adhesive sheet

Abstract

Provided is an adhesive sheet including, in the given order, a substrate, a metal-evaporated layer, and a rubber hot-melt adhesive agent layer. The adhesive sheet further includes a coating layer that contains a polyester resin and that is disposed between the metal-evaporated layer and the rubber hot-melt adhesive agent layer.

Description

[Technical Field]

[0001] The present invention relates to a pressure-sensitive adhesive sheet. [Background technology]

[0002] Conventionally, pressure-sensitive adhesives have been widely used in pressure-sensitive adhesive sheets due to their excellent properties such as flexibility, elasticity, and adhesiveness. The most common method for producing pressure-sensitive adhesives is the solvent method, in which rubber or the like is dissolved in a solvent, the solution is applied to a substrate, and then the substrate is heated to dry the solvent. However, this solvent method has drawbacks, such as the long time required to dissolve rubber or the like in the solvent.

[0003] Therefore, in recent years, hot-melt pressure-sensitive adhesives that can be applied to a substrate by heating and melting have been suitably used (see, for example, Patent Documents 1 and 2). [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Application Laid-Open No. 2017-179240 [Patent Document 2] Japanese Patent Application Publication No. 7-278509 Summary of the Invention [Problem to be solved by the invention]

[0005] A hot-melt pressure-sensitive adhesive layer that can be applied to a substrate by heat melting may be formed on the substrate via a metal vapor deposition layer. That is, a metal vapor deposition layer may be disposed between the substrate and the hot-melt pressure-sensitive adhesive layer. The surface of the metal vapor deposition layer is highly smooth, making it difficult to obtain adhesion with the hot-melt pressure-sensitive adhesive layer, and there are often problems with interlayer adhesion between the substrate and the hot-melt pressure-sensitive adhesive layer. In particular, pressure-sensitive adhesive sheets in which a hot-melt pressure-sensitive adhesive layer is formed using a rubber-based pressure-sensitive adhesive have a problem in that the pressure-sensitive adhesive may remain on the adherend, i.e., adhesive residue may occur, when the sheet is peeled from the adherend.

[0006] The present invention has been made to solve the above-mentioned problems, and aims to provide a pressure-sensitive adhesive sheet having a metal vapor deposition layer and a rubber-based hot-melt pressure-sensitive adhesive layer, which suppresses the occurrence of adhesive residue when peeled off. [Means for solving the problem]

[0007] The present inventors have found that the above problems can be solved by disposing a coating layer containing a polyester resin between the metal vapor deposition layer and the rubber-based hot-melt pressure-sensitive adhesive layer, and have completed the present invention. That is, the present invention provides the following [1] to [7]. [1] A pressure-sensitive adhesive sheet having a substrate, a metal vapor deposition layer, and a rubber-based hot-melt pressure-sensitive adhesive layer in this order, The pressure-sensitive adhesive sheet further comprises a coating layer containing a polyester resin, the coating layer being disposed between the metal vapor deposition layer and the rubber-based hot-melt pressure-sensitive adhesive layer. [2] The pressure-sensitive adhesive sheet according to the above [1], wherein the coating layer further contains at least one of a polyurethane resin and a polyolefin resin. [3] The pressure-sensitive adhesive sheet according to the above [1] or [2], wherein the metal vapor deposition layer is an aluminum vapor deposition layer. [4] The pressure-sensitive adhesive sheet according to any one of the above [1] to [3], wherein the substrate is a resin film containing a polyester-based resin. [5] The pressure-sensitive adhesive sheet according to any one of the above [1] to [4], wherein the polyester resin contained in the coating layer has a glass transition temperature of 20 to 80°C. [6] The pressure-sensitive adhesive sheet according to any one of the above [1] to [5], further comprising a release liner on the rubber-based hot-melt pressure-sensitive adhesive layer on the side opposite to the coating layer. [7] A method for producing a pressure-sensitive adhesive sheet having, in this order, a substrate, a metal vapor deposition layer, a coating layer containing a polyester resin, and a rubber-based hot-melt pressure-sensitive adhesive layer, comprising: A method for producing a pressure-sensitive adhesive sheet, comprising a step of applying a coating liquid having a pH of 5 or more and a pH of 9 or less to form a coating layer. [Effects of the Invention]

[0008] According to the present invention, it is possible to provide a pressure-sensitive adhesive sheet having a metal vapor deposition layer and a rubber-based hot-melt pressure-sensitive adhesive layer, which is suppressed from leaving adhesive residue when peeled off. [Brief explanation of the drawings]

[0009] [Figure 1] 1 is a cross-sectional view showing the configuration of a pressure-sensitive adhesive sheet according to a first embodiment of the present invention. [Figure 2] FIG. 3 is a cross-sectional view showing the configuration of a pressure-sensitive adhesive sheet according to a second embodiment of the present invention. DETAILED DESCRIPTION OF THE INVENTION

[0010] In this specification, the "weight average molecular weight" is based on polystyrene equivalent determined by gel permeation chromatography (GPC). Furthermore, for preferred numerical ranges (e.g., ranges of content, etc.), the lower and upper limits described in stages can be independently combined. For example, the description "preferably 10 to 90, more preferably 30 to 60" can be combined with the "preferable lower limit (10)" and the "more preferable upper limit (60)" to form "10 to 60." In this specification, the term "adhesive residue" refers to adhesive remaining on an adherend when a pressure-sensitive adhesive sheet is peeled off from the adherend.

[0011] [Adhesive sheet composition] The pressure-sensitive adhesive sheet of the present invention comprises, in this order, a substrate, a metal vapor-deposited layer, and a rubber-based hot-melt pressure-sensitive adhesive layer (hereinafter simply referred to as a "hot-melt pressure-sensitive adhesive layer"). The pressure-sensitive adhesive sheet of the present invention further comprises a coating layer containing a polyester resin, disposed between the metal vapor-deposited layer and the rubber-based hot-melt pressure-sensitive adhesive layer. The structure of the adhesive tape is not particularly limited as long as it has a coating layer containing a polyester resin between the metal vapor deposition layer and the hot melt adhesive layer. The coating layer is provided for the purpose of preventing adhesive residue from being left on the adherend during peeling. The adhesive sheet of the present invention may have other layers between the substrate and the metal vapor deposition layer, but from the viewpoint of further suppressing the occurrence of adhesive residue when peeled off, it is preferable that the adhesive sheet has a directly laminated structure having the substrate, metal vapor deposition layer, coating layer, and hot melt adhesive layer in this order without any other layers in between. In the pressure-sensitive adhesive sheet of the present invention, a release liner or the like may be provided on the hot-melt pressure-sensitive adhesive layer on the side opposite the coating layer, and a printed coating layer or the like may be provided on the substrate on the side opposite the coating layer. The pressure-sensitive adhesive sheet of the present invention may also be provided with other layers that do not fall under the category of the above-mentioned substrate, metal vapor deposition layer, coating layer, hot-melt pressure-sensitive adhesive layer, release liner, and printed coating layer.

[0012] FIG. 1 is a cross-sectional view showing the configuration of a pressure-sensitive adhesive sheet according to a first embodiment of the present invention. In the adhesive sheet 1a according to the first embodiment of the present invention, a metal vapor deposition layer 12 is provided on one side of a substrate 11, a coating layer 13 is provided on the metal vapor deposition layer 12, and a hot melt adhesive layer 14 is further provided on the coating layer 13.

[0013] FIG. 2 is a cross-sectional view showing the configuration of a pressure-sensitive adhesive sheet according to a second embodiment of the present invention. In the adhesive sheet 1b according to the first embodiment of the present invention, a metal vapor deposition layer 12 is provided on one side of a substrate 11, a coating layer 13 is provided on the metal vapor deposition layer 12, a hot melt adhesive layer 14 is provided on the coating layer 13, and a release liner 15 is provided on the hot melt adhesive layer 14. Each layer constituting the pressure-sensitive adhesive sheet of the present invention will be described below.

[0014] <Coating layer> The coating layer contains a polyester-based resin. By including a polyester-based resin in the coating layer, it is possible to provide a pressure-sensitive adhesive sheet having a metal vapor deposition layer and a rubber-based hot-melt pressure-sensitive adhesive layer, in which the occurrence of adhesive residue during peeling is suppressed. The reason for this effect is not clear, but is thought to be as follows. The polyester resin has a polar group such as an ester group. It is believed that the presence of such a polar group improves the adhesion between the metal vapor deposition layer and the coating layer containing the polyester resin. Meanwhile, the polyester resin is a hydrophobic resin that also contains hydrophobic groups. Therefore, it is believed that sufficient adhesion is ensured between the hot-melt pressure-sensitive adhesive layer containing a rubber component and the coating layer containing the polyester resin. In other words, since sufficient adhesion is ensured between the metal vapor deposition layer and the coating layer, and between the coating layer and the pressure-sensitive adhesive layer, it is believed that the hot-melt pressure-sensitive adhesive layer is prevented from remaining on the adherend (the occurrence of adhesive residue) when the pressure-sensitive adhesive sheet is peeled off.

[0015] In order to further suppress the occurrence of adhesive residue, particularly when peeled off at a high speed of about 30 m / min, the coating layer preferably further contains at least one of a polyurethane resin and a polyolefin resin in addition to the polyester resin. Furthermore, the coating layer may contain other resins other than the polyester resin, polyurethane resin, and polyolefin resin, a crosslinking agent, other additives, etc., as necessary.

[0016] The thickness of the coating layer is not particularly limited, but from the viewpoint of interlayer adhesion between the coating layer and the hot-melt pressure-sensitive adhesive layer, it is preferably 0.01 μm or more, more preferably 0.2 μm or more, particularly preferably 0.3 μm or more, and preferably 10 μm or less, more preferably 5 μm or less, particularly preferably 2 μm or less. The thickness of the coating layer is specifically a value measured and calculated based on the method described in the examples below.

[0017] The method for forming the coating layer is not particularly limited, but from the viewpoint of environmental impact and coating safety, such as preventing ignition accidents due to static electricity, it is preferable to include a step of applying an aqueous coating liquid containing a polyester-based resin to a substrate. The polyester-based resin in the aqueous coating liquid may be in a form dispersed or dissolved in water, but is preferably in a dispersed form. That is, the coating layer is preferably a layer formed by applying an aqueous resin dispersion in which a polyester-based resin is dispersed in water to a substrate. Furthermore, even when the coating layer further contains at least one of a polyurethane-based resin and a polyolefin-based resin, it is preferable to include a step of applying an aqueous coating liquid containing a polyester-based resin and at least one of a polyurethane-based resin and a polyolefin-based resin to a substrate. The polyester-based resin, polyurethane-based resin, and polyolefin-based resin in the aqueous coating liquid may be in a form dispersed or dissolved in water, but is preferably in a dispersed form. That is, the coating layer is preferably a layer formed by applying an aqueous resin dispersion, in which a polyester resin and at least one of a polyurethane resin and a polyolefin resin is dispersed in water, to the substrate. The aqueous resin dispersion refers to a dispersion containing water as a main component, with the water content being 50% by mass or more. The water-based coating liquid may contain a solvent as described in the "Method for producing a pressure-sensitive adhesive sheet" below, but it is preferable that it does not contain such a solvent.

[0018] [Polyester Resin] The polyester resin contained in the coating layer is not particularly limited, but is usually a resin having an ester bond in the main chain. From the viewpoint of suppressing adhesive residue, the polyester resin contained in the coating layer is preferably at least one of a polyester resin and a modified polyester resin, and more preferably a polyester resin.

[0019] There are no particular restrictions on the glass transition temperature of the polyester resin, but from the viewpoint of suppressing the occurrence of adhesive residue, it is preferably 20° C. or higher, more preferably 25° C. or higher, even more preferably 30° C. or higher, and particularly preferably 35° C. or higher, and from the viewpoint of coating film formability, it is preferably 80° C. or lower, more preferably 75° C. or lower, even more preferably 70° C. or lower, and particularly preferably 65° C. or lower. A glass transition temperature of 20° C. or higher is excellent in suppressing the occurrence of adhesive residue, and a glass transition temperature of 80° C. or lower makes it difficult for defects to occur and makes it easy to form a coating film. The glass transition temperature of the polyester resin is a value measured and calculated based on the method described in the examples below.

[0020] The hydroxyl value of the polyester resin is not particularly limited, but is preferably 0.5 KOHmg / g or more, more preferably 1 KOHmg / g or more, particularly preferably 2 KOHmg / g or more, and is preferably 10 KOHmg / g or less, more preferably 9 KOHmg / g or less, particularly preferably 8 KOHmg / g or less. The hydroxyl value of the polyester resin is a value measured and calculated based on the method described in the examples below.

[0021] The acid value of the polyester resin is not particularly limited, but is preferably 20 KOHmg / g or more, more preferably 30 KOHmg / g or more, particularly preferably 40 KOHmg / g or more, and is preferably 80 KOHmg / g or less, more preferably 70 KOHmg / g or less, particularly preferably 60 KOHmg / g or less. The acid value of the polyester resin is a value measured and calculated based on the method described in the examples below.

[0022] The number average molecular weight Mn of the polyester resin is not particularly limited, but is preferably 1,000 or more, more preferably 2,000 or more, and is preferably 10,000 or less, more preferably 5,000 or less.

[0023] The content of the polyester resin in the coating layer is not particularly limited, but when it does not contain the polyurethane resin and polyolefin resin described below, it is preferably 80% by mass or more, more preferably 90% by mass or more, even more preferably 95% by mass or more, and particularly preferably substantially 100% by mass. Furthermore, when it further contains at least one of the polyurethane resin and polyolefin resin described below in addition to the polyester resin, the content of the polyester resin in the coating layer is preferably 40% by mass or more, more preferably 45% by mass or more, even more preferably 48% by mass or more, and particularly preferably substantially 50% by mass.

[0024] (polyester resin) The polyester resin is a copolymer obtained by a polycondensation reaction between an acid component and a diol component or a polyol component. The polycondensation reaction is carried out by a general polyesterification reaction such as a direct esterification method or an ester exchange method. These polyester resins may be used alone or in combination of two or more.

[0025] Examples of the acid component include aromatic dicarboxylic acids such as terephthalic acid, phthalic acid, sulfoterephthalic acid, isophthalic acid, phthalic anhydride, α-naphthalenedicarboxylic acid, 2,6-naphthalenedicarboxylic acid, 5-sodium sulfoisophthalic acid, 5-potassium sulfoisophthalic acid, and anhydrides or esters thereof; aliphatic dicarboxylic acids such as pimelic acid, suberic acid, azelaic acid, oxalic acid, sebacic acid, succinic acid, adipic acid, undecylenic acid, dodecanedicarboxylic acid, and anhydrides or esters thereof; and alicyclic dicarboxylic acids such as 1,3-cyclohexanedicarboxylic acid, 1,3-cyclopentanedicarboxylic acid, 1,2-cyclohexanedicarboxylic acid, 1,2-cyclopentanedicarboxylic acid, 1,4-cyclohexanedicarboxylic acid, and anhydrides or esters thereof. These may be used alone or in combination of two or more.

[0026] Examples of the diol component or polyol component include aliphatic glycols such as ethylene glycol, 1,2-propylene glycol, 1,3-propylene glycol, 1,3-butanediol, 1,4-butanediol, 1,5-pentanediol, 1,6-hexanediol, 1,8-octanediol, 1,9-nonanediol, neopentyl glycol, 3-methylpentanediol, 2,2,3-trimethylpentanediol, diethylene glycol, triethylene glycol, and dipropylene glycol; alicyclic glycols such as 1,2-cyclohexanediol, 1,2-cyclohexanedimethanol, 1,4-cyclohexanediol, and 1,4-cyclohexanedimethanol; and aromatic glycols such as p-xylene glycol and bisphenol A. These may be used alone or in combination of two or more.

[0027] The polyester resin may have a reactive functional group. Specific examples of the reactive functional group include a hydroxyl group, a carboxyl group, and an amino group. The reactive functional group may be involved in a polymerization reaction (i.e., involved in main chain formation) or may be additionally provided. In polyester resins, a structural unit based on a polyol may have a hydroxyl group, or a structural unit based on a carboxylic acid component may have a carboxylic acid, and these residual hydroxyl groups or residual carboxylic acids may serve as the reactive functional group.

[0028] The polyester resin may have an active energy ray-polymerizable functional group. A polyester resin having such a structure can be produced, for example, by adding a compound having an active energy ray-polymerizable functional group to a monomer and / or oligomer (hereinafter also referred to as "monomer, etc.") during the polymerization reaction to form a polyester resin, and then reacting this compound with the monomer, etc., simultaneously with the polymerization reaction of the monomer, etc., to incorporate this compound into the backbone of the polyester resin. In this specification, "active energy rays" refers to electromagnetic waves or charged particle beams that have an energy quantum, i.e., active light such as ultraviolet light or electron beams.

[0029] (modified polyester resin) The modified polyester resin is not particularly limited as long as it is a modified polyester resin, and examples thereof include urethane-modified polyester resin, acrylic-modified polyester resin, silicone-modified polyester resin, etc. These may be used alone or in combination of two or more.

[0030] The urethane-modified polyester resin includes a polyester resin further having a urethane bond, and can be obtained, for example, by reacting a polyester resin having two or more functional groups such as hydroxyl groups in one molecule with a polyisocyanate compound. Specific examples of urethane-modified polyester resins include polymers (polyester urethanes) obtained by reacting various polyisocyanate compounds with polyester polyols having hydroxyl groups at the terminals of copolymers obtained by polycondensation reaction of the above-mentioned acid component with a diol component or a polyol component.

[0031] The polyisocyanate compound used for urethane modification of polyester resin is preferably a polyisocyanate compound having two or more isocyanate groups per molecule. Examples of polyisocyanate compounds having two or more isocyanate groups per molecule include diisocyanate compounds, triisocyanate compounds, tetraisocyanate compounds, pentaisocyanate compounds, hexaisocyanate compounds, etc. More specific examples include aromatic polyisocyanate compounds such as tolylene diisocyanate, diphenylmethane diisocyanate, and xylylene diisocyanate; alicyclic isocyanate compounds such as dicyclohexylmethane-4,4-diisocyanate, bicycloheptane triisocyanate, cyclopentylene diisocyanate, cyclohexylene diisocyanate, methylcyclohexylene diisocyanate, and hydrogenated xylylene diisocyanate; and aliphatic isocyanate compounds such as pentamethylene diisocyanate, hexamethylene diisocyanate, heptamethylene diisocyanate, trimethylhexamethylene diisocyanate, and lysine diisocyanate. These may be used alone or in combination of two or more. Modified products such as biurets and isocyanurates of these isocyanate compounds, and adducts which are reaction products of these isocyanate compounds with non-aromatic low-molecular-weight active hydrogen-containing compounds such as ethylene glycol, trimethylolpropane, and castor oil can also be used.

[0032] The urethane-modified polyester resin is preferably a urethane-modified polyester resin having a basic structure of an aromatic polyester, which has a repeating unit derived from an aromatic compound in the polyester structure of the main chain, for example, obtained when one or both of a dicarboxylic acid and a glycol compound in part or all of the copolymerization raw materials are aromatic compounds.

[0033] [Polyurethane resin] The coating layer preferably contains a polyurethane resin from the viewpoint of further suppressing the occurrence of adhesive residue. When the coating layer contains a polyurethane-based resin, the polarity of the coating layer decreases and the adhesion between the coating layer and the pressure-sensitive adhesive layer improves, making it possible to further suppress the occurrence of adhesive residue, particularly during high-speed peeling. The polyurethane resin is not particularly limited, but is usually a resin obtained by reacting a polyisocyanate component with a polyol component, and optionally chain-extending the resin in the presence of a chain extender, which is a low-molecular-weight compound having two or more active hydrogen atoms, such as a diol or diamine.

[0034] The glass transition temperature of the polyurethane resin is not particularly limited, but from the viewpoint of suppressing the occurrence of adhesive residue, it is preferably 40°C or higher, more preferably 60°C or higher, even more preferably 70°C or higher, and particularly preferably 80°C or higher, and from the viewpoint of coating film formability, it is preferably 130°C or lower, more preferably 110°C or lower, even more preferably 100°C or lower, and particularly preferably 90°C or lower. A glass transition temperature of 40°C or higher is excellent in suppressing the occurrence of adhesive residue, and a glass transition temperature of 130°C or lower makes it difficult for defects to occur and facilitates coating film formation. The glass transition temperature of the polyurethane resin is a value measured and calculated based on the method described in the examples below.

[0035] The acid value of the polyurethane resin is not particularly limited, but is preferably 1 KOHmg / g or more, more preferably 5 KOHmg / g or more, and particularly preferably 8 KOHmg / g or more, and is preferably 50 KOHmg / g or less, more preferably 40 KOHmg / g or less, and particularly preferably 30 KOHmg / g or less. The acid value of the polyurethane resin is a value measured and calculated based on the method described in the examples below.

[0036] The number average molecular weight Mn of the polyurethane resin is not particularly limited, but is preferably 1,000 or more, more preferably 2,000 or more, and is preferably 1,000,000 or less, more preferably 500,000 or less.

[0037] The content of the polyurethane resin in the coating layer is not particularly limited, but is preferably 40% by mass or more, more preferably 45% by mass or more, even more preferably 48% by mass or more, and particularly preferably 50% by mass.

[0038] The polyisocyanate component is not particularly limited, but from the viewpoint of suppressing the occurrence of adhesive residue, an aliphatic polyisocyanate is preferred. Examples of the aliphatic polyisocyanate include chain aliphatic polyisocyanates and cyclic aliphatic polyisocyanates.

[0039] Examples of the chain aliphatic polyisocyanate include trimethylene diisocyanate, 1,2-propylene diisocyanate, butylene diisocyanate (tetramethylene diisocyanate, 1,2-butylene diisocyanate, 2,3-butylene diisocyanate, 1,3-butylene diisocyanate), 1,5-pentamethylene diisocyanate (PDI), 1,6-hexamethylene diisocyanate (HDI), 2,4,4- or 2,2,4-trimethylhexamethylene diisocyanate, 2,6-diisocyanate methylcaprate, etc. Among these, HDI is preferred.

[0040] Examples of cyclic aliphatic polyisocyanates include 1,3-cyclopentane diisocyanate, 1,3-cyclopentene diisocyanate, cyclohexane diisocyanate (1,4-cyclohexane diisocyanate, 1,3-cyclohexane diisocyanate), 3-isocyanatomethyl-3,5,5-trimethylcyclohexyl isocyanate (IPDI), methylene bis(cyclohexyl isocyanate) (4,4'-, 2,4'-, or 2,2'-methylene bis(cyclohexyl isocyanate) their trans,trans-isomer, trans,cis-isomer, cis,cis-isomer, or mixtures thereof) (H 12 Examples include MDI), methylcyclohexane diisocyanate (methyl-2,4-cyclohexane diisocyanate, methyl-2,6-cyclohexane diisocyanate), norbornane diisocyanate (various isomers or mixtures thereof) (NBDI), 1,3- and 1,4-bis(isocyanatomethyl)cyclohexane (H6XDI) (also known as hydrogenated xylylene diisocyanate), etc. Among these, IPDI is particularly preferred.

[0041] Examples of the polyol component include polyether polyol, polyester polyol, and polycarbonate polyol.

[0042] Examples of polyether polyols include those obtained by ring-opening homopolymerization or ring-opening copolymerization of alkylene oxides (e.g., alkylene oxides having 2 to 5 carbon atoms, such as ethylene oxide, propylene oxide, butylene oxide, tetrahydrofuran, 3-methyltetrahydrofuran, and oxetane compounds) using a low-molecular-weight polyol as an initiator. Specific examples include polyoxyethylene glycol, polyoxypropylene glycol, polyoxyethylene-propylene copolymer, and polyoxytetramethylene glycol (polytetramethylene ether glycol).

[0043] The low molecular weight polyol is, for example, a low molecular weight polyol having two or more hydroxyl groups and a molecular weight of 60 to 400, such as ethylene glycol, propanediol, 1,4-butylene glycol (1,4-butanediol), 1,6-hexanediol, 1,2-butylene glycol, 1,3-butylene glycol, 1,5-pentanediol, 3-methyl-1,5-pentanediol, neopentyl glycol, alkane (having 7 to 22 carbon atoms) diol, diethylene glycol, triethylene glycol, dipropylene glycol, cyclohexanedimethanol, alkane-1,2-diol (having 17 to 20 carbon atoms), 1,4-dihydroxy-2-butene, 2,6-dimethyl- Examples of suitable low molecular weight diols include methyl-1-octene-3,8-diol, bishydroxyethoxybenzene, xylene glycol, and bishydroxyethylene terephthalate; low molecular weight triols such as glycerin, 2-methyl-2-hydroxymethyl-1,3-propanediol, 2,4-dihydroxy-3-hydroxymethylpentane, 1,2,6-hexanetriol, trimethylolpropane, 2,2-bis(hydroxymethyl)-3-butanol, and other aliphatic triols (having 8 to 24 carbon atoms); and low molecular weight polyols having four or more hydroxyl groups such as tetramethylolmethane, D-sorbitol, xylitol, D-mannitol, and D-mannite.

[0044] The polyester polyol can be obtained by a known esterification reaction, i.e., a condensation reaction between a polyhydric alcohol and a polybasic acid, a transesterification reaction between a polyhydric alcohol and an alkyl ester of a polybasic acid, etc. Examples of the polybasic acid or its alkyl ester include aliphatic dicarboxylic acids such as adipic acid, sebacic acid, succinic acid, azelaic acid, dimer acid, and dodecanedioic acid; alicyclic dicarboxylic acids such as hexahydrophthalic acid and tetrahydrophthalic acid; aromatic dicarboxylic acids such as isophthalic acid, terephthalic acid, orthophthalic acid, and naphthalenedicarboxylic acid; dialkyl esters thereof (e.g., alkyl esters having 1 to 6 carbon atoms), acid anhydrides thereof, and mixtures thereof. can be.

[0045] [Polyolefin resin] The coating layer preferably contains a polyolefin resin from the viewpoint of further suppressing the occurrence of adhesive residue. When the coating layer contains a polyolefin resin, the polarity of the coating layer decreases and the adhesion between the coating layer and the pressure-sensitive adhesive layer improves, thereby further suppressing the occurrence of adhesive residue, particularly during high-speed peeling. The polyolefin resin contained in the coating layer is not particularly limited, but is usually a homopolymer of an olefin compound or a copolymer with other compounds.

[0046] The softening point of the polyolefin resin contained in the coating layer is not particularly limited, but from the viewpoint of suppressing adhesive residue, it is preferably 0° C. or higher, more preferably 20° C. or higher, even more preferably 25° C. or higher, and particularly preferably 30° C. or higher, and from the viewpoint of coating film formability, it is preferably 100° C. or lower, more preferably 60° C. or lower, even more preferably 55° C. or lower, and particularly preferably 50° C. or lower. A softening point below 0° C. is more effective in suppressing adhesive residue, while a softening point above 100° C. is less likely to cause defects and makes it easier to form a coating film. The softening point is a value measured and calculated based on the method described in the examples below.

[0047] The number average molecular weight Mn of the polyolefin resin is not particularly limited, but is preferably 1,000 or more, more preferably 2,000 or more, and is preferably 1,000,000 or less, more preferably 500,000 or less.

[0048] The content of the polyolefin resin in the coating layer is not particularly limited, but is preferably 40% by mass or more, more preferably 45% by mass or more, even more preferably 48% by mass or more, and particularly preferably 50% by mass.

[0049] Examples of homopolymers of olefin compounds include homopolymers of α-olefins having 2 to 20 carbon atoms, such as polyethylene (low-density polyethylene, medium-density polyethylene, high-density polyethylene, linear low-density polyethylene, etc.), polypropylene, polyisobutylene, poly(1-butene), poly(1-pentene), and poly(1-hexene).

[0050] Examples of copolymers of olefin compounds include ethylene-propylene copolymers, ethylene-1-butene copolymers, ethylene-1-octene copolymers, and ethylene-1-hexene copolymers.

[0051] Furthermore, polyolefin resins having polar groups introduced therein can also be used as the polyolefin resin. Specific examples of polyolefin resins having polar groups introduced therein include acid-modified polyolefins such as maleic anhydride-modified polyethylene, maleic acid-modified polyethylene, acrylic acid-modified polyethylene, maleic anhydride-modified polypropylene, maleic acid-modified polypropylene, maleic anhydride-modified ethylene-propylene copolymer, and acrylic acid-modified polypropylene; ethylene-vinyl chloride copolymer, ethylene-vinylidene chloride copolymer, ethylene-acrylonitrile copolymer, ethylene-methacrylonitrile copolymer, ethylene-vinyl acetate copolymer, ethylene-acrylamide copolymer, ethylene-methacrylamide copolymer, ethylene-acrylic acid copolymer, ethylene-methacrylic acid copolymer, ethylene-maleic acid copolymer, ethylene-methyl (meth)acrylate copolymer, and ethylene-ethyl (meth)acrylate copolymer. copolymers, ethylene or α-olefin-vinyl monomer copolymers such as ethylene-isopropyl (meth)acrylate copolymer, ethylene-(meth)acrylate copolymer, ethylene-isobutyl (meth)acrylate copolymer, ethylene-2-ethylhexyl (meth)acrylate copolymer, ethylene-maleic anhydride copolymer, ethylene-ethyl acrylate-maleic anhydride copolymer, ethylene-(meth)acrylic acid metal salt copolymer, ethylene-vinyl acetate copolymer or saponification product thereof, ethylene-vinyl propionate copolymer, ethylene-glycidyl (meth)acrylate copolymer, ethylene-ethyl acrylate-glycidyl methacrylate copolymer, ethylene-vinyl acetate-glycidyl methacrylate copolymer; chlorinated polyolefins such as chlorinated polypropylene and chlorinated polyethylene.

[0052] (other resins) The coating layer may contain resins other than polyester-based resins as long as the effects of the present invention are not impaired. As the other resin, known resins used for forming a coating layer can be used depending on the rubber, resin, etc. for forming the hot melt pressure sensitive adhesive layer provided on the coating layer described below. Specific examples of other resins include thermoplastic resins such as acrylic resins, acrylic-modified polyolefin resins, chlorinated polyolefin resins, vinyl chloride-vinyl acetate copolymers, polyamide resins, and rubber-based resins; thermosetting resins such as epoxy resins; etc. These may be used alone or in combination of two or more.

[0053] The content of other resins in the coating layer is not particularly limited, but is preferably 20% by mass or less, more preferably 10% by mass or less, even more preferably 5% by mass or less, and particularly preferably 1% by mass or less, and may not be present at all.

[0054] (Crosslinking agent) The coating layer may contain a crosslinking agent as long as the effect of the present invention is not impaired. Examples of crosslinking agents include polyisocyanate compounds having two or more isocyanate groups per molecule, and more specifically, examples thereof include aromatic polyisocyanates such as tolylene diisocyanate, diphenylmethane diisocyanate, and xylylene diisocyanate; alicyclic isocyanate compounds such as dicyclohexylmethane-4,4'-diisocyanate, bicycloheptane triisocyanate, cyclopentylene diisocyanate, cyclohexylene diisocyanate, methylcyclohexylene diisocyanate, and hydrogenated xylylene diisocyanate; and aliphatic isocyanates such as hexamethylene diisocyanate, trimethylhexamethylene diisocyanate, and lysine diisocyanate. These may be used alone or in combination of two or more.

[0055] In addition, as the crosslinking agent, modified products such as biuret products and isocyanurate products of the above polyisocyanate compounds, and adduct products which are reaction products of these polyisocyanate compounds with non-aromatic low-molecular-weight active hydrogen-containing compounds such as ethylene glycol, trimethylolpropane, and castor oil can also be used.

[0056] Examples of crosslinking agents other than polyisocyanate compounds include carbodiimide crosslinking agents, oxazoline crosslinking agents, and epoxy crosslinking agents.

[0057] The content of the crosslinking agent in the coating layer is not particularly limited, but is preferably 15% by mass or less, more preferably 10% by mass or less, and particularly preferably 8% by mass or less.

[0058] (Other additives) The coating layer may contain additives other than the crosslinking agent as long as the effects of the present invention are not impaired. Other additives can be appropriately selected depending on the application of the coating layer, and examples thereof include fillers, pigments, colorants, metal powders, conductive materials, softeners (plasticizers), surfactants, dispersants, neutralizing agents, thickeners, wetting agents, antifoaming agents, slipping agents, antistatic agents, preservatives, antioxidants, ultraviolet absorbers, etc. These may be used alone or in combination of two or more.

[0059] The content of other additives in the coating layer is not particularly limited, but is preferably 20% by mass or less, more preferably 10% by mass or less, even more preferably 5% by mass or less, and particularly preferably 1% by mass or less.

[0060] <Base material> The substrate can be appropriately selected depending on the application of the pressure-sensitive adhesive sheet, and examples thereof include polyester-based resin films, polyolefin-based resin films, resin films such as synthetic paper, paper substrates, etc. Among these, resin films are preferred.

[0061] The thickness of the substrate is appropriately set depending on the application of the pressure-sensitive adhesive sheet, but from the viewpoints of ease of handling and economy, it is preferably 5 to 250 μm, more preferably 15 to 200 μm, and particularly preferably 25 to 150 μm. The thickness of the substrate is specifically a value measured and calculated based on the same method as that for the thickness of the coating layer.

[0062] [Resin film] Examples of resins contained in the resin film include polyolefin resins such as polyethylene, polypropylene, and ethylene-propylene copolymer; polyester resins such as polyethylene terephthalate, polybutylene terephthalate, and polyethylene naphthalate; urethane resins such as polyurethane and acrylic-modified polyurethane; vinyl resins such as polyvinyl chloride, polyvinylidene chloride, polyvinyl alcohol, ethylene-vinyl acetate copolymer, and ethylene-vinyl alcohol copolymer; polystyrene resin; acrylonitrile-butadiene-styrene (ABS) resin; cellulose triacetate resin; polycarbonate resin; acetate resin; polyamide resin; and polyimide resin. Among these, polyester resins are preferred, and the substrate of the present invention is preferably a resin film containing a polyester resin. These may be used alone or in combination of two or more. Synthetic paper may also be used as the resin film.

[0063] The resin content in the resin film is not particularly limited, but is preferably 80% by mass or more, more preferably 90% by mass or more, even more preferably 95% by mass or more, and particularly preferably substantially 100% by mass.

[0064] In addition to the above resin, the resin film may further contain additives such as fillers, ultraviolet absorbers, light stabilizers, antioxidants, antistatic agents, slip agents, antiblocking agents, and colorants.

[0065] The resin film may be a laminate of a plurality of resin films, or may be a foam.

[0066] <Metal deposition layer> The metal vapor deposition layer is not particularly limited, and examples thereof include a layer formed by vapor deposition of at least one of a metal and a metal oxide. Examples of metals contained in the metal vapor deposition layer include aluminum, zinc, tin, copper, nickel, chromium, silver, gold, iron, bismuth, titanium, indium, palladium, vanadium, tungsten, manganese, tantalum, and cobalt. Examples of the metal oxide contained in the metal vapor deposition layer include aluminum oxide, indium oxide, tin oxide, titanium oxide, silicon oxide, antimony oxide, bismuth oxide, and zinc oxide. In one embodiment of the present invention, from the viewpoints of usability in a variety of applications and being excellent in terms of cost and environment, the metal vapor deposition layer preferably contains aluminum, and is more preferably an aluminum vapor deposition layer. The metal vapor deposition layer may be a single metal vapor deposition layer or a laminated film in which a plurality of metal vapor deposition layers are laminated.

[0067] Methods for forming a metal vapor deposition layer on a substrate include, for example, vacuum deposition, electron beam vacuum deposition, PVD, sputtering, ion plating, thermal CVD, plasma CVD, and photo CVD. When a resin film is used as the substrate, the surface of the resin film may be subjected to a surface treatment such as oxidation or roughening in order to improve the adhesion between the resin film and the metal vapor deposition layer. The oxidation method is not particularly limited, and examples thereof include corona discharge treatment, plasma treatment, chromic acid oxidation (wet), flame treatment, hot air treatment, and ozone / ultraviolet irradiation treatment. The method for forming the irregularities is not particularly limited, and examples thereof include sandblasting and solvent treatment.

[0068] The thickness of the metal vapor deposition layer is set appropriately depending on the application of the pressure-sensitive adhesive sheet, but is usually 1 to 300 nm. The metal oxide-containing vapor-deposited layer may be a metal oxide itself or a metal oxide layer having an oxide film formed on the surface thereof. The oxide film may be naturally formed on the surface of the metal vapor-deposited layer or may be artificially formed by electrochemical treatment or the like.

[0069] <Hot melt adhesive layer> The hot-melt pressure-sensitive adhesive layer contains rubber. The hot-melt pressure-sensitive adhesive layer is formed by heating and melting a thermoplastic resin such as an acrylic or olefin in addition to rubber, and applying the same. If necessary, the hot-melt pressure-sensitive adhesive layer may contain a softener, a tackifier resin, other additives, and the like. In one embodiment of the present invention, the hot melt pressure-sensitive adhesive layer is preferably a layer containing a tackifier resin. The thickness of the hot melt pressure sensitive adhesive layer is not particularly limited, but is preferably 1 to 200 μm, more preferably 5 to 150 μm, and particularly preferably 10 to 100 μm. The thickness of the hot-melt pressure-sensitive adhesive layer is specifically a value measured and calculated based on the same method as that for the thickness of the coating layer.

[0070] (rubber) Examples of rubber that can be contained in the hot melt pressure-sensitive adhesive layer include natural rubbers such as RSS-No. 1 to 4, SMR-5L, SMR-20, and CV-60; and synthetic rubbers such as styrene-isoprene-styrene block copolymer (SIS) rubber, styrene-butadiene rubber, butadiene rubber, chloroprene rubber, and nitrile rubber. These may be used alone or in combination of two or more. Since most rubbers have a large molecular weight, the molecular weight is mechanically reduced using a mixing roll, Banbury kneader, kneader, etc. to improve initial tack and coatability.

[0071] (softener) The softener contained in the hot-melt pressure-sensitive adhesive layer reduces the viscosity of the hot-melt pressure-sensitive adhesive to improve its coatability, and examples thereof include petroleum-based softeners such as process oil and extender oil, vegetable oil-based softeners such as tall oil, synthetic plasticizers such as dibasic acid ester-based plasticizers, etc. These may be used alone or in combination of two or more.

[0072] (tackifying resin) The tackifier that may be contained in the hot melt adhesive layer serves to increase the initial tack and adhesive strength. Examples of tackifying resins include rosin-based resins, ester compounds of rosin-based resins with pentaerythritol, terpene resins including polymers of terpenes such as α-pinene and β-pinene, and copolymers thereof; terpene-modified resins such as terpene-phenolic resins; petroleum resins such as aromatic hydrocarbon resins and aliphatic hydrocarbon resins (for example, aliphatic / aromatic copolymer petroleum resins) and hydrogenated versions thereof; phenolic resins such as coumarone-indene resins and alkylphenol-acetylene resins; etc. These may be used alone or in combination of two or more.

[0073] (Other additives) Other additives that can be contained in the hot melt pressure-sensitive adhesive layer include, for example, fillers such as calcium carbonate and clay, pigments, antioxidants, etc. These may be used alone or in combination of two or more.

[0074] Examples of the device for mixing the above components include a Banbury kneader, a kneader, a twin-screw kneading extruder, etc. These may be used alone or in combination of two or more. When it is necessary to reduce the molecular weight of the rubber, the softener, tackifying resin, and other additives may be mixed after the rubber has been reduced in molecular weight, or may be mixed simultaneously with the reduction of the molecular weight of the rubber. The temperature during mixing is not particularly limited, but from the viewpoint of uniformity, it is preferably equal to or higher than the softening point of the tackifier resin, and from the viewpoint of preventing deterioration of the rubber, it is preferably equal to or lower than 200°C.

[0075] <Release liner> The release liner is usually formed on the hot melt pressure sensitive adhesive layer on the side opposite to the coating layer. Examples of release liners include release sheets that have been treated for release on both sides and release sheets that have been treated for release on one side. The release treatment may be, for example, by applying a release agent to the surface of the release liner substrate. Examples of substrates for release liners include those that can be used as substrates for pressure-sensitive adhesive sheets, such as resin films, paper substrates, laminated paper, and synthetic paper. These may be used alone or in combination of two or more. Examples of the release agent include olefin resins, isoprene resins, butadiene resins, silicone resins, long-chain alkyl resins, alkyd resins, fluorine resins, etc. These may be used alone or in combination of two or more.

[0076] The thickness of the release liner is not particularly limited, but is preferably 10 to 200 μm, more preferably 25 to 150 μm. The thickness of the release liner is specifically a value measured and calculated based on the same method as that for the thickness of the coating layer.

[0077] <Printed coating layer> The print coating layer is usually formed on the substrate on the side opposite to the metal vapor deposition layer. The resin material for the print coat layer is not particularly limited as long as it has good adhesion to the substrate and can form a print coat layer with good adhesion to the printing ink, and examples thereof include acrylic resins, styrene resins, polyester urethane resins, polyester resins, polyurethane resins, polyol resins, polyvinyl alcohol, polyvinylpyrrolidone, cellulose derivatives, acetate derivatives, polyvinyl chloride resins, polyimide resins, etc. These may be used alone or in combination of two or more. Among these, polyester urethane resin is preferred. The polyester urethane resin may be polymerized using a crosslinking agent or a crosslinking accelerator as appropriate.

[0078] When the substrate on which the printing coating layer is formed is a resin film such as synthetic paper, the content of the resin material in the printing coating layer is not particularly limited, but is preferably 80% by mass or more, more preferably 90% by mass or more, even more preferably 95% by mass or more, and particularly preferably substantially 100% by mass.

[0079] Examples of additives that can be added to the print coating layer include pigments, colorants, metal powders, conductive materials, softeners (plasticizers), solvents, surfactants, dispersants, neutralizing agents, thickeners, wetting agents, antifoaming agents, slipping agents, antistatic agents, crosslinking agents, preservatives, antioxidants, ultraviolet absorbers, etc. These may be used alone or in combination of two or more.

[0080] The content of the additive in the print coat layer is not particularly limited, but is preferably 20% by mass or less, more preferably 10% by mass or less, and even more preferably 5% by mass or less.

[0081] The thickness of the print coat layer is not particularly limited, but is preferably 10 to 600 nm, more preferably 30 to 200 nm. The thickness of the print coat layer is specifically a value measured and calculated based on the same method as that for the thickness of the coat layer.

[0082] [Method for manufacturing pressure-sensitive adhesive sheet]

[0083] The method for producing a pressure-sensitive adhesive sheet of the present invention is a method for producing a pressure-sensitive adhesive sheet having, in this order, a substrate, a metal vapor deposition layer, a coating layer containing a polyester-based resin, and a rubber-based hot-melt pressure-sensitive adhesive layer, and includes a step of applying a coating liquid having a pH of 5 to 9 to form the coating layer. By applying a coating liquid with a pH of 5 to 9 to form a coating layer, the metal-deposited surface will not corrode even long periods after the adhesive sheet is manufactured, and the adhesive sheet will be able to fully exhibit the functions required of it (flexibility, elasticity, adhesiveness, etc.). The pH of the coating solution is preferably 5.5 or more, more preferably 6 or more, and preferably 8.5 or less, more preferably 8 or less, from the viewpoint of suppressing corrosion of the metal vapor deposition surface and obtaining better adhesion between the metal vapor deposition layer and the coating layer.

[0084] There are no particular limitations on the method for producing the pressure-sensitive adhesive sheet, as long as it includes a step of applying a coating liquid having a pH of 5 to 9 to form a coating layer, but a preferred example is shown below. For example, the adhesive sheet 1a in FIG. 1 can be produced by depositing a material capable of forming a metal vapor deposition layer on a substrate 11 by a known deposition method to form a metal vapor deposition layer 12, then applying a coating liquid having a pH of 5 to 9 capable of forming a coating layer containing the above-mentioned polyester-based resin on the metal vapor deposition layer by a known coating method, drying the coating layer to form a coating layer 13, and then further applying the above-mentioned hot melt adhesive on the coating layer 13 by a known coating method to form a hot melt adhesive layer 14. Furthermore, adhesive sheet 1b of FIG. 2 can be produced by laminating release liner 15 on hot melt adhesive layer 14 of adhesive sheet 1a of FIG. 1 produced by the above method. The adhesive sheet 1b in Figure 2 can also be produced by bonding together a hot-melt adhesive layer 14 formed on a release liner 15 by the above-mentioned method and a coating layer 13 formed on a substrate 11 by the above-mentioned method. Furthermore, a print coat layer (not shown) may be formed on the substrate 11 of the adhesive sheet 1a of FIG. 1 or the adhesive sheet 1b of FIG. 2 produced by the above method.

[0085] From the viewpoints of reducing environmental impact and the occurrence of adhesive residue, the method for producing a pressure-sensitive adhesive sheet preferably includes a step of applying to a substrate an aqueous coating liquid in which a polyester resin is dispersed in water, the aqueous coating liquid having a pH of 5 to 9. The aqueous coating liquid in which a polyester resin is dispersed in water may contain a solvent as described below, and the above solvents may be used alone or in combination of two or more, but it is preferable that the coating liquid does not contain a solvent. Furthermore, even when the coating layer further contains at least one of a polyurethane resin and a polyolefin resin, it is preferable to include a step of applying to the substrate an aqueous coating liquid having a pH of 5 to 9 in which a polyester resin and at least one of a polyurethane resin and a polyolefin resin are dispersed in water. In the case of a layer formed by applying an aqueous coating liquid to a substrate, a small amount of an emulsifier, surfactant, or the like may be used to disperse the polyester resin in water, as long as the effects of the present invention are not impaired. However, low-molecular-weight components such as emulsifiers and surfactants may become localized in the coating layer, reducing adhesiveness and causing a decrease in interlayer adhesion, which can result in adhesive residue remaining on the adherend when the pressure-sensitive adhesive sheet is peeled from the adherend, or the pressure-sensitive adhesive layer protruding when the pressure-sensitive adhesive sheet is cut. From the viewpoint of suppressing the above-mentioned phenomenon, in one embodiment of the present invention, the polyester-based resin is preferably a self-emulsifying polyester-based resin. The self-emulsifying polyester resin can form an emulsion without using low-molecular-weight components such as emulsifiers and surfactants, which can cause a decrease in interlayer adhesion, and therefore the interlayer adhesion of the resulting pressure-sensitive adhesive sheet can be further improved.Furthermore, the pressure-sensitive adhesive sheet is also excellent in preventing the pressure-sensitive adhesive layer from protruding when cut. The term "self-emulsifying" means that some kind of hydrophilic group is chemically introduced into the resin skeleton, and the resin itself has emulsifying ability without the need for the addition of an emulsifier or surfactant.

[0086] Examples of solvents that may be contained in the aqueous coating liquid include methanol, ethanol, propanol, butanol, isopropyl alcohol, dimethylacetamide, ethylene glycol, ethylene glycol mono-n-propyl ether, propylene glycol monomethyl ether, propylene glycol monomethyl ether acetate, etc. These may be used alone or in combination of two or more.

[0087] Furthermore, in order to improve application properties and work efficiency, materials that can form a printing coating layer may be applied to a substrate in the form of a solution by adding a solvent, or may be applied in the form of a dispersion in which the material is dispersed in water. The solvent is not particularly limited and may be appropriately selected depending on the type of material capable of forming the above-mentioned print coating layer.

[0088] Examples of methods for applying materials that can form a coating layer and materials that can form a printing coating layer include spin coating, spray coating, bar coating, knife coating, air knife coating, roll knife coating, roll coating, blade coating, die coating, gravure coating, lip coating, and curtain coating. Examples of methods for applying a material capable of forming a hot melt pressure-sensitive adhesive layer include spray coating, bar coating, knife coating, air knife coating, roll knife coating, roll coating, blade coating, die coating, gravure coating, lip coating, and curtain coating. Furthermore, the drying temperature and drying time of the coating film formed after application of the coating layer and the printed coating layer are not particularly limited and can be set appropriately. [Example]

[0089] The present invention will be specifically described with reference to the following examples, but the present invention is not limited to these examples. The various physical property values ​​of the resins (polyester-based resin, polyurethane-based resin, and polyolefin-based resin) contained in the coating layer below were measured by the following methods. The pressure-sensitive adhesive sheets prepared in the examples and comparative examples were also evaluated for the following "metal vapor deposition layer / coating layer adhesion," "removability," and "appearance after accelerated heat and humidity testing." The results are shown in Table 1.

[0090] (1) Glass transition temperature (Tg) of resin The glass transition temperature (°C) of the resin used to form the barrier layer was measured in accordance with JIS K 7121 (2012) using a differential scanning calorimeter (manufactured by TA Instruments Japan, product name "DSC Q2000") at a heating rate of 20°C / min. (2) Softening point of resin The softening point (°C) of the resin used to form the barrier layer was measured based on the softening point test method (ring and ball method) specified in JIS K 5601-2-2 (1999). (3) Hydroxyl value of resin The hydroxyl value (KOH mg / g) of the resin used to form the barrier layer was measured in accordance with JIS K 0070 (1992). (4) Acid value of resin The acid value (KOH mg / g) of the resin used to form the barrier layer was measured in accordance with JIS K 0070 (1992).

[0091] (5) Metal deposition layer / coating layer adhesion The adhesive sheets produced in the Examples and Comparative Examples were evaluated for adhesion at the interface between the metal vapor deposition layer and the coating layer in accordance with JIS K5600-5-6 (1999) according to the following criteria. 〇: Classification according to JIS K5600-5-6(1999) is "0 (best)" to "1" ×: Classification according to JIS K5600-5-6 (1999) is "2" to "5" (6)Removability The pressure-sensitive adhesive sheets produced in the Examples and Comparative Examples were cut to 25 mm x 50 mm in an environment of 23°C and 50% RH (relative humidity) to prepare two test pieces (I) for each. The release sheets were removed from the test pieces (I), and the exposed pressure-sensitive adhesive layers were attached to the following adherends. Stainless steel (SUS) plate Then, the test pieces (I) attached to the adherend were left to stand for 7 days in an environment of 23°C and 50% RH (relative humidity), after which one of the test pieces (I) was peeled off by hand from the adherend in a 180° direction at a speed of approximately 300 mm / min (slow-speed peeling), and the other was peeled off by hand in a 180° direction at a speed of approximately 30 m / min (high-speed peeling). Then, the state of each layer of the test piece (I) after peeling was visually observed, and the interlayer adhesion (removability) of the pressure-sensitive adhesive sheet was evaluated according to the following criteria. A: The adhesive layer is peeled off from the adherend, and no adhesive layer remains on the adherend, demonstrating excellent removability. B: The metal vapor deposition layer and the coating layer were peeled off, and residues of the coating layer and adhesive layer were found on the adherend. C: Peeling occurred between the coating layer and the adhesive layer, and the adhesive layer was confirmed to remain on the adherend. D: The metal vapor deposition layer and the adhesive layer were peeled off, and the adhesive layer was found to remain on the adherend. (7) Appearance after humid heat acceleration The pressure-sensitive adhesive sheets produced in the examples and comparative examples were left to stand for 7 days in an environment of 60°C and 95% RH (relative humidity), and then the appearance was visually observed and evaluated according to the following criteria. ·〇: No significant changes were observed. · △: The metal vapor deposition layer is corroded and there are a few areas where the metal vapor deposition layer has become transparent. ·×: The metal vapor deposition layer was corroded, and many areas where the metal vapor deposition layer had become transparent were observed.

[0092] The aqueous resin 1 dispersion and aqueous resin 2 dispersion used in the present examples and comparative examples are as follows: The glass transition temperature, softening point, hydroxyl value, and acid value were measured by the methods described in (1), (2), (3), and (4) above. (i) "Polyester resin" (glass transition temperature: 46°C, hydroxyl value: 5 KOHmg / g, acid value: 50 KOHmg / g) (ii) "Polyurethane resin" (glass transition temperature: 85°C, acid value: 18KOHmg / g) (iii) "Polyolefin resin" (softening point: 40°C)

[0093] [Example 1] The substrate was a polyethylene terephthalate film and aluminum (Al) was deposited on it as a metal deposition layer. This PET film, "Metal Me TS" (manufactured by Toray Industries, Inc., thickness: 50 μm), was used. An aqueous resin dispersion for forming a coating layer, prepared by dispersing a "polyester resin" (glass transition temperature: 46°C, hydroxyl value: 5 KOHmg / g, acid value: 50 KOHmg / g) in water, with a solids concentration of 10 mass% and a pH of 7, was applied onto the aluminum-deposited surface of the substrate to form a coating film, which was then dried at 90°C for 1 minute to form a coating layer with a thickness of 1 μm. Next, a synthetic rubber-based hot-melt adhesive composition "Toyomelt P-708K-5" (manufactured by Toyo ADL Co., Ltd.) melted at 150°C was applied to a release liner (polyethylene terephthalate substrate coated with a silicone-based release agent, thickness: 50 μm) using a die coater to form a hot-melt adhesive layer with a thickness of 20 μm. The coating layer and the hot-melt adhesive layer were then laminated to produce an adhesive sheet. The pressure-sensitive adhesive sheets thus produced were evaluated for adhesion between the metal deposition layer and the coating layer, removability, and appearance after accelerated exposure to heat and humidity. The evaluation results are shown in Table 1 below.

[0094] [Examples 2 and 3] In Example 1, a pressure-sensitive adhesive sheet was produced in the same manner as in Example 1, except that instead of the aqueous resin dispersion used in Example 1, an aqueous resin dispersion for forming a coating layer with a solids concentration of 10% by mass was used, which was a 1:1 mixture of aqueous resin 1 dispersion and aqueous resin 2 dispersion, each having a pH shown in Table 1 below. The adhesiveness between the metal vapor deposition layer and the coating layer, removability, and appearance after accelerated moist heat treatment were evaluated. The results are shown in Table 1. The pH of the aqueous resin dispersion for forming a coating layer used in Example 2 was 7.5, and the pH of the aqueous resin dispersion for forming a coating layer used in Example 3 was 8.5.

[0095] [Comparative Example 1] An adhesive sheet was produced in the same manner as in Example 1, except that a hot-melt adhesive layer was formed directly on the aluminum vapor-deposited surface of the substrate without forming a coating layer, and the adhesiveness between the metal vapor-deposited layer and the coating layer, removability, and appearance after accelerated heat and humidity treatment were evaluated. The results are shown in Table 1.

[0096] [Comparative Examples 2 and 3] Pressure-sensitive adhesive sheets were prepared in the same manner as in Example 1, except that an aqueous resin 1 dispersion having a pH shown in Table 1 below was used instead of the aqueous resin 1 dispersion used in Example 1, and the metal vapor deposition layer / coating layer adhesion, removability, and appearance after accelerated moist heat treatment were evaluated. The results are shown in Table 1.

[0097] [Table 1]

[0098] From Table 1, it was found that by disposing a coating layer containing a polyester resin between the metal vapor deposition layer and the hot melt adhesive layer, it is possible to prevent adhesive residue from being left behind when peeling them off. [Industrial Applicability]

[0099] The pressure-sensitive adhesive sheet of the present invention can be used as a pressure-sensitive adhesive sheet for a wide range of applications, such as display labels, decorative labels, package films, window films, electromagnetic wave shielding labels, packaging, and sheets for electrical equipment. [Explanation of symbols]

[0100] 1a, 1b Adhesive sheet 11 Base material 12 Metal deposited layer 13 Coating layer 14 Hot melt adhesive layer 15 Release Liner

Claims

1. A pressure-sensitive adhesive sheet having a substrate, a metal vapor-deposited layer, and a rubber-based hot-melt pressure-sensitive adhesive layer in this order, The adhesive tape further includes a coating layer containing a polyester resin and disposed between the metal vapor deposition layer and the rubber-based hot-melt pressure-sensitive adhesive layer, The pressure-sensitive adhesive sheet, wherein the coating layer further contains at least one of a polyurethane resin and a polyolefin resin.

2. The pressure-sensitive adhesive sheet according to claim 1 , wherein the metal vapor deposition layer is an aluminum vapor deposition layer.

3. The pressure-sensitive adhesive sheet according to claim 1 or 2, wherein the substrate is a resin film containing a polyester-based resin.

4. The pressure-sensitive adhesive sheet according to any one of claims 1 to 3, wherein the polyester resin contained in the coating layer has a glass transition temperature of 20 to 80°C.

5. The pressure-sensitive adhesive sheet according to any one of claims 1 to 4, further comprising a release liner on the rubber-based hot-melt pressure-sensitive adhesive layer on the side opposite to the coating layer.

6. A method for producing a pressure-sensitive adhesive sheet having, in this order, a substrate, a metal vapor deposition layer, a coating layer containing a polyester resin, and a rubber-based hot-melt pressure-sensitive adhesive layer, comprising: The coating layer further contains at least one of a polyurethane resin and a polyolefin resin. A method for producing a pressure-sensitive adhesive sheet, comprising a step of applying a coating liquid having a pH of 5 or more and a pH of 9 or less to form a coating layer.

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