JPH03137224A - Electroconductive conjugate fiber and its production - Google Patents

Abstract

PURPOSE:To obtain the subject fiber for clothing able to be stably fabricated having excellent whiteness and imparting electroconductivity to white cloth, etc., in mixing with other fiber by spinning a core component comprising thermoplastic polymer with a specific cuprous iodide powder and a sheath component comprising polyester. CONSTITUTION:A thermoplastic resin having 90-150 deg.C melting point and a cuprous iodide powder having 0.6-1.2mum average particle diameter are used as a core component and polyester having 20-240 deg.C melting point is used as a sheath component, then the two components are simultaneously spun by a conjugate spinning machine at 250-270 deg.C spinning temperature to afford the objective fiber. Besides, for instance, polyethylene, etc., as said resin and polybutylene terephthalate, etc., as said polyester are preferably used.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to conductive fibers suitable for use in clothing, and more specifically conductive core-sheath type composites using a specific cuprous iodide powder. It relates to fibers and their manufacturing methods.

[Conventional technology]

Synthetic fibers, such as polyester fibers and polyamide fibers, have low conductivity and therefore generate static electricity due to friction, attract dust, and cause various problems due to discharge.

To solve this problem, textile products are mixed with conductive fibers such as metal fibers, metal-plated fibers, fibers coated with polymer dope containing conductive substances, and fibers containing carbon black. It is being However, all of these conductive fibers had drawbacks and were not satisfactory.

For example, metal fibers have drawbacks such as reduced conductivity due to refraction during use or processing, difficulty in mixing with other fibers, inter-knitting, or inter-weaving, and exhibiting a color tone unique to metals.

Fibers with metal plating require "plating treatment" -1 smoothness of the fiber surface, which limits the types of fibers that can be applied, increases manufacturing costs, and makes the plating layer easy to peel off during use or processing, resulting in poor durability. It has disadvantages such as low elasticity and metallic color.

Fibers coated with a polymer dope containing a conductive substance also have the same drawbacks as metal-plated fibers in terms of manufacturing cost, peeling, etc.

Furthermore, carbon black-containing fibers exhibit a black color, which impairs their appearance and limits their field of use.

In order to improve the drawbacks of carbon black-containing fibers, research has been carried out on fibers containing white conductive substances, and among them, conductive fibers containing cuprous iodide,
It has a high white skin and excellent physical properties.

However, although such cuprous iodide-containing fibers are certainly white in color compared to carbon black-containing fibers, they still have insufficient white skin compared to fibers from the normal route, and are particularly white. The reality is that its use on light-colored fabrics is still restricted.

Further, it has been difficult to obtain fibers with excellent performance and spinnability from a composition containing cuprous iodide in ordinary polyethylene terephthalate.

[Problem to be solved by the invention]

An object of the present invention is to provide a conductive composite fiber that contains cuprous iodide, has an excellent white skin, and can be stably spun, and a method for producing the same.

[Means to solve the problem]

In the present invention, the core component consists of a thermoplastic polymer with a melting point of 90 to 150°C and cuprous iodide powder with an average particle size of 0.6 to 1.2 μm, and the sheath component has a melting point of 200 to 240°C. It is a conductive composite fiber made of polyester.

The core component of the conductive composite fiber of the present invention consists of cuprous iodide powder and a thermoplastic polymer. The thermoplastic polymer used here must have a melting point in the range of 90 to 150°C. If the melting point is less than 90°C, the thermal stability will be poor and it will not be possible to form a good thread.

If the temperature exceeds 150"C, the viscosity becomes high and spinning is impossible at low temperatures. If the spinning temperature is increased to lower the viscosity, the core component containing cuprous iodide will thermally deteriorate and gas will be generated. However, the core components are mainly polyolefins and polyesters, but some of these may be replaced by copolymers, and thermoplastic polymers with a melting point of 90 to 150°C may also be used. Polymers other than the above may be used depending on the purpose, and two or more of them may be mixed if necessary.As the core component, the fluidity and heat of the core component From the viewpoint of stability, polyolefins are preferred, and polyethylene is particularly preferred.

Further, the cuprous iodide powder has an average particle size of 0.6 to
It is necessary that the thickness is 1.2 μm.

The average grain size of cuprous iodide is 0. If the particle size is less than 6 μm, secondary agglomeration tends to occur, and impurities trapped in the secondary agglomerated particles cannot be easily removed even by washing. Therefore, if the particle size of cuprous iodide is less than 0.6 μm, powder The white skin deteriorates rapidly. Therefore, in order to improve the white skin of the conductive composite fiber containing cuprous iodide powder, it is necessary to use cuprous iodide powder having an average particle size of 0.6 μm or more.

On the other hand, if the average particle size of the cuprous iodide powder becomes too large, the efficiency of particle continuity in the composite fiber will deteriorate;
Especially since it causes a decrease in the conductive performance of the fiber after stretching.
The average particle size of the cuprous iodide powder is 1. It is necessary that the thickness is 2 μm or less.

To mix the polymer in the core component and the cuprous iodide powder, any method can be used as long as it allows good dispersion and mixing. The amount of cuprous iodide to be mixed is 1.0 to 3.0% of the weight of the core component polymer due to the trade-off between electrical conductivity and formability.
4 times is appropriate.

Further, the core component may contain arbitrary additives, such as a coupling agent, a matting agent, a coloring agent, and an oxidation stabilizer, if necessary.

The cross-sectional shape of the core component of the composite fiber of the present invention can be any shape, and the number thereof can be any number greater than or equal to 1.

The area ratio of the core component to the cross section of the fiber can be within a wide range, but is preferably 3 to 50%. If the area ratio of the core component is less than 3%, it is practically difficult to distribute the core polymer in the fiber axis direction and between each hole, and the conductivity tends to decrease. On the other hand, if it exceeds 50%, the fluidity of the core decreases. As a result, the spinning and drawing tension deteriorates, and the strength of the resulting conductive fibers decreases.

The polymer constituting the sheath component of the conductive composite fiber of the present invention is
It needs to be a fiber-forming polymer that can be stably spun, and polyester with a melting point of 200 to 240°C is used. If the melting point of the sheath component is less than 200°C, the mechanical properties tend to deteriorate, while if it exceeds 240°C, the core component will be thermally degraded and gas will be generated, leading to poor spinning and making it impossible to obtain a satisfactory yarn.

A preferable example of the polyester used for the sheath component is polybutylene lenticulate having a melting point of 225°C. In this case, it is sufficient that 80 mol% or more of the repeating units are butylene terephthalate, and a copolymer or mixed polymer containing this as a main component may be used. Further, examples of polyesters having a melting point of 200 to 240°C include polyethylene terephthalate copolymers in which 10 to 20 mol% of the acid component is isophthalic acid.

The intrinsic viscosity of the polyester is preferably 0.5 or more in order to ensure the mechanical properties and conductivity of the resulting fiber. If the intrinsic viscosity is less than 0.5, it is necessary to set a high draw ratio in order to obtain a normal yarn quality, which is not preferable because the conductivity tends to decrease. The higher the upper limit of the intrinsic viscosity, the easier the mechanical properties will be exhibited, but polymers that require a spinning temperature of over 270°C are undesirable because their spinning properties deteriorate.

Note that the intrinsic viscosity of polyester is a value calculated from the solution viscosity measured at 35° C. in an orthochlorophenol solution.

The polyester used in the sheath component of the present invention may contain arbitrary additives, such as a quenching agent, a coloring agent, an oxidation stabilizer, etc., as necessary.

The present invention also provides a method for producing conductive composite fibers, in which the core component and sheath component are spun at 200 to 240°C using a composite spinning machine.

The cuprous iodide powder used for the core component is sufficiently stable at temperatures below 300°C in an N2 atmosphere, and is stable at temperatures below 300°C even when dispersed in the thermoplastic polymer of the core component. Surprisingly, when spinning composite fibers, conductive fibers with good white discoloration, conductivity, and spinnability can only be obtained by spinning at a spinning temperature of 250 to 270°C.

The reason for this is unknown, but it may be due to changes in the viscosity and thermal stability of the core component polymer.If the spinning temperature is below 250℃, the sheath polymer becomes weak yarn, resulting in a decrease in spinnability. The mechanical properties of the conductive fiber deteriorate. on the other hand,
When the temperature exceeds 270° C., the spinning properties are greatly reduced, and the electrical conductivity and mechanical properties are also reduced. That is, it is preferable to perform spinning at as low a temperature as possible.

More preferably, as a composite spinning machine, equipment having a conduit part that can individually set the temperature of the core/sheath polymer immediately before the spin block is used, and the core component is heated to a conduit temperature of 180 to 250.
It is preferable that the sheath component is transported at 250 to 290°C, then guided into a spin block and spun at 250 to 270°C. If the temperature of the conduit on the core component side is less than 180°C or more than 250°C, the spinning properties will be reduced.

Also, if the conduit temperature on the sheath component side is less than 250'C or 2
If the temperature exceeds 90° C., the mechanical properties of the yarn deteriorate due to the sheath component being below the weak yarn limit or decreasing the intrinsic viscosity, which is not preferable.

Further, in the present invention, the fibers obtained by spinning may be directly drawn, or may be drawn using a separate drawing machine, but direct drawing is preferable from the viewpoint of electrical conductivity.

〔Example〕

Hereinafter, the conductive composite fiber of the present invention will be described in further detail with reference to Examples.

In addition, the conditions for measuring the electrical resistance value of the conductive composite fiber in the examples are 20° C., 130% RH1], and KV DC voltage.

In addition, the average particle size of cuprous iodide was calculated by centrifugal sedimentation light transmission method using a centrifugal particle size measuring device based on the obtained centrifugal sedimentation curve.

That is, based on the centrifugal sedimentation curve, the particle size at which the sedimented particle weight corresponds to 50% by weight with respect to the total particle weight is read from the cumulative weight particle size distribution curve that expresses the sedimented particle weight with respect to the particle diameter and the total particle weight. The average particle size was defined as 0.

Note that CAPA-500 (manufactured by Horiba, Ltd.) was used as the measuring device, and the above operations were processed by a microcomputer.

The measurement conditions are as follows.

Dispersion medium; sodium hexametaphosphate 0. 1% by weight
Aqueous solution rotation speed: 1500 rpm Measurement range: O to 2.0 μm The strength and elongation of the drawn yarn were determined according to JIS L1023, and the white skin (L value) was measured as follows.

That is, a Σ80 color measuring machine manufactured by Nippon Heavy Industries, Ltd. is used and the reflected light of the sample is measured by comparing it with a standard plate.

Examples 1 to 5 and Comparative Examples 1 to 4 The core component was a composition obtained by sufficiently heating and mixing 100 parts by weight of polyethylene and 300 parts by weight of cuprous iodide powder in a kneader, and the melting point was 225 ° C. Polybutylene terephthalate was used as the sheath component and melt-spun. That is, using a spinning machine with a conduit part whose temperature can be set individually just before the spin block and a concentric circular core-sheath type pack, spinning was carried out under the conduit temperature and spinning temperature conditions shown in Table 1, and at a speed of 1,200 m/min. I rolled it up. This material was stretched 2.8 times at 10.5°C and heat-set at 200°C to obtain a composite fiber.

Table 1 shows the complete winding rate after spinning and stretching.

The area ratio of the core and sheath in the cross section of this composite fiber is 1
:6, and the fiber composition was 30 denier/3 filaments.

Table 1 shows the mechanical properties, white skin, and cross-sectional electrical resistance values of the composite fibers obtained.

Comparative Example 5 A composite fiber was obtained in exactly the same manner as in Example 1, except that polyethylene terephthalate (melting point: 265° C.) was used as the polyester of the sheath component.

Table 1 shows various physical properties of the obtained composite fiber.

Example 6 A composite fiber was obtained in exactly the same manner as in Example 1, except that a polyethylene terephthalate copolymer (melting point: 228° C.) in which 12 mol% of the acid component was isophthalic acid was used as the polyester.

1 2 Table 1 shows various physical properties of the obtained composite fiber.

Comparative Example 6 A composite fiber was obtained in exactly the same manner as in Example 1, except that a polyethylene terephthalate copolymer (melting point: 195° C.) in which 25 mol% of the acid component was isophthalic acid was used as the polyester of the sheath component.

Table 1 shows various physical properties of the obtained composite fiber.

(The following is a blank space) 3 [Effects of the Invention] The conductive composite fiber of the present invention has excellent resistance to whitening and can be stably spun, so it can be mixed, interlaced or interwoven with other fibers such as polyester and polyamide to produce white or light colored fibers. Conductivity can be imparted to the fabric.

Claims (2)

[Claims] (1) The core component consists of a thermoplastic polymer with a melting point of 90 to 150°C and cuprous iodide powder with an average particle size of 0.6 to 1.2 μm, and the sheath component is a polyester with a melting point of 200 to 240°C. A conductive composite fiber made of (2) A thermoplastic polymer with a melting point of 90 to 150°C and cuprous iodide powder with an average particle size of 0.6 to 1.2 μm are used as the core component, and a polyester with a melting point of 200 to 240°C is used as the sheath component. A method for producing conductive composite fibers, which comprises spinning at a spinning temperature of 250 to 270°C using a composite spinning machine.