactured by Orientec, if undrawn yarn A load-elongation curve (hereinafter referred to as “SS curve”) was obtained at an initial sample length of 50 mm, a tensile speed of 400 mm / min, and a crimped yarn at an initial sample length of 200 mm and a tensile speed of 200 mm / min. The value obtained by dividing the maximum point tension of the SS curve by the fineness is the strength, and the value obtained by dividing the elongation when the maximum point tension is shown by the initial sample length is the residual elongation. Value. The initial tensile resistance was recorded as an initial sample length of 200 mm, a tensile speed of 200 mm / min, a chart speed of 100 cm / min, and a stress full range of 500 g, and was determined from the maximum slope of the initial tensile curve.
E. Constant tension elongation region elongation From the SS curve obtained by the measurement of the undrawn yarn of the above E term, as shown in FIG. 3, the necking is formed from the origin (point a) (point b) and stretched at a constant tension. Is completed (point c). The value obtained by dividing the elongation up to the point c by the initial sample length was defined as the constant tension elongation region elongation (%).
F. Volume resistivity P, ratio of volume resistivity P to standard deviation Q ESR (ESR = Q / P)
A sample held at medium temperature and medium humidity (25 ° C, humidity 65% RH) for at least 1 hour is connected to an insulation resistance meter SM-8220 made by Toa DKK between a pair of mirror rollers consisting of a yarn feeding roller and a winding roller. It is made to run so that it may touch the probe which consists of two bar terminals. With an insulation resistance meter, the rod terminal has a thickness of 2 mm, a measurement distance of 2.0 cm, an applied voltage of 100 V, a yarn feeding speed of 60 cm / min, and a yarn tension between rollers of 0.05 to 0.1 cN / dtex. The length of 120 cm was measured at a sampling rate of 5 Hz, and the average resistance value (Ω) of the obtained value (600 points) divided by the distance (2.0 cm) of the thread contacting the bar terminals was the average resistance. The volume specific resistance P (Ω · cm) was obtained by multiplying the value by the yarn cross-sectional area (cm ² ). Moreover, the standard deviation Q of all the volume specific resistances (600 points) obtained at the same time was obtained, and the ratio ESR (ESR = Q / P) of P and Q was calculated. The volume resistivity P ′ after shrinkage was determined by measuring the sample after treating it in a dry heat 150 ° C. oven for 5 minutes.

In the case of a gut-shaped one, the two terminals were pressed against the gut at an interval of 10 cm using a tester, the resistance value R (Ω) was measured, and the volume specific resistance P was obtained by the following equation. The volume resistivity was obtained for five different guts, and the average value was taken as the volume resistivity P of the gut.
Volume resistivity P (Ω · cm) = R × (D / 2) ² × π / 10
G. Weight average molecular weight, number average molecular weight The weight average molecular weight Mw and the number average molecular weight Mn were measured by GPC (gel permeation chromatography) using GPC-244 manufactured by WATERS. The measurement conditions were as follows: Shodex HFIP 806M (inner diameter 8.0 mm / length 30 cm, two columns) as a column, hexafluoroisopropanol as a solvent, temperature 23 ° C., flow rate 0.5 ml / min. A calibration curve was prepared and measured using PMMA (polymethylmethacrylate) manufactured by Polymer Laboratory as a standard sample. Further, the degree of dispersion Mw / Mn was determined. In addition, when measuring the average molecular weight Mw and Mn of the polymer in a conductive layer, it is necessary to isolate | separate carbon black and a polymer previously. In that case, the sample of the conductive layer is once dissolved in orthochlorophenol (hereinafter referred to as OCP. The dissolution temperature is from room temperature to 160 ° C. depending on the dissolved state), and is centrifuged (usually 6,000 to 30,000 rpm). After removing the carbon black, the sample can be obtained by volatilizing the OCP.
H. Boiling water shrinkage rate Using a scale, the initial load: (0.088 × fineness (dtex)) cN, a casserole length of 50 cm and a wrapping number of 10 turns, a sample length L1 with a specified load applied Measure. This was treated in boiling water for 15 minutes in a substantially load-free state, air-dried for one day and night, the bundle length L2 was measured, and the boiling water shrinkage rate was calculated by the following equation. In addition, what was calculated | required by the following formula was used for the load.

Boiling water shrinkage rate (%) = ((L1-L2) / L1) × 100
Load (cN) = (Fineness (dtex) /1.111) × 0.1 × 0.9807 × Number of windings × 2
I. CR value A crimped yarn was cut with a sash length of 50 cm and a winding number of 10 times, treated in boiling water for 15 minutes in a substantially load-free state, and air-dried for 24 hours. The sample was immersed in water under a load equivalent to 0.088 cN / dtex (0.1 gf / d), and the skein length L3 after 2 minutes was measured. Next, the skein length L4 after 2 minutes was measured after exchanging with a fine load equivalent to 0.0018 cN / dtex (2 mgf / d) except in water for the case corresponding to 0.088 cN / dtex. And CR value was calculated by the following formula.

CR (%) = [(L3-L4) / L3] × 100 (%)
J. et al. Average particle diameter of carbon black A block in which fibers or a resin are embedded in an epoxy resin is dyed with a ruthenium oxide solution and cut with an ultramicrotome to produce an ultrathin section having a thickness of 60 nm to 100 nm. This sample was observed with a transmission electron microscope (TEM) observation apparatus (H-7100FA type manufactured by Hitachi, Ltd.) at an acceleration voltage of 75 kV and an arbitrary magnification of 20,000 to 100,000 times, and the resulting photograph was black and white Digitized. The average particle size was confirmed by image analysis of carbon black that appeared black in WinROOF (version 2.3) manufactured by Mitani Corporation of computer software. The average particle diameter was calculated from the average value of the diameters of carbon blacks calculated by calculating the area of all the carbon blacks present on the photograph and judging from the area values to be substantially circular.
K. Measurement of Dibutyl Phthalate Absorption A measurement was performed using an absorber in accordance with “How to Obtain DBP Absorption” of JIS K6217-4: 2001.
L. Composite ratio, ratio of the exposed length of the conductive layer to the circumference in the fiber cross section, eccentricity Fabricate a block in which the fiber is embedded in epoxy resin, and cut it in the fiber cross section direction perpendicular to the fiber axis direction with a microtome. And make a thin slice. This is observed and photographed with transmitted light with an optical microscope 200 times, and the obtained fiber cross-sectional photograph is subjected to image analysis with the above-mentioned WinROOF manufactured by Mitani Corporation, so that the composite ratio is a conductive layer and a non-conductive layer. The ratio was calculated from the area. The ratio of the exposed length of the conductive layer to the peripheral length in the fiber cross section was calculated by measuring the peripheral length in the fiber cross section and the exposed length of the conductive layer. In addition, the eccentricity of the eccentric core-sheath composite cross section is calculated based on the center of gravity a obtained from the cross section of the entire composite fiber as shown in FIG. 1, the center of gravity b obtained from the cross section of the core only, and the fiber diameter D by WinROOF manufactured by Mitani Corporation. The degree of eccentricity was calculated by the following formula. As a premise for obtaining the center of gravity, there is no difference in density between the core and the sheath.

Eccentricity = (Distance between centroid a and centroid b) / (1/2 × D)
M.M. Measurement of single fiber diameter After performing a platinum-palladium vapor deposition (deposition film pressure: 25 to 50 angstrom) at an acceleration voltage of 2 kV using a scanning electron microscope (SEM) STRATA DB235 manufactured by FEI Company, the outer diameter of the fiber Are within the field of view (5,000 times if the single fiber diameter is 25 μm to 50 μm, 10,000 times if the single fiber diameter is 15 μm to 25 μm, and 20,000 times if it is 5 μm to 15 μm). At this time, the single fiber diameter is defined as an average value obtained by observing and measuring at least five points at an interval of 3 cm or more in the same fiber. N. Image Evaluation Method Conductive yarn was brushed and printed continuously for a long time with a monochrome laser printer installed in a cleaning device. Evaluation of images at the initial stage and after printing 20,000 sheets was performed according to the following criteria.
(1) Initial performance evaluation A: A clear and uniform image is obtained.

  ○: Abnormal discharge trace is not recognized, but the image is slightly unclear.

  Δ: Some abnormal discharge traces are observed.

X: The image is unclear and streaks are conspicuous.
(2) Repeated (20,000 sheets) image evaluation A: A clear and uniform image similar to the initial one can be obtained.

  ○: Abnormal discharge trace is not recognized, but the image is slightly unclear.

  Δ: Some abnormal discharge traces are observed.

  X: The image is unclear and streaks are conspicuous.

Example 1
PPT pellets having a weight average molecular weight of 83,000, a dispersity of Mw / Mn of 3.4, and a melting point (Tm) of 229 ° C. were vacuum-dried at 150 ° C. for 10 hours, and then powdered in a nitrogen atmosphere to form carbon black as a furnace black manufactured by Degussa ( type L, an average particle diameter of 23 nm, was dibutyl phthalate absorption 116cm ³ / 100g, the following as "FCB") was mixed powders each other under a nitrogen atmosphere. Subsequently, with a twin-screw extruder TEM35B (shaft length L: 1440 mm, shaft diameter D: 37 mm, L / D: 38.9) manufactured by Toshiba Machine Co., Ltd., shaft rotation speed: 300 rpm, kneading temperature C1-C4 and H: 250 Melting and kneading were performed at a temperature of C, discharge rate: 15 kg / hr, and vent: about 5 Torr. Here, the concentration of FCB was adjusted to be 25% by weight with respect to the PPT / FCB kneaded product obtained after completion of kneading. After kneading, the discharged gut-shaped resin composition was cooled with tap water at 15 ° C. and then cut with a cutter to obtain a conductive layer pellet (hereinafter referred to as “PPT-CB”). When the melt viscosity of the pellet was measured, it was 2010 (Pa · sec) (measuring temperature 260 ° C., 12.16 (1 / sec)). When the specific resistance value of the gut before pelletizing was measured, it was 10 ^1.4 Ω · cm.

  Polyethylene terephthalate obtained by copolymerizing 7 mol% of IPA and 4 mol% of BPA-EO using the PPT-CB (melting point: 228 ° C.) as a sheath (component B) (denoted as “copolymerized PET” in the table) (melting point) 228 ° C.) as the core (component A), charged into the component A hopper 1 and component B hopper 1 ′ attached to the spinning machine shown in FIG. 4, respectively, melted separately in the extrusion kneaders 2 and 2 ′, and the metering pump 3. Weighed at 3 and led to the spinning pack 5, using a base 6 (discharge hole diameter 0.5 mm / hole depth 1.0 mm) at a spinning block 4 temperature of 260 ° C., core-sheath composite ratio (core / sheath weight%) 50/50 was discharged. The discharged yarn 8 is cooled and solidified by a cooling device 7 with a cooling air of 0.4 m / second, and an oil agent is applied while being focused by an oil supply guide 9 at a position 2 m below the base, and a peripheral speed is 1500 m / min. Taking up with the first godet rollers 10 and 11, the take-up yarn package 13 was obtained by winding 2 kg of undrawn yarn of an eccentric core-sheath composite structure of 485 dtex and 54 filaments with a winder 12. The surface pressure during winding was 10 kg / m, and the twill angle was 5 °. In addition, as a smoothing agent for spinning oil, 70% by weight of polyether having a weight average molecular weight of 2000, 8% by weight of polyether having a weight average molecular weight of 6000, 12% by weight of ether ester, and other additives (antistatic agent, antioxidant) Agent and rust preventive agent) were adjusted to 10% by weight, and this oil was adjusted as a water emulsion to a concentration of 10% by weight, and about 1.5% by weight was adhered to the fiber as a pure oil. The spinnability was good, and no yarn breakage occurred when sampling 40 kg of undrawn yarn.

  Further, the unstretched yarn is fed using a four-roller type stretching machine of a supply roller, a first hot roller, a second hot roller, and a draw roller, a first hot roller temperature of 80 ° C., a second hot roller temperature of 140 ° C., a supply roller and a first roller The magnification between the 1st hot roller is 1.005 times, the magnification between the 1st hot roller and the 2nd hot roller is 2.2 times (NDR × 1.05), the magnification between the 2nd hot roller and the draw roller is 1.0 times Stretched. The drawing speed (peripheral speed of the draw roller) was 500 m / min, and a conductive yarn package having a fineness of 220 dtex and 54 filaments was obtained. The yarn threading property and process passability were good, and yarn breakage did not occur. In addition, the expansion / contraction recovery rate (CR value) indicating the crimp characteristics of the obtained yarn was 23%, and a conductive yarn having good mechanical characteristics and crimp characteristics was obtained. The fiber cross section was as shown in FIG. 2 (a), and the eccentricity was 0.3.

The strength of the conductive yarn obtained in Example 1 was 2.4 cN / dtex, the residual elongation was 35%, the initial tensile resistance was 55 cN / dtex, the boiling water shrinkage was 4.8%, and the volume resistivity was 2.7 × 10 ^1. The Ω · cm and the ESR value were 0.03.

  After the conductive yarn was twisted at 100 T / m (twisting coefficient: 1483), a pile woven fabric was produced, the pile was raised, and a 1 cm wide slit was wound around a metal rod-like object made of SUS304. A brush roller was obtained. When the obtained brush roller was installed in a cleaning device and placed in a monochrome laser printer, continuous printing was performed for a long time (10 sheets printed / discharged per minute), and the printability was confirmed along with the humidity change in the printer. The humidity in the printer dropped from the initial 67% to 34% when printing started about 1000 sheets, and further decreased to 26% when printing about 10,000 sheets. The brush of Example 1 was excellent in the sharpness of printing and the toner cleaning performance from the initial printing up to 20,000 sheets even in the change of the humidity environment.

Example 2 and Reference Example 3
The conductive yarns of Example 2 and Reference Example 3 were obtained in the same manner as in Example 1 except that the carbon black content was 17% by weight and 37% by weight. The volume resistivity of Example 2 was 1.2 × 10 ⁷ Ω · cm, and the static elimination performance was slightly inferior to that of Example 1, but the sharpness of printing from the initial printing to 20,000 sheets, toner The cleanability did not change, and there was no problem in practical use. The specific volume resistance of Reference Example 3 was 3.4 × 10 ⁰ Ω · cm, indicating high electrical conductivity, but the spinnability was slightly reduced due to the high carbon black content. The ESR value was 0.32, and the conductive spots in the yarn longitudinal direction were higher than in Example 1. Further, the strength of the conductive yarn was as low as 0.9 cN / dtex, the durability was lower than that of Example 1, and the toner cleaning property was slightly lowered with the number of printings.

Comparative Example 1 and Comparative Example 2
A conductive yarn of Comparative Example 1 and Comparative Example 2 was obtained in the same manner as in Example 1 except that the carbon black content was 12% by weight and 45% by weight. The volume resistivity of Comparative Example 1 was 2.1 × 10 ⁹ Ω · cm, and the volume resistivity was too high, so that the charge removal performance could not be obtained. In Comparative Example 2, the spinnability was poor because the carbon black content was large, and yarn breakage occurred frequently during spinning, and could not be taken up.

Reference Examples 4-7
Evaluation was performed in the same manner as in Example 1 except that PBT having a weight average molecular weight Mw of 55,000, 90,000, 130,000, and 350,000 was used as the matrix polymer of the conductive layer. In Reference Example 4, the spinnability was slightly reduced and the ESR value was 0.09, and the conductive spots in the longitudinal direction of the yarn were slightly higher than those in Example 1, but the level was not problematic in practice. The volume resistivity was 5.6 × 10 ¹ Ω · cm and the static elimination performance at the initial stage of printing was good, but the strength of the conductive yarn was slightly low at 1.9 cN / dtex, which was more durable than Example 1. The toner cleaning performance decreased slightly with the number of printings. The volume resistivity of Reference Example 5 is 1.5 × 10 ² Ω · cm, the ESR value is 0.04, and the CR value is 16%. Like Example 1, it has excellent static elimination performance and is 20,000 from the initial printing stage. The sharpness of printing up to the sheet and the toner cleaning ability were excellent. The volume specific resistance of Reference Example 6 is 5.2 × 10 ² Ω · cm, the ESR value is 0.04, and the CR value is 14%. The sharpness of printing and the toner cleaning properties are not changed from the initial printing to 20,000 sheets. The static elimination performance was good. The volume resistivity of Reference Example 7 was 9.4 × 10 ² Ω · cm, the ESR value was 0.08, and the initial static elimination performance was good, but the CR value was 10%, which is slightly higher than that of Example 1. The toner is low and has a low crimping property, and the toner cleaning performance is slightly lowered with the number of printings.

Reference Example 8
Evaluation was made in the same manner as in Example 1 except that PBT having a weight average molecular weight Mw of 480,000 was used as the matrix polymer of the conductive layer and the draw ratio was 2.1 times (NDR × 1.00). The volume resistivity of Reference Example 8 was 7.8 × 10 ² Ω · cm, the ESR value was 0.11, and the CR value was 9%. There was no level.

Reference Example 9
Evaluation was performed in the same manner as in Example 1 except that PBT having a weight average molecular weight Mw of 600,000 was used as the matrix polymer of the conductive layer, and the draw ratio was 1.9 times (NDR × 0.90). The volume resistivity of Reference Example 9 is 4.3 × 10 ² Ω · cm, the ESR value is 0.19, and the CR value is 7%, and the static elimination performance is inferior to that of Example 1, but this is a practical problem. There was no level.

Reference Example 10
Evaluation was performed in the same manner as in Example 1 except that polyethylene terephthalate (described as “PET” in the table) (melting point: 255 ° C.) was used as the fiber-forming polyester of the non-conductive layer and the spinning temperature was 285 ° C. did. In Reference Example 10, the spinnability decreased and the yarn breakage was slightly more than in Example 1. The obtained conductive yarn had an ESR value of 0.35, and some abnormal discharge traces were observed.

Comparative Example 3
Polyethylene terephthalate copolymerized with 10 mol% of IPA (described in the table as “copolymerized PET”) (melting point: 227 ° C.) as the matrix polymer of the conductive layer, and polyethylene terephthalate (described as “PET” in the table) as the non-conductive layer ) (Melting point: 255 ° C.), and evaluation was performed in the same manner as in Example 1 except that the spinning temperature was 285 ° C. In Comparative Example 3, the spinnability was low, and yarn breakage occurred frequently during spinning. The ESR value indicating the variation in conductivity was 0.60. Along with this, the image was unclear and streaks were conspicuous.

Example 11
The same as in Example 1 except that polyethylene terephthalate copolymerized with 5 mol% of adipic acid (described in the table as “copolymerized PET”) (melting point 243 ° C.) was used as the fiber-forming polyester of the non-conductive layer. The method was evaluated. In the conductive yarn of Example 11, the non-conductive layer forms the outer side of the coil crimp, the volume resistivity is 4.6 × 10 ² Ω · cm, and the ESR value is 0.12. The static elimination performance was slightly inferior, but the crimp fastness was excellent, and the sharpness of printing and toner cleaning performance were good from the initial printing to 20,000 sheets.

Reference Example 12 and Example 13
The conductive yarns of Reference Example 12 and Example 13 were obtained in the same manner as in Example 1 except that the core / sheath composite ratio was set to 10/90 and 30/70. In Reference Example 12, since the ratio of the non-conductive layer responsible for the fiber forming performance was 10%, the spinnability was slightly lowered, and the ESR value was 0.31. Further, although the CR value was 8% and the strength was 1.6 cN / dtex and the initial static elimination performance was excellent, the durability was lower than that of Example 1, and the toner cleaning performance was slightly lowered with the number of printings. The volume resistivity of Example 13 is 1.9 × 10 ¹ Ω · cm, the ESR value is 0.05, and the CR value is 17%. Like Example 1, it has excellent static elimination performance and is 20,000 from the initial printing stage. The sharpness of printing up to the sheet and the toner cleaning ability were excellent.

Reference Example 14 and Reference Example 15
The conductive yarns of Reference Example 14 and Reference Example 15 were obtained by evaluating in the same manner as in Example 1 except that the core-sheath composite ratio was 70/30 and 90/10, and the eccentricity was changed by changing the composite base. It was. The cross section of the fiber was as shown in FIG. 2 (b), and the eccentricity was 0.15. The volume specific resistance of Reference Example 14 is 3.2 × 10 ² Ω · cm, the ESR value is 0.07, and the CR value is 25%. The sharpness of printing and the toner cleaning property are not changed from the initial printing to 20,000 sheets. The static elimination performance was good. In Reference Example 15, since the ratio of the conductive layer responsible for the conductive performance is 10%, the volume resistivity is 4.1 × 10 ³ Ω · cm, the ESR value is 0.15, which is slightly higher than that of Example 1, and the static elimination performance. Although it was slightly inferior, it was a level which is satisfactory practically.

Reference Example 16 , Examples 17, 18 and Reference Example 19
Example 1 except that the composite ratio (non-conductive layer / conductive layer weight%) was 12/88, 25/75, 50/50, 70/30, and the composite base was changed to a side-by-side type. The conductive yarns of Reference Examples 15 and 16, and Examples 17 and 18 were obtained by evaluation by the method. The ratio of the exposed length of the conductive layer of Reference Example 16 is 85%, the cross section of Example 17 is FIG. 2 (c), the ratio of the exposed length of the conductive layer is 70%, and the cross section of Example 18 is FIG. The ratio of the exposed length of the conductive layer was 45%, the cross section of Reference Example 19 was as shown in FIG. 2 (e), and the ratio of the exposed length of the conductive layer was 35%.

In Reference Example 16, the ratio of the non-conductive layer responsible for the fiber forming performance was 12%, so that the spinnability was slightly lowered and the ESR value was 0.33. Further, the strength was 1.7 cN / dtex, and although the initial static elimination performance was excellent, the durability was lower than that of Example 1, and the toner cleaning property was slightly lowered with the number of printings. The volume resistivity of Example 17 was 7.6 × 10 ¹ Ω · cm, the ESR value was 0.08, and the CR value was 22%, which was slightly inferior to Example 1, but 20,000 from the initial printing stage. The clearness of printing up to the sheet and the toner cleaning property were not changed and were practically satisfactory. The volume resistivity of Example 18 is 1.4 × 10 ² Ω · cm, the ESR value is 0.10, and the CR value is 38%. Although slightly inferior to Example 1, printing from the initial printing to 20,000 sheets is clear. The neutralization performance and toner cleaning performance were not changed, and the static elimination performance was excellent. In Reference Example 19, since the ratio of the conductive layer responsible for the conductive performance is 30%, the volume resistivity is 2.1 × 10 ³ Ω · cm, the ESR value is 0.30, which is slightly higher than that of Example 1, and the static elimination performance. Although it was slightly inferior, it was a level which is satisfactory practically.

Example 20
The same as in Example 1 except that polyethylene terephthalate copolymerized with 5 mol% of adipic acid (described in the table as “copolymerized PET”) (melting point 243 ° C.) was used as the fiber-forming polyester of the non-conductive layer. The method was evaluated. In the conductive yarn of Example 20, the non-conductive layer forms the outer side of the coil crimp, the volume resistivity is 5.3 × 10 ³ Ω · cm, and the ESR value is 0.25. Although the static elimination performance was slightly inferior, it was at a level where there was no practical problem.

Example 21
Evaluation was performed in the same manner as in Example 1 except that the eccentricity was changed by changing the composite base. The cross section of the conductive yarn is as shown in FIG. 2B, and the eccentricity was 0.04. The volume resistivity was 2.8 × 10 ¹ Ω · cm, the ESR value was 0.03, and the CR value was 3%, which was a conductive yarn having lower crimp characteristics than that of Example 1. The initial charge removal performance was good, but the toner cleaning performance decreased with the number of printings.

Example 22
Evaluation was performed in the same manner as in Example 1 except that the eccentricity was changed by changing the composite base. The cross section of the conductive yarn is as shown in FIG. 2B, and the eccentricity was 0.15. The volume resistivity was 2.9 × 10 ¹ Ω · cm, the ESR value was 0.03, and the CR value was 12%. Although the crimping characteristics were slightly lower than those in Example 1, the sharpness of printing and the toner cleaning performance were not changed from the initial printing to 20,000 sheets, and the static elimination performance was good.

Example 23
Evaluation was performed in the same manner as in Example 1 except that the temperature of the second hot roller during stretching was 120 ° C. The cross section of the conductive yarn was as shown in FIG. 2 (a), and the eccentricity was 0.3. The volume resistivity is 1.5 × 10 ² Ω · cm, ESR value is 0.04, CR value is 18%. From the initial printing to 20,000 sheets, the sharpness of printing and the toner cleaning performance remain the same, and the static elimination performance is excellent. It was.

Example 24
In the same manner as in Example 18 except that the composite die was changed to a side-by-side type, the draw ratio was 2.4 times (NDR × 1.15), and the temperature of the second hot roller in the drawing was 160 ° C. evaluated. The cross section of the conductive yarn was as shown in FIG. The volume resistivity was 7.1 × 10 ⁰ Ω · cm, and the CR value was 47%. In Example 24, brushing was possible, but the quality of the brush was poor. In addition, although the sharpness of printing and toner cleaning performance were somewhat inferior from the initial printing to 20,000 sheets, they were at a level with no practical problems.

Comparative Example 4
Evaluation was performed in the same manner as in Example 24 except that the draw ratio was 2.6 times (NDR × 1.25). The cross section of the conductive yarn was as shown in FIG. The volume resistivity was 2.7 × 10 ¹ Ω · cm, and the CR value was 52%. In Comparative Example 4, crimping was too strong and the brush processability was poor, so that a brush could not be produced.

Example 25
Evaluation was performed in the same manner as in Example 1 except that the temperature of the second hot roller during stretching was set to 100 ° C. The cross section of the conductive yarn is as shown in FIG. 2A, the eccentricity is 0.3, the volume resistivity is 6.8 × 10 ³ Ω · cm, the ESR value is 0.04, the CR value is 16%, and the boiling water is The shrinkage rate was 8.4%. Although the thermal shrinkage was slightly higher than that of Example 1, the sharpness of printing and toner cleaning performance were not changed from the initial printing to 20,000 sheets, and the static elimination performance was good.

Example 26
Evaluation was performed in the same manner as in Example 25 except that the draw ratio was 2.4 times (NDR × 1.15). The cross section of the conductive yarn is as shown in FIG. 2 (a), the eccentricity was 0.3, the volume resistivity was 7.9 × 10 ² Ω · cm, the ESR value was 0.07, and the CR value was 22%. . The boiling water shrinkage was as high as 12.6%, and the volume resistivity after shrinkage was greatly reduced to 2.6 × 10 ¹ Ω · cm. Along with this, the sharpness of printing and the toner cleaning performance deteriorated with time from the initial printing to 20,000 sheets.

Example 27
Evaluation was performed in the same manner as in Example 25 except that the draw ratio was 2.6 times (NDR × 1.25). The cross section of the conductive yarn is as shown in FIG. 2 (a), the eccentricity was 0.3, the volume resistivity was 9.7 × 10 ² Ω · cm, the ESR value was 0.18, and the CR value was 31%. . The boiling water shrinkage was as high as 16.4%, and the volume resistivity after shrinkage was greatly reduced to 2.9 × 10 ¹ Ω · cm. Along with this, the sharpness of printing and the toner cleaning performance deteriorated with time from the initial printing to 20,000 sheets.

Comparative Example 5
Evaluation was performed in the same manner as in Example 1 except that the temperature of the second hot roller in stretching was 110 ° C. The cross section of the conductive yarn is as shown in FIG. 2B, and the eccentricity was 0.04. The volume resistivity is 4.1 × 10 ² Ω · cm, ESR value is 0.04, CR value is 2%, and the conductive yarn has low crimp characteristics. Toner cleanability decreased.

Example 28
As the carbon black used in the conductive layer, Denki Kagaku Kogyo Co., Ltd. acetylene black except for the (type HS-100, a volume resistivity 0.14 · cm, average particle size 48 nm, dibutyl phthalate absorption 140cm ^3/100 g), Evaluation was performed in the same manner as in Example 1. The volume resistivity is 4.7 × 10 ¹ Ω · cm, the ESR value is 0.15, and the CR value is 19%. As in Example 1, the sharpness of printing and the toner cleaning property are changed from the initial printing to 20,000 sheets. It was excellent.

Reference Example 29
As the carbon black used in the conductive layer, except that the Ketjen Black International Co., Ltd. Ketjen Black EC (volume resistivity 0.20Omu · cm, average particle size 38 nm, dibutyl phthalate absorption 405cm ³ / 100g), Example 1 And evaluated in the same manner. In Reference Example 29, the spinnability was lowered, and the yarn breakage was slightly larger than that in Example 1. The obtained conductive yarn had a volume specific resistance of 3.5 × 10 ³ Ω · cm and an ESR value of 0.40. No abnormal discharge trace was observed, but the image was slightly blurred.

Example 30
A brush roller was produced in the same manner as in Example 1 except that the drawn yarn obtained in Example 1 had a twist number of 300 T / m (twisting coefficient: 4450). Example 30 was superior to Example 1 in terms of printing sharpness and toner cleaning properties.

Example 31
A brush roller was produced in the same manner as in Reference Example 19 except that the drawn yarn obtained in Reference Example 19 had a twist number of 500 T / m (twisting coefficient: 7416). In Example 31, the sharpness of printing and the toner cleaning property were stable and superior to those of Reference Example 19.

It is a figure for demonstrating the eccentricity of the eccentric core-sheath-type composite fiber in this invention. It is a figure which shows an example of the cross section of the fiber of this invention. It is a figure for demonstrating the constant tension elongation area elongation as described in Example E term. 1 is a schematic view of a spinning device preferably used in the present invention.

Explanation of symbols

1: A component hopper 1 ': B component hopper 2: A component extrusion kneader (extruder)
2 ': B component extrusion kneader (extruder)
3: Metering pump 4: Spinning block 5: Spin pack 6: Base 7: Cooling device 8: Thread 9: Refueling guide 10: First godet roller 11: Second godet roller 12: Winder 13: Winding Yarn Package A: Non-conductive layer B: Conductive layer

Claims (6)

Containing carbon black, a conductive layer made of a polyester main repeating structural unit is a propylene terephthalate, and non-conductive layer made of a polyester having a fiber formability forms a side-by-side composite or eccentric core-sheath composite, The non-conductive layer is 60% or less of the fiber cross-sectional area, the conductive layer contains carbon black, the weight average molecular weight Mw is 75,000 to 500,000, and the degree of dispersion Mw / Mn is 1.5 to 6. A multifilament composed of a composite fiber in which at least a part of the fiber surface is formed of a certain polyester, and the ratio ESR (ESR = Q / P) between the volume specific resistance P in the yarn length direction and its standard deviation Q There is more than 0.3, and a volume resistivity P is ^{10 -1 ~10 7 Ω · cm,} CR value is characterized by a 3-50% Conductive yarn. Electrically conductive yarn according to claim 1 Symbol placement, wherein the boiling water shrinkage is 0-15%. The ratio of the exposed length of the conductive layer to the circumferential length in the fiber cross section is 50% or more, and the conductive yarn according to claim 1 or 2 Symbol mounting, wherein the conductive layer is outside of the coil crimps. 3. The conductive yarn according to claim 1, wherein the non-conductive layer made of polyester having fiber form has an eccentric core-sheath composite structure in which a core portion is formed. The brush which used the electrically conductive yarn of any one of Claims 1-4 for at least one part. The conductive yarn according to any one of claims 1 to 4 , wherein a twist having a twist coefficient K of 400 to 20,000 is applied.
(However, twist coefficient K = T × D ^0.5
T: number of twists per meter of yarn length,
D: Yarn fineness (dtex)

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