JP2003170518A - Conductive sheet and method for manufacturing the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a conductive sheet excellent in production efficiency, more inexpensive and having a conductive coating layer having stable quality. <P>SOLUTION: After the conductive coating layer is provided on the single surface of a thermoplastic resin film to obtain a conductive film, a thermoplastic resin sheet is extruded and the surface opposite to the conductive coating layer of the conductive film is used as a laminating surface to be thermally laminated to the thermoplastic resin sheet by the heat of the extruded thermoplastic resin sheet to obtain the conductive sheet. As the thermoplastic resin sheet, a polystyrenic resin sheet is preferable and, as the thermoplastic resin film, a polystyrenic resin film and a polypropylene resin film are preferable. <P>COPYRIGHT: (C)2003,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a conductive sheet used for molding various containers, trays, carrier tapes, etc., whose surface is required to have conductivity, and a method for manufacturing the same.

[0002]

2. Description of the Related Art Conventionally, electronic parts used in various electronic devices are easily broken by static electricity, so that they are packaged with conductive packaging materials such as containers, trays and carrier tapes for storage and storage. Transportation is done.
Such a packaging material is usually used after being molded into a desired shape by various molding methods using a conductive sheet having a conductive coating layer provided on the surface of a base material sheet. Such a conductive sheet is a conductive coat layer formed by applying and drying a conductive paint comprising conductive particles, a binder and a solvent for dissolving and dispersing these on one or both sides of a base material sheet usually made of a thermoplastic resin. Are manufactured by forming.

[0003]

In the case of a relatively thick sheet used for molding a tray or the like, the conductive coat layer of the above-mentioned conventional conductive sheet is one of the base sheet cut to a predetermined size. Since it is formed by applying and drying conductive paint on each sheet, the production efficiency is very poor,
The conductive sheet obtained is expensive. Further, in the case of a relatively thin sheet used for forming a carrier tape or the like, since the base material sheet can be wound in a roll shape,
A conductive coating can be continuously applied and dried by a roll coater method, a spray coater method, etc., but it is difficult to obtain a uniform conductive coat layer due to uneven thickness of the base sheet or surface roughening, and the conductive coat The quality of the layer (eg surface resistivity) becomes unstable.

Therefore, an object of the present invention is to provide a conductive sheet which is inexpensive and has a stable conductive coat layer quality. Further, the present invention is a method for producing a conductive sheet in which a conductive coat layer can be continuously formed on both a relatively thick base sheet and a relatively thin base sheet, and the quality of the conductive coat layer is stable. Is to provide.

[0005]

Means for Solving the Problems The present inventors have extruded a thermoplastic resin sheet, while the other surface of the thermoplastic resin film provided with a conductive coating layer on one surface, one surface of the thermoplastic resin sheet or The present invention has been completed by finding that the above object can be achieved by laminating both surfaces by thermal lamination.

That is, the present invention comprises the following aspects (1) to (5). (1) A conductive sheet in which a thermoplastic resin film and a conductive coating layer are sequentially laminated on one side or both sides of the thermoplastic resin sheet.

(2) The thermoplastic resin sheet is a polystyrene (hereinafter referred to as "PS") type resin sheet, and the thermoplastic resin film is a PS type resin film. Conductive sheet.

(3) The thermoplastic resin sheet is a PS-based resin sheet, and the thermoplastic resin film is a polypropylene (hereinafter referred to as "PP")-based resin film. Conductive sheet.

(4) The thermoplastic resin sheet is a PS-based resin sheet, and an adhesive layer capable of being heat-bonded to the PS-based resin sheet is provided on the surface of the thermoplastic resin film facing the PS-based resin sheet. The conductive sheet according to (1) or (3) above, which is a PP resin film.

(5) While extruding the thermoplastic resin sheet,
The surface opposite to the conductive coat layer of the thermoplastic resin film laminated with the conductive coat layer is thermally laminated on one side or both sides of the thermoplastic resin sheet (1) to (4). A method for manufacturing a conductive sheet.

[0011]

BEST MODE FOR CARRYING OUT THE INVENTION The conductive sheet according to the present invention comprises a thermoplastic resin sheet, a thermoplastic resin film and a conductive coat layer.

The thermoplastic resin sheet used in the present invention is a sheet which is a base material of the conductive sheet and has a thickness of about 0.2 to 3 mm. As the type of the thermoplastic resin, a resin that can be thermoformed is basically used since the conductive sheet of the present invention is subjected to thermoforming such as vacuum or pressure forming and press forming. Specifically, for example, PS resin, polypropylene, polyester, acrylic resin or the like can be used. Among these, PS resins are particularly preferable because they have excellent thermoformability and easily obtain the strength required for molded articles for packaging electronic parts.

The PS resin is GPPS (general-purpose polystyrene) resin, HIPS (shock-resistant polystyrene).
A resin containing styrene as a main component, such as a resin, may be used, but these PS resins may be used alone,
You may mix and use it. Further, a rubber substance such as a styrene-butadiene block copolymer or a hydrogenated product thereof may be added to these. Furthermore, if necessary, known resins and rubbers and various additives (lubricants, antioxidants, inorganic fillers, etc.) may be added as long as the performance is not impaired. Alternatively, PS-based resin recovered from scrap may be used.

The thickness of the thermoplastic resin film used in the present invention is about 5 to 100 μm. As the type of the thermoplastic resin, basically, a resin that can be thermally laminated with the thermoplastic resin sheet can be used, and is appropriately selected according to the type of the resin of the thermoplastic resin sheet.
Specifically, PS-based resin, PP-based resin, polyester,
Examples thereof include polyamide, and PS-based resins and PP-based resins having good thermoformability are particularly preferable. Examples of the PS resin film include an OPS (biaxially oriented polystyrene) film and a HIPS (impact-resistant polystyrene) film. Examples of the PP resin film include an OPP (biaxially stretched polypropylene) film and a CPP (unstretched polypropylene) film, and the CPP film is preferable from the viewpoint of thermoformability.

Preferred combinations of the thermoplastic resin sheet and the thermoplastic resin film from the viewpoint of thermoformability are a combination of a PS resin sheet and a PS resin film, and a combination of a PS resin sheet and a PP resin film. There is. In the latter case, a combination of PS resin sheet and CPP film is more preferable. PS resin sheet and PS
In the case of the combination with the system resin film, there is no problem in adhesion by thermal lamination, but in the case of the combination of the PS type resin sheet and the PP type resin film, the adhesive force may be insufficient in the thermal lamination. In this case, an adhesive layer can be provided on the adhesive surface side of the PP resin film.

The above adhesive layer is applied to the PP resin film by OP.
Laminate S film, HIPS film, etc.,
Alternatively, it is formed by coating the surface of the PP resin film with hot melt, a heat sealing agent or the like having good heat adhesion to the PS resin.

The conductive coating layer is a layer obtained by applying and drying a conductive coating material. The conductive coating material is a solution in which conductive particles and a resin binder are dissolved or dispersed in water or an organic solvent or a mixture thereof. is there. As the conductive particles, any conventionally known conductive particles can be used, but usually conductive carbon black, conductive oxide such as tin oxide and zinc antimonate, conductive polymer particles such as polypyrrole and polyaniline, and various metals. Particles or the like are used. The resin binder is not particularly limited, and can be selected depending on the adhesiveness to the film, the physical properties of the conductive particles, and the like. For example, an acrylic ester copolymer, a styrene-acrylic copolymer, a urethane polymer. Etc.
Further, additives (inorganic filler, polyethylene wax, etc.) for preventing blocking may be added to the conductive paint.

The conductive coat layer has a two-layer structure in which a protective layer formed by coating and drying the above-mentioned resin binder coating is provided on a layer obtained by coating and drying the above-mentioned coating containing only the conductive particles. May be.

The conductive coat layer is formed on the thermoplastic resin film by applying the conductive paint on one side of the film and drying it. In order to improve the adhesion of the conductive coat layer to the film, the film may be subjected to surface treatment such as corona discharge treatment, plasma treatment, flame treatment and the like. As a coating method, generally used methods such as commonly used roll coating, air knife coating, blade coating, and bar coating can be used. After coating, the solvent is dried and removed using an oven, a drier, etc. A layer is formed. Two
In the case of a layer structure, the conductive coating layer is formed by successively repeating these coating methods twice. The thickness of the conductive coat layer is usually about 0.1 to 10 μm.

While the thermoplastic resin sheet is being extruded, the heat of the extruded sheet causes the thermoplastic resin film provided with the conductive coating layer to be bonded to the thermoplastic resin sheet with the surface opposite to the conductive coating layer as the bonding surface. The conductive sheet of the present invention can be obtained by heat lamination. According to the method for producing a conductive sheet of the present invention, the conductive coat layer can be continuously provided on the thermoplastic resin sheet, so that the conductive sheet can be efficiently produced. Further, according to the method for producing a conductive sheet of the present invention, a uniform conductive coat layer can be obtained, so that a conductive sheet having stable quality of the conductive coat layer can be obtained.

[0021]

EXAMPLES The present invention will now be described based on examples, but the present invention is not limited to the specific modes of the following examples.

[0022]

Example 1 An OPS film having a thickness of 25 μm was subjected to corona discharge treatment, and the corona discharge treated surface was mixed with conductive particles of antimony oxide-doped stannic oxide and a binder resin composed of a polyester resin and an acrylic resin. The coating material was applied and dried to obtain a conductive film having a conductive coating layer having a thickness of 3 μm. Next, this conductive film was thermally laminated with a pressure bonding roll while extruding a 2 mm-thick HIPS sheet so that the surface opposite to the conductive coat layer was in contact with the surface of the HIPS sheet to obtain a conductive sheet. The surface resistivity of the conductive coat layer surface of this sheet is 2.3.
It was about 2.7 × 10 ⁶ Ω / □ and was stable.

Example 2 A conductive film was obtained by coating conductive carbon black on one side of a CPP film having a thickness of 30 μm and drying it, and then coating a binder resin mainly composed of polyester resin and drying it. Then, a heat-sealant containing ethylene-vinyl acetate copolymer as a main component was applied to the surface opposite to the conductive coat layer and dried to provide an adhesive layer on the conductive film having a conductive coat layer having a thickness of 1 μm. This conductive film was thermally laminated with a pressure bonding roll while extruding a 2 mm-thick HIPS sheet so that the surface of the adhesive layer was in contact with the surface of the HIPS sheet, to obtain a conductive sheet. The surface resistivity of the conductive coat layer surface of this sheet is 2.8 to 4.1 × 10.
^{It was 4} Ω / □ and was stable.

[0024]

As described above, according to the present invention,
By providing the conductive coating layer continuously on the thermoplastic resin sheet, the conductive sheet can be efficiently manufactured, and the conductive sheet having stable quality of the conductive coating layer can be obtained.

   ─────────────────────────────────────────────────── ─── Continued front page    F term (reference) 4F100 AK01B AK01C AK01D AK07C                       AK12B AK12C AK12D AR00A                       AR00E BA05 BA06 BA10A                       BA10E EC182 EJ172 EJ422                       EK06 GB15 GB16 GB41 JB16B                       JB16C JB16D JG01 JG01A                       JG01E

Claims (5)

[Claims] 1. A thermoplastic resin sheet on one side or both sides,
A conductive sheet comprising a thermoplastic resin film and a conductive coat layer sequentially laminated. 2. The conductive sheet according to claim 1, wherein the thermoplastic resin sheet is a polystyrene resin sheet, and the thermoplastic resin film is a polystyrene resin film. 3. The conductive sheet according to claim 1, wherein the thermoplastic resin sheet is a polystyrene resin sheet, and the thermoplastic resin film is a polypropylene resin film. 4. The thermoplastic resin sheet is a polystyrene-based resin sheet, and the thermoplastic resin film is provided with an adhesive layer capable of being heat-bonded to the polystyrene-based resin sheet on the surface of the thermoplastic resin film facing the polystyrene-based resin sheet. The conductive sheet according to claim 1 or 3, which is a polypropylene resin film. 5. A thermoplastic resin sheet is extruded while the surface of the thermoplastic resin film laminated with a conductive coating layer opposite to the conductive coating layer is thermally laminated on one side or both sides of the thermoplastic resin sheet. Claims 1 to 4 characterized
A method for producing a conductive sheet according to any one of 1.