TW201544295A

TW201544295A - Polyester film, method of manufacturing the polyester film, polarizing plate, image device, hard coat film and touch panel

Info

Publication number: TW201544295A
Application number: TW104116640A
Authority: TW
Inventors: Maki Mifune
Original assignee: Fujifilm Corp
Priority date: 2014-05-26
Filing date: 2015-05-25
Publication date: 2015-12-01
Also published as: WO2015182494A1; CN106461842A; CN106461842B; JP2015225129A

Abstract

The present invention relates to a polyester film that is suitable to serve as a liquid crystal film base material or a component for a touch panel, a method of manufacturing the polyester film, a polarizing plate, an image display device, a hard coat film and a touch panel. More specifically, the present invention relates to a polyester film that helps eliminate film breaking in a polarizing plate processing step or a coating step, is particularly suitable for use in an optical film, and is particularly suitable for use as a base material of a liquid crystal display, is preferably mono-axially aligned, and a manufacturing method thereof, and a polarizing plate, an image display device, a hard coat film, and a touch panel using the polyester film.

Description

聚酯膜、聚酯膜的製造方法、偏振板、圖像顯示裝置、硬塗膜及觸摸面板Polyester film, method for producing polyester film, polarizing plate, image display device, hard coating film and touch panel

本發明涉及可作為液晶膜基材或觸摸面板用構件適宜使用的聚酯膜、聚酯膜的製造方法、偏振板、圖像顯示裝置、硬塗膜及觸摸面板。更詳細而言，涉及消除偏振板加工步驟或塗布步驟中的膜斷裂的、特別適合於光學膜用途、特別是作為液晶顯示器的基材的使用的、優選單軸配向的聚酯膜及其製造方法、使用該聚酯膜的偏振板、圖像顯示裝置、硬塗膜以及觸摸面板。The present invention relates to a polyester film which can be suitably used as a liquid crystal film substrate or a member for a touch panel, a method for producing a polyester film, a polarizing plate, an image display device, a hard coat film, and a touch panel. More specifically, it relates to a preferably uniaxially oriented polyester film which is particularly suitable for use in optical film applications, particularly as a substrate for liquid crystal displays, and which is capable of eliminating film breakage in a polarizing plate processing step or coating step. A method, a polarizing plate using the polyester film, an image display device, a hard coat film, and a touch panel.

液晶顯示器（LCD）、等離子體顯示器（PDP）、電致發光顯示器（OELD或IELD）、場致發射顯示器（FED）、觸摸面板、電子紙等圖像顯示裝置在圖像顯示面板的顯示畫面側配置有偏振板。例如，液晶顯示裝置作為耗電量小、節省空間的圖像顯示裝置其用途逐年擴大。以往，液晶顯示裝置的顯示圖像的視角依賴性大是大的缺點，但VA模式、IPS模式等廣視角液晶模式被實用化，由此，在電視機等要求高品質的圖像的市場中，液晶顯示裝置的需求也在急速擴大。Image display device such as liquid crystal display (LCD), plasma display (PDP), electroluminescent display (OELD or IELD), field emission display (FED), touch panel, electronic paper, etc. on the display screen side of the image display panel It is equipped with a polarizing plate. For example, the liquid crystal display device has been expanding its use as an image display device that consumes less power and saves space. Conventionally, the viewing angle dependence of the display image of the liquid crystal display device is large, but the wide viewing angle liquid crystal mode such as the VA mode or the IPS mode has been put into practical use, and thus, in a market where high quality images such as televisions are required. The demand for liquid crystal display devices is also rapidly expanding.

液晶顯示裝置中使用的偏振板通常成為由使碘或染料吸附配向而得到的聚乙烯醇膜等構成的偏振片和在該偏振片的表背兩側貼合有透明的保護膜（偏振板保護膜）的構成。為了方便起見，將與液晶單元貼合的面（顯示側的相反側）的保護膜稱為內膜，將相對側（顯示側）稱為外膜。聚酯、聚碳酸酯樹脂等由於具有成本也低廉、機械強度高、具有低透濕性等優點，所以被期待作為外膜的有效利用。The polarizing plate used in the liquid crystal display device is usually a polarizing plate composed of a polyvinyl alcohol film obtained by adsorbing iodine or a dye, and a transparent protective film is attached to both sides of the front and back of the polarizing plate (polarizing plate protection) The composition of the film). For the sake of convenience, the protective film on the surface to which the liquid crystal cell is bonded (the side opposite to the display side) is referred to as an inner film, and the opposite side (display side) is referred to as an outer film. Polyester, polycarbonate resin and the like are expected to be effectively utilized as an outer film because of their advantages such as low cost, high mechanical strength, and low moisture permeability.

其中，近年來，代替以往的雙軸配向聚酯膜，單軸配向聚酯膜被用作液晶顯示器的基材（偏振板的保護膜等）的情況在增加。例如，已知有作為改善了虹斑(rainbow-like unevenness)的偏振板保護膜，通過將Re=3000～30000nm、Re/Rth≥0.2的單軸配向或雙軸配向聚酯膜用於偏振板保護膜中，從而使虹斑不顯眼至無法視覺辨認的程度，消除虹斑的例子（參照專利文獻1）。另外，在專利文獻1中，還記載了就完全的單軸性（單軸對稱）膜而言與配向方向正交的方向的機械強度顯著降低。Among them, in recent years, in place of the conventional biaxial alignment polyester film, the uniaxial alignment polyester film has been used as a substrate (a protective film for a polarizing plate, etc.) of a liquid crystal display. For example, a polarizing plate protective film as a rainbow-like unevenness is known, which is used for a polarizing plate by a uniaxial alignment or biaxial alignment polyester film of Re = 3000 to 30000 nm and Re/Rth ≥ 0.2. In the protective film, an example in which the rainbow spot is inconspicuous to the extent that it is impossible to visually recognize and the rainbow spot is eliminated (refer to Patent Document 1). Further, Patent Document 1 also discloses that the mechanical strength in the direction orthogonal to the alignment direction is remarkably lowered in the case of a completely uniaxial (uniaxially symmetric) film.

具有上述那樣的光學特性的單軸配向或雙軸配向聚酯膜通過將至少未拉伸的膜使用拉幅機式拉伸裝置邊用夾子夾持邊進行單軸拉伸來製造。The uniaxially oriented or biaxially oriented polyester film having the above-described optical characteristics is produced by uniaxially stretching a film which is at least unstretched while being sandwiched by a clip using a tenter type stretching apparatus.

現有技術文獻Prior art literature

專利文獻Patent literature

專利文獻1：日本特開2012-256014號公報Patent Document 1: Japanese Laid-Open Patent Publication No. 2012-256014

發明所要解決的課題Problem to be solved by the invention

在單軸方向具有強配向的膜在用於偏振板保護膜的情況下，難以視覺辨認到虹斑，另一方面，存在與配向方向正交的方向的機械強度顯著降低，在拉伸後的搬送中發生熱收縮時容易破裂的問題。實際上，專利文獻1等中記載的主要進行了橫向拉伸的單軸配向聚酯膜由於膜僅在橫向上進行配向，所以縱向的斷裂強度弱，經常在搬送中膜產生裂紋或者斷裂。In the case where the film having a strong alignment in the uniaxial direction is used for the polarizing plate protective film, it is difficult to visually recognize the rainbow spot, and on the other hand, the mechanical strength in the direction orthogonal to the alignment direction is remarkably lowered, after stretching A problem that is easily broken when heat shrinkage occurs during transportation. In the uniaxial alignment polyester film which is mainly subjected to the transverse stretching as described in Patent Document 1 and the like, since the film is aligned only in the lateral direction, the fracture strength in the longitudinal direction is weak, and the film is often cracked or broken during transportation.

進而，本發明人進行了研究，結果發現在單軸方向具有強配向的膜的平面性差，容易帶有傷痕。在將聚酯膜用於光學用途的情況下，傷痕少不易成為圖像故障的原因，故優選。Further, the inventors of the present invention conducted research and found that a film having a strong alignment in the uniaxial direction is inferior in planarity and is likely to be scratched. When the polyester film is used for optical applications, it is preferable that the scar is less likely to cause image failure.

本發明所要解決的課題是提供傷痕少、搬送時的裂紋、斷裂少、在組裝到液晶顯示裝置中時能夠抑制虹斑的產生的聚酯膜及聚酯膜的製造方法。An object of the present invention is to provide a polyester film and a method for producing a polyester film which are capable of suppressing generation of rainbow spots when incorporated in a liquid crystal display device, with less scratches, cracks during transportation, and less breakage.

用於解決課題的方案Solution for solving problems

為了解決上述課題，本發明人進行了深入研究，結果發現，通過製成厚度薄、由於Re/Rth比大所以降低了與配向方向正交的方向的熱收縮率、及平面性良好的膜，可得到傷痕少、搬送時的裂紋、斷裂少、在組裝到液晶顯示裝置中時能夠抑制虹斑的產生的實用性高的聚酯膜。In order to solve the problem, the present inventors have conducted intensive studies and found that a film having a small thickness and a large Re/Rth ratio reduces the heat shrinkage ratio in the direction orthogonal to the alignment direction and the planarity. A polyester film having a high degree of scratches, a crack at the time of conveyance, and a small amount of breakage, and capable of suppressing generation of rainbow spots when incorporated in a liquid crystal display device can be obtained.

作為用於達成上述課題的具體方案的本發明如下所述。The present invention as a specific solution for achieving the above problems is as follows.

[1]一種聚酯膜，其是厚度為10～150μm，面內方向的延遲Re及厚度方向的延遲Rth為3000～30000nm，Re/Rth超過0.8且為2.5以下，與配向方向正交的方向的熱收縮率為0.6%以下的聚酯膜，將卷曲成卷狀的聚酯膜的最外表層開卷並切出500mm見方的聚酯膜放置在平面上時的聚酯膜的浮起為1.8mm以下。[1] A polyester film having a thickness of 10 to 150 μm, a retardation Re in the in-plane direction, and a retardation Rth in the thickness direction of 3,000 to 30,000 nm, and a Re/Rth exceeding 0.8 and 2.5 or less, and a direction orthogonal to the alignment direction. The polyester film having a heat shrinkage ratio of 0.6% or less is obtained by unwinding the outermost surface layer of the polyester film curled into a roll and cutting the polyester film of 500 mm square when placed on a flat surface. Below mm.

[2]根據[1]所述的聚酯膜，其中，下述式A所表示的與配向方向正交的方向的熱收縮率不均(heat shrinkage unevenness)優選為0.4%以下。式A：（與配向方向正交的方向的熱收縮率不均）=（配向方向的3點處的在150℃下加熱30分鐘後的與配向方向正交的方向的熱收縮率的最大值與最小值之差）/（配向方向的3點處的在150℃下加熱30分鐘後的與配向方向正交的方向的熱收縮率的平均值）×100%[2] The polyester film according to the above [1], wherein the heat shrinkage unevenness in the direction orthogonal to the alignment direction represented by the following formula A is preferably 0.4% or less. Formula A: (The heat shrinkage rate unevenness in the direction orthogonal to the alignment direction) = (Maximum value of the heat shrinkage rate in the direction orthogonal to the alignment direction after heating at 150 ° C for 30 minutes at three points in the alignment direction) (the difference from the minimum value) / (the average value of the heat shrinkage rate in the direction orthogonal to the alignment direction after heating at 150 ° C for 3 minutes at 3 points in the alignment direction) × 100%

[3]一種聚酯膜的製造方法，其包括以下步驟：使用具有多個邊夾持膜邊在一對軌道間移動的夾子的拉伸機，在各軌道上同時進行由縮短上述的夾子間的距離引起的向膜搬送方向的收縮、和由擴大所述的夾子移動的一對軌道間的距離引起的向與膜搬送方向正交的方向的拉伸的步驟，[3] A method for producing a polyester film, comprising the steps of: simultaneously shortening the above-described clips by using a stretching machine having a plurality of clips that sandwich a film while moving between a pair of rails a step of contracting in the film transport direction by the distance and stretching in a direction orthogonal to the film transport direction by a distance between the pair of rails that expand the clip,

所述的向膜搬送方向的收縮率和向與膜搬送方向正交的方向的拉伸倍率在拉伸中總是滿足下述式B1的關係，並且滿足下述式B2及式B3； [數學式1]･･･式B1 [數學式2]･･･式B2 [數學式3]･･･式B3The shrinkage ratio in the film transport direction and the draw ratio in the direction orthogonal to the film transport direction always satisfy the relationship of the following formula B1 during stretching, and satisfy the following formulas B2 and B3; Formula 1] ・・・式B1 [Math 2] ・・・式B2 [Math 3] ・・・式B3

式B1、B2及B3中，In Equations B1, B2, and B3,

x表示拉伸機的入口的寬度，單位為mm；x represents the width of the inlet of the stretching machine, in mm;

x’表示拉伸中的各位置處的聚酯膜的寬度，單位為mm；x' represents the width of the polyester film at each position in the stretching, in units of mm;

x_max 表示拉伸中的聚酯膜的最大寬度，單位為mm；x _max represents the maximum width of the polyester film in stretching, in units of mm;

y表示拉伸機的入口處的各軌道上的夾子間的距離，單位為mm；y represents the distance between the clips on each track at the entrance of the stretching machine, in mm;

y’表示拉伸中的各位置處的各軌道上的夾子間的距離，單位為mm；y' represents the distance between the clips on each track at each position in the stretching, in mm;

y_min 表示拉伸中的各軌道上的夾子間的距離的最小值，單位為mm。y _min represents the minimum value of the distance between the clips on each track in the stretch, in mm.

[4]一種聚酯膜的製造方法，其是包括以下步驟：使用具有多個邊夾持膜邊在一對軌道間移動的夾子的拉伸機，在各軌道上同時進行由縮短所述的夾子間的距離引起的向膜搬送方向的收縮、和由擴大所述的夾子移動的一對軌道間的距離引起的向與膜搬送方向正交的方向的拉伸的步驟，[4] A method for producing a polyester film, comprising the steps of: simultaneously shortening the stretching on each of the rails by using a stretching machine having a plurality of clips that sandwich the film while moving between the pair of rails a step of contracting in the film transport direction by the distance between the clips and stretching in a direction orthogonal to the film transport direction by a distance between the pair of rails that expand the clip,

所述的向膜搬送方向的收縮率和向與膜搬送方向正交的方向的拉伸倍率在拉伸中總是滿足下述式B1的關係、並且滿足下述式B2及式B3聚酯膜的製造方法，The shrinkage ratio in the film transport direction and the draw ratio in the direction orthogonal to the film transport direction always satisfy the relationship of the following formula B1 during stretching, and satisfy the following formula B2 and formula B3. Manufacturing method,

所述的聚酯膜的厚度為10～150μm，The polyester film has a thickness of 10 to 150 μm.

所述的聚酯膜的與配向方向正交的方向的熱收縮率為0.6%以下； [數學式4]･･･式B1 [數學式5]･･･式B2 [數學式6]･･･式B3The heat shrinkage ratio of the polyester film in a direction orthogonal to the alignment direction is 0.6% or less; [Math 4] ・・・式B1 [Math 5] ・・・式B2 [Math 6] ・・・式B3

式B1、B2及B3中，In Equations B1, B2, and B3,

[5]根據[3]或[4]所述的聚酯膜的製造方法，其優選在同時在拉伸平均溫度T1下進行向膜搬送方向的收縮和所述的向與膜搬送方向正交的方向的拉伸後，包括在熱定型溫度T2≥T1+30℃下進行加熱的熱定型步驟；[5] The method for producing a polyester film according to [3] or [4], wherein it is preferable to perform shrinkage in a film transport direction at the simultaneous stretching average temperature T1 and to be orthogonal to the film transport direction. After the stretching in the direction, comprising a heat setting step of heating at a heat setting temperature T2 ≥ T1 + 30 ° C;

其中，T1及T2的單位為℃。Among them, the unit of T1 and T2 is °C.

[6]根據[5]所述的聚酯膜的製造方法，其中，優選邊進行向膜搬送方向的收縮邊進行熱定型。[6] The method for producing a polyester film according to [5], wherein it is preferable to perform heat setting while performing shrinkage in a film transport direction.

[7]根據[5]或[6]所述的聚酯膜的製造方法，其中，優選熱定型溫度T2超過T1+50℃。[7] The method for producing a polyester film according to [6], wherein the heat setting temperature T2 is more than T1 + 50 °C.

[8]一種偏振板，其包含偏振片、和[1]或[2]所述的聚酯膜。[8] A polarizing plate comprising a polarizing plate, and the polyester film according to [1] or [2].

[9]一種圖像顯示裝置，其具備[1]或[2]所述的聚酯膜、或[8]所述的偏振板。[9] An image display device comprising the polyester film according to [1] or [2], or the polarizing plate according to [8].

[10]一種硬塗膜，其包含[1]或[2]所述的聚酯膜。[10] A hard coat film comprising the polyester film according to [1] or [2].

[11]一種觸摸面板，其具備[1]或[2]所述的聚酯膜、[8]所述的偏振板、或[10]所述的硬塗膜。[11] A touch panel comprising the polyester film according to [1] or [2], the polarizing plate according to [8], or the hard coat film according to [10].

發明效果Effect of the invention

根據本發明，能夠提供傷痕少、搬送時的裂紋、斷裂少、在組裝到液晶顯示裝置中時能夠抑制虹斑的產生的聚酯膜。According to the present invention, it is possible to provide a polyester film which has few scratches, cracks during transportation, and little breakage, and can suppress generation of rainbow spots when incorporated in a liquid crystal display device.

根據本發明，能夠提供該聚酯膜的製造方法。根據本發明，能夠提供使用該聚酯膜的偏振板、圖像顯示裝置、硬塗膜及觸摸面板。According to the invention, a method of producing the polyester film can be provided. According to the invention, it is possible to provide a polarizing plate, an image display device, a hard coat film, and a touch panel using the polyester film.

以下，對本發明的聚酯膜及其製造方法、偏振板、圖像顯示裝置、硬塗膜及觸摸面板進行詳細說明。Hereinafter, the polyester film of the present invention, a method for producing the same, a polarizing plate, an image display device, a hard coat film, and a touch panel will be described in detail.

以下記載的構成要件的說明有時基於本發明的代表性實施方式進行，但本發明並不限定於那樣的實施方式。另外，在本說明書中，使用“～”表示的數值範圍是指包含“～”的前後記載的數值作為下限值及上限值的範圍。The description of the constituent elements described below may be performed based on representative embodiments of the present invention, but the present invention is not limited to such an embodiment. In the present specification, the numerical range represented by "to" means a range including the numerical values described before and after "~" as the lower limit and the upper limit.

此外，在後面進行詳細敘述，聚酯膜通常通過使用輥等進行搬送、拉伸來得到。此時，將膜搬送方向也稱為MD（Machine Direction，縱向）方向。此外，膜的搬送方向也稱為膜的長度方向。膜搬送方向也稱為縱向，將膜的向搬送方向的拉伸稱為縱向拉伸，將向膜搬送方向的收縮也稱為縱向收縮。Further, as will be described later in detail, the polyester film is usually obtained by conveying and stretching using a roll or the like. At this time, the film transport direction is also referred to as an MD (Machine Direction) direction. Further, the transport direction of the film is also referred to as the longitudinal direction of the film. The film transport direction is also referred to as a longitudinal direction, and the stretching of the film in the transport direction is referred to as longitudinal stretching, and the contraction in the film transport direction is also referred to as longitudinal contraction.

此外，膜寬度方向是與長度方向正交的方向。膜寬度方向在邊搬送膜邊進行製造的膜中，也稱為與膜搬送方向正交的方向、即TD（Transverse Direction，橫向）方向。與膜搬送方向正交的方向也稱為橫向，將膜的向與搬送方向正交的方向的拉伸也稱為橫向拉伸。Further, the film width direction is a direction orthogonal to the longitudinal direction. The film produced in the film width direction while being transported while transporting the film is also referred to as a direction orthogonal to the film transport direction, that is, a TD (Transverse Direction) direction. The direction orthogonal to the film transport direction is also referred to as the lateral direction, and the stretching of the film in the direction orthogonal to the transport direction is also referred to as lateral stretching.

[聚酯膜][Polyester film]

本發明的聚酯膜是厚度為10～150μm，面內方向的延遲Re及厚度方向的延遲Rth為3000～30000nm，Re/Rth超過0.8且為2.5以下，與配向方向正交的方向的熱收縮率為0.6%以下的聚酯膜，將卷曲成卷狀的聚酯膜的最外表層開卷並切出500mm見方的聚酯膜放置在平面上時的聚酯膜的浮起為1.8mm以下。The polyester film of the present invention has a thickness of 10 to 150 μm, a retardation Re in the in-plane direction, and a retardation Rth in the thickness direction of 3,000 to 30,000 nm, a Re/Rth of more than 0.8 and 2.5 or less, and a heat shrinkage in a direction orthogonal to the alignment direction. In the polyester film having a rate of 0.6% or less, the outermost surface layer of the polyester film which is wound into a roll is unwound, and the polyester film which is cut into a 500 mm square is placed on a flat surface to have a float of 1.8 mm or less.

通過這樣的構成，本發明的聚酯膜的傷痕少，搬送時的裂紋、斷裂少，在組裝到液晶顯示裝置中時能夠抑制虹斑的產生。With such a configuration, the polyester film of the present invention has less scratches and has less cracks and breakage during transportation, and can suppress generation of rainbow spots when incorporated in a liquid crystal display device.

以下，對本發明的聚酯膜的優選的方式進行說明。Hereinafter, a preferred embodiment of the polyester film of the present invention will be described.

＜聚酯膜的特性＞<Characteristics of Polyester Film>

（膜厚）(film thickness)

本發明的聚酯膜的厚度為10～150μm，優選為20～150μm，更優選為30～130μm，進一步優選為35～110μm以下。在10μm以下時，機械強度低且在搬送中容易破裂而實用性低。在150μm以上時，偏振板的厚度變厚，作為要求薄度的液晶電視機或觸摸面板用途不優選。The polyester film of the present invention has a thickness of 10 to 150 μm, preferably 20 to 150 μm, more preferably 30 to 130 μm, still more preferably 35 to 110 μm or less. When it is 10 μm or less, the mechanical strength is low, and it is easily broken during transportation, and the utility is low. When the thickness is 150 μm or more, the thickness of the polarizing plate is increased, which is not preferable as a liquid crystal television or a touch panel which is required to be thin.

（相位差）(phase difference)

通過膜面內的延遲Re及厚度方向的延遲Rth為3000～30000nm，Re/Rth比率超過0.8且為2.5以下，在作為偏振板保護膜使用時的從傾斜方向觀察時，見不到虹斑，能夠保持良好的視覺辨認性。The retardation Re in the film plane and the retardation Rth in the thickness direction are 3,000 to 30,000 nm, and the Re/Rth ratio is more than 0.8 and 2.5 or less. When viewed as a polarizing plate protective film, the rainbow spot is not observed when viewed from the oblique direction. Can maintain good visibility.

本發明的聚酯膜的面內方向的延遲Re為3000～30000nm，優選為3500～25000nm，進一步優選為4000～20000nm以下。若Re超過3000nm，則在製成面板時，畫面中難以產生虹斑，優選。製作超過30000nm的膜原理上較難。即使聚酯膜的Re超過30000nm，也只是虹斑降低效果飽和，得到本發明的效果。The retardation Re in the in-plane direction of the polyester film of the present invention is from 3,000 to 30,000 nm, preferably from 3,500 to 25,000 nm, and more preferably from 4,000 to 20,000 nm. When Re exceeds 3000 nm, it is preferable that rainbow spots are hard to occur in a screen when a panel is produced. It is difficult to make a film of more than 30,000 nm in principle. Even if the Re of the polyester film exceeds 30,000 nm, only the rainbow spot reduction effect is saturated, and the effect of the present invention is obtained.

虹斑是在從視覺辨認側觀察由背光源沿傾斜方向入射至具有大的雙折射、具體而言Re為500nm以上且低於3000nm的聚合物膜作為保護膜的偏振板中的光時出現的，特別是在將包含亮線光譜的、例如冷陰極管那樣的光源作為背光源的液晶顯示裝置中是顯著的。The rainbow spot appears when the light in the polarizing plate having a large birefringence, specifically, a polymer film having a Re of 500 nm or more and less than 3000 nm as a protective film, is observed from the visual recognition side by the backlight. In particular, it is remarkable in a liquid crystal display device which uses a light source such as a cold cathode tube including a bright line spectrum as a backlight.

其中，將具有連續發光光譜的白色光源作為背光源使用的情況下，本發明的聚酯膜的Re為上述範圍由於難以視覺辨認到虹斑，所以優選。In the case where a white light source having a continuous light emission spectrum is used as a backlight, the Re of the polyester film of the present invention is preferably in the above range because it is difficult to visually recognize a rainbow spot.

本發明的聚酯膜的厚度方向延遲Rth為3000～30000nm以下，優選為3500～25000nm，進一步優選為4000～20000nm以下。製作Rth低於3000nm的膜原理上較難。若為30000nm以下，則在製成面板時畫面中難以產生虹斑，優選。The polyester film of the present invention has a retardation Rth in the thickness direction of 3,000 to 30,000 nm or less, preferably 3,500 to 25,000 nm, and more preferably 4,000 to 20,000 nm or less. It is difficult to fabricate a film having an Rth of less than 3000 nm. When it is 30000 nm or less, it is difficult to generate a rainbow spot on a screen at the time of a panel formation, and it is preferable.

本發明的聚酯膜的面內方向的延遲Re與厚度方向延遲Rth的比（Re/Rth）超過0.8且為2.5以下，優選超過0.8且為2.2以下，特別優選超過0.8且為2.0以下，更特別優選0.9～2.0。若Re/Rth超過0.8，則在將本發明的聚酯膜作為偏振板保護膜組裝到液晶面板中時畫面中難以產生虹斑，優選。製作超過2.5的膜原理上較難。此外，即使Re/Rth超過2.5，虹斑的視角依賴性降低的效果也只是飽和。The ratio (Re/Rth) of the retardation Re in the in-plane direction of the polyester film of the present invention to the thickness direction retardation Rth is more than 0.8 and not more than 2.5, preferably more than 0.8 and not more than 2.2, particularly preferably more than 0.8 and not more than 2.0, more preferably It is particularly preferably 0.9 to 2.0. When Re/Rth exceeds 0.8, it is preferable that the rainbow film of the present invention is less likely to generate rainbow spots on the screen when the polyester film is incorporated as a polarizing plate protective film in a liquid crystal panel. It is difficult to make a film of more than 2.5. Further, even if the Re/Rth exceeds 2.5, the effect of reducing the viewing angle dependency of the rainbow spot is only saturated.

虹斑也可以通過使表示Re、Rth的關係的Nz值為適當的值而降低，從虹斑的降低效果及製造適應性出發，Nz值優選絕對值為2.0以下，更優選為0.5～2.0，進一步優選為0.5～1.5。The rainbow spot may be lowered by setting the Nz value indicating the relationship between Re and Rth to an appropriate value, and the Nz value preferably has an absolute value of 2.0 or less, more preferably 0.5 to 2.0, from the effect of reducing the rainbow spot and the manufacturing suitability. More preferably, it is 0.5 to 1.5.

由於虹斑由入射光產生，所以通常在白色顯示時被觀察到。Since the rainbow spot is generated by incident light, it is usually observed when displayed in white.

本發明的聚酯膜的面內相位差值Re由下述式（4）表示。The in-plane retardation value Re of the polyester film of the present invention is represented by the following formula (4).

Re=（nx-ny）×y₁ ･･･（4）Re=(nx-ny)×y ₁・・・(4)

其中，nx為聚酯膜的面內慢軸方向的折射率，ny為聚酯膜的面內快軸方向（與面內慢軸方向正交的方向）的折射率，y₁ 為聚酯膜的厚度。Wherein nx is the refractive index of the in-plane slow axis direction of the polyester film, and ny is the refractive index of the in-plane fast axis direction of the polyester film (direction orthogonal to the in-plane slow axis direction), and y ₁ is a polyester film thickness of.

本發明的聚酯膜的厚度方向的延遲Rth由下述式（5）表示。The retardation Rth in the thickness direction of the polyester film of the present invention is represented by the following formula (5).

Rth={（nx+ny）/2-nz}×y₁ ･･･（5）Rth={(nx+ny)/2-nz}×y ₁・・・(5)

其中，nz為聚酯膜的厚度方向的折射率。Here, nz is a refractive index in the thickness direction of the polyester film.

另外，聚酯膜的Nz值由下述式（6）表示。Further, the Nz value of the polyester film is represented by the following formula (6).

Nz=（nx-nz）/（nx-ny）･･･（6）Nz=(nx-nz)/(nx-ny) ・・・(6)

在本說明書中，波長λnm下的Re、Rth及Nz可以如下那樣進行測定。In the present specification, Re, Rth, and Nz at a wavelength of λ nm can be measured as follows.

使用兩片偏振板，求出聚酯膜的配向軸方向，按照配向軸方向正交的方式切出4cm×2cm的長方形，作為測定用樣品。對於該樣品，通過阿貝折射率計（ATAGO CO.,LTD.制、NAR-4T、測定波長589nm）求出正交的雙軸的折射率（Nx，Ny）、及厚度方向的折射率（Nz），將上述的雙軸的折射率差的絕對值（|Nx-Ny|）作為折射率的各向異性（△Nxy）。聚酯膜的厚度y₁ （nm）使用電動測微儀（Fine Liu full Co., Ltd.制、Miritoron 1245D）測定，將單位換算成nm。由所測定的Nx、Ny、Nz、y₁ 的值分別算出Re、Rth、Nz。Using two polarizing plates, the direction of the alignment axis of the polyester film was determined, and a rectangle of 4 cm × 2 cm was cut out so as to be orthogonal to the direction of the alignment axis, and used as a sample for measurement. With respect to this sample, the orthogonal biaxial refractive index (Nx, Ny) and the refractive index in the thickness direction were obtained by an Abbe refractometer (manufactured by ATAGO CO., LTD., NAR-4T, measurement wavelength: 589 nm). Nz), the absolute value (|Nx-Ny|) of the above-described biaxial refractive index difference is taken as the anisotropy (ΔNxy) of the refractive index. The thickness y ₁ (nm) of the polyester film was measured using an electric micrometer (manufactured by Fine Liu Full Co., Ltd., Miritoron 1245D), and the unit was converted into nm. Nx determined by the value Ny, Nz, y ₁ are calculated Re, Rth, Nz.

上述的Re、Rth可以通過膜中使用的聚酯樹脂的種類、上述的聚酯樹脂和添加劑的量、延遲顯現劑的添加、膜的膜厚、膜的拉伸方向和拉伸率等進行調整。The above Re and Rth can be adjusted by the kind of the polyester resin used in the film, the amount of the above polyester resin and the additive, the addition of the retardation developing agent, the film thickness of the film, the stretching direction of the film, and the stretching ratio. .

將本發明的聚酯膜控制在上述的Re、Rth的範圍的方法沒有特別限制，但可以通過例如拉伸法來達成。The method of controlling the polyester film of the present invention in the range of Re and Rth described above is not particularly limited, but can be achieved, for example, by a stretching method.

（與配向方向正交的方向的MD熱收縮率）(MD thermal shrinkage rate in the direction orthogonal to the alignment direction)

本發明的聚酯膜的與配向方向正交的方向的熱收縮率為0.6%以下。通過與配向方向正交的方向的熱收縮率為0.6%以下，由搬送時引起的熱收縮產生的搬送時的裂紋、斷裂變少，優選能夠抑制由偏振板加工時引起的熱收縮產生的TD方向的破裂。本發明的聚酯膜的與配向方向正交的方向的熱收縮率優選為在150℃下加熱30分鐘後的與配向方向正交的方向的熱收縮率。The heat shrinkage rate of the polyester film of the present invention in the direction orthogonal to the direction of the alignment is 0.6% or less. When the heat shrinkage rate in the direction orthogonal to the direction of the alignment is 0.6% or less, cracks and cracks during transportation due to heat shrinkage during transportation are reduced, and it is preferable to suppress TD caused by heat shrinkage caused by processing of the polarizing plate. The direction of the rupture. The heat shrinkage ratio of the polyester film of the present invention in the direction orthogonal to the alignment direction is preferably a heat shrinkage ratio in a direction orthogonal to the alignment direction after heating at 150 ° C for 30 minutes.

在本發明中，所謂在150℃下加熱30分鐘後的膜長度方向的熱收縮率（150℃、30分鐘）如下那樣進行定義。In the present invention, the heat shrinkage ratio (150 ° C, 30 minutes) in the longitudinal direction of the film after heating at 150 ° C for 30 minutes is defined as follows.

在裁切成TD方向30mm、MD方向120mm的聚酯膜的試樣片M上，預先按照在MD方向達到100mm的間隔的方式畫2根基準線。將試樣片M在無張力下在150℃的加熱烘箱中放置30分鐘後，進行將試樣片M冷卻至室溫的處理，測定2根基準線的間隔。將此時測定的處理後的間隔記為A〔mm〕。將由處理前的間隔100mm和處理後的間隔Amm使用“100×（100-A）/100”的式子算出的數值〔%〕作為試樣片M的MD熱收縮率（S）。On the sample piece M cut into a polyester film of 30 mm in the TD direction and 120 mm in the MD direction, two reference lines were drawn in advance so as to reach an interval of 100 mm in the MD direction. The sample piece M was allowed to stand in a heating oven at 150 ° C for 30 minutes under no tension, and then the sample piece M was cooled to room temperature, and the interval between the two reference lines was measured. The interval after the treatment measured at this time was referred to as A [mm]. The numerical value [%] calculated by the equation of "100 × (100 - A) / 100" from the interval before the treatment of 100 mm and the interval Amm after the treatment was taken as the MD heat shrinkage ratio (S) of the sample piece M.

以下，將熱收縮率（150℃、30分鐘）也簡稱為熱收縮率。Hereinafter, the heat shrinkage ratio (150 ° C, 30 minutes) is also simply referred to as a heat shrinkage ratio.

本發明的聚酯膜的與配向方向正交的方向的熱收縮率為配向方向的3點處的在150℃下加熱30分鐘後的與配向方向正交的方向的熱收縮率的平均值。The heat shrinkage ratio in the direction orthogonal to the alignment direction of the polyester film of the present invention is an average value of the heat shrinkage ratio in the direction orthogonal to the alignment direction after heating at 150 ° C for three minutes at three points in the alignment direction.

在本發明中，將膜寬度方向稱為TD或TD方向，將與膜寬度方向正交的方向稱為MD或MD方向。此外，將MD方向的熱收縮也稱為MD熱收縮，將其比例稱為MD熱收縮率。因此，與膜寬度方向正交的方向的熱收縮率也表現為MD熱收縮率。In the present invention, the film width direction is referred to as TD or TD direction, and the direction orthogonal to the film width direction is referred to as MD or MD direction. Further, heat shrinkage in the MD direction is also referred to as MD heat shrinkage, and the ratio thereof is referred to as MD heat shrinkage ratio. Therefore, the heat shrinkage rate in the direction orthogonal to the film width direction also appears as the MD heat shrinkage ratio.

（寬度方向的MD熱收縮率不均）(The MD heat shrinkage rate in the width direction is uneven)

本發明的聚酯膜的由下述式A所表示的寬度方向的MD熱收縮率不均為0.4%以下從寬度方向的熱收縮量差變小、能夠抑制配向方向的破裂的觀點出發是優選的。式A：（與配向方向正交的方向的熱收縮率不均）=（配向方向的3點處的在150℃下加熱30分鐘後的與配向方向正交的方向的熱收縮率的最大值與最小值之差）/（配向方向的3點處的在150℃下加熱30分鐘後的與配向方向正交的方向的熱收縮率的平均值）×100%In the polyester film of the present invention, the MD heat shrinkage ratio in the width direction represented by the following formula A is not more than 0.4%, and the difference in heat shrinkage amount in the width direction is small, and it is preferable to suppress cracking in the alignment direction. of. Formula A: (The heat shrinkage rate unevenness in the direction orthogonal to the alignment direction) = (Maximum value of the heat shrinkage rate in the direction orthogonal to the alignment direction after heating at 150 ° C for 30 minutes at three points in the alignment direction) (the difference from the minimum value) / (the average value of the heat shrinkage rate in the direction orthogonal to the alignment direction after heating at 150 ° C for 3 minutes at 3 points in the alignment direction) × 100%

寬度方向的MD熱收縮率不均進一步優選為0.3%以下，最優選為0.2%以下。The MD heat shrinkage rate unevenness in the width direction is more preferably 0.3% or less, and most preferably 0.2% or less.

（膜平面性）(film planarity)

本發明的聚酯膜的將卷曲成卷狀的聚酯膜的最外表層開卷並切出500mm見方的聚酯膜放置在平面上時的聚酯膜的浮起為1.8mm以下。以下，將卷曲成卷狀的聚酯膜的最外表層開卷並切出500mm見方的聚酯膜放置在平面上時的聚酯膜的浮起（浮的最大值）的情況也稱為膜的平面性。本發明的聚酯膜通過使平面性為1.8mm以下，在搬送輥接觸時膜所受到的應力集中能夠分散，能夠抑制破裂。In the polyester film of the present invention, the outermost surface layer of the polyester film which is crimped into a roll is unwound and the polyester film which is cut into a 500 mm square is placed on a flat surface to have a float of 1.8 mm or less. Hereinafter, the case where the outermost surface layer of the polyester film curled into a roll is unwound and the floating of the polyester film (the maximum value of float) when the 500 mm square polyester film is placed on a flat surface is also referred to as a film. Flatness. When the polyester film of the present invention has a flatness of 1.8 mm or less, the stress concentration of the film when the transfer rolls are in contact with each other can be dispersed, and cracking can be suppressed.

本發明的聚酯膜優選平面性為0～1.0mm，更優選平面性為0～0.5mm。The polyester film of the present invention preferably has a planarity of 0 to 1.0 mm, and more preferably has a planarity of 0 to 0.5 mm.

在求平面性時，將卷曲成卷狀的聚酯膜的最外表層開卷並切出500mm見方的聚酯膜放置在平面上後，到測定聚酯膜的浮起為止的時間優選為低於30分鐘，更優選為低於10分鐘，特別優選為低於5分鐘。In the case of planarity, the outermost surface layer of the polyester film curled into a roll is unwound and the 500 mm square polyester film is cut out on a flat surface, and the time until the measurement of the floating of the polyester film is preferably lower than 30 minutes, more preferably less than 10 minutes, particularly preferably less than 5 minutes.

此外，求平面性時的溫度優選為0～30℃，更優選為10～28℃，特別優選為15～25℃。Further, the temperature at the time of planarity is preferably 0 to 30 ° C, more preferably 10 to 28 ° C, and particularly preferably 15 to 25 ° C.

此外，求平面性時的相對濕度優選為30～80%，更優選為40～70%，特別優選為50～60%。Further, the relative humidity at the time of planarity is preferably from 30 to 80%, more preferably from 40 to 70%, still more preferably from 50 to 60%.

（膜寬度）(film width)

膜寬度W優選為0.8～6.0m，更優選為1～5m，特別優選為1～4m，更特別優選為1～3m。The film width W is preferably 0.8 to 6.0 m, more preferably 1 to 5 m, still more preferably 1 to 4 m, still more preferably 1 to 3 m.

（膜長度）(film length)

本發明的聚酯膜的膜長度優選為100m以上。此外，優選以卷形態卷曲。The film length of the polyester film of the present invention is preferably 100 m or more. Further, it is preferable to curl in a roll form.

膜長度優選為100m以上，更優選為300m以上，進一步優選為500m以上。The film length is preferably 100 m or more, more preferably 300 m or more, and still more preferably 500 m or more.

（折射率、結晶化度）(refractive index, degree of crystallization)

本發明的聚酯膜優選為單軸配向。具體而言，本發明的聚酯膜優選長度方向的折射率為1.590以下、且結晶化度超過5%。The polyester film of the present invention is preferably uniaxially aligned. Specifically, the polyester film of the present invention preferably has a refractive index in the longitudinal direction of 1.590 or less and a degree of crystallization of more than 5%.

本發明的聚酯膜的長度方向的折射率的優選的範圍與未拉伸的聚酯膜的長度方向的折射率的優選的範圍相同。The preferred range of the refractive index in the longitudinal direction of the polyester film of the present invention is the same as the preferred range of the refractive index in the longitudinal direction of the unstretched polyester film.

本發明的聚酯膜的結晶化度優選為5%以上，更優選為20%以上，進一步優選為30%以上。The degree of crystallization of the polyester film of the present invention is preferably 5% or more, more preferably 20% or more, and still more preferably 30% or more.

＜聚酯膜的材料、層構成、表面處理＞<Material, Layer Composition, Surface Treatment of Polyester Film>

本發明的聚酯膜含有聚酯樹脂。The polyester film of the present invention contains a polyester resin.

本發明的聚酯膜可以是以聚酯樹脂為主要成分的層的單層膜，也可以是具有至少1層以聚酯樹脂為主要成分的層的多層膜。此外，也可以是對這些單層膜或多層膜的兩面或單面實施了表面處理的膜，該表面處理可以是利用電暈處理、等離子體處理、皂化處理、熱處理、紫外線照射、電子射線照射等的表面改性，也可以是利用高分子或金屬等的塗布或蒸鍍等的薄膜形成。聚酯樹脂在膜整體中所占的品質比例通常為50質量%以上，優選為70質量%以上，更優選為90質量%以上。The polyester film of the present invention may be a single layer film of a layer mainly composed of a polyester resin, or may be a multilayer film having at least one layer containing a polyester resin as a main component. Further, a film which is surface-treated on both or one side of the single-layer film or the multilayer film may be used, and the surface treatment may be by corona treatment, plasma treatment, saponification treatment, heat treatment, ultraviolet irradiation, or electron beam irradiation. The surface modification may be formed by a film such as coating or vapor deposition of a polymer or a metal. The quality ratio of the polyester resin to the entire film is usually 50% by mass or more, preferably 70% by mass or more, and more preferably 90% by mass or more.

（1-1）聚酯樹脂(1-1) Polyester resin

作為上述的聚酯樹脂，優選使用WO2012/157662號公報的[0042]的組成的聚酯樹脂。As the above polyester resin, a polyester resin having a composition of [0042] of WO2012/157662 is preferably used.

作為聚酯，可以使用聚對苯二甲酸乙二醇酯（PET）、聚萘二甲酸乙二醇酯（PEN）、聚對苯二甲酸丁二醇酯（PBT）、聚對苯二甲酸環己烷二甲醇酯（PCT）等，但從成本、耐熱性出發，更優選為PET、PEN，進一步優選為PET（PEN的Re/Rth稍微容易變小）。As the polyester, polyethylene terephthalate (PET), polyethylene naphthalate (PEN), polybutylene terephthalate (PBT), polyterephthalic acid ring can be used. Although hexane dimethanol ester (PCT) or the like is preferable from the viewpoint of cost and heat resistance, PET and PEN are more preferable, and PET (Re/Rth of PEN is slightly more likely to be small) is more preferable.

聚酯最優選聚對苯二甲酸乙二醇酯，但也可以優選使用聚萘二甲酸乙二醇酯，可以優選使用例如日本特開2008-39803號公報中記載的聚酯。The polyester is most preferably polyethylene terephthalate, but polyethylene naphthalate can also be preferably used, and for example, a polyester described in JP-A-2008-39803 can be preferably used.

聚對苯二甲酸乙二醇酯為具有來自作為二羧酸成分的對苯二甲酸的構成單元、和來自作為二醇成分的乙二醇的構成單元的聚酯，全部重複單元的80摩爾%以上為對苯二甲酸乙二醇酯較佳，也可以包含來自其他的共聚成分的構成單元。作為其他的共聚成分，可列舉出間苯二甲酸、對β-羥基乙氧基苯甲酸、4,4’-二羧基聯苯、4,4’-二羧基二苯甲酮、雙（4-羧基苯基）乙烷、己二酸、癸二酸、間苯二甲酸-5-磺酸鈉、1,4-二羧基環己烷等二羧酸成分、丙二醇、丁二醇、新戊二醇、二乙二醇、環己烷二醇、雙酚A的環氧乙烷加成物、聚乙二醇、聚丙二醇、聚四亞甲基二醇等二醇成分。這些二羧酸成分、二醇成分根據需要可以將兩種以上組合使用。此外，也可以與上述羧酸成分、二醇成分一起並用對羥基苯甲酸等羥基羧酸。作為其他的共聚成分，也可以使用含有少量的醯胺鍵、氨基甲酸酯鍵、醚鍵、碳酸酯鍵等的二羧酸成分和/或二醇成分。作為聚對苯二甲酸乙二醇酯的製造法，可以應用使對苯二甲酸與乙二醇、以及根據需要而使用的其他的二羧酸和/或其他的二醇直接反應的所謂的直接聚合法、使對苯二甲酸的二甲基酯與乙二醇、以及根據需要而使用的其他的二羧酸的二甲基酯和/或其他的二醇進行酯交換反應的所謂的酯交換反應法等任意的製造法。Polyethylene terephthalate is a polyester having a constituent unit derived from terephthalic acid as a dicarboxylic acid component and a constituent unit derived from ethylene glycol as a glycol component, and 80 mol% of all repeating units The above is preferably ethylene terephthalate, and may also contain constituent units derived from other copolymerization components. Examples of other copolymerization components include isophthalic acid, β-hydroxyethoxybenzoic acid, 4,4′-dicarboxybiphenyl, 4,4′-dicarboxybenzophenone, and bis(4- Carboxyphenyl) ethane, adipic acid, sebacic acid, sodium isophthalate-5-sulfonate, dicarboxylic acid components such as 1,4-dicarboxycyclohexane, propylene glycol, butanediol, neopentyl A diol component such as an alcohol, diethylene glycol, cyclohexanediol, an ethylene oxide adduct of bisphenol A, polyethylene glycol, polypropylene glycol, or polytetramethylene glycol. These dicarboxylic acid components and diol components can be used in combination of 2 or more types as needed. Further, a hydroxycarboxylic acid such as p-hydroxybenzoic acid may be used in combination with the above carboxylic acid component or diol component. As the other copolymerization component, a dicarboxylic acid component and/or a diol component containing a small amount of a guanamine bond, a urethane bond, an ether bond, a carbonate bond or the like can also be used. As a method for producing polyethylene terephthalate, so-called direct reaction of terephthalic acid with ethylene glycol and, if necessary, other dicarboxylic acids and/or other diols can be directly used. The so-called transesterification of a transesterification reaction of a dimethyl ester of terephthalic acid with ethylene glycol and, if necessary, other dimethyl esters of a dicarboxylic acid and/or other diol Any manufacturing method such as a reaction method.

（1-2）聚酯樹脂的物性(1-2) Physical properties of polyester resin

（1-2-1）特性粘度(1-2-1) Intrinsic viscosity

聚酯樹脂的特性粘度IV優選為0.5以上且0.9以下，更優選為0.52以上且0.8以下，進一步優選為0.54以上且0.7以下。為了達到這樣的IV，在合成聚酯樹脂時，除了後述的熔融聚合以外，還可以並用固相聚合。The intrinsic viscosity IV of the polyester resin is preferably 0.5 or more and 0.9 or less, more preferably 0.52 or more and 0.8 or less, still more preferably 0.54 or more and 0.7 or less. In order to achieve such IV, in the synthesis of the polyester resin, in addition to the melt polymerization described later, solid phase polymerization may be used in combination.

（1-2-2）乙醛含有率(1-2-2) Acetaldehyde content rate

聚酯樹脂的乙醛含量優選為50ppm以下。進一步優選為40ppm以下，特別優選為30ppm以下。乙醛有時在乙醛彼此間容易引起縮合反應，作為副反應產物生成水，通過該水，進行聚酯的水解。乙醛含量的下限現實中為1ppm左右。為了使乙醛含量為上述範圍，可以採用以下方法：將樹脂的製造時的熔融聚合、固相聚合等各步驟中的氧濃度保持較低；將樹脂保管時、乾燥時的氧濃度保持較低；降低在膜製造時由擠出機、熔體配管、模等對樹脂施加的熱歷程；防止因熔融時的擠出機的螺杆構成等局部地受到強剪切等。The acetaldehyde content of the polyester resin is preferably 50 ppm or less. More preferably, it is 40 ppm or less, and it is especially preferable that it is 30 ppm or less. Acetaldehyde sometimes causes a condensation reaction between acetaldehydes, and water is produced as a side reaction product, and hydrolysis of the polyester is carried out by the water. The lower limit of the acetaldehyde content is actually about 1 ppm. In order to make the acetaldehyde content in the above range, the oxygen concentration in each step such as melt polymerization or solid phase polymerization in the production of the resin is kept low, and the oxygen concentration during storage and drying is kept low. The heat history applied to the resin by an extruder, a melt pipe, a die, or the like at the time of film production is reduced, and strong shearing or the like is locally prevented by the screw structure of the extruder at the time of melting.

（1-3）催化劑(1-3) Catalyst

在聚酯樹脂的聚合中，可使用Sb、Ge、Ti、Al系催化劑，優選為Sb、Ti、Al系催化劑，進一步優選為Al系催化劑。In the polymerization of the polyester resin, Sb, Ge, Ti, or an Al-based catalyst can be used, and a Sb, Ti, or Al-based catalyst is preferable, and an Al-based catalyst is more preferable.

即，作為原料樹脂使用的聚酯樹脂優選為使用鋁催化劑聚合而成的聚酯樹脂。That is, the polyester resin used as the raw material resin is preferably a polyester resin obtained by polymerization using an aluminum catalyst.

通過使用Al系催化劑，與使用其他的催化劑（例如Sb、Ti）的情況相比，Re變得容易顯現，PET的輕薄化成為可能。即，意味著Al系催化劑更容易配向。推測其基於以下的理由。By using an Al-based catalyst, Re becomes easier to visualize than in the case of using another catalyst (for example, Sb or Ti), and it is possible to reduce the thickness of PET. That is, it means that the Al-based catalyst is more easily aligned. It is assumed that it is based on the following reasons.

Al系催化劑與Sb、Ti相比，反應性（聚合活性）低，反應溫和，難以生成副產物（二乙二醇單元：DEG）。The Al-based catalyst has lower reactivity (polymerization activity) than Sb and Ti, and the reaction is mild, and it is difficult to form a by-product (diethylene glycol unit: DEG).

其結果是，PET的規整性提高，容易配向且容易顯現Re。As a result, the regularity of PET is improved, it is easy to align and it is easy to show Re.

（1-3-1）Al系催化劑(1-3-1) Al-based catalyst

作為上述的Al系催化劑，可以引用WO2011/040161號公報的[0013]～[0148]（US2012/0183761號公報的[0021]～[0123]）中記載的Al系催化劑來使用，這些公報中記載的內容被納入本說明書中。As the above-mentioned Al-based catalyst, the Al-based catalyst described in [0013] to [0148] of WO2011/040161 ([0021] to [0123] of US2012/0183761) can be used, and these publications are described. The content is included in this manual.

作為使用上述的Al系催化劑將聚酯樹脂聚合的方法，沒有特別限制，具體而言，可以引用WO2012/008488號公報的[0091]～[0094]（US2013/0112271號公報的[0144]～[0153]），按照這些公報來聚合，這些公報中記載的內容被納入本說明書中。The method of polymerizing the polyester resin using the above-described Al-based catalyst is not particularly limited, and specifically, [0091] to [0094] of WO2012/008488 (Japanese Patent Publication No. 2013/0112271) [0144] to [ 0153]), according to these publications, the contents described in these publications are incorporated in the present specification.

這樣的Al系催化劑可以引用例如日本特開2012-122051號公報的[0052]～[0054]、[0099]～[0104]（WO2012/029725號公報的[0045]～[0047]、[0091]～[0096]），按照這些公報來製備，這些公報中記載的內容被納入本說明書中。Al系催化劑量以Al元素相對於聚酯樹脂的品質的量計優選為3～80ppm，更優選為5～60ppm，進一步優選為5～40ppm。For example, [0052] to [0054], [0099] to [0104] of the Japanese Patent Publication No. 2012-122051 (WO2012/029725, [0045] to [0047], [0091] ~ [0096]), prepared in accordance with these publications, the contents described in these publications are incorporated in the present specification. The amount of the Al-based catalyst is preferably from 3 to 80 ppm, more preferably from 5 to 60 ppm, even more preferably from 5 to 40 ppm, based on the mass of the Al element to the polyester resin.

（1-3-2）Sb系催化劑：(1-3-2) Sb catalyst:

作為上述的Sb系催化劑，可以使用日本特開2012-41519號公報的[0050]、[0052]～[0054]中記載的Sb系催化劑。As the Sb-based catalyst, the Sb-based catalysts described in [0050] and [0052] to [0054] of JP-A-2012-41519 can be used.

作為使用上述的Sb系催化劑將聚酯樹脂聚合的方法，沒有特別限制，具體而言，可以按照WO2012/157662號公報的[0086]～[0087]來聚合。The method of polymerizing the polyester resin using the above-described Sb-based catalyst is not particularly limited, and specifically, it can be polymerized according to [0086] to [0087] of WO2012/157662.

（1-4）添加劑：(1-4) Additives:

還優選在本發明的聚酯膜中添加公知的添加劑。作為其例子，可列舉出紫外線吸收劑、粒子、滑劑、防粘連劑、熱穩定劑、抗氧化劑、抗靜電劑、耐光劑、耐衝擊性改良劑、潤滑劑、染料、顏料等。其中，由於聚酯膜通常需要透明性，所以添加劑的添加量優選限制在最小限度。It is also preferred to add a known additive to the polyester film of the present invention. Examples thereof include ultraviolet absorbers, particles, slip agents, antiblocking agents, heat stabilizers, antioxidants, antistatic agents, light stabilizers, impact modifiers, lubricants, dyes, and pigments. Among them, since the polyester film generally requires transparency, the amount of the additive to be added is preferably limited to a minimum.

（1-4-1）紫外線（UV）吸收劑：(1-4-1) Ultraviolet (UV) absorber:

為了防止液晶顯示器的液晶等因紫外線而劣化，本發明的聚酯膜中也可以含有紫外線吸收劑。紫外線吸收劑只要是具有紫外線吸收能力的化合物、且可耐受在聚酯膜的製造步驟中附加的熱的化合物，則沒有特別限定。In order to prevent deterioration of the liquid crystal or the like of the liquid crystal display due to ultraviolet rays, the polyester film of the present invention may contain an ultraviolet absorber. The ultraviolet absorber is not particularly limited as long as it is a compound having an ultraviolet absorbing ability and is resistant to heat added in the production process of the polyester film.

作為紫外線吸收劑，有有機系紫外線吸收劑和無機系紫外線吸收劑，但從透明性的觀點出發，優選有機系紫外線吸收劑。可以使用WO2012/157662號公報的[0057]中記載的紫外線吸收劑、後述的環狀亞氨基酯系的紫外線吸收劑。The ultraviolet absorber is an organic ultraviolet absorber and an inorganic ultraviolet absorber. From the viewpoint of transparency, an organic ultraviolet absorber is preferred. The ultraviolet absorber described in [0057] of WO2012/157662, and the cyclic imido ester-based ultraviolet absorber described later can be used.

作為環狀亞氨基酯系的紫外線吸收劑，並不限定於下述的物質，可列舉出例如2-甲基-3,1-苯並噁嗪-4-酮、2-丁基-3,1-苯並噁嗪-4-酮、2-苯基-3,1-苯並噁嗪-4-酮、2-（1-或2-萘基）-3,1-苯並噁嗪-4-酮、2-（4-聯苯基）-3,1-苯並噁嗪-4-酮、2-對硝基苯基-3,1-苯並噁嗪-4-酮、2-間硝基苯基-3,1-苯並噁嗪-4-酮、2-對苯甲醯基苯基-3,1-苯並噁嗪-4-酮、2-對甲氧基苯基-3,1-苯並噁嗪-4-酮、2-鄰甲氧基苯基-3,1-苯並噁嗪-4-酮、2-環己基-3,1-苯並噁嗪-4-酮、2-對（或間）鄰苯二甲醯亞胺苯基-3,1-苯並噁嗪-4-酮、N-苯基-4-（3,1-苯並噁嗪-4-酮-2-基）鄰苯二甲醯亞胺、N-苯甲醯基-4-（3,1-苯並噁嗪-4-酮-2-基）苯胺、N-苯甲醯基-N-甲基-4-（3,1-苯並噁嗪-4-酮-2-基）苯胺、2-（對（N-甲基羰基）苯基）-3,1-苯並噁嗪-4-酮、2,2’-雙（3,1-苯並噁嗪-4-酮）、2,2’-亞乙基雙（3,1-苯並噁嗪-4-酮）、2,2’-四亞甲基雙（3,1-苯並噁嗪-4-酮）、2,2’-十亞甲基雙（3,1-苯並噁嗪-4-酮、2,2’-（1,4-亞苯基）雙（4H-3,1-苯並噁嗪-4-酮）〔另外，也稱為2,2’-對亞苯基雙（3,1-苯並噁嗪-4-酮）〕、2,2’-間亞苯基雙（3,1-苯並噁嗪-4-酮）、2,2’-（4,4’-二亞苯基）雙（3,1-苯並噁嗪-4-酮）、2,2’-（2,6-或1,5-亞萘基）雙（3,1-苯並噁嗪-4-酮）、2,2’-（2-甲基-對亞苯基）雙（3,1-苯並噁嗪-4-酮）、2,2’-（2-硝基-對亞苯基）雙（3,1-苯並噁嗪-4-酮）、2,2’-（2-氯-對亞苯基）雙（3,1-苯並噁嗪-4-酮）、2,2’-（1,4-環亞己基）雙（3,1-苯並噁嗪-4-酮）、1,3,5-三（3,1-苯並噁嗪-4-酮-2-基）苯、1,3,5-三（3,1-苯並噁嗪-4-酮-2-基）萘、2,4,6-三（3,1-苯並噁嗪-4-酮-2-基）萘、2,8-二甲基-4H,6H-苯並（1,2-d；5,4-d’）雙（1,3）-噁嗪-4,6-二酮、2,7-二甲基-4H,9H-苯並（1,2-d；4,5-d’）雙（1,3）-噁嗪-4,9-二酮、2,8-二苯基-4H,8H-苯並（1,2-d；5,4-d’）雙（1,3）-噁嗪-4,6-二酮、2,7-二苯基-4H,9H-苯並（1,2-d；4,5-d’）雙（1,3）-噁嗪-4,6-二酮、6,6’-雙（2-甲基-4H,3,1-苯並噁嗪-4-酮）、6,6’-雙（2-乙基-4H,3,1-苯並噁嗪-4-酮）、6,6’-雙（2-苯基-4H,3,1-苯並噁嗪-4-酮）、6,6’-亞甲基雙（2-甲基-4H,3,1-苯並噁嗪-4-酮）、6,6’-亞甲基雙（2-苯基-4H,3,1-苯並噁嗪-4-酮）、6,6’-亞乙基雙（2-甲基-4H,3,1-苯並噁嗪-4-酮）、6,6’-亞乙基雙（2-苯基-4H,3,1-苯並噁嗪-4-酮）、6,6’-亞丁基雙（2-甲基-4H,3,1-苯並噁嗪-4-酮）、6,6’-亞丁基雙（2-苯基-4H,3,1-苯並噁嗪-4-酮）、6,6’-氧基雙（2-甲基-4H,3,1-苯並噁嗪-4-酮）、6,6’-氧基雙（2-苯基-4H,3,1-苯並噁嗪-4-酮）、6,6’-磺醯基雙（2-甲基-4H,3,1-苯並噁嗪-4-酮）、6,6’-磺醯基雙（2-苯基-4H,3,1-苯並噁嗪-4-酮）、6,6’-羰基雙（2-甲基-4H,3,1-苯並噁嗪-4-酮）、6,6’-羰基雙（2-苯基-4H,3,1-苯並噁嗪-4-酮）、7,7’-亞甲基雙（2-甲基-4H,3,1-苯並噁嗪-4-酮）、7,7’-亞甲基雙（2-苯基-4H,3,1-苯並噁嗪-4-酮）、7,7’-雙（2-甲基-4H,3,1-苯並噁嗪-4-酮）、7,7’-亞乙基雙（2-甲基-4H,3,1-苯並噁嗪-4-酮）、7,7’-氧基雙（2-甲基-4H,3,1-苯並噁嗪-4-酮）、7,7’-磺醯基雙（2-甲基-4H,3,1-苯並噁嗪-4-酮）、7,7’-羰基雙（2-甲基-4H,3,1-苯並噁嗪-4-酮）、6,7’-雙（2-甲基-4H,3,1-苯並噁嗪-4-酮）、6,7’-雙（2-苯基-4H,3,1-苯並噁嗪-4-酮、6,7’-亞甲基雙（2-甲基-4H,3,1-苯並噁嗪-4-酮）、6,7’-亞甲基雙（2-苯基-4H,3,1-苯並噁嗪-4-酮）等。The ultraviolet absorbing agent of the cyclic imino ester type is not limited to the following, and examples thereof include 2-methyl-3,1-benzoxazin-4-one and 2-butyl-3. 1-benzoxazine-4-one, 2-phenyl-3,1-benzoxazin-4-one, 2-(1- or 2-naphthyl)-3,1-benzoxazine- 4-keto, 2-(4-biphenyl)-3,1-benzoxazin-4-one, 2-p-nitrophenyl-3,1-benzoxazin-4-one, 2- m-Nitrophenyl-3,1-benzoxazin-4-one, 2-p-benzoylphenyl-3,1-benzoxazin-4-one, 2-p-methoxyphenyl -3,1-benzoxazin-4-one, 2-o-methoxyphenyl-3,1-benzoxazin-4-one, 2-cyclohexyl-3,1-benzoxazine- 4-keto, 2-p-(or m-o-phthalimide phenyl-3,1-benzoxazin-4-one, N-phenyl-4-(3,1-benzoxazine) 4-keto-2-yl)phthalic acid imide, N-benzylidene-4-(3,1-benzoxazin-4-one-2-yl)aniline, N-benzoic acid Mercapto-N-methyl-4-(3,1-benzoxazin-4-one-2-yl)aniline, 2-(p-(N-methylcarbonyl)phenyl)-3,1-benzene And oxazin-4-one, 2,2'-bis(3,1-benzoxazin-4-one), 2,2'-ethylenebis(3,1-benzoxazine-4- Ketone), 2,2'-tetramethylene Bis(3,1-benzoxazin-4-one), 2,2'-decamethylenebis(3,1-benzoxazin-4-one, 2,2'-(1,4- Phenylene) bis(4H-3,1-benzoxazin-4-one) [Additionally, also known as 2,2'-p-phenylenebis(3,1-benzoxazin-4-one) )], 2,2'-m-phenylenebis(3,1-benzoxazin-4-one), 2,2'-(4,4'-diphenylene) bis (3,1- Benzoxazine-4-one), 2,2'-(2,6- or 1,5-naphthylene)bis(3,1-benzoxazin-4-one), 2,2'- (2-methyl-p-phenylene) bis(3,1-benzoxazin-4-one), 2,2'-(2-nitro-p-phenylene) bis(3,1-benzene And oxazin-4-one), 2,2'-(2-chloro-p-phenylene) bis(3,1-benzoxazin-4-one), 2,2'-(1,4- Cyclohexylene) bis(3,1-benzoxazin-4-one), 1,3,5-tris(3,1-benzoxazin-4-one-2-yl)benzene, 1,3 ,5-tris(3,1-benzoxazin-4-one-2-yl)naphthalene, 2,4,6-tris(3,1-benzoxazin-4-one-2-yl)naphthalene , 2,8-Dimethyl-4H,6H-benzo(1,2-d;5,4-d')bis(1,3)-oxazine-4,6-dione, 2,7- Dimethyl-4H,9H-benzo(1,2-d;4,5-d')bis(1,3)-oxazine-4,9-dione, 2,8-diphenyl-4H , 8H -Benzo(1,2-d;5,4-d')bis(1,3)-oxazine-4,6-dione, 2,7-diphenyl-4H,9H-benzo (1) ,2-d;4,5-d') bis(1,3)-oxazine-4,6-dione, 6,6'-bis(2-methyl-4H,3,1-benzaldehyde Pyridazin-4-one), 6,6'-bis(2-ethyl-4H,3,1-benzoxazin-4-one), 6,6'-bis(2-phenyl-4H,3 , 1-benzoxazine-4-one), 6,6'-methylenebis(2-methyl-4H,3,1-benzoxazin-4-one), 6,6'-Asia Methyl bis(2-phenyl-4H,3,1-benzoxazin-4-one), 6,6'-ethylene bis(2-methyl-4H,3,1-benzoxazine 4-keto), 6,6'-ethylenebis(2-phenyl-4H,3,1-benzoxazin-4-one), 6,6'-butylene bis(2-methyl -4H,3,1-benzoxazin-4-one), 6,6'-butylene bis(2-phenyl-4H,3,1-benzoxazin-4-one), 6,6 '-oxybis(2-methyl-4H,3,1-benzoxazin-4-one), 6,6'-oxybis(2-phenyl-4H,3,1-benzaldehyde Pyridazin-4-one), 6,6'-sulfonyl bis(2-methyl-4H,3,1-benzoxazin-4-one), 6,6'-sulfonyl bis (2- Phenyl-4H,3,1-benzoxazin-4-one), 6,6'-carbonylbis(2-methyl-4H,3,1-benzoxazin-4-one), 6, 6'-carbonyl bis(2-benzene -4H,3,1-benzoxazin-4-one), 7,7'-methylenebis(2-methyl-4H,3,1-benzoxazin-4-one), 7, 7'-methylenebis(2-phenyl-4H,3,1-benzoxazin-4-one), 7,7'-bis(2-methyl-4H,3,1-benzaldehyde Pyrazin-4-one), 7,7'-ethylenebis(2-methyl-4H,3,1-benzoxazin-4-one), 7,7'-oxybis(2-methyl) -4H,3,1-benzoxazin-4-one), 7,7'-sulfonyl bis(2-methyl-4H,3,1-benzoxazin-4-one), 7 ,7'-carbonylbis(2-methyl-4H,3,1-benzoxazin-4-one), 6,7'-bis(2-methyl-4H,3,1-benzoxazine 4-keto), 6,7'-bis(2-phenyl-4H,3,1-benzoxazin-4-one, 6,7'-methylenebis(2-methyl-4H, 3,1-Benzoxazine-4-one), 6,7'-methylenebis(2-phenyl-4H,3,1-benzoxazin-4-one) and the like.

上述化合物中，考慮色調的情況下，適宜使用不易黃化的苯並噁嗪酮系的化合物，作為其例子，更適宜使用下述通式（1）所表示的化合物。In the case of considering the color tone, a benzoxazinone-based compound which is not easily yellowed is preferably used. As an example, a compound represented by the following formula (1) is more preferably used.

[化學式1][Chemical Formula 1]

通式（1） General formula (1)

上述通式（1）中，R表示2價的芳香族烴基，X¹ 及X² 分別獨立地選自氫或以下的官能團組，但並不限定於它們。In the above formula (1), R represents a divalent aromatic hydrocarbon group, and X ¹ and X ² are each independently selected from hydrogen or a functional group of the following, but are not limited thereto.

官能團組：烷基、芳基、雜芳基、鹵素、烷氧基、芳氧基、羥基、羧基、酯基、硝基。Group of functional groups: alkyl, aryl, heteroaryl, halogen, alkoxy, aryloxy, hydroxy, carboxy, ester, nitro.

上述通式（1）所表示的化合物中，在本發明中，特別優選2,2’-（1,4-亞苯基）雙（4H-3,1-苯並噁嗪-4-酮）。Among the compounds represented by the above formula (1), in the present invention, 2,2'-(1,4-phenylene)bis(4H-3,1-benzoxazin-4-one) is particularly preferred. .

本發明的聚酯膜中含有的紫外線吸收劑的量通常為10.0品質%以下，優選在0.3～3.0品質%的範圍內含有。含有超過10.0品質%的量的紫外線吸收劑的情況下，紫外線吸收劑滲出到表面，有可能導致膠粘性降低等表面功能性的惡化。The amount of the ultraviolet absorber contained in the polyester film of the present invention is usually 10.0% by mass or less, and preferably 0.3% to 3.0% by mass. In the case of an ultraviolet absorber containing an amount of more than 10.0% by mass, the ultraviolet absorber bleeds out to the surface, which may cause deterioration of surface functionality such as a decrease in adhesiveness.

此外，在多層結構的本發明的聚酯膜的情況下，優選至少3層結構的聚酯膜，紫外線吸收劑優選配合到其中間層中。通過在中間層中配合紫外線吸收劑，能夠防止該化合物向膜表面滲出，其結果是，能夠維持膜的膠粘性等特性。Further, in the case of the polyester film of the present invention having a multilayer structure, a polyester film of at least three layers is preferred, and the ultraviolet absorber is preferably incorporated into the intermediate layer thereof. By blending the ultraviolet absorber in the intermediate layer, it is possible to prevent the compound from oozing out to the surface of the film, and as a result, properties such as adhesiveness of the film can be maintained.

對於它們的配合，可以利用WO2011/162198號公報的[0050]～[0051]中記載的母料法。For the blending thereof, the master batch method described in [0050] to [0051] of WO2011/162198 can be used.

（1-4-2）其他添加劑(1-4-2) Other additives

在本發明的聚酯膜中也可以使用其他添加劑，可以引用例如WO2012/157662號公報的[0058]中記載的添加劑來使用，這些公報中記載的內容被納入本說明書中。In the polyester film of the present invention, other additives may be used, and the additives described in, for example, [0058] of WO2012/157662 may be used, and the contents described in these publications are incorporated in the present specification.

[聚酯膜的製造方法][Method for Producing Polyester Film]

作為本發明的聚酯膜的製造方法，沒有特別限制，本發明的聚酯膜可以通過公知的方法來製造。The method for producing the polyester film of the present invention is not particularly limited, and the polyester film of the present invention can be produced by a known method.

本發明的聚酯膜通過以下的本發明的聚酯膜的製造方法的第1方式及第2方式，可以以良好的生產率進行製造。The polyester film of the present invention can be produced with good productivity by the first aspect and the second aspect of the method for producing a polyester film of the present invention described below.

本發明的聚酯膜的製造方法的第1方式包括以下步驟：使用具有多個邊夾持膜邊在一對軌道間移動的夾子的拉伸機，在各軌道上同時進行由縮短上述的夾子間的距離引起的向膜搬送方向的收縮、和由擴大上述的夾子移動的一對軌道間的距離引起的向與膜搬送方向正交的方向的拉伸的步驟，A first aspect of the method for producing a polyester film of the present invention includes the step of simultaneously shortening the above-described clips on each of the rails by using a stretching machine having a plurality of clips that sandwich the film while moving between the pair of rails. a step of contracting in the film transport direction by the distance between the two, and a step of stretching in a direction orthogonal to the film transport direction due to a distance between the pair of rails that expand the above-described clip movement,

上述的向膜搬送方向的收縮率和向與膜搬送方向正交的方向的拉伸倍率在拉伸中總是滿足下述式B1的關係，並且滿足下述式B2及式B3。The shrinkage ratio in the film transport direction and the draw ratio in the direction orthogonal to the film transport direction always satisfy the relationship of the following formula B1 during stretching, and satisfy the following formulas B2 and B3.

本發明的聚酯膜的製造方法的第2方式是包括以下步驟：使用具有多個邊夾持膜邊在一對軌道間移動的夾子的拉伸機，在各軌道上同時進行由縮短上述的夾子間的距離引起的向膜搬送方向的收縮、和由擴大上述的夾子移動的一對軌道間的距離引起的向與膜搬送方向正交的方向的拉伸的步驟，A second aspect of the method for producing a polyester film of the present invention comprises the steps of: simultaneously shortening the above-described stretching by using a stretching machine having a plurality of clips that sandwich a film while moving between a pair of rails a step of contracting in the film transport direction by the distance between the clips and stretching in a direction orthogonal to the film transport direction by a distance between the pair of rails that expand the above-described clip movement,

上述的向膜搬送方向的收縮率和向與膜搬送方向正交的方向的拉伸倍率在拉伸中總是滿足下述式B1的關係、並且滿足下述式B2及式B3聚酯膜的製造方法，The shrinkage ratio in the film transport direction and the draw ratio in the direction orthogonal to the film transport direction always satisfy the relationship of the following formula B1 during stretching, and satisfy the polyester film of the following formula B2 and formula B3. Production method,

上述的聚酯膜的厚度為10～150μm，The above polyester film has a thickness of 10 to 150 μm.

上述的聚酯膜的與配向方向正交的方向的熱收縮率為0.6%以下。 [數學式7]･･･式B1 [數學式8]･･･式B2 [數學式9]･･･式B3The heat shrinkage ratio of the above-mentioned polyester film in the direction orthogonal to the alignment direction is 0.6% or less. [Math 7] ・・・式B1 [Math 8] ・・・式B2 [Math 9] ・・・式B3

式B1、B2及B3中，In Equations B1, B2, and B3,

以下，對本發明的聚酯膜的製造方法的優選的方式進行說明。Hereinafter, a preferred embodiment of the method for producing a polyester film of the present invention will be described.

＜熔融混煉＞<Molten mixing>

未拉伸的聚酯膜優選將聚酯樹脂進行熔融擠出並以膜狀成形而成。The unstretched polyester film is preferably obtained by melt-extruding a polyester resin and forming it in a film form.

優選在將聚酯樹脂、或通過上述的母料法製造的聚酯樹脂和添加劑的母料乾燥至含水率為200ppm以下後，導入單軸或雙軸的擠出機使其熔融。此時，為了抑制聚酯的分解，還優選在氮氣中或真空中進行熔融。詳細的條件引用日本專利4962661號的[0051]～[0052]（US2013/0100378號公報的[0085]～[0086]），可以按照這些公報來實施，這些公報中記載的內容被納入本說明書中。進而，為了提高熔融樹脂（熔體）的送出精度，還優選使用齒輪泵。此外，還優選使用用於除去雜質的3μm～20μm的過濾機。Preferably, the masterbatch of the polyester resin or the polyester resin and the additive produced by the above-described master batch method is dried to a water content of 200 ppm or less, and then introduced into a uniaxial or biaxial extruder to be melted. At this time, in order to suppress decomposition of the polyester, it is also preferred to carry out the melting in nitrogen or in a vacuum. [0051] to [0052] (Japanese Patent Publication No. [0085] to [0086] of US2013/0100378), which can be carried out in accordance with these publications, the contents of which are incorporated in the specification. . Further, in order to improve the accuracy of the delivery of the molten resin (melt), it is preferable to use a gear pump. Further, it is also preferred to use a filter of 3 μm to 20 μm for removing impurities.

＜擠出、共擠出＞<Extrusion, coextrusion>

優選將包含經熔融混煉的聚酯樹脂的熔體從模擠出，可以以單層擠出，也可以以多層擠出。在以多層擠出的情況下，例如可以將含有紫外線吸收劑（UV劑）的層和不含有紫外線吸收劑的層層疊，更優選使UV劑作為內層的3層構成可抑制由紫外線引起的偏振片的劣化，並且抑制UV劑的滲出，優選。The melt containing the melt-kneaded polyester resin is preferably extruded from a die, and may be extruded in a single layer or in a plurality of layers. In the case of extrusion in a plurality of layers, for example, a layer containing an ultraviolet absorber (UV agent) and a layer not containing an ultraviolet absorber may be laminated, and it is more preferable to form a three-layer structure in which a UV agent is used as an inner layer to suppress ultraviolet rays. Deterioration of the polarizing plate and suppression of bleeding of the UV agent are preferred.

滲出的UV劑轉印到工制膜步驟的軋輥上，增加膜與輥的摩擦係數而容易產生擦傷，不優選。The oozing UV agent is transferred to the roll of the film forming step, and the friction coefficient of the film and the roll is increased to cause scratching, which is not preferable.

在聚酯膜以多層擠出製造而成的情況下，所得到的聚酯膜的優選的內層的厚度（相對於全層的比率）優選為50%以上且95%以下，更優選為60%以上且90%以下，進一步優選為70%以上且85%以下。這樣的層疊可以通過使用送料模或多歧管模來實施。In the case where the polyester film is produced by multilayer extrusion, the thickness of the preferred inner layer of the obtained polyester film (ratio with respect to the entire layer) is preferably 50% or more and 95% or less, more preferably 60. % or more and 90% or less, more preferably 70% or more and 85% or less. Such lamination can be carried out by using a feed mold or a multi-manifold mold.

＜流延＞<casting>

優選按照日本特開2009-269301號公報的[0059]，將從模擠出的熔體擠出到流延鼓上，冷卻固化，得到未拉伸的聚酯膜（坯料）。The melt extruded from the die is extruded onto a casting drum, and solidified by cooling to obtain an unstretched polyester film (blank), in accordance with [0059] of JP-A-2009-269301.

在本發明的聚酯膜的製造方法中，上述的未拉伸的聚酯膜的長度方向的折射率優選為1.590以下，更優選為1.585以下，進一步優選為1.580以下。In the method for producing a polyester film of the present invention, the refractive index in the longitudinal direction of the unstretched polyester film is preferably 1.590 or less, more preferably 1.585 or less, still more preferably 1.580 or less.

在本發明的聚酯膜的製造方法中，上述的未拉伸的聚酯膜的結晶化度優選為5%以下，更優選為3%以下，進一步優選為1%以下。另外，這裡所謂的未拉伸的聚酯膜的結晶化度是指膜寬度方向的中央部的結晶化度。In the method for producing a polyester film of the present invention, the degree of crystallization of the above-mentioned unstretched polyester film is preferably 5% or less, more preferably 3% or less, still more preferably 1% or less. In addition, the degree of crystallization of the unstretched polyester film herein means the degree of crystallization in the central portion in the film width direction.

在調整結晶化度時，可以稍微降低流延鼓的端部的溫度，或者對流延鼓上送風。When the degree of crystallization is adjusted, the temperature of the end portion of the casting drum can be slightly lowered, or the casting drum can be blown.

關於結晶化度，可以由膜的密度算出。即，可以使用膜的密度X（g/cm³ ）、結晶化度為0%時的密度Y=1.335g/cm³ 、結晶化度為100%時的密度Z=1.501g/cm³ 由下述計算式匯出結晶化度（%）。The degree of crystallization can be calculated from the density of the film. That is, using a film density X (g / cm ^3), crystallinity of 0% of the density of Y = 1.335g / cm ^3, a crystallinity of 100% of the density of Z = 1.501g / cm ³ by the The calculation formula recurs the degree of crystallization (%).

結晶化度={Z × （X-Y）}/{X × （Z-Y）}×100Crystallization degree = {Z × (X-Y)} / {X × (Z-Y)} × 100

另外，密度的測定根據JIS K7112進行測定。Further, the density was measured in accordance with JIS K7112.

＜聚合物層（易膠粘層）的形成＞<Formation of polymer layer (adhesive layer)>

在熔融擠出的未拉伸的聚酯膜上，也可以在後述的拉伸之前或之後通過塗布而形成聚合物層（優選易膠粘層）。On the melt-extruded unstretched polyester film, a polymer layer (preferably an easy-adhesive layer) may be formed by coating before or after stretching as described later.

作為上述的聚合物層，通常可列舉出偏振板可以具有的功能層，其中，作為上述的聚合物層，優選形成易膠粘層。易膠粘層可以通過WO2012/157662號公報的[0062]～[0070]中記載的方法來塗設。The polymer layer described above generally includes a functional layer which the polarizing plate can have. Among them, it is preferable to form an easy-adhesive layer as the above polymer layer. The easy-adhesive layer can be applied by the method described in [0062] to [0070] of WO2012/157662.

＜橫向拉伸＞<lateral stretching>

本發明的聚酯膜的製造方法包括使用具有多個邊夾持膜邊在一對軌道間移動的夾子的拉伸機，在各軌道上同時進行由縮短上述的夾子間的距離引起的向膜搬送方向的收縮、和由擴大上述的夾子移動的一對軌道間的距離引起的向與膜搬送方向正交的方向的拉伸的步驟，上述的向膜搬送方向的收縮率和向與膜搬送方向正交的方向的拉伸倍率在拉伸中總是滿足下述式B1的關係，並且滿足下述式B2及式B3。 [數學式10]･･･式B1 [數學式11]･･･式B2 [數學式12]･･･式B3The method for producing a polyester film of the present invention comprises using a stretching machine having a plurality of clips that sandwich a film while moving between a pair of rails, and simultaneously performing a film on the respective tracks by shortening the distance between the clips described above. The contraction in the transport direction and the step of stretching in a direction orthogonal to the film transport direction by the distance between the pair of rails that expand the above-described clip movement, the above-described shrinkage rate in the film transport direction and transport to the film The stretching ratio in the direction orthogonal to the direction always satisfies the relationship of the following formula B1 in stretching, and satisfies the following formulas B2 and B3. [Math 10] ・・・式B1 [Mathematical 11] ・・・式B2 [Math 12] ・・・式B3

式B1、B2及B3中，In Equations B1, B2, and B3,

在本說明書中，將使用具有多個邊夾持膜邊在一對軌道間移動的夾子的拉伸機，在各軌道上同時進行由縮短上述的夾子間的距離引起的向膜搬送方向的收縮、和由擴大上述的夾子移動的一對軌道間的距離引起的向與膜搬送方向正交的方向的拉伸的步驟也稱為“橫向拉伸及縱向收縮”。In the present specification, a stretching machine having a plurality of clips that sandwich a film while moving between a pair of rails is used, and shrinkage in the film transport direction caused by shortening the distance between the clips is simultaneously performed on each rail. The step of stretching in a direction orthogonal to the film transport direction by the distance between the pair of rails that expand the above-described clip movement is also referred to as "lateral stretching and longitudinal contraction".

具體而言，本發明的聚酯膜的製造方法優選包括以下步驟：使用具有沿著設置於膜搬送路的兩側的一對軌道移動的夾子的拉幅機式拉伸裝置，邊通過上述的夾子夾持未拉伸的聚酯膜邊使其橫向拉伸或橫向拉伸及縱向收縮或縱向收縮。Specifically, the method for producing a polyester film of the present invention preferably includes the step of using a tenter type stretching device having a clip that moves along a pair of rails provided on both sides of the film conveying path, while passing through the above-described The clip holds the unstretched polyester film side transversely or transversely and longitudinally or longitudinally.

作為具有沿著設置於膜搬送路的兩側的一對軌道移動的夾子的拉幅機式拉伸裝置，沒有特別限制。一對軌道通常使用一對環形的軌道。另外，夾子與夾持構件含義相同。The tenter stretching device having the clip that moves along a pair of rails provided on both sides of the film conveying path is not particularly limited. A pair of tracks typically use a pair of annular tracks. In addition, the clip has the same meaning as the clamping member.

本發明的聚酯膜的製造方法將擠出後的膜進行橫向拉伸或橫向拉伸及縱向收縮或縱向收縮。橫向拉伸邊將未拉伸的聚酯膜沿著膜搬送路搬送，邊沿著與膜搬送方向正交的方向進行。縱向收縮沿著膜搬送方向進行。The method for producing a polyester film of the present invention performs transverse stretching or transverse stretching and longitudinal shrinkage or longitudinal shrinkage of the extruded film. The unstretched polyester film is conveyed along the film conveyance path while being stretched in the transverse direction, and is formed in a direction orthogonal to the film conveyance direction. The longitudinal contraction proceeds along the film transport direction.

通過進行拉伸，能夠較大地顯現出面內方向的延遲Re。特別是為了達成滿足後述的Re、Rth、Re/Rth的範圍的聚酯膜，至少進行橫向拉伸或橫向拉伸及縱向收縮或縱向收縮。在其後進行橫向或縱向拉伸的情況下，也可以增大縱向、橫向的拉伸倍率中的橫向拉伸的拉伸倍率而不平衡地進行拉伸。By performing stretching, the retardation Re in the in-plane direction can be largely exhibited. In particular, in order to achieve a polyester film satisfying the range of Re, Rth, and Re/Rth described later, at least transverse stretching, transverse stretching, longitudinal shrinkage, or longitudinal shrinkage are performed. In the case of stretching in the transverse direction or the longitudinal direction thereafter, it is also possible to increase the stretching ratio of the transverse stretching in the stretching ratio in the machine direction and the transverse direction without performing the stretching in a balanced manner.

首先，對式B1的左側的不等式進行說明， [數學式13]為 [數學式14] 0.8 First, the inequality on the left side of the equation B1 will be described, [Mathematical Formula 13] For [Math 14] 0.8

以上的情況下，若最終的拉伸中的各軌道上的夾子間的距離的最小值y_min 為滿足式B2的範圍，則通過膜不鬆弛地收縮至y_min 來抑制鬆弛傷痕的產生，同時平面性變得良好，能夠抑制搬送中（也優選後步驟中）的斷裂。In the above case, if the minimum value y _min of the distance between the clips on each of the tracks in the final stretching is in the range satisfying the formula B2, the film is prevented from contracting to y _min without slackening, thereby suppressing the occurrence of slack scars. The flatness is improved, and it is possible to suppress breakage during transportation (and preferably in the subsequent step).

接著，對式B1的右側的不等式進行說明，通過使 [數學式15]為 [數學式16] 1.3 Next, the inequality on the right side of the equation B1 will be described by making [Math 15] For [Math 16] 1.3

以下，在拉伸機內膜不會鬆弛，能夠抑制傷痕的產生。Hereinafter, the film inside the stretching machine does not slack, and the occurrence of scratches can be suppressed.

本發明的聚酯膜的製造方法滿足下述式B2。 [數學式17]･･･式B2The method for producing a polyester film of the present invention satisfies the following formula B2. [Math 17] ・・・式B2

式B2表示橫向拉伸及縱向收縮中的縱向收縮的倍率。式B2的範圍、即縱向收縮的倍率為0.4～0.9倍，優選為0.5～0.8倍，更優選為0.5～0.7倍。Formula B2 represents the magnification of the longitudinal shrinkage in the transverse stretching and the longitudinal shrinkage. The range of the formula B2, that is, the ratio of the longitudinal shrinkage is 0.4 to 0.9 times, preferably 0.5 to 0.8 times, and more preferably 0.5 to 0.7 times.

本發明的聚酯膜的製造方法滿足下述式B3。The method for producing a polyester film of the present invention satisfies the following formula B3.

[數學式18]･･･式B3[Math 18] ・・・式B3

式B3表示橫向拉伸及縱向收縮中的橫向拉伸的倍率。即，通過用夾子夾持膜的兩端，邊進行加熱邊將夾子間擴寬，能夠達成式B3。式B3的範圍、即橫向拉伸倍率為3～6.5倍，更優選為3.5～6倍，特別優選為4～5.5倍。Formula B3 represents the magnification of the transverse stretching in the transverse stretching and the longitudinal shrinkage. That is, by sandwiching both ends of the film with a clip, the gap between the clips is widened while heating, and Formula B3 can be achieved. The range of the formula B3, that is, the transverse stretching ratio is 3 to 6.5 times, more preferably 3.5 to 6 times, and particularly preferably 4 to 5.5 times.

橫向拉伸步驟中的拉伸溫度（拉伸平均溫度T1）優選為70℃以上且170℃以下，更優選為80℃以上且160℃以下，進一步優選為90℃以上且150℃以下。這裡所謂的拉伸溫度是指從拉伸開始到結束為止的平均溫度。The stretching temperature (stretching average temperature T1) in the transverse stretching step is preferably 70° C. or higher and 170° C. or lower, more preferably 80° C. or higher and 160° C. or lower, and still more preferably 90° C. or higher and 150° C. or lower. The stretching temperature referred to herein means the average temperature from the start to the end of the stretching.

在橫向拉伸步驟中的預熱、拉伸、熱定型、熱鬆弛、及冷卻中，作為將聚酯膜進行加熱、或冷卻的溫度控制方法，可列舉出對聚酯膜吹送溫風或冷風、或者使聚酯膜與能夠控制溫度的金屬板的表面接觸、或者經過金屬板的附近。In the preheating, stretching, heat setting, thermal relaxation, and cooling in the transverse stretching step, as a temperature control method for heating or cooling the polyester film, blowing of warm air or cold air to the polyester film is exemplified. Or, the polyester film is brought into contact with the surface of the metal plate capable of controlling temperature or passes through the vicinity of the metal plate.

＜熱定型、熱鬆弛＞<Heat setting, thermal relaxation>

本發明的聚酯膜的製造方法優選在同時在拉伸平均溫度T1下進行向膜搬送方向的收縮和上述的向與膜搬送方向正交的方向的拉伸後，包括在熱定型溫度T2≥T1+30℃下進行加熱的熱定型步驟。其中，T1及T2的單位為℃。In the method for producing a polyester film of the present invention, it is preferable to perform the shrinkage in the film transport direction at the stretching average temperature T1 and the above-described stretching in the direction orthogonal to the film transport direction, and the heat setting temperature T2 ≥ Heat setting step for heating at T1 + 30 °C. Among them, the unit of T1 and T2 is °C.

本發明的聚酯膜的製造方法優選在將上述的橫向拉伸或橫向拉伸及縱向收縮或縱向收縮的聚酯膜從上述的夾子釋放前，包括將上述的拉伸後的聚酯膜加熱至拉幅機內的最高溫度為止的熱定型步驟；和邊將上述的熱定型步驟後的聚酯膜加熱邊使上述的一對軌道間距離變窄的熱鬆弛步驟。The method for producing a polyester film of the present invention preferably comprises heating the above-mentioned stretched polyester film before releasing the above-mentioned transversely stretched or transversely stretched and longitudinally or longitudinally contracted polyester film from the above-mentioned clip. a heat setting step up to the highest temperature in the tenter; and a thermal relaxation step of narrowing the distance between the pair of tracks described above while heating the polyester film after the heat setting step described above.

在拉伸後，為了促進結晶化，優選進行稱為“熱定型”的熱處理。其通過在超過拉伸溫度的溫度下進行，能夠促進結晶化，提高膜的強度。After the stretching, in order to promote crystallization, it is preferred to carry out a heat treatment called "heat setting". By carrying out at a temperature exceeding the stretching temperature, crystallization can be promoted and the strength of the film can be improved.

在熱定型中，為了結晶化，進行體積收縮。In heat setting, volume shrinkage is performed for crystallization.

作為熱定型的方法，沿寬度方向平行地設置數條對拉伸部送出熱風的狹縫。可以通過使從該狹縫吹出的氣體的溫度比拉伸部高來達成。進而在本發明的聚酯膜的製造方法中，優選如後述那樣，將聚酯膜的寬度方向的端部利用加熱器進行輻射加熱。As a method of heat setting, a plurality of slits for sending hot air to the stretching portion are provided in parallel in the width direction. This can be achieved by making the temperature of the gas blown out from the slit higher than the stretched portion. Further, in the method for producing a polyester film of the present invention, it is preferred that the end portion in the width direction of the polyester film is radiantly heated by a heater as will be described later.

此外，在本發明的聚酯膜的製造方法中，還優選在將膜進行加熱的熱風吹出噴嘴的端部側的所期望的位置安裝1塊或多塊遮風板，減緩膜端部的冷卻，相對於將上述的橫向拉伸後的聚酯膜從上述的夾子釋放時的膜寬度方向中央部的膜面溫度，容易使膜寬度方向上距離夾子200mm的位置即膜端部的膜面溫度提高1～20℃。Further, in the method for producing a polyester film of the present invention, it is preferable to attach one or a plurality of windshields at a desired position on the end side of the hot air blowing nozzle for heating the film to slow the cooling of the film end portion. With respect to the film surface temperature at the center portion in the film width direction when the polyester film after the transverse stretching is released from the above-described clip, it is easy to make the film surface temperature of the film end portion 200 cm away from the clip in the film width direction. Increase by 1 to 20 °C.

此外，也可以在拉伸（部）出口附近設置熱源（IR加熱器、鹵素加熱器等），進行升溫。Further, a heat source (IR heater, halogen heater, or the like) may be provided in the vicinity of the extension (portion) outlet to raise the temperature.

熱定型溫度優選為T2≥T1+30℃，熱定型溫度T2更優選超過T1+50℃，熱定型溫度T2特別優選為T1+60℃以上。The heat setting temperature is preferably T2 ≥ T1 + 30 ° C, the heat setting temperature T2 is more preferably more than T1 + 50 ° C, and the heat setting temperature T2 is particularly preferably T1 + 60 ° C or more.

熱定型的優選的溫度優選為100℃以上且250℃以下，更優選為150℃以上且245℃以下。The preferred temperature for heat setting is preferably 100 ° C or more and 250 ° C or less, and more preferably 150 ° C or more and 245 ° C or less.

在熱定型時也可以進行縱向收縮。Longitudinal shrinkage is also possible during heat setting.

優選與熱處理同時進行收縮（也稱為鬆弛。使膜收縮），優選沿TD（橫向）、MD（縱向）中的至少一者進行。本發明的聚酯膜的製造方法優選邊進行向膜搬送方向的收縮邊進行熱定型。It is preferred to carry out shrinkage (also referred to as relaxation to shrink the film) simultaneously with the heat treatment, preferably in at least one of TD (transverse direction) and MD (longitudinal direction). The method for producing a polyester film of the present invention is preferably heat-set while performing shrinkage in the film transport direction.

這樣的鬆弛也可以通過例如在拉幅機中使用縮放儀狀的卡盤，縮短縮放儀的間隔，或者使夾子在電磁石上驅動，降低其速度來達成。Such slack can also be achieved, for example, by using a pantograph-like chuck in a tenter, shortening the spacing of the pantograph, or driving the clip on the electromagnet to reduce its speed.

縱向鬆弛在120℃以上且230以下、更優選在130℃以上且220℃以下、進一步優選在140℃以上且210℃以下進行，這從抑制擦傷的觀點出發是優選的。通過縱向鬆弛，還具有在寬度方向拉伸中使Re/Rth上升的效果。這是由於，通過在橫向拉伸中鬆弛縱向，促進橫配向而容易增大Re。關於鬆弛量，縱向鬆弛為1%以上且10%以下的鬆弛從抑制聚酯膜中擦傷的產生的觀點出發是優選的，更優選為2%以上且8%以下，進一步優選為3%以上且7%以下。若為該優選的範圍的下限值以上，則容易難以出現上述效果，難以產生擦傷。另一方面，若為該優選的範圍的上限值以下，則變得難以產生鬆弛，變得難以與拉伸機接觸，變得難以產生擦傷。The longitudinal relaxation is preferably 120 ° C or more and 230 or less, more preferably 130 ° C or more and 220 ° C or less, and still more preferably 140 ° C or more and 210 ° C or less, which is preferable from the viewpoint of suppressing abrasion. The longitudinal relaxation also has an effect of increasing Re/Rth during stretching in the width direction. This is because it is easy to increase Re by relaxing the longitudinal direction in the transverse stretching and promoting the transverse alignment. With respect to the amount of slack, the relaxation of the longitudinal relaxation of 1% or more and 10% or less is preferable from the viewpoint of suppressing the occurrence of scratches in the polyester film, more preferably 2% or more and 8% or less, and still more preferably 3% or more. 7% or less. If it is at least the lower limit of the preferred range, the above-described effects are less likely to occur, and scratching is less likely to occur. On the other hand, when it is at most the upper limit of the preferable range, it becomes difficult to cause slack, and it becomes difficult to contact with a stretching machine, and it becomes difficult to generate a scratch.

通過在熱定型時進行縱向收縮，可以使Re、Rth、Re/Rth比更加最適，能夠抑制虹斑的產生。By performing longitudinal shrinkage during heat setting, the ratios of Re, Rth, and Re/Rth can be made more optimal, and generation of rainbow spots can be suppressed.

橫向的鬆弛溫度優選為上述的熱定型溫度的範圍，可以是與熱定型相同的溫度，也可以高，也可以低。The transverse relaxation temperature is preferably in the range of the above-described heat setting temperature, and may be the same temperature as the heat setting, or may be high or low.

橫向鬆弛量也優選與縱向鬆弛量相同的範圍。橫向鬆弛可以通過縮短擴寬的夾子的寬度來達成。The amount of lateral relaxation is also preferably in the same range as the amount of longitudinal relaxation. Lateral relaxation can be achieved by shortening the width of the widened clip.

通過上述拉伸、熱定型，變得容易能夠達成本發明的聚酯膜的Re、Rth、Re/Rth。即，通過利用這些方法進行拉伸、熱定型，容易形成體現虹斑降低的效果的本發明的聚酯膜。By the above stretching and heat setting, it is easy to achieve Re, Rth, and Re/Rth of the polyester film of the present invention. That is, by performing stretching and heat setting by these methods, it is easy to form the polyester film of the present invention which exhibits the effect of reducing rainbow spots.

進而，本發明的聚酯膜的製造方法優選在進行上述的拉幅機內的上述的熱定型的區域及進行上述的熱鬆弛的區域中的至少一者中，將聚酯膜的寬度方向的端部利用加熱器進行輻射加熱。若進行所述輻射加熱，則所製作的聚酯膜的TD方向上的MD熱收縮率變得容易降低，MD熱收縮率的分佈變得容易變小，容易製造滿足已述的式（1）～（4）的膜。Further, in the method for producing a polyester film of the present invention, it is preferable that at least one of the heat-set region and the heat-relaxing region in the tenter described above are used in the width direction of the polyester film. The ends are heated by radiation using a heater. When the radiant heating is performed, the MD heat shrinkage ratio in the TD direction of the produced polyester film is easily lowered, and the distribution of the MD heat shrinkage rate is easily reduced, and it is easy to manufacture and satisfy the above-described formula (1). ~(4) film.

在熱鬆弛部中將膜的TD方向端部進行輻射加熱時，可以將熱定型部中的輻射加熱省略，也可以在熱定型部及熱鬆弛部這兩者中進行。When the TD direction end portion of the film is radiantly heated in the thermal relaxation portion, the radiant heating in the heat setting portion may be omitted, or may be performed in both the heat setting portion and the thermal relaxation portion.

聚酯膜的TD方向端部的加熱使用能夠輻射加熱的加熱器來進行，優選選擇性地將聚酯膜的TD方向的至少一個端部進行加熱。從抑制局部的MD熱收縮的觀點出發，優選將聚酯膜的TD方向的兩個端部進行加熱。另外，“選擇性加熱”不是對包含聚酯膜的端部的膜整體進行加熱，而是指將膜端部局部地進行加熱。The heating of the TD-direction end portion of the polyester film is performed using a radiant-heatable heater, and it is preferred to selectively heat at least one end portion of the polyester film in the TD direction. From the viewpoint of suppressing local MD heat shrinkage, it is preferred to heat both end portions of the polyester film in the TD direction. Further, "selective heating" does not mean heating the entire film including the end portion of the polyester film, but means heating the film end portion locally.

作為能夠輻射加熱的加熱器，可列舉出例如紅外線加熱器，特別優選使用陶瓷制的加熱器（陶瓷加熱器）。Examples of the radiant-heatable heater include an infrared heater, and a ceramic heater (ceramic heater) is particularly preferably used.

能夠輻射加熱的加熱器可以僅使用1個，也可以使用2個以上。The heater capable of radiant heating may be used alone or in combination of two or more.

聚酯膜的TD方向端部的加熱優選將聚酯膜表面與加熱器的最短距離設為10mm以上且300mm以下來進行。The heating of the TD-direction end portion of the polyester film is preferably carried out by setting the shortest distance between the surface of the polyester film and the heater to 10 mm or more and 300 mm or less.

聚酯膜表面與加熱器的最短距離為10mm以上，則難以因加熱器間距而產生溫度不均，若為300mm以下，則輻射熱容易充分傳遞至膜中。When the shortest distance between the surface of the polyester film and the heater is 10 mm or more, temperature unevenness is unlikely to occur due to the heater pitch, and if it is 300 mm or less, radiant heat is easily transmitted to the film.

加熱器表面與膜表面的最短距離優選為50mm以上且250mm以下，更優選為80mm以上且200mm以下。The shortest distance between the surface of the heater and the surface of the film is preferably 50 mm or more and 250 mm or less, and more preferably 80 mm or more and 200 mm or less.

除了膜表面與加熱器表面的距離以外，根據需要，優選進一步調整加熱器的表面溫度而對膜進行加熱。In addition to the distance between the surface of the film and the surface of the heater, it is preferred to further adjust the surface temperature of the heater to heat the film as needed.

陶瓷制加熱器中的至少1個的表面溫度優選為300℃以上且700℃以下。通過表面溫度為300℃以上，輻射熱容易充分傳遞至膜中，通過為700℃以下，能夠抑制膜的過加熱。The surface temperature of at least one of the ceramic heaters is preferably 300 ° C or more and 700 ° C or less. When the surface temperature is 300° C. or more, radiant heat is easily transmitted to the film sufficiently, and when it is 700° C. or less, overheating of the film can be suppressed.

陶瓷制加熱器的表面溫度更優選為400℃以上且650℃以下，進一步優選為450℃以上且650℃以下。The surface temperature of the ceramic heater is more preferably 400 ° C or more and 650 ° C or less, and still more preferably 450 ° C or more and 650 ° C or less.

陶瓷制加熱器優選被格子狀的金屬罩覆蓋。通過加熱器被格子狀的金屬罩覆蓋，能夠防止破裂的膜與加熱器碰撞，而加熱器破損。構成罩的金屬沒有特別限制，可列舉出例如SUS304等不銹鋼等。The ceramic heater is preferably covered by a lattice-shaped metal cover. By covering the heater with a lattice-shaped metal cover, it is possible to prevent the cracked film from colliding with the heater and the heater is broken. The metal constituting the cover is not particularly limited, and examples thereof include stainless steel such as SUS304.

此外，在輻射加熱時，優選將膜TD方向上的溫度不均縮窄至0.7℃以上且3.0℃以下的範圍，由此，能夠將膜寬度方向上的結晶化度的不均減輕至0.5%以上且3.0%以下的範圍。若這樣操作，則寬度方向上的鬆弛差減輕，可抑制傷痕的產生，並且能夠更加提高耐水解性。Further, in the case of radiant heating, it is preferable to narrow the temperature unevenness in the film TD direction to a range of 0.7 ° C or more and 3.0 ° C or less, whereby the unevenness of the degree of crystallization in the film width direction can be reduced to 0.5%. The above range is 3.0% or less. By doing so, the difference in slack in the width direction is reduced, the occurrence of scratches can be suppressed, and the hydrolysis resistance can be further improved.

聚酯膜的MD方向的長度分佈容易依賴於進行橫向拉伸的拉伸裝置的出口附近的冷卻的方式。通常，存在膜的MD方向的長度在快速冷卻的部位變長，在慢冷卻的部位變短的傾向。認為其基於下面的理由。認為膜通過冷卻進行收縮（熱膨脹的相反的現象），但若快速冷卻，則收縮的時間少，所以膜沒有充分收縮，結果是，MD方向的膜長變長。相反，認為若膜被慢冷卻，則由於充分收縮，所以MD方向的膜長變短。The length distribution of the polyester film in the MD direction is easily dependent on the manner of cooling in the vicinity of the exit of the stretching device that performs the transverse stretching. In general, there is a tendency that the length of the film in the MD direction becomes longer at the portion where the cooling is rapidly performed, and becomes shorter at the portion where the cooling is slow. It is considered to be based on the following reasons. It is considered that the film shrinks by cooling (the opposite phenomenon of thermal expansion), but if it is rapidly cooled, the shrinkage time is small, so the film does not shrink sufficiently, and as a result, the film length in the MD direction becomes long. On the contrary, it is considered that if the film is slowly cooled, the film length in the MD direction becomes short due to sufficient shrinkage.

拉伸裝置的夾持構件的溫度為100℃～150℃左右，若其與拉伸裝置的冷卻溫度（通常為常溫～100℃左右）相比則為比較高的溫度。因此，在拉伸裝置的冷卻部中，由於夾持構件的溫度高，相反膜端部的溫度變高，與膜中央部的冷卻狀況相比，膜端部存在被慢冷卻的傾向。由此，與膜中央部相比，膜端部的MD方向的膜長更容易變短。The temperature of the holding member of the stretching device is about 100 to 150 ° C, and is relatively high when compared with the cooling temperature of the stretching device (generally from about room temperature to about 100 ° C). Therefore, in the cooling portion of the stretching device, since the temperature of the sandwiching member is high, the temperature of the film end portion is increased, and the film end portion tends to be slowly cooled as compared with the cooling state at the center portion of the film. Thereby, the film length in the MD direction of the film end portion is more likely to be shorter than the central portion of the film.

在以往的聚酯膜中，由於產生上述的MD方向的膜長度分佈（圓弧），所以膜中央部與膜端部相比，MD熱收縮率小，存在成為MD方向的膜長大的膜的傾向。In the conventional polyester film, since the film length distribution (arc) in the MD direction described above is generated, the MD heat shrinkage rate is smaller than the film end portion, and the film having a large film length in the MD direction is present. tendency.

那樣的話，膜中央部由於未加熱前的原來的MD方向的膜長長，並且在加熱搬送時更難以收縮，所以變得更長，產生鬆弛並出現傷痕、皺褶，在後步驟中膜容易斷裂。In this case, since the film center portion is long in the original MD direction before heating, and it is more difficult to shrink during heat transfer, it becomes longer, and slacks and scratches and wrinkles occur, and the film is easy in the subsequent step. fracture.

＜膜的回收、切割、卷曲＞<Recycling, cutting, and curling of film>

上述横向拉伸及從夾子的釋放步驟結束後，將膜根據需要進行修剪、切割、去厚加工，為了回收而卷曲。After the lateral stretching and the releasing step from the clip are completed, the film is trimmed, cut, and thickened as needed, and curled for recycling.

本發明的聚酯膜的製造方法中，從夾子釋放後的膜寬度為0.8～6m從有效確保膜製品寬度、且裝置尺寸不會變得過大的觀點出發是優選的，更優選為1～5m，特別優選為1～4m。需要精度的光學用膜通常以低於3m進行制膜，但在本發明中，優選以上述那樣的寬度進行制膜。In the method for producing a polyester film of the present invention, the film width after release from the clip is preferably 0.8 to 6 m from the viewpoint of effectively ensuring the width of the film product and the device size is not excessively increased, and more preferably 1 to 5 m. It is particularly preferably 1 to 4 m. The film for optics requiring precision is usually formed at a film thickness of less than 3 m. However, in the present invention, it is preferable to form a film having the above-described width.

此外，也可以將經寬幅制膜的膜切割成優選2條以上且6條以下、更優選2條以上且5條以下、進一步優選3條以上且4條以下後，進行卷曲。Further, the film formed by the wide film formation may be preferably diced into two or more and six or less, more preferably two or more and five or less, more preferably three or more and four or less.

另外，在將膜的端部以任意的寬度進行修剪的情況下或在制膜後切割成任意的條數的情況下，修剪或切割後的膜寬度相當於本發明的聚酯膜的膜寬度。Further, in the case where the end portion of the film is trimmed with an arbitrary width or cut into an arbitrary number after film formation, the film width after trimming or cutting corresponds to the film width of the polyester film of the present invention. .

此外，優選在切割後，對兩端進行去厚加工（賦予滾花）。Further, it is preferable to perform a thickening process (giving knurling) on both ends after the dicing.

卷曲優選卷曲1000m以上且10000m以下到直徑為70mm以上且600mm以下的卷芯上。膜的每截面積的卷曲張力優選為3～30kgf/cm² ，更優選為5～25kgf/cm² ，進一步優選為7～20kgf/cm² 。此外，經卷曲的膜的厚度與日本專利4962661號的[0049]相同。此外，也優選在卷曲前貼合掩膜。The curl is preferably curled on a core of 1000 m or more and 10000 m or less to a diameter of 70 mm or more and 600 mm or less. Each cross-sectional area of the crimped film tension is preferably 3 ~ 30kgf / cm ^2, more preferably 5 ~ 25kgf / cm ^2, more preferably 7 ~ 20kgf / cm ^2. Further, the thickness of the curled film is the same as [0049] of Japanese Patent No. 4962661. Further, it is also preferred to apply a mask before crimping.

[偏振板][Polarizing Plate]

本發明的聚酯膜可以用作偏振板保護膜。The polyester film of the present invention can be used as a polarizing plate protective film.

本發明的偏振板包含具有偏光性能的偏振片、和本發明的聚酯膜。本發明的偏振板除了本發明的聚酯膜以外，還可以進一步包含纖維素醯化物膜等偏振板保護膜。The polarizing plate of the present invention comprises a polarizing plate having polarizing properties, and a polyester film of the present invention. The polarizing plate of the present invention may further contain a polarizing plate protective film such as a cellulose oxime film in addition to the polyester film of the present invention.

偏振板的形狀不僅包含切斷成能夠直接組裝到液晶顯示裝置中的大小的膜片的形態的偏振板，還包含通過連續生產製作成長條狀並以卷狀卷曲的形態（例如卷長為2500m以上或3900m以上的形態）的偏振板。為了製成大畫面液晶顯示裝置用，偏振板的寬度優選設為1470mm以上。The shape of the polarizing plate includes not only a polarizing plate cut into a form of a diaphragm which can be directly assembled into a liquid crystal display device, but also a form in which a strip is formed by continuous production and rolled in a roll shape (for example, a roll length of 2500 m) A polarizing plate of the above or a form of 3900 m or more. In order to produce a large-screen liquid crystal display device, the width of the polarizing plate is preferably set to 1470 mm or more.

如WO2011/162198號公報的[0025]中記載的那樣將由PVA構成的偏振片與本發明的聚酯膜貼合，可以製備偏振板。此時，優選使上述易膠粘層與PVA接觸。進而，也優選如WO2011/162198號公報的[0024]中記載的那樣與具有延遲的保護膜組合。A polarizing plate comprising a PVA and a polyester film of the present invention are bonded together as described in [0025] of WO2011/162198. At this time, it is preferred to bring the above-mentioned easy-adhesive layer into contact with PVA. Further, it is also preferable to combine with a protective film having a retardation as described in [0024] of WO2011/162198.

[圖像顯示裝置][Image display device]

本發明的聚酯膜可以用於圖像顯示裝置，可以將包含本發明的聚酯膜的偏振板用作圖像顯示裝置的偏振板。The polyester film of the present invention can be used for an image display device, and a polarizing plate comprising the polyester film of the present invention can be used as a polarizing plate of an image display device.

本發明的圖像顯示裝置具備本發明的聚酯膜、或本發明的偏振板。The image display device of the present invention comprises the polyester film of the present invention or the polarizing plate of the present invention.

作為上述的圖像顯示裝置，可列舉出液晶顯示器（LCD）、等離子體顯示器（PDP）、電致發光顯示器（OELD或IELD）、場致發射顯示器（FED）、觸摸面板、電子紙等。這些圖像顯示裝置優選在圖像顯示面板的顯示畫面側具備本發明的偏振板。Examples of the image display device described above include a liquid crystal display (LCD), a plasma display (PDP), an electroluminescence display (OELD or IELD), a field emission display (FED), a touch panel, and electronic paper. These image display devices preferably include the polarizing plate of the present invention on the display screen side of the image display panel.

作為將偏振板與液晶顯示裝置等圖像顯示裝置貼合的方法，可以使用公知的方法。此外，也可以使用輥對面板制法，在提高生產率、成品率的方面是優選的。輥對面板制法記載於日本特開2011-48381號公報、日本特開2009-175653號公報、日本專利4628488號公報、日本專利4729647號公報、WO2012/014602號、WO2012/014571號等中，但並不限定於它們。As a method of bonding a polarizing plate to an image display device such as a liquid crystal display device, a known method can be used. Further, a roll-to-face plate method can also be used, which is preferable in terms of improving productivity and yield. The roll-to-panel method is described in Japanese Laid-Open Patent Publication No. 2011-48381, JP-A-2009-175653, Japanese Patent No. 4628488, Japanese Patent No. 4729647, WO2012/014602, WO2012/014571, and the like. Not limited to them.

在圖像顯示裝置中，光源優選使用具有連續的發光光譜的光源。In the image display device, the light source preferably uses a light source having a continuous luminescence spectrum.

這是由於，如WO2011/162198號公報的[0019]～[0020]記載的那樣變得容易消除虹斑。This is because it is easy to eliminate rainbow spots as described in [0019] to [0020] of WO2011/162198.

作為圖像顯示裝置中使用的光源，使用WO2011/162198號公報的[0013]記載的光源。另一方面，WO2011/162198號公報的[0014]～[0015]記載的光源不是連續光源，不優選。As the light source used in the image display device, the light source described in [0013] of WO2011/162198 is used. On the other hand, the light source described in [0014] to [0015] of WO2011/162198 is not a continuous light source, and is not preferable.

圖像顯示裝置為LCD的情況下，液晶顯示裝置（LCD）可以使用WO2011/162198號公報的[0011]～[0012]中記載的構成。In the case where the image display device is an LCD, the liquid crystal display device (LCD) can use the configuration described in [0011] to [0012] of WO2011/162198.

使用本發明的聚酯膜和/或本發明的偏振板的液晶顯示裝置優選為使用了具有連續的發光光譜的白色光源的液晶顯示裝置，由此，與使用不連續（亮線）光源的情況相比，能夠有效降低虹斑。其是引用日本專利4888853號的[0015]～[0027]（US2012/0229732號公報的[0029]～[0041]）中記載的理由，由於與該理由同樣的理由，這些公報中記載的內容被納入本說明書中。The liquid crystal display device using the polyester film of the present invention and/or the polarizing plate of the present invention is preferably a liquid crystal display device using a white light source having a continuous light emission spectrum, thereby using a discontinuous (bright line) light source. In comparison, it can effectively reduce rainbow spots. The reason described in [0015] to [0027] of Japanese Patent No. 4888853 ([0029] to [0041] of US2012/0229732) is the same as the reason, and the contents described in these publications are Into this manual.

液晶顯示裝置優選為具備本發明的偏振板、和液晶顯示元件的液晶顯示裝置。其中，代表性的液晶顯示元件是具備在上下基板間封入有液晶的液晶單元，並通過施加電壓使液晶的配向狀態發生變化而進行圖像的顯示的液晶面板，此外，對於等離子體顯示器面板、CRT顯示器、有機EL顯示器等公知的各種顯示器，也可以適用本發明的偏振板。這樣，在將具有延遲高的本發明的聚酯膜的偏振板適用於液晶顯示元件的情況下，能夠防止液晶顯示元件的翹曲。The liquid crystal display device is preferably a liquid crystal display device including the polarizing plate of the present invention and a liquid crystal display element. In the liquid crystal display device, a liquid crystal panel including a liquid crystal cell in which liquid crystal is sealed between the upper and lower substrates, and a liquid crystal alignment state is changed by applying a voltage, and an image is displayed, and the plasma display panel and the plasma display panel are provided. A polarizing plate of the present invention can also be applied to various known displays such as a CRT display and an organic EL display. As described above, when a polarizing plate having a polyester film of the present invention having a high retardation is applied to a liquid crystal display element, warpage of the liquid crystal display element can be prevented.

其中，虹狀的色斑起因於延遲高的聚酯膜的延遲和背光源的發光光譜。以往，作為液晶顯示裝置的背光源，使用冷陰極管或熱陰極管等螢光管。冷陰極管或熱陰極管等螢光燈的分光分佈顯示具有多個峰的發光光譜，這些不連續的發光光譜相合而得到白色的光源。光透射過延遲高的膜的情況下，根據波長而顯示不同的透射光強度。因此，若背光源為不連續的發光光譜，則僅特定的波長被強透射而產生虹狀的色斑。Among them, the rainbow-like color spots are caused by the retardation of the polyester film having a high retardation and the luminescence spectrum of the backlight. Conventionally, as a backlight of a liquid crystal display device, a fluorescent tube such as a cold cathode tube or a hot cathode tube is used. The spectral distribution of a fluorescent lamp such as a cold cathode tube or a hot cathode tube shows an emission spectrum having a plurality of peaks, and these discontinuous emission spectra are combined to obtain a white light source. When light is transmitted through a film having a high retardation, different transmitted light intensities are displayed depending on the wavelength. Therefore, if the backlight is a discontinuous luminescence spectrum, only a specific wavelength is strongly transmitted to produce a rainbow-like color smear.

圖像顯示裝置為液晶顯示裝置的情況下，優選包含背光源、和配置於2片偏振板之間的液晶單元作為構成構件。此外，也可以適當具有除它們以外的其他構成、例如濾色片、透鏡膜、擴散片材、防反射膜等。When the image display device is a liquid crystal display device, it is preferable to include a backlight and a liquid crystal cell disposed between the two polarizing plates as a constituent member. Further, other configurations than these, such as a color filter, a lens film, a diffusion sheet, an antireflection film, and the like, may be appropriately provided.

作為背光源的構成，可以是以導光板或反射板等作為構成構件的側光方式，也可以是直下型方式，本發明中，作為液晶顯示裝置的背光源使用白色發光二極體（白色LED）從改善虹斑的觀點出發是優選的。在本發明中，白色LED是指通過螢光體方式、即將使用了化合物半導體的發出藍色光、或紫外光的發光二極體與螢光體組合而發出白色的元件。作為螢光體，有釔･鋁･石榴石系的黃色螢光體、鋱･鋁･石榴石系的黃色螢光體等。其中，由將使用了化合物半導體的藍色發光二極體與釔･鋁･石榴石系黃色螢光體組合而成的發光元件構成的白色發光二極體由於具有連續且寬幅的發光光譜，並且發光效率也優異，所以作為本發明的圖像顯示裝置的背光源是合適的。另外，這裡所謂發光光譜是連續的是指至少在可見光的區域中不存在光的強度達到零的波長。此外，由於通過本發明可以廣泛利用耗電量小的白色LED，因此還能夠發揮節能化的效果。The configuration of the backlight may be a side light type using a light guide plate or a reflection plate as a constituent member, or may be a direct type. In the present invention, a white light emitting diode (white LED) is used as a backlight of the liquid crystal display device. It is preferable from the viewpoint of improving rainbow spots. In the present invention, the white LED refers to an element which emits white by a combination of a phosphor, a light-emitting diode that emits blue light or ultraviolet light using a compound semiconductor, and a phosphor. Examples of the phosphor include a yellow phosphor of bismuth, aluminum, and garnet, and a yellow phosphor of bismuth, aluminum, and garnet. Among them, a white light-emitting diode composed of a light-emitting element in which a blue light-emitting diode using a compound semiconductor and a yttrium aluminum-garnet yellow phosphor are combined has a continuous and wide light-emitting spectrum. Further, since the luminous efficiency is also excellent, it is suitable as a backlight of the image display device of the present invention. In addition, the term "luminescence spectrum" as used herein refers to a wavelength at which the intensity of light does not reach zero at least in the region of visible light. Further, since the white LED having a small power consumption can be widely used by the present invention, it is possible to exert an energy saving effect.

作為通過上述方式可抑制虹狀的色斑的產生的機制，在國際公開WO2011/162198號中有記載，該公報的內容被納入本發明中。The mechanism for suppressing the generation of rainbow-like color spots by the above-described method is described in International Publication No. WO2011/162198, the contents of which are incorporated herein.

此外，本發明中的圖像顯示裝置優選包含作為背光源的至少具有藍色、綠色和紅色的發光峰的光源單元、和兩面具有偏振板的液晶單元。Further, the image display device of the present invention preferably includes, as a backlight, a light source unit having at least blue, green, and red luminescence peaks, and a liquid crystal cell having polarizing plates on both sides.

光源單元的發光光譜至少具有藍色、綠色和紅色的發光峰，綠色、及紅色的發光峰的半峰全寬為20nm以上，在波長460nm～520nm之間至少具有一個極小值L1，在波長520nm～560nm之間至少具有一個極大值L2，在波長560nm～620nm之間至少具有一個極小值L3，L1、及L3的值優選低於L2的35%。The light-emitting spectrum of the light source unit has at least blue, green, and red light-emitting peaks, and the green and red light-emitting peaks have a full width at half maximum of 20 nm or more, and have at least one minimum value L1 between wavelengths of 460 nm and 520 nm at a wavelength of 520 nm. There is at least one maximum value L2 between ～560 nm, and at least one minimum value L3 between wavelengths 560 nm and 620 nm, and the values of L1 and L3 are preferably lower than 35% of L2.

綠色、及紅色的發光峰的半峰全寬優選為20nm以上且60nm以下，光源單元的綠色的發光峰、及紅色的發光峰中，半值寬度小的發光峰的半值寬度W優選為50nm以下，最優選為20nm以上且40nm以下。若半峰全寬小，則能夠提高液晶顯示裝置的色再現性，所以優選。此外，若半峰全寬為20nm以上，則通過使用具有5000nm以上的Re的第1保護膜，能夠使其不產生虹斑，所以優選。The full width at half maximum of the green and red luminescence peaks is preferably 20 nm or more and 60 nm or less. Among the green luminescence peaks of the light source unit and the red luminescence peaks, the half value width W of the luminescence peak having a small half value width is preferably 50 nm. Hereinafter, it is most preferably 20 nm or more and 40 nm or less. When the full width at half maximum is small, the color reproducibility of the liquid crystal display device can be improved, which is preferable. Further, when the full width at half maximum is 20 nm or more, it is preferable to use a first protective film having Re of 5000 nm or more to prevent generation of rainbow spots.

L1、及L3的值更優選低於L2的20%，最優選低於10%。若L1、及L3的值小於L2的值，則藍色、綠色、及紅色的發光分離，能夠提高液晶顯示裝置的色再現性，所以優選。The values of L1 and L3 are more preferably less than 20% of L2, and most preferably less than 10%. When the values of L1 and L3 are smaller than the value of L2, the light emission of blue, green, and red is separated, and the color reproducibility of the liquid crystal display device can be improved, which is preferable.

光源單元也可以具有藍色發光二極體、綠色發光二極體、及紅色發光二極體，但從降低成本的觀點出發，優選至少具有藍色發光二極體、或紫外線發光二極體、和通過被來自藍色發光二極體或紫外線發光二極體的光激發能夠發光的螢光體。在使用藍色發光二極體的情況下，優選具有發光成綠色的螢光體、及發光成紅色的螢光體，在使用紫外線發光二極體的情況下，優選具有發光成藍色的螢光體、發光成綠色的螢光體、及發光成紅色的螢光體。The light source unit may have a blue light emitting diode, a green light emitting diode, and a red light emitting diode. However, from the viewpoint of cost reduction, it is preferable to have at least a blue light emitting diode or an ultraviolet light emitting diode. And a phosphor that can emit light by excitation of light from a blue light-emitting diode or an ultraviolet light-emitting diode. When a blue light-emitting diode is used, it is preferable to have a phosphor that emits green light and a phosphor that emits red light. When an ultraviolet light-emitting diode is used, it is preferable to have a light-emitting blue light. A light body, a phosphor that emits green light, and a phosphor that emits red light.

上述的螢光體也可以被封入藍色發光二極體、或紫外線發光二極體的內部，但為了防止因熱而導致的螢光體的劣化，優選將螢光體封入玻璃管的內部，按照藍色發光二極體、或紫外線發光二極體的發光照射到的方式配置，或者將包含螢光體的膜配置於光源單元的內部。The above-described phosphor may be enclosed in a blue light-emitting diode or an ultraviolet light-emitting diode. However, in order to prevent deterioration of the phosphor due to heat, it is preferable to encapsulate the phosphor inside the glass tube. The light is emitted in such a manner as to emit light from the blue light emitting diode or the ultraviolet light emitting diode, or the film including the phosphor is disposed inside the light source unit.

螢光體優選至少1個包含納米尺寸的半導體粒子即量子點。量子點螢光體由於能夠減小發光峰的半峰全寬，可以提高液晶顯示裝置的色再現性，所以優選。The phosphor preferably has at least one quantum dot containing semiconductor particles of a nanometer size. The quantum dot phosphor is preferable because it can reduce the full width at half maximum of the luminescence peak and improve the color reproducibility of the liquid crystal display device.

此外，通常包含量子點的光源由於發光效率高，所以與使用了白色LED或冷陰極管（CCFL）的背光源單元相比，能夠抑制來自背光源單元的發熱。因此，將液晶顯示裝置在高溫高濕環境中保存後，可以抑制點亮時的溫度上升，可以進一步降低液晶單元的翹曲、及顯示不均。Further, since the light source including the quantum dots generally has high luminous efficiency, it is possible to suppress heat generation from the backlight unit as compared with a backlight unit using a white LED or a cold cathode tube (CCFL). Therefore, after the liquid crystal display device is stored in a high-temperature and high-humidity environment, temperature rise during lighting can be suppressed, and warpage of the liquid crystal cell and display unevenness can be further reduced.

另外，光源單元的發光光譜可以使用TOPCON TECHNOHOUSE CORPORATION制分光放射計“SR-3”進行測定。Further, the light emission spectrum of the light source unit can be measured using a spectroradiometer "SR-3" manufactured by TOPCON TECHNOHOUSE CORPORATION.

對一般的冷陰極管（CCFL）的發光光譜進行說明。藍色、綠色、及紅色具有尖的發光峰，因此，藍色、綠色、及紅色的發光分離，通常使用了CCFL的液晶顯示裝置的色再現性比使用了白色LED的液晶顯示器優異。另一方面，由於綠色、及紅色的發光峰的半峰全寬小至約2nm以下，所以作為第1保護膜使用具有高的Re的膜的情況下，視覺辨認到虹斑。The luminescence spectrum of a general cold cathode tube (CCFL) will be described. Blue, green, and red have sharp illuminating peaks. Therefore, blue, green, and red illuminating are separated, and liquid crystal display devices using CCFLs generally have better color reproducibility than liquid crystal displays using white LEDs. On the other hand, since the full width at half maximum of the green and red luminescence peaks is as small as about 2 nm or less, when a film having a high Re is used as the first protective film, rainbow spots are visually recognized.

對一般的白色LED的發光光譜進行說明。白色LED通常在藍色發光二極體的內部封入發光成黃色、或綠色和紅色的有機螢光體而製作。該情況下，綠色、及紅色的發光峰的半峰全寬達到20nm以上，因此，通常在使用了白色LED的液晶顯示裝置中，在作為第1保護膜使用具有高的Re的膜的情況下，虹斑得到抑制。另一方面，由於在波長460nm～520nm之間、及波長560nm～620nm之間不具有極小值、或極小值比波長520nm～560nm之間的極大值L2大，所以藍色、綠色、及紅色的發光的分離變得不充分，色再現性差。The luminescence spectrum of a general white LED will be described. The white LED is usually produced by enclosing an organic phosphor that emits yellow, or green and red, inside the blue light-emitting diode. In this case, the full width at half maximum of the green and red luminescence peaks is 20 nm or more. Therefore, in the liquid crystal display device using the white LED, when a film having a high Re is used as the first protective film, The rainbow spot is suppressed. On the other hand, since there is no minimum value between the wavelengths of 460 nm to 520 nm and the wavelengths of 560 nm to 620 nm, or the minimum value L2 between the wavelengths of 520 nm and 560 nm is large, blue, green, and red are used. The separation of the light is insufficient, and the color reproducibility is poor.

對使用了量子點螢光體的光源的發光光譜進行說明。使用了量子點螢光體的光源由於通常綠色、及紅色的發光峰的半峰全寬為20nm以上，在波長460nm～520nm之間至少具有一個極小值L1，在波長520nm～560nm之間至少具有一個極大值L2，在波長560nm～620nm之間至少具有一個極小值L3，L1、及L3的值低於L2的35%，所以可以作為本發明的圖像顯示裝置的光源單元適當使用。The luminescence spectrum of a light source using a quantum dot phosphor will be described. A light source using a quantum dot phosphor has a full width at half maximum of 20 nm or more, and has at least one minimum value L1 between wavelengths of 460 nm and 520 nm, and at least between wavelengths of 520 nm and 560 nm. The maximum value L2 has at least one minimum value L3 between the wavelengths of 560 nm and 620 nm, and the values of L1 and L3 are lower than 35% of L2. Therefore, it can be suitably used as the light source unit of the image display device of the present invention.

本發明的圖像顯示裝置為液晶顯示裝置的情況下，本發明的偏振板的配置沒有特別限制。本發明的偏振板優選作為液晶顯示裝置中的視覺辨認側用的偏振板來使用。In the case where the image display device of the present invention is a liquid crystal display device, the arrangement of the polarizing plate of the present invention is not particularly limited. The polarizing plate of the present invention is preferably used as a polarizing plate for a visual recognition side in a liquid crystal display device.

面內方向的延遲高的本發明的聚酯膜的配置沒有特別限定，但在配置有配置於入射光側（光源側）的偏振板、液晶單元和配置於出射光側（視覺辨認側）的偏振板的液晶顯示裝置的情況下，配置於入射光側的偏振板的入射光側的偏振板保護膜、或配置於出射光側的偏振板的射出光側的偏振板保護膜優選為面內方向的延遲高的本發明的聚酯膜。特別優選的方式為使配置於出射光側的偏振板的射出光側的偏振板保護膜為面內方向的延遲高的本發明的聚酯膜的方式。在上述以外的位置配置面內方向的延遲高的聚酯膜的情況下，有時會使液晶單元的偏光特性發生變化。由於優選在不需要偏光特性的部位使用面內方向的延遲高的本發明的聚酯膜，所以優選作為這樣的特定的位置的偏振板的保護膜來使用。The arrangement of the polyester film of the present invention having a high retardation in the in-plane direction is not particularly limited, but a polarizing plate disposed on the incident light side (light source side), a liquid crystal cell, and a side disposed on the outgoing light side (visual identification side) are disposed. In the case of the liquid crystal display device of the polarizing plate, the polarizing plate protective film disposed on the incident light side of the polarizing plate on the incident light side or the polarizing plate protective film disposed on the light emitting side of the polarizing plate on the outgoing light side is preferably in-plane. The polyester film of the present invention having a high retardation in the direction. In a particularly preferred embodiment, the polarizing plate protective film disposed on the light-emitting side of the polarizing plate on the light-emitting side is a polyester film of the present invention having a high retardation in the in-plane direction. When a polyester film having a high retardation in the in-plane direction is disposed at a position other than the above, the polarization characteristics of the liquid crystal cell may be changed. It is preferable to use the polyester film of the present invention having a high retardation in the in-plane direction at a portion where the polarization characteristics are not required, and therefore it is preferably used as a protective film of a polarizing plate at such a specific position.

液晶顯示裝置的液晶單元優選具有液晶層和設置於該液晶層的兩側的兩塊玻璃基板。玻璃基板的厚度優選為0.5mm以下，更優選為0.4mm以下，特別優選為0.3mm以下。The liquid crystal cell of the liquid crystal display device preferably has a liquid crystal layer and two glass substrates disposed on both sides of the liquid crystal layer. The thickness of the glass substrate is preferably 0.5 mm or less, more preferably 0.4 mm or less, and particularly preferably 0.3 mm or less.

液晶顯示裝置的液晶單元優選為IPS模式、VA模式、FFS模式。The liquid crystal cell of the liquid crystal display device is preferably an IPS mode, a VA mode, or an FFS mode.

[硬塗膜][hard coating film]

本發明的聚酯膜可以用於硬塗膜。硬塗膜具有硬塗層和作為透明膜的本發明的聚酯膜。The polyester film of the present invention can be used for a hard coat film. The hard coat film has a hard coat layer and a polyester film of the present invention as a transparent film.

硬塗層可以通過濕式塗布法、乾式塗布法（真空成膜）中的任一種來形成，優選通過生產率優異的濕式塗布法來形成。The hard coat layer can be formed by any of a wet coating method and a dry coating method (vacuum film formation), and is preferably formed by a wet coating method excellent in productivity.

作為硬塗層，可以使用例如日本特開2013-45045號公報、日本特開2013-43352號公報、日本特開2012-232459號公報、日本特開2012-128157號公報、日本特開2011-131409號公報、日本特開2011-131404號公報、日本特開2011-126162號公報、日本特開2011-75705號公報、日本特開2009-286981號公報、日本特開2009-263567號公報、日本特開2009-75248號公報、日本特開2007-164206號公報、日本特開2006-96811號公報、日本特開2004-75970號公報、日本特開2002-156505號公報、日本特開2001-272503號公報、WO12/018087、WO12/098967、WO12/086659、WO11/105594中記載的硬塗層。For the hard coat layer, for example, JP-A-2013-45045, JP-A-2013-43352, JP-A-2012-232459, JP-A-2012-128157, and JP-A-2011-131409 Japanese Laid-Open Patent Publication No. 2011-131, pp., JP-A-2011-126162, JP-A-2011-75705, JP-A-2009-286981, JP-A-2009-263567, and JP-A-2009-263567 Japanese Laid-Open Patent Publication No. 2009-75248, JP-A-2007-164206, JP-A-2006-96811, JP-A-2004-75970, JP-A-2002-156505, and JP-A-2001-272503 The hard coat layer described in the publications, WO 12/018087, WO 12/098967, WO 12/086659, and WO 11/105594.

本發明的聚酯膜可以用於觸摸面板用感測器膜。觸摸面板用感測器膜在聚酯膜上層疊有硬塗層、透明導電層。The polyester film of the present invention can be used for a sensor film for a touch panel. The sensor film for a touch panel has a hard coat layer and a transparent conductive layer laminated on the polyester film.

作為形成透明導電層的一般的方式，有濺射法、真空蒸鍍法、離子鍍法等PVD法、或CVD法、塗敷法、印刷法等。另外，作為透明導電層的形成材料，沒有特別限制，可列舉出例如銦･錫複合氧化物（ITO）、錫氧化物、銅、銀、鋁、鎳、鉻等，也可以是不同的形成材料重疊而形成。此外，透明導電層有時在形成透明導電層之前，也設置用於提高透明性或光學特性等的底塗層。為了進一步提高粘附性，有時也在上述底塗層與聚酯膜之間設置由單一的金屬元素或2種以上的金屬元素的合金構成的金屬層。在金屬層中，優選使用選自由矽、鈦、錫及鋅組成的組中的金屬。As a general form of forming a transparent conductive layer, there are a PVD method such as a sputtering method, a vacuum deposition method, or an ion plating method, or a CVD method, a coating method, a printing method, or the like. In addition, the material for forming the transparent conductive layer is not particularly limited, and examples thereof include indium/tin composite oxide (ITO), tin oxide, copper, silver, aluminum, nickel, chromium, and the like, and may be different forming materials. Formed by overlapping. Further, the transparent conductive layer may be provided with an undercoat layer for improving transparency or optical characteristics, etc., before forming the transparent conductive layer. In order to further improve the adhesion, a metal layer composed of a single metal element or an alloy of two or more metal elements may be provided between the undercoat layer and the polyester film. Among the metal layers, a metal selected from the group consisting of ruthenium, titanium, tin, and zinc is preferably used.

本發明的聚酯膜可以用於防止玻璃飛散膜。防止玻璃飛散膜在聚酯膜上層疊有硬塗層、粘合劑層。The polyester film of the present invention can be used to prevent a glass scattering film. The glass scattering film is prevented from laminating a hard coat layer or an adhesive layer on the polyester film.

粘合劑層可以通過濕式塗布法、乾式塗布法中的任一種來形成。為了形成粘合劑層，可以使用溶劑系丙烯酸聚合物或溶劑系丙烯酸糖漿、無溶劑系丙烯酸糖漿、無溶劑氨基甲酸酯丙烯酸酯等丙烯酸系粘合劑組成物。The pressure-sensitive adhesive layer can be formed by any of a wet coating method and a dry coating method. In order to form the pressure-sensitive adhesive layer, an acrylic pressure-sensitive adhesive composition such as a solvent-based acrylic polymer or a solvent-based acrylic syrup, a solvent-free acrylic syrup, or a solventless urethane acrylate can be used.

[觸摸面板][Touch Panel]

本發明的聚酯膜可以在觸摸面板中使用。此外，在觸摸面板中可以使用上述的硬塗膜、上述的觸摸面板用感測器膜、及上述的防止玻璃飛散膜中的至少一者。The polyester film of the present invention can be used in a touch panel. Further, at least one of the above-described hard coat film, the above-described sensor film for a touch panel, and the above-described glass scattering preventing film can be used for the touch panel.

本發明的觸摸面板沒有特別限制，可以根據目的適當選擇，可列舉出例如表面型靜電容量方式觸摸面板、投影型靜電容量方式觸摸面板、電阻膜式觸摸面板等。另外，觸摸面板是指包含所謂的觸摸感測器及觸控板的元件。觸摸面板中的觸摸面板感測器電極部的層構成可以是將2片透明電極貼合的貼合方式、在1塊基板的兩面具備透明電極的方式、單面跳線或通孔方式或單面層疊方式中的任一種。此外，關於投影型靜電容量方式觸摸面板，與DC驅動相比優選AC驅動，更優選對電極的電壓施加時間少的驅動方式。The touch panel of the present invention is not particularly limited, and may be appropriately selected according to the purpose, and examples thereof include a surface-type electrostatic capacitance type touch panel, a projection type electrostatic capacitance type touch panel, and a resistive film type touch panel. In addition, the touch panel refers to an element including a so-called touch sensor and a touch panel. The layer configuration of the touch panel sensor electrode portion in the touch panel may be a bonding method in which two transparent electrodes are bonded, a transparent electrode is provided on both surfaces of one substrate, a single-sided jumper or a through hole method, or a single Any of the face stacking methods. Further, the projection type electrostatic capacitance type touch panel is preferably AC driven as compared with DC driving, and more preferably a driving method in which the voltage application time of the electrode is small.

實施例Example

以下列舉出實施例和比較例，對本發明的特徵進一步進行具體說明。以下的實施例中所示的材料、使用量、比例、處理內容、處理步驟等只要不脫離本發明的主旨，可以進行適當變更。因此，本發明的範圍並不受以下所示的具體例子的限定性解釋。The features of the present invention will be further specifically described below by way of examples and comparative examples. The materials, the amounts, the ratios, the processing contents, the processing steps, and the like shown in the following examples can be appropriately changed without departing from the gist of the invention. Therefore, the scope of the invention is not limited by the specific examples shown below.

另外，只要沒有特別說明，則“份”為品質基準。In addition, unless otherwise indicated, "part" is a quality standard.

[實施例1][Example 1]

＜原料聚酯的合成＞<Synthesis of raw material polyester>

（原料聚酯1）(Materials 1)

如以下所示的那樣，採用使對苯二甲酸及乙二醇直接反應並將水蒸餾除去，進行酯化後，在減壓下進行縮聚的直接酯化法，利用連續聚合裝置得到原料聚酯1（Sb催化劑系PET）。As shown below, a direct esterification method in which terephthalic acid and ethylene glycol are directly reacted and water is distilled off, esterification is carried out, and polycondensation is carried out under reduced pressure, and a raw material polyester is obtained by a continuous polymerization apparatus. 1 (Sb catalyst system PET).

（1）酯化反應(1) Esterification reaction

在第一酯化反應槽中，將高純度對苯二甲酸4.7噸和乙二醇1.8噸用90分鐘混合而形成漿料，以3800kg/h的流量連續地供給到第一酯化反應槽中。進一步連續地供給三氧化銻的乙二醇溶液，在反應槽內溫度250℃、攪拌下，以平均滯留時間約4.3小時進行反應。此時，三氧化銻按照Sb添加量以元素換算值計達到150ppm的方式連續地添加。In the first esterification reaction tank, 4.7 tons of high-purity terephthalic acid and 1.8 tons of ethylene glycol were mixed for 90 minutes to form a slurry, and continuously supplied to the first esterification reaction tank at a flow rate of 3800 kg/h. . Further, an ethylene glycol solution of antimony trioxide was continuously supplied, and the reaction was carried out with an average residence time of about 4.3 hours while stirring at a temperature of 250 ° C in the reaction vessel. At this time, antimony trioxide was continuously added so that the amount of Sb added was 150 ppm in terms of element conversion value.

將該反應產物移送到第二酯化反應槽中，在攪拌下、反應槽內溫度250℃下，以平均滯留時間計反應1.2小時。對第二酯化反應槽，按照Mg添加量及P添加量以元素換算值計分別達到65ppm、35ppm的方式連續地供給醋酸鎂的乙二醇溶液和磷酸三甲酯的乙二醇溶液。The reaction product was transferred to a second esterification reaction tank, and the reaction was carried out for 1.2 hours in an average residence time under stirring at a temperature of 250 ° C in the reaction vessel. In the second esterification reaction tank, an ethylene glycol solution of magnesium acetate and an ethylene glycol solution of trimethyl phosphate were continuously supplied in such a manner that the amount of Mg added and the amount of P added were 65 ppm and 35 ppm, respectively, in terms of elemental conversion values.

（2）縮聚反應(2) polycondensation reaction

將上述得到的酯化反應產物連續地供給到第一縮聚反應槽中，在攪拌下、反應溫度270℃、反應槽內壓力20torr（2.67×10^-3 MPa）下，以平均滯留時間約1.8小時使其縮聚。The esterification reaction product obtained above was continuously supplied to the first polycondensation reaction tank, and the average residence time was about 1.8 hours under stirring at a reaction temperature of 270 ° C and a pressure of 20 torr (2.67 × 10 ^-3 MPa) in the reaction vessel. Make it polycondensate.

進而，移送到第二縮聚反應槽中，在該反應槽中，在攪拌下、反應槽內溫度276℃、反應槽內壓力5torr（6.67×10^-4 MPa）下、滯留時間約1.2小時的條件下使其反應（縮聚）。Furthermore, it is transferred to the second polycondensation reaction tank, and the conditions of the residence time are about 1.25 ° C in the reaction vessel, the pressure in the reaction vessel is 5 torr (6.67 × 10 ^-4 MPa), and the residence time is about 1.2 hours. Let it react (polycondensation).

接著，進一步移送到第三縮聚反應槽中，在該反應槽中，在反應槽內溫度278℃、反應槽內壓力1.5torr（2.0×10^-4 MPa）、滯留時間1.5小時的條件下使其反應（縮聚），得到反應產物（聚對苯二甲酸乙二醇酯（PET））。Then, it was further transferred to a third polycondensation reaction tank, and in the reaction vessel, the temperature in the reaction vessel was 278 ° C, the pressure in the reaction vessel was 1.5 torr (2.0 × 10 ^-4 MPa), and the residence time was 1.5 hours. The reaction (polycondensation) gives the reaction product (polyethylene terephthalate (PET)).

接著，將所得到的反應產物以股線狀噴出到冷水中，立即切斷而製作聚酯的顆粒＜截面：長徑約為4mm、短徑約為2mm、長度：約為3mm＞。Next, the obtained reaction product was sprayed into cold water in a strand shape, and immediately cut to prepare a pellet of polyester <section: long diameter: about 4 mm, short diameter of about 2 mm, and length: about 3 mm>.

所得到的聚合物為IV=0.63（以後，簡稱為PET1）。將該聚合物作為原料聚酯1。The obtained polymer was IV = 0.63 (hereinafter, abbreviated as PET1). This polymer was used as the raw material polyester 1.

＜聚酯膜的製造＞<Manufacture of polyester film>

膜成形步驟Film forming step

將原料聚酯1（PET1）乾燥至含水率為20ppm以下後，投入到直徑為50mm的單軸混煉擠出機1的料斗1中。原料聚酯1在300℃下熔融，通過下述擠出條件，介由齒輪泵、篩檢程式（孔徑為20μm），從模擠出。The raw material polyester 1 (PET1) was dried to a water content of 20 ppm or less, and then placed in a hopper 1 of a uniaxial kneading extruder 1 having a diameter of 50 mm. The raw material polyester 1 was melted at 300 ° C, and extruded from a die through a gear pump and a screening program (pore diameter: 20 μm) by the following extrusion conditions.

關於熔融樹脂的擠出條件，將壓力變動設為1%，將熔融樹脂的溫度分佈設為2%，將熔融樹脂從模擠出。具體而言，將背壓相對於擠出機的滾筒內平均壓力加壓1%，在擠出機的配管溫度相對於擠出機的滾筒內平均溫度高2%的溫度下進行加熱。Regarding the extrusion conditions of the molten resin, the pressure fluctuation was set to 1%, the temperature distribution of the molten resin was set to 2%, and the molten resin was extruded from the die. Specifically, the back pressure was pressurized by 1% with respect to the average pressure in the drum of the extruder, and heating was performed at a temperature at which the pipe temperature of the extruder was 2% higher than the average temperature in the drum of the extruder.

從模擠出的熔融樹脂擠出到溫度設定為25℃的冷卻流延鼓上，使用靜電施加法使其與冷卻流延鼓粘附。使用與冷卻流延鼓相對配置的剝取輥進行剝離，得到未拉伸聚酯膜1。The molten resin extruded from the die was extruded onto a cooling casting drum set to a temperature of 25 ° C, and adhered to the cooling casting drum by an electrostatic application method. Peeling was performed using a peeling roll disposed opposite to the cooling casting drum to obtain an unstretched polyester film 1.

所得到的未拉伸聚酯膜1特性粘度IV=0.62，長度方向的折射率為1.573，結晶化度為0.2%。The obtained unstretched polyester film 1 had an intrinsic viscosity of 0.4.62, a refractive index in the longitudinal direction of 1.573, and a degree of crystallization of 0.2%.

關於IV，將未拉伸聚酯膜1溶解到1,1,2,2-四氯乙烷/苯酚（=2/3[品質比]）混合溶劑中，由在該混合溶劑中的25℃下的溶液粘度求出。Regarding IV, the unstretched polyester film 1 was dissolved in a mixed solvent of 1,1,2,2-tetrachloroethane/phenol (=2/3 [quality ratio]) from 25 ° C in the mixed solvent. The viscosity of the solution below was determined.

未拉伸聚酯膜的折射率通過以下的方法測定。The refractive index of the unstretched polyester film was measured by the following method.

使用兩片偏振板，求出未拉伸聚酯膜的配向軸方向，按照配向軸方向正交的方式切出4cm×2cm的長方形，作為測定用樣品。對該樣品，通過阿貝折射率計（ATAGO CO.,LTD.制、NAR-4T、測定波長589nm）求出正交的雙軸的折射率（Nx，Ny）、及厚度方向的折射率（Nz）。Using two polarizing plates, the direction of the alignment axis of the unstretched polyester film was determined, and a rectangle of 4 cm × 2 cm was cut out so as to be orthogonal to the direction of the alignment axis, and used as a sample for measurement. The sample was subjected to an Abbe refractometer (manufactured by ATAGO CO., LTD., NAR-4T, measurement wavelength: 589 nm) to obtain an orthogonal biaxial refractive index (Nx, Ny) and a refractive index in the thickness direction ( Nz).

未拉伸聚酯膜的結晶化度通過以下的方法測定。The degree of crystallization of the unstretched polyester film was measured by the following method.

關於結晶化度，可以由膜的密度算出。即，可以使用膜的密度X（g/cm³ ）、結晶化度為0%時的密度1.335g/cm³ 、結晶化度為100%時的密度1.501g/cm³ ，由下述計算式匯出結晶化度（%）。The degree of crystallization can be calculated from the density of the film. That is, using a film density X (g / cm ^3), crystallinity of 0% of the density 1.335g / cm ^3, a crystallinity of 100% of the density 1.501g / cm ^3, is calculated by the following formula The degree of crystallization (%) is remitted.

橫向拉伸步驟Lateral stretching step

將未拉伸聚酯膜1導入具有多個邊夾持膜邊在一對軌道間移動的夾子的拉幅機拉伸機，邊將未拉伸聚酯膜1的端部用夾子夾持，邊用下述的方法、條件進行橫向拉伸。The unstretched polyester film 1 is introduced into a tenter stretching machine having a plurality of clips that sandwich the film while moving between the pair of rails, and the end portion of the unstretched polyester film 1 is held by a clip. The transverse stretching was carried out by the following methods and conditions.

（預熱部）(preheating section)

將預熱溫度設為75℃，加熱至能夠拉伸的溫度。The preheating temperature was set to 75 ° C and heated to a temperature at which stretching was possible.

（拉伸部）(stretching part)

將預熱後的未拉伸聚酯膜1沿寬度方向在下述的條件以及拉伸中的各位置處的聚酯膜的寬度x’及拉伸中的各位置處的各軌道上的夾子間的距離y’按照在拉伸中總是成立下述式B1的關係的方式設定，使用拉幅機同時進行橫向拉伸及縱向收縮。The pre-heated unstretched polyester film 1 is in the width direction under the following conditions and the width x' of the polyester film at each position in the stretching and the inter-clip on each track at each position in the stretching The distance y' is set so as to always establish the relationship of the following formula B1 in the stretching, and the transverse stretching and the longitudinal contraction are simultaneously performed using a tenter.

＜條件＞･拉伸機的入口的寬度x：900mm ･拉伸機的入口處的各軌道上的夾子間的距離y：150mm ･橫向拉伸及縱向收縮溫度（橫向拉伸及縱向收縮中的拉伸平均溫度T1）：75℃ ･拉伸中的聚酯膜的最大寬度x_max ：4680mm ･橫向拉伸倍率（x_max /x）：5.2倍･拉伸中的聚酯膜的最大寬度為x_max /2時的x’：2340mm ･x’=x_max /2（=2340mm）時的 [數學式19]：0.62 ･拉伸中的各軌道上的夾子間的距離的最小值y_min ：67.5mm ･縱向拉伸倍率（：縱向收縮倍率；y_min /y）：0.45倍･x’=x_max /2（=2340mm）時的y’：89mm ･x’=x_max /2（=2340mm）時的y’/y：0.6倍 [數學式20]･･･式B1<Conditions> ・The width of the entrance of the stretching machine x: 900 mm ・The distance between the clips on the respective rails at the entrance of the stretching machine is y: 150 mm ・The transverse stretching and the longitudinal shrinkage temperature (in the transverse stretching and the longitudinal contraction) Stretching average temperature T1): 75 °C ・Maximum width of polyester film during stretching x _max : 4680 mm ・Transverse stretching ratio (x _max /x): 5.2 times • The maximum width of the polyester film during stretching is x _max / x at 2 ': 2340mm · x' = [ equation 19] at x _max / 2 (= 2340mm) : 0.62 ・The minimum value of the distance between the clips on each track in the stretching y _min : 67.5 _mm・The longitudinal stretching ratio (: longitudinal shrinkage ratio; y _min /y _): 0.45 times × x' = x _max /2 y': 89mm when (=2340mm) ・y'/y when x'=x _max /2 (=2340mm): 0.6 times [Math 20] ・・・式B1

（熱定型部）(heat setting section)

接著，對於膜使來自上下方向的熱風從熱風吹出噴嘴吹到膜上，邊將聚酯膜的膜面溫度控制在下述範圍，邊進行熱定型處理。Then, the hot air from the vertical direction is blown onto the film from the hot air blowing nozzle, and the heat setting treatment is performed while controlling the film surface temperature of the polyester film to the following range.

＜條件＞･夾子間距離收縮率（=熱定型區域出口處的各軌道上的夾子間的距離/熱定型區域入口處的各軌道上的夾子間的距離）：1.0倍（沒有收縮）･最高到達膜面溫度（熱定型溫度T2）：167℃ ･熱定型時間：15秒<Conditions> ・The distance between the clips is reduced (= the distance between the clips on the respective rails at the exit of the heat-set area/the distance between the clips on the respective rails at the entrance of the heat-set area): 1.0 times (no shrinkage) ・Highest Membrane surface temperature (heat setting temperature T2): 167 °C ・Heat setting time: 15 seconds

進而，在實施例1中，對膜寬度方向（TD方向）的兩端部、具體而言相對於膜全寬距離兩端每寬度方向的20%的合計40%的部分由在膜成形步驟中與流延鼓接觸的流延面側，通過陶瓷制的紅外線加熱器（加熱器表面溫度：650℃）進行輻射加熱。此時，加熱器與聚酯膜的距離設為170mm。Further, in the first embodiment, the portion at the both ends in the film width direction (TD direction), specifically, 40% of the total width in the width direction of both ends of the film full width is 40% in the film forming step. Radiation heating was performed by a ceramic infrared heater (heater surface temperature: 650 ° C) on the casting surface side in contact with the casting drum. At this time, the distance between the heater and the polyester film was set to 170 mm.

（冷卻部）(cooling section)

接著，不進行熱鬆弛，將熱定型後的聚酯膜在膜的TD方向中央部的膜面溫度（A）達到80℃、在膜寬度方向上距離夾子200mm的位置即膜的TD方向端部的膜面溫度（B）達到88℃的冷卻溫度下冷卻。另外，膜中央部和端部的膜面溫度通過在將膜冷卻的吹出噴嘴的端部側的所期望的位置安裝1塊或多塊遮風板，減緩膜端部的冷卻來控制。Then, without performing thermal relaxation, the film surface temperature (A) of the heat-set polyester film in the center portion of the film in the TD direction is 80° C., and the position in the film width direction is 200 mm from the clip, that is, the end portion of the film in the TD direction. The film surface temperature (B) was cooled to a cooling temperature of 88 °C. Further, the film surface temperature at the central portion and the end portion of the film is controlled by attaching one or a plurality of windshields at a desired position on the end side of the blowing nozzle that cools the film to slow the cooling of the film end portion.

冷卻溫度是指冷卻部中的膜膜面溫度，從上下的方向吹95℃的冷風，與上述熱定型及熱鬆弛中的對端部的輻射加熱並用，能夠賦予上述（B）-（A）的溫度差。此外，將（B）-（A）的值記載於下述表1中。The cooling temperature is the film surface temperature in the cooling portion, and the cold air of 95 ° C is blown from the upper and lower directions, and is used in combination with the radiant heating at the opposite end in the heat setting and thermal relaxation, and the above (B)-(A) can be imparted. The temperature difference. Further, the values of (B) to (A) are described in Table 1 below.

在其他的實施例及比較例中，冷卻溫度也設為與夾子釋放膜時的膜膜面溫度相同的值。In the other examples and comparative examples, the cooling temperature was also set to the same value as the film surface temperature at the time of the clip release film.

（膜的釋放）(release of membrane)

將冷卻後的膜從拉幅機的夾子上釋放。夾子釋放膜時的膜的TD方向中央部的膜面溫度（A）為80℃，在膜寬度方向上距離夾子200mm的位置即膜的TD方向端部的膜面溫度（B）為88℃。The cooled film is released from the clip of the tenter. The film surface temperature (A) at the center portion in the TD direction of the film when the film was released was 80 ° C, and the film surface temperature (B) at the end portion of the film in the TD direction in the film width direction at a position of 200 mm from the clip was 88 ° C.

夾子釋放膜時的膜的TD方向中央部的膜面溫度（A）通過放射溫度計（林電工制、型號：RT61-2、以放射率0.95使用）來測定。The film surface temperature (A) of the center portion of the film in the TD direction when the film was released from the film was measured by a radiation thermometer (manufactured by Lin Biao, model: RT61-2, used at an emissivity of 0.95).

夾子釋放膜時的在膜寬度方向上距離夾子200mm的位置即膜的TD方向端部的膜面溫度（B）通過放射溫度計（林電工制、型號：RT61-2、以放射率0.95使用）來測定。When the film is released from the film, the film surface temperature (B) at the end of the film in the TD direction in the film width direction is the radiation thermometer (Model: RT61-2, used at an emissivity of 0.95). Determination.

（膜的回收）(recycling of membrane)

在冷卻及膜從夾子上的釋放之後，將聚酯膜的兩端每20cm進行修剪。修剪後的膜寬度為3m。之後，在兩端以寬度10mm進行擠出加工（滾花）後，以張力18kg/m將10000m的長度的膜卷曲成卷形態。After cooling and release of the film from the clip, both ends of the polyester film were trimmed every 20 cm. The trimmed film has a width of 3 m. Thereafter, after extrusion processing (knurling) at a width of 10 mm at both ends, a film having a length of 10000 m was crimped into a roll form at a tension of 18 kg/m.

如以上那樣操作，製造了以卷形態捲繞的厚度為10μm的實施例1的聚酯膜。As described above, the polyester film of Example 1 having a thickness of 10 μm wound in a roll form was produced.

[實施例2～24、比較例1～8][Examples 2 to 24 and Comparative Examples 1 to 8]

除了將實施例1中聚酯膜的製造條件如下述表1中記載的那樣進行變更以外，與實施例1同樣地操作，製造了實施例2～24、比較例1～8的聚酯膜。The polyester films of Examples 2 to 24 and Comparative Examples 1 to 8 were produced in the same manner as in Example 1 except that the production conditions of the polyester film of Example 1 were changed as described in Table 1 below.

另外，橫向拉伸步驟的各製造條件及熱定型時的夾子間距離收縮率通過變更拉幅機的設定來控制。另外，在比較例5中，將拉幅機設定為在拉伸中總是滿足數學式21的條件， [數學式21] Further, the respective manufacturing conditions of the transverse stretching step and the distance between the clips during the heat setting are controlled by changing the setting of the tenter. Further, in Comparative Example 5, the tenter was set to always satisfy the condition of Mathematical Formula 21 in stretching, [Math 21]

在比較例6中，將拉幅機設定為在拉伸中總是滿足數學式22的條件。 [數學式22] In Comparative Example 6, the tenter was set to always satisfy the condition of Mathematical Formula 22 in stretching. [Math 22]

實施例11、12、14、16、22、24及比較例8中的熱定型時的最高到達膜面溫度T2通過變更陶瓷制的紅外線加熱器的表面溫度來控制。The highest reaching film surface temperature T2 at the time of heat setting in Examples 11, 12, 14, 16, 22, 24 and Comparative Example 8 was controlled by changing the surface temperature of the ceramic infrared heater.

實施例2～24、比較例1～8的聚酯膜的膜厚僅通過使用與實施例1相同的未拉伸聚酯膜1，並將聚酯膜的製造條件如下述表1中記載的那樣進行變更就能夠控制在下述表2中記載的範圍。The film thickness of the polyester films of Examples 2 to 24 and Comparative Examples 1 to 8 was only the same as that of the unstretched polyester film 1 of Example 1, and the production conditions of the polyester film were as described in Table 1 below. By changing this, it is possible to control the range described in Table 2 below.

[實施例25][Example 25]

（原料聚酯2）(raw material polyester 2)

將乾燥後的紫外線吸收劑（2,2’-（1,4-亞苯基）雙（4H-3,1-苯並噁嗪-4-酮））10品質份、PET1（IV=0.63）90品質份混合，使用混煉擠出機，與PET1的製作同樣地進行顆粒化，得到含有紫外線吸收劑的原料聚酯2（以後，簡稱為PET2）。The dried UV absorber (2,2'-(1,4-phenylene)bis(4H-3,1-benzoxazin-4-one)) 10 parts by mass, PET1 (IV=0.63) 90 parts by mass were mixed, and granulated in the same manner as in the production of PET1 using a kneading extruder to obtain a raw material polyester 2 (hereinafter, abbreviated as PET 2) containing an ultraviolet absorber.

膜成形步驟Film forming step

將原料聚酯1（PET1）90品質份和含有紫外線吸收劑的原料聚酯2（PET2）10品質份乾燥至含水率為20ppm以下後，投入到直徑為50mm的單軸混煉擠出機1的料斗1中，在擠出機1中，在300℃下熔融。通過下述擠出條件，介由齒輪泵、篩檢程式（孔徑為20μm），從模擠出。90 parts by mass of the raw material polyester 1 (PET1) and 10 parts by mass of the raw material polyester 2 (PET2) containing the ultraviolet absorber were dried to a water content of 20 ppm or less, and then charged into a uniaxial kneading extruder 1 having a diameter of 50 mm. In the hopper 1, it was melted at 300 ° C in the extruder 1. The extrusion was carried out from a die through a gear pump and a screening program (pore size: 20 μm) by the following extrusion conditions.

從模擠出的熔融樹脂擠出到溫度設定為25℃的冷卻流延鼓上，使用靜電施加法使其與冷卻流延鼓粘附。使用與冷卻流延鼓相對配置的剝取輥進行剝離，得到未拉伸聚酯膜2。The molten resin extruded from the die was extruded onto a cooling casting drum set to a temperature of 25 ° C, and adhered to the cooling casting drum by an electrostatic application method. Peeling was performed using a peeling roll disposed opposite to the cooling casting drum to obtain an unstretched polyester film 2.

所得到的未拉伸聚酯膜2特性粘度IV=0.61，長度方向的折射率為1.574，結晶化度為0.1%。The obtained unstretched polyester film 2 had an intrinsic viscosity IV = 0.61, a refractive index in the longitudinal direction of 1.574, and a degree of crystallization of 0.1%.

將所得到的未拉伸聚酯膜2在與實施例15相同的條件下進行橫向拉伸，製造了厚度為65μm的實施例25的聚酯膜。The obtained unstretched polyester film 2 was transversely stretched under the same conditions as in Example 15 to produce a polyester film of Example 25 having a thickness of 65 μm.

[膜物性][membrane property]

＜膜厚度的測定＞<Measurement of film thickness>

所得到的各實施例及比較例的聚酯膜的厚度如以下那樣求出。The thickness of the polyester film of each of the obtained Examples and Comparative Examples was determined as follows.

對於各實施例及比較例的聚酯膜，使用接觸式膜厚測定計（ANRITSU公司制），在縱向拉伸的方向（長度方向）上對整個0.5m以等間隔取樣50點，進一步在膜寬度方向（與長度方向正交的方向）上對膜全寬以等間隔（沿寬度方向50等分）取樣50點後，測定這100點的厚度。求出這100點的平均的厚度，作為聚酯膜的厚度。將結果示於下述表2中。For the polyester film of each of the examples and the comparative examples, a contact type film thickness meter (manufactured by ANRITSU Co., Ltd.) was used to sample 50 points at equal intervals over the entire 0.5 m direction in the longitudinal direction (longitudinal direction), and further on the film. In the width direction (direction orthogonal to the longitudinal direction), the film was sampled at equal intervals (equal division in the width direction of 50) by 50 points, and the thickness of the 100 points was measured. The average thickness of these 100 points was determined as the thickness of the polyester film. The results are shown in Table 2 below.

＜Re、Rth、Re/Rth＞<Re, Rth, Re/Rth>

對於各實施例及比較例的膜，通過日本特開2012-256057號公報的[0054]～[0055]中記載的方法測定Re及Rth，將Re、Rth和Re/Rth的值記載於表2中。For the films of the respective examples and the comparative examples, Re and Rth were measured by the methods described in [0054] to [0055] of JP-A-2012-256057, and the values of Re, Rth, and Re/Rth are described in Table 2. in.

＜寬度方向上的MD熱收縮率及寬度方向上的MD熱收縮率不均＞<MD thermal shrinkage rate in the width direction and MD thermal shrinkage rate unevenness in the width direction>

將如上述那樣操作而得到的膜F裁切，製作了膜F的MD方向的達到膜長（L=26m）的一半的位置處的TD方向的兩端部（從膜端部沿寬度方向到10～40mm為止的30mm的部分）和TD方向中央部的3種試樣片M（將膜寬度方向的中心線作為試樣片的中心的30mm的部分）。另外，3種試樣片M製成TD方向為30mm、MD方向為120mm的大小。The film F obtained as described above was cut, and both ends of the film F in the TD direction at a position halfway up to the film length (L=26 m) in the MD direction were produced (from the film end to the width direction) Three kinds of sample pieces M in the center portion of the TD direction and a center line in the center in the TD direction (the portion in the center in the film width direction is a portion of 30 mm in the center of the sample piece). Further, the three kinds of sample pieces M were made to have a size of 30 mm in the TD direction and 120 mm in the MD direction.

對於3種試樣片M，按照在MD方向上達到100mm的間隔的方式，畫2根基準線，在無張力下在150℃的加熱烘箱中放置30分鐘。在該放置之後，將3種試樣片M冷卻至室溫，測定2根基準線的間隔，將該值設為A（單位；mm）。將由所測定的A及“100×（100-A）/100”的式算出的數值作為MD熱收縮率。For the three kinds of sample pieces M, two reference lines were drawn in such a manner as to reach an interval of 100 mm in the MD direction, and left in a heating oven at 150 ° C for 30 minutes under no tension. After the placement, the three kinds of sample pieces M were cooled to room temperature, and the interval between the two reference lines was measured, and the value was set to A (unit: mm). The numerical value calculated from the measured A and the formula of "100 × (100 - A) / 100" was taken as the MD heat shrinkage rate.

將測定在膜F中位於TD方向端部的試樣片M而得到的MD熱收縮率數值大的設為S_S1 ，將數值小的設為S_S2 。此外，將測定在膜F中位於TD方向的中央部的試樣片M而得到的MD熱收縮率設為S_CT 。The sample having the sample M obtained at the end in the TD direction of the film F and having a large value of the MD heat shrinkage rate is referred to as S _S1 , and the small value is referred to as S _S2 . Further, the film F is located in the measured TD direction central portion of the specimen M MD thermal shrinkage rate is obtained to S _CT.

另外，S_S1 表示膜寬度方向的端部中的與膜寬度方向正交的方向的熱收縮率（150℃、30分鐘）大的一側的聚酯膜的與膜寬度方向正交的方向的熱收縮率[%]，S_S2 表示膜寬度方向的端部中的與膜寬度方向正交的方向的熱收縮率（150℃、30分鐘）小的一側的聚酯膜的與膜寬度方向正交的方向的熱收縮率[%]。S_CT 表示膜寬度方向的膜中央部中的聚酯膜的與膜寬度方向正交的方向的熱收縮率（150℃、30分鐘）[%]。In addition, S _S1 indicates a direction in which the heat shrinkage ratio (150° C., 30 minutes) of the polyester film in the direction orthogonal to the film width direction in the film width direction is orthogonal to the film width direction. The heat shrinkage ratio [%], S _S2 represents the direction of the film width of the polyester film on the side where the heat shrinkage ratio (150 ° C, 30 minutes) in the direction orthogonal to the film width direction in the end portion in the film width direction is small. The heat shrinkage rate [%] in the orthogonal direction. S _CT indicates a heat shrinkage ratio (150 ° C, 30 minutes) [%] in a direction perpendicular to the film width direction of the polyester film in the film center portion in the film width direction.

（寬度方向上的MD熱收縮率）(MD thermal shrinkage in the width direction)

將3點的MD熱收縮率S_S1 、S_S2 及S_CT 的平均值作為寬度方向上的MD熱收縮率。將結果示於下述表2中。The average value of the MD heat shrinkage rates S _S1 , S _{S2 ,} and S _CT at three points was taken as the MD heat shrinkage ratio in the width direction. The results are shown in Table 2 below.

（寬度方向上的MD熱收縮率不均）(The MD heat shrinkage rate in the width direction is uneven)

將上述中得到的3點的MD熱收縮率S_S1 、S_S2 及S_CT 的最大值與最小值之差除以3點的MD熱收縮率S_S1 、S_S2 及S_CT 的平均值，求出以百分率表示的數值作為MD方向的熱收縮率不均（變動比例）。將结果示於下述表2中。The difference between the maximum value and the minimum value of the three-point MD thermal shrinkage rates S _S1 , S _S2 and S _CT obtained in the above is divided by the average values of the MD thermal shrinkage rates S _S1 , S _S2 and S _CT at three points. The numerical value expressed as a percentage is used as the heat shrinkage rate unevenness (variation ratio) in the MD direction. The results are shown in Table 2 below.

＜平面性＞<planarity>

拉伸後，自利用卷曲裝置卷曲的卷卷好起15分鐘以內，將卷的最外表層的部分（外卷部分、卷直徑為600mm）的膜切出成500mm見方。After the stretching, the film of the outermost layer portion (the outer coil portion and the coil diameter of 600 mm) of the outer surface layer of the roll was cut into a 500 mm square from the coil which was curled by the crimping device for 15 minutes.

將切出的膜置於平面上，在溫度為25℃、相對濕度為60%的條件下測定距離平面最高的部分的高度。The cut film was placed on a flat surface, and the height of the portion closest to the plane was measured under the conditions of a temperature of 25 ° C and a relative humidity of 60%.

將結果記載於下述表2中。The results are shown in Table 2 below.

[膜評估][membrane evaluation]

＜傷痕評估＞<Scar assessment>

通過目視試驗及Olympus Corporation制光學顯微鏡評估所製造的聚酯膜表面的傷痕。對長度方向500mm、全寬進行目視檢查，對發現的傷痕用光學顯微鏡測定長度。此外，關於傷痕的個數，算出每1m² 的平均值。The surface of the produced polyester film was evaluated for damage by a visual test and an optical microscope manufactured by Olympus Corporation. The length was 500 mm and the full width was visually inspected, and the length of the found scar was measured with an optical microscope. Further, the average value per 1 m ² was calculated for the number of the scars.

評估基準如下所述。 A：長度為1mm以上的傷痕低於10個/m² 。 B：長度為1mm以上的傷痕為10個/m² 以上且低於20個/m² 。 C：長度為1mm以上的傷痕為20個/m² 以上。The evaluation criteria are as follows. A: The flaw having a length of 1 mm or more is less than 10 / m ² . B: The number of scratches having a length of 1 mm or more is 10 pieces/m ² or more and less than 20 pieces/m ² . C: The number of scratches having a length of 1 mm or more is 20 pieces/m ² or more.

將結果示於下述表2中。The results are shown in Table 2 below.

[步驟適應性的評估][Steps for adaptive assessment]

＜搬送適應性＞<Transportability>

將按照以下的基準評估的結果記載於下述表1中。 A：卷曲長度為1000m以上，且在拉伸後的搬送中能夠不引起局部的裂紋･斷裂地搬送。 B：卷曲長度為1000m以內且在拉伸後的搬送中局部的裂紋或斷裂低於3處。 C：卷曲長度為1000m以內且在拉伸後的搬送中局部的裂紋或斷裂為3處以上。 D：卷曲長度為100m以內且產生裂紋･斷裂。The results of the evaluation based on the following criteria are described in Table 1 below. A: The crimp length is 1000 m or more, and it can be conveyed without causing local cracks or breakage during conveyance after stretching. B: The crimp length is 1000 m or less and the local crack or fracture is less than 3 in the conveyance after stretching. C: The crack length or the fracture was within 1000 m and the local crack or break during the conveyance after stretching was three or more. D: The crimp length is within 100 m and cracks and breaks occur.

將結果示於下述表2中。The results are shown in Table 2 below.

[偏振板及液晶顯示裝置的製作和液晶顯示裝置的虹斑的評估][Production of Polarizing Plate and Liquid Crystal Display Device and Evaluation of Rainbow Spot of Liquid Crystal Display Device]

使用各實施例及比較例的聚酯膜，製作各實施例及比較例的偏振板以及各實施例及比較例的液晶顯示裝置，進行評估。The polarizing plates of the respective examples and comparative examples and the liquid crystal display devices of the respective examples and comparative examples were produced and evaluated using the polyester films of the respective examples and comparative examples.

按照日本特開2011-59488號公報的[0225]，製備了包含PVA的偏振片。A polarizing plate containing PVA was prepared in accordance with [0225] of JP-A-2011-59488.

將下述纖維素醯化物膜根據日本專利4438270號的[0275]（US2007/0178252的[0393]、這些公報中記載的內容被納入本說明書中）浸漬到鹼水溶液中進行皂化處理。The cellulose oxime film described below is immersed in an aqueous alkali solution by saponification treatment according to [0275] of Japanese Patent No. 4,438,270 ([0393] of US2007/0178252, the contents of these publications being incorporated herein.

與日本專利4731143號的[0199]～[0202]（US2008/0158483的[0412]～[0416]、這些公報中記載的內容被納入本說明書中）同樣地操作，製備了纖維素醯化物膜。A cellulose oxime film was prepared in the same manner as in [0199] to [0202] of Japanese Patent No. 4,731, 141, [0412] to [0416] of US 2008/0158483, and the contents described in these publications are incorporated herein.

在各實施例及比較例的聚酯膜與經皂化處理的纖維素醯化物之間，夾持上述偏振片，在偏振片/聚酯間、纖維素醯化物/偏振片間上塗布PVA水溶液（完全皂化型PVA5%水溶液），將它們用夾持輥壓接而貼合後，在70℃下乾燥10分鐘而得到偏振板。The polarizing plate was sandwiched between the polyester film of each of the examples and the comparative examples and the saponified cellulose halide, and an aqueous PVA solution was applied between the polarizing plate/polyester and the cellulose halide/polarizing plate ( The fully saponified PVA 5% aqueous solution) was bonded by pressure-bonding with a nip roll, and then dried at 70 ° C for 10 minutes to obtain a polarizing plate.

將所得到的偏振板作為各實施例及比較例的偏振板。The obtained polarizing plate was used as the polarizing plate of each of Examples and Comparative Examples.

將所得到的偏振板2對按照相對於液晶單元使聚酯膜成為外側，並使偏振片的吸收軸正交配置的方式安裝到具有連續光源（白色LED）或不連續光源（冷陰極管）作為背光源的液晶顯示裝置中，將光的透射度調整至達到50%。The obtained polarizing plate 2 is attached to have a continuous light source (white LED) or a discontinuous light source (cold cathode tube) so that the polyester film is made outward with respect to the liquid crystal cell and the absorption axes of the polarizing plates are arranged orthogonally. In the liquid crystal display device as a backlight, the transmittance of light is adjusted to 50%.

將所得到液晶顯示裝置作為各實施例及比較例的圖像顯示裝置。The obtained liquid crystal display device was used as an image display device of each of Examples and Comparative Examples.

＜虹斑的評估＞<Evaluation of rainbow spots>

通過從一側使用連續光源（白色LED）、不連續光源（冷陰極管）入射光，從相反側透過偏光太陽鏡通過目視數出所產生的虹的條數來評估虹斑。The rainbow spot is evaluated by visually counting the number of generated rainbows from the opposite side by using a continuous light source (white LED), a discontinuous light source (cold cathode tube), and transmitting the polarized sunglasses from the opposite side.

另外，虹斑的評估從偏振板的法線方向和傾斜方向（與法線成45°）的兩個方向進行觀察。 A：完全看不見虹斑 B：看不見虹斑 C：幾乎看不見虹斑 D：能看見虹斑In addition, the evaluation of the rainbow spot was observed from two directions of the normal direction of the polarizing plate and the oblique direction (45° from the normal). A: I can't see the rainbow spot at all. B: I can't see the rainbow spot. C: I can't see the rainbow spot. D: I can see the rainbow spot.

將結果示於下述表2中。The results are shown in Table 2 below.

[表1] [Table 1]

[表2] [Table 2]

由上述表1及表2獲知，本發明的聚酯膜的傷痕少，搬送時的裂紋、斷裂少，安裝到液晶顯示裝置中時能夠抑制虹斑的產生。As is apparent from the above Tables 1 and 2, the polyester film of the present invention has less scratches and less cracks and breakage during transportation, and can suppress generation of rainbow spots when mounted in a liquid crystal display device.

另一方面，由比較例1可知，在向與搬送方向正交的方向的拉伸倍率低於本發明的下限值的製造條件下製造的Re低於本發明的下限值的聚酯膜安裝到液晶顯示裝置中時產生虹斑。On the other hand, in Comparative Example 1, it is understood that the polyester film produced under the production conditions in which the draw ratio in the direction orthogonal to the conveyance direction is lower than the lower limit of the present invention is lower than the lower limit of the present invention. A rainbow spot is generated when mounted in a liquid crystal display device.

由比較例2可知，若在向與搬送方向正交的方向的拉伸倍率超過本發明的上限值的製造條件下製造，則在拉伸中產生斷裂，無法進行膜製作。When it is produced under the production conditions in which the draw ratio in the direction orthogonal to the conveyance direction exceeds the upper limit of the present invention, the film is broken during stretching, and film production cannot be performed.

由比較例3獲知，在向搬送方向的收縮超過本發明的上限值的製造條件下製造的Re/Rth低於本發明的下限值的聚酯膜安裝到液晶顯示裝置中時產生虹斑。According to Comparative Example 3, it was found that a polyester film produced when the Re/Rth manufactured under the manufacturing conditions in which the shrinkage in the conveyance direction exceeds the upper limit of the present invention is lower than the lower limit of the present invention is generated in the liquid crystal display device. .

由比較例4可知，在向搬送方向的收縮低於本發明的下限值的製造條件下製造的放置於平面上時的聚酯膜的浮起超過本發明的上限值的聚酯膜傷痕多，搬送時的裂紋、斷裂多。As is clear from Comparative Example 4, the polyester film which was produced on the flat surface when the shrinkage in the conveyance direction was lower than the lower limit of the present invention was higher than the upper limit of the present invention. Many, there are many cracks and breaks during transportation.

由比較例5可知，在不滿足式B1的左側的不等式的製造條件下製造的放置於平面上時的聚酯膜的浮起超過本發明的上限值的聚酯膜在搬送時的裂紋、斷裂多。In the case of the comparative example 5, the polyester film which is produced on the flat surface and which does not satisfy the inequality of the expression of the left side of the formula B1 is lifted, and the polyester film which exceeds the upper limit of the present invention is cracked at the time of conveyance. There are many breaks.

由比較例6可知，在不滿足式B1的右側的不等式的製造條件下製造的放置於平面上時的聚酯膜的浮起超過本發明的上限值的聚酯膜傷痕多，搬送時的裂紋、斷裂多。As is clear from the comparative example 6, the polyester film which was produced on the flat surface which was produced under the manufacturing conditions of the inequality of the right side of the formula B1 had a large amount of scratches on the polyester film which exceeded the upper limit of the present invention, and was transported. Cracks and fractures.

由比較例7可知，厚度低於本發明的下限值的聚酯膜因搬送中的張力而發生斷裂。As is clear from Comparative Example 7, the polyester film having a thickness lower than the lower limit of the present invention was broken by the tension during transportation.

由比較例8可知，與配向方向正交的方向的熱收縮率超過本發明的上限值的聚酯膜在搬送時的裂紋、斷裂多。As is clear from Comparative Example 8, the polyester film having a heat shrinkage ratio in a direction orthogonal to the direction of the alignment exceeding the upper limit of the present invention has many cracks and cracks during conveyance.

另外，通過與未拉伸聚酯膜1及2同樣的方法確認通過本發明的聚酯膜的製造方法製造的各實施例的聚酯膜的長度方向的折射率均為1.590以下，結晶化度均超過5%。In the same manner as the unstretched polyester films 1 and 2, it was confirmed that the polyester film of each of the examples produced by the method for producing a polyester film of the present invention had a refractive index in the longitudinal direction of 1.590 or less and a degree of crystallization. Both exceed 5%.

此外，通過以下的方法確認通過本發明的聚酯膜的製造方法製造的各實施例的聚酯膜進行了單軸配向。Further, it was confirmed by the following method that the polyester film of each of the examples produced by the method for producing a polyester film of the present invention was subjected to uniaxial alignment.

即，用阿貝折射率計測定長度方向、寬度方向、厚度方向的折射率，通過確認長度方向的折射率為1.590以下，寬度方向的折射率與其相比充分大，厚度方向的折射率與其相比充分小，確認各實施例的聚酯膜進行了單軸配向。In other words, the refractive index in the longitudinal direction, the width direction, and the thickness direction is measured by an Abbe refractometer, and it is confirmed that the refractive index in the longitudinal direction is 1.590 or less, and the refractive index in the width direction is sufficiently larger than that in the thickness direction. The ratio was sufficiently small, and it was confirmed that the polyester films of the respective examples were uniaxially aligned.

無。no.

Claims

一種聚酯膜，其厚度為10～150μm，面內方向的延遲Re及厚度方向的延遲Rth為3000～30000nm， Re/Rth超過0.8且為2.5以下，與配向方向正交的方向的熱收縮率為0.6%以下，其中，將卷曲成卷狀的聚酯膜的最外表層開卷並切出500mm見方的聚酯膜放置在平面上時的聚酯膜的浮起為1.8mm以下。A polyester film having a thickness of 10 to 150 μm, a retardation Re in the in-plane direction, and a retardation Rth in the thickness direction of 3,000 to 30,000 nm, and a Re/Rth exceeding 0.8 and 2.5 or less, and a heat shrinkage ratio in a direction orthogonal to the alignment direction It is 0.6% or less, in which the outermost surface layer of the polyester film curled into a roll shape is unwound and the polyester film which cut out the 500 mm square polyester film is set to the plane, and the floating of the polyester film is 1.8 mm or less.

根據申請專利範圍第1項所述的聚酯膜，其中，下述式A所表示的與配向方向正交的方向的熱收縮率不均為0.4%以下，式A：（與配向方向正交的方向的熱收縮率不均）=（配向方向的3點處的在150℃下加熱30分鐘後的與配向方向正交的方向的熱收縮率的最大值與最小值之差）/（配向方向的3點處的在150℃下加熱30分鐘後的與配向方向正交的方向的熱收縮率的平均值）×100%。The polyester film according to the first aspect of the invention, wherein the heat shrinkage ratio in the direction orthogonal to the alignment direction represented by the following formula A is not more than 0.4%, and the formula A: (orthogonal to the alignment direction) (The heat shrinkage rate unevenness in the direction) = (the difference between the maximum value and the minimum value of the heat shrinkage rate in the direction orthogonal to the alignment direction after heating at 150 ° C for 30 minutes at the three points in the alignment direction) / (Orientation) The average value of the heat shrinkage ratio in the direction orthogonal to the alignment direction after heating at 150 ° C for 30 minutes at three points in the direction was ×100%.

一種聚酯膜的製造方法，其包括以下步驟：使用具有多個邊夾持膜邊在一對軌道間移動的夾子的拉伸機，在各軌道上同時進行由縮短該夾子間的距離引起的向膜搬送方向的收縮、和由擴大該夾子移動的一對軌道間的距離引起的向與膜搬送方向正交的方向的拉伸的步驟，該向膜搬送方向的收縮率和向與膜搬送方向正交的方向的拉伸倍率在拉伸中總是滿足下述式B1的關係，並且滿足下述式B2及式B3， [數學式1]･･･式B1 [數學式2]･･･式B2 [數學式3]･･･式B3 式B1、B2及B3中， x表示拉伸機的入口的寬度，單位為mm； x’表示拉伸中的各位置處的聚酯膜的寬度，單位為mm； x_max 表示拉伸中的聚酯膜的最大寬度，單位為mm； y表示拉伸機的入口處的各軌道上的夾子間的距離，單位為mm； y’表示拉伸中的各位置處的各軌道上的夾子間的距離，單位為mm； y_min 表示拉伸中的各軌道上的夾子間的距離的最小值，單位為mm。A method for producing a polyester film, comprising the steps of: simultaneously using a stretching machine having a plurality of clips that sandwich a film while moving between a pair of rails on each rail by shortening the distance between the clips The shrinkage in the film transport direction and the stretching in the direction orthogonal to the film transport direction caused by the distance between the pair of rails that expand the clip movement, the shrinkage rate in the film transport direction and the transfer to the film The stretching ratio in the direction orthogonal to the direction always satisfies the relationship of the following formula B1 in stretching, and satisfies the following formula B2 and formula B3, [Formula 1] ・・・式B1 [Math 2] ・・・式B2 [Math 3] ・・・式B3 In the formulas B1, B2 and B3, x represents the width of the inlet of the stretching machine, and the unit is mm; x' represents the width of the polyester film at each position during stretching, in mm; x _max Indicates the maximum width of the polyester film in stretching, in mm; y represents the distance between the clips on each track at the entrance of the stretching machine, in mm; y' represents each position at each position in the stretching The distance between the clips on the track, in mm; y _min represents the minimum distance between the clips on each track in the stretch, in mm.

一種聚酯膜的製造方法，其包括以下步驟：使用具有多個邊夾持膜邊在一對軌道間移動的夾子的拉伸機，在各軌道上同時進行由縮短該夾子間的距離引起的向膜搬送方向的收縮、和由擴大該夾子移動的一對軌道間的距離引起的向與膜搬送方向正交的方向的拉伸的步驟，該向膜搬送方向的收縮率和向與膜搬送方向正交的方向的拉伸倍率在拉伸中總是滿足下述式B1的關係、並且滿足下述式B2及式B3，其中，該聚酯膜的厚度為10～150μm，該聚酯膜的與配向方向正交的方向的熱收縮率為0.6%以下； [數學式4]･･･式B1 [數學式5]･･･式B2 [數學式6]･･･式B3 式B1、B2及B3中， x表示拉伸機的入口的寬度，單位為mm； x’表示拉伸中的各位置處的聚酯膜的寬度，單位為mm； x_max 表示拉伸中的聚酯膜的最大寬度，單位為mm； y表示拉伸機的入口處的各軌道上的夾子間的距離，單位為mm； y’表示拉伸中的各位置處的各軌道上的夾子間的距離，單位為mm； y_min 表示拉伸中的各軌道上的夾子間的距離的最小值，單位為mm。A method for producing a polyester film, comprising the steps of: simultaneously using a stretching machine having a plurality of clips that sandwich a film while moving between a pair of rails on each rail by shortening the distance between the clips The shrinkage in the film transport direction and the stretching in the direction orthogonal to the film transport direction caused by the distance between the pair of rails that expand the movement of the clip, the shrinkage rate in the film transport direction and the transfer to the film The stretching ratio in the direction orthogonal to the direction always satisfies the relationship of the following formula B1 in stretching, and satisfies the following formula B2 and formula B3, wherein the polyester film has a thickness of 10 to 150 μm, and the polyester film The heat shrinkage rate in the direction orthogonal to the alignment direction is 0.6% or less; [Math 4] ・・・式B1 [Math 5] ・・・式B2 [Math 6] ・・・式B3 In the formulas B1, B2 and B3, x represents the width of the inlet of the stretching machine, and the unit is mm; x' represents the width of the polyester film at each position during stretching, in mm; x _max Indicates the maximum width of the polyester film in stretching, in mm; y represents the distance between the clips on each track at the entrance of the stretching machine, in mm; y' represents each position at each position in the stretching The distance between the clips on the track, in mm; y _min represents the minimum distance between the clips on each track in the stretch, in mm.

根據申請專利範圍第3項或第4項所述的聚酯膜的製造方法，其在拉伸平均溫度T1下同時進行該向膜搬送方向的收縮和該向與膜搬送方向正交的方向的拉伸後，包括在熱定型溫度T2≥T1+30℃下進行加熱的熱定型步驟；其中，T1及T2的單位為℃。The method for producing a polyester film according to the third or fourth aspect of the invention, wherein the shrinkage in the film transport direction and the direction orthogonal to the film transport direction are simultaneously performed at the stretching average temperature T1. After stretching, a heat setting step of heating is performed at a heat setting temperature T2 ≥ T1 + 30 ° C; wherein the units of T1 and T2 are °C.

根據申請專利範圍第5項所述的聚酯膜的製造方法，其中，邊進行向膜搬送方向的收縮邊進行該熱定型。The method for producing a polyester film according to the fifth aspect of the invention, wherein the heat setting is performed while performing shrinkage in a film transport direction.

根據申請專利範圍第5項所述的聚酯膜的製造方法，其中，該熱定型溫度T2超過T1+50℃。The method for producing a polyester film according to claim 5, wherein the heat setting temperature T2 exceeds T1 + 50 °C.

一種偏振板，其包含偏振片、和申請專利範圍第1項所述的聚酯膜。A polarizing plate comprising a polarizing plate, and the polyester film according to claim 1 of the patent application.

一種圖像顯示裝置，其具有申請專利範圍第1項所述的聚酯膜、或申請專利範圍第8項所述的偏振板。An image display device comprising the polyester film according to claim 1 or the polarizing plate according to item 8 of the patent application.

一種硬塗膜，其包含申請專利範圍第1項所述的聚酯膜。A hard coat film comprising the polyester film of claim 1 of the patent application.

一種觸摸面板，其具有申請專利範圍第1項所述的聚酯膜、申請專利範圍第8項所述的偏振板、或申請專利範圍第10項所述的硬塗膜。A touch panel comprising the polyester film according to claim 1 of the invention, the polarizing plate according to claim 8 or the hard coat film according to claim 10 of the patent application.