JPS63235525A - Electrically conductive conjugated yarn - Google Patents

Abstract

PURPOSE:To obtain the titled novel yarn having excellent antistatic properties and high whiteness degree free from metal wearability, industrially and readily producible, comprising an electrically conductive component having specific sectional shape, by combining a non-electrically conductive component with the electrically conductive component. CONSTITUTION:A non-electrically conductive component comprising a fiber- forming polymer and having >=10<7>OMEGA.cm specific resistance and an electrically conductive component comprising a thermoplastic polymer and inorganic electrically conductive particles and having <10<7>OMEGA.cm specific resistance are used to give the aimed yarn which has a sectional shape of the electrically conductive component consisting of a thick part 1 covered with the non-electrically conductive component 4 and a thin part 2 connected to the thick part 1 and reaching the surface of fiber and has <=1.5mum exposed width of the electrically conductive component to the surface of fiber. Polyamide is used as the non-electrically conductive component and polyethylene is preferably used as the thermoplastic polymer constituting the electrically conductive component.

Description

DETAILED DESCRIPTION OF THE INVENTION (Industrial Application Field) The present invention relates to a novel conductive composite fiber. Specifically, the present invention relates to conductive composite fibers that are not abrasive to metals and are easy to manufacture industrially.

(Prior Art) It is well known that fibers, especially hydrophobic fibers such as polyester, polyamide, polyacrylonitrile, polyolefin, etc., generate a significant amount of static electricity due to friction, etc., and the electrostatic voltage often exceeds 10 KV, causing various problems. ing. For this reason, many proposals have been made regarding antistatic properties (imparting antistatic properties).

One method is to mix metal fibers with chargeable fibers, but the antistatic properties deteriorate due to breakage due to bending during processing and reuse, and mixing, interweaving, and interweaving with other fibers is difficult. However, it has drawbacks such as its unique metallic luster which lowers the quality of the product.

In addition, fibers plated with metal or fibers coated with conductive substances have many drawbacks, such as extremely high production costs, often peeling off due to bending or friction during processing or use, and poor durability. have

Furthermore, fibers in which conductive particles such as carbon black or metal powder are dispersed throughout a thermoplastic polymer suffer from a decrease in spinnability, strength, and elongation when the conductive particles are dispersed to the extent that they impart conductivity. It is extremely difficult to obtain something that can be put to practical use.

In order to overcome this drawback, Japanese Patent Publication No. 52-81450 discloses a fiber that is a side-by-side or core-sheath type composite of a thermoplastic polymer in which conductive particles such as carbon black or metal powder are dispersed and an FJm-forming polymer. Special Public Showa 5B-4
This method has been proposed in Japanese Patent Publication No. 4579, Japanese Patent Publication No. 57-25647-8, etc. However, composite fibers in which a conductive component containing conductive particles is completely wrapped in a non-conductive polymer have the drawback that dielectric breakdown of the sheath part that causes corona discharge is difficult to occur, and the antistatic properties are poor. 1 In addition, composite fibers with a conductive component as a sheath or composite fibers in which a conductive component and a non-conductive polymer are bonded side-by-side have corona discharge properties, that is, antistatic properties, because the conductive component is exposed on the fiber surface. However, the black or gray color of carbon black and inorganic conductive particles stands out, degrading the quality of products made by mixing these composite m-fibers. It also has the disadvantage of being highly abrasive and causing damage to the other party due to friction.

Several proposals have been made to solve these problems. In order to improve the antistatic properties of a core-sheath type composite yarn having a conductive component as a core, for example, Japanese Patent Application Laid-Open No. 60-224
No. 818 discloses a fiber in which metal particles or inorganic particles having a metal coating are dispersed in the sheath component, and Japanese Patent Application Laid-Open No. 1986-
Japanese Patent No. 110920 proposes a fiber whose sheath component has a minimum thickness of 8 μm or less. In addition, in order to reduce the metal abrasion of side-by-side type composite fibers in which SS components are exposed on the surface of W4 fibers, for example, Japanese Patent Application No. 59-2548
No. 49 discloses a fiber that uses a soluble polymer as a sheath component and can expose a conductive component by dissolving and removing it after being made into a product.
No. 126 discloses that the degree of exposure of the conductive component to the fiber surface is 8.
0% or less fibers have been proposed. Each of these fibers has excellent antistatic properties and is designed to prevent metal wear during the processing process, but producing these fibers requires special raw materials and complicated equipment. Therefore, it is necessary to set extremely delicate manufacturing conditions.

(Problems to be Solved by the Invention) The object of the present invention is to provide a novel highly conductive composite with no abrasiveness, excellent antistatic properties, and which can be easily manufactured in an industrial fishing industry. Our goal is to provide la pongee.

(Means for Solving the Problems) The object of the present invention is to combine a non-conductive component made of a fiber-forming polymer with a specific resistance of 107 Ω*cm or more, and a thermoplastic polymer and an inorganic conductive particle with a specific resistance of 107 Ω*cm. In a composite fiber with a conductive component of less than cm, the cross-sectional shape of the conductive component is a thick part wrapped in a non-conductive component, and a thin part that connects to the thick part and reaches the fiber surface. Consisting of
In addition, the exposed width of the conductive component on the fiber surface is at most 1.5 μm.
This is achieved by a conductive composite fiber characterized by:

As the inorganic conductive particles used in the present invention, any type of particles can be used as long as the specific resistance in powder form is about 10 4 Ω·cm or less. Not only metal oxides with high white discoloration and particles with metal oxide coatings, but also carbon black, metal powders (such as silver, nickel, copper, iron, or alloys thereof), copper sulfide, silver iodide, zinc sulfide, and sulfide. Metal compounds such as cadmium may also be used.

Metal oxide particles include tin oxide, zinc oxide, copper oxide,
Examples include particles of cuprous oxide, indium oxide, zirconium oxide, and tungsten oxide. Many metal oxides are semiconductors that are close to insulators and often do not exhibit sufficient electrical conductivity for the purpose of the present invention. However, for example, if an appropriate second component (impurity) is added to the metal oxide,
The conductivity can be strengthened by adding 0% or less, especially 25% or less, and a material having sufficient conductivity for the purpose of the present invention can be obtained. Such conductivity enhancers include:
Antimony oxide can be used for tin oxide, and metal oxides such as aluminum, potassium, indium, germanium, and tin can be used for zinc oxide.

Furthermore, particles in which a conductive film of the above metal oxide or metal compound is formed on the surface of non-conductive inorganic particles such as titanium oxide, zinc oxide, magnesium oxide, tin oxide, iron oxide, silicon oxide, or aluminum oxide are also used. .

Regarding the conductivity of the conductive particles, the specific resistance in powder form is 104Ω・
It is preferably about 102 Ω·cm or less, particularly about 10 2 Ω·cm or less, and most preferably about 10 1 Ω·cm 2 or less. actually 1
02Ω・cm to 10−2Ω・cm can be obtained,
Although it can be suitably applied to the purpose of the present invention, it is even better! Those of i-character are more preferable. The specific resistance (volume resistivity) of the powder is determined by filling an insulating cylinder with a diameter of 1 cm with 5 g of the sample, applying a pressure of 200 kg from the top with a piston, and applying a DC voltage (for example, 0.001 to 1000 Vi) (current of 1 mA or less). ) to measure.

Further, the conductive particles must have a sufficiently small particle size. Although it is not impossible to use particles with an average particle size of 1 to 2 μm, those with an average particle size of 1 μm or less, particularly 0.5 μm or less, and most preferably 0.8 μm or less are used.

The mixing ratio of the conductive particles of the conductive component varies depending on the type of particles, conductivity, particle size, ability to form interlocking particles, and the properties and crystallinity of the binder polymer to be mixed, but is usually 10 to 8.
6% (within the weight range, often 20 to 80
It is about %.

The thermoplastic polymer that is mixed with the inorganic conductive particles to form the conductive component is not particularly limited and can be selected arbitrarily. Examples include plastic polymers.It is preferable to use plastic polymers that form fibers from the viewpoint of spinnability, but even those with poor spinnability can be used as long as a fiber-forming polymer is used as the non-conductive component. Composite fibers with good spinnability can be obtained.Among such polymers, polymers with a crystallinity of 60% or more that have poor affinity with fiber-forming non-conductive polymers are particularly suitable. Examples of such polymers include polyethylene, polypropylene, polyoxymethylene, polyethylene oxide and its derivatives (for example, polyethylene oxide/PET block copolymers), polycaprolactone, polycaprolactone, etc. Among these polymers, polyethylene, polypropylene, and polyoxymethylene are particularly preferred. suitable.

The specific resistance (volume resistivity) of the conductive polymer is 107Ω・c
It is necessary that the resistance is 10 Ω·cm or less, preferably 10 4 Ω·cm or less, and particularly preferably 10 2 Ω·cm 2 or less.

The conductive polymer may further contain a dispersant (e.g. waxes, etc.).
Polyalkylene oxides, various surfactants, organic electrolytes, etc.), colorants, pigments, stabilizers (antioxidants, ultraviolet absorbers, etc.), fluidity improvers, and other additives can be added.

As the composite mw, coa fiber-forming polymer, any material that can be spun can be used. Among these, polyamides such as nylon 6, nylon 66, nylon 12, and nylon 610, polyesters such as polyethylene terephthalate, polyethylene oxybenzoate, and polyethylene terephthalate, polyacrylonitrile, and copolymers and modified products of these polymers are particularly suitable. Additives such as matting agents, pigments, coloring agents, stabilizers, antistatic agents (polyalkylene oxides, various surfactants, etc.) can be added to the law-forming polymer. However, it is not preferable to contain such a large amount of inorganic particles that it may cause metal wear. The specific resistance of such a fiber-forming polymer is preferably 10 7 Ω·cm or more.

In the composite fiber of the present invention, the composite ratio (cross-sectional area occupancy) of the conductive polymer is preferably 3 to 40%, more preferably 4%.
~20%, most preferably 5-15 scratches. If the composite ratio is small, the conductivity will decrease, and therefore the antistatic property will be poor. In addition, if the amount is too large, the quality of the thread will be poor and the metal abrasion resistance will also increase.

Width where the conductive component is exposed on the fiber surface (for example, d in Figure 1)
2) is at most 1.5 μm or less, preferably at most 1.5 μm.
2 μm, most preferably at most 1.0 μm. If the width of the conductive component exposed on the fiber surface is large, gold, lr1* wear is likely to occur.

The cross section (outline) of the composite fiber of the present invention may be circular or non-circular and is not particularly limited, but a circular cross section is preferred.

In the composite fiber of the present invention, the shape of the conductive component is important. As shown in Figures 1 to 6, the shape of the conductive component has a thick part at the head and a thin part corresponding to the tail, with the tip of the tail becoming thinner and forming a fiber surface. A shape resembling an exposed tadpole is preferred.

The head can take any shape such as circular, elliptical, triangular, or square, but it is preferable that its thickness (for example, dl in FIG. 1) be 5 μm or more. It is preferable that the head and tail can be clearly distinguished (for example, in FIG. 1), but it is also preferable that the head and tail are not clearly distinguished (for example, in FIGS. 2 and 5). The tail may be a thin part continuous to the head, or it may have a straight shape, but a curved tail is more preferable in order to narrow the exposed width. Also, the width may be the same from the part connected to the head to the tip of the tail (
(Figure 1), gradually becoming thinner (Figures 2, 4, and 5), and things that become thinner or thicker (Figures 2, 4, and 5).
(Fig. 6) is preferable for controlling the exposure width narrowly. On the other hand, if the shape (Fig. 10) consists only of a band-like part without a head (thick part), the exclusive performance and even the antistatic performance tend to decrease or become unstable if it is made thinner. If it is made thicker, metal abrasion becomes significant, which is not preferable.

(Function & effect) In this way, the conductive 4-rimer has a head (thick part) and a tail, and only the tip of the tail reaches the fiber periphery1. The reason why the excellent antistatic properties and metal wear resistance, which are the objectives of the present invention, can be achieved is considered to be as follows. In other words, conductivity with a specific resistance of 107Ω・cm or less? It is thought that it is easy for the charge to move in the length direction of the fiber because the reamer is continuous in the head, for example, inside the fiber with a thickness of 6 μm or more. The fibers are stretched, false-twisted,
It will not be damaged even during processing processes such as turning, weaving, weaving, etc. On the other hand, since the tail is thin and continuous and reaches the rugged surrounding area, it is thought that it has the function of discharging the charge held by &l[.

(Example) The present invention will be explained below with reference to Examples. In Example 1, antistatic properties were evaluated by the following method. Ordinary 6 nylon drawn yarn (210 denier 154 filament) is knitted using a circular knitting machine, and conductive composite fibers are knitted at intervals of 1 out of 10 turns to create a circular knitted fabric with a mixing rate of 0.85%. . After removing the spinning oil by scouring, it was thoroughly washed with water, dried at 80°C for 3 hours, and further heated at 25°C at 180°C.
%RH atmosphere for 6 hours. Thereafter, it was rubbed 15 times with a cotton cloth at the same temperature and humidity, and the charged voltage was measured after 10 seconds.

Metal abrasion resistance is 100% on a stainless steel wire with a diameter of 85 μm.
When the thread is run at a speed of m/min (thread tension before contact 4
~5g, contact angle 45°) Evaluation was made based on the cutting time of the stainless steel wire.

For conductivity, 5 single threads of 10 cm length were tied together with metal terminals and conductive adhesive (Fujikura Kasei Dotite D-55).
0), the resistance value was measured by applying a DC voltage of IOV, and the resistivity of the conductive component calculated from the resistance value was evaluated.

Example 1 0 for titanium oxide particles having a tin oxide film on the surface
．． Conductive particles with an average particle size of 0.25 μm obtained by mixing and firing 75% antimony oxide have a specific resistance of 6.3 Ω・c.
It was m. 75 parts (by weight) of this particle and molecular weight go, o
A conductive polymer A1 was prepared by kneading 26 parts of polyethylene (by weight) of 0.0 mm.

Using this conductive polymer and 95% concentrated sulfuric acid, nylon 6 with a relative viscosity of 2.8, it was spun through an orifice with a diameter of 025 mm at a spinning temperature of 280°C so as to have the cross-sectional shape shown in Table 1, and then cooled. It was rolled up at a speed of 800 m/min while being oried. Next, the yarn was drawn at a draw ratio of 2.6 times through a hot roller at 80°C, and further brought into contact with a hot plate at 170°C to obtain drawn yarns Y1 to Y5 of 20 denier/8 filaments. Table 1 shows the electrical conductivity (specific resistance), antistatic properties, and metal abrasion properties of these electrically conductive composite fibers.

Each of the yarns Y1 to Y5 had a specific resistance of the order of 10<-8> or less and exhibited good conductivity. Although Y1 to Y3 and Y5 had good antistatic properties, Y4, in which the conductive polymer was not exposed on the fiber surface, had poor antistatic properties. In addition, metal abrasion resistance is small for Y1 to Y4, but Y5, where the conductive polymer is exposed to the fiber surface with a large width, is significantly inferior to gold Mjl.
) Highly abrasive. Y5 could not be stably manufactured due to large guide wear.

Next, each of Y1 to Y4 was combined with a 2,600 denier 140 filament yarn of nylon 6 and crimped, and one yarn was used for each of the four courses, and the other eight courses were made of nylon only. Rate 0.17
%) was produced. When walking with leather shoes on a carpet obtained indoors at 25° C. and 20% RH, the electrostatic potential of the human body was -2 and OKV for the carpets mixed with fibers Yl to Y8 of the present invention, respectively.

-2,8KVl-1,8K V"iC" was there. On the other hand, a carpet mixed with Y4, which is a core-sheath type composite yarn, had a discharge of t-(ti) when it touched a grounded handle at -4.8KV.For comparison, a carpet made only of nylon The electrical charge on the human body is -9.2KV, and the electric discharge shock when touching the grounded handle is severe.
Example 2 Titanium oxide was added as a matting agent to polyethylene terephthalate with a molecular weight of 1,115,000 as a non-conductive polymer.
Using a polymer blended at 65% and using the same Ali used in Example 1 as the conductive polymer, it was composited side-by-side in the spinneret so as to have the cross-sectional shape shown in FIG. Spun from an 8 mm orifice, cooled and oiled, then wound at a speed of 1000 m/min, then stretched to 8.1 times using a heated roll at 86°C, and wound while heat-setting with a plate heater at 160°C. , conductive filaments Y6 to Y9 were obtained.

The performance of these filaments was as shown in Table 2.

BRIEF DESCRIPTION OF THE DRAWINGS FIGS. 1 to 6 are schematic diagrams showing cross sections of the fibers of the present invention. No. 71 is a schematic diagram showing a cross section of a core-sheath type composite tin fiber, and FIGS. 8 to 10 are cross-sectional views of a known side-by-side type diagonal #i fiber. In the figure, (1)...thick part of the conductive component,

Claims (6)

[Claims] (1) Specific resistance made of fiber-forming polymer is 10^7Ω
・In a composite fiber consisting of a non-conductive component with a diameter of cm or more and a conductive component with a specific resistance of less than 10^7 Ω cm made of a thermoplastic polymer and inorganic conductive particles, the cross-sectional shape of the conductive component is non-conductive. It consists of a thick part surrounded by a conductive component and a thin part that connects to the thick part and reaches the fiber surface, and the exposed width of the conductive component to the fiber surface is at most 1.5 μm. Characteristic conductive composite fiber. (2) The shape of the conductive component in the fiber cross section is tadpole-shaped with a head and a tail, and the thickness of the head is 5 μm.
The fiber according to claim 1, which is the above. (3) Composite ratio (cross-sectional area occupancy) of conductive components is 3 to 40
% of the fiber according to claim 1. (4) The polymer forming the conductive component is polyethylene,
The fiber according to claim 1, which is polypropylene or polyoxymethylene. (5) Fiber-forming polymer is nylon 6, nylon 66
The fiber according to claim 1, which is a polyamide such as , nylon 12, nylon 610, or a polyester such as polyethylene terephthalate, polyethylene oxybenzoate, or polybutylene terephthalate. (6) The exposed width of the conductive component on the fiber surface is at most 1.2 μm
The fiber according to claim 1, which is