JP5332234B2 - Polyethylene terephthalate resin film roll and method for producing the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a polyethylene terephthalate resin film roll which has good film transparency in a heat treatment process during post-processing over the whole length of the roll irrespective of the conditions of the post-processing and high practicability. <P>SOLUTION: In the biaxially oriented polyethylene terephthalate resin film roll, the difference &Delta;n<SB>ab</SB>between the refractive index in the angle direction at 45&deg; to the winding direction and the refractive index in the angle direction perpendicular to the winding direction is 0.015-0.060, the thermal shrinkage rate HS180 in the longitudinal direction at 180&deg;C for 30 min is at least 0.4% and below 1.15%, and a difference in HS180 in the width direction is 0.10% or below. <P>COPYRIGHT: (C)2009,JPO&amp;INPIT

Description

  The present invention relates to a polyethylene terephthalate-based resin film roll, and more particularly to a polyethylene terephthalate-based resin film roll that has excellent processing characteristics and can be widely used in applications with severe thermal dimensional stability. is there.

  Biaxially oriented polyethylene terephthalate resin films are widely used as various optical films because of their excellent transparency, dimensional stability, and chemical resistance. In particular, it is suitably used for applications such as a prism lens sheet base film, an antiglare film base film, and a CRT anti-fracturing film for LCDs that require excellent strength and dimensional stability. Such a biaxially stretched polyethylene terephthalate resin film is stretched in the longitudinal direction between rolls having a difference in rotational speed, and then stretched in the width direction with the end of the film held in the tenter. It is manufactured by being heat-fixed at. Therefore, since the relaxation in the longitudinal direction cannot be promoted particularly at the edge of the film in the width direction at the end of the film, the thermal contraction rate in the longitudinal direction varies depending on the position of the slit roll in the film width direction. End up. Therefore, among the slit rolls that have slit the mill roll once wound in a wide width, in the slit roll corresponding to the edge of the mill roll, the heat shrinkage rate (the heat shrinkage rate in the longitudinal direction) at the one edge in the width direction is the other. The phenomenon that it becomes larger than the thermal contraction rate at the edge occurs. And if such a distorted slit roll is used, the permeability of the film in the heat treatment process during post-processing such as prism lens processing, hard coat processing, and anti-glare (AR) processing is deteriorated, and the film is in the post-processing step. The situation which damages an edge part by rubbing with the frame of a machine stand, etc. will occur inside. Moreover, it is very troublesome to adjust the post-processing conditions on the user side so that the film is not damaged. As the slit roll corresponding to the edge of the mill roll is difficult to use for optical applications, only slit rolls other than the edge of the mill roll are used for optical applications and the post-processing conditions are not adjusted for optical applications. Could not be used.

In addition, even when the film does not pass through the heat process continuously as described above, heat may be applied on the sheet, such as various commercial printing, electric decoration board, dummy can, There are labels. In addition, when applying ITO vapor deposition to a film such as a transparent touch panel application, it is necessary to sufficiently reduce the contraction rate in the longitudinal direction through a heating annealing process. When this shrinkage amount is large, the film is often shrunk and its dimensions are changed when a product using the ITO film as a member is heated. In applications where the dimensional change of the ITO film to be used is particularly unfavorable, it is also used after performing an annealing treatment again before processing.

  Besides these, for example, when used for the following applications, it is desired that the film has a low thermal shrinkage. When the hard coat film is thermally processed (for example, heated at about 150 ° C. for about 1 minute), if the difference between the shrinkage rate of the hard coat and the heat shrinkage rate of the film substrate is large, there is a problem that the film is curled. Furthermore, when a flexible printed circuit board (FPC) is manufactured, a heat press treatment (for example, about 165 ° C. for about 10 seconds) may be performed without peeling off the FPC reinforcing film. In the method of peeling and removing the film, there is a problem that curling occurs after hot pressing if the difference in thermal shrinkage between the FPC reinforcing film and the film substrate is large. Furthermore, when multi-color overprinting (for example, at about 160 ° C. for several tens of seconds) is performed on a polyester film substrate, printing displacement occurs due to thermal shrinkage. When the polyester film is vacuum-deposited, the film temperature is exposed to about 160 ° C., but the polyester film may change in dimensions due to such heat. Particularly in the field requiring heat resistance, thermal dimensional stability at higher temperatures (for example, 180 ° C.) is required.

  In addition, there is an increasing demand for wide slit rolls in order to reduce post-processing costs. In order to collect a wide slit roll from a limited mill roll width with good yield, it is desirable to increase the mill roll width. However, when the mill roll is widened, it becomes difficult to maintain temperature uniformity in the width direction of the heat setting device. That is, a temperature difference occurs between the left and right, or the temperature becomes unstable over time. As a result, it becomes difficult to control the heat shrinkage rate constant in the width direction and the longitudinal direction. Therefore, in order to widen the mill roll, it is indispensable to finely adjust the hot air blowing amount and the like in order to maintain good temperature uniformity in the width direction of the heat fixing device. However, even when fine adjustments such as the amount of blown hot air are made, it is not possible to reduce the difference in thermal shrinkage at the film edge to a level sufficient to improve the film passability in post-processing.

  Therefore, regardless of the width of the mill roll, a method for reducing the difference in the heat shrinkage rate in the width direction of the film (the heat shrinkage rate in the longitudinal direction of the film) in order to improve the film passability in the post-processing step In the heat fixing process of the film, the applicant puts a continuous shielding plate on a plenum duct (hot air outlet) arranged at regular intervals with respect to the film traveling direction, and the width of the shielding plate By gradually expanding the film toward the film traveling direction side, the temperature in the width direction of the film is increased from the central part to the end part, and the relaxation amount at the end part approaches the relaxation amount at the central part. It has been proposed (Patent Document 1).

JP 2001-138462 A

  Further, as a method for reducing the difference in the heat shrinkage rate in the width direction of the film, the applicant attached discontinuous shielding plates to the five plenum ducts in the film heat setting step, and from each plenum duct, per unit time Discloses a method of increasing the amount of hot air impinging on the end by increasing the speed of air blown from the plenum duct while keeping the amount of hot air blown to the outside (Patent Document 2).

JP 2002-79638 A

  However, in the method of Patent Document 1 in which a continuous shielding plate is simply put on the plenum duct, the heat treatment in post-processing (coating and drying) is improved to some extent at about 120 ° C. The film relaxation is still inadequate. That is, in the above method, the passability when heat treatment at about 160 ° C. is performed for a relatively long time (10 to 60 seconds) (formation of a hard coat film, etc.) is not improved so much. Therefore, when post-processing is performed at a high temperature for a long time, the conditions must be adjusted, but such adjustment may not be possible.

  In addition, the method of simply covering the plenum duct with the heat setting process increases the temperature hunting (hunting) in the heat setting zone, and thus produces a long film (mill roll) of 1,000 m or more. In doing so, a portion having poor permeability (that is, a portion having a large difference in thermal shrinkage in the width direction of the film) is formed. Also, this method alone could not be achieved to reduce the absolute value of the heat shrinkage rate.

  Furthermore, in the method of Patent Document 2, since the air volume of each plenum duct is constant, the wind speed is different for each plenum duct, so that turbulent flow occurs in the heat fixing device. Therefore, the temperature in the heat setting zone is greatly inhomogeneous, which is inconvenient. Moreover, the effect of reducing the difference in the heat shrinkage rate in the width direction due to the shielding plate was not satisfactory.

In addition, as a method of reducing the thermal shrinkage rate in the longitudinal direction and reducing the curl during post-processing, a method in which the longitudinal treatment is performed in an offline heat treatment process has been proposed (Patent Document 3).

JP 2001-138466 A

  However, although the method of Patent Document 3 is effective for lowering the heat shrinkage value, since the processing is performed off-line, the manufacturing cost becomes high and it is not suitable for the cost reduction request. Therefore, a method for producing a low-shrinkage film by in-line processing (during film formation) is eagerly desired.

  Furthermore, as a method for reducing the thermal shrinkage of the biaxially stretched polyester film, for example, as shown in Patent Document 4, a razor is inserted into the end of the tenter and cut to avoid the influence of the clip, and the relaxation treatment is performed in the longitudinal direction. A method has been proposed. Although this method is not affected by the gripping of the clip, there is a problem that the film is loosened by its own weight during the relaxation process and is damaged by contacting the plenum duct of the tenter. To avoid this, fine adjustment of the upper and lower air balances to prevent scratches impairs the uniformity of the temperature in the oven due to the collapse of the air balance, and the flatness of the film deteriorates or the uniformity is impaired. There's a problem.

Japanese Examined Patent Publication No.57-54290

As another method for reducing the thermal shrinkage of the biaxially stretched polyester film, as shown in Patent Document 5, a method of gradually narrowing the clip interval of the tenter and performing a longitudinal relaxation treatment has been proposed. . However, with this method, the ease of movement of the film at the end and center of the clip differs, and the difference in physical properties between the grip and the center in the longitudinal direction is unavoidable, and it relaxes to reduce the heat shrinkage rate If is increased, the flatness of the film deteriorates and wrinkles occur. In order to eliminate the influence of such wrinkles, the film edge must be greatly trimmed, resulting in poor production efficiency. On the contrary, when the original clip interval is set small in order to suppress the generation of wrinkles, the relaxation is insufficient.

Japanese Patent Publication No. 4-0221818

  The object of the present invention is to solve the problems of the conventional film and the production method thereof, and the film has a good practicality over the entire length of the roll regardless of the conditions of the post-processing, regardless of the post-processing conditions. It is in providing a polyethylene terephthalate-type resin film roll with high. In addition, the object of the present invention is to produce a polyethylene terephthalate-based resin film roll with low heat shrinkage and a low thermal shrinkage in addition to extremely good film permeability in the heat treatment step during post-processing. An object of the present invention is to provide a manufacturing method that can be used.

Among the present inventions, the structure of the first invention is a biaxially stretched polyethylene terephthalate resin film slit to have a length of 300 m to 8,000 m and a width of 0.7 m to 2.2 m. Δn _ab is 0.015 or more, which is the difference between the refractive index in the direction that forms an angle of 45 degrees with the winding direction of the film and the refractive index in the direction that forms an angle of 135 degrees with the winding direction of the film A biaxially stretched polyethylene terephthalate-based resin film roll of 0.060 or less,
The first sample cutout is provided within 2 m from the end of winding of the film, the final cutout is provided within 2 m from the start of winding of the film, and the length between the first and final cutout is divided into nine equal parts. By providing the sample cutout part in the above, when a total of ten sample cutout parts are provided, the following requirements (1) and (2) are satisfied.
(1) When each sample is cut out from a position within 50 mm from one end edge and a position within 50 mm from the other end edge in the roll width direction, and the two samples are heated at 150 ° C. for 30 minutes. HS150, which is the heat shrinkage rate in the winding direction of the film, was obtained, and when the heat shrinkage difference, which is the difference between the HS150, was obtained, the difference in heat shrinkage rate at all the cutout portions was 0.1%. (2) When each of the cutout portions cuts out a sample from a position within 50 mm from one end edge and a position within 50 mm from the other end edge in the roll width direction, and obtains HS150 for each sample. , HS150 of the samples at both end edges in all the cut-out portions is −0.25% or more and 0.25% or less. And

The structure of the second invention is a film obtained by winding a biaxially stretched polyethylene terephthalate resin film slit to have a length of 300 m to 8,000 m and a width of 0.7 m to 2.2 m. Δn _ab, which is the difference between the refractive index in the direction that forms an angle of 45 degrees with the winding direction of the film and the refractive index in the direction that forms an angle of 135 degrees with the winding direction of the film, is 0.015 or more and 0.060 or less. A biaxially stretched polyethylene terephthalate resin film roll,
The first sample cutout is provided within 2 m from the end of winding of the film, the final cutout is provided within 2 m from the start of winding of the film, and the length between the first and final cutout is divided into nine equal parts. By providing the sample cutout portion in the above, when 10 sample cutout portions are provided in total, the following requirements (3) and (4) are satisfied.
(3) When each sample is cut out from a position within 50 mm from one end edge and a position within 50 mm from the other end edge in the width direction of the roll, and the two samples are heated at 180 ° C. for 30 minutes HS180, which is the heat shrinkage rate in the film winding direction, was obtained, and when the heat shrinkage difference, which is the difference between the HS180, was obtained, the heat shrinkage difference in all cutout portions was 0.1% or less. (4) In each of the cutout portions, when a sample is cut out from a position within 50 mm from one end edge and a position within 50 mm from the other end edge in the width direction of the roll, and HS180 is obtained for each sample, HS180 of samples at both end edges in all cutouts is 0.0% or more and less than 1.15%

  According to a third aspect of the present invention, in the above invention, the wound biaxially stretched polyethylene terephthalate resin film has a thickness of 70 μm or more and 400 μm or less.

The structure of 4th invention is a manufacturing method for manufacturing the said biaxially-stretched polyethylene terephthalate-type resin film roll, Comprising: The film-forming process which forms an unstretched sheet | seat by melt-extruding raw material resin from an extruder, , A biaxial stretching process in which the unstretched sheet obtained in the film forming process is biaxially stretched in the machine direction and the transverse direction, a heat setting process in which the film after biaxial stretching is heat-set, and the film after heat setting in the longitudinal direction Including a step of relaxation treatment in the direction, and the heat setting step is performed in a heat setting device that satisfies the following requirements (5) to (8).
(5) A plurality of wide plenum ducts for blowing hot air are arranged vertically opposite to the film traveling direction. (6) Shielding for shielding hot air outlets to the plurality of plenum ducts. (7) The dimension of each shielding plate in the traveling direction of the film is adjusted to be substantially the same as the dimension of the outlet of each plenum duct in the traveling direction of the film. The dimension in the width direction of the film is adjusted so as to become gradually longer with respect to the traveling direction of the film. (8) The air speed of the plenum duct in each heat setting zone is made constant.

  According to a fifth aspect of the present invention, in the step of relaxing in the longitudinal direction, the film edge is cut and separated, and then the drawing speed of the film that has been cut and separated is reduced to reduce the film in the longitudinal direction. It is characterized by performing.

  The structure of the sixth invention is that, in the above invention, the biaxial stretching step stretches the film in the longitudinal direction and then in the transverse direction, and between the zone for performing the transverse stretching and the heat setting device, An intermediate zone that does not execute wind blowing is provided.

  According to a seventh aspect of the present invention, in the above invention, the heat setting device is divided into a plurality of heat setting zones, and the product of the temperature difference and the wind speed difference between adjacent heat setting zones, It is set so that it may become 250 degrees C * m / s or less.

  The structure of the eighth invention is characterized in that, in the above invention, after the longitudinal relaxation treatment, the film is cooled while holding the film edge.

  The polyethylene terephthalate-based resin film roll of the present invention has very high yield because it has excellent post-processing characteristics such as film passability in a heat treatment process such as prism lens processing, hard coat processing, and AR processing. Can be post-processed. Moreover, the thermal dimensional stability in the heat treatment process in the subsequent processing is good. Accordingly, the polyethylene terephthalate-based resin film roll of the present invention is used for various optical members such as a base film for a prism lens sheet, a base film for a backlight, a base film for an AR film, and a crush prevention film for a CRT. It can be suitably used as an optical film or a processing film in which heat treatment in other post-processing is performed for a relatively long time (10 to 60 seconds) in a high-temperature zone (about 160 ° C.).

  The film constituting the polyethylene terephthalate resin film roll of the present invention contains ethylene glycol and terephthalic acid as main components. Other dicarboxylic acid components and glycol components may be copolymerized as long as the object of the present invention is not impaired. Examples of the other dicarboxylic acid components include isophthalic acid, p-β-oxyethoxybenzoic acid, 2,6-naphthalenedicarboxylic acid, 4,4′-dicarboxybenzophenone, bis- (4-carboxyphenylethane), adipine Examples include acid, sebacic acid, 5-sodium sulfoisophthalic acid, cyclohexane-1,4-dicarboxylic acid and the like. Examples of the other glycol component include propylene glycol, butanediol, neopentyl glycol, diethylene glycol, ethylene oxide adducts such as bisphenol A, polyethylene glycol, polypropylene glycol, and polytetramethylene glycol. In addition, oxycarboxylic acid components such as p-oxybenzoic acid can also be used.

  As a polymerization method of such polyethylene terephthalate (hereinafter simply referred to as PET), a direct polymerization method in which terephthalic acid and ethylene glycol and, if necessary, other dicarboxylic acid component and diol component are directly reacted, and dimethyl terephthalate are used. Any production method such as a transesterification method in which an ester (including a methyl ester of another dicarboxylic acid as necessary) and ethylene glycol (including another diol component as necessary) are transesterified can be used. .

  When the film roll of the present invention is formed of PET, the intrinsic viscosity (IV) of the raw material PET is preferably in the range of 0.45 to 0.70 dl / g. When the intrinsic viscosity of the PET raw material is 0.45 or less, the degree of polymerization of the PET after being recovered and passed through the extruder again becomes too low, and the stretchability of the film deteriorates or the tear resistance decreases. Is not preferable. On the other hand, if the intrinsic viscosity exceeds 0.70 dl / g, the filtration pressure becomes excessively high and high-precision filtration becomes difficult, which is not preferable. In addition, IV of resin raw material is calculated | required with the following methods, for example.

[Intrinsic viscosity (IV)]
After the PET ground sample is dried, it is dissolved in a mixed solvent of phenol / tetrachloroethane = 60/40 (weight ratio), and a solution having a concentration of 0.4 (g / dl) is obtained at 30 ° C. using an Ostwald viscometer. The flow time and the flow time of the solvent alone are measured, and the calculation is performed from the time ratio on the assumption that the constant of Huggins is 0.38 using the Huggins formula. The intrinsic viscosity is also expressed as [η].

  Moreover, when forming the film roll of this invention by PET, the range of 3-30 eq / t is preferable and, as for the acid value (AV) of PET raw material, it is more preferable in it being 5-25 eq / t. An acid value of 3 eq / t or less is not preferable because the polymerization rate becomes slow and the production efficiency is lowered. On the other hand, an acid value of 30 eq / t or more is not preferable because hydrolysis tends to proceed and the degree of polymerization tends to decrease. The acid value of the resin raw material is determined by the following method, for example.

[Acid value]
After pulverizing the raw material, it is dissolved in benzyl alcohol, and after adding chloroform, neutralization titration with a sodium hydroxide solution is performed to calculate the equivalent of sodium hydroxide per 1 ton of PET.

Furthermore, when the film roll of the present invention is formed of PET, it is desirable that the raw material resin (including the recycled raw material) does not contain foreign matters. In particular, when producing a film roll for optical applications, high-precision filtration is performed when melt-extruding so that the number of foreign matters having a diameter of 20 μm or more present per 1 m ^{2 of the} film after film formation is 10 or less. It is preferable to adjust. When performing high-precision filtration, it is preferable to use a filter medium having an initial filtration efficiency of 90% or more and a filtration particle size of 15 μm or less. Here, the initial filtration efficiency refers to a numerical value measured by ANSI / B93.36-1973. Note that the number of foreign substances in the raw material is obtained by the following method, for example.

[Number of foreign objects]
An enlarged image of the melted raw material chip is taken using a phase contrast microscope and a CCD camera, and the number of foreign matters is counted using an image processing apparatus.

The polyethylene terephthalate-based resin film roll of the present invention is a slit roll obtained by slitting a mill roll once manufactured in a wide width into a predetermined number, and Δn _ab (that is, an angle of 45 degrees with the winding direction of the wound film). The difference (absolute value) between the refractive index in the forming direction and the refractive index in the direction forming an angle of 135 degrees with the winding direction of the wound film is limited to 0.015 or more and 0.060 or less. . That is, in the slit roll in which Δn _ab is less than 0.015, the above-described problem of “distortion (that is, physical property difference in the width direction)” does not occur. Moreover, in the slit roll distorted so that Δn _ab exceeds 0.060, it is difficult to adjust the difference in heat shrinkage rate so as to satisfy the requirements of the present invention. In addition, Δn _ab in the present invention means Δn _ab which is the larger of the two values when Δn _ab is measured at a position within 50 mm from one edge of the slit roll and a position within 50 mm from the other edge.

  The polyethylene terephthalate-based resin film roll of the present invention has a position within 50 mm from one end edge and a position within 50 mm from the other end edge in the width direction of the roll when each sample cut out part is set by the above-described method. When the sample was cut out from each of the two samples, HS150, which is the heat shrinkage rate in the film winding direction when heated at 150 ° C. for 30 minutes, and the difference in heat shrinkage rate was determined, It is desirable that the heat shrinkage ratio difference (ΔHS150) in all cutout portions is 0.1% or less.

  That is, the polyethylene terephthalate-based resin film roll of the present invention has a total of 10 heat shrinkage difference (ΔHS150) obtained in a total of 10 cutout portions (difference in HS150 at both end edges in a film sample cut out from each cutout portion). However, it is desirable that both be 0.1% or less. If the difference in heat shrinkage rate (ΔHS150) at each cut-out portion exceeds 0.1%, the film passability in post-processing performed in a high temperature zone (for example, about 160 ° C.) is deteriorated, which is not preferable. Moreover, the heat shrinkage ratio difference (ΔHS150) at each cutout is more preferably 0.08% or less, and particularly preferably 0.06% or less. In addition, although the heat shrinkage rate difference in each cutout part is preferably as low as possible, it is considered that about 0.05% is the limit in consideration of measurement accuracy.

The film sample used for the measurement of the heat shrinkage rate is cut out from 10 cutout portions provided by the following procedure.
(1) The first sample cutout is provided within 2 m from the end of winding of the film.
(2) A value obtained by dividing the length of the wound film by 9 (hereinafter, referred to as “cut section interval”) is calculated.
(3) A sample cutout portion is provided at a position within 10 m before and after each “cutout portion interval” from the end of winding of the film.
(4) A final cutout portion is provided within 2 m from the start of film winding.

  The cutting of the sample will be described more specifically. For example, when a film having a length of 500 m is wound around a roll, the first sample (1) is cut within 2 m from the end of winding of the film. The sample is cut out in the film winding direction (longitudinal direction) including the position within 50 mm from one end edge and the position within 50 mm from the other end edge in the roll width direction (direction orthogonal to the film winding direction). (Direction) and a side along the width direction are cut into a rectangular shape (not cut obliquely). Next, the “cutting portion interval” is calculated by dividing the winding length of the film by 9. Note that the “cutout interval” is calculated to the unit of “1 m”. Therefore, as described above, when the winding length is 500 m, 2 m from the winding end where the first cutout portion can be provided and 2 m from the winding start where the final cutout portion can be provided are subtracted from 500 m in advance, and the remaining 496 m is obtained. 55 m divided into nine equal parts is defined as “interval of cutout portions”. Subsequently, the second sample (2) is cut out at a distance of 55 m from the winding end of the film toward the winding start side. Thereafter, similarly, samples are sequentially cut out at intervals of 55 m on the winding start side to obtain a total of 10 samples. That is, the first sample (first sample) is cut out at a position within 2 m from the end of winding, the second sample is cut out at a position near 57 m from the end of winding, and the third sample is cut at a position near 112 m from the end of winding. Similarly, the fourth to ninth samples are cut out at every position 55 m away from the end of winding, and the final sample (10th sample) is cut out at a position within 2 m from the start of winding.

  Furthermore, the polyethylene terephthalate-based resin film roll of the present invention has a position within 50 mm from one end edge in the width direction of the roll and within 50 mm from the other end edge when the sample cut-out part is set by the above-described method. When the sample is cut out from each position and HS150 is obtained for each sample, it is desirable that the HS150 of the samples at both end edges in all cutout portions is −0.25% or more and 0.25% or less. .

  That is, in the polyethylene terephthalate-based resin film roll of the present invention, the HS150 values (total 20 HS150 values) at the both end edges of the cut film samples were -0.25% in all 10 cutout portions. It is desirable that it is 0.25% or less. If the value of HS150 at both ends of the film sample cut out from each cut-out part exceeds 0.5%, it is not preferable because the thermal dimensional change of the film in post-processing increases. When the absolute value of HS150 is 0.25% or less, it can be suitably used in post-processing. The value of HS150 at the both ends of the film sample cut out from each cut-out portion is preferably as the absolute value is small, and can be more suitably used when the absolute value is 0.2% or less.

  The polyethylene terephthalate-based resin film roll of the present invention has a cut-out portion set by a method to be described later. At each cut-out portion, a position within 50 mm from one end edge in the roll width direction and within 50 mm from the other end edge. Samples were cut out from each of the positions, and HS180, which is the heat shrinkage rate in the film winding direction when heated at 180 ° C. for 30 minutes, was measured for the two samples, and the difference in heat shrinkage rate (ΔHS180) as the difference was measured. When obtained, it is necessary that the difference in thermal shrinkage rate at all cutout portions is 0.1% or less.

That is, the polyethylene terephthalate-based resin film roll of the present invention has a total of 10 heat shrinkage difference (ΔHS180) obtained in a total of 10 cutout portions (difference in HS180 at both end edges in a film sample cut out from each cutout portion). However, it is necessary that both be 0.10% or less. Thus, the thermal dimensional stability of the polyethylene terephthalate resin film roll of the present invention is maintained even at higher temperatures. Therefore, it can be suitably used for a post process performed at a high temperature, for example, multi-color overprinting in printing (about 160 ° C. for several tens of seconds). If the difference in thermal shrinkage (ΔHS180) at each cutout exceeds 0.20%, the dimensional change of the film occurs at a high temperature, and printing misalignment occurs due to thermal shrinkage when multicolor overprinting is performed. Therefore, it is not preferable. The heat shrinkage rate difference (ΔHS180) in each cut-out part can be suitably used for the above-mentioned applications when it is 0.10% or less. In addition, although the heat shrinkage rate difference in each cutout part is preferably as low as possible, it is considered that about 0.05% is the limit in consideration of measurement accuracy.

  Furthermore, the polyethylene terephthalate-based resin film roll of the present invention has a position within 50 mm from one end edge in the width direction of the roll and within 50 mm from the other end edge when the sample cut-out part is set by the above-described method. When the sample is cut out from each position and the HS 180 is obtained for each sample, the HS 180 of the samples at both end edges in all cut-out portions must be 0.4% or more and less than 1.15%. is there.

  That is, in the polyethylene terephthalate-based resin film roll of the present invention, the HS 180 values (the total 20 HS 180 values) of both ends of the cut film sample are 0.4% or more in the total of 10 cut portions. It must be less than 1.15%. If the value of HS180 at both ends of the film sample cut out from each cut-out part exceeds 1.15%, it is not preferable because the thermal dimensional change of the film in post-processing (particularly a post-process at a high temperature of about 160 ° C.) becomes large. Moreover, the value of HS180 at the both ends of the film sample cut out from each cut-out part is preferably as the absolute value is small, and about 0.4% is considered to be the lower limit.

  Furthermore, the polyethylene terephthalate-based resin film roll of the present invention has a fluctuation amount of HS180 on one end edge side in the width direction of the roll obtained in each cutout part, and HS180 on the other end edge side in the roll width direction obtained in each cutout part. It is desirable that the fluctuation amount (the fluctuation amount of the heat shrinkage rate in the longitudinal direction) is 0.25% or less. Further, also for the HS 150, it is desirable that the fluctuation amount of the heat shrinkage rate in the longitudinal direction is 0.25% or less.

  That is, the polyethylene terephthalate-based resin film roll of the present invention has HS 180 on one end edge side (one end edge side in the width direction) and HS 180 on the other end side (the other end edge side in the width direction) for 10 films cut out from each cutout portion. , The fluctuation amount (difference between the highest value and the lowest value) of the ten HS 180 on one edge side is 0.25% or less, and the fluctuation amount of the ten HS 180 on the other edge side is 0. It is desirable that it is 25% or less. It is preferable that the fluctuation amount of the ten HS 180 on either edge side is 0.25% or less because the film can be easily passed during post-processing. Further, the fluctuation amount of the ten HS 180 on each edge side is more preferably 0.20% or less, still more preferably 0.18% or less, still more preferably 0.16% or less, and 0.15 % Or less is particularly preferable. In addition, although the variation | change_quantity of 10 HS180 by each edge side is so preferable that it is low, when a measurement precision is considered, about 0.05% is considered to be a limit. The same applies to the HS 150.

  The polyethylene terephthalate-based resin film roll of the present invention is a longitudinal direction (longitudinal direction) and a lateral direction of an unstretched film (unstretched laminated film or unstretched laminated sheet) obtained by melting and extruding a raw material polyethylene terephthalate-based resin chip. After biaxial stretching in the method (width direction), the film can be wound into a roll and heat-fixed by the method described later.

  As a method for obtaining an unstretched sheet, it is desirable that the pellets of polyethylene terephthalate resin containing fine particles for the purpose of imparting slipperiness are sufficiently dried. Furthermore, a polyethylene terephthalate resin containing fine particles for the purpose of imparting slipperiness can also be used suitably.

  In addition, a well-known method can be applied to rapidly cool an unstretched sheet while bringing the sheet-like melt into close contact with the rotary cooling drum. For example, a method of using an air knife on the sheet-like melt or an electrostatic charge can be applied. A method of imprinting is preferably applicable. In those methods, the latter is preferably used.

  As a method of cooling the air surface of the sheet-like material, a known method can be applied. For example, a method of bringing the sheet surface into contact with a cooling liquid in the tank, a liquid evaporating with a spray nozzle on the sheet air surface You may use together the method of apply | coating, and the method of spraying a high-speed airflow and cooling. The unstretched sheet thus obtained is stretched in the biaxial direction to obtain a film.

  As a method of stretching the film in the biaxial direction, the obtained unstretched sheet is stretched in the longitudinal direction by a roll or a tenter-type stretching machine, and then stretched in the width direction orthogonal to the first-stage stretching direction. A method can be mentioned. The stretching temperature in the longitudinal direction is 75 to 120 ° C., and the stretching ratio in the longitudinal direction is 2.5 to 4.5 times, preferably 3.0 to 4.3 times. If the stretching temperature in the longitudinal direction is less than 75 ° C., the film tends to break, which is not preferable. Moreover, since it will worsen the thickness spot of the obtained film when it exceeds 120 degreeC, it is not preferable. When the draw ratio in the longitudinal direction is less than 2.5 times, the flatness of the obtained film is deteriorated, which is not preferable. On the other hand, if it exceeds 4.6 times, the orientation in the longitudinal direction becomes strong, and the frequency of breakage increases in stretching in the transverse direction, which is not preferable.

  In the case of stretching in the width direction, the stretching temperature needs to be 80 to 210 ° C, and preferably 130 to 200 ° C. If the stretching temperature in the width direction is less than 80 ° C., the film tends to break, which is not preferable. Moreover, when it exceeds 210 degreeC, since the planarity of the obtained film worsens, it is not preferable. The draw ratio in the width direction is 3.0 to 5.0 times, preferably 3.6 to 4.8 times. If the draw ratio in the width direction is less than 3.0 times, the thickness unevenness of the obtained film is deteriorated, which is not preferable. If the draw ratio in the width direction exceeds 5.0 times, the frequency of breaking increases in the drawing, which is not preferable.

  Subsequently, heat setting is performed. The temperature in the heat setting treatment step is preferably 180 ° C. or higher and 240 ° C. or lower. If the temperature of the heat setting treatment is less than 180 ° C., the absolute value of the heat shrinkage rate is increased, which is not preferable. On the other hand, if the temperature of the heat setting treatment exceeds 240 ° C., the film tends to become opaque and the frequency of breakage increases, which is not preferable. A suitable heat setting method will be described later.

  It is effective to control the heat shrinkage rate, particularly the heat shrinkage rate in the width direction, by narrowing the guide rail of the gripping tool by the heat setting process. The temperature for the relaxation treatment can be selected in the range from the heat setting treatment temperature to the glass transition temperature Tg of the polyethylene terephthalate resin film, and is preferably (heat setting treatment temperature) −10 ° C. to Tg + 10 ° C. The width relaxation rate is preferably 1 to 6%. If it is less than 1%, the effect is small, and if it exceeds 6%, the flatness of the film is deteriorated.

  Here, although the method of extending | stretching to the width direction after extending | stretching first to a longitudinal direction was described, the extending | stretching order may be reverse. In addition, the longitudinal stretching and the lateral stretching may be performed in one stage, or may be performed in two or more stages. In addition, as described above, in addition to the method of sequentially biaxially stretching an unstretched film, a simultaneous biaxial stretching method in which an unstretched film is simultaneously stretched in the machine direction and the transverse direction can be employed. However, in order to satisfy the characteristics of the present invention, it is important to take optimum temperature conditions and longitudinal and lateral draw ratios, and it is sufficient that the finally obtained film characteristics satisfy the requirements of the present invention.

  Further, in order to impart functionality to the film, a polyethylene terephthalate resin film having a multilayer structure of two or more layers may be used. When the surface on which the slippery layer or the easy adhesion layer is applied is the A layer, the opposite surface is the B layer, and the other surface is the C layer, the layer structure in the film thickness direction is A / B, A / C / B or Configurations such as A / C / E / D / B are conceivable. The layers A to E may be made of the same material or different materials.

  The thickness of the film constituting the polyethylene terephthalate resin film roll of the present invention is not particularly limited. However, when used for optical applications, it is preferable that the thickness is 70 μm or more and 400 μm or less.

  Further, the width of the film roll is not particularly limited, but from the viewpoint of ease of handling, the lower limit of the width of the film roll is preferably 0.7 m or more, and more preferably 1.0 m or more. . On the other hand, the upper limit of the width of the film roll is determined by the size of the customer's device to be post-processed. At present, 2.2 m is considered the maximum width, and it is more preferably 2.0 m or less. More preferably, it is 5 m or less. In addition, the winding length of the film roll is not particularly limited, but from the viewpoint of ease of winding and handling, when the film has a thickness of about 70 μm, it is preferably 8,000 m or less, and 7,000 m or less. Is more preferable. When the film has a thickness of about 400 μm, it is preferably 1,200 m or less, and more preferably 1,100 m or less. Therefore, when the thickness of the film is in the middle of 70 to 400 μm, it is preferable to set the film length to be 300 m or more and 8,000 m or less. As the take-up core, usually, paper of 3 inches, 6 inches, 8 inches, etc., a plastic core or a metal core can be used.

  The polyethylene terephthalate-based resin film of the present invention may be a single layer or a film having a laminated structure of two or more layers, and on one side or both sides of a biaxially stretched polyethylene terephthalate-based resin film that does not contain fine particles with emphasis on transparency. There is no problem even if various coatings are applied at the time of film formation for the purpose of improving the adhesiveness during the post-processing step and the purpose of improving the slipperiness.

  Moreover, in the polyethylene terephthalate-type resin film which comprises the film roll of this invention, microparticles | fine-particles can be added as needed. Examples of the fine particles added at that time include known inorganic fine particles and organic fine particles. Furthermore, in the resin forming the film, various additives as necessary, for example, waxes, antioxidants, antistatic agents, crystal nucleating agents, viscosity reducing agents, heat stabilizers, coloring pigments, An anti-coloring agent, an ultraviolet absorber and the like can be added. It is preferable to add fine particles to the polyethylene terephthalate resin in the present invention to improve the workability (slidability) of the polyethylene terephthalate resin film. Any fine particles can be selected. Examples of inorganic fine particles include silica, alumina, titanium dioxide, calcium carbonate, kaolin, and barium sulfate. Examples of the organic fine particles include acrylic resin particles, melamine resin particles, silicone resin particles, and crosslinked polystyrene particles. The average particle diameter of the fine particles can be appropriately selected as necessary within a range of 0.05 to 2.0 μm.

  As a method of blending the above-mentioned particles into the polyethylene terephthalate resin film, for example, it can be added at any stage of producing the polyethylene terephthalate resin, but preferably after the esterification stage or after completion of the transesterification reaction. It may be added as a slurry dispersed in ethylene glycol or the like at the stage before the start of the condensation reaction to proceed the polycondensation reaction. Also, a method of blending a slurry of particles dispersed in ethylene glycol or water with a vented kneading extruder and a polyethylene terephthalate resin raw material, or a dried particle and a polyethylene terephthalate system using a kneading extruder It can be performed by a method of blending with a resin raw material.

  Furthermore, the polyethylene terephthalate resin film constituting the film roll of the present invention can be subjected to corona treatment, coating treatment, flame treatment, etc. in order to improve the adhesion of the film surface.

  Next, the preferable manufacturing method for obtaining the polyethylene terephthalate-type resin film roll of this invention is demonstrated.

  Usually, the heat setting process of the stretched film is often carried out in a heat setting device in which a plurality of plenum ducts having a long hot air outlet are arranged perpendicular to the longitudinal direction. And in the heat fixing device provided with such a plenum duct, in order to improve the heating efficiency, the air in the heat fixing device is sucked by the circulation fan attached to the heat fixing device, and then sucked. By adjusting the temperature of the air and exhausting it again from the hot air outlet of the plenum duct, "hot air circulation" is performed: "hot air blowing-> suction by a circulation fan-> temperature adjustment of sucked air-> hot air blowing" Is called.

  Further, as described above, the difference in heat shrinkage rate in the width direction of the film roll (difference between HS 150 at the edge of one end and HS 150 at the end of the other end) is the longitudinal direction at the end of the width direction of the film when heat-fixed. This occurs because it is not possible to promote relaxation. As shown in FIG. 1, a method of covering a central portion of the hot air outlets 2, 2,... Of the plenum ducts 3, 3,. In the case of a short film, the passability when the heat setting treatment in the post-processing is performed at a low temperature is improved, but the passability in the long film and the heat setting in the post-processing are improved. The passability when the treatment is performed at a high temperature is not improved at all.

  In order to understand why the method shown in FIG. 1 does not improve the "passability in a long film" or "passability when heat-setting treatment in post-processing is performed at a high temperature", The analysis of the phenomenon in the heat setting device was done in detail. As a result, when a continuous large shielding plate that spans multiple plenum ducts is placed over the hot air outlet of the plenum duct, the flow of hot air is restricted by the shielding plate, and the above-mentioned "hot air circulation" is performed smoothly. As a result, it was found that temperature turbulence (temperature hunting phenomenon) occurred in the heat fixing device.

Since the above-mentioned “temperature hunting phenomenon” causes insufficient thermal relaxation at the edge of the film, the present inventors have made “passability in a long film” and “heat setting treatment in post-processing high temperature. It was speculated that the “passability” would worsen. Therefore, the present inventors can improve the “passability in a long film” and the “passability when a heat setting process in post-processing is performed at a high temperature” by smoothing “circulation of hot air”. I thought that. And as a result of trial and error in order to grasp the relationship between the temperature air volume condition of the heat setting device, the covering mode of the shielding plate, and the film permeability in the post-processing, the following (1) By taking measures, there was a tendency that “passability in a long film” and “passability when heat-setting treatment in post-processing was performed at a high temperature” were improved. And based on the knowledge, as a result of further trial and error, the present inventors have taken the following means (1) and then taken the following means (2) and (3). The inventors have found that it is possible to obtain a film roll having good permeability, and have come up with the present invention.
(1) Adjustment of temperature and air volume of plenum duct in heat fixing device (2) Adjustment of shut-off condition of hot air outlet of plenum duct in heat fixing device (3) Heat cutoff between stretching zone and heat fixing device Each of the above-described means will be described sequentially.

(1) Adjusting the temperature and air volume of the plenum duct in the heat setting device In order to heat and cool the heat setting process step by step, the heat setting device is generally divided into several sections (heat setting zones) with different temperatures. I know. In the production of the film roll of the present invention, each plenum duct is designed such that the product of the temperature difference and the wind speed difference between adjacent heat setting zones of the heat setting device is 250 ° C. · m / s or less. It is indispensable to adjust the temperature and air volume of the hot air blown out from. For example, when the heat setting device is divided into first to third heat setting zones, the product of the temperature difference and the wind speed difference between the first zone and the second zone, and between the second zone and the third zone. Both products of the temperature difference and the wind speed difference are adjusted to be 250 ° C. · m / s or less. Thus, by adjusting the temperature and air volume of hot air, “circulation of hot air” becomes smooth. When combined with a method of attaching a discontinuous shielding plate, which will be described later, to the hot air outlet, the “temperature hunting phenomenon” is effectively suppressed. Thus, for the first time, it is possible to obtain a long film having good passability when the heat setting treatment in the post-processing is performed at a high temperature.

  If the product of the temperature difference and the wind speed difference between adjacent heat setting zones is 250 ° C. · m / s or less (for example, the temperature difference between adjacent heat setting zones is set to 20 ° C. The temperature difference between adjacent heat setting zones is set to 10 m / s), “circulation of hot air” in the heat setting device is smoothly performed, and “temperature hunting phenomenon” is effectively suppressed. This is preferable. In addition, if the product of the temperature difference and the wind speed difference between adjacent heat setting zones is 250 ° C. · m / s or less, the heat setting zone downstream from the heat setting zone upstream as an accompanying flow caused by the passage of the film The temperature difference of the air flowing into Therefore, it is preferable because the temperature in the width direction of the downstream heat setting zone is stabilized. The product of the temperature difference and the wind speed difference is preferably 200 ° C. · m / s or less, and more preferably 150 ° C. · m / s or less. Further, as in Patent Document 2, if the air volume of each plenum duct is made constant and the wind speed of each plenum duct is made different, a “temperature hunting phenomenon” occurs. In the present invention, the “temperature hunting phenomenon” is effectively suppressed by making the wind speed in each zone constant.

(2) Adjustment of Plenum Duct Cut-off Conditions in Heat Fixing Device In the production of the film roll of the present invention, individual plenum ducts are not attached as shown in FIG. It is necessary to attach the rod-shaped shielding plates S, S,... So as to shield the hot air outlets (nozzles) 2, 3,. By using such a discontinuous shielding plate, “circulation of hot air” is performed smoothly. Moreover, it is preferable not to attach the same length of the shielding plate to each plenum duct, but to gradually increase the length of the shielding plate from the inlet of the heat fixing device to the outlet (film passing direction) (see FIG. 1). . Thus, by adjusting the length, the temperature of the hot air exposed to the film edge is adjusted, and the elimination of distortion at the film edge is promoted. The material of the shielding plate may be any material as long as it can withstand the temperature of the heat fixing device and does not stain the film or adhere the film, but it is the same material as the plenum duct from the viewpoint of thermal expansion. Is preferably used. Moreover, in order to suppress the thermal contraction rate difference at the film edge by the shielding plate to the extent of the present invention, the number of shielding plates is preferably set in consideration of the temperature difference between the central portion and the end portion.

(3) Blocking of heating between the stretching zone and the heat setting device (installation of an intermediate zone)
The biaxially stretched polyethylene terephthalate resin film roll is usually heat-set after being longitudinally and laterally stretched. In the production of the film roll of the present invention, it is desirable to install an intermediate zone in which active hot air is not blown between the zone that is longitudinally and transversely stretched and the heat setting device that is heat set. As a result, the heat is completely shut off between the stretching zone and the heat setting device. More specifically, when a strip-shaped paper piece is hung between the stretching zone and the heat setting device in the state where the drawing zone and the heat setting device are in the same condition as in film production, the paper piece is almost completely removed. It is preferable to block the hot air from the stretching zone and the heat fixing device so as to hang down in the vertical direction. Note that such an intermediate zone may be surrounded by a housing, or may be provided so that a continuously manufactured film is exposed. When the hot air is sufficiently blocked in the intermediate zone, the shielding effect of the shielding plate in the heat fixing device is exhibited, and good film passage during post-processing can be obtained.

  As described above, by adopting the above methods (1) to (3), the “hot air circulation” in the heat fixing device can be smoothly executed, and the “temperature hunting phenomenon” can be suppressed. As a result, it is possible to sufficiently promote relaxation in the longitudinal direction at the edge of the width direction, such as “passability in a long film” and “passability when heat setting treatment in post-processing is performed at a high temperature”. Can be improved. In the above description, the method of suppressing the “temperature hunting phenomenon” by smoothly executing “circulation of hot air” in the heat fixing device in which the plenum duct is installed. The above description discloses the technical idea of how the film roll of the present invention can be obtained by applying thermal energy to the film at the production level. It can be easily carried out by a method different from the above-described method, and the film roll of the present invention can be obtained by a different method. In other words, even with another type of heat fixing device, the "circulation of hot air" is smoothly executed to suppress the "temperature hunting phenomenon" and then sufficiently relaxed in the longitudinal direction at the edge of the width direction. Improve "passability in long film" and "passability when heat-setting treatment in post-processing is performed at a high temperature" like the film roll of the present invention by applying sufficient heat energy to the film It is possible to obtain a finished film roll.

  However, even in the above heat fixing method, the film in the vicinity of the clip is restricted in movement by the clip, so that the relaxation in the longitudinal direction is not sufficiently performed, and the thermal contraction rate is sufficient at the film edge. It may not be improved. Even when trying to reduce the heat shrinkage in the longitudinal direction, simply increasing the temperature at heat setting may cause problems such as coloration of the film or crystallization progressing to whiten the film, resulting in deterioration of transparency. It was difficult to reduce the rate.

  Therefore, in the present invention, in addition to the above-described heat setting treatment method, the thermal contraction rate of the film edge portion can be suppressed by taking the following means (1) to (3). That is, (1) cutting and removing the film edge held by the clip, (2) reducing the film take-off speed, and relaxing the entire film width removed from the clip in the longitudinal direction, (3) The film having the full width subjected to the relaxation treatment is again gripped with a clip, and the film is cooled to room temperature while maintaining the flatness. Hereinafter, each of the above-described means will be described sequentially.

  (1) First, the film edge held by the clip is cut and removed. Since the film portion held by the clip is not uniformly stretched in the transverse stretching, the thickness is usually thicker than other regions of the film. When there are regions having different thicknesses as described above, the entire film width cannot be relaxed uniformly in the step (2). Therefore, prior to the longitudinal relaxation treatment, the film edge portions having different thicknesses (the vicinity being held by the clip for lateral stretching) are cut and removed. The film edge is cut by setting a cutting blade in the vicinity where the edge is released from the clip so that the influence of gripping the clip does not reach the center. The phenomenon that the film plane undulates due to the cutting of the film, but in order to suppress such undesired fluttering, it is desirable to provide the cutting blade in a place where the wind from the air duct installed in the tenter does not hit. The edge portion of the film that has been cut and removed is recovered, but it is preferable to cut the film just before the film leaves the clip so that the change in tension accompanying the cutting and recovery does not reach the film body. Also, for collecting the film edge, it is preferable to use a grooved metal roll and insert a blade between the grooves to nip the film where there is no groove. Further, in order to perform uniform relaxation in the longitudinal direction, the thickness of the film cut surface is preferably the thickness of the central portion in the width direction, that is, ± 10% or less of the average value of the product thickness. Preferably it is ± 8% or less, particularly preferably ± 4% or less.

  (2) Next, by reducing the take-up speed of the film, the entire width of the film removed from the clip is relaxed in the longitudinal direction. After removing the film edge, the film is again held by the clip by the clip chain installed in the next step (cooling zone). Here, by setting the progress speed of the clip chain (second clip chain) in the cooling zone to be slower than the progress speed of the clip chain (first clip chain) until the heat setting process, the film take-up speed is attenuated. Until the film edge is gripped again in the next step, the longitudinal relaxation is performed over the entire width of the film. The relaxation rate is adjusted by the take-up speed. The relaxation rate in the present invention is preferably 1% or more and 6% or less. If it is less than 1%, the effect is small, and if it exceeds 6%, the flatness of the film is deteriorated. Furthermore, it is preferable that the temperature of the relaxation zone is controlled by hot air whose temperature is adjusted. In the system according to the present invention, the system disclosed in Japanese Patent Publication No. 2-0221818 (Patent Document 4), that is, by providing a bendable structure between adjacent clips, the vertical clip interval is adjusted, and the vertical direction As compared with the method of achieving the relaxation, a larger relaxation rate can be obtained. In the method described in Patent Document 4, it is difficult to suppress the fluctuation of the relaxation rate due to mechanical operation, and the same degree as the slit relaxation method of the present invention unless the relaxation rate is 2.0% or less. The effect cannot be obtained. Therefore, in the method according to the present invention, effective relaxation processing can be performed even with a lower relaxation rate.

  (3) Finally, the film having the full width subjected to the relaxation treatment is again gripped with a clip and cooled to room temperature while maintaining the flatness. Since the film relaxed in the longitudinal direction is still at a high temperature of 170 to 120 ° C., the film is likely to be deformed by disturbance in the state as it is, and when the temperature is lowered in the deformed state, the deformation is fixed and the flatness is improved. Collapse. Therefore, in order to maintain flatness, cooling is performed with the film edge held by a clip. The film is cooled to room temperature such that it is below the glass transition temperature (Tg). After the film has cooled, the film edge is released from the clip and led to a conventional winding process.

  As described above, by adopting the above-described method, it is possible to reduce the contraction rate HS150 in the longitudinal direction to −0.25% or more and 0.25% or less without deteriorating the flatness. . In addition, when an additional relaxation treatment is performed in a later step, surface defects such as roll scratches are likely to occur on the film surface. In the present invention, by performing the relaxation treatment in the longitudinal direction in the in-line process as described above, the surface defects of the film can be reduced and the productivity is also advantageous. Furthermore, when HS180 is made less than 1.15%, there is an advantage that the mechanical accuracy is higher than that of the conventional method (Patent Document 4), and the method can be carried out stably.

  Hereinafter, the present invention will be described in detail by way of examples. However, the present invention is not limited to the embodiments of the examples, and can be appropriately changed without departing from the spirit of the present invention. . In addition, the evaluation method of a film characteristic is as follows.

[Δn _ab ]
The sample film was cut out from the edge part (area | region within 50 mm from an edge) of a film roll. Each cut out sample film was allowed to stand for 2 hours or more in an atmosphere of 23 ° C. and 65% RH. For each sample sample, using an “Abbe refractometer 4T type” manufactured by Atago Co., Ltd., the refractive index (na) in _a direction that forms an angle of 45 degrees with the film winding direction, and the film winding direction with 135 degrees The refractive index (n _b ) in the direction forming the angle (that is, the direction forming the angle of 45 degrees and the direction forming the angle of 90 degrees) was measured. The absolute value of the difference between these two refractive indexes was Δn _ab, and Δn _ab = | Δn _a −Δn _b | Δn _ab was measured for both edge portions of the film roll, and the larger one was taken as Δn _ab of the present invention.

[Heat shrinkage of film]
The first sample cut-out part is provided within 2 m from the end of film winding, and the sample cut-out part is provided for each length obtained by dividing the film winding length into nine equal parts from the end of film winding, and within 2 m from the beginning of film winding. By providing the final cutout portion, a total of 10 sample cutout portions were provided for one slit roll. The sample film was cut out from the 10 sample cut-out portions. For each cut-out part, a sample film having a width of 20 mm and a length of 250 mm is cut out along the film winding direction from the left and right edge parts (the part within 50 mm from the edge) of the film roll, and the left edge part and the right edge part Ten sample films were obtained for each part. Each sample film was marked at intervals of 200 mm, placed in a heating oven adjusted to 150 ° C., and the amount of heat shrinkage HS 150 at 150 ° C. was measured according to JIS C-2318. Furthermore, it put into the heating oven adjusted to 180 degreeC, and heat shrinkage HS180 in 180 degreeC was measured like the above. In the table, “thermal contraction rate at each cutout portion” indicates a combination of the thermal contraction rate difference between the minimum and the maximum in the width direction.

[Passability of film]
The flatness of the film after the heat treatment was evaluated by the following method. As a heat treatment step, a coater having a distance between two rolls of 1,900 mm was used, the temperature was set to 100 ° C. or 160 ° C., and the furnace tension was set to 100N. Next, two rolls are horizontally arranged so that the roll interval is 2,000 mm, and further, the iron bar is positioned at the center position of the two rolls at a position 30 mm below the common tangent of the roll upper surface. Arranged. The film passed through the heat treatment step was passed between two rolls under a tension of 98N. When the film was allowed to pass through, it was marked as ◯ when the film was not in contact with the iron bar, and x when it was in contact with the iron bar. These steps were performed continuously, and it was visually confirmed whether or not the film contacted the iron bar.

  In addition, Table 1 shows the film forming conditions of the film rolls in Examples and Comparative Examples.

[Example 1]
After drying polyethylene terephthalate containing 0.03% by mass of silica particles (manufactured by Fuji Silysia Chemical Ltd., Silicia 310) as an additive ([η] = 0.60) to a moisture content of 50 ppm, extrusion is performed. The resin was charged in a hopper directly above the machine and melted at a temperature of 285 ° C. in an extruder, and the melted resin was filtered with a filter material of stainless sintered body (nominal filtration accuracy: 90% of particles having a size of 10 μm or more). Next, the resin sheet was extruded from a T-shaped die, and was wound around a casting drum whose surface was adjusted to 30 ° C. using an electrostatic application casting method, and cooled and solidified to obtain an unstretched sheet of 1,340 μm.

  And the obtained unstretched sheet is heated to 100 ° C. by a heated roll group and a near-infrared heater, and then continuously 3.5 times in the longitudinal direction in a roll group having a peripheral speed difference. The stretching operation was performed, and then the end of the uniaxially stretched film was held with a clip and guided to a hot air zone heated at 130 ° C., and the stretching operation was continuously performed 4.0 times in the width direction. Furthermore, after heat-setting at 238 ° C. by the method described later, 1.7% lateral relaxation treatment was performed at 225 ° C. Further, after passing through a heat setting zone at 170 ° C., when exiting the heat setting zone, a region 150 mm from the film end was cut off at both ends of the film held by the clip. The edge of the cut film edge was collected by inserting a blade into the groove of a grooved metal roll and niping the non-grooved part to minimize the waviness of the film surface by cutting the edge. .

The film with the edge cut away was passed through a 170 ° C. thermal relaxation zone without holding the edge with a clip and then led to the cooling zone with a second clip chain. The longitudinal relaxation treatment was performed in the thermal relaxation zone by reducing the speed of the second clip chain by 2.5% from the speed of the first clip chain. Thereafter, the film edge was held with a clip, and the film temperature was lowered to a room temperature below the glass transition temperature through the cooling zone while maintaining flatness. By winding this film in a roll shape, a biaxially oriented polyester film roll (mill roll) in which a film having a thickness of 100 μm and a width of 3,300 mm was wound up by 3,500 m was produced. While rewinding the mill roll, both ends are removed by 150 mm each, and the remaining part is slit at three equal intervals in the width direction, and by removing approximately 200 m from the surface layer (winding end portion) of the mill roll, Three slit rolls having a width of 1,000 mm and a winding length of 3,010 m were obtained. Of the three slit rolls obtained as described above, using the slit roll corresponding to one end side of the mill roll (the right side when viewed downstream from the upstream of the film flow), the characteristics of the film and the film roll Evaluation was performed. The evaluation results are shown in Table 4. The larger Δn _ab of this roll was 0.042 as shown in Table 4, while the smaller Δn _ab of the other end was 0.017.

[Heat setting]
The said heat setting process was performed with the heat setting apparatus which has a structure shown in FIG. The heat setting device is divided into four heat setting zones called first to fourth zones. Eight plenum ducts a to x are provided in the first to third zones, respectively. Eight plenum ducts are also provided in the fourth zone. Each plenum duct is vertically installed at 400 mm intervals with respect to the film traveling direction so as to be perpendicular to the film traveling direction. Then, hot air is blown from the hot air outlet (nozzle) of the plenum duct to the stretched film.

  In Example 1, discontinuous rod-shaped shielding plates S, S,... Were attached to the hot air outlets of 15 plenum ducts a to o in the manner shown in FIG. FIG. 4 shows a state where the heat fixing device having the shielding plates S, S... Attached to the hot air outlets of the plenum ducts a to o is viewed from above. The longitudinal center of each of the attached shielding plates S, S... Is set so as to substantially coincide with the center of the width of the film passing through the heat fixing device. In addition, the length of each shielding plate S, S... (The dimension in the width direction of the film to be manufactured) is set so that it gradually becomes wider from the inlet to the outlet of the heat fixing device (that is, it becomes wider at the end). did. Table 2 shows the shielding ratio of the hot air outlets of each of the plenum ducts a to o (the shielded area of the hot air outlet by the shielding plate / the area of the hot air outlet). In addition, let the shielding aspect by the shielding board in Example 1 be "A aspect."

  Table 3 shows the temperatures and wind speeds of the first to fourth zones of the heat setting device in Example 1. In addition, as for the temperature conditions of the 1st-4th zone of the heat setting apparatus of Example 1, and the wind speed conditions, the product of the temperature difference between adjacent heat setting zones and a wind speed difference is 250 degrees C * m / s or less. Set to. In addition, let the temperature of 1st-4th zone in Example 1, and wind speed conditions be "I" conditions.

[Example 2]
Adjusting the take-up speed of the unstretched sheet to change the thickness of the unstretched sheet to 2,380 μm, and as a method for cooling and solidifying the unstretched sheet, a cooling air of 16 ° C. is used together with a casting drum having a surface temperature of 30 ° C. In addition to spraying, the mill roll was wound up 2,500 m of a film having a thickness of 188 μm and a width of 3,300 mm in the same manner as in Example 1 except that the draw ratio in the longitudinal direction was changed to 3.3 times. Got. While rewinding the mill roll, the both ends were removed by 150 mm, and the remaining part was slit into three at equal intervals in the width direction. By removing approximately 200 m from the surface layer of the mill roll, width 1 Three slit rolls having a winding length of 2,010 m at 2,000 mm were obtained. Of the three slit rolls, the characteristics of the film and the film roll are evaluated using the slit roll corresponding to one edge side of the mill roll (the right side when viewed from the upstream to the downstream of the film flow). It was. The evaluation results are shown in Table 4.
The larger Δn _ab of this roll was 0.037 as shown in Table 4, while the smaller Δn _ab of the other end was 0.016.

[Example 3]
Except for changing the extrusion amount of the extruder to increase the width of the unstretched sheet and changing the temperature and wind speed of the first to fourth zones of the heat setting device as shown in Table 3, the same as in Example 1. Thus, a mill roll was obtained in which a film having a thickness of 100 μm and a width of 5,200 mm was wound up by 3,500 m. While rewinding the mill roll, remove both ends by 100 mm and repeat the process of slitting the remaining part into five at equal intervals in the width direction. By removing about 200 m from the surface of the mill roll, the width is 1,000 mm. Five slit rolls having a winding length of 3,010 m were obtained. Of the five slit rolls obtained as described above, a film and a film roll using a slit roll corresponding to one edge side of the mill roll (the right side when viewed downstream from the upstream of the film flow) Evaluation of characteristics was performed. The evaluation results are shown in Table 4. In addition, let the shielding aspect by the shielding board in Example 3 be a "B aspect", and let the temperature and wind speed conditions of the 1st-4th zone in Example 3 be "II conditions."
The larger Δn _ab of this roll was 0.042 as shown in Table 4, while the smaller Δn _ab of the other end was 0.030.

[Example 4]
Adjusting the take-up speed of the unstretched sheet to change the thickness of the unstretched sheet to 2,380 μm, and as a method for cooling and solidifying the unstretched sheet, a cooling air of 16 ° C. is used together with a casting drum having a surface temperature of 30 ° C. In addition to changing the draw ratio in the longitudinal direction to 3.3 times, and changing the temperature and wind speed of the first to fourth zones of the heat setting device as shown in Table 3, Similarly, a mill roll was obtained in which a film having a thickness of 188 μm and a width of 5,200 mm was wound up by 2,500 m. While rewinding the mill roll, remove both ends by 100 mm and repeat the process of slitting the remaining part into five at equal intervals in the width direction. By removing about 200 m from the surface of the mill roll, the width is 1,000 mm. Five slit rolls having a winding length of 2,010 m were obtained. And the characteristic of a film and a film roll was evaluated using the slit roll in the same position as Example 3. The evaluation results are shown in Table 4.
The larger Δn _ab of this roll was 0.037 as shown in Table 4, while the smaller Δn _ab of the other end was 0.023.

[Example 5]
The thickness of the unstretched sheet was increased to 1,680 μm, and the heat setting conditions were changed as shown in Table 3, except that the melt extrusion amount by the extruder was increased, and the thickness was 125 μm and the width was 5,200 mm. The mill roll which wound up 6,500m of this film was obtained. After that, while rolling the mill roll, the process of slitting the remaining portions into five at equal intervals in the width direction while removing both ends by 100 mm is repeated, and by removing approximately 200 m from the surface layer of the mill roll, the width 1 Ten slit rolls having a winding length of 3,010 m at 1,000 mm were obtained. Of the 10 slit rolls obtained as described above, a film and a film roll using a slit roll corresponding to one edge side of the mill roll (the right side when viewed from the upstream side of the film flow) Evaluation of characteristics was performed. The evaluation results are shown in Table 4.
The larger Δn _ab of this roll was 0.054 as shown in Table 4, while the smaller Δn _ab of the other end was 0.034.

[Example 6]
Using the roll from the center of the mill roll of the slit roll evaluated in Example 5 from the mill roll obtained in the same manner as in Example 5, the characteristics of the film and the film roll were evaluated. The evaluation results are shown in Table 4.
The larger Δn _ab of this roll was 0.032 as shown in Table 4, while the smaller Δn _ab of the other end was 0.017.

[Example 7]
Using the slit roll obtained in the same manner as in Example 3 except that the speed of the take-up machine was decreased to increase the thickness of the unstretched sheet to 1,340 μm and the longitudinal relaxation amount was changed to 2.7%. The properties of the film and film roll were evaluated. The evaluation results are shown in Table 4.
The larger Δn _ab of this roll was 0.038 as shown in Table 4, while the smaller Δn _ab of the other end was 0.024.

[Comparative Example 1]
As in Example 1, except that heat fixing was performed without attaching a shielding plate to the hot air outlet of each plenum duct, and the temperatures and wind speeds of the first to fourth zones of the heat fixing device were changed as shown in Table 3. did. And the characteristics of a film and a film roll were evaluated using the slit roll of the same position as Example 1. The evaluation results are shown in Table 4. In addition, let the temperature of the 1st-4th zone in Example 1, and a wind speed condition be "VIII" conditions.
The larger Δn _ab of this roll was 0.042 as shown in Table 4, while the smaller Δn _ab of the other end was 0.017.

[Comparative Example 2]
As in Example 2, except that heat fixing was performed without attaching a shielding plate to the hot air outlet of each plenum duct, and the temperatures and wind speeds of the first to fourth zones of the heat fixing device were changed as shown in Table 3. did. And the characteristics of a film and a film roll were evaluated using the slit roll of the same position as Example 2. FIG. The evaluation results are shown in Table 4.
The larger Δn _ab of this roll was 0.037 as shown in Table 4, while the smaller Δn _ab of the other end was 0.016.

[Comparative Example 3]
The same procedure as in Example 1 was performed except that the longitudinal relaxation treatment was not performed. And the characteristics of a film and a film roll were evaluated using the slit roll of the same position as Example 1. The evaluation results are shown in Table 4.
The larger Δn _ab of this roll was 0.041 as shown in Table 4, while the smaller Δn _ab of the other end was 0.016.

[Comparative Example 4]
The same operation as in Example 2 was performed except that the longitudinal relaxation treatment was not performed. And the characteristics of a film and a film roll were evaluated using the slit roll of the same position as Example 2. FIG. The evaluation results are shown in Table 4.
The larger Δn _ab of this roll was 0.036 as shown in Table 4, while the smaller Δn _ab of the other end was 0.016.

[Comparative Example 5]
As a relaxation treatment in the vertical direction, the adjacent clips are connected with a flexible chain link that is connected to the bearing. By moving the bearing along the guide rail, the bending angle of the chain link is displaced, and the clip interval in the longitudinal direction is increased. The same procedure as in Example 1 was performed except that a longitudinal relaxation treatment of 2.5% was performed by narrowing. And the characteristics of a film and a film roll were evaluated using the slit roll of the same position as Example 1. The evaluation results are shown in Table 4.
The larger Δn _ab of this roll was 0.042 as shown in Table 4, while the smaller Δn _ab of the other end was 0.017.

[Comparative Reference Example 1]
Reduce the speed of the take-up machine to increase the thickness of the unstretched sheet to 1,380 μm, and attach an integrated large shielding plate to the hot air outlet of each plenum duct of a to o of the heat fixing device. Six slit rolls were obtained in the same manner as in Example 1 except that the relaxation was not performed. The shape of the shielding plate was adjusted so that the shielding rate by the large shielding plate was the same as in Example 1. And the characteristic of a film and a film roll was evaluated using the slit roll in the same position as Example 1. The evaluation results are shown in Table 4.
The larger Δn _ab of this roll was 0.042 as shown in Table 4, while the smaller Δn _ab of the other end was 0.017.

[Comparative Reference Example 2]
The same unstretched sheet as in Comparative Reference Example 1 was used, and the plenum ducts of the transverse stretching machine to be used were five and changed as shown in Tables 1, 2, and 3. Unlike Examples 1 to 7, Comparative Examples 1 to 4, and Comparative Reference Example 1, the air volume of the plenum duct was made constant, and the wind speed was different for each of the five windshields. The evaluation results are shown in Table 4.
The larger Δn _ab of this roll was 0.040 as shown in Table 4, while the smaller Δn _ab of the other end was 0.016.

[Effects of Example Film]
From Table 4, the film rolls of the examples all have a difference in heat shrinkage rate across the entire width of the roll (ie, heat shrinkage rate difference) as small as 0.25% or less in absolute value, and heat shrinkage rate in the longitudinal direction. The amount of fluctuation is small, and the passability during post-processing is good. It can also be seen that the heat shrinkage amount in the longitudinal direction is small and suitable even when processing with a single wafer is performed without passing through heat. On the other hand, the film roll of the comparative example has a small difference in heat shrinkage rate over the entire width of the roll, but the amount of heat shrinkage in the longitudinal direction is large when processing on a single wafer is performed, and it is separately used for use. An annealing treatment is necessary.

  Since the polyethylene terephthalate resin film roll of the present invention has excellent processing characteristics as described above, heat treatment in various optical films and other post-processing is relatively long in a high temperature zone (about 160 ° C.). It can be suitably used as a film for processing performed over a period of time (10 to 60 seconds), and can also be suitably used for high-temperature processing on a single wafer in applications where heat treatment is not allowed to pass through.

Explanatory drawing which shows the shielding aspect by the conventional shielding board (a is a partial cross section of the heat fixing device, and b is the state where the shielding board is attached to the hot air outlet of the plenum duct from above. It shows what you saw). BRIEF DESCRIPTION OF THE DRAWINGS It is explanatory drawing which shows the shielding aspect by the shielding board in this invention (a is a partial vertical cross section of a heat fixing apparatus, b is the state which attached the shielding board to the hot-air blowing outlet of the plenum duct. Is a view from above.) It is explanatory drawing which shows the state which saw through the heat fixing apparatus used by the Example and the comparative example from the top. It is explanatory drawing which shows the shielding aspect by the shielding board in Example 1. FIG. It is a top view which shows a relaxation process zone and a cooling zone from the heat setting zone which implements relaxation of the longitudinal direction in this invention. It is an enlarged view of the edge part vicinity of the top view which shows a relaxation process zone and a cooling zone from the heat setting zone which implements relaxation of the longitudinal direction in this invention. It is a side view which shows the cutting condition of the film edge part made when implementing relaxation of the longitudinal direction in this invention.

Explanation of symbols

1: heat fixing device 2: hot air outlet 3, a to x: plenum duct 4: traveling rail of first clip chain 5: traveling rail of second clip chain F: film S: shielding plate A: winding of film Taking direction Z1: First zone Z2: Second zone Z3: Third zone Z4: Fourth zone N1, N2, N3: Intermediate zone HS: Heat fixing zone R: Relaxation zone C: Cooling zone R1: Grooved roll R2: Nip roll CU: Blade F1: Trimmed film edge

Claims (7)

A biaxially stretched polyethylene terephthalate resin film slit to have a length of 300 m or more and 8,000 m or less and a width of 0.7 m or more and 2.2 m or less. Biaxially stretched polyethylene terephthalate resin film in which Δn _ab is 0.015 or more and 0.060 or less, which is the difference between the refractive index in the direction that forms an angle and the refractive index in the direction that forms an angle of 135 degrees with the winding direction of the film A roll,
The first sample cutout is provided within 2 m from the end of winding of the film, the final cutout is provided within 2 m from the start of winding of the film, and the length between the first and final cutout is divided into nine equal parts. A biaxially stretched polyethylene terephthalate resin film roll that satisfies the following requirements (1) and (2) when a total of 10 sample cutout portions are provided by providing sample cutout portions in
(1) When each sample is cut out from a position within 50 mm from one end edge and a position within 50 mm from the other end edge in the roll width direction, and the two samples are heated at 180 ° C. for 30 minutes. HS180, which is the heat shrinkage rate in the film winding direction, was obtained, and when the heat shrinkage difference, which is the difference between the HS180, was obtained, the heat shrinkage difference in all cutout portions was 0.1% or less. (2) In each of the cutout portions, when a sample is cut out from a position within 50 mm from one end edge and a position within 50 mm from the other end edge in the width direction of the roll, and HS180 is obtained for each sample, HS180 of samples at both ends at all cutouts is 0.4% or more and less than 1.15%. The biaxially stretched polyethylene terephthalate resin film roll according to claim 1, wherein the wound biaxially stretched polyethylene terephthalate resin film has a thickness of 70 µm or more and 400 µm or less. A production method for producing a biaxially stretched polyethylene terephthalate-based resin film roll according to claim 1 or 2, wherein a film forming step forms an unstretched sheet by melting and extruding a raw material resin from an extruder; , A biaxial stretching process in which the unstretched sheet obtained in the film forming process is biaxially stretched in the machine direction and the transverse direction, a heat setting process in which the film after biaxial stretching is heat-set, and the film after heat setting in the longitudinal direction A process of relaxing treatment in the direction, and the heat setting step is performed in a heat setting apparatus that satisfies the following requirements (3) to (6): Production of a biaxially stretched polyethylene terephthalate resin film roll Method.
(3) A plurality of wide plenum ducts for blowing out hot air are arranged vertically opposite to the film traveling direction. (4) Shielding for shielding hot air outlets from the plurality of plenum ducts. (5) The dimension of each shielding plate in the traveling direction of the film is adjusted to be substantially the same as the dimension of the outlet of each plenum duct in the traveling direction of the film. The dimension in the width direction of the film is adjusted so as to become gradually longer with respect to the traveling direction of the film. (6) The air speed of the plenum duct in each heat setting zone is made constant.   In the step of carrying out the relaxation treatment in the longitudinal direction according to claim 3, performing the relaxation treatment in the longitudinal direction by cutting and separating the film edge and then reducing the take-up speed of the film cut and separated from the edge. A method for producing a biaxially stretched polyethylene terephthalate resin film roll.   In the biaxial stretching process, the film is stretched in the transverse direction after stretching the film in the longitudinal direction, and an intermediate zone that does not perform wind blowing is provided between the zone that performs the transverse stretching and the heat setting device. The method for producing a biaxially stretched polyethylene terephthalate resin film roll according to claim 3 or 4.   The heat setting device is divided into a plurality of heat setting zones, and the product of the temperature difference and the wind speed difference between adjacent heat setting zones is set to be 250 ° C. · m / s or less. The manufacturing method of the biaxially-stretched polyethylene terephthalate-type resin film roll of Claims 3-5 characterized by the above-mentioned.   The method for producing a biaxially stretched polyethylene terephthalate-based resin film roll according to claim 3, wherein after the longitudinal relaxation treatment, the film is subjected to a cooling treatment while holding the film edge.

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