JPS58188191A - Electromagnetic wave shielding material - 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] This invention prevents electromagnetic waves generated from electrical equipment with contacts, commutator motors, discharge tubes, microwave ovens, high-voltage power lines, railways, automobiles, wireless communication equipment, computers, etc., from being radiated to the outside. The present invention relates to an electromagnetic wave shielding material that prevents harmful effects such as disturbances in television picture quality, radio noise, computer malfunctions, etc. by blocking the intrusion of electromagnetic waves generated from these things.

Conventionally, electromagnetic wave shielding materials using metal plates and electromagnetic wave shielding materials in which metal is fully vapor-deposited, welded, and painted on the inside and outside of plastic to completely prevent the radiation of TMI waves to the outside or the intrusion of electromagnetic waves from the outside have been developed. Although there are shielding materials, the former has high processing costs, low productivity, is not suitable for complex shapes, and has the disadvantage that the shielding material has a high possibility of becoming a source of electromagnetic waves. The latter (in this case, processing costs are high and it is not suitable for rough shapes, and there are problems with adhesion strength, causing metal pieces to peel off during use, or because the conductive metal film on the entire surface of the casing is present) There were drawbacks such as the need to take separate insulation measures.

Therefore, an electromagnetic shielding material made of polypropylene or other thermoplastic resin (completely mixed with aluminum flakes and injection molded) has been proposed to eliminate all of these drawbacks, but resin (2)
Since the aluminum flakes (1) are mixed and stirred and then injection molded, the aluminum flakes (1) are oriented in various directions as shown in Fig. 1, and are not distributed in layers, and during stirring, one of the aluminum flakes is Since the parts are shattered, electromagnetic waves can pass through, making it difficult to sufficiently shield electromagnetic waves.

This invention was made with the above-mentioned points in mind, and the gist of the invention is that the cellulose all-condensed ammonium phosphate is soaked in a solution containing urea, stirred, and left for a certain period of time. Metal flakes and a thermosetting resin are mixed into the material that has been pre-dried and esterified to make it non-combustible, and this is then molded into paper. This is an electromagnetic wave shielding material that is made by press-molding it under heat and then press-molding it under heat.

An embodiment of the present invention will be described below based on the drawings.

Ammonium phosphate is a complete mixture of phosphoric acid and urea.
When heated above O'C to cause a reaction, thermal decomposition of urea and tF4 occur.
Ik3 combination of acids occurs and condensed ammonium phosphate is entirely produced. Phosphoric acid/and urea tI 1 Add a small amount of water and heat.
When urea is dissolved in phosphoric acid, water vapor and carbon dioxide are completely generated at 100''C, and upon further heating, a condensation reaction begins at /3S''C and ammonia gas is generated. A 110% additive solution by adding urea to the condensed ammonium phosphate produced here? to make. For example, 89% H3PO4: (NH2)200 = 1
: 4 i.e. H3P04 (89%)t″SSO
(NH city 00 is 1200g.) In this solution, stir the bulb, cellulose made of waste paper or cellulose made of wood powder such as saw bream, coconut shell, walnut shell, rice shell etc. After leaving for about 72 hours, the solution was squeezed so that the solution was about twice the weight of the cellulose, and pre-dried at 90 to 10'C until the weight was about 7.3 times the weight of the cellulose. The mixture was heated to "C" and the reaction was carried out for 75 minutes.

This esterified cellulose TTM becomes flammable. The metal flakes and thermosetting synthetic resin are all mixed into this, and a dispersant is added so that the metal flakes are evenly dispersed, followed by paper-making. In addition, the ratio of cellulose to gold [7 lakes and thermosetting resin is cellulose, /L00 to metal flakes (if all aluminum flakes are used as metal flakes) is 70~! ;
01 thermosetting resin 70 to 50 is desirable. When the paper is then press-molded into a plate shape or any box shape during paper-making, the mixed thermosetting resin dissolves in the acid and becomes a strong plate or box shape.

As shown in Figure 2, the electromagnetic wave shielding material produced as described above has the mixed metal flakes (3) lined up in an orderly manner over the entire surface in the same direction, and is distributed in layers, so it completely blocks the transmission of electromagnetic waves. It has excellent blocking effect. Furthermore, since the cellulose esterified as described above is flame retardant, it is used in safety devices, cabinets of electrical equipment, and the like. Since it is easy to manufacture and the main materials used are fibers such as pulp, waste paper, sawdust, and coconut shells, it can be provided at a very low cost.

[Brief explanation of the drawing]

Figure 1 shows conventional resin with aluminum flakes? Mixed injection molded electromagnetic shielding material? Figures 1 and 2 are diagrams showing all of the electromagnetic wave shielding materials related to this emission. (3 doors...metal flakes. Patent applicant Meisei Chemical Industry Co., Ltd.°: !晟小′ Figure 2 3

Claims (1)

[Claims] Cellulose made from wood powder such as pulp, waste paper, sawdust, coconut shells, walnut shells, rice husks, etc. is pickled in a mixture of condensed ammonium phosphate with urea added, left for a certain period of time, and then the cellulose is mangled. An electromagnetic wave shielding material characterized in that it is esterified by squeezing and pre-drying, mixed with metal flakes and thermosetting resin gold, formed into paper, and then press-molded under heating.