JP2007092200A - Conductive conjugate fiber having moist heat resistance and conductive fabric having moist heat resistance - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To obtain a conductive conjugate fiber that has sufficient conductive performance, slight reduction in conductive performance and strength even after moist heat treatment such as sterilization, etc., and is suitably useful for clothing such as operation uniform for clean room, medical application, interior use such as curtain, etc., and industrial uses. <P>SOLUTION: The conductive conjugate fiber comprises a nonconductive component composed of a polyester-based resin and a conductive component composed of a polyester-based component containing a conductive particle and exhibits a shape in which at least a part of the conductive component is exposed to the surface of the fiber. The conductive conjugate fiber of moist heat resistance has 1×10<SP>6</SP>Q-1×10<SP>9</SP>Q/cm electrical resistivity, ≤20 electroconductivity reduction ratio after moist heat treatment (treatment at 121°C for 25 hours) and ≥75% strength retention after moist heat treatment (treatment at 121°C for 25 hours). <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention is a conductive composite fiber composed of a conductive component and a non-conductive component of a polyester-based resin, and there is little decrease in electrical resistance value or strength after wet heat treatment, antistatic work clothes, uniforms, etc. The present invention relates to a heat-and-moisture resistant conductive conjugate fiber that can be suitably used for clothing, interiors such as curtains, and industrial materials.

  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 lower the aesthetics, give an electric shock to the human body, and cause discomfort. Problems such as obstacles and flammable explosions on flammable substances can be caused, and many studies have been conducted to impart conductivity to solve these problems.

  Patent Document 1 describes a core-sheath type composite fiber in which a conductive component containing conductive particles such as conductive 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 fibers have been used in clean room work uniforms, medical uniforms, and the like. In such applications, sterilization is repeatedly performed by an autoclave. When the conductive composite fiber has a conductive component arranged in the sheath as described above, there is a problem that the conductive fiber is cracked by repeating the sterilization treatment, and further the conductive component is missing. There was a decrease in the conductive performance after sterilization, and a decrease in strength due to fiber deterioration.

As described above, in applications where wet heat treatment is performed by an autoclave, cracks in the fiber surface and lack of conductive components are unlikely to occur, and there is little decrease in electrical conductivity and strength due to fiber deterioration, which is sufficient for long-term use. Conductive fibers having conductive performance have not been developed yet.
JP 09-143821 A WO2002 / 075030

  The present invention solves the problems as described above, has sufficient conductive performance, and has little decrease in conductive performance and strength even after wet heat treatment such as sterilization treatment, and is used for clean room and medical work. It is a technical problem to provide a moisture and heat resistant conductive composite fiber and a moisture and heat resistant conductive fabric that can be suitably used for clothing such as uniforms for clothing, interior use such as curtains, and materials.

  The inventors of the present invention have arrived at the present invention as a result of studies to solve the above problems. That is, the gist of the present invention is the following (1) and (2).

(1) A shape composed of a non-conductive component made of a polyester-based resin and a conductive component made of a polyester-based resin containing conductive particles, wherein at least a part of the conductive component is exposed on the fiber surface. It is a conductive composite fiber that has an electrical resistance value of 1 × 10 ⁶ Ω to 1 × 10 ⁹ Ω / cm, and a decrease in conductivity performance of 20 or less after wet heat treatment (treatment at 121 ° C. for 25 hours) A wet heat resistant conductive composite fiber characterized by having a strength retention of 75% or more after wet heat treatment (treated at 121 ° C. for 25 hours).

(2) Moisture and heat resistance, characterized in that the fabric uses at least part of the moisture and heat resistant conductive conjugate fiber according to (1), and has a surface leakage resistance value of 1 × 10 ⁶ Ω to 1 × 10 ^9. Conductive fabric.

  Hereinafter, the present invention will be described in detail.

  The conductive composite fiber of the present invention (hereinafter abbreviated as heat and heat resistant conductive composite fiber) is composed of a nonconductive component made of a polyester resin and a conductive component made of a polyester resin containing conductive particles. It is what is done. The composite form of the conductive conjugate fiber of the present invention will be described with reference to the drawings. 1-3 show the cross-sectional shape cut | disconnected perpendicularly | vertically with respect to the longitudinal direction of the fiber of the electroconductive composite fiber of this invention.

  In the conductive conjugate fiber of the present invention, at least a part of the conductive component is exposed on the fiber surface.

  As shown in FIG. 1, the conductive component covers the entire fiber surface, that is, the sheath is a conductive component and the core is a non-conductive component in a core-sheath shape, or as shown in FIG. 2. In addition, a shape in which a part of the conductive component is exposed on the fiber surface can be mentioned. When the wet heat treatment is repeatedly performed, the shape of FIG. 2 and FIG. 3 in which the conductive component covers a part of the fiber surface is preferable as the shape in which the conductive component is less likely to generate cracks or drop off.

  As shown in FIGS. 2A to 2D, a part of the conductive component is exposed on the fiber surface and a part of the fiber surface is covered with the conductive component. A conductive component is present in a non-conductive component, and a part of the conductive component (one side of a substantially triangular shape) is exposed on the fiber surface. The shape of the conductive component is not particularly limited, and may be quadrangular or semicircular.

  FIG. 2 (a) shows that the number of the conductive components is one and the portion exposed on the fiber surface is one, and (b) shows that the number of the conductive components is two and exposed on the fiber surface. There are two places, (c) is three places where the number of conductive components is exposed on the fiber surface, and (d) is four places where the number of conductive components is exposed on the fiber surface. This is an example where there are four locations.

  As for the location exposed to the fiber surface of an electroconductive component, 2-20 locations are preferable, and it is preferable that it is 3-8 locations especially. When the portion exposed on the fiber surface of the conductive component is one place, the portion exposed on the fiber surface is subjected to a wet heat treatment, and when cracks occur or are damaged or missing, In some cases, the conductive performance becomes insufficient, and the original conductive performance cannot be maintained. On the other hand, when the number of the exposed portions of the conductive component on the fiber surface exceeds 20, the exposed portion on the fiber surface increases, and cracks and missing after the wet heat treatment tend to occur. For this reason, the ratio of exposure of the conductive component to the fiber surface is preferably 3/4 or less of the circumference, more preferably 1/2 or less, and more preferably 1/3 to 1/10. When it is less than 1/10 of the circumference, the conductive performance tends to be insufficient, which is not preferable.

  Furthermore, as the shape of the conductive conjugate fiber of the present invention, there are two or more portions exposed on the fiber surface of the conductive component, and the conductive component has a shape communicating with the vicinity of the fiber center portion. preferable. As an example, the ones shown in FIGS. In FIG. 3A, the conductive component is arranged in a straight line through the vicinity of the center of the fiber, and there are two portions exposed on the fiber surface. In (b), the conductive component is arranged in a cross shape through the vicinity of the center of the fiber, and there are four portions exposed on the fiber surface. In (c), the conductive component is arranged in a shape divided into three sides through the vicinity of the center of the fiber, and there are three portions exposed on the fiber surface.

  As described above, the conductive component communicates in the vicinity of the center of the fiber and is exposed at two or more positions on the fiber surface, so that there are a large number of conductive contacts on the fiber surface, and the center between the contacts is present. Since electrical flow is possible in multiple directions by conducting through the section, it is possible to obtain a fiber having excellent conductivity. For this reason, it is preferable that the part exposed to the fiber surface of an electroconductive component shall be 3 or more places especially. However, when the number of exposed portions increases, the exposed portion on the fiber surface increases, and cracks and omissions after sterilization are likely to occur. Further, the ratio of exposure of the conductive component to the fiber surface is preferably 3/4 or less, more preferably 1/2 or less, more preferably 1/3 to 1/1 of the circumference for the same reason as described above. 10.

  In the composite fiber of the present invention, the composite ratio of the nonconductive component and the conductive component is preferably 60 to 90% by mass for the nonconductive component and 40 to 10% by mass for the conductive component. Preferably, the non-conductive component is 70 to 85% by mass and the conductive component is 30 to 15% by mass. When the composite ratio of the conductive component is less than 10% by mass, the conductive performance may not be sufficient. On the other hand, when the composite ratio of the conductive component exceeds 40% by mass, the yarn quality performance such as the strong elongation property is inferior. Or troubles during operation and cracks after sterilization.

The conductive conjugate fiber of the present invention preferably has an electrical resistance value of 1 × 10 ⁶ Ω / cm to 1 × 10 ⁹ Ω / cm, particularly 1 × 10 ⁷ Ω / cm to 1 as the conductive performance. × 10 ⁹ Ω / cm is preferable. When the electrical resistance value of the composite fiber exceeds 1 × 10 ⁹ Ω / cm, the conductive performance becomes insufficient, and the effect of preventing the fabric from being charged becomes small when the resulting fabric is used in a normal environment. On the other hand, if it is attempted to make it less than 1 × 10 ⁶ Ω / cm, it is necessary to contain a large amount of conductive particles in the polymer, and troubles are likely to occur during spinning and stretching.

In addition, the electrical resistance value of the conductive conjugate fiber in the present invention is measured as follows according to the AATCC76 method. Conductive conjugate fiber (which may be either multifilament or single yarn) is cut to about 15 cm in the length direction, and 10 samples are collected. Apply keratin cream to the surface of both ends of this sample, connect this surface part to a metal terminal, apply a 50V direct current with a sample measurement length of 10 cm, and measure the current value. Is calculated. The arithmetic average value of the calculated electric resistance values of 10 samples is used.
Electric resistance value = E / (I × L)
E: Voltage (V) I: Measurement current (A) L: Measurement length (cm)

  Next, the performance after the wet heat treatment (treatment at 121 ° C. for 25 hours) of the conductive conjugate fiber of the present invention will be described. The rate of decrease in conductive performance after wet heat treatment is 20 or less, and the strength retention is 75% or more. With the shape of the fiber as described above, and further by reducing the carboxyl end group concentration of the conductive conjugate fiber, even if the moisture treatment such as sterilization treatment is repeated, the conductivity performance decreases before and after that and It is possible to obtain a fiber with almost no decrease in strength.

  Specifically, the carboxyl end group concentration of the conductive conjugate fiber is preferably 25 geq / t or less, more preferably 20 geq / t or less, and further preferably 18 geq / t or less. When the carboxyl end group concentration is higher than 25 geq / t, it becomes inferior in heat-and-moisture resistance, and tends to fail to satisfy the rate of decrease in conductivity performance and strength retention.

  In order to set the carboxyl end group concentration of the conductive conjugate fiber to 25 geq / t or less, it is preferable to set the carboxyl end group concentration of at least one of the non-conductive component and the conductive component to 25 geq / t or less. Above all, by setting the carboxyl end group concentration of the conductive component to 25 geq / t or less, it becomes difficult for cracks to occur in the conductive component even after repeated wet heat treatment, and the loss or dropping of the conductive particles is less likely to occur. It can be set as the electroconductive fiber which has the heat-and-moisture resistant performance which is not in a fiber.

  Further, even if the conductive component is a core-sheath shape in which the conductive component is a sheath as shown in FIG. 1 or the conductive component is partially exposed to the fiber surface as shown in FIG. Since the conductive component on the fiber surface is easily damaged by wet heat treatment, the carboxyl end group concentration of both the conductive component and the nonconductive component is preferably 25 geq / t or less.

  In the present invention, the carboxyl end group concentration of the conductive conjugate fiber is as follows: 0.1 g of conductive conjugate fiber is dissolved in 10 ml of benzyl alcohol, 10 ml of chloroform is added to this solution, and then 1/10 N potassium hydroxide benzyl alcohol solution is used. It is determined by titration.

  In order to reduce the carboxyl end group concentration of the conductive conjugate fiber, a method of adding an end-blocking agent during spinning, polymerization conditions in solid phase polymerization or melt polymerization of conductive components and non-conductive components (catalyst amount, temperature, etc.) ) And the like. Specific examples of the end-capping agent include carbodiimide compounds such as N, N′-bis (2,6-diisopropylphenyl) carbodiimide) and epoxy compounds such as phenyl glycidyl ether.

  Usually, sterilization with high-pressure steam is performed periodically (repeatedly) on surgical clothes, lab coats, food factory uniforms, etc. used in hospitals. Steam treatment at that time, that is, wet heat treatment temperature is 121 ° C. to 135 ° C., and the treatment time is generally about 15 to 5 minutes as the time required for sterilization.

  Since the time required for the wet heat treatment (once) at 121 ° C. is usually about 15 minutes, in the present invention, the conductive performance and strength before and after the treatment are performed by performing a 25 hour treatment corresponding to 100 wet heat treatments. It is used as an index to see the degree of decrease in

First, the rate of decrease in conductive performance after wet heat treatment (treated at 121 ° C. for 25 hours) in the conductive conjugate fiber of the present invention is calculated as follows.
Conductive performance degradation rate = (Y / X)
X: Electrical resistance value of conductive composite fiber before wet heat treatment (Ω / cm)
Y: Electrical resistance value after wet heat treatment of conductive composite fiber (Ω / cm)

  The conductive conjugate fiber of the present invention has a conductive performance reduction rate of 20 or less, and preferably 10 or less. Normally, when the rate of decrease in conductivity performance exceeds 100, the fiber becomes a fiber whose electric resistance value is greatly reduced by wet heat treatment such as sterilization treatment. Even if it has conductivity performance before treatment, it has conductivity performance after treatment. In other words, the durability is inferior and the conductive performance cannot be sufficiently exhibited in each application. By being 20 or less, there is almost no deterioration in the conductive performance, and the durability is extremely excellent.

Furthermore, the strength retention after the moisture treatment in the conductive conjugate fiber of the present invention is determined by grasping the tensile strength of the fiber using a constant speed extension type tester according to the standard time test of tensile strength and elongation rate of JIS-L1013. Measure at an interval of 20 cm. Next, after performing wet heat treatment at 121 ° C. for 25 hours, the strength of the fiber is obtained again by the same method. And it calculates as follows.
Strength retention (%) = (S / M) × 100
S: Tensile strength (cN / dtex) after wet heat treatment of conductive composite fiber
M: Tensile strength of conductive composite fiber before wet heat treatment (cN / dtex)

  The strength retention is preferably 75% or more, more preferably 80% or more. In the fiber obtained by a conventional method, the strength retention is 50% or less. In this case, as the sterilization process is repeated, the decrease in strength increases, and damage is caused by a load caused by wearing, so that the fibers are cut or the quality deteriorates, and at the same time, the conductive performance also decreases. When the strength retention is 75% or more, an excellent performance with almost no decrease in strength can be obtained even after wet heat treatment.

  Next, each component which comprises the electroconductive composite fiber of this invention is demonstrated. First, the conductive component will be described.

  As the polyester resin of the conductive component, polyethylene terephthalate (PET), polybutylene terephthalate (PBT) or the like can be used, and those singly or blended or copolymerized can also be used.

  Among these, since it is excellent in heat and heat resistance, it is preferable to use PET, and PET having an ethylene terephthalate repeating unit of 85 mol% or more is preferable. When the ethylene terephthalate repeating unit is less than 85 mol%, the heat and moisture resistance tends to decrease, such being undesirable.

  And, compared to PBT, PET has a lower kneading property of conductive particles, but by containing a small amount of a specific copolymer component, the content of conductive particles can be increased, and the conductive performance is improved. Therefore, if it is 15 mol% or less, it may contain a copolymer component.

  As such a copolymerization component, isophthalic acid and adipic acid are preferable, and it is preferable to copolymerize either one or both as a copolymerization component. Thereby, the compatibility (surface wettability) between the conductive component and the conductive particles can be improved, the mixing amount of the conductive particles can be increased, and excellent conductive performance can be obtained. Furthermore, the flexibility of the polymer is improved, the spinning and drawing process can be performed smoothly, and the conductive performance can be uniform in the length direction.

  The conductive particles contained in the conductive component include carbon black, metal powder (silver, nickel, copper, iron, tin or alloys thereof), copper sulfide, copper iodide, zinc sulfide, cadmium sulfide, etc. The metal compound of these is mentioned. In addition, a small amount of antimony oxide may be added to tin oxide, or a small amount of aluminum oxide may be added to zinc oxide to form conductive particles.

  Furthermore, it is also possible to use a conductive particle obtained by coating the surface of titanium oxide with tin oxide and mixing and baking antimony oxide. Among these, carbon black (acetylene black, ketjen black, etc.) that is generally used for improving the performance of conductive fibers and hardly inhibits the polymer fluidity as compared with other metal particles.

  The particle size of the conductive particles is not particularly limited, but it is preferable that the average particle size is 1 μm or less. When it exceeds 1 μm, the dispersibility of the conductive particles in the polymer tends to be deteriorated, and the fiber tends to have a deteriorated conductive performance and high elongation property.

  The content of the conductive particles in the conductive component may be appropriately selected depending on the type of conductive particles, conductive performance, particle diameter, particle chain-forming ability, and characteristics of the polymer used. It is preferable to set it as -40 mass%, More preferably, it is 10-30 mass%. If the content is less than 5% by mass, the conductive performance may be insufficient, and if it exceeds 40% by mass, it is difficult to disperse the conductive particles in the polymer.

  Furthermore, the conductive component includes a dispersant, an antioxidant, an ultraviolet absorber, such as waxes, polyalkylene oxides, various surfactants, organic electrolytes, etc., as long as the effects of the present invention are not impaired. Stabilizers, colorants, pigments, fluidity improvers, and other additives can also be added.

  Next, as the polyester resin of the non-conductive component, any polyester polymer that can be melt-spun can be applied. However, as described above, it is preferable to use PET from the viewpoint of moisture and heat resistance. 85 mol% or more of PET is preferred. When the ethylene terephthalate repeating unit is less than 85 mol%, the heat and moisture resistance tends to decrease, such being undesirable.

  In addition, the non-conductive component polyester-based resin can be dispersed within a range that does not impair the effect, waxes, polyalkylene oxides, various surfactants, organic electrolytes and other dispersants and antioxidants, Stabilizers such as ultraviolet absorbers, colorants, pigments, fluidity improvers, and other additives can also be added.

  The conductive conjugate fiber of the present invention may be a multifilament composed of a plurality of fibers, a monofilament used only with a single yarn, or may be a long fiber or a short fiber.

  In addition, the conductive conjugate fiber of the present invention may be processed yarn that is twisted and mixed with other fibers. Other fibers are not particularly limited, and examples thereof include synthetic fibers such as polyamide, polyester, and polyethylene, regenerated fibers such as rayon, and natural fibers such as cotton, hemp, and wool. Among them, polyester fibers that are the same as conductive composite fibers Is preferable in view of the durability of the wet heat treatment.

  Next, the manufacturing method of the electroconductive composite fiber of this invention is demonstrated. First, as a method for obtaining a conductive component, a method in which conductive particles are added in the polymerization stage of the polymer or a polymer in which conductive particles are added in high concentration in advance are prepared and added to the polymer after polymerization. However, since it is difficult to add conductive particles in the polymerization stage depending on the polymer used, the latter method is preferred. And in order to reduce the carboxyl end group concentration of the non-conductive component or the conductive component, as described above, the carboxyl end group concentration was decreased by a method of adjusting the polymerization conditions or a method of adding a terminal blocking agent. The polyester component. The conductive component and the non-conductive component thus obtained are subjected to a treatment such as drying to form a chip, and composite spinning is performed using an ordinary two-component composite melt spinning apparatus. At this time, about the shape and arrangement position of a nonelectroconductive component or a conductive component, it is set as the composite fiber of desired cross-sectional shape by changing a spinneret shape variously. And the electroconductive composite fiber of this invention can be obtained by extending | stretching and heat-processing the obtained thread | yarn.

Next, the conductive fabric of the present invention will be described. The conductive fabric of the present invention is a fabric using at least a part of the conductive conjugate fiber of the present invention as described above, and the surface leakage resistance value indicating the electrical resistance value of the fabric is 1 × 10 ⁶ Ω to 1 It is a thing of * 10 < ⁹ >, and it is preferable that it is especially 1 * 10 < ⁷ > (omega | ohm)-1 * 10 < ⁸ >.

  The proportion of the conductive conjugate fiber of the present invention in the conductive fabric of the present invention is preferably 0.1 to 5.0% by mass. If it is less than 0.1% by mass, it tends to be difficult to impart sufficient electrical conductivity to the fabric. On the other hand, if it exceeds 5.0% by mass, there is no problem in the texture as a fabric, etc., but since the conductive performance is sufficiently imparted, it tends to be disadvantageous in terms of cost.

  Examples of the conductive fabric of the present invention include woven and knitted fabrics, nonwoven fabrics, and various sheets.

  In the case of a woven fabric, it is preferable that the conductive conjugate fiber of the present invention is used for either one or both of the warp and the weft and the conductive conjugate fiber is arranged in the fabric at an interval of 10 mm or less, more preferably 5 mm or less. The woven structure is not particularly limited, and examples thereof include plain weave, twill weave, and entangled weave.

  In the case of a knitted fabric, any of a circular knitting, a weft knitting, and a warp knitting may be used. In the case of a circular knitting or a weft knitting, the conductive conjugate fiber of the present invention is inserted in a border shape at intervals of 10 mm or less, more preferably 5 mm or less. It is preferable to do. Also in the case of warp knitting, it is preferable to insert the conductive conjugate fibers of the present invention in stripes at intervals of 10 mm or less, more preferably 5 mm or less.

  In the case of a non-woven fabric, the conductive conjugate fiber of the present invention is made into a short fiber shape and mixed with other fibers to make a nonwoven fabric, or the conductive conjugate fiber of the present invention is inserted into a nonwoven fabric obtained from other fibers. It is preferable.

The conductive fabric of the present invention has a surface leakage resistance value indicating the electrical resistance value of the fabric of 1 × 10 ⁶ Ω to 1 × 10 ⁹ , and the conductive conjugate fiber of the present invention is used at least in part. Therefore, the surface leakage resistance value after wet heat treatment (treatment at 121 ° C. for 25 hours) is also preferably 1 × 10 ⁶ Ω to 1 × 10 ⁹ , and more preferably 1 × 10 ⁷ Ω to 1 × 10 ⁸ . The surface leakage resistance value is measured in accordance with JIS L 1094 “Reference Surface Leakage Resistance Measurement Method / Kringing Measurement Method”.

When the surface leakage resistance value of the conductive cloth of the present invention is more than 1 × 10 ⁹ Ω / cm, the conductive performance becomes insufficient, when the fabric obtained was used under normal circumstances, to prevent charging of the fabric The effect is poor. On the other hand, if the density is less than 1 × 10 ⁶ Ω / cm, it is necessary to contain a large amount of conductive particles in the polymer in the conductive composite fiber, which not only adversely affects the fiber properties as described above, but also spinning. Troubles easily occur during stretching.

  The conductive conjugate fiber of the present invention has a low electrical resistance value, has sufficient conductive performance and strength, and has little decrease in conductive performance and strength even after wet heat treatment such as sterilization treatment. For this reason, it becomes possible to use suitably in various uses which perform wet heat treatment repeatedly.

  And since the electroconductive cloth of this invention uses the electroconductive composite fiber of this invention for a part, it will have the outstanding heat-and-moisture resistance performance and yarn quality performance. Therefore, the conductive composite fiber and the conductive woven or knitted fabric of the present invention are required to have an antistatic effect and need to be repeatedly subjected to wet heat treatment such as sterilization treatment, such as clothing for clean rooms and medical work uniforms. It can be suitably used for applications, interior applications such as curtains, and material applications.

Next, the present invention will be described specifically by way of examples. In addition, measurement and evaluation of various values in the examples were performed as follows.
1. The electrical resistance value, the conductive performance reduction rate, and the strength retention rate of the conductive conjugate fiber were measured and calculated according to the method described above. In addition, after creating a tubular knitted fabric using the obtained conductive conjugate fiber, a surfactant (Nikko Chemical's Sunmol FL) was used at a concentration of 1 g / l, and scouring treatment was performed at 80 ° C. for 30 minutes. After the treatment, it is treated with hot water at 130 ° C. for 30 minutes. Thereafter, as wet heat treatment, the cylindrical knitted fabric was continuously treated at 121 ° C. for 25 hours using a high-pressure steam sterilizer (HV-50 manufactured by Hirayama Seisakusho). The electrical resistance value of the conductive composite fiber before creating the tubular knitted fabric is taken as the electrical resistance value before the wet heat treatment, and the electrical resistance value of the conductive composite fiber taken out by weaving the tubular knitted fabric after the wet heat treatment is wet. The electrical resistance value after the heat treatment was used.
2. Surface leakage resistance value of conductive fabric (before and after wet heat treatment)
Using the obtained fabric, the surface leakage resistance value was measured according to the method described above. In addition, 1. Using the same high-pressure steam sterilizer, the wet heat treatment was continuously performed at 121 ° C. for 25 hours, and the surface leakage resistance value after the wet heat treatment was measured in the same manner.
3. Carboxyl end group concentration The carboxyl end group concentration of the conductive component, non-conductive component, and conductive composite fiber was measured by the method described above.

Example 1
PET (substantially ethylene terephthalate repeating unit) with an intrinsic viscosity of 0.67 (measured at a temperature of 20 ° C using an equimolar mixture of phenol and ethane tetrachloride) as a conductive component and a carboxyl end group concentration of 30 geq / t 100 mol%) and carbon black with an average particle size of 0.2 μm (25% by mass in the conductive component) melted and kneaded as conductive particles into chips by a conventional method. It was. In addition, as a non-conductive component, terephthalic acid and ethylene glycol were subjected to a polycondensation reaction to obtain a prepolymer pellet, and further obtained by performing a solid phase polymerization reaction at 220 ° C. for 20 hours. The intrinsic viscosity was 0.64 and the carboxyl end group concentration was Using 9geq / t PET (substantially 100 mol% ethylene terephthalate repeating unit), chips were formed in the same manner in the same manner as non-conductive components.
Next, using a spinneret designed so that the cross-sectional shape of the single yarn is as shown in FIG. 2 (c), the chips of the conductive component and the non-conductive component are supplied, and the spinning temperature from a normal composite spinning device. Spinning was performed at 295 ° C. so that the composite ratio of conductive components was 20% by mass, and winding was performed at a speed of 3000 m / min while cooling and oiling to obtain 43 dtex / 2f undrawn yarn. Then, the undrawn yarn was drawn 1.53 times through a 90 ° C. heat roller, further heat treated with a heat plate at 190 ° C., and wound up to give 28 dtex having the cross-sectional shape of FIG. / 2 conductive composite fiber was obtained.

Example 2
As the conductive component, PBT having an intrinsic viscosity of 0.67 and a carboxyl end group concentration of 24 geq / t was used instead of PET, and carbon black having an average particle size of 0.2 μm (30% by mass in the conductive component) A conductive conjugate fiber was obtained in the same manner as in Example 1 except that the composition was melt-kneaded and converted into a chip by a conventional method to obtain a conductive component.

Example 3
Conducted in the same manner as in Example 1 except that a spinneret designed so that the cross-sectional shape of the single yarn is as shown in FIG. 3C was used, and a 28 dtex / 2 conductive material having the cross-sectional shape shown in FIG. A functional composite fiber was obtained.

Example 4
As the conductive component, instead of PET, PET (extreme viscosity 0.67, carboxyl end group concentration of 25 geq / t) copolymerized with 5% by mole of isophthalic acid is used as the copolymer component. A conductive conjugate fiber was obtained in the same manner as in Example 3 except that 0.2 μm of carbon black (amount of 30% by mass in the conductive component) was melt-kneaded and converted into a chip by a conventional method to obtain a conductive component. It was.

Example 5
As a non-conductive component, a prepolymer pellet obtained by polycondensation reaction of terephthalic acid and ethylene glycol was subjected to a solid phase polymerization reaction at 220 ° C. for 16 hours. The intrinsic viscosity was 0.64 and the carboxyl end group concentration was 12 geq / t. A conductive conjugate fiber was obtained in the same manner as in Example 1 except that PET (substantially 100 mol% of ethylene terephthalate repeating unit) was used.

Example 6
As a conductive component, polycondensation reaction of terephthalic acid and ethylene glycol was made into prepolymer pellets, and further obtained by conducting a solid phase polymerization reaction at 220 ° C. for 24 hours, an intrinsic viscosity of 0.67 and a carboxyl end group concentration of 7 geq / t PET (substantially 100 mol% ethylene terephthalate repeating unit) melted and kneaded with carbon black having an average particle size of 0.2 μm (25% by mass in the conductive component) as conductive particles A conductive conjugate fiber was obtained in the same manner as in Example 1 except that the chip was formed into a conductive component by a conventional method.

Comparative Example 1
Using a spinneret designed so that the cross-sectional shape of a single yarn is a core-sheath type as shown in FIG. 4, a conductive component is disposed in the core and a non-conductive component is disposed in the sheath, and the non-conductive component As in Example 1, except that PET having an intrinsic viscosity of 0.64 and a carboxyl end group concentration of 12 geq / t obtained by changing the solid phase polymerization time (220 ° C., 16 hours) was used. Fiber was obtained.

Comparative Example 2
A conductive conjugate fiber was obtained in the same manner as in Example 1 except that PET having an intrinsic viscosity of 0.64 and a carboxyl end group concentration of 37 geq / t was used as the non-conductive component.

Comparative Example 3
A conductive conjugate fiber was obtained in the same manner as in Example 3 except that PET having the same intrinsic viscosity of 0.64 as in Comparative Example 2 and a carboxyl end group concentration of 37 geq / t was used as the non-conductive component.

  Table 1 shows the measurement results of various values of the conductive conjugate fibers obtained in Examples 1 to 6 and Comparative Examples 1 to 3.

As is clear from Table 1, the conductive conjugate fibers of Examples 1 to 6 had a low electrical resistance value before and after the wet heat treatment, a low rate of decrease in conductive performance, and an excellent conductive performance. Moreover, the strength before and after the wet heat treatment was high, the strength retention was high, and the yarn quality was excellent.

  On the other hand, the conductive conjugate fiber of Comparative Example 1 had a core-sheath shape, and the conductive component was disposed only in the core portion, so that the conductive performance was insufficient. In addition, the conductive conjugate fibers of Comparative Examples 2 and 3 had high moisture endurance performance because the carboxyl end group concentration of the non-conductive component and the conductive component was high and the carboxyl end group concentration of the conductive conjugate fiber was also high. In addition, the electrical resistance value after the wet heat treatment was high, the strength was low, the rate of decrease in conductive performance was high, and the strength retention was low.

Example 7
Using an 84 dtex / 36 f multifilament (yarn B) made of ordinary PET and the conductive composite fiber obtained in Example 1, 300 T / M is twisted in the S direction by a twister and the yarn is subjected to twisting. A. A warp yarn was prepared for the yarn A and the yarn B in a ratio of 1:29. As the wefts, the same yarns A and B as the warp yarns were used and woven in a water jet loom to obtain a plain fabric in which the ratio of the yarns A and B was 1:19. The green density at this time was 150 warps / 2.54 cm and 95 wefts / cm.
Further, refining, pre-setting, and dyeing are performed on the above-described plain woven fabric by a known method, and the finishing set is performed so that the yarns A including conductive fibers are arranged one by one at intervals of about 5 mm for both warp and weft. A conductive fabric (100 g / cm ² basis weight) was produced. The finishing density at this time was 165 warps / 2.54 cm and 105 wefts / 2.54 cm.

Comparative Example 4
A conductive fabric was obtained in the same manner as in Example 7, except that the conductive conjugate fiber used in Example 7 (obtained in Example 1) was changed to the conductive conjugate fiber obtained in Comparative Example 2. It was.

Example 8
Using a 28-gauge tricot knitting machine, using nylon 6 yarn (fineness 78 dtex / 24f) for the front part in the marquezet structure, and obtaining 5 nylon 6 yarns (fineness 44 dtex / 12f) for the back part in Example 3 One twisted yarn obtained in the same manner as in Example 7 using the conductive composite fiber was used, and the resultant was knitted so as to have a total of six repeated arrangements. Next, refining and dyeing were performed by a known method to obtain an untreated conductive knitted fabric. The green density at this time was 50 courses / 2.54 cm and 30 wales / 2.54 cm.

Comparative Example 5
A conductive knitted fabric was obtained in the same manner as in Example 8, except that the conductive conjugate fiber used in Example 8 (obtained in Example 3) was changed to the conductive conjugate fiber obtained in Comparative Example 3. It was.

  Table 2 shows the measurement and evaluation results of the conductive fabrics obtained in Examples 7 to 8 and Comparative Examples 4 to 5.

As apparent from Table 2, since the fabrics of Examples 7 to 8 were obtained by using a part of the conductive conjugate fiber of the present invention, the surface leakage resistance values before and after the wet heat treatment were sufficient. It was of a value and had sufficient electrical conductivity performance and heat-and-moisture resistance performance.

  On the other hand, since the fabrics of Comparative Examples 4 to 5 were partially made of conductive composite fibers having insufficient conductive performance after wet heat treatment, the surface leakage resistance value after wet heat treatment was high, and sufficient conductive performance. It did not have.

It is the cross-sectional schematic diagram cut | disconnected perpendicularly | vertically with respect to the longitudinal direction of the fiber which shows one embodiment of the electroconductive composite fiber of this invention. It is the cross-sectional schematic diagram cut | disconnected perpendicularly | vertically with respect to the longitudinal direction of the fiber which shows the other embodiment of the electroconductive composite fiber of this invention. It is the cross-sectional schematic diagram cut | disconnected perpendicularly | vertically with respect to the longitudinal direction of the fiber which shows the other embodiment of the electroconductive composite fiber of this invention. It is the cross-sectional schematic diagram cut | disconnected perpendicularly | vertically with respect to the longitudinal direction of the fiber which shows one embodiment of the conventional electroconductive composite fiber.

Claims (7)

It is composed of a non-conductive component made of a polyester-based resin and a conductive component made of a polyester-based resin containing conductive particles, and has a shape in which at least a part of the conductive component is exposed on the fiber surface. An electrically conductive conjugate fiber having an electrical resistance value of 1 × 10 ⁶ Ω to 1 × 10 ⁹ Ω / cm, a rate of decrease in conductive performance after wet heat treatment (treated at 121 ° C. for 25 hours) is 20 or less, A moist and heat resistant conductive composite fiber characterized by having a strength retention of 75% or more after wet heat treatment (treated at 121 ° C for 25 hours). The wet heat resistant conductive conjugate fiber according to claim 1, wherein the carboxyl end group concentration of the conductive conjugate fiber is 25 geq / t or less. The wet heat resistant conductive composite fiber according to claim 1 or 2, wherein at least one of the non-conductive component and the conductive component has a carboxyl end group concentration of 25 geq / t or less. The wet heat resistant conductive composite fiber according to any one of claims 1 to 3, wherein at least one of the non-conductive component and the conductive component is polyethylene terephthalate having an ethylene terephthalate repeating unit of 85 mol% or more. The place exposed to the fiber surface of an electroconductive component is 2-20 places, The heat-and-moisture resistant conductive composite fiber in any one of Claims 1-4. 6. The moisture and heat resistant conductive composite fiber according to claim 1, wherein the conductive component has two or more exposed portions on the fiber surface and has a shape communicating with the vicinity of the center of the fiber. A fabric using at least a part of the moisture and heat resistant conductive conjugate fiber according to claim 1, wherein the surface leakage resistance value is 1 × 10 ⁶ Ω to 1 × 10 ^9. Moist heat resistant conductive fabric.