JP2009110987A - Flexible printed circuit board, inlet sheet using the same, and rfid medium - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To improve the production speed, friction defective and variation in quality of RFID media by providing a flexible printed board suitably used for the RFID media used for a managing operation system (RFID system) for information. <P>SOLUTION: The flexible printed circuit board includes a biaxially stretched polyester film having, on a base layer, a thermal adhesive layer formed by co-extrusion and a coating layer formed on a thermal adhesive layer surface by coating, and a metal foil bonded to a coating-layer surface of the biaxially stretched polyester film. This flexible printed circuit board is characterized in that the base layer of the biaxially stretched polyester film has a melting point of 200-300°C, and the thermal adhesive layer is made of a polyester resin containing a wax. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a flexible printed wiring board, an inlet sheet using the flexible printed wiring board, and an RFID medium. The present invention also relates to a method for manufacturing RFID media.

In recent years, information management and operation systems (RFID systems) using cards and tags with built-in IC chips have become widespread. The RFID media used for these are generally called "IC cards" or "IC tags", and can record and retain a larger amount of information than conventional printing / writing and magnetic recording cards / tags. Since it is useful, it is used in various fields for managing and operating various information on people and goods.
Conventionally, polyvinyl chloride (PVC) has been mainly used as the plastic material constituting the RFID medium. In recent years, however, there has been a growing demand for alternative materials that do not use halogen elements from the viewpoint of environmental protection, and the mainstream of such materials has been replaced by polyester resins. As a sheet or film made of a polyester-based resin, it is a non-oriented sheet made of a copolymerized polyester (PETG) containing 1,4-cyclohexanedimethanol as a copolymerization component from the viewpoint of being amorphous and having processing characteristics close to PVC, or From the viewpoint of versatility, biaxially stretched polyethylene terephthalate (PET) films are mainly used.

[Problems of conventional technology]
In manufacturing RFID media using these sheets and films, another sheet or film is placed on one or both sides of the inlet sheet in which an IC chip or an antenna circuit is placed on the surface of the sheet or film, and hot By performing hot pressing with a melt adhesive or the like sandwiched therebetween, the laminate is obtained by melt bonding. However, this manufacturing method has several problems that are difficult to solve in terms of productivity and product performance.
The most important problem is productivity (production speed). That is, since the current manufacturing method is a process of pressing and manufacturing several to several tens of IC cards one after another, the number of units that can be manufactured per unit time is limited. To solve this problem, the number of sets to be stacked in a single press has been increased or the size of the press has been increased. It is several times to ten times, and it is probably difficult to cope with the explosive spread of RFID media expected in the future.
In addition, in terms of productivity, it is difficult to apply uniform pressure and temperature over the entire press surface due to the properties of the equipment and process of pressing, and there is also a problem that it is difficult to significantly reduce the incidence of defective products. This problem has been improved for some time by improving the design of electric circuits and improving heat resistance. However, it is necessary to respond to higher functions expected in the future, that is, miniaturization and complexity of circuits. Is probably difficult.

In addition, one of the problems in product performance is that individual RFID media have variations in antenna gain and thus in the communicable distance. This is because the current manufacturing method is a hot press bonding method using an adhesive, and it is difficult to strictly control the thickness of the adhesive layer, resulting in variations within or between lots of presses. It is. An RFID medium identified by a non-contact method is identified by an electrical communication between an antenna and a coil included therein and an external reader. The dielectric constant and dielectric loss of the material that occupies the space in the immediate vicinity of the antenna and coil are the factors that dominate these electrical characteristics, so the variation in the thickness of the adhesive layer varies the product performance. It is a decisive factor that causes
In the present invention, a flexible printed wiring board (hereinafter abbreviated as FPC) suitable as a member and an inlet sheet are used to manufacture RFID media in which the above three problems (production speed, defect rate, and quality variation) are improved. And an RFID medium configured using the same and a manufacturing method thereof.

[Conventional technology for improving base materials]
The following techniques are disclosed as conventional techniques related to the FPC of the present invention.
(1) An antenna coil structure for an IC card, the surface of which comprises a base material containing amorphous polyethylene terephthalate and a metal pattern formed in contact therewith. (For example, see Patent Document 1)
(2) An antenna coil structure for an IC card comprising a base material containing a vinyl chloride resin and a metal pattern formed in contact therewith. (For example, see Patent Document 2)
(3) An IC card substrate obtained by laminating a metal foil on a polyester resin film. (For example, see Patent Document 3)
(4) A thermal adhesive polyester film in which a thermal adhesive layer is laminated on the surface of the polyester resin film by coextrusion. (For example, see Patent Documents 4 and 5)
(5) A method for producing an IC card in which an IC chip is embedded in a laminated sheet obtained by laminating a buffer layer and an adhesive layer on the surface of a polyester resin film (see, for example, Patent Documents 6 and 7).

JP 2004-46362 A JP 2004-46360 A JP 2002-270975 A JP 2006-327190 A JP 2006-327191 A JP 2000-36024 A Japanese Patent Laid-Open No. 11-328340

In these documents, a method for efficiently manufacturing RFID media without using an adhesive is disclosed.
However, in the inventions described in Patent Documents 1 and 3, an amorphous polyethylene terephthalate film is used as a base material, or a biaxially stretched polyester film is amorphized by reheating to a melting temperature and adhered to a metal foil. Yes. For this reason, the structures and substrates of these inventions are substantially amorphous base materials. If the base material is amorphous, it will be softened and deformed when a high temperature is applied in the subsequent RFID media manufacturing process, so that it is difficult to continuously laminate by applying tension. Moreover, the heat resistance of the RFID media produced thereby is insufficient.

Moreover, the invention described in Patent Document 2 is composed of PVC, which is not preferable in terms of environmental suitability.
In addition, in the inventions described in Patent Documents 4 and 5, a polyester base material for RFID having both heat resistance and thermal adhesiveness is disclosed, but metal foil is laminated and etched to be used as an FPC for an antenna circuit. It was not considered. About these polyester base materials, it is possible to form an FPC circuit by thermally laminating and etching a metal foil on the surface thereof. However, since the surface of the metal foil is generally much smoother than the surface of the base material made of plastic resin, when the metal foil is laminated on these polyester base materials, the air leakage and slipperiness of the adhesive surface are insufficient. In some cases, the adhesive strength is reduced and wrinkles are generated.
In the inventions described in Patent Documents 6 and 7, the buffer layer and the adhesive layer are made thicker than the base material in order to embed the IC chip. Since the buffer layer and the adhesive layer have a low softening temperature, they are not preferable in the RFID media manufacturing process and in terms of heat resistance, as in Patent Documents 1 and 3.
That is, in the prior art, a base material suitable for manufacturing FPC by a continuous laminating process without using an adhesive and manufacturing RFID media by using the continuous process has not been disclosed.

[Conventional technology for improving manufacturing methods]
The following prior art is disclosed as a method of manufacturing RFID media related to the present invention.
(5) IC tag roll manufacturing method in which wiring is printed on a roll-shaped material and IC is loaded (see, for example, Patent Document 6)
(6) IC card manufacturing method using roll-shaped IC card material (for example, see Patent Document 7)
(7) An IC card manufacturing method in which a plastic sheet is supplied between two belts and heated with a heating roll, and then adhered in a continuous pressing process using liquid oil as a pressure medium (see, for example, Patent Document 8)
(8) IC card manufacturing method in which upper and lower laminate films are bonded with a laminate roll (for example, see Patent Document 9)
(9) IC card manufacturing method in which a cover sheet is bonded to the surface of a circuit module via an adhesive, roll pressed at low temperature and low pressure, and then statically pressed at high temperature and high pressure (see, for example, Patent Document 10)
(10) A method of manufacturing an IC card having a uniform thickness of an adhesive layer by using an ultraviolet curable resin as an adhesive, flattening the adhesive layer by roll pressure, and then irradiating with an ultraviolet ray (for example, Patent Document 11) See
(11) A method of manufacturing an IC card in which a reactive adhesive is applied to a roll-shaped sheet material, an IC chip is encapsulated and then sandwiched between the sheet materials, and the adhesive is reacted and cured (for example, see Patent Document 12)
(12) A method for manufacturing an IC card in which a resin layer having a low softening temperature is coated on the surface of the IC card substrate in advance, and then a plastic film or an adhesive layer is laminated (see, for example, Patent Document 13)

JP 2005-259091 A JP 2001-229361 A JP-A-10-217658 JP-A-8-216574 JP 2000-57295 A Japanese Patent Laid-Open No. 10-175388 JP 2005-332384 A Japanese Patent Application Laid-Open No. 11-111173

In these documents, a method for manufacturing RFID media in a continuous manufacturing process is temporarily disclosed, and a manufacturing method for improving productivity is shown once.
However, the method of Patent Document 6 does not discuss a method of manufacturing a film by laminating films and the like, and the methods of Patent Documents 8, 11, and 12 eventually improve the productivity and cause defects due to manufacturing by a pressing process. The rate cannot be sufficiently reduced, and the methods of Patent Documents 7 and 9 to 13 use an adhesive, so it is difficult to improve the unevenness of the thickness of the adhesive layer, resulting in variations in production speed, defect rate, and quality. No technology that could improve everything was proposed.
In other words, in the prior art, production is performed by using a web-like biaxially stretched polyester film in which an adhesive layer has been formed in advance by coextrusion and using a laminate roll bonding process that does not have a pressing process, without using an adhesive. No RFID media manufacturing method has been disclosed that can improve speed, defect rate, and quality variations. In addition, the technology that improves the dielectric properties of RFID media by making the thickness of the adhesive layer uniform by forming the adhesive layer by coextrusion, and the technology that improves the defect rate by the laminating process that does not go through the pressing process There is no description or suggestion, and no technology has been proposed that can improve all of the production speed, defect rate, and quality variation in the manufacturing method.

  An object of the present invention is to provide an FPC suitable for use in RFID media, and to provide an RFID media with improved production speed, defective product generation rate, electrical quality, and product appearance, and a method for manufacturing the same. .

The present invention that can solve the above-described problems has the following configuration.
[1] A biaxially stretched polyester film in which a base layer is formed with a heat-adhesive layer formed by coextrusion and a coating layer formed by coating on the surface of the heat-adhesive layer; A flexible printed wiring board made of a metal foil, wherein the base layer of the biaxially stretched polyester film has a melting point of 200 to 300 ° C., and the thermal adhesive layer is made of a polyester resin containing wax. Flexible printed wiring board.
[2] The flexible printed wiring board according to [1] or [2], wherein the base material layer of the biaxially stretched polyester film is a white polyester film containing a white pigment or fine cavities therein.
[3] The flexible printed wiring board according to [1] or [2], wherein the thermal adhesive layer comprises a mixture of an amorphous polyester resin A, a thermoplastic resin B incompatible with the amorphous polyester resin A, and a wax. .
[4] The flexible printed wiring board according to [3], wherein the thermal adhesive layer has all the following features (1) to (4).
(1) The glass transition temperature of the amorphous polyester resin A is 50 to 95 ° C.
(2) The thermoplastic resin B is any of a crystalline resin having a melting point of 50 to 180 ° C., an amorphous resin having a glass transition temperature of −50 to 150 ° C., and a mixture thereof.
(3) 1-30 mass% of thermoplastic resin B is contained in the thermal adhesive layer.
(4) The thickness of the heat bonding layer is 5 to 30 μm.
[5] A coating layer is formed by applying a coating solution made of a resin having an adhesion start temperature of 160 ° C. or lower to one side of a polyester film that has been stretched uniaxially, and is further stretched in a direction perpendicular to the uniaxial stretching direction after coating The flexible printed wiring board according to any one of [1] to [4], which is formed.
[6] A flexible print in which another resin film is bonded and laminated on the coating layer surface or the heat bonding layer surface exposed by etching the metal foil of the flexible printed wiring board according to any one of [1] to [5] Wiring board.
[7] An RFID media inlet sheet in which an integrated circuit is arranged on the flexible printed wiring board according to [1] to [6].
[8] RFID media configured using the inlet sheet of [7].
[9] In a method for producing a flexible printed wiring board having a step of continuously laminating a web-like film wound up in a roll shape and a metal foil, a wax formed by co-extrusion as a web-like film. A flexible, characterized by using a biaxially stretched polyester film in which a base layer having a melting point of 200 to 280 ° C. is used as a thermal adhesive layer comprising a polyester resin and a coating layer formed by coating on the surface of the thermal adhesive layer Manufacturing method of printed wiring board.
[10] In an RFID media manufacturing method including a step of continuously laminating a plurality of web-like films wound up in a roll shape and a flexible printed wiring board or an inlet sheet, [1] to [7] A method for producing RFID media, comprising using the flexible printed wiring board or the inlet sheet described above.
[11] The RFID media manufacturing method according to [9], wherein the antenna circuit is disposed on the biaxially stretched polyester film coating layer of the flexible printed wiring board or the inlet sheet according to any one of claims 1 to 7. .

By using the FPC, inlet sheet, and RFID media manufacturing method of the present invention, it is possible to reduce high productivity, low defect rate, and variation in electrical quality, which cannot be achieved by the conventional manufacturing method.
[Main configuration and effects]
Since the FPC of the present invention uses a biaxially stretched polyester film provided with a thermal adhesive layer and a coating layer as a base material, there is no need to apply or laminate an adhesive layer in the thermal laminating process or its pre-process. The manufacturing process can be simplified.
In addition, since the FPC of the present invention is manufactured by etching a metal foil adhered to the film surface with an adhesive layer (thermal adhesive layer and coating layer), the portion from which the metal foil has been removed by etching functions as an adhesive layer again. To do. Therefore, it is not necessary to apply the adhesive again when the RFID medium or the flat cable is manufactured by laminating this on another resin film or the like, and the production process can be simplified.
In addition, the FPC of the present invention is manufactured by adhering a metal foil while maintaining the oriented crystal structure of the polyester molecules that is characteristic of the biaxially stretched polyester film (while maintaining the melting point of the polyester film at 200 to 300 ° C.). Therefore, it is excellent in mechanical strength and heat resistance, and can be continuously supplied to the heat laminating process as a web-like film. In addition, the thermal deformation of the processed IC card or IC tag can be improved to a practically acceptable range.

Further, the adhesive layer (thermal adhesive layer and coating layer) in the present invention is preferably stretched together when the web-like film is stretched and produced. As a result, the thickness of the adhesive layer is superior and uniform compared to processing by extrusion laminating or solution coating. It is possible to prevent, that is, reduce the variation in the communication distance. The stretched and oriented thermal adhesive layer is a strong adhesive layer and exhibits strong adhesiveness because molecules are oriented even if it is amorphous.
Moreover, the biaxially stretched polyester film used in the FPC of the present invention has a coating layer formed by coating on a substrate. Since it is stretched at least in a uniaxial direction after coating, it is superior and uniform compared to processing by extrusion lamination or solution coating, and excellent adhesiveness can be obtained without impairing planarity.

Further, the biaxially stretched polyester film used in the FPC of the present invention is made of a crystalline polyester resin containing no halogen. Therefore, in addition to being excellent in environmental suitability when used for RFID media, it is excellent in heat resistance and chemical resistance.
In addition, the biaxially stretched polyester film used in the FPC of the present invention contains an appropriate amount of wax in the thermal adhesive layer. Thereby, slipperiness improves and generation | occurrence | production of the wrinkle at the time of heat-bonding metal foil can be reduced. Moreover, the required adhesive strength can be obtained.
In the manufacturing method of the present invention, the RFID film is manufactured by continuously laminating the web-like film regardless of the pressing process, so that the production speed is dramatically higher than that of the sheet-by-sheet pressing that is currently widely performed. Can be improved.

In addition, since the biaxially stretched polyester film is used as the web-like film in the production method of the present invention, it can be laminated at a high temperature and is markedly superior to an unstretched sheet made of an amorphous resin having poor heat resistance. High-speed mass production processing is possible.
Moreover, in the manufacturing method of this invention, since it laminates continuously with a heated roll, it is easy to adjust uniformly temperature and pressure distribution of the whole surface to be bonded. Uniform temperature and pressure distribution is limited by mechanical accuracy, and compared to conventional processes that require readjustment of temperature and pressure for each press process, the thermal performance of IC chips and electrical circuits・ The frequency of mechanical damage can be reduced.
Moreover, in the manufacturing method of this invention, it is possible to acquire sufficient adhesive strength in low temperature and a short time by combining a heat bonding layer and an application layer. Thereby, high-speed laminating can be performed, and the production speed can be remarkably improved.

[Other configurations and effects]
As a base material layer of the biaxially stretched polyester film used in the FPC of the present invention, many fine cavities can be contained in the film by a known technique for producing a void-containing polyester film. This is a technique that has been difficult with conventional PVC and PETG sheets. This makes it possible to adjust the apparent density of the heat-adhesive polyester film, that is, the void content, and thus the cushioning properties and flexibility of the film, to an appropriate range when used for RFID media.
Appropriate inclusion of fine cavities in the base material layer of the biaxially stretched polyester film is effective for imparting light weight, flexibility, cushioning properties, and writing properties to the RFID media. Further, RFID media using a cavity-containing polyester film as a material has a low specific gravity and does not sink immediately even when dropped in water or in the sea. Therefore, accidents that lose media can be avoided in many cases. The void-containing polyester film has an apparent dielectric constant lower than that of a polyester film or sheet that does not contain voids. Therefore, dielectric loss is small in communication using high frequency in the HF band or SHF band. That is, RFID media using a void-containing polyester film as a material has a high gain and is effective in communication accuracy, communication distance, and power saving.

In addition, the biaxially stretched polyester film used in the FPC of the present invention has a heat-adhesive layer with an appropriate thickness mainly composed of an amorphous polyester resin. Therefore, the etched metal foil (antenna circuit) is buried in the thermal bonding layer by the thermal bonding process, and the unevenness is reduced, so that the appearance and yield of the RFID product can be improved.
In addition, the biaxially stretched polyester film used in the FPC of the present invention has a thermal adhesive layer made of a mixture of an amorphous polyester resin and a thermoplastic resin and wax incompatible with the amorphous polyester resin. For this reason, the thermal adhesive layer exposed by removing the metal foil by the etching process has a coefficient of static friction of 0.1 to 0.6, and when manufacturing the inlet sheet and when manufacturing the RFID media using the inlet sheet Blocking can be improved. In addition, by adjusting the amount of thermoplastic resin added to the amorphous polyester resin, the glass transition temperature, and the melting point to appropriate ranges, the friction coefficient is reduced and air escape is promoted without hindering thermal adhesion. The appearance after bonding and the product yield can be improved.
Moreover, in the heat-bonding layer of the biaxially stretched polyester film used in the FPC of the present invention, the protrusions formed by the thermoplastic resin hardly fall off even if they are large protrusions, and there is little risk of causing process contamination. . In addition, even when a low thermal bonding temperature is used, the thermal adhesiveness is softened and deformed and flattened during thermal bonding, resulting in a decrease in thermal adhesiveness caused by the addition of conventional inorganic and organic particles with large particle sizes. Does not occur. Further, since the likelihood of deformation is larger than that of inorganic / organic particles, there is little concern that the strength of the film will be reduced.

In addition, the biaxially stretched polyester film used in the present invention can obtain the necessary flatness when used as a constituent material of RFID media. This adjusts the thickness of the thermal adhesive layer and the thickness of the web-like film, and controls the heat shrinkage rate and linear expansion coefficient on the front and back of the film to an appropriate range, thereby reducing curling that occurs in post-processing steps. This is because.
Furthermore, the biaxially stretched polyester film used in the present invention is also suitable for constituting the exterior or intermediate layer of RFID media. By using this as an extrapolation or intermediate layer, necessary electrical components and circuits can be reliably included. This is because the present invention has a heat-adhesive layer that softens and deforms moderately during heat-adhesion processing, and a polymer having a melting point and a glass transition temperature that does not hinder it in the heat-adhesion layer. This is because it is contained as a dispersion. That is, this is because the biaxially stretched polyester film used in the present invention has a formability that reliably absorbs irregularities such as an IC chip and a metal foil circuit while maintaining slipperiness.

In the FPC of the present invention, a biaxially stretched polyester film in which a coating layer composed of a thermal adhesive layer and a coating layer formed by co-extrusion is formed on a base material layer, and a laminate composed of a metal foil adhered to the coating layer surface of the film In the FPC manufactured by etching the body, the biaxially stretched polyester film has a melting point of 200 to 300 ° C., and the thermal adhesive layer contains a wax.
Further, in the FPC of the present invention, it is a more preferable embodiment that the resin film is laminated on the coating layer surface or the heat bonding layer surface exposed by the etching process,
Moreover, in FPC of this invention, it is more preferable embodiment that the base material layer of a biaxially stretched polyester film is a white polyester film containing a white pigment or a fine cavity in the inside.

  In the FPC of the present invention, the thermal adhesive layer of the biaxially stretched polyester film is made of a polyester resin containing wax. The polyester resin is preferably an amorphous polyester. More preferably, the thermoadhesive layer of the biaxially stretched polyester film is composed of a mixture of the amorphous polyester resin A, the thermoplastic resin B incompatible with this, and a wax, and the two surfaces of the biaxially stretched polyester film are overlapped. It is more preferable that the static friction coefficient measured together is 0.1 to 0.6. Moreover, it is more preferable that the static friction coefficient measured by superimposing both front and back surfaces of the film obtained by removing the metal foil by etching the FPC is 0.1 to 0.6.

In the FPC of the present invention, the thermal adhesive layer provided on the biaxially stretched film preferably has a thickness of 5 to 30 μm and a glass transition temperature of 50 to 95 ° C. The thermoplastic resin B comprises (a) a crystalline resin having a melting point of 50 to 180 ° C., (b) an amorphous resin having a glass transition temperature of −50 to 150 ° C., ( It is c) or those mixtures, and it is more preferable embodiment that it is 1-30 mass% containing in a heat bonding layer.
In the FPC of the present invention, the coating layer provided on the biaxially stretched polyester film may be a resin having a softening temperature of 160 ° C. or less formed after coating through a drying step, a stretching step, and a heat setting treatment step. This is a more preferred embodiment.

In the RFID media inlet sheet of the present invention, it is a preferred embodiment that an IC is arranged on the FPC.
Moreover, it is preferable that the RFID media of the present invention is configured using the above inlet sheet.
In addition, in the RFID media manufacturing method of the present invention, in the RFID media manufacturing method including a step of laminating a plurality of web-like sheets wound up in a roll shape and continuously laminating them, It is a more preferred embodiment that the above FPC or inlet sheet is used to manufacture by an adhesion process using a laminate roll that does not have a pressing process.
In the RFID media manufacturing method of the present invention, it is a more preferable embodiment that an adhesive layer is not disposed as a layer adjacent to the antenna circuit. That is, it is a more preferable embodiment that the antenna circuit is disposed on the surface of the biaxially stretched polyester film coating layer of the flexible printed wiring board or the inlet sheet of the present invention.
Hereinafter, embodiments of the present invention will be described in more detail.

[Flexible printed circuit board]
The FPC of the present invention is an FPC produced by etching a laminate comprising a biaxially stretched polyester film having a heat bonding layer and a coating layer, and a metal foil bonded to the coating layer surface. The melting point of the biaxially stretched polyester film is observed at 200 to 300 ° C.
As a material of the metal foil used here, a metal having a small electric resistance such as silver, copper, gold, and aluminum can be used. However, since a circuit is formed by an etching process, copper or aluminum that can be easily etched is preferable. Used. Further, the thickness of the metal foil is not particularly limited, but is preferably 5 to 100 μm from the viewpoint of workability in the FPC manufacturing process, process stability, electrical performance, and cost, and 10 to 50 μm. It is more preferable that Moreover, it is preferable that it is 15-60 micrometers from a viewpoint of absorbing the unevenness | corrugation of metal foil (antenna circuit).

  The method of adhering the metal foil to the biaxially stretched polyester film is not particularly limited except that it is a method by thermal bonding, but as a method that is usually widely used, heat press bonding by a heat press or heat lamination by a heating roll is used. Adhesion can be used. In hot press bonding, there is an advantage that even a thick metal foil can be bonded reliably by applying a high pressure, but it is more preferable to bond by hot lamination because there is a limit in improving the production rate and reducing the defective rate.

The method of forming a circuit by etching this metal foil is not particularly limited as long as it does not cause significant damage that impairs the function of the biaxially stretched polyester film bonded to the metal foil or its thermal adhesive layer. Absent. For example, when a copper foil or an aluminum foil is used as the metal foil, a known method using a ferric chloride aqueous solution can be used.
Moreover, in this invention, after processing as FPC, it is necessary for a biaxially stretched polyester film to show melting | fusing point in the range of 200-300 degreeC. A conventionally known FPC produced using a biaxially stretched polyester film is bonded by heating to a temperature exceeding the melting point of the polyester resin constituting the substrate in order to heat laminate and bond the metal foil. Although these conventional FPCs exhibit sufficient performance in terms of adhesion, since the polyester film of the base material is substantially amorphous, the process of manufacturing RFID using FPC or RFID or FPC products As a result, the heat resistance is insufficient. That is, when unrolling from a roll and laminating with another resin sheet in a later process, it is difficult to apply sufficient tension due to softening of the base material, or deformation due to environmental temperature when used as RFID or FPC May occur.

  When the biaxially stretched polyester film exhibits a melting point of 200 to 300 ° C. after being processed as FPC, more preferably 250 to 300 ° C., the original oriented crystallized structure of the biaxially stretched film is sufficient. These problems are maintained, and these problems caused by insufficient heat resistance can be prevented. Setting the melting point in the above range means that a biaxially stretched polyester film comprising a polyethylene terephthalate resin or a polyethylene naphthalate resin, a polytrimethylene terephthalate resin, and a copolymer polyester resin having these as a basic skeleton as a biaxially stretched polyester film. This can be done by not heating to a temperature above the melting point when processing this as an FPC.

  Further, in the FPC of the present invention, an adhesive layer (a thermal adhesive layer and a coating layer, but depending on the etching processing conditions, the coating layer may also be etched and only the thermal adhesive layer may be present) on the portion where the metal foil has been removed by the etching process. Exposed. Since this exposed adhesive layer maintains thermal adhesiveness, it can be FPC, inlet sheet, and RFID media by thermal bonding with other resin sheets and films without using an adhesive. Since the product thus configured does not use an adhesive, it is possible to reduce variations in electrical characteristics, that is, dielectric constant and dielectric loss. When a resin sheet or film is bonded and laminated on the exposed coating layer surface or heat bonding layer surface, the adhesive strength is preferably 1 to 50 N / cm, and more preferably 3 to 20 N / cm. When the adhesive strength is less than this range, when used as a product such as an FPC or RFID media, the product may be broken due to bending or friction, which is not preferable. In addition, when it exceeds this range, no particular problem occurs, but it is not preferable because the adhesive strength exceeds the strength of the base material itself, resulting in excessive quality. In addition, as a method of adjusting the adhesive strength to this range, in addition to designing the adhesive layer appropriately as described later, the temperature at the time of thermal bonding is adjusted in the range of the adhesion start temperature to 200 ° C. of the coating liquid. Is possible.

  Further, the biaxially oriented polyester film used in the present invention preferably has a static friction coefficient of 0.1 to 0.6 when the front and back surfaces are opposed to each other, and is 0.3 to 0.5. It is more preferable. When the coefficient of static friction is less than this range, the slipperiness is too high, and handling of the FPC becomes difficult when it is stacked and stored or when it is wound into a roll, causing load collapse or winding deviation. . In addition, when the static friction coefficient exceeds the above range, blocking may occur when the cut FPC is handled in a sheet or wound into a roll.

[Inlet sheet and RFID media]
An inlet sheet is an intermediate product for manufacturing RFID media, which includes an antenna circuit formed of a conductor such as metal on the surface of a film substrate, and a capacitor or IC connected to the antenna circuit.
The inlet sheet of the present invention is obtained by arranging the above-described electronic component on the FPC of the present invention as an antenna circuit. The configuration is not particularly limited, but it is preferable that an adhesive layer (a thermal adhesive layer and a coating layer, although there may be only a thermal adhesive layer by etching treatment) is exposed on at least one surface thereof. . Since the exposed adhesive layer maintains thermal adhesiveness, the RFID medium can be configured by thermally bonding with another resin sheet or film without using an adhesive. Since the product thus configured does not use an adhesive, it is possible to reduce variations in electrical characteristics, that is, dielectric constant and dielectric loss. When a resin sheet or film is bonded and laminated on the exposed coating layer surface or heat bonding layer surface, the adhesive strength is preferably 1 to 50 N / cm, and more preferably 3 to 20 N / cm. When the adhesive strength is less than this range, when used as a product such as an FPC or RFID media, the product may be broken due to bending or friction, which is not preferable. In addition, when it exceeds this range, no particular problem occurs, but it is not preferable because the adhesive strength exceeds the strength of the base material itself, resulting in excessive quality. In addition, as a method of adjusting the adhesive strength to this range, in addition to designing the adhesive layer appropriately as described later, the temperature at the time of thermal bonding is adjusted in the range of the adhesion start temperature to 200 ° C. of the coating liquid. Is possible.

The RFID medium of the present invention is not particularly limited as long as it uses the inlet sheet of the present invention, but is obtained by laminating and bonding another resin sheet or film to the inlet sheet of the present invention. The resin sheet and film to be laminated are not particularly limited, but are preferably a sheet or film made of a polyester resin from the viewpoint of environmental suitability, and biaxially stretched polyester from the viewpoint of heat resistance, chemical resistance, mechanical strength, and the like. Is more preferable, and a white polyester film containing a white pigment or fine cavities therein is more preferable.
Laminating and using a white polyester film is a preferred embodiment because it can improve the concealability and whiteness of RFID media. This makes it possible to produce beautiful media when printing is performed on the surface, and it is possible to enhance security by hiding the built-in electronic components and electrical circuits. Moreover, it is the most preferable embodiment to use a film containing fine cavities inside. The effect of the micro-cavity gives the RFID media a cushioning effect to protect the internal circuitry, and the RFID can be supple and improve the handling. Immediately when writing a sign on a card. Many advantages can be obtained, such as reducing the dielectric constant and dielectric loss and increasing the communicable distance of RFID. Moreover, when laminating a biaxially stretched polyester film by thermal bonding, it is effective to use a film having an adhesion improving layer on the surface for improving the adhesive strength.

[Composition of film]
The FPC of the present invention is characterized by using a biaxially stretched polyester film in which an adhesive layer comprising a thermal adhesive layer and a coating layer is formed. This biaxially stretched polyester film will be described in detail.
The biaxially stretched polyester film used in the present invention comprises a base material and a structure in which a thermal adhesive layer and a coating layer are laminated on one side or both sides of the base material. As the substrate, it is important to use a biaxially stretched polyester film from the viewpoints of environmental suitability (not including a halogen compound), heat resistance, chemical resistance, strength, rigidity, and the like. As a result, these characteristics are remarkably improved as compared with non-oriented PVC sheets and PETG sheets that have been conventionally used.
In addition, it is important that the biaxially stretched polyester film used in the present invention has a thermal adhesive layer on one side or both sides. The thermal adhesive layer here is a layer that can be thermally bonded to a plastic film or sheet, a metal film, and various coating layers formed on the surface of the IC card or IC tag under heating conditions. By laminating this thermal adhesive layer on the substrate, the same thermal adhesiveness as PVC, PETG or the like, which is a material of a conventional IC card or IC tag, can be imparted. It is important that the thickness of the thermal adhesive layer is 5 to 30 μm per layer. When the thickness of the thermal adhesive layer is less than 5 μm, the thermal adhesiveness and the unevenness absorbability are insufficient. On the other hand, when the thickness of the thermal adhesive layer exceeds 30 μm, the heat resistance and chemical resistance are lowered as in the case of a card using a conventional PETG sheet as a material. The lower limit of the thickness of the heat bonding layer is preferably 8 μm, and more preferably 10 μm. On the other hand, the upper limit of the thickness of the heat bonding layer is preferably 25 μm and more preferably 20 μm.

As a means for providing a thermal adhesive layer on the surface of the base material, a method of extruding a melted raw material to produce an unstretched sheet, a method of laminating and extruding two kinds of resins in a molten state, a so-called coextrusion method is used. Use. Since the thermal adhesive layer laminated by this method has a small variation in thickness at each part in the plane, the variation in dielectric properties at each part is smaller than that of an adhesive layer made of an adhesive or the like, and an FPC or RFID manufactured using this It is possible to improve the electrical characteristics of the media, and thus the leakage current phenomenon and communication distance.
In the biaxially stretched polyester film used in the present invention, it is a preferred embodiment to provide a thermal adhesive layer on both sides of the substrate from the viewpoint of suppressing curling of the film. In the present invention, the thermal adhesive layer is mainly composed of an amorphous resin, and the thermal expansion coefficient is greatly different from that of a base material mainly composed of a crystalline polyester resin. For this reason, when a thermal adhesive layer is provided only on one side of the base material, it may curl like a bimetal depending on processing conditions and use conditions, and there is a concern about poor flatness and handling properties. When providing a heat bonding layer on both surfaces of a base material, it is preferable that the thickness ratio of the heat bonding layer of the front and back is in the range of 0.5-2.0. When it is out of this range, curling may occur due to the above reason. Even when curling occurs, if the curl value after heat treatment at 110 ° C. for 30 minutes in a no-load state is 5 mm or less, there is no substantial hindrance to handling properties. More preferably, the curl value is 3 mm or less, and particularly preferably 1 mm or less.

  As another method for suppressing curling, there is a method in which the temperature and heat quantity given to the front and back surfaces of the film are positively differentiated, and as a result, the curl value is brought close to zero. Specifically, in the stretching process such as longitudinal stretching and lateral stretching, and the heat setting process, the degree of orientation of the front and back surfaces of the film is controlled independently by setting the temperature or the amount of heat on the front and back of the film to different values. Balance the structure and physical properties of the front and back surfaces. As a result, curling can be reduced. When this method is used, in the heating / cooling process of the step of longitudinally stretching the film, it is easy to adjust the temperature of the roll or infrared heater for heating the front and back surfaces of the film, which is a preferable method.

  The biaxially stretched polyester film used in the present invention preferably has a total film thickness of 25 to 350 μm. The lower limit of the thickness of the entire film is more preferably 38 μm and even more preferably 50 μm. Further, the upper limit of the thickness of the entire film is more preferably 280 μm, further preferably 200 μm. When the thickness of the whole film is less than 25 μm, the mechanical strength, the handleability, and the process stability at the time of manufacturing the FPC and RFID media are not preferable. On the other hand, when the thickness of the entire film exceeds 350 μm, the combination with other sheets, films, and electric circuits within the standard thickness of the RFID media (for example, 0.76 mm for the IC card in the JIS standard) It is not preferable because it is limited.

[Adhesive layer (thermal adhesive layer and coating layer)]
The FPC of the present invention is characterized by using a biaxially stretched polyester film having an adhesive layer composed of a thermal adhesive layer and a coating layer on a substrate.
By providing the thermal adhesive layer, the unevenness absorbability and the adhesive strength can be improved. The above can maintain the formability by absorbing irregularities when introducing an antenna circuit and an IC chip. As will be described later, when softened by heat, the metal surface can be indented and the adhesion area between the metal and the coating solution can be increased (anchor effect).
Moreover, adhesion with a metal, a resin sheet, and a film can be improved by providing an application layer. The thermal adhesive layer has thermal adhesiveness and can be bonded to a metal, a film, or the like by an anchor effect. When the coating layer is provided here, in addition to the anchor effect, a chemical bond is formed between the metal and the resin that is the main component of the coating layer, so that stronger adhesive strength can be obtained. Therefore, it is desirable to provide a coating layer in addition to the thermal bonding layer for bonding the IC chip or antenna circuit to the film.

[Thermal bonding layer]
In the FPC of the present invention, it is important to use a biaxially stretched polyester film in which a thermal adhesive layer is formed as a substrate, and it is important that this thermal adhesive layer contains a wax.
These waxes include synthetic polymer wax agents such as polyolefin resins, polyester resins, polyether resins, acrylic resins, and silicone resins, as well as natural mineral waxes such as montan wax, and carbana waxes. However, it is important to have heat resistance because it is processed together with the polyester resin. Of these, synthetic polymer waxes are preferably used, and polyolefin waxes are more preferable from the viewpoints of softening temperature, surface tension, and handleability.

  Here, as a method of adding a wax to the thermal adhesive layer, in addition to directly adding the wax as described above, a resin component such as a polyethylene resin (PE), a polypropylene resin (PP), or a polyethylene glycol resin (PEG) is added. As a result, it is also possible to contain a low molecular weight component contained in the resin as a wax. The appropriate amount of the wax to be contained varies depending on the type of the wax, and it is difficult to limit it generally. For example, when a polyolefin-based wax or a polyethylene glycol resin is used, the amount of the wax contained in the heat-adhesive layer is 0. 03-3 mass% is preferable and 0.1-0.8 mass% is more preferable. Moreover, when adding a polyethylene resin and utilizing the low molecular-weight component as a wax, it is preferable to add 1-20 mass% as a polyethylene resin, and it is more preferable to add 3-10 mass%. Appropriate amounts of addition with other waxes can be designed with an amount of addition that increases the coefficient of static friction by about 0.1 to 0.5 when the film surface is thoroughly wiped with acetone. is there.

Moreover, it is preferable to use a wax having a melting point of 40 to 150 ° C, more preferably 50 to 120 ° C. When the melting point is less than this range, the melt extrusion process becomes unstable, a heat-degraded product is likely to be produced, or the film is bleed and deposited, which is not preferable. On the other hand, if the melting point exceeds this range, the effect of reducing friction is reduced, and thermal adhesiveness is hindered.
Moreover, it is preferable that an amorphous polyester resin A whose heat amount of fusion is 20 mJ / mg or less is a main constituent of the thermal adhesive layer. Here, the heat of fusion is the heat of fusion measured by heating at a rate of 10 ° C./min in a nitrogen atmosphere using a DSC apparatus in accordance with “Method for measuring the transition heat of plastic” described in JIS-K7122. . In the present invention, the heat of fusion is preferably 10 mJ / mg or less, and more preferably no melting peak is observed. In the case where the heat of fusion is 20 mJ / mg or less, the heat bonding layer is easily deformed in the heat bonding process, absorbs irregularities such as metal foil and electronic parts better, and has excellent flatness, such as an FPC or an inlet sheet, RFID media can be provided.

  Further, it is important that the amorphous polyester resin A has a glass transition temperature of 50 to 95 ° C. The above-mentioned glass transition temperature is obtained by heating at a rate of 10 ° C./min in a nitrogen atmosphere using a DSC apparatus according to “Method for measuring plastic transition temperature” described in JIS-K7121. It means the midpoint glass transition temperature (Tmg) determined based on the curve. The lower limit of the glass transition temperature of the amorphous polyester resin A is preferably 60 ° C and more preferably 70 ° C. On the other hand, the upper limit of the glass transition temperature is preferably 90 ° C, more preferably 85 ° C. When the glass transition temperature is less than 50 ° C., it is deformed due to insufficient heat resistance when used as an FPC or RFID medium, or the thermal adhesive layer is peeled off by slight heating. On the other hand, when the glass transition temperature exceeds 95 ° C., it is necessary to heat at a higher temperature when manufacturing FPC and RFID media, which reduces the production speed and increases the burden on the electric circuit. It is not preferable.

  The type of the amorphous polyester resin A is not particularly limited, but from the viewpoint of versatility, cost, durability, and thermal adhesiveness to a PETG sheet, various types of copolymer are used in the molecular skeleton of the aromatic polyester resin represented by polyethylene terephthalate. What introduce | transduced the polymerization component is used preferably. Among the copolymer components to be introduced, examples of the glycol component include ethylene glycol, diethylene glycol, neopentyl glycol (NPG), cyclohexanedimethanol (CHDM), propanediol, and butanediol. On the other hand, examples of the acid component include terephthalic acid, isophthalic acid, and naphthalenedicarboxylic acid. As the copolymer component, a monomer that can lower the glass transition temperature and improve the thermal adhesiveness at a low temperature is selected. Examples of such a copolymer component include a glycol having a long linear component or a component having a non-linear structure having a large steric hindrance. The latter component is used when it is desired to improve the unevenness absorbability by effectively reducing the crystallinity of the thermal adhesive layer. In the present invention, from the viewpoint of thermal adhesiveness to the PETG sheet, CHDM and NPG are preferable, and NPG is more preferable.

  In addition, as the amorphous polyester resin A, there are some which are generally developed for adhesive use and are commercially available. When such an adhesive resin is used, since it was originally developed as an adhesive, there is a possibility that it can be bonded to a wide range of materials. However, it may be difficult for such an adhesive resin to be stably coextruded in the production process of a biaxially stretched film. If the co-extrusion is not stably performed, the variation in the thickness of the thermal bonding layer, which is one of the essential points of the present invention, is not sufficiently reduced, and the electrical characteristics of the IC card and the IC tag are impaired. . In such a case, it is necessary to make the thickness distribution of the thermal adhesive layer uniform by sufficiently adjusting the temperature of the extruder and the thickness of the thermal adhesive layer.

  In the present invention, the thermal adhesive layer includes the amorphous polyester resin A and the amorphous or crystalline thermoplastic resin B incompatible with the amorphous polyester resin A, and forms a sea / island structure. preferable. The thermoplastic resin B exists as a dispersion (island structure) in the thermal adhesive layer. In addition, the protrusion caused by the island structure of this sea / island structure imparts slipperiness to the heat-adhesive polyester film, and the protrusion is crushed and flattened in the heat bonding process, and does not impair the heat adhesion. Has a working effect.

Hereinafter, an amorphous thermoplastic resin and a crystalline thermoplastic resin that can be used as the thermoplastic resin B will be described.
The amorphous thermoplastic resin that can be used as the thermoplastic resin B is a thermoplastic resin having a heat of fusion of 20 mJ / mg or less. The heat of fusion is measured by heating at a rate of 10 ° C./min in a nitrogen atmosphere using a DSC apparatus in accordance with JIS K 7122 “Method for measuring the transition heat of plastic”.
The amorphous thermoplastic resin forms an island structure in the amorphous polyester resin inside the thermal adhesive layer, and protrusions resulting from this form on the surface of the thermal adhesive layer. This protrusion needs to maintain sufficient hardness at room temperature to improve the slipperiness of the film. Therefore, in the present invention, when an amorphous thermoplastic resin is used as the thermoplastic resin B serving as an island component, it is important that the glass transition temperature of the resin is −50 to 150 ° C. In addition, said glass transition temperature is the intermediate-point glass transition temperature measured in the heating process of 10 degree-C / min in nitrogen atmosphere with the DSC apparatus according to "the plastics transition temperature measuring method" shown by JISK7121. means.

The lower limit of the glass transition temperature of the amorphous thermoplastic resin is preferably −20 ° C., more preferably 0 ° C. If the glass transition temperature of the amorphous thermoplastic resin is less than −50 ° C., the slipperiness required when handling the film cannot be obtained, or the thermoplastic resin component is not present after manufacturing the FPC or RFID media. May exude to the surface.
In addition, the projections due to the sea / island structure are flattened and flattened in the thermal bonding process, and work so as not to disturb the thermal adhesiveness. In the present invention, the lamination performed when manufacturing the FCP and RFID media is preferably performed at 100 to 200 ° C. Therefore, the upper limit of the glass transition temperature of the amorphous thermoplastic resin is more preferably 130 ° C, and further preferably 100 ° C or less. On the other hand, when the glass transition temperature of the amorphous thermoplastic resin exceeds 150 ° C., sufficient thermal adhesiveness cannot be obtained at the normal bonding temperature, and when heat bonding is performed at a higher temperature, an electric circuit, etc. There is a problem that the burden on

On the other hand, in the present invention, a crystalline thermoplastic resin can be used as the thermoplastic resin B used by adding to the thermal adhesive layer. As the crystalline thermoplastic resin, a thermoplastic resin having a heat of fusion exceeding 20 mJ / mg is used. In addition, the heat of fusion is measured by heating at a heating rate of 10 ° C./min in a nitrogen atmosphere using a DSC apparatus according to “Method for measuring transition heat of plastic” described in JIS K7122.
Since this crystalline thermoplastic resin is incompatible with the amorphous polyester resin A, an island structure is formed as a dispersion in the amorphous polyester resin, and protrusions resulting from this form on the surface of the thermal adhesive layer. Is done. This protrusion needs to maintain the hardness at room temperature and improve the slipperiness of the film. Therefore, it is important that the crystalline thermoplastic resin has a melting point of 50 ° C to 200 ° C. The melting point of the crystalline thermoplastic resin is measured by heating at a rate of 10 ° C./min in a nitrogen atmosphere using a DSC apparatus according to “Method for measuring plastic transition temperature” described in JIS K 7121. Is done.
The lower limit of the melting point of the crystalline thermoplastic resin is more preferably 70 ° C, further preferably 90 ° C. Moreover, in order to make it work so that adhesion | attachment may not be inhibited by being crushed and flattened in the process of thermal bonding, it is not preferable that the melting point of the resin exceed the maximum temperature in the thermal bonding process by 30 ° C. More specifically, the upper limit of the melting point of the resin is more preferably 180 ° C, and even more preferably 160 ° C.

In the present invention, the thermoplastic resin used for the thermal adhesive layer is not particularly limited, but is used by mixing with an amorphous polyester resin, so that it does not dissolve in the amorphous polyester resin. PC), acrylic resins, cyclic olefin resins (COC) and their copolymers, low density stereoregular low density polypropylene and polyethylene (LDPE, LLDPE) such as olefins and their copolymers, etc. Polystyrene and polyolefins are more preferable because of their high stability against ultraviolet rays, ultraviolet rays, and oxygen, and more general use, and polystyrene or cyclic olefin copolymers are more preferable from the viewpoint of high heat resistance.
Examples of the crystalline and highly versatile resin include polyethylene (PE), polypropylene (PP), polybutadiene (PB), polyethylene propylene rubber (EPR), polylactic acid (PLA), and polyoxymethylene (POM). It is done. Among these, polyethylene or polypropylene is preferable because of its high stability to heat, ultraviolet rays, and oxygen, and polyethylene is more preferable, and polyethylene is more preferable because of its appropriate melting point. The polyethylene is preferably high-density polyethylene or linear low-density polyethylene having a density exceeding 0.90 g / cm ³ in terms of crystallinity.

Moreover, in this invention, the quantity of the thermoplastic resin B contained in a thermobonding layer is 1-30 mass% with respect to the material which comprises a thermobonding layer. 3 mass% is preferable and, as for the minimum of content of the thermoplastic resin B, 5 mass% is more preferable. On the other hand, the upper limit of the content of the thermoplastic resin B is preferably 25% by mass, and more preferably 20% by mass. When the content of the thermoplastic resin B is less than 1% by mass, the necessary slip properties cannot be obtained. On the other hand, when the content of the thermoplastic resin B exceeds 30% by mass, it becomes a coarse projection, and when it falls off from the surface of the film, on the contrary, the slipperiness becomes worse, or it is sufficiently flattened by the thermal bonding process. Otherwise, the thermal adhesiveness may deteriorate.
Moreover, in this invention, it is preferable that the maximum height of the surface of a heat bonding layer is 1.0-10 micrometers. The lower limit of the maximum height of the surface of the thermal adhesive layer is more preferably 1.2 μm, and particularly preferably 1.5 μm. On the other hand, the upper limit of the maximum height of the surface of the thermal adhesive layer is more preferably 8.0 μm, and particularly preferably 5.0 μm. When the maximum height of the surface of the heat bonding layer is less than 1.0 μm, sufficient slipping property cannot be obtained, and the handling property of the film becomes difficult. On the other hand, when the maximum height of the surface of the thermal adhesive layer exceeds 10 μm, the protrusions on the surface of the film fall off due to rubbing, thereby contaminating the process, and conversely, the slipperiness is deteriorated.

Moreover, in this invention, it is preferable that ratio (St1 / Sa1) of the maximum height (St1) of the surface of a heat contact bonding layer and arithmetic mean surface roughness (Sa1) is 3.0-20. The lower limit of St1 / Sa1 is more preferably 5.0, and particularly preferably 7.0. On the other hand, the upper limit of St1 / Sa1 is more preferably 16, and particularly preferably 12. When St1 / Sa1 is less than 3.0, it becomes difficult to improve slipperiness. On the other hand, when St1 / Sa1 exceeds 20, it becomes difficult to obtain thermal adhesiveness.
As a method for adjusting the maximum height of the protrusions on the surface of the thermal adhesive layer to an appropriate range, (1) a method for selecting the melt viscosity and glass transition temperature of the amorphous polyester resin A, and (2) a thermoplastic resin B And a method of selecting the melt viscosity, glass transition temperature, melting point, surface tension, solubility parameter, and addition amount, and (3) a method of selecting the temperature at which the resin of the thermal adhesive layer is extruded onto the film surface. Among these methods, a method of adjusting the glass transition temperature of the amorphous polyester resin, the type and addition amount of the thermoplastic resin, and the extrusion temperature is easy and reliable.

Further, in the present invention, the maximum protrusion height on the surface of the heat bonding layer after the surface of the heat bonding layer is sandwiched between a smooth and clean glass plate and subjected to hot press treatment (100 ° C., 1 MPa, 1 minute). The thickness (St2) is preferably 0.001 to 3 μm. The lower limit of St2 is more preferably 0.005 μm, and most preferably 0.01 μm. Further, the upper limit of St2 is more preferably 2.5 μm, and most preferably 2 μm or less.
When St2 is less than 0.005 μm, the resin constituting the heat-adhesive layer flows during the heat lamination, which may result in insufficient processing stability. Moreover, when St2 exceeds 0.01 μm, many protrusions remain even after thermal bonding, and an adhesive interface sufficient to exhibit stable adhesive force cannot be obtained, which is not preferable. In order to adjust St2 within the range of 0.001 to 3 μm, the melting point of the crystalline thermoplastic resin is adjusted within the range of 50 to 200 ° C., or the content of the crystalline thermoplastic resin is adjusted to 1 to 30. It is effective to adjust within the mass% range.

Moreover, in the heat-adhesive polyester film used by this invention, it is preferable that the surface and the back surface of a film are made to oppose, and the static friction coefficient in the interface is 0.1-0.6. The lower limit of the friction coefficient is more preferably 0.2. On the other hand, the upper limit of the friction coefficient is more preferably 0.7, still more preferably 0.6, and particularly preferably 0.5. It is difficult within the scope of the present invention to make the coefficient of static friction between the front and back surfaces of the film less than 0.1. On the other hand, when the static friction coefficient exceeds 0.8, the handling property of the film is remarkably deteriorated. In order to adjust the static friction coefficient in the range of 0.1 to 0.8, as described above, the maximum height of the surface of the thermal adhesive layer is adjusted, and the elastic modulus and surface tension of the thermal adhesive layer are adjusted. It is preferable to adjust.
Further, as a method for adjusting the static friction coefficient to the above range, a wax is added to the thermal adhesive layer. Since the thermal adhesive layer is amorphous, the elastic modulus is low and the viscosity is relatively high. In such a heat-bonding layer, a wax is added because the friction coefficient cannot be sufficiently reduced even if incompatible thermoplastic resin, inorganic particles, or organic particles are added.

In addition, unevenness due to an IC chip or the like disposed in the electric circuit on the FPC or inside the RFID medium is absorbed by the thermal adhesive layer of the biaxially stretched polyester film used in the present invention. This unevenness absorbability can be expressed by parameters of a shaping rate and a gradient of the outer edge of the shaped part as a measure of the shaping property by the heat bonding process. Here, the shaping rate means that the antenna circuit or the copper foil piece is placed on the surface of the thermal adhesive layer, hot pressed, and then removed from the antenna circuit or the copper foil piece at room temperature and normal pressure. Means the depth of the indentation of the heat-bonding layer, and the gradient of the outer edge of the shaped portion means the gradient of the wall surface at the outer edge of the indentation.
Moreover, in the biaxially stretched polyester film used by this invention, it is preferable that the shaping rate by hot press is 40 to 105%. In light of the fact that the present invention absorbs irregularities in IC chips and electrical circuits, the lower limit of the shaping rate is more preferably 50%, and even more preferably 60%.

  From this viewpoint, it goes without saying that the higher the upper limit of the shaping rate, the more ideal. However, if a resin that is extremely softened during heating is used as the thermal adhesive layer in order to increase the forming rate, there is a concern that the processing stability may decrease due to the thermal adhesive layer flowing in the thermal adhesive process. Actually, it is more preferable to keep it at 102% or less, and more realistically 98% or less. As a method for adjusting the shaping rate to 40 to 105%, the thickness of the thermal adhesive layer is adjusted to 5 μm or more, or the glass transition of the amorphous polyester resin A or the thermoplastic resin B constituting the thermal adhesive layer. Examples thereof include a method of bringing the temperature and melting point close to the thermal bonding temperature, and appropriately adjusting the mixing ratio, viscosity, elastic modulus and the like.

Moreover, in this invention, it is preferable that the gradient of the outer edge of the shaping part by a hot press is 20 to 1000%. In the present invention, from the viewpoint that the thermal adhesive layer absorbs the irregularities of the IC chip and the electric circuit, the shape of the indented shape preferably matches the outer shape of the electric circuit or the like. The case where the gradient of the outer edge of the shaped part is less than 20% means that the convex part of an electric circuit or the like is stretched around its periphery, or the shape of the convex part is not sufficiently absorbed. Means state. This gradient is more preferably 50% or more, and further preferably 100% or more.
Further, from the viewpoint of unevenness absorbability, it goes without saying that the larger the gradient of the outer edge of the shaped portion by hot pressing, the more ideal the deformation, and the geometrically infinite is most preferable. However, what is practically achieved in the technical scope disclosed in the present invention is up to the upper limit of 1000%, and what can be practically achieved by a more general processing step is 500% or less. In addition, as a method of adjusting the gradient of the outer edge of the shaped part by hot pressing within the range of 20 to 1000%, in addition to adjusting the thickness of the thermal adhesive layer to 5 μm or more, the amorphous property constituting the thermal adhesive layer Examples thereof include a method of appropriately adjusting the glass transition temperature, mixing ratio, viscosity, elastic modulus and the like of the polyester resin A and the amorphous thermoplastic resin B.

  In addition, in the biaxially stretched polyester film used in the present invention, a white pigment is preferably contained in the thermal adhesive layer, particularly when used as a card or tag material that is white and needs to be concealed. One. As the white pigment to be contained in the thermal adhesive layer, those composed of titanium oxide, calcium carbonate, barium sulfate and a composite thereof are preferable, and titanium oxide is more preferably used from the viewpoint of the concealing effect. These inorganic particles are preferably contained in a range of 30% by mass or less, more preferably 20% by mass or less, with respect to the constituent material of the biaxially stretched polyester film of the substrate. If added beyond the above range, the production process of the biaxially stretched polyester film will break and the production efficiency will be remarkably lowered, or the dielectric constant and dielectric loss of the film will rise, resulting in FPC and RFID. This is not preferable because the electrical characteristics of the film deteriorate.

  In the biaxially stretched polyester film used in the present invention, organic particles may be contained in the thermal adhesive layer as long as thermal adhesiveness, slipperiness and unevenness absorbability are not impaired. By including organic particles in the thermal adhesive layer, it is possible to form protrusions on the surface of the thermal adhesive layer, and when manufacturing FPC or RFID media by thermal adhesion by thermal lamination, bubbles between the films are formed. It becomes possible to discharge effectively. As the organic particles, melamine resin, cross-linked polystyrene resin, cross-linked acrylic resin and composite particles mainly composed of these are preferable. In addition, it is preferable to contain these inorganic particles in 30 mass% or less with respect to the constituent material of a heat bonding layer, and it is more preferable to set it as 20 mass% or less. When the addition exceeds the above range, it is not preferable because the production efficiency of the biaxially stretched polyester film may be remarkably lowered due to the breakage of the film.

[Coating layer]
The biaxially stretched polyester film used in the present invention is characterized by having an adhesive layer formed on the surface by coating. The purpose of forming the coating layer is to obtain stronger adhesive strength by the chemical bond formed between the metal and the resin that is the main component of the coating layer in addition to the anchor effect of the thermal bonding layer. .
The resin used for the coating layer is preferably a thermoplastic resin and contains a functional group capable of coordinating with a metal such as a hydroxyl group or a carboxyl group. Further, the contact angle between water and the biaxially stretched polyester film on which the coating layer is formed is preferably 80 degrees or less, more preferably 75 degrees or less, and further preferably 70 degrees or less. As a resin satisfying such conditions, a resin used for improving the adhesion of a normal polyester film such as a polyurethane resin, an acrylic resin, a polyolefin resin, a polyester resin, or a polyester urethane resin is preferably used, and more preferably a polyurethane resin. Polyolefin resin and polyester resin, more preferably polyurethane resin and polyolefin resin are used. Among these, since it immerses in an acid and a base solution in an etching process process and a resist peeling process process, resin excellent in hydrolysis resistance is more preferable.

Moreover, the resin which is the main component of the coating layer adheres to a substrate such as a film or metal by applying heat. Assuming that the lower limit of the bonding temperature at which the base material and the resin to be bonded have a peel strength of 3 N / cm or more is the bonding start temperature, the laminate is preferably carried out at 100 to 200 ° C. when manufacturing an FPC or RFID. The coating layer preferably has an adhesion start temperature of 130 ° C. or lower, and more preferably 100 ° C. or lower. When the adhesion start temperature of the coating layer exceeds 160 ° C., the resin of the coating layer is not sufficiently softened, resulting in poor adhesion.
The coating layer is formed through a drying process, a stretching process, and a heat setting process after coating the coating liquid in the biaxially stretched polyester film forming process. As a method for providing the coating layer, conventionally used methods such as a gravure coating method, a kiss coating method, a dip method, a spray coating method, a curtain coating method, an air knife coating method, a blade coating method, and a reverse roll coating method can be applied. As a step of applying, any method such as a method of applying before stretching of the film, a method of applying after longitudinal stretching, and a method of applying to the film surface after the orientation treatment is possible, but the flatness of the film is maintained. In view of the above, a method of stretching in at least a uniaxial direction after coating is preferable.

The thickness of the coating layer is preferably 0.005 to 1 μm, more preferably 0.01 to 0.5 μm, and most preferably 0.02 to 0.1 μm. If the thickness is less than this range, the adhesiveness cannot be maintained, which is not preferable. Moreover, when thickness exceeds this range, since the uneven | corrugated absorbability which a heat adhesive layer has falls, it is unpreferable.
In the preferred embodiment, the application surface is only one side of the biaxially stretched polyester film that does not contact the roll surface because the roll and the film adhere to each other when the application layer comes into contact with the heated roll surface.
The coating liquid does not impair the advantages of the biaxially stretched polyester film including concealability and cushioning properties. Moreover, since it is thinly applied on the biaxially stretched polyester film, it does not affect the unevenness absorbability. Moreover, since it is extended | stretched at least uniaxially after application | coating, the planarity of a biaxially stretched polyester film is not impaired.

[Base layer of biaxially stretched polyester film]
The biaxially stretched polyester film used in the present invention is based on at least one biaxially stretched polyester film layer. This layer can be easily adjusted in optical properties and mechanical properties by a conventionally known method.
When the biaxially stretched polyester film used in the present invention is used as a material for white or highly concealed FPC or RFID media, a cavity-containing polyester film containing a large number of fine cavities therein is preferred as the base film. The apparent density of the film is preferably controlled to 0.7 to 1.3 g / cm ³ by a large number of fine cavities inside the film. The lower limit of the apparent density of the film is more preferably 0.8 g / cm ^3, more preferably 0.9 g / cm ^3. The upper limit of the apparent density of the film is more preferably ^{1.2g / cm 3, 1.1g / cm} 3 is more preferred. When the apparent density of the film is less than 0.7 g / cm ³ , the strength, buckling resistance, and compression recovery rate of the film are lowered, and appropriate mechanical performance is obtained when manufacturing and using FPC and RFID media. It becomes impossible. On the other hand, when the apparent density of the film exceeds 1.2 g / cm ³ , flexibility, cushioning properties, and lightweight properties required for FPC and RFID media cannot be obtained.

  As a method for containing voids in the film, (1) a method in which a foaming agent is contained and foamed by heat during extrusion or film formation, or foamed by chemical decomposition, (2) carbon dioxide gas during or after extrusion (3) A method in which a polyester and an incompatible thermoplastic resin are added to the polyester, and the polyester is melt-extruded and then stretched uniaxially or biaxially (4) ) A method of stretching uniaxially or biaxially after adding organic or inorganic fine particles and melt-extruding can be mentioned.

Among the above-described methods for incorporating cavities in the film, the method (3) above, that is, a method in which a thermoplastic resin incompatible with polyester is added, and after melt extrusion, is stretched uniaxially or biaxially is preferable. . The thermoplastic resin incompatible with the polyester resin is not limited in any way, but is a polyolefin resin represented by polypropylene or polymethylpentene, a polystyrene resin, a polyacrylic resin, a polycarbonate resin, or a polysulfone resin. Examples thereof include cellulose resins and polyphenylene ether resins.
These thermoplastic resins may be used alone or in combination of a plurality of thermoplastic resins. The content of the thermoplastic resin incompatible with these polyester resins is preferably 3 to 20% by mass, more preferably 5 to 15% by mass with respect to the resin forming the void-containing polyester layer. And, if the content of the thermoplastic resin incompatible with the polyester resin is less than 3% by mass with respect to the resin forming the void-containing polyester layer, the void content formed inside the film is reduced, so that the concealing property is reduced. descend. On the other hand, when the content of the incompatible thermoplastic resin exceeds 20% by mass with respect to the resin forming the white polyester layer, breakage frequently occurs in the film manufacturing process. In addition, 10-50 volume% is preferable and the cavity content rate inside a cavity containing polyester film has more preferable 20-40 volume%.

d. When the biaxially stretched polyester film used in the present invention is used as a white or highly concealed FPC or RFID media material, a white polyester film containing a white pigment in a biaxially stretched polyester layer as a base film Is also one of the preferred embodiments. The white pigment used here is not particularly limited, but is preferably made of titanium oxide, calcium carbonate, barium sulfate and a composite thereof from the viewpoint of versatility, and more preferably titanium oxide from the viewpoint of the hiding effect. These inorganic particles are preferably contained in the range of 25% by mass or less, more preferably 20% by mass or less, with respect to the constituent material of the white polyester layer. When it is added beyond the above range, breakage frequently occurs during film production, and industrial-level stable production may be difficult.

In addition, when the biaxially stretched polyester film used in the present invention is used as a material for white or highly concealed FPC or RFID media, the content of fine cavities and white pigment is adjusted as appropriate so that the optical density is 0.5 to It is preferable to set it to 3.0. The lower limit of the optical density is more preferably 0.7, further preferably 0.9. Further, the upper limit of the optical density is more preferably 2.5, and further preferably 2.0. When the optical density is less than the above range, when an IC card or IC tag is used, the internal structure such as an IC chip or an electric circuit may be seen through due to insufficient concealment. It is not preferable in terms of security. In addition, in order to produce a film so that the optical density exceeds the above range, the content of fine cavities and white pigments inside the film must be extremely increased, and the film strength and the like are reduced.
When the biaxially stretched polyester film used in the present invention is used as a material for white or highly concealed FPC or RFID media, a method of forming a cavity by blending a thermoplastic resin that is incompatible with a polyester resin A method of combining a method of blending a white pigment is most preferable.

In the biaxially stretched polyester film used in the present invention, the base material layer excluding the thermal adhesive layer is preferably composed mainly of crystalline polyester. The crystalline polyester resin here is a polyester resin having a heat of fusion exceeding 20 mJ / mg. The method for measuring the heat of fusion is the same as described above.
Such crystalline polyesters include aromatic dicarboxylic acids or their esters such as terephthalic acid, isophthalic acid, naphthalenedicarboxylic acid, and ethylene glycol, diethylene glycol, 1,3-propanediol, 1,4-butanediol, neopentyl glycol, etc. Polyester produced by polycondensation with an appropriate amount of glycol. In addition to the direct weight method in which an aromatic dicarboxylic acid and a glycol are directly reacted, these polyesters can be transesterified by an alkyl ester of an aromatic dicarboxylic acid and a glycol and then subjected to a polycondensation, or an aromatic method. It can be produced by a method such as polycondensation of diglycol ester of dicarboxylic acid.
Representative examples of the crystalline polyester include polyethylene terephthalate, polytrimethylene terephthalate, polybutylene terephthalate, and polyethylene-2,6-naphthalate. The above polyester may be a homopolymer or a copolymer of a third component. When a resin whose crystallinity has been lowered by copolymerizing the third component is used, moderate deformation occurs in the thermal bonding process, and irregularities of the antenna circuit and integrated circuit appear on the product surface. Can be relaxed.

[RFID media manufacturing method]
In the RFID media manufacturing method of the present invention, a plurality of web-like films wound up in a roll shape are first laminated while being unwound. In the production by the press process generally used in the past, a base film is laminated in a single sheet, but in the method of the present invention, a web-like base material wound up in a roll shape is used, so that the handling property is greatly increased. In addition to the improvement, there is no need for a large storage space necessary for flat placement of the base sheet group, and there is a risk of collapsing during storage and handling, or introducing foreign substances between sheets. The complexity of the process can be greatly reduced.

Here, the inlet sheet of the present invention is used as one strip of a web-like film, and another resin sheet or film is laminated and bonded. The resin sheet and film are not particularly limited as long as they are continuous webs wound in a roll shape, and are biaxially stretched polyester films from the viewpoint of heat resistance, chemical resistance, environmental suitability, etc. of RFID media. Preferably there is. Moreover, it is preferable to use a white polyester film in terms of concealment and design among biaxially stretched polyester films, and a white polyester film containing fine cavities in terms of cushioning properties, lightness, flexibility, writing properties, etc. It is more preferable that
In addition, since the antenna circuit, the metal coil, and the IC chip are usually exposed in the inlet, a film having a thermal adhesive layer laminated on the surface thereof as used in the FPC of the present invention is used, and the thermal adhesive layer is made of these electrical circuits. It is also a more preferred embodiment to laminate them so as to protect them against the circuit. The thermal adhesive layer can be easily deformed in the thermal laminating process, and can effectively relieve unevenness caused by circuits and chips, thereby producing a card or tag with a beautiful appearance. Is possible.
In the present invention, laminating an adhesive sheet or the like is not preferable from the viewpoint of speeding up the processing, and laminating an adhesive layer as a layer adjacent to the antenna circuit is not preferable because it leads to variations in electrical characteristics. .

Further, in the RFID media manufacturing method of the present invention, the plurality of web-like films unwound as described above are continuously heat-laminated and bonded by a laminating roll bonding process that does not have a pressing process.
The laminate roll adhesion performed here is preferably performed by introducing a plurality of web-like films laminated on a pair of heated laminate rolls and pressing them at a temperature equal to or higher than the softening temperature of the thermal adhesive layer. In the present invention, since a biaxially stretched polyester film is used as the heat-adhesive film, it is possible to heat and bond to a temperature sufficiently higher than the heat-bonding temperature, and a conventionally known method for laminating unstretched sheet groups It is possible to bond at a higher temperature and faster than
Although it does not specifically limit as a heating roll for laminating, In order to reduce the adhesion of a heat bonding layer, it is preferable to use a heat resistant resin roll and metal rolls, such as silicone rubber. Moreover, in order to make the thermal bonding layer into a mirror finish, it is also preferable to use a mirror-plated metal roll or a roll plated with a chromium alloy.
When a polyester resin-based thermal adhesive layer is used as the temperature for bonding, it is necessary to perform the heating at a temperature higher than its glass transition temperature, preferably at 70 ° C. or higher, and at 90 ° C. or higher. It is more preferable for improving the adhesive strength.

In the present invention, since it is important to obtain an RFID medium that takes advantage of the characteristics (heat resistance, chemical resistance, dimensional stability, etc.) of the biaxially stretched polyester film, the bonding temperature is higher than the melting point of the polyester film. However, it is more preferable to carry out at 200 ° C. or lower, more preferably 160 ° C. or lower. When heating is performed above these temperatures, the above film characteristics are lost, the film may be deformed, the tension of the film being transported may fluctuate, and the RFID media produced may be curled. Therefore, it is not preferable.
The web-like film transported when laminating is heated and pressed by a laminating roll, but if heated rapidly with only a pair of rolls, temperature unevenness and accompanying adhesive unevenness and deformation may occur. It is also preferred to preheat before being introduced into the roll. The method for performing the preheating is not particularly limited, but in addition to the method for increasing the film temperature while sequentially passing the heated rolls, it is also possible to perform the preheating with a non-contact heater using hot air or infrared rays. From the standpoint of simplicity of the manufacturing apparatus, preheating with a heating roll is preferable, and a method using a non-contact heater is preferable for preventing deformation of the RFID medium and reducing the defect rate.
The web-like film conveyed to the laminate roll is preferably guided to the laminate roll in a state of being kept flat after preheating in order to prevent curling of the card or tag to be manufactured. For example, when a polyester film is used as the web-like film, it is preferable to perform lamination after unwinding so as to be kept flat at a temperature of approximately 70 ° C. or lower, which is lower than the glass transition temperature.

In addition, according to the manufacturing method of the present invention, it is possible to wind and store a web-like continuous body of RFID media heat-bonded with a laminate roll in a roll shape, or handle it. However, when the heat-bonded laminate is wound into a roll without being sufficiently cooled, curling that cannot be solved when used after cutting may occur. In order to prevent this, it is preferable to cool sufficiently while maintaining a flat surface before removing the tension after lamination. Although the target temperature for cooling is uniquely determined because it depends on the equipment conditions, etc., when a biaxially stretched polyester film is used as the web-like film, it is generally required to cool to 70 ° C. or lower, and to 50 ° C. or lower. It is more preferable to cool to room temperature.
It is preferable to apply a controlled tension to the web-like film conveyed during the lamination so as to maintain flatness. The tension applied at this time is preferably 1 N / m or more and more preferably 10 N / m or more from the viewpoint of maintaining flatness. Further, from the viewpoint of preventing the elastic deformation of the film and thus curling of the IC card or tag, it is preferably 1000 N / m or less, more preferably 200 N / m or less.

In addition, in order to improve the flatness of the IC card or IC tag by positively controlling the curl, it is possible to adjust the heating temperature on both sides during lamination so that a flat surface can be obtained as a result. Is possible. When the curl is caused by thermal expansion of the film bonded to the front and back, it is preferable to laminate by setting the heating temperature of the surface that becomes the inner side of the winding lower than that of the opposite surface.
Moreover, 0.1-20 MPa is preferable and the pressure at the time of thermal lamination has more preferable 0.3-10 MPa. If the pressure during thermal lamination is less than 0.1 MPa, the flatness of the card or tag is not sufficient, and a beautiful appearance cannot be obtained. On the other hand, when the pressure at the time of thermal lamination exceeds 20 MPa, even if a heat-adhesive polyester film using a void-containing polyester film as a base material is used, the excellent cushioning property and unevenness absorption effect are reduced by high pressure. . As a result, a burden on a circuit such as an IC chip becomes excessive, and an electrical failure is likely to occur.

One of the preferred embodiments of the RFID media manufactured in the present invention is a biaxially stretched polyester film (with an apparent density of 0.7 to 1) based on a cavity-containing film containing a large number of fine cavities inside the film. .3 g / cm ³ ), and an RFID medium having an apparent density of 0.7 g / cm ³ or more and less than 1.3 g / cm ³ . The lower limit of the apparent density is more preferably ^{0.8g / cm 3, 0.9g / cm} 3 is more preferred. The upper limit of the apparent density of the card or tag is more preferably ^{1.2g / cm 3, 1.1g / cm} 3 is more preferred. In addition, when the apparent density is less than 0.7 g / cm ³ , the strength, buckling resistance, and compression recovery rate of the RFID medium are lowered, and appropriate mechanical performance cannot be obtained during processing or use. On the other hand, when the apparent density of the card or tag is 1.3 g / cm ³ or more, lightness and flexibility as an RFID medium cannot be obtained. In addition, RFID media with an apparent density of 0.7 g / cm ³ or more and less than 1.3 g / cm ³ will have enough time to be collected before it floats on the water surface or sinks in the event of a submergence accident. be able to. For this reason, the card of this embodiment is suitable as a personal information recording card that an individual records the information and uses on a daily basis.

Next, the relationship between the technical requirements and effects of the present invention will be described in detail with reference to Examples and Comparative Examples. In addition, the characteristic value used by this invention was evaluated using the following method.
[Evaluation methods]
(1) Melting point of resin and glass transition temperature DSC measurement was performed according to "Method for measuring plastic transition temperature" described in JIS K7121. As the sample, about 10 mg of a small piece obtained by cutting a thermal adhesive layer from a film using a microtome with a magnifying glass, sealed in an aluminum pan, melted at 300 ° C. for 3 minutes, and quenched with liquid nitrogen was used. A differential scanning calorimeter (manufactured by Seiko Instruments Inc., EXSTAR 6200DSC) was used as a measuring instrument, and the measurement was performed under a dry nitrogen atmosphere. After heating from room temperature at a rate of 10 ° C./min to determine the midpoint glass transition temperature, the melting peak temperature (melting point) was determined.
(2) Heat of fusion of resin The amount of heat of fusion was determined according to “Method for measuring heat of transition of plastic” described in JIS K7122. The details of the DSC measurement were the same as those of the above melting point measurement.
(3) Intrinsic Viscosity of Polyester Resin According to "Plastics-Determination of viscosity of polymer diluted solution using capillary type viscometer-" described in JIS K 7367-5, phenol / 1,1,2,2-tetrachloroethane It measured at 30 degreeC using the mixed solvent of (60/40; mass part).

(4) Average particle diameter of particles The particles were observed with a scanning electron microscope (S2500, manufactured by Hitachi, Ltd.), and the magnification was appropriately changed according to the size of the particles, and a photograph was enlarged and copied. Next, the circumference of each particle was traced for at least 200 particles randomly selected. The equivalent circle diameters of the particles were measured from these trace images with an image analyzer, and the average value thereof was taken as the average particle diameter.
(5) Film thickness Measured according to “Method for measuring foamed plastic film and sheet—thickness” described in JIS K 7130. The measuring instrument used was an electronic micrometer (manufactured by Marl, Millitron 1240). Four 5 cm square samples were cut from arbitrary four locations of the film to be measured, and 5 points (20 points in total) were measured per sheet, and the average value was taken as the thickness.
(6) Lamination thickness of film A small piece was cut out from arbitrary three places of the film to be measured. The small piece was cut using a microtome to create a film cross section perpendicular to the film surface. A platinum-palladium alloy was sputtered onto the cross section to obtain a sample, and the cross section was examined using a scanning electron microscope (S2500, manufactured by Hitachi, Ltd.). The total thickness of the film was observed at an appropriate magnification included in one field of view, and the thickness of each layer was measured. The measurement was performed at three places for each field of view, and the average value of a total of nine places was used as the laminate thickness.

(7) Apparent density of film Five samples of 100 mm square cut out from five arbitrary points were measured by “Measurement of foamed plastic and rubber-apparent density” described in JIS K7222. The measurement was performed at room temperature, and the average value was used as the apparent density. In order to simplify the notation, the unit was converted to g / cm ³ .
(8) Curling value of the film The film to be measured was cut into a sheet shape of 100 mm in the longitudinal direction and 50 mm in the width direction from arbitrary three places, and after heat treatment at 110 ° C. for 30 minutes under no load, Standing on a horizontal glass plate with the convex part down, the vertical distance between the glass plate and the lower end of the four corners of the rising film was measured with a ruler in units of a minimum scale of 0.5 mm. The average value of the measured values was taken as the curl value. Three sheets were measured and the average value was taken as the curl value.

(9) Forming rate of film and gradient of outer edge of shaped part About the prepared FPC, the adhesive surface between the circuit and the thermal adhesive layer was carefully peeled off. A part of the thermal adhesive layer where the interface was peeled off was selected, and a three-dimensional image was obtained in the same manner as in (5) so that the step of the indentation of the circuit was included in the field of view. A cross-sectional profile perpendicular to the step of the indentation was obtained by the cross-sectional analysis function of the software. From this profile, the depth of the indentation by the printed circuit was obtained, and the shaping rate was obtained by dividing by the height of the original circuit. Further, in the outer edge portion of the indentation, a gradient (gradient at the approximately 1/3 portion of the step including the central portion of the step) was obtained for the step from the indentation portion to the non-indentation portion, and was used as the gradient of the shaping portion outer edge. In addition, observation was performed about 3 visual fields and the average value of a total of 15 profiles was evaluated.

(10) Optical density and light transmittance of film Using a transmission optical densitometer (Macbeth, RD-914), the optical density in white light was measured. Measurement was performed on five 50 mm square samples cut out from five arbitrary positions of the sample to be measured, and the average value was taken as the optical density.
(11) Coefficient of static friction of FPC Measured according to “Testing method of foamed plastic film and sheet—friction coefficient” described in JIS K 7125. A tensile tester (manufactured by Shimadzu Corporation, AG1KNI) was used as a measuring instrument. The front and back surfaces of the FPC sample to be measured were opposed to each other, the load applied to the sliding piece was 1,500 g, and the average value of five times in total was taken as the static friction coefficient.

(12) Peel strength of FPC For the prepared FPC or metal foil laminate, the peel strength of the metal foil and the film was measured by the method of JIS X 6305-1. In the examples, the case where the peeling at the adhesive interface did not occur and the film base material was destroyed was described as “material destruction” and judged to have sufficient adhesive strength (peeling strength).
(13) Appearance of FPC or RFID media The appearance of the prepared FPC or RFID media was visually evaluated. Observe irregularities caused by residual bubbles and wrinkles on the adhesive surface, significant warping, undulation (planarity), integrated circuits, etc., and "good" is acceptable for practical use, and "bad" for design problems. "
(14) Heat resistance of FPC or RFID media The prepared FPC or RFID media is allowed to stand on a clean and flat stainless steel plate (SUS304, thickness 0.8 mm), and is heated at 110 ° C. in an air atmosphere using an oven. Heated for an hour. Visually evaluate the appearance of samples before and after heating (loss of gloss, discoloration, cloudiness, cracks, deformation, melting, fusion), ○ if there is no difference between before and after heating, △ depending on the degree Or it was set as x.

(15) Defective product incidence of RFID media A communication test was performed on the produced RFID media using an RF-ID demo kit (L720-H01T-W001, manufactured by OMRON Software). The evaluation was made on 50 tags or cards to determine the incidence of defective products that could not be communicated. The case where the defective product occurrence rate was less than 1% was evaluated as ◯, the case where it was 1% or more and less than 5%, and the case where it was 5% or more as x.
(16) Communication distance variation of IC card or IC tag The produced IC tag or IC card was subjected to a communication test using an RF-ID demonstration kit (L720-H01T-W001, manufactured by OMRON Software). The end of 10 tags or cards was gripped with a non-metallic gripper, and the longest distance recognized by gradually approaching the receiving antenna from a distance of about 50 cm was measured. The average communication distance and the variation were obtained from the communication distance when the distance was recognized and when the distance was not recognized to the nearest distance.

The raw material resins and master pellets used in the examples are as follows.
[Polyethylene terephthalate resin (PET resin)]
A polyethylene terephthalate resin having an intrinsic viscosity of 0.62 dl / g, an Sb content of 144 ppm, an Mg content of 58 ppm, a P content of 40 ppm, and substantially free of inert particles and internally precipitated particles was used.
[Polyethylene naphthalate resin (PEN resin)]
Polyethylene naphthalate resin (PEN resin) with an intrinsic viscosity of 0.63 dl / g, Sb content of 250 ppm, Mg content of 58 ppm, P content of 40 ppm, and substantially free of inert particles and internal precipitation particles is used. did.

[Amorphous polyester resin]
Amorphous polyester resin A1: The glycol component is ethylene glycol / neopentyl glycol = 70/30 molar ratio, the intrinsic viscosity is 0.62 dl / g, the Sb content is 150 ppm, the Mg content is 60 ppm, and the P content is 40 ppm of copolymerized polyethylene terephthalate resin was used. Analysis of this resin by DSC apparatus showed no melting point and a glass transition temperature of 74 ° C.
Amorphous polyester resin A2: dicarboxylic acid component is terephthalic acid / naphthalenedicarboxylic acid = 60/40 molar ratio, intrinsic viscosity is 0.62 dl / g, Sb content is 150 ppm, Mg content is 60 ppm, P content A copolymerized polyethylene terephthalate resin containing 500 ppm of amorphous silica particles having a particle size of 40 ppm and 1.5 μm was used. Analysis of this resin by DSC apparatus showed no melting point and a glass transition temperature of 98 ° C.
Amorphous polyester resin A3: dicarboxylic acid component is terephthalic acid / sebacic acid = 90/10 molar ratio, glycol component is ethylene glycol / neopentyl glycol = 90/10 molar ratio, and intrinsic viscosity is 0.62 dl / g Copolymer polyethylene terephthalate resin having an Sb content of 150 ppm, an Mg content of 60 ppm, and a P content of 40 ppm was used. Analysis of this resin by DSC apparatus showed no melting point and a glass transition temperature of 52 ° C.

[Preparation of cavity forming agent-containing master pellets]
20% by mass of a polystyrene resin having a melt flow rate of 1.5 (manufactured by Nippon Polystyrene Co., Ltd., G797N), 20% by mass of a gas phase polymerization polypropylene resin having a melt flow rate of 3.0 (manufactured by Idemitsu Petrochemical Co., Ltd., F300SP), and a melt flow rate. 60% by mass of 180 polymethylpentene resin (manufactured by Mitsui Chemicals, TPX DX820) is mixed with pellets, supplied to a twin-screw extruder, kneaded thoroughly, and the strand is cooled and cut to contain a cavity forming agent-containing master pellet Adjusted.

[Preparation of titanium oxide-containing master pellets]
A mixture of 50% by mass of the above polyethylene terephthalate resin and 50% by mass of anatase-type titanium dioxide having an average particle size of 0.3 μm (electron microscopy) is supplied to a vented twin screw extruder and pre-kneaded, The molten polymer was continuously supplied to a bent type single-screw kneader and kneaded to prepare titanium oxide-containing master pellets.
[Preparation of wax-containing master pellets]
A mixture of 95% by mass of the above amorphous polyester resin A1 and 5% by mass of polyethylene wax (manufactured by Mitsui Chemicals, high wax NL500, melting point 105 ° C.) is supplied to a vent type twin screw extruder and supplied to 285 ° C. Were pre-kneaded. This molten polymer was continuously supplied to a single screw extruder and kneaded to prepare a wax-containing master pellet W1.
A mixture of 80% by mass of the above amorphous polyester resin A1 and 20% by mass of polyethylene glycol (produced by Toho Chemical Co., PEG10000, melting point 56 ° C.) is supplied to a vent type twin screw extruder and preliminarily prepared at 270 ° C. Kneaded. This molten polymer was continuously supplied to a single screw extruder and kneaded to prepare wax-containing master pellets W2.

(Example 1)
[Production of heat-adhesive biaxially stretched polyester film]
A mixture consisting of 8% by mass of the above-mentioned cavity forming agent-containing master pellets, 8% by mass of the above-mentioned titanium oxide-containing master pellets, and 84% by mass of the above-mentioned PET resin was used as the raw material M. Further, a mixture of 80% by mass of the amorphous polyester resin A1 and 10% by mass of atactic polystyrene resin (Nippon Polystyrene Co., Ltd., G797N; glass transition temperature 95 ° C.) and 10% by mass of the wax-containing master pellet W1. It was set as the raw material C.
The raw material M and the raw material C are vacuum-dried to a moisture content of 80 ppm, supplied to separate extruders, melted, led to a feed block, and thermally bonded from the raw material C to both surfaces of the intermediate layer (base material) made of the raw material M. After joining with a feed block so that the layers were laminated, it was extruded in the form of a film on a cooling drum adjusted to 20 ° C. from a T-shaped die to produce a three-layer unstretched film having a thickness of 2.4 mm. During the production of the unstretched film, the opposite surface of the cooling drum was cooled by blowing cold air adjusted to 20 ° C.
The obtained unstretched film is heated uniformly to 70 ° C. using a heating roll, and further heated using an infrared heater so that the film temperature becomes 95 ° C., while utilizing the speed difference between the rolls. The film was stretched 3.4 times in the direction. On the surface of the longitudinally uniaxially stretched film thus obtained, urethane resin 1 (manufactured by Dainippon Ink & Chemicals, HW-345; softening temperature 95 ° C., non-volatile content 25%, viscosity 14 mPa · s) was applied at a wet coating amount of 20 g / the coating is m ^2, and dried for 30 seconds at 80 ° C.. After coating, both ends of the longitudinally uniaxially stretched film were gripped with clips, preheated with hot air so that the film surface temperature was about 100 ° C., and then stretched 3.8 times in the lateral direction while heating to about 140 ° C. Thereafter, with the film width fixed, it was heated to about 230 ° C. with dry hot air to perform heat setting, and a 5% relaxation heat treatment was performed in the width direction while cooling to about 200 ° C. Thereafter, the film was gradually cooled, and the film edge was cut at 45 ° C. at which the surface temperature of the film was sufficiently lower than the glass transition temperature of the thermal adhesive layer, and then the film was wound into a roll.
By the above method, a heat-adhesive polyester film having a thickness of 200 μm was obtained. When the cross section of the film was observed with a scanning electron microscope, the thickness of each layer (thermal adhesive layer Aa / intermediate layer (base material) / thermal adhesive layer Ab) was approximately 20/160/20 (unit: μm). It was.

[Manufacture of flexible printed wiring boards]
FPC was produced by the following method using the heat-adhesive biaxially stretched polyester film obtained above.
First, the roll of the film obtained above was slit to obtain a roll of web-like film having a width of 400 mm and a winding length of 100 m. An aluminum foil (1N30-O, thickness 20 μm) having the same width was laminated on one side of this film while being unwound from a roll, and was subjected to heat lamination adhesion.
A schematic diagram of the laminate bonding process used here is shown in FIG.
The web-like heat-adhesive biaxially stretched polyester film unwound from the roll is guided to a preheating roll heated to a surface temperature of 100 ° C. through a guide roll at a speed of 10 m / min, and preheated while adjusting the tension to 20 N / m. did. On the other hand, the aluminum foil was unwound while adjusting the tension to 50 N / m through a guide roll, and the above heat-adhesive polyester film was laminated with a laminate roll heated to 160 ° C. and laminated. After being laminated, the web-like laminate was subjected to heat radiation in the air and cooled with a cooling roll having a surface temperature of 20 ° C., cooled to a surface temperature of 40 ° C., and then wound into a roll through a guide roll.
Next, the aluminum foil on the surface of the laminate was etched to form an antenna circuit.
First, a circuit pattern was continuously printed on the surface of the aluminum foil using an ultraviolet curable etching resist ink (ER225N, manufactured by Toyobo Co., Ltd.), and the ink was cured by irradiation with ultraviolet rays (500 mJ / cm ² ). After developing the resist with an aqueous sodium carbonate solution (1% by mass), the resist layer is etched with an aqueous ferric chloride solution (39% by mass) to which hydrochloric acid has been added and washed with an aqueous sodium hydroxide solution (3% by mass). Was removed. This was washed with water and then continuously dried at 140 ° C. to obtain FPC.

[Manufacture of inlet sheets and RFID media]
An inlet sheet was manufactured using the FPC obtained above. That is, for the web-like FPC continuum unwound from the roll, a jumper circuit is used by using insulating ink (Toyobo Co., Ltd., SR610C) and conductive ink (Toyobo Co., Ltd., DW545) at the position where the IC is to be mounted. Printed. Using this conductive ink as an adhesive, an IC chip for RFID (based on ISO15693, 13.56 MHz) was fixed on the FPC. This was wound up in a roll shape to obtain an inlet sheet for RFID media.
Next, RFID media was manufactured by the heat laminating process using the inlet sheet obtained above. A schematic diagram of the manufacturing process is shown in FIG. The web-like inlet sheet unwound from the roll was guided to a preheating roll heated to a surface temperature of 120 ° C. through a guide roll at a speed of 10 m / min, and preheated while adjusting the tension to 30 N / m. On the other hand, a web-like fine void-containing polyester film (manufactured by Toyobo Co., Ltd., Chrispar K2323, 250 μm) was unwound while adjusting the tension to 30 N / m through a guide roll, and preheated with a preheating roll in the same manner as described above. These films were laminated on both sides of the heat inlet sheet with a laminating roll heated to 160 ° C. and laminated. After being laminated, the web-like RFID media was radiated in the air and cooled with a cooling roll having a surface temperature of 20 ° C., cooled to a surface temperature of 40 ° C., and then wound as an RFID media product roll through a guide roll. The product roll of the obtained RFID media was punched by a conventional method to obtain an RFID media (IC card) of 86 mm × 54 mm.

(Example 2)
A mixture comprising 30% by mass of the above titanium oxide-containing master pellets, 35% by mass of the above PET resin, and 35% by mass of the amorphous polyester resin A1 was used as the raw material M. A mixture of 85% by mass of the above amorphous polyester resin A2 and 15% by mass of a linear low density polyethylene resin (Ube Maruzen polyethylene, Umerit 2040F; melting point 116 ° C.) as a wax was used as a raw material C. Further, the thickness of each layer to be co-extruded when an unstretched film is produced is changed to a thickness of 250 μm, that is, the thickness of each layer of thermal adhesive layer Aa / intermediate layer / thermal adhesive layer Ab is 12/26/12 (unit : Μm). Further, after longitudinal uniaxial stretching, a polyolefin resin (manufactured by Chuo Rika Kogyo Co., Ltd., AC3100; softening temperature 90 ° C., non-volatile content 45%) was applied and dried at 80 ° C. for 30 seconds. Others were carried out similarly to Example 1, and produced the heat bondable biaxially stretched polyester film.
Moreover, the surface of the metal foil laminated body obtained in the same manner as in Example 1 was subjected to resist treatment and etching treatment to produce 10 double stripe patterns having a width of 0.5 mm and an interval of 0.4 mm. The same heat-adhesive biaxially stretched polyester film as that used for the substrate was laminated on the metal foil laminate formed with this circuit using the laminating process of FIG.
That is, a web-shaped metal foil laminate (one form of FPC) unwound from a roll was introduced into a heating furnace and preheated to a surface temperature of 100 ° C. by heating with hot air. Moreover, the film was laminated | stacked on the circuit side surface of this metal foil laminated body. Other than this, film lamination was performed in the same manner as in Example 1, and a flexible flat cable (one form of FPC) in which a circuit portion was slit to a width of 10 mm and a polyester film was disposed on both sides of the circuit was produced.

(Example 3)
A mixture composed of 6% by mass of the above-mentioned cavity forming agent-containing master pellets and 94% by mass of the above PET resin was used as a raw material M. A mixture of 87% by mass of the amorphous polyester resin A2 and 3% by mass of a copolymerized polypropylene resin (manufactured by Prime Polymer Co., Ltd., melting point 138 ° C.) and 10% by mass of the wax-containing master pellet W2 was used as a raw material C. Further, the thickness of each layer to be co-extruded when an unstretched film is produced is changed to a thickness of 125 μm, that is, the thickness of each layer of thermal adhesive layer Aa / intermediate layer / thermal adhesive layer Ab is 10/100/15 (unit : Μm). Further, after longitudinal uniaxial stretching, urethane resin 2 (manufactured by Mitsui Chemicals Polyurethanes, W-6010; softening temperature 90 ° C., non-volatile content 30%) was applied and dried at 80 ° C. for 30 seconds. Others were carried out similarly to Example 1, and produced the heat bondable biaxially stretched polyester film.
Using the film obtained here, an FPC was produced in the same manner as in Example 1. However, instead of the aluminum foil, a copper foil (CU-JIS C 6515-E2-S-2 standard product, 35 μm) was used as the metal foil, and a circuit was provided on the film surface on the thermal adhesive layer Ab layer side. Moreover, the inlet sheet for RFID media was produced like Example 1 using FPC obtained here.

  Next, RFID media was manufactured by the heat laminating process using the inlet sheet obtained above. A schematic diagram of the manufacturing process is shown in FIG. The web-like inlet sheet unwound from the roll is guided at a speed of 10 m / min between an infrared heater heated to a surface temperature of 300 ° C. through a guide roll, and the surface temperature is set to 100 ° C. while adjusting the tension to 30 N / m. Preheated. On the other hand, a web-like fine void-containing polyester film (Toyobo Co., Ltd., Crisper K2323, 50 μm) was unwound while adjusting the tension to 10 N / m through a guide roll, and the above heat inlet with a laminate roll heated to 160 ° C. Laminated on both sides of the sheet and laminated. After being laminated, the web-like RFID media was radiated in the air and cooled with a cooling roll having a surface temperature of 20 ° C., cooled to a surface temperature of 40 ° C., and then wound as an RFID media product roll through a guide roll. An RFID medium (IC tag) having a size of 120 mm × 54 mm was obtained by performing a punching process after applying an adhesive process to one surface of the RFID medium.

Example 4
A mixture consisting of 15% by mass of the above-mentioned cavity forming agent-containing master pellets and 85% by mass of the above-mentioned PET resin was used as a raw material M. A mixture of 88% by mass of the above amorphous polyester resin A3, 6% by mass of cyclic polyolefin resin (Mitsui Chemicals, APL8008T, glass transition temperature 70 ° C.), and 6% by mass of wax-containing master pellets W1 is used as a raw material C. It was. Further, the thickness of each layer to be co-extruded when an unstretched film is produced is changed to a thickness of 125 μm, that is, the thickness of each layer of the thermal adhesive layer Aa / intermediate layer / thermal adhesive layer Ab is 15/220/15 (unit : Μm). Others were carried out similarly to Example 1, and produced the heat bondable biaxially stretched polyester film.
Next, after a copper foil was laminated on one side of the film obtained above in the same manner as in Example 3 to produce a metal foil laminate, resist treatment and etching treatment were performed in the same manner as in Example 2. Further, the surface of the metal foil laminate on which the circuit was formed was tin-plated to produce a flexible flat cable (one form of FPC).

(Example 5)
Only the above PET resin was used as the raw material M. Further, a mixture of 70% by mass of the amorphous polyester resin A1 and 5% by mass of the atactic polystyrene resin, 5% by mass of the linear low density polyethylene resin, and 20% by mass of the wax-containing master pellets W1 is used as the raw material C. did. Further, the thickness of each layer to be co-extruded when an unstretched film is produced is changed to a thickness of 80 μm, that is, the thickness of each layer of thermal adhesive layer Aa / intermediate layer / thermal adhesive layer Ab is 20/40/20 (unit : Μm). Others were carried out similarly to Example 1, and produced the heat bondable biaxially stretched polyester film. Others were the same as in Example 1, and FPC, inlet sheet, and RFID media (IC card) were produced.

(Example 6)
A mixture consisting of 92% by mass of the above polyethylene naphthalate resin (PEN resin) and 8% by mass of the above-mentioned cavity forming agent-containing master pellets was used as a raw material M. A mixture of 80% by mass of the amorphous polyester resin A2 and 10% by mass of the atactic polystyrene resin and 10% by mass of the wax-containing master pellet W1 was used as the raw material C.
The raw material M and the raw material C are vacuum-dried to a moisture content of 80 ppm, supplied to different extruders, melted, led to a feed block, and heat generated from the raw material C on both surfaces of the intermediate layer (base material) made of the raw material M. After joining with a feed block so that an adhesive layer was laminated | stacked, it extruded on the cooling drum adjusted to 20 degreeC from the T type | mold die, and the unstretched film of a 2.4 layer thickness 3 layer structure was manufactured. During the production of the unstretched film, the opposite surface of the cooling drum was cooled by blowing cold air adjusted to 20 ° C.
The obtained unstretched film is heated uniformly to 100 ° C. using a heating roll, and further heated using an infrared heater so that the film temperature becomes 120 ° C., while utilizing the speed difference between the rolls. Stretched 3.0 times in the direction. The urethane resin 1 was applied to the surface of the longitudinally uniaxially stretched film thus obtained and dried at 80 ° C. for 30 seconds. After coating, both ends of the longitudinally uniaxially stretched film were gripped with clips, preheated with hot air so that the film surface temperature was about 140 ° C., and then stretched 3.4 times in the lateral direction while heating to about 170 ° C. Thereafter, with the film width fixed, the film was heated to about 240 ° C. with hot dry air and heat fixed, and then 5% relaxation heat treatment was performed in the width direction while cooling to about 200 ° C. Thereafter, the film was gradually cooled, and after the surface temperature of the film became sufficiently lower than the glass transition temperature of the heat-adhesive layer, the end of the film was cut out, and then the film was wound into a roll.
Thereby, a heat-adhesive polyester film having a thickness of 200 μm was obtained. When the cross section of the film was observed with a scanning electron microscope, the thickness of each layer (thermal adhesive layer Aa / intermediate layer (base material) / thermal adhesive layer Ab) was approximately 20/160/20 (unit: μm). It was.
Using the film obtained above, an FPC, an inlet sheet, and an RFID medium (IC tag) were produced in the same manner as in Example 3.

(Comparative Example 1)
A flexible flat cable (one form of FPC) was produced in the same manner as in Example 1 except that the urethane resin 1 was not applied in the production process of the biaxially stretched polyester film.

(Comparative Example 2)
A mixture consisting of 8% by mass of the above-mentioned cavity forming agent-containing master pellets, 8% by mass of the titanium oxide-containing master pellets and 84% by mass of the above-mentioned PET resin was used as the raw material M. A mixture of 95% by mass of the amorphous polyester resin A1 and 5% by mass of the polypropylene resin was used as a raw material C, and a raw material composition containing no wax was used. In addition, urethane resin 3 (Dainippon Ink Chemical Co., Ltd., HW-950; softening temperature 180 ° C., non-volatile content 30%, viscosity 500 mPa · s) was used as the coating liquid instead of urethane resin 1. Other than this, an FPC, an inlet sheet, and an RFID medium (IC card) were produced in the same manner as in Example 1.
(Comparative Example 3)
A mixture consisting of 30% by mass of the above-mentioned titanium oxide-containing master pellets and 70% by mass of the above-mentioned PET resin was used as a raw material M. A mixture of 94% by mass of the amorphous polyester resin A2 and 6% by mass of atactic polystyrene resin was used as the raw material C. Other than this, a flexible flat cable (one form of FPC) was produced in the same manner as in Example 2.

(Comparative Example 4)
A transparent biaxially stretched polyester film containing no fine cavities (Toyobo Co., Ltd., Cosmo Shine A4300, 100 μm thick) was coated with a hot-melt adhesive (Toyobo Co., Ltd., Byron GM920) by extrusion lamination method. A biaxially stretched polyester film having an adhesive layer having a thickness (thermal adhesive layer Aa / intermediate layer (base material) / thermal adhesive layer Ab) of approximately 10/100/15 (unit: μm) was prepared.
Since this film had a large coefficient of friction and a very smooth surface, it was difficult to heat-bond the metal foil with a roll. Therefore, FPC was produced by a conventionally known heat press method. That is, after cutting the above-mentioned film into a 30 cm square, the copper foil used in Example 3 was laminated on the surface of the thermal adhesive layer Ab layer side, and the upper and lower surfaces were protected with a Teflon (registered trademark) sheet and heat-pressed (140 Bonding was performed at a temperature of 0.3 MPa for 10 minutes. About this metal foil laminated body, the resist process and etching process similar to Example 1 were performed in the batch process, and FPC was produced.

  Next, an inlet sheet and an RFID medium were produced using this FPC. That is, after producing an inlet sheet in the same manner as in Example 1 for the FPC, a void-containing polyester film (Toyobo Co., Ltd., Chrispar K2323, 50 μm) was placed on both sides of the inlet sheet, and heat press (140 ° C., Bonding was performed at 0.3 MPa for 10 minutes. Other than that, RFID media (IC tag) was obtained in the same manner as in Example 3.

(Comparative Example 5)
A transparent biaxially stretched polyester film (Toyobo Co., Ltd., E5000, thickness: 250 μm) not containing fine cavities and the above aluminum foil were laminated while being unwound from a roll, and subjected to heat lamination adhesion. That is, the web-like transparent biaxially stretched polyester film unwound from the roll is guided to a hot air oven heated to a temperature of 180 ° C. through a guide roll at a speed of 10 m / min. Was preheated while adjusting to 5 N / m. On the other hand, the aluminum foil was unwound while adjusting the tension to 10 N / m through a guide roll, and the biaxially stretched polyester film was laminated with a laminate roll made of Teflon (registered trademark) heated to 290 ° C. and laminated. After being laminated, the web-like laminate is subjected to heat radiation in the air and cooled with a Teflon (registered trademark) cooling roll having a surface temperature of 60 ° C., and then cooled to a surface temperature of 40 ° C. and then rolled into a roll through a guide roll. Winded up.
About the obtained metal foil laminated body, the resist process similar to Example 4, the etching process, and the tin plating process were performed, and the flexible flat cable (one form of FPC) was produced.

(Comparative Example 6)
A mixture consisting of 10% by mass of the titanium oxide-containing master pellets and 90% by mass of the amorphous polyester resin A was used as a raw material M. The raw material M was vacuum-dried to a moisture content of 80 ppm and supplied to one extruder. This raw material was heated to 280 ° C. inside the extruder and melt-mixed, then extruded onto a cooling drum adjusted to 20 ° C. from a T-shaped die, and an unstretched amorphous white polyester resin sheet (thickness 0.3 mm) Manufactured. The opposite surface of the cooling drum was cooled by blowing cold air adjusted to 20 ° C. and relative humidity 30%.
Since the obtained sheet had insufficient heat resistance, sufficient tension could not be applied during heating, and it was difficult to heat laminate a metal foil with a roll. Therefore, as in Comparative Example 3, FPC, an inlet sheet, and RFID media (IC tag) were produced in a batch process by a conventionally known heat press method.

(Comparative Example 7)
After applying an epoxy-containing polyester polyurethane adhesive to a thickness of 3 g / m ^{2 on} one side of a cavity-containing polyester film (Toyobo Co., Ltd., Chrispar K1212, thickness 100 μm), the above aluminum foil is unwound from a roll and continuously processed. And dry laminated. Further, an FPC and an inlet sheet were produced in the same manner as in Example 1 for this metal foil laminate. Next, the inlet sheet obtained above was dry-laminated using the above adhesive to produce an RFID medium. That is, after applying an epoxy-containing polyester polyurethane adhesive to a circuit side surface of a web-like inlet sheet unwound from a roll to a thickness of 3 g / m ² , a web-like fine void-containing polyester film (manufactured by Toyobo Co., Ltd., (Crisper K2323, 250 μm) was dry laminated and unwound from a roll to produce an RFID medium (IC card).

Table 1 shows the structures and properties of the heat-adhesive biaxially stretched polyester films obtained in Examples and Comparative Examples, and Table 2 shows the properties of FPC and RFID media obtained using the films.
The FPC and RFID media obtained in Examples 1 to 6 had a small defect rate and a small variation in communication distance, and were excellent in appearance and heat resistance of the product. Moreover, continuous processing was possible as a web-like film, and the productivity was excellent.
On the other hand, in Comparative Example 1, although the film and the metal foil were bonded to each other, the peel strength was insufficient, and thus the FPC characteristics needed to be improved. Moreover, in Comparative Example 2, since the adhesion start temperature of the coating layer was high and the coating layer was not sufficiently softened, there was a problem in terms of peel strength. Furthermore, in Comparative Examples 2 and 3, since the slipperiness between the film and the metal foil was not sufficient, fine wrinkles were produced during the metal foil lamination, causing a problem in the appearance of the product. In addition, due to this, there is a disadvantage that the defect rate is high and the communication distance varies greatly. Further, in Comparative Example 4, since the slipperiness was poor, the product was not able to be manufactured by continuous lamination due to significant wrinkles and bubbles, and the adhesion by the heat press method was forced. For this reason, the production rate was low and the defect rate increased. Further, the variation in the communication distance was increased due to the uneven thickness of the hot melt adhesive layer. In Comparative Example 5, in the laminating process after forming the circuit, the film was thermally deformed and lost its flatness, resulting in poor appearance such as curling and wrinkling on the FPC. This is because the film layer was melted when the metal foil laminate was produced by heat lamination adhesion, and the base material layer became an amorphous polyester sheet having substantially no orientation. In Comparative Example 6, since the base material layer is an amorphous polyester sheet having substantially no orientation, it is difficult to heat and heat laminate in a state where tension is applied. Could not be manufactured. In the adhesion by the heat press method, the production rate is low and the defect rate cannot be reduced. Although the production process of Comparative Example 7 did not cause any significant problems, dry lamination using a solvent was required twice, and this is a method that should be improved in terms of environmental suitability and complexity of the work process. In addition, since the thickness of the adhesive layer is not sufficient, the unevenness absorbability of the integrated circuit and the antenna circuit is not sufficient, resulting in a need for improvement in the variation of the appearance of the product and the communication distance.

  Abbreviations in the table are as follows. PS: atactic polystyrene resin, PP: polypropylene resin, LLDPE: linear low density polyethylene resin, COC: cyclic polyolefin resin, PE: polyethylene wax, PEG: polyethylene glycol, Al: aluminum foil, Cu: copper foil.

  In the FPC of the present invention, a heat-adhesive layer having good slipperiness is provided on a heat-resistant base material by coextrusion, and a web-like film and a metal foil are heat-bonded in a continuous laminating process to produce an FPC. Is possible. Therefore, not only a high production rate can be obtained, but also RFID media can be produced at a high production rate by a continuous laminating process. In addition, the production of RFID media by the continuous laminating process can improve the defective product occurrence rate and improve the electrical quality variation as compared with the conventional press process using an adhesive. Therefore, the present invention greatly contributes to the social spread of RFID media.

It is a schematic diagram of the lamination adhesion process used in Examples 1, 2, and 5. 3 is a schematic diagram of a laminate bonding process used in Examples 1, 3, 4, 5, and 6. FIG. 6 is a schematic diagram of a laminate bonding process used in Example 2. FIG. It is a schematic diagram of the laminate adhesion process used in Examples 3 and 6.

Explanation of symbols

1: Roll of unrolled film or inlet sheet, metal foil laminate 2: Guide roll 3: Roll of unrolled metal foil or inlet sheet, film 4: Preheating roll 5: Laminating roll 6: Cooling roll 7: Nip roll 8: Product roll of wound FPC or RFID media 9: Heating furnace 10: Infrared heater

Claims (11)

  Biaxially stretched polyester film in which a base layer is formed with a thermal adhesive layer formed by coextrusion and a coating layer formed by coating on the surface of the thermal adhesive layer, and a metal foil adhered to the coated layer surface of the biaxially stretched polyester film A flexible printed wiring board comprising: a base layer of a biaxially stretched polyester film having a melting point at 200 to 300 ° C., and a thermal adhesive layer comprising a polyester resin containing wax. Board.   2. The flexible printed wiring board according to claim 1, wherein the base material layer of the biaxially stretched polyester film is a white polyester film containing a white pigment or fine cavities therein.   The flexible printed wiring board according to claim 1, wherein the thermal adhesive layer is made of a mixture of an amorphous polyester resin A, a thermoplastic resin B incompatible with the amorphous polyester resin A, and a wax. The flexible printed wiring board according to claim 3, wherein the thermal adhesive layer has all the following features (1) to (4).
(1) The glass transition temperature of the amorphous polyester resin A is 50 to 95 ° C.
(2) The thermoplastic resin B is any of a crystalline resin having a melting point of 50 to 180 ° C., an amorphous resin having a glass transition temperature of −50 to 150 ° C., and a mixture thereof.
(3) 1-30 mass% of thermoplastic resin B is contained in the thermal adhesive layer.
(4) The thickness of the heat bonding layer is 5 to 30 μm.   The coating layer is formed by applying a coating solution made of a resin having an adhesion start temperature of 160 ° C. or lower to one side of a polyester film that has been uniaxially stretched, and further stretching in a direction perpendicular to the uniaxial stretching direction after coating. The flexible printed wiring board according to claim 1, wherein:   The flexible printed wiring board which adhere | attached and laminated | stacked another resin film on the coating layer surface or heat bonding layer surface exposed by etching the metal foil of the flexible printed wiring board in any one of Claims 1-5.   An inlet sheet for RFID media, in which an integrated circuit is arranged on the flexible printed wiring board according to claim 1.   An RFID medium configured using the inlet sheet according to claim 7.   Polyester containing a wax formed by coextrusion as a web-like film in a method for producing a flexible printed wiring board having a step of continuously laminating a web-like film wound up in a roll shape and a metal foil while unwinding A flexible printed wiring board using a biaxially stretched polyester film in which a thermal adhesive layer made of a resin and a coating layer formed by coating on the surface of the thermal adhesive layer is formed on a base material layer having a melting point at 200 to 280 ° C. Manufacturing method.   In the manufacturing method of RFID media which has the process of carrying out the continuous heat lamination, unwinding the several web-like film wound up by roll shape, and the flexible printed wiring board or the inlet sheet, The flexible printed wiring of Claims 1-7 A method for manufacturing RFID media, comprising using a plate or an inlet sheet.   The RFID circuit manufacturing method according to claim 9, wherein the antenna circuit is arranged on the surface of the flexible printed wiring board or the inlet sheet of the biaxially stretched polyester film applied to the flexible printed wiring board according to claim 1.

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