JP7596689B2 - Molded film, molded article, and method for producing same - Google Patents

Description

The present invention relates to a molded film, a molded body, and a method for producing the same.

Patent Document 1 discloses a specific conductive circuit integrated molded product having a resin molded body, a base film embedded flush with one surface of the resin molded body, and a conductive circuit disposed between the resin molded body and the base film.
Patent Document 1 describes a method for manufacturing the conductive circuit integrated molded product, in which a base film on which a specific conductive circuit is formed is placed on the cavity surface of an injection molding die, and then molten resin is injected to injection mold a resin molded body.
In Patent Document 1, the conductive circuit is formed by etching a specific transparent metal thin film.

A printing method using conductive ink has been considered as a method for forming a conductive circuit to replace the etching method. The method of printing conductive ink does not require any complicated steps compared to the etching method, and can easily form a conductive circuit, improving productivity and reducing costs.
For example, Patent Document 2 discloses a specific conductive ink containing specific conductive fine particles and a specific epoxy resin as a low-temperature processing type conductive ink capable of forming a high-definition conductive pattern by screen printing. It is said that the screen printing makes it possible to form a thick conductive pattern and to realize a low resistance conductive pattern.

Patent Document 3 also discloses a method for manufacturing a decorative sheet capable of expressing a three-dimensional effect, in which a laminate having a printed layer printed in a pattern on a transparent resin layer and a laminate sheet having a decorative layer on a base film are thermocompression-bonded to each other, thereby giving the decorative layer an uneven shape that follows the pattern of the printed layer.

Patent document 4 also discloses a method for producing a conductive circuit integrated molded product having a conductive circuit disposed between a resin molded body and a base film by a printing method using conductive ink, and a process of thermoforming a molded film having a conductive pattern formed on a base film and integrating the molded film with a resin molded body.

JP 2012-11691 A JP 2011-252140 A JP 2007-296848 A JP 2019-189680 A

According to the method of Patent Document 1, a conductor can be easily provided on the surface of a molded body. On the other hand, there is an increasing demand for forming a conductive circuit on the surface of a substrate having various shapes, such as a substrate having an uneven surface or a curved surface. When a conductive circuit is formed by laminating a film having a conductive layer on the surface of such a substrate, the film needs to be deformed to match the surface shape of the substrate. When the film is deformed, a large tensile force may be generated partially in the conductive layer. The tensile force causes breakage of the conductive layer, and a decrease in conductivity becomes a problem. Furthermore, when forming a conductive circuit on a substrate having such an uneven surface or a curved surface, it is necessary to integrate the film and the substrate after or at the same time as deforming the film having the conductive layer, but in this integration process, stress is applied to the conductive circuit due to friction with the plastic substrate at high temperature. The stress at high temperature also causes breakage of the conductive layer, and a decrease in conductivity becomes a problem.
In contrast, the method of Patent Document 4 provides the conductive ink material with resistance to the thermoforming process, thus resolving the above-mentioned problem of reduced conductivity due to stress at high temperatures. However, the conductive circuit formed on the surface of a three-dimensional substrate by this method has a direct contact between the resin molded body and the conductive layer, and the adhesion at the boundary between them is not necessarily sufficient, and in fact, extremely fine voids may occur. For this reason, when this conductive circuit integrated molded product is used for a long period of time under harsh conditions as a practical product, the occurrence of short circuits between circuits due to ion migration over time becomes a problem.

The present invention has been made in consideration of these circumstances, and aims to provide a molded film that suppresses the decrease in conductivity due to tensile force and stress at high temperatures during the molding process and has excellent resistance to ion migration between conductive patterns even after molding, as well as a molded body that has excellent conductivity and can retain circuit characteristics even when used under harsh conditions for long periods of time, and a method for manufacturing the same.

The present invention provides a molded film for forming a printed conductive circuit on a substrate surface having an uneven surface or a three-dimensional curved surface, the printed conductive circuit being covered with an insulating layer,
A molded film having a conductive layer and an insulating layer on a base film,
the conductive layer is a cured product of a conductive resin composition containing a resin (A1), a solvent (B1), and conductive particles (C);
the insulating layer is a cured product of an insulating resin composition containing a resin (A2) and a solvent (B2),
The volume resistivity of the insulating layer is 1×10 ¹⁰ Ω·cm or more and less than 1×10 ¹⁷ Ω·cm;
The present invention relates to a molded film, wherein the solvent (B2) contains a solvent (b2) which satisfies the following condition (1) and any one of conditions selected from the group consisting of condition (2-1), condition (2-2), and condition (2-3).
(1) The boiling point is 180°C or more and less than 300°C. (2-1) The HSP (Hansen solubility parameter) is
14.0≦δd≦20.0 and 5.0≦δp≦10.0 and 9.5≦δh≦20.0
(2-2) HSP (Hansen solubility parameter) is
14.0≦δd≦19.0 and 4.0<δp≦5.0 and 0.0≦δh≦8.0
(2-3) HSP (Hansen solubility parameter) is
14.0≦δd≦19.0 and 0.0≦δp≦4.0 and 0.0≦δh≦9.0

The present invention also relates to the above-mentioned molded film, in which the base film is a film selected from the group consisting of polycarbonate, polymethyl methacrylate, polypropylene, and polyethylene terephthalate, or a laminate film of these.

The present invention also relates to the molded film, in which the proportion of solvent (b2) in solvent (B2) is 20% by weight to 100% by weight.

The present invention also relates to the above molded film, in which the resin (A1) is a resin having a cyclic structure in the main chain structure.

The present invention also relates to the above molded film, in which the resin (A1) is a resin having an aromatic ring structure in the main chain structure.

The present invention also relates to the molded film, in which the resin (A1) is a resin having an aromatic ester structure derived from an aromatic carboxylic acid in the main chain structure.

The present invention also relates to the above-mentioned molded film having a conductive layer and an insulating layer, in this order, on each side of the base film.

The present invention also relates to the above molded film further comprising a second conductive layer and a second insulating layer in this order on the insulating layer.

The present invention also relates to a molded article in which a molded film molded into a predetermined shape is laminated on a substrate so that the insulating layer surface is in contact with the substrate surface, or so that the base film surface is in contact with the substrate surface, and a printed conductive circuit covered with an insulating layer is formed on the substrate surface having an uneven surface or a three-dimensional curved surface, and the molded film is for use in the molded film.

The present invention also relates to a method for producing a molded body, which includes the steps of placing the molded film on a substrate and integrating the molded film with the substrate by an overlay molding method.

The present invention also relates to a method for producing a molded body, which includes the steps of: forming the molded film into a predetermined shape; placing the molded film in an injection molding die; and forming a substrate by injection molding and integrating the molded film with the substrate.

The present invention also relates to a method for producing a molded body, which includes the steps of placing the molded film in a mold for injection molding, and molding a substrate by injection molding while transferring the conductive layer in the molded film to the substrate.

The present invention can provide a molded film that suppresses the decrease in electrical conductivity due to tensile force and stress at high temperatures during the molding process and has excellent resistance to ion migration between conductive patterns even after molding, as well as a molded body that has excellent electrical conductivity and can retain circuit characteristics even when used under harsh conditions for a long period of time, and a method for manufacturing the same.

FIG. 2 is a schematic cross-sectional view showing an example of a molded film according to the present embodiment. FIG. 2 is a schematic cross-sectional view showing another example of the molded film of the present embodiment. FIG. 2 is a schematic cross-sectional view showing another example of the molded film of the present embodiment. FIG. 2 is a schematic cross-sectional view showing another example of the molded film of the present embodiment. 1A to 1C are schematic process diagrams showing an example of a first manufacturing method of a molded body. FIG. 4 is a schematic process diagram showing another example of the second manufacturing method of a molded body. 5A to 5C are schematic process diagrams showing another example of the third manufacturing method of a molded body.

The molded film, molded article, and manufacturing method thereof according to the present embodiment will be described in detail below.
In the present embodiment, the term "cured product" refers not only to products that have been cured by chemical reaction, but also to products that have been cured without chemical reaction, such as products that have been hardened by evaporation of a solvent.

[Formed film]
The molded film of this embodiment is a molded film having a conductive layer and an insulating layer on a base film,
The conductive layer is a cured product of a conductive resin composition, and the insulating layer is a cured product of an insulating resin composition.
According to the molded film of this embodiment, a molded article can be obtained in which a conductive circuit is formed on any substrate surface, such as an uneven surface or a curved surface.
The layer structure of the molded film of this embodiment will be described with reference to Figures 1 and 2. Figures 1 and 2 are schematic cross-sectional views showing an example of the molded film of this embodiment.
The molded film 10 shown in the example of Fig. 1 has a conductive layer 2 on a base film 1, and an insulating layer 3 on the conductive layer 2. The conductive layer 2 may be formed on the entire surface of the base film 1, or may be formed in a desired pattern as in the example of Fig. 1. The insulating layer 3 may be formed on the entire surfaces of the base film 1 and the conductive layer 2, or may be formed in a desired pattern so as to cover a portion of the conductive layer 2 as in the example of Fig. 1.
The molded film 10 shown in the example of Fig. 2 has a decorative layer 3 on a base film 1, a conductive layer 2 on the decorative layer 3, and an insulating layer 3 on the conductive layer 2. As shown in the example of Fig. 2, the molded film 10 may also have, on the conductive layer 2, an electronic component 4 and a pin 5 for connecting to an extraction circuit.
The molded film 10 shown in the example of Fig. 3 has a conductive layer 2 on a base film 1, and an insulating layer 3 on the conductive layer 2. It also has a second conductive layer 7 on the opposite surface of the base film 1, and a second insulating layer 8 on the second conductive layer 7. The second conductive layer 7 may also be formed on the entire surface of the base film 1, or may be formed in a desired pattern as in the example of Fig. 1. The second insulating layer 8 may also be formed on the entire surfaces of the base film 1 and the second conductive layer 7, or may be formed in a desired pattern so as to cover a part of the second conductive layer 7 as in the example of Fig. 3.
The molded film 10 shown in the example of FIG. 4 has a conductive layer 2 on a base film 1, an insulating layer 3 on the conductive layer 2, a second conductive layer 7 on the insulating layer 3, and a second insulating layer 8 on the second conductive layer 7. In this case, the second conductive layer 7 may be formed on the entire surface of the base film 1 and the insulating layer 3, or, if there is an exposed portion of the conductive layer 2 that is not covered by the insulating layer 3 as in the example of FIG. 4, the second conductive layer 7 may be provided in a desired pattern so as to be in partial contact with the conductive layer 2. It is also possible that the second insulating layer 8 is not in contact with any part of the conductive layer 2. The second insulating layer 8 may also be formed on the entire surface of the base film 1, the conductive layer 2, the insulating layer 3, and the second conductive layer 7, or may be formed in a desired pattern so as to cover a part of the second conductive layer 7 as in the example of FIG. 4.
In addition, although not shown in the figure, when the molded film 10 of this embodiment has a decorative layer 3, in addition to the example of Figure 2, it may have a layer structure having a decorative layer 3 on one side of the base film 1 and a conductive layer 2 on the other side.
The molded film of the present embodiment comprises at least a base film, a conductive layer, and an insulating layer, and may have other layers as required. Each layer of such a molded film will be described below.

<Base film>
In this embodiment, the base film can be appropriately selected from those having flexibility and extensibility to such an extent that it can follow the shape of the substrate surface under the molding temperature conditions when the substrate is formed, and it is preferable to select the base film according to the use of the molded body and the manufacturing method of the molded body.
For example, when the overlay molding method or the film insert method described below is adopted as a method for producing a molded body, the base film remains in the molded body, so the base film can be selected taking into consideration its function as a protective layer for the conductive layer.
On the other hand, when an in-mold transfer method, which will be described later, is employed as a method for producing a molded article, it is preferable to select a base film having releasability.

The base film can be appropriately selected from the above viewpoints, and may be, for example, a film such as polycarbonate, polymethyl methacrylate, polyethylene terephthalate, polystyrene, polyimide, polyamide, polyethersulfone, polyethylene naphthalate, polybutylene terephthalate, polyvinyl chloride, polyethylene, polypropylene, cycloolefin polymer, ABS (acrylonitrile-butadiene-styrene copolymer resin), AES (acrylonitrile-ethylene-styrene copolymer resin), Kaidac (acrylic modified vinyl chloride resin), modified polyphenylene ether, and a polymer alloy consisting of two or more of these resins, or a laminated film thereof. Among them, a film selected from polycarbonate, polymethyl methacrylate, polypropylene, and polyethylene terephthalate, or a laminated film thereof is preferable. As the laminated film, a laminated film of polycarbonate and polymethyl methacrylate is preferable.
The method for producing the laminated film of polycarbonate and polymethyl methacrylate is not particularly limited. A polycarbonate film and a polymethyl methacrylate film may be laminated together, or polycarbonate and polymethyl methacrylate may be co-extruded to form a laminated film.
It is also preferable that the surface of these base films is subjected to a modification treatment such as a corona treatment.

In addition, if necessary, an anchor coat layer may be provided on the base film and the conductive resin composition may be printed on the anchor coat layer for the purpose of improving the printability of the conductive resin composition. The anchor coat layer is not particularly limited as long as it has good adhesion to the base film and further to the conductive resin composition and follows the film during molding, and organic fillers such as resin beads and inorganic fillers such as metal oxides may also be added as necessary. The method of providing the anchor coat layer is not particularly limited, and it can be obtained by coating, drying, and curing using a conventionally known coating method.
Furthermore, if necessary, in order to prevent the surface of the molded body from being scratched, a hard coat layer may be provided on the base film, and a conductive resin composition and, if necessary, a decorative layer may be printed on the opposite side. The hard coat layer is not particularly limited as long as it has good adhesion to the base film and surface hardness and follows the film during molding, and organic fillers such as resin beads and inorganic fillers such as metal oxides may also be added as necessary. The method of providing the hard coat layer is not particularly limited, and it can be obtained by applying, drying, and curing using a conventionally known coating method.

In addition, if the molded film of this embodiment has a decorative layer, it is preferable to select a base film that has transparency.

The thickness of the base film is not particularly limited, but can be, for example, 10 μm or more and 500 μm or less, and preferably 20 μm or more and 450 μm or less.

<Conductive Layer>
In the molded film of this embodiment, the conductive layer is a cured product of a conductive resin composition described below.
The method for forming the conductive layer is not particularly limited, but in this embodiment, it is preferable to form it by screen printing, pad printing, stencil printing, screen offset printing, dispenser printing, gravure offset printing, reverse offset printing, or microcontact printing, and it is more preferable to form it by screen printing.
In the screen printing method, it is preferable to use a fine mesh screen, particularly a fine mesh screen of about 300 to 650 mesh, in order to meet the demands of high-definition conductive circuit patterns. In this case, the open area of the screen is preferably about 20 to 50%. The screen line diameter is preferably about 10 to 70 μm.
Types of screens include polyester screens, combination screens, metal screens, nylon screens, etc. When printing with a highly viscous paste, a high-tension stainless steel screen can be used.
The squeegee for screen printing may be round, rectangular, or square, and an abrasive squeegee may be used to reduce the attack angle (the angle between the plate and the squeegee during printing). Other printing conditions may be appropriately designed from conventionally known conditions.

The conductive resin composition is printed by screen printing, and then heated to dry it, and if a crosslinking agent is contained, a crosslinking reaction is carried out to harden it.
In order to sufficiently volatilize the solvent and promote the crosslinking reaction, the heating temperature is preferably 80 to 230° C. and the heating time is preferably 10 to 120 minutes, thereby making it possible to obtain a patterned conductive layer.

The thickness of the conductive layer can be adjusted appropriately according to the required conductivity, etc., and is not particularly limited, but can be, for example, 0.5 μm or more and 20 μm or less, and preferably 1 μm or more and 15 μm or less.

[Conductive resin composition]
The conductive resin composition used in the molded film of this embodiment contains at least a resin (A1), a solvent (B1), and conductive particles (C), and may further include a crosslinking agent if necessary. The composition may contain the agent (D) and other components.
Each component of the conductive resin composition for molded films will now be described.

<Resin (A1)>
The conductive resin composition of this embodiment contains a binder resin (A1) in order to provide film-forming properties and adhesion to the base film or decorative layer. In addition, in this embodiment, the resin (A1) is contained, so that the conductive layer can be given flexibility. Therefore, the conductive layer is prevented from breaking due to stretching by containing the resin (A1).

The resin (A1) can be appropriately selected from resins used for conductive resin compositions.
Examples of the resin (A1) include acrylic resins, vinyl ether resins, polyether resins, polyester resins, polyurethane resins, epoxy resins, phenoxy resins, polycarbonate resins, polyvinyl chloride resins, polyolefin resins, styrene block copolymer resins, polyamide resins, and polyimide resins. These may be used alone or in combination of two or more.

In this embodiment, the resin (A1) is preferably a resin having a cyclic structure in the main chain structure. In this case, when an insulating composition containing a solvent (b1) described later is laminated on the conductive layer, excessive solvent infiltration from the insulating composition can be suppressed, which is preferable in that it can suppress a decrease in the conductivity of the conductive layer and a decrease in the conductivity of the molded film during thermal molding under high temperature conditions.

In the present invention, the cyclic structure refers to an alicyclic structure, an aromatic ring structure, or a heterocyclic structure in which one ring is a 4- to 14-membered ring.
Examples of the alicyclic structure include monocyclic structures such as a cyclobutane ring, a cyclopentane ring, a cyclohexane ring, a cyclohexene ring, a cycloheptane ring, a cyclooctane ring, a cyclodecane ring, and a cyclotetradecane ring, and condensed ring structures such as a bornane ring, an isobornane ring, an adamantane ring, a decalin ring, and a steroid skeleton.
Examples of the aromatic ring structure include monocyclic structures such as a benzene ring, a furan ring, a 1,4-dioxine ring, a pyrrole ring, a pyridine ring, a pyrazine ring, a triazine ring, an imidazole ring, a pyrazole ring, an oxazole ring, a thiazole ring, a thiophene ring, a triazole ring, and a tetrazole ring, and condensed ring structures such as a naphthalene ring, a tetralin ring, an azulene ring, an anthracene ring, a perylene ring, an indane ring, an indole ring, a benzofuran ring, a benzimidazole ring, and a benzoxazole ring. As in the above examples, in the present invention, a structure in which an aromatic ring structure is condensed or directly bonded to an alicyclic structure, and a heterocyclic structure exhibiting aromaticity are all considered to be aromatic ring structures.
In the present invention, the heterocyclic structure refers to a heteroatom-containing (non-carbon atom) ring structure other than the above-mentioned aromatic ring structures, and examples thereof include a tetrahydrofuran ring, a pyran ring, a tetrahydropyran ring, a pyrrolidine ring, a piperidine ring, a piperazine ring, and an isocyanurate ring.
The linking site of the cyclic structure in the main chain structure of the resin (A) is not particularly limited, and it is sufficient that the cyclic structure is linked to the main chain via a total of two or more covalent bonds from any one or two atoms constituting the cyclic structure.

In addition, the resin (A1) is more preferably a resin containing an aromatic ring structure as a cyclic structure in the main chain structure, which is preferable because it can suppress not only excessive solvent infiltration from the insulating composition but also residual solvent after drying, and can suppress a decrease in electrical conductivity during thermoforming under higher temperature conditions.
Furthermore, it is particularly preferred that the resin (A1) is a resin containing an aromatic ester structure derived from an aromatic carboxylic acid in the main chain structure, which is particularly preferred because it is superior in the above-mentioned solvent infiltration and solvent remaining after drying, and the decrease in electrical conductivity during thermoforming and the generation of microvoids are further suppressed, resulting in excellent ion migration resistance of the produced molded product.

In this embodiment, resin (A1) may have two or more substituents selected from hydroxyl group, amino group, carboxyl group, and acid anhydride group in one molecule.When resin (A1) has a functional group selected from hydroxyl group, amino group, carboxyl group, and acid anhydride group, its functional group value is preferably 1 mgKOH/g or more and 400 mgKOH/g or less, and preferably 2 mgKOH/g or more and 350 mgKOH/g or less.The details of the calculation method of functional group value will be described in the examples below.
When the resin (A1) has a plurality of types of functional groups, the functional value is the sum of the functional groups. For example, when the resin (A1) has a hydroxyl group and a carboxyl group, the functional value represents the sum of the hydroxyl value and the acid value of the resin (A1).

In this embodiment, the resin (A1) may be synthesized by the methods described in the Examples below or other known methods, or a commercially available product having the desired physical properties may be used. In this embodiment, the resin (A1) may be used alone or in combination of two or more types.

The content of resin (A1) in the conductive resin composition of this embodiment may be adjusted appropriately according to the application, etc., and is not particularly limited. It is preferably 5% by mass or more and 50% by mass or less, and more preferably 10% by mass or more and 40% by mass or less, based on the total amount of solids contained in the conductive resin composition. If the content of resin (A1) is equal to or more than the above lower limit, the film-forming property and adhesion to the base film, etc. are improved, and flexibility can be imparted to the conductive layer. If the content of resin (A1) is equal to or less than the above upper limit, the content of conductive fine particles (D) can be relatively increased, and a conductive layer with excellent conductivity can be formed.

<Solvent (B1)>
The solvent (B1) is not particularly limited, but from the viewpoint of continuous screen printing, it is preferable that the boiling point is 180° C. or more and 270° C. or less. Examples of the solvent include, but are not limited to, diethylene glycol monoethyl ether acetate, diethylene glycol monobutyl ether, diethylene glycol monobutyl ether acetate, dipropylene glycol monomethyl ether acetate, gamma butyrolactone, isophorone, and tetralin. In this embodiment, the solvent (B1) can be used alone or in combination of two or more.

<Conductive fine particles (C)>
The conductive fine particles (C) are particles that exhibit conductivity when a plurality of conductive fine particles come into contact with each other in the conductive layer. In this embodiment, the conductive fine particles are appropriately selected from those that can obtain conductivity without being heated at a high temperature. It is used selectively.
The conductive fine particles used in this embodiment include metal fine particles, carbon fine particles, conductive oxide fine particles, and the like.
Examples of metal fine particles include powders of metal elements such as gold, silver, copper, nickel, chromium, palladium, rhodium, ruthenium, indium, aluminum, tungsten, malbutene, and platinum, as well as powders of copper-nickel alloys, silver-palladium alloys, Examples of the fine carbon particles include alloy powders such as copper-tin alloy, silver-copper alloy, and copper-manganese alloy, and metal-coated powders in which the surface of the above-mentioned metal powders or alloy powders is coated with silver or the like. Examples of the conductive oxide particles include carbon black, graphite, and carbon nanotubes. Examples of the conductive oxide particles include silver oxide, indium oxide, tin oxide, zinc oxide, and ruthenium oxide.

In this embodiment, it is preferable to include one or more conductive fine particles selected from silver powder, copper powder, silver-coated powder, copper alloy powder, conductive oxide powder, and carbon fine particles. By using these conductive fine particles (C), a conductive layer with excellent conductivity can be formed without sintering, and a conductive layer with excellent extensibility and conductivity retention performance when molded into a three-dimensional shape as a molded film described later can be formed.

The shape of the conductive fine particles (C) is not particularly limited, but is preferably flake-like or chain-aggregated. In the case of flake-like, there is no particular limit as long as it is a two-dimensional flat shape. In the present invention, "flake-like" refers to all two-dimensional flat shapes called scale-like, scale-like, plate-like, flat, sheet-like, etc. Among them, from the viewpoints of maintaining printability, maintaining conductivity during molding and tension, and resistance to frictional stress stress with the base plastic at high temperatures in the integration process with the plastic substrate, those with an aspect ratio of 3 to 500 are particularly preferred. In the case of chain-aggregated, there is no particular limit as long as it is an indefinite shape in which fine spherical particles are bonded to each other. In the present invention, "chain-aggregated" refers to all indefinite shapes formed by the settlement of spherical particles called bonded spherical, chain-aggregated, aggregated, etc. Chain-aggregated is also particularly preferred from the viewpoints of maintaining printability, maintaining conductivity during molding and tension, and resistance to frictional stress stress with the base plastic at high temperatures in the integration process with the plastic substrate.

The average particle diameter of the conductive fine particles is not particularly limited, but from the viewpoints of maintaining dispersibility and printability in the conductive resin composition, maintaining conductivity during molding, and resistance to an injection molding process using a molten resin or high-temperature tensile resistance of a molded resin, the average particle diameter is preferably 0.5 μm or more and 30 μm or less, and more preferably 1 μm or more and 15 μm or less.
In this embodiment, the average particle diameter of the conductive fine particles (C) is calculated as follows. In accordance with the laser diffraction/scattering method described in JIS M8511 (2014), a laser diffraction/scattering type particle size distribution measuring device (Microtrack 9220FRA manufactured by Nikkiso Co., Ltd.) was used to add an appropriate amount of conductive fine particles (C) to an aqueous solution containing 0.5 volume% of a commercially available surfactant polyoxyethylene octylphenyl ether (Triton X-100 manufactured by Roche Diagnostics K.K.) as a dispersant, and the solution was irradiated with 40 W ultrasonic waves for 180 seconds while stirring, after which the measurement was performed. The obtained median diameter (D50) value was taken as the average particle diameter of the conductive fine particles (C).

In the present embodiment, the conductive fine particles (C) may be used alone or in combination of two or more kinds.
The content ratio of the conductive fine particles (C) in the conductive resin composition of this embodiment is not particularly limited and can be appropriately adjusted according to the application, etc., but is preferably 50% by mass or more and 85% by mass or less, and more preferably 55% by mass or more and 80% by mass or less, based on the total amount of solids contained in the conductive resin composition. If the content ratio of the conductive fine particles (C) is equal to or more than the above lower limit, a conductive layer with excellent conductivity can be formed. In addition, if the content ratio of the conductive fine particles (C) is equal to or less than the above upper limit, the content ratio of the resin (A1) can be increased, film-forming properties and adhesion to the base film, etc. can be improved, and flexibility can be imparted to the conductive layer.

<Optional ingredients>
The conductive resin composition of the present invention may further contain other components as necessary, such as the crosslinking agent (D), dispersants, friction resistance improvers, infrared absorbing agents, ultraviolet absorbing agents, fragrances, antioxidants, organic pigments, inorganic pigments, defoamers, silane coupling agents, plasticizers, flame retardants, moisturizing agents, etc.

<Crosslinking Agent (D)>
In this embodiment, a crosslinking agent (D) may be used as an optional component to crosslink the resin (A1). The crosslinking agent (D) may be appropriately selected from those having two or more reactive functional groups in one molecule that can form a crosslink with the reactive functional group of the resin (A1). Examples of such reactive functional groups include an epoxy group, an isocyanate group, a blocked isocyanate group, an alkyloxyamino group, an aziridinyl group, an oxetanyl group, a carbodiimide group, and a β-hydroxyalkylamide group.

<Method of producing conductive resin composition>
The method for producing the conductive resin composition of this embodiment may be any method for dissolving or dispersing the resin (A1), the solvent (B1), the conductive fine particles (C), the crosslinking agent (D) used as necessary, and other components, and the conductive resin composition can be produced by mixing them by a known mixing means.

<Insulating layer>
In the molded film of this embodiment, the insulating layer has a volume resistivity of 1×10 ¹⁰ Ω·cm or more and less than 1×10 ¹⁷ Ω·cm, and is a cured product of an insulating resin composition described below.
By covering the conductive layer with the insulating layer, it is possible to prevent friction damage to the conductive layer during the manufacturing process. It also plays a role as a heat stress resistant protective layer that prevents friction stress with the base plastic at high temperatures from being directly applied to the conductive layer. Furthermore, it is possible to ensure insulation during long-term continuous current flow between the conductive layer patterns, because the insulating resin composition reliably penetrates and seals every corner of the conductive layer, which usually has fine irregularities, and the insulating layer also serves as an adhesive layer with the resin molded body, making it possible to more reliably block moisture, sulfur compounds, and other corrosive gases from the outside. It is also possible to suppress physical peeling of the molded film from the resin molded body base material against external impacts, etc.
The method for forming the insulating layer is not particularly limited, but in this embodiment, it is preferable to form it by screen printing, pad printing, stencil printing, screen offset printing, dispenser printing, gravure offset printing, reverse offset printing, or microcontact printing, and it is more preferable to form it by screen printing.
In the screen printing method, it is preferable to use a screen with a specific mesh size, particularly preferably a mesh size of about 120 to 400 mesh, so that the conductive circuit pattern can be reliably insulated from the outside and a certain degree of patterning precision can be ensured. In this case, the open area of the screen is preferably about 20 to 50%. The screen wire diameter is preferably about 10 to 70 μm.
Types of screens include polyester screens, combination screens, metal screens, nylon screens, etc. When printing with a highly viscous paste, a high-tension stainless steel screen can be used.
The squeegee for screen printing may be round, rectangular, or square, and an abrasive squeegee may be used to reduce the attack angle (the angle between the plate and the squeegee during printing). Other printing conditions may be appropriately designed from conventionally known conditions.

After the insulating resin composition is printed by screen printing, it is heated to dry and, if a crosslinking agent is contained, to cause a crosslinking reaction and harden.
For sufficient volatilization of the solvent and crosslinking reaction, the heating temperature is preferably 80 to 230°C and the heating time is preferably 10 to 120 minutes. This makes it possible to obtain a patterned insulating layer. The patterned insulating layer may cover the entire surface of the conductive pattern, but the insulating layer may be provided so as to cover a part of the conductive pattern while leaving the surface of the conductive pattern exposed so that the conductive pattern can be connected to an external device when used as a circuit.

The thickness of the insulating layer can be adjusted appropriately depending on the required insulation properties, etc., and is not particularly limited, but can be, for example, 5 μm or more and 50 μm or less, and preferably 8 μm or more and 30 μm or less.

[Insulating resin composition]
The insulating resin composition used in the molded film of this embodiment contains at least the resin (A2) and the solvent (B2), and may further contain other components as necessary.
Each component of the insulating resin composition for molded films will now be described.

<Resin (A2)>
The insulating resin composition of the present embodiment contains a binder resin (A2) in order to ensure film-forming properties and insulating properties, and to impart adhesion to the conductive layer and the base film or decorative layer.
In addition, in this embodiment, the inclusion of the resin (A2) can impart mechanical cushioning properties based on flexibility and toughness to the insulating layer when the insulating layer covers the conductive layer, and therefore the inclusion of the resin (A2) can suppress not only the breakage of the insulating layer due to stretching, but also the breakage of the conductive layer.

The resin (A2) can be appropriately selected from resins used for insulating resin compositions.
Examples of the resin (A2) include acrylic resins, vinyl ether resins, polyether resins, polyester resins, polyurethane resins, epoxy resins, phenoxy resins, polycarbonate resins, polyolefin resins, styrene block copolymer resins, polyamide resins, and polyimide resins. These may be used alone or in combination of two or more.

In this embodiment, the resin (A2) preferably does not have a halogen element in its structure or has an extremely low content of the halogen element. The absence of a halogen element in its structure is advantageous in that when used in a laminated state with a conductive layer, the ion migration resistance under harsh conditions is even better. Furthermore, in this embodiment, the resin (A2) is particularly preferably a resin having an ester bond in its repeating structure and a weight average molecular weight of 5,000 to 200,000. By using a resin having an ester bond in its repeating structure and a weight average molecular weight of 5,000 to 200,000, the insulating layer efficiently wets and spreads on both the molded film and the conductive particle surface of the conductive layer, and adheres strongly, and by expressing appropriate elasticity under high temperature conditions, it is possible to achieve both a high level of protection of the conductive layer from elongation during thermoforming and a high level of ion migration resistance between the conductive patterns after the molded body is formed.

In this embodiment, it is preferable that the resin (A2) has any crosslinkable functional group, particularly two or more functional groups selected from hydroxyl groups, amino groups, and acid anhydride groups in one molecule. In this case, the resin (A2) can be three-dimensionally crosslinked by appropriately combining with the crosslinking agent (D) described later, and can be used preferably in applications requiring hardness. Furthermore, when the resin (A2) has a functional group selected from hydroxyl groups, amino groups, and acid anhydride groups, the crosslinking enhances the mechanical cushioning performance of the insulating layer based on flexibility and toughness when the insulating layer covers the conductive layer, and the extensibility of the insulating layer itself during thermoforming can be achieved at a high level in a well-balanced manner, making it even more suitable for use.

When the resin (A2) has a functional group selected from a hydroxy group, an amino group, a carboxyl group, and an acid anhydride group, the functional group value is preferably 1 mgKOH/g or more and 400 mgKOH/g or less, and more preferably 2 mgKOH/g or more and 350 mgKOH/g or less. The details of the calculation method of the functional group value will be described in the examples described later.
When the resin (A2) has a plurality of types of functional groups, the functional value is the sum of the functional groups. For example, when the resin (A2) has a hydroxyl group and a carboxyl group, the functional value represents the sum of the hydroxyl value and the acid value of the resin (A2).

In this embodiment, the resin (A2) may be synthesized by the methods described in the Examples below or other known methods, or a commercially available product having the desired physical properties may be used. In this embodiment, the resin (A2) may be used alone or in combination of two or more types.

The content of resin (A2) in the insulating resin composition of this embodiment may be adjusted appropriately depending on the application, etc., and is not particularly limited. However, it is preferably 50% by mass or more and 100% by mass or less, and more preferably 70% by mass or more and 100% by mass or less, based on the total amount of solids contained in the conductive resin composition. If the content of resin (A2) is equal to or more than the above lower limit, the film-forming property and adhesion to the base film, etc. are improved, and flexibility can be imparted to the conductive layer.

<Solvent (B2)>
The solvent (B2) used in the insulating resin composition of this embodiment includes a solvent (b2) that satisfies the following condition (1) and any one of the conditions selected from the group consisting of condition (2-1), condition (2-2), and condition (2-3).
(1) The boiling point is 180°C or more and less than 300°C. (2-1) The HSP (Hansen solubility parameter) is
14.0≦δd≦20.0 and 5.0≦δp≦10.0 and 9.5≦δh≦20.0
(2-2) HSP (Hansen solubility parameter) is
14.0≦δd≦19.0 and 4.0<δp≦5.0 and 0.0≦δh≦8.0
(2-3) HSP (Hansen solubility parameter) is
14.0≦δd≦19.0 and 0.0≦δp≦4.0 and 0.0≦δh≦9.0
By including the above-mentioned solvent (b2), when the insulating composition is laminated and printed on the conductive layer, penetration of the solvent (B2) into the conductive layer and the resulting deterioration of the conductive layer are suppressed, and thus it is possible to produce a molded film in which the decrease in conductivity of the conductive layer due to tensile force is suppressed.
Among them, it is particularly preferable to use a solvent (b2) that satisfies the conditions (1) and (2-1), since this makes it possible to further suppress the infiltration of the solvent (B2) into the conductive layer and the resulting deterioration of the conductive layer.

Specific examples of such a solvent (b2) that satisfies the conditions (1) and (2-1) include diethylene glycol monomethyl ether (boiling point 194° C., δd=16.2, δp=7.8, δh=12.6), diethylene glycol monoethyl ether (boiling point 202° C., δd=16.1, δp=9.2, δh=12.2), diethylene glycol monobutyl ether (boiling point 231° C., δd=16.0, δp=7.0, δh=10.6), triethylene glycol monomethyl ether (boiling point 249° C., δd=16.2, δp=7.6, δh=12.5), benzyl alcohol (boiling point 205° C., δd=18.4 , δp = 6.3, δh = 13.7), dipropylene glycol monopropyl ether (boiling point 212 ° C, δd = 15.5, δp = 5.7, δh = 11.2), diethylene glycol monopropyl ether (boiling point 214 ° C, δd = 16.0, δp = 7.2, δh = 11.3), dipropylene glycol monomethyl ether (boiling point 190 ° C, δd = 15.5, δp = 5.7, δh = 11.2), tripropylene glycol monomethyl ether (boiling point 242 ° C, δd = 15.3, δp = 5.5, δh = 10.4) phenoxyethanol (boiling point 247 ° C, δd = 17.8, δp = 5.7, δh = 14.3), and the like.
Examples of compounds that satisfy the conditions (1) and (2-2) include diethylene glycol dibutyl ether (boiling point 256° C., δd=15.8, δp=4.4, δh=4.7) and dipropylene glycol monomethyl ether acetate (boiling point 213° C., δd=16.3, δp=4.9, δh=8.0).
Examples of compounds that satisfy the conditions (1) and (2-3) include triethylene glycol dimethyl ether (boiling point 220° C., δd=15.8, δp=2.3, δh=8.2) and terpinyl acetate (boiling point 220° C., δd=16.3, δp=3.6, δh=4.8).

By including the specific solvent (b2) in an amount of 20% by mass or more relative to the total solvent, the solvent penetration, dissolution or shrinkage of the resin film to be the base film is suppressed, and a molded film in which the decrease in conductivity due to tensile force is suppressed can be produced. The proportion of the solvent (C') may be 20% by mass or more and 100% by mass or less relative to the total solvent, preferably 40% by mass or more, and more preferably 60% by mass or more.
In the present embodiment, the solvent (B2) may be used alone or in combination of two or more kinds.

In addition, the solvent (B2) may contain a solvent other than the above-mentioned solvent (b2) in an amount of less than 80 mass %, but the amount of the solvent is preferably 60 mass % or less, more preferably 30 mass % or less, based on the total amount of the solvent (B2), and even more preferably 0 mass %, i.e., substantially none of the solvent is contained.
Examples of the solvent other than the above solvent (b2) include diethylene glycol monoethyl ether acetate, gamma butyrolactone, and isophorone.

The present inventors have investigated screen-printable conductive resin compositions and insulating synthetic compositions in order to produce molded films that can be applied to uneven substrate surfaces and have process suitability for integration with plastic substrates. In order to apply the compositions to the production of molded films, the inventors have adjusted and investigated the volume resistivity and solvent composition of the conductive resin composition and insulating synthetic composition in various ways, and have found that the presence or absence of breakage and the magnitude of change in resistance value that occurs when the obtained molded film is stretched at a moldable high temperature, and the ion migration characteristics over time when the conductive circuit integrated molded product is used under long-term harsh conditions with current flow, differ depending on the resin structure of the conductive resin composition and, in particular, the specific solvent contained in the insulating synthetic composition.
Based on such findings, the present inventors conducted a study and confirmed that when an insulating layer with a low volume resistivity is laminated on a conductive layer, a significantly larger ion migration occurs in the conductive circuit integrated molded product compared to a flat film circuit board. In addition, when an insulating resin composition containing a solvent component belonging to a specific HSP (Hansen solubility parameter) range is printed and heated and dried to laminate an insulating layer, and in addition, when the resin of the conductive resin composition is a resin having a cyclic structure in the main chain, when the molded film is deformed by pulling at a high temperature corresponding to its softening point, cracks and local deformation of the conductive layer occur more frequently, and as a result, when electricity is continuously applied near the conductive layer under high temperature and high humidity conditions, the occurrence of black silver oxide due to ion migration increases, the insulation resistance value between the conductive patterns decreases, and the probability of leak touch (insulation breakdown) increases. The same was true when a conductive layer and an insulating layer were provided on the decorative layer.

Even if such an insulating layer with a somewhat low volume resistivity is laminated on the conductive layer, or if the molded film has a conductive layer and an insulating layer that cracks or local deformation of the conductive layer and ion migration are more likely to occur when the molded film is used alone as a flat film circuit board or when it is used in a bent state on a two-dimensional curved surface, there is no problem. However, when the molded film is used as a molded film that is integrated with the shape of a non-flat substrate surface, such as an uneven shape or a three-dimensional curved shape, the molded film will be deformed. Therefore, it is predicted that the deformation stress generated in the conductive layer and the insulating layer due to the deformation of the resin film is concentrated on the conductive layer or the conductive layer/insulating layer interface, causing peeling or disconnection, thereby reducing the conductivity of the conductive layer.
In addition, the uneven surface and three-dimensional curved surface in the present invention refer not only to a surface having a gently curved cross section, but also to a three-dimensional surface having an acute angle or a rectangular shape in general. In other words, it refers to a three-dimensional shape that cannot be established only by deforming a plane without expanding or contracting, such as a hemispherical, conical, cylindrical, or rectangular prism. In addition, when a certain three-dimensional shape has elements of both the above-mentioned plane or two-dimensional curved surface and a three-dimensional curved surface in a continuous three-dimensional surface, for example, a three-dimensional shape in which one or more partial hemispherical shapes are combined with a plane shape, it is a three-dimensional shape that cannot be established by deforming a plane without expanding or contracting as a whole, so it is also considered to be a three-dimensional curved surface. In other words, the uneven surface and three-dimensional curved surface in the present invention cannot be realized by bending a flexible substrate or the like, and are shapes that can be realized, for example, by shaping a moldable film by three-dimensional molding under heating.

As a result of intensive research based on these findings, the inventors have found that when a molded film having an insulating layer with a volume resistivity of 1 x 10 ¹⁰ Ω·cm or more and less than 1 x 10 ¹⁷ Ω·cm is used, the occurrence of ion migration is suppressed in a conductive circuit integrated molded product. In addition, when a molded film having an insulating layer formed from an insulating composition containing a solvent whose HSP (Hansen solubility parameter) satisfies any one of the conditions of 14.0≦δd≦20.0 and 5.0≦δp≦10.0 and 9.5≦δh≦20.0, or 14.0≦δd≦19.0 and 4.0<δp≦5.0 and 0.0≦δh≦8.0, or 14.0≦δd≦19.0 and 0.0≦δp≦4.0 and 0.0≦δh≦9.0 is used, the occurrence of cracks and local deformation in the conductive layer when the molded film is stretched under high temperature conditions is suppressed, and further, it has been found that in a conductive circuit integrated molded product in which a molten high-viscosity thermoplastic resin is pressure-bonded onto a molded film under high pressure, it is possible to suppress a decrease in insulation resistance value between conductive patterns due to ion migration and the occurrence of leak touch, thereby completing the present invention.
That is, in the molded film of the present invention, the volume resistivity of the insulating layer is 1×10 ¹⁰ Ω·cm or more and less than 1×10 ¹⁷ Ω·cm, and even when the molded film is used on an uneven substrate surface, the circuit deterioration due to ion migration is suppressed. This characteristic is particularly remarkable when a molded film having a conductive layer formed from a conductive resin composition containing a resin having a cyclic structure in the main chain is used. In addition, by using the molded film, a molded product can be obtained in which an insulating-coated conductive circuit is formed on any surface, such as an uneven surface or a curved surface, on a substrate made of a three-dimensional plastic having practical strength.

<Optional ingredients>
The insulating resin composition of the present invention may further contain other components as necessary. Examples of such other components include, in addition to the crosslinking agent (D), dispersants, friction resistance improvers, infrared absorbing agents, ultraviolet absorbing agents, fragrances, antioxidants, organic pigments, inorganic pigments, defoamers, silane coupling agents, plasticizers, flame retardants, and moisturizing agents. The crosslinking agent (D) may be the same as those listed in the conductive composition.

<Decorative layer>
The molded film of the present embodiment may have a decorative layer from the viewpoint of the design of the resulting molded article.
The decorative layer may be a layer having a single color, or may have any pattern.
For example, the decorative layer can be formed by preparing a decorative ink containing a coloring material, a resin, and a solvent, and then applying the decorative ink to the base film by a known printing method.
The coloring material may be appropriately selected from known pigments and dyes, and the resin may be appropriately selected from the resin (A2) in the insulating resin composition of the present embodiment.
The thickness of the decorative layer is not particularly limited, but may be, for example, from 0.5 μm to 10 μm, and preferably from 1 μm to 5 μm.

[Molded body]
The molded article of this embodiment is a molded article having at least a conductive layer laminated on a substrate, the conductive layer being a cured product of the conductive resin composition for molded films according to any one of claims 1 to 5. The molded article of this embodiment is formed from a molded film using the conductive resin composition for molded films of this embodiment, and therefore is a molded article having a conductive circuit formed on any surface, such as an uneven surface or a curved surface.
Hereinafter, three embodiments of the method for producing the molded article of the present embodiment will be described. Note that the molded article of the present embodiment may be produced using the conductive resin composition of the present embodiment, and is not limited to these methods.

<First manufacturing method>
A first method for producing a molded article according to the present embodiment includes the steps of: printing the conductive resin composition for a molded film according to the present embodiment on a base film and drying the composition to produce a molded film;
placing the formed film on a substrate;
and b) integrating the molded film and the substrate by an overlay molding process.
The following description will be given with reference to FIG. 3, but the method for producing the molded film is as described above, so the description will be omitted here.

5 is a schematic process diagram showing an example of a first manufacturing method of a molded body. Each of (A) to (C) of FIG. 5 illustrates a molded film 10 and a substrate 20 arranged in a chamber box of a TOM (Three Dimension Overlay Method) molding machine, and the chamber box is omitted in (B) and (C) of FIG. 5.
In the first manufacturing method, first, the substrate 20 is placed on the table of the lower chamber box 22. Next, the molded film 10 of the present embodiment is passed between the upper chamber box 21 and the lower chamber box 22 and placed on the substrate 20. At this time, the molded film 10 may be placed so that the conductive layer faces either the substrate 20 side or the opposite side to the substrate 20, and is selected depending on the final use of the molded body. Next, the upper and lower chamber boxes are placed in a vacuum state, and the molded film is heated. Next, the table is raised to raise the substrate 20 15. Next, only the inside of the upper chamber box 21 is opened to the atmosphere (FIG. 5(B)). At this time, the molded film is pressed 16 against the substrate side, and the molded film 10 and the substrate 20 are bonded together to be integrated (FIG. 5(C)). In this manner, a molded body 30 can be obtained.

In the first manufacturing method, the substrate 20 can be prepared in advance by any method. In the first manufacturing method, the material of the substrate 20 is not particularly limited, and may be made of resin or metal. Examples of materials for the substrate 20 in the first manufacturing method include thermoplastic resins such as polycarbonate, polymethyl methacrylate, polyethylene terephthalate, polybutylene terephthalate, polystyrene, polyamide, polyethersulfone, polyphenylene sulfide, polyvinyl chloride, polyethylene, polypropylene, cycloolefin polymer, ABS (acrylonitrile-butadiene-styrene copolymer resin), modified polyphenylene ether, and polymer alloys consisting of two or more of these resins, metals such as stainless steel, copper, and aluminum, and other glass and ceramics can also be used.

Note that in this first manufacturing method, the frictional stress with the substrate plastic at high temperatures in the aforementioned integration process with the substrate is due to the frictional stress between the conductive circuit of the molded film and the substrate at high temperatures when the molded film in FIG. 5(C) is pressed 16 against the substrate side and the molded film 10 and substrate 20 are bonded together to be integrated. In other words, in this first manufacturing method, the conductive layer is simultaneously subjected to a load due to tensile stress during molding and frictional stress with the substrate plastic at high temperatures.

<Second manufacturing method>
A second method for producing a molded article according to the present embodiment includes the steps of: printing the conductive resin composition for a molded film according to the present embodiment on a base film and drying the composition to produce a molded film;
forming the formed film into a predetermined shape;
placing the formed film in an injection mold;
and forming a substrate by injection molding and integrating the formed film with the substrate. Hereinafter, the second manufacturing method will be described with reference to Fig. 6. The second manufacturing method is sometimes called a film insert method.

Figure 6 is a schematic process diagram showing an example of the second manufacturing method of a molded body. In the second manufacturing method, the molded film 10 is molded into a predetermined shape in advance by a mold 11 (Figure 6 (A)). After being heated and softened, or while being softened, the molded film 10 is sucked into the mold by vacuum or pressed against the mold by compressed air, or both, and molded by the mold 11 (Figure 6 (B)). At this time, the molded film 10 may be molded so that the conductive layer faces either the substrate 20 side described later or the side opposite the substrate 20, and this is selected depending on the final use of the molded body. Next, the molded molded film 10 is placed in a mold 12 for injection molding (Figures 6 (C) to 6 (D)). Next, resin is injected 14 from an opening 13 to form the substrate 20, and the molded film 10 and the substrate 20 are integrated to obtain a molded body 30 (Figure 6 (E)).

In the second manufacturing method, the substrate 20 does not need to be prepared in advance, and the molding of the substrate and the integration with the molded film can be performed simultaneously. The material of the substrate 20 can be appropriately selected from known resins used for injection molding. Examples of the material of the substrate 20 in the second manufacturing method include the same thermoplastic resins as those listed as examples of the material of the substrate 20 in the first manufacturing method.

Note that in this second manufacturing method, the frictional stress with the base plastic at high temperatures in the aforementioned integration process with the substrate is due to the frictional stress that the conductive layer on the molded film receives when high-temperature molten resin is injected into the mold when resin is injected 14 from the opening 13 to form the substrate 20 and the molded film 10 and the substrate 20 are integrated in FIG. 6(E). In other words, in this second manufacturing method, the conductive layer is subjected to a load due to tensile stress during molding, and then in a separate process, it is subjected to frictional stress with the base plastic at high temperatures.

<Third manufacturing method>
The third method for producing a molded body according to the present embodiment includes the steps of: printing the conductive resin composition for molded films according to the present embodiment on a base film by screen printing; and drying the composition to produce a molded film.
placing the formed film in an injection mold;
The method includes a step of molding a substrate by injection molding and transferring the conductive layer in the molded film to the substrate side.
The following description will be given with reference to Fig. 7. The third manufacturing method is sometimes called an in-mold transfer method.

Figure 7 is a schematic process diagram showing an example of the third manufacturing method of a molded body. In the third manufacturing method, a molded film 10 having peelability is selected as a base film and used. The molded film 10 is placed in an injection molding die 12 so that the conductive layer faces the substrate 20 side described later (Figure 7 (A)). Next, resin is injected 14 from an opening 13 to form the substrate 20, and the molded film 10 and substrate 20 are in close contact with each other, at least the conductive layer is transferred to the substrate 20 side (Figure 7 (B)), and a molded body 30 is obtained (Figure 7 (C)). In addition, if the molded film 10 has a decorative layer, the decorative layer and the conductive layer are transferred.

In the third manufacturing method, since there is no need to cut the base film, a long base film can be arranged as shown in the example of Figure 7. The material of the substrate 20 can be appropriately selected from known resins used for injection molding. Examples of materials for the substrate 20 in the third manufacturing method include the same thermoplastic resins as those listed as examples of materials for the substrate 20 in the first manufacturing method.

In addition, in this third manufacturing method, the frictional stress with the base plastic at high temperatures in the aforementioned integration process with the substrate is due to the frictional stress that the conductive layer on the molded film receives when high-temperature molten resin is injected into the mold when resin is injected 14 from the opening 13 to form the substrate 20 in FIG. 7(C) and the molded film 10 and substrate 20 are brought into close contact with each other. In other words, in this third manufacturing method, the conductive layer is simultaneously subjected to a load due to tensile stress during molding and frictional stress with the base plastic at high temperatures.

The molded article obtained in this way makes it possible to mount circuits, touch sensors, and various electronic components on the plastic housings of home appliances, automobile parts, robots, drones, etc. It is also extremely useful for making electronic devices lighter, thinner, shorter, and smaller, improving design freedom, and increasing the functionality of these devices.

The present invention will be described in more detail below with reference to examples, but the following examples are not intended to limit the present invention in any way. In the examples, "parts" means "parts by mass" and "%" means "% by mass".
The weight average molecular weight in the examples is a polystyrene-equivalent molecular weight measured using a GPC (gel permeation chromatography) "HLC-8320" manufactured by Tosoh Corporation.

In the examples, the "functional group value" is calculated based on the molecular weight per functional group of each raw material (this is referred to as the functional group equivalent) and is expressed as the amount of functional groups per 1 g of raw material converted into an equimolar amount of potassium hydroxide (mg) using the following formula:
(Functional group value) [mg KOH/g] = (56.1 x 1000) / (functional group equivalent)
The above-mentioned functional group value is a general term for an amount expressed, for example, as an acid value when the functional group is a carboxyl group, a hydroxyl value when the functional group is a hydroxyl group, or an amine value when the functional group is an amino group. When comparing the functional group ratios of substances having different functional groups, those having the same value of the above-mentioned functional group value can be considered to have the same molar amount of functional groups.

When titration with potassium hydroxide is used to quantify the functional groups such as carboxyl groups and hydroxyl groups, the functional group values (acid value and hydroxyl value) can be directly determined from an appropriate amount of potassium hydroxide used for neutralization using a known and commonly used measuring method specified in, for example, JIS K 0070, and can be treated in the same way as the values calculated by the above formula.
In addition, even when the titration with potassium hydroxide is not used to determine the functional group value, such as isocyanate groups, the functional group value can be calculated in terms of potassium hydroxide for convenience by using the functional group equivalent weight derived from each measured value representing the amount of functional group and the above calculation formula. A specific calculation example is shown below.

Calculation Example 1: Calculation is performed for trifunctional isocyanate compound "X" having an isocyanate amount of 23% measured by the method specified in JIS K 6806 (a method in which an isocyanate group is reacted with n-dibutylamine and the remaining n-dibutylamine is titrated with an aqueous hydrochloric acid solution) as a compound having an isocyanate group. The functional group equivalent of trifunctional isocyanate compound "X" is derived as follows from the above isocyanate amount (%) and the molecular weight of the isocyanate group (NCO = 44 g/mol).
(functional group equivalent of "X") = 1/(0.23/44) = 191.3
From the functional group equivalent of this trifunctional isocyanate compound "X" and the above-mentioned formula for calculating the functional group value, the functional group value of the trifunctional isocyanate compound "X" can be calculated as follows.
(Functional value of trifunctional isocyanate compound "X") [mg KOH/g]
=(56.1×1000)/191.3=293.3

Synthesis Example 1: Synthesis of Resin (A-1) Synthesis of non-cyclic urethane A reaction apparatus equipped with a stirrer, a thermometer, a reflux condenser, and a nitrogen gas inlet tube was charged with 104.0 parts of polytetramethylene glycol ("PTMG650" manufactured by Mitsubishi Chemical Corporation), 4.2 parts of neopentyl glycol, 31.1 parts of hexamethylene diisocyanate, and 37.4 parts of toluene, and reacted for 3 hours at 90 ° C. under a nitrogen stream, and then cooled to stop the reaction. The mixture was then transferred to a pallet with a fluorine-treated surface and dried in a hot air drying oven at 120 ° C. for 5 hours and then vacuum dried for 24 hours to obtain a solid urethane resin (A-1) having a weight average molecular weight of 20,000, a glass transition point of -5 ° C., and no cyclic structure in the main chain of a hydroxyl group (functional group value 9 mg KOH / g).

<Synthesis Example 2: Synthesis of Resin (A-2)>
A reactor equipped with a stirrer, a thermometer, a rectifying tube, a nitrogen gas inlet tube, and a pressure reducing device was charged with 38.3 parts of dimethyl 1,4-cyclohexanedicarboxylate, 7.6 parts of propylene glycol, 10.4 parts of neopentyl glycol, and 0.03 parts of tetrabutyl titanate, and gradually heated to 180°C while stirring under a nitrogen stream, and an ester exchange reaction was carried out at 180°C for 3 hours, the acid value was measured, and when it became 15 or less, the pressure in the reactor was gradually reduced to 1 to 2 Torr, and when it reached a predetermined viscosity, the reaction was stopped and the mixture was removed, transferred to a fluorine-treated pallet, and cooled to obtain a solid polyester resin (A-2) having a weight average molecular weight of 34,000, a glass transition point of 58°C, a hydroxyl group (functional group value 7 mgKOH/g), and an alicyclic structure in the main chain.

Synthesis Example 3: Synthesis of Resin (A-3)
A reactor equipped with a stirrer, a thermometer, a rectifying tube, a nitrogen gas inlet tube, and a pressure reducing device was charged with 38.1 parts of dimethyl isophthalate, 7.6 parts of propylene glycol, 10.4 parts of neopentyl glycol, and 0.03 parts of tetrabutyl titanate, and gradually heated to 180 ° C. while stirring under a nitrogen stream, and an ester exchange reaction was carried out at 180 ° C. for 3 hours, the acid value was measured, and when it became 15 or less, the pressure in the reactor was gradually reduced to 1 to 2 torr, and when it reached a predetermined viscosity, the reaction was stopped and the mixture was removed, and then transferred to a fluorine-treated pallet and cooled to obtain a polyester resin (A-3) having a weight average molecular weight of 34,000, a glass transition point of 58 ° C., a hydroxyl group (functional group value 7 mg KOH / g), and an aromatic ring structure and an ester bond in the main chain.

<Synthesis Example 4: Synthesis of Resin (A-4)>
In a reaction apparatus equipped with a stirrer, a thermometer, a reflux condenser, and a nitrogen gas inlet tube, 170.0 parts of a polyester polyol obtained from isophthalic acid and 3-methyl-1,5 pentanediol (Kuraray Co., Ltd.'s "Kuraray Polyol P-1030"), 40.0 parts of isophorone diisocyanate, and 50.0 parts of toluene were charged and reacted for 3 hours at 90 ° C. under a nitrogen gas flow, and then 3.4 parts of isophorone diamine was added and reacted for another 2 hours at 90 ° C., and then cooled to stop the reaction. Finally, after removing the mixture, it was transferred to a pallet with a fluorine-treated surface and dried in a hot air drying oven at 120 ° C. for 5 hours and then vacuum dried for 24 hours to obtain a solid urethane resin (A-4) having a weight average molecular weight of 45,000, a glass transition point of 25 ° C., an amino group (functional value 3 mg KOH / g), and an aromatic ring structure and an ester bond in the main chain.

<Resins (A-5) to (A-6)>
The following resins were used as resins (A-5) to (A-6).
Resin (A-5): Phenoxy resin manufactured by Mitsubishi Chemical Corporation, jER-4275, weight average molecular weight 59,000, glass transition point 73° C., having an aromatic ring as a cyclic structure in the main chain.
Resin (A-6): Cellulose ester resin manufactured by Eastman Chemical Company, CAB381-0.1, weight average molecular weight 50,000, having a heterocyclic structure as a cyclic structure in the main chain.

<Resins (A-7) to (A-10)>
The following resins were used as resins (A-7) to (A-10).
Resin (A-7): Acrylic resin manufactured by Mitsubishi Chemical Corporation, Dianale BR-1122, weight average molecular weight 180,000, glass transition point 20°C.
Resin (A-8): Phenoxy resin manufactured by Gabriel Phenoxies, PKHJ, weight average molecular weight 57,000, glass transition point 98° C., containing two or more hydroxyl groups (functional group value 190 mg KOH/g) per molecule.
Resin (A-9): Polyester resin manufactured by Unitika Ltd., Elitel UE-3500, weight average molecular weight 56,000, glass transition point 15° C., containing two or more hydroxyl groups (functional value 4 mg KOH/g) per molecule.

Synthesis Example 5: Synthesis of Resin (A-10)
In a reaction apparatus equipped with a stirrer, a thermometer, a reflux condenser, and a nitrogen gas inlet tube, 127.0 parts of a polyester polyol obtained from isophthalic acid and 3-methyl-1,5 pentanediol (Kuraray Co., Ltd.'s "Kuraray Polyol P-2030"), 19.0 parts of isophorone diisocyanate, and 36.5 parts of toluene were charged and reacted at 90 ° C. for 3 hours under a nitrogen stream, and then 5.5 parts of isophorone diamine was added and reacted at 90 ° C. for another 2 hours, after which the reaction was stopped by cooling, and finally the mixture was taken out and transferred to a fluorine-treated surface pallet and dried in a hot air drying oven at 120 ° C. for 5 hours and then vacuum dried for 24 hours to obtain a solid urethane resin (A-10) having a weight average molecular weight of 35,000, a glass transition point of 5 ° C., and an amino group (functional group value 4 mg KOH / g).

The following were used as the solvent, crosslinking agent, conductive particles and other components:

<Solvents (B'-1) to (B'-10)>
Solvent (B'-1): Dipropylene glycol monomethyl ether acetate, boiling point 213°C, δd = 16.3, δp = 4.9, δh = 8.0 (satisfies condition (2-2))
Solvent (B'-2): terpinyl acetate, boiling point 220°C, δd = 16.3, δp = 3.6, δh = 4.8 (satisfies condition (2-3))
Solvent (B'-3): diethylene glycol dibutyl ether, boiling point 256°C, δd = 15.8, δp = 4.4, δh = 4.7 (satisfies condition (2-2))
Solvent (B'-4): triethylene glycol dimethyl ether, boiling point 220°C, δd = 15.8, δp = 2.3, δh = 8.2 (satisfies condition (2-3))
Solvent (B'-5): diethylene glycol monobutyl ether, boiling point 231°C, δd = 16.0, δp = 7.0, δh = 10.6 (satisfies condition (2-1))
Solvent (B'-6): triethylene glycol monomethyl ether, boiling point 249°C, δd = 16.2, δp = 7.6, δh = 12.5 (satisfies condition (2-1))
Solvent (B'-7): benzyl alcohol, boiling point 205°C, δd = 18.4, δp = 6.3, δh = 13.7 (satisfies condition (2-1))
Solvent (B'-8): phenoxyethanol, boiling point 247°C, δd = 17.8, δp = 5.7, δh = 14.3 (satisfies condition (2-1))
Solvent (B'-9): diethylene glycol monomethyl ether, boiling point 194°C, δd = 16.2, δp = 7.8, δh = 12.6 (satisfies condition (2-1))
Solvent (B'-10): Diethylene glycol monoethyl ether, boiling point 202°C, δd = 16.1, δp = 9.2, δh = 12.2 (satisfies condition (2-1))

<Solvents (B11) to (B14)>
Solvent (B11): diethylene glycol monoethyl ether acetate, boiling point 217° C., δd=16.2, δp=5.1, δh=9.2
Solvent (B12): diethylene glycol monobutyl ether acetate, boiling point 239° C., δd=16.0, δp=4.1, δh=8.2
Solvent (B13): Tetralin, boiling point 207° C., δd=19.6, δp=2.0, δh=2.9
Solvent (B14): 2-methoxypropanol, boiling point: 120°C, δd = 15.6, δp = 6.3, δh = 11.6

<Conductive fine particles (C-1) to (C-4)>
Conductive fine particles (C-1): Flake-shaped silver powder, average particle size 5.2 μm, manufactured by Fukuda Metal Foil and Powder Co., Ltd.
・Conductive fine particles (C-2): Manufactured by Fukuda Metal Foil and Powder Co., Ltd., chain agglomerated silver powder, average particle size 1.5 μm
Conductive fine particles (C-3): Dowa Electronics Co., Ltd., flake-shaped silver-coated copper powder, silver coating amount 10%, average particle size 4.0 μm
Conductive fine particles (C-4): Manufactured by Ito Graphite Co., Ltd., flake graphite, average particle size 15 μm

<Crosslinking Agent (D)>
Crosslinking agent (D-1):
Blocked isocyanate solution manufactured by Baxeneden Chemicals, Trixene BI7963, containing three isocyanate groups blocked with ethyl methyl ketone oxime per molecule (functionality 168 mg KOH/g), non-volatile content 70% (solvent (E3): 2-methoxypropanol)

<Other Components (E-1) and (E-2)>
Other components (E-1): Defoamer, BYK-1790, solids content 100%, manufactured by BYK-Chemie
Other components (E-2): Daiichi Kogyo Seiyaku Co., Ltd., anionic lubricant, potassium soap HY, solids content 100%

<Production Example 1: Preparation of conductive resin composition for molded film (F-1)>
20.0 parts of resin (A-1) was dissolved in 30.0 parts of solvent (B-1), and 80.0 parts of conductive fine particles (D-1) were stirred and mixed. The mixture was kneaded with a three-roll mill (manufactured by Kodaira Seisakusho Co., Ltd.), and then stirred and mixed uniformly with a planetary mixer to obtain a conductive resin composition for molded films (F-1).

<Production Examples 2 to 18: Preparation of Conductive Resin Compositions (F-2) to (F-18) for Molded Films>
Conductive resin compositions (F-2) to (F-18) for molded films were obtained in the same manner as in Production Example 1, except that the types and amounts of the resin, solvent, conductive fine particles, and crosslinking agent (when a crosslinking agent or other component (E-1) was used, the crosslinking agent and other component (E-1) were added immediately before uniform stirring and mixing with a planetary mixer) were changed as shown in Table 1.

<Production Example 19: Preparation of insulating resin composition (G-1) for molded film>
20.0 parts of resin (A-7) was dissolved in 30.0 parts of solvent (B'-1), 0.2 parts by weight of antifoaming agent (E-1) was added, and the mixture was stirred and mixed uniformly using a planetary mixer to obtain an insulating resin composition for molded films (G-1).

<Production Examples 20 to 38: Preparation of insulating resin compositions (G-2) to (G-20) for molded films>
In Production Example 19, the types and amounts of the resin, solvent, and crosslinking agent were changed as shown in Table 2, and the same procedures were followed as in Production Example 19 to obtain insulating resin compositions (G-2) to (G20) for molded films.

<Production Example 39: Preparation of Decorative Ink (H-1)>
250 parts of a resin solution consisting of 100 parts of resin (A-3) and 150 parts of solvent (B'-1) was prepared, and 20 parts of phthalocyanine blue pigment (Leonol Blue FG7351, manufactured by Toyo Color Co., Ltd.) and 10 parts by mass of titanium oxide pigment (TIPAQUE CR-93, manufactured by Ishihara Sangyo Kaisha, Ltd.) were stirred and mixed therein, and the mixture was kneaded with a three-roll mill (manufactured by Kodaira Seisakusho Co., Ltd.). After that, 5 parts of an isocyanate crosslinking agent (Desmodur N3300, manufactured by Sumika Covestro Urethane Co., Ltd., non-volatile content 100%) and 0.1 parts of an antifoaming agent (E-1) were added and stirred and mixed uniformly to obtain a decorative ink (H-1).

The numerical values for each material in Tables 1 to 9 are all in parts by weight.

<Examples 1 to 78 and Comparative Examples 1 to 10>
Conductive resin compositions for molded films (F-1) to (F-18) were each printed on a polycarbonate (PC) base film (Teijin, Panlite 2151, thickness 300 μm) using a screen printer (Minoscreen, Minomat SR5575 semi-automatic screen printer). Then, by heating in a hot air drying oven at 120° C. for 30 minutes, molded films were obtained each having a conductive layer having (1) a square solid pattern with a width of 70 mm, a length of 120 mm, and a thickness of 10 μm, (2) a linear pattern with a line width of 2 mm, a length of 60 mm, and a thickness of 10 μm, and (3) a comb-shaped wiring pattern with an opposing line length of 50 mm and L/S=100 μm/100 μm, with 10 positive and negative lines. For the square solid pattern (1) at this stage, the volume resistivity of the conductive layer was measured using a resistivity meter (Loresta GX MCP-T700, manufactured by Mitsubishi Chemical Analytical Co., Ltd.).
Further, on the surface of the conductive pattern of the molded film having the conductive layer, the insulating resin compositions for molded film (G-1) to (G-20) were printed by the screen printer in layers, respectively: (1) for the square solid conductive pattern, so as to cover the entire conductive pattern with a width of 90 mm, a length of 140 mm, and a thickness of 15 μm; (2) for the linear conductive pattern, so as to expose both ends of 10 mm in the length direction of the conductive pattern and cover the other parts with a width of 10 mm, a length of 40 mm, and a thickness of 15 μm; and (3) for the comb-shaped wiring pattern, so as to cover a part of the comb-shaped opposing pattern part with a width of 6 mm, a length of 40 mm, and a thickness of 15 μm. Next, by heating in a hot air drying oven at 120° C. for 30 minutes, a molded film having the patterned conductive layer and an insulating layer laminated so as to cover a part or all of the conductive layer was obtained. At this time, the combinations of the conductive resin composition and the insulating resin composition were as shown in Tables 3 to 6, and molded films were prepared. At this stage (1), the insulating layer of the rectangular solid pattern at the end portion not overlapping with the conductive layer was measured for volume resistivity using a resistivity meter (Hiresta UX MCP-HT800, manufactured by Mitsubishi Chemical Analytical Co., Ltd.).

<Examples 79 to 82>
The decorative ink (H-1) was applied to a polycarbonate base film (Teijin Limited, Panlite 2151, thickness 300 μm) using a blade coater so that the dry film thickness was 2 μm, and the film was heated at 120° C. for 30 minutes to form a decorative layer.
Next, in Examples 2, 22, 56, and 72, a molded film was obtained in which a polycarbonate base film, a decorative ink layer, a conductive layer, and an insulating layer were laminated in that order in the same manner as in Examples 2, 22, 56, and 72, except that the base film with the decorative layer was used instead of the polycarbonate base film, and a conductive layer and an insulating layer were formed on the decorative layer.

<Examples 83 to 86>
In the above-mentioned Examples 2, 22, 56, and 72, a polycarbonate resin/acrylic resin two-layer co-extrusion base film (manufactured by Sumitomo Chemical Co., Ltd., Technoloy C001, thickness 125 μm) was used instead of the polycarbonate base film, and a conductive resin composition for molded films and an insulating resin composition were printed on the polycarbonate resin side. Except for this, molded films were obtained in the same manner as in the above-mentioned Examples 2, 22, 56, and 72.

<Examples 87 to 90>
In the above-mentioned Examples 2, 22, 56, and 72, molded films were obtained in the same manner as in the above-mentioned Examples 2, 22, 56, and 72, except that an acrylic resin base film (Technoloy S001G, manufactured by Sumitomo Chemical Co., Ltd., thickness 250 μm) (300 mm x 210 mm) was used instead of the polycarbonate base film, and the drying conditions in the hot air drying oven were 80° C. and 30 minutes.

<Examples 91 to 94>
In the above-mentioned Examples 2, 22, 56, and 72, a polyethylene terephthalate resin base film (A-PET film manufactured by RP Toho Plastics, NOACRYSTAL-V, thickness 300 μm) (300 mm × 210 mm) was used instead of the polycarbonate base film, and the drying conditions in the hot air drying oven were 80 ° C. and 30 minutes. Except for this, a molded film was obtained in the same manner as in the above-mentioned Examples 2, 22, 56, and 72.

<Examples 95 to 98>
In the above-mentioned Examples 2, 22, 56, and 72, a polypropylene resin base film (Idemitsu Unitech Co., Ltd., Pure Thermo AG-306, thickness 200 μm) (300 mm x 210 mm) was used instead of the polycarbonate base film, and the drying conditions in the hot air drying oven were 80° C. and 30 minutes. Except for this, a molded film was obtained in the same manner as in the above-mentioned Examples 2, 22, 56, and 72.

<Example 99>
A conductive resin composition for films and an insulating resin composition were printed on the unprinted back surface of the molded film obtained in Example 1 in a position overlapping the conductive pattern and insulating pattern of Example 1 on the front and back, thereby forming a second conductive layer and a second insulating layer laminated so as to cover part of it. A molded film was obtained in the same manner as in Example 1, except that the second conductive layer and the second insulating layer laminated so as to cover part or all of the second conductive layer were formed on both sides of the base film.

<Example 100>
Printing and drying were further performed on the insulating pattern of the molded film obtained in Example 1 at a position 5 mm away from the end spacing in the width direction from the conductive pattern of Example 1 in the same manner as the process for forming the conductive pattern of Example 1, and a second insulating layer pattern was printed at a position overlapping the insulating pattern of Example 1. As a result, a molded film was obtained having, in this order, a first conductive layer on one side of the base film, a first insulating layer laminated so as to cover part of it, a second conductive layer, and a second insulating layer laminated so as to cover part of it.

<Comparative Examples 1 and 2>
A molded film was obtained in the same manner as in Examples 1 and 3, except that no insulating layer was formed.

[(1) Wiring Resistance Evaluation]
The molded films of Examples 1 to 100 and Comparative Examples 1 to 10 were cut out to a length of 70 mm and a width of 10 mm so that the 2 mm x 60 mm linear conductive layer pattern formed on each film was in the center, and used as measurement coupons. On the surface of each measurement coupon opposite the conductive layer, two lines perpendicular to the conductive layer were drawn at 4 cm intervals from the longitudinal end with a permanent marker. The resistance values of positions 4 cm apart according to these marks were measured using a tester, and these were taken as wiring resistance (Ω). The results are shown in Tables 3 to 9.

[(2) Hot Stretching Evaluation 1]
The measurement coupons of Examples 1 to 86, 99 to 100, and Comparative Examples 1 to 10 were stretched in the longitudinal direction at a stretching speed of 10 mm/min to an elongation rate of 50% in a heating oven at 160°C. After removing from the oven and cooling, the presence or absence of disconnection was evaluated using an optical microscope. In addition, the wiring resistance (Ω) was measured at positions corresponding to 4 cm intervals based on the original mark in the same manner as in the measurement of the wiring resistance described above, and the wiring resistance after stretching/wiring resistance before stretching was defined as the resistance variation rate (times) during hot stretching, and each was evaluated according to the following criteria. The results are shown in Tables 3 to 9.
(Whether or not there is a break in the wire)
A: No breaks were observed.
B: 1 to 2 minor cracks were observed. C: Severe disconnection or peeling of the conductive coating was observed. (Resistance variation rate during hot stretching)
A: 5 times or more but less than 10 times B: 10 times or more but less than 50 times C: 50 times or more

The elongation rate is a value calculated as follows.
(Elongation rate) [%] = {(length after stretching - length before stretching) / (length before stretching)} x 100

[(3) Hot Stretching Evaluation 2]
The heat stretching evaluation was performed in the same manner as in the heat stretching evaluation 1, except that the elongation rate was changed to 100%, and the evaluation was performed according to the following criteria. The results are shown in Tables 3 to 9.
(Whether or not there is a break in the wire)
A: No breaks were observed.
B: 1 to 2 minor cracks were observed. C: Severe disconnection or peeling of the conductive coating was observed. (Resistance variation rate during hot stretching)
A: 10 times or more but less than 50 times B: 50 times or more but less than 200 times C: 200 times or more

[(4) Hot Stretching Evaluation 3]
The measurement coupons of Examples 87 to 98 were stretched in the longitudinal direction in a heating oven at 120° C. at a pulling speed of 10 mm/min to an elongation rate of 50%. After removing from the oven and cooling, the presence or absence of disconnection was evaluated using an optical microscope. In addition, the wiring resistance (Ω) was measured at positions corresponding to 4 mm intervals based on the original mark in the same manner as in the measurement of the wiring resistance described above, and the wiring resistance after stretching/wiring resistance before stretching was defined as the resistance variation rate (times) during thermal stretching, and each was evaluated according to the following criteria. The results are shown in Table 6.
(Whether or not there is a break in the wire)
A: No breaks were observed.
B: 1 to 2 minor cracks were observed. C: Severe disconnection or peeling of the conductive coating was observed. (Resistance variation rate during hot stretching)
A: 5 times or more but less than 10 times B: 10 times or more but less than 50 times C: 50 times or more

[(5) Hot Stretching Evaluation 4]
The heat stretching evaluation was performed in the same manner as in the heat stretching evaluation 3, except that the elongation rate was changed to 100%, and the evaluation was performed according to the following criteria. The results are shown in Table 6.
(Whether or not there is a break in the wire)
A: No breaks were observed.
B: 1 to 2 minor cracks were observed. C: Severe disconnection or peeling of the conductive coating was observed. (Resistance variation rate during hot stretching)
A: 10 times or more but less than 50 times B: 50 times or more but less than 200 times C: 200 times or more

[(6) Process resistance evaluation 1 during production of molded body by overlay molding]
A hemispherical ABS resin molded product with a radius of 4 cm was placed facing the conductor side so as to overlap the position of the 2 mm x 60 mm linear pattern of the molded film of Examples 1 to 86, 99 to 100, and Comparative Examples 1 to 10, and overlay molding was performed at a set temperature of 160 ° C. using a TOM molding machine (manufactured by Fuse Vacuum Co., Ltd.) to obtain a molded product in which the molded film molded into a hemispherical shape and the ABS resin molded product were integrated. The scraping and resistance variation rate of the linear pattern wiring of this molded product were confirmed. The resistance variation rate was evaluated by measuring the wiring resistance (Ω) at a position corresponding to a 6 cm interval based on the original mark, and the wiring resistance after stretching/wiring resistance before stretching was defined as the resistance variation rate (times) during hot stretching, and each was evaluated according to the following criteria. The results are shown in Tables 3 to 9.
(Disconnection and resistance fluctuation rate)
A: No scraping of the wiring was observed, and the resistance fluctuation rate was 5 times or more and less than 30 times. B: One or two places where chipping of the ends due to scraping of the wiring was observed, or the resistance fluctuation rate was 30 times or more and less than 500 times. C: One or more places where breaks due to scraping of the wiring were observed.

[(7) Process resistance evaluation 2 during production of molded body by overlay molding]
Except for using the 2 mm x 60 mm linear patterns of the molded films of Examples 87 to 98 and carrying out overlay molding at 120°C, molded bodies were obtained in the same manner as in Evaluation 1 of process resistance during production of molded bodies by overlay molding, and the scraping of the linear pattern wiring during overlay molding and the resistance variation rate were evaluated. The results are shown in Table 7.

[(8) Process resistance evaluation 1 during production of molded body by film insert molding]
A block-shaped metal mold having a hemispherical depression with a radius of 4 cm in the center was aligned with the conductive layer and insulating layer sides so as to overlap the position of the 2 mm x 60 mm linear pattern of the molded films of Examples 1 to 86, 99 to 100, and Comparative Examples 1 to 10 above, and overlay molding was performed at a set temperature of 160°C using a TOM molding machine (manufactured by Fuse Vacuum Co., Ltd.) to obtain a moldable film molded into a hemispherical shape and having a patterned conductor on the inside.
Next, the molded film molded into a hemispherical shape was set in an injection molding machine (IS170 (i5), manufactured by Toshiba Machine Co., Ltd.) equipped with a valve gate type in-mold molding test mold, and a PC/ABS resin (LUPOYPC/ABSHI5002, manufactured by LG Chemical Co., Ltd.) was injection molded to obtain a molded body integrated with the molded film with a patterned conductor (injection conditions: screw diameter 40 mm, cylinder temperature 260 ° C., mold temperature (fixed side, movable side) 80 ° C., injection pressure 180 MPa, holding pressure 120 MPa, injection speed 60 mm/sec (28%), injection time 4 seconds, cooling time 20 seconds). Washout due to injection of molten resin of the linear pattern of this molded body (deformation or disconnection of the wiring pattern due to the temperature and injection pressure of the molten thermoplastic resin) and resistance variation rate were confirmed. The resistance variation rate was evaluated by measuring the wiring resistance (Ω) at positions corresponding to 6 cm intervals based on the original mark, and the wiring resistance after stretching/wiring resistance before stretching was defined as the resistance variation rate (times) during thermal stretching. The results are shown in Tables 3 to 9.
(Presence or absence of disconnection and resistance fluctuation rate)
A: No washout of the wiring was observed at all, and the resistance fluctuation rate was 10 times or more but less than 50 times. B: Wiring distortion due to mild washout was observed, or the resistance fluctuation rate was 50 times or more but less than 500 times. C: One or more breaks due to washout of the wiring were observed.

[(9) Process resistance evaluation 2 during production of molded body by film insert molding]
Except for using the 2 mm x 60 mm linear patterns of the molded films of Examples 87 to 98 and performing overlay molding at 120 ° C., molded bodies were obtained in the same manner as in the process resistance evaluation 1 during the production of molded bodies by film insert molding, and the degree of washout and resistance variation rate due to molten resin injection of the linear pattern during film insert molding were evaluated. The results are shown in Table 7.

[(10) Evaluation of ion migration resistance of molded body by film insert molding]
Using the molded films having the comb-shaped wiring patterns and insulating layers of the molded films of Examples 1 to 100 and Comparative Examples 1 to 10, overlay molding was performed by aligning the mold so that the position of the comb-shaped wiring pattern and the center position overlapped. Molded bodies were obtained in the same manner as in the process resistance evaluations 1 and 2 when manufacturing molded bodies by film insert molding.
The exposed wiring portions of the positive and negative electrodes of the comb-shaped wiring of each of the above molded bodies were connected to wiring with alligator clips, and the insulation resistance value between the comb-shaped wiring terminals after 1000 hours under conditions of 5 V application and 85°C and 85% RH was confirmed using an IMV migration tester insulation deterioration evaluation tester "MIG-8600B," and each was evaluated according to the following criteria. The results are shown in Tables 3 to 9.
(Presence or absence of short circuits due to ion migration and insulation resistivity)
A: The insulation resistance fluctuation rate is less than ±25% of the initial value. B: The insulation resistance fluctuation rate is between ±25% and ±100% of the initial value. C: The insulation resistance fluctuation rate is more than ±100% of the initial value or there is a leak touch (a history of short circuits between electrodes).

[Summary of results]
In Comparative Examples 1 and 2, in which no insulating layer was formed on the conductive layer, the molded body had poor resistance to ion migration between the comb-shaped electrodes, and was prone to short circuits over time, making it unsuitable for use as a three-dimensional wiring circuit. This is thought to be due to the fact that the adhesion between the base film and injection molding resin of the molded body is insufficient, which causes the penetration of moisture from this interface to promote ionization and the mechanical deterioration of the conductive pattern due to thermal expansion and contraction.
In Comparative Examples 3 and 7, although an insulating layer was formed, the volume resistivity was low at less than 10 ¹⁰ Ω·cm, so the ion migration resistance between the comb electrodes of the molded body was also at a level that could not withstand practical use. Furthermore, in Comparative Examples 4 to 6 and 8 to 10, although an insulating layer was formed, a solvent that satisfied the specific HSP conditions was not used in the insulating composition for forming the insulating layer, so the ion migration resistance between the comb electrodes of the molded body was also at a level that could not withstand practical use.

On the other hand, from the results of Examples 1 to 100, the conductive layer and molded film having the insulating layer of this embodiment, in which a solvent satisfying a specific HSP condition is used in the insulating composition for forming the insulating layer, are not only less likely to break due to molten resin injection during overlay molding and film insert molding, but also suppress breakage of the conductive layer pattern during heat stretching of the molded film, and excellent ion migration resistance based on the insulating performance of the insulating layer itself and high adhesion to the base film and injection molding resin was achieved. In particular, the molded films of Examples 2 to 78, 80 to 82, 84 to 86, 88 to 90, 92 to 94, and 96 to 98, which are resins having a cyclic structure in the main chain structure of the conductive resin composition for forming the conductive layer, were excellent in suppressing the increase in the resistance value of the conductive layer pattern due to the stretching of the molded film during molding. In addition, the above-mentioned balance of properties was particularly excellent when the conductive resin composition for forming the conductive layer had an aromatic ring structure or an aromatic ester structure derived from an aromatic carboxylic acid in the main chain structure. Although some aspects of the mechanism by which such properties are expressed are unclear, the conductive properties of the conductive layer pattern improved when the molded film was stretched during molding are thought to be due to the fact that the solvent that satisfies the specific HSP conditions contained in the insulating composition for forming the insulating layer of the present invention has moderate wettability into the conductive layer but is unlikely to remain, so that the interface between the conductive layer and the insulating layer is compatible with each other but does not accumulate damage to the conductive layer. As a result, stress and localized deformation do not concentrate on the conductive layer when the molded film is thermoformed under high temperature conditions, and defects such as voids are unlikely to occur at the interface between the conductive layer and the insulating layer, which is thought to suppress deterioration of the wiring.

Furthermore, due to the above-mentioned characteristics, a molded film having a conductive layer of the conductive resin composition of the present invention was able to produce an excellent molded body with integrated wiring, even if the substrate surface was a three-dimensional shape that was not flat. As for the ion migration resistance of this molded body, the generation of microcracks in the conductive layer pattern during molding of the molded film of the present invention and the associated generation of voids near the surface of the conductive layer were suppressed, and it is believed that this resulted in improved ion migration resistance.

In this way, the molded films and wiring-integrated molded bodies using the conductive resin composition of this embodiment can be directly applied to plastic housings and three-dimensional parts for home appliances, automobile parts, robots, drones, etc., making it possible to fabricate lightweight, space-saving circuits, touch sensors, antennas, heating elements, electromagnetic shields, inductors (coils), resistors, and various electronic components without compromising design freedom. They are also extremely useful for making electronic devices lighter, thinner, shorter, and smaller, improving design freedom, and increasing functionality.

Reference Signs List 1 Base film 2 Conductive layer 3 Insulating layer 4 Electronic component 5 Pin 6 Decorative layer 7 Second conductive layer 8 Second insulating layer 10 Molded film 11 Mold 12 Injection mold 13 Opening 14 Injection 15 Rising 16 Pressurizing 17 Resin 20 Substrate 21 Upper chamber box 22 Lower chamber box 30 Molded body

Claims (10)

A method for producing a molded film for forming a printed conductive circuit covered with an insulating layer on a substrate surface having an uneven surface or a three-dimensional curved surface, comprising the steps of:
The molded film is a molded film having a conductive layer and an insulating layer on a base film,
the conductive layer is a cured product of a conductive resin composition containing a resin (A1), a solvent (B1), and conductive particles (C);
the insulating layer is a cured product of an insulating resin composition containing a resin (A2) and a solvent (B2), and the insulating layer has a volume resistivity of 1×10 ¹⁰ Ω·cm or more and less than 1×10 ¹⁷ Ω·cm;
the solvent (B2) contains a solvent (b2) which satisfies the following condition (1) and any one of conditions selected from the group consisting of conditions (2-1), (2-2), and (2-3),
the ratio of the solvent (b2) in the solvent (B2) is 20% by weight to 100% by weight,
the resin (A1) comprises an acrylic resin, a vinyl ether resin, a polyether resin, a polyester resin, a polyurethane resin, an epoxy resin, a phenoxy resin, a polycarbonate resin, a polyolefin resin, a styrene block copolymer resin, a polyamide resin, or a polyimide resin;
The resin (A1) is a resin having a cyclic structure in its main chain structure,
A method for producing a molded film, comprising the steps of obtaining a conductive layer using a conductive resin composition, and obtaining an insulating layer using an insulating resin composition.
(1) The boiling point is 180°C or more and less than 300°C. (2-1) The HSP (Hansen solubility parameter) is
14.0≦δd≦20.0 and 5.0≦δp≦10.0 and 9.5≦δh≦20.0
(2-2) HSP (Hansen solubility parameter) is
14.0≦δd≦19.0 and 4.0<δp≦5.0 and 0.0≦δh≦8.0
(2-3) HSP (Hansen solubility parameter) is
14.0≦δd≦19.0 and 0.0≦δp≦4.0 and 0.0≦δh≦9.0 The method for producing a molded film according to claim 1, wherein the base film is a film selected from the group consisting of polycarbonate, polymethyl methacrylate, polypropylene, and polyethylene terephthalate, or a laminate film thereof. The method for producing a molded film according to claim 1 or 2 , wherein the resin (A1) is a resin having an aromatic ring structure in its main chain structure. The method for producing a molded film according to any one of claims 1 to 3 , wherein the resin (A1) is a resin having an aromatic ester structure derived from an aromatic carboxylic acid in a main chain structure. The method for producing a molded film according to any one of claims 1 to 4 , wherein a conductive layer and an insulating layer are provided in this order on both sides of the base film. The method for producing a molded film according to any one of claims 1 to 5 , further comprising providing a second conductive layer and a second insulating layer in this order on the insulating layer. A method for producing a molded product in which a molded film molded into a predetermined shape is laminated on a substrate so that an insulating layer surface is in contact with a substrate surface, or a base film surface is in contact with a substrate surface, and a printed conductive circuit covered with an insulating layer is formed on a substrate surface having an uneven surface or a three-dimensional curved surface,
The molded film is a molded film having a conductive layer and an insulating layer on a base film,
the conductive layer is a cured product of a conductive resin composition containing a resin (A1), a solvent (B1), and conductive particles (C);
The insulating layer is a cured product of an insulating resin composition containing a resin (A2) and a solvent (B2), and the volume resistivity of the insulating layer is
1×10 ¹⁰ Ω·cm or more and less than 1×10 ¹⁷ Ω·cm;
the solvent (B2) contains a solvent (b2) which satisfies the following condition (1) and any one of conditions selected from the group consisting of conditions (2-1), (2-2), and (2-3),
the ratio of the solvent (b2) in the solvent (B2) is 20% by weight to 100% by weight,
the resin (A1) comprises an acrylic resin, a vinyl ether resin, a polyether resin, a polyester resin, a polyurethane resin, an epoxy resin, a phenoxy resin, a polycarbonate resin, a polyolefin resin, a styrene block copolymer resin, a polyamide resin, or a polyimide resin;
The resin (A1) is a resin having a cyclic structure in its main chain structure,
A step of obtaining a molded film, the step including a step of obtaining a conductive layer using a conductive resin composition and a step of obtaining an insulating layer using an insulating resin composition;
A step of laminating the molded film on a substrate to obtain a molded body;
A method for producing a molded body having the above structure .
(1) A boiling point of 180°C or higher but less than 300°C
(2-1) HSP (Hansen solubility parameter) is
14.0≦δd≦20.0 and 5.0≦δp≦10.0 and 9.5≦δh≦20.0
(2-2) HSP (Hansen solubility parameter) is
14.0≦δd≦19.0 and 4.0<δp≦5.0 and 0.0≦δh≦8.0
(2-3) HSP (Hansen solubility parameter) is
14.0≦δd≦19.0 and 0.0≦δp≦4.0 and 0.0≦δh≦9.0 A step of laminating the molded film on a substrate to obtain a molded body,
placing a formed film;
A step of integrating the molded film and the substrate by an overlay molding method;
The method for producing the molded article according to claim 7 , comprising: A step of laminating the molded film on a substrate to obtain a molded body,
forming the formed film into a predetermined shape;
placing the formed film in an injection mold;
A step of forming a substrate by injection molding and integrating the formed film with the substrate;
The method for producing the molded article according to claim 7 , comprising: A step of laminating the molded film on a substrate to obtain a molded body,
placing the formed film into an injection mold;
A step of molding a substrate by injection molding and transferring a conductive layer in the molded film to the substrate side;
The method for producing the molded article according to claim 7 , comprising: