Adhesive for electronic tags and electronic tags

Abstract

The present invention pertains to an electronic tag adhesive and an electronic tag. The electronic tag adhesive includes a thermoplastic elastomer and fulfills conditions (1) and (2).　(1) The dielectric constant of a layer obtained from the adhesive and measured at a frequency of 1 kHz is no more than 4. (2) The dielectric tangents for a layer obtained from the adhesive and measured at frequencies of 1 kHz, 10 kHz, 100 kHz, 1 MHz, and 10 GHz are no more than 0.10, respectively.

Description

Technical Field

[0001] One embodiment of the present invention relates to an adhesive for an electronic tag or an electronic tag.

Background Art

[0002] Generally, an electronic tag such as a non-contact IC tag has an IC chip and an antenna in which identification information of each article is input in advance. The electronic tag is used by being attached or embedded in an article. For example, in the industrial field, an electronic tag is attached to an article to identify and manage the article (Electronic Article Sureillannce, EAS). For example, a non-contact IC tag mainly enables a communication distance of several meters by wireless using UHF waves including microwaves, and the article is identified and managed by this communication.

[0003] As a method for manufacturing an electronic tag, for example, a method is known in which a circuit pattern is formed of a conductive substance on one surface of a base material, an IC chip is mounted thereon to form an electronic circuit, and a surface film having an adhesive layer is laminated on the electronic circuit by being bonded thereto to manufacture an electronic tag. In addition, in an electronic tag manufacturing line, using a long manufacturing apparatus, each IC module is continuously manufactured in a series state, rolled up, and separated for each IC module at the time of use to obtain a large number of electronic tags.

[0004] As the adhesive for forming the adhesive layer, various adhesives are used. For example, Patent Document 1 discloses an IC tag in which an electronic circuit sheet having an electronic circuit composed of a circuit line and an IC chip connected to the circuit is sequentially covered with a specific buffer material and a surface layer on one surface of a base material sheet, and an IC tag in which the base material sheet and the electronic circuit are laminated via an adhesive layer is disclosed.

Prior Art Documents

Patent Documents

[0005] Patent Document 1 Japanese Patent No. 4274867 Summary of the Invention Problems to be Solved by the Invention

[0006] However, the adhesive layer formed from a conventional adhesive for electronic circuits such as the adhesive described in Patent Document 1 has insufficient insulation and a large dielectric loss. Therefore, for an electronic tag using such an adhesive layer, the communication distance may be shortened. In addition, since the adhesive layer formed from a conventional adhesive for electronic circuits has low water resistance, when an electronic tag using such an adhesive layer is used in a high-humidity environment, the operation of the electronic tag may become unstable due to the influence of water, which is a substance with high radio wave absorption.

[0007] Furthermore, the adhesive layer formed from a conventional adhesive for electronic circuits had low chemical resistance. Therefore, when a metal material was laminated on one side of a base material via an adhesive layer and the metal material was etched to form a circuit pattern, the adhesive layer might peel off during the etching. Also, the adhesive layer formed from a conventional adhesive for electronic circuits had strong tackiness. For this reason, for example, there may be a case where it is desired to wind up a surface film with an adhesive layer obtained by coating an adhesive on the surface film. However, if it is wound up in this way, it will stick and cannot be stretched later, so eventually it may not be possible to wind it up.

[0008] One embodiment of the present invention provides an adhesive suitable for an electronic tag and an electronic tag using the same. Means for Solving the Problems

[0009] According to the following configuration example, it was found that the above problems can be solved, and the present invention was completed. The configuration example of the present invention is as follows.

[0010] [1] An adhesive for electronic tags, comprising a thermoplastic elastomer and satisfying the following requirements (1) and (2). (1) The relative permittivity measured at a frequency of 1 kHz of the layer obtained from the adhesive is 4 or less. (2) The dielectric loss tangent measured at frequencies of 1 kHz, 10 kHz, 100 kHz, 1 MHz, and 10 GHz of the layer obtained from the adhesive is all 0.10 or less.

[0011] [2] The adhesive for electronic tags according to [1], wherein the thermoplastic elastomer is one or more thermoplastic elastomers selected from olefin-based elastomers and styrene-based elastomers.

[0012] [3] The adhesive for electronic tags according to [1] or [2], wherein the thermoplastic elastomer includes a modified thermoplastic elastomer modified with a monomer having a functional group. [4] The adhesive for electronic tags according to [3], wherein the functional group is a carboxyl group and / or an acid anhydride group.

[0013] [5] The thermoplastic elastomer is an olefin-based elastomer containing a polymer derived from an α-olefin having 2 to 20 carbon atoms, the polymer derived from the α-olefin having 2 to 20 carbon atoms contains a structural unit derived from an α-olefin having 4 to 20 carbon atoms, the olefin-based elastomer has a heat of fusion of 0 to 50 J / g measured according to JIS K7122, The adhesive for electronic tags according to any one of [1] to [4].

[0014] [6] The adhesive for electronic tags according to any one of [1] to [5], further comprising a polar component other than the modified thermoplastic elastomer modified with a monomer having a functional group. [7] The adhesive for electronic tags according to any one of [1] to [6], further comprising a hydrocarbon-based synthetic oil.

[0015] [8] An electronic tag having at least one electronic member selected from circuit lines and IC chips through an adhesive layer formed of the adhesive for electronic tags according to any one of [1] to [7] on a substrate.

[0016] [9] An electronic tag in which at least one electronic member selected from circuit lines and IC chips is disposed on a substrate, has a surface layer on the side opposite to the substrate of the electronic member, and the electronic member and the surface layer are adhered with the adhesive for electronic tags according to any one of [1] to [7].

[0017]

[10] An electronic tag in which at least one electronic member selected from circuit lines and IC chips is disposed on a substrate, has a surface layer on the side opposite to the substrate of the electronic member, and the substrate and the surface layer are adhered with the adhesive for electronic tags according to any one of [1] to [7]. [Advantages of the Invention]

[0018] According to one embodiment of the present invention, there can be provided an adhesive for electronic tags, preferably for non-contact IC tags (RFID tags), capable of forming an adhesive layer that is excellently balanced in high insulation, low dielectric loss, water resistance, chemical resistance, adhesive strength, and low tackiness. Further, according to one embodiment of the present invention, an electronic tag having a long communication distance and operating stably even in a high humidity environment can be easily obtained. [Brief Description of the Drawings]

[0019]

Figure 1

Figure 2

Figure 3

[0020] ≪Adhesive for Electronic Tags≫ The adhesive for electronic tags according to one embodiment of the present invention (hereinafter also referred to as "this adhesive") contains a thermoplastic elastomer and satisfies the following requirements (1) and (2). (1) The relative permittivity measured at a frequency of 1 kHz of the layer obtained from this adhesive is 4 or less. (2) The dielectric tangent measured at frequencies of 1 kHz, 10 kHz, 100 kHz, 1 MHz, and 10 GHz of the layer obtained from this adhesive is all 0.10 or less.

[0021] This adhesive may be used in any part of the electronic tag. Also, it may be used in two or more layers of the electronic tag. For example, use between the base material and the electronic member (adhesive layer 6 below), between the electronic member and the surface layer (adhesive layer 2 below), between the base material and the surface layer (adhesive layer 2 below), between the base material and the support (adhesive layer 7 below), and between the base material and the release layer can be mentioned.

[0022] This adhesive has a relative permittivity measured at a frequency of 1 kHz of the layer obtained from the adhesive of 4 or less, preferably 3 or less, more preferably 2.5 or less, and particularly preferably 2 or less.

[0023] This adhesive has a dielectric tangent measured at frequencies of 1 kHz, 10 kHz, 100 kHz, 1 MHz, and 10 GHz of the layer obtained from the adhesive of all 0.10 or less, preferably all 0.020 or less, more preferably 0.010 or less, and even more preferably all 0.0050 or less.

[0024] The adhesive that satisfies the above requirements (1) and (2) has high insulation and small dielectric loss, so the communication distance of the electronic tag obtained when used as an adhesive for electronic tags can be lengthened. The method for measuring the relative permittivity and dielectric tangent of this adhesive and the method for preparing the sample for measurement are as described in the examples below. The adhesive that satisfies the above requirements (1) and (2) can be easily obtained, for example, by using a thermoplastic elastomer in the following content.

[0025] This adhesive preferably further satisfies the following requirements (3) and / or (4), and more preferably satisfies the following requirements (3) and (4). (3) The absolute value of the difference between the relative permittivity measured at a frequency of 1 kHz and the relative permittivity measured at a frequency of 10 GHz of the layer obtained from this adhesive is preferably 1 or less, more preferably 0.1 or less. (4) The difference between the maximum value and the minimum value of the dielectric loss tangent measured at frequencies of 1 kHz, 10 kHz, 100 kHz, 1 MHz, and 10 GHz of the layer obtained from this adhesive is preferably 0.02 or less, more preferably 0.01 or less, and particularly preferably 0.0020 or less.

[0026] When the above (3) and / or (4) are satisfied, the relative permittivity and the dielectric loss tangent have little frequency dependence, and the electronic tag can be used in a wide frequency range.

[0027] <Thermoplastic elastomer> This adhesive contains a thermoplastic elastomer. Examples of the thermoplastic elastomer include olefin-based elastomers and styrene-based elastomers, and the olefin-based elastomer and the styrene-based elastomer can be used in combination at an arbitrary ratio. Further, the thermoplastic elastomer is preferably a modified thermoplastic elastomer modified with a monomer having a functional group. The thermoplastic elastomer contained in this adhesive may be one kind or two or more kinds.

[0028] The content of the thermoplastic elastomer may be 100% by mass based on 100% by mass of the non-volatile content (components other than the solvent) of this adhesive. In this case, it is preferable to use an olefin-based elastomer and a styrene-based elastomer as the thermoplastic elastomer, and it is more preferable to use a modified olefin-based elastomer and a modified styrene-based elastomer. Furthermore, as the thermoplastic elastomer, it is more preferable to use a modified olefin-based elastomer. When a modified styrene-based elastomer and a modified olefin-based elastomer are used in combination, the content of the modified olefin-based elastomer / the content of the modified styrene-based elastomer (mass ratio) is preferably 100 / 0 to 60 / 40, preferably 100 / 0 to 55 / 45. When the present adhesive contains the following other polar components, the content of the thermoplastic elastomer is preferably 40% by mass or more, more preferably 50% by mass or more, still more preferably 60% by mass or more, and preferably 98% by mass or less, particularly preferably 96% by mass or less, based on 100% by mass in total of the thermoplastic elastomer and the other polar components. When the content of the thermoplastic elastomer is within the above range, an adhesive layer excellent in adhesive strength and chemical resistance can be easily obtained.

[0029] 〈Olefin-based elastomer〉 Examples of the olefin-based elastomer include a polymer (a) derived from an α-olefin having 2 to 20 carbon atoms, and it is preferably a modified polymer (b) modified with a monomer having a functional group.

[0030] 〔Polymer (a) derived from an α-olefin having 2 to 20 carbon atoms〕 The polymer (a) is not particularly limited as long as it contains a structural unit derived from an α-olefin having 2 to 20 carbon atoms, and it may be a polymer composed of an α-olefin having 4 to 20 carbon atoms, or a copolymer obtained by using an α-olefin having 4 to 20 carbon atoms and an α-olefin having 2 to 3 carbon atoms. If necessary, it may also be a polymer containing a structural unit derived from an unsaturated monomer other than the α-olefin (hereinafter also referred to as "other unsaturated monomer").

[0031] When the polymer (a) has a structural unit derived from an α-olefin having 4 to 20 carbon atoms, it is preferable in terms of well-balanced excellent long-term stability, adhesive strength and chemical resistance of the adhesive containing the polymer (a) and a solvent.

[0032] The α-olefin used as a raw material for the polymer (a) may be a single type or two or more types. That is, the polymer (a) may be a homopolymer of an α-olefin having 2 to 20 carbon atoms, or may be a copolymer obtained using the α-olefin, or may be a copolymer (a1) obtained using one or more α-olefins having 4 to 20 carbon atoms and one or more α-olefins having 2 to 3 carbon atoms. Examples of the copolymer include a random copolymer and a block copolymer, and a random copolymer is preferred.

[0033] Examples of the α-olefin having 4 to 20 carbon atoms include linear or branched α-olefins such as 1-butene, 1-pentene, 1-hexene, 4-methyl-1-pentene, 1-octene, 1-decene, 1-dodecene, 1-tetradecene, 1-hexadecene, 1-octadecene, and 1-eicosene.

[0034] The α-olefin having 4 to 20 carbon atoms is preferably a linear olefin having 4 to 10 carbon atoms, more preferably a linear olefin having 4 to 6 carbon atoms, from the viewpoint of easily obtaining a polymer excellent in solubility in a solvent and strength. From the viewpoint of obtaining a polymer particularly excellent in the above effects, it is more preferably included 1-butene, and particularly preferably 1-butene.

[0035] Examples of the α-olefin having 2 to 3 carbon atoms include ethylene and propylene. From the viewpoint of easily obtaining a polymer excellent in solubility in a solvent and strength, it is preferably included propylene, and particularly preferably propylene.

[0036] Examples of the other unsaturated monomer include conjugated polyenes such as butadiene and isoprene, and non-conjugated polyenes such as 1,4-hexadiene, 1,7-octadiene, dicyclopentadiene, 5-ethylidene-2-norbornene, 5-vinyl-2-norbornene, 5-methylene-2-norbornene, and 2,5-norbornadiene.

[0037] As the polymer (a), the copolymer (a1) is preferable from the viewpoints such as being able to easily obtain a polymer excellent in solubility in a solvent and strength. A copolymer of propylene and an α-olefin having 4 to 20 carbon atoms is more preferable. In particular, a copolymer in which all the structural units excluding the structural units derived from propylene are structural units derived from the α-olefin having 4 to 20 carbon atoms is more preferable. It is further preferable that the α-olefin having 4 to 20 carbon atoms contains 1-butene, and a copolymer of 1-butene and propylene is particularly preferable.

[0038] In the polymer (a), the content ratio of the structural units derived from the α-olefin having 4 to 20 carbon atoms is preferably, for example, 5 mol% or more, more preferably 10 mol% or more, still more preferably 20 mol% or more, based on 100 mol% of the structural units derived from the α-olefin having 2 to 20 carbon atoms, preferably based on 100 mol% of all the structural units constituting the polymer (a). Also, for example, it is 100 mol% or less, preferably 60 mol% or less, more preferably 50 mol% or less, still more preferably 40 mol% or less, particularly preferably 35 mol% or less. When the content ratio of the structural units derived from the α-olefin having 4 to 20 carbon atoms satisfies the upper limit regulation, a polymer more excellent in strength can be obtained. When the lower limit regulation is satisfied, a polymer more excellent in solubility in a solvent can be obtained.

[0039] In the polymer (a), the content ratio of the structural units derived from the α-olefin having 2 to 3 carbon atoms (preferably propylene) is preferably 40 mol% or more, more preferably 50 mol% or more, still more preferably 60 mol% or more, particularly preferably 65 mol% or more, based on 100 mol% of the structural units derived from the α-olefin having 2 to 20 carbon atoms, preferably based on 100 mol% of all the structural units constituting the polymer (a). Also, it is preferably 95 mol% or less, more preferably 90 mol% or less, still more preferably 80 mol% or less. When the content ratio of the structural unit derived from an α-olefin having 2 to 3 carbon atoms satisfies the above upper limit regulation, the melting point (Tm) and heat of fusion (ΔH) of the copolymer can be decreased, and when the lower limit regulation is satisfied, a polymer having more excellent strength can be obtained.

[0040] The polymer (a) can be obtained by polymerizing an α-olefin having 2 to 20 carbon atoms in the presence of a known solid Ti catalyst, a metallocene catalyst, etc. which are usually used in the production of polymers of α-olefins. Examples of the metallocene catalyst include a catalyst containing a metallocene compound such as rac-dimethylsilylene-bis{1-(2-methyl-4-phenylindenyl)}zirconium dichloride, an organoaluminum oxy compound such as methylaluminoxane, and an organoaluminum compound such as triisobutylaluminum. More specifically, the polymer (a) can be obtained, for example, by the method described in International Publication No. 2004 / 87775.

[0041] The weight average molecular weight (Mw) in terms of standard polystyrene, measured by gel permeation chromatography (GPC) of the polymer (a) is preferably 1×10 4 or more, and preferably 1×10 7 or less, and the molecular weight distribution (Mw / Mn) is preferably 1 or more, and preferably 3 or less.

[0042] When Mw and Mw / Mn satisfy the above lower limit regulation, an adhesive layer having a sufficiently high adhesive strength can be easily obtained, and the adhesive strength between the adhesive layer and the adherend (e.g., base material, electronic member, surface layer) becomes better. When the upper limit regulation is satisfied, a polymer having good solubility in a solvent can be obtained, and an adhesive in which solidification and precipitation hardly occur can be obtained.

[0043] In the present invention, Mw and Mw / Mn can be specifically measured by the methods described in the following examples.

[0044] The melting point (Tm) of the polymer (a) is preferably less than 120°C, more preferably less than 100°C. When Tm is within the above range, even if an adhesive layer is formed from this adhesive under low-temperature curing conditions, an adhesive layer excellent in adhesive strength can be obtained.

[0045] In the present invention, Tm is determined by differential scanning calorimetry (DSC measurement) in accordance with JIS K 7122. Specifically, after raising the temperature from 30°C to 180°C at 10°C / min and holding the temperature at that level for 3 minutes, then lowering the temperature to 0°C at 10°C / min and holding the temperature at that level for 3 minutes, and then raising the temperature to 150°C again at 10°C / min, it is determined according to JIS K 7122 from the thermogram during the second temperature increase.

[0046] The heat of fusion (ΔH) of the polymer (a) is preferably 0 J / g or more, more preferably 3 J / g or more, particularly preferably 5 J / g or more, and preferably 50 J / g or less, more preferably 40 J / g or less. When ΔH satisfies the above upper limit requirement, even if an adhesive layer is formed from this adhesive under low-temperature curing conditions, an adhesive layer excellent in adhesive strength can be obtained. When it satisfies the above lower limit requirement, an adhesive layer excellent in adhesive strength can be obtained.

[0047] In the present invention, ΔH is determined by differential scanning calorimetry (DSC measurement) in accordance with JIS K 7122, and is specifically calculated from the peak area of the thermogram obtained during the temperature increase process at 10°C / min. More specifically, for the purpose of canceling the thermal history before measurement, the temperature is raised to 180°C at 10°C / min before measurement, held at that temperature for 3 minutes, then lowered to 0°C at 10°C / min and held at that temperature for 3 minutes, and then ΔH is measured.

[0048] [Modified polymer (b)] The modified polymer (b) is not particularly limited as long as it is a modified thermoplastic elastomer modified with a monomer having a functional group, but it is preferably a polymer obtained by reacting one or more monomers having a functional group with one or more of the polymers (a). The modified polymer (b) can be synthesized according to a conventional method, for example, as disclosed in International Publication No. WO 2017 / 126520.

[0049] Examples of the functional group include groups having active hydrogen, and specifically, a hydroxyl group, an amino group, a carboxyl group, an acid anhydride group, an ester group, a thiol group, etc. are included. The monomer having the functional group may have one type of functional group or may have two or more types of functional groups. Also, the number of functional groups may be one or two or more.

[0050] As the monomer having the functional group, when forming the adhesive layer, it can react efficiently, enhance the affinity for the following base material / surface layer (e.g., synthetic resin, paper) and conductive material (e.g., circuit line), and further improve the adhesive strength between the adhesive layer and the adherend. Also, from the viewpoint of being able to improve the chemical resistance of the obtained adhesive layer, etc., a monomer having an acid anhydride group or a carboxyl group is preferable.

[0051] Examples of the monomer having the functional group include a hydroxyl group-containing unsaturated compound, an amino group-containing unsaturated compound, an unsaturated carboxylic acid, an unsaturated carboxylic acid anhydride, a vinyl ester compound, a thiol group-containing unsaturated compound, and derivatives thereof.

[0052] Examples of the hydroxyl group-containing unsaturated compound include hydroxyl group-containing (meth)acrylic acid esters such as hydroxyethyl (meth)acrylate, 2-hydroxypropyl (meth)acrylate, 3-hydroxypropyl (meth)acrylate, 2-hydroxy-3-phenoxy-propyl (meth)acrylate, 3-chloro-2-hydroxypropyl (meth)acrylate, glycerin mono(meth)acrylate, pentaerythritol mono(meth)acrylate, trimethylolpropane mono(meth)acrylate, tetramethylol ethane mono(meth)acrylate, butanediol mono(meth)acrylate, polyethylene glycol mono(meth)acrylate, 2-(6-hydroxyhexanoyloxy)ethyl (meth)acrylate, and 2-(meth)acryloyloxyethyl acid phosphate; 10-undecen-1-ol, 1-octen-3-ol, 2-methanol norbornene, hydroxystyrene, N-methylol (meth)acrylamide, glycerin monoallyl ether, allyl alcohol, allyloxyethanol, 2-butene-1,4-diol, and glycerin monoalcohol.

[0053] Examples of the amino group-containing unsaturated compound include vinyl monomers having at least one kind of amino group or substituted amino group represented by -NHR 1 Examples of the R 1 include a hydrogen atom, an alkyl group having 1 to 12 carbon atoms, preferably 1 to 8 carbon atoms, or a cycloalkyl group having 4 to 12 carbon atoms, preferably 6 to 9 carbon atoms. Note that the R 1 also includes a group in which a part of the alkyl group and cycloalkyl group is substituted with a substituent.

[0054] Examples of the amino group-containing unsaturated compound include aminomethyl (meth)acrylate, aminoethyl (meth)acrylate, aminopropyl (meth)acrylate, propylaminoethyl (meth)acrylate, dimethylaminoethyl (meth)acrylate, phenylaminomethyl (meth)acrylate, cyclohexylaminoethyl (meth)acrylate, N-vinyldiethylamine, N-acetylvinylamine, (meth)acrylamide, N-methyl (meth)acrylamide, N,N-dimethyl (meth)acrylamide, N,N-dimethylaminopropyl (meth)acrylamide, p-aminohexyl succinimide, and 2-aminoethyl succinimide.

[0055] Examples of the unsaturated carboxylic acid include acrylic acid, methacrylic acid, maleic acid, fumaric acid, tetrahydrophthalic acid, itaconic acid, citraconic acid, crotonic acid, isocrotonic acid, norbornenedicarboxylic acid, and bicyclo[2.2.1]hept-2-ene-5,6-dicarboxylic acid.

[0056] Examples of the unsaturated carboxylic anhydride include maleic anhydride, itaconic anhydride, citraconic anhydride, tetrahydrophthalic anhydride, and bicyclo[2.2.1]hept-2-ene-5,6-dicarboxylic anhydride.

[0057] Examples of the vinyl ester compound include vinyl acetate, vinyl propionate, n-butyrate vinyl, isobutyrate vinyl, pivalate vinyl, caproate vinyl, versatate vinyl, laurate vinyl, stearate vinyl, benzoate vinyl, salicylate vinyl, and cyclohexanecarboxylate vinyl.

[0058] Examples of the thiol group-containing unsaturated compound include thiophenol derivatives such as allyl mercaptan, 2-vinylbenzyl mercaptan, 3-vinylbenzyl mercaptan, 4-vinylbenzyl mercaptan, and vinylthiophenol.

[0059] Examples of the derivative include maleinyl chloride, maleinyl imide, dimethyl maleate, monomethyl maleate, diethyl maleate, diethyl fumarate, dimethyl itaconate, diethyl citraconate, dimethyl tetrahydrophthalate, and dimethyl bicyclo[2.2.1]hept-2-ene-5,6-dicarboxylate.

[0060] As the monomer having the functional group, when forming the adhesive layer, it can react efficiently, enhance the affinity for the base material, surface layer, and conductive material, and further improve the adhesive strength between the adhesive layer and the adherend. Also, it can improve the chemical resistance and electrolyte resistance of the obtained adhesive layer. From these aspects, unsaturated carboxylic acids and unsaturated carboxylic anhydrides are preferred, unsaturated carboxylic anhydrides are more preferred, and maleic anhydride is even more preferred.

[0061] The Mw of the modified polymer (b) measured by GPC and converted to standard polystyrene is preferably 1×10 4 or more, more preferably 2×10 4 or more, particularly preferably 3×10 4 or more, and preferably 1×10 7 or less, more preferably 1×10 6 or less, particularly preferably 5×10 5 or less.

[0062] When the Mw of the modified polymer (b) satisfies the lower limit requirement, the adhesive strength is sufficiently high, and an adhesive layer excellent in the adhesive strength with the adherend can be easily obtained. When the upper limit requirement is satisfied, a modified polymer (b) having good solubility in a solvent and being less likely to solidify and precipitate can be obtained. In particular, when the Mw of the modified polymer (b) is 5×10 5 or less, an adhesive layer having even better adhesive strength with the adherend can be obtained.

[0063] The Mw / Mn of the modified polymer (b) is preferably 1 or more, more preferably 1.5 or more, preferably 3 or less, and more preferably 2.5 or less. When Mw / Mn satisfies the above lower limit requirement, a modified polymer (b) with good solubility in a solvent and difficult to solidify and precipitate can be obtained. When it satisfies the above upper limit requirement, a sufficient high adhesive strength can be achieved, and an adhesive layer excellent in the adhesive strength with an adherend can be easily obtained.

[0064] The Tm of the modified polymer (b) is preferably less than 120 °C, more preferably less than 100 °C, still more preferably 90 °C or lower, particularly preferably 87 °C or lower, and is preferably 40 °C or higher, more preferably 50 °C or higher. When the Tm of the modified polymer (b) satisfies the above upper limit requirement, even if an adhesive layer is formed from this adhesive under low-temperature curing conditions, a decrease in adhesive strength can be suppressed. When it satisfies the above lower limit requirement, an adhesive layer excellent in adhesive strength and durability can be obtained. The modified polymer (b) having the above Tm can be obtained, for example, by appropriately adjusting the content ratio of the structural units derived from α-olefins having 2 to 3 carbon atoms in the modified polymer (b).

[0065] The ΔH of the modified polymer (b) is preferably 0 J / g or more, more preferably 3 J / g or more, particularly preferably 5 J / g or more, and is preferably 50 J / g or less, more preferably 40 J / g or less, particularly preferably 35 J / g or less. When the ΔH of the modified polymer (b) satisfies the above upper limit requirement, even if an adhesive layer is formed from this adhesive under low-temperature curing conditions, an adhesive layer excellent in adhesive strength can be obtained. When it satisfies the above lower limit requirement, an adhesive layer excellent in adhesive strength can be easily obtained. The modified polymer (b) having the above ΔH can be obtained, for example, by appropriately adjusting the content ratio of the structural units derived from α-olefins having 2 to 3 carbon atoms in the modified polymer (b).

[0066] The half-crystallization time of the modified polymer (b) at 50 °C is preferably 100 seconds or more, more preferably 150 seconds or more, still more preferably 200 seconds or more. Further, the half-crystallization time includes cases where crystallization does not substantially occur or the value of the half-crystallization time is too large to be determined, that is, the half-crystallization time is infinite. When the half-crystallization time of the modified polymer (b) satisfies the above lower limit requirement, the modified polymer (b) can react with the following curing agent while infiltrating into the unevenness on the surface of the adherend or after infiltration, and the adhesion strength of the resulting adhesive layer can be further improved by the anchor effect. The half-crystallization time can be determined by isothermal crystallization measurement using a differential scanning calorimeter.

[0067] The kinematic viscosity of the modified polymer (b) at 40 °C preferably exceeds 500,000 cSt. Here, when the kinematic viscosity exceeds 500,000 cSt, cases where the fluidity is low and the kinematic viscosity cannot be measured are included. In the present invention, the kinematic viscosity at 40 °C is measured based on ASTM D 445.

[0068] The content ratio (modification amount) of the structural unit derived from the monomer having a functional group in the modified polymer (b) is preferably 0.1% by mass or more, more preferably 0.5% by mass or more, based on 100% by mass of the modified polymer (b), and is preferably 15% by mass or less, more preferably 10% by mass or less, still more preferably 5% by mass or less, particularly preferably 4% by mass or less, and still more preferably 2% by mass or less. When the modification amount is within the above range, when forming the adhesive layer, the modified polymer (b) reacts efficiently, enhances the affinity of the modified polymer (b) for the adherend, and can further improve the adhesion strength between the adhesive layer and the adherend, and can also improve the chemical resistance of the resulting adhesive layer.

[0069] 〈Styrenic elastomer〉 There are no particular restrictions on the type and manufacturing method of the styrenic elastomer. For example, copolymers containing structural units derived from monovinyl aromatic hydrocarbons such as styrene can be mentioned. The styrenic elastomer may be a modified styrenic elastomer modified with a monomer having a functional group. The modification can be carried out by a conventionally known method.

[0070] Examples of the styrenic elastomer include copolymers having a monovinyl-substituted aromatic hydrocarbon (styrenic aromatic hydrocarbon) as a copolymerization component. Specific examples include styrene-ethylene-butylene-styrene block copolymer (SEBS), styrene-ethylene-propylene-styrene block copolymer (SEPS), styrene-butylene-butadiene-styrene block copolymer (SBBS), styrene-butadiene rubber (SBR), styrene-isoprene rubber (SIR), styrene-ethylene copolymer, styrene-butadiene-styrene copolymer (SBS), styrene-isoprene-styrene copolymer (SIS), poly(α-methylstyrene)-polybutadiene-poly(α-methylstyrene) (α-MeSBα-MeS), poly(α-methylstyrene)-polyisoprene-poly(α-methylstyrene) (α-MeSIα-MeS). Furthermore, copolymers in which the conjugated diene moiety constituting these copolymers, specifically, the structural units derived from butadiene or isoprene are hydrogenated can be mentioned. Among these, SEBS and SEPS are preferred.

[0071] Examples of the monomer having a functional group for modifying the styrenic elastomer include the monomers having a functional group described in the column of the modified polymer (b). Among these, unsaturated carboxylic acids or unsaturated carboxylic acid anhydrides are preferred, unsaturated carboxylic acid anhydrides are more preferred, and maleic anhydride is even more preferred.

[0072] In the modified styrene-based elastomer, the content ratio (modification amount) of the structural unit derived from the monomer having a functional group is preferably 0.1% by mass or more, more preferably 0.5% by mass or more, based on 100% by mass of the modified styrene-based elastomer, and is preferably 15% by mass or less, more preferably 10% by mass or less, still more preferably 5% by mass or less, particularly preferably 4% by mass or less, and still more preferably 3% by mass or less.

[0073] Commercially available products can also be used as the modified styrene-based elastomer. Specific examples of the commercially available products include Dynaron 8630P (manufactured by JSR (example)) and Tough Tech M1913 (manufactured by Asahi Kasei Corporation).

[0074] <Other polar components> This adhesive may further contain other polar components for the purpose of improving the adhesion to a substrate, surface layer, or conductive material, and improving the low-temperature curability. The other polar components are polar components other than the modified thermoplastic elastomer modified with the monomer having the above-described functional group. When this adhesive contains other polar components, each of the other polar components contained in this adhesive may be one kind or two or more kinds.

[0075] When a modified thermoplastic elastomer (e.g., modified polymer (b), modified styrene-based elastomer) is used as the thermoplastic elastomer, it is preferable to use at least one curing agent selected from isocyanate compounds, epoxy compounds, and oxazoline compounds as the polar component.

[0076] 〔Isocyanate compound〕 Examples of the isocyanate compound include polyisocyanate monomers and polyisocyanate modified products.

[0077] Examples of the polyisocyanate monomer include aromatic polyisocyanates, araliphatic polyisocyanates, and aliphatic polyisocyanates.

[0078] Examples of aromatic polyisocyanates include aromatic diisocyanates such as tolylene diisocyanate (e.g., 2,4- or 2,6-tolylene diisocyanate or mixtures thereof) (TDI), phenylene diisocyanate (e.g., m- or p-phenylene diisocyanate or mixtures thereof), 4,4'-diphenyl diisocyanate, 1,5-naphthalene diisocyanate (NDI), diphenylmethane diisocyanate (e.g., 4,4'-, 2,4'- or 2,2'-diphenylmethane diisocyanate or mixtures thereof) (MDI), 4,4'-toluidine diisocyanate (TODI), 4,4'-diphenyl ether diisocyanate, and the like.

[0079] Examples of aromatic aliphatic polyisocyanates include aromatic aliphatic diisocyanates such as xylylene diisocyanate (e.g., 1,3- or 1,4-xylylene diisocyanate or mixtures thereof) (XDI), tetramethylxylylene diisocyanate (e.g., 1,3- or 1,4-tetramethylxylylene diisocyanate or mixtures thereof) (TMXDI), ω,ω'-diisocyanate-1,4-diethylbenzene, and the like.

[0080] Examples of aliphatic polyisocyanates include aliphatic diisocyanates such as trimethylene diisocyanate, 1,2-propylene diisocyanate, butylene diisocyanate (e.g., 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, and the like.

[0081] In addition, the aliphatic polyisocyanate includes an alicyclic polyisocyanate. Examples of the alicyclic polyisocyanate include 1,3-cyclopentane diisocyanate, 1,3-cyclopentene diisocyanate, cyclohexane diisocyanate (e.g., 1,4-cyclohexane diisocyanate, 1,3-cyclohexane diisocyanate), 3-isocyanatomethyl-3,5,5-trimethylcyclohexyl isocyanate (isophorone diisocyanate) (IPDI), methylene bis(cyclohexyl isocyanate) (e.g., 4,4'-, 2,4'- or 2,2'-methylene bis(cyclohexyl isocyanate), their Trans,Trans-form, Trans,Cis-form, Cis,Cis-form, or a mixture thereof) (H12MDI), methylcyclohexane diisocyanate (e.g., methyl-2,4-cyclohexane diisocyanate, methyl-2,6-cyclohexane diisocyanate), norbornane diisocyanate (including various isomers or a mixture thereof) (NBDI), bis(isocyanatomethyl)cyclohexane (e.g., 1,3- or 1,4-bis(isocyanatomethyl)cyclohexane or a mixture thereof) (H6XDI), and other alicyclic diisocyanates.

[0082] As the polyisocyanate monomer, aliphatic polyisocyanate and alicyclic polyisocyanate are preferred, PDI, H6XDI, and HDI are more preferred, and HDI is even more preferred.

[0083] Examples of the polyisocyanate modified product include compounds having an average functionality of more than 2. For example, multimers of the polyisocyanate monomer (e.g., dimers, trimers (e.g., isocyanurate modified product, iminooxadiazinedione modified product), pentamers, heptamers), allophanate modified products (e.g., allophanate modified products produced by the reaction of the polyisocyanate monomer with a monool (e.g., a monool having 1 to 20 carbon atoms such as octadecanol)), polyol modified products (e.g., polyol modified products (alcohol adducts) produced by the reaction of the polyisocyanate monomer with a low molecular weight polyol (a compound having two or more hydroxyl groups and a number average molecular weight of 40 or more and less than 400, e.g., a trivalent alcohol such as trimethylolpropane)), biuret modified products (e.g., biuret modified products produced by the reaction of the polyisocyanate monomer with water or amines), urea modified products (e.g., urea modified products produced by the reaction of the polyisocyanate monomer with a diamine), oxadiazinetrione modified products (e.g., oxadiazinetrione produced by the reaction of the polyisocyanate monomer with carbon dioxide gas), carbodiimide modified products (e.g., carbodiimide modified products produced by the decarboxylation condensation reaction of the polyisocyanate monomer), uretdione modified products, and uretonimine modified products.

[0084] Furthermore, examples of the polyisocyanate modified product also include polymethylene polyphenyl polyisocyanate (crude MDI, polymeric MDI), etc.

[0085] As the polyisocyanate modified product, multimers and polyol modified products of the polyisocyanate monomer are preferred, and trimers of the polyisocyanate monomer are more preferred.

[0086] These polyisocyanate modified products may be prepared by known methods or commercially available products may be used. Examples of the commercially available products include Takenate D-170N (trimer modified product (trimer) of 1,6-hexamethylene diisocyanate, manufactured by Mitsui Chemicals, Inc.), Takenate D-120N (polyol modified product of H6XDI, manufactured by Mitsui Chemicals, Inc.).

[0087] [Epoxy compound] The epoxy compound is preferably a crosslinkable compound having two or more epoxy groups in one molecule. Examples of such epoxy compounds include bisphenol type epoxy resins such as bisphenol A type epoxy resin (different from hydrogenated bisphenol A type epoxy resin), bisphenol F type epoxy resin; hydrogenated bisphenol type epoxy resin; novolak type epoxy resin; biphenyl type epoxy resin; stilbene type epoxy resin; hydroquinone type epoxy resin; naphthalene skeleton type epoxy resin; tetraphenylol ethane type epoxy resin; trishydroxyphenylmethane type epoxy resin; dicyclopentadiene phenol type epoxy resin; alicyclic epoxy compounds such as 3’,4’-epoxycyclohexylmethyl-3,4-epoxycyclohexanecarboxylate, 1,2-epoxy-4-(2-oxiranyl)cyclohexane adduct of 2,2-bis(hydroxymethyl)-1-butanol; polyglycidyl esters of polybasic acids such as diglycidyl ester of hexahydrophthalic anhydride; glycidyl ethers such as sorbitol polyglycidyl ether, sorbitan polyglycidyl ether, pentaerythritol polyglycidyl ether, trimethylolpropane polyglycidyl ether, polypropylene glycol diglycidyl ether, diglycerol polyglycidyl ether, glycerol polyglycidyl ether, hexanediol diglycidyl ether, hydrogenated bisphenol A diglycidyl ether and cyclohexanedimethanol diglycidyl ether; diene polymer type epoxy resins such as polybutadiene or polyisoprene; glycidylamine type epoxy resins such as tetraglycidyldiaminodiphenylmethane, tetraglycidylbisaminomethylcyclohexane, diglycidylaniline, tetraglycidylmethaxylylenediamine; heterocyclic ring-containing epoxy resins such as triazine or hydantoin.

[0088] Among the epoxy compounds, bisphenol A type liquid epoxy resin, alicyclic epoxy compound, and trimethylolpropane polyglycidyl ether are preferable in terms of having more excellent adhesive strength, particularly in terms of being able to form an adhesive layer that can adhere to the adherend with higher strength.

[0089] The bisphenol A type liquid epoxy resin is not particularly limited as long as it is a resin that is liquid at normal temperature (25°C), and commercially available products may be used. Examples of such commercially available products include EPICLON 840, 840-S, 850, 850-S, EXA-850CRP, 850-LC (manufactured by DIC Corporation), jER828EL, 827 (manufactured by Mitsubishi Chemical Corporation), and Epomic R-140P (manufactured by Mitsui Chemicals, Inc.).

[0090] The alicyclic epoxy compound refers to a compound having at least one epoxycycloalkyl group or epoxycycloalkenyl group in the molecule, or a compound having at least one group in which at least one epoxy group is bonded to the alicyclic ring by a single bond in the molecule.

[0091] Examples of the alicyclic epoxy compound include 3,4-epoxycyclohexenylmethyl-3',4'-epoxycyclohexenecarboxylate, 3',4'-epoxycyclohexylmethyl-3,4-epoxycyclohexanecarboxylate, 3,4-epoxycyclohexyloctyl-3,4-epoxycyclohexanecarboxylate, 2-(3,4-epoxycyclohexyl-5,5-spiro-3,4-epoxy)cyclohexane-m-dioxane, bis(3,4-epoxycyclohexylmethyl)adipate, vinylcyclohexene dioxide, bis(3,4-epoxy-6-methylcyclohexylmethyl)adipate, 3,4-epoxy-6-methylcyclohexyl-3,4-epoxy-6-methylcyclohexanecarboxylate, methylenebis(3,4-epoxycyclohexane), dicyclopentadiene diepoxide, ethylene glycol bis(3,4-epoxycyclohexylmethyl)ether, ethylene bis(3,4-epoxycyclohexanecarboxylate), 1,2,8,9-diepoxylimonene, 1,2-epoxy-4-(2-oxiranyl)cyclohexane adduct of 2,2-bis(hydroxymethyl)-1-butanol, and the compounds described in JP-A-2008-214555.

[0092] As the alicyclic epoxy compound, commercially available products may be used. Examples of the commercially available products include Celoxide 2021P, EHPE3150, EHPE3150CE, and Epolead GT401 (all manufactured by Daicel Corporation).

[0093] As the alicyclic epoxy compound, 3',4'-epoxycyclohexylmethyl-3,4-epoxycyclohexanecarboxylate is preferable in terms of obtaining an adhesive layer having more excellent adhesive strength.

[0094] Examples of the trimethylolpropane polyglycidyl ether include trimethylolpropane diglycidyl ether, trimethylolpropane triglycidyl ether, and mixtures thereof. As the trimethylolpropane polyglycidyl ether, a commercially available product may be used. Examples of such commercially available products include EX-321L (manufactured by Nagase ChemteX Corporation).

[0095] 〔Oxazoline compound〕 The oxazoline compound is preferably a crosslinkable compound having two or more oxazoline groups in one molecule. Examples of such oxazoline compounds include oxazoline group-containing polymers such as polymers of oxazoline group-containing monomers and copolymers of oxazoline group-containing monomers and other monomers.

[0096] Examples of the oxazoline group-containing monomer include 2-vinyl-2-oxazoline, 2-vinyl-4-methyl-2-oxazoline, 2-vinyl-5-methyl-2-oxazoline, 2-isopropenyl-2-oxazoline, 2-isopropenyl-4-methyl-2-oxazoline, 2-isopropenyl-5-ethyl-2-oxazoline, and 2-isopropenyl-4,4-dimethyl-2-oxazoline. These may be used alone or in combination of two or more.

[0097] Examples of the other monomers include alkyl (meth) acrylates (alkyl group having about 1 to 14 carbon atoms); unsaturated carboxylic acids such as acrylic acid, methacrylic acid, itaconic acid, maleic acid, fumaric acid, crotonic acid, styrenesulfonic acid and its salts (sodium salt, potassium salt, ammonium salt, tertiary amine salt, etc.); unsaturated nitriles such as acrylonitrile and methacrylonitrile; unsaturated amides such as (meth) acrylamide, N-alkyl (meth) acrylamide, N,N-dialkyl (meth) acrylamide (examples of these alkyl groups: methyl group, ethyl group, n-propyl group, isopropyl group, n-butyl group, isobutyl group, t-butyl group, 2-ethylhexyl group, cyclohexyl group); vinyl esters such as vinyl acetate and vinyl propionate; vinyl ethers such as methyl vinyl ether and ethyl vinyl ether; α-olefins such as ethylene and propylene; halogen-containing α,β-unsaturated monomers such as vinyl chloride, vinylidene chloride and vinyl fluoride; and α,β-unsaturated aromatic monomers such as styrene and α-methylstyrene. These may be used alone or in combination of two or more.

[0098] As the oxazoline compound, an oxazoline compound containing 2-isopropenyl-2-oxazoline is preferable from the viewpoint of obtaining an adhesive layer having more excellent adhesive strength. Examples of commercially available products of the oxazoline compound include the "Epocros" series manufactured by Nippon Shokubai Co., Ltd.

[0099] The epoxy equivalent of the epoxy compound and the oxazoline equivalent of the oxazoline compound are preferably 100 g / eq or more, more preferably 125 g / eq or more, and preferably 1,600 g / eq or less, more preferably 500 g / eq or less, from the viewpoint of obtaining an adhesive layer having more excellent adhesive strength, chemical resistance and electrolyte resistance. The equivalent can be measured based on JIS K 7236.

[0100] The compounding amount of the hardener is such that the equivalent of the isocyanate group, epoxy group, and oxazoline group in the hardener / the equivalent of the functional group in the modified thermoplastic elastomer is preferably 0.01 or more, more preferably 0.1 or more, and preferably 50 or less, more preferably 30 or less, still more preferably 20 or less, and particularly preferably 10 or less. It is desirable to compound it so as to satisfy these conditions. When the compounding amount of the hardener is within the above range, an adhesive layer with more excellent adhesive strength and chemical resistance can be obtained.

[0101] 〔Polar components other than the hardener〕 Examples of the polar components other than the hardener include acrylic polymers, polyesters, polyvinyl ethers, and silicone polymers. Among these, acrylic polymers are preferred.

[0102] Specific examples of the acrylic polymer include homopolymers or copolymers of acrylic acid, methacrylic acid, methyl acrylate, ethyl acrylate, propyl acrylate, butyl acrylate, 2-ethylhexyl acrylate, methyl methacrylate, ethyl methacrylate, butyl methacrylate, acrylonitrile, and the like.

[0103] When the adhesive contains an acrylic polymer, the content of the acrylic polymer is preferably 2% by mass or more, more preferably 4% by mass or more, and preferably 60% by mass or less, more preferably 50% by mass or less, based on the total of 100% by mass of the thermoplastic elastomer and the acrylic polymer.

[0104] Examples of the polyester include copolymers of polyhydric alcohols and polybasic acids. Examples of the polyhydric alcohols include ethylene glycol, propylene glycol, and butanediol. Examples of the polybasic acids include terephthalic acid, adipic acid, and maleic acid.

[0105] Examples of the polyvinyl ether include polyvinyl ether and polyvinyl isobutyl ether.

[0106] Examples of the silicone polymer include dimethylpolysiloxane.

[0107] <Hydrocarbon synthetic oil> In addition to the above components, this adhesive may further contain a hydrocarbon synthetic oil in terms of easily obtaining an adhesive layer with high adhesive strength. The hydrocarbon synthetic oil is a component other than the thermoplastic elastomer and other polar components. The hydrocarbon synthetic oil may be used alone or in combination of two or more.

[0108] Examples of the hydrocarbon synthetic oil include polymers of olefins having 2 to 20 carbon atoms. Among them, oligomers obtained by homopolymerizing olefins having 2 to 20 carbon atoms and oligomers obtained by copolymerizing two or more of these olefins are preferable.

[0109] Examples of the olefin having 2 to 20 carbon atoms include ethylene, propylene, 1-butene, 1-octene, 1-decene, and 1-dodecene.

[0110] As the hydrocarbon synthetic oil, an ethylene copolymer containing a structural unit derived from ethylene and a structural unit derived from an α-olefin having 3 to 20 carbon atoms can be preferably used. In this case, the amount of the structural unit derived from ethylene is preferably 30 mol% or more, more preferably 40 mol% or more, preferably 70 mol% or less, and more preferably 60 mol% or less based on 100 mol% in total of the structural unit derived from ethylene and the structural unit derived from an α-olefin having 3 to 20 carbon atoms.

[0111] The hydrocarbon synthetic oil preferably has a kinematic viscosity at 40 °C of 30 cSt or more, more preferably 300 cSt or more, still more preferably 5,000 cSt or more, preferably 500,000 cSt or less, more preferably 400,000 cSt or less, and still more preferably 300,000 cSt or less. Further, the hydrocarbon-based synthetic oil preferably has a kinematic viscosity at 200°C of 10 cSt or more, more preferably 20 cSt or more, still more preferably 30 cSt or more, and preferably 100,000 cSt or less, more preferably 80,000 cSt or less, and even more preferably 60,000 cSt or less. When the kinematic viscosity of the hydrocarbon-based synthetic oil at 40°C or 200°C is within the above range, an adhesive layer with high adhesive strength can be easily obtained.

[0112] When this adhesive contains a hydrocarbon-based synthetic oil, the content of the hydrocarbon-based synthetic oil is preferably 1 part by mass or more and preferably 80 parts by mass or less with respect to a total of 100 parts by mass of the thermoplastic elastomer and other polar components. When the blending amount of the hydrocarbon-based synthetic oil is within the above range, an adhesive layer excellent in strength and adhesive strength can be easily obtained.

[0113] <Preparation method of this adhesive> This adhesive can be prepared by mixing a thermoplastic elastomer and, if necessary, the other polar components and hydrocarbon-based synthetic oil described above.

[0114] In addition, in the adhesive, additives other than the above components may be blended within a range not impairing the effects of the present invention, such as curing catalysts, leveling agents, defoaming agents, antioxidants, heat stabilizers, light stabilizers such as ultraviolet absorbers, plasticizers, surfactants, pigments such as titanium oxide (rutile type), zinc oxide, carbon black, thixotropic agents, thickeners, tackifiers such as rosin resins and terpene resins, surface conditioners, anti-settling agents, weathering agents, pigment dispersants, antistatic agents, fillers, organic or inorganic fine particles, fungicides, and silane coupling agents.

[0115] Furthermore, from the viewpoint of improving processability, the adhesive may be a varnish containing a solvent in addition to the above components. Examples of the solvent include the same solvents as those that can be used in the synthesis of modified thermoplastic elastomers, such as toluene, a mixed solvent of methylcyclohexane / methyl isobutyl ketone, a mixed solvent of methylcyclohexane / methyl ethyl ketone, a mixed solvent of methylcyclohexane / ethyl acetate, a mixed solvent of methylcyclohexane / n-propyl acetate, a mixed solvent of cyclohexane / methyl ethyl ketone, a mixed solvent of cyclohexane / ethyl acetate, and a mixed solvent of cellosolve / cyclohexanone. Note that water can also be used as a dispersion medium.

[0116] It is desirable to formulate the solvent such that the content ratio of the non-volatile matter in 100% by mass of the varnish is, for example, 5% by mass or more, preferably 10% by mass or more, and, for example, 50% by mass or less, preferably 40% by mass or less.

[0117] <Adhesive layer> This adhesive can be applied to an adherend, or the adherend can be immersed in this adhesive and taken out, and if necessary, the adhesive can be dried to form an adhesive layer (hereinafter also referred to as "this adhesive layer") on the adherend. Further, a curing process may be performed. When forming this adhesive layer between two adherends, a so-called dry lamination method in which, after the drying, the adhesive (layer) is brought into contact with the other adherend and then a curing process is performed while applying pressure if necessary is desirable. Since this adhesive layer is obtained from this adhesive, it is excellently balanced in high insulation, low dielectric loss, water resistance, chemical resistance, adhesive strength, and low tackiness.

[0118] The adherend is not particularly limited as long as it is an object to be adhered using this adhesive, and examples thereof include the following base materials, surface layers, and electronic components.

[0119] The method of the coating is not particularly limited. For example, coating methods such as die coating method, flow coating method, spray coating method, bar coating method, gravure coating method, gravure reverse coating method, kiss reverse coating method, microgravure coating method, roll coating method, blade coating method, rod coating method, roll doctor coating method, air knife coating method, comma roll coating method, reverse roll coating method, transfer roll coating method, kiss roll coating method, curtain coating method, printing method can be adopted.

[0120] Examples of the method for drying the present adhesive include leaving it at normal temperature (about 20°C) and normal pressure, drying the present adhesive under reduced pressure, and heating the present adhesive. This heating may be carried out in one step or in two or more steps. The conditions for this heating are not particularly limited as long as the volatile components such as solvents can volatilize. For example, it can be heated at 120°C or lower, preferably 100°C or lower, for example, at 40°C or higher, for example, for 3 seconds or longer, preferably 1 minute or longer, and also, for example, for 1 hour or shorter.

[0121] Examples of the curing step include heating the coating film. This heating may be carried out in one step or in two or more steps. As the conditions for this heating, appropriate conditions are selected. For example, at a low temperature, such as 80°C or lower, preferably 70°C or lower, particularly preferably 60°C or lower, and also, for example, at 40°C or higher, for example, for 1 day or longer, preferably 3 days or longer, and also, for example, for 7 days or shorter (low-temperature curing method); at a high temperature, such as 100°C or higher, preferably 120°C or higher, and also, for example, at 200°C or lower, for example, for 0.1 second or longer, preferably 0.5 second or longer, and also, for example, for 60 seconds or shorter (high-temperature curing method). Among these, the low-temperature curing method is preferred.

[0122] The pressure is, for example, 0.1 MPa or higher, preferably 0.2 MPa or higher, and preferably 2 MPa or lower.

[0123] The thickness of the present adhesive layer may be appropriately selected according to the desired application or the like and is not particularly limited. For example, it is 0.2 μm or more, preferably 1 μm or more, and for example, 100 μm or less, preferably 50 μm or less.

[0124] According to the present adhesive, an adhesive layer having high insulation and low dielectric loss can be obtained without requiring bubbles. Therefore, the present adhesive layer is preferably substantially non-foamed. Substantially non-foamed means the case where the expansion ratio is, for example, 1.01 times or less. When the bubble content in the adhesive layer increases, the relative dielectric constant tends to decrease. However, it is necessary to control the bubble content, and there may be cases where the bubble content varies from place to place in the adhesive layer or the film thickness becomes non-uniform.

[0125] ≪Electronic tag≫ The electronic tag according to an embodiment of the present invention may have the same configuration as a conventional electronic tag as long as it has the present adhesive layer. For example, an electronic tag having at least one electronic member selected from the group consisting of the present adhesive layer, a base material, a circuit line, and an IC chip can be mentioned. Since the electronic tag according to an embodiment of the present invention has the present adhesive layer, it becomes an electronic tag having a long communication distance and operating stably even in a high-humidity environment.

[0126] The electronic tag may have, if necessary, a surface layer for protecting the electronic member, an adhesive layer other than the present adhesive layer, an adhesive layer, a release layer, and the like. These layers and members may each be one layer (one) or two or more layers (two or more). In the case of two or more layers (two or more), they may be the same layer (member) or different layers (members).

[0127] Specifically, as an embodiment of the electronic tag, An electronic tag having at least one electronic member selected from the group consisting of a circuit line and an IC chip on a base material via an adhesive layer (e.g., FIG. 2), On a substrate, at least one electronic component selected from circuit lines and IC chips is arranged, has a surface layer on the side opposite to the substrate of the electronic component, and the electronic component and the surface layer are adhered with an adhesive, an electronic tag (e.g., FIGS. 1 and 3). On a substrate, at least one electronic component selected from circuit lines and IC chips is arranged, has a surface layer on the side opposite to the substrate of the electronic component, and the substrate and the surface layer are adhered with an adhesive, an electronic tag (e.g., FIGS. 1 and 3) may be mentioned.

[0128] Hereinafter, it will be described with reference to FIG. 1. The electronic tag 10 in FIG. 1 has an adhesive layer 2 on a substrate 1 (e.g., an inlet film) having an electronic component including a circuit line 4 and an IC chip 5 (on which the electronic component is mounted), and further has a surface layer 3 thereon. The circuit line 4 and the IC chip 5 in the electronic tag 10 function as a non-contact electronic tag by communicating with an external reader and writer.

[0129] The thickness and formation method of the adhesive layer 2 are not particularly limited, and for example, the thickness and formation method similar to those in the column of the main adhesive layer described above can be mentioned. The adhesive layer 2 may be the main adhesive layer or a layer formed from a conventionally known adhesive, but it is preferably the main adhesive layer that exhibits the above effects.

[0130] As the electronic component, in addition to an IC chip and a circuit line, it may include other constituent members. Examples of such constituent members include capacitors and resistors.

[0131] As the circuit line 4, for example, it may be a coil-shaped circuit in which a wire made of a conductive material is wound into a coil shape, and the laminate of the circuit line 4 and the substrate 1 may be a printed circuit board (printed wiring board) on which a circuit pattern is formed on a substrate. The circuit line 4 may be a so-called antenna. Examples of the circuit line 4 include films such as foil, vapor deposition film, and thin film by sputtering, and it is usually formed of a conductive material. Examples of the conductive material include metals (including alloys) such as gold, silver, copper, nickel, and aluminum, and conductive pastes containing these metal particles and a binder.

[0132] The thickness of the circuit line 4 is not particularly limited. In the case of a metal foil, it is preferably 5 to 50 μm. In the case of a vapor deposition film or a metal film by sputtering, it is preferably 0.01 to 1 μm. In the case of a film obtained from a conductive paste, it is preferably 5 to 30 μm. The width of the circuit line 4 is not particularly limited, but it is preferably 0.01 to 10 mm, more preferably 0.1 to 3 mm.

[0133] In FIG. 1, the IC chip 5 is provided above the circuit line 4, but it may be provided inside or outside the circuit line 4. The IC chip 5 is preferably provided at the tip of the circuit line 4. In order to connect the outermost and innermost rings of the circuit line 4 to the IC chip 5, a jumper wiring portion (not shown) may be used so as not to short-circuit (conduct) with the annular circuit line 4 in the middle of the outermost and innermost rings. The thickness of the IC chip 5 may be appropriately selected according to the application. For example, it is about 50 to 400 μm.

[0134] Examples of the method for forming the circuit line 4 on the base material 1 include a method of forming a circuit line by bonding a metal foil to the base material using an adhesive layer and removing portions other than the circuit by etching the metal foil. Examples of the etching treatment include the same methods as the conventionally known etching treatments. By this method, for example, an electronic tag having a structure as shown in FIG. 2 near the electronic member can be obtained. The adhesive layer 6 in FIG. 2 may be the present adhesive layer or a layer formed of a conventionally known adhesive, but the present adhesive layer that exhibits the above effects is preferred. As a method of forming the circuit line 4 on the base material 1, there is also a method of printing, applying, etc. a conductive paste in a desired circuit line shape on the base material or on the adhesive layer of the base material having an adhesive layer.

[0135] Examples of the material of the base material 1 include polyester resins such as polyethylene terephthalate (PET), polybutylene terephthalate (PBT), and polyethylene terephthalate / isophthalate copolymer; polyolefin resins such as polyethylene (PE), polypropylene (PP), and polymethylpentene; polyfluoroethylene resins such as polyvinyl fluoride, polyvinylidene fluoride, poly (4-fluoroethylene), and ethylene / (4-fluoroethylene) copolymer; polyamide resins such as 6-nylon and 6,6-nylon; vinyl resins such as polyvinyl chloride, vinyl chloride / vinyl acetate copolymer, ethylene / vinyl acetate copolymer, ethylene / vinyl alcohol copolymer, polyvinyl alcohol, and vinylon; cellulose resins such as triacetate cellulose and cellophane; acrylic resins such as polymethyl methacrylate, polyethyl methacrylate, polyethyl acrylate, and polybutyl acrylate; and synthetic resins such as polystyrene, polycarbonate, polyarylate, and polyimide are preferred.

[0136] The base material 1 is preferably a base material sheet in a sheet shape (including plate shape, film shape, etc.). In this case, the thickness of the base material sheet is not particularly limited, but is, for example, 10 to 300 μm.

[0137] The surface layer 3 is preferably a layer that covers the electronic member, and more preferably a layer that protects the electronic member and maintains the shape of the electronic tag. As the surface layer 3, a layer made of the same material as the material constituting the base material 1 can be used. Paper can also be used. Printing can also be performed on the surface of the surface layer 3 opposite to the adhesive layer 2. The thickness of the surface layer 3 is not particularly limited, but is, for example, about 30 to 500 μm.

[0138] On the side of the base material 1 opposite to the electronic component, there may be a support or a release layer 8. In this case, the support 8 may exist via the adhesive layer 7, or the release layer 8 may exist via the pressure-sensitive adhesive layer 7 (Fig. 3). Note that the base material 1, the adhesive layer 2, the surface layer 3, the circuit line 4, and the IC chip 5 in Fig. 3 are the same as those in Fig. 1.

[0139] As the support 8, a layer made of the same material as the material constituting the base material 1 can be used. Paper can also be used. The adhesive layer 7 may be this adhesive layer or a layer formed from a conventionally known adhesive, but it is preferably this adhesive layer that exhibits the above effects.

[0140] Examples of the pressure-sensitive adhesive layer 7 include a layer for attaching the electronic tag to a desired article when using the electronic tag. As the pressure-sensitive adhesive layer 7, a conventionally known pressure-sensitive adhesive layer can be used. Also, a layer obtained from this adhesive as in Examples 6 and 7 below can be used. The release layer 8 is a layer for protecting the pressure-sensitive adhesive layer 7 during storage of the electronic tag, etc., in order to prevent foreign matter from adhering to the pressure-sensitive adhesive layer 7 and reducing the adhesive strength. When using the electronic tag, the release layer 8 is peeled off to expose the pressure-sensitive adhesive layer 7 for use. As the release layer 8, a layer made of the same material as the material constituting the base material 1 can be used. Paper can also be used.

Examples

[0141] Hereinafter, the present invention will be described in more detail based on examples, but the present invention is not limited to these examples.

[0142] <Content ratio of structural units derived from propylene, ethylene, and 1-butene> The content ratio of the structural units derived from each of propylene, ethylene, and 1-butene in the polymer obtained in the following production example was 13 determined using C-NMR.

[0143] <Melting point (Tm) and heat of fusion (ΔH)> Using a differential scanning calorimeter (manufactured by TA Instruments; DSC-Q1000), the melting point (Tm) and heat of fusion (ΔH) of the polymer obtained in the following Production Example were determined. The specific method is as described above.

[0144] <Weight-average molecular weight (Mw)> The weight-average molecular weight (Mw) was measured under the following conditions using a gel permeation chromatograph (manufactured by Shimadzu Corporation; LC-10 series). From the obtained measurement results, the Mw of the polymer obtained in the following Production Example was calculated using a calibration curve prepared with monodisperse standard polystyrene.

[0145] · Detector: manufactured by Shimadzu Corporation; C-R4A · Columns: TSKG 6000H - TSKG 4000H - TSKG 3000H - TSKG 2000H (all manufactured by Tosoh Corporation) · Mobile phase: tetrahydrofuran · Temperature: 40°C · Flow rate: 0.8 mL / min

[0146] <Degree of modification> The content ratio (degree of modification) of maleic anhydride in the polymer obtained in the following Production Example was 1 determined from measurement by 1H-NMR. The specific method is as follows.

[0147] The degree of modification was measured using an ECX400 type nuclear magnetic resonance apparatus (manufactured by JEOL Ltd.), with deuterated orthodichlorobenzene as the solvent, a sample concentration of 20 mg / 0.6 mL, a measurement temperature of 120°C, and the observed nucleus being 1 1H (400 MHz), the sequence being a single pulse, the pulse width being 5.12 μs (45° pulse), the repetition time being 7.0 s, and the number of integrations being 500 or more. The reference chemical shift is set to 0 ppm for the peak derived from the hydrogen of tetramethylsilane. However, for example, similar results can also be obtained by setting the peak derived from the residual hydrogen of deuterated orthodichlorobenzene to 7.10 ppm. Derived from maleic anhydride 1 Peaks such as H can be assigned by conventional methods.

[0148] <Kinematic viscosity at 40 °C or 200 °C> The kinematic viscosity at 40 °C or 200 °C of the polymer obtained in the following production example was measured based on ASTM D 445.

[0149] [Production Example 1-1]: Synthesis of thermoplastic elastomer (A-1) 900 ml of hexane and 90 g of 1-butene were charged into a 2-liter autoclave sufficiently purged with nitrogen. 1 millimole of triisobutylaluminum was added, and the temperature was raised to 70 °C. Then, propylene was supplied to make the total pressure 7 kg / cm 2 G. 0.30 millimole of methylaluminoxane and 0.001 millimole of rac-dimethylsilylene-bis{1-(2-methyl-4-phenylindenyl)}zirconium dichloride in terms of Zr atom were added. Propylene was continuously supplied while maintaining the total pressure at 7 kg / cm 2 G for 30 minutes for polymerization. After polymerization, degassing was performed, and the polymer was recovered in a large amount of methanol and dried under reduced pressure at 110 °C for 12 hours. The melting point of the obtained propylene / 1-butene copolymer (hereinafter also referred to as "thermoplastic elastomer (A-1)") was 78.3 °C, the heat of fusion was 29.2 J / g, Mw was 330,000, and the propylene content was 67.2 mol%.

[0150] [Production Example 1-2]: Synthesis of thermoplastic elastomer (A-2) 900 ml of hexane and 80 g of 1-butene were charged into a 2-liter autoclave sufficiently purged with nitrogen. 1 millimole of triisobutylaluminum was added, and the temperature was raised to 70 °C. Then, propylene was supplied to make the total pressure 7 kg / cm 2 G. 0.30 millimole of methylaluminoxane and 0.001 millimole of rac-dimethylsilylene-bis{1-(2-methyl-4-phenylindenyl)}zirconium dichloride in terms of Zr atom were added. Propylene was continuously supplied while maintaining the total pressure at 7 kg / cm 2Polymerization was carried out for 30 minutes while maintaining at G. After polymerization, degassing was performed and the polymer was recovered in a large amount of methanol, and dried under reduced pressure at 110 °C for 12 hours. The melting point of the obtained propylene / 1-butene copolymer (hereinafter also referred to as "thermoplastic elastomer (A-2)") was 89.2 °C, the heat of fusion was 31.5 J / g, Mw was 330,000, and the propylene content was 73.5 mol%.

[0151] [Production Example 1-3]: Synthesis of Thermoplastic Elastomer (A-3) 3 kg of the thermoplastic elastomer (A-2) was added to 10 L of toluene, and the temperature was raised to 145 °C under a nitrogen atmosphere to dissolve the elastomer (A-2) in toluene. Thereto, 382 g of maleic anhydride and 175 g of di-tert-butyl peroxide were supplied over 4 hours with stirring, and then stirring was continued at 145 °C for 2 hours. After cooling, a large amount of acetone was added to precipitate the modified copolymer, and the precipitate was filtered, washed with acetone, and then dried under vacuum. The melting point of the obtained maleic anhydride-modified propylene / 1-butene copolymer (hereinafter also referred to as "thermoplastic elastomer (A-3)") was 85.9 °C, the heat of fusion was 29.9 J / g, Mw was 110,000, and the modification amount of maleic anhydride was 1 mass% with respect to 100 mass% of the elastomer (A-3).

[0152] [Production Example 1-4]: Synthesis of Thermoplastic Elastomer (A-4) 1.5 kg of the thermoplastic elastomer (A-1) and 1.5 kg of Septon 2002 (SEPS, manufactured by Kuraray Co., Ltd.) were added to 10 L of toluene, and the temperature was raised to 145 °C under a nitrogen atmosphere to dissolve these copolymers in toluene. Thereto, 382 g of maleic anhydride and 175 g of di-tert-butyl peroxide were supplied over 4 hours with stirring, and then stirring was continued at 145 °C for 2 hours. After cooling, a large amount of acetone was added to precipitate the modified copolymer, and the precipitate was filtered, washed with acetone, and then dried under vacuum. The melting point of the obtained maleic anhydride-modified propylene / 1-butene copolymer-SEPS mixture (hereinafter also referred to as "thermoplastic elastomer (A-4)") was 75.6 °C, the heat of fusion was 14.7 J / g, Mw was 98,000, and the modification amount of maleic anhydride was 1% by mass based on 100% by mass of the elastomer (A-4). It is considered that the thermoplastic elastomer (A-4) contains approximately equal amounts of maleic anhydride-modified propylene / 1-butene copolymer and maleic anhydride-modified SEPS.

[0153] [Production Example 1-5]: Synthesis of Thermoplastic Elastomer (A-5) 3 kg of Kraton G1652M (SEBS, manufactured by Kraton) was added to 10 L of toluene, and the temperature was raised to 145 °C under a nitrogen atmosphere to dissolve the copolymer in toluene. Thereto, 382 g of maleic anhydride and 175 g of di-tert-butyl peroxide were supplied over 4 hours with stirring, and then stirring was continued at 145 °C for 2 hours. After cooling, a large amount of acetone was added to precipitate the modified copolymer, and the precipitate was filtered, washed with acetone, and then dried under vacuum. The melting point and heat of fusion of the obtained maleic anhydride-modified SEBS (hereinafter also referred to as "thermoplastic elastomer (A-5)") were not observed, Mw was 100,000, and the modification amount of maleic anhydride was 2% by mass based on 100% by mass of the elastomer (A-5).

[0154] [Production Example 2-1]: Synthesis of Hydrocarbon-Based Synthetic Oil (B-1) 1 liter of dehydrated and purified hexane was added to a continuously polymerizing reactor equipped with a stirring blade that had been sufficiently purged with nitrogen, and a hexane solution of ethylaluminum sesquichloride (Al(C2H5) 1.5 ·Cl 1.5 ) adjusted to 96 mmol / L was continuously supplied at a rate of 500 ml / h for 1 hour. Then, as a catalyst, a hexane solution of VO(OC2H5)Cl2 adjusted to 16 mmol / L and hexane were continuously supplied at 500 ml / h each. At this time, the polymerization solution was continuously withdrawn from the upper part of the reactor so that the polymerization solution in the reactor always remained at 1 liter. Next, ethylene gas was supplied at a rate of 47 L / h, propylene gas at a rate of 47 L / h, and hydrogen gas at a rate of 20 L / h using a bubbling tube. The copolymerization reaction was carried out at 35 °C by circulating a refrigerant through a jacket attached outside the reactor. The resulting polymerization solution was deashed with hydrochloric acid, then poured into a large amount of methanol to precipitate a precipitate, and the precipitate was dried under reduced pressure at 130 °C for 24 hours. The obtained ethylene / propylene copolymer (hereinafter also referred to as "hydrocarbon-based synthetic oil (B-1)") had an ethylene content of 55.9 mol%, Mw of 14,000, a kinematic viscosity at 40 °C of 37,500 cSt, and a kinematic viscosity at 200 °C of 132 cSt.

[0155] [Example 1] 100 g of thermoplastic elastomer (A-4) was dissolved by heating in 400 g of a mixed solvent of methylcyclohexane / ethyl acetate = 75 / 25 (mass ratio) to prepare adhesive A.

[0156] [Example 2] 80 g of thermoplastic elastomer (A-3) and 20 g of hydrocarbon-based synthetic oil (B-1) were dissolved by heating in 400 g of a mixed solvent of methylcyclohexane / ethyl acetate = 80 / 20 (mass ratio). After cooling, 5 g of Stabio D-370N (isocyanate curing agent, manufactured by Mitsui Chemicals, Inc.) was added to prepare adhesive B.

[0157] [Example 3] Adhesive C was prepared in the same manner as in Example 2, except that 5 g of Celloxide 2021P (epoxy curing agent, manufactured by Daicel Corporation) was used instead of 5 g of Stabio D-370N in Example 2.

[0158] [Example 4] Adhesive D was prepared in the same manner as in Example 2, except that Stabio D-370N was not used in Example 2.

[0159] [Example 5] Clayton G1652, 63 g, was dissolved by heating in 152 g of a mixed solvent of methylcyclohexane / n-propyl acetate = 4 / 15 (mass ratio). Then, a monomer solution prepared by uniformly mixing 46.3 g of methyl methacrylate, 2.5 g of n-butyl acrylate, 11.7 g of n-butyl methacrylate, 2.5 g of methacrylic acid, 0.76 g of Perbutyl O (manufactured by NOF Corporation), and 107 g of n-propyl acetate was added dropwise thereto over 2 hours and polymerized at 95°C. Finally, 114 g of n-propyl acetate was added to prepare Adhesive E.

[0160] [Example 6] 100 g of thermoplastic elastomer (A-5) was dissolved by heating in 400 g of a mixed solvent of methylcyclohexane / methyl ethyl ketone = 6 / 4 (mass ratio) to prepare Adhesive F.

[0161] [Example 7] 100 g of thermoplastic elastomer (A-5) was dissolved by heating in 400 g of a mixed solvent of methylcyclohexane / methyl ethyl ketone = 6 / 4 (mass ratio). After cooling, 5 g of Celloxide 2021P was blended to prepare Adhesive G.

[0162] [Comparative Example 1] 150 g of Takelac A-969V (manufactured by Mitsui Chemicals, Inc.) was diluted with 350 g of ethyl acetate, and 50 g of Takenate A-5 (manufactured by Mitsui Chemicals, Inc.) was blended therein to prepare Adhesive H (urethane adhesive).

[0163] [Measurement of Relative Permittivity and Dielectric Dissipation Factor] On a 100-μm-thick release PET, the adhesives of Examples 1 to 7 and Comparative Example 1 were each coated so that the dry film thickness became about 60 μm, dried at 100 °C for 3 minutes, and cured at 60 °C for 3 days to form a coating film on the release PET. After measuring the film thickness of the coating film obtained with a film thickness gauge, tin foil was placed on the coating film from which the release PET was peeled off, and using a 4284A Precision LCR Meter (manufactured by Keysight Technologies), the relative permittivity and dielectric tangent of the coating film were measured at measurement frequencies of 1 kHz, 10 kHz, 100 kHz, and 1 MHz. Also, for a measurement frequency of 10 GHz, the coating film was formed into a strip shape, and the relative permittivity and dielectric tangent were measured by the cavity resonator method (Vector Network Analyzer HP8510B (manufactured by Keysight Technologies, Inc.)) in accordance with JIS R 1641:2007. The results are shown in Table 1. Also, the absolute value of the difference between the relative permittivity measured at a frequency of 1 kHz and the relative permittivity measured at a frequency of 10 GHz was defined as Requirement (3), and the difference between the maximum value and the minimum value of the dielectric tangent measured at frequencies of 1 kHz, 10 kHz, 100 kHz, 1 MHz, and 10 GHz was defined as Requirement (4) and shown in Table 1.

[0164] <Measurement of Al / PET Peel Strength> On an Al foil (thickness: 30 μm), the adhesives of Examples 1 to 7 and Comparative Example 1 were each coated and dried at 100 °C for 1 minute to form an Al foil with a coating film having a dry film thickness of about 3 μm. A PET film (manufactured by Toray Industries, Inc., thickness: 100 μm) was placed on the coating film of the Al foil with the coating film, and thermocompression bonding was performed on the PET film under the conditions of 180 °C, 0.3 MPa, and 3 seconds, and further cured at 60 °C for 3 days. The obtained laminate was cut out into a size of 15 mm in width to prepare a test piece, and for this test piece, a 180° peel test was carried out at a crosshead speed of 50 mm / min using a universal tensile measuring device (manufactured by Intesco Co., Ltd., model 210), and the peel strength between the Al foil and the PET film (Al / PET peel strength, initial peel strength, unit: N / 15 mm) was measured. The results are shown in Table 1. In the measurement of this peel strength, a PET film generally used as a base material or surface layer was used while being conscious of the electronic tag, and an Al foil was used in consideration of the circuit line.

[0165] <Water resistance test> Test pieces were prepared in the same manner as the measurement of the Al / PET peel strength. After the obtained test pieces were allowed to stand at 60 °C and 95% relative humidity for 30 days, the peel strength (peel strength after the water resistance test, unit: N / 15 mm) was measured in the same manner as the measurement of the Al / PET peel strength. The ratio of the peel strength after the water resistance test to the initial peel strength was calculated as the peel strength retention rate, and the water resistance was evaluated according to the following criteria. The results are shown in Table 1. ◎: Peel strength retention rate is 90% or more ○: Peel strength retention rate is 80% or more and less than 90% △: Peel strength retention rate is 60% or more and less than 80% ×: Peel strength retention rate is less than 60%

[0166] <Chemical resistance test> Test pieces were prepared in the same manner as the measurement of the Al / PET peel strength. After the obtained test pieces were immersed in a 10% sodium hydroxide aqueous solution at 40 °C for 30 days, the peel strength (peel strength after the chemical resistance test, unit: N / 15 mm) was measured in the same manner as the measurement of the Al / PET peel strength. The ratio of the peel strength after the chemical resistance test to the initial peel strength was calculated as the peel strength retention rate, and the chemical resistance was evaluated according to the following criteria. The results are shown in Table 1. ◎: Peel strength retention rate is 80% or more ○: Peel strength retention rate is 70% or more and less than 80% △: Peel strength retention rate is 60% or more and less than 70% ×: Peel strength retention rate is less than 60%

[0167] <Tackiness of the coating film> The adhesives of Examples 1 to 7 and Comparative Example 1 were respectively coated on an Al foil (thickness: 30 μm) and dried at 100 °C for 1 minute (dry film thickness: about 3 μm). Further, it was cured at 60 °C for 3 days. The tackiness of the obtained coating film was evaluated by touch and judged according to the following criteria. The results are shown in Table 1. ◎: No stickiness at all ○: Slight stickiness is recognized △: There is stickiness ×: There is very strong stickiness.

[0168] An electronic tag was produced by bonding a PET film (surface layer) to an inlet film equipped with circuit lines and an IC chip on a PET film using the adhesives obtained in Examples 1 to 7 and Comparative Example 1. When the read distance was measured in a non-contact transmission and reception test using the obtained electronic tags, the electronic tags using the adhesives obtained in Examples 1 to 7 had a longer read distance than the electronic tags using the adhesive obtained in Comparative Example 1. In particular, the electronic tags using the adhesives obtained in Examples 1 to 3 had a long read distance. Also, the operability of the electronic tags using the adhesives obtained in Examples 1 to 7 after storage at 60°C and 95% humidity for 30 days was also better than that of the electronic tags using the adhesive obtained in Comparative Example 1.

[0169] [Table 1] [Description of Reference Numerals]

[0170] 1: Base material 2: Adhesive layer 3: Surface layer 4: Circuit line 5: IC chip 6: Adhesive layer 7: Adhesive layer or pressure-sensitive adhesive layer 8: Support or release layer 10: Electronic tag

Claims

1. An adhesive for an electronic tag, which contains only a thermoplastic elastomer with respect to the non-volatile content of the adhesive for the electronic tag, wherein the thermoplastic elastomer contains a modified styrene-based elastomer obtained by modifying a styrene-based elastomer with a monomer having at least one functional group selected from a carboxyl group and an acid anhydride group, or the thermoplastic elastomer contains the modified styrene-based elastomer and a modified olefin-based elastomer obtained by modifying an olefin-based elastomer with a monomer having at least one functional group selected from a carboxyl group and an acid anhydride group, the olefin-based elastomer is a propylene / 1-butene copolymer, the styrene-based elastomer is at least one selected from a styrene-ethylene-butylene-styrene block copolymer (SEBS) and a styrene-ethylene-propylene-styrene block copolymer (SEPS), and the adhesive for an electronic tag that satisfies the following requirements (1) and (2). (1) The relative permittivity measured at a frequency of 1 kHz of the layer obtained from the adhesive is 4 or less. (2) The dielectric tangent measured at frequencies of 1 kHz, 10 kHz, 100 kHz, 1 MHz, and 10 GHz of the layer obtained from the adhesive is all 0.10 or less.

2. The adhesive for an electronic tag according to claim 1, wherein the olefin-based elastomer has a heat of fusion of 0 to 50 J / g measured according to JIS K7122.

3. Furthermore, the adhesive for an electronic tag according to claim 1 or 2, which contains a hydrocarbon-based synthetic oil.

4. An electronic tag having at least one electronic member selected from a circuit line and an IC chip via an adhesive layer formed from the adhesive for an electronic tag according to any one of claims 1 to 3 on a substrate.

5. On a substrate, at least one electronic component selected from circuit lines and IC chips is arranged, has a surface layer on the side opposite to the substrate of the electronic component, and the electronic component and the surface layer are adhered with the adhesive for electronic tags according to any one of claims 1 to 3, an electronic tag.

6. On a substrate, at least one electronic component selected from circuit lines and IC chips is arranged, has a surface layer on the side opposite to the substrate of the electronic component, and the substrate and the surface layer are adhered with the adhesive for electronic tags according to any one of claims 1 to 3, an electronic tag.

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