JP5167700B2 - Polyester resin film roll and method for producing the same - Google Patents

Description

  The present invention relates to a polyester-based resin film roll made of a polyester-based resin having a copolyester as a constituent component, and more particularly to a polyester-based resin film roll having excellent processing characteristics.

  Conventionally, as a sheet | seat for shaping | molding, a polyvinyl chloride film is typical and has been preferably used at points, such as workability. On the other hand, the film has problems such as generation of toxic gas when the film burns due to fire and the like, bleed-out of the plasticizer, and the recent demand for environmental resistance has demanded new materials with low environmental impact. ing.

In order to satisfy the above requirements, unstretched sheets made of polyester, polycarbonate and acrylic resin have been used in a wide range of fields as non-chlorine materials. In particular, an unstretched sheet made of a polyester-based resin has attracted attention because it has good mechanical properties and transparency and is excellent in economic efficiency. For example, an unstretched polyester-based sheet comprising substantially non-crystalline polyester-based resin in which about 30 mol% of ethylene glycol component in polyethylene terephthalate is substituted with 1,4-cyclohexanedimethanol is disclosed ( For example, see Patent Documents 1 to 5).
Japanese Patent Laid-Open No. 9-156267 JP 2001-71669 A JP 2001-80251 A JP 2001-129951 A JP 2002-249652 A

  The above-mentioned unstretched polyester sheet satisfies market demands regarding moldability and laminate suitability, but because it is an unstretched sheet, it does not have sufficient heat resistance and solvent resistance and satisfies high market demands. It has not yet reached.

As a method for solving the above problems, a method using a biaxially stretched polyethylene terephthalate film is disclosed (for example, see Patent Documents 6 to 9).
JP-A-9-187903 JP-A-10-296937 Japanese Patent Laid-Open No. 11-10816 JP-A-11-268215

  However, although the heat resistance and solvent resistance are improved, the above method has insufficient moldability and does not satisfy the market demand in terms of the balance of overall quality.

As a method for solving the above problems, the following methods are disclosed (for example, see Patent Documents 10 and 11). These films are a moldable polyester film having a balance of moldability, heat resistance, and chemical resistance. Useful as.
JP-A-2-204020 JP 2001-347565 A

  However, the polyester-based resin films disclosed in Patent Documents 10 and 11 are stretched in the longitudinal direction between rolls having a difference in rotational speed, and then in the width direction in a state where the end of the film is gripped in the tenter. It is manufactured by drawing and heat setting in a tenter. 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. When such a distorted slit roll is used for post-processing with heat treatment such as molding, offset printing, vapor deposition, primer processing, prism lens processing, hard coat processing, anti-glare (AR) processing, etc., a film As a result, the film is rubbed with the frame of the machine base or the like in the post-processing step, and the end portion is damaged. Moreover, it is very troublesome to adjust the post-processing conditions on the user side so that the film is not damaged. As such, the slit roll corresponding to the edge of the mill roll was difficult to use for the above-mentioned application, and therefore, when no additional treatment was performed, only the slit roll other than the edge of the mill roll could be used. .

  In addition, there is an increasing demand for wide slit rolls in order to reduce post-processing costs, but in order to collect such wide slit rolls with a high yield from the limited mill roll width, the narrow width is required as in the past. It is better to collect from a wider mill roll than from a mill roll. 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 keep the temperature uniformity in the width direction of the heat fixing device good. However, fine adjustment of the hot air blowing amount, etc. can improve the temperature uniformity in the width direction and reduce the difference in thermal shrinkage between the left and right to a certain extent. It is not possible to reduce the difference in thermal shrinkage between the left and right edges to a level sufficient to achieve the desired level.

  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 12). 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 A method of increasing the amount of hot air hitting the end by increasing the speed of the air blown from the plenum duct while keeping the amount of hot air blown to the outside (Patent Document 13) is disclosed.

JP 2001-138462 A JP 2002-79638 A

  However, the film at the end cannot be sufficiently relaxed by a method in which a continuous shielding plate is placed on the plenum duct (hot air blowing portion) in the heat setting process. Further, in the method of Patent Document 13, 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. Therefore, although the passability is improved to some extent when heat treatment in post-processing (coating and drying) is performed at a low temperature of about 120 ° C., the drying efficiency of the coating film (hard coat film, etc.) is increased or coated. For the purpose of increasing the strength of the film, the passability when heat treatment in post-processing is performed in a high temperature zone (about 160 ° C.) for a relatively long time (10 to 60 seconds) is not so much improved. Therefore, when post-processing is performed at a high temperature for a long time, the conditions must be adjusted in the post-processing, and there may be a situation where the conditions cannot be adjusted.

  In addition, in the method of simply covering the plenum duct with the heat-fixing process, the temperature hunting in the heat-fixing zone becomes large, so when manufacturing a long film (mill roll) of 1,000 m or more. 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.

  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 providing the polyester-type resin film roll with high. Another object of the present invention is to inexpensively and easily produce a polyester-based resin film roll comprising a copolyester having a very good film permeability in the heat treatment step during post-processing over the entire length of the roll. An object of the present invention is to provide a manufacturing method that can be used.

Among the present inventions, the structure of the invention described in claim 1 is a polyester 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. The difference between the refractive index in the direction that forms an angle of 45 degrees with the winding direction of the wound film and the refractive index in the direction that forms an angle of 135 degrees with the winding direction of the wound film. A certain Δn _ab is a polyester-based resin film roll having a value of 0.020 or more and 0.080 or less, wherein the film is made of a polyester-based resin having a melting point of 180 to 250 ° C. and having a copolymer polyester as a constituent component. The first sample cutout is provided within 2 m from the end, the final cutout is provided within 2 m from the start of film winding, and the first and last cutout The by providing a sample cutout portion for each length was 9 aliquoted, when provided with a total of 10 sample cutout portion, and satisfies the following requirements (1) to (3).
(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 film winding direction is obtained, and when the heat shrinkage rate difference which is the difference between the HS150 is obtained, the heat shrinkage rate difference in all cut-out portions is 0.7% 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 HS150 is obtained for each sample, HS150 of the samples at both end edges in all cutouts is 1.2% or more and 4.5% or less 3) The fluctuation amount of the HS 150 on the one end edge side in the width direction of the roll obtained in each cutout portion and the fluctuation amount of the HS150 on the other end edge side in the width direction of the roll obtained in each cutout portion are both 0. 4% or less

  The structure of the invention described in claim 2 is characterized in that, in the invention described in claim 1, the wound polyester resin film has a thickness of 10 μm or more and 400 μm or less.

The structure of the invention described in claim 3 is a manufacturing method for manufacturing the polyester-based resin film roll described in claim 1, wherein an unstretched sheet is obtained by melt-extruding a raw material resin from an extruder. A film forming step to be formed, a biaxial stretching step in which the unstretched sheet obtained in the film forming step is biaxially stretched in the machine direction and the transverse direction, and a heat setting step in which the film after biaxial stretching is heat-set. And the heat setting process is performed in the heat setting apparatus which satisfy | fills the following requirements (4)-(6), It is characterized by the above-mentioned.
(4) A plurality of wide plenum ducts for blowing out hot air are arranged vertically opposite to the traveling direction of the film. (5) Shielding for shielding hot air outlets from the plurality of plenum ducts. (6) 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 film traveling direction.

  The structure of the invention described in claim 4 is the invention described in claim 3, in which the biaxial stretching step stretches the film in the longitudinal direction and then stretches in the transverse direction, and performs the transverse stretching. An intermediate zone that does not perform wind blowing is provided between the zone and the heat fixing device.

  The structure of the invention described in claim 5 is the invention described in claim 3 or claim 4, wherein the heat setting device is divided into a plurality of heat setting zones and adjacent heat setting zones. The product of the temperature difference and the wind speed difference is set to be 250 ° C. · m / s or less.

  The polyester-based resin film roll of the present invention is capable of passing a film in a heat treatment process during post-processing such as offset lens processing, hard coat processing, AR processing, etc. when offset printing, vapor deposition processing, primer processing, etc. are performed as a roll. Therefore, post-processing can be performed with a very high yield. Therefore, the copolymerized polyester resin film roll of the present invention can be subjected to a heat treatment in a molding film, a printing film, an optical film, and other post-processing in a high temperature zone (about 160 ° C.) for a relatively long time (10 to 10). 60 seconds) can be suitably used as a processing film.

[Copolyester]
The polyester resin film roll of the present invention contains a copolymer polyester as a constituent component. Examples of the copolyester include (a) a copolyester composed of an aromatic dicarboxylic acid component, ethylene glycol, and a glycol component containing a branched aliphatic glycol or alicyclic glycol, or (b) terephthalic acid and isophthalic acid. A copolyester composed of an aromatic dicarboxylic acid component containing an acid and a glycol component containing ethylene glycol is preferred. Moreover, it is preferable from the point which improves the moldability that the polyester which comprises a biaxially-oriented polyester film contains a 1, 3- propanediol unit or a 1, 4- butanediol unit as a glycol component further. In the case of (a) above, the copolymerization polyester used in the present invention is preferably added with a copolymerization component so that the proportion of ethylene glycol in the total glycol component is 20 mol% to 95 mol%. The lower limit of the proportion of ethylene glycol in the total glycol component is preferably 30 mol%, more preferably 40 mol%, and the upper limit is preferably 90 mol%, more preferably 80 mol%, still more preferably. Is 70 mol%. In the case of the above (b), the copolymerized polyester used in the present invention is added with a copolymer component such that the proportion of terephthalic acid in the total aromatic dicarboxylic acid component is 50 mol% to 95 mol%. It is preferable. The lower limit of the proportion of terephthalic acid in the total aromatic dicarboxylic acid component is preferably 60 mol%, more preferably 70 mol%, and the upper limit is preferably 90 mol%.

  In the present invention, as the film raw material, any method of copolymerized polyester alone, one or more homopolyesters or a blend of copolymerized polyesters, or a combination of homopolyester and copolymerized polyester is possible. Among these, the blending method is preferable from the viewpoint of suppressing the lowering of the melting point.

  When using a copolymer polyester composed of an aromatic dicarboxylic acid component, ethylene glycol, and a glycol component containing a branched aliphatic glycol or alicyclic glycol as the copolymer polyester, the aromatic dicarboxylic acid component is Terephthalic acid, isophthalic acid, naphthalenedicarboxylic acid or ester-forming derivatives thereof are suitable, and the amount of terephthalic acid and / or naphthalenedicarboxylic acid component relative to the total dicarboxylic acid component is 70 mol% or more, preferably 85 mol% or more. Particularly preferred is 95 mol% or more, and particularly preferred is 100 mol%.

  Examples of branched aliphatic glycols include neopentyl glycol, 1,2-propanediol, 1,3-propanediol, 1,4-butanediol, and the like. Examples of the alicyclic glycol include 1,4-cyclohexanedimethanol and tricyclodecane dimethylol.

  Among these, neopentyl glycol and 1,4-cyclohexanedimethanol are particularly preferable. Furthermore, in the present invention, it is a more preferable embodiment that 1,3-propanediol or 1,4-butanediol is used as a copolymerization component in addition to the glycol component. Use of these glycols as a copolymerization component is suitable for imparting the above-mentioned properties, and is also excellent in transparency and heat resistance, and from the viewpoint of improving the adhesion with the adhesion modified layer. Is also preferable.

  When the copolymer polyester is composed of an aromatic dicarboxylic acid component containing terephthalic acid and isophthalic acid and a glycol component containing ethylene glycol, the amount of ethylene glycol is based on the total glycol component. It is 70 mol% or more, preferably 85 mol% or more, particularly preferably 95 mol% or more, and particularly preferably 100 mol%. As the glycol component other than ethylene glycol, the above-mentioned branched aliphatic glycol, alicyclic glycol, or diethylene glycol is preferable.

  Examples of the catalyst used for producing the copolymer polyester include alkaline earth metal compounds, manganese compounds, cobalt compounds, aluminum compounds, antimony compounds, titanium compounds, titanium / silicon composite oxides, and germanium compounds. . Of these, titanium compounds, antimony compounds, germanium compounds, and aluminum compounds are preferred from the viewpoint of catalytic activity.

  When producing the copolymer polyester, it is preferable to add a phosphorus compound as a heat stabilizer. As said phosphorus compound, phosphoric acid, phosphorous acid, etc. are preferable, for example.

  The copolyester preferably has an intrinsic viscosity of 0.50 dl / g or more, more preferably 0.55 dl / g or more, and particularly preferably from the viewpoint of moldability, adhesion, and film formation stability. 60 dl / g or more. If the intrinsic viscosity is less than 0.50 dl / g, the moldability tends to decrease. In addition, when a filter for removing foreign substances is provided in the melt line, the upper limit of the intrinsic viscosity is preferably 1.0 dl / g from the viewpoint of ejection stability during extrusion of the molten resin.

(Polyester resin used as film raw material)
In the present invention, one or more homopolyesters or copolymerized polyesters are used as film raw materials, and these are blended to form a film, thereby maintaining the same flexibility as when only the copolymerized polyester is used. However, transparency and high melting point (heat resistance) can be realized. In addition, when only a high melting point homopolyester (for example, polyethylene terephthalate) is used, it is possible to realize a melting point (heat resistance) having no flexibility and practical problem while maintaining high transparency.

  In addition, blending at least one or more of the above copolyester and a homopolyester other than polyethylene terephthalate (for example, polytetramethylene terephthalate or polybutylene terephthalate) and using it as a raw material for the polyester-based resin film roll of the present invention Further, it is further preferable from the viewpoint of moldability.

  In the present invention, the film raw material is a polyester resin obtained by blending a copolyester alone or one or more homopolyesters or copolyesters. The polyester resin used in the present invention preferably contains 5% to 50% of a copolymer component. The polyester resin used in the present invention contains a terephthalic acid component in an amount of 50 mol% to 95 mol% of the total aromatic dicarboxylic acid component, and / or an ethylene glycol component in an amount of 30 mol% to 95 mol% of the total diol component. Those that do are preferred. The lower limit of the terephthalic acid component is preferably 70 mol%, more preferably 80 mol%. Moreover, as a minimum of the said ethylene glycol component, 40 mol% is preferable and 50 mol% is more preferable.

  The melting point of the polyester resin is preferably 180 to 250 ° C. from the viewpoint of heat resistance and moldability. By controlling the type and composition of the polymer to be used and the film forming conditions within the range of the melting point, a balance between moldability and finish can be achieved, and a high-quality molded product can be produced economically. Here, the melting point is an endothermic peak temperature at the time of melting, which is detected at the time of primary temperature rise in so-called differential scanning calorimetry (DSC). The melting point was determined by measuring using a differential scanning calorimeter (manufactured by Mac Science, DSC3100S) at a heating rate of 20 ° C./min. The lower limit of the melting point is more preferably 190 ° C, further preferably 200 ° C, and particularly preferably 210 ° C or higher. If the melting point is less than 180 ° C, the heat resistance tends to deteriorate. Therefore, it may become a problem when exposed to high temperature during molding or use of a molded product.

  The upper limit of the melting point is preferably higher from the viewpoint of heat resistance, but when the polyethylene terephthalate unit is the main component, the film having a melting point exceeding 250 ° C. tends to deteriorate moldability. In addition, transparency tends to deteriorate. Furthermore, in order to obtain high moldability and transparency, it is preferable to control the upper limit of the melting point to 250 ° C.

  It is important that the polyester resin film of the present invention is a biaxially stretched film. In the present invention, solvent resistance and dimensional stability, which are disadvantages of an unstretched sheet, are improved by molecular orientation by biaxial stretching. That is, it is possible to improve the solvent resistance and heat resistance, which are disadvantages of the unstretched sheet, while maintaining good moldability of the unstretched sheet.

[Polyester resin film roll]
The polyester-based resin film roll of the present invention is a slit roll obtained by slitting a mill roll once manufactured to a predetermined number into a predetermined number, and Δnab (that is, a direction that forms an angle of 45 degrees with the winding direction of the wound film) And the difference (absolute value) between the refractive index of the film taken up and the refractive index in the direction forming an angle of 135 degrees with the winding direction of the film is limited to 0.020 or more and 0.080 or less. That is, the present invention is of the film roll, [Delta] n _ab is related to the slit rolls from end that is defined by the scope of 0.020 or more 0.080 or less. In the slit roll in which Δn _ab is less than 0.020, the above-mentioned problem of “strain (that is, physical property difference in the width direction)” does not occur. Moreover, in the slit roll distorted so that Δn _ab exceeds 0.080, 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.

  Moreover, the polyester-type resin film roll of this invention WHEREIN: When the sample cutout part is set by the method mentioned later, in each cutout part, the position within 50 mm from the one end edge in the width direction of a roll, and within 50 mm from the other end edge Samples were cut out from the respective positions, and HS150, which is the heat shrinkage rate in the film winding direction when heated at 150 ° C. for 30 minutes, was obtained for the two samples, and the difference in heat shrinkage rate, which was the difference between the HS150, was obtained. Sometimes, it is necessary that all the heat shrinkage difference in all cutout portions is 0.7% or less.

  That is, the polyester-based resin film roll of the present invention has a total of 10 heat shrinkage ratio differences (difference in HS150 at both end edges in the film sample cut out from each cut-out portion) obtained in a total of 10 cut-out portions. It is necessary to be 0.7% or less. If the heat shrinkage difference in each cut-out portion exceeds 0.7%, the film passability in post-heat treatment is deteriorated, which is not preferable. Further, the difference in heat shrinkage rate between the cutout portions is more preferably 0.6% or less, and particularly preferably 0.5% 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 sample in the present invention is cut out from 10 cut-out portions provided by the following procedure. The “within” in the sample cutout part of the present invention is cut out from the designated position in principle, but it may be set to the inside from the designated position from the relationship of the width of the sample. It means that it doesn't matter.
(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 off at a distance of 55 ± 10 m from the winding end of the film. 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 polyester-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 in each cut-out portion when the sample cut-out portion is set by the above-described method. When samples are cut out from the respective positions and the HS 150 is obtained for each sample, the HS 150 of the samples at both end edges in all cut-out portions must be 1.2% or more and 4.5% or less. .

  That is, in the polyester-based resin film roll of the present invention, in the total of 10 cutout portions, the HS150 values (total 20 HS150 values) at the both end edges of the cut out film samples are all 1.2% or more. It is necessary to be 4.5% or less. If the value of HS150 at both ends of the film sample cut out from each cut-out part exceeds 4.5%, the passability of the film in the post-heat treatment will be unfavorable. Moreover, the value of HS150 at the both ends of the film sample cut out from each cut-out portion is more preferably 4.2% or less, and particularly preferably 4.0% or less. In addition, although the value of HS150 in the both ends of the film sample cut out from each cutout part is so preferable that it is low, about 1.2% is considered to be a minimum.

  Furthermore, the polyester-based resin film roll of the present invention has a variation amount of HS150 on one end edge side in the roll width direction obtained in each cutout part, and HS150 on the other end edge side in the roll width direction obtained in each cutout part. The amount of variation needs to be 0.4% or less.

  That is, the polyester-based resin film roll of the present invention has HS150 on one end edge side (one end edge side in the width direction) and HS150 on the other end side (the other end edge side in the width direction) for 10 films cut out from each cutout portion. When obtained, the fluctuation amount (difference between the highest value and the lowest value) of the ten HS 150 on the one end side is 0.4% or less, and the fluctuation amount of the ten HS 150 on the other end side is 0.4. % Or less. If the fluctuation amount of 10 HS 150 on either edge side exceeds 0.4%, it is not preferable because the film passability in post-heat treatment is deteriorated. Further, it is particularly preferable that the fluctuation amount of the ten HS 150 on each edge side is 0.35% or less. In addition, although the variation | change_quantity of 10 HS150 of 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.

[Method for producing polyester resin film roll]
The polyester-based resin film roll of the present invention is obtained by melt-extrusion of a raw material copolymer polyester alone, a blend of one or more homopolyesters or copolymer polyesters, or a combination of homopolyester and copolymer polyester. The biaxially stretched unstretched film (unstretched laminated film or unstretched laminated sheet) in the longitudinal direction (longitudinal direction) and the transverse direction (width direction) and then wound into a roll and heat-fixed by the method described later Can be manufactured.

  The method for producing the biaxially oriented polyester resin film is not particularly limited.For example, after drying the polyester resin as necessary, it is supplied to a known melt extruder and extruded into a sheet form from a slit die, Examples include a method in which the unstretched sheet is biaxially stretched after being brought into close contact with a casting drum by a method such as electrostatic application, cooled and solidified to obtain an unstretched sheet.

  As the biaxial stretching method, a method is employed in which an unstretched sheet is stretched and heat-treated in the longitudinal direction (MD) and width direction (TD) of the film to obtain a biaxially stretched film having a desired in-plane orientation degree. . Among these methods, in terms of film quality, the MD / TD method in which the film is stretched in the longitudinal direction and then stretched in the width direction, or the TD / MD method in which the film is stretched in the width direction and then stretched in the longitudinal direction. An axial stretching method is appropriately used.

  The film stretching ratio when biaxially stretching is preferably 1.6 to 4.2 times in the longitudinal direction and the width direction, particularly preferably 1.7 to 4.0 times. In this case, the stretching ratio in the longitudinal direction and the width direction may be either larger or the same ratio. More preferably, the stretching ratio in the longitudinal direction is 2.8 to 4.0 times, and the stretching ratio in the width direction is 3.0 to 4.5 times.

  As the stretching conditions for producing the molding polyester film of the present invention, it is preferable to select, for example, the following conditions.

  In the longitudinal stretching, the stretching temperature is more preferably 50 to 110 ° C. so that the subsequent lateral stretching can be performed smoothly.

  Usually, when stretching the polyethylene terephthalate, if the stretching temperature is lower than the appropriate conditions, the yield stress increases rapidly at the beginning of the lateral stretching, and therefore stretching cannot be performed. Moreover, even if it can extend | stretch, since thickness and a draw ratio become easy to become nonuniform, it is unpreferable.

  In addition, when the stretching temperature is higher than appropriate conditions, the initial stress is low, but the stress does not increase even when the stretch ratio is high. Therefore, the film has a small stress at 100% elongation at 25 ° C. Therefore, by taking the optimum stretching temperature, a highly oriented film can be obtained while ensuring stretchability.

  However, when the copolymerized polyester contains 1 to 40 mol% of a copolymer component, the stretching stress rapidly decreases as the stretching temperature is increased so as to eliminate the yield stress. In particular, since the stress does not increase even in the latter half of the stretching, the orientation does not increase and the stress at 100% elongation at 25 ° C. decreases.

  Such a phenomenon is likely to occur when the thickness of the film is 10 to 500 μm, and is particularly noticeable in a film having a thickness of 20 to 300 μm. Therefore, in the case of a film using the copolymerized polyester of the present invention, the stretching temperature in the transverse direction is preferably set as follows.

  First, preheating temperature is performed in the range of +10 degreeC-+50 degreeC of the glass transition temperature at the time of measuring the mixture after extruding film material with an extruder in DSC. Next, in the first half of the transverse stretching, the stretching temperature is preferably −20 ° C. to + 15 ° C. with respect to the preheating temperature. In the latter half of the transverse stretching, the stretching temperature is preferably 0 ° C. to −30 ° C., particularly preferably −10 ° C. to −20 ° C. with respect to the stretching temperature of the first half. By adopting such conditions, the first half of the transverse stretching is easy to stretch because the yield stress is small, and the second half is easily oriented.

  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 width relaxation rate is preferably 1 to 10%. If it is less than 1%, the effect is small, and if it exceeds 10%, the flatness of the film deteriorates, which is not preferable.

  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.

  The thickness of the film which comprises the polyester-type resin film roll of this invention is not specifically limited. However, the thickness of the polyester resin film roll is preferably 10 μm or more and 500 μm or less. The lower limit of the thickness of the polyester resin film roll is preferably 20 μm or more, and more preferably 50 μm or more. If the film thickness is 10 μm or more, the strength required for processing such as molding can be obtained. Moreover, the upper limit of the thickness of the polyester resin film roll is preferably 400 μm or less, and more preferably 300 μm or less. If the film thickness is 500 μm or less, processing such as molding is possible.

  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. Accordingly, when the thickness of the film is in the middle of 10 to 400 μm, it is preferable to set the winding 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 polyester-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 is post-processed on one side or both sides of a biaxially stretched polyester-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 adhesion during the process and the purpose of improving the slipperiness.

  Moreover, in order to improve handling properties, such as the slipperiness and winding property of a film, it is preferable to form an unevenness | corrugation on the film surface. As a method for forming irregularities on the film surface, a method of incorporating particles in the film is generally used.

  Examples of the particles include internal particles having an average particle size of 0.01 to 10 μm, external particles such as inorganic particles and / or organic particles. When particles having an average particle diameter exceeding 10 μm are used, defects in the film are liable to occur, and the design and transparency tend to deteriorate. On the other hand, in the case of particles having an average particle diameter of less than 0.01 μm, handling properties such as film slipperiness and winding property tend to be lowered. The lower limit of the average particle diameter of the particles is more preferably 0.10 μm, particularly preferably 0.50 μm, from the viewpoint of handling properties such as slipping property and winding property. On the other hand, the average particle diameter of the particles is more preferably 5 μm, particularly preferably 2 μm, from the viewpoint of transparency and reduction of film defects due to coarse protrusions.

  The average particle size of the particles is taken by taking a plurality of photographs of at least 200 particles by electron microscopy, tracing the outline of the particles on an OHP film, and converting the trace image to an equivalent circle diameter with an image analyzer. To calculate.

  Examples of the external particles include wet and dry silica, colloidal silica, aluminum silicate, titanium oxide, calcium carbonate, calcium phosphate, barium sulfate, alumina, mica, kaolin, clay, hydroxyapatite and the like, and styrene, silicone, acrylic Organic particles or the like containing acids as constituent components can be used. Among these, inorganic particles such as dry, wet and dry colloidal silica and alumina, and organic particles containing styrene, silicone, acrylic acid, methacrylic acid, polyester, divinylbenzene and the like as constituent components are preferably used. Two or more of these internal particles, inorganic particles and / or organic particles may be used in combination as long as the characteristics defined in the present invention are not impaired.

  Furthermore, the content of the particles in the film is preferably in the range of 0.001 to 10% by mass. When the amount is less than 0.001% by mass, the handling property is likely to be deteriorated, for example, the slipperiness of the film is deteriorated or winding becomes difficult. On the other hand, if it exceeds 10% by mass, it tends to cause formation of coarse protrusions, deterioration of film forming property and transparency.

  Moreover, since the particle | grains contained in a film generally differ in refractive index from polyester, it becomes a factor which reduces the transparency of a film. In many cases, the molded product is printed on the surface of the film before the film is molded in order to improve the design. Since such a printing layer is often applied to the back side of a molding film, it is desired that the transparency of the film is high from the viewpoint of printing clarity.

  Therefore, in order to obtain a high degree of transparency while maintaining the handleability of the film, the particles are not substantially contained in the base film of the main layer, and the particles are only in the surface layer having a thickness of 0.01 to 5 μm. It is effective to use a laminated film having a laminated structure containing. The upper limit of the thickness of the surface layer is preferably 3 μm, particularly preferably 1 μm. In this case, the particles exemplified above can be used.

  Note that “substantially no particles are contained in the base film” as used above means, for example, in the case of inorganic particles, the content that is below the detection limit when inorganic elements are quantified by fluorescent X-ray analysis. means. This is because contaminants derived from foreign substances may be mixed without intentionally adding particles to the base film.

  The thin surface layer can be formed by a coating method or a coextrusion method. Especially, in the case of the coating method, since the adhesiveness with a printing layer can also be improved by using the composition which consists of adhesiveness modification resin containing particle | grains as an application layer, it is a preferable method. As said adhesive property modification resin, resin which consists of at least 1 sort (s) chosen from polyester, a polyurethane, an acrylic polymer, and / or those copolymers is preferable.

  As the particles to be contained in the surface layer, the same particles as those described above can be used. Among the particles, silica particles, glass fillers, and silica-alumina composite oxide particles are particularly suitable from the viewpoint of transparency because the refractive index is relatively close to that of polyester.

  Furthermore, the particle content in the surface layer is preferably in the range of 0.01 to 25% by mass. When the content is less than 0.01% by mass, handling properties are likely to deteriorate, for example, the slipperiness of the film is deteriorated or winding becomes difficult. On the other hand, when it exceeds 25 mass%, transparency and applicability tend to deteriorate.

  In order to impart other functions, the polyester film of the present invention can be made into a laminated structure by a known method using different types of polyester. The form of the laminated film is not particularly limited. For example, the laminated film has an A / B two-kind two-layer structure, a B / A / B two-kind three-layer structure, and a C / A / B three-kind three-layer structure. The form is mentioned

  Furthermore, the polyester 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 polyester-type resin film roll of this invention is demonstrated.

[Heat setting method]
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.

  When the inventors attached a continuous large shielding plate to the hot air outlet of the plenum duct, why "passability in a long film" or "when heat fixing treatment in post-processing is performed at a high temperature In order to ascertain whether the “passability of” is not improved, the phenomenon in the heat setting device was analyzed in detail. As a result, when a continuous large shielding plate spanning a plurality of plenum ducts is put on the hot air outlet of the plenum duct, the flow of hot air blown from the hot air outlet of the plenum duct is significantly limited by the shielding plate, It has been found that a temperature hunting phenomenon occurs in the heat fixing device due to the fact that the above-mentioned "hot air circulation" is not performed smoothly.

The present inventors have described that the above-mentioned “temperature hunting phenomenon” induces insufficient thermal relaxation at the edge of the film, such as “passability in a long film” and “heat setting treatment in post-processing. It was speculated that it may have an adverse effect on the “passability when it is carried out at a high temperature”. Furthermore, the present inventors controlled the conditions such as the temperature and the air volume of the heat fixing device, and improved the coating method when covering the hot air outlet of the plenum duct with a shielding plate, thereby making the “hot air” described above. ”Circulation” can be performed smoothly, and “temperature hunting phenomenon” can be suppressed. As a result, “passability in long films” and “heat setting in post-processing are performed at high temperatures” It was speculated that it would be possible to improve the "passability when And as a result of trial and error to grasp the relationship between the temperature of the heat setting device, the air flow condition, the covering mode of the shielding plate, and the film permeability in the post-processing, the following (1) By adopting the means, 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) Adjustment of the temperature and air volume of the plenum duct in the heat setting device In the production of the film roll of the present invention, the product of the temperature difference and the wind speed difference between the adjacent heat setting zones of the heat setting device, It is essential to adjust the temperature and air volume of the hot air blown out from each plenum duct so that it becomes 250 ° C. · m / s or less. 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 the product of the temperature difference and the wind speed difference need to be adjusted to be 250 ° C. · m / s or less. In such a case, a discontinuous shielding plate is attached to the hot air outlet of the plenum duct as described later by adjusting the temperature and air volume of the hot air blown from the hot air outlet of the plenum duct in each heat fixing zone. In addition, “circulation of hot air” in the heat setting device is executed smoothly, and “temperature hunting phenomenon” is effectively suppressed. However, it becomes possible to obtain a long film having a good length.

  When the product of the temperature difference and the wind speed difference between adjacent heat setting zones exceeds 250 ° C. · m / s (for example, the temperature difference between adjacent heat setting zones is set to 30 ° C. In addition, if the difference in wind speed between adjacent heat setting zones is set to 10 m / s), the “hot air circulation” in the heat setting device will not be performed smoothly, effectively preventing the “temperature hunting phenomenon”. Since it becomes impossible to suppress, it is not preferable. In addition, when the product of the temperature difference and the wind speed difference between the adjacent heat setting zones exceeds 250 ° C. · m / s, as an accompanying flow caused by the passage of the film, from the upstream heat setting zone to the downstream heat setting zone The amount of heat of the air flowing in becomes large, which adversely affects the temperature stability in the width direction of the downstream heat setting zone. 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 Shut-off Conditions in Heat Fixing Device In manufacturing the film roll of the present invention, as described above, the temperature and air volume of hot air blown from the hot air outlet of the plenum duct are adjusted in each heat fixing zone. In addition, instead of attaching a large replacement portable shielding plate across a plurality of plenum ducts arranged in the heat fixing device, as shown in FIG. 2, hot air outlets (nozzles) of individual plenum ducts 3, 3,. It is necessary to attach rod-shaped shielding plates S, S,... To shield 2, 2,. In addition, when attaching a rod-shaped shielding plate to each plenum duct, the length of the shielding plate is gradually increased from the inlet to the outlet of the heat fixing device instead of attaching the same length of shielding plate to each plenum duct. It is preferable to lengthen the length (see FIG. 1). The material of the shielding plate is preferably the same material as the plenum duct in consideration of the thermal expansion in the heat fixing device, but can withstand the temperature of the heat fixing device and stain the film, There is no particular limitation as long as the film is not adhered. Further, in order to suppress the difference in thermal contraction rate of the film edge portion due to the shielding plate to the level of the present invention, it is preferable that the number of shielding plates is large, and it is desirable that the number is 15 or more.

(3) Blocking of heating between the stretching zone and the heat setting device (installation of an intermediate zone)
The biaxially stretched copolyester-based resin film roll is usually manufactured by being heat-set after being longitudinally and laterally stretched as described above. In the production of the film roll of the present invention, An intermediate zone that does not blow active hot air between the transversely stretched zone and the heat-fixing device that is heat-set is installed to completely block the heat between the stretching zone and the heat-fixing device. It is preferred to do so. More specifically, the stretching zone and the heat setting device are adjusted to the same conditions as in the film production, and when the strip-shaped paper piece is hung between the stretching zone and the heat setting device in that state, the piece of paper is It is preferred to block the hot air from the stretching zone and the heat setting device so that it hangs almost completely in the vertical direction. In addition, the intermediate zone which does not perform such hot air blowing may be surrounded by a housing, or may be provided so that a continuously manufactured film is exposed. Insufficient blocking of the hot air in the intermediate zone is not preferable because the shielding effect of the shielding plate in the heat fixing device is insufficient, and good film permeability during post-processing cannot 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.

  In order to achieve both the haze and surface roughness of the polyester resin film of the present invention, that is, the slipperiness of the film, it is particularly important to set the temperatures of the heat setting zones of the front and rear stages. Preferred embodiments of the heat treatment temperature are as follows. The heat treatment temperature of the front stage is −5 ° C. to −30 ° C. of the heat treatment temperature of the rear stage, the lower limit is preferably −10 ° C., and the upper limit is preferably −25 ° C. The heat treatment temperature at the rear stage is in the range of −5 ° C. to −35 ° C. of the melting point when the mixture obtained by extruding the film material with an extruder is measured by DSC. The lower limit is preferably −10 ° C., and the upper limit is preferably −30 ° C. By taking such conditions, a film having a low haze and good sliding properties can be obtained.

  The reason is considered as follows. A polyester film containing about 5 to 50 mol% of a copolymer component as in the present invention has a lower crystallization speed and lower crystallinity than a polyethylene terephthalate film. Therefore, when heat treatment is performed rapidly at a high temperature after the end of stretching, the mobility of molecules constituting the material having low crystallinity is increased in the heat treatment zone. Therefore, the surface protrusions formed by the bulging of the particles (particles in the film and / or particles of the coating layer) in the stretching process are buried again in the heat treatment zone, so that sufficient surface roughness is obtained. I can't. Therefore, in order to wind up the film neatly, the content of the particles is increased more than necessary, which causes a decrease in haze. On the other hand, if the heat treatment temperature at the rear stage is lower than a predetermined temperature, a film having a sufficiently low thermal shrinkage at 150 ° C. cannot be obtained.

  Therefore, by setting the heat treatment temperature in the above-described manner, the crystallization of the film is promoted to some extent before the particles are buried inside the film at the heat treatment temperature of the preceding stage, and the temperature is sufficiently increased in the TS2 zone. However, compared with the state of the previous term, the mobility of the molecules is sufficiently lowered, and the film having a low thermal shrinkage rate can be obtained by further promoting the crystallinity while forming the projections on the surface. Moreover, the addition of more than necessary particles can be prevented.

  In general, as a means for lowering the degree of plane orientation, a method of lowering the draw ratio and a method of increasing the blending amount of the copolymer component are known, but the former method deteriorates the thickness unevenness of the film. This is not preferable because the melting point is lowered and the heat resistance is deteriorated. In the present invention, in order to reduce the plane orientation degree of the biaxially oriented polyester film and the thermal shrinkage at 150 ° C., heat setting is performed at a higher temperature than usual.

  Also, when copolymer polyester is used as a biaxially oriented polyester film, the resin melting point is lower than that of a homogeneous polymer, so if the heat setting temperature is increased, the film is difficult to peel off to the clip that holds the film in the transverse stretching step. Become. Therefore, it is important to sufficiently cool the vicinity of the clip when the clip releases the film at the tenter outlet. Specifically, in order to make it easy to peel the film and the clip, (1) a method of providing a heat shielding wall on the clip portion so that the clip is hardly heated, and (2) a method of adding a clip cooling mechanism to the tenter. (3) A method in which the cooling section after heat setting is set long in order to enhance the cooling capacity, and the entire film is sufficiently cooled. (4) The cooling efficiency is increased by increasing the length of the cooling section and the number of sections. It is preferable to employ a method of increasing the clip, and (5) a method of enhancing the cooling of the clip by using a type in which the return portion of the clip travels outside the furnace.

  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. . The film properties obtained in each example were measured and evaluated by the following methods.

(1) Intrinsic viscosity 0.1 g of a chip sample was precisely weighed, dissolved in 25 ml of a mixed solvent of phenol / tetrachloroethane = 60/40 (mass ratio), and measured at 30 ° C. using an Ostwald viscometer. In addition, the measurement was performed 3 times and the average value was calculated | required.

(2) Glass transition temperature (Tg) and melting point (Tm) of the resin
The melting point is an endothermic peak at the time of melting, which is detected at the time of primary temperature increase of so-called differential scanning calorimetry (DSC). Using a differential scanning calorimeter (Mac Science, DSC3100S), about 7 mg of resin extruded under the conditions of each example was placed in a sample pan, the pan was capped, and the temperature was increased from room temperature to 300 ° C. in a nitrogen gas atmosphere. The temperature was measured at a temperature increase rate of 20 ° C./min. The melting point (Tm: ° C.) was determined based on JIS-K7121-1987, 9.1, and the glass transition temperature (Tg: ° C.) was determined based on 9.3.

(3) Film thickness Using a thickness meter (Millitron manufactured by Fine Reef Co., Ltd.) Millitron, 15 points were measured per roll, and the average value was determined.

(4) Measurement of Δn _{ab After} each sample film cut out from each sample cut-out part was left in an atmosphere of 23 ° C. and 65% RH for 2 hours or more, “Abbe refractometer 4T type” manufactured by Atago Co., Ltd. was used. A refractive index in a direction that forms an angle of 45 degrees with the winding direction of the wound film, and a direction that forms an angle of 135 degrees with the winding direction of the wound film (that is, the angle of 45 degrees described above) Refractive index in a direction forming 90 degrees and a direction forming an angle of 90 degrees was measured. The calculated absolute value of the difference between the two refractive index thereof as [Delta] n _ab. 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.

(5) Thermal contraction rate of film The first sample cutout portion is provided within 2 m from the end of winding of the film, and the sample cutout portion is provided for every length obtained by dividing the winding length of the film into 9 equal parts from the end of winding of the film. By providing the final cutout portion within 2 m from the start of film winding, a total of 10 sample cutout portions were provided for one film roll. 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 was measured in accordance with JIS C-2318.

(6) Film permeability The flatness of the film in 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 150 ° 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.

[Example 1]
Copolymer polyester chip having an intrinsic viscosity of 0.69 dl / g, comprising 100 mol% of terephthalic acid units as aromatic dicarboxylic acid components, 40 mol% of ethylene glycol units and 60 mol% of neopentyl glycol units as diol components. Polyethylene terephthalate containing 0.04% by mass of (A) and silica having an intrinsic viscosity of 0.69 dl / g and an average particle size (SEM method, the same applies hereinafter) of 2.7 μm (Silicia 310P manufactured by Fuji Silysia) Each chip (B) was dried. Furthermore, the chip (A) and the chip (B) were mixed so as to have a mass ratio of 25:75. Subsequently, these chip mixtures were melt-extruded from the slit of the T die at 270 ° C. with an extruder, rapidly cooled and solidified on a chill roll having a surface temperature of 40 ° C., and at the same time, the amorphous mixture was adhered to the chill roll using an electrostatic application method. A stretched sheet was obtained.

  The obtained unstretched sheet was stretched 3.3 times at 90 ° C. in the longitudinal direction between the heating roll and the cooling roll. Next, the uniaxially stretched film was guided to a tenter, preheated at 120 ° C. for 10 seconds, and the first half of the transverse stretching was stretched 3.9 times at 110 ° C. and the latter half at 100 ° C. Furthermore, a heat setting treatment was performed by a method described later while performing a relaxation treatment of 7% in the lateral direction. By winding this 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 6,500 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, Six slit rolls having a width of 1,000 mm and a winding length of 3,010 m were obtained. Of the six slit rolls obtained as described above, 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), the characteristics of the film and the film roll Was evaluated. The evaluation results are shown in Table 6.

[Heat setting]
The heat setting process was performed by a heat setting apparatus having a structure as 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 each of the first to third zones, and 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. And hot air is sprayed on the film extended | stretched from the hot air blowing outlet (nozzle) of those plenum ducts. In addition, an external return method is used as a clip return method, and a clip cooling device is installed, and forced cooling is performed with cold air of 20 ° C, and clip fusing prevention measures are taken so that the clip temperature at the tenter outlet is 40 ° C or lower. It was.

  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. Further, the length of each shielding plate S, S... (The dimension in the width direction of the film to be manufactured) is adjusted so that it gradually becomes wider (that is, widens toward the end) from the inlet to the outlet of the heat fixing device. Has been. Table 7 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."

  Further, in Example 1, the temperature and wind speed of the first to fourth zones of the heat fixing device were adjusted as shown in Table 8. In addition, in 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 the adjacent heat setting zones and the wind speed difference is 250 ° C. · m / s or less. The temperature and wind speed conditions in the first to fourth zones in Example 1 are defined as “I condition”.

[Example 2]
Silica (Silicia 310P manufactured by Fuji Silysia Co., Ltd.) having an average particle size of 2.7 μm comprising 88 mol% terephthalic acid unit and 12 mol% isophthalic acid as the aromatic dicarboxylic acid component, and 100 mol% ethylene glycol unit as the diol component. A copolymer polyester chip (C) containing 0.05% by weight with an intrinsic viscosity of 0.65 dl / g and an intrinsic viscosity of 0.9 dl / g (measured in o-chlorophenol at 35 ° C.) The polybutylene terephthalate chip (D) was dried, and the chip (C) and the chip (D) were mixed at a mass ratio of 55:45, and then amorphous as in Example 1. These chip mixtures were melt extruded at 270 ° C. from the slits of the T-die using an extruder, and a chip having a surface temperature of 20 ° C. was obtained. Quenched and solidified on a roll to obtain an undrawn sheet of amorphous while in close contact with the chill roll using an electrostatic application method simultaneously.

  The obtained unstretched sheet was stretched 3.0 times at 70 ° C. in the longitudinal direction between the heating roll and the cooling roll. Next, the uniaxially stretched film was guided to a tenter and stretched 3.0 times in the transverse direction at 80 ° C. Furthermore, the thickness of 50 μm was the same as in Example 1 except that the temperature and wind speed of the first to fourth zones of the heat setting device were changed to the adjustment values shown in Table 5 and the lateral relaxation rate was changed to 3%. A biaxially oriented polyester film roll (mill roll) was prepared by winding a film having a width of 3,300 mm for 6,500 m. 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, Six slit rolls having a width of 1,000 mm and a winding length of 3,010 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 1. The evaluation results are shown in Table 6. Note that the temperature and wind speed conditions of the first to fourth zones in Example 2 are referred to as “II conditions”.

[Example 3]
True spherical silica particles having an average particle size of 1.5 μm, comprising 100 mol% terephthalic acid unit as the aromatic dicarboxylic acid component, 70 mol% ethylene glycol unit and 30 mol% 1,4-cyclohexanedimethanol unit as the diol component (Nippon Shokubai Co., Ltd., Seahoster KE-P150) 0.01% by weight of copolymer polyester chip (E) having an intrinsic viscosity of 0.71 dl / g and true spherical silica particles having an average particle size of 0.1 μm Polyethylene terephthalate chips (F) having an intrinsic viscosity of 0.69 dl / g containing 0.06% by weight (Nippon Shokubai Co., Ltd., Seahoster KE-P10) were dried. Further, the chip (E) and the chip (F) were mixed so as to have a mass ratio of 50:50, and this was used for the B layer (skin layer).

    Consists of a polyethylene terephthalate chip (G) with an intrinsic viscosity of 0.69 dl / g, 100 mol% terephthalic acid unit as the aromatic dicarboxylic acid component, 70 mol% ethylene glycol unit and 30 mol% neopentyl glycol unit as the diol component. The component polyester chip (H) having an intrinsic viscosity of 0.71 dl / g and the polypropylene terephthalate chip (I) having an intrinsic viscosity of 0.69 dl / g were dried. Furthermore, chip (G), chip (H), and chip (I) were mixed at a mass ratio of 30:30:40, and this was used for the A layer (core layer).

  Using a co-extrudable extruder having a feed block and a T die, the B layer resin and the A layer resin were coextruded. The layer configuration was BAB extruded at a thickness ratio of 8: 84: 8. In the same manner as in Example 1, an amorphous unstretched sheet was obtained.

  The obtained unstretched sheet was stretched 3.3 times at 88 ° C. in the longitudinal direction between the heating roll and the cooling roll. Next, the uniaxially stretched film was guided to a tenter and preheated at 100 ° C. for 3 seconds, and the first half of the transverse stretching was stretched 3.8 times in the transverse direction at 100 ° C. and the latter half at 95 ° C. Further, the shielding plate attached to the hot air outlet of each plenum duct of the heat fixing device is changed to have the shielding rate shown in Table 4, and the temperatures and wind speeds of the first to fourth zones of the heat fixing device are shown in Table 5. A biaxially oriented polyester film roll in which a film having a thickness of 100 μm and a width of 3,300 mm was wound up by 6,500 m (except for changing to an adjustment value and changing the lateral relaxation rate to 5%) Mill roll) 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, Six slit rolls having a width of 1,000 mm and a winding length of 3,010 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 1. The evaluation results are shown in Table 6. 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 "III conditions."

[Example 4]
100 mol% of terephthalic acid units as aromatic dicarboxylic acid components, 99 mol% of ethylene glycol units and 1 mol% of diethylene glycol units as diol components, and spherical silica particles having an average particle size of 1.5 μm (manufactured by Nippon Shokubai Co., Ltd., Containing 0.01% by weight of Seahoster KE-P150) and 0.06% by weight of true spherical silica particles (Nippon Shokubai Co., Ltd., Seahoster KE-P10) having an average particle diameter of 0.1 μm, and having an intrinsic viscosity of 0.65 dl / The polyethylene terephthalate chip (K) of g was dried and used for the B layer (skin layer).

  Intrinsic viscosity is 0.6 dl, comprising 88 mol% terephthalic acid units and 12 mol% 6-naphthalenedicarboxylic acid units as aromatic dicarboxylic acid components, and 98 mol% ethylene glycol units and 2 mol% diethylene glycol units as diol components. / G copolymer polyester chip (J) was dried and used for layer A (core layer).

  Using a co-extrudable extruder having a feed block and a T die, the B layer resin and the A layer resin were coextruded. The layer composition was BAB extruded at a thickness ratio of 5: 90: 5. In the same manner as in Example 1, an amorphous unstretched sheet was obtained.

  The obtained unstretched sheet was stretched 3.0 times at 110 ° C. in the longitudinal direction between the heating roll and the cooling roll. Next, the uniaxially stretched film was guided to a tenter, and stretched 3.8 times in the transverse direction at 120 ° C. Furthermore, the thickness of 100 μm in the same manner as in Example 1 except that the temperature and wind speed of the first to fourth zones of the heat setting device were changed to the adjustment values shown in Table 5 and the lateral relaxation rate was changed to 5%. A biaxially oriented polyester film roll (mill roll) was prepared by winding a film having a width of 3,300 mm for 6,500 m. 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, Six slit rolls having a width of 1,000 mm and a winding length of 3,010 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 1. The evaluation results are shown in Table 6. Note that the temperature and wind speed conditions of the first to fourth zones in Example 4 are referred to as “IV conditions”.

[Example 5]
The shielding plate attached to the hot air outlet of each plenum duct of the heat setting device is changed so as to have the shielding rate shown in Table 4, and the temperature and wind speed of the first to fourth zones of the heat setting device are adjusted values shown in Table 4. 10 slit rolls were obtained in the same manner as in Example 1 except that the number of slit rolls was changed. 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 6. Note that the temperature and wind speed conditions of the first to fourth zones in Example 5 are defined as “V conditions”.

[Comparative Example 1]
Six slit rolls were obtained in the same manner as in Example 1 except that an integrated large shielding plate was attached to the hot air outlet of each of the plenum ducts a to o of the heat fixing device. 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 6.

[Comparative Example 2]

While changing the shielding mode by the rod-shaped shielding plate attached to the hot air outlet of each of the plenum ducts a to o of the heat fixing device as shown in Table 4, the temperatures and wind speeds of the first to fourth zones of the heat fixing device are also shown. Except having changed to each adjustment value shown in 5, it carried out similarly to Example 1, and obtained six slit rolls. In addition, the length of the film width direction of each shielding plate in Comparative Example 2 is adjusted so as to gradually become narrower from the inlet to the outlet of the heat fixing device. Further, the shielding mode by the shielding plate in Comparative Example 2 is set as “C mode”, and the temperature and wind speed conditions in the first to fourth zones in Comparative Example 4 are set as “VI conditions”. 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 6.

[Comparative Example 3]
The heat fixation was carried out without attaching a shielding plate to the hot air outlet of each plenum duct, and the temperature and wind speed of the first to fourth zones of the heat fixation device were changed as shown in Table 8 in the same manner as in Example 1. 6 slit rolls were obtained. Note that the temperature and wind speed conditions in the first to fourth zones in Comparative Example 3 are referred to as “VII conditions”. 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 6.

Regarding Examples 1 to 4 and Comparative Examples 1 to 3, the raw material composition and polymer characteristics of the polymer chips used are shown in Table 1, the resin characteristics and film forming conditions of the film roll are shown in Table 2, and the conditions of the heat setting treatment are shown. 3 to 5 show the properties of the film roll in Table 6.

[Effects of Example Film]
From Table 4, the film rolls of the examples all have a small difference in heat shrinkage rate (that is, a difference in heat shrinkage rate) over the entire width of the roll, and also a small amount of variation in the heat shrinkage rate in the longitudinal direction. It can be seen that the passability in is good and suitable for post-processing. On the other hand, the film roll of the comparative example has a large difference in heat shrinkage rate over the entire width of the roll and also has a large amount of fluctuation in the heat shrinkage rate in the longitudinal direction, indicating that the passability during post-processing is poor.

  Since the copolymerized polyester resin film roll of the present invention has excellent processing characteristics as described above, the heat treatment in the optical film used for various optical members and other post-processing is performed in the high temperature zone (160 It can be suitably used as a film for processing carried out over a relatively long time (10 to 60 seconds) at about [deg.] C.

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.

Explanation of symbols

  1. Heat fixing device, 2. Hot air outlet, 3, ax, Plenum duct, A, Film traveling direction, F Film, S, Shield plate, Z1-4 Heat fixing zone.

Claims (4)

A polyester 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 is wound, and the winding direction of the wound film is 45 degrees. Polyester resin film in which Δn _ab is 0.020 or more and 0.080 or less, which is the difference between the refractive index in the direction forming the angle and the winding direction of the wound film and the refractive index in the direction forming the angle of 135 degrees A roll,
Coiled thickness of the polyester based resin film is at 10μm or 500μm or less, the film is melting point consists 180 to 250 ° C. polyester resin,
The polyester resin is a blend of homopolyester and copolymerized polyester,
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 polyester-based resin film roll characterized by satisfying the following requirements (1) to (3) when a total of 10 sample cutout portions are provided by providing sample cutout portions on the plate.
(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 film winding direction is obtained, and when the heat shrinkage rate difference which is the difference between the HS150 is obtained, the heat shrinkage rate difference in all cut-out portions is 0.7% 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 HS150 is obtained for each sample, HS150 of the samples at both end edges in all cutouts is 1.2% or more and 4.5% or less 3) The fluctuation amount of the HS 150 on the one end edge side in the width direction of the roll obtained in each cutout portion and the fluctuation amount of the HS150 on the other end edge side in the width direction of the roll obtained in each cutout portion are both 0. 4% or less It is a manufacturing method for manufacturing the polyester-type resin film roll described in Claim 1, Comprising:
A film forming process for forming an unstretched sheet by melt-extruding a raw material resin from an extruder, a biaxial stretching process for biaxially stretching the unstretched sheet obtained in the film forming process in the longitudinal direction and the transverse direction, A heat setting step of heat fixing the film after axial stretching,
The manufacturing method of the polyester-type resin film roll characterized by performing the heat setting process in the heat setting apparatus which satisfy | fills the following requirements (4)-(7).
(4) A plurality of wide plenum ducts for blowing out hot air are arranged vertically opposite to the traveling direction of the film. (5) Shielding for shielding hot air outlets from the plurality of plenum ducts. (6) 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. (7) The air speed of the plenum duct in each heat setting zone is made constant. 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 manufacturing method of the polyester-type resin film roll of Claim 2 characterized by these. 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 polyester-type resin film roll of Claim 2 or Claim 3 characterized by the above-mentioned.

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