JPH0260497B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application The present invention relates to an electromagnetic wave shielding material that can be seen through and has an electromagnetic shielding effect, and more specifically,
The present invention relates to an electromagnetic wave shielding material that has excellent transparency, less deformation such as warping and bending, and less occurrence of internal distortion, and is also excellent in various resistances.

Prior Art and Technical Problems of the Invention In recent years, with the advanced development of office automation equipment and other electronic devices, electromagnetic wave shielding effects have been developed to prevent noise in electronic devices and to prevent direct effects of electromagnetic waves on the human body. , transparent electromagnetic shielding plates are required for CRT filters in office automation equipment and viewing windows in shielded rooms for electronic equipment.

Conventionally, such transparent electromagnetic wave shielding plates include: porous metal plates such as punched metal; articles in which transparent materials are coated with conductive metal oxides or metals by vacuum deposition; conductive synthetic fiber networks themselves; stainless steel. wire mesh; etc., but the shielding effect tends to deteriorate over time due to corrosion etc., and it is difficult to obtain a sufficient shielding effect, and wire mesh is relatively easy to obtain, but the strength is insufficient and It has drawbacks such as it is difficult to clean the torn, corroded and attached dirt, and it is difficult to obtain a filament with a small diameter.

Outline and Object of the Invention The present inventor selected a resin mainly composed of diethylene glycol bisallyl carbonate among various resins and a metal-plated synthetic fiber gauze among various porous conductive members, and added the metal-plated synthetic fiber gauze to the resin molded body. It has been found that by embedding metal fiber gauze, it is possible to obtain an electromagnetic wave shielding material that has excellent transparency, is free from warpage, bending, and other changes, and has excellent resistance to various types.

That is, an object of the present invention is to provide an electromagnetic wave shielding material that eliminates the above-mentioned drawbacks of conventional electromagnetic wave shielding materials.

Another object of the present invention is to have excellent transparency and electromagnetic wave shielding properties, eliminate deformation during molding, and
Moreover, it has heat resistance, chemical resistance, abrasion resistance, stain resistance,
It is an object of the present invention to provide a see-through electromagnetic wave shielding material that is excellent in various resistances such as arc resistance.

Still another object of the present invention is to provide a resin-conductive network transparent electromagnetic wave that effectively eliminates deformations such as warping and bending that occur when diethylene glycol bisallyl carbonate resin is used, as well as cracks due to internal distortion. To provide shielding material.

Structure of the Invention According to the present invention, there is provided a transparent electromagnetic wave shielding material characterized in that at least one sheet of metal-plated synthetic fiber gauze is embedded in a synthetic resin molded body mainly composed of diethylene glycol bisallyl carbonate.

The diethylene glycol bisallyl carbonate unit can be present in the synthetic resin unit in an amount of 50 to 100% by weight, and metal-plated synthetic fiber gauze having a mesh size of 80 to 250 meshes is advantageously used.

Preferred Embodiment of the Invention In FIG. 1 showing the cross-sectional structure of the electromagnetic wave shielding material of the present invention, this shielding plate 1 is integrally molded with diethylene glycol bisallyl carbonate resin 2, and there is a gap between one surface 3 and the other surface 4. A metal-plated synthetic fiber gauze 5 is embedded in the metal-plated synthetic fiber gauze 5, and the two resins partitioned by this metal-plated synthetic fiber gauze are the gauze 5.
are connected and integrated through the openings of the two.

As shown in FIG. 2, the electromagnetic wave shielding material 1 of the present invention has spacers or gaskets 8, 8 in the center of sheet-like molds 6, 7 made of, for example, tempered glass, which can follow shrinkage during polymerization and curing. The metal-plated synthetic fiber gauze 5 is fixed in a liquid-tight manner through the space 9, a composition containing diethylene glycol bisallyl carbonate and a radical polymerization initiator is injected, and this composition is polymerized and cured under heating. It is obtained by

The diethylene glycol bisallyl carbonate used in the present invention has the following formula: It has a chemical structure represented by This monomer has two allyl groups that can be polymerized by a radical initiator, and is characterized by forming a three-dimensional networked thermosetting polycarbonate by polymerization and curing. Due to this feature, the molded bodies according to the invention not only have the advantage of being essentially colorless and transparent, but also have good heat resistance, chemical resistance, abrasion resistance,
It has the effect of being essentially excellent in various resistances such as stain resistance, weather resistance, and arc resistance.

As the resin monomer component, it is preferable to use diethylene glycol bisallyl carbonate alone, but other monofunctional ethylenically unsaturated monomers such as methacrylic acid ester, It is also possible to use acrylic ester, styrene, etc. in combination. As a radical initiator, t-butyl peroxyneodecanoate,
Diisopropyl peroxydicarbonate, t-
Organic peroxides such as butyl peroctoate are used, generally 1 to 5% by weight based on the monomer components.
Use in the amount of The polymerizable curable composition used in the present invention may of course contain additives known per se, such as colorants, antioxidants, surfactants, mold release agents, ultraviolet absorbers, etc., within the scope of the spirit of the present invention. Can be blended within.

In the present invention, metal-plated synthetic fiber gauze is used in combination with the resin described above. The metal-plated synthetic fiber gauze is obtained by weaving or knitting monofilament, multifilament yarn or spun yarn of polyester, nylon, vinylon, acrylic, etc. into a coarse weave, and adding copper, nickel, or cobalt to the gauze fabric obtained by weaving or knitting monofilament, multifilament yarn, or spun yarn such as polyester, nylon, vinylon, or acrylic into a coarse weave. A plating layer of metal such as chromium, silver, or aluminum is used. The plating layer can be formed by electroless plating (chemical plating),
This can be done by vacuum deposition or a combination of these and electroplating. The plating layer may be formed to such an extent that these surfaces become sufficiently conductive but do not cause clogging. The plating layer may be a single metal layer or may be composed of a plurality of metal layers, for example, a combination of an electroless plating layer and an electrolytic plating layer is used. The metal-plated synthetic fiber gauze used in the present invention has a mesh size of 80 to 250,
In particular, it is desirable to have a mesh of about 100 to 200 meshes from the viewpoint of electromagnetic wave shielding properties and light transmittance, and the aperture ratio is generally 10 to 90%, especially 30%.
It is desirable that it be in the range of 80% to 80%.

According to the present invention, by using metal-plated synthetic fiber gauze as the conductive net, extremely large advantages can be achieved in relation to molding shrinkage of the resin and the like. In other words, the molding shrinkage rate of diethylene glycol bisallyl carbonate is approximately 14%, but when using metal nets, punched metal, etc., the resin shrinks less in the areas where the conductive net is provided, and the resin shrinks in other areas. As a result of this contraction, internal strain or internal stress occurs. For example, in areas where the conductive network is offset from the center of the resin molded body,
Deformations such as warping and bending easily occur. Furthermore, during use or when exposed to heat, cracks are likely to occur and transparency may be impaired. On the other hand, according to the present invention, even when producing a relatively large-sized molded object, the synthetic fibers that form the base of the conductive network have flexibility and easy deformability, so that they are resistant to shrinkage during resin curing. It has good followability and effectively prevents deformations such as warping and bending during molding, the generation of internal stress and strain, and the occurrence of cracks accompanying these.

Moreover, with synthetic fibers, monofilaments with small diameters can be easily obtained, and the strands of the conductive network themselves can be made extremely fine.
When used for equipment, CRT filters, etc.
You can obtain something that is transparent and does not cause any discomfort (or eyesore).
Further, this metal-plated synthetic fiber gauze itself has good workability such as cuttability, and the molded article in which it is embedded also has good workability. Furthermore, this material also has the advantage of good followability during bending.

In the electromagnetic shielding material of the present invention, since the metal-plated synthetic fiber gauze has good shrinkage followability, the position where it is buried is not particularly limited; for example, it may be located in the center of the molded body, or it may be placed in any It may be provided offset to the surface side. Furthermore, two or more sheets of metal-plated synthetic fiber gauze can be provided if desired. The metal plating layer may be colored if desired. Furthermore, in order to improve the adhesion with the resin,
The surface of the metal-plated synthetic fiber gauze may be previously treated with a silane coupling agent such as triethoxyaminopropylsilane. Further, it may be dyed black for the purpose of removing metallic color.

Polymerization curing is generally carried out at a temperature of 60 to 150°C.
It can be carried out in one stage or in multiple stages over a period of 0.5 to 5 hours.

The electromagnetic wave shielding material according to the present invention not only has excellent electromagnetic wave shielding function and can be seen through, but also because the manufacturing method is the cell cast method, it is completely integrated with the conductive net, and can be bonded by welding or adhesive. There is no risk of peeling or fine void distortion of the image, which is the case with conventional products. In addition, by using diethylene glycol bisallyl carbonate as the molding resin, it has superior scratch resistance compared to other transparent resins such as acrylic, and has other properties such as chemical resistance, heat resistance, arc resistance, etc. It has the potential to withstand use under more special conditions. Also, since it is made of resin, it can easily provide functions other than electromagnetic wave shielding, such as UV protection.

In addition, by forming a plate in which conductive fiber gauze is embedded in diethylene glycol bisallyl carbonate resin, which has excellent resistance to various conditions, the above-mentioned problems such as corrosion and tearing of the mesh can be solved, and cleaning is also easy and the overall appearance is uniform. This provides an electromagnetic wave shielding material that does not cause discomfort when used as a CRT filter for office automation equipment.

Example An electromagnetic wave shielding plate was manufactured using the mold shown in FIG.

An electromagnetic wave shielding net made of 200 mesh polyester fiber monofilament gauze coated with copper in a non-clogging state is placed under uniform tension. Next, a gasket was placed on each peripheral edge of two 400 m/m square glass plates, and the electromagnetic shielding net was sandwiched between the two glass plates, which were then clipped to form a gap of 3 m/m.

Dissolve 3% by weight of diisopropyl peroxydicarbonate in diethylene glycol bisallyl carbonate monomer, inject it through the injection hole provided at the top of the gasket, and heat and cure under the conditions shown below to achieve the desired temperature 45℃ 3hr 50 2 55 2 60 2 65 2 70 1 75 1 80 1 90 0.5 100 0.5 A molded article was obtained.

The obtained electromagnetic wave shielding plate had no deformation such as warping or bending, had excellent transparency, and was completely unobtrusive when used as a filter.

Effects of the Invention According to the present invention, by using metal-plated synthetic fiber gauze as a conductive network for the diethylene glycol bisallyl carbonate resin molded body,
The present invention provides an electromagnetic wave shielding material that effectively prevents deformations such as warpage and bending, and the generation of internal distortion and internal stress during molding, and furthermore has excellent transparency, no image distortion, and excellent resistance to various types of electromagnetic waves.

[Brief explanation of the drawing]

FIG. 1 is a sectional view of a transparent electromagnetic shielding material according to the present invention, and FIG. 2 is an explanatory diagram for explaining the production of the electromagnetic shielding material of the present invention. 1 is an electromagnetic wave shielding material, 2 is diethylene glycol bisallyl carbonate resin, 3 and 4 are surfaces, 5
6 and 7 are molds, and 8 is a gasket, respectively.

Claims (1)

[Scope of Claims] 1. A transparent electromagnetic wave shielding material characterized in that at least one sheet of metal-plated synthetic fiber gauze is embedded in a synthetic resin molded body mainly composed of diethylene glycol bisallyl carbonate. 2. The shielding material according to claim 1, wherein the metal-plated synthetic fiber gauze has a mesh of 80 to 250 meshes. 3 A composition containing a monomer mainly composed of diethylene glycol bisallyl carbonate and a radical polymerization initiator is injected into a mold in which metal-plated synthetic fiber gauze is spread and fixed in the inner space, and the composition is polymerized and cured. The shielding material according to claim 1 obtained by the above method.