JP2894493B2 - Method for producing silver-coated organic fiber - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION (Industrial application field) The present invention relates to an organic fiber coated with silver, wherein a short fiber is used as a conductive filler in a conductive paint or the like, and a long fiber is used as a woven fabric, a nonwoven fabric or a yarn. Used for electromagnetic wave shielding material, antistatic material, etc. Here, the organic fibers are fibers of natural and synthetic organic substances, that is, fibers of cotton, silk, hemp, regenerated cellulose, polyamide, acrylic, polyolefin and the like.

(Prior art and its problems) Conventionally, organic fibers coated with nickel or copper have been used as woven or non-woven fabrics for electromagnetic wave shielding materials, etc. Nickel has a higher resistance than copper and silver. Since the shielding effect is not sufficient and copper is easily oxidized, initial performance cannot be maintained, and both of them lack reliability and their use is limited. The use of metal fibers themselves as woven or non-woven fabrics is also being considered, but stainless steel and nickel have high resistance, and copper is easily oxidized. Absent.

On the other hand, there are gold and silver yarns in which gold and silver are deposited on the yarn by the spattering method. However, these are not mass-produced, are expensive, are mainly used for decorative purposes, and are limited to use as yarn. .

(Objects of the Invention) In view of these circumstances, the present inventors have repeatedly studied organic fibers having low resistance, excellent oxidation resistance, and a wide range of application.
The present inventors have found that a high-performance organic fiber that solves the conventional problems can be obtained by coating the organic fiber with silver by an electroless plating method, and has reached the present invention.

(Constitution of the Invention) That is, according to the present invention, an organic fiber having a thickness of 0.1 to 15 denier before weaving is activated with a stannous salt, and then a silver salt, a silver complexing agent and a reducing agent are mixed. by treatment with an electroless plating method using, and wherein the covering 15 to 40 wt% silver to the fiber resistance when compressed at a pressure of 50 kg / cm ² between the sample 1g of the cross-sectional area 2 cm ² electrode A method for producing a silver-coated organic fiber having a value of the order of 10 ⁻³ Ω or less is provided.

Thus, the organic fiber of the present invention has a thickness of 0.1d to 15d.
And silver coverage by electroless plating is 15-40 wt%
(In the present invention, the coating amount of silver is a value based on the fiber weight after coating), and is preferably in the range of 15 to 30% by weight.

If the fiber is thinner than 0.1d, the silver coverage increases and the specific gravity is not much different from silver.If the fiber is thicker than 15d, the silver coverage can be reduced, but the fiber becomes hard and difficult to spread. Become.

If the silver coverage is less than 15 wt%, the fibers cannot be sufficiently coated, resulting in poor conductivity. If the silver coverage is more than 40 wt%, the specific gravity increases and the conductivity does not differ much.

The silver-coated organic fiber of the present invention is produced by an electroless plating method.

Electroless plated process of silver, S in aqueous hydrochloric acid pre SnCl ₂
n Activated organic fibers are immersed in an aqueous solution containing (1) a silver complexing agent and a reducing agent, and a silver salt aqueous solution is dropped.
(2) A method of immersing in an aqueous solution containing a silver salt and a complexing agent and dropping an aqueous solution of a reducing agent; Any of these methods may be used.

As the silver salt, silver nitrate or a solution of silver dissolved in nitric acid is used. As the complexing agent, aqueous ammonia and / or
Alternatively, salts such as ethylenediaminetetraacetic acid, nitrilotriacetic acid, and triethylenetetraminehexaacetic acid are used, and as a reducing agent, formalin, hydrazine and its derivatives, tartaric acid, glucose and the like are used.

The length of the organic fiber of the present invention is not limited because it is selected depending on the application.For example, when used as a conductive filler, it is about 0.1 mm to 2 mm, and when used as a nonwoven fabric, it is 30 mm to
When it is used as a woven fabric, a short fiber is spun or used as a long filament.

Next, the present invention will be described specifically with reference to Examples.
The following examples do not limit the scope of the invention.

Example 1 30 g of an acrylic fiber having a thickness of 1.5 d and a length of 0.5 mm was scoured and degreased, and then immersed in an aqueous solution containing 10 g / l of SnCl _{2 and} 10 ml / l of HC to activate Sn. It was immersed in 2 liters of liquid, and 500 ml of liquid B was added dropwise with stirring. Reaction temperature is 20 ° C.

After the reaction was completed, the product was washed and dried, yielding 39.7 g
As a result, silver-white short fibers coated with 24.4% by weight of silver were obtained.

Comparative Example 1 30 g of the same acrylic fiber as in Example 1 was similarly immersed in an aqueous solution containing Sn activation, PdCl ₂ 1 g / l and HC 1 ml / l to activate Pd, and immersed and stirred at 30 ° C. in 2 l of the following composition did.

After the reaction, the product was washed with water and dried, yielding 39.6 g of copper and 2
4.2 wt% coated short fibers were obtained.

Comparative Example 2 In the same manner as in Comparative Example 1, Pd-activated acrylic fibers were immersed and stirred in 2 l of a liquid having the following composition at 80 ° C.

After the reaction was completed, the product was washed and dried, yielding 39.2 g,
Short fibers coated with 23.5% by weight of nickel were obtained.

Comparative Test 1 Each of the samples of Example 1, Comparative Examples 1 and 2 was mixed and dispersed in an acrylic paint (Kansai Paint No. 2026GL Clear) at 10 wt%, and applied to a PET film with a thickness of 100 μm.
Table 1 shows the results of measuring the surface resistance before and after the sample was kept in saturated steam at 2 ° C. for 2 hours by the four probe method.

Example 2 40 g of a polyamide fiber having a thickness of 3 d and a length of 76 mm was activated with Sn in the same manner as in Example 1, immersed in 2 liters of solution A having the following composition, and 500 ml of solution B was dropped while circulating the solution with a pump. did. Reaction temperature is 20 ° C.

After the reaction was completed, the product was washed with water and dried, yielding 49.6 g and 1 silver.
A silver-white fiber coated with 9.4% by weight was obtained.

Comparative Example 3 In the same manner as in Comparative Example 1, 40 g of the same polyamide fiber as in Example 2 was activated, followed by Pd activation after Sn activation and copper plating. The yield was 49.7 g, and a fiber coated with 19.5 wt% of copper was obtained.

Comparative Example 4 As in Comparative Example 3, after the Sn activation, the Pd-activated polyamide fiber was nickel-plated in the same manner as in Comparative Example 2.
The yield was 49.4 g, and a fiber coated with 19.0% by weight of nickel was obtained.

Comparative test 2 The samples of Example 2, Comparative examples 3 and 4 were immersed in saturated steam at 80 ° C.
Table 2 shows the results of measuring the resistance value by pressing before and after holding for a time. The pressing conditions were such that 1 g of the sample was sandwiched between electrodes each having a copper column having a cross-sectional area of 2 cm ² and gold-plated, and 50 kg / cm.
^The compression is performed at the pressure of ² , and the resistance value is measured at that time.

(Effect of the Invention) The silver-coated organic fiber of the present invention has excellent oxidation resistance and conductivity as compared with the case where a fiber coated with copper or nickel is used by adopting the above-mentioned configuration, and its application range Is wide.

 ──────────────────────────────────────────────────続 き Continuation of front page (72) Motohiko Yoshizumi, Inventor 1-297 Kitabukuro-cho, Omiya-shi, Saitama Mitsubishi Metals Central Research Laboratory (56) References JP 47-8898 (JP, A) JP 47 −43159 (JP, B1)

Claims (1)

(57) [Claims] An organic fiber before weaving having a thickness of 0.1 to 15 denier is activated with a stannous salt, and then treated by an electroless plating method using a silver salt, a silver complexing agent and a reducing agent. to, and wherein the covering 15 to 40 wt% silver to the fiber resistance when compressed at a pressure of 50 kg / cm ² between the sample 1g of the cross-sectional area 2 cm ² electrode 10 ^-3 Omega table below A method for producing a silver-coated organic fiber.