TW201539065A - Method for fabricating polarizing plate - Google PatentsMethod for fabricating polarizing plate Download PDF
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- TW201539065A TW201539065A TW104106606A TW104106606A TW201539065A TW 201539065 A TW201539065 A TW 201539065A TW 104106606 A TW104106606 A TW 104106606A TW 104106606 A TW104106606 A TW 104106606A TW 201539065 A TW201539065 A TW 201539065A
- Prior art keywords
- polarizing plate
- protective film
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- 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
本發明係關於偏光板之製造方法。 The present invention relates to a method of manufacturing a polarizing plate.
偏光板被廣泛使用於液晶顯示裝置等的顯示裝置，特別近年被廣泛使用於薄型電視、各種移動式機器。作為偏光板，一般係於偏光片的單面或兩面使用接著劑貼合保護膜的構成者。 The polarizing plate is widely used in display devices such as liquid crystal display devices, and has been widely used in thin televisions and various mobile devices in recent years. As the polarizing plate, generally, a member in which a protective film is bonded to one surface or both surfaces of a polarizer using an adhesive is used.
偏光板除可以於包含單體膜(單獨膜)的偏光片(偏光膜)，隔著接著劑層貼合保護膜的方法(以下亦稱為「單體膜法」)製造外，亦可藉由包括：藉由塗佈而形成樹脂層於基材膜上的步驟；經由延伸、染色，該樹脂層成為偏光片層，得到偏光性積層膜的步驟；於偏光性積層膜的偏光片層上，隔著接著劑層貼合保護膜的步驟；保護膜貼合後，剝離除去基材膜的步驟；之方法(以下亦稱為「塗佈法」)製造。後者的方法，在步驟中膜的操作性佳的點、容易得到薄膜的偏光片層的點有利。 The polarizing plate can be produced by a method of bonding a protective film (hereinafter also referred to as a "single film method" to a polarizer (polarizing film) including a monomer film (separate film) via an adhesive layer. The method includes the steps of: forming a resin layer on a substrate film by coating; and forming, by extending and dyeing, the resin layer becomes a polarizer layer to obtain a polarizing laminated film; and on the polarizing layer of the polarizing laminated film The step of bonding the protective film via the adhesive layer; after the protective film is bonded, the step of peeling off the substrate film; and the method (hereinafter also referred to as "coating method"). The latter method is advantageous in that the operability of the film is good in the step, and the point of the polarizer layer of the film is easily obtained.
於特開2009-098653號公報(專利文獻1)及特開2009-093074號公報(專利文獻2)，記載藉由與塗佈法類似的方法製造偏光板。 In JP-A-2009-098653 (Patent Document 1) and JP-A-2009-093074 (Patent Document 2), it is described that a polarizing plate is produced by a method similar to the coating method.
專利文獻1：特開2009-098653號公報 Patent Document 1: JP-A-2009-098653
專利文獻2：特開2009-093074號公報 Patent Document 2: JP-A-2009-093074
伴隨薄型電視、移動式機器的普及，對偏光板的薄型化之要求近年日益提高。但是，若使偏光板薄化，有容易產生捲曲的問題。於偏光板產生不適當的捲曲時，藉由黏著劑層貼合偏光板於液晶胞等的顯示胞而成為顯示裝置時，容易咬入氣泡。如此的氣泡存在於如液晶顯示裝置的顯示裝置時，點亮時因氣泡而產生光散射，在黑色顯示狀態下產生漏光(氣泡變成亮點)的顯示上的缺陷。 With the spread of thin-type televisions and mobile devices, the demand for thinner polarizing plates has been increasing in recent years. However, if the polarizing plate is made thin, there is a problem that curling tends to occur. When the polarizing plate is improperly curled, when the polarizing plate is bonded to a display cell such as a liquid crystal cell by the adhesive layer to form a display device, air bubbles are easily caught. When such a bubble exists in a display device such as a liquid crystal display device, light is scattered by light bubbles during lighting, and a display defect occurs in a black display state (light bubbles become bright spots).
於專利文獻1及專利文獻2中記載若根據與前述塗佈法類似的方法，可抑制偏光板的捲曲。但是，該等文獻所謂的抑制捲曲的偏光板，係指不剝離除去前述塗佈法之基材膜而依原樣使用作為偏光片層的保護膜之偏光板，卻未提及關於剝離除去基材膜所得之包含偏光片層與保護膜的偏光板的捲曲。 Patent Document 1 and Patent Document 2 describe that curling of a polarizing plate can be suppressed according to a method similar to the above-described coating method. However, the polarizing plate for suppressing curling in the above-mentioned documents refers to a polarizing plate which does not peel off the base film of the coating method and uses a protective film as a polarizing plate layer as it is, but does not mention peeling off the substrate. The curl of the polarizing plate comprising the polarizer layer and the protective film obtained by the film.
本發明的目的，在於提供例如前述的塗佈法，於偏光性積層膜的偏光片層上，貼合保護膜後，剝離除去基材膜而製造偏光板的方法，且可抑制所得之偏光板的捲曲之製造方法。 An object of the present invention is to provide a method for producing a polarizing plate by peeling off a base film after bonding a protective film to a polarizing layer of a polarizing laminated film, for example, and to suppress the obtained polarizing plate. The manufacturing method of curling.
本發明提供以下所示的偏光板之製造方法。 The present invention provides a method of producing a polarizing plate shown below.
偏光板之製造方法，依序包括：於基材膜的至少一側的面上具備偏光片層的偏光性積層膜的偏光片層上，隔著接著劑層，貼合水分率調整為比25℃、55% RH的平衡水分率高之保護膜的步驟；以及剝離除去前述基材膜的步驟。  A method of producing a polarizing plate, comprising: adjusting a moisture content of a polarizing layer having a polarizing film layer on a surface of at least one side of a base film; A step of a protective film having a higher equilibrium moisture ratio than 25 ° C and 55% RH; and a step of peeling off the substrate film.
如記載的偏光板之製造方法，其中，於貼合前述保護膜的步驟中，前述保護膜的水分率為其飽和水分率的70%以下。  The method for producing a polarizing plate according to the above aspect, wherein, in the step of bonding the protective film, the moisture content of the protective film is 70% or less of the saturated moisture content.
如或記載的偏光板之製造方法，其中，前述偏光性積層膜係藉由包括如下步驟的方法製造：於前述基材膜的至少一側的面上，塗佈含有聚乙烯醇系樹脂的塗佈液後，使該塗佈液乾燥，藉此，形成聚乙烯醇系樹脂層，得到積層膜的步驟；延伸前述積層膜，得到延伸膜的步驟；以及將前述延伸膜的聚乙烯醇系樹脂層以二色性色素染色，形成前述偏光片層，藉此，得到偏光性積層膜的步驟。 The method for producing a polarizing plate according to the above aspect, wherein the polarizing laminated film is produced by a method comprising the steps of: coating on at least one side of the base film; After the coating liquid containing the polyvinyl alcohol-based resin is dried, the coating liquid is dried to form a polyvinyl alcohol-based resin layer to obtain a laminated film, and the step of stretching the laminated film to obtain a stretched film; The polyvinyl alcohol-based resin layer of the stretched film is dyed with a dichroic dye to form the polarizing plate layer, whereby a polarizing laminated film is obtained.
如~中任一項記載的偏光板之製造方法，其中，前述保護膜係包含纖維素酯系樹脂或(甲基)丙烯酸系樹脂。  The method for producing a polarizing plate according to any one of the above aspects, wherein the protective film comprises a cellulose ester resin or a (meth)acrylic resin.
如~中任一項記載的偏光板之製造方法，其中，前述偏光片層的厚度為10μm以下。  The method for producing a polarizing plate according to any one of  to  wherein the thickness of the polarizing plate layer is 10 μm or less.
根據本發明，於偏光性積層膜的偏光片層上，貼合保護膜後，剝離除去基材膜，製造包含偏光片層與貼合於其一側的面的保護膜的偏光板之方法，可抑制所得之偏光板的捲曲。 According to the present invention, a method of producing a polarizing plate comprising a polarizing film layer and a protective film attached to one surface of the polarizing film layer after the protective film is bonded to the polarizing layer of the polarizing laminate film is removed. The curl of the resulting polarizing plate can be suppressed.
1‧‧‧單面附有保護膜的偏光板 1‧‧‧ polarizing plate with protective film on one side
2‧‧‧兩面附有保護膜的偏光板 2‧‧‧ polarizing plates with protective film on both sides
5‧‧‧偏光片層 5‧‧‧Polarized film
6‧‧‧聚乙烯醇系樹脂層 6‧‧‧Polyvinyl alcohol resin layer
6’‧‧‧被延伸的聚乙烯醇系樹脂層 6'‧‧‧Extended polyvinyl alcohol resin layer
10‧‧‧第1保護膜 10‧‧‧1st protective film
15、25‧‧‧接著劑層 15, 25‧‧‧ adhesive layer
20‧‧‧第2保護膜 20‧‧‧2nd protective film
30‧‧‧基材膜 30‧‧‧Base film
30’‧‧‧被延伸的基材膜 30'‧‧‧Extended substrate film
100‧‧‧積層膜 100‧‧‧ laminated film
200‧‧‧延伸膜 200‧‧‧Extension film
300‧‧‧偏光性積層膜 300‧‧‧Polarized laminated film
400‧‧‧附有保護膜的偏光性積層膜 400‧‧‧Polarized laminated film with protective film
第1圖係表示關於本發明的偏光板之製造方法的較佳之一例的流程圖。 Fig. 1 is a flow chart showing a preferred example of the method for producing a polarizing plate of the present invention.
第2圖係表示偏光性積層膜的製造方法的較佳之一例的流程圖。 Fig. 2 is a flow chart showing a preferred example of a method for producing a polarizing laminated film.
第3圖係表示關於本發明的偏光板之製造方法的較佳之其他例的流程圖。 Fig. 3 is a flow chart showing another preferred example of the method for producing a polarizing plate of the present invention.
第4圖係表示樹脂層形成步驟所得之積層膜的層構成的一例之剖面示意圖。 Fig. 4 is a schematic cross-sectional view showing an example of a layer configuration of a laminated film obtained by the resin layer forming step.
第5圖係表示延伸步驟所得之延伸膜的層構成的一例之剖面示意圖。 Fig. 5 is a schematic cross-sectional view showing an example of a layer configuration of a stretched film obtained by the stretching step.
第6圖係表示染色步驟所得之偏光性積層膜的層構成的一例之剖面示意圖。 Fig. 6 is a schematic cross-sectional view showing an example of a layer configuration of a polarizing laminate film obtained by the dyeing step.
第7圖係表示第1保護膜貼合步驟所得之附有保護膜的偏光板的層構成的一例之剖面示意圖。 Fig. 7 is a schematic cross-sectional view showing an example of a layer configuration of a polarizing plate with a protective film obtained by the first protective film bonding step.
第8圖係表示剝離步驟所得之單面附有保護膜的偏光板的層構成之剖面示意圖。 Fig. 8 is a schematic cross-sectional view showing the layer constitution of a polarizing plate having a protective film on one side obtained by the peeling step.
第9圖係表示第2保護膜貼合步驟所得之兩面附有保 護膜的偏光板的層構成之剖面示意圖。 Figure 9 shows the two sides of the second protective film bonding step. A schematic cross-sectional view of the layer structure of the polarizing plate of the film.
第1圖係表示關於本發明的偏光板之製造方法的較佳之一例的流程圖。如第1圖所示的本發明之製造方法係包括下述步驟：(1)於基材膜的至少一側的面上具備偏光片層的偏光性積層膜的偏光片層上，隔著接著劑層，貼合水分率調整為比25℃、55% RH的平衡水分率高之第1保護膜的第1保護膜貼合步驟S10；(2)第1保護膜貼合步驟後，剝離除去前述基材膜的步驟S20。 Fig. 1 is a flow chart showing a preferred example of the method for producing a polarizing plate of the present invention. The manufacturing method of the present invention as shown in Fig. 1 includes the following steps: (1) a polarizing layer of a polarizing laminated film having a polarizing plate layer on at least one surface of a base film, followed by The first protective film bonding step S10 of the first protective film having a bonding water ratio higher than the equilibrium moisture ratio of 25° C. and 55% RH is adjusted, and (2) the first protective film bonding step is followed by peeling off. Step S20 of the aforementioned substrate film.
而且，如第2圖所示，偏光性積層膜係藉由如前述塗佈法製造，較佳為藉由包括如下步驟的方法製造：[a]於基材膜的至少一側的面上，塗佈含有聚乙烯醇系樹脂的塗佈液後，使其乾燥，藉此，形成聚乙烯醇系樹脂層，得到積層膜的樹脂層形成步驟S1-1；[b]延伸積層膜，得到延伸膜的延伸步驟S1-2；以及[c]將延伸膜的聚乙烯醇系樹脂層以二色性色素染色，形成前述偏光片層，藉此，得到前述偏光性積層膜的染色步驟S1-3。 Further, as shown in Fig. 2, the polarizing laminated film is produced by the above-described coating method, and is preferably produced by a method comprising the following steps: [a] on at least one side of the substrate film, After coating a coating liquid containing a polyvinyl alcohol-based resin and drying it, a polyvinyl alcohol-based resin layer is formed to obtain a resin layer forming step S1-1 of the laminated film; [b] the extended laminated film is extended Film extending step S1-2; and [c] dyeing the polyvinyl alcohol-based resin layer of the stretched film with a dichroic dye to form the polarizing layer, thereby obtaining a dyeing step S1-3 of the polarizing laminated film .
藉由以上的製造方法，得到第1保護膜貼合於偏光片層的一側的面之單面附有保護膜的偏光板。如第3圖所示，剝離步驟S20後，設置單面附有保護膜的偏光板的偏光片層側的面上隔著接著劑層貼合第2保護膜的第 2保護膜貼合步驟S30，亦可得到兩面附有保護膜的偏光板。 According to the above production method, a polarizing plate having a protective film on one surface of the surface on which the first protective film is bonded to the polarizing plate layer is obtained. As shown in FIG. 3, after the peeling step S20, the surface of the polarizing plate layer on the side of the polarizing plate having the protective film provided on one side thereof is bonded to the surface of the second protective film via the adhesive layer. 2 The protective film bonding step S30 can also obtain a polarizing plate with a protective film on both sides.
再者，所謂本發明的偏光板(藉由本發明的偏光板之製造方法所得之偏光板)，係指包含偏光片層以及隔著接著劑層積層於其至少一側的面的保護膜者(亦即單面附有保護膜的偏光板或兩面附有保護膜的偏光板)，不具備包含於其前驅物之偏光性積層膜的基材膜者。但是，藉由本發明之製造方法所得之偏光板，可於其上積層如其他膜、層的其他光學構件(周邊構件)而設為複合偏光板，或可使用作為複合偏光板。偏光片層可為使二色性色素吸附配向於被一軸延伸的聚乙烯醇系樹脂層(或薄膜)者。 In addition, the polarizing plate of the present invention (the polarizing plate obtained by the method for producing a polarizing plate of the present invention) refers to a protective film including a polarizing plate layer and a surface on which at least one layer is laminated via an adhesive layer ( That is, a polarizing plate having a protective film on one side or a polarizing plate having a protective film on both sides thereof, and a base film having no polarizing laminated film contained in the precursor thereof. However, the polarizing plate obtained by the production method of the present invention may be formed as a composite polarizing plate by laminating other optical members (peripheral members) such as other films and layers thereon, or may be used as a composite polarizing plate. The polarizer layer may be one in which a dichroic dye is adsorbed to a polyvinyl alcohol-based resin layer (or film) which is extended by one axis.
而且，所謂本發明的偏光性積層膜，係指具備基材膜、與積層於其至少一側的面上之偏光片層者，且沒有貼合保護膜者。以第1保護膜貼合步驟S10，於偏光片層貼合第1保護膜所成的偏光性積層膜，以下為了與偏光性積層膜區分，亦稱為「附有保護膜的偏光性積層膜」。 In addition, the polarizing laminate film of the present invention refers to a polarizer layer having a base film and a layer laminated on at least one side thereof, and is not bonded to a protective film. In the first protective film bonding step S10, the polarizing laminated film formed by bonding the first protective film to the polarizing plate layer is hereinafter referred to as "a polarizing laminated film with a protective film" for distinguishing it from the polarizing laminated film. "."
以下，詳細說明各步驟。再者，於樹脂層形成步驟S1-1中，聚乙烯醇系樹脂層可形成於基材膜的兩面，以下主要說明形成於單面的情形。 Hereinafter, each step will be described in detail. In the resin layer forming step S1-1, the polyvinyl alcohol-based resin layer can be formed on both surfaces of the base film, and the case where it is formed on one surface will be mainly described below.
〈第1保護膜貼合步驟S10〉 <First protective film bonding step S10>
如前述之偏光性積層膜，較佳為藉由[a]樹脂形成步驟S1-1、[b]延伸步驟S1-2及[c]染色步驟S1-3的方法製造。 The polarizing laminate film as described above is preferably produced by the method of [a] resin forming step S1-1, [b] extending step S1-2, and [c] dyeing step S1-3.
[a]樹脂形成步驟S1-1 [a] Resin formation step S1-1
參照第4圖，本步驟係於基材膜30的至少一側的面，形成聚乙烯醇系樹脂層6，得到偏光性積層膜100的步驟。該聚乙烯醇系樹脂層6係經由延伸步驟S1-2及染色步驟S1-3而成為偏光片層5的層。聚乙烯醇系樹脂層6係可藉由於基材膜30的單面或兩面塗佈含有聚乙烯醇系樹脂的塗佈液，使塗佈層乾燥而形成。 Referring to Fig. 4, this step is a step of forming a polyvinyl alcohol-based resin layer 6 on at least one surface of the base film 30 to obtain a polarizing laminated film 100. This polyvinyl alcohol-based resin layer 6 becomes a layer of the polarizer layer 5 via the extending step S1-2 and the dyeing step S1-3. The polyvinyl alcohol-based resin layer 6 can be formed by applying a coating liquid containing a polyvinyl alcohol-based resin on one surface or both surfaces of the base film 30 to dry the coating layer.
基材膜30可由熱塑性樹脂構成，其中較佳為由透明性、機械強度、熱安定性、延伸性等優異的熱塑性樹脂構成。如此的熱塑性樹脂的具體例，例如包括如鏈狀聚烯烴系樹脂、環狀聚烯烴系樹脂(降莰烯系樹脂等)的聚烯烴系樹脂；聚酯系樹脂；(甲基)丙烯酸系樹脂；如纖維素三乙酸酯、纖維素二乙酸酯的纖維素系樹脂；聚碳酸酯系樹脂；聚乙烯醇系樹脂；聚乙酸乙烯酯系樹脂；聚芳酸酯系樹脂；聚苯乙烯系樹脂；聚醚碸系樹脂；聚碸系樹脂；聚醯胺系樹脂；聚醯亞胺系樹脂；以及該等的混合物、共聚物。 The base film 30 may be composed of a thermoplastic resin, and is preferably made of a thermoplastic resin excellent in transparency, mechanical strength, thermal stability, and elongation. Specific examples of the thermoplastic resin include, for example, a polyolefin resin such as a chain polyolefin resin or a cyclic polyolefin resin (such as a decene-based resin); a polyester resin; and a (meth)acrylic resin. a cellulose resin such as cellulose triacetate or cellulose diacetate; a polycarbonate resin; a polyvinyl alcohol resin; a polyvinyl acetate resin; a polyarylate resin; Resin; polyether oxime resin; polyfluorene resin; polyamine resin; polyimine resin; and mixtures and copolymers thereof.
再者，於本說明書中，所謂「(甲基)丙烯酸」係意指選自丙烯酸及甲基丙烯酸的至少一者。所謂「(甲基)丙烯醯基」等之時，也相同。 In the present specification, the term "(meth)acrylic acid" means at least one selected from the group consisting of acrylic acid and methacrylic acid. The same applies to "(meth)acrylonitrile" or the like.
基材膜30係可為包含含有1種或2種以上的熱塑性樹脂的一個樹脂層的單層構造，亦可為包含1種或2種以上的熱塑性樹脂的樹脂層複數積層而成的多層構造。基材膜30係於後述的延伸步驟S1-2延伸積層膜100時，在以可適宜延伸聚乙烯醇系樹脂層6的延伸溫度延伸 之樹脂來構成較佳。 The base film 30 may have a single layer structure including one resin layer containing one or two or more kinds of thermoplastic resins, or a multilayer structure in which a plurality of resin layers including one or two or more kinds of thermoplastic resins are laminated. . When the base film 30 is extended in the extending step S1-2 to be described later, the laminated film 100 is extended at an extension temperature at which the polyvinyl alcohol-based resin layer 6 can be suitably extended. The resin is preferably constructed.
基材膜30係可含有添加劑。作為添加劑，例如紫外線吸收劑、抗氧化劑、潤滑劑、可塑劑、離型劑、著色防止劑、難燃劑、成核劑、抗靜電劑、顏料及著色劑等。基材膜30中熱塑性樹脂的含量，較佳為50~100重量%，更佳為50~99重量%，更加佳為60~98重量%，特別佳為70~97重量%。 The base film 30 may contain an additive. As the additive, for example, an ultraviolet absorber, an antioxidant, a lubricant, a plasticizer, a release agent, a coloring inhibitor, a flame retardant, a nucleating agent, an antistatic agent, a pigment, a coloring agent, and the like. The content of the thermoplastic resin in the base film 30 is preferably from 50 to 100% by weight, more preferably from 50 to 99% by weight, still more preferably from 60 to 98% by weight, particularly preferably from 70 to 97% by weight.
基材膜30的厚度，通常從強度、操作性等的作業性的點，為1~500μm，較佳為1~300μm，更佳為5~200μm，更加佳為5~150μm。 The thickness of the base film 30 is usually from 1 to 500 μm, preferably from 1 to 300 μm, more preferably from 5 to 200 μm, still more preferably from 5 to 150 μm, from the viewpoint of workability such as strength and workability.
塗佈於基材膜30的塗佈液，較佳為使聚乙烯醇系樹脂的粉末溶解於良溶劑(例如水)所得之聚乙烯醇系樹脂溶液。作為聚乙烯醇系樹脂，例如聚乙烯醇系樹脂及其衍生物。作為聚乙烯醇系樹脂的衍生物，除聚乙烯縮甲醛、聚乙烯縮乙醛等外，可舉例如聚乙烯醇系樹脂以如乙烯、丙烯的烯烴類改性者；以如丙烯酸、甲基丙烯酸、丁烯酸的不飽和羧酸類改性者；以不飽和羧酸的烷酯改性者；以(甲基)丙烯醯胺改性者等。改性的比例以未達30莫耳%為較佳，未達10莫耳%為更佳。進行超過30莫耳%的改性時，難以吸附二色性色素，產生偏光性能變低的缺陷。上述聚乙烯醇系樹脂中，以使用聚乙烯醇樹脂較佳。 The coating liquid applied to the base film 30 is preferably a polyvinyl alcohol-based resin solution obtained by dissolving a powder of a polyvinyl alcohol-based resin in a good solvent (for example, water). Examples of the polyvinyl alcohol-based resin include polyvinyl alcohol-based resins and derivatives thereof. Examples of the derivative of the polyvinyl alcohol-based resin include, in addition to polyvinyl formal, polyvinyl acetal, and the like, a polyvinyl alcohol-based resin modified with an olefin such as ethylene or propylene; and, for example, acrylic acid or methyl group. Modified by unsaturated carboxylic acid of acrylic acid or crotonic acid; modified by alkyl ester of unsaturated carboxylic acid; modified by (meth) acrylamide. The proportion of the modification is preferably less than 30 mol%, and more preferably less than 10 mol%. When the modification is more than 30 mol%, it is difficult to adsorb the dichroic dye, and the polarizing performance is lowered. Among the above polyvinyl alcohol-based resins, a polyvinyl alcohol resin is preferably used.
聚乙烯醇系樹脂的平均聚合度為100~10000的範圍較佳，1000~10000的範圍更佳，1500~8000的範圍更加佳，2000~5000的範圍最佳。平均聚合度係可根據JIS K6726-1994「聚乙烯醇測試方法」規定的方法求得。平均聚合度未達100時，難以得到較佳的偏光性能，超過10000時，對溶劑的溶解性惡化，聚乙烯醇系樹脂層的形成變困難。 The polyvinyl alcohol-based resin preferably has an average polymerization degree of from 100 to 10,000, more preferably from 1,000 to 10,000, more preferably from 1,500 to 8,000, and most preferably from 2000 to 5,000. The average degree of polymerization can be based on JIS The method specified in K6726-1994 "Test Method for Polyvinyl Alcohol" is obtained. When the average degree of polymerization is less than 100, it is difficult to obtain a preferable polarizing performance, and when it exceeds 10,000, the solubility in a solvent is deteriorated, and formation of a polyvinyl alcohol-based resin layer becomes difficult.
聚乙烯醇系樹脂較佳為聚乙酸乙烯酯系樹脂的皂化物。皂化度的範圍為80莫耳%以上，又90莫耳%以上，特別是94莫耳%以上為較佳。皂化度太低時，成為偏光性積層膜、偏光板時的耐久性、耐濕熱性可能變得不足。而且，雖可為完全皂化物(皂化度為100莫耳%者)，但若皂化度太高，染色速度變慢，為了賦予充分的偏光性能，製造時間變長，視情況，有時無法得到具有充分的偏光性能的偏光片層。所以，其皂化度為99.5莫耳%以下，又以99.0莫耳%以下較佳。 The polyvinyl alcohol-based resin is preferably a saponified product of a polyvinyl acetate-based resin. The degree of saponification is in the range of 80 mol% or more, and more preferably 90 mol% or more, particularly preferably 94 mol% or more. When the degree of saponification is too low, durability and heat and humidity resistance in the case of a polarizing laminated film or a polarizing plate may become insufficient. Further, although it may be a completely saponified product (the degree of saponification is 100 mol%), if the degree of saponification is too high, the dyeing speed is slow, and in order to impart sufficient polarizing performance, the production time becomes long, and depending on the case, sometimes it may not be obtained. A polarizer layer having sufficient polarizing properties. Therefore, the degree of saponification is 99.5 mol% or less, and preferably 99.0 mol% or less.
所謂皂化度係指包含於聚乙烯醇系樹脂的原料之聚乙酸乙烯酯系樹脂的乙酸基(乙醯氧基：-OCOCH3)藉由皂化處理變化成羥基的比例，以單位比(莫耳比)表示者，以下述式定義：皂化度(莫耳%)=[(羥基的數目)÷(羥基的數目+乙酸基的數目)]。皂化度，可根據JIS K 6726(1994)求得。表示皂化度越高，羥基的比例愈高，因此表示阻礙結晶化的乙酸基的比例低。 The degree of saponification refers to the ratio of the acetic acid group (acetoxy group: -OCOCH 3 ) of the polyvinyl acetate-based resin contained in the raw material of the polyvinyl alcohol-based resin to the hydroxyl group by saponification treatment, in units of ratio (mole The ratio is expressed by the following formula: degree of saponification (% by mole) = [(number of hydroxyl groups) ÷ (number of hydroxyl groups + number of acetate groups)]. The degree of saponification can be determined in accordance with JIS K 6726 (1994). The higher the degree of saponification, the higher the proportion of the hydroxyl group, and therefore the lower the proportion of the acetate group which hinders crystallization.
作為聚乙酸乙烯酯系樹脂，除乙酸乙烯酯的均聚物之聚乙酸乙烯酯外，例示可與乙酸乙烯酯共聚合的其他單體之共聚物等。作為可與乙酸乙烯酯共聚合的其 他單體，例如不飽和羧酸類、烯烴類、乙烯醚類、不飽和磺酸類、具有銨基的(甲基)丙烯醯胺類等。 As the polyvinyl acetate-based resin, in addition to the polyvinyl acetate of the homopolymer of vinyl acetate, a copolymer of another monomer copolymerizable with vinyl acetate or the like is exemplified. As a copolymerizable with vinyl acetate The monomers are, for example, unsaturated carboxylic acids, olefins, vinyl ethers, unsaturated sulfonic acids, (meth) acrylamides having an ammonium group, and the like.
塗佈液係依據需要而可含有可塑劑、界面活性劑等的添加劑。作為可塑劑，可使用聚醇或其縮合物等，例如丙三醇、二丙三醇、三丙三醇、乙二醇、丙二醇、聚乙二醇等。添加劑的調配量，適合為聚乙烯醇系樹脂的20重量%以下。 The coating liquid may contain an additive such as a plasticizer or a surfactant as needed. As the plasticizer, a polyol or a condensate thereof, or the like, for example, glycerin, diglycerin, triglycerin, ethylene glycol, propylene glycol, polyethylene glycol or the like can be used. The amount of the additive to be added is preferably 20% by weight or less based on the polyvinyl alcohol-based resin.
塗佈上述塗佈液於基材膜30的方法，可從線棒塗佈法；如反轉塗佈法、凹版塗佈法的滾輪塗佈法；狹縫塗佈法；缺角輪塗佈法；唇式塗佈法；旋轉塗佈法；網版塗佈法；噴泉塗佈法；浸塗法；噴塗法；等的方法適當地選擇。 The method of applying the above coating liquid to the base film 30 can be carried out by a wire bar coating method; for example, a roll coating method by a reverse coating method or a gravure coating method; a slit coating method; a corner wheel coating method Method; lip coating method; spin coating method; screen coating method; fountain coating method; dip coating method; spraying method;
塗佈層(乾燥前的聚乙烯醇系樹脂層)的乾燥溫度及乾燥時間，依據包含於塗佈液的溶劑之種類而設定。乾燥溫度例如為50~200℃，較佳為60~150℃。溶劑包含水時，乾燥溫度以80℃較佳。 The drying temperature and drying time of the coating layer (polyvinyl alcohol-based resin layer before drying) are set depending on the kind of the solvent contained in the coating liquid. The drying temperature is, for example, 50 to 200 ° C, preferably 60 to 150 ° C. When the solvent contains water, the drying temperature is preferably 80 °C.
聚乙烯醇系樹脂層6可只形成於基材膜30的一側的面，亦可形成於兩面。形成於兩面時，因可從1片偏光性積層膜300，得到2片偏光板，故在偏光板的生產效率的面上有利。 The polyvinyl alcohol-based resin layer 6 may be formed only on one side of the base film 30 or on both sides. When it is formed on both surfaces, since two polarizing plates can be obtained from one polarizing laminated film 300, it is advantageous in the production efficiency of the polarizing plate.
積層膜100的聚乙烯醇系樹脂層6的厚度，較佳為3~30μm，更佳為5~20μm。若為只具有該範圍內的厚度之聚乙烯醇系樹脂層6，經過後述的延伸步驟S1-2及染色步驟S1-3，二色性色素的染色性良好，偏光性能優， 且可得到充分薄(例如厚度10μm以下)的偏光片層5。聚乙烯醇系樹脂層6的厚度未達3μm時，延伸後變得太薄，染色性有惡化的傾向。 The thickness of the polyvinyl alcohol-based resin layer 6 of the laminated film 100 is preferably 3 to 30 μm, more preferably 5 to 20 μm. When the polyvinyl alcohol-based resin layer 6 having only the thickness in the range is subjected to the extending step S1-2 and the dyeing step S1-3 described later, the dyeability of the dichroic dye is good, and the polarizing performance is excellent. Further, a polarizing plate layer 5 sufficiently thin (for example, having a thickness of 10 μm or less) can be obtained. When the thickness of the polyvinyl alcohol-based resin layer 6 is less than 3 μm, it tends to be too thin after stretching, and the dyeability tends to be deteriorated.
於塗佈液的塗佈之前，為了提高基材膜30與聚乙烯醇系樹脂層6的密合性，於至少聚乙烯醇系樹脂層6所形成的側之基材膜30的表面，亦可實施電暈處理、電漿處理、火焰(flame)處理等。 Before the application of the coating liquid, in order to improve the adhesion between the base film 30 and the polyvinyl alcohol-based resin layer 6, the surface of the base film 30 on the side where at least the polyvinyl alcohol-based resin layer 6 is formed is also Corona treatment, plasma treatment, flame treatment, and the like can be performed.
而且，於塗佈液的塗佈之前，為了提高基材膜30與聚乙烯醇系樹脂層6的密合性，於基材膜30上，可隔著底塗(primer)層等而形成聚乙烯醇系樹脂層6。 Further, before the application of the coating liquid, in order to improve the adhesion between the base film 30 and the polyvinyl alcohol-based resin layer 6, a base layer 30 may be formed on the base film 30 via a primer layer or the like. A vinyl alcohol-based resin layer 6.
底塗層係可藉由將底塗層形成用塗佈液塗佈於基材膜30的表面後，使其乾燥而形成。底塗層形成用塗佈液係包含可發揮基材膜30與聚乙烯醇系樹脂層6之兩者某種強度之密合力之成分。底塗層形成用塗佈液通常含有賦予如此的密合力之樹脂成分及溶劑。作為樹脂成分，較佳為使用透明性、熱安定性、延伸性等優之熱塑性樹脂，例如(甲基)丙烯酸系樹脂，聚乙烯醇系樹脂等。其中，使用賦予良好的密合力之聚乙烯醇系樹脂較佳。更佳為聚乙烯醇樹脂。作為溶劑，通常使用可溶解上述樹脂成分的一般有機溶劑、水系溶劑，但從以水作為溶劑的塗佈液形成底塗層為較佳。 The undercoat layer can be formed by applying a coating liquid for forming an undercoat layer onto the surface of the base film 30 and then drying it. The coating liquid for forming an undercoat layer contains a component which can exhibit a certain strength of adhesion between the base film 30 and the polyvinyl alcohol-based resin layer 6. The coating liquid for forming an undercoat layer usually contains a resin component and a solvent which impart such an adhesive force. As the resin component, a thermoplastic resin excellent in transparency, heat stability, and elongation, for example, a (meth)acrylic resin, a polyvinyl alcohol-based resin, or the like is preferably used. Among them, a polyvinyl alcohol-based resin which imparts a good adhesion is preferable. More preferably, it is a polyvinyl alcohol resin. As the solvent, a general organic solvent or an aqueous solvent which can dissolve the above resin component is usually used, but an undercoat layer is preferably formed from a coating liquid containing water as a solvent.
為了提高底塗層的強度，亦可添加交聯劑於底塗層形成用塗佈液。交聯劑依據所使用的熱塑性樹脂的種類，可從有機系、無機系等習知者中選擇適合者。列 舉交聯劑之例時，為例如環氧系、異氰酸酯系、二醛系、金屬系(金屬鹽、金屬氧化物、金屬氫氧化物、有機金屬化合物)、高分子系的交聯劑。於使用聚乙烯醇系樹脂作為形成底塗層的樹脂成分時，適合使用聚醯胺環氧樹脂、羥甲基化三聚氰胺樹脂、二醛系交聯劑、金屬螯合物系交聯劑等。 In order to increase the strength of the undercoat layer, a crosslinking agent may be added to the coating liquid for forming an undercoat layer. The crosslinking agent can be selected from conventional ones such as an organic system and an inorganic system depending on the type of the thermoplastic resin to be used. Column Examples of the crosslinking agent include an epoxy-based, isocyanate-based, dialdehyde-based, metal-based (metal salt, metal oxide, metal hydroxide, or organometallic compound) and a polymer-based crosslinking agent. When a polyvinyl alcohol-based resin is used as the resin component for forming the undercoat layer, a polyamide solvent, a methylolated melamine resin, a dialdehyde-based crosslinking agent, a metal chelate-based crosslinking agent, or the like is preferably used.
底塗層的厚度以0.05~1μm左右較佳。更佳為0.1~0.4μm。若比0.05μm還薄，基材膜30與聚乙烯醇系樹脂層6的密合力之提高效果小，若比1μm還厚，不利於偏光板的薄膜化。 The thickness of the undercoat layer is preferably about 0.05 to 1 μm. More preferably, it is 0.1 to 0.4 μm. When it is thinner than 0.05 μm, the effect of improving the adhesion between the base film 30 and the polyvinyl alcohol-based resin layer 6 is small, and if it is thicker than 1 μm, it is disadvantageous for thinning of the polarizing plate.
塗佈底塗層形成用塗佈液於基材膜30的方法，可與聚乙烯醇系樹脂層形成用的塗佈液相同。底塗層係塗佈於塗有聚乙烯醇系樹脂層形成用的塗佈液的面。包含底塗層形成用塗佈液的塗佈層的乾燥溫度，例如為50~200℃，較佳為60~150℃。於溶劑包含水時，乾燥溫度以80℃以上較佳。 The method of applying the coating liquid for forming an undercoat layer to the base film 30 can be the same as the coating liquid for forming a polyvinyl alcohol-based resin layer. The undercoat layer is applied to a surface coated with a coating liquid for forming a polyvinyl alcohol-based resin layer. The drying temperature of the coating layer containing the coating liquid for forming an undercoat layer is, for example, 50 to 200 ° C, preferably 60 to 150 ° C. When the solvent contains water, the drying temperature is preferably 80 ° C or higher.
[b]延伸步驟S1-2 [b]Extension step S1-2
參考第5圖，本步驟係將包含基材膜30與聚乙烯醇系樹脂層6的積層膜100進行延伸，得到所延伸的包含基材膜30’與聚乙烯醇系樹脂層6’的延伸膜200之步驟。延伸處理通常為一軸延伸。 Referring to Fig. 5, in this step, the laminated film 100 including the base film 30 and the polyvinyl alcohol-based resin layer 6 is stretched to obtain an extended extension of the base film 30' and the polyvinyl alcohol-based resin layer 6'. The step of film 200. The extension process is typically a one-axis extension.
積層膜100的延伸倍率，可依據所期望的偏光特性而適當地選擇，較佳為相對於積層膜100的原本長度超過5倍且17倍以下，更佳為超過5倍且8倍以下。延 伸倍率為5倍以下時，因聚乙烯醇系樹脂層6’無法充分配向，故有時偏光片層5的偏光度無法充分變高。另一方面，延伸倍率超過17倍時，容易產生延伸時膜的斷裂，同時延伸膜200的厚度變得比需要地薄，在後續步驟的加工性及操作性恐會降低。 The stretching ratio of the laminated film 100 can be appropriately selected depending on the desired polarizing characteristics, and is preferably more than 5 times and 17 times or less, more preferably more than 5 times and 8 times or less with respect to the original length of the laminated film 100. Delay When the draw ratio is 5 or less, the polyvinyl alcohol-based resin layer 6' cannot be sufficiently aligned, and thus the degree of polarization of the polarizer layer 5 may not be sufficiently high. On the other hand, when the stretching ratio exceeds 17 times, the film is likely to be broken at the time of stretching, and the thickness of the stretching film 200 becomes thinner than necessary, and the workability and workability in the subsequent step may be lowered.
延伸處理不限於一階段的延伸，可以多階段進行。此時，可使多階段的延伸處理全部在染色步驟S1-3前連續地進行，亦可使第2階段以後的延伸處理與染色步驟S1-3之染色處理及/或交聯處理同時進行。如此地於進行多階段延伸處理時，以延伸處理的全部階段合併在一起成為超過5倍的延伸倍率之方式進行延伸處理較佳。 The extension processing is not limited to one-stage extension and can be performed in multiple stages. In this case, the multi-stage stretching treatment may be continuously performed before the dyeing step S1-3, or the stretching treatment after the second stage or the dyeing treatment and/or the crosslinking treatment of the dyeing step S1-3 may be simultaneously performed. When performing the multi-stage stretching process as described above, it is preferable to carry out the stretching treatment so that all the stages of the stretching process are combined to have a stretching ratio of more than 5 times.
延伸處理係除可為對膜的長度方向(膜的傳送方向)進行延伸之縱向延伸，亦可為對膜的寬度方向延伸之橫向延伸或斜向延伸等。作為縱向延伸方式，例如使用滾輪延伸的滾輪間延伸、壓縮延伸、使用夾頭(chuck或夾具(clip))延伸等，作為橫向延伸方式，例如拉幅(Tenter)法等。延伸處理可採用潤濕式延伸方法、乾式延伸方法之任一種，但使用乾式延伸方法者，在延伸溫度可從廣的範圍選擇之點為較佳。 The stretching treatment may be a longitudinal extension extending in the longitudinal direction of the film (the conveying direction of the film), or a lateral extension or oblique extension extending in the width direction of the film. As the longitudinal stretching method, for example, a roller extending extension between the rollers, a compression extension, a chuck (clip or clip) extension, or the like is used as a lateral stretching method, for example, a tenter method. The stretching treatment may be either a wet stretching method or a dry stretching method, but in the case of using a dry stretching method, it is preferred that the stretching temperature is selected from a wide range.
延伸溫度係設定為聚乙烯醇系樹脂層6與基材膜30全部顯示可能延伸程度的流動性之溫度以上，較佳為基材膜30的相轉移溫度(熔點或玻璃轉化溫度)的-30℃至+30℃的範圍，更佳為-30℃至+5℃的範圍，更加佳為-25℃至+0℃的範圍。基材膜30為包含複數樹脂層時，上 述相轉移溫度係指該複數樹脂層所示的相轉移溫度中最高的相轉移溫度。 The elongation temperature is set to a temperature at which the polyvinyl alcohol-based resin layer 6 and the base film 30 all exhibit fluidity of a possible degree of elongation, and preferably -30 of the phase transition temperature (melting point or glass transition temperature) of the substrate film 30. The range of °C to +30 ° C, more preferably in the range of -30 ° C to +5 ° C, more preferably in the range of -25 ° C to +0 ° C. When the base film 30 is composed of a plurality of resin layers, The phase transition temperature refers to the highest phase transition temperature among the phase transition temperatures indicated by the plurality of resin layers.
延伸溫度低於相轉移溫度的-30℃時，難以達成超過5倍的高倍率延伸，或基材膜30的流動性太低，延伸處理有變困難的傾向。延伸溫度超過相轉移溫度的+30℃時，基材膜30的流動性太高，延伸有變困難的傾向。由於更容易達成超過5倍的高倍率延伸，延伸溫度為上述範圍內，更佳為120℃以上。 When the stretching temperature is lower than -30 ° C of the phase transition temperature, it is difficult to achieve a high-magnification extension of more than 5 times, or the fluidity of the base film 30 is too low, and the elongation treatment tends to be difficult. When the stretching temperature exceeds +30 ° C of the phase transition temperature, the fluidity of the base film 30 is too high, and the elongation tends to be difficult. Since it is easier to achieve a high-magnification extension of more than 5 times, the stretching temperature is in the above range, more preferably 120 °C or more.
延伸處理之積層膜100的加熱方法，有區域加熱法(例如吹入熱風調整至預定溫度的加熱爐之延伸區域內進行加熱的方法)；使用滾輪延伸時，加熱滾輪本體的方法；加熱器加熱法(將紅外線加熱器、鹵素燈加熱器、平板式加熱器等設置於積層膜100上下以輻射熱加熱的方法)等。於滾輪間延伸方式中，從延伸溫度的均勻性之觀點，較佳為區域加熱法。 The heating method of the laminated film 100 for stretching treatment includes a zone heating method (for example, a method of heating in an extended region of a heating furnace in which hot air is adjusted to a predetermined temperature); a method of heating the roller body when the roller is extended; heater heating A method (a method in which an infrared heater, a halogen lamp heater, a plate heater, or the like is provided above and below the laminated film 100 to heat the radiant heat) or the like. In the method of extending between the rolls, from the viewpoint of the uniformity of the stretching temperature, the area heating method is preferred.
於延伸步驟S1-2前，可設置預熱積層膜100的預熱處理步驟。作為預熱方法，可使用與延伸處理之加熱方法相同的方法。預熱溫度為延伸溫度的-50℃至±0℃的範圍較佳，延伸溫度的-40℃至-10℃的範圍更佳。 The preheating step of the preheating laminated film 100 may be provided before the extending step S1-2. As the preheating method, the same method as the heating method of the elongation treatment can be used. The preheating temperature is preferably in the range of -50 ° C to ± 0 ° C of the stretching temperature, and more preferably in the range of -40 ° C to -10 ° C in the stretching temperature.
而且，延伸步驟S1-2之延伸處理後，可設置熱固定處理步驟。熱固定處理係延伸膜200的端部藉由夾具握持的狀態下，一邊維持拉張狀態，一邊在結晶化溫度以上進行熱處理之處理。藉由該熱固定處理，促進聚乙烯醇系樹脂層6’的結晶化。熱固定處理的溫度為延伸溫度 的-0℃~-80℃的範圍較佳，延伸溫度的-0℃~-50℃的範圍更佳。 Moreover, after extending the extension process of step S1-2, a heat fixation process step may be provided. In the state in which the end portion of the heat-fixing treatment film extension film 200 is held by the jig, the heat treatment is performed at a crystallization temperature or higher while maintaining the stretched state. The crystallization of the polyvinyl alcohol-based resin layer 6' is promoted by the heat setting treatment. The temperature of the heat setting treatment is the extension temperature The range of -0 ° C to -80 ° C is preferred, and the range of -0 ° C to -50 ° C of the extension temperature is better.
[c]染色步驟S1-3 [c] Dyeing step S1-3
參考第6圖，本步驟係將延伸膜200的聚乙烯醇系樹脂層6’以二色性色素染色，使其吸附配向，成為偏光片層5之步驟。經過本步驟，得到偏光片層5積層於基材膜30’的單面或兩面之偏光性積層膜300。作為二色性色素，具體地可使用碘或二色性有機染料。 Referring to Fig. 6, this step is a step of dyeing the polyvinyl alcohol-based resin layer 6' of the stretched film 200 with a dichroic dye to adsorb and align it to form the polarizer layer 5. Through this step, the polarizing layer 5 is laminated on the single-sided or double-sided polarizing laminated film 300 of the base film 30'. As the dichroic dye, specifically, iodine or a dichroic organic dye can be used.
染色步驟可藉由將延伸膜200的整體浸漬於含有二色性色素之溶液(染色溶液)進行。作為染色溶液，可使用上述二色性色素溶解於溶劑之溶液。作為染色溶液的溶劑，一般使用水，但亦可再添加與水具有相溶性之有機溶劑。染色溶液的二色性色素之濃度，較佳為0.01~10重量%，更佳為0.02~7重量%，特別佳為0.025~5重量%。 The dyeing step can be carried out by immersing the entire stretched film 200 in a solution containing a dichroic dye (dyeing solution). As the dyeing solution, a solution in which the above dichroic dye is dissolved in a solvent can be used. As the solvent of the dyeing solution, water is generally used, but an organic solvent compatible with water may be further added. The concentration of the dichroic dye of the dyeing solution is preferably 0.01 to 10% by weight, more preferably 0.02 to 7% by weight, particularly preferably 0.025 to 5% by weight.
於使用碘作為二色性色素時，由於可更進一步提高染色效率，再於含有碘的染色溶液中添加碘化物較佳。作為碘化物，例如碘化鉀、碘化鋰、碘化鈉、碘化鋅、碘化鋁、碘化鉛、碘化銅、碘化鋇、碘化鈣、碘化錫、碘化鈦等。染色溶液的碘化物的濃度較佳為0.01~20重量%。碘化物中，添加碘化鉀較佳。於添加碘化鉀時，碘與碘化鉀的比例，以重量比計，較佳為1：5~1：100的範圍，更佳為1：6~1：80的範圍，特別佳為1：7~1：70的範圍。染色溶液的溫度，較佳為10~60℃的範圍，更佳為20~40 ℃的範圍。 When iodine is used as the dichroic dye, it is preferable to further add iodide to the dye solution containing iodine because the dyeing efficiency can be further improved. Examples of the iodide include potassium iodide, lithium iodide, sodium iodide, zinc iodide, aluminum iodide, lead iodide, copper iodide, cesium iodide, calcium iodide, tin iodide, and titanium iodide. The concentration of the iodide of the dyeing solution is preferably from 0.01 to 20% by weight. Among the iodides, potassium iodide is preferably added. When potassium iodide is added, the ratio of iodine to potassium iodide is preferably in the range of 1:5 to 1:100, more preferably in the range of 1:6 to 1:80, and particularly preferably 1:7 to 1 in terms of weight ratio. : 70 range. The temperature of the dyeing solution is preferably in the range of 10 to 60 ° C, more preferably 20 to 40 The range of °C.
再者，染色步驟S1-3可在延伸步驟S1-2之前進行，該等步驟可同時進行，但為了使其吸附於聚乙烯醇系樹脂層的二色性色素良好地配向，對積層膜100，至少實施某種程度的延伸後，實施染色處理S1-3較佳。亦即，在延伸步驟S1-2實施至成為目標倍率為止的延伸處理所得之延伸膜200，可供應予染色步驟S1-3外，在延伸步驟S1-2進行比目標低的倍率之延伸處理後，染色步驟S1-3中，亦可實施總延伸倍率成為目標倍率的延伸處理。作為後者的實施態樣，例如1)於延伸步驟S1-2，進行比目標低的倍率之延伸處理後，染色步驟S1-3之染色處理中進行總延伸倍率成為目標倍率的延伸處理之態樣；如後述，染色處理後進行交聯處理時，2)於延伸步驟S1-2，進行比目標低的倍率之延伸處理後，染色步驟S1-3之染色處理中進行總延伸倍率至未達目標倍率的延伸處理，然後於交聯處理中進行最終的總延伸倍率成為目標倍率的延伸處理之態樣等。 Further, the dyeing step S1-3 may be performed before the extending step S1-2, and the steps may be performed simultaneously, but in order to properly align the dichroic dye adsorbed to the polyvinyl alcohol-based resin layer, the laminated film 100 After performing at least a certain degree of extension, it is preferred to carry out the dyeing treatment S1-3. In other words, the stretching film 200 obtained by the stretching process until the target magnification is extended in the step S1-2 can be supplied to the dyeing step S1-3, and after the stretching step S1-2 is performed at a magnification lower than the target. In the dyeing step S1-3, the extension processing in which the total stretching ratio becomes the target magnification can also be performed. As an embodiment of the latter, for example, 1) in the extending step S1-2, after the stretching process of the magnification lower than the target, the stretching process in the dyeing step S1-3 is performed in the dyeing process of the dyeing step S1-3. As will be described later, when the cross-linking treatment is performed after the dyeing treatment, 2) after the stretching step of the magnification lower than the target is performed in the extending step S1-2, the total stretching ratio is not reached to the target in the dyeing step of the dyeing step S1-3. The stretching treatment of the magnification is performed, and then the final total stretching ratio becomes the extension processing of the target magnification in the crosslinking treatment.
染色步驟S1-3係可包括染色處理後繼續實施的交聯處理步驟。交聯處理係可藉由將染色的膜浸漬於包含交聯劑的溶液(交聯溶液)中來進行。作為交聯劑，可使用傳統習知的物質，例如硼酸、硼砂等硼化合物、乙二醛、戊二醛等。交聯劑可使用單獨一種，亦可併用2種以上。 The dyeing step S1-3 may include a crosslinking treatment step that is continued after the dyeing treatment. The crosslinking treatment can be carried out by immersing the dyed film in a solution (crosslinking solution) containing a crosslinking agent. As the crosslinking agent, conventionally known materials such as a boron compound such as boric acid or borax, glyoxal, glutaraldehyde or the like can be used. The crosslinking agent may be used alone or in combination of two or more.
交聯溶液具體地為交聯劑溶解於溶劑之溶 液。作為溶劑，例如可使用水，但可更包含與水具有相溶性之有機溶劑。交聯溶液的交聯劑的濃度，較佳為1~20重量%的範圍，更佳為6~15重量%的範圍。 The crosslinking solution is specifically dissolved in a solvent by a crosslinking agent. liquid. As the solvent, for example, water can be used, but an organic solvent compatible with water can be further included. The concentration of the crosslinking agent in the crosslinking solution is preferably in the range of 1 to 20% by weight, more preferably in the range of 6 to 15% by weight.
交聯溶液可包含碘化物。藉由碘化物的添加，偏光片層5的面內的偏光特性可更均勻化。作為碘化物，例如碘化鉀、碘化鋰、碘化鈉、碘化鋅、碘化鋁、碘化鉛、碘化銅、碘化鋇、碘化鈣、碘化錫、碘化鈦等。交聯溶液中的碘化物之濃度為0.05~15重量%較佳，0.5~8重量%更佳。交聯溶液的溫度，較佳為10~90℃的範圍。 The crosslinking solution can comprise an iodide. By the addition of iodide, the in-plane polarization characteristics of the polarizer layer 5 can be more uniform. Examples of the iodide include potassium iodide, lithium iodide, sodium iodide, zinc iodide, aluminum iodide, lead iodide, copper iodide, cesium iodide, calcium iodide, tin iodide, and titanium iodide. The concentration of the iodide in the crosslinking solution is preferably from 0.05 to 15% by weight, more preferably from 0.5 to 8% by weight. The temperature of the crosslinking solution is preferably in the range of 10 to 90 °C.
交聯處理係可藉由調配交聯劑於染色溶液中，亦可與染色處理同時進行。而且，交聯處理中亦可進行延伸處理。交聯處理中實施延伸處理的具體態樣係如上述。而且，使用組成相異的2種以上的交聯溶液，可進行2次以上浸漬於交聯溶液之處理。 The crosslinking treatment can be carried out by mixing a crosslinking agent in the dyeing solution or simultaneously with the dyeing treatment. Moreover, the elongation treatment can also be performed in the crosslinking treatment. The specific aspect in which the elongation treatment is carried out in the crosslinking treatment is as described above. Further, two or more kinds of cross-linking solutions having different compositions can be used for the second or more immersion in the cross-linking solution.
染色步驟S1-3之後，貼合第1保護膜之前，進行洗淨步驟及乾燥步驟為較佳。洗淨步驟通常包括水洗淨步驟。水洗淨處理係可藉由將染色處理後或交聯處理後的膜浸漬於如離子交換水、蒸餾水的純水中進行。水洗淨溫度通常為3~50℃，較佳為4~20℃的範圍。洗淨步驟係亦可為水洗淨步驟與藉由碘化物溶液的洗淨步驟之組合。 After the dyeing step S1-3, it is preferred to perform a washing step and a drying step before bonding the first protective film. The washing step typically includes a water washing step. The water washing treatment can be carried out by immersing the film after the dyeing treatment or the crosslinking treatment in pure water such as ion-exchanged water or distilled water. The water washing temperature is usually from 3 to 50 ° C, preferably from 4 to 20 ° C. The washing step may also be a combination of a water washing step and a washing step by an iodide solution.
作為洗淨步驟後進行的乾燥步驟，可採用如自然乾燥、送風乾燥、加熱乾燥等的任意適合的方法。例如於加熱乾燥時，乾燥溫度通常為20~95℃。 As the drying step performed after the washing step, any suitable method such as natural drying, air drying, heat drying, or the like can be employed. For example, when heated and dried, the drying temperature is usually 20 to 95 °C.
偏光性積層膜300所具有的偏光片層5的厚 度，例如為30μm以下，進一步可為20μm以下，從偏光板的薄型化的觀點，10μm以下較佳，8μm以下更佳。偏光片層5的厚度，通常為2μm以上。 Thickness of the polarizer layer 5 of the polarizing laminated film 300 The degree is, for example, 30 μm or less, and may be 20 μm or less. From the viewpoint of reducing the thickness of the polarizing plate, it is preferably 10 μm or less, more preferably 8 μm or less. The thickness of the polarizer layer 5 is usually 2 μm or more.
於第1保護膜貼合步驟S10中，參考第7圖，於上述偏光性積層膜300的偏光片層5上，隔著接著劑層15，貼合水分率調整為比25℃ 55% RH(相對濕度)的平衡水分率高之第1保護膜10，得到附有保護膜的偏光性積層膜400之步驟。 In the first protective film bonding step S10, referring to Fig. 7, on the polarizing plate layer 5 of the polarizing laminated film 300, the adhesion ratio is adjusted to be 55% RH at 25 ° C via the adhesive layer 15 ( The first protective film 10 having a high moisture content and a high moisture content is obtained by a step of obtaining a polarizing laminated film 400 with a protective film.
所謂保護膜的「25℃ 55% RH的平衡水分率」，係指在25℃ 55% RH環境下放置24小時時的水分率。保護膜的水分率係藉由乾燥重量法求得，具體地於105℃、120分鐘的熱處理前後的保護膜重量分別設為W0、W1時，由下述式：水分率(wt/wt%)=100×(W0-W1)/W0求得。 The "25 ° C 55% RH equilibrium moisture content" of the protective film refers to the water content when placed in a 55% RH atmosphere at 25 ° C for 24 hours. The moisture content of the protective film is determined by the dry weight method. Specifically, when the weights of the protective films before and after the heat treatment at 105 ° C for 120 minutes are respectively set to W 0 and W 1 , the following formula: moisture ratio (wt/wt) %) = 100 × (W 0 - W 1 ) / W 0 is obtained.
如上述的具有指定的水分率的第1保護膜10，維持該指定的水分率的狀態下，藉由貼合於偏光性積層膜300的偏光片層5，可有效地抑制經過剝離除去基材膜30’的剝離步驟S20所製造的偏光板(如前述，此處所謂的偏光板，係指包含偏光片層以及隔著接著劑層積層於其至少一側的面之保護膜者)的捲曲。 When the first protective film 10 having the specified moisture content is maintained in the predetermined moisture content, the polarizing layer 5 bonded to the polarizing laminate film 300 can be effectively prevented from being removed by peeling off. The polarizing plate produced by the peeling step S20 of the film 30' (as described above, the polarizing plate refers to a protective film including a polarizing plate layer and a surface on which at least one side of the adhesive layer is laminated) .
此處，進一步說明關於偏光板的捲曲及本發明的捲曲抑制效果。所謂捲曲(curl)，係指如偏光板的膜(包括積層膜)彎曲成弓狀(或顯著的情況為筒狀)的現象。若 是關於偏光片層5的一側的面，隔著接著劑層15貼合第1保護膜10所成的單面附有保護膜的偏光板，第1保護膜10側設為內側而捲曲的狀態稱為正捲曲，偏光片層5側設為內側而捲曲之狀態稱為逆捲曲。 Here, the curling of the polarizing plate and the curl suppressing effect of the present invention are further explained. The term "curl" refers to a phenomenon in which a film (including a laminated film) such as a polarizing plate is bent into a bow shape (or a tubular shape in a remarkable case). If In the surface of one side of the polarizer layer 5, a polarizing plate having a protective film on one side of the first protective film 10 is bonded to the first protective film 10 via the adhesive layer 15, and the side of the first protective film 10 is curled inside. The state is referred to as positive curl, and the state in which the side of the polarizer layer 5 is set to the inside and curled is referred to as reverse curl.
於偏光板，捲曲成為問題係於液晶胞等顯示胞隔著黏著劑層貼合偏光板時，該偏光板產生捲曲的情況。亦即，貼合於液晶胞等顯示胞時，偏光板通常貼合有各種膜、層的其他周邊構件而成為複合偏光板，於該複合偏光板中，必須抑制捲曲。作為周邊構件，例如貼合於保護膜上的防止刮傷用保護膜；積層於保護膜上(例如兩面附有保護膜的偏光板時)或偏光片層上(例如單面附有保護膜的偏光板時)之偏光板貼合於液晶胞、其他光學構件用之黏著劑層；積層於黏著劑層的外面的離型膜；積層於保護膜上(例如兩面附有保護膜的偏光板時)或偏光片層上(例如單面附有保護膜的偏光板時)之如相位差膜的光學補償膜、其他光學功能性膜；積層於保護膜上的表面處理層等。 In the case of a polarizing plate, curling is a problem in that when a display cell such as a liquid crystal cell is attached to a polarizing plate via an adhesive layer, the polarizing plate is curled. In other words, when the display cell is bonded to a display cell such as a liquid crystal cell, the polarizing plate is usually laminated with other peripheral members of various films and layers to form a composite polarizing plate. In the composite polarizing plate, it is necessary to suppress curling. As a peripheral member, for example, a protective film for scratch prevention attached to a protective film; laminated on a protective film (for example, when a polarizing plate having a protective film is attached) or a polarizing layer (for example, a protective film is attached to one side) The polarizing plate of the polarizing plate is bonded to the liquid crystal cell and the adhesive layer for other optical members; the release film laminated on the outer surface of the adhesive layer; and laminated on the protective film (for example, when the polarizing plate with the protective film is attached on both sides) Or an optical compensation film such as a retardation film, another optical functional film, a surface treatment layer laminated on the protective film, or the like on the polarizing plate layer (for example, when a polarizing plate having a protective film is provided on one side).
複合偏光板為不捲曲、平坦的，或複合偏光板所具有的黏著劑層側設為外側(凸)，有些許捲曲剛剛好。藉此，貼合複合偏光板於顯示胞時，於黏著劑層與顯示胞之間，可抑制氣泡混入，可抑制顯示裝置上產生顯示上的缺陷、貼合面的端部產生不良的缺陷。相反地，若是黏著劑層側設為內側(凹)而複合偏光板捲曲時，貼合時容易咬入氣泡，發生上述缺陷的可能性高。 The composite polarizing plate is not curled and flat, or the side of the adhesive layer of the composite polarizing plate is set to the outer side (convex), and the curl is just right. As a result, when the composite polarizing plate is bonded to the display cell, air bubbles can be prevented from entering between the adhesive layer and the display cell, and defects in display on the display device and defects in the end portion of the bonding surface can be suppressed. On the other hand, when the side of the adhesive layer is set to the inner side (concave) and the composite polarizing plate is curled, it is easy to bite into the air during bonding, and the possibility of occurrence of the above-mentioned defects is high.
貼合周邊構件時，企圖抑制複合偏光板的 捲曲量，矯正捲曲的方向雖有可能，但仍然在保護膜貼合於偏光片層的至少一側的面所成的偏光板的狀態下，必須捲曲小，否則難以控制複合偏光板的捲曲。因此，必須控制保護膜貼合於偏光片層的至少一側的面所成的偏光板本身的捲曲。 Attempting to suppress the composite polarizer when fitting the peripheral members Although the amount of curling and the direction of correcting the curl are possible, in the state where the protective film is bonded to the polarizing plate formed on at least one side of the polarizing plate layer, the curl must be small, and it is difficult to control the curl of the composite polarizing plate. Therefore, it is necessary to control the curl of the polarizing plate itself which is formed by bonding the protective film to the surface of at least one side of the polarizing plate layer.
亦即，保護膜貼合於偏光片層的至少一側的面所成的偏光板的捲曲，無論正捲曲或逆捲曲，較佳為藉由周邊構件的貼合而縮小至可矯正的程度，更佳為儘可能地平坦。若根據本發明，可實現此。特別是於傳統的塗佈法中，保護膜貼合於偏光片層後，剝離除去基材膜時，所得之偏光板於逆捲曲的方向有捲曲大的傾向，若根據本發明，特別可有效地抑制該逆捲曲。 In other words, the curl of the polarizing plate formed by bonding the protective film to at least one side of the polarizer layer is preferably reduced to a degree that can be corrected by the bonding of the peripheral members, regardless of the curl or the reverse curl. Better to be as flat as possible. This can be achieved according to the invention. In particular, in the conventional coating method, when the protective film is bonded to the polarizer layer and the base film is peeled off, the obtained polarizing plate tends to have a large curl in the direction of the reverse crimp, and is particularly effective according to the present invention. This reverse curl is suppressed.
於傳統的塗佈法中，容易產生逆捲曲，認為是基材膜的拘束力發揮作用。認為於藉由塗佈法所形成的偏光性積層膜中，偏光片層係由於基材膜的剛性成為未收縮的狀態，保護膜貼合後，剝離除去基材膜時，於偏光片層產生收縮。再者，相對於此，於包含單體(單獨)膜的偏光片(偏光膜)隔著接著劑層貼合保護膜的單體膜法時，保護膜貼合前，以水分蒸發、乾燥、張力控制等，因偏光片充分收縮，故保護膜貼合後，偏光片不會引起這麼多的尺寸變化，最初捲曲的問題不易產生。 In the conventional coating method, reverse curl is likely to occur, and it is considered that the binding force of the base film acts. In the polarizing laminate film formed by the coating method, the polarizer layer is in an uncontracted state due to the rigidity of the base film, and when the protective film is bonded, the base film is peeled off and the polarizing sheet is produced. shrink. In contrast, when a polarizing film (polarizing film) containing a monomer (separate) film is bonded to a single film method of a protective film via an adhesive layer, water is evaporated and dried before the protective film is bonded. Tension control, etc., because the polarizer is sufficiently shrunk, the polarizer does not cause so many dimensional changes after the protective film is bonded, and the problem of initial curling is less likely to occur.
藉由將具有水分率比25℃ 55% RH的平衡水分率高之第1保護膜10，貼合於偏光性積層膜300的偏光片層5後，剝離除去基材膜30’的本發明的方法，可有效 地抑制逆捲曲，推測為以下的理由。亦即，具有比上述平衡水分率高的水分率之第1保護膜10，於貼合時，其尺寸稍稍膨脹變大，該狀態的第1保護膜10貼合於偏光片層5時，其後通常的環境(貼合後的製造步驟的環境、所得之偏光板的保存環境、偏光板對顯示胞貼合時的環境)為25℃ 55% RH的環境下，第1保護膜10欲收縮的力(恢復至25℃ 55% RH的環境下的尺寸之力)，換言之，欲矯正成正捲曲方向的力作用。該力抑制逆捲曲。 The first protective film 10 having a water content ratio of 55% RH and an equilibrium moisture content is bonded to the polarizing layer 5 of the polarizing laminated film 300, and the base film 30' is peeled off. Method can be effective The reason for suppressing the reverse curl is presumed to be the following reason. In other words, the first protective film 10 having a moisture content higher than the above-described equilibrium moisture content has a slight expansion in size when bonded, and when the first protective film 10 in this state is bonded to the polarizer layer 5, After the normal environment (the environment of the manufacturing step after bonding, the storage environment of the obtained polarizing plate, and the environment when the polarizing plate is bonded to the display cell) is 25 ° C, 55% RH, the first protective film 10 is intended to shrink. The force (returns to the size of the environment at 25 ° C 55% RH), in other words, the force to be corrected in the direction of positive curl. This force suppresses the inverse curl.
第1保護膜10的水分率太高時，朝正捲曲方向的捲曲變強，容易產生氣泡混入的缺陷，而且於放置於嚴苛的環境下時，進一步助長正捲曲，偏光板的端部恐會從顯示胞剝離。所以，貼合於偏光片層5上的第1保護膜10的水分率，較佳為其飽和水分率的70%以下，更佳為60%以下。所謂飽和水分率，係指將第1保護膜10浸漬於30℃的水3小時，除去表面的附著水而測定時的水分率，水分率的定義如前述。 When the moisture content of the first protective film 10 is too high, the curl in the positive crimping direction becomes strong, and the defects of air bubbles are likely to occur, and when it is placed in a severe environment, the curl is further promoted, and the end of the polarizing plate is feared. Will peel off from the display cells. Therefore, the moisture content of the first protective film 10 bonded to the polarizer layer 5 is preferably 70% or less, more preferably 60% or less. The saturated water content is a water content measured by immersing the first protective film 10 in water at 30° C. for 3 hours to remove adhering water on the surface, and the water content is defined as described above.
調製具有水分率比25℃ 55% RH的平衡水分率高之第1保護膜10的方法，無特別限制，例如在可調整溫濕度的調濕槽內，將保護膜放置一定時間的方法。作為調濕槽，可使用市售的調濕箱、空調設備。 The method of preparing the first protective film 10 having a water content ratio higher than the equilibrium moisture ratio of 55% RH at 25° C. is not particularly limited. For example, a method in which the protective film is left for a predetermined period of time in a humidity control tank capable of adjusting temperature and humidity. As the humidity control tank, a commercially available humidity control box or an air conditioner can be used.
而且，作為其他方法，亦可適合使用一度於水浴中通過保護膜，水分率過高後，使其乾燥的方法。該方法，因可在短時間調整水分率至所期望的值，適合於連續生產而提高生產性。藉由調整對水浴的滯留時間、水 溫，可簡便地調整最初的水分率外，藉由乾燥時間、乾燥溫度，亦可調整最終的水分率。水浴例如可為單純的儲存溫水的槽，可調整水浴溫度而使維持該溫度於一定者較佳。取代水浴的使用，亦可採用對保護膜吹蒸氣的方法；藉由噴霧法等吹水氣的方法；以塗佈機等塗佈水的方法。 Further, as another method, a method in which the protective film is once passed through a water bath and the moisture content is too high may be suitably used. This method is suitable for continuous production and improves productivity because the moisture content can be adjusted to a desired value in a short time. By adjusting the residence time of the water bath, water In addition, the initial moisture content can be easily adjusted, and the final moisture content can be adjusted by drying time and drying temperature. The water bath may be, for example, a tank for storing warm water, and the temperature of the water bath may be adjusted to maintain the temperature at a certain level. Instead of the use of the water bath, a method of blowing steam to the protective film, a method of blowing water by a spray method or the like, or a method of applying water by a coater or the like may be employed.
乾燥的方法，可為任意的方法，例如吹熱風，使用所謂熱風乾燥爐的乾燥、藉由紅外線加熱器的乾燥等。抑制急速的水分率降低，為了緩和地實施乾燥，以調整乾燥爐內的濕度為較佳。 The drying method may be any method such as blowing hot air, drying using a so-called hot air drying oven, drying by an infrared heater, or the like. It is preferable to suppress the rapid decrease in the moisture content and to adjust the humidity in the drying furnace in order to carry out the drying gently.
構成第1保護膜10的材料，具有透光性(較佳為光學透明)的熱塑性樹脂較佳，作為如此的樹脂，例如鏈狀聚烯烴系樹脂(聚丙烯系樹脂等)、環狀聚烯烴系樹脂(降莰烯系樹脂等)之聚烯烴系樹脂；如纖維素三乙酸酯、纖維素二乙酸酯之纖維素酯系樹脂；聚酯系樹脂；聚碳酸酯系樹脂；(甲基)丙烯酸系樹脂；聚苯乙烯系樹脂；或該等的混合物、共聚物等。 The material constituting the first protective film 10 is preferably a translucent (preferably optically transparent) thermoplastic resin, and such a resin is, for example, a chain polyolefin resin (such as a polypropylene resin) or a cyclic polyolefin. a polyolefin resin such as a resin (northene-based resin); a cellulose ester resin such as cellulose triacetate or cellulose diacetate; a polyester resin; a polycarbonate resin; Acrylic resin; polystyrene resin; or such mixtures, copolymers, and the like.
本發明的方法，採用以保護膜的25℃ 55% RH的平衡含水率為基準，調整水分率為指定的值的手段，而謀求抑制捲曲，故無論保護膜的種類，有可抑制所得之偏光板的捲曲的優點。其中，使用纖維素酯系樹脂(例如纖維素三乙酸酯)、(甲基)丙烯酸系樹脂(例如聚甲基丙烯酸甲酯樹脂)的透濕度高之保護膜時，因水分率的變化造成的尺寸差異大，故於正捲曲方向，矯正的力大，本發明的優點大。 In the method of the present invention, the method of adjusting the water content to a predetermined value based on the equilibrium moisture content of the protective film at 25 ° C and 55% RH is used, and the curl is suppressed. Therefore, the obtained polarized light can be suppressed regardless of the type of the protective film. The advantage of the curl of the board. Among them, when a protective film having a high moisture permeability of a cellulose ester resin (for example, cellulose triacetate) or a (meth)acrylic resin (for example, polymethyl methacrylate resin) is used, the moisture content changes. The difference in size is large, so that the positive curling direction and the correcting force are large, and the advantages of the present invention are large.
第1保護膜10亦可為合併具有如相位差膜、增亮膜的光學功能的保護膜。例如使上述熱塑性樹脂所成的膜進行延伸(一軸延伸或二軸延伸等)，藉由於該膜上形成液晶層等，可成為賦予任意相位差值的相位差膜。 The first protective film 10 may also be a protective film incorporating an optical function such as a retardation film or a brightness enhancement film. For example, the film formed of the thermoplastic resin is stretched (one-axis stretching or biaxial stretching, etc.), and a liquid crystal layer or the like is formed on the film to form a retardation film which imparts an arbitrary retardation value.
作為鏈狀聚烯烴系樹脂，除如聚乙烯樹脂、聚丙烯樹脂的鏈狀烯烴的均聚物外，可舉例如包含2種以上的鏈狀烯烴的共聚物。 In addition to a homopolymer of a chain olefin such as a polyethylene resin or a polypropylene resin, a copolymer of two or more kinds of chain olefins may be mentioned as the chain polyolefin resin.
環狀聚烯烴系樹脂係以環狀烯烴為聚合單元而聚合的樹脂之總稱。列舉環狀聚烯烴系樹脂的具體例時，有環狀烯烴的開環(共)聚合物、環狀烯烴的加成聚合物、環狀烯烴與如乙烯、丙烯的鏈狀烯烴的共聚物(代表為無規共聚物)及該等以不飽和羧酸、其衍生物改性的接枝共聚物以及該等的氫化物等。其中，使用降莰烯、多環降莰烯系單體等的降莰烯系單體作為環狀烯烴之降莰烯系樹脂較宜使用。 The cyclic polyolefin resin is a general term for a resin obtained by polymerizing a cyclic olefin as a polymerization unit. Specific examples of the cyclic polyolefin-based resin include a ring-opened (co)polymer of a cyclic olefin, an addition polymer of a cyclic olefin, and a copolymer of a cyclic olefin and a chain olefin such as ethylene or propylene ( Representative of a random copolymer) and such graft copolymers modified with unsaturated carboxylic acids and derivatives thereof, and such hydrides and the like. Among them, a norbornene-based resin having a norbornene-based monomer such as a norbornene or a polycyclic norbornene-based monomer as a cyclic olefin is preferably used.
纖維素酯系樹脂係纖維素與脂肪酸的酯。作為纖維素酯系樹脂的具體例，包括纖維素三乙酸酯、纖維素二乙酸酯、纖維素三丙酸酯、纖維素二丙酸酯。而且，可使用該等的共聚物、羥基的一部分以其他取代基修飾者。該等之中，特別佳為纖維素三乙酸酯(三乙醯基纖維素：TAC)。 The cellulose ester resin is an ester of cellulose and a fatty acid. Specific examples of the cellulose ester-based resin include cellulose triacetate, cellulose diacetate, cellulose tripropionate, and cellulose dipropionate. Further, these copolymers may be used, and a part of the hydroxyl group may be modified with other substituents. Among these, cellulose triacetate (triethylenesulfonyl cellulose: TAC) is particularly preferred.
聚酯系樹脂為具有酯鍵結之樹脂，一般為多價羧酸或其衍生物與多元醇的縮聚物所成者。作為多價羧酸或其衍生物，可使用2價的二羧酸或其衍生物，例如 對苯二甲酸、間苯二甲酸、對苯二甲酸二甲酯、萘二羧酸二甲酯等。作為多元醇，可使用2元的二醇，例如乙二醇、丙二醇、丁二醇、新戊二醇、環己二甲醇等。 The polyester resin is a resin having an ester bond, and is generally a polycondensate of a polyvalent carboxylic acid or a derivative thereof and a polyhydric alcohol. As the polyvalent carboxylic acid or a derivative thereof, a divalent dicarboxylic acid or a derivative thereof can be used, for example Terephthalic acid, isophthalic acid, dimethyl terephthalate, dimethyl naphthalene dicarboxylate, and the like. As the polyol, a divalent diol such as ethylene glycol, propylene glycol, butanediol, neopentyl glycol, cyclohexanedimethanol or the like can be used.
聚酯系樹脂的具體例，包括聚對苯二甲酸二乙酯、聚對苯二甲酸二丁酯、聚萘二甲酸二乙酯、聚萘二甲酸二丁酯、聚對苯二甲酸二丙酯、聚萘二甲酸二丙酯、聚對苯二甲酸環己基二甲酯、聚萘二甲酸環己基二甲酯。 Specific examples of the polyester resin include polyethylene terephthalate, polybutylene terephthalate, polyethylene naphthalate, dibutyl naphthalate, and dibutyl terephthalate. Ester, dipolyethylene naphthalate, cyclohexyl dimethyl terephthalate, cyclohexyl dimethyl naphthalate.
聚碳酸酯系樹脂為包含隔著碳酸酯基鍵結單體單元之聚合物。聚碳酸酯系樹脂亦可為修飾聚合物骨架之被稱為改性聚碳酸酯的樹脂、共聚合聚碳酸酯等。 The polycarbonate resin is a polymer containing a monomer unit bonded via a carbonate group. The polycarbonate resin may be a resin called a modified polycarbonate or a copolymerized polycarbonate which modifies a polymer skeleton.
(甲基)丙烯酸系樹脂係具有(甲基)丙烯醯基的化合物為主要構成單體之樹脂。(甲基)丙烯酸系樹脂的具體例，例如包括如聚甲基丙烯酸甲酯之聚(甲基)丙烯酸酯；甲基丙烯酸甲酯-(甲基)丙烯酸共聚物；甲基丙烯酸甲酯-(甲基)丙烯酸酯共聚物；甲基丙烯酸甲酯-丙烯酸酯-(甲基)丙烯酸共聚物；(甲基)丙烯酸甲酯-苯乙烯共聚物(MS樹脂等)；甲基丙烯酸甲酯與具有脂環族烴基的化合物之共聚物(例如甲基丙烯酸甲酯-甲基丙烯酸環己酯共聚物、甲基丙烯酸甲酯-(甲基)丙烯酸降莰酯共聚物等)。較佳為使用如聚(甲基)丙烯酸甲酯之聚(甲基)丙烯酸C1-6烷酯為主成分的聚合物，更佳為使用甲基丙烯酸甲酯為主成分(50~100重量%，較佳為70~100重量%)之甲基丙烯酸甲酯系樹脂。 The (meth)acrylic resin is a resin having a (meth)acryloyl group as a main constituent monomer. Specific examples of the (meth)acrylic resin include, for example, poly(meth)acrylate such as polymethyl methacrylate; methyl methacrylate-(meth)acrylic acid copolymer; methyl methacrylate-( Methyl) acrylate copolymer; methyl methacrylate-acrylate-(meth)acrylic acid copolymer; methyl (meth) acrylate-styrene copolymer (MS resin, etc.); methyl methacrylate and A copolymer of an alicyclic hydrocarbon group-containing compound (for example, methyl methacrylate-cyclohexyl methacrylate copolymer, methyl methacrylate-methyl (meth) acrylate), and the like. It is preferably a polymer containing a poly(meth)acrylic acid C 1-6 alkyl ester such as poly(methyl) acrylate as a main component, and more preferably a methyl methacrylate as a main component (50 to 100 weight). %, preferably 70 to 100% by weight of a methyl methacrylate-based resin.
再者，以上所示的各熱塑性樹脂的說明，亦可應用於構成基材膜30的熱塑性樹脂。 Further, the description of each of the thermoplastic resins shown above can also be applied to the thermoplastic resin constituting the base film 30.
第1保護膜10的與偏光片層5相反側的表面，亦可形成如硬塗層、防眩層、抗反射層、抗靜電層、防污層之表面處理層(塗覆層)。於保護膜表面形成表面處理層的方法，無特別限制，可使用習知的方法。 The surface of the first protective film 10 on the side opposite to the polarizer layer 5 may be a surface treatment layer (coating layer) such as a hard coat layer, an antiglare layer, an antireflection layer, an antistatic layer, or an antifouling layer. The method of forming the surface treatment layer on the surface of the protective film is not particularly limited, and a conventional method can be used.
第1保護膜10的厚度，從偏光板的薄型化的觀點，薄者較佳，太薄時，強度降低，加工性變差。因此，第1保護膜10的厚度，較佳為5~90μm，更佳為5~60μm，更加佳為5~50μm。 The thickness of the first protective film 10 is preferably thinner from the viewpoint of thinning of the polarizing plate, and when it is too thin, the strength is lowered and the workability is deteriorated. Therefore, the thickness of the first protective film 10 is preferably 5 to 90 μm, more preferably 5 to 60 μm, still more preferably 5 to 50 μm.
上述經調整水分率所成的第1保護膜10，隔著接著劑層15，積層於偏光性積層膜300的偏光片層5上(偏光片層5的與基材膜30’相反側的面)。偏光性積層膜300於基材膜30’的兩面具有偏光片層5時，於兩面的偏光片層5上，分別貼合保護膜。此時，該等保護膜，可為相同種類的保護膜，亦可為不同種類的保護膜。 The first protective film 10 formed by the adjusted moisture content is laminated on the polarizer layer 5 of the polarizing laminate film 300 via the adhesive layer 15 (the surface of the polarizer layer 5 opposite to the base film 30') ). When the polarizing film layer 3 has the polarizing plate layer 5 on both surfaces of the base film 30', the protective film is bonded to the polarizing plate layer 5 on both surfaces. In this case, the protective films may be the same type of protective film or different types of protective films.
第1保護膜10貼合於偏光片層5上時，於第1保護膜10的貼合面，為了提高與偏光片層5的接著性，可進行電漿處理、電暈處理、紫外線照射處理、火焰(flame)處理、皂化處理等的表面處理(易接著處理)，其中，進行電漿處理、電暈處理或皂化處理較佳。例如第1保護膜10為包含環狀聚烯烴系樹脂時，通常進行電漿處理、電暈處理。而且於包含纖維素系樹脂時，通常進行皂化處理。作為皂化處理，例如浸漬於如氫氧化鈉、氫氧化鉀之鹼水溶液之方法。 When the first protective film 10 is bonded to the polarizer layer 5, the bonding surface of the first protective film 10 can be subjected to plasma treatment, corona treatment, or ultraviolet irradiation treatment in order to improve adhesion to the polarizer layer 5. A surface treatment (easily followed by treatment) such as a flame treatment or a saponification treatment, wherein a plasma treatment, a corona treatment or a saponification treatment is preferred. For example, when the first protective film 10 contains a cyclic polyolefin resin, it is usually subjected to plasma treatment or corona treatment. Further, when a cellulose-based resin is contained, it is usually subjected to a saponification treatment. As the saponification treatment, for example, a method of immersing in an aqueous alkali solution such as sodium hydroxide or potassium hydroxide.
作為貼合所使用的接著劑，可使用水系接 著劑、光硬化性接著劑。作為水系接著劑，例如包含聚乙烯醇系樹脂水溶液的接著劑、水系二液型胺基甲酸乙酯系乳化接著劑等。特別是使用以皂化處理等表面處理(親水化處理)過的纖維素酯系樹脂膜作為第1保護膜10時，使用包含聚乙烯醇系樹脂水溶液的水系接著劑較佳。 As a bonding agent used for bonding, water connection can be used. A coating agent and a photocurable adhesive. The water-based adhesive is, for example, an adhesive containing a polyvinyl alcohol-based resin aqueous solution, an aqueous two-liquid urethane-based emulsified adhesive, or the like. In particular, when a cellulose ester-based resin film which has been subjected to surface treatment (hydrophilization treatment) such as saponification treatment is used as the first protective film 10, a water-based adhesive containing a polyvinyl alcohol-based resin aqueous solution is preferably used.
作為聚乙烯醇系樹脂，除乙酸乙烯酯的均聚物之聚乙酸乙烯酯皂化處理所得之乙烯醇同元聚合物外，可使用乙酸乙烯酯及可與其共聚合之其他單體的共聚物皂化處理所得之聚乙烯醇共聚物或該等的羥基部分改性的改性聚乙烯醇系聚合物等。水系接著劑可包括多價醛、水溶性環氧化合物、三聚氰胺系化合物、氧化鋯化合物、鋅化合物等的添加劑。 As the polyvinyl alcohol-based resin, in addition to the vinyl alcohol homopolymer obtained by the polyvinyl acetate saponification treatment of the homopolymer of vinyl acetate, saponification of a copolymer of vinyl acetate and other monomers copolymerizable therewith can be used. The obtained polyvinyl alcohol copolymer or the modified hydroxy group-modified modified polyvinyl alcohol polymer or the like is treated. The aqueous binder may include an additive such as a polyvalent aldehyde, a water-soluble epoxy compound, a melamine-based compound, a zirconia compound, a zinc compound or the like.
將水系接著劑塗佈於偏光性積層膜300的偏光片層5及/或第1保護膜10的貼合面，該等膜隔著接著劑層貼合，較佳為實施使用貼合滾輪等藉由加壓密合而貼合的步驟。水系接著劑(光硬化性接著劑也相同)的塗佈方法，無特別限制，可使用流鑄法、邁耶(Meyer)棒塗法、凹版塗佈法、缺角輪塗佈法、刮刀塗佈法、狹縫塗佈法、浸塗法、噴霧法等傳統習知的方法。 The water-based adhesive is applied to the bonding surface of the polarizing plate layer 5 of the polarizing laminated film 300 and/or the first protective film 10, and the films are bonded to each other via the adhesive layer, and it is preferable to use a bonding roller or the like. The step of bonding by press-fitting. The coating method of the water-based adhesive (the same applies to the photocurable adhesive) is not particularly limited, and a cast molding method, a Meyer bar coating method, a gravure coating method, a notch wheel coating method, or a doctor blade coating method can be used. Traditionally known methods such as cloth coating, slit coating, dip coating, and spray coating.
於使用水系接著劑時，實施上述貼合後，為了除去包含於水系接著劑中的水，實施乾燥膜的乾燥步驟較佳。乾燥係例如可藉由將膜導入乾燥爐而進行。乾燥溫度較佳為30~90℃。未達30℃時，第1保護膜10容易從偏光片層5剝離。乾燥溫度超過90℃時，由於熱，偏光片 層5的偏光性能恐會劣化。 When the water-based adhesive is used, after the above-mentioned bonding, in order to remove the water contained in the aqueous binder, the drying step of drying the film is preferred. The drying system can be carried out, for example, by introducing the film into a drying furnace. The drying temperature is preferably from 30 to 90 °C. When the temperature is less than 30 ° C, the first protective film 10 is easily peeled off from the polarizer layer 5 . When the drying temperature exceeds 90 ° C, due to heat, polarizer The polarizing performance of the layer 5 may be deteriorated.
乾燥步驟後，亦可設置在室溫或比其稍微高的溫度，例如20~45℃程度的溫度下熟化之熟化步驟。熟化溫度一般設定為比乾燥溫度更低。 After the drying step, a ripening step at room temperature or a slightly higher temperature, for example, a temperature of about 20 to 45 ° C may be provided. The curing temperature is generally set to be lower than the drying temperature.
所謂光硬化性接著劑，係指藉由照射如紫外線的活性能量線而硬化的接著劑，例如包括聚合性化合物及光聚合引發劑者、包括光反應性樹脂者、包括黏結劑樹脂及光反應性交聯劑者等。作為聚合性化合物，例如光硬化性環氧系單體、光硬化性丙烯酸系單體、光硬化性胺基甲酸乙酯系單體的光聚合性單體、來自光聚合性單體的寡聚物。作為光聚合引發劑，例如包括藉由如紫外線的活性能量線的照射而產生如中性自由基、陰離子自由基、陽離子自由基的活性物種的物質者。作為包含聚合性化合物及光聚合引發劑的光硬化性接著劑，較佳為使用包含光硬化性環氧系單體及光陽離子聚合引發劑者。 The photocurable adhesive refers to an adhesive which is cured by irradiation with an active energy ray such as ultraviolet rays, for example, a polymerizable compound and a photopolymerization initiator, a photoreactive resin, a binder resin, and a photoreaction. Sex cross-linkers, etc. The polymerizable compound is, for example, a photocurable epoxy monomer, a photocurable acrylic monomer, a photocurable monomer of a photocurable urethane monomer, or an oligomer derived from a photopolymerizable monomer. Things. As the photopolymerization initiator, for example, a substance which generates an active species such as a neutral radical, an anionic radical, or a cationic radical by irradiation with an active energy ray such as ultraviolet rays is included. As the photocurable adhesive containing a polymerizable compound and a photopolymerization initiator, those containing a photocurable epoxy monomer and a photocationic polymerization initiator are preferably used.
於使用光硬化性接著劑時，實施上述貼合後，依據需要，進行乾燥步驟(於光硬化性接著劑包含溶劑時等)，然後，進行藉由照射活性能量線而使光硬化性接著劑硬化的硬化步驟。活性能量線的光源，無特別限制，較佳為具有波長400nm以下的發光分佈之活性能量線，具體地使用低壓水銀燈、中壓水銀燈、高壓水銀燈、超高壓水銀燈、化學燈、黑光燈、微波激發水銀燈、金屬鹵化物燈等較佳。 When the photocurable adhesive is used, after the above-mentioned bonding, the drying step is carried out as needed (when the photocurable adhesive contains a solvent), and then the photocurable adhesive is applied by irradiation with an active energy ray. Hardening hardening step. The light source of the active energy ray is not particularly limited, and is preferably an active energy ray having a light-emitting distribution with a wavelength of 400 nm or less, specifically, a low-pressure mercury lamp, a medium-pressure mercury lamp, a high-pressure mercury lamp, an ultra-high pressure mercury lamp, a chemical lamp, a black lamp, and microwave excitation. Mercury lamps, metal halide lamps and the like are preferred.
〈剝離步驟S20〉 <Peeling step S20>
參考第8圖，本步驟係於第1保護膜貼合步驟S10後，剝離除去基材膜30’的步驟。以本步驟，得到單面附有保護膜的偏光板1。偏光性積層膜300係於基材膜30’的兩面具有偏光片層5，於該等二偏光片層5貼合有保護膜時，藉由該剝離步驟S20，從1片偏光性積層膜300，可得到2片單面附有保護膜的偏光板1。 Referring to Fig. 8, this step is a step of peeling off the base film 30' after the first protective film bonding step S10. In this step, a polarizing plate 1 having a protective film on one side is obtained. The polarizing laminate film 300 has a polarizer layer 5 on both surfaces of the base film 30', and when the protective film is bonded to the polarizer layer 5, the polarizing film 300 is removed from the polarizing film 300 by the peeling step S20. Two polarizing plates 1 with a protective film on one side are obtained.
剝離除去基材膜30’的方法，無特別限制，可以與通常附有黏著劑的偏光板所進行的分隔片(離型膜)的剝離步驟相同的方法剝離。基材膜30’係在第1保護膜貼合步驟S10後，可直接立即剝離，亦可於第1保護膜貼合步驟S10後，一度捲取成捲狀，在其後的步驟一邊捲出一邊剝離。 The method of peeling off the base film 30' is not particularly limited, and it can be peeled off in the same manner as the peeling step of the separator (release film) by the polarizing plate to which the adhesive is usually applied. After the first protective film bonding step S10, the base film 30' may be directly peeled off immediately, or may be wound into a roll once after the first protective film bonding step S10, and rolled out in the subsequent steps. Stripped on one side.
〈第2保護膜貼合步驟S30〉 <Second protective film bonding step S30>
參考第3圖及第9圖，於單面附有保護膜的偏光板1的偏光片層5側的面，隔著接著劑層25，貼合第2保護膜20之本步驟實施時，可得到兩面附有保護膜的偏光板2。關於第2保護膜20及貼合其之接著劑層25，引用第1保護膜10及接著劑層25所述的記載。第1保護膜10及第2保護膜20，可互為同種類的保護膜，亦可為不同種類的保護膜。接著劑層15及接著劑層25可由互相同種類的接著劑所形成，亦可由不同種類的接著劑所形成。 Referring to FIGS. 3 and 9, the surface of the polarizing plate 1 on the side of the polarizing plate 1 having the protective film on one side thereof can be bonded to the surface of the second protective film 20 via the adhesive layer 25, A polarizing plate 2 having a protective film on both sides was obtained. The description of the first protective film 10 and the adhesive layer 25 is referred to as the second protective film 20 and the adhesive layer 25 to which the adhesive film 20 is bonded. The first protective film 10 and the second protective film 20 may be the same type of protective film, or may be different types of protective films. The adhesive layer 15 and the adhesive layer 25 may be formed of the same kind of adhesives, or may be formed of different kinds of adhesives.
與第1保護膜10同樣地，若使用已調整水分率的亦即具有水分率比25℃ 55% RH的平衡水分率高之第2保護膜20，可進一步改善兩面附有保護膜的偏光板2 的捲曲。 In the same manner as the first protective film 10, if the second protective film 20 having a moisture content higher than the equilibrium moisture ratio of 25 ° C and 55% RH is used, the polarizing plate with the protective film on both sides can be further improved. 2 Curl.
如前述，所得之單面附有保護膜的偏光板1、兩面附有保護膜的偏光板2，係可貼合上述例示的周邊構件而成為複合偏光板，或可使用作為如此的複合偏光板。 As described above, the obtained polarizing plate 1 having a protective film on one side and the polarizing plate 2 having a protective film on both sides thereof can be bonded to the above-exemplified peripheral member to form a composite polarizing plate, or can be used as such a composite polarizing plate. .
周邊構件的一例之黏著劑層，係於兩面附有保護膜的偏光板2時，可積層於任一保護膜的外面，於單面附有保護膜的偏光板1時，例如可積層於偏光片層的與保護膜相反側的面。形成黏著劑層的黏著劑，通常係由(甲基)丙烯酸系樹脂、苯乙烯系樹脂、矽氧系樹脂等為基質聚合物，於其中添加如異氰酸酯化合物、環氧化合物、如氮丙啶(aziridine)的交聯劑之黏著劑組成物而成。再者，亦可為含有微粒子而顯示光散射性的黏著劑層。黏著劑層的厚度，通常為1~40μm，較佳為3~25μm。 When the adhesive layer of one example of the peripheral member is attached to the polarizing plate 2 having the protective film on both sides, it can be laminated on the outer surface of any of the protective films, and when the polarizing plate 1 having the protective film is provided on one side, for example, it can be laminated on the polarizing plate. The face of the sheet opposite the protective film. The adhesive for forming the adhesive layer is usually a matrix polymer composed of a (meth)acrylic resin, a styrene resin, a siloxane resin, or the like, to which an isocyanate compound, an epoxy compound, such as aziridine is added. Aziridine) is an adhesive composition of a crosslinking agent. Further, it may be an adhesive layer which exhibits light scattering properties by containing fine particles. The thickness of the adhesive layer is usually from 1 to 40 μm, preferably from 3 to 25 μm.
而且，作為周邊構件的其他例之光學功能性膜，例如透過某種偏光的光，反射顯示與其相反性質的偏光的光之反射型偏光膜；表面具有凹凸形狀之附有抗眩功能的膜；附有表面抗反射功能的膜；表面具有反射功能的反射膜；兼具反射功能及透過功能之半透過反射膜；視角補償膜等。 Further, as an optical functional film of another example of the peripheral member, for example, a light-reflecting polarizing film that transmits polarized light of a reverse polarity is transmitted through light of a certain polarized light, and a film having an anti-glare function having a concave-convex shape on the surface; A film with a surface anti-reflection function; a reflective film with a reflective function on the surface; a semi-transmissive reflective film with both a reflective function and a transmissive function; and a viewing angle compensation film.
以下，顯示實施例及比較例，更具體地說明本發明，但本發明不限於該等例。 Hereinafter, the present invention will be more specifically described by showing examples and comparative examples, but the present invention is not limited to the examples.
〈實施例1〉 <Example 1>
(1)底塗層形成步驟 (1) Undercoat layer forming step
聚乙烯醇粉末(日本合成化學工業(股)製「Z-200」、平均聚合度1100、平均皂化度99.5莫耳%)溶解於95℃的熱水，調製濃度3重量%的聚乙烯醇水溶液。於所得之水溶液中相對於聚乙烯醇粉末6重量份混合5重量份的比例之交聯劑(田岡化學工業(股)製「SUMIREZ RESIN 650」)，得到底塗層形成用塗佈液。 Polyvinyl alcohol powder ("Z-200" manufactured by Nippon Synthetic Chemical Industry Co., Ltd., average polymerization degree 1100, average saponification degree: 99.5 mol%) was dissolved in hot water at 95 ° C to prepare a 3 wt% aqueous solution of polyvinyl alcohol. . In the obtained aqueous solution, a crosslinking agent ("SUMIREZ RESIN 650" manufactured by Tajika Chemical Industry Co., Ltd.) was added in an amount of 5 parts by weight based on 6 parts by weight of the polyvinyl alcohol powder to obtain a coating liquid for forming an undercoat layer.
然後，準備厚度110μm的未延伸聚丙烯(PP)膜(熔點：163℃)作為基材膜，於其單面實施電暈處理後，於該電暈處理面使用微凹版塗佈機，塗佈上述底塗層形成用塗佈液，藉由80℃、10分鐘的乾燥，形成厚度0.2μm之底塗層。 Then, an unstretched polypropylene (PP) film (melting point: 163 ° C) having a thickness of 110 μm was prepared as a base film, and after performing corona treatment on one side thereof, a micro gravure coater was applied to the corona-treated surface. The coating liquid for forming an undercoat layer was dried at 80 ° C for 10 minutes to form an undercoat layer having a thickness of 0.2 μm.
(2)積層膜的製作(樹脂層形成步驟) (2) Production of laminated film (resin layer forming step)
將聚乙烯醇粉末(Kuraray(股)製「PVA124」、平均聚合度2400、平均皂化度98.0~99.0莫耳%)溶解於95℃的熱水中，調製濃度8重量%的聚乙烯醇水溶液，將其作為聚乙烯醇系樹脂層形成用塗佈液。 Polyvinyl alcohol powder ("PVA124" manufactured by Kuraray Co., Ltd., average polymerization degree 2400, average saponification degree: 98.0 to 99.0 mol%) was dissolved in hot water at 95 ° C to prepare a polyvinyl alcohol aqueous solution having a concentration of 8 wt%. This is used as a coating liquid for forming a polyvinyl alcohol-based resin layer.
於上述(1)製作的具有底塗層的基材膜的底塗層表面，使用唇式塗佈機，塗佈上述聚乙烯醇系樹脂層形成用塗佈液後，藉由80℃、20分鐘的乾燥，於底塗層上形成聚乙烯醇系樹脂層，得到包含基材膜/底塗層/聚乙烯醇系樹脂層的積層膜。 The surface of the undercoat layer of the base film having an undercoat layer produced in the above (1) was applied to the coating liquid for forming a polyvinyl alcohol-based resin layer using a lip coater, and then 80 ° C, 20 After drying for a minute, a polyvinyl alcohol-based resin layer was formed on the undercoat layer to obtain a laminated film including a base film/undercoat layer/polyvinyl alcohol-based resin layer.
(3)延伸膜的製作(延伸步驟) (3) Production of stretch film (extension step)
對上述(2)製作的積層膜，使用拉幅裝置，於160℃下，實施5.3倍的自由端一軸延伸，得到延伸膜。延伸後的聚 乙烯醇系樹脂層的厚度為5.0μm。 The laminated film produced in the above (2) was stretched by a 5.3-fold free end at 160 ° C using a tenter to obtain a stretched film. Extended poly The thickness of the vinyl alcohol-based resin layer was 5.0 μm.
(4)偏光性積層膜的製作(染色步驟) (4) Production of polarizing laminated film (dyeing step)
將上述(3)製作的延伸膜浸漬於含有碘與碘化鉀之26℃的染色水溶液(水每100重量份，含有碘0.35重量份、碘化鉀10重量份)，進行染色處理後，浸漬於含有硼酸及碘化鉀之78℃的交聯水溶液(水每100重量份，含有硼酸9.5重量份及碘化鉀5重量份)300秒，進行交聯處理。然後，以8℃的純水洗淨10秒，最後，藉由於40~50℃、200秒進行乾燥，得到包含基材膜/底塗層/偏光片層的偏光性積層膜。 The stretched film prepared in the above (3) is immersed in a dyeing aqueous solution containing 26% by weight of iodine and potassium iodide (containing 0.35 parts by weight of iodine and 10 parts by weight of potassium iodide per 100 parts by weight of water), followed by dyeing treatment, and then immersed in boric acid and A crosslinked aqueous solution of 78 ° C of potassium iodide (9.5 parts by weight of boric acid and 5 parts by weight of potassium iodide per 100 parts by weight of water) was subjected to a crosslinking treatment for 300 seconds. Then, it was washed with pure water at 8 ° C for 10 seconds, and finally, dried at 40 to 50 ° C for 200 seconds to obtain a polarizing laminated film including a base film/undercoat layer/polarizing sheet layer.
(5)偏光板的製作(保護膜貼合步驟及剝離步驟) (5) Production of polarizing plate (protective film bonding step and peeling step)
將聚乙烯醇粉末((股)Kuraray製的「KL-318」、平均聚合度1800)溶解於95℃的熱水中，調製濃度3重量%的聚乙烯醇水溶液，於所得的水溶液中相對於聚乙烯醇粉末2重量份混合1重量份的比例之交聯劑(田岡化學工業(股)製的商品名「SUMIREZ RESIN 650」)，得到接著劑水溶液。 Polyvinyl alcohol powder ("KL-318" manufactured by Kuraray Co., Ltd., average polymerization degree 1800) was dissolved in hot water at 95 ° C to prepare a polyvinyl alcohol aqueous solution having a concentration of 3 % by weight, and the obtained aqueous solution was compared with the obtained aqueous solution. 2 parts by weight of a polyvinyl alcohol powder, a cross-linking agent (trade name "SUMIREZ RESIN 650", manufactured by Tajika Chemical Industry Co., Ltd.) was mixed in an amount of 1 part by weight to obtain an aqueous solution of an adhesive.
然後，於上述(4)製作的偏光性積層膜的偏光片層的外面(貼合面)，塗佈上述接著劑水溶液後，貼合25℃ 85%RH環境下放置24小時而調整水分率的包含保護膜[三乙醯基纖維素(TAC)]的透明保護膜(柯尼卡美能達光學(股)製的「KC4UY」、厚度40μm)，藉由通過一對貼合滾輪間而壓合後，使接著劑層乾燥，得到包含基材膜/底塗層/偏光片層/接著劑層/保護膜的附有保護膜的偏光性積層 膜。再者，如下述比較例1所示，上述保護膜在25℃ 55%RH下的平衡水分率為1.08%。上述保護膜的飽和水分率為3.53%。 Then, the above-mentioned aqueous solution of the adhesive is applied to the outer surface (bonding surface) of the polarizer layer of the polarizing laminate film produced in the above (4), and then placed in an environment of 25° C. and 85% RH for 24 hours to adjust the water content. A transparent protective film ("KC4UY" manufactured by Konica Minolta Optical Co., Ltd., thickness 40 μm) containing a protective film [triacetyl cellulose (TAC)], which is pressed by a pair of bonding rollers Thereafter, the adhesive layer is dried to obtain a polarizing laminate with a protective film including a base film/undercoat/polarizer layer/adhesive layer/protective film. membrane. Further, as shown in the following Comparative Example 1, the equilibrium moisture content of the above protective film at 25 ° C and 55% RH was 1.08%. The saturated moisture content of the above protective film was 3.53%.
最後，從附有保護膜的偏光性積層膜，剝離除去基材膜。可容易地剝離基材膜，得到單面附有保護膜的偏光板。 Finally, the base film is peeled off from the polarizing laminated film with a protective film. The base film can be easily peeled off to obtain a polarizing plate with a protective film on one side.
〈實施例2〉 <Example 2>
除使保護膜的水分率在25℃ 70%RH環境下放置24小時而進行以外，係與實施例1同樣地，製作單面附有保護膜的偏光板。 A polarizing plate having a protective film on one side thereof was produced in the same manner as in Example 1 except that the moisture content of the protective film was allowed to stand in an environment of 25 ° C and 70% RH for 24 hours.
〈比較例1〉 <Comparative Example 1>
除使保護膜的水分率在25℃ 55%RH環境下放置24小時而進行以外，係與實施例1同樣地，製作單面附有保護膜的偏光板。 A polarizing plate having a protective film on one side thereof was produced in the same manner as in Example 1 except that the moisture content of the protective film was allowed to stand in an environment of 25 ° C and 55% RH for 24 hours.
〈比較例2〉 <Comparative Example 2>
除使保護膜的水分率在40℃ 55%RH環境下放置24小時而進行以外，係與實施例1同樣地，製作單面附有保護膜的偏光板。 A polarizing plate having a protective film on one side thereof was produced in the same manner as in Example 1 except that the moisture content of the protective film was allowed to stand in an environment of 40 ° C and 55% RH for 24 hours.
各實施例/比較例所使用的保護膜對偏光片層貼合時的水分率(wt/wt%)，與保護膜的調濕條件一起表示於表1。水分率係根據前述的算出式求得。 The moisture content (wt/wt%) of the protective film used in each of the examples and the comparative examples when they were bonded to the polarizer layer was shown in Table 1 together with the humidity-conditioning conditions of the protective film. The water content is obtained by the above calculation formula.
[偏光板的捲曲量的測定及其評價] [Measurement and Evaluation of Curl Amount of Polarizing Plate]
從所得之單面附有保護膜的偏光板，切出吸收軸方向(MD)80mm×穿透軸方向(TD)80mm的測試片，在25℃ 55% RH 環境下放置24小時。該測試片係具有使偏光片層側設為內側而捲曲的逆捲曲，若於基準面(水平台面)上使凹面朝上，4個端側成為高起的狀態。在該狀態，分別對測試片的4個角，測定離基準面的高度，平均該等4個角的高度，求得捲曲量，根據下述評價基準，評價捲曲的抑制程度。結果表示於表1。 From the obtained polarizing plate with a protective film on one side, a test piece having an absorption axis direction (MD) of 80 mm × a transmission axis direction (TD) of 80 mm was cut out at 25 ° C and 55% RH. Leave it in the environment for 24 hours. This test piece has a reverse curl in which the side of the polarizer layer is formed inside and curled, and when the concave surface faces upward on the reference surface (water platform surface), the four end sides are raised. In this state, the heights from the reference plane were measured for the four corners of the test piece, and the heights of the four corners were averaged to obtain the amount of curl, and the degree of suppression of the curl was evaluated based on the following evaluation criteria. The results are shown in Table 1.
A：捲曲量未達28mm，且偏光板的捲曲被充分抑制 A: The curl amount is less than 28 mm, and the curl of the polarizing plate is sufficiently suppressed
B：捲曲量為28mm以上，且偏光板的捲曲顯著 B: The amount of curl is 28 mm or more, and the curl of the polarizing plate is remarkable
上述評價基準係根據以下的理由。上述捲曲量未達28mm時，單面附有保護膜的偏光板之保護膜外面，貼合防止刮傷用的保護膜(附有黏著劑層的聚對苯二甲酸二乙酯膜)時，可得到幾乎平坦的複合偏光板。再者，於該複合偏光板的偏光片層外面，即使貼合液晶胞貼合用的黏著劑層，複合偏光板亦可保持幾乎平坦的狀態。 The above evaluation criteria are based on the following reasons. When the amount of crimping is less than 28 mm, the outer surface of the protective film of the polarizing plate having the protective film on one side thereof is bonded to the protective film for preventing scratching (the polyethylene terephthalate film with the adhesive layer). A nearly flat composite polarizer is obtained. Further, on the outer surface of the polarizer layer of the composite polarizing plate, even if the adhesive layer for liquid crystal cell bonding is bonded, the composite polarizing plate can be maintained in a nearly flat state.
相反地，上述捲曲量為28mm以上時，即使貼合保護膜於保護膜外面，所得之複合偏光板於逆捲曲方向捲曲。再者，於該複合偏光板的偏光片層的外面，即使貼合液晶胞貼合用的黏著劑層，亦維持逆捲曲的狀態。而且，於23℃ 55% RH環境下放置數日後，再次觀察時，產生逆捲曲變得更大的缺陷。 On the other hand, when the amount of curling is 28 mm or more, even if the protective film is bonded to the outside of the protective film, the obtained composite polarizing plate is curled in the reverse crimping direction. Further, on the outer surface of the polarizer layer of the composite polarizing plate, even if the adhesive layer for liquid crystal cell bonding is bonded, the state of the reverse curl is maintained. Further, after standing for several days in an environment of 23 ° C and 55% RH, when observed again, a defect in which the reverse curl became larger occurred.
S10‧‧‧第1保護膜貼合步驟 S10‧‧‧1st protective film bonding step
S20‧‧‧剝離步驟 S20‧‧‧ peeling step
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