JPH0672325B2 - Conductive composite fiber - Google Patents

Description

TECHNICAL FIELD The present invention relates to a conductive conjugate fiber. For more details,
The present invention relates to a conductive composite fiber having high conductivity and capable of concealing coloring of a core component in appearance.

(Prior Art) Demands for conductive fibers exist in various fields such as clothing and industrial.

The conductive fiber is used as a fiber for clothes or mixed with a carpet to remove static electricity, that is, to suppress friction withstand voltage. Further, it is used for the purpose of shielding radio waves in the electronics industry using computers and the like and its peripheral fields.

However, the conductive fibers currently in use have a drawback in that the use thereof is limited because the black color of the substance responsible for the conductivity is visible as the color of the fibers. Various methods have been devised to cover such drawbacks. For example, there is a method of preventing the black conductive fiber from being exposed on the surface by devising a weaving method, but it is not satisfactory.

In addition, various measures have been taken to reduce the coloring by devising the conductive fiber itself. For example, in the core-sheath conductive fiber, there is a method of adding white inorganic particles to the sheath component to suppress the black color of the core component, but its effect is not sufficient because the mixing rate of the inorganic particles to be added is limited, There is a problem that the strength is significantly reduced due to the mixing of the inorganic particles. Also, a method of increasing the thickness of the sheath component has been taken, but the problem of inevitably increasing the fiber diameter occurs.

In addition, there are many methods of using a substance other than carbon black as a substance having conductivity. For example, a method of using copper iodide, tin oxide or the like, or a method of coating the surface of tin oxide with titanium oxide can be used. However, this method has a drawback that the cost is high and the obtained conductivity is not so high.

Furthermore, as a post-treatment, a method has been found in which a metal-containing solution is brought into contact with the surface of the non-conductive fiber to coat or chemically bond a conductive substance. Certainly, this method gives a light-colored and highly conductive fiber,
However, whitening is still difficult, and there is a limit to the fibers that can be used, such as being applicable only to polymers having a specific functional group.

(Problems to be Solved by the Invention) An object of the present invention is to solve the above problems and to provide a fiber which has high conductivity and suppresses the coloring of the fiber in a manner unprecedented, and enables the development of arbitrary coloring or gloss. And

(Means for Solving the Problems) In order to achieve the above object, the present invention has the following configuration.

(1) In a conductive composite fiber whose core component is a polymer containing a conductive substance, a sheath component is formed of a heterogeneous polymer or a laminated body of a plurality of film-like constituent elements laminated via a hollow layer, and A conductive composite fiber, wherein right side surfaces of a laminate constituting a sheath component are bonded.

(2) The volume resistivity value of the conductive substance contained in the core component is
10 ⁶ Ωcm or less, and its content is 10% with respect to the core polymer.
The conductive composite fiber according to claim 1, which is at least wt%.

(3) The conductive composite fiber according to claim 1 or 2, wherein the conductive substance is carbon black.

(4) The electroconductive conjugate fiber according to (1), wherein the number of laminated layers is 10 or more.

(5) The conductive composite fiber according to (1), wherein the different polymers constituting the laminate are polyester and polyamide.

(6) The difference in the refractive index of the different kinds of polymers forming the laminate is 0.
The electrically conductive composite fiber according to (1) or (5), which is 03 or more.

Hereinafter, the present invention will be described in detail.

The greatest feature of the composite conductive fiber in the present invention is that a sheath component is formed by a laminate of a large number of film-like constituents via different kinds of polymers or hollow layers, and the right side surface of the laminate constituting the sheath component is It's in the process of joining.

That is, in the fiber cross section, the core component is multiply surrounded by different kinds of polymers or hollow layers to form a sheath.

In other words, a large number of concentric film-shaped components, which are formed through different kinds of polymers having different refractive indices or hollow layers, are laminated in a concentric circle, and the reflection efficiency with respect to the incident light to the fiber is significantly increased. That is, the coloring of the core component is suppressed and the reflected lights of light from various layers interfere with each other to exhibit a desirable gloss characteristic.

The term "laminate" as used in the present invention means a cross-section in which a film-shaped component composed of the component A is superposed with a film-shaped component composed of a different type of B or a hollow layer.

The right-angled side surface is a side surface perpendicular to the longitudinal direction of the film-shaped component, that is, a side surface perpendicular to the joining surface of the film-shaped component.

In FIGS. 1, 2, and 3, 1 and 2 are film-like constituent elements, 3 is a portion where the right side surfaces of the laminate are joined, and 4 is a core component.

1 shows the case where there is one laminated body, FIG. 2 shows the case where there are two laminated bodies, and FIG. 3 shows the case where there are four laminated bodies.

In FIGS. 4, 5, and 6, 1 is a film-like constituent element, 3 is a portion where right-angled side faces of the laminate are joined, 4 is a core component, and 5 is a hollow portion.

In the present invention, when the right side surfaces of the laminate forming the sheath component are all bonded, when the number of layers is large and the thickness of the film-shaped component is thin, the polymers of both components are mixed in at this part at the time of bonding. Happens. Since this part connects each layer and functions as a pillar, the cross-sectional shape of the fiber is less likely to collapse, and excellent integrity and favorable mechanical performance can be imparted.

In the present invention, the hiding effect of the colored core component is more remarkable as the number of interfaces of the sheath component, that is, the number of layers, is more remarkable, and preferably 10
The number of layers is not less than 20 layers, more preferably not less than 20 layers, and in some cases even more than 1000 layers does not matter. Further, the number of sheets may be different depending on each laminated body. When the number of layers is large, the thickness of the film-like component usually becomes thin, and the bonding between the film-like components becomes stronger and more preferable depending on the combination of the polymers.

The ratio of the composite components in the present invention is A / B = 99/1 by weight ratio.
˜1 / 99, preferably A / B = 95/5 to 5/95.

In the present invention, the sheath component is usually composed of two or more kinds of polymers, and when the hollow layer is included, it is composed of one or more kinds of polymers.

The hollow layer in the present invention has, for example, a shape as shown in FIGS. 4 to 6, which is obtained by removing at least one component of the sheath component composed of two or more kinds of polymers. . Any method can be used for removal, and methods such as dissolution with a solvent, thermal decomposition, radiolysis, hydrolysis, acid, alkali decomposition, and chemical reduction are used. Even when such a hollow layer is present, the bonded portion on the right side surface of the laminate supports the remaining film-like constituent element, and makes it difficult for the hollow portion to be crushed.

As the polymer constituting the sheath component in the present invention, polyester, polyamide, polyacrylonitrile, polyethylene, polypropylene, polystyrene, polymethylmethacrylate, polyurethane, polyvinyl chloride, acetate, etc. There is no particular limitation as long as it is a polymer used.

Further, since two or more kinds of polymers are simultaneously spun, one component can usually be used alone by tying together polymers which are difficult to form into fibers. As an example of this, polycarbonate,
Examples thereof include polyethylene naphthalate. Two or more kinds of polymers are selected from these polymers according to the purpose and application. Further, there is no problem even if a blend of the above polymers is used as one component of the sheath component.

A combination of polyester and polyamide is preferable from the viewpoints of price, versatility, and ease of setting spinning conditions.

The conductive composite fiber of the present invention not only masks the coloring of the core component, but when a novel luster such as pearl luster is to be provided together, the polymer constituting the sheath may be transparent. desirable. Further, when the film-shaped constituent element of the sheath component is composed of two or more kinds of polymers, it is preferable that the difference in the refractive index is large. The larger the relative ratio of the refractive indexes, the more preferable. Specifically, 0.03 or more is preferable, and 0.1 or more is more preferable. As a specific example of the combination, polyvinyl chloride, polystyrene, polycarbonate or the like can be selected according to the purpose with respect to polyethylene or polymethyl methacrylate or polypropylene.

Further, in order to enhance diffuse reflection of light, it is no problem to add fine particles of titanium oxide, barium sulfate, calcium carbonate or the like to at least one of the sheath components. Calcium carbonate is more preferred for increasing the gloss of the fiber.

The conductive substance in the present invention has high conductivity, so that the conductivity of the entire fiber is manifested and finally the generation of static electricity is suppressed. Usually, the substance is used for spinning after being premixed with a polymer constituting a core component for forming a filament. Therefore, the shape of the substance is preferably a differential powder or a whisker in order to disperse it uniformly in the polymer, and its maximum diameter or maximum length is preferably 5 μm or less, more preferably 1 μm or less, and further 0.3 μm or less. More preferable.

Further, in order to finally remove static electricity in the state of the thread or cloth, the volume resistivity of the substance is 10 ⁶ Ωcm or less,
It is preferably 10 ⁴ Ωcm or less. If this condition is satisfied, all kinds of substances can be used, and conductive metal oxides such as carbon black, various metal powders, tin oxide, zinc oxide, copper oxide, indium oxide, zirconium oxide, and tungsten oxide can be used. it can. In addition, the metal oxide doped with a conductivity enhancer, particles obtained by applying the metal oxide coating to non-conductive particles, and conversely various non-conductive substances on the surface of the conductive particles. For this reason, those coated can also be used. Further, a metal compound such as copper sulfide, cuprous iodide, zinc sulfide, cadmium sulfide, or a conductive intercalation compound can be used. In addition, organic conductive compounds such as polyacetylene, polypyrrole, polythiophene, and polyaniline may be used. Among these, carbon black is preferable from the viewpoint of conductivity and price. The present invention is a great feature in that it is possible to achieve whitening, which was impossible with a conductive fiber using ordinary carbon black.

The ratio of the conductive material to the polymer constituting the core is
If the amount is too small, the conductivity as a whole is lowered, and if the amount is too large, uniform mixing with the polymer becomes difficult and stable spinning is hindered. Therefore, 5% to 50% is preferable, and 10% to 40% is more preferable by weight. A known method can be used as a method for mixing the polymer and the conductive substance, and for example, blending using an ect-strider or a kneader is possible.

The polymer constituting the core component in the present invention is not particularly limited, polyester, polyamide, polyolefin, polyvinyl-based, polyether, polyurethane and the like can be used, from the ease of mixing with the substance having the above conductivity. Polyolefin-based polymers such as polyethylene and polyamide-based polymers such as nylon 6 and nylon 66 are more preferable.

In the present invention, the ratio of the core component and the sheath component is not particularly limited. However, if the core ratio is excessively increased to obtain high conductivity, it becomes difficult to conceal and the yarn strength also decreases, which is not preferable. Usually, the weight ratio of core: sheath = 3: 97-
30:70 is preferable, and 5:95 to 20:80 is more preferable.

The yarn diameter and the cross-sectional shape of the core component of the conductive composite fiber in the present invention are not particularly limited. Further, this conductive composite fiber can be used as a so-called processed yarn in which a fineness mix, a heat shrinkage mix, or a mixture with another fiber, and further false twisted to impart stretchability and bulkiness.

In addition, the electroconductive conjugate fiber of the present invention can be used in the form of a woven fabric, a knitted fabric, a non-woven fabric or the like or a composite body thereof.

The present invention does not ask any means for producing such a fiber, but an example of preferably producing such a fiber will be described below.

The fiber of the present invention is basically obtained by an ordinary core-sheath composite spinning method. Here, it is characterized in that the shape of the discharge nozzle of the sheath component surrounding the core component is a deformed discharge nozzle represented by C type.

In order to produce a fiber having the cross section of FIG.
According to the method described in Japanese Examined Patent Publication No. 1048/60, a multilayer bonded composite polymer stream in which two polymers having different properties are alternately and repeatedly bonded in a spinning pack is prepared. This corresponds to the above-mentioned laminated body and constitutes the sheath component of the target fiber. Next, the laminate is stretched in the longitudinal direction of the film component, and discharged from the C-type nozzle mouthpiece so that the right-angled side faces are joined. At this time, the core component is simultaneously discharged from the central portion of the C-shaped nozzle, and both are merged, so that the fiber of FIG. 1 is finally obtained.

Further, as shown in FIG. 2, when the number of laminated bodies constituting the sheath is two, the two laminated bodies are joined at a right angle side face by using a joining plate, and the joined laminated body is further attached to the film component. It can be obtained by stretching in the longitudinal direction, discharging this from the C-shaped nozzle mouthpiece at the same time as the core component as described above, and joining both.

Further, in order to obtain a fiber having the cross section of FIG. 3, four laminates are bonded at right angles to each other in the same manner as described above, and the bonded laminate is stretched in the longitudinal direction of the film component, which is then stretched. It can be obtained by discharging from the C-type nozzle mouthpiece at the same time as the above-mentioned core component and joining them.

Further, in order to prepare a fiber having a hollow layer as a part of the laminated body as shown in FIGS.
It can be obtained from the fibers shown in FIGS. 5, 5 and 6 by treating and removing one component of the sheath component with a drug having solubility or degradability only for the polymer.

INDUSTRIAL APPLICABILITY The composite conductive fiber of the present invention can be used for the purpose of removing static electricity or shielding radio waves in a wide field for clothing or non-clothing.

(Example) Example 1 16 rows of fluid mixers in which six fluid alternating arrangement elements of the same type as those described in Japanese Patent Publication No. 60-1048 are vertically connected, and two rows of fluid mixers are discharged to the lower part thereof. Using a bonding plate for bonding the fluid and an expanding plate for expanding the fluid, a laminate of a large number of film-like constituent elements of polyethylene terephthalate and nylon is made, and a C-shaped die is formed so that the laminate serves as a sheath component. It was ejected. At this time, nylon containing 30% of carbon black as the core component was discharged at the same time as the sheath component. The spinning conditions at this time were: temperature 280 ° C, take-up speed 1500 m / min, filament number 1
6, the core-sheath ratio = 20/80, and the film-like component ratio of the sheath component was 50:50.

Continuously, stretching speed 300m / min, hot plate temperature 120
Stretching was carried out at a temperature of 2.8 ° C. and a draw ratio of 2.8, and then the yarn was combined into a 48-denier 16-filament stretched yarn.

The cross-sectional shape of the obtained fiber had the structure shown in FIG. That is, it is a cross-section in which carbon black-containing nylon is used as a core component, and polyethylene terephthalate and nylon are concentrically arranged alternately around 50 to 65 pairs repeatedly, and the two right-angled side faces are joined to form a ring. Met.

When the specific resistance of the fiber was measured by a conventional method, it was 4 × 10 ² Ωc.
The color of the fiber was m, and the color of the fiber was concealing the black color of the core component, and was a white color comparable to ordinary polyethylene terephthalate.

Example 2 A fiber having a cross section shown in FIG. 1 was obtained in exactly the same manner as in Example 1 except that the combination of polymers constituting the sheath was polystyrene and polyethylene terephthalate. Next, when the fibers were impregnated in a bath of trichlene and polystyrene was removed, fibers having the same shape as the cross section shown in FIG. 4 were obtained.

When the specific resistance of the fiber was measured by a conventional method, it was 6 × 10 ² Ωc
m, and the fiber masked the black color of the immersion component, and showed an appearance similar to that of ordinary polyethylene terephthalate.

Example 3 16 rows of fluid mixers in which six fluid alternating arrangement elements of the same type as those described in JP-B-60-1048 are vertically connected, and a fluid discharged from the two rows of fluid mixers is connected to the lower portion thereof. A laminate of multiple film-like components of 1.49 refractive index polyethylene and 1.59 polystyrene was made using a tie plate, as well as an expanding plate that stretches the fluid. Then, the two laminated bodies were bonded to each other at a right angle side by using a bonding plate, and the bonded laminated body was stretched in the longitudinal direction of the film component. Next, core-sheath composite spinning was performed in the same manner as in Example 1 so that the stretched bonded laminate became the sheath component. Also in this example, a C-type mouthpiece was used for discharging, and nylon containing 30% of carbon black was used as a core component. At this time, the spinning conditions were a temperature of 270 ° C., a take-up speed of 1500 m / min, a filament number of 6, a core-sheath ratio of 10/90, and a film-like constituent ratio of 50:50 in the sheath component.
And Subsequently, the drawing speed was 300 m / min, the hot plate temperature was 120 ° C, and the drawing ratio was 2.8.
Denier, 16 filament drawn yarn was used.

The fiber has the cross-sectional structure of FIG. 2 and the appearance is
In addition to the sheath component hiding the black of the core component, the sheath component consists of a laminate of two types of thin layers of polymers with a refractive index difference of 0.1 or more, and because it is a transparent polymer, it exhibits a luster close to pearlescent, The conductive fiber has an unprecedented appearance.

When the specific resistance of the fiber was measured by a conventional method, it was 3 × 10 ^3.
It was Ωcm and showed excellent conductivity.

Comparative Example A composite spinning was carried out at a core-sheath ratio of 6:94 using the nylon containing 30% of carbon black used in Example 1 as a core component and polyethylene terephthalate containing 6% of titanium oxide as a sheath component. Subsequently, the fiber was subjected to the same drawing treatment as in Example 1 to obtain a multifilament having 50 denier and 18 filaments. The specific resistance of the fiber was 3 × 10 ⁴ Ωcm, and the color of the fiber was gray even though a large amount of titanium oxide was mixed in and the core component ratio was suppressed.

(Effects of the Invention) The electroconductive conjugate fiber of the present invention has high electroconductivity, and can suppress its coloring, and enable the development of arbitrary coloring or gloss.

In particular, as the number of layers of the laminate as the sheath component increases, the hiding effect can be increased. Therefore, for example, it can be used as a white conductive fiber for clothing and is excellent in versatility.

[Brief description of drawings]

FIG. 1, FIG. 2, FIG. 3, FIG. 4, FIG. 5, and FIG. 6 are cross-sectional model views showing an example of the conductive composite fiber of the present invention. 1,2: Film-like component 3: Part where the right side surfaces of the laminate are joined 4: Core component, 5: Hollow part

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Claims (6)

[Claims] 1. A conductive composite fiber comprising a polymer containing a conductive substance as a core component, wherein a sheath component is formed of a heterogeneous polymer or a laminated body of a plurality of film-like constituents laminated via a hollow layer, Moreover, the electroconductive conjugate fiber is characterized in that the right-angled side faces of the laminate constituting the sheath component are bonded. 2. The conductive material according to claim 1, wherein the conductive material contained in the core component has a volume resistivity value of 10 ⁶ Ωcm or less, and the content thereof is 10% by weight or more based on the core polymer. Composite fiber. 3. The conductive composite fiber according to claim 1, wherein the conductive substance is carbon black. 4. The conductive composite fiber according to claim 1, wherein the number of laminated layers of the laminated body is 10 or more. 5. The electrically conductive composite fiber according to claim 1, wherein the different polymers constituting the laminate are polyester and polyamide. 6. The electroconductive conjugate fiber according to claim 1, wherein the difference in refractive index between the different kinds of polymers constituting the laminate is 0.03 or more.