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TWI747995B - Polarizing plate with adhesive and image display device - Google Patents

Polarizing plate with adhesive and image display device Download PDF

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Publication number
TWI747995B
TWI747995B TW106139847A TW106139847A TWI747995B TW I747995 B TWI747995 B TW I747995B TW 106139847 A TW106139847 A TW 106139847A TW 106139847 A TW106139847 A TW 106139847A TW I747995 B TWI747995 B TW I747995B
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Taiwan
Prior art keywords
adhesive
adhesive layer
polarizing plate
adhesive sheet
sheet
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TW106139847A
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Chinese (zh)
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TW201826583A (en
Inventor
寶田翔
澤﨑良平
保井淳
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日商日東電工股份有限公司
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Publication of TWI747995B publication Critical patent/TWI747995B/en

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    • G—PHYSICS
    • G02—OPTICS
    • G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
    • G02B5/00—Optical elements other than lenses
    • G02B5/30—Polarising elements
    • G02B5/3025—Polarisers, i.e. arrangements capable of producing a definite output polarisation state from an unpolarised input state
    • G02B5/3033—Polarisers, i.e. arrangements capable of producing a definite output polarisation state from an unpolarised input state in the form of a thin sheet or foil, e.g. Polaroid
    • G—PHYSICS
    • G02—OPTICS
    • G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
    • G02B5/00—Optical elements other than lenses
    • G02B5/30—Polarising elements
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B32—LAYERED PRODUCTS
    • B32B—LAYERED PRODUCTS, i.e. PRODUCTS BUILT-UP OF STRATA OF FLAT OR NON-FLAT, e.g. CELLULAR OR HONEYCOMB, FORM
    • B32B23/00—Layered products comprising a layer of cellulosic plastic substances, i.e. substances obtained by chemical modification of cellulose, e.g. cellulose ethers, cellulose esters, viscose
    • B32B23/04—Layered products comprising a layer of cellulosic plastic substances, i.e. substances obtained by chemical modification of cellulose, e.g. cellulose ethers, cellulose esters, viscose comprising such cellulosic plastic substance as the main or only constituent of a layer, which is next to another layer of the same or of a different material
    • B32B23/08—Layered products comprising a layer of cellulosic plastic substances, i.e. substances obtained by chemical modification of cellulose, e.g. cellulose ethers, cellulose esters, viscose comprising such cellulosic plastic substance as the main or only constituent of a layer, which is next to another layer of the same or of a different material of synthetic resin
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B32—LAYERED PRODUCTS
    • B32B—LAYERED PRODUCTS, i.e. PRODUCTS BUILT-UP OF STRATA OF FLAT OR NON-FLAT, e.g. CELLULAR OR HONEYCOMB, FORM
    • B32B23/00—Layered products comprising a layer of cellulosic plastic substances, i.e. substances obtained by chemical modification of cellulose, e.g. cellulose ethers, cellulose esters, viscose
    • B32B23/20—Layered products comprising a layer of cellulosic plastic substances, i.e. substances obtained by chemical modification of cellulose, e.g. cellulose ethers, cellulose esters, viscose comprising esters
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B32—LAYERED PRODUCTS
    • B32B—LAYERED PRODUCTS, i.e. PRODUCTS BUILT-UP OF STRATA OF FLAT OR NON-FLAT, e.g. CELLULAR OR HONEYCOMB, FORM
    • B32B27/00—Layered products comprising a layer of synthetic resin
    • B32B27/06—Layered products comprising a layer of synthetic resin as the main or only constituent of a layer, which is next to another layer of the same or of a different material
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B32—LAYERED PRODUCTS
    • B32B—LAYERED PRODUCTS, i.e. PRODUCTS BUILT-UP OF STRATA OF FLAT OR NON-FLAT, e.g. CELLULAR OR HONEYCOMB, FORM
    • B32B27/00—Layered products comprising a layer of synthetic resin
    • B32B27/06—Layered products comprising a layer of synthetic resin as the main or only constituent of a layer, which is next to another layer of the same or of a different material
    • B32B27/08—Layered products comprising a layer of synthetic resin as the main or only constituent of a layer, which is next to another layer of the same or of a different material of synthetic resin
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B32—LAYERED PRODUCTS
    • B32B—LAYERED PRODUCTS, i.e. PRODUCTS BUILT-UP OF STRATA OF FLAT OR NON-FLAT, e.g. CELLULAR OR HONEYCOMB, FORM
    • B32B27/00—Layered products comprising a layer of synthetic resin
    • B32B27/30—Layered products comprising a layer of synthetic resin comprising vinyl (co)polymers; comprising acrylic (co)polymers
    • B32B27/302—Layered products comprising a layer of synthetic resin comprising vinyl (co)polymers; comprising acrylic (co)polymers comprising aromatic vinyl (co)polymers, e.g. styrenic (co)polymers
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B32—LAYERED PRODUCTS
    • B32B—LAYERED PRODUCTS, i.e. PRODUCTS BUILT-UP OF STRATA OF FLAT OR NON-FLAT, e.g. CELLULAR OR HONEYCOMB, FORM
    • B32B27/00—Layered products comprising a layer of synthetic resin
    • B32B27/30—Layered products comprising a layer of synthetic resin comprising vinyl (co)polymers; comprising acrylic (co)polymers
    • B32B27/306—Layered products comprising a layer of synthetic resin comprising vinyl (co)polymers; comprising acrylic (co)polymers comprising vinyl acetate or vinyl alcohol (co)polymers
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B32—LAYERED PRODUCTS
    • B32B—LAYERED PRODUCTS, i.e. PRODUCTS BUILT-UP OF STRATA OF FLAT OR NON-FLAT, e.g. CELLULAR OR HONEYCOMB, FORM
    • B32B27/00—Layered products comprising a layer of synthetic resin
    • B32B27/30—Layered products comprising a layer of synthetic resin comprising vinyl (co)polymers; comprising acrylic (co)polymers
    • B32B27/308—Layered products comprising a layer of synthetic resin comprising vinyl (co)polymers; comprising acrylic (co)polymers comprising acrylic (co)polymers
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B32—LAYERED PRODUCTS
    • B32B—LAYERED PRODUCTS, i.e. PRODUCTS BUILT-UP OF STRATA OF FLAT OR NON-FLAT, e.g. CELLULAR OR HONEYCOMB, FORM
    • B32B27/00—Layered products comprising a layer of synthetic resin
    • B32B27/36—Layered products comprising a layer of synthetic resin comprising polyesters
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B32—LAYERED PRODUCTS
    • B32B—LAYERED PRODUCTS, i.e. PRODUCTS BUILT-UP OF STRATA OF FLAT OR NON-FLAT, e.g. CELLULAR OR HONEYCOMB, FORM
    • B32B27/00—Layered products comprising a layer of synthetic resin
    • B32B27/36—Layered products comprising a layer of synthetic resin comprising polyesters
    • B32B27/365—Layered products comprising a layer of synthetic resin comprising polyesters comprising polycarbonates
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B32—LAYERED PRODUCTS
    • B32B—LAYERED PRODUCTS, i.e. PRODUCTS BUILT-UP OF STRATA OF FLAT OR NON-FLAT, e.g. CELLULAR OR HONEYCOMB, FORM
    • B32B33/00—Layered products characterised by particular properties or particular surface features, e.g. particular surface coatings; Layered products designed for particular purposes not covered by another single class
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B32—LAYERED PRODUCTS
    • B32B—LAYERED PRODUCTS, i.e. PRODUCTS BUILT-UP OF STRATA OF FLAT OR NON-FLAT, e.g. CELLULAR OR HONEYCOMB, FORM
    • B32B7/00—Layered products characterised by the relation between layers; Layered products characterised by the relative orientation of features between layers, or by the relative values of a measurable parameter between layers, i.e. products comprising layers having different physical, chemical or physicochemical properties; Layered products characterised by the interconnection of layers
    • B32B7/04—Interconnection of layers
    • B32B7/12—Interconnection of layers using interposed adhesives or interposed materials with bonding properties
    • C—CHEMISTRY; METALLURGY
    • C09—DYES; PAINTS; POLISHES; NATURAL RESINS; ADHESIVES; COMPOSITIONS NOT OTHERWISE PROVIDED FOR; APPLICATIONS OF MATERIALS NOT OTHERWISE PROVIDED FOR
    • C09J—ADHESIVES; NON-MECHANICAL ASPECTS OF ADHESIVE PROCESSES IN GENERAL; ADHESIVE PROCESSES NOT PROVIDED FOR ELSEWHERE; USE OF MATERIALS AS ADHESIVES
    • C09J11/00—Features of adhesives not provided for in group C09J9/00, e.g. additives
    • C09J11/02—Non-macromolecular additives
    • C09J11/06—Non-macromolecular additives organic
    • C—CHEMISTRY; METALLURGY
    • C09—DYES; PAINTS; POLISHES; NATURAL RESINS; ADHESIVES; COMPOSITIONS NOT OTHERWISE PROVIDED FOR; APPLICATIONS OF MATERIALS NOT OTHERWISE PROVIDED FOR
    • C09J—ADHESIVES; NON-MECHANICAL ASPECTS OF ADHESIVE PROCESSES IN GENERAL; ADHESIVE PROCESSES NOT PROVIDED FOR ELSEWHERE; USE OF MATERIALS AS ADHESIVES
    • C09J121/00—Adhesives based on unspecified rubbers
    • C—CHEMISTRY; METALLURGY
    • C09—DYES; PAINTS; POLISHES; NATURAL RESINS; ADHESIVES; COMPOSITIONS NOT OTHERWISE PROVIDED FOR; APPLICATIONS OF MATERIALS NOT OTHERWISE PROVIDED FOR
    • C09J—ADHESIVES; NON-MECHANICAL ASPECTS OF ADHESIVE PROCESSES IN GENERAL; ADHESIVE PROCESSES NOT PROVIDED FOR ELSEWHERE; USE OF MATERIALS AS ADHESIVES
    • C09J123/00—Adhesives based on homopolymers or copolymers of unsaturated aliphatic hydrocarbons having only one carbon-to-carbon double bond; Adhesives based on derivatives of such polymers
    • C09J123/02—Adhesives based on homopolymers or copolymers of unsaturated aliphatic hydrocarbons having only one carbon-to-carbon double bond; Adhesives based on derivatives of such polymers not modified by chemical after-treatment
    • C09J123/18—Homopolymers or copolymers of hydrocarbons having four or more carbon atoms
    • C09J123/20—Homopolymers or copolymers of hydrocarbons having four or more carbon atoms having four to nine carbon atoms
    • C09J123/22—Copolymers of isobutene; Butyl rubber ; Homo- or copolymers of other iso-olefines
    • C—CHEMISTRY; METALLURGY
    • C09—DYES; PAINTS; POLISHES; NATURAL RESINS; ADHESIVES; COMPOSITIONS NOT OTHERWISE PROVIDED FOR; APPLICATIONS OF MATERIALS NOT OTHERWISE PROVIDED FOR
    • C09J—ADHESIVES; NON-MECHANICAL ASPECTS OF ADHESIVE PROCESSES IN GENERAL; ADHESIVE PROCESSES NOT PROVIDED FOR ELSEWHERE; USE OF MATERIALS AS ADHESIVES
    • C09J133/00—Adhesives based on homopolymers or copolymers of compounds having one or more unsaturated aliphatic radicals, each having only one carbon-to-carbon double bond, and at least one being terminated by only one carboxyl radical, or of salts, anhydrides, esters, amides, imides, or nitriles thereof; Adhesives based on derivatives of such polymers
    • C—CHEMISTRY; METALLURGY
    • C09—DYES; PAINTS; POLISHES; NATURAL RESINS; ADHESIVES; COMPOSITIONS NOT OTHERWISE PROVIDED FOR; APPLICATIONS OF MATERIALS NOT OTHERWISE PROVIDED FOR
    • C09J—ADHESIVES; NON-MECHANICAL ASPECTS OF ADHESIVE PROCESSES IN GENERAL; ADHESIVE PROCESSES NOT PROVIDED FOR ELSEWHERE; USE OF MATERIALS AS ADHESIVES
    • C09J153/00—Adhesives based on block copolymers containing at least one sequence of a polymer obtained by reactions only involving carbon-to-carbon unsaturated bonds; Adhesives based on derivatives of such polymers
    • C09J153/02—Vinyl aromatic monomers and conjugated dienes
    • C09J153/025—Vinyl aromatic monomers and conjugated dienes modified
    • C—CHEMISTRY; METALLURGY
    • C09—DYES; PAINTS; POLISHES; NATURAL RESINS; ADHESIVES; COMPOSITIONS NOT OTHERWISE PROVIDED FOR; APPLICATIONS OF MATERIALS NOT OTHERWISE PROVIDED FOR
    • C09J—ADHESIVES; NON-MECHANICAL ASPECTS OF ADHESIVE PROCESSES IN GENERAL; ADHESIVE PROCESSES NOT PROVIDED FOR ELSEWHERE; USE OF MATERIALS AS ADHESIVES
    • C09J7/00—Adhesives in the form of films or foils
    • C09J7/20—Adhesives in the form of films or foils characterised by their carriers
    • G—PHYSICS
    • G06—COMPUTING OR CALCULATING; COUNTING
    • G06F—ELECTRIC DIGITAL DATA PROCESSING
    • G06F3/00—Input arrangements for transferring data to be processed into a form capable of being handled by the computer; Output arrangements for transferring data from processing unit to output unit, e.g. interface arrangements
    • G06F3/01—Input arrangements or combined input and output arrangements for interaction between user and computer
    • G06F3/03—Arrangements for converting the position or the displacement of a member into a coded form
    • G06F3/041—Digitisers, e.g. for touch screens or touch pads, characterised by the transducing means
    • G06F3/0412—Digitisers structurally integrated in a display
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B32—LAYERED PRODUCTS
    • B32B—LAYERED PRODUCTS, i.e. PRODUCTS BUILT-UP OF STRATA OF FLAT OR NON-FLAT, e.g. CELLULAR OR HONEYCOMB, FORM
    • B32B2307/00—Properties of the layers or laminate
    • B32B2307/70—Other properties
    • B32B2307/726—Permeability to liquids, absorption
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B32—LAYERED PRODUCTS
    • B32B—LAYERED PRODUCTS, i.e. PRODUCTS BUILT-UP OF STRATA OF FLAT OR NON-FLAT, e.g. CELLULAR OR HONEYCOMB, FORM
    • B32B2457/00—Electrical equipment
    • B32B2457/20—Displays, e.g. liquid crystal displays, plasma displays
    • B32B2457/202—LCD, i.e. liquid crystal displays
    • C—CHEMISTRY; METALLURGY
    • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
    • C08K—Use of inorganic or non-macromolecular organic substances as compounding ingredients
    • C08K5/00—Use of organic ingredients
    • C08K5/16—Nitrogen-containing compounds
    • C08K5/34—Heterocyclic compounds having nitrogen in the ring
    • C08K5/3467—Heterocyclic compounds having nitrogen in the ring having more than two nitrogen atoms in the ring
    • C08K5/3472—Five-membered rings
    • C08K5/3475—Five-membered rings condensed with carbocyclic rings
    • C—CHEMISTRY; METALLURGY
    • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
    • C08K—Use of inorganic or non-macromolecular organic substances as compounding ingredients
    • C08K5/00—Use of organic ingredients
    • C08K5/16—Nitrogen-containing compounds
    • C08K5/34—Heterocyclic compounds having nitrogen in the ring
    • C08K5/3467—Heterocyclic compounds having nitrogen in the ring having more than two nitrogen atoms in the ring
    • C08K5/3477—Six-membered rings
    • C08K5/3492—Triazines
    • C—CHEMISTRY; METALLURGY
    • C09—DYES; PAINTS; POLISHES; NATURAL RESINS; ADHESIVES; COMPOSITIONS NOT OTHERWISE PROVIDED FOR; APPLICATIONS OF MATERIALS NOT OTHERWISE PROVIDED FOR
    • C09J—ADHESIVES; NON-MECHANICAL ASPECTS OF ADHESIVE PROCESSES IN GENERAL; ADHESIVE PROCESSES NOT PROVIDED FOR ELSEWHERE; USE OF MATERIALS AS ADHESIVES
    • C09J2301/00—Additional features of adhesives in the form of films or foils
    • C09J2301/20—Additional features of adhesives in the form of films or foils characterized by the structural features of the adhesive itself
    • C09J2301/208—Additional features of adhesives in the form of films or foils characterized by the structural features of the adhesive itself the adhesive layer being constituted by at least two or more adjacent or superposed adhesive layers, e.g. multilayer adhesive
    • C—CHEMISTRY; METALLURGY
    • C09—DYES; PAINTS; POLISHES; NATURAL RESINS; ADHESIVES; COMPOSITIONS NOT OTHERWISE PROVIDED FOR; APPLICATIONS OF MATERIALS NOT OTHERWISE PROVIDED FOR
    • C09J—ADHESIVES; NON-MECHANICAL ASPECTS OF ADHESIVE PROCESSES IN GENERAL; ADHESIVE PROCESSES NOT PROVIDED FOR ELSEWHERE; USE OF MATERIALS AS ADHESIVES
    • C09J2301/00—Additional features of adhesives in the form of films or foils
    • C09J2301/30—Additional features of adhesives in the form of films or foils characterized by the chemical, physicochemical or physical properties of the adhesive or the carrier
    • C09J2301/312—Additional features of adhesives in the form of films or foils characterized by the chemical, physicochemical or physical properties of the adhesive or the carrier parameters being the characterizing feature

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  • Chemical & Material Sciences (AREA)
  • Organic Chemistry (AREA)
  • Physics & Mathematics (AREA)
  • Engineering & Computer Science (AREA)
  • General Physics & Mathematics (AREA)
  • General Engineering & Computer Science (AREA)
  • Theoretical Computer Science (AREA)
  • Optics & Photonics (AREA)
  • Human Computer Interaction (AREA)
  • Chemical Kinetics & Catalysis (AREA)
  • Polarising Elements (AREA)
  • Liquid Crystal (AREA)
  • Laminated Bodies (AREA)
  • Adhesives Or Adhesive Processes (AREA)
  • Adhesive Tapes (AREA)

Abstract

本發明之附黏著劑之偏光板(1)具備：包含含碘之聚乙烯醇系膜之偏光元件(11)、貼合於偏光元件之第一主面之透明保護膜(15)、及與偏光元件之第二主面相接而設置之正面側黏著片(20)。正面側黏著片為積層有至少2層之黏著劑層之積層黏著片，且具備與偏光元件相接而配置之第一黏著劑層(21)及與偏光元件隔開而配置之第二黏著劑層(22)。較佳為正面側黏著片之80℃下之儲存模數G'80 為1×105 Pa以下，且第一黏著劑層之透濕度較佳為150 g/m2 ･24 h以下。The adhesive-attached polarizing plate (1) of the present invention includes: a polarizing element (11) containing a polyvinyl alcohol film containing iodine, a transparent protective film (15) attached to the first main surface of the polarizing element, and The front side adhesive sheet (20) is arranged in contact with the second main surface of the polarizing element. The front side adhesive sheet is a laminated adhesive sheet in which at least two adhesive layers are laminated, and is provided with a first adhesive layer (21) arranged in contact with the polarizing element and a second adhesive arranged apart from the polarizing element Layer (22). Preferably stored under the front side of the adhesive sheet 80 ℃ modulus G '80 to 1 × 10 5 Pa or less, and the first adhesive layer of the moisture permeability is preferably 150 g / m 2 · 24 h or less.

Description

附黏著劑之偏光板及圖像顯示裝置Polarizing plate with adhesive and image display device

本發明係關於一種用於形成於圖像顯示面板之正面具備透明板或觸控面板等之圖像顯示裝置的附黏著劑之偏光板。進而，本發明係關於一種使用該附黏著劑之偏光板之圖像顯示裝置。The present invention relates to an adhesive-attached polarizing plate used in an image display device with a transparent plate or a touch panel on the front of an image display panel. Furthermore, the present invention relates to an image display device using the polarizing plate with the adhesive.

作為行動電話、智慧型手機、汽車導航裝置、個人電腦用顯示器、電視等各種圖像顯示裝置，正廣泛使用液晶顯示裝置或有機EL (Electroluminescence，電致發光)顯示裝置。為了防止因來自外表面之衝擊導致圖像顯示面板之破損等，有時於圖像顯示面板之視認側設置透明樹脂板或玻璃板等正面透明板(亦被稱為「視窗層」等)。又，近年來，於圖像顯示面板之視認側具備觸控面板之裝置得到普及。 作為於圖像顯示面板之正面配置正面透明板或觸控面板等正面透明構件之方法，業界提出有經由黏著劑將配置於圖像顯示面板之視認側表面之偏光板與正面透明構件貼合的「層間填充構造」。於層間填充構造中，偏光板與正面透明構件之間由黏著劑填充，因此，界面之折射率差減小，抑制由反射或散射引起之視認性之降低。 於正面透明構件之面板側之面之周緣部，形成有旨在裝飾或遮光之著色層(加飾印刷層)。若於具有加飾印刷層之透明構件貼合黏著劑，則容易在印刷階差部之周邊產生氣泡。又，介隔黏著劑對印刷階差部正下方之圖像顯示面板施加局部之應力，於畫面端部產生力學應變，因此存在於畫面之周緣部產生顯示不均之情況。 為了解決由印刷階差引起之該等問題，層間填充劑使用柔軟且厚度較大之黏著片(例如參照專利文獻1)。專利文獻2中提出有一種雙面附黏著劑之膜，其於偏光板之一面具備用以與圖像顯示面板貼合之黏著劑層，且於另一面具備具有特定之儲存模數之層間填充用黏著劑層。 [先前技術文獻] [專利文獻] [專利文獻1]日本專利特開 2011-219665號公報 [專利文獻2]日本專利特開2014-115468號公報As various image display devices such as mobile phones, smart phones, car navigation devices, personal computer monitors, and televisions, liquid crystal display devices or organic EL (Electroluminescence) display devices are being widely used. In order to prevent damage to the image display panel due to impact from the outer surface, a front transparent plate (also called a "window layer", etc.) such as a transparent resin plate or a glass plate is sometimes installed on the viewing side of the image display panel. In addition, in recent years, devices equipped with a touch panel on the viewing side of an image display panel have become popular. As a method of arranging front transparent components such as a front transparent plate or a touch panel on the front of an image display panel, the industry has proposed a method of bonding the polarizing plate arranged on the visible side surface of the image display panel and the front transparent member through an adhesive. "Interlayer filling structure". In the interlayer filling structure, the adhesive is filled between the polarizing plate and the front transparent member. Therefore, the refractive index difference of the interface is reduced, and the decrease in visibility caused by reflection or scattering is suppressed. A colored layer (decorated printing layer) for decoration or shading is formed on the peripheral edge of the panel side of the front transparent member. If the adhesive is attached to a transparent member with a decorative printing layer, bubbles are likely to be generated around the printing step. In addition, the interposed adhesive exerts a local stress on the image display panel directly below the printing step, and mechanical strain is generated at the end of the screen, so there is a situation where display unevenness occurs at the periphery of the screen. In order to solve these problems caused by the printing level difference, the interlayer filler uses a soft and thick adhesive sheet (for example, refer to Patent Document 1). Patent Document 2 proposes a double-sided adhesive film, which is provided with an adhesive layer on one side of the polarizing plate for bonding with the image display panel, and on the other side with an interlayer filling with a specific storage modulus Use an adhesive layer. [Prior Art Document] [Patent Document] [Patent Document 1] Japanese Patent Laid-Open No. 2011-219665 [Patent Document 2] Japanese Patent Laid-Open No. 2014-115468

[發明所要解決之課題] 於多用於室外之行動電話、智慧型手機等之移動顯示器用途中，廣泛採用使用有黏著劑之層間填充構造。於移動顯示器中，對構成元件之薄型化、輕量化之要求較高，且亦對採用層間填充構造之顯示器要求薄型化。然而，由於對用作層間填充劑之黏著劑層要求階差吸收性，故而黏著劑層之薄型化存在極限。 本發明者等人嘗試藉由使用僅於偏光元件之單面具有保護膜之單面保護偏光板作為設置於圖像顯示面板之視認側的偏光板，在偏光元件上直接積層作為層間填充劑之黏著劑來謀求薄型化。然而，於偏光元件上不介隔保護膜而設置先前之層間填充用黏著片之構成中，判明於加濕耐久試驗中偏光元件褪色，耐久性存在問題。鑒於該課題，本發明之目的在於提供一種能夠兼顧圖像顯示裝置之薄型化與加濕耐久性之附黏著劑之偏光板。 [用於解決課題之手段] 藉由於偏光板上設置將低透濕度之黏著劑層與具有特定之黏彈性行為之黏著劑層積層而得之積層黏著片，能夠解決上述課題。 本發明之附黏著劑之偏光板具備：包含含碘之聚乙烯醇系膜之偏光元件、貼合於偏光元件之第一主面之透明保護膜、及與偏光元件之第二主面相接而設置之正面側黏著片。正面側黏著片為積層有至少2層之黏著劑層之積層黏著片，且具備與偏光元件相接而配置之第一黏著劑層及與偏光元件隔開而配置之第二黏著劑層。 關於正面側黏著片，較佳為80℃下之儲存模數G'80 為1×105 Pa以下。關於正面側黏著片，較佳為透濕度為150 g/m2 ･24 h以下。正面側黏著片之厚度較佳為250 μm以下。關於正面側黏著片，較佳為80℃下之儲存模數G'80 與25℃下之儲存模數G'25 之比G'25 /G'80 為2~100。 關於正面側黏著片，較佳為波長380 nm下之透光率為15%以下。例如，藉由第一黏著劑層及第二黏著劑層中之至少一者含有紫外線吸收劑，可對正面側黏著片賦予紫外線吸收性。 關於與偏光元件相接而設置之第一黏著劑層，較佳為透濕度為150 g/m2 ･24 h以下。第一黏著劑層之厚度較佳為50 μm以下。為了以較小之厚度實現低透濕度，第一黏著劑層較佳為含有橡膠系聚合物作為主成分之黏著劑層。第一黏著劑層之80℃下之儲存模數G'80 與25℃下之儲存模數G'25 之比G'25 /G'80 可為3以下。 關於與偏光元件隔開而設置(設置於靠近正面透明構件之側)之第二黏著劑層，較佳為厚度為50 μm以上。較佳為第二黏著劑層之厚度大於第一黏著劑層之厚度。 關於第二黏著劑層，較佳為25℃下之儲存模數G'25 為1×104 Pa以上，較佳為80℃下之儲存模數G'80 為1×105 Pa以下。關於第二黏著劑層，較佳為80℃下之儲存模數G'80 與25℃下之儲存模數G'25 之比G'25 /G'80 為3.5以上。第二黏著劑層較佳為含有丙烯酸系聚合物作為主成分之黏著劑層。 本發明之附黏著劑之偏光板較佳為配置於正面透明板或觸控面板與圖像顯示單元之間使用。本發明之附黏著劑之偏光板可為於透明保護膜上進而具備單元側黏著片之雙面附黏著劑之偏光板。 進而，本發明係關於一種於圖像顯示單元之表面具備上述附黏著劑之偏光板、及正面透明構件之圖像顯示裝置。於本發明之圖像顯示裝置中，偏光板與正面透明板或觸控面板等正面透明構件係藉由正面側黏著片而貼合。 [發明之效果] 關於本發明之附黏著劑之偏光板，於僅於偏光元件之單面設置有透明保護膜之單面保護偏光板之偏光元件上不介隔透明保護膜而設置有正面側黏著片。因此，有助於在正面透明構件與圖像顯示單元之間具備偏光板之圖像顯示裝置之薄型化。由於正面側黏著片之第一黏著劑層之透濕度較低，故而即使於圖像顯示裝置暴露於高濕度環境之情形時，亦可抑制水分向偏光元件之轉移，不易產生偏光元件之褪色。又，藉由於第一黏著片上具有第二黏著片，正面側黏著片具有階差吸收性，能夠抑制在正面透明構件之印刷階差附近之氣泡之混入或圖像顯示裝置之顯示不均。[Problem to be solved by the invention] For mobile display applications such as mobile phones and smart phones that are mostly used outdoors, an interlayer filling structure with adhesive is widely used. In mobile displays, the requirements for thinner and lighter components are high, and the displays with interlayer filling structures are also required to be thinner. However, since the adhesive layer used as the interlayer filler requires step absorbency, there is a limit to the thinning of the adhesive layer. The inventors tried to use a single-sided protective polarizing plate with a protective film on only one side of the polarizing element as the polarizing plate installed on the viewing side of the image display panel, and directly layer the polarizing element as an interlayer filler. Adhesive to seek thinning. However, in the configuration in which the adhesive sheet for interlayer filling was provided without intervening the protective film on the polarizing element, it was found that the polarizing element was discolored during the humidification endurance test, and there was a problem in durability. In view of this problem, the object of the present invention is to provide an adhesive-attached polarizing plate capable of achieving both thinning of an image display device and humidification durability. [Means for Solving the Problem] The above-mentioned problem can be solved by a laminated adhesive sheet obtained by laminating an adhesive layer with low moisture permeability and an adhesive with specific viscoelastic behavior on the polarizing plate. The polarizing plate with adhesive of the present invention includes: a polarizing element containing a polyvinyl alcohol-based film containing iodine, a transparent protective film attached to the first main surface of the polarizing element, and a second main surface connected to the polarizing element And set the front side adhesive sheet. The front side adhesive sheet is a laminated adhesive sheet in which at least two adhesive layers are laminated, and is provided with a first adhesive layer arranged in contact with the polarizing element and a second adhesive layer arranged apart from the polarizing element. On the front side of the adhesive sheet, preferably 80 deg.] C under the storage modulus G '80 to 1 × 10 5 Pa or less. Regarding the front side pressure-sensitive adhesive sheet, the moisture permeability is preferably 150 g/m 2 ･24 h or less. The thickness of the front-side adhesive sheet is preferably 250 μm or less. On the front side of the adhesive sheet, preferably 80 deg.] C under the storage modulus G '80 to the storage at 25 deg.] C modulus G' ratio of G 25 '25 / G' 80 2 to 100. Regarding the front side adhesive sheet, the light transmittance at a wavelength of 380 nm is preferably 15% or less. For example, when at least one of the first adhesive layer and the second adhesive layer contains an ultraviolet absorber, ultraviolet absorption can be imparted to the front-side adhesive sheet. Regarding the first adhesive layer provided in contact with the polarizing element, the moisture permeability is preferably 150 g/m 2 ･24 h or less. The thickness of the first adhesive layer is preferably 50 μm or less. In order to achieve low moisture permeability with a small thickness, the first adhesive layer is preferably an adhesive layer containing a rubber-based polymer as a main component. Storage under the first adhesive layer of 80 deg.] C modulus G '80 to the storage at 25 deg.] C modulus G' ratio of G 25 '25 / G' 80 may be 3 or less. Regarding the second adhesive layer provided apart from the polarizing element (provided on the side close to the front transparent member), the thickness is preferably 50 μm or more. Preferably, the thickness of the second adhesive layer is greater than the thickness of the first adhesive layer. On the second adhesive layer, preferably 25 deg.] C under the storage modulus G '25 of more than 1 × 10 4 Pa, preferably 80 deg.] C under the storage modulus G' 80 to 1 × 10 5 Pa or less. On the second adhesive layer, preferably 80 deg.] C under the storage modulus G '80 to the storage at 25 deg.] C modulus G' ratio of G 25 '25 / G' 80 is 3.5 or more. The second adhesive layer is preferably an adhesive layer containing an acrylic polymer as a main component. The polarizing plate with adhesive of the present invention is preferably used between the front transparent plate or the touch panel and the image display unit. The adhesive-attached polarizing plate of the present invention can be a double-sided adhesive-attached polarizing plate with a cell-side adhesive sheet on the transparent protective film. Furthermore, the present invention relates to an image display device provided with the above-mentioned polarizing plate with adhesive and a front transparent member on the surface of an image display unit. In the image display device of the present invention, the polarizing plate and the front transparent member such as the front transparent plate or the touch panel are bonded by the front side adhesive sheet. [Effects of the Invention] Regarding the adhesive-attached polarizing plate of the present invention, the polarizing element of the single-sided protective polarizing plate provided with a transparent protective film on only one side of the polarizing element is provided with a front side without intervening the transparent protective film Adhesive sheet. Therefore, it contributes to the thinning of the image display device provided with the polarizing plate between the front transparent member and the image display unit. Since the moisture permeability of the first adhesive layer of the front side adhesive sheet is low, even when the image display device is exposed to a high-humidity environment, the transfer of moisture to the polarizing element can be suppressed, and the fading of the polarizing element is unlikely to occur. In addition, since the first adhesive sheet has the second adhesive sheet, the front-side adhesive sheet has step absorbency, which can suppress the mixing of air bubbles near the printing step of the front transparent member or the display unevenness of the image display device.

圖1係表示附黏著劑之偏光板之一形態之剖視圖。附黏著劑之偏光板1於偏光板10之第一主面上具備正面側黏著片20。正面側黏著片20係於圖像顯示裝置之形成中用以將正面透明構件貼合於偏光板之視認側之黏著片。正面側黏著片20為具有與偏光板10之偏光元件11相接而配置之第一黏著劑層21及設置於第一黏著劑層21上之第二黏著劑層22之積層構成，且第一黏著劑層21係與偏光板10之偏光元件11相接而配置。 圖2係表示於視認側表面具備正面透明構件之圖像顯示裝置之一形態的模式性剖視圖。圖像顯示裝置100中，於在透明板71上設置有印刷部76之正面透明構件70與圖像顯示單元60之間配置有偏光板10。偏光板10與圖像顯示單元60經由單元側黏著片30而貼合，偏光板10與正面透明構件70經由正面側黏著片20而貼合。 [單面保護偏光板] 作為偏光板10，使用僅於偏光元件11之單面貼合有透明保護膜15者(以下，有時將僅於偏光元件之單面設置有透明保護膜之偏光板10記載為「單面保護偏光板」)。藉由使用單面保護偏光板作為配置於圖像顯示單元之視認側之偏光板，能夠使圖像顯示裝置薄型化。 ＜偏光元件＞ 偏光元件11為含有碘之聚乙烯醇系膜。作為應用於偏光元件之聚乙烯醇系膜之材料，使用聚乙烯醇或其衍生物。作為聚乙烯醇之衍生物，可列舉聚乙烯醇縮甲醛、聚乙烯醇縮乙醛等，此外還可列舉經乙烯、丙烯等烯烴、丙烯酸、甲基丙烯酸、丁烯酸等不飽和羧酸及其烷基酯、丙烯醯胺等改性者。聚乙烯醇通常使用聚合度為1000~10000左右、皂化度為80莫耳%~100莫耳%左右者。 藉由對聚乙烯醇系膜實施碘染色及拉伸處理，而獲得偏光元件。偏光元件之厚度較佳為1 μm~50 μm左右。作為偏光元件，亦可使用厚度為10 μm以下之薄型偏光元件。作為薄型偏光元件，例如可列舉日本專利特開昭51-069644號公報、日本專利特開2000-338329號公報、WO2010/100917號、日本專利第4691205號說明書、日本專利第4751481號說明書等中記載之偏光元件。此種薄型偏光元件例如可藉由包括將聚乙烯醇系樹脂層與延伸用樹脂基材以積層體之狀態進行延伸之步驟、及進行碘染色之步驟之製法而獲得。 ＜透明保護膜＞ 於偏光元件11之一面(第一主面)設置用以保護偏光元件11之透明保護膜15。透明保護膜15亦可具有以擴大視角等為目的之光學補償膜、用以與偏光元件11一併構成圓偏光板之1/4波長板等之功能。 作為構成透明保護膜15之材料，例如可列舉透明性、機械強度及熱穩定性優異之樹脂材料。作為此種樹脂材料之具體例，可列舉：三乙醯纖維素等纖維素系樹脂、聚酯系樹脂、聚醚碸系樹脂、聚碸系樹脂、聚碳酸酯系樹脂、聚醯胺系樹脂、聚醯亞胺系樹脂、聚烯烴系樹脂、(甲基)丙烯酸系樹脂、環狀聚烯烴系樹脂(降𦯉烯系樹脂)、聚芳酯系樹脂、聚苯乙烯系樹脂、聚乙烯醇系樹脂及該等之混合物。透明保護膜15之厚度並無特別限制，就強度或操作性等作業性、薄膜性等觀點而言，較佳為5~100 μm左右。偏光元件11與透明保護膜15較佳為經由適當之接著劑層(未圖示)進行貼合。 [正面側黏著片] 本發明之附黏著劑之偏光板於單面保護偏光板10之未設置透明保護膜15之側之面具備正面側黏著片20。正面側黏著片20用於將正面透明構件70貼合於單面保護偏光板10之視認側。正面側黏著片20為具備至少2層黏著劑層之積層黏著片。第一黏著劑層21係與偏光元件11相接而設置，且於第一黏著劑層21上設置有第二黏著劑層22。於正面側黏著片20包含第一黏著劑層21及第二黏著劑層22之兩層之情形時，附黏著劑之偏光板1於單面保護偏光板10上依序具備第一黏著劑層21及第二黏著劑層22。 正面側黏著片20較佳為透濕度為150 g/m2 ･24 h以下。藉由與偏光元件11相接而設置低透濕度之正面側黏著片20，能夠降低水分自外部向偏光元件11之轉移，能夠抑制高濕度環境下之偏光元件之劣化。正面側黏著片20較佳為80℃下之儲存模數G'80 為1×105 Pa以下。藉由於偏光板10與正面透明構件70之貼合時使用高溫下之儲存模數較小之正面側黏著片20，而具有階差吸收性，即使於正面透明構件70具有印刷階差之情形時，亦可抑制印刷階差附近之氣泡混入或由應力應變導致顯示不均之產生。就薄型化之觀點而言，正面側黏著片20之厚度較佳為250 μm以下。 ＜第一黏著劑層＞ 與偏光元件11相接而配置之第一黏著劑層21較佳為透濕度為150 g/m2 ･24 h以下。藉由與偏光元件11相接而設置低透濕度之黏著劑層，即使於圖像顯示裝置暴露於高濕度環境之情形時，亦可抑制偏光元件11之劣化。第一黏著劑層21之透濕度更佳為120 g/m2 ･24 h以下，進而較佳為100 g/m2 ･24 h以下，尤佳為60 g/m2 ･24 h以下，最佳為40 g/m2 ･24 h以下。透濕度為根據JIS Z0208之透濕度試驗(杯式法)測定之值，且係於40℃、92%之相對濕度下在24 h內透過面積1 m2 之試樣之水蒸氣之重量。 於單面保護偏光板10之透明保護膜15附設面貼合有圖像顯示單元60、且於單面保護偏光板10之偏光元件11經由正面側黏著片20貼合有正面透明構件70的圖像顯示裝置100中，水分有可能自透明保護膜15附設面(第一主面)及正面側黏著片20附設面(第二主面)轉移至偏光元件11。單面保護偏光板通常有水分自未設置透明保護膜之第二主面側向偏光元件之轉移量變大之傾向。 認為水分自第二主面側向偏光元件11之轉移有水分自正面側黏著片20之附設面(主面)之轉移及水分自正面側黏著片20之側面之轉移。於視認側表面設置有正面透明板或觸控面板等正面透明構件之圖像顯示裝置中，正面透明構件70具有抑制水分自圖像顯示裝置之主面滲入之作用。因此，能夠某種程度地抑制水分自第二主面之正面側黏著片附設面之轉移。另一方面，設置於偏光板10與正面透明構件70之間之作為層間填充劑之正面側黏著片20由於使厚度增大而具有階差吸收性，故而存在水分經由正面側黏著片20之側面向偏光元件11之轉移量變大。 於單面保護偏光板上配置有先前之層間填充用黏著片之情形時，因自黏著片之側面轉移至偏光元件之水分之影響，而於偏光元件之端面附近容易產生褪色。相對於此，藉由與偏光元件11相接而設置低透濕之第一黏著劑層21，可降低水分經由正面側黏著片20之側面向偏光元件11之轉移量，能夠抑制由水分引起之偏光元件之劣化。於第二黏著劑層22之透濕度較大之情形時，存在水分自第二黏著劑層22之側面滲入，但滲入至第二黏著劑層22之水分由低透濕之第一黏著劑層21阻斷，故而抑制向偏光元件11之轉移。因此，若第一黏著劑層21為低透濕，則即使於正面側黏著片20之厚度較大之情形時，亦可降低水分向偏光元件11之轉移，能夠抑制偏光元件之劣化。 就薄型化之觀點而言，第一黏著劑層21之厚度d1 較佳為50 μm以下，更佳為40 μm以下，進而較佳為35 μm以下。就薄型化之觀點而言，較佳為第一黏著劑層之厚度儘可能小。另一方面，透濕度與厚度存在反比關係，包含相同材料之片狀物有隨著厚度之減小，而透濕度增大之傾向。為了將透濕度設為上述範圍，第一黏著劑層21之厚度較佳為5 μm以上，更佳為10 μm以上。 第一黏著劑層21之25℃下之儲存模數G'25 較佳為1×104 Pa~1×108 Pa，更佳為5×104 Pa~1×107 Pa，進而較佳為1×105 Pa~5×106 Pa。第一黏著劑層21之80℃下之儲存模數G'80 較佳為5×103 Pa~5×107 Pa，更佳為1×104 Pa~5×106 Pa，進而較佳為3×104 Pa~1×106 Pa。 (第一黏著劑層之組成) 構成第一黏著劑層21之黏著劑只要滿足上述之透濕度，則其組成並無特別限定，可適當選擇使用以丙烯酸系聚合物、橡膠系聚合物、矽酮系聚合物、聚酯、聚胺酯、聚醯胺、聚乙烯基醚、乙酸乙烯酯/氯乙烯共聚物、改性聚烯烴、環氧系、氟型等聚合物作為基礎聚合物者。正面側黏著片配置於圖像顯示裝置之正面，因此較佳為第一黏著劑層21及第二黏著劑層22之光學透明性優異。具體而言，較佳為第一黏著劑層21及第二黏著劑層22各自之霧度為1.0%以下、全光線透過率為90%以上。 就即使以較小之厚度亦能夠實現低透濕度之方面而言，第一黏著劑層21較佳為含有橡膠系聚合物作為主成分之橡膠系黏著劑層。此處，「主成分」係指於第一黏著劑層中(或者，以用於形成第一黏著劑層之黏著劑組合物之總固形物成分為基準)含有40重量%以上之橡膠系聚合物。 橡膠系聚合物係於室溫附近之溫度範圍內顯示出橡膠彈性之聚合物。作為橡膠系聚合物而言，較佳為使用選自由天然橡膠、合成橡膠及熱塑性彈性體所構成之群中之一種以上。 作為合成橡膠，可列舉：聚異丁烯(PIB)、丁二烯橡膠(BR)、異戊二烯橡膠(IR)、異丁烯-異戊二烯橡膠(IIR)、苯乙烯-丁二烯橡膠(SBR)、氯丁二烯橡膠(CR)、丙烯腈-丁二烯橡膠(NBR)、丁二烯-異戊二烯-苯乙烯無規共聚物、異戊二烯-苯乙烯無規共聚物、二元系乙烯-丙烯橡膠(EPR)、三元系乙烯-丙烯橡膠(EPT)、丙烯酸系橡膠、聚胺酯橡膠等。該等之中，就透明性、耐光性之觀點而言，較佳為聚異丁烯(PIB)及丁基橡膠(IIR)，尤佳為聚異丁烯(PIB)。 作為熱塑性彈性體，例如可列舉：包含苯乙烯-乙烯-丁烯-苯乙烯嵌段共聚物(SEBS)、苯乙烯-異戊二烯-苯乙烯嵌段共聚物(SIS)、苯乙烯-丁二烯-苯乙烯嵌段共聚物(SBS)、苯乙烯-乙烯-丙烯-苯乙烯嵌段共聚物(SEPS；SIS之氫化物)、苯乙烯-乙烯-丙烯嵌段共聚物(SEP；苯乙烯-異戊二烯嵌段共聚物之氫化物)、苯乙烯-異丁烯-苯乙烯嵌段共聚物(SIBS)等苯乙烯系嵌段共聚物之苯乙烯系熱塑性彈性體；聚胺酯系熱塑性彈性體；聚酯系熱塑性彈性體；聚丙烯與EPT(三元系乙烯-丙烯橡膠)之聚合物摻合物等摻合系熱塑性彈性體等。該等之中，就透明性及耐光性之觀點而言，較佳為苯乙烯系熱塑性彈性體，尤佳為苯乙烯-乙烯-丙烯-苯乙烯嵌段共聚物(SEPS)。 ＜第二黏著劑層＞ 與偏光元件11間隔而配置之第二黏著劑層22具有對正面側黏著片20賦予階差吸收性之作用。為了具有階差吸收性，第二黏著劑層22較佳為80℃下之儲存模數G'80 為1.5×105 Pa以下，更佳為1×105 Pa以下，進而較佳為7×104 Pa以下。於第二黏著劑層22之高溫下之儲存模數較低之情形時，在真空加熱或利用高壓釜進行加熱貼合時之流動性較高，黏著劑容易進入階差附近，因此能夠抑制在階差附近混入氣泡。 於貼合時之加熱狀態下，為了抑制黏著劑自偏光板端面之溢出，第二黏著劑層22之G'80 較佳為1×103 Pa以上，更佳為3×103 Pa以上。 第二黏著劑層22之25℃下之儲存模數G'25 較佳為1×104 Pa~1×107 Pa，更佳為4×104 Pa~6×106 Pa，進而較佳為6×104 Pa~1×106 Pa。若常溫下之儲存模數為1×104 Pa以上，則能夠減少將附黏著劑之偏光板切割成特定尺寸時黏著劑在切割刀等上之附著、或黏著劑自端面之溢出。若常溫下之儲存模數為1×107 Pa以下，則可防止將附黏著劑之偏光板切割成特定尺寸時之切割面中黏著劑之破裂或缺損等。又，若第二黏著劑層22之G'25 為上述範圍，則可保持加工性或操作性等所需之凝集力，並且確保貼合時之初始黏著性。 第二黏著劑層22較佳為80℃下之儲存模數G'80 與25℃下之儲存模數G'25 的比G'25 /G'80 為3.5以上，更佳為5以上，進而較佳為7以上。於儲存模數之溫度依存性較大、G'25 /G'80 之值較大之情形時，常溫下之流動性較小，能夠抑制切割時黏著劑向切割刀等之轉移及黏著劑自端面之溢出，並且在加熱時流動性較高，黏著劑亦容易進入印刷階差附近，因此能夠抑制於印刷階差附近之氣泡混入或圖像顯示裝置之顯示不均。第二黏著劑層22之G'25 /G'80 之上限並無特別限制，若考慮常溫下之貼合時之黏著性或加熱時之流動性等，則較佳為100以下，更佳為50以下。 儲存模數G'藉由讀取根據JIS K7244-1「塑膠-動態機械特性之試驗方法」中記載之方法、於頻率1 Hz之條件下在-50℃~150℃之範圍內以5℃/分鐘之升溫速度進行測定時之特定溫度下的值而求出。 構成黏著劑層之黏著劑為光硬化型或熱硬化型，於偏光板10與正面透明構件70之貼合後進行硬化之情形時，只要硬化前(貼合時)之黏著劑之儲存模數(G'25 、G'80 及G'25 /G'80 )為上述範圍即可。由於黏著片之切割及與正面透明構件之貼合係於硬化前實施，故而藉由調整硬化前之第二黏著劑層22之儲存模數，可達成上述目的。 為了具有階差吸收性，第二黏著劑層22之厚度d2 較佳為50 μm以上，更佳為60 μm以上，進而較佳為70 μm以上。藉由增大第二黏著劑層22之厚度，可提高階差吸收性，能夠抑制於印刷階差附近之氣泡混入或圖像顯示裝置之顯示不均。第二黏著劑層22之厚度d2 之上限並無特別限定，就薄型化之觀點及防止黏著劑自端面溢出等觀點而言，較佳為250 μm以下，更佳為200 μm以下，進而較佳為180 μm以下。 (第二黏著劑層之組成) 構成第二黏著劑層22之黏著劑只要為滿足上述特性者，則其組成並無特別限定，可適當選擇使用以丙烯酸系聚合物、橡膠系聚合物、矽酮系聚合物、聚酯、聚胺酯、聚醯胺、聚乙烯基醚、乙酸乙烯酯/氯乙烯共聚物、改性聚烯烴、環氧系、氟系等聚合物作為基礎聚合物者。如上所述，第二黏著劑層較佳為光學透明性優異。 就可兼顧能夠賦予階差吸收性之黏彈特性與高透明性之方面而言，第二黏著劑層22較佳為含有丙烯酸系聚合物作為主成分之丙烯酸系黏著劑層。此處，「主成分」係指於第二黏著劑層中(或者，以用於形成第二黏著劑層之黏著劑組合物之總固形物成分為基準)含有40重量%以上之丙烯酸系聚合物。 作為丙烯酸系聚合物，較佳為使用以(甲基)丙烯酸烷基酯之單體單元作為主骨架者。再者，本說明書中，「(甲基)丙烯酸」係指丙烯酸及/或甲基丙烯酸。 作為(甲基)丙烯酸烷基酯，較佳為使用烷基之碳數為1~20之(甲基)丙烯酸烷基酯。上述(甲基)丙烯酸烷基酯之含量相對於構成丙烯酸系聚合物之單體成分總量，較佳為40重量%以上，更佳為50重量%以上，進而較佳為60重量%以上。丙烯酸系聚合物亦可為複數種(甲基)丙烯酸烷基酯之共聚物。構成單體單元之排列可為無規，亦可為嵌段。 (甲基)丙烯酸烷基酯之烷基可具有分支。藉由使用具有分支之(甲基)丙烯酸烷基酯，容易對黏著劑賦予柔軟性，可容易地形成具有上述儲存模數之丙烯酸系黏著劑層。作為(甲基)丙烯酸分支烷基酯，可較佳地使用(甲基)丙烯酸2-乙基己酯、(甲基)丙烯酸異辛酯、(甲基)丙烯酸異壬酯、(甲基)丙烯酸異癸酯、(甲基)丙烯酸異十四烷基酯、(甲基)丙烯酸異十八烷基酯等。 丙烯酸系聚合物較佳為含有具有可交聯之官能基之丙烯酸系單體單元作為共聚成分。於具有可交聯之官能基之情形時，藉由丙烯酸系聚合物之熱交聯、光硬化等，能夠使丙烯酸系黏著劑具有較高之凝集力。作為具有可交聯之官能基之丙烯酸系單體，可列舉含羥基單體、含羧基單體。其中，較佳為含有含羥基單體作為丙烯酸系聚合物之共聚成分。於丙烯酸系聚合物具有含羥基單體作為單體單元之情形時，有提高丙烯酸系聚合物之交聯性並且抑制高溫高濕環境下之黏著劑之白濁之傾向，可獲得透明性較高之黏著劑。 作為含羥基單體，可列舉：(甲基)丙烯酸2-羥基乙酯、(甲基)丙烯酸2-羥基丙酯、(甲基)丙烯酸4-羥基丁酯、(甲基)丙烯酸6-羥基己酯、(甲基)丙烯酸8-羥基辛酯、(甲基)丙烯酸10-羥基癸酯、(甲基)丙烯酸12-羥基月桂酯或丙烯酸(4-羥基甲基環己基)甲酯等。 含羥基單體單元之含量相對於丙烯酸系聚合物之構成單體單元總量，較佳為0.01重量%~20重量%，更佳為0.1重量%~15重量%，進而較佳為0.5重量%~10重量%。若含羥基單體單元之含量超過上述範圍，則存在第二黏著劑層之凝集力過度上升，階差吸收性降低之情況。 丙烯酸系聚合物較佳為除含羥基單體單元以外還含有含氮單體等極性較高之單體單元。藉由除含羥基單體單元以外還含有含氮單體單元等極性較高之單體單元，能夠兼顧高接著力及抑制高溫高濕環境下之白濁。 作為含氮單體，可列舉：N-乙烯基吡咯啶酮、甲基乙烯基吡咯啶酮、乙烯基吡啶、乙烯基哌啶酮、乙烯基嘧啶、乙烯基哌𠯤、乙烯基吡𠯤、乙烯基吡咯、乙烯基咪唑、乙烯基㗁唑、乙烯基嗎啉、(甲基)丙烯醯嗎啉、N-乙烯基羧醯胺類、N-乙烯基己內醯胺等乙烯基系單體；丙烯腈、甲基丙烯腈等氰基丙烯酸酯系單體等。其中，較佳為使用N-乙烯基吡咯啶酮及(甲基)丙烯醯嗎啉。含氮單體單元之含量相對於丙烯酸系聚合物之構成單體單元總量，較佳為3重量%~45重量%，更佳為5重量%~40重量%，進而較佳為7重量%~30重量%。 關於第二黏著劑層之丙烯酸系聚合物，相對於構成單體單元總量之含羥基單體單元之含量與含氮單體單元之含量之合計較佳為3重量%~50重量%，更佳為5重量%~40重量%，進而較佳為7重量%~30重量。若含羥基單體單元之含量與含氮單體單元之含量之合計為上述範圍，則容易形成具有適度之凝集性及加熱時之柔軟性之丙烯酸系黏著劑層。 用於形成丙烯酸系聚合物之單體成分中亦可含有多官能單體成分。藉由含有多官能單體作為共聚單體成分，有常溫下之儲存模數提高之傾向。多官能單體係具有至少兩個聚合性官能基(例如乙烯基)之單體。多官能性單體之使用量根據其分子量或官能基數等而不同，相對於形成(甲基)丙烯酸系聚合物之全部單體成分，較佳為5重量%以下，更佳為3重量%以下，進而較佳為1重量%以下。若多官能性單體之使用量超過5重量%，則存在黏著劑之柔軟性降低，產生階差附近之氣泡或顯示不均。 丙烯酸系聚合物可藉由溶液聚合、UV聚合、塊狀聚合、乳化聚合等公知之聚合方法製備。就黏著劑之透明性、耐水性、成本等方面而言，較佳為溶液聚合法或活性能量線聚合法(例如UV聚合)。作為溶液聚合之溶劑，通常使用乙酸乙酯、甲苯等。 於丙烯酸系聚合物之製備時，可根據聚合反應之種類使用光聚合起始劑或熱聚合起始劑等聚合起始劑。作為光聚合起始劑，只要使光聚合開始者則並無特別限制，例如可使用安息香醚系光聚合起始劑、苯乙酮系光聚合起始劑、α-酮醇系光聚合起始劑、芳香族磺醯氯系光聚合起始劑、光活性肟系光聚合起始劑、安息香系光聚合起始劑、苯偶醯系光聚合起始劑、二苯甲酮系光聚合起始劑、縮酮系光聚合起始劑、9-氧硫

Figure 106139847-A0304-xxxx-3
系光聚合起始劑、醯基氧化膦系光聚合起始劑等。作為熱聚合起始劑，例如可使用偶氮系起始劑、過氧化物系起始劑、將過氧化物與還原劑組合而獲得之氧化還原系起始劑(例如，過硫酸鹽與亞硫酸氫鈉之組合、過氧化物與抗壞血酸鈉之組合等)。 為了調整丙烯酸系聚合物之分子量，亦可使用鏈轉移劑。鏈轉移劑能夠自生長之聚合物鏈接收自由基而使聚合物停止伸長，並且接收有自由基之鏈轉移劑能夠攻擊單體而再次使聚合開始。因此，藉由使用鏈轉移劑，可於不使反應系中之自由基濃度降低之情況下抑制丙烯酸系聚合物之分子量之增大，從而可獲得具有適度柔軟性之黏著劑。作為鏈轉移劑，例如可較佳地使用α-硫甘油、月桂基硫醇、縮水甘油基硫醇、巰基乙酸、2-巰基乙醇、硫代乙醇酸、硫代乙醇酸2-乙基己酯、2,3-二巰基-1-丙醇等硫醇類。 於除單官能單體以外還使用多官能單體作為形成丙烯酸系聚合物之單體成分之情形時，可先使單官能單體聚合，形成低聚合度之預聚物組合物(預聚合)，並在預聚物組合物(預聚合漿)中添加多官能單體，將預聚物與多官能單體進行聚合(後聚合)。藉由如此進行預聚物之預聚合，能夠於丙烯酸系聚合物中均勻地導入起因於多官能單體成分之分支點。又，亦可將預聚物組合物與未聚合之單體成分之混合物(黏著劑組合物)塗佈於基材上，然後於基材上進行後聚合而形成黏著片。預聚物組合物由於為低黏度且塗佈性優異，故而根據將作為預聚物組合物與未聚合單體之混合物的黏著劑組合物塗佈後在基材上進行後聚合之方法，能夠提高黏著片之生產性，並且可使黏著片之厚度均勻。 預聚物組合物例如可藉由使構成丙烯酸系聚合物之單體成分(稱為「單體成分A」)與聚合起始劑混合而獲得之組合物(稱為「預聚物形成用組合物」)進行部分聚合(預聚合)而製備。再者，預聚物形成用組合物中之上述單體成分A較佳為構成丙烯酸系聚合物之單體成分中之(甲基)丙烯酸烷基酯或含極性基單體等單官能單體成分。單體成分A不僅可含有單官能單體，亦可含有多官能單體。例如，可於預聚物形成用組合物中含有成為丙烯酸系聚合物之原料之多官能單體成分之一部分，使預聚物進行聚合後，添加多官能單體成分之剩餘部分而供於後聚合。 預聚物形成用組合物中除單體成分A及聚合起始劑以外，亦可視需要含有鏈轉移劑等。預聚物形成用組合物之聚合方法並無特別限定，就藉由調整反應時間而將預聚物之分子量(聚合率)設為所需範圍之觀點而言，較佳為藉由UV光等活性光線照射進行之聚合。預聚合中使用之聚合起始劑或鏈轉移劑並無特別限定，例如可使用上述光聚合起始劑、鏈轉移劑。 預聚物之聚合率並無特別限定，就設為適合於基材上之塗佈之黏度之觀點而言，較佳為3重量%~50重量%，更佳為5重量%~40重量%。預聚物之聚合率可藉由調整光聚合起始劑之種類或使用量、UV光等活性光線之照射強度、照射時間等而調整為所需之範圍。再者，預聚物之聚合率由將預聚物組合物係根據在130℃下加熱3小時之時之加熱(乾燥)前後之重量並藉由下述式而算出。於藉由溶液聚合進行預聚合之情形時，將自預聚物組合物之總重量中減去溶劑之量而獲得之重量作為下述式中之乾燥前重量而算出聚合率。 預聚物組合物之聚合率(%)＝乾燥後之重量/乾燥前之重量×100 於上述預聚物組合物中混合構成丙烯酸系聚合物之單體成分(稱為「單體成分B」)並視需要混合聚合起始劑、鏈轉移劑、矽烷偶合劑、交聯劑等，從而形成黏著劑組合物。單體成分B較佳為含有多官能單體。單體成分B除多官能單體以外亦可含有單官能單體。 後聚合中使用之光聚合起始劑或鏈轉移劑並無特別限定，例如可使用上述光聚合起始劑或鏈轉移劑。於預聚合時之聚合起始劑在預聚物組合物中不失活而殘留之情形時，可省略添加用於後聚合之聚合起始劑。 丙烯酸系聚合物亦可視需要具有交聯結構。交聯結構之形成例如係藉由於預聚合後或基礎聚合物之聚合後添加交聯劑而進行。作為交聯劑，可使用異氰酸酯系交聯劑、環氧系交聯劑、㗁唑啉系交聯劑、氮丙啶系交聯劑、碳二亞胺系交聯劑、金屬螯合物系交聯劑等通常使用者。 交聯劑之含量相對於基礎聚合物100重量份，通常為0~5重量份之範圍，較佳為0~3重量份。若交聯劑之含量過多，則黏著劑之柔軟性降低，容易產生階差附近之氣泡或顯示不均。 於黏著劑組合物中含有交聯劑之情形時，較佳為在與被黏著體貼合前藉由加熱進行交聯處理而形成交聯結構。交聯處理中之加熱溫度或加熱時間根據所使用之交聯劑之種類而適當設定，通常於20℃~160℃之範圍內藉由1分鐘至7天左右之加熱進行交聯。 第二黏著劑層22可為光硬化型或熱硬化型黏著劑。藉由使用光硬化型或熱硬化型黏著劑作為第二黏著劑層22，經由正面側黏著片20將偏光板10與正面透明構件70貼合後，使第二黏著劑層22硬化，能夠增大黏著劑層之儲存模數。因此，即使於圖像顯示裝置暴露於高溫環境之情形時亦可抑制黏著劑之流動，能夠實現不易發生氣泡之產生或剝離之具有長期可靠性之接著性。尤其是就與正面透明構件貼合後容易硬化之方面而言，較佳為光硬化型黏著劑。 光硬化型黏著劑除基礎聚合物以外亦含有光硬化性成分。作為光硬化性成分，較佳為使用具有碳-碳雙鍵(C=C鍵)之自由基聚合性化合物(乙烯性不飽和化合物)。自由基聚合性化合物可以單體或低聚物之形式存在於黏著劑組合物中，亦可與基礎聚合物之羥基等官能基鍵結。硬化型黏著劑較佳為含有聚合起始劑(光聚合起始劑或熱聚合起始劑)。 於自由基聚合性化合物以單體或低聚物之形式存在於黏著劑組合物中之情形時，較佳為使用一分子中具有兩個以上聚合性官能基之多官能聚合性化合物。作為多官能聚合性化合物，可列舉一分子中具有兩個以上C=C鍵之化合物、一分子中具有一個C=C鍵及環氧基、氮丙啶、㗁唑啉、肼、羥甲基等聚合性官能基之化合物等。其中，較佳為如多官能丙烯酸酯般一分子中具有兩個以上C=C鍵之多官能聚合性化合物。 藉由將具有能夠與基礎聚合物之官能基鍵結之官能基及自由基聚合性官能基之自由基聚合性化合物與基礎聚合物進行混合，可於基礎聚合物中導入自由基聚合性官能基，並將黏著劑組合物製成硬化型黏著劑。作為能夠與基礎聚合物之官能基鍵結之官能基，較佳為異氰酸基。異氰酸基與基礎聚合物之羥基形成胺基甲酸酯鍵，因此能夠容易地進行向基礎聚合物中導入自由基聚合性官能基。 作為光硬化之方法，較佳為對含有光硬化性化合物及光聚合起始劑之系統照射紫外線等活性光線之方法。尤其是就高光感度、可選擇之材料豐富之方面而言，較佳為使用了乙烯性不飽和化合物及光自由基發生劑之系統。於第二黏著劑層22為光硬化型黏著劑之情形時，光硬化性化合物之含量相對於黏著劑組合物整體100重量份，較佳為2~50重量份，更佳為5~30重量份。 ＜黏著劑組合物中之添加劑＞ 用以形成第一黏著劑層21之黏著劑組合物及用以形成第二黏著劑層22之黏著劑組合物除基礎聚合物以外亦可含有各種添加劑。例如，為了調整接著力，亦可於黏著劑組合物中添加矽烷偶合劑。矽烷偶合劑可單獨使用一種，或者亦可併用兩種以上。尤其是於第二黏著劑層以丙烯酸系聚合物作為主成分之情形時，用以形成第二黏著劑層之黏著劑組合物較佳為含有矽烷偶合劑。矽烷偶合劑之添加量相對於丙烯酸系聚合物100重量份，通常為0.01~5重量份左右，較佳為0.03~2重量份左右。 黏著劑組合物中亦可視需要添加黏著賦予劑。尤其是於第一黏著劑層21為含有橡膠系聚合物作為主成分之黏著劑層之情形時，就提高與偏光元件11之接著性之觀點而言，較佳為於黏著劑組合物中含有黏著賦予劑。作為黏著賦予劑，例如可使用萜烯系黏著賦予劑、苯乙烯系黏著賦予劑、酚系黏著賦予劑、松香系黏著賦予劑、環氧系黏著賦予劑、二聚環戊二烯系黏著賦予劑、聚醯胺系黏著賦予劑、酮系黏著賦予劑、彈性體系黏著賦予劑等。尤其是作為第一黏著劑層中使用之黏著賦予劑，就與橡膠系材料之相容性及透明性優異之方面而言，較佳為萜烯系黏著賦予劑。 作為萜烯系黏著賦予劑，例如可列舉：α-蒎烯聚合物、β-蒎烯聚合物、雙戊烯聚合物等萜烯聚合物或萜酚樹脂、苯乙烯改性萜烯樹脂、芳香族改性萜烯樹脂、氫化萜烯樹脂(hydrogenated terpene resin)等改性萜烯樹脂。 第一黏著劑層21中含有之黏著賦予劑較佳為軟化點為70℃~200℃左右，更佳為100℃~180℃左右。軟化點為藉由JIS K2207「環球式軟化點試驗方法」所得之測定值。 第一黏著劑層21中之黏著賦予劑之含量相對於橡膠系基礎聚合物100重量份，較佳為100重量份以下，更佳為80重量份以下，進而較佳為50重量份以下。黏著賦予劑之含量之下限值並無特別限定，為了獲得提高與偏光元件之接著性之效果，較佳為1重量份以上，更佳為5重量份以上。 第二黏著劑層亦可含有黏著賦予劑。黏著賦予劑於第二黏著劑層中之使用能夠有助於調整儲存模數之溫度依存性。就對第二黏著劑層22之儲存模數賦予所需之溫度依存性之觀點而言，第二黏著劑層中含有之黏著賦予劑較佳為軟化點為50℃~150℃左右，更佳為70℃~140℃左右。 第一黏著劑層21及第二黏著劑層22較佳為至少任一者含有紫外線吸收劑。通常，設置於偏光元件之表面之透明保護膜為了防止因紫外線引起之偏光元件之劣化而含有紫外線吸收劑。另一方面，由於單面保護偏光板10於正面側黏著片20之附設面未設置透明保護膜，故而較佳為使第一黏著劑層21及/或第二黏著劑層22具有紫外線吸收性，從而防止因紫外線引起之偏光元件11之劣化。 作為紫外線吸收劑，例如可列舉：二苯甲酮系紫外線吸收劑、苯并三唑系紫外線吸收劑、水楊酸系紫外線吸收劑、草醯苯胺系紫外線吸收劑、氰基丙烯酸酯系紫外線吸收劑、三𠯤系紫外線吸收劑等。紫外線吸收劑之含量相對於黏著劑之基礎聚合物100重量份，較佳為0.01~15重量份，更佳為0.1~10重量份。正面側黏著片20較佳為波長380 nm下之透光率為15%以下，更佳為10%以下。 除了上述例示之各成分以外，亦可於無損黏著劑之特性之範圍內向黏著劑組合物中添加塑化劑、軟化劑、劣化防止劑、填充劑、著色劑、抗氧化劑、界面活性劑、防靜電劑等添加劑。 用於形成第一黏著劑層21之黏著劑組合物較佳為橡膠系聚合物之含量為40重量%以上，更佳為50重量%以上，進而較佳為60重量%以上。用於形成第二黏著劑層22之黏著劑組合物較佳為丙烯酸系聚合物之含量為40重量%以上，更佳為50重量%以上，進而較佳為60重量%以上。 ＜黏著劑層之形成＞ 作為黏著劑層之形成方法，可使用各種方法。具體而言，例如可列舉：輥塗、接觸輥式塗佈、凹版塗佈、反向塗佈、輥刷、噴塗、浸漬輥塗佈、棒式塗佈、刮刀塗佈、氣刀塗佈、淋幕式塗佈、模唇塗佈、利用模嘴塗佈機等之擠出塗佈法等方法。該等之中，較佳為使用模嘴塗佈機，尤其更佳為使用利用噴注式模嘴、狹縫式模嘴之模嘴塗佈機。 於黏著劑組合物之基礎聚合物為溶液聚合聚合物之情形時，較佳為於塗佈後進行溶劑之乾燥。作為乾燥方法，可根據目的適當採用適合之方法。加熱乾燥溫度較佳為40℃~200℃，進而較佳為50℃~180℃，尤佳為70℃~170℃。乾燥時間可適當採用適合之時間。乾燥時間較佳為5秒~20分鐘，進而較佳為5秒~15分鐘，尤佳為10秒~10分鐘。 於黏著劑組合物含有交聯劑之情形時，可於塗佈至基材後藉由加熱進行交聯。加熱溫度及加熱時間可根據所使用之交聯劑之種類而適當設定，通常於20℃~160℃之範圍內藉由1分鐘至7天左右之加熱進行交聯。用以使塗佈後之黏著劑乾燥之加熱亦可兼作用於交聯之加熱。 第一黏著劑層與第二黏著劑層之積層方法並無特別限定。可於將第一黏著劑層及第二黏著劑層之各者個別地形成為黏著片後將兩者重疊，亦可先將一黏著劑層形成為黏著片後在其上塗佈另一黏著劑層而獲得積層黏著片。又，亦可藉由第一黏著劑層形成用組合物與第二黏著劑層形成用組合物之共擠出而形成積層黏著片。 正面側黏著片20可為包含第一黏著劑層21及第二黏著劑層22之兩層之積層黏著片，亦可於第一黏著劑層與第二黏著劑層之間及/或於第二黏著劑層22上具有其他黏著劑層。就黏著片之生產性及薄型化之觀點而言，正面側黏著片20較佳為包含第一黏著劑層21與第二黏著劑層22之兩層。 ＜黏著片之特性＞ 與單面保護偏光板10之偏光元件11相接而配置之第一黏著劑層21係由低透濕度之黏著劑構成，與偏光元件11間隔而配置之第二黏著劑層22係由高溫下之儲存模數較小且柔軟之黏著劑構成。藉由與偏光元件11相接而設置低透濕之第一黏著劑層21，即使於第二黏著劑層22之透濕度較高之情形時，亦可藉由第一黏著劑層21阻斷水分向偏光元件11之轉移，因此能夠抑制因水分自正面側黏著片20之側面之轉移所引起之偏光元件之劣化。 另一方面，包含橡膠系聚合物等之低透濕之黏著劑由於通常玻璃轉移溫度較低，故而常溫(25℃)及加熱時(80℃)之黏著劑之儲存模數之溫度依存性較小，80℃下之儲存模數G'80 與25℃下之儲存模數G'25 之比G'25 /G'80 通常為3以下。即使於以橡膠系聚合物作為主成分之第一黏著劑層21中使用黏著賦予劑，亦難以增大G'25 /G'80 。於藉由使第一黏著劑層中含有大量之黏著賦予劑或塑化劑來減小G'80 而具有階差吸收性之情形時，常溫(25℃)下之儲存模數G'25 亦降低，因此容易發生黏著劑自端面之溢出或向切割刀等之轉移。 藉由於低透濕之第一黏著劑層21上積層柔軟之黏著劑作為第二黏著劑層22，黏著劑可進入正面透明構件之印刷階差附近，因此能夠抑制階差附近之氣泡混入。進而，可維持正面側黏著片20整體之柔軟性，因此可抑制由印刷階差引起之畫面周緣部之顯示不均。 如上所述，第二黏著劑層22較佳為80℃下之儲存模數G'80 與25℃下之儲存模數G'25 之比G'25 /G'80 為3.5以上，更佳為5以上，進而較佳為7以上。第二黏著劑層22之G'25 /G'80 較佳為大於第一黏著劑層21之G'25 /G'80 。第二黏著劑層22之G'25 /G'80 較佳為第一黏著劑層21之G'25 /G'80 之2倍以上，更佳為3倍以上，進而較佳為4倍以上。第一黏著劑層與第二黏著劑層之G'25 /G'80 之比係表示該等黏著劑層之儲存模數之溫度依存性之差異的指標，該比率越大，表示黏彈性行為之差異越大。 第二黏著劑層22之厚度d2 較佳為大於第一黏著劑層21之厚度d1 。第一黏著劑層21之厚度d1 與第二黏著劑層22之厚度d2 之比d2 /d1 較佳為1.5~15，更佳為2~10，進而較佳為2.5~8。藉由使第二黏著劑層之厚度相對大於第一黏著劑層，在第一黏著劑層21與第二黏著劑層22積層而獲得之正面側黏著片20整體之黏彈性行為中，第二黏著劑層之黏彈性占支配地位。因此，正面側黏著片20之階差吸收性提高，能夠抑制對於印刷階差附近之氣泡混入或圖像顯示裝置之顯示不均。 就加熱時之流動性較高、且抑制黏著劑自端面溢出之觀點而言，正面側黏著片20之80℃下之儲存模數G'80 較佳為1×103 Pa~1.5×105 Pa，更佳為3×103 Pa~1×105 Pa，進而較佳為5×103 Pa~7×104 Pa。就防止黏著劑自端面溢出或將附黏著劑之偏光板切割成特定尺寸時之黏著劑向切割刀等之轉移、並且抑制黏著劑之破裂或缺損之觀點而言，正面側黏著片20之25℃下之儲存模數G'25 較佳為1×104 Pa~1×107 Pa，更佳為4×104 Pa~6×106 Pa，進而較佳為6×104 Pa~1×106 Pa。 正面側黏著片20之80℃下之儲存模數G'80 與25℃下之儲存模數G'25 之比G'25 /G'80 較佳為2~100，更佳為5~50，進而較佳為7~30。如上所述，藉由使第二黏著劑層22之厚度相對大於第一黏著劑層21，在正面側黏著片20整體之黏彈性行為中，第二黏著劑層之黏彈性占支配地位，因此，可增大正面側黏著片20之儲存模數之溫度依存性，能夠將G'25 /G'80 之值調整為上述範圍內。 於構成正面側黏著片20之第一黏著劑層及/或第二黏著劑層包含光硬化型或熱硬化型黏著劑之情形時，如上所述較佳為硬化前之黏著片之儲存模數為上述範圍。另一方面，正面側黏著片之透濕度與將正面透明板和偏光元件貼合後之圖像顯示裝置之加濕耐久性相關，因此較佳為硬化後(圖像顯示裝置形成後)之值如上所述為150 g/m2 ･24 h以下。 [附黏著劑之偏光板之形成] 於單面保護偏光板10上附設正面側黏著片20之方法並無特別限定。可預先形成將第一黏著劑層21與第二黏著劑層積層而得之積層黏著片，並將積層黏著片之第一黏著劑層21貼合於偏光元件11上；亦可於偏光元件11上依序貼合第一黏著劑層21及第二黏著劑層22。亦可於偏光元件11上塗佈第一黏著劑層形成用組合物而形成第一黏著劑層21，並在其上藉由塗佈或轉印而形成第二黏著劑層22。又，亦可藉由第一黏著劑層形成用組合物與第二黏著劑層形成用組合物之共擠出而於偏光元件11上形成積層黏著片，從而獲得附黏著劑之偏光板。 如圖1所示，較佳為於附黏著劑之偏光板1之正面側黏著片20上以可剝離之方式貼合保護片41。保護片係出於在將黏著劑用於與被黏著體貼合之前之期間對黏著劑之露出面進行保護之目的而使用。亦可將黏著劑層之形成(塗佈)時使用之基材直接用作正面側黏著片上之保護片41。 作為保護片41之構成材料，較佳為使用聚乙烯、聚丙烯、聚對苯二甲酸乙二酯、聚酯膜等塑膠膜。保護片之厚度通常為5~200 μm左右，較佳為10~150 μm左右。保護片亦可視需要藉由矽酮系、氟系、長鏈烷基系或脂肪酸醯胺系之脫模劑、二氧化矽粉等進行脫模及防污處理、或者進行塗佈型、混練型、蒸鍍型等之防靜電處理。尤其是藉由對保護片之表面適當進行矽酮處理、長鏈烷基處理、氟處理等剝離處理，能夠進一步提高自黏著劑之剝離性。 [雙面附黏著劑之偏光板] 藉由以與單面保護偏光板10之偏光元件11相接之方式設置正面側黏著片20，並在透明保護膜15之附設面上設置另一黏著片(單元側黏著片)30，藉此獲得如圖3所示之雙面附黏著劑之偏光板。於圖3所示之狀態下，在雙面附黏著劑之偏光板2之正面側黏著片20上以可剝離之方式貼合有保護片41，在單元側黏著片30上以可剝離之方式貼合有保護片42。 若使用如此於偏光板10之兩面預先附設有黏著劑層之雙面附黏著劑之偏光板，則在將偏光板貼合於圖像顯示單元之表面後，可省略在偏光板上附設另外之黏著片之步驟，能夠簡化圖像顯示裝置之製造步驟。 ＜單元側黏著片＞ 單元側黏著片30之厚度較佳為3 μm~30 μm，更佳為5 μm~27 μm，進而較佳為10 μm~25 μm。作為單元側黏著片，可使用用於偏光板與圖像顯示單元之貼合之各種黏著劑。作為構成單元側黏著片之黏著劑，較佳為使用丙烯酸系黏著劑。 單元側黏著片30較佳為20℃下之儲存模數G'25 為1×104 Pa~1×107 Pa，更佳為5×104 Pa~5.0×106 Pa，進而較佳為1×105 Pa~1×106 Pa。若單元側黏著片之G'25 為上述範圍，則能夠顯示出適度之接著性並且抑制切割時黏著劑向切割刀等之轉移或黏著劑之破裂、缺損等。 [圖像顯示裝置] 圖2係表示圖像顯示裝置之一形態之模式性剖視圖。本發明之附黏著劑之偏光板適合用於形成如下圖像顯示裝置100，該圖像顯示裝置100於單面保護偏光板10之偏光元件11側之主面(視認側)具備觸控面板或正面透明板等正面透明構件70，且於透明保護膜15側之主面具備液晶單元或有機EL單元等圖像顯示單元60。該圖像顯示裝置100中，正面側黏著片20用於單面保護偏光板10之偏光元件11與正面透明構件70之貼合。 作為正面透明構件70，可列舉正面透明板(視窗層)或觸控面板等。作為正面透明板，可使用具有適當之機械強度及厚度之透明板。作為此種透明板，例如可使用丙烯酸系樹脂或聚碳酸酯系樹脂等透明樹脂板、或者玻璃板等。作為觸控面板，可使用電阻膜式、靜電電容式、光學式、超音波式等任意方式之觸控面板。 於使用圖3所示之雙面附黏著劑之偏光板之情形時，圖像顯示單元60與附黏著劑之偏光板2之貼合方法、及正面透明構件70與附黏著劑之偏光板2之貼合方法並無特別限定，可於將貼合於正面側黏著片20及單元側黏著片30各自之表面之保護片41、42剝離後，藉由各種公知之方法進行貼合。 就提高貼合之作業性或偏光板之軸精度之觀點而言，較佳為將保護片42自單元側黏著片30之表面剝離後，進行經由黏著片30將偏光板10與圖像顯示單元60貼合之單元側貼合步驟，其後，將保護片41自正面側黏著片20之表面剝離，進行經由正面側黏著片20將偏光板10與正面透明構件70貼合之正面側貼合步驟。 將正面透明構件70貼合於正面側黏著片20後，較佳為進行用於將正面側黏著片20與正面透明構件70之界面或正面透明構件70之印刷部76等非平坦部附近之氣泡去除之脫泡。作為脫泡方法，可採用加熱、加壓、減壓等適當之方法。例如，較佳為於減壓、加熱下抑制氣泡混入之同時進行貼合，其後，以抑制延遲起泡等為目的，藉由高壓釜處理等在加熱之同時進行加壓。 於正面側黏著片20包含光硬化型或熱硬化型黏著劑之情形時，較佳為於偏光板10與正面透明構件70之貼合後進行硬化。藉由將黏著劑層硬化，可提高偏光板10與正面透明構件70之接著可靠性。黏著劑層之硬化方法並無特別限定。於進行光硬化之情形時，較佳為透過正面透明構件70照射紫外線等活性光線之方法。 [實施例] 以下，列舉實施例及比較例，更詳細地對本發明進行說明，但本發明不限於該等實施例。 [黏著劑及黏著片之物性之評價方法] ＜儲存模數＞ 將複數個黏著片積層而獲得厚度為約1.5 mm之黏著片，將其作為測定用試樣。再者，積層黏著片之儲存模數之測定中使用將第一黏著劑層與第二黏著劑層交替積層而獲得之厚度約1.5 mm者作為測定用試樣。關於光硬化型黏著片M1，將硬化前後之各黏著片作為測定用試樣。使用Rheometric Scientific製造之「Advanced Rheometric Expansion System(ARES)」，藉由以下之條件進行動態黏彈性測定，由測定結果讀取25℃及80℃下之儲存模數(G'25 、G'80 )。 (測定條件) 變形模式：扭轉 測定頻率：1 Hz 升溫速度：5℃/分鐘 測定溫度：-50℃~150℃之範圍 形狀：平行板 8.0 mm
Figure 02_image001
＜透濕度＞ 剝離黏著片之一面之隔離膜，於露出面貼合厚度25 μm之三乙醯纖維素膜(透濕度：1070 g/m2 ･24 h)，然後剝離另一面之隔離膜，根據JIS Z0208之透濕度試驗(杯式法)在溫度40℃、相對濕度92%之恆溫恆濕槽中進行24 h之透濕試驗，並算出透濕度。對於光硬化型黏著片M1及使用黏著片M1之實施例3之積層黏著片，在將黏著片貼合於三乙醯纖維素膜並進行UV硬化後，實施透濕試驗。藉由該測定求出之透濕度為三乙醯纖維素膜與黏著片之積層體之透濕度，但由於三乙醯纖維素膜之透濕度充分大於黏著片之透濕度，故而可認為積層體之透濕度＝黏著片之透濕度。 ＜紫外線透過率＞ 利用紫外可見分光光度計測定黏著片之透過率光譜，讀取波長380 nm下之透過率。 [橡膠系黏著片之製作] ＜黏著片A1~A5之製作＞ 將聚異丁烯(PIB；BASF製造之「OPPANOL B80」、重量平均分子量：約75萬、玻璃轉移溫度：-63℃)100重量份及苯并三唑系紫外線吸收劑(BASF製造之「TINUVIN 384-2」)7.8重量份與300重量份之甲苯進行混合，從而製備黏著劑組合物A。將上述黏著劑組合物A以成為表1所示之乾燥後厚度之方式塗佈於隔離膜(單面利用矽酮進行過剝離處理之聚酯膜)之剝離處理面，然後於130℃下加熱2分鐘而去除溶劑，從而製作黏著片。 ＜黏著片B1之製作＞ 使用未添加紫外線吸收劑之黏著劑組合物B，以與上述同樣之方式製作黏著片B1。 ＜黏著片C1及C2之製作＞ 將聚苯乙烯-聚(乙烯/丙烯)-聚苯乙烯嵌段共聚物(可樂麗製造之「SEPTON 2063」、苯乙烯含量：13%；SEPS)100重量份及三𠯤系紫外線吸收劑(BASF製造之「TINOSORB S」)8.9重量份與300重量份之甲苯進行混合，從而製備黏著劑組合物C。將上述黏著劑組合物C以成為表1所示之乾燥後厚度之方式塗佈於隔離膜之剝離處理面，然後於130℃下加熱2分鐘而去除溶劑，從而製作黏著片。 將上述黏著劑組合物A~C之組成以及各黏著片之特性(厚度、透濕度及儲存模數)示於表1。 [表1]
Figure 106139847-A0304-0001
 [丙烯酸系黏著片之製作] ＜黏著片K1~K3之製作＞ (黏著劑組合物之製備) 向反應容器內投入丙烯酸2-乙基己酯(2EHA)40重量份、丙烯酸異硬脂酯(ISA)40重量份、N-乙烯基吡咯啶酮(NVP)19重量份、丙烯酸4-羥基丁酯(4HBA)1重量份及作為光聚合起始劑之1-羥基環己基苯基酮(BASF製造之「IRGACURE184」)0.1重量份，於氮氣環境下照射紫外線，而獲得聚合率10%之預聚物組合物。向該預聚物組合物100重量份中以表2所示之調配量添加作為光聚合起始劑之2,2-二甲氧基-1,2-二苯基乙烷-1-酮(BASF製造之「IRGACURE651」；IRG651)、作為多官能單體之三羥甲基丙烷三丙烯酸酯(TMPTA)、作為鏈轉移劑之α-硫甘油(TGR)及作為矽烷偶合劑之3-縮水甘油氧基丙基三甲氧基矽烷(信越化學製造之「KBM403」)，然後將該等均勻地混合，而製備黏著劑組合物K。 (黏著片之製作) 將上述黏著劑組合物K以成為表2所示之厚度之方式塗佈於隔離膜之剝離處理面，而形成塗佈層，於塗佈層上貼合另一隔離膜之剝離處理面。然後，利用以使燈正下方之照射面之照射強度成為5 mW/cm2 之方式經位置調節之黑光燈進行UV照射，直至累計光量達到3000 mJ/cm2 ，使聚合進行，從而製作丙烯酸系黏著片。 ＜黏著片L1及L2＞ 相對於預聚物組合物100重量份，向黏著劑組合物K中添加0.7重量份之三𠯤系紫外線吸收劑(BASF製造之「TINOSORB S」)，而製備黏著劑組合物L。使用該黏著劑組合物L，與上述同樣地進行塗佈及UV聚合，製作厚度100 μm之黏著片L1及厚度125 μm之黏著片L2。 ＜黏著片M1＞ 將72重量份2EHA、13重量份NVP、14重量份丙烯酸2-羥基乙酯(2HEA)、0.2重量份之作為熱聚合起始劑之偶氮二異丁腈(AIBN)及0.12重量份之作為鏈轉移劑之TGR與150重量份乙酸乙酯一併投入反應容器內，於23℃之氮氣環境下攪拌1小時，進行氮氣置換。其後，於65℃下反應7小時，而獲得重量平均分子量(Mw)為25萬之丙烯酸系基礎聚合物之溶液。向該丙烯酸系基礎聚合物溶液中以表2所示之調配量添加作為異氰酸酯系交聯劑之苯二亞甲基二異氰酸酯之三羥甲基丙烷加成物(三井化學製造之「TAKENATE D110N」)、作為光聚合性多官能單體之聚丙二醇二丙烯酸酯(新中村工業化學製造之「NK ESTER APG400」)、作為光聚合起始劑之IRGACURE651及作為矽烷偶合劑之KBM403，然後均勻地混合，而製備黏著劑組合物溶液。將上述黏著劑組合物以乾燥後之厚度成為100 μm之方式塗佈於隔離膜之剝離處理面，於100℃下加熱6分鐘，乾燥去除溶劑並且使異氰酸酯交聯劑進行熱交聯，從而獲得光硬化型黏著片M1。 ＜黏著片N1及O1＞ 如表2所示般變更預聚物之添加單體組成、以及多官能單體及紫外線吸收劑之添加量，除此以外，以與上述黏著劑組合物K同樣之方式製備黏著劑組合物N及O。使用該等黏著劑組合物，以與上述同樣之方式製作厚度125 μm之黏著片N1及O1。 將上述黏著劑組合物K~O之組成以及各黏著片之特性(厚度、透濕度及儲存模數)示於表2。 [表2]
Figure 106139847-A0304-0002
 [單元側黏著片之製作] (黏著劑組合物之製備) 將作為單體成分之丙烯酸丁酯97重量份及丙烯酸3重量份、以及作為熱聚合起始劑之偶氮二異丁腈(AIBN)0.2重量份與乙酸乙酯233重量份一併投入反應容器內，於23℃之氮氣環境下攪拌1小時，進行氮氣置換。其後，於60℃下反應5小時，而獲得重量平均分子量(Mw)為110萬之丙烯酸系基礎聚合物之溶液。向該丙烯酸系基礎聚合物溶液中添加作為異氰酸酯系交聯劑之三羥甲基丙烷甲苯二異氰酸酯(Nippon Polyurethane Industry製造之「CORONATE L」)0.8重量份及矽烷偶合劑(信越化學製造之「KBM403」)0.1重量份，然後均勻地混合，而製備黏著劑組合物溶液。 (黏著片之製作) 將上述黏著劑組合物以乾燥後之厚度成為20 μm之方式塗佈於隔離膜之剝離處理面，於100℃下乾燥3分鐘而去除溶劑，從而獲得黏著片。其後，於50℃下加熱48小時，進行交聯處理，而獲得單元側黏著片。 [單面保護偏光板之製作] 於包含厚度25 μm之含浸有碘之延伸聚乙烯醇膜之偏光元件之一面(單元側之面)，經由接著劑貼合聚環烯烴保護膜，從而製作單面保護偏光板。 [實施例1] 使用輥式層壓機於單面保護偏光板之偏光元件之露出面貼合有上述黏著片A1。進而，使用輥式層壓機於黏著片A1上貼合有上述黏著片K1。其後，使用輥式層壓機於單面保護偏光板之聚環烯烴保護膜上貼合有上述單元側黏著片。如此獲得雙面附黏著劑之偏光板，其於單面保護偏光板之偏光元件露出面側具備包含黏著片A1與黏著片K1之積層黏著片之正面側黏著片，且於單面保護偏光板之透明保護膜附設面具備單元側黏著片。 [實施例2~7、比較例1~3] 如表3所示般變更貼合於單面保護偏光板之偏光元件露出面之正面側黏著片之構成，除此以外，以與上述實施例1同樣之方式獲得雙面附黏著劑之偏光板。 [比較例4、5] 將貼合於單面保護偏光板之視認側之面之黏著片分別變更為黏著片A5、包含L2單層之厚度125 μm之黏著片，除此以外，以與上述實施例1同樣之方式獲得雙面附黏著劑之偏光板。 [評價] ＜顯示不均＞ 自任天堂3DS之更換用上部液晶面板卸除背光源部分，並卸除與液晶面板之背光源為相反側之偏光板，其後使用浸入有乙醇之潔淨之布去除液晶單元表面之黏著劑。將雙面附黏著劑之偏光板切割成50 mm×80 mm之尺寸，然後剝離單元側表面之隔離膜，將單元側黏著片表面重疊於液晶單元表面之中央部，並使用手壓輥進行貼合。 其後，剝離雙面附黏著劑之偏光板之視認側表面之隔離膜，將於周緣部以框狀印刷有黑色油墨之玻璃板(0.7 mm厚×50 mm×100 mm、油墨印刷厚度＝10 μm、兩短邊(長邊方向)之油墨印刷寬度：各15 mm、兩長邊(短邊方向)之油墨印刷寬度：各5 mm)之印刷面載置於黏著劑之露出面上，利用真空熱壓接裝置進行貼合(溫度25℃、裝置內壓力50 Pa、壓力0.3 MPa、壓力保持時間10秒)。其後，進行高壓釜處理(50℃、0.5 MPa、15分鐘)，而獲得評價用面板。對於使用光硬化型黏著片之實施例3，於高壓釜處理後，使用高壓水銀燈介隔視認側之玻璃板照射累計光量3000 mJ/cm2 之紫外線，進行黏著劑之UV硬化，將所獲得者作為評價用面板。 將評價用面板與任天堂3DS主體之圖像顯示面板更換，進行電連接，而獲得評價用圖像顯示裝置。藉由目視確認使面板進行白色顯示時在印刷框附近有無顯示不均，將未確認到顯示不均者設為○，將略微觀察到顯示不均者設為Δ，將容易地確認到顯示不均者設為×。 ＜氣泡＞ 將雙面附黏著劑之偏光板切割成45 mm×75 mm之尺寸，其後剝離單元側表面之隔離膜，使用手壓輥貼合於0.2 mm厚×50 mm×100 mm之玻璃板之中央部。然後，與上述顯示不均評價用面板之製作同樣地在雙面附黏著劑之偏光板之視認側之面貼合在周緣部以框狀印刷有黑色油墨之玻璃板，進行高壓釜處理，從而獲得評價用面板。對於實施例3，與顯示不均評價用面板同樣地在高壓釜處理後進行黏著劑之UV硬化，將所獲得者設為評價用面板。 利用倍率20倍之數位顯微鏡對評價用面板之黑色油墨印刷部之內側附近進行觀察，確認黏著片中有無氣泡(初始評價)。又，投入至85℃之烘箱中48小時，然後藉由同樣之方法確認氣泡之有無(加熱後評價)。於初始及加熱後之各評價中，將未確認到氣泡者設為〇，將確認到氣泡者設為×。 ＜加濕耐久性(端部褪色)之評價＞ 將雙面附黏著劑之偏光板切割成50 mm×50 mm之尺寸後，於兩面之黏著劑層上分別重疊無鹼玻璃板，使用手壓輥進行貼合。進而，對於實施例3，介隔貼合於第一黏著劑層側之玻璃板照射紫外線，進行黏著劑之UV硬化。將該試片投入至60℃、相對濕度95%之恆溫恆濕槽中，靜置300小時後取出。將試片之偏光板與標準偏光板以正交偏光之方式配置，利用光學顯微鏡(Olympus製造之「MX61L」、倍率10倍)對試片之偏光板之角隅附近進行觀察，測定產生了褪色之區域之寬度(距偏光板之端部之距離)。將實施例1及比較例5之顯微鏡觀察像示於圖4。 [評價結果] 將上述各實施例及比較例之雙面附黏著劑之偏光板中之正面側黏著片之積層構成、積層黏著片之物性(其中，比較例4、5為單層黏著片之特性)及評價結果示於表3。關於實施例3，儲存模數示出UV硬化前之值，透濕度示出UV硬化後之數值。 [表3]
Figure 106139847-A0304-0003
 於使用單層之丙烯酸系黏著片L2作為正面側黏著片之比較例5中，無氣泡及顯示不均，並且發揮出由黏著片獲得之印刷階差吸收性，然而如圖5B所示，加濕試驗後之偏光板之端部之褪色顯著，加濕耐久性較差。另一方面，於使用單層之橡膠系黏著片A5作為正面側黏著片之比較例4中，加濕試驗後之偏光板之端部之褪色得到抑制，但觀察到因正面透明板之印刷階差導致之氣泡之混入及顯示不均。由該等結果可知，於設置於單面保護偏光板上之正面側黏著片為單層之情形時，難以兼具階差吸收性及耐濕性。 相對於此，得知在與單面保護膜之偏光元件相接而設置有橡膠系之第一黏著劑層、並在第一黏著劑層上設置有丙烯酸系之第二黏著劑層的實施例1~8中，能夠兼具階差吸收性及耐濕性。 實施例6與比較例1之第一黏著劑層及第二黏著劑層之組成相同，但在比較例1中，端部之褪色量變大。認為其原因在於：比較例1中，第一黏著劑層之厚度較小、透濕度較大，故而自正面側黏著片之側面滲入之水分容易轉移至偏光元件之端面附近，因水分產生碘之褪色。 實施例1、實施例7、實施例8及比較例3之第一黏著劑層及第二黏著劑層之組成相同，各自之厚度不同。於該等實施例及比較例中，亦發現第一黏著劑層之厚度越大則偏光板端部之褪色量越小之傾向，得知低透濕度之第一黏著劑層有助於提高耐久性。 於第二黏著劑層之厚度較小且第一黏著劑層之厚度較大之比較例3中，加濕試驗後之偏光板之端部之褪色得到抑制，但觀察到因正面透明板之印刷階差導致之氣泡之混入及顯示不均。認為其原因在於：厚度較大之第一黏著劑層之黏彈性行為成為積層黏著片整體之黏彈性行為之支配性因素，黏著片之G'80 較大，因此階差吸收性不充分。 於第一黏著劑層與第二黏著劑層之厚度相等之實施例8中，因正面透明板之印刷階差導致之氣泡之混入得到抑制，但確認到輕微之顯示不均。認為其原因在於：與第二黏著劑層之厚度較大之其他實施例相比，實施例8之黏著片之階差吸收性較小。 實施例1、實施例3、實施例4及比較例2均使用厚度為25 μm之橡膠系黏著片A1作為第一黏著劑層，第二黏著劑層之丙烯酸系黏著劑之組成不同。於該等實施例及比較例中，加濕試驗後之偏光板之端部之褪色量均同等，因此得知低透濕度之第一黏著劑層有助於提高耐久性。 於第二黏著劑層之儲存模數較高之比較例2中，發現因正面透明板之印刷階差導致之氣泡之混入及顯示不均。於實施例4中，因正面透明板之印刷階差導致之氣泡混入得到抑制，但確認到輕微之顯示不均。另一方面，於實施例1、2中，無氣泡及顯示不均，黏著片具有良好之階差吸收性。 根據以上結果得知，藉由於單面保護偏光板之偏光元件露出面設置低透濕度之第一黏著劑層與儲存模數之溫度依存性較大且G'80 較小之第二黏著劑層之積層黏著片，可賦予較高之耐久性及階差吸收性，並且能夠實現圖像顯示裝置之薄型化。Fig. 1 is a cross-sectional view showing one form of a polarizing plate with an adhesive. The polarizing plate 1 with an adhesive includes a front side adhesive sheet 20 on the first main surface of the polarizing plate 10. The front side adhesive sheet 20 is an adhesive sheet used to attach the front transparent member to the visible side of the polarizing plate during the formation of the image display device. The front side adhesive sheet 20 has a laminated structure of a first adhesive layer 21 arranged in contact with the polarizing element 11 of the polarizing plate 10 and a second adhesive layer 22 arranged on the first adhesive layer 21, and the first The adhesive layer 21 is arranged in contact with the polarizing element 11 of the polarizing plate 10. Fig. 2 is a schematic cross-sectional view showing one form of an image display device provided with a front transparent member on the visible side surface. In the image display device 100, the polarizing plate 10 is arranged between the front transparent member 70 provided with the printing portion 76 on the transparent plate 71 and the image display unit 60. The polarizing plate 10 and the image display unit 60 are bonded via the cell-side adhesive sheet 30, and the polarizing plate 10 and the front transparent member 70 are bonded via the front-side adhesive sheet 20. [Single-side protective polarizing plate] As the polarizing plate 10, use a polarizing plate with a transparent protective film 15 attached to only one side of the polarizing element 11 (hereinafter, a polarizing plate with a transparent protective film provided only on one side of the polarizing element may be used 10 is described as "single-side protective polarizing plate"). By using a single-sided protective polarizing plate as the polarizing plate arranged on the viewing side of the image display unit, the image display device can be made thinner. <Polarizing element> The polarizing element 11 is a polyvinyl alcohol-based film containing iodine. As the material of the polyvinyl alcohol-based film applied to the polarizing element, polyvinyl alcohol or its derivatives are used. Examples of derivatives of polyvinyl alcohol include polyvinyl formal, polyvinyl acetal, etc., as well as olefins such as ethylene and propylene, and unsaturated carboxylic acids such as acrylic acid, methacrylic acid, and crotonic acid. Modifiers such as alkyl esters and acrylamides. Polyvinyl alcohol is usually used with a degree of polymerization of about 1,000 to 10,000 and a degree of saponification of about 80 mol% to 100 mol%. The polarizing element is obtained by performing iodine dyeing and stretching treatment on the polyvinyl alcohol-based film. The thickness of the polarizing element is preferably about 1 μm-50 μm. As the polarizing element, a thin polarizing element with a thickness of 10 μm or less can also be used. Examples of thin polarizing elements include those described in Japanese Patent Laid-Open No. 51-069644, Japanese Patent Laid-Open No. 2000-338329, WO2010/100917, Japanese Patent No. 4693205, Japanese Patent No. 4751481, etc. The polarizing element. Such a thin polarizing element can be obtained, for example, by a manufacturing method including a step of extending a polyvinyl alcohol-based resin layer and a resin base material for stretching in the state of a laminate, and a step of performing iodine dyeing. <Transparent protective film> A transparent protective film 15 for protecting the polarizing element 11 is provided on one surface (first main surface) of the polarizing element 11. The transparent protective film 15 may also have the functions of an optical compensation film for the purpose of expanding the viewing angle, etc., and a quarter-wavelength plate for forming a circular polarizing plate together with the polarizing element 11. Examples of the material constituting the transparent protective film 15 include resin materials excellent in transparency, mechanical strength, and thermal stability. Specific examples of such resin materials include: cellulose resins such as triacetyl cellulose, polyester resins, polyether-based resins, poly-based resins, polycarbonate-based resins, and polyamide-based resins. , Polyimide resin, polyolefin resin, (meth)acrylic resin, cyclic polyolefin resin (butene resin), polyarylate resin, polystyrene resin, polyvinyl alcohol Department of resins and mixtures of these. The thickness of the transparent protective film 15 is not particularly limited, but it is preferably about 5 to 100 μm from the viewpoints of workability such as strength and handleability, film properties, and the like. The polarizing element 11 and the transparent protective film 15 are preferably bonded via an appropriate adhesive layer (not shown). [Front Side Adhesive Sheet] The adhesive-attached polarizing plate of the present invention is provided with a front side adhesive sheet 20 on the side of the single-sided protective polarizing plate 10 where the transparent protective film 15 is not provided. The front side adhesive sheet 20 is used for bonding the front transparent member 70 to the visible side of the single-sided protective polarizing plate 10. The front side pressure-sensitive adhesive sheet 20 is a laminated pressure-sensitive adhesive sheet provided with at least two adhesive layers. The first adhesive layer 21 is arranged in contact with the polarizing element 11, and a second adhesive layer 22 is provided on the first adhesive layer 21. When the front side adhesive sheet 20 includes two layers of the first adhesive layer 21 and the second adhesive layer 22, the polarizing plate 1 with adhesive is provided with the first adhesive layer in sequence on the single-sided protective polarizing plate 10 21 and the second adhesive layer 22. The front side adhesive sheet 20 preferably has a moisture permeability of 150 g/m 2 ･24 hours or less. By providing the front side adhesive sheet 20 with low moisture permeability in contact with the polarizing element 11, the transfer of moisture from the outside to the polarizing element 11 can be reduced, and the deterioration of the polarizing element under high humidity environment can be suppressed. The front side adhesive sheet 20 preferably has a storage modulus G'at 80°C 80 1×10 5 Pa below. By using the front side adhesive sheet 20 with a small storage modulus at high temperature when bonding the polarizing plate 10 and the front transparent member 70, it has a step absorbency, even when the front transparent member 70 has a printing step It can also suppress the mixing of bubbles near the printing level or the uneven display caused by stress and strain. From the viewpoint of thinning, the thickness of the front-side pressure-sensitive adhesive sheet 20 is preferably 250 μm or less. <The first adhesive layer> The first adhesive layer 21 arranged in contact with the polarizing element 11 preferably has a moisture permeability of 150 g/m 2 ･24 hours or less. By providing an adhesive layer with low moisture permeability in contact with the polarizing element 11, even when the image display device is exposed to a high humidity environment, the deterioration of the polarizing element 11 can be suppressed. The moisture permeability of the first adhesive layer 21 is preferably 120 g/m 2 ･24 h or less, more preferably 100 g/m 2 ･24 h or less, 60 g/m is particularly preferred 2 ･24 h or less, the best is 40 g/m 2 ･24 hours or less. The moisture permeability is the value measured according to the moisture permeability test of JIS Z0208 (cup method), and the permeable area is 1 m within 24 hours at 40°C and 92% relative humidity 2 The weight of the water vapor of the sample. The image display unit 60 is attached to the attached surface of the transparent protective film 15 of the single-sided protective polarizing plate 10, and the front transparent member 70 is attached to the polarizing element 11 of the single-sided protective polarizing plate 10 via the front side adhesive sheet 20 In the image display device 100, moisture may transfer to the polarizing element 11 from the transparent protective film 15 attachment surface (first main surface) and the front side adhesive sheet 20 attachment surface (second main surface). The single-sided protective polarizing plate generally tends to increase the amount of water transfer from the side of the second main surface where the transparent protective film is not provided to the polarizing element. It is considered that the transfer of water from the second main surface side to the polarizing element 11 includes the transfer of water from the attachment surface (main surface) of the front side adhesive sheet 20 and the transfer of water from the side surface of the front side adhesive sheet 20. In an image display device in which a front transparent member such as a front transparent plate or a touch panel is provided on the visible side surface, the front transparent member 70 has the effect of suppressing the penetration of moisture from the main surface of the image display device. Therefore, it is possible to suppress the transfer of moisture from the front side pressure-sensitive adhesive sheet attachment surface of the second main surface to some extent. On the other hand, the front side adhesive sheet 20 as an interlayer filler provided between the polarizing plate 10 and the front transparent member 70 has step absorbency due to the increase in thickness, so moisture passes through the side surface of the front side adhesive sheet 20 The amount of transfer to the polarizing element 11 becomes larger. When the previous adhesive sheet for interlayer filling is arranged on the single-sided protective polarizer, due to the influence of moisture transferred from the side surface of the adhesive sheet to the polarizing element, discoloration is likely to occur near the end surface of the polarizing element. In contrast to this, by providing the first adhesive layer 21 with low moisture permeability in contact with the polarizing element 11, the amount of moisture transferred from the side surface of the front-side adhesive sheet 20 to the polarizing element 11 can be reduced, and the moisture-induced Deterioration of polarizing element. When the moisture permeability of the second adhesive layer 22 is large, there is moisture infiltrating from the side of the second adhesive layer 22, but the moisture that penetrates into the second adhesive layer 22 is from the low moisture permeability of the first adhesive layer 21 is blocked, so the transfer to the polarizing element 11 is suppressed. Therefore, if the first adhesive layer 21 has low moisture permeability, even when the thickness of the front side adhesive sheet 20 is large, the transfer of moisture to the polarizing element 11 can be reduced, and the deterioration of the polarizing element can be suppressed. From the viewpoint of thinning, the thickness d of the first adhesive layer 21 1 It is preferably 50 μm or less, more preferably 40 μm or less, and still more preferably 35 μm or less. From the viewpoint of thinning, it is preferable that the thickness of the first adhesive layer be as small as possible. On the other hand, the moisture permeability has an inverse relationship with the thickness, and the moisture permeability tends to increase as the thickness decreases for sheets containing the same material. In order to set the moisture permeability to the above range, the thickness of the first adhesive layer 21 is preferably 5 μm or more, more preferably 10 μm or more. The storage modulus G'at 25℃ of the first adhesive layer 21 25 Preferably 1×10 4 Pa~1×10 8 Pa, more preferably 5×10 4 Pa~1×10 7 Pa, more preferably 1×10 5 Pa~5×10 6 Pa. Storage modulus G'at 80℃ of the first adhesive layer 21 80 Preferably 5×10 3 Pa~5×10 7 Pa, more preferably 1×10 4 Pa~5×10 6 Pa, more preferably 3×10 4 Pa~1×10 6 Pa. (Composition of the first adhesive layer) As long as the adhesive constituting the first adhesive layer 21 satisfies the above-mentioned moisture permeability, its composition is not particularly limited, and acrylic polymers, rubber-based polymers, and silicon can be selected as appropriate. Ketone-based polymers, polyesters, polyurethanes, polyamides, polyvinyl ethers, vinyl acetate/vinyl chloride copolymers, modified polyolefins, epoxy-based, and fluorine-based polymers are used as base polymers. The front side adhesive sheet is disposed on the front side of the image display device, so it is preferable that the first adhesive layer 21 and the second adhesive layer 22 have excellent optical transparency. Specifically, it is preferable that each of the first adhesive layer 21 and the second adhesive layer 22 has a haze of 1.0% or less and a total light transmittance of 90% or more. In terms of achieving low moisture permeability even with a small thickness, the first adhesive layer 21 is preferably a rubber-based adhesive layer containing a rubber-based polymer as a main component. Here, the "main component" means that the first adhesive layer (or, based on the total solid content of the adhesive composition used to form the first adhesive layer) contains 40% by weight or more of the rubber-based polymer Things. The rubber-based polymer is a polymer that exhibits rubber elasticity in a temperature range around room temperature. As the rubber-based polymer, it is preferable to use at least one selected from the group consisting of natural rubber, synthetic rubber, and thermoplastic elastomer. Examples of synthetic rubbers include: polyisobutylene (PIB), butadiene rubber (BR), isoprene rubber (IR), isobutylene-isoprene rubber (IIR), styrene-butadiene rubber (SBR) ), chloroprene rubber (CR), acrylonitrile-butadiene rubber (NBR), butadiene-isoprene-styrene random copolymer, isoprene-styrene random copolymer, Binary ethylene-propylene rubber (EPR), ternary ethylene-propylene rubber (EPT), acrylic rubber, polyurethane rubber, etc. Among them, from the viewpoint of transparency and light resistance, polyisobutylene (PIB) and butyl rubber (IIR) are preferred, and polyisobutylene (PIB) is particularly preferred. Examples of thermoplastic elastomers include: styrene-ethylene-butylene-styrene block copolymer (SEBS), styrene-isoprene-styrene block copolymer (SIS), styrene-butylene Diene-styrene block copolymer (SBS), styrene-ethylene-propylene-styrene block copolymer (SEPS; hydrogenated product of SIS), styrene-ethylene-propylene block copolymer (SEP; styrene -Hydrogenated isoprene block copolymer), styrene-isobutylene-styrene block copolymer (SIBS) and other styrene-based thermoplastic elastomers; polyurethane-based thermoplastic elastomers; Polyester-based thermoplastic elastomer; blended-based thermoplastic elastomers such as a polymer blend of polypropylene and EPT (ternary ethylene-propylene rubber). Among them, from the viewpoint of transparency and light resistance, a styrene-based thermoplastic elastomer is preferred, and a styrene-ethylene-propylene-styrene block copolymer (SEPS) is particularly preferred. <Second Adhesive Layer> The second adhesive layer 22 arranged at a distance from the polarizing element 11 has a function of imparting step absorbency to the front-side adhesive sheet 20. In order to have step absorbency, the second adhesive layer 22 preferably has a storage modulus G'at 80°C 80 1.5×10 5 Pa below, more preferably 1×10 5 Pa or less, more preferably 7×10 4 Pa below. When the storage modulus under the high temperature of the second adhesive layer 22 is low, the fluidity during vacuum heating or autoclave heating and bonding is relatively high, and the adhesive easily enters the vicinity of the step difference, so it can be suppressed Air bubbles are mixed near the level difference. In order to prevent the adhesive from overflowing from the end surface of the polarizing plate under the heating state during lamination, G'of the second adhesive layer 22 80 Preferably 1×10 3 Pa or more, more preferably 3×10 3 Pa or more. Storage modulus G'at 25℃ of the second adhesive layer 22 25 Preferably 1×10 4 Pa~1×10 7 Pa, more preferably 4×10 4 Pa~6×10 6 Pa, more preferably 6×10 4 Pa~1×10 6 Pa. If the storage modulus at room temperature is 1×10 4 Pa or more can reduce the adhesion of the adhesive to the cutting blade or the overflow of the adhesive from the end surface when the polarizing plate with the adhesive is cut to a specific size. If the storage modulus at room temperature is 1×10 7 Pa below, can prevent the adhesive cracking or defect in the cut surface when the polarizing plate with adhesive is cut to a specific size. Also, if the G'of the second adhesive layer 22 25 Within the above range, the cohesive force required for processability and handling properties can be maintained, and the initial adhesion at the time of bonding can be ensured. The second adhesive layer 22 is preferably a storage modulus G'at 80°C 80 And storage modulus G'under 25℃ 25 Than G' 25 /G' 80 It is 3.5 or more, more preferably 5 or more, and still more preferably 7 or more. The temperature dependence of the storage modulus is relatively large, G' 25 /G' 80 When the value is large, the fluidity at room temperature is small, which can inhibit the transfer of the adhesive to the cutting blade and the overflow of the adhesive from the end surface during cutting, and the fluidity is high when heated, and the adhesive is easy to enter Near the printing level difference, it is possible to suppress the mixing of air bubbles near the printing level difference or the display unevenness of the image display device. G'of the second adhesive layer 22 25 /G' 80 The upper limit is not particularly limited. In consideration of adhesiveness during bonding at room temperature or fluidity during heating, etc., it is preferably 100 or less, and more preferably 50 or less. The storage modulus G'is read according to the method described in JIS K7244-1 "Plastic-Dynamic Mechanical Properties Test Method", at a frequency of 1 Hz in the range of -50 ℃ ~ 150 ℃ and 5 ℃ / The temperature rise rate per minute is determined by the value at the specific temperature when the measurement is performed. The adhesive constituting the adhesive layer is light-curing or thermo-curing. When the polarizing plate 10 and the front transparent member 70 are cured after bonding, only the storage modulus of the adhesive before curing (when bonding) (G' 25 , G' 80 And G' 25 /G' 80 ) Is within the above range. Since the cutting of the adhesive sheet and the bonding with the front transparent member are performed before hardening, the above-mentioned purpose can be achieved by adjusting the storage modulus of the second adhesive layer 22 before hardening. In order to have step absorbency, the thickness d of the second adhesive layer 22 2 It is preferably 50 μm or more, more preferably 60 μm or more, and still more preferably 70 μm or more. By increasing the thickness of the second adhesive layer 22, the level difference absorbability can be improved, and the mixing of bubbles near the printing level difference or the display unevenness of the image display device can be suppressed. The thickness d of the second adhesive layer 22 2 The upper limit is not particularly limited. From the viewpoint of thinning and preventing the adhesive from overflowing from the end surface, it is preferably 250 μm or less, more preferably 200 μm or less, and still more preferably 180 μm or less. (Composition of the second adhesive layer) As long as the adhesive constituting the second adhesive layer 22 satisfies the above characteristics, the composition is not particularly limited, and acrylic polymer, rubber polymer, silicon Ketone-based polymers, polyesters, polyurethanes, polyamides, polyvinyl ethers, vinyl acetate/vinyl chloride copolymers, modified polyolefins, epoxy-based, and fluorine-based polymers are used as base polymers. As described above, the second adhesive layer is preferably excellent in optical transparency. In terms of achieving both viscoelastic properties and high transparency that can impart step absorbability, the second adhesive layer 22 is preferably an acrylic adhesive layer containing an acrylic polymer as a main component. Here, the "main component" means that the second adhesive layer (or, based on the total solid content of the adhesive composition used to form the second adhesive layer) contains 40% by weight or more of acrylic polymer Things. As the acrylic polymer, it is preferable to use a monomer unit of an alkyl (meth)acrylate as a main skeleton. In addition, in this specification, "(meth)acrylic acid" means acrylic acid and/or methacrylic acid. As the alkyl (meth)acrylate, it is preferable to use an alkyl (meth)acrylate whose alkyl group has 1 to 20 carbon atoms. The content of the aforementioned alkyl (meth)acrylate is preferably 40% by weight or more, more preferably 50% by weight or more, and still more preferably 60% by weight or more with respect to the total amount of monomer components constituting the acrylic polymer. The acrylic polymer may also be a copolymer of multiple alkyl (meth)acrylates. The arrangement of the monomer units may be random or block. The alkyl group of the alkyl (meth)acrylate may have branches. By using a branched alkyl (meth)acrylate, it is easy to impart flexibility to the adhesive, and an acrylic adhesive layer having the above storage modulus can be easily formed. As the branched alkyl (meth)acrylate, 2-ethylhexyl (meth)acrylate, isooctyl (meth)acrylate, isononyl (meth)acrylate, and (meth)acrylate can be preferably used. Isodecyl acrylate, isotetradecyl (meth)acrylate, isooctadecyl (meth)acrylate, etc. The acrylic polymer preferably contains an acrylic monomer unit having a crosslinkable functional group as a copolymerization component. In the case of a crosslinkable functional group, the acrylic polymer can be thermally crosslinked, photocured, etc., so that the acrylic adhesive has a higher cohesive force. Examples of acrylic monomers having a crosslinkable functional group include hydroxyl group-containing monomers and carboxyl group-containing monomers. Among them, it is preferable to contain a hydroxyl group-containing monomer as a copolymerization component of the acrylic polymer. When the acrylic polymer has a hydroxyl-containing monomer as the monomer unit, it has a tendency to improve the crosslinkability of the acrylic polymer and suppress the white turbidity of the adhesive in a high temperature and high humidity environment, and a higher transparency can be obtained. Adhesive. Examples of hydroxyl-containing monomers include: 2-hydroxyethyl (meth)acrylate, 2-hydroxypropyl (meth)acrylate, 4-hydroxybutyl (meth)acrylate, and 6-hydroxy (meth)acrylate Hexyl ester, 8-hydroxyoctyl (meth)acrylate, 10-hydroxydecyl (meth)acrylate, 12-hydroxylauryl (meth)acrylate, or (4-hydroxymethylcyclohexyl)methyl acrylate, etc. The content of the hydroxyl-containing monomer unit is preferably 0.01% by weight to 20% by weight, more preferably 0.1% by weight to 15% by weight, and even more preferably 0.5% by weight relative to the total amount of monomer units constituting the acrylic polymer ~10% by weight. If the content of the hydroxyl-containing monomer unit exceeds the above range, the cohesive force of the second adhesive layer may increase excessively, and the level difference absorbability may decrease. The acrylic polymer preferably contains a monomer unit with higher polarity such as a nitrogen-containing monomer in addition to the hydroxyl-containing monomer unit. By containing monomer units with higher polarity such as nitrogen-containing monomer units in addition to hydroxyl-containing monomer units, it is possible to achieve both high adhesion and suppression of white turbidity under high temperature and high humidity environments. Examples of nitrogen-containing monomers include: N-vinylpyrrolidone, methylvinylpyrrolidone, vinylpyridine, vinylpiperidone, vinylpyrimidine, vinylpiperidine, vinylpyrrolidone, vinyl Vinyl pyrrole, vinyl imidazole, vinyl azole, vinyl morpholine, (meth)acrylomorpholine, N-vinylcarboxamides, N-vinyl caprolactam and other vinyl monomers; Cyanoacrylate monomers such as acrylonitrile and methacrylonitrile. Among them, N-vinylpyrrolidone and (meth)acrylomorpholine are preferably used. The content of the nitrogen-containing monomer unit is preferably 3% by weight to 45% by weight, more preferably 5% by weight to 40% by weight, and still more preferably 7% by weight relative to the total amount of monomer units constituting the acrylic polymer ~30% by weight. Regarding the acrylic polymer of the second adhesive layer, the total of the content of the hydroxyl-containing monomer unit and the content of the nitrogen-containing monomer unit relative to the total amount of the monomer units is preferably 3% by weight to 50% by weight, and more It is preferably 5% by weight to 40% by weight, and more preferably 7% by weight to 30% by weight. If the sum of the content of the hydroxyl-containing monomer unit and the content of the nitrogen-containing monomer unit is in the above range, it is easy to form an acrylic adhesive layer having moderate cohesiveness and flexibility during heating. The monomer component used to form the acrylic polymer may also contain a multifunctional monomer component. By containing multifunctional monomers as comonomer components, the storage modulus at room temperature tends to increase. A multifunctional single-system monomer having at least two polymerizable functional groups (for example, vinyl groups). The amount of polyfunctional monomer used varies according to its molecular weight or number of functional groups, etc., relative to all monomer components forming the (meth)acrylic polymer, preferably 5% by weight or less, more preferably 3% by weight or less , More preferably, it is 1 weight% or less. If the usage amount of the multifunctional monomer exceeds 5% by weight, the flexibility of the adhesive will decrease, causing bubbles near the level difference or display unevenness. Acrylic polymers can be prepared by known polymerization methods such as solution polymerization, UV polymerization, bulk polymerization, and emulsion polymerization. In terms of transparency, water resistance, cost, etc. of the adhesive, a solution polymerization method or an active energy ray polymerization method (such as UV polymerization) is preferred. As a solvent for solution polymerization, ethyl acetate, toluene, etc. are usually used. In the preparation of acrylic polymers, polymerization initiators such as photopolymerization initiators or thermal polymerization initiators can be used according to the type of polymerization reaction. The photopolymerization initiator is not particularly limited as long as it starts the photopolymerization. For example, benzoin ether-based photopolymerization initiators, acetophenone-based photopolymerization initiators, and α-ketol-based photopolymerization initiators can be used. Aromatic sulfonyl chloride-based photopolymerization initiator, photoactive oxime-based photopolymerization initiator, benzoin-based photopolymerization initiator, benzophenone-based photopolymerization initiator, benzophenone-based photopolymerization initiator Starter, ketal-based photopolymerization initiator, 9-oxysulfur
Figure 106139847-A0304-xxxx-3
It is a photopolymerization initiator, an phosphine oxide-based photopolymerization initiator, etc. As the thermal polymerization initiator, for example, an azo-based initiator, a peroxide-based initiator, a redox-based initiator obtained by combining a peroxide and a reducing agent (for example, persulfate and sulfite) can be used. The combination of sodium bisulfate, the combination of peroxide and sodium ascorbate, etc.). In order to adjust the molecular weight of the acrylic polymer, a chain transfer agent can also be used. The chain transfer agent can receive free radicals from the growing polymer chain to stop the elongation of the polymer, and the chain transfer agent that receives the free radicals can attack the monomer and start the polymerization again. Therefore, by using a chain transfer agent, the increase in the molecular weight of the acrylic polymer can be suppressed without reducing the concentration of free radicals in the reaction system, so that an adhesive with moderate flexibility can be obtained. As the chain transfer agent, for example, α-thioglycerin, lauryl mercaptan, glycidyl mercaptan, thioglycolic acid, 2-mercaptoethanol, thioglycolic acid, 2-ethylhexyl thioglycolic acid can be preferably used. , 2,3-Dimercapto-1-propanol and other mercaptans. When a multifunctional monomer is used as the monomer component to form an acrylic polymer in addition to a monofunctional monomer, the monofunctional monomer can be polymerized first to form a prepolymer composition with a low degree of polymerization (prepolymerization) , And add a multifunctional monomer to the prepolymer composition (prepolymerized slurry), and polymerize the prepolymer and the multifunctional monomer (post-polymerization). By carrying out the prepolymerization of the prepolymer in this way, the branch point derived from the polyfunctional monomer component can be uniformly introduced into the acrylic polymer. In addition, a mixture of the prepolymer composition and unpolymerized monomer components (adhesive composition) may be coated on the substrate, and then post-polymerized on the substrate to form an adhesive sheet. Since the prepolymer composition has low viscosity and excellent coatability, it can be Improve the productivity of the adhesive sheet and make the thickness of the adhesive sheet uniform. The prepolymer composition can be, for example, a composition obtained by mixing the monomer component (referred to as "monomer component A") constituting the acrylic polymer with a polymerization initiator (referred to as "prepolymer forming combination物") is prepared by partial polymerization (prepolymerization). Furthermore, the monomer component A in the composition for forming a prepolymer is preferably a monofunctional monomer such as an alkyl (meth)acrylate or a polar group-containing monomer among the monomer components constituting the acrylic polymer Element. The monomer component A may contain not only a monofunctional monomer but also a multifunctional monomer. For example, the composition for forming a prepolymer may contain a part of the polyfunctional monomer component that becomes the raw material of the acrylic polymer. After the prepolymer is polymerized, the remaining part of the polyfunctional monomer component may be added and supplied later. polymerization. In addition to the monomer component A and the polymerization initiator, the composition for forming a prepolymer may optionally contain a chain transfer agent and the like. The polymerization method of the composition for forming a prepolymer is not particularly limited. From the viewpoint of adjusting the reaction time to set the molecular weight (polymerization rate) of the prepolymer in the desired range, UV light or the like is preferred. Polymerization under active light irradiation. The polymerization initiator or chain transfer agent used in the prepolymerization is not particularly limited. For example, the above-mentioned photopolymerization initiator and chain transfer agent can be used. The polymerization rate of the prepolymer is not particularly limited. From the viewpoint of setting the viscosity suitable for coating on the substrate, it is preferably 3% by weight to 50% by weight, more preferably 5% by weight to 40% by weight . The polymerization rate of the prepolymer can be adjusted to a desired range by adjusting the type or amount of the photopolymerization initiator, the irradiation intensity of active light such as UV light, and the irradiation time. In addition, the polymerization rate of the prepolymer was calculated by the following formula based on the weight of the prepolymer composition before and after heating (drying) when heated at 130°C for 3 hours. In the case of prepolymerization by solution polymerization, the weight obtained by subtracting the amount of solvent from the total weight of the prepolymer composition is used as the weight before drying in the following formula to calculate the polymerization rate. The polymerization rate of the prepolymer composition (%) = the weight after drying/the weight before drying×100. The monomer component (called "monomer component B") that constitutes the acrylic polymer is mixed in the above prepolymer composition ) And mixing polymerization initiator, chain transfer agent, silane coupling agent, crosslinking agent, etc. as necessary to form an adhesive composition. The monomer component B preferably contains a polyfunctional monomer. The monomer component B may contain a monofunctional monomer in addition to the polyfunctional monomer. The photopolymerization initiator or chain transfer agent used in the post-polymerization is not particularly limited, and for example, the above-mentioned photopolymerization initiator or chain transfer agent can be used. When the polymerization initiator used in the prepolymerization does not deactivate but remains in the prepolymer composition, the addition of the polymerization initiator for post polymerization can be omitted. The acrylic polymer may also have a cross-linked structure if necessary. The formation of the crosslinked structure is performed, for example, by adding a crosslinking agent after prepolymerization or after polymerization of the base polymer. As the cross-linking agent, isocyanate-based cross-linking agents, epoxy-based cross-linking agents, azoline-based cross-linking agents, aziridine-based cross-linking agents, carbodiimide-based cross-linking agents, metal chelate-based cross-linking agents can be used Common users such as crosslinking agents. The content of the crosslinking agent is usually in the range of 0 to 5 parts by weight, preferably 0 to 3 parts by weight relative to 100 parts by weight of the base polymer. If the content of the crosslinking agent is too much, the flexibility of the adhesive will decrease, and bubbles or display unevenness near the level difference will easily occur. When a crosslinking agent is contained in the adhesive composition, it is preferable to perform a crosslinking treatment by heating before bonding to the adherend to form a crosslinked structure. The heating temperature or heating time in the cross-linking treatment is appropriately set according to the type of cross-linking agent used. Usually, the cross-linking is performed by heating in the range of 20°C to 160°C for about 1 minute to 7 days. The second adhesive layer 22 may be a light-curing type or a heat-curing type adhesive. By using a light-curing or thermosetting adhesive as the second adhesive layer 22, the polarizing plate 10 and the front transparent member 70 are bonded via the front-side adhesive sheet 20, and the second adhesive layer 22 is cured to increase Storage modulus of large adhesive layer. Therefore, even when the image display device is exposed to a high-temperature environment, the flow of the adhesive can be suppressed, and long-term reliable adhesiveness can be achieved that is unlikely to generate bubbles or peel off. In particular, in terms of easy curing after being bonded to the front transparent member, a light-curing adhesive is preferred. The light-curing adhesive contains a light-curing component in addition to the base polymer. As the photocurable component, it is preferable to use a radically polymerizable compound (ethylenically unsaturated compound) having a carbon-carbon double bond (C=C bond). The radically polymerizable compound may exist in the adhesive composition in the form of a monomer or an oligomer, and may also be bonded to a functional group such as a hydroxyl group of the base polymer. The hardening type adhesive preferably contains a polymerization initiator (a photopolymerization initiator or a thermal polymerization initiator). When the radical polymerizable compound is present in the adhesive composition in the form of a monomer or oligomer, it is preferable to use a polyfunctional polymerizable compound having two or more polymerizable functional groups in one molecule. Examples of polyfunctional polymerizable compounds include compounds having two or more C=C bonds in one molecule, one C=C bond and epoxy group in one molecule, aziridine, oxazoline, hydrazine, and methylol Compounds such as polymerizable functional groups. Among them, a polyfunctional polymerizable compound having two or more C=C bonds in one molecule like a polyfunctional acrylate is preferable. By mixing a radical polymerizable compound having a functional group capable of bonding with the functional group of the base polymer and a radical polymerizable functional group with the base polymer, the radical polymerizable functional group can be introduced into the base polymer , And the adhesive composition is made into a hardened adhesive. The functional group capable of bonding to the functional group of the base polymer is preferably an isocyanate group. Since the isocyanate group and the hydroxyl group of the base polymer form a urethane bond, it is possible to easily introduce a radical polymerizable functional group into the base polymer. As a method of photocuring, a method of irradiating active rays such as ultraviolet rays to a system containing a photocurable compound and a photopolymerization initiator is preferred. Especially in terms of high photosensitivity and abundant materials to choose from, a system using ethylenically unsaturated compounds and photo-radical generators is preferred. When the second adhesive layer 22 is a light-curing adhesive, the content of the light-curing compound relative to 100 parts by weight of the entire adhesive composition is preferably 2-50 parts by weight, more preferably 5-30 parts by weight share. <Additives in the adhesive composition> The adhesive composition for forming the first adhesive layer 21 and the adhesive composition for forming the second adhesive layer 22 may contain various additives in addition to the base polymer. For example, in order to adjust the adhesive force, a silane coupling agent may be added to the adhesive composition. The silane coupling agent may be used singly, or two or more of them may be used in combination. Especially when the second adhesive layer is made of acrylic polymer as the main component, the adhesive composition used to form the second adhesive layer preferably contains a silane coupling agent. The addition amount of the silane coupling agent is usually about 0.01 to 5 parts by weight, preferably about 0.03 to 2 parts by weight, relative to 100 parts by weight of the acrylic polymer. An adhesive imparting agent may also be added to the adhesive composition as needed. Especially when the first adhesive layer 21 is an adhesive layer containing a rubber-based polymer as a main component, from the viewpoint of improving the adhesion with the polarizing element 11, it is preferably contained in the adhesive composition Adhesion imparting agent. As the adhesion-imparting agent, for example, terpene-based adhesion-imparting agents, styrene-based adhesion-imparting agents, phenol-based adhesion-imparting agents, rosin-based adhesion-imparting agents, epoxy-based adhesion-imparting agents, and dicyclopentadiene-based adhesion-imparting agents can be used. Agents, polyamide-based adhesion-imparting agents, ketone-based adhesion-imparting agents, elastic system adhesion-imparting agents, etc. In particular, as the adhesion-imparting agent used in the first adhesive layer, the terpene-based adhesion-imparting agent is preferred in terms of excellent compatibility with rubber-based materials and transparency. Examples of terpene-based adhesion-imparting agents include terpene polymers such as α-pinene polymers, β-pinene polymers, and dipentene polymers, terpene phenol resins, styrene-modified terpene resins, and aromatics. Family modified terpene resin, hydrogenated terpene resin (hydrogenated terpene resin) and other modified terpene resins. The adhesive imparting agent contained in the first adhesive layer 21 preferably has a softening point of about 70°C to 200°C, more preferably about 100°C to 180°C. The softening point is the measured value obtained by JIS K2207 "Ring and Ball Softening Point Test Method". The content of the adhesion imparting agent in the first adhesive layer 21 is preferably 100 parts by weight or less, more preferably 80 parts by weight or less, and still more preferably 50 parts by weight or less relative to 100 parts by weight of the rubber-based base polymer. The lower limit of the content of the adhesion imparting agent is not particularly limited. In order to obtain the effect of improving the adhesion with the polarizing element, it is preferably 1 part by weight or more, more preferably 5 parts by weight or more. The second adhesive layer may also contain an adhesive imparting agent. The use of the adhesive imparting agent in the second adhesive layer can help adjust the temperature dependence of the storage modulus. From the viewpoint of imparting the required temperature dependence to the storage modulus of the second adhesive layer 22, the adhesive imparting agent contained in the second adhesive layer preferably has a softening point of about 50°C to 150°C, more preferably It is about 70℃~140℃. Preferably, at least one of the first adhesive layer 21 and the second adhesive layer 22 contains an ultraviolet absorber. Generally, the transparent protective film provided on the surface of the polarizing element contains an ultraviolet absorber in order to prevent the deterioration of the polarizing element caused by ultraviolet rays. On the other hand, since the single-sided protective polarizer 10 is not provided with a transparent protective film on the attachment surface of the front-side adhesive sheet 20, it is preferable that the first adhesive layer 21 and/or the second adhesive layer 22 have ultraviolet absorbing properties. , Thereby preventing the deterioration of the polarizing element 11 caused by ultraviolet rays. Examples of ultraviolet absorbers include: benzophenone-based ultraviolet absorbers, benzotriazole-based ultraviolet absorbers, salicylic acid-based ultraviolet absorbers, oxaniline-based ultraviolet absorbers, and cyanoacrylate-based ultraviolet absorbers Agents, three UV absorbers, etc. The content of the ultraviolet absorber is preferably 0.01 to 15 parts by weight, more preferably 0.1 to 10 parts by weight relative to 100 parts by weight of the base polymer of the adhesive. The front side adhesive sheet 20 preferably has a light transmittance of 15% or less at a wavelength of 380 nm, and more preferably 10% or less. In addition to the components exemplified above, plasticizers, softeners, deterioration inhibitors, fillers, colorants, antioxidants, surfactants, and anti-oxidants can also be added to the adhesive composition within the range that does not impair the characteristics of the adhesive. Additives such as electrostatic agents. The adhesive composition used to form the first adhesive layer 21 preferably has a rubber-based polymer content of 40% by weight or more, more preferably 50% by weight or more, and even more preferably 60% by weight or more. The adhesive composition used to form the second adhesive layer 22 preferably has an acrylic polymer content of 40% by weight or more, more preferably 50% by weight or more, and even more preferably 60% by weight or more. <Formation of Adhesive Layer> As a method of forming the adhesive layer, various methods can be used. Specifically, for example, roll coating, touch roll coating, gravure coating, reverse coating, roll brushing, spray coating, dip roll coating, bar coating, knife coating, air knife coating, Methods such as curtain coating, die lip coating, extrusion coating using die nozzle coater, etc. Among them, it is preferable to use a die nozzle coating machine, and it is more preferable to use a die nozzle coating machine using an injection die nozzle or a slit die nozzle. When the base polymer of the adhesive composition is a solution polymerized polymer, it is preferable to dry the solvent after coating. As a drying method, a suitable method can be appropriately adopted according to the purpose. The heating and drying temperature is preferably 40°C to 200°C, more preferably 50°C to 180°C, and particularly preferably 70°C to 170°C. The drying time can be appropriately used. The drying time is preferably 5 seconds to 20 minutes, more preferably 5 seconds to 15 minutes, and particularly preferably 10 seconds to 10 minutes. When the adhesive composition contains a crosslinking agent, it can be crosslinked by heating after coating on the substrate. The heating temperature and heating time can be appropriately set according to the type of crosslinking agent used, and the crosslinking is usually performed within the range of 20°C to 160°C by heating for 1 minute to 7 days. The heating used to dry the adhesive after coating can also act as the heating for cross-linking. The method of laminating the first adhesive layer and the second adhesive layer is not particularly limited. The first adhesive layer and the second adhesive layer can be individually formed into an adhesive sheet and then the two can be overlapped, or one adhesive layer can be formed as an adhesive sheet and then another adhesive can be applied on it Layers to obtain a laminated adhesive sheet. In addition, a laminated adhesive sheet may be formed by co-extrusion of the composition for forming the first adhesive layer and the composition for forming the second adhesive layer. The front side adhesive sheet 20 may be a two-layer laminated adhesive sheet including a first adhesive layer 21 and a second adhesive layer 22, and may also be placed between the first adhesive layer and the second adhesive layer and/or on the first adhesive layer. There are other adhesive layers on the second adhesive layer 22. From the viewpoint of productivity and thinning of the adhesive sheet, the front-side adhesive sheet 20 preferably includes two layers of the first adhesive layer 21 and the second adhesive layer 22. <Characteristics of Adhesive Sheet> The first adhesive layer 21 arranged in contact with the polarizing element 11 of the single-sided protective polarizing plate 10 is composed of an adhesive with low moisture permeability, and the second adhesive is arranged spaced apart from the polarizing element 11 The layer 22 is composed of a soft adhesive with a small storage modulus at high temperature. The first adhesive layer 21 with low moisture permeability is provided in contact with the polarizing element 11, even when the moisture permeability of the second adhesive layer 22 is high, it can be blocked by the first adhesive layer 21 The transfer of moisture to the polarizing element 11 can suppress the deterioration of the polarizing element due to the transfer of moisture from the side surface of the front-side adhesive sheet 20. On the other hand, adhesives with low moisture permeability including rubber-based polymers usually have a lower glass transition temperature. Therefore, the storage modulus of the adhesive at room temperature (25°C) and heating (80°C) is more dependent on the temperature. Small, storage modulus G'at 80℃ 80 And storage modulus G'under 25℃ 25 Ratio G' 25 /G' 80 Usually 3 or less. Even if an adhesive imparting agent is used in the first adhesive layer 21 with a rubber-based polymer as the main component, it is difficult to increase G' 25 /G' 80 . To reduce G'by making the first adhesive layer contain a large amount of adhesion imparting agent or plasticizer 80 In the case of step absorbency, the storage modulus G'at room temperature (25℃) 25 It also decreases, so it is easy to cause the adhesive to overflow from the end surface or transfer to the cutting knife. Since a soft adhesive is laminated on the first adhesive layer 21 with low moisture permeability as the second adhesive layer 22, the adhesive can enter the vicinity of the printing step of the front transparent member, and therefore the mixing of bubbles near the step can be suppressed. Furthermore, the flexibility of the entire front-side adhesive sheet 20 can be maintained, and therefore, the display unevenness of the peripheral portion of the screen caused by the printing step can be suppressed. As mentioned above, the second adhesive layer 22 preferably has a storage modulus G'at 80°C 80 And storage modulus G'under 25℃ 25 Ratio G' 25 /G' 80 It is 3.5 or more, more preferably 5 or more, and still more preferably 7 or more. G'of the second adhesive layer 22 25 /G' 80 It is preferably greater than G'of the first adhesive layer 21 25 /G' 80 . G'of the second adhesive layer 22 25 /G' 80 Preferably, G'of the first adhesive layer 21 25 /G' 80 2 times or more, more preferably 3 times or more, and still more preferably 4 times or more. G'of the first adhesive layer and the second adhesive layer 25 /G' 80 The ratio is an index indicating the difference in temperature dependence of the storage modulus of the adhesive layers. The greater the ratio, the greater the difference in viscoelastic behavior. The thickness d of the second adhesive layer 22 2 Preferably greater than the thickness d of the first adhesive layer 21 1 . The thickness d of the first adhesive layer 21 1 And the thickness d of the second adhesive layer 22 2 Ratio d 2 /d 1 Preferably it is 1.5-15, more preferably 2-10, and still more preferably 2.5-8. By making the thickness of the second adhesive layer relatively larger than that of the first adhesive layer, in the overall viscoelastic behavior of the front side adhesive sheet 20 obtained by laminating the first adhesive layer 21 and the second adhesive layer 22, the second The viscoelasticity of the adhesive layer dominates. Therefore, the level difference absorbency of the front side pressure-sensitive adhesive sheet 20 is improved, and it is possible to suppress mixing of air bubbles in the vicinity of the printing level difference or display unevenness of the image display device. From the viewpoint of high fluidity during heating and suppression of adhesive overflow from the end surface, the storage modulus G'at 80°C of the front side adhesive sheet 20 80 Preferably 1×10 3 Pa~1.5×10 5 Pa, more preferably 3×10 3 Pa~1×10 5 Pa, more preferably 5×10 3 Pa~7×10 4 Pa. From the viewpoint of preventing the adhesive from overflowing from the end surface or the transfer of the adhesive to the cutting blade when cutting the polarizing plate with the adhesive to a specific size, and suppressing the cracking or defect of the adhesive, the front side adhesive sheet 20 of 25 Storage modulus G'at ℃ 25 Preferably 1×10 4 Pa~1×10 7 Pa, more preferably 4×10 4 Pa~6×10 6 Pa, more preferably 6×10 4 Pa~1×10 6 Pa. Storage modulus G'at 80℃ of the front side adhesive sheet 20 80 And storage modulus G'under 25℃ 25 Ratio G' 25 /G' 80 Preferably it is 2-100, more preferably 5-50, and still more preferably 7-30. As described above, by making the thickness of the second adhesive layer 22 relatively larger than that of the first adhesive layer 21, in the viscoelastic behavior of the entire front side adhesive sheet 20, the viscoelasticity of the second adhesive layer dominates. , Can increase the temperature dependence of the storage modulus of the front side adhesive sheet 20, and can reduce G' 25 /G' 80 Adjust the value to within the above range. When the first adhesive layer and/or the second adhesive layer constituting the front-side adhesive sheet 20 contain a light-curing or thermosetting adhesive, as described above, the storage modulus of the adhesive sheet before curing is preferable For the above range. On the other hand, the moisture permeability of the front side adhesive sheet is related to the humidification durability of the image display device after the front transparent plate and the polarizing element are bonded, so it is preferably the value after curing (after the image display device is formed) 150 g/m as mentioned above 2 ･24 hours or less. [Formation of Polarizing Plate with Adhesive] The method of attaching the front side adhesive sheet 20 to the single-sided protective polarizing plate 10 is not particularly limited. The laminated adhesive sheet obtained by laminating the first adhesive layer 21 and the second adhesive layer can be formed in advance, and the first adhesive layer 21 of the laminated adhesive sheet can be attached to the polarizing element 11; it can also be applied to the polarizing element 11 The first adhesive layer 21 and the second adhesive layer 22 are sequentially attached to the upper surface. The first adhesive layer forming composition may be coated on the polarizing element 11 to form the first adhesive layer 21, and the second adhesive layer 22 may be formed on the polarizer 11 by coating or transfer. In addition, a laminated adhesive sheet may be formed on the polarizing element 11 by co-extrusion of the first adhesive layer forming composition and the second adhesive layer forming composition to obtain an adhesive-attached polarizing plate. As shown in FIG. 1, it is preferable to attach the protective sheet 41 to the front side adhesive sheet 20 of the polarizing plate 1 with the adhesive in a peelable manner. The protective sheet is used for the purpose of protecting the exposed surface of the adhesive before the adhesive is used for bonding with the adherend. The base material used in the formation (coating) of the adhesive layer can also be directly used as the protective sheet 41 on the front-side adhesive sheet. As a constituent material of the protective sheet 41, a plastic film such as polyethylene, polypropylene, polyethylene terephthalate, or polyester film is preferably used. The thickness of the protective sheet is usually about 5 to 200 μm, preferably about 10 to 150 μm. The protective sheet can also be demoulded and antifouling treated with silicone-based, fluorine-based, long-chain alkyl-based or fatty acid amide-based mold release agents, silica powder, etc., or coated or kneaded. , Evaporation type, etc. anti-static treatment. In particular, by appropriately performing peeling treatments such as silicone treatment, long-chain alkyl treatment, and fluorine treatment on the surface of the protective sheet, the releasability of the self-adhesive can be further improved. [Polarizing plate with adhesive on both sides] The front side adhesive sheet 20 is arranged in contact with the polarizing element 11 of the single-sided protective polarizing plate 10, and another adhesive sheet is arranged on the attachment surface of the transparent protective film 15 (Unit side adhesive sheet) 30, thereby obtaining a polarizing plate with adhesive on both sides as shown in FIG. 3. In the state shown in FIG. 3, a protective sheet 41 is releasably attached to the front side adhesive sheet 20 of the polarizing plate 2 with a double-sided adhesive, and a protective sheet 41 is releasable on the unit side adhesive sheet 30 A protective sheet 42 is attached. If such a double-sided adhesive-attached polarizing plate with adhesive layers pre-attached on both sides of the polarizing plate 10 is used, after the polarizing plate is attached to the surface of the image display unit, it can be omitted to attach another polarizer to the polarizing plate. The steps of the adhesive sheet can simplify the manufacturing steps of the image display device. <Cell-side adhesive sheet> The thickness of the cell-side adhesive sheet 30 is preferably 3 μm to 30 μm, more preferably 5 μm to 27 μm, and still more preferably 10 μm to 25 μm. As the unit side adhesive sheet, various adhesives used for bonding the polarizing plate and the image display unit can be used. As the adhesive for the unit-side adhesive sheet, it is preferable to use an acrylic adhesive. The unit side adhesive sheet 30 is preferably a storage modulus G'at 20°C 25 1×10 4 Pa~1×10 7 Pa, more preferably 5×10 4 Pa~5.0×10 6 Pa, more preferably 1×10 5 Pa~1×10 6 Pa. If the G'of the adhesive sheet on the side of the unit 25 Within the above-mentioned range, it is possible to exhibit moderate adhesiveness and suppress the transfer of the adhesive to the dicing blade or the like during cutting, or the cracking and chipping of the adhesive. [Image display device] Fig. 2 is a schematic cross-sectional view showing one form of an image display device. The adhesive-attached polarizing plate of the present invention is suitable for forming an image display device 100 that is provided with a touch panel or A front transparent member 70 such as a front transparent plate is provided with an image display unit 60 such as a liquid crystal cell or an organic EL cell on the main surface of the transparent protective film 15 side. In the image display device 100, the front side adhesive sheet 20 is used for bonding the polarizing element 11 of the single-sided protective polarizing plate 10 and the front transparent member 70. Examples of the front transparent member 70 include a front transparent plate (window layer), a touch panel, and the like. As the front transparent plate, a transparent plate with appropriate mechanical strength and thickness can be used. As such a transparent plate, for example, a transparent resin plate such as acrylic resin or polycarbonate resin, or a glass plate can be used. As the touch panel, any type of touch panel such as a resistive film type, an electrostatic capacitance type, an optical type, an ultrasonic type, etc. can be used. In the case of using the double-sided adhesive-attached polarizing plate shown in FIG. 3, the bonding method of the image display unit 60 and the adhesive-attached polarizing plate 2 and the front transparent member 70 and the adhesive-attached polarizing plate 2 The bonding method is not particularly limited, and after peeling off the protective sheets 41 and 42 bonded to the respective surfaces of the front-side adhesive sheet 20 and the unit-side adhesive sheet 30, they can be bonded by various known methods. From the viewpoint of improving the workability of bonding or the axis accuracy of the polarizing plate, it is preferable to peel off the protective sheet 42 from the surface of the unit side adhesive sheet 30, and then to pass the polarizing plate 10 and the image display unit through the adhesive sheet 30. 60 The unit side bonding step of bonding, after which, the protective sheet 41 is peeled off from the surface of the front side adhesive sheet 20, and the front side bonding of the polarizing plate 10 and the front transparent member 70 through the front side adhesive sheet 20 is performed step. After the front transparent member 70 is attached to the front side adhesive sheet 20, it is preferable to perform air bubbles near the non-flat parts such as the interface between the front side adhesive sheet 20 and the front transparent member 70 or the printed part 76 of the front transparent member 70 Removal of defoaming. As the defoaming method, suitable methods such as heating, pressurizing, and depressurizing can be used. For example, it is preferable to perform bonding while suppressing the mixing of bubbles under reduced pressure and heating, and thereafter, for the purpose of suppressing delayed foaming, etc., pressurization is performed while heating by autoclave treatment or the like. When the front-side adhesive sheet 20 contains a photocurable or thermosetting adhesive, it is preferable to cure the polarizing plate 10 and the front transparent member 70 after bonding. By hardening the adhesive layer, the bonding reliability between the polarizing plate 10 and the front transparent member 70 can be improved. The hardening method of the adhesive layer is not particularly limited. In the case of photocuring, a method of irradiating active rays such as ultraviolet rays through the front transparent member 70 is preferred. [Examples] Hereinafter, examples and comparative examples are given to describe the present invention in more detail, but the present invention is not limited to these examples. [Method for evaluating the physical properties of adhesive and adhesive sheet] <Storage modulus> Laminate a plurality of adhesive sheets to obtain an adhesive sheet with a thickness of approximately 1.5 mm, which is used as a test sample. In addition, in the measurement of the storage modulus of the laminated adhesive sheet, a thickness of about 1.5 mm obtained by alternately laminating the first adhesive layer and the second adhesive layer was used as the measurement sample. Regarding the photocurable adhesive sheet M1, each adhesive sheet before and after curing was used as a measurement sample. Using the "Advanced Rheometric Expansion System (ARES)" manufactured by Rheometric Scientific, the dynamic viscoelasticity was measured under the following conditions, and the storage modulus (G' at 25°C and 80°C) was read from the measurement results. 25 , G' 80 ). (Measurement conditions) Deformation mode: Torsion measurement frequency: 1 Hz Heating rate: 5°C/min Measurement temperature: -50°C~150°C range Shape: parallel plate 8.0 mm
Figure 02_image001
<Water vapor permeability> Peel off the release film on one side of the adhesive sheet, and paste a 25 μm triacetyl cellulose film on the exposed surface (water vapor permeability: 1070 g/m 2 ･24 h), and then peel off the other side of the isolation film, according to the humidity permeability test of JIS Z0208 (cup method) in a constant temperature and humidity tank with a temperature of 40 ℃ and a relative humidity of 92% for 24 h, and calculate Water permeability. With regard to the photocurable adhesive sheet M1 and the laminated adhesive sheet of Example 3 using the adhesive sheet M1, the adhesive sheet was bonded to a triacetyl cellulose film and UV cured, and then the moisture permeability test was performed. The moisture permeability obtained by this measurement is the moisture permeability of the laminate of the triacetyl cellulose film and the adhesive sheet, but since the moisture permeability of the triacetyl cellulose film is sufficiently greater than the moisture permeability of the adhesive sheet, it can be considered as the laminate The moisture permeability = the moisture permeability of the adhesive sheet. <Ultraviolet Transmittance> Measure the transmittance spectrum of the adhesive sheet with an ultraviolet-visible spectrophotometer, and read the transmittance at a wavelength of 380 nm. [Production of rubber adhesive sheet] <Production of adhesive sheet A1~A5> 100 parts by weight of polyisobutylene (PIB; "OPPANOL B80" manufactured by BASF, weight average molecular weight: about 750,000, glass transition temperature: -63°C) 7.8 parts by weight of a benzotriazole-based ultraviolet absorber ("TINUVIN 384-2" manufactured by BASF) and 300 parts by weight of toluene were mixed to prepare an adhesive composition A. The above-mentioned adhesive composition A was applied to the release treatment surface of the release film (polyester film with a silicone release treatment on one side) so that the thickness after drying as shown in Table 1 was applied, and then heated at 130°C The solvent was removed for 2 minutes to produce an adhesive sheet. <Preparation of Adhesive Sheet B1> Using the adhesive composition B without the addition of an ultraviolet absorber, an adhesive sheet B1 was produced in the same manner as described above. <Production of Adhesive Sheets C1 and C2> 100 parts by weight of polystyrene-poly(ethylene/propylene)-polystyrene block copolymer ("SEPTON 2063" manufactured by Kuraray, styrene content: 13%; SEPS) 8.9 parts by weight and 300 parts by weight of toluene were mixed with a three-dimensional ultraviolet absorber ("TINOSORB S" manufactured by BASF) to prepare an adhesive composition C. The above-mentioned adhesive composition C was applied to the release-treated surface of the release film so as to have the thickness after drying shown in Table 1, and then heated at 130° C. for 2 minutes to remove the solvent to produce an adhesive sheet. The composition of the above-mentioned adhesive composition A to C and the characteristics of each adhesive sheet (thickness, moisture permeability and storage modulus) are shown in Table 1. [Table 1]
Figure 106139847-A0304-0001
[Production of Acrylic Adhesive Sheet] <Production of Adhesive Sheet K1~K3> (Preparation of Adhesive Composition) Put 40 parts by weight of 2-ethylhexyl acrylate (2EHA) and isostearyl acrylate ( ISA) 40 parts by weight, N-vinylpyrrolidone (NVP) 19 parts by weight, 4-hydroxybutyl acrylate (4HBA) 1 part by weight, and 1-hydroxycyclohexyl phenyl ketone (BASF) as a photopolymerization initiator 0.1 parts by weight of the manufactured "IRGACURE184"), irradiated with ultraviolet rays in a nitrogen environment to obtain a prepolymer composition with a polymerization rate of 10%. To 100 parts by weight of the prepolymer composition, 2,2-dimethoxy-1,2-diphenylethane-1-one ( "IRGACURE651" manufactured by BASF; IRG651), trimethylolpropane triacrylate (TMPTA) as a multifunctional monomer, α-thioglycerin (TGR) as a chain transfer agent, and 3-glycidol as a silane coupling agent Oxypropyl trimethoxysilane ("KBM403" manufactured by Shin-Etsu Chemical), and then uniformly mixed to prepare adhesive composition K. (Preparation of Adhesive Sheet) The above-mentioned adhesive composition K was applied to the release-treated surface of the release film so as to have the thickness shown in Table 2 to form a coating layer, and another release film was pasted on the coating layer The peeling treatment surface. Then, use it to make the irradiation intensity of the irradiation surface directly below the lamp become 5 mW/cm 2 The way, the position is adjusted by the black light lamp for UV irradiation, until the cumulative amount of light reaches 3000 mJ/cm 2 , The polymerization proceeds to make acrylic adhesive sheet. <Adhesive sheets L1 and L2> With respect to 100 parts by weight of the prepolymer composition, 0.7 parts by weight of three 𠯤 UV absorbers ("TINOSORB S" manufactured by BASF) were added to the adhesive composition K to prepare an adhesive Composition L. Using this adhesive composition L, coating and UV polymerization were performed in the same manner as described above to produce an adhesive sheet L1 with a thickness of 100 μm and an adhesive sheet L2 with a thickness of 125 μm. <Adhesive sheet M1> 72 parts by weight of 2EHA, 13 parts by weight of NVP, 14 parts by weight of 2-hydroxyethyl acrylate (2HEA), 0.2 parts by weight of azobisisobutyronitrile (AIBN) as a thermal polymerization initiator, and 0.12 parts by weight of TGR as a chain transfer agent and 150 parts by weight of ethyl acetate were put into the reaction vessel, stirred for 1 hour in a nitrogen atmosphere at 23° C., and replaced with nitrogen. Thereafter, the reaction was carried out at 65°C for 7 hours to obtain a solution of an acrylic base polymer having a weight average molecular weight (Mw) of 250,000. The trimethylolpropane adduct of xylylene diisocyanate as an isocyanate-based crosslinking agent ("TAKENATE D110N" manufactured by Mitsui Chemicals Co., Ltd.) was added to the acrylic base polymer solution in the blending amount shown in Table 2. ), polypropylene glycol diacrylate as a photopolymerizable multifunctional monomer ("NK ESTER APG400" manufactured by Shinnakamura Kogyo Chemical), IRGACURE651 as a photopolymerization initiator and KBM403 as a silane coupling agent, and then mixed uniformly , And prepare the adhesive composition solution. The above adhesive composition was applied to the release surface of the release film so that the thickness after drying became 100 μm, and heated at 100°C for 6 minutes, dried to remove the solvent, and the isocyanate crosslinking agent was thermally crosslinked to obtain Light-curing adhesive sheet M1. <Adhesive sheets N1 and O1> As shown in Table 2, the addition monomer composition of the prepolymer, and the addition amount of the polyfunctional monomer and ultraviolet absorber were changed, except for the same as the above-mentioned adhesive composition K Way to prepare adhesive compositions N and O. Using these adhesive compositions, adhesive sheets N1 and O1 with a thickness of 125 μm were produced in the same manner as described above. The composition of the above-mentioned adhesive composition K~O and the characteristics of each adhesive sheet (thickness, moisture permeability and storage modulus) are shown in Table 2. [Table 2]
Figure 106139847-A0304-0002
[Production of unit side adhesive sheet] (Preparation of adhesive composition) 97 parts by weight of butyl acrylate and 3 parts by weight of acrylic acid as monomer components, and azobisisobutyronitrile (AIBN) as a thermal polymerization initiator ) 0.2 parts by weight and 233 parts by weight of ethyl acetate were put into the reaction vessel together, and stirred for 1 hour in a nitrogen atmosphere at 23° C. to perform nitrogen substitution. Thereafter, the reaction was carried out at 60°C for 5 hours to obtain a solution of an acrylic base polymer with a weight average molecular weight (Mw) of 1.1 million. To this acrylic base polymer solution was added 0.8 parts by weight of trimethylolpropane toluene diisocyanate ("CORONATE L" manufactured by Nippon Polyurethane Industry) as an isocyanate-based crosslinking agent and a silane coupling agent ("KBM403 manufactured by Shin-Etsu Chemical") ") 0.1 parts by weight, and then uniformly mixed to prepare an adhesive composition solution. (Production of Adhesive Sheet) The adhesive composition was applied to the release treatment surface of the release film so that the thickness after drying became 20 μm, and dried at 100° C. for 3 minutes to remove the solvent, thereby obtaining an adhesive sheet. Then, it heated at 50 degreeC for 48 hours, and crosslinked, and obtained the cell side adhesive sheet. [Production of a single-sided protective polarizing plate] On one side (the surface of the cell side) of the polarizing element containing a 25 μm-thick stretched polyvinyl alcohol film impregnated with iodine, a polycycloolefin protective film was bonded through an adhesive to produce a single Face protection polarizing plate. [Example 1] The above-mentioned adhesive sheet A1 was attached to the exposed surface of the polarizing element of the single-sided protective polarizing plate using a roll laminator. Furthermore, the said pressure-sensitive adhesive sheet K1 was bonded on the pressure-sensitive adhesive sheet A1 using a roll laminator. After that, the above-mentioned unit side adhesive sheet was pasted on the polycycloolefin protective film of the single-sided protective polarizing plate using a roll laminator. In this way, a double-sided adhesive-attached polarizing plate is obtained. The front side adhesive sheet including the laminated adhesive sheet of the adhesive sheet A1 and the adhesive sheet K1 is provided on the exposed side of the polarizing element of the single-sided protective polarizing plate, and the polarizing plate is protected on one side The transparent protective film attachment surface is equipped with a unit side adhesive sheet. [Examples 2 to 7, Comparative Examples 1 to 3] As shown in Table 3, the composition of the front side adhesive sheet attached to the exposed surface of the polarizing element of the single-sided protective polarizer was changed. 1 Obtain a polarizing plate with adhesive on both sides in the same way. [Comparative Examples 4 and 5] The adhesive sheets attached to the visible side of the single-sided protective polarizer were changed to adhesive sheet A5 and an adhesive sheet with a thickness of 125 μm including a single layer of L2. In addition, the same as the above In the same manner as in Example 1, a polarizing plate with adhesive on both sides was obtained. [Evaluation] ＜Display unevenness＞ Remove the backlight part from the replacement upper LCD panel of Nintendo 3DS, and remove the polarizing plate on the opposite side to the backlight of the LCD panel, and then remove it with a clean cloth soaked in ethanol Adhesive on the surface of liquid crystal cell. Cut the polarizing plate with double-sided adhesive into a size of 50 mm×80 mm, then peel off the isolation film on the side surface of the cell, overlap the surface of the cell side adhesive sheet on the center of the surface of the liquid crystal cell, and use a hand roller to paste combine. After that, peel off the barrier film on the visible side surface of the polarizing plate with adhesive on both sides, and print a glass plate with black ink (0.7 mm thick × 50 mm × 100 mm, ink printing thickness = 10 μm, ink printing width on both short sides (long side direction): 15 mm each, ink printing width on both long sides (short side direction): 5 mm each) The printing surface is placed on the exposed surface of the adhesive and used The vacuum thermocompression bonding device is used for bonding (temperature 25°C, device internal pressure 50 Pa, pressure 0.3 MPa, pressure holding time 10 seconds). After that, autoclave treatment (50°C, 0.5 MPa, 15 minutes) was performed to obtain an evaluation panel. For Example 3 using a light-curing adhesive sheet, after autoclave treatment, a high-pressure mercury lamp was used to irradiate the glass plate on the viewing side with a cumulative light amount of 3000 mJ/cm 2 The UV curing of the adhesive is carried out, and the obtained is used as the evaluation panel. The evaluation panel and the image display panel of the Nintendo 3DS main body were replaced and electrically connected to obtain an evaluation image display device. Visually confirm whether there is display unevenness near the printing frame when the panel is displayed in white. If the display unevenness is not confirmed, set it as ○, and if the display unevenness is slightly observed, set it as Δ, so that the display unevenness can be easily confirmed. Set as ×. ＜Bubble＞ Cut the polarizing plate with adhesive on both sides into a size of 45 mm×75 mm, then peel off the isolating film on the side surface of the unit, and use a hand roller to affix it to a 0.2 mm thick×50 mm×100 mm glass The central part of the board. Then, in the same way as the production of the panel for evaluation of display unevenness, the surface of the visible side of the polarizing plate with adhesive on both sides was attached to the glass plate printed with black ink in a frame shape on the periphery, and then subjected to autoclave treatment. Obtain the evaluation panel. In Example 3, UV curing of the adhesive was performed after autoclave treatment in the same manner as the panel for evaluation of display unevenness, and the obtained was used as the panel for evaluation. Use a digital microscope with a magnification of 20 times to observe the vicinity of the inner side of the black ink printed part of the evaluation panel to confirm whether there are bubbles in the adhesive sheet (initial evaluation). In addition, it was put into an oven at 85°C for 48 hours, and then the presence or absence of bubbles was confirmed by the same method (evaluation after heating). In each of the initial and post-heating evaluations, those who have not confirmed bubbles are set to ○, and those who have confirmed bubbles are set to ×. <Evaluation of Humidification Durability (End Fading)> After cutting the polarizing plate with adhesive on both sides into a size of 50 mm×50 mm, overlay the alkali-free glass plates on the adhesive layers on both sides, and press by hand The rollers are used for bonding. Furthermore, in Example 3, ultraviolet rays were irradiated through the glass plate attached to the side of the first adhesive layer to perform UV curing of the adhesive. The test piece was put into a constant temperature and humidity bath at 60° C. and a relative humidity of 95%, and left to stand for 300 hours before being taken out. The polarizing plate of the test piece and the standard polarizing plate are arranged in a way of orthogonal polarization, and the corners of the polarizing plate of the test piece are observed with an optical microscope ("MX61L" manufactured by Olympus, magnification 10 times), and the color fade is measured. The width of the area (the distance from the end of the polarizing plate). The microscope observation images of Example 1 and Comparative Example 5 are shown in FIG. 4. [Evaluation result] The laminated structure of the front side adhesive sheet in the polarizing plate of the double-sided adhesive adhesive of each of the above examples and comparative examples, and the physical properties of the laminated adhesive sheet (wherein Comparative Examples 4 and 5 are the single-layer adhesive sheets) Characteristics) and evaluation results are shown in Table 3. Regarding Example 3, the storage modulus shows the value before UV curing, and the moisture permeability shows the value after UV curing. [table 3]
Figure 106139847-A0304-0003
In Comparative Example 5 using a single-layer acrylic adhesive sheet L2 as the front-side adhesive sheet, there were no air bubbles and uneven display, and the printing step absorbency obtained by the adhesive sheet was exhibited. However, as shown in FIG. 5B, After the wet test, the end of the polarizing plate faded significantly, and the humidification durability was poor. On the other hand, in Comparative Example 4 using a single-layer rubber-based adhesive sheet A5 as the front-side adhesive sheet, the end of the polarizing plate after the humidification test was inhibited from fading, but it was observed that the printing step due to the front transparent plate The mixing and display unevenness of bubbles caused by the difference. From these results, it can be seen that when the front side adhesive sheet provided on the single-sided protective polarizer is a single layer, it is difficult to have both step absorption and moisture resistance. In contrast, it is known that the first adhesive layer of rubber is provided in contact with the polarizing element of the single-sided protective film, and the second adhesive layer of acrylic is provided on the first adhesive layer Among 1 to 8, it can have both step absorbency and moisture resistance. The composition of the first adhesive layer and the second adhesive layer of Example 6 is the same as that of Comparative Example 1, but in Comparative Example 1, the amount of discoloration at the end becomes larger. It is believed that the reason is that in Comparative Example 1, the thickness of the first adhesive layer is small and the moisture permeability is large. Therefore, the moisture infiltrated from the side surface of the front-side adhesive sheet is easily transferred to the vicinity of the end face of the polarizing element, and iodine is generated by the moisture. fade. The composition of the first adhesive layer and the second adhesive layer of Example 1, Example 7, Example 8 and Comparative Example 3 are the same, and their respective thicknesses are different. In these examples and comparative examples, it is also found that the greater the thickness of the first adhesive layer, the smaller the fading amount at the end of the polarizer. It is known that the first adhesive layer with low moisture permeability helps to improve durability sex. In Comparative Example 3 in which the thickness of the second adhesive layer was small and the thickness of the first adhesive layer was large, the fading of the polarizing plate after the humidification test was suppressed, but it was observed that the printing on the front transparent plate The mixing of bubbles and uneven display caused by the level difference. It is believed that the reason is: the viscoelastic behavior of the first adhesive layer with a larger thickness becomes the dominant factor of the viscoelastic behavior of the laminated adhesive sheet as a whole, the G'of the adhesive sheet 80 Is large, so the level difference absorbability is not sufficient. In Example 8 where the thickness of the first adhesive layer and the second adhesive layer were equal, the mixing of bubbles due to the printing step of the front transparent plate was suppressed, but slight display unevenness was confirmed. The reason for this is considered to be that the step absorbency of the adhesive sheet of Example 8 is lower than that of other examples where the thickness of the second adhesive layer is larger. Example 1, Example 3, Example 4, and Comparative Example 2 all used a rubber-based adhesive sheet A1 with a thickness of 25 μm as the first adhesive layer, and the composition of the acrylic adhesive of the second adhesive layer was different. In these examples and comparative examples, the fading amount of the end of the polarizing plate after the humidification test is the same. Therefore, it is known that the first adhesive layer with low moisture permeability helps to improve durability. In Comparative Example 2 where the storage modulus of the second adhesive layer was relatively high, it was found that the mixing of air bubbles and uneven display due to the printing step difference of the front transparent plate. In Example 4, the mixing of bubbles caused by the printing step difference of the front transparent plate was suppressed, but slight display unevenness was confirmed. On the other hand, in Examples 1 and 2, there were no bubbles and uneven display, and the adhesive sheet had good step absorbency. According to the above results, the temperature dependence of the storage modulus and the first adhesive layer with low moisture permeability on the exposed surface of the polarizing element of the single-sided protective polarizer is relatively large and G' 80 The laminated adhesive sheet of the smaller second adhesive layer can impart higher durability and step absorbency, and can realize the thinning of the image display device.

1‧‧‧附黏著劑之偏光板2‧‧‧附黏著劑之偏光板10‧‧‧單面保護偏光板11‧‧‧偏光元件15‧‧‧透明保護膜20‧‧‧正面側黏著片21‧‧‧黏著劑層22‧‧‧黏著劑層30‧‧‧單元側黏著片41‧‧‧保護片42‧‧‧保護片60‧‧‧圖像顯示單元70‧‧‧正面透明構件71‧‧‧板狀透明構件76‧‧‧印刷部100‧‧‧圖像顯示裝置d1‧‧‧第一黏著劑層之厚度d2‧‧‧第二黏著劑層之厚度1‧‧‧Polarizing plate with adhesive 2‧‧‧Polarizing plate with adhesive 10‧‧‧Single-side protective polarizing plate 11‧‧‧Polarizing element 15‧‧‧Transparent protective film 20‧‧‧Adhesive sheet on the front side 21‧‧‧ Adhesive layer 22‧‧‧ Adhesive layer 30 ‧‧‧Plate transparent member 76‧‧‧Printing section 100‧‧‧Image display device d 1 ‧‧‧The thickness of the first adhesive layer d 2 ‧‧‧The thickness of the second adhesive layer

圖1係表示附黏著劑之偏光板之一形態之模式性剖視圖。 圖2係模式性地表示圖像顯示裝置之一實施形態之剖視圖。 圖3係表示雙面附黏著劑之偏光板之一形態之模式性剖視圖。 圖4係附黏著劑之偏光板之加濕耐久性(端部褪色)評價中之顯微鏡觀察像。Fig. 1 is a schematic cross-sectional view showing one form of an adhesive-attached polarizing plate. Fig. 2 is a cross-sectional view schematically showing an embodiment of the image display device. Fig. 3 is a schematic cross-sectional view showing a form of a polarizing plate with adhesive on both sides. Figure 4 is a microscope observation image in the evaluation of humidification durability (end fading) of the polarizing plate with adhesive.

1‧‧‧附黏著劑之偏光板 1‧‧‧Polarizer with adhesive

10‧‧‧單面保護偏光板 10‧‧‧Single-side protection polarizer

11‧‧‧偏光元件 11‧‧‧Polarizing element

15‧‧‧透明保護膜 15‧‧‧Transparent protective film

20‧‧‧正面側黏著片 20‧‧‧Front side adhesive sheet

21‧‧‧黏著劑層 21‧‧‧Adhesive layer

22‧‧‧黏著劑層 22‧‧‧Adhesive layer

41‧‧‧保護片 41‧‧‧Protection film

d1‧‧‧第一黏著劑層之厚度 d 1 ‧‧‧The thickness of the first adhesive layer

d2‧‧‧第二黏著劑層之厚度 d 2 ‧‧‧The thickness of the second adhesive layer

Claims (14)

一種附黏著劑之偏光板，其係配置於正面透明板或觸控面板與圖像顯示單元之間使用者，且 具備：包含含碘之聚乙烯醇系膜之偏光元件、貼合於上述偏光元件之第一主面之透明保護膜、及與上述偏光元件之第二主面相接而設置之正面側黏著片， 上述正面側黏著片為積層有至少2層之黏著劑層之積層黏著片，且具備與上述偏光元件相接而配置之第一黏著劑層及與上述偏光元件間隔而配置之第二黏著劑層， 上述正面側黏著片之80℃下之儲存模數G'80 為1×105 Pa以下，並且 上述第一黏著劑層之透濕度為150 g/m2 ･24 h以下。An adhesive-attached polarizing plate, which is arranged between the front transparent plate or the touch panel and the image display unit for the user, and is provided with: a polarizing element containing a polyvinyl alcohol film containing iodine, which is attached to the polarizer The transparent protective film on the first main surface of the element, and the front side adhesive sheet provided in contact with the second main surface of the polarizing element, the front side adhesive sheet is a laminated adhesive sheet in which at least two adhesive layers are laminated , and have arranged the adhesive layer and the second polarizing element and the first contact of the adhesive layer is disposed and the distance of the polarization element, the storage of the adhesive sheet of the front side 80 ℃ modulus G '80 to 1 ×10 5 Pa or less, and the moisture permeability of the first adhesive layer is 150 g/m 2 ･24 h or less. 如請求項1之附黏著劑之偏光板，其中上述第一黏著劑層之厚度為50 μm以下。The adhesive-attached polarizing plate of claim 1, wherein the thickness of the first adhesive layer is 50 μm or less. 如請求項1或2之附黏著劑之偏光板，其中上述第二黏著劑層之厚度為50 μm以上。The adhesive-attached polarizing plate of claim 1 or 2, wherein the thickness of the second adhesive layer is 50 μm or more. 如請求項1或2之附黏著劑之偏光板，其中上述第二黏著劑層之厚度大於上述第一黏著劑層之厚度。The adhesive-attached polarizing plate of claim 1 or 2, wherein the thickness of the second adhesive layer is greater than the thickness of the first adhesive layer. 如請求項1或2之附黏著劑之偏光板，其中上述正面側黏著片之厚度為250 μm以下。The adhesive-attached polarizing plate of claim 1 or 2, wherein the thickness of the adhesive sheet on the front side is 250 μm or less. 如請求項1或2之附黏著劑之偏光板，其中上述第一黏著劑層為含有橡膠系聚合物作為主成分之黏著劑層。The adhesive-attached polarizing plate of claim 1 or 2, wherein the first adhesive layer is an adhesive layer containing a rubber-based polymer as a main component. 如請求項1或2之附黏著劑之偏光板，其中上述第二黏著劑層為含有丙烯酸系聚合物作為主成分之黏著劑層。The adhesive-attached polarizing plate of claim 1 or 2, wherein the second adhesive layer is an adhesive layer containing an acrylic polymer as a main component. 如請求項1或2之附黏著劑之偏光板，其中上述第二黏著劑層之25℃下之儲存模數G'25 為1×104 Pa以上，且80℃下之儲存模數G'80 為1×105 Pa以下。For example, the polarizing plate with adhesive of claim 1 or 2, wherein the storage modulus G'at 25°C of the second adhesive layer 25 is 1×10 4 Pa or more, and the storage modulus G'at 80°C 80 is 1×10 5 Pa or less. 如請求項1或2之附黏著劑之偏光板，其中上述第二黏著劑層之80℃下之儲存模數G'80 與25℃下之儲存模數G'25 之比G'25 /G'80 為3.5以上。The requested item adhesive attachment of the polarizer 1 or 2, wherein the storage at 80 deg.] C and the second layer of adhesive agent modulus G '80 to the storage at 25 deg.] C modulus G' ratio of G 25 '25 / G '80 is 3.5 or more. 如請求項1或2之附黏著劑之偏光板，其中上述第一黏著劑層之80℃下之儲存模數G'80 與25℃下之儲存模數G'25 之比G'25 /G'80 為3以下。The requested item adhesive attachment of the polarizer 1 or 2, wherein the storage at 80 deg.] C above the first layer of adhesive agent modulus G '80 to the storage at 25 deg.] C modulus G' ratio of G 25 '25 / G '80 is 3 or less. 如請求項1或2之附黏著劑之偏光板，其中上述正面側黏著片之80℃下之儲存模數G'80 與25℃下之儲存模數G'25 之比G'25 /G'80 為2~100。The requested item adhesive attachment of the polarizer 1 or 2, wherein said storage at the front side of the adhesive sheet 80 ℃ modulus G '80 to the storage at 25 deg.] C modulus G' ratio of G 25 '25 / G' 80 is 2~100. 如請求項1或2之附黏著劑之偏光板，其中上述正面側黏著片之波長380 nm下之透光率為15%以下。Such as claim 1 or 2 of the polarizing plate with adhesive, wherein the light transmittance of the front side adhesive sheet at a wavelength of 380 nm is 15% or less. 如請求項1或2之附黏著劑之偏光板，其中於上述透明保護膜上進而具備單元側黏著片。Such as claim 1 or 2 of the polarizing plate with adhesive, wherein a cell side adhesive sheet is further provided on the transparent protective film. 一種圖像顯示裝置，其於圖像顯示單元之表面具備如請求項1至13中任一項之附黏著劑之偏光板、及正面透明板或觸控面板，且 上述偏光板與上述正面透明板或觸控面板係藉由上述正面側黏著片而貼合。An image display device provided with an adhesive-attached polarizing plate as in any one of Claims 1 to 13, and a front transparent plate or touch panel on the surface of an image display unit, and the polarizing plate and the front surface are transparent The board or the touch panel is attached by the above-mentioned front side adhesive sheet.
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