JPS6250569B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to conductive fibers, particularly novel conductive composite fibers containing cuprous iodide as a conductive substance.

Synthetic fibers such as polyester fibers and polyamide fibers have low conductivity, so static electricity is generated due to friction. When cloth made of such synthetic fibers is used, it is observed that it is charged with a high potential of several tens of KV, and various problems occur due to the adhesion of dust and discharge.

In order to solve this problem, it is known to mix conductive fibers into textile products, and conductive fibers include metal fibers, metal-plated fibers, fibers coated with polymer dope containing conductive substances, Fibers containing carbon black have been proposed.

However, all of these conventional conductive fibers had serious drawbacks and were not satisfactory. For example, metal fibers do not have bending recovery properties, so their conductive performance decreases when bent during use or processing, they are not easy to mix with other fibers, inter-knit, or inter-weave, and furthermore, they have a color tone unique to metals. It has many drawbacks such as: Metal-plated fibers require a uniform and continuous plating layer to be formed on the fiber surface, which requires smoothness on the fiber surface, which greatly limits the types of fibers that can be applied. It has many disadvantages such as extremely high manufacturing costs as it must be applied precisely, the plating layer tends to peel off during use or processing and has low durability, and it also exhibits a color characteristic of metal. ing. Fibers coated with a polymer dope containing a conductive substance also have the same drawbacks as the above-mentioned metal-plated fibers in terms of manufacturing cost, peeling, and the like. Furthermore, carbon black-containing fibers are colored carbon black, and when mixed with synthetic fibers, the appearance is significantly impaired, which has the fatal disadvantage of limiting the field of use.

The inventor of the present invention, as a result of intensive study in an attempt to provide a conductive fiber free of the above-mentioned drawbacks, focused on using cuprous iodide as a conductive substance, and found that polyethylene terephthalate and cuprous iodide were blended together. Attempts were made to manufacture composite fibers using terephthalate, but in order to impart conductivity, it was necessary to incorporate a considerable amount of cuprous iodide, resulting in extremely poor spinning properties and the goal was not achieved. It was not worth it. Furthermore, as a result of repeated studies on thermoplastic polymers containing cuprous iodide,
The present invention was completed based on the knowledge that the desired conductive fiber could be obtained by blending copper in a specific proportion and selecting a polymer that satisfies specific conditions.

That is, the present invention comprises component (A) consisting of a fiber-forming polymer, a thermoplastic polymer having a melt viscosity 1000 to 2500 poise lower than the melt viscosity of the fiber-forming polymer of component (A) at the spinning temperature, and the Consists of composite fibers formed from component (B), which is a mixture of cuprous iodide in an amount of 1.4 to 3.4 times the weight of the plastic polymer;
In addition, at least a part of the surface is related to conductive fibers formed from component (B).

The polymer serving as component (A) constituting a part of the conductive fiber of the present invention may be a fiber-forming polymer that can be melt-spun, and has a melt viscosity of 1,200 to 1,200 during melt-spinning.
5000 poise is preferred, and 1500 to 4000 poise is particularly preferred. Specific examples of such polymers include polyesters such as polyethylene terephthalate and polybutylene terephthalate, polyamides such as nylon 6 and nylon 66, polyolefins such as polyethylene and polypropylene, and polymers containing these as main components. Among these, polyester-based and polyamide-based polymers are preferred. Further, the polymer constituting component (A) may contain arbitrary additives such as a matting agent, a coloring agent, an oxidation stabilizer, a dyeability improver, etc., as necessary.

Further, it constitutes the conductive part of the conductive fiber of the present invention.
Component (B) consists of cuprous iodide and a thermoplastic polymer. The polymer in component (B) has a melt viscosity 1000 to 2500 poise lower than the melt viscosity of the fiber-forming polymer as component (A) at the melt spinning temperature, and does not cause decomposition etc. at the spinning temperature. As long as it is thermally stable and melt-extrudable, it may or may not have fiber-forming ability. If the melt viscosity of the polymer in component (B) is higher than [melt viscosity of component (A) - 1000 (poise)] at the melt spinning temperature, when cuprous iodide is mixed,
The melt viscosity of component (B) becomes too high, making it impossible to spin conductive fibers in a stable state, and the melt viscosity of component (B) is lower than [melt viscosity of component (A) - 2500 (poise)]. When using the resulting conductive fiber,
(B) Cracks occur in the component part, resulting in a significant decrease in conductive performance. Specific examples of the polymer in component (B) include polyester, polyamide, polyether, polyolefin, etc., or polymers containing these as main components, and the degree of polymerization and/or the third component The type and amount may be appropriately selected to achieve a predetermined melt viscosity. Among these polymers, preferred are polymers of the same type as the polymer of component (A), or polymers containing the same type of polymer as a main component.

Any method can be used to mix the polymer in component (B) and cuprous iodide as long as it can be dispersed well. The amount of cuprous iodide mixed depends on the required conductive performance, but conductive fibers for antistatic applications are required to have an electrical resistance of 10 ¹² Ω/cm or less against a DC voltage of 1 KV. Therefore, the volume electrical resistivity of component (B) needs to be 10 ³ Ω・cm or less, taking into account the decrease in conductivity during stretching after spinning.
It needs to be at least 1.4 times the weight of the polymer in the ingredients. On the other hand, if the amount of cuprous iodide mixed is too large, it will be difficult to adjust the component (B) and spin.
It is appropriate that the weight be 3.4 times or less the weight of the polymer in component (B). Furthermore, optional additives such as matting agents, coloring agents, oxidation stabilizers, etc. can be included in component (B) as required.

The shape of the composite fiber composed of the above components (A) and (B) may be either side-by-side type or core-sheath type, but at least a part of its surface is formed by (B). It should be made up of ingredients. For example, when making a core-sheath type composite fiber by using component (B) in the core and component (A) in the sheath, a defective part is provided in a part of the sheath, and the defective part is filled with (B). ) It is necessary to fill the ingredients. When component (B) forms a complete core and the entire surface is composed of component (A), antistatic performance cannot be fully exhibited.

Furthermore, although the ratio of component (A) and component (B) in the cross section of the fiber can be set within an extremely wide range, (B)
If the proportion of the component becomes too large, the strength of the resulting conductive fiber will decrease, so the area occupied by component (B) in the cross section of the fiber is preferably 50% or less. In addition, there is no need to set a lower limit for component (B) as long as component (B) exists continuously along the fiber axis direction, but it is usually 1% or more in terms of area in the cross section of the fiber, especially It is preferable to make it 3% or more.

It is not necessary to adopt special methods and conditions to produce such composite fibers, and the melt spinning method and conditions for producing composite fibers consisting of two components can be arbitrarily adopted depending on the component (A). . Further, the fibers obtained by spinning can be drawn as necessary, and any drawing method and conditions may be used as appropriate.

The conductive fiber of the present invention uses white cuprous iodide as a conductive substance and contains the component (A) that forms ordinary synthetic fibers, so it has an extremely good color tone and a sufficient amount of It has strength, can be dyed in any color by conventional methods, and its conductive performance does not deteriorate during processing or use, eliminating all the drawbacks of conventional conductive fibers. Therefore, it can be applied to any field where conductive performance is required.

The conductive fibers of the present invention will be explained in further detail with reference to Examples below. The conditions for measuring the volume resistivity of the conductive composition in the examples were 20°C, 30% RH, and 3V DC voltage, and the conditions for measuring the electrical resistance of the conductive fiber single yarn were 20°C, 30% RH, and 3V DC voltage.
℃, 30%RH, 1KV DC voltage. Melt viscosity was measured using a Shimadzu elevated flow tester (PAT No.) with a nozzle diameter of 0.5φ x 4 mm and a load of 20 kg.
166642).

Example 1 100 parts by weight of cuprous iodide (manufactured by Kisan Kinzoku Co., Ltd.) and 40 parts by weight of polyethylene terephthalate with an intrinsic viscosity of 0.365 (melt viscosity at 280°C is 190 poise) were mixed at 280°C under a nitrogen stream at normal pressure. Volume resistance value 1.1×10 ² Ωcm after melt mixing for 30 minutes, melt viscosity at 280℃
A conductive composition of 2700 poise was obtained.

The above conductive composition is used as component (B), and the intrinsic viscosity is 0.65.
A spinneret with 6 eccentric core-sheath spinning holes (0.3 mmφ) in which a portion of the core overlaps with the sheath, using polyethylene terephthalate (melt viscosity at 280°C: 2500 poise) as component (A). Apply component (B) to the core and component (A) to the sheath, and adjust the spinning temperature.
360 denier at 280℃ and spinning speed of 400 m/min, area ratio of component (A) and component (B) in fiber cross section is 4:1
Obtain an undrawn composite fiber of
Stretched 3.0 times. Approximately 20% of the surface of the obtained composite fiber is composed of component (B), and the electrical resistance is
It had a resistance of 6.8×10 ⁷ Ω/cm, a strength of 300 g, an elongation of 50%, and a white color.

Comparative Example 1 The same procedure as in Example 1 was carried out except that a spinneret having 6 concentric core-sheath spinning holes (0.3 mmφ) was used in place of the spinneret used in Example 1. A composite fiber composed entirely of component (A) was obtained. The resulting drawn yarn has an electrical resistance of 5.3×10 ¹²
Ω/cm, strength 350g, and elongation 50%.

Example 2 Polyethylene (J3519 manufactured by Ube Industries, Ltd.,
The melt viscosity at 280°C was molten and mixed with cuprous iodide in the same manner as in Example 1, except that the melt viscosity at 280°C was 7.5×10 ² Ωcm, and the melt viscosity at 280°C was
A conductive composition of 2480 poise was obtained.

The conductive composition was spun and drawn in the same manner as in Example 1 except that this conductive composition was used as component (B), and the electrical resistance was 2.1.
A white conductive fiber of ×10 ⁸ Ω/cm was obtained.

Example 3 40 parts by weight of 6-nylon (melt viscosity 270 poise at 260°C) with an intrinsic viscosity of 0.86 and 100 parts by weight of cuprous iodide were melt-mixed at 260°C for 30 minutes under a nitrogen stream at normal pressure to determine the volume resistance. 1.5×10 ² Ω・cm, melt viscosity at 260℃
A conductive composition of 1600 poise was obtained.

This conductive composition is used as component (B), and has an intrinsic viscosity of 1.12.
Using the same spinneret as in Example 1, using 6-nylon (melt viscosity at 260°C: 1500 poise) as component (A), component (B) was added to the core and component (A) was added to the sheath. was applied to obtain an undrawn composite fiber of 360 denier at a spinning temperature of 260°C and a spinning speed of 300 m/min, with an area ratio of components (A) and (B) in the fiber cross section of 4:1, and then at a drawing temperature of 185°C. Electrical resistance after stretching 3.0 times at °C: 8.1×10 ⁷
A white conductive fiber with Ω/cm, tenacity of 500 g, and elongation of 40% was obtained.

Claims (1)

[Scope of Claims] 1 Component (A) consisting of a fiber-forming polymer and a thermoplastic polymer having a melt viscosity 1000 to 2500 poise lower than the melt viscosity of the fiber-forming polymer of component (A) at the spinning temperature. 1.4 to 3.4 for the thermoplastic polymer
A conductive fiber comprising a conjugate fiber formed from component (B) consisting of a mixture with twice the weight of cuprous iodide, and at least a portion of its surface is formed by component (B). 2 The area ratio of component (B) in the fiber cross section is 50%
The conductive fiber according to claim 1, which is as follows.