JPH0445336B2 - - Google Patents
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- Publication number
- JPH0445336B2 JPH0445336B2 JP2976988A JP2976988A JPH0445336B2 JP H0445336 B2 JPH0445336 B2 JP H0445336B2 JP 2976988 A JP2976988 A JP 2976988A JP 2976988 A JP2976988 A JP 2976988A JP H0445336 B2 JPH0445336 B2 JP H0445336B2
- Authority
- JP
- Japan
- Prior art keywords
- temperature
- stretching
- polyester film
- longitudinal direction
- relaxation
- 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
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- Shaping By String And By Release Of Stress In Plastics And The Like (AREA)
Description
〔産業上の利用分野〕
この発明は、温度膨張係数の等方性が改良され
たポリエステルフイルムを得ることのできるポリ
エステルフイルムの製法に関する。
〔従来の技術〕
ポリエステルフイルムは、一般に、つぎのよう
にしてつくられている。ポリエステル樹脂を押出
機に供給して溶融押し出しし、口金でシート状に
成形する。これを冷却ドラムに巻きつけて冷却固
化することにより、未延伸シートをつくる。この
未延伸シートを90℃の一定温度で縦方向に延伸す
る。つぎに、第２図に示されているように、100
℃の一定温度で横方向に延伸する。このあと、
170〜220℃でテンター幅一定の緊張熱処理を行
い、冷却を行つてポリエステルフイルムを得るの
である。このポリエステルフイルムは、必要に応
じて、所定の幅にスリツトされて巻き取られる。
なお、上記緊張熱処理ののち、横方向の熱収縮改
善を目的として横方向リラツクスを行うことがあ
る。
〔発明が解決しようとする課題〕
このようにして得られたポリエステルフイルム
には、端部の温度膨張係数の等方性が悪いという
問題があつた。すなわち、前記ポリエステルフイ
ルムの温度膨張係数には、方向によつて異なる
が、端部においてその最大値と最小値の差Δαtが
大きいと言う問題があつたのである。これは、ポ
リエステルフイルムの幅が広いほど顕著であつ
た。
発明者らが調べたところによると、ポリエステ
ルフイルム端部のΔαtを小さくするには、緊張熱
処理温度を下げることが有効であるが、その効果
が充分でない上に、緊張熱処理温度を下げると、
ポリエステルフイルムの熱収縮率が上昇して実用
に適さなくなる。熱収縮率を下げるには、緊張熱
処理温度を高くするのがよいが、このようにする
と、フイルム端部のΔαtが大きくなつてしまうと
いう問題が生じる。
この発明は、このような事情に鑑みてなされた
ものであつて、ポリエステルフイルム端部 の温
度膨張係数の等方性を向上させることができ、し
かも、必要に応じて、熱収縮率を小さくすること
もできるポリエステルフイルムの製法を提供する
ことを課題としている。
〔課題を解決するための手段〕
前記のような課題を解決するため、この発明
は、延伸工程における横方向の延伸を90℃以上の
温度から始めて以後10℃／秒以下の速度で必要最
高温度まで昇温しながら行うようにする。また、
この横延伸工程ののちに、80℃〜120℃で縦方向
に0.1〜1.0％リラツクスさせるリラツクス工程を
も経るようにするか、まず、横延伸工程の最高温
度以下で横方向に0.5〜６％リラツクスさせ、そ
の後、80℃〜120℃で縦方向に0.1〜1.0％リラツ
クスさせるリラツクス工程をも経るようにする。
〔作用〕
横延伸工程を、90℃以上の温度から始めて以後
10℃／秒以下の速度で必要最高温度まで昇温しな
がら行うようにすると、得られたポリエステルフ
イルムは、端部のΔαtが小さくなり、温度膨張係
数の等方性が優れたものとなる。前記横延伸工程
ののちに、80℃〜120℃で縦方向0.1〜1.0％のリ
ラツクスを行うようにすると、得られたポリエス
テルフイルムは、温度膨張係数の等方性が優れる
とともに、縦方向の熱収縮率が低いものとなる。
前記縦方向のリラツクス工程に先立ち、横延伸工
程の最高温度以下で横方向0.5〜６％のリラツク
スを行うようにすると、得られたポリエステルフ
イルムは、横方向の熱収縮率も縦方向の熱収縮率
も低いフイルムとなる。
〔実施例〕
この発明にかかるポリエステルフイルムの製法
は、たとえば、つぎのようにして実施される。ま
ず、従来と同様、ポリエステル樹脂を押出機に供
給して溶融押し出しし、口金でシート状に成形す
る。これを冷却ドラムに巻きつけて冷却固化する
ことにより、未延伸シートをつくる。この未延伸
シートに対してつぎの延伸工程を行う。まず、縦
方向に延伸する。このときの温度は90〜120℃と
するのが好ましく、延伸倍率は3.2倍以上とする
のが好ましい。つぎに、一旦、冷却を行う。この
冷却は25℃程度までとするのが好ましい。このの
ち、90℃以上の温度に加熱し、第１図に示されて
いるように、この温度から始めて以後10℃／秒以
下の速度で必要最高温度まで昇温しながら横方向
に延伸する。このときの昇温速度は５℃／秒以下
が好ましい。上記昇温速度は、必ずしも一定であ
る必要はなく、平均昇温速度が前記の値を越えな
ければ、段階的な昇温でも良い。平均昇温速度
は、たとえば、ポリエステルフイルム製造工程の
テンター内に縦方向長さ5mあたり１ケ所以上の
温度測定点を設けて、製造中のフイルム自体また
はフイルム近傍の雰囲気温度を測定し、各測定点
間の温度差をその区間のフイルム通過時間で除し
た値をその区間の平均昇温速度とする方法で測定
される。前記必要最高温度は、170℃以上が好ま
しい。このあとで通常行われるテンター幅一定の
緊張熱処理は必要としない。このあと、必要に応
じてリラツクス工程を行う。このリラツクス工程
としては、まず、前記必要最高温度以下で横方向
0.5〜６％のリラツクスを行う。つぎに、80℃〜
120℃で、縦方向0.1〜1.0％のリラツクスを行う
ようにする。前記横方向リラツクスを行わずに、
直ちに冷却し80℃〜120℃として縦方向リラツク
スを行うようにしてもよい。このようにして、ポ
リエステルフイルムを得る。このポリエステルフ
イルムは、従来と同様、必要に応じて、所定の幅
にスリツトされて巻き取られる。つぎに、より具
体的な実施例を比較例と併せて説明する。
（実施例 １）
ポリエステルを押出機に供給して溶融押し出し
し、口金でシート状に成形した。これを冷却ドラ
ムに巻きつけて冷却固化することにより、未延伸
シートをつくつた。この未延伸シートを100℃で
縦方向に延伸した。このときの延伸倍率は3.3倍
とした。つぎに、一旦、25℃に冷却した。このの
ち、100℃に加熱し、第１図に示すように、この
温度より始めて3.4℃／秒の速度で210℃まで昇温
しながら横方向に延伸した。このときの延伸倍率
は3.7倍とした。このあと、横延伸最高温度以下
で横方向６％のリラツクスを行つた。100℃まで
冷却したのち、縦方向0.2％のリラツクスを行つ
た。このようにして、幅4mのポリエステルフイ
ルムを得た。
（実施例 ２）
縦方向のリラツクスを行わないほかは、実施例
と同様にして、幅4mのポリエステルフイルムを
得た。
（実施例 ３）
横方向延伸の際、2.5℃／秒の速度で昇温させ
て最高温度を180℃としたほかは、実施例１と同
様にして、幅4mのポリエステルフイルムを得た。
（比較例 １）
実施例１と同様にして未延伸シートをつくつ
た。この未延伸シートを90℃で縦方向に延伸し
た。このときの延伸倍率は3.3倍とした。つぎに、
25℃に冷却した。こののち、100℃に加熱し、第
２図に示すように、この温度で横方向に延伸し
た。このときの延伸倍率は3.7倍とした。つぎに、
220℃に昇温してこの温度でテンター幅一定とし
て緊張熱処理を行つた。さらに、緊張熱処理の最
高温度以下で横方向６％のリラツクスを行い、幅
4mのポリエステルフイルムを得た。
（比較例 ２）
熱処理を200℃で行うようにしたほかは、比較
例１と同様にして、幅4mのポリエステルフイル
ムを得た。
（比較例 ３）
横方向のリラツクスののち、100℃まで冷却し、
縦方向0.2％のリラツクスを行うようにしたほか
は、比較例１と同様にして、幅4mのポリエステ
ルフイルムを得た。
（比較例 ４）
横方向のリラツクスののち、100℃まで冷却し、
縦方向0.2％のリラツクスを行うようにしたほか
は、比較例２と同様にして、幅4mのポリエステ
ルフイルムを得た。
実施例１〜３および比較例１〜４で得られたポ
リエステルフイルムにつき、端部のΔαtおよび熱
収縮率を測定した。その結果を第１表に示す。
温度膨張係数の差Δαtおよび熱収縮率は、つぎ
のようにして測定した。
温度膨張係数の差Δαtの測定方法
あらかじめ偏光顕微鏡によつて求めた光学的配
向方向（長軸）とその直行方向（短軸）に沿つて
長さ150mm、幅10mmの試験片を１本ずつ採取し、
恒温恒湿槽内のTMA装置にセツトしてエージン
グした後、20℃〜30℃における寸法変化を測定
し、以下の式によつて各方向の温度膨張係数を求
める。
温度膨張係数＝寸法変化／サンプル長／温度変化×106
（単位：10-6／℃）
温度膨張係数は、方向によつて異なるが、長軸
方向でほぼ最小、短軸方向でほぼ最大となること
が知られている。
Δαtは、以下の式によつて求められる。
Δαt＝〔短軸方向の温度膨張係数〕−〔長
軸方向の温度膨張係数〕
熱収縮率の測定方法
試験片は、巾10mm、長さ300mmの大きさのもの
を縦横各方向から採取する。測定間隔の標線を試
験片に入れ、カセドメーターを用いるか、あるい
は、これに準ずる方法で原長を測定する。
原長測定後80±１℃に保持された熱風循環式オ
ーブンに試験片をいれ、30分後に取り出し、約10
分間放冷する。この試験片を再びカセドメーター
を用いるか、あるいはこれに準ずる方法で測定す
る。各試験片の平均値を求め次式で熱収縮率を求
める。
熱収縮率＝原長（mm）−熱処理後の長さ（mm
）／原長（mm）×100
[Industrial Field of Application] The present invention relates to a method for producing a polyester film that is capable of obtaining a polyester film with improved isotropy in thermal expansion coefficient. [Prior Art] Polyester films are generally produced in the following manner. The polyester resin is fed into an extruder, melted and extruded, and formed into a sheet using a die. This is wound around a cooling drum and cooled and solidified to produce an unstretched sheet. This unstretched sheet is stretched in the longitudinal direction at a constant temperature of 90°C. Next, as shown in Figure 2, 100
Stretch in the transverse direction at a constant temperature of °C. after this,
A tension heat treatment is performed at 170 to 220°C with a constant tenter width, followed by cooling to obtain a polyester film. This polyester film is slit to a predetermined width and wound up, if necessary.
Note that, after the tension heat treatment, lateral relaxation may be performed for the purpose of improving lateral heat shrinkage. [Problems to be Solved by the Invention] The polyester film thus obtained had a problem in that the isotropy of the thermal expansion coefficient at the end portions was poor. That is, although the temperature expansion coefficient of the polyester film differs depending on the direction, there is a problem in that the difference Δα t between the maximum value and the minimum value is large at the end portions. This was more noticeable as the width of the polyester film was wider. According to the inventors' investigation, lowering the tension heat treatment temperature is effective in reducing Δα t at the edge of a polyester film, but the effect is not sufficient, and if the tension heat treatment temperature is lowered,
The heat shrinkage rate of the polyester film increases, making it unsuitable for practical use. In order to lower the thermal shrinkage rate, it is better to increase the tension heat treatment temperature, but if this is done, a problem arises in that Δα t at the ends of the film increases. This invention was made in view of the above circumstances, and it is possible to improve the isotropy of the coefficient of thermal expansion of the end portion of a polyester film, and also to reduce the coefficient of thermal contraction if necessary. Our objective is to provide a method for manufacturing polyester film that can also be used to produce polyester films. [Means for Solving the Problems] In order to solve the above-mentioned problems, the present invention provides a method in which the lateral direction stretching in the stretching step is started at a temperature of 90°C or higher, and then the required maximum temperature is increased at a rate of 10°C/second or lower. Do this while increasing the temperature. Also,
After this transverse stretching step, either a relaxation step of 0.1 to 1.0% in the longitudinal direction at 80°C to 120°C is performed, or first, 0.5 to 6% in the transverse direction at a temperature below the maximum temperature of the transverse stretching step. It is then allowed to undergo a relaxation process in which it is relaxed by 0.1 to 1.0% in the longitudinal direction at 80°C to 120°C. [Effect] After starting the lateral stretching process at a temperature of 90°C or higher,
If the temperature is raised to the required maximum temperature at a rate of 10°C/sec or less, the resulting polyester film will have a small Δαt at the edges and an excellent isotropic coefficient of thermal expansion. . After the transverse stretching process, the resulting polyester film has excellent isotropy in its thermal expansion coefficient and is resistant to heat in the longitudinal direction when it is relaxed by 0.1 to 1.0% in the longitudinal direction at 80°C to 120°C. The shrinkage rate will be low.
Prior to the longitudinal relaxation step, by performing 0.5 to 6% relaxation in the transverse direction at a temperature below the maximum temperature in the transverse stretching step, the obtained polyester film will have a thermal shrinkage rate in the transverse direction as well as in the longitudinal direction. This results in a film with a low ratio. [Example] The method for producing a polyester film according to the present invention is carried out, for example, as follows. First, as in the past, polyester resin is supplied to an extruder, melted and extruded, and formed into a sheet using a die. This is wound around a cooling drum and cooled and solidified to produce an unstretched sheet. The following stretching process is performed on this unstretched sheet. First, it is stretched in the longitudinal direction. The temperature at this time is preferably 90 to 120°C, and the stretching ratio is preferably 3.2 times or more. Next, cooling is performed once. This cooling is preferably to about 25°C. Thereafter, it is heated to a temperature of 90° C. or higher, and as shown in FIG. 1, starting from this temperature, the film is stretched in the transverse direction while increasing the temperature to the required maximum temperature at a rate of 10° C./second or lower. The temperature increase rate at this time is preferably 5° C./second or less. The temperature increase rate does not necessarily have to be constant, and may be a stepwise temperature increase as long as the average temperature increase rate does not exceed the above value. The average temperature increase rate can be calculated, for example, by setting up one or more temperature measurement points per 5m length in a tenter during the polyester film manufacturing process, and measuring the atmospheric temperature of the film itself or near the film during each measurement. It is measured by dividing the temperature difference between points by the film passage time in that section as the average temperature increase rate in that section. The required maximum temperature is preferably 170°C or higher. There is no need for the tension heat treatment with a constant tenter width, which is usually performed after this. After this, a relaxation step is performed if necessary. In this relaxation process, first, the temperature is lower than the required maximum temperature, and the
Perform 0.5-6% relaxation. Next, 80℃～
Try to relax 0.1-1.0% in the vertical direction at 120℃. Without performing the lateral relaxation,
It may be immediately cooled to 80°C to 120°C and subjected to longitudinal relaxation. In this way, a polyester film is obtained. This polyester film is slit to a predetermined width and wound up as necessary, as in the conventional method. Next, more specific examples will be described together with comparative examples. (Example 1) Polyester was supplied to an extruder, melted and extruded, and formed into a sheet using a die. This was wound around a cooling drum and cooled and solidified to produce an unstretched sheet. This unstretched sheet was stretched in the longitudinal direction at 100°C. The stretching ratio at this time was 3.3 times. Next, it was once cooled to 25°C. Thereafter, the film was heated to 100°C, and as shown in FIG. 1, starting from this temperature, the film was stretched in the transverse direction while increasing the temperature to 210°C at a rate of 3.4°C/sec. The stretching ratio at this time was 3.7 times. After this, relaxation of 6% in the lateral direction was performed at a temperature below the maximum lateral stretching temperature. After cooling to 100°C, 0.2% relaxation in the longitudinal direction was performed. In this way, a polyester film with a width of 4 m was obtained. (Example 2) A polyester film having a width of 4 m was obtained in the same manner as in Example except that the relaxation in the longitudinal direction was not performed. (Example 3) A polyester film with a width of 4 m was obtained in the same manner as in Example 1, except that during the transverse stretching, the temperature was raised at a rate of 2.5° C./sec to reach a maximum temperature of 180° C. (Comparative Example 1) An unstretched sheet was produced in the same manner as in Example 1. This unstretched sheet was stretched in the longitudinal direction at 90°C. The stretching ratio at this time was 3.3 times. next,
Cooled to 25°C. Thereafter, it was heated to 100° C. and stretched in the transverse direction at this temperature, as shown in FIG. The stretching ratio at this time was 3.7 times. next,
The temperature was raised to 220°C, and tension heat treatment was performed at this temperature with a constant tenter width. Furthermore, a 6% relaxation in the lateral direction was performed at a temperature below the maximum temperature of the tension heat treatment, and the width
A 4m polyester film was obtained. (Comparative Example 2) A polyester film with a width of 4 m was obtained in the same manner as in Comparative Example 1, except that the heat treatment was performed at 200°C. (Comparative example 3) After lateral relaxation, cool to 100℃,
A polyester film with a width of 4 m was obtained in the same manner as in Comparative Example 1, except that 0.2% relaxation in the longitudinal direction was performed. (Comparative example 4) After lateral relaxation, cool to 100℃,
A polyester film with a width of 4 m was obtained in the same manner as in Comparative Example 2, except that 0.2% relaxation in the longitudinal direction was performed. For the polyester films obtained in Examples 1 to 3 and Comparative Examples 1 to 4, the Δα t and heat shrinkage rate of the ends were measured. The results are shown in Table 1. The difference in temperature expansion coefficient Δα t and the thermal contraction rate were measured as follows. Method for measuring the difference in thermal expansion coefficient Δα t One test piece with a length of 150 mm and a width of 10 mm is measured along the optical orientation direction (long axis) and the orthogonal direction (short axis) determined in advance using a polarizing microscope. Collect,
After aging by setting in a TMA device in a constant temperature and humidity chamber, dimensional changes at 20°C to 30°C are measured, and the coefficient of thermal expansion in each direction is determined using the following formula. Thermal expansion coefficient = Dimensional change/Sample length/Temperature change x 10 6 (Unit: 10 -6 /℃) The thermal expansion coefficient varies depending on the direction, but it is almost minimum in the long axis direction and almost maximum in the short axis direction. It is known that Δα t is determined by the following formula. Δα t = [Temperature expansion coefficient in the short axis direction] - [Temperature expansion coefficient in the long axis direction] Method for measuring thermal contraction rate A test piece with a width of 10 mm and a length of 300 mm is taken from each direction. . Insert the measurement interval marks into the test piece and measure the original length using a cathedometer or a similar method. After measuring the original length, the specimen was placed in a hot air circulation oven maintained at 80 ± 1℃, and removed after 30 minutes.
Leave to cool for a minute. Measure this test piece again using a cathedometer or a similar method. Find the average value of each test piece and calculate the heat shrinkage rate using the following formula. Heat shrinkage rate = Original length (mm) - Length after heat treatment (mm
)/original length (mm) x 100
ポリエステル未延伸シートを縦方向に延伸した
のち横方向に延伸する延伸工程を含むポリエステ
ルフイルムの製法において、請求項１〜３記載の
発明は、前記延伸工程における横方向の延伸を90
℃以上の温度から始めて以後10℃／秒以下の速度
で必要最高温度まで昇温しながら行うようにして
いるので、ポリエステルフイルム端部の温度膨張
係数の等方性を向上させることができる。請求項
２記載の発明は、同横延伸工程ののち、80℃〜
120℃で縦方向に0.1〜1.0％リラツクスさせるリ
ラツクス工程をも経るようにしているので、ポリ
エステルフイルムの縦方向の熱収縮率をも低下さ
せることができる。請求項３記載の発明は、同横
延伸工程ののち、まず、横延伸工程の最高温度以
下の温度で横方向に0.5〜６％リラツクスさせ、
その後、80℃〜120℃で縦方向に0.1〜1.0％リラ
ツクスさせるリラツクス工程をも経るようにして
いるので、ポリエステルフイルムの縦方向の熱収
縮率も横方向の熱収縮率も低下させることができ
る。
In the method for producing a polyester film, which includes a stretching step of stretching an unstretched polyester sheet in the longitudinal direction and then stretching it in the lateral direction, the invention according to claims 1 to 3 provides that the stretching in the lateral direction in the stretching step is carried out at 90°C.
Since the heating is started at a temperature of .degree. C. or higher and then raised to the required maximum temperature at a rate of 10.degree. C./second or less, it is possible to improve the isotropy of the thermal expansion coefficient at the end of the polyester film. In the invention according to claim 2, after the same transverse stretching step, the temperature of 80°C to
Since the polyester film also undergoes a relaxation step of 0.1 to 1.0% relaxation in the longitudinal direction at 120°C, the heat shrinkage rate of the polyester film in the longitudinal direction can also be reduced. The invention according to claim 3 provides that after the transverse stretching step, the material is first relaxed by 0.5 to 6% in the transverse direction at a temperature below the maximum temperature of the transverse stretching step;
After that, we also go through a relaxation process in which the polyester film is relaxed by 0.1 to 1.0% in the longitudinal direction at 80°C to 120°C, which reduces both the longitudinal and lateral heat shrinkage rates of the polyester film. .
第１図はこの発明にかかるポリエステルフイル
ムの製法の１実施例におけるフイルム幅と温度変
化をあらわすグラフ、第２図は従来のポリエステ
ルフイルムの製法におけるフイルム幅と温度変化
をあらわすグラフである。
FIG. 1 is a graph showing the film width and temperature change in one embodiment of the polyester film manufacturing method according to the present invention, and FIG. 2 is a graph showing the film width and temperature change in the conventional polyester film manufacturing method.
Claims (1)
たのち横方向に延伸する延伸工程を含むポリエス
テルフイルムの製法であつて、前記延伸工程にお
ける横方向の延伸を90℃以上の温度から始めて以
後10℃／秒以下の速度で必要最高温度まで昇温し
ながら行うようにすることを特徴とするポリエス
テルフイルムの製法。 ２ ポリエステル未延伸シートを縦方向に延伸し
たのち横方向に延伸する延伸工程を含むポリエス
テルフイルムの製法であつて、前記延伸工程にお
ける横方向の延伸を90℃以上の温度から始めて以
後10℃／秒以下の速度で必要最高温度まで昇温し
ながら行うようにし、かつ、同横延伸工程のの
ち、80℃〜120℃で縦方向に0.1〜1.0％リラツク
スさせるリラツクス工程をも経るようにすること
を特徴とするポリエステルフイルムの製法。 ３ ポリエステル未延伸シートを縦方向に延伸し
たのち横方向に延伸する延伸工程を含むポリエス
テルフイルムの製法であつて、前記延伸工程にお
ける横方向の延伸を90℃以上の温度から始めて以
後10℃／秒以下の速度で必要最高温度まで昇温し
ながら行うようにし、かつ、同横延伸工程のの
ち、まず、横延伸工程の最高温度以下の温度で横
方向に0.5〜６％リラツクスさせ、その後、80℃
〜120℃で縦方向に0.1〜1.0％リラツクスさせる
リラツクス工程をも経るようにすることを特徴と
するポリエステルフイルムの製法。[Scope of Claims] 1. A method for producing a polyester film, which includes a stretching step of stretching an unstretched polyester sheet in the longitudinal direction and then stretching it in the transverse direction, wherein the stretching in the transverse direction in the stretching step is performed at a temperature of 90°C or higher. A method for producing a polyester film, which is characterized in that the process is performed while increasing the temperature to the required maximum temperature at a rate of 10°C/second or less. 2. A method for producing a polyester film that includes a stretching step of stretching an unstretched polyester sheet in the longitudinal direction and then stretching it in the transverse direction, wherein the stretching in the transverse direction in the stretching step is started at a temperature of 90° C. or higher and thereafter at a rate of 10° C./sec. The stretching process should be carried out while raising the temperature to the required maximum temperature at the following speed, and after the same transverse stretching process, a relaxing process of relaxing 0.1 to 1.0% in the longitudinal direction at 80°C to 120°C should be carried out. Characteristic polyester film manufacturing method. 3. A method for producing a polyester film, which includes a stretching step of stretching an unstretched polyester sheet in the longitudinal direction and then stretching it in the transverse direction, wherein the stretching in the transverse direction in the stretching step is started at a temperature of 90°C or higher and thereafter at a rate of 10°C/sec. The temperature should be increased to the required maximum temperature at the following speed, and after the same transverse stretching process, the film should be relaxed by 0.5 to 6% in the transverse direction at a temperature below the maximum temperature of the transverse stretching process, and then 80% ℃
A method for producing a polyester film, characterized in that it also undergoes a relaxation process of 0.1 to 1.0% relaxation in the longitudinal direction at ~120°C.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP2976988A JPH01204723A (en) | 1988-02-10 | 1988-02-10 | Manufacture of polyester film |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP2976988A JPH01204723A (en) | 1988-02-10 | 1988-02-10 | Manufacture of polyester film |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPH01204723A JPH01204723A (en) | 1989-08-17 |
| JPH0445336B2 true JPH0445336B2 (en) | 1992-07-24 |
Family
ID=12285247
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP2976988A Granted JPH01204723A (en) | 1988-02-10 | 1988-02-10 | Manufacture of polyester film |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JPH01204723A (en) |
Families Citing this family (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| KR0158242B1 (en) * | 1994-07-04 | 1999-01-15 | 안시환 | Manufacturing method of thermoplastic resin film |
| JPH08132523A (en) * | 1994-11-09 | 1996-05-28 | Toray Ind Inc | Low heat shrinkable polyester film |
| JPH08164558A (en) * | 1994-12-15 | 1996-06-25 | Toray Ind Inc | Polyester film |
| JP5512759B2 (en) * | 2011-09-16 | 2014-06-04 | 富士フイルム株式会社 | Method for producing biaxially stretched thermoplastic resin film |
-
1988
- 1988-02-10 JP JP2976988A patent/JPH01204723A/en active Granted
Also Published As
| Publication number | Publication date |
|---|---|
| JPH01204723A (en) | 1989-08-17 |
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