JP2015004048A - Optical adhesive layer, adhesive sheet, optical member and touch panel - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an optical member capable of preventing waviness from occurring, with excellent anticorrosive properties while maintaining high adhesion reliability and transparency, and also to provide an adhesive layer and an adhesive sheet capable of manufacturing such an optical member effectively at a low cost.SOLUTION: An optical adhesive layer includes a base polymer and a rust-preventive agent. The base polymer includes no or substantially no acidic group-containing monomer as a constituent monomer component, and elastic modulus at 85°C is 5.0×10Pa or more.

Description

  The present invention relates to an optical pressure-sensitive adhesive layer, a pressure-sensitive adhesive sheet, an optical member, and a touch panel.

  In recent years, display devices such as a liquid crystal display (LCD) and input devices such as a touch panel have been widely used in various fields. In the manufacture of these display devices and input devices, an adhesive sheet is used for the purpose of bonding optical members. For example, a transparent adhesive sheet is used for bonding optical members in various display devices such as a touch panel.

  In these display devices and input devices, there is a problem that metal wiring corrodes due to moisture, acid gas, saline solution, and corrosive components entering from the outside environment. With the recent increase in size and narrowing of the sensor, there are an increasing number of examples equipped with copper wiring. Copper is excellent in electrical conductivity after silver and is a material useful as a wiring, but is known to be easily oxidized and corroded. In general, for the purpose of preventing metal oxidation / corrosion, a technique of preventing moisture and corrosive components from entering by coating a metal wiring with a moisture-proof protective layer (Patent Document 1) is used.

JP 2011-28594 A

  However, it is necessary to carry out the coating after the metal wiring is applied, and this has been a major problem in terms of reduction in production yield and cost because of the increased number of steps and labor. In addition, when a moisture-proof protective layer is used, adhesion reliability such as adhesiveness and anti-foaming peelability (characteristics such that foaming and peeling do not easily occur at the interface between the pressure-sensitive adhesive sheet and the adherend in a high-temperature environment), Problems sometimes occurred in terms of ensuring transparency.

  In addition, when a metal film is patterned in a laminate having a structure in which a metal film is laminated on a support, a portion where the pattern is applied (pattern forming portion) and a portion where the pattern is not applied (pattern opening) Arise. When such a metal film pattern is applied, the laminated body may be swelled in a high temperature environment due to a difference in linear expansion coefficient between the material constituting the support and the metal constituting the metal film. In addition, when such a wave | undulation arises, it will become easy to generate | occur | produce the problem that it looks bad. This is because a step at the boundary between the pattern forming portion and the pattern opening (hereinafter sometimes referred to as “pattern boundary”) becomes larger than necessary, and the pattern boundary is easily visible.

  Therefore, the object of the present invention is to suppress the occurrence of swell in a high temperature environment, and to have adhesiveness and anti-foaming peelability (characteristics that foam and peeling are unlikely to occur at the interface between an adhesive sheet and an adherend in a high temperature environment). Optical members (especially optical members with an adhesive sheet) excellent in corrosion resistance of metal wiring such as copper wiring while maintaining high adhesion reliability and transparency, etc., and such optical members efficiently and at low cost It is providing the optical adhesive layer and adhesive sheet which can be manufactured by this.

Thus, as a result of intensive studies by the present inventors in order to solve the above-mentioned problems, the use of an appropriate base polymer constituting the pressure-sensitive adhesive layer and the use of a rust preventive agent enable adhesion reliability and transparency. The present invention has been completed by finding that the occurrence of undulation in a high temperature environment can be suppressed by controlling the elastic modulus at high temperature in the pressure-sensitive adhesive composition.
In particular, it has been found that a synergistic effect can be obtained in the corrosion prevention effect by using no rust-containing agent without containing or substantially containing an acidic group-containing monomer as a monomer component constituting the base polymer. The present invention has been completed.

That is, the present invention contains a base polymer and a rust preventive agent, does not contain or substantially does not contain an acidic group-containing monomer as a monomer component constituting the base polymer, and an elastic modulus at 85 ° C. is 5.0. An optical pressure-sensitive adhesive layer characterized by being at least 10 ⁴ Pa is provided.

Furthermore, the present invention contains an acrylic polymer (A) as a main component and a rust inhibitor, and does not contain or substantially contain a carboxyl group-containing monomer as a monomer component that the acrylic polymer (A) constitutes. The optical adhesive layer is characterized by having an elastic modulus at 85 ° C. of 5.0 × 10 ⁴ Pa or more.

  The optical pressure-sensitive adhesive layer preferably contains 5 parts by weight or more of a hydroxyl group-containing monomer with respect to the total amount (100 parts by weight) of monomer components constituting the acrylic polymer (A).

  The optical pressure-sensitive adhesive layer preferably contains 5 parts by weight or more of a nitrogen atom-containing monomer with respect to the total amount (100 parts by weight) of monomer components constituting the acrylic polymer (A).

  The rust inhibitor is preferably a benzotriazole compound.

  The optical pressure-sensitive adhesive layer preferably has a haze (according to JIS K7136) of 1.0% or less.

  The optical pressure-sensitive adhesive layer preferably has a total light transmittance (according to JIS K7361-1) of 90% or more.

  Furthermore, this invention provides the adhesive sheet which has the said optical adhesive layer.

  The pressure-sensitive adhesive sheet preferably has a 180 ° peeling adhesive strength to the glass plate of 8 N / 20 mm or more.

  The pressure-sensitive adhesive sheet preferably has a thickness of 12 to 350 μm.

  Furthermore, the present invention is an optical member having at least the pressure-sensitive adhesive sheet and the substrate, wherein the substrate is provided with metal wiring on at least one side, and the pressure-sensitive adhesive sheet is attached on the surface of the substrate having the metal wiring. An optical member is provided.

  In the optical member, the metal wiring is preferably a copper wiring.

  Furthermore, the present invention is a touch panel having at least the pressure-sensitive adhesive sheet and the substrate, wherein the substrate is provided with metal wiring on at least one side, and the pressure-sensitive adhesive sheet is attached to the surface of the substrate having the metal wiring. Provide a touch panel.

  In the touch panel, the metal wiring is preferably a copper wiring.

According to the optical pressure-sensitive adhesive layer of the present invention, since it can have adhesion reliability, transparency, and corrosion prevention effect, while maintaining high adhesion reliability such as adhesion and anti-foaming peelability, and transparency, The optical member excellent in the corrosion prevention effect of metal wirings, such as copper wiring, and the adhesive layer and adhesive sheet which enable manufacture of such an optical member are obtained. Further, by providing the pressure-sensitive adhesive layer with an anti-corrosion ability, the protective layer is not required to be coated and the number of processes is reduced, so that the cost is reduced and the yield is improved.
In addition, according to the optical pressure-sensitive adhesive layer of the present invention, since the occurrence of undulation in a high-temperature environment can be suppressed, a good-looking optical member and a pressure-sensitive adhesive layer that enables the production of such an optical member And an adhesive sheet is obtained.

FIG. 1 is a schematic view showing a specific example of a preferred embodiment of the optical member of the present invention. FIG. 2 is a schematic diagram showing a specific example of a preferred embodiment of the touch panel of the present invention. FIG. 3 is a top view of the stepped glass used in the evaluation of resistance to foaming and peeling. FIG. 4 is a cross-sectional view (A-A ′ line cross-sectional view) of the stepped glass. FIG. 5 is a cross-sectional view (B-B ′ line cross-sectional view) of the stepped glass. FIG. 6 is a schematic cross-sectional view showing an example of a laminate including a support and a metal film in which undulation has occurred. FIG. 7 is a schematic plan view showing an example of a metal wiring pattern.

[1. Optical adhesive layer]
The optical pressure-sensitive adhesive layer of the present invention contains a base polymer and a rust preventive agent as main components, and does not contain or substantially does not contain an acidic group-containing monomer as a monomer component constituting the base polymer. The elastic modulus at 0 ° C. may be 5.0 × 10 ⁴ Pa or more, and is not particularly limited in other respects. Furthermore, the pressure-sensitive adhesive composition of the present invention contains at least a base polymer and a rust inhibitor.
The optical pressure-sensitive adhesive layer of the present invention does not contain or substantially does not contain an acid group-containing monomer as a monomer component constituting the base polymer, and further contains a rust preventive agent, thereby synergistically preventing corrosion. Effects are obtained, and it has an excellent anti-corrosion effect.

The optical pressure-sensitive adhesive layer of the present invention contains an acrylic polymer (A) as a main component and a rust inhibitor, and the acrylic polymer (A) does not contain a carboxyl group-containing monomer as a constituent monomer component. It may not contain substantially and the elastic modulus of 85 degreeC may be 5.0 * 10 < ⁴ > Pa or more.

  The composition for forming the optical pressure-sensitive adhesive layer of the present invention (pressure-sensitive adhesive composition, precursor composition) may have any form, for example, an emulsion type, a solvent type, a hot melt type (hot Melt type), active energy ray curable type, and the like. In addition, in this specification, an adhesive composition means the composition which forms an adhesive layer, and shall contain the composition which forms an adhesive.

  The base polymer contained in the optical pressure-sensitive adhesive layer of the present invention is not particularly limited. For example, an acrylic polymer, a rubber-based pressure-sensitive adhesive layer (natural rubber-based pressure-sensitive adhesive layer) contained in the acrylic pressure-sensitive adhesive layer as a base polymer. And synthetic rubber-based pressure-sensitive adhesive layers) as a base polymer, silicone-based pressure-sensitive adhesive layers as a base polymer, polyester-based pressure-sensitive polyester layers as a base polymer, urethane -Based adhesive layer contains urethane polymer as base polymer, polyamide-based adhesive layer contains polyamide-based polymer as base polymer, epoxy-based adhesive layer contains epoxy-based polymer as base polymer, vinyl alkyl ether-based adhesive The layer is the base polymer Vinyl alkyl ether polymers containing, such as fluorine-based polymer can be cited fluorine-based pressure-sensitive adhesive layer contains as a base polymer. Among them, the base polymer is preferably an acrylic polymer from the viewpoints of transparency, weather resistance, adhesion reliability, and ease of functional design of the pressure-sensitive adhesive layer since there are many types of monomers. That is, the optical pressure-sensitive adhesive layer of the present invention is preferably an acrylic pressure-sensitive adhesive layer containing an acrylic polymer (A) described later as a base polymer. In addition, a base polymer can be used individually or in combination of 2 or more types.

  Although content of the said base polymer in the optical adhesive layer of this invention is not specifically limited, It is preferable that it is 75 weight% or more (for example, 75-99.9 weight%), More preferably, it is 85 weight% or more ( For example, 85 to 99.9% by weight).

  The optical pressure-sensitive adhesive layer of the present invention contains no or substantially no acidic group-containing monomer (for example, a carboxyl group-containing monomer, a sulfo group-containing monomer, a phosphate group-containing monomer, etc.). For this reason, the corrosion prevention effect of the outstanding metal wiring can be acquired. The content of the acidic group-containing monomer is preferably 0.05% by weight or less (for example, 0 to 0.05% by weight), more preferably 0.01% by weight with respect to the optical pressure-sensitive adhesive layer of the present invention. % Or less (for example, 0 to 0.01% by weight), more preferably 0.001% by weight or less (for example, 0 to 0.001% by weight) can be said to be substantially not contained.

  When the optical pressure-sensitive adhesive layer of the present invention is an acrylic pressure-sensitive adhesive layer, the optical pressure-sensitive adhesive layer of the present invention is an acidic component such as a carboxyl group-containing monomer as a monomer component constituting the acrylic polymer contained as a base polymer. Does not contain or substantially does not contain a group-containing monomer. When the optical pressure-sensitive adhesive layer of the present invention contains an acrylic polymer (A) as a base polymer, it does not contain or substantially does not contain a carboxyl group-containing monomer as a monomer component constituting the acrylic polymer (A). Is more preferable. For this reason, the optical pressure-sensitive adhesive layer of the present invention can obtain an excellent corrosion prevention effect. The meaning of the carboxyl group-containing monomer, the meaning of “substantially not containing”, the monomer having an acidic group other than the carboxyl group, and the like are the same as those in the case of the monomer component constituting the acrylic polymer (A). To do. Further, the content of the carboxyl group-containing monomer is preferably 0.05% by weight or less (for example, 0 to 0.05% by weight), more preferably 0.01% with respect to the total amount of the optical pressure-sensitive adhesive layer of the present invention. What is less than or equal to% by weight (for example, 0 to 0.01% by weight), more preferably less than or equal to 0.001% by weight (for example, 0 to 0.001% by weight) can be said to be substantially not contained.

  The optical pressure-sensitive adhesive layer of the present invention is transparent or has transparency. For this reason, it is excellent in visibility and appearance through the optical pressure-sensitive adhesive layer of the present invention.

  The haze of the optical pressure-sensitive adhesive layer of the present invention (according to JIS K7136) is not particularly limited, but is preferably 1.0% or less, more preferably 0.8% or less. When the haze is 1.0% or less, excellent transparency and excellent appearance can be obtained, which is preferable. The haze is, for example, a pressure-sensitive adhesive layer (thickness: 100 μm), which is allowed to stand in a normal state (23 ° C., 50% RH) for at least 24 hours, and then slide glass (for example, total light transmittance 91.8). % And haze of 0.4%) can be used as a sample and measured using a haze meter (trade name “HM-150” manufactured by Murakami Color Research Laboratory Co., Ltd.).

  The total light transmittance (according to JIS K7361-1) in the visible light wavelength region of the optical pressure-sensitive adhesive layer of the present invention is not particularly limited, but is preferably 85% or more, more preferably 88% or more. When the total light transmittance is 85% or more, excellent transparency and excellent appearance are obtained, which is preferable. The total light transmittance is, for example, a pressure-sensitive adhesive layer (thickness: 100 μm), which is allowed to stand in a normal state (23 ° C., 50% RH) for at least 24 hours. Then, a sample bonded to a slide glass (for example, having a total light transmittance of 91.8% and a haze of 0.4%) was used as a sample, and a haze meter (trade name “HM-” manufactured by Murakami Color Research Laboratory Co., Ltd.) was used. 150 ").

The elastic modulus at 85 ° C. in the optical pressure-sensitive adhesive layer of the present invention is 5.0 × 10 ⁴ Pa or more, more preferably 7.0 × 10 ⁴ Pa or more, and further preferably 9.0 × 10 ⁴ Pa. That's it. Since the optical pressure-sensitive adhesive layer of the present invention has an elastic modulus at 85 ° C. of 5.0 × 10 ⁴ Pa or more, the occurrence of waviness can be suppressed. Therefore, according to the optical pressure-sensitive adhesive layer of the present invention, it is possible to obtain a good-looking optical member or touch panel. This is because it is possible to suppress the occurrence of so-called “pattern appearance” (a phenomenon in which a step at the pattern boundary becomes larger than necessary and the pattern boundary becomes easy to be visually recognized, resulting in poor appearance).

  The measurement of the elastic modulus at 85 ° C. is obtained as follows. After forming the pressure-sensitive adhesive layer (thickness: about 2 mm), this is punched out to φ7.9 mm to produce a columnar pellet to be a measurement sample. The measurement sample is fixed to a jig having a φ7.9 mm parallel plate, and the temperature dependence of the storage elastic modulus G ′ is measured by a dynamic viscoelasticity measuring apparatus (ARES, manufactured by Rheometrics). That is, it refers to the storage elastic modulus (G ′) at 85 ° C. when measured at measurement: shear mode, temperature range: −70 ° C. to 150 ° C., heating rate: 5 ° C./min, frequency: 1 Hz.

  FIG. 6 shows a schematic cross-sectional view of an example of a laminate including a support and a metal film (a laminate having a metal film pattern on the support) in which undulation has occurred in relation to the swell. In FIG. 6, 6 is a laminate, 61 is a support, and 62 is a metal film (metal film pattern). In this way, “swell” means swell and ripple.

  The method for producing the optical pressure-sensitive adhesive layer is not particularly limited. For example, the pressure-sensitive adhesive composition can be produced and, if necessary, produced by irradiation with active energy rays, heat drying, or the like. Specifically, it is prepared by adding a rust inhibitor (for example, the following benzotriazole-based compound, etc.), an additive or the like to a polymerizable monomer mixture or a partial polymer thereof, if necessary, and mixing them. And so on.

  The optical pressure-sensitive adhesive layer of the present invention contains a rust inhibitor. The rust inhibitor includes a compound that prevents rust and corrosion of the metal. Although it does not specifically limit as a rust preventive agent, For example, an amine compound, a benzotriazole type compound, nitrites, etc. are mentioned. In addition, ammonium benzoate, ammonium phthalate, ammonium stearate, ammonium palmitate, ammonium oleate, ammonium carbonate, dicyclohexylamine benzoate, urea, urotropine, thiourea, phenyl carbamate, cyclohexylammonium-N-cyclohexyl And carbamate (CHC). In addition, a rust preventive agent can be used individually or in combination of 2 or more types.

  Examples of the amine compound include 2-amino-2-methyl-1-propanol, monoethanolamine, monoisopropanolamine, diethylethanolamine, hydroxy group-containing amine compounds such as ammonia and aqueous ammonia; cyclic amines such as morpholine; cyclohexyl And cyclic alkylamine compounds such as amines; and linear alkylamines such as 3-methoxypropylamine. Examples of the nitrites include dicyclohexylammonium nitrite (DICHAN), diisopropylammonium nitrite (DIPAN), sodium nitrite, potassium nitrite, and calcium nitrite.

  Above all, the above rust preventive agent is not only benzoic acid from the viewpoint of compatibility with the base polymer and transparency, but also when the base polymer is reacted after addition, it is difficult to inhibit the reaction (crosslinking, polymerization, etc.) of the base polymer. Triazole compounds are preferred.

  Although content of the said rust preventive agent is not specifically limited, It is preferable to contain 0.02-15 weight part with respect to 100 weight part of base polymers. It is preferable that the content is 0.02 part by weight or more because good corrosion prevention performance is easily obtained. On the other hand, when the content is less than 15 parts by weight, it is easy to ensure transparency, and it is easy to ensure adhesion reliability such as anti-foaming peelability, which is preferable.

  In particular, the above base polymer is an acrylic polymer (especially an acrylic polymer (A) described later) from the point that adhesion reliability, transparency and corrosion prevention properties can be obtained in a balanced and high level. The rust inhibitor is preferably a benzotriazole compound. That is, the optical pressure-sensitive adhesive layer of the present invention is an acrylic pressure-sensitive adhesive layer containing at least an acrylic polymer (particularly, acrylic polymer (A) described later) as a base polymer and a benzotriazole-based compound as a rust preventive agent. It is preferable that

[1-1. Benzotriazole compounds]
Although content of a benzotriazole type compound is not specifically limited, It is preferable that it is 0.02-3 weight part with respect to the monomer component whole quantity (100 weight part) which comprises an acrylic polymer (A), More preferably Is 0.02 to 2.5 parts by weight, more preferably 0.02 to 2 parts by weight. That is, the optical pressure-sensitive adhesive layer of the present invention preferably contains 0.02 to 3 parts by weight of a benzotriazole compound with respect to 100 parts by weight of the acrylic polymer (A), and preferably 0.02 to 2.5 parts by weight. More preferably, it is more preferably 0.02 to 2 parts by weight. If the amount of the benzotriazole-based compound is too small, the sheet resistivity change rate T may not be less than a predetermined value. Further, since the amount of the benzotriazole-based compound is not more than a certain value, it is possible to reliably ensure adhesion reliability such as anti-foaming peeling property, and it is also possible to reliably prevent an increase in the haze of the pressure-sensitive adhesive layer or pressure-sensitive adhesive sheet.

（但し、上記式（１）において、Ｒ¹及びＲ²は同一又は異なって、Ｒ¹はベンゼン環上の置換基であって、炭素数１〜６のアルキル基、炭素数１〜６のアルコキシ基、炭素数６〜１４のアリール基、アミノ基、モノ又はジＣ_1-10アルキルアミノ基、アミノ−Ｃ_1-6アルキル基、モノ又はジＣ_1-10アルキルアミノ−Ｃ_1-6アルキル基、メルカプト基、炭素数１〜６のアルコキシカルボニル基等の置換基を示し、ｎは０〜４の整数であって、ｎが２以上である場合は、ｎ個のＲ¹は同一であっても、異なっていても良く、Ｒ²は、水素原子、炭素数１〜１２のアルキル基、炭素数１〜１２のアルコキシ基、炭素数６〜１４のアリール基、アミノ基、モノ又はジＣ_1-10アルキルアミノ基、アミノ−Ｃ_1-6アルキル基、モノ又はジＣ_1-10アルキルアミノ−Ｃ_1-6アルキル基、メルカプト基、炭素数１〜１２のアルコキシカルボニル基等の置換基を示す。） The benzotriazole-based compound is not particularly limited as long as it is a compound having a benzotriazole skeleton, but having a structure represented by the following formula (1) provides a more excellent corrosion prevention effect. preferable.

(In the above formula (1), R ¹ and R ² are the same or different, and R ¹ is a substituent on the benzene ring, which is an alkyl group having 1 to 6 carbon atoms, alkoxy having 1 to 6 carbon atoms. Group, aryl group having 6 to 14 carbon atoms, amino group, mono- or di-C _1-10 alkylamino group, amino-C _1-6 alkyl group, mono- or di-C _1-10 alkylamino-C _1-6 alkyl group , A mercapto group, and a substituent such as an alkoxycarbonyl group having 1 to 6 carbon atoms, n is an integer of 0 to 4, and when n is 2 or more, n R ^{1 s} are the same. May be different, and R ² is a hydrogen atom, an alkyl group having 1 to 12 carbon atoms, an alkoxy group having 1 to 12 carbon atoms, an aryl group having 6 to 14 carbon atoms, an amino group, mono- or di-C _{1. -10} alkylamino group, amino-C _1-6 alkyl group, mono or di C _1-10 alkylamino-C _1-6 A substituent such as an alkyl group, a mercapto group, or an alkoxycarbonyl group having 1 to 12 carbon atoms is shown.)

From the viewpoint of obtaining a more excellent corrosion prevention effect, R ¹ is preferably an alkyl group having 1 to 3 carbon atoms, an alkoxycarbonyl group or the like, and more preferably a methyl group or the like. N is preferably 0 or 1.
From the same viewpoint, R ² is preferably a hydrogen atom, a mono- or di-C _1-10 alkylamino-C _1-6 alkyl group, etc., and a hydrogen atom, a di-C _1-8 alkylamino C _1-4 alkyl group, etc. Is more preferable.

[1-2. Acrylic polymer (A)]
The optical pressure-sensitive adhesive layer of the present invention is preferably an acrylic pressure-sensitive adhesive layer containing the acrylic polymer (A) as a main component. Although specific content of an acrylic polymer (A) is not specifically limited, 75 weight% or more (for example, 75-99.9) with respect to the optical adhesive layer whole quantity (total weight, 100 weight%) of this invention. % By weight), more preferably 85% by weight or more (for example, 85 to 99.9% by weight).

  Although it does not specifically limit as an adhesive composition which forms the optical adhesive layer which contains an acrylic polymer (A) as a main component, For example, the composition which has an acrylic polymer (A) as an essential component; Examples thereof include a composition containing a monomer component constituting the polymer (A) (sometimes referred to as “monomer mixture”) or a partially polymerized product thereof as an essential component. Although not particularly limited, examples of the former include so-called solvent-type compositions, and examples of the latter include so-called active energy ray-curable compositions. In addition, the said adhesive composition may contain the other additive as needed.

  When the “monomer mixture” is composed of a single monomer component, it includes the case where it is composed of two or more monomer components. The “partially polymerized product” means a composition in which one or more components among the components of the monomer mixture are partially polymerized. Especially, the composition which has a monomer mixture or its partial polymer as an essential component for the said adhesive composition is preferable.

  The acrylic polymer (A) is a polymer (polymer) containing an acrylic monomer (acrylic monomer) as an essential monomer unit (monomer unit, monomer constituent unit). In other words, the acrylic polymer (A) is a polymer containing a structural unit derived from an acrylic monomer as a structural unit. That is, the acrylic polymer (A) is a polymer composed (formed) with an acrylic monomer as an essential monomer component. In this specification, “(meth) acryl” represents one or both of “acryl” and “methacryl”, and the same applies to the other. Although the weight average molecular weight of an acrylic polymer (A) is not specifically limited, It is preferable that it is 100,000-5 million.

  The acrylic polymer (A) may be referred to as a (meth) acrylic acid alkyl ester having a linear or branched alkyl group as an essential monomer unit (hereinafter, simply referred to as “(meth) acrylic acid alkyl ester”). ) Is preferable.

  Examples of the (meth) acrylic acid alkyl ester include, for example, methyl (meth) acrylate, ethyl (meth) acrylate, propyl (meth) acrylate, isopropyl (meth) acrylate, butyl (meth) acrylate ((meth) N-butyl acrylate), isobutyl (meth) acrylate, s-butyl (meth) acrylate, t-butyl (meth) acrylate, pentyl (meth) acrylate, isopentyl (meth) acrylate, (meth) Hexyl acrylate, heptyl (meth) acrylate, octyl (meth) acrylate, 2-ethylhexyl (meth) acrylate, isooctyl (meth) acrylate, nonyl (meth) acrylate, isononyl (meth) acrylate, (meth ) Decyl acrylate, Isomethyl (meth) acrylate, Unde (meth) acrylate , Dodecyl (meth) acrylate, tridecyl (meth) acrylate, tetradecyl (meth) acrylate, pentadecyl (meth) acrylate, hexadecyl (meth) acrylate, heptadecyl (meth) acrylate, octadecyl (meth) acrylate And (meth) acrylic acid alkyl esters having 1 to 20 carbon atoms such as isostearyl (meth) acrylate, nonadecyl (meth) acrylate, eicosyl (meth) acrylate, and the like. In addition, you may use (meth) acrylic-acid alkylester individually or in combination of 2 or more types.

  Among these, the (meth) acrylic acid alkyl ester is preferably a (meth) acrylic acid alkyl ester having 1 to 18 carbon atoms in terms of obtaining strong adhesion and adjusting residual stress. Are methyl methacrylate (MMA), butyl acrylate (BA), 2-ethylhexyl acrylate (2EHA), and isostearyl acrylate (ISTA).

  The content (ratio) of the (meth) acrylic acid alkyl ester in the total monomer units of the acrylic polymer (A) (the total amount of monomer components constituting the acrylic polymer (A)) is not particularly limited, but is adhesive reliability. In particular, from the viewpoint of adhesion reliability at low temperatures, 30 to 95 parts by weight is preferable, more preferably 35 to 90 parts by weight, based on the total amount of monomer components (100 parts by weight) constituting the acrylic polymer (A). More preferably, it is 40-85 weight part.

  The acrylic polymer (A) may contain a copolymerizable monomer (copolymerizable monomer) as a monomer unit in addition to the above (meth) acrylic acid alkyl ester. That is, the acrylic polymer (A) may contain a copolymerizable monomer as a constituent monomer component. In addition, the copolymerizable monomer may be used individually or in combination of 2 or more types.

  Preferred examples of the copolymerizable monomer include a hydroxyl group-containing monomer. When the acrylic polymer (A) contains a hydroxyl group-containing monomer as a monomer unit, it is easy to polymerize the constituent monomer component, and it becomes easy to obtain a good cohesive force. For this reason, it becomes easy to obtain strong adhesiveness, and it becomes easy to obtain an excellent antifoaming peeling property by increasing the gel fraction. Furthermore, it becomes easy to suppress whitening of the pressure-sensitive adhesive sheet that may occur in a high-humidity environment.

  The content (ratio) of the hydroxyl group-containing monomer with respect to the total amount (100 parts by weight) of monomer components constituting the acrylic polymer (A) is not particularly limited. When the amount of the hydroxyl group-containing monomer is a certain level or more, whitening of the pressure-sensitive adhesive sheet that may occur in a high humidity environment can be further suppressed, and transparency such as humidified cloudiness resistance can be ensured. The lower limit of the content of the hydroxyl group-containing monomer is preferably 5 parts by weight or more, more preferably 7 parts by weight or more, and still more preferably 10 parts by weight or more. In addition, the upper limit of the content of the hydroxyl group-containing monomer is preferably 40 parts by weight or less from the viewpoint of cohesive strength, ease of obtaining adhesion reliability such as adhesion and resistance to foaming, and 35 parts by weight. More preferably, it is more preferably 30 parts by weight or less.

  Furthermore, as said copolymerizable monomer, a nitrogen atom containing monomer is mentioned preferably. When the acrylic polymer (A) contains a nitrogen atom-containing monomer as a monomer unit, an appropriate cohesive force is easily obtained. For this reason, 180 degree peeling adhesion to glass plates and 180 degree peeling adhesion to acrylic plates are increased to make it easier to obtain strong adhesion, and the gel fraction is increased to provide excellent anti-foaming peeling. It becomes easy to get sex. Furthermore, it becomes easy to obtain moderate flexibility by the pressure-sensitive adhesive layer, and the 300% tensile residual stress is adjusted within a specific range, so that it is easy to obtain excellent stress relaxation property and excellent step following property.

  Although content (ratio) of the said nitrogen atom containing monomer with respect to the monomer component whole quantity (100 weight part) which comprises an acryl-type polymer (A) is not specifically limited, It is preferable that it is 5 weight part or more. The lower limit of the content of the nitrogen atom-containing monomer is 7 parts by weight with respect to the total amount of monomer components (100 parts by weight) constituting the acrylic polymer (A) from the viewpoints of cohesive strength, adhesiveness, and anti-foaming resistance. More preferably, it is more preferably 10 parts by weight or more. Moreover, the upper limit of the content of the nitrogen atom-containing monomer is 40 parts by weight from the point that it becomes easier to obtain appropriate flexibility in the pressure-sensitive adhesive layer, and it becomes easier to obtain excellent stress relaxation properties and excellent step following properties. The amount is preferably less than, more preferably 35 parts by weight or less, and even more preferably 30 parts by weight or less.

  The acrylic polymer (A) can be obtained by polymerizing the monomer unit (monomer component) by a known or conventional polymerization method. Examples of the polymerization method of the acrylic polymer (A) include a solution polymerization method, an emulsion polymerization method, a bulk polymerization method, and a polymerization method by active energy ray irradiation (active energy ray polymerization method). Among them, the solution polymerization method and the active energy ray polymerization method are preferable, and the active energy ray polymerization method is more preferable in terms of transparency of the pressure-sensitive adhesive layer, water resistance, cost, and the like.

  Examples of the active energy rays irradiated in the active energy ray polymerization (photopolymerization) include ionizing radiation such as α rays, β rays, γ rays, neutron rays, electron rays, and ultraviolet rays, and particularly ultraviolet rays. Is preferred. The irradiation energy, irradiation time, irradiation method, and the like of the active energy ray are not particularly limited as long as the photopolymerization initiator can be activated to cause the monomer component to react.

  In the polymerization of the acrylic polymer (A), various common solvents may be used. Examples of such solvents include esters such as ethyl acetate and n-butyl acetate; aromatic hydrocarbons such as toluene and benzene; aliphatic hydrocarbons such as n-hexane and n-heptane; cyclohexane and methyl Examples thereof include alicyclic hydrocarbons such as cyclohexane; organic solvents such as ketones such as methyl ethyl ketone and methyl isobutyl ketone. In addition, a solvent may be used individually or in combination of 2 or more types.

  In the polymerization of the acrylic polymer (A), a polymerization initiator such as a thermal polymerization initiator or a photopolymerization initiator (photoinitiator) may be used depending on the type of polymerization reaction. In addition, a polymerization initiator may be used individually or in combination of 2 or more types.

The photopolymerization initiator is not particularly limited. For example, benzoin ether photopolymerization initiator, acetophenone photopolymerization initiator, α-ketol photopolymerization initiator, aromatic sulfonyl chloride photopolymerization initiator, photo Examples thereof include active oxime photopolymerization initiators, benzoin photopolymerization initiators, benzyl photopolymerization initiators, benzophenone photopolymerization initiators, ketal photopolymerization initiators, and thioxanthone photopolymerization initiators. In addition, a photoinitiator may be used individually or in combination of 2 or more types.

  Examples of the benzoin ether photopolymerization initiator include benzoin methyl ether, benzoin ethyl ether, benzoin propyl ether, benzoin isopropyl ether, benzoin isobutyl ether, 2,2-dimethoxy-1,2-diphenylethane-1-one, Anisole methyl ether etc. are mentioned. Examples of the acetophenone photopolymerization initiator include 2,2-diethoxyacetophenone, 2,2-dimethoxy-2-phenylacetophenone, 1-hydroxycyclohexyl phenyl ketone, 4-phenoxydichloroacetophenone, and 4- (t-butyl). ) Dichloroacetophenone and the like. Examples of the α-ketol photopolymerization initiator include 2-methyl-2-hydroxypropiophenone and 1- [4- (2-hydroxyethyl) phenyl] -2-methylpropan-1-one. It is done. As said aromatic sulfonyl chloride type photoinitiator, 2-naphthalene sulfonyl chloride etc. are mentioned, for example. Examples of the photoactive oxime photopolymerization initiator include 1-phenyl-1,1-propanedione-2- (o-ethoxycarbonyl) -oxime. Examples of the benzoin photopolymerization initiator include benzoin. Examples of the benzyl photopolymerization initiator include benzyl. Examples of the benzophenone photopolymerization initiator include benzophenone, benzoylbenzoic acid, 3,3′-dimethyl-4-methoxybenzophenone, polyvinylbenzophenone, α-hydroxycyclohexyl phenyl ketone, and the like. Examples of the ketal photopolymerization initiator include benzyl dimethyl ketal. Examples of the thioxanthone photopolymerization initiator include thioxanthone, 2-chlorothioxanthone, 2-methylthioxanthone, 2,4-dimethylthioxanthone, isopropylthioxanthone, 2,4-diisopropylthioxanthone, dodecylthioxanthone, and the like.

  Although the usage-amount of the said photoinitiator is not specifically limited, For example, with respect to 100 weight part of all the monomer units (A total of the monomer component which comprises an acrylic polymer (A)) of acrylic polymer (A), it is 0. The amount is preferably 001 to 1 part by weight, more preferably 0.01 to 0.50 part by weight.

  Further, the thermal polymerization initiator is not particularly limited. For example, an azo polymerization initiator, a peroxide polymerization initiator (eg, dibenzoyl peroxide, tert-butyl permaleate, etc.), a redox polymerization start Agents and the like. Of these, the azo polymerization initiators disclosed in JP-A No. 2002-69411 are preferable. Examples of the azo polymerization initiator include 2,2′-azobisisobutyronitrile (hereinafter sometimes referred to as “AIBN”), 2,2′-azobis-2-methylbutyronitrile (hereinafter referred to as “AIBN”). AMBN ”), 2,2′-azobis (2-methylpropionic acid) dimethyl, 4,4′-azobis-4-cyanovaleric acid, and the like.

  The amount of the thermal polymerization initiator used is not particularly limited. For example, in the case of the azo polymerization initiator, all monomer units of the acrylic polymer (A) (total amount of monomer components constituting the acrylic polymer (A)). 0.05-0.5 weight part is preferable with respect to 100 weight part, More preferably, it is 0.1-0.3 weight part.

[1-3. Carboxyl group-containing monomers]
The optical pressure-sensitive adhesive layer of the present invention contains no or substantially no acidic group-containing monomer as a monomer component constituting the base polymer. When the optical pressure-sensitive adhesive layer of the present invention is an acrylic pressure-sensitive adhesive layer, the optical pressure-sensitive adhesive layer of the present invention substantially contains a carboxyl group-containing monomer as a monomer component constituting the acrylic polymer (A). Preferably not. In addition, "substantially not containing" means not actively blending unless it is inevitably mixed. The carboxyl group-containing monomer means a monomer having at least one carboxyl group in the molecule. Specifically, from the viewpoint that a more excellent corrosion prevention effect can be obtained, the content of the carboxyl group-containing monomer is 0. 0% relative to the total amount of monomer components (100 parts by weight) constituting the acrylic polymer (A). 05 parts by weight or less (for example, 0 to 0.05 parts by weight) is preferable, more preferably 0.01 parts by weight or less (for example, 0 to 0.01 parts by weight), and still more preferably 0.001 parts by weight or less (for example, , 0 to 0.001 parts by weight) can be said to be substantially not contained. Examples of the carboxyl group-containing monomer include (meth) acrylic acid, itaconic acid, maleic acid, fumaric acid, crotonic acid, and isocrotonic acid. The carboxyl group-containing monomer includes, for example, anhydrous Acid anhydride group-containing monomers such as maleic acid and itaconic anhydride are also included.

  Furthermore, when the optical pressure-sensitive adhesive layer of the present invention is an acrylic pressure-sensitive adhesive layer, the optical pressure-sensitive adhesive layer of the present invention comprises an acrylic polymer (A) from the viewpoint of obtaining a better corrosion prevention effect. As a constituent monomer component, not only substantially does not contain a carboxyl group-containing monomer, but also a monomer having an acidic group (sulfo group, phosphoric acid group, etc.) other than the carboxyl group constitutes the acrylic polymer (A). It is preferable that the monomer component is not substantially contained. That is, it is preferable that the acrylic polymer (A) preferably contains substantially neither a carboxyl group-containing monomer nor any other monomer having an acidic group as a constituent monomer component. Specifically, the total amount of the carboxyl group-containing monomer as the monomer component constituting the acrylic polymer (A) and the other monomer having an acidic group is the total amount of monomer components constituting the acrylic polymer (A) (100 parts by weight). ) Is preferably 0.05 parts by weight or less (for example, 0 to 0.05 parts by weight), more preferably 0.01 parts by weight or less (for example, 0 to 0.01 parts by weight), and still more preferably 0. What is 0.001 part by weight or less (for example, 0 to 0.001 part by weight) can be said to be substantially not contained.

  In addition, the optical pressure-sensitive adhesive layer of the present invention contains an acidic group as a monomer component constituting a polymer other than the acrylic polymer (A) (for example, an acrylic polymer (B) described later) from the same viewpoint. It is preferable that the monomer is not contained or substantially not contained. For example, it is preferable that a carboxyl group-containing monomer is not substantially contained. In addition, about the meaning of "not containing substantially", a preferable grade, and the monomer etc. which have acidic groups other than a carboxyl group, it shall be the same as that of the case where it is a monomer component which comprises an acrylic polymer (A). .

[1-4. Basic group-containing monomer]
In addition, it is preferable that the optical adhesive layer of this invention does not contain a basic group containing monomer as a monomer component which comprises a base polymer, or does not contain substantially. For example, when the optical pressure-sensitive adhesive layer of the present invention is an acrylic pressure-sensitive adhesive layer containing an acrylic polymer (A) as a base polymer, the monomer component constituting the polymer other than the acrylic polymer (A) is basic. It is preferable that the group-containing monomer is not substantially contained, and even if it is not a monomer component constituting various polymers, it is preferable that the basic layer-containing monomer is not substantially contained in the pressure-sensitive adhesive layer. The same as in the case of the carboxyl group-containing monomer. The same applies to the meaning of “substantially not contained”, the preferred degree, and the like.

[1-5. Hydroxyl-containing monomer]
The hydroxyl group-containing monomer means a monomer having at least one hydroxyl group in the molecule. A monomer having at least one hydroxyl group in the molecule and having at least one carboxyl group in the molecule is a carboxyl group-containing monomer and not a hydroxyl group-containing monomer. Although it does not specifically limit as said hydroxyl-containing monomer, Specifically, (meth) acrylic-acid 2-hydroxyethyl, (meth) acrylic-acid 2-hydroxypropyl, (meth) acrylic-acid 2-hydroxybutyl, ( 3-hydroxypropyl (meth) acrylate, 4-hydroxybutyl (meth) acrylate, 6-hydroxyhexyl (meth) acrylate, hydroxyoctyl (meth) acrylate, hydroxydecyl (meth) acrylate, (meth) acrylic acid Hydroxyl-containing (meth) acrylic acid esters such as hydroxy lauryl and (meth) acrylic acid (4-hydroxymethylcyclohexyl); vinyl alcohol, allyl alcohol and the like. Among these, the hydroxyl group-containing monomer is preferably a hydroxyl group-containing (meth) acrylic acid ester, more preferably 2-hydroxyethyl acrylate (HEA), (meta) from the viewpoint of improving the compatibility of the benzotriazole-based compound. ) 2-hydroxypropyl acrylate (HPA), 4-hydroxybutyl acrylate (4HBA). In addition, the hydroxyl-containing monomer may be used individually or in combination of 2 or more types.

[1-6. Nitrogen atom-containing monomer]
The nitrogen atom-containing monomer means a monomer having at least one nitrogen atom in the molecule (in one molecule). However, the hydroxyl group-containing monomer does not include the nitrogen atom-containing monomer. That is, in this specification, the monomer having a hydroxyl group and a nitrogen atom in the molecule is included in the nitrogen atom-containing monomer. The monomer having at least one nitrogen atom in the molecule and having at least one carboxyl group in the molecule is a carboxyl group-containing monomer and not a nitrogen atom-containing monomer.

  As said nitrogen atom containing monomer, N-vinyl cyclic amide, (meth) acrylamides, etc. are preferable from a viewpoint of improving foaming peeling resistance. In addition, the nitrogen atom containing monomer may be used individually or in combination of 2 or more types.

（式（２）中、Ｒ³は２価の有機基を示す） As said N-vinyl cyclic amide, the N-vinyl cyclic amide represented by following formula (2) is preferable from a viewpoint that the compatibility of a benzotriazole type compound improves.

(In formula (2), R ³ represents a divalent organic group)

R ³ in the above formula (2) is a divalent organic group, preferably a divalent saturated hydrocarbon group or an unsaturated hydrocarbon group, more preferably a divalent saturated hydrocarbon group (for example, carbon number). 3-5 alkylene groups, etc.).

  The N-vinyl cyclic amide represented by the above formula (2) includes N-vinyl-2-pyrrolidone (NVP) and N-vinyl from the viewpoint of further improving the anti-foaming peeling property and the compatibility of the benzotriazole-based compound. -2-piperidone, N-vinyl-2-caprolactam, N, N-dimethyl (meth) acrylamide, N, N-diethyl (meth) acrylamide, N-vinyl-3-morpholinone, N-vinyl-1,3-oxazine 2-one, N-vinyl-3,5-morpholinedione, and the like are preferable, and N-vinyl-2-pyrrolidone, N-vinyl-2-caprolactam, N, N-dimethyl (meth) acrylamide, N, N-diethyl (meth) acrylamide, more preferably N-vinyl-2-pyrrolidone.

  Examples of the (meth) acrylamides include (meth) acrylamide, N-alkyl (meth) acrylamide, N, N-dialkyl (meth) acrylamide and the like. Examples of the N-alkyl (meth) acrylamide include N-ethyl (meth) acrylamide, N-isopropyl (meth) acrylamide, Nn-butyl (meth) acrylamide, N-octylacrylamide and the like. Furthermore, the N-alkyl (meth) acrylamide includes (meth) acrylamide having an amino group such as dimethylaminoethyl (meth) acrylamide, diethylaminoethyl (meth) acrylamide, and dimethylaminopropyl (meth) acrylamide. Examples of the N, N-dialkyl (meth) acrylamide include N, N-dimethyl (meth) acrylamide, N, N-diethyl (meth) acrylamide, N, N-dipropyl (meth) acrylamide, and N, N-diisopropyl. (Meth) acrylamide, N, N-di (n-butyl) (meth) acrylamide, N, N-di (t-butyl) (meth) acrylamide and the like can be mentioned.

  The (meth) acrylamides include, for example, various N-hydroxyalkyl (meth) acrylamides. Examples of the N-hydroxyalkyl (meth) acrylamide include N-methylol (meth) acrylamide, N- (2-hydroxyethyl) (meth) acrylamide, N- (2-hydroxypropyl) (meth) acrylamide, N- (1-hydroxypropyl) (meth) acrylamide, N- (3-hydroxypropyl) (meth) acrylamide, N- (2-hydroxybutyl) (meth) acrylamide, N- (3-hydroxybutyl) (meth) acrylamide, N- (4-hydroxybutyl) (meth) acrylamide, N-methyl-N-2-hydroxyethyl (meth) acrylamide, etc. are mentioned.

  The (meth) acrylamides include, for example, various N-alkoxyalkyl (meth) acrylamides. Examples of the N-alkoxyalkyl (meth) acrylamide include N-methoxymethyl (meth) acrylamide and N-butoxymethyl (meth) acrylamide.

  Examples of the nitrogen atom-containing monomer other than the N-vinyl cyclic amide and the (meth) acrylamides include aminoethyl (meth) acrylate, dimethylaminoethyl (meth) acrylate, and dimethylamino (meth) acrylate. Amino group-containing monomers such as propyl and (meth) acrylic acid t-butylaminoethyl; cyano group-containing monomers such as acrylonitrile and methacrylonitrile; (meth) acryloylmorpholine, N-vinylpiperazine, N-vinylpyrrole, N-vinyl Imidazole, N-vinylpyrazine, N-vinylmorpholine, N-vinylpyrazole, vinylpyridine, vinylpyrimidine, vinyloxazole, vinylisoxazole, vinylthiazole, vinylisothiazole, vinylpyridazine, (meth) acryloylpi Heterocycle-containing monomers such as lidone, (meth) acryloylpyrrolidine, (meth) acryloylpiperidine, N-methylvinylpyrrolidone; maleimide monomers such as N-cyclohexylmaleimide, N-isopropylmaleimide, N-laurylmaleimide, N-phenylmaleimide Itaconimide monomers such as N-methylitaconimide, N-ethylitaconimide, N-butylitaconimide, N-octylitaconimide, N-2-ethylhexitaconimide, N-laurylitaconimide, N-cyclohexylitaconimide, N- (meth) acryloyloxymethylenesuccinimide, N- (meth) acryloyl-6-oxyhexamethylenesuccinimide, N- (meth) acryloyl-8-oxyoctamethylenesuccin Imide group-containing monomers succinimide monomers such as bromide; 2- (meth) acrylate isocyanate group-containing monomers such acryloyloxyethyl isocyanate.

[1-7. Other copolymerizable monomers]
As the copolymerizable monomer in the acrylic polymer (A), in addition to the nitrogen atom-containing monomer and the hydroxyl group-containing monomer, for example, (meth) acrylic acid alkoxyalkyl ester [for example, (meth) acrylic acid 2-methoxyethyl , (Meth) acrylic acid 2-ethoxyethyl, (meth) acrylic acid methoxytriethylene glycol, (meth) acrylic acid 3-methoxypropyl, (meth) acrylic acid 3-ethoxypropyl, (meth) acrylic acid 4-methoxybutyl , (Meth) acrylic acid 4-ethoxybutyl, etc.]; epoxy group-containing monomers [for example, glycidyl (meth) acrylate, methyl glycidyl (meth) acrylate, etc.]; sulfonic acid group-containing monomers [for example, sodium vinyl sulfonate, etc. ]; Phosphate group-containing monomer; alicyclic hydrocarbon group (Meth) acrylic acid ester [for example, (meth) acrylic acid cyclopentyl, (meth) acrylic acid cyclohexyl, (meth) acrylic acid isobornyl etc.]; (meth) acrylic acid ester having an aromatic hydrocarbon group [for example, ( Phenyl) (meth) acrylate, phenoxyethyl (meth) acrylate, benzyl (meth) acrylate, etc.]; vinyl esters [eg, vinyl acetate, vinyl propionate, etc.]; aromatic vinyl compounds [eg, styrene, vinyltoluene, etc. Olefins or dienes [for example, ethylene, propylene, butadiene, isoprene, isobutylene and the like]; vinyl ethers [for example, vinyl alkyl ether and the like]; vinyl chloride and the like.

  Furthermore, a polyfunctional monomer is also mentioned as a copolymerizable monomer in the said acrylic polymer (A). The polyfunctional monomer acts as a crosslinking component. Examples of the polyfunctional monomer include hexanediol di (meth) acrylate, butanediol di (meth) acrylate, (poly) ethylene glycol di (meth) acrylate, (poly) propylene glycol di (meth) acrylate, and neopentyl. Glycol di (meth) acrylate, pentaerythritol di (meth) acrylate, pentaerythritol tri (meth) acrylate, dipentaerythritol hexa (meth) acrylate, trimethylolpropane tri (meth) acrylate, tetramethylolmethane tri (meth) acrylate, Examples include allyl (meth) acrylate, vinyl (meth) acrylate, divinylbenzene, epoxy acrylate, polyester acrylate, and urethane acrylate. In addition, the polyfunctional monomer may be used individually or in combination of 2 or more types.

  Although content (ratio) of the said polyfunctional monomer in all the monomer units of an acrylic polymer (A) is not specifically limited, With respect to the monomer component whole quantity (100 weight part) which comprises an acrylic polymer (A), 0.5 parts by weight or less (for example, 0 to 0.5 parts by weight) is preferable, more preferably 0 to 0.35 parts by weight, and still more preferably 0 to 0.2 parts by weight. It is preferable that the content of the polyfunctional monomer is 0.5 parts by weight or less because the pressure-sensitive adhesive layer has an appropriate cohesive force and the adhesive force and step absorbability are easily improved. In addition, when using a crosslinking agent, it is not necessary to use a polyfunctional monomer, but when the crosslinking agent is not used, the content of the polyfunctional monomer is preferably 0.001 to 0.5 parts by weight. More preferably, it is 0.001-0.35 weight part, More preferably, it is 0.002-0.2 weight part.

[1-8. Acrylic polymer (B)]
When the optical pressure-sensitive adhesive layer of the present invention contains an acrylic polymer (A) as a base polymer, the optical pressure-sensitive adhesive layer of the present invention has a weight average molecular weight of 1000 to 30000 together with the acrylic polymer (A). It is preferable to contain a certain acrylic polymer (B). When the acrylic polymer (B) is contained, the adhesiveness to the adherend at the interface of the pressure-sensitive adhesive sheet is improved, so that it is easy to obtain strong adhesiveness and excellent foam peeling resistance. In the present specification, the “acrylic polymer (B) having a weight average molecular weight of 1,000 to 30,000” may be simply referred to as “acrylic polymer (B)”.

  Preferred examples of the acrylic polymer (B) include acrylic polymers composed of (meth) acrylic acid ester having a cyclic structure in the molecule as an essential monomer component, and having a cyclic structure in the molecule (meth). More preferred are acrylic polymers composed of acrylic acid esters and (meth) acrylic acid alkyl esters having a linear or branched alkyl group as essential monomer components. That is, the acrylic polymer (B) preferably includes an acrylic polymer containing a (meth) acrylic acid ester having a cyclic structure in the molecule as a monomer unit, and has a cyclic structure in the molecule as a monomer unit (meta An acrylic polymer containing an acrylic acid ester and a (meth) acrylic acid alkyl ester having a linear or branched alkyl group is more preferred.

  The cyclic structure (ring) of the (meth) acrylic acid ester (hereinafter sometimes referred to as “ring-containing (meth) acrylic acid ester”) having a cyclic structure in the molecule (one molecule) is an aromatic ring. Any of non-aromatic rings may be used and is not particularly limited. Examples of the aromatic ring include aromatic carbocycles [for example, monocyclic carbocycles such as benzene rings, condensed carbocycles such as naphthalene rings], and various aromatic heterocycles. Examples of the non-aromatic ring include non-aromatic aliphatic rings (non-aromatic alicyclic rings) [for example, cycloalkane rings such as cyclopentane ring, cyclohexane ring, cycloheptane ring, cyclooctane ring, etc. A cycloalkene ring such as a cyclohexene ring], a non-aromatic bridged ring [for example, a bicyclic hydrocarbon ring in pinane, pinene, bornane, norbornane, norbornene, etc .; a tricyclic or more aliphatic hydrocarbon in adamantane, etc. Ring (bridged hydrocarbon ring) and the like], non-aromatic heterocyclic ring [for example, epoxy ring, oxolane ring, oxetane ring and the like] and the like.

Examples of the tricyclic or higher aliphatic hydrocarbon ring (tricyclic or higher bridged hydrocarbon ring) include, for example, a dicyclopentanyl group represented by the following formula (3a) and the following formula (3b). Dicyclopentenyl group, adamantyl group represented by the following formula (3c), tricyclopentanyl group represented by the following formula (3d), tricyclopentenyl group represented by the following formula (3e), and the like. .

  That is, as the ring-containing (meth) acrylic acid ester, for example, (meth) acrylic acid cyclopentyl, (meth) acrylic acid cyclohexyl, (meth) acrylic acid cycloheptyl, (meth) acrylic acid cyclooctyl etc. Acrylic acid cycloalkyl ester; (meth) acrylic acid ester having a bicyclic aliphatic hydrocarbon ring such as isobornyl (meth) acrylate; dicyclopentanyl (meth) acrylate, dicyclopentanyloxyethyl (meth) Tricyclic or higher aliphatic such as acrylate, tricyclopentanyl (meth) acrylate, 1-adamantyl (meth) acrylate, 2-methyl-2-adamantyl (meth) acrylate, 2-ethyl-2-adamantyl (meth) acrylate (Meth) acrylic acid having a hydrocarbon ring Tel; (meth) acrylic acid aryl esters such as phenyl (meth) acrylate, (meth) acrylic acid aryloxyalkyl esters such as phenoxyethyl (meth) acrylate, and (meth) acrylic acids such as benzyl (meth) acrylate Examples include (meth) acrylic acid esters having an aromatic ring such as arylalkyl esters. Especially, as said ring containing (meth) acrylic acid ester, non-aromatic ring containing (meth) acrylic acid ester is preferable, More preferably, cyclohexyl acrylate (CHA), cyclohexyl methacrylate (CHMA), acrylic Dicyclopentanyl acid (DCPA) and dicyclopentanyl methacrylate (DCPMA) are preferred, and dicyclopentanyl acrylate (DCPA) and dicyclopentanyl methacrylate (DCPMA) are more preferred. In addition, ring containing (meth) acrylic acid ester may be used individually or in combination of 2 or more types.

  Among the non-aromatic ring-containing (meth) acrylic acid esters, (meth) acrylic acid esters having three or more aliphatic hydrocarbon rings (particularly three or more bridged hydrocarbon rings) are used. In particular, it is preferable in that it hardly causes polymerization inhibition. In addition, a dicyclopentanyl group represented by the above formula (3a) having no unsaturated bond, an adamantyl group represented by the above formula (3c), and a tricyclopentanyl group represented by the above formula (3d) When the (meth) acrylic acid ester is used, it is possible to further improve the anti-foaming peelability, and to remarkably improve the adhesion to a low-polar adherend such as polyethylene or polypropylene. .

  The content (ratio) of the ring-containing (meth) acrylic acid ester in all monomer units of the acrylic polymer (B) (total amount of monomer components constituting the acrylic polymer (B)) is not particularly limited, but the acrylic polymer 10-90 weight part is preferable with respect to the monomer component whole quantity (100 weight part) which comprises (B), More preferably, it is 20-80 weight part. When the content of the ring-containing (meth) acrylic acid ester is 10 parts by weight or more, the anti-foaming peelability is easily improved, which is preferable. Moreover, it is preferable for the content to be 90 parts by weight or less because the pressure-sensitive adhesive layer has appropriate flexibility, and the adhesive strength, step absorbability and the like are easily improved.

  Examples of the (meth) acrylic acid alkyl ester having a linear or branched alkyl group as a monomer unit of the acrylic polymer (B) include, for example, methyl (meth) acrylate and ethyl (meth) acrylate. , Propyl (meth) acrylate, isopropyl (meth) acrylate, butyl (meth) acrylate, isobutyl (meth) acrylate, s-butyl (meth) acrylate, t-butyl (meth) acrylate, (meth) Pentyl acrylate, isopentyl (meth) acrylate, hexyl (meth) acrylate, heptyl (meth) acrylate, octyl (meth) acrylate, 2-ethylhexyl (meth) acrylate, isooctyl (meth) acrylate, (meth ) Nonyl acrylate, isononyl (meth) acrylate, decyl (meth) acrylate Isodecyl (meth) acrylate, undecyl (meth) acrylate, dodecyl (meth) acrylate, tridecyl (meth) acrylate, tetradecyl (meth) acrylate, pentadecyl (meth) acrylate, hexadecyl (meth) acrylate, ( Examples include (meth) acrylic acid alkyl esters having 1 to 20 carbon atoms in the alkyl group, such as heptadecyl (meth) acrylate, octadecyl (meth) acrylate, nonadecyl (meth) acrylate, and eicosyl (meth) acrylate. Of these, methyl methacrylate (MMA) is preferable in terms of good compatibility with the acrylic polymer (A). In addition, said (meth) acrylic-acid alkylester may be used individually or in combination of 2 or more types.

  Content (ratio) of (meth) acrylic acid alkyl ester having the above linear or branched alkyl group in all monomer units of acrylic polymer (B) (total amount of monomer components constituting acrylic polymer (B)) Is not particularly limited, but is preferably 10 to 90 parts by weight, more preferably 20 to 80 parts by weight with respect to the total amount (100 parts by weight) of the monomer components constituting the acrylic polymer (B) in terms of resistance to foaming and peeling. Part by weight, more preferably 20 to 60 parts by weight. When the content is 10 parts by weight or more, the adhesive force to an adherend made of an acrylic resin or polycarbonate is easily improved, which is preferable.

  As the monomer unit of the acrylic polymer (B), in addition to the ring-containing (meth) acrylic acid ester and the (meth) acrylic acid alkyl ester having a linear or branched alkyl group, these monomers can be used together. A monomer capable of polymerization (copolymerizable monomer) may be contained. The content (ratio) of the copolymerizable monomer in all monomer units of the acrylic polymer (B) (total amount of monomer components constituting the acrylic polymer (B)) is not particularly limited, but the acrylic polymer (B ) Is preferably 49.9 parts by weight or less (for example, 0 to 49.9 parts by weight), more preferably 30 parts by weight or less, based on the total amount of monomer components (100 parts by weight). Moreover, a copolymerizable monomer may be used individually or in combination of 2 or more types.

  Examples of the copolymerizable monomer (the copolymerizable monomer constituting the acrylic polymer (B)) as the monomer unit of the acrylic polymer (B) include (meth) acrylic acid alkoxyalkyl esters [for example, (meta ) 2-methoxyethyl acrylate, 2-ethoxyethyl (meth) acrylate, methoxytriethylene glycol (meth) acrylate, 3-methoxypropyl (meth) acrylate, 3-ethoxypropyl (meth) acrylate, (meth ) 4-methoxybutyl acrylate, 4-ethoxybutyl (meth) acrylate, etc .; hydroxyl group (hydroxyl group) -containing monomers [for example, 2-hydroxyethyl (meth) acrylate, 2-hydroxypropyl (meth) acrylate, (Meth) acrylic acid 2-hydroxybutyl, (meth) acrylic 3-hydroxypropyl, 4-hydroxybutyl (meth) acrylate, hydroxyalkyl (meth) acrylate such as 6-hydroxyhexyl (meth) acrylate, vinyl alcohol, allyl alcohol, etc.]; amide group-containing monomers [for example, ( Meth) acrylamide, N, N-dimethyl (meth) acrylamide, N-methylol (meth) acrylamide, N-methoxymethyl (meth) acrylamide, N-butoxymethyl (meth) acrylamide, N-hydroxyethyl (meth) acrylamide, etc.] Amino group-containing monomers [for example, aminoethyl (meth) acrylate, dimethylaminoethyl (meth) acrylate, t-butylaminoethyl (meth) acrylate, etc.]; cyano group-containing monomers [for example, acrylonitrile, methacrylonitrile ]; Sulfonic acid group-containing monomer [for example, sodium vinyl sulfonate]; phosphoric acid group-containing monomer [for example, 2-hydroxyethylacryloyl phosphate]; isocyanate group-containing monomer [for example, 2-methacryloyloxyethyl isocyanate, etc.] And imide group-containing monomers [cyclohexylmaleimide, isopropylmaleimide and the like].

  As described above, the acrylic polymer (B) includes a (meth) acrylic acid ester having a cyclic structure in the molecule as a monomer unit and a (meth) acrylic acid alkyl ester having a linear or branched alkyl group. An acrylic polymer is preferred. Especially, it is preferable that it is an acrylic polymer containing the ring-containing (meth) acrylic acid ester and the (meth) acrylic acid alkyl ester which has said linear or branched alkyl group as a monomer unit. In the acrylic polymer containing a ring-containing (meth) acrylic acid ester and a (meth) acrylic acid alkyl ester having a linear or branched alkyl group as the monomer unit, a monomer component constituting the acrylic polymer (B) The amount of the ring-containing (meth) acrylic acid ester relative to the total amount (100 parts by weight) is not particularly limited, but is preferably 10 to 90 parts by weight, and more preferably 20 to 80 parts by weight. In addition, the content of the (meth) acrylic acid alkyl ester having a linear or branched alkyl group is not particularly limited, but is preferably 10 to 90 parts by weight, more preferably 20 to 80 parts by weight, and still more preferably. 20 to 60 parts by weight.

  Further, a particularly preferred specific constitution of the acrylic polymer (B) is selected from the group consisting of (1) dicyclopentanyl acrylate, dicyclopentanyl methacrylate, cyclohexyl acrylate, and cyclohexyl methacrylate as monomer units. And at least one monomer and (2) an acrylic polymer containing methyl methacrylate. (1) Dicyclopentanyl acrylate, dicyclopentanyl methacrylate, cyclohexyl acrylate, in all monomer units of acrylic polymer (B) in acrylic polymer (B) having a particularly preferred specific configuration as described above, And the content of cyclohexyl methacrylate (when two or more are included, the total amount thereof) is 30 to 70 parts by weight with respect to the total amount of monomer components (100 parts by weight) constituting the acrylic polymer (B), ( 2) The content of methyl methacrylate is preferably 30 to 70 parts by weight. However, the acrylic polymer (B) is not limited to the specific configuration.

  The acrylic polymer (B) can be obtained by polymerizing the monomer component by a known or conventional polymerization method. Examples of the polymerization method of the acrylic polymer (B) include a solution polymerization method, an emulsion polymerization method, a bulk polymerization method, a polymerization method by active energy ray irradiation (active energy ray polymerization method), and the like. Among these, a bulk polymerization method and a solution polymerization method are preferable, and a solution polymerization method is more preferable.

  In the polymerization of the acrylic polymer (B), various common solvents may be used. Examples of the solvent include esters such as ethyl acetate and n-butyl acetate; aromatic hydrocarbons such as toluene and benzene; aliphatic hydrocarbons such as n-hexane and n-heptane; cyclohexane and methylcyclohexane Organic solvents such as ketones such as methyl ethyl ketone and methyl isobutyl ketone. In addition, such a solvent may be used individually or in combination of 2 or more types.

  Furthermore, in the polymerization of the acrylic polymer (B), a known or conventional polymerization initiator (for example, a thermal polymerization initiator or a photopolymerization initiator) may be used. In addition, a polymerization initiator may be used individually or in combination of 2 or more types.

  Examples of the thermal polymerization initiator include 2,2′-azobisisobutyronitrile (AIBN), 2,2′-azobis-2-methylbutyronitrile (AMBN), 2,2′-azobis (2- Methyl propionate) dimethyl, 4,4'-azobis-4-cyanovaleric acid, 2,2'-azobis (4-methoxy-2,4-dimethylvaleronitrile), 2,2'-azobis (2,4- Azo initiators such as dimethylvaleronitrile), 1,1′-azobis (cyclohexane-1-carbonitrile), 2,2′-azobis (2,4,4-trimethylpentane); benzoyl peroxide, t-butyl Hydroperoxide, di-t-butyl peroxide, t-butylperoxybenzoate, dicumyl peroxide, 1,1-bis (t-butylperoxy)- And peroxide initiators such as 3,3,5-trimethylcyclohexane and 1,1-bis (t-butylperoxy) cyclododecane. In addition, when performing solution polymerization, it is preferable to use an oil-soluble polymerization initiator. Moreover, a thermal-polymerization initiator may be used individually or in combination of 2 or more types.

  Although it does not specifically limit as the usage-amount of the said thermal polymerization initiator, For example, it is 0 with respect to 100 weight part of all the monomer units (The monomer component total amount which comprises an acrylic polymer (B)) of an acrylic polymer (B). 0.1 to 15 parts by weight.

  The photopolymerization initiator is not particularly limited, and examples thereof include the same photopolymerization initiator as that used in the polymerization of the acrylic polymer (A) mentioned above. The usage-amount of the said photoinitiator is not specifically limited, It selects suitably.

  In the polymerization of the acrylic polymer (B), a chain transfer agent may be used to adjust the molecular weight (specifically, to adjust the weight average molecular weight to 1000 to 30000). Examples of the chain transfer agent include 2-mercaptoethanol, α-thioglycerol, 2,3-dimercapto-1-propanol, octyl mercaptan, t-nonyl mercaptan, dodecyl mercaptan (lauryl mercaptan), t-dodecyl mercaptan, glycidyl. Mercaptan, thioglycolic acid, methyl thioglycolate, ethyl thioglycolate, propyl thioglycolate, butyl thioglycolate, t-butyl thioglycolate, 2-ethylhexyl thioglycolate, octyl thioglycolate, isooctyl thioglycolate, Of decyl thioglycolate, dodecyl thioglycolate, thioglycolate of ethylene glycol, thioglycolate of neopentyl glycol, pentaerythritol Oh glycolic acid esters, alpha-methyl styrene dimer and the like. Of these, α-thioglycerol and methyl thioglycolate are preferable, and α-thioglycerol is particularly preferable from the viewpoint of suppressing whitening of the pressure-sensitive adhesive sheet due to humidification. In addition, a chain transfer agent may be used individually or in combination of 2 or more types.

  The content (use amount) of the chain transfer agent is not particularly limited, but is 0 with respect to 100 parts by weight of the total monomer units of the acrylic polymer (B) (the total amount of monomer components constituting the acrylic polymer (B)). 0.1 to 20 parts by weight is preferred, more preferably 0.2 to 15 parts by weight, and still more preferably 0.3 to 10 parts by weight. By setting the content (amount of use) of the chain transfer agent in the above range, an acrylic polymer having a weight average molecular weight controlled to 1000 to 30000 can be easily obtained.

  The weight average molecular weight (Mw) of the acrylic polymer (B) is 1000 to 30000, preferably 1000 to 20000, more preferably 1500 to 10000, and still more preferably 2000 to 8000. Since the weight average molecular weight of the acrylic polymer (B) is 1000 or more, the adhesive strength and retention characteristics are improved, and the foaming peel resistance is improved. On the other hand, since the weight average molecular weight of the acrylic polymer (B) is 30000 or less, it is easy to increase the adhesive force and the foaming peel resistance is improved.

The weight average molecular weight (Mw) of the acrylic polymer (B) can be determined in terms of polystyrene by the GPC method. For example, it can be measured under the following conditions using a high-speed GPC device “HPLC-8120GPC” manufactured by Tosoh Corporation.
Column: TSKgel SuperHZM-H / HZ4000 / HZ3000 / HZ2000
Solvent: Tetrahydrofuran Flow rate: 0.6 ml / min

  Although the glass transition temperature (Tg) of the said acrylic polymer (B) is not specifically limited, 20-300 degreeC is preferable, More preferably, it is 30-300 degreeC, More preferably, it is 40-300 degreeC. It is preferable for the glass transition temperature of the acrylic polymer (B) to be 20 ° C. or higher, since the anti-foaming resistance is easily improved. Further, when the glass transition temperature of the acrylic polymer (B) is 300 ° C. or lower, the pressure-sensitive adhesive layer has appropriate flexibility, and it is easy to obtain good adhesive strength and good step absorbability, and excellent adhesion. It is preferable because reliability is easily obtained.

The glass transition temperature (Tg) of the acrylic polymer (B) is a glass transition temperature (theoretical value) represented by the following formula.
1 / Tg = W ₁ / Tg ₁ + W ₂ / Tg ₂ +... + W _n / Tg _n
In the above formula, Tg is the glass transition temperature of the acrylic polymer (B) (unit: K), Tg _i is the glass transition temperature at which monomer i has formed a homopolymer (unit: K), W _i is the monomer i Represents the weight fraction in the total amount of monomer components (i = 1, 2,... N).
As Tg of the homopolymer of the monomer constituting the acrylic polymer (B), the values shown in Table 1 below can be adopted. In addition, as the Tg of a homopolymer of a monomer not listed in Table 1, the values described in “Polymer Handbook” (3rd edition, John Wiley & Sons, Inc., 1989) can be adopted. Furthermore, as a Tg of a homopolymer of a monomer not described in the above document, a value obtained by the above-described measurement method (tan δ peak top temperature by viscoelasticity test) can be adopted.

なお、表１における「ＤＣＰＭＡ／ＭＭＡ＝６０／４０」のコポリマーは、ＤＣＰＭＡ６０重量部とＭＭＡ４０重量部のコポリマーを意味する。

The copolymer of “DCPMA / MMA = 60/40” in Table 1 means a copolymer of 60 parts by weight of DCPMA and 40 parts by weight of MMA.

  The content of the acrylic polymer (B) when the optical pressure-sensitive adhesive layer of the present invention contains the acrylic polymer (A) and (B) is not particularly limited, but 100 parts by weight of the acrylic polymer (A) Is preferably 1 to 30 parts by weight, more preferably 2 to 20 parts by weight, and still more preferably 2 to 10 parts by weight. That is, the content of the acrylic polymer (B) in the optical pressure-sensitive adhesive layer of the present invention is not particularly limited, but is 1 to 30 parts by weight with respect to 100 parts by weight of the total monomer units of the acrylic polymer (A). Is preferable, more preferably 2 to 20 parts by weight, still more preferably 2 to 10 parts by weight. Although content of the acrylic polymer (B) in an adhesive composition is not specifically limited, For example, 1-30 weight part is preferable with respect to 100 weight part of said monomer mixtures, More preferably, it is 2-20 weight part. Yes, more preferably 2 to 10 parts by weight. It is preferable that the content of the acrylic polymer (B) is 1 part by weight or more because excellent adhesiveness and excellent anti-foaming resistance can be easily obtained. Further, when the content of the acrylic polymer (B) is 30 parts by weight or less, excellent transparency and adhesion reliability are easily obtained, which is preferable.

  It does not specifically limit as a preparation method of the said adhesive layer containing acrylic polymer (A) and (B). For example, a benzotriazole compound, an acrylic polymer (B), an additive or the like is added to the monomer mixture forming the acrylic polymer (A) or a partial polymer thereof as necessary, and then mixed. Produced.

[1-9. Additive]
In the optical pressure-sensitive adhesive layer of the present invention, a crosslinking agent, a crosslinking accelerator, a silane coupling agent, a tackifying resin (rosin derivative, polyterpene resin, petroleum resin, oil-soluble phenol, etc.), an anti-aging agent, if necessary. Known additives such as fillers, colorants (pigments, dyes, etc.), ultraviolet absorbers, antioxidants, chain transfer agents, plasticizers, softeners, surfactants, antistatic agents, etc. It may be included in a range that does not impair. In addition, such an additive may be used individually or in combination of 2 or more types.

  When the pressure-sensitive adhesive layer contains a cross-linking agent, the base polymer is cross-linked to increase the gel fraction and to improve the anti-foaming resistance. For example, since acrylic polymer (particularly acrylic polymer (A)) can be cross-linked and the gel fraction can be easily controlled, it is easy to improve anti-foaming resistance. Examples of the crosslinking agent include an isocyanate crosslinking agent, an epoxy crosslinking agent, a melamine crosslinking agent, a peroxide crosslinking agent, a urea crosslinking agent, a metal alkoxide crosslinking agent, a metal chelate crosslinking agent, and a metal. Examples thereof include salt-based crosslinking agents, carbodiimide-based crosslinking agents, oxazoline-based crosslinking agents, aziridine-based crosslinking agents, and amine-based crosslinking agents. In particular, when the optical pressure-sensitive adhesive layer of the present invention is a pressure-sensitive adhesive layer containing an acrylic polymer (A) as a base polymer, an isocyanate-based crosslinking agent or an epoxy-based crosslinking agent is used in terms of improving foaming resistance. Preferably, it is an isocyanate type crosslinking agent. In addition, a crosslinking agent may be used individually or in combination of 2 or more types.

  Examples of the isocyanate-based crosslinking agent (polyfunctional isocyanate compound) include lower aliphatic polyisocyanates such as 1,2-ethylene diisocyanate, 1,4-butylene diisocyanate, and 1,6-hexamethylene diisocyanate; cyclopentylene diisocyanate , Cyclohexylene diisocyanate, isophorone diisocyanate, hydrogenated tolylene diisocyanate, hydrogenated xylene diisocyanate, and the like; 2,4-tolylene diisocyanate, 2,6-tolylene diisocyanate, 4,4'-diphenylmethane diisocyanate And aromatic polyisocyanates such as xylylene diisocyanate. Examples of the isocyanate-based crosslinking agent include trimethylolpropane / tolylene diisocyanate adduct [trade name “Coronate L” manufactured by Nippon Polyurethane Industry Co., Ltd.], trimethylolpropane / hexamethylene diisocyanate adduct [Nippon Polyurethane. Commercial products such as Kogyo Co., Ltd., trade name “Coronate HL”, trimethylolpropane / xylylene diisocyanate adduct [Mitsui Chemicals, trade name “Takenate D-110N”] are also included.

  Examples of the epoxy crosslinking agent (polyfunctional epoxy compound) include N, N, N ′, N′-tetraglycidyl-m-xylenediamine, diglycidylaniline, and 1,3-bis (N, N-diglycidyl). Aminomethyl) cyclohexane, 1,6-hexanediol diglycidyl ether, neopentyl glycol diglycidyl ether, ethylene glycol diglycidyl ether, propylene glycol diglycidyl ether, polyethylene glycol diglycidyl ether, polypropylene glycol diglycidyl ether, sorbitol polyglycidyl ether Glycerol polyglycidyl ether, pentaerythritol polyglycidyl ether, polyglycerol polyglycidyl ether, sorbitan polyglycidyl ether, trime Roll propane polyglycidyl ether, adipic acid diglycidyl ester, o-phthalic acid diglycidyl ester, triglycidyl-tris (2-hydroxyethyl) isocyanurate, resorcin diglycidyl ether, bisphenol-S-diglycidyl ether, intramolecular Examples thereof include an epoxy resin having two or more epoxy groups. Moreover, as said epoxy type crosslinking agent, commercial items, such as Mitsubishi Gas Chemical Co., Ltd. make and brand name "Tetrad C", are mentioned, for example.

  The content of the crosslinking agent in the optical pressure-sensitive adhesive layer is not particularly limited. For example, when the optical pressure-sensitive adhesive layer of the present invention is a pressure-sensitive adhesive layer containing an acrylic polymer (A) as a base polymer, 0.001-10 weight part is preferable with respect to 100 weight part of acrylic polymers (A), More preferably, it is 0.01-5 weight part. When the content of the cross-linking agent is 0.001 part by weight or more, the anti-foaming peelability is easily improved, which is preferable. On the other hand, it is preferable that the content of the crosslinking agent is 10 parts by weight or less because the pressure-sensitive adhesive layer has appropriate flexibility and the adhesive force is easily improved.

  It is preferable that a silane coupling agent is contained in the optical pressure-sensitive adhesive layer because excellent adhesion to glass (particularly excellent adhesion reliability to glass at high temperature and high humidity) can be easily obtained. The silane coupling agent is not particularly limited, but γ-glycidoxypropyltrimethoxysilane, γ-glycidoxypropyltriethoxysilane, γ-aminopropyltrimethoxysilane, N-phenyl-aminopropyltrimethoxysilane. Etc. Of these, γ-glycidoxypropyltrimethoxysilane is preferred. Furthermore, as said silane coupling agent, commercial items, such as a brand name "KBM-403" (Shin-Etsu Chemical Co., Ltd. product), are mentioned, for example. In addition, a silane coupling agent may be used individually or in combination of 2 or more types.

  The content of the silane coupling agent in the optical pressure-sensitive adhesive layer is not particularly limited. For example, the optical pressure-sensitive adhesive layer of the present invention is a pressure-sensitive adhesive layer containing an acrylic polymer (A) as a base polymer. In this case, 0.01 to 1 part by weight is preferable and more preferably 0.03 to 0.5 part by weight with respect to 100 parts by weight of the acrylic polymer (A) from the viewpoint of improving adhesion reliability to glass.

[2. Adhesive sheet]
The adhesive sheet of this invention should just have the said optical adhesive layer (optical adhesive layer of this invention), and is not specifically limited by another point.

  The pressure-sensitive adhesive sheet of the present invention may be a double-sided pressure-sensitive adhesive sheet whose both surfaces are the pressure-sensitive adhesive layer surface, or may be a single-sided pressure-sensitive adhesive sheet whose only one surface is the pressure-sensitive adhesive layer surface. Especially, it is preferable that it is a double-sided adhesive sheet from a viewpoint of bonding two members together. In the present specification, the term “adhesive sheet” includes a tape-shaped material, that is, an “adhesive tape”. In the present specification, the pressure-sensitive adhesive layer surface may be referred to as “adhesive surface”.

  The pressure-sensitive adhesive sheet of the present invention may be provided with a separator (release liner) on the pressure-sensitive adhesive surface until use.

  The pressure-sensitive adhesive sheet of the present invention may be a so-called “base-less type” pressure-sensitive adhesive sheet (hereinafter sometimes referred to as “base-material-less pressure-sensitive adhesive sheet”) that does not have a base material (base material layer). Further, it may be a pressure-sensitive adhesive sheet having a base material (hereinafter sometimes referred to as “pressure-sensitive adhesive sheet with a base material”). Examples of the base material-less pressure-sensitive adhesive sheet include a double-sided pressure-sensitive adhesive sheet composed only of the pressure-sensitive adhesive layer, and a pressure-sensitive adhesive layer other than the pressure-sensitive adhesive layer and the pressure-sensitive adhesive layer (referred to as “other pressure-sensitive adhesive layer”). ) And the like. On the other hand, examples of the pressure-sensitive adhesive sheet with a substrate include a pressure-sensitive adhesive sheet having the pressure-sensitive adhesive layer on at least one side of the substrate. Especially, a base material-less adhesive sheet (base material-less double-sided adhesive sheet) is preferable, More preferably, it is a base material-less double-sided adhesive sheet which consists only of the said adhesive layer. The “base material (base material layer)” does not include a separator that is peeled off when the adhesive sheet is used (attached).

  The pressure-sensitive adhesive sheet of the present invention is preferably a substrate-less pressure-sensitive adhesive sheet. Since it can be said that a corrosion-preventing function can be imparted to some extent if it is a pressure-sensitive adhesive sheet with a substrate using a moisture-proof substrate, the substrate-less pressure-sensitive adhesive sheet has a higher significance for imparting a corrosion-preventing function.

[2-1. Various physical properties of adhesive sheet]

  180 ° peel adhesion to the glass plate of the pressure-sensitive adhesive sheet of the present invention (particularly, 180 ° peel adhesion to the glass plate of the pressure-sensitive adhesive surface provided by the pressure-sensitive adhesive layer (optical pressure-sensitive adhesive layer of the present invention)) Although not particularly limited, it is preferably 8 N / 20 mm or more, more preferably 10 N / 20 mm or more, from the viewpoint that if the adhesive force is high, sufficient adhesion to the metal surface is obtained and the corrosion prevention effect is improved. More preferably, it is 12N / 20mm or more, More preferably, it is 14N / 20mm or more. If the adhesive sheet of the present invention has a 180 ° peel-off adhesive strength with respect to the glass plate of a certain value or more, the adhesiveness to glass and the deterrence of floating at the step are further improved. In addition, although the upper limit of 180 degree peeling adhesive force with respect to the glass plate of the adhesive sheet of this invention is not specifically limited, For example, 40 N / 20mm is preferable, More preferably, it is 60 N / 20mm. The 180 ° peel adhesion to the glass plate is determined by the following 180 ° peel adhesion measurement method.

  Although it does not specifically limit as said glass plate, For example, brand name "Soda lime glass # 0050" (made by Matsunami Glass Industrial Co., Ltd.) is mentioned. Moreover, an alkali free glass, a chemically strengthened glass, etc. are mentioned.

  180 ° peel adhesion to the acrylic plate of the pressure-sensitive adhesive sheet of the present invention (particularly, 180 ° peel adhesion to the acrylic plate of the pressure-sensitive adhesive surface provided by the pressure-sensitive adhesive layer (optical pressure-sensitive adhesive layer of the present invention)) Although not particularly limited, it is preferably 10 N / 20 mm or more, more preferably 12 N / 20 mm or more from the viewpoint that if the adhesive force is high, sufficient adhesion to the metal surface is obtained and the corrosion prevention effect is improved. More preferably, it is 14 N / 20 mm or more. The pressure-sensitive adhesive sheet of the present invention preferably has a 180 ° peel-off adhesive strength to the acrylic plate of 10 N / 20 mm or more because good adhesiveness to the acrylic plate and good anti-floating property at a step are easily obtained. In addition, although the upper limit of 180 degree peeling adhesive force with respect to the acrylic board of the adhesive sheet of this invention is not specifically limited, For example, it is 40 N / 20mm, More preferably, it is 60 N / 20mm. The 180 ° peel adhesive strength with respect to the acrylic plate is determined by the following 180 ° peel adhesive measuring method.

  Although it does not specifically limit as said acrylic board, For example, a PMMA board (Brand name "Acrylite", Mitsubishi Rayon Co., Ltd. product) etc. are mentioned.

(A-1. Measuring method of 180 ° peeling adhesion)
The pressure-sensitive adhesive sheet is bonded to the adherend and bonded under the conditions of a 2 kg roller and one reciprocal pressure bonding, and aged for 30 minutes in an atmosphere of 23 ° C. and 50% RH. After aging, in accordance with JIS Z 0237, the pressure-sensitive adhesive sheet is peeled off from the adherend under the conditions of 23 ° C., 50% RH, tensile speed 300 mm / min, peeling angle 180 °, and peeled off 180 °. The force (N / 20 mm) is measured.

(B. Thickness)
Although the thickness (total thickness) of the adhesive sheet of this invention is not specifically limited, 12-350 micrometers is preferable, More preferably, it is 12-300 micrometers. It is preferable that the thickness is not less than a certain value because peeling at the stepped portion hardly occurs. Further, it is preferable that the thickness is not more than a certain value because it is easy to maintain an excellent appearance during production. The thickness of the pressure-sensitive adhesive sheet of the present invention does not include the thickness of the separator.

(C. Hayes)
The haze (according to JIS K7136) of the pressure-sensitive adhesive sheet of the present invention is not particularly limited, but is preferably 1.0% or less, more preferably 0.8% or less. When the haze is 1.0% or less, excellent transparency and excellent appearance can be obtained, which is preferable. The haze is obtained by, for example, leaving the pressure-sensitive adhesive sheet in a normal state (23 ° C., 50% RH) for at least 24 hours and then peeling the separator sheet if it has a separator, for example, a slide glass (for example, total light transmittance 91 8% and 0.4% haze) as a sample and can be measured using a haze meter (Murakami Color Research Laboratory, trade name “HM-150”).

(D. Total light transmittance)
The total light transmittance (according to JIS K7361-1) in the visible light wavelength region of the pressure-sensitive adhesive sheet of the present invention is not particularly limited, but is preferably 85% or more, more preferably 88% or more. When the total light transmittance is 85% or more, excellent transparency and excellent appearance are obtained, which is preferable. The total light transmittance can be determined by, for example, leaving the pressure-sensitive adhesive sheet in a normal state (23 ° C., 50% RH) for at least 24 hours, and then peeling the sheet if it has a separator. Measured using a haze meter (trade name “HM-150”, manufactured by Murakami Color Research Laboratory Co., Ltd.) Can do.

[2-2. Manufacturing method of adhesive sheet]
Although the adhesive sheet of this invention is not specifically limited, It is preferable to manufacture in accordance with a well-known thru | or usual manufacturing method. For example, when the pressure-sensitive adhesive sheet of the present invention is a substrate-less pressure-sensitive adhesive sheet, it can be obtained by forming the pressure-sensitive adhesive layer (optical pressure-sensitive adhesive layer of the present invention) on the separator by the above method. When the pressure-sensitive adhesive sheet of the present invention is a pressure-sensitive adhesive sheet with a base material, it may be obtained by directly forming the pressure-sensitive adhesive layer on the surface of the base material (direct copying method) or once on the separator. After forming the adhesive layer, it may be obtained by providing the adhesive layer on the substrate by transferring (bonding) it to the substrate (transfer method).

[2-3. Adhesive layer of adhesive sheet]
The gel fraction (ratio of solvent-insoluble components) of the pressure-sensitive adhesive layer (optical pressure-sensitive adhesive layer of the present invention) of the pressure-sensitive adhesive sheet of the present invention is not particularly limited, but is preferably 65 to 99%, more preferably 68 to. 95%, more preferably 70 to 95%. When the gel fraction is 65% or more, the cohesive force of the pressure-sensitive adhesive layer is improved, foaming and peeling at the interface with the adherend in a high-temperature environment are suppressed, and excellent anti-foaming resistance is obtained. It becomes easy and preferable. In addition, it is preferable that the gel fraction is 99% or less because appropriate flexibility can be obtained and the adhesiveness can be further improved.

(Gel fraction)
Specifically, the gel fraction (ratio of solvent-insoluble components) is a value calculated by, for example, the following “method for measuring gel fraction”.

About 0.1 g of the pressure-sensitive adhesive layer was collected from the pressure-sensitive adhesive sheet, wrapped in a porous tetrafluoroethylene sheet (trade name “NTF1122”, manufactured by Nitto Denko Corporation) with an average pore diameter of 0.2 μm, and then bound with a string. The weight at that time is measured, and the weight is defined as the weight before immersion. The weight before immersion is the total weight of the pressure-sensitive adhesive layer (the pressure-sensitive adhesive layer collected above), the tetrafluoroethylene sheet, and the kite string. In addition, the total weight of the tetrafluoroethylene sheet and the kite string is also measured, and this weight is defined as the wrapping weight.
Next, a pressure-sensitive adhesive layer wrapped with a tetrafluoroethylene sheet and bound with a kite string (referred to as “sample”) is placed in a 50 ml container filled with ethyl acetate and allowed to stand at 23 ° C. for 7 days. Then, the sample (after ethyl acetate treatment) is taken out from the container, transferred to an aluminum cup, dried in a dryer at 130 ° C. for 2 hours to remove ethyl acetate, the weight is measured, and the weight is immersed. After weight.
Then, the gel fraction is calculated from the following formula.
Gel fraction [% (% by weight)] = (XY) / (ZY) × 100

  The gel fraction can be controlled by, for example, the monomer composition of the base polymer (for example, the acrylic polymer (A)), the weight average molecular weight, the use amount (addition amount) of the crosslinking agent, and the like.

(300% tensile residual stress)
The 300% tensile residual stress of the pressure-sensitive adhesive layer (optical pressure-sensitive adhesive layer of the present invention) is not particularly limited, is preferably 7~25N / cm ^2, more preferably 7~20N / cm ^2, further Preferably it is 7-16 N / cm < ² >, More preferably, it is 7-14 N / cm < ² >. It is preferable that the 300% tensile residual stress is 7 N / cm ² or more because good foam peeling resistance can be easily obtained. Moreover, it is preferable that the 300% tensile residual stress is 25 N / cm ² or less because good stress relaxation properties can be obtained, and good step followability can be easily obtained.

  When the pressure-sensitive adhesive sheet of the present invention has the above-mentioned pressure-sensitive adhesive layer having a 300% tensile residual stress within a specific range, it becomes easy to obtain excellent stress relaxation properties, and easily exhibits excellent step-following properties. . For example, it can satisfactorily follow large steps (for example, steps having a height of about 45 μm, particularly steps having a height of 20 to 50 μm).

The above-mentioned 300% tensile residual stress is that the pressure-sensitive adhesive layer is stretched in the length direction to an elongation (strain) of 300% in an environment of 23 ° C., the elongation is maintained, and the pressure-sensitive adhesive layer is 300 seconds after the end of the tension. This is a value (N / cm ² ) obtained by obtaining the tensile load applied to the above and dividing the tensile load by the initial cross-sectional area (cross-sectional area before pulling) of the pressure-sensitive adhesive layer. The initial elongation of the pressure-sensitive adhesive layer is 100%.

(Thickness)
Although the thickness of the said adhesive layer (especially optical adhesive layer of this invention) is not specifically limited, 12-350 micrometers is preferable, More preferably, it is 12-300 micrometers. When the thickness is equal to or larger than a certain level, the step following property and adhesion reliability are improved, which is preferable. Moreover, it is especially excellent in handleability and manufacturability that the thickness is below a certain value, which is preferable.

(Production method)
Although it does not specifically limit as a manufacturing method of the said adhesive layer (optical adhesive layer of this invention), For example, the said adhesive composition is apply | coated (coating) on a base material or a release liner, and as needed. And drying, curing, or drying and curing.

  In addition, a well-known coating method may be used for application | coating (coating) of the said adhesive composition. For example, a coater such as a gravure roll coater, a reverse roll coater, a kiss roll coater, a dip roll coater, a bar coater, a knife coater, a spray coater, a comma coater, or a direct coater may be used.

[2-4. Other layers of adhesive sheet]
The pressure-sensitive adhesive sheet of the present invention may have other layers in addition to the pressure-sensitive adhesive layer (optical pressure-sensitive adhesive layer of the present invention). Examples of other layers include other pressure-sensitive adhesive layers (pressure-sensitive adhesive layers other than the pressure-sensitive adhesive layer), intermediate layers, undercoat layers, and the like. In addition, the adhesive sheet of this invention may have two or more other layers.

[2-5. Adhesive sheet substrate]
Although it does not specifically limit as a base material in case the adhesive sheet of this invention is an adhesive sheet with a base material, For example, various optical films, such as a plastic film, an antireflection (AR) film, a polarizing plate, a phase difference plate, are mentioned. It is done. Examples of materials such as the plastic film include polyester resins such as polyethylene terephthalate (PET), acrylic resins such as polymethyl methacrylate (PMMA), polycarbonate, triacetyl cellulose (TAC), polysulfone, polyarylate, polyimide, Polyvinyl chloride, polyvinyl acetate, polyethylene, polypropylene, ethylene-propylene copolymer, trade name “ARTON (cyclic olefin polymer, manufactured by JSR Corporation)”, trade name “ZEONOR (cyclic olefin polymer, Nippon Zeon Co., Ltd.) A plastic material such as a cyclic olefin polymer. In addition, these plastic materials may be used individually or in combination of 2 or more types. In addition, the above-mentioned “base material” is a part that is attached to the adherend together with the adhesive layer when the adhesive sheet is attached to the adherend. A separator (release liner) that is peeled off when the adhesive sheet is used (attached) is not included in the “base material”.

  The substrate is preferably transparent. The total light transmittance (according to JIS K7361-1) in the visible light wavelength region of the substrate is not particularly limited, but is preferably 85% or more, and more preferably 88% or more. Further, the haze of the substrate (according to JIS K7136) is not particularly limited, but is preferably 1.0% or less, more preferably 0.8% or less. Examples of such a transparent substrate include PET films and non-oriented films such as trade name “Arton” and trade name “Zeonor”.

  Although the thickness of the said base material is not specifically limited, For example, 12-500 micrometers is preferable. In addition, the said base material may have any form of a single layer and a multilayer. The surface of the base material may be appropriately subjected to known and conventional surface treatments such as physical treatment such as corona discharge treatment and plasma treatment, and chemical treatment such as undercoating treatment.

[2-6. Adhesive sheet separator]
The pressure-sensitive adhesive sheet of the present invention may be provided with a separator (release liner) on the pressure-sensitive adhesive surface until use. When the pressure-sensitive adhesive sheet of the present invention is a double-sided pressure-sensitive adhesive sheet, each pressure-sensitive adhesive surface may be protected by two separators, respectively, or in a roll shape by one separator whose both surfaces are release surfaces. You may protect in the form wound. The separator is used as a protective material for the pressure-sensitive adhesive layer, and is peeled off when being applied to an adherend. Moreover, when the adhesive sheet of this invention is a base material-less adhesive sheet, a separator also plays the role as a support body of an adhesive layer. Note that the separator is not necessarily provided.

  A conventional release paper or the like can be used as the separator, and is not particularly limited. For example, the base material which has a peeling process layer, the low adhesive base material which consists of a fluoropolymer, the low adhesive base material which consists of a nonpolar polymer, etc. are mentioned. As a base material which has the said peeling process layer, the plastic film, paper, etc. which were surface-treated with peeling processing agents, such as a silicone type, a long-chain alkyl type, a fluorine type, and molybdenum sulfide, are mentioned, for example. Examples of the fluorine-based polymer in the low adhesion substrate made of the above-mentioned fluoropolymer include polytetrafluoroethylene, polychlorotrifluoroethylene, polyvinyl fluoride, polyvinylidene fluoride, tetrafluoroethylene-hexafluoropropylene copolymer, chloro Examples include fluoroethylene-vinylidene fluoride copolymer. Examples of the nonpolar polymer include olefin-based resins (eg, polyethylene, polypropylene, etc.), and polyester-based substrates (polyethylene terephthalate-based substrates, polyethylene naphthalate-based substrates, polybutylene terephthalate-based groups). Material etc.) is also used. The separator can be formed by a known or common method. Further, the thickness of the separator is not particularly limited.

[2-7. Application of adhesive sheet]
Since the pressure-sensitive adhesive sheet of the present invention has the pressure-sensitive adhesive layer (optical pressure-sensitive adhesive layer of the present invention), it is excellent in adhesiveness and anti-foaming resistance. Furthermore, it is excellent in stress relaxation property and excellent in step following ability. For this reason, it is excellent in adhesive reliability, especially in high temperature. Moreover, it is excellent in the swell prevention property in a high temperature environment.

  For this reason, the pressure-sensitive adhesive sheet of the present invention is usefully used for adherends that are liable to foam at the interface at high temperatures. For example, polymethyl methacrylate resin (PMMA) may contain unreacted monomers, and foaming due to foreign matters is likely to occur at high temperatures. Polycarbonate (PC) tends to generate outgas of water and carbon dioxide at high temperatures. Since the pressure-sensitive adhesive sheet of the present invention is excellent in anti-foaming peelability, it is also useful for a plastic adherend containing such a resin.

The pressure-sensitive adhesive sheet of the present invention is also useful for adherends having a large linear expansion coefficient in addition to adherends having a small linear expansion coefficient. The adherend having a small linear expansion coefficient is not particularly limited. For example, a glass plate (linear expansion coefficient: 0.3 × 10 ^{−5 to} 0.8 × 10 ⁻⁵ / ° C.), polyethylene terephthalate group Examples thereof include materials (PET film, linear expansion coefficient: 1.5 × 10 ⁻⁵ to 2 × 10 ⁻⁵ / ° C.). In addition, the adherend having a large linear expansion coefficient is not particularly limited, and examples thereof include a resin base material having a large linear expansion coefficient, and more specifically, a polycarbonate resin base material (PC, linear expansion coefficient: 7 × 10 ⁻⁵ to 8 × 10 ⁻⁵ / ° C.), polymethyl methacrylate resin substrate (PMMA, linear expansion coefficient: 7 × 10 ⁻⁵ to 8 × 10 ⁻⁵ / ° C.), cycloolefin polymer substrate ( COP, linear expansion coefficient: 6 × 10 ^{−5 to} 7 × 10 ⁻⁵ / ° C.), trade name “ZEONOR” (manufactured by ZEON CORPORATION), trade name “ARTON” (manufactured by JSR Corporation), and the like.

  The pressure-sensitive adhesive sheet of the present invention is useful for bonding an adherend having a small linear expansion coefficient and an adherend having a large linear expansion coefficient. Specifically, the pressure-sensitive adhesive sheet of the present invention is preferably used for bonding a glass adherend (for example, a glass plate, chemically tempered glass, a glass lens, etc.) and the resin substrate having a large linear expansion coefficient.

  Thus, the pressure-sensitive adhesive sheet of the present invention is useful for laminating adherends of various materials, and is particularly useful for laminating a glass adherend and a plastic adherend. The plastic adherend may be an optical film such as a plastic film having an ITO (indium and tin oxide) layer on the surface.

  Furthermore, the pressure-sensitive adhesive sheet of the present invention is useful for an adherend having a step on the surface in addition to an adherend having a smooth surface. In particular, the pressure-sensitive adhesive sheet of the present invention has a glass-adhered body and the above-described linear expansion coefficient even when at least one of the glass-adhered body and the resin base material having a large linear expansion coefficient has a step on the surface. It is useful for bonding with large resin substrates.

  For example, the pressure-sensitive adhesive sheet of the present invention is a laminate composed of a PET film (polyethylene terephthalate support), an ITO layer and a copper wiring, and the ITO layer is patterned. Can be suitably used when a laminated body having a structure in which is connected to an adherend. The laminate is composed of materials having different elastic moduli and linear expansion, and undulation may occur in a high temperature environment, but the pressure-sensitive adhesive sheet of the present invention effectively suppresses the occurrence of undulation in a high temperature environment. Because it can.

  The pressure-sensitive adhesive sheet of the present invention is preferably used for manufacturing applications of portable electronic devices. This is because the pressure-sensitive adhesive sheet of the present invention can suppress the occurrence of swell in a high-temperature environment, so that a portable electronic device with a good display portion can be easily manufactured. Examples of the portable electronic device include mobile phones, PHS, smart phones, tablets (tablet computers), mobile computers (mobile PCs), personal digital assistants (PDAs), electronic notebooks, portable televisions, portable radios, and the like. Type broadcast receivers, portable game machines, portable audio players, portable DVD players, cameras such as digital cameras, camcorder type video cameras, and the like.

  The pressure-sensitive adhesive sheet of the present invention is preferably used, for example, for adhering members and modules constituting a portable electronic device, fixing members and modules constituting a portable electronic device to a housing, and the like. More specifically, bonding a cover glass or lens (especially a glass lens) to a touch panel or a touch sensor, fixing a cover glass or lens (especially a glass lens) to a housing, fixing a display panel to a housing, Fixing input devices such as sheet-like keyboards and touch panels to the case, bonding the protective panel of the information display unit to the case, bonding the cases together, bonding the case and the decorative sheet, portable electronics Examples include fixing and bonding of various members and modules constituting the device. Note that in this specification, the display panel refers to a structure including at least a lens (particularly a glass lens) and a touch panel. In addition, the lens in the present specification is a concept including both a transparent body showing a light refraction action and a transparent body having no light refraction action. That is, the lens in the present specification includes a simple window panel having no refraction action.

  Furthermore, the pressure-sensitive adhesive sheet of the present invention is preferably used for optical applications. That is, the pressure-sensitive adhesive sheet of the present invention is preferably an optical pressure-sensitive adhesive sheet used for optical applications. More specifically, it is preferably used for, for example, an application for bonding an optical member (for optical member bonding) or a manufacturing application for a product (optical product) using the optical member.

[3. Optical member]
The optical member of the present invention is an optical member having at least the pressure-sensitive adhesive sheet and the substrate, and the substrate includes metal wiring (for example, copper wiring) on at least one surface, and on the surface of the substrate on the side having the metal wiring. As long as the above-mentioned pressure-sensitive adhesive layer (optical pressure-sensitive adhesive layer of the present invention) is attached to the film, there is no particular limitation in other respects. In addition, although the said adhesive sheet may be provided with the separator on the adhesive surface until use, since the said adhesive sheet in the optical member of this invention is an adhesive sheet at the time of use, it does not have a separator.

  Further, from the viewpoint of obtaining an excellent corrosion prevention effect, the optical member preferably has the pressure-sensitive adhesive layer on the side opposite to the side having the metal wiring of the substrate, and the side having the metal wiring of the substrate. More preferably, the pressure-sensitive adhesive layer is stuck on the opposite side of the surface.

  The material constituting the metal wiring is not particularly limited. For example, titanium, silicon, niobium, indium, zinc, tin, gold, silver, copper, aluminum, cobalt, chromium, nickel, lead, iron, palladium, platinum , Metals such as tungsten, zirconium, tantalum, and hafnium. Furthermore, the thing containing 2 or more types of these metals and the alloy which has these metals as a main component are mentioned. Among these, gold, silver, and copper are preferable from the viewpoint of conductivity, and copper is more preferable from the viewpoint of conductivity and cost. That is, the metal wiring is particularly preferably a copper wiring. The same applies to the material constituting the metal wiring of the touch panel described later.

  An optical member refers to a member having optical properties (for example, polarization, light refraction, light scattering, light reflection, light transmission, light absorption, light diffraction, optical rotation, visibility, etc.). . Although it does not specifically limit as a board | substrate which comprises the said optical member, For example, the board | substrate which comprises apparatuses (optical apparatus), such as a display apparatus (image display apparatus) and an input device, or the board | substrate used for these apparatuses is mentioned, For example, a polarizing plate, a wave plate, a retardation plate, an optical compensation film, a brightness enhancement film, a light guide plate, a reflection film, an antireflection film, a hard coat film (a hard coat treatment is applied to at least one surface of a plastic film such as a PET film. Film), transparent conductive film (for example, plastic film having an ITO layer on the surface (preferably, ITO film such as PET-ITO, polycarbonate, cycloolefin polymer), etc.), design film, decorative film, surface protection plate, prism , Lens, color filter, transparent substrate (glass sensor , Glass display panels (LCD, etc.), glass substrates such as glass plates with transparent electrodes, etc., and substrates on which these are laminated (these may be collectively referred to as “functional films”), etc. Is mentioned. These films may have a metal nanowire layer, a conductive polymer layer, or the like. Moreover, the metal fine wire may be mesh-printed on these films. In addition, said "plate" and "film" shall include forms, such as plate shape, film shape, and sheet shape, respectively, for example, "polarizing film" shall include "polarizing plate", "polarizing sheet", etc. . The “film” includes a film sensor and the like.

  Examples of the display device include a liquid crystal display device, an organic EL (electroluminescence) display device, a PDP (plasma display panel), and electronic paper. Moreover, a touch panel etc. are mentioned as said input device.

  Although it does not specifically limit as a board | substrate which comprises the said optical member, For example, board | substrates (For example, a sheet form, a film form, a plate-shaped board | substrate which consists of glass, an acrylic resin, a polycarbonate, a polyethylene terephthalate, a cycloolefin polymer, a metal thin film, etc. Etc.). In addition, as described above, the “optical member” in the present invention includes a member (design film, decorative film, surface protective film, etc.) that plays a role of decoration or protection while maintaining the visibility of the display device or the input device. Shall be.

  If the pressure-sensitive adhesive sheet of the present invention is a pressure-sensitive adhesive sheet with a base material and the pressure-sensitive adhesive sheet constitutes a member having optical properties, the base material can be equated with the substrate, and the pressure-sensitive adhesive sheet is the optical member of the present invention. But it can be said.

  When the pressure-sensitive adhesive sheet of the present invention is a pressure-sensitive adhesive sheet with a substrate, and the functional film is used as the substrate, the pressure-sensitive adhesive sheet of the present invention has the pressure-sensitive adhesive layer on at least one side of the functional film. It can also be used as an “adhesive functional film”.

  Next, a specific example of a particularly preferable aspect of the optical member of the present invention will be described with reference to the schematic diagram of FIG.

  FIG. 1A shows an optical member having at least a substrate that is a pressure-sensitive adhesive sheet 10 and a transparent conductive film 11. The transparent conductive film 11 includes a metal wiring 3 on one side, and the pressure-sensitive adhesive sheet 10 is a transparent conductive film 11. The optical member 1 stuck on the surface having the metal wiring 3 is described.

  FIG. 1B shows an optical member having at least a pressure-sensitive adhesive sheet 10 and a substrate that is a transparent substrate 12. The transparent substrate 12 includes a metal wiring 3 on one side, and the pressure-sensitive adhesive sheet 10 is a metal wiring of the transparent substrate 12. The optical member 1 stuck on the surface of the side having 3 is described.

  FIG. 1C shows an optical member having at least a substrate which is an adhesive sheet 10 and a film sensor 13, the film sensor 13 having a metal wiring 3 on one side, and the adhesive sheet 10 is a metal wiring of the film sensor 13. The optical member 1 stuck on the surface of the side having 3 is described.

[4. Touch panel]
The touch panel of the present invention is a touch panel having at least the pressure-sensitive adhesive sheet and the substrate, and the substrate includes a metal wiring (for example, a copper wiring) on one side, and the surface of the substrate on the side having the metal wiring is the above. The adhesive layer is not particularly limited as long as the adhesive layer is attached. In addition, since the said adhesive sheet in the touchscreen of this invention is an adhesive sheet at the time of use, it does not have a separator.

  As the touch panel, the optical member of the present invention is another optical member (the adhesive sheet may or may not necessarily have the adhesive sheet. It is preferable from the viewpoint of obtaining an effect. The other optical member may be singular or plural.

  The aspect of bonding the optical member of the present invention and the other optical member in the case of the above aspect is not particularly limited, but, for example, (1) the optical member of the present invention and the above through the adhesive sheet of the present invention An aspect in which another optical member is bonded, (2) an aspect in which the pressure-sensitive adhesive sheet of the present invention containing or constituting the optical member is bonded to the other optical member, and (3) an optical member through the pressure-sensitive adhesive sheet of the present invention (4) A mode in which the pressure-sensitive adhesive sheet of the present invention comprising or constituting the optical member is bonded to a member other than the optical member, and the like. In the above aspect (2), the pressure-sensitive adhesive sheet of the present invention is preferably a double-sided pressure-sensitive adhesive sheet whose base material is an optical member (for example, an optical film).

  Next, a specific example of a particularly preferable aspect of the touch panel of the present invention will be described with reference to the schematic diagram of FIG.

  FIG. 2A shows a touch panel 2 having a transparent substrate 12a, an adhesive sheet 10a, a transparent conductive film 11, an adhesive sheet 10b, and a transparent substrate 12b in contact with each other in this order. The transparent conductive film 11 includes the metal wiring 3 on the surface on the pressure-sensitive adhesive sheet 10 a side, and the pressure-sensitive adhesive sheet 10 a is adhered to the surface of the transparent conductive film 11 on the side having the metal wiring 3. The transparent substrate 12a and the transparent substrate 12b are preferably glass, and the transparent conductive film 11 is preferably PET-ITO. The pressure-sensitive adhesive sheet 10b may be the pressure-sensitive adhesive sheet of the present invention and may not be the pressure-sensitive adhesive sheet of the present invention, but is preferably the pressure-sensitive adhesive sheet of the present invention.

  FIG. 2B shows a touch panel 2 having a transparent substrate 12a, an adhesive sheet 10, a polarizing plate 14a, a transparent substrate 12b, and a polarizing plate 14b in contact with each other in this order. The transparent substrate 12a is provided with the metal wiring 3 on the surface on the pressure-sensitive adhesive sheet 10 side, and the pressure-sensitive adhesive sheet 10 is stuck on the surface of the transparent substrate 12a on the side having the metal wiring 3. The transparent substrate 12a is preferably a cover glass sensor, and the transparent substrate 12b is preferably a glass display panel such as an LCD.

  FIG. 2C shows a touch panel 2 having a transparent substrate 12a, an adhesive sheet 10a, a film sensor 13, an adhesive sheet 10b, a polarizing plate 14a, a transparent substrate 12b, and a polarizing plate 14b in contact with each other in this order. ing. The film sensor 13 includes the metal wiring 3 on the surface on the pressure-sensitive adhesive sheet 10 a side, and the pressure-sensitive adhesive sheet 10 a is attached to the surface of the film sensor 13 on the side having the metal wiring 3. The transparent substrate 12a is preferably glass, and the transparent substrate 12b is preferably a glass display panel such as an LCD. The pressure-sensitive adhesive sheet 10b may or may not be composed of the optical pressure-sensitive adhesive layer of the present invention, but is preferably composed of the optical pressure-sensitive adhesive layer of the present invention.

  2D, the transparent substrate 12a, the adhesive sheet 10a, the film sensor 13, the adhesive sheet 10b, the hard coat film 15, the adhesive sheet 10c, the polarizing plate 14a, the transparent substrate 12b, and the polarizing plate 14b are arranged in this order. A touch panel 2 that is in contact is described. The film sensor 13 includes the metal wiring 3 on the surface on the pressure-sensitive adhesive sheet 10 a side, and the pressure-sensitive adhesive sheet 10 a is attached to the surface of the film sensor 13 on the side having the metal wiring 3. The transparent substrate 12a is preferably glass, the transparent substrate 12b is preferably a glass display panel such as an LCD, and the hard coat film 15 is preferably a hard coat PET film. The pressure-sensitive adhesive sheets 10b and 10c may or may not be composed of the optical pressure-sensitive adhesive layer of the present invention, but are preferably composed of the optical pressure-sensitive adhesive layer of the present invention.

  FIG. 2E shows an optical member 4 having a transparent substrate 12a, an adhesive sheet 10a, a film sensor 13, an adhesive sheet 10b, and a hard coat film 15 in contact with each other in this order, a polarizing plate 14a, and a transparent substrate 12b. , And an optical member 5 having a polarizing plate 14b in contact with each other in this order. The optical member 4 and the optical member 5 are in a positional relationship in which the hard coat film 15 and the polarizing plate 14a face each other. The hard coat film 15 is not in contact with the polarizing plate 14a, and an air layer is formed between the hard coat film 15 and the polarizing plate 14a. The film sensor 13 includes the metal wiring 3 on the surface on the pressure-sensitive adhesive sheet 10 a side, and the pressure-sensitive adhesive sheet 10 a is attached to the surface of the film sensor 13 on the side having the metal wiring 3. The transparent substrate 12a is preferably glass, the transparent substrate 12b is preferably a glass display panel such as an LCD, and the hard coat film 15 is preferably a hard coat PET film. The pressure-sensitive adhesive sheets 10b and 10c may or may not be composed of the optical pressure-sensitive adhesive layer of the present invention, but are preferably composed of the optical pressure-sensitive adhesive layer of the present invention.

  Further, the metal wiring pattern (wiring example of metal wiring) is not particularly limited. For example, the metal wiring pattern shown in FIG. FIG. 7 is a schematic plan view showing an example of a metal wiring pattern. In FIG. 7, 71a to 76a are metal wirings (pattern wirings), 71b to 76b are metal wirings (pattern wirings), and 81 to 86 are electrodes (transparent electrodes). Each electrode is connected to a metal wiring. For example, the electrode 81 is connected to the metal wiring 71a and the metal wiring 72b. Moreover, in FIG. 7, although each electrode is patterned in strip shape, the shape of an electrode is not limited to strip shape. Furthermore, in FIG. 7, each electrode is connected to the metal wiring at two locations, but the number of metal wiring connection locations on the electrode is not particularly limited. For example, the electrode may be connected to the metal wiring at one place, or may be connected to the metal wiring at three or more places. If necessary, the metal wiring may be connected to a control means such as an IC.

  The method for forming the metal wiring pattern is not particularly limited, and examples thereof include a method of removing a previously provided metal layer by etching, a printing method, and the like.

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

(Acrylic polymer production example 1)
60 parts by weight of dicyclopentanyl methacrylate (DCPMA, dicyclopentanyl methacrylate), 40 parts by weight of methyl methacrylate (MMA, methyl methacrylate), 3.5 parts by weight of α-thioglycerol as a chain transfer agent and a polymerization solvent 100 parts by weight of toluene was put into a four-necked flask, and these were stirred at 70 ° C. for 1 hour in a nitrogen atmosphere. Next, 0.2 part by weight of 2,2′-azobisisobutyronitrile as a polymerization initiator is put into a four-necked flask and reacted at 70 ° C. for 2 hours, followed by reaction at 80 ° C. for 2 hours. I let you. Thereafter, the reaction solution was put in a 130 ° C. temperature atmosphere, and toluene, chain transfer agent and unreacted monomer were removed by drying to obtain a solid acrylic polymer. The acrylic polymer was referred to as “acrylic polymer (B-1)”.
The acrylic polymer (B-1) had a weight average molecular weight (Mw) of 5.1 × 10 ³ .

[Example 1]
A monomer mixture composed of 68 parts by weight of 2-ethylhexyl acrylate (2EHA), 14.5 parts by weight of N-vinyl-2-pyrrolidone (NVP), and 17.5 parts by weight of 2-hydroxyethyl acrylate (HEA) , 0.035 parts by weight of a photopolymerization initiator (trade name “Irgacure 184”, manufactured by BASF) and 0.035 parts by weight of a photopolymerization initiator (trade name “Irgacure 651”, manufactured by BASF) Ultraviolet rays were irradiated until the viscosity (BH viscometer No. 5 rotor, 10 rpm, measurement temperature 30 ° C.) reached about 20 Pa · s to obtain a prepolymer composition in which a part of the monomer component was polymerized.
Next, 100 parts by weight of the prepolymer composition, 5 parts by weight of the acrylic polymer (B-1), 0.075 parts by weight of hexanediol diacrylate (HDDA), a silane coupling agent (trade name “KBM-403 "0.3 parts by weight manufactured by Shin-Etsu Chemical Co., Ltd.) and 0.05 parts by weight of 1,2,3-benzotriazole (trade name" BT-120 ", manufactured by Johoku Chemical Industry Co., Ltd.) Thus, an adhesive composition (pre-curing composition) was obtained.

The pressure-sensitive adhesive composition was applied onto a polyethylene terephthalate (PET) separator (trade name “MRF50”, manufactured by Mitsubishi Plastics Co., Ltd.) so that the final thickness (the thickness of the pressure-sensitive adhesive layer) was 100 μm. (Adhesive composition layer) was formed. Next, a PET separator (trade name “MRF38”, manufactured by Mitsubishi Plastics, Inc.) was provided on the coating layer, and the coating layer was covered to block oxygen. And the laminated body of MRF50 / application layer (adhesive composition layer) / MRF38 was obtained.
Next, the laminated body was irradiated with ultraviolet rays having an illuminance of 5 mW / cm ² for 300 seconds from the upper surface (MRF38 side) of the laminated body with a black light (manufactured by Toshiba Corporation). Furthermore, the drying process was performed for 2 minutes with a 90 degreeC dryer, and the residual monomer was volatilized. And the base material-less double-sided adhesive sheet which consists only of an adhesive layer and in which both surfaces of the adhesive layer were protected with the separator was obtained.

[Example 2]
A substrate-less double-sided PSA sheet was obtained in the same manner as in Example 1 except that the amount of 1,2,3-benzotriazole used was 0.1 parts by weight.

[Example 3]
A substrate-less double-sided PSA sheet was obtained in the same manner as in Example 1 except that the amount of 1,2,3-benzotriazole used was 0.2 parts by weight.

[Example 4]
A baseless double-sided PSA sheet was obtained in the same manner as in Example 1 except that the amount of 1,2,3-benzotriazole used was 0.3 parts by weight and the thickness of the PSA layer was 50 μm.

[Example 5]
A substrate-less double-sided PSA sheet was obtained in the same manner as in Example 1 except that the amount of 1,2,3-benzotriazole used was 0.3 parts by weight.

[Example 6]
A baseless double-sided PSA sheet was obtained in the same manner as in Example 1 except that the amount of 1,2,3-benzotriazole used was 0.3 parts by weight and the thickness of the PSA layer was 150 μm.

[Example 7]
A substrate-less double-sided PSA sheet was obtained in the same manner as in Example 1 except that the amount of 1,2,3-benzotriazole used was 0.3 parts by weight and the thickness of the PSA layer was 250 μm.

[Example 8]
A substrate-less double-sided pressure-sensitive adhesive sheet was obtained in the same manner as in Example 1 except that the amount of 1,2,3-benzotriazole used was 0.5 parts by weight.

[Example 9]
A substrate-less double-sided pressure-sensitive adhesive sheet was obtained in the same manner as in Example 1, except that the amount of 1,2,3-benzotriazole used was 2.0 parts by weight.

[Example 10]
Instead of 1,2,3-benzotriazole, the same procedure as in Example 1 was performed except that 0.5 part by weight of 5-methylbenzotriazole (trade name “5M-BTA”, manufactured by Johoku Chemical Co., Ltd.) was used. Thus, a baseless double-sided pressure-sensitive adhesive sheet was obtained.

[Example 11]
Instead of 1,2,3-benzotriazole, 0.5 part by weight of 1- [N, N-bis (2-ethylhexyl) aminomethyl] benzotriazole (trade name “BT-LX”, manufactured by Johoku Chemical Industry Co., Ltd.) ) Was used in the same manner as in Example 1 to obtain a substrateless double-sided PSA sheet.

[Example 12]
Instead of 1,2,3-benzotriazole, 0.5 part by weight of 1- [N, N-bis (2-ethylhexyl) aminomethyl] methylbenzotriazole (trade name “TT-LX”, Johoku Chemical Industry Co., Ltd.) A substrate-less double-sided pressure-sensitive adhesive sheet was obtained in the same manner as in Example 1 except that the product was used.

[Example 13]
The amount of 1,2,3-benzotriazole used is 0.3 parts by weight, and the composition of the monomer mixture is 61 parts by weight of 2-ethylhexyl acrylate (2EHA), 14 parts by weight of N-vinyl-2-pyrrolidone (NVP). Parts and 4-hydroxybutyl acrylate (4HBA) 25 parts by weight, and the amount of hexanediol diacrylate (HDDA) was 0.060 parts by weight. A sheet was obtained.

[Example 14]
A baseless double-sided PSA sheet was obtained in the same manner as in Example 1 except that the amount of 1,2,3-benzotriazole used was 5.0 parts by weight.

[Example 15]
The amount of 1,2,3-benzotriazole used is 0.5 parts by weight, the acrylic polymer (B-1) is not used, and the composition of the monomer mixture is 78 parts by weight of 2-ethylhexyl acrylate (2EHA), A substrate-less double-sided pressure-sensitive adhesive sheet was obtained in the same manner as in Example 1 except that 18 parts by weight of N-vinyl-2-pyrrolidone (NVP) and 4 parts by weight of 2-hydroxyethyl acrylate (HEA) were used.

[Example 16]
Except for 0.250 parts by weight of hexanediol diacrylate (HDDA) and 0.3 parts by weight of 1,2,3-benzotriazole (trade name “BT-120”, manufactured by Johoku Chemical Industry Co., Ltd.) In the same manner as in Example 1, a pressure-sensitive adhesive composition (pre-curing composition) was obtained.
And using this composition, it carried out similarly to Example 1, and obtained the base material-less double-sided adhesive sheet which consists only of an adhesive layer and in which both surfaces of the adhesive layer were protected by the separator.

[Example 17]
61 parts by weight of 2-ethylhexyl acrylate (2EHA), 14 parts by weight of N-vinyl-2-pyrrolidone (NVP), 3 parts by weight of 2-hydroxyethyl acrylate (HEA), and 22 parts by weight of 4-hydroxybutyl acrylate (4HBA) Except having used the monomer mixture comprised from a part, it carried out similarly to Example 1, and obtained the prepolymer composition which a part of said monomer component superposed | polymerized.
Next, 0.180 parts by weight of hexanediol diacrylate (HDDA) and silane coupling agent (trade name “KBM-403”, manufactured by Shin-Etsu Chemical Co., Ltd.) are added to 100 parts by weight of the prepolymer composition. Part, and 1,2,3-benzotriazole (trade name “BT-120”, manufactured by Johoku Chemical Industry Co., Ltd.) 0.3 parts by weight are added and mixed to prepare a pressure-sensitive adhesive composition (pre-curing composition). Obtained.
And using this adhesive composition, it carried out similarly to Example 1, and obtained the base-material-less double-sided adhesive sheet which consists only of an adhesive layer and in which both surfaces of the adhesive layer were protected by the separator.

[Example 18]
61 parts by weight of 2-ethylhexyl acrylate (2EHA), 14 parts by weight of N-vinyl-2-pyrrolidone (NVP), 3 parts by weight of 2-hydroxyethyl acrylate (HEA), and 22 parts by weight of 4-hydroxybutyl acrylate (4HBA) Except having used the monomer mixture comprised from a part, it carried out similarly to Example 1, and obtained the prepolymer composition which a part of said monomer component superposed | polymerized.
Next, 0.060 parts by weight of hexanediol diacrylate (HDDA) and silane coupling agent (trade name “KBM-403”, manufactured by Shin-Etsu Chemical Co., Ltd.) are added to 100 parts by weight of the prepolymer composition. Part, and 1,2,3-benzotriazole (trade name “BT-120”, manufactured by Johoku Chemical Industry Co., Ltd.) 0.3 parts by weight are added and mixed to prepare a pressure-sensitive adhesive composition (pre-curing composition). Obtained.
And using this composition, it carried out similarly to Example 1, and obtained the base material-less double-sided adhesive sheet which consists only of an adhesive layer and in which both surfaces of the adhesive layer were protected by the separator.

[Comparative Example 1]
A substrate-less double-sided PSA sheet was obtained in the same manner as in Example 1 except that 1,2,3-benzotriazole was not used.

[Comparative Example 2]
Instead of 1,2,3-benzotriazole, 0.5 part by weight of pentaerythritol tetrakis [3- (3,5-di-tert-butyl-4-hydroxyphenyl) propionate] (trade name “Irganox 1010”, BASF A substrate-less double-sided pressure-sensitive adhesive sheet was obtained in the same manner as in Example 1 except that the product manufactured by Kogyo Co. was used.

[Comparative Example 3]
No 1,2,3-benzotriazole, no acrylic polymer (B-1), and the composition of the monomer mixture was 90 parts by weight of 2-ethylhexyl acrylate (2EHA) and 10 parts by weight of acrylic acid (AA). And double-sided adhesive without base material in the same manner as in Example 1 except that 0.070 parts by weight of dipentaerythritol hexaacrylate (DPHA) was used instead of 0.075 parts by weight of hexanediol diacrylate (HDDA). A sheet was obtained.

[Comparative Example 4]
The amount of 1,2,3-benzotriazole used is 0.5 parts by weight, the acrylic polymer (B-1) is not used, and the composition of the monomer mixture is 90 parts by weight of 2-ethylhexyl acrylate (2EHA) and Example 1 except that 10 parts by weight of acrylic acid (AA) and 0.070 parts by weight of dipentaerythritol hexaacrylate (DPHA) were used instead of 0.075 parts by weight of hexanediol diacrylate (HDDA) Similarly, a baseless double-sided pressure-sensitive adhesive sheet was obtained.

[Comparative Example 5]
It is composed of 60 parts by weight of lauryl acrylate (LA), 22 parts by weight of 2-ethylhexyl acrylate (2EHA), 10 parts by weight of N-vinyl-2-pyrrolidone (NVP), and 8 parts by weight of 4-hydroxybutyl acrylate (4HBA). A prepolymer composition in which a part of the monomer component was polymerized was obtained in the same manner as in Example 1 except that the monomer mixture was used.
Next, 100 parts by weight of the prepolymer composition, 0.035 parts by weight of dipentaerythritol hexaacrylate (DPHA), and a silane coupling agent (trade name “KBM-403”, manufactured by Shin-Etsu Chemical Co., Ltd.) 3 parts by weight was added and mixed to obtain an adhesive composition (pre-curing composition).
And using this composition, it carried out similarly to Example 1, and obtained the base material-less double-sided adhesive sheet which consists only of an adhesive layer and in which both surfaces of the adhesive layer were protected by the separator.

[Comparative Example 6]
The amount of 1,2,3-benzotriazole used is 0.3 parts by weight, and the composition of the monomer mixture is 60 parts by weight of lauryl acrylate (LA), 22 parts by weight of 2-ethylhexyl acrylate (2EHA), N-vinyl. 2-pyrrolidone (NVP) 10 parts by weight and 4-hydroxybutyl acrylate (4HBA) 8 parts by weight, and dipentaerythritol hexaacrylate (DPHA) instead of 0.075 parts by weight of hexanediol diacrylate (HDDA) A substrate-less double-sided PSA sheet was obtained in the same manner as in Example 1 except that 0.035 parts by weight was used.

[Characteristic evaluation]
The following measurement or evaluation was performed about the base-material-less double-sided adhesive sheet of an Example and a comparative example. The evaluation results are shown in Table 2.

(1) Metal corrosive film (hereinafter referred to as “copper film”) in which a copper layer is provided on one surface of a cycloolefin (COP) base material (trade name “ZEONOR”, manufactured by ZEON CORPORATION, thickness 100 μm). In some cases, one separator of the double-sided pressure-sensitive adhesive sheet is peeled off on the substrate surface side, and the double-sided pressure-sensitive adhesive sheet is pressure-bonded and bonded under the conditions of a 2 kg roller and one reciprocating pressure, and the copper film and the double-sided pressure-sensitive adhesive sheet are laminated. A structure A having a structure was obtained.
Next, after cutting out the structure A into a size of 15 mm × 15 mm, the separator of the double-sided pressure-sensitive adhesive sheet is peeled off, a soda glass plate (25 mm × 25 mm, thickness 0.7 mm), a 2 kg roller, and a reciprocating pressure condition And then bonded together. And the structure B which has a laminated structure of a copper film, a double-sided adhesive sheet, and glass was obtained.
Separately, a film (trade name “DSC-03”, manufactured by Dai Nippon Printing Co., Ltd., thickness 90 μm, hereinafter referred to as “AR film”) provided with an antireflection treatment layer on one surface of a triacetylcellulose (TAC) substrate. In some cases, the separator of one side of the same double-sided pressure-sensitive adhesive sheet as described above is peeled off, and the double-sided pressure-sensitive adhesive sheet is pressure-bonded and bonded under the conditions of a 2 kg roller and one reciprocating pressure, A structure C having a laminated structure of double-sided PSA sheets was obtained. Next, after the structure C is cut out to a size of 10 mm × 10 mm, the separator of the double-sided pressure-sensitive adhesive sheet is peeled off and bonded to the central part on the copper surface side of the structure B under a 2 kg roller and one reciprocating pressure bonding condition. In addition, a structure D having a laminated structure composed of five layers of an AR film, a double-sided PSA sheet, a copper film, a double-sided PSA sheet, and glass was obtained.
After being left for 30 minutes in an atmosphere of 23 ° C. and 50% RH, the structure D was put into an autoclave and autoclaved for 15 minutes at a temperature of 50 ° C. and a pressure of 0.5 MPa. After the autoclave treatment, the structure D was taken out from the autoclave and allowed to stand for 24 hours in an atmosphere of 23 ° C. and 50% RH (RH: relative humidity).
As an apparatus for measuring the sheet resistance value of the copper layer of the structure D, a Hall effect measuring apparatus (trade name “HL5500PC”, manufactured by Toago Technology Co., Ltd.) was used. Under an atmosphere of 23 ° C. and 50% RH, the sheet resistance value (initial sheet resistance: R ₀ ) of the structure D was measured.
After measurement, in order to prevent the oxidation of the copper on the part to which the measurement probe is applied, the copper surface on which the AR film of the structure D is not attached is covered for 300 hours in an environment of 85 ° C. and 85% RH. did. After taking out, temperature control and humidity control were performed for 24 hours in an environment of 23 ° C. and 50% RH. After visually confirming the color change of copper from the initial stage, the sheet resistance value (post-test sheet resistance: R ₁ ) was measured in an atmosphere of 23 ° C. and 50% RH.
From the initial sheet resistance value (R ₀ ) and the value of the post-test sheet resistance value (R ₁ ) after 300 hours in an environment of 85 ° C. and 85% RH, the change rate T of the sheet resistance value is obtained by the following formula. It was.
Rate of change T (%) = (R ₁ −R ₀ ) / R ₀ × 100
If the change rate T of the sheet resistance value was less than 150%, it was determined to be acceptable (“◯”) and to have good corrosion prevention performance. On the other hand, if the rate of change in resistance value from the initial stage was 150% or more, it was judged as rejected ("x") and judged not to have good corrosion prevention performance.

(2) Total light transmittance and haze One separator was peeled off from the double-sided pressure-sensitive adhesive sheet, and the double-sided pressure-sensitive adhesive sheet was slid into glass (manufactured by Matsunami Glass Industry Co., Ltd., “White Polishing No. 1”, thickness 0.8 to 1.0 mm, total light transmittance 92%, haze 0.2%), and the other separator was peeled off to produce a test piece having a double-sided pressure-sensitive adhesive sheet (adhesive layer) / slide glass layer structure. did.
The total light transmittance and haze in the visible light region of the test piece were measured using a haze meter (device name “HM-150”, manufactured by Murakami Color Research Co., Ltd.).

(3) 180 ° peel adhesion (180 ° peel adhesion to glass plate)
A sheet piece having a length of 100 mm and a width of 20 mm was cut out from the double-sided pressure-sensitive adhesive sheet. Next, one separator was peeled from the sheet piece, and a PET film (trade name “Lumirror S-10”, thickness 25 μm, manufactured by Toray Industries, Inc.) was attached (backed). Next, the other separator was peeled off and pressure-bonded to a test plate under the conditions of a 2 kg roller and one reciprocating pressure. Thereafter, aging is performed for 30 minutes in an atmosphere of 23 ° C. and 50% RH. After aging, using a tensile tester (device name “Autograph AG-IS”, manufactured by Shimadzu Corporation), in accordance with JIS Z0237, under an atmosphere of 23 ° C. and 50% RH, a tensile speed of 300 mm / min, peeling Under the condition of an angle of 180 °, the pressure-sensitive adhesive sheet was peeled off from the test plate, and the adhesive strength (N / 20 mm) was measured by peeling it 180 °.
A glass plate (trade name “Soda Lime Glass # 0050”, produced by Matsunami Glass Industry Co., Ltd.) was used as a test plate.

(4) Humidity and cloudiness resistance After the double-sided PSA sheet was cut out to a size of 45 mm in width and 90 mm in length, one separator was peeled off, and a soda glass plate (manufactured by Matsunami Glass Industrial Co., Ltd., 100 mm × 50 mm, thickness 0. 7 mm) and bonded under pressure under the conditions of a 2 kg roller and one reciprocating pressure. Next, the separator is peeled off from the bonded double-sided pressure-sensitive adhesive sheet, and the same glass plate as described above is bonded using a vacuum bonding apparatus under conditions of a surface pressure of 0.2 MPa, a degree of vacuum of 30 Pa, and a bonding time of 10 seconds. An evaluation sample having a configuration of glass / double-sided PSA sheet / glass was obtained.
Next, the evaluation sample was put into an autoclave and autoclaved for 15 minutes under the conditions of a temperature of 50 ° C. and a pressure of 0.5 MPa. After the autoclave treatment, an evaluation sample was taken out and left for 24 hours in an atmosphere of 23 ° C. and 50% RH (RH: relative humidity).
The evaluation sample was placed in a high-temperature and high-humidity environment of 60 ° C. and 95% RH for 300 hours, then taken out, left in a 23 ° C. and 50% RH environment for 24 hours, and then the appearance of the evaluation sample was visually observed. The humidified cloudiness resistance was evaluated according to the evaluation criteria.
Evaluation criteria A: No whitening B: Whitening is observed only at the four corners of the double-sided PSA sheet C: Whitening is observed on the entire double-sided PSA sheet

(5) Anti-foaming peelability One separator of the double-sided pressure-sensitive adhesive sheet is peeled off, and the double-sided pressure-sensitive adhesive sheet is replaced with one of a cycloolefin (COP) substrate (trade name “ZEONOR”, manufactured by Nippon Zeon Co., Ltd., thickness 100 μm). A film with an ITO (indium and tin oxide) layer on its surface (hereinafter sometimes referred to as “COP-ITO film”) is bonded to the surface on the ITO layer side using a 2 kg roller and one reciprocating pressure condition. And pasted together. And structure A 'which has a laminated structure of a COP-ITO film and a double-sided adhesive sheet was obtained.
Next, the separator of the double-sided pressure-sensitive adhesive sheet in the structure A ′ is peeled off, and the structure A ′ is pressure-bonded to the surface of the stepped glass (see FIGS. 4 to 6) with a 2 kg roller and one reciprocation. Bonded by pressing under conditions. And structure B 'which has a laminated structure of a COP-ITO film, a double-sided adhesive sheet, and a stepped glass was obtained.
The structure B ′ was allowed to stand for 1 hour in an atmosphere of 23 ° C. and 50% RH, and then the structure B ′ was put into an autoclave and autoclaved for 15 minutes at a temperature of 50 ° C. and a pressure of 0.5 MPa. After the autoclave treatment, the structure B ′ was removed from the autoclave, and the structure B ′ was put into a dryer set at 85 ° C. and left for 24 hours.
Thereafter, the structure B ′ was taken out from the dryer and left for 30 minutes in an atmosphere of 23 ° C. and 50% RH. And the presence or absence of foaming (foaming including foaming caused by foreign matter) or peeling in the structure B ′ was confirmed by a microscope. And it evaluated by the following evaluation criteria.
Evaluation criteria A: No foaming or peeling is observed B: Foaming is observed only due to foreign matter having a size of 100 μm or more C: Foaming is observed due to foreign matter having a size of less than 100 μm D: Foreign matter Foaming or peeling is seen regardless of the presence or absence of

  In addition, the evaluation of (5) anti-foaming peel-off property is carried out by using an ITO (indium and tin oxide) layer on one surface of a polyethylene terephthalate (PET) substrate (thickness 50 μm) instead of a COP-ITO film. It was also performed when the provided film (hereinafter sometimes referred to as “PET-ITO film”) was used.

(6) Visual evaluation of pattern Film formation by sputtering is performed on one surface of a film substrate (biaxially stretched polyethylene terephthalate (PET) film having a thickness of 23 μm, trade name “Diafoil”, manufactured by Mitsubishi Plastics, Inc.). An ITO film (ITO layer) having a thickness of 22 nm was formed to obtain a film (ITO film) having an ITO film formed on one surface of the film substrate.
Next, the ITO film was cut into a sheet having a width of 6 cm and a length of 10 cm. A plurality of polyimide tapes having a width of 2 mm were bonded to the surface of the cut ITO film at intervals of 2 mm. Bonding of the polyimide tape was performed so that the length direction of the polyimide tape and the width direction of the cut ITO film were in the same direction. After bonding the polyimide tape, it was immersed for 10 minutes in a 5 wt% hydrochloric acid aqueous solution heated to 50 ° C. This immersion corresponds to an etching process for the purpose of removing the ITO film in the non-masking part (the part where the polyimide tape is not bonded). After immersing in a 5 wt% hydrochloric acid aqueous solution, it was washed with water by immersing in a sufficient amount of pure water, and the polyimide tape was slowly peeled off.
And it heated for 5 minutes in 70 degreeC oven, it dried, and the film (ITO pattern film) which has the patterned ITO film | membrane was obtained.
The ITO pattern film has a pattern forming portion where the ITO film is formed and a pattern opening where the ITO film is removed.

After providing the copper wiring so that it may connect to the edge part of each pattern from the peripheral part of a surface in which the ITO pattern of the said ITO pattern film is formed, and a peripheral part, it is a glass plate through a double-sided adhesive sheet on the said surface Were laminated to obtain a test piece (a laminated body having a laminated structure of an ITO pattern film provided with a glass plate / double-sided pressure-sensitive adhesive sheet / copper wiring).
In addition, the copper wiring provided so that it may connect to the edge part of each pattern from the peripheral part and peripheral part of the surface in which the ITO pattern of the said ITO pattern film is formed is common in the aspect shown in FIG.

Next, the test piece was left in an environment of 85 ° C. and 85% RH for 48 hours. About the test piece after standing, the visibility of a pattern was confirmed visually and evaluated by the following evaluation criteria.
Evaluation criteria Very good (◎): It is difficult to discriminate between the pattern forming portion and the pattern opening, and the pattern is hardly visible.
Good (◯): The pattern forming portion and the pattern opening can be slightly discriminated, and the pattern is slightly visible.
Defect (x): The pattern forming portion and the pattern opening can be clearly distinguished, and the pattern is clearly visible.

  According to the optical pressure-sensitive adhesive layer of the present invention, adhesion reliability, transparency, and corrosion prevention effects can be achieved, and furthermore, the occurrence of swell in a high-temperature environment can be suppressed, and the coating of a protective layer is not required and the number of processes is reduced. As a result, the cost is reduced and the yield is improved, which is useful for a display device such as a liquid crystal display (LCD), an input device such as a touch panel, particularly for a touch panel.

1, 4, 5 Optical member 2 Touch panel 3 Metal wiring 10, 10a, 10b, 10c Adhesive sheet 11 Transparent conductive film 12a, 12b Transparent substrate 13 Film sensor 14a, 14b Polarizing plate 15 Hard coat film 20 Stepped glass (step test piece )
21 Glass plate 22 Step 6 Laminated body 61 Support body 62 Metal film 71a, 72a, 73a, 74a, 75a, 76a Metal wiring (pattern wiring)
71b, 72b, 73b, 74b, 75b, 76b Metal wiring (pattern wiring)
81, 82, 83, 84, 85, 86 Electrode (transparent electrode)

Claims (14)

It contains a base polymer and a rust preventive agent, does not contain or substantially does not contain an acidic group-containing monomer as a monomer component constituting the base polymer, and an elastic modulus at 85 ° C. is 5.0 × 10 ⁴ Pa or more. A pressure-sensitive adhesive layer for optical use. 4. An acrylic polymer (A) and a rust preventive agent are contained, a carboxyl group-containing monomer is not contained or substantially not contained as a monomer component constituting the acrylic polymer (A), and an elastic modulus at 85 ° C. is 5. An optical pressure-sensitive adhesive layer characterized by being 0 × 10 ⁴ Pa or more.   The optical pressure-sensitive adhesive layer according to claim 2, comprising 5 parts by weight or more of a hydroxyl group-containing monomer with respect to the total amount (100 parts by weight) of monomer components constituting the acrylic polymer (A).   The optical pressure-sensitive adhesive layer according to claim 2 or 3, comprising 5 parts by weight or more of a nitrogen atom-containing monomer with respect to the total amount (100 parts by weight) of monomer components constituting the acrylic polymer (A).   The optical pressure-sensitive adhesive layer according to claim 1, wherein the rust inhibitor is a benzotriazole-based compound.   The optical pressure-sensitive adhesive layer according to any one of claims 1 to 5, wherein haze (according to JIS K7136) is 1.0% or less.   The optical pressure-sensitive adhesive layer according to any one of claims 1 to 6, wherein the total light transmittance (according to JIS K7361-1) is 90% or more.   A pressure-sensitive adhesive sheet comprising the optical pressure-sensitive adhesive layer according to claim 1.   The pressure-sensitive adhesive sheet according to claim 8, which has a 180 ° peeling adhesion to a glass plate of 8 N / 20 mm or more.   The pressure-sensitive adhesive sheet according to claim 8 or 9, having a thickness of 12 to 350 µm.   An optical member comprising at least the adhesive sheet according to any one of claims 8 to 10 and a substrate, wherein the substrate is provided with metal wiring on at least one side, and on the surface of the substrate on the side having the metal wiring. An optical member to which the pressure-sensitive adhesive sheet is adhered.   The optical member according to claim 11, wherein the metal wiring is a copper wiring.   A touch panel comprising at least the adhesive sheet according to any one of claims 8 to 10 and a substrate, wherein the substrate is provided with metal wiring on at least one side, and the surface of the substrate on the side having the metal wiring is provided. A touch panel with an adhesive sheet.   The touch panel according to claim 13, wherein the metal wiring is a copper wiring.

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