JP2518954Y2 - Knitting for electromagnetic shield - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial field of application] The present invention relates to an electromagnetic shield knitted fabric used for shielding electromagnetic fields.

[Prior Art] In recent years, various devices using electronic parts such as microcomputers, for example, electronic typewriters, office machines such as printers, household electric devices such as washing machines and vacuum cleaners, and fuel injection control are electronically controlled. With the rapid spread of automobiles and the like, the number of microcomputers used and the clock frequency are increasing.

As a result, the electromagnetic noise generated by the electronic component rides on the peripheral signal line or the like through the gap of the housing that houses each electronic component, or the electromagnetic noise from the outside directly affects the signal line and the electronic component, This may cause malfunctions in electronic components and various devices.

Therefore, conventionally, for the purpose of shielding electromagnetic noise, a metal gasket made of a good conductive metal, an elastomer gasket in which a conductive material is added to the elastomer, or a mesh gasket in which the elastomer is covered with a metal wire mesh is used. ing. Alternatively, an electromagnetic shield is provided by winding a wire mesh around a metal mesh.

Among them, the metal mesh using the metal wire is used in various places because the shape to be used is not limited.

[Problems to be Solved by the Invention] However, when the above metal mesh is used, the following problems are not always preferable.

For example, in the case of a mesh gasket, there is a problem in that a permanent strain is generated in the metal mesh during compression, the elasticity of the elastone is impaired, and the electromagnetic shielding property is deteriorated.

Also, when winding the metal mesh directly on the electric wire,
There is a problem that the metal mesh deteriorates due to rust or the like depending on the use environment.

Furthermore, since this metal mesh uses metal as a material, there are restrictions on the method of forming the mesh,
There is a problem that the mesh cannot be flexibly formed like the case where the cloth is formed from the normal fibers, and the mesh is separated during use.

An object of the present invention is to solve the above problems and to provide a knit for an electromagnetic shield which does not disintegrate or rust during use and does not deteriorate in electromagnetic shielding property.

[Means for Solving the Problems] The present invention made to achieve the above-mentioned object is to provide an ultrafine powder of a refractory metal and / or a compound of the metal, which is produced by a vapor phase method by thermal decomposition of hydrocarbons. While using a yarn in which carbon fibers grown as a growth start portion and other synthetic fibers or natural fibers are twisted together, the content of carbon fibers in the yarn is set to 15 to 60% by weight, and the yarn is The gist is a knitted fabric for electromagnetic shielding, which is formed by knitting.

Here, unlike the polyacrylonitrile-based carbon fiber or the pitch-based carbon fiber, the carbon fiber is formed in a whisker shape having a minute diameter substantially equal to the diameter of the ultrafine powder of the refractory metal and / or its compound. .

The refractory metal used in the present invention is a metal that does not vaporize at a temperature of 950 to 1300 ° C., which is the temperature of pyrolysis of hydrocarbons, and is a group 4a group of the periodic table such as Ti and Zr, V and Nb, etc. Group 5a, C
6a group such as r and Mo, 7a group such as Mn, and 8 group element such as Fe and Co are suitable, and Fe, Co, Ni, V, Nb, Ta, Ti and Zr are particularly preferable.
Is. And, such metal compounds include oxides, nitrides, and other salts thereof.

Further, as the material of the thread other than the carbon fiber, it is possible to use an ordinary synthetic fiber material such as polyacryl, polyester, polyamide, glass fiber or the like, but other than that, for example, cotton, hemp, silk or the like can be used. Natural fibers may be used.

[Operation] The knitted fabric for electromagnetic shielding of the present invention uses a so-called blended yarn in which the above-mentioned carbon fiber and other synthetic fiber or natural fiber are twisted together as a yarn constituting the knitted fabric, and the blended yarn is knitted to form an electromagnetic wave shield. To form a knitted fabric.

Therefore, since it has flexibility, it can be knitted into an arbitrary shape, and the knitted product will not be scattered or rusted, and a good electromagnetic shield can be performed for a long period of time.

Further, the above-mentioned carbon fiber is excellent in mechanical properties such as tensile strength, which is a characteristic peculiar to carbon fiber, based on its regular graphite crystal layer, so that the strength of the yarn, and thus the strength of the knitted product is improved.

[Embodiment] An embodiment of the present invention will be described below with reference to the drawings. FIG. 1 shows a knit 1 for electromagnetic shielding to which the present invention is applied.

As shown in the figure, the electromagnetic shield knitted fabric 1 is formed by using a mixed yarn 4 formed by twisting thin synthetic fibers 2 and carbon fibers 3 and knitting the mixed yarn 4.

As the synthetic fiber 2, for example, polyacrylic, polyester, polyamide, glass fiber or the like is used, and as the carbon fiber 3, fiber having a diameter of 0.1 to 0.5 μm and a length of 0.1 to 1 mm is used.

The content of the carbon fibers 3 contained in the blended yarn 4 may be in the range of, for example, 15 to 60% by weight, preferably 25 to 50% by weight, and the electrical resistivity of the electromagnetic shield knit 1 at this time is It is less than 0.10 to 0.15 Ω · cm and its physical properties are not impaired.

And when manufacturing the above-mentioned knit 1 for electromagnetic shielding, it is performed as follows.

First, in a furnace at 950 to 1300 ° C, a carbon phase fiber having a diameter of 0.1 to 0.5 μm and a length of 0.1 to 1 mm is used as a growth initiator using iron powder having a particle diameter of 0.02 to 0.03 μm by a vapor phase method of thermally decomposing benzene. Grow 3 The carbon fiber 3 has the following physical properties.

Tensile strength: 200 kg / mm ² Elasticity: 20 t / mm ² Volume resistivity: 0.001 Ω · cm Next, the carbon fiber 3 and the synthetic fiber 2 are twisted together to produce a mixed yarn 4. Then, the knitted fabric 1 for electromagnetic shielding of the present embodiment is manufactured by knitting the mixed yarn 4 by, for example, flat knitting.

The electromagnetic shield knit 1 produced in this manner is
Since the carbon fiber 3 is contained in the knitted blended yarn 4, the carbon fiber 3 is electrically conductive and therefore exhibits a good electromagnetic shielding property.

Further, since the mixed yarn 4 is formed of the carbon fiber 3 and the synthetic fiber 2, it is easy to knit,
Moreover, it has a higher degree of freedom in braiding than metal and can be knitted into a complicated shape.

Further, this electromagnetic shield knit 1 is highly flexible, and when it is placed around the elastomer member of the gasket, for example, the elastomer member is immediately returned to its original state even if it is pressed and dented. There is no loss of sex.

Moreover, since the electromagnetic shield knitted fabric 1 can be knitted tightly, it does not easily come apart during use and does not rust.

Although the embodiments of the present invention have been described above, the present invention is not limited to such embodiments, and it is needless to say that the present invention can be implemented in various modes without departing from the scope of the present invention. .

For example, on the surface of the carbon fiber 3, nickel,
Copper, silver, chrome or the like may be plated, and well-known vacuum deposition, electrolytic plating, electroless plating, coating, etc. can be used as the method of plating.

[Effects of the Invention] As described in detail above, since the electromagnetic shield member of the present invention is knitted using a mixed yarn of carbon fibers and other fibers, it has a high electromagnetic shielding property and may rust. Absent. Moreover, since the braid can be tightly knitted, the electromagnetic shield can be excellently performed for a long period of time without being loosened during use. Further, since it is more flexible than that of the conventional metal, it can be easily manufactured in any shape, and the elasticity of the gasket is not impaired even when used around the gasket.

[Brief description of drawings]

FIG. 1 is a plan view showing a knitted fabric for electromagnetic shielding according to an embodiment of the present invention. 1 ... Electromagnetic shield knit, 2 ... Synthetic fiber, 3 ...
Carbon fiber

Claims (1)

(57) [Scope of utility model registration request] 1. A carbon fiber, which is produced by a vapor phase method by thermal decomposition of hydrocarbon and is grown by using an ultrafine powder of a refractory metal and / or a compound of the metal as a growth start portion, and another synthetic fiber or A knitted fabric for an electromagnetic shield, which is formed by knitting a yarn in which a yarn in which natural fibers are twisted together is used and the content of carbon fiber in the yarn is 15 to 60% by weight.