WO2023223903A1

WO2023223903A1 - Film roll holding device, method of preventing failure in film roll, and control program

Info

Publication number: WO2023223903A1
Application number: PCT/JP2023/017528
Authority: WO
Inventors: 絢斗長井; 修増田; 由紀金子; 崇南條
Original assignee: コニカミノルタ株式会社
Priority date: 2022-05-17
Filing date: 2023-05-10
Publication date: 2023-11-23

Abstract

A film roll holding device (1) comprises: a measurement part (40) that generates measurement data by measuring a side surface of a film roll (80) held by a holding part (30); an analysis part (11) that generates an indication value related to a void between film layers by analyzing the measurement data; and a prevention control part (13) that determines whether a temporal change in the indication value has exceeded a threshold, and that, upon determining that the temporal change has exceeded the threshold, rotates the film roll (80) by a predetermined amount by means of a rotation mechanism (313).

Description

Film roll holding device, film roll failure suppression method, and control program

The present invention relates to a film roll holding device for holding a film roll in which a film used for a liquid crystal display (LCD) or the like is wound into a roll, a failure prevention method for this film roll, and a control program.

Liquid crystal display devices are increasingly being used in large-screen televisions and large monitors, and along with this, the films used for the display surfaces of liquid crystal display devices are also required to be wider. For example, there is a demand for a wide fin with a width of 2000 mm or more. Furthermore, in order to account for base material loss (film loss) in advance and to reduce transportation costs, it is required to manufacture long film rolls with a winding length of 1000 m or more, and even 3000 m or more.

There are cases where such film rolls are left unused for a long period of time after being manufactured, or left unused for a long time after being delivered to a customer. As a result, the entire film roll undergoes deformation due to deflection due to the weight of the film base material, which causes the films to stick to each other or undergo buckling deformation, resulting in quality defects (failures).

Patent Document 1 discloses a storage box and a storage method for preventing film rolls from being bent or stuck during storage or transportation. In this storage method, a film roll (original film) stored in a storage box is rotated by a rotating means at least once every two weeks, thereby suppressing failure.

Japanese Patent Application Publication No. 2005-241793

However, depending on the material, width, thickness, surface properties, storage environment, etc. of the film to be wound, the length of time a stored film roll is left unused for failure to occur is not uniform, and the storage method disclosed in Patent Document 1 is not suitable for this purpose. There is a risk that failures may not be suppressed. Further, it is thought that failures can be suppressed by increasing the frequency of rotation, but in order to suppress failures under all conditions, it is necessary to rotate at a high frequency, which is not realistic.

The present invention has been made in view of the above circumstances, and an object of the present invention is to provide a film roll holding device that can suppress failures of film rolls by appropriately performing suppression treatment depending on the storage state of the film roll. shall be.

The above object of the present invention is achieved by the following means.

(1) A holding part that holds a film roll formed by winding a film around a core;
a rotation mechanism that rotates the film roll held by the holding section;
a measuring unit that measures a side surface of the film roll held by the holding unit to generate measurement data;
an analysis unit that generates an index value regarding voids between film layers by analyzing the measurement data;
an inhibition control unit that determines whether or not the change in the index value over time exceeds a determination threshold, and when it is determined that the change over time exceeds the determination threshold, causes the rotation mechanism to rotate the film roll by a predetermined amount;
A film roll holding device comprising:

(2) The film roll holding device according to (1), wherein the suppression control unit determines the change over time by comparing the index value at a past first timing with the index value at a current timing. .

(3) The film roll holding device according to (2) above, wherein the first timing is a timing immediately after production of the film roll.

(4) The first timing is the timing immediately after the production of the film roll, or the timing immediately after the rotation mechanism rotates the previous film roll,
The film roll holding device according to (2), wherein the suppression control unit repeatedly rotates the film roll by the rotation mechanism every time it is determined that the determination threshold value is exceeded.

(5) The measuring unit is an imaging device that photographs a side surface of the film roll as a photographing area,
The film roll holding device according to any one of (1) to (4) above, wherein the analysis unit generates the index value by analyzing image data generated by the imaging device.

(6) The film roll holding device according to (5) above, wherein the index value is a gap in the radial direction determined from the number of layers of the film included in a predetermined distance in the photographing area and the film thickness of the film. .

(7) The change over time is a reduction rate of the voids,
The film roll holding device according to (6) above, wherein the determination threshold value is any value in the range of 10 to 30%.

(8) The film according to any one of (1) to (4) above, wherein the measurement unit measures a side surface above the core among the side surfaces of the film roll held by the holding unit. Roll holding device.

(9) The holding unit holds the film roll in a state where the tape that joins the film to the core is located on the upper side of the core,
The film roll holding device according to (8), wherein the measuring section measures a side surface above the core among the side surfaces of the film roll held by the holding section.

(10) When the suppression control unit determines that the determination threshold is exceeded, the suppression control unit rotates the film roll by a predetermined angle within a range of 1 to 180 degrees in the winding direction or the opposite direction as the predetermined amount of rotation. The film roll holding device according to any one of (1) to (4) above, which is rotated.

(11) step (a) of generating measurement data by measuring the side surface of the film roll held by a holding unit that holds a film roll formed by winding a film around a core;
(b) generating an index value regarding voids between film layers by analyzing the measurement data;
determining whether or not the change over time of the index value exceeds the determination threshold, and when determining that the change over time exceeds the determination threshold, rotating the film roll held by the holding unit by a predetermined amount by a rotation mechanism ( c) and
A method for suppressing failure of a film roll that performs processing including.

(12)
A holding part that holds a film roll formed by winding a film around a core, a rotation mechanism that rotates the film roll held by the holding part, and a side surface of the film roll held by the holding part. A control program for controlling a film roll holding device comprising: a measurement unit that generates measurement data;
(a) measuring a side surface of the film roll held by the holding unit to generate measurement data;
(b) generating an index value regarding voids between film layers by analyzing the measurement data;
determining whether the change over time of the index value exceeds a determination threshold, and when determining that the change over time exceeds the determination threshold, rotating the film roll held by the holding unit by a predetermined amount by the rotation mechanism; (c) and
A control program that causes a computer to perform processes including

The film roll holding device according to the present invention includes a measurement unit that measures the side surface of the film roll held by the holding unit and generates measurement data, and generates an index value regarding gaps between film layers by analyzing the measurement data. and a suppression control section that determines whether or not the change over time of the index value exceeds a threshold value, and rotates the film roll by a predetermined amount using a rotation mechanism when it is determined that the change over time of the index value exceeds the threshold value. This can suppress failures in the film roll.

FIG. 1 is a diagram showing a schematic configuration of a film roll holding device according to the present embodiment. FIG. 2 is a block diagram of a film roll holding device. FIG. 3 is a perspective view showing the appearance of a held film roll. FIG. 2 is a cross-sectional view showing the configuration of an imaging unit. FIG. 1 is a schematic diagram showing the configuration of an imaging device including an imaging unit. FIG. 2 is a schematic diagram showing measurement points on a held film roll. It is a flowchart which shows failure suppression processing. It is a subroutine flowchart which shows index value calculation processing. FIG. 2 is a schematic diagram showing a method of manufacturing a film by a solution casting method. It is a schematic diagram of a film production line. It is a top view of a winding device. 11 is Table 1 showing evaluation results when different determination thresholds are applied in the suppression process. Table 2 shows evaluation results when different rotation amounts and rotation speeds are applied in the suppression process. Table 3 shows evaluation results when different rotation amounts are applied in the suppression process.

Hereinafter, embodiments of the present invention will be described with reference to the attached drawings. However, the scope of the invention is not limited to the disclosed embodiments. In addition, in the description of the drawings, the same elements are given the same reference numerals, and redundant description will be omitted. Furthermore, the dimensional ratios in the drawings are exaggerated for convenience of explanation and may differ from the actual ratios. In the drawings, the vertical direction is the Z direction, the direction along the rotation axis (core axis) of the film roll held by the film roll holding device is the Y direction, and the direction perpendicular to these Y and Z directions is the X direction. direction. In addition, the direction perpendicular to the rotation axis of the film roll is also referred to as the radial direction, lamination direction, or thickness direction.

FIG. 1 is a diagram showing a schematic configuration of a film roll holding device 1 according to the present embodiment. FIG. 2 is a block diagram showing the hardware configuration of the film holding device 1. As shown in FIG. FIG. 3 is a perspective view showing the appearance of the film roll 80 held by the film roll holding device 1.

(Film roll 80)
As shown in FIGS. 1 and 3, the film roll 80 is produced by winding a film 81 around a core 82 (also referred to as a winding core). The film 81 has a thickness in the range of 10 to 50 μm, for example, 40 μm. The width of the film 81 is within the range of 1300 to 3000 mm (1.3 to 3.0 m), for example 2200 mm. The total length of the film 81 wound around one film roll 80 (hereinafter referred to as the winding length) is 2000 m to 8000 m, for example, the winding length is 3900 m. The outer diameter of the film roll 80 is within the range of several hundred mm to 1 m.

At the point where the film 81 is wound around the core 82, a narrow double-sided tape 89 (see FIG. 3) with a width of several millimeters is attached to the core 82 along the axial direction (Y direction). This fixes (joins) the tip of the film 81 to the core 82. Further, the double-sided tape 89 may be slightly longer than the width of the film and protrude from the side edge of the film roll 80. Note that a marker using tape or ink may be applied to a position corresponding to the position of the double-sided tape on one side edge of the core 82 without extending the double-sided tape 89. FIG. 3 shows an initial state in which a film roll 80 immediately after manufacture is loaded and held in the film roll holding device 1. In this embodiment, in this initial state, the double-sided tape 89 (or marker) protruding from the end is used as a mark of the rotation angle, and the double-sided tape 89 is placed in the upward direction (Z direction). Alternatively, the rotational position of the film roll 80 may be detected using the position of the double-sided tape 89 as a mark, and the rotation amount and stop position may be controlled. In this case, the position of the double-sided tape 89 can be detected by arranging an optical sensor on the holding part 30. The initial state refers to the state in which the film roll 80 immediately after production is loaded and held in the film roll holding device 1, and before the failure suppression process of this embodiment (hereinafter simply referred to as suppression process) is performed. say. In the failure suppression process, the film roll 80 is rotated by a certain amount of angle at a constant speed. Note that at the tip of the film 81 at this starting point, there is a thickness equal to the overlap of the film 81 and the double-sided tape, and a step will be created between the tip and the point immediately before this. When the core 82 is rotated and the film 81 is wound, problems (failures) occur in the second and subsequent rolls due to deformation caused by this level difference (hereinafter referred to as tape transfer). In this embodiment, this tape transfer malfunction is also included in the malfunctions to be suppressed. The suppression process for preventing this failure and the improvement effect will be described later (FIGS. 7 and 8, which will be described later). Further, the materials and production method of this film roll 80 will also be described later (FIGS. 9 to 11, which will be described later).

[1] Film roll holding device 1
As shown in FIGS. 1 and 2, the film roll holding device 1 includes a control section 10, a storage section 20, a holding section 30, and an imaging device 40. The holding unit 30 holds and stores the film roll 80 for a long period of time. Further, the holding section 30 performs a failure prevention process of rotating the held film roll 80 around the rotation axis in response to a control signal from the control section 10 . The imaging device 40 functions as a measurement unit, measures the side surface of the film roll 80, and generates measurement data. The layer state of the film 81 of the film roll 80 can be observed from the side. The control unit 10 generates an index value regarding the gap between the film layers by analyzing the measurement data acquired from the measurement unit, that is, the image data acquired from the imaging device 40. Further, the timing for implementing failure suppression processing for the film roll 80 is determined according to the change in the index value over time, and the film roll 80 is rotated by controlling the holding unit 30 according to the determination.

(Indicator value)
Here, as the "index value" regarding the voids between film layers, "layer spacing", "average void distance", or "porosity" can be used. The “layer spacing” is the “layer spacing” (also referred to as layer pitch (spatial frequency)) in the radial direction of the film roll 80. The "average void distance" or "porosity" can be calculated using the "layer spacing" value and the average thickness value of the film. These "layer spacing,""average void distance (hereinafter also simply referred to as voids)," or "porosity" are generated by analyzing image data obtained from a film imaging device serving as a measurement unit. Specifically, the layer spacing is determined from the number of layers of the film 81 per unit distance. Further, the voids and the porosity can be calculated by measuring the number of layers of the film 81 per unit distance or the distance in the radial direction at a predetermined number of layers, and using this value and the average thickness of the film 81 using the following formula. Here, the average film thickness is measured in advance or is a product specification value, and is stored in the storage unit 20 in advance.
Voids (average gap distance) = (radial length of n layers - average film thickness x number of layers n) / number of layers n
Porosity = (average pore distance/radial length per layer)
For example, if n=100 layers are used, and the film 81 has an average thickness of 0.04 mm (40 μm), the length in the thickness direction (hereinafter also referred to as the radial direction) of the 100 layers when wound as the film roll 80 is is 4.1 mm. In this case, the gap is 1.0 μm (=(4.1−(0.04×100)/100)). Similarly, the porosity can be calculated by dividing the porosity by the film thickness. For example, in the same numerical example, the porosity is 1.0/41.0=2.44%. In this embodiment described below, "void" is used as the index value unless otherwise mentioned.

Note that other measuring devices may be used instead of the imaging device as the measuring device that obtains the measurement data that is the basis for generating the index value. For example, the unevenness of the side surface is measured by a contact type surface roughness measuring device using a probe or the like or a non-contact surface roughness measuring device using a laser beam, and the layer pitch etc. can be calculated from the period.

[1.1] Control unit 10
The control unit 10 has a CPU and a memory. The CPU is a control circuit composed of a multi-core processor and the like that controls the above-mentioned parts and executes various arithmetic processing according to a program. Each function of the film roll holding device 1 is performed by the CPU executing a corresponding program. Memory is a fast-accessible main storage device that temporarily stores programs and data as a work area. For example, DRAM, SDRAM, SRAM, etc. are employed as the memory.

[1.2] Storage unit 20
The storage unit 20 is a large-capacity auxiliary storage device that stores various programs including an operating system and various data. For example, a hard disk, solid state drive, flash memory, ROM, etc. are used as the storage. The storage unit 20 also stores film thickness information (product specifications or actual measurement values) of the film 81 constituting the film roll 80 that is the target of the suppression process, and an index value generated at a predetermined first timing. The first timing may be, for example, immediately after production of the film roll 80 (immediately after winding up during production), or when the film roll 80 is subjected to repeated restraint processing, the same film immediately before This is immediately after rotation with respect to the roll 80.

[1.3] Control unit 10
The control unit 10 functions as an analysis unit 11, a change amount calculation unit 12, and a suppression control unit 13. The analysis unit 11 measures the number of film layers per unit length in the radial direction, or the distance in the radial direction with a predetermined number of layers, by performing image analysis on the image data acquired from the imaging device 40. As an image analysis, the analysis unit 11 calculates the number of film layers by, for example, performing edge enhancement processing on the image data and measuring the cycle of image density in the radial direction. The analysis unit 11 generates one of the above index values based on the number of film layers or the number of film layers and (known) film thickness information of the film 81. The index value generated by the analysis section 11 is stored in the storage section 20 or passed to the change amount calculation section 12 together with timing information. The timing information here refers to information indicating that it is immediately after production, and/or date and time information when the side surface of the film roll 80 was measured by a measuring device (for example, the date and time of photographing by the imaging device 40).

The change calculation unit 12 calculates the index value at the first timing stored in the storage unit 20 and the index value at the current timing (also referred to as the second timing) acquired from the analysis unit 11 (hereinafter referred to as the current index value). ) to calculate changes over time. For example, as the index value at the first timing acquired from the storage unit 20, the amount of change (A1-A2) in the current index value (A2) compared to the index value (A1) immediately after the film roll 80 is generated, or The rate of change (1-A2/A1) is calculated as the change over time. For example, when using voids (average voids) as the index value, if the index value changes from 1.0 μm at the first timing to 0.8 μm at the second timing, the rate of change is It becomes 20% (=1-0.8/1.0).

The suppression control unit 13 determines whether or not to perform the suppression process based on the change over time sent from the change amount calculation unit 12, and based on the determination result, sends a control signal to the holding unit 30 to control the rotation of the film roll 80. or have them do something. Further, a control signal is sent to the imaging device 40 at a predetermined timing according to a predetermined observation period (for example, every few hours or every day) to cause the side surface of the film roll 80 to be measured.

[1.4] Holding part 30
As shown in FIG. 1 and the like, the holding section 30 includes a rotation mechanism 31 and a housing 32. The housing 32 includes a front panel 32f and a rear panel 32r that face each other. In a state where the film roll 80 is held by the holding part 30, the film roll 80 is rotatably held by the holding part 30 via bearings b1 attached to the tips of both panels 32f and 32r. Rotation mechanism 31 includes a motor 311, a drive shaft 312 non-rotatably engaged with core 82, and a plurality of gear trains. When the motor 311 is driven, the entire film roll 80 rotates together with the drive shaft 312. The rotation direction is set to be the same as the winding direction or the opposite direction, more preferably the same as the winding direction, and the rotation speed and rotation amount (rotation time) at this time are controlled by control signals from the control unit 10. be done. For example, the rotation mechanism 31 of the holding unit 30 rotates the film roll 80 at a very slow rotation speed of 1 degree/1 min within a range of 1 to 360 degrees, more preferably 1 degree in one suppression process. Rotate by a predetermined angle within the range of ~180 degrees. For example, it is controlled to rotate by 90 degrees or 180 degrees in the winding direction.

[1.5] Imaging device 40
The imaging device 40 will be described below with reference to FIG. 2 and FIGS. 4 to 6. The imaging device 40 includes an imaging unit 41 and a movement mechanism 45. FIG. 4 is a cross-sectional view showing the configuration of the imaging unit 41. As shown in FIG. FIG. 5 is a schematic diagram showing the overall configuration of the imaging device 40. FIG. 6 is a schematic diagram showing measurement points p01 to p03 and p11 to p13 (also referred to as photographing points) on the side surface s1 of the held film roll 80.

(Imaging unit 41)
As shown in FIG. 4, the imaging unit 41 includes an imaging element 411, a telecentric lens 412, a half mirror 413, an illumination 414, a total reflection mirror 415, and a housing 419 that houses these as a whole. The opening w1 provided in the housing 419 is made of a transparent plate that transmits light. The imaging unit 41 photographs the side surface s1 of the film roll 80 and generates image data. The image sensor 411 is a CCD or a CMOS. The image sensor 411 is a two-dimensional sensor composed of, for example, CMOS monochrome 2K×2K pixels or 4K×4K pixels. As another example, the image sensor 411 may be configured with a one-dimensional line sensor with monochrome 8K pixels. In this case, the orientation of the imaging unit 41 is adjusted so that the direction in which the pixels of the CMOS are lined up is along the radial direction of the measurement point (p01, etc.) to be photographed by the rotation function of the moving mechanism 45 (not shown). The telecentric lens 412 is, for example, a lens with a magnification of 1 to 3 times, for example 2 times, and a WD of 50 to 150 mm, for example 65 mm. By using a telecentric lens, even if the distance between the imaging unit 41 and the measurement location (side surface s1 of the film roll 80) changes, the effect on the image size is reduced. The illumination 414 is composed of an LED, and is white illumination or white line illumination whose light emitting surface is the long axis along the line of line sensors. The imaging unit 41 obtains image data by photographing the side surface of the film roll 80 in an imaging field of view in a range of 10 to 50 mm along the radial direction, for example, a length of 14 mm, at a resolution of 4000 pixels. In this case, the pixel resolution is 3.5 μm, which is sufficient for the thickness of the film 81 of several tens of μm (for example, 40 μm). Alternatively, if the image sensor 411 is an 8K pixel line sensor and a telecentric lens 412 with a magnification of 1x is used, image data obtained by photographing a 28 mm long imaging field with a resolution of 8000 pixels is obtained. In this case as well, the pixel resolution is 3.5 μm. Note that by selecting the lens magnification and the number of pixels of the image sensor, it may be configured to have a higher pixel resolution of 1 μm or less.

(Moving mechanism 45)
The moving mechanism 45 moves the imaging unit 41 to an arbitrary position within the XZ plane depending on the location to be photographed. The moving mechanism 45 includes a bottom plate 451, a motor 452, a horizontal rail 453, a horizontal slide pedestal 454, a vertical rail 455, a vertical slide pedestal 456, a support member 457 that supports the imaging unit 41, and a motor 458. The horizontal slide pedestal 454 includes a bottom portion 5a, a pedestal 5b, and a pillar 5c that are slidably connected to the horizontal rail 453 in the X direction. The pillar 5c fixedly supports the upper and lower rails 455. The vertical rail 455 connects the vertical sliding pedestal 456 so as to be slidable in the Z direction. The vertically sliding pedestal 456 fixedly supports the support member 457 and the imaging unit 41 connected thereto. The horizontal slide pedestal 454 and the vertical slide pedestal 456 are moved in the X direction and Z direction by motors 452 and 458, respectively (directions of arrows A and B in FIG. 5). Thereby, the imaging unit 41 is moved to an arbitrary position within the XZ plane.

FIG. 6 is a diagram showing a photographing location on the side surface s1 of the film roll 80. The imaging unit 41 is moved by the moving mechanism 45 to perform imaging at a plurality of imaging locations. The photographing points are photographing points p01 to p03 arranged above the core 82, more precisely, directly above the core 82 (indicated by 0 degrees in FIG. 6). Furthermore, photographing points p11 to p13 arranged in a 90 degree direction (horizontal direction) may be added to this. When the outer circumferential surface of the innermost film 81, that is, the core 82, is 0%, and the outer circumferential surface of the outermost film 81, that is, the film roll 80, is 100%, the (centers of) photographed points p01, p02, and p03 are true. The positions are 20%, 50%, and 80% in the upward direction, respectively. Similarly, the shooting locations p11, p12, and p13 are at 20%, 50%, and 80% positions, respectively, in the horizontal direction. In this embodiment, the average value of index values obtained by analyzing six image data obtained by photographing six locations p01 to p03 and p11 to p13, or The average value of the three or any index value can be used. In the following description, it is assumed that the average value of the index values at three locations (p01 to p03) in the directly upward direction (upper side surface) is used.

FIG. 6 shows the film roll 80 placed in its initial state. In the initial state, the rotation position is adjusted so that the double-sided tape 89 is on top. As shown in FIG. 6, the film roll 80 held by the holding part 30 is rotated by the rotation mechanism 31 clockwise when viewed from the Y direction (indicated by an arrow). Further, in the following, the directly upward direction in the initial state is assumed to be 0 degrees, and the clockwise direction is assumed to be the positive direction (positive angle). In the suppression process by one rotation, rotation is performed by only 90 degrees or 180 degrees at a constant speed (this suppression process may be repeated multiple times).

[1.6] Operation panel 50
The operation panel 50 includes a touch panel, a numeric keypad, a start button, a stop button, etc., and is used to display various information and input various instructions. Through the operation panel 50, the user can set the execution period of the suppression process and input an end instruction. Further, it may be possible to set conditions such as a determination threshold value, rotation amount, rotation speed, etc. in the following failure suppression process.

[1.7] Failure Suppression Process The film roll failure suppression process (hereinafter also simply referred to as suppression process) will be described below with reference to FIGS. 7 and 8. FIG. 7 is a flowchart showing the failure suppression process. FIG. 8 is a subroutine flowchart showing the index value calculation process performed in FIG.

(Step S01)
The produced film roll 80 is held in the holding section 30. A method for producing this film roll 80 will be described later (see FIGS. 9 to 11, which will be described later). The film roll 80 held here is immediately after production, more specifically, immediately after the film 81 is wound around the core 82 to produce the film roll 80.

(Step S02)
The film roll holding device 1 performs index value calculation processing. The processing here is shown in the subroutine flowchart of FIG. The index value calculation process performed in step S02 is performed at the first timing. When the process of step S02 is performed subsequent to step S01, the first timing is the timing immediately after production (immediately after production winding). On the other hand, if the process in step S02 is performed via step S09 (encircled number 20), the timing is immediately after the suppression operation in step S08 is executed.

(Steps S201, S202)
The control unit 10 sends a control signal to the imaging device 40 to move the imaging unit 41 and perform imaging. By moving and photographing, image data of a measurement location (for example, measurement location p01 (see FIG. 6)) on the side surface s1 of the film roll 80 is obtained.

(Step S203)
If the imaging of all locations has not been completed (NO), the process from step S201 onward is repeated, and the next measurement locations (for example, measurement locations p02 and p03) are captured to obtain image data at each measurement location.

(Step S204)
The analysis unit 11 analyzes the image and calculates an index value. For example, each of the three image data obtained by photographing the three measurement points p01, p02, and p03 is analyzed to determine the air gap in the radial direction. Then, by averaging these three voids, a void (average void) as an index value is obtained. With this, the process in FIG. 8 is completed, and the process returns to step S03 and subsequent steps in FIG.

(Step S03)
Here, the control unit 10 stores the index value obtained in step S204 in the storage unit 20.

(Step S04)
If it is the suppression operation determination timing (YES), the control unit 10 advances the process to step S05. The determination timing is set in advance, and is, for example, every half day (12 hours) or every day (24 hours).

(Step S05)
Here, the film roll holding device 1 performs index value calculation processing. This process is the same as step S02, except that the timing of calculating the index value is different, and is the process shown in the subroutine flowchart of FIG. 8. In the following, the current timing at which the calculation process of step S05 is performed will also be referred to as a second timing.

(Step S06)
The change amount calculation unit 12 compares the index value at the second timing obtained in step S05 with the index value at the first timing read from the storage unit 20, and calculates the change over time. The change over time is, for example, a rate of change. For example, by dividing the index value x2 at the current second timing by the index value x1 at the past first timing, the rate of change (=1-x2/x1) as a change over time is calculated.

(Step S07)
Here, the suppression control unit 13 determines whether the change over time is larger than a predetermined threshold. For example, the threshold value is any value in the range of 10 to 30%, preferably 20%, and more preferably 15%. For example, if the gap is 1 μm at the initial stage (first timing) and decreases to 0.8 μm at the second timing, the rate of change will be 20%, exceeding the threshold of 15%. . If the change over time exceeds the threshold (YES), the process proceeds to step S08, and if it does not exceed the threshold (NO), the process returns to step S04 (the circled number 10).

(Step S08)
The suppression control unit 13 sends a control signal to the holding unit 30, and causes the rotation mechanism 31 to rotate the film roll 80 by a predetermined rotation angle within a range of ±180 degrees (excluding 0 degrees) at a constant rotation speed. . The rotation speed is a constant speed within the range of 1 to 5 degrees/min. If the rotation speed is faster than 5 degrees/min, winding misalignment may occur, and if it is slower than 1 degree/min, it takes too much time to rotate. The winding misalignment here means a failure in which the film shifts in the width direction due to weak winding tension or excessive air entrainment. Furthermore, the direction of rotation is preferably the winding direction (ie, +1 to +180 degrees (clockwise in FIG. 6)) from the viewpoint of winding misalignment. The angle is preferably in the range of +90 to +180 degrees, more preferably +180 degrees (half a turn in the winding direction). In this step S08, for example, in one suppression process, the rotation is performed by +180 degrees at a rotation speed of 1 degree/min over a period of 3 hours.

(Step S09)
If it is to be repeated, the control unit 10 does not end the process (NO) and repeats the process from step S02 onwards (the circled number 20). On the other hand, if termination conditions are met (YES), such as when a termination instruction is received from the operation panel 50 or the like used by the user, or when a predetermined execution period has elapsed, the process is terminated (END). .

As described above, the film roll holding device 1 according to the present embodiment includes a measurement section that measures the side surface of the film roll held by the holding section and generates measurement data, and a measurement section that generates measurement data by analyzing the measurement data. An analysis unit that generates an index value regarding voids, and a suppression control unit that determines whether the change in index value over time exceeds a threshold value, and when it is determined that the change in index value exceeds the threshold value, rotates the film roll by a predetermined amount using a rotation mechanism. and. This can prevent failures in the film roll.

(Production (manufacturing) of film roll in this embodiment)
[2] Film roll 80 (hereinafter also simply referred to as film roll)
[2.1] Thermoplastic Resin The thermoplastic resin material used for the film according to this embodiment is not limited as long as it can be handled as a film roll after film formation. For example, thermoplastic resins used for polarizing plates include cellulose ester resins such as triacetylcellulose (TAC), cellulose acetate propionate (CAP), and diacetylcellulose (DAC), and cycloolefin polymers (COP). Cyclic olefin resins such as (hereinafter also referred to as cycloolefin resins), polypropylene resins such as polypropylene (PP), acrylic resins such as polymethyl methacrylate (PMMA), and polyethylene terephthalate (PET). Polyester resin can be used.

In particular, in a film with a low elastic modulus, for example, a resin with less than 3.0 GPa, winding misalignment is likely to occur when forming a film roll, so the following relational expressions (1) and (2) according to the present embodiment are satisfied. It is preferable to control the coefficient of static friction as follows.
The knurling part is part A, the part on the back side of the film opposite to part A is part B, the surface of the film that has not been knurled other than part A and part B is part C, and part A and part B are When the static friction coefficients of are respectively a and b,
Relational expression (1) Static friction coefficient between surfaces C<Static friction coefficient between parts A and B Relational expression (2) a<b
Controlling the coefficient of static friction in this way is effective when applied to film rolls using cycloolefin polymer (COP) or polymethyl methacrylate (PMMA), which are films with a low elastic modulus, as thermoplastic resins. .

Furthermore, the effects of this embodiment are more valuable in the thin film region. The thickness of the thin film is preferably 5 to 80 μm, more preferably 10 to 50 μm, and even more preferably 10 to 45 μm. When the film thickness is less than 10 μm, the rigidity of the film roll is low and it is difficult to maintain the roll shape. If the film thickness exceeds 80 μm, the mass increases, making it difficult to produce a long film roll.

[2.1.1] Cycloolefin resin The cycloolefin resin contained in the film roll of this embodiment is a polymer of cycloolefin monomers, or a copolymerizable monomer of cycloolefin monomers and other monomers. A copolymer with a polymer is preferable.

The cycloolefin monomer is preferably a cycloolefin monomer having a norbornene skeleton, and a cycloolefin monomer having a structure represented by the following general formula (A-1) or (A-2). It is more preferable that there be.

In general formula (A-1), R ¹ to R ⁴ each independently represent a hydrogen atom, a hydrocarbon group having 1 to 30 carbon atoms, or a polar group. p represents an integer from 0 to 2. However, R ¹ to R ⁴ do not all represent hydrogen atoms at the same time, R ¹ and R ² do not represent hydrogen atoms at the same time, and R ³ and R ⁴ do not represent hydrogen atoms at the same time. do.

In the general formula (A-1), the hydrocarbon group having 1 to 30 carbon atoms represented by R ¹ to R ⁴ is preferably a hydrocarbon group having 1 to 10 carbon atoms; More preferably, it is a hydrocarbon group of number 1 to 5. The hydrocarbon group having 1 to 30 carbon atoms may further have a linking group containing, for example, a halogen atom, an oxygen atom, a nitrogen atom, a sulfur atom or a silicon atom. Examples of such linking groups include divalent polar groups such as carbonyl groups, imino groups, ether bonds, silyl ether bonds, and thioether bonds. Examples of hydrocarbon groups having 1 to 30 carbon atoms include methyl, ethyl, propyl, butyl, and the like.

Examples of the polar groups represented by R ¹ to R ⁴ in general formula (A-1) include a carboxy group, a hydroxy group, an alkoxy group, an alkoxycarbonyl group, an aryloxycarbonyl group, an amino group, an amide group, and a cyano group. is included. Among these, a carboxy group, a hydroxy group, an alkoxycarbonyl group, and an aryloxycarbonyl group are preferable, and from the viewpoint of ensuring solubility during solution film formation, an alkoxycarbonyl group and an aryloxycarbonyl group are preferable.

In general formula (A-1), p is preferably 1 or 2 from the viewpoint of increasing the heat resistance of the optical film. This is because when p is 1 or 2, the obtained polymer becomes bulky and the glass transition temperature tends to increase.

In the general formula (A-2), R ⁵ represents a hydrogen atom, a hydrocarbon group having 1 to 5 carbon atoms, or an alkylsilyl group having an alkyl group having 1 to 5 carbon atoms. R ⁶ represents a carboxyl group, a hydroxy group, an alkoxycarbonyl group, an aryloxycarbonyl group, an amino group, an amide group, a cyano group, or a halogen atom (fluorine atom, chlorine atom, bromine atom, or iodine atom). p represents an integer from 0 to 2.

R ⁵ in the general formula (A-2) preferably represents a hydrocarbon group having 1 to 5 carbon atoms, more preferably a hydrocarbon group having 1 to 3 carbon atoms.

R ⁶ in the general formula (A-2) preferably represents a carboxyl group, a hydroxy group, an alkoxycarbonyl group, or an aryloxycarbonyl group. More preferred is an oxycarbonyl group.

In general formula (A-2), p preferably represents 1 or 2 from the viewpoint of increasing the heat resistance of the optical film. This is because when p represents 1 or 2, the obtained polymer becomes bulky and the glass transition temperature tends to increase.

A cycloolefin monomer having a structure represented by general formula (A-2) is preferred from the viewpoint of improving solubility in organic solvents. Generally, the crystallinity of organic compounds decreases by breaking the symmetry, so the solubility in organic solvents improves. Since R ⁵ and R ⁶ in the general formula (A-2) are substituted only on the ring-constituting carbon atoms on one side with respect to the symmetry axis of the molecule, the symmetry of the molecule is low, that is, the general formula (A- Since the cycloolefin monomer having the structure represented by 2) has high solubility, it is suitable for producing an optical film by a solution casting method.

The content ratio of the cycloolefin monomer having the structure represented by general formula (A-2) in the cycloolefin monomer polymer is relative to the total of all cycloolefin monomers constituting the cycloolefin resin. For example, it may be 70 mol% or more, preferably 80 mol% or more, and more preferably 100 mol%. When a certain amount or more of a cycloolefin monomer having a structure represented by general formula (A-2) is contained, the orientation of the resin increases, so that the retardation value tends to increase.

Specific examples of cycloolefin monomers having a structure represented by general formula (A-1) are shown below in Exemplary Compounds 1 to 14, and cycloolefin monomers having a structure represented by general formula (A-2) are shown below. Specific examples of the mer are shown in Exemplary Compounds 15 to 34.

Examples of copolymerizable monomers that can be copolymerized with cycloolefin monomers include copolymerizable monomers that can be ring-opening copolymerized with cycloolefin monomers, and addition copolymerizable monomers that can be copolymerized with cycloolefin monomers. Possible copolymerizable monomers and the like are included.

Examples of copolymerizable monomers capable of ring-opening copolymerization include cycloolefins such as cyclobutene, cyclopentene, cycloheptene, cyclooctene, and dicyclopentadiene.

Examples of copolymerizable monomers capable of addition copolymerization include unsaturated double bond-containing compounds, vinyl cyclic hydrocarbon monomers, (meth)acrylates, and the like. Examples of unsaturated double bond-containing compounds include olefinic compounds having 2 to 12 carbon atoms (preferably 2 to 8 carbon atoms), such as ethylene, propylene, butene, and the like. Examples of vinyl cyclic hydrocarbon monomers include vinyl cyclopentene monomers such as 4-vinylcyclopentene and 2-methyl-4-isopropenylcyclopentene. Examples of (meth)acrylates include alkyl (meth)acrylates having 1 to 20 carbon atoms such as methyl (meth)acrylate, 2-ethylhexyl (meth)acrylate and cyclohexyl (meth)acrylate.

The content of the cycloolefin monomer in the copolymer of the cycloolefin monomer and the copolymerizable monomer is, for example, 20 to 80 mol%, based on the total of all monomers constituting the copolymer. Preferably, it may be 30 to 70 mol%.

As mentioned above, the cycloolefin resin is produced by polymerizing or It is a polymer obtained by copolymerization, and examples thereof include the following.

(1) Ring-opening polymer of cycloolefin monomer (2) Ring-opening copolymer of cycloolefin monomer and copolymerizable monomer capable of ring-opening copolymerization with it (3) Above (1) or a hydrogenated product of the ring-opened (co)polymer of (2) (4) The ring-opened (co)polymer of (1) or (2) above is cyclized by a Friedel-Crafts reaction, and then hydrogenated ( Co) Polymer (5) Saturated copolymer of a cycloolefin monomer and an unsaturated double bond-containing compound (6) Addition copolymer of a cycloolefin monomer and a vinyl cyclic hydrocarbon monomer and its hydrogenated product (7) Alternating copolymer of cycloolefin monomer and (meth)acrylate The polymers of (1) to (7) above can be prepared by known methods, for example, JP-A-2008- It can be obtained by the method described in JP-A No. 107534 and JP-A-2005-227606. For example, as the catalyst and solvent used in the ring-opening copolymerization in (2) above, those described in paragraphs 0019 to 0024 of JP-A No. 2008-107534 can be used. As the catalyst used for the hydrogenation in (3) and (6) above, for example, those described in paragraphs 0025 to 0028 of JP-A No. 2008-107534 can be used. As the acidic compound used in the Friedel-Crafts reaction in (4) above, for example, those described in paragraph 0029 of JP-A No. 2008-107534 can be used. As the catalyst used in the addition polymerizations of (5) to (7) above, for example, those described in paragraphs 0058 to 0063 of JP-A No. 2005-227606 can be used. The alternating copolymerization reaction (7) above can be carried out, for example, by the method described in paragraphs 0071 and 0072 of JP-A No. 2005-227606.

Among these, the polymers (1) to (3) and (5) above are preferred, and the polymers (3) and (5) above are more preferred. In other words, the cycloolefin resin has a structural unit represented by the following general formula (B-1) and a structural unit represented by the following general formula (B-1) in that the resulting cycloolefin resin can have a high glass transition temperature and a high light transmittance. It is preferable to contain at least one of the structural units represented by the following general formula (B-2), only contain the structural unit represented by the general formula (B-2), or contain the structural unit represented by the general formula (B-1). It is more preferable to include both the structural unit represented by the formula (B-2) and the structural unit represented by the general formula (B-2). The structural unit represented by the general formula (B-1) is a structural unit derived from the cycloolefin monomer represented by the above-mentioned general formula (A-1), and is represented by the general formula (B-2). The structural unit represented by the above-mentioned general formula (A-2) is a structural unit derived from a cycloolefin monomer.

In general formula (B-1), X represents -CH=CH- or -CH ₂ CH ₂ -. R ¹ to R ⁴ and p have the same meanings as R ¹ to R ⁴ and p in general formula (A-1), respectively.

In general formula (B-2), X represents -CH=CH- or -CH ₂ CH ₂ -. R ⁵ to R ⁶ and p have the same meanings as R ⁵ to R ⁶ and p in general formula (A-2), respectively.

The cycloolefin resin according to this embodiment may be a commercially available product. Examples of commercially available cycloolefin resins include Arton G (for example, G7810, etc.), Arton F, Arton R (for example, R4500, R4900, and R5000, etc.) manufactured by JSR Corporation, and Arton RX. included.

The intrinsic viscosity [η] inh of the cycloolefin resin is preferably 0.2 to 5 cm 3 /g, more preferably 0.3 to 3 cm 3 /g, and 0.4 cm ³ /g when measured at 30°C. It is more preferably 1.5 cm ³ /g.

The number average molecular weight (Mn) of the cycloolefin resin is preferably 8,000 to 100,000, more preferably 10,000 to 80,000, and even more preferably 12,000 to 50,000. The weight average molecular weight (Mw) of the cycloolefin resin is preferably 20,000 to 300,000, more preferably 30,000 to 250,000, and even more preferably 40,000 to 200,000. The number average molecular weight and weight average molecular weight of the cycloolefin resin can be measured in terms of polystyrene using gel permeation chromatography (GPC).

<Gel permeation chromatography>
Solvent: Methylene chloride Column: Shodex K806, K805, K803G (3 units manufactured by Showa Denko K.K. were connected and used)
Column temperature: 25℃
Sample concentration: 0.1% by mass
Detector: RI Model 504 (manufactured by GL Science)
Pump: L6000 (manufactured by Hitachi, Ltd.)
Flow rate: 1.0ml/min
Calibration curve: A calibration curve using 13 samples of standard polystyrene STK standard polystyrene (manufactured by Tosoh Corporation) within the range of Mw=500 to 2,800,000 was used. The 13 samples are preferably used at approximately equal intervals.

When the intrinsic viscosity [η] inh, number average molecular weight, and weight average molecular weight are within the above ranges, the cycloolefin resin has good heat resistance, water resistance, chemical resistance, mechanical properties, and moldability as a film. Become.

The glass transition temperature (Tg) of the cycloolefin resin is usually 110°C or higher, preferably 110 to 350°C, more preferably 120 to 250°C, and preferably 120 to 220°C. More preferred. When Tg is 110°C or higher, deformation under high temperature conditions can be easily suppressed. On the other hand, when Tg is 350° C. or less, molding becomes easy and deterioration of the resin due to heat during molding is easily suppressed.

The content of the cycloolefin resin is preferably 70% by mass or more, more preferably 80% by mass or more based on the film.

[2.1.2] Acrylic Resin The acrylic resin according to the present embodiment is a polymer of acrylic ester or methacrylic ester, and also includes copolymers with other monomers.

Therefore, the acrylic resin according to this embodiment also includes methacrylic resin. The resin is not particularly limited, but it consists of methyl methacrylate units in the range of 50 to 99% by mass and other monomer units copolymerizable with this in the range of 1 to 50% by mass. is preferred.

Other units constituting the acrylic resin formed by copolymerization include alkyl methacrylates having an alkyl number of 2 to 18 carbon atoms, alkyl acrylates having an alkyl number of 1 to 18 carbon atoms, isobornyl methacrylate, 2- Hydroxyalkyl acrylates such as hydroxyethyl acrylate, α,β-unsaturated acids such as acrylic acid and methacrylic acid, acrylamides such as acryloylmorpholine and N-hydroxyphenylmethacrylamide, N-vinylpyrrolidone, maleic acid, fumaric acid, itaconic acid, etc. unsaturated group-containing dicarboxylic acids, aromatic vinyl compounds such as styrene and α-methylstyrene, α, β-unsaturated nitriles such as acrylonitrile and methacrylonitrile, maleic anhydride, maleimide, N-substituted maleimide, and glutaric acid. Examples include imide and glutaric anhydride.

Examples of copolymerizable monomers forming units excluding glutarimide and glutaric anhydride from the above units include monomers corresponding to the above units. That is, alkyl methacrylates having an alkyl number of 2 to 18 carbon atoms, alkyl acrylates having an alkyl number of 1 to 18 carbon atoms, hydroxyalkyl acrylates such as isobornyl methacrylate, 2-hydroxyethyl acrylate, acrylic acid, methacrylic acid, etc. α,β-unsaturated acids, acryloylmorpholine, acrylamide such as N-hydroxyphenylmethacrylamide, N-vinylpyrrolidone, unsaturated group-containing dicarboxylic acids such as maleic acid, fumaric acid, itaconic acid, styrene, α-methylstyrene monomers such as aromatic vinyl compounds such as, α,β-unsaturated nitriles such as acrylonitrile and methacrylonitrile, maleic anhydride, maleimide, and N-substituted maleimide.

Further, the glutarimide unit can be formed, for example, by reacting an intermediate polymer having a (meth)acrylic acid ester unit with a primary amine (imidizing agent) to imidize it (see JP-A No. 2011-26563). ).

The glutaric anhydride unit can be formed, for example, by heating an intermediate polymer having (meth)acrylic acid ester units (see Japanese Patent No. 4961164).

Among the above structural units, the acrylic resin according to this embodiment includes isobornyl methacrylate, acryloylmorpholine, N-hydroxyphenylmethacrylamide, N-vinylpyrrolidone, styrene, hydroxyethyl methacrylate, Particular preference is given to the inclusion of maleic anhydride, maleimide, N-substituted maleimide, glutaric anhydride or glutarimide.

The acrylic resin according to the present embodiment has the following advantages: from the viewpoint of controlling dimensional changes due to changes in environmental temperature and humidity, peelability from metal supports during film production, drying properties of organic solvents, heat resistance, and mechanical strength. From the viewpoint of improvement of It is particularly preferable that

If it is 50,000 or more, it has excellent heat resistance and mechanical strength, and if it is 1,000,000 or less, it has excellent releasability from a metal support and drying property of an organic solvent.

The method for producing the acrylic resin according to this embodiment is not particularly limited, and any known method such as suspension polymerization, emulsion polymerization, bulk polymerization, or solution polymerization may be used. Here, as the polymerization initiator, ordinary peroxide-based and azo-based ones can be used, and redox-based ones can also be used. Regarding the polymerization temperature, suspension or emulsion polymerization can be carried out within the range of 30 to 100°C, and bulk or solution polymerization can be carried out within the range of 80 to 160°C. In order to control the reduced viscosity of the obtained copolymer, polymerization can also be carried out using an alkyl mercaptan or the like as a chain transfer agent.

The glass transition temperature Tg of the acrylic resin is preferably within the range of 80 to 120°C from the viewpoint of maintaining the mechanical strength of the film.

Commercially available acrylic resins can also be used as the acrylic resin according to this embodiment. For example, Delpet 60N, 80N, 980N, SR8200 (manufactured by Asahi Kasei Chemicals), Dianal BR52, BR80, BR83, BR85, BR88, EMB-143, EMB-159, EMB-160, EMB-161, Examples include EMB-218, EMB-229, EMB-270, EMB-273 (manufactured by Mitsubishi Rayon Co., Ltd.), KT75, TX400S, and IPX012 (all manufactured by Denki Kagaku Kogyo Co., Ltd.). Two or more types of acrylic resins can also be used in combination.

The acrylic resin according to the present embodiment preferably contains an additive. As an example of the additive, acrylic particles (rubber elastic particles) described in International Publication No. 2010/001668 can be used to It is preferable to include it in order to improve strength and adjust the rate of dimensional change. Examples of commercially available multilayered acrylic granular composites include "Metablen W-341" manufactured by Mitsubishi Rayon, "Kane Ace" manufactured by Kaneka, "Paraloid" manufactured by Kureha, and Roam & Examples include "Acryloid" manufactured by Haas, "Stafyloid" manufactured by Aica, Chemisnow MR-2G, MS-300X (manufactured by Soken Kagaku Co., Ltd.), and "Parapet SA" manufactured by Kuraray. can be used alone or in combination of two or more.

The volume average particle diameter of the acrylic particles is 0.35 μm or less, preferably 0.01 to 0.35 μm, and more preferably 0.05 to 0.30 μm. If the particle size is above a certain level, the film can be easily stretched under heating, and if the particle size is below a certain level, the transparency of the obtained film is unlikely to be impaired.

From the viewpoint of flexibility, the film according to this embodiment preferably has a flexural modulus (JIS K7171) of 1500 MPa or less. This bending elastic modulus is more preferably 1300 MPa or less, still more preferably 1200 MPa or less. The bending elastic modulus varies depending on the type and amount of the acrylic resin and rubber elastic particles in the film, and for example, the larger the content of rubber elastic particles, the lower the bending elastic modulus. Furthermore, the flexural modulus is generally smaller when a copolymer of an alkyl methacrylate and an alkyl acrylate is used as the acrylic resin than when a homopolymer of an alkyl methacrylate is used.

[2.1.3] Cellulose ester resin In the film roll of this embodiment, it is also preferable to use a cellulose ester resin.

The cellulose ester used in this embodiment refers to a portion of the hydrogen atoms of the 2-, 3-, and 6-position hydroxy groups (-OH) in the β-1,4-bonded glucose unit constituting cellulose, or A cellulose acylate resin completely substituted with acyl groups.

The cellulose ester used is not particularly limited, but it is preferably an ester of a linear or branched carboxylic acid having about 2 to 22 carbon atoms. The carboxylic acid constituting the ester may be an aliphatic carboxylic acid, may form a ring, or may be an aromatic carboxylic acid. For example, if the hydrogen atom in the hydroxyl group of cellulose is an acyl group having 2 to 22 carbon atoms such as acetyl group, propionyl group, butyryl group, isobutyryl group, valeryl group, pivaloyl group, hexanoyl group, octanoyl group, lauroyl group, stearoyl group, etc. Examples include cellulose esters substituted with . The carboxylic acid (acyl group) constituting the ester may have a substituent. The carboxylic acid constituting the ester is preferably a lower fatty acid having 6 or less carbon atoms, and more preferably a lower fatty acid having 3 or less carbon atoms. Note that the acyl group in the cellulose ester may be a single type or a combination of a plurality of acyl groups.

Specific examples of preferred cellulose esters include cellulose acetates such as diacetylcellulose (DAC) and triacetylcellulose (TAC), as well as cellulose acetate propionate (CAP), cellulose acetate butyrate, and cellulose acetate propionate butyrate. Examples include mixed fatty acid esters of cellulose to which a propionate group or a butyrate group is bonded in addition to the acetyl group. These cellulose esters may be used alone or in combination.

(Type of acyl group/degree of substitution)
By adjusting the type and degree of substitution of the acyl group of the cellulose ester, the humidity fluctuation of the phase difference can be controlled within a desired range, and the uniformity of the film thickness can be improved.

The smaller the degree of substitution of the acyl group of the cellulose ester, the better the retardation development property becomes, making it possible to form a thin film. On the other hand, if the degree of substitution of the acyl group is too small, durability may deteriorate, which is not preferable.

On the other hand, the higher the degree of substitution of the acyl group in the cellulose ester, the less the retardation will appear, so it is necessary to increase the stretching ratio during film formation, but it is difficult to stretch uniformly at a high stretching ratio. Film thickness variation increases (deteriorates). In addition, Rt humidity fluctuation, which is retardation (phase difference) in the thickness direction, is caused by water molecules coordinating with the carbonyl groups of cellulose. The larger the amount, the worse the Rt humidity fluctuation tends to be.

The cellulose ester preferably has a total degree of substitution of 2.1 to 2.5. By setting it within this range, environmental fluctuations (particularly Rt fluctuations due to humidity) can be suppressed, and the uniformity of the film thickness can be improved. More preferably, it is 2.2 to 2.45 from the viewpoint of improving the flowability and stretchability during film formation and further improving the uniformity of film thickness.

More specifically, the cellulose ester satisfies both the following formulas (a) and (b). In the formula, X is the degree of substitution of an acetyl group, Y is the degree of substitution of a propionyl group or a butyryl group, or a mixture thereof.

Formula (a): 2.1≦X+Y≦2.5
Formula (b): 0≦Y≦1.5
The cellulose ester is more preferably cellulose acetate (Y=0) or cellulose acetate propionate (CAP) (Y; propionyl group, Y>0), and even more preferably Y=0 to reduce film thickness variation. It is cellulose acetate. Particularly preferably used cellulose acetate is 2.1 ≦ ) cellulose diacetate (DAC). In addition, when Y>0, particularly preferably used cellulose acetate propionate (CAP) is 0.95≦X≦2.25, 0.1≦Y≦1.2, 2.15≦X+Y≦ It is 2.45.

By using the above cellulose acetate or cellulose acetate propionate, a film roll with excellent retardation, mechanical strength, and environmental fluctuations can be obtained.

In addition, the degree of substitution of acyl groups indicates the average number of acyl groups per glucose unit, and how many hydrogen atoms of the hydroxy groups at the 2nd, 3rd, and 6th positions of 1 glucose unit are substituted with acyl groups. shows. Therefore, the maximum degree of substitution is 3.0, which means that the hydrogen atoms of the hydroxyl groups at the 2nd, 3rd, and 6th positions are all substituted with acyl groups. These acyl groups may be substituted on the 2nd, 3rd, and 6th positions of the glucose unit on an average basis, or may be substituted with a distribution. The degree of substitution is determined by the method specified in ASTM-D817-96.

In order to obtain desired optical properties, cellulose acetate having different degrees of substitution may be mixed and used. The mixing ratio of different cellulose acetates is not particularly limited.

The number average molecular weight (Mn) of the cellulose ester is in the range of 2×10 ⁴ to 3×10 ⁵ , more preferably in the range of 2×10 ⁴ to 1.2×10 ⁵ , and even more in the range of 4×10 ⁴ to 8× A value in the range of 10 ⁴ is preferable because the resulting film roll has high mechanical strength.

The number average molecular weight Mn of the cellulose ester is calculated by measurement using gel permeation chromatography (GPC) under the measurement conditions described above.

The weight average molecular weight (Mw) of the cellulose ester is in the range of 2×10 ⁴ to 1×10 ⁶ , further in the range of 2×10 ⁴ to 1.2×10 ⁵ , and even more in the range of 4×10 ⁴ to 8×10 A range of ⁴ is preferable because the resulting film roll has high mechanical strength.

The raw material cellulose for cellulose ester is not particularly limited, but examples include cotton linters, wood pulp, and kenaf. Moreover, the cellulose esters obtained from these can be mixed and used in any desired ratio.

Cellulose esters such as cellulose acetate and cellulose acetate propionate can be produced by known methods. Generally, raw material cellulose is mixed with specified organic acids (acetic acid, propionic acid, etc.), acid anhydrides (acetic anhydride, propionic anhydride, etc.), and catalysts (sulfuric acid, etc.) to esterify cellulose. The reaction proceeds until the triester is produced. In the triester, the three hydroxy groups of the glucose unit are replaced by acylic acid, an organic acid.

When two types of organic acids are used at the same time, mixed ester type cellulose esters, such as cellulose acetate propionate and cellulose acetate butyrate, can be produced. Next, by hydrolyzing the cellulose triester, a cellulose ester resin having a desired degree of acyl substitution is synthesized. After that, cellulose ester resin is completed through processes such as filtration, precipitation, washing, dehydration, and drying. Specifically, it can be synthesized with reference to the method described in JP-A-10-45804.

[2.1.4] Other Additives The film roll of this embodiment may contain the following in addition to the above-mentioned thermoplastic resin as other additives.

(a) Plasticizer The film roll of this embodiment preferably contains at least one plasticizer for the purpose of imparting processability to, for example, a polarizing plate protective film. It is preferable to use the plasticizer alone or in combination of two or more.

Among the plasticizers, it is preferable to include at least one plasticizer selected from the group consisting of sugar esters, polyesters, and styrene compounds for effective control of moisture permeability and compatibility with base resins such as cellulose esters. It is preferable from the viewpoint of achieving both high solubility.

The molecular weight of the plasticizer is preferably 15,000 or less, more preferably 10,000 or less, from the viewpoint of achieving both improvement in heat and humidity resistance and compatibility with the base resin such as cellulose ester. When the compound having a molecular weight of 10,000 or less is a polymer, the weight average molecular weight (Mw) is preferably 10,000 or less. The weight average molecular weight (Mw) is preferably within the range of 100 to 10,000, more preferably within the range of 400 to 8,000.

In particular, in order to obtain the effects of this embodiment, it is preferable to contain the compound having a molecular weight of 1500 or less in the range of 6 to 40 parts by mass, and preferably 10 to 20 parts by mass, based on 100 parts by mass of the base resin. It is more preferable to contain it within the following range. By containing within the above range, effective control of moisture permeability and compatibility with the base resin can be achieved, which is preferable.

<Sugar ester>
The film roll of this embodiment may contain a sugar ester compound for the purpose of preventing hydrolysis. Specifically, as a sugar ester compound, it is possible to use a sugar ester that has at least 1 to 12 pyranose structures or furanose structures and has esterified all or part of the OH groups of that structure. .

<polyester>
In this embodiment, the film roll preferably contains polyester.

Polyesters are not particularly limited, but include, for example, polymers with hydroxyl groups at the ends (polyester polyols) obtained by a condensation reaction of dicarboxylic acids or their ester-forming derivatives with glycols, or polymers with hydroxyl groups at the ends of the polyester polyols, or A polymer in which hydroxyl groups are capped with monocarboxylic acid (end-capped polyester) can be used. The ester-forming derivative referred to herein refers to dicarboxylic acid esters, dicarboxylic acid chlorides, and dicarboxylic acid anhydrides.

<Styrenic compounds>
In addition to or in place of the sugar ester and polyester described above, a styrene compound can also be used in the film roll of this embodiment for the purpose of improving the water resistance of the film.

The styrene compound may be a homopolymer of styrene monomers, or a copolymer of styrene monomers and other comonomers. The content of the structural unit derived from the styrene monomer in the styrene compound may be preferably 30 to 100 mol%, more preferably 50 to 100 mol%, in order for the molecular structure to have a certain bulkiness or more.

Examples of styrenic monomers include styrene; alkyl-substituted styrenes such as α-methylstyrene, β-methylstyrene, and p-methylstyrene; halogen-substituted styrenes such as 4-chlorostyrene and 4-bromostyrene; p-hydroxy Hydroxystyrenes such as styrene, α-methyl-p-hydroxystyrene, 2-methyl-4-hydroxystyrene, and 3,4-dihydroxystyrene; vinylbenzyl alcohols; p-methoxystyrene, p-tert-butoxystyrene, m -Alkoxy-substituted styrenes such as tert-butoxystyrene; Vinylbenzoic acids such as 3-vinylbenzoic acid and 4-vinylbenzoic acid; 4-vinylbenzyl acetate; 4-acetoxystyrene; 2-butylamidostyrene, 4-methylamide Amidostyrenes such as styrene and p-sulfonamidostyrene; aminostyrenes such as 3-aminostyrene, 4-aminostyrene, 2-isopropenylaniline, and vinylbenzyldimethylamine; 3-nitrostyrene, 4-nitrostyrene, etc. Nitrostyrenes; cyanostyrenes such as 3-cyanostyrene and 4-cyanostyrene; vinylphenylacetonitrile; arylstyrenes such as phenylstyrene, indenes, and the like. The styrenic monomer may be used alone or in combination of two or more types.

(b) Optional Components The film roll of this embodiment may contain other optional components such as antioxidants, colorants, ultraviolet absorbers, matting agents, acrylic particles, hydrogen-bonding solvents, and ionic surfactants. These components can be added in an amount of 0.01 to 20 parts by weight based on 100 parts by weight of the base resin.

<Antioxidant>
In the film roll of this embodiment, commonly known antioxidants can be used as antioxidants. In particular, lactone-based, sulfur-based, phenol-based, double bond-based, hindered amine-based, and phosphorus-based compounds can be preferably used.

These antioxidants and the like are added in an amount of 0.05 to 20% by mass, preferably 0.1 to 1% by mass, based on the resin that is the main raw material of the film. Rather than using only one type of these antioxidants, a synergistic effect can be obtained by using several different types of compounds together. For example, it is preferable to use lactone-based, phosphorus-based, phenol-based, and double bond-based compounds in combination.

<Colorant>
The film roll of this embodiment preferably contains a coloring agent for color adjustment within a range that does not impair the effects of this embodiment. The term "coloring agent" refers to a dye or a pigment, and in this embodiment, it refers to a material having the effect of making the color tone of the liquid crystal screen blue-ish, adjusting the yellow index, or reducing haze.

Various dyes and pigments can be used as colorants, but anthraquinone dyes, azo dyes, phthalocyanine pigments, etc. are effective.

<Ultraviolet absorber>
Since the film roll of this embodiment can be used on the viewing side or backlight side of a polarizing plate, it may contain an ultraviolet absorber for the purpose of imparting an ultraviolet absorbing function.

The ultraviolet absorber is not particularly limited, but includes, for example, benzotriazole-based, 2-hydroxybenzophenone-based, or salicylic acid phenyl ester-based ultraviolet absorbers. For example, 2-(5-methyl-2-hydroxyphenyl)benzotriazole, 2-[2-hydroxy-3,5-bis(α,α-dimethylbenzyl)phenyl]-2H-benzotriazole, 2-(3, Triazoles such as 5-di-t-butyl-2-hydroxyphenyl)benzotriazole, 2-hydroxy-4-methoxybenzophenone, 2-hydroxy-4-octoxybenzophenone, 2,2'-dihydroxy-4-methoxybenzophenone Examples include benzophenones such as.

The above ultraviolet absorbers can be used alone or in combination of two or more.

The amount of ultraviolet absorber used varies depending on the type of ultraviolet absorber, conditions of use, etc., but generally it is 0.05 to 10% by mass, preferably 0.1 to 5% by mass, based on the base resin. It is added in a range of %.

<Matting agent>
The film roll of this embodiment preferably contains fine particles (matting agent) that impart slipperiness to the film roll. In particular, addition is effective from the viewpoint of improving the slipperiness of the surface C according to the present embodiment, improving the slipperiness during winding, and preventing the occurrence of scratches and blocking.

The matting agent may be either an inorganic compound or an organic compound as long as it does not impair the transparency of the resulting film roll and has heat resistance during melting. These matting agents can be used alone or in combination of two or more.

By using particles with different particle sizes and shapes (for example, acicular and spherical), it is possible to achieve both high transparency and slipperiness.

Among these, silicon dioxide is particularly preferably used because it has a refractive index close to that of the cycloolefin resin, acrylic resin, and cellulose ester resin, and thus has excellent transparency (haze).

Specific examples of silicon dioxide include Aerosil (registered trademark) 200V, Aerosil (registered trademark) R972V, Aerosil (registered trademark) R972, R974, R812, 200, 300, R202, OX50, TT600, NAX50 (Japan Aerosil Co., Ltd. ), Seahoster (registered trademark) KEP-10, Seahoster (registered trademark) KEP-30, Seahoster (registered trademark) KEP-50 (manufactured by Nippon Shokubai Co., Ltd.), Cylohobic (registered trademark) 100 (Fuji Silicia) Commercial products having trade names such as Nip Seal (registered trademark) E220A (manufactured by Nippon Silica Kogyo Co., Ltd.) and AdmaFine (registered trademark) SO (manufactured by Admatex Co., Ltd.) can be preferably used.

The shape of the particles may be amorphous, acicular, flat, spherical, or the like without any particular restriction, but spherical particles are particularly preferred since the obtained film roll can have good transparency.

If the particle size is close to the wavelength of visible light, light will be scattered and transparency will deteriorate, so it is preferably smaller than the wavelength of visible light, and more preferably 1/2 or less of the wavelength of visible light. . If the particle size is too small, the slipperiness may not be improved, so it is particularly preferable that the particle size is in the range of 80 nm to 180 nm. In addition, the particle size means the size of the aggregate when the particle is an aggregate of primary particles. Furthermore, when the particle is not spherical, it means the diameter of a circle corresponding to its projected area.

The matting agent is preferably added in an amount of 0.05 to 10% by mass, preferably 0.1 to 5% by mass, based on the base resin.

[2.2] Film roll manufacturing method The film roll manufacturing method of this embodiment is characterized by having a step of subjecting at least the portion A or the portion B to a surface modification treatment.

Further, the surface modification treatment is preferably performed only on the site B, and is preferably performed on both the site A and the site B.

Further, as described above, the knurling portion is preferably formed by laser knurling (laser method).

As a manufacturing method of the film roll of this embodiment, a manufacturing method such as a normal inflation method, T-die method, calendar method, cutting method, casting method, emulsion method, hot press method, etc. can be used for film formation. However, from the viewpoints of suppressing coloration, suppressing foreign matter defects, suppressing optical defects such as die lines, etc., the solution casting method and melt casting method are preferable as the film forming method, and the solution casting method is particularly preferred. is more preferred in order to obtain a uniform surface.

<Solution casting film forming method>
When forming a film by the solution drooling method, the method for manufacturing the film roll of this embodiment includes a step of preparing a dope by dissolving the thermoplastic resin and the above-mentioned additives in a solvent (dissolving step; dope preparation step), A process of casting onto an endless metal support that moves infinitely (casting process), a process of drying the cast dope as a web (solvent evaporation process), a process of peeling it off from the metal support (peeling process), drying It is preferable to include a process of stretching and maintaining the width (stretching/width maintaining/drying process), and a process of winding the finished film into a roll (winding process). As the thermoplastic resin, it is particularly preferable to use a cycloolefin resin or an acrylic resin.

FIG. 9 is a diagram schematically showing an example of the dope preparation step, the casting step, and the drying step (solvent evaporation step) of the solution casting film forming method.

Large aggregates are removed from the preparation pot A41 using a filter A44, and the liquid is sent to the stock pot A42. Thereafter, various additive liquids are added from the stock pot A42 to the main dope dissolving pot 1.

After that, the main dope is filtered in the main filter A3, and the additive addition liquid is added in-line to it from A16.

In many cases, the main dope may contain about 10 to 50% by mass of returned material.

Returned materials are finely crushed films, such as those produced when film is produced by cutting off both sides of the film, or original film that has been out of specification due to scratches, etc.

Furthermore, as the raw material for the resin used for preparing the dope, it is also possible to preferably use pellets of cellulose ester and other additives as a base resin.

Each step will be explained below.

(Process 1) Dissolution process (dope preparation process)
Hereinafter, as one embodiment of the present embodiment, the melting step will be described using as an example a case where a cycloolefin resin (hereinafter also referred to as COP) is used as the thermoplastic resin, but the present embodiment is not limited thereto.

This step is a step of dissolving the COP and, if necessary, other compounds in a dissolution pot with stirring in a solvent that is mainly a good solvent for COP, or a step of forming a dope by dissolving the COP and, if necessary, other compounds into the COP solution. This is a step of mixing compound solutions to form a dope, which is the main solution.

It is preferable that the concentration of COP in the dope be higher because it can reduce the drying load after being cast onto a metal support, but if the concentration of COP is too high, the load during filtration will increase and the filtration accuracy will deteriorate. The concentration that achieves both of these is preferably 10 to 35% by mass, more preferably 15 to 30% by mass.

The solvent used in dope may be used alone or in combination of two or more types, but it is preferable to use a mixture of a good solvent and a poor solvent for COP in terms of production efficiency, and the one with more good solvent is preferable from the viewpoint of solubility of COP.

The preferred range of the mixing ratio of the good solvent and poor solvent is 70 to 98% by mass of the good solvent and 2 to 30% by mass of the poor solvent. A good solvent and a poor solvent are defined as a good solvent that dissolves the COP used alone, and a poor solvent as a solvent that swells or does not dissolve the COP used alone. Therefore, a good solvent or a poor solvent changes depending on the average degree of substitution of COP.

The good solvent used in this embodiment is not particularly limited, but includes organic halogen compounds such as methylene chloride, dioxolanes, acetone, methyl acetate, methyl acetoacetate, and the like. Particularly preferred are methylene chloride and methyl acetate.

Further, the poor solvent used in this embodiment is not particularly limited, but for example, methanol, ethanol, n-butanol, cyclohexane, cyclohexanone, etc. are preferably used. Further, it is preferable that the dope contains 0.01 to 2% by mass of water.

Furthermore, the solvent used for dissolving COP is used by recovering the solvent removed from the film by drying in the film forming process and reusing it.

The recovered solvent may contain trace amounts of additives added to COP, such as plasticizers, ultraviolet absorbers, polymers, and monomer components, but even if these are contained, it is preferable to reuse them. It can also be purified and reused if necessary.

When preparing the dope described above, a general method can be used to dissolve COP. Specifically, preferred are a method carried out at normal pressure, a method carried out below the boiling point of the main solvent, and a method carried out under pressure above the boiling point of the main solvent.If heating and pressurization are combined, heating can be carried out above the boiling point at normal pressure.

In addition, a method of stirring and dissolving while heating at a temperature above the boiling point of the solvent at normal pressure and within a range where the solvent does not boil under pressure is also preferable in order to prevent the generation of lumpy undissolved substances called gels and mako.

Also preferably used is a method in which COP is mixed with a poor solvent to make it wet or swell, and then a good solvent is further added to dissolve it.

Pressurization may be performed by injecting an inert gas such as nitrogen gas or by increasing the vapor pressure of the solvent by heating. It is preferable to perform heating from the outside. For example, a jacket type is preferable because the temperature can be easily controlled.

A higher heating temperature after adding the solvent is preferable from the viewpoint of solubility of COP, but if the heating temperature is too high, the required pressure will increase and productivity will deteriorate.

The preferred heating temperature is 45 to 120°C, more preferably 60 to 110°C, and even more preferably 70 to 105°C. Further, the pressure is adjusted so that the solvent does not boil at the set temperature.

Alternatively, a cooling dissolution method is also preferably used, whereby COP can be dissolved in a solvent such as methyl acetate.

Next, it is preferable to filter this COP solution (dope during or after dissolution) using a suitable filter medium such as filter paper.

It is preferable for the filter medium to have a small absolute filtration accuracy in order to remove insoluble matters, but if the absolute filtration accuracy is too small, there is a problem in that the filter medium is likely to become clogged. For this reason, a filter medium with an absolute filtration accuracy of 0.008 mm or less is preferable, a filter medium of 0.001 to 0.008 mm is more preferable, and a filter medium of 0.003 to 0.006 mm is even more preferable.

There are no particular restrictions on the material of the filter media, and ordinary filter media can be used, but filter media made of plastic such as polypropylene or Teflon (registered trademark), or metal filter media such as stainless steel are preferred since they do not cause fibers to fall off. preferable.

It is preferable to remove and reduce impurities contained in the raw COP, particularly bright spot foreign substances, by filtration.

A bright spot foreign substance is a phenomenon in which two polarizing plates are arranged in a crossed nicol state, a film, etc. is placed between them, and when light is applied from one polarizing plate side and observed from the other polarizing plate side, the opposite image appears. These are points (foreign objects) that appear to leak light from the side, and the number of bright spots with a diameter of 0.01 mm or more is preferably 200 pieces/cm ² or less. More preferably, the number is 100 pieces/cm ² or less, still more preferably 50 pieces/m ² or less, and even more preferably 0 to 10 pieces/cm ² or less. Further, it is preferable that there are fewer bright spots with a diameter of 0.01 mm or less.

Filtration of the dope can be carried out in the usual way, but the method of filtering while heating at a temperature above the boiling point of the solvent at normal pressure and within the range where the solvent does not boil under pressure is the most effective method for reducing the filtration pressure before and after filtration. This is preferable because the increase in the difference (referred to as differential pressure) is small.

The preferred temperature is 45 to 120°C, more preferably 45 to 70°C, even more preferably 45 to 55°C.

The smaller the filtration pressure, the better. The filtration pressure is preferably 1.6 MPa or less, more preferably 1.2 MPa or less, even more preferably 1.0 MPa or less.

(Step 2) Casting step Next, the dope is cast onto a metal support. That is, in this step, the dope is sent to a pressurizing die A30 through a liquid sending pump (for example, a pressurizing metering gear pump), and an endless metal belt A31, such as a stainless steel band, or a rotating metal drum, etc., is used to transport the dope indefinitely. This is a process in which the dope is cast from a pressurized die slit onto the casting position on the metal support.

A pressure die is preferred because the slit shape of the die mouthpiece can be adjusted and the film thickness can be easily made uniform. Pressure dies include coat hanger dies, T dies, and the like, and any of them are preferably used. Preferably, the surface of the metal support is a mirror surface. In order to increase the film forming speed, two or more pressure dies may be provided on the metal support, and the doping amount may be divided and layered. Alternatively, it is also preferable to obtain a film roll having a laminated structure by a co-casting method in which a plurality of dopes are simultaneously cast.

The width of the cast is preferably 1.3 m or more from the viewpoint of productivity. More preferably, it is 1.3 to 4.0 m. If the length exceeds 4.0 m, there is a risk that stripes may appear in the manufacturing process or that stability in the subsequent conveyance process may be reduced. More preferably, the length is 1.3 to 3.0 m in terms of transportability and productivity.

The metal support used in the casting process preferably has a mirror-finished surface, and a stainless steel belt or a cast drum with a plated surface is preferably used as the metal support.

The surface temperature of the metal support during the casting process is between -50°C and below the boiling point of the solvent. Higher temperatures are preferable because they allow the web to dry faster, but if the temperature is too high, the web may foam or become flat. properties may deteriorate.

The preferred support temperature is 0 to 55°C, more preferably 22 to 50°C. Alternatively, it is also a preferable method to gel the web by cooling and peel it from the drum in a state containing a large amount of residual solvent.

The method of controlling the temperature of the metal support is not particularly limited, but there are methods such as blowing hot or cold air or bringing hot water into contact with the back side of the metal support. It is preferable to use hot water because heat transfer is more efficient and the time required for the temperature of the metal support to become constant is shorter. When hot air is used, air at a temperature higher than the target temperature may be used.

(Step 3) Solvent evaporation step In this step, the web (the dope film formed by casting the dope on the casting support is called a web) is heated on the casting support to evaporate the solvent. This is the process of

To evaporate the solvent, there are methods such as blowing air from the web side, transferring heat with liquid from the back side of the support, and transferring heat from the front and back using radiant heat. It is preferable because of its good drying efficiency. Moreover, a method of combining them is also preferably used. The web on the support after casting is preferably dried on the support in an atmosphere of 35 to 100°C. In order to maintain the atmosphere at 35 to 100° C., it is preferable to apply warm air at this temperature to the upper surface of the web or to heat it by means such as infrared rays.

From the viewpoints of surface quality, moisture permeability, and peelability, it is preferable to peel the web from the support within 30 to 120 seconds.

(Step 4) Peeling step Next, the web is peeled from the metal support. That is, this step is a step in which the web on which the solvent has been evaporated on the metal support is peeled off at the peeling position. The peeled web is sent to the next process.

The temperature at the peeling position on the metal support is preferably within the range of -50 to 40°C, more preferably within the range of 10 to 40°C, and most preferably within the range of 15 to 30°C.

Note that the amount of solvent remaining on the metal support at the time of peeling is appropriately adjusted depending on the strength of the drying conditions, the length of the metal support, etc. In order for the film to exhibit good flatness, the amount of residual solvent when peeling the web from the metal support is preferably 10 to 150% by mass. When peeling occurs when the amount of residual solvent is larger, if the web is too soft, the flatness will be lost during peeling, and warping or vertical streaks will easily occur due to peeling tension. The amount can be determined. More preferably 20 to 40% by weight or 60 to 130% by weight, particularly preferably 20 to 30% by weight or 70 to 120% by weight.

In this embodiment, the amount of residual solvent is defined by the following formula.

Amount of residual solvent (mass%) = {(MN)/N} x 100
In addition, M is the mass of a sample taken at any time during or after manufacturing the web or film, and N is the mass after heating M at 115° C. for 1 hour.

The peeling tension when peeling the metal support and the film is preferably 300 N/m or less. More preferably, the tension is within the range of 196 to 245 N/m, but if wrinkles are likely to occur during peeling, it is preferable to peel with a tension of 190 N/m or less. The peeling tension is preferably 300 N/m or less.

(Process 5) Drying/stretching/width maintenance process (drying)
In the film drying step, the web is peeled off from the metal support and further dried to reduce the amount of residual solvent to 1% by mass or less, more preferably 0.1% by mass or less, particularly preferably 0. ~0.01% by mass or less.

The film drying process generally uses a roll drying method (a method in which the web is dried by passing it alternately through a number of rollers arranged above and below) or a tenter method, in which the web is dried while being transported. For example, after peeling, the web is transported using a drying device A35 that conveys the web by passing it alternately through a plurality of rollers arranged in the drying device, and/or a tenter stretching device A34 that clips both ends of the web with clips and conveys the web. dry.

The means for drying the web is not particularly limited, and generally hot air, infrared rays, heated rollers, microwaves, etc. can be used, but hot air is preferred from the viewpoint of simplicity. Too rapid drying tends to impair the flatness of the finished film. Drying at high temperatures is preferably carried out when the residual solvent is about 8% by mass or less. Drying is generally carried out within the range of 30 to 250°C throughout. In particular, it is preferable to dry within the range of 35 to 200°C. It is preferable to increase the drying temperature in stages.

When using a tenter stretching device, it is preferable to use a device that can independently control the gripping length (distance from the start of gripping to the end of gripping) of the film on the left and right sides using the left and right gripping means of the tenter. Furthermore, in the tenter process, it is also preferable to intentionally create sections having different temperatures in order to improve flatness.

It is also preferable to provide a neutral zone between different temperature zones so that each zone does not interfere with each other.

(Stretching/width maintenance)
Subsequently, the web peeled from the metal support is preferably stretched in at least one direction. The orientation of molecules within the film can be controlled by stretching. In order to obtain the target retardation values Ro and Rt in this embodiment, it is preferable that the film has the configuration of this embodiment and further controls the refractive index by controlling the transport tension and stretching operation. For example, it is possible to vary the retardation value by lowering or increasing the tension in the longitudinal direction.

As a specific stretching method, biaxial stretching is performed sequentially or simultaneously in the longitudinal direction of the web (film forming direction; casting direction; MD direction) and the direction perpendicular to the web plane, that is, the width direction (TD direction). It can be stretched or uniaxially stretched. Preferably, it is a biaxially stretched film that is biaxially stretched in the casting direction (MD direction) and the width direction (TD direction), but the film according to this embodiment may be a uniaxially stretched film. , or may be an unstretched film. Note that the stretching operation may be performed in multiple steps. Moreover, when biaxial stretching is performed, simultaneous biaxial stretching may be performed or it may be performed in stages. In this case, stepwise means, for example, that stretching in different stretching directions can be carried out sequentially, or that stretching in the same direction can be divided into multiple stages and stretching in different directions can be added to any of the stages. is also possible.

For example, the following stretching steps are also possible:
・Stretching in the casting direction → Stretching in the width direction → Stretching in the casting direction → Stretching in the casting direction ・Stretching in the width direction → Stretching in the width direction → Stretching in the casting direction → Stretching in the casting direction Simultaneous biaxial stretching also includes stretching in one direction and shrinking the other by relaxing the tension.

The final stretching ratio in two axes perpendicular to each other is preferably in the range of 0.8 to 1.5 times in the casting direction and 1.1 to 2.5 times in the width direction. It is preferable to carry it out in the range of 0.8 to 1.2 times in the extending direction and 1.2 to 2.0 times in the width direction.

The stretching temperature is usually preferably carried out within the temperature range of Tg to Tg + 60°C of the resin constituting the film. Usually, the stretching temperature is preferably 120°C to 200°C, more preferably 120°C to 180°C.

The residual solvent in the web during stretching is preferably 20 to 0%, more preferably 15 to 0%. For example, it is preferable to stretch at 135°C with a residual solvent content of 8%, or preferably to stretch at 155°C with a residual solvent content of 11%. Alternatively, it is preferable to stretch at 155° C. with a residual solvent of 2%, or preferably to stretch at 160° C. with a residual solvent of less than 1%.

There is no particular limitation on the method of stretching the web. For example, there is a method in which multiple rollers have different circumferential speeds and the difference in roller circumferential speed is used to stretch the web in the longitudinal direction, or both ends of the web are fixed with clips or pins, and the distance between the clips or pins is increased in the direction of travel. Examples include a method in which the material is stretched in the longitudinal and longitudinal directions, a method in which the material is similarly spread in the transverse direction and then stretched in the transverse direction, and a method in which the material is simultaneously spread in the longitudinal and lateral directions and stretched in both the longitudinal and lateral directions. Of course, these methods may be used in combination. Among these, it is particularly preferable to stretch the web in the width direction (lateral direction) using a tenter method in which both ends of the web are held with clips or the like.

In addition, in the case of the so-called tenter method, it is preferable to drive the clip portion using a linear drive method because smooth stretching can be performed and the risk of breakage etc. can be reduced.

It is preferable to maintain the width or stretch in the lateral direction in the film forming process using a tenter, and a pin tenter or a clip tenter may be used.

The slow axis or fast axis of the film according to the present embodiment exists within the film plane, and if the angle formed with the film forming direction is θ1, it is preferable that θ1 is −1° or more and +1° or less, and −0 More preferably, the angle is .5° or more and +0.5° or less.

This θ1 can be defined as an orientation angle, and θ1 can be measured using an automatic birefringence meter KOBRA-21ADH (manufactured by Oji Scientific Instruments Co., Ltd.). The fact that θ1 satisfies each of the above relationships can contribute to obtaining high brightness in a displayed image, suppress or prevent light leakage, and can contribute to obtaining faithful color reproduction in a color liquid crystal display device.

(Step 6) Winding step Finally, a film roll is obtained by winding up the obtained web (finished film). More specifically, it is a process in which the web is wound up as a film using a winder A37 after the amount of residual solvent in the web is 2% by mass or less, and dimensional stability is achieved by reducing the amount of residual solvent to 0.4% by mass or less. A film with good properties can be obtained. In particular, it is preferable to wind it in a range of 0.00 to 0.10% by mass.

Any commonly used winding method may be used, such as a constant torque method, a constant tension method, a taper tension method, a programmed tension control method with constant internal stress, etc., and any of these methods may be used.

Before winding, the ends are slit to the width of the product and bleeded, and the knurling and surface modification treatments according to this embodiment are applied to both ends of the film to prevent sticking and scratches during winding.

Note that the gripping portions of the clips at both ends of the film are usually cut off because the film is deformed and cannot be used as a product. If the material has not deteriorated due to heat, it will be recycled after recovery.

The film roll of this embodiment is preferably a long film, specifically about 100 m to 10,000 m, and is usually provided in the form of a roll.

<Details of film winding method>
The film after knurling and surface modification treatment is preferably wound up by the following winding method.

The winding method includes a straight winding process in which the film is wound around a core so that the side edges of the film are aligned, and after the straight winding process, the side edges are periodically wound in a certain range in the width direction of the film. It is preferable to have an oscillating winding step of winding the film around the core by periodically vibrating the film or the core in the width direction of the film so that the film is deviated from the core.

In particular, when the winding length of the film reaches a switching winding length that is predetermined within a range of 10 to 30% of the total winding length of the film, switching from the straight winding process to the oscillating winding process. is preferred.

The film winding device includes a film winding unit that rotates a core to wind the film onto the core, and an oscillator that periodically shifts the film in the width direction of the film on the core within a certain range. an oscillating unit that vibrates the film or the winding core in the width direction of the film in conjunction with the winding of the film so that the winding length of the film reaches a predetermined winding length at the time of switching; In some cases, it is preferable to include a switching section that switches the winding of the film from the straight winding to the oscillating winding.

Oscillate winding will be explained below.

As shown in FIG. 10, the film manufacturing line B10 includes a film manufacturing device B11 and a winding device B12. The film manufacturing apparatus B11 manufactures the film 81 using a solution casting method. In the solution casting method, first, a dope is prepared using raw materials. Then, the prepared dope is cast onto an endless support to form a cast film. When the cast membrane becomes self-supporting, the cast membrane is peeled off from the endless support. A film 81 is formed by drying the peeled cast film with hot air or the like. The formed film 81 is sent to the winding device B12 via the knurling roller B15. The knurling roller B15 forms minute irregularities on both side edges (edges) of the film 81 in the width direction by embossing or the like. Note that the height of the unevenness formed by the knurling roller is preferably in the range of 0.5 to 20 μm.

As shown in FIGS. 10 and 11, the winding device B12 includes a winding shaft B19, a winding core holder B20, a core 82 (also referred to as a winding core), a turret B22, guide rollers B23, B24, a dancer roller B25, and an encoder B27. , an oscillating section B29, a winding motor B30, a controller B31, and a dancer section B32. Although the size of the film to be wound in the winding device B12 is not particularly limited, it is preferable that the film has a total winding length of 2,000 to 10,000 m and a width of 500 to 2,500 mm.

As shown in FIG. 10, the winding shaft B19 is attached to the turret B22 with a cantilever support mechanism. The cantilever support mechanism is a mechanism that supports only one end of the winding shaft B19. A core 82 is attached to the winding shaft B19. The core 82 is held at both ends by the core holder B20 of the winding shaft B19. The winding core holder B20 is attached to the winding shaft B19 so as to be slidable in the axial direction (Y direction) of the winding shaft B19 and not to rotate. A winding motor B30 is connected to one end of the winding shaft B19, and is configured to rotate the winding shaft B19. Due to this rotation, the core 82 also rotates, and the film 81 can be wound around the core 82. The leading end of the film 81 is bonded to the core 82 using double-sided tape, adhesive, or the like, and the film 81 is wound around the rotating core 82 starting from this bonded portion. By winding up the film 81, a film roll 80 in which the film 81 is wound into a roll shape is obtained.

A shift mechanism B28 is attached to the turret B22 at the attachment end of the winding shaft B19. This shift mechanism B28 causes the core holder B20 to reciprocate in the axial direction on the winding shaft B19. The shift mechanism B28, the winding shaft B19, and the winding core holder B20 constitute an oscillating section B29. By activating this oscillator B29 and causing the shift mechanism B28 to reciprocate the core holder B20 in the Y direction on the winding shaft B19, the position of the side edge 91a changes within the range of the amplitude Wo every time the film 81 is stacked. This enables oscillating winding in which the film 81 is wound while shifting within the winding. When the oscillating part B29 is not operated, straight winding is possible in which both side edges of the film 81 are aligned. This switching between straight winding and oscillating winding is performed by controller B31.

Here, in the oscillating winding, the oscillating width Wo, which is the amplitude of the oscillating winding, can be set arbitrarily, and the amplitude Wo is preferably within the range of 10 to 30 mm, and within the above range, the amplitude Wo is constant. In addition to being fixed at a value, it may be gradually increased, decreased, or decreased after increasing.

Guide rollers B23, B24 and dancer roller B25 guide the film 81 from the film manufacturing apparatus B11 in the transport direction (X direction). Further, the dancer roller B25 adjusts the winding tension of the film 81 by moving the film 81 in the vertical direction (Z direction) using a shift mechanism B26. This shift mechanism B26 and dancer roller B25 constitute a dancer section B32. Encoder B27 transmits an encoder pulse signal to controller B31 every time guide roller B24 rotates at a constant rotation angle. Note that the guide roller B24 may be provided with a tension sensor that measures the winding tension of the film 81.

The controller B31 controls the driving of the oscillating section B29, the winding motor B30, and the dancer section B32. The controller B31 includes a winding information input section B39, an LUT memory B40, a switching winding length specifying section B41, a winding length measuring section B42, and a switching determining section B43. Winding information such as the total winding length, thickness, and width of the film 81, the outer diameter of the core 82, and the winding tension is input to the winding information input section B39.

The LUT memory B40 stores the winding length of the film 81 when switching from straight winding to oscillating winding (winding length at the time of switching) for each winding information. The switching winding length is preferably set in advance in a range of 10 to 30% of the total length of the film 81, and more preferably in a range of 15 to 25% of the total length of the film 81. There is.

The timing to switch from straight winding to oscillated winding is more preferably when the winding length is in the range of 15 to 25% of the total winding length.

In addition, when switching from straight winding to oscillating winding when the winding length is 10% or more of the total winding length, the surface pressure at the beginning of winding of the film 81 decreases rapidly compared to when switching when the winding length is less than 10%. more reliably prevent this from happening. Therefore, it is possible to more reliably prevent the film roll 80 from becoming loose or misaligned. In addition, when switching after the winding length exceeds 30% of the total winding length, the stress in the circumferential direction of the film 81 will continue to be wound straight even after it leaves the negative region, so that the winding length will be less than 30%. Elongation is more likely to occur in the film roll 80 than in the case of switching at the same time. Therefore, by switching from straight winding to oscillating winding when the winding length is less than 30% of the total winding length, it is possible to more reliably prevent the occurrence of edge elongation than when switching after the winding length exceeds 30%. .

The switching winding length specifying unit B41 compares the winding information stored in the LUT memory B40 with the winding information input to the winding information input unit B39, and determines the switching time corresponding to the input winding information. Determine the winding length. The winding length measuring section B42 measures the winding length of the film 81 wound around the core 82 based on the encoder pulse signal from the encoder B27.

The switching determining unit B43 determines whether the winding length measured by the winding length measuring unit B42 exceeds the winding length at the time of switching specified by the winding length at switching unit B41. If it is determined that the winding length exceeds the switching winding length, an oscillating winding start signal is transmitted to the oscillating section B29. When the oscillating unit B29 receives the oscillating winding start signal, the oscillating unit B29 changes from straight winding, in which the film 81 is wound so that the side edges 91a of the film are aligned, to winding the film 81 while shifting the position of the side edges 91a within the range of the amplitude Wo. The winding of the film 81 is changed to oscillate winding.

<Melt casting film forming method>
The film roll of this embodiment can also be formed by a melt casting method.

"Melt film forming method" is a method in which a composition containing a thermoplastic resin and the above-mentioned additives is heated and melted to a temperature that exhibits fluidity, and then the melt containing the fluid thermoplastic resin is cast. means. As the thermoplastic resin, it is particularly preferable to use cellulose ester.

Molding methods that involve heating and melting can be classified, in detail, into melt extrusion, press molding, inflation, injection molding, blow molding, stretch molding, and the like. Among these molding methods, melt extrusion is preferred from the viewpoint of mechanical strength and surface precision. It is usually preferable that the plurality of raw materials used in the melt extrusion method be kneaded and pelletized in advance.

Pelletization may be carried out by a known method. For example, dry cellulose ester, plasticizer, and other additives are fed to an extruder using a feeder, kneaded using a single-screw or twin-screw extruder, and then passed through a die into strands. This can be done by extruding, water or air cooling, and cutting.

The additives may be mixed before being fed to the extruder, or may be fed from separate feeders.

It is preferable to mix small amounts of additives such as particles and antioxidants in advance in order to mix them uniformly.

It is preferable that the extruder suppresses shearing force, can pelletize the resin so that it does not deteriorate (molecular weight decrease, coloring, gel formation, etc.), and processes at as low a temperature as possible. For example, in the case of a twin-screw extruder, it is preferable to use deep groove type screws and rotate them in the same direction. In terms of uniformity of kneading, the interlocking type is preferred.

A film is formed using the pellets obtained as described above. Of course, it is also possible to directly feed the raw material powder to an extruder using a feeder and form a film without pelletizing it.

The melting temperature when extruding the above pellets using a single-screw or twin-screw extruder is in the temperature range of 200 to 300°C, and after filtering with a leaf disc type filter to remove foreign substances, T The film is cast from a die, the film is nipped between a cooling roller and an elastic touch roller, and the film is solidified on the cooling roller.

When introducing the material from the supply hopper into the extruder, it is also preferable to prevent oxidative decomposition by placing it under vacuum, reduced pressure, or an inert gas atmosphere.

It is preferable to stabilize the extrusion flow rate by, for example, introducing a gear pump. Furthermore, as the filter used to remove foreign matter, a stainless steel fiber sintered filter is preferably used. Stainless fiber sintered filters are made by creating a complex intertwined state of stainless steel fibers, compressing them, and sintering the contact points to integrate them.The density is changed depending on the thickness of the fibers and the amount of compression, and the filtration accuracy is improved. can be adjusted.

Additives such as plasticizers and particles may be mixed with the resin in advance, or may be kneaded in during the extruder. For uniform addition, it is preferable to use a mixing device such as a static mixer.

When nipping a film using a cooling roller and an elastic touch roller, the film temperature on the touch roller side is preferably in the temperature range of Tg of the film to (Tg+110)°C. A known roller having an elastic surface can be used for this purpose.

The elastic touch roller is also called a pinching rotating body. As the elastic touch roller, a commercially available one can also be used.

When peeling the film from the cooling roller, it is preferable to control the tension to prevent deformation of the film.

Furthermore, it is preferable that the film obtained as described above be stretched by the above-mentioned stretching operation after passing through a step of coming into contact with a cooling roller.

For the stretching method, a known roller stretching machine, tenter, etc. can be preferably used. The specific conditions are the same as those for the solution drooling method.

Finally, as in the case of the solution drooling method, the film obtained as described above is wound up to obtain the film roll of this embodiment.

[3] Applications of the film The film unrolled from the film roll of this embodiment is suitably used as an optical film, such as a protective film for a polarizing plate, and is used in various optical measurement devices, liquid crystal display devices, organic electroluminescence display devices, etc. It can be used for display devices.

The present invention will be specifically described below with reference to Examples, but the present invention is not limited thereto. In the examples, "parts" or "%" are used, but unless otherwise specified, "parts by mass" or "% by mass" are expressed.

<Production of film roll>
In addition, although "parts" or "%" are used in the following examples, unless otherwise specified, "parts by mass" or "mass %" is expressed.
<Synthesis of cyclic polyolefin polymer P-1>
100 parts by mass of purified toluene and 100 parts by mass of norbornenecarboxylic acid methyl ester were charged into a reaction vessel. Next, 25 mmol% of ethylhexanoate-Ni (based on monomer mass) dissolved in toluene, 0.225 mol% of tri(pentafluorophenyl)boron (based on monomer mass), and 0.25 mol% of triethylaluminum dissolved in toluene (based on monomer mass) ) was added to the reaction vessel. The reaction was allowed to proceed for 18 hours at room temperature with stirring. After the reaction was completed, the reaction mixture was poured into excess ethanol to form a polymer precipitate. The polymer (P-1) obtained by purifying the precipitate was vacuum dried at 65° C. for 24 hours.

<Preparation of dope D-1>
The following composition was put into a mixing tank, stirred to dissolve each component, and then filtered through a filter paper with an average pore size of 34 μm and a sintered metal filter with an average pore size of 10 μm to prepare a dope.

Cyclic polyolefin polymer P-1 150 parts by mass Dichloromethane 380 parts by mass Ethanol 70 parts by mass Next, the following composition prepared by the above method was charged into a dispersion machine to prepare a fine particle dispersion (M-1).

Fine particles (Aerosil R812: manufactured by Nippon Aerosil Co., Ltd., primary average particle diameter: 7 nm, apparent specific gravity 50 g/L) 4 parts by mass Dichloromethane 76 parts by mass Ethanol 20 parts by mass Cyclic polyolefin solution (dope D-1) 10 parts by mass The above cyclic polyolefin solution and 0.75 parts by mass of the fine particle dispersion were mixed to prepare a film-forming dope. The dope was cast in a width of 1800 mm on a film forming line, dried on a metal support until it had self-supporting properties, and then stripped off as a web and introduced into a tenter.

The residual solvent in the web at the time of introduction into the tenter was 5 to 15% by mass. The film was transported in a tenter at a stretching ratio of 20% in the width direction and at a temperature inside the tenter of 160°C. Thereafter, it was dried and slit to adjust the film roll width to 2200 mm and film thickness to 40 μm.

<Knurling process>
Laser light was irradiated to form a knurling part (part A).

The knurling width at both ends was 15 mm from the edge of the film. The line speed for conveying the film was 10 m/min.

As the laser device, a carbon dioxide laser device was used, the output of the laser device was 20 W, the center wavelength of the light emission wavelength was 9.4 μm, and the light emission wavelength range was set to ±0.01 μm or less around the center wavelength.

To irradiate the film with laser light, a collimated beam emitted from a carbon dioxide laser device is reflected by two galvanometer mirrors, and focused on the surface of the film being transported via an fθ lens (focal length 200 mm). This was done by lighting it. By controlling the angle of the galvano mirror, the light condensing position was moved in the plane of the film, thereby controlling the locus of laser light irradiation onto the film surface.

<Surface modification treatment: atmospheric pressure plasma treatment process>
AGP-500 manufactured by Kasuga Denki was installed on the back side (part B) of the knurling part (part A) of the film, and irradiated with 0.5 kW. The distance between the probe that emits atmospheric pressure plasma and the film was 5 mm. The installation position was set so that the atmospheric pressure plasma to be irradiated could be irradiated to a width of 110% of the width of the knurling part on the back side of the film facing the knurling part.

<Winding process>
A double-sided tape 89 (not shown in FIG. 11) was attached to the core 82 along the axial direction (Y direction), thereby joining the tip of the knurling film 81 to the core 82. The film subjected to the knurling process was wound up. The initial tension was 150N, the taper was 70%, and the corner was 25%. The film roll 80 immediately after being produced in the winding process is moved manually or automatically by a moving mechanism (not shown) in a subsequent process and is attached to the above-mentioned film roll holding device 1 to the holding position (Fig. 1, see FIG. 7 (step S01), etc.).

Using TR, the average air layer thickness contained in the initial film roll was suppressed to 1.0 μm.

The winding length was 3900m or 7800m.

Through the above steps, film rolls commonly used in each of the Examples (Examples 1 to 8 below and Comparative Examples) were produced.

<Failure evaluation test>
Tables 1 to 3 shown in FIGS. 12A to 12C show the experimental conditions and evaluation results of Examples 1 to 8 and Comparative Example.

(Common conditions)
The film rolls for each Example and Comparative Example used were those produced in the above Examples with an average film thickness of 40 μm and a roll width of 2200 mm. A film roll immediately after production (immediately after the winding process) was used as the evaluation start point, and was held in the holding section 30 of the film holding device 1 in a state where the axis (core 82) was horizontal as shown in FIG. In this initial left-standing state, the double-sided tape 89 was oriented upward (0 degree angle position) (see FIGS. 3 and 6). Further, the storage environment and evaluation were performed in an atmosphere of 23° C. and 55% RH.

(Suppression processing and evaluation timing)
Regarding Examples 1 to 8, the failure prevention process due to rotation shown in FIGS. 7 and 8 was performed during the 14-day storage period. On the other hand, in the comparative example, no suppression treatment was performed and the sample was kept as it was during the standing period. The evaluation timing was after the 14-day standing period had elapsed, and the following evaluation items 1 and 2 were evaluated. Note that in Tables 1 to 3, Example 1 and Comparative Example are listed redundantly for ease of viewing.

(Judgment timing and judgment threshold for suppression processing)
In Examples 1 to 8, the determination timing of the suppressing operation (step S04 in FIG. 7), that is, the measurement cycle during leaving is once a day (24 hours). The measurement points are three points on the upper side surface, that is, measurement points p01, p02, and p03. The voids were used as an index value obtained by averaging. The rate of change was used to repair the threshold for determining the change over time (step S07 in FIG. 7). The value is the judgment threshold (change rate 12%, 20%, or 40%) listed in Tables 1 to 3 for the first or second time in the suppression treatment by rotation while left for 14 days. Using. In addition, in Example 8 (Table 3), the second determination threshold is not based on the index value after the immediately preceding first rotation process, but is based on the initial index value for the second time as well, and is set based on this index value. We used the change over time from . The initial index value is an index value obtained by measurement immediately after production.

(“Regular rotation processing” other than judgment based on index values)
For Examples 1 to 7, periodic rotation processing was performed for the second and subsequent times, and for Example 8, for the third and subsequent times, rotation processing was performed periodically. The periodic rotation processing is performed to determine the level of failure caused by the rotation processing (hereinafter also referred to as rotation processing based on index values) based on the judgment of the temporal change in the index value shown in FIG. 7 up to the first (second time in Example 8) This is done to ensure that it is maintained without further deterioration. This periodic rotation process was performed at a rotation speed of 1 degree/min with a rotation amount of 180 degrees every 1 day (24 hours) after the previous rotation (more precisely, after the start of rotation). For example, in Example 1, the first rotation process using the index value is performed on the second day (48 hours) after the start of storage, and thereafter, the rotation process is performed periodically 12 times over 12 days from the 3rd day to the 14th day. A rotation process of 180 degrees was performed. Immediately after the rotation treatment on the 14th day, the evaluation items were evaluated. In Example 3, the first rotation process using the index value is performed on the 6th day, and thereafter, 8 regular rotation processes are performed from the 7th day to the 14th day, and immediately after the last rotation process, We conducted an evaluation regarding the evaluation items.

(Rotation conditions for rotation processing)
The rotation amount and rotation speed of one rotation process are as listed in Tables 1 to 3, and are any of 90, 180, and 360 degrees. The rotation direction is the same "winding direction" for both index value-based rotation processing and periodic rotation processing.

(Evaluation method)
(Evaluation item 1)
Evaluation item 1 is buckling deformation based on appearance evaluation.

Roll buckling deformation refers to a phenomenon in which air caught in a film roll escapes over time, causing the roll to cave in or buckle.

Rank of film buckling deformation (capping) A: No roll deformation at all;
B: There is almost no roll deformation.
C: There are slight buckling points,
D: There is roll deformation, and the entire surface is uneven.

(Evaluation item 2)
Evaluation item 2 is tape transfer based on appearance evaluation. After leaving the film roll for 14 days, the film roll is rewound and tape transfer (also called core transfer), where point-like deformation of 50 μm or more or band-like deformation in the width direction is clearly visible, occurs up to several meters from the core. We measured how well they were doing and ranked them into the following levels.

A: No tape transfer occurred;
B: Weak level up to 50m from the winding core,
C: Weak level up to 100m from the winding core,
D: Strong level up to 100m from the winding core (level that can be easily confirmed visually).

(Evaluation results)
Table 1 shows the difference depending on the change rate determination threshold (step S07 in FIG. 7). The evaluation results were worse in the order of Examples 1, 2, and 3. In Example 3, although it is improved over the comparative example, a failure of evaluation level C occurs. It can be seen that in order to achieve an evaluation level of B or higher, the appropriate determination threshold is 20% or less, more preferably 12% or less.

Table 2 shows the results in which the rotation amount and rotation speed are varied in one rotation process in the rotation process based on the index value when the same determination threshold is used. As for the amount of rotation, from a comparison of Examples 1, 4, and 5, it can be seen that 180 degrees (half rotation) gives the best evaluation results compared to rotations of 90 and 360 degrees.

As for the rotation speed, from a comparison between Example 1 and Example 6, it can be seen that a rotation speed of 1 degree/min shows better evaluation results than a rotation speed of 5 degrees/min. Furthermore, although the winding lengths are different between Example 1 and Example 7, the other conditions regarding the suppression process are the same. Even with the roll length of 7,800 m in Example 7, good evaluation results equivalent to those of 3,900 m in Example 1 were obtained, indicating that the preventive treatment of this embodiment can be used up to 7,800 m.

Table 3 evaluates the degree of influence due to the difference in the amount of rotation in the second rotation process. In the first embodiment, the second rotation process is a periodic rotation process, in which rotation is performed for 180 degrees at a rotation speed of 1 degree/min. In Example 8, the second rotation process is a rotation process based on an index value, and rotation is performed by 90 degrees at a rotation speed of 1 degree/min. Note that the timing of the second rotation process in Example 1 and Example 8 is determined by periodic and index value, and the processing method is different, but it happens to be performed on the same third day. As shown in Table 3, the evaluation results of Example 8 are worse than those of Example 1.

From the above, each condition is the condition of Example 1, the determination threshold is 12% or less, the rotation amount in one suppression process is 180 degrees, and the rotation speed is 1 degree/min. It can be seen that the condition gives the best evaluation results.

The structure of the film roll holding device 1 explained above is the main structure explained in explaining the features of the above embodiment, and is not limited to the above structure, and various modifications can be made within the scope of the claims. Can be done. Moreover, the configuration provided in a general image forming apparatus is not excluded.

For example, as a modification, the film roll holding device 1 may further include an injection part that injects inert gas from the side of the film roll 80 held by the holding part 30. As a result, rotation processing is performed based on the index value, and inert gas is injected. This can suppress the decrease in voids and, in turn, suppress the failure of the film roll.

Further, the means and methods for performing various processes in the film roll holding device 1 according to the embodiment described above can be realized by either a dedicated hardware circuit or a programmed computer. The program may be provided by a computer-readable recording medium such as a USB memory or a DVD (Digital Versatile Disc)-ROM, or may be provided online via a network such as the Internet. In this case, the program recorded on the computer-readable recording medium is usually transferred and stored in a storage unit such as a hard disk. Further, the above program may be provided as a standalone application software, or may be incorporated into the software of the device as a function of the device.

This application is based on a Japanese patent application (Japanese Patent Application No. 2022-80606) filed on May 17, 2022, the disclosure content of which is incorporated by reference in its entirety.

1 Film roll holding device 10 Control section 11 Analysis section 12 Change amount calculation section 13 Suppression control section 20 Storage section 30 Holding section 313 Rotating mechanism 40 Imaging device 41 Imaging unit 45 Moving mechanism 50 Operation panel 80 Film roll 81 Film 82 Core (rolling) core)
89 Double-sided tape A1 Melting pot A2, A5, A11, A14 Liquid pump A3, A6, A12, A15 Filter A4, A13 Stock tank A8, A16 Conduit A10 Additive charging pot A20 Merging pipe A21 Mixer A30 Die A31 Metal Support body A32 Web A33 Peeling position A34 Tenter device A35 Roller dryer A36 Roller A37 Winder A41 Stock tank A43 Pump A44 Filter B10 Film manufacturing line B11 Film manufacturing device B12 Winding device B15 Knurling section B19 Winding shaft B20 Winding core holder B22 Turret B23, B24 Guide roller B25 Dancer roller B26 Shift mechanism B27 Encoder B28 Shift mechanism B29 Oscillator section B30 Winding motor B31 Controller B32 Dancer section B39 Winding information input section B40 LUT memory section B41 Switching winding length specification section B42 Winding length Measuring section B43 Switching judgment section

Claims

a holding unit that holds a film roll formed by winding a film around a core;
a rotation mechanism that rotates the film roll held by the holding section;
a measuring unit that measures a side surface of the film roll held by the holding unit to generate measurement data;
an analysis unit that generates an index value regarding voids between film layers by analyzing the measurement data;
an inhibition control unit that determines whether or not the change in the index value over time exceeds a determination threshold, and when it is determined that the change over time exceeds the determination threshold, causes the rotation mechanism to rotate the film roll by a predetermined amount;
A film roll holding device comprising:
The film roll holding device according to claim 1, wherein the suppression control unit determines the change over time by comparing the index value at a past first timing with the index value at a current timing.
The film roll holding device according to claim 2, wherein the first timing is a timing immediately after production of the film roll.
The first timing is the timing immediately after the production of the film roll, or the timing immediately after the rotation mechanism rotates the previous film roll,
The film roll holding device according to claim 2, wherein the suppression control unit repeatedly rotates the film roll by the rotation mechanism every time it is determined that the determination threshold value is exceeded.
The measuring unit is an imaging device that photographs a side surface of the film roll as a photographing area,
The film roll holding device according to any one of claims 1 to 4, wherein the analysis section generates the index value by analyzing image data generated by the imaging device.
The film roll holding device according to claim 5, wherein the index value is a gap in the radial direction determined from the number of layers of the film included in a predetermined distance in the photographing area and the thickness of the film.
The change over time is a reduction rate of the void,
The film roll holding device according to claim 6, wherein the determination threshold value is any value in the range of 10% to 30%.
The film roll holding device according to any one of claims 1 to 4, wherein the measuring section measures a side surface above the core among the side surfaces of the film roll held by the holding section.
The holding unit holds the film roll in a state where the tape that joins the film to the core is located on the upper side of the core,
The film roll holding device according to claim 8, wherein the measuring section measures a side surface above the core among the side surfaces of the film roll held by the holding section.
The suppression control unit rotates the film roll by a predetermined angle within a range of 1 to 180 degrees in the winding direction or the opposite direction as the predetermined amount of rotation when determining that the determination threshold is exceeded. The film roll holding device according to any one of claims 1 to 4.
a step (a) of generating measurement data by measuring a side surface of the film roll held by a holding unit that holds a film roll formed by winding a film around a core;
(b) generating an index value regarding voids between film layers by analyzing the measurement data;
determining whether or not the change over time of the index value exceeds the determination threshold, and when determining that the change over time exceeds the determination threshold, rotating the film roll held by the holding unit by a predetermined amount by a rotation mechanism ( c) and
A method for suppressing failure of a film roll that performs processing including.
A holding part that holds a film roll formed by winding a film around a core, a rotation mechanism that rotates the film roll held by the holding part, and a side surface of the film roll held by the holding part. A control program for controlling a film roll holding device comprising: a measurement unit that generates measurement data;
(a) measuring a side surface of the film roll held by the holding unit to generate measurement data;
(b) generating an index value regarding voids between film layers by analyzing the measurement data;
determining whether the change over time of the index value exceeds a determination threshold, and when determining that the change over time exceeds the determination threshold, rotating the film roll held by the holding unit by a predetermined amount by the rotation mechanism; (c) and
A control program that causes a computer to perform processes including