JP3678226B2 - Heat-shrinkable polyester film roll - Google Patents

Description

【００４１】
［式中、ｆ（ｘ）は断面曲線を示しており、詳しくは測定方向に設定した座標ｘにおける凹凸の大きさ（平均線よりも高いときを正、平均線よりも低いときを負とする）を意味する。Ｌは測定長さを示す］
＜結晶性＞
本発明のフィルムロールでは、このロールに巻回されたフィルムが実質的に非晶性を示す場合もあり、実質的に結晶性を示す場合もある。非晶性のフィルムを用いると、結晶部分での収縮阻害が起こらないため、フィルムの熱収縮率を高くしても熱収縮時の外観不良の発生を防止できる。このため、高い熱収縮率が要求されるフルラベル（容器を全体に亘って被覆するためのラベル）用途に特に適している。また低温での熱収縮性にも優れている場合が多い。従って、高い熱収縮率又は低温での熱収縮性が求められる場合は、非晶性のフィルムを用いるのが望ましく、高い熱収縮率や低温での熱収縮性が求められない汎用用途においては、結晶性のフィルムを用いるのが望ましい。
【００４２】
なお実質的に結晶性であるとは、フィルムを溶融状態から急冷した後、所定の速度（例えば、２０℃／分程度）でゆっくりと昇温したときに、結晶化に伴う発熱ピーク、及び融解に伴う吸熱ピークが観測されることをいい、実質的に非晶性であるとは、前記発熱ピーク及び吸熱ピークが観測されないことをいう。
【００４３】
＜結晶化温度＞
一方、前記フィルムが実質的に結晶性を示す場合、フィルムの結晶化温度は１００℃以上（好ましくは１１０℃以上）であるのが望ましい。結晶化温度が低すぎると、フィルム（ラベル）を加熱して熱収縮させる際に、結晶化が生じ、収縮応力の持続性が低下する場合がある。そのため収縮時に発生する収縮斑の緩和が困難となり、仕上がり外観が低下する場合がある。なお結晶化温度の上限は特に限定されないが、例えば、１５０℃以下程度、好ましくは１４５℃以下程度である。
【００４４】
さらに結晶化温度（℃）も、前記ガラス転移温度（Ｔｇ）と同様に定常領域において、フィルムの流れ方向に高いレベルで均一化されているのが望ましい。結晶化温度が均一化されていると、裁断時のトラブル（熱融着、カットミス）やラベル同士のブロッキングの発生をさらに抑制することができる。しかも前記収縮斑の緩和を安定化することができ、仕上がり外観不良による歩留まり低下を防止できる。
【００４５】
結晶化温度の均一性は、前記ガラス転移温度（Ｔｇ）を測定する場合と同様に設けた各切出し箇所からの試料の結晶化温度を測定することにより評価できる。本発明のフィルムロールでは、全試料の結晶化温度の平均値を算出したとき、各箇所の試料の結晶化温度が、例えば、前記平均値の±５℃以内（好ましくは±４℃以内、さらに好ましくは±３℃以内）になるように均一化されているのが望ましい。すなわち、各試料の結晶化温度Ｃｎ（℃）と全試料の平均ガラス転移温度Ｃａｖ（℃）との差の絶対値（｜Ｃｎ−Ｃａｖ｜）が、例えば、５℃以下（好ましくは４℃以下、さらに好ましくは３℃以下）になるように均一化されているのが望ましい。換言すれば、Ｃｎの最大値（Ｃｍａｘ）とＣａｖとの差、及びＣｎの最小値（Ｃｍｉｎ）とＣａｖとの差のいずれもが±５℃以内（好ましくは±４℃以内、さらに好ましくは±３℃以内）であれば、前記要件を満足する。
【００４６】
なお結晶化温度は、フィルムから切出した試料１０±１ｍｇを温度３００℃で２分間加熱し、直ちに液体窒素に入れて急冷した後、温度−４０℃から３００℃まで速度２０℃／分で昇温し、示差走査熱量測定装置（ＤＳＣ）で熱流速曲線（ＤＳＣ曲線）を求めることにより測定できる。結晶化温度は、前記熱流速曲線における発熱ピークの最大値を示す温度を意味する。
【００４７】
＜融解温度＞
さらに前記フィルムが実質的に結晶性を示す場合、フィルムの融解温度は１８０℃以上（好ましくは１８５℃、さらに好ましくは１９５℃以上）であるのが望ましい。前記結晶性のフィルムが高収縮率用途や低温収縮用途に優れているのに対して、融解温度が高い結晶性フィルムは高温でも熱収縮可能であり汎用性に優れている。なお融解温度が高くなりすぎるとラベル加工時のシール性（ヒートシール性、溶剤接着性など）が低下したり、熱収縮率が低下してラベル収縮後の仕上がり外観が低下する。従ってフィルムの融解温度は、通常、２３０℃以下（好ましくは２２５℃以下、さらに好ましくは２２０℃以下である）。
【００４８】
また融解温度（℃）も、前記ガラス転移温度（Ｔｇ）と同様に、フィルムの流れ方向に高いレベルで均一化されているのが望ましい。融解温度が均一化されていると、裁断時のトラブル（熱融着、カットミス）やラベル同士のブロッキングの発生をさらに抑制することができる。しかも前記シール性の低下や熱収縮率の低下（仕上がり外観の低下）を抑制でき、歩留まり低下を防止できる。
【００４９】
融解温度の均一性は、前記ガラス転移温度（Ｔｇ）を測定する場合と同様に設けた各切出し箇所からの試料の融解温度を測定することにより評価できる。本発明のフィルムロールでは、全試料の融解温度の平均値を算出したとき、各箇所の試料の融解温度が、例えば、前記平均値の±５℃以内（好ましくは±４℃以内、さらに好ましくは±３℃以内）になるように均一化されているのが望ましい。すなわち、各試料の融解温度Ｍｎ（℃）と全試料の融解温度Ｍａｖ（℃）との差の絶対値（｜Ｍｎ−Ｍａｖ｜）が、例えば、５℃以下（好ましくは４℃以下、さらに好ましくは３℃以下）になるように均一化されている。換言すれば、Ｍｎの最大値（Ｍｍａｘ）とＭａｖとの差、及びＭｎの最小値（Ｍｍｉｎ）とＭａｖとの差のいずれもが±５℃以内（好ましくは±４℃以内、さらに好ましくは±３℃以内）であれば、前記要件を満足する。
【００５０】
なお融解温度は、フィルムから切出した試料１０±１ｍｇを温度３００℃で２分間加熱し、直ちに液体窒素に入れて急冷した後、温度−４０℃から３００℃まで速度２０℃／分で昇温し、示差走査熱量測定装置（ＤＳＣ）で熱流速曲線（ＤＳＣ曲線）を求めることにより測定できる。融解温度は、前記熱流速曲線における吸熱ピークの最大値を示す温度を意味する。
【００５１】
＜ポリエステル系フィルム＞
上述のような特性を有する本発明のフィルムロールに巻回されるポリエステル系熱収縮性フィルムとしては、ポリエステル系フィルムであって熱収縮性を有する限り特に限定されない。
【００５２】
ポリエステル系フィルム（熱収縮性ポリエステル系フィルム）としては、ジカルボン酸成分と多価アルコール成分とで構成されるフィルムが使用できる。より詳細には、前記フィルムは、ベースユニット（例えば、ポリエチレンテレフタレートなどの結晶性ユニットなど）を構成する第１のジカルボン酸成分（例えば、テレフタル酸成分など）及び第１の多価アルコール成分（例えば、エチレングリコール成分など）と、この第１のジカルボン酸成分とは異なる第２のジカルボン酸成分、及び／又は第１の多価アルコール成分とは異なる第２の多価アルコール成分を含有している。第２のジカルボン酸成分及び／又は第２の多価アルコール成分（好ましくは第２のアルコール成分）によってフィルムの結晶性の有無、熱的性質（熱収縮率、ガラス転移温度、結晶化温度、融解温度など）を調整できる。
【００５３】
ジカルボン酸成分（第１のジカルボン酸成分、第２のジカルボン酸成分）を形成するジカルボン酸類としては、例えば、芳香族ジカルボン酸、そのエステル形成誘導体、脂肪族ジカルボン酸などが利用可能である。芳香族ジカルボン酸としては、例えば、テレフタル酸、イソフタル酸、ナフタレン−１，４−もしくは−２，６−ジカルボン酸、５−ナトリウムスルホイソフタル酸などが挙げられる。またエステル誘導体としてはジアルキルエステル、ジアリールエステル等の誘導体が挙げられる。脂肪族ジカルボン酸としては、ダイマー酸、グルタル酸、アジピン酸、セバシン酸、アゼライン酸、シュウ酸、コハク酸等が挙げられる。前記ジカルボン酸成分のうち、イソフタル酸成分、ナフタレン−１，４−もしくは−２，６−ジカルボン酸成分などはフィルムを非晶化するために有用な成分であり、フィルムの熱収縮性を高めることができる。
【００５４】
なお前記ジカルボン酸類に加えて、ｐ−オキシ安息香酸等のオキシカルボン酸類；無水トリメリット酸、無水ピロメリット酸などの三価以上のカルボン酸を必要に応じて併用してもよい。
【００５５】
第２のジカルボン酸成分の割合は、例えば、ジカルボン酸成分１００モル％中、３〜８０モル％程度、好ましくは５〜７５モル％程度、さらに好ましくは１０〜７０モル％程度である。
【００５６】
前記多価アルコール成分（第１の多価アルコール成分、第２の多価アルコール成分）は、ジオール成分であってもよく、三価以上のアルコール成分であってもよい。ジオール成分を形成するジオールには、エチレングリコール、プロピレングリコール、１，４−ブタンジオール、ネオペンチルグリコール、２，２−ジエチル−１，３−プロパンジオール、１，６−ヘキサンジオール、３−メチル−１，５−ペンタンジオール、２−メチル−１，５−ペンタンジオール、１，９−ノナンジオール、１，１０−デカンジオールなどのアルキレングリコール；１，４−シクロヘキサンジメタノールなどの環状アルコール；ジエチレングリコール、トリエチレングリコール、ポリエチレングリコール、ポリプロピレングリコール、ポリオキシテトラメチレングリコール、ビスフェノール化合物またはその誘導体のアルキレンオキサイド付加物などのエーテルグリコール類；ダイマージオールなどが含まれる。三価以上のアルコールには、トリメチロールプロパン、グリセリン、ペンタエリスリトールなどが含まれる。前記多価アルコール成分のうち、１，４−シクロヘキサンジメタノール成分、ネオペンチルグリコール成分などはフィルムを非晶化するために有用な成分であり、フィルムの熱収縮性を高めることができる。また１，４−ブタンジオール成分、プロピレングリコール成分などは、フィルムのガラス転移温度を低下させ、低温でも熱収縮可能にするのに有用な成分である。
【００５７】
第２のアルコール成分の割合は、例えば、多価アルコール成分１００モル％中、３〜８０モル％程度、好ましくは５〜７５モル％程度、さらに好ましくは１０〜７０モル％程度である。
【００５８】
なおポリエステルは、ラクトン類（ε−カプロラクトンなど）の開環重合によって製造してもよい。
【００５９】
好ましい第２のジカルボン酸成分及び第２のアルコール成分には、非晶性の成分（イソフタル酸成分、ナフタレン−１，４−もしくは−２，６−ジカルボン酸成分、１，４−シクロヘキサンジメタノール成分、ネオペンチルグリコール成分など）が含まれる。これらの成分のうち少なくとも一つを含有させると非晶性のフィルムを得ることができる。非晶性のフィルムを得る場合、非晶性のジカルボン酸成分の割合は、ジカルボン酸成分１００モル％中、例えば、１５モル％以上、好ましくは１８モル％以上、さらに好ましくは２０モル％以上であり、非晶性の多価アルコール成分の割合は、多価アルコール成分１００モル％中、例えば、１５モル％以上、好ましくは１８モル％以上、さらに好ましくは２０モル％以上である。
【００６０】
＜滑材（微粒子）＞
本発明の熱収縮性ポリエステル系フィルムロールは、３次元表面粗さＳＲｚ、及びＳΔａを所定の範囲に制御するため、滑材を含有している。
【００６１】
前記滑材としては、無機微粒子（無機滑材）、有機塩微粒子、高分子微粒子などが挙げられる。無機粒子には、炭酸塩（炭酸カルシウム、炭酸マグネシウム、炭酸バリウムなどの炭酸アルカリ土類金属塩など）、硫酸塩（硫酸バリウムなどの硫酸アルカリ土類金属塩など）、リン酸塩（リン酸リチウムなどのリン酸アルカリ金属塩、リン酸カルシウム、リン酸マグネシウムなどのリン酸アルカリ土類金属塩など）、酸化物系粒子（酸化アルミニウム、酸化珪素、酸化チタン、酸化ジルコニウムなど）、カオリン、タルク、フッ化リチウムなどが挙げられる。特に好ましい無機粒子は、シリカ粒子である。このシリカ粒子は、１次粒子が凝集してできた凝集体であることがさらに望ましい。シリカ粒子は、良好なハンドリング性を有しており、しかも透明性の優れたフィルムを得るのに有用である。
【００６２】
有機塩粒子としては、蓚酸塩（蓚酸カルシウムなどの蓚酸アルカリ土類金属塩など）、テレフタル酸塩（カルシウム塩、マグネシウム塩、バリウム塩などのアルカリ土類金属塩、亜鉛塩、マンガン塩など）などが挙げられる。
【００６３】
高分子粒子としては、ジビニルベンゼン、スチレン、（メタ）アクリル酸などのビニル系モノマーの単独又は共重合体、ポリテトラフルオロエチレン、ベンゾグアナミン樹脂、熱硬化性尿素樹脂、熱硬化性フェノール樹脂などが挙げられる。好ましい高分子粒子は、架橋高分子粒子である。
【００６４】
滑材の粒径及び含有量は、３次元表面粗さＳＲｚ及び／又はＳΔａを所定の範囲に制御できる限り特に限定されないが、例えば、下記の範囲から選択する。
【００６５】
粒径： 例えば、０．０１μｍ以上（好ましくは０．０５μｍ以上、さらに好ましくは１μｍ以上）、４μｍ以下（好ましくは３．５μｍ以下、さらに好ましくは３μｍ以下）
滑材の粒径が小さすぎると、３次元表面粗さＳＲｚ及び／又はＳΔａが小さくなり過ぎる場合がある。また滑材の粒径が大きすぎると、３次元表面粗さＳＲｚ及び／又はＳΔａが大きくなり過ぎる場合がある。
【００６６】
含有量： 例えば、０．０２質量％以上（好ましくは０．０３質量％以上、さらに好ましくは０．０４質量％以上）、０．５質量％以下（好ましくは０．４質量％以下、さらに好ましくは０．２質量％以下）
滑材の含有量が少なすぎると、３次元表面粗さＳＲｚが小さくなり過ぎる場合がある。また滑材の含有量が多すぎると、３次元表面粗さＳＲｚが大きくなり過ぎる場合がある。
【００６７】
［製造方法］
本発明では、単独の原料チップからフィルムロールを製造してもよいが、複数種の原料チップ（原料ペレット）を混合し、押出機から押出して製膜した後、延伸することによって熱収縮性フィルムを製造し、このフィルムを巻き取ることによって前記フィルムロールを製造するのが望ましい。複数種の原料チップを混合するのは、チップの配合比を調整することによって、ラベルの用途に応じてフィルムの物性を簡単に調製できるためだけでなく、複数種の原料チップを混合すると、各チップ間で熱的特性や滑材含有量などが異なるためフィルムの熱的特性や３次元表面粗さＳＲｚなどが特に安定し難いにも拘らず、本発明によれば、前記熱的特性（ガラス転移温度、結晶化温度、融解温度など、好ましくはガラス転移温度）や３次元表面粗さＳＲｚなどを安定化させることができ、特に有用であるためである。
【００６８】
＜原料ポリエステル系チップの製造方法＞
ポリエステル系チップの製造方法は特に限定されず、公知の方法（溶融重合法、その他の重合法など）によって得ることができる。溶融重合法としては、例えば、ジカルボン酸とグリコール類との直接反応から得られるオリゴマーを重縮合する方法（直接重合法）、ジカルボン酸のジメチルエステル体とグリコールとをエステル交換反応させたのちに重縮合する方法（エステル交換法）、その他の任意の製造法を適用できる。前記重合に際しては、ホモポリエステル及び共重合ポリエステルのいずれを製造してもよい。ポリエステルの重合度は、極限粘度（固有粘度）にして０．５〜１．３ｄｌ／ｇ程度のものが好ましい。
【００６９】
重合触媒としては、慣用の種々の触媒が使用でき、例えば、チタン系触媒、アンチモン系触媒、ゲルマニウム系触媒、スズ系触媒、コバルト系触媒、マンガン系触媒など、好ましくはチタン系触媒（チタニウムテトラブトキシドなど）、アンチモン系触媒（三酸化アンチモンなど）、ゲルマニウム系触媒（二酸化ゲルマニウムなど）、コバルト系触媒（酢酸コバルトなど）などが挙げられる。
【００７０】
ポリエステルには、フィルムロールを製造したときの３次元表面粗さＳＲｚなどを制御するため、前記重合触媒の他に、上記滑材（微粒子）を添加する。滑材（微粒子）の添加時期は特に限定されず、ポリエステルの重合工程の任意の段階で添加してもよく、ポリエステルの製造後に該ポリエステルを再溶融させてから添加してもよい。なお本発明では、通常、複数のポリエステル系チップを混合してフィルムロールを製造するが、全てのチップに滑材を添加しておく必要はなく、１つのチップに滑材を添加しておき、該チップをマスターバッチとして使用するのが簡便である。
【００７１】
またポリエステルには、着色やゲル発生などの不都合を抑制するため、前記重合触媒及び滑材以外に、リン酸やリン酸エステル誘導体（リン酸トリエチルエステルなど）などのリン酸類、金属塩（酢酸マグネシウム、塩化マグネシウムなどのＭｇ塩；酢酸カルシウム、塩化カルシウムなどのＣａ塩；酢酸マンガン、塩化マンガンなどのＭｎ塩；塩化亜鉛、酢酸亜鉛などのＺｎ塩；塩化コバルト、酢酸コバルトなどのＣｏ塩など）などを添加してもよい。リン酸類の添加量は、ポリエステル中の燐原子の濃度が２００ｐｐｍ（質量基準）以下になる程度であり、金属塩の添加量は、ポリエステル中の金属イオン濃度が３００ｐｐｍ（質量基準）以下になる程度である。リン酸類や金属塩を添加し過ぎると、ポリエステルの着色が顕著になるのみならず、ポリエステルの耐熱性や耐加水分解性が低下する。
【００７２】
リン酸類と金属塩とを添加する場合、総Ｐ量（Ｐ）と総金属イオン量（Ｍ）とのモル原子比（Ｐ／Ｍ）が、０．４〜１．０となるように添加するのが望ましい。前記割合で添加すると、前記耐熱性の低下や耐加水分解性の低下を防止できる。なお前記割合を逸脱すると、フィルムが着色したり、フィルム中に粗大粒子が混入する場合がある。
【００７３】
上記リン酸類及び金属塩の添加時期は特に限定されないが、一般的には、リン酸類は重縮合反応前に添加するのが好ましく、金属塩は原料仕込み時、すなわちエステル交換前またはエステル化前に添加するのが好ましい。
【００７４】
さらに必要に応じて、酸化防止剤、紫外線吸収剤、帯電防止剤、着色剤、抗菌剤等を添加することもできる。
【００７５】
＜原料チップの混合・押出・製膜＞
本発明では、上述したように、通常、熱的特性（ガラス転移温度など）や滑材含有量が異なる複数種の原料チップを混合し、押出して製膜している。例えば、ポリエステル系フィルムを製造する場合、組成や重合度など（特に組成）が異なるポリエステル系チップを混合することが多い。組成が異なるチップを混合することにより、フィルム中の組成を簡単に調整することができ、フィルムの結晶性や熱的特性を制御することができる。また滑材を含有するチップ（マスターバッチ）を用い、滑材を含有しないチップと混合すれば、簡便に滑材含有量を制御することができる。
【００７６】
ポリエステル系チップを混合する場合、複数種のホモポリエステルチップを混合してもよく、複数種の共重合ポリエステルチップを混合してもよく、ホモポリエステルチップと共重合ポリエステルチップとを混合してもよい。ホモポリエステルチップ及び共重合ポリエステルチップとしては、フィルム中のジカルボン酸成分及び多価アルコール成分を上述の組成に調整できる種々のチップが使用できるが、好ましいホモポリエステルチップには、ポリエチレンテレフタレートチップ、ポリブチレンテレフタレートチップ、ポリシクロへキシレンジメチレンテレフタレートチップ、ポリエチレンナフタレートチップなどが含まれる。好ましい共重合ポリエステルチップには、ジカルボン酸成分がテレフタル酸成分であり、多価アルコール成分がエチレングリコール成分及び非晶性の多価アルコール成分（１，４−シクロヘキサンジメタノール成分、ネオペンチルグリコール成分など）であるチップ；ジカルボン酸成分がテレフタル酸成分及びナフタレン−１，４−又は−２，６−ジカルボン酸成分であり、多価アルコール成分がエチレングリコール成分、ダイマージオール成分、及びポリテトラメチレングリコール成分（例えば、分子量５００〜８００程度、好ましくは６００〜７００程度、特に６５０程度のポリテトラメチレングリコール成分）であるチップなどが含まれる。
【００７７】
そして上述したように、複数種の原料チップを混合して押し出す場合、通常の方法に従って混合・押出しするとフィルムの熱的特性や滑材含有量（すなわちフィルムの３次元表面粗さＳＲｚ）が安定し難いため、本発明では特定の方法で混合・押出しすることにより、フィルムの熱的特性や３次元表面粗さＳＲｚを安定化している。
【００７８】
すなわち通常の方法で複数種の原料チップを混合・押出しする場合、具体的には、下記（１）又は（２）で示す手順を採用することが多い。（１）複数種の原料チップを混合用ホッパに連続式又は間欠式に供給し、必要に応じて緩衝ホッパを介し、最終的に押出機直前又は直上のホッパ（最終ホッパ）に供給する方法。（２）最終ホッパで各原料チップを混合し、押出機の押出量に合わせて前記混合チップを定量的に押出機に供給し、製膜する方法。
【００７９】
ところが最終ホッパ内のチップ残量が多い場合と少ない場合とでは、最終ホッパから押出機へと供給される混合チップの組成が異なってくるという原料偏析（原料偏在）の現象が発生していることを本発明者等は見出した。この現象は最終ホッパの容量や形状が不適切な場合に発生し易く、特に各原料チップの形状や比重が互いに異なる場合に顕著に現れる。その結果、フィルムの流れ方向の熱的特性や３次元表面粗さＳＲｚが大きく変動してしまう虞がある。
【００８０】
熱的特性が均一化されたフィルムを得る方法としては、最終ホッパ内での原料偏析（原料偏在）を抑止する方法、例えば、（１）各原料チップの形状を合わせる方法、（２）微粉状の原料チップを低減する方法、（３）最終ホッパの形状を適正化する方法、（４）最終ホッパの容量を適正化する方法などが挙げられる。
【００８１】
（１）各原料チップの形状を合わせる方法
各原料チップの形状を合わせると、前記原料偏析を低減できる。すなわちチップの大きさに違いがあると、最終ホッパ内を混合チップが落下していくときに、小さいチップは先に落下し易いため、最終ホッパ内のチップ残量が少なくなると、大きいチップの比率が多くなって、原料偏析が現われる。これに対して、各原料チップの形状を合わせると、小さいチップが先に落下するのを防止でき、原料偏析を低減できる。
【００８２】
例えばポリエステル系チップは、通常、重合後の溶融状態で重合装置よりストランド状で取り出され、直ちに水冷した後、ストランドカッターでカットして形成される。このためポリエステル系チップは、通常、横断面が楕円形の楕円柱状となる。従って各ポリエステル系チップの形状を合わせる場合、各ポリエステル系チップの横断面楕円の平均長径（ｍｍ）及び平均短径（ｍｍ）、並びに平均チップ長さ（ｍｍ）を合わせるのが望ましい。
【００８３】
好ましくは使用量の最も多い原料チップ（最多チップ）に混合する他の原料チップとして、その横断面楕円の平均長径（ｍｍ）及び平均短径（ｍｍ）、並びに平均チップ長さ（ｍｍ）が最多チップのそれらに対して、それぞれ±２０％以内の範囲となるチップ、好ましくはそれぞれ±１５％以内の範囲となるチップを使用する。
【００８４】
（２）微粉状の原料チップを低減する方法
使用する原料チップの削れ等により発生する微粉体（微粉状の原料チップ）は、原料偏析の発生を助長するので、前記微粉体の比率を低減することによっても、原料偏析を抑制できる。
【００８５】
原料チップ中の微粉体の比率は、原料チップが押出機に入るまでの全工程を通じて、１質量％以内に制御することが好ましく、０．５質量％以内に制御することがさらに好ましい。
【００８６】
微粉体を低減する方法としては、例えば、工程内で発生する微粉体を除去する方法が採用できる。例えば、篩やサイクロン式エアフィルタを用いて、微粉体を除去することができる。
【００８７】
（３）最終ホッパの形状を適正化する方法
例えば、最終ホッパとして、漏斗状ホッパを用い、その斜辺（側壁）を垂直に近づける方法が挙げられる。斜辺（側壁）を垂直に近づければ、大きいチップも小さいチップと同様に落とし易くすることができ、内容物の上端部が水平面を保ちつつ下降していくため、原料偏析の低減に効果的である。
【００８８】
前記斜辺（側壁）の傾斜角は、例えば、６５゜以上、好ましくは７０°以上である。なお、斜辺（側壁）の傾斜角とは、漏斗状の斜辺（側壁）と、水平な線分との間の角度である。
【００８９】
最終ホッパの上流に複数のホッパ（各チップ供給用のホッパなど）を使用する場合、これら複数のホッパにおいても、傾斜角を６５゜以上、好ましくは７０゜以上とするのが好ましい。
【００９０】
（４）最終ホッパの容量を適正化する方法
最終ホッパで混合した混合チップを、時間をかけて前記最終ホッパから押出機へ吐出すると、フィード中に混合チップの偏析（偏在）が発生する場合がある。
【００９１】
従ってホッパ内の混合チップの存在時間を短くするようにすれば、すなわち比較的短時間で混合チップを排出できる程度にホッパの容量を小さくすれば、原料偏析を抑制できる。
【００９２】
ホッパの適正な容量としては、例えば、（押出機の１時間当たりの吐出量）の５〜１２０質量％の範囲内、好ましくは（押出機の１時間当たりの吐出量）の１０〜１００質量％の範囲内程度である。
【００９３】
上記原料偏析を低減する方法（１）〜（４）は、いずれか一つを採用してもよく、複数採用してもよいが、好ましくは方法（１）（各原料チップの形状を合わせる方法）を採用し、必要に応じて残りの方法（２）〜（４）を採用する。
【００９４】
複数種の原料チップの混合手順としては、上記従来の手順のいずれを採用してもよいが、押出機直上のホッパ（最終ホッパ）で各原料チップを連続的に押出機へ定量供給しながら、各原料チップを混合する方法が最も好ましい。また、原料チップサイズを前述の範囲内に制御したものを予め混合した後、いくつかの中間（緩衝）ホッパを介して、最終ホッパおよび押出機に供給してもよい。複数種の原料チップを混合する際には、連続供給式の定量供給装置からホッパ内に複数種の原料チップを定量的に供給しながら混合する方法、ブレンダー等を使用して事前に混合する方法などが採用できるが、後者の場合には、混合物の排出時に原料偏析が発生しないように、原料チップサイズ等に留意することが好ましい。
【００９５】
なお前記原料チップは、押出し前の適当な段階で乾燥しておくのが望ましい。例えば、原料チップを乾燥機（ホッパドライヤー、パドルドライヤー、真空乾燥機など）を用いて乾燥し、押出機を用いて適当な温度（例えば、２００〜３００℃程度）でフィルム状に押してもよく、未乾燥の原料チップをベント式押出機内で水分を除去しながら適当な温度（例えば、２００〜３００℃程度）でフィルム状に押し出してもよい。
【００９６】
押出しに際してはＴダイ法、チューブラ法など、既存の種々の方法が採用できる。押出し後は、キャスティングロールなどの冷却用ロールで急冷することによって、未延伸フィルムを得るのが望ましい。
【００９７】
＜延伸＞
そして本発明では、前記未延伸フィルムを、フィルムの種類に応じて適当な倍率で延伸することによって、フィルムの熱収縮率を上記所定の範囲、すなわち最大収縮方向の熱収縮率が２０％以上になるように制御している。
【００９８】
延伸処理のタイミングは特に限定されず、例えば、前記冷却用ロール（キャスティングロールなど）による冷却後、一旦ロール状に巻き取り、このロールからフィルムを引き出して延伸処理してもよく、該冷却後、ロール状に巻き取ることなく連続的に延伸処理してもよい。
【００９９】
延伸方向（フィルムの最大収縮方向）は、フィルムの横（幅）方向であってもよく、フィルムの縦方向（流れ方向）であってもよいが、延伸方向をフィルムの横（幅）方向にすることが生産効率の点で実用的であるため、以下、延伸方向（最大収縮方向）を横方向とする場合の延伸法を例にとって説明する。なお、延伸方向（フィルムの最大収縮方向）をフィルム縦（長手）方向とする場合は、下記方法における延伸方向を９０゜変える等、通常の操作に準じて延伸すればよい。
【０１００】
横方向に延伸する場合、テンターなどの慣用の延伸手段を用いて延伸処理することができる。
【０１０１】
最大収縮方向（この例では、横方向）の延伸倍率は、熱収縮率を２０％以上にでき、かつ３次元表面粗さＳＲｚを所定の範囲に制御できる限り特に限定されず、フィルムの種類に応じて適宜選択できるが、延伸倍率が適正でない場合には滑材による突起形成が不十分となる場合があるため、例えば、２．３〜７．３倍程度、さらに好ましくは２．５〜６．０倍程度とする。延伸温度は、通常の方法に従って設定できる。
【０１０２】
なお延伸は、最大収縮方向（この例では、横方向）のみに延伸する１軸延伸に限定されず、前記最大収縮方向と異なる方向（例えば、直交方向；この例では、フィルムの縦方向）にも延伸する２軸延伸を行ってもよい。異方向（この例では、縦方向）への延伸倍率は、前記最大収縮方向（横方向）への延伸倍率以下であればよく、例えば、１倍〜４倍程度、好ましくは１．１倍〜２倍程度である。２軸延伸のタイミングは特に限定されず、例えば、逐次２軸延伸、同時２軸延伸のいずれでもよく、必要に応じて、再延伸を行ってもよい。また、逐次２軸延伸を行う場合、延伸順序も特に限定されず、縦横、横縦、縦横縦、横縦横など、いずれの順序で延伸してもよい。
【０１０３】
延伸処理後は、６０℃〜１１０℃の範囲内の所定温度で、０〜１５％の伸張あるいは０〜１５％の緩和をさせながら熱処理し、必要に応じて４０℃〜１００℃の範囲内の所定温度でさらに熱処理をするのが望ましい。
【０１０４】
なお前記延伸処理に先立ってフィルムを予備加熱しておいてもよい。予備加熱では、例えば、ガラス転移温度（Ｔｇ）＋０℃〜Ｔｇ＋６０℃程度の温度にフィルムを加熱する。
【０１０５】
上記延伸を行うにあたっては、フィルム厚みを均一にするための種々の工夫を施すのが望ましい。フィルム厚みを均一にすれば、フィルム走行中の蛇行を抑制できるため、フィルムの加工性を高めることができる。またフィルム印刷時に、部分的に印刷が抜けてしまうのを防止できる。
【０１０６】
フィルム厚みを均一にする手段としては、例えば、（１）延伸温度の制御、（２）延伸に伴う内部発熱の抑制、（３）予備加熱（予熱）条件の制御、（４）延伸の際のフィルム表面温度の均温化などが挙げられる。
【０１０７】
（１）延伸温度の制御
延伸温度を制御する場合、延伸温度が高くなり過ぎないように制御する。延伸温度が高すぎると、フィルム厚み分布値が大きくなり過ぎる場合がある。なお延伸温度が高すぎると、この熱収縮性フィルムから得られたラベルを容器に高速装着する際にラベルの腰の強さが不足する場合もある。
【０１０８】
延伸温度は、例えば、ガラス転移温度（Ｔｇ）＋４０℃以下（好ましくはＴｇ＋１５℃以下）に制御するのが望ましい。
【０１０９】
なお厚みの均一性との関連は小さいが、前記延伸温度は、ガラス転移温度（Ｔｇ）−２０℃以上（好ましくはＴｇ−５℃以上）とするのが望ましい。延伸温度が低すぎると、フィルムの熱収縮率が不足する場合があり、さらにはフィルムの透明性が低下する場合がある。
【０１１０】
（２）延伸に伴う内部発熱の抑制
延伸に伴うフィルムの内部発熱を抑制すると、延伸方向（幅方向など）のフィルム温度斑を小さくでき、延伸後のフィルム（熱収縮性フィルム）の厚みの均一性を高めることができる。
【０１１１】
前記内部発熱を抑制するためには、加熱条件を適宜制御して（例えば、熱風の供給速度を速くして）フィルムを加熱し易くするのが望ましい。加熱不足の部分があると延伸配向に伴う内部発熱が発生するのに対して、フィルムが十分に加熱されていると延伸時に分子鎖が滑りやすくなるため、内部発熱が発生しにくくなる。
【０１１２】
前記加熱条件は熱伝達係数で示すと、例えば、０．００３８Ｊ／ｃｍ²・ｓｅｃ・℃（０．０００９カロリー／ｃｍ²・ｓｅｃ・℃）以上、好ましくは０．００５４〜０．００８４Ｊ／ｃｍ²・ｓｅｃ・℃（０．００１３〜０．００２０カロリー／ｃｍ²・ｓｅｃ・℃）程度である。
【０１１３】
（３）予備加熱（予熱）条件の制御
予備加熱条件を制御する場合、フィルムを徐々に加熱するように制御するのが望ましい。予備加熱工程でフィルムを徐々に加熱すると、フィルムの温度分布を略均一にできるため、延伸後のフィルム（熱収縮性フィルム）の厚みの均一性を高めることができる。
【０１１４】
前記加熱条件は熱伝達係数で示すと、例えば、０．００５４４Ｊ／ｃｍ²・ｓｅｃ・℃（０．００１３カロリー／ｃｍ²・ｓｅｃ・℃）以下程度である。また予備加熱では、フィルム表面温度がＴｇ＋０℃〜Ｔｇ＋６０℃の範囲内の温度になるまで加熱するのが好ましく、熱風の温度はＴｇ＋１０℃〜Ｔｇ＋９０℃程度であるのが好ましい。
【０１１５】
前記熱伝達係数を達成する方法としては、例えば、熱風の供給速度を遅くする方法などが挙げられる。
【０１１６】
（４）延伸の際のフィルム表面温度の均温化
フィルムを延伸するに際してフィルムの表面温度の変動幅を小さくする（均温化する）と、フィルム全長に亘って同一温度で延伸や熱処理することができる。そのため厚みの均一性を高めることができ、さらにはフィルムの熱収縮挙動を均一にすることもできる。
【０１１７】
前記表面温度の変動幅は、任意のポイントにおいてフィルムの表面温度を測定したときの各ポイントの温度が、例えば、フィルムの平均温度±１℃以内程度であることが好ましく、平均温度±０．５℃以内であることがさらに好ましい。
【０１１８】
フィルムを延伸する際には、延伸前の予備加熱工程、延伸工程、延伸後の熱処理工程、緩和処理、再延伸処理工程などの種々の工程を経てフィルムを延伸するため、これらの工程の一部又は全部で、フィルムの表面温度の変動幅を小さくできる（均質化する）設備を用いるのが好ましい。特に、フィルム全長に亘って厚みを均一にするためには、予備加熱工程及び延伸工程において（さらに、必要に応じて延伸後の熱処理工程において）、フィルムの表面温度の変動幅を小さくできる設備を用いるのが好ましい。なお熱収縮率挙動を均一にする場合には、延伸工程において、フィルムの表面温度の変動幅を小さくできる設備を用いるのが好ましい。
【０１１９】
前記フィルム表面温度の変動を小さくできる設備としては、例えば、フィルムを加熱するための熱風の供給速度を制御するための風速制御手段（インバーターなど）を備えた設備、空気を安定的に加熱して前記熱風を調製するための加熱手段［５００ｋＰａ以下（５ｋｇｆ／ｃｍ²以下）の低圧蒸気を熱源とする加熱手段など］を備えた設備などが挙げられる。
【０１２０】
延伸によって得られる熱収縮性フィルムの厚みは特に限定されないが、例えば、ラベル用途に使用する場合、１０〜２００μｍ程度、好ましくは２０〜１００μｍ程度である。
【０１２１】
そして前記熱収縮性フィルムを巻取りコア（芯）に巻き取ることにより、本発明の熱収縮性フィルムロールを製造できる。フィルムロールに巻き取るフィルムは、幅２００ｍｍ以上、長さ３００ｍ以上であるのが好ましい。幅が２００ｍｍ以上とするのは、フィルムロールの工業的な利用価値を高めるためである。また長さが３００ｍ以上とするのは、フィルムの巻長が長い程、フィルムの流れ方向に熱的特性（ガラス転移温度など）が変動しやすくなるためであり、このような場合に、熱的特性の変動を抑制する本発明を有効性を高めることができる。
【０１２２】
ロールに巻回される熱収縮性フィルムの幅は、好ましくは３００ｍｍ以上、さらに好ましくは４００ｍｍ以上である。またロールに巻回される熱収縮性フィルムの長さは、好ましくは４００ｍ以上、さらに好ましくは５００ｍ以上である。
【０１２３】
前記フィルムの幅の上限は特に制限されないが、取扱いのしやすさから、一般的には幅１５００ｍｍ以下である。また前記フィルムの長さの上限も特に制限されないが、取り扱いのしやすさから、フィルム厚みに応じて上限を定めてもよく、例えばフィルム厚み４５μｍの場合、フィルム長さは６０００ｍ以下が好ましい。
【０１２４】
巻取りコアとしては、通常、プラスチックコアや金属製コアを使用できる。これらコアの径は、例えば、２〜１０インチ程度（例えば、３インチ、６インチ、８インチなど）である。
【０１２５】
上述のようにして得られた本発明の熱収縮性フィルムロールは、原料偏析が抑制されているため、フィルムの流れ方向に熱的特性（ガラス転移温度、結晶化温度、融解温度など、特にガラス転移温度）、及び３次元表面粗さＳＲｚが安定している。
【０１２６】
このようなフィルムロールは、収縮包装、収縮ラベル、キャップシールなどの用途に広く使用できるが、本発明のフィルムロールは、チューブ化した後、裁断することによって熱収縮性ラベルを製造するときの裁断性に優れており、しかも容器側面全体を被覆するためのフルラベルを製造して容器に熱収縮させ、このフルラベル化容器を高温のままで梱包したときの耐ブロッキング性にも優れているため、収縮ラベル（好ましくはフルラベル）に使用するのが特に有用である。
【０１２７】
【実施例】
以下、実施例を挙げて本発明をより具体的に説明するが、本発明はもとより下記実施例によって制限を受けるものではなく、前・後記の趣旨に適合し得る範囲で適当に変更を加えて実施することも勿論可能であり、それらはいずれも本発明の技術的範囲に包含される。なお実施例、比較例、及び参考例で使用するチップ及びフィルムロールの組成及び物性の測定方法は、以下の通りである。
【０１２８】
（１）定常領域の確認と試料切り出し部の設定
後述する実施例、比較例、及び参考例で得られた長さ１０００ｍのフィルムが巻回されたフィルムロールについて、フィルムの第２端部（巻き終り部）から２０ｍ間隔で５点試料を切出し、フィルムの第１端部（巻き始め部）から２００ｍ内側の部分から前記第１端部に向けて２０ｍ間隔で５点の試料を切出し、これら試料の最大収縮方向の最大熱収縮応力値を測定した（後述）。各試料の最大熱収縮応力値は、３ＭＰａ以内の幅に収まっていた。しかもフィルムの製造中、製造・延伸工程は安定していた。従って各フィルムロールは、フィルムの全長に亘って定常領域に該当していることが確認された。
【０１２９】
このようなフィルムロールにおいて、定常領域から試料を切り出し、下記各物性を測定した。すなわち下記物性（３）「溶剤接着強度」、（６）「収縮仕上がり性」、（１０）「裁断性」、（１１）〜（１３）「ブロッキング性」、（１４）「走行性及び耐削れ性」以外の測定においては、１番目の試料切り出し部をフィルムの第２端部（巻き終わりから０ｍ）とし、最終の試料切り出し部は、フィルムの第１端部（巻き始めから０ｍ）とし、全部で１１箇所の試料切り出し部から試料を採取した。そして各試料切り出し部から１０個の試料を切り出し、各試料切り出し部における１０個の試料の物性の平均値を、その切り出し部における試料の物性値とした［なお、（３）「溶剤接着強度」、（６）「収縮仕上がり性」、（１０）「裁断性」、（１１）〜（１３）「ブロッキング性」、（１４）「走行性及び耐削れ性」の場合については、各測定項目のところで詳述する］。
【０１３０】
（２）成分組成
各試料（チップ又はフィルム）を、クロロホルムＤ（ユーリソップ社製）とトリフルオロ酢酸Ｄ１（ユーリソップ社製）を１０：１（体積比）で混合した溶媒に溶解させて、試料溶液を調製し、ＮＭＲ（「ＧＥＭＩＮＩ−２００」；Ｖａｒｉａｎ社製）を用いて、温度２３℃、積算回数６４回の測定条件で試料溶液のプロトンのＮＭＲを測定した。ＮＭＲ測定によるプロトンのピーク強度に基づいて、試料を構成するモノマーの構成比率を算出した。ＮＭＲ測定では、所定のプロトンのピーク強度を算出して、多価アルコール成分１００モル％中のエチレングリコール量、ネオペンチルグリコール量、または１，４−ブタンジオール量を測定した。下記実施例及び比較例において最も多いアルコール成分はエチレングリコールであった。このエチレングリコール以外の成分のうち、最も多いアルコール成分（最多副次的アルコール成分）、及び２番目に多いアルコール成分（第２副次的アルコール成分）の含有率の試料間の変動（平均値、最大値、最小値）を調べた。
【０１３１】
（３）溶剤接着強度
フィルムロール（長さ１０００ｍ）のフィルムを全長に亘って幅２７３ｍｍにスリットして、再びロール状に巻回し、温度３０±１℃、相対湿度８５±２％に制御した環境内に２５０時間保管した。続いて、これに東洋インキ製造社製の草色、金色、白色のインキで３色印刷した後、チューブ成形装置を用い、フィルムの両スリット端のうち片端に、端縁部分には付着しないようにして１，３−ジオキソランを２±１ｍｍ幅で片面塗布し（塗布量：３．０±０．３ｇ／ｍｍ²）、直ちにフィルムを折り曲げて両スリット端部を重ね合わせて接着し、チューブに加工した（加工速度：８０ｍｍ／分）。このチューブを平らに潰した状態で巻き取ってロール状とした。
【０１３２】
上記のチューブロールから、約１００ｍ間隔で試料を切り出す。１番目の試料切り出し部は、チューブの巻き終わり部分（巻き終わりから０ｍ）とする。また、最終の切り出し部は、チューブの巻き始め部分（巻き始めから０ｍ）とし、全部で１１の試料を採取した。各試料切り出し部から得たチューブ状試料を、接着箇所が中央になるように切り開いて、フィルム状試料とした。このフィルム状試料から、長さ１００ｍｍ、幅１５ｍｍのフィルム状試験片（ｎ＝１０）を切り出して、このフィルム状試験片を、チャック間距離を５０ｍｍにセットした引張試験機（ボールドウイン社製「ＳＴＭ−Ｔ」）に、溶剤接着部がチャック同士の中央に位置するようにセットして、温度２３℃、引張速度２００ｍｍ／分の条件で引張試験を行い、接着部分の剥離強度を測定し、これを溶剤接着強度とする。なお各試料切り出し部から１０個の試料を切り出し、各試料切り出し部における１０個の試料の溶剤接着強度の平均値を、その切り出し部における試料の溶剤接着強度とした。
【０１３３】
上記溶剤接着強度の試料間の変動（平均値、最大値、最小値）を調べた。
【０１３４】
（４）熱的特性（ガラス転移温度、結晶化温度、融解温度）
セイコー電子工業（株）製のＤＳＣ装置（型式：ＤＳＣ２２０）を用い、上述の方法に従って、全ての試料の熱的特性（ガラス転移温度、結晶化温度、融解温度）を測定した。
【０１３５】
上記熱的特性の試料間の変動（平均値、最大値、最小値）を調べた。
【０１３６】
（５）最大収縮方向の熱収縮率
フィルムを長手方向およびその直交方向に沿うように１０ｃｍ×１０ｃｍの正方形に裁断し、８５℃±０．５℃の温水中に、無荷重状態で１０秒間浸漬して熱収縮させた後、直ちに２５℃±０．５℃の水中に１０秒浸漬した後、試料の縦および横方向の長さを測定し、下記式に従って求めた。
熱収縮率（％）＝１００×（収縮前の長さ−収縮後の長さ）÷（収縮前の長さ）
最も収縮率の大きい方向を最大収縮方向とした。
【０１３７】
上記最大収縮方向の熱収縮率の試料間の変動（平均値、最大値、最小値）を調べた。
【０１３８】
（６）フルラベル形成時の収縮仕上り性
上記（３）「溶剤接着強度」測定において使用したサンプリング後のチューブロールを、再使用する。すなわち長さ１０００ｍのチューブロールに約１００ｍ間隔で形成されたサンプリング部においてチューブロールを切断し、長さ１００ｍのチューブを１０本作成し、さらに１００ｍチューブの両端に残存するサンプリング部を切り落として、１００ｍチューブの形を整えた。１０本の１００ｍチューブのうち７本を、間隔１６ｃｍで裁断することによって、フルラベル用の熱収縮性ラベルを作成した。得られた熱収縮性フルラベル全量に対して、以下の収縮仕上がり性試験を行った。すなわち、容量３００ｍｌの密栓可能なガラス瓶に熱収縮性フィルムラベルを装着して、フジ・アステック社製のスチームトンネル（型式：ＳＨ−１５００−Ｌ）に、トンネル通過時間１０秒、１ゾーン温度／２ゾーン温度＝８０℃／９０℃の条件で通過させ、前記ガラス瓶の側面全体と栓の一部までを前記熱収縮性フルラベルで被覆した。
【０１３９】
不具合（シワの発生、ラベル端部の折れこみ、色斑、収縮不足）の有無を目視で判断し、収縮仕上がり性を５段階で評価した。基準は、５：仕上がり性最良、４：仕上がり性良、３：不具合が少し有り（２ヶ所以内）、２：不具合有り（３〜５ヶ所）、１：不具合多い（６ヶ所以上）として、４以上を合格、３以下を不合格とした。そして下記式に基づいて不良率を算出した。
【０１４０】
不良率＝（不合格のラベルの数）÷（全てのラベルの数）×１００ （％）
（７）最大熱収縮応力値
最大収縮方向の長さが２００ｍｍ、幅２０ｍｍの試料を用意し、熱風式加熱炉を備えた引張試験機（東洋精機製「テンシロン」）の加熱炉内を９０℃に加熱しておき、送風を止め、加熱炉内に試料をセットする。チャック間距離は１００ｍｍ（一定）とする。加熱炉の扉を速やかに閉めて、送風（９０℃、吹き出し速度５ｍ／ｓ）を再開し、熱収縮応力を検出・測定する。チャートから最大値を読み取り、これを最大熱収縮応力値（ＭＰａ）とした。
【０１４１】
上記最大熱収縮応力値の試料間の変動（平均値、最大値、最小値）を調べた。
【０１４２】
（８）最大収縮方向と直交する方向における熱収縮率
前記（５）の最大収縮方向の熱収縮率の測定において、最大収縮方向に直交する方向においても熱収縮率を求めた。
【０１４３】
上記直交方向の熱収縮率の試料間の変動（平均値、最大値、最小値）を調べた。
【０１４４】
（９）３次元表面粗さＳΔａ、ＳＲｚ
サンプリングした試料の表面を、フィルムロールの長手方向に沿って触針（測定長１ｍｍ、カットオフ値０．２５ｍｍ）した。なお前記触針は、触針式３次元粗さ計（ＥＴ−３０Ｋ、株式会社小坂製作所製）を用いた（針半径２μｍ、荷重３０ｍｇ）。前記触針によって得られた長さ１ｍｍの凹凸プロフィールを２μピッチで５００点に分割し、各店の高さを３次元粗さ解析装置（ＡＴ−３０Ｋ、株式会社小坂製作所製）に取り込ませた。
【０１４５】
上記と同様の操作を、フィルムロールの幅方向に２μｍ間隔で、連続的に１５０回（すなわちフィルムの幅方向０．３ｍｍに亘って）行った。そして前記解析装置に計算させることにより、３次元表面粗さＳΔａ及びＳＲｚを求めた。
【０１４６】
上記３次元表面粗さＳΔａ、ＳＲｚの試料間の変動（最大値、最小値）を調べた。
【０１４７】
（１０）裁断性（不良率）
前記（６）「収縮仕上がり性」評価のときに作成した１０本の１００ｍチューブのち１本を裁断して、裁断性（不良率）を評価した。より詳細には、前記チューブを速度１０ｍ／分で送り出しながら、該チューブのうち印刷が施されていない部分を裁断機で連続的に裁断し（裁断間隔＝約８ｃｍ）、８ｃｍラベルを製造した。裁断部を手で開口し、裁断性を３段階で評価した。基準は、○：抵抗なく開口できる、△：開口時に抵抗あり、×：開口時の抵抗大または開口不能として、○を合格とした。そして下記式に基づいて不良率を算出した。
【０１４８】
不良率＝（不合格のラベルの数）÷（全てのラベルの数）×１００ （％）
（１１）ホットウォーム保管時のフルラベルのブロッキング発生率
前記（６）「収縮仕上がり性」試験において得られたフルラベル化したガラス瓶を用いる。収縮仕上がり試験直後では、このフルラベル化ガラス瓶の表面は高温となっている。そして試験直後のフルラベル化ガラス瓶のうち約１／２を、ラベル同士が互いに接触するようにして段ボール箱（３×４＝１２個入り）に順次箱詰めした。このダンボール箱を温度５０±１℃に制御した室内に２４時間保管した後取り出し、ラベル同士のブロッキングの程度を３段階で評価した。基準は、○：ブロッキングなし、△：ブロッキングがあるものの、剥離したときに跡が残らない、×：ブロッキングがあり、剥離跡が残るとして、○及び△を合格とした。そして下記式に基づいてブロッキング発生率を算出した。
【０１４９】
ブロッキング発生率＝（不合格のラベルの数）÷（全てのラベルの数）×１００ （％）
（１２）常温保管時のフルラベルのブロッキング発生率
残り約１／２のフルラベル化ガラス瓶を用い、保管温度を約２０℃とする以外は、上記（１１）の「ホットウォーム時のブロッキング発生率」と同様にした。
【０１５０】
（１３）ホットウォーム保管時の部分ラベルのブロッキング発生率
前記（６）「収縮仕上がり性」評価のときに製造した１０本の１００ｍチューブのうち２本を、間隔８ｃｍで裁断することによって、部分ラベル用の熱収縮性ラベルを作成した。この熱収縮性部分ラベルを用い、前記（６）「収縮仕上がり性」評価と同様にして、部分的にラベル化したガラス瓶を製造した。この部分ラベル化ガラス瓶を、前記（１１）「ホットウォーム保管時のフルラベルのブロッキング発生率」と同様に処理することにより、部分ラベルのときのブロッキング発生率を調べた。
【０１５１】
（１４）フィルム走行性及び耐削れ性
前記（３）「溶剤接着強度」とは別に、フィルムを全長に亘って幅１００ｍｍにスリットしてテープ状とした。このテープを巻き取ってロールとした後、このロールからテープを引き出し、０．２ｍ間隔で並ぶ金属製ガイドロールに掛け渡した後、巻き取り用のロールに接続した。そして該テープ全てを速度１００ｍ／分で走行させた。走行後のテープの表面の擦り傷の量及びガイドロールの表面に発生する白粉の量を目視で観察し、下記基準に従って評価した。
【０１５２】
（Ａ）走行性
１級：擦り傷がかなり多い
２級：擦り傷が多い
３級：擦り傷ややあり
４級：擦り傷ほとんどなし
５級：擦り傷なし
（Ｂ）耐削れ性
１級：白粉の発生が非常に多い
２級：白粉の発生が多い
３級：白粉の発生ややあり
４級：白粉の発生ほぼなし
５級：白粉の発生なし
合成例１（ポリエステル系チップの合成）
撹拌機、温度計および部分環流式冷却器を備えたステンレススチール製オートクレーブに、ジカルボン酸エステルとしてのジメチルテレフタレート（ＤＭＴ）と、多価アルコールとしてのエチレングリコール（ＥＧ）及びネオペンチルグリコール（ＮＰＧ）［ＥＧ／ＮＰＧ＝７０／３０（モル比）］を、多価アルコールがモル比でＤＭＴの２．２倍になるように仕込み、エステル交換触媒としての酢酸亜鉛０．０５モル％（酸成分に対して）と、重縮合触媒としての三酸化アンチモン０．０２５モル％（酸成分に対して）を添加した後、生成するメタノールを系外へ留去しながらエステル交換反応を行った。その後、温度２８０℃、圧力２６．７Ｐａ（０．２Ｔｏｒｒ）の減圧条件下で重縮合した。得られた共重合ポリエステルを重合装置よりストランド状で取り出し、直ちに水冷した後、ストランドカッターでカットした。得られたポリエステル系チップ（チップＡ）の固有粘度は０．７０ｄｌ／ｇであり、チップの平均長さは４．０ｍｍ、チップ横断面の平均長径は３．６ｍｍ、平均短径は２．８ｍｍであった。
【０１５３】
合成例２〜４
合成例１と同様な方法により、表１に示すチップＢ〜Ｇを得た。なお、表中、ＤＭＴはテレフタル酸成分を、ＥＧはエチレングリコール成分を、ＢＤはブタンジオール成分を、ＮＰＧはネオペンチルグリコール成分を、ＤＥＧはジエチレングリコール成分を示す。
【０１５４】
また前記チップＣに種々の粒径を有する無機滑材（粒径：０．００７〜５．８μｍ、シリカ粒子）を添加してマスターバッチを調整した（無機滑剤含有量：０．７質量％）。前記マスターバッチは、無機滑材の粒径の点で複数種調整したが、いずれもチップＣと樹脂成分及び形状が共通するため、チップＣ’と総称する。下記の実施例、比較例、及び参考例において、マスターバッチ（チップＣ’）の量を調節することによって、フィルムロール中の無機滑剤の量及び粒径を調製した。
【０１５５】
各チップの特性をまとめると、下記表１の通りである。
【０１５６】
【表１】

【０１５７】
なお上記表１中、極限粘度は以下のようにして求めた。すなわち、そもそも極限粘度は、チップ０．１ｇを精秤し、２５ｍｌのフェノール／テトラクロロエタン＝３／２（質量比）の混合溶媒に溶解した後、オストワルド粘度計で３０±０．１℃で測定した。極限粘度［η］は、下式（Ｈｕｇｇｉｎｓ式）によって求められる。
【０１５８】
【数２】

【０１５９】
ここで、η_sp ：比粘度、ｔ₀：オストワルド粘度計を用いた溶媒の落下時間、ｔ：オスワルド粘度計を用いたチップ溶液の落下時間、Ｃ：チップ溶液の濃度である。なお、実際の測定では、Ｈｕｇｇｉｎｓ式においてｋ＝０．３７５とした下記近似式で極限粘度を算出した。
【０１６０】
【数３】

【０１６１】
ここで、η_r：相対粘度である。
【０１６２】
実施例１
上記合成例で得られた各チップを別個に予備乾燥した。チップＡ、チップＣ、チップＣ’及びチップＤを単軸式押出機直上のホッパーに定量スクリューフィーダーを用いて連続的に別々に供給しながら、このホッパー内で各チップを混合した（チップＡ：６６質量％、チップＣ及びＣ’の合計：９質量％、チップＤ：２５質量％）。この混合チップを押出機を用いて温度２８０℃で溶融押出しし、キャスティングロールで急冷して、厚さ１８０μｍの未延伸フィルムを得た。なお前記ホッパは、チップが約１５０ｋｇ入る容量を有しており、押出機の吐出量は１時間当たり４５０ｋｇである。また、ホッパー側壁の傾斜角は７０°である。
【０１６３】
前記未延伸フィルムを１０００ｍ以上に亘って連続的に延伸した。延伸では、温度１００℃で１０秒間予熱した後、テンターを用いて温度８０℃で横方向に４．０倍延伸し、続いて温度８０℃で１０秒間熱処理を行うことにより、厚さ４５μｍの熱収縮性ポリエステル系フィルムを得た。熱収縮性フィルムを１０００ｍ連続製造したときのフィルム表面温度の変動幅は、予熱工程で平均温度±０．７℃、延伸工程で平均温度±０．５℃、熱処理工程で平均温度±０．５℃の範囲内であった。なおフィルムの表面温度は、赤外式の非接触表面温度計を用いて測定した（以下の実施例、比較例でも同じ）。
得られたフィルムを幅５００ｍｍ、長さ１０００ｍにスリットして、３インチの紙管に巻き取り、熱収縮性フィルムロールを得た。
【０１６４】
比較例１
チップが約４００ｋｇ入る容量を有し、側壁の傾斜角が６０°であるホッパを直列に３個設置し、１段目のホッパにおいて、チップＢ６５質量％、チップＣ及びＣ’の合計１０質量％、及びチップＤ２５質量％を混合した後、２段目のホッパ、及び３段目のホッパを経由して、前記混合チップを単軸式押出機直上のホッパーに供給する以外は、実施例１と同様にして、厚さ４５μｍの熱収縮性ポリエステル系フィルムを製造し、さらに実施例１と同様にして熱収縮性フィルムロールを製造した。
【０１６５】
実施例２
上記合成例で得られた各チップを別個に予備乾燥した。チップＡ、チップＣ、チップＣ’、及びチップＤを単軸式押出機直上のホッパーに定量スクリューフィーダーを用いて連続的に別々に供給しながら、このホッパー内で混合した（チップＡ：５１質量％、チップＣ及びＣ’の合計：２３質量％、チップＤ：２６質量％）。この混合チップを押出機を用いて温度２８０℃で溶融押出しし、キャスティングロールで急冷して、厚さ１８０μｍの未延伸フィルムを得た。なお前記ホッパは、チップが約１００ｋｇ入る容量を有しており、押出機の吐出量は１時間当たり４５０ｋｇである。また、ホッパー側壁の傾斜角は７５°である。
【０１６６】
前記未延伸フィルムを１０００ｍ以上に亘って連続的に延伸した。延伸では、温度１０５℃で１０秒間予熱した後、テンターを用いて温度７５℃で横方向に４．０倍延伸し、続いて温度７５℃で１０秒間熱処理を行うことにより、厚さ４５μｍの熱収縮性ポリエステル系フィルムを得た。熱収縮性フィルムを１０００ｍ連続製造したときのフィルム表面温度の変動幅は、予熱工程で平均温度±０．６℃、延伸工程で平均温度±０．５℃、熱処理工程で平均温度±０．７℃の範囲内であった。得られたフィルムを幅５００ｍｍ、長さ１０００ｍにスリットして、３インチの紙管に巻き取り、熱収縮性フィルムロールを得た。
【０１６７】
比較例２
チップが約４００ｋｇ入る容量を有し、側壁の傾斜角が６０°であるホッパを直列に３個設置し、１段目のホッパにおいて、チップＢ５１質量％、チップＣ及びＣ’の合計２３質量％、及びチップＤ２６質量％を混合した後、２段目のホッパ、及び３段目のホッパを経由して、前記混合チップを単軸式押出機直上のホッパーに供給する以外は、比較例１と同様にして、厚さ４５μｍの熱収縮性ポリエステル系フィルムを製造し、さらに比較例１と同様にして熱収縮性フィルムロールを製造した。
【０１６８】
参考例１
上記合成例で得られた各チップを別個に予備乾燥した。チップＥ、チップＦ、、及びチップＧを単軸式押出機直上のホッパーに定量スクリューフィーダーを用いて連続的に別々に供給しながら、このホッパー内で混合した（チップＥ：６０質量％、チップＦ：２５質量％、チップＧ：１５質量％）。この混合チップを押出機を用いて温度２８０℃で溶融押出しし、キャスティングロールで急冷して、厚さ１８０μｍの未延伸フィルムを得た。なお前記ホッパは、チップが約１００ｋｇ入る容量を有しており、押出機の吐出量は１時間当たり４５０ｋｇである。また、ホッパー側壁の傾斜角は７５°である。
【０１６９】
前記未延伸フィルムを１０００ｍ以上に亘って連続的に延伸した。延伸では、温度１０５℃で１０秒間予熱した後、テンターを用いて温度７８℃で横方向に４．０倍延伸し、続いて温度８０℃で１０秒間熱処理を行うことにより、厚さ４５μｍの熱収縮性ポリエステル系フィルムを得た。熱収縮性フィルムを１０００ｍ連続製造したときのフィルム表面温度の変動幅は、予熱工程で平均温度±０．５℃、延伸工程で平均温度±０．４℃、熱処理工程で平均温度±０．５℃の範囲内であった。得られたフィルムを幅５００ｍｍ、長さ１０００ｍにスリットして、３インチの紙管に巻き取り、熱収縮性フィルムロールを得た。
【０１７０】
上記実施例、比較例、及び参考例におけるチップ配合比と、実施例、比較例、及び参考例で得られた熱収縮性フィルムロールの物性を下記表２〜１３に示す。
【０１７１】
【表２】

【０１７２】
【表３】

【０１７３】
【表４】

【０１７４】
【表５】

【０１７５】
【表６】

【０１７６】
【表７】

【０１７７】
【表８】

【０１７８】
【表９】

【０１７９】
【表１０】

【０１８０】
【表１１】

【０１８１】
【表１２】

【０１８２】
【表１３】

【０１８３】
表９より明らかなように、実施例１〜２、比較例１〜２、及び参考例１のフィルムロールは、いずれも最大収縮方向の熱収縮率が２０％以上であり、熱収縮性を有しているといえる。
【０１８４】
ここで実施例１〜２及び参考例１のフィルムロールは、比較例１〜２のフィルムロールに比べると、表２より明らかなように配合チップの形状が揃っているため、表６より明らかなようにガラス転移温度がフィルムの長手方向で安定している。そのため裁断性に優れる（表１３参照）。なお実施例１〜２及び参考例１のフィルムロールは、最大収縮方向の熱収縮率も安定している（表９参照）。そのため収縮仕上がり性にも優れる（表１３参照）。さらに実施例１〜２及び参考例１のフィルムロールは、最多副次的アルコール成分の含有率、第２副次的アルコール成分の含有率、溶剤接着強度、結晶化温度、融解温度、最大熱収縮応力、及び直交方向の熱収縮率などの点でも安定している（表３〜５，７〜８，１０参照）。
【０１８５】
ところが参考例１のフィルムロールは、３次元表面粗さＳＲｚが小さすぎて（表１２参照）、フルラベルとしたときのホットウォーム保管時の耐ブロッキング性が悪く（表１３参照）、また３次元表面粗さＳΔａが小さすぎて（表１２参照）、走行性（耐傷性）が悪い。なお比較例１のフィルムロールも、３次元表面粗さＳＲｚ及びＳΔａが小さすぎ、フルラベルとしたときのホットウォーム保管時の耐ブロッキング性及び走行性（耐傷性）が悪く、比較例２のフィルムロールは、結晶化温度及び融解温度が不均一であるため（表７〜８参照）、ホットウォーム保管時の耐ブロッキング性が悪く（表１３参照）、また３次元表面粗さＳＲｚが大きすぎるために（表１２参照）、耐削れ性が悪い（表１３参照）。これらに対して、実施例１〜２のフィルムロールは、適量の無機滑材を含有しているため（表２参照）、三次元表面粗さＳΔａ及びＳＲｚが適切な範囲に制御されている（表１２参照）。そのため、容器の側面全体にラベルとして被覆し（フルラベル）、ホットウォーム保管しても耐ブロッキング性に優れ、さらにはフィルムの走行性及び耐削れ性にも優れる（表１３参照）。なお参考例１のフィルムロールであっても、部分ラベルとして使用する場合又は常温で保管する場合には、ボトル被覆後の耐ブロッキング性に問題はない。
【０１８６】
【発明の効果】
本発明によれば、複数種のチップから製造された熱収縮性フィルムロールであっても、フィルムの流れ方向のガラス転移温度及び３次元表面粗さＳＲｚが所定の範囲内に制御されているため、フィルムから加工したチューブを裁断する時の熱融着や裁断性低下を防止でき、さらには前記チューブを裁断したフルラベルを熱収縮によって容器に密着し、得られた製品を高温のままで梱包するときのフルラベル同士のブロッキングを防止することができる。このためフィルムロールの歩留まりを高めることができる。[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a film roll obtained by winding a heat-shrinkable film suitable for label applications.
[0002]
[Prior art]
Heat-shrinkable films are widely used for applications such as shrink wrapping, shrinkage labels, cap seals, etc. by utilizing the property of shrinking by heating. In particular, polyvinyl chloride films, polystyrene films, polyester films, etc. are used for labels, cap seals, and integrated packaging in various containers such as polyethylene terephthalate (PET) containers, polyethylene containers, and glass containers. (For example, refer to Patent Document 1).
[0003]
In many cases, the heat-shrinkable film is given a heat-shrink property by stretching and then wound up and transported or stored in the form of a roll. And when using it for label applications, after drawing the film from the roll and printing the design, etc., it is slit (cut) to an appropriate size, and both sides of this cut film are overlapped and sealed (solvent adhesion, It is processed into a tube by heat sealing. The tube can be further processed by cutting (crossing) into a form that can be attached to the container (a shape having an opening such as a cylindrical label or a bag-like label). More specifically, a cylindrical label can be manufactured by traversing the tube, and a bag-shaped label can be manufactured by sealing one opening of the cylindrical label. However, in the conventional heat-shrinkable film, when the tube is cut, the cut portion (opening portion) may be heat-sealed and may not be attached to the container. In addition, the cutting property is low and a cut mistake may occur. Therefore, it is desired to improve the above-described problems and increase the yield.
[0004]
The label (tubular label, bag-shaped label) is mounted on a container, and then placed on a belt conveyor or the like. For example, a hot-air tunnel), and is heat-shrinked so as to be in close contact with the container. However, conventional heat-shrinkable films may cause poor appearance such as insufficient heat shrinkage and shrinkage spots, which may reduce the yield.
[0005]
Furthermore, a container (labeled container) with a label attached thereto is often packed (boxed or the like) at a high temperature. However, in recent years, there are cases where the label is brought into close contact with the entire side surface of the container (full label). In such a full-labeled container, if the packaging is performed at a high temperature, the labels may adhere to each other (blocking) between the packed containers, and the yield may be reduced.
[0006]
In addition, the said heat-shrinkable film is normally manufactured by forming and extending | stretching, after mixing several types of raw material chip | tips. The reason why the plural kinds of raw material chips are mixed is that the physical properties of the film can be easily prepared according to the use of the label by adjusting the compounding ratio of the chips.
[0007]
[Patent Document 1]
JP 7-138388 A (paragraphs 0001 to 0005)
[0008]
[Problems to be solved by the invention]
The present invention has been made paying attention to the above-mentioned circumstances, and its purpose is not only excellent in cutting properties when manufacturing a heat-shrinkable label by cutting into a tube and then cutting it. An object of the present invention is to provide a heat-shrinkable polyester film roll that is excellent in blocking resistance when a full label is produced and thermally contracted in a container and the full-labeled container is packaged at a high temperature.
[0009]
[Means for Solving the Problems]
As a result of intensive studies to solve the above-mentioned problems, the present inventors have found that the cause of the decrease in cutting property and blocking resistance is the thermal characteristics (glass transition temperature, crystallization temperature, melting temperature, etc.) ) Was found to be unstable. In particular, in a film roll manufactured from a plurality of types of raw material chips, it has been found that the thermal characteristics tend to fluctuate greatly in the film flow direction.
[0010]
For example, when the glass transition temperature fluctuates greatly in the film flow direction, the glass transition temperature fluctuates greatly in the longitudinal direction also in the obtained tube. On the other hand, when the label is manufactured by cutting the tube, the cutting machine gets heated as the operation of the cutting machine continues. And it has been found that the decrease in the cutting property frequently occurs when a portion having a high glass transition temperature is cut. Further, it has been found that the heat fusion at the time of cutting the tube frequently occurs when a portion having a low glass transition temperature is cut. In addition, even if the glass transition temperature is cut, the label may be produced without thermal fusion. I found out.
[0011]
It was also found that even when the crystallization temperature and the melting temperature fluctuate greatly in the film flow direction, troubles (thermal fusion, cut mistakes) and blocking at the time of cutting occur more frequently.
[0012]
Accordingly, if at least the glass transition temperature of the film roll is stabilized (preferably all of the glass transition temperature, the crystallization temperature, and the melting temperature are stabilized), the cutting property and the blocking resistance are achieved. Has been found to be significantly improved.
[0013]
However, the stabilization of the glass transition temperature is not sufficient to meet the recent demand for full labeling. In other words, in an actual production line, full-labeled containers produced by heat shrinkage are still packed while hot to increase productivity. Under such severe conditions, blocking may occur even if the glass transition temperature is stabilized. As a result of further research, the inventors found that controlling the three-dimensional surface roughness SRz of the film surface can suppress the occurrence of blocking even in a fully-labeled container, and completed the present invention.
[0014]
That is, the heat-shrinkable polyester film roll according to the present invention is a film roll formed by winding a heat-shrinkable polyester film, and the film is wound in a steady region where the film physical properties are stable in the length direction of the film. The end on the start side is the first end, the end on the winding end is the second end, the first sample cut-out portion is within 2 m inside the second end, and the first end is When the final cutout portion is provided within 2 m inside and the sample cutout portion is provided about every 100 m from the first sample cutout portion, the following requirements (1), (2) and (3) are satisfied. It has a gist.
[0015]
(1) About each sample of 10 cm x 10 cm square shape cut out from each sample cut-out part, each sample was dipped in hot water at 85 ° C for 10 seconds and then dipped in water at 25 ° C for 10 seconds and pulled up. When the thermal shrinkage rate in the maximum shrinkage direction is 20% or more for all samples
(2) When the glass transition temperature is measured for the sample cut out from each sample cutting section, the glass transition temperature of each sample is within ± 4 ° C. of the average value of the glass transition temperatures of all the samples.
(3) When the three-dimensional surface roughness SRz is measured for the sample cut out from each of the sample cutout portions, the three-dimensional surface roughness SRz of all the samples is in the range of 0.6 to 1.5 μm.
It is desirable that the film roll further satisfies the following requirement (4).
[0016]
(4) When the three-dimensional surface roughness SΔa is measured for the samples cut out from the respective sample cutout portions, the three-dimensional surface roughness SΔa of all the samples is in the range of 0.008 to 0.04.
The heat-shrinkable film roll usually contains a lubricant having an average particle size of 0.01 to 3 μm in a range of 0.02 to 0.5% by mass. The heat-shrinkable film is usually obtained by mixing a plurality of types of raw material chips having different glass transition temperatures, followed by film formation and stretching.
[0017]
Desirably, the film roll is substantially amorphous. In the case of crystallinity, it is desirable that the crystallization temperature is 100 ° C. or higher and further satisfies the following requirement (5).
[0018]
(5) When the crystallization temperature is measured for the sample cut out from each of the cutout portions, the crystalline film roll in which the crystallization temperature of each sample is within ± 5 ° C. of the average value of the crystallization temperature of all the samples is It is particularly desirable that the melting temperature is 180 to 230 ° C. and the following requirement (6) is satisfied.
[0019]
(6) When the melting temperature is measured for the sample cut out from each cutout part, the melting temperature of each sample is within ± 5 ° C. of the average value of the melting temperatures of all the samples.
The film roll of the present invention is obtained, for example, by winding a film having a width of 200 mm or more and a length of 300 m or more.
The present invention is a method for producing a heat-shrinkable polyester film roll comprising a step of mixing a polymer having the largest amount of use and one or more other polymers having different compositions from each other and melt-extruding the polymer. ,
The shape of the raw material chip of each polymer used is an elliptical column having an elliptical cross section having a major axis and a minor axis, and the raw material chip of the polymer other than the most used polymer is replaced with the raw material chip of the most used polymer. The average major axis (mm), average minor axis (mm), average minor axis (mm), and average tip length (mm) included in a range within ± 20% of the average major axis (mm), average minor axis (mm), and average tip length (mm), respectively. (Mm)
Further, a lubricant having a particle diameter of 0.01 to 4 μm is put in at least one raw material chip, and the amount of the lubricating material in the film roll obtained by mixing the raw material chips is 0.02 to 0.5% by mass. The manufacturing method of the heat-shrinkable polyester film roll characterized by controlling to the range is also included.
[0020]
In the present specification, the term “unstretched film” includes a film on which a tension necessary for film feeding is applied.
[0021]
DETAILED DESCRIPTION OF THE INVENTION
[Heat-shrinkable polyester film roll]
The object of the present invention is a polyester-based heat-shrinkable film roll. This is because good heat shrinkage characteristics are exhibited in a wide temperature range from low temperature to high temperature, and an excellent shrink-finished appearance with less shrinkage spots, wrinkles and distortion can be obtained. It also has a beautiful gloss and transparency.
[0022]
The heat-shrinkable polyester film roll of the present invention is obtained by winding a heat-shrinkable polyester film, and in a steady region where film physical properties are stable in the length direction (flow direction) of the film, The transition temperature and the three-dimensional surface roughness SRz are much more stable. By significantly stabilizing these, the cutting property and the anti-blocking property can be improved. Hereinafter, these points will be described in detail.
[0023]
First, the meaning of “a steady region in which film properties are stable in the length direction of the film” will be described. The “steady region where the film physical properties are stable in the length direction of the film” is a region where the film physical properties are almost uniform because the film forming process and the stretching process are stably performed during film production. In the present invention, the glass transition temperature and the three-dimensional surface roughness SRz are made highly uniform in the film roll (long film) obtained when the film forming process and the stretching process are operated in a stable steady state. This is the technical idea. In actual operation, film properties may vary depending on the raw material supply method and film forming conditions during film production, but in the present invention, even when the film forming process and stretching process are unstable, the film is obtained. It does not require homogenization. That is, it is only necessary that the glass transition temperature and the three-dimensional surface roughness SRz are highly uniform only in the “steady region”.
[0024]
<Glass transition temperature>
That is, the heat-shrinkable polyester film roll of the present invention has a uniform glass transition temperature (Tg) at a high level in the film flow direction in the steady region. When the glass transition temperature is uniform, a single film roll is slit to form a tube, and this tube is cut to produce a plurality of identical labels (tubular labels, bag-like labels, etc.) Furthermore, the glass transition temperature can be made uniform in the longitudinal direction of the tube. Therefore, it is possible to prevent thermal fusion of the cut portion (that is, the opening portion of the label) that occurs when the glass transition temperature is low, to prevent defective opening of the label, and to prevent cut mistakes that occur when the glass transition temperature is high, yield. Can be increased.
[0025]
The uniformity of the glass transition temperature in the steady region is as follows: the end on the winding start side of the film in the steady region is the first end, the end on the winding end is the second end, and 2 m inside the second end. When the first sample cut-out portion is provided, the final cut-out portion is provided within 2 m inside the first end portion, and the sample cut-out portion is provided every about 100 m from the first cut-out portion. The sample can be evaluated by measuring the glass transition temperature of the sample cut out from each location (“about every 100 m” means that the sample may be cut out at about 100 m ± 1 m). . The sampling method will be described in more detail. For example, when a heat-shrinkable film having a length of 498 m, whose film physical properties are stable over the entire length of the film, is wound on a roll, the first sample (1) between the end of film winding and within 2 m. Cut out. Subsequently, a second sample {circle around (2)} is cut at a distance of about 100 m from the cut portion. Similarly, the third sample {circle around (3)} is cut at about 200 m, the fourth sample {circle around (4)} is cut at about 300 m, and the fifth sample {circle around (5)} is cut at about 400 m. Here, since the remainder becomes shorter than 100 m, the sixth (final) sample {circle around (6)} cuts out any portion within 2 m from the start of film winding.
[0026]
In the film roll of the present invention, when the average value of the glass transition temperature of all the samples is calculated, the glass transition temperature of the sample at each location is, for example, within ± 4 ° C. of the average value (preferably within ± 3 ° C., further It is preferably made uniform so as to be within ± 2 ° C. That is, the absolute value (| Tn−Tav |) of the difference between the glass transition temperature Tn (° C.) of each sample cut out from the cutout portion and the average glass transition temperature Tav (° C.) of all samples is, for example, 4 ° C. or less. (Preferably 3 ° C. or lower, more preferably 2 ° C. or lower). In other words, the difference between the maximum value (Tmax) of Tn and Tav, and the difference between the minimum value (Tmin) of Tn and Tav are both within ± 4 ° C. (preferably within ± 3 ° C., more preferably ± If it is within 2 ° C.), the above requirement is satisfied.
[0027]
The glass transition temperature (Tg) was determined by heating 10 ± 1 mg of the sample cut from the film at a temperature of 300 ° C. for 2 minutes, immediately putting it in liquid nitrogen and quenching, and then from the temperature −40 ° C. to 300 ° C. at a rate of 20 ° C./min. The temperature can be measured with a differential scanning calorimeter (DSC) to obtain a heat flow rate curve (DSC curve). The glass transition temperature (Tg) means the intersection of tangent lines drawn before and after the endothermic start curve in the heat flow rate curve.
[0028]
The number of the steady regions (steady operation regions) is usually one place per one film roll (one place over the whole film roll). However, depending on the manufacturing situation, there may be a plurality of locations. In this case, sampling is performed only from the steady region. The steady region can be confirmed, for example, by measuring the maximum heat shrinkage stress value in the maximum shrinkage direction of the film. That is, if the maximum heat shrinkage stress value is within a range of about 3 MPa (the difference between the maximum value and the minimum value of the maximum heat shrinkage stress values of a plurality of samples is within about 3 MPa), Good.
[0029]
Here, the maximum heat shrinkage stress value is measured as follows.
(1) Prepare a sample having a length in the maximum shrinkage direction of 200 mm and a width of 20 mm.
(2) Heat the inside of the heating furnace of a tensile testing machine (for example, “Tensilon” manufactured by Toyo Seiki Co., Ltd.) equipped with a hot air heating furnace to 90 ° C.
(3) Stop air flow and set the sample in the heating furnace. The distance between chucks is 100 mm (constant)
(4) The heating furnace door is quickly closed, air blowing (90 ° C., blowing speed 5 m / s) is resumed from the back of the heating furnace and the left and right outlets, and the heat shrinkage stress is detected and measured.
(5) Read the maximum value from the chart, and use this as the maximum heat shrinkage stress value (MPa)
<Three-dimensional surface roughness SRz>
In the heat-shrinkable polyester film roll of the present invention, the three-dimensional surface roughness (three-dimensional ten-point average roughness) SRz is controlled within a predetermined range in the steady region. When the three-dimensional surface roughness SRz is too small, a full label is produced from a film roll and thermally contracted to the container, and the blocking resistance when the fully labeled container is packed at a high temperature is lowered. On the other hand, if the three-dimensional surface roughness SRz is too large, not only the transparency is lowered, but also when the film or the like is pulled out from the film roll for running, the abrasion resistance characteristic is reduced and white powder is generated. Cause.
[0030]
In the heat-shrinkable polyester film roll of the present invention, when the three-dimensional surface roughness SRz was measured for samples cut out every about 100 m from the steady region in the same manner as described above, the three-dimensional surface roughness SRz of all samples was 0. 0.6 μm or more (preferably 0.65 μm or more, more preferably 0.7 μm or more) and 1.5 μm or less (preferably 1.3 μm or less, more preferably 1 μm or less).
[0031]
The three-dimensional surface roughness SRz is the average of the measurement results obtained by measuring the ten-point average roughness Rz in the film flow direction at 150 points set at intervals of 2 μm in the width direction of the film roll. Say things.
[0032]
<Heat shrinkage in maximum shrinkage direction>
The film roll of the present invention also has a predetermined heat shrinkability. This heat shrinkability can be evaluated by the heat shrinkage rate. In the case of the film roll of the present invention, a sample cut out in a 10 cm × 10 cm square shape from the film forming this roll is immersed in warm water at 85 ° C. for 10 seconds. Then, the heat shrinkage rate in the maximum shrinkage direction when it is immediately dipped in water at 25 ° C. for 10 seconds and pulled up needs to be 20% or more. When the film has a heat shrinkage ratio of less than 20%, the film has a short heat shrinkage when it is shrunk on a container or the like, resulting in poor appearance. A more preferable heat shrinkage rate is 30% or more, and further preferably 40% or more. The upper limit of the heat shrinkage rate is preferably 80% (particularly 75%).
[0033]
The “maximum shrinkage direction” means the direction in which the sample is most contracted, and the thermal shrinkage rate in the maximum shrinkage direction is determined by the shrinkage rate in the vertical direction or the horizontal direction (or oblique direction) of the square sample. It is done. That is, the heat shrinkage rate (%) in the maximum shrinkage direction is obtained by immersing a sample of 10 cm × 10 cm in hot water at a temperature of 85 ° C. ± 0.5 ° C. for 10 seconds under no load, followed by heat shrinkage, followed by a temperature of 25 ° C. ± After immersing in 0.5 ° C. water under no load for 10 seconds, the film can be determined according to the following formula by measuring the length in the vertical and horizontal directions (and oblique directions).
[0034]
Heat shrinkage rate = 100 × (length before shrinkage−length after shrinkage) ÷ (length before shrinkage)
In addition, for the sake of convenience, the square cutting direction is cut so as to have a side along the longitudinal direction of the film and a side along the direction orthogonal to the longitudinal direction (not cut diagonally).
[0035]
By the way, also in parts other than the above-mentioned steady region, unless the film production process becomes extremely unstable, the thermal shrinkage rate in the maximum shrinkage direction is within the predetermined range. However, an object of the present invention is to improve the cutting property and blocking resistance of the film in the steady region by making the glass transition temperature and the three-dimensional surface roughness SRz uniform in the steady region. Therefore, it is sufficient that the thermal shrinkage rate in the maximum shrinkage direction is within a predetermined range at least in the steady region.
[0036]
Therefore, in the present invention, the heat shrinkage rate in the maximum shrinkage direction is measured based on each 10 cm × 10 cm square sample cut out from the cutout portion in the steady region, and the heat shrinkage rate is measured for all the samples. In this case, it is sufficient that the predetermined value is reached.
[0037]
<Three-dimensional surface roughness SΔa>
In the present invention, it is desirable that the three-dimensional surface roughness (three-dimensional average slope) SΔa is also controlled within a predetermined range in the steady region. If the three-dimensional surface roughness SΔa is too small, the running property of the film is lowered, and the film surface may be damaged during running. On the other hand, if the three-dimensional surface roughness SΔa is too large, the abrasion resistance characteristic is deteriorated, and white powder is generated when the film travels, which causes printing omission.
[0038]
In the heat-shrinkable polyester film roll of the present invention, when the three-dimensional surface roughness SΔa was measured for samples cut out from the steady region every about 100 m in the same manner as described above, the three-dimensional surface roughness SΔa of all samples was 0. 0.008 or more (preferably 0.01 or more, more preferably 0.012 or more) and 0.04 or less (preferably 0.035 or less, more preferably 0.03 or less).
[0039]
The three-dimensional surface roughness SRz is a measurement result obtained by measuring an average slope Δa defined by the following formula in the film flow direction at 150 points set at intervals of 2 μm in the width direction of the film roll. Means the average of
[0040]
[Expression 1]

[0041]
[Where, f (x) represents a cross-sectional curve, and more specifically, the size of the unevenness at the coordinate x set in the measurement direction (positive when higher than the average line, negative when lower than the average line) ). L indicates the measurement length]
<Crystallinity>
In the film roll of the present invention, the film wound around the roll may be substantially amorphous or may be substantially crystalline. When an amorphous film is used, shrinkage inhibition at the crystal portion does not occur, so that appearance defects during heat shrinkage can be prevented even when the heat shrinkage rate of the film is increased. For this reason, it is particularly suitable for a full label (a label for covering the entire container) where a high heat shrinkage rate is required. In many cases, the heat shrinkability at low temperatures is also excellent. Therefore, when a high heat shrinkage rate or low temperature heat shrinkability is required, it is desirable to use an amorphous film, and in general applications where high heat shrinkage rate or low temperature heat shrinkability is not required, It is desirable to use a crystalline film.
[0042]
The term “substantially crystalline” means that when the film is rapidly cooled from a molten state and then slowly heated at a predetermined rate (for example, about 20 ° C./min), an exothermic peak accompanying crystallization and melting The endothermic peak associated with is observed, and substantially amorphous means that the exothermic peak and endothermic peak are not observed.
[0043]
<Crystalization temperature>
On the other hand, when the film is substantially crystalline, the crystallization temperature of the film is desirably 100 ° C. or higher (preferably 110 ° C. or higher). If the crystallization temperature is too low, crystallization may occur when the film (label) is heated and thermally contracted, and the durability of the shrinkage stress may be reduced. For this reason, it is difficult to relieve shrinkage spots generated during shrinkage, and the finished appearance may be deteriorated. The upper limit of the crystallization temperature is not particularly limited, but is, for example, about 150 ° C. or less, preferably about 145 ° C. or less.
[0044]
Furthermore, it is desirable that the crystallization temperature (° C.) is also made uniform at a high level in the flow direction of the film in the steady region, like the glass transition temperature (Tg). If the crystallization temperature is made uniform, troubles during cutting (thermal fusion, cut mistakes) and blocking of labels can be further suppressed. In addition, the relaxation of the shrinkage spots can be stabilized, and the yield can be prevented from being lowered due to poor appearance.
[0045]
The uniformity of the crystallization temperature can be evaluated by measuring the crystallization temperature of the sample from each cut-out location provided in the same manner as when measuring the glass transition temperature (Tg). In the film roll of the present invention, when the average value of the crystallization temperatures of all the samples is calculated, the crystallization temperature of the sample at each location is, for example, within ± 5 ° C. (preferably within ± 4 ° C. It is desirable to make it uniform so that it is preferably within ± 3 ° C. That is, the absolute value (| Cn−Cav |) of the difference between the crystallization temperature Cn (° C.) of each sample and the average glass transition temperature Cav (° C.) of all samples is, for example, 5 ° C. or less (preferably 4 ° C. or less). And more preferably 3 ° C. or less). In other words, the difference between the maximum value of Cn (Cmax) and Cav, and the difference between the minimum value of Cn (Cmin) and Cav are both within ± 5 ° C. (preferably within ± 4 ° C., more preferably ± If it is within 3 ° C.), the above requirement is satisfied.
[0046]
As for the crystallization temperature, 10 ± 1 mg of the sample cut from the film is heated at 300 ° C. for 2 minutes, immediately put in liquid nitrogen and rapidly cooled, and then the temperature is increased from −40 ° C. to 300 ° C. at a rate of 20 ° C./min. It can be measured by obtaining a heat flow rate curve (DSC curve) with a differential scanning calorimeter (DSC). The crystallization temperature means a temperature indicating the maximum value of the exothermic peak in the heat flow rate curve.
[0047]
<Melting temperature>
Further, when the film is substantially crystalline, the melting temperature of the film is desirably 180 ° C. or higher (preferably 185 ° C., more preferably 195 ° C. or higher). Whereas the crystalline film is excellent for high shrinkage applications and low temperature shrinkage applications, a crystalline film having a high melting temperature is heat shrinkable even at high temperatures and has excellent versatility. If the melting temperature is too high, the sealing performance (heat sealability, solvent adhesiveness, etc.) at the time of label processing is lowered, or the heat shrinkage rate is lowered and the finished appearance after label shrinkage is lowered. Therefore, the melting temperature of the film is usually 230 ° C. or lower (preferably 225 ° C. or lower, more preferably 220 ° C. or lower).
[0048]
Further, it is desirable that the melting temperature (° C.) is also made uniform at a high level in the film flow direction, like the glass transition temperature (Tg). If the melting temperature is uniform, it is possible to further suppress troubles during cutting (thermal fusion, cut mistakes) and blocking of labels. In addition, it is possible to suppress the deterioration of the sealing property and the heat shrinkage rate (deterioration of the finished appearance) and to prevent the yield from decreasing.
[0049]
The uniformity of the melting temperature can be evaluated by measuring the melting temperature of the sample from each cut-out location provided as in the case of measuring the glass transition temperature (Tg). In the film roll of the present invention, when the average value of the melting temperatures of all the samples is calculated, the melting temperature of the sample at each location is, for example, within ± 5 ° C. (preferably within ± 4 ° C., more preferably within the above average value). It is desirable to make it uniform so that it is within ± 3 ° C. That is, the absolute value (| Mn−Mav |) of the difference between the melting temperature Mn (° C.) of each sample and the melting temperature Mav (° C.) of all samples is, for example, 5 ° C. or less (preferably 4 ° C. or less, more preferably Is equalized to be 3 ° C. or less. In other words, the difference between the maximum value (Mmax) of Mn and Mav, and the difference between the minimum value (Mmin) of Mn and Mav are both within ± 5 ° C. (preferably within ± 4 ° C., more preferably ± If it is within 3 ° C.), the above requirement is satisfied.
[0050]
As for the melting temperature, 10 ± 1 mg of the sample cut out from the film was heated at 300 ° C. for 2 minutes, immediately put into liquid nitrogen and rapidly cooled, and then heated from -40 ° C. to 300 ° C. at a rate of 20 ° C./min. It can be measured by obtaining a heat flow rate curve (DSC curve) with a differential scanning calorimeter (DSC). The melting temperature means a temperature indicating the maximum value of the endothermic peak in the heat flow rate curve.
[0051]
<Polyester film>
The polyester-based heat-shrinkable film wound around the film roll of the present invention having the above-described characteristics is not particularly limited as long as it is a polyester-based film and has heat-shrinkability.
[0052]
As the polyester film (heat-shrinkable polyester film), a film composed of a dicarboxylic acid component and a polyhydric alcohol component can be used. More specifically, the film includes a first dicarboxylic acid component (for example, a terephthalic acid component) and a first polyhydric alcohol component (for example, a terephthalic acid component) that constitute a base unit (for example, a crystalline unit such as polyethylene terephthalate). , An ethylene glycol component, and the like), a second dicarboxylic acid component different from the first dicarboxylic acid component, and / or a second polyhydric alcohol component different from the first polyhydric alcohol component. . Whether the film has crystallinity or thermal properties (thermal shrinkage, glass transition temperature, crystallization temperature, melting) by the second dicarboxylic acid component and / or the second polyhydric alcohol component (preferably the second alcohol component) Temperature).
[0053]
Examples of dicarboxylic acids that form dicarboxylic acid components (first dicarboxylic acid component, second dicarboxylic acid component) include aromatic dicarboxylic acids, ester-forming derivatives thereof, and aliphatic dicarboxylic acids. Examples of the aromatic dicarboxylic acid include terephthalic acid, isophthalic acid, naphthalene-1,4- or -2,6-dicarboxylic acid, 5-sodium sulfoisophthalic acid, and the like. Examples of ester derivatives include derivatives such as dialkyl esters and diaryl esters. Examples of the aliphatic dicarboxylic acid include dimer acid, glutaric acid, adipic acid, sebacic acid, azelaic acid, oxalic acid, and succinic acid. Among the dicarboxylic acid components, isophthalic acid components, naphthalene-1,4- or -2,6-dicarboxylic acid components are useful components for amorphizing the film, and increase the heat shrinkability of the film. Can do.
[0054]
In addition to the dicarboxylic acids, oxycarboxylic acids such as p-oxybenzoic acid; trivalent or higher carboxylic acids such as trimellitic anhydride and pyromellitic anhydride may be used in combination as necessary.
[0055]
The ratio of the second dicarboxylic acid component is, for example, about 3 to 80 mol%, preferably about 5 to 75 mol%, and more preferably about 10 to 70 mol% in 100 mol% of the dicarboxylic acid component.
[0056]
The polyhydric alcohol component (first polyhydric alcohol component, second polyhydric alcohol component) may be a diol component or a trihydric or higher alcohol component. Diols forming the diol component include ethylene glycol, propylene glycol, 1,4-butanediol, neopentyl glycol, 2,2-diethyl-1,3-propanediol, 1,6-hexanediol, 3-methyl- Alkylene glycols such as 1,5-pentanediol, 2-methyl-1,5-pentanediol, 1,9-nonanediol, 1,10-decanediol; cyclic alcohols such as 1,4-cyclohexanedimethanol; diethylene glycol; Ether glycols such as triethylene glycol, polyethylene glycol, polypropylene glycol, polyoxytetramethylene glycol, alkylene oxide adducts of bisphenol compounds or derivatives thereof; and dimer diols. Trivalent or higher alcohols include trimethylolpropane, glycerin, pentaerythritol and the like. Among the polyhydric alcohol components, a 1,4-cyclohexanedimethanol component, a neopentyl glycol component, and the like are useful components for amorphizing the film, and can improve the heat shrinkability of the film. Moreover, a 1, 4- butanediol component, a propylene glycol component, etc. are components useful for lowering the glass transition temperature of the film and enabling thermal shrinkage even at low temperatures.
[0057]
The ratio of the second alcohol component is, for example, about 3 to 80 mol%, preferably about 5 to 75 mol%, more preferably about 10 to 70 mol% in 100 mol% of the polyhydric alcohol component.
[0058]
The polyester may be produced by ring-opening polymerization of lactones (such as ε-caprolactone).
[0059]
Preferred second dicarboxylic acid component and second alcohol component include amorphous components (isophthalic acid component, naphthalene-1,4- or -2,6-dicarboxylic acid component, 1,4-cyclohexanedimethanol component , Neopentyl glycol component, etc.). When at least one of these components is contained, an amorphous film can be obtained. When obtaining an amorphous film, the proportion of the amorphous dicarboxylic acid component is, for example, 15 mol% or more, preferably 18 mol% or more, more preferably 20 mol% or more in 100 mol% of the dicarboxylic acid component. The ratio of the amorphous polyhydric alcohol component is, for example, 15 mol% or more, preferably 18 mol% or more, more preferably 20 mol% or more in 100 mol% of the polyhydric alcohol component.
[0060]
<Lubricant (fine particles)>
The heat-shrinkable polyester film roll of the present invention contains a lubricant in order to control the three-dimensional surface roughness SRz and SΔa within a predetermined range.
[0061]
Examples of the lubricant include inorganic fine particles (inorganic lubricant), organic salt fine particles, and polymer fine particles. Inorganic particles include carbonates (such as alkaline earth metal carbonates such as calcium carbonate, magnesium carbonate, and barium carbonate), sulfates (such as alkaline earth metal salts such as barium sulfate), and phosphates (lithium phosphate). Alkali metal phosphates such as calcium phosphate, alkaline earth metal phosphates such as magnesium phosphate), oxide particles (aluminum oxide, silicon oxide, titanium oxide, zirconium oxide, etc.), kaolin, talc, fluoride Examples include lithium. Particularly preferred inorganic particles are silica particles. The silica particles are more preferably an aggregate formed by agglomerating primary particles. Silica particles have good handling properties and are useful for obtaining a film having excellent transparency.
[0062]
Organic salt particles include oxalates (such as alkaline earth metal salts such as calcium oxalate), terephthalates (such as alkaline earth metal salts such as calcium, magnesium, and barium salts, zinc salts, and manganese salts). Is mentioned.
[0063]
Examples of the polymer particles include homopolymers or copolymers of vinyl monomers such as divinylbenzene, styrene, (meth) acrylic acid, polytetrafluoroethylene, benzoguanamine resin, thermosetting urea resin, thermosetting phenol resin, and the like. It is done. Preferred polymer particles are crosslinked polymer particles.
[0064]
The particle size and content of the lubricant are not particularly limited as long as the three-dimensional surface roughness SRz and / or SΔa can be controlled within a predetermined range, and are selected from the following ranges, for example.
[0065]
Particle size: For example, 0.01 μm or more (preferably 0.05 μm or more, more preferably 1 μm or more), 4 μm or less (preferably 3.5 μm or less, more preferably 3 μm or less)
If the particle size of the lubricant is too small, the three-dimensional surface roughness SRz and / or SΔa may be too small. If the particle size of the lubricant is too large, the three-dimensional surface roughness SRz and / or SΔa may become too large.
[0066]
Content: For example, 0.02 mass% or more (preferably 0.03 mass% or more, more preferably 0.04 mass% or more), 0.5 mass% or less (preferably 0.4 mass% or less, more preferably Is 0.2% by mass or less)
If the content of the lubricant is too small, the three-dimensional surface roughness SRz may become too small. If the content of the lubricant is too large, the three-dimensional surface roughness SRz may become too large.
[0067]
[Production method]
In the present invention, a film roll may be produced from a single raw material chip. However, a plurality of raw material chips (raw material pellets) are mixed, extruded from an extruder to form a film, and then stretched to form a heat-shrinkable film. It is desirable to manufacture the film roll by manufacturing the film and winding the film. Mixing multiple types of raw material chips is not only because the physical properties of the film can be easily adjusted according to the label application by adjusting the mixing ratio of the chips. According to the present invention, although the thermal characteristics of the film and the content of the lubricant differ from chip to chip, the thermal characteristics of the film and the three-dimensional surface roughness SRz are not particularly stable. This is because the transition temperature, the crystallization temperature, the melting temperature, etc. (preferably the glass transition temperature) and the three-dimensional surface roughness SRz can be stabilized and are particularly useful.
[0068]
<Production method of raw material polyester chip>
The manufacturing method of the polyester chip is not particularly limited, and can be obtained by a known method (melt polymerization method, other polymerization method, etc.). Examples of the melt polymerization method include a method in which an oligomer obtained from a direct reaction between a dicarboxylic acid and a glycol is polycondensed (direct polymerization method), a dimethyl ester of dicarboxylic acid and a glycol are subjected to a transesterification reaction, and then the polymerization is performed. A condensation method (a transesterification method) or any other production method can be applied. In the polymerization, either a homopolyester or a copolyester may be produced. The degree of polymerization of the polyester is preferably about 0.5 to 1.3 dl / g in terms of intrinsic viscosity (intrinsic viscosity).
[0069]
As the polymerization catalyst, various conventional catalysts can be used. For example, titanium-based catalyst, antimony-based catalyst, germanium-based catalyst, tin-based catalyst, cobalt-based catalyst, manganese-based catalyst, etc., preferably titanium-based catalyst (titanium tetrabutoxide) Etc.), antimony catalysts (such as antimony trioxide), germanium catalysts (such as germanium dioxide), cobalt catalysts (such as cobalt acetate), and the like.
[0070]
In addition to the polymerization catalyst, the above-mentioned lubricant (fine particles) is added to the polyester in order to control the three-dimensional surface roughness SRz when the film roll is produced. The addition timing of the lubricant (fine particles) is not particularly limited, and may be added at an arbitrary stage of the polyester polymerization process, or may be added after re-melting the polyester after the production of the polyester. In the present invention, a film roll is usually produced by mixing a plurality of polyester chips, but it is not necessary to add a lubricant to all chips, and a lubricant is added to one chip. It is convenient to use the chip as a master batch.
[0071]
In addition to the polymerization catalyst and the lubricant, the polyester has phosphoric acids such as phosphoric acid and phosphoric acid ester derivatives (such as phosphoric acid triethyl ester), metal salts (magnesium acetate). Mg salt such as magnesium chloride; Ca salt such as calcium acetate and calcium chloride; Mn salt such as manganese acetate and manganese chloride; Zn salt such as zinc chloride and zinc acetate; Co salt such as cobalt chloride and cobalt acetate) May be added. The amount of phosphoric acid added is such that the concentration of phosphorus atoms in the polyester is 200 ppm (mass basis) or less, and the amount of metal salt added is such that the metal ion concentration in the polyester is 300 ppm (mass basis) or less. It is. If too much phosphoric acid or metal salt is added, not only the coloring of the polyester becomes remarkable, but also the heat resistance and hydrolysis resistance of the polyester decrease.
[0072]
When adding phosphoric acid and a metal salt, it adds so that the molar atomic ratio (P / M) of total P amount (P) and total metal ion amount (M) may be 0.4-1.0. Is desirable. When added in the above proportion, the heat resistance and hydrolysis resistance can be prevented from decreasing. In addition, when it deviates from the said ratio, a film may color or a coarse particle may mix in a film.
[0073]
The timing for adding the phosphoric acid and the metal salt is not particularly limited, but in general, the phosphoric acid is preferably added before the polycondensation reaction, and the metal salt is added at the time of raw material charging, that is, before transesterification or before esterification. It is preferable to add.
[0074]
Further, if necessary, an antioxidant, an ultraviolet absorber, an antistatic agent, a coloring agent, an antibacterial agent, and the like can be added.
[0075]
<Mixing / extrusion / film formation of raw material chips>
In the present invention, as described above, a plurality of types of raw material chips having different thermal characteristics (such as glass transition temperature) and lubricant content are usually mixed and extruded to form a film. For example, when manufacturing a polyester-type film, the polyester-type chip | tip from which a composition, a polymerization degree, etc. (especially composition) differ is often mixed. By mixing chips having different compositions, the composition in the film can be easily adjusted, and the crystallinity and thermal characteristics of the film can be controlled. Moreover, if the chip | tip (masterbatch) containing a lubricating material is used and it mixes with the chip | tip which does not contain a lubricating material, a lubricating material content can be controlled easily.
[0076]
When mixing a polyester chip, a plurality of types of homopolyester chips may be mixed, a plurality of types of copolyester chips may be mixed, or a homopolyester chip and a copolyester chip may be mixed. . As the homopolyester chip and the copolyester chip, various chips that can adjust the dicarboxylic acid component and the polyhydric alcohol component in the film to the above-described composition can be used. Preferred homopolyester chips include polyethylene terephthalate chips, polybutylene chips Examples include terephthalate chips, polycyclohexylenedimethylene terephthalate chips, and polyethylene naphthalate chips. In preferred copolyester chips, the dicarboxylic acid component is a terephthalic acid component, the polyhydric alcohol component is an ethylene glycol component and an amorphous polyhydric alcohol component (1,4-cyclohexanedimethanol component, neopentyl glycol component, etc. The dicarboxylic acid component is a terephthalic acid component and a naphthalene-1,4- or -2,6-dicarboxylic acid component, and the polyhydric alcohol component is an ethylene glycol component, a dimer diol component, and a polytetramethylene glycol component. A chip having a molecular weight of about 500 to 800, preferably about 600 to 700, particularly about 650, is included.
[0077]
As described above, when mixing and extruding a plurality of types of raw material chips, mixing and extruding according to a normal method stabilizes the thermal characteristics and the lubricant content of the film (that is, the three-dimensional surface roughness SRz of the film). Since it is difficult, in the present invention, the thermal characteristics of the film and the three-dimensional surface roughness SRz are stabilized by mixing and extruding by a specific method.
[0078]
That is, when a plurality of types of raw material chips are mixed and extruded by a normal method, specifically, the procedure shown in the following (1) or (2) is often adopted. (1) A method of supplying a plurality of types of raw material chips to a mixing hopper continuously or intermittently, and finally supplying to a hopper (final hopper) immediately before or immediately above an extruder via a buffer hopper as necessary. (2) A method in which each raw material chip is mixed in the final hopper, and the mixed chip is quantitatively supplied to the extruder in accordance with the extrusion amount of the extruder to form a film.
[0079]
However, the material segregation (material uneven distribution) phenomenon that the composition of the mixed chips supplied from the final hopper to the extruder differs depending on whether the remaining amount of chips in the final hopper is large or small. The present inventors have found out. This phenomenon is likely to occur when the capacity and shape of the final hopper are inappropriate, particularly when the shape and specific gravity of each raw material chip are different from each other. As a result, the thermal characteristics in the film flow direction and the three-dimensional surface roughness SRz may vary greatly.
[0080]
As a method of obtaining a film having uniform thermal characteristics, a method of suppressing raw material segregation (raw material uneven distribution) in the final hopper, for example, (1) a method of matching the shape of each raw material chip, (2) fine powder form (3) a method for optimizing the shape of the final hopper, (4) a method for optimizing the capacity of the final hopper, and the like.
[0081]
(1) Method of matching the shape of each raw material chip
When the shapes of the raw material chips are matched, the raw material segregation can be reduced. In other words, if there is a difference in the size of the chips, when the mixed chips fall in the final hopper, small chips tend to fall first, so if the remaining amount of chips in the final hopper decreases, the ratio of large chips The segregation of raw materials appears. On the other hand, when the shape of each raw material chip is matched, it is possible to prevent a small chip from falling first, and to reduce raw material segregation.
[0082]
For example, a polyester chip is usually formed in a molten state after polymerization in the form of a strand from a polymerization apparatus, immediately cooled with water, and then cut with a strand cutter. For this reason, a polyester-type chip | tip normally becomes an elliptical column shape whose cross section is an ellipse. Therefore, when matching the shape of each polyester chip, it is desirable to match the average major axis (mm), average minor axis (mm), and average chip length (mm) of the cross-sectional ellipse of each polyester chip.
[0083]
Preferably, as the other raw material chips to be mixed with the raw material chip having the largest use amount (most chips), the average major axis (mm) and average minor axis (mm) of the cross-sectional ellipse and the average chip length (mm) are the largest. A chip having a range within ± 20% of each of the chips, preferably a chip having a range within ± 15%, is used.
[0084]
(2) Method for reducing fine powdery raw material chips
The fine powder (fine powdery raw material chip) generated by scraping of the raw material chip to be used promotes the occurrence of raw material segregation. Therefore, the raw material segregation can also be suppressed by reducing the ratio of the fine powder.
[0085]
The ratio of the fine powder in the raw material chips is preferably controlled within 1% by mass and more preferably within 0.5% by mass throughout the entire process until the raw material chips enter the extruder.
[0086]
As a method of reducing the fine powder, for example, a method of removing the fine powder generated in the process can be employed. For example, fine powder can be removed using a sieve or a cyclone air filter.
[0087]
(3) Method for optimizing the shape of the final hopper
For example, a funnel-shaped hopper is used as the final hopper, and the hypotenuse (side wall) is brought close to the vertical. If the hypotenuse (side wall) is brought closer to the vertical, a large chip can be easily dropped like a small chip, and the upper end of the content descends while maintaining a horizontal plane, which is effective in reducing raw material segregation. is there.
[0088]
The inclination angle of the hypotenuse (side wall) is, for example, 65 ° or more, preferably 70 ° or more. Note that the inclination angle of the hypotenuse (side wall) is an angle between the funnel-like hypotenuse (side wall) and a horizontal line segment.
[0089]
When a plurality of hoppers (such as hoppers for supplying each chip) are used upstream of the final hopper, the inclination angle of these hoppers is also preferably 65 ° or more, and preferably 70 ° or more.
[0090]
(4) Method for optimizing the capacity of the final hopper
When the mixed chips mixed in the final hopper are discharged from the final hopper to the extruder over time, segregation (uneven distribution) of the mixed chips may occur during feeding.
[0091]
Therefore, if the existence time of the mixed chips in the hopper is shortened, that is, if the capacity of the hopper is reduced to such an extent that the mixed chips can be discharged in a relatively short time, the material segregation can be suppressed.
[0092]
The appropriate capacity of the hopper is, for example, within a range of 5 to 120% by mass of (the discharge amount per hour of the extruder), preferably 10 to 100% by mass of the (discharge amount per hour of the extruder). Within the range of.
[0093]
Any one or a plurality of methods (1) to (4) for reducing the raw material segregation may be employed. Preferably, the method (1) (a method for matching the shapes of the respective raw material chips). ) And the remaining methods (2) to (4) are adopted as necessary.
[0094]
As a mixing procedure of a plurality of types of raw material chips, any of the above conventional procedures may be adopted, but while quantitatively supplying each raw material chip to the extruder continuously with a hopper (final hopper) directly above the extruder, The method of mixing each raw material chip is most preferable. In addition, a material whose chip size is controlled within the aforementioned range may be mixed in advance, and then supplied to the final hopper and the extruder via some intermediate (buffer) hoppers. When mixing multiple types of raw material chips, a method of mixing while quantitatively supplying multiple types of raw material chips into a hopper from a continuous supply type quantitative supply device, a method of mixing in advance using a blender, etc. In the latter case, it is preferable to pay attention to the raw material chip size and the like so that the raw material segregation does not occur when the mixture is discharged.
[0095]
The raw material chips are preferably dried at an appropriate stage before extrusion. For example, the raw material chips may be dried using a dryer (a hopper dryer, a paddle dryer, a vacuum dryer, etc.), and pressed into a film at an appropriate temperature (eg, about 200 to 300 ° C.) using an extruder, Undried raw material chips may be extruded into a film at an appropriate temperature (for example, about 200 to 300 ° C.) while removing moisture in a vented extruder.
[0096]
For extrusion, various existing methods such as a T-die method and a tubular method can be employed. After extrusion, it is desirable to obtain an unstretched film by quenching with a cooling roll such as a casting roll.
[0097]
<Extension>
In the present invention, the unstretched film is stretched at an appropriate magnification according to the type of film, so that the heat shrinkage rate of the film is in the predetermined range, that is, the heat shrinkage rate in the maximum shrinkage direction is 20% or more. It is controlled to become.
[0098]
The timing of the stretching treatment is not particularly limited. For example, after cooling by the cooling roll (such as a casting roll), the film may be wound into a roll once, and the film may be drawn from the roll and stretched. You may extend | stretch continuously, without winding up in roll shape.
[0099]
The stretching direction (maximum shrinkage direction of the film) may be the transverse (width) direction of the film or the longitudinal direction (flow direction) of the film, but the stretching direction is the transverse (width) direction of the film. Since it is practical in terms of production efficiency, the following description will be made taking as an example a stretching method in which the stretching direction (maximum shrinkage direction) is the transverse direction. When the stretching direction (the maximum shrinkage direction of the film) is the film longitudinal (longitudinal) direction, the stretching may be performed according to a normal operation such as changing the stretching direction in the following method by 90 °.
[0100]
When extending | stretching to a horizontal direction, it can extend | stretch using conventional extending | stretching means, such as a tenter.
[0101]
The stretching ratio in the maximum shrinking direction (in this example, the transverse direction) is not particularly limited as long as the thermal shrinkage rate can be 20% or more and the three-dimensional surface roughness SRz can be controlled within a predetermined range. However, if the draw ratio is not appropriate, the formation of protrusions by the lubricant may be insufficient. For example, it is about 2.3 to 7.3 times, more preferably 2.5 to 6 times. About 0 times. The stretching temperature can be set according to a normal method.
[0102]
The stretching is not limited to uniaxial stretching that extends only in the maximum shrinking direction (in this example, the transverse direction), but in a direction different from the maximum shrinking direction (for example, the orthogonal direction; in this example, the longitudinal direction of the film). Alternatively, biaxial stretching may be performed. The draw ratio in the different direction (in this example, the longitudinal direction) may be equal to or less than the draw ratio in the maximum shrinkage direction (lateral direction), for example, about 1 to 4 times, preferably 1.1 times to It is about twice. The biaxial stretching timing is not particularly limited, and for example, either sequential biaxial stretching or simultaneous biaxial stretching may be used, and restretching may be performed as necessary. In addition, when performing sequential biaxial stretching, the stretching order is not particularly limited, and stretching may be performed in any order such as vertical and horizontal, horizontal and vertical, vertical and horizontal, and horizontal and vertical.
[0103]
After the stretching treatment, heat treatment is performed at a predetermined temperature in the range of 60 ° C. to 110 ° C. while stretching 0-15% or relaxing 0-15%, and if necessary, in the range of 40 ° C. to 100 ° C. It is desirable to perform a further heat treatment at a predetermined temperature.
[0104]
Prior to the stretching treatment, the film may be preheated. In the preheating, for example, the film is heated to a temperature of about glass transition temperature (Tg) + 0 ° C. to Tg + 60 ° C.
[0105]
In performing the stretching, it is desirable to make various measures for making the film thickness uniform. If the film thickness is made uniform, meandering during film running can be suppressed, so that the workability of the film can be improved. Further, it is possible to prevent partial printing from being lost during film printing.
[0106]
As means for making the film thickness uniform, for example, (1) control of stretching temperature, (2) suppression of internal heat generation accompanying stretching, (3) control of preheating (preheating) conditions, (4) during stretching Examples include soaking the film surface temperature.
[0107]
(1) Control of stretching temperature
When controlling the stretching temperature, the stretching temperature is controlled so as not to become too high. If the stretching temperature is too high, the film thickness distribution value may become too large. If the stretching temperature is too high, the strength of the label may be insufficient when the label obtained from the heat-shrinkable film is quickly attached to the container.
[0108]
The stretching temperature is desirably controlled to, for example, glass transition temperature (Tg) + 40 ° C. or lower (preferably Tg + 15 ° C. or lower).
[0109]
Although the relation with the uniformity of thickness is small, the stretching temperature is desirably glass transition temperature (Tg) -20 ° C. or higher (preferably Tg-5 ° C. or higher). If the stretching temperature is too low, the thermal shrinkage rate of the film may be insufficient, and further the transparency of the film may be reduced.
[0110]
(2) Suppression of internal heat generation due to stretching
When the internal heat generation of the film accompanying stretching is suppressed, film temperature spots in the stretching direction (such as the width direction) can be reduced, and the uniformity of the thickness of the film (heat-shrinkable film) after stretching can be increased.
[0111]
In order to suppress the internal heat generation, it is desirable that the film is easily heated by appropriately controlling the heating conditions (for example, by increasing the supply speed of hot air). When there is an insufficiently heated portion, internal heat generation due to stretching orientation occurs. On the other hand, when the film is sufficiently heated, the molecular chain becomes slippery during stretching, so that internal heat generation hardly occurs.
[0112]
The heating condition is expressed as a heat transfer coefficient, for example, 0.0038 J / cm. ² ・ Sec ・ ℃ (0.0009 calories / cm ² · Sec · ° C) or more, preferably 0.0054 to 0.0084 J / cm ² ・ Sec ・ ℃ (0.0013 ～ 0.0020calories / cm ² ・ Sec · ° C.
[0113]
(3) Control of preheating (preheating) conditions
When preheating conditions are controlled, it is desirable to control the film so that it is gradually heated. When the film is gradually heated in the preheating step, the temperature distribution of the film can be made substantially uniform, so that the uniformity of the thickness of the stretched film (heat-shrinkable film) can be enhanced.
[0114]
The heating condition is expressed by a heat transfer coefficient, for example, 0.00544 J / cm. ² ・ Sec ・ ℃ (0.0013 calories / cm ² · Sec · ° C) or less. Moreover, in preheating, it is preferable to heat until a film surface temperature becomes the temperature in the range of Tg + 0 degreeC-Tg + 60 degreeC, and it is preferable that the temperature of a hot air is about Tg + 10 degreeC-Tg + 90 degreeC.
[0115]
Examples of the method for achieving the heat transfer coefficient include a method of slowing the hot air supply rate.
[0116]
(4) Soaking the film surface temperature during stretching
If the fluctuation range of the surface temperature of the film is reduced (soaking) when the film is stretched, the film can be stretched or heat-treated at the same temperature over the entire length of the film. Therefore, the thickness uniformity can be increased, and the heat shrinkage behavior of the film can be made uniform.
[0117]
The fluctuation range of the surface temperature is preferably such that the temperature at each point when the surface temperature of the film is measured at an arbitrary point is, for example, within the average temperature ± 1 ° C. of the film, and the average temperature ± 0.5 It is more preferable that the temperature is within a temperature.
[0118]
When stretching a film, since the film is stretched through various processes such as a preheating process before stretching, a stretching process, a heat treatment process after stretching, a relaxation process, and a re-stretching process, some of these processes are performed. Alternatively, it is preferable to use equipment that can reduce (homogenize) the fluctuation range of the surface temperature of the film in total. In particular, in order to make the thickness uniform over the entire length of the film, equipment that can reduce the fluctuation range of the surface temperature of the film in the preheating step and the stretching step (and in the heat treatment step after stretching if necessary). It is preferable to use it. In order to make the thermal shrinkage rate uniform, it is preferable to use equipment that can reduce the fluctuation range of the surface temperature of the film in the stretching step.
[0119]
Examples of the equipment that can reduce the fluctuation of the film surface temperature include, for example, equipment equipped with a wind speed control means (such as an inverter) for controlling the supply speed of hot air for heating the film, and stably heating the air. Heating means for preparing the hot air [500 kPa or less (5 kgf / cm ² And the like), and the like.
[0120]
Although the thickness of the heat-shrinkable film obtained by extending | stretching is not specifically limited, For example, when using for a label use, it is about 10-200 micrometers, Preferably it is about 20-100 micrometers.
[0121]
And the heat-shrinkable film roll of this invention can be manufactured by winding the said heat-shrinkable film on a winding core (core). The film wound around the film roll is preferably 200 mm or more in width and 300 m or more in length. The reason why the width is 200 mm or more is to increase the industrial utility value of the film roll. The length of 300 m or more is because the longer the film is wound, the more easily the thermal characteristics (such as glass transition temperature) fluctuate in the film flow direction. The effectiveness of the present invention that suppresses fluctuations in characteristics can be increased.
[0122]
The width of the heat-shrinkable film wound around the roll is preferably 300 mm or more, more preferably 400 mm or more. Moreover, the length of the heat-shrinkable film wound around the roll is preferably 400 m or more, more preferably 500 m or more.
[0123]
The upper limit of the width of the film is not particularly limited, but is generally 1500 mm or less because of ease of handling. The upper limit of the length of the film is not particularly limited, but may be determined depending on the film thickness from the viewpoint of ease of handling. For example, when the film thickness is 45 μm, the film length is preferably 6000 m or less.
[0124]
As the winding core, a plastic core or a metal core can be usually used. The diameter of these cores is, for example, about 2 to 10 inches (for example, 3 inches, 6 inches, and 8 inches).
[0125]
Since the heat-shrinkable film roll of the present invention obtained as described above has suppressed segregation of raw materials, the thermal properties (glass transition temperature, crystallization temperature, melting temperature, etc., particularly in the glass flow direction) Transition temperature) and three-dimensional surface roughness SRz are stable.
[0126]
Such a film roll can be widely used for applications such as shrink wrapping, shrink labels, cap seals, etc., but the film roll of the present invention is cut when producing a heat-shrinkable label by cutting it into a tube. In addition, the full label for covering the entire side of the container is manufactured and heat-shrinked into the container, and this full-labeled container is also excellent in blocking resistance when packed at a high temperature. It is particularly useful for use on labels (preferably full labels).
[0127]
【Example】
EXAMPLES Hereinafter, the present invention will be described more specifically with reference to examples. However, the present invention is not limited by the following examples, but may be appropriately modified within a range that can meet the purpose described above and below. Of course, it is possible to implement them, and they are all included in the technical scope of the present invention. In addition, the composition of the chip | tip and film roll used by an Example, a comparative example, and a reference example, and the measuring method of a physical property are as follows.
[0128]
(1) Confirmation of steady region and setting of sample cutout part
About the film roll on which the film of 1000 m in length obtained in Examples, Comparative Examples, and Reference Examples which will be described later is wound, a 5-point sample is cut out at 20 m intervals from the second end of the film (winding end), Five samples were cut out at intervals of 20 m from the inner part of the film from the first end part (winding start part) of the film toward the first end part, and the maximum heat shrinkage stress values in the maximum shrinkage direction of these samples were measured. (See below). The maximum heat shrinkage stress value of each sample was within a range of 3 MPa. Moreover, the production / stretching process was stable during the production of the film. Therefore, it was confirmed that each film roll corresponds to the steady region over the entire length of the film.
[0129]
In such a film roll, a sample was cut out from the steady region, and the following physical properties were measured. That is, the following physical properties: (3) “Solvent adhesive strength”, (6) “Shrinking finish”, (10) “Cutability”, (11) to (13) “Blocking”, (14) “Runability and abrasion resistance” In the measurement other than the “characteristic”, the first sample cutout portion is the second end portion of the film (0 m from the end of winding), and the final sample cutout portion is the first end portion of the film (0 m from the start of winding), Samples were taken from a total of 11 sample cutouts. Then, 10 samples were cut out from each sample cut-out portion, and the average value of the physical properties of the 10 samples in each sample cut-out portion was taken as the physical property value of the sample in the cut-out portion [Note (3) “Solvent adhesive strength” , (6) “Shrinkable finish”, (10) “Cutability”, (11) to (13) “Blocking”, (14) “Runability and abrasion resistance” I will elaborate on that.]
[0130]
(2) Component composition
Each sample (chip or film) is dissolved in a solvent prepared by mixing chloroform D (manufactured by Yurisop) and trifluoroacetic acid D1 (manufactured by Yurisop) at a ratio of 10: 1 (volume ratio) to prepare a sample solution, and NMR (“GEMINI-200”; manufactured by Varian) was used to measure the proton NMR of the sample solution under the measurement conditions of a temperature of 23 ° C. and a total number of 64 times. Based on the peak intensity of protons measured by NMR measurement, the composition ratio of monomers constituting the sample was calculated. In NMR measurement, the peak intensity of a predetermined proton was calculated, and the amount of ethylene glycol, neopentyl glycol, or 1,4-butanediol in 100 mol% of the polyhydric alcohol component was measured. In the following examples and comparative examples, the most alcohol component was ethylene glycol. Among the components other than ethylene glycol, the fluctuation (average value) of the content ratio of the most alcohol component (most secondary alcohol component) and the second most alcohol component (second secondary alcohol component) Maximum value and minimum value) were examined.
[0131]
(3) Solvent bond strength
A film roll (length: 1000 m) was slit to a width of 273 mm over the entire length, wound again into a roll, and stored for 250 hours in an environment controlled at a temperature of 30 ± 1 ° C. and a relative humidity of 85 ± 2%. . Subsequently, after printing three colors with grass-colored, gold-colored, and white-colored inks manufactured by Toyo Ink Manufacturing Co., Ltd., use a tube forming device so that it does not adhere to one end of the two slit ends of the film. 1,3-dioxolane on one side with a width of 2 ± 1 mm (application amount: 3.0 ± 0.3 g / mm) ² ), The film was immediately folded and the ends of both slits were superposed and bonded, and processed into a tube (processing speed: 80 mm / min). The tube was rolled up in a flat crushed state.
[0132]
Samples are cut from the tube roll at intervals of about 100 m. The first sample cutout portion is the end of winding of the tube (0 m from the end of winding). In addition, the final cut-out portion was a tube winding start portion (0 m from the winding start), and a total of 11 samples were collected. The tube-shaped sample obtained from each sample cut-out part was cut open so that the adhesion location was in the center, and a film-shaped sample was obtained. From this film-like sample, a film-like test piece (n = 10) having a length of 100 mm and a width of 15 mm was cut out, and this film-like test piece was set to a tensile tester (made by Baldwin, " STM-T ") is set so that the solvent adhesion part is located at the center of the chucks, a tensile test is performed at a temperature of 23 ° C and a tensile speed of 200 mm / min, and the peel strength of the adhesion part is measured. This is the solvent adhesive strength. In addition, 10 samples were cut out from each sample cutout part, and the average value of the solvent adhesive strength of 10 samples in each sample cutout part was taken as the solvent adhesive strength of the sample in the cutout part.
[0133]
Variations (average value, maximum value, minimum value) between the samples of the solvent adhesive strength were examined.
[0134]
(4) Thermal properties (glass transition temperature, crystallization temperature, melting temperature)
Using a DSC apparatus (model: DSC220) manufactured by Seiko Denshi Kogyo Co., Ltd., the thermal characteristics (glass transition temperature, crystallization temperature, melting temperature) of all samples were measured according to the above-described method.
[0135]
The variation (average value, maximum value, minimum value) between samples of the thermal characteristics was examined.
[0136]
(5) Thermal contraction rate in the maximum contraction direction
The film was cut into a 10 cm × 10 cm square along the longitudinal direction and the orthogonal direction thereof, immersed in warm water at 85 ° C. ± 0.5 ° C. for 10 seconds under no load, and immediately heat-shrinked. After immersing in water at +/− 0.5 ° C. for 10 seconds, the lengths of the sample in the vertical and horizontal directions were measured and determined according to the following formula.
Heat shrinkage rate (%) = 100 × (length before shrinkage−length after shrinkage) ÷ (length before shrinkage)
The direction with the largest shrinkage rate was defined as the maximum shrinkage direction.
[0137]
The variation (average value, maximum value, minimum value) between samples of the heat shrinkage rate in the maximum shrinkage direction was examined.
[0138]
(6) Shrinkage finish during full label formation
The sampling tube roll used in the above (3) “solvent adhesive strength” measurement is reused. That is, the tube roll is cut at a sampling portion formed at a distance of about 100 m on a tube roll having a length of 1000 m, 10 tubes having a length of 100 m are created, and the sampling portions remaining at both ends of the 100 m tube are cut off to obtain 100 m. The tube was trimmed. By cutting 7 out of 10 100 m tubes at an interval of 16 cm, a heat-shrinkable label for full label was created. The following shrinkage finishing test was performed on the total amount of the heat-shrinkable full label obtained. That is, a heat-shrinkable film label is attached to a glass bottle with a capacity of 300 ml, and a steam tunnel (model: SH-1500-L) manufactured by Fuji Astec Co., Ltd. is passed through the tunnel for 10 seconds, one zone temperature / 2. The glass bottle was passed under the condition of zone temperature = 80 ° C./90° C., and the entire side surface of the glass bottle and a part of the stopper were covered with the heat-shrinkable full label.
[0139]
The presence or absence of defects (wrinkles, label edge folding, color spots, insufficient shrinkage) was judged visually, and the shrinkage finish was evaluated in five stages. Standards are 5: Best finish, 4: Good finish, 3: Slight defects (within 2 locations), 2: Failures (3-5 locations), 1: Many failures (6 locations or more), 4 The above was passed and 3 or less was made unsuccessful. And the defect rate was computed based on the following formula.
[0140]
Defective rate = (number of rejected labels) ÷ (number of all labels) x 100 (%)
(7) Maximum heat shrinkage stress value
Prepare a sample with a length of 200 mm in the maximum shrinkage direction and a width of 20 mm, and heat the inside of the heating furnace of a tensile tester equipped with a hot air heating furnace (“Tensilon” manufactured by Toyo Seiki) to 90 ° C. Stop and place the sample in the furnace. The distance between chucks is 100 mm (constant). The door of the heating furnace is quickly closed, air blowing (90 ° C., blowing speed 5 m / s) is resumed, and heat shrinkage stress is detected and measured. The maximum value was read from the chart, and this was taken as the maximum heat shrinkage stress value (MPa).
[0141]
The variation (average value, maximum value, minimum value) between the samples of the maximum heat shrinkage stress value was examined.
[0142]
(8) Thermal contraction rate in the direction orthogonal to the maximum shrinkage direction
In the measurement of the heat shrinkage rate in the maximum shrinkage direction of (5), the heat shrinkage rate was also obtained in the direction orthogonal to the maximum shrinkage direction.
[0143]
The variation (average value, maximum value, minimum value) between samples of the heat shrinkage rate in the orthogonal direction was examined.
[0144]
(9) Three-dimensional surface roughness SΔa, SRz
The surface of the sampled sample was stylused (measured length: 1 mm, cutoff value: 0.25 mm) along the longitudinal direction of the film roll. The stylus used a stylus type three-dimensional roughness meter (ET-30K, manufactured by Kosaka Manufacturing Co., Ltd.) (needle radius 2 μm, load 30 mg). The uneven profile having a length of 1 mm obtained by the stylus was divided into 500 points at 2 μ pitch, and the height of each store was taken into a three-dimensional roughness analyzer (AT-30K, manufactured by Kosaka Manufacturing Co., Ltd.).
[0145]
The same operation as described above was continuously performed 150 times (that is, over 0.3 mm in the width direction of the film) at intervals of 2 μm in the width direction of the film roll. Then, the three-dimensional surface roughness SΔa and SRz were obtained by causing the analyzer to calculate.
[0146]
Variations (maximum value, minimum value) between the samples of the three-dimensional surface roughness SΔa and SRz were examined.
[0147]
(10) Cutting ability (Defect rate)
One of the 10 100 m tubes prepared at the time of (6) “shrinkage finishing” evaluation was cut to evaluate the cutting property (defective rate). More specifically, while feeding the tube at a speed of 10 m / min, a portion of the tube that was not printed was continuously cut with a cutting machine (cutting interval = about 8 cm) to produce an 8 cm label. The cutting part was opened by hand, and the cutting property was evaluated in three stages. Criteria: ○: Can be opened without resistance, Δ: Resistance when opening, ×: High resistance when opening or impossible to open, and ○ was accepted. And the defect rate was computed based on the following formula.
[0148]
Defective rate = (number of rejected labels) ÷ (number of all labels) x 100 (%)
(11) Full label blocking rate during hot warm storage
The fully labeled glass bottle obtained in the above (6) “shrinkage finish” test is used. Immediately after the shrinkage finish test, the surface of the fully labeled glass bottle is at a high temperature. Then, about half of the full-label glass bottles immediately after the test were sequentially boxed in a cardboard box (3 × 4 = 12 pieces) so that the labels were in contact with each other. This cardboard box was stored in a room controlled at a temperature of 50 ± 1 ° C. for 24 hours and then taken out, and the degree of blocking between labels was evaluated in three stages. The criteria were: ○: no blocking, Δ: blocking, but no trace left when peeled, x: blocking present, and peeling mark remained, and ○ and Δ passed. And the blocking incidence was computed based on the following formula.
[0149]
Blocking rate = (number of failed labels) / (number of all labels) x 100 (%)
(12) Full label blocking rate during storage at room temperature
The same as the “blocking occurrence rate during hot worm” in (11) above, except that about half of the remaining full-label glass bottles were used and the storage temperature was about 20 ° C.
[0150]
(13) Partial label blocking rate during hot warm storage
A heat-shrinkable label for a partial label was prepared by cutting two of the 10 100 m tubes produced at the time of the evaluation of (6) “shrinkage finish” at an interval of 8 cm. Using this heat-shrinkable partial label, a partially labeled glass bottle was produced in the same manner as in the evaluation of (6) “Shrinkable finish”. This partially labeled glass bottle was treated in the same manner as in (11) “Full label blocking rate during hot warm storage” to examine the blocking rate at the time of partial labeling.
[0151]
(14) Film runnability and abrasion resistance
Separately from the above (3) “Solvent adhesive strength”, the film was slit to a width of 100 mm over the entire length to form a tape. After winding this tape into a roll, the tape was pulled out from this roll, spread over metal guide rolls arranged at intervals of 0.2 m, and then connected to a roll for winding. All the tapes were run at a speed of 100 m / min. The amount of scratches on the surface of the tape after running and the amount of white powder generated on the surface of the guide roll were visually observed and evaluated according to the following criteria.
[0152]
(A) Driving performance
First grade: There are many scratches
Level 2: Many scratches
Level 3: Scratches
Grade 4: Almost no scratches
Grade 5: No scratches
(B) Scratch resistance
First grade: Very much white powder is generated
Second grade: A lot of white powder is generated
Grade 3: Some white powder is generated
Grade 4: Almost no white powder is generated
Grade 5: No white powder generated
Synthesis Example 1 (Synthesis of polyester chip)
In a stainless steel autoclave equipped with a stirrer, a thermometer and a partial reflux condenser, dimethyl terephthalate (DMT) as a dicarboxylic acid ester, ethylene glycol (EG) and neopentyl glycol (NPG) as a polyhydric alcohol [ EG / NPG = 70/30 (molar ratio)] was charged so that the polyhydric alcohol was 2.2 times the molar ratio of DMT, and 0.05 mol% of zinc acetate as a transesterification catalyst (based on the acid component) And 0.025 mol% of antimony trioxide as a polycondensation catalyst (based on the acid component) was added, and a transesterification reaction was carried out while distilling off the produced methanol out of the system. Thereafter, polycondensation was performed under reduced pressure conditions of a temperature of 280 ° C. and a pressure of 26.7 Pa (0.2 Torr). The obtained copolymer polyester was taken out from the polymerization apparatus in the form of a strand, immediately cooled with water, and then cut with a strand cutter. The intrinsic viscosity of the obtained polyester chip (Chip A) is 0.70 dl / g, the average length of the chip is 4.0 mm, the average major axis of the chip cross section is 3.6 mm, and the average minor axis is 2.8 mm. Met.
[0153]
Synthesis Examples 2-4
Chips B to G shown in Table 1 were obtained in the same manner as in Synthesis Example 1. In the table, DMT represents a terephthalic acid component, EG represents an ethylene glycol component, BD represents a butanediol component, NPG represents a neopentyl glycol component, and DEG represents a diethylene glycol component.
[0154]
Further, an inorganic lubricant having various particle diameters (particle diameter: 0.007 to 5.8 μm, silica particles) was added to the chip C to prepare a master batch (inorganic lubricant content: 0.7 mass%). . A plurality of types of the master batch were prepared in terms of the particle size of the inorganic lubricant, and since all of them have the same resin component and shape as the chip C, they are collectively referred to as a chip C ′. In the following examples, comparative examples, and reference examples, the amount and particle size of the inorganic lubricant in the film roll were prepared by adjusting the amount of the master batch (chip C ′).
[0155]
The characteristics of each chip are summarized in Table 1 below.
[0156]
[Table 1]

[0157]
In Table 1, the intrinsic viscosity was determined as follows. In other words, the intrinsic viscosity was originally measured by weighing 0.1 g of a chip, dissolving in 25 ml of a mixed solvent of phenol / tetrachloroethane = 3/2 (mass ratio), and then measuring at 30 ± 0.1 ° C. with an Ostwald viscometer. did. The intrinsic viscosity [η] is obtained by the following formula (Huggins formula).
[0158]
[Expression 2]

[0159]
Where η _sp : Specific viscosity, t ₀ : Falling time of solvent using Ostwald viscometer, t: Falling time of tip solution using Ostwald viscometer, C: Concentration of tip solution. In the actual measurement, the intrinsic viscosity was calculated by the following approximate equation where k = 0.375 in the Huggins equation.
[0160]
[Equation 3]

[0161]
Where η _r : Relative viscosity.
[0162]
Example 1
Each chip obtained in the above synthesis example was separately pre-dried. Chip A, chip C, chip C ′ and chip D were continuously fed separately to the hopper directly above the single screw extruder using a quantitative screw feeder, and each chip was mixed in this hopper (chip A: 66 mass%, the sum of chips C and C ′: 9 mass%, chip D: 25 mass%). This mixed chip was melt-extruded at a temperature of 280 ° C. using an extruder and quenched with a casting roll to obtain an unstretched film having a thickness of 180 μm. The hopper has a capacity of about 150 kg of chips, and the discharge rate of the extruder is 450 kg per hour. The inclination angle of the hopper side wall is 70 °.
[0163]
The unstretched film was continuously stretched over 1000 m. In the stretching, after preheating for 10 seconds at a temperature of 100 ° C., the film was stretched 4.0 times in the transverse direction at a temperature of 80 ° C. using a tenter, and subsequently heat-treated at a temperature of 80 ° C. for 10 seconds. A shrinkable polyester film was obtained. The fluctuation range of the film surface temperature when the heat-shrinkable film is produced continuously for 1000 m is the average temperature ± 0.7 ° C. in the preheating step, the average temperature ± 0.5 ° C. in the stretching step, and the average temperature ± 0.5 in the heat treatment step. It was within the range of ° C. The surface temperature of the film was measured using an infrared non-contact surface thermometer (the same applies to the following examples and comparative examples).
The obtained film was slit into a width of 500 mm and a length of 1000 m, and wound on a 3-inch paper tube to obtain a heat-shrinkable film roll.
[0164]
Comparative Example 1
Three hoppers having a capacity of about 400 kg of chips and a side wall inclination angle of 60 ° are installed in series. In the first hopper, 65% by mass of chip B and 10% by mass of chips C and C ′ in total. , And after mixing D25% by mass of the chip D, the mixed chip is supplied to the hopper directly above the single-screw extruder via the second hopper and the third hopper. Similarly, a heat-shrinkable polyester film having a thickness of 45 μm was produced, and a heat-shrinkable film roll was produced in the same manner as in Example 1.
[0165]
Example 2
Each chip obtained in the above synthesis example was separately pre-dried. Chip A, chip C, chip C ′, and chip D were mixed in the hopper while supplying them separately to the hopper directly above the single-screw extruder using a quantitative screw feeder (chip A: 51 mass). %, Total of chips C and C ′: 23 mass%, chip D: 26 mass%). This mixed chip was melt-extruded at a temperature of 280 ° C. using an extruder and quenched with a casting roll to obtain an unstretched film having a thickness of 180 μm. The hopper has a capacity of about 100 kg of chips, and the discharge rate of the extruder is 450 kg per hour. The inclination angle of the hopper side wall is 75 °.
[0166]
The unstretched film was continuously stretched over 1000 m. In stretching, after preheating for 10 seconds at a temperature of 105 ° C., the film is stretched 4.0 times in the transverse direction at a temperature of 75 ° C. using a tenter, followed by heat treatment at a temperature of 75 ° C. for 10 seconds. A shrinkable polyester film was obtained. The fluctuation range of the film surface temperature when the heat-shrinkable film is continuously produced 1000 m is as follows: the average temperature ± 0.6 ° C. in the preheating process, the average temperature ± 0.5 ° C. in the stretching process, and the average temperature ± 0.7 in the heat treatment process. It was within the range of ° C. The obtained film was slit into a width of 500 mm and a length of 1000 m, and wound on a 3-inch paper tube to obtain a heat-shrinkable film roll.
[0167]
Comparative Example 2
Three hoppers having a capacity of about 400 kg of chips and a side wall tilt angle of 60 ° are installed in series. In the first hopper, chip B51 mass%, chips C and C ′ total 23 mass% And Comparative Example 1 except that the mixed chip is supplied to the hopper directly above the single-screw extruder via the second hopper and the third hopper after mixing 26 mass% of the chip D. Similarly, a heat-shrinkable polyester film having a thickness of 45 μm was produced, and a heat-shrinkable film roll was produced in the same manner as in Comparative Example 1.
[0168]
Reference example 1
Each chip obtained in the above synthesis example was separately pre-dried. Chip E, chip F, and chip G were mixed in the hopper while supplying them separately to the hopper directly above the single screw extruder using a quantitative screw feeder (chip E: 60% by mass, chip). F: 25% by mass, chip G: 15% by mass). This mixed chip was melt-extruded at a temperature of 280 ° C. using an extruder and quenched with a casting roll to obtain an unstretched film having a thickness of 180 μm. The hopper has a capacity of about 100 kg of chips, and the discharge rate of the extruder is 450 kg per hour. The inclination angle of the hopper side wall is 75 °.
[0169]
The unstretched film was continuously stretched over 1000 m. In stretching, after preheating at a temperature of 105 ° C. for 10 seconds, using a tenter, the film is stretched 4.0 times in the transverse direction at a temperature of 78 ° C., and subsequently heat-treated at a temperature of 80 ° C. for 10 seconds to obtain a heat of 45 μm in thickness. A shrinkable polyester film was obtained. The fluctuation range of the film surface temperature when the heat-shrinkable film is continuously produced by 1000 m is as follows: average temperature ± 0.5 ° C. in the preheating step, average temperature ± 0.4 ° C. in the stretching step, and average temperature ± 0.5 in the heat treatment step. It was within the range of ° C. The obtained film was slit into a width of 500 mm and a length of 1000 m, and wound on a 3-inch paper tube to obtain a heat-shrinkable film roll.
[0170]
Tables 2 to 13 below show chip compounding ratios in the above Examples, Comparative Examples, and Reference Examples, and physical properties of the heat-shrinkable film rolls obtained in Examples, Comparative Examples, and Reference Examples.
[0171]
[Table 2]

[0172]
[Table 3]

[0173]
[Table 4]

[0174]
[Table 5]

[0175]
[Table 6]

[0176]
[Table 7]

[0177]
[Table 8]

[0178]
[Table 9]

[0179]
[Table 10]

[0180]
[Table 11]

[0181]
[Table 12]

[0182]
[Table 13]

[0183]
As is clear from Table 9, the film rolls of Examples 1-2, Comparative Examples 1-2, and Reference Example 1 all have a heat shrinkage of 20% or more in the maximum shrinkage direction and have heat shrinkability. It can be said that.
[0184]
Here, the film rolls of Examples 1 and 2 and Reference Example 1 are clear from Table 6 because the shapes of the blended chips are uniform as is clear from Table 2 as compared with the film rolls of Comparative Examples 1 and 2. Thus, the glass transition temperature is stable in the longitudinal direction of the film. Therefore, it has excellent cutting properties (see Table 13). In addition, the film rolls of Examples 1 and 2 and Reference Example 1 have stable thermal shrinkage rates in the maximum shrinkage direction (see Table 9). Therefore, it also has excellent shrinkage finish (see Table 13). Further, the film rolls of Examples 1 and 2 and Reference Example 1 are the content of the most secondary alcohol component, the content of the second secondary alcohol component, the solvent adhesive strength, the crystallization temperature, the melting temperature, and the maximum heat shrinkage. It is also stable in terms of stress and thermal shrinkage in the orthogonal direction (see Tables 3-5, 7-8, 10).
[0185]
However, the film roll of Reference Example 1 has a three-dimensional surface roughness SRz that is too small (see Table 12) and has poor blocking resistance during hot worm storage when used as a full label (see Table 13). The roughness SΔa is too small (see Table 12), and the running property (scratch resistance) is poor. In addition, the film roll of Comparative Example 1 also has a three-dimensional surface roughness SRz and SΔa that are too small, and has poor blocking resistance and running property (scratch resistance) during hot worm storage when used as a full label. Has a non-uniform crystallization temperature and melting temperature (see Tables 7 to 8), and thus has poor blocking resistance during hot worm storage (see Table 13), and the three-dimensional surface roughness SRz is too large. (See Table 12), poor wear resistance (see Table 13). On the other hand, since the film rolls of Examples 1 and 2 contain an appropriate amount of inorganic lubricant (see Table 2), the three-dimensional surface roughness SΔa and SRz are controlled within an appropriate range ( (See Table 12). Therefore, the entire side surface of the container is coated as a label (full label) and is excellent in blocking resistance even when stored in a hot worm, and further excellent in running property and abrasion resistance of the film (see Table 13). Even when the film roll of Reference Example 1 is used as a partial label or stored at room temperature, there is no problem in blocking resistance after bottle coating.
[0186]
【The invention's effect】
According to the present invention, even in a heat-shrinkable film roll manufactured from a plurality of types of chips, the glass transition temperature in the film flow direction and the three-dimensional surface roughness SRz are controlled within a predetermined range. In addition, it can prevent thermal fusion and cutting performance degradation when cutting tubes processed from film, and further, the full label cut from the tube is in close contact with the container by heat shrinkage, and the resulting product is packed at a high temperature. Sometimes blocking of full labels can be prevented. For this reason, the yield of a film roll can be improved.

Claims (8)

A film roll formed by winding a heat-shrinkable polyester film having a length of 1000 to 6000 m ,
This heat-shrinkable film roll has an ethylene terephthalate unit as a base unit and is further selected from (a) an isophthalic acid component and a naphthalene-1,4- or -2,6-dicarboxylic acid component. The second dicarboxylic acid component and / or (b) one or more second selected from 1,4-cyclohexanedimethanol component, neopentyl glycol component, 1,4-butanediol component, and propylene glycol component Containing the diol component of
Moreover, the heat-shrinkable polyester film roll has a first end portion on the winding start side and a second end portion on the winding end in the steady region where the film physical properties are stable in the length direction of the film. The first sample cutout portion is provided within 2 m inside the second end portion, and the final cutout portion is provided within 2 m inside the first end portion. A heat-shrinkable polyester film roll characterized by satisfying the following requirements (1), (2), and (3) when a sample cutout portion is provided every about 100 m.
(1) About each sample of 10 cm x 10 cm square shape cut out from each sample cut-out part, each sample was dipped in hot water at 85 ° C for 10 seconds and then dipped in water at 25 ° C for 10 seconds and pulled up. (2) When the glass transition temperature of each sample cut out from each of the sample cutout portions is measured, the glass transition temperature of each sample is It is within ± 4 ° C. of the average value of the glass transition temperature of the sample. (3) When the three-dimensional surface roughness SRz is measured for the sample cut out from each sample cut-out part, the three-dimensional surface roughness SRz of all the samples is Within the range of 0.6 to 1.5 μm Furthermore, the following requirements (4) are satisfied, The heat-shrinkable polyester film roll of Claim 1 characterized by the above-mentioned.
(4) When the three-dimensional surface roughness SΔa is measured for the samples cut out from the respective sample cutout portions, the three-dimensional surface roughness SΔa of all the samples is in the range of 0.008 to 0.04.   The heat-shrinkable polyester according to claim 1 or 2, wherein the heat-shrinkable film contains a lubricant having an average particle diameter of 0.01 to 3 µm in a range of 0.02 to 0.5 mass%. Film roll.   The heat-shrinkable film is obtained by mixing a plurality of kinds of raw material chips having different glass transition temperatures, and then forming and stretching the film. Heat-shrinkable polyester film roll.   The heat-shrinkable polyester film roll according to any one of claims 1 to 4, wherein the film is substantially amorphous. The film constituting the film roll is a substantially crystalline film having a crystallization temperature of 100 ° C or higher, and further satisfies the following requirement (5). A heat-shrinkable polyester film roll according to claim 1.
(5) When the crystallization temperature is measured for the sample cut out from each cutout part, the crystallization temperature of each sample is within ± 5 ° C. of the average value of the crystallization temperatures of all the samples. The film constituting the film roll is a substantially crystalline film having a melting temperature of 180 to 230 ° C, and further satisfies the following requirement (6). The heat-shrinkable polyester film roll according to any one of the above.
(6) When the melting temperature is measured for the sample cut out from each cutout part, the melting temperature of each sample is within ± 5 ° C. of the average value of the melting temperatures of all the samples. Heat shrinkable film roll according to claim 1 in which the wound film on the width 200mm or more.