TECHNICAL FIELD

The present invention concerns a method for producing an electro-conductive fiber, and more particularly a method for imparting a property of absorbing or shielding electromagnetic waves.

BACKGROUND ART

Generally, a conductive plate is one of the most effective ways to electrostatically shield electromagnetic waves and particles generated from various electromagnetic instruments. However, this kind of shielding is practically impossible to apply to the man-machine interface that an operator must have a relation with a machine such as a computer terminal, electromagnetic medical instrument, etc. Exposing to the electromagnetic wave causes various medical syndromes in the human body.

In order to protect the human body from the electromagnetic waves, there has been proposed clothing, apron, spectacles, etc. manufactured from fibers to shield the electromagnetic waves. Conventionally, such a fiber is made interwoven with very thin copper threads. However, the copper threads make the fiber inflexible giving unpleasant feeling to the human body contacting them.

DISCLOSURE OF INVENTION

It is an object of the present invention to provide a method for producing a electro-conductive fiber, whose flexibility and adaptability for human body are compared to those of normal fibers.

According to the present invention, a method for fabricating an electro-conductive fiber comprises the steps of:

treating a basic fiber composed of filaments of polyester or acrylic

series with 2 to 3 gr of sodium hydroxide and non-ionic surfactant at a temperature of 30 to 40°C for about five minutes;

washing sufficiently the treated fiber in a hot bath of 60 to 70 ^° C ;

etching the washed fiber with a liquid solution mixed with hydrochloric acid of 50ml and nitric acid of 10ml at room temperature for about thirty minutes;

immersing the etched fiber in a liquid solution mixed with palladium chloride of 2gr and tin chloride of 2gr added with chloric acid (Hcl) at a temperature of 20 to 50 °C for about ten minutes after washing;

washing to remove the tin from the fiber, and immersing the fiber in a liquid solution of sodium hydroxide of 50gr at room temperature to remove residual tin;

immersing the fiber in a liquid solution mixed with cupric sulfate of 20gr, sodium hydroxide of 40gr and rosolic salt of 160gr added with 37% formalin at a temperature of 40 to 50 ^° C for 10 to 15 minutes; and

immersing the fiber in a liquid solution mixed with sulfate nickel of 20gr, citric acid of 15gr and sodium hypophosphite of 30gr at a temperature of 30 to 40°C for about ten minutes (nickel formed with a thickness of about 0.2μm).

The present invention is described more specifically in the following examples:

BEST MODE FOR CARRYING OUT THE INVENTION

Example 1.

A basic fiber composed of filaments of polyester or acrylic series is treated with 2 to 3 gr of sodium hydroxide and non-ionic surfactant at a temperature of 30 to 40°C for about five minutes so as to remove impurities therefrom. Then, the treated fiber is washed sufficiently in

a hot bath of 60 to 70 ^° C.

The washed fiber is etched with a liquid solution mixed with hydrochloric acid of 50ml and nitric acid of 10ml at room temperature for about thirty minutes. The etched fiber is immersed in a liquid solution mixed with palladium chloride of 2gr and tin chloride of 2gr added with chloric acid (Hcl) at a temperature of 20 to 50 ^° C for about ten minutes after washing.

Thereafter, the immersed fiber is washed to remove the tin, and immersed in a liquid solution of sodium hydroxide of 50gr at room temperature to remove residual tin, so as to make the catalyst palladium only form the nucleus.

Again, the fiber is immersed in a liquid solution mixed with cupric sulfate of 20gr, sodium hydroxide of 40gr and rosolic salt of 160gr added with 37% formalin at a temperature of 40 to 50 ^° C for 10 to 15 minutes, whereby a copper coating of high purity is formed with a thickness of Iμm. Because the copper coating is rapidly oxidized, the copper coated fiber is immersed in a liquid solution mixed with sulfate nickel of 20gr, citric acid of 15gr and sodium hypophosphite of 30gr at a temperature of 30 to 40°C for about ten minutes (nickel formed with a thickness of about 0.2 m), so as to form a thin film on the copper coating.

Finally, dried by hot blowing after washing, the thin copper coating of the fiber has an electrical resistivity of 0.5 - 1.2m, and a thickness of 0.8 - 1. μm forming a thin film on the basic fiber, thus providing the fiber with an electrical conductivity. If desired, a silver or gold coating is additionally carried out so as to reinforce the thin film as well as electrical conductivity with or without electrolysis.

In this way, the traditional fiber is coated with a very thin film of electrical conductivity, which is formed around the fiber nucleus of non-electrical conductivity, so that the fiber has electrical conductivity without losing the desired physical properties of the

traditional fiber.

Example 2.

In this example, a basic fiber composed of filaments of a nylon is treated with 2 to 3 gr of sodium hydroxide and non-ionic surfactant so as to remove impurities therefrom. Then, the treated fiber is washed sufficiently in a hot bath of 60 to 70 ^* C. The washed fiber is etched with a liquid solution mixed with hydrochloric acid of 20ml and nitric acid of 2 to 5ml at a room temperature of 40 to 50°C for 20 to 30 minutes. The etched fiber is immersed in a liquid solution of hydrochloric acid of 100ml at room temperature for about five minutes to perform the secondary etching after washing. The subsequent processing steps are the same as Example 1.

INDUSTRIAL APPLICABILITY

The fibers obtained by using the inventive method have the flexibility and adaptability for human body, which are compared to the traditional fibers and may serve as an electrostatic shield garment, apron, meshed spectacles, wall paper, gasket, etc. used in a factory for fabricating semiconductor devices.