JPH0345159B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention relates to a method for manufacturing a conductive laminated sheet suitable for use in electronic components, and more specifically to a transparent conductive laminated sheet used for packaging electronic components, storage of electronic components, and mounting of electronic components on a mounting board. The present invention relates to a method for manufacturing a conductive laminated sheet that does not require transparency and can be used as a conveying tape for conveying objects. Electronic components such as semiconductor ICs and LSIs, printed circuit boards,
Magnetic tapes, etc. need to protect products from problems caused by static electricity that attracts dust and electrostatic charges during the packaging, shipping, and transportation processes.In particular, C-MOS type ICs, which are commonly used these days, can suffer dielectric breakdown due to static electricity. Therefore, prevention of static electricity has become essential. In order to protect products from these static electricity hazards, it is conceivable to package and store them in bags or containers made of conductive film with low surface resistivity. In addition, for transactions such as the above-mentioned ICs, it is desirable that the packaged contents can be seen through and judged, so when packaging with conductive film, the conductive film itself must have some degree of transparency. It is also required to have the strength to withstand paper manufacturing, container molding processing, use, etc. Furthermore, conductive materials used as tapes for storing and transporting electronic components generally do not require transparency, but are required to have high mechanical strength and moldability. Conventionally, a method for producing conductive polyolefin materials has been proposed in which paper stock is made by mixing carbon fibers into polyolefin-based synthetic pulp, and the resulting paper-like material is thermally fused at a temperature higher than the melting point of the polyolefin component. Publication No. 52-13214). However, when manufacturing a conductive film made only of polyolefin synthetic pulp and carbon fiber, the paper-like material is melted as is, so the tensile strength is lost, and it is actually difficult to continuously manufacture the film while winding it up. In particular, it has been impossible to produce a film with low basis weight and excellent transparency. In addition, if strong pressure is applied during heat fusion, the carbon fibers will break and the in-plane specific resistance of the film (Ω・
cm) is made non-uniform, so only weak pressure can be applied, and as a result, a highly transparent film cannot be obtained. Furthermore, the work of laminating conductive films with high-strength sheets to give them mechanical strength was done in a separate process, such as dry lamination using adhesives or extrusion coating, which reduced costs. It was becoming expensive. In view of the above problems, the present inventor developed a continuous conductive laminated sheet that is strong enough to withstand manufacturing, processing, and use, and has a stable specific resistance (Ω cm) of the conductive layer, and that is mainly highly transparent. The present invention was achieved as a result of repeated research to provide a method for manufacturing the same. The minimum unit of the conductive laminated sheet obtained in the present invention is a two-layer laminated sheet consisting of a transparent conductive film layer and a high-strength sheet layer with relatively high surface resistance. A laminated sheet consisting of a transparent conductive film layer and a transparent film layer (high strength sheet layer) with an opacity of 30%.
The following laminated sheets can be mainly used for packaging bags. In addition, transparent conductive film layer and paper,
A laminated sheet consisting of an opaque sheet layer (high-strength sheet layer) made of nonwoven fabric, metal foil, plastic, etc. can be used for conveyance tapes, trays, and the like. The present invention comprises a step of preheating a paper-like material obtained by mixing synthetic pulp made of a thermoplastic resin and conductive fibers on a carrier, and then overlapping the plasticized paper-like material with a high-strength sheet. A thin transparent conductive film layer with a small basis weight is obtained only by combining the process of heating and pressing the paper material with the carrier between the nips of a super calender or the like to turn the paper into a transparent film, and at the same time fusing and press-bonding it to a high-strength sheet. This enables continuous production of conductive laminated sheets. According to the present invention, at least one layer of transparent conductive film is formed by dispersing conductive fibers with a fiber length of 1 to 40 mm in a thermoplastic resin matrix and exhibits an opacity of 30% or less and a specific resistance of 1×10 ⁸ Ω·cm or less. A method for producing a laminated sheet consisting of one high-strength sheet layer and one high-strength sheet layer, in which a paper-like material made by mixing synthetic pulp made of thermoplastic resin and conductive fiber is plasticized by preheating on a carrier. Then, the paper-like material is laminated with a high-strength sheet using a carrier selected from films, paper, and sheet-like materials that have good releasability, smoothness, repeated use, and heat resistance, and the synthetic pulp is layered between rolls. A conductive laminated sheet, characterized in that the laminated sheet is formed by continuously heating and pressing at a temperature above the melting point and lower than the melting point of the conductive fibers to fuse and press, cool, and then separate the carrier. A manufacturing method is provided. The synthetic pulp made of a thermoplastic resin (hereinafter referred to as synthetic pulp) used in the present invention refers to a fibrous material that can be made into paper, such as pulp made of a thermoplastic synthetic resin, short fibers, and composite fibers. In addition, examples of thermoplastic resins include polyolefin, polyacrylonitrile, polyester, polyamide, etc., but any resin that becomes transparent when melted by heating and retains its transparency even when it returns to a solid polymer by cooling. Bye. Among these, particularly preferred are polyolefins that have a low melting point and are relatively inexpensive. Polyolefin refers to polyethylene, polypropylene, a copolymer of ethylene and propylene, a copolymer of ethylene or propylene and α-olefin, a copolymer of ethylene or propylene with vinyl acetate, acrylic acid, etc., or a mixture thereof. These include polymers obtained by further chemical treatment. These polymers can also be used in combination with polyvinyl alcohol binders used in the paper industry.
In addition, in consideration of the fusion pressure bondability of the conductive film layer, those having a melting point of 200° C. or lower, particularly 170° C. or lower are preferable. In addition, papermaking pulps such as softwood bleached sulfate pulp (NBKP) and sulfite pulp can be blended to improve papermaking properties, but these blends reduce the transparency of the conductive film layer and may cause peeling of the laminated sheet. Because it weakens the strength,
Keep it below 30% by weight. As the conductive fiber, any of carbon fiber, metal fiber, organic conductive fiber, conductively processed organic fiber, etc. can be used. As the carbon fiber, commercially available ones such as ordinary carbon fiber, graphite fiber or graphite fiber can be used. Carbon fibers have a fiber length of 1 to 40 mm and a thread diameter of 5 to 40 mm.
Chopped fibers having a diameter of 30 μm can be used, but those having a diameter of 3 to 25 mm are particularly preferred. Fibers with a fiber length of 1 mm or less fall off during papermaking, causing a difference in content in the thickness direction of the resulting conductive film layer, which is unfavorable for making the resistivity uniform. Also, if it is 40 mm or more, it tends to cause flocs and has poor paper-making properties. Threads with a diameter of 30 μm or more are difficult to disperse during paper manufacturing and tend to be incompletely covered with thermoplastic resin in the conductive film layer. The most preferred range is 5-20 μm. The amount of carbon fiber used ranges from 0.5 to 30% by volume depending on its thickness. If it is less than 0.5% by volume, there is a risk of problems in conductivity, and if it exceeds 30% by volume, there is a possibility that transparency and fusion pressability will be impaired. The preferred range of usage is 1 to 10% by volume. Metal fibers include steel fibers, stainless steel fibers, aluminum fibers, cinch fibers, copper fibers, bronze fibers, etc., but stainless steel fibers, aluminum fibers, cinch fibers, etc. whose surfaces are not easily oxidized and are easy to handle are suitable. It is. In addition, copper and carbon fiber and glass fiber
Examples include those coated with metals such as aluminum and nickel. The form of metal fiber is
Fiber length 1-40mm, preferably 3-25mm, diameter 1-40mm
It is 30 μm, preferably 1 to 20 μm. The reason for limiting the fiber form is the same as that for carbon fiber. Further, the amount used is in the range of 0.5 to 30% by volume depending on the thickness, and the preferable range is 3 to 10% by volume. Organic conductive fibers are those whose fibers are essentially electrically conductive, such as polyacetylene and polyparaphenylene. Conductive processed organic fibers (hereinafter referred to as ``organic conductive processed fibers'') are various synthetic fibers, semi-synthetic fibers, or natural fibers that have been subjected to conductive processing, preferably without impairing the properties of these fibers. For example, a metal ion or a metal compound is chemically bonded to an organic fiber, or a conductive agent such as a metal or carbon is physically bonded to an organic fiber. Preferred typical examples of materials to which metal ions or metal compounds are bonded are conductive fibers in which copper ions are diffused into acrylic fibers during the dyeing process (product name: Thunderon SS-N, manufactured by Nippon Kage Seiyo Co., Ltd.);
These include conductive fibers in which cuprous iodide is adsorbed and contained in various organic fibers (Japanese Unexamined Patent Publication No. 57-39299). Also,
Examples of materials to which a conductive agent is physically bonded include organic fibers in which a conductive agent is kneaded into a base material (Japanese Patent Application Laid-Open No.
134298), carbon composite fibers, and metal-plated organic fibers (Utility Model Publication No. 49-3921), etc., but they do not impair the properties of the base organic fibers, and the conductive agent is separated during the papermaking process. Chemical bonding is more preferable because there is no risk of such bonding.
The method of electrically conductive processing is not limited to the above example, and may be carried out so that the specific resistance of the fibers is about 1×10 ⁴ Ω·cm or less, preferably about 1×10 ⁰ Ω·cm or less. The amount of these conductive fibers used is 0.5 to 30% by volume depending on their thickness, and the preferred range is 2 to 10% by volume. The form of organic conductive fibers and organic conductive processed fibers is usually 3 to 50 μm in diameter and 1 to 40 mm in length.
25 mm is particularly preferred. The reason for the limitation is the same as in the case of carbon fibers and metal fibers. In the present invention, first, a paper stock containing a mixture of synthetic pulp and the conductive fibers is made into a paper having a basis weight of 25 g/
Paper-like material with a weight of m ² to 10 g/m ² . When this is used to form a transparent conductive film layer as a component of the conductive laminate sheet of the present invention, the thickness of the film layer is 25 μm to 110 μm. 30g/m ² to 70g/m ² in terms of paper-making properties, uniformity of specific resistance, and transparency.
(The conductive film layer thickness is preferably 30 μm to 80 μm). As the high-strength sheet, film, paper, nonwoven fabric, metal foil, etc. are selected and used depending on the purpose. Examples of films include vinyl chloride, polyethylene, polypropylene, and nylon, but generally any film that can be thermally laminated can be used. Among these, films whose melting points are close to that of the synthetic pulp used for paper-like materials are fused and laminated together by the method of the present invention. For example, when the synthetic pulp is polyethylene-based and the film is high-density, medium-density, low-density polyethylene, etc. In addition, in the case of a film having a higher heat distortion temperature than synthetic pulp, for example, when using acrylic, polyester, polyvinyl alcohol, polyamide, cellophane, glassine paper, etc. in place of the polyethylene synthetic pulp, The crimping surface of the film on which the paper-like material is fused and crimped is previously subjected to a corona discharge treatment using a known technique.
The object of the present invention is achieved by performing flame treatment, spark discharge treatment, etc., anchor coating with an adhesion promoter, and using a composite film of ionomer resin, polyethylene, EVA, etc. be able to. In short, any film that can simultaneously make the paper-like material transparent by heating and pressing and fusion bonding is sufficient; if transparency is required, select a film with a thickness in the range of 10 to 100 μm. The opacity of the laminated sheet should be 30% or less. Note that when a single conductive fiber, especially a paper-like material containing carbon fiber or metal fiber, is thermally fused to form a film, the thermoplastic resin that is the matrix has a large thermal expansion change with respect to the conductive fiber. This not only causes wrinkles in the film appearance and lowers its commercial value, but also reduces the contact efficiency between the conductive fibers and makes the specific resistance in the plane direction non-uniform.
These drawbacks arise when the conductive film is formed thickly,
Further, this can be prevented by using conductive fibers in an amount of 30% or more by volume. However, in the present invention, from the viewpoint of transparency of the conductive film layer and peel strength of the laminated sheet, the amount of conductive fiber used is limited to 30% by volume or less, preferably 10% by volume or less. The thickness of the conductive film layer is as follows.
The objective of the present invention is to be achieved by setting the thickness to 110 μm or less, preferably 80 μm or less. That is, in the present invention, as described later, the pressure bonding with the high-strength sheet is carried out using a carrier under appropriate heating and pressure conditions, and the formation of the paper-like material into a transparent film and the fusion pressure bonding are simultaneously carried out to form a transparent film layer. It is believed that the above-mentioned drawbacks do not appear because the material is cooled while being firmly attached to the high-strength sheet layer and also in close contact with the smooth carrier surface. The above-mentioned effect appears similarly when non-transparent film, paper, non-woven fabric, metal foil, etc. are used as the high-strength sheet. As the paper, any paper that can be fused and pressed with the paper-like material that is the constituent material of the present invention, such as Western paper, paperboard, Japanese paper, laminated paper, coated paper, and synthetic paper, and that can continuously produce a laminated sheet, can be used. The main purpose of these laminated sheets is to use them in applications that do not require transparency, such as trays for electronic components, carrier tapes, etc., so paper that itself does not easily generate dust, such as synthetic paper or so-called dust-free paper, is preferred. preferable. In order to facilitate fusion bonding with paper, it may be desirable to previously form perforations using electrical discharge or to perform surface treatment using known techniques. As for the metal foil, for example, aluminum foil coated with a hot melt adhesive or a solution type adhesive can be used. There are no restrictions on the nonwoven fabric, but a wet nonwoven fabric with little fuzz is preferred. The conductive laminated sheet of the present invention has sufficient peel strength and is comparable to those obtained by laminating transparent conductive films by dry lamination or extrusion coating. The conductive laminated sheet of the present invention can be divided into sheets that are entirely transparent or translucent film-like, and sheets in which only the conductive film layer is transparent. Next, a method for laminating a paper-like material obtained by making paper by a conventional method from a paper stock made of synthetic pulp mixed with conductive fibers onto a film as a high-strength sheet will be explained based on the attached drawings. . In FIG. 1, 1 is a paper-like material, 1' is a transparent conductive film layer, 2 is a preheating device, 3 is a high-strength sheet,
4 is a carrier, 5 is a heating roll, 6 is a bottom roll, 7 is a cooling device, 8 is a laminated sheet, 9 is a series of guide rolls, and 10 is a presser roll. Further, reference numerals 11, 12, and 13 are partially enlarged sectional views showing overlapping states of paper-like materials, carriers, laminated sheets, etc., and laminated states at respective positions. The paper-like material 1 is supported by a carrier 4 that is fed out almost simultaneously, and is preheated or preheated and compressed by a preheating device 2. Next, while the press roll 10 prevents the paper-like material from fluttering, the paper-like material is further preheated by the heating roll 5 and enters the nip with the bottom roll 6. The separately fed high-strength sheet 3 is overlapped with the paper-like material between the nips of the rolls 5 and 6. Preheating is performed by known means such as heating rolls, infrared heaters, hot air, etc., and the temperature and time are adjusted so that the synthetic pulp is melted and the individual conductive fibers are sufficiently coated with the resin of the synthetic pulp. The illustrated method is normally carried out at a speed of 5 to 50 m/min, but in the case of low speeds, the preheating device 2 is omitted, and the preheating time is the time required for the paper-like material to enter between the nips of rolls 5 and 6 from the presser roll. It is also possible to do this. However, carbon fibers and metal fibers have poor wettability with molten resin, so if heating and pressurization is performed after the heating is insufficiently preheated, the cushioning effect of the molten resin is small, resulting in breakage of the conductive fibers. This makes the resistivity of the conductive film layer non-uniform, which is undesirable. Organic conductive fibers, organic conductive processed fibers, etc. are difficult to break, but the fibers may be twisted, and in extreme cases, the specific resistance value may become non-uniform. If preheating or preheating compression is not performed or is insufficient, in addition to the above-mentioned drawbacks, moisture and air bubbles in the paper-like material cannot be completely removed, reducing the transparency of the conductive film layer and causing pinholes. This makes it difficult to achieve the object of the present invention. Compression during preheating is generally performed between rolls, but rapid compression is undesirable as it brings about the disadvantages mentioned above, and if necessary, a line of 10 kg/cm or less, preferably 5 kg/cm or less is used. Do it with pressure. The paper-like material is plasticized by preheating or pre-heat compression and turns into a translucent film, but it becomes cloudy and non-uniform due to residual air bubbles. Since this plasticized translucent film cannot maintain dimensional stability, a carrier is used. As the carrier, known films, papers, and sheet-like materials having good releasability, smoothness, repeated use, heat resistance, etc. are selected and used depending on the purpose. For example, thermoplastic synthetic pulp SWP UL410 (manufactured by Mitsui Petrochemical, polyethylene type, melting point 123℃, fiber length 0.9mm, specific gravity 0.94)95
Weight% (97% by volume) and pitch carbon fiber (trade name Kureha Carbon Fiber Tip, graphite fiber manufactured by Kureha Chemical Industry, fiber length 5mm, diameter 12.5μm, specific gravity 1.6) 5% by weight (3% by volume) basis weight consisting of
When laminating a 45.5 g/m ² paper-like material and a commercially available low-density polyethylene film (thickness 70 μm) at a processing speed of 5 m/min, the preheating temperature is 134°C, and the heating and pressing conditions are set to 140°C. Good results are obtained by using a polyester film (thickness 100 μm) as a carrier at a temperature of 40 Kg/cm and a linear pressure of 40 Kg/cm. In addition, known materials such as Teflon film, so-called releasable process paper coated with a release agent such as silicone resin, and a stainless steel belt can be used. The heating and pressing roll is composed of two or more rolls including the heating roll 5, and a calender used in the paper industry, a supercalender, a calender for plastics, etc. can be used. Regarding the heating temperature, in the case of the above example, the temperature at which the paper-like material becomes a transparent film (change from 1 to 1') and the fusion and pressure bonding temperature are the same. However, if the melting points of the two materials do not match, for example, Can's Film 101 (trade name, manufactured by Steel Chemical Industry Co., Ltd.,
Nylon/Surlyn coextrusion film, thickness 50μm,
When using Surlyn's melting point of 220°C/96/105°C), it is possible to sufficiently press-bond it at a temperature of Surlyn's melting point of 96 to 105°C.
(from 1' to 1') at the same time, the temperature must also be higher than the melting point of SWP (123°C) in this case as well. In addition, pressurization has effects such as making interlayer adhesion of the laminated sheet uniform and increasing peel strength, increasing the contact efficiency between conductive fibers and reducing the specific resistance of the conductive film layer. Furthermore, according to the inventor's experiments, it is effective in improving the transparency of the transparent conductive film layer 1'. For example, the laminated sheet in the above example is a conductive laminated sheet that has an opacity of 5% or less and is almost as transparent as a normal transparent film, but when processed without pressure, the transparency becomes considerably lower. The opacity decreases to an average value of 15%, and cloudy areas appear in various places indicating the presence of air bubbles.
Furthermore, when a paper-like material with a polymerization mixing ratio of SWP/NBKP/carbon fiber of 70/25/5 was processed under the above heating and pressurizing conditions, the opacity was 15% even though wood pulp, which is difficult to become transparent, was blended. A transparent laminated sheet is obtained. That is, in the present invention, pressure during lamination is an essential requirement, and the composition of the paper-like material, the type of high-strength sheet,
A linear pressure of 20 to 200 kg/cm, preferably 40 to 200 kg/cm, depending on the type of carrier, heating pressure roll, etc., heating temperature, etc.
A linear pressure of 100 kg/cm is applied to create a transparent film and crimping at the same time. Between the roll nips, the paper-like material is sandwiched between the carrier and the high-strength sheet and heated and pressurized, and as a result of being laminated, after cooling, the paper-like material forms an overlapping layered structure as shown in partially enlarged sectional view 12.
However, it is preferable that the material be cooled while being pressurized by an appropriate pressure device (not shown) until the cooling is completed after the heating process. This is because since the transparent conductive film layer is in close contact with the smooth carrier surface, the generation of fine wrinkles is prevented and the laminated sheet of the present invention, which is glossy and has high commercial value, can be obtained. It should be noted that heating and pressurizing using a carrier in this manner not only has the above-mentioned preheating effect for its cushioning effect, but also prevents breakage and twisting of the conductive fibers. From this point of view, it is more desirable to use a steel roll coated with an elastic material such as asbestos or rubber as the bottom roll 6, which is a pair of the heating rolls. Note that it may be necessary to support the high-strength sheet with a carrier as well. Gas in the laminated sheet is completely removed by heating and pressurizing. After the lamination is completed, the laminated sheet and carrier are cooled by a cooling device 7, and then separated and wound up as a laminated sheet 8 of the present invention comprising a transparent conductive film layer 1' and a high-strength sheet 3. As a cooling method, air cooling, air blowing, and other known methods are used. The carrier can also be wound separately or used endlessly. Laminated sheets of paper-like materials and paper, nonwoven fabric, metal foil, etc. are manufactured in the same way, but paper is generally elastic, and the fusion and pressure bonding of paper-like materials forms an extremely strong laminate due to the so-called role anchor effect. Therefore, wrinkles in the conductive film layer are suppressed. The conductive laminate sheet of the paper-like material and low-density polyethylene film exemplified above has a basis weight of 110 g/m ² , a thickness of 112 μm, an opacity of 5% or less, and exhibits the same transparency as the low-density polyethylene. Ta. The surface resistance was 2.92×10 ³ Ω, and the specific resistance of the conductive film layer was 1.81×10 ¹ Ω·cm. The peel strength was as high as 330 g/10 mm (Tatsupi Standard T517), and as a result of lamination, the mechanical strength was significantly improved. The method of the present invention has been described above with respect to the case of fusion bonding using a calender or the like, but the present invention is not limited to this. It also includes methods that have the same technical idea. Therefore, it can also be used to laminate a single conductive film and a high-strength sheet that have already been manufactured.
As a result, it is possible to produce a laminate sheet that is free of wrinkles and has high gloss. Note that a laminated sheet structure in which transparent conductive film layers are laminated on both sides of a high-strength sheet layer can also be produced by the method of the present invention. As explained above, according to the present invention, conductive laminated sheets can be continuously manufactured by simultaneously making paper-like materials transparent and laminating them. Furthermore, it is also possible to provide a high-strength laminated sheet having a thin transparent conductive film layer with a small basis weight. In addition, since a small amount of conductive fibers are uniformly dispersed in the transparent conductive film layer while maintaining the fiber length during raw material preparation, the specific resistance of the conductive film layer is stable and is less than 1×10 ⁸ Ω・cm. . The transparent conductive laminated sheet of the present invention has excellent transparency, and since it has transparency even when laminated with paper or the like, clear printing can be performed, and furthermore, any of the sheets can be heat-sealed. In the conductive laminate sheet according to the present invention, a desired specific resistance can be obtained by changing the blending ratio of the conductive fibers, and the specific resistance is mainly 10 ⁸ to ^{10 0} Ω・cm.
Those with a resistance of ¹⁰⁰ Ω·cm or less are suitable for applications that require electromagnetic shielding effects. The laminated sheet of the present invention can be formed into a desired shape by a known hot forming technique. The present invention will be explained below based on examples.
The present invention is not limited to these examples. Note that the resistance value was measured in accordance with the ASTM D257 method or the SRIS method. In addition, the specific resistance of the conductive layer of the laminated sheet is the same as that of the corresponding single conductive film (i.e., a single conductive film produced by heating and pressing under the same conditions as the method of the present invention except that the paper-like material is laminated with a high-strength sheet). It was calculated using the thickness of one conductive film). Example 1 SWP UL410 (manufactured by Mitsui Petrochemicals, polyethylene resin, melting point 123°C) (hereinafter referred to as synthetic pulp)
SWP) and thermoplastic composite fiber Daiwabo Polypro NBF-E (manufactured by Daiwabo Co., Ltd., core-sheath type polypropylene composite fiber, core component crystalline polypropylene, sheath component polyolefin polymer, sheath component melting point 96-100℃) (hereinafter referred to as (abbreviated as NBF),
As the carbon fiber, Kureha Carbon Fiber Tip C-203 (manufactured by Kureha Chemical Industry, graphite fiber, average fiber length 3.0 mm, single yarn diameter 12.5 μm) (hereinafter abbreviated as CF)
Using a conventional method, adjust the raw materials and make SWP/
Mixing ratio of NBF/CF 80/15/5 each weight% (82/
The paper stock was adjusted to 15/3 (each volume %). A base paper was produced using a test machine with a target weight of 45 g/m ² . When drying the base paper, the melting point of SWP is 123℃, which is higher than the melting point of NBF's sheath component, which is 96-100℃.
It was carried out at a lower temperature of 100-115°C. Manufacturing speed is
It was 30m/min. The resulting base paper was a white sheet with a smooth texture. In order to confirm the transparency of this base paper, a single conductive film was prototyped under the same conditions as the method of the present invention, except that it was not laminated with a high-strength sheet. A polyester film (manufactured by Diafoil Co., Ltd., thickness 100 μm) (hereinafter referred to as PET film) was used as the carrier, preheated to 134°C, and heated under pressure at 50 kg/cm at 134°C to create a transparent film. did. The paper passing speed was 5 m/min.
Because a carrier was used, the base paper could be made into a transparent film without tearing. Table 1 shows its physical properties. Next, a conductive laminated sheet was manufactured by the method of the present invention using the above base paper in order to be laminated on the high-strength sheet Can's Film. Preheating temperature to 134℃ using PET film when manufacturing single conductive film
The heating and pressurizing conditions were 140°C and 50 kg/cm.
The physical properties of the obtained conductive laminate sheet are shown in Table 1 in comparison with a single conductive film.

【table】

[Table] As shown in Table 1, the opacity of the laminated sheet of the present invention was 5.0% or less, the same as that of a single film, and almost the same as that of an ordinary transparent plastic film. The mechanical strength is significantly improved, and the surface resistance and specific resistance of the conductive layer are at the same level as a single conductive film, and it has a beautiful appearance without wrinkles, making it an excellent film for packaging electronic components. It was hot. Example 2 Same SWP and NBF as Example 1 as synthetic pulp
and stainless steel fiber (length 5) as the conductive fiber.
mm, diameter 8μm, specific gravity 7.8, manufactured by Nippon Yakin) (hereinafter referred to as StF), the raw material was adjusted by a conventional method,
A paper stock with a mixing ratio of SWP/NBF/StF of 75/15/10 weight% (82.2/16.5/1.3 volume%) was prepared. A base paper was produced using a test machine under the same conditions as in Example 1, aiming at a basis weight of 50 g/m ² . Coextruded multilayer film DSF as high strength sheet
-410 (PE/saponified EVA/PE, basis weight 50g/
m ² , thickness 50 μm, opacity 5.0% or less, manufactured by Dainippon Ink and Chemicals), and the preheating and heating and pressing conditions were the same as in Example 1. The physical properties of the obtained conductive laminate sheet are shown in Table 2 in comparison with a single conductive film as in Example 1.

【table】

[Table] As shown in Table 2, the opacity of the laminated sheet of the present invention was no different from that of a single conductive film, and it was sufficiently transparent. The peel strength was sufficient, and the tensile strength was the sum of the tensile strengths of the single conductive film and DSF, which was approximately three times as strong as that of the single conductive film. Based on the resistance value, this product could be used satisfactorily for packaging in fields where electromagnetic shielding effects are required. Example 3 SWP and NBF and organic conductive processed fiber Thunderon SS-N (made by Nihon Kasuke Sensei, acrylic softening point 190-240℃, specific gravity 1.18, average fiber length 5mm, single yarn diameter 17.5μm, specific resistance 5.85× 10 ^-2 Ω・cm) (hereinafter referred to as SS−
The mixing ratio of N is 80/15/5% by weight (81/
15/4% by volume), and paper was made in the same manner as in Example 1 to produce a base paper. Similarly, SWP/
A base paper containing NBF/CF of 82/15/3% by weight (83/15/2% by volume) was produced. On the other hand, release paper (KOY-
11, manufactured by Shikoku Paper Co., Ltd., hereinafter abbreviated as KOY), were preheated, heated and pressurized in the same manner as in Example 1, and SWP/NBF/SS-N, KOY and
A conductive laminate sheet of SWP/NBF/CF and KOY was obtained. The characteristic values of the base paper, high-strength sheet, and conductive laminate sheet are as shown in Table 3.

[Table] In Table 3, the surface resistance of the release paper is shown as a reference value. All other resistance values are values for the conductive film layer surface or conductive paper (base paper). The obtained conductive laminate sheet is a tough sheet consisting of a glossy transparent conductive film layer and a release paper layer. The fact that each resistance value is lower in the laminated sheet than in the base paper is due to the effect of fusion bonding by the method of the present invention. The conductive laminated sheet of the present invention can be used as a conveying tape for use in automating the die bonding process for fixing electronic components such as semiconductor ICs to predetermined positions on a mounting board. The structure of conventional transport tapes is that adhesive paper is integrated with release paper and wound into a tape shape, and the release paper is punched out in a predetermined area and has a window frame for chip adhesion. It is provided. However, conventionally, when this tape-shaped winding is unwound by a feeding device and chips are automatically picked up, yield and productivity are reduced due to static electricity generation due to friction and static electricity problems such as dust adsorption. This was becoming a problem. In order to solve this problem, a chip conveying tape as shown in FIGS. 2 and 3 was made using the conductive laminated sheet of this example. FIG. 2 is a partially cutaway perspective view of the tape, and FIG. 3 is a sectional view taken along the line AA in FIG. 2. In the figure, 1' is a transparent conductive film layer, 3 is a release paper, 8 is a conductive laminated sheet, 14 is an adhesive paper, 15 is a window frame for chip adhesion, and 16 is a tape feed hole. The tape width was 30 mm, and the adhesive paper was crepe-processed paper with a square meter weight of 40 g. and,
When the chips were attached to a window frame and used as a transport tape, the generation of static electricity and the adsorption of dust were prevented, making it suitable for use. Example 4 A base paper was produced in the same manner as in Example 1 except that the mixing ratio of SWP/NBF/CF was 80/15/5% by weight (82/15/3% by volume). Basis weight of base paper: 49.1g/
^m2 , thickness 136μm, density 0.36g/ ^cm3 , surface resistance ¹⁰⁸
It was ＜Ω. Next, dust-free paper (trade name: Clean Paper, manufactured by Shikoku Paper Industries, basis weight: 80 g/m ² , thickness: 104 μm, density: 0.77 g/cm ³ , surface resistance: 10 ⁸ <Ω) was used as a high-strength sheet. After preheating, heating and pressing in the same manner as in Example 1, the mixture was cooled to obtain a conductive laminate sheet. This item has a basis weight of 129.1g/m ² ,
Thickness 125μm, density 1.03g/cm ³ , tensile strength 10.3
Kg/15mm, surface resistance 4.0×10 ³ Ω, specific resistance 2.4×
¹⁰¹ Ω·cm, and peel strength was 165 g/10 mm. When one A4 size sheet of this sheet was taken and kneaded together for 3 minutes, less than 100 pieces of dust with a size of 0.5 μm or less were removed. In addition, when this conductive laminated sheet was heat-sealed between conductive film layers to make a bag for storing ICs, it had an excellent anti-static effect, generated less dust, was hard to tear, and the paper surface was exposed. Printability and writability were also good. Example 5 A base paper having a mixing ratio of SWP/NBKP/CF of 70/20/10% by weight (73/21/6% by volume) was produced according to Example 1. Basis weight of base paper: 49.0g/
m ² , thickness 114 μm, and surface resistance 1.2×10 ³ Ω.
Neutral kraft paper (product name: MM) as a high-strength sheet
The paper used was made by Sanyo Kokusaku Pulp, had a basis weight of 56.7 g/m ² , a thickness of 85 μm, a tensile strength (vertical) of 5.49 Kg/15 mm, and a surface resistance of 10 ⁸ <Ω). A three-layer conductive sheet having transparent conductive film layers on both sides of a neutral kraft paper layer was produced under processing conditions similar to those in Example 1. This item weighs 154.7 cm.
g/m ² , thickness 164μm, density 0.94g/cm ³ , surface resistance
The resistance was 1.4×10 ² Ω, and the specific resistance was 8.4×10 ⁰ Ω·cm. Since this product has conductive film layers on both sides, it can be used as a bag for storing electronic components or as a molded tray, and has the effect of preventing static electricity from the outside.

[Brief explanation of drawings]

FIG. 1 is a diagram illustrating the steps of the method of the present invention, FIG. 2 is a partially cutaway perspective view of a tape for transporting semiconductor chips using the conductive laminated sheet of the present invention, and FIG.
The figure is a sectional view taken along the line AA in FIG. 2. In the figure, 1 is a paper-like material, 1' is a transparent conductive film layer, 2 is a preheating device, 3 is a high-strength sheet, 4 is a carrier, 5 is a heating roll, 6 is a bottom roll, 7 is a cooling device, and 8 is a laminated layer. 9 is a guide roll, 10 is a presser roll, 11 is a partially enlarged sectional view showing that the paper-like material 1 is supported by the carrier 4, and 12 is a partially enlarged sectional view showing that the carrier 4 is in contact with the laminated sheet 8. 13 is a partially enlarged sectional view of the laminated sheet 8; 14 is adhesive paper;
15 is a window frame for chip adhesion, and 16 is a tape feed hole.

Claims (1)

[Claims] 1 Conductive fibers with a fiber length of 1 to 40 mm are dispersed in a thermoplastic resin matrix, and the opacity is 30%.
A method for producing a laminated sheet comprising at least one transparent conductive film layer and one high-strength sheet layer exhibiting a specific resistance of 1×10 ⁸ Ω·cm or less,
A paper-like product made by mixing synthetic pulp made of thermoplastic resin and conductive fiber is preheated on a carrier selected from films, papers, and sheet-like products that have good peelability, smoothness, repeated use, and heat resistance. The paper-like material is then laminated with a high-strength sheet using a carrier, and heated and pressed continuously between rolls at a temperature higher than the melting point of the synthetic pulp and lower than the melting point of the conductive fibers. A method for producing a conductive laminate sheet, characterized in that the laminate sheet is formed by fusing and pressing, cooling and then separating the carrier.