JPH0660198U - Flexible sheet to prevent electrical and electromagnetic interference - Google Patents

Abstract

(57) [Abstract] [Purpose] To provide a flexible sheet which has a practically sufficient mechanical strength and prevents generation of static electricity, electrostatic charge, and interference from electromagnetic waves. [Constitution] 2 to have a specific resistance value of less than 10 ⁸ Ω · cm
3 layers of (semi) conductive flexible sheet and 10 ¹⁰ Ω
・ Insulating flexible sheet parts with a specific resistance value of cm or more are laminated alternately, and both surfaces of this laminate are (half)
Conductive, (semi) conductive flexible sheet part,
A matrix containing a rubber or a synthetic resin and a conductive substance dispersed therein, and the insulating flexible sheet portion is formed of an insulating rubber or a synthetic resin. ) A flexible sheet for preventing electrical and electromagnetic interference, in which a fiber cloth reinforcing material layer is sandwiched and laminated in at least one of the layers with the conductive flexible sheet portion.

Description

[Detailed description of the device]

[0001]

[Industrial applications]

 The present invention relates to a flexible sheet for preventing electric and electromagnetic interference, which can effectively prevent electric and electromagnetic interference, and which has practically sufficient mechanical strength.

[0002]

[Prior art]

Conventionally, flexible sheets made of various synthetic resins or synthetic or natural rubber have been used as flexible covering materials for equipment covers and the like, and many of them are reinforced with fiber materials. However, these sheets were electrically insulating in nature and generally had a resistivity value of 10 ¹⁰ to 10 ¹⁷ Ω · cm or more, often 10 ¹² Ω · cm or more. Therefore, these conventional sheets have a strong tendency to generate static electricity due to surface friction and become charged.

As various electric devices have been developed and spread in recent years, the occurrence of static electricity and electromagnetic interference due to static electricity generation and electrification of the flexible sheet has increased, and a drastic solution to this problem is strongly required. It's coming.

In the case of such a flexible sheet, it may be possible to achieve the object by applying a conductive paint or the like on the surface of an ordinary non-conductive sheet. Adhesion to the surface of the sheet becomes a problem, and the flexible sheet is easily bent due to severe bending, and it is difficult to obtain a sheet having a sufficient practical service life. In addition, when applying a conductive paint, there are many limitations on the hue, and it is difficult to obtain a colorful sheet, and there are problems such as the coating technique and the performance of the coating film. It was difficult to form a conductive film.

In addition, even if only one side of the sheet is made conductive, if the opposite side is insulative, the opposite side is easily charged with static electricity. In terms of antistatic properties, it could not be used in applications where static electrification is extremely disliked.

[0006]

[Problems to be solved by the device]

 The present invention seeks to provide a flexible sheet that does not generate static electricity and is not charged, and therefore does not generate electric and electromagnetic interference.

[0007]

[Means for Solving the Problems]

The flexible sheet for preventing electric and electromagnetic interference according to the present invention comprises two or three layers of conductive or semi-conductive flexible sheet portion having a specific resistance value of less than 10 ⁸ Ω · cm, and the two or three layers of conductive sheet. Between the flexible or semi-conductive flexible sheet portions, which are laminated together, and which have one or two layers of electrically insulating flexible sheet portions having a specific resistance value of 10 ¹⁰ Ω · cm or more. The front and back surfaces of the laminate are formed by the conductive or semi-conductive flexible sheet portion, and the conductive or semi-conductive flexible sheet portion is made of electrically insulating rubber and synthetic resin. The insulating flexible sheet portion comprises a matrix component consisting of at least one selected and a conductive substance contained in the matrix component. It is formed of at least one selected from an insulating rubber and a synthetic resin, and a fiber is provided in at least one of the layers between the electrically insulating flexible sheet portion and the electrically conductive or semi-conductive flexible sheet portion. A reinforcing material layer made of a flexible cloth is sandwiched between the reinforcing material layers.

[0008]

[Action]

The flexible sheet for preventing electrical and electromagnetic interference of the present invention (hereinafter referred to as the flexible sheet of the present invention) has one or two layers of electrically insulating flexible sheet portion, and two layers which are alternately laminated and bonded, or A laminated body having three layers of conductive or semi-conductive flexible sheet portions, and the front and back surfaces of this laminated body are each formed by one layer of the conductive or semi-conductive flexible sheet portion. The specific resistance value of the insulating flexible sheet portion used in the present invention is 10 ¹⁰ Ω · cm or more, preferably 10 ¹⁰ to 10 ¹⁸ Ω · cm.

In addition, the conductive or semi-conductive flexible sheet portion used in the present invention has a specific resistance value of less than 10 ⁸ Ω · cm, and particularly has a specific resistance value of 10 ⁵ Ω · cm or less. The flexible sheet portion is preferable, and in this case, the specific resistance value thereof may be 10 ¹ Ω · cm or less, if necessary.

In the flexible sheet of the present invention, each of the insulating sheet and the conductive or semi-conductive sheet needs to be flexible. In the flexible sheet of the present invention, both front and back surfaces are formed of conductive or semi-conductive flexible sheet portions, and one layer of insulating property is provided between the front and back conductive or semi-conductive flexible sheet portions. A sheet-like base body composed of a flexible sheet part or composed of two layers of an insulating flexible sheet part and one layer of an electrically conductive or semi-conductive flexible sheet part inserted and laminated between them is sandwiched and laminated. There is. Further, a reinforcing material layer made of fibrous cloth is laminated and sandwiched between at least one of the layers between the insulating flexible sheet portion and the conductive or semi-conductive flexible sheet portion.

The conductive or semi-conductive flexible sheet portion used in the present invention is prepared by blending a conductive material in a matrix made of synthetic resin, synthetic rubber or natural rubber, and setting the specific resistance value of this blend to a predetermined value. It is formed by adjusting.

As described above, an electrically insulating synthetic resin, synthetic rubber, or natural rubber is used for the matrix of the conductive or semi-conductive flexible sheet portion and the insulating flexible sheet portion constituting the flexible sheet of the present invention. To be done. Examples of preferable synthetic resins include polyvinyl chloride (PVC), polyurethane, ethylene-vinyl acetate copolymer, isotactic polypropylene, polyethylene, polyacrylonitrile, polyester and polyamide, and other known materials. Examples of preferable synthetic rubbers include styrene-butadiene rubber (SBR), chlorosulfonated polyethylene rubber, polyurethane rubber, butyl rubber and isoprene rubber, and other known materials. The most preferred synthetic resin is PVC, which may contain plasticizers, fillers, colorants, stabilizers, blowing agents and / or other modifiers. Further, these rubbers or synthetic resin materials may contain air bubbles or may be porous depending on the use or purpose.

The conductive material mixed in the matrix of the conductive or semi-conductive flexible sheet portion to control its specific resistance value to a desired value includes liquid, powder, fibrous and foil. -Shaped, linear or sheet-shaped conductive substances such as carbon black, metals such as Al, Au, Ag, Pt, Cu, Cr, Ni, Zn, Ti, Pb, Sn, Pd and their compounds or Ni -Cr alloys, or other conductive compounds such as indium oxide. The amount of the conductive substance blended is determined in consideration of the inherent conductivity, properties and desired degree of conductivity of the substance, but it is preferably at least 5% by weight, and 10 to 70% by weight. It is more preferable that there is. Of course, the compounding amount of the conductive material is not limited to 70% by weight or less, and particularly in the case of the conductive flexible sheet portion, desired flexible sheet properties (strength, flexibility, appearance, etc.) can be obtained. As long as it has, it may be more than 70% by weight. For reference, the specific resistance values of various materials are shown below.

Material resistivity (Ω · cm) Natural asphalt 10 ¹⁵ to 10 ¹⁷ Vulcanized natural rubber 10 ¹⁵ to 10 ¹⁷ Butyl rubber 10 ¹⁵ to 10 ¹⁶ SBR 10 ¹² Polyisoprene 10 ¹⁵ Ethylene-propylene rubber 10 ¹⁵ to 10 ¹⁶ Neoprene 10 ¹⁰ to 10 ¹² Chlorosulfonated polyethylene rubber 10 ¹⁴ Urethane rubber 10 ¹⁴ to 10 ¹⁵ Polyethylene terephthalate 10 ¹⁹ Nylon 6 10 ¹² to 10 ¹⁵ Nylon 66 10 ¹³ to 10 ¹⁴ Polypropylene 10 ¹⁶ Polyvinyl chloride 10 ¹⁶ to 10 ¹⁷ Nomec paper 10 ¹⁶ cotton 10 ^{7 -10 12} carbon black, graphite 100 ^{0 -10 -3} stainless steel 10 ^{-4 -10 -6}

The thickness of each of the insulating flexible sheet portion and the conductive or semi-conductive flexible sheet portion is not particularly limited as long as the flexibility of the sheet is not impaired, but it is generally preferably 1 μm or more, The thickness is more preferably 10 to 1000 μm, but of course it may be thicker than this.

As described above, the flexible sheet of the present invention made of the above-mentioned materials is a combination of the conductive or semi-conductive flexible sheet portion, the insulating flexible sheet portion, and the fiber cloth reinforcing material layer. However, the structure of the flexible sheet of the present invention will be described below in more detail with reference to the accompanying drawings.

1 and 2 are cross-sectional views schematically showing an example of an electric and electromagnetic wave interference preventing flexible sheet according to the present invention in the accompanying drawings. In the flexible sheet of the present invention shown in FIG. 1, conductive or semi-conductive flexible sheet portions 2a and 2b are formed on both sides of a sheet-like base body made of an insulating flexible sheet portion 1a. A fiber cloth reinforcing material layer 3a is laminated and sandwiched between 1a and a conductive or semi-conductive flexible sheet portion 2a. This reinforcing material layer may be disposed between the insulating flexible sheet portion 1a and the conductive or semi-conductive flexible sheet portion 2b.

In the flexible sheet shown in FIG. 2, the sheet-like substrate 4 has two layers of insulating flexible sheet portions 1b and 1c, and one layer of conductive or semi-conductive material inserted and laminated between them. The flexible sheet 2c and the conductive or semiconductive flexible sheet portions 2a and 2b are arranged on both front and back surfaces thereof, and the conductive or semiconductive flexible sheet portion 2a and the insulating flexible sheet portion 1b are provided. The fiber fabric reinforcing material layer 3b is laminated and sandwiched between them, and the fiber fabric reinforcing material layer 3c is laminated and sandwiched between the insulating flexible sheet portion 1c and the conductive or semi-conductive flexible sheet portion 2b. The fiber cloth reinforcing material layer may be laminated and sandwiched between one or both of the layers of the conductive or semi-conductive flexible sheet portion 2c of the sheet substrate 4 and the insulating flexible sheet portions 1b and 1c. . The flexible sheet of the present invention having the configuration shown in FIG. 2 is a particularly preferred embodiment because it can improve the safety and reliability even when the usage environment conditions on the front and back sides are different.

In the production of the flexible sheet of the present invention, the conductive or semiconductive flexible sheet portion may be formed of a conductive or semiconductive sheet (or film), or may be conductive or semiconductive. It may be formed from a film forming liquid.

In order to carry out the above steps, a calendar method, a topping method, a dipping method, a coating method, a laminating method, an extrusion molding method, a spreading method and any other method can be used.

In the flexible sheet of the present invention, as shown in FIG. 1, two outer surfaces are formed by conductive or semi-conductive flexible sheet portions 2a and 2b, and a sheet-like substrate inside thereof is made into an insulating flexible sheet portion 1a. Alternatively, the fibrous fabric reinforcing material layer 3a may be disposed on one or two of these layers. In this case, the seat has a structure that conforms to the required performance when using the upper and lower surfaces, and does not cause problems such as clinging when handling.

As shown in FIG. 2, two layers of insulating flexible sheet portions 1b and 1c are sandwiched between them, and one layer of conductive or semi-conductive flexible sheet portion 2c is provided. A flexible sheet of the present invention comprising a sheet-like substrate 4 composed of the above, and a conductive or semi-conductive flexible sheet portion covering both front and back sides with fibrous fabric reinforcing material layers 3b and 3c. In this case, the conductive flexible sheet portions 2a and 2b on the outermost surfaces on both the front and back sides have antistatic and electromagnetic wave blocking functions, respectively, and the insulating flexible sheet portions 1b and 1c thereunder prevent leakage, and The lower conductive flexible sheet portion 2c (center layer) blocks electromagnetic waves to prevent the interference, and the insulating flexible sheet portion 1c below the flexible flexible sheet portion 2c is the flexible sheet of the present invention. Improve the electrical insulation of the grate. Therefore, the electrical conditions applied (or generated) to one of the conductive or semi-conductive flexible sheet portions on the outermost surfaces of the front and back do not work with the other, and they are independent of static charge prevention, and The effect of preventing electromagnetic interference can be improved. Therefore, the flexible sheet of the present invention having this structure may be used by making the electric conditions on the front and back sides different from each other. For example, even if the flexible sheet of the present invention is used as a work sheet, it is possible to prevent electrical changes or troubles on the outer surface from affecting electric equipment or the human body in contact with the inner surface.

The flexible sheet of the present invention includes a reinforcement layer. This reinforcing material layer is formed of a fibrous fabric. The fibrous fabric useful in the present invention includes natural fibers such as cotton and hemp, inorganic fibers such as glass fibers, regenerated fibers such as viscose rayon and cupra, and semi-synthetic fibers such as di- And triacetate fibers, and synthetic fibers such as nylon 6, nylon 66, polyester (polyethylene terephthalate) fibers, aromatic polyamide fibers, acrylic fibers, polyvinyl chloride fibers, and polyolefin fibers. At least one type can be used. The fibers in the cloth may be any shape such as short fiber spun yarn, long fiber yarn, split yarn, tape yarn, etc., and the fabric may be woven fabric, knitted fabric, non-woven fabric, paper-like fabric or composite fabric thereof. It may be either. Generally, the fibers used in the flexible sheet of the present invention are preferably polyester fibers, and the fibers are preferably in the form of long fibers (filaments). The fibrous cloth is useful for maintaining the mechanical strength of the obtained flexible sheet of the present invention at a high level. Examples of useful woven fabrics include twill woven fabrics, plain woven fabrics and other woven fabrics having a general design.

In the present invention, the fibrous fabric reinforcing material layer is sandwiched and laminated between at least one layer between the conductive or semi-conductive flexible sheet portion and the insulating flexible sheet portion. Of course, such a fibrous fabric reinforcing material layer may be contained not only in one layer but also in two layers or more.

The conductive or semi-conductive flexible sheet portion has the effect of preventing electrostatic charging and shielding of penetrating electromagnetic waves. This effect is obtained by the insulating flexible sheet portion and the conductive or semi-conductive flexible sheet portion. It can be obtained even if the fibrous fabric reinforcing material layers are not directly adjacent to each other but are interposed between the layers.

Hereinafter, the present invention will be further described with reference to examples.

【Example】

As an example of the flexible sheet of the present invention, a plain woven fabric was prepared by weaving 250 denier polyester filaments for warp and weft at a density of 45 filaments / 25.4 mm. An insulating sheet containing 100 parts by weight of polyvinyl chloride resin, 60 parts by weight of dioctyl phthalate, and a predetermined amount of stabilizer was adhered to one side of the plain woven fabric. The plain weave fabric / insulating flexible sheet adhesive was a flexible sheet having a thickness of about 0.25 mm. The specific resistance value of the insulating flexible sheet was 10 ¹⁶ Ω · cm.

Next, a conductive processing liquid containing 100 parts by weight of polyvinyl chloride resin and 250 parts by weight of carbon black was applied to both surfaces of the plain weave fabric / insulating sheet adhesive, dried, and dried at 180 ° C. Was subjected to gelation heat treatment to form a conductive flexible sheet portion having a thickness of 0.1 mm on each side and a specific resistance of 10 ⁴ to 10 ⁶ Ω · cm. The total thickness of the obtained flexible sheet was about 0.5 mm.

When a simple box was made in the laboratory using the flexible sheet of the present invention, and sewing work was performed using a high-frequency sewing machine in the box, no noise was generated on the television screen that was lit just outside. It was For comparison, a similar test was conducted using a conventional PVC sheet, but the television screen was disturbed. Similarly, in the test conducted with the conventional PVC sheet which is only subjected to the antistatic treatment, the TV screen is disturbed.

In addition, the flexible sheet of the present invention does not generate static electricity and is not charged on either of the front and back surfaces thereof, and has relatively high conductivity on both surfaces. For example, it was possible to block problems such as discharge and leakage, and the flexible sheet as a whole could be put to practical use safely and effectively without problems such as charging, discharge, and leakage.

[0030]

[Effect of device]

 The flexible sheet of the present invention prevents electrostatic charging on both front and back sides, does not cause electromagnetic interference, has no danger of leakage to the back side, and has the above-mentioned electrical characteristics even when used for applications with severe surface friction. It has an extremely epoch-making composite effect that can hold the material with good durability. Therefore, the flexible sheet of the present invention has a surprising advantage that it can be used for various purposes by itself, and has great industrial value. Further, since the flexible sheet of the present invention is flexible, it can be coated on any article in its original shape, and can be sewn into any shape to be used. This makes it possible to easily supply an extremely wide variety of products. Further, the flexible sheet of the present invention has practically sufficient mechanical strength.

[Brief description of drawings]

FIG. 1 is an explanatory cross-sectional view of an example of a flexible sheet of the present invention.

FIG. 2 is a cross-sectional explanatory view of another example of the flexible sheet of the present invention.

[Explanation of symbols]

1a, 1b, 1c ... Electrically insulating flexible sheet portion 2a, 2b, 2c ... Conductive or semi-conductive flexible sheet portion 3a, 3b, 3c ... Fibrous fabric reinforcing material layer 4 ... Sheet-shaped substrate

Claims (8)

[Scope of utility model registration request] 1. A two-layer or three-layer conductive or semi-conductive flexible sheet portion having a specific resistance value of less than 10 ⁸ Ω · cm, and the two-layer or three-layer conductive or semi-conductive flexible sheet. It is inserted and laminated between layers of parts, and 1
A laminate having one or two layers of electrically insulating flexible sheet having a specific resistance value of 0 ¹⁰ Ω · cm or more, wherein the front and back surfaces of the laminate each have one layer of the conductive material. Alternatively, the conductive or semi-conductive flexible sheet portion is formed by a semi-conductive flexible sheet portion, and the conductive or semi-conductive flexible sheet portion comprises a matrix component consisting of at least one selected from an electrically insulating rubber and a synthetic resin, and a matrix component in the matrix component. And a conductive material contained therein, wherein the conductive or semi-conductive flexible sheet portion is formed of at least one selected from an electrically insulating rubber and a synthetic resin, and the electrical insulation Reinforcing material layer made of fibrous cloth in at least one of the layers between the flexible sheet portion and the conductive or semi-conductive flexible sheet portion. Is sandwiched, electrical and electromagnetic interference preventing flexible sheet characterized by. 2. The flexible sheet for preventing electric and electromagnetic interference according to claim 1, wherein the conductive flexible sheet portion has a specific resistance value of 10 ⁵ Ω · cm or less. 3. The flexible sheet for preventing electric and electromagnetic interference according to claim 1, wherein the insulating flexible sheet portion has a specific resistance value of 10 ¹⁰ to 10 ¹⁸ Ω · cm. 4. The electrical and electromagnetic interference prevention flexible according to claim 1, wherein the insulating rubber is selected from natural rubber, styrene-butadiene rubber (SBR), chlorosulfonated polyethylene rubber, polyurethane rubber, butyl rubber, and isoprene rubber. Sheet. 5. The insulating synthetic resin is polyvinyl chloride,
The flexible sheet for preventing electric and electromagnetic interference according to claim 1, which is selected from polyurethane, ethylene-vinyl acetate copolymer, polypropylene, polyethylene, polyacrylonitrile, polyester, and polyamide. 6. The flexible sheet for preventing electrical and electromagnetic interference according to claim 1, wherein the content of the conductive material is at least 5% by weight based on the conductive or semiconductive flexible sheet portion. 7. The flexible sheet for preventing electric and electromagnetic interference according to claim 6, wherein the content of the conductive material is 10 to 70% by weight. 8. The conductive material is carbon black,
The flexible sheet for preventing electric and electromagnetic interference according to claim 1, which is selected from a conductive metal, a conductive alloy and a conductive metal compound.