TWI733376B - Polarizing plate - Google Patents

Polarizing plate Download PDF

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TWI733376B
TWI733376B TW109108725A TW109108725A TWI733376B TW I733376 B TWI733376 B TW I733376B TW 109108725 A TW109108725 A TW 109108725A TW 109108725 A TW109108725 A TW 109108725A TW I733376 B TWI733376 B TW I733376B
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protective film
rubber particles
mass
meth
film
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TW109108725A
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TW202100361A (en
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佐藤栞
南條崇
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日商柯尼卡美能達股份有限公司
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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
    • 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
    • B32B27/18—Layered products comprising a layer of synthetic resin characterised by the use of special additives
    • 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
    • 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
    • B32B7/02—Physical, chemical or physicochemical properties
    • B32B7/023—Optical 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
    • C09J7/00—Adhesives in the form of films or foils
    • C09J7/20—Adhesives in the form of films or foils characterised by their carriers
    • C09J7/29—Laminated material
    • G—PHYSICS
    • G02—OPTICS
    • G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
    • G02B1/00—Optical elements characterised by the material of which they are made; Optical coatings for optical elements
    • G02B1/10—Optical coatings produced by application to, or surface treatment of, optical elements
    • G02B1/14—Protective coatings, e.g. hard coatings
    • G—PHYSICS
    • G02—OPTICS
    • G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
    • G02B5/00—Optical elements other than lenses
    • G02B5/30—Polarising elements
    • G—PHYSICS
    • G02—OPTICS
    • G02F—OPTICAL DEVICES OR ARRANGEMENTS FOR THE CONTROL OF LIGHT BY MODIFICATION OF THE OPTICAL PROPERTIES OF THE MEDIA OF THE ELEMENTS INVOLVED THEREIN; NON-LINEAR OPTICS; FREQUENCY-CHANGING OF LIGHT; OPTICAL LOGIC ELEMENTS; OPTICAL ANALOGUE/DIGITAL CONVERTERS
    • G02F1/00—Devices or arrangements for the control of the intensity, colour, phase, polarisation or direction of light arriving from an independent light source, e.g. switching, gating or modulating; Non-linear optics
    • G02F1/01—Devices or arrangements for the control of the intensity, colour, phase, polarisation or direction of light arriving from an independent light source, e.g. switching, gating or modulating; Non-linear optics for the control of the intensity, phase, polarisation or colour 
    • G02F1/13—Devices or arrangements for the control of the intensity, colour, phase, polarisation or direction of light arriving from an independent light source, e.g. switching, gating or modulating; Non-linear optics for the control of the intensity, phase, polarisation or colour  based on liquid crystals, e.g. single liquid crystal display cells
    • G02F1/133—Constructional arrangements; Operation of liquid crystal cells; Circuit arrangements
    • G02F1/1333—Constructional arrangements; Manufacturing methods
    • G02F1/1335—Structural association of cells with optical devices, e.g. polarisers or reflectors
    • 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
    • B32B2270/00—Resin or rubber layer containing a blend of at least two different 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
    • B32B2307/00—Properties of the layers or laminate
    • B32B2307/40—Properties of the layers or laminate having particular optical properties
    • B32B2307/42—Polarizing, birefringent, filtering

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  • Physics & Mathematics (AREA)
  • General Physics & Mathematics (AREA)
  • Optics & Photonics (AREA)
  • Chemical & Material Sciences (AREA)
  • Nonlinear Science (AREA)
  • Organic Chemistry (AREA)
  • Mathematical Physics (AREA)
  • Crystallography & Structural Chemistry (AREA)
  • Polarising Elements (AREA)
  • Laminated Bodies (AREA)

Abstract

本發明之偏光板依序具有保護膜A、偏光器、保護膜B與黏著劑層。保護膜A包含(甲基)丙烯酸系樹脂與橡膠粒子a。保護膜B包含(甲基)丙烯酸系樹脂與橡膠粒子b。保護膜A之剖面中，橡膠粒子之平均縱橫比為1.0~1.1；保護膜B之剖面中，橡膠粒子之平均縱橫比為1.2~3.0。保護膜B所含之(甲基)丙烯酸系樹脂係包含50~95質量%之源自甲基丙烯酸甲酯之構造單位、1~25質量%之源自苯基馬來醯亞胺之構造單位與1~25質量%之源自丙烯酸烷酯之構造單位之共聚物。The polarizing plate of the present invention has a protective film A, a polarizer, a protective film B and an adhesive layer in sequence. The protective film A contains (meth)acrylic resin and rubber particles a. The protective film B contains (meth)acrylic resin and rubber particles b. In the section of protective film A, the average aspect ratio of rubber particles is 1.0 to 1.1; in the section of protective film B, the average aspect ratio of rubber particles is 1.2 to 3.0. The (meth)acrylic resin contained in the protective film B contains 50-95% by mass of structural units derived from methyl methacrylate and 1-25% by mass of structural units derived from phenylmaleimide Copolymer with 1-25% by mass of structural units derived from alkyl acrylate.

Description

偏光板Polarizing plate

本發明有關偏光板。The present invention relates to polarizing plates.

液晶顯示裝置等之顯示裝置所用之偏光板包含偏光器與配置於其兩面之保護膜。作為保護膜，基於具有優異透明性或尺寸安定性、低吸濕性，而使用包含以聚甲基丙烯酸甲酯等之(甲基)丙烯酸系樹脂作為主成分之膜。A polarizing plate used in a display device such as a liquid crystal display device includes a polarizer and a protective film arranged on both sides of the polarizer. As the protective film, a film containing a (meth)acrylic resin such as polymethyl methacrylate as a main component is used because it has excellent transparency, dimensional stability, and low moisture absorption.

另一方面，由於(甲基)丙烯酸系樹脂膜較脆，故為了消解脆度，進而添加橡膠粒子等之彈性粒子而使用。On the other hand, since the (meth)acrylic resin film is relatively brittle, in order to eliminate the brittleness, elastic particles such as rubber particles are added and used.

作為此等使用(甲基)丙烯酸系樹脂膜之偏光板，已知有包含偏光器與配置於其兩面之2片保護膜，且2片保護膜係具有包含彈性體粒子之聚甲基丙烯酸甲酯之芯層與配置於其兩面之不含彈性體粒子之2種聚甲基丙烯酸甲酯的2層皮層之共擠出膜的偏光板(例如專利文獻1)。作為2片保護膜係使用相同膜。As these polarizing plates using (meth)acrylic resin films, there are known two protective films including a polarizer and two protective films arranged on both sides, and the two protective films have a polymethacrylate containing elastomer particles. A polarizing plate of a co-extruded film composed of a core layer of ester and a two-layer skin layer of two types of polymethyl methacrylate containing no elastomer particles arranged on both sides thereof (for example, Patent Document 1). The same film is used as the two protective film systems.

此等偏光板於製造製品的顯示裝置之際，係配合製品而衝打成特定大小及形狀。 [先前技術文獻] [專利文獻]These polarizing plates are punched into a specific size and shape in accordance with the product when manufacturing the display device of the product. [Prior Technical Literature] [Patent Literature]

[專利文獻1] 日本特開2008-40275號公報[Patent Document 1] JP 2008-40275 A

[發明欲解決之課題][The problem to be solved by the invention]

近幾年來，基於生產收率提高之觀點，以刀刃衝打偏光板之際，對偏光板彼此之留白量要求比迄今更窄。專利文獻1之偏光板所用之保護膜亦無關於包含彈性體粒子，無法抑制偏光板衝打時之龜裂(crack)，無法使偏光板彼此之留白量變窄。In recent years, based on the viewpoint of improving the production yield, when punching the polarizing plate with a knife, the requirement for the amount of white space between the polarizing plates is narrower than before. The protective film used for the polarizing plate of Patent Document 1 also does not contain elastomer particles, and cannot suppress cracks when the polarizing plate is punched, and cannot narrow the amount of white space between the polarizing plates.

且，於偏光板之衝打步驟中，刀刃自偏光板拉出之際，容易於(甲基)丙烯酸系樹脂膜與偏光器之間產生剝離，層間密著性容易降低。如此，具有層間密著性降低之偏光板的顯示裝置，於高濕環境下長時間使用時，容易因敲鍵而產生顯示不均。In addition, in the punching step of the polarizing plate, when the blade is pulled out from the polarizing plate, peeling is likely to occur between the (meth)acrylic resin film and the polarizer, and the interlayer adhesion is likely to decrease. In this way, a display device with a polarizing plate with reduced interlayer adhesion is prone to display unevenness due to key knocking when it is used for a long time in a high-humidity environment.

本發明係鑑於上述情況而完成者，其目的在於提供可抑制抽出時之龜裂或層間剝離，於高濕環境下長時間使用時之敲鍵所致之顯示不均可減低之偏光板。 [用以解決課題之手段]The present invention has been completed in view of the above circumstances, and its object is to provide a polarizing plate that can suppress cracks or delamination during extraction, and can reduce display inconsistencies caused by key tapping during long-term use in a high-humidity environment. [Means to solve the problem]

上述課題可藉由下述構成而解決。The above-mentioned problem can be solved by the following configuration.

本發明之偏光板包含偏光器、配置於前述偏光器一面之保護膜A、配置於前述偏光器另一面之保護膜B與配置於前述保護膜B之與前述偏光器相反側之面之黏著劑層，前述保護膜A包含(甲基)丙烯酸系樹脂與橡膠粒子a，前述保護膜B包含(甲基)丙烯酸系樹脂與橡膠粒子b，前述保護膜A之沿厚度方向之剖面中，前述橡膠粒子a之平均縱橫比為1.0~1.1，前述保護膜B之沿厚度方向之剖面中，前述橡膠粒子b之平均縱橫比為1.2~3.0，前述保護膜B所含之前述(甲基)丙烯酸系樹脂係相對於構成前述(甲基)丙烯酸系樹脂之全部構造單位，包含50~95質量%之源自甲基丙烯酸甲酯之構造單位、1~25質量%之源自苯基馬來醯亞胺之構造單位與1~25質量%之源自丙烯酸烷酯之構造單位之共聚物。 [發明效果]The polarizing plate of the present invention includes a polarizer, a protective film A disposed on one side of the polarizer, a protective film B disposed on the other side of the polarizer, and an adhesive disposed on the surface of the protective film B opposite to the polarizer Layer, the protective film A includes (meth)acrylic resin and rubber particles a, the protective film B includes (meth)acrylic resin and rubber particles b, and in the cross section along the thickness direction of the protective film A, the rubber The average aspect ratio of the particles a is 1.0 to 1.1. In the cross section along the thickness direction of the protective film B, the average aspect ratio of the rubber particles b is 1.2 to 3.0. The (meth)acrylic system contained in the protective film B Relative to all the structural units constituting the aforementioned (meth)acrylic resin, the resin contains 50-95% by mass of structural units derived from methyl methacrylate and 1-25% by mass of phenyl maleic acid. A copolymer of amine structural unit and 1-25% by mass of structural unit derived from alkyl acrylate. [Effects of the invention]

依據本發明，可提供可抑制衝打時之龜裂或層間剝離，於高濕環境下長時間使用之際之敲鍵所致之顯示不均可減低之偏光板。According to the present invention, it is possible to provide a polarizing plate that can suppress cracks or delamination during punching, and can reduce display inconsistencies caused by key tapping during long-term use in a high-humidity environment.

以下，針對本發明之實施形態，參考圖式詳細說明。Hereinafter, the embodiments of the present invention will be described in detail with reference to the drawings.

1. 偏光板 圖1係顯示本實施形態之偏光板100的剖面圖。1. Polarizing plate FIG. 1 is a cross-sectional view showing the polarizing plate 100 of this embodiment.

如圖1所示，本實施形態之偏光板100具有偏光器110(偏光器)、配置於其一面且包含橡膠粒子150a(橡膠粒子a)之保護膜120A(保護膜A)、配置於另一面且包含橡膠粒子150b(橡膠粒子b)之保護膜120B(保護膜B)、配置於保護膜120A與偏光器110之間之接著劑層130A(接著劑層A)、及配置於保護膜120B與偏光器110之間之接著劑層130B(接著劑層B)。As shown in FIG. 1, the polarizing plate 100 of this embodiment has a polarizer 110 (polarizer), a protective film 120A (protective film A) which is arranged on one side and includes rubber particles 150a (rubber particles a), and is arranged on the other side And includes the protective film 120B (protective film B) of rubber particles 150b (rubber particles b), the adhesive layer 130A (adhesive layer A) arranged between the protective film 120A and the polarizer 110, and the protective film 120B and The adhesive layer 130B (adhesive layer B) between the polarizers 110.

又，偏光板100進而具有配置於保護膜120B之與偏光器110相反側之面之黏著劑層140。黏著劑層140係用以將偏光板100貼附於液晶胞等之顯示元件(未圖示)之層。黏著劑層140之表面通常以剝離膜(未圖示)予以保護。In addition, the polarizing plate 100 further has an adhesive layer 140 disposed on the surface of the protective film 120B on the opposite side of the polarizer 110. The adhesive layer 140 is a layer for attaching the polarizing plate 100 to a display element (not shown) such as a liquid crystal cell. The surface of the adhesive layer 140 is usually protected by a release film (not shown).

本發明人等針對偏光板之衝打步驟中，發生龜裂或層間剝離之機制推測如下。The inventors of the present invention speculate as follows for the mechanism of cracking or interlayer peeling during the punching step of the polarizing plate.

圖2係說明偏光板100衝打步驟之推定機制的剖面圖。其中，圖2A係將刀刃160押入偏光板100時之剖面圖，圖2B係將刀刃160自偏光板100抽出時之剖面圖。FIG. 2 is a cross-sectional view illustrating the estimation mechanism of the punching step of the polarizing plate 100. As shown in FIG. 2A is a cross-sectional view when the blade 160 is pushed into the polarizing plate 100, and FIG. 2B is a cross-sectional view when the blade 160 is drawn out from the polarizing plate 100.

如圖2A所示，將刀刃160押入偏光板100之際，保護膜120A於刀刃160押入時未因刀刃160之押入而押入鄰接之層，故因刀刃押入產生之應力較小(圖2A之虛線箭頭)；保護膜120B由於因刀刃之押入而押入鄰接之層(接著劑層130B、偏光器110、接著劑層130A及保護膜120A)，故因刀刃押入產生之應力容易變大(圖2A之實線箭頭)。藉此，保護膜120B之因刀刃押入而物理變形比保護膜120A更大，且容易於廣範圍產生。藉此，押入刀刃160之際，容易於保護膜120B產生龜裂，抽出刀刃160之際，於保護膜120B與接著劑層130B之間容易產生剝離。As shown in Figure 2A, when the blade 160 is pushed into the polarizing plate 100, the protective film 120A is not pushed into the adjacent layer due to the pushing of the blade 160 when the blade 160 is pushed, so the stress generated by the pushing of the blade is small (the dotted line in Figure 2A) Arrow); because the protective film 120B is pushed into the adjacent layers (adhesive layer 130B, polarizer 110, adhesive layer 130A and protective film 120A) due to the insertion of the blade, the stress generated by the insertion of the blade is likely to increase (Figure 2A) Solid arrow). Thereby, the physical deformation of the protective film 120B due to the insertion of the blade is greater than that of the protective film 120A, and it is easy to produce in a wide range. Thereby, when the blade 160 is pushed in, cracks are likely to occur in the protective film 120B, and when the blade 160 is pulled out, peeling is likely to occur between the protective film 120B and the adhesive layer 130B.

相對於此，本發明人等發現並非如專利文獻1般將配置於偏光器一面之保護膜中所含之橡膠粒子之平均縱橫比與配置於偏光器另一面之保護膜中所含之橡膠粒子之平均縱橫比設為相同；而是藉由將保護膜120B中所含之橡膠粒子150b之平均縱橫比設為比保護膜120A中所含之橡膠粒子150a之平均縱橫比更高，可抑制龜裂或層間剝離(參考圖2A)。In contrast, the inventors of the present invention found that the average aspect ratio of the rubber particles contained in the protective film arranged on one side of the polarizer and the rubber particles contained in the protective film arranged on the other side of the polarizer are not the same as in Patent Document 1. The average aspect ratio is set to be the same; but by setting the average aspect ratio of the rubber particles 150b contained in the protective film 120B to be higher than the average aspect ratio of the rubber particles 150a contained in the protective film 120A, the tortoise can be suppressed. Cracks or delamination (refer to Figure 2A).

具體而言，將保護膜120B中所含之橡膠粒子150b之平均縱橫比調整於1.2~3.0。藉此，由於將保護膜120B中所含之橡膠粒子150b可良好地追隨因刀刃160之押入而產生之保護膜120B之變形，故可緩和應力，不容易產生龜裂等。尤其，藉由使橡膠粒子150b之硬度比較高(苯乙烯量較多)且設為橡膠粒子150b之硬度(苯乙烯量)＞橡膠粒子150a(苯乙烯量)之硬度，而於對保護膜B施加應力之際，由於因橡膠粒子150b拉伸而更不易產生橡膠粒子150b與(甲基)丙烯酸系樹脂之界面剝離，故藉由將平均縱橫比設為上述範圍更易於獲得效果。且，保護膜120B中由於刀刃押入時產生之硬力較少，故抽出所押入之刀刃之際，不易產生保護膜120B與接著劑層130B之層間剝離(參考圖2B)。Specifically, the average aspect ratio of the rubber particles 150b contained in the protective film 120B is adjusted to 1.2 to 3.0. Thereby, since the rubber particles 150b contained in the protective film 120B can well follow the deformation of the protective film 120B caused by the insertion of the blade 160, the stress can be relieved and cracks are not easily generated. In particular, by making the hardness of the rubber particles 150b relatively high (more styrene content) and setting the hardness of the rubber particles 150b (styrene content)> the hardness of the rubber particles 150a (styrene content), the protective film B When the stress is applied, since the rubber particles 150b are stretched and the interface peeling between the rubber particles 150b and the (meth)acrylic resin is less likely to occur, it is easier to obtain the effect by setting the average aspect ratio in the above-mentioned range. In addition, since the hard force generated when the blade is pushed in is less in the protective film 120B, when the pushed blade is pulled out, it is not easy to cause interlayer peeling between the protective film 120B and the adhesive layer 130B (refer to FIG. 2B).

再者，本發明人等發現藉由將保護膜120B所含之(甲基)丙烯酸系樹脂設為以特定比例包含源自甲基丙烯酸甲酯之構造單位(U1)、源自苯基馬來醯亞胺之構造單位(U2)與源自丙烯酸烷酯之構造單位(U3)之共聚物，而不使脆性惡化，抽出刀刃160之際的層間剝離更被抑制(參考圖2B)。尤其源自苯基馬來醯亞胺之構造單位(U2)由於平面性高，具有適度極性，故容易提高與平均縱橫比適度高且具有平面性之橡膠粒子150b之間的親和性。藉此，可抑制與橡膠粒子150b之界面剝離，藉此可抑制保護膜120B與接著劑層130B之層間剝離。Furthermore, the inventors of the present invention found that by setting the (meth)acrylic resin contained in the protective film 120B to contain the structural unit (U1) derived from methyl methacrylate in a specific ratio, the The copolymer of the structural unit (U2) of imine and the structural unit (U3) derived from alkyl acrylate does not worsen the brittleness, and the interlayer peeling when the blade 160 is drawn out is more suppressed (refer to FIG. 2B). In particular, the structural unit (U2) derived from phenylmaleimide has high flatness and moderate polarity, so it is easy to increase the affinity with the rubber particles 150b having a moderately high average aspect ratio and flatness. Thereby, the peeling of the interface with the rubber particles 150b can be suppressed, and thus the interlayer peeling of the protective film 120B and the adhesive layer 130B can be suppressed.

以下針對本實施形態之偏光板之各構成要素加以說明。Hereinafter, each component of the polarizing plate of this embodiment will be described.

1-1. 偏光器 偏光器係僅使於一定方向偏波面的光通過之元件。偏光器通常係聚乙烯醇系偏光膜。聚乙烯醇系偏光膜之例包含對聚乙烯醇系膜染色碘者與染色二色性染料者。1-1. Polarizer A polarizer is an element that only passes light on a polarization plane in a certain direction. The polarizer is usually a polyvinyl alcohol-based polarizing film. Examples of the polyvinyl alcohol-based polarizing film include those dyed with iodine and those dyed with dichroic dyes.

聚乙烯醇系偏光膜可為使聚乙烯醇系膜單軸延伸後，以碘或二色性染料染色之膜(較佳進而以硼化合物施以耐久性處理之膜)；使聚乙烯醇系膜以碘或二色性染料染色後，單軸延伸之膜(較佳進而以硼化合物施以耐久性處理之膜)。偏光器110之吸收軸通常與最大延伸方向平行。The polyvinyl alcohol-based polarizing film can be a film dyed with iodine or a dichroic dye after uniaxially stretching the polyvinyl alcohol-based film (preferably a film that is treated with a boron compound for durability); After the film is dyed with iodine or a dichroic dye, it is a uniaxially stretched film (preferably, a film subjected to durability treatment with a boron compound). The absorption axis of the polarizer 110 is generally parallel to the maximum extension direction.

作為聚乙烯醇系偏光膜例如使用日本特開2003-248123號公報、日本特開2003-342322號公報等記載之乙烯單位含量1~4莫耳%、聚合度2000~4000、皂化度99.0~99.99莫耳%之乙烯改性聚乙烯醇。As the polyvinyl alcohol-based polarizing film, for example, Japanese Patent Application Publication No. 2003-248123, Japanese Patent Application Publication No. 2003-342322 and the like described in ethylene unit content 1-4 mol%, polymerization degree 2000-4000, saponification degree 99.0-99.99 Mole% ethylene modified polyvinyl alcohol.

偏光器厚度較佳為5~30μm，基於使偏光板薄型化之觀點等，更佳為5~20μm。The thickness of the polarizer is preferably 5 to 30 μm, and from the viewpoint of making the polarizer thinner, it is more preferably 5 to 20 μm.

1-2. 保護膜A 保護膜A包含(甲基)丙烯酸系樹脂與橡膠粒子a。1-2. Protective film A The protective film A contains (meth)acrylic resin and rubber particles a.

1-2-1. (甲基)丙烯酸系樹脂 保護膜A中所含之(甲基)丙烯酸系樹脂可為包含源自甲基丙烯酸甲酯之構造單位之均聚物，亦可為包含源自甲基丙烯酸甲酯之構造單位與源自可與其共聚合之甲基丙烯酸甲酯以外之共聚合單體之構造單位的共聚物。1-2-1. (Meth) acrylic resin The (meth)acrylic resin contained in the protective film A may be a homopolymer containing a structural unit derived from methyl methacrylate, or a structural unit derived from methyl methacrylate and a It is a copolymer of structural units of copolymerized monomers other than methyl methacrylate copolymerized with it.

共聚合單體並未特別限定，可包含(甲基)丙烯酸乙酯、(甲基)丙烯酸丙酯、六員環內酯(甲基)丙烯酸酯等之甲基丙烯酸甲酯以外之烷基的碳數為1~18之(甲基)丙烯酸酯類；(甲基)丙烯酸等之α,β-不飽和酸；馬來酸、富馬酸、依康酸等之含不飽和基之二價羧酸；苯乙烯、α-甲基苯乙烯等之芳香族乙烯基類；丙烯腈、甲基丙烯腈等之α,β-不飽和腈類；馬來醯亞胺、N-取代馬來醯亞胺等之馬來醯亞胺類；馬來酸酐、戊二酸酐。共聚合單體可使用1種，亦可併用2種以上。The copolymerization monomer is not particularly limited, and may contain alkyl groups other than methyl methacrylate such as ethyl (meth)acrylate, propyl (meth)acrylate, six-membered ring lactone (meth)acrylate, etc. (Meth)acrylic esters with carbon number of 1~18; α,β-unsaturated acids such as (meth)acrylic acid; divalent unsaturated group-containing acids such as maleic acid, fumaric acid, and itaconic acid Carboxylic acid; aromatic vinyls such as styrene and α-methylstyrene; α, β-unsaturated nitriles such as acrylonitrile and methacrylonitrile; maleimines, N-substituted maleic acid Maleic imines such as imines; maleic anhydride, glutaric anhydride. One type of copolymerization monomer may be used, or two or more types may be used in combination.

其中，基於容易將膜之拉伸彈性模數調整於後述範圍之觀點，較佳為包含源自甲基丙烯酸甲酯之構造單位之均聚物(聚甲基丙烯酸甲酯)，或包含源自甲基丙烯酸甲酯之構造單位、戊二醯亞胺構造單位(例如源自(甲基)丙烯酸酯之構造單位與胺等之醯亞胺化劑反應者等)、源自戊二酸酐之構造單位或源自六員環內酯(甲基)丙烯酸酯之構造單位(內酯環構造單位)之共聚物，更佳為包含源自甲基丙烯酸甲酯之構造單位之均聚物(聚甲基丙烯酸甲酯)。Among them, based on the viewpoint that it is easy to adjust the tensile elastic modulus of the film within the range described later, it is preferable to include a homopolymer (polymethyl methacrylate) derived from a structural unit derived from methyl methacrylate, or to include The structural unit of methyl methacrylate, the structural unit of glutaric imine (for example, the structural unit derived from (meth)acrylate and the reactant of the imidizing agent of amine, etc.), the structure derived from glutaric anhydride Unit or copolymer derived from the structural unit of six-membered ring lactone (meth)acrylate (lactone ring structural unit), more preferably a homopolymer (polymethyl) containing structural unit derived from methyl methacrylate Methyl acrylate).

源自甲基丙烯酸甲酯之構造單位之含量，相對於構成(甲基)丙烯酸系樹脂之全構造單位，較佳為80~ 100質量%，更佳為90~100質量%。(甲基)丙烯酸系樹脂之單體種類或組成可藉由1 H-NMR予以特定。The content of the structural unit derived from methyl methacrylate is preferably 80-100% by mass, more preferably 90-100% by mass relative to the total structural unit constituting the (meth)acrylic resin. The monomer type or composition of the (meth)acrylic resin can be specified by 1 H-NMR.

(甲基)丙烯酸系樹脂之玻璃轉移溫度(Tg)較佳為90℃以上，更佳為100~150℃。(甲基)丙烯酸系樹脂之Tg為90℃以上之保護膜A具有良好耐熱性。The glass transition temperature (Tg) of the (meth)acrylic resin is preferably 90°C or higher, more preferably 100 to 150°C. The protective film A whose Tg of the (meth)acrylic resin is 90°C or higher has good heat resistance.

(甲基)丙烯酸系樹脂之玻璃轉移溫度(Tg)可使用DSC(Differential Scanning Calorimetry：示差掃描熱量計)，依據JIS K7121-2012或ASTM D3418-82測定。The glass transition temperature (Tg) of the (meth)acrylic resin can be measured using DSC (Differential Scanning Calorimetry), based on JIS K7121-2012 or ASTM D3418-82.

(甲基)丙烯酸系樹脂之重量平均分子量(Mw)並未特別限定，可對應於製膜法適當設定。例如保護膜A為以熔融法製膜者之情況，(甲基)丙烯酸系樹脂之重量平均分子量較佳為10萬~30萬。保護膜A為以澆鑄法製膜者之情況，(甲基)丙烯酸系樹脂之重量平均分子量較佳為50萬~300萬，更佳為60萬~200萬。(甲基)丙烯酸系樹脂之重量平均分子量若為上述範圍，則不損及製膜性，可對膜賦予充分機械強度(韌性)。The weight average molecular weight (Mw) of the (meth)acrylic resin is not particularly limited, and can be appropriately set in accordance with the film forming method. For example, when the protective film A is a film formed by a melting method, the weight average molecular weight of the (meth)acrylic resin is preferably 100,000 to 300,000. The protective film A is the case of a film formed by a casting method, and the weight average molecular weight of the (meth)acrylic resin is preferably 500,000 to 3 million, more preferably 600,000 to 2 million. If the weight average molecular weight of the (meth)acrylic resin is in the above-mentioned range, the film formability is not impaired, and sufficient mechanical strength (toughness) can be provided to the film.

(甲基)丙烯酸系樹脂之重量平均分子量(Mw)可藉由凝膠滲透層析(GPC)以聚苯乙烯換算而測定。具體而言，可使用TOSOH公司製HLC8220GPC、管柱(TOSOH公司製TSK-GEL G6000HXL-G5000HXL-G5000HXL-G4000HXL-G3000HXL串聯)而測定。測定條件與後述實施例同樣。The weight average molecular weight (Mw) of the (meth)acrylic resin can be measured in terms of polystyrene by gel permeation chromatography (GPC). Specifically, it can be measured using HLC8220GPC manufactured by TOSOH Corporation and a column (TSK-GEL G6000HXL-G5000HXL-G5000HXL-G4000HXL-G3000HXL manufactured by TOSOH Corporation in series). The measurement conditions are the same as in the examples described later.

(甲基)丙烯酸系樹脂之含量，相對於保護膜A，較佳為60質量%以上，更佳為70質量%以上。The content of the (meth)acrylic resin relative to the protective film A is preferably 60% by mass or more, and more preferably 70% by mass or more.

1-2-2. 橡膠粒子a 保護膜A所含之橡膠粒子a對保護膜A賦予韌性或柔軟性。1-2-2. Rubber particles a The rubber particles a contained in the protective film A impart toughness or flexibility to the protective film A.

保護膜A之沿厚度方向之剖面中，橡膠粒子a之平均縱橫比較佳為1.0~1.1。其原因係於偏光板之衝打步驟中，為了使因刀刃押入而於保護膜A產生之應力小於因刀刃押入而於保護膜B產生之應力，故橡膠粒子a之追隨性的調整不若橡膠粒子b般那麼需要之故。且，刀刃押入保護膜A之際，由於應力容易對橡膠粒子150a等向性施加，故橡膠粒子150a本身容易分散應力。In the cross section of the protective film A along the thickness direction, the average aspect ratio of the rubber particles a is preferably 1.0 to 1.1. The reason is that in the punching step of the polarizing plate, in order to make the stress generated in the protective film A due to the insertion of the knife edge smaller than the stress generated in the protective film B due to the insertion of the knife edge, the adjustment of the followability of the rubber particles a is not as good as that of rubber. The particle b is so needed. In addition, when the blade is pushed into the protective film A, since stress is easily applied isotropically to the rubber particles 150a, the rubber particles 150a themselves easily disperse the stress.

所謂平均縱橫比意指複數橡膠粒子a之縱橫比的平均值。所謂縱橫比意指橡膠粒子之長徑對於短徑之比(長徑/短徑)。The so-called average aspect ratio means the average value of the aspect ratios of the plurality of rubber particles a. The so-called aspect ratio means the ratio of the long diameter to the short diameter of the rubber particles (long diameter/short diameter).

保護膜A之沿厚度方向之剖面中，橡膠粒子a之長徑可測定為橡膠粒子a所外切之長方形長邊方向之長度(長邊長度)；橡膠粒子a之短徑可測定為橡膠粒子a所外切之長方形短邊方向之長度(短邊長度)。In the cross section of the protective film A along the thickness direction, the long diameter of the rubber particle a can be measured as the length of the long side of the rectangle circumscribed by the rubber particle a (long side length); the short diameter of the rubber particle a can be measured as the rubber particle a The length of the circumscribed rectangle in the short side direction (short side length).

保護膜A之沿厚度方向之剖面，具體而言係指保護膜A之沿厚度方向之剖面中，與面內慢軸平行之剖面。所謂面內慢軸係膜面中折射率為最大之軸。保護膜A之面內慢軸無法特定之情況，係指保護膜A之沿厚度方向之剖面中，與保護膜A之寬度方向(TD方向)平行之剖面。The cross section of the protective film A along the thickness direction specifically refers to the cross section of the protective film A along the thickness direction that is parallel to the in-plane slow axis. The so-called in-plane slow axis is the axis with the largest refractive index in the film plane. The situation where the in-plane slow axis of the protective film A cannot be specified refers to the cross section of the protective film A along the thickness direction that is parallel to the width direction (TD direction) of the protective film A.

橡膠粒子a之平均長徑較佳為100~400nm。橡膠粒子a之平均長徑若為100nm以上，則容易對膜賦予充分韌性，若為400nm以下，則膜的透明性不易降低。橡膠粒子a之平均長徑更佳為150~300nm。橡膠粒子之平均長徑係橡膠粒子之長徑平均值。The average long diameter of the rubber particles a is preferably 100 to 400 nm. If the average major axis of the rubber particles a is 100 nm or more, it is easy to impart sufficient toughness to the film, and if it is 400 nm or less, the transparency of the film is unlikely to decrease. The average long diameter of the rubber particles a is more preferably 150 to 300 nm. The average long diameter of the rubber particles is the average long diameter of the rubber particles.

橡膠粒子a之平均縱橫比及平均長徑可藉以下方法算出。 1) TEM觀察保護膜A之剖面。觀察區域可設為相當於保護膜A之厚度的區域，亦可設為5μm×5μm之區域。將相當於保護膜A之厚度的區域設為觀察區域之情況，測定部位可為1部位。將5μm×5μm之區域設為觀察區域之情況，測定部位可為4部位。 2) 測定所得TEM圖像中各橡膠粒子之長徑、短徑，分別算出縱橫比。自複數橡膠粒子所得之縱橫比之平均值設為「平均縱橫比」，自複數橡膠粒子所得之長徑之平均值設為「平均長徑」。The average aspect ratio and average major diameter of the rubber particles a can be calculated by the following method. 1) TEM observe the cross-section of protective film A. The observation area may be an area equivalent to the thickness of the protective film A, or may be an area of 5 μm×5 μm. When the area corresponding to the thickness of the protective film A is set as the observation area, the measurement site may be one site. When an area of 5 μm×5 μm is set as the observation area, the measurement location can be 4 locations. 2) Measure the long diameter and short diameter of each rubber particle in the obtained TEM image, and calculate the aspect ratio. The average value of the aspect ratio obtained from the plurality of rubber particles is referred to as the "average aspect ratio", and the average value of the long diameter obtained from the multiple rubber particles is referred to as the "average long diameter".

橡膠粒子a之平均縱橫比或平均長徑可藉由保護膜A之製膜條件或延伸條件而調整。為使橡膠粒子a之平均縱橫比減小時，例如較佳減低保護膜之製膜時之延伸倍率(較佳設為未延伸)。The average aspect ratio or average long diameter of the rubber particles a can be adjusted by the film forming conditions or stretching conditions of the protective film A. In order to reduce the average aspect ratio of the rubber particles a, for example, it is preferable to reduce the stretch magnification (preferably unstretched) when the protective film is formed.

此等橡膠粒子a係包含橡膠狀聚合物(交聯聚合物)之粒子。橡膠狀聚合物之例包含丁二烯系交聯聚合物、(甲基)丙烯酸系交聯聚合物及有機矽氧烷系交聯聚合物。其中，基於與甲基丙烯酸系樹脂之折射率差較小，不易損及保護膜之透明性之觀點，較佳為(甲基)丙烯酸系交聯聚合物，更佳為丙烯酸系交聯聚合物(丙烯酸系橡膠狀聚合物)。These rubber particles a are particles containing a rubber-like polymer (crosslinked polymer). Examples of rubbery polymers include butadiene-based cross-linked polymers, (meth)acrylic-based cross-linked polymers, and organosiloxane-based cross-linked polymers. Among them, from the viewpoint that the refractive index difference with methacrylic resin is small, and the transparency of the protective film is not easily damaged, the (meth)acrylic crosslinked polymer is preferred, and the acrylic crosslinked polymer is more preferred. (Acrylic rubber-like polymer).

亦即，橡膠粒子較佳係包含丙烯酸系橡膠狀聚合物(a1)之粒子。That is, the rubber particles are preferably particles containing the acrylic rubber-like polymer (a1).

(丙烯酸系橡膠狀聚合物(a1)) 丙烯酸系橡膠狀聚合物(a1)係以丙烯酸酯作為主成分之交聯聚合物。亦即，丙烯酸系橡膠狀聚合物(a1)較佳係包含源自丙烯酸酯之構造單位、源自可與其共聚合之單體之構造單位、源自1分子中具有2個以上自由基聚合性基(非共軛反應性雙鍵)之多官能性單體之構造單位之交聯聚合物。(Acrylic rubber-like polymer (a1)) The acrylic rubber-like polymer (a1) is a crosslinked polymer containing acrylic ester as a main component. That is, the acrylic rubber-like polymer (a1) preferably contains a structural unit derived from an acrylate, a structural unit derived from a monomer copolymerizable therewith, and is derived from having two or more radical polymerizable properties per molecule. It is a cross-linked polymer that is a structural unit of a multifunctional monomer of a base (non-conjugated reactive double bond).

丙烯酸酯較佳係丙烯酸甲酯、丙烯酸丁酯等之烷基的碳數1~12之丙烯酸烷酯。丙烯酸酯可為1種，亦可為2種以上。基於橡膠粒子之玻璃轉移溫度為-15℃以下之觀點，丙烯酸酯較佳至少包含碳數4~10之丙烯酸烷酯。The acrylate is preferably an alkyl acrylate having 1 to 12 carbon atoms in the alkyl group such as methyl acrylate and butyl acrylate. There may be one type of acrylate, or two or more types. Based on the viewpoint that the glass transition temperature of the rubber particles is -15°C or less, the acrylate preferably contains at least an alkyl acrylate having 4 to 10 carbon atoms.

源自丙烯酸酯之構造單位之含量，相對於構成丙烯酸系橡膠狀聚合物(a)之全部構成單位較佳為40~80質量%，更佳為45~65質量%。丙烯酸酯含量若為45質量%以上，則容易對膜賦予充分韌性。The content of the acrylate-derived structural unit is preferably 40 to 80% by mass, and more preferably 45 to 65% by mass relative to all the structural units constituting the acrylic rubber-like polymer (a). If the acrylate content is 45% by mass or more, it is easy to impart sufficient toughness to the film.

可共聚合之單體係可與丙烯酸酯共聚合之單體中之多官能性單體以外者。亦即，可共聚合單體不具有2個以上自由基聚合性基。可共聚合之單體之例包含甲基丙烯酸甲酯等之甲基丙烯酸酯；苯乙烯、甲基苯乙烯等之苯乙烯類；丙烯腈、甲基丙烯腈等之不飽和腈類等。其中，基於容易使保護膜A之拉伸彈性模數低於保護膜B之拉伸彈性模數之觀點，可共聚合之單體較佳包含苯乙烯類。The monomers that can be copolymerized in a single system are those other than the multifunctional monomers among the monomers that can be copolymerized with acrylate. That is, the copolymerizable monomer does not have two or more radical polymerizable groups. Examples of copolymerizable monomers include methacrylates such as methyl methacrylate; styrenes such as styrene and methyl styrene; unsaturated nitriles such as acrylonitrile and methacrylonitrile. Among them, from the viewpoint that it is easy to make the tensile elastic modulus of the protective film A lower than the tensile elastic modulus of the protective film B, the copolymerizable monomer preferably contains styrene.

可共聚合之單體包含苯乙烯類之情況，保護膜A中所含之橡膠粒子a之源自苯乙烯類之構造單位含量較佳少於保護膜B中所含之橡膠粒子b之源自苯乙烯類之構造單位含量。亦即丙烯酸系橡膠狀聚合物(a1)之源自苯乙烯類之構造單位含量較佳少於丙烯酸系橡膠狀聚合物(b1)之源自苯乙烯類之構造單位含量。具體而言，丙烯酸系橡膠狀聚合物(a1)之源自苯乙烯類之構造單位含量相對於構成丙烯酸系橡膠狀聚合物(a1)之全部構成單位較佳為5~55質量%，更佳為30~50質量%。源自苯乙烯類之構造單位含量若為上述範圍內，則橡膠粒子a容易調整至適當硬度。When the copolymerizable monomer contains styrene, the content of the styrene-derived structural unit of the rubber particles a contained in the protective film A is preferably less than that of the rubber particles b contained in the protective film B. The structural unit content of styrene. That is, the content of styrene-derived structural units of the acrylic rubber-like polymer (a1) is preferably less than the content of styrene-derived structural units of the acrylic rubber-like polymer (b1). Specifically, the content of the styrene-derived structural unit of the acrylic rubber-like polymer (a1) is preferably 5 to 55% by mass relative to all the structural units constituting the acrylic rubber-like polymer (a1), and more preferably It is 30-50% by mass. If the content of the styrene-derived structural unit is within the above range, the rubber particles a can be easily adjusted to an appropriate hardness.

橡膠粒子之源自苯乙烯類之構造單位含量可藉由例如以熱分解GC/MS檢測出之波峰面積比而測定。具體而言，可藉以下順序測定。 1) 首先，準備幾個苯乙烯類含量不同的以之試料，進行GC/MS測定，基於所得波鋒面積比作成校正線。 2) 其次，針對成為測定對象之試料，進行GC/MS測定，算出波鋒面積比。 3) 將上述2)所得之波鋒面積比與上述1)之校正線對照，特定出成為測定對象之試料的苯乙烯類含量。 GCMS之測定條件如以下。 測定裝置：SHIMAZU GCMS QP2010 管柱種類：Urtra Alloy-5(尺寸30m×徑0.25mm) 載體氣體種類：He 流量條件：1.8mL/分鐘 管柱烘箱溫度條件：40℃-10℃/分鐘-320℃ 介面溫度：300℃ 離子源溫度：200℃ 檢測模式：SIM(靶離子：m/z104，確認離子：m/z78)The styrene-derived structural unit content of the rubber particles can be determined by, for example, the peak area ratio detected by thermal decomposition GC/MS. Specifically, it can be measured by the following procedure. 1) First, prepare several samples with different styrene content, perform GC/MS measurement, and create a calibration line based on the obtained wave front area ratio. 2) Next, perform GC/MS measurement on the sample to be measured, and calculate the wave front area ratio. 3) Compare the wave front area ratio obtained in 2) above with the calibration line in 1) above to specify the styrene content of the sample to be measured. The measurement conditions of GCMS are as follows. Measuring device: SHIMAZU GCMS QP2010 Column type: Ultra Alloy-5 (size 30m×diameter 0.25mm) Carrier gas type: He Flow conditions: 1.8mL/min Column oven temperature conditions: 40℃-10℃/min-320℃ Interface temperature: 300℃ Ion source temperature: 200℃ Detection mode: SIM (target ion: m/z104, confirmation ion: m/z78)

多官能性單體之例包含(甲基)丙烯酸烯丙酯、氰尿酸三烯丙酯、異氰尿酸三烯丙酯、鄰苯二甲酸二烯丙酯、馬來酸二烯丙酯、己二酸二乙烯基酯、二乙烯基苯、乙二醇二(甲基)丙烯酸酯、二乙二醇(甲基)丙烯酸酯、三乙二醇二(甲基)丙烯酸酯、三羥甲基丙烷三(甲基)丙烯酸酯、四羥甲基甲烷四(甲基)丙烯酸酯、二丙二醇二(甲基)丙烯酸酯、聚乙二醇二(甲基)丙烯酸酯。Examples of multifunctional monomers include allyl (meth)acrylate, triallyl cyanurate, triallyl isocyanurate, diallyl phthalate, diallyl maleate, hexyl Divinyl diacid, divinylbenzene, ethylene glycol di(meth)acrylate, diethylene glycol (meth)acrylate, triethylene glycol di(meth)acrylate, trimethylol Propane tri(meth)acrylate, tetramethylolmethane tetra(meth)acrylate, dipropylene glycol di(meth)acrylate, polyethylene glycol di(meth)acrylate.

源自多官能性單體之構造單位之含量，相對於構成丙烯酸系橡膠狀聚合物(a1)之全部構成單位較佳為0.05~10質量%，更佳為0.1~5質量%。多官能性單體之含量若為0.05質量%以上，由於容易提高所得丙烯酸系橡膠狀聚合物(a)之交聯度，故不會過於損及所得膜之硬度、剛性，若為10質量%以下，則不易損及膜韌性。The content of the structural unit derived from the polyfunctional monomer is preferably from 0.05 to 10% by mass, and more preferably from 0.1 to 5% by mass relative to all the structural units constituting the acrylic rubber-like polymer (a1). If the content of the polyfunctional monomer is 0.05% by mass or more, the degree of crosslinking of the obtained acrylic rubber-like polymer (a) is easily increased, so the hardness and rigidity of the obtained film will not be impaired too much. If it is 10% by mass Below, the film toughness is less likely to be impaired.

包含丙烯酸系橡膠狀聚合物(a1)之粒子可為由丙烯酸系橡膠狀聚合物(a1)所成之粒子；亦可為在丙烯酸系橡膠狀聚合物(a1)之存在下，使甲基丙烯酸酯等之單體混合物至少聚合1段以上而得之由丙烯酸系接枝共聚物所成之粒子，亦即，可為具有包含丙烯酸系橡膠狀聚合物(a1)之芯部與包覆其之殼部之芯殼型粒子。The particles containing the acrylic rubber-like polymer (a1) may be particles formed from the acrylic rubber-like polymer (a1); it may also be made of methacrylic acid in the presence of the acrylic rubber-like polymer (a1) A mixture of monomers such as esters is polymerized at least one stage to form particles of acrylic graft copolymer, that is, it may have a core containing an acrylic rubber-like polymer (a1) and a particle covering it. Shell core shell particles.

構成芯殼型粒子之芯部包含丙烯酸系橡膠狀聚合物(a1)。構成芯殼型粒子之殼部包含源自甲基丙烯酸酯之構造單位之聚合物(a2)(接枝成分)。The core constituting the core-shell particles contains the acrylic rubber-like polymer (a1). The shell part constituting the core-shell particle contains a polymer (a2) (grafting component) derived from a structural unit of methacrylate.

甲基丙烯酸酯較佳係甲基丙烯酸甲酯等之烷基的碳數1~12之甲基丙烯酸烷酯。甲基丙烯酸酯可為1種，亦可為2種以上。The methacrylate is preferably an alkyl methacrylate having 1 to 12 carbon atoms in the alkyl group such as methyl methacrylate. There may be one type of methacrylate, or two or more types.

甲基丙烯酸酯之含量，相對於構成聚合物(a2)之全部構成單位較佳為50質量%以上。甲基丙烯酸酯含量若為50質量%以上，則所得膜之硬度、剛性不易降低。且基於提高與二氯甲烷等之溶劑之親和性之觀點，甲基丙烯酸酯之含量，相對於構成聚合物之全部構成單位更佳為70質量%以上。The content of the methacrylate is preferably 50% by mass or more with respect to all the constituent units of the constituent polymer (a2). If the methacrylate content is 50% by mass or more, the hardness and rigidity of the resulting film will not easily decrease. In addition, from the viewpoint of improving the affinity with solvents such as dichloromethane, the content of methacrylate is more preferably 70% by mass or more with respect to all the constituent units of the constituent polymer.

聚合物(a2)亦可進而包含源自可共聚合之其他單體之構造單位。其他單體之例包含丙烯酸甲酯、丙烯酸乙酯、丙烯酸正丁酯等之丙烯酸酯；(甲基)丙烯酸苄酯、(甲基)丙烯酸二環戊酯、(甲基)丙烯酸苯氧基乙酯等之具有脂環式構造、雜環式構造或芳香族基之(甲基)丙烯酸系單體類(含環構造之(甲基)丙烯酸系單體)。The polymer (a2) may further include structural units derived from other copolymerizable monomers. Examples of other monomers include acrylates such as methyl acrylate, ethyl acrylate, n-butyl acrylate, etc.; benzyl (meth)acrylate, dicyclopentyl (meth)acrylate, and phenoxyethyl (meth)acrylate (Meth)acrylic monomers having alicyclic structure, heterocyclic structure, or aromatic group such as ester ((meth)acrylic monomer containing ring structure).

橡膠粒子中之接枝成分的重量比率(接枝率)較佳為10~250%，更佳為25~200%，又更佳為40~200%，又再更佳為60~150%。上述質量比若為10%以上，由於殼部之比例不會過於減少，故不易損及膜之硬度或剛性。上述質量比若為250%以下，由於芯部之比例不會過於減少，故不易損及膜之韌性或脆性改善效果。The weight ratio (grafting ratio) of the graft component in the rubber particles is preferably 10 to 250%, more preferably 25 to 200%, still more preferably 40 to 200%, and still more preferably 60 to 150%. If the above-mentioned mass ratio is more than 10%, since the proportion of the shell part will not decrease too much, the hardness or rigidity of the film will not be easily damaged. If the above-mentioned mass ratio is 250% or less, since the ratio of the core part will not decrease too much, it is not easy to impair the toughness or brittleness improvement effect of the film.

接枝率之質量比係以下述方法測定。 1) 將芯殼型粒子2g溶解於甲基乙基酮50ml中，使用離心分離機(日立工機(股)製，CP60E)，以旋轉數30000rpm、溫度12℃離心1小時，分離為不溶分與可溶分(離心分離作業合計設定3次)。 2) 所得不溶分重量代入下述式，算出接枝率。 接枝率(%)=[{(二氯甲烷不溶分重量)-(丙烯酸系橡膠狀聚合物(a)之重量)}/(丙烯酸系橡膠狀聚合物(a)之重量)]×100The mass ratio of the grafting rate is determined by the following method. 1) Dissolve 2 g of core-shell particles in 50 ml of methyl ethyl ketone, use a centrifugal separator (manufactured by Hitachi Koki Co., Ltd., CP60E), centrifuge at 30,000 rpm and a temperature of 12°C for 1 hour, and separate into insoluble fractions And soluble fraction (a total of 3 centrifugal separation operations are set). 2) The obtained insoluble content weight is substituted into the following formula to calculate the grafting rate. Grafting rate (%)=[{(dichloromethane insoluble content weight)-(acrylic rubber-like polymer (a) weight))/(acrylic rubber-like polymer (a) weight)]×100

(關於物性) 橡膠粒子之玻璃轉移溫度(Tg)較佳為室溫(25℃)以下。又，橡膠粒子a之玻璃轉移溫度較佳低於橡膠粒子b之玻璃轉移溫度。橡膠粒子之玻璃轉移溫度(Tg)若滿足上述範圍，則容易對膜賦予充分韌性。橡膠粒子之玻璃轉移溫度(Tg)係以與前述相同之方法測定。(About physical properties) The glass transition temperature (Tg) of the rubber particles is preferably room temperature (25°C) or lower. In addition, the glass transition temperature of the rubber particles a is preferably lower than the glass transition temperature of the rubber particles b. If the glass transition temperature (Tg) of the rubber particles satisfies the above range, it is easy to impart sufficient toughness to the film. The glass transition temperature (Tg) of the rubber particles is measured by the same method as described above.

橡膠粒子a之玻璃轉移溫度(Tg)可藉由例如構成芯部或殼部之聚合物組成或接枝率而調整。為了降低橡膠粒子之玻璃轉移溫度(Tg)，如後述，較佳增多例如芯部之丙烯酸系橡膠狀聚合物(a1)中之烷基的碳原子數為4以上之丙烯酸酯/可共聚合單體之質量比(例如3以上，較佳4以上10以下)。The glass transition temperature (Tg) of the rubber particles a can be adjusted by, for example, the composition of the polymer constituting the core or the shell or the grafting rate. In order to lower the glass transition temperature (Tg) of the rubber particles, as will be described later, it is preferable to increase the number of acrylic acid esters/copolymerizable monomers whose alkyl groups in the acrylic rubber-like polymer (a1) in the core part have 4 or more carbon atoms. The mass ratio of the body (for example, 3 or more, preferably 4 or more and 10 or less).

保護薄膜A中橡膠粒子a之含量並未特別限定，但較佳多於保護薄膜B中橡膠粒子b之含量。具體而言，保護薄膜A中橡膠粒子a之含量相對於保護薄膜A較佳為12~25質量%，更佳為15~22質量%。橡膠粒子之含量若為12質量%以上，則容易對保護薄膜A賦予充分韌性或柔軟性，若為25質量%以下，則容易抑制內部濁度之增大。The content of the rubber particles a in the protective film A is not particularly limited, but it is preferably more than the content of the rubber particles b in the protective film B. Specifically, the content of the rubber particles a in the protective film A is preferably 12 to 25% by mass relative to the protective film A, and more preferably 15 to 22% by mass. If the content of the rubber particles is 12% by mass or more, it is easy to impart sufficient toughness or flexibility to the protective film A, and if it is 25% by mass or less, it is easy to suppress the increase in internal haze.

1-2-3. 其他成分 保護膜A可根據需要進而包含上述以外之其他成分。其他成分之例包含霧化劑。霧化劑之例包含氧化矽粒子等之無機微粒子、玻璃轉移溫度為80℃以上之有機微粒子等。1-2-3. Other ingredients The protective film A may further contain components other than the above as needed. Examples of other ingredients include atomizers. Examples of the atomizing agent include inorganic fine particles such as silica particles, and organic fine particles having a glass transition temperature of 80°C or higher.

1-2-4. 物性 (拉伸彈性模數) 保護膜A之拉伸彈性模數並未特別限定，就容易抑制衝打偏光板之際之龜裂或層間剝離之觀點，較佳低於保護膜B之拉伸彈性模數。其原因如前述，偏光板之衝打步驟中，由於因刀刃押入而於保護膜A產生之應力小於於保護膜B產生之應力，故施加於保護膜A之橡膠粒子a之負荷的調整不若保護膜B般那麼必要之故。且，保護膜A之拉伸彈性模數相對較低時，亦可減小保護膜B所受之「刀刃前端所致之應力」或「因壓入保護膜A而產生之應力」。具體而言，保護膜A之25℃下之拉伸彈性模數較佳為1.6~ 2.6GPa。1-2-4. Physical properties (Tensile modulus of elasticity) The tensile elastic modulus of the protective film A is not particularly limited, and it is preferably lower than the tensile elastic modulus of the protective film B from the viewpoint that it is easy to suppress cracking or interlayer peeling during punching of the polarizing plate. The reason is as mentioned above. In the punching step of the polarizing plate, since the stress generated in the protective film A due to the insertion of the knife blade is smaller than the stress generated in the protective film B, the adjustment of the load of the rubber particles a applied to the protective film A is not appropriate. The protective film B is so necessary. Moreover, when the tensile elastic modulus of the protective film A is relatively low, the "stress caused by the tip of the blade" or the "stress generated by pressing the protective film A" on the protective film B can also be reduced. Specifically, the tensile elastic modulus of the protective film A at 25° C. is preferably 1.6 to 2.6 GPa.

保護膜A之拉伸彈性模數可依據JIS K7127測定。具體而言，可藉以下順序測定。 1) 將保護膜A切成1cm(TD方向)×10cm(MD方向)作成試料片，於25℃60%RH之環境下調濕24小時。 2) 藉由JIS K7127記載之拉伸試驗方法測定所得試料片之拉伸彈性模數。亦即，將試料片設定於拉伸試驗裝置ORIENTIC公司製TENSILON上，測定以夾具間距離50.0mm、拉伸速度50mm/min之條件進行拉伸試驗時之拉伸彈性模數。測定係於25℃、60%RH下進行。The tensile elastic modulus of the protective film A can be measured in accordance with JIS K7127. Specifically, it can be measured by the following procedure. 1) Cut the protective film A into 1cm (TD direction)×10cm (MD direction) to make a sample piece, and adjust the humidity for 24 hours in an environment of 25°C and 60%RH. 2) Measure the tensile elastic modulus of the obtained sample piece by the tensile test method described in JIS K7127. That is, the sample piece was set on a tensile testing device TENSILON manufactured by ORIENTIC, and the tensile modulus of elasticity when the tensile test was performed under the conditions of a distance between clamps of 50.0 mm and a tensile speed of 50 mm/min was measured. The measurement is performed at 25°C and 60%RH.

保護膜A之拉伸彈性模數可藉由(甲基)丙烯酸系樹脂之組成或橡膠粒子a之含量及組成等而調整。基於減低保護膜A之拉伸彈性模數之觀點，較佳減少(甲基)丙烯酸系樹脂之源自含有環之單體的構造單位之比例，或增多橡膠粒子a之含量，或減少橡膠粒子a之源自苯乙烯類之構造單位之含量。The tensile elastic modulus of the protective film A can be adjusted by the composition of the (meth)acrylic resin or the content and composition of the rubber particles a. From the viewpoint of reducing the tensile elastic modulus of the protective film A, it is better to reduce the ratio of the structural units derived from the monomer containing the ring of the (meth)acrylic resin, or to increase the content of rubber particles a, or to reduce the rubber particles a is the content of structural units derived from styrene.

(濁度) 保護膜A較佳係透明性高。保護膜A之濁度較佳為2.0%以下，更佳為1.0%以下。濁度可藉由將試料40mm×80nm於25℃、60%RH下，以濁度儀(HGM-2DP，SUGA試驗機)依據JIS K-6714測定。(Turbidity) The protective film A preferably has high transparency. The haze of the protective film A is preferably 2.0% or less, more preferably 1.0% or less. The turbidity can be measured with a turbidity meter (HGM-2DP, SUGA testing machine) in accordance with JIS K-6714 by placing a sample of 40mm×80nm at 25°C and 60%RH.

(厚度) 保護膜A之厚度並未特別限定，但較佳比保護膜B的厚度厚。保護膜A之厚度相對較厚時，由於保護膜A之鋼性提高，故於偏光板之衝打步驟中，抽出刀刃之際，不僅是保護膜A，偏光板全體之變形亦容易減少。具體而言，保護膜A之厚度較佳為40~100μm，更佳為50~ 80μm。(thickness) The thickness of the protective film A is not particularly limited, but it is preferably thicker than the thickness of the protective film B. When the thickness of the protective film A is relatively thick, the rigidity of the protective film A is improved, so when the blade is drawn out in the punching step of the polarizing plate, not only the protective film A but also the overall deformation of the polarizing plate is easily reduced. Specifically, the thickness of the protective film A is preferably 40 to 100 μm, more preferably 50 to 80 μm.

1-3. 保護膜B 保護膜B，於作成顯示裝置時，係設置於偏光器與液晶胞等之顯示元件之間作為相位差膜發揮功能。保護膜B包含(甲基)丙烯酸系樹脂與橡膠粒子b。1-3. Protective film B The protective film B is provided between a polarizer and a display element such as a liquid crystal cell and functions as a retardation film when making a display device. The protective film B contains (meth)acrylic resin and rubber particles b.

1-3-1. (甲基)丙烯酸系樹脂 保護膜B所含之(甲基)丙烯酸系樹脂係包含源自甲基丙烯酸甲酯之構造單位(U1)、源自苯基馬來醯亞胺之構造單位(U2)與源自丙烯酸烷酯之構造單位(U3)之共聚物。1-3-1. (Meth) acrylic resin The (meth)acrylic resin contained in the protective film B includes a structural unit derived from methyl methacrylate (U1), a structural unit derived from phenylmaleimide (U2), and alkyl acrylate The structural unit (U3) of the copolymer.

源自甲基丙烯酸甲酯之構造單位(U1)之含量，相對於構成(甲基)丙烯酸系樹脂之全構造單位，較佳為50~95質量%，更佳為70~90質量%。The content of the structural unit (U1) derived from methyl methacrylate is preferably 50-95% by mass, more preferably 70-90% by mass relative to the total structural unit constituting the (meth)acrylic resin.

源自苯基馬來醯亞胺之構造單位(U2)由於具有平面性高的構造，且具有適度極性。藉此對於衝打時產生之膜面內之變形，藉由該構造與橡膠粒子之相互作用，容易抑制於橡膠粒子與樹脂間產生空隙。其結果，可抑制(甲基)丙烯酸系樹脂與橡膠粒子之界面剝離，藉此可抑制保護膜B與接著劑層之層間剝離。The structural unit (U2) derived from phenylmaleimide has a highly planar structure and has moderate polarity. This makes it easy to suppress the generation of voids between the rubber particles and the resin due to the interaction between the structure and the rubber particles in response to the deformation in the film surface generated during punching. As a result, it is possible to suppress the peeling of the interface between the (meth)acrylic resin and the rubber particles, and thereby it is possible to suppress the peeling between the protective film B and the adhesive layer.

源自苯基馬來醯亞胺之構造單位(U2)之含量，相對於構成(甲基)丙烯酸系樹脂之全構造單位，較佳為1~25質量%。源自苯基馬來醯亞胺之構造單位(U2)之含量若為1質量%以上，則容易抑制橡膠粒子b與(甲基)丙烯酸系樹脂之界面剝離，藉此容易抑制保護膜B與接著劑層之層間剝離。源自苯基馬來醯亞胺之構造單位(U2)之含量若為25質量%以下，則不易損及保護膜B之脆性。基於上述觀點，源自苯基馬來醯亞胺之構造單位(U2)之含量更佳為7~15質量%。The content of the structural unit (U2) derived from the phenylmaleimide is preferably 1 to 25% by mass relative to the total structural unit constituting the (meth)acrylic resin. If the content of the structural unit (U2) derived from phenylmaleimide is 1% by mass or more, it is easy to suppress the peeling of the interface between the rubber particles b and the (meth)acrylic resin, thereby easily suppressing the protective film B and the Then the interlayer peeling of the agent layer. If the content of the structural unit (U2) derived from phenylmaleimide is 25% by mass or less, the brittleness of the protective film B will not be easily damaged. Based on the above point of view, the content of the structural unit (U2) derived from phenylmaleimide is more preferably 7-15% by mass.

源自丙烯酸烷酯之構造單位(U3)可抑制(甲基)丙烯酸系樹脂與橡膠粒子b之界面剝離。具體而言，如後述般構成橡膠粒子b之殼部之聚合物(b2)具有源自丙烯酸丁酯等之丙烯酸酯之構造單位的情況下，源自丙烯酸烷酯之構造單位(U3)由於與源自丙烯酸酯之構造單位之親和性提高，故提高(甲基)丙烯酸系樹脂與橡膠粒子b之親和性。藉此，於偏光板之衝打性中，可抑制(甲基)丙烯酸系樹脂與橡膠粒子之界面剝離，藉此抑制保護膜B與接著劑層之層間密著性降低。丙烯酸烷酯較佳係烷基部分的碳原子數為1~7，較佳1~5之丙烯酸烷酯。丙烯酸烷酯之例包含丙烯酸甲酯、丙烯酸乙酯、丙烯酸丙酯、丙烯酸丁酯、丙烯酸2-羥基乙酯、丙烯酸己酯、丙烯酸2-乙基己酯等。The structural unit (U3) derived from alkyl acrylate can suppress the peeling of the interface between the (meth)acrylic resin and the rubber particles b. Specifically, when the polymer (b2) constituting the shell of the rubber particle b has a structural unit derived from acrylate such as butyl acrylate as described later, the structural unit (U3) derived from alkyl acrylate is due to The affinity of the structural unit derived from acrylate is improved, so the affinity between the (meth)acrylic resin and the rubber particles b is improved. Thereby, in the punchability of the polarizing plate, it is possible to suppress the peeling of the interface between the (meth)acrylic resin and the rubber particles, thereby suppressing the decrease in the interlayer adhesion between the protective film B and the adhesive layer. The alkyl acrylate is preferably an alkyl acrylate having 1 to 7, preferably 1 to 5 carbon atoms in the alkyl moiety. Examples of alkyl acrylates include methyl acrylate, ethyl acrylate, propyl acrylate, butyl acrylate, 2-hydroxyethyl acrylate, hexyl acrylate, 2-ethylhexyl acrylate, and the like.

源自丙烯酸烷酯之構造單位(U3)之含量，相對於構成(甲基)丙烯酸系樹脂之全構造單位，較佳為1~25質量%。源自丙烯酸烷酯之構造單位(U3)之含量若為1質量%以上，則容易抑制(甲基)丙烯酸系樹脂與橡膠粒子之界面剝離，若為25質量%以下，則不易損及耐熱性。基於上述觀點，源自丙烯酸烷酯之構造單位之含量更佳為5~15質量%。The content of the structural unit (U3) derived from the alkyl acrylate is preferably 1 to 25% by mass relative to the total structural unit constituting the (meth)acrylic resin. If the content of the structural unit (U3) derived from alkyl acrylate is 1% by mass or more, it is easy to inhibit the peeling of the interface between the (meth)acrylic resin and the rubber particles, and if it is 25% by mass or less, it is not easy to impair heat resistance . Based on the above point of view, the content of structural units derived from alkyl acrylate is more preferably 5 to 15% by mass.

源自苯基馬來醯亞胺之構造單位(U2)相對於源自苯基馬來醯亞胺之構造單位(U2)與源自丙烯酸烷酯之構造單位(U3)之合計量之比率，較佳為20~70質量%。該比率若為20質量%以上，則容易提高保護膜B之耐熱性或適度提高拉伸彈性模數，容易充分抑制橡膠粒子b與樹脂之界面剝離或因此所致之保護膜B與接著劑層之層間剝離，若為70質量%以下，則保護膜B不會過脆。The ratio of the structural unit (U2) derived from phenylmaleimines to the total amount of the structural unit (U2) derived from phenylmaleimines and the structural unit (U3) derived from alkyl acrylate, Preferably it is 20-70 mass %. If the ratio is 20% by mass or more, it is easy to improve the heat resistance of the protective film B or to increase the tensile elastic modulus appropriately, and it is easy to sufficiently suppress the peeling of the rubber particles b and the resin interface or the protective film B and the adhesive layer caused by this If the interlayer peeling is less than 70% by mass, the protective film B will not be too brittle.

(甲基)丙烯酸系樹脂根據需要亦可進而包含源自上述以外之其他單體之構造單位。此等其他單體之例包含與作為保護膜A所使用之構成(甲基)丙烯酸系樹脂之共聚合單體所舉例者相同者。The (meth)acrylic resin may further include structural units derived from other monomers other than the above as needed. Examples of these other monomers include the same as those exemplified for the copolymerized monomer constituting the (meth)acrylic resin used as the protective film A.

(甲基)丙烯酸系樹脂之玻璃轉移溫度(Tg)較佳為105℃以上，更佳為110~150℃。(甲基)丙烯酸系樹脂之Tg若為上述範圍，則不僅容易提高保護膜B之耐熱性，亦容易提高澆鑄製膜時之乾燥效率。為了提高(甲基)丙烯酸系樹脂之Tg，例如較佳使源自苯基馬來醯亞胺之構造單位(U2)或源自丙烯酸烷酯之構造單位(U3)之含量適度增多。The glass transition temperature (Tg) of the (meth)acrylic resin is preferably 105°C or higher, more preferably 110 to 150°C. If the Tg of the (meth)acrylic resin is in the above range, not only the heat resistance of the protective film B can be easily improved, but also the drying efficiency at the time of casting the film can be easily improved. In order to increase the Tg of the (meth)acrylic resin, for example, it is preferable to appropriately increase the content of the structural unit (U2) derived from phenylmaleimide or the structural unit (U3) derived from alkyl acrylate.

(甲基)丙烯酸系樹脂之重量平均分子量(Mw)較佳為50萬~300萬。(甲基)丙烯酸系樹脂之重量平均分子量若為上述範圍，則可對膜賦予充分機械強度(韌性)。基於上述觀點，(甲基)丙烯酸系樹脂之重量平均分子量更佳為60萬~200萬。The weight average molecular weight (Mw) of the (meth)acrylic resin is preferably 500,000 to 3 million. If the weight average molecular weight of the (meth)acrylic resin is in the above range, sufficient mechanical strength (toughness) can be imparted to the film. Based on the above point of view, the weight average molecular weight of the (meth)acrylic resin is more preferably 600,000 to 2 million.

(甲基)丙烯酸系樹脂之含量，相對於保護膜B，較佳為60質量%以上，更佳為70質量%以上。The content of the (meth)acrylic resin relative to the protective film B is preferably 60% by mass or more, and more preferably 70% by mass or more.

1-3-2. 橡膠粒子b 保護膜B中所含之橡膠粒子b，與前述同樣，可對保護膜B賦予韌性。1-3-2. Rubber particles b The rubber particles b contained in the protective film B can impart toughness to the protective film B in the same manner as described above.

保護膜B之沿厚度方向之剖面中，橡膠粒子b之平均縱橫比較佳為1.2~3.0。橡膠粒子b之平均縱橫比若為1.2以上，則於偏光板之衝打步驟中，橡膠粒子b容易追隨刀刃押入時之保護膜B之變形。因此可緩和保護膜B所受到之應力，而抑制偏光板衝打時之龜裂。橡膠粒子b之平均縱橫比若為3.0以下，則不易產生橡膠粒子b與(甲基)丙烯酸系樹脂之界面剝離。亦即，橡膠粒子b之平均縱橫比若過高，則因橡膠粒子b延伸所致之殘留應力亦變大，故(甲基)丙烯酸系樹脂之塑性變形與橡膠粒子b之塑性變形容易產生偏差，於(甲基)丙烯酸系樹脂與橡膠粒子b之界面容易產生空隙。橡膠粒子b之平均縱橫比若為3.0以下，則由於可減小因此等延伸所致之殘留應力，故不易產生橡膠粒子b與(甲基)丙烯酸系樹脂之界面剝離。藉此，於偏光板之衝打步驟中，抽出所押入之刀刃之際，可抑制接著劑層與保護膜B之層間剝離。基於同樣觀點，橡膠粒子b之平均縱橫比更佳為1.5~2.9。In the cross section of the protective film B along the thickness direction, the average aspect ratio of the rubber particles b is preferably 1.2 to 3.0. If the average aspect ratio of the rubber particles b is 1.2 or more, the rubber particles b will easily follow the deformation of the protective film B when the blade is pushed in during the punching step of the polarizing plate. Therefore, the stress on the protective film B can be alleviated, and the cracking of the polarizing plate during punching can be suppressed. If the average aspect ratio of the rubber particles b is 3.0 or less, the interface peeling between the rubber particles b and the (meth)acrylic resin is unlikely to occur. That is, if the average aspect ratio of the rubber particles b is too high, the residual stress due to the extension of the rubber particles b will also increase, so the plastic deformation of the (meth)acrylic resin and the plastic deformation of the rubber particles b are likely to deviate , Voids are easily generated at the interface between the (meth)acrylic resin and the rubber particles b. If the average aspect ratio of the rubber particles b is 3.0 or less, the residual stress caused by the equal elongation can be reduced, so that the interface peeling between the rubber particles b and the (meth)acrylic resin is unlikely to occur. Thereby, when the inserted blade is withdrawn in the punching step of the polarizing plate, the interlayer peeling of the adhesive layer and the protective film B can be suppressed. Based on the same viewpoint, the average aspect ratio of the rubber particles b is more preferably 1.5 to 2.9.

橡膠粒子b之平均長徑較佳為250~400nm。橡膠粒子a之平均長徑若為250nm以上，則不僅對保護膜B賦予充分韌性或柔軟性，亦容易獲得使應力緩和之效果。橡膠粒子a之平均長徑若為400nm以下，則不易損及將應力分散之效果。橡膠粒子b之平均長徑係橡膠粒子之長徑平均值。The average long diameter of the rubber particles b is preferably 250 to 400 nm. If the average major axis of the rubber particles a is 250 nm or more, not only will sufficient toughness or flexibility be imparted to the protective film B, but the effect of alleviating stress will also be easily obtained. If the average long diameter of the rubber particles a is 400 nm or less, the effect of dispersing stress is not easily impaired. The average long diameter of the rubber particles b is the average long diameter of the rubber particles.

橡膠粒子b之平均縱橫比與橡膠粒子a之平均縱橫比同樣定義，且可以相同方法測定。橡膠粒子b之平均長徑亦與橡膠粒子a之平均長徑同樣定義且可以相同方法測定。The average aspect ratio of the rubber particles b is defined in the same way as the average aspect ratio of the rubber particles a, and can be measured in the same way. The average long diameter of the rubber particles b is also defined in the same way as the average long diameter of the rubber particles a and can be measured in the same way.

橡膠粒子b之平均縱橫比及平均長徑與前述同樣，可藉由保護膜B之延伸條件而調整。為了增大橡膠粒子b之平均縱橫比時，例如較佳提高保護膜B之至膜時之延伸倍率。且，為了增大橡膠粒子b之平均長徑時，較佳例如使用平均粒徑較大之橡膠粒子作為原料，或提高延伸倍率。The average aspect ratio and average long diameter of the rubber particles b are the same as described above, and can be adjusted by the extension conditions of the protective film B. In order to increase the average aspect ratio of the rubber particles b, for example, it is preferable to increase the stretching ratio of the protective film B to the film. In order to increase the average long diameter of the rubber particles b, it is preferable to use rubber particles with a larger average particle size as a raw material, or to increase the elongation ratio.

構成橡膠粒子b之單體成分及構造與構成橡膠粒子a之單體成分及構造相同。例如橡膠粒子b係具有包含丙烯酸系橡膠狀聚合物(b1)之芯部與包含源自甲基丙烯酸酯之構造單位之聚合物(b2)之殼部之芯殼型粒子。丙烯酸系橡膠狀聚合物(b1)與丙烯酸系橡膠狀聚合物(a1)相同，組成可相同亦可不同。聚合物(b2)與聚合物(a2)相同，組成可相同亦可不同。The monomer component and structure constituting the rubber particle b are the same as the monomer component and structure constituting the rubber particle a. For example, the rubber particle b is a core-shell type particle having a core containing an acrylic rubber-like polymer (b1) and a shell containing a polymer (b2) derived from a structural unit of methacrylate. The acrylic rubber-like polymer (b1) is the same as the acrylic rubber-like polymer (a1), and the composition may be the same or different. The polymer (b2) is the same as the polymer (a2), and the composition may be the same or different.

構成橡膠粒子b之丙烯酸系橡膠狀聚合物(b1)包含源自苯乙烯類之構造單位時，保護膜B中所含之橡膠粒子b之源自苯乙烯類之構造單位含量較佳多於保護膜A中所含之橡膠粒子a之源自苯乙烯類之構造單位含量。亦即丙烯酸系橡膠狀聚合物(b1)之源自苯乙烯類之構造單位含量較佳多於丙烯酸系橡膠狀聚合物(a1)之源自苯乙烯類之構造單位含量。具體而言，橡膠粒子b之源自苯乙烯類之構造單位含量，相對於構成丙烯酸系橡膠狀聚合物(b1)之全部構成單位，較佳為5~60質量%，更佳為40~60質量%。源自苯乙烯類之構造單位含量越多，通常橡膠粒子b之硬度變越高。源自苯乙烯類之構造單位含量若為上述範圍內，則由於橡膠粒子b適當變硬，容易將拉伸彈性模數調整於上述範圍內。When the acrylic rubber-like polymer (b1) constituting the rubber particles b contains styrene-derived structural units, the content of the styrene-derived structural units of the rubber particles b contained in the protective film B is preferably more than that of the protection The content of styrene-derived structural units of the rubber particles a contained in the film A. That is, the content of the styrene-derived structural unit of the acrylic rubber-like polymer (b1) is preferably greater than the content of the styrene-derived structural unit of the acrylic rubber-like polymer (a1). Specifically, the content of the styrene-derived structural unit of the rubber particles b is preferably 5-60% by mass, more preferably 40-60% by mass relative to all the structural units constituting the acrylic rubber-like polymer (b1) quality%. The higher the content of styrene-derived structural units, the higher the hardness of the rubber particles b generally becomes. If the content of the styrene-derived structural unit is within the above range, the rubber particles b will be appropriately hardened, making it easy to adjust the tensile modulus of elasticity within the above range.

橡膠粒子b之玻璃轉移溫度，與前述相同，較佳為室溫(25℃)以下。且橡膠粒子b之玻璃轉移溫度較佳高於橡膠粒子a之玻璃轉移溫度。The glass transition temperature of the rubber particles b is the same as described above, and is preferably room temperature (25°C) or lower. Moreover, the glass transition temperature of the rubber particles b is preferably higher than the glass transition temperature of the rubber particles a.

保護膜B中所含之橡膠粒子b之含量並未特別限定，但基於使保護膜B之拉伸彈性模數高於保護膜A之觀點等，較佳少於保護膜A中所含之橡膠粒子a之含量。具體而言，保護膜B中所含之橡膠粒子b之含量相對於保護膜B較佳為2~15質量%，更佳為5~12質量%。The content of the rubber particles b contained in the protective film B is not particularly limited, but based on the viewpoint that the tensile elastic modulus of the protective film B is higher than that of the protective film A, etc., it is preferably less than the rubber contained in the protective film A The content of particle a. Specifically, the content of the rubber particles b contained in the protective film B is preferably 2 to 15% by mass relative to the protective film B, and more preferably 5 to 12% by mass.

1-3-3. 其他成分 保護膜B亦可根據需要含有上述以外之其他成分。其他成分可使用與保護膜A中之其他成分相同者。1-3-3. Other ingredients The protective film B may contain components other than the above as needed. The other components can be the same as the other components in the protective film A.

1-3-4. 物性 (拉伸彈性模數) 保護膜B之拉伸彈性模數並未特別限定，但基於容易抑制衝打偏光板之際的龜裂或層間剝離之觀點，較佳高於保護膜A之拉伸彈性模數。其原因係偏光板之衝打步驟中，因刀刃押入而於保護膜B產生之應力大於於保護膜A產生之應力，故調整施加至保護膜B中之橡膠粒子b之負荷的必要性較高之故。亦即，橡膠粒子b周圍若為柔軟的樹脂，則來自刀刃所承受之力容易被樹脂分散，相對地，橡膠粒子b的周圍若為硬的樹脂，則來自刀刃所承受之力不會過於被樹脂發散，橡膠粒子b容易承受力。亦即，藉由使保護膜B之拉伸彈性模數適當提高，容易對橡膠粒子b施加適度負荷，故偏光板衝打時施加之應力容易被橡膠粒子b吸收，容易抑制於樹脂產生龜裂。藉此，可容易抑制衝打偏光板之際的龜裂或層間剝離。保護膜B與保護膜A於25℃下之拉伸彈性模數之差為例如0.3GPa以上。保護膜B於25℃下之拉伸彈性模數較佳為2.4~3.4GPa。保護膜B之拉伸彈性模數可藉與前述相同方法測定。1-3-4. Physical properties (Tensile modulus of elasticity) The tensile elastic modulus of the protective film B is not particularly limited, but it is preferably higher than the tensile elastic modulus of the protective film A from the viewpoint of easily suppressing cracking or interlayer peeling when punching a polarizing plate. The reason is that in the punching step of the polarizing plate, the stress generated in the protective film B due to the insertion of the blade is greater than the stress generated in the protective film A, so it is necessary to adjust the load applied to the rubber particles b in the protective film B For this reason. That is, if the rubber particles b are surrounded by soft resin, the force from the blade is easily dispersed by the resin. On the other hand, if the rubber particles b are surrounded by hard resin, the force from the blade will not be too much. The resin diverges, and the rubber particles b can easily bear the force. That is, by appropriately increasing the tensile elastic modulus of the protective film B, it is easy to apply a moderate load to the rubber particles b. Therefore, the stress applied when the polarizing plate is punched is easily absorbed by the rubber particles b, and it is easy to suppress cracks in the resin. . Thereby, it is possible to easily suppress cracks or delamination during punching of the polarizing plate. The difference between the tensile elastic modulus of the protective film B and the protective film A at 25° C. is, for example, 0.3 GPa or more. The tensile elastic modulus of the protective film B at 25° C. is preferably 2.4 to 3.4 GPa. The tensile elastic modulus of the protective film B can be measured by the same method as described above.

保護膜B之拉伸彈性模數可藉由(甲基)丙烯酸系樹脂之組成或橡膠粒子b之含量及組成等而調整。基於提高保護膜B之拉伸彈性模數之觀點，(甲基)丙烯酸系樹脂之較佳提高源自苯基馬來醯亞胺之構造單位(U2)/(源自苯基馬來醯亞胺之構造單位(U2)與源自丙烯酸烷酯之構造單位(U3)之合計)之比例，或減少橡膠粒子b之含量，或增多橡膠粒子b之源自苯乙烯類之構造單位之含量。The tensile elastic modulus of the protective film B can be adjusted by the composition of the (meth)acrylic resin or the content and composition of the rubber particles b. Based on the viewpoint of increasing the tensile modulus of the protective film B, the (meth)acrylic resin is better to improve the structural unit (U2)/(derived from phenylmaleimines) The ratio of the amine structural unit (U2) to the total structural unit (U3) derived from alkyl acrylate (U3)), or reduce the content of rubber particles b, or increase the content of rubber particles b of styrene-derived structural units.

(濁度) 保護膜B之濁度與前述同樣，較佳為2.0%以下，更佳為1.0%以下。(Turbidity) The haze of the protective film B is the same as described above, and is preferably 2.0% or less, more preferably 1.0% or less.

(相位差Ro及Rt) 基於保護膜B使用作為例如IPS模式用的相位差膜之觀點，以測定波長550nm、23℃、55%RH之環境下測定之面內方向之相位差Ro較佳為0~10nm，更佳為0~5nm。保護膜B之厚度方向之相位差Rt較佳為-20~20nm，更佳為-10~ 10nm。(Phase difference Ro and Rt) Based on the viewpoint that the protective film B is used as a retardation film for the IPS mode, for example, the retardation Ro in the in-plane direction measured in an environment with a measurement wavelength of 550nm, 23°C, and 55%RH is preferably 0-10nm, more preferably 0~5nm. The retardation Rt in the thickness direction of the protective film B is preferably -20 to 20 nm, more preferably -10 to 10 nm.

Ro及Rt分別以下述式定義。 式(2a)：Ro=(nx-ny)×d 式(2b)：Rt=((nx+ny)/2-nz)×d (式中， nx表示膜之面內慢軸方向(折射率為最大之方向)之折射率， ny表示膜之與面內慢軸正交方向之折射率， nz表示膜之厚度方向之折射率， d表示膜厚度(nm))。Ro and Rt are each defined by the following formula. Formula (2a): Ro=(nx-ny)×d Formula (2b): Rt=((nx+ny)/2-nz)×d (In the formula, nx represents the refractive index of the film in the slow axis direction (the direction where the refractive index is the maximum), ny represents the refractive index of the film in the direction orthogonal to the in-plane slow axis, nz represents the refractive index in the thickness direction of the film, d represents the film thickness (nm)).

保護膜B之面內慢軸可藉由自動折射率計Axo Scan(Axo Scan Mueller Matrix Polarimeter：Axo Matrix公司製)確認。The in-plane slow axis of the protective film B can be confirmed with an automatic refractometer Axo Scan (Axo Scan Mueller Matrix Polarimeter: manufactured by Axo Matrix).

Ro及Rt之測定可藉以下方法進行。 1) 使保護膜於23℃55%RH之環境下調濕24小時。以阿貝折射計測定該膜之平均折射率，使用市售之側徑儀(Micrometer)測定厚度d。 2) 調濕後之膜於測定波長550nm下之延遲Ro及Rt分別使用自動折射率計Axo Scan(Axo Scan Mueller Matrix Polarimeter：Axo Matrix公司製)，於23℃55%RH之環境下測定。Ro and Rt can be measured by the following method. 1) Adjust the humidity of the protective film at 23°C and 55%RH for 24 hours. The average refractive index of the film was measured with an Abbe refractometer, and the thickness d was measured with a commercially available side diameter meter (Micrometer). 2) The retardation Ro and Rt of the humidity-controlled film at a measurement wavelength of 550nm were measured using an automatic refractometer Axo Scan (Axo Scan Mueller Matrix Polarimeter: manufactured by Axo Matrix) at 23°C and 55% RH.

保護膜B之相位差Ro及Rt可藉由例如(甲基)丙烯酸系樹脂之單體組成或延伸條件而調整。為了減低保護膜B之相位差Ro及Rt時，較佳使用不易因延伸產生相位差之(甲基)丙烯酸系樹脂(例如將源自具有負的雙折射之單體之構造單位與源自具有正的雙折射之單體之構造單位設為相位差可抵銷之單體比率)。The retardation Ro and Rt of the protective film B can be adjusted by, for example, the monomer composition of (meth)acrylic resin or the stretching conditions. In order to reduce the retardation Ro and Rt of the protective film B, it is preferable to use a (meth)acrylic resin that is not easy to produce retardation due to extension (for example, a structural unit derived from a monomer having a negative birefringence and a structural unit derived from a monomer having a negative birefringence The structural unit of the positive birefringent monomer is set to the monomer ratio that can be offset by the phase difference).

(殘留溶劑量) 保護膜B由於較佳以澆鑄法製膜，故進而含有殘留溶劑。殘留溶劑量相對於保護膜B較佳為700ppm以下，更佳為30~700ppm。殘留溶劑之含量，可藉由保護膜之製造步驟中澆鑄至支撐體上之摻雜物乾燥條件而調整。(Amount of residual solvent) Since the protective film B is preferably formed by a casting method, it further contains a residual solvent. The amount of residual solvent relative to the protective film B is preferably 700 ppm or less, more preferably 30 to 700 ppm. The content of the residual solvent can be adjusted by the drying conditions of the dopant cast on the support in the manufacturing step of the protective film.

保護膜B之殘留溶劑量可藉由頂空氣體層析法(head space gas chromatography)測定。頂空氣體層析法係將試料封入容器中並加熱，以於容器中充滿揮發成分之狀態快速將容器中之氣體注入氣體層析儀，邊進行質量分析並進行化合物之鑑定邊進行揮發成分之定量者。頂空法可藉由氣體層析觀測揮發成分之全部波峰，同時利用磁氣相互作用之分析法，亦可一併以高精度進行揮發性物質或單體等之定量。The amount of residual solvent in the protective film B can be determined by head space gas chromatography. The headspace gas chromatography method is to seal the sample in a container and heat it, and quickly inject the gas in the container into the gas chromatograph in the state of being full of volatile components, and carry out mass analysis and identification of the compound while carrying out the determination of the volatile component. Quantifier. The headspace method can observe all the peaks of volatile components by gas chromatography, and at the same time use the analysis method of magnetic interaction, and can also quantify volatile substances or monomers with high precision.

(厚度) 保護膜B厚度並未特別限定，但較佳薄於保護膜A之厚度。保護膜B厚度相對較薄時，於偏光板之衝打步驟中，抽出刀刃之際，不僅不容易卡住刀刃，於刀刃押入時之物理性變形亦少。藉此，進一步抑制衝打偏光板之際的龜裂。例如保護膜B厚度設為相對於保護膜A厚度之20~ 77%。具體而言，保護膜B厚度較佳為10~60μm，更佳為10 ~40μm。(thickness) The thickness of the protective film B is not particularly limited, but it is preferably thinner than the thickness of the protective film A. When the thickness of the protective film B is relatively thin, in the punching step of the polarizing plate, when the blade is drawn out, not only is it not easy to jam the blade, but there is also less physical deformation when the blade is pushed in. This further suppresses cracks when the polarizing plate is punched. For example, the thickness of the protective film B is set to be 20 to 77% relative to the thickness of the protective film A. Specifically, the thickness of the protective film B is preferably 10 to 60 μm, more preferably 10 to 40 μm.

1-3-5. 保護膜A及B之製造方法 保護膜A及B宜以任意方法製造，可藉溶液澆鑄方式(澆鑄法)製造，亦可藉熔融澆鑄方式(熔融)製造。1-3-5. Manufacturing method of protective film A and B The protective films A and B are preferably manufactured by any method, and can be manufactured by solution casting (casting method) or by melt casting (melting).

保護膜A係以例如熔融澆鑄方式(熔融)製造。熔融澆鑄方式(熔融)經過下述步驟可獲得保護膜：將包含(甲基)丙烯酸系樹脂與橡膠粒子之樹脂組成物熔融擠出之步驟，將擠出之樹脂組成物冷卻固化之步驟，及根據需要使冷卻固化所得之膜狀物延伸之步驟。製造保護膜A之際之延伸倍率並未特別限定，但基於使橡膠粒子a之平均縱橫比小於橡膠粒子b之觀點，較佳比製造保護膜B時之延伸倍率低，例如為10%以下，更佳未延伸。The protective film A is produced by, for example, a melt casting method (melting). Melt casting method (melting) to obtain a protective film through the following steps: a step of melting and extruding a resin composition containing (meth)acrylic resin and rubber particles, a step of cooling and solidifying the extruded resin composition, and The step of stretching the film obtained by cooling and solidifying as required. The stretch magnification when manufacturing the protective film A is not particularly limited, but from the viewpoint of making the average aspect ratio of the rubber particles a smaller than that of the rubber particles b, it is preferably lower than the stretch magnification when manufacturing the protective film B, for example, 10% or less. Better unextended.

基於可使用之材料限制較少之觀點，保護膜B較佳以澆鑄法製造。亦即，保護膜A係至少經過下述步驟而製造：1)獲得包含前述之(甲基)丙烯酸系樹脂、橡膠粒子及溶劑之摻雜物的步驟，2)將所得摻雜物澆鑄於支撐體上後，乾燥及剝離，獲得膜狀物之步驟，3)使所得膜狀物根據需要邊延伸邊乾燥之步驟。From the viewpoint that there are fewer restrictions on the materials that can be used, the protective film B is preferably manufactured by a casting method. That is, the protective film A is manufactured through at least the following steps: 1) the step of obtaining the dopant containing the aforementioned (meth)acrylic resin, rubber particles and solvent, and 2) casting the obtained dopant on the support After the body is applied, it is dried and peeled to obtain a film, and 3) the film is stretched and dried as needed.

關於1)之步驟 將(甲基)丙烯酸系樹脂與橡膠粒子a或b(以下亦總稱為「橡膠粒子」)溶解或分散於溶劑中而調製摻雜物。About the steps of 1) The (meth)acrylic resin and rubber particles a or b (hereinafter also collectively referred to as "rubber particles") are dissolved or dispersed in a solvent to prepare a dopant.

摻雜物所用之溶劑包含至少使(甲基)丙烯酸系樹脂溶解之有機溶劑(良溶劑)。良溶劑之例包含二氯甲烷等之氯系有機溶劑；或乙酸甲酯、乙酸乙酯、丙酮、四氫呋喃等之非氯系有機溶劑。其中較佳為二氯甲烷。The solvent used for the dopant includes an organic solvent (good solvent) that at least dissolves the (meth)acrylic resin. Examples of good solvents include chlorine-based organic solvents such as dichloromethane; or non-chlorine-based organic solvents such as methyl acetate, ethyl acetate, acetone, and tetrahydrofuran. Among them, dichloromethane is preferred.

摻雜物所用之溶劑亦可進而包含弱溶劑。弱溶劑之例包含碳原子數1~4之直鏈或分支鏈狀之脂肪族醇。摻雜物中之醇的比例變高時，膜狀物容易凝膠化，容易使自金屬支撐體之剝離變容易。作為碳原子數1~4之直鏈或分支鏈狀之脂肪族醇可舉例為甲醇、乙醇、正丙醇、異丙醇、正丁醇、第二丁醇、第三丁醇。該等中，乙醇由於摻雜物之安定性、沸點亦較低，乾燥性亦良好故而較佳。The solvent used for the dopant may further include a weak solvent. Examples of weak solvents include linear or branched aliphatic alcohols with 1 to 4 carbon atoms. When the ratio of alcohol in the dopant becomes higher, the membrane is likely to be gelled, and it is easy to easily peel off from the metal support. Examples of linear or branched aliphatic alcohols having 1 to 4 carbon atoms include methanol, ethanol, n-propanol, isopropanol, n-butanol, sec-butanol, and t-butanol. Among them, ethanol is better because of its stability, lower boiling point, and good drying properties.

關於2)之步驟 所得摻雜物澆鑄於支撐體上。摻雜物之澆鑄可自澆鑄模嘴噴出而進行。About the steps of 2) The obtained dopant is cast on the support. The casting of the dopant can be carried out by spraying from the casting die nozzle.

其次，使澆鑄於支撐體上之摻雜物中之溶劑蒸發、乾燥。將經乾燥之摻雜物自支撐體剝離，獲得膜狀物。Secondly, the solvent in the dopant cast on the support is evaporated and dried. The dried dopant is peeled off from the support to obtain a membrane.

自支撐體剝離之際的摻雜物殘留溶劑量(剝離時之膜狀物之殘留溶劑量)較佳為例如25質量%以上，更佳為30~37質量%。剝離時之殘留溶劑量若為37質量%以下，則容易抑制膜狀物因剝離而過度伸長。The residual solvent amount of the dopant when peeling from the support (the residual solvent amount of the film during peeling) is preferably, for example, 25% by mass or more, and more preferably 30 to 37% by mass. If the residual solvent amount at the time of peeling is 37% by mass or less, it is easy to suppress excessive elongation of the film material due to peeling.

剝離時之摻雜物殘留溶劑量係以下述式定義。以下亦相同。 摻雜物之殘留溶劑量(質量%)=(摻雜物加熱處理前質量-摻雜物加熱處理後質量)/摻雜物加熱處理後質量×100 又，測定殘留溶劑量之際的加熱處理係指140℃、30分鐘之加熱處理。The residual solvent amount of the dopant at the time of peeling is defined by the following formula. The following is also the same. The amount of residual solvent of the adulterant (mass%) = (the mass of the adulterant before heating treatment-the mass of the adulterant after heating treatment) / the mass of adulterant after heating treatment × 100 In addition, the heat treatment when measuring the amount of residual solvent refers to a heat treatment at 140°C for 30 minutes.

剝離時之殘留溶劑量可藉由支撐體上之摻雜物乾燥溫度或乾燥時間、支撐體之溫度等而調整。The amount of residual solvent during peeling can be adjusted by the drying temperature or drying time of the dopant on the support, the temperature of the support, and so on.

關於3)之步驟 使所得膜狀物乾燥。乾燥可以一階段進行，亦可多階段進行。且乾燥亦可根據需要邊延伸邊進行。About the steps of 3) The resulting film is dried. Drying can be carried out in one stage or in multiple stages. And drying can also be carried out while stretching as needed.

例如膜狀物之乾燥步驟亦可包含使膜狀物預備乾燥之步驟(預備乾燥步驟)、使膜狀物延伸之步驟(延伸步驟)及使延伸後之膜狀物乾燥之步驟(正式乾燥步驟)。For example, the drying step of the film may also include the step of pre-drying the film (preparatory drying step), the step of stretching the film (stretching step), and the step of drying the stretched film (formal drying step) ).

(預備乾燥步驟) 預備乾燥溫度(延伸前之乾燥溫度)係比延伸溫度高的溫度。具體而言，於將(甲基)丙烯酸系樹脂之玻璃轉移溫度設為Tg時，較佳為Tg(℃)以上，更佳為(Tg+10)~(Tg+50)℃。預備乾燥溫度若為Tg(℃)以上，較佳為(Tg+10)℃以上，則由於溶劑容易適度揮發，故易提高搬送性(處理性)，若為(Tg+50)℃以下，則由於溶劑不會過度揮發，故不易損及隨後延伸步驟之延伸性。初期乾燥溫度於(a)以拉幅機延伸機或滾筒邊搬送邊以非接觸加熱型乾燥之情況，係測定為延伸機內溫度或熱風溫度等之環境溫度。(Preparatory drying step) The preliminary drying temperature (drying temperature before stretching) is a temperature higher than the stretching temperature. Specifically, when the glass transition temperature of the (meth)acrylic resin is Tg, it is preferably Tg (°C) or higher, and more preferably (Tg+10) to (Tg+50)°C. If the pre-drying temperature is Tg (°C) or higher, preferably (Tg+10)°C or higher, the solvent is likely to volatilize moderately, so it is easy to improve the transportability (handling), if it is (Tg+50)°C or lower, then Since the solvent does not evaporate excessively, it is not easy to impair the extensibility of the subsequent extension step. The initial drying temperature in (a) the case of non-contact heating type drying while being conveyed by a tenter stretcher or drum, is measured as the ambient temperature such as the temperature in the stretcher or the temperature of hot air.

(延伸步驟) 延伸只要對應於所要求之光學特性進行即可，較佳至少於一方向延伸，亦可於互相正交之兩方向延伸(例如膜狀物之寬度方向(TD方向)與和其正交之搬送方向(MD方向)之雙軸延伸)。(Extension step) The extension can be performed in accordance with the required optical characteristics, preferably in at least one direction, or in two directions orthogonal to each other (for example, the width direction of the film (TD direction) and the conveyance orthogonal to it. Direction (MD direction) biaxial extension).

基於容易將保護膜B所含之橡膠粒子b之平均縱橫比調整於上述範圍之觀點，製造保護膜B之際的延伸倍率較佳高於製造保護膜A之際的延伸倍率。具體而言，製造保護膜B之際的延伸倍率較佳為40~100%，更佳為60~ 100%。雙軸延伸之情況，各方向之延伸倍率較佳均為上述範圍內。From the viewpoint that it is easy to adjust the average aspect ratio of the rubber particles b contained in the protective film B within the above-mentioned range, the stretch magnification when the protective film B is manufactured is preferably higher than the stretch magnification when the protective film A is manufactured. Specifically, the stretching ratio at the time of manufacturing the protective film B is preferably 40 to 100%, and more preferably 60 to 100%. In the case of biaxial stretching, the stretching magnification in each direction is preferably within the above-mentioned range.

延伸倍率(%)定義為(延伸後之膜延伸方向大小-延伸前之膜延伸方向大小)/(延伸前之膜延伸方向大小)×100。又，進行雙軸延伸之情況，較佳TD方向與MD方向均設為上述延伸倍率。Stretching magnification (%) is defined as (size in the extension direction of the film after extension-size in the extension direction of the film before extension)/(size in the extension direction of the film before extension)×100. In the case of biaxial stretching, it is preferable that both the TD direction and the MD direction be set to the above-mentioned stretching magnification.

延伸溫度(延伸時之乾燥溫度)與前述同樣，於將(甲基)丙烯酸系樹脂之玻璃轉移溫度設為Tg時，較佳為Tg(℃)以上，更佳為(Tg+10)℃~(Tg+50)℃。延伸溫度若為Tg(℃)以上，較佳(Tg+10)℃以上，則由於溶劑容易適度揮發，故容易將延伸張力調整適當範圍，若為(Tg+50)℃以下，則由於溶劑不會過度揮發，故不易損及延伸性。保護膜B之製造時的延伸溫度設為例如115℃以上。延伸溫度與前述同樣，較佳測定(a)延伸機內溫度等之環境溫度。The stretching temperature (drying temperature during stretching) is the same as described above. When the glass transition temperature of the (meth)acrylic resin is set to Tg, it is preferably Tg(°C) or higher, more preferably (Tg+10)°C~ (Tg+50)°C. If the stretching temperature is Tg(℃) or higher, preferably (Tg+10)°C or higher, since the solvent is likely to volatilize moderately, it is easy to adjust the stretching tension to an appropriate range. If it is (Tg+50)°C or less, the solvent will not Will be excessively volatilized, so it is not easy to damage and extensibility. The stretching temperature at the time of manufacturing the protective film B is set to 115°C or higher, for example. The stretching temperature is the same as described above, and it is preferable to measure (a) the ambient temperature such as the temperature in the stretching machine.

延伸開始時之膜狀物中之殘留溶劑量較佳與剝離時之膜狀物中殘留溶劑量相同程度，較佳為例如20~ 30質量%，更佳為25~30質量%。The amount of residual solvent in the film at the start of stretching is preferably the same as the amount of residual solvent in the film at the time of peeling, and is preferably, for example, 20-30% by mass, more preferably 25-30% by mass.

膜狀物之TD方向(寬度方向)之延伸可藉由例如以夾具或銷固定膜狀物之兩端，於行進方向擴展夾具或銷的間隔之方法(拉幅法)進行。膜狀物之MD方向的延伸可藉由例如使複數輥產生周速差，於其間利用輥周速差之方法(輥法)進行。The extension of the film in the TD direction (width direction) can be performed by, for example, fixing the two ends of the film with clamps or pins, and expanding the interval between the clamps or pins in the traveling direction (tentering method). The stretching of the film in the MD direction can be performed by, for example, generating a difference in peripheral speed of a plurality of rollers, and using the difference in the peripheral speed of the rollers (roll method).

(正式乾燥步驟) 基於更減低殘留溶劑量之觀點，較佳使延伸後所得之膜狀物進一步乾燥。例如較佳使延伸後所得之膜狀物邊以輥等搬送邊進一步乾燥。(Formal drying step) From the viewpoint of further reducing the amount of residual solvent, it is preferable to further dry the film obtained after stretching. For example, it is preferable to further dry the film obtained after stretching while being conveyed by a roller or the like.

正式乾燥溫度(未延伸之情況為乾燥溫度)，於將(甲基)丙烯酸系樹脂之玻璃轉移溫度設為Tg時，較佳為(Tg-50)~(Tg-30)℃，更佳為(Tg-40)~(Tg-30)℃。後乾燥溫度若為(Tg-50)℃以上，則溶劑容易自延伸後之膜狀物充分揮發去除，若為(Tg-30)℃以下，則可高度抑制膜狀物之變形等。正式乾燥溫度與前述同樣，較佳測定(a)熱風溫度等之環境溫度。The official drying temperature (drying temperature when it is not stretched), when the glass transition temperature of the (meth)acrylic resin is set to Tg, it is preferably (Tg-50)~(Tg-30)°C, more preferably (Tg-40)~(Tg-30)℃. If the post-drying temperature is above (Tg-50)°C, the solvent will easily be fully volatilized and removed from the stretched film. If it is below (Tg-30)°C, the deformation of the film can be highly suppressed. The actual drying temperature is the same as described above, and it is preferable to measure the ambient temperature such as (a) hot air temperature.

1-4. 接著劑層A及B 接著劑層A係配置於保護膜A與偏光器之間，將該等予以接著。同樣，接著劑層B係配置於保護膜B與偏光器之間，將該等予以接著。1-4. Adhesive layer A and B The adhesive layer A is arranged between the protective film A and the polarizer, and these are adhered. Similarly, the adhesive layer B is arranged between the protective film B and the polarizer, and these are bonded.

接著劑層A及B可為由完全皂化型聚乙烯醇水溶液(水糊)所得之層，亦可為活性能量線硬化性接著劑之硬化物層。基於與包含(甲基)丙烯酸系樹脂之保護膜A及B之親和性高，容易良好接著之觀點，接著劑層A及B較佳為活性能量線硬化性接著劑之硬化物層。Adhesive layers A and B may be layers obtained from a fully saponified polyvinyl alcohol aqueous solution (water paste), or may be hardened layers of active energy ray-curable adhesives. From the viewpoint of high affinity with the protective films A and B containing (meth)acrylic resin and easy adhesion, the adhesive layers A and B are preferably cured layers of active energy ray-curable adhesives.

活性能量線硬化性接著劑可為光自由基聚合性組成物，亦可為光陽離子聚合性組成物。其中，較佳為光陽離子聚合性組成物。The active energy ray curable adhesive may be a photo-radical polymerizable composition or a photo-cationically polymerizable composition. Among them, a photocationically polymerizable composition is preferred.

光陽離子聚合性組成物包含環氧系化合物與光陽離子性聚合起始劑。The photocationic polymerizable composition contains an epoxy-based compound and a photocationic polymerization initiator.

環氧系化合物係分子內具有1個以上，較佳2個以上環氧基之化合物。環氧系化合物之例包含對脂環式多元醇反應表氯醇所得之氫化環氧系化合物(具有脂環式環之多元醇之縮水甘油醚)；脂肪族多元醇或其環氧烷加成物之聚縮水甘油醚等之脂肪族環氧系化合物；分子內具有1個以上鍵結於脂環式環之環氧基之脂環式環氧系化合物。環氧系化合物可僅使用1種，亦可併用2種以上。The epoxy compound is a compound having one or more, preferably two or more epoxy groups in the molecule. Examples of epoxy compounds include hydrogenated epoxy compounds obtained by reacting epichlorohydrin to alicyclic polyols (glycidyl ethers of alicyclic ring polyols); aliphatic polyols or their alkylene oxide additions Aliphatic epoxy compounds such as polyglycidyl ether; alicyclic epoxy compounds with more than one epoxy group bonded to the alicyclic ring in the molecule. The epoxy compound may use only 1 type, and may use 2 or more types together.

光陽離子性聚合起始劑為例如芳香族重氮鎓鹽；芳香族碘鎓鹽或芳香族鋶鹽等之鎓鹽；鐵-芳香烴錯合物等。The photocationic polymerization initiator is, for example, an aromatic diazonium salt; an onium salt such as an aromatic iodonium salt or an aromatic sulfonium salt; an iron-aromatic hydrocarbon complex and the like.

光陽離子性聚合起始劑可根據需要進而含有氧雜環丁烷、多元醇等之陽離子聚合促進劑、光增感劑、離子捕捉劑、抗氧化劑、鏈轉移劑、黏著賦予劑、熱塑性樹脂、填充劑、流動調整劑、可塑劑、消泡劑、抗靜電劑、調平劑、溶劑等之添加劑。The photocationic polymerization initiator may further contain cationic polymerization accelerators such as oxetane and polyols, photosensitizers, ion scavengers, antioxidants, chain transfer agents, adhesion imparting agents, thermoplastic resins, Additives such as fillers, flow regulators, plasticizers, defoamers, antistatic agents, leveling agents, solvents, etc.

接著劑層A及B之厚度並未特別限定，但可為例如0.01~10μm，較佳為0.01~5μm左右。The thickness of the adhesive layers A and B is not particularly limited, but may be, for example, 0.01 to 10 μm, preferably about 0.01 to 5 μm.

1-5. 黏著劑層 黏著劑層係配置於偏光板之保護膜B之與偏光器相反側之面。本發明之偏光板係經由該黏著劑層與液晶胞等之顯示元件貼合。1-5. Adhesive layer The adhesive layer is arranged on the surface of the protective film B of the polarizer on the opposite side of the polarizer. The polarizing plate of the present invention is bonded to display elements such as liquid crystal cells via the adhesive layer.

構成黏著劑層之黏著劑並未特別限定，可為例如丙烯酸系黏著劑、矽氧系黏著劑、橡膠系黏著劑等。基於透明性、耐候性、耐熱性、加工性之觀點，較佳為丙烯酸系黏著劑。The adhesive constituting the adhesive layer is not particularly limited, and may be, for example, acrylic adhesive, silicone adhesive, rubber adhesive, and the like. From the viewpoints of transparency, weather resistance, heat resistance, and processability, an acrylic adhesive is preferred.

黏著劑亦可根據需要進而包含黏著賦予劑、可塑劑、玻璃纖維、玻璃珠、金屬粉、其他填充劑、顏料、著色劑、填充劑、抗氧化劑、紫外線吸收劑、矽烷偶合劑等之各種添加劑。The adhesive may further contain various additives such as adhesive agent, plasticizer, glass fiber, glass beads, metal powder, other fillers, pigments, coloring agents, fillers, antioxidants, ultraviolet absorbers, silane coupling agents, etc. .

黏著劑層之厚度通常為3~100μm左右，較佳為5~50μm。The thickness of the adhesive layer is usually about 3-100 μm, preferably 5-50 μm.

黏著劑層之表面係經施以脫模處理之剝離膜予以保護。剝離膜之例包含丙烯酸系膜、聚碳酸酯膜、聚酯膜、氟樹脂膜等之塑膠膜。The surface of the adhesive layer is protected by a release film applied with mold release treatment. Examples of the release film include plastic films such as acrylic films, polycarbonate films, polyester films, and fluororesin films.

2. 偏光板之製造方法 本發明之偏光板可經由下述步驟而獲得：1)於偏光器之一面經由接著劑層合、貼合保護膜A之步驟，2)於偏光器之另一面經由接著劑層合、貼合保護膜B之步驟，3)於貼合之層合物的保護膜B上貼附黏著劑層及保護膜，獲得偏光板之步驟。以下以使用活性能量線硬化性接著劑作為接著劑之例加以說明。2. Manufacturing method of polarizing plate The polarizing plate of the present invention can be obtained through the following steps: 1) Laminating and bonding the protective film A on one side of the polarizer through an adhesive, 2) Laminating and bonding through the adhesive on the other side of the polarizer The step of protective film B, 3) the step of sticking an adhesive layer and a protective film on the protective film B of the laminated laminate to obtain a polarizing plate. The following describes an example of using an active energy ray curable adhesive as the adhesive.

關於1)之步驟 於保護膜A之表面根據需要實施電暈處理等之表面處理。其次，於偏光器之另一面，經由活性能量線硬化性接著劑之層，層合保護膜A(經表面處理時，以保護膜A之表面處理面成為偏光器側之方式)後，照射活性能量線，使活性能量線硬化性接著劑硬化。藉此，經由活性能量線硬化性接著劑之硬化物層將偏光器與保護膜A接著並貼合。About the steps of 1) Perform surface treatment such as corona treatment on the surface of the protective film A as needed. Secondly, on the other side of the polarizer, through the active energy ray curable adhesive layer, laminate the protective film A (when surface treatment, the surface treatment surface of the protective film A becomes the polarizer side), and then irradiate the active The energy ray hardens the active energy ray curable adhesive. Thereby, the polarizer and the protective film A are bonded and bonded via the cured material layer of the active energy ray curable adhesive.

關於2)之步驟 同樣，於保護膜B之表面根據需要實施電暈處理等之表面處理。其次，於偏光器之另一面，經由活性能量線硬化性接著劑之層，層合保護膜B(經表面處理時，以保護膜B之表面處理面成為偏光器側之方式)後，照射活性能量線，使活性能量線硬化性接著劑硬化。藉此，經由活性能量線硬化性接著劑之硬化物層將偏光器與保護膜B接著並貼合。About the steps of 2) Similarly, the surface of the protective film B is subjected to surface treatment such as corona treatment as necessary. Secondly, on the other side of the polarizer, through the active energy ray curable adhesive layer, laminate the protective film B (when surface treatment, the surface treatment surface of the protective film B becomes the polarizer side), and then irradiate the active The energy ray hardens the active energy ray curable adhesive. Thereby, the polarizer and the protective film B are bonded and bonded via the cured material layer of the active energy ray curable adhesive.

1)之步驟與2)之步驟可同時進行，亦可逐次進行。基於提高製造效率之觀點，較佳1)之步驟與2)之步驟同時進行。Steps 1) and 2) can be carried out simultaneously or successively. From the viewpoint of improving manufacturing efficiency, it is preferable that the step 1) and the step 2) be performed at the same time.

1)之步驟與2)之步驟同時進行時，保護膜A、偏光器及保護膜B之層合較佳以輥對輥方式進行。接著，對所得之層合物照射活性能量線，使活性能量線硬化性接著劑硬化即可。When the step 1) and the step 2) are performed simultaneously, the lamination of the protective film A, the polarizer, and the protective film B is preferably carried out in a roll-to-roll manner. Then, the obtained laminate is irradiated with active energy rays to harden the active energy ray curable adhesive.

關於3)之步驟 其次，於所得偏光板之保護膜B上，進一步貼附黏著劑層及其剝離膜。具體而言，藉由於保護膜B上轉印設置有黏著劑層之剝離膜等之方法，可形成黏著劑層。About the steps of 3) Secondly, on the protective film B of the obtained polarizing plate, the adhesive layer and its release film are further attached. Specifically, the adhesive layer can be formed by a method such as transferring a release film provided with an adhesive layer on the protective film B.

所得之偏光板為長條狀之偏光板。長條狀偏光板捲取為捲筒狀，成為偏光板之捲筒體。接著，偏光板之捲筒體於使用時(例如製造顯示裝置時)捲出後，衝打成任意大小及形狀，供於製造顯示裝置。偏光板之衝打係藉由自保護膜A側押入刀刃而進行(參考圖2A)。The obtained polarizing plate is a long strip of polarizing plate. The long strip polarizer is rolled into a roll shape to become the roll body of the polarizer. Then, the roll body of the polarizing plate is rolled out during use (for example, when manufacturing a display device), and punched into any size and shape for use in manufacturing a display device. The punching of the polarizing plate is carried out by pushing the blade from the side of the protective film A (refer to Figure 2A).

3. 顯示裝置 本發明之顯示裝置包含本發明之偏光板。本發明之顯示裝置為液晶顯示裝置或有機EL顯示裝置等，較佳為液晶顯示裝置。3. Display device The display device of the present invention includes the polarizing plate of the present invention. The display device of the present invention is a liquid crystal display device or an organic EL display device, etc., preferably a liquid crystal display device.

亦即，本發明之液晶顯示裝置包含液晶胞、配置於液晶胞之一面之第一偏光板及配置於液晶胞之另一面之第二偏光板。That is, the liquid crystal display device of the present invention includes a liquid crystal cell, a first polarizing plate arranged on one side of the liquid crystal cell, and a second polarizing plate arranged on the other side of the liquid crystal cell.

液晶胞之顯示模式可為例如STN(超扭轉向列)、TN(扭轉向列)、OCB(光學補償彎曲)、HAN(混合對準向列)、VA(垂直對準、MVA(多域垂直對準)、PVA(經圖型化垂直對準))、IPS(平面內切換)等。例如於攜帶機器用途之液晶顯示裝置較佳為IPS模式。The display mode of the liquid crystal cell can be, for example, STN (Super Twisted Nematic), TN (Twisted Nematic), OCB (Optical Compensation Bend), HAN (Hybrid Alignment Nematic), VA (Vertical Alignment, MVA (Multi-domain Vertical) Alignment), PVA (patterned vertical alignment)), IPS (in-plane switching), etc. For example, a liquid crystal display device used for portable equipment is preferably an IPS mode.

第一偏光板與第二偏光板之一者或兩者為本發明之偏光板。本發明之偏光板係配置為使黏著劑層與液晶胞密著。 [實施例]Either or both of the first polarizing plate and the second polarizing plate are the polarizing plates of the present invention. The polarizing plate of the present invention is configured to make the adhesive layer and the liquid crystal cell close. [Example]

以下藉由實施例具體說明本發明，但本發明並非限定於此。Hereinafter, the present invention will be described in detail with examples, but the present invention is not limited thereto.

1. 保護膜之材料 (1) (甲基)丙烯酸系樹脂 準備表1中所示之(甲基)丙烯酸系樹脂1~9。

Figure 02_image001
1. Material of the protective film (1) (Meth) acrylic resin Prepare the (meth) acrylic resins 1 to 9 shown in Table 1.
Figure 02_image001

(甲基)丙烯酸系樹脂1~9之玻璃轉移溫度及重量平均分子量係藉以下方法測定。The glass transition temperature and weight average molecular weight of (meth)acrylic resins 1 to 9 are measured by the following method.

(玻璃轉移溫度) (甲基)丙烯酸系樹脂之玻璃轉移溫度(Tg)係使用DSC (Differential Scanning Calorimetry：示差掃描熱量計)，依據JIS K7121-2012測定。(Glass transition temperature) The glass transition temperature (Tg) of the (meth)acrylic resin is measured in accordance with JIS K7121-2012 using DSC (Differential Scanning Calorimetry).

(重量平均分子量) (甲基)丙烯酸系樹脂之重量平均分子量(Mw)可使用凝膠滲透層析(TOSOH公司製HLC8220GPC)、管柱(TOSOH公司製TSK-GEL G6000HXL-G5000HXL-G5000HXL-G4000HXL-G3000HXL串聯)而測定。將試料20mg±0.5mg溶解於四氫呋10ml中，以0.45mm之過濾器過濾。該溶液100ml注入管柱(溫度40℃)，以檢測器RI溫度40℃下測定，使用聚苯乙烯換算值。(Weight average molecular weight) The weight average molecular weight (Mw) of the (meth)acrylic resin can be measured using gel permeation chromatography (TOSOH HLC8220GPC), column (TOSOH TSK-GEL G6000HXL-G5000HXL-G5000HXL-G4000HXL-G3000HXL in series) . Dissolve 20 mg ± 0.5 mg of the sample in 10 ml of tetrahydrofuran, and filter with a 0.45 mm filter. 100 ml of this solution was injected into a column (temperature 40°C), and measured at a detector RI temperature of 40°C, using a polystyrene conversion value.

(2)橡膠粒子 ＜橡膠粒子R1之調製＞ 於附攪拌機之8L聚合裝置中饋入以下化合物。 去離子水：175重量份 聚氧乙烯月桂基醚磷酸：0.104質量份 硼酸：0.4725質量份 碳酸鈉：0.04725質量份(2) Rubber particles ＜Preparation of rubber particles R1＞ The following compounds were fed into an 8L polymerization device with a stirrer. Deionized water: 175 parts by weight Polyoxyethylene lauryl ether phosphoric acid: 0.104 parts by mass Boric acid: 0.4725 parts by mass Sodium carbonate: 0.04725 parts by mass

將聚合機內以氮氣充分置換後，內溫設為80℃，於聚合機內一次追加由單體混合物(1-1) 27質量份(甲基丙烯酸甲酯70.9質量%、丙烯酸丁酯12.5質量%、苯乙烯16.6質量%之混合物)及甲基丙烯酸烯丙酯0.135質量份所成之混合物之26質量%，隨後，追加次硫酸甲醛鈉0.0645質量份、乙二胺四乙酸2鈉0.0056質量份、硫酸亞鐵0.0014質量份、第三丁基過氧化氫0.0207質量份，其15分鐘後，追加第三丁基過氧化氫0.0345質量份，進而繼續聚合15分鐘。 其次，以2質量%水溶液之形態直接追加氫氧化鈉0.0098質量份及聚氧乙烯月桂基醚磷酸0.0852質量份，歷時60分鐘連續添加上述混合物之剩餘74質量%。添加結束30分鐘後，追加第三丁基過氧化氫0.069質量份，進而繼續聚合30分鐘，獲得聚合物。After fully replacing the inside of the polymerization machine with nitrogen, the internal temperature was set to 80°C, and 27 parts by mass of the monomer mixture (1-1) (70.9% by mass of methyl methacrylate, 12.5% by mass of butyl acrylate) were added in the polymerization machine at a time. %, a mixture of 16.6% by mass of styrene) and 26% by mass of a mixture of 0.135 parts by mass of allyl methacrylate, followed by the addition of 0.0645 parts by mass of sodium formaldehyde sulfoxylate and 0.0056 parts by mass of 2 sodium ethylenediaminetetraacetic acid , 0.0014 parts by mass of ferrous sulfate and 0.0207 parts by mass of tertiary butyl hydroperoxide. After 15 minutes, 0.0345 parts by mass of tertiary butyl hydroperoxide was added, and the polymerization was continued for 15 minutes. Next, 0.0098 parts by mass of sodium hydroxide and 0.0852 parts by mass of polyoxyethylene lauryl ether phosphoric acid were directly added in the form of a 2% by mass aqueous solution, and the remaining 74% by mass of the above mixture was continuously added over 60 minutes. After 30 minutes from the end of the addition, 0.069 parts by mass of tertiary butyl hydroperoxide was added, and the polymerization was continued for 30 minutes to obtain a polymer.

隨後，以2質量%水溶液之形態添加氫氧化鈉0.0267質量份及以2質量%水溶液之形態添加過硫酸鉀0.08質量份，其次，歷時150分鐘連續添加單體混合物(1-2)(丙烯酸丁酯47.0質量%與苯乙烯53.0質量%)50質量份及甲基丙烯酸烯丙酯0.75質量份所成之混合物。添加結束後，以2質量%水溶液之形態添加過硫酸鉀0.015質量份，繼續聚合120分鐘，獲得丙烯酸系橡膠狀聚合物。源自苯乙烯之構成單位相對於構成所得丙烯酸系橡膠狀聚合物之全部構成單位(單體混合物(1-1)與(1-2)之合計)之含量(質量%)為40質量%。Subsequently, 0.0267 parts by mass of sodium hydroxide was added in the form of a 2% by mass aqueous solution and 0.08 parts by mass of potassium persulfate was added in the form of a 2% by mass aqueous solution. Next, the monomer mixture (1-2) (butyl acrylate) was continuously added over 150 minutes. A mixture of 47.0% by mass of ester, 53.0% by mass of styrene), 50 parts by mass, and 0.75 parts by mass of allyl methacrylate. After the addition, 0.015 parts by mass of potassium persulfate was added in the form of a 2% by mass aqueous solution, and the polymerization was continued for 120 minutes to obtain an acrylic rubber-like polymer. The content (mass %) of the styrene-derived structural unit with respect to all the structural units (the total of the monomer mixture (1-1) and (1-2)) constituting the obtained acrylic rubber-like polymer was 40% by mass.

隨後，以2質量%水溶液之形態添加過硫酸鉀0.023質量份，歷時45分鐘連續添加單體混合物(2-1) 15質量份(甲基丙烯酸甲酯95質量%、丙烯酸丁酯5質量%)，進而繼續聚合30分鐘。Subsequently, 0.023 parts by mass of potassium persulfate was added in the form of a 2% by mass aqueous solution, and 15 parts by mass of the monomer mixture (2-1) (95% by mass of methyl methacrylate and 5% by mass of butyl acrylate) were continuously added over 45 minutes. , And continue polymerization for 30 minutes.

隨後，歷時25分鐘連續添加單體混合物(2-2) 8質量份(甲基丙烯酸甲酯52質量%、丙烯酸丁酯48質量%)，進而繼續聚合60分鐘，藉此獲得接枝共聚物乳膠。Subsequently, 8 parts by mass of the monomer mixture (2-2) (52% by mass of methyl methacrylate and 48% by mass of butyl acrylate) were continuously added for 25 minutes, and the polymerization was continued for 60 minutes, thereby obtaining a graft copolymer latex .

所得乳膠以氯化鎂鹽析，進行凝固、水洗、乾燥，獲得白色粉末狀接枝共聚物(橡膠粒子R1)。橡膠粒子R1之接枝率為24.2%，苯乙烯量為40質量%，玻璃轉移溫度(Tg)為5℃，平均粒徑為200nm。The obtained latex was salted out with magnesium chloride, coagulated, washed with water, and dried to obtain a white powdery graft copolymer (rubber particles R1). The grafting rate of the rubber particles R1 is 24.2%, the amount of styrene is 40% by mass, the glass transition temperature (Tg) is 5°C, and the average particle size is 200 nm.

＜橡膠粒子R2~R5之調製＞ 將源自苯乙烯之構成單位相對於構成丙烯酸系橡膠狀聚合物之全部構成單位之含量(質量%)成為表2所示之值之方式，變更單體混合物(1-1)與(1-2)之單體組成以外，與橡膠粒子R1同樣，獲得接枝共聚物(橡膠粒子)。＜Preparation of rubber particles R2~R5＞ The content (mass%) of the styrene-derived structural unit relative to all the structural units constituting the acrylic rubber-like polymer was changed to the value shown in Table 2, and the monomer mixtures (1-1) and (1- 2) Except for the monomer composition, the graft copolymer (rubber particles) was obtained in the same manner as the rubber particles R1.

橡膠粒子R1~R5之構成示於表2。

Figure 02_image003
The composition of rubber particles R1 to R5 is shown in Table 2.
Figure 02_image003

橡膠粒子R1~R5之平均粒徑係藉以下方法測定。The average particle size of rubber particles R1~R5 is measured by the following method.

(平均粒徑) 以ζ(zeta)電位・粒徑測定系統(大塚電子股份有限公司製ELSZ-2000ZS)測定所得分散液中之橡膠粒子之分散粒徑。(The average particle size) The ζ (zeta) potential and particle size measurement system (ELSZ-2000ZS manufactured by Otsuka Electronics Co., Ltd.) was used to measure the dispersed particle size of the rubber particles in the resulting dispersion.

(苯乙烯量) 橡膠粒子之源自苯乙烯類之構造單位含量可藉由前述熱分解GC/MS檢測出之波峰面積比而算出之方法測定。又，GCMS之測定條件如以下。 測定裝置：SHIMAZU GCMS QP2010 管柱種類：Urtra Alloy-5(尺寸30m×徑0.25mm) 載體氣體種類：He 流量條件：1.8mL/分鐘 管柱烘箱溫度條件：40℃-10℃/分鐘-320℃ 介面溫度：300℃ 離子源溫度：200℃ 檢測模式：SIM(靶離子：m/z104，確認離子：m/z78)(Amount of styrene) The styrene-derived structural unit content of the rubber particles can be measured by the method of calculating the peak area ratio detected by the thermal decomposition GC/MS. In addition, the measurement conditions of GCMS are as follows. Measuring device: SHIMAZU GCMS QP2010 Column type: Ultra Alloy-5 (size 30m×diameter 0.25mm) Carrier gas type: He Flow conditions: 1.8mL/min Column oven temperature conditions: 40℃-10℃/min-320℃ Interface temperature: 300℃ Ion source temperature: 200℃ Detection mode: SIM (target ion: m/z104, confirmation ion: m/z78)

2. 保護膜之製作 2-1. 保護膜A之製作 (保護膜101之製作) (甲基)丙烯酸系樹脂1的顆粒與橡膠粒子R1以乾燥機於80℃乾燥4小時後，供給至φ65mm單軸擠出機。於擠出機出口以使樹脂溫度成為270℃之方式加熱熔融，自T模嘴擠出熔融樹脂。T模嘴出口之剛噴出後之樹脂溫度為270℃。噴出之熔融樹脂以調整至70℃之澆鑄輥與調整至70℃之接觸輥予以夾持，冷卻固化。隨後，所得膜之兩端連續切開後，以拉取輥邊拉取邊捲取，獲得厚度55μm之保護膜101。2. Production of protective film 2-1. Production of protective film A (Making of protective film 101) After the pellets of (meth)acrylic resin 1 and rubber particles R1 were dried at 80°C for 4 hours in a dryer, they were supplied to a φ65 mm uniaxial extruder. Heat and melt the resin at the exit of the extruder so that the resin temperature becomes 270°C, and extrude the molten resin from the T-die nozzle. The resin temperature at the exit of the T die nozzle just after spraying is 270°C. The sprayed molten resin is clamped by a casting roll adjusted to 70°C and a touch roller adjusted to 70°C, and cooled and solidified. Subsequently, after the two ends of the obtained film were continuously cut, they were taken up by a take-up roll to obtain a protective film 101 with a thickness of 55 μm.

＜保護膜102之製作＞ 除了冷卻固化後所得之膜以表3所示之條件延伸以外，與保護膜101同樣獲得保護膜102。＜Production of protective film 102＞ The protective film 102 was obtained in the same manner as the protective film 101 except that the film obtained after cooling and solidification was stretched under the conditions shown in Table 3.

＜保護膜103之製作＞ 除了未添加橡膠粒子R1且以表3所示之條件延伸以外，與保護膜101同樣獲得保護膜103。＜Making of protective film 103＞ The protective film 103 was obtained in the same manner as the protective film 101 except that the rubber particles R1 were not added and extended under the conditions shown in Table 3.

＜保護膜104之製作＞ (橡膠粒子分散液之調製) 11.3質量份之橡膠粒子R2與200質量份之二氯甲烷以溶解器攪拌混合50分鐘後，使用多模嘴分散機(大平洋機工股份有限公司製)於1500rpm之條件下分散，獲得橡膠粒子分散液。＜Production of protective film 104＞ (Preparation of rubber particle dispersion) 11.3 parts by mass of rubber particles R2 and 200 parts by mass of dichloromethane were stirred and mixed with a dissolver for 50 minutes, and then dispersed using a multi-nozzle disperser (manufactured by Taiheiyo Machinery Co., Ltd.) at 1500 rpm to obtain rubber particle dispersion liquid.

(摻雜物之調製) 其次，調製下述組成之摻雜物(dope)。首先，於加壓溶解槽中添加二氯甲烷及乙醇。其次，於加壓溶解槽中邊攪拌邊投入(甲基)丙烯酸系樹脂2。其次，投入上述調製之橡膠粒子分散液，邊將其攪拌使之完全溶解。使用ROKI TECHNO(股)製之SHP150將其過濾，獲得摻雜物。 (甲基)丙烯酸系樹脂2：100質量份 二氯甲烷：200質量份 乙醇：100質量份 橡膠粒子分散液：500質量份(Modulation of adulterants) Next, a dope of the following composition is prepared. First, add dichloromethane and ethanol to the pressurized dissolution tank. Next, the (meth)acrylic resin 2 is put into the pressurized dissolution tank while stirring. Next, the rubber particle dispersion liquid prepared above is put into it, and it is stirred to completely dissolve it. Use ROKI TECHNO (stock) SHP150 to filter it to obtain adulterants. (Meth) acrylic resin 2: 100 parts by mass Dichloromethane: 200 parts by mass Ethanol: 100 parts by mass Rubber particle dispersion: 500 parts by mass

(製膜) 使用環狀帶澆鑄裝置，將摻雜物以溫度30℃、寬度1800mm均一澆鑄於不鏽鋼帶支撐體上。不鏽鋼帶之溫度控制於28℃。不鏽鋼帶之搬送速度設為20m/min。(Film making) Using an endless belt casting device, the dopant was uniformly cast on the stainless steel belt support at a temperature of 30°C and a width of 1800 mm. The temperature of the stainless steel strip is controlled at 28°C. The conveying speed of the stainless steel belt is set to 20m/min.

於不鏽鋼帶支撐體上，使溶劑蒸發至澆鑄(cast)的摻雜物中的殘留溶劑量成為30質量%。其次，以剝離張力128N/m，自不鏽鋼帶支撐體剝離，獲得膜狀物。亦即，剝離時之膜狀物殘留溶劑量為30質量%。經剝離之膜邊以多數滾筒搬送邊進一步乾燥，獲得膜厚55μm之保護膜104。On the stainless steel belt support, the amount of residual solvent in the cast dopant by evaporating the solvent to 30% by mass. Next, it was peeled from the stainless steel belt support with a peeling tension of 128 N/m to obtain a film. That is, the residual solvent amount of the film material at the time of peeling was 30% by mass. The peeled film was further dried while being transported by many rollers to obtain a protective film 104 with a film thickness of 55 μm.

＜保護膜105及106之製作＞ 除了將橡膠粒子R1含量變更為表3所示以外，與保護膜101同樣獲得保護膜105及106。＜Production of protective film 105 and 106＞ The protective films 105 and 106 were obtained in the same manner as the protective film 101 except that the content of the rubber particles R1 was changed to that shown in Table 3.

＜保護膜107及108之製作＞ 除了將保護膜厚度變更為表3所示之值般調整噴出量以外，與保護膜101同樣獲得保護膜107及108。＜Production of protective film 107 and 108＞ The protective films 107 and 108 were obtained in the same manner as the protective film 101 except that the thickness of the protective film was changed to the value shown in Table 3 to adjust the discharge amount.

＜評價＞ 藉以下方法測定所得保護膜101~108之橡膠粒子平均縱橫比及拉伸彈性模數。＜Evaluation＞ The average aspect ratio and tensile elastic modulus of the rubber particles of the obtained protective films 101 to 108 were measured by the following methods.

(平均縱橫比及平均長徑) 橡膠粒子之平均縱橫比及平均長徑可藉以下順序算出。 1) TEM觀察保護膜之沿厚度方向之剖面中，與保護膜之TD方向平行之剖面。觀察區域設為5μm×5μm。 2) 分別測定所得TEM圖像中各橡膠粒子之長徑、短徑，分別算出縱橫比。 3) 上述1)及2)之操作係改變觀察區域合計進行4處。接著，將所測定之縱橫比之平均值設為「平均縱橫比」，所測定之長徑之平均值設為「平均長徑」。(Average aspect ratio and average long diameter) The average aspect ratio and average long diameter of rubber particles can be calculated by the following procedure. 1) TEM observes the cross section of the protective film along the thickness direction, which is parallel to the TD direction of the protective film. The observation area is set to 5 μm×5 μm. 2) Measure the long diameter and short diameter of each rubber particle in the obtained TEM image, and calculate the aspect ratio. 3) The operations in 1) and 2) above are performed in 4 places in total to change the observation area. Next, the average value of the measured aspect ratio is set as the "average aspect ratio", and the average value of the measured long diameter is set as the "average long diameter".

(拉伸彈性模數) 將所得保護膜切成1cm(TD方向)×10cm(MD方向)作成試料片，於25℃60%RH之環境下調濕24小時。藉由JIS K7127記載之拉伸試驗方法測定所得試料片之拉伸彈性模數。具體而言，將試料片設定於拉伸試驗裝置ORIENTIC公司製TENSILON上，測定以夾具間距離50.0mm、拉伸速度50mm/min之條件進行拉伸試驗時之拉伸彈性模數。測定係於25℃、60%RH下進行。(Tensile modulus of elasticity) The obtained protective film was cut into 1 cm (TD direction)×10 cm (MD direction) to make sample pieces, and the humidity was adjusted for 24 hours under an environment of 25°C and 60%RH. The tensile modulus of the obtained sample piece was measured by the tensile test method described in JIS K7127. Specifically, the sample piece was set on a tensile testing device TENSILON manufactured by ORIENTIC, and the tensile modulus of elasticity when the tensile test was performed under the conditions of a distance between clamps of 50.0 mm and a tensile speed of 50 mm/min was measured. The measurement is performed at 25°C and 60%RH.

保護膜101~108之評價結果示於表3。又，表3中橡膠粒子含量表示相對於保護膜之量。表4及5亦相同。The evaluation results of the protective films 101 to 108 are shown in Table 3. In addition, the rubber particle content in Table 3 indicates the amount relative to the protective film. Tables 4 and 5 are also the same.

Figure 02_image005
Figure 02_image005

2-2. 保護膜B之製作 ＜保護膜201之製作＞ (橡膠粒子分散液之調製) 11質量份之橡膠粒子R3與200質量份之二氯甲烷以溶解器攪拌混合50分鐘後，使用多模嘴分散機(大平洋機工股份有限公司製)於1500rpm之條件下分散，獲得橡膠粒子分散液。2-2. Production of protective film B ＜Production of protective film 201＞ (Preparation of rubber particle dispersion) After 11 parts by mass of rubber particles R3 and 200 parts by mass of dichloromethane were stirred and mixed with a dissolver for 50 minutes, they were dispersed using a multi-nozzle disperser (manufactured by Taiheiyo Machinery Co., Ltd.) at 1500 rpm to obtain a rubber particle dispersion. liquid.

(摻雜物之調製) 其次，調製下述組成之摻雜物。首先，於加壓溶解槽中添加二氯甲烷及乙醇。其次，於加壓溶解槽中邊攪拌邊投入(甲基)丙烯酸系樹脂。其次，投入上述調製之橡膠粒子分散液，邊將其攪拌使之完全溶解。使用ROKI TECHNO (股)製之SHP150將其過濾，獲得摻雜物。 (甲基)丙烯酸系樹脂3：100質量份 二氯甲烷：400質量份 乙醇：90質量份 橡膠粒子分散液：220質量份(Modulation of adulterants) Next, prepare the dopant with the following composition. First, add dichloromethane and ethanol to the pressurized dissolution tank. Next, the (meth)acrylic resin is poured into the pressure dissolution tank while stirring. Next, the rubber particle dispersion liquid prepared above is put into it, and it is stirred to completely dissolve it. Use SHP150 manufactured by ROKI TECHNO (stock) to filter it to obtain adulterants. (Meth) acrylic resin 3: 100 parts by mass Dichloromethane: 400 parts by mass Ethanol: 90 parts by mass Rubber particle dispersion: 220 parts by mass

(製膜) 使用環狀帶澆鑄裝置，將摻雜物以溫度30℃、寬度1800mm均一澆鑄於不鏽鋼帶支撐體上。不鏽鋼帶之溫度控制於28℃。不鏽鋼帶之搬送速度設為20m/min。(Film making) Using an endless belt casting device, the dopant was uniformly cast on the stainless steel belt support at a temperature of 30°C and a width of 1800 mm. The temperature of the stainless steel strip is controlled at 28°C. The conveying speed of the stainless steel belt is set to 20m/min.

於不鏽鋼帶支撐體上，使溶劑蒸發至澆鑄(cast)的摻雜物中的殘留溶劑量成為30質量%。其次，以剝離張力128N/m，自不鏽鋼帶支撐體剝離，獲得膜狀物。亦即，剝離時之膜狀物殘留溶劑量為30質量%。On the stainless steel belt support, the amount of residual solvent in the cast dopant by evaporating the solvent to 30% by mass. Next, it was peeled from the stainless steel belt support with a peeling tension of 128 N/m to obtain a film. That is, the residual solvent amount of the film material at the time of peeling was 30% by mass.

其次，以多數滾筒搬送經剝離之膜，邊使所得膜狀物以拉幅機於60℃(Tg-60℃)之條件下於寬度方向(TD方向)延伸70%。隨後，邊以輥搬送邊於140℃(Tg+40℃)進一步乾燥，將以拉幅機夾具夾住之端部予以切開並捲取，獲得膜厚20μm之保護膜201。Secondly, the peeled film is transported by a plurality of rollers, and the obtained film is stretched 70% in the width direction (TD direction) under the condition of 60°C (Tg-60°C) with a tenter. Subsequently, it was further dried at 140°C (Tg+40°C) while being conveyed by a roller, and the end clamped by the tenter clamp was cut and wound to obtain a protective film 201 with a film thickness of 20 μm.

＜保護膜202~205之製作＞ 除了將延伸條件變更為表4所示以外，與保護膜201同樣獲得保護膜202~205。＜Making of protective film 202~205＞ Except that the stretching conditions were changed to those shown in Table 4, the protective films 202 to 205 were obtained in the same manner as the protective film 201.

＜保護膜206之製作＞ 除了未添加橡膠粒子R3且將延伸條件變更為表4所示以外，與保護膜201同樣獲得保護膜206。＜Production of protective film 206＞ The protective film 206 was obtained in the same manner as the protective film 201 except that the rubber particles R3 were not added and the stretching conditions were changed to those shown in Table 4.

＜保護膜207~212之製作＞ 除了將(甲基)丙烯酸系樹脂種類變更為表4所示以外，與保護膜201同樣獲得保護膜207~212。又，關於保護膜207，延伸條件亦變更如表4所示。＜Making of protective film 207~212＞ The protective films 207 to 212 were obtained in the same manner as in the protective film 201 except that the type of (meth)acrylic resin was changed to those shown in Table 4. In addition, regarding the protective film 207, the stretching conditions were also changed as shown in Table 4.

＜保護膜213、214之製作＞ 除了將橡膠粒子種類變更為表4所示以外，與保護膜201同樣獲得保護膜213、214。＜Production of protective film 213 and 214＞ The protective films 213 and 214 were obtained in the same manner as the protective film 201 except that the kind of rubber particles was changed to that shown in Table 4.

＜保護膜215及216之製作＞ 除了將所得保護膜厚度變更為表4所示之值般調整澆鑄量以外，與保護膜201同樣獲得保護膜215及216。＜Production of protective film 215 and 216＞ Except that the thickness of the obtained protective film was changed to the value shown in Table 4, the casting amount was adjusted, and the protective films 215 and 216 were obtained in the same manner as the protective film 201.

＜評價＞ 分別藉與前述同樣方法測定所得保護膜201~216之橡膠粒子平均縱橫比及拉伸彈性模數。保護膜201~216之評價結果示於表4。又，保護膜201所含之橡膠粒子之平均長徑為360nm。＜Evaluation＞ The average aspect ratio and tensile elastic modulus of the rubber particles of the obtained protective films 201 to 216 were measured by the same method as described above, respectively. The evaluation results of the protective films 201 to 216 are shown in Table 4. In addition, the average long diameter of the rubber particles contained in the protective film 201 is 360 nm.

Figure 02_image007
Figure 02_image007

3. 偏光板之製作與評價 ＜偏光板301之製作＞ (偏光器之製作) 將厚度25μm之聚乙烯醇系膜以35℃之水膨潤。所得膜於由碘0.075g、碘化鉀5g及水100g所成之水溶液中浸漬60秒，進而浸漬於由碘化鉀3g、硼酸7.5g及水100g所成之45℃之水溶液中。所得膜以延伸溫度55℃、延伸倍率5倍之條件進行單軸延伸。該單軸延伸膜經水洗後乾燥，獲得厚度12μm之偏光器。3. Production and evaluation of polarizing plate ＜Production of polarizing plate 301＞ (Making of Polarizer) The polyvinyl alcohol-based film with a thickness of 25 μm is swelled with water at 35°C. The obtained film was immersed in an aqueous solution of 0.075 g of iodine, 5 g of potassium iodide, and 100 g of water for 60 seconds, and then immersed in an aqueous solution of 3 g of potassium iodide, 7.5 g of boric acid, and 100 g of water at 45°C. The obtained film was uniaxially stretched under the conditions of a stretching temperature of 55°C and a stretching ratio of 5 times. The uniaxially stretched film was washed with water and dried to obtain a polarizer with a thickness of 12 μm.

(紫外線硬化性接著劑組成物之調製) 混合下述各成分後，進行脫泡，調製紫外線硬化性接著劑組成物。 3,4-環氧基環己基甲基-3,4-環氧基環己烷羧酸酯：45質量份 EPOLEAD GT-301(DAICEL公司製之脂環式環氧樹脂)：40質量份 1,4-丁二醇二縮水甘油醚：15質量份 三芳基

Figure 109108725-A0304-12-0020-10
六氟磷酸鹽：2.3質量份(固形分) 9,10-二丁氧基蒽：0.1質量份 1,4-二乙氧基萘：2.0質量份 又，三芳基
Figure 109108725-A0304-12-0020-10
六氟磷酸鹽係調配為50%碳酸伸丙酯溶液。(Preparation of ultraviolet curable adhesive composition) After mixing the following components, defoaming is performed to prepare an ultraviolet curable adhesive composition. 3,4-Epoxycyclohexylmethyl-3,4-epoxycyclohexane carboxylate: 45 parts by mass EPOLEAD GT-301 (alicyclic epoxy resin manufactured by DAICEL): 40 parts by mass 1 ,4-Butanediol diglycidyl ether: 15 parts by mass of triaryl
Figure 109108725-A0304-12-0020-10
Hexafluorophosphate: 2.3 parts by mass (solid content) 9,10-dibutoxyanthracene: 0.1 parts by mass 1,4-diethoxynaphthalene: 2.0 parts by mass, triaryl
Figure 109108725-A0304-12-0020-10
The hexafluorophosphate system is formulated as a 50% propylene carbonate solution.

(偏光板之製作) 於上述製作之保護膜101表面，以電暈輸出強度2.0kW、線速度18m/分鐘實施電暈放電處理。其次，於保護膜101之電暈放電處理面，以棒塗佈器以硬化後之膜厚成為約3μm之方式塗佈上述調製之紫外線硬化性接著劑組成物，形成紫外線硬化性接著劑層。 同樣，於上述製作之保護膜201表面實施電暈放電處理後，以硬化後之膜厚成為3μm之方式塗佈上述調製之紫外線硬化性接著劑組成物，形成紫外線硬化性接著劑層。(Making of polarizing plate) The surface of the protective film 101 produced above was subjected to corona discharge treatment at a corona output intensity of 2.0 kW and a linear velocity of 18 m/min. Next, on the corona discharge treatment surface of the protective film 101, the above-prepared ultraviolet curable adhesive composition is applied with a bar coater so that the cured film thickness becomes approximately 3 μm to form an ultraviolet curable adhesive layer. Similarly, after corona discharge treatment is performed on the surface of the protective film 201 prepared above, the prepared ultraviolet curable adhesive composition is applied so that the cured film thickness becomes 3 μm to form an ultraviolet curable adhesive layer.

其次，於上述製作之偏光器之一面，介隔紫外線硬化性接著劑層配置保護膜101，於另一面，介隔紫外線硬化性接著劑層配置保護膜201，獲得層合物。層合係使偏光器之吸收軸與保護膜之慢軸正交之方式進行。Next, on one side of the polarizer fabricated as described above, a protective film 101 is placed through the ultraviolet curable adhesive layer, and on the other side, a protective film 201 is placed through the ultraviolet curable adhesive layer to obtain a laminate. The lamination is performed in such a way that the absorption axis of the polarizer is orthogonal to the slow axis of the protective film.

其次，對所得層合物，使用附輸送帶之紫外線照射裝置(燈係FUSION UV SYSTEMS公司製之D燈泡)，以累積光量為750mJ/cm2 之方式照射紫外線，使紫外線硬化性接著劑層硬化。Secondly, to the obtained laminate, use an ultraviolet irradiation device with a conveyor belt (the lamp is a D bulb manufactured by FUSION UV SYSTEMS), and irradiate ultraviolet rays with a cumulative light amount of 750mJ/cm 2 to harden the ultraviolet curable adhesive layer. .

接著，於所得層合物之保護膜B上，貼合下述附黏著劑層之PET膜之黏著劑層(厚度20μm)。藉此獲得具有保護膜101(保護膜A)/接著劑層/偏光器/接著劑層/保護膜201(保護膜B)/黏著劑層/PET膜之層合構造的偏光板301。又，黏著劑層係將包含(甲基)丙烯酸系聚合物與交聯劑之丙烯酸系黏著劑組成物塗佈於PET膜上之後，經加熱乾燥(部分交聯)者。Next, on the protective film B of the obtained laminate, the following adhesive layer (thickness 20 μm) of the PET film with the adhesive layer was attached. Thereby, a polarizing plate 301 having a laminated structure of protective film 101 (protective film A)/adhesive layer/polarizer/adhesive layer/protective film 201 (protective film B)/adhesive layer/PET film is obtained. In addition, the adhesive layer is an acrylic adhesive composition comprising a (meth)acrylic polymer and a crosslinking agent, which is applied to a PET film and then dried (partially crosslinked) by heating.

＜偏光板302~323之製作＞ 除了將保護膜A及B變更如表5所示以外，與偏光板301同樣獲得偏光板302~323。＜Making of polarizing plate 302~323＞ Except that the protective films A and B were changed as shown in Table 5, polarizing plates 302 to 323 were obtained in the same manner as the polarizing plate 301.

＜評價＞ 藉以下方法測定所得偏光板之衝打性及(敲鍵試驗後之)顯示不均。＜Evaluation＞ The punchability and display unevenness (after the keystroke test) of the obtained polarizer were measured by the following method.

(衝打性) 圖3A及B係顯示實施例之偏光板100之衝打步驟之圖。圖3A係偏光板100之立體圖，圖3B係A-A線之部分剖面圖。(Rushing) 3A and B are diagrams showing the punching steps of the polarizing plate 100 of the embodiment. FIG. 3A is a perspective view of the polarizing plate 100, and FIG. 3B is a partial cross-sectional view along the line A-A.

如圖3A及B所示，所得偏光板100經由黏著劑層140貼合於PET膜170上。接著，貼合於PET膜170之偏光板100如圖3A所示，將1m見方之偏光板100(圖3A中的W為1m)衝打出9片10cm見方之正方形。相鄰之偏光板彼此之間隙p設為1cm。As shown in FIGS. 3A and B, the obtained polarizing plate 100 is attached to the PET film 170 via the adhesive layer 140. Next, the polarizing plate 100 attached to the PET film 170 is shown in FIG. 3A, and the polarizing plate 100 of 1 m square (W in FIG. 3A is 1 m) is punched out into 9 squares of 10 cm square. The gap p between adjacent polarizing plates is set to 1 cm.

衝打出之9片偏光板以光學顯微鏡觀察，計算所發生之龜裂個數及剝落並算出平均。接著，基於以下評價基準，評價衝打性。 ◎：龜裂、剝落均未觀察到。 〇：於2處以下發生龜裂或剝落。 〇△：於3~5處發生龜裂或剝落。 △：分別於3~5處發生龜裂及剝落。 ×：分別於6處以上發生龜裂及剝落。 〇△、〇及◎為實用上容許之程度。The 9 polarizing plates punched out were observed with an optical microscope, and the number of cracks and peeling occurred was counted and the average was calculated. Next, the punchability was evaluated based on the following evaluation criteria. ◎: Both cracks and peeling are not observed. ○: Cracking or peeling occurred in 2 or less places. ○△: Cracking or peeling occurred at 3 to 5 places. △: Cracks and peeling occurred at 3 to 5 places, respectively. ×: Cracks and peeling occurred at 6 or more places, respectively. ○△, ○ and ◎ are practically acceptable levels.

(顯示不均) (1)具有觸控面板構件之液晶顯示裝置之製作 自具有觸控面板構件之液晶顯示裝置的SONY公司製21.5吋VAIOTap21(SVT21219DJB)剝離預先貼合之2片偏光板，分別貼合上述製作之偏光板，獲得具有觸控面板構件之液晶顯示裝置。偏光板之貼合係剝除PET膜，將露出之黏著劑層密著於液晶胞而進行。(Uneven display) (1) Production of liquid crystal display device with touch panel components The 21.5-inch VAIOTap21 (SVT21219DJB) manufactured by SONY, which is a liquid crystal display device with touch panel components, was peeled off the two pre-bonded polarizing plates, and the above-mentioned polarizing plates were bonded respectively to obtain a liquid crystal display device with touch panel components. The bonding of the polarizing plate is performed by peeling off the PET film, and adhering the exposed adhesive layer to the liquid crystal cell.

(2)敲鍵試驗 所得液晶顯示裝置於經控制為40℃・95%RH之可變空調室內(朝日科學(股)製AES-200)中放置300小時。隨後，於同環境下使用敲鍵試驗機202型-950-2(觸控面板研究所股份有限公司)，以敲鍵速度為2Hz、荷重150g之條件，自蓋玻片側之上方以輸入筆按壓1萬5000次。又，輸入筆之筆尖材料係將鋪在橡膠下之測定盤設為玻璃基板，於其上以導電網成為玻璃側之方式設置，自上方以300g荷重按押輸入筆，以滑動距離5cm、往返1秒(以1秒往返5cm)之條件重複滑動。又，輸入筆之筆尖材料為聚縮醛，R為0.8mm。(2) Keystroke test The obtained liquid crystal display device was placed in a variable air-conditioning room (AES-200 manufactured by Asahi Scientific Co., Ltd.) controlled at 40°C and 95%RH for 300 hours. Then, in the same environment, use the keystroke testing machine 202-950-2 (Touch Panel Research Institute Co., Ltd.), press the input pen from the upper side of the cover glass under the condition that the keystroke speed is 2Hz and the load is 150g 15,000 times. In addition, the pen tip material of the input pen is made of a glass substrate with a measuring plate laid under the rubber, and a conductive mesh is set on it to become the glass side. The input pen is pressed from above with a load of 300g, and the sliding distance is 5cm. Repeat the sliding for 1 second (5cm back and forth in 1 second). In addition, the tip material of the input pen is polyacetal, and the R is 0.8mm.

(3)顯示不均 敲鍵試驗後之液晶顯示裝置於40℃・95%RH之環境下放置300小時。其次，於40℃・乾燥環境下放置2小時，隨後，於23℃・55%RH之環境下點亮24小時後，自顯示面板正面觀察顯示不均。顯示不均係基於以下基準評價。 ◎：未辨識到顯示面板之不均。 〇：顯示面板見到微小不均但品質上無影響。 〇△：顯示面板見到局部不均，但無法視認不均部分與無不均部分之邊界。 △：顯示面板見到局部不均，且可視認不均部分與無不均部分之邊界。 ×：顯示面板全面見到不均，且可明確視認不均部分與無不均部分。 〇△、〇及◎為實用上容許之程度。(3) Uneven display After the keystroke test, the LCD device is placed in an environment of 40℃ and 95%RH for 300 hours. Next, leave it at 40°C and a dry environment for 2 hours, and then light it up in an environment of 23°C and 55%RH for 24 hours, and observe the unevenness of the display from the front of the display panel. The display unevenness is evaluated based on the following criteria. ◎: The unevenness of the display panel is not recognized. ○: Minor unevenness is seen on the display panel but there is no effect on the quality. ○△: Partial unevenness is seen on the display panel, but the boundary between the uneven part and the non-uniform part cannot be seen. △: Partial unevenness is seen on the display panel, and the boundary between the uneven portion and the non-uniform portion can be visually recognized. ×: Unevenness is seen across the display panel, and unevenness and no unevenness can be clearly seen. ○△, ○ and ◎ are practically acceptable levels.

所得偏光板301~323之構成及評價結果示於表5。

Figure 02_image009
The composition and evaluation results of the obtained polarizing plates 301 to 323 are shown in Table 5.
Figure 02_image009

如表5所示可知，偏光板301~303、310~312及315~323(實施例)均係衝打性良好，顯示不均較少。As shown in Table 5, it can be seen that the polarizing plates 301 to 303, 310 to 312, and 315 to 323 (Examples) all have good punchability and less display unevenness.

尤其可知，藉由保護膜B之拉伸彈性模數高於保護膜A之拉伸彈性模數，而使衝打性更高，可更抑制顯示不均(偏光板320與322或317之對比)。此認為係因保護膜B具有適度硬度，而對於刀刃押入之變形較少，藉此產生之應力亦較少之故。In particular, it can be seen that the tensile elastic modulus of the protective film B is higher than the tensile elastic modulus of the protective film A, so that the punchability is higher and the display unevenness can be more suppressed (Comparison of polarizer 320 and 322 or 317 ). This is considered to be because the protective film B has a moderate hardness, and the deformation of the blade is less, and the stress generated thereby is also less.

又可知藉由使保護膜B之厚度比保護膜A之厚度更薄，而使衝打性更高，可更抑制顯示不均(偏光板301與323之對比)。此認為係因保護膜B適度薄，於抽出刀刃之際，不易卡住刀刃，而容易抑制龜裂；且藉由使保護膜B較薄，而使刀刃押入時之物理變形(應變)較少，產生之應力亦較小之故。It can also be seen that by making the thickness of the protective film B thinner than the thickness of the protective film A, the punchability is higher and the display unevenness can be more suppressed (comparison between polarizing plates 301 and 323). This is believed to be because the protective film B is moderately thin, it is not easy to jam the blade when the blade is drawn out, and it is easy to suppress cracks; and by making the protective film B thinner, the physical deformation (strain) of the blade is less when the blade is pushed in. , The stress produced is also small.

相對於此，可知偏光板305~309及313~314 (比較例)衝打性均差，亦產生顯示不均。且可知偏光板304(比較例)產生顯示不均。具體而言，偏光板305由於保護膜B中之橡膠粒子b之平均縱橫比較低，故認為無法充分緩和應力之故。偏光板304之顯示不均較差認為係由於保護膜B中之橡膠粒子b之平均縱橫比較高，橡膠粒子b之塑性變形與(甲基)丙烯酸系樹脂之塑性變形產生偏差，容易於橡膠粒子b與(甲基)丙烯酸系樹脂之間產生界面剝離，其結果，於保護膜B與接著劑層之間產生層間剝離之故。偏光板307認為係由於保護膜B不含橡膠粒子b，故過於脆，無法耐受衝打時之變形，而產生龜裂缺陷。On the other hand, it can be seen that the polarizing plates 305 to 309 and 313 to 314 (comparative examples) have poor punchability and display unevenness. In addition, it can be seen that the polarizing plate 304 (comparative example) has display unevenness. Specifically, since the polarizing plate 305 has a low average aspect ratio of the rubber particles b in the protective film B, it is considered that the stress cannot be sufficiently relieved. The poor display unevenness of the polarizer 304 is believed to be due to the high average aspect ratio of the rubber particles b in the protective film B, and the plastic deformation of the rubber particles b deviates from the plastic deformation of the (meth)acrylic resin, which is more likely to be compared with the rubber particles b. Interfacial peeling occurred with the (meth)acrylic resin, and as a result, interlayer peeling occurred between the protective film B and the adhesive layer. The polarizing plate 307 is considered to be because the protective film B does not contain the rubber particles b, so it is too brittle and cannot withstand the deformation during punching, resulting in cracking defects.

又，偏光板308認為由於保護膜A不含橡膠粒子a，故衝打時保護膜A容易產生龜裂。偏光板306中，衝打性或顯示不均較低認為係保護膜A中之橡膠粒子a的平均縱橫比過高，橡膠粒子a容易追隨保護膜A之變形，或對保護膜B施加之應力增加之故。偏光板313及314中，衝打性及顯示不均較低認為係保護膜B之PMI比率過多，膜的脆性變高，容易對橡膠粒子b施加過量負荷，也容易對樹脂施加負荷之故。In addition, the polarizing plate 308 considers that since the protective film A does not contain the rubber particles a, the protective film A is likely to be cracked during punching. In the polarizing plate 306, the impact or unevenness of display is low. It is considered that the average aspect ratio of the rubber particles a in the protective film A is too high, and the rubber particles a easily follow the deformation of the protective film A or the stress applied to the protective film B Because of the increase. Polarizers 313 and 314 have low punchability and low display unevenness. It is considered that the PMI ratio of the protective film B is too large, and the brittleness of the film becomes high, so that excessive load is easily applied to the rubber particles b, and a load is easily applied to the resin.

且，可知偏光板309之顯示不均比偏光板306進而更低。此認為係偏光板309所用之保護膜B中所含之(甲基)丙烯酸系樹脂不含源自苯基馬來醯亞胺之構造單位，故於橡膠粒子b與(甲基)丙烯酸系樹脂之間產生界面剝離之故。In addition, it can be seen that the display unevenness of the polarizing plate 309 is further lower than that of the polarizing plate 306. This is considered to be because the (meth)acrylic resin contained in the protective film B used in the polarizing plate 309 does not contain a structural unit derived from phenylmaleimide, so the rubber particles b and the (meth)acrylic resin Because of the interfacial peeling between them.

本申請案係基於2019年4月26日申請之PCT/JP2019/018115主張優先權。該申請案說明書及圖式中記載之內容全部援用於本說明書。 [產業上之可利用性]This application is based on the PCT/JP2019/018115 filed on April 26, 2019. The contents described in the application specification and drawings are all used in this specification. [Industrial availability]

依據本發明，可提供可抑制衝打時之龜裂或層間剝離，於高濕環境下長時間使用之際的敲鍵所致之顯示不均可減低之偏光板。According to the present invention, it is possible to provide a polarizing plate that can suppress cracks or delamination during punching, and can reduce display inconsistencies caused by key tapping during long-term use in a high-humidity environment.

100:偏光板 110:偏光器 120A:保護膜(保護膜A) 120B:保護膜(保護膜B) 130A,130B:接著劑層 140:黏著劑層 150a:橡膠粒子(橡膠粒子a) 150b:橡膠粒子(橡膠粒子b)100: Polarizing plate 110: Polarizer 120A: Protective film (protective film A) 120B: Protective film (protective film B) 130A, 130B: Adhesive layer 140: Adhesive layer 150a: Rubber particles (rubber particles a) 150b: Rubber particles (rubber particles b)

[圖1]係顯示本發明一實施形態之偏光板的剖面圖。 [圖2]係說明偏光板衝打步驟之推定機制的剖面圖。 [圖3A及B]係顯示實施例之偏光板衝打步驟之圖。[Fig. 1] is a cross-sectional view showing a polarizing plate according to an embodiment of the present invention. [Figure 2] is a cross-sectional view illustrating the estimation mechanism of the polarizing plate punching step. [FIGS. 3A and B] are diagrams showing the punching steps of the polarizing plate of the embodiment.

100:偏光板 100: Polarizing plate

110:偏光器 110: Polarizer

120A:保護膜(保護膜A) 120A: Protective film (protective film A)

120B:保護膜(保護膜B) 120B: Protective film (protective film B)

130A,130B:接著劑層 130A, 130B: Adhesive layer

140:黏著劑層 140: Adhesive layer

150a:橡膠粒子(橡膠粒子a) 150a: Rubber particles (rubber particles a)

150b:橡膠粒子(橡膠粒子b) 150b: Rubber particles (rubber particles b)

Claims (7)

一種偏光板，其係包含偏光器、配置於前述偏光器一面之保護膜A、配置於前述偏光器另一面之保護膜B與配置於前述保護膜B之與前述偏光器相反側之面之黏著劑層，前述保護膜A包含(甲基)丙烯酸系樹脂與橡膠粒子a，前述保護膜B包含(甲基)丙烯酸系樹脂與橡膠粒子b，前述保護膜A之沿厚度方向之剖面中，前述橡膠粒子a之平均縱橫比為1.0~1.1，前述保護膜B之沿厚度方向之剖面中，前述橡膠粒子b之平均縱橫比為1.2~3.0，前述保護膜B所含之前述(甲基)丙烯酸系樹脂係相對於構成前述(甲基)丙烯酸系樹脂之全部構造單位，包含50~95質量%之源自甲基丙烯酸甲酯之構造單位、1~25質量%之源自苯基馬來醯亞胺之構造單位與1~25質量%之源自丙烯酸烷酯之構造單位之共聚物。 A polarizing plate comprising a polarizer, a protective film A disposed on one side of the polarizer, a protective film B disposed on the other side of the polarizer, and an adhesive disposed on the surface of the protective film B opposite to the polarizer The agent layer, the protective film A includes (meth)acrylic resin and rubber particles a, the protective film B includes (meth)acrylic resin and rubber particles b, and in the cross section of the protective film A in the thickness direction, the The average aspect ratio of the rubber particles a is 1.0 to 1.1. In the cross section along the thickness direction of the protective film B, the average aspect ratio of the rubber particles b is 1.2 to 3.0. The (meth)acrylic acid contained in the protective film B Relative to all the structural units constituting the aforementioned (meth)acrylic resin, the resin system contains 50-95% by mass of structural units derived from methyl methacrylate and 1-25% by mass of phenyl maleic acid A copolymer of the structural unit of imine and the structural unit of 1-25% by mass derived from alkyl acrylate. 如請求項1之偏光板，其中前述保護膜B之25℃下之拉伸彈性模數高於前述保護膜A之25℃下之拉伸彈性模數。 The polarizing plate of claim 1, wherein the tensile elastic modulus of the protective film B at 25°C is higher than the tensile elastic modulus of the protective film A at 25°C. 如請求項2之偏光板，其中前述保護膜A之25℃下之拉伸彈性模數為1.6~2.6GPa，前述保護膜B之25℃下之拉伸彈性模數為2.4~3.4GPa。 Such as the polarizing plate of claim 2, wherein the tensile elastic modulus of the protective film A at 25°C is 1.6 to 2.6 GPa, and the tensile elastic modulus of the protective film B at 25° C. is 2.4 to 3.4 GPa. 如請求項2或3之偏光板，其中前述保護 膜B之前述橡膠粒子b之含量少於前述保護膜A之前述橡膠粒子a之含量。 Such as the polarizing plate of claim 2 or 3, wherein the aforementioned protection The content of the rubber particles b of the film B is less than the content of the rubber particles a of the protective film A. 如請求項1或2之偏光板，其中前述橡膠粒子a包含含有源自苯乙烯類之構造單位之丙烯酸系橡膠狀聚合物(a1)，前述橡膠粒子b包含含有源自苯乙烯類之構造單位之丙烯酸系橡膠狀聚合物(b1)，前述丙烯酸系橡膠狀聚合物(b1)之源自苯乙烯類之構造單位之含量多於前述丙烯酸系橡膠狀聚合物(a1)之源自苯乙烯類之構造單位之含量。 The polarizing plate of claim 1 or 2, wherein the rubber particles a include an acrylic rubber-like polymer (a1) containing structural units derived from styrene, and the rubber particles b include structural units derived from styrene The acrylic rubber-like polymer (b1), the aforementioned acrylic rubber-like polymer (b1) contains more styrene-derived structural units than the aforementioned acrylic rubber-like polymer (a1), which is derived from styrene The content of the structural unit. 如請求項1或2之偏光板，其中前述保護膜B之厚度薄於前述保護膜A之厚度。 The polarizing plate of claim 1 or 2, wherein the thickness of the protective film B is thinner than the thickness of the protective film A. 如請求項1或2之偏光板，其中前述保護膜A係聚甲基丙烯酸甲酯。The polarizing plate of claim 1 or 2, wherein the protective film A is polymethyl methacrylate.
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