KR102598588B1 - Adhesive sheets and their uses - Google Patents

Abstract

A novel adhesive sheet that can be suitably used for simultaneous inspection of a plurality of conductive small pieces is provided. An adhesive sheet including an adhesive layer is provided. The surface resistance value of the adhesive layer is 1.0×10 ⁸ Ω/□ or less. Additionally, this adhesive sheet has an adhesive force to a stainless steel plate within the range of 0.01 to 4.0 N/20 mm.

Description

Adhesive sheets and their uses

The present invention relates to adhesive sheets and their uses.

This application claims priority based on Japanese Patent Application No. 2019-020095 filed on February 6, 2019, the entire contents of which are incorporated herein by reference.

In general, adhesives (also called pressure-sensitive adhesives; the same applies hereinafter) are in a soft solid (viscoelastic) state in a temperature range around room temperature and have the property of easily adhering to an adherend by applying pressure. The adhesive is widely used in various fields in the form of a support-equipped adhesive sheet with an adhesive layer on the support or in the form of a support-free adhesive sheet without a support due to its good adhesion workability to the adherend, etc. there is. Such adhesives adhere to the adherend and, after completing their purpose of adhesion, can be removed from the adherend. Prior art documents disclosing this type of prior art include Patent Documents 1 and 2. Patent Documents 1 and 2 relate to a surface protection film that temporarily protects a polarizing plate bonded to a liquid crystal cell in the manufacture of a liquid crystal display panel, and disclose an adhesive having antistatic properties.

Japanese Patent No. 5061898 Specification Japanese Patent No. 5535987 Specification

However, the production volume of various semiconductor devices used in electronic products with display functions, etc. is increasing every year, and in response to requests for miniaturization and higher performance of products, the miniaturization of devices is also progressing. For this reason, we are faced with the problem of increasing the testability of the device and the time required for the test. Specifically, for example, for quality assurance of semiconductor chips such as light emitting diodes, an energization inspection is performed on all of the many chips formed during the manufacturing process. In this inspection, the probe pin is brought into direct contact with the electrode of each chip and electricity is applied to determine defective products, grade the chip, etc. However, with the above-described miniaturization of the chip, the electrode area also becomes smaller, making it difficult to accurately contact the probe pin with the microelectrode. In addition, as mentioned above, since inspection is performed on a chip basis, compared to the miniaturization of chips that can be performed on a wafer basis (typically miniaturization through a dicing process or an expand process), chip miniaturization is possible. The increase in inspection time is significant.

In response to the above technical limitations and decline in productivity, the present inventor has conceived a novel solution that is different from the conventional solution. The idea is to fix a plurality of conductive small pieces (for example, semiconductor chips) with a conductive adhesive, simultaneously bring the electrodes of the conductive small pieces into contact with the adhesive, and pass a current through the adhesive to each conductive small piece, thereby forming the adhesive. This means that all conductive pieces on the screen are inspected simultaneously and collectively. Based on this idea, as a result of studying the specification of a configuration suitable for simultaneous inspection of a plurality of conductive small pieces in batches, the present invention was completed. That is, the purpose of the present invention is to provide a novel adhesive sheet that can be suitably used for simultaneous inspection of a plurality of conductive small pieces. Another object of the present invention is to provide a method for manufacturing inspected conductive small pieces.

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

In the adhesive sheet of the above configuration, since the adhesive layer has conductivity above a predetermined level, a plurality of conductive small pieces (for example, semiconductor chips) are fixed on the adhesive layer, and a plurality of conductive small pieces are disposed on the adhesive through the adhesive layer. Simultaneous energization can be carried out simultaneously. In addition, by setting the adhesive force of the adhesive sheet to a specific range, the conductive small pieces can be fixed with high adhesive reliability, and the conductive small pieces can be well separated from the adhesive layer surface after completion of the energization process.

In some preferred embodiments, the haze value of the adhesive sheet is 50% or less. According to an adhesive sheet with a haze value limited to a predetermined value or less, inspection of the adherend fixed to the adhesive sheet can be performed through the adhesive sheet.

In some preferred embodiments, the adhesive layer includes oxyalkylene structural units. According to the adhesive layer containing an oxyalkylene structural unit, good conductivity is easy to be obtained, and it is also easy to realize both conductivity and transparency.

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 achieving both adhesion reliability and adherend separation and removability can be preferably obtained. In some embodiments, the polymer having the oxyalkylene structural unit has the oxyalkylene structural unit in its side chain. By providing an oxyalkylene structural unit in a side chain that has a higher degree of freedom of movement compared to the polymer main chain, higher conductivity can easily be obtained based on the degree of freedom.

In some preferred embodiments, the content ratio of the oxyalkylene structural unit in the adhesive layer is 20 to 95% by weight. By including a predetermined amount of oxyalkylene structural units in the adhesive layer, high conductivity is easy to be obtained, and it is easy to achieve both adhesion reliability and adherend separation and removability.

In some preferred embodiments, the adhesive layer includes an ionic compound. By containing an ionic compound, the adhesive layer can preferably exhibit high conductivity. Additionally, the use of an ionic compound is preferable in terms of maintaining transparency of the adhesive layer. Additionally, it is advantageous in that the adhesive layer can be made thinner compared to metal particles.

The pressure-sensitive adhesive sheet according to some preferred embodiments further includes a base layer. Additionally, the adhesive layer is provided on at least one side (for example, one side) of the base material layer. Since the adhesive sheet provided with the base material layer has a certain rigidity, it can be excellent in processability and handling. The base material layer according to a more preferred embodiment is comprised of a resin film having an elastic modulus of 50 MPa or more.

In some preferred embodiments, an undercoating layer is disposed between the base layer and the adhesive layer. By providing an undercoating layer, the anchoring properties of the adhesive layer are improved, and the adhesive remains on the adherend during peeling, preferably prevented.

Additionally, according to the present specification, a method for manufacturing an inspected conductive small piece (for example, a semiconductor chip) is provided. This method is a process of preparing an adhesive sheet on which a plurality of conductive small pieces to be inspected are fixed - where the adhesive sheet has a conductive adhesive layer, and the plurality of conductive small pieces to be inspected are separable on the surface of the adhesive layer. and a step of passing electricity to at least a portion of the plurality of conductive small pieces to be inspected through the adhesive layer and inspecting the conductive small pieces to be inspected in the energized state. According to the above method, simultaneous energization inspection of a plurality of conductive small pieces is possible. Typically, before the inspection process, this method may further include a step of bringing the surface of the plurality of conductive small pieces to be inspected, opposite to the fixing surface of the corresponding adhesive layer, into contact with a conductive material. In this method, in the inspection process, electricity is passed to the conductive piece to be inspected through the adhesive layer and the conductive material.

Additionally, the method of manufacturing the inspected conductive small piece may be a method of inspecting a conductive small piece (for example, a semiconductor chip).

Additionally, in some embodiments, the method includes a step of fixing a conductive wafer to the adhesive sheet before the step of preparing an adhesive sheet on which conductive small pieces (e.g., semiconductor chips) are fixed, and processing the conductive wafer, There may be a process of forming the plurality of conductive small pieces from the conductive wafer. The conductive wafer processing process may include a conductive wafer dicing process or an expansion process. In some other embodiments, before the step of preparing the adhesive sheet on which the conductive small pieces are fixed, a step of fixing a plurality of conductive small pieces formed by using another adhesive sheet or by another method to the adhesive sheet may be included. . As the adhesive sheet used in the above method, the adhesive sheet disclosed herein is suitable. Additionally, as the conductive material used in the above method, the adhesive sheet disclosed herein is preferable, or a metal plate or a known or common conductive adhesive sheet may be used. In some embodiments, the inspection process of the conductive small piece to be inspected includes inspection beyond the adhesive sheet by inspection means such as a camera or visual inspection (for example, inspection of the luminous intensity or light wavelength of a light-emitting semiconductor device). can do.

1 is a schematic cross-sectional view showing a configuration example of an adhesive sheet according to an embodiment.
Fig. 2 is a schematic cross-sectional view showing a structural example of an adhesive sheet according to another embodiment.
Fig. 3 is a schematic cross-sectional view illustrating an energization inspection of a conductive small piece according to an embodiment.

Hereinafter, preferred embodiments of the present invention will be described. In addition, matters other than those specifically mentioned in this specification and matters necessary for practicing the present invention can be understood by those skilled in the art based on the teachings regarding the implementation of the invention described in this specification and the technical common sense at the time of filing the application. The present invention can be implemented based on the content disclosed in this specification and common technical knowledge in the field. In addition, in the following drawings, members and parts that exert the same function may be described by assigning the same reference numeral, and overlapping descriptions may be omitted or simplified. In addition, the embodiments described in the drawings are modeled to clearly explain the present invention, and do not necessarily accurately represent the size or scale of the actually provided product.

In this specification, “adhesive” refers to a material that exhibits a soft solid (viscoelastic) state in a temperature range around room temperature and has the property of easily adhering to an adherend by pressure, as described above. The adhesive referred to herein, as defined in "CA Dahlquist, "Adhesion: Fundamental and Practice", McLaren & Sons, (1966) P. 143", generally has a complex tensile modulus E*(1Hz)<10 ⁷ dyne. It may be a material that has properties that satisfy /cm2 (typically, a material that has these properties at 25°C).

<Configuration example of adhesive sheet>

The pressure-sensitive adhesive sheet disclosed herein may be a pressure-sensitive adhesive sheet with a base material having the pressure-sensitive adhesive layer on one or both sides of a non-removable base material (support base material), or may be a pressure-sensitive adhesive sheet with an inorganic material such as a pressure-sensitive adhesive layer held by a release liner. A sheet (that is, an adhesive sheet without a non-peelable base material) may be used. The concept of adhesive sheet referred to herein may include what is referred to as adhesive tape, adhesive label, adhesive film, etc. In addition, the adhesive sheet disclosed herein may be in roll shape or in sheet form. Alternatively, it may be an adhesive sheet processed into more diverse shapes.

An example of the configuration of the adhesive sheet disclosed herein is shown in FIG. 1. This adhesive sheet (1) includes a base material layer (10) and an adhesive layer (20). The adhesive layer 20 is provided on one side (first side) 10A of the base material layer 10. As will be described in detail later, the adhesive layer 20 has conductivity. The surface (adhesive surface) 20A of the adhesive layer 20 has a structure in which at least the adhesive layer side is protected by a release liner (not shown) that serves as a release surface. Alternatively, the other surface 10B of the base material layer 10 is a peeling surface, and when the adhesive sheet 1 is wound, the adhesive layer 20 comes into contact with the other surface 10B, and the adhesive surface 20A is formed. It may be protected by the other side 10B of the layer.

Figure 2 shows another configuration example of a single-sided adhesive pressure-sensitive adhesive sheet. The adhesive sheet 2 shown in FIG. 2 includes a base material layer 10 and an adhesive layer 20, and further includes an undercoat layer 30 between the base layer 10 and the adhesive layer 20. . Specifically, one side 30B of the undercoat layer 30 is in contact with the base material layer 10, and the other side of the undercoat layer 30 (the side opposite to one side) 30A is in contact with the base layer 10. It is in close contact with the adhesive layer 20. By having such an undercoat layer 30, the anchoring properties of the adhesive layer 20 are improved and the occurrence of adhesive residue during separation and removal from the adherend is prevented. As will be described in detail later, the undercoat layer 30 may be conductive.

<Adhesive layer>

(Surface resistance value)

The adhesive layer of the adhesive sheet disclosed herein is characterized by its surface resistance value being 1.0×10 ⁸ Ω/□ or less (for example, less than 1.0×10 ⁸ Ω/□) in some typical embodiments. It is built. In this way, the adhesive layer whose surface resistance value is limited to a predetermined value or less has good conductivity and allows electricity to pass through the adhesive layer to the adherend. From the viewpoint of conductivity suitable for current conduction of the adherend, etc., the surface resistance value is preferably 1.0×10 ⁷ Ω/□ or less (for example, less than 1.0×10 ⁷ Ω/□), more preferably 1.0×10 ⁶ . Ω/□ or less ⁽ for ^example , ^less than 1.0 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 may be 1.0×10 ³ Ω/□ or more (for example, 1.0×10 ⁴ Ω/□ or more). The surface resistance value of the adhesive layer is measured by the method described in the Examples described later. In addition, the pressure-sensitive adhesive sheet disclosed in this specification includes an aspect in which the surface resistance value of the pressure-sensitive adhesive layer is not limited, and in such an aspect, the pressure-sensitive adhesive layer is not limited to having the surface resistance value.

(Haze value)

The haze value of the adhesive layer is not particularly limited, and may be, for example, about 80% or less. When inspecting the adherend through the adhesive sheet, the adhesive layer needs to have adequate transparency. From that viewpoint, it is appropriate that the haze value of the pressure-sensitive adhesive layer is approximately 50% or less (for example, approximately 30% or less), preferably approximately 10% or less, more preferably approximately 3% or less, even more preferably is approximately 1% or less (for example, less than 0.1%). The haze value is measured by the method described in the Examples described later.

(oxyalkylene structural unit)

In some preferred embodiments, the adhesive layer (which may also be an adhesive composition; the same applies hereinafter, unless otherwise specified) contains an oxyalkylene structural unit. According to the adhesive layer containing an oxyalkylene structural unit, good conductivity is easy to be obtained, and it is also easy to realize both conductivity and transparency. Embodiments of the pressure-sensitive adhesive layer containing an oxyalkylene structural unit include the use of any of polymers, oligomers, and other additives having an oxyalkylene structural unit, or a combination of a plurality of them, and among them, oxyalkylene structural unit. The use of polymers with structural units is preferred. By using such a polymer as the main component (base polymer) in the adhesive, oxyalkylene structural units can be incorporated at a predetermined content throughout the system.

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

The number of moles of the (poly)oxyalkylene unit in the oxyalkylene structural unit (also referred to as the number of added moles, typically the repeating number of oxyalkylene) is usually 1 or 2 or more. From the viewpoint of improving the mobility (electronic conductivity) of electrons (which may be in the form of ions) in the adhesive layer, the number of moles of the (poly)oxyalkylene unit is suitably greater than 2, preferably 3 or more, more preferably Preferably it is 5 or more, more 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 is suitably set to less than 30 from the viewpoint of synthesis (ease of polymerization) and handling of polymers having oxyalkylene structural units, etc. It is preferably less than 20, and may be, for example, 15 or less, 13 or less, or 11 or less (typically 10 or less). In an embodiment in which polymers, oligomers, etc. having oxyalkylene structural units are used, the number of moles of (poly)oxyalkylene units in the oxyalkylene structural units of such polymers, oligomers, etc. is also selected from the above-mentioned range. It can be.

The content ratio of the oxyalkylene structural unit in the adhesive layer (which may be the solid content of the adhesive composition) is set depending on the electrical conductivity to the adherend, etc., and is therefore not limited to a specific range. The content ratio of the oxyalkylene structural unit in the adhesive layer can be, for example, approximately 5% by weight or more. From the viewpoint of improving conductivity, it is appropriate to set it to approximately 10% by weight or more, and is preferably approximately 20% by weight. It is more than 50% by weight, more preferably about 30% by weight or more, still more preferably about 40% by weight or more, especially preferably about 50% by weight or more (for example, about 60% by weight or more). The upper limit of the content of oxyalkylene structural units in the adhesive layer is appropriately set to approximately 95% by weight or less, for example, taking into account adhesion reliability and adhesion and removability, etc., and may be approximately 85% by weight or less. It may be approximately 75% by weight or less, or approximately 65% by weight or less (for example, approximately 55% by weight or less).

(polymer)

In the technology disclosed herein, the type of adhesive constituting the adhesive layer is not particularly limited. The adhesive (which may also be an adhesive composition) is a variety of known acrylic polymers, rubber-based polymers, polyester-based polymers, urethane-based polymers, polyether-based polymers, silicone-based polymers, polyamide-based polymers, and fluorine-based polymers in the field of adhesives. It may contain one or two or more types of rubber-like polymers. From the viewpoint of adhesion performance, cost, etc., it is preferable to use acrylic polymer or urethane polymer. Among them, an adhesive containing acrylic polymer as a main component (acrylic adhesive) is more preferable.

“Acrylic polymer” refers to a polymer containing a monomer unit that constitutes the polymer and is derived from a monomer having at least one (meth)acryloyl group in one molecule. Hereinafter, a monomer having at least one (meth)acryloyl group in one molecule is also referred to as an “acrylic monomer.” Therefore, the acrylic polymer in this specification is defined as a polymer containing a monomer unit derived from an acrylic monomer. A typical example of an acrylic polymer is an acrylic polymer in which the proportion of acrylic monomers among all monomer components used in the synthesis of the acrylic polymer is more than 50% by weight.

In addition, “(meth)acryloyl” refers comprehensively to acryloyl and methacryloyl. Likewise, “(meth)acrylate” refers comprehensively to acrylate and methacrylate, and “(meth)acrylic” refers to acrylic and methacrylic, respectively.

“Urethane-based polymer” is a unit constituting the polymer and includes polyol and polyfunctional isocyanate, and refers to a polymer obtained by polymerization reaction (polyaddition) between the hydroxyl group of the polyol and the isocyanate group of the polyfunctional isocyanate through a urethane bond. The polyol and polyfunctional isocyanate before the reaction typically exist in the form of a monomer or oligomer (hereinafter sometimes collectively referred to as “monomer”), and the urethane-based polymer obtained by the above reaction is typically derived from polyol. It has a structure in which segments derived from polyfunctional isocyanates are alternately repeated. Additionally, the monomers include so-called macro monomers.

In addition, “oligomer” in this specification shall refer to a polymer having a molecular weight of less than 3.0×10 ⁴ . As the molecular weight of the oligomer, the weight average molecular weight (Mw) in terms of standard polystyrene determined by gel permeation chromatography (GPC) or the molecular weight calculated from the chemical formula is adopted.

(polymer with oxyalkylene structural units)

In some preferred embodiments, the pressure-sensitive adhesive layer (which may also be a pressure-sensitive adhesive composition) includes an oxyalkylene structural unit-containing polymer. Thereby, good conductivity is easy to obtain. 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 within the polymer structure (for example, within the network structure). Among them, use of a polymer having an oxyalkylene structural unit in the side chain is more preferable. By arranging an oxyalkylene structural unit in the side chain, high conductivity can easily be obtained based on its high degree of freedom. In the configuration where the polymer side chain has an oxyalkylene structural unit, the chemical structure of the side chain is not particularly limited as long as it has an oxyalkylene structural unit. The polymer side chains may be in the form of, for example, (poly)oxyalkylene monoalcohols, (poly)oxyalkylene monoalkyl ethers. 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, etc., or a functional group such as a hydroxyl group.

The content of the oxyalkylene structural unit in the oxyalkylene structural unit-containing polymer is set depending on the electrical conductivity to the adherend, etc., and is therefore not limited to a specific range. The proportion of oxyalkylene structural units in the polymer can be, for example, approximately 10% by weight or more, and from the viewpoint of improving conductivity, it is appropriate to set it to approximately 25% by weight or more, preferably approximately 35% by weight or more, More preferably, it is approximately 45% by weight or more, further preferably is approximately 55% by weight or more, and particularly preferably is approximately 65% by weight or more (for example, approximately 70% by weight or more). The upper limit of the proportion of oxyalkylene structural units in the polymer is not particularly limited, and taking into account adhesion reliability, adhesion and removal properties, etc., it is appropriate to set it to approximately 95% by weight or less, for example, approximately 90% by weight. It may be less than or equal to approximately 85% by weight, or approximately 75% by weight or less (for example, approximately 70% by weight or less).

A polymer containing an oxyalkylene structural unit can be obtained by polymerizing a monomer having an oxyalkylene structural unit. The polymerization method is not particularly limited and may include radical polymerization, ionic polymerization, polycondensation, and polyaddition. Alternatively, for example, a polymer having an oxyalkylene structural unit can be obtained by adding an oxyalkylene structural unit to the polymer. For example, there is 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. According to this method, a polymer having an oxyalkylene structural unit in the side chain can be preferably obtained.

In some embodiments, the monomer having an oxyalkylene structural unit is a compound having a polymerizable reactive group such as a vinyl group or a (meth)acryloyl group, and an oxyalkylene structural unit. For example, acrylic monomers having an oxyalkylene structural unit, vinyl ether monomers having an oxyalkylene structural unit, polycarboxylic acid monomers having an oxyalkylene structural unit (e.g., oxyalkylene structures such as PEG) A unit-containing compound added (for example, esterified) to maleic anhydride or the like is exemplified. From points such as polymerizability, it is preferable to use an acrylic monomer having an oxyalkylene structural unit.

(Acrylic polymer with oxyalkylene structural unit)

In some preferred embodiments, the oxyalkylene structural unit-containing polymer is an acrylic polymer having oxyalkylene structural units. Hereinafter, as a preferred example, the description will focus on an acrylic polymer containing an oxyalkylene structural unit, but it is not intended to limit the polymer containing an oxyalkylene structural unit disclosed herein to an acrylic polymer.

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

Examples of the (poly)oxyethylene unit-containing acrylic monomer include alkoxy(poly)ethylene glycol (meth)acrylate such as methoxypolyethylene glycol (meth)acrylate and ethoxypolyethylene glycol (meth)acrylate; (poly)ethylene glycol (meth)acrylate such as polyethylene glycol (meth)acrylate; etc. can be mentioned. Examples of the (poly)oxypropylene unit-containing acrylic monomer include alkoxy(poly)propylene glycol (meth)acrylate such as methoxypolypropylene glycol (meth)acrylate and ethoxypolypropylene glycol (meth)acrylate; (poly)propylene glycol (meth)acrylate such as polypropylene glycol (meth)acrylate; etc. can be mentioned. These can be used individually or in combination of two or more types. Among them, from the viewpoint of electronic conductivity, use of an acrylic monomer containing (poly)oxyethylene units is preferable. In the above monomer, the terminal on the oxyalkylene structural unit side may be an alkyl group such as a methyl group, a phenyl group, etc., or may be a functional group such as a hydroxyl group. The terminal structure of the monomer can be appropriately set considering crosslinking reaction, etc.

The amount of the oxyalkylene structural unit-containing monomer (preferably an oxyalkylene structural unit-containing acrylic monomer) used is set according to the electrical conductivity and adhesive properties to the adherend and is therefore not limited to a specific range. 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 monomers (hereinafter also referred to as “total monomer component”) used in the synthesis of the oxyalkylene structural unit-containing polymer. can do. From the viewpoint of improving conductivity, it is appropriate that the amount of the monomer containing an oxyalkylene structural unit in the total amount of monomers is approximately 30 mol% or more, preferably approximately 45 mol% or more, more preferably approximately 55 mol% or more, even more preferably is approximately 65 mol% or more, particularly preferably approximately 75 mol% or more (for example, approximately 80 mol% or more). In addition, from the viewpoint of cohesiveness, adhesiveness, etc., it is appropriate that the amount of the oxyalkylene structural unit-containing monomer used in the total amount of monomers is approximately 95 mol% or less, preferably approximately 90 mol% or less, and may be approximately 80 mol% or less, It may be approximately 70 mol% or less, and may be approximately 60 mol% or less (for example, approximately 50 mol% or less).

As the oxyalkylene structural unit-containing polymer in the technology disclosed herein, one obtained by copolymerizing a monomer having a hydroxyl group (-OH) can be preferably used. Specific examples of hydroxyl group-containing monomers include 2-hydroxyethyl (meth)acrylate, 2-hydroxypropyl (meth)acrylate, 3-hydroxypropyl (meth)acrylate, and 2-hydroxybutyl (meth)acrylate. and hydroxyl group-containing acrylic monomers such as 4-hydroxybutyl (meth)acrylate. These hydroxyl-containing monomers may be used individually or in combination of two or more types. A polymer copolymerized with such monomers is preferable because it is easy to obtain an adhesive that achieves both adhesive fixation and separation/removal of the adherend. For example, since it becomes easy to control the peeling force from the adherend to a low level, it is easy to obtain an adhesive excellent in separation and removability of the adherend. In addition, since it is easier to obtain effects such as improved cohesion when the hydroxyl group-containing side chain in the polymer is shorter, the distance from the polymerization reactor (typically a (meth)acryloyl group) of the hydroxyl group-containing monomer to the hydroxyl group is shorter. A hydroxyl group-containing monomer (in the case of hydroxy(meth)acrylate, a monomer with a small number of carbon atoms in the hydroxyalkyl group) is preferably used.

From the viewpoint of sufficiently demonstrating the effect of using the monomer, it is appropriate to use the hydroxyl group-containing monomer in a ratio of approximately 1 mol% or more, preferably approximately 3 mol%, of the total amount of monomers used in the synthesis of the oxyalkylene structural unit-containing polymer. or more, more preferably approximately 5 mol% or more, further preferably approximately 8 mol% or more, and may be approximately 12 mol% or more (approximately 15 mol% or more). In addition, the amount of the hydroxyl group-containing monomer in the total amount of monomers used in the synthesis of the polymer is suitably approximately 40 mol% or less, preferably approximately 30 mol% or less, more preferably approximately 20 mol%, considering the cohesiveness and adhesive strength of the adhesive. % or less.

In some preferred embodiments, the oxyalkylene structural unit-containing polymer includes, as a monomer unit, a monomer (high Tg monomer) whose homopolymer Tg (glass transition temperature) is approximately 10°C or higher. By copolymerizing a high Tg monomer, the cohesiveness of the adhesive can be improved and the adhesive strength can be improved. Additionally, separation and removal properties, such as preventing adhesive residue, tend to improve. From the viewpoint of improving cohesiveness, in some embodiments, the Tg of the homopolymer, which is a high Tg monomer, is suitably approximately 30°C or higher (e.g., approximately 50°C or higher), may be approximately 70°C or higher, or approximately 90°C. It can be more than that. Additionally, the upper limit of the Tg of the homopolymer, which is a high Tg monomer, is not particularly limited, and from the viewpoint of ease of polymer synthesis, etc., it is usually appropriate to be approximately 200°C or lower. In some embodiments, the Tg of the homopolymer, which is a high Tg monomer, may be approximately 180°C or lower, approximately 150°C or lower, or approximately 120°C or lower.

Among the monomers exemplified as monomers that can be used in the synthesis of oxyalkylene structural unit-containing polymers, high Tg monomers having a homopolymer Tg of a certain level or higher can be used without particular limitation. For example, one or two or more types of monomers selected from other monomers such as alkyl (meth)acrylates and various functional group-containing monomers as exemplified below can be used. Among them, alkyl (meth)acrylate is preferable, and among them, alkyl methacrylate (typically methyl methacrylate) whose alkyl group has a carbon atom number in the range of 1 to 4 can be preferably employed.

The high Tg monomer can be approximately 1 mol% or more of the total amount of monomers used in the synthesis of the oxyalkylene structural unit-containing polymer, and from the viewpoint of improving the cohesiveness and adhesive strength of the adhesive, it is appropriate to set it to approximately 5 mol% or more. , preferably approximately 10 mol% or more, more preferably approximately 15 mol% or more, and may be approximately 25 mol% or more (for example, approximately 35 mol% or more). In addition, the amount of high Tg monomer in the total amount of monomers used in the synthesis of the polymer is suitably approximately 60 mol% or less, preferably approximately 50 mol% or less, more preferably approximately 40 mol% or less (e.g. For example, approximately 30 mol% or less). In some other embodiments, the amount of the high Tg monomer in the total amount of monomers may be less than 10 mol% or less than 1 mol%. The oxyalkylene structural unit-containing polymer may be one that does not substantially contain high Tg monomers as monomer units.

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

The amount of alkyl (meth)acrylate (e.g., alkyl (meth)acrylate that does not correspond to the above high Tg monomer) used in the synthesis of the polymer containing oxyalkylene structural units is determined from the viewpoint of cohesiveness, adhesiveness, etc. It can be approximately 30 mol% or less in the total amount of monomers, for example, approximately 10 mol% or less, or approximately 1 mol% or less. The oxyalkylene structural unit-containing polymer may be one that does not substantially contain alkyl (meth)acrylate (for example, alkyl (meth)acrylate that does not correspond to the above-mentioned high Tg monomer) as a monomer unit.

The oxyalkylene structural unit-containing polymer disclosed herein may be copolymerized with monomers other than the oxyalkylene structural unit-containing monomer and the hydroxyl group-containing monomer (other monomers). These monomers can be used, for example, for purposes such as adjusting adhesion performance (e.g., separation and removability of adherends). For example, monomers that can improve the cohesion or heat resistance of the adhesive include monomers containing sulfonic acid groups, monomers containing phosphoric acid groups, monomers containing cyano groups, vinyl esters such as vinyl acetate, and aromatic vinyl compounds such as styrene. . In addition, as monomers (functional group-containing monomers) that can introduce functional groups that can serve as crosslinking origins into acrylic polymers or contribute to improving adhesive strength, monomers containing carboxyl groups such as acrylic acid and methacrylic acid; A monomer containing an acid anhydride group such as maleic anhydride; Amide group-containing monomers such as acrylamide; Amino group-containing monomer; Imide group-containing monomer; Monomer containing an epoxy group; Cyclic monomers having a nitrogen atom such as (meth)acryloylmorpholine and N-vinylpyrrolidone; Vinyl ethers, etc. can be mentioned. Additionally, as other monomers, polyfunctional monomers can be used as copolymerizable components for purposes such as crosslinking treatment. As the multifunctional monomer, one or two or more of hexanediol di(meth)acrylate, polyethylene glycol di(meth)acrylate, polypropylene glycol di(meth)acrylate, etc. can be used. The other monomers may be used individually or in combination of two or more.

The amount of the other monomer used may be approximately 30 mol% or less of the total amount of monomers used in the synthesis of the oxyalkylene structural unit-containing polymer from the viewpoint of sufficiently expressing the characteristics of the oxyalkylene structural unit-containing monomer, for example For example, it may be approximately 10 mol% or less, and may be approximately 1 mol% or less. The oxyalkylene structural unit-containing polymer may be a monomer unit that does not substantially contain the other monomers mentioned above.

The method for obtaining the oxyalkylene structural unit-containing polymer is not particularly limited, and includes methods for synthesizing polymers (e.g., acrylic polymers) such as solution polymerization, emulsion polymerization, bulk polymerization, suspension polymerization, and photopolymerization. Various known polymerization methods can be appropriately employed. For example, a solution polymerization method can be preferably employed. The polymerization temperature when performing solution polymerization can be appropriately selected depending on the type of monomer and solvent used, the type of polymerization initiator, etc., for example, about 20°C to 170°C (typically about 40°C to 140°C). can do. Additionally, the polymer may be a random copolymer, a block copolymer, or a graft copolymer. From the viewpoint of productivity etc., random copolymers are usually preferable.

The solvent (polymerization solvent) used in solution polymerization can be appropriately selected from conventionally known organic solvents. For example, aromatic compounds (typically aromatic hydrocarbons) such as toluene; Acetic acid esters such as ethyl acetate; Aliphatic or alicyclic hydrocarbons such as hexane and cyclohexane; Halogenated alkanes such as 1,2-dichloroethane; lower alcohols such as isopropyl alcohol (for example, monohydric alcohols having 1 to 4 carbon atoms); ethers such as tert-butylmethyl ether; Ketones such as methyl ethyl ketone; Any one type of solvent selected from the like, or a mixed solvent of two or more types can be used.

The initiator used for polymerization can be appropriately selected from conventionally known polymerization initiators depending on the type of polymerization method. For example, one or two or more types of azo-based polymerization initiators such as 2,2'-azobisisobutyronitrile (AIBN) can be preferably used. Other examples of polymerization initiators include persulfates such as potassium persulfate; Peroxide-based initiators such as benzoyl peroxide and hydrogen peroxide; substituted ethane-based initiators such as phenyl-substituted ethane; aromatic carbonyl compounds; etc. can be mentioned. Another example of a polymerization initiator is a redox initiator made by combining a peroxide and a reducing agent. Such polymerization initiators can be used individually or in combination of two or more types. The amount of the polymerization initiator used may be a normal amount, and can be selected from the range of approximately 0.005 to 1 part by weight (typically approximately 0.01 to 1 part by weight) per 100 parts by weight of the monomer component.

The oxyalkylene structural unit-containing polymer disclosed herein preferably has a weight average molecular weight (Mw) equivalent to standard polystyrene obtained by GPC (gel permeation chromatography) of approximately ³ From the viewpoint of performance, etc., it is preferably approximately 10×10 ⁴ or more, more preferably approximately 20×10 ⁴ or more, and even more preferably approximately 30×10 ⁴ or more. In addition, the upper limit of the Mw is not particularly limited, and for example, it is suitably approximately 500 × 10 ⁴ or less, and from the viewpoint of adhesive strength, coatability when forming an adhesive layer, etc., preferably approximately 100 × 10 ⁴ or less, More preferably, it is approximately 70×10 ⁴ or less, and may be approximately 50×10 ⁴ or less.

The dispersion degree (Mw/Mn) of the oxyalkylene structural unit-containing polymer disclosed herein is not particularly limited. The dispersion degree (Mw/Mn) herein refers to the dispersion degree (Mw/Mn) expressed as the ratio of the weight average molecular weight (Mw) to the number average molecular weight (Mn). In a preferred embodiment, the dispersion degree (Mw/Mn) of the oxyalkylene structural unit-containing polymer is suitably approximately 15 or less, and from the viewpoint of suitably exhibiting cohesiveness based on a relatively uniform high molecular weight, preferably It is approximately 10 or less, more preferably approximately 7 or less. In addition, the Mw/Mn is theoretically 1 or more, for example, may be 2 or more, 3 or more, or 4 or more (typically 5 or more).

Specifically, the Mw and Mn can be measured under the following conditions using the product name "HLC-8120GPC" (manufactured by Tosoh Corporation) as a GPC measuring device.

[GPC measurement conditions]

Sample concentration: 0.2% by weight (tetrahydrofuran solution)

Sample injection volume: 100 μL

Eluent: Tetrahydrofuran (THF)

Flow rate (flow rate): 0.8mL/min

Column temperature (measurement temperature): 40℃

Column: Tosoh Corporation, G7000H _XL +GMH _XL +GMH _XL

Column size: 7.8㎜ϕ×30㎝ each, 90㎝ in total

Detector: Differential refractometer (RI)

Standard sample: polystyrene

(Urethane-based polymer having oxyalkylene structural units)

In some embodiments, the pressure-sensitive adhesive layer may contain 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, compositions in which polyol is mixed in excess of polyfunctional isocyanate), oxyalkylene structural units are added. It may also have a side chain. The oxyalkylene structural unit may be derived from either a polyol or a polyfunctional isocyanate constituting the urethane-based polymer. However, from the ease of introduction into the polymer structure, the use of a polyol having an oxyalkylene structural unit is preferred for the urethane-based polymer. Oxyalkylene structural units may be introduced.

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

The average number of functional groups of the polyol used to form the urethane polymer is approximately 2 or more, and from the viewpoint of improving cohesion, etc., it is appropriate to set it to approximately 2.5 or more (for example, approximately 2.8 or more). The average number of functional groups is usually approximately 5 or less, and from the viewpoint of adhesion etc., it is appropriate to set it to approximately 4 or less (for example, approximately 3.5 or less).

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

In some preferred embodiments, the polyol used to form the urethane-based polymer contains one or two or more types of a polyol as the main component (main polyol) and a secondary polyol (minor polyol) with a lower molecular weight than the main component. It may be. By using the main polyol and the burriol in combination, the effect achieved by the technology disclosed herein can be preferably exhibited or controlled. The types of the main polyol and secondary polyol are not particularly limited, and may be any of, for example, polyester polyol, polyether polyol, polycaprolactone polyol, polycarbonate polyol, and castor oil-based polyol. Among them, polyester polyol and polyether polyol are preferable, and polyether polyol is more preferable. Specific examples of polyether polyol include the polyether polyols exemplified above.

The molecular weight of the main polyol used is appropriately set depending on conductivity, adhesive properties, etc., so it is not limited to a specific range, and is usually approximately 3000 or more, and is appropriate to be approximately 5000 or more (for example, approximately 8000 or more). The upper limit of the molecular weight of the main polyol is, for example, less than 3.0 × 10 ⁴ , and is preferably approximately 2.0 × 10 ⁴ or less, and may be approximately 1.5 × 10 ⁴ or less (for example, 1.2 × 10 ⁴ or less). As the subpolyol, one or two or more types of polyols whose molecular weight is smaller than that of the main polyol can be used. The molecular weight of one or two or more types of subpolyols may be approximately 300 or greater, preferably approximately 500 or greater, further approximately 800 or greater, or approximately 1000 or greater, for example, approximately 1,500 or greater, and may be, for example, approximately 1.0 or greater. It may be less than ×10 ⁴ , preferably approximately 7000 or less, further approximately 5000 or less, or approximately 2500 or less, for example, approximately 1200 or less.

The average number of functional groups of the main polyol is approximately 2 or more, and from the viewpoint of improving cohesion, etc., it is appropriate to set it to approximately 2.5 or more (for example, approximately 2.8 or more). The average number of functional groups is usually approximately 5 or less, and from the viewpoint of adhesion etc., it is appropriate to set it to approximately 4 or less (for example, approximately 3.5 or less). The average number of functional groups of each subpolyol is approximately 2 or more, and from the viewpoint of improving cohesion, etc., it is appropriate to set it to approximately 2.5 or more (for example, approximately 2.8 or more). The average number of functional groups is usually approximately 5 or less, and from the viewpoint of adhesion etc., it is appropriate to set it to approximately 4 or less (for example, approximately 3.5 or less).

As the polyol used to form the urethane-based polymer, in an embodiment in which a main polyol and a minor polyol are used together, the weight ratio of the main polyol and the minor polyol (main polyol/secondary polyol) is not particularly limited, for example, approximately 10/90. It can be more than 25/75, preferably about 25/75 or more, preferably about 50/50 or more, and may be about 70/30 or more (for example, about 80/20 or more). In addition, the weight ratio (main polyol/minor polyol) can be, for example, approximately 99/1 or less, and is preferably approximately 95/5 or less (for example, approximately 90/10 or less).

As the polyfunctional isocyanate used in forming the urethane-based polymer, one or two or more appropriate ones can be selected from compounds having a plurality of isocyanate groups. Examples of polyfunctional isocyanates include: aromatic isocyanates such as tolylene diisocyanate, diphenylmethane diisocyanate, and xylene diisocyanate; Alicyclic isocyanates such as cyclopentylene diisocyanate, cyclohexylene diisocyanate, and isophorone diisocyanate; Aliphatic isocyanates such as butylene diisocyanate and hexamethylene diisocyanate; etc. can be mentioned. More specifically, trimethylolpropane/tolylene diisocyanate trimer adduct (manufactured by Tosoh Corporation, brand name “Coronate L”), trimethylolpropane/hexamethylene diisocyanate trimer adduct (manufactured by Tosoh Corporation, brand name “Coronate HL”) ), isocyanate adducts such as the isocyanurate form of hexamethylene diisocyanate (manufactured by Tosoh Corporation, brand name “Coronate HX”); etc. are suitable. Such polyfunctional isocyanate may be used individually by 1 type, or may be used in combination of 2 or more types.

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

The content of polyfunctional isocyanate for forming the urethane-based polymer can be set according to the equivalence ratio with the polyol (NCO group / OH group), polyol molecular weight, polyfunctional isocyanate molecular weight, etc., and is not limited to a specific range. In the adhesive composition for forming an adhesive layer, the content of the polyfunctional isocyanate may be, for example, approximately 1 part by weight or more, and is preferably approximately 5 parts by weight or more, based on 100 parts by weight of the polyol. Preferably it is approximately 10 parts by weight or more, and may be approximately 15 parts by weight or more. In addition, the upper limit of the content of the polyfunctional isocyanate relative to 100 parts by weight of the polyol can be, for example, approximately 50 parts by weight or less, and is preferably approximately 30 parts by weight or less, preferably approximately 25 parts by weight. It may be less than or equal to about 20 parts by weight, for example.

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

The content ratio of the oxyalkylene structural unit-containing polymer in the adhesive layer disclosed herein is set depending on the electrical conductivity to the adherend, etc., and is therefore not limited to a specific range. The content ratio of the oxyalkylene structural unit polymer in the adhesive layer can be, for example, approximately 30% by weight or more, and from the viewpoint of improved conductivity, both adhesion reliability and adherend separation and removability, it is approximately 50% by weight or more. (typically more than 50% by weight) is appropriate, preferably approximately 60% by weight or more, more preferably approximately 70% by weight or more, further preferably approximately 80% by weight or more, and approximately 90% by weight or more. You can continue. The upper limit of the content of the oxyalkylene structural unit polymer in the adhesive layer is appropriately set to approximately 95% by weight or less, for example, approximately 90% by weight, taking into account adhesion reliability, adhesion and removal properties, conductivity, etc. It may be % or less.

(ionic compound)

The adhesive layer (which may also be an adhesive composition) disclosed herein preferably contains an ionic compound as a conductive component. By containing an ionic compound, the adhesive layer can preferably exhibit good conductivity. The use of an ionic compound is also preferable in terms of maintaining transparency of the adhesive layer. In an aspect of using a pressure-sensitive adhesive layer containing an oxyalkylene structural unit, the oxyalkylene structural unit in the pressure-sensitive adhesive layer can exhibit good conductivity by serving as a transport medium for the ionic compound or by electrically carrying the ionic compound. there is.

Examples of ionic compounds include alkali metal salts and ionic liquids. These may be used individually by 1 type, or may be used in combination of 2 or more types. In addition, here, “ion liquid” (sometimes referred to as room temperature molten salt) refers to a molten salt (ionic compound) that exhibits a liquid state at 40°C or lower. Since ionic liquids are in a liquid state at 40°C or lower, they can be added to, dispersed in, or dissolved in an adhesive more easily than solid salts in this temperature range. Additionally, since ionic liquids have no vapor pressure (non-volatility), they do not disappear over time and can continue to exhibit conductivity.

(Alkali metal salt)

In some preferred embodiments, alkali metal salts are used as the ionic compounds. Typical examples of alkali metal salts include lithium salts, sodium salts, and potassium salts. For example, Li ⁺ , Na ⁺ or K ⁺ as cationic components and Cl ^- , Br ^- , I ^- , BF ₄ ^- , PF ₆ ^- , SCN ^- , ClO ₄ ^- , CF ₃ SO ₃ ^- as anionic components. Metal salts containing (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. Because of its high dissociability, the use of lithium salts is preferred. Preferred examples include 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 Lithium salts such as SO ₂ ) ₃ C can be mentioned. In particular, lithium salts in which the anion component is a fluorine-containing anion such as a bis(perfluoroalkylsulfonyl)imide anion or a perfluoroalkylsulfonium anion (for example, Li(CF ₃ SO ₂ ) ₂ N, Li(C ₂ F ₅ SO ₂ ) ₂ N, LiCF ₃ SO ₃ ) is preferred. Such alkali metal salts may be used individually or in combination of two or more types.

(ionic liquid)

As the ionic liquid, any one or more of a nitrogen-containing onium salt, a sulfur-containing onium salt, and a phosphorus-containing onium salt 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 may be the same or different, and each represents a hydrogen atom, 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, R _c is absent.

In the 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 may be the same or different, and each represents a hydrogen atom, 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 may be the same or different, and each represents a hydrogen atom, a hydrocarbon group having 1 to 16 carbon atoms, or a functional group containing a hetero atom.

In the formula (D), Z represents a nitrogen atom, a sulfur atom, or a phosphorus atom. R _l , R _m , R _n and R _o may be the same or different, and 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, R _o is absent.

In the 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 formula (A) include pyridinium cation, pyrrolidinium cation, piperidinium cation, cation having a pyrroline skeleton, and cation having a pyrrole skeleton.

Specific examples of pyridinium cations 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, etc. are mentioned.

Specific examples of pyrrolidinium cations 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-butylpy Rolidinium, 1-ethyl-1-pentylpyrrolidinium, 1-ethyl-1-hexylpyrrolidinium, 1-ethyl-1-heptylpyrrolidinium, 1,1-dipropylpyrrolidinium, 1-propyl- Examples include 1-butylpyrrolidinium, 1,1-dibutylpyrrolidinium, and pyrrolidinium-2-one.

Specific examples of piperidinium cations include 1-propyl piperidinium, 1-pentyl piperidinium, 1,1-dimethyl piperidinium, 1-methyl-1-ethyl piperidinium, and 1-methyl-1-propyl piperidinium. Lydinium, 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-dibutylpiperidinium Lydinium, 1-butyl-1-pentylpiperidinium, 1-butyl-1-hexylpiperidinium, 1-butyl-1-heptylpiperidinium, etc. are mentioned.

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

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

Specific examples of imidazolium cations 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-methyl Imidazolium, 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, etc. can be mentioned.

Specific examples of tetrahydropyrimidinium cations include 1,3-dimethyl-1,4,5,6-tetrahydropyrimidinium, 1,2,3-trimethyl-1,4,5,6-tetrahydropyrimidi. nium, 1,2,3,4-tetramethyl-1,4,5,6-tetrahydropyrimidinium, 1,2,3,5-tetramethyl-1,4,5,6-tetrahydropyrimidi nium and the like can be mentioned.

Specific examples of dihydropyrimidinium cations 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, etc.

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

Specific examples of pyrazolium cations include 1-methylpyrazolium, 3-methylpyrazolium, 1-ethyl-2,3,5-trimethylpyrazolium, 1-propyl-2,3,5-trimethylpyrazolium, and 1-butyl. -2,3,5-trimethylpyrazolium, 1-(2-methoxyethyl)pyrazolium, etc. are mentioned. Specific examples of pyrazolinium cations include 1-ethyl-2-methylpyrazolinium.

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

The cation represented by formula (D) may be a symmetric cation or an asymmetric cation. As an ammonium cation with a symmetrical structure, R _l , R _m , R _n and R _o are the same alkyl group (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).

Representative examples of asymmetric ammonium cations include tetraalkylammonium cations in which three of R _l , R _m , R _n and R _o are the same and the remaining one is different. Specific examples include trimethylethylammonium, trimethylpropylammonium, trimethylbutylammonium, and trimethylpentylammonium. , trimethylhexyl ammonium, trimethylheptylammonium, trimethyloctylammonium, trimethylnonylammonium, trimethyldecylammonium, triethylmethylammonium, triethylpropylammonium, triethylbutylammonium, triethylpentylammonium, triethylhexylammonium, triethylheptylammonium. , triethyloctylammonium, triethylnonylammonium, triethyldecylammonium, tripropylmethylammonium, tripropylethylammonium, tripropylbutylammonium, tripropylpentylammonium, tripropylhexylammonium, tripropylheptylammonium, tripropyloctylammonium. , tripropylnonylammonium, tripropyldecylammonium, tributylmethylammonium, tributylethylammonium, tributylpropylammonium, tributylheptylammonium, tributylhexylammonium, tributylheptylammonium, tripentylmethylammonium, tripentylethylammonium. , tripentylpropylammonium, tripentylbutylammonium, tripentylhexylammonium, tripentylheptylammonium, trihexylmethylammonium, trihexylethylammonium, trihexylpropylammonium, trihexylbutylammonium, trihexylpentylammonium, trihexylpeptylammonium. , triheptylmethylammonium, triheptylethylammonium, triheptylpropylammonium, triheptylbutylammonium, triheptylpentylammonium, triheptylhexylammonium, trioctylmethylammonium, trioctylethylammonium, trioctylpropylammonium, trioctylbutylammonium. Asymmetric tetraalkylammonium, such as trioctylpentylammonium, trioctylhexylammonium, trioctylheptylammonium, trioctyldodecylammonium, trioctylhexadecylammonium, trioctyloctadecylammonium, trinonylmethylammonium, tridecylmethylammonium, etc. Cations can be mentioned.

Other examples of asymmetric ammonium cations include dimethyldiethylammonium, dimethyldipropylammonium, dimethyldibutylammonium, dimethyldipentylammonium, dimethyldihexylammonium, dimethyldiheptylammonium, dimethyldioctylammonium, dimethyldinonylammonium, and dimethyldidecyl. Ammonium, dipropyldiethylammonium, dipropyldibutylammonium, dipropyldipentylammonium, dipropyldihexylammonium, dimethylethylpropylammonium, dimethylethylbutylammonium, dimethylethylpentylammonium, dimethylethylhexylammonium, dimethylethylheptylammonium , dimethylethylnonylammonium, dimethylpropylbutylammonium, dimethylpropylpentylammonium, dimethylpropylheptylammonium, dimethylpropylheptylammonium, dimethylbutylheptylammonium, dimethylbutylheptylammonium, dimethylpentylhexylammonium, dimethylhexylheptylammonium, diethylmethylpropyl Ammonium, diethylmethylpentylammonium, diethylmethylheptylammonium, diethylpropylpentylammonium, dipropylmethylethylammonium, dipropylmethylpentylammonium, dipropylbutylhexylammonium, dibutylmethylpentylammonium, dibutylmethylhexylammonium, tetraalkylammonium cations such as methylethylpropylbutylammonium, methylethylpropylpentylammonium, and methylethylpropylhexylammonium; Ammonium cations containing a cycloalkyl group, such as trimethylcyclohexylammonium; Ammonium cations containing an alkenyl group such as diallyldimethylammonium, diallyldipropylammonium, diallylmethylhexylammonium, and diallylmethyloctylammonium; Triethyl(methoxyethoxyethyl)ammonium, dimethylethyl(methoxyethoxyethyl)ammonium, dimethylethyl(ethoxyethoxyethyl)ammonium, diethylmethyl(2-methoxyethyl)ammonium, diethylmethyl(methoxyethyl)ammonium ammonium cations containing an alkoxy group, such as toxyethoxyethyl)ammonium; Ammonium cations containing an epoxy group, such as glycidyltrimethylammonium; etc. can be mentioned.

Examples of the sulfonium cation with a symmetrical structure include trialkyl sulfonium cations in which R _l , 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). Examples of the asymmetric sulfonium cation include asymmetric trialkyl sulfonium cations such as dimethyldecylsulfonium, diethylmethylsulfonium, and dibutylethylsulfonium.

As a phosphonium cation with a symmetrical structure, R _l , R _m , R _n and R _o are the same alkyl group (for example, methyl group, ethyl group, butyl group, pentyl group, hexyl group, heptyl group, octyl group, nonyl group, de A tetraalkylphosphonium cation, which is any of the actual groups, is exemplified. As an asymmetric phosphonium cation, three of R _l , R _m , R _n and R _o are the same and the remaining one is a tetraalkylphosphonium cation different. Specific examples include trimethylpentylphosphonium, trimethylhexylphosphonium, and trimethylheptylphosphonium. , trimethyloctylphosphonium, trimethylnonylphosphonium, trimethyldecylphosphonium, triethylmethylphosphonium, tributylethylphosphonium, tributyl-(2-methoxyethyl)phosphonium, tripentylmethylphosphonium, trihexylmethyl Phosphonium, triheptylmethylphosphonium, trioctylmethylphosphonium, trinonylmethylphosphonium, tridecylmethylphosphonium, etc. can be mentioned. Other examples of asymmetric phosphonium cations include trihexyltetradecylphosphonium, dimethyldipentylphosphonium, dimethyldihexylphosphonium, dimethyldiheptylphosphonium, dimethyldioctylphosphonium, dimethyldinonylphosphonium, and dimethyldidecyl. asymmetric tetraalkylphosphonium cations, such as phosphonium; and sulfonium cations containing an alkoxy group, such as trimethyl(methoxyethoxyethyl)phosphonium and dimethylethyl(methoxyethoxyethyl)phosphonium.

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

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

The anion component of the ionic liquid is not particularly limited as long as it can be a salt of any of the cations disclosed herein that can be used as an ionic liquid. As specific examples, 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 CH( OH)COO ^- , and an anion represented by the following formula (F) can be mentioned.

Among them, hydrophobic anionic components tend to be difficult to bleed to the surface of the adhesive and are preferably used from the viewpoint of low contamination. Additionally, an anionic component containing a fluorine atom (for example, an anionic component containing a perfluoroalkyl group) is preferably used because an ionic compound with a low melting point can be obtained. Suitable examples of such anionic components include bis(perfluoroalkylsulfonyl)imide anion (e.g., (CF ₃ SO ₂ ) ₂ N ^- , (C ₂ F ₅ SO ₂ ) ₂ N ^- ), perfluoro Fluorine-containing anions such as Roalkylsulfonium anion (for example, CF ₃ SO ₃ ^- ) can be mentioned. The number of carbon atoms of the perfluoroalkyl group is usually preferably 1 to 3, and 1 or 2 is particularly preferable.

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

Such ionic liquids can be used commercially, or can be easily synthesized by known methods. The method for synthesizing the ionic liquid is not particularly limited as long as it allows the desired ionic liquid to be obtained. In general, the halide method, hydroxide method, acid ester method, complex formation method, and neutralization method, as described in the known document "Ionic Liquids - Frontiers and Future of Development" (published by CMC Publications), are used. .

(Other ionic compounds)

Additionally, as ionic compounds, in addition to the alkali metal salts and ionic liquids (for example, organic cation-anion salts) mentioned above, inorganic compounds such as ammonium chloride, aluminum chloride, copper chloride, ferrous chloride, ferric chloride, and ammonium sulfate. Salt can also be used. Additionally, the ionic compounds disclosed herein include those commonly referred to as ionic surfactants. Examples of ionic surfactants include cationic surfactants having cationic functional groups such as quaternary ammonium salts, phosphonium salts, sulfonium salts, pyridinium salts, and amino groups; Anionic surfactants having anionic functional groups such as carboxylic acid, sulfonate, sulfate, phosphate, and phosphite; Zwitterionic surfactants such as sulfobetaine and its derivatives, alkyl betaine and its derivatives, imidazoline and its derivatives, alkylimidazolium betaine and its derivatives; etc. can be mentioned. These may be used individually by 1 type, or may be used in combination of 2 or more types.

The amount of the ionic compound contained in the adhesive layer is not particularly limited, and can be approximately 1% by weight or more in the adhesive layer (based on the solid content of the adhesive composition), and from the viewpoint of improving conductivity, approximately 3% by weight or more. It is suitable, preferably approximately 6% by weight or more, more preferably approximately 9% by weight or more, and even more preferably approximately 12% by weight or more. The amount of ionic compound in the adhesive layer is usually approximately 40% by weight or less, and from the viewpoint of influence on adhesive properties and prevention of contamination of the adherend, approximately 30% by weight or less is appropriate, and is preferably approximately 25% by weight or less ( For example, approximately 20% by weight or less).

In addition, the adhesive layer disclosed herein uses, as a conductive agent, organic conductive materials such as polythiophene, polyaniline, polypyrrole, polyethyleneimine, and allylamine polymer, tin oxide, antimony oxide, indium oxide, cadmium oxide, and titanium oxide. , 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), etc. It may contain inorganic conductive substances such as metal particles or metal oxide particles. As a 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 conductive materials other than such ionic compounds (typically inorganic conductive materials) is limited to less than 20% by volume in the adhesive layer from the viewpoint of both adhesive strength and adherend separation and removability, transparency, etc. It is suitable, preferably less than 10 volume%, more preferably less than 3 volume%, and even more preferably less than 1 volume%. The technology disclosed herein can be preferably implemented in an aspect in which the pressure-sensitive adhesive layer does not substantially contain conductive substances other than ionic compounds.

In the technology disclosed herein, the form of the adhesive composition used to form the adhesive layer is not particularly limited. For example, an adhesive composition containing an adhesive component in an organic solvent (solvent-based adhesive composition), an adhesive composition in which the adhesive component is dispersed in an aqueous solvent (a water-dispersible adhesive composition, typically an aqueous emulsion-type adhesive composition). , adhesive compositions in which the adhesive component is dissolved in water (aqueous solution-type adhesive composition), solvent-free adhesive compositions (e.g., adhesive compositions that are cured by irradiation of active energy rays such as ultraviolet rays or electron beams, hot melt adhesives) composition), etc. In some preferred embodiments, the pressure-sensitive adhesive sheet has a pressure-sensitive adhesive layer formed of a solvent-based pressure-sensitive adhesive composition. The organic solvent contained in the solvent-type adhesive composition may be a single solvent containing any of, for example, toluene, xylene, ethyl acetate, hexane, cyclohexane, methylcyclohexane, heptane, and isopropyl alcohol, and may be any of these. A mixed solvent containing the main component may be used.

In the technology disclosed herein, the adhesive composition (preferably a solvent-based adhesive composition) used to form the adhesive layer is appropriately crosslinked with a polymer (typically a polymer containing an oxyalkylene structural unit) contained in the composition. It is preferable to adopt one that is configured to do so. As a specific crosslinking means, a crosslinking origin is introduced into the polymer by copolymerizing a monomer having an appropriate functional group (hydroxyl group, carboxyl group, etc.), and a compound (crosslinking agent) that can react with the functional group to form a crosslinked structure is added to the polymer. A method of reacting can be preferably adopted.

The type of crosslinking agent used is not particularly limited, and includes, for example, isocyanate-based crosslinking agents, epoxy-based crosslinking agents, oxazoline-based crosslinking agents, aziridine-based crosslinking agents, melamine-based crosslinking agents, peroxide-based crosslinking agents, urea-based crosslinking agents, metal alkoxide-based crosslinking agents, and metal chelates. Examples include cross-linking agents, metal salt-based cross-linking agents, carbodiimide-based cross-linking agents, and amine-based cross-linking agents. These crosslinking agents can be used individually or in combination of two or more types. Among them, isocyanate-based crosslinking agents are preferable.

The amount of crosslinking agent used can be appropriately selected depending on the type, structure, molecular weight, etc. of the polymer, and adhesive properties such as adhesive force and peelability. For example, by increasing the amount of crosslinking agent used to a predetermined amount or more, the cohesion of the adhesive can be improved and the adhesive can be prevented from remaining on the adherend. From that viewpoint, it is appropriate that the amount of crosslinking agent used per 100 parts by weight of the polymer (typically a polymer containing oxyalkylene structural units) is approximately 0.01 part by weight or more, preferably approximately 0.1 part by weight or more (e.g. approximately 0.2 parts by weight or more). In addition, the amount of the crosslinking agent used is preferably approximately 10 parts by weight or less (for example, approximately 5 parts by weight or less). In an embodiment of using an isocyanate-based crosslinking agent as a crosslinking agent, the amount of the isocyanate-based crosslinking agent used is appropriate to be approximately 0.5 parts by weight or more per 100 parts by weight of the polymer (typically a polymer containing an oxyalkylene structural unit). is approximately 1 part by weight or more, more preferably approximately 1.5 parts by weight or more (for example, approximately 2 parts by weight or more), and may be approximately 3 parts by weight or less.

The pressure-sensitive adhesive composition may further include a catalyst for the purpose of promoting various reactions related to pressure-sensitive adhesive layer formation. Such a catalyst may be called a crosslinking catalyst or a curing catalyst. The type of catalyst can be appropriately selected depending on the type of compound (crosslinking agent, etc.) used. Catalysts include, for example, iron-containing compounds such as iron acetylacetonate and iron 2-ethylhexanoate, dioctyltin dilaurate, dibutyltin dilaurate, dibutyltin diacetylate, dibutyltin diacetylacetonate, tetra- tin (Sn)-containing compounds such as n-butyltin and trimethyltin hydroxide; titanium-containing compounds such as tetraisopropyl titanate and tetra-n-butyl titanate; Organometallic compounds such as; Nitrogen (N)-containing compounds such as amines such as N,N,N',N'-tetramethylhexanediamine and triethylamine, and imidazoles; Basic compounds such as lithium hydroxide, potassium hydroxide, and sodium methylate; Acidic compounds such as p-toluenesulfonic acid, trichloroacetic acid, phosphoric acid, monoalkyl phosphoric acid, dialkyl phosphoric acid, and phosphoric acid ester of β-hydroxyethyl acrylate; etc. are exemplified. These can be used individually or in combination of two or more types. The amount of catalyst contained in the 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 practiced in an aspect that uses an adhesive layer containing a polymer different from the oxyalkylene structural unit-containing polymer (i.e., a polymer that does not contain an oxyalkylene structural unit). In an embodiment in which the pressure-sensitive adhesive layer contains an oxyalkylene structural unit-containing polymer, it may also contain the above-described oxyalkylene structural unit-free polymer in addition to the oxyalkylene structural unit-containing polymer. As the polymer not containing an oxyalkylene structural unit, any of the various polymers exemplified above that do not contain an oxyalkylene structural unit can be used. The content of the oxyalkylene structural unit-free polymer in the adhesive layer is set according to the target adhesive properties and conductivity, and is not limited to a specific range. For example, in the adhesive layer (out of the solid content of the adhesive composition), it can be approximately 70% by weight or less, and approximately 50% by weight or less is appropriate, and the effect of other adhesive layer components such as polymers containing oxyalkylene structural units From the viewpoint of sufficiently exhibiting, approximately 30% by weight or less is preferable, approximately 10% by weight or less is more preferable, and approximately 3% by weight or less (for example, 0 to 1% by weight) is further preferable.

Various conventionally known additives can also be blended into the adhesive composition as needed. Examples of such additives include surface lubricants, leveling agents, antioxidants, preservatives, light stabilizers, ultraviolet absorbers, polymerization inhibitors, and silane coupling agents. Additionally, a tackifying resin or a peeling regulator may be added. Additionally, the adhesive layer disclosed herein may or may not contain an alkylene oxide compound such as polyethylene glycol or polypropylene glycol. When synthesizing an adhesive polymer by emulsion polymerization, an emulsifier or chain transfer agent (which can also be considered a molecular weight regulator or polymerization degree regulator) is preferably used.

(Method of forming adhesive layer)

The pressure-sensitive adhesive layer in the technology disclosed herein can be formed, for example, by applying the pressure-sensitive adhesive composition as described above directly to a base film and drying or curing it (direct method). Alternatively, it is also possible to form an adhesive layer on the surface by applying the adhesive composition to the surface (release surface) of the release liner and drying or curing it, and the adhesive layer thus formed is bonded to the base film to form the adhesive layer. You may form it by the method of transferring an adhesive layer (transfer method). From the viewpoint of anchoring properties of the adhesive layer, the direct method can usually be preferably adopted. When applying (typically applying) the adhesive composition, adhesive sheets are used, such as roll coating, gravure coating, reverse coating, roll brush coating, spray coating, air knife coating, or die coater coating. In the field, various conventionally known methods can be appropriately employed. Drying of the adhesive composition can be performed under heating (for example, by heating to about 60°C to 150°C) as needed. As a means for curing the adhesive composition, ultraviolet rays, laser rays, α-rays, β-rays, γ-rays, X-rays, electron beams, etc. can be appropriately employed.

(Thickness of adhesive layer)

Although not particularly limited, the thickness of the adhesive layer can be, for example, approximately 1 μm or more, and from the viewpoint of adhesion reliability to the adherend, approximately 3 μm or more is appropriate, and is preferably approximately 5 μm. or greater (for example, approximately 7㎛ or greater). In addition, the thickness can be, for example, approximately 100 μm or less, and from the viewpoint of adherend separation and removability, it is appropriate to set it to approximately 50 μm or less, and preferably approximately 30 μm or less (e.g., approximately 20 μm). below). Since the adhesive layer disclosed herein can exhibit good conductivity without using a conductive agent such as metal particles, the adhesive layer showing a surface resistance value of a predetermined value or less can be formed with a relatively thin thickness.

<Adhesive composition>

As described above, the adhesive layer of the adhesive sheet disclosed herein is formed of an adhesive composition. Accordingly, the technology disclosed herein includes an adhesive composition. According to the adhesive composition, it is possible to achieve both a predetermined or higher conductivity and an adhesive force within a predetermined range, for example, it has a surface resistance value of ^1.0 An adhesive that falls within the range can be suitably realized. The pressure-sensitive adhesive composition disclosed herein may contain an oxyalkylene structural unit as described above. The adhesive composition according to some preferred embodiments includes a polymer having an oxyalkylene structural unit and/or an oligomer or monomer for forming the polymer, and may also contain an ionic compound or various additive components as optional components. You can. Since the details of the composition (specific examples and content of components) are the same as above, the description will not be repeated.

<Base layer>

In an adhesive sheet provided with a single-sided adhesive type or double-sided adhesive type substrate, various substrate films can be used as a substrate layer that supports (backs) the adhesive layer. As the base film, resin films, paper, cloth, rubber sheets, foam sheets, metal foils, composites thereof, etc. can be used. Among them, a resin film can be preferably employed. The resin film referred to here is typically a non-porous resin sheet, and is a concept that is distinct from, for example, non-woven fabric (i.e., does not include non-woven fabric), and is usually formed by molding various resin materials into a film shape.

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 chloride-based resin film; Vinyl acetate-based resin film; polyimide resin film; polyamide-based resin film; fluororesin film; cellophane; etc. can be mentioned. The resin film may have a single-layer structure or may have a structure in which a plurality of layers with different compositions are laminated. Usually, a resin film with a single-layer structure can be preferably employed.

Examples of paper include Japanese paper, kraft paper, glassine paper, fine paper, synthetic paper, and top coat paper. Examples of fabric include woven fabrics and non-woven fabrics made of various fibrous materials alone or mixed. Examples of the fibrous materials include cotton, staple fiber, Manila hemp, pulp, rayon, acetate fiber, polyester fiber, polyvinyl alcohol fiber, polyamide fiber, and polyolefin fiber. Examples of rubber sheets include natural rubber sheets, butyl rubber sheets, and the like. Examples of foam sheets include foamed polyurethane sheets, foamed polychloroprene rubber sheets, and the like. Examples of 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 suitably approximately 50 MPa or more from the viewpoint of having a predetermined rigidity and stably supporting the adherend. Additionally, from the viewpoint of bondability, handling, etc., it is appropriate that the elastic modulus is approximately 50,000 MPa or less. The elastic modulus of the base film can be set by selecting an optimal material to have a predetermined rigidity and flexibility depending on the purpose of use. In some embodiments, the elastic modulus of the base film (for example, a soft vinyl chloride resin film) is approximately 100 MPa or more (typically approximately 150 MPa or more, for example, approximately 200 MPa or more), and is also approximately 1,000 MPa. or less (typically less than or equal to approximately 600 MPa, for example less than or equal to approximately 300 MPa). In several other embodiments, the elastic modulus of the base film (e.g., olefin resin film) is approximately 300 MPa or more (typically 400 MPa or more) and approximately 10,000 MPa or less (typically 3,000 MPa or less, e.g. For example, it may be 1,000 MPa or less). In some other embodiments, the elastic modulus of the base film (for example, a polyester resin film) is approximately 500 MPa or more (typically 1,000 MPa or more, for example, 3,000 MPa or more), and approximately 30,000 MPa or less. (Typically, it may be 15,000 MPa or less, for example, 7,000 MPa or less).

In addition, the elastic modulus of the base film (typically a resin film) is determined from the resin film along any one direction (for example, MD (Machine Direction) or TD (Transverse Direction; a direction perpendicular to MD), preferably MD). It is the tensile modulus calculated from the linear regression of the stress-strain curve obtained by cutting a test piece of a predetermined width and stretching the test piece in one direction at room temperature (23°C) in accordance with JIS K7161 at a tensile speed of 300 mm/min. .

As the base film (typically a resin film), one that has transparency is preferably employed from the viewpoint of inspectability beyond the adhesive sheet. Therefore, the resin film preferably has transparency such that the total light transmittance in the visible light wavelength range is approximately 70% or more. A transparent resin film having a total light transmittance of 80% or more (for example, 85% or more) is more preferable. In addition, the upper limit of the total light transmittance is ideally 100%, but for practical purposes, as long as it has a total light transmittance of about 99% or less (typically 97% or less, for example, 95% or less), it can be used as a transparent resin film. It can be used preferably. As the value of the total light transmittance, the manufacturer's notarized value can be adopted. If there is no certified value, the value measured based on JIS K 7361-1 can be adopted.

Various additives such as fillers, antioxidants, ultraviolet absorbers, antistatic components, plasticizers, lubricants, and colorants (pigments, dyes, etc.) may be blended in the base material layer as needed. The surface of the base material layer on the adhesive layer side may be subjected to known or customary surface treatments such as corona discharge treatment, plasma treatment, ultraviolet irradiation treatment, acid treatment, alkali treatment, or application of a primer. Such surface treatment may be, for example, a treatment to improve the anchoring properties of the adhesive layer. In addition, when the single-sided adhesive sheet is wound and the surface of the adhesive layer is brought into contact with the back of the base material layer, silicone-based , a peeling treatment using a long-chain alkyl-based, fluorine-based, etc. peeling treatment agent may be performed. By performing the peeling treatment, effects such as facilitating the rewinding of the wound body in which the adhesive sheet is wound into a roll are obtained.

The thickness of the base material layer can be appropriately selected in consideration of the use, purpose, use form, etc. of the adhesive sheet. From workability such as strength and handleability, a base film with a thickness of approximately 10 ㎛ or more is usually suitable, preferably approximately 15 ㎛ or more, more preferably approximately 20 ㎛ or more, even more preferably 30 ㎛ or more (e.g. For example, 35㎛ or more). In addition, from the viewpoint of cost, testability, etc., the thickness of the base material layer is usually approximately 1 mm or less, and approximately 200 μm or less is appropriate, preferably approximately 150 μm or less, more preferably approximately 100 μm or less, and further. Preferably it is approximately 75㎛ or less.

<Sublayer>

In some embodiments, an undercoat layer is provided on the surface of the base layer on the adhesive layer side. In other words, an undercoat layer is disposed between the base material layer and the adhesive layer. The undercoating layer may have a single-layer structure or a multi-layer structure of two or more layers. The material (undercoat agent) forming the undercoat layer is not particularly limited and includes urethane-based resin, polyester-based resin, acrylic resin, acrylic-urethane-based resin, acrylic-styrene-based resin, polyamide-based resin, melamine-based resin, and olefin-based resin. One or two or more of resins, polystyrene-based resins, epoxy-based resins, phenol-based resins, isocyanurate-based resins, polyvinyl acetate-based resins, etc. may be used. When forming an acrylic adhesive layer on a resin film substrate, a polyester-based, urethane-based, or acrylic-based primer is preferable, and when providing an acrylic-based adhesive layer on a polyester-based substrate layer such as a PET film, a polyester-based primer is preferable. Layers are particularly preferred.

<Conductive undercoat layer>

In some preferred embodiments, the undercoat layer disposed between the base material layer and the adhesive layer preferably contains a conductive agent. As a result, the conductivity of the adhesive sheet is improved, and the electrical conductivity of the adherend is improved. Hereinafter, the undercoat layer containing a conductive agent is also referred to as a conductive undercoat layer. The conductive undercoating layer may have a single-layer structure or a multi-layer structure of two or more layers. In an embodiment in which a multi-layered undercoat layer is disposed between the base material layer and the adhesive layer, it is preferable that at least one layer (typically at least one layer including a layer in contact with the adhesive layer) is a conductive undercoat layer. As a conductive agent, organic conductive materials such as polythiophene, polyaniline, polypyrrole, polyethyleneimine, and allylamine polymer, gold, silver, copper, platinum, palladium, aluminum, nickel, chromium, titanium, iron, cobalt, tin, Metals such as magnesium and tungsten, alloys of these metals, and metal oxides of indium, tin, zinc, gallium, antimony, zirconium, and cadmium (tin oxide, antimony oxide, indium oxide, cadmium oxide, titanium oxide, zinc oxide, ITO) Inorganic conductive materials such as metal particles such as (indium oxide/tin oxide), ATO (antimony oxide/tin oxide), copper iodide, metal oxide particles, or metal compound particles may be used. As a conductive agent, inorganic particles such as glass An inorganic composite conductive material coated with a metal such as silver, or an organic-inorganic composite conductive material coated with an organic material such as a conductive polymer can be used, for example. The ionic compounds described above can also be used. These can be used individually or in combination of two or more.

In the aspect in which the undercoat layer is disposed, examples of conductive polymers that can be included in the undercoat layer include polythiophene and polyaniline. As polythiophene, Mw in terms of polystyrene is preferably 40×10 ⁴ or less, and more preferably 30×10 ⁴ or less. As polyaniline, Mw is preferably 50×10 ⁴ or less, and more preferably 30×10 ⁴ or less. Additionally, the Mw of these conductive polymers is usually preferably 0.1×10 ⁴ or more, and more preferably 0.5×10 ⁴ or more. In addition, in this specification, polythiophene refers to a polymer of unsubstituted or substituted thiophene. A suitable example of the substituted thiophene polymer in the technology disclosed herein is poly(3,4-ethylenedioxythiophene).

In some preferred embodiments, the conductive base layer may include polystyrene sulfonate (PSS) as a dopant (e.g., a dopant of a thiophene-based polymer). In some embodiments, a conductive undercoat layer is formed using a composition for forming an undercoat layer containing an aqueous polythiophene solution containing PSS (PSS may be added as a dopant to polythiophene). This aqueous solution may contain polythiophene:PSS at 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. In addition, when using a polythiophene aqueous solution containing PSS, the total amount of polythiophene and PSS is 5 parts by weight or more (usually 10 parts by weight or more, for example, 25 parts by weight or more) per 100 parts by weight of binder. ) is appropriate, and is preferably 40 parts by weight or more. In addition, the total amount of the polythiophene and PSS is suitably 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, based on 100 parts by weight of the binder. It may be less than (for example, 60 parts by weight or less).

From the viewpoint of improving conductivity, the amount of organic conductive material (typically a conductive polymer) used can be approximately 10 parts by weight or more per 100 parts by weight of the binder contained in the undercoat layer, and is usually 25 parts by weight or more. It is appropriate, preferably 40 parts by weight or more. Considering changes in properties such as the compatibility of the organic conductive material (typically a conductive polymer) in the undercoating layer and, in turn, a decrease in transparency due to a decrease in compatibility, the amount of organic conductive material (typically a conductive polymer) used must be , it is appropriate to set it to 200 parts by weight or less (for example, 150 parts by weight or less) with respect to 100 parts by weight of binder, and preferably 120 parts by weight or less (for example, 100 parts by weight or less). It is also possible to set the amount of the organic conductive material (typically a conductive polymer) used to 80 parts by weight or less (for example, 60 parts by weight or less) per 100 parts by weight of the binder.

The total amount of the conductive agent in the conductive undercoat layer (the total amount of all conductive agents including the organic conductive material, the inorganic conductive material, and the organic-inorganic composite conductive material) is approximately 5% by weight of the undercoat layer, depending on the desired conductivity. (For example, approximately 10% by weight or more). It is appropriate to set it to approximately 30% by weight or more, and may exceed, for example, 50% by weight. The upper limit of the total amount of conductive agent in the conductive undercoat layer is not particularly limited, and is suitably approximately 90% by weight or less (e.g., 80% by weight or less), taking into account adhesion to the base layer or adhesive layer, transparency, etc. Therefore, it may be approximately 40% by weight or less (for example, approximately 30% by weight or less).

The conductive undercoat layer may include a binder in addition to the conductive agent described above. As a binder that can be included in the conductive undercoat layer, the materials for forming the undercoat (undercoat agent) described above can be used without particular restrictions. Among them, use of polyester resin is preferable. The proportion of the binder in the entire conductive undercoat layer can be, for example, approximately 30% by weight or more, and is preferably approximately 40% by weight or more (for example, approximately 50% by weight or more). In addition, it is appropriate that the proportion of the binder is less than 90% by weight (less than 80% by weight) in consideration of conductivity and the like.

Additionally, in some embodiments, the undercoat layer contains a crosslinking agent. As the crosslinking agent, crosslinking agents such as melamine-based, isocyanate-based, and epoxy-based crosslinking agents used for crosslinking general resins can be appropriately selected and used. Thereby, anchoring properties to the base layer and adhesion to the adhesive layer can be favorably achieved. In some preferred embodiments, the cross-linking agent includes a melamine-based cross-linking agent.

If necessary, the undercoating layer may contain additives such as antioxidants, colorants (pigments, dyes, etc.), rheology modifiers (thixotropic agents, thickeners, etc.), film-forming aids, surfactants (defoaming agents, dispersants, etc.), and preservatives. there is.

The undercoat layer is made by applying a liquid composition (coating material for undercoat layer formation) in which the above-mentioned resin components and optionally used additives are dispersed or dissolved in an appropriate solvent using a known or customary coater such as a gravure roll coater or reverse roll coater. It can be suitably formed by applying it to a base film and, if necessary, by a method including drying or curing treatment. From the viewpoint of forming a thin and uniform layer, the NV (non-volatile matter) of the coating material can be, for example, 5% by weight or less (typically 0.05 to 5% by weight). As a solvent that can form the coating material, any 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) is preferable.

In some other embodiments, the conductive undercoat layer may be, for example, a layer composed of the above-described metal or metal oxide. 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 ATO layer is preferable from the viewpoint of transparency. As ITO, one containing approximately 80 to 99% by weight of indium oxide and approximately 1 to 20% by weight of tin oxide is preferably used. The metal layer or metal oxide layer as the conductive undercoat layer may be a metal vapor deposition layer such as aluminum, a plating layer, or the like.

The thickness of the undercoat layer in the technology disclosed herein is not particularly limited, and is usually approximately 0.01 μm or more, and from the viewpoint of appropriately expressing the function of the undercoat layer, it is appropriate and preferably approximately 0.05 μm or more. may be approximately 0.1 μm or more (for example, approximately 0.2 μm or more). The upper limit of the thickness of the undercoating layer can be approximately 50 ㎛ or less (e.g. approximately 10 ㎛ or less), and from the viewpoint of transparency etc., approximately 3 ㎛ or less is appropriate, and is preferably approximately 1 ㎛ or less (e.g. For example, approximately 0.6㎛ or less).

<Release liner>

The adhesive sheet disclosed herein has a form in which a release liner is bonded to the adhesive surface (the side of the adhesive layer attached to the adherend) for the purpose of protecting the adhesive surface (adhesive sheet with a release liner) as needed. form). The release liner is not particularly limited, and includes, for example, a release liner in which the surface of a liner base material such as a resin film or paper has been subjected to a release treatment, a fluorine-based polymer (polytetrafluoroethylene, etc.), or a polyolefin-based resin (polyethylene, polypropylene, etc.) ), a release liner containing a low-adhesion material, etc. can be used. For the peeling treatment, for example, a peeling treatment agent such as silicone-based, fluorine-based, long-chain alkyl-based, fatty acid amide-based, or silica powder can be used. In some embodiments, a resin film (for example, a polyester film) that has been subjected to a release treatment can be preferably used as a release liner. The thickness of the release liner can be, for example, approximately 5 μm to 200 μm, and is usually preferably approximately 10 μm to 100 μm.

<Total thickness of adhesive sheet>

The total thickness of the adhesive sheet disclosed herein (which may include an adhesive layer, a base layer, and an undercoat layer, but does not include a release liner) is not particularly limited, and is suitably in the range of approximately 5 to 1000 μm. 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, etc. In addition, from the viewpoint of handling, etc., the total thickness of the adhesive sheet is preferably approximately 30 μm or more, and is preferably approximately 150 μm or less (for example, 120 μm or less), and may be approximately 80 μm or less. .

<Characteristics of adhesive sheet>

The adhesive sheets of some typical embodiments have a 180-degree peel strength (adhesive strength vs. SUS plate adhesive strength) to a stainless steel sheet measured under conditions of a peel angle of 180 degrees and a speed of 300 mm/min in an environment of 23°C. It is characterized by being within the range of 0.01 to 4.0 N/20 mm. According to the adhesive sheet exhibiting the above-described predetermined range of adhesive strength, it is possible to secure an adherend such as a conductive small piece with good adhesion reliability, and it can also be separated from the adherend well after use, thereby preventing damage to the adherend. . From the viewpoint of adhesion reliability, the adhesive force may be approximately 0.02 N/20 mm or more, approximately 0.03 N/20 mm or more, approximately 0.05 N/20 mm or more, or approximately 0.08 N/20 mm or more. From the viewpoint of the separation and removability of 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 is preferably approximately 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 adhesion to the SUS plate is measured by the method described in the Examples described later. In addition, the pressure-sensitive adhesive sheet disclosed in this specification includes aspects in which the adhesive strength is not limited, and in such aspects, the pressure-sensitive adhesive sheet is not limited to having the adhesive strength.

The haze value of the adhesive sheet is not particularly limited, and may be about 80% or less, for example. When inspecting an adherend through an adhesive sheet, the adhesive sheet needs to have adequate transparency. From that viewpoint, it is appropriate that the haze value of the adhesive sheet is approximately 50% or less (for example, approximately 30% or less), preferably approximately 10% or less, more preferably approximately 3% or less, even more preferably is approximately 1% or less (for example, less than 0.1%). The haze value is measured by the method described in the Examples described later.

<Use>

The use of the adhesive sheet disclosed herein is not particularly limited, and it can be widely used in various applications where it is attached to an adherend and then peeled off, taking advantage of adhesion reliability during attachment and good separation and removal properties from the adherend. Such uses include temporary fixation sheets and protective sheets. Additionally, for example, it can be suitably used as a process material that is fixed to and peeled off from an adherend in the manufacturing process of electronic devices and electronic components.

In addition, 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 suitably used as a conductive adhesive member in various electronic devices. The conductive adhesive sheet can also be used as an electromagnetic wave shield for electronic devices and cables, and for preventing static electricity.

The adhesive sheet according to several preferred embodiments can be used as an adhesive sheet that separably holds a plurality of conductive small pieces. The conductive small pieces referred to here include metal chips, semiconductor chips, and organic conductive chips used in various applications. For example, semiconductors such as light-emitting semiconductor chips (typically LED chips) used in electronic products with a display function, etc. It could be a chip. The number of conductive small pieces disposed on one adhesive sheet is 1 or 2 or more, and in some embodiments, the conductive small pieces are formed by dicing a conductive wafer. It can be a small piece (more than 10,000, more than 100,000). The size of each small piece is not particularly limited, and may be, for example, approximately a square with a side of 4 to 5 mm or smaller. In the adhesive sheet disclosed herein, by arranging and fixing a plurality of such conductive small pieces on the adhesive layer, it is possible to energize all the conductive small pieces on the adhesive at the same time, and the conductive small pieces can be inspected collectively by applying electricity. . Therefore, the adhesive sheet disclosed herein can also be called an adhesive sheet for energization inspection of conductive small pieces. The above-mentioned energization method is a method that fundamentally solves the technical and time limitations of individual inspection using probe pins that were previously required, and can be a means of realizing product miniaturization and high performance while improving productivity. The pressure-sensitive adhesive sheet disclosed herein can be suitably used for such purposes, so its practical advantages are great.

<Method for manufacturing tested conductive small pieces>

Based on the above description, according to the present specification, a method for manufacturing an inspected conductive small piece (for example, a semiconductor chip) is provided. This method may also be an inspection method for conductive small pieces. The method includes a step of preparing an adhesive sheet on which a plurality of conductive small pieces to be inspected are fixed (preparation step). In this preparation process, the plurality of conductive small pieces to be inspected are detachably fixed to the surface of the adhesive layer. As the adhesive sheet, one having an adhesive layer having conductivity is used. The method also includes a step (inspection process) of energizing at least a portion (for example, all) of a plurality of conductive pieces to be inspected through an adhesive layer and inspecting the conductive pieces to be inspected in the energized state. According to this method, simultaneous energization inspection of a plurality of conductive small pieces is possible. Additionally, this method may further include, typically, before the inspection process, a step of bringing the surface of the plurality of conductive small pieces to be inspected, opposite to the surface fixed to the corresponding adhesive layer, into contact with a conductive material. As a result, in the inspection process, it is possible to energize all of the conductive small pieces to be inspected through the adhesive layer and the conductive material. Below, it is described in detail.

First, in this method, an adhesive sheet to which a plurality of conductive small pieces to be inspected are 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 a plurality of conductive small pieces from the conductive wafer. In this way, it is possible to prepare an adhesive sheet on which a plurality of conductive small pieces to be inspected are fixed. As the adhesive sheet, the adhesive sheet disclosed herein is preferably used, but it is not limited to this, and any adhesive sheet having a known or common conductive adhesive layer may be used. The processing process of a conductive wafer (eg, a semiconductor wafer) may include a dicing process or an expansion process of the conductive wafer. The dicing process may be, for example, a process of breaking the wafer into pieces after laser dicing using a laser beam or the like. Then, each small piece on the adhesive layer is arranged at a predetermined interval by expansion (expansion process) of the adhesive sheet holding the small piece.

In several other embodiments, a plurality of conductive small pieces formed using a known or commonly used adhesive sheet for dicing or an adhesive sheet for expansion are transferred onto the adhesive layer of an adhesive sheet having a conductive adhesive layer, thereby forming a plurality of conductivity objects to be inspected. Prepare an adhesive sheet on which the small piece is fixed. As the conductive adhesive sheet, the 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 part (preferably all) of the plurality of conductive small pieces to be inspected are brought into contact with the conductive material. As the conductive material, the adhesive sheet (conductive adhesive sheet) disclosed herein is preferably used. Alternatively, a known or commonly used conductive adhesive sheet may be used. As a conductive material, it is also possible to use a metal plate conventionally used in conduction inspection of semiconductor chips and the like. Since the conductive material is usually placed on the opposite side of the inspection surface, transparency is not required.

Next, a terminal for conduction inspection, such as a probe pin, is connected to the adhesive layer of the adhesive sheet to enable conduction, and another terminal for conduction inspection (such as a probe pin) is connected to the conductive material to enable conduction. In this state, an electric current flows through the adhesive layer and the conductive material. As a result, at least some (preferably all) of the plurality of conductive small pieces to be inspected can be energized simultaneously and collectively. In this way, an energization test can be performed.

Figure 3 is a schematic cross-sectional view illustrating the energization inspection related to the present method. In Fig. 3, symbols 101, 110, and 120 represent the adhesive sheet, base material layer, and adhesive layer (conductive adhesive layer) disclosed herein, respectively, and symbol 201 represents a conductive material. In this embodiment, the adhesive sheet disclosed herein is used as the conductive material 201, and the conductive material (adhesive sheet) 201 includes the base layer 210 and the adhesive layer (conductive adhesive layer) 220. Equipped with The plurality of conductive small pieces 150 fixed to the surface of the adhesive layer 120 of the adhesive sheet 101 have the surface opposite to the surface fixed to the adhesive layer 120 covered with the adhesive of the conductive material (adhesive sheet) 201. It is in contact (specifically, adhesively fixed) to the surface of the layer 220. Specifically, as shown, a plurality of conductive small pieces 150 are arranged in a separated state on the surface of the adhesive layer 120. The surface of the plurality of conductive small pieces 150 opposite to the fixation surface with the adhesive layer 120 is covered with a conductive material (adhesive sheet) 201, whereby each conductive small piece 150 , both sides of which contact (specifically, adhere) the surface of the adhesive layer 120 of the adhesive sheet 101 and the surface of the adhesive layer 220 of the conductive material (adhesive sheet) 201, respectively, and the adhesive sheet 101 ) and is in a state in which electricity can be passed through the conductive material 201. Moreover, in FIG. 3, P is a terminal (probe pin) for energization inspection, and C is a camera for inspection. In addition, only a few representative conductive pieces 150 in the drawing are assigned symbols. Additionally, the conductive small piece 150 in this embodiment is a light-emitting semiconductor chip, and has electrodes on both sides that contact the adhesive layers 120 and 220.

Although the inspection camera C is used in this embodiment, the inspection is not limited to this, and may be inspection by various optical inspection means or visual inspection. Using inspection means such as inspection camera C, a plurality of conductive small pieces 150 energized at the same time can be inspected beyond the adhesive sheet 101 (specifically, this may be an inspection of the light emission intensity or light wavelength of the light-emitting semiconductor chip, etc.) ), it is possible to perform defective product determination, grading, etc. on the plurality of conductive small pieces 150 all at once. After completion of the inspection, each conductive small piece is separated and removed from the adhesive sheet 101 and the conductive material 201, and is then shipped as a product. As for other specific details regarding the above method, they are as described in this specification, so redundant description will be omitted.

Matters disclosed by this specification include the following.

(1) An adhesive sheet including 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 in the range of 0.01 to 4.0N/20mm.

(2) an adhesive sheet including an adhesive layer,

The adhesive layer includes a polymer having an oxyalkylene structural unit,

The oxyalkylene structural unit includes a polyoxyalkylene unit in which the mole number of oxyalkylene is greater than 2,

An adhesive sheet wherein the polymer contains oxyalkylene structural units in a proportion of 35% by weight or more.

(3) The adhesive sheet according to (1) or (2) above, wherein the haze value is 50% or less.

(4) The adhesive sheet according to any one of (1) to (3) above, wherein the adhesive layer contains an oxyalkylene structural unit.

(5) The pressure-sensitive adhesive sheet according to (4) above, wherein the pressure-sensitive adhesive layer contains a polymer having the oxyalkylene structural unit.

(6) The pressure-sensitive adhesive sheet according to (5) above, wherein the polymer having the oxyalkylene structural unit has the oxyalkylene structural unit in a side chain.

(7) The pressure-sensitive adhesive sheet according to any one 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 adhesive sheet according to any one of (1) to (7) above, wherein the adhesive layer contains an ionic compound.

(9) The adhesive sheet according to any one of (1) to (8) above, further comprising a base layer, wherein the adhesive layer is provided on at least one side of the base layer.

(10) The adhesive sheet according to (9) above, wherein the base layer is composed of a resin film with an elastic modulus of 50 MPa or more.

(11) The adhesive sheet according to (9) or (10) above, wherein an undercoating layer is disposed between the base layer and the adhesive layer.

(12) A process of preparing an adhesive sheet on which a plurality of conductive small pieces to be inspected (for example, semiconductor chips) are fixed - where the adhesive sheet has an adhesive layer having conductivity, and the plurality of conductive small pieces to be inspected are is detachably fixed to the surface of the adhesive layer - and,

A method for manufacturing inspected conductive small pieces, comprising the step of passing electricity to at least a portion of the plurality of conductive small pieces to be inspected through the adhesive layer, and inspecting the conductive small pieces to be inspected in the energized state.

(13) The method according to (12) above, further comprising a step of bringing the surface of the plurality of conductive small pieces to be inspected opposite to the fixing surface of the adhesive layer to a conductive material before the inspection step.

(14) Before the step of preparing the adhesive sheet on which the conductive small pieces are fixed, a step of fixing a conductive wafer to the adhesive sheet, and a step of processing the conductive wafer to form a plurality of conductive small pieces from the conductive wafer. The method according to (12) or (13) above, further comprising:

(15) The method according to (14) above, wherein the conductive wafer processing step includes a conductive wafer dicing step and may optionally include an expansion step.

(16) The method according to (12) or (13), comprising a step of fixing the plurality of conductive pieces to the adhesive sheet before the step of preparing the adhesive sheet to which the conductive pieces are fixed.

(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 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 inspection process of the conductive small piece to be inspected includes inspection beyond the adhesive sheet by inspection means such as a camera or visual inspection (for example, inspection of the luminous state of a light-emitting semiconductor element), from (12) to above. The method described in any one of (19).

(21) comprising polymers containing oxyalkylene structural units,

The oxyalkylene structural unit includes a polyoxyalkylene unit in which the mole number of oxyalkylene is greater than 2,

An 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) above, wherein the polymer having the oxyalkylene structural unit has the oxyalkylene structural unit in a side chain.

(23) The pressure-sensitive adhesive composition according to (21) or (22) above, wherein the ratio of the oxyalkylene structural unit is 20 to 95% by weight based on solid content.

(24) The pressure-sensitive adhesive composition according to any one of (21) to (23) above, comprising an ionic compound.

(25) The pressure-sensitive adhesive composition according to any one of (21) to (24) above, wherein the polymer having the oxyalkylene structural unit is an acrylic polymer.

Hereinafter, several examples related to the present invention will be described, but it is not intended to limit the present invention to these specific examples. In addition, “part” and “%” in the following description are based on weight unless otherwise specified.

<Evaluation method>

[adhesiveness]

The adhesive sheet was cut to a size of 20 mm wide x 120 mm long to produce a measurement sample. This measurement sample was placed on a stainless steel plate (SUS430BA plate) ultrasonically cleaned in toluene at a linear pressure of 78.5 N/cm and a speed of 0.3 m/cm. Join under the following conditions. Bonding is performed in an atmosphere of 23°C and 50%RH. After standing for 30 minutes in the same environment, the measurement sample was peeled from the stainless steel plate using a tensile tester under the conditions of a tensile angle of 180 degrees and a speed of 0.3 m/min, and the peeling strength at that time [N/20 mm] was used as the adhesive force. Measure. As a tensile tester, the product name "AUTOGRAPH AG-IS" manufactured by Shimadzu Seisakusho Co., Ltd. or its equivalent product can be used. In addition, when the measurement sample is a double-sided adhesive sheet (for example, an inorganic adhesive sheet), the non-measurement side is backed with a PET film with a thickness of about 50 μm and the measurement is performed.

[Surface resistance value]

In an atmosphere of 23°C and 50%RH, using a resistivity meter (manufactured by Mitsubishi Chemical Analyticals, brand name “Loresta GX MCP-T700”), in accordance with JIS K 7194:1994, the four-probe method was used. The resistance value [Ω/□] of the surface of the 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 a measurement sample, for example, a pressure-sensitive adhesive sheet cut into a size of 50 mm width x 50 mm length is used.

[Haze value]

(1) Haze value of adhesive sheet

The adhesive sheet is cut to a size of 50 mm width x 50 mm length to produce a measurement sample. The haze value (H1) of the measurement sample is measured in accordance with JIS K 7136:2000 using “Haze Meter HM150” manufactured by Murakami Shikisai Kijutsu Kenkyu Jojo. Let this be the haze value [%] of the adhesive sheet.

(2) Haze value of adhesive layer

Additionally, only the base film used in the measurement sample was cut to a size of 50 mm ) is calculated. Let this be the haze value [%] of the adhesive layer.

Formula: H3=H1-H2

In the case of an inorganic adhesive sheet containing only an adhesive layer, the haze value (H1) is measured by bonding it to a PET film with a thickness of about 50 ㎛, and as in the case of the above base film, the haze value of the PET film alone ( H2) is measured, and the haze value (H3) of the adhesive layer alone is calculated from the above equation.

Additionally, if the calculated value is less than 0.1 [%], it is expressed as 0 [%].

[Preparation of adhesive composition]

(Preparation example A1)

In a four-necked flask equipped with a stirring blade, thermometer, nitrogen gas introduction tube, and condenser, methoxypolyoxyethylene (average added moles of ethylene oxide: 9) methacrylate/polyoxyethylene (average added moles of ethylene oxide: 9) ) A mixture of methacrylate/hydroxyethyl methacrylate at a molar ratio of 80/5/15 was added. To 100 mol% of this monomer mixture, 0.15 mol% of 2,2'-azobisisobutyronitrile (AIBN) and ethyl acetate were added as polymerization initiators, nitrogen gas was introduced while gently stirring, and polymerization was carried out under predetermined conditions. The reaction was performed to obtain polymer A1 with Mw 38×10 ⁴ and Mn 6.5×10 ⁴ .

(Preparation example A2)

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

(Preparation example A3)

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

(Preparation example A4)

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

(Preparation example A5)

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

[Production of base material]

(Production Example B1)

An aqueous solution (Bytron P, manufactured by H. C. Stark) 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) was prepared. . Additionally, a dispersion containing 25% of polyester resin as a binder (manufactured by Toyobo Corporation, brand name "Vinarol MD-1480" (aqueous dispersion of saturated copolyester resin)) was prepared. The binder was added to a mixed solvent of water and ethanol. 100 parts of the dispersion in solid amount, 50 parts of the above-mentioned conductive polymer aqueous solution in solid amount, and 5 parts of a melamine-based crosslinking agent were added, stirred for about 20 minutes, and thoroughly mixed. In this way, a conductive undercoat layer of about 0.4% NV was added. A composition for forming a conductive undercoat was prepared. This composition for forming a conductive undercoat was applied to one side of a 50 ㎛ thick PET film (elasticity modulus 4.2 GPa) and dried at 120°C for 60 seconds to form a conductive undercoat layer with a thickness of 300 nm. In this way, base film B1 with a conductive undercoat layer was obtained.

(Production Example B2)

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

(Production Example B3)

As a substrate, a 100 μm thick polypropylene/polyethylene/vinyl acetate copolymer multilayer hard extrusion film (elastic modulus 600 MPa) was used instead of the PET film. Otherwise, in the same manner as Production Example B1, base film B3 with a conductive undercoat layer was obtained.

(Production Example B4)

As a substrate, a polypropylene/polyethylene blend film (elastic modulus 600 MPa) with a thickness of 40 μm was used instead of the PET film. Otherwise, in the same manner as Production Example B1, base film B4 with a conductive undercoat layer was obtained.

<Example 1>

85 parts of polymer A1, 2.5 parts of isocyanate-based crosslinking agent (“Coronate HX” manufactured by Tosoh Corporation), and lithium/bis(trifluoromethanesulfonyl)imide (trade name “F-Top EF” manufactured by Mitsubishi Material Denshi Kasei). An ethyl acetate solution of an adhesive containing 15 parts of "-N115") and 0.016 parts of ferric acetylacetone ("Nasem Ferric" manufactured by Nihon Chemical Co., Ltd.) was prepared as the adhesive composition according to this example. This adhesive composition was applied to the surface of the conductive undercoat layer of the base film B1 with a conductive undercoat layer and dried at 130°C for 90 seconds to form an adhesive layer with a thickness of 10 μm. In this way, the single-sided adhesive adhesive sheet according to this example was obtained.

<Examples 2 to 5>

The pressure-sensitive adhesive composition for each example was prepared in the same manner as 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. In the same manner as in Example 1 except that the adhesive composition was used, single-sided adhesive adhesive sheets for each example were obtained.

<Example 6>

The adhesive composition according to Example 2 was prepared, and in the same manner as in Example 2 except that base film B2 with a conductive undercoat layer was used, the adhesive composition was applied and dried on the surface of the conductive undercoat layer of base film B2 with a conductive undercoat layer, A single-sided adhesive adhesive sheet according to the example was obtained.

<Examples 7 to 8>

Prepare the adhesive composition according to Example 1, and use the adhesive composition as a conductive undercoat of the base film with a conductive undercoat layer in the same manner as in Example 1 except that B3 (Example 7) or B4 (Example 8) was used. It was applied to the layer surface and dried to obtain a single-sided adhesive sheet for each example.

<Example 9>

85 parts of polyether polyol A (“PREMINOL S 3011” manufactured by AGC, molecular weight 10000), polyether polyol B (“Sannics GP-3000” manufactured by Sanyo Chemical Industries, Ltd., polyoxypropylene glyceryl ether, number average molecular weight 3000) ) 13 parts, polyether polyol C (“Sannyx GP-1000” manufactured by Sanyo Chemical Industries, 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 (trade name “Ftop EF-N115” manufactured by Mitsubishi Materials Denshi Chemical), 15 parts, and 15 parts ferric acetylacetone (trade name “F-Top EF-N115” manufactured by Nippon Chemical Company) An ethyl acetate solution of an adhesive containing 0.12 parts of ferric ferric iron was prepared as the adhesive composition according to this example. This adhesive composition was applied to the surface of the conductive undercoat layer of the base film B1 with a conductive undercoat layer, and cured at 130°C for 90 seconds to form an adhesive layer with a thickness of 10 μm. In this way, the single-sided adhesive adhesive sheet according to this example was obtained.

<Example 10>

In a four-neck flask equipped with a stirring blade, thermometer, nitrogen gas introduction tube, and condenser, 82 parts of 2-ethylhexyl acrylate, 12 parts of N-vinylpyrrolidone, 3 parts of 4-hydroxyethyl acrylate, and 3 parts of acrylic acid. , 0.05 parts of photoinitiator (“Omnirad651” manufactured by IGM Resins Itaria S. r.l.), 0.1 part of anti-aging agent (“Songnox1010”), cross-linking agent (“NK Ester A-HD-N” manufactured by Shinnakamura Chemical Co., Ltd.) An ultraviolet (UV) curable syrup containing 0.05 parts, 50 parts of conductive filler (“Sil-shield Ag/glass 5/25s” manufactured by ECKA), and 150 parts of conductive filler (“TP25S12” manufactured by Potters) is used in this example. It was prepared as an adhesive composition. This adhesive composition was applied on the release layer of a polyester film with a silicone release layer, the polyester film with a silicone release layer was further bonded, and cured by irradiating UV light at an illumination intensity of 50 mW/cm2 for 5 minutes. In this way, an inorganic double-sided adhesive sheet containing an adhesive layer with a thickness of 30 μm was obtained.

<Example 11>

An inorganic double-sided adhesive sheet according to this example was obtained in the same manner as in Example 10, except that the thickness of the adhesive layer was changed to 50 μm.

Table 1 shows the evaluation results of the schematic composition, adhesive force [N/20 mm], surface resistance value [Ω/□], and haze value [%] of the adhesive sheet for each example.

As shown in Table 1, the pressure-sensitive adhesive sheets according to Examples 1 to 9 have a surface resistance value of the pressure-sensitive adhesive layer of 108 Ω/□ or less, so that a plurality of conductive small pieces (for example, semiconductor pieces) disposed on the pressure-sensitive adhesive are formed through the pressure-sensitive adhesive layer. chips) can be energized simultaneously. In addition, since the adhesive sheets of these examples have an adhesive force to the SUS plate in the range of 0.01 to 4.0 N/20 mm, the conductive small pieces are bonded and reliably fixed, and after the completion of the energization process, the conductive small pieces are well secured from the adhesive layer surface. It can be separated. On the other hand, the adhesive sheets according to Examples 10 and 11 had good conductivity, but the adhesive strength exceeded 4.0 N/20 mm, and it is thought that the separation and removability of the adherend was poor compared to Examples 1 and 9. Additionally, the haze value exceeds 50%, so it is thought that inspection beyond the adhesive sheet cannot be performed or inspection performance is poor.

From the above results, the adhesive sheet with a surface resistance value of the adhesive layer of 108 Ω/□ or less and an adhesive force to the SUS plate within the range of 0.01 to 4.0 N/20 mm can be suitably used for simultaneous inspection of a plurality of conductive small pieces in batches. .

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

1, 2, 101, 201: Adhesive sheet
10, 110, 210: Base layer
20, 120, 220: Adhesive layer
30: Sublayer
150: Conductive small piece

Claims (32)

It is an adhesive sheet provided with an adhesive layer,
The surface resistance value of the adhesive layer is 1.0×10 ⁸ Ω/□ or less,
Adhesion to stainless steel plates is in the range of 0.01 to 4.0 N/20 mm,
The haze value is 50% or less,
An adhesive sheet wherein the adhesive layer contains an ionic compound. delete According to paragraph 1,
An adhesive sheet, wherein the adhesive layer contains an oxyalkylene structural unit. According to paragraph 3,
A pressure-sensitive adhesive sheet, wherein the pressure-sensitive adhesive layer contains a polymer having the oxyalkylene structural unit. According to paragraph 4,
A pressure-sensitive adhesive sheet, wherein the polymer having the oxyalkylene structural unit has the oxyalkylene structural unit in a side chain. According to any one of claims 3 to 5,
A pressure-sensitive adhesive sheet, wherein the content of the oxyalkylene structural unit in the pressure-sensitive adhesive layer is 20 to 95% by weight. delete According to any one of claims 1 and 3 to 5,
An adhesive sheet further comprising a base material layer, wherein the adhesive layer is provided on at least one side of the base layer. According to clause 8,
An adhesive sheet in which the base layer is composed of a resin film with an elastic modulus of 50 MPa or more. According to clause 8,
An adhesive sheet, wherein an undercoat layer is disposed between the base material layer and the adhesive layer. A process of preparing an adhesive sheet on which a plurality of conductive small pieces to be inspected are fixed - where the adhesive sheet has a conductive adhesive layer, and the plurality of conductive small pieces to be inspected are detachably fixed to the surface of the adhesive layer. -class,
A step of energizing at least a portion of the plurality of conductive pieces to be inspected through the adhesive layer and inspecting the conductive pieces to be inspected in the energized state,
A method for producing tested conductive small pieces, wherein the adhesive sheet is the adhesive sheet according to any one of claims 1 and 3 to 5. According to clause 11,
Before the inspection step, the method further includes a step of contacting a surface of the plurality of conductive small pieces to be inspected opposite to the surface fixed to the adhesive layer with a conductive material. delete delete delete delete delete delete delete delete delete delete delete delete delete delete delete delete delete delete delete delete

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