TWI844723B - Shape transfer film - Google Patents

Abstract

The subject of the present invention is to provide a shape transfer film having a concave-convex shape, which can provide sufficient concealment to the transfer object by transferring the shape derived from the concave-convex shape to the transfer object, and can be easily peeled off from the transfer object when intending to peel it off. In terms of the solution, the shape transfer film has a concave-convex shape with an interface development area ratio Sdr of 1500~7000% and/or a core height difference Sk of 2.0~7.0μm on at least one side, which is used to transfer the shape derived from the concave-convex shape to the transfer object. The shape transfer film, for example, has a substrate layer and a resin layer disposed on one side of the substrate layer. In addition, the shape transfer film, for example, contains fillers, and the concave-convex shape is formed by making the fillers protrude more outward than the flat surface of the film.

Description

Shape transfer film

Field of the Invention The present invention relates to a shape transfer film. More specifically, the present invention relates to a shape transfer film for transferring a shape derived from a concave-convex shape of the shape transfer film to a transfer object.

Background technology In electronic devices such as mobile phones, video cameras, and laptop computers, printed wiring boards are widely used to integrate circuits into the mechanism. They are also used to connect the movable part of the print head and the control part. In these electronic devices, electromagnetic wave shielding measures must be taken, and shielded printed wiring boards with electromagnetic wave shielding measures are also beginning to be used in the printed wiring boards used in the devices.

An electromagnetic wave shielding film is used to shield a printed wiring board. For example, an electromagnetic wave shielding film used in conjunction with a printed wiring board has: a conductive adhesive layer; and a protective layer for protecting the conductive adhesive layer or a shielding layer such as a metal layer provided as needed.

In recent years, in a shielded printed wiring board, the protective layer constituting the outermost layer of the electromagnetic wave shielding film laminated on the printed wiring board is sometimes required to have a low surface glossiness for the purpose of concealing the circuit pattern. As an example of a protective layer with low surface glossiness, there can be exemplified a protective layer having a concave-convex shape on the surface. Such a protective layer can be produced, for example, as follows: a composition for forming a protective layer is poured and coated on the concave-convex surface of a transfer film (shape transfer film) having a concave-convex shape on the surface, and then the protective layer is formed by curing, thereby imparting (transferring) the shape of the concave-convex shape derived from the shape transfer film to the surface of the protective layer for matte processing.

As such a shape transfer film, for example, the one disclosed in Patent Document 1 is known.

Prior art documents Patent documents Patent document 1: Japanese Patent Publication No. 2017-71107

Summary of the invention Problems to be solved by the invention However, in the conventional shape transfer film having a concave-convex shape for the purpose of imparting concealing properties to the protective layer, when the shape transfer film is laminated with the protective layer, the anchoring effect derived from the concave-convex shape takes effect, so that when the shape transfer film is peeled off from the protective layer, it is difficult to peel off, or even when the shape transfer film can be peeled off, there is a problem that the protective layer is peeled off along with it. On the other hand, if the above-mentioned concavo-convex shape is made shallow, the anchoring effect can be weakened, and the shape transfer film can be easily peeled off from the state that it has been attached to the protective layer. However, since the concavo-convex shape formed on the protective layer will also become shallow, it is impossible to give the protective layer sufficient concealment.

The present invention is made in view of the above, and the purpose of the present invention is to provide a shape transfer film having a concave-convex shape. By transferring the shape derived from the concave-convex shape to the transfer object, sufficient concealment can be given to the transfer object, and it can be easily peeled off from the transfer object when it is intended to be peeled off.

Means for Solving the Problem The inventors have made careful studies to achieve the above-mentioned purpose and have found that if a shape transfer film having a specific concave-convex shape on its surface is used, the shape derived from the concave-convex shape can be transferred to the transfer object, thereby giving the transfer object sufficient concealment and making it easy to peel off the transfer object when it is intended. The present invention was completed based on these findings.

The present invention provides a shape transfer film, at least one side of which has a concave-convex shape with an interface development area ratio Sdr of 1500-7000%, for transferring a shape derived from the concave-convex shape to a transfer object.

The height difference Sk of the core of the above-mentioned concave-convex shape is preferably 2.0~7.0μm.

In addition, the present invention provides a shape transfer film having at least one surface thereof having a concave-convex shape with a core height difference Sk of 2.0-7.0 μm, for transferring a shape derived from the concave-convex shape to a transfer object.

The arithmetic mean height Sa of the above-mentioned concavo-convex shapes is preferably 1.0~2.0μm.

The root mean square height Sq of the above-mentioned concavo-convex shape is preferably 1.0~2.8μm.

The root mean square slope Sdq of the above-mentioned concave-convex shape should be 7~15.

The ratio of the interface development area ratio Sdr of the above-mentioned concavo-convex shape to the root mean square slope Sdq [Sdr/Sdq] is preferably 200~500.

The shape transfer film preferably includes a base layer and a resin layer disposed on one surface of the base layer, and the side surface of the resin layer has the concavo-convex shape.

The shape transfer film preferably includes a filler, and the concavo-convex shape is formed by making the filler protrude outwards more than a flat surface of the film.

Furthermore, the present invention provides an adhesive film for a printed wiring board, comprising: the shape transfer film; and a circuit pattern concealing layer directly laminated with the shape transfer film.

The above-mentioned adhesive film for printed wiring board preferably has an adhesive layer, the above-mentioned circuit pattern concealing layer and the above-mentioned shape transfer film laminated in sequence.

The 85° glossiness of the surface of the shape transfer film side of the circuit pattern concealing layer is preferably below 15.

Effect of the invention According to the shape transfer film of the present invention, by making the surface have the above-mentioned specific concavo-convex shape, the shape derived from the above-mentioned concavo-convex shape can be imparted to the transfer object, thereby giving the transfer object sufficient concealment, and it can be easily peeled off from the transfer object when it is intended to be peeled off. In addition, during transportation, the shape transfer film is not easy to be peeled off except when it is intended to be peeled off from the transfer object.

Form for implementing the invention [Shape transfer film] The shape transfer film of one embodiment of the present invention has a concave-convex shape on at least one side, and is used to impart (transfer) a shape derived from the concave-convex shape to a transfer object. The shape transfer film is preferably used to impart (transfer) a shape derived from the concave-convex shape to the outermost layer (e.g., a circuit pattern concealing layer described later) of a film (printed wiring board attachment film) for attaching to a printed wiring board.

In the above-mentioned concavo-convex shape of the shape transfer film, the interface development area ratio Sdr is preferably 1500~7000%, preferably 2000~6500%, and more preferably 2500~6000%. The above-mentioned interface development area ratio Sdr is in accordance with ISO25178, and is an indicator of how much the development area (surface area) of the defined area increases relative to the area of the defined area. The Sdr of a completely flat surface will constitute 0%. If the above-mentioned interface development area ratio Sdr is above 1500%, sufficient concealment can be given to the transfer object that has been given a shape derived from the above-mentioned concavo-convex shape. If the interface development area ratio Sdr is less than 7000%, it becomes easy to peel the shape transfer film from the transfer object.

In the above-mentioned concave-convex shape, the height difference Sk of the core part is preferably 2.0~7.0μm, preferably 2.3~6.0μm, and more preferably 2.5~5.0μm. The above-mentioned core part height difference Sk follows ISO25178 and is the value of the maximum height of the core part minus the minimum height in the concave-convex shape. The core part is the area between the heights of 0% and 100% of the load area ratio of the equivalent straight line. If the above-mentioned core part height difference Sk is above 2.0μm, the height difference of the core part is large, and sufficient concealment can be given to the transfer object that has been given a shape derived from the above-mentioned concave-convex shape. If the above-mentioned core part height difference Sk is below 7.0μm, it will become easy to peel off the shape transfer film from the transfer object.

In the above-mentioned concave-convex shape, the arithmetic mean height Sa is preferably 1.0~2.0μm, preferably 1.0~1.8μm, and more preferably 1.0~1.6μm. The above-mentioned arithmetic mean height Sa is in accordance with ISO25178, which means the average of the absolute values of the height difference of each point relative to the average surface of the surface. If the above-mentioned arithmetic mean height Sa is above 1.0μm, it is possible to give more sufficient concealment to the transfer object that has been given a shape derived from the above-mentioned concave-convex shape. If the above-mentioned arithmetic mean height Sa is below 2.0μm, it will become easier to peel off the shape transfer film from the transfer object.

In the above-mentioned concave-convex shape, the root mean square height Sq is preferably 1.0~2.8μm, preferably 1.1~2.5μm, and more preferably 1.3~2.0μm. The above-mentioned root mean square height Sq is in accordance with ISO25178 and is a parameter equivalent to the standard deviation of the distance from the average plane. If the above-mentioned root mean square height Sq is above 1.0μm, it is possible to give more sufficient concealment to the transfer object that has been given a shape derived from the above-mentioned concave-convex shape. If the above-mentioned root mean square height Sq is below 2.8μm, the height unevenness in the concave-convex shape is less, and it will become easier to peel off the shape transfer film from the transfer object.

In the above-mentioned concave-convex shape, the root mean square slope Sdq is preferably 7 to 15, preferably 8 to 14, and more preferably 9 to 13.5. The above-mentioned root mean square slope Sdq is in accordance with ISO25178 and is a parameter calculated by using the root mean square of the slopes of all points in the defined area. The Sdq of a completely flat surface is 0. If the above-mentioned root mean square slope Sdq is above 7, a more sufficient concealment can be given to the transfer object that has been given a shape derived from the above-mentioned concave-convex shape. If the above-mentioned root mean square slope Sdq is below 15, the height unevenness of the concave-convex shape is less, and it will become easier to peel off the shape transfer film from the transfer object.

In the above-mentioned concavoconvex shape, the ratio of the interface development area ratio Sdr [%] to the root mean square slope Sdq [Sdr/Sdq] is preferably 200~500, preferably 250~480, and more preferably 300~450. If the above ratio is above 200, the surface area will become larger (that is, the fluctuation of the concavoconvex becomes more intense), and it is speculated that the transfer object that has been given a shape derived from the above-mentioned concavoconvex shape can be given more sufficient concealment. If the above ratio is below 500, the slope of the concavoconvex can be suppressed, and the surface area (that is, the degree of fluctuation of the concavoconvex) can also be suppressed within a certain range, thereby making it easier to peel the shape transfer film from the transfer object.

The 60° gloss of the concavo-convex shape is preferably 4.0 or more, more preferably 4.5 or more, and more preferably 5.0 or more. If the 60° gloss is 4.0 or more, it is estimated that the concavo-convex shape will constitute a shape more suitable for intentional peeling, and it will become easier to intentionally peel the shape transfer film from the transfer object. The 60° gloss can be measured by a method in accordance with JIS Z8741.

The 85° gloss of the concavo-convex shape is preferably 2.5 to 15.0, more preferably 3.0 to 13.0. If the 85° gloss is above 2.5, it will be easier to peel the shape transfer film from the transfer object. If the 85° gloss is below 15.0, the transfer object can be given more sufficient concealment. The 85° gloss can be measured by a method in accordance with JIS Z8741.

As one embodiment of the shape transfer film, there can be exemplified a shape transfer film having a base layer and a resin layer disposed on at least one side of the base layer, wherein the side surface of the resin layer has the concavo-convex shape. Also, as another embodiment of the shape transfer film, there can be exemplified a shape transfer film having the concavo-convex shape on the surface of the base layer.

In the shape transfer film, the concavo-convex shape can be formed by using a known or conventional method to have the above-mentioned various characteristics. The method of forming the concavo-convex shape can be exemplified by a method of physically roughening the flat surface by sandblasting the flat surface, spraying dry ice on the flat surface, pressing a mold having a concavo-convex shape, etc.; a method of mixing a filler so that it protrudes outward from the flat surface of the shape transfer film, etc. These methods can be used alone or in combination of two or more.

As for the embodiment of the shape transfer film having a concavo-convex shape formed by mixing fillers, the shape transfer film shown in Figures 1 and 2 can be cited. The shape transfer film 1 shown in Figure 1 has a base layer 2 and a resin layer 3 provided on one surface of the base layer 2, and the side surface of the resin layer 3 has the above-mentioned concavo-convex shape. The resin layer 3 contains fillers 4, and the fillers 4 protrude outward from the flat surface of the film, that is, the flat surface 3a of the resin layer 3, thereby forming the above-mentioned concavo-convex shape.

The substrate layer may be, for example, a plastic substrate (especially a plastic film), porous materials such as paper, cloth, nonwoven fabric, mesh, foam sheet, metal foil, etc. The substrate layer may be a single layer or a laminate of the same or different substrates. The surface of the substrate layer may be appropriately subjected to a known and conventional surface treatment such as a physical treatment such as a corona discharge treatment, a plasma treatment, or a chemical treatment such as a primer treatment.

The resin constituting the above-mentioned plastic substrate can be exemplified by low-density polyethylene, linear low-density polyethylene, medium-density polyethylene, high-density polyethylene, ultra-low-density polyethylene, random copolymer polypropylene, block copolymer polypropylene, homopolymer polypropylene, polybutene, polymethylpentene, ethylene-vinyl acetate copolymer (EVA), ionic polymer, ethylene-(meth)acrylic acid copolymer, ethylene-(meth)acrylate (random, alternating) copolymer , ethylene-butene copolymer, ethylene-hexene copolymer and other polyolefin resins; polyurethane; polyesters such as polyethylene terephthalate (PET), polyethylene naphthalate, polybutylene terephthalate (PBT); polycarbonate; polyimide; polyetheretherketone; polyetherimide; polyarylamide, wholly aromatic polyamide and other polyamides; polyphenylene sulfide; fluororesin; polyvinyl chloride; polyvinylidene chloride; cellulose resin; polysilicone resin, etc. The above resins may be used alone or in combination of two or more.

The resin forming the above-mentioned resin layer is not particularly limited, and examples thereof include thermoplastic resins, thermosetting resins, active energy ray-curing resins, and other curing resins. In addition, in this specification, the so-called "curing resin" includes both a resin that can be cured to form a resin (curable resin) and a resin formed by curing a curable resin. Among them, from the perspective of excellent peelability from the circuit pattern concealing layer described later after curing, the above-mentioned resin is preferably a curing resin. From the perspective of the hardening degree not easily changing when the printed wiring board is hot-pressed to the printed wiring board with an adhesive film, an active energy ray-curing resin is particularly preferred. The above-mentioned resins may be used alone or in combination of two or more.

Examples of the thermoplastic resin include polystyrene resins, vinyl acetate resins, polyester resins, polyolefin resins (e.g. polyethylene resins, polypropylene resin compositions, etc.), polyimide resins, acrylic resins, and the like.

Examples of the thermosetting resin include phenolic resins, epoxy resins, urethane resins, melamine resins, alkyd resins, silicone resins, and the like.

Examples of the epoxy resins include bisphenol epoxy resins, spirocyclic epoxy resins, naphthalene epoxy resins, biphenyl epoxy resins, terpene epoxy resins, glycidyl ether epoxy resins, glycidyl amine epoxy resins, and novolac epoxy resins.

Examples of the bisphenol type epoxy resin include bisphenol A type epoxy resin, bisphenol F type epoxy resin, bisphenol S type epoxy resin, tetrabromobisphenol A type epoxy resin, etc. Examples of the glycidyl ether type epoxy resin include tris(glycidoxyphenyl)methane, tetrakis(glycidoxyphenyl)ethane, etc. Examples of the glycidyl amine type epoxy resin include tetraglycidyl diamino diphenylmethane, etc. Examples of the novolac type epoxy resin include cresol novolac type epoxy resin, phenol novolac type epoxy resin, α-naphthol novolac type epoxy resin, brominated phenol novolac type epoxy resin, and the like.

The active energy ray curing resin may be, for example, a polymerizable resin having at least two free radical reactive groups (e.g., (meth)acryloyl groups) in the molecule. The active energy ray may be, for example, electron ray, ultraviolet ray, α ray, β ray, γ ray, X ray, etc.

Examples of the filler include organic particles and inorganic particles. Examples of the organic particles include acrylic resins such as polymethyl methacrylate, polyacrylonitrile resins, polyurethane resins, polyamides, polyimides, and the like. Examples of the inorganic particles include calcium carbonate, calcium silicate, clay, kaolin, talc, silica, glass, diatomaceous earth, mica powder, aluminum oxide, magnesium oxide, zinc oxide, barium sulfate, aluminum sulfate, calcium sulfate, magnesium carbonate, and the like. Only one type of the particles may be used, or two or more types may be used.

The median diameter (D50) of the filler is not particularly limited, and is preferably 0.5 to 20 μm, more preferably 1 to 10 μm. If D50 is within the above range, the above concave-convex shape can be easily formed. The above D50 refers to the particle size at 50% of the integral value in the particle size distribution obtained by the laser diffraction-scattering method.

The content of the filler in the resin layer is not particularly limited, and is preferably 20 to 70 parts by mass, more preferably 30 to 60 parts by mass, relative to 100 parts by mass of the resin forming the resin layer. If the content is within the above range, the above concavo-convex shape can be easily formed.

The thickness of the resin layer (the thickness between the two flat surfaces) is not particularly limited, and is preferably 0.5 to 9 μm, more preferably 1 to 7 μm. If the thickness is within the above range, the shape of the filler protruding from the flat surface can be set within an appropriate range by utilizing the relationship with the D50 of the filler, and the above concave-convex shape can be easily formed.

The shape transfer film 1 shown in FIG1 can be manufactured as follows: a resin layer 3 having the above-mentioned concavo-convex shape is formed on a base layer 2 by a known or conventional method. Specifically, for example, it can be manufactured as follows: a resin for forming the above-mentioned resin layer, or a composition containing a compound and a filler and optionally a solvent, is poured and coated on one side of the base layer, and then the solvent is removed or hardened to solidify.

The shape transfer film 1 shown in Fig. 2 has the above-mentioned concavo-convex shape on the surface of the base layer 2. The base layer 2 contains fillers 4, and the fillers 4 protrude outward from the flat surface of the film, that is, the flat surface 2a of the base layer 2, thereby forming the above-mentioned concavo-convex shape.

A release treatment layer may also be provided on the surface of the substrate layer having the concavo-convex shape. The release treatment layer may be, for example, a layer formed by surface treatment using a polysilicone-based, long-chain alkyl-based, fluorine-based, molybdenum sulfide-based release treatment agent. In addition, when the release treatment layer is provided, the thickness or shape of the release treatment layer may be appropriately set according to the fact that the concavo-convex shape of the substrate layer surface will not disappear, that is, the shape transfer film will have the concavo-convex shape.

The substrate layer having the above-mentioned release treatment layer may be exemplified and described as the substrate layer having the resin layer. The substrate layer without the above-mentioned release treatment layer may be a low-adhesion substrate composed of a fluoropolymer or a low-adhesion substrate composed of a non-polar polymer. The fluorine-based polymer in the above-mentioned low-adhesion substrate composed of a fluoropolymer may be polytetrafluoroethylene, polychlorotrifluoroethylene, polyvinyl fluoride, polyvinylidene fluoride, tetrafluoroethylene-hexafluoropropylene copolymer, chlorofluoroethylene-vinylidene fluoride copolymer, etc. In addition, the above-mentioned non-polar polymer may be olefin resin (e.g., polyethylene, polypropylene, etc.). The surface of the substrate layer may be appropriately subjected to a known and conventional surface treatment such as a physical treatment such as a corona discharge treatment or a plasma treatment, or a chemical treatment such as a primer treatment.

The filler mentioned above can be exemplified by those already exemplified and explained as the filler contained in the resin layer.

The median diameter (D50) of the filler is not particularly limited, and is preferably 0.5 to 20 μm, more preferably 1 to 10 μm. If D50 is within the above range, the above concave-convex shape can be easily formed. The above D50 refers to the particle size at 50% of the integral value in the particle size distribution obtained by the laser diffraction-scattering method.

The content ratio of the filler in the substrate layer is not particularly limited, and is preferably 10 to 70 volume %, more preferably 20 to 60 volume %, and more preferably 30 to 50 volume % relative to 100 volume % of the total amount of the substrate layer. If the content ratio is within the above range, the above concave-convex shape can be easily formed.

The shape transfer film 1 shown in FIG. 2 can be manufactured as follows: a substrate layer 2 is formed with the above-mentioned concavo-convex shape on at least one surface by a known or conventional method. Specifically, for example, it can be manufactured as follows: the above-mentioned filler is kneaded into a resin composition forming the substrate layer and formed. Then, a release agent can be applied and cured as needed to form a release treatment layer.

The layer (resin layer or substrate layer) having the above-mentioned concavo-convex shape may also contain other components other than the above-mentioned components within the scope of not impairing the effect of the present invention. The above-mentioned other components may include: coloring agent, antistatic agent, stabilizer, antioxidant, ultraviolet absorber, fluorescent whitening agent, etc. The above-mentioned other components may be used alone or in combination of two or more.

The thickness of the shape transfer film is not particularly limited, for example, 10 to 200 μm, preferably 15 to 150 μm. If the thickness is above 10 μm, the protection performance of the transfer object will be better. If the thickness is below 200 μm, it will be easier to peel off during use.

According to the shape transfer film, by making the surface have the above-mentioned specific concavo-convex shape, the shape derived from the above-mentioned concavo-convex shape can be given to the transfer object, thereby giving the transfer object sufficient concealment, and it can be easily peeled off from the transfer object when it is intended to be peeled off. In addition, during transportation, unless the shape transfer film is intended to be peeled off from the circuit pattern concealing layer, it is not easy to peel off in other situations.

[Adhesive film for printed wiring board] The adhesive film for printed wiring board of one embodiment of the present invention comprises: the shape transfer film and a circuit pattern concealing layer directly laminated with the shape transfer film. The surface of the circuit pattern concealing layer directly laminated on the surface having the concave-convex shape in the shape transfer film can be given (transferred) a shape derived from the concave-convex shape. Thus, when the shape transfer film is intended to be peeled off, it can be easily peeled off from the circuit pattern concealing layer, and the circuit pattern concealing layer after peeling has sufficient concealing property.

The above-mentioned adhesive film for printed wiring board preferably has an adhesive layer, the above-mentioned circuit pattern concealing layer and the above-mentioned shape transfer film laminated in this order. The above-mentioned adhesive film for printed wiring board may also have layers other than the above-mentioned adhesive layer, the above-mentioned circuit pattern concealing layer and the above-mentioned shape transfer film.

An embodiment of the above-mentioned adhesive film for a printed wiring board will be described below. Fig. 3 is a schematic cross-sectional view showing an embodiment of the above-mentioned adhesive film for a printed wiring board.

The adhesive film 5 for printed wiring board shown in FIG3 has an adhesive layer 7, a circuit pattern concealing layer 6 and the shape transfer film 1 shown in FIG1. More specifically, the adhesive film 5 for printed wiring board has the circuit pattern concealing layer 6 directly laminated on one surface of the adhesive layer 7, and the circuit pattern concealing layer 6 is a protective layer for protecting the adhesive layer 7. In addition, when the adhesive film 5 for printed wiring board adopts a conductive adhesive layer as the adhesive layer 7, the conductive adhesive layer has a function as an electromagnetic wave shielding layer and exerts electromagnetic wave shielding performance. In this case, the adhesive film 5 for printed wiring board can be used as an electromagnetic wave shielding film. Furthermore, when the adhesive layer 7 does not have shielding performance or requires higher shielding performance, another electromagnetic wave shielding layer such as a metal layer can be provided between the circuit pattern shielding layer and the adhesive layer. In this case, the circuit pattern shielding layer will be indirectly laminated on the adhesive layer.

The shape transfer film 1 is laminated on the surface of the circuit pattern concealing layer 6 opposite to the adhesive layer 7 in such a manner that the circuit pattern concealing layer 6 is in contact with the resin layer 3. The surface of the circuit pattern concealing layer 6 is directly laminated on the surface of the shape transfer film 1 having the above-mentioned concave-convex shape, and thus, a shape derived from the above-mentioned concave-convex shape can be imparted (transferred).

(Circuit pattern concealing layer) When the printed wiring board adhesive film is attached to the printed wiring board, the circuit pattern concealing layer is used as a concealing layer to make the circuit pattern in the printed wiring board difficult to be seen, and sometimes also bears design. When the adhesive layer of the printed wiring board adhesive film is attached to the printed wiring board, the side is located on the opposite side of the adhesive layer to the printed wiring board. In the printed wiring board adhesive film, the circuit pattern concealing layer can be either a single layer or a multi-layer (a laminate of multiple circuit pattern concealing layers). In addition, when another electromagnetic wave shielding layer is provided between the circuit pattern shielding layer and the adhesive layer, the circuit pattern shielding layer can protect the other electromagnetic wave shielding layer and the adhesive layer.

The circuit pattern concealing layer may also contain metal or resin as a binder component. Examples of the resin include those exemplified and described above as the resin contained in the resin layer. Examples of the metal include nickel, copper, silver, tin, gold, palladium, aluminum, chromium, titanium, zinc, and alloys containing one or more of these. The binder component may be used alone or in combination of two or more.

Among them, the above-mentioned adhesive component is preferably a resin. From the perspective of being able to change the adhesion to the above-mentioned shape transfer film before and after curing to adjust the ease of peeling, the above-mentioned resin is preferably a curing resin. From the perspective of being able to cure simultaneously when the adhesive film for the printed wiring board is hot-pressed to the printed wiring board and easily reducing the adhesion to the above-mentioned shape transfer film, a thermosetting resin is particularly preferred.

The content ratio of the adhesive component in the circuit pattern concealing layer is not particularly limited. Relative to 100% by weight of the total amount of the circuit pattern concealing layer, the content ratio is preferably 10-70% by weight, more preferably 20-60% by weight, and even more preferably 30-50% by weight.

From the perspective of achieving excellent concealment, the circuit pattern concealing layer preferably includes a black colorant. The black colorant may be a black pigment or a mixed pigment obtained by mixing a plurality of pigments to obtain a black color. Examples of the black pigment include carbon black, ketjen black, perylene black, titanium black, iron black, aniline black, etc. From the perspective of the dispersibility of the circuit pattern concealing layer, the particle size of the black pigment preferably has an average primary particle size of more than 20 nm, preferably less than 100 nm. The average primary particle size of the black pigment can be obtained from the average value of about 20 primary particles observed using an image magnified 50,000 to 1,000,000 times using a transmission electron microscope (TEM). The mixed pigment can be used after mixing red, green, blue, yellow, purple, indigo, magenta and other pigments. The content of the black colorant in the circuit pattern concealing layer is, for example, 0.5-50% by mass, preferably 1-40% by mass, relative to 100% by mass of the total amount of the circuit pattern concealing layer.

The circuit pattern concealing layer may also contain other components other than the above components within the scope of not impairing the effect of the present invention. The above other components may include: defoaming agent, viscosity regulator, antioxidant, diluent, anti-settling agent, filler, coloring agent, leveling agent, coupling agent, ultraviolet absorber, adhesive resin, hardening accelerator, plasticizer, flame retardant, anti-caking agent, hardener, etc. The above other components may be used alone or in combination of two or more.

The 60° gloss of the surface of the circuit pattern concealing layer to which the shape transfer film is attached is preferably 0.3~5.0, preferably 0.4~3.0, and more preferably 0.5~2.0. If the 60° gloss is above 0.3, it will be easier to peel off the shape transfer film. If the 60° gloss is below 5.0, the concealment will be further improved. The 60° gloss can be measured using a method in accordance with JIS Z8741. In addition, the 60° gloss is measured in a state where the shape transfer film has been peeled off from the attached film for the printed wiring board.

The 85° gloss of the surface of the circuit pattern concealing layer to which the shape transfer film is attached is preferably 15 or less, more preferably less than 15. If the 85° gloss is 15 or less, the concealment will be further improved. The 85° gloss can be measured by a method in accordance with JIS Z8741. In addition, the 85° gloss is measured in a state where the shape transfer film has been peeled off from the printed wiring board attachment film.

The circuit pattern concealing layer preferably has a total light transmittance of 20% or less, preferably 10% or less, and more preferably 5% or less. If the total light transmittance is less than 20%, it will be more difficult to discern the circuit pattern when the printed wiring board is attached to the printed wiring board with an adhesive film.

The thickness of the circuit pattern concealing layer is not particularly limited and can be appropriately set as needed. From the perspective of achieving concealment, ease of formation, and ensuring flexibility, the thickness of the circuit pattern concealing layer is preferably 1 μm or more, and more preferably 4 μm or more. In addition, the thickness of the circuit pattern concealing layer is preferably 20 μm or less, preferably 10 μm or less, and more preferably 5 μm or less.

(Adhesive layer) The adhesive layer has adhesive properties for bonding the printed wiring board adhesive film to the printed wiring board. The adhesive layer may be a single layer or a multi-layer.

The adhesive layer preferably contains a binder component constituting the resin region in the adhesive layer. The binder component may be exemplified and described above as the resin contained in the resin layer. The binder component may be used alone or in combination of two or more.

When the binder component includes a thermosetting resin, the components constituting the binder component may also include a hardener for promoting a thermosetting reaction. The hardener may be appropriately selected according to the type of the thermosetting resin. The hardener may be used alone or in combination of two or more.

The adhesive layer may be a conductive adhesive layer. If it is a conductive adhesive layer, the adhesive layer can exert electromagnetic wave shielding properties. When the adhesive layer is a conductive adhesive layer, it is more preferable to contain conductive particles.

Examples of the conductive particles include metal particles, metal-coated resin particles, metal fibers, carbon fillers, etc. Only one type of the conductive particles may be used, or two or more types may be used.

The metal particles, the metal constituting the coating of the metal-coated resin particles, and the metal constituting the metal fibers may be gold, silver, copper, nickel, zinc, etc. Only one kind of the metal may be used, or two or more kinds may be used.

Specifically, the metal particles include copper particles, silver particles, nickel particles, silver-coated copper particles, gold-coated copper particles, silver-coated nickel particles, gold-coated nickel particles, silver-coated alloy particles, etc. The silver-coated alloy particles include copper-containing alloy particles (e.g., copper alloy particles composed of an alloy of copper, nickel and zinc) and silver-coated copper alloy particles. The metal particles can be produced by electrolysis, atomization, reduction, etc.

Among them, the above metal particles are preferably silver particles, silver-coated copper particles, and silver-coated copper alloy particles. Silver-coated copper particles and silver-coated copper alloy particles are particularly preferred from the viewpoints of excellent electrical conductivity, inhibition of oxidation and aggregation of metal particles, and reduction of the cost of metal particles.

The conductive particles may be in the form of spheres, flakes (scales), branches, fibers, or amorphous shapes (polyhedrons).

The median diameter (D50) of the conductive particles is preferably 1 to 50 μm, more preferably 3 to 40 μm. If the median diameter is greater than 1 μm, the conductive particles have good dispersibility and can suppress aggregation, and are not easily oxidized. If the average particle diameter is less than 50 μm, the conductivity will be good. The D50 refers to the particle diameter at 50% of the integral value in the particle size distribution obtained by the laser diffraction-scattering method.

The conductive adhesive layer can be a layer having isotropic conductivity or anisotropic conductivity as required.

When the adhesive layer is a conductive adhesive layer, the content of the binder component in the adhesive layer is not particularly limited. Relative to the total amount of the adhesive layer (100 mass%), it is preferably 5-60 mass%, preferably 10-50 mass%, and more preferably 20-40 mass%. If the content is above 5 mass%, the electromagnetic wave shielding performance will become good. If the content is below 60 mass%, the adhesion to the printed wiring board will be more excellent.

When the adhesive layer is a conductive adhesive layer, the content of the conductive particles in the adhesive layer is not particularly limited. It is preferably 2-95% by mass, preferably 5-80% by mass, and more preferably 10-70% by mass relative to the total amount of the adhesive layer (100% by mass). If the content is above 2% by mass, the conductivity will be better. If the content is below 95% by mass, the adhesive component can be contained in sufficient amount, and the adhesion to the printed wiring board will be better.

The adhesive layer may contain other ingredients other than the above ingredients within the scope of not impairing the effect of the present invention. The above other ingredients may include ingredients contained in known or conventional adhesive layers. The above other ingredients may include defoaming agents, viscosity regulators, antioxidants, diluents, anti-settling agents, fillers, colorants, leveling agents, coupling agents, ultraviolet absorbers, adhesive resins, hardening accelerators, plasticizers, flame retardants, anti-caking agents, etc. The above other ingredients may be used alone or in combination of two or more.

The thickness of the adhesive layer is preferably 3-20 μm, more preferably 5-15 μm. If the thickness is above 3 μm, the adhesion to the printed wiring board will be better.

The above-mentioned adhesive film for printed wiring board may also have other layers other than the above-mentioned shape transfer film, the above-mentioned circuit pattern concealing layer and the above-mentioned adhesive layer. The above-mentioned other layers may be, for example, other electromagnetic wave shielding layers other than the above-mentioned conductive adhesive layer, such as a metal layer disposed between the above-mentioned circuit pattern concealing layer and the above-mentioned adhesive layer. Furthermore, when the above-mentioned other electromagnetic wave shielding layer is present, the above-mentioned other layers may be, for example, a primer layer disposed between the above-mentioned circuit pattern concealing layer and the above-mentioned other electromagnetic wave shielding layer.

The metal constituting the metal layer may be, for example, gold, silver, copper, aluminum, nickel, tin, palladium, chromium, titanium, zinc or alloys thereof. The metal layer is preferably a metal plate or a metal foil. That is, the metal layer is preferably a copper plate (copper foil) or a silver plate (silver foil).

The material forming the above-mentioned base coating layer may be exemplified by urethane resin, acrylic resin, core-shell composite resin with urethane resin as shell and acrylic resin as core, epoxy resin, polyimide resin, polyamide resin, melamine resin, phenol resin, urea-formaldehyde resin, blocked isocyanate obtained by reacting a blocking agent such as phenol with polyisocyanate, polyvinyl alcohol, polyvinyl pyrrolidone, etc. Only one of the above-mentioned materials may be used, or two or more of them may be used.

The peeling force (first peeling force) of the shape transfer film on the circuit pattern concealing layer in the above-mentioned adhesive film for printed wiring boards is preferably 0.1N or more, more preferably 0.2N or more, and more preferably 0.3N or more. If the first peeling force is 0.1N or more, it is not easy to peel off during transportation, and unintentional peeling can be suppressed. In addition, the first peeling force can be measured by the method described in the embodiment.

When the adhesive layer of the above-mentioned printed wiring board attachment film is attached to the printed wiring board and attached by heating and pressurizing, the peeling force (second peeling force) of the shape transfer film on the circuit pattern concealing layer is preferably 3.0N or less, preferably 2.0N or less, and more preferably 1.5N or less. If the second peeling force is less than 3.0N, the shape transfer film can be easily peeled off when it is intended to be peeled off during use. In addition, the second peeling force can be measured by the method described in the embodiment.

The ratio of the second peeling force to the first peeling force [second peeling force/first peeling force] is preferably 0.5 to 1.5, more preferably 0.6 to 1.3, and more preferably 0.7 to 1.2. If the above ratio is within the above range, unintentional peeling can be further suppressed, and when peeling is intended during use, peeling can be performed more easily.

The above-mentioned adhesive film for printed wiring board is particularly preferably used for flexible printed wiring board (FPC). The above-mentioned adhesive film for printed wiring board is preferably used as an adhesive film for flexible printed wiring board.

(Manufacturing method of adhesive film for printed wiring board) The manufacturing method of the adhesive film for printed wiring board described above is explained. When manufacturing the adhesive film 5 for printed wiring board shown in FIG3, first, the adhesive layer 7 and the circuit pattern concealing layer 6 are individually manufactured. Then, the adhesive layer 7 and the circuit pattern concealing layer 6 that have been manufactured individually are laminated (lamination method).

The adhesive layer 7 can be formed, for example, by coating (applying) an adhesive composition for forming the adhesive layer 7 on a temporary substrate such as a separation film or on a substrate, and removing the solvent and/or partially curing the adhesive composition as needed.

In addition to the components contained in the adhesive layer, the adhesive composition may also include a solvent. Examples of the solvent include toluene, acetone, methyl ethyl ketone, methanol, ethanol, propanol, dimethylformamide, etc. The solid component concentration of the adhesive composition may be appropriately set according to the thickness of the adhesive layer to be formed.

The adhesive composition can be applied by a known coating method. For example, a coating machine such as a gravure roll coater, a reverse roll coater, a contact roll coater, a die lip coater, a dip roll coater, a rod coater, a knife coater, a spray coater, a notched wheel coater, a direct coater, a slot die coater, etc. can be used.

On the other hand, when the circuit pattern concealing layer 6 is made of resin as a binder component, for example, the resin composition used to form the circuit pattern concealing layer 6 can be applied (coated) on the surface of the shape transfer film on which the above-mentioned concave-convex shape has been formed, and the solvent is removed and/or partially hardened and solidified as needed. In this way, the shape derived from the concave-convex surface of the shape transfer film 1 can be given to the surface of the circuit pattern concealing layer 6.

In addition to the components contained in the circuit pattern concealing layer, the resin composition may also contain a solvent. Examples of the solvent include those exemplified above as the solvent that may be contained in the adhesive composition. The solid component concentration of the resin composition may be appropriately set according to the thickness of the circuit pattern concealing layer to be formed.

The resin composition can be applied by a known coating method, for example, the coating machine described above as an example for applying the adhesive composition.

Next, the exposed surface of the adhesive layer 7 and the exposed surface of the circuit pattern concealing layer 6, which have been separately produced, are bonded together to produce the adhesive film 5 for the printed wiring board.

In other aspects other than the above-mentioned lamination method, the above-mentioned adhesive film for printed wiring board can also be manufactured by a method of sequentially laminating each layer (direct coating method). For example, the adhesive film 5 for printed wiring board shown in FIG. 3 can be manufactured as follows: a resin composition for forming a circuit pattern concealing layer 6 is coated (coated) on the surface of the adhesive layer 7, and the solvent is removed and/or partially hardened as needed, thereby solidifying it to form the circuit pattern concealing layer 6. In this case, the concavo-convex shape of the shape transfer film 1 is layered on the resin composition layer before complete curing, and then completely cured, so that the shape derived from the concavo-convex shape can be imparted to the surface of the formed circuit pattern concealing layer 6. Alternatively, it can be manufactured as follows: the circuit pattern concealing layer 6 is first formed on the concavo-convex shape surface of the shape transfer film 1, and the adhesive composition for forming the adhesive layer 7 is applied (coated) on the surface of the circuit pattern concealing layer 6, and the adhesive layer 7 is formed by removing the solvent and/or partially curing as needed.

Embodiments The present invention is described in more detail below based on embodiments, but the present invention is not limited to these embodiments.

Example 1 (Preparation of shape transfer film) A resin composition consisting of 30 parts by mass of silica particles (D50: 6.5 μm), 100 parts by mass of melamine resin and toluene was prepared, and the resin composition was applied to the surface of a 25 μm thick polyethylene terephthalate film using a wire pellet, and the solvent was removed by heating to prepare a shape transfer film having a 5 μm thick resin layer on the surface of the substrate layer.

(Preparation of adhesive film) 100 parts by mass of bisphenol A epoxy resin (trade name "jER1256", manufactured by Mitsubishi Chemical Co., Ltd.), 0.1 parts by mass of hardener (trade name "ST14", manufactured by Mitsubishi Chemical Co., Ltd.), and 15 parts by mass of carbon particles as a black colorant (trade name "TOKABLACK#8300/F", manufactured by Tokai Carbon Co., Ltd.) were mixed in toluene to prepare a resin composition having a solid content of 20% by mass. The resin composition was applied to the surface of the resin layer of the shape transfer film using a wire tablet, and cured by heating to form a circuit pattern concealing layer with a thickness of 5μm on the surface of the shape transfer film.

Next, 100 parts by mass of bisphenol A epoxy resin (trade name "jER1256", manufactured by Mitsubishi Chemical Co., Ltd.) and 0.1 parts by mass of hardener (trade name "ST14", manufactured by Mitsubishi Chemical Co., Ltd.) were mixed in toluene to a solid content of 20% by mass, and the mixture was stirred to prepare an adhesive layer composition. The adhesive layer composition was applied to a PET film (hereinafter referred to as a support film) whose surface had been subjected to a mold release treatment using a wire tablet, and cured by heating to form an adhesive layer with a thickness of 5 μm on the surface of the support film.

Next, the circuit pattern concealing layer formed on the surface of the shape transfer film and the adhesive layer formed on the surface of the support film are laminated, and a pair of metal rollers heated to 100°C are used to heat and pressurize at a pressure of 5MPa to obtain an adhesive film. The total light transmittance of the obtained adhesive film is less than 5%.

(Preparation of evaluation substrate) The above-prepared adhesive film is laminated on a printed wiring board, and then, a press is used to evacuate the board at a temperature of 170°C and a pressure of 2MPa for 60 seconds, and then heated and pressurized for 180 seconds to prepare an evaluation substrate. In addition, the above-mentioned printed wiring board is a printed wiring board on which a circuit pattern is formed on a base layer composed of a polyimide film. The above-mentioned circuit pattern is formed using a copper foil with a line width of 0.1mm and a height of 12μm. On the above-mentioned base layer, a 25μm thick adhesive layer and a covering layer (insulating film) composed of a polyimide film with a thickness of 12.5μm are provided to cover the circuit pattern.

Example 2 Except for forming a 7μm thick resin layer on the surface of the base layer, the same method as Example 1 was followed to produce a shape transfer film, an adhesive film and an evaluation substrate.

Example 3 Except that the silica particles used were silica particles with a D50 of 4.5 μm, the same method as Example 1 was followed to produce a shape transfer film, an adhesive film, and an evaluation substrate.

Example 4 Except that the silica particles used were silica particles with a D50 of 3.8 μm, the same method as Example 1 was followed to produce a shape transfer film, an adhesive film, and an evaluation substrate.

Comparative Example 1 Except that the silica particles used were silica particles with a D50 of 9 μm, the same method as Example 1 was followed to produce a shape transfer film, an adhesive film, and an evaluation substrate.

Comparative Example 2 Except that the silica particles used were silica particles with a D50 of 10 μm, the same method as Example 1 was followed to produce a shape transfer film, an adhesive film, and an evaluation substrate.

Comparative Example 3 Except that the silica particles used were silica particles with a D50 of 3.5 μm and a resin layer with a thickness of 3 μm was formed on the surface of the substrate layer, the same method as Example 1 was used to produce a shape transfer film, an attachment film and an evaluation substrate.

Comparative Example 4 Except for forming a 4μm thick resin layer on the surface of the base layer, the same procedure as in Comparative Example 3 was followed to produce a shape transfer film, an adhesive film, and an evaluation substrate.

Comparative Example 5 A film having a concave-convex shape with the properties shown in Table 1 was used as a shape transfer film. In addition, the same method as Example 1 was used to prepare an adhesive film and an evaluation substrate.

Comparative Example 6 A film having a concave-convex shape having the properties shown in Table 1, which was obtained by extruding a filler into a polyethylene terephthalate resin, was used as a shape transfer film. In addition, except for using the above-mentioned shape transfer film, the same method as Example 1 was used to produce an adhesive film and an evaluation substrate.

Comparative Example 7 A film having a concave-convex shape having the properties shown in Table 1 and formed by extruding a filler into a polyethylene terephthalate resin was used as a shape transfer film. In addition, except for using the above-mentioned shape transfer film, the same method as Example 1 was used to produce an adhesive film and an evaluation substrate.

Comparative Example 8 A film having a concave-convex shape having the properties shown in Table 1, which was obtained by sandblasting the surface of a polyethylene terephthalate film, was used as a shape transfer film. In addition, except for using the above-mentioned shape transfer film, the same method as Example 1 was used to produce an adhesive film and an evaluation substrate.

(Evaluation) Evaluation was performed as follows for each shape transfer film, adhesive film, and evaluation substrate produced in the embodiment and comparative example. The evaluation results are shown in the table.

(1) Surface shape Using a confocal microscope (trade name "OPTELICS HYBRID", manufactured by Lasertec, objective lens 100 times), in accordance with ISO25178, the interface development area ratio Sdr, core height difference Sk, arithmetic mean height Sa, root mean square height Sq and arithmetic mean of root mean square slope Sdq were measured for the concave and convex shapes formed at any five locations on the surface of the resin layer of the shape transfer film. In addition, the cutoff wavelength of the S filter was set to 0.0025 mm, and the cutoff wavelength of the L filter was set to 0.8 mm.

(2) Gloss The 60° gloss and 85° gloss of the concavo-convex shapes formed on the resin layer surface of the shape transfer film and the 60° gloss and 85° gloss of the area on the surface of the circuit pattern concealing layer of the evaluation substrate to which the concavo-convex shapes were transferred were measured using a Gardner micro gloss (portable gloss meter, manufactured by BYK). The gloss of the circuit pattern concealing layer surface was measured after the shape transfer film was peeled off from the evaluation substrate.

(3) Peeling force before heating and pressing (first peeling force) The peeling force when the shape transfer film is peeled off from the adhesive film (before heating and pressing) prepared in the above-mentioned embodiment and comparative example is measured as the first peeling force. Specifically, the adhesive film is fixed on a polyimide film with a thickness of 100 μm, and a strength tester (trade name "PFT50S", PALMEC Co., Ltd.) is used to evaluate the peeling force (first peeling force) when the shape transfer film is peeled off from the adhesive film under the conditions of a sample width of 10 mm, a peeling angle of 170°, and a peeling speed of 1000 mm/min.

(4) Peeling force after heating and pressing (second peeling force) The peeling force when the shape transfer film is peeled off from the evaluation substrate after heating and pressing when the evaluation substrate is prepared is measured as the second peeling force. Specifically, the peeling force (second peeling force) when the shape transfer film is peeled off from the evaluation substrate is evaluated using a strength tester (trade name "PFT50S", PALMEC Co., Ltd.) under the conditions of a sample width of 10 mm, a peeling angle of 170°, and a peeling speed of 1000 mm/min.

(5) Concealment Place the evaluation substrate on a flat table, peel off the shape transfer film, and evaluate whether the circuit pattern can be seen from the circuit pattern concealment layer side at a height of 30 cm and an angle of 45° under an environment with a surface illumination of 500 lux on the shielded wiring board. If the circuit pattern cannot be seen, it is evaluated as good concealment (○), and if the circuit pattern can be seen, it is evaluated as poor concealment (×).

[Table 1]

In the shape transfer film of the embodiment, the concealing property of the circuit pattern concealing layer formed by using the shape transfer film is excellent, and the peeling force (the second peeling force) after heating and pressing is as low as below 2.0N, and the peeling property from the circuit pattern concealing layer is also excellent. In addition, the peeling force (the first peeling force) before heating and pressing is above 0.1N, and the shape transfer film shows that it is not easy to peel off under unintentional conditions. On the other hand, when the interface development area ratio Sdr or the core height difference Sk on the surface of the shape transfer film is larger (comparison examples 1 and 2), the second peeling force will be greater than 2.0N, and the peeling property from the circuit pattern concealing layer is poor. Furthermore, when the interface development area of the shape transfer film surface is smaller than Sdr or the core height difference Sk (Comparative Examples 3 to 8), the concealment of the circuit pattern concealing layer is poor. Furthermore, in Comparative Example 8, the second peeling force is greater than 2.0N, and the peeling property from the circuit pattern concealing layer is also poor.

1: Shape transfer film 2: Base material layer 2a, 3a: Flat surface of shape transfer film 3: Resin layer 4: Filler 5: Adhesive film for printed wiring board 6: Circuit pattern concealing layer 7: Adhesive layer

FIG. 1 is a schematic cross-sectional view showing one embodiment of the shape transfer film of the present invention. FIG. 2 is a schematic cross-sectional view showing another embodiment of the shape transfer film of the present invention. FIG. 3 is a schematic cross-sectional view showing one embodiment of an adhesive film for a printed wiring board using the shape transfer film shown in FIG. 1.

1: Shape transfer film

2: Base material layer

3: Resin layer

3a: Flat surface of shape transfer film

4: Filling

Claims (12)

A shape transfer film has a concave-convex shape with an interface development area ratio Sdr of 1500-7000% on at least one side, and is used to transfer a shape derived from the concave-convex shape to a transfer object; the shape transfer film satisfies the following (i) and/or (ii): (i) having a substrate layer and a resin layer disposed on at least one side of the substrate layer, and the resin forming the resin layer is a curable resin; (ii) having a substrate layer, and the surface of the substrate layer has the concave-convex shape. As in claim 1, the shape transfer film, wherein the core height difference Sk of the aforementioned concave-convex shape is 2.0~7.0μm. A shape transfer film, at least one side of which has a concavo-convex shape with a core height difference Sk of 2.0-7.0 μm, for transferring a shape derived from the concavo-convex shape to a transfer object; the shape transfer film satisfies the following (i) and/or (ii): (i) having a substrate layer and a resin layer disposed on at least one side of the substrate layer, the resin forming the resin layer is a curable resin; (ii) having a substrate layer, the surface of the substrate layer having the concavo-convex shape. A shape transfer film as claimed in any one of claims 1 to 3, wherein the arithmetic mean height Sa of the concave-convex shape is 1.0 to 2.0 μm. A shape transfer film as claimed in any one of claims 1 to 3, wherein the root mean square height Sq of the aforementioned concave-convex shape is 1.0~2.8μm. A shape transfer film as claimed in any one of claims 1 to 3, wherein the root mean square slope Sdq of the concave-convex shape is 7 to 15. A shape transfer film as claimed in any one of claims 1 to 3, wherein the ratio of the interface development area ratio Sdr of the aforementioned concave-convex shape to the root mean square slope Sdq [Sdr/Sdq] is 200-500. The shape transfer film as claimed in any one of claims 1 to 3 comprises a substrate layer and a resin layer disposed on one side of the substrate layer, and the side surface of the resin layer has the concave-convex shape. A shape transfer film as claimed in any one of claims 1 to 3, wherein the shape transfer film contains fillers, and the concave-convex shape is formed by making the fillers protrude outwards more than the flat surface of the film. A bonding film for a printed wiring board, comprising: a shape transfer film as in any one of claims 1 to 9; and a circuit pattern concealing layer, which is directly laminated with the shape transfer film. For example, the adhesive film for printed wiring boards of claim 10 is sequentially laminated with an adhesive layer, the aforementioned circuit pattern concealing layer, and the aforementioned shape transfer film. As in claim 11, the adhesive film for printed wiring boards, wherein the 85° glossiness of the surface of the shape transfer film side of the aforementioned circuit pattern concealing layer is less than 15.