JP6926616B2 - Biaxially oriented laminated polyester film and magnetic recording medium - Google Patents

Biaxially oriented laminated polyester film and magnetic recording medium Download PDF

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JP6926616B2
JP6926616B2 JP2017081197A JP2017081197A JP6926616B2 JP 6926616 B2 JP6926616 B2 JP 6926616B2 JP 2017081197 A JP2017081197 A JP 2017081197A JP 2017081197 A JP2017081197 A JP 2017081197A JP 6926616 B2 JP6926616 B2 JP 6926616B2
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東大路　卓司
卓司 東大路
中森　ゆか里
ゆか里 中森
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Toray Industries Inc
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本発明は、走行性やスリット性、寸法安定性および表面性に優れた二軸配向積層ポリエステルフィルムに関するものであり、高精細な表面性が必要な光学用や各種離型フィルム、次世代熱転写リボン用フィルム、データストレージなどの塗布型磁気記録媒体のベースフィルムに好適に用いることができる二軸配向積層ポリエステルフィルムに関する。 The present invention relates to a biaxially oriented laminated polyester film having excellent running performance, slitting property, dimensional stability and surface property, and is used for optics and various release films that require high-definition surface property, and a next-generation thermal transfer ribbon. The present invention relates to a biaxially oriented laminated polyester film that can be suitably used as a base film for a coating type magnetic recording medium such as a film for data storage and a data storage.

二軸配向ポリエステルフィルムはその優れた熱特性、寸法安定性、機械特性および表面形態の制御のし易さから各種用途に使用されており、特に磁気記録媒体などの支持体としての有用性がよく知られている。磁気記録媒体には常に高密度記録化が要求され、更なる高密度記録を達成するためには、磁性層の薄膜化や微粒子磁性体を使用し磁性層表面の平滑性をさらに向上させることは有効である。 Biaxially oriented polyester films are used in various applications due to their excellent thermal properties, dimensional stability, mechanical properties, and easy control of surface morphology, and are particularly useful as supports for magnetic recording media and the like. Are known. High-density recording is always required for magnetic recording media, and in order to achieve higher-density recording, it is necessary to make the magnetic layer thinner or use fine-grained magnetic material to further improve the smoothness of the magnetic layer surface. It is valid.

近年の強磁性六方晶フェライト粉末を用いてなる磁気記録媒体用支持体においては、磁性層や非磁性層、バックコート層、さらには支持体自体の薄膜化に伴い平滑面のみならず走行面の粗面化が制約されている。製造過程で磁気記録媒体としてロール状態で保存する場合、走行面に形成されている突起が磁性面に転写し、平滑な磁性層表面に窪みを形成させ磁性層表面の平滑性が悪化し電磁変換特性が低下するといった問題がある。磁性層表面の平滑性を高めるために支持体の走行面側に含有する粒子の小径化や低濃度化を図るだけでは、粒子の厚み方向の位置規制が不十分なために、依然として粗大突起が改善できない。また、走行面の平滑性を向上させると、走行性や巻き取り、スリット性、さらには表面の耐久性が不十分となる。 In recent years, in supports for magnetic recording media using ferromagnetic hexagonal ferrite powder, not only smooth surfaces but also running surfaces become thinner due to the thinning of magnetic layers, non-magnetic layers, backcoat layers, and the supports themselves. Roughening is restricted. When stored in a roll state as a magnetic recording medium in the manufacturing process, the protrusions formed on the traveling surface are transferred to the magnetic surface, forming dents on the smooth magnetic layer surface, and the smoothness of the magnetic layer surface deteriorates, resulting in electromagnetic conversion. There is a problem that the characteristics are deteriorated. Simply reducing the diameter and concentration of the particles contained on the running surface side of the support in order to improve the smoothness of the surface of the magnetic layer is insufficient to regulate the position of the particles in the thickness direction, so that coarse protrusions still occur. I can't improve. Further, if the smoothness of the traveling surface is improved, the traveling property, the winding property, the slit property, and the durability of the surface become insufficient.

したがって、走行性や巻き取り性、さらには表面の平滑性の両立といった特性の改善に対する要求は高密度記録化のためには常に発生する課題といえる。 Therefore, it can be said that the demand for improving the characteristics such as running performance, winding performance, and surface smoothness is always a problem for high-density recording.

上記課題を解決するために、例えば、特許文献１〜３では、微細な粒子により、フィルム表面の粗さや突起高さと個数を制御し優れた電磁変換特性とドロップアウト性能を有したポリエステルフィルムが提案されている。しかしながら、バックコート層側のベースフィルム表面に形成された特定の高さや大きさの突起を規定しても磁性層やバックコート層が薄く高精細な表面を有する強磁性六方晶フェライト粉末を用いてなる磁気記録媒体用支持体に用いる場合には、依然として粗大突起の低減には至らず、転写による磁性面の平滑性の低下を解消できず、さらに添加粒子の小径化、少量添加による走行性や巻き取り性に問題が残っているのが実情である。また、微細な粒子とコーティング層によりフィルム両表面のうねり制御により電磁変換特性と走行性の両立を試みたポリエステルフィルム（例えば特許文献４）も提案されているが、磁性層の平滑性と走行性や巻き取り性の両立には至っておらず、また、コーティング層の耐久性が乏しく、磁気記録媒体の製造工程でフィルム表面の傷つき性やコーティング層の削れ粉による工程内ロールの汚染の問題がある。 In order to solve the above problems, for example, Patent Documents 1 to 3 propose a polyester film having excellent electromagnetic conversion characteristics and dropout performance by controlling the roughness, protrusion height and number of film surfaces by using fine particles. Has been done. However, even if protrusions of a specific height and size formed on the surface of the base film on the backcoat layer side are specified, a ferromagnetic hexagonal ferrite powder having a thin magnetic layer and backcoat layer and a high-definition surface is used. When used for a support for a magnetic recording medium, the coarse protrusions cannot be reduced, the decrease in the smoothness of the magnetic surface due to transfer cannot be eliminated, the diameter of the added particles is reduced, and the running performance is increased by adding a small amount. The reality is that there are still problems with take-up performance. Further, a polyester film (for example, Patent Document 4) in which an attempt is made to achieve both electromagnetic conversion characteristics and runnability by controlling waviness on both surfaces of the film with fine particles and a coating layer has been proposed, but the smoothness and runnability of the magnetic layer have also been proposed. In addition, the durability of the coating layer is poor, and there is a problem that the film surface is scratched in the manufacturing process of the magnetic recording medium and the roll in the process is contaminated by the shavings of the coating layer. ..

また近年、プリント配線基板、半導体パッケージ、フレキシブル基板などの製造に、ポリエステルフィルムを基材として用いるドライフィルムレジスト（ＤＦＲ）が多く用いられる。一般的に、ＤＦＲは、感光層（フォトレジスト層）が、ポリエステルフィルムからなる基材フィルムとポリオレフィンフィルムなどからなる保護フィルム（カバーフィルム）との間に挟まれたサンドイッチ構造をしている。このＤＦＲを用いて導体回路を作製するには、一般的に次のような操作が行われる。 Further, in recent years, a dry film resist (DFR) using a polyester film as a base material is often used for manufacturing printed wiring boards, semiconductor packages, flexible substrates and the like. Generally, the DFR has a sandwich structure in which a photosensitive layer (photoresist layer) is sandwiched between a base film made of a polyester film and a protective film (cover film) made of a polyolefin film or the like. In order to manufacture a conductor circuit using this DFR, the following operations are generally performed.

すなわち、ＤＦＲから保護フィルムを剥離し、露出したレジスト層の表面と、基板上の例えば銅箔などの導電性基材層の表面とが密着するように、基板・導電性基材層とラミネートする。次に、導体回路パターンを焼き付けたレチクルを、ポリエステルフィルムからなる基材上に置き、その上から、感光性樹脂を主体としたレジスト層に光線を照射して、露光させる。その後、レクチルおよびポリエステルフィルムを剥離した後、溶剤によってレジスト層中の未反応分を溶解、除去する。次いで、酸などでエッチングを行い、導電性基材層中の露出した部分を溶解、除去する。この結果、レジスト層中の光反応部分とこの光反応部分に対応する導電性基材層部分がそのまま残ることになる。その後、残ったレジスト層を除去すれば、基板上の導体回路が形成されることになる。このような方法により導体回路が形成されるので、支持体としてポリエステルフィルムには、光線を邪魔なく透過できる高い光線透過性が要求される。 That is, the protective film is peeled off from the DFR and laminated with the substrate / conductive substrate layer so that the surface of the exposed resist layer and the surface of the conductive substrate layer such as copper foil on the substrate are in close contact with each other. .. Next, the reticle on which the conductor circuit pattern is printed is placed on a base material made of a polyester film, and the resist layer mainly composed of a photosensitive resin is irradiated with light rays to expose the resist layer. Then, after peeling off the lectyl and the polyester film, the unreacted component in the resist layer is dissolved and removed with a solvent. Next, etching is performed with an acid or the like to dissolve and remove the exposed portion in the conductive base material layer. As a result, the photoreactive portion in the resist layer and the conductive base material layer portion corresponding to the photoreactive portion remain as they are. After that, if the remaining resist layer is removed, a conductor circuit on the substrate will be formed. Since the conductor circuit is formed by such a method, the polyester film as a support is required to have high light transmittance capable of transmitting light rays without hindrance.

特に、近年、ＯＡ機器、ＩＴ機器など小型化、軽量化などに伴い、透過性に優れ、ヘイズが低く、高解像化を達成できるドライフィルムレジスト支持体用ポリエステルフィルが要求されている。 In particular, in recent years, along with the miniaturization and weight reduction of OA equipment and IT equipment, there is a demand for a polyester fill for a dry film resist support which has excellent transparency, low haze, and high resolution.

また、昨今のスマートフォンの普及に伴い、積層セラミックコンデンサーは小型・高容量化が進んでいる。そのため、積層セラミックコンデンサーの製造に用いる離型フィルムは、平滑性が高く、フィルム表面および内部に欠陥のないポリエステルフィルムの需要が急速に増えている。基材として使用されるポリエステルフィルムの表面特性として、その平滑面の品質が加工後のグリーンシート製品の品質にも影響を与えやすくなる傾向にある。また、粗面の品質も加工後のグリーンシート製品の品質に影響を与えやすくなる傾向にある。例えば、従来のポリエステルフィルムでは問題にならなかったが、グリーンシート加工がなされる平滑面のうねりが積層セラミックコンデンサーの品質に関係したり、また、粗面側の突起がグリーンシート製品を巻き上げた際にグリーンシートに転写し、きずやへこみを生じたりすることがある。 In addition, with the recent spread of smartphones, multilayer ceramic capacitors are becoming smaller and larger in capacity. Therefore, the release film used for manufacturing a multilayer ceramic capacitor has a high smoothness, and the demand for a polyester film having no defects on the film surface and inside is rapidly increasing. As a surface characteristic of the polyester film used as a base material, the quality of the smooth surface tends to easily affect the quality of the processed green sheet product. In addition, the quality of the rough surface tends to affect the quality of the processed green sheet product. For example, when the waviness of the smooth surface processed by the green sheet is related to the quality of the laminated ceramic capacitor, which was not a problem with the conventional polyester film, and when the protrusion on the rough surface side winds up the green sheet product. It may be transferred to a green sheet and cause scratches or dents.

また、液晶ディスプレイ等に使用される部材には偏光板、位相差偏光板または位相差板があり、偏光板は通常、偏光フィルム、表面保護フィルム、粘着剤層および離型フィルムより構成される。偏光フィルムは、沃素や二色性染料などの偏光素子をポリビニルアルコール系フィルムの如き親水性フィルムなどに吸着配向せしめた偏光軸と吸着軸とを有する偏光子を、上下よりセルロース系フィルムで被覆するか、あるいはアクリル系樹脂をコーティングすることによる構造を有する。表面保護フィルムは、ポリエステルフィルム等の透湿性が少なく、伸び等の変形が少ない透明なプラスチックフィルムが使用されている。表面保護フィルムと偏光フィルムは接着剤で被着されており、該接着剤は表面保護フィルムとは強固に接着するが、偏光フィルムとは経日でも容易に剥離し得るものが使用されている。粘着剤層は偏光フィルムを液晶セルに粘着するための感圧型粘着剤等よりなり、離型フィルムはポリエステルフィルム等で構成されている。このような偏光板の製造に際しては、予め原料である偏光フィルムの光の透過率や偏光度あるいはヘイズ等の光学特性を検査し使用してはいるものの、偏光板への製造工程での偏光フィルムへの機械的応力、異物混入あるいは付着等により欠陥が生じる可能性がある。このため最終製品での異物混入や欠陥検査では、クロスニコル法（２枚の偏光板を互いに偏光面を直交させ、その間にフィルムの長手方向、幅方向をそれぞれ直交する偏光板の偏光面に合わせて挟まれた状態での透過光を観察する方法）による人間の目視検査を行なっている。実際の偏光板の目視検査においては、正常な検光子の上に、その偏光面に対して偏光面が直交するように、検査対象の偏光板を、クロスニコル法における偏光子とフィルムとの代わりに重ねて置くと、原理的に、偏光板中の異物混入や欠陥という欠点箇所が輝点として現れるので、目視により欠点が検査できるというものである。しかしながら、現在、偏光板の離型フィルムとして用いられているニ軸配向ポリエステルフィルムは、クロスニコル法による偏光板検査時に、光漏れが生じやすく、正確な目視検査が困難となり、偏光板の異物混入や欠点である輝点を見落とす問題が生じている。 Further, the member used for a liquid crystal display or the like includes a polarizing plate, a retardation polarizing plate, or a retardation plate, and the polarizing plate is usually composed of a polarizing film, a surface protective film, an adhesive layer, and a release film. The polarizing film covers a polarizing element having a polarizing axis and an adsorption axis in which a polarizing element such as iodine or a dichroic dye is adsorbed and oriented on a hydrophilic film such as a polyvinyl alcohol-based film with a cellulose-based film from above and below. Or, it has a structure by coating with an acrylic resin. As the surface protective film, a transparent plastic film such as a polyester film having low moisture permeability and little deformation such as elongation is used. The surface protective film and the polarizing film are adhered with an adhesive, and the adhesive firmly adheres to the surface protective film, but a polarizing film that can be easily peeled off even after a long period of time is used. The pressure-sensitive adhesive layer is made of a pressure-sensitive pressure-sensitive adhesive or the like for adhering the polarizing film to the liquid crystal cell, and the release film is made of a polyester film or the like. In the production of such a polarizing plate, although the optical characteristics such as the light transmittance, the degree of polarization and the haze of the polarizing film as a raw material are inspected and used in advance, the polarizing film in the manufacturing process for the polarizing plate is used. Defects may occur due to mechanical stress on the surface, contamination with foreign matter, or adhesion to the surface. For this reason, in the inspection of foreign matter and defects in the final product, the cross Nicol method (two polarizing plates are orthogonal to each other in the plane of polarization, and the longitudinal direction and width direction of the film are aligned with the planes of polarization of the polarizing plates that are orthogonal to each other. A method of observing transmitted light while sandwiched between them) is used for visual inspection of humans. In the actual visual inspection of the polarizing plate, the polarizing plate to be inspected is replaced with the polarizer and the film in the cross Nicol method so that the plane of polarization is orthogonal to the plane of polarization on the normal analyzer. In principle, defects such as foreign matter mixed in the polarizing plate and defects appear as bright spots when placed on top of each other, so that the defects can be visually inspected. However, the biaxially oriented polyester film currently used as a release film for a polarizing plate tends to leak light during a polarizing plate inspection by the cross Nicol method, which makes accurate visual inspection difficult and causes foreign matter to be mixed in the polarizing plate. There is a problem of overlooking the bright spot, which is a drawback.

特許文献５および６では、ＤＦＲ基材である表面の平均粗さを平滑化したフィルムが開示されている。特許文献７では、積層セラミックコンデンサー用製造工程フィルムとして３層構成で特定の粒子を用いるフィルムについて開示されている。 Patent Documents 5 and 6 disclose a film in which the average roughness of the surface of the DFR base material is smoothed. Patent Document 7 discloses a film using specific particles in a three-layer structure as a manufacturing process film for a multilayer ceramic capacitor.

しかしながら、上記の特許文献５〜７に記載の技術では、ＤＦＲ基材として用いる場合には露光欠点抑制のために平滑化および透明性が十分ではない。また、積層セラミックコンデンサー用製造工程フィルムとして用いる場合には、グリーンシートがますます薄膜化するため、フィルム上に塗付などの加工がなされる面の波長１０μｍレベルの長波長の空間周波数密度で表される表面うねり指数がより重要になっており、また、粗面側の高い突起による加工面への転写抑制の観点で、粗面側の平滑性が十分ではない。 However, in the techniques described in Patent Documents 5 to 7, when used as a DFR substrate, smoothing and transparency are not sufficient in order to suppress exposure defects. In addition, when used as a manufacturing process film for multilayer ceramic capacitors, the green sheet becomes thinner and thinner, so it is represented by the spatial frequency density of a long wavelength of 10 μm level on the surface to be coated or processed on the film. The surface waviness index to be formed becomes more important, and the smoothness on the rough surface side is not sufficient from the viewpoint of suppressing transfer to the processed surface by the high protrusions on the rough surface side.

特開２０１２−１５３１００号公報Japanese Unexamined Patent Publication No. 2012-153100 特開２０１２−１５３０９９号公報Japanese Unexamined Patent Publication No. 2012-153099 特開２００１−３４１２６５号公報Japanese Unexamined Patent Publication No. 2001-341265 特開２０１３−２００９２７号公報Japanese Unexamined Patent Publication No. 2013-20927 特開２０１６−８７８５４号公報Japanese Unexamined Patent Publication No. 2016-87854 特開２０１５−２０８９３９号公報Japanese Unexamined Patent Publication No. 2015-208939 国際公開第２０１４／０６１４１０号パンフレットInternational Publication No. 2014/06410 Pamphlet

本発明者らは上記目的を解決するために鋭意検討を重ねた結果、走行面の磁性面への転写を抑制するために走行面の粗さや表面突起の高さと個数を制御し、粒子の小径化や低濃度化によって走行面の平滑性を極めても必ずしも磁性層表面の欠陥を低減できず、また、走行性を高いレベルで両立するには限界があると判断し、さらに検討を重ねた結果、走行面の特定の突起数の制御と該表面と反対側の表面性の制御によって電磁変換特性と巻き取り性の両立が可能となることを見出し本発明に到達した。 As a result of diligent studies to solve the above object, the present inventors controlled the roughness of the traveling surface and the height and number of surface protrusions in order to suppress the transfer of the traveling surface to the magnetic surface, and reduced the diameter of the particles. As a result of further studies, it was judged that the smoothness of the running surface could not necessarily be reduced even if the running surface was extremely smooth and the defects on the surface of the magnetic layer could not be reduced, and that there was a limit to achieving both running performance at a high level. The present invention has been found that it is possible to achieve both electromagnetic conversion characteristics and take-up performance by controlling the specific number of protrusions on the traveling surface and controlling the surface properties on the opposite side of the surface.

本発明の目的は、上記の問題を解決した、走行性やスリット性、寸法安定性に優れた二軸配向ポリエステルフィルムであって、磁気記録媒体とした際に平滑な磁性層を有すると共に温度や湿度の環境変化や保存による寸法変化が小さく、エラーレートが少ない電磁変換特性に優れた高密度磁気記録媒体となる二軸配向積層ポリエステルフィルムを安定に提供することにある。また離型・工程用あるいは光学部材用として加工が施される面の長波長の表面うねりが小さく、かつ、その反対面の突起高さを制御することで、平滑性や透明性に優れるポリエステルフィルムを提供することにある。 An object of the present invention is a biaxially oriented polyester film having excellent running performance, slitting property, and dimensional stability, which solves the above problems, has a smooth magnetic layer when used as a magnetic recording medium, and has a temperature and temperature. An object of the present invention is to stably provide a biaxially oriented laminated polyester film which is a high-density magnetic recording medium having excellent electromagnetic conversion characteristics with little error rate and small dimensional change due to environmental change of humidity and storage. In addition, a polyester film that has small long-wavelength surface waviness on the surface to be processed for mold release / process or optical members, and has excellent smoothness and transparency by controlling the height of protrusions on the opposite surface. Is to provide.

上記課題を解決するための本発明は、次の各構成を特徴とするものである。
（１）表層を構成する少なくともＡ層とＢ層の２層を含む二軸配向積層ポリエステルフィルムであって、Ａ層厚みがＢ層厚みより大きく、基準面からのしきい値６０ｎｍにおける突起個数が１０個／５０μｍ２以下であり、かつ、Ｂ層表面における三次元粗さ計による基準面から高さ６０ｎｍ以上の突起密度（Ｍ６０）が１００個／ｍｍ２未満である、二軸配向積層ポリエステルフィルム。
（２）前記Ａ層表面の中心線表面粗さＲａが０．１〜３ｎｍである、上記（１）記載の二軸配向積層ポリエステルフィルム。
（３）前記Ａ層表面における波長９．６５μｍにおけるパワースペクトル密度（ＰＳＤ）が１，０００〜５０，０００ｎｍ３の範囲にある、上記（１）または（２）に記載の二軸配向積層ポリエステルフィルム。
（４）前記Ｂ層の積層厚み（ｔ）が０．５〜２．０μｍであり、かつ、該層に含有される粒子の最大粒子径（Ｄ）との比（ｔ／Ｄ）が５以上１０以下である、上記（１）〜（３）のいずれかに記載の二軸配向積層ポリエステルフィルム。
（５）三次元粗さ計によるＢ層表面の突起密度が以下の関係を満足する、上記（１）〜（４）のいずれかに記載の二軸配向積層ポリエステルフィルム。 The present invention for solving the above problems is characterized by the following configurations.
(1) A biaxially oriented laminated polyester film containing at least two layers, A layer and B layer, which constitute the surface layer, in which the thickness of the A layer is larger than the thickness of the B layer and the number of protrusions at a threshold value of 60 nm from the reference plane is large. A biaxially oriented laminated polyester film having a protrusion density (M60) of 10 pieces / 50 μm 2 or less and a height of 60 nm or more from the reference surface by a three-dimensional roughness meter on the B layer surface of 100 pieces / mm 2 or less. ..
(2) The biaxially oriented laminated polyester film according to (1) above, wherein the center line surface roughness Ra of the surface of the A layer is 0.1 to 3 nm.
(3) The biaxially oriented laminated polyester film according to (1) or (2) above, wherein the power spectral density (PSD) at a wavelength of 9.65 μm on the surface of the layer A is in the range of 1,000 to 50,000 nm 3. ..
(4) The laminated thickness (t) of the B layer is 0.5 to 2.0 μm, and the ratio (t / D) of the particles contained in the layer to the maximum particle size (D) is 5 or more. The biaxially oriented laminated polyester film according to any one of (1) to (3) above, which is 10 or less.
(5) The biaxially oriented laminated polyester film according to any one of (1) to (4) above, wherein the protrusion density on the surface of the B layer by a three-dimensional roughness meter satisfies the following relationship.

０．４＜（Ｍ６０／Ｍ１０）×１００＜５
（但し、Ｍ１０（個／ｍｍ２）：基準面から高さ１０ｎｍ以上の突起密度、Ｍ６０（個／ｍｍ２）:基準面から高さ６０ｎｍ以上の突起密度）
（６）厚みが３．５〜４．５μｍである、上記（１）〜（５）のいずれかに記載の二軸配向積層ポリエステルフィルム。
（７）幅方向の湿度膨張係数が０〜８ｐｐｍ／％ＲＨである、上記（１）〜（６）のいずれかに記載の二軸配向積層ポリエステルフィルム。
（８）３層以上の積層構造からなる、上記（１）〜（７）のいずれかに記載の二軸配向積層ポリエステルフィルム。
（９）塗布型デジタル記録方式の磁気記録媒体用ベースフィルムに用いられる、上記（１）〜（８）のいずれかに記載の二軸配向積層ポリエステルフィルム。
（１０）上記（１）〜（９）のいずれかに記載の二軸配向積層ポリエステルフィルムを用いた磁気記録媒体。
（１１）離型用または工程用フィルムとして用いられる、上記（１）〜（８）のいずれかに記載の二軸配向積層ポリエステルフィルム。
（１２）ドライフィルムレジスト基材用フィルムとして用いられる、上記（１１）に記載の二軸配向積層ポリエステルフィルム。
（１３）積層セラミックコンデンサーを製造する工程においてグリーンシート成形の支持体として用いられる、上記（１１）に記載の二軸配向積層ポリエステルフィルム。
（１４）偏光板離型用フィルムとして用いられる、上記（１１）に記載の二軸配向積層ポリエステルフィルム。
（１５）光学部材用フィルムとして用いられる、上記（１）〜（８）のいずれかに記載の二軸配向積層ポリエステルフィルム。 0.4 <(M60 / M10) x 100 <5
(However, M10 (pieces / mm 2 ): protrusion density of height 10 nm or more from the reference surface, M60 (pieces / mm 2 ): protrusion density of height 60 nm or more from the reference surface)
(6) The biaxially oriented laminated polyester film according to any one of (1) to (5) above, which has a thickness of 3.5 to 4.5 μm.
(7) The biaxially oriented laminated polyester film according to any one of (1) to (6) above, wherein the humidity expansion coefficient in the width direction is 0 to 8 ppm /% RH.
(8) The biaxially oriented laminated polyester film according to any one of (1) to (7) above, which has a laminated structure of three or more layers.
(9) The biaxially oriented laminated polyester film according to any one of (1) to (8) above, which is used as a base film for a coating type digital recording type magnetic recording medium.
(10) A magnetic recording medium using the biaxially oriented laminated polyester film according to any one of (1) to (9) above.
(11) The biaxially oriented laminated polyester film according to any one of (1) to (8) above, which is used as a film for mold release or a process.
(12) Dry film The biaxially oriented laminated polyester film according to (11) above, which is used as a film for a resist base material.
(13) The biaxially oriented laminated polyester film according to (11) above, which is used as a support for forming a green sheet in a process of manufacturing a laminated ceramic capacitor.
(14) The biaxially oriented laminated polyester film according to (11) above, which is used as a polarizing plate release film.
(15) The biaxially oriented laminated polyester film according to any one of (1) to (8) above, which is used as a film for an optical member.

本発明の二軸配向積層ポリエステルフィルムは、走行性やスリット性、寸法安定性に優れ、磁気記録媒体とした際に平滑な磁性層を有すると共に温度や湿度の環境変化や保存による寸法変化が小さい、エラーレートが少なく電磁変換特性に優れた高密度磁気記録媒体となる二軸配向積層ポリエステルフィルムを得ることができるほか、光学用や各種離型フィルムとして好適に用いることができる。 The biaxially oriented laminated polyester film of the present invention is excellent in running performance, slit property, and dimensional stability, has a smooth magnetic layer when used as a magnetic recording medium, and has small dimensional changes due to environmental changes in temperature and humidity and storage. In addition to being able to obtain a biaxially oriented laminated polyester film which is a high-density magnetic recording medium having a low error rate and excellent electromagnetic conversion characteristics, it can also be suitably used for optical use and various release films.

本発明において用いるポリエステルとしては、例えば、芳香族ジカルボン酸、脂環族ジカルボン酸または脂肪族ジカルボン酸などの酸成分やジオール成分を構成単位（重合単位）とするポリマーで構成されたものを用いることができる。 As the polyester used in the present invention, for example, a polyester composed of an acid component such as an aromatic dicarboxylic acid, an alicyclic dicarboxylic acid or an aliphatic dicarboxylic acid or a polymer having a diol component as a constituent unit (polymerization unit) is used. Can be done.

芳香族ジカルボン酸成分としては、例えば、テレフタル酸、イソフタル酸、フタル酸、１，４−ナフタレンジカルボン酸、１，５−ナフタレンジカルボン酸、２，６−ナフタレンジカルボン酸、４，４’−ジフェニルジカルボン酸、４，４’−ジフェニルエーテルジカルボン酸、４，４’−ジフェニルスルホンジカルボン酸等を用いることができ、なかでも好ましくは、テレフタル酸、フタル酸、２，６−ナフタレンジカルボン酸を用いることができる。脂環族ジカルボン酸成分としては、例えば、シクロヘキサンジカルボン酸等を用いることができる。脂肪族ジカルボン酸成分としては、例えば、アジピン酸、スベリン酸、セバシン酸、ドデカンジオン酸等を用いることができる。これらの酸成分は一種のみを用いてもよく、二種以上を併用してもよい。 Examples of the aromatic dicarboxylic acid component include terephthalic acid, isophthalic acid, phthalic acid, 1,4-naphthalenedicarboxylic acid, 1,5-naphthalenedicarboxylic acid, 2,6-naphthalenedicarboxylic acid, and 4,4'-diphenyldicarboxylic acid. Acids, 4,4'-diphenyl ether dicarboxylic acid, 4,4'-diphenylsulfone dicarboxylic acid and the like can be used, and among them, terephthalic acid, phthalic acid and 2,6-naphthalenedicarboxylic acid can be used. .. As the alicyclic dicarboxylic acid component, for example, cyclohexanedicarboxylic acid or the like can be used. As the aliphatic dicarboxylic acid component, for example, adipic acid, suberic acid, sebacic acid, dodecandioic acid and the like can be used. Only one kind of these acid components may be used, or two or more kinds thereof may be used in combination.

ジオール成分としては、例えば、エチレングリコール、１，２−プロパンジオール、１，３−プロパンジオール、ネオペンチルグリコール、１，３−ブタンジオール、１，４−ブタンジオール、１，５−ペンタンジオール、１，６−ヘキサンジオール、１，２−シクロヘキサンジメタノール、１，３−シクロヘキサンジメタノール、１，４−シクロヘキサンジメタノール、ジエチレングリコール、トリエチレングリコール、ポリアルキレングリコール、２，２’−ビス（４’−β−ヒドロキシエトキシフェニル）プロパン等を用いることができ、なかでも、エチレングリコール、１，４−ブタンジオール、１，４−シクロヘキサンジメタノール、ジエチレングリコール等を好ましく用いることができ、特に好ましくは、エチレングリコール等を用いることができる。これらのジオール成分は一種のみを用いてもよく、二種以上を併用してもよい。 Examples of the diol component include ethylene glycol, 1,2-propanediol, 1,3-propanediol, neopentyl glycol, 1,3-butanediol, 1,4-butanediol, 1,5-pentanediol, and 1, , 6-Hexanediol, 1,2-Cyclohexanedimethanol, 1,3-Cyclohexanedimethanol, 1,4-Cyclohexanedimethanol, Diethylene glycol, Triethylene glycol, Polyalkylene glycol, 2,2'-bis (4'-) β-Hydroxyethoxyphenyl) propane and the like can be used, and among them, ethylene glycol, 1,4-butanediol, 1,4-cyclohexanedimethanol, diethylene glycol and the like can be preferably used, and ethylene glycol is particularly preferable. Etc. can be used. Only one kind of these diol components may be used, or two or more kinds thereof may be used in combination.

ポリエステルには、ラウリルアルコール、イソシアン酸フェニル等の単官能化合物が共重合されていてもよいし、トリメリット酸、ピロメリット酸、グリセロール、ペンタエリスリトール、２，４−ジオキシ安息香酸、等の３官能化合物などが、過度に分枝や架橋をせずポリマーが実質的に線状である範囲内で共重合されていてもよい。さらに酸成分、ジオール成分以外に、ｐ−ヒドロキシ安息香酸、ｍ−ヒドロキシ安息香酸、２，６−ヒドロキシナフトエ酸などの芳香族ヒドロキシカルボン酸およびｐ−アミノフェノール、ｐ−アミノ安息香酸などを本発明の効果が損なわれない程度の少量であればさらに共重合せしめることができる。 The polyester may be copolymerized with a monofunctional compound such as lauryl alcohol or phenyl isocyanate, or may be trifunctional such as trimellitic acid, pyromellitic acid, glycerol, pentaerythritol, 2,4-dioxybenzoic acid and the like. Compounds and the like may be copolymerized within a range in which the polymer is substantially linear without excessive branching or cross-linking. Further, in addition to the acid component and the diol component, the present invention comprises aromatic hydroxycarboxylic acids such as p-hydroxybenzoic acid, m-hydroxybenzoic acid and 2,6-hydroxynaphthoic acid, and p-aminophenol and p-aminobenzoic acid. If the amount is so small that the effect of the above is not impaired, further copolymerization can be performed.

ポリマーの共重合割合はＮＭＲ法（核磁気共鳴法）や顕微ＦＴ−ＩＲ法（フーリエ変換顕微赤外分光法）を用いて調べることができる。 The copolymerization ratio of the polymer can be examined by using an NMR method (nuclear magnetic resonance method) or a microscopic FT-IR method (Fourier transform microinfrared spectroscopy).

ポリエステルは、二軸延伸を施せること、および、寸法安定性などの本発明の効果を発現するために、ガラス転移温度が１５０℃未満のものを好適に使用できる。本発明において用いるポリエステルとしては、ポリエチレンテレフタレート、ポリエチレンナフタレート（ポリエチレン−２，６−ナフタレート）が好ましく、また、これらの共重合体や変性体でもよく、他の熱可塑性樹脂とのポリマーアロイでもよい。ここでいうポリマーアロイとは高分子多成分系のことであり、共重合によるブロックコポリマーであってもよいし、混合などによるポリマーブレンドでもよい。本発明で用いるポリエステルとしては特に、結晶子サイズや結晶配向度を高めるプロセスが適用しやすいことから主成分がポリエチレンテレフタレートであることがより好ましい。ここで、主成分とはフィルム組成中８０質量％以上を占める成分のことをいう。 As the polyester, a polyester having a glass transition temperature of less than 150 ° C. can be preferably used in order to be able to perform biaxial stretching and to exhibit the effects of the present invention such as dimensional stability. The polyester used in the present invention is preferably polyethylene terephthalate or polyethylene naphthalate (polyethylene-2,6-naphthalate), and may be a copolymer or modified product of these, or may be a polymer alloy with another thermoplastic resin. .. The polymer alloy referred to here is a polymer multi-component system, and may be a block copolymer by copolymerization or a polymer blend by mixing or the like. As the polyester used in the present invention, it is more preferable that the main component is polyethylene terephthalate because a process for increasing the crystallite size and the degree of crystal orientation can be easily applied. Here, the main component means a component that occupies 80% by mass or more in the film composition.

本発明で用いるポリエチレンテレフタレートをポリマーアロイとする場合、他の熱可塑性樹脂は、ポリエステルと相溶するポリマーが好ましく、ポリエーテルイミド樹脂などがより好ましい。ポリエーテルイミド樹脂としては、例えば以下で示すものを用いることができる。 When the polyethylene terephthalate used in the present invention is a polymer alloy, the other thermoplastic resin is preferably a polymer compatible with polyester, more preferably a polyetherimide resin or the like. As the polyetherimide resin, for example, those shown below can be used.

Figure 0006926616
Figure 0006926616

（ただし、上記式中Ｒ１は、６〜３０個の炭素原子を有する２価の芳香族または脂肪族残基、Ｒ２は６〜３０個の炭素原子を有する２価の芳香族残基、２〜２０個の炭素原子を有するアルキレン基、２〜２０個の炭素原子を有するシクロアルキレン基、および２〜８個の炭素原子を有するアルキレン基で連鎖停止されたポリジオルガノシロキサン基からなる群より選択された２価の有機基である。）
上記Ｒ１、Ｒ２としては、例えば、下記式群に示される芳香族残基を挙げることができる。 (However, in the above formula, R 1 is a divalent aromatic or aliphatic residue having 6 to 30 carbon atoms, and R 2 is a divalent aromatic residue having 6 to 30 carbon atoms. From the group consisting of an alkylene group having 2 to 20 carbon atoms, a cycloalkylene group having 2 to 20 carbon atoms, and a polydiorganosiloxane group chain-terminated with an alkylene group having 2 to 8 carbon atoms. It is a selected divalent organic group.)
Examples of R 1 and R 2 include aromatic residues represented by the following formula group.

Figure 0006926616
Figure 0006926616

本発明では、ポリエステルとの親和性、コスト、溶融成形性等の観点から、２，２−ビス［４−（２，３−ジカルボキシフェノキシ）フェニル］プロパン二無水物とｍ−フェニレンジアミン、またはｐ−フェニレンジアミンとの縮合物である、下記式で示される繰り返し単位を有するポリマーが好ましい。 In the present invention, from the viewpoint of affinity with polyester, cost, melt moldability, etc., 2,2-bis [4- (2,3-dicarboxyphenoxy) phenyl] propane dianhydride and m-phenylenediamine, or A polymer having a repeating unit represented by the following formula, which is a condensate with p-phenylenediamine, is preferable.

Figure 0006926616
Figure 0006926616

または or

Figure 0006926616
Figure 0006926616

（ｎは２以上の整数、好ましくは２０〜５０の整数である。）
このポリエーテルイミドは、“ウルテム”の商品名で、ＳＡＢＩＣイノベーティブプラスチック社より入手可能であり、「Ｕｌｔｅｍ（登録商標）１０００」、「Ｕｌｔｅｍ（登録商標）１０１０」、「Ｕｌｔｅｍ（登録商標）１０４０」、「Ｕｌｔｅｍ（登録商標）５０００」、「Ｕｌｔｅｍ（登録商標）６０００」および「Ｕｌｔｅｍ（登録商標）ＸＨ６０５０」シリーズや「Ｅｘｔｅｍ（登録商標） ＸＨ」および「Ｅｘｔｅｍ（登録商標） ＵＨ」の登録商標名等で知られているものである。 (N is an integer of 2 or more, preferably an integer of 20 to 50.)
This polyetherimide is available from SABIC Innovative Plastics under the trade name of "Ultem", and is "Ultem® 1000", "Ultem® 1010", "Ultem® 1040". , "Ultem® 5000", "Ultem® 6000" and "Ultem® XH6050" series and registered trademark names of "Extem® XH" and "Extem® UH" Etc. are known.

本発明の二軸配向積層ポリエステルフィルムは、少なくとも２層からなる二軸配向積層ポリエステルフィルムであり、表層を構成する少なくともＡ層とＢ層の２層を含んでおり、Ａ層とＢ層の間に他の層（Ｘ）が存在しても構わない。なお、Ａ層、Ｂ層、他の層（Ｘ）はいずれも、いわゆる共押出により構成される層である。好ましい態様としては、Ａ層｜Ｂ層の２層構成である。もうひとつの好ましい態様としては、Ａ層とＢ層の間に中間層（Ｃ層）を設け、Ｃ層には実質的に粒子を含有しない方法が例示される。また、少なくともいずれか片面あるいは両面にコーティング層を設けても構わないが、その場合においても、Ａ層やＢ層が「表層を構成する」ものとする。さらに、Ａ層厚みがＢ層厚みより大きいことを特徴とする。Ａ層厚みがＢ層厚みより大きいことが、後述するＢ層の積層厚み（ｔ（μｍ））と該層に添加される粒子の最大粒径（Ｄ（μｍ））の比（ｔ／Ｄ）を好ましい範囲に設定しやすい。 The biaxially oriented laminated polyester film of the present invention is a biaxially oriented laminated polyester film composed of at least two layers, and includes at least two layers, A layer and B layer, which constitute a surface layer, and is between the A layer and the B layer. There may be another layer (X) in. The layer A, the layer B, and the other layer (X) are all layers formed by so-called coextrusion. A preferred embodiment is a two-layer structure of A layer | B layer. As another preferred embodiment, a method in which an intermediate layer (C layer) is provided between the A layer and the B layer and the C layer contains substantially no particles is exemplified. Further, the coating layer may be provided on at least one side or both sides, but even in that case, the A layer and the B layer "constitute the surface layer". Further, the thickness of the A layer is larger than the thickness of the B layer. The fact that the thickness of the A layer is larger than the thickness of the B layer is the ratio (t / D) of the laminated thickness (t (μm)) of the B layer, which will be described later, to the maximum particle size (D (μm)) of the particles added to the layer. Is easy to set in a preferable range.

本発明の二軸配向積層ポリエステルフィルムは、フィルムの一方の表面（Ａ層表面）におけるＡＦＭによる基準面からのしきい値６０ｎｍにおける突起個数が１０個／５０μｍ２以下である。ＡＦＭによる基準面からのしきい値６０ｎｍにおける突起個数は８個／５０μｍ２以下が好ましく、５個／５０μｍ２以下がさらに好ましい。本願において、ＡＦＭによる基準面からのしきい値６０ｎｍにおける突起個数を満足する表面がＡ層であることが、磁気記録媒体、特に、バリウムフェライトなどの磁性粉を適用する高信頼性かつ高密度記録用磁気記録媒体の磁性面として使用する場合に磁性層表面の電磁変換特性の欠陥抑止やエラーレート低下の点で好ましい。また、離型・工程用として使用した場合にピンホールなどの欠陥の発生やＤＦＲ用での露光不良を抑制する点でも好ましい。 In the biaxially oriented laminated polyester film of the present invention, the number of protrusions on one surface (A layer surface) of the film at a threshold value of 60 nm from the reference plane by AFM is 10 pieces / 50 μm 2 or less. Number of projections in the threshold 60nm from the reference plane by AFM is preferably 8/50 [mu] m 2 or less, more preferably 5/50 [mu] m 2 or less. In the present application, the fact that the surface satisfying the number of protrusions at the threshold value of 60 nm from the reference plane by AFM is the A layer is a highly reliable and high-density recording to which a magnetic recording medium, particularly a magnetic powder such as barium ferrite is applied. When used as a magnetic surface of a magnetic recording medium for use, it is preferable in terms of suppressing defects in the electromagnetic conversion characteristics of the surface of the magnetic layer and reducing the error rate. It is also preferable in that it suppresses the occurrence of defects such as pinholes and exposure defects for DFR when used for mold removal and processes.

また、Ａ層表面において、波長９．６５μｍにおけるパワースペクトル密度が１，０００〜５０，０００ｎｍ３の範囲にある。パワースペクトル密度は、好ましくは２，０００〜４０，０００ｎｍ３であり、さらに好ましくは３，０００〜３５，０００ｎｍ３の範囲である。パワースペクトル密度（Ｐｏｗｅｒ Ｓｐｅｃｔｒａｌ Ｄｅｎｓｉｔｙ 以下ＰＳＤと言う）とは、表面粗さのプロファイルデータをフーリエ変換処理し周波数分析を行い、各波長での強度を算出するものである。本願では原子間力顕微鏡（ＡＦＭ）を用いて、測定視野１２５μｍ×１２５μｍでＰＳＤ計測を行い、波長９．６５μｍにあたる強度を求めた。本願においては、上記ＰＳＤを満足する表面がＡ層であることが磁性層表面の欠陥抑止の上で好ましく、ＰＳＤが本願の範囲内であると走行性と電磁変換特性が高いレベルで両立でき好ましい。また、離型・工程用として使用した場合に加工層表面の欠陥抑止の点でも好ましい。 Further, on the surface of the layer A, the power spectral density at a wavelength of 9.65 μm is in the range of 1,000 to 50,000 nm 3. Power spectral density is preferably 2,000～40,000Nm 3, still more preferably from 3,000~35,000nm 3. The power spectral density (hereinafter referred to as PSD) is a method in which profile data of surface roughness is subjected to Fourier transform processing and frequency analysis is performed to calculate the intensity at each wavelength. In the present application, PSD measurement was performed using an atomic force microscope (AFM) with a measurement field of view of 125 μm × 125 μm, and the intensity corresponding to a wavelength of 9.65 μm was determined. In the present application, it is preferable that the surface satisfying the PSD is the A layer in order to suppress defects on the surface of the magnetic layer, and when the PSD is within the range of the present application, both running performance and electromagnetic conversion characteristics can be compatible at a high level, which is preferable. .. It is also preferable in terms of suppressing defects on the surface of the processed layer when used for mold removal and processes.

本発明のＡ層表面のＡＦＭによる基準面からのしきい値６０ｎｍにおける突起個数およびＰＳＤの制御方法としては、Ａ、Ｂ各層に含有する粒子の粒子径および含有量、さらにはＡ層の厚み、さらに、後述する横（ＴＤ）方向の延伸方法などの製造条件によって制御することができる。Ａ層に含有せしめる粒子の粒径は０．０１〜０．１５μｍであることが好ましく、含有量は０．０２〜１質量％、かつ、Ａ層の厚みがＢ層に含まれる粒子の最大粒子径の７倍以上、好ましくは１０〜１５倍にすることが好ましい。特に、粒径が０．０１〜０．０５μｍの粒子を含有させる場合の含有量は０．１〜１質量％、好ましくは、０．１〜０．７質量％、さらに好ましくは０．２〜０．５質量％であり、粒径が０．０５μｍを超える粒子を含有させる場合は、０．０２〜０．３質量％であり、好ましくは０．０５〜０．２質量％である。Ｂ層に含有せしめる粒子の粒径および含有量は後述の通りである。 As a method for controlling the number of protrusions and PSD at a threshold value of 60 nm from the reference plane by AFM on the surface of the A layer of the present invention, the particle size and content of the particles contained in each of the A and B layers, and the thickness of the A layer. Further, it can be controlled by manufacturing conditions such as a stretching method in the lateral (TD) direction described later. The particle size of the particles contained in the A layer is preferably 0.01 to 0.15 μm, the content is 0.02 to 1% by mass, and the thickness of the A layer is the maximum particle of the particles contained in the B layer. It is preferably 7 times or more, preferably 10 to 15 times the diameter. In particular, when particles having a particle size of 0.01 to 0.05 μm are contained, the content is 0.1 to 1% by mass, preferably 0.1 to 0.7% by mass, and more preferably 0.2 to 0.2 to 0.7% by mass. When it is 0.5% by mass and contains particles having a particle size of more than 0.05 μm, it is 0.02 to 0.3% by mass, preferably 0.05 to 0.2% by mass. The particle size and content of the particles contained in the B layer are as described later.

また、本発明の二軸配向積層ポリエステルフィルムのＡ層に好ましく含有される粒子としては、単一分散する球形の粒子や一次径が１０〜３０ｎｍの凝集粒子が好ましく例示できる。 Further, as the particles preferably contained in the A layer of the biaxially oriented laminated polyester film of the present invention, spherical particles having a single dispersion and aggregated particles having a primary diameter of 10 to 30 nm can be preferably exemplified.

Ａ層表面の中心線表面粗さＲａは０．１〜３ｎｍであることが好ましい。より好ましくはＲａが０．１〜２ｎｍである。中心線表面粗さＲａが上記の下限値未満であると走行性や巻き取り性が不良となりやすく、上記の上限値を超えると該表面にバックコート層を設け磁気記録媒体とした場合に転写痕による電磁変換特性が低下しやすく、エラーレートが増加しやすい。また、離型・工程用として使用した場合にピンホールなどの欠陥の発生が起こりやすい。 The center line surface roughness Ra of the surface of the A layer is preferably 0.1 to 3 nm. More preferably, Ra is 0.1 to 2 nm. If the center line surface roughness Ra is less than the above lower limit value, the running property and the winding property are likely to be poor, and if it exceeds the above upper limit value, a transfer mark is provided when a back coat layer is provided on the surface and used as a magnetic recording medium. The electromagnetic conversion characteristics due to the above are likely to decrease, and the error rate is likely to increase. In addition, defects such as pinholes are likely to occur when used for mold removal and processes.

本発明の二軸配向積層ポリエステルフィルムのＢ層表面は、三次元粗さ計による基準面から高さ６０ｎｍ以上の突起密度（Ｍ６０）が１００個／ｍｍ２未満である。Ｍ６０の値は好ましくは、８０個／ｍｍ２未満であり、さらに好ましくは７０個／ｍｍ２未満である。突起密度（Ｍ６０）とは、高さ６０ｎｍ以上の突起密度であり、三次元粗さ計によって計測される値である。この値は、基準面から高さ６０ｎｍにスライスレベルを設け、そのスライスレベルにおける突起密度を計測することにより得られる。Ｂ層表面のＭ６０を本発明の範囲に制御することは、本発明の二軸配向積層ポリエステルフィルムを磁気記録媒体、特に、バリウムフェライトなどの磁性粉を適用する高信頼性かつ高密度記録用磁気記録媒体のバックコート面として使用する場合に、磁気テープ加工後に巻き取った場合の反対の磁性層表面への転写による電磁変換特性の欠陥抑止やエラーレート低下の点で好ましい。つまり、Ｍ６０が１００個／ｍｍ２を超えるとＢ層表面にバックコート層を設けた時に粗大突起を形成する割合が高くなり、ロール状の磁気記録媒体とした時に該表面の粗大突起が磁性面に転写する場合があり電磁変換特性が低下しやすく、エラーレートが増加しやすい。また、離型・工程用として使用した場合に加工層に転写してピンホールなどの欠陥の発生やＤＦＲ用では露光不良が発生することがある。 The surface of the B layer of the biaxially oriented laminated polyester film of the present invention has a protrusion density (M60) of 60 nm or more in height from the reference plane by a three-dimensional roughness meter of less than 100 pieces / mm 2. The value of M60 is preferably less than 80 pieces / mm 2 , and more preferably less than 70 pieces / mm 2. The protrusion density (M60) is a protrusion density having a height of 60 nm or more, and is a value measured by a three-dimensional roughness meter. This value is obtained by setting a slice level at a height of 60 nm from the reference plane and measuring the protrusion density at the slice level. Controlling the M60 on the surface of the B layer within the scope of the present invention means applying the biaxially oriented laminated polyester film of the present invention to a magnetic recording medium, particularly a magnetic powder such as barium ferrite, for highly reliable and high-density recording magnetism. When used as a backcoat surface of a recording medium, it is preferable in terms of suppressing defects in electromagnetic conversion characteristics and lowering the error rate due to transfer to the opposite magnetic layer surface when the magnetic tape is wound up. That is, when M60 exceeds 100 pieces / mm 2 , the ratio of forming coarse protrusions when the back coat layer is provided on the surface of the B layer increases, and when a roll-shaped magnetic recording medium is used, the coarse protrusions on the surface become magnetic surfaces. The electromagnetic conversion characteristics tend to decrease and the error rate tends to increase. Further, when it is used for mold removal / process, it may be transferred to a processed layer to cause defects such as pinholes, and for DFR, exposure defects may occur.

Ｍ６０の制御方法としては、Ｂ層に含有する粒子の粒径と含有量、Ｂ層厚み、ならびに後述の横（ＴＤ）方向の延伸方法などの製造方法によって制御が可能である。含有せしめる粒子の粒径は０．１０μｍ以上０．４０μｍ未満であることが好ましく、含有量は０．０５〜０．５質量％であることが好ましい。特に、粒径０．３μｍ以上の粒子の含有量は０．１５質量％以下、好ましくは０．１０質量％以下であり、粒径が０．３μｍ未満の粒子の含有量は０．１〜０．５質量％であることが好ましい。 The M60 can be controlled by a manufacturing method such as the particle size and content of the particles contained in the B layer, the thickness of the B layer, and the stretching method in the lateral (TD) direction described later. The particle size of the particles to be contained is preferably 0.10 μm or more and less than 0.40 μm, and the content is preferably 0.05 to 0.5% by mass. In particular, the content of particles having a particle size of 0.3 μm or more is 0.15% by mass or less, preferably 0.10% by mass or less, and the content of particles having a particle size of less than 0.3 μm is 0.1 to 0. It is preferably 5.5% by mass.

本発明の二軸配向積層ポリエステルフィルムのＢ層に好ましく含有される粒子としては特に限定されないが、無機粒子、有機粒子、いずれも用いることができる。２種類以上の粒子を併用することが本発明の特徴面を得るためには好ましい。具体的な種類としては、例えば、クレー、マイカ、酸化チタン、炭酸カルシウム、湿式シリカ、乾式シリカ、コロイダルシリカ、リン酸カルシウム、硫酸バリウム、アルミナ珪酸塩、カオリン、タルク、モンモリロナイト、アルミナ、ジルコニア等の無機粒子、アクリル酸類、スチレン系樹脂、シリコーン、イミド等を構成成分とする有機粒子、コアシェル型有機粒子などが例示できるが、本発明の突起密度とＰＳＤを制御するには、単一分散する球形の粒子である有機粒子やコロイダルシリカが特に好ましい。 The particles preferably contained in the B layer of the biaxially oriented laminated polyester film of the present invention are not particularly limited, but either inorganic particles or organic particles can be used. It is preferable to use two or more kinds of particles in combination in order to obtain the characteristic surface of the present invention. Specific types include inorganic particles such as clay, mica, titanium oxide, calcium carbonate, wet silica, dry silica, colloidal silica, calcium phosphate, barium sulfate, alumina silicate, kaolin, talc, montmorillonite, alumina, and zirconia. , Acrylic acids, styrene resins, silicones, imides, and other organic particles, core-shell type organic particles, etc. can be exemplified. However, in order to control the protrusion density and PSD of the present invention, single dispersed spherical particles Organic particles and colloidal silica are particularly preferable.

上記の粒子を含有するＢ層表面の中心線表面粗さＲａは３〜１５ｎｍであることが好ましい。また、１０点平均粗さＲｚは好ましくは６０〜２００ｎｍ、より好ましくは７０〜１８０ｎｍであり、さらに好ましくは８０〜１６０ｎｍである。より好ましくはＲａが５〜１２ｎｍ、Ｒｚが７０〜１５０ｎｍである。中心線表面粗さＲａおよびＲｚが上記の下限値未満であると走行性や巻き取り性が不良となりやすく、ＲａおよびＲｚが上記の上限値を超えると該表面にバックコート層を設け磁気記録媒体とした場合に転写痕による電磁変換特性が低下しやすく、エラーレートが増加しやすい。また、離型・工程用として使用した場合に加工層に転写してピンホールなどの欠陥の発生やＤＦＲ用では露光不良が発生することがある。 The center line surface roughness Ra of the surface of the B layer containing the above particles is preferably 3 to 15 nm. The 10-point average roughness Rz is preferably 60 to 200 nm, more preferably 70 to 180 nm, and even more preferably 80 to 160 nm. More preferably, Ra is 5 to 12 nm and Rz is 70 to 150 nm. If the center line surface roughness Ra and Rz are less than the above lower limit values, the running performance and the winding property are likely to be poor, and if Ra and Rz exceed the above upper limit values, a back coat layer is provided on the surface of the magnetic recording medium. In this case, the electromagnetic conversion characteristics due to the transfer marks are likely to decrease, and the error rate is likely to increase. Further, when it is used for mold removal / process, it may be transferred to a processed layer to cause defects such as pinholes, and for DFR, exposure defects may occur.

本発明の二軸配向積層ポリエステルフィルムのＢ層表面の突起密度は、高さ６０ｎｍのスライスレベルにおける突起密度（Ｍ６０（個／ｍｍ２））と基準面から高さ１０ｎｍのスライスレベルにおける突起密度（Ｍ１０（個／ｍｍ２））の関係が０．４＜（Ｍ６０／Ｍ１０）×１００＜５である。好ましくは（Ｍ６０／Ｍ１０）×１００の値は０．５〜３であり、さらに好ましくは０．５〜２．５である。下限値は小さければ小さい方が転写の抑制につながり好ましい。この値が５以上になると、基準面から高さ６０ｎｍ以上の突起割合が高くなり、転写が発生しやすくなり電磁変換特性が低下したり、エラーレートが増加したりしやすい。また、離型・工程用として使用した場合に加工層に転写してピンホールなどの欠陥の発生やＤＦＲ用では露光不良が発生することがある。 The protrusion density on the surface of the B layer of the biaxially oriented laminated polyester film of the present invention is the protrusion density (M60 (pieces / mm 2 )) at the slice level at a height of 60 nm and the protrusion density at the slice level at a height of 10 nm from the reference plane (M60 (pieces / mm 2)). The relationship of M10 (pieces / mm 2 )) is 0.4 <(M60 / M10) × 100 <5. The value of (M60 / M10) × 100 is preferably 0.5 to 3, and more preferably 0.5 to 2.5. The smaller the lower limit value, the more preferable it is because it leads to the suppression of transcription. When this value is 5 or more, the proportion of protrusions having a height of 60 nm or more from the reference plane becomes high, transfer is likely to occur, electromagnetic conversion characteristics are likely to be lowered, and the error rate is likely to increase. Further, when it is used for mold removal / process, it may be transferred to a processed layer to cause defects such as pinholes, and for DFR, exposure defects may occur.

上記した密度比（Ｍ６０／Ｍ１０）×１００の値の制御方法としては、Ｂ層中に少なくとも２種類以上の粒子径の異なる粒子（ＬおよびＭ、Ｓ）を併用することが好ましく、粒子（Ｌ）と粒子（Ｍ）、（Ｓ）の含有量で制御が可能である。なお、粒子（Ｌ）は粒子径が０．３〜０．４μｍであり、粒子（Ｍ）の粒子径は０．１０μｍ以上０．３μｍ未満である。この時、粒子（Ｌ）は粒子（Ｍ）よりも粒子径が大きい粒子である。粒子（Ｌ）の含有量は０．１５質量％以下であり、粒子（Ｍ）の含有量は０．１〜０．５質量％が好ましい。さらに、また、粒子（Ｍ）よりも小さく、粒子径が０．０５μｍ以上０．１５μｍ未満の粒子（Ｓ）を添加する場合は、含有量を０．１５〜０．３質量％の範囲とすることによって、本発明の突起密度（Ｍ６０）を増加させずに突起密度（Ｍ１０）が効率よく増加するため巻取り性が向上することがあり好ましい。 As a method for controlling the value of the density ratio (M60 / M10) × 100 described above, it is preferable to use at least two kinds of particles (L and M, S) having different particle diameters in combination in the B layer, and the particles (L). ) And the contents of the particles (M) and (S) can be controlled. The particle size of the particle (L) is 0.3 to 0.4 μm, and the particle size of the particle (M) is 0.10 μm or more and less than 0.3 μm. At this time, the particle (L) is a particle having a larger particle size than the particle (M). The content of the particles (L) is 0.15% by mass or less, and the content of the particles (M) is preferably 0.1 to 0.5% by mass. Furthermore, when particles (S) smaller than the particles (M) and having a particle size of 0.05 μm or more and less than 0.15 μm are added, the content is in the range of 0.15 to 0.3% by mass. As a result, the protrusion density (M10) is efficiently increased without increasing the protrusion density (M60) of the present invention, which may improve the take-up property, which is preferable.

本発明の二軸配向積層ポリエステルフィルムのＢ層の積層厚み（ｔ（μｍ））が０．５〜２．０μｍであり、かつ、積層厚み（ｔ（μｍ））と該層に添加される粒子の最大粒径（Ｄ（μｍ））の比（ｔ／Ｄ）は５以上１０以下が好ましい。より好ましくは５以上７以下である。（ｔ／Ｄ）が５未満であると突起が急峻となり磁気記録媒体としたときに磁性面への転写が起こる場合があり、電磁変換特性が低下したり、エラーレートが増加したりすることがある。 The laminated thickness (t (μm)) of the B layer of the biaxially oriented laminated polyester film of the present invention is 0.5 to 2.0 μm, and the laminated thickness (t (μm)) and the particles added to the layer. The ratio (t / D) of the maximum particle size (D (μm)) of is preferably 5 or more and 10 or less. More preferably, it is 5 or more and 7 or less. If (t / D) is less than 5, the protrusions become steep and transfer to the magnetic surface may occur when the magnetic recording medium is used, which may reduce the electromagnetic conversion characteristics or increase the error rate. be.

本発明の二軸配向積層ポリエステルフィルムのＡ層の厚みは２〜４μｍであることが好ましい。Ａ層の厚みが２μｍを下回ると、Ｂ層に含有されている粒子の突き上げによりＡ層表面の平滑性が低下し、６０ｎｍ以上の突起が増加したり、ＰＳＤが大きくなりすぎ電磁変換特性が低下することがある。 The thickness of the A layer of the biaxially oriented laminated polyester film of the present invention is preferably 2 to 4 μm. When the thickness of the A layer is less than 2 μm, the smoothness of the surface of the A layer is lowered due to the thrusting of the particles contained in the B layer, the protrusions of 60 nm or more are increased, and the PSD becomes too large and the electromagnetic conversion characteristics are deteriorated. I have something to do.

本発明の二軸配向積層ポリエステルフィルムの厚み（全フィルム厚み）は３．５〜４．５μｍの範囲が好ましい。厚みが３．５μｍより小さくなると、剛性や寸法安定性が低下しテープの腰が不十分となり磁気記録媒体としたときに電磁変換特性が低下する傾向がある。また、Ｂ層表面突起による平滑面（Ａ面）側への突き上げを抑制しにくくなる。また、４．５μｍより大きいとテープ１巻あたりのテープ長さが短くなるため、磁気テープの小型化、高容量に対応し難い。厚みの調整方法としては、二軸配向ポリエステルフィルムの製膜の際のポリマーの溶融押出時におけるスクリューの吐出量を調整し、口金から未延伸フィルムの厚みを制御することによって二軸延伸後のフィルム厚みを調節することが可能となる。 The thickness (total film thickness) of the biaxially oriented laminated polyester film of the present invention is preferably in the range of 3.5 to 4.5 μm. If the thickness is smaller than 3.5 μm, the rigidity and dimensional stability are lowered, the tape is insufficiently stiff, and the electromagnetic conversion characteristics tend to be lowered when used as a magnetic recording medium. In addition, it becomes difficult to suppress the push-up toward the smooth surface (A surface) side by the B layer surface protrusion. Further, if it is larger than 4.5 μm, the tape length per roll of the tape becomes short, so that it is difficult to cope with the miniaturization and high capacity of the magnetic tape. As a method of adjusting the thickness, the discharge amount of the screw at the time of melt extrusion of the polymer during the film formation of the biaxially oriented polyester film is adjusted, and the thickness of the unstretched film is controlled from the base to control the film after biaxial stretching. The thickness can be adjusted.

本発明の二軸配向ポリエステルフィルムの厚みは、離型用や工程用、さらに光学部材用では加工性や取扱い性の点で１０μｍ以上２５０μｍ以下であることが好ましいことがある。フィルムの厚みが２５０μｍを超える場合、フィルムを構成するポリエステル自体でも光が吸収されるため、ＤＦＲ基材として使用する場合に露光性が低下したり、光学部材として使用した場合に透明性が低下したりすることがある。ポリエステルフィルムの厚みを上記範囲とすると、透明性や露光性、ハンドリング性、搬送性が良好となり、ＤＦＲ基材用や積層セラミックコンデンサー製造工程用、偏光板離型用などの離型・工程用フィルム、さらフレキシブルディスプレイの透明電極基板などの光学部材用フィルムとして好適に用いることができる。これら用途の場合、フィルム厚みは、より好ましくは１５μｍ以上１００μｍ以下、さらに好ましくは１５μｍ以上５０μｍ以下である。 The thickness of the biaxially oriented polyester film of the present invention is preferably 10 μm or more and 250 μm or less in terms of workability and handleability for mold release, process, and optical members. When the thickness of the film exceeds 250 μm, the polyester itself constituting the film also absorbs light, so that the exposure property is lowered when used as a DFR base material, and the transparency is lowered when used as an optical member. It may happen. When the thickness of the polyester film is within the above range, transparency, exposure, handleability, and transportability are improved, and a film for mold release / process such as for a DFR base material, a laminated ceramic capacitor manufacturing process, and a polarizing plate release. Further, it can be suitably used as a film for an optical member such as a transparent electrode substrate of a flexible display. For these applications, the film thickness is more preferably 15 μm or more and 100 μm or less, and even more preferably 15 μm or more and 50 μm or less.

Ｂ層表面の三次元表面粗さ計による、基準面から高さ１０ｎｍ以上の突起密度（Ｍ１０）は０．５万〜３万個／ｍｍ２であることが好ましい。より好ましくは、０．６万〜２．５万個／ｍｍ２である。突起密度（Ｍ１０）が０．５万個／ｍｍ２未満であると走行性や巻き取り性が低下しやすい。また、上限の３万個／ｍｍ２を超えると突起密度（Ｍ６０）も増加し、本願の範囲を満足できない場合がある。さらに、突起間隔が小さくなることで突起が密集し粗大突起を形成しやすくなるため、磁気記録媒体としたとき、磁性面への転写が発生し、磁性層表面の欠陥を招くため電磁変換特性が低下しやすい。また、離型・工程用として使用した場合に加工層に転写してピンホールなどの欠陥の発生やＤＦＲ用では露光不良が発生することがある。 The protrusion density (M10) having a height of 10 nm or more from the reference plane according to the three-dimensional surface roughness meter on the surface of the B layer is preferably 5,000 to 30,000 pieces / mm 2 . More preferably, it is 6,000 to 25,000 pieces / mm 2 . If the protrusion density (M10) is less than 5,000 pieces / mm 2 , the running property and the winding property tend to deteriorate. Further, if the upper limit of 30,000 pieces / mm 2 is exceeded, the protrusion density (M60) also increases, and the range of the present application may not be satisfied. Furthermore, as the distance between the protrusions becomes smaller, the protrusions become denser and it becomes easier to form coarse protrusions. Therefore, when the magnetic recording medium is used, transfer to the magnetic surface occurs, which causes defects on the surface of the magnetic layer, resulting in electromagnetic conversion characteristics. Easy to drop. Further, when it is used for mold removal / process, it may be transferred to a processed layer to cause defects such as pinholes, and for DFR, exposure defects may occur.

本発明の二軸配向積層ポリエステルフィルムは、幅方向の湿度膨張係数が０〜８ｐｐｍ／％ＲＨであることが好ましい。湿度膨張係数が８ｐｐｍ／％ＲＨ以下であると、磁気記録媒体用に用いた場合、湿度変化による変形が大きくならず、寸法安定性が低下しにくくなる。より好ましい上限は６．５ｐｐｍ／％ＲＨであり、さらに好ましくは６ｐｐｍ／％ＲＨである。湿度膨張係数は分子鎖の緊張度合いが影響する物性であり、後述するようにＴＤ延伸１とＴＤ延伸２の倍率比によって制御することができ、また、ＴＤ延伸トータルの倍率やＭＤ延伸倍率との比によっても制御が可能である。ＴＤ延伸１とＴＤ延伸２の倍率比（ＴＤ１／ＴＤ２）が大きいほど湿度膨張係数は小さくなる。また、ＴＤ延伸トータルの倍率が高いほど湿度膨張係数は小さくなる。 The biaxially oriented laminated polyester film of the present invention preferably has a humidity expansion coefficient in the width direction of 0 to 8 ppm /% RH. When the coefficient of thermal expansion is 8 ppm /% RH or less, when used for a magnetic recording medium, the deformation due to a change in humidity does not increase, and the dimensional stability is less likely to decrease. A more preferable upper limit is 6.5 ppm /% RH, and even more preferably 6 ppm /% RH. The coefficient of thermal expansion is a physical property that is affected by the degree of tension of the molecular chain, and can be controlled by the magnification ratio of TD stretching 1 and TD stretching 2 as described later. It can also be controlled by the ratio. The larger the magnification ratio (TD1 / TD2) of TD stretching 1 and TD stretching 2, the smaller the coefficient of thermal expansion. Further, the higher the total magnification of TD stretching, the smaller the coefficient of thermal expansion.

なお、本発明において、ＭＤとは二軸配向積層ポリエステルフィルムの長手方向（縦方向、縦延伸方向と平行な方向）を示し、ＴＤとは二軸配向積層ポリエステルフィルムの幅方向（横方向、フィルム面上において縦方向と直角な方向）を示す。 In the present invention, MD indicates the longitudinal direction of the biaxially oriented laminated polyester film (longitudinal direction, the direction parallel to the longitudinal stretching direction), and TD refers to the width direction (horizontal direction, film) of the biaxially oriented laminated polyester film. Indicates a direction perpendicular to the vertical direction on the surface).

本発明の二軸配向積層ポリエステルフィルムは、フィルムのＡ層とＢ層とを重ね合わせたときの空気漏れ指数が３，３００秒以下であることが好ましく、より好ましくは３，０００秒以下、さらに好ましくは２，７００秒以下である。空気漏れ指数が上記範囲内であると、フィルムの巻き取り性が良好となるので好ましい。 The biaxially oriented laminated polyester film of the present invention preferably has an air leakage index of 3,300 seconds or less, more preferably 3,000 seconds or less, and further preferably 3,000 seconds or less when the A layer and the B layer of the film are superposed. It is preferably 2,700 seconds or less. When the air leakage index is within the above range, the windability of the film is improved, which is preferable.

空気漏れ指数を制御するためには、Ｂ層には、平均粒径の異なる少なくとも２種類以上の粒子を含有させることが特に有効である。具体的には、平均粒径０．２μｍより大きく０．４μｍ以下の大粒子と０．０５μｍ以上０．２μｍ以下の小粒子を併用することが特に好ましい。 In order to control the air leakage index, it is particularly effective to include at least two or more kinds of particles having different average particle sizes in the B layer. Specifically, it is particularly preferable to use large particles having an average particle size of more than 0.2 μm and 0.4 μm or less and small particles having an average particle size of 0.05 μm or more and 0.2 μm or less in combination.

本発明の二軸配向積層ポリエステルフィルムは、幅方向のヤング率が７ＧＰａ以上であることが好ましく、７〜１０ＧＰａであることが幅方向の湿度膨張係数の制御の観点からより好ましい。幅方向のヤング率が上記範囲内であると、磁気記録媒体用に用いた場合に磁気記録媒体の記録再生時の環境変化による寸法安定性が良好となる傾向にある。幅方向のヤング率は後述するＴＤ延伸１、２および３の温度や倍率によって制御することができる。特にトータルのＴＤ倍率が影響し、トータルのＴＤ倍率が高いほどＴＤヤング率が高くなる。 The biaxially oriented laminated polyester film of the present invention preferably has a Young's modulus in the width direction of 7 GPa or more, and more preferably 7 to 10 GPa from the viewpoint of controlling the coefficient of thermal expansion in the width direction. When the Young's modulus in the width direction is within the above range, the dimensional stability tends to be good due to environmental changes during recording and reproduction of the magnetic recording medium when used for a magnetic recording medium. Young's modulus in the width direction can be controlled by the temperature and magnification of TD stretching 1, 2 and 3 described later. In particular, the total TD magnification has an effect, and the higher the total TD magnification, the higher the TD Young's modulus.

本発明の二軸配向積層ポリエステルフィルムは、長手方向のヤング率が３．５〜８ＧＰａであることが好ましい。長手方向のヤング率が上記範囲内であると、磁気記録媒体用に用いた場合に磁気記録媒体の保管時の張力による保存安定性がより良好となる。長手方向のヤング率のさらに好ましい範囲は３．８〜７．５ＧＰａ、さらにより好ましい範囲は４〜７ＧＰａである。長手方向のヤング率はＭＤ延伸倍率で制御することができる。ＭＤ倍率が高いほどＭＤヤング率が高くなる。 The biaxially oriented laminated polyester film of the present invention preferably has a Young's modulus in the longitudinal direction of 3.5 to 8 GPa. When the Young's modulus in the longitudinal direction is within the above range, the storage stability due to the tension during storage of the magnetic recording medium becomes better when used for the magnetic recording medium. A more preferable range of Young's modulus in the longitudinal direction is 3.8 to 7.5 GPa, and an even more preferable range is 4 to 7 GPa. Young's modulus in the longitudinal direction can be controlled by the MD stretch ratio. The higher the MD magnification, the higher the MD Young's modulus.

本発明の二軸配向積層ポリエステルフィルムは、少なくとも２層からなる二軸配向積層ポリエステルフィルムであり、好ましい態様として２層構造、または、３層以上の積層構造が例示される。 The biaxially oriented laminated polyester film of the present invention is a biaxially oriented laminated polyester film composed of at least two layers, and a two-layer structure or a laminated structure of three or more layers is exemplified as a preferred embodiment.

本発明の二軸配向積層ポリエステルフィルムを磁気記録媒体用ベースフィルムとして用いる場合は、上記のＢ面側にバックコート層（以下ＢＣ層という）を設けることが高密度磁気記録媒体を得る上で好ましく、特に、磁性層に強磁性六方晶フェライト粉末を用いてなる磁気記録媒体は、磁性層および非磁性層やＢＣ層自体の厚みも薄いために、ＢＣ層の表面に支持体（Ｂ層）の表面突起の影響が出にくくなり平滑なＢＣ面が得られる。これにより、磁性面に転写痕を形成することなく超平坦な磁性表面を得ることが可能となるため優れた電磁変換特性を発揮できる。 When the biaxially oriented laminated polyester film of the present invention is used as a base film for a magnetic recording medium, it is preferable to provide a backcoat layer (hereinafter referred to as BC layer) on the B surface side in order to obtain a high-density magnetic recording medium. In particular, a magnetic recording medium using ferromagnetic hexagonal ferrite powder for the magnetic layer has a thin support (B layer) on the surface of the BC layer because the magnetic layer, the non-magnetic layer, and the BC layer itself are thin. A smooth BC surface can be obtained with less influence of surface protrusions. As a result, it is possible to obtain an ultra-flat magnetic surface without forming transfer marks on the magnetic surface, so that excellent electromagnetic conversion characteristics can be exhibited.

本発明の二軸配向積層ポリエステルフィルムを積層セラミックコンデンサー用製造工程フィルム（グリーンシート成形の支持体）や偏光板離型用フィルムとして用いる場合には、Ａ層/Ｘ層/Ｂ層の少なくとも３層積層構成とすることが好ましく、Ａ面（Ａ層）側に離型性を付与するためのコーティング層を設けることが好ましい。Ｂ面（Ｂ層）側の表面突起は高さや突起密度が制御されているため離型・工程用フィルムとして巻き上げた際に加工層に転写してピンホールなどの欠陥の発生が少ない離型・工程フィルムとなる。 When the biaxially oriented laminated polyester film of the present invention is used as a manufacturing process film for a laminated ceramic capacitor (support for forming a green sheet) or a film for separating a polarizing plate, at least three layers of A layer / X layer / B layer are used. It is preferable to have a laminated structure, and it is preferable to provide a coating layer for imparting mold releasability on the A surface (A layer) side. Since the height and protrusion density of the surface protrusions on the B surface (B layer) side are controlled, it is transferred to the processed layer when it is rolled up as a process film, and there are few defects such as pinholes. It becomes a process film.

本発明の二軸配向積層ポリエステルフィルムをドライフィルムレジスト（ＤＦＲ）基材やフレキシブルディスプレイの透明電極基板などの光学部材用フィルムとして用いる場合には、Ａ層/Ｘ層/Ｂ層の少なくとも３層積層構成とすることが好ましく、特に、Ｘ層は実質的に粒子を含有しない層とすることが特に好ましい。ＤＦＲ基材の場合は、Ａ面（Ａ層）側にレジスト層を設けることが好ましい。レジスト層に近い側のフィルム表面の光散乱が防止され、優れた透明性や露光不良の少ないＤＦＲ基材となる。また、フレキシブルディスプレイの透明電極基板などの光学部材用フィルムの場合は、粒子が含有される両表面層（Ａ層、Ｂ層）の平滑性が優れ、かつＸ層は実質的に無粒子層であるため優れた透明性が得られる。 When the biaxially oriented laminated polyester film of the present invention is used as a film for an optical member such as a dry film resist (DFR) base material or a transparent electrode substrate of a flexible display, at least three layers of A layer / X layer / B layer are laminated. The structure is preferable, and it is particularly preferable that the X layer is a layer that does not substantially contain particles. In the case of a DFR base material, it is preferable to provide a resist layer on the A side (A layer) side. Light scattering on the film surface near the resist layer is prevented, and the DFR substrate has excellent transparency and less exposure defects. Further, in the case of a film for an optical member such as a transparent electrode substrate of a flexible display, the smoothness of both surface layers (A layer and B layer) containing particles is excellent, and the X layer is a substantially particle-free layer. Therefore, excellent transparency can be obtained.

上記したような本発明の二軸配向積層ポリエステルフィルムは、たとえば次のように製造される。 The biaxially oriented laminated polyester film of the present invention as described above is produced, for example, as follows.

まず、ポリエステルのペレットを、押出機を用いて溶融し、口金から吐出した後、冷却固化してシート状に成形する。このとき、繊維焼結ステンレス金属フィルターによりポリマーを濾過することが、ポリマー中の未溶融物を除去するために好ましい。 First, polyester pellets are melted using an extruder, discharged from a mouthpiece, cooled and solidified, and formed into a sheet. At this time, it is preferable to filter the polymer with a fiber-sintered stainless metal filter in order to remove unmelted matter in the polymer.

本発明の特徴面を阻害しない範囲内であれば、各種添加剤、例えば、相溶化剤、可塑剤、耐候剤、酸化防止剤、熱安定剤、滑剤、帯電防止剤、増白剤、着色剤、導電剤、結晶核剤、紫外線吸収剤、難燃剤、難燃助剤、顔料、染料、などが添加されてもよい。 Various additives such as compatibilizers, plasticizers, weather resistant agents, antioxidants, heat stabilizers, lubricants, antistatic agents, whitening agents, and colorants, as long as they do not interfere with the characteristics of the present invention. , Conductive agents, crystal nucleating agents, ultraviolet absorbers, flame retardants, flame retardants, pigments, dyes, etc. may be added.

続いて、上記シートを長手方向と幅方向の二軸に延伸した後、熱処理する。上記のＡ層表面の６０ｎｍ以上の突起個数およびＰＳＤ、さらにＢ層表面の突起密度比（Ｍ６０／Ｍ１０）、幅方向の寸法安定性を向上させるために延伸工程は、縦方向の多段延伸および幅方向において２段階以上に分けることが好ましい。すなわち、横多段延伸によって突起密度が制御され、かつ、再横延伸により高寸法安定性の磁気テープとして最適な高強度のフィルムが得られ易いために好ましい。 Subsequently, the sheet is stretched biaxially in the longitudinal direction and the width direction, and then heat-treated. In order to improve the number of protrusions of 60 nm or more and PSD on the surface of the A layer, the protrusion density ratio (M60 / M10) on the surface of the B layer, and the dimensional stability in the width direction, the stretching step includes multi-step stretching in the longitudinal direction and width. It is preferable to divide the direction into two or more stages. That is, it is preferable because the protrusion density is controlled by the lateral multi-stage stretching, and the optimum high-strength film as a magnetic tape having high dimensional stability can be easily obtained by the re-lateral stretching.

延伸形式としては、長手方向に延伸した後に幅方向に２段階で延伸を行うなどの逐次二軸延伸法や同時二軸延伸した後にさらに幅方向に延伸する延伸方法が好ましい。 As the stretching type, a sequential biaxial stretching method such as stretching in the longitudinal direction and then stretching in two steps in the width direction, or a stretching method in which simultaneous biaxial stretching and then further stretching in the width direction are preferable.

以下、本発明のフィルムの製造方法について、ポリエチレンテレフタレート（ＰＥＴ）をポリエステルとして用いた例を代表例として説明する。なお本願はＰＥＴフィルムに限定されるものではなく、他のポリマーを用いたものものでもよい。例えば、ガラス転移温度や融点の高いポリエチレン−２，６−ナフタレンジカルボキシレートなどを用いてポリエステルフィルムを構成する場合は、以下に示す温度よりも高温で押出や延伸を行えばよい。 Hereinafter, the method for producing a film of the present invention will be described as a representative example in which polyethylene terephthalate (PET) is used as a polyester. The present application is not limited to the PET film, and may be one using another polymer. For example, when a polyester film is formed using polyethylene-2,6-naphthalenedicarboxylate having a high glass transition temperature or melting point, extrusion or stretching may be performed at a temperature higher than the temperatures shown below.

まず、ＰＥＴのペレットを製造する。ＰＥＴは、次のいずれかのプロセスで製造される。すなわち、（１）テレフタル酸とエチレングリコールを原料とし、直接エステル化反応によって低分子量のＰＥＴまたはオリゴマーを得、さらにその後の三酸化アンチモンやチタン化合物を触媒に用いた重縮合反応によってポリマーを得るプロセス、（２）ジメチルテレフタレートとエチレングリコールを原料とし、エステル交換反応によって低分子量体を得、さらにその後の三酸化アンチモンやチタン化合物を触媒に用いた重縮合反応によってポリマーを得るプロセスである。 First, PET pellets are produced. PET is manufactured by one of the following processes. That is, (1) a process in which terephthalic acid and ethylene glycol are used as raw materials, a low molecular weight PET or oligomer is obtained by a direct esterification reaction, and then a polymer is obtained by a polycondensation reaction using an antimony trioxide or a titanium compound as a catalyst. , (2) A process in which a low molecular weight substance is obtained by an ester exchange reaction using dimethyl terephthalate and ethylene glycol as raw materials, and then a polymer is obtained by a polycondensation reaction using an antimony trioxide or a titanium compound as a catalyst.

フィルムを構成するＰＥＴに粒子を含有させるには、エチレングリコールに粒子を所定割合にてスラリーの形で分散させ、このエチレングリコールを重合時に添加する方法が好ましい。粒子を添加する際には、例えば、粒子の合成時に得られる水ゾルやアルコールゾル状態の粒子を一旦乾燥させることなく添加すると粒子の分散性がよい。また、粒子の水スラリーを直接ＰＥＴペレットと混合し、ベント式二軸混練押出機を用いて、ＰＥＴに練り込む方法も有効である。粒子の含有量を調節する方法としては、上記方法で高濃度の粒子のマスターペレットを作っておき、それを製膜時に粒子を実質的に含有しないＰＥＴで希釈して粒子の含有量を調節する方法が有効である。この際、粒子を含有しないＰＥＴの固有粘度を粒子含有ペレットの固有粘度よりも高く調整しておくことは上記した突起密度（Ｍ６０）や突起密度比（Ｍ６０／Ｍ１０）×１００の値を制御する上で有効である。 In order to contain the particles in the PET constituting the film, it is preferable to disperse the particles in ethylene glycol in a predetermined ratio in the form of a slurry and add the ethylene glycol at the time of polymerization. When adding the particles, for example, if the particles in the water sol or alcohol sol state obtained during the synthesis of the particles are added without being dried once, the dispersibility of the particles is good. It is also effective to directly mix the aqueous slurry of particles with PET pellets and knead them into PET using a vent type twin-screw kneading extruder. As a method for adjusting the particle content, a master pellet of high-concentration particles is prepared by the above method, and the master pellet is diluted with PET which does not substantially contain particles at the time of film formation to adjust the particle content. The method is effective. At this time, adjusting the intrinsic viscosity of the PET containing no particles to be higher than the intrinsic viscosity of the pellets containing particles controls the above-mentioned values of the protrusion density (M60) and the protrusion density ratio (M60 / M10) × 100. Valid on.

次に、得られたＰＥＴのペレットを、１８０℃で３時間以上減圧乾燥した後、固有粘度が低下しないように窒素気流下あるいは減圧下で、２７０〜３２０℃に加熱された押出機に供給し、スリット状のダイから押出し、キャスティングロール上で冷却して未延伸フィルムを得る。この際、キャスト時のドラフト比（口金のスリット幅／未延伸フィルムの厚み）は、１０倍以上好ましくは１２倍以上の高い値で、Ｂ面側がキャスト面に接地するように行うことが本発明において得に有効である。高ドラフトキャストを行うと粒子が表層部へ集中しやすくなり、各Ａ、Ｂ層に含有した粒子の位置規制が可能となり、本発明の突起密度を効率よく制御できるため、走行性と電磁変換特性の両立が可能となる。 Next, the obtained PET pellets are dried under reduced pressure at 180 ° C. for 3 hours or more, and then supplied to an extruder heated to 270 to 320 ° C. under a nitrogen stream or under reduced pressure so that the intrinsic viscosity does not decrease. , Extruded from a slit-shaped die and cooled on a casting roll to obtain an unstretched film. At this time, the draft ratio at the time of casting (slit width of the base / thickness of the unstretched film) is as high as 10 times or more, preferably 12 times or more, and the present invention is performed so that the B surface side is in contact with the cast surface. It is particularly effective in. When high draft casting is performed, the particles are easily concentrated on the surface layer portion, the position of the particles contained in each of the A and B layers can be regulated, and the protrusion density of the present invention can be efficiently controlled. Can be compatible with each other.

また、異物や変質ポリマーを除去するために各種のフィルター、例えば、焼結金属、多孔性セラミック、サンド、金網などの素材からなるフィルターを用いることが好ましい。 Further, it is preferable to use various filters, for example, filters made of materials such as sintered metal, porous ceramics, sand, and wire mesh, in order to remove foreign substances and altered polymers.

また、定量供給性を向上させ、所望のｔ／Ｄを得るためにギアポンプを設けることは上記した特徴面を形成する上で極めて好ましい。フィルムを積層するには、２台以上の押出機およびマニホールドまたは合流ブロックを用いて、複数の異なるポリマーを溶融積層するとよい。 Further, it is extremely preferable to provide a gear pump in order to improve the quantitative supply property and obtain a desired t / D in order to form the above-mentioned characteristic surface. To laminate the films, a plurality of different polymers may be melt-laminated using two or more extruders and manifolds or merging blocks.

次に、このようにして得られた未延伸フィルムを、数本のロールの配置された縦延伸機を用いて、ロールの周速差を利用して縦方向に延伸し（ＭＤ延伸）、続いてステンターにより横延伸を三段階行う（ＴＤ延伸１、ＴＤ延伸２、ＴＤ延伸３）の二軸延伸方法について説明する。 Next, the unstretched film thus obtained is stretched in the longitudinal direction (MD stretching) using a longitudinal stretching machine in which several rolls are arranged, utilizing the difference in peripheral speeds of the rolls, followed by A biaxial stretching method in which lateral stretching is performed in three stages using a stenter (TD stretching 1, TD stretching 2, and TD stretching 3) will be described.

まず、未延伸フィルムをＭＤ延伸する。ＭＤ延伸の延伸温度は、用いるポリマーの種類によって異なるが、未延伸フィルムのガラス転移温度（Ｔｇ）を目安として決めることができる。Ｔｇ−１０〜Ｔｇ＋１５℃の範囲であることが好ましく、より好ましくはＴｇ℃〜Ｔｇ＋１０℃である。上記範囲より延伸温度が低い場合には、フィルム破れが多発して生産性が低下し、ＭＤ延伸後の三段階ＴＤ延伸で安定して延伸することが困難となることがある。ＭＤ延伸倍率は３．３〜６倍、好ましくは３．３〜５．５倍である。ＭＤ延伸は２段階以上の多段で実施することが本発明の突起径を制御するために有効である。その場合、１段目のＭＤ延伸倍率がトータルＭＤ延伸倍率の７５％以上、好ましくは８０％以上に設定することが好ましい。 First, the unstretched film is MD-stretched. The stretching temperature of MD stretching varies depending on the type of polymer used, but can be determined by using the glass transition temperature (Tg) of the unstretched film as a guide. It is preferably in the range of Tg-10 to Tg + 15 ° C, more preferably Tg ° C to Tg + 10 ° C. If the stretching temperature is lower than the above range, the film may be torn frequently and the productivity may be lowered, and it may be difficult to stably stretch the film by the three-step TD stretching after the MD stretching. The MD draw ratio is 3.3 to 6 times, preferably 3.3 to 5.5 times. It is effective to carry out MD stretching in multiple stages of two or more stages in order to control the protrusion diameter of the present invention. In that case, it is preferable that the MD stretching ratio of the first stage is set to 75% or more, preferably 80% or more of the total MD stretching ratio.

次に、ステンターを用いて、ＴＤ延伸を行う。本発明の突起密度を有するフィルムを効率よく形成させるためには、温度の異なるゾーンで三段階にＴＤ方向に延伸することが好ましい。まず、一段目の延伸（ＴＤ延伸１）の延伸倍率は、好ましくは３．２〜６．０倍であり、より好ましくは３．３〜５．８倍である。また、ＴＤ延伸１の延伸温度は好ましくは（ＭＤ延伸後のフィルムの冷結晶化温度（以下Ｔｃｃ．ＢＦという）−５℃）〜（Ｔｃｃ．ＢＦ＋５℃）の範囲であり、さらに好ましくは（Ｔｃｃ．ＢＦ−３℃）〜（Ｔｃｃ．ＢＦ＋５℃）の範囲で行う。 Next, TD stretching is performed using a stenter. In order to efficiently form the film having the protrusion density of the present invention, it is preferable to stretch the film in three stages in the TD direction in zones having different temperatures. First, the draw ratio of the first-stage stretching (TD stretching 1) is preferably 3.2 to 6.0 times, more preferably 3.3 to 5.8 times. The stretching temperature of TD stretching 1 is preferably in the range of (cold crystallization temperature of the film after MD stretching (hereinafter referred to as Tcc.BF) -5 ° C.) to (Tcc.BF + 5 ° C.), and more preferably (Tcc.BF + 5 ° C.). .BF-3 ° C) to (Tcc.BF + 5 ° C).

次にステンター内で二段目の延伸（ＴＤ延伸２）を行う。ＴＤ延伸２の延伸倍率は好ましくは１．２〜２倍であり、より好ましくは１．３〜１．８倍、さらに好ましくは１．３〜１．６倍である。ＴＤ延伸倍率比（ＴＤ延伸１）／（ＴＤ延伸２）を２〜３の範囲に設定することは上記の突起径や密度比を上記範囲内に設定する有効な手段である。ＴＤ延伸２の延伸温度は好ましくは（ＴＤ延伸１温度＋５０）〜（ＴＤ延伸１温度＋１００）℃の範囲であり、さらに好ましくは（ＴＤ延伸１温度＋６０）〜（ＴＤ延伸１温度＋９０）℃の範囲で行う。前工程の延伸温度よりも十分高めることにより、ＴＤ延伸２で発生するボイドが抑制されるため突起が高くなりすぎず、本発明の突起密度を特定の範囲内に制御することが可能となるため好ましい。 Next, the second stage stretching (TD stretching 2) is performed in the stenter. The draw ratio of TD stretch 2 is preferably 1.2 to 2 times, more preferably 1.3 to 1.8 times, still more preferably 1.3 to 1.6 times. Setting the TD stretching ratio (TD stretching 1) / (TD stretching 2) in the range of 2 to 3 is an effective means for setting the protrusion diameter and the density ratio within the above range. The stretching temperature of TD stretching 2 is preferably in the range of (TD stretching 1 temperature +50) to (TD stretching 1 temperature +100) ° C., and more preferably (TD stretching 1 temperature +60) to (TD stretching 1 temperature +90) ° C. Do it in the range. By sufficiently raising the stretching temperature in the previous step, the voids generated in the TD stretching 2 are suppressed, so that the protrusions do not become too high, and the protrusion density of the present invention can be controlled within a specific range. preferable.

続いて、この延伸フィルムを幅方向に微延伸（ＴＤ延伸３）しながら熱固定処理する。本発明の突起密度を制御するための熱固定処理条件として、温度は（ＴＤ延伸２温度＋５）〜（ＴＤ延伸２温度＋１５）℃で行い、ＴＤ延伸３の延伸倍率は好ましくは１．０５〜１．２倍であり、より好ましくは１．０５〜１．１５倍である。 Subsequently, the stretched film is heat-fixed while being slightly stretched in the width direction (TD stretching 3). As the heat fixing treatment condition for controlling the protrusion density of the present invention, the temperature is (TD stretching 2 temperature +5) to (TD stretching 2 temperature +15) ° C., and the stretching ratio of TD stretching 3 is preferably 1.05 to 5. It is 1.2 times, more preferably 1.05 to 1.15 times.

その後、緊張下または幅方向に弛緩しながら熱固定処理する。熱固定は２段階以上に分けて行うことが好ましい。熱処理（ＨＳ１）を（（ＴＤ延伸３温度））〜（ＴＤ延伸３温度＋１０）℃の範囲、２段目熱処理（ＨＳ２）を（（ＨＳ１）＋１０）〜（（ＨＳ１）＋２０）℃で行う。熱固定処理時間は５〜３０秒の範囲、弛緩率は０．３〜２％で行うのが好ましい。熱固定処理後は把持しているクリップを開放することでフィルムにかかる張力を低減させながら室温へ急冷する。その後、フィルムエッジを除去しロールに巻き取り、本発明の二軸配向積層ポリエステルフィルムを得ることができる。 Then, heat fixing treatment is performed while relaxing under tension or in the width direction. It is preferable that the heat fixing is performed in two or more stages. The heat treatment (HS1) is performed in the range of ((TD stretching 3 temperature)) to (TD stretching 3 temperature +10) ° C., and the second stage heat treatment (HS2) is performed in the range of ((HS1) +10) to ((HS1) +20) ° C. The heat fixing treatment time is preferably in the range of 5 to 30 seconds, and the relaxation rate is preferably 0.3 to 2%. After the heat fixing process, the clip is opened to quench the film to room temperature while reducing the tension applied to the film. Then, the film edge is removed and wound on a roll to obtain the biaxially oriented laminated polyester film of the present invention.

なお、ＴＤ延伸３において微延伸ながら熱固定して、その後に２段階で熱固定することでボーイング現象による収縮を抑制しながら表面突起高さを本発明の範囲に制御しやすくなるため好ましい。 It is preferable that the TD stretching 3 is heat-fixed while being slightly stretched and then heat-fixed in two steps because the height of the surface protrusions can be easily controlled within the range of the present invention while suppressing shrinkage due to the Boeing phenomenon.

次に、磁気記録媒体は例えば次のように製造される。 Next, the magnetic recording medium is manufactured as follows, for example.

上記のようにして得られた磁気記録媒体用支持体（二軸配向積層ポリエステルフィルム）を、たとえば０．１〜３ｍ幅にスリットし、速度２０〜３００ｍ／ｍｉｎ、張力５０〜３００Ｎ／ｍで搬送しながら、一方の面に非磁性塗料をエクストルージョンコーターにより厚み０．５〜１．５μｍ塗布し乾燥後、さらに磁性塗料を厚み０．１〜０．３μｍで塗布する。その後、磁性塗料および非磁性塗料が塗布された支持体を磁気配向させ、温度８０〜１３０℃で乾燥させる。次いで、反対側の面にバックコートを厚み０．３〜０．８μｍで塗布し、カレンダー処理した後、巻き取る。なお、カレンダー処理は、小型テストカレンダー装置（金属ロール、７段）を用い、温度７０〜１２０℃、線圧０．５〜５ｋＮ／ｃｍで行う。その後、６０〜８０℃にて２４〜７２時間エージング処理し、１２．６５ｍｍ幅にスリットし、パンケーキを作製する。次いで、このパンケーキから特定の長さ分をカセットに組み込んで、カセットテープ型磁気記録媒体とする。 The support for magnetic recording medium (biaxially oriented laminated polyester film) obtained as described above is slit into, for example, a width of 0.1 to 3 m and conveyed at a speed of 20 to 300 m / min and a tension of 50 to 300 N / m. At the same time, a non-magnetic paint is applied to one surface with an extraction coater to a thickness of 0.5 to 1.5 μm, and after drying, a magnetic paint is further applied to a thickness of 0.1 to 0.3 μm. Then, the support coated with the magnetic paint and the non-magnetic paint is magnetically oriented and dried at a temperature of 80 to 130 ° C. Next, a back coat is applied to the opposite surface to a thickness of 0.3 to 0.8 μm, calendared, and then wound up. The calendar processing is performed using a small test calendar device (metal roll, 7 steps) at a temperature of 70 to 120 ° C. and a linear pressure of 0.5 to 5 kN / cm. Then, the pancake is aged at 60 to 80 ° C. for 24 to 72 hours and slit to a width of 12.65 mm to prepare a pancake. Next, a specific length of the pancake is incorporated into a cassette to form a cassette tape type magnetic recording medium.

ここで、磁性塗料などの組成は例えば以下のような組成が挙げられる。 Here, examples of the composition of the magnetic paint and the like include the following compositions.

以下、単に「部」と記載されている場合は、「質量部」を意味する。 Hereinafter, when simply described as "parts", it means "parts by mass".

［磁性層形成塗液］
バリウムフェライト磁性粉末 １００部
〔板径：２０．５ｎｍ、板厚：７．６ｎｍ、板状比：２．７、Ｈｃ：１９１ｋＡ／ｍ（≒２４００Ｏｅ）飽和磁化：４４Ａｍ２／ｋｇ、ＢＥＴ比表面積：６０ｍ２／ｇ〕
ポリウレタン樹脂 １２部
質量平均分子量 １０，０００
スルホン酸官能基 ０．５ｍｅｑ／ｇ
α−アルミナ ＨＩＴ６０（住友化学社製） ８部
カーボンブラック ＃５５（旭カーボン社製）粒子サイズ０．０１５μｍ ０．５部
ステアリン酸 ０．５部
ブチルステアレート ２部
メチルエチルケトン １８０部
シクロヘキサノン １００部
［非磁性層形成用塗布液］
非磁性粉体 α酸化鉄 １００部
平均長軸長０．０９μｍ、ＢＥＴ法による比表面積 ５０ｍ２／ｇ
ｐＨ ７
ＤＢＰ吸油量 ２７〜３８ｍｌ／１００ｇ
表面処理層Ａｌ２Ｏ３ ８質量％
カーボンブラック ２５部
コンダクテックスＳＣ−Ｕ（コロンビアンカーボン社製）
塩化ビニル共重合体 ＭＲ１０４（日本ゼオン社製） １３部
ポリウレタン樹脂 ＵＲ８２００（東洋紡社製） ５部
フェニルホスホン酸 ３．５部
ブチルステアレート １部
磁気記録媒体は、例えば、データ記録用途、具体的にはコンピュータデータのバックアップ用途（例えばリニアテープ式の記録媒体（ＬＴＯ５、ＬＴＯ６、次世代ＬＴＯテープ（ＬＴＯ７、ＬＴＯ８））や映像などのデジタル画像の記録用途などに好適に用いることができる。 [Magnetic layer forming coating liquid]
100 parts of barium ferrite magnetic powder [plate diameter: 20.5 nm, plate thickness: 7.6 nm, plate ratio: 2.7, Hc: 191 kA / m (≈2400 Oe) saturation magnetization: 44 Am 2 / kg, BET specific surface area: 60m 2 / g]
Polyurethane resin 12 parts Mass average molecular weight 10,000
Sulfonic acid functional group 0.5 meq / g
α-Alumina HIT60 (manufactured by Sumitomo Chemical Co., Ltd.) 8 parts Carbon black # 55 (manufactured by Asahi Carbon Co., Ltd.) Particle size 0.015 μm 0.5 parts Stearic acid 0.5 parts Butanone stearate 2 parts Methyl ethyl ketone 180 parts Cyclohexanone 100 parts [Non- Coating liquid for forming magnetic layer]
Non-magnetic powder α iron oxide 100 parts Average major axis length 0.09 μm, specific surface area by BET method 50 m 2 / g
pH 7
DBP oil absorption 27-38ml / 100g
Surface treatment layer Al 2 O 3 8% by weight
Carbon Black 25 parts Conductex SC-U (manufactured by Colombian Carbon)
Vinyl chloride copolymer MR104 (manufactured by Nippon Zeon) 13 parts Polyurethane resin UR8200 (manufactured by Toyo Boseki) 5 parts Phenylphosphonic acid 3.5 parts Butyl stearate 1 part Magnetic recording media are, for example, data recording applications, specifically. Can be suitably used for backing up computer data (for example, linear tape type recording media (LTO5, LTO6, next-generation LTO tapes (LTO7, LTO8)), recording digital images such as video, and the like.

本発明の二軸配向積層ポリエステルフィルムが好適に用いられる塗布型デジタル記録方式の磁気記録媒体としては、例えば、磁性層がバリウムフェライト等の強磁性粉末をポリウレタン樹脂等のバインダーに均一に分散させて磁性塗液を作成し、その塗液を塗布して磁性層が形成された塗布型磁気記録媒体を例示することができる。 As a coating type digital recording type magnetic recording medium in which the biaxially oriented laminated polyester film of the present invention is preferably used, for example, the magnetic layer uniformly disperses ferromagnetic powder such as barium ferrite in a binder such as polyurethane resin. An example is a coating type magnetic recording medium in which a magnetic coating liquid is prepared and the coating liquid is applied to form a magnetic layer.

本発明の二軸配向積層ポリエステルフィルムは、光学フィルム、及びそれを用いた偏光板、液晶表示装置用の光学補償フィルム等の光学用フィルムとして用いることができる。近年の薄型軽量ノートパソコンや薄型の電子モバイルの開発に伴い、液晶表示装置用光学補償フィルムの薄膜化への要求が非常に厳しくなっており、特に透明性と走行性に優れた薄膜の光学フィルムとして好適に用いることができる。 The biaxially oriented laminated polyester film of the present invention can be used as an optical film, a polarizing plate using the same, an optical compensation film for a liquid crystal display device, or the like. With the recent development of thin and lightweight notebook computers and thin electronic mobiles, the demand for thinning optical compensation films for liquid crystal display devices has become extremely strict, and thin optical films with excellent transparency and running performance have become particularly strict. Can be suitably used as.

本発明の二軸配向積層ポリエステルフィルムはまた離型用フィルムとしても使用できる。離型用フィルムは、ポリエステルフィルムを基材として、離型性のある樹脂層、例えばシリコ−ン樹脂やエポキシ樹脂などを塗布し形成される。特に、グリーンシート製造用、液晶偏光板用離型用、液晶保護フィルム用離型用、フォトレジスト用、多層基板用などの各種離型用途として使用されている。ポリエステルフィルム中には、加工適性、例えば滑り性、巻き特性などを良くするために粒子を適量配合しフィルム表面に微細な突起を形成することが一般的であるが、近年の各種用途の精密化などに伴い、使用される離型フィルムについても表面欠点の無い平滑な表面性と走行性が要求されている。本発明の二軸配向ポリエステルフィルムは高精細な表面平滑性と走行性を有するため各種用途の離型用フィルムとして好適に用いることができる。 The biaxially oriented laminated polyester film of the present invention can also be used as a release film. The release film is formed by applying a releaseable resin layer such as a silicone resin or an epoxy resin to a polyester film as a base material. In particular, it is used for various types of mold removal applications such as for green sheet manufacturing, liquid crystal polarizing plate mold release, liquid crystal protective film mold release, photoresist, and multilayer substrate. In polyester film, it is common to mix an appropriate amount of particles in order to improve processability, such as slipperiness and winding characteristics, to form fine protrusions on the film surface, but in recent years, various applications have been refined. As a result, the release film used is also required to have smooth surface properties and runnability without surface defects. Since the biaxially oriented polyester film of the present invention has high-definition surface smoothness and runnability, it can be suitably used as a release film for various purposes.

（物性の測定方法ならびに効果の評価方法）
本発明における特性値の測定方法並びに効果の評価方法は次の通りである。 (Measurement method of physical properties and evaluation method of effect)
The method for measuring the characteristic value and the method for evaluating the effect in the present invention are as follows.

（１）突起密度（M60、M10）
小坂研究所製のｓｕｒｆ−ｃｏｒｄｅｒ ＥＴ−４０００Ａを用いて下記条件にて３次元表面粗さを測定し、その後、内蔵されている解析ソフトにて粒子解析（複数レベル）を実施した。測定条件は下記のとおりであり、スライスレベルを１０ｎｍの等間隔に設定し、各スライスレベルの突起密度を場所を変えて２０回測定し平均値をもって値とした。サンプルセットは、視野測定のＸ方向が二軸配向ポリエステルフィルムの幅方向になるように試料台にセットした。 (1) Protrusion density (M60, M10)
Three-dimensional surface roughness was measured using a surf-corder ET-4000A manufactured by Kosaka Laboratory under the following conditions, and then particle analysis (multiple levels) was performed using the built-in analysis software. The measurement conditions were as follows. The slice levels were set at equal intervals of 10 nm, the protrusion density of each slice level was measured 20 times at different locations, and the average value was used as the value. The sample set was set on the sample table so that the X direction of the visual field measurement was the width direction of the biaxially oriented polyester film.

（但し、Ｍ60：基準面から高さ６０ｎｍのスライスレベルにおける突起密度(個／ｍｍ２)、
Ｍ10：基準面から１０ｎｍのスライスレベルにおける突起密度(個／ｍｍ２)
装置：小坂研究所製“ｓｕｒｆ−ｃｏｒｄｅｒ ＥＴ−４０００Ａ”
解析ソフト：ｉ−Ｆａｃｅ ｍｏｄｅｌ ＴＤＡ３１ ver.2.2.0.4JSGIS
触針先端半径：０．２μｍ
測定視野 ：Ｘ方向：３８０μｍ ピッチ：１μｍ
Ｙ方向：２８０μｍ ピッチ：５μｍ
針圧 ：５０μＮ
測定速度 ：０．１ｍｍ／ｓ
カットオフ値：低域−０．８ｍｍ、高域−なし
レベリング ：全域
フィルター ：ガウシアンフィルタ（２Ｄ）
倍率 ：１０万倍
粒子解析（複数レベル）条件
出力内容設定：山粒子
ヒステリシス幅：５ｎｍ
スライスレベル等間隔：１０ｎｍ
（２）Ｂ面（Ｂ層表面）の表面性および中心線表面粗さＲａ、１０点平均粗さＲｚ
上記（１）に記載の装置を用いて、上記に記載の測定条件でＢ面側の３次元粗さを場所を変えて１０回測定しその平均値をそれぞれ中心線表面粗さＲａ、１０点平均粗さＲｚとした。 (However, M60: protrusion density (pieces / mm 2 ) at the slice level at a height of 60 nm from the reference plane,
M10: Projection density at slice level 10 nm from reference plane (pieces / mm 2 )
Equipment: "surf-corder ET-4000A" manufactured by Kosaka Research Institute
Analysis software: i-Face model TDA31 ver.2.2.0.4 JSGIS
Radius of stylus tip: 0.2 μm
Measurement field of view: X direction: 380 μm Pitch: 1 μm
Y direction: 280 μm Pitch: 5 μm
Stylus pressure: 50 μN
Measurement speed: 0.1 mm / s
Cutoff value: Low range-0.8mm, High range-None Leveling: Whole area filter: Gaussian filter (2D)
Magnification: 100,000 times Particle analysis (multiple levels) Condition Output content setting: Mountain particle Hysteresis width: 5 nm
Slice level equal spacing: 10 nm
(2) Surface roughness of surface B (surface of layer B) and center line surface roughness Ra, 10-point average roughness Rz
Using the device described in (1) above, the three-dimensional roughness on the B surface side was measured 10 times at different locations under the measurement conditions described above, and the average value was measured at the center line surface roughness Ra and 10 points, respectively. The average roughness Rz was used.

なお、表面性は下記基準にて判断し、Ｃを平滑性不良とした。 The surface property was judged according to the following criteria, and C was defined as poor smoothness.

ＡＡ：Ｒｚが１００ｎｍ以下、
Ａ ：Ｒｚが１００ｎｍを超え１５０ｎｍ以下、
Ｂ ：Ｒｚが１５０ｎｍを超え２００ｎｍ未満、
Ｃ ：Ｒｚが２００ｎｍ以上
（３）パワースペクトル密度（ＰＳＤ）
原子力顕微鏡（ＡＦＭ）を用いて、場所を変えて１０視野測定を行った。サンプルセットは、カンチレバーの走査方向に対して垂直方向（Ｙ軸方向）がサンプルフィルムの長手方向（長手方向とは、フィルムの製造工程においてフィルムが走行する方向）となるようにサンプルをピエゾにセットして測定する。得られた画像について、Ｏｆｆ−Ｌｉｎｅ機能のPower Spectral Densityにて波長９．６５μｍにおけるＹ軸方向（フィルムの長手方向）の１Ｄ ＰＳＤを求め、平均値をＰＳＤとした。 AA: Rz is 100 nm or less,
A: Rz exceeds 100 nm and 150 nm or less,
B: Rz is more than 150 nm and less than 200 nm,
C: Rz is 200 nm or more (3) Power spectral density (PSD)
Using an atomic force microscope (AFM), 10 field measurements were performed at different locations. In the sample set, the sample is set in the piezo so that the direction perpendicular to the scanning direction of the cantilever (Y-axis direction) is the longitudinal direction of the sample film (the longitudinal direction is the direction in which the film travels in the film manufacturing process). And measure. For the obtained image, 1D PSD in the Y-axis direction (longitudinal direction of the film) at a wavelength of 9.65 μm was obtained by Power Spectral Density of the Off-Line function, and the average value was defined as PSD.

測定装置 ：ＮａｎｏＳｃｏｐｅ （Ｒ）ＩＩＩａ version5.31R1
（Ｄｉｇｉｔａｌ Ｉｎｓｔｒｕｍｅｎｔｓ社製）
カンチレバー ：シリコン単結晶
走査モード ：タッピングモード
走査範囲 ：１２５μｍ□
走査速度 ：０．５Ｈｚ
Samples line ：２５６
Flatten Auto ：オーダー３
（４）−１ 中心線表面粗さＲａ、１０点平均粗さＲｚ
上記（３）に記載の装置を用いて、場所を変えて１０視野測定した。サンプルセットは、カンチレバーの走査方向に対して垂直方向（Ｙ軸方向）がサンプルフィルムの長手方向（長手方向とは、フィルムの製造工程においてフィルムが走行する方向）となるようにサンプルをピエゾにセットして測定する。得られた画像について、Off-Line機能のRoughness Analysisにて算出し、平均値をＲａ、Ｒｚを求めた。条件は上記（３）と同条件で実施した。 Measuring device: NanoScope (R) IIIa version5.31R1
(Manufactured by Digital Instruments)
Cantilever: Silicon single crystal Scanning mode: Tapping mode Scanning range: 125 μm □
Scanning speed: 0.5Hz
Samples line: 256
Flatten Auto: Order 3
(4) -1 Center line surface roughness Ra, 10-point average roughness Rz
Using the apparatus described in (3) above, 10 visual fields were measured at different locations. In the sample set, the sample is set in the piezo so that the direction perpendicular to the scanning direction of the cantilever (Y-axis direction) is the longitudinal direction of the sample film (the longitudinal direction is the direction in which the film travels in the film manufacturing process). And measure. The obtained image was calculated by Roughness Analysis of the Off-Line function, and the average values were Ra and Rz. The conditions were the same as in (3) above.

（４）−２ Ａ面（Ａ層表面）の基準面からのしきい値６０ｎｍにおける突起個数
上記（３）に記載の装置を用いて、走査範囲を５０μｍ□に変更して場所を変えて１０視野測定を行った。得られた画像について、Off-Line機能のParticle AnalysisにてThreshold heightを６０ｎｍとして算出し、平均値を基準面からのしきい値６０ｎｍにおける突起個数とした。 (4) -2 Number of protrusions on the A surface (A layer surface) at a threshold value of 60 nm from the reference surface Using the apparatus described in (3) above, the scanning range is changed to 50 μm □ and the location is changed. The visual field was measured. The obtained image was calculated with the Threshold height set to 60 nm by Particle Analysis of the Off-Line function, and the average value was taken as the number of protrusions at the threshold value of 60 nm from the reference plane.

（５）幅方向の湿度膨張係数、寸法安定性
フィルムの幅方向に対して、下記条件にて測定を行い、３回の測定結果の平均値を本発明における湿度膨張係数とした。 (5) Humidity expansion coefficient and dimensional stability in the width direction The measurement was performed under the following conditions in the width direction of the film, and the average value of the three measurement results was taken as the humidity expansion coefficient in the present invention.

測定装置：島津製作所製熱機械分析装置ＴＭＡ−５０（湿度発生器：アルバック理工製湿度雰囲気調節装置ＨＣ−１）
試料サイズ：フィルム長手方向１０ｍｍ×フィルム幅方向１２．６ｍｍ
荷重：０．５ｇ
測定回数：３回
測定温度：３０℃
測定湿度：４０％ＲＨで６時間保持し寸法を測定し時間４０分で８０％ＲＨまで昇湿し、８０％ＲＨで６時間保持したあと支持体幅方向の寸法変化量ΔＬ（ｍｍ）を測定する。次式から湿度膨張係数（ｐｐｍ／％ＲＨ）を算出した。 Measuring device: Thermomechanical analyzer TMA-50 manufactured by Shimadzu Corporation (humidity generator: humidity atmosphere controller HC-1 manufactured by ULVAC Riko)
Sample size: 10 mm in the longitudinal direction of the film x 12.6 mm in the width direction of the film
Load: 0.5g
Number of measurements: 3 Measurement temperature: 30 ° C
Measurement humidity: Hold at 40% RH for 6 hours, measure the dimensions, humidify to 80% RH in 40 minutes, hold at 80% RH for 6 hours, and then measure the amount of dimensional change ΔL (mm) in the width direction of the support. do. The coefficient of thermal expansion (ppm /% RH) was calculated from the following equation.

湿度膨張係数（ｐｐｍ／％ＲＨ）＝１０６×｛（ΔＬ／１２．６）／（８０−４０）｝
なお、寸法安定性は以下の判断基準とし、Ｃを寸法安定性不良と判断した。 Humidity expansion coefficient (ppm /% RH) = 10 6 × {(ΔL / 12.6) / (80-40)}
The dimensional stability was used as the following criteria, and C was judged to be poor dimensional stability.

ＡＡ：湿度膨張係数が５．５ｐｐｍ／％以下
Ａ ：湿度膨張係数が５．５ｐｐｍ／％を超え６．０ｐｐｍ／％以下
Ｂ：湿度膨張係数が６．０ｐｐｍ／％を超え６．５ｐｐｍ／％未満
Ｃ：湿度膨張係数が６．５ｐｐｍ／％以上
（６）全フィルム厚み
以下の条件にて断面観察を場所を変えて１０視野行い、得られたフィルム厚み［μｍ］の平均値を算出し全フィルム厚み［μｍ］とした。 AA: Humidity expansion coefficient is 5.5 ppm /% or less A: Humidity expansion coefficient is more than 5.5 ppm /% and 6.0 ppm /% or less B: Humidity expansion coefficient is more than 6.0 ppm /% and less than 6.5 ppm /% C: Humidity expansion coefficient is 6.5 ppm /% or more (6) Total film thickness Under the following conditions, cross-sectional observation is performed in 10 different places, and the average value of the obtained film thickness [μm] is calculated to calculate the total film thickness. The thickness was [μm].

測定装置：透過型電子顕微鏡（ＴＥＭ） 日立製Ｈ−７１００ＦＡ型
測定条件：加速電圧 １００ｋＶ
測定倍率：１万倍
試料調整：超薄膜切片法（ＲｕＯ４染色）
観察面 ：ＴＤ−ＺＤ断面（ＴＤ：幅方向、ＺＤ：厚み方向）
測定回数：＜全厚み＞１視野につき３点、１０視野を測定する。 Measuring device: Transmission electron microscope (TEM) Hitachi H-7100FA type Measuring conditions: Acceleration voltage 100 kV
Measurement magnification: 10,000 times Sample preparation: ultrathin sectioning method (RuO 4 staining)
Observation surface: TD-ZD cross section (TD: width direction, ZD: thickness direction)
Number of measurements: <Total thickness> Measure 3 points and 10 fields of view per field of view.

（７）Ａ層（またはＢ層）の厚み
２次イオン質量分析装置（ＳＩＭＳ）を用いて、Ａ層側（またはＢ層側）の表面から深さ４，０００ｎｍの範囲のフィルム中の粒子のうち最も高濃度の粒子に起因する元素とポリエステルの炭素元素の濃度比（Ｍ＋／Ｃ＋）を粒子濃度とし、表面から深さ４，０００ｎｍまで厚さ方向の分析を行う。表層では表面という界面のために粒子濃度は低く表面から遠ざかるにつれて粒子濃度は高くなる。本発明のフィルムの場合は一旦極大値となった粒子濃度がまた減少し始める。この濃度分布曲線をもとに表層粒子濃度が極大値の１／２となる深さ（この深さは極大値となる深さよりも深い）を求め、これをＡ層（またはＢ層）の厚さとした。条件は次の通りである。 (7) Thickness of A layer (or B layer) Using a secondary ion mass spectrometer (SIMS), particles in a film having a depth of 4,000 nm from the surface on the A layer side (or B layer side) The concentration ratio (M + / C + ) of the element caused by the highest concentration of particles to the carbon element of polyester is used as the particle concentration, and analysis is performed in the thickness direction from the surface to a depth of 4,000 nm. In the surface layer, the particle concentration is low due to the interface of the surface, and the particle concentration increases as the distance from the surface increases. In the case of the film of the present invention, the particle concentration once reached the maximum value starts to decrease again. Based on this concentration distribution curve, the depth at which the surface particle concentration becomes 1/2 of the maximum value (this depth is deeper than the maximum value) is obtained, and this is the thickness of the A layer (or B layer). I made it. The conditions are as follows.

(1) 測定装置
２次イオン質量分析装置（ＳＩＭＳ）
***、ATOMIKA社製 A-DIDA3000
(2) 測定条件
１次イオン種 ：Ｏ２ ＋
１次イオン加速電圧：１２ｋＶ
１次イオン電流 ：２００ｎＡ
ラスター領域 ：４００μｍ□
分析領域 ：ゲート３０％
測定真空度 ：５．０×１０−９Torr
Ｅ−ＧＵＮ ：０．５ｋＶ−３．０Ａ
なお、表層から深さ４，０００ｎｍの範囲において粒子濃度の極大値が存在しない場合は、反対面から同様に測定し、反対面の厚みを求めて、全厚みからＡ層またはＢ層厚みを引いた値をとる。さらにまた、表層から深さ４，０００ｎｍの範囲に最も多く含有する粒子が有機高分子粒子の場合はＳＩＭＳでは測定が難しいので、表面からエッチングしながらＸＰＳ（Ｘ線光電子分光法）、ＩＲ（赤外分光法）などで上記同様のデプスプロファイルを測定し厚みを求めてもよいし、透過型電子顕微鏡（日立製Ｈ−６００型）を用いて、加速電圧１００ｋＶで、フィルム断面を、超薄切片法（ＲｕＯ４染色）で観察し、その界面をとらえ、その厚さを求めることもできる（上記記載順の優先順位により測定を行い、最初に測定できた測定値を当該層の厚みとする）。倍率は、測定したい厚さのレンジによって選択すればよく、特に限定されないが、１万〜１０万倍が適当である。 (1) Measuring device Secondary ion mass spectrometer (SIMS)
West Germany, ATOMIKA A-DIDA3000
(2) Measurement conditions Primary ion species: O 2 +
Primary ion acceleration voltage: 12 kV
Primary ion current: 200 nA
Raster area: 400 μm □
Analysis area: Gate 30%
Measurement vacuum: 5.0 × 10-9 Torr
E-GUN: 0.5kV-3.0A
If there is no maximum particle concentration in the range from the surface layer to a depth of 4,000 nm, the same measurement is performed from the opposite surface, the thickness of the opposite surface is obtained, and the thickness of the A layer or the B layer is subtracted from the total thickness. Take the value. Furthermore, if the particles contained most in the depth range of 4,000 nm from the surface layer are organic polymer particles, it is difficult to measure with SIMS, so XPS (X-ray photoelectron spectroscopy), IR (red) while etching from the surface. The same depth profile as described above may be measured by external spectroscopy) or the like to determine the thickness, or a transmission electron microscope (Hitachi H-600 type) may be used to obtain an ultrathin section of the film cross section at an acceleration voltage of 100 kV. It is also possible to observe by the method (RuO 4 staining), grasp the interface, and determine the thickness (measurement is performed according to the order of priority described above, and the first measured value is the thickness of the layer). .. The magnification may be selected according to the range of the thickness to be measured, and is not particularly limited, but 10,000 to 100,000 times is appropriate.

（８）フィルム中の粒子の粒子径（ｄ）、Ｂ層の最大粒子径（Ｄ）
フィルム断面を透過型電子顕微鏡（ＴＥＭ）を用い、１万倍で観察する。この時、写真上で１ｃｍ以下の粒子が確認できた場合はＴＥＭ観察倍率を５万倍に変えて観察する。ＴＥＭの切片厚さは約１００ｎｍとし、場所を変えて１００視野測定し、写真に撮影された分散した粒子全てについて等価球相当径をもとめ、横軸に等価球相当径を、縦軸に粒子の個数として粒子の個数分布をプロットし、そのピーク値の等価球相当径を粒子の粒子径（ｄ）とした。ここで、１万倍で観察した写真上に凝集粒子が確認できた場合は上記プロットに含めない。フィルム中に粒子径の異なる２種類以上の粒子が存在する場合、上記等価球相当径の個数分布は２個以上のピークを有する分布となる。この場合は、それぞれのピーク値をそれぞれの粒子の粒子径とする。Ｂ層の最大粒子径は、上記（６）で求めたＢ層厚みの領域において、１万倍で観察した１００視野の写真において最大の粒子径を持つ粒子の粒子径をＢ層の最大粒子径（Ｄ）とする。 (8) Particle size (d) of particles in the film, maximum particle size (D) of layer B
The cross section of the film is observed at a magnification of 10,000 using a transmission electron microscope (TEM). At this time, if particles of 1 cm or less can be confirmed on the photograph, the TEM observation magnification is changed to 50,000 times for observation. The section thickness of the TEM is about 100 nm, 100 fields are measured at different locations, the equivalent sphere equivalent diameter is obtained for all the dispersed particles photographed, the horizontal axis is the equivalent sphere equivalent diameter, and the vertical axis is the particle. The number distribution of particles was plotted as the number of particles, and the equivalent sphere-equivalent diameter of the peak value was defined as the particle size (d) of the particles. Here, if aggregated particles can be confirmed on the photograph observed at 10,000 times, they are not included in the above plot. When two or more kinds of particles having different particle diameters are present in the film, the number distribution of the equivalent sphere equivalent diameter is a distribution having two or more peaks. In this case, each peak value is taken as the particle size of each particle. The maximum particle size of the B layer is the maximum particle size of the B layer, which is the particle size of the particles having the maximum particle size in the 100-field photograph observed at 10,000 times in the region of the B layer thickness obtained in (6) above. Let it be (D).

（９）粒子の含有量
フィルム原料であるポリエステルへの粒子配合量から計算し、表に記載した。 (9) Particle content Calculated from the particle content in polyester, which is a raw material for film, and listed in the table.

なお、以下の手法に従いフィルムを分析することにより算出することもできる。 It can also be calculated by analyzing the film according to the following method.

（９）−１ 粒子の元素分析
フィルムからポリエステルをプラズマ灰化処理法で除去し粒子を露出させる。処理条件はポリマは灰化されるが粒子は極力ダメージを受けない条件を選択する。その粒子を走査型電子顕微鏡（ＳＥＭ）で観察し、粒子画像をイメージアナライザーで処理する。上記（８）で求めた粒度分布に従い、ＳＥＭの倍率を３０，０００倍にして、観察箇所を変えて２０視野観察し、観察した全粒子についてエネルギー分散型Ｘ線分光法（ＥＤＸ）を用いて元素分析を実施し、粒子と元素の関係を明確にする。 (9) -1 Elemental analysis of particles The polyester is removed from the film by a plasma ashing treatment method to expose the particles. Select a treatment condition in which the polymer is incinerated but the particles are not damaged as much as possible. The particles are observed with a scanning electron microscope (SEM) and the particle images are processed with an image analyzer. According to the particle size distribution obtained in (8) above, the magnification of SEM was increased to 30,000 times, observation was performed in 20 fields at different observation points, and all the observed particles were observed using energy dispersive X-ray spectroscopy (EDX). Perform elemental analysis to clarify the relationship between particles and elements.

（９）−２ 粒子の含有量
各積層部の表面を片刃で削り取り、削れ粉１００ｇにｏ−クロロフェノールを加え、攪拌しながら１００℃で１時間をかけてポリマを溶解する。次いで日立製作所製分離用超遠心機４０Ｐ型にローターＲＰ３０を装備し、セル１個当りに上記溶解液３０ｃｃを注入した後徐々に３０，０００ｒｐｍにする。３０，０００ｒｐｍ到達６０分後に粒子の分離を終了する。次いで上澄液を除去し分離粒子を採取する。採取した該粒子に常温のｏ−クロロフェノールを加え、均一けん濁した後、超遠心分離操作を行う。この操作は後述の分離粒子を示差走査熱量測定装置（ＤＳＣ）を用いてポリマに相当する融解ピークが検出されなくなるまでくり返す。このようにして得た分離粒子を１２０℃で１６時間真空乾燥した後、質量を測定した値を粒子の総含有量とし、これに対する比率（質量％）をもって粒子の含有量とする。 (9) -2 Particle content The surface of each laminated portion is scraped off with a single blade, o-chlorophenol is added to 100 g of the shavings, and the polymer is dissolved at 100 ° C. for 1 hour with stirring. Next, the rotor RP30 is mounted on the ultracentrifuge 40P type for separation manufactured by Hitachi, Ltd., and after injecting 30 cc of the above solution into each cell, the speed is gradually increased to 30,000 rpm. Particle separation is completed 60 minutes after reaching 30,000 rpm. Then, the supernatant is removed and the separated particles are collected. O-Chlorophenol at room temperature is added to the collected particles to make them uniformly turbid, and then an ultracentrifugation operation is performed. This operation is repeated for the separated particles described later using a differential scanning calorimetry device (DSC) until the melting peak corresponding to the polymer is no longer detected. The separated particles thus obtained are vacuum-dried at 120 ° C. for 16 hours, and then the measured value is taken as the total content of the particles, and the ratio (% by mass) to this is taken as the content of the particles.

（１０）空気漏れ指数
（株）東洋精機製、デジベック平滑度試験機を用いて、２５℃、６５％ＲＨにて測定した。まず、Ａ層とＢ層とを重ね合わせたフィルム（５×５ｃｍ、下側のフィルムは中央部分を約１ｃｍ角切り抜く）を試料台上に静かに乗せ、１ｋｇ／ｃｍ２の荷重を加えて減圧到達度をＳＴＥＰ１：３８３ｍｍＨｇ、ＳＴＥＰ２：３８２ｍｍＨｇ、ＳＴＥＰ３：３８１ｍｍＨｇに設定する。減圧度がＳＴＥＰ１に到達すると真空ポンプは自動的に停止する。フィルム間を空気が通過して系内に流入するため、減圧度は低下し、ＳＥＴＰ１の減圧度を切ると自動的に時間計が作動しＳＴＥＰ３の減圧度を切ると時間計は停止する。この値を読み取りフィルムを換えて３０回測定しその平均を空気漏れ指数とした。但し、時間計が１，０００秒以下で停止した場合はごみ付着の可能性が大きいためデータには入れなかった。 (10) Air Leakage Index Measured at 25 ° C. and 65% RH using a Digibeck smoothness tester manufactured by Toyo Seiki Co., Ltd. First, gently place a film (5 x 5 cm, the lower film cuts out about 1 cm square at the center) on the sample table, and apply a load of 1 kg / cm 2 to reduce the pressure. The reach is set to STEP1: 383 mmHg, STEP2: 382 mmHg, and STEP3: 381 mmHg. When the degree of decompression reaches STEP 1, the vacuum pump automatically stops. Since air passes between the films and flows into the system, the decompression degree decreases. When the decompression degree of SETP1 is turned off, the time meter automatically operates, and when the decompression degree of STEP3 is turned off, the time meter stops. This value was measured 30 times by changing the reading film, and the average was taken as the air leakage index. However, if the time meter stopped in 1,000 seconds or less, there was a high possibility of dust adhering, so it was not included in the data.

（１１）フィルム巻き取り性
幅３００ｍｍのフィルムを、巻き取り速度２００ｍ／ｍｉｎで、張力一定条件で巻き取り、長さ６，０００ｍのロールとした。このロールを温度６０℃、湿度８０％の条件で７２時間保管後の外観を目視により観察し、以下の基準で判断し、Ｃを巻き取り性不良とした。 (11) Film Rewindability A film having a width of 300 mm was wound at a winding speed of 200 m / min under constant tension conditions to obtain a roll having a length of 6,000 m. The appearance of this roll after being stored for 72 hours under the conditions of a temperature of 60 ° C. and a humidity of 80% was visually observed and judged according to the following criteria, and C was regarded as a poor take-up property.

Ａ：しわ、または端面ずれが全く認められない
Ｂ：しわが２カ所未満、または端面ずれが１ｍｍ未満のもの
Ｃ：しわが２箇所以上、または１ｍｍ以上のは紙面ずれが認められるもの。 A: No wrinkles or end face deviation B: Wrinkles less than 2 places or end face deviation less than 1 mm C: Wrinkles 2 or more places or 1 mm or more have paper surface deviation.

（１２）エラーレート
１ｍ幅にスリットしたフィルムを、張力２００Ｎで搬送させ、支持体の一方の表面に以下の記載に従って磁性塗料および非磁性塗料を塗布し１２．６５ｍｍ幅にスリットし、パンケーキを作成する。 （以下、「部」とあるのは「質量部」を意味する。） (12) Error rate A film slit to a width of 1 m is conveyed with a tension of 200 N, magnetic paint and non-magnetic paint are applied to one surface of the support according to the following description, slit to a width of 12.65 mm, and pancakes are made. create. (Hereinafter, "part" means "mass part".)

磁性層形成用塗布液
バリウムフェライト磁性粉末 １００部
（板径：２０．５ｎｍ、板厚：７．６ｎｍ、
板状比：２．７、Ｈｃ：１９１ｋＡ／ｍ（≒２４００Ｏｅ）
飽和磁化：４４Ａｍ２／ｋｇ、ＢＥＴ比表面積：６０ｍ２／ｇ）
ポリウレタン樹脂 １２部
質量平均分子量 １０，０００
スルホン酸官能基 ０．５ｍｅｑ／ｇ
α−アルミナ ＨＩＴ６０（住友化学社製） ８部
カーボンブラック ＃５５（旭カーボン社製）
粒子サイズ０．０１５μｍ ０．５部
ステアリン酸 ０．５部
ブチルステアレート ２部
メチルエチルケトン １８０部
シクロヘキサノン １００部
非磁性層形成用塗布液
非磁性粉体 α酸化鉄 ８５部
平均長軸長０．０９μｍ、ＢＥＴ法による比表面積 ５０ｍ２／ｇ
ｐＨ ７
ＤＢＰ吸油量 ２７〜３８ｍｌ／１００ｇ
表面処理層Ａｌ２Ｏ３ ８質量％
カーボンブラック １５部
“コンダクテックス”（登録商標）ＳＣ−Ｕ（コロンビアンカーボン社製）
ポリウレタン樹脂 ＵＲ８２００（東洋紡社製） ２２部
フェニルホスホン酸 ３部
シクロヘキサノン １４０部
メチルエチルケトン １７０部
ブチルステアレート １部
ステアリン酸 ２部
メチルエチルケトン ２０５部
シクロヘキサノン １３５部
上記の塗布液のそれぞれについて、各成分をニーダで混練した。１．０ｍｍφのジルコニアビーズを分散部の容積に対し６５体積％充填する量を入れた横型サンドミルに、塗布液をポンプで通液し、２，０００ｒｐｍで１２０分間（実質的に分散部に滞留した時間）、分散させた。得られた分散液にポリイソシアネートを非磁性層の塗料には５．０部、磁性層の塗料には２．５部を加え、さらにメチルエチルケトン３部を加え、１μｍの平均孔径を有するフィルターを用いて濾過し、非磁性層形成用および磁性層形成用の塗布液をそれぞれ調製した。 Coating liquid for forming a magnetic layer 100 parts of barium ferrite magnetic powder (plate diameter: 20.5 nm, plate thickness: 7.6 nm,
Plate ratio: 2.7, Hc: 191 kA / m (≈2400 Oe)
Saturation magnetization: 44Am 2 / kg, BET specific surface area: 60m 2 / g)
Polyurethane resin 12 parts Mass average molecular weight 10,000
Sulfonic acid functional group 0.5 meq / g
α-Alumina HIT60 (manufactured by Sumitomo Chemical Co., Ltd.) 8 parts Carbon Black # 55 (manufactured by Asahi Carbon Co., Ltd.)
Particle size 0.015 μm 0.5 part Stearic acid 0.5 part Butanone 2 parts Methyl ethyl ketone 180 parts Cyclohexanone 100 parts Non-magnetic layer forming coating liquid Non-magnetic powder α Iron oxide 85 parts Average major axis length 0.09 μm, Specific surface area 50 m 2 / g by BET method
pH 7
DBP oil absorption 27-38ml / 100g
Surface treatment layer Al 2 O 3 8% by weight
Carbon Black 15 copies "Conductex" (registered trademark) SC-U (manufactured by Colombian Carbon)
Polyurethane resin UR8200 (manufactured by Toyobo Co., Ltd.) 22 parts phenylphosphonic acid 3 parts cyclohexanone 140 parts methyl ethyl ketone 170 parts butyl stearate 1 part stearic acid 2 parts methyl ethyl ketone 205 parts cyclohexanone 135 parts For each of the above coating solutions, knead each component with a kneader. bottom. The coating liquid was pumped through a horizontal sand mill containing an amount of 1.0 mmφ zirconia beads filled in an amount of 65% by volume based on the volume of the dispersion portion, and stayed at 2,000 rpm for 120 minutes (substantially staying in the dispersion portion). Time), dispersed. To the obtained dispersion, 5.0 parts of polyisocyanate was added to the paint of the non-magnetic layer, 2.5 parts was added to the paint of the magnetic layer, and 3 parts of methyl ethyl ketone was further added, and a filter having an average pore size of 1 μm was used. And filtered to prepare coating liquids for forming a non-magnetic layer and forming a magnetic layer, respectively.

得られた非磁性層形成用塗布液を、本発明の二軸延伸積層ポリエステルフィルム上に乾燥後の厚さが０．８μｍになるように塗布乾燥させた後、磁性層形成用塗布液を乾燥後の磁性層の厚さが０．０７μｍになるように塗布を行い、磁性層がまだ湿潤状態にあるうちに６，０００Ｇ（６００ｍＴ）の磁力を持つコバルト磁石と６，０００Ｇ（６００ｍＴ）の磁力を持つソレノイドにより配向させ乾燥させた。その後、カレンダー後の厚みが０．５μｍとなるようにバックコート層（カーボンブラック 平均粒子サイズ：１７ｎｍ １００部、炭酸カルシウム平均粒子サイズ：４０ｎｍ ８０部、αアルミナ 平均粒子サイズ：２００ｎｍ ５部をポリウレタン樹脂、ポリイソシアネートに分散）を塗布した。次いでカレンダで温度９０℃、線圧３００ｋｇ／ｃｍ（２９４ｋＮ／ｍ）にてカレンダ処理を行った後、６５℃で、７２時間キュアリングした。さらに、スリット品の送り出し、巻き取り装置を持った装置に不織布とカミソリブレードが磁性面に押し当たるように取り付け、テープクリーニング装置で磁性層の表面のクリーニングを行い、磁気テープ原反を得た。 The obtained coating liquid for forming a non-magnetic layer is applied and dried on the biaxially stretched laminated polyester film of the present invention so that the thickness after drying is 0.8 μm, and then the coating liquid for forming a magnetic layer is dried. The coating was applied so that the thickness of the subsequent magnetic layer was 0.07 μm, and while the magnetic layer was still wet, a cobalt magnet having a magnetic force of 6,000 G (600 mT) and a magnetic force of 6,000 G (600 mT). It was oriented and dried by a solenoid with. After that, the backcoat layer (carbon black average particle size: 17 nm 100 parts, calcium carbonate average particle size: 40 nm 80 parts, α-alumina average particle size: 200 nm 5 parts is made of polyurethane resin so that the thickness after the calendar becomes 0.5 μm. , Dispersed in polyisocyanate) was applied. Next, the calendar was subjected to a calendar treatment at a temperature of 90 ° C. and a linear pressure of 300 kg / cm (294 kN / m), and then cured at 65 ° C. for 72 hours. Further, the non-woven fabric and the razor blade were attached to a device having a slit product feeding and winding device so as to be pressed against the magnetic surface, and the surface of the magnetic layer was cleaned with a tape cleaning device to obtain a magnetic tape original fabric.

得られたテープ原反を１２．６５ｍｍ（１／２インチ）幅にスリットし、それをＬＴＯ用のケースに組み込み、磁気記録テープの長さが９６０ｍのデータストレージカートリッジを作成した。このデータストレージを、ＩＢＭ社製ＬＴＯ６ドライブを用いて２３℃５０％ＲＨの環境で記録し（記録波長０．５５μｍ）、次に、カートリッジを５０℃、８０％ＲＨ環境下に７日間保存した。カートリッジを１日常温に保存した後、全長の再生を行い、再生時の信号のエラーレートを測定した。エラーレートはドライブから出力されるエラー情報（エラービット数）から次式にて算出する。次の基準で寸法安定性を評価する。
エラーレート＝（エラービット数）／（書き込みビット数）
ＡＡ：エラーレートが１．０×１０−６未満
Ａ：エラーレートが１．０×１０−６以上、１．０×１０−５未満
Ｂ：エラーレートが１．０×１０−５以上、１．０×１０−４未満
Ｃ：エラーレートが１．０×１０−４以上
（１３）レジスト特性評価
以下ａ．からｃ．の方法により評価を行う。
ａ．片面鏡面研磨した６インチＳｉウエハー上に、東京応化（株）製のネガレジスト“ＰＭＥＲＮ−ＨＣ６００”を塗布し、大型スピナーで回転させることによって厚み７μｍのレジスト層を作製する。次いで、窒素循環の通風オーブンを用いて７０℃の温度条件で約２０分間の前熱処理を行う。
ｂ．ポリエステルフィルムのＢ面をレジスト層と接触するように重ね、ゴム製のローラーを用いて、レジスト層上にポリエステルフィルムをラミネートし、その上に、クロム金属でパターニングされたレチクルを配置し、そのレクチル上からＩ線（波長３６５ｎｍにピークをもつ紫外線）ステッパーを用いて露光を行う。
ｃ．レジスト層からポリエステルフィルムを剥離した後、現像液Ｎ−Ａ５が入った容器にレジスト層を入れ約１分間の現像を行う。その後、現像液から取り出し、水で約１分間の洗浄を行う。現像後に作成されたレジストパターンのＬ／Ｓ（μｍ）（Ｌｉｎｅ ａｎｄ Ｓｐａｃｅ）＝１０／１０μｍの３０本の状態を走査型電子顕微鏡ＳＥＭを用いて約８００〜３０００倍率で観察し、パターンに欠けのある本数で以下のように評価する。 The obtained original tape was slit to a width of 12.65 mm (1/2 inch) and incorporated into a case for LTO to prepare a data storage cartridge having a magnetic recording tape length of 960 m. This data storage was recorded using an IBM LTO6 drive in an environment of 23 ° C. and 50% RH (recording wavelength 0.55 μm), and then the cartridges were stored in an environment of 50 ° C. and 80% RH for 7 days. After storing the cartridge at room temperature for one day, the full length was regenerated, and the error rate of the signal at the time of reproduction was measured. The error rate is calculated by the following formula from the error information (number of error bits) output from the drive. Dimensional stability is evaluated according to the following criteria.
Error rate = (number of error bits) / (number of write bits)
AA: Error rate less than 1.0 × 10-6 A: Error rate 1.0 × 10-6 or more, less than 1.0 × 10-5 B: Error rate 1.0 × 10-5 or more, 1 .0 × 10 -4 or less C: Error rate is 1.0 × 10 -4 or more (13) Resist characteristic evaluation or less a. To c. Evaluation is performed by the method of.
a. A negative resist "PMERN-HC600" manufactured by Tokyo Ohka Co., Ltd. is applied on a single-sided mirror-polished 6-inch Si wafer and rotated with a large spinner to prepare a resist layer having a thickness of 7 μm. Next, a preheat treatment is performed for about 20 minutes under a temperature condition of 70 ° C. using a ventilation oven with a nitrogen cycle.
b. The B side of the polyester film is laminated so as to be in contact with the resist layer, the polyester film is laminated on the resist layer using a rubber roller, and a reticle patterned with chrome metal is placed on the reticle. Exposure is performed from above using an I-line (ultraviolet ray having a peak at a wavelength of 365 nm) stepper.
c. After peeling the polyester film from the resist layer, the resist layer is placed in a container containing the developing solution N-A5 and developed for about 1 minute. Then, it is taken out from the developing solution and washed with water for about 1 minute. 30 states of L / S (μm) (Line and Space) = 10/10 μm of the resist pattern created after development were observed using a scanning electron microscope SEM at a magnification of about 800 to 3000, and the pattern was chipped. Evaluate as follows with a certain number.

Ａ；欠けのある本数が０から８本
Ｂ；欠けのある本数が９から１５本
Ｃ；欠けのある本数が１６本以上
Ａがレジスト性が最も良好で、Ｃが最も劣る。 A; The number of chips is 0 to 8 B; The number of chips is 9 to 15 C; The number of chips is 16 or more A has the best resistability and C is the worst.

なお、上記の測定において、測定するフィルムの長手方向や幅方向が分からない場合は、フィルムにおいて最大の屈折率を有する方向を長手方向、長手方向に直行する方向を幅方向とみなす。また、フィルムにおける最大の屈折率の方向は、フィルムの全ての方向の屈折率を屈折率計で測定して求めてもよく、位相差測定装置（複屈折測定装置）などにより遅相軸方向を決定することで求めてもよい。 In the above measurement, when the longitudinal direction and the width direction of the film to be measured are not known, the direction having the maximum refractive index in the film is regarded as the longitudinal direction, and the direction orthogonal to the longitudinal direction is regarded as the width direction. Further, the direction of the maximum refractive index in the film may be obtained by measuring the refractive index in all directions of the film with a refractive index meter, and the slow-phase axial direction is determined by a phase difference measuring device (birefringence measuring device) or the like. It may be obtained by deciding.

（１４）グリーンシート特性評価
以下ａ．からｂ．の方法により評価を行う。
ａ．離型層の塗布
二軸配向ポリエステルフィルムのＢ面に、架橋プライマー層（東レ・ダウコーニング・シリコーン（株）製商品名ＢＹ２４−８４６）を固形分１質量％に調整した塗布液を塗布／乾燥し、乾燥後の塗布厚みが０．１μｍとなるようにグラビアコーターで塗布し、１００℃で２０秒乾燥硬化した。その後１時間以内に付加反応型シリコーン樹脂（東レ・ダウコーニング・シリコーン（株）製商品名ＬＴＣ７５０Ａ）１００質量部、白金触媒（東レ・ダウコーニング・シリコーン（株）製商品名ＳＲＸ２１２）２質量部を固形分５質量％に調整した塗布液を、乾燥後の塗布厚みが０．１μｍとなるようにグラビアコートで塗布し、１２０℃で３０秒乾燥硬化した後に巻き取り、離型フィルムを得た。
ｂ．グリーンシートの塗布状態の評価（セラミックススラリーの塗布性）
チタン酸バリウム（富士チタン工業（株）製商品名ＨＰＢＴ−１）１００質量部、ポリビニルブチラール（積水化学（株）製商品名ＢＬ−１）１０質量部、フタル酸ジブチル５質量部とトルエン−エタノール（質量比３０：３０）６０質量部に、数平均粒径２ｍｍのガラスビーズを加え、ジェットミルにて２０時間混合・分散させた後、濾過してペースト状のセラミックスラリーを調整した。得られたセラミックスラリーを、離型フィルムの上に乾燥後の厚みが２μｍとなるように、ダイコーターにて塗布し乾燥させ、巻き取り、グリーンシートを得た。 上記で巻き取られたグリーンシートを、繰り出し、離型フィルムから剥がさない状態にて目視で観察し、ピンホールの有無や、シート表面および端部の塗布状態を確認する。なお観察する面積は幅３００ｍｍ、長さ５００ｍｍである。離型フィルムの上に成型されたグリーンシートについて、背面から１０００ルクスのバックライトユニットで照らしながら、塗布抜けによるピンホールあるいは、離型フィルム背面の表面転写による凹み状態を観察する。
Ａ：ピンホールも凹みも無い。
Ｂ：ピンホールは無く、凹みが３個以内認められる。
Ｃ：ピンホールが有り、また凹みが４個以上認められる。 (14) Evaluation of green sheet characteristics The following a. To b. Evaluation is performed by the method of.
a. Application of release layer
A coating solution prepared by adjusting a crosslinked primer layer (trade name BY24-846 manufactured by Toray Dow Corning Silicone Co., Ltd.) to a solid content of 1% by mass was applied / dried on the B side of the biaxially oriented polyester film, and after drying. It was coated with a gravure coater so that the coating thickness was 0.1 μm, and dried and cured at 100 ° C. for 20 seconds. Within 1 hour thereafter, 100 parts by mass of an addition reaction type silicone resin (trade name: LTC750A manufactured by Toray Dow Corning Silicone Co., Ltd.) and 2 parts by mass of a platinum catalyst (trade name: SRX212 manufactured by Toray Dow Corning Silicone Co., Ltd.). The coating liquid adjusted to a solid content of 5% by mass was coated with a gravure coat so that the coating thickness after drying was 0.1 μm, dried and cured at 120 ° C. for 30 seconds, and then wound to obtain a release film.
b. Evaluation of the coating state of the green sheet (applicability of ceramic slurry)
Barium titanate (trade name HPBT-1 manufactured by Fuji Titanium Industry Co., Ltd.) 100 parts by mass, polyvinyl butyral (trade name BL-1 manufactured by Sekisui Chemical Co., Ltd.) 10 parts by mass, dibutyl phthalate 5 parts by mass and toluene-ethanol (Mass ratio 30:30) Glass beads having a number average particle size of 2 mm were added to 60 parts by mass, mixed and dispersed by a jet mill for 20 hours, and then filtered to prepare a paste-like ceramic slurry. The obtained ceramic slurry was applied onto a release film with a die coater so that the thickness after drying was 2 μm, dried, and wound to obtain a green sheet. The green sheet wound up above is unwound and visually observed in a state where it is not peeled off from the release film, and the presence or absence of pinholes and the coating state of the sheet surface and edges are confirmed. The area to be observed is 300 mm in width and 500 mm in length. While illuminating the green sheet molded on the release film with a backlight unit of 1000 lux from the back surface, observe pinholes due to coating omission or dented state due to surface transfer on the back surface of the release film.
A: There are no pinholes or dents.
B: There are no pinholes, and no more than 3 dents are found.
C: There are pinholes, and 4 or more dents are recognized.

（１５）偏光板の目視検査
サンプルは、フィルム幅方向における任意の位置からＡ４のカットサンプルの長手方向とフィルム長手方向を一致させて切り出した。クロスニコル法として、光源部にフジカラーライトボックス１００Ｖ８Ｗ（（株）進光社製）を用いて、その上に正常な検光子と偏光子の吸収軸面が直交するように配置し、その間にポリエステルフィルムを挟んだ状態でＢ面が偏光子と接するように設置して、偏光子側から目視検査を行なった。このとき、観察面側の寸法幅２８ｃｍ×縦３４ｃｍの偏光子の吸収軸とＡ４カットサンプルのフィルムの長手方向を一致させた。目視検査は、まず、ポリエステルフィルムを挟んでない状態での輝点として表れる偏光子の異物や欠陥の位置と数を５０個、確認した。次に、ポリエステルフィルムを挟んだ状態で、異物や欠点の数が幾つ認識できなくなるかどうかで評価した。また、干渉色も同時に観察した。評価基準は以下に従った。
Ａ：確認できなくなる輝点数が５個未満。
Ｂ：確認できなくなる輝点数が５個以上１５個未満。
Ｃ：確認できなくなる輝点数が１５個以上。 (15) Visual Inspection of Polarizing Plate The sample was cut out from an arbitrary position in the film width direction so that the longitudinal direction of the A4 cut sample and the film longitudinal direction were aligned with each other. As a cross Nicol method, a Fuji Color Light Box 100V8W (manufactured by Shinko Co., Ltd.) is used for the light source, and the normal detector and the absorption axis of the polarizer are arranged so as to be orthogonal to each other, and polyester is placed between them. The film was placed so that the B surface was in contact with the polarizer with the film sandwiched between them, and a visual inspection was performed from the polarizer side. At this time, the absorption axis of the polarizer having a dimension width of 28 cm and a length of 34 cm on the observation surface side was made to coincide with the longitudinal direction of the film of the A4 cut sample. In the visual inspection, first, 50 positions and numbers of foreign substances and defects of the polarizing element appearing as bright spots without sandwiching the polyester film were confirmed. Next, it was evaluated by how many foreign substances and defects could not be recognized with the polyester film sandwiched between them. The interference color was also observed at the same time. The evaluation criteria were as follows.
A: The number of bright spots that cannot be confirmed is less than 5.
B: The number of bright spots that cannot be confirmed is 5 or more and less than 15.
C: The number of bright spots that cannot be confirmed is 15 or more.

次の実施例に基づき、本発明の実施形態を説明する。なお、ここでポリエチレンテレフタレートをＰＥＴ、ポリエチレンナフタレートをＰＥＮと表記する。 Embodiments of the present invention will be described based on the following examples. Here, polyethylene terephthalate is referred to as PET, and polyethylene naphthalate is referred to as PEN.

（１−ａ）ＰＥＴペレットの作製：テレフタル酸ジメチル１９４質量部とエチレングリコール１２４質量部とをエステル交換反応装置に仕込み、内容物を１４０℃に加熱して溶解した。その後、内容物を撹拌しながら酢酸マグネシウム四水和物０．３質量部および三酸化アンチモン０．０５質量部を加え、１４０〜２３０℃でメタノールを留出しつつエステル交換反応を行った。次いで、リン酸トリメチルの５質量％エチレングリコール溶液を０．５質量部（リン酸トリメチルとして０．０２５質量部）とリン酸二水素ナトリウム２水和物の５質量％エチレングリコール溶液を０．３質量部（リン酸二水素ナトリウム２水和物として０．０１５質量部）添加した。 (1-a) Preparation of PET pellets: 194 parts by mass of dimethyl terephthalate and 124 parts by mass of ethylene glycol were charged into a transesterification reaction apparatus, and the contents were heated to 140 ° C. to dissolve them. Then, while stirring the contents, 0.3 parts by mass of magnesium acetate tetrahydrate and 0.05 parts by mass of antimony trioxide were added, and a transesterification reaction was carried out while distilling out methanol at 140 to 230 ° C. Next, 0.5 parts by mass of a 5% by mass ethylene glycol solution of trimethyl phosphate (0.025 parts by mass as trimethyl phosphate) and 0.3 parts by mass of a 5% by mass ethylene glycol solution of monosodium dihydrogen phosphate dihydrate. By mass (0.015 parts by mass as sodium dihydrogen phosphate dihydrate) was added.

トリメチルリン酸のエチレングリコール溶液を添加すると反応内容物の温度が低下する。そこで余剰のエチレングリコールを留出させながら反応内容物の温度が２３０℃に復帰するまで撹拌を継続した。このようにしてエステル交換反応装置内の反応内容物の温度が２３０℃に達した後、反応内容物を重合装置へ移行した。 The addition of an ethylene glycol solution of trimethylphosphate lowers the temperature of the reaction contents. Therefore, stirring was continued until the temperature of the reaction contents returned to 230 ° C. while distilling off excess ethylene glycol. After the temperature of the reaction contents in the transesterification reactor reached 230 ° C. in this way, the reaction contents were transferred to the polymerization apparatus.

移行後、反応系を２３０℃から２７５℃まで徐々に昇温するとともに、圧力を０．１ｋＰａまで下げた。最終温度、最終圧力到達までの時間はともに６０分とした。最終温度、最終圧力に到達した後、２時間（重合を始めて３時間）反応させたところ、重合装置の撹拌トルクが所定の値（重合装置の仕様によって具体的な値は異なるが、本重合装置にて固有粘度０．５５のポリエチレンテレフタレートが示す値を所定の値とした）を示した。そこで反応系を窒素パージし常圧に戻して重縮合反応を停止し、冷水にストランド状に吐出、直ちにカッティングして固有粘度０．５５のポリエチレンテレフタレートのＰＥＴペレットを得た（原料−１）。 After the transition, the reaction system was gradually heated from 230 ° C. to 275 ° C. and the pressure was lowered to 0.1 kPa. The time required to reach the final temperature and the final pressure was 60 minutes. After reaching the final temperature and final pressure, the reaction was carried out for 2 hours (3 hours after the start of polymerization), and the stirring torque of the polymerization apparatus became a predetermined value (specific values differ depending on the specifications of the polymerization apparatus, but this polymerization apparatus The value indicated by polyethylene terephthalate having an intrinsic viscosity of 0.55 was set as a predetermined value). Therefore, the reaction system was purged with nitrogen and returned to normal pressure to stop the polycondensation reaction, discharged into cold water in a strand shape, and immediately cut to obtain PET pellets of polyethylene terephthalate having an intrinsic viscosity of 0.55 (raw material-1).

回転型真空重合装置を用いて、上記のＰＥＴペレット（原料−１）を０．１ｋＰａの減圧下２３０℃の温度で長時間加熱処理し、固相重合を行った（原料−１ｋ）。加熱処理時間が長いほど固有粘度は高くなる。処理時間が１時間で固有粘度が０．６０、５時間で固有粘度が０．７０である。 Using a rotary vacuum polymerization apparatus, the above PET pellets (raw material-1) were heat-treated for a long time at a temperature of 230 ° C. under a reduced pressure of 0.1 kPa to perform solid-phase polymerization (raw material-1k). The longer the heat treatment time, the higher the intrinsic viscosity. The treatment time is 1 hour and the intrinsic viscosity is 0.60, and the treatment time is 5 hours and the intrinsic viscosity is 0.70.

（１−ｂ）ＰＥＮペレットの作成：２，６−ナフタレンジカルボン酸ジメチル１２８質量部とエチレングリコール６０質量部の混合物に、酢酸マンガン・４水和物塩０．０２５質量部と酢酸ナトリウム・３水塩０．００５質量部を添加し、１５０℃の温度から２４０℃の温度に徐々に昇温しながらエステル交換反応を行った。途中、反応温度が１７０℃に達した時点で三酸化アンチモン０．０２４質量部を添加した。また、反応温度が２２０℃に達した時点で３，５−ジカルボキシベンゼンスルホン酸テトラブチルホスホニウム塩０．０４２質量部（２ｍｍｏｌ％に相当）を添加した。その後、引き続いてエステル交換反応を行い、トリメチルリン酸０．０２３質量部を添加した。次いで、反応生成物を重合装置に移し、２９０℃の温度まで昇温し、３０Ｐａの高減圧下にて重縮合反応を行い、重合装置の撹拌トルクが所定の値（重合装置の仕様によって具体的な値は異なるが、本重合装置にて固有粘度０．６のポリエチレン−２，６−ナフタレートが示す値を所定の値とした）を示した。そこで反応系を窒素パージし常圧に戻して重縮合反応を停止し、冷水にストランド状に吐出、直ちにカッティングして固有粘度０．６のＰＥＮペレット（原料−１ｂ）を得た。 (1-b) Preparation of PEN pellets: Manganese acetate / tetrahydrate salt 0.025 parts by mass and sodium acetate / 3 water in a mixture of 128 parts by mass of dimethyl 2,6-naphthalenedicarboxylic acid and 60 parts by mass of ethylene glycol. 0.005 parts by mass of salt was added, and the transesterification reaction was carried out while gradually raising the temperature from 150 ° C. to 240 ° C. On the way, when the reaction temperature reached 170 ° C., 0.024 parts by mass of antimony trioxide was added. Further, when the reaction temperature reached 220 ° C., 0.042 parts by mass (corresponding to 2 mmol%) of tetrabutylphosphonium salt of 3,5-dicarboxybenzenesulfonic acid was added. Then, a transesterification reaction was subsequently carried out, and 0.023 parts by mass of trimethylphosphate was added. Next, the reaction product is transferred to a polymerization apparatus, the temperature is raised to a temperature of 290 ° C., the polycondensation reaction is carried out under a high reduced pressure of 30 Pa, and the stirring torque of the polymerization apparatus is set to a predetermined value (specifically according to the specifications of the polymerization apparatus). Although the values are different, the value indicated by polyethylene-2,6-naphthalate having an intrinsic viscosity of 0.6 was used as the predetermined value in this polymerization apparatus). Therefore, the reaction system was purged with nitrogen and returned to normal pressure to stop the polycondensation reaction, discharged into cold water in a strand shape, and immediately cut to obtain PEN pellets (raw material-1b) having an intrinsic viscosity of 0.6.

（２−ａ）粒子含有ＰＥＴペレットの作製：２８０℃に加熱された同方向回転タイプのベント式２軸混練押出機に、上述の固相重合ＰＥＴペレット（原料−１ｋ：処理時間２時間）を９０質量部と平均粒径０．３０μｍの架橋ポリスチレン粒子の１０質量％水スラリーを１０質量部（架橋ポリスチレン粒子として１質量部）を供給し、ベント孔を１ｋＰａ以下の減圧度に保持し水分を除去し、架橋ポリスチレン粒子を１質量％含有する固有粘度０．６２の粒子含有ペレット（原料−２ａ）を得た。 (2-a) Preparation of particle-containing PET pellets: The above-mentioned solid polystyrene PET pellets (raw material-1k: treatment time 2 hours) were applied to a vent-type twin-screw kneading extruder heated to 280 ° C. in the same direction. 10 parts by mass of 10% by mass water slurry of cross-linked polystyrene particles having 90 parts by mass and an average particle size of 0.30 μm (1 part by mass as cross-linked polystyrene particles) was supplied, and the vent holes were maintained at a reduced pressure of 1 kPa or less to retain water. The particles were removed to obtain particle-containing pellets (raw material-2a) having an intrinsic viscosity of 0.62 containing 1% by mass of crosslinked polystyrene particles.

（２−ｂ）粒子含有ＰＥＴペレットの作製：２８０℃に加熱された同方向回転タイプのベント式２軸混練押出機に、上述の固相重合ＰＥＴペレット（原料−１ｋ：処理時間２時間）を９０質量部と平均粒径０．２μｍの架橋ポリスチレン粒子の１０質量％水スラリーを１０質量部（架橋ポリスチレン粒子として１質量部）を供給し、ベント孔を１ｋＰａ以下の減圧度に保持し水分を除去し、架橋ポリスチレン粒子を１質量％含有する固有粘度０．６２の粒子含有ペレット（原料−２ｂ）を得た。 (2-b) Preparation of particle-containing PET pellets: The above-mentioned solid polystyrene PET pellets (raw material-1k: treatment time 2 hours) were applied to a vent-type twin-screw kneading extruder heated to 280 ° C. in the same direction. 10 parts by mass of 10% by mass water slurry of cross-linked polystyrene particles having 90 parts by mass and an average particle size of 0.2 μm (1 part by mass as cross-linked polystyrene particles) is supplied, and the vent holes are maintained at a reduced pressure of 1 kPa or less to retain water. The particles were removed to obtain particle-containing pellets (raw material-2b) having an intrinsic viscosity of 0.62 containing 1% by mass of crosslinked polystyrene particles.

（２−ｃ）粒子含有ＰＥＴペレットの作製：２８０℃に加熱された同方向回転タイプのベント式２軸混練押出機に、上述の固相重合ＰＥＴペレット（原料−１ｋ：処理時間２時間）を９０質量部と平均粒径０．１０μｍのコロイダルシリカ粒子の１０質量％水スラリーを１０質量部（コロイダルシリカ粒子として１質量部）を供給し、ベント孔を１ｋＰａ以下の減圧度に保持し水分を除去し、コロイダルシリカ粒子を１質量％含有する固有粘度０．６２の粒子含有ペレット（原料−２ｃ）を得た。 (2-c) Preparation of particle-containing PET pellets: The above-mentioned solid-phase polymerized PET pellets (raw material-1k: treatment time 2 hours) were applied to a vent-type twin-screw kneading extruder heated to 280 ° C. in the same direction. 10 parts by mass (1 part by mass as colloidal silica particles) of 10% by mass water slurry of colloidal silica particles having 90 parts by mass and an average particle size of 0.10 μm is supplied, and the vent holes are maintained at a reduced pressure of 1 kPa or less to retain water. The particles were removed to obtain particle-containing pellets (raw material-2c) having an intrinsic viscosity of 0.62 containing 1% by mass of colloidal silica particles.

（２−ｄ）粒子含有ＰＥＴペレットの作製：２８０℃に加熱された同方向回転タイプのベント式２軸混練押出機に、上述の固相重合ＰＥＴペレット（原料−１ｋ：処理時間２時間）を９０質量部と平均粒径０．０３０μｍのコロイダルシリカ粒子の１０質量％水スラリーを１０質量部（コロイダルシリカ粒子として１質量部）を供給し、ベント孔を１ｋＰａ以下の減圧度に保持し水分を除去し、コロイダルシリカ粒子を１質量％含有する固有粘度０．６２の粒子含有ペレット（原料−２ｄ）を得た。 (2-d) Preparation of particle-containing PET pellets: The above-mentioned solid-phase polymerized PET pellets (raw material-1k: treatment time 2 hours) were applied to a vent-type twin-screw kneading extruder heated to 280 ° C. in the same direction. 10 parts by mass (1 part by mass as colloidal silica particles) of 10% by mass water slurry of colloidal silica particles having 90 parts by mass and an average particle size of 0.030 μm was supplied, and the vent holes were maintained at a reduced pressure of 1 kPa or less to retain water. The particles were removed to obtain particle-containing pellets (raw material-2d) having an intrinsic viscosity of 0.62 containing 1% by mass of colloidal silica particles.

（２−ｅ）粒子含有ＰＥＮペレットの作製：２９０℃に加熱された同方向回転タイプのベント式２軸混練押出機に、上述のＰＥＮペレット（原料−１ｂ）を９０質量部と平均粒径０．３０μｍの架橋ポリスチレン粒子の１０質量％水スラリーを１０質量部（架橋ポリスチレン粒子として１質量部）を供給し、ベント孔を１ｋＰａ以下の減圧度に保持し水分を除去し、架橋ポリスチレン粒子を１質量％含有する固有粘度０．６の粒子含有ペレット（原料−２ｅ）を得た。 (2-e) Preparation of particle-containing PEN pellets: 90 parts by mass of the above-mentioned PEN pellets (raw material-1b) and an average particle size of 0 in a vent-type twin-screw kneading extruder heated to 290 ° C. A 10% by mass water slurry of .30 μm crosslinked polystyrene particles was supplied in an amount of 10 parts by mass (1 part by mass as crosslinked polystyrene particles), the vent holes were maintained at a reduced pressure of 1 kPa or less to remove water, and the crosslinked polystyrene particles were removed by 1. Particle-containing pellets (raw material-2e) containing mass% and having an intrinsic viscosity of 0.6 were obtained.

（２−ｆ）粒子含有ＰＥＮペレットの作製：２９０℃に加熱された同方向回転タイプのベント式２軸混練押出機に、上述のＰＥＮペレット（原料−１ｂ）を９０質量部と平均粒径０．１０μｍのコロイダルシリカ粒子の１０質量％水スラリーを１０質量部（コロイダルシリカ粒子として１質量部）を供給し、ベント孔を１ｋＰａ以下の減圧度に保持し水分を除去し、コロイダルシリカ粒子を１質量％含有する固有粘度０．６の粒子含有ペレット（原料−２ｆ）を得た。 (2-f) Preparation of particle-containing PEN pellets: 90 parts by mass of the above-mentioned PEN pellets (raw material-1b) and an average particle size of 0 in a vent-type twin-screw kneading extruder heated to 290 ° C. . Supply 10 parts by mass (1 part by mass as colloidal silica particles) of 10 mass% water slurry of 10 μm colloidal silica particles, keep the vent holes at a reduced pressure of 1 kPa or less to remove water, and remove 1 mass% of colloidal silica particles. Particle-containing pellets (raw material-2f) containing mass% and having an intrinsic viscosity of 0.6 were obtained.

（２−ｇ）粒子含有ＰＥＮペレットの作製：２９０℃に加熱された同方向回転タイプのベント式２軸混練押出機に、上述のＰＥＮペレット（原料−１ｂ）を９０質量部と平均粒径０．０３μｍのコロイダルシリカ粒子の１０質量％水スラリーを１０質量部（コロイダルシリカ粒子として１質量部）を供給し、ベント孔を１ｋＰａ以下の減圧度に保持し水分を除去し、コロイダルシリカ粒子を１質量％含有する固有粘度０．６の粒子含有ペレット（原料−２ｇ）を得た。 (2-g) Preparation of particle-containing PEN pellets: 90 parts by mass of the above-mentioned PEN pellets (raw material-1b) and an average particle size of 0 in a vent-type twin-screw kneading extruder heated to 290 ° C. A 10% by mass water slurry of .03 μm colloidal silica particles was supplied in an amount of 10 parts by mass (1 part by mass as colloidal silica particles), the vent holes were maintained at a reduced pressure of 1 kPa or less to remove water, and 1 colloidal silica particles were removed. Particle-containing pellets (raw material-2 g) containing mass% and having an intrinsic viscosity of 0.6 were obtained.

（実施例１）
押出機Ｅ１、Ｅ２の２台を用い、２８０℃に加熱された押出機Ｅ１には、Ａ層原料として、固相重合を４時間実施したＰＥＴペレット（原料−１ｋ）を７０質量部、平均粒径０．０３μｍのコロイダルシリカ粒子含有ペレット（原料−２ｄ）３０質量部を１８０℃で３時間減圧乾燥した後に供給した。同じく２８０℃に加熱された押出機Ｅ２には、Ｂ層原料として、Ａ層で用いたＰＥＴペレット（原料−１ｋ）を６０質量部、平均粒径０．１μｍのコロイダルシリカ粒子含有ペレット（原料−２ｃ）３０質量部、平均粒径０．３０μｍの架橋ポリスチレン粒子含有ペレット（原料−２ａ）１０質量部を配合し、１８０℃で３時間減圧乾燥した後に供給した。これらを２層積層するべくＴダイ中で積層厚み比（Ａ層｜Ｂ層）＝１．２５｜１とし、Ｂ層側がキャストドラム面側になるように合流させ、ドラフト比（口金のリップ間隙／未延伸フィルム厚み）＝２０となるように表面温度２５℃のキャストドラムに静電荷を印加させながら密着冷却固化し、積層未延伸フィルムを作製した。 (Example 1)
In the extruder E1 heated to 280 ° C. using two extruders E1 and E2, 70 parts by mass of PET pellets (raw material-1k) subjected to solid phase polymerization for 4 hours as a raw material for layer A, average particles. 30 parts by mass of colloidal silica particle-containing pellets (raw material-2d) having a diameter of 0.03 μm were dried under reduced pressure at 180 ° C. for 3 hours before being supplied. In the extruder E2, which was also heated to 280 ° C., 60 parts by mass of PET pellets (raw material-1k) used in the A layer as a raw material for the B layer and colloidal polystyrene particle-containing pellets having an average particle size of 0.1 μm (raw material-) were used. 2c) 10 parts by mass of crosslinked polystyrene particle-containing pellets (raw material-2a) having an average particle size of 0.30 μm and 30 parts by mass were blended, dried under reduced pressure at 180 ° C. for 3 hours, and then supplied. In order to stack two layers of these, the stacking thickness ratio (A layer | B layer) = 1.25 | 1 is set in the T die, and the layers are merged so that the B layer side is on the cast drum surface side, and the draft ratio (lip gap of the base) is set. / Unstretched film thickness) = 20, a cast drum having a surface temperature of 25 ° C. was subjected to close contact cooling and solidification while applying an electrostatic charge to prepare a laminated unstretched film.

この積層未延伸フィルムをロール式延伸機にて８８℃で３段階にて長手方向に３．５倍延伸した。この延伸は２組ずつのロールの周速差を利用し１段目に２．８倍、２段目１．２倍、３段目１．０５倍で行った。 This laminated unstretched film was stretched 3.5 times in the longitudinal direction in three steps at 88 ° C. using a roll-type stretching machine. This stretching was performed at 2.8 times in the first stage, 1.2 times in the second stage, and 1.05 times in the third stage using the difference in peripheral speed between the two sets of rolls.

得られた一軸延伸フィルムの両端をクリップで把持しながらテンター内の９５℃の温度の予熱ゾーンに導き、引き続き連続的に１００℃の温度の加熱ゾーンで長手方向に直角な幅方向（ＴＤ方向）に３．５倍延伸し（ＴＤ延伸１）、さらに続いて１７０℃の温度の加熱ゾーンでに幅方向に１．３倍延伸した（ＴＤ延伸２）。引き続いて、テンター内の熱処理ゾーンで温度１８０℃で１．１倍延伸した（ＴＤ延伸３）後に、温度１９０℃、２１０℃に徐々に温度を上げながら合計２０秒間の熱処理を施した後、さらに１５０℃の温度で０．５％幅方向に弛緩処理を行った。次いで、２５℃に均一に冷却後、フィルムエッジを除去し、コア上に巻き取って厚さ４．５μｍの二軸延伸ポリエステルフィルムを得た。得られた二軸配向ポリエステルフィルムの製膜安定性は良好であり、物性評価したところ、表に示すように、磁気テープとして使用した際に優れた特性を有していた。 While gripping both ends of the obtained uniaxially stretched film with clips, it is guided to a preheating zone having a temperature of 95 ° C. in the tenter, and continuously in a heating zone having a temperature of 100 ° C. in the width direction (TD direction) perpendicular to the longitudinal direction. Was stretched 3.5 times (TD stretch 1), and subsequently stretched 1.3 times in the width direction in a heating zone at a temperature of 170 ° C. (TD stretch 2). Subsequently, after stretching 1.1 times at a temperature of 180 ° C. (TD stretching 3) in the heat treatment zone in the tenter, heat treatment was performed for a total of 20 seconds while gradually increasing the temperature to 190 ° C. and 210 ° C., and then further. The relaxation treatment was performed in the width direction of 0.5% at a temperature of 150 ° C. Then, after cooling uniformly to 25 ° C., the film edge was removed, and the film was wound on a core to obtain a biaxially stretched polyester film having a thickness of 4.5 μm. The film-forming stability of the obtained biaxially oriented polyester film was good, and when the physical properties were evaluated, as shown in the table, it had excellent properties when used as a magnetic tape.

以下、表に各実施例、比較例の原料組成、製膜条件、二軸配向ポリエステルフィルムの物性、磁気テープの特性等を示す。 Below, the table shows the raw material composition of each Example and Comparative Example, the film forming conditions, the physical properties of the biaxially oriented polyester film, the characteristics of the magnetic tape, and the like.

（実施例２〜６）
表に示すように各種粒子原料を所定の濃度になるよう配合量や積層厚みを変更した以外は全て実施例１と同様にして厚さ４．５μｍの二軸延伸ポリエステルフィルムを得た。 (Examples 2 to 6)
As shown in the table, a biaxially stretched polyester film having a thickness of 4.5 μm was obtained in the same manner as in Example 1 except that the blending amount and the laminated thickness of various particle raw materials were changed so as to have a predetermined concentration.

（実施例７）
押出機Ｅ１、Ｅ２の２台を用い、３００℃に加熱された押出機Ｅ１には、Ａ層原料として、ＰＥＮペレット（原料−１ｂ）７０質量部、平均粒径０．０３μｍのコロイダルシリカ粒子含有ペレット（原料−２ｇ）３０質量部を１８０℃で３時間減圧乾燥した後に供給した。同じく３００℃に加熱された押出機Ｅ２には、Ｂ層原料として、Ａ層で用いたＰＥＮペレット（原料−１ｂ）を６０質量部、平均粒径０．１μｍのコロイダルシリカ粒子含有ペレット（原料−２ｆ）３０質量部、平均粒径０．３０μｍの架橋ポリスチレン粒子含有ペレット（原料−２ｅ）１０質量部、を配合し、１８０℃で３時間減圧乾燥した後に供給した。これらを２層積層するべくＴダイ中で積層厚み比（Ａ層｜Ｂ層）＝１．２５｜１とし、Ｂ層側がキャストドラム面側になるように合流させ、ドラフト比（口金のリップ間隙／未延伸フィルム厚み）＝２０となるように表面温度２５℃のキャストドラムに静電荷を印加させながら密着冷却固化し、積層未延伸フィルムを作製した。 (Example 7)
Extruder E1 heated to 300 ° C. using two extruders E1 and E2 contains 70 parts by mass of PEN pellets (raw material-1b) and colloidal silica particles having an average particle size of 0.03 μm as a raw material for layer A. 30 parts by mass of pellets (raw material-2 g) were dried under reduced pressure at 180 ° C. for 3 hours before being supplied. In the extruder E2, which was also heated to 300 ° C., 60 parts by mass of the PEN pellets (raw material-1b) used in the A layer as the raw material for the B layer and colloidal polystyrene particle-containing pellets having an average particle size of 0.1 μm (raw material-) were used. 2f) 30 parts by mass and 10 parts by mass of crosslinked polystyrene particle-containing pellets (raw material-2e) having an average particle size of 0.30 μm were blended and dried under reduced pressure at 180 ° C. for 3 hours before being supplied. In order to stack two layers of these, the stacking thickness ratio (A layer | B layer) = 1.25 | 1 is set in the T die, and the layers are merged so that the B layer side is on the cast drum surface side, and the draft ratio (lip gap of the base) is set. / Unstretched film thickness) = 20, a cast drum having a surface temperature of 25 ° C. was subjected to close contact cooling and solidification while applying an electrostatic charge to prepare a laminated unstretched film.

この積層未延伸フィルムをロール式延伸機にて１２５℃で３段階で長手方向に４．５倍延伸した。この延伸は２組ずつのロールの周速差を利用し１段目に３．６倍、２段目１．２倍、３段目１．０５倍で行った。 This laminated unstretched film was stretched 4.5 times in the longitudinal direction in three steps at 125 ° C. using a roll-type stretching machine. This stretching was performed at 3.6 times in the first stage, 1.2 times in the second stage, and 1.05 times in the third stage using the difference in peripheral speed between the two sets of rolls.

得られた一軸延伸フィルムの両端をクリップで把持しながらテンター内の１３０℃の温度の予熱ゾーンに導き、引き続き連続的に１３５℃の温度の加熱ゾーンで長手方向に直角な幅方向（ＴＤ方向）に４倍延伸し（ＴＤ延伸１）、さらに続いて１７０℃の温度の加熱ゾーンでに幅方向に１．５倍延伸した（ＴＤ延伸２）。引き続いて、テンター内の熱処理ゾーンで温度１８０℃で１．１倍延伸した（ＴＤ延伸３）後に、温度１９０℃、２１０℃に徐々に温度を上げながら合計２０秒間の熱処理を施した後、さらに１５０℃の温度で０．５％幅方向に弛緩処理を行った。次いで、２５℃に均一に冷却後、フィルムエッジを除去し、コア上に巻き取って厚さ４．５μｍの二軸延伸ポリエステルフィルムを得た。 While gripping both ends of the obtained uniaxially stretched film with clips, it is guided to a preheating zone having a temperature of 130 ° C. in the tenter, and continuously in a heating zone having a temperature of 135 ° C. in the width direction (TD direction) perpendicular to the longitudinal direction. (TD stretching 1), followed by 1.5 times stretching in the width direction in a heating zone at a temperature of 170 ° C. (TD stretching 2). Subsequently, after stretching 1.1 times at a temperature of 180 ° C. (TD stretching 3) in the heat treatment zone in the tenter, heat treatment was performed for a total of 20 seconds while gradually increasing the temperature to 190 ° C. and 210 ° C., and then further. The relaxation treatment was performed in the width direction of 0.5% at a temperature of 150 ° C. Then, after cooling uniformly to 25 ° C., the film edge was removed, and the film was wound on a core to obtain a biaxially stretched polyester film having a thickness of 4.5 μm.

（実施例８）
押出機Ｅ１、Ｅ２およびＥ３の３台を用い、２８０℃に加熱された押出機Ｅ１には、Ａ層原料として、固相重合を４時間実施したＰＥＴペレット（原料−１ｋ）を７０質量部、平均粒径０．０３μｍのコロイダルシリカ粒子含有ペレット（原料−２ｄ）３０質量部を１８０℃で３時間減圧乾燥した後に供給した。同じく２８０℃に加熱された押出機Ｅ２には、Ｂ層原料として、Ａ層で用いたＰＥＴペレット（原料−１ｋ）を６０質量部、平均粒径０．１μｍのコロイダルシリカ粒子含有ペレット（原料−２ｃ）３０質量部、平均粒径０．３０μｍの架橋ポリスチレン粒子含有ペレット（原料−２ａ）１０質量部を配合し、１８０℃で３時間減圧乾燥した後に供給した。さらに、同じく２８０℃に加熱された押出機Ｅ３には、Ｃ層としてＰＥＴペレット（原料１−ｋ）を１８０℃で３時間減圧乾燥した後に供給した。これらを３層積層するべくＴダイ中で積層厚み比（Ａ層｜Ｃ層｜Ｂ層）＝２．０｜１．０｜１．５とし、Ｂ層側がキャストドラム面側になるように合流させ、ドラフト比（口金のリップ間隙／未延伸フィルム厚み）＝２０となるように表面温度２５℃のキャストドラムに静電荷を印加させながら密着冷却固化し、積層未延伸フィルムを作製した。 (Example 8)
Using three extruders E1, E2 and E3, the extruder E1 heated to 280 ° C. was charged with 70 parts by mass of PET pellets (raw material-1k) subjected to solid phase polymerization for 4 hours as a raw material for layer A. 30 parts by mass of colloidal silica particle-containing pellets (raw material-2d) having an average particle size of 0.03 μm were dried under reduced pressure at 180 ° C. for 3 hours before being supplied. In the extruder E2, which was also heated to 280 ° C., 60 parts by mass of PET pellets (raw material-1k) used in the A layer as a raw material for the B layer and colloidal polystyrene particle-containing pellets having an average particle size of 0.1 μm (raw material-) were used. 2c) 10 parts by mass of crosslinked polystyrene particle-containing pellets (raw material-2a) having an average particle size of 0.30 μm and 30 parts by mass were blended, dried under reduced pressure at 180 ° C. for 3 hours, and then supplied. Further, PET pellets (raw material 1-k) were supplied as the C layer to the extruder E3, which was also heated to 280 ° C., after being dried under reduced pressure at 180 ° C. for 3 hours. In order to stack these three layers, the stacking thickness ratio (A layer | C layer | B layer) = 2.0 | 1.0 | 1.5 is set in the T die, and the layers are merged so that the B layer side is the cast drum surface side. Then, the cast drum having a surface temperature of 25 ° C. was closely cooled and solidified while applying an electrostatic charge so that the draft ratio (lip gap of the base / thickness of the unstretched film) was 20 to prepare a laminated unstretched film.

この積層未延伸フィルムをロール式延伸機にて８８℃で３段階にて長手方向に３．５倍延伸した。この延伸は２組ずつのロールの周速差を利用し１段目に２．８倍、２段目１．２倍、３段目１．０５倍で行った。 This laminated unstretched film was stretched 3.5 times in the longitudinal direction in three steps at 88 ° C. using a roll-type stretching machine. This stretching was performed at 2.8 times in the first stage, 1.2 times in the second stage, and 1.05 times in the third stage using the difference in peripheral speed between the two sets of rolls.

得られた一軸延伸フィルムの両端をクリップで把持しながらテンター内の９５℃の温度の予熱ゾーンに導き、引き続き連続的に１００℃の温度の加熱ゾーンで長手方向に直角な幅方向（ＴＤ方向）に３．５倍延伸し（ＴＤ延伸１）、さらに続いて１７０℃の温度の加熱ゾーンでに幅方向に１．３倍延伸した（ＴＤ延伸２）。引き続いて、テンター内の熱処理ゾーンで温度１８０℃で１．１倍延伸した（ＴＤ延伸３）後に、温度１９０℃、２１０℃に徐々に温度を上げながら合計２０秒間の熱処理を施した後、さらに１５０℃の温度で０．５％幅方向に弛緩処理を行った。次いで、２５℃に均一に冷却後、フィルムエッジを除去し、コア上に巻き取って厚さ４．５μｍの二軸延伸ポリエステルフィルムを得た。得られた二軸配向ポリエステルフィルムの製膜安定性は良好であり、物性評価したところ、表に示すように、磁気テープとして使用した際に優れた特性を有していた。 While gripping both ends of the obtained uniaxially stretched film with clips, it is guided to a preheating zone having a temperature of 95 ° C. in the tenter, and continuously in a heating zone having a temperature of 100 ° C. in the width direction (TD direction) perpendicular to the longitudinal direction. Was stretched 3.5 times (TD stretch 1), and subsequently stretched 1.3 times in the width direction in a heating zone at a temperature of 170 ° C. (TD stretch 2). Subsequently, after stretching 1.1 times at a temperature of 180 ° C. (TD stretching 3) in the heat treatment zone in the tenter, heat treatment was performed for a total of 20 seconds while gradually increasing the temperature to 190 ° C. and 210 ° C., and then further. The relaxation treatment was performed in the width direction of 0.5% at a temperature of 150 ° C. Then, after cooling uniformly to 25 ° C., the film edge was removed, and the film was wound on a core to obtain a biaxially stretched polyester film having a thickness of 4.5 μm. The film-forming stability of the obtained biaxially oriented polyester film was good, and when the physical properties were evaluated, as shown in the table, it had excellent properties when used as a magnetic tape.

（実施例９）
押出機Ｅ１、Ｅ２およびＥ３の３台を用い、２８０℃に加熱された押出機Ｅ１には、Ａ層原料として、固相重合を４時間実施したＰＥＴペレット（原料−１ｋ）を７０質量部、平均粒径０．０３μｍのコロイダルシリカ粒子含有ペレット（原料−２ｄ）３０質量部を１８０℃で３時間減圧乾燥した後に供給した。同じく２８０℃に加熱された押出機Ｅ２には、Ｂ層原料として、Ａ層で用いたＰＥＴペレット（原料−１ｋ）を６０質量部、平均粒径０．１μｍのコロイダルシリカ粒子含有ペレット（原料−２ｃ）３０質量部、平均粒径０．３０μｍの架橋ポリスチレン粒子含有ペレット（原料−２ａ）１０質量部を配合し、１８０℃で３時間減圧乾燥した後に供給した。さらに、同じく２８０℃に加熱された押出機Ｅ３には、Ｃ層としてＰＥＴペレット（原料１−ｋ）を１８０℃で３時間減圧乾燥した後に供給した。これらを３層積層するべくＴダイ中で積層厚み比（Ａ層｜Ｃ層｜Ｂ層）＝２．０｜１２．５｜１．５とし、Ｂ層側がキャストドラム面側になるように合流させ、ドラフト比（口金のリップ間隙／未延伸フィルム厚み）＝２０となるように表面温度２５℃のキャストドラムに静電荷を印加させながら密着冷却固化し、積層未延伸フィルムを作製した。 (Example 9)
Using three extruders E1, E2 and E3, the extruder E1 heated to 280 ° C. was charged with 70 parts by mass of PET pellets (raw material-1k) subjected to solid phase polymerization for 4 hours as a raw material for layer A. 30 parts by mass of colloidal silica particle-containing pellets (raw material-2d) having an average particle size of 0.03 μm were dried under reduced pressure at 180 ° C. for 3 hours before being supplied. In the extruder E2, which was also heated to 280 ° C., 60 parts by mass of PET pellets (raw material-1k) used in the A layer as a raw material for the B layer and colloidal polystyrene particle-containing pellets having an average particle size of 0.1 μm (raw material-) were used. 2c) 10 parts by mass of crosslinked polystyrene particle-containing pellets (raw material-2a) having an average particle size of 0.30 μm and 30 parts by mass were blended, dried under reduced pressure at 180 ° C. for 3 hours, and then supplied. Further, PET pellets (raw material 1-k) were supplied as the C layer to the extruder E3, which was also heated to 280 ° C., after being dried under reduced pressure at 180 ° C. for 3 hours. In order to stack these three layers, the stacking thickness ratio (A layer | C layer | B layer) = 2.0 | 12.5 | 1.5 in the T die, and the B layer side is merged so as to be the cast drum surface side. Then, the cast drum having a surface temperature of 25 ° C. was closely cooled and solidified while applying an electrostatic charge so that the draft ratio (lip gap of the base / thickness of the unstretched film) was 20 to prepare a laminated unstretched film.

この積層未延伸フィルムをロール式延伸機にて８８℃で３段階にて長手方向に３．５倍延伸した。この延伸は２組ずつのロールの周速差を利用し１段目に２．８倍、２段目１．２倍、３段目１．０５倍で行った。 This laminated unstretched film was stretched 3.5 times in the longitudinal direction in three steps at 88 ° C. using a roll-type stretching machine. This stretching was performed at 2.8 times in the first stage, 1.2 times in the second stage, and 1.05 times in the third stage using the difference in peripheral speed between the two sets of rolls.

得られた一軸延伸フィルムの両端をクリップで把持しながらテンター内の９５℃の温度の予熱ゾーンに導き、引き続き連続的に１００℃の温度の加熱ゾーンで長手方向に直角な幅方向（ＴＤ方向）に３．３倍延伸し（ＴＤ延伸１）、さらに続いて１７０℃の温度の加熱ゾーンでに幅方向に１．２倍延伸した（ＴＤ延伸２）。引き続いて、テンター内の熱処理ゾーンで温度１８０℃で１．０５倍延伸した（ＴＤ延伸３）後に、温度１９０℃、２１０℃に徐々に温度を上げながら合計２０秒間の熱処理を施した後、さらに１５０℃の温度で０．５％幅方向に弛緩処理を行った。次いで、２５℃に均一に冷却後、フィルムエッジを除去し、コア上に巻き取って厚さ１６μｍの二軸延伸ポリエステルフィルムを得た。得られた二軸配向ポリエステルフィルムの製膜安定性は良好であり、物性評価したところ、表に示すとおりであり、レジスト特性評価はＡランク、グリーンシート特性評価はＡランク、偏光板目視検査はＡランクである優れた特性を有していた。 While gripping both ends of the obtained uniaxially stretched film with clips, it is guided to a preheating zone having a temperature of 95 ° C. in the tenter, and continuously in a heating zone having a temperature of 100 ° C. in the width direction (TD direction) perpendicular to the longitudinal direction. It was stretched 3.3 times (TD stretch 1), and subsequently stretched 1.2 times in the width direction in a heating zone at a temperature of 170 ° C. (TD stretch 2). Subsequently, after stretching 1.05 times at a temperature of 180 ° C. (TD stretching 3) in the heat treatment zone in the tenter, heat treatment was performed for a total of 20 seconds while gradually increasing the temperature to 190 ° C. and 210 ° C., and then further. The relaxation treatment was performed in the width direction of 0.5% at a temperature of 150 ° C. Then, after uniformly cooling to 25 ° C., the film edge was removed and wound on a core to obtain a biaxially stretched polyester film having a thickness of 16 μm. The film-forming stability of the obtained biaxially oriented polyester film was good, and the physical properties were evaluated as shown in the table. The resist characteristic evaluation was A rank, the green sheet characteristic evaluation was A rank, and the polarizing plate visual inspection was performed. It had excellent characteristics of A rank.

（比較例１〜５）
表に示すように各種粒子原料を所定の濃度になるよう配合量や積層厚みを変更した以外は全て実施例１と同様にして厚さ４．５μｍの二軸延伸ポリエステルフィルムを得た。 (Comparative Examples 1 to 5)
As shown in the table, a biaxially stretched polyester film having a thickness of 4.5 μm was obtained in the same manner as in Example 1 except that the blending amount and the laminated thickness of various particle raw materials were changed so as to have a predetermined concentration.

（比較例６）
実施例１と同様にして得た一軸延伸フィルムの両端をクリップで把持しながらテンター内の９５℃の温度の予熱ゾーンに導き、引き続き連続的に１００℃の温度の加熱ゾーンで長手方向に直角な幅方向（ＴＤ方向）に３．５倍延伸し（ＴＤ延伸１）、さらに続いて１７０℃の温度の加熱ゾーンでに幅方向に１．４倍延伸した（ＴＤ延伸２）。引き続いて、温度１９０℃、２１０℃に徐々に温度を上げながら合計２０秒間の熱処理を施した後、さらに１５０℃の温度で０．５％幅方向に弛緩処理を行った。次いで、２５℃に均一に冷却後、フィルムエッジを除去し、コア上に巻き取って厚さ４．５μｍの二軸延伸ポリエステルフィルムを得た。 (Comparative Example 6)
While gripping both ends of the uniaxially stretched film obtained in the same manner as in Example 1 with clips, the film is guided to a preheating zone having a temperature of 95 ° C. in the tenter, and is continuously perpendicular to the longitudinal direction in a heating zone having a temperature of 100 ° C. It was stretched 3.5 times in the width direction (TD direction) (TD stretch 1), and subsequently stretched 1.4 times in the width direction in a heating zone at a temperature of 170 ° C. (TD stretch 2). Subsequently, the heat treatment was performed for a total of 20 seconds while gradually increasing the temperature to 190 ° C. and 210 ° C., and then the relaxation treatment was further performed at a temperature of 150 ° C. in the width direction of 0.5%. Then, after cooling uniformly to 25 ° C., the film edge was removed, and the film was wound on a core to obtain a biaxially stretched polyester film having a thickness of 4.5 μm.

Figure 0006926616
Figure 0006926616

Figure 0006926616
Figure 0006926616

Figure 0006926616
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Claims (17)

表層を構成する少なくともＡ層とＢ層の２層を含む二軸配向積層ポリエステルフィルムであって、Ａ層厚みがＢ層厚みより大きく、Ａ層表面のＡＦＭによる基準面からのしきい値６０ｎｍにおける突起個数が１０個／５０μｍ２以下であり、かつ、Ｂ層表面における三次元粗さ計による基準面から高さ６０ｎｍ以上の突起密度（Ｍ６０）が１００個／ｍｍ２未満である、二軸配向積層ポリエステルフィルム。 A biaxially oriented laminated polyester film containing at least two layers, A layer and B layer, which constitute a surface layer, in which the thickness of the A layer is larger than the thickness of the B layer and the threshold value of the AFM surface is 60 nm from the reference plane. Biaxial orientation in which the number of protrusions is 10 pieces / 50 μm 2 or less, and the protrusion density (M60) having a height of 60 nm or more from the reference plane by a three-dimensional roughness meter on the B layer surface is less than 100 pieces / mm 2. Laminated polyester film. 前記Ａ層表面の中心線表面粗さＲａが０．１〜３ｎｍである、請求項１記載の二軸配向積層ポリエステルフィルム。 The biaxially oriented laminated polyester film according to claim 1, wherein the center line surface roughness Ra of the surface of the layer A is 0.1 to 3 nm. 前記Ａ層表面における波長９．６５μｍにおけるパワースペクトル密度（ＰＳＤ）が１，０００〜５０，０００ｎｍ３の範囲にある、請求項１または２に記載の二軸配向積層ポリエステルフィルム。 The biaxially oriented laminated polyester film according to claim 1 or 2, wherein the power spectral density (PSD) at a wavelength of 9.65 μm on the surface of the layer A is in the range of 1,000 to 50,000 nm 3. 前記Ｂ層の積層厚み（ｔ）が０．５〜２．０μｍであり、かつ、該層に含有される粒子の最大粒子径（Ｄ）との比（ｔ／Ｄ）が５以上１０以下である、請求項１〜３のいずれかに記載の二軸配向積層ポリエステルフィルム。 The laminated thickness (t) of the B layer is 0.5 to 2.0 μm, and the ratio (t / D) of the particles contained in the layer to the maximum particle size (D) is 5 or more and 10 or less. The biaxially oriented laminated polyester film according to any one of claims 1 to 3. 三次元粗さ計によるＢ層表面の突起密度が以下の関係を満足する、請求項１〜４のいずれかに記載の二軸配向積層ポリエステルフィルム。
０．４＜（Ｍ６０／Ｍ１０）×１００＜５
（但し、Ｍ１０（個／ｍｍ２）：基準面から高さ１０ｎｍ以上の突起密度、Ｍ６０（個／ｍｍ２）:基準面から高さ６０ｎｍ以上の突起密度） The biaxially oriented laminated polyester film according to any one of claims 1 to 4, wherein the protrusion density on the surface of the B layer by a three-dimensional roughness meter satisfies the following relationship.
0.4 <(M60 / M10) x 100 <5
(However, M10 (pieces / mm 2 ): protrusion density of height 10 nm or more from the reference surface, M60 (pieces / mm 2 ): protrusion density of height 60 nm or more from the reference surface) 厚みが３．５〜４．５μｍである、請求項１〜５のいずれかに記載の二軸配向積層ポリエステルフィルム。 The biaxially oriented laminated polyester film according to any one of claims 1 to 5, which has a thickness of 3.5 to 4.5 μm. 幅方向の湿度膨張係数が０〜８ｐｐｍ／％ＲＨである、請求項１〜６のいずれかに記載の二軸配向積層ポリエステルフィルム。 The biaxially oriented laminated polyester film according to any one of claims 1 to 6, wherein the humidity expansion coefficient in the width direction is 0 to 8 ppm /% RH. ３層以上の積層構造からなる請求項１〜７のいずれかに記載の二軸配向積層ポリエステルフィルム。 The biaxially oriented laminated polyester film according to any one of claims 1 to 7, which has a laminated structure of three or more layers. 塗布型デジタル記録方式の磁気記録媒体用ベースフィルムに用いられる、請求項１〜８のいずれかに記載の二軸配向積層ポリエステルフィルム。 The biaxially oriented laminated polyester film according to any one of claims 1 to 8, which is used as a base film for a coating type digital recording type magnetic recording medium. 請求項１〜９のいずれかに記載の二軸配向積層ポリエステルフィルムを用いた磁気記録媒体。 A magnetic recording medium using the biaxially oriented laminated polyester film according to any one of claims 1 to 9. 離型用または工程用フィルムとして用いられる、請求項１〜８のいずれかに記載の二軸配向積層ポリエステルフィルム。 The biaxially oriented laminated polyester film according to any one of claims 1 to 8, which is used as a film for mold release or a process. ドライフィルムレジスト基材用フィルムとして用いられる、請求項１１に記載の二軸配向積層ポリエステルフィルム。 The biaxially oriented laminated polyester film according to claim 11, which is used as a film for a dry film resist base material. 積層セラミックコンデンサーを製造する工程においてグリーンシート成形の支持体として用いられる、請求項１１に記載の二軸配向積層ポリエステルフィルム。 The biaxially oriented laminated polyester film according to claim 11, which is used as a support for forming a green sheet in a process of manufacturing a laminated ceramic capacitor. 偏光板離型用フィルムとして用いられる、請求項１１に記載の二軸配向積層ポリエステルフィルム。 The biaxially oriented laminated polyester film according to claim 11, which is used as a polarizing plate release film. 光学部材用フィルムとして用いられる、請求項１〜８のいずれかに記載の二軸配向積層ポリエステルフィルム。 The biaxially oriented laminated polyester film according to any one of claims 1 to 8, which is used as a film for an optical member. 請求項１〜１５のいずれかに記載の二軸配向積層ポリエステルフィルムの製造方法であって、長手方向に延伸した後に幅方向に延伸する工程を有し、前記長手方向の延伸および／または幅方向の延伸を２段階以上に分けて実施する二軸配向積層ポリエステルフィルムの製造方法。The method for producing a biaxially oriented laminated polyester film according to any one of claims 1 to 15, further comprising a step of stretching in the longitudinal direction and then stretching in the width direction, and stretching in the longitudinal direction and / or the width direction. A method for producing a biaxially oriented laminated polyester film in which the stretching of the film is carried out in two or more steps. 前記長手方向に延伸した後に幅方向に延伸する工程の後に熱固定処理する工程を有し、前記熱固定処理を２段階以上に分けて実施する請求項１６に記載の二軸配向積層ポリエステルフィルムの製造方法。The biaxially oriented laminated polyester film according to claim 16, further comprising a step of stretching in the longitudinal direction and then stretching in the width direction, followed by a heat fixing treatment, and the heat fixing treatment is carried out in two or more steps. Production method.
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