JP7218771B2 - Concave-convex transfer film - Google Patents

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an unevenness transfer film, and more particularly to an unevenness transfer film for transferring unevenness to the surface of a film product used in electronic equipment to impart a matte appearance quality.

2. Description of the Related Art Circuit boards in electronic devices such as mobile phones and personal computers are widely provided with electromagnetic shielding measures to prevent malfunction due to electromagnetic noise from the outside and electromagnetic noise emitted from electronic components inside the devices.

An electromagnetic wave shielding film is generally used as an electromagnetic wave shielding measure, and such an electromagnetic wave shielding film has a protective layer and a shield layer. One method for producing an electromagnetic wave shielding film having the above structure is to use a transfer film. A protective layer is coated on the transfer film, and a shield layer and an adhesive layer are further laminated on the protective layer, An adhesive layer, a shield layer, and a protective layer are transferred onto the transferred material by a hot press. As the transfer film used in the manufacturing method, a concavo-convex transfer film having a matte transfer surface is used for the purpose of designing the protective layer to be transferred.

As the uneven layer of the uneven transfer film, a sandblasting treatment, a matte coating treatment, a hairline treatment, a chemical etching treatment, or a film subjected to a kneading matte treatment by adding particles to the inside of the film has been proposed. (For example, Patent Document 1, Patent Document 2)

In recent years, in order to further improve the designability of the protective layer, a higher matt feeling is required on the surface of the protective layer. However, with the sandblasting disclosed in Patent Documents 1 and 2, it is difficult to further roughen the film surface, and when a sandblasted film is used as the transfer film, it is difficult to improve the mattness of the protective layer. rice field. In addition, no other methods for improving the matte property are disclosed.

On the other hand, as a method for making unevenness on the surface of the transfer film, a kneaded mat that adds particles to the inside of the base film (Patent Document 3, Patent Document 4) and a coating mat that coats the base film containing particles (Patent Document 3) Reference 5) has been proposed.

In Patent Documents 3 and 4, a matte property is exhibited by providing a matte layer containing synthetic zeolite particles in a polyester film. However, even the lowest glossiness among the exemplified ones is about 11%, which is not sufficient.

In Patent Document 5, a mat layer is provided by coating the surface of a polyester film with an aqueous dispersion of an acid-modified polyolefin resin containing a matting agent. The glossiness is 16%, which cannot be said to have sufficient mattness.

Until now, it is known that a high matte tone can be expressed by lowering the glossiness, but it is difficult to reduce the glossiness to 10% or less without causing the particles to fall off, etc. Therefore, the designability of the protective layer could not be increased.

Japanese Patent Application Laid-Open No. 2004-231727 (Example 2) JP 2016-40852 A JP 2013-129076 A JP 2015-185659 A JP 2012-40707 A

In view of the above circumstances, the present invention provides a concavo-convex transfer film that has a concavo-convex layer that is a coating layer, prevents particles from falling off, reduces the gloss of the surface of the concavo-convex layer, and improves the matte properties of the surface to be transferred. The challenge is to provide.

That is, the present invention consists of the following configurations.
1. The film has an uneven layer on at least one side, the uneven layer is a coating layer containing a resin and particles, and the total value of the polar component (γsd) and the hydrogen bond component (γsh) of the surface free energy on the surface of the uneven layer is 5 mJ/m ² or less, and the 60° gloss of the uneven layer surface is 5
% or less.
2. 3. The concavo-convex transfer film as described in 1 above, wherein the surface of the concavo-convex layer does not substantially contain an Si component.
3. One side of the film has an uneven surface, the 60° gloss of the surface having the uneven surface is 5% or less, and the increase rate of the 60° gloss after applying a pressure press of 40 MPa for 30 seconds is
The concave-convex transfer film according to the first or second aspect, wherein the gloss is 25% or less with respect to the 60° gloss before applying the pressurization.
4. The concavo-convex transfer film as described in any one of the above 1 to 3, wherein the concavo-convex layer surface has a surface roughness Ra of 0.2 μm or more and 2.5 μm or less.
5. Any one of the above 1st to 4th, wherein the total amount of particles contained in the uneven layer is 40% by mass or more and 200% by mass or less with respect to the entire resin composition that is a binder component of the uneven layer. 3. The concavo-convex transfer film according to .
6. The above first to fifth, wherein the average particle diameter of the particles is 1 μm or more and 10 μm or less
3. The concavo-convex transfer film according to any one of .
7. 6. The concavo-convex transfer film as described in any one of the above 1 to 6, which is used for forming a protective layer of an electronic device part.

By using the concavo-convex transfer film of the present invention, it is possible to provide a film for electronic devices, such as an electromagnetic wave shielding film, which has excellent matte properties on the surface to be transferred.

It is a cross-sectional schematic diagram of the concavo-convex transfer film of the present invention. It is a cross-sectional schematic diagram which shows the laminated state in the case of transferring using the concavo-convex transfer film of the present invention.

(Concave-convex transfer film)
The unevenness transfer film of the present invention is a film having surface unevenness on at least one side, and preferably comprises a substrate film 11 and an uneven layer 12, as shown in FIG. 1, for example. Although it is preferable for the uneven layer 12 to exhibit releasability, it is also possible to further provide a release layer 13 on the uneven layer 12 in order to further improve the releasability. The uneven layer 12 preferably contains at least a binder resin and particles 14 . By including the particles 14 in the uneven layer 12, it is possible to provide an uneven transfer film having appropriate surface unevenness.

Then, for example, as shown in FIG. 2, the uneven transfer film of the present invention is obtained by laminating a protective layer 23 and a shield layer 22 in this order on the uneven layer 12 in order to manufacture an electromagnetic wave shielding film. , a protective layer 2 on a transferred object 21 such as a CCL for flexible substrates.
3 and the shield layer 22 are preferably transferred. An adhesive layer may be further provided between the shield layer 22 and the transferred material 21 in some cases. Since the surface of the uneven layer 12 of the uneven transfer film has fine unevenness, the fine unevenness is transferred to the surface of the protective layer 23 in contact with the uneven layer 12, resulting in a matte appearance quality. It will be. As a result, the protective layer side surface of the electromagnetic wave shielding film to which the shield layer 22 and the protective layer 23 are transferred has fine irregularities and a matte appearance quality. As described above, a release layer 13 may be provided between the uneven layer 12 and the protective layer 23 in order to further improve release properties.

Hereinafter, in the unevenness transfer film of the present invention, a layer structure having an uneven layer on a base film will be described as an example.

(Base film)
Resins constituting the film used as the base material in the present invention include polyolefin resins such as polyethylene and polypropylene, polyamide resins such as nylon 6 and nylon 66, polyethylene terephthalate, polybutylene terephthalate, polyethylene-2,6-naphthalate, and polytrimethylene. Examples of terephthalate and copolymerization components include diol components such as diethylene glycol, neopentyl glycol, and polyalkylene glycol, and dicarboxylic acid components such as adipic acid, sebacic acid, phthalic acid, isophthalic acid, and 2,6-naphthalenedicarboxylic acid. can be used. Among them, polyester resin is preferable from the viewpoint of mechanical strength, chemical resistance and heat resistance.

Polyester resins particularly preferably used as the base film in the present invention are polyethylene terephthalate, polytrimethylene terephthalate, polybutylene terephthalate, and polyethylene naphthalate, and these may be used in combination. Among these polyester resins, polyethylene terephthalate is most preferable from the viewpoint of balance between physical properties and cost. Further, these polyester films can be biaxially stretched to improve their chemical resistance, heat resistance, mechanical strength, and the like.

Moreover, the polyester film may be a single layer or a multilayer. In addition, each of these layers may contain various additives in the polyester resin, if necessary, as long as the effect of the present invention is achieved. Examples of additives include antioxidants, light stabilizers, gelling agents, organic wetting agents, ultraviolet absorbers, and surfactants.

The base film used in the present invention may be transparent or colored. The coloring method is not particularly limited, but coloring can be performed using pigments or dyes. For example, it is preferable to form a white film by mixing a white pigment such as titanium oxide, because the visibility can be improved.

The thickness of the base film used in the present invention is not particularly limited, but can be arbitrarily determined within the range of 12 to 500 μm according to the standards used. The upper limit of the thickness of the base film is preferably 350 μm, and a thickness of 350 μm or less is preferable because there is no decrease in productivity and handling properties. On the other hand, the lower limit of the film thickness is preferably 25 μm, and if it is 25 μm or more, the mechanical strength of the base film will not be insufficient, and the transfer film will not break when peeled off.

The base film used in the present invention can also be provided with an anchor layer. By providing the anchor layer, the adhesiveness to the substrate film is improved when the irregular layer is formed, which will be described later. The anchor layer may be coated in-line during the formation of the base film, or may be coated off-line after the formation of the base film. In-line processing is preferable from the viewpoint of cost.

The resin used for the anchor layer is not particularly limited, and known resins can be used. For example, polyester-based resins, acrylic-based resins, polyurethane-based resins, polyvinyl alcohol-based resins, and polycarbonate-based resins can be used.

For the anchor layer, it is also possible to use a cross-linking agent in combination with the above resin. Although the cross-linking agent is not particularly limited, isocyanate-based, melamine-based, carbodiimide-based, oxazoline-based, epoxy-based, and the like can be used. One type or two or more types can be used without limitation.

In the anchor layer, additives other than the resin and cross-linking agent described above may be used as necessary. Examples of additives that can be used include particles, catalysts, surfactants, UV absorbers, initiators, antistatic agents, and the like.

(Uneven layer)
The uneven layer of the uneven transfer film of the present invention is preferably a coating layer containing at least a resin and particles on a substrate film. By adding a resin and particles, and selecting the resin and particles so as to satisfy the range of surface free energy and 60° gloss described later, it is possible to provide a concavo-convex transfer film with high mattness and good transferability.

The uneven layer in the present invention preferably has a total value of the polar component (γsp) and the hydrogen bond component (γsh) of the surface free energy of 5 mJ/m ² or less. More preferably, the total value of the surface free energy polar component (γsp) and hydrogen bond component (γsh) is 3 mJ/m ² or less. More preferably, it is 1 mJ/m ² or less. When the sum of the polar component (γsp) and the hydrogen bond component (γsh) of the surface free energy is 5 mJ/m ² or less, it is preferable because the releasability at the time of peeling after the heating process is not impaired. If the total value of the polar component and the hydrogen bond component of the surface free energy of the uneven layer is 5 mJ/m ² or less, any known binder resin, particles, or additives can be mixed and used as the binder component of the uneven layer. good too.

In the unevenness transfer film of the present invention, the 60° gloss of the surface having surface unevenness is preferably 5% or less, more preferably 4% or less, and more preferably 2% or less. If it is 5% or less, it is preferable because the intended design property can be easily imparted to the transferred surface of the protective layer. If it exceeds 5%, the intended design of the transfer surface of the protective layer becomes insufficient, which is not preferable.

Preferably, the uneven layer of the present invention does not substantially contain a compound containing Si element. Materials containing Si element include silica particles such as silicone resins and silicon dioxide, and organic compounds and inorganic compounds such as silane coupling agents. When a film containing Si is used as a transfer film for an electronic component or the like, it may migrate to the electronic component and cause problems, so it is preferable not to include it. “Substantially free” means not only not intentionally added but also almost no peak derived from Si is detected when the uneven layer surface is analyzed by ESCA (X-ray photoelectron spectroscopy) or the like. Substantially not detected means 0.1% or less relative to other detected elements. If the concave-convex layer is an organic compound, Si element should be 0.1% or less with respect to C element.

Each component and the like for forming the concavo-convex layer will be described below.

(resin)
The resin used for the uneven layer of the present invention is not particularly limited, but mainly acrylic resins, polyester resins, urethane resins, melamine resins, epoxy resins, silicone resins, olefin resins, fluorine It can be composed of a system resin or the like. One type may be used, or two or more types of resin may be mixed. However, when used for molding electronic devices, it is preferable not to use a resin containing an Si component such as silicone.

Examples of the olefin-based resin used for the uneven layer include copolymerized polyethylene, cyclic polyolefin, and polymethylpentene. From the viewpoint of heat resistance, it is preferable to use cyclic polyolefin, polymethylpentene, and the like. It is preferable to use the above-described resin for the uneven layer because the mold releasability can be maintained even after high-temperature treatment.

Copolymerized polyethylene can be obtained by copolymerizing polyethylene with α-olefins such as propylene, n-butene, n-pentene and n-hexene. Adhesion to the polyester film can be improved by introducing a functional group such as a hydroxyl group or a carboxyl group into these resins and cross-linking them with a cross-linking agent.

A cyclic polyolefin is a resin containing a cyclic olefin as a polymer component. Cyclic olefins are polymerizable cyclic olefins having an ethylenic double bond in the ring, and can be classified into monocyclic olefins, bicyclic olefins, tricyclic or higher polycyclic olefins, and the like. Examples of monocyclic olefins include cyclic C4-12 cycloolefins such as cyclobutene, cyclopentene, cycloheptene, cyclooctene, and the like. Examples of bicyclic olefins include 2-norbornene; alkyl groups such as 5-methyl-2-norbornene, 5,5-dimethyl-2-norbornene, 5-ethyl-2-norbornene, 5-butyl-2-norbornene (C1-4 alkyl group) norbornenes; norbornenes having alkenyl groups such as 5-ethylidene-2-norbornene; 5-methoxycarbonyl-2-norbornene, 5-methyl-5-methoxycarbonyl-2-norbornene and the like norbornenes having an alkoxycarbonyl group; norbornenes having a cyano group such as 5-cyano-2-norbornene; 5-phenyl-2-norbornene, 5-phenyl-5-methyl-2-norbornene having an aryl group norbornenes; octaline; octaline having an alkyl group such as 6-ethyl-octahydronaphthalene;

Examples of polycyclic olefins include dicyclopentadiene; 2,3-dihydrodicyclopentadiene, methanooctahydrofluorene, dimethanooctahydronaphthalene, dimethanocyclopentadienonaphthalene, methanooctahydrocyclopentadienonaphthalene, etc. derivatives having substituents such as 6-ethyl-octahydronaphthalene; adducts of cyclopentadiene and tetrahydroindene and the like; trimers and tetramers of cyclopentadiene;

These cyclic olefins can be used alone or in combination of two or more. Among these cyclic olefins, it is preferable to use a bicyclic olefin because both flexibility and releasability can be achieved. The ratio of bicyclic olefins (especially norbornenes) to the total cyclic olefins may be 10 mol% or more, for example, 30 mol% or more, preferably 50 mol% or more, more preferably 80 mol% or more. , bicyclic olefin alone (100 mol %). In particular, when the proportion of tricyclic or higher polycyclic olefins becomes large, it is not preferable because it becomes difficult to use for roll-to-roll production.

Specific examples of bicyclic olefins include norbornene (2-norbornene, optionally having substituents), octaline (octahydronaphthalene, optionally having substituents), and the like. Examples of the substituents include alkyl groups, alkenyl groups, aryl groups, hydroxyl groups, alkoxy groups, carboxyl groups, alkoxycarbonyl groups, acyl groups, cyano groups, amide groups, and halogen atoms. These substituents may be used alone or in combination of two or more. Among these bicyclic olefins, norbornenes such as norbornene and norbornene having an alkyl group (C1-4 alkyl group such as methyl group and ethyl group) are particularly preferred.

The cyclic polyolefin is preferably a cyclic olefin-chain olefin copolymer further containing a chain olefin as a polymerization component. By using the above copolymer, flexibility can be imparted and processing becomes easier.

Examples of chain olefins include chain C2 such as ethylene, propylene, 1-butene, isobutene, 1-pentene, 3-methyl-1-pentene, 4-methyl-1-pentene, 1-hexene, and 1-octene. -10 olefins and the like. These chain olefins can be used alone or in combination of two or more. Among these chain olefins, α-chain C2-8 olefins are preferred, and α-chain C2-4 olefins (especially ethylene) are more preferred.

The ratio (molar ratio) between the cyclic olefin and the chain olefin is, for example, cyclic olefin/chain olefin = 100/0 to 1/99, preferably 90/10 to 10/90, more preferably 70/30 to 20. /80. If the proportion of the cyclic olefin is too small, the heat resistance is lowered and the releasability is also lowered, which is not preferable.

Other copolymerizable monomers include, for example, vinyl ester-based monomers (e.g., vinyl acetate, vinyl propionate, etc.); diene-based monomers (e.g., butadiene, isoprene, etc.); Monomers [eg, (meth)acrylic acid, derivatives thereof ((meth)acrylic acid esters, etc.)] and the like can be exemplified. These other copolymerizable monomers may be used alone or in combination of two or more. The content of these other copolymerizable monomers is, for example, 5 mol % or less, preferably 1 mol % or less, relative to the entire cyclic polyolefin.

The cyclic polyolefin may be a resin obtained by addition polymerization, or may be a resin obtained by ring-opening polymerization (such as ring-opening metathesis polymerization). Also, the polymer obtained by ring-opening metathesis polymerization may be a hydrogenated resin. The cyclic polyolefin can be polymerized by conventional methods such as ring-opening metathesis polymerization using a metathesis polymerization catalyst, addition polymerization using a Ziegler-type catalyst, addition polymerization using a metallocene catalyst (generally, metathesis polymerization catalyst ring-opening metathesis polymerization) and the like can be used.

The glass transition temperature (Tg) of the cyclic polyolefin used in the present invention can be selected from the range of about 10 to 250°C. ~250°C. If the glass transition temperature is too low, the heat resistance is lowered, and if it is too high, roll-to-roll production becomes difficult.

The number average molecular weight of the cyclic polyolefin is, for example, about 1000 to 150,000, preferably 5,000 to 120,000, more preferably about 10,000 to 100,000 (especially about 20,000 to 90,000) in terms of polystyrene in gel permeation chromatography (GPC).

Commercially available cyclic polyolefins include ARTON (registered trademark) (manufactured by JSR), ZEONOR (registered trademark) (manufactured by Nippon Zeon), APEL (manufactured by Mitsui Chemicals), TOPAS (registered trademark) (manufactured by Polyplastics). ) and can be preferably used.

The polymethylpentene resin used for the concavo-convex layer in the present invention is a copolymer containing at least the structural unit A and the structural unit B. Structural unit A preferably contains a total of 50 mol% or more, more preferably 70 mol% or more, and 85 mol% or more of a resin derived from 4-methyl-1-pentene and/or 3-methyl-1-pentene. It is more preferable to include Each may be used alone or in combination.

Structural unit B is preferably composed of at least one olefin-derived resin selected from ethylene and α-olefins having 3 to 4 carbon atoms and is contained in an amount of 5 mol % or more. The upper limit of the content of the structural unit B is preferably 50 mol% or less, more preferably 30 mol% or less, and even more preferably 15 mol% or less.

Preferred examples of the α-olefin having 3 to 4 carbon atoms used in the structural unit B include 1-butene and propylene, but propylene is more desirable from the viewpoint of physical properties. α-olefins having 3 to 4 carbon atoms, ethylene, and the like may be used alone or in combination.

In addition to the structural unit A and the structural unit B, the polymethylpentene resin may have other polymerizable compounds as structural units. For example, vinyl compounds having a cyclic structure such as styrene, vinylcyclopentene, vinylcyclohexane, and vinylnorbornane; vinyl esters such as vinyl acetate; unsaturated organic acids such as methacrylic acid, acrylic acid and maleic anhydride, or derivatives thereof; butadiene, conjugated dienes such as isoprene and pentadiene; and non-conjugated polyenes such as 1,4-hexadiene, octadiene, cyclopentadiene, norbornene and norbornadiene.

The above-mentioned other polymerizable compound can be contained in a ratio of 10 mol % or less with respect to the total 100 mol % of the structural unit A and the structural unit B. More preferably, it is 5 mol % or less.

The polymethylpentene resin used in the present invention may be modified, and preferably has one or more functional groups such as an acid anhydride group, a hydroxyl group, an active hydrogen-containing group such as a carboxyl group, and an epoxy group. one of. By having these functional groups, it is possible to improve the adhesion to polyester resins such as polyethylene terephthalate and polyethylene naphthalate when used in combination with a cross-linking agent. These functional groups can be introduced by known methods. The amount of functional groups to be introduced is preferably 10 equivalents or less with respect to the polymethylpentene resin.

The polymethylpentene resin used in the present invention can be polymerized by a known method, and can be obtained by polymerization under a catalyst for olefin polymerization such as a metallocene catalyst.

The polyester-based resin used for the uneven layer of the present invention is not particularly limited, and known ones can be used. For example, copolyester resins, alkyd resins, and the like can be suitably used.

Fluorine-based resins preferably used in the present invention include PTFE (polytetrafluoroethylene), PVDF (polyvinylidene fluoride), PCTFE (polychlorotrifluoroethylene), PVF (polyvinyl fluoride), and the like. Copolymers, PFA (copolymer of tetrafluoroethylene (C ₂ F ₄ ) and perfluoroalkoxyethylene), FEP (copolymer of tetrafluoroethylene and hexafluoropropylene), ETFE (tetrafluoroethylene (- C ₂ F ₄ -) and ethylene (-C ₂ H ₄ -)). Also, an acrylate-modified fluorine-based resin can be added to a polyfunctional acrylate or the like and used.

The acrylic resin used for the uneven layer of the present invention is not particularly limited, and known resins can be used. For example, an actinic radiation-curable acrylic resin can be used, and the actinic radiation-curable acrylic resin may contain a polyfunctional acrylate, an acrylic oligomer, or a reactive diluent as a polymerizable component.

Acrylic oligomers include polyester acrylates, urethane acrylates, epoxy acrylates, polyether acrylates, etc., including those in which reactive acrylic groups are bonded to the acrylic resin skeleton. A compound in which an acrylic group is bound to a similar skeleton can also be used.

In addition, the reactive diluent serves as a medium for the coating agent and serves as a solvent in the coating process. It becomes a polymerization component.

The above resin may optionally contain a photoinitiator, a photosensitizer, a thermal polymerization initiator, a modifier, or the like.

Specific examples of photoinitiators include acetophenone, 2,2-diethoxyacetophenone, p-dimethylacetophenone, p-dimethylaminopropiophenone, benzophenone, 2-chlorobenzophenone, 4,4'-dichlorobenzophenone, 4,4'-bisdiethylaminobenzophenone, Michler's ketone, benzyl, benzoin, benzoin methyl ether, benzoin ethyl ether, benzoin isopropyl ether, methyl benzoyl formate, p-isopropyl-α-hydroxyisobutylphenone, α-hydroxyisobutylphenone, 2, Using carbonyl compounds such as 2-dimethoxy-2-phenylacetophenone and 1-hydroxycyclohexylphenyl ketone, sulfur compounds such as tetramethylthiuram monosulfide, tetramethylthiuram disulfide, thioxanthone, 2-chlorothioxanthone, and 2-methylthioxanthone can be done. These photopolymerization initiators may be used alone or in combination of two or more.

The appropriate amount of the photopolymerization initiator to be used is 0.01 to 10 parts by mass with respect to 100 parts by mass of the resin composition. When electron beams or gamma rays are used as curing means, it is not always necessary to add a polymerization initiator.

Examples of other resins that can be used include alkyd resins and acrylic resins modified with stearyl or lauryl, or alkyd resins and acrylic resins obtained by reaction of methylated melamine.

Examples of aminoalkyd resins obtained by reaction of methylated melamine include Tesfine 303, Tesfine 305 and Tesfine 314 manufactured by Hitachi Chemical Co., Ltd. Examples of aminoacrylic resins obtained by reaction of methylated melamine include Tesfine 322 manufactured by Hitachi Chemical Co., Ltd.

When the thermosetting resin described above is used as the resin (A), one kind may be used, or two or more kinds of resins may be mixed. In order to further improve hardness and durability against pressure, it is also preferable to use a cross-linking agent.

Examples of cross-linking agents used above include isocyanates, carbodiimides, oxazolines, silane coupling agents, and melamine.

(particle)
The average particle diameter of the particles contained in the uneven layer of the present invention is preferably 0.3 μm or more and 10 μm or less. When the average particle diameter is 0.3 μm or more, the uneven surface effect of the uneven layer can be obtained, which is preferable. More preferably, it is 2 μm or more. When the particle size is 10 μm or less, it is preferable because there is no possibility that the particles will fall off. More preferably, it is 8 μm or less.

The average particle diameter of the particles was measured by observing the cross section of the film after processing with a scanning electron microscope, observing 100 particles, and taking the average value as the average particle diameter.

The shape of the particles is not particularly limited as long as it satisfies the object of the present invention, and spherical particles and irregularly shaped non-spherical particles can be used. The particle diameter of amorphous particles can be calculated as a circle equivalent diameter. The circle-equivalent diameter is a value obtained by dividing the observed particle area by π, calculating the square root, and doubling the result.

Specific examples of the particles include, for example, organic particles such as crosslinked polymethyl methacrylate particles, crosslinked methyl methacrylate-styrene copolymer particles, crosslinked polystyrene particles, crosslinked methyl methacrylate-methyl acrylate copolymer particles, and crosslinked alkyl acrylate-styrene particles. Examples thereof include resin particles such as copolymer particles, crosslinked alkyl methacrylate-styrene copolymer particles, melamine/formaldehyde resin particles, benzoguanamine/formaldehyde resin particles, and polyacrylonitrile particles. In particular, cross-linked ones are preferable in terms of heat resistance and durability against pressure. Inorganic particles can also be used, such as silica particles, alumina particles, calcium carbonate particles, titanium oxide particles, and the like. In electronic parts, it is preferable to use organic particles because there is concern about deterioration in performance due to inorganic substances and Si components.

The particles contained in the uneven layer may be of one type or may be a mixture of two or more types. In order to effectively reduce the gloss of the uneven layer surface, it is preferable to use two or more kinds of particles having different particle diameters. At this time, the particles may be organic particles or inorganic particles. They may be of the same type or of different types. For example, PMMA organic particles (e.g., Eposter (registered trademark) manufactured by Nippon Shokubai Co., Ltd.) and modified organic polymer particles (e.g., CERAFLOUR (registered trademark) 1000, manufactured by BYK-Chemie Japan) may be used in combination. be. (CERAFLOUR (registered trademark) 1000, manufactured by BYK-Chemie Japan), the manufacturer does not seem to announce the exact chemical composition, so the description is limited to modified organic polymer particles announced by the manufacturer. )

The content of the particles is preferably 20% by mass, more preferably 40% by mass or more, and still more preferably more than 70% by mass with respect to the entire resin composition that serves as the binder component of the uneven layer. is. If it is 20% by mass or more, it is preferable because a sufficient matte property can be formed on the surface of the uneven layer. On the other hand, the content of particles contained in the uneven layer is preferably 200% by mass or less. More preferably, it is 160% by mass or less. When the content is 200% by mass or less, the particles are not detached and the mechanical strength of the uneven layer is not lowered, which is preferable. Moreover, when multiple types of particles are contained, the total amount of the multiple types of particles is defined as the content of the particles. In the present application, "the entire resin composition that serves as a binder component of the uneven layer" does not contain the organic particles when the particles contained in the uneven layer are organic particles (of course, it does not include inorganic particles. ) is the purpose. Therefore, for example, when there is another binder resin other than the resin component that mainly serves as the binder component of the uneven layer, such as the above resin, the resin component of the uneven layer containing the other binder resin is added to the entire resin composition. and

(Additive)
Various additives may be added to the concavo-convex layer of the concavo-convex transfer film of the present invention in order to impart other functionality to the extent that the concavity and convexity of the concavo-convex layer is not impaired. Examples of the additives include fluorescent dyes, fluorescent whitening agents, plasticizers, ultraviolet absorbers, pigment dispersants, foam inhibitors, antifoaming agents, leveling agents, preservatives, antistatic agents, and the like. It is preferable not to use additives containing a Si component, since there is a concern that the performance of the electronic components may deteriorate.

(Visibility improvement additive)
It is also preferable to add a dye and/or a pigment to the uneven layer of the uneven transfer film of the present invention in order to improve visibility. Furthermore, it is also one of preferred forms to provide an anchor layer between the substrate film and the uneven layer and to add a dye and/or a pigment to the anchor layer. It is also preferable to provide a coating layer on the surface of the substrate film opposite to the surface on which the uneven layer is provided, and to color the coating layer.

The film thickness of the uneven layer preferably satisfies the following formula (1).
(1/4)×D≦d≦(3/2)×D (1)
Here, d is the film thickness of the uneven layer, and D is the average particle diameter of the particles (B).
If d is larger than 3/2 of D, the particles tend to be buried in the coating film, making it difficult to obtain a sufficient surface unevenness effect, which is not very preferable. If d is smaller than 1/4 of D, durability against pressure may be lowered, which is not very preferable. In the present invention, the thickness of the rugged layer means the thickness of a portion where only the resin component of the rugged layer exists and no particles are present in the direction perpendicular to the substrate film. When two or more kinds of particles are contained, it is preferable that the film thickness of the uneven layer satisfies this formula for each of the particles contained.

The surface roughness Ra of one side having surface irregularities is preferably 0.2 μm or more and 2.5 μm or less. It is more preferably 0.4 μm or more and 2.0 μm or less. More preferably, it is 0.5 μm or more and 1.5 μm or less. If Ra is less than 0.2 μm, the 60° gloss tends to be high, and the transfer surface of the protective layer tends to have insufficient matte properties, which is not so preferable. On the other hand, if Ra exceeds 2.5 μm, the film thickness of the concavo-convex layer is increased as a result, and the productivity tends to be poor, which is not very preferable.

On one side of the unevenness transfer film of the present invention having surface unevenness, the rate of increase in 60° gloss after being pressurized at a pressure of 40MPa for 30 seconds is 25% or less of that before pressurization. preferable. If the rate of increase in 60° gloss after pressurization exceeds 25% of that before pressurization, indentations may remain during handling and may be transferred to the transfer surface of the protective layer, which may damage the appearance. In the pressurizing step, unevenness is reduced and the design of the surface to be transferred is lost, which is not preferable.

(Manufacture of transfer film)
Although the method for producing the transfer film of the present invention is not particularly limited, the uneven transfer film forms the uneven layer 12 by coating a base film with a coating composition containing particles for forming the uneven layer and curing the coating composition. It is preferable to manufacture by

This coating liquid can be applied to the substrate film by the following coating method, but is not limited to this method. Known methods such as reverse roll coating method, gravure coating method, kiss coating method, die coating method, roll brush method, spray coating method, air knife coating method, wire bar coating method, pipe doctor method, impregnation coating method and curtain coating method can be mentioned. be done. These methods can be applied singly or in combination.

When the resin of the coating composition is active energy ray-curable, the coating film after drying is irradiated with an active energy ray such as an ultraviolet ray or an electron beam. The drying temperature is preferably 40 to 100°C. Moreover, the time for passing through the drying oven is preferably 1 second or more and less than 60 seconds. Ultraviolet irradiation can be performed by a high-pressure mercury lamp, a fusion H lamp, a xenon lamp, or the like, and the irradiation dose of ultraviolet rays is preferably about 50 to 1000 mW/cm ² and a light intensity of about 50 to 1000 mJ/cm ² . On the other hand, the electron beam irradiation can be performed by an electron beam accelerator or the like, and the irradiation dose of the electron beam is preferably about 10 to 1000 krad.

When the resin of the coating composition is thermoplastic or thermosetting, the drying temperature is preferably 90 to 180°C, more preferably 100 to 160°C. Moreover, the time for passing through the drying oven is preferably 1 second or more and less than 60 seconds. The above range is preferable because thermal deformation of the substrate film can be suppressed and a film having an excellent appearance without wrinkles can be obtained.

(solvent)
The uneven layer-forming composition used in the present invention may contain an organic solvent for the purpose of improving workability during coating, controlling coating film thickness, and forming a mixed layer with the substrate film. Examples of organic solvents include alcohols such as isopropyl alcohol, methanol, and ethanol. ketones such as methyl ethyl ketone (MEK), methyl isobutyl ketone (MIBK) and cyclohexanone; Ethers such as tetrahydrofuran. esters such as methyl acetate, ethyl acetate and butyl acetate; aromatic hydrocarbons such as toluene and xylene; Or you may use these mixtures.

By using the uneven transfer film of the present invention to create, for example, an electromagnetic shielding film, the 60° gloss of the protective layer surface of the electromagnetic shielding film can be controlled to, for example, 5% or less, and designability can be imparted. can be done.

EXAMPLES In order to describe the present invention in detail, examples are given below, but the present invention is not limited to these examples. The evaluation methods used in the present invention are as follows.

(1) Measurement of Thickness of Concavo-convex Layer A cross-section of the obtained concavo-convex transfer film was cut in a direction perpendicular to the film using a microtome (LR-85, manufactured by Yamato Koki Co., Ltd.). The cut surface was observed with an optical microscope to measure the film thickness of the resin (A).

(2) Evaluation of 60° gloss After applying antireflection treatment to the back surface of the obtained uneven transfer film with black ink, the gloss value of the surface angle 60° was measured with a gloss meter (manufactured by Nippon Denshoku Industries, VG-2000). It was obtained by measuring using

(3) Evaluation of Surface Roughness of Concavo-convex Layer The arithmetic mean surface roughness (Ra; unit μm) of the surface of the concavo-convex layer of the obtained concavo-convex transfer film was measured using a laser microscope (manufactured by Keyence Corporation) in accordance with JIS B0601-2001. , VK-X110). Measurement conditions and analysis conditions were obtained as follows.
(Measurement condition)
The uneven layer surface was measured using a laser beam under the following conditions to obtain height data.
Objective lens: 50x Measurement mode: "Surface shape" for shape measurement
Measurement size: standard (1024 x 768)
Measurement quality: high accuracy (pitch 0.02 μm)
(analysis conditions)
Using VK-Analyzer (manufactured by KEYENCE CORPORATION), the line roughness was measured according to JIS B0601-2001 after surface tilt correction (automatic) for the obtained height data. Ten arbitrary points were measured and the average value was defined as Ra.

(4) Evaluation of Unevenness Stability The unevenness transfer film thus obtained was sandwiched between stainless steel plates, and pressed at a pressure of 40 MPa for 30 seconds using a pressing machine (10 Ton Press, manufactured by Riken Seiki). The 60° gloss and surface roughness of the uneven layer of the sample after pressurization were measured, and the amount of change from before pressurization was calculated and used as an index of unevenness stability. Also, the presence or absence of indentations in the pressure-pressing part was visually confirmed (○: no indentations, ×: with indentations).
(Rate of increase in 60° gloss after pressurization) (%)
= 100 x {(60°gross after pressurization) - (60°gross before pressurization)}/(60°gross before pressurization)

(5) Surface free energy A contact angle meter ( Measured using a fully automatic contact angle meter DM-701) manufactured by Kyowa Interface Science Co., Ltd. The contact angle used for the calculation was the contact angle 10 seconds after dropping each liquid.
The obtained contact angle data is calculated from the "Kitazaki-Hata" theory to obtain the dispersion component γsd, the polar component γsp, and the hydrogen bond component γsh of the surface free energy of the concavo-convex transfer film. and This calculation was performed using the calculation software in this contact angle meter software (FAMAS).

(6) Transferability of protective layer The following composition for forming a protective layer was applied onto the uneven transfer film with a wire bar of #10 and dried at 160°C for 30 seconds. After curing the protective layer, the laminate was heat-treated at 170° C. for 30 minutes. After that, a cyanoacrylate adhesive (Toagosei Co., Ltd., Aron Alpha (registered trademark)) was applied on the protective layer, and a polyester film with an easy-adhesion layer (Toyobo Co., Ltd., Cosmoshine (registered trademark) A4100, thickness: 125 μm) was applied. After laminating and adhering the easy-adhesive surface of No. 2, a rectangle having a width of 25 mm and a length of 150 mm was cut out, and peelability was evaluated when the concavo-convex transfer film was peeled off at a peeling angle of 180 degrees. The evaluation criteria were as follows.
◯: All the protective layer on the release layer was peeled off.
Δ: Part of the protective layer remained on the release layer.
x: Most of the protective layer remained on the release layer.
(Composition for forming protective layer)
・Toluene: 16.7% by mass
・Methyl ethyl ketone: 56.7% by mass
・Acrylic resin (UC-3000/manufactured by Toagosei Co., Ltd. (solid content: 100% by mass)): 10.0% by mass
・Methylated melamine resin (Nikalac MS-001/manufactured by Sanwa Chemical Co., Ltd. (solid content 60% by mass)): 16.7% by mass

(7) Designability of transfer surface The designability of the transferred surface of the protective layer was evaluated according to the following criteria. Those that cannot be transcribed are indicated as -.
○: When the 60° gloss of the transferred surface of the protective layer is 5% or less △: When the 60° gloss of the transferred surface of the protective layer is greater than 5% and 10% or less ×: Transferred surface of the protective layer If the 60° gloss of is greater than 10%

The resin was adjusted as follows.

(Olefin resin 1)
750 mL of 4-methyl-1-pentene and 0.75 mL of a 1.0 mmol/ml toluene solution of triisobutylaluminum were introduced into a 1.5 L stirrer-equipped autoclave under nitrogen and stirred. Next, the mixture was heated to 60° C. and pressurized with propylene to a gauge pressure of 0.12 MPa. Next, 1 mmol (in terms of Al) of methylaminoxane prepared in advance, diphenylmethylene(1-ethyl-3-t-butyl-cyclopentadienyl)(2,7-di-t-butyl-fluorenyl)zirconium dichloride 0.34 ml of a toluene solution containing 0.005 mmol of was pressurized into the autoclave under nitrogen to initiate the polymerization reaction. During the polymerization reaction, the temperature was adjusted so that the internal temperature of the autoclave was 60°C. One hour after the start of the polymerization, 5 ml of methanol was injected into the autoclave with nitrogen to stop the polymerization, and the autoclave was returned to the atmospheric pressure. After that, acetone was added to the reaction solution while stirring, and the resulting solvent-containing powdery polymer was dried at 130° C. under reduced pressure for 12 hours. The resulting polymer weighed 34.7 g and had a 4-methyl-1-pentene content of 94 mol % and a propylene content of 6 mol %. The melting point (Tm) of the polymer was 200°C.
The obtained polymethylpentene polymer was dissolved in methylcyclohexane so that the solid content was 15% by mass.

(Example 1)
A composition for forming an uneven layer was applied to the easy-adhesion layer side surface of a polyester film with an easy-adhesion layer (manufactured by Toyobo Co., Ltd., Cosmoshine (registered trademark) A4300, thickness: 50 μm) as a base film with a wire bar #14. It was applied and dried at 160° C. for 30 seconds to form a concavo-convex layer and obtain a concavo-convex transfer film.
Coating liquid 1 below was used as a composition for forming an uneven layer.
(Coating liquid 1)
・Toluene: 65.0% by mass
・ Tetrahydrofuran: 20.0% by mass
・ Cyclic olefin resin (ARTON (registered trademark) G7810/manufactured by JSR (solid content: 100% by mass)): 10.0% by mass
・ PMMA particles (Eposter (registered trademark) MA1002, average particle size 2.5 μm / manufactured by Nippon Shokubai Co., Ltd.): 5.0% by mass
The resulting release film was evaluated for surface free energy, heat-resistant peelability, 60° gloss, and unevenness stability. The 60° gloss of the surface to be transferred of the obtained protective layer was also evaluated.

(Example 2)
A concavo-convex transfer film was prepared and evaluated in the same manner as in Example 1, except that the coating liquid 2 was used.
(Coating liquid 2)
・Toluene: 60.0% by mass
・ Tetrahydrofuran: 20.0% by mass
・ Cyclic olefin resin (ARTON (registered trademark) G7810/manufactured by JSR (solid content: 100% by mass)): 10.0% by mass
・ PMMA particles (Eposter (registered trademark) MA1002, average particle size 2.5 μm / manufactured by Nippon Shokubai Co., Ltd.): 5.0% by mass
・Modified organic polymer particles (CERAFLOUR (registered trademark) 1000, average particle size 5.0 μm / manufactured by BYK-Chemie Japan): 5.0% by mass

(Example 3)
A concavo-convex transfer film was prepared and evaluated in the same manner as in Example 1, except that the coating liquid was changed to 3.
(Coating liquid 3)
・Toluene: 22.33% by mass
・ Olefin resin 1 (solid content 15% by mass)): 66.67% by mass
- Isocyanate cross-linking agent (Takenate D120N/manufactured by Mitsui Chemicals): 1.00% by mass
・ PMMA particles (Eposter (registered trademark) MA1002, average particle size 2.5 μm / manufactured by Nippon Shokubai Co., Ltd.): 5.0% by mass
・Modified organic polymer particles (CERAFLOUR (registered trademark) 1000, average particle size 5.0 μm / manufactured by BYK-Chemie Japan): 5.0% by mass

(Example 4)
A concavo-convex transfer film was prepared and evaluated in the same manner as in Example 1, except that the coating liquid 4 was used.
(Coating liquid 4)
・Toluene: 32.43% by weight
・Methyl ethyl ketone: 32.42% by mass
・ Amino alkyd resin (Tesfine 322, solid content 40% by mass, manufactured by Hitachi Chemical Co., Ltd.): 25.00% by mass
・ Curing catalyst (Dryer 900 / manufactured by Hitachi Chemical Co., Ltd.): 0.15% by mass
・ PMMA particles (Eposter (registered trademark) MA1002, average particle size 2.5 μm / manufactured by Nippon Shokubai Co., Ltd.): 5.0% by mass
・Modified organic polymer particles (CERAFLOUR (registered trademark) 1000, average particle size 5.0 μm / manufactured by BYK-Chemie Japan): 5.0% by mass

(Comparative example 1)
A sand matte film (Type D manufactured by Kaisei Kogyo Co., Ltd.) obtained by sandblasting a polyester film was used as the uneven transfer film. As a result of evaluating the 60° gloss, surface roughness, and unevenness stability against pressure, the surface unevenness was reduced by pressing, and indentations were visually confirmed, and the 60° gloss increased and the surface roughness Ra decreased. The result was remarkable.

(Comparative example 2)
A concavo-convex transfer film was prepared and evaluated in the same manner as in Example 1, except that the coating liquid 15 was used.
(Coating liquid 15)
・Toluene: 36.6% by mass
・Methyl ethyl ketone: 36.6% by mass
・Methylated melamine resin (Nikalac MS-001/manufactured by Sanwa Chemical Co., Ltd. (solid content 60% by mass)): 16.8% by mass
・ PMMA particles (Eposter (registered trademark) MA1002, average particle size 2.5 μm / manufactured by Nippon Shokubai Co., Ltd.): 5.0% by mass
・Modified organic polymer particles (CERAFLOUR (registered trademark) 1000, average particle size 5.0 μm / manufactured by BYK-Chemie Japan): 5.0% by mass

(Comparative Example 3)
A concavo-convex transfer film was prepared and evaluated in the same manner as in Example 1, except that the coating liquid 16 was used.
(Coating liquid 16)
・Toluene: 25.0% by mass
・Methyl ethyl ketone: 25.0% by mass
・ Polyamideimide resin (Vylomax (registered trademark) HR-15ET / manufactured by Toyobo Co., Ltd. (solid content 25% by mass)): 40.0% by mass
・ PMMA particles (Eposter (registered trademark) MA1002, average particle size 2.5 μm / manufactured by Nippon Shokubai Co., Ltd.): 5.0% by mass
・Modified organic polymer particles (CERAFLOUR (registered trademark) 1000, average particle size 5.0 μm / manufactured by BYK-Chemie Japan): 5.0% by mass

By using the concavo-convex transfer film of the present invention, for example, it is possible to efficiently provide an electromagnetic wave shielding film excellent in the matte appearance of the transferred surface of the protective layer.

Reference Signs List 1: Concavo-convex transfer film 2: Layer to be transferred 11: Base film 12: Concavo-convex layer 13: Release layer 14: Particles 21: Base film constituting the transferred body 22: Shield layer 23: Protective layer

Claims (5)

The film has an uneven layer on at least one side, the uneven layer is a coating layer containing a resin and particles, and the total value of the polar component (γsp) and the hydrogen bond component (γsh) of the surface free energy on the surface of the uneven layer is 5 mJ/m ² or less, and the 60° gloss of the uneven layer surface is 5% or less,
The uneven layer surface does not substantially contain a Si component,
The resin contained in the uneven layer contains at least one selected from the group consisting of cyclic polyolefin, polymethylpentene, acrylic resin, and aminoalkyd resin ,
The uneven layer contains organic particles,
Concave-convex transfer film for forming a protective layer for electronic device parts. One side of the film has an uneven surface, the 60° gloss of the surface having the uneven surface is 5% or less, and the increase rate of the 60° gloss after applying a pressure press of 40 MPa for 30 seconds is 2. The concavo-convex transfer film according to claim 1, wherein the gloss is 25% or less with respect to the 60° gloss before applying the pressurization. 3. The concavo-convex transfer film according to claim 1, wherein the concavo-convex layer surface has a surface roughness Ra of 0.2 μm or more and 2.5 μm or less. 4. Any one of claims 1 to 3, wherein the total amount of the particles contained in the uneven layer is 40% by mass or more and 200% by mass or less with respect to the entire resin composition serving as a binder component of the uneven layer. The concave-convex transfer film described above. The average particle size of the particles is 1 μm or more and 10 μm or less ,
5. The uneven transfer film according to claim 1 , wherein the particles are crosslinked organic particles .

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