JP4763450B2 - Moist heat resistant conductive composite fiber - Google Patents

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 is such that the conductive component is arranged in the sheath as described above, there is a problem that the conductive component 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 heat-and-moisture resistant conductive composite fiber that can be suitably used for clothing such as uniforms for clothing, interior use such as curtains, and material use.

  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 present invention is a non-conductive component comprising polyethylene terephthalate copolymerized with 5 to 20 mol% of at least one component among isophthalic acid, cyclohexanedimethanol and cyclohexanedicarboxylic acid, isophthalic acid, cyclohexanedimethanol, cyclohexanedicarboxylic acid. It is composed of polybutylene terephthalate copolymerized with 5 to 40 mol% of at least one component and containing conductive particles, and at least a part of the conductive component is exposed on the fiber surface. A conductive composite fiber having a shape in which the antimony compound and the phosphorus compound are contained in the conductive composite fiber in such an amount that simultaneously satisfies the following formulas (1) to (2), and the electrical resistance value: 1 × 10 ⁴ Ω to 1 × 10 ⁷ Ω / cm, conductivity after wet heat treatment (treated at 121 ° C. for 25 hours) A moist heat resistant conductive composite fiber characterized by having a performance degradation rate of 20 or less and a strength retention after wet heat treatment (treated at 121 ° C. for 25 hours) of 70% or more.
(1) 0.5 × 10 ⁻⁴ ≦ [Sb] ≦ 3.0 × 10 ⁻⁴
(2) 0.1 × 10 ⁻⁴ ≦ [P] ≦ 20.0 × 10 ⁻⁴
In addition, [Sb] represents the content of the antimony compound, [P] represents the content of the phosphorus compound,
The unit is “mol / acid component mol”.

  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 is a schematic diagram showing a cross-sectional shape cut perpendicularly to the longitudinal direction of the fiber of the conductive conjugate fiber of the present 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. The shape of FIG. 2 and FIG. 3 in which a conductive component covers a part of the fiber surface as the shape in which cracking and falling off of the conductive composite fiber are difficult to occur when repeated wet heat treatment is performed. .

  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, a fiber having excellent conductivity can be obtained. 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 composite fiber of the present invention, as the conductive performance, the electric resistance value is ^{1 × 10 4 Ω / cm~1 ×} 10 7 Ω / cm, inter alia ^{1 × 10 4 Ω / cm~1 ×} 10 6 It is preferably Ω / cm. When the electrical resistance value of the composite fiber exceeds 1 × 10 ⁷ Ω / cm, the conductive performance becomes insufficient depending on the application to be used. When the electrical resistance value of the conductive conjugate fiber is 1 × 10 ⁷ Ω / cm or less, when the obtained woven or knitted fabric is used in a normal environment, the knitted or knitted fabric can be hardly charged. On the other hand, if it is attempted to make it less than 1 × 10 ⁴ Ω / cm, it is necessary to contain a large amount of conductive particles in the polymer, which not only adversely affects the physical properties of the fiber but also easily causes troubles 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 70% or more. By adopting the shape of the fiber as described above, and further by using a conductive composite fiber containing a specific amount of an antimony compound and a phosphorus compound, the carboxyl end group concentration can be reduced, and moisture treatment such as sterilization treatment Even if it repeats, it can be set as the fiber which hardly has the fall of the electroconductive performance and the intensity | strength before and behind that.

  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 70% or more, more preferably 75% or more. In the fiber obtained by a conventional method, the strength retention becomes 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 70% or more, an excellent performance with almost no decrease in strength can be obtained even after wet heat treatment.

  And the electroconductive composite fiber of this invention contains the amount which an antimony compound and a phosphorus compound satisfy | fill simultaneously following formula (1)-(2) in a fiber. As a result, the conductive conjugate fiber of the present invention has resistance to moist heat, has the conductivity reduction rate and strength retention after the wet heat treatment as described above, and has excellent color tone. .

  Examples of the antimony compound include antimony trioxide, antimony chloride, and antimony acetate. Among them, antimony trioxide is preferably used from the viewpoint of polycondensation catalytic activity, physical properties of the resulting polyester fiber and cost.

  The antimony compound is characterized by a sufficient polycondensation activity, but has the effect of promoting thermal decomposition in the latter stage of the polycondensation reaction. However, when it is added in a large amount, the amount of carboxyl end groups in the polyester increases, resulting in a fiber with reduced wet heat resistance.

  Since it is necessary to reduce the addition amount of the antimony compound within a range where a sufficient polycondensation reaction rate is exhibited, the content of the antimony compound in the polyester fiber satisfies the formula (1).

The content of the antimony compound in the fiber is preferably 0.8 × 10 ⁻⁴ ≦ [Sb] ≦ 2.5 × 10 ⁻⁴ among the range defined by the formula (1). When the value is less than the value determined by the formula (1), the polycondensation activity is not exhibited, and the polycondensation reaction time is prolonged, so that the thermal decomposition reaction proceeds, the carboxyl end group concentration is increased, and the heat and moisture resistance is poor. Become.

On the other hand, when the content of the antimony compound in the fiber is larger than the value determined by the formula (1), not only the color tone of the polyester is deteriorated, but also the thermal decomposition reaction is promoted.
The carboxyl end group concentration becomes high and the heat and humidity resistance becomes poor.

It is important that the polyester fiber of the present invention contains a phosphorus compound in addition to the antimony compound. The content of the phosphorus compound in the fiber needs to satisfy the formula (2), and preferably 0.5 × 10 ⁻⁴ ≦ [P] ≦ 10.0 × 10 ⁻⁴ . As the phosphorus compound, phosphoric acid or its ester (mono-, di- and tri-ester) derived from phosphoric acid or its ester is preferable, and specifically, trimethyl phosphate, triethyl phosphate, triphenyl phosphate. And tris-2-hydroxyethyl phosphate and the like.

  The phosphorus compound not only suppresses deterioration of the color tone of the polyester fiber due to the antimony compound, but also has an effect of suppressing thermal decomposition. When the content of the phosphorus compound in the fiber is less than the value determined by the formula (2), these effects become insufficient, and even if the formula (1) is satisfied, the color tone of the fiber is sufficiently improved, It becomes difficult to improve the wet heat resistance. On the other hand, when the content of the phosphorus compound in the fiber is larger than the value determined by the formula (2), the inside of the polyester system becomes acidic during the polycondensation reaction, thereby forming an ether bond as a side reaction product. Not only is the thermal properties inferior, but the strength also decreases.

  In the conductive conjugate fiber of the present invention, by obtaining the content of the antimony compound and the phosphorus compound as appropriate amounts (amounts represented by the formulas (1) to (2)), a fiber having improved moisture and heat resistance can be obtained. Was made.

Further, in the fiber of the present invention, it is preferable that the contents of the antimony compound and the phosphorus compound satisfy the formula (3) at the same time in order to sufficiently exhibit the above effects.
(3) [P] / [Sb] ≧ 0.2
As described above, since the phosphorus compound has an effect of suppressing the deterioration of the color tone of the polyester fiber by the antimony compound and the thermal decomposition action, it is preferable to satisfy the formula (3) indicating the ratio with the antimony compound. .

  That is, in the conductive conjugate fiber of the present invention, it is preferable to add an antimony compound and a phosphorus compound during the polycondensation reaction of the polymer to cause the polycondensation reaction. And in this invention, content in the fiber of these compounds shall satisfy Formula (1)-(2) simultaneously, More preferably, Formula (3) shall be satisfied simultaneously.

  Usually, in order to obtain fibers with low carboxyl end group concentration and excellent heat and moisture resistance, it is necessary to carry out melt polymerization and solid phase polymerization in the polyester polycondensation reaction. Further, by adding a phosphorus compound, it is possible to obtain a polyester excellent in wet heat resistance constituting the conductive conjugate fiber of the present invention having a low carboxyl end group concentration only by melt polymerization.

  The carboxyl end group concentration of the conductive conjugate fiber of the present invention 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 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.

  Further, the conductive composite fiber of the present invention may contain a compound other than the antimony compound and the phosphorus compound. Examples thereof include titanium compounds and cobalt compounds used as polycondensation catalysts.

  As the titanium compound, tetra n-butyl titanate, tetra n-propyl titanate, tetraisopropyl titanate, tetraethyl titanate, etc. are used, and tetra n-butyl titanate is preferable from the viewpoint of polycondensation catalytic activity and physical properties of the resulting fiber. .

  Examples of the cobalt compound include cobalt acetate, cobalt chloride, and cobalt benzoate. Cobalt acetate is preferable from the viewpoint of physical properties of the obtained fiber.

  The content of the antimony compound and phosphorus compound in the conductive composite fiber of the present invention is such that the conductive composite fiber is heated and melted on an aluminum plate and then formed into a molded body having a flat surface by a compression press machine. This is subjected to quantitative analysis using a line measuring device (Model 3270 manufactured by Rigaku Corporation).

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

It is necessary to use polyethylene terephthalate (PET) as the non-conductive component polyester-based resin .

As a copolymerization component, it is PET which copolymerized at least one component among isophthalic acid (IPA), cyclohexanedimethanol (CHDM), and cyclohexanedicarboxylic acid (CHDA) , The copolymerization amount is 5-20 mol%. Of these, 5 to 10 mol% is preferable.

  By making the non-conductive component a PET copolymerized with the above copolymer component, not only the compatibility with the conductive component is improved, but also the reaction temperature during the polycondensation reaction can be lowered. The temperature of the hour can also be lowered. Therefore, since the thermal decomposition reaction of the polymer at the time of polycondensation reaction and spinning can be suppressed, it is possible to obtain a conductive composite fiber having excellent moisture and heat resistance.

  If the copolymerization amount is less than 5 mol%, the melting point does not drop much compared to ordinary PET, so the polycondensation reaction temperature and spinning temperature cannot be lowered, and the effect of improving the heat and moisture resistance tends to be insufficient. When the copolymerization amount exceeds 20 mol%, the amorphous region in the fiber increases, so that not only the operability is deteriorated, but also a structure that is susceptible to hydrolysis reaction, so that the heat-and-moisture resistance performance tends to be lowered. .

Next, the conductive component will be described. As the polyester resin of the conductive component, it is necessary to use PBT, and it is also possible to use a single or copolymerized one.

PBT is a resin with very high crystallinity, so the contained conductive particles are arranged more uniformly, so it has excellent conductivity (low electrical resistance) and uniform conductivity in the length direction. It can be set as the fiber which has.

Further, the conductive component needs to be a copolymerized PBT in which at least one component of IPA, CHDM, and CHDA is copolymerized .

  By using such a copolymerized PBT, compatibility (surface wettability) between the conductive component and the conductive particles can be improved, and the content of the conductive particles can be increased. It can have electrical conductivity. Furthermore, the flexibility of the polymer is improved, the spinning and drawing process can be carried out smoothly, and the arrangement state of the conductive particles can be improved, so that the conductivity is excellent (low electric resistance value) and the length direction. It is possible to obtain a fiber having uniform conductivity.

As a copolymer component, CHDM, CHDA, when using any type of IPA, or both if these in combination plural kinds, copolymerization amount is required to be 5 to 40 mol%, among them 10 to 30 mol % Is preferable. When the copolymerization amount is less than 5 mol%, the effect of improving the compatibility (surface wettability) with the conductive particles as described above, the effect of improving the flexibility of the polymer, and the effect of improving the durability are insufficient. On the other hand, if it exceeds 40 mol%, the polymer itself becomes completely amorphous, so that it is difficult to disperse the conductive particles in the polymer.

  If the copolymerization amount is less than 5 mol%, it is difficult to obtain the effect of improving the compatibility (surface wettability) with the conductive particles, and the effect of increasing the amount of mixed conductive particles and improving the flexibility of the polymer will be small. . On the other hand, if it exceeds 40 mol%, the polymer itself becomes completely amorphous, and thus it is difficult to disperse the conductive particles in the polymer.

  The intrinsic viscosity (IV) of the conductive component is preferably 0.5 to 0.8. When IV is less than 0.5, the fluidity of the polymer is increased and the dispersibility of the conductive particles in the polymer is improved, but the subsequent granulation property is deteriorated, and it is difficult to form a pellet. When IV exceeds 0.8, the fluidity and crystallinity of the polymer deteriorates, the conductivity performance tends to be inferior, and the electric resistance value tends to increase.

  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, and other metals. Compounds. 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 uniformly disperse the conductive particles in the polymer.

  Further, in the conductive component and the non-conductive component, 1,3-propanediol, sebacic acid, dimer acid, dodecanedioic acid, xylylene are included as other copolymerization components as long as the effects of the present invention are not impaired. Glycol, polytetramethylene glycol, polyethylene glycol and the like may be contained. Depending on the purpose, waxes, polyalkylene oxides, various surfactants, organic electrolytes and other dispersants and antioxidants, UV absorbers and other stabilizers, matting agents, colorants, pigments, fluidity An improving agent and other additives can also be added.

  In the present invention, at least one of the conductive component and the non-conductive component is a polymer containing a specific amount of the antimony compound and the phosphorus compound as described above, whereby the antimony compound and the phosphorus compound in the conductive composite fiber. The content of can satisfy the above formulas (1) to (2) and further the formula (3). In particular, the non-conductive component is a polymer containing a specific amount of the antimony compound and the phosphorus compound as described above, so that the conductive component is less likely to crack even after repeated wet heat treatment, and the conductive particles are missing or dropped off. And conductive fibers having heat-and-moisture resistance not found in conventional fibers can be obtained.

  In addition, even if the conductive component has 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, it is preferable that both the conductive component and the non-conductive component are polyesters containing a specific amount of an antimony compound and a phosphorus compound.

  Furthermore, the polyester resin of these conductive component and non-conductive component preferably has a carboxyl end group concentration of 25 geq / t or less, particularly 20 geq / t or less, and more preferably 18 geq / t or less.

  When the carboxyl end group concentration of the conductive component and the non-conductive component is higher than 25 geq / t, the carboxyl end group concentration of the conductive composite fiber is also increased, and the heat and moisture resistance tends to be poor.

  The carboxyl end group concentration of the conductive component and the non-conductive component is 1/10 specified after dissolving 0.1 g of the conductive component or non-conductive component in 10 ml of benzyl alcohol and adding 10 ml of chloroform to this solution. It is determined by titration with a potassium hydroxide benzyl alcohol solution.

  Thus, as a method of lowering the carboxyl end group concentration of the conductive component and the non-conductive component, in addition to the method of adding the antimony compound and the phosphorus compound at the polycondensation reaction, the method of adding the end-capping agent at the time of spinning Alternatively, a method of adjusting and changing the polymerization conditions (amount of catalyst, temperature, etc.) at the time of melt polymerization may be employed.

  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.

  That is, in the conductive conjugate fiber of the present invention, either one of the conductive component and the nonconductive component is a polyester having a low carboxyl end group concentration by containing an antimony compound and a phosphorus compound, and the other component is It is good also as polyester which made the carboxyl end group density | concentration low by adding the above terminal blockers or adjusting polymerization conditions.

  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.

Next, the manufacturing method of the electroconductive composite fiber of this invention is demonstrated.
The conductive component and non-conductive component polyester can be obtained by carrying out a conventional polycondensation reaction. Then, an antimony compound and a phosphorus compound are included during the polycondensation reaction of at least one polyester of the conductive component and the nonconductive component, and melt polymerization is performed to obtain a polyester component having a reduced carboxyl end group concentration. 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.

  In addition, as a method for obtaining the conductive component, there are a method of adding conductive particles in the polymerization stage of the base polymer, and a method of adding conductive particles to the polymer by post-processing and melt-kneading, but the polymer used Some of them are difficult to add at the polymerization stage, and therefore, a melt-kneading method is preferable in post-processing.

  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 can be suitably used in various applications such as repeated wet heat treatments, is required for antistatic effects, and needs to be repeatedly subjected to wet heat treatments such as sterilization, for clean rooms and medical use. It can be suitably used for apparel applications such as work uniforms, 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 making a cylindrical 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. Content of antimony compound, cobalt compound and phosphorus compound in conductive composite fiber Measured by the above method.
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
PBT (substantially butylene terephthalate) with an intrinsic viscosity of 0.75 (measured at a temperature of 20 ° C. using an equimolar mixture of phenol and ethane tetrachloride as a solvent) and a carboxyl end group concentration of 25 geq / t as a conductive component 100% by mole of repeating unit) and carbon black having an average particle diameter of 0.2 μm (amount to be 27% by mass in the conductive component) as the conductive particles are melt-kneaded, and then converted into chips by a conventional method. Sex ingredient.
As a non-conductive component, a slurry of terephthalic acid and ethylene glycol having a molar ratio of 1 / 1.6 is continuously added to an esterification reaction can in which bis (β-hydroxyethyl) terephthalate and its low polymer (BHET) are present. The esterification reaction was conducted under the conditions of a temperature of 250 ° C., a pressure of 0.05 kg / cm ² and a residence time of 8 hours, and BHET having an esterification reaction rate of 95% was continuously obtained. 50 kg of this BHET is transferred to a polymerization tank and heated to 265 ° C., and antimony trioxide as a catalyst is 1.0 × 10 ⁻⁴ mol per 1 mol of the acid component constituting the polyester, and triethyl phosphate as the phosphorus compound constitutes the polyester. 0.5 × 10 ⁻⁴ mol was added to 1 mol of the acid component. After that, the pressure was gradually reduced, and finally a polycondensation reaction (melt polymerization only) was carried out at 265 ° C. under a reduced pressure of 0.1 toll for 3.5 hours. The intrinsic viscosity (equal mass mixture of phenol and ethane tetrachloride was used as a solvent, PET (measured at a temperature of 20 ° C.) of 0.64 and a carboxyl end group concentration of 9.0 geq / t was obtained and chipped by a conventional method. This was made into the nonelectroconductive component.
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 a conductive component, carbon black having an average particle size of 0.2 μm was added to a copolymerized polybutylene terephthalate (copolymerized PBT) obtained by copolymerizing 15 mol% of isophthalic acid with an intrinsic viscosity of 0.65 and a carboxyl end group concentration of 24 geq / t. A melt-kneaded product was used to make a chip by a conventional method to obtain a conductive component.
In addition, a slurry of terephthalic acid and ethylene glycol having a molar ratio of 1 / 1.6 is continuously added to an esterification reaction vessel in which bis (β-hydroxyethyl) terephthalate and its low polymer (BHET) are present as non-conductive components. The esterification reaction was conducted under the conditions of a temperature of 250 ° C., a pressure of 0.05 kg / cm ² and a residence time of 8 hours, and BHET having an esterification reaction rate of 95% was continuously obtained. 50 kg of this BHET was transferred to a polymerization tank, and a slurry of isophthalic acid and ethylene glycol was added so that isophthalic acid would be 8 mol%, then heated to 265 ° C., and antimony trioxide as a catalyst was an acid component 1 constituting the polyester 1.0 × 10 ⁻⁴ mol per mol, and 0.5 × 10 ⁻⁴ mol of triethyl phosphate as a phosphorus compound was added to 1 mol of the acid component constituting the polyester. After that, the pressure was gradually reduced, and finally the polycondensation reaction (melt polymerization only) was carried out at 265 ° C under a reduced pressure of 0.1 toll for 4.0 hours. The intrinsic viscosity (equal mass mixture of phenol and ethane tetrachloride was used as the solvent, An isophthalic acid 8 mol% copolymerized PET (measured at a temperature of 20 ° C.) of 0.64 and a carboxyl end group concentration of 11.0 geq / t was obtained and chipped by a conventional method. A conductive conjugate fiber was obtained in the same manner as in Example 1 except that this was a non-conductive component.

Examples 3-7
Conductive component, the type of copolymerization component in the non-conductive component and the amount of copolymerization were changed as shown in Table 1, and the same as in Example 2 except that the values shown in Table 1 were combined. A conductive conjugate fiber was obtained.

Example 8
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.

Examples 9-14
The same procedure as in Examples 2 to 7 except that a spinneret designed so that the cross-sectional shape of the single yarn is as shown in FIG. / 2 conductive composite fiber was obtained.

Comparative Example 1
Example 3 except that a spinneret designed so that the cross-sectional shape of the single yarn is a core-sheath type as shown in FIG. 4 is used, and the conductive component is arranged in the core and the non-conductive component is arranged in the sheath. In the same manner as above, a conductive conjugate fiber was obtained.

Comparative Examples 2 and 3
Except having changed the compound addition amount of the nonelectroconductive component into the value of Table 1, it carried out similarly to Example 3 and obtained the electroconductive composite fiber.

  Table 1 shows the measurement results of various values of the conductive conjugate fibers obtained in Examples 1 to 14 and Comparative Examples 1 to 3.

As is clear from Table 1, the conductive composite fibers of Examples 1 to 14 had low electrical resistance values before and after wet heat treatment, low conductivity performance reduction rate, and excellent electrical conductivity performance. Further, 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 a 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 have a high carboxyl end group concentration and do not have heat-and-moisture resistance because the compound addition amount in the conjugate fiber is out of the scope of the present invention. Has a high electrical resistance value, a low strength, a high rate of decrease in conductive performance, and a low strength retention.

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 (3)

A non-conductive component made of polyethylene terephthalate copolymerized with 5 to 20 mol% of at least one component among isophthalic acid, cyclohexanedimethanol and cyclohexanedicarboxylic acid, and at least one component among isophthalic acid, cyclohexanedimethanol and cyclohexanedicarboxylic acid. It is composed of 5 to 40 mol% copolymerized polybutylene terephthalate and is composed of a conductive component containing conductive particles, and has a shape in which at least a part of the conductive component is exposed on the fiber surface. The conductive conjugate fiber contains an antimony compound and a phosphorus compound that satisfy the following formulas (1) to (2) at the same time, and has an electric resistance of 1 × 10 ⁴ Ω. ~1 × 10 ⁷ Ω / cm, conductivity degradation rate after wet heat treatment (121 ° C. in 25 hours) is 20 or less, Moist heat conductive composite fiber characterized by heat treatment (121 ° C. in 25 hours) after the strength retention rate of 70% or more.
(1) 0.5 × 10 ⁻⁴ ≦ [Sb] ≦ 3.0 × 10 ⁻⁴
(2) 0.1 × 10 ⁻⁴ ≦ [P] ≦ 20.0 × 10 ⁻⁴
In addition, [Sb] represents the content of the antimony compound, [P] represents the content of the phosphorus compound,
The unit is “mol / acid component mol”. 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.