JP2019214173A - Functional film, molded body, and manufacturing method therefor - Google Patents

Abstract

To provide a functional film having a decorative layer and an electric circuit layer, and high in followability to a curved surface shape, a molded body having the same, and a manufacturing method therefor.SOLUTION: There are provided a functional film having a decorative layer, and an electric circuit layer on the decorative layer on a first surface side of a transparent substrate film in this order, in which the electric circuit layer includes a first electrical wiring and a second electrical wiring formed via an insulation ink, the substrate film and the electric circuit layer has flexibility, preferably an uneven structure for light scattering is formed in a part of the first surface side, and a light source is equipped at a terminal of the substrate film, a molded body having the same and a manufacturing method therefor.SELECTED DRAWING: Figure 3

Description

  The present invention relates to a functional film, a molded article, and a method for producing the same, which are suitably used for electronic devices and the like.

  A film (decoration part) is formed on the surface of the housing of an electronic device to be incorporated into an interior part of a vehicle such as an automobile, a portable device, a home appliance, an office product, an interior material for a building, etc. in order to impart designability. A resin molded product incorporating a decorative film) may be used.

  On the other hand, in recent years, as a function of an electronic device, a touch sensor capable of inputting a command to the device by touching a finger is generally used in recent years. Also in the above-mentioned housing, with the miniaturization and sophistication of electronic devices and changes in design, it is required to provide an electronic function to a curved surface shape. The need to provide circuits is emerging.

  Further, the operation display unit of the electronic device includes an illuminated key capable of operating the device even at night or in a dark place, or a display having a backlight or a self-luminous display. In recent years, as a switch structure of an illuminated key of a thinned mobile phone, a type in which an LED is illuminated from the side of an operation surface with an LED light source has been developed for thinning. Even when an illuminated key or a display is provided, it is required to follow a curved surface shape as described above.

  In Patent Literature 1, a decorative film, a touch sensor film, and a light guide plate used for a surface light source are laminated, a transparent resin serving as a housing is simultaneously formed by insert molding, and a side light is arranged on a side surface of the light guide plate. Thus, a technique for obtaining a molded body having a touch sensor function and an illumination function has been disclosed. However, since the decorative film, the touch sensor film, and the light guide plate are bonded together via the adhesive layer, the total film thickness becomes large, and the ability to follow a curved surface shape is insufficient.

JP 2008-210528 A

  The present invention has been made to solve the above problems, and an object of the present invention is to provide a functional film having a decorative layer and an electric circuit layer, and having high followability to a curved surface shape, and a molded article having the same. , As well as methods for their manufacture.

In order to solve the above-mentioned problem, the functional film of the present invention is provided on the first surface side of the transparent base film,
A decorative layer,
And an electric circuit layer on the decorative layer in this order,
The electric circuit layer includes a first electric wiring and a second electric wiring formed via an insulating ink layer,
The base film and the electric circuit layer have elasticity.

Further, the functional film of the present invention is characterized in that a concave / convex structure for light scattering is formed on a part of the base film on the first surface side.

  The functional film of the present invention is characterized in that a first low refractive index layer having a smaller refractive index than the base film is provided between the base film and the decorative layer.

  The functional film of the present invention is characterized in that a light source is provided at an end of the base film.

  The functional film of the present invention is characterized in that the electric circuit layer includes an operation circuit of the light source.

  The functional film of the present invention is characterized in that the first electric wiring and the second electric wiring include a touch sensor electric wiring that intersects in a grid in a plan view.

  The functional film of the present invention is characterized in that a second low refractive index layer having a smaller refractive index than the base film is provided on the second surface side of the transparent base film.

Further, the functional film of the present invention, on the first surface side of the transparent base film,
A first low refractive index layer having a smaller refractive index than the base film,
An electric circuit layer on the first low refractive index layer, in this order,
The electric circuit layer includes a first electric wiring and a second electric wiring formed via an insulating ink layer,
The base film and the electric circuit layer have elasticity,
An uneven structure for light scattering is formed on a part of the first surface side of the base film,
With a light source at the end of the base film,
On the second surface side of the transparent base film, a second low refractive index layer,
And a decorative layer on the second low refractive index layer in this order.

The method for producing a functional film of the present invention includes a step of forming the uneven structure on the base film by extrusion.
Forming at least one of the first low refractive index layer and the second refractive index layer;
A step of forming the decorative layer;
Forming the electric circuit layer by a printing method.

  The molded article of the present invention is characterized in that any one of the functional films described above and a housing are laminated.

The manufacturing method of the molded article of the present invention, any one of the functional film is placed between a pair of injection molding dies, the mold is closed,
After injecting the molten resin into the cavity formed by the pair of injection molding dies and onto the surface of the functional film on which the electric circuit layer is formed, the pair of injection molding dies is molded. The functional film and the housing are laminated at the same time that the housing is formed by opening the housing.

  According to the functional film of the present invention, and a molded article including the same, and the method for producing the same, the functional film includes a decorative layer and an electric circuit layer, so that a single base film has a design property and an electronic property. Functions can be consolidated, and the total film thickness decreases. Further, since the base film and the electric circuit layer have elasticity, a functional film having a high followability to a curved surface shape, a molded article provided with the functional film, and a method for producing the same can be obtained. Further, since a laminating step is unnecessary in the production of the functional film, the cost can be reduced by simplifying the process and reducing the number of materials.

1 is a schematic cross-sectional view according to a first embodiment of a functional film of the present invention. FIG. 4 is a schematic cross-sectional view according to a second embodiment of the functional film of the present invention. It is a schematic cross section concerning a 3rd embodiment of a functional film of the present invention. It is a schematic cross section concerning a 4th embodiment of a functional film of the present invention. It is a schematic sectional view concerning a 5th embodiment of a functional film of the present invention. According to the fifth embodiment of the functional film of the present invention, (a) a schematic cross-sectional view in which a light emitting portion is partially enlarged, and (b) a calculation example of transmittance with respect to the thickness of the second low refractive index layer. It is a characteristic diagram. It is a schematic sectional view concerning a 6th embodiment of a functional film of the present invention. FIG. 6 is a schematic cross-sectional view illustrating a molded body having a functional film according to a third embodiment of the invention, according to an embodiment of the molded body of the invention.

  Hereinafter, a functional film, a molded article, and a method for manufacturing the same according to an embodiment of the present invention will be described with reference to the drawings. The same components are denoted by the same reference numerals unless there is a reason for convenience, and duplicate description will be omitted. In each drawing, the thickness and ratio of components may be exaggerated for the sake of clarity, and the number of components may be reduced in the drawings. Further, the present invention is not limited to the following embodiments without departing from the gist thereof.

[First Embodiment]
FIG. 1 is a schematic cross-sectional view according to a first embodiment of the functional film of the present invention. The functional film 10 of the first embodiment includes a decorative layer 3a on the first surface side of the transparent base film 1, and an electric circuit layer 4 on the decorative layer 3a in this order, The electric circuit layer 4 includes a first electric wiring 4-1 and a second electric wiring 4-2 formed via the insulating ink layer 4a, and the base film 1 and the electric circuit layer 4 expand and contract. Has the property.

  The decorative layer 3a is translucent or light-shielding, has a light transmitting portion or a light semi-transmitting portion (hereinafter, referred to as a light transmitting portion) 3T, and has a pattern such as a character or a figure formed thereon. Is also good. Therefore, when integrated with the external light 11 or the lighting device or the display, the light 11 is incident, and the light transmitting portion 3T of the base film 1 is visually recognized, resulting in a design.

  The base film 1 having elasticity is made of a highly transparent material that efficiently transmits visible light so that the decorative layer 3a can be visually recognized. Acrylics such as polyethylene terephthalate (PET) and polymethyl methacrylate (PMMA), polycarbonate (PC), silicone rubber (PDMS), polyurethane, polypropylene, etc. are preferred, especially for small sizes such as PMMA and smartphones with low light absorption. PC is suitable.

  The decorative layer 3a is made of a colored ink containing a pigment or dye of an appropriate color as a colorant, or a multilayer film capable of exhibiting a structural color. It is particularly preferable to use a coloring ink from the viewpoint of cost. As a method for forming the decorative layer 3a using the coloring ink, a normal printing method such as an offset printing method, a gravure printing method, or a screen printing method can be used. This makes it possible to easily form a picture having the light transmitting portion 3T. As the binder resin, a polyvinyl chloride resin, a polyamide resin, a polyester resin, a polyacrylic resin, a polyurethane resin, a polyvinyl acetal resin, a polyester urethane resin, a cellulose ester resin, an alkyd resin, or the like may be used. .

The electric circuit layer 4 having elasticity is preferably formed by a printing method or an inkjet method. That is, a step of forming and drying the first electric wiring 4-1 using the conductive paste, and a step of applying and drying the insulating ink layer 4a so as to cover the pattern of the first electric wiring 4-1. Forming a pattern of the second electric wiring 4-2 using a conductive paste on the insulating ink layer 4a, and forming the pattern of the first electric wiring 4-1, the insulating ink layer 4a, and the second electric wiring. The electric circuit layer 4 having elasticity can be formed by heat-treating at least two layers of the pattern of 4-2 collectively to form a laminate.

  The electric circuit layer 4 can be, for example, an electric wiring for a touch sensor as described later, and includes a first electric wiring 4-1 and a second electric wiring 4 formed via an insulating ink layer 4a. 2 to form an operating circuit of a light source, an operating circuit of a communication antenna, or the like. When the electronic function is specified, a single-layer electric wiring layer may be used, in which case the followability to the curved surface shape is further improved.

  Examples of the conductive material contained in the conductive paste include Ag (silver), Ag nanowire, Ag flake, Cu (copper), PEDOT (poly (3,4-ethylenedioxythiophene)), carbon, carbon nanotube, Graphene and the like. Examples of the binder resin used for the conductive polymer include an acrylic resin, a polyester resin, a polyurethane resin, a polyamide resin, and a polyurea resin. Alternatively, the first electric wiring 4-1 and the second electric wiring 4-2 may be formed using a commercially available conductive polymer. The conductive material used for the first electric wiring 4-1 and the second electric wiring 4-2 may be different.

  As the insulating ink that forms the insulating ink layer 4a, an ink whose main constituent solvent is an organic solvent is used. As the organic solvent, one that dissolves an insulating material is used, and examples thereof include cyclohexanone, toluene, N-methyl-2-pyrrolidone, propylene glycol monomethyl ether acetate, and isopropyl alcohol.

  Examples of the insulating material include acrylic resins such as polyvinyl phenol, polyparaxylene, polyimide, polyacrylonitrile, and polymethyl methacrylate; epoxy resins; and resins such as cyanoethyl pullulan. Among these insulating materials, those having resistance to an aromatic solvent after drying the insulating ink layer 4a, or those capable of obtaining resistance to an aromatic solvent by thermal curing or light curing after drying are preferable.

[Second Embodiment]
FIG. 2 is a schematic cross-sectional view according to a second embodiment of the functional film of the present invention. The functional film 20 according to the second embodiment has, in addition to the structure of the functional film 10 according to the first embodiment, unevenness for light scattering on a part of the first surface of the base film 1. The structure 5a is formed. The shape of the concavo-convex structure 5a is not particularly limited, but is preferably left-right symmetric. Therefore, the external light 11 entering the base film 1 through the light transmitting portion 3T or the translucent decorative layer 3a or the light 11 from the display is scattered by the uneven structure 5a. The emitted light has an increased oblique component and is visually recognized as a design part with more glitter than in the first embodiment.

[Third Embodiment]
FIG. 3 is a schematic cross-sectional view according to a third embodiment of the functional film of the present invention. The functional film 30 according to the third embodiment has a first low refractive index layer 2 having a lower refractive index than the base film between the base film 1 and the decorative layer 3b. A light source 31 is provided at one end, and an uneven structure 5 b is formed on the base film 1. By providing the light source 31, a design effect in darkness can be provided. The light emitted from the light source 31 emits air (refractive index) on the interface between the base film 1 and the first low refractive index layer 2 having a smaller refractive index than that of the base film 1 using the base film 1 as a light guide plate. = 1.0), and travels in the horizontal direction as shown by the ray trajectory (shown schematically with one ray) while repeating reflection at the interface with (= 1.0). Here, the electric circuit layer 4 can be an operation circuit of the light source 31 or an electric wiring layer connected to the operation circuit.

  Since the refractive index of the base film 1 is usually 1.5 or more, the first low refractive index layer 2 preferably has a refractive index of 1.45 or less in order to increase the interface reflectance. A low refractive index resin such as a resin or a silicon resin is used. Alternatively, as described in Japanese Patent No. 6244928, a composition in which inorganic fine particles are mixed with a binder resin such as an acrylic resin, a polyester resin, a polyurethane resin, a polyamide resin, and a polyurea resin is applied, and ultraviolet irradiation or heating is performed. By curing, a low refractive index layer can be obtained.

  Since the decorative layer 3b is located above the optical path of the light from the light source 31 disposed on the side surface of the base film (on the first surface side), no light transmitting portion is required. As the material and the forming method of the decorative layer 3b, the same material as the decorative layer 3a of the first and second embodiments can be used.

  Since the uneven structure 5b is formed on the base film 1, light traveling in the lateral direction and reflected at the interface between the base film 1 and the first low refractive index layer 2 is scattered by the uneven structure 5b. The shape of the concavo-convex structure 5b is not particularly limited, but is preferably a left-right asymmetric shape so that the scattered light has many vertical components toward the second surface and exits. Thereby, the portion where the uneven structure 5b is formed is visually recognized as a design portion. Although FIG. 3 shows only one uneven structure 5b, a plurality of uneven structures 5b may exist.

  As the light source 31, for example, a light emitting diode (LED) or a thin film type electroluminescence (thin film type EL) can be used. The light source 31 is provided on at least a part of the entire periphery of the base film 1. For example, a plurality of light sources may be provided side by side along the periphery of one side. As the LED, for example, a white LED is preferable, but a blue LED or a red LED may be used. In addition, a plurality of types of LEDs may be used, and for example, white light may be obtained from LEDs of three colors of R, G, and B.

[Fourth Embodiment]
FIG. 4 is a schematic cross-sectional view according to a fourth embodiment of the functional film of the present invention. The functional film 40 of the fourth embodiment is different from the functional film 30 of the third embodiment in that the uneven structure 5b of the base film 1 exists in a region included in the electric circuit layer 4 in a plan view. By touching the spot where the scattered light due to the concavo-convex structure 5b is visually recognized, the first electric wiring 4-1 and the second electric wiring 4-2 of the electric circuit layer 4 intersect in a lattice shape in a plan view. It can function as a touch sensor electrical wiring. The first electric wiring 4-1 and the second electric wiring 4-2 are connected to a touch position detecting circuit. Although only one uneven structure 5b is shown in FIG. 4, a plurality of uneven structures 5b can be formed to provide a plurality of electronic functions. Note that the grid-like intersection is not limited to orthogonal, and may cross diagonally.

[Fifth Embodiment]
FIG. 5 is a schematic cross-sectional view according to a fifth embodiment of the functional film of the present invention. The functional film 50 according to the fifth embodiment has the structure of the functional film 30 (FIG. 3) according to the third embodiment, and is more refracted on the second surface side of the base film 1 than the base film. A second low refractive index layer 6 having a small refractive index is provided.

  The second low-refractive-index layer 6 has a higher refractive index than the air (refractive index = 1.0) on the second surface side. The reflection at the interface with the material film 1 can be maintained equivalent to that of air. As the material of the second low refractive index layer 6, the same material as that of the first low refractive index layer can be used.

  The second low-refractive-index layer 6 changes the transmittance emitted to the second surface side according to the scattering direction of the scattered light (= the incident direction to the second low-refractive-index layer 6). FIG. 6 relates to the functional film 50 of the fifth embodiment, and (a) is a schematic cross-sectional view in which a light emitting portion is partially enlarged, and (b) calculates the transmittance with respect to the thickness of the second low refractive index layer 6. FIG. 6 is a characteristic diagram showing an example of the operation. Here, the calculation was performed on the assumption that the wavelength was 550 nm, which is the center of the visible light region, the refractive index of the base film 1 was 1.8, and the refractive index of the second low refractive index layer 6 was 1.4.

  As can be seen from the calculation result of FIG. 6B, the transmittance periodically fluctuates with respect to the thickness of the second low refractive index layer 6 as a result of the thin film interference, but the magnitude thereof is the second low refractive index layer. The thickness at which the transmittance peaks depends on the incident angle θ to the refractive index layer 6 and also changes according to the incident angle θ. By providing the second low-refractive-index layer 6 in this way, the visibility of the design portion can be given a variety depending on the viewing direction.

[Sixth Embodiment]
FIG. 7 is a schematic cross-sectional view according to a sixth embodiment of the functional film of the present invention. When the structure of the functional film 60 of the sixth embodiment is compared with the functional film 30 of the third embodiment (FIG. 3), the decorative layer 3c is provided not on the first surface but on the second surface. Have. The decorative layer 3c may be semi-transparent or light-shielding and partially have a light transmitting portion. Therefore, the design part of the decorative layer 3c is visually recognized by the scattered light by the uneven structure 5b. When the decorative layer 3c is provided on the second surface side, it becomes easy to produce a functional film that differs only in the decorative layer. In addition, a protective layer (not shown) may be separately provided on the outer layer of the decorative layer 3c in order to suppress the risk of the decorative layer peeling off.

  Further, in the functional film 60 of the sixth embodiment, similarly to the functional film 50 of the fifth embodiment (FIG. 5), the second low refractive index layer 6 is provided immediately below the base film 1. . With the above structure, in the functional film 60 of the sixth embodiment, the visual effect in which the case of the functional film 30 of the third embodiment and the structure of the functional film 50 of the fifth embodiment are simply superimposed. Is born, and these structures can be used properly depending on the application.

[Molded body provided with functional film of the present invention]
FIG. 8 is a schematic cross-sectional view illustrating a molded article according to an embodiment of the molded article of the present invention, which is provided with the third embodiment of the functional film of the present invention. The molded body 100 of the present embodiment has a structure in which the functional film of the third embodiment of the present invention and a housing 91 are laminated.

  The molded article of the present invention is obtained by placing the functional film of any of the first to sixth embodiments between a pair of injection molding dies, closing the mold, and using the pair of injection molding dies. In the formed cavity, after injecting the molten resin on the side of the functional film on which the electric circuit layer is formed, the casing is formed by opening the pair of injection molding dies. At the same time, it is produced by laminating a functional film and a housing. The housing may be manufactured to have a shape having an opening.

  Examples of the material of the housing include general-purpose resins such as a polystyrene resin, a polyolefin resin, an ABS resin, an AS resin, and an AN resin. Uses general-purpose engineering resins such as polyphenylene oxide / polystyrene resin, polycarbonate resin, polyacetal resin, polyacrylic resin, polycarbonate-modified polyphenylene ether resin, polybutylene terephthalate resin, polybutylene terephthalate resin, and ultra-high molecular weight polyethylene resin can do.

The installation of the light source on the functional film after the third embodiment of the present invention is performed by disposing the light source on the side of the base film of the functional film before being placed between the molds in the above-described injection molding process. Alternatively, the light source may be installed in the molded article of the present invention after the mold is opened by disposing the light source on the side of the base film of the molded article taken out from the injection mold. In any case, since it is arranged on the side surface of the base film, it is not necessary to separately stack a light source mounting substrate.

  As described above, in the functional film of the present invention and the molded article provided with the same, the base film and the electric circuit layer have elasticity, and one base film has the design property and the electronic function. Since the aggregation is performed, a bonding step is not required, and a functional film having a high conformability to a curved surface shape with a reduced total film thickness, and a molded article having the same can be obtained. It should be noted that the present invention is not limited to the above embodiments as they are, and can be embodied by appropriate combinations and modifications without departing from the gist of the present invention.

  Uses of the functional film and the molded article according to the present invention are not particularly limited, and include, for example, various vehicle interior parts such as dashboards and door inner materials of automobiles, mobile devices, communication devices, home appliances, and office products. It can be suitably used for a housing of an electronic device incorporated in a product, a building interior material, a container for food or various articles, and the like.

10, 20, 30, 40, 50, 60 ... Functional film 1 of the present invention ... Base film 2 ... First low refractive index layer 3a, 3b, 3c ... Decorative layer 3T ... Light transmitting portion 4... Electric circuit layer 4-1... First electric wiring 4-2... Second electric wiring 4a... Insulating ink layers 5a and 5b. ..Concavo-convex structure 6 ... Second low refractive index layer 11 ... External light or light from a display 31 ... Light source 91 ... Case 100 ... A molded article of the present invention

Claims (10)

On the first surface side of the transparent base film,
A decorative layer,
And an electric circuit layer on the decorative layer in this order,
The electric circuit layer includes a first electric wiring and a second electric wiring formed via an insulating ink layer,
The base film and the electric circuit layer have elasticity,
Functional film characterized by the above.   The functional film according to claim 1, wherein an uneven structure for light scattering is formed on a part of the base film on the first surface side. With a light source at the end of the base film,
Between the base film and the decorative layer, a first low refractive index layer having a smaller refractive index than the base film,
The functional film according to claim 2, wherein: The electric circuit layer includes an operation circuit of the light source,
The functional film according to claim 3, wherein: The first electrical wiring and the second electrical wiring include a touch sensor electrical wiring that intersects in a grid in plan view.
The functional film according to any one of claims 1 to 4, characterized in that: On the second surface side of the transparent base film, a second low refractive index layer having a smaller refractive index than the base film,
The functional film according to any one of claims 1 to 5, characterized in that: On the first surface side of the transparent base film,
A first low refractive index layer having a smaller refractive index than the base film,
An electric circuit layer on the first low refractive index layer, in this order,
The electric circuit layer includes a first electric wiring and a second electric wiring formed via an insulating ink layer,
The base film and the electric circuit layer have elasticity,
An uneven structure for light scattering is formed on a part of the first surface side of the base film,
With a light source at the end of the base film,
On the second surface side of the base film, a second low refractive index layer,
A decorative layer on the second low refractive index layer, in this order,
Functional film characterized by the above. A step of forming the uneven structure on the base film by extrusion,
Forming at least one of the first low refractive index layer and the second refractive index layer;
A step of forming the decorative layer;
Forming the electric circuit layer by a printing method,
The method for producing a functional film according to claim 3, wherein:   A molded article comprising the functional film according to any one of claims 1 to 7 and a housing laminated. The functional film according to any one of claims 1 to 7 is placed between a pair of injection molding dies, the mold is closed,
After injecting the molten resin into the cavity formed by the pair of injection molding dies, on the side of the functional film on which the electric circuit layer is formed, the pair of injection molding dies is molded. At the same time as forming the housing by opening, laminating the functional film and the housing,
The method for producing a molded article according to claim 9, wherein: