JPH10310976A - Electromagnetic wave shielding fibrous structure - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain an electromagnetic wave shielding fibrous structure suitable as clothes when performing operations around electronic equipment or uses of industrial materials requiring electromagnetic wave shielding by using spun yarns containing silver-coated staple fibers. SOLUTION: This electromagnetic wave shielding fabric is obtained by coating the surfaces of polyamide-based fibers 2 having 25-78 mm fiber length with silver 3 in an amount within the range of 5.0-40.0 wt.% according to an electroless plating method, forming silver-coated staple fibers 4, then producing mixed yarns 1 containing the silver-coated staple fibers 4 in an amount of >3.0 wt.% except animal fibers such as animal hair or silk, arranging the resultant mixed yarns 1 in warp and weft yarns and weaving a woven fabric.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an electromagnetic wave shielding fiber which comprises a fiber whose surface is coated with silver, has an electromagnetic wave shielding performance, and can be widely used from industrial materials to clothing. It relates to structures.

[0002]

2. Description of the Related Art Conventionally, housings of electronic devices widely used in offices and homes have been made of metal. However, in recent years, plastics have been widely used for miniaturization and improvement of productivity. I have. However, compared to metal, plastic is equivalent to nothing electromagnetically, and electromagnetic waves emitted from inside the housing not only impair the reliability of operation of electronic devices inside and outside the housing, but also affect various organs of the human body. The impact on workers' health is not negligible, and calls for stronger regulations to reduce the intensity of electromagnetic fields applied to the human body have been called for. Various electromagnetic shielding fiber structures have been developed.

[0003] Examples thereof include yarns having electromagnetic wave shielding properties such as (A) stainless steel fiber, (B) metal-coated glass fiber, (C) carbon fiber, (D) brass fiber, and (E) aluminum fiber. Alternatively, in addition to such a yarn form, (F) a cloth having a surface coated with an electromagnetic shielding material such as silver or nickel after weaving is known. Also, (G) JP-A-5-186966 discloses that
After scouring 1.5d × 38 mm acrylic fiber, immersing it in an aqueous solution containing stannous chloride and hydrochloric acid, washing with water, and imparting catalytic properties to electroless silver plating, tetrasodium ethylenediaminetetraacetate, sodium hydroxide A non-woven fabric made of a fiber obtained by subjecting the acrylic fiber to silver plating using a plating solution consisting of a solution of formalin and ammoniacal silver nitrate is further described in (H) JP-A-5-48289. Synthetic fibers such as acrylic, fiberized synthetic resins such as polypropylene, polyethylene, and vinyl chloride; natural fibers such as cotton and wool; recycled fibers such as acetate and viscose;
Inorganic fibers such as carbon fiber, nickel, iron, cobalt,
Disclosed are nonwoven fabrics and the like obtained by foaming a papermaking liquid containing fibers plated with a metal such as silver or palladium, dispersing short fibers on the surface of the cells, and forming the resulting fibers.

However, since the above-mentioned (A) stainless steel fiber is produced by a drawing method, the production cost is high and the fiber is poor in spinnability.
Since (C) carbon fiber and (D) brass fiber are hard,
Although it can be used for industrial materials, it cannot be used for clothing. (E) Aluminum fiber has a problem that its surface is easily oxidized and cannot be used for clothing. After weaving, a cloth coated with silver or the like on its surface is difficult to use for clothing because it is weak to wear and unsuitable for thin fabrics.

Further, when an electromagnetic wave shielding material is contained in a fabric to obtain electromagnetic wave shielding performance, the amount of leakage of the electromagnetic wave is larger than the total area of voids between the electromagnetic wave shielding materials contained in the fabric. Since the area of each gap is proportional to the size of the area, if the total area of the gaps is the same, a cloth having many small gaps exhibits higher electromagnetic wave shielding performance as compared to a cloth having a small large gap. It is known.

Accordingly, the above-mentioned (G) Japanese Patent Application Laid-Open No. 5-18696
No. 6, (H) Japanese Unexamined Patent Publication No. Hei 5-48289, it is difficult to uniformly disperse the electromagnetic wave shielding material, resulting in non-uniform mixing ratio depending on the part. There is a problem that the material has a large gap between the electromagnetic wave shielding materials, resulting in poor electromagnetic wave shielding performance.

In order to solve these problems, filaments coated with an electromagnetic wave shielding material have recently been developed. In order to reduce the area of each void, it is necessary to arrange the filaments densely for both the warp and the weft, and if it is desired to obtain a desired electromagnetic wave shielding performance, the cost becomes extremely high. Had the problem that

[0008]

SUMMARY OF THE INVENTION The present invention has been made in view of the above points, and has as its object to provide a fiber structure having electromagnetic wave shielding performance and suitable for use in clothing.

[0009]

An object of the present invention is to provide a spun yarn having an electromagnetic wave shielding property, characterized in that silver-coated short fibers are contained in an amount exceeding 3.0% by weight based on the total amount.
And a spun yarn containing more than 3.0% by weight, based on the total amount, of silver-coated short fibers.

[0010]

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, the present invention will be described in detail.
FIG. 1 is a sectional view of the spun yarn of the present invention.

The spun yarn (1) of the present invention shown in FIG. 1 is made of a silver-coated short fiber (4) in which a short fiber (2) of a core is covered with silver (3). Here, the short fiber (2) of the core has a fiber length of 25 mm to 78 mm and is made of a cellulosic fiber such as cotton, rayon, solvent-spun cellulose, or polyethylene terephthalate.
Polyester made of polytetramethylene terephthalate, polyethylene oxybenzoate, poly 1,4-dimethylcyclohexane terephthalate, nylon 4, etc.
Nylon 6, Nylon 7, Nylon 11, Nylon 1
2, polyamide 66 such as nylon 66, nylon 6,10, polymeta-xylene adipamide, polyparaxylylene decanamide, polyolefin such as polypropylene and polyethylene, polyvinyl-based polymer such as polyvinyl chloride and polyvinylidene chloride, and the like. Staples of synthetic fibers made of polymers such as copolymers and modified materials can be used, but staples of polyamide fibers are preferred from the viewpoint of tensile strength. Animal fibers such as animal hair fibers and silk fibers are not suitable because they react with silver and reduce its effect.
In addition, as described above, in order to reduce the area of each void between silver-coated filaments in a fabric, it is necessary to arrange the silver-coated filaments densely for both the warp and the weft, and a desired electromagnetic wave shielding performance is obtained. Attempting to do so is extremely costly and unsuitable for clothing applications, and is not suitable.

The short fibers (2) are coated with silver (3) as an electromagnetic shielding material by using a known fiber structure metal coating method such as an electroless plating method, a sputtering method, or a metal deposition method. Cover. In general fiber structure metal coating processing, metals such as copper and nickel are also used as electromagnetic wave shielding materials other than silver, but these electromagnetic wave shielding materials have a large effect on the human body, so they are excellent. Uses silver that exhibits electromagnetic wave shielding properties and has no percutaneous absorption. At this time, the amount of silver (3) covering the short fibers (2) is 5.0 in the entire silver-coated short fibers (4).
If the amount is less than 4% by weight, the desired electromagnetic wave attenuation cannot be obtained because the film becomes thin, and if the amount exceeds 40.0% by weight, the cost becomes high. .

Next, a spun yarn (1) is produced using the silver-coated short fibers (4) thus obtained. Here, when blending with another short fiber (5), if the content of the silver-coated short fiber (4) in the spun yarn is 3.0% by weight or less, voids between the silver-coated short fibers (4) are increased. As described above, the desired electromagnetic wave shielding performance cannot be obtained as described above.
The silver-coated short fiber (4) preferably contains more than 3.0% by weight, preferably 10.0% by weight or more, more preferably 20.0% by weight or more based on the total amount of the spun yarn. Excellent effects can be obtained. As described above, animal fibers such as animal hair fibers and silk fibers react with silver (3) to reduce its effect, and therefore, it is not preferable to blend them with these.

When the silver-coated short fibers (4) are mixed into the other short fibers (5), they may be mixed in the drawing step, but a mixed cotton step is preferred for uniform dispersion. In the case of spinning with cotton, scouring and bleaching to remove cotton wax is preferred from the viewpoint of uniform dispersibility.

Then, using the above-mentioned raw materials, a blended cotton process
The spun yarn (1) of the present invention is manufactured through a carding step, a drawing step, a roving step, and a spinning step. In the spinning process,
A single spinning yarn is fed by feeding to a spinning machine such as a ring spinning machine or an open-end spinning machine. After the roving is supplied, the silver-coated short fiber (4) and other short fibers are fed in an air stream. It is preferable to use an open-end spinning machine because it is possible to eliminate the density difference of (5).

Subsequently, a fabric such as a woven fabric or a knitted fabric is manufactured using the spun yarn. At this time, if the mixing ratio of the spun yarn (1) having the electromagnetic wave shielding property is 40.0% by weight or more in the fabric, the void area between the mixed silver-coated short fibers (4) can be reduced. It becomes possible to obtain a fabric that exhibits excellent electromagnetic wave shielding performance. The fabric thus obtained has excellent conductivity and releases silver ions under humid conditions, so that E. coli, Staphylococcus aureus,
It also exhibits an excellent antibacterial effect against bacteria such as MRSA and Legionella bacteria and fungi such as Trichophyton, black mold and blue mold.

[0017]

Next, the present invention will be described in detail with reference to examples, but the present invention is not limited to these examples.

Example 1 A polyamide fiber of 1.4d made of nylon 6 was cut into a fiber length of 38 mm to form a short fiber, and the above polyamide short fiber was covered with silver by an electroless plating method. Here, the silver coating amount in the silver-coated short fibers was adjusted to 20.0% by weight.

Next, both 5.0% of the silver-coated short fibers and 95.0% of the cotton are uniformly mixed in a cotton blending step.
Further, after passing through a carding step and a drawing step, it is supplied to a roving step and twisted at 1.1 times / inch to obtain a roving of 0.9 g / m. Supplied to an open-end spinning machine, Z-twist, 32 turns / inch, 40th (English cotton count)
The spun single yarn having the electromagnetic wave shielding performance of Example 1 is spun, and the electromagnetic wave shielding spun yarn thus obtained is woven at a warp of 144 yarns / inch and a weft of 70 yarns / inch to obtain the fabric of Example 1. Obtained. That is, the content of silver in the fabric of Example 1 was 5.0 × 20.0 = 1.0%.

Comparative Example 1 A 1.4 d filament of polyamide fiber made of nylon 6 was coated with silver by an electroless plating method. Here, the silver coating amount of the silver-coated filament was set to 20.0% by weight as in Example 1.

Subsequently, the silver-coated filament 5.0 described above was used.
Using 95.0% by weight of spinning single yarn of 40th count (English type cotton count) composed of cotton by weight and cotton;
Arrange the silver-coated filaments at m pitches
Comparative Example 1 woven at 46 lines / inch, weft at 72 lines / inch
Was obtained. At this time, the content of silver in the fabric of Comparative Example 1 was 1.0% as in Example 1.

Comparative Example 2 Using only 1.4d filaments of polyamide fibers made of nylon 6, weaving was performed at a warp of 180 filaments / inch and a weft of 90 filaments / inch so that the gap between the filaments was almost the same as in Comparative Example 1. Thus, a fabric of Comparative Example 2 was obtained.

Using the above Examples 1, Comparative Examples 1 and 2 obtained in this manner, a VHF wave (30 to 300 MHz) and a UHF wave (30
(0 MHz to 3 GHz), an electromagnetic wave shielding effect (SE) measurement test was performed by the KC method. At this time, in order to stabilize the test cloth, a cloth left overnight was used. The electromagnetic wave shielding effect (SE) was calculated from the following equation (A).

Electromagnetic wave shielding effect (%) = (1−transmitted electric field / incident electric field) × 100 (A)

The results of the measurements are shown in Table 1 below.

[0026]

As a result of the above test, the fabric of Example 1 showed
The HF wave was 99.7%, and the UHF wave was 99.3%, which proved to have an excellent shielding effect. In contrast, the fabric of Comparative Example 1 had a VHF wave of 89.2%, The UHF wave was 87.3%, and the fabric of Comparative Example 2 had a VHF wave of 80.30%.
Only 3% and 77.2% of UHF waves were cut, and leakage of electromagnetic waves of 10% or more was recognized in both cases.

[0028]

Since the fiber structure of the present invention contains short fibers coated with silver, a fiber product manufactured using these fibers exhibits a high electromagnetic wave shielding effect, and can be used in electronic equipment. It is very useful for clothing when working around, or for industrial materials where shielding of electromagnetic waves is desired, and silver contained in the fibrous structure has conductive properties. The manufactured textiles also have an antistatic function, and when used for clothing, exhibit excellent antibacterial effects against Escherichia coli, Staphylococcus aureus, MRSA, Legionella bacteria, etc. due to the action of silver. It becomes like that. In addition, the fabric of the present invention exhibits such an excellent effect in terms of function, and at the same time, since the electromagnetic wave shielding yarn is composed of a spun yarn instead of a filament, the fabric has an excellent feeling and an electromagnetic wave shielding filament. Thus, a desired effect can be obtained with a small amount of silver as compared with a cloth made of, and the effect of being able to be provided at low cost is also exerted.

[Brief description of the drawings]

FIG. 1 is a schematic view of a cross section of a spun yarn according to one embodiment of the present invention.

[Explanation of symbols]

 Reference Signs List 1 spun yarn 2 core short fiber 3 silver 4 silver-coated short fiber 5 other short fiber (other than silver-coated short fiber)

Claims (2)

[Claims] 1. The short fibers coated with silver are used in an amount of 3.
An electromagnetic wave shielding spun yarn characterized by containing more than 0% by weight. 2. The short fibers coated with silver are used in an amount of 3.
An electromagnetic wave shielding fabric comprising a spun yarn containing more than 0% by weight.