JP5213052B2 - Stretchable conductive fiber and manufacturing method thereof - Google Patents

Description

  The present invention relates to a conductive fiber and a method for producing the same, and more particularly to a stretchable conductive fiber that can obtain stable conductive performance even when the fiber is deformed and deformed, and a method for producing the same.

  Elastic yarn (elastomer fiber) is used for apparel applications such as outer, inner, sports, legs, materials for car seats and shoes, medical applications such as supporters and taping, etc. Widely used. However, for example, polyurethane elastic yarns are inferior in conductivity as compared to other fibers, and therefore fabrics with an increased mixing ratio of polyurethane elastic yarns have problems such as dust adhesion and generation of static electricity.

  In Patent Document 1, as a stretchable composite elastic yarn, a polyurethane elastic yarn having a breaking elongation of 400% or more and a fineness of 70 to 460 denier is used as a stretchable elastic yarn constituting the core portion, and a sheath portion. The sheath is made of a thermoplastic polymer such as a polyester polymer, and the core is made of a composite fiber made of a low-melting-point metal. A stretchable composite elastic yarn is disclosed in which the composite yarn covers around. However, since the conductive composite yarn constituting the sheath portion of the stretchable composite elastic yarn is not stretchable, there is a problem in the yarn making process and the yarn processing step, and the core portion is cracked during use and the core portion is It may be exposed on the surface, which may reduce product quality or reduce electrostatic performance. In addition, the manufacturing process of the stretchable composite elastic yarn is complicated and expensive.

Patent Document 2 discloses a technique for obtaining a conductive polyurethane yarn by adding acetylene black having a BET specific surface area of 50 m ² / g or more to a spinning solution of polyurethane yarn. However, it is said that it is difficult to obtain a stable conductive performance when there is a problem of lowering the spinning performance, yarn strength, stretching performance, or when acetylene black is not uniformly dispersed.

  Moreover, in patent document 3, a fiber is immersed in the aqueous solution containing a copper ion, a copper ion is made to adsorb | suck to the fiber surface, it is immersed in the aqueous solution containing an iodide ion, copper iodide is formed on a fiber, electric conduction and A technique for enhancing antibacterial properties is described. However, some of the fibers obtained by this method have cracks in the copper iodide on the fiber surface when the fibers are expanded and contracted, leading to a decrease in conductive performance and product quality.

In addition, in Patent Document 4, after immersing fibers in an aqueous solution containing iodine ions and impregnating iodine inside the fiber surface, the fibers are treated with an aqueous solution containing monovalent copper ions. Discloses a technique in which a conductive layer made of copper iodide is formed in the vicinity of the inside of the surface. However, when the conductive fiber obtained by this method is used in an electronic device or the like, there has been a problem that excessive iodine is sublimated from the inside during use and adversely affects the electronic device.
JP-A-5-214646 JP-A-2005-281878 JP-A-5-247842 Japanese Patent Application No. 2008-195962.

  A conductive layer made of copper iodide is formed in the vicinity of the inner surface (sheath portion) of the elastic fiber, so that excess iodine is not sublimated from the inside during use, and is durable, resulting in a decrease in conductive performance. The object is to obtain a non-stretchable conductive fiber.

  The present invention has been made in view of such a technical background, and made a stretchable fiber having a core-sheath structure, making the core portion a stretchable fiber that is hard to be impregnated with iodine, and the sheath portion is easily impregnated with iodine. It has been found that by using a stretchable fiber, it is possible to obtain a stretchable conductive fiber in which excess iodine does not sublimate and leave from the inside during use by preventing excessive iodine from being impregnated and remaining inside. did. The present invention provides the following means to achieve the above object.

[1] A core-sheath stretchable fiber is immersed in an aqueous solution containing iodine ions, and the sheath of the fiber is impregnated with iodine, and then the fiber is treated with an aqueous solution containing monovalent copper ions, A method for producing a stretchable conductive fiber, comprising forming a conductive layer made of copper iodide on a sheath of the fiber.

[2] The method for producing a stretchable conductive fiber according to item 1 above, wherein the sheath portion of the stretchable fiber having the core-sheath structure is a polyester elastomer and the core portion is a polyolefin elastomer.

[3] Stretchable conductive fiber manufactured by the manufacturing method described in the preceding item 1 or 2.

[4] A stretchable conductive fiber produced by the production method described in the preceding item 1 or 2, wherein the volume resistivity in a steady state is 5.0 × 10 ² Ω · cm or less and the volume resistivity at 40% elongation 2.5 × 10 ³ Ω · cm or less, and a volume resistivity at 100% elongation of 5.0 × 10 ³ Ω · cm or less is a stretchable conductive fiber.

In the invention of [1], since stretchable fibers having a core-sheath structure are immersed in an aqueous solution containing iodine ions, iodine enters the inside from the sheath of the fiber, the sheath is impregnated with iodine, and the core is impregnated. It is difficult, and it is difficult for excess iodine to reach the core. After that, by treating the stretchable fiber with an aqueous solution containing monovalent copper ions, iodine impregnated in the fiber sheath reacts with copper to form a conductive layer made of copper iodide on the fiber sheath. can do. It is not a structure in which a conductive layer adheres to the surface of the fiber, but a conductive layer is formed inside the fiber, so that good conductive performance can be obtained, it is durable, and it is also resistant to shape changes such as expansion and contraction. It can be made into the manufacturing method of the elastic conductive fiber which does not cause a fall easily, and an iodine does not sublimate and detach | leave from an inside during use.

In the invention of [2], since the sheath part of the stretchable fiber having the core-sheath structure is a polyester elastomer that is easily impregnated with iodine, iodine is impregnated into the sheath part, and the core part is a polyolefin elastomer that is difficult to impregnate with iodine. Therefore, iodine impregnating the sheath does not impregnate the core. Therefore, when it processes with the aqueous solution containing a monovalent | monohydric copper ion, it can be set as the manufacturing method of the stretchable conductive fiber in which excess iodine does not remain inside a fiber.

In the invention of [3], since it is manufactured by the manufacturing method described in the preceding item 1 or 2, it has excellent conductive performance without impairing the flexibility of the fiber, and the expansion and contraction in which iodine does not sublimate from the inside during use. Conductive fiber.

In the invention of [4], the volume resistivity in the steady state is 5.0 × 10 ² Ω · cm or less and the volume resistivity at 40% elongation is 2. 5 × 10 ³ Ω · cm or less, and volume resistivity at 100% elongation is 5.0 × 10 ³ Ω · cm or less, so that sufficient conductive performance can be obtained both in a steady state and in an elongated state. It is flexible and can be made into a stretchable conductive fiber in which iodine is not sublimated from the inside during use.

In this invention, as shown to the micrograph of FIGS. 1-4, the electroconductive layer of copper iodide is formed in the sheath part of the stretchable fiber of a core sheath structure. Conventionally, in the process of imparting functionality to the fiber, there are many processing methods to attach the functional material to the surface of the fiber using a binder resin, etc., and the durability problem that the functional material peels off during washing and use There was a problem that the texture became hard. In the present invention, utilizing the property that iodine ions are easily impregnated inside the fiber and the property that iodine ions adsorb metals, the iodine ions impregnated inside the fibers penetrate the metal into the fibers, A conductive film is produced by forming a metal film. I ₃ ^- or I ₅ ^- is preferable as the iodine ion, and it is easy to impregnate the inside near the surface side of the fiber and easily adsorb the metal. In particular, the present invention applies the property that monovalent copper ions and iodine ions are easily bonded to each other and a copper iodide film is easily formed.

  In one embodiment of the present invention, as the first step, an aqueous solution containing iodine ions is prepared, and a stretchable fiber having a core-sheath structure is immersed to impregnate the sheath of the fiber with iodine. The aqueous solution containing iodine ions is prepared by, for example, dissolving iodine at room temperature in an aqueous solution containing potassium iodide or sodium iodide. The concentration of iodine is preferably 0.1 to 3.0 mol / L. If it exceeds 3.0 mol / L, excessive iodine reduces the tensile strength and elongation of the fiber, and excessive iodine is sublimated during use, which is not preferable. Moreover, even if it is less than 0.1 mol / L, the iodine density of the sheath part of a fiber will fall and it will increase a volume resistivity, and is unpreferable. Next, the fiber is immersed in an aqueous solution containing the iodine ions. Immersion treatment is performed at room temperature to 85 ° C. for 10 to 90 minutes, and the fiber sheath is impregnated with iodine. The fiber of the sheath at this time is not particularly limited, but is suitable because the polyester fiber is easily impregnated with iodine. The elastic sheath fiber is preferably an elastomer fiber, and the effect is particularly remarkable when the polyester elastomer fiber is processed.

  Further, the thickness of the stretchable sheath portion fiber depends on the fiber fineness of the core portion. For example, in the case of a monofilament yarn having a diameter of 0.6 mm, 20 to 100 μm is preferable. If the thickness of the stretchable sheath fiber is less than 20 μm, stable conductivity cannot be obtained when stretched, and even if the thickness exceeds 100 μm, the copper iodide film becomes thick and the stretch performance deteriorates or feels. It becomes hard and is not preferable. More preferably, 30-70 micrometers is good.

  Moreover, the fiber of the core part is not particularly limited, but it is preferable because the polyolefin fiber hardly impregnates iodine. In addition, as the core fiber having elasticity, an elastomer fiber is preferable, and a polyolefin elastomer fiber is particularly preferable.

  Next, as a second step, the fiber impregnated with iodine in the fiber sheath is taken out from the aqueous iodine solution, squeezed with a mangle, and then into an aqueous solution containing monovalent copper ions at 65 to 85 ° C. for 10 to 90 minutes. By dipping, the iodine ions that have entered the fiber sheath in the previous step react with monovalent copper ions to form a conductive layer made of copper iodide on the fiber sheath. Monovalent copper ions and iodine ions are easy to bond and form a film. If it wash | cleans after that and it dries, the fiber by which the electroconductive layer which consists of copper iodide was formed in the sheath part of a fiber can be manufactured.

  The aqueous solution containing monovalent copper ions is prepared by, for example, dissolving cuprous chloride in an aqueous solution containing ammonium ions. The concentration of monovalent copper ions is preferably 0.1 to 0.5 mol / L, and the reaction temperature is preferably 65 to 85 ° C. If it is less than 0.1 mol / L, a sufficient amount of copper iodide cannot be formed. Moreover, even if it exceeds 0.5 mol / L, the amount of copper iodide formed does not increase, which is not preferable. Further, when the reaction temperature is lower than 65 ° C., it is difficult to form copper iodide, and even if it exceeds 85 ° C., the amount of copper iodide formed does not increase, and the aqueous solution is close to the boiling point, which is not preferable.

  If the fiber for producing the conductive fiber is an elastomer fiber, the conductive fiber having excellent stretchability can be produced. Elastomer fibers are inherently large in electrical resistance, easily charged by friction, and have the property of sucking dust and dirt and deteriorating their appearance, and can be used in applications where antistatic and electrical conductivity are required. It was restricted. As a conventional method for imparting conductivity to elastomer fibers, it has been known to impart antistatic properties and conductivity by blending conductive carbon black. Variations occurred and the volume resistivity was not constant. Moreover, it was black and limited in design. Since the present invention stably forms the conductive layer inside the fiber, the above-mentioned drawbacks can be solved and an elastomer fiber excellent in antistatic property, flexibility and stretchability can be obtained.

  Further, if the fiber constituting the conductive fiber is a polyester elastomer fiber, the polyester fiber has a property of being easily impregnated with iodine, so that it can be made an elastomer fiber excellent in stretchability that can provide more stable conductive performance. .

Further, the volume resistivity in a steady state is 5.0 × 10 ² Ω · cm or less, the volume resistivity at 40% elongation is 2.5 × 10 ³ Ω · cm or less, and the volume resistivity at 100% elongation is Since it is 5.0 × 10 ³ Ω · cm or less, it can be applied to various sensors by applying the property that the volume resistivity changes with the amount of displacement of the conductive fiber. .

  Next, examples of the present invention will be described, but the scope of the present invention is not limited to these examples. The volume resistivity was measured with the following measuring instrument.

<Test method>
Volume resistivity: measured by a resistivity meter (Lorestar GP, manufactured by Mitsubishi Chemical Corporation).

<Example 1>
Prepare ethylene propylene elastomer elastic yarn (monofilament yarn 5000dtex) as polyolefin elastomer elastic yarn, pass through polyester elastomer resin solution (polyester-polyether elastomer resin, 10% by weight solution using methylene chloride as solvent), and dry at 50 ° C. Thus, a stretchable fiber (initial volume resistivity 6.8 × 10 ¹³ Ω · cm) having a core-sheath structure was prepared. Next, it is immersed in an aqueous solution containing iodine ions (iodine 0.2 mol / L, potassium iodide 3.0 mol / L, 80 ° C.) for 60 minutes, squeezed with a mangle, and impregnated with iodine in the sheath of the stretchable fiber I let you. The surface of the stretchable fiber was brown. Further, this stretchable fiber is immersed in an aqueous solution containing monovalent copper ions (an aqueous solution in which ₄₀ g of CuCl and 85 g of NH ₄ Cl are dissolved in 1 liter of water) at 85 ° C. for 60 minutes, so that the sheath of the stretchable fiber is formed. Iodine and copper were reacted to form copper iodide. The stretchable fiber was taken out of the bath, washed with water and dried with a dryer. The stretchable fiber became light yellow, indicating that copper iodide was formed in the sheath of the stretchable fiber. (Shown in FIGS. 1 to 4. The thickness of the sheath is 30 μm.) The volume resistivity in a steady state is 5.0 × 10 ¹ Ω · cm, and the volume resistivity at 40% elongation is 1.2 × 10 ² Ω. -The volume resistivity at the time of 100% elongation was 2 × 10 ² Ω · cm, and good conductivity could be obtained even in the stretched state. Next, the stretchable conductive fiber was put in a transparent acrylic box, heated to 80 ° C., and the wall surface of the acrylic box was observed (iodine release test), but no iodine release was observed.

<Example 2>
In Example 1, a stretchable conductive fiber having a core-sheath structure was obtained in the same manner as in Example 1 except that a polyester-polyurethane elastomer resin was used instead of the polyester- polyether elastomer resin . As in Example 1, the stretchable fiber became light yellow, indicating that copper iodide was formed on the sheath of the stretchable fiber. The volume resistivity in a steady state is 9.0 × 10 ¹ Ω · cm, the volume resistivity at 40% elongation is 2.9 × 10 ² Ω · cm, and the volume resistivity at 100% elongation is 6.4 ×. 10 ² Ω · cm was exhibited, and good conductivity could be obtained even in the stretched state. In the iodine withdrawal test, no iodine withdrawal was observed.

<Comparative Example 1>
In Example 1, it was conducted in the same manner as in Example 1 except that the polyester elastomer fiber (polyester monofilament yarn 5000 dtex, initial volume resistivity 2.5 × 10 ¹³ Ω · cm) was used instead of the core-sheath stretchable fiber. Fiber was obtained. As shown in FIG. 5, it can be seen that the copper iodide is firmly formed inside the surface of the polyester elastomer fiber, and a part of the copper iodide penetrates deeper than the surface. The volume resistivity in a steady state is 1.9 × 10 ² Ω · cm, the volume resistivity at 40% elongation is 9.5 × 10 ² Ω · cm, and the volume resistivity at 100% elongation is 2.0 ×. It was 10 ³ Ω · cm, and a conductive fiber having good durability and conductivity could be obtained. Although good conductivity was obtained even in the stretched state, in the iodine detachment test, the wall surface of the acrylic box was clouded in brown, and iodine detachment was observed.

<Comparative example 2>
A conductive fiber was obtained in the same manner as in Example 1 except that nylon monofilament (5000 dtex) was used instead of the ethylene propylene elastomer elastic yarn. Copper iodide was formed in the fiber sheath, but iodine also penetrated into the core nylon. Although the volume resistivity in a steady state was 5.1 × 10 ¹ Ω · cm, the volume resistivity at 40% and 100% elongation could not be measured because there was no elongation. In the iodine detachment test, the wall surface of the acrylic box clouded brown as in Comparative Example 1, and iodine detachment was observed.

It is a microscope picture which shows the cross section of the stretchable conductive fiber which concerns on Example 1 of this invention. (Magnification 100) It is a microscope picture which shows the cross section of the stretchable conductive fiber which concerns on Example 1 of this invention. (Magnification 500) It is a microscope picture which shows the longitudinal cross-section of the stretchable conductive fiber which concerns on Example 1 of this invention. (Magnification 100) It is a microscope picture which shows the longitudinal cross-section of the stretchable conductive fiber which concerns on Example 1 of this invention. (Magnification 500) It is a microscope picture which shows the cross section of the stretchable conductive fiber which concerns on the comparative example 1 of this invention. (Magnification 300)

Claims (3)

A core- sheath stretchable fiber whose sheath is made of polyester elastomer and whose core is made of polyolefin elastomer is immersed in an aqueous solution containing iodine ions, and after impregnating iodine in the sheath of the fiber, the fiber is monovalent. A process for producing a stretchable conductive fiber, wherein a conductive layer made of copper iodide is formed on a sheath of the fiber by treating with an aqueous solution containing copper ions. A stretchable conductive fiber produced by the production method according to claim 1 . A stretchable conductive fiber manufactured by the manufacturing method according to claim 1, wherein the volume resistivity in a steady state is 5.0 × 10 ² Ω · cm or less, and the volume resistivity at 40% elongation is 2.5. A stretchable conductive fiber having a volume resistivity of not more than × 10 ³ Ω · cm and a 100% elongation of 5.0 × 10 ³ Ω · cm or less.