KR20150032464A - Pressure-sensitive adhesive sheet - Google Patents

Abstract

Provided is an adhesive sheet having adhesion not reduced in case of forming a primer layer and having excellent adhesive sheet. The adhesive sheet (10) of the present invention includes a base material (5) and an adhesive layer (3). The base material (5) is a laminated base material having a plastic base material (4), a primer layer (2), and a colored layer (1) sequentially laminated. The primer layer (2) includes a coloring agent. The content of the colored agent in the primer layer (2) is preferred to be 0.01-60 wt%. Moreover, the colored layer (1) and the coloring agent are preferred to be black.

Description

{PRESSURE-SENSITIVE ADHESIVE SHEET}

The present invention relates to a pressure-sensitive adhesive sheet.

BACKGROUND ART [0002] Conventionally, in a liquid crystal display device such as a cellular phone or a touch panel, an adhesive sheet having a light-shielding layer is used between a liquid crystal display module unit and a backlight unit relating to a display screen. The light-shielding layer prevents the backlight from leaking to the liquid crystal display module side, thereby improving the visibility.

As a pressure sensitive adhesive sheet having such a light shielding layer, there is known a constitution in which a pressure sensitive adhesive layer is formed on a laminated substrate in which a black printing layer is formed on a plastic substrate (see, for example, Patent Document 1).

Japanese Patent Application Laid-Open No. 2009-197124

In the laminated substrate used for the pressure sensitive adhesive sheet as described above, a primer layer is usually formed between the printed layer and the plastic substrate in order to improve the adhesion between the printed layer and the plastic substrate. However, since the surface of the primer layer is not smooth, variations in the thickness of the printed layer stacked thereover can occur. For this reason, light may leak in a thin portion of the print layer depending on the usage.

Therefore, an object of the present invention is to provide a pressure-sensitive adhesive sheet which is excellent in light shielding property without deteriorating the adhesive property even when a primer layer is formed.

In order to solve the above problems, a pressure-sensitive adhesive sheet according to the present invention comprises a base material and a pressure-sensitive adhesive layer, wherein the base material is a laminated base material in which a plastic substrate, a primer layer and a colored layer are laminated in this order, And the like.

In the pressure-sensitive adhesive sheet disclosed herein, the content of the coloring agent in the primer layer is preferably 0.01 to 60% by weight.

Further, in the pressure-sensitive adhesive sheet disclosed herein, it is preferable that the colored layer is black.

Further, in the pressure-sensitive adhesive sheet disclosed herein, it is preferable that the coloring agent is black.

Further, in the pressure-sensitive adhesive sheet disclosed herein, it is preferable that the pressure-sensitive adhesive layer is a pressure-sensitive adhesive layer formed of an acrylic pressure-sensitive adhesive.

INDUSTRIAL APPLICABILITY According to the present invention, it is possible to provide a pressure-sensitive adhesive sheet which is excellent in light shielding property without deteriorating the adhesive property even when a primer layer is formed.

1 is a cross-sectional view schematically showing a schematic configuration of a pressure-sensitive adhesive sheet according to the present embodiment.

Hereinafter, the present invention will be described in detail.

The pressure-sensitive adhesive sheet according to the present invention comprises a substrate and a pressure-sensitive adhesive layer.

In the present specification, " A to B " indicating the range means A to B or less. The various physical properties exemplified in this specification refer to values measured by the methods described in the following examples, unless otherwise specified. In the present specification, "(meth) acrylic" in "(meth) acrylic acid" refers to "acrylic and / or methacrylic". Further, in the present specification, the "adhesive sheet" includes a tape-like configuration, that is, an "adhesive tape".

In the present specification, the " main component " means the component having the highest content ratio based on the weight of the composition, and usually means 50 wt% or more.

(I)

The substrate is a laminated substrate obtained by laminating a plastic substrate, a primer layer and a colored layer in this order. The total thickness of the substrate may be, for example, 0.1 to 100 탆, preferably 1 to 50 탆, more preferably 5 to 20 탆.

(Plastic substrate)

The plastic substrate is not particularly limited. As the material or material of the plastic substrate, for example, there may be mentioned a polyester (polyethylene terephthalate (PET), polyethylene naphthalate, polybutylene terephthalate, polybutylene naphthalate and the like), polyolefin (polyethylene, polypropylene, Etc.), polyvinyl alcohol, polyvinylidene chloride, polyvinyl chloride, polyvinyl chloride-vinyl acetate copolymer, polyvinyl acetate, polyamide, polyimide, cellulose, fluorine resin, polyether, polystyrene- , Polycarbonate, polyethersulfone, and the like. Among them, polyester is preferable from the viewpoints of cost, strength and the like, and polyethylene terephthalate is particularly preferable. These materials may be used alone or in combination of two or more, and may have a single layer or a multilayer.

If necessary, known additives such as fillers, flame retardants, anti-aging agents, antistatic agents, softening agents, ultraviolet absorbers, antioxidants, plasticizers and surfactants may be contained in the above-described base material.

The thickness of the plastic substrate (total thickness in the case of a plurality of plastic substrate layers) is, for example, 1 to 50 占 퐉, preferably 1 to 30 占 퐉, and more preferably 2 to 20 占 퐉.

The method for forming the substrate is not particularly limited, and examples thereof include a method of molding the resin composition constituting the plastic substrate into a sheet form using a molding method such as extrusion molding, inflation molding and calender molding. From the viewpoint of the strength, it is preferable to effect orientation by stretching.

(Primer layer)

The primer layer includes a colorant. Examples of the primer layer include conventionally known structures and are not particularly limited. Examples of the primer layer include a urethane (polyisocyanate) resin, a polyester resin, an acrylic resin, a polyamide resin, a melamine resin, Polystyrene resins, epoxy resins, phenol resins, isocyanurate resins, polyvinyl acetate resins, and the like. Above all, a urethane resin or an acrylic resin having good compatibility with a plastic substrate (for example, a PET substrate) and a print layer are preferable from the viewpoint of improving adhesion. As materials for forming these primer layers, those having a glass transition point of 20 占 폚 or higher, more preferably 20 to 120 占 폚 are preferably used.

The resin used for the primer layer may have reactivity such as cross-linking curing, polymerization, condensation, and the like, and may react with the resin to express the physical properties. A crosslinking agent can be appropriately added to the crosslinking curing and the like. Further, a functional additive such as an antistatic agent may be added to the primer layer to impart other functions.

A suitable example of the material for forming the primer layer is an acrylic resin. As the acrylic resin, for example, a copolymer obtained by copolymerizing methyl methacrylate as a main component and a (meth) acrylic acid alkyl ester other than methyl methacrylate or a copolymerizable monomer is used.

Examples of the alkyl ester of the (meth) acrylic acid alkyl ester include a methyl ester, an ethyl ester, a propyl ester, an isopropyl ester, a butyl ester, an isobutyl ester, a s-butyl ester, And examples thereof include esters, hexyl esters, heptyl esters, octyl esters, 2-ethylhexyl esters, isooctyl esters, nonyl esters, decyl esters, isodecyl esters, undecyl esters, dodecyl esters, tridecyl esters, , Octadecyl ester and eicosyl ester, and the like, and straight chain or branched alkyl esters having 1 to 30 carbon atoms, particularly 4 to 18 carbon atoms.

Examples of the copolymerizable monomers include carboxyl group-containing monomers such as (meth) acrylic acid, carboxyethyl acrylate, carboxypentyl acrylate, itaconic acid, maleic acid, fumaric acid and crotonic acid; Acid anhydride monomers such as maleic anhydride and itaconic anhydride; (Meth) acrylate such as 2-hydroxyethyl (meth) acrylate, 2-hydroxypropyl (meth) acrylate, 4-hydroxybutyl (meth) acrylate, 6-hydroxyhexyl (Meth) acrylate such as 10-hydroxydecyl (meth) acrylate, 12-hydroxylauryl (meth) acrylate, [4- (hydroxymethyl) cyclohexyl] methyl acrylate, A silyl group-containing monomer; Sulfonic acid such as styrenesulfonic acid, allylsulfonic acid, 2- (meth) acrylamido-2-methylpropanesulfonic acid, (meth) acrylamidopropanesulfonic acid, sulfopropyl (meth) acrylate and (meth) acryloyloxynaphthalenesulfonic acid Group-containing monomers; Phosphoric acid group-containing monomers such as 2-hydroxyethyl acryloyl phosphate; Amino group-containing monomers such as dimethylaminoethyl methacrylate and t-butylaminoethyl methacrylate; Epoxy group-containing monomers such as (meth) acrylic acid glycidyl ester; Other examples include (meth) acrylamide, vinyl acetate, styrene, acrylonitrile and the like. The amount of the (meth) acrylic acid alkyl ester or the copolymerizable monomer copolymerized with the methyl methacrylate is preferably 50% by weight or less based on the total monomer components.

When the carboxyl group-containing monomer or the acid anhydride monomer is used as the copolymerizable monomer, the acrylic resin used as the material for forming the primer layer may be selected from butyl glycidyl ether, phenyl glycidyl ether, nonylphenyl glycidyl ether, etc. , Or amidated with a primary or secondary amine such as monomethylamine, dimethylamine, monoethylamine or diethylamine may be used. Furthermore, ethyleneimine or the like may be grafted to form a grafted product of polyethyleneimine.

The primer layer can be formed by a method in which a film containing the forming material of the above-mentioned primer layer is pressed on the plastic substrate, a method in which a melt of the forming material is coated and cooled, or a method in which a solution of the forming material is applied and dried . The coating method can be appropriately selected, but gravure coating, reverse roll coating, spray coating and the like are preferably used in order to adjust the thickness precision to 0.5 占 퐉 to 10 占 퐉.

As the colorant, conventionally known pigments or dyes can be used. Examples of the pigment include pigments such as zinc carbonate, zinc oxide, zinc sulfide, talc, carbon dioxide, calcium carbonate, titanium oxide, silica, lithium fluoride, calcium fluoride, barium sulfate, alumina, zirconia, iron oxide, iron hydroxide, Inorganic pigments such as chromium oxide, chromium oxide, chromium oxide, chromium oxide, chromium oxide, chromium oxide, chromium oxide, chromium oxide, chromium oxide, chromium oxide, chromium oxide, chromium oxide, chromium oxide, chromium oxide, chromium oxide, chromium oxide, Organic pigments such as perynone type, indigo · thioindigo type, isoindolinone type, azomethine type, dioxo type, quinacridone type, aniline black type, triphenylmethane type and carbon black type.

Examples of the dye include azo dyes, anthraquinone, quinonaphthalone, styryl, diphenylmethane, triphenylmethane, oxazine, triazine, xanthan, methane, azomethine, acridine, .

The content of the coloring agent in the primer layer is not particularly limited and may be, for example, from 0.01 to 60% by weight, preferably from 1 to 50% by weight, and more preferably from 10 to 40% by weight.

(Colored layer)

As the colored layer, for example, there may be mentioned layers exhibiting respective colors such as black, gray, white, red, blue, yellow, green, yellowish green, orange, purple, gold, silver, desirable.

The colored layer may be formed by an ink composition. The ink composition contains a coloring material (coloring agent) representing each color such as black as an essential component and, if necessary, comprises a binder, a dispersant, a solvent, and the like. The colored layer can be formed by applying the ink composition onto a support, drying and curing the composition as necessary.

The coloring material may be any coloring material (coloring agent) such as a pigment and a dye, but a pigment can be suitably used. Specifically, examples of the black-based coloring material include carbon black (such as a furnace black, a channel black, an acetylene black, a thermal black, a lamp black and a black matrix), graphite, copper oxide, manganese dioxide, aniline black, Titanium black, cyanine black, activated carbon, ferrite (nonmagnetic ferrite, magnetic ferrite and the like), magnetite, chromium oxide, iron oxide, molybdenum disulfide, chromium complex, complex oxide black pigment and anthraquinone type organic black pigment. Among them, carbon black is preferable from the viewpoints of cost and availability. The black coloring materials may be used alone or in combination of two or more.

As the coloring material showing black, a coloring material mixed with a plurality of coloring materials selected from a black coloring material, a cyan coloring material (cyan coloring material), a magenta coloring material (red coloring material) and a yellow coloring material (yellow coloring material) Mixtures may also be used.

The coloring layers other than black can be similarly formed.

Examples of the method for forming the colored layer include a known coating method and a method using various printing methods (gravure printing, flexographic printing, offset printing, relief printing, screen printing, etc.).

The total content of the coloring material in the ink composition is preferably 20 to 60% by weight, and more preferably 30 to 50% by weight, based on the solid content (nonvolatile component such as colorant and binder) of the ink composition. If the content of the coloring material is less than 20% by weight, the light-shielding property against the thickness is low, which makes it difficult to make the colored layer (for example, the light-blocking printing layer) thin. When the content exceeds 60% by weight, the fixability of the coloring material may be lowered.

The coloring layer may have any form of a single layer or multilayer, but preferably has a multilayer form. Therefore, it is preferable that the pressure-sensitive adhesive sheet (for example, double-sided pressure-sensitive adhesive tape) disclosed herein has a light-shielding print layer of a multilayer structure as a colored layer. By forming the light-shielding print layer in such a multilayer structure, the light shielding property can be further enhanced, and the pin hole reducing effect can also be obtained. The number of layers of the coloring layer (for example, the light-shielding printing layer) is not particularly limited as it may vary depending on the layer thickness and the degree of light shielding per layer, and is, for example, about 1 to 5, 2 to 5, more preferably 3 to 5 (especially 3 or 5).

The total thickness of the colored layer (the total thickness of the colored layer in the case of a multi-layered structure) is not particularly limited and is preferably 1 to 7 mu m, more preferably 1 to 6 mu m, Preferably 1 to 5 mu m.

(II) Pressure-sensitive adhesive layer

The pressure-sensitive adhesive for forming the pressure-sensitive adhesive layer is not particularly limited, and examples thereof include pressure sensitive adhesives such as a urethane pressure-sensitive adhesive, an acrylic pressure-sensitive adhesive, a rubber pressure-sensitive adhesive, a silicone pressure-sensitive adhesive, a polyester pressure-sensitive adhesive, a polyamide pressure-sensitive adhesive, And a known pressure-sensitive adhesive such as a pressure-sensitive adhesive. The pressure-sensitive adhesives may be used alone or in combination of two or more. The pressure-sensitive adhesive may be a pressure-sensitive adhesive having any form. The pressure-sensitive adhesive may be, for example, an emulsion type pressure-sensitive adhesive, a solvent type pressure-sensitive adhesive, a heat-melt type pressure-sensitive adhesive (hot melt type pressure-sensitive adhesive)

As the pressure-sensitive adhesive, an acrylic pressure-sensitive adhesive or a rubber pressure-sensitive adhesive can be suitably used. The acrylic pressure-sensitive adhesive contains an acrylic polymer as a base polymer (typically, it is included as a main component). The acrylic polymer is not particularly limited, but (meth) acrylic acid alkyl ester (acrylic acid alkyl ester, methacrylic acid alkyl ester) having a straight chain or branch chain alkyl group is preferably used as the main constituent monomer component (monomer main component). Specific examples of the (meth) acrylic acid alkyl ester include methyl (meth) acrylate, ethyl (meth) acrylate, propyl (meth) acrylate, isopropyl (meth) acrylate, butyl (Meth) acrylate, neopentyl (meth) acrylate, hexyl (meth) acrylate, heptyl (meth) acrylate, isobutyl (meth) acrylate, (Meth) acrylate, 2-ethylhexyl (meth) acrylate, octyl (meth) acrylate, isooctyl (meth) acrylate, nonyl ) Undecyl acrylate, and dodecyl (meth) acrylate. (Meth) acrylic acid alkyl ester may be used alone or in combination of two or more.

As the monomer component constituting the acrylic polymer, other monomer components (sometimes referred to as " copolymerizable monomer component ") capable of copolymerizing with the (meth) acrylic acid alkyl ester are used when the (meth) acrylic acid alkyl ester is a monomer main component . The (meth) acrylic acid alkyl ester is preferably used in a proportion of 50% by weight or more based on the total amount of the monomer components constituting the acrylic polymer.

The copolymerizable monomer component can be used for introducing a crosslinking point into the acrylic polymer or for increasing cohesion of the acrylic polymer. The copolymerizable monomer component may be used alone or in combination of two or more.

Concretely, as the copolymerizable monomer component, a functional group-containing monomer component (particularly a monomer component having a thermally crosslinkable functional group for introducing a crosslinking point for thermally crosslinking to an acrylic polymer) can be used for introducing a crosslinking point into the acrylic polymer have. Such a functional group-containing monomer component is not particularly limited as far as it is a monomer component capable of copolymerizing with a (meth) acrylic acid alkyl ester and having a functional group which is a crosslinking point. Examples thereof include carboxyl group-containing monomers such as (meth) acrylic acid, itaconic acid, crotonic acid, maleic acid, fumaric acid and isocrotonic acid, and acid anhydrides thereof (maleic anhydride, itaconic anhydride and the like); (Meth) acrylate such as 2-hydroxyethyl (meth) acrylate, 2-hydroxypropyl (meth) acrylate and 2-hydroxybutyl (meth) ; (Meth) acrylamide, N, N-dimethyl (meth) acrylamide, N-butyl (meth) acrylamide, Amide-based monomers such as methoxymethyl (meth) acrylamide and N-butoxymethyl (meth) acrylamide; Amino group-containing monomers such as aminoethyl (meth) acrylate, N, N-dimethylaminoethyl (meth) acrylate, and t-butylaminoethyl (meth) acrylate; Epoxy group-containing monomers such as glycidyl (meth) acrylate and methylglycidyl (meth) acrylate; Cyano-containing monomers such as acrylonitrile and methacrylonitrile; Vinyl pyrrolidone, N-vinylpyrrolidone, N-vinylpyridine, N-vinylpiperidone, N-vinylpyrimidine, N-vinylpiperazine, N-vinylpyrazine, N- , Monomers having nitrogen atom-containing rings such as N-vinylimidazole, N-vinyloxazole, N-vinylmorpholine, N-vinylcaprolactam and N- (meth) acryloylmorpholine; And the like. As the functional group-containing monomer component, a carboxyl group-containing monomer such as acrylic acid or an acid anhydride thereof can be suitably used.

As the copolymerizable monomer component, other copolymerizable monomer components may be used in order to increase cohesion of the acrylic polymer. Examples of the other copolymerizable monomer component include vinyl ester monomers such as vinyl acetate and vinyl propionate; Styrene monomers such as styrene, substituted styrene (? -Methylstyrene and the like) and vinyltoluene; (Meth) acrylic acid cycloalkyl ester [(meth) acrylate cyclohexyl, cyclopentyl (meth) acrylate, etc.], nonaromatic ring containing compounds such as boron (meth) acrylate and isobornyl ) Acrylic acid esters; (Meth) acrylic acid aryl esters such as [(meth) acrylate], (meth) acrylate aryloxyalkyl esters such as phenoxy ethyl acrylate and the like, (meth) acrylic acid arylalkyl esters [(meth) (Meth) acrylic acid esters including aromatic ring-containing (meth) acrylic acid esters; Olefinic monomers such as ethylene, propylene, isoprene, butadiene and isobutylene; Vinyl chloride, vinylidene chloride; Isocyanate group-containing monomers such as 2- (meth) acryloyloxyethyl isocyanate; Alkoxy group-containing monomers such as methoxyethyl (meth) acrylate and ethoxyethyl (meth) acrylate; Vinyl ether monomers such as methyl vinyl ether and ethyl vinyl ether; Acrylate, diethylene glycol di (meth) acrylate, triethylene glycol di (meth) acrylate, tetraethylene glycol di (meth) acrylate, (Meth) acrylate, propylene glycol di (meth) acrylate, (poly) propylene glycol di (meth) acrylate, neopentyl glycol di (meth) acrylate, pentaerythritol di (Meth) acrylate, trimethylolpropane tri (meth) acrylate, pentaerythritol tri (meth) acrylate, dipentaerythritol hexa (meth) acrylate, glycerin di Polyfunctional monomers such as acrylate, urethane acrylate, divinylbenzene, butyl di (meth) acrylate and hexyl di (meth) acrylate; And the like.

Examples of the rubber adhesives include natural rubber, styrene-isoprene-styrene block copolymer (SIS block copolymer), styrene-butadiene-styrene block copolymer (SBS block copolymer), styrene-ethylene-butylene-styrene block copolymer A rubber component such as styrene-butadiene rubber, polybutadiene, polyisoprene, polyisobutylene, butyl rubber, chloroprene rubber, silicone rubber, acrylonitrile-butadiene rubber and ethylene-propylene terpolymer And a rubber-based pressure-sensitive adhesive.

If necessary, known additives such as a crosslinking agent, a cross-linking agent, a tackifier resin, a filler, a flame retardant, an antioxidant, an antistatic agent, a softening agent, an ultraviolet absorber, an antioxidant, a plasticizer and a surfactant are included in the pressure- .

The pressure-sensitive adhesive layer may have any one of a single layer and a multilayer.

The thickness of the pressure-sensitive adhesive layer (one-side pressure-sensitive adhesive sheet side) is not particularly limited and is preferably 1 to 200 占 퐉, for example, from the viewpoint of thinning of the pressure-sensitive adhesive sheet (double-sided pressure-sensitive adhesive tape, for example) Is 3 to 100 mu m.

The method of forming the pressure-sensitive adhesive layer is not particularly limited, and examples thereof include a method of applying a pressure-sensitive adhesive on a predetermined surface and drying and curing the pressure-sensitive adhesive layer as necessary, a method of applying an adhesive on a separator (release liner) Curing the pressure-sensitive adhesive layer to form a pressure-sensitive adhesive layer, and then the pressure-sensitive adhesive layer is bonded on a predetermined surface and transferred. For application of the pressure-sensitive adhesive, it is possible to use a conventional coating machine (for example, a gravure roll coater, a reverse roll coater, a kiss roll coater, a dip roll coater, a bar coater, a knife coater and a spray coater).

In a preferred embodiment, the pressure-sensitive adhesive layer comprises an acrylic pressure-sensitive adhesive containing 50 to 99% by weight of a (meth) acrylic acid alkyl ester and 80 to 100% by weight of an acrylic polymer containing 1 to 10% by weight of a carboxyl group- A). In a more preferred embodiment, the acrylic pressure-sensitive adhesive (A) contains 0.01 to 5 parts by weight of a crosslinking agent such as an isocyanate crosslinking agent or an epoxy crosslinking agent based on 100 parts by weight of the acrylic polymer.

(III) Pressure-sensitive adhesive sheet

Brief Description of the Drawings Fig. 1 is a cross-sectional view schematically showing a schematic configuration of an example of a pressure-sensitive adhesive sheet according to the present embodiment. 1, the pressure-sensitive adhesive sheet 10 according to the present embodiment includes a substrate 5 and a pressure-sensitive adhesive layer 3, and the substrate 5 includes a plastic substrate 4, a primer layer 2, And a colored layer 1 are laminated in this order.

In the embodiment shown in Fig. 1, the pressure-sensitive adhesive layer 3 is provided on both sides of the base material 5, but the pressure-sensitive adhesive layer 3 may be provided only on one side of the base material 5. [ Further, another layer such as a primer layer may be provided between the substrate 5 and the pressure-sensitive adhesive layer 3. [

<Examples>

Hereinafter, the present invention will be described in more detail with reference to examples and comparative examples. However, the present invention is not limited to the following examples and comparative examples at all. In the following description, &quot; part &quot; and &quot;% &quot; are by weight unless otherwise specified.

[Example 1]

(Acrylic adhesive)

70 parts by weight of n-butyl acrylate, 27 parts by weight of 2-ethylhexyl acrylate, 3 parts by weight of acrylic acid, 0.2 part by weight of azobisisobutyronitrile and 0.2 part by weight of acrylic acid were added to a reactor equipped with a thermometer, a stirrer, 235 parts by weight of ethyl acetate as a solvent was added and stirred for 1 hour while introducing nitrogen gas. After the oxygen in the polymerization system was removed in this way, the temperature was raised to 63 캜 and the reaction was carried out for 10 hours. Thereafter, the solution was cooled to room temperature to obtain an acrylic polymer solution having a solid concentration of 30% by weight. To 100 parts by weight (in terms of solid content) of this acrylic polymer solution, 0.05 part by weight of a tetrafunctional epoxy cross-linking agent ("TERTRAD C" manufactured by Mitsubishi Gas Chemical Company) was added to prepare a transparent acrylic pressure-sensitive adhesive.

(Double-sided adhesive tape)

(A black ink ("NB-300 Ink" manufactured by Dainichiseika Kogyo Co., Ltd.)) and a urethane-based primer composition ("NB-300 Ink" manufactured by Dainichiseika Kogyo K.K.) were laminated on one side of a transparent polyethylene terephthalate (PET) Resin in a mixing ratio of 30:70] was applied by a gravure printing method to form a primer layer.

Black ink ("NB-300 Ink" manufactured by Dainichiseika Kogyo Co., Ltd.) was applied onto the primer layer five times by gravure printing to form a black print layer (five layers) having a total thickness of 5 μm as a colored layer To obtain a laminate (thickness: 10 μm) having a laminated structure of a transparent PET substrate / primer layer / black print layer (5 layers).

The acrylic pressure-sensitive adhesive was applied to both surfaces of the laminate so that the pressure-sensitive adhesive layer had a thickness of 10 mu m to obtain a double-sided pressure-sensitive adhesive tape having a thickness of 30 mu m.

[Comparative Example 1]

A double-faced pressure-sensitive adhesive tape was obtained in the same manner as in Example 1 except that no pigment was added to the primer.

(Light leakage evaluation)

The double-sided pressure-sensitive adhesive tape obtained in Example 1 and Comparative Example 1 was evaluated as follows.

Evaluation method: Set the LED lamp (20W) in the dark room to the bottom of a 20cm high (75mm diameter) and place the obtained double-sided adhesive tape on the top of the barrel. Visually check whether light leakage occurs from the double-sided adhesive tape when the LED lamp is irradiated.

As a result, in the tape obtained in Comparative Example 1, light leakage of not less than 0.5 mm in diameter was visually confirmed, but in the tape obtained in Example 1, there was no light leakage which can be judged by the naked eye.

It is to be understood that the present invention is not limited to the above-described embodiments, and that various changes can be made within the scope of the claims, and embodiments obtained by appropriately combining the technical means disclosed in the other embodiments are included in the technical scope of the present invention do.

1: colored layer
2: Primer layer
3: Pressure-sensitive adhesive layer
4: plastic substrate
5: substrate
10: Pressure sensitive adhesive sheet

Claims (5)

And a pressure-sensitive adhesive layer,
The substrate is a laminated substrate obtained by laminating a plastic substrate, a primer layer and a colored layer in this order,
Wherein the primer layer comprises a colorant. The pressure-sensitive adhesive sheet according to claim 1, wherein the content of the coloring agent in the primer layer is 0.01 to 60% by weight. The adhesive sheet according to claim 1 or 2, wherein the colored layer is black. The adhesive sheet according to any one of claims 1 to 3, wherein the coloring agent is black. The pressure-sensitive adhesive sheet according to any one of claims 1 to 4, wherein the pressure-sensitive adhesive layer is a pressure-sensitive adhesive layer formed of an acrylic pressure-sensitive adhesive.

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