JPS61219642A - Electromagnetic shield laminate - 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 an electromagnetic shielding material, and particularly to an electromagnetic shielding material using a conductive polymer.

1st month For various electronic devices including computers.

ICs, LSIs, etc. are used, but the electromagnetic waves of high-frequency pulses generated there leak to the outside and have a large impact on peripheral devices.

Conventionally, two main methods have been considered as so-called EMI countermeasures in equipment casings to prevent leakage of electromagnetic waves from such electronic equipment to the outside.

One is a surface treatment method that forms a conductive film on the surface of a plastic molded product, and the other is a molding method for a composite plastic conductive agent that mixes a conductive filler into the plastic.

However, in the former surface treatment method, for example, when using metal plating, the types of resin that can be plated are limited, and when using metal foil tape, it is not sufficient in terms of weight reduction, and Although it is conceivable to use a conductive paint, there are drawbacks such as not being able to obtain a homogeneous paint film unless it is applied to a thickness of 50 μm or more, and a sufficient shielding effect cannot be obtained.

Moreover, in the latter molding method, it is necessary to mix 30 to 40% filler, so there is a problem that a product with high mechanical strength cannot be obtained.

On the other hand, it is known that polymers with conjugated double bonds in their main chains, such as polyacetylene, polythiophene, and polypyrrole, have electrical conductivity comparable to that of metals when doped with trace amounts of impurities; ,
It has not been put into practical use because it has poor stability in air, cannot maintain its metallic state for a long time, and lacks sufficient mechanical strength.

The present invention in X1101 was made in order to solve the above-mentioned drawbacks, and it is an object of the present invention to provide a lightweight and strong electromagnetic shielding material that does not have such drawbacks.

As a result of various studies conducted by the present inventors, it was discovered that a pyrrole-based polymer complex electrochemically polymerized in the presence of an aromatic anion has excellent properties such as mechanical strength. This led to the present invention.

That is, the present invention relates to an electromagnetic shielding material having a layer mainly composed of a polymeric complex of an aromatic anion and a pyrrole monomer.

More specifically, the electromagnetic shielding laminate of the present invention has a structure in which pyrrole or a derivative thereof is electrolytically polymerized in the presence of a salt of an unsubstituted or substituted aromatic anion, It usually has a layer of a polymeric complex containing anions as a main component, usually in the form of a film.

By placing a layer of such a pyrrole polymer complex on a support selected according to the purpose.

A laminate of the present invention can be obtained.

The pyrrole-based polymer complex used in the present invention is produced by placing a solution in which a pyrrole-based monomer and an anion salt are dissolved in a solvent into a predetermined electrolytic cell, and then subjecting it to an electrolytic polymerization reaction by anodic oxidation.

The pyrrole monomer used in the present invention is not particularly limited, but for example, in addition to pyrrole, 3,4-alkyl (carbon number: 1 to 4) pyrrole, 3,4-arylpyrrole, 3(or 4) Alkyl-4 (or 3)-arylpyrrole (carbon number: 1 to 4).

The content of pyrrole or its derivative in the electrolytic solution can be selected as appropriate, but is usually preferably 0.02 to 1.00 mol, and particularly effective 0.10 to 0.30 mol.

If it is less than 0.02 mol, the film forming efficiency will be low, while if it is 1.00 mol or more, it will be difficult to obtain a uniform film.

Furthermore, as the unsubstituted or substituted aromatic anion which is a constituent component of the present invention, various types can be used, including the same or different substituents selected from hydrogen, lower alkyl (C number: 1 to 3), nitro, or cyanide. Preference is given to using the respective anions of at least one substituted aromatic sulfonic acid or likewise substituted aromatic carboxylic acids; particularly good results are obtained with the anion of parasulfonic acid.

In addition, this anion is not only one type in the polymer complex, but also
Two or more types may be included if necessary. Further, this anion is usually used as a metal salt in addition to at least one kind of reaction solution, and the cation in this case includes, for example, alkali metals such as Li, Na, and (Et
) N , (Bu) N, ammonium, H, and the like.

What is the content of aromatic anion metal salts in the electrolytic solution?

Although it can be selected as appropriate, it is usually preferably 0.01-0.2 mol. If it is less than 0.01 mol, the polymerization efficiency will be poor, and if it is 0.2 mol or more, undissolved electrolyte will be dispersed in the membrane, resulting in a decrease in mechanical strength.

Examples of solvents used in producing the pyrrole polymer complex layer of the electromagnetic shielding laminate of the present invention include water, methanol, acetonitrile, and benzonitrile.

Propylene carbonate, γ-butyl lactone, nitrobenzene, dioxane, dimethylformamide.

Mention may be made of polar solvents such as acetone. From the point of view of reactivity, acetonitrile, benzonitrile, and propylene carbonate are preferable.Furthermore, not using water or containing water in the solvent tends to result in a more homogeneous polymer complex and a film with high tensile strength. be.

The pyrrole-based polymer complex used in the present invention is produced by placing a solution in which the above-mentioned pyrrole-based monomer and aromatic anion salt are dissolved in a solvent into a predetermined electrolytic cell, and then performing an electrolytic polymerization reaction by anodic oxidation. Ru. If you need more,
Additives such as catalysts may also be added.

There are no particular restrictions on the structure or shape of the electrolytic cell and the electrodes placed therein, and those commonly used in the field of electrolysis technology can be applied.For example, rotating disk electrodes or multilayer electrodes can also be used, and the anode and Materials constituting the 6 electrodes that can be used include those in which the cathode is isolated by a porous membrane made of glass, polymer, etc. For example, Au
, Pt, Ni and other metals, their oxides, SnO, In
These composite electrodes or coated electrodes can be mentioned, and it is particularly preferable to use a metal oxide for the anode because a strong film of the polymer complex can be obtained.

The electric current applied during the electrolytic reaction affects the homogeneity of the mono-reactive mono-polymer complex, the strength or thickness of the membrane, so it is necessary to adjust it appropriately according to the required quality of the product. Usually, it is preferable to set the current to at least 0.1 to 1.5 mA. It seems that when it is set within this range, it becomes easy to polymerize and has strong strength.

Although the bonding state between the pyrrole monomer and anion constituting the pyrrole polymer complex obtained in this way is not exactly clear, as far as the present inventors have analyzed, it is clear that the pyrrole polymer is the main component. It is considered that a complex is formed on the polymer chain in a ratio of about 3/1 of the pyrrole monomer/anion in molecular units.

Although there are various configurations of the electromagnetic shielding laminate of the present invention depending on the purpose, typical configuration examples will be described below with reference to the drawings.

1 to 4 show examples of use as an adhesive tape or adhesive film, and FIG. 5 shows an example of use as a box-like structure.

The laminates shown in FIGS. 1 and 2 have a pyrrole polymer complex layer 3 formed on an adhesive layer 2. For example, after coating the above layer film with something like acrylic emulsion as adhesive.

Manufactured by laminating with release paper.

The laminates in FIGS. 3 and 4 have adhesive layer 2 in FIG.
It was made in the same manner except that a conductive filler 4 such as carbon or fine metal powder was dispersed therein, and it has not only an electromagnetic shielding effect but also an electrostatic shielding effect.

In FIG. 4, a protective layer 5 is further formed on the pyrrole polymer complex layer shown in FIG. 3. By providing such a protective layer 5, the storage stability, flame resistance, and bending durability can be improved, so the material thereof is appropriately selected depending on the purpose.

In FIG. 5, a plastic molded into a predetermined box shape 6 is used as a reinforcing agent, and a pyrrole polymer complex layer 7 is placed thereon, which can be applied as a shield box. The shape of such a box shape can be appropriately selected depending on the purpose.

The electromagnetic shielding film laminate of the present invention using a pyrrole-based polymer complex is not only strong, but also lightweight and thin, and provides a high-performance shielding effect.

The present invention will be explained in more detail below by showing production examples of pyrrole-based polymer complexes and examples in which the shielding effect was confirmed using the same.

Production Example 1 An electrolytic solution having the following composition was placed in an electrolytic cell in which a Nesa glass plate (conductive glass with vapor-deposited film of ITO, SnO and InO) was placed as an anode, and a Ni plate was placed as a cathode, facing each other. Ta.

Pyrrole (0.1 mol) paratoluenesulfonic acid (O, OS mol) Acetonitrile This solution was subjected to an anodic oxidation reaction under the following conditions to form a polymer complex film on a Nesa glass plate.

Current density 1.0 mA/c; Applied voltage 4. Ov
The properties of the produced polymer complex film are shown below.

Film thickness 50μm (20C/c+#); Doping amount 3
5% tensile strength: 10,500 psi; Electric conductivity: 90 S/cm (same for the following manufacturing examples) Film thickness: Measured by stylus film thickness meter.

Doping amount: This is the amount of aromatic anion relative to pyrrole ring 1, and is measured by elemental analysis.

Electrical conductivity: Based on the four-terminal method.

Tensile strength: Tensilon UTM-m (manufactured by Toyo Baldwin) was chucked at intervals of width IC11 and length 3 cm.

Production Example 2 An electrolytic solution having the primary composition was placed in the same electrolytic cell as used in Production Example 1.

Pyrrole (0.2 mol) para-toluenesulfonic acid Na (0.05 mol) propylene carbonate This solution was subjected to a low current electric field anodic oxidation reaction at a current density of 0.8 mA/cJ, and the polymer complex was deposited on a Nesa glass plate. produced a film of

The properties of the produced polymer complex film are shown below.

Film thickness 23 μm (6C/aI); Doping amount 38
%Tensile strength 11,0OOpsi; Electrical conductivity 3
75/cn+ Production Example 3 Into the same electrolytic cell as used in Production Example 1, an electrolytic solution having the primary composition was placed.

Pyrrole (0.2 mol) Na orthotoluenesulfonate (0.01 mol) Acetonitrile This solution was subjected to an anodic oxidation reaction under the following conditions to form a polymer complex film on a Nesa glass plate.

Current density 1.1 mA/c+#; Applied voltage 3
．． The properties of the polymer complex membrane produced at 5V are shown below.

Film thickness 45μm (14C/cnf); Doping amount
34% tensile strength 10,0OOpsi; electrical conductivity 405/an Example 1 Pyrrole polymer complex film obtained in Production Example 1 (0.34 g
/ cII), apply the acrylic resin adhesive Aron Tack [S-1213 manufactured by Toagosei Co., Ltd. to a thickness of about 4 μm,
150m x 150m+, thickness 2III! After fixing it on a positive acrylic plate, the attenuation rate (dB
) was measured to confirm the electric field shielding effect. The results are shown in the table below.

The Takeda Riken method is a general method for confirming the electric field shielding effect, and the above-mentioned acrylic plate is fixed to the Takeda Riken Spectrum Analyzer TR41.
72, and the attenuation rate is measured with an electric field rod antenna spacing of 10 nn.

Example 2 Pyrrole polymer complex film obtained in Production Example 2 (0.16g
The attenuation rate (dB) was measured in the same manner as in Example 1 except that /a&) was used. The results are shown in the table below.

Example 3 Pyrrole polymer complex film obtained in Production Example 3 (0.31 g
/al) and carbon powder (
The attenuation rate (dB) was measured in the same manner as in Example 1, except that the particles having an average particle diameter of about 2.5 μm were dispersed by about 30%. The results are shown in the table below.

Example 4 A pyrrole polymer complex film having the shape shown in FIG. 2 was obtained in the same manner as in Production Example 3, except that a Nesa glass plate with "notches" was used as an anode. Attenuation rate (dB) was measured in the same manner as in Example 1 except that this pyrrole polymer complex film (0.30 g/al) was used. The results are shown in the table below.

Example 5 In Example 2, a pyrrole polymer complex film (0°33
Attenuation rate (dB) was obtained in the same manner as in Example [, except that a protective layer was formed by blending and curing urethane [Hitaloid 3008] and curing agent [Desmodur N75] on g/d). was measured. The results are shown in the table below.

Comparative Example 1 An acrylic plate used in Example 1 coated with a copper acrylic conductive paint to a thickness of approximately 35 μ and a thickness of 0.31 g/c/) was prepared, and the attenuation rate (dB) was measured in the same manner. .

The results are shown in the table below.

Comparative Example 2 In Comparative Example 1, approximately 6% of the nickel acrylic conductive paint was used.
The attenuation rate (dB) was measured in the same manner, except that a film coated with a thickness of 1 μm (0.52 g/ant) was used.

The results are shown in the table below.

Comparative Example 3 Scotch conductive tape [manufactured by 3M, 1267] (1,02 g/
ant) on the acrylic board used in Example 1,
Attenuation rate (dB) was measured in the same manner as in Example 1. The results are shown in the table below.

As is clear from this table, the shielding effect of the pyrrole polymer complex film is excellent, and it can be understood that the laminate of the present invention formed using the film is useful as an electromagnetic shielding material.

[Brief explanation of the drawing]

1 to 4 are configuration examples of the laminate of the present invention in the form of a tape or film, and FIG. 5 is a sectional view of an example in the form of a box. 1. Release paper; 2. Adhesive layer 3.7. Pyrrole polymer complex layer 4, conductive filler; 5. Protective layer 6, plastic molded reinforcing layer Patent applicant Ricoh Co., Ltd. et al.

Claims (1)

[Claims] An electromagnetic shielding laminate having a layer of a pyrrole polymer complex containing an aromatic anion and a pyrrole monomer as main components.