JPS6068696A - Method of producing 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 The present invention relates to a method for producing an electromagnetic shielding material coated with a conductive metal by a method such as chemical plating or electroplating.

Interference with wireless communications due to leakage of high-frequency radio waves from equipment has long been a problem, and in recent years, with the rapid spread of electronics in civilian life, this type of electromagnetic wave pollution has become an obstacle to information transmission and has been treated as a problem. Many ways to remove this are being considered. The principle behind this is to make the plastics used in electronic device housings conductive, which results in reflection and absorption of electromagnetic waves, thereby attenuating electromagnetic waves leaking outside the device. Specifically, 1d (l conductive surface film formation method, such as a method of coating with a conductive paint, a plating method, etc.) (2) a method of dispersing and compounding a conductive filler, such as carbon blank, metal powder, etc. (3) A method of laminating conductive fillers to form a composite material,
For example, methods of laminating carbon kj, @L matte, and gold copper have been proposed, and some of them have been put into practice.

However, these methods have the disadvantages of increasing costs and reducing the moldability of plastics, making them unsuitable for use in equipment. arise. Also, if you try to implement it within a reasonable cost, the electromagnetic shielding performance will be insufficient. So, next part 1
It had drawbacks such as poor durability.

The present inventors have developed a method for producing electromagnetic shielding materials using plating methods such as chemical plating and electroplating as a method for providing electromagnetic shielding properties, which does not require the special T plating method and has a good shielding effect. As a result of extensive research into providing a more durable material, we have arrived at the present invention.

That is, the present invention provides carbonates of alkaline earth metals 01 to 40
Weight part: 1. Resin 98 having a heat distortion temperature of 170°C or higher
A method for producing an electromagnetic shielding material characterized by coating a molded article obtained by forming a resin composition consisting of 9 to 20 double parts and 1 to 40 double parts of a fibrous reinforcing material with a conductive metal. It is.

Examples of alkaline earth metal carbonates include calcium carbonate,
Magnesium carbonate, strontium carbonate, barium carbonate, and double salts thereof, such as magnesium carbonate and calcium carbonate, can be used, but they can also be used to increase the adhesion between the molded body and the conductive metal and to improve the surface durability. Especially for calcium carbonate and.・/Also, it is preferable to use dolomite (magnesium/calcium carbonate).

The amount of alkaline earth metal carbonate used is 10% of the resin composition.
It is necessary to range from 01 to 40 parts by weight, preferably from 5 to 20 parts by weight. If the amount is less than 0.01 parts by weight, sufficient adhesion between the conductive metal and the molded body cannot be obtained, and if it is more than 40M parts by weight, the fluidity of the resin or resin used to obtain the molded body will be reduced.

The resin used in the present invention is 1, and has a heat distortion temperature of 170"C.
, 11. This heat distortion temperature is determined by the method specified in AFETM-D648 under a load of 1.
B, heat distortion temperature measured using 6 K4/ctr;

If the heat deformation temperature is less than 170℃, it may cause heat generation from the internal circuit when used as an electromagnetic shielding material, or defective phenomena such as deformation or foaming may occur during operations such as soldering when assembling and joining the electromagnetic shielding material. Not.

The resin used in the present invention may be either thermosetting or thermoplastic resin as long as it satisfies the above conditions.
Thermosetting resins include epoxy resin, phenol toilet seat,
Thermoplastic resins such as polyimide clothing include polyether sulfone, boria 1) V-1, polyether imide, polysulfone, polyphenylene sulfide, polyamide/imide, polyether ether ketone, polyamide, polybutylene lenticulate, etc. can be used.

Using the various resins mentioned above, a molded article of the desired shape is obtained by a molding method suitable for each resin, such as injection molding.
．． 2. Coating with a conductive metal using a known method. An electromagnetic liquid shielding material can be obtained.

The method for coating the conductive metal may be any known method, such as vacuum deposition 1. ion blating, sputtering,
Methods such as immersion in molten metal, electroplating, chemical plating, and combinations thereof are possible, and electroplating, chemical plating, and combinations thereof are preferred.

As an example, a combination of electroplating and chemical plating is used.
5. After a molded body made into a desired shape by a method such as injection molding, is subjected to pretreatment such as degreasing, etching, sensitizing, activation, etc., neutralization, and chemical plating. By electroplating a suitable metal, the surface of the molded body is coated with a metal that is effective as an electromagnetic liquid shield.

The fibrous reinforcing material may be glass fiber, carbon fiber, etc., and is necessary for reinforcing the mechanical strength of the molded article, and in some cases, metal fibers may be used for both strength reinforcement and electromagnetic shielding properties.

The amount of fibrous reinforcing material used is 1 to 40 M parts, preferably 5 to 20 M parts. If the fibrous reinforcing material is less than 1 part by weight, the reinforcing effect is insufficient, and if it exceeds 40 parts by weight, the
The surface smoothness of the molded object obtained by molding the finger composition is poor, and the adhesion of the metal film coated on the surface is reduced.

To carry out the present invention, a known method, ie, a mixer such as an extruder, is used to prepare an alkaline earth metal carbonate, a resin 2. After mixing fibrous reinforcing materials, etc. to form a cross-wire compound, a molded body is obtained by a method such as injection molding, and the surface of the molded body is coated with a metal film by an appropriate method such as the above-mentioned chemical plating or electric agate combination method. Breaks the electromagnetic shield.

The present invention will be explained below with reference to Examples.

Examples 1 to 6 The resin compositions shown in Table 1 were prepared and injection molded to give 150%
rryfn X 150 m/m X 1.5 m/
A plate of m was molded and conditioned with a conditioning solution consisting of 520 parts of sulfuric acid, 720 parts of water, and 440 parts of chromium trioxide. After washing the conditioned board with water, chemical plating and electroplating are performed according to conventional methods, and copper plating is performed to an average thickness of 30 microns to create a board whose surface is coated with copper.
A thermal cycle test to show the adhesion strength of the coating and its personnel according to the method described in No. 1-6483 and G. Woodh
The electromagnetic shielding effect was measured using the method of am et al.

The results are also listed in Table 1, and the performance as an electromagnetic shielding material was satisfied.

Comparative Examples 1-2 Copper-coated molded bodies of Comparative Examples 1-2 were produced in the same manner as in Examples 1-6 except that the components of the resin composition were changed as shown in Table IK. Next, the results were evaluated in the same manner as in Examples 1 to 6, and the results are shown in the table.

Comparative Example 1, which did not contain alkaline earth metal carbonate, had weak plating adhesion strength, poor durability even in a low-level thermal cycle test, and poor electromagnetic shielding effect. or,
Comparative Example 2 containing 50 parts by weight of alkaline earth metal carbonate had poor moldability, poor surface condition, and uneven plating adhesion. Although the measured adhesion strength was high, thermal cycle test results showed that the durability was poor, and the electromagnetic shielding effect was not satisfactory.

Example 7 Nopolanokuphenol resin was compounded with the composition shown in Table 1, and compressed into a compound, 150I']1/n]X
A plate of 150 m/m x 1.5 m/m was molded, and a copper-coated molded body was produced by the same operation as in Examples 1 to 6. Next, evaluations were made in the same manner as in Examples 1 to 6.

The results showed that the performance as an electromagnetic shielding material was satisfied.

Notes to Table 1 The bath fats shown in Table 1 are as follows.

PES: Polyether sulfone pps: Polyphenylene sulfide Plj; EK: Polyether ether carbon polyarylate:

Claims (1)

[Claims] (1) - 01 to 40 parts by weight of an alkaline earth metal carbonate,
Resin 98.9-20 with a heat distortion temperature of 170°C or higher
1. A method for producing an electromagnetic shielding material, which comprises coating a molded body obtained by molding a fatliquoring composition consisting of 1 to 40 parts by weight and 1 to 40 parts by weight of a fibrous reinforcing material with a conductive metal. (2) The method according to claim 1, wherein the alkaline earth metal carbonate is calcium carbonate. (b) The method according to claim 1, wherein the carbonate of alkaline earth gold is dolomite. (4) The method according to claim 1, wherein the alkaline earth metal carbonate is a mixture of calcium carbonate and dolomite.