JPH07178810A - Biaxially oriented polyester film roll - Google Patents

Abstract

PURPOSE:To obtain a biaxially oriented polyester film roll generating no meandering or lateral shift in a film processing process and excellent in processing stability by specifying the difference of TMA elongation between both sides. CONSTITUTION:In a biaxially oriented polyester film roll, TMA elongation at 100 deg.C is 0.001% or more and the difference of TMA elongation between both sides at 100 deg.C is set to 0.1% or less. TMA elongation is measured by reading dimensional elongation at a time when a sample with width of 5mm and length of 20mm to which load of 30g is applied is heated from the normal temp. at a temp. rising speed of 30 deg.C/min to reach 100 deg.C. With respect to the difference of TMA elongation, TMA elongations of both samples taken from the parts within 50mm from both ends of the film roll are measured and the difference between both measured values is calculated. Therefore, the edge temp. of the film heat-treated after stretching and grasped by a clip is set to 140 deg.C and the temp. of the film from which an edge is removed is set to 130 deg.C or lower and the temp. difference between the edge and the film is set to 50 deg.C or lower.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a biaxially oriented polyester film roll which is free from meandering or deviation in the film processing step and is excellent in processing stability.

[0002]

2. Description of the Related Art Biaxially oriented polyester films are widely used in various applications such as magnetic tapes, adhesive tapes, printed products, electrical insulating products, and photographic image receiving bases because of their dimensional stability. However, the biaxially oriented polyester film roll has characteristic unevenness in the width direction, which causes meandering or deviation in the film processing step,
It caused processed products of unstable quality such as uneven coating and wrinkles. In particular, the wider the width of the biaxially oriented polyester film roll is, the more unstable it is. Further, the part close to the edge of the production of the biaxially oriented polyester film, that is, the film roll having a main orientation direction of 5 to 85 ° with respect to the longitudinal direction is more preferable. It was unstable. For example, JP-A-55-95517 has been proposed as an attempt to improve such meandering and deviation.
Further, as an attempt to improve the characteristic unevenness in the width direction, for example, Japanese Examined Patent Publication No. Sho 63-36972 has been proposed, but the essence of the characteristic unevenness in the width direction which causes meandering or deviation has not been elucidated and it has not been sufficiently improved. .

[0003]

The present invention has clarified the essence of this characteristic unevenness in the width direction, and has a biaxially oriented polyester film roll which is free from meandering and unevenness in the film processing step and has excellent processing stability. The purpose is to provide.

[0004]

The biaxially oriented polyester film roll of the present invention which meets this object has a TMA elongation at 100 ° C. of 0.001% or more, and
It is composed of a material having a difference of 0.1% or less on both sides of TMA elongation at 00 ° C.

The biaxially oriented polyester film in the present invention is a film stretched and oriented in the longitudinal and transverse directions,
A polyester film represented by polyethylene terephthalate, polybutylene terephthalate, polyethylene naphthalate or a polyester film of a copolymer thereof. Alternatively, a laminated film or a strengthened film of these may be used. The film may contain internally precipitated particles produced during polyester polymerization and inert inorganic particles or organic particles represented by calcium carbonate, aluminum oxide, silicon oxide, titanium oxide and the like.

The biaxially oriented polyester film roll of the present invention has a TMA elongation at 100 ° C. of not less than 0.001% and a difference between the two sides of TMA elongation at 100 ° C. of not more than 0.1%. is necessary. TM
The A elongation is a value measured by the method described below, and is different from the one-sided elongation, the thermal dimensional change, the crystallinity, etc. which have been conventionally proposed as the characteristic unevenness in the width direction, and the temperature rising rate, the temperature,
It represents the essence of characteristic unevenness in the film processing process such as time and tension, and as a result of intensive studies, the present invention has been accomplished.

If the TMA elongation is less than 0.001% or shrinks, it is not preferable because it causes tears and wrinkles in the film processing step. A more preferable range of TMA elongation is 0.005% to 0.3%, and a further preferable range is 0.01% to 0.2%.

If the difference between the two sides of TMA elongation at 100 ° C. is larger than 0.1%, the film will be meandered or offset in the film processing step, which is not preferable. TM
A more preferable range of the difference in A elongation is 0.0% to 0.05.
%, And a more preferable range is 0.0% to 0.02%.

The present invention is particularly effective for a film roll having a width of 0.3 m or more, more preferably 0.6 m or more. When the width is small, the tension in the film processing step overcomes the characteristic unevenness in the width direction, and the meandering or deviation in the film processing step is reduced, which tends to reduce the effectiveness of the present invention.

Further, according to the present invention, the main orientation direction with respect to the longitudinal direction at a portion close to the edge, that is, at least one end portion in the film production is in the range of 5 ° to 85 °, more preferably 8 ° to 82 °. It is particularly effective in the case of a film roll.

In the present invention, the elongation value of the film is 10
mm or less, and more preferably 0 mm to 8 mm. When this value is large, the meandering in the film processing step tends to increase.

In the present invention, the heat shrinkage ratio of the film in the longitudinal direction at 80 ° C. for 30 minutes is preferably 0.3% or less, more preferably 0.25% to −0.05%.
When this value is large, there is a tendency that film tearing becomes large.

Next, the manufacturing method of the present invention will be explained, but the present invention is not limited to this. A polyester raw material such as polyethylene terephthalate is melt-extruded with an extruder and cooled, and this is stretched lengthwise and widthwise. Magnification is 3.0 vertically
It is usually 6.0 times, and 3.2 to 4.5 in the horizontal direction, and this may be further longitudinally stretched and laterally stretched. After this, heat treat with a tenter, clip off, and then relax vertically. At this time, the temperature of the edge gripped by the clip is 140 ° C.
Below, the temperature of the film excluding the edges is 130 ° C or less,
In addition, the temperature difference between the edge and the film is preferably kept within 50 ° C. Then cool to room temperature to remove the edges,
It is wound up, slitted, and wound up on a core to obtain a biaxially oriented polyester film roll. The relaxation rate is usually 0.01% to 3.0%. Alternatively, a film roll having a TMA elongation of less than 0.01% is once placed in a heating oven to apply tension, or
A film roll with a difference in MA elongation of more than 0.1%,
It is also possible to take a method of once putting in a heating oven and heating with low tension.

[0014]

[Measurement method of physical properties and evaluation method of effect] Measurement method,
The evaluation method will be described.

1. TMA elongation A sample having a width of 5 mm and a length of 20 mm is loaded with a load of 30 g and heated at a temperature rising rate of 30 ° C./minute from room temperature to 100.
Read the dimensional elongation when reaching ℃. As the measuring device, for example, TM7000 manufactured by Vacuum Riko Co., Ltd. can be used. The average of both sides of the film roll was taken.

2. Difference in TMA Elongation Samples are taken from portions within 50 mm from both ends of the film roll, the TMA elongations of both samples are measured, and the difference between the two is taken as the difference in TMA elongation. 3. Main orientation direction The direction in which the refractive index measured by Abbe's refractometer was the maximum in the film plane.

4. Single-elongation value of film As shown in FIG. 1, the film 10m was taken out from the film roll, placed on a flat plate, air between the film and the flat plate was removed, and then a thread was wound from end to end of the film 10m,
The distance d (mm) between the film and the thread at the center of 5 m was taken as the half-stretch value of the film.

5. Heat Shrinkage A sample cut into a length of 20 cm and a width of 10 mm in the longitudinal direction of the film was left in a hot air oven at 80 ° C. for 30 minutes, then taken out and returned to room temperature, and the heat shrinkage was calculated from the dimensional change before and after heating. It was

6. After applying the meandering film roll of the film to the coater to start coating,
The deviation of the position of the film with respect to the coater was meandering.

7. Coating unevenness and wrinkles A fluorescent lamp was applied to the coated film from above and below, and the presence or absence of coating unevenness and wrinkles was visually observed from the reflected light and transmitted light.

[0021]

【Example】

Example 1 A polyethylene terephthalate resin was melted at 280 ° C. with an extruder, extruded and cooled to 25 ° C. to obtain an unstretched film of 160 μm. This was stretched 3.3 times in the lengthwise direction and 3.8 times in the width direction, and further stretched 1.5 times in the lengthwise direction.
After heat treatment for 2 seconds, after clipping off, 0.3% vertically
relaxed. The temperature of the film was 90 ° C., and the temperature of the clip edge portion was 110 ° C. After that, it is cooled to room temperature, the edges are removed, and it is rolled up to have a thickness of 8 μ and a width of 350 μm.
A 0 mm film was obtained. This was slit into 4 sections and the film at the end was wound around a core for 10000 m to obtain a biaxially oriented polyester film roll having a width of 800 mm. The main orientation direction with respect to the longitudinal direction on the side near the edge of this roll was 25 °. The TMA elongation of the film roll at 100 ° C. is 0.03% on the side close to the edge and 0.035% on the other side.
%, And the difference in TMA elongation at 100 ° C. on both sides was 0.005%. The single elongation value of the film was 3 mm, and the heat shrinkage ratio of the film in the longitudinal direction at 80 ° C. for 30 minutes was 0.2%. A magnetic tape coating liquid having a concentration of 20% was applied to a thickness of 5 μm on a coater using this film roll, and the coating was heated to 110 ° C. and dried. .

Comparative Example 1 A biaxially oriented polyester film roll having a width of 800 mm was obtained in the same manner as in Example 1 except that the longitudinal relaxation was set to 0.1% and the temperature of the clip edge portion was set to 160 ° C. The main orientation direction with respect to the longitudinal direction on the side near the edge of this roll was 25 °. The TMA elongation at 100 ° C. of the film roll is 0.07% on the side close to the edge and −0.0 on the other side.
8%, and the difference in TMA elongation at 100 ° C. on both sides was 0.15%. The single-sided elongation value of the film was 17 mm, and the heat shrinkage ratio of the film in the longitudinal direction at 80 ° C. for 30 minutes was 0.4%. The film roll was coated on a coater with a magnetic tape coating solution having a concentration of 20% by 5 μm, and the film was heated to 110 ° C. and dried.
The coating film deviated by 5 mm meandering, resulting in a processed product with uneven coating and wrinkles.

Example 2 The biaxially oriented polyester film roll having a width of 800 mm obtained in Comparative Example 1 was placed in a heating oven at 100 ° C. and heated at a tension of 5 kg / m for 5 seconds and wound up. The main orientation direction with respect to the longitudinal direction on the side near the edge of this roll was 25 °. Film roll 10
The TMA elongation at 0 ° C is 0.05% on the side close to the edge and 0.03% on the other side, and the difference in TMA elongation at 100 ° C on both sides is 0.02%.
Met. Moreover, the single-elongation value of the film was 5 mm, and the heat shrinkage ratio of the film in the longitudinal direction at 80 ° C. for 30 minutes was 0.1%. Apply this film roll to a coater to get a density of 2
5 μ of 0% magnetic tape coating liquid was applied, and the film was heated to 110 ° C. and dried, but the film meandering was 3 mm or less, and a processed product without coating unevenness and wrinkles was obtained.

[0024]

EFFECTS OF THE INVENTION By increasing the value of TMA elongation at 100 ° C. and decreasing the difference between both sides, the meandering and deviation of the film in the film processing steps such as coating, drying, laminating, vapor deposition and winding. Disappeared,
A stable processed product was obtained.

[Brief description of drawings]

FIG. 1 shows a method for measuring a piece elongation value of a film.

[Explanation of symbols]

 1. Film 2. yarn

Claims (3)

[Claims] 1. The TMA elongation at 100 ° C. is 0.00.
A biaxially oriented polyester film roll, which is 1% or more and has a difference of 0.1% or less on both sides of TMA elongation at 100 ° C. 2. The biaxially oriented polyester film roll according to claim 1, wherein the width of the film roll is 0.3 m or more, and the main orientation direction with respect to the longitudinal direction at at least one end is 5 ° to 85 °. . 3. The biaxially oriented polyester film roll according to claim 1, wherein the film has a single elongation value of 10 mm or less.