JPH0427016B2 - - Google Patents
Info
- Publication number
- JPH0427016B2 JPH0427016B2 JP58168969A JP16896983A JPH0427016B2 JP H0427016 B2 JPH0427016 B2 JP H0427016B2 JP 58168969 A JP58168969 A JP 58168969A JP 16896983 A JP16896983 A JP 16896983A JP H0427016 B2 JPH0427016 B2 JP H0427016B2
- Authority
- JP
- Japan
- Prior art keywords
- stretching
- film
- temperature
- stage
- longitudinal
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Expired - Lifetime
Links
- 229920000728 polyester Polymers 0.000 claims description 13
- 238000004519 manufacturing process Methods 0.000 claims description 10
- 229920006267 polyester film Polymers 0.000 claims description 9
- 238000000034 method Methods 0.000 description 13
- 238000002474 experimental method Methods 0.000 description 6
- 239000002245 particle Substances 0.000 description 5
- 239000002994 raw material Substances 0.000 description 5
- ADCOVFLJGNWWNZ-UHFFFAOYSA-N antimony trioxide Chemical compound O=[Sb]O[Sb]=O ADCOVFLJGNWWNZ-UHFFFAOYSA-N 0.000 description 4
- 230000015572 biosynthetic process Effects 0.000 description 4
- 238000002425 crystallisation Methods 0.000 description 4
- 230000008025 crystallization Effects 0.000 description 4
- LYCAIKOWRPUZTN-UHFFFAOYSA-N Ethylene glycol Chemical compound OCCO LYCAIKOWRPUZTN-UHFFFAOYSA-N 0.000 description 3
- OKKJLVBELUTLKV-UHFFFAOYSA-N Methanol Chemical compound OC OKKJLVBELUTLKV-UHFFFAOYSA-N 0.000 description 3
- 238000009998 heat setting Methods 0.000 description 3
- QPFMBZIOSGYJDE-UHFFFAOYSA-N 1,1,2,2-tetrachloroethane Chemical compound ClC(Cl)C(Cl)Cl QPFMBZIOSGYJDE-UHFFFAOYSA-N 0.000 description 2
- NBIIXXVUZAFLBC-UHFFFAOYSA-N Phosphoric acid Chemical compound OP(O)(O)=O NBIIXXVUZAFLBC-UHFFFAOYSA-N 0.000 description 2
- VYPSYNLAJGMNEJ-UHFFFAOYSA-N Silicium dioxide Chemical compound O=[Si]=O VYPSYNLAJGMNEJ-UHFFFAOYSA-N 0.000 description 2
- GWEVSGVZZGPLCZ-UHFFFAOYSA-N Titan oxide Chemical compound O=[Ti]=O GWEVSGVZZGPLCZ-UHFFFAOYSA-N 0.000 description 2
- 230000007423 decrease Effects 0.000 description 2
- WOZVHXUHUFLZGK-UHFFFAOYSA-N dimethyl terephthalate Chemical compound COC(=O)C1=CC=C(C(=O)OC)C=C1 WOZVHXUHUFLZGK-UHFFFAOYSA-N 0.000 description 2
- 238000010438 heat treatment Methods 0.000 description 2
- 229910052751 metal Inorganic materials 0.000 description 2
- 239000002184 metal Substances 0.000 description 2
- 230000005855 radiation Effects 0.000 description 2
- 230000003746 surface roughness Effects 0.000 description 2
- 238000005809 transesterification reaction Methods 0.000 description 2
- MMINFSMURORWKH-UHFFFAOYSA-N 3,6-dioxabicyclo[6.2.2]dodeca-1(10),8,11-triene-2,7-dione Chemical group O=C1OCCOC(=O)C2=CC=C1C=C2 MMINFSMURORWKH-UHFFFAOYSA-N 0.000 description 1
- 239000005995 Aluminium silicate Substances 0.000 description 1
- 229920002799 BoPET Polymers 0.000 description 1
- OYPRJOBELJOOCE-UHFFFAOYSA-N Calcium Chemical compound [Ca] OYPRJOBELJOOCE-UHFFFAOYSA-N 0.000 description 1
- 241001391944 Commicarpus scandens Species 0.000 description 1
- 229920001634 Copolyester Polymers 0.000 description 1
- WHXSMMKQMYFTQS-UHFFFAOYSA-N Lithium Chemical compound [Li] WHXSMMKQMYFTQS-UHFFFAOYSA-N 0.000 description 1
- ISWSIDIOOBJBQZ-UHFFFAOYSA-N Phenol Chemical compound OC1=CC=CC=C1 ISWSIDIOOBJBQZ-UHFFFAOYSA-N 0.000 description 1
- OAICVXFJPJFONN-UHFFFAOYSA-N Phosphorus Chemical compound [P] OAICVXFJPJFONN-UHFFFAOYSA-N 0.000 description 1
- 241001422033 Thestylus Species 0.000 description 1
- 238000005299 abrasion Methods 0.000 description 1
- 239000000654 additive Substances 0.000 description 1
- 230000001070 adhesive effect Effects 0.000 description 1
- 229910000147 aluminium phosphate Inorganic materials 0.000 description 1
- 235000012211 aluminium silicate Nutrition 0.000 description 1
- 229910052791 calcium Inorganic materials 0.000 description 1
- 239000011575 calcium Substances 0.000 description 1
- XQKKWWCELHKGKB-UHFFFAOYSA-L calcium acetate monohydrate Chemical compound O.[Ca+2].CC([O-])=O.CC([O-])=O XQKKWWCELHKGKB-UHFFFAOYSA-L 0.000 description 1
- 229940067460 calcium acetate monohydrate Drugs 0.000 description 1
- 239000003054 catalyst Substances 0.000 description 1
- 238000006243 chemical reaction Methods 0.000 description 1
- 239000007795 chemical reaction product Substances 0.000 description 1
- 238000007796 conventional method Methods 0.000 description 1
- 230000006866 deterioration Effects 0.000 description 1
- 238000010586 diagram Methods 0.000 description 1
- BXKDSDJJOVIHMX-UHFFFAOYSA-N edrophonium chloride Chemical compound [Cl-].CC[N+](C)(C)C1=CC=CC(O)=C1 BXKDSDJJOVIHMX-UHFFFAOYSA-N 0.000 description 1
- 238000005516 engineering process Methods 0.000 description 1
- 150000002148 esters Chemical class 0.000 description 1
- 238000009499 grossing Methods 0.000 description 1
- NLYAJNPCOHFWQQ-UHFFFAOYSA-N kaolin Chemical compound O.O.O=[Al]O[Si](=O)O[Si](=O)O[Al]=O NLYAJNPCOHFWQQ-UHFFFAOYSA-N 0.000 description 1
- 229910052744 lithium Inorganic materials 0.000 description 1
- IAQLJCYTGRMXMA-UHFFFAOYSA-M lithium;acetate;dihydrate Chemical compound [Li+].O.O.CC([O-])=O IAQLJCYTGRMXMA-UHFFFAOYSA-M 0.000 description 1
- 239000000314 lubricant Substances 0.000 description 1
- 239000000463 material Substances 0.000 description 1
- 239000011259 mixed solution Substances 0.000 description 1
- 238000002156 mixing Methods 0.000 description 1
- 230000002093 peripheral effect Effects 0.000 description 1
- 229910052698 phosphorus Inorganic materials 0.000 description 1
- 239000011574 phosphorus Substances 0.000 description 1
- 238000006068 polycondensation reaction Methods 0.000 description 1
- -1 polyethylene terephthalate Polymers 0.000 description 1
- 229920000139 polyethylene terephthalate Polymers 0.000 description 1
- 239000005020 polyethylene terephthalate Substances 0.000 description 1
- 229920000642 polymer Polymers 0.000 description 1
- 238000006116 polymerization reaction Methods 0.000 description 1
- 238000003825 pressing Methods 0.000 description 1
- 238000007788 roughening Methods 0.000 description 1
- 239000000377 silicon dioxide Substances 0.000 description 1
- 239000003381 stabilizer Substances 0.000 description 1
- 239000000126 substance Substances 0.000 description 1
- ISIJQEHRDSCQIU-UHFFFAOYSA-N tert-butyl 2,7-diazaspiro[4.5]decane-7-carboxylate Chemical compound C1N(C(=O)OC(C)(C)C)CCCC11CNCC1 ISIJQEHRDSCQIU-UHFFFAOYSA-N 0.000 description 1
- 239000004408 titanium dioxide Substances 0.000 description 1
- DQWPFSLDHJDLRL-UHFFFAOYSA-N triethyl phosphate Chemical compound CCOP(=O)(OCC)OCC DQWPFSLDHJDLRL-UHFFFAOYSA-N 0.000 description 1
- 238000007740 vapor deposition Methods 0.000 description 1
- 238000004804 winding Methods 0.000 description 1
Landscapes
- Shaping By String And By Release Of Stress In Plastics And The Like (AREA)
Description
本発明は、二軸延伸ポリエステルフイルムの製
造方法に関し、更に詳しくは平坦易滑性に優れた
二軸配向ポリエチレンテレフタレートフイルムの
高速製膜法に関するものである。
ポリエステル二軸延伸フイルムは、優れた機械
的性質、熱的性質、電気的性質、耐薬品性を有す
るため各種用途に多用されているが、とりわけ磁
気テープ用ベースフイルムとして非常に有用なフ
イルムである。この磁気テープ用ベースフイルム
の品質は、磁気テープの品質に強く影響するの
で、磁気テープの技術進歩に伴つてベースフイル
ムの高品質化への要求も高度化している。
例えば、ビデオ用磁気テープを例とすると、そ
の出力、各種Ｓ／Ｎ比、ドロツプアウト、エンベ
ローブなどの特性はベースフイルムの平坦性と関
連しているし、テープの巻姿、走行性、耐摩耗性
等は、ベースフイルムの滑り性と密接に関連して
いる。従つて磁気テープ、とりわけビデオ用磁気
テープには表面の平坦性と易滑性を併せ持つポリ
エステルフイルムが要望されている。特に、記録
密度を高めるため磁性層の厚さを小さくしたり、
金属蒸着法を採用する際にはベースフイルムの平
坦、易滑性はより切実な課題である。
ポリエステルフイルムの易滑化は、周知の方法
で微小な外部添加粒子または内部析出粒子を付与
し、フイルム表面を粗面化することにより達成さ
れたが、このような方法では通常行なわれている
ポリエステルフイルムの製造条件を採る限り、フ
イルムの平坦化に限界があつて高級磁気テープ用
には不向きであつた。本発明者らは、特開昭58−
160123号公報において、特定の延伸条件を規定す
ることにより、平坦易滑性、磁性層との接着性に
優れ、厚さむらの少ないポリエステルフイルムの
製造方法を提案した。
つまり、ポリエステル未延伸フイルムを多段階
で縦方向に延伸するに際し、先ず、△ｎ（複屈析
率）が0.025〜0.055となるよう延伸し、次いで、
95〜150℃の温度で△ｎが0.080を越えないよう延
伸して得られた縦方向延伸フイルムを横方向に延
伸する製造方法である。しかるに該製造方法にお
いては、縦延伸倍率を高くすることができず、フ
イルムの生産性の点で問題があつた。
本発明者らは、このような欠点を解消すべく鋭
意検討の結果、前段延伸を通常採用されている延
伸温度より高温度でしかも高倍率で延伸すること
により、平坦易滑性、厚みむらを悪化させること
なく、縦延伸倍率が通常の延伸法と比べても極め
て高く高速製膜可能な延伸法を見出したものであ
る。
すなわち本発明の要旨は、ポリエステルフイル
ム未延伸フイルムを100℃より高く130℃以下の温
度（T1）で少くとも１段階縦方向に延伸して△
ｎを0.025〜0.055とし（以下“前段縦延伸”と称
することがある。）、次いで同一方向にT1〜150℃
の温度範囲で△ｎが0.080を越えないように延伸
した（以下“後段縦延伸”と称することがある。）
後、横方向に延伸することを特徴とする二軸延伸
ポリエステルフイルムの製造方法である。ここで
△ｎ（複屈折率）は、Ｒ／ｄ（Ｒ：リターデーシヨ
ン、ｄ：フイルム厚み）で示される（特開昭54−
8672号公報参照）。
本発明に用いるポリエステルとは、エチレンテ
レフタレート単位を、80重量％以上含むポリエス
テルであつて、残りの20重量％以下は、共重合ポ
リエステルまたは他のポリマーであつてもよい。
該ポリエステル中には例えばリン酸、亜リン酸及
びそれらのエステル等の安定剤や二酸化チタン、
微粒子状シリカ、カオリン等の添加剤、滑剤など
が含まれていてもよい。
本発明においては、ポリエステル未延伸フイル
ムを先ず△ｎが0.025〜0.055となるように縦方向
に１段階または多段階で延伸し、少くとも１段階
は100℃より高く130℃以下で延伸する。△ｎが
0.025より小さいと後段縦延伸後の厚さむらが大
きくなる。また、△ｎが0.025より小さいと、延
伸倍率を高くすることができず生産性が低下す
る。すなわち、延伸倍率を高くして△ｎを0.025
以下にしようとすると、延伸温度が高くなりすぎ
結晶化が進行して横延伸が困難となり、破断が多
発する。一方、△ｎが0.055より大きいと、後段
縦延伸を終えたフイルムの縦方向厚さむらが大き
くなり、不適である。△ｎの好ましい範囲は
0.030〜0.050である。
△ｎを0.025〜0.055の範囲とする前段縦延伸工
程における延伸は１〜３段階で行うのが好まし
い。ここで縦延伸倍率の向上を計るためには前段
縦延伸倍率は好ましくは2.5倍以上さらに好まし
くは3.2倍以上である。一方前段の延伸により結
晶化が進行しすぎると次工程で破断し易くなるの
で前段縦延伸倍率は5.0倍以下であることが好ま
しい。このように縦延伸倍率の向上を計るべく前
段の延伸倍率を高めてかつその複屈折率が所定の
値をもつためには、少くとも１段階の延伸温度
（T1）は、100℃より高く130℃以下であり、好ま
しくは101℃〜125℃、さらに好ましくは101℃〜
120℃である。100℃以下では第１段延伸後の△ｎ
を0.025〜0.055の範囲にしようとすると十分に縦
延伸倍率を高くすることができない。これに対し
100℃を越える温度以上つまりスーパードロー延
伸開始温度近傍以上にして始めて、縦延伸倍率に
対する縦方向の屈折率の増加が急激に低下し、縦
延伸倍率向上に対する寄与が極めて大きくなる。
多段延伸の際には、途中配向緩和のための熱処理
工程を含めれば更に高倍率に延伸してもよい。配
向緩和のための熱処理は、延伸温度以上結晶化開
始温度以下で極く短時間行なえばよい。
これまで前段の延伸を上記のような高温で行わ
なかつた理由は高温で延伸すると厚さむらが悪化
すると考えられたためであるが、本発明者らは、
100℃より高い高温で延伸して△ｎを0.025〜
0.055としても、延伸倍率を高く設定することに
より同じ△ｎで比較した時低温で延伸したものと
比べて厚さむらが遜色ないことを見出し、本発明
に到達したものである。
かくして縦方向延伸工程の前段で先ず△ｎが
0.025〜0.055の縦延伸フイルムが得られる。次い
で後段ではT1〜150℃で△ｎが0.080を越えないよ
うに縦方向に延伸する。縦方向の後段延伸工程に
おける延伸温度が95℃より低いと△ｎが0.080以
下で二軸延伸フイルムの厚さむらが改良されない
し、150℃より高いと結晶化の進行が著しく横延
伸性を悪化させる。更に後段延伸においては、△
ｎが0.080を越えないように延伸することは、平
坦易滑化及び横延伸時の破断防止の為に必須であ
る。後段の延伸倍率は1.05〜1.7倍であり、好ま
しくは1.1〜1.6倍、さらに好ましくは1.1〜1.4倍
である。後段の延伸は、通常縦延伸工程の最終段
階として実施され１段階で短時間に行うことが好
ましい。
全体の縦延伸倍率は好ましくは3.0〜５倍、さ
らに好ましくは3.5〜5.0倍である。
このように縦方向に延伸したフイルムを横方向
延伸工程へ送り、80〜160℃で25〜45倍に横方向
に延伸した後、180〜250℃で熱固定し、二軸延伸
フイルムとする。
本発明によれば、厚さむらを増幅させることな
くしかも、平坦易滑性、接着性に優れた性質を維
持しながら、縦方向の延伸倍率が極めて高く高速
製膜によるコストダウンを計りうるフイルムが得
られるので、磁気テープ用とりわけ平坦易滑性が
強く要求されるビデオテープ用ベースフイルムを
安価に供給することが出来る。
以上、縦−横−熱固定のバランスフイルムにつ
いて述べたが、当然本発明はこれに限るものでは
ない。すなわち、縦−横延伸後再度好ましくは
1.1〜1.5倍、さらに好ましくは1.1〜1.4倍に縦方
向に延伸しセミテンシライズフイルム、テンシラ
イズフイルムとすることができる。また、この再
縦延伸の代わりに再横延伸したり、再縦延伸後さ
らに横延伸したり、続いて縦延伸すること等によ
り横セミテンシライズフイルム、横テンシライズ
フイルム、縦横テンシライズフイルムを製造する
のも好ましい。
以下、実施例によつて本発明を説明するが、フ
イルムの諸性質の測定方法は次の通りである。
(1) 厚さむら
安立電気社製連続フイルム厚さ測定器によ
り、二軸延伸フイルムの横方向中央部を縦方向
に沿つて測定し、次式により算出した。
厚さむら＝
フイルム最大厚さ−フイルム最小厚さ／フイルム平均厚
さ
×100（％）
(2) 摩擦係数（μ）
固定した硬質クロムメツキ金属ロール（直径
６mm）に、フイルムを巻き付角135゜（θ）で接
触させ、53ｇ（T2）の荷重を一端にかけて１
ｍ／minの速度でこれを走行させて他端の抵抗
力（T1（ｇ））を測定し、次式により走行中の
摩擦係数を求めた。
μ＝１／θln（T1／T2）
＝0.424ln（T1／53）
(3) 中心線平均表面粗さ（Ra）
小坂研究所社製表面粗さ測定器（SE−3FK）
によつて次のように求めた。触針の先端半径は
2μｍ、荷重は30mgである。フイルム断面曲線
からその中心線の方向に基準長さＬ（2.5mm）の
部分を抜き取り、この抜き取り部分の中心線を
Ｘ軸、縦倍率の方向をＹ軸として、粗さ曲線ｙ
＝ｆ（ｘ）で表わしたとき、次の式で与えられ
た値をμｍで表わす。但し、カツトオフ値は
80μｍである。Raは縦方向に５点、横方向に５
点の計10点の平均値を求めた。
１／Ｌ∫L 0｜ｆ（ｘ）｜dx
(4) 極限粘度（〔η〕）
試料200mgをフエノール／テトラクロロエタ
ン＝50／50の混合溶液20mlに加え、約110℃で
１時間加熱溶解後30℃で測定した。
(5) 複屈折率
カールツアイス社製偏光顕微鏡により、リタ
ーデーシヨンを測定し、次式により複屈折率
（△ｎ）を求めた。
△ｎ＝Ｒ／ｄ
但しＲ；リターデーシヨン
ｄ；フイルム厚さ
(6) フイルム温度
バーンズ社製赤外線放射温度計により延伸部
のフイルム温度を測定した。
(7) F5値
1/2インチ幅、チヤツク間50mm長の試料フイ
ルムを東洋ボールドウイン社製テンシロン
（UTM−）により、20℃、65％RHにて50
mm／minで引張り、５％伸張時の荷重を初期の
断面積で割り、Kg／mm2単位で表わした。
実施例 １
（ポリエステルの製造法）
ジメチルテレフタレート100部、エチレングリ
コール70部、酢酸カルシウム一水塩0.10部及び酢
酸リチウム二水塩0.17部を反応器に仕込み、加熱
昇温すると共にメタノールを留出させてエステル
交換反応を行ない、反応開始後約４時間を要して
230℃に達せしめ、実質的にエステル交換を終了
した。
次にこの反応生成物にトリエチルホスフエート
0.35部を添加し、更に重縮合触媒として三酸化ア
ンチモン0.05部を添加した後、常法に従つて重合
し、ポリエステルを得た。該ポリエステル中には
粒径およそ0.5〜1μ程度の均一で微細なカルシウ
ム、リチウム及びリン元素を含む析出粒子が多数
認められた。該ポリエステルＡは〔η〕＝0.65で
あつた。
別途このような内部析出粒子を殆んど含まない
ポリエステルＢ（〔η〕＝0.65）を製造し、先のポ
リエステルとＡ／Ｂ＝２／３（重量比）の割合で
混合し製膜用原料とした。
（製膜法）
ポリエチレンテレフタレート未延伸フイルム
は、第１図に示した縦方向延伸装置とテンター
（横方向延伸及び熱固定装置）を用いて二軸延伸
フイルムに製膜した。表１には実施例１および実
施例２で採用したロール表面温度条件とロール材
質を示した。以下に製膜法の詳細を述べる。先ず
原料ポリエステルを乾燥後、溶融押出し、厚さ
160〜200μの未延伸フイルム（〔η〕＝0.62）を得
た。次いで第１図に示した縦方向延伸装置にこれ
を通し、ロール１〜４でフイルムを85℃に予熱し
た後ロール５，５′と６の間でロール周速差によ
り表２に示すとおり2.8〜3.7倍に第１段延伸し、
引き続きロール９，９′と１０の間で、表２に示
すとおり1.1〜1.7倍に第２段延伸した。なおロー
ル９，９′と１０の間では、赤外線ヒーター１３
で加熱しており、赤外線ヒーターの反対面から赤
外放射温度計で第２段延伸部のフイルム温度を測
定したところ110℃であつた。かくして得られた
縦方向延伸フイルムを次にテンターで140℃で3.8
倍に横方向に延伸し、215℃で熱固定して厚さ
15μの二軸延伸フイルムを得た。縦延伸フイルム
の△ｎおよび得られた二軸延伸フイルム（実験番
号１〜５）の性質を表２に示した。また、実験番
号６として原料Ａと原料Ｂの混合重量比を１：１
とし、ロール表面温度を表１に示す条件とし、ま
た延伸倍率を表２に示す条件として同様に二軸延
伸フイルムを得た。結果を表２に示す。表２よ
り、本発明方法により明らかに総合延伸倍率が極
めて高くなることが分かる。更に平坦易滑性を維
持し、また厚さむらに優れたフイルムを得るに
は、第１段延伸後の△ｎが0.025〜0.055の間でな
ければならないことが理解される。
The present invention relates to a method for producing a biaxially oriented polyester film, and more particularly to a high-speed method for producing a biaxially oriented polyethylene terephthalate film having excellent flatness and slipperiness. Polyester biaxially stretched film has excellent mechanical properties, thermal properties, electrical properties, and chemical resistance, so it is widely used for various purposes, but it is especially useful as a base film for magnetic tapes. . The quality of the base film for magnetic tape has a strong influence on the quality of the magnetic tape, and as the technology of magnetic tapes advances, the demand for higher quality base films has also become more sophisticated. For example, in the case of a video magnetic tape, its characteristics such as output, various S/N ratios, dropout, and envelope are related to the flatness of the base film, and the tape's winding form, runnability, and abrasion resistance are related to the flatness of the base film. etc. are closely related to the slipperiness of the base film. Therefore, there is a demand for polyester films that have both surface flatness and slipperiness for magnetic tapes, especially video magnetic tapes. In particular, reducing the thickness of the magnetic layer to increase recording density,
When employing the metal vapor deposition method, the flatness and slipperiness of the base film are more pressing issues. Smoothness of polyester film was achieved by roughening the surface of the film by adding minute externally added particles or internally precipitated particles using a well-known method. As long as the manufacturing conditions for the film were taken, there was a limit to the flattening of the film, making it unsuitable for use in high-grade magnetic tapes. The inventors of the present invention have discovered that
In Japanese Patent No. 160123, a method for producing a polyester film with excellent flatness, easy slipping properties, adhesion to a magnetic layer, and little thickness unevenness was proposed by specifying specific stretching conditions. That is, when stretching an unstretched polyester film in the longitudinal direction in multiple stages, first, it is stretched so that Δn (birefringence) is 0.025 to 0.055, and then,
This is a manufacturing method in which a longitudinally stretched film obtained by stretching at a temperature of 95 to 150°C so that Δn does not exceed 0.080 is stretched in the transverse direction. However, in this manufacturing method, it was not possible to increase the longitudinal stretching ratio, and there was a problem in terms of film productivity. The inventors of the present invention have made extensive studies to solve these drawbacks, and have found that by performing the first-stage stretching at a higher temperature than the normally employed stretching temperature and at a higher magnification, smoothness and uneven thickness can be improved. We have discovered a stretching method that allows for high-speed film formation with an extremely high longitudinal stretching ratio compared to normal stretching methods without causing any deterioration. That is, the gist of the present invention is to stretch an unstretched polyester film in the longitudinal direction at least one step at a temperature (T 1 ) higher than 100°C and lower than 130°C.
n is 0.025 to 0.055 (hereinafter sometimes referred to as "pre-stage longitudinal stretching"), and then T 1 to 150°C in the same direction.
It was stretched so that Δn did not exceed 0.080 in the temperature range of (hereinafter sometimes referred to as "second stage longitudinal stretching").
This is a method for producing a biaxially stretched polyester film, which is characterized in that the film is then stretched in the transverse direction. Here, △n (birefringence) is expressed as R/d (R: retardation, d: film thickness) (Japanese Patent Application Laid-Open No. 54-1979-
(See Publication No. 8672). The polyester used in the present invention is a polyester containing 80% by weight or more of ethylene terephthalate units, and the remaining 20% by weight or less may be a copolyester or other polymer.
The polyester contains stabilizers such as phosphoric acid, phosphorous acid and their esters, titanium dioxide,
Additives such as particulate silica and kaolin, lubricants, and the like may be included. In the present invention, an unstretched polyester film is first stretched in the longitudinal direction in one step or in multiple steps so that Δn is 0.025 to 0.055, and at least one step is stretched at a temperature higher than 100°C and below 130°C. △n is
When it is smaller than 0.025, the thickness unevenness after longitudinal stretching becomes large. Moreover, if Δn is smaller than 0.025, the stretching ratio cannot be increased, resulting in a decrease in productivity. In other words, increase the stretching ratio and set △n to 0.025.
If an attempt is made to lower the stretching temperature below, the stretching temperature becomes too high and crystallization progresses, making transverse stretching difficult and causing frequent breaks. On the other hand, if Δn is larger than 0.055, the film after the post-stage longitudinal stretching will have large longitudinal thickness unevenness, which is unsuitable. The preferred range of △n is
It is 0.030-0.050. It is preferable that the stretching in the first stage longitudinal stretching step in which Δn is in the range of 0.025 to 0.055 be carried out in 1 to 3 stages. In order to improve the longitudinal stretching ratio, the first stage longitudinal stretching ratio is preferably 2.5 times or more, and more preferably 3.2 times or more. On the other hand, if crystallization progresses too much due to the stretching in the first stage, it becomes easy to break in the next step, so the longitudinal stretching ratio in the first stage is preferably 5.0 times or less. In this way, in order to increase the stretching ratio in the first stage in order to improve the longitudinal stretching ratio, and in order for the birefringence index to have a predetermined value, the stretching temperature (T 1 ) in at least one stage must be higher than 100°C. 130°C or less, preferably 101°C to 125°C, more preferably 101°C to
The temperature is 120℃. △n after the first stage stretching below 100℃
If you try to make it in the range of 0.025 to 0.055, you cannot make the longitudinal stretching ratio high enough. In contrast to this
When the temperature exceeds 100° C., that is, near the super draw stretching start temperature, the increase in the refractive index in the longitudinal direction with respect to the longitudinal stretching ratio rapidly decreases, and the contribution to increasing the longitudinal stretching ratio becomes extremely large.
In multi-stage stretching, if a heat treatment step for orientation relaxation is included in the middle, stretching may be performed to a higher magnification. The heat treatment for orientation relaxation may be performed for a very short time at a temperature higher than the stretching temperature and lower than the crystallization start temperature. The reason why the previous stage of stretching has not been carried out at the high temperatures mentioned above is because it was thought that stretching at high temperatures would worsen the thickness unevenness, but the present inventors
Stretch at a high temperature higher than 100℃ to increase △n from 0.025
Even when the stretching ratio is set to 0.055, the inventors have found that by setting the stretching ratio high, the thickness unevenness is comparable to that drawn at a low temperature when compared at the same Δn, and this is what led to the present invention. Thus, in the first stage of the longitudinal stretching process, △n is
A longitudinally stretched film of 0.025 to 0.055 is obtained. Then, in the latter stage, the film is stretched in the longitudinal direction at T 1 to 150° C. so that Δn does not exceed 0.080. If the stretching temperature in the later stretching process in the longitudinal direction is lower than 95°C, △n is 0.080 or less and the thickness unevenness of the biaxially stretched film cannot be improved, and if it is higher than 150°C, the progress of crystallization will significantly deteriorate the transverse stretchability. let Furthermore, in the latter stage stretching, △
Stretching so that n does not exceed 0.080 is essential for flattening and smoothing and preventing breakage during lateral stretching. The stretching ratio in the latter stage is 1.05 to 1.7 times, preferably 1.1 to 1.6 times, more preferably 1.1 to 1.4 times. The latter stage of stretching is usually carried out as the final stage of the longitudinal stretching process, and is preferably carried out in one stage in a short period of time. The overall longitudinal stretching ratio is preferably 3.0 to 5 times, more preferably 3.5 to 5.0 times. The film thus stretched in the longitudinal direction is sent to a transverse stretching step where it is stretched 25 to 45 times in the transverse direction at 80 to 160°C, and then heat set at 180 to 250°C to form a biaxially stretched film. According to the present invention, a film that does not amplify thickness unevenness, maintains excellent flatness, smoothness, and adhesive properties, has an extremely high stretching ratio in the longitudinal direction, and can reduce costs through high-speed film formation. As a result, base films for magnetic tapes, particularly video tapes which are strongly required to be flat and slippery, can be supplied at low cost. Although the vertical-horizontal-heat-set balance film has been described above, the present invention is not limited thereto. That is, preferably after longitudinal-lateral stretching,
A semi-tensilized film or a tensilized film can be obtained by stretching in the longitudinal direction 1.1 to 1.5 times, more preferably 1.1 to 1.4 times. In addition, transverse semi-tensilized films, transverse tensilized films, and longitudinal and transverse tensilized films can be produced by performing transverse stretching instead of this longitudinal re-stretching, or by further transverse stretching after longitudinal re-stretching, and then longitudinal stretching. It is also preferable to do so. The present invention will be explained below with reference to Examples, and the methods for measuring various properties of the film are as follows. (1) Thickness unevenness A biaxially stretched film was measured at the center in the horizontal direction along the longitudinal direction using a continuous film thickness measuring device manufactured by Anritsu Electric Co., Ltd., and was calculated using the following formula. Thickness unevenness =
Maximum film thickness - Minimum film thickness / Average film thickness × 100 (%) (2) Coefficient of friction (μ) The film was wound around a fixed hard chrome-plated metal roll (diameter 6 mm) at a wrapping angle of 135° (θ). contact and apply a load of 53g (T 2 ) to one end.
This was run at a speed of m/min, the resistance force (T 1 (g)) at the other end was measured, and the coefficient of friction during running was determined using the following equation. μ = 1/θln (T 1 / T 2 ) = 0.424ln (T 1 / 53) (3) Center line average surface roughness (Ra) Surface roughness measuring instrument manufactured by Kosaka Laboratory Co., Ltd. (SE-3FK)
It was calculated as follows. The tip radius of the stylus is
2μm, load is 30mg. A part of the standard length L (2.5 mm) is extracted from the film cross-sectional curve in the direction of its center line, and with the center line of this extracted part as the X axis and the vertical magnification direction as the Y axis, the roughness curve y is
=f(x), the value given by the following formula is expressed in μm. However, the cutoff value is
It is 80μm. Ra is 5 points vertically and 5 horizontally
The average value of a total of 10 points was calculated. 1/L∫ L 0 | f(x) | dx (4) Intrinsic viscosity ([η]) Add 200 mg of sample to 20 ml of a mixed solution of phenol/tetrachloroethane = 50/50, and heat and dissolve at approximately 110°C for 1 hour. Measured at 30°C. (5) Birefringence Retardation was measured using a polarizing microscope manufactured by Carl Zeiss, and the birefringence (△n) was determined using the following formula. Δn=R/d where R: Retardation d: Film thickness (6) Film temperature The temperature of the film at the stretched portion was measured using an infrared radiation thermometer manufactured by Burns. (7) F5 value A sample film with a width of 1/2 inch and a length of 50 mm between chucks was measured at 50°C at 20°C and 65% RH using a Tensilon (UTM-) manufactured by Toyo Baldwin.
The load at 5% elongation was divided by the initial cross-sectional area and expressed in kg/ mm2 . Example 1 (Production method of polyester) 100 parts of dimethyl terephthalate, 70 parts of ethylene glycol, 0.10 parts of calcium acetate monohydrate, and 0.17 parts of lithium acetate dihydrate were charged into a reactor, heated to raise the temperature, and distilled off methanol. The transesterification reaction takes about 4 hours after the start of the reaction.
The temperature was reached to 230°C, and the transesterification was substantially completed. This reaction product is then treated with triethyl phosphate.
After adding 0.35 part of antimony trioxide and further adding 0.05 part of antimony trioxide as a polycondensation catalyst, polymerization was carried out according to a conventional method to obtain a polyester. In the polyester, many uniform and fine precipitated particles containing calcium, lithium, and phosphorus elements with a particle size of approximately 0.5 to 1 μm were observed. The polyester A had [η]=0.65. Separately, polyester B ([η] = 0.65) containing almost no such internal precipitated particles is produced and mixed with the above polyester at a ratio of A/B = 2/3 (weight ratio) to form a raw material for film formation. And so. (Film Forming Method) The polyethylene terephthalate unstretched film was formed into a biaxially stretched film using a longitudinal stretching device and a tenter (transverse stretching and heat setting device) shown in FIG. Table 1 shows the roll surface temperature conditions and roll materials employed in Examples 1 and 2. The details of the film forming method are described below. First, the raw material polyester is dried, then melt extruded and the thickness
An unstretched film ([η]=0.62) of 160 to 200μ was obtained. Next, the film was passed through the longitudinal stretching apparatus shown in FIG. 1, and after preheating the film to 85°C with rolls 1 to 4, the film was stretched to 2.8°C by the difference in peripheral speed between rolls 5, 5' and 6 as shown in Table 2. 1st stage stretching to ~3.7 times,
Subsequently, the film was stretched in a second stage between rolls 9, 9' and 10 to a ratio of 1.1 to 1.7 times as shown in Table 2. Note that an infrared heater 13 is installed between the rolls 9, 9' and 10.
The temperature of the film in the second stage stretching section was measured at 110° C. using an infrared radiation thermometer from the opposite side of the infrared heater. The longitudinally stretched film thus obtained was then heated to 3.8°C at 140°C in a tenter.
Stretch it twice in the transverse direction and heat set it at 215℃ to achieve the desired thickness.
A 15μ biaxially stretched film was obtained. Table 2 shows the Δn of the longitudinally stretched film and the properties of the obtained biaxially stretched films (experiment numbers 1 to 5). In addition, as experiment number 6, the mixing weight ratio of raw material A and raw material B was 1:1.
A biaxially stretched film was similarly obtained under the conditions of the roll surface temperature shown in Table 1 and the stretching ratio shown in Table 2. The results are shown in Table 2. From Table 2, it can be seen that the method of the present invention clearly increases the overall stretching ratio. Furthermore, it is understood that in order to maintain flatness and smoothness and obtain a film with excellent thickness unevenness, Δn after the first stage stretching must be between 0.025 and 0.055.
【表】【table】
【表】【table】
【表】
実施例 ２
実施例１と同様のポリエステル原料を用いて、
第１図の縦方向延伸装置により、厚さ160〜210μ
の未延伸フイルムをロール５，５′と６の間で△
ｎが0.040となるよう３、４倍に第１段延伸した
のちロール９，９′と１０の間で△ｎが0.060とな
るよう表３に示すとおり1.2〜1.6倍に第２段延伸
した。各ロールの表面温度は表１の通りである。
赤外線ヒーター１３の容量調整により、ロール
９，９′と１０の間の第２段延伸部のフイルム温
度を表３に示すとおり93〜152℃に変化させて縦
方向延伸フイルムを得た。横延伸及び熱固定条件
は実施例１と同様である。得られた二軸延伸フイ
ルム（実験番号７〜10）の性質を表３に示した。[Table] Example 2 Using the same polyester raw material as in Example 1,
The thickness is 160 to 210 μ by the longitudinal stretching device shown in Figure 1.
The unstretched film is rolled between rolls 5, 5' and 6.
After the first stage stretching was carried out by 3 to 4 times so that n was 0.040, the second stage stretching was carried out between rolls 9, 9' and 10 by 1.2 to 1.6 times so that Δn was 0.060 as shown in Table 3. Table 1 shows the surface temperature of each roll.
By adjusting the capacity of the infrared heater 13, the temperature of the film in the second stage stretching section between rolls 9, 9' and 10 was varied from 93 to 152 DEG C. as shown in Table 3 to obtain a longitudinally stretched film. The lateral stretching and heat setting conditions were the same as in Example 1. Table 3 shows the properties of the obtained biaxially stretched films (experiment numbers 7 to 10).
【表】
以上の結果より第２段延伸温度は95℃以上150
℃以下でなければならないことが分かる。
実施例 ３
縦延伸工程及び次の横延伸工程までは実施例１
の実験番号４及び実験番号６と同じ延伸を行な
い、その後150℃で熱固定したのち再度縦方向に
130℃で1.3倍延伸し215℃で熱固定したフイルム
を得、それぞれ実験番号11、12とした。それぞれ
の二軸延伸後のフイルムの性質を表４に示した。[Table] From the above results, the second stage stretching temperature is 95℃ or higher and 150℃.
It is clear that the temperature must be below ℃. Example 3 Example 1 up to the longitudinal stretching process and the next horizontal stretching process
The same stretching as in Experiment No. 4 and Experiment No. 6 was carried out, and after heat setting at 150℃,
Films were stretched 1.3 times at 130°C and heat-set at 215°C, and were designated as experiment numbers 11 and 12, respectively. Table 4 shows the properties of each film after biaxial stretching.
【表】
表４より本発明は、テンシライズフイルムに対
しても平坦易滑性をそこなわず極めて高速製膜可
能な製造法であることは明らかである。[Table] From Table 4, it is clear that the present invention is a manufacturing method that enables extremely high-speed film formation without impairing the flatness and slipperiness of tensilized films.
第１図は実施例で用いた縦延伸装置の概略図で
ある。５，５′および９，９′は延伸ニツプロー
ル、６，１０は延伸ロール、１３は赤外線ヒータ
ーを示す。
FIG. 1 is a schematic diagram of a longitudinal stretching apparatus used in Examples. 5, 5' and 9, 9' are stretching nip rolls, 6, 10 are stretching rolls, and 13 is an infrared heater.
Claims (1)
高く130℃以下の温度T1で少くとも１段階縦方向
に延伸して△ｎを0.025〜0.055とし、次いで同一
方向にT1〜150℃の温度範囲で△ｎが0.080を越え
ないように延伸した後、横方向に延伸することを
特徴とする二軸延伸ポリエステルフイルムの製造
方法。1. A polyester unstretched film is stretched in the longitudinal direction at least one step at a temperature T 1 higher than 100°C and lower than 130°C to obtain △n of 0.025 to 0.055, and then stretched in the same direction at a temperature T 1 to 150°C. A method for producing a biaxially stretched polyester film, which comprises stretching in the transverse direction after stretching so that Δn does not exceed 0.080.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP16896983A JPS6061233A (en) | 1983-09-13 | 1983-09-13 | Manufacture of biaxially oriented polyester film |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP16896983A JPS6061233A (en) | 1983-09-13 | 1983-09-13 | Manufacture of biaxially oriented polyester film |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPS6061233A JPS6061233A (en) | 1985-04-09 |
| JPH0427016B2 true JPH0427016B2 (en) | 1992-05-08 |
Family
ID=15877921
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP16896983A Granted JPS6061233A (en) | 1983-09-13 | 1983-09-13 | Manufacture of biaxially oriented polyester film |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JPS6061233A (en) |
Families Citing this family (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP2611421B2 (en) * | 1989-03-30 | 1997-05-21 | ダイアホイルヘキスト株式会社 | Method for producing polyester film |
| JP2679234B2 (en) * | 1989-04-04 | 1997-11-19 | ダイアホイルヘキスト株式会社 | Method for producing polyester film |
Citations (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS5075A (en) * | 1973-04-28 | 1975-01-06 | ||
| JPS50136365A (en) * | 1974-04-17 | 1975-10-29 | ||
| JPS58118220A (en) * | 1982-01-06 | 1983-07-14 | Toray Ind Inc | Preparation of biaxial orientated polyethylen terephthalate film |
| JPS58140221A (en) * | 1982-02-17 | 1983-08-19 | Toray Ind Inc | Manufacture of polyethyleneterephtharate film |
-
1983
- 1983-09-13 JP JP16896983A patent/JPS6061233A/en active Granted
Patent Citations (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS5075A (en) * | 1973-04-28 | 1975-01-06 | ||
| JPS50136365A (en) * | 1974-04-17 | 1975-10-29 | ||
| JPS58118220A (en) * | 1982-01-06 | 1983-07-14 | Toray Ind Inc | Preparation of biaxial orientated polyethylen terephthalate film |
| JPS58140221A (en) * | 1982-02-17 | 1983-08-19 | Toray Ind Inc | Manufacture of polyethyleneterephtharate film |
Also Published As
| Publication number | Publication date |
|---|---|
| JPS6061233A (en) | 1985-04-09 |
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