WO2020162231A1

WO2020162231A1 - Adhesive sheet and use thereof

Info

Publication number: WO2020162231A1
Application number: PCT/JP2020/002582
Authority: WO
Inventors: 拓三由藤
Original assignee: 日東電工株式会社
Priority date: 2019-02-06
Filing date: 2020-01-24
Publication date: 2020-08-13
Also published as: KR20210123364A; TWI808302B; JP7412082B2; JP2020125436A; KR102598588B1; CN113382860B; CN113382860A; TW202045653A

Abstract

Provided is a novel adhesive sheet suitably used for simultaneous batch inspection of a plurality of electrically-conductive small pieces. This adhesive sheet comprises an adhesive agent layer. The adhesive agent layer has a surface resistance value of 1.0 × 108 Ω/□ or less. In addition, this adhesive sheet has an adhesive strength in the range of 0.01-4.0 N/20 mm with respect to a stainless steel sheet.

Description

Adhesive sheet and its use

The present invention relates to an adhesive sheet and its use.
This application claims priority based on Japanese Patent Application No. 2019-020095 filed on February 6, 2019, the entire content of which is incorporated herein by reference.

Generally, a pressure-sensitive adhesive (also referred to as a pressure-sensitive adhesive. The same applies hereinafter) takes the form of a soft solid (viscoelastic body) in the temperature range near room temperature and has the property of easily adhering to an adherend by pressure. The pressure-sensitive adhesive is in the form of a pressure-sensitive adhesive sheet with a support having a pressure-sensitive adhesive layer on a support, or in the form of a support-less pressure-sensitive adhesive sheet having no support, from the viewpoint of good workability in attaching to an adherend. , Widely used in various fields. Such an adhesive can be removed from the adherend after adhering to the adherend and finishing its purpose of adhesion.

Patent Documents

1 and 2 are cited as prior art documents disclosing this type of conventional technology.

Patent Documents

1 and 2 relate to a surface protective film that temporarily protects a polarizing plate attached to a liquid crystal cell in the production of a liquid crystal display panel, and discloses a pressure-sensitive adhesive having an antistatic property.

Japanese Patent No. 5061898 Japanese Patent No. 5535987

By the way, the production volume of various semiconductor devices used in electronic products with display functions is increasing year by year, and due to demands for product miniaturization and higher performance, the device miniaturization is also progressing. Therefore, the problems of inspectability of the device and increase in the time required for the inspection are being faced. Specifically, for a semiconductor chip such as a light emitting diode, for example, in order to guarantee the quality, the energization inspection is performed on all the formed many chips in the manufacturing process. In this inspection, the probe pins are brought into direct contact with the electrodes of each chip to energize them to identify defective products and chip grading. However, due to the downsizing of the chip described above, the electrode area is also reduced, and it is becoming difficult to accurately bring the probe pin into contact with the microelectrode. Further, as described above, since the inspection is performed on a chip-by-chip basis, it is possible to perform inspection on a smaller chip than on a chip-by-wafer basis (typically a dicing process or an expanding process). Significant increase in time required.

The inventors of the present invention have come up with a new solution that is different from the conventional one, with respect to the technical limitations and the decrease in productivity as described above. The idea is that a plurality of conductive pieces (for example, semiconductor chips) are fixed with a conductive adhesive, and at the same time, the electrodes of the conductive pieces are brought into contact with the adhesive, and a current is applied to each conductive piece through this adhesive. By injecting, the conductive small pieces on the adhesive are inspected simultaneously and collectively. Based on this idea, the present invention has been completed as a result of studying the realization of a configuration suitable for simultaneous inspection of a plurality of conductive small pieces. That is, an object of the present invention is to provide a novel pressure-sensitive adhesive sheet that can be suitably used for collective simultaneous inspection of a plurality of conductive pieces. Another object of the present invention is to provide a method of making a tested conductive strip.

According to the present specification, a pressure-sensitive adhesive sheet including a pressure-sensitive adhesive layer is provided. The surface resistance value of the pressure-sensitive adhesive layer is 1.0×10 ⁸ Ω/□ or less. Further, this adhesive sheet has an adhesive force with respect to a stainless steel plate within a range of 0.01 to 4.0 N/20 mm.

Since the pressure-sensitive adhesive sheet having the above-described configuration has the pressure-sensitive adhesive layer having a predetermined electrical conductivity or more, by fixing a plurality of conductive small pieces (for example, semiconductor chips) on the pressure-sensitive adhesive layer, the pressure-sensitive adhesive layer passes through the pressure-sensitive adhesive layer, and thus the pressure-sensitive adhesive layer is formed on the pressure-sensitive adhesive. Simultaneous simultaneous energization of a plurality of arranged conductive pieces can be performed. Further, by setting the adhesive force of the pressure-sensitive adhesive sheet to a specific range, the conductive small piece can be fixed with good adhesion reliability, and after the energization step, the conductive small piece can be well separated from the pressure-sensitive adhesive layer surface. ..

In some preferred embodiments, the pressure-sensitive adhesive sheet has a haze value of 50% or less. According to the pressure-sensitive adhesive sheet whose haze value is limited to a predetermined value or less, the adherend fixed to the pressure-sensitive adhesive sheet can be inspected through the pressure-sensitive adhesive sheet.

In some preferred embodiments, the adhesive layer comprises oxyalkylene structural units. According to the pressure-sensitive adhesive layer containing the oxyalkylene structural unit, good conductivity is easily obtained, and compatibility between conductivity and transparency is easily realized.

In some embodiments, the pressure-sensitive adhesive layer preferably contains a polymer having the oxyalkylene structural unit. By using a polymer having an oxyalkylene structural unit, a pressure-sensitive adhesive layer having good conductivity and having both adhesion reliability and adherence separation/removability can be preferably obtained. In some embodiments, the polymer having the oxyalkylene structural unit has the oxyalkylene structural unit in the side chain. By providing the oxyalkylene structural unit on the side chain having a higher degree of freedom of movement than that of the polymer main chain, higher conductivity can be easily obtained based on the degree of freedom.

In some preferred embodiments, the content of the oxyalkylene structural unit in the pressure-sensitive adhesive layer is 20 to 95% by weight. By including a predetermined amount of the oxyalkylene structural unit in the pressure-sensitive adhesive layer, it is easy to obtain high conductivity, and it is easy to achieve both adhesion reliability and adherence separation/removability.

In some preferred embodiments, the adhesive layer contains an ionic compound. By containing an ionic compound, the pressure-sensitive adhesive layer can preferably exhibit high conductivity. In addition, the use of an ionic compound is preferable in that the transparency of the pressure-sensitive adhesive layer is maintained. Further, it is advantageous in that the pressure-sensitive adhesive layer can be made thinner than metal particles.

The pressure-sensitive adhesive sheet according to some preferred embodiments further includes a base material layer. The pressure-sensitive adhesive layer is provided on at least one surface (for example, one surface) of the base material layer. Since the pressure-sensitive adhesive sheet including the base material layer has a predetermined rigidity, it can be excellent in workability and handleability. The base material layer according to a more preferred embodiment is composed of a resin film having an elastic modulus of 50 MPa or more.

In some preferred embodiments, an undercoat layer is arranged between the base material layer and the pressure-sensitive adhesive layer. By providing the undercoat layer, the anchoring property of the pressure-sensitive adhesive layer is improved, and adhesive residue on the adherend during peeling is preferably prevented.

The present specification also provides a method for manufacturing an inspected conductive piece (eg, a semiconductor chip). This method includes: preparing a pressure-sensitive adhesive sheet to which a plurality of conductive pieces to be inspected are fixed, wherein the pressure-sensitive adhesive sheet has an adhesive layer having conductivity, The small piece is detachably fixed to the surface of the pressure-sensitive adhesive layer; at least a part of the plurality of conductive small pieces to be inspected is energized through the pressure-sensitive adhesive layer, and the conductive small piece to be inspected in the energized state. And a step of inspecting. According to the above method, it is possible to carry out simultaneous energization inspection of a plurality of conductive pieces at the same time. This method may typically further include a step of bringing a surface of the plurality of conductive strips to be inspected, which is opposite to a surface fixed to the adhesive layer, into contact with a conductive material before the inspection step. In this method, in the inspection step, the conductive small piece to be inspected is energized via the adhesive layer and the conductive material.
The method of manufacturing the inspected conductive piece may be an inspection method of the conductive piece (for example, a semiconductor chip).

In addition, in some embodiments, the above method includes a step of fixing a conductive wafer to an adhesive sheet before the step of preparing an adhesive sheet to which conductive pieces (for example, semiconductor chips) are fixed, Processing and forming the plurality of conductive pieces from the conductive wafer. The conductive wafer processing step may include a conductive wafer dicing step and an expansion step. In some other embodiments, a plurality of conductive pieces formed using different adhesive sheets or by different methods are fixed to the adhesive sheet before the step of preparing the adhesive sheet to which the conductive pieces are fixed. Can include steps. The pressure-sensitive adhesive sheet disclosed herein is suitable as the pressure-sensitive adhesive sheet used in the above method. As the conductive material used in the above method, the pressure-sensitive adhesive sheet disclosed herein is preferable, or a metal plate or a known or common conductive pressure-sensitive adhesive sheet may be used. In some embodiments, the step of inspecting the conductive piece to be inspected may include an inspection means such as a camera or a visual inspection through the adhesive sheet (for example, inspection of emission intensity or light wavelength of the light emitting semiconductor element).

It is a typical sectional view showing the example of composition of the adhesive sheet concerning one embodiment. It is a typical sectional view showing the example of composition of the adhesive sheet concerning other one embodiment. It is a typical sectional view explaining electric conduction inspection of a conductive piece concerning one embodiment.

A preferred embodiment of the present invention will be described below. It should be noted that matters other than matters particularly referred to in the present specification, which are necessary for carrying out the present invention, are based on the teachings for carrying out the invention described in the present specification and the common general knowledge at the time of application. Can be understood by those skilled in the art. The present invention can be carried out based on the contents disclosed in this specification and the common general technical knowledge in the field. Further, in the following drawings, members/sites having the same action may be described with the same reference numerals, and redundant description may be omitted or simplified. In addition, the embodiments described in the drawings are schematically illustrated for clearly explaining the present invention, and do not necessarily represent the size or scale of the product actually provided.

As used herein, the term "adhesive" refers to a material that is in the state of a soft solid (viscoelastic body) in a temperature range near room temperature and has the property of easily adhering to an adherend by pressure. .. The adhesive referred to here generally has a complex tensile modulus E ^* (1 Hz) as defined in “C. A. Dahlquist, “Adhesion: Fundamental and Practice”, McLaren & Sons, (1966) P. 143”. It may be a material having a property satisfying <10 ⁷ dyne/cm ² (typically, a material having the above property at 25° C.).

<Structure example of adhesive sheet>
The pressure-sensitive adhesive sheet disclosed herein may be a pressure-sensitive adhesive sheet with a substrate in which the above-mentioned pressure-sensitive adhesive layer is provided on one or both sides of a non-releasing substrate (supporting substrate), and the pressure-sensitive adhesive layer has a release liner. It may be a pressure-sensitive adhesive sheet that does not have a base material (that is, a pressure-sensitive adhesive sheet that does not have a non-peelable base material) and is held by the above. The concept of the adhesive sheet here may include what is called an adhesive tape, an adhesive label, an adhesive film and the like. In addition, the pressure-sensitive adhesive sheet disclosed herein may be in a roll shape or a sheet shape. Alternatively, it may be a pressure-sensitive adhesive sheet further processed into various shapes.

Figure 1 shows an example of the configuration of the PSA sheet disclosed here. The adhesive sheet 1 includes a base material layer 10 and an adhesive layer 20. The pressure-sensitive adhesive layer 20 is provided on one surface (first surface) 10A of the base material layer 10. Although described later in detail, the pressure-sensitive adhesive layer 20 has conductivity. The surface (adhesive surface) 20A of the adhesive layer 20 has a structure protected by a release liner (not shown) having a release surface on at least the adhesive layer side. Alternatively, the other surface 10B of the base material layer 10 is a release surface, and when the pressure-sensitive adhesive sheet 1 is wound, the pressure-sensitive adhesive layer 20 contacts the other surface 10B, and the adhesive surface 20A is the other surface of the base material layer. It may be protected by 10B.

FIG. 2 shows another example of the structure of the single-sided adhesive pressure-sensitive adhesive sheet. The pressure-sensitive adhesive sheet 2 shown in FIG. 2 includes a base material layer 10 and a pressure-sensitive adhesive layer 20, and further includes an undercoat layer 30 between the base material layer 10 and the pressure-sensitive adhesive layer 20. Specifically, one surface 30B of the undercoat layer 30 is in contact with the base material layer 10, and the other surface (surface opposite to the one surface) 30A of the undercoat layer 30 is in close contact with the adhesive layer 20. ing. By having such an undercoat layer 30, the anchoring property of the pressure-sensitive adhesive layer 20 is improved, and adhesive residue is prevented from being generated at the time of separation and removal from the adherend. As will be described later in detail, the undercoat layer 30 may have conductivity.

<Adhesive layer>
(Surface resistance value)
The pressure-sensitive adhesive layer of the pressure-sensitive adhesive sheet disclosed herein has a surface resistance value of 1.0×10 ⁸ Ω/□ or less (for example, less than 1.0×10 ⁸ Ω/□) in some typical embodiments. Is characterized by being. Thus, the pressure-sensitive adhesive layer whose surface resistance value is limited to a predetermined value or less has good conductivity, and the adherend can be energized through the pressure-sensitive adhesive layer. From the viewpoint of conductivity suitable for energization of the adherend, the surface resistance value is preferably 1.0×10 ⁷ Ω/□ or less (for example, less than 1.0×10 ⁷ Ω/□), and more preferably 1.0×10 ⁶ Ω/□ or less (for example, less than 1.0×10 ⁶ Ω/□), more preferably 5.0×10 ⁵ Ω/□ or less, particularly preferably 1.0×10 ⁵ Ω/□. Or less (for example, 5.0×10 ⁴ Ω/□ or less). The lower limit of the surface resistance value is not particularly limited and is usually 1.0×10 ² Ω/□ or more, and 1.0×10 ³ Ω/□ or more (for example, 1.0×10 ⁴ Ω/□ or more). May be The surface resistance value of the pressure-sensitive adhesive layer is measured by the method described in Examples below. The pressure-sensitive adhesive sheet disclosed in the present specification includes a mode in which the surface resistance value of the pressure-sensitive adhesive layer is not limited, and in such a mode, the pressure-sensitive adhesive layer is limited to those having the above-mentioned surface resistance value. Not done.

(Haze value)
The haze value of the pressure-sensitive adhesive layer is not particularly limited and may be, for example, about 80% or less. When the adherend is inspected through the pressure-sensitive adhesive sheet, the pressure-sensitive adhesive layer needs to have appropriate permeability. From such a viewpoint, the haze value of the pressure-sensitive adhesive layer is appropriately about 50% or less (for example, about 30% or less), preferably about 10% or less, more preferably about 3% or less, and further preferably. It is about 1% or less (for example, less than 0.1%). The haze value is measured by the method described in Examples below.

(Oxyalkylene structural unit)
In some preferred embodiments, the pressure-sensitive adhesive layer (which may be a pressure-sensitive adhesive composition, and the same applies hereinafter unless otherwise specified) contains an oxyalkylene structural unit. According to the pressure-sensitive adhesive layer containing the oxyalkylene structural unit, good conductivity is easily obtained, and compatibility between conductivity and transparency is easily realized. As an aspect of the pressure-sensitive adhesive layer containing an oxyalkylene structural unit, a polymer or oligomer having an oxyalkylene structural unit, the use of any of the other additives, or a combination of a plurality of them is mentioned, among which, oxyalkylene The use of polymers having structural units is preferred. By using such a polymer as the main component (base polymer) in the pressure-sensitive adhesive, the oxyalkylene structural unit can be contained in the entire system at a predetermined content rate.

The oxyalkylene structural unit contained in the adhesive layer is defined as a (poly)oxyalkylene unit. Examples of the (poly)oxyalkylene unit include units composed of (poly)oxyethylene and (poly)oxypropylene. These units are typically the addition of ethylene oxide, propylene oxide, and poly(ethylene glycol). Obtained by addition of alkylene glycol. The oxyalkylene structural unit preferably contains a polyoxyethylene unit.

The number of moles of the (poly)oxyalkylene unit in the oxyalkylene structural unit (also referred to as the number of addition moles, typically the number of repeating oxyalkylenes) is usually 1 or 2 or more. From the viewpoint of improving the mobility (electron conductivity) of electrons (which may be in the form of ions) in the pressure-sensitive adhesive layer, it is suitable that the number of moles of the (poly)oxyalkylene unit is greater than 2. It is preferably 3 or more, more preferably 5 or more, and further preferably 7 or more (for example, 8 or more). The upper limit of the number of moles of the (poly)oxyalkylene unit is not particularly limited, and from the viewpoint of the synthetic property (ease of polymerization) of the polymer having the oxyalkylene structural unit (the ease of polymerization) and the handling property, it is suitable to be less than 30. Yes, preferably less than 20, for example, 15 or less, 13 or less, 11 or less (typically 10 or less). In a mode in which a polymer or oligomer having an oxyalkylene structural unit is used, the number of moles of (poly)oxyalkylene units in the oxyalkylene structural unit of the polymer or oligomer may be selected from the above range.

The content ratio of the oxyalkylene structural unit in the pressure-sensitive adhesive layer (which may be the solid content of the pressure-sensitive adhesive composition) is set according to the electrical conductivity to the adherend and the like, and thus is not limited to a specific range. The content ratio of the oxyalkylene structural unit in the pressure-sensitive adhesive layer can be, for example, about 5% by weight or more, and from the viewpoint of improving conductivity, it is suitable to be about 10% by weight or more, preferably about 20% by weight. % Or more, more preferably about 30% by weight or more, further preferably about 40% by weight or more, particularly preferably about 50% by weight or more (for example, about 60% by weight or more). The upper limit of the content ratio of the oxyalkylene structural unit in the pressure-sensitive adhesive layer is appropriately about 95% by weight or less in consideration of adhesion reliability and adherend separation/removability, and for example, about 85% by weight or less. However, it may be about 75% by weight or less, or about 65% by weight or less (for example, about 55% by weight or less).

(polymer)
In the technology disclosed herein, the type of the adhesive forming the adhesive layer is not particularly limited. The above-mentioned pressure-sensitive adhesive (which may also be a pressure-sensitive adhesive composition) is an acrylic polymer, rubber-based polymer, polyester-based polymer, urethane-based polymer, polyether-based polymer, silicone-based polymer, polyamide-based polymer known in the field of pressure-sensitive adhesives. , One type or two or more types of various rubber-like polymers such as fluoropolymers. From the viewpoint of adhesive performance and cost, it is preferable to use an acrylic polymer or urethane polymer. Above all, a pressure-sensitive adhesive containing an acrylic polymer as a main component (acrylic pressure-sensitive adhesive) is more preferable.

The “acrylic polymer” refers to a polymer containing a monomer unit derived from a monomer having at least one (meth)acryloyl group in one molecule as a monomer unit constituting the polymer. Hereinafter, a monomer having at least one (meth)acryloyl group in one molecule is also referred to as an “acrylic monomer”. Therefore, an acrylic polymer in this specification is defined as a polymer containing a monomer unit derived from an acrylic monomer. A typical example of the acrylic polymer is an acrylic polymer in which the proportion of the acrylic monomer is more than 50% by weight based on all the monomer components used in the synthesis of the acrylic polymer.
In addition, “(meth)acryloyl” means a generic term for acryloyl and methacryloyl. Similarly, "(meth)acrylate" means acrylate and methacrylate, and "(meth)acrylic" means acrylic and methacrylic, respectively.

The "urethane-based polymer" is a polymer containing a polyol and a polyfunctional isocyanate as a unit constituting the polymer, in which a hydroxyl group of the polyol and an isocyanate group of the polyfunctional isocyanate are polymerized by a urethane bond (polyaddition). Say. The polyol and the polyfunctional isocyanate before the reaction are typically present in the form of a monomer or an oligomer (hereinafter may be collectively referred to as “monomer”), and the urethane-based polymer obtained by the above reaction is typically Has a structure in which segments derived from a polyol and segments derived from a polyfunctional isocyanate are alternately repeated. The above-mentioned monomer includes what is called a macromonomer.
In addition, the term “oligomer” used herein refers to a polymer having a molecular weight of less than 3.0×10 ⁴ . As the molecular weight of the oligomer, a weight average molecular weight (Mw) in terms of standard polystyrene determined by gel permeation chromatography (GPC) or a molecular weight calculated from a chemical formula is adopted.

(Polymer having oxyalkylene structural unit)
In some preferred embodiments, the pressure-sensitive adhesive layer (which may be the pressure-sensitive adhesive composition) contains a polymer containing an oxyalkylene structural unit. Thereby, good conductivity is easily obtained. The oxyalkylene structural unit-containing polymer may have an oxyalkylene structural unit in its main chain or side chain. The oxyalkylene structural unit may be incorporated in the structure of the polymer (for example, in the network structure). Above all, it is more preferable to use a polymer having an oxyalkylene structural unit in the side chain. By disposing the oxyalkylene structural unit in the side chain, high conductivity is easily obtained due to the high degree of freedom. In the structure having an oxyalkylene structural unit in the polymer side chain, the chemical structure of the side chain is not particularly limited as long as it has an oxyalkylene structural unit. The polymer side chain can be in the form of, for example, (poly)oxyalkylene monoalcohol, (poly)oxyalkylene monoalkyl ether. The form of the side chain terminal is not particularly limited, and may be an alkyl group such as a methyl group, a phenyl group, or the like, and may be a functional group such as a hydroxyl group.

The content of the oxyalkylene structural unit in the oxyalkylene structural unit-containing polymer is not limited to a specific range because it is set according to the electrical conductivity to the adherend. The proportion of the oxyalkylene structural unit in the polymer can be, for example, about 10% by weight or more, and from the viewpoint of improving the conductivity, it is suitable to be about 25% by weight or more, preferably about 35% by weight or more. It is more preferably about 45% by weight or more, further preferably about 55% by weight or more, and particularly preferably about 65% by weight or more (for example, about 70% by weight or more). The upper limit of the proportion of the oxyalkylene structural unit in the polymer is not particularly limited, and it is suitable to be about 95% by weight or less in consideration of the adhesion reliability, the adherend separation-removability, etc., for example, about 90% by weight. It may be less than or equal to about 85% by weight, or about 75% by weight or less (for example, about 70% by weight or less).

The oxyalkylene structural unit-containing polymer can be obtained by polymerizing a monomer having an oxyalkylene structural unit. The polymerization method is not particularly limited and may be radical polymerization, ionic polymerization, polycondensation, polyaddition or the like. Alternatively, for example, a polymer having an oxyalkylene structural unit can also be obtained by adding an oxyalkylene structural unit to the polymer. For example, a method of adding a compound having an oxyalkylene structural unit such as polyethylene glycol (PEG) to a polymer obtained by a conventional method by a known or common method can be mentioned. According to this method, a polymer having an oxyalkylene structural unit in its side chain can be preferably obtained.

The monomer having an oxyalkylene structural unit is, in some embodiments, a compound having a polymerizable reactive group such as a vinyl group or a (meth)acryloyl group, and an oxyalkylene structural unit. For example, an acrylic monomer having an oxyalkylene structural unit, a vinyl ether monomer having an oxyalkylene structural unit, a polycarboxylic acid monomer having an oxyalkylene structural unit (for example, a compound containing an oxyalkylene structural unit such as PEG is used as maleic anhydride, etc. (E.g. esterified) is exemplified. From the viewpoint of polymerizability, it is preferable to use an acrylic monomer having an oxyalkylene structural unit.

(Acrylic polymer having oxyalkylene structural unit)
In some preferred embodiments, the oxyalkylene structural unit-containing polymer is an acrylic polymer having oxyalkylene structural units. Hereinafter, as a preferable example, an oxyalkylene structural unit-containing acrylic polymer will be mainly described, but it is not intended to limit the oxyalkylene structural unit-containing polymer disclosed herein to an acrylic polymer.

The oxyalkylene structural unit-containing acrylic polymer can be preferably obtained by polymerizing an acrylic monomer having an oxyalkylene structural unit. The oxyalkylene structural unit-containing acrylic monomer includes a (poly)oxyethylene unit-containing acrylic monomer, a (poly)oxypropylene unit-containing acrylic monomer, and a (poly)oxyethylene unit- and (poly)oxypropylene unit-containing acrylic monomer. One type or two or more types of system monomers can be used.

Examples of the (poly)oxyethylene unit-containing acrylic monomer include alkoxy (poly)ethylene glycol (meth)acrylate such as methoxy polyethylene glycol (meth)acrylate and ethoxy polyethylene glycol (meth)acrylate; polyethylene glycol (meth)acrylate and the like ( Poly)ethylene glycol (meth)acrylate; and the like. Examples of the (poly)oxypropylene unit-containing acrylic monomer include alkoxy (poly)propylene glycol (meth)acrylate such as methoxy polypropylene glycol (meth)acrylate and ethoxy polypropylene glycol (meth)acrylate; polypropylene glycol (meth)acrylate and the like ( Poly)propylene glycol (meth)acrylate; and the like. These may be used alone or in combination of two or more. Above all, it is preferable to use a (poly)oxyethylene unit-containing acrylic monomer from the viewpoint of electron conductivity. In the above-mentioned monomer, the terminal on the oxyalkylene structural unit side may be an alkyl group such as a methyl group, a phenyl group or the like, or a functional group such as a hydroxyl group. The terminal structure of the monomer can be appropriately set in consideration of the crosslinking reaction and the like.

The amount of the oxyalkylene structural unit-containing monomer (preferably the oxyalkylene structural unit-containing acrylic monomer) used is not limited to a specific range because it is set according to the electrical conductivity to the adherend and the adhesive property. The amount of the oxyalkylene structural unit-containing monomer used is approximately 10 mol% or more (for example, 30 mol% or more) of the total amount of the monomers used for the synthesis of the oxyalkylene structural unit-containing polymer (hereinafter also referred to as “all monomer components”). be able to. From the viewpoint of improving conductivity, the amount of the oxyalkylene structural unit-containing monomer used in the total amount of monomers is appropriately about 30 mol% or more, preferably about 45 mol% or more, more preferably about 55 mol% or more, further It is preferably about 65 mol% or more, particularly preferably about 75 mol% or more (for example, about 80 mol% or more). From the viewpoint of cohesiveness and adhesive strength, the amount of the oxyalkylene structural unit-containing monomer used in the total amount of monomers is appropriately about 95 mol% or less, preferably about 90 mol% or less, and about 80 mol. % Or less, about 70 mol% or less, or about 60 mol% or less (for example, about 50 mol% or less).

As the oxyalkylene structural unit-containing polymer in the technology disclosed herein, those obtained by copolymerizing a monomer having a hydroxyl group (—OH) can be preferably used. Specific examples of the hydroxyl group-containing monomer include 2-hydroxyethyl (meth)acrylate, 2-hydroxypropyl (meth)acrylate, 3-hydroxypropyl (meth)acrylate, 2-hydroxybutyl (meth)acrylate and 4-hydroxybutyl ( Examples thereof include hydroxyl group-containing acrylic monomers such as (meth)acrylate. These hydroxyl group-containing monomers may be used alone or in combination of two or more. A polymer in which such a monomer is copolymerized is preferable because it is easy to obtain a pressure-sensitive adhesive that achieves both adhesion and fixation of an adherend and separation and removal. For example, since it becomes easy to control the peeling force from the adherend to be low, it is easy to obtain a pressure-sensitive adhesive that is excellent in separating and removing the adherend. In addition, the shorter the hydroxyl group-containing side chain in the polymer is, the more easily the effect of improving cohesive force can be obtained. Therefore, the distance from the polymerizable reactive group (typically (meth)acryloyl group) of the hydroxyl group-containing monomer to the hydroxyl group A short-chain hydroxyl group-containing monomer (in the case of hydroxy(meth)acrylate, a monomer having a hydroxyalkyl group having a small number of carbon atoms) is preferably used.

From the viewpoint of sufficiently exerting the effect of using the monomer, the hydroxyl group-containing monomer is appropriately used in a proportion of about 1 mol% or more of the total amount of the monomers used for the synthesis of the oxyalkylene structural unit-containing polymer, and preferably It is about 3 mol% or more, more preferably about 5 mol% or more, even more preferably about 8 mol% or more, and may be about 12 mol% or more (about 15 mol% or more). Further, the amount of the hydroxyl group-containing monomer in the total amount of monomers used for the synthesis of the polymer is appropriately about 40 mol% or less, preferably about 30 mol% in consideration of cohesiveness and adhesive strength of the adhesive. Hereafter, it is more preferably about 20 mol% or less.

In some preferred embodiments, the oxyalkylene structural unit-containing polymer contains, as a monomer unit, a monomer having a homopolymer Tg (glass transition temperature) of about 10° C. or higher (high Tg monomer). By copolymerizing a high Tg monomer, the cohesiveness of the pressure-sensitive adhesive can be improved, and the adhesive strength can be improved. Further, there is a tendency that separation and removability such as adhesive residue prevention is improved. From the viewpoint of improving cohesiveness, in some embodiments, the Tg of a homopolymer of a high Tg monomer is suitably about 30° C. or higher (eg, about 50° C. or higher), and may be about 70° C. or higher, or about 90° C. It may be ℃ or more. Further, the upper limit of Tg of the homopolymer of the high Tg monomer is not particularly limited, and from the viewpoint of easiness of synthesizing the polymer and the like, it is usually suitable to be about 200°C or lower. In some embodiments, the Tg of the high Tg monomer homopolymer may be about 180° C. or less, about 150° C. or less, or about 120° C. or less.

The high Tg monomer is exemplified as a monomer that can be used for synthesizing a polymer containing an oxyalkylene structural unit, and one having a homopolymer Tg of a predetermined value or more can be used without particular limitation. For example, one or two or more kinds of monomers selected from alkyl(meth)acrylates exemplified below and other monomers such as various functional group-containing monomers can be used. Among them, alkyl (meth)acrylate is preferable, and among them, alkyl methacrylate (typically methyl methacrylate) in which the alkyl group has 1 to 4 carbon atoms can be preferably used.

The high Tg monomer can be used in a proportion of about 1 mol% or more of the total amount of monomers used for the synthesis of the oxyalkylene structural unit-containing polymer, and from the viewpoint of improving the cohesiveness of the pressure-sensitive adhesive and the adhesive strength, it is about 5 mol% or more. It is suitable to be about 10 mol% or more, more preferably about 15 mol% or more, and about 25 mol% or more (for example, about 35 mol% or more). Further, the amount of the high Tg monomer in the total amount of the monomers used for the synthesis of the polymer is appropriately about 60 mol% or less, preferably about 50 mol% or less, more preferably about 50 mol% in consideration of the adhesive strength. It is 40 mol% or less (for example, about 30 mol% or less). In some other aspects, the amount of high Tg monomer in the total monomer can be less than 10 mol% or less than 1 mol%. The oxyalkylene structural unit-containing polymer may be substantially free of high Tg monomer as a monomer unit.

The polymer containing an oxyalkylene structural unit disclosed herein may contain an alkyl (meth)acrylate as a monomer unit. The alkyl group contained in the alkyl (meth)acrylate may be a chain alkyl group or an alicyclic alkyl group. The number of carbon atoms in the alkyl group may be within the range of 1-20. Specific examples of such an alkyl(meth)acrylate include ethyl(meth)acrylate, butyl(meth)acrylate, isooctyl(meth)acrylate, 2-ethylhexyl(meth)acrylate, nonyl(meth)acrylate and the like.

The amount of the alkyl (meth)acrylate (for example, the alkyl (meth)acrylate that does not correspond to the above-mentioned high Tg monomer) is determined based on the total amount of the monomers used for the synthesis of the oxyalkylene structural unit-containing polymer from the viewpoint of cohesiveness and adhesive strength. It can be about 30 mol% or less, for example, about 10 mol% or less, or about 1 mol% or less. The oxyalkylene structural unit-containing polymer may be a polymer that does not substantially contain, as a monomer unit, an alkyl (meth)acrylate (for example, an alkyl (meth)acrylate that does not correspond to the high Tg monomer).

The oxyalkylene structural unit-containing polymer disclosed herein may be copolymerized with a monomer (other monomer) other than the oxyalkylene structural unit-containing monomer and the hydroxyl group-containing monomer. Such a monomer can be used, for example, for the purpose of adjusting the adhesive performance (for example, the ability to separate and remove the adherend). For example, as a monomer capable of improving the cohesive strength and heat resistance of an adhesive, a sulfonic acid group-containing monomer, a phosphoric acid group-containing monomer, a cyano group-containing monomer, vinyl esters such as vinyl acetate, an aromatic vinyl compound such as styrene, etc. Are listed. In addition, as a monomer (functional group-containing monomer) that can introduce a functional group that can serve as a cross-linking point into an acrylic polymer or contribute to the improvement of adhesive strength, a carboxyl group-containing monomer such as acrylic acid or methacrylic acid; maleic anhydride, etc. Acid anhydride group-containing monomer; amide group-containing monomer such as acrylamide; amino group-containing monomer; imide group-containing monomer; epoxy group-containing monomer; (meth)acryloylmorpholine, cyclic monomer having a nitrogen atom such as N-vinylpyrrolidone; Examples thereof include vinyl ethers. Further, as other monomer, a polyfunctional monomer can be used as a copolymerizable component for the purpose of crosslinking treatment and the like. As the polyfunctional monomer, one or more of hexanediol di(meth)acrylate, polyethylene glycol di(meth)acrylate, polypropylene glycol di(meth)acrylate and the like can be used. The above-mentioned other monomers may be used alone or in combination of two or more kinds.

The amount of the other monomer used may be about 30 mol% or less of the total amount of the monomers used for the synthesis of the oxyalkylene structural unit-containing polymer, from the viewpoint of sufficiently exhibiting the characteristics of the oxyalkylene structural unit-containing monomer. It may be about 10 mol% or less, or about 1 mol% or less. The oxyalkylene structural unit-containing polymer may be a polymer that does not substantially contain the above-mentioned other monomer as a monomer unit.

The method for obtaining the oxyalkylene structural unit-containing polymer is not particularly limited, and is known as a method for synthesizing a polymer (for example, an acrylic polymer) such as a solution polymerization method, an emulsion polymerization method, a bulk polymerization method, a suspension polymerization method, or a photopolymerization method. Various known polymerization methods can be appropriately adopted. For example, a solution polymerization method can be preferably adopted. The polymerization temperature at the time of solution polymerization can be appropriately selected according to the type of monomer and solvent used, the type of polymerization initiator, etc., and is, for example, about 20°C to 170°C (typically 40°C to 140°C). C.). Further, the polymer may be a random copolymer, a block copolymer, a graft copolymer, or the like. From the viewpoint of productivity and the like, a random copolymer is usually preferable.

The solvent (polymerization solvent) used for solution polymerization can be appropriately selected from conventionally known organic solvents. For example, aromatic compounds such as toluene (typically aromatic hydrocarbons); acetic acid esters such as ethyl acetate; aliphatic or alicyclic hydrocarbons such as hexane and cyclohexane; 1,2-dichloroethane, etc. Halogenated alkanes; isopropyl alcohol and other lower alcohols (eg, C1 to C4 monohydric alcohols); tert-butyl methyl ether and other ethers; methyl ethyl ketone and other ketones; Any one kind of solvent or a mixed solvent of two or more kinds can be used.

The initiator used for the polymerization can be appropriately selected from conventionally known polymerization initiators according to the type of the polymerization method. For example, one or more azo-based polymerization initiators such as 2,2'-azobisisobutyronitrile (AIBN) can be preferably used. Other examples of the polymerization initiator include persulfates such as potassium persulfate; peroxide initiators such as benzoyl peroxide and hydrogen peroxide; substituted ethane initiators such as phenyl-substituted ethane; aromatic carbonyl compounds. And the like. Still another example of the polymerization initiator is a redox type initiator obtained by combining a peroxide and a reducing agent. Such polymerization initiators may be used alone or in combination of two or more. The polymerization initiator may be used in a usual amount, for example, about 0.005 to 1 part by weight (typically about 0.01 to 1 part by weight) per 100 parts by weight of the monomer component. ) Can be selected from the range.

The oxyalkylene structural unit-containing polymer disclosed herein suitably has a weight average molecular weight (Mw) in terms of standard polystyrene obtained by GPC (gel permeation chromatography) of about 3×10 ⁴ or more. From the viewpoint of separation and removability of the adherend, etc., it is preferably about 10×10 ⁴ or more, more preferably about 20×10 ⁴ or more, and further preferably about 30×10 ⁴ or more. Further, the upper limit of the Mw is not particularly limited, and is suitably about 500×10 ⁴ or less, for example, and from the viewpoint of adhesive strength, coatability at the time of forming the adhesive layer, etc., preferably about 100×. It is 10 ⁴ or less, more preferably about 70×10 ⁴ or less, and may be about 50×10 ⁴ or less.

The dispersity (Mw/Mn) of the oxyalkylene structural unit-containing polymer disclosed herein is not particularly limited. The polydispersity (Mw/Mn) here means the polydispersity (Mw/Mn) represented by the ratio of the weight average molecular weight (Mw) to the number average molecular weight (Mn). In a preferred embodiment, the dispersity (Mw/Mn) of the oxyalkylene structural unit-containing polymer is appropriately about 15 or less, and from the viewpoint of preferably exhibiting the cohesiveness based on a relatively uniform high molecular weight polymer, It is preferably about 10 or less, more preferably about 7 or less. The Mw/Mn is theoretically 1 or more, and may be, for example, 2 or more, 3 or more, and 4 or more (typically 5 or more).

Specifically, the Mw and Mn can be measured under the following conditions using a trade name “HLC-8120GPC” (manufactured by Tosoh Corporation) as a GPC measuring device.
[GPC measurement conditions]
Sample concentration: 0.2 wt% (tetrahydrofuran solution)
Sample injection volume: 100 μL
Eluent: Tetrahydrofuran (THF)
Flow rate (flow rate): 0.8 mL/min Column temperature (measurement temperature): 40°C
Column: Tosoh Corp., G7000H _XL + GMH _XL + GMH _XL
Column size: Each 7.8 mm φ × 30 cm Total 90 cm
Detector: Differential refractometer (RI)
Standard sample: polystyrene

(Urethane Polymer Having Oxyalkylene Structural Unit)
In some embodiments, the pressure-sensitive adhesive layer may include a urethane-based polymer having an oxyalkylene structural unit. Urethane-based polymers containing oxyalkylene structural units typically have oxyalkylene structural units in the main chain skeleton, and in some embodiments (for example, a composition in which a polyol is blended in excess of a polyfunctional isocyanate), an oxyalkylene structural unit is used. The units can also have side chains. The oxyalkylene structural unit may be derived from any of the polyol that constitutes the urethane-based polymer and the polyfunctional isocyanate, but due to the ease of introduction into the polymer structure, the use of a polyol having an oxyalkylene structural unit The oxyalkylene structural unit can be introduced into the urethane polymer.

As the polyol used to form the urethane-based polymer, one or more suitable compounds can be selected from compounds having a plurality of hydroxyl groups and used. For example, one kind or two or more kinds of polyester polyol, polyether polyol, polycaprolactone polyol, polycarbonate polyol, castor oil-based polyol and the like can be used. Among them, polyester polyols and polyether polyols are preferably used, and polyether polyols are more preferable. Examples of the polyether polyol include poly(ethylene glycol), poly(propylene glycol), poly(tetramethylene glycol), polyoxyethylene glyceryl ether, polyoxypropylene glyceryl ether, and the like.

The average number of functional groups of the polyol used for forming the urethane polymer is about 2 or more, and from the viewpoint of improving cohesive force, it is appropriate to set it to about 2.5 or more (for example, about 2.8 or more). The average number of functional groups is usually about 5 or less, and from the viewpoint of adhesive strength and the like, it is suitable to be about 4 or less (for example, about 3.5 or less).

The molecular weight of the polyol is appropriately set depending on the conductivity, adhesive properties, etc., and thus is not limited to a specific range, and is usually about 300 or more, and about 500 or more is suitable, and preferably It may be about 800 or more, about 1000 or more, about 3000 or more, or about 5000 or more. The upper limit of the molecular weight of the above-mentioned polyol is, for example, less than 3.0×10 ⁴ , and it is suitable to set it to about 2.0×10 ⁴ or less, or about 1.5×10 ⁴ or less, or about 1.2. It may be x10 ⁴ or less (for example, less than 1.0 x 10 ⁴ ). The polyol may be a polymer having a number average molecular weight of about 10×10 ⁴ or less (for example, about 5×10 ⁴ or less).

In some preferred embodiments, the polyol used for forming the urethane-based polymer is one or two of a polyol serving as a main component (main polyol) and a sub-component polyol (sub-polyol) having a lower molecular weight than the main component. And more than one species. By using the primary polyol and the secondary polyol in combination, the effect of the technique disclosed herein can be preferably exerted or adjusted. The types of the main polyol and the sub-polyol are not particularly limited, and may be, for example, any one of polyester polyol, polyether polyol, polycaprolactone polyol, polycarbonate polyol, castor oil-based polyol and the like. Among them, polyester polyol and polyether polyol are preferable, and polyether polyol is more preferable. Specific examples of the polyether polyol include the polyether polyols exemplified above.

The molecular weight of the main polyol to be used is appropriately set depending on the conductivity, adhesive property, etc., and thus is not limited to a specific range, and is usually about 3,000 or more and about 5,000 or more (for example, about 8,000 or more). Is appropriate. The upper limit of the molecular weight of the main polyol is, for example, less than 3.0×10 ⁴ , and it is suitable to set it to about 2.0×10 ⁴ or less, and about 1.5×10 ⁴ or less (eg 1.2×10 4). ⁴ or less). As the sub-polyol, one or two or more polyols having a molecular weight smaller than that of the main polyol can be used. The molecular weight of the one or more secondary polyols may be about 300 or more, preferably about 500 or more, further about 800 or more, or about 1000 or more, for example about 1500 or more, and for example about 1.0×. It may be less than 10 ⁴ , preferably about 7,000 or less, further about 5000 or less, or about 2500 or less, for example about 1200 or less.

The average number of functional groups of the main polyol is about 2 or more, and it is appropriate to set it to about 2.5 or more (for example, about 2.8 or more) from the viewpoint of improving cohesive force. The average number of functional groups is usually about 5 or less, and from the viewpoint of adhesive strength and the like, it is suitable to be about 4 or less (for example, about 3.5 or less). The average number of functional groups of the sub-polyol is about 2 or more, and from the viewpoint of improving the cohesive force, it is suitable to be about 2.5 or more (for example, about 2.8 or more). The average number of functional groups is usually about 5 or less, and from the viewpoint of adhesive strength and the like, it is suitable to be about 4 or less (for example, about 3.5 or less).

In the embodiment in which the main polyol and the sub-polyol are used in combination as the polyol used to form the urethane polymer, the weight ratio of the main polyol and the sub-polyol (main polyol/sub-polyol) is not particularly limited, and for example, about 10/ It may be 90 or more, preferably about 25/75 or more, preferably about 50/50 or more, and about 70/30 or more (for example, about 80/20 or more). The above weight ratio (main polyol/sub-polyol) can be, for example, about 99/1 or less, and is appropriately about 95/5 or less (eg, about 90/10 or less).

As the polyfunctional isocyanate used for forming the urethane polymer, one or more appropriate compounds can be selected from compounds having a plurality of isocyanate groups and used. Examples of polyfunctional isocyanates are: aromatic diisocyanates such as tolylene diisocyanate, diphenylmethane diisocyanate and xylene diisocyanate; cycloaliphatic diisocyanates such as cyclopentylene diisocyanate, cyclohexylene diisocyanate and isophorone diisocyanate; butylene diisocyanate and hexamethylene diisocyanate. Aliphatic isocyanate; and the like. More specifically, trimethylolpropane/tolylene diisocyanate trimer adduct (manufactured by Tosoh Corporation, trade name "Coronate L"), trimethylolpropane/hexamethylene diisocyanate trimer adduct (manufactured by Tosoh Corporation, trade name) Isocyanate adducts such as "Coronate HL") and isocyanurate form of hexamethylene diisocyanate (trade name "Coronate HX" manufactured by Tosoh Corporation); and the like are preferable. Such polyfunctional isocyanates may be used alone or in combination of two or more.

The above polyol and the above polyfunctional isocyanate are blended so that the equivalent ratio of the OH group of the polyol and the NCO group of the polyfunctional isocyanate (NCO group/OH group) is in an appropriate range. The above equivalent ratio (NCO group/OH group) is usually about 5.0 or less, about 3.0 or less is suitable, about 2.5 or less, or about 2.0 or less. The equivalent ratio (NCO group/OH group) is usually about 0.1 or more (for example, about 0.2 or more), about 0.3 or more is suitable, and about 0.5 or more may be sufficient.

The content of the polyfunctional isocyanate for forming the urethane polymer can be set according to the equivalence ratio (NCO group/OH group) with the polyol, the polyol molecular weight, the polyfunctional isocyanate molecular weight, etc. It is not limited to. In the pressure-sensitive adhesive composition for forming the pressure-sensitive adhesive layer, the content of the polyfunctional isocyanate can be, for example, about 1 part by weight or more based on 100 parts by weight of the polyol, and about 5 parts by weight or more. It is suitable that the amount is about 10 parts by weight or more, and may be about 15 parts by weight or more. The upper limit of the content of the polyfunctional isocyanate with respect to 100 parts by weight of the polyol can be, for example, about 50 parts by weight or less, and it is appropriate that the upper limit is about 30 parts by weight, preferably about 25 parts by weight. The amount is below, and may be, for example, about 20 parts by weight or less.

The urethane-based polymer disclosed herein can be obtained by reacting the above-mentioned pressure-sensitive adhesive composition containing the polyol and the polyfunctional isocyanate under a predetermined temperature condition by using a catalyst if necessary. .. The reaction temperature is usually about 85°C or higher, for example, about 100°C or higher is suitable, and preferably about 115°C or higher. The upper limit of the reaction temperature is suitably 170° C. or lower, for example, and may be about 150° C. or lower.

The content ratio of the oxyalkylene structural unit-containing polymer in the pressure-sensitive adhesive layer disclosed herein is set according to the electrical conductivity to the adherend and the like, and thus is not limited to a specific range. The content ratio of the oxyalkylene structural unit polymer in the pressure-sensitive adhesive layer can be, for example, about 30% by weight or more, and about 50% by weight from the viewpoint of improving conductivity, compatibility of adhesion reliability and separability of adherend. % Or more (typically more than 50% by weight), preferably about 60% by weight or more, more preferably about 70% by weight or more, further preferably about 80% by weight or more, about 90% by weight. It may be more than weight %. The upper limit of the content ratio of the oxyalkylene structural unit polymer in the pressure-sensitive adhesive layer is appropriately about 95% by weight or less in consideration of adhesion reliability, adherend separation/removability, conductivity, etc. It may be 90% by weight or less.

(Ionic compound)
The pressure-sensitive adhesive layer disclosed herein (which may be a pressure-sensitive adhesive composition) preferably contains an ionic compound as a conductive component. By including the ionic compound, the pressure-sensitive adhesive layer can preferably exhibit good conductivity. Use of an ionic compound is preferable also from the viewpoint of maintaining the transparency of the pressure-sensitive adhesive layer. In the embodiment using the pressure-sensitive adhesive layer containing an oxyalkylene structural unit, the oxyalkylene structural unit in the pressure-sensitive adhesive layer serves as a transfer medium of the ionic compound, or by electrically supporting the ionic compound, It can exhibit excellent conductivity.

Examples of ionic compounds include alkali metal salts and ionic liquids. These may be used alone or in combination of two or more. Here, the “ionic liquid” (sometimes referred to as a room temperature molten salt) refers to a molten salt (ionic compound) which is liquid at 40° C. or lower. Since the ionic liquid is liquid at 40° C. or lower, it can be easily added to the pressure-sensitive adhesive and dispersed or dissolved in the temperature range as compared with a solid salt. Furthermore, since the ionic liquid does not have a vapor pressure (nonvolatile), it does not disappear over time and conductivity can be continuously exhibited.

(Alkali metal salt)
In some preferred embodiments, alkali metal salts are used as the ionic compound. Typical examples of alkali metal salts include lithium salts, sodium salts and potassium salts. For example, Li ⁺ , Na ⁺ or K ⁺ as a cation component and Cl ⁻ , Br ⁻ , I ⁻ , BF ₄ −, PF ₆ ⁻ , SCN ⁻ , ClO ₄ ⁻ , CF ₃ SO ₃ ⁻ , as an anion component. A metal salt composed of (FSO ₂ ) ₂ N ⁻ , (CF ₃ SO ₂ ) ₂ N ⁻ , (C ₂ F ₅ SO ₂ ) ₂ N ⁻ or (CF ₃ SO ₂ ) ₃ C ⁻ can be used. It is preferable to use a lithium salt because of its high dissociation property. As preferable specific examples, LiBr, LiI, LiBF ₄ , LiPF ₆ , LiSCN, LiClO ₄ , LiCF ₃ SO ₃ , Li(CF ₃ SO ₂ ) ₂ N, Li(C ₂ F ₅ SO ₂ ) ₂ N, Li( CF _₃ SO ₂₎ ₃ lithium salt of C, and the like. In particular, lithium salts whose anion component is a fluorine-containing anion such as bis(perfluoroalkylsulfonyl)imide anion and perfluoroalkylsulfonium anion (for example, Li(CF ₃ SO ₂ ) ₂ N, Li(C ₂ F ₅ SO ₂ ) ₂ N, LiCF ₃ SO ₃ ) are preferred. Such alkali metal salts may be used alone or in combination of two or more.

(Ionic liquid)
As the ionic liquid, one or more of nitrogen-containing onium salts, sulfur-containing onium salts and phosphorus-containing onium salts can be preferably used. In a preferred embodiment, the pressure-sensitive adhesive layer contains an ionic liquid having at least one organic cation component represented by any of the following general formulas (A) to (E).

Here, in the formula (A), R _a represents a hydrocarbon group having 4 to 20 carbon atoms or a functional group containing a hetero atom. R _b and R _{c, which} may be the same or different, each represents a hydrogen atom or a hydrocarbon group having 1 to 16 carbon atoms or a functional group containing a hetero atom. However, when the nitrogen atom contains a double bond, there is no R _c .
In the above formula (B), R _d represents a hydrocarbon group having 2 to 20 carbon atoms or a functional group containing a hetero atom. R _e , R _f and R _{g, which} may be the same or different, each represents a hydrogen atom or a hydrocarbon group having 1 to 16 carbon atoms or a functional group containing a hetero atom.
In the above formula (C), R _h represents a hydrocarbon group having 2 to 20 carbon atoms or a functional group containing a hetero atom. R _i , R _j and R _{k, which} may be the same or different, each represents a hydrogen atom or a hydrocarbon group having 1 to 16 carbon atoms or a functional group containing a hetero atom.
In the above formula (D), Z represents a nitrogen atom, a sulfur atom or a phosphorus atom. R ₁ , R _m , R _n and R _{o, which} may be the same or different, each represents a hydrocarbon group having 1 to 20 carbon atoms or a functional group containing a hetero atom. However, when Z is a sulfur atom, there is no R _o .
In the above formula (E), R _p represents a hydrocarbon group having 1 to 18 carbon atoms or a functional group containing a hetero atom.

Examples of the cation represented by the formula (A) include a pyridinium cation, a pyrrolidinium cation, a piperidinium cation, a cation having a pyrroline skeleton, and a cation having a pyrrole skeleton.

Specific examples of the pyridinium cation include 1-methylpyridinium, 1-ethylpyridinium, 1-propylpyridinium, 1-butylpyridinium, 1-pentylpyridinium, 1-hexylpyridinium, 1-heptylpyridinium, 1-octylpyridinium, 1 -Nonylpyridinium, 1-decylpyridinium, 1-allylpyridinium, 1-propyl-2-methylpyridinium, 1-butyl-2-methylpyridinium, 1-pentyl-2-methylpyridinium, 1-hexyl-2-methylpyridinium, 1-heptyl-2-methylpyridinium, 1-octyl-2-methylpyridinium, 1-nonyl-2-methylpyridinium, 1-decyl-2-methylpyridinium, 1-propyl-3-methylpyridinium, 1-butyl-3 -Methylpyridinium, 1-butyl-4-methylpyridinium, 1-pentyl-3-methylpyridinium, 1-hexyl-3-methylpyridinium, 1-heptyl-3-methylpyridinium, 1-octyl-3-methylpyridinium, 1-octyl-4-methylpyridinium, 1-nonyl-3-methylpyridinium, 1-decyl-3-methylpyridinium, 1-propyl-4-methylpyridinium, 1-pentyl-4-methylpyridinium, 1-hexyl-4 -Methylpyridinium, 1-heptyl-4-methylpyridinium, 1-nonyl-4-methylpyridinium, 1-decyl-4-methylpyridinium, 1-butyl-3,4-dimethylpyridinium and the like can be mentioned.

Specific examples of the pyrrolidinium cation include 1,1-dimethylpyrrolidinium, 1-ethyl-1-methylpyrrolidinium, 1-methyl-1-propylpyrrolidinium, 1-methyl-1-butylpyrrolidinium. 1-methyl-1-pentylpyrrolidinium, 1-methyl-1-hexylpyrrolidinium, 1-methyl-1-heptylpyrrolidinium, 1-methyl-1-octylpyrrolidinium, 1-methyl- 1-nonylpyrrolidinium, 1-methyl-1-decylpyrrolidinium, 1-methyl-1-methoxyethoxyethylpyrrolidinium, 1-ethyl-1-propylpyrrolidinium, 1-ethyl-1-butylpyrroli Dinium, 1-ethyl-1-pentylpyrrolidinium, 1-ethyl-1-hexylpyrrolidinium, 1-ethyl-1-heptylpyrrolidinium, 1,1-dipropylpyrrolidinium, 1-propyl- 1-butylpyrrolidinium, 1,1-dibutylpyrrolidinium, pyrrolidinium-2-one and the like can be mentioned.

Specific examples of the piperidinium cation include 1-propylpiperidinium, 1-pentylpiperidinium, 1,1-dimethylpiperidinium, 1-methyl-1-ethylpiperidinium, 1-methyl-1- Propylpiperidinium, 1-methyl-1-butylpiperidinium, 1-methyl-1-pentylpiperidinium, 1-methyl-1-hexylpiperidinium, 1-methyl-1-heptylpiperidinium, 1 -Methyl-1-octylpiperidinium, 1-methyl-1-decylpiperidinium, 1-methyl-1-methoxyethoxyethylpiperidinium, 1-ethyl-1-propylpiperidinium, 1-ethyl-1 -Butylpiperidinium, 1-ethyl-1-pentylpiperidinium, 1-ethyl-1-hexylpiperidinium, 1-ethyl-1-heptylpiperidinium, 1,1-dipropylpiperidinium, 1 -Propyl-1-butylpiperidinium, 1-propyl-1-pentylpiperidinium, 1-propyl-1-hexylpiperidinium, 1-propyl-1-heptylpiperidinium, 1,1-dibutylpiperidin And 1-butyl-1-pentylpiperidinium, 1-butyl-1-hexylpiperidinium, 1-butyl-1-heptylpiperidinium and the like.

Specific examples of the cation having a pyrroline skeleton include 2-methyl-1-pyrroline and the like. Specific examples of the cation having a pyrrole skeleton include 1-ethyl-2-phenylindole, 1,2-dimethylindole, 1-ethylcarbazole and the like.

Examples of the cation represented by the formula (B) include an imidazolium cation, a tetrahydropyrimidinium cation, and a dihydropyrimidinium cation.

Specific examples of the imidazolium cation include 1,3-dimethylimidazolium, 1,3-diethylimidazolium, 1-methyl-3-ethylimidazolium, 1-methyl-3-hexylimidazolium, 1-ethyl-3. -Methylimidazolium, 1-propyl-3-methylimidazolium, 1-butyl-3-methylimidazolium, 1-pentyl-3-methylimidazolium, 1-hexyl-3-methylimidazolium, 1-heptyl- 3-methylimidazolium, 1-octyl-3-methylimidazolium, 1-nonyl-3-methylimidazolium, 1-decyl-3-methylimidazolium, 1-dodecyl-3-methylimidazolium, 1-tetradecyl- 3-methylimidazolium, 1-hexadecyl-3-methylimidazolium, 1-octadecyl-3-methylimidazolium, 1,2-dimethyl-3-propylimidazolium, 1-ethyl-2,3-dimethylimidazolium, 1-butyl-2,3-dimethylimidazolium, 1-hexyl-2,3-dimethylimidazolium, 1-(2-methoxyethyl)-3-methylimidazolium and the like can be mentioned.

Specific examples of the tetrahydropyrimidinium cation include 1,3-dimethyl-1,4,5,6-tetrahydropyrimidinium and 1,2,3-trimethyl-1,4,5,6-tetrahydropyrimidinium. , 1,2,3,4-tetramethyl-1,4,5,6-tetrahydropyrimidinium, 1,2,3,5-tetramethyl-1,4,5,6-tetrahydropyrimidinium, etc. Can be mentioned.

Specific examples of the dihydropyrimidinium cation include 1,3-dimethyl-1,4-dihydropyrimidinium, 1,3-dimethyl-1,6-dihydropyrimidinium and 1,2,3-trimethyl-1. ,4-dihydropyrimidinium, 1,2,3-trimethyl-1,6-dihydropyrimidinium, 1,2,3,4-tetramethyl-1,4-dihydropyrimidinium, 1,2,3 , 4-tetramethyl-1,6-dihydropyrimidinium and the like.

Examples of the cation represented by the formula (C) include a pyrazolium cation and a pyrazolinium cation.

Specific examples of the pyrazolium cation include 1-methylpyrazolium, 3-methylpyrazolium, 1-ethyl-2,3,5-trimethylpyrazolium, 1-propyl-2,3,5-trimethyl. Examples thereof include pyrazolium, 1-butyl-2,3,5-trimethylpyrazolium, 1-(2-methoxyethyl)pyrazolium and the like. Specific examples of the pyrazolinium cation include 1-ethyl-2-methylpyrazolinium and the like.

Examples of the cation represented by the formula (D) include cations in which R ₁ , R _m , R _n, and R _o are the same or different and are all alkyl groups having 1 to 20 carbon atoms. Examples of such cations include tetraalkylammonium cations, trialkylsulfonium cations and tetraalkylphosphonium cations. Other examples of the cation represented by the formula (D) include those in which a part of the above alkyl group is substituted with an alkenyl group or an alkoxy group, and further an epoxy group. Further, one or more of R ₁ , R _m , R _n and R _o may contain an aromatic ring or an aliphatic ring.

The cation represented by the formula (D) may be a cation having a symmetrical structure or an asymmetric cation. Examples of the ammonium cation having a symmetrical structure include alkyl groups having the same R ₁ , R _m , R _n and R _o (for example, methyl group, ethyl group, propyl group, butyl group, pentyl group, hexyl group, heptyl group, octyl group). , Nonyl group, decyl group, dodecyl group, hexadecyl group, octadecyl group).

A typical example of the asymmetric ammonium cation is a tetraalkylammonium cation in which three of R ₁ , R _m , R _n, and R _o are the same and the other one is different, and specific examples are trimethylethylammonium and trimethylpropylammonium. , Trimethylbutylammonium, trimethylpentylammonium, trimethylhexylammonium, trimethylheptylammonium, trimethyloctylammonium, trimethylnonylammonium, trimethyldecylammonium, triethylmethylammonium, triethylpropylammonium, triethylbutylammonium, triethylpentylammonium, triethylhexylammonium, triethyl Heptyl ammonium, triethyl octyl ammonium, triethyl nonyl ammonium, triethyl decyl ammonium, tripropyl methyl ammonium, tripropyl ethyl ammonium, tripropyl butyl ammonium, tripropyl pentyl ammonium, tripropyl hexyl ammonium, tripropyl heptyl ammonium, tripropyl octyl ammonium, Tripropyl nonyl ammonium, tripropyl decyl ammonium, tributyl methyl ammonium, tributyl ethyl ammonium, tributyl propyl ammonium, tributyl pentyl ammonium, tributyl hexyl ammonium, tributyl heptyl ammonium, tripentyl methyl ammonium, tripentyl ethyl ammonium, tripentyl propyl ammonium, tri Pentylbutylammonium, Tripentylhexylammonium, Tripentylheptylammonium, Trihexylmethylammonium, Trihexylethylammonium, Trihexylpropylammonium, Trihexylbutylammonium, Trihexylpentylammonium, Trihexylheptylammonium, Triheptylmethylammonium, Trihexylbutylammonium Heptylethylammonium, triheptylpropylammonium, triheptylbutylammonium, triheptylpentylammonium, triheptylhexylammonium, trioctylmethylammonium, trioctylethylammonium, trioctylpropylammonium, trioctylbutylammonium, trioctylpentylammonium, trio Octyl hexyl Examples include asymmetric tetraalkylammonium cations such as ammonium, trioctylheptylammonium, trioctyldodecylammonium, trioctylhexadecylammonium, trioctyloctadecylammonium, trinonylmethylammonium, and tridecylmethylammonium.

Other examples of asymmetric ammonium cations include dimethyldiethylammonium, dimethyldipropylammonium, dimethyldibutylammonium, dimethyldipentylammonium, dimethyldihexylammonium, dimethyldiheptylammonium, dimethyldioctylammonium, dimethyldinonylammonium, dimethyldidecylammonium, Dipropyldiethylammonium, dipropyldibutylammonium, dipropyldipentylammonium, dipropyldihexylammonium, dimethylethylpropylammonium, dimethylethylbutylammonium, dimethylethylpentylammonium, dimethylethylhexylammonium, dimethylethylheptylammonium, dimethylethylnonylammonium, dimethyl Propylbutylammonium, dimethylpropylpentylammonium, dimethylpropylhexylammonium, dimethylpropylhexylammonium, dimethylbutylhexylammonium, dimethylbutylheptylammonium, dimethylpentylhexylammonium, dimethylhexylheptylammonium, diethylmethylpropylammonium, diethylmethylpentylammonium, diethyl Methylheptylammonium, diethylpropylpentylammonium, dipropylmethylethylammonium, dipropylmethylpentylammonium, dipropylbutylhexylammonium, dibutylmethylpentylammonium, dibutylmethylhexylammonium, methylethylpropylbutylammonium, methylethylpropylpentylammonium, methyl Tetraalkylammonium cations such as ethylpropylhexylammonium; ammonium cations containing cycloalkyl groups such as trimethylcyclohexylammonium; alkenyl groups such as diallyldimethylammonium, diallyldipropylammonium, diallylmethylhexylammonium and diallylmethyloctylammonium. Ammonium cations including; triethyl(methoxyethoxyethyl)ammonium, dimethylethyl(methoxyethoxyethyl)ammonium, dimethylethyl(ethoxyethoxyethyl)ammonium, diethylmethyl(2-methoxyethyl)ammonium, diethylmethyl(methoxyethoxyethyl)ammonium, etc. , Arcoki And an ammonium cation containing an epoxy group such as glycidyltrimethylammonium; and the like.

As the sulfonium cation having a symmetrical structure, a trialkylsulfonium cation in which R ₁ , R _m and R _n are the same alkyl group (for example, any of a methyl group, an ethyl group, a propyl group, a butyl group and a hexyl group) is used. It is illustrated. Examples of asymmetric sulfonium cations include asymmetric trialkylsulfonium cations such as dimethyldecylsulfonium, diethylmethylsulfonium and dibutylethylsulfonium.

Examples of the phosphonium cation having a symmetrical structure include alkyl groups having the same R ₁ , R _m , R _n and R _o (for example, methyl group, ethyl group, butyl group, pentyl group, hexyl group, heptyl group, octyl group, nonyl group). , Or a decyl group). The asymmetric phosphonium cation is a tetraalkylphosphonium cation in which three of R ₁ , R _m , R _n and R _o are the same and the other one is different, and specific examples thereof include trimethylpentylphosphonium, trimethylhexylphosphonium and trimethyl. Heptylphosphonium, trimethyloctylphosphonium, trimethylnonylphosphonium, trimethyldecylphosphonium, triethylmethylphosphonium, tributylethylphosphonium, tributyl-(2-methoxyethyl)phosphonium, tripentylmethylphosphonium, trihexylmethylphosphonium, triheptylmethylphosphonium, trioctyl Examples thereof include methylphosphonium, trinonylmethylphosphonium, tridecylmethylphosphonium and the like. Other examples of asymmetric phosphonium cations, such as trihexyl tetradecylphosphonium, dimethyldipentylphosphonium, dimethyldihexylphosphonium, dimethyldiheptylphosphonium, dimethyldioctylphosphonium, dimethyldinonylphosphonium, dimethyldidecylphosphonium, asymmetric tetraalkylphosphonium cations. A sulfonium cation containing an alkoxy group such as trimethyl(methoxyethoxyethyl)phosphonium and dimethylethyl(methoxyethoxyethyl)phosphonium.

Suitable examples of the cation represented by the formula (D) include the above-mentioned asymmetric tetraalkylammonium cation, asymmetric trialkylsulfonium cation and asymmetric tetraalkylphosphonium cation.

Examples of the cation represented by the formula (E) include a sulfonium cation in which R _p is an alkyl group having 1 to 18 carbon atoms. Specific examples of R _p include a methyl group, an ethyl group, a propyl group, a butyl group, a hexyl group, an octyl group, a nonyl group, a decyl group, a dodecyl group, a tridecyl group, a tetradecyl group and an octadecyl group.

The anion component of the ionic liquid is not particularly limited as long as it can form a salt with any of the cations disclosed herein into an ionic liquid. Specific examples include Cl ⁻ , Br ⁻ , I ⁻ , AlCl ₄ ⁻ , Al ₂ Cl ₇ ⁻ , BF ₄ ⁻ , PF ₆ ⁻ , ClO ₄ ⁻ , NO ₃ ⁻ , CH ₃ COO ⁻ , CF ₃ COO ⁻ , CH ₃ SO ₃ ⁻ , CF ₃ SO ₃ ⁻ , (FSO ₂ ) ₂ N ⁻ , (CF ₃ SO ₂ ) ₂ N ⁻ , (CF ₃ SO ₂ ) ₃ C ⁻ , AsF ₆ ⁻ , SbF ₆ ⁻ , NbF ₆ ⁻ , TaF ₆ ⁻ , F(HF) _n ⁻ , (CN) ₂ N ⁻ , C ₄ F ₉ SO ₃ ⁻ , (C ₂ F ₅ SO ₂ ) ₂ N ⁻ , C ₃ F ₇ COO ⁻ , (CF _{3 ).} SO ₂ )(CF ₃ CO)N ⁻ , C ₉ H ₁₉ COO ⁻ , (CH ₃ ) ₂ PO ₄ ⁻ , (C ₂ H ₅ ) ₂ PO ₄ ⁻ , C ₂ H ₅ OSO ₃ ⁻ , C ₆ H ₁₃ OSO ₃ ⁻ , C ₈ H ₁₇ OSO ₃ ⁻ , CH ₃ (OC ₂ H ₄ ) ₂ OSO ₃ ⁻ , C ₆ H ₄ (CH ₃ )SO ₃ ⁻ , (C ₂ F ₅ ) ₃ PF ₃ ⁻ , CH ₃ Examples thereof include CH(OH)COO ⁻ and anions represented by the following formula (F).

Among them, the hydrophobic anion component tends not to bleed on the pressure-sensitive adhesive surface, and is preferably used from the viewpoint of low stain resistance. An anion component containing a fluorine atom (for example, an anion component containing a perfluoroalkyl group) is preferably used because an ionic compound having a low melting point can be obtained. Suitable examples of the anion component include bis(perfluoroalkylsulfonyl)imide anion (eg (CF ₃ SO ₂ ) ₂ N ⁻ , (C ₂ F ₅ SO ₂ ) ₂ N ⁻ ) and perfluoroalkylsulfonium anion (eg, , CF ₃ SO ₃ ⁻ ) and the like. The number of carbon atoms of the perfluoroalkyl group is usually preferably 1 to 3, and more preferably 1 or 2.

The ionic liquid used in the technology disclosed herein may be an appropriate combination of the above cation component and anion component. As an example, when the cation component is a pyridinium cation, specific combinations with the above-mentioned anion component include 1-butylpyridinium tetrafluoroborate, 1-butylpyridinium hexafluorophosphate, 1-butyl-3-methylpyridinium tetra Fluoroborate, 1-butyl-3-methylpyridinium trifluoromethanesulfonate, 1-butyl-3-methylpyridinium bis(trifluoromethanesulfonyl)imide, 1-butyl-3-methylpyridinium bis(pentafluoroethanesulfonyl)imide, 1- Hexylpyridinium tetrafluoroborate, 1-allylpyridinium bis(trifluoromethanesulfonyl)imide and the like can be mentioned. Similarly, for each of the other cations described above, an ionic liquid in combination with any of the anion components disclosed herein can be used.

As such an ionic liquid, a commercially available one can be used, or it can be easily synthesized by a known method. The method of synthesizing the ionic liquid is not particularly limited as long as the desired ionic liquid can be obtained. Generally, the halide method, the hydroxide method, the acid ester method, the complex formation method as described in the publicly known document "Ionic liquids-Frontiers of development and future-" (published by CMC Publishing Co., Ltd.) , And a neutralization method are used.

(Other ionic compounds)
As the ionic compound, in addition to the above-mentioned alkali metal salts and ionic liquids (eg organic cation-anion salts), inorganic compounds such as ammonium chloride, aluminum chloride, copper chloride, ferrous chloride, ferric chloride, ammonium sulfate, etc. Salt can also be used. The ionic compounds disclosed herein also include those generally referred to as ionic surfactants. As the ionic surfactant, a cationic surfactant having a cationic functional group such as quaternary ammonium salt, phosphonium salt, sulfonium salt, pyridinium salt and amino group; carboxylic acid, sulfonate, sulfate, phosphate, phosphite, etc. An anionic surfactant having an anionic functional group; a zwitterionic surfactant such as sulfobetaine and its derivative, alkylbetaine and its derivative, imidazoline and its derivative, alkylimidazolium betaine and its derivative; and the like. .. These may be used alone or in combination of two or more.

The amount of the ionic compound contained in the pressure-sensitive adhesive layer is not particularly limited, and can be about 1% by weight or more in the pressure-sensitive adhesive layer (in the solid content of the pressure-sensitive adhesive composition), and from the viewpoint of improving conductivity. It is suitable to be about 3% by weight or more, preferably about 6% by weight or more, more preferably about 9% by weight or more, further preferably about 12% by weight or more. The amount of the ionic compound in the pressure-sensitive adhesive layer is usually about 40% by weight or less, and from the viewpoint of the influence on the adhesive property and the prevention of contamination of the adherend, about 30% by weight or less is suitable, and preferably about 30% by weight. It is 25% by weight or less (for example, about 20% by weight or less).

The pressure-sensitive adhesive layer disclosed herein is, as a conductive agent, an organic conductive substance such as polythiophene, polyaniline, polypyrrole, polyethyleneimine, and an allylamine-based polymer, tin oxide, antimony oxide, indium oxide, cadmium oxide, and oxide. Titanium, zinc oxide, indium, tin, antimony, gold, silver, copper, aluminum, nickel, chromium, titanium, iron, cobalt, copper iodide, ITO (indium oxide/tin oxide), ATO (antimony oxide/tin oxide) Inorganic conductive substances such as metal particles and metal oxide particles may be contained. As the conductive agent, an inorganic composite conductive material in which inorganic particles such as glass are coated with a metal such as silver, or an organic-inorganic composite conductive material in which inorganic particles are coated with an organic material such as a conductive polymer can also be used. The content of a conductive substance other than such an ionic compound (typically, an inorganic conductive substance) is a pressure-sensitive adhesive from the viewpoint of compatibility between adhesive force and adherence/separation removability, transparency, and the like. Suitably, it is limited to less than 20% by volume in the layer, preferably less than 10% by volume, more preferably less than 3% by volume and even more preferably less than 1% by volume. The technique disclosed herein can be preferably implemented in a mode in which the pressure-sensitive adhesive layer does not substantially contain a conductive substance other than the ionic compound.

In the technology disclosed herein, the form of the pressure-sensitive adhesive composition used for forming the pressure-sensitive adhesive layer is not particularly limited. For example, a pressure-sensitive adhesive composition containing a pressure-sensitive adhesive component in an organic solvent (solvent-type pressure-sensitive adhesive composition), a pressure-sensitive adhesive composition in which a pressure-sensitive adhesive component is dispersed in an aqueous solvent (water-dispersed pressure-sensitive adhesive composition, typically Is an aqueous emulsion-type pressure-sensitive adhesive composition), a pressure-sensitive adhesive composition in which the pressure-sensitive adhesive component is dissolved in water (aqueous-type pressure-sensitive adhesive composition), a solventless pressure-sensitive adhesive composition (for example, ultraviolet rays, electron beams, etc. It can be a pressure-sensitive adhesive composition of a type that cures upon irradiation with various active energy rays, a hot-melt pressure-sensitive adhesive composition), or the like. In some preferred embodiments, the pressure-sensitive adhesive sheet includes a pressure-sensitive adhesive layer formed from the solvent-based pressure-sensitive adhesive composition. The organic solvent contained in the solvent-based pressure-sensitive adhesive composition may be, for example, a single solvent composed of any of toluene, xylene, ethyl acetate, hexane, cyclohexane, methylcyclohexane, heptane and isopropyl alcohol, and any of these. It may be a mixed solvent containing as a main component.

In the technology disclosed herein, a pressure-sensitive adhesive composition (preferably a solvent-type pressure-sensitive adhesive composition) used for forming a pressure-sensitive adhesive layer is a polymer (typically an oxyalkylene structure) contained in the composition. A polymer configured so that the unit-containing polymer) can be appropriately crosslinked can be preferably used. As a specific cross-linking means, a cross-linking point is introduced into the above polymer by copolymerizing a monomer having an appropriate functional group (hydroxyl group, carboxyl group, etc.), and the cross-linking structure is formed by reacting with the functional group. A method in which a compound (crosslinking agent) capable of reacting is added to the above polymer and reacted is preferably employed.

The type of crosslinking agent used is not particularly limited, and examples thereof include isocyanate crosslinking agents, epoxy crosslinking agents, oxazoline crosslinking agents, aziridine crosslinking agents, melamine crosslinking agents, peroxide crosslinking agents, urea crosslinking agents. , A metal alkoxide-based crosslinking agent, a metal chelate-based crosslinking agent, a metal salt-based crosslinking agent, a carbodiimide-based crosslinking agent, an amine-based crosslinking agent, and the like. These cross-linking agents can be used alone or in combination of two or more. Of these, isocyanate crosslinking agents are preferable.

The amount of the cross-linking agent used can be appropriately selected according to the type and structure of the polymer, the molecular weight, etc., and the adhesive properties such as adhesive strength and releasability. For example, when the amount of the cross-linking agent used is a predetermined amount or more, the cohesive force of the pressure-sensitive adhesive is improved, and adhesive residue on the adherend can be prevented. From such a viewpoint, it is appropriate that the amount of the cross-linking agent used is about 0.01 parts by weight or more based on 100 parts by weight of the polymer (typically an oxyalkylene structural unit-containing polymer), and preferably about 0. It is 1 part by weight or more (for example, about 0.2 parts by weight or more). The amount of the crosslinking agent used is preferably about 10 parts by weight or less (for example, about 5 parts by weight or less). In an embodiment in which an isocyanate-based crosslinking agent is used as the crosslinking agent, the amount of the isocyanate-based crosslinking agent used is approximately 0.5 parts by weight or more based on 100 parts by weight of the polymer (typically an oxyalkylene structural unit-containing polymer). It is suitable, preferably about 1 part by weight or more, more preferably about 1.5 parts by weight or more (for example, about 2 parts by weight or more), and about 3 parts by weight or less.

The above-mentioned pressure-sensitive adhesive composition may further contain a catalyst for the purpose of promoting various reactions relating to the formation of the pressure-sensitive adhesive layer. Such a catalyst may be what is called a crosslinking catalyst or a curing catalyst. The type of catalyst can be appropriately selected according to the type of compound (crosslinking agent, etc.) used. Examples of the catalyst include iron acetylacetonate, iron-containing compounds such as iron 2-ethylhexanoate, dioctyltin dilaurate, dibutyltin dilaurate, dibutyltin diacetylate, dibutyltin diacetylacetonate, and tetra-n-butyltin. , Tin (Sn)-containing compounds such as trimethyltin hydroxide, titanium-containing compounds such as tetraisopropyl titanate and tetra-n-butyl titanate; organometallic compounds such as; N,N,N′,N′-tetramethylhexanediamine , Amines such as triethylamine, nitrogen (N)-containing compounds such as imidazoles; basic compounds such as lithium hydroxide, potassium hydroxide and sodium methylate; p-toluenesulfonic acid, trichloroacetic acid, phosphoric acid, monoalkylphosphorus Acid, dialkyl phosphoric acid, acidic compounds such as phosphoric acid ester of β-hydroxyethyl acrylate; and the like are exemplified. These may be used alone or in combination of two or more. The amount of the catalyst contained in the pressure-sensitive adhesive composition may be, for example, about 0.001 to 10 parts by weight (preferably about 0.005 to 5 parts by weight) with respect to 100 parts by weight of the polymer.

The technology disclosed herein can also be implemented in an embodiment using a pressure-sensitive adhesive layer containing a polymer different from an oxyalkylene structural unit-containing polymer (that is, a polymer not containing an oxyalkylene structural unit). In the embodiment in which the pressure-sensitive adhesive layer contains the oxyalkylene structural unit-containing polymer, the above oxyalkylene structural unit-free polymer may be included in addition to the oxyalkylene structural unit-containing polymer. As the oxyalkylene structural unit-free polymer, various polymers exemplified above, which do not have an oxyalkylene structural unit, can be used. The content of the oxyalkylene structural unit-free polymer in the pressure-sensitive adhesive layer is set according to the target pressure-sensitive adhesive property and conductivity, and is not limited to a specific range. For example, in the pressure-sensitive adhesive layer (in the solid content of the pressure-sensitive adhesive composition), the content can be about 70% by weight or less, and about 50% by weight or less is suitable. From the viewpoint of sufficiently exerting the action of the layer constituent components, it is preferably about 30% by weight or less, more preferably about 10% by weight or less, and further preferably about 3% by weight or less (for example, 0 to 1% by weight).

If desired, various conventionally known additives can be further added to the pressure-sensitive adhesive composition. Examples of such additives include surface lubricants, leveling agents, antioxidants, preservatives, light stabilizers, ultraviolet absorbers, polymerization inhibitors, silane coupling agents and the like. In addition, a tackifying resin and a peel control agent may be blended. Further, the pressure-sensitive adhesive layer disclosed herein may or may not contain an alkylene oxide compound such as polyethylene glycol or polypropylene glycol. When the tacky polymer is synthesized by the emulsion polymerization method, an emulsifier or a chain transfer agent (which can be understood as a molecular weight modifier or a polymerization degree modifier) is preferably used.

(Method for forming adhesive layer)
The pressure-sensitive adhesive layer in the technology disclosed herein can be formed by, for example, a method (direct method) of directly applying the pressure-sensitive adhesive composition as described above to a base film and drying or curing the same. Alternatively, it is also possible to form the pressure-sensitive adhesive layer on the surface of the release liner by applying the pressure-sensitive adhesive composition to the surface (release surface) of the release liner and then drying or curing it. It may be formed by a method of transferring the pressure-sensitive adhesive layer by bonding the agent layer to a substrate film (transfer method). From the viewpoint of anchoring property of the pressure-sensitive adhesive layer, usually, the direct method can be preferably adopted. When applying (typically applying) the pressure-sensitive adhesive composition, adhesion such as roll coating method, gravure coating method, reverse coating method, roll brush method, spray coating method, air knife coating method, coating method using a die coater, etc. Various conventionally known methods in the field of sheets can be appropriately adopted. The pressure-sensitive adhesive composition can be dried, if necessary, under heating (for example, by heating at about 60° C. to 150° C.). As a means for curing the pressure-sensitive adhesive composition, ultraviolet rays, laser rays, α rays, β rays, γ rays, X rays, electron rays and the like can be appropriately adopted.

(Thickness of adhesive layer)
Although not particularly limited, the thickness of the pressure-sensitive adhesive layer can be, for example, about 1 μm or more, and from the viewpoint of adhesion reliability with respect to the adherend, it is suitable to be about 3 μm or more, and preferably It is about 5 μm or more (for example, about 7 μm or more). The above-mentioned thickness can be, for example, about 100 μm or less, and from the viewpoint of adherend separation removability, it is suitable to be about 50 μm or less, and preferably about 30 μm or less (for example, about 20 μm or less). is there. Since the pressure-sensitive adhesive layer disclosed herein can exhibit good conductivity without using a conductive agent such as metal particles, a pressure-sensitive adhesive layer showing a surface resistance value of a predetermined value or less is formed in a relatively thin thickness. can do.

<Adhesive composition>
As described above, the pressure-sensitive adhesive layer included in the pressure-sensitive adhesive sheet disclosed herein is formed from the pressure-sensitive adhesive composition. Therefore, the technology disclosed herein includes an adhesive composition. According to the above-mentioned pressure-sensitive adhesive composition, it is possible to achieve both a predetermined electric conductivity and a predetermined range of adhesive force, and for example, has a surface resistance value of 1.0×10 ⁸ Ω/□ or less, and a SUS plate. A pressure-sensitive adhesive having a pressure-sensitive adhesive strength within the range of 0.01 to 4.0 N/20 mm can be preferably realized. The PSA composition disclosed herein may contain an oxyalkylene structural unit as described above. The pressure-sensitive adhesive composition according to some preferred embodiments contains a polymer having an oxyalkylene structural unit and/or an oligomer or a monomer for forming the polymer, and further contains an ionic compound and various additive components as optional components. obtain. The details of the composition (specific examples and contents of the contained components) are as described above, and therefore the description will not be repeated.

<Base material layer>
In the pressure-sensitive adhesive sheet with a substrate of the single-sided pressure-sensitive adhesive type or the double-sided pressure-sensitive adhesive type, various substrate films can be used as the substrate layer for supporting (lining) the pressure-sensitive adhesive layer. As the substrate film, a resin film, paper, cloth, rubber sheet, foam sheet, metal foil, composite of these, or the like can be used. Especially, a resin film can be preferably used. The resin film here is typically a non-porous resin sheet, and is a concept that is distinguished from, for example, non-woven fabric (that is, does not include non-woven fabric), and usually various resin materials are formed into a film shape. It is molded into.

Examples of the resin film include polyolefin resin films such as polyethylene (PE), polypropylene (PP) and ethylene/propylene copolymer; polyester resin films such as polyethylene terephthalate (PET) and polyethylene naphthalate (PEN); Vinyl resin films; vinyl acetate resin films; polyimide resin films; polyamide resin films; fluororesin films; cellophane; and the like. The resin film may have a single-layer structure or a structure in which a plurality of layers having different compositions are laminated. Usually, a resin film having a single layer structure can be preferably used.

Examples of paper include Japanese paper, kraft paper, glassine paper, high-quality paper, synthetic paper, and top-coated paper. Examples of the cloth include woven cloth and non-woven cloth made of various fibrous substances alone or mixed. Examples of the fibrous substance include cotton, staple fiber, Manila hemp, pulp, rayon, acetate fiber, polyester fiber, polyvinyl alcohol fiber, polyamide fiber, and polyolefin fiber. Examples of the rubber sheet include a natural rubber sheet and a butyl rubber sheet. Examples of foam sheets include foamed polyurethane sheets and foamed polychloroprene rubber sheets. Examples of the metal foil include aluminum foil and copper foil.

The elastic modulus of the base film (typically a resin film) constituting the base layer is not particularly limited, and is about 50 MPa or more from the viewpoint of having a predetermined rigidity and stably supporting an adherend. It is appropriate to have. Further, from the viewpoint of the bonding property and the handling property, it is suitable that the elastic modulus is about 50,000 MPa or less. The elastic modulus of the base film can be set by selecting an optimal material so as to have predetermined rigidity and flexibility according to the purpose of use. In some embodiments, the elastic modulus of the substrate film (eg, soft vinyl chloride resin film) is about 100 MPa or more (typically about 150 MPa or more, such as about 200 MPa or more), and about 1,000 MPa or less (typically Of about 600 MPa or less, for example, about 300 MPa or less). In some other embodiments, the elastic modulus of the substrate film (eg, olefin-based resin film) is about 300 MPa or more (typically 400 MPa or more) and about 10,000 MPa or less (typically 3,000 MPa). Hereinafter, for example, 1,000 MPa or less). In some other embodiments, the elastic modulus of the substrate film (eg, polyester resin film) is about 500 MPa or more (typically 1,000 MPa or more, eg, 3,000 MPa or more), and about 30,000 MPa. Or less (typically 15,000 MPa or less, for example 7,000 MPa or less).

The elastic modulus of the base material film (typically a resin film) is in any one direction from the resin film (for example, MD (Machine Direction) or TD (Transverse Direction; direction orthogonal to MD), preferably MD). A test piece of a predetermined width was cut out along with, and in accordance with JIS K7161, at room temperature (23°C), the test piece was stretched in one direction at a tensile speed of 300 mm/min to obtain a stress-strain curve. It is a tensile modulus calculated from linear regression.

As the above-mentioned base film (typically, a resin film), a transparent film is preferably used from the viewpoint of the inspection property through the adhesive sheet. Therefore, it is preferable that the resin film has transparency such that the total light transmittance in the visible light wavelength region is about 70% or more. A transparent resin film having a total light transmittance of 80% or more (for example, 85% or more) is more preferable. The upper limit of the total light transmittance is ideally 100%, but as long as it has a total light transmittance of about 99% or less (typically 97% or less, for example, 95% or less), In practice, it can be preferably used as a transparent resin film. As the value of the total light transmittance, a notarized value by the manufacturer can be adopted. If there is no notarized value, the value measured according to JIS K 7361-1 can be adopted.

If necessary, the base material layer may contain various additives such as a filler, an antioxidant, an ultraviolet absorber, an antistatic component, a plasticizer, a lubricant, and a coloring agent (pigment, dye, etc.). Good. The pressure-sensitive adhesive layer side surface of the base material layer may be subjected to a known or common surface treatment such as corona discharge treatment, plasma treatment, ultraviolet irradiation treatment, acid treatment, alkali treatment, and application of an undercoat agent. Good. Such surface treatment may be, for example, a treatment for improving the anchoring property of the pressure-sensitive adhesive layer. In addition, when the surface of the pressure-sensitive adhesive layer is brought into contact with the back surface of the base material layer by winding the single-sided pressure-sensitive adhesive sheet, the back surface of the base material layer (the surface opposite to the surface where the pressure-sensitive adhesive layer is provided) In addition, if necessary, a release treatment with a release agent such as a silicone type, a long-chain alkyl type, or a fluorine type may be applied. By performing the peeling treatment, it is possible to obtain effects such as easy rewinding of the wound body obtained by winding the pressure-sensitive adhesive sheet in a roll shape.

The thickness of the base material layer can be appropriately selected in consideration of the application, purpose, usage form of the adhesive sheet. From the viewpoint of workability such as strength and handleability, a substrate film having a thickness of about 10 μm or more is usually suitable, preferably about 15 μm or more, more preferably about 20 μm or more, further preferably 30 μm or more (for example, 35 μm or more). Is. Further, the thickness of the base material layer is usually about 1 mm or less, about 200 μm or less is appropriate, preferably about 150 μm or less, more preferably about 100 μm or less, and further preferably from the viewpoint of cost and inspectability. It is about 75 μm or less.

<Undercoat layer>
In some embodiments, an undercoat layer is provided on the pressure-sensitive adhesive layer side surface of the base material layer. In other words, the undercoat layer is arranged between the base material layer and the pressure-sensitive adhesive layer. The undercoat layer may have a single layer structure or a multilayer structure of two or more layers. The material (undercoating agent) for forming the undercoat layer is not particularly limited, and urethane resin, polyester resin, acrylic resin, acryl-urethane resin, acryl-styrene resin, polyamide resin, melamine resin, One or more kinds of olefin resin, polystyrene resin, epoxy resin, phenol resin, isocyanurate resin, polyvinyl acetate resin, etc. may be used. When an acrylic-based pressure-sensitive adhesive layer is provided on a resin film substrate, a polyester-based, urethane-based, or acrylic-based undercoating agent is preferred. When an acrylic-based pressure-sensitive adhesive layer is provided on a polyester-based substrate layer such as PET film, A polyester-based undercoat layer is particularly preferable.

<Conductive undercoat layer>
In some preferred embodiments, the undercoat layer disposed between the base material layer and the pressure-sensitive adhesive layer preferably contains a conductive agent. This improves the conductivity of the pressure-sensitive adhesive sheet and improves the electrical conductivity of the adherend. Hereinafter, the undercoat layer containing a conductive agent is also referred to as a conductive undercoat layer. The conductive undercoat layer may have a single layer structure or a multilayer structure of two or more layers. In the embodiment in which the undercoat layer having a multi-layer structure is arranged between the base material layer and the pressure-sensitive adhesive layer, at least one layer (typically at least one layer including the layer in contact with the pressure-sensitive adhesive layer) is a conductive undercoat layer. It is preferable that As the conductive agent, polythiophene, polyaniline, polypyrrole, polyethyleneimine, organic conductive substances such as allylamine-based polymers, gold, silver, copper, platinum, palladium, aluminum, nickel, chromium, titanium, iron, cobalt, tin, Metals such as magnesium and tungsten, alloys of these metals, metal oxides of indium, tin, zinc, gallium, antimony, zirconium and cadmium (tin oxide, antimony oxide, indium oxide, cadmium oxide, titanium oxide, zinc oxide, Inorganic conductive substances such as metal particles of ITO (indium oxide/tin oxide), ATO (antimony oxide/tin oxide), copper iodide, metal oxide particles, metal compound particles, etc. can be used. It is also possible to use an inorganic composite conductive material obtained by coating inorganic particles such as silver with a metal such as silver, or an organic-inorganic composite conductive material obtained by coating inorganic particles with an organic material such as a conductive polymer. These can be used alone or in combination of two or more.

In the embodiment in which the undercoat layer is arranged, examples of the conductive polymer that can be contained in the undercoat layer include polythiophene and polyaniline. As the polythiophene, one having a polystyrene-converted Mw of 40×10 ⁴ or less is preferable, and 30×10 ⁴ or less is more preferable. The polyaniline preferably has an Mw of 50×10 ⁴ or less, more preferably 30×10 ⁴ or less. The Mw of these conductive polymers is usually preferably 0.1×10 ⁴ or more, more preferably 0.5×10 ⁴ or more. In addition, in this specification, polythiophene refers to a polymer of unsubstituted or substituted thiophene. One preferred example of the substituted thiophene polymer in the technology disclosed herein is poly(3,4-ethylenedioxythiophene).

In some preferred embodiments, the conductive undercoat layer can include polystyrene sulfonate (PSS) as a dopant (eg, a thiophene-based polymer dopant). In some embodiments, the conductive undercoat layer is formed using a composition for forming an undercoat layer, which comprises a polythiophene aqueous solution containing PSS (which may be a form in which PSS is added to polythiophene as a dopant). Such an aqueous solution may contain polythiophene:PSS in a weight ratio of 1:1 to 1:10. The total content of polythiophene and PSS in the aqueous solution may be, for example, about 1 to 5% by weight. When using a polythiophene aqueous solution containing PSS, the total amount of polythiophene and PSS should be 5 parts by weight or more (usually 10 parts by weight or more, for example 25 parts by weight or more) with respect to 100 parts by weight of the binder. Is suitable, and preferably 40 parts by weight or more. The total amount of the polythiophene and PSS is appropriately 200 parts by weight or less, preferably 120 parts by weight or less (for example, 100 parts by weight or less), or 80 parts by weight, relative to 100 parts by weight of the binder. It may be part or less (for example, 60 parts by weight or less).

The amount of the organic conductive substance (typically, a conductive polymer) used can be about 10 parts by weight or more based on 100 parts by weight of the binder contained in the undercoat layer from the viewpoint of improving the conductivity, Is appropriately 25 parts by weight or more, preferably 40 parts by weight or more. Considering the compatibility of the organic electroconductive substance (typically the electroconductive polymer) in the undercoat layer and the change in properties such as the decrease in transparency due to the decrease in the compatibility, the organic electroconductive substance (typically the electroconductive polymer). It is suitable to use 200 parts by weight or less (for example, 150 parts by weight or less), and preferably 120 parts by weight or less (for example, 100 parts by weight or less) with respect to 100 parts by weight of the binder. The amount of the organic conductive substance (typically a conductive polymer) used may be 80 parts by weight or less (for example, 60 parts by weight or less) with respect to 100 parts by weight of the binder.

The total amount of the conductive agent in the conductive undercoat layer (the total amount of all the conductive agent including the organic conductive material, the inorganic conductive material and the organic-inorganic composite conductive material) is, depending on the desired conductivity, in the undercoat layer, The amount can be about 5% by weight (for example, about 10% by weight or more), and it is suitable that the amount is about 30% by weight or more. For example, it may exceed 50% by weight. The upper limit of the total amount of the conductive agent in the conductive undercoat layer is not particularly limited, and is appropriately about 90% by weight or less (for example, 80% by weight or less), and the adhesiveness to the base material layer or the pressure-sensitive adhesive layer, and the transparency. It may be about 40% by weight or less (for example, about 30% by weight or less) in consideration of the properties.

The conductive undercoat layer may contain a binder in addition to the above-mentioned conductive agent. As the binder that can be included in the conductive undercoat layer, the above-mentioned undercoat layer forming material (undercoat agent) can be used without particular limitation. Above all, it is preferable to use a polyester resin. The proportion of the binder in the entire conductive undercoat layer can be, for example, about 30% by weight or more, and is appropriately about 40% by weight or more (eg, about 50% by weight or more). Further, the proportion of the binder is appropriately less than 90% by weight (less than 80% by weight) in consideration of conductivity and the like.

Also, in some embodiments, the subbing layer contains a crosslinking agent. As the cross-linking agent, a melamine-based, isocyanate-based, or epoxy-based cross-linking agent that is commonly used for cross-linking resins can be appropriately selected and used. Thereby, the anchoring property to the base material layer and the adhesiveness to the pressure-sensitive adhesive layer can be preferably made compatible with each other. In some preferred embodiments, the crosslinker comprises a melamine-based crosslinker.

The undercoat layer is, if necessary, an antioxidant, a colorant (pigment, dye, etc.), a fluidity modifier (thixotropic agent, thickener, etc.), a film-forming aid, a surfactant (antifoaming agent, dispersion). Agents, etc.), and preservatives and other additives.

For the undercoat layer, a liquid composition (coating material for forming the undercoat layer) in which the above resin components and additives used as necessary are dispersed or dissolved in an appropriate solvent is used in a known method such as a gravure roll coater and a reverse roll coater. Alternatively, it can be suitably formed by a method including applying it to a base film using a conventional coater and, if necessary, drying and curing. From the viewpoint of forming a thin and uniform layer, the NV (nonvolatile content) of the coating material can be, for example, 5% by weight or less (typically 0.05 to 5% by weight). As the solvent that can constitute the coating material, any of an organic solvent, water, or a mixed solvent thereof can be used, and water or a mixed solvent containing water as a main component (for example, a mixed solvent of water and ethanol) can be used. preferable.

In some other aspects, the conductive undercoat layer can be, for example, a layer composed of the metals and metal oxides described above. As the conductive undercoat layer in this embodiment, a metal layer such as silver or aluminum is preferable from the viewpoint of conductivity, and an ITO layer or an ATO layer is preferable from the viewpoint of transparency. As ITO, those containing about 80 to 99% by weight of indium oxide and about 1 to 20% by weight of tin oxide are preferably used. The metal layer or the metal oxide layer as the conductive undercoat layer may be a metal vapor deposition layer of aluminum or the like, a plating layer, or the like.

The thickness of the undercoat layer in the technique disclosed herein is not particularly limited and is usually about 0.01 μm or more, and from the viewpoint of suitably expressing the function of the undercoat layer, it is suitable to be about 0.05 μm or more. And preferably about 0.1 μm or more (for example, about 0.2 μm or more). The upper limit of the thickness of the undercoat layer can be about 50 μm or less (for example, about 10 μm or less), and from the viewpoint of transparency or the like, about 3 μm or less is suitable, and preferably about 1 μm or less (eg, about 1 μm or less About 0.6 μm or less).

<Release liner>
The pressure-sensitive adhesive sheet disclosed herein is a form in which a release liner is bonded to the pressure-sensitive adhesive surface for the purpose of protecting the pressure-sensitive adhesive surface (the surface of the pressure-sensitive adhesive layer that is attached to the adherend). (Form of pressure-sensitive adhesive sheet with release liner). The release liner is not particularly limited, for example, a release liner in which the surface of a liner substrate such as a resin film or paper is release-treated, a fluoropolymer (polytetrafluoroethylene, etc.), a polyolefin resin (polyethylene, polypropylene, etc.). A release liner or the like made of the low-adhesion material of 1) can be used. For the release treatment, for example, a silicone-based, fluorine-based, long-chain alkyl-based, fatty acid amide-based release treatment agent, silica powder, or the like can be used. In some embodiments, release treated resin films (eg polyester films) may be preferably employed as the release liner. The thickness of the release liner can be, for example, about 5 μm to 200 μm, and normally about 10 μm to 100 μm is preferable.

<Total thickness of adhesive sheet>
The total thickness of the pressure-sensitive adhesive sheet disclosed herein (which may include the pressure-sensitive adhesive layer, the base material layer and the undercoat layer, but does not include the release liner) is not particularly limited and may be in the range of about 5 to 1000 μm. Appropriate. The total thickness of the adhesive sheet is preferably about 10 to 500 μm (for example, 15 to 300 μm, typically 20 to 200 μm) in consideration of adhesive properties and the like. From the viewpoint of handleability, it is appropriate that the total thickness of the pressure-sensitive adhesive sheet is about 30 μm or more, and about 150 μm or less (for example, 120 μm or less), and even about 80 μm or less. Good.

<Characteristics of adhesive sheet>
A pressure-sensitive adhesive sheet according to some typical embodiments has a 180-degree peel strength (adhesive strength. SUS plate against a stainless steel plate measured under conditions of a peel angle of 180 degrees and a speed of 300 mm/min in an environment of 23° C.). The adhesive strength) is characterized by being in the range of approximately 0.01 to 4.0 N/20 mm. According to the pressure-sensitive adhesive sheet exhibiting an adhesive strength within the above-mentioned predetermined range, it is possible to fix an adherend such as a conductive piece with good adhesion reliability, and after use, it can be satisfactorily separated from the adherend. It can prevent body damage. From the viewpoint of adhesion reliability, the adhesive force may be about 0.02 N/20 mm or more, about 0.03 N/20 mm or more, about 0.05 N/20 mm or more, or about 0.08 N/20 mm or more. Good. From the viewpoint of the ability to separate and remove the adherend, the adhesive force is suitably less than 3.0 N/20 mm (typically less than 2.0 N/20 mm, for example less than 1.0 N/20 mm), and preferably approximately It is 0.5 N/20 mm or less (typically less than 0.5 N/20 mm, for example less than 0.3 N/20 mm). The adhesive force to the SUS plate is measured by the method described in Examples below. The pressure-sensitive adhesive sheet disclosed in the present specification includes modes in which the above-mentioned pressure-sensitive adhesive force is not limited, and in such a mode, the pressure-sensitive adhesive sheet is not limited to those having the above-mentioned pressure-sensitive adhesive force.

The haze value of the adhesive sheet is not particularly limited and may be, for example, about 80% or less. When an adherend is inspected through an adhesive sheet, the adhesive sheet needs to have appropriate transparency. From such a viewpoint, the haze value of the pressure-sensitive adhesive sheet is appropriately about 50% or less (for example, about 30% or less), preferably about 10% or less, more preferably about 3% or less, and further preferably about It is 1% or less (for example, less than 0.1%). The haze value is measured by the method described in Examples below.

<Use>
The application of the pressure-sensitive adhesive sheet disclosed herein is not particularly limited, and it is adhered to an adherend by utilizing the adhesion reliability at the time of adhesion and good removability of adherend, and then peeled off. It can be widely used for various purposes. Examples of such applications include temporary fixing sheets and protective sheets. Further, for example, it can be preferably used as a process material which is fixed to an adherend and peeled off in the manufacturing process of electronic devices and electronic parts.

The pressure-sensitive adhesive sheet disclosed herein can be used as a conductive pressure-sensitive adhesive sheet for various purposes because the surface resistance value of the pressure-sensitive adhesive layer is limited to a predetermined value or less. For example, it can be preferably used as a conductive adhesive member in various electronic devices. The conductive pressure-sensitive adhesive sheet can be used for electromagnetic wave shielding of electronic devices, cables, etc., antistatic applications, etc.

The pressure-sensitive adhesive sheet according to some preferred embodiments can be used as a pressure-sensitive adhesive sheet that detachably holds a plurality of conductive pieces. The conductive small piece here is a metal chip, a semiconductor chip, an organic conductive chip, or the like used in various applications. For example, a light-emitting semiconductor chip (typically an LED chip) used in an electronic product with a display function, or the like. It may be a semiconductor chip. The number of conductive pieces arranged on one pressure-sensitive adhesive sheet is 1 or 2 or more, and in some aspects, the conductive pieces are a large number (for example, 10 or more, further, 10 or more, formed by dicing of a conductive wafer). 100 or more, 1000 or more, 10,000 or more, 100,000 or more). The size of each piece is not particularly limited, and may be, for example, a size of about 4 to 5 mm square or less. The pressure-sensitive adhesive sheet disclosed herein is capable of simultaneously energizing all of the conductive small pieces on the adhesive by arranging and fixing such a plurality of conductive small pieces on the pressure-sensitive adhesive layer. With this, it is possible to collectively inspect the conductive small pieces. Therefore, it can be said that the pressure-sensitive adhesive sheet disclosed herein is a pressure-sensitive adhesive sheet for inspecting electrical conductivity of a conductive piece. The above energization method is a method that fundamentally solves the technical and time limitations of individual 100% inspection using probe pins, which has been necessary in the past, and is a means for realizing product miniaturization and high performance with improved productivity. Can be. The pressure-sensitive adhesive sheet disclosed herein can be preferably used for such applications, and therefore has a great practical advantage.

<Method of manufacturing inspected conductive pieces>
Based on the above description, according to the present specification, a method for manufacturing an inspected conductive piece (for example, a semiconductor chip) is provided. This method can also be an inspection method for conductive particles. The method includes a step (preparing step) of preparing an adhesive sheet to which a plurality of conductive pieces to be inspected are fixed. In this preparation step, the plurality of conductive small pieces to be inspected are separably fixed to the surface of the pressure-sensitive adhesive layer. As the pressure-sensitive adhesive sheet, one having a pressure-sensitive adhesive layer having conductivity is used. The above method also includes a step (inspecting step) of energizing at least a part (for example, all) of the plurality of conductive pieces to be inspected through the adhesive layer and inspecting the conductive piece to be inspected in the energized state. Including. According to this method, it is possible to carry out a batch simultaneous energization inspection of a plurality of conductive pieces. In addition, this method may typically further include a step of contacting a surface of the plurality of conductive pieces to be inspected, which is opposite to the fixing surface with the adhesive layer, with a conductive material before the inspection step. .. Thereby, in the inspection step, the conductive small pieces to be inspected can be collectively energized via the adhesive layer and the conductive material. The details will be described below.

First, in this method, an adhesive sheet having a plurality of conductive small pieces to be inspected fixed is prepared (preparation process). For example, one conductive wafer is fixed to an adhesive sheet, and then the conductive wafer is processed on the adhesive sheet to form the plurality of conductive pieces from the conductive wafer. This makes it possible to prepare an adhesive sheet to which a plurality of conductive small pieces to be inspected are fixed. The pressure-sensitive adhesive sheet disclosed herein is preferably used as the pressure-sensitive adhesive sheet, but the pressure-sensitive adhesive sheet is not limited thereto, and a pressure-sensitive adhesive sheet having a known or common conductive pressure-sensitive adhesive layer may be used. The process of processing the conductive wafer (for example, a semiconductor wafer) may include a process of dicing the conductive wafer and an expansion process. The dicing step may be a step of breaking the wafer into small pieces by breaking after laser dicing with a laser beam or the like. Then, by the expansion (expansion step) of the adhesive sheet holding the small pieces, the small pieces on the adhesive layer are arranged at a predetermined interval.

In some other embodiments, a plurality of conductive pieces formed by using a known or conventional dicing pressure-sensitive adhesive sheet or expansion pressure-sensitive adhesive sheet, on the pressure-sensitive adhesive layer of the pressure-sensitive adhesive sheet having a conductive pressure-sensitive adhesive layer. An adhesive sheet to which a plurality of conductive small pieces to be inspected are fixed by transfer is prepared. As the conductive pressure-sensitive adhesive sheet, the pressure-sensitive adhesive sheet disclosed herein is preferably used.

Then, the exposed surface (the surface opposite to the surface fixed to the adhesive layer) of the plurality of conductive small pieces to be inspected fixed to the surface of the adhesive layer of the prepared adhesive sheet is brought into contact with the conductive material. Specifically, at least a part (preferably all) of the plurality of conductive pieces to be inspected is brought into contact with the conductive material. As the conductive material, the pressure-sensitive adhesive sheet (conductive pressure-sensitive adhesive sheet) disclosed herein is preferably used. Alternatively, a publicly known or commonly used conductive adhesive sheet may be used. As the conductive material, it is also possible to use a metal plate which has been conventionally used in a current inspection of a semiconductor chip or the like. The conductive material is usually placed on the opposite side of the inspection surface, so transparency is not required.

Next, a conductive material such as a probe pin or the like is connected to the pressure-sensitive adhesive layer of the pressure-sensitive adhesive sheet so as to be in a conductive state, and a different conductive inspection terminal (such as a probe pin) is connected to a conductive material. Is made conductive, and a current is passed through the pressure-sensitive adhesive layer and the conductive material. Thereby, at least a part (preferably all) of the plurality of conductive pieces to be inspected can be energized simultaneously and collectively. In this way, the energization inspection can be performed.

[FIG. 3] FIG. 3 is a schematic cross-sectional view for explaining an electric current inspection related to this method. In FIG. 3,

reference numerals

101, 110, and 120 respectively represent the pressure-sensitive adhesive sheet, the base material layer, and the pressure-sensitive adhesive layer (conductive pressure-sensitive adhesive layer) disclosed herein, and the reference numeral 201 represents a conductive material. In this embodiment, the pressure-sensitive adhesive sheet disclosed herein is used as the conductive material 201. The conductive material (pressure-sensitive adhesive sheet) 201 includes a base material layer 210 and a pressure-sensitive adhesive layer (conductive pressure-sensitive adhesive layer) 220. Prepare In the plurality of conductive pieces 150 fixed to the surface of the pressure-sensitive adhesive layer 120 of the pressure-sensitive adhesive sheet 101, the surface opposite to the surface fixed to the pressure-sensitive adhesive layer 120 has the surface of the pressure-sensitive adhesive layer 220 of the conductive material (pressure-sensitive adhesive sheet) 201. Is in contact with (specifically, adhesively fixed). Specifically, as shown in the figure, the plurality of conductive pieces 150 are arranged on the surface of the pressure-sensitive adhesive layer 120 so as to be separated from each other. The surface of the plurality of conductive pieces 150 opposite to the fixed surface with the adhesive layer 120 is covered with the conductive material (adhesive sheet) 201, whereby each conductive piece 150 has both surfaces. , The surface of the pressure-sensitive adhesive layer 120 of the pressure-sensitive adhesive sheet 101 and the surface of the pressure-sensitive adhesive layer 220 of the conductive material (pressure-sensitive adhesive sheet) 201 are brought into contact with each other (specifically, adhered), and electricity is supplied through the pressure-sensitive adhesive sheet 101 and the conductive material 201. It is possible. In FIG. 3, P is a current inspection terminal (probe pin), and C is an inspection camera. In addition, the conductive small pieces 150 in the figure are given reference numerals only to a few representative ones. In addition, the conductive piece 150 in this embodiment is a light emitting semiconductor chip, and has electrodes on both surfaces thereof in contact with the

adhesive layers

120 and 220.

The inspection uses the inspection camera C in this embodiment, but the inspection is not limited to this, and various optical inspection means and visual inspection may be used. The inspection means such as the inspection camera C inspects the plurality of conductive small pieces 150 simultaneously energized at the same time through the adhesive sheet 101 (specifically, the emission intensity and the light wavelength of the light emitting semiconductor chip are inspected. By performing the step (1), it is possible to collectively determine defective products and perform grading for the plurality of conductive small pieces 150. After the inspection is completed, each conductive piece is separated and removed from the adhesive sheet 101 and the conductive material 201, and then shipped as a product. Other specific items regarding the above method are as described in the present specification, and therefore, a duplicate description will be omitted.

The matters disclosed by this specification include the following.
(1) An adhesive sheet having an adhesive layer, comprising:
The surface resistance value of the adhesive layer is 1.0×10 ⁸ Ω/□ or less,
An adhesive sheet having an adhesive force to a stainless steel plate within a range of 0.01 to 4.0 N/20 mm.
(2) A pressure-sensitive adhesive sheet having a pressure-sensitive adhesive layer,
The pressure-sensitive adhesive layer contains a polymer having an oxyalkylene structural unit,
The oxyalkylene structural unit includes a polyoxyalkylene unit in which the number of moles of oxyalkylene is greater than 2.
The said polymer contains an oxyalkylene structural unit at a ratio of 35 weight% or more, The adhesive sheet.
(3) The pressure-sensitive adhesive sheet according to (1) or (2) above, which has a haze value of 50% or less.
(4) The pressure-sensitive adhesive sheet according to any of (1) to (3) above, wherein the pressure-sensitive adhesive layer contains an oxyalkylene structural unit.
(5) The pressure-sensitive adhesive sheet according to (4), wherein the pressure-sensitive adhesive layer contains a polymer having the oxyalkylene structural unit.
(6) The pressure-sensitive adhesive sheet according to (5), wherein the polymer having the oxyalkylene structural unit has the oxyalkylene structural unit in the side chain.
(7) The pressure-sensitive adhesive sheet according to any of (4) to (6) above, wherein the content of the oxyalkylene structural unit in the pressure-sensitive adhesive layer is 20 to 95% by weight.
(8) The pressure-sensitive adhesive sheet according to any of (1) to (7) above, wherein the pressure-sensitive adhesive layer contains an ionic compound.
(9) The pressure-sensitive adhesive sheet according to any one of (1) to (8), further including a base material layer, wherein the pressure-sensitive adhesive layer is provided on at least one surface of the base material layer.
(10) The pressure-sensitive adhesive sheet according to (9), wherein the base material layer is composed of a resin film having an elastic modulus of 50 MPa or more.
(11) The pressure-sensitive adhesive sheet according to (9) or (10), wherein an undercoat layer is arranged between the base material layer and the pressure-sensitive adhesive layer.

(12) A step of preparing a pressure-sensitive adhesive sheet to which a plurality of conductive small pieces (for example, semiconductor chips) to be inspected are fixed, wherein the pressure-sensitive adhesive sheet has a pressure-sensitive adhesive layer having conductivity, The conductive piece to be inspected is detachably fixed to the surface of the adhesive layer;
A step of energizing at least a part of the plurality of conductive pieces to be inspected through the adhesive layer, and inspecting the conductive piece to be inspected in the energized state;
A method of manufacturing an inspected conductive strip, comprising:
(13) The method according to (12), further comprising a step of bringing a surface of the plurality of conductive pieces to be inspected, which is opposite to a surface fixed to the adhesive layer, into contact with a conductive material before the inspection step. the method of.
(14) Before the step of preparing the pressure-sensitive adhesive sheet to which the conductive small pieces are fixed, a step of fixing a conductive wafer to the pressure-sensitive adhesive sheet, processing the conductive wafer, and removing the plurality of conductive wafers from the conductive wafer. The method according to (12) or (13) above, further comprising:
(15) The method according to (14), wherein the step of processing the conductive wafer includes a step of dicing the conductive wafer and may further optionally include an expansion step.
(16) The method according to (12) or (13), including a step of fixing the plurality of conductive pieces to the pressure-sensitive adhesive sheet before the step of preparing the pressure-sensitive adhesive sheet to which the conductive pieces are fixed. the method of.
(17) The method according to any of (12) to (16) above, wherein the adhesive sheet is the adhesive sheet according to any of (1) to (11) above.
(18) The method according to (13) above, wherein the conductive material is the adhesive sheet according to any one of (1) to (11) above.
(19) The method according to (13) above, wherein the conductive material is a metal plate or a conductive adhesive sheet.
(20) The above-mentioned steps (12) to (19), wherein the step of inspecting the conductive piece to be inspected includes an inspection through an adhesive sheet by an inspection means such as a camera or visual inspection (for example, inspection of a light emitting state of a light emitting semiconductor element). The method described in one of.

(21) A polymer containing an oxyalkylene structural unit,
The oxyalkylene structural unit includes a polyoxyalkylene unit in which the number of moles of oxyalkylene is greater than 2.
The pressure-sensitive adhesive composition, wherein the polymer contains oxyalkylene structural units in a proportion of 35% by weight or more.
(22) The pressure-sensitive adhesive composition according to (21), wherein the polymer having the oxyalkylene structural unit has the oxyalkylene structural unit in the side chain.
(23) The pressure-sensitive adhesive composition according to the above (21) or (22), wherein the proportion of the oxyalkylene structural unit is 20 to 95% by weight based on the solid content.
(24) The pressure-sensitive adhesive composition according to any of (21) to (23), which contains an ionic compound.
(25) The pressure-sensitive adhesive composition according to any of (21) to (24), wherein the polymer having an oxyalkylene structural unit is an acrylic polymer.

Hereinafter, some examples related to the present invention will be described, but the present invention is not intended to be limited to those shown in the specific examples. In addition, "part" and "%" in the following description are based on weight unless otherwise specified.

<Evaluation method>
[Adhesive force]
A pressure-sensitive adhesive sheet was cut into a size of 20 mm width×120 mm length to prepare a measurement sample, and the measurement sample was applied to a stainless steel plate (SUS430BA plate) ultrasonically cleaned in toluene at a linear pressure of 78.5 N/cm. Lamination is performed under the condition of a speed of 0.3 m/min. The bonding is performed in an atmosphere at a temperature of 23° C. and 50% RH. After standing in the same environment for 30 minutes, a tensile tester was used to peel the measurement sample from the stainless steel plate under the conditions of a tensile angle of 180 degrees and a speed of 0.3 m/min, and the peel strength at that time [N/20 mm ] Is measured as adhesive force. As the tensile tester, a product name “AUTOGRAPH AG-IS” manufactured by Shimadzu Corporation or its equivalent can be used. When the measurement sample is a double-sided pressure-sensitive adhesive sheet (for example, a substrate-less pressure-sensitive adhesive sheet), the non-measurement surface is lined with a PET film having a thickness of about 50 μm for measurement.

[Surface resistance value]
In a 23° C., 50% RH atmosphere, using a resistivity meter (Mitsubishi Chemical Analytical Co., Ltd., trade name “Loresta GX MCP-T700”), in accordance with JIS K 7194:1994, the four-probe method. The resistance value [Ω/□] on the surface of the pressure-sensitive adhesive layer is measured under the conditions of a predetermined applied voltage (automatically adjusted for each sample) and an application time of 30 seconds. As the measurement sample, for example, an adhesive sheet cut into a size of 50 mm width×50 mm length is used.

[Haze value]
(1) Haze Value of Adhesive Sheet An adhesive sheet is cut into a size of 50 mm width×50 mm length to prepare a measurement sample. The haze value (H1) of the measurement sample is measured according to JIS K 7136:2000 using "Haze Meter HM150" manufactured by Murakami Color Research Laboratory. This is defined as the haze value [%] of the adhesive sheet.
(2) Haze value of pressure-sensitive adhesive layer Further, only the base film used for the measurement sample was cut into a size of 50 mm x 50 mm, and the haze value (H2) was measured by the same method as in the above (1). From this, the haze value (H3) of the pressure-sensitive adhesive layer alone is calculated. This is defined as the haze value [%] of the adhesive layer.
Formula: H3=H1-H2
In the case of a substrate-less pressure-sensitive adhesive sheet consisting of only a pressure-sensitive adhesive layer, the haze value (H1) is measured from the one bonded to a PET film having a thickness of about 50 μm, and the PET film is the same as in the case of the above-mentioned substrate film. The haze value (H2) of the simple substance is measured, and the haze value (H3) of the adhesive layer alone is calculated from the above formula.
In addition, when the calculated value is less than 0.1 [%], it is described as 0 [%].

[Preparation of adhesive composition]
(Preparation example A1)
In a four-necked flask equipped with a stirring blade, a thermometer, a nitrogen gas introduction tube, and a condenser, methoxypolyoxyethylene (average number of moles of ethylene oxide added: 9) methacrylate/polyoxyethylene (average number of moles of ethylene oxide added: 9) methacrylate /Hydroxyethyl methacrylate was mixed at a molar ratio of 80/5/15. To 100 mol% of this monomer mixture, 0.15 mol% of 2,2'-azobisisobutyronitrile (AIBN) as a polymerization initiator and ethyl acetate were added, and nitrogen gas was introduced with gentle stirring to a predetermined amount. Polymerization reaction was carried out under the conditions described above to obtain a polymer A1 having Mw of 38×10 ⁴ and Mn of 6.5×10 ⁴ .

(Preparation Example A2)
As a monomer, the molar ratio of methoxy polyoxyethylene (average number of moles of ethylene oxide added 9) methacrylate/polyoxyethylene (average number of moles of ethylene oxide added 9) methacrylate/hydroxyethyl methacrylate/methyl methacrylate is 65/5/10/20. A monomer mixture was used. Otherwise in the same manner as in Preparation Example A1, a polymer A2 was obtained.

(Preparation Example A3)
As the monomer, the molar ratio of methoxypolyoxyethylene (average number of moles of ethylene oxide added 9) methacrylate/polyoxyethylene (average number of moles of ethylene oxide added 9) methacrylate/hydroxyethyl methacrylate/methyl methacrylate is 45/5/10/40. A monomer mixture was used. Otherwise in the same manner as in Preparation Example A1, a polymer A3 was obtained.

(Preparation example A4)
As the monomer, a monomer mixture in which the molar ratio of polyoxyethylene (average number of moles of ethylene oxide added: 9) methacrylate/hydroxyethyl methacrylate was 80/20 was used. Otherwise in the same manner as in Preparation Example A1, a polymer A4 was obtained.

(Preparation Example A5)
As the monomer, a monomer mixture in which the polyoxyethylene (average number of moles of ethylene oxide added: 9) methacrylate/hydroxyethyl methacrylate/methyl methacrylate was 60/20/20 was used. Otherwise in the same manner as in Preparation Example A1, a polymer A5 was obtained.

[Production of base material]
(Production Example B1)
An aqueous solution (Bytron P, HC) containing 0.5% of poly(3,4-ethylenedioxythiophene) (PEDOT) as a conductive polymer and 0.8% of polystyrene sulfonate (number average molecular weight 150,000) (PSS). (Manufactured by Stark) was prepared. In addition, a dispersion containing 25% of a polyester resin as a binder (manufactured by Toyobo Co., Ltd., trade name “Binaroll MD-1480” (aqueous dispersion of saturated copolymer polyester resin) was prepared. In a mixed solvent of water and ethanol, 100 parts by solid content of the binder dispersion, 50 parts by solid content of the conductive polymer aqueous solution, and 5 parts of melamine-based cross-linking agent were added and thoroughly mixed by stirring for about 20 minutes. A conductive undercoat layer-forming composition having an NV of about 0.4% was prepared, and the conductive undercoat layer-forming composition was applied to one surface of a PET film (elastic modulus 4.2 GPa) having a thickness of 50 μm, A conductive undercoat layer having a thickness of 300 nm was formed by drying for 60 seconds at 120° C. Thus, a substrate film B1 with a conductive undercoat layer was obtained.

(Production Example B2)
Instead of the PET film, a polyvinyl chloride film having a thickness of 70 μm (using dioctyl terephthalate as a plasticizer, elastic modulus 250 MPa) was used as the substrate. Otherwise in the same manner as in Production Example B1, a substrate film B2 with a conductive undercoat layer was obtained.

(Production Example B3)
Instead of the PET film, a 100 μm-thick multilayer extruded film of polypropylene/polyethylene/vinyl acetate copolymer (elastic modulus 600 MPa) was used as the substrate. Others were the same as that of manufacture example B1, and obtained the base material film B3 with a conductive undercoat layer.

(Production Example B4)
As the base material, a polypropylene/polyethylene blend film having a thickness of 40 μm (elastic modulus 600 MPa) was used instead of the PET film. Others were the same as that of manufacture example B1, and obtained base film B4 with a conductive undercoat layer.

<Example 1>
85 parts of polymer A1, 2.5 parts of isocyanate-based cross-linking agent (“Coronate HX” manufactured by Tosoh Corporation), lithium bis(trifluoromethanesulfonyl)imide (trade name “F-top EF-N115 manufactured by Mitsubishi Materials Electronic Chemicals”) )) and 0.016 part of ferric acetylacetone ferric acid (“Narsem ferric iron” manufactured by Nippon Kagaku Sangyo Co., Ltd.) in ethyl acetate were prepared as a pressure-sensitive adhesive composition according to this example. This pressure-sensitive adhesive composition was applied to the surface of the conductive undercoat layer of the substrate film B1 with a conductive undercoat layer, and dried at 130° C. for 90 seconds to form a pressure-sensitive adhesive layer having a thickness of 10 μm. In this way, a single-sided adhesive pressure-sensitive adhesive sheet according to this example was obtained.

<Examples 2-5>
The pressure-sensitive adhesive composition according to each example in the same manner as in Example 1 except that Polymer A2 (Example 2), Polymer A3 (Example 3), Polymer A4 (Example 4) or Polymer A5 (Example 5) was used instead of Polymer A1. A single-sided adhesive PSA sheet according to each example was obtained in the same manner as in Example 1 except that the prepared PSA composition was used.

<Example 6>
The pressure-sensitive adhesive composition according to Example 2 was prepared, and the above-mentioned pressure-sensitive adhesive composition was added to the conductive film of the base film B2 with a conductive undercoat layer in the same manner as in Example 2 except that the base film B2 with a conductive undercoat layer was used. The undercoat layer surface was coated and dried to obtain a one-sided adhesive pressure-sensitive adhesive sheet according to this example.

<Examples 7 to 8>
The pressure-sensitive adhesive composition according to Example 1 was prepared and the above-mentioned pressure-sensitive adhesive composition was electrically conductive in the same manner as in Example 1 except that the substrate film B3 (Example 7) or B4 (Example 8) with a conductive undercoat layer was used. Of the base film with a conductive undercoat layer was applied on the surface of the conductive undercoat layer and dried to obtain a single-sided adhesive pressure-sensitive adhesive sheet according to each example.

<Example 9>
85 parts of polyether polyol A ("PREMINOL S 3011" manufactured by AGC, molecular weight 10000), polyether polyol B ("SANNIX GP-3000" manufactured by Sanyo Kasei Kogyo, polyoxypropylene glyceryl ether, number average molecular weight 3000) ) 13 parts, polyether polyol C (“SANNIX GP-1000” manufactured by Sanyo Chemical Industry Co., Ltd., polyoxypropylene glyceryl ether, number average molecular weight 1000) 2 parts, polyfunctional isocyanate (“Coronate HX” manufactured by Tosoh Corporation) 18 parts, lithium bis(trifluoromethanesulfonyl)imide (Mitsubishi Materials Denshi Kasei's trade name "F-top EF-N115") 15 parts and acetylacetone ferric iron (Nippon Kagaku Sangyo Co., Ltd. "Narsem ferric iron") 0 An ethyl acetate solution of a pressure-sensitive adhesive containing 12 parts was prepared as a pressure-sensitive adhesive composition according to this example, and the pressure-sensitive adhesive composition was applied to the surface of the conductive undercoat layer of the base film B1 with a conductive undercoat layer. A curing treatment was performed under the conditions of 130° C. for 90 seconds to form a pressure-sensitive adhesive layer having a thickness of 10 μm, thus obtaining a single-sided pressure-sensitive adhesive sheet according to this example.

<Example 10>
In a four-necked flask equipped with a stirring blade, a thermometer, a nitrogen gas introduction tube, and a condenser, 82 parts of 2-ethylhexyl acrylate, 12 parts of N-vinylpyrrolidone, 3 parts of 4-hydroxyethyl acrylate, 3 parts of acrylic acid, and light Initiator (“OMNIRAD 651” manufactured by IGM Resins Italia Srl) 0.05 part, anti-aging agent (“Songnox 1010”) 0.1 part, cross-linking agent (“NK Ester A- manufactured by Shin Nakamura Chemical Co., Ltd.” HD-N") 0.05 part, conductive filler (ECKA's "Sil-shield Ag/glass 5/25s") 50 parts, conductive filler (Potters'"TP25S12") 150 parts UV light A (UV) curable syrup was prepared as a pressure-sensitive adhesive composition according to this example. This pressure-sensitive adhesive composition was applied onto a release layer of a polyester film with a silicone release layer, and a polyester film with a silicone release layer was further adhered to it, and was irradiated with UV having an illuminance of 50 mW/cm ² for 5 minutes to be cured. Thus, a substrateless double-sided pressure-sensitive adhesive sheet having a pressure-sensitive adhesive layer having a thickness of 30 μm was obtained.

<Example 11>
A substrateless double-sided pressure-sensitive adhesive sheet according to this example was obtained in the same manner as in Example 10 except that the thickness of the pressure-sensitive adhesive layer was changed to 50 μm.

Table 1 shows the schematic configuration of the adhesive sheet according to each example, the adhesive strength [N/20 mm], the surface resistance value [Ω/□], and the haze value [%].

As shown in Table 1, in the pressure-sensitive adhesive sheets according to Examples 1 to 9, since the surface resistance value of the pressure-sensitive adhesive layer is 10 ⁸ Ω/□ or less, a plurality of pressure-sensitive adhesive sheets arranged on the pressure-sensitive adhesive are passed through the pressure-sensitive adhesive layer. The conductive pieces (for example, semiconductor chips) can be energized all at once. In addition, the pressure-sensitive adhesive sheets of these examples have adhesive strength to the SUS plate in the range of 0.01 to 4.0 N/20 mm, so that the conductive small pieces are fixed with good adhesion and after the energization process, The conductive piece can be well separated from the surface of the pressure-sensitive adhesive layer. On the other hand, the pressure-sensitive adhesive sheets according to Examples 10 to 11 had good conductivity, but the pressure-sensitive adhesive strength exceeded 4.0 N/20 mm, and compared to Examples 1 to 9, the adherends were more easily separated and removed. Considered inferior. Further, the haze value also exceeds 50%, and it is considered that the inspection through the pressure-sensitive adhesive sheet is impossible or the inspection property is poor.
From the above results, the pressure-sensitive adhesive sheet in which the surface resistance value of the pressure-sensitive adhesive layer is 10 ⁸ Ω/□ or less and the adhesive force with respect to the SUS plate is in the range of 0.01 to 4.0 N/20 mm is obtained by It can be suitably used for simultaneous inspection of small pieces.

The specific examples of the present invention have been described above in detail, but these are merely examples and do not limit the scope of the claims. The technology described in the claims includes various modifications and changes of the specific examples illustrated above.

1, 2, 101, 201:

Adhesive sheet

10, 110, 210:

Base material layer

20, 120, 220: Adhesive layer 30: Undercoat layer 150: Conductive piece

Claims

An adhesive sheet comprising an adhesive layer,
The surface resistance value of the adhesive layer is 1.0×10 8 Ω/□ or less,
An adhesive sheet having an adhesive force to a stainless steel plate within a range of 0.01 to 4.0 N/20 mm.
The pressure-sensitive adhesive sheet according to claim 1, which has a haze value of 50% or less.
The pressure-sensitive adhesive sheet according to claim 1 or 2, wherein the pressure-sensitive adhesive layer contains an oxyalkylene structural unit.
The pressure-sensitive adhesive sheet according to claim 3, wherein the pressure-sensitive adhesive layer contains a polymer having the oxyalkylene structural unit.
The pressure-sensitive adhesive sheet according to claim 4, wherein the polymer having the oxyalkylene structural unit has the oxyalkylene structural unit in a side chain.
The pressure-sensitive adhesive sheet according to any one of claims 3 to 5, wherein the content ratio of the oxyalkylene structural unit in the pressure-sensitive adhesive layer is 20 to 95% by weight.
The pressure-sensitive adhesive sheet according to any one of claims 1 to 6, wherein the pressure-sensitive adhesive layer contains an ionic compound.
The pressure-sensitive adhesive sheet according to any one of claims 1 to 7, further comprising a base material layer, wherein the pressure-sensitive adhesive layer is provided on at least one surface of the base material layer.
The pressure-sensitive adhesive sheet according to claim 8, wherein the base material layer is made of a resin film having an elastic modulus of 50 MPa or more.
The pressure-sensitive adhesive sheet according to claim 8 or 9, wherein an undercoat layer is disposed between the base material layer and the pressure-sensitive adhesive layer.
An adhesive sheet comprising an adhesive layer,
The pressure-sensitive adhesive layer contains a polymer having an oxyalkylene structural unit,
The oxyalkylene structural unit includes a polyoxyalkylene unit in which the number of moles of oxyalkylene is greater than 2.
The said polymer contains an oxyalkylene structural unit at a ratio of 35 weight% or more, The adhesive sheet.
The pressure-sensitive adhesive sheet according to claim 11, which has a haze value of 50% or less.
The pressure-sensitive adhesive sheet according to claim 11 or 12, wherein the polymer having the oxyalkylene structural unit has the oxyalkylene structural unit in a side chain.
The pressure-sensitive adhesive sheet according to any one of claims 11 to 13, wherein the content ratio of the oxyalkylene structural unit in the pressure-sensitive adhesive layer is 20 to 95% by weight.
The pressure-sensitive adhesive sheet according to any one of claims 11 to 14, wherein the pressure-sensitive adhesive layer contains an ionic compound.
The pressure-sensitive adhesive sheet according to any one of claims 11 to 15, further comprising a base material layer, wherein the pressure-sensitive adhesive layer is provided on at least one surface of the base material layer.
The pressure-sensitive adhesive sheet according to claim 16, wherein the base material layer is made of a resin film having an elastic modulus of 50 MPa or more.
The pressure-sensitive adhesive sheet according to claim 16 or 17, wherein an undercoat layer is disposed between the base material layer and the pressure-sensitive adhesive layer.
A step of preparing a pressure-sensitive adhesive sheet having a plurality of conductive small pieces to be inspected fixed, wherein the pressure-sensitive adhesive sheet has an adhesive layer having conductivity, and the plurality of conductive small pieces to be inspected are Separably fixed to the surface of the agent layer;
A step of energizing at least a part of the plurality of conductive pieces to be inspected through the adhesive layer, and inspecting the conductive piece to be inspected in the energized state;
A method of manufacturing an inspected conductive strip, comprising:
20. The method according to claim 19, further comprising a step of bringing a surface of the plurality of conductive pieces to be inspected, which surface is opposite to a surface fixed to the adhesive layer, into contact with a conductive material before the inspection step.
Before the step of preparing the pressure-sensitive adhesive sheet to which the conductive small pieces are fixed, a step of fixing a conductive wafer to the pressure-sensitive adhesive sheet, processing the conductive wafer, and processing the plurality of conductive layers from the conductive wafer. 21. The method of claim 19 or 20, further comprising forming a small piece.
22. The method according to claim 21, wherein the step of processing the conductive wafer includes a step of dicing the conductive wafer, and may further optionally include an expansion step.
21. The method according to claim 19 or 20, comprising a step of fixing the plurality of conductive pieces to the pressure-sensitive adhesive sheet before the step of preparing the pressure-sensitive adhesive sheet to which the conductive pieces are fixed.
The method according to any one of claims 19 to 23, wherein the adhesive sheet is the adhesive sheet according to any one of claims 1 to 18.
The method according to claim 20, wherein the conductive material is the adhesive sheet according to any one of claims 1 to 18.
The method according to claim 20, wherein the conductive material is a metal plate or a conductive adhesive sheet.
The method according to any one of claims 19 to 26, wherein the step of inspecting the conductive small piece to be inspected includes an inspection through an adhesive sheet by an inspection means or visual inspection.
Including a polymer containing oxyalkylene structural units,
The oxyalkylene structural unit includes a polyoxyalkylene unit in which the number of moles of oxyalkylene is greater than 2.
The pressure-sensitive adhesive composition, wherein the polymer contains oxyalkylene structural units in a proportion of 35% by weight or more.
The pressure-sensitive adhesive composition according to claim 28, wherein the polymer having the oxyalkylene structural unit has the oxyalkylene structural unit in a side chain.
The pressure-sensitive adhesive composition according to claim 28 or 29, wherein the proportion of the oxyalkylene structural unit is 20 to 95% by weight based on the solid content.
The pressure-sensitive adhesive composition according to any one of claims 28 to 30, which contains an ionic compound.
The pressure-sensitive adhesive composition according to any one of claims 28 to 31, wherein the polymer having the oxyalkylene structural unit is an acrylic polymer.