TW201446924A - Adhesive sheet - Google Patents

Abstract

The present invention provides an adhesive sheet capable of rendering the desired color, and making a fingerprint inconspicuous on the back surface of an adhesive sheet. The adhesive sheet (30) according to the present invention includes: a base layer (10), a colored layer (2) laminated on a main surface of the base layer (10), an anti fingerprint treated layer (1) laminated on the colored layer (2), and an adhesive layer (5) laminated on the main surface of the base layer (10) that is opposite to the colored layer (2), and the base layer (10) contains a plastic layer (3) and a metal layer (4). The surface mean waviness (Wa) and average roughness (Ra) of the anti fingerprint treated layer (1) that is opposite to the colored layer (2) are 150A or more, and 2000A or more, respectively. Preferably, said adhesive layer comprises acrylic polymer using (methyl) acrylic acid alkyl ester as the main monomer component, and said plastic layer is a polyethylene terephthalate layer.

Description

Adhesive film

The present invention relates to an adhesive sheet.

As a conventional adhesive sheet, it is known that a single-layer layer of a substrate containing a plastic material has an adhesive layer. The above-mentioned adhesive sheet is widely used as a bonding material in various industrial fields such as writers' electric products, automobiles, and building materials. The use of adhesive sheets has expanded, and the use of adhesive sheets at the places where they are seen has also increased.

On the other hand, a matte powder coating adhered to the surface of a steel sheet is known (for example, see Patent Document 1). The powder coating is not easy to adhere to fingerprint marks, and the design is also excellent.

[Previous Technical Literature] [Patent Literature]

[Patent Document 1] Japanese Patent Laid-Open No. Hei 10-306237

It is sometimes required that the adhesive sheets used in the above-mentioned places are not easily attached to fingerprint marks. In this case, as described in Patent Document 1, a matting paint containing a coloring agent is applied to the surface.

However, in the case of the above coatings, the colorant is diluted by the matte coating. Therefore, an adhesive sheet having a surface coated with the above-mentioned matting paint sometimes cannot obtain desired color development characteristics.

The present invention has been made in view of the above problems, and an object thereof is to provide an adhesive sheet which can develop a desired color and which makes the fingerprint difficult to be noticeable on the back surface of the adhesive sheet.

In order to solve the above problems, the inventors conducted intensive studies. As a result, it has been found that by separately providing the colored layer and the fingerprint-resistant layer and forming the surface of the fingerprint-resistant layer into a specific shape, it is possible to realize an adhesive sheet which can develop a color to a desired color and which makes the fingerprint difficult to be visible on the back side of the adhesive sheet. The present invention has thus been completed.

That is, the adhesive sheet of the present invention comprises: a base layer; a colored layer laminated on one main surface of the base layer; a fingerprint-resistant layer laminated on the colored layer; and a laminated layer on the base layer opposite to the colored layer Adhesive layer on the main surface of the side. Here, the base material layer includes a plastic layer and a metal layer, and a surface of the surface of the anti-fingerprint treatment layer opposite to the colored layer has a Wa of 150 Å or more and Ra of 2000 Å or more.

In the pressure-sensitive adhesive sheet of the present invention, it is preferred that the pressure-sensitive adhesive layer contains an acrylic polymer having a (meth)acrylic acid alkyl ester as a monomer main component.

Further, in the adhesive sheet of the present invention, it is preferable that the plastic layer is a polyethylene terephthalate layer.

Further, in the adhesive sheet of the present invention, it is preferable that the metal layer is an aluminum layer.

The adhesive sheet of the present invention can develop color to a desired color, and makes the fingerprint difficult to be noticeable on the back side of the adhesive sheet.

1‧‧‧Fingerprint resistant layer

2‧‧‧Colored layer

3‧‧‧Plastic layer

4‧‧‧metal layer

5‧‧‧Adhesive layer

10‧‧‧Substrate layer

30‧‧‧Adhesive tablets

Fig. 1 is a cross-sectional view showing a schematic configuration of an example of an adhesive sheet of the embodiment.

Hereinafter, an embodiment of the present invention will be specifically described based on Fig. 1 .

Fig. 1 is a cross-sectional view showing a schematic configuration of an example of an adhesive sheet 30 of the present embodiment. As shown in FIG. 1, the adhesive sheet 30 includes a base material layer 10, a coloring layer 2 laminated on one main surface of the base material layer 10, a fingerprint-resistant layer 1 laminated on the colored layer 2, and a laminated layer on the base material layer 10. The adhesive layer 5 on the main surface opposite to the coloring layer 1. Furthermore, in this specification "Piece" also includes the meaning of "film" or "belt". In the present specification, the term "main surface" means the surface or the back surface of a layer such as a base material layer. That is, the "surface" of the above layer used in the sense of being distinguished from the end face. Hereinafter, each layer will be described.

I. Substrate layer

The substrate layer 10 includes a plastic layer 3 and a metal layer 4.

The plastic layer 3 is obtained, for example, by molding various plastic materials into a film shape or a sheet shape. The plastic material is not particularly limited, and examples thereof include polyesters such as polyethylene terephthalate and polybutylene terephthalate, polyolefins such as polyethylene and polypropylene, and polyimine and polyfluorene. Amine, polycarbonate, etc.

The plastic layer 3 may be transparent or may be colored by adding a pigment such as carbon black.

The thickness of the plastic layer 3 is not particularly limited. For example, it is preferably more than 0 μm and 300 μm or less, more preferably 1 μm to 100 μm, still more preferably 3 μm to 50 μm, and particularly preferably 5 μm to 25 μm.

The metal layer 4 is produced by forming various metal materials into a film shape or a sheet shape, or by vapor deposition on the plastic layer 3. The metal material is not particularly limited, and examples thereof include aluminum, iron, nickel, gold, silver, copper, platinum, stainless steel, titanium, and tin, and the like.

The thickness of the metal layer 4 is not particularly limited, and is, for example, more than 0 μm and preferably 100 μm or less, more preferably 1 to 50 μm, still more preferably 3 μm to 20 μm, and particularly preferably 5 μm to 15 μm.

The base material layer 10 can be formed by laminating the plastic layer 3 and the metal layer 4. The layer configuration of the substrate layer 10 is not limited to the configuration shown in FIG. 1, and may be set to, for example, a layer structure of a plastic layer/metal layer, a layer structure of a metal layer/plastic layer/metal layer, and a plastic layer/metal layer/plastic layer. Layer composition, metal layer / plastic layer / metal layer / plastic layer layer.

Further, on the surface of the base material layer 10, an appropriate surface treatment can be carried out as needed. The surface treatment can be, for example, a chemical or physical treatment to increase the adhesion to adjacent materials, such as the adhesive layer. As an example of the surface treatment, corona discharge treatment, chromium Acid treatment, exposure to ozone, exposure to flame, ultraviolet irradiation treatment, plasma treatment, coating of primer (primer), and the like.

The thickness of the base material layer 10 is not particularly limited, and is, for example, preferably more than 0 μm and 400 μm or less, more preferably 2 μm to 150 μm, still more preferably 6 μm to 70 μm, and particularly preferably 10 μm to 40 μm.

II. Colored layer

The colored layer 2 is laminated on one main surface of the substrate layer 10. The colored layer 2 is, for example, a colored printed layer formed by printing various inks such as black ink on the base material layer 10. The colored layer 2 can be formed by a method such as gravure printing or screen printing. The color of the colored layer 2 can be appropriately changed to white, yellow, blue, red, green, or the like depending on the purpose of use, in addition to black.

The thickness of the colored layer 2 is preferably, for example, more than 0 μm and 5 μm or less, more preferably 0.3 μm to 5 μm, still more preferably 0.5 μm to 5 μm, particularly preferably 0.6 μm to 3 μm, and most preferably 0.8 μm to 2 μm.

III. Adhesive layer

The adhesive layer 5 is laminated on the base material layer 10 (on the main surface of the base material layer 10 on the side opposite to the surface contacting the colored layer 2).

The adhesive layer 5 is not particularly limited, and various adhesives such as an acrylic adhesive, a rubber adhesive, and a polyoxygen adhesive can be used. Among them, an acrylic adhesive containing an acrylic polymer is preferably used. .

The acrylic polymer may, for example, be obtained by polymerizing a monomer composition containing an alkyl (meth)acrylate (for example, solution polymerization, emulsion polymerization, or UV polymerization).

In the present specification, the alkyl (meth)acrylate means an alkyl acrylate and/or an alkyl methacrylate, and "(meth)"" has the same meaning.

The content of the acrylic polymer in the acrylic adhesive is not particularly limited. The system is usually 50% by weight or more, preferably 60 to 100% by weight, and more preferably 70 to 95% by weight.

The alkyl (meth)acrylate is preferably 50% by weight or more and 99.9% by weight or less, more preferably 60% by weight or more and 95% by weight or less based on the total amount of the monomer components for preparing the acrylic polymer. Further, it is more preferably 70% by weight or more and 93% by weight or less.

Examples of the alkyl (meth)acrylate include methyl (meth)acrylate, ethyl (meth)acrylate, propyl (meth)acrylate, and isopropyl (meth)acrylate. Butyl acrylate, isobutyl (meth)acrylate, second butyl (meth)acrylate, tert-butyl (meth)acrylate, amyl (meth)acrylate, isoamyl (meth)acrylate Ester, hexyl (meth) acrylate, heptyl (meth) acrylate, octyl (meth) acrylate, 2-ethylhexyl (meth) acrylate, isooctyl (meth) acrylate, (methyl) ) decyl acrylate, isodecyl (meth) acrylate, decyl (meth) acrylate, isodecyl (meth) acrylate, undecyl (meth) acrylate, dodecane (meth) acrylate Base ester, tridecyl (meth)acrylate, tetradecyl (meth)acrylate, pentadecyl (meth)acrylate, cetyl (meth)acrylate, (methyl) a heptadecyl acrylate, octadecyl (meth) acrylate, pentadecyl (meth) acrylate, eicosyl (meth) acrylate, etc. having an alkyl group having 1 to 20 carbon atoms The alkyl (meth)acrylate. The alkyl (meth)acrylate having an alkyl group having 2 to 10 carbon atoms is preferable, and an alkyl (meth)acrylate having an alkyl group having 3 to 8 carbon atoms is more preferable. These alkyl (meth)acrylates may be used singly or in combination of two or more.

Further, the acrylic polymer may contain other monomer components (copolymerizable monomers) copolymerizable with the alkyl (meth)acrylate, if necessary. As the copolymerizable monomer, a monomer having a polar group can be preferably used.

Specific examples of the copolymerizable monomer include carboxyl groups such as acrylic acid, methacrylic acid, carboxyethyl acrylate, carboxy amyl acrylate, itaconic acid, maleic acid, fumaric acid, crotonic acid, and isocrotonic acid. Monomer; hydroxyethyl (meth)acrylate, hydroxypropyl (meth)acrylate, hydroxybutyl (meth)acrylate, hydroxyhexyl (meth)acrylate, hydroxyoctyl (meth)acrylate, (A) a hydroxyl group-containing monomer such as hydroxy decyl acrylate, hydroxylauryl (meth) acrylate, hydroxyalkyl (meth) acrylate such as methyl 4-hydroxymethylcyclohexyl methacrylate; maleic anhydride; An acid anhydride group-containing monomer such as itaconic anhydride; styrenesulfonic acid, allylsulfonic acid, 2-(methyl)acrylamido-2-methylpropanesulfonic acid, (meth)acrylamidamine propanesulfonic acid, a sulfonic acid group-containing monomer such as sulfopropyl (meth)acrylate, (meth)acryloxynaphthalenesulfonic acid or sodium vinylsulfonate; a phosphate-containing monomer such as 2-hydroxyethylpropenyl phosphate (meth)acrylamide, N,N-dimethyl(meth)acrylamide, N,N-diethyl(meth)acrylamide, N-isopropyl(methyl)propene oxime Amine, N-butyl ( Acrylamide, N-methylol (meth) acrylamide, N-methylolpropane (meth) acrylamide, N-methoxymethyl (meth) acrylamide, N- (N-substituted) guanamine monomer such as butoxymethyl (meth) acrylamide; N-(methyl) propylene oxymethylene succinimide, N-(methyl) propylene oxime Amber quinone imine monomer such as -6-oxyhexamethylene succinimide, N-(methyl) propylene decyl-8-oxyhexamethylene succinimide; N-cyclohexyl Maleic imine, such as maleic imine, N-isopropylmaleimide, N-lauryl maleimide, N-phenylmaleimide, etc.; N-methyl Yikang imine, N-ethyl itaconimine, N-butyl itaconimine, N-octyl ketimine, N-2-ethylhexyl ketimine, N - cyclohexyl ketimine, N-lauryl ketamine, and the like; vinyl acetate, vinyl acetate and other vinyl esters; N-vinyl-2-pyrrole Pyridone, N-methylvinylpyrrolidone, N-vinylpyridine, N-vinylpiperidone, N-vinylpyrimidine, N-vinylpiperidone N-vinylpyrene , N-vinylpyrrole, N-vinylimidazole, N-vinyl Azole, N-(methyl)propenyl-2-pyrrolidone, N-(methyl)propenylpyridinium, N-(methyl)propenylpyrrolidine, N-vinyl a nitrogen-containing heterocyclic monomer such as a phenyl group; an N-vinyl carboxamide; an internal guanamine monomer such as N-vinyl caprolactam; a cyanoacrylate monomer such as acrylonitrile or methacrylonitrile; (amino)ethyl (meth) acrylate, N,N-dimethylaminoethyl (meth) acrylate, tert-butylaminoethyl (meth) acrylate, etc. Ester monomer; (meth)acrylic acid alkoxyalkyl ester monomer such as methoxyethyl (meth)acrylate or ethoxyethyl (meth)acrylate; styrene, α-methylbenzene a styrene monomer such as ethylene; an epoxy group-containing acrylic monomer such as glycidyl (meth)acrylate; polyethylene glycol (meth) acrylate, polypropylene glycol (meth) acrylate, methoxy B a diol-based acrylate monomer such as a diol (meth) acrylate or a methoxypolypropylene glycol (meth) acrylate; or an acrylate-based monomer having a hetero ring such as a tetrahydrofurfuryl (meth) acrylate; a vinyl ether monomer such as a vinyl alkyl ether such as methyl vinyl ether or ethyl vinyl ether; thioglycolic acid; an aromatic vinyl compound such as styrene or vinyl toluene; An olefin or a diene such as a olefin, an isoprene or an isobutylene; a vinyl chloride; an isocyanate group-containing monomer such as 2-isocyanate ethyl (meth)acrylate; a (meth) acrylate having a fluorine atom; (meth) acrylate; and the like. Further, these copolymerizable monomers may be used alone or in combination of two or more.

When the acrylic polymer contains the above-mentioned copolymerizable monomer, a hydroxyl group-containing monomer or a carboxyl group-containing monomer can be preferably used. The amount of the copolymerizable monomer to be used is not particularly limited, and it is usually 0.1 to 30% by weight, preferably 0.5 to 20% by weight, based on the total amount of the monomer components for preparing the acrylic polymer. Preferably, it is 1 to 15% by weight of a copolymerizable monomer.

By containing 0.1% by weight or more of the copolymerizable monomer, the cohesive force of the adhesive sheet can be prevented from being lowered, and high shearing force can be obtained. In addition, by setting the content of the copolymerizable monomer to 30% by weight or less, the cohesive force can be prevented from being excessively high, and the feeling of contact at normal temperature (25 ° C) can be improved.

Further, in order to adjust the cohesive force of the formed adhesive layer 5, the acrylic polymer may contain a polyfunctional monomer as needed. Examples of the polyfunctional monomer include (poly)ethylene glycol di(meth)acrylate, (poly)propylene glycol di(meth)acrylate, neopentyl glycol di(meth)acrylate, and pentaerythritol. Di(meth)acrylate, pentaerythritol tri(meth)acrylate, dipentaerythritol hexa(meth)acrylate, 1,2-ethanediol di(meth)acrylate, 1,6-hexanediol (meth) acrylate, 1,12-dodecanediol di(methyl) propyl Ethyl ester, trimethylolpropane tri(meth)acrylate, tetramethylol methane tri(meth)acrylate, allyl (meth)acrylate, vinyl (meth)acrylate, divinyl Benzene, epoxy acrylate, polyester acrylate, urethane acrylate, butyl (meth) acrylate, hexyl (meth) acrylate, and the like. Among them, trimethylolpropane tri(meth)acrylate, hexanediol di(meth)acrylate, dipentaerythritol hexa(meth)acrylate can be preferably used. The polyfunctional (meth) acrylate may be used singly or in combination of two or more.

The amount of the polyfunctional monomer to be used varies depending on the molecular weight, the number of functional groups, and the like, and is 0.01 to 3.0% by weight, preferably 0.02 to 2.0% by weight based on the total of the monomer components for preparing the acrylic polymer. %, more preferably 0.03 to 1.0% by weight.

When the cohesive force is adjusted, a crosslinking agent may be used in addition to the above polyfunctional monomer. The crosslinking agent can be used by a typical user. Examples of the crosslinking agent include an epoxy crosslinking agent, an isocyanate crosslinking agent, and a polyfluorene crosslinking agent. An oxazoline crosslinking agent, an aziridine crosslinking agent, a decane crosslinking agent, an alkyl etherified melamine crosslinking agent, a metal chelate crosslinking agent, and the like. It is particularly preferable to use an isocyanate crosslinking agent or an epoxy crosslinking agent.

Specific examples of the isocyanate crosslinking agent include toluene diisocyanate, hexamethylene diisocyanate, isophorone diisocyanate, benzene dimethylene diisocyanate, and hydrogenated benzene dimethylene diisocyanate. , diphenylmethane diisocyanate, hydrogenated diphenylmethane diisocyanate, tetramethylbenzene dimethylene diisocyanate, naphthalene diisocyanate, triphenylmethane triisocyanate, polymethylene polyphenyl isocyanate, and the like An adduct of a polyol such as trimethylolpropane.

Examples of the epoxy-based crosslinking agent include bisphenol A, epichlorohydrin epoxy resin, ethyl diglycidyl ether, polyethylene glycol diglycidyl ether, glycerol diglycidyl ether, and glycerol triglycidyl alcohol. Ether, 1,6-hexanediol glycidyl ether, trimethylolpropane triglycidyl ether, diglycidylaniline, N,N,N',N'-tetraglycidyl metaxylylenediamine and 1 , 3-bis(N,N'-diglycidylaminomethyl)cyclohexane or the like.

Various additives can be added to the adhesive. Examples of the above-mentioned additives include tackifiers such as rosin derivative resins, polyterpene resins, petroleum resins, and oil-soluble phenol resins; plasticizers; fillers; anti-aging agents; surfactants; and pigments (colorants). Wait.

The method of forming the adhesive layer is not particularly limited. For example, it can be formed by applying an adhesive to a suitable support such as a spacer (release liner) or a substrate to form an adhesive layer, and thereafter, according to Drying or curing (curing with heat or active energy rays) is required. Further, when active energy ray curing (photocuring) is performed, since the photopolymerization reaction is inhibited by oxygen in the air, it is preferable to apply a spacer (release liner) or a substrate to the adhesive layer. The support is subjected to photocuring or the like under a nitrogen atmosphere to isolate oxygen. The appropriate support used in forming the adhesive layer can be peeled off at an appropriate period when the adhesive sheet is formed, or can be peeled off when the adhesive sheet is produced.

The thickness of the adhesive layer can be appropriately selected depending on the purpose of use of the adhesive sheet, and is, for example, more than 0 μm and 300 μm or less, preferably 1 to 200 μm, further preferably 2 to 50 μm, and particularly preferably about 2 to 10 μm.

IV. Fingerprint resistant layer

The fingerprint-resistant layer 1 is laminated on the surface of the colored layer 2.

The fingerprint-resistant layer 1 is not particularly limited, and can be formed, for example, by coating a coating material described in Japanese Laid-Open Patent Publication No. Hei 10-306237. Among the above coating materials, a nitrogen-containing component such as an adipate such as ethyl adipate or an isophorone diisocyanate is more preferred. The same applies to the embodiment described later.

The thickness of the fingerprint-resistant layer 1 is not particularly limited. For example, it is preferably more than 0 μm and 2 μm or less, more preferably 0.4 to 2 μm, still more preferably 0.6 to 1.4 μm, and particularly preferably 0.8 to 1.2 μm. The same applies to the embodiment described later. The outer surface of the anti-fingerprint layer 1 opposite to the coloring layer 2 is subjected to fingerprinting resistance. In a preferred embodiment, Wa is 150 Å or more and Ra is 2000 Å or more. Here, Wa means an arithmetic mean waviness indicating a reference length (a contour curve extracted for calculating a surface roughness or a waviness component) The average of the absolute values of the contour curve.

Further, Wa and Ra on the outer surface of the fingerprint-resistant layer 1 can be evaluated using a surface shape measuring device (name: P-11 (manufactured by Tencor)). The above Wa is preferably 200 Å or more, more preferably 250 Å or more, further preferably 300 Å or more, and particularly preferably 350 Å or more. The upper limit is not particularly limited and may be set to 1000 Å or less, preferably 900 Å or less, and more preferably 800 Å or less. Further, the above Ra is preferably 2100 Å or more. The upper limit is not particularly limited and may be set to 5,000 Å or less, preferably 4,000 Å or less, and more preferably 3,000 Å or less.

The Wa or Ra of the surface of the fingerprint-resistant layer 1 can be adjusted to the above range by appropriately adjusting the coating speed of the fingerprint-resistant layer, the number of coatings, drying conditions, and the like.

According to the adhesive sheet 30 described above, the colored layer 2 is not exposed on the surface, and the fingerprint-resistant layer 1 is exposed on the surface, so that the colored layer 2 is protected. Further, when the finger touches the back surface of the fingerprint-resistant adhesive sheet, the fingerprint can be made difficult by the fingerprint-resistant layer 1. Further, since the colored layer 2 and the fingerprint-resistant layer 1 are provided separately, the color development property and the fingerprint resistance of the adhesive sheet 30 are also achieved.

In particular, in the case where the colored layer is black, the light-shielding effect of the colored layer makes it difficult to visually recognize the adherend, and when the finger touches the back surface of the fingerprint-resistant adhesive sheet, the fingerprint-resistant layer can be used. Fingerprints are difficult to notice. As a result, the design of the article including the adherend followed by the adhesive sheet can be improved.

In order to express the above effects, the fingerprint-resistant layer 1 is preferably transparent. Specifically, the transmittance (typically, the total light transmittance in the visible light wavelength region) is preferably 70% or more, more preferably 80% or more, still more preferably 90% or more.

Further, the surface of the anti-fingerprint layer on the back surface of the substrate (the surface on the side opposite to the side of the adhesive layer) may be subjected to a mold release treatment as needed (for example, a general polyoxyl system, a long-chain alkyl group, The fluorine-based release treatment agent is typically treated in the form of a film of about 0.01 μm to 1.0 μm. By performing the mold release treatment, it is possible to obtain an effect of easily unwinding the adhesive tape wound in a roll shape. Among them, in terms of excellent peeling performance, it is preferred to use poly The mold release treatment is carried out by a deuterium-based mold release treatment agent.

V. Adhesive sheet

The total thickness of the adhesive sheet of the present embodiment is not particularly limited, but is preferably 5 to 500 μm, more preferably 10 to 300 μm, still more preferably 15 to 100 μm, and particularly preferably 20 to 50 μm.

VI. Release liner

The adhesive sheet disclosed herein may be in the form of a release liner adhesive sheet having a release liner disposed on the surface of the adhesive layer. As the release liner, a conventional release paper or the like can be used, and it is not particularly limited. For example, a release liner for a surface of a substrate such as a plastic film or paper having a release-treated layer, a fluorine-containing polymer (such as polytetrafluoroethylene) or a polyolefin resin (polyethylene, polypropylene, etc.) can be used. Release liners for materials, etc. The release treatment layer may be formed by subjecting the substrate to a surface treatment by a release treatment agent such as a polyfluorene-based, long-chain alkyl-based, fluorine-based or molybdenum sulfide.

The adhesive sheet of this embodiment can be used for various purposes previously known. The adhesive sheet of the present embodiment is provided with a metal layer and is excellent in electromagnetic shielding property and electrical conductivity. Therefore, it can be preferably used as an adhesive sheet for various electronic devices. More specifically, it can be used for sheets for electromagnetic shielding, sheets for antistatic (antistatic sheets), and the like. Further, since the pressure-sensitive adhesive sheet of the present embodiment is provided with the fingerprint-resistant layer and the coloring layer, it has high design properties, and in particular, it can be preferably used for a conspicuous position on the surface of an electronic device.

That is, another preferred embodiment of the present invention includes a laminate of the above-mentioned adhesive sheet and an electronic device.

[Examples]

Hereinafter, the present invention will be described in detail based on examples, but the present invention is not limited by the examples. In the present embodiment, "parts" means "parts by weight" unless otherwise specified, and is a solid content standard unless otherwise specified.

(Production of adhesive composition)

Using 0.08 parts of 2,2-azobisisobutyronitrile as a polymerization initiator, 70 parts of butyl acrylate, 30 parts of 2-ethylhexyl acrylate, 3 parts of acrylic acid and 0.05 parts of 4-hydroxyethyl acrylate The solution polymerization was carried out for 6 hours in a mixed solution of toluene and ethyl acetate [toluene/ethyl acetate (weight ratio) = 1/1] to obtain an acrylic polymer having a weight average molecular weight of 500,000. To 100 parts of the acrylic polymer, 30 parts of a polymerized rosin pentaerythritol ester resin (trade name "PENSEL D125", manufactured by Arakawa Chemical Industry Co., Ltd., softening point: 125 ° C) and 3 parts of an isocyanate crosslinking agent (trade name) were added. "Coronate L" (manufactured by Nippon Polyurethane Industry Co., Ltd.) was stirred and mixed to prepare an adhesive.

(Example 1)

Printing on a whole surface of a PET (polyethylene terephthalate) film (transparent) having a thickness of 12 μm using black ink (once of printing), forming a color layer having a thickness of 1 μm, and further printing by gravure on the side of the colored layer Stacked fingerprint resistant layer. On the non-printing surface of the printed PET film, an aluminum foil (9 μm) was laminated by dry lamination to prepare a composite substrate. An acrylic adhesive layer (thickness: 4 μm) was formed on the entire aluminum surface of the composite substrate using the above-mentioned adhesive. Thus, the adhesive sheet (the fingerprint-resistant adhesive sheet) of Example 1 was produced. The adhesive sheet has a layer structure including a fingerprint-resistant layer/colored layer/PET film/aluminum foil/acrylic adhesive layer. The total thickness of the adhesive sheet was 30 μm.

(Reference example 1)

Printing was performed using black ink on one entire surface of a PET film (transparent) having a thickness of 12 μm (once of printing), and a coloring layer having a thickness of 1 μm was formed. An acrylic pressure-sensitive adhesive layer (thickness: 23 μm) was formed on the colored layer using the above-mentioned adhesive. Further, a fingerprint-resistant layer was laminated on the other surface of the PET film by gravure printing. Thus, the adhesive sheet (fingerprint-resistant adhesive sheet) of Reference Example 1 was produced. The adhesive sheet has a layer structure including a fingerprint-resistant layer/PET film/colored layer/acrylic adhesive layer.

(Reference example 2)

An adhesive sheet of Reference Example 2 was produced in the same manner as in the adhesive sheet of Reference Example 1, except that the anti-fingerprint layer was laminated on the colored layer side and the acrylic pressure-sensitive adhesive layer was formed on the PET film side. The adhesive sheet of Reference Example 2 has a layer structure including an acrylic pressure-sensitive adhesive layer/PET film/colored layer/fingerprint resistant layer.

(Reference Example 3)

A PET film (transparent) having a thickness of 4 μm was used as a PET film, and a coloring layer was formed by printing with a gray ink (once of printing), and the adhesion of Reference Example 3 was produced in the same manner as in the adhesive sheet of Reference Example 1. sheet. The adhesive sheet of Reference Example 3 had a layer structure including a fingerprint-resistant layer/PET film/colored layer/acrylic adhesive layer as in Reference Example 1.

(Comparative Example 1)

The adhesive sheet of Comparative Example 1 was produced in the same manner as the adhesive sheet of Reference Example 1, except that the fingerprint-resistant layer was not formed. That is, the back surface of the adhesive sheet of Comparative Example 1 was the outer surface of the PET film.

(Comparative Example 2)

An adhesive sheet of Comparative Example 2 was produced in the same manner as the adhesive sheet of Reference Example 2 except that the fingerprint-resistant layer was not formed. That is, the back surface of the adhesive sheet of Comparative Example 2 was the outer surface of the colored layer.

For the adhesive sheets of the respective examples and the comparative examples, Ra and Wa were evaluated using a surface shape measuring device (product name: P-11, manufactured by Tencor Co., Ltd.). The evaluation results of Ra and Wa are shown in Table 1.

(print resistance)

The finger touched the back surface of each of the reference examples and the adhesive sheets of the comparative examples, and the case where the fingerprint was recognizable was regarded as defective (×), and the case where the fingerprint could not be recognized was recorded as good (○), and the fingerprint resistance was evaluated. The evaluation results of the fingerprint resistance are shown in Table 1.

[Table 1]

As shown in Table 1, the adhesive sheets of Reference Examples 1 to 3 having the fingerprint-resistant layer were confirmed to be difficult to be marked. On the other hand, in the adhesive sheets of Comparative Examples 1 and 2 which did not have the fingerprint-resistant layer, it was confirmed that the fingerprint was easily noticeable. According to the results, it was found that the adhesive sheet of Example 1 having the fingerprint-resistant layer showed Ra, Wa, and fingerprint resistance similar to those of the adhesive sheets of Reference Examples 1 to 3.

(electromagnetic shielding effect)

With respect to each of the adhesive sheets obtained in Example 1 and Reference Example 2, the electric field shielding effect (db) and the magnetic field shielding effect (db) were measured by the KEC method (measurement frequency: 1 MHz to 1000 MHz (RFID: 13.56 MHz)). The results are shown in Table 2.

The present invention is not limited to the above-described embodiments, and various modifications can be made without departing from the scope of the invention. The embodiments obtained by appropriately combining the technical means disclosed in the different embodiments are also included in the technical scope of the present invention.

1‧‧‧Fingerprint resistant layer

2‧‧‧Colored layer

3‧‧‧Plastic layer

4‧‧‧metal layer

5‧‧‧Adhesive layer

10‧‧‧Substrate layer

30‧‧‧Adhesive tablets

Claims (10)

An adhesive sheet comprising: a base layer; a colored layer laminated on one main surface of the base layer; a fingerprint-resistant layer laminated on the colored layer; and a layer laminated on the opposite side of the base layer from the colored layer The adhesive layer on the main surface, wherein the base material layer comprises a plastic layer and a metal layer, and a surface of the surface of the anti-fingerprint treatment layer opposite to the colored layer has a Wa of 150 Å or more and Ra of 2000 Å or more. The adhesive sheet of claim 1, wherein the adhesive layer contains an acrylic polymer having a (meth)acrylic acid alkyl ester as a main component of the monomer. The adhesive sheet of claim 1 or 2, wherein the plastic layer is a polyethylene terephthalate layer. The adhesive sheet according to any one of claims 1 to 3, wherein the metal layer is an aluminum layer. The adhesive sheet according to any one of claims 1 to 4, wherein the substrate layer has a thickness of 2 to 150 μm. The adhesive sheet according to any one of claims 1 to 5, wherein the plastic layer has a thickness of from 1 to 100 μm. The adhesive sheet according to any one of claims 1 to 6, wherein the metal layer has a thickness of 1 to 50 μm. The adhesive sheet according to any one of claims 1 to 7, wherein the color of the colored layer is black. The adhesive sheet according to any one of claims 1 to 8, wherein the colored layer has a thickness of 0.3 to 5 μm. The adhesive sheet according to any one of claims 1 to 9, which is an adhesive sheet for an electronic device.