JP4859916B2 - Conductive conjugate fiber and method for producing the same - Google Patents

Description

  The present invention relates to a conductive conjugate fiber, in particular, a conductive conjugate fiber in which a conductive layer made of a thermoplastic resin and conductive particles and a protective layer made of polyester are combined. Moreover, it is related with the suitable manufacturing method of such an electroconductive composite fiber.

  Conventionally, various conductive fibers are known. Among them, a conductive layer made of a thermoplastic resin composition containing conductive particles such as carbon black, and a thermoplastic resin containing no conductive particles. Conductive conjugate fibers having a protective layer made of are widely used. This is obtained by composite spinning a thermoplastic resin composition containing conductive particles and a thermoplastic resin containing no conductive particles, and the conductive layer is formed in the fiber length direction on the surface or inside of the fiber. It is arranged to be continuous. Such conductive conjugate fibers are described in, for example, Patent Documents 1 to 4 and the like.

  In order to obtain sufficient conductive performance by a conductive layer made of a thermoplastic resin composition containing conductive particles, it is necessary to mix a large amount of conductive particles in the thermoplastic resin composition. However, when a large amount of conductive particles are blended, there is a problem that spinnability and stretchability are rapidly deteriorated. If stretched forcibly, even if the conductive layer is cut or not cut in the fiber, the structure of the conductive carbon black is destroyed, and even in actual use, the conductive fiber is slightly damaged. When the external force is applied, the conductive layer may be easily cut and the conductive performance may be lost. Therefore, when producing a conductive conjugate fiber, there are many cases where it cannot always be sufficiently stretched, and there is a possibility that the yarn physical properties such as elongation and boiling water shrinkage will change over time. In particular, when producing conductive composite fibers that are required to have a certain degree of elongation or boiling water shrinkage for use as a blended yarn, the change in physical properties over time is more conspicuous. there were.

  Patent Document 5 describes a highly shrinkable polyester fiber made of a polyester resin composition obtained by blending polyethylene terephthalate and polyethylene naphthalate. It is described that the highly shrinkable polyester fiber exhibits a high shrinkage rate and shrinkage stress, and is excellent in storage stability at a high temperature of 70 ° C. or higher. However, Patent Document 5 only describes high-shrinkable fibers composed only of the polyester resin composition, and describes fibers composed of a resin composition containing a large amount of conductive particles. Neither is it described for composite fibers.

JP 57-29611 A JP 58-132119 A JP-A-9-279416 JP 2003-278031 A JP 2001-288618 A

  The present invention has been made in order to solve the above problems, and has excellent conductivity that lasts for a long period of time, and also has an elongation of a certain level or more during transportation and storage. An object of the present invention is to provide a conductive conjugate fiber having a small change in mechanical properties such as boiling water shrinkage with time. Moreover, it aims at providing the manufacturing method of such an electroconductive composite fiber.

  The above-mentioned problems include a conductive layer (A) comprising 60 to 80% by weight of a thermoplastic resin and 20 to 40% by weight of conductive particles, 50 to 95% by weight of polyethylene terephthalate and 5 to 50% by weight of polyethylene-2,6-naphthalate. This is solved by providing a conductive composite fiber characterized in that the protective layer (B) is composed of a composite layer and the elongation (DE) is 100 to 350%.

At this time, it is preferable that the thermoplastic resin constituting the conductive layer (A) is polybutylene terephthalate or polyamide. It is also preferable that the weight ratio (A / B) of the conductive layer (A) and the protective layer (B) is 5/95 to 50/50. It is also preferable that the boiling water shrinkage (Wsr) is 20 to 60%. Further, when stored under conditions of 60 ° C. and 80% RH, the elongation (DE ₆₀ ) after 60 days from spinning is 1.3 times or less of the elongation (DE ₁ ) after 1 day from spinning. The boiling water shrinkage (Wsr ₆₀ ) 60 days after spinning is 0.3 times or more of the boiling water shrinkage (Wsr ₁ ) ₁ day after spinning, and the boiling water shrinkage (Wsr ₆₀ ) 60 days after spinning. Is preferably 10% or more. Moreover, the carpet using the fiber which extended | stretched such an electroconductive composite fiber is a suitable embodiment of this invention.

In addition, the above-mentioned problems include a resin composition (a) comprising 60 to 80% by weight of a thermoplastic resin and 20 to 40% by weight of conductive particles, 50 to 95% by weight of polyethylene terephthalate and 5 to 50 of polyethylene-2,6-naphthalate. A method for producing a conductive composite fiber comprising composite spinning of a resin composition (b) comprising% by weight, wherein the molten resin composition (a) and the molten resin composition (b) are merged to form composite spinning. The problem can also be solved by providing a method for producing a conductive conjugate fiber which is melted and discharged from a die and wound at a speed of 1500 to 3000 m / min. At this time, the following (1) to (5) are preferably performed in that order, and the following (2) and (3) are preferably performed before the discharge yarn first contacts the roller or guide.
(1) The molten resin composition (a) and the molten resin composition (b) are joined and melted and discharged from the composite spinneret. (2) The discharged molten resin composition is once less than the glass transition point. Cool to temperature (3) Next, run in the heating device and stretch heat treatment (4) Then apply oil agent (5) Wind up at a speed of 1500 to 3000 m / min

  The conductive conjugate fiber of the present invention has excellent electrical conductivity that lasts for a long period of time, and has a certain degree of elongation, but also has mechanical properties such as elongation and boiling water shrinkage during transportation and storage. The change with time is small. Therefore, the physical properties of fibers are stable even in long-distance transportation such as international transportation, and long-term storage, and subsequent process, for example, mixed fiber, twisted yarn, weaving, knitting, etc. A homogeneous product can be obtained. Moreover, according to the manufacturing method of this invention, it is easy to obtain such an electroconductive composite fiber.

It is the graph which showed the result of having measured with time about elongation (DE), boiling water shrinkage (Wsr), and electrical conductivity about the composite fiber obtained in Example 1. FIG. It is the graph which showed the result of having measured with time about elongation (DE), boiling water shrinkage (Wsr), and electrical conductivity about the composite fiber obtained in Example 2. FIG. It is the graph which showed the result of having measured over time about the degree of elongation (DE), boiling water contraction rate (Wsr), and conductive performance about the composite fiber obtained in Example 3. FIG. It is the graph which showed the result of having measured over time about the degree of elongation (DE), boiling water shrinkage (Wsr), and conductive performance about the composite fiber obtained in Example 4. FIG. It is the graph which showed the result of having measured with time about elongation (DE), boiling water shrinkage (Wsr), and electrical conductivity about the composite fiber obtained by comparative example 1. FIG.

  The conductive conjugate fiber of the present invention comprises a conductive layer (A) comprising 60 to 80% by weight of a thermoplastic resin and 20 to 40% by weight of conductive particles, 50 to 95% by weight of polyethylene terephthalate and polyethylene-2,6-naphthalate. The protective layer (B) comprising 5 to 50% by weight is composited.

  The thermoplastic resin contained in the conductive layer (A) is not particularly limited as long as it is a fiber-forming thermoplastic resin. Usually, thermoplastic polyester and thermoplastic polyamide are preferably used. Moreover, it is preferable from the point of practical durability that melting | fusing point of resin which comprises a conductive layer (A) is 200 degreeC or more. The melting point is more preferably 210 ° C or higher and 250 ° C or lower.

  Examples of the thermoplastic polyester used in the conductive layer (A) include fragrances such as terephthalic acid, isophthalic acid, naphthalene-2,6-dicarboxylic acid, 4,4′-dicarboxydiphenyl, and 5-sodium sulfoisophthalic acid. Dicarboxylic acid components such as aliphatic dicarboxylic acids such as azelaic acid and sebacic acid, and aliphatic diols such as ethylene glycol, diethylene glycol, propylene glycol, 1,4-butanediol, polyethylene glycol, and polytetramethylene glycol; Mention may be made of fiber-forming polyesters formed using a diol component such as an aromatic diol such as an ethylene oxide adduct of bisphenol A or bisphenol S; an alicyclic diol such as cyclohexanedimethanol. Among them, polyesters containing 80 mol% or more, particularly 90 mol% or more of ethylene terephthalate units or butylene terephthalate units, which are general-purpose polyesters, are preferable.

  In particular, polybutylene terephthalate, that is, a polyester containing 80 mol% or more of butylene terephthalate units is preferable because the conductive particles can be easily kneaded and easily crystallized, so that high conductive performance can be obtained. Polyethylene terephthalate can also be used, but if a large amount of conductive particles are added, the spinnability during melt spinning will decrease, and it is conceivable to use copolymerized polyethylene terephthalate to improve spinnability. When polymerized polyethylene terephthalate is used, the crystallinity is generally lowered and the conductive performance is lowered. From the above, polybutylene terephthalate, which is a polyester that easily forms crystals, is particularly excellent. Polyethylene-2,6-naphthalate may be blended with polybutylene terephthalate.

  As the thermoplastic polyamide used in the conductive layer (A), polyhexamethylene adipate (nylon-6, 6), polyε-caprolactam (nylon-6) or a copolymer thereof is preferably used. Such a thermoplastic polyamide is preferably used like polybutylene terephthalate because it is easy to knead a large amount of conductive particles.

  The conductive particles contained in the conductive layer (A) are not particularly limited as long as they are conductive particles, and conductive carbon black, conductive metal oxide particles, metal particles, and the like can be used. Of these, conductive carbon black is preferably employed from the viewpoint of the balance between conductive performance and cost. The particle diameter of the conductive particles is not particularly limited as long as it can be spun, but an average particle diameter of 0.01 to 1 μm is preferable.

The conductive carbon black used in the present invention preferably has a specific electric resistance of 10 ⁻³ to 10 ³ Ω · cm. When carbon black is completely dispersed in particles, the conductivity is generally poor, and when a chain structure called a structure is formed, the conductivity is improved and the carbon black is called conductive carbon black. Become something. Therefore, when conducting a polymer with conductive carbon black, it is important to disperse the carbon black without destroying the structure. Therefore, there are many cases where a sufficient stretching operation cannot be performed, and the fibers tend to have insufficient dimensional stability.

Further, since the conductive metal oxide particles are not black unlike carbon black, it is also possible to impart conductivity to white fibers, which is useful in terms of design. The conductive metal oxide particles used in the present invention refer to white or colorless metal oxide fine particles or fine particles in which the metal oxide is coated on the surface with inorganic fine particles as nuclei. Many metal oxides are semiconductors close to insulators and often do not exhibit sufficient conductivity. However, as a conductivity enhancer (doping agent) for metal oxides, antimony oxide for tin oxide, aluminum, potassium, etc. for zinc oxide are known. For example, the specific resistance of tin oxide having an average particle size of 0.1 μm is about 10 ³ Ω · cm, but the specific resistance of a solid body of antimony oxide and tin oxide is 1 to 10 Ω · cm, and the conductivity is enhanced. ing. From the standpoint of overall performance, it is necessary that the ratio of antimony oxide in the solid volume is 0.01 to 0.10 (weight ratio). When the coating amount of antimony oxide is small, the conductivity is insufficient, and conversely, when it is large, it moves away from the target white color direction. As the conductive particles used in the present invention, the coated zinc oxide and tin oxide described above are excellent in conductivity, whiteness, and the like, but metal oxides other than these can also be used.

  In the present invention, one kind of conductive particles or a mixture of two or more kinds can be used. At this time, conductive carbon black and conductive metal oxide particles may be used in combination. Furthermore, metal particles or the like may be used. Moreover, you may mix | blend various additives in the range which does not inhibit the effect of this invention.

  The conductive layer (A) of the present invention comprises 60 to 80% by weight of a thermoplastic resin and 20 to 40% by weight of conductive particles. When the content of the conductive particles is less than 20% by weight, the conductivity may be insufficient. The content of the conductive particles is preferably 23% by weight or more, and at this time, the content of the thermoplastic resin is 77% by weight or less. On the other hand, if the content of the conductive particles exceeds 40% by weight, spinnability and stretchability may be deteriorated. The content of the conductive particles is preferably 33% by weight or less, and at this time, the content of the thermoplastic resin is 67% by weight or more.

  The protective layer (B) of the present invention comprises 50 to 95% by weight of polyethylene terephthalate and 5 to 50% by weight of polyethylene-2,6-naphthalate. When the protective layer (B) is composed mainly of polyethylene terephthalate and blended with polyethylene-2,6-naphthalate, it is possible to suppress changes in fiber properties after spinning with time. In the case of conductive composite fibers, since the resin composition used for the conductive layer contains a large amount of conductive particles, the contribution of the conductive layer to the mechanical performance of the entire composite fiber is not so large. The mechanical properties of the are particularly important.

  The polyethylene terephthalate used for the protective layer (B) is a polyester containing 80 mol% or more, preferably 90 mol% or more of ethylene terephthalate units. The third component may be copolymerized as long as the object of the present invention is not impaired. Examples of the copolymer component preferably used include acid components such as isophthalic acid, adipic acid, sebacic acid, dodecanedioic acid, dimer acid, sulfoisophthalic acid sodium salt, and tetrabutylphosphonium salt of sulfoisophthalic acid, diethylene glycol, 1,4- Examples include glycol components such as butanediol, 1,6-hexanediol, neopentyl glycol, cyclohexane-1,4-dimethanol, and 2,2-bis [4- (2-hydroxyethoxy) phenyl] propane.

  Polyethylene-2,6-naphthalate used for the protective layer (B) is a polyester containing 80 mol% or more, preferably 90 mol% or more of ethylene-2,6-naphthalate units. The third component may be copolymerized as long as the object of the present invention is not impaired. As the copolymer component preferably used, in addition to terephthalic acid, those described in the description of the polyethylene terephthalate can be used.

  The polyethylene terephthalate or polyethylene-2,6-naphthalate used for the protective layer (B) is spun to contain 0.05 to 10% by weight of inorganic fine particles having an average particle diameter of 0.01 to 1 μm. From the viewpoint of the property or knitting and weaving properties. That is, when the content of the inorganic fine particles is less than 0.05% by weight, loops, fluff, fineness spots and the like are likely to occur in the obtained conductive fiber, and when the content exceeds 10% by weight, the process passability is poor. Cause thread. More preferably, the inorganic fine particles are contained at a ratio of 0.2 to 5% by weight. The method for adding the inorganic fine particles is not particularly limited, and may be added and mixed so that the inorganic fine particles are uniformly mixed in the polyester at any stage from the polymerization of the polyester to immediately before melt spinning. A typical example of such inorganic fine particles is titanium oxide.

  The protective layer (B) is composed of 50 to 95% by weight of polyethylene terephthalate and 5 to 50% by weight of polyethylene-2,6-naphthalate. When the content of polyethylene-2,6-naphthalate is less than 5% by weight, a change with time in fiber properties after spinning cannot be sufficiently suppressed. The content of polyethylene-2,6-naphthalate is preferably 10% by weight or more, and more preferably 15% by weight or more. At this time, the content of polyethylene terephthalate is preferably 90% by weight or less, and more preferably 85% by weight or less. On the other hand, when the content of polyethylene-2,6-naphthalate exceeds 50% by weight, not only the production cost increases, but also the filter pressure becomes high during spinning, making it difficult to produce yarn and the resulting conductivity. The elongation of the composite fiber also decreases. The content of polyethylene-2,6-naphthalate is preferably 40% by weight or less, and more preferably 30% by weight or less. At this time, the content of polyethylene terephthalate is preferably 60% by weight or more, and more preferably 70% by weight or more.

  The conductive conjugate fiber of the present invention comprises a resin composition (a) comprising 60 to 80% by weight of a thermoplastic resin and 20 to 40% by weight of conductive particles, 50 to 95% by weight of polyethylene terephthalate and polyethylene-2,6- The resin composition (b) consisting of 5 to 50% by weight of naphthalate is produced by composite spinning. That is, the molten resin composition (a) and the molten resin composition (b) are merged and melt-discharged from the composite spinneret to produce conductive composite fibers.

  The method for producing a conductive conjugate fiber of the present invention can use a general melt spinning apparatus used for producing a conjugate fiber. At this time, from the viewpoint of dispersibility, the pellet of the resin composition (a) obtained by previously melt-kneading the thermoplastic resin and conductive particles is supplied to the melt spinning apparatus to form the conductive layer (A). preferable. Alternatively, polyethylene terephthalate and polyethylene-2,6-naphthalate may be previously melt-kneaded to obtain pellets of the resin composition (b) and then supplied to the melt spinning apparatus to form the protective layer (B). The protective layer (B) may be formed after the pellets are simultaneously supplied to the melt spinning apparatus to obtain the resin composition (b) in the apparatus.

  The winding speed at this time is preferably 1500 to 3000 m / min. When the take-up speed is less than 1500 m / min, both the elongation and the boiling water shrinkage rate become too large, and the dimensional stability is significantly lowered. The winding speed is more preferably 1800 m / min or more, and even more preferably 2000 m / min or more. On the other hand, when the winding speed exceeds 3000 m / min, yarn breakage may occur during spinning, and both the elongation and the boiling water shrinkage ratio are too small. In particular, when producing a conductive conjugate fiber that is required to have a certain degree of elongation or boiling water shrinkage for use as a blended yarn, it is preferable to reduce the winding speed, and more preferably Is 2600 m / min or less, and more preferably 2400 m / min or less.

When spinning, it may be simply wound after cooling the spun yarn by blowing cold air or the like, but in order to effectively prevent the conductive layer (A) from being cut, It is preferable to adopt a simple spinning method. That is, a method is preferably employed in which the following (1) to (5) are performed in that order, and the following (2) and (3) are performed before the discharge yarn first contacts the roller or guide.
(1) The molten resin composition (a) and the molten resin composition (b) are joined and melted and discharged from the composite spinneret. (2) The discharged molten resin composition is once less than the glass transition point. Cool to temperature (3) Next, run in the heating device and stretch heat treatment (4) Then apply oil agent (5) Wind up at a speed of 1500 to 3000 m / min

  The characteristic feature of the above method is that the melted and discharged composite polyester filament is once cooled and then subjected to a heating and stretching treatment using a heating zone such as a tube heater. It is performed without substantially contacting the surface. By using such a method, the conductive fiber is not forcibly drawn between the rollers or between the guide and the roller, but the draw ratio is automatically adjusted in the zone in the heating apparatus from the discharged molten polymer. Therefore, the conductive layer (A) is not stretched so as to be cut. Moreover, the conductive layer (A) is also properly stretched and crystallized, and the amorphous portion is in a state where molecular motion is possible. As a result, the conductive layer (A) is tensioned. However, the conductive layer (A) has a large room for extending without being cut and does not lose its conductive performance. The heating temperature at the time of heating and stretching is in the temperature range from the glass transition temperature of the resin constituting the resin composition (a) to the melting point and below, and the polyethylene terephthalate which is the main component constituting the resin composition (b) It is preferably in the temperature range above the glass transition temperature and below the melting point.

  As the cooling method of (2) above, the temperature of the cooling air is about 20 to 30 ° C., the humidity of the cooling air is about 20 to 60% RH, and the blowing speed of the cooling air is about 0.4 to 1 m / sec. Thus, high-quality fibers can be obtained without causing fineness spots and performance spots. In addition, it is desirable that the heating zone used in the above (3) has a length of 0.6 m or more and 4 m or less, and that the temperature of the heating zone is in the range of 150 ° C. or more and 220 ° C. or less for uniform and smooth stretching.

  In the conductive conjugate fiber of the present invention thus obtained, the weight ratio (A / B) between the conductive layer (A) and the protective layer (B) is preferably 5/95 to 50/50. When the weight ratio (A / B) is less than 5/95, the conductivity tends to be insufficient, and the conductive layer (A) is likely to be cut. The weight ratio (A / B) is more preferably 10/90 or more, and further preferably 15/85 or more. On the other hand, when the weight ratio (A / B) exceeds 50/50, the strength tends to be insufficient, and the change in fiber properties with time tends to increase. The weight ratio (A / B) is more preferably 40/60 or less, and even more preferably 30/70 or less.

  The elongation (DE) of the conductive conjugate fiber of the present invention is 100 to 350%. If the elongation (DE) is less than 100%, the stretching is too strong and the conductive layer (A) may be cut, and the required elongation or boiling water when used as a blended yarn or the like. Can not have shrinkage. The elongation (DE) is preferably 150% or more, more preferably 180% or more, and even more preferably 200% or more. On the other hand, when the degree of elongation (DE) exceeds 350%, stretch spots are likely to occur when the yarn is stretched with other fibers, and it is easy to cut in subsequent processing steps. The elongation (DE) is preferably 300% or less, and more preferably 250% or less. Here, the elongation (DE) is a value measured according to JIS L1013.

  Moreover, it is preferable that the boiling water shrinkage (Wsr) of the conductive composite fiber of the present invention is 20 to 60%. When the boiling water shrinkage rate (Wsr) is less than 20%, when used as a blended yarn or the like, the workability at the time of processing by combining yarns is lowered. The boiling water shrinkage (Wsr) is more preferably 25% or more, and even more preferably 30% or more. On the other hand, when the boiling water shrinkage rate (Wsr) exceeds 60%, for example, when a woven fabric is used, streaks due to shrinkage spots are generated and the texture is deteriorated. The boiling water shrinkage (Wsr) is more preferably 50% or less, and even more preferably 40% or less. Here, the boiling water shrinkage (Wsr) is a value measured according to JIS L1013.

  Although the conductive conjugate fiber of the present invention has a certain degree of elongation, the change over time of fiber properties such as elongation and boiling water shrinkage during transportation and storage is small. In particular, the change in fiber properties is small even when kept at high temperatures.

Specifically, when stored under conditions of 60 ° C. and 80% RH, the elongation (DE ₆₀ ) 60 days after spinning is 1.3 times or less the elongation (DE ₁ ) 1 day after spinning. And is more preferably 1.2 times or less. Here, the reason for starting from one day after spinning is to cancel the change in the degree of elongation (DE) due to moisture absorption and temperature change, and more accurately grasp the change in fiber properties over time. Usually, the elongation (DE ₆₀ ) is 0.9 times or more the elongation (DE ₁ ).

Also, when stored under conditions of 60 ° C. and 80% RH, the boiling water shrinkage (Wsr ₆₀ ) after 60 days from spinning is 0.3 times or more the boiling water shrinkage (Wsr ₁ ) after 1 day from spinning. It is preferable that it is 0.5 times or more, more preferably 0.7 times or more. Here, the reason for starting one day after spinning is the same reason as in the case of the above elongation. Usually, the boiling water shrinkage (Wsr ₆₀ ) is 1.05 or less of the boiling water shrinkage (Wsr ₁ ). And when it preserve | saves on the conditions of ₆₀ degreeC and 80% RH, it is preferable that the boiling water shrinkage (Wsr60) 60 days after spinning is 10% or more, It is more preferable that it is 15% or more, 20 % Or more is more preferable.

  The conductive conjugate fiber of the present invention is used in various forms and for applications that require various neutralization properties. For example, the conductive multifilament and the nonconductive multifilament of the present invention are mixed, and the conductive multifilament is 1 to 30 so that the conductive multifilament is a side yarn and the nonconductive multifilament is a core yarn. % Yarn length can be mixed and used so as to increase. As the core yarn, a polyester-based multifilament is preferable. The total thickness of the non-conductive multifilament used as the core yarn is preferably in the range of 20 to 120 dtex. In the case of blended yarn, it is common to provide entanglement so that the core yarn and the side yarn are not separated, and after imparting entanglement, the mixed yarn may be twisted.

  Alternatively, a non-conductive multifilament may be used as a core yarn, and the conductive multifilament may be spirally wound around it. The thickness of the core yarn is the same as that of the above-mentioned mixed yarn, and the polyester multifilament is suitable as the core yarn. A multifilament yarn using such conductive fibers is driven into a fabric such as a woven fabric or a knitted fabric as a part of a warp and / or a weft at a rate of 1 to 5 mm to 50 mm. As a result, the resulting woven or knitted fabric has a charge removal performance.

  When the fibers are mixed in this way, a mixed fiber having excellent performance can be obtained by having an appropriate elongation (DE) and boiling water shrinkage (Wsr). And since the change over time of fiber properties over a long period of time, such as during transportation and storage, is small, even in long-distance transportation such as international transportation, fiber properties are stable in long-term storage, For example, it is possible to obtain a homogeneous product with good process passability such as mixed fiber, twisted yarn, weaving, and knitting.

  The woven or knitted fabric obtained as described above is used for applications that require long-term static elimination. For example, as a dust-proof garment worn in a clean room, or a worker or chemical engaged in a chemical plant. It can be used as a work wear for static elimination of workers engaged in workplaces that may explode due to static electricity, such as workers who handle the battery. Furthermore, the conductive fiber of the present invention can be used as a part of a pile of a static elimination carpet and further as a static elimination brush for a copying machine.

  The use in which the conductive conjugate fiber of the present invention is particularly preferably used is a carpet that is liable to generate static electricity. The conductive conjugate fiber of the present invention is suitably used as a static elimination fiber in a carpet. For example, in the case of a nylon carpet, 2 to 10 conductive composite fibers of the present invention are added to an unstretched or semi-stretched nylon multifilament yarn of about 1000 to 10000 dtex and aligned, and the aligned yarn is 2 to 4 times. And the obtained drawn yarn is made into a woven fabric or a knitted fabric, into a cut pile carpet or a loop pile carpet. Since the conductive conjugate fiber of the present invention has an appropriate degree of elongation (DE) and the change in fiber properties with time is small, the process passability in the drawing process is good. Since it often takes time to produce a carpet after producing the conductive conjugate fiber, and it is often transported over a long distance, the conductive conjugate fiber of the present invention is preferably used. In particular, it is suitable for a so-called tufted carpet in which the drawn yarn is pierced into a base fabric as a pile yarn, latex is applied to the back surface to prevent the pile from coming off, and a decorative lining is attached.

  Hereinafter, the present invention will be described in more detail with reference to examples. The test method in this example is as follows.

(1) Change with time of elongation (DE) The elongation (DE) was measured according to JIS L1013. After measuring the elongation (DE ₀ ) immediately after spinning, store under the conditions of 60 ° C. and 80% RH, measure the elongation (DE ₁ ) one day after spinning, and then continue under the above conditions. The sample was stored and measured until about 90 days after a suitable period. Regarding the elongation 60 days after spinning (DE ₆₀ ), when there is no data measured after 60 days, the elongation is linear between the elongation measured before and the elongation measured thereafter. Calculated as changing.

(2) Change with time of boiling water shrinkage (Wsr) The boiling water shrinkage (Wsr) was measured according to JIS L1013. After measuring the boiling water shrinkage (Wsr ₀ ) immediately after spinning, store under conditions of 60 ° C. and 80% RH, measure the boiling water shrinkage (Wsr ₁ ) one day after spinning, and thereafter It was stored below and measured until about 90 days after a suitable period. For boiling water shrinkage 60 days after spinning (Wsr ₆₀ ), when there is no data measured after 60 days, the elongation is linear between the elongation measured before and the elongation measured thereafter. It was calculated as changing to.

(3) Conductive Performance The conductive performance was determined as follows based on the period during which the composite fiber stored under the conditions of 60 ° C. and 80% RH maintains a resistance value of 10 ⁻⁸ Ω / cm or less. The resistance value of the composite fiber was measured by super insulation meters “SM8220” and “SME8350” manufactured by Toa Denpa Kogyo Co., Ltd.
○: The above resistance value is maintained for one year or more after spinning.
Δ: The above resistance value is maintained for 6 months or more and less than 1 year after spinning.
X: The resistance value can be maintained only for less than 6 months after spinning.

Example 1
As a raw material for the conductive layer (A), pellets of a resin composition (a) made of polybutylene terephthalate (PBT) containing 25% by weight of conductive carbon black were used. Further, as a raw material for the protective layer (B), polyethylene-2,6-naphthalate (PEN) pellets with respect to 90 parts by weight of polyethylene terephthalate (PET) pellets containing 3% by weight of titanium oxide having an average particle diameter of 0.4 μm. 10 parts by weight were blended and used. The conductive layer (A) and the protective layer (B) are formed such that the conductive layer (A) made of the resin composition (a) forms a sheath and the protective layer (B) made of the resin composition (b) forms a core. ) And a weight ratio (A / B) of 20/80, composite spinning was performed, and spinning was performed at a spinning temperature of 285 ° C. to obtain a conductive multifilament of 38 dtex / 2f.

  As a spinning method, the melt of the resin composition (a) and the resin composition (b) are joined and melted and discharged from the composite spinneret, and the discharged molten polymer is once cooled to a temperature below the glass transition point. Next, the heat treatment is performed by running in a heating device, followed by applying an oil agent, and winding the material at a speed of 2200 m / min. Before the discharge yarn first contacts the roller or guide. went. As the cooling method, cooling air of 25 ° C. and 60% RH was blown against the fibers directly under the nozzle at a speed of 0.5 m / second. Further, as a stretching heat treatment method, a heating tube having a diameter of 3 cm and a length of 1 m was provided at a position 1.5 m directly under the nozzle, and the inside of the tube was maintained at 180 ° C. The fiberization processability was good and no problem. About the composite fiber obtained in this way, elongation (DE), boiling water shrinkage (Wsr), and electrical conductivity were measured over time. The results are shown in FIG. 1, and the composition and evaluation results of the composite fibers are shown together in Table 1.

Example 2
In Example 1, as the raw material for the protective layer (B), the same polyethylene-2,6-naphthalate as used in Example 1 with respect to 80 parts by weight of the same polyethylene terephthalate pellets used in Example 1 A conductive multifilament was obtained in the same manner as in Example 1 except that 20 parts by weight of pellets were blended and used. The composite fiber thus obtained was evaluated in the same manner as in Example 1. The results and the composition of the composite fiber are shown in FIG.

Example 3
In Example 1, as the raw material for the protective layer (B), the same polyethylene-2,6-naphthalate used in Example 1 with respect to 70 parts by weight of the same polyethylene terephthalate pellets used in Example 1 A conductive multifilament was obtained in the same manner as in Example 1 except that 30 parts by weight of pellets were blended and used. The composite fiber thus obtained was evaluated in the same manner as in Example 1. The results and the composition of the composite fiber are shown in FIG. 3 and Table 1.

Example 4
In Example 1, as the raw material for the protective layer (B), the same polyethylene-2,6-naphthalate as used in Example 1 was used with respect to 50 parts by weight of the same polyethylene terephthalate pellets used in Example 1. A conductive multifilament was obtained in the same manner as in Example 1 except that 50 parts by weight of pellets were blended and used. The composite fiber thus obtained was evaluated in the same manner as in Example 1. The results and the composition of the composite fiber are shown in FIG. 4 and Table 1.

Comparative Example 1
In Example 1, conductive multifilaments were obtained in the same manner as in Example 1 except that only the same polyethylene terephthalate pellets used in Example 1 were used as the raw material for the protective layer (B). The composite fiber thus obtained was evaluated in the same manner as in Example 1. The results and the composition of the composite fiber are shown in FIG.

Example 5
In Example 2, conductive multifilaments were obtained in the same manner as in Example 2 except that the spinning speed was changed from 2200 m / min to 1800 m / min. The composite fiber thus obtained was measured for elongation (DE ₀ ) and boiling water shrinkage (Wsr ₀ ) immediately after spinning, and was measured for conductivity performance over time. The evaluation results are shown in Table 2 together with the configuration of the composite fiber.

Example 6
In Example 2, a conductive multifilament was obtained in the same manner as in Example 2 except that the spinning speed was changed from 2200 m / min to 2900 m / min. The results of evaluating the composite fibers thus obtained in the same manner as in Example 5 are shown in Table 2 together with the configuration of the composite fibers.

Example 7
In Example 2, instead of using polyethylene terephthalate pellets as a raw material for the protective layer (B), modified polyethylene terephthalate pellets containing 8 mol% of isophthalic acid component with respect to the total dicarboxylic acid component were used, and the spinning speed was 2200 m / A conductive multifilament was obtained in the same manner as in Example 2 except that the minute was changed to 2500 m / min. The results of evaluating the composite fibers thus obtained in the same manner as in Example 5 are shown in Table 2 together with the configuration of the composite fibers.

Example 8
In Example 1, as a raw material for the conductive layer (A), pellets of the resin composition (a) made of nylon-6 (NY) containing 35% by weight of conductive carbon black were used, and the protective layer (B) was used. As a raw material, the same polyethylene terephthalate pellets used in Example 1, 85 parts by weight, the same polyethylene-2,6-naphthalate pellets used in Example 1, 15 parts by weight, A conductive multifilament was obtained in the same manner as in Example 1 except that the spinning speed was changed from 2200 m / min to 2500 m / min. The results of evaluating the composite fibers thus obtained in the same manner as in Example 5 are shown in Table 2 together with the configuration of the composite fibers.

Example 9
In Example 1, the spinning speed was changed from 2200 m / min to 2500 m / min, the conductive layer (A) having the same composition as in Example 1 formed the core, and the same protective layer (B) as in Example 1 formed the sheath Thus, a conductive multifilament was obtained in the same manner as in Example 1 except that the composite spinning was performed with the weight ratio (A / B) of the conductive layer (A) to the protective layer (B) being 45/55. It was. The results of evaluating the composite fibers thus obtained in the same manner as in Example 5 are shown in Table 2 together with the configuration of the composite fibers.

Example 10
In Example 1, the spinning speed was changed from 2200 m / min to 2500 m / min, the conductive layer (A) having the same composition as in Example 1 formed an island, and the protective layer (B) having the same composition as in Example 1 was Except that a composite spinning was performed with a weight ratio (A / B) of the conductive layer (A) to the protective layer (B) of 20/80 so as to form a sea-island type composite fiber having four islands. Obtained a conductive multifilament in the same manner as in Example 1. The results of evaluating the composite fibers thus obtained in the same manner as in Example 5 are shown in Table 2 together with the configuration of the composite fibers.

Comparative Example 2
In Example 1, as the raw material for the protective layer (B), the same polyethylene-2,6-naphthalate as used in Example 1 with respect to 97 parts by weight of the same polyethylene terephthalate pellets used in Example 1 Conductive multifilaments were obtained in the same manner as in Example 1 except that 3 parts by weight of the pellets were mixed and used, and the spinning speed was changed from 2200 m / min to 2500 m / min. The results of evaluating the composite fibers thus obtained in the same manner as in Example 5 are shown in Table 2 together with the configuration of the composite fibers.

Comparative Example 3
In Example 1, as the raw material for the protective layer (B), the same polyethylene-2,6-naphthalate as used in Example 1 with respect to 40 parts by weight of the same polyethylene terephthalate pellets used in Example 1 A conductive multifilament was obtained in the same manner as in Example 1 except that 60 parts by weight of the pellets were mixed and used, and the spinning speed was changed from 2200 m / min to 2500 m / min. The results of evaluating the composite fibers thus obtained in the same manner as in Example 5 are shown in Table 2 together with the configuration of the composite fibers.

Comparative Example 4
In Example 1, only the same polyethylene terephthalate pellets used in Example 1 were used as the raw material for the protective layer (B), and the spinning speed was changed from 2200 m / min to 2900 m / min. A conductive multifilament was obtained in the same manner. The results of evaluating the composite fibers thus obtained in the same manner as in Example 5 are shown in Table 2 together with the configuration of the composite fibers.

  As can be seen from Tables 1 and 2, the resin composition (b) constituting the protective layer (B) is composed of 50 to 95% by weight of polyethylene terephthalate and 5 to 50% by weight of polyethylene-2,6-naphthalate. Further, the change with time in the elongation (DE), boiling water shrinkage (Wsr), and conductive performance of the conductive conjugate fiber is small (Examples 1 to 10). On the other hand, when the content of polyethylene-2,6-naphthalate in the resin composition (b) constituting the protective layer (B) is less than 5% by weight, the elongation (DE) of the conductive conjugate fiber In addition, the boiling water shrinkage (Wsr) and the change with time of the conductive performance increase (Comparative Examples 1, 2 and 4). That is, the effect of adding polyethylene-2,6-naphthalate to the resin composition (b) constituting the protective layer (B) is clear.

  The conductive multifilament yarn (38 dtex / 2f) obtained in Example 1 and the 3500 dtex unstretched multifilament yarn made of nylon-6,6 are drawn together and stretched 2.6 times to draw the drawn multifilament. Yarn was produced. Moreover, the base fabric was manufactured using the electroconductive multifilament yarn obtained in Example 1 as one component. The stretched multifilament yarn was pierced into the base fabric as a pile yarn, a synthetic rubber latex was applied to the back surface, and a decorative lining was further applied to produce a tufted carpet. In this production process, particularly the stretching process, no breakage of the conductive conjugate fiber was observed, and no trouble was caused in the production process due to the conductive conjugate fiber. Even if the obtained carpet was laid on the floor surface of a dry room in winter and walked repeatedly on the floor, no static electricity was generated. Moreover, there was no discomfort due to static electricity even when touching the carpet.

Claims (10)

  Conductive layer (A) comprising 60 to 80% by weight of thermoplastic resin and 20 to 40% by weight of conductive particles, protective layer comprising 50 to 95% by weight of polyethylene terephthalate and 5 to 50% by weight of polyethylene-2,6-naphthalate Conductive conjugate fiber characterized in that (B) is composited and the degree of elongation (DE) is 100 to 350%.   The conductive conjugate fiber according to claim 1, wherein the thermoplastic resin constituting the conductive layer (A) is polybutylene terephthalate or polyamide.   The conductive conjugate fiber according to claim 1 or 2, wherein the weight ratio (A / B) of the conductive layer (A) and the protective layer (B) is 5/95 to 50/50.   The conductive conjugate fiber according to any one of claims 1 to 3, wherein the boiling water shrinkage (Wsr) is 20 to 60%. 2. When stored under conditions of 60 ° C. and 80% RH, the elongation (DE ₆₀ ) after 60 days from spinning is 1.3 times or less of the elongation (DE ₁ ) after 1 day from spinning. The conductive conjugate fiber according to any one of -4. When stored under conditions of 60 ° C. and 80% RH, the boiling water shrinkage (Wsr ₆₀ ) ₆₀ days after spinning is 0.3 times or more the boiling water shrinkage (Wsr ₁ ) 1 day after spinning. Item 6. The conductive conjugate fiber according to any one of Items 1 to 5. The conductive conjugate fiber according to any one of claims 1 to 6, wherein the boiling water shrinkage (Wsr ₆₀ ) after 60 days from spinning is 10% or more when stored under conditions of 60 ° C and 80% RH.   A carpet in which a fiber obtained by stretching the conductive conjugate fiber according to claim 1 is used.   Resin composition (a) comprising 60 to 80% by weight of thermoplastic resin and 20 to 40% by weight of conductive particles, resin comprising 50 to 95% by weight of polyethylene terephthalate and 5 to 50% by weight of polyethylene-2,6-naphthalate A method for producing a conductive composite fiber comprising composite spinning with a composition (b), wherein the molten resin composition (a) and the molten resin composition (b) are merged and melted and discharged from a composite spinneret. Winding at a speed of 1500 to 3000 m / min, a method for producing a conductive conjugate fiber. The following (1) to (5) are performed in that order, and the following (2) and (3) are performed before the discharge yarn first contacts the roller or guide. For producing functional composite fiber:
(1) The molten resin composition (a) and the molten resin composition (b) are joined and melted and discharged from the composite spinneret. (2) The discharged molten resin composition is once less than the glass transition point. Cool to temperature (3) Next, run inside the heating device and stretch heat-treat (4) Then apply oil agent (5) Wind up at a speed of 1500 to 3000 m / min.

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