JPS61269399A - Improved wood for shielding electromagnetic shield - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field] The present invention relates to improved wood that has an electromagnetic wave shielding effect.

[Conventional technology]

2. Description of the Related Art In recent years, with the development and spread of various telecommunication devices and electronic devices, there has been a strong demand for an immediate solution to problems caused by electromagnetic waves generated by these devices.

Conventionally, as a measure to prevent such electromagnetic interference, electromagnetic shielding materials such as carbon, short metal fibers, and ferrite have been used.
Attempts have been made to improve the shielding effect by using shielding materials (hereinafter simply referred to as shielding materials) in the housings of various devices. The main method for this purpose is to mix these shielding materials into various types of plastics as housing materials to reflect or absorb electromagnetic waves. but,
When using plastic mixed with conductive shielding material for the housing, it is necessary to further coat the surface with an insulating material, and when trying to form several shielding layers, there are technical issues. It involves considerable difficulty.

On the other hand, as a wooden material that has an electromagnetic shielding effect, there is a board material for equipment (Utility Model No. 58-1681) in which a shielding material made of a metal plate is interposed between a core material and a decorative material.
95), a multi-layered composite wood material made of plywood, a thin iron plate, and resin concrete, or a board made of plywood coated with resin concrete to which metal powder is added are known. However, wood materials are different from plastic materials;
Because it is difficult to mix shielding material into the material,
Conventionally, methods have been used such as bonding a metal plate to a wooden material or coating the wooden material with another material mixed with a shielding material. However, all of these involve laminations of wood and metal or other materials, and there are many problems in selecting adhesives to firmly bond dissimilar materials together.
Because it requires secondary processing such as lamination and coating, the processing process is complicated, especially when dissimilar metal plates are sandwiched between each lamination, resulting in high cost and weight. There are drawbacks.

[Problem that the invention seeks to solve]

The present invention has been made by focusing on the drawbacks of conventional wood materials imparted with an electromagnetic shielding effect, and an object of the present invention is to provide an improved electromagnetic shielding wood that can be produced with good workability, light weight, and low cost through a simple process. With the goal.

[Means for solving problems]

That is, the present invention is an improved electromagnetic shielding wood in which wood materials are bonded using one or more finely divided electromagnetic shielding materials mixed with or in combination with an adhesive.

In this configuration, the shielding material is a conductive material such as aluminum, nickel, silver, copper, brass, carbon, iron, etc. that absorbs electromagnetic waves due to electric field loss, and/or a ferrite or carbonyl iron-based material that absorbs electromagnetic waves due to magnetic field loss. These magnetically permeable substances can be made into fine powders, fibers, flakes, etc., and used alone or in combination. They can be selected as appropriate. When these shielding materials are mixed or used together with adhesives, they must not affect the adhesive strength of the adhesive and must have sufficient electromagnetic shielding effects. The particle size of the material is approximately 10 to 300
μm, thin diameter about 50-10, OQOIlm, preferably particle size 50-200 μmS thin diameter 500-5,000. czm
Also, for fibrous shielding materials, the fiber diameter is 5 to 300.
μm, preferably 20 to 100 μm, fiber length 0.5 to 2
Finely divided short fibers of 0n, preferably 1 to 10n are preferably used.

However, in order to efficiently obtain a shielding effect with a small amount of addition, it is preferable to use flakes or fibers rather than powders.

Further, the adhesive is not particularly limited, and any adhesive that is conventionally used for bonding wood materials may be used. Further, depending on the type of adhesive, a known hardening agent or extender may be appropriately added, and a preservative and insect repellent to protect the wood material from decay and insect damage may also be appropriately added.

Furthermore, there are no particular restrictions on the types of improved wood produced by bonding various wood materials together using adhesives; for example, various types of plywood obtained by bonding veneers, laminated wood (
LVL), laminated wood obtained by laminating sawn boards, particle board obtained by joining small pieces of wood material, etc. can be cited as typical improved wood materials.

Next, as a method for manufacturing the electromagnetic shielding improved wood of the present invention, a method of uniformly mixing and dispersing a shielding agent in an adhesive in advance and bonding wood materials by a conventional method to produce the various improved wood materials described above; Alternatively, with adhesives such as urea resins and melamine urea resins that cure and bond by adding a curing agent, a shielding material is added at the same time when the adhesive and curing agent are mixed and applied to the wood material. This can be achieved by, for example, a method of bonding wood materials to produce improved wood.

In this case, the ratio of the shielding material mixed or added to the adhesive cannot be unconditionally defined because it varies greatly depending on the material, shape, purpose of use, etc. of the shielding material, but it is approximately 1 to 80 parts by weight per 100 parts by weight of the adhesive. The range is in parts by weight, and the distribution amount of the shielding material per adhesive layer by the adhesive is in the range of about 10 to 1.000 g10f.

Furthermore, when manufacturing plywood or laminated materials by gluing multiple veneers together, by using an adhesive blended with different types or distributions of shielding material for each adhesive layer,
It can be appropriately adapted to the wavelength, intensity, etc. of the electromagnetic waves to be shielded.

〔Example〕

Example 1 The thickness of the veneer was 0.65 m, 1.4 m, and 0.65 m, respectively.
Three sheets of lauan material each having an area of 30cm x 30c+n were used, and 31g of steel short fiber shielding material was used in combination with an adhesive and a hardening agent for each layer to have the composition shown in Table 1.
Applied, 10kg/c1! After applying cold pressure for 20 minutes at a pressure of I got it. In the figure, 1 is the thickness 1.
4fl veneer, 2 a veneer each having a thickness of 0.65 mm, and 3 an adhesive layer containing a shielding material.

Table 1 Example 2 A shielding material having the composition shown in Table 2, using a lauan plywood core material with an area of 30 cm x 30 cm and a thickness of 2.5 fi, and two decorative veneers of cypress wood with a thickness of 0.7 m. 23g of mixed adhesive was applied for each layer and 10g was applied at a pressure of 5kg/Cj.
Time-pressing was performed to obtain the electromagnetic shield decorative plywood B of the present invention shown in FIG. In the figure, 4 is lauan plywood,
5 indicates a decorative veneer, and 6 indicates a shielding material mixed adhesive layer.

Table 2 Example 3 230 g of wood chips was sprayed with 30 g of urea resin adhesive mixed with 40% by weight of short brass fibers, and 5. / aJ
After temporary compaction for 1 minute under the pressure of
An electromagnetic shielding particle board of the present invention of X30Cffi was obtained.

In FIG. 3, reference numeral 7 indicates a wood chip, and reference numeral 8 indicates an adhesive containing a shielding material.

Test Examples Plywood A and B manufactured in Examples 1 and 2, ordinary plywood manufactured in the same configuration as plywood A and B using an adhesive without adding shielding material, and plywood of the present invention manufactured in Example 3. Regarding particle board, frequency 50 to 500 was measured using a plastic shielding material testing machine manufactured by Takeda Riken Kogyo ■.
The results of comparing the shielding effects in the MH2 range are shown in Table 3, and it was found that the plywood and verticle board of the present invention had sufficiently satisfactory shielding effects.

Table 3 [Effects of the Invention] As is clear from the structure and examples described in detail above, the electromagnetic shielding improved wood of the present invention has good workability using only the primary processing means that is almost the same as that of conventional improved wood such as plywood. , and without impairing the characteristics such as water absorption and desorption properties, texture, etc. peculiar to wood materials (it can be easily manufactured), and it can be provided at low cost because it does not require complicated processes such as coating the surface with insulation. In addition, in improved wood products such as plywood, LVL, etc., which are manufactured by laminating multiple sheets of flat wood materials, the adhesive layer of each layer may contain a shielding material that has different electromagnetic wave reflection or absorption characteristics. Even when using the same shielding material, by appropriately adjusting the amount of shielding material added to each adhesive layer, it can be used in combination with a wide range of electromagnetic wave wavelengths, intensities, etc. Correspondingly, it is possible to provide a high shielding effect.Also, some electromagnetic wave shielding materials that cannot be formed into a plate shape or the like and which are conventionally difficult to use can be used with the shielding improvement of the present invention. Wood has the advantage of being extremely easy to apply.

[Brief explanation of drawings]

Fig. 1 is a perspective view showing one embodiment of the electromagnetic shielding improved wood of the present invention, Fig. 2 is a perspective view showing an embodiment of the same, Fig. 3
The figure shows a perspective view of the electromagnetic shielding particle board of the present invention. 1.2... Single plate, 3... Adhesive containing shielding material, 4
... core material, 5 ... decorative veneer, 6 ... adhesive containing shielding material, 7 ... wood chip, 8 ... adhesive containing shielding material. Fig. 1/IS7# Melo↓ ノ・°～dried Kurneet'

Claims (1)

[Claims] 1. An improved electromagnetic shielding wood, characterized in that wood materials are bonded using one or more finely divided electromagnetic shielding materials mixed with or in combination with an adhesive.