Thin film rolls, their manufacturing methods, polarizers, and display devices

Abstract

This invention provides a thin film roll, its manufacturing method, a polarizer, and a display device, which have no winding deviation during transportation and no adhesion failure during long-term storage. The thin film roll does not have an embossing part, characterized in that, when the thickness of the gap layer between adjacent films on the periphery of the core, measured on the side of the width direction of the thin film roll, is set as X [μm], and the thickness of the gap layer between adjacent films on the periphery of the roll is set as Y [μm], X and Y satisfy the following relationship (1) to (3): Equation (1) X < Y; Equation (2) 0.15 < X < 0.40; Equation (3) 1 < (Y / X) ≤ 3.

Description

Technical Field

[0001] This invention relates to thin film rolls, methods for manufacturing the same, polarizers, and display devices. More specifically, it relates to thin film rolls that exhibit no winding deviation during transport and do not experience adhesion failures during long-term storage. Background Technology

[0002] In recent years, with fierce price competition in the LCD TV market, polarizer manufacturers have been researching cost reduction measures such as reducing replacement losses. In response to these measures, the thin films used in polarizers are being developed into longer strips.

[0003] By making the film elongated, costs can be expected to be reduced in various aspects such as splicing losses, inspection time, transportation, and auxiliary materials. For the convenience of storage / transportation, the film is usually wound into rolls after manufacturing.

[0004] However, especially when the film is rolled into a long strip, winding deviations may occur during product transportation. When the film roll is stored for a long time, there is a problem of adhesion due to air leakage between the films.

[0005] As a solution to the above problems, one approach is to wrap the protective film together with the product, but this would result in the protective film becoming unusable.

[0006] As a method to solve the above problems without generating waste, one approach is to pre-emboss the ends of the film and draw air into the spaces between the films during winding to form a void layer (also called an "air layer") of appropriate thickness, thereby suppressing adhesion between the films.

[0007] However, compared with the method of winding together with the protective film, the above-mentioned embossing method has a smaller effect on preventing adhesion, especially on the outer part of the roll, where air between the films will escape over time, thus making adhesion problems more likely to occur.

[0008] In addition, when the void layer is made thicker in order to suppress the above-mentioned adhesion failure, there is a problem of winding deviation during product transportation.

[0009] Patent document 1 discloses a method in which, during film winding, the amount of air drawn into the film is kept constant by varying the winding tension and the embossing height at the film end to correspond to the roll diameter of the film roll. However, there is still room for improvement in order to solve the above problems.

[0010] It should be noted that the "void layer" mentioned in this specification refers to a layer formed by the gap between the opposing surfaces of adjacent films in a film roll, which may contain air or other substances besides air (such as inert gases). Strictly speaking, although the layer composed of air in this "void layer" is called an "air layer", since the two are not distinguished, and especially without affecting the present invention, this "air layer" is referred to as a "void layer".

[0011] In addition, the form in which tiny bumps and protrusions on the surface of one adjacent film come into contact with the surface of the opposite film at some point is also a form of void layer.

[0012] Existing technical documents

[0013] Patent documents

[0014] Patent Document 1: Japanese Patent Application Publication No. 2013-46966 Summary of the Invention

[0015] The technical problem that the invention aims to solve

[0016] The present invention was made in view of the above-mentioned problems / conditions, and aims to provide a thin film roll that has no winding deviation during transport and does not suffer from adhesion failure during long-term storage, a method for manufacturing the same, a polarizer, and a display device.

[0017] Technical solutions for solving technical problems

[0018] In order to solve the above-mentioned problems, the inventors of the present invention conducted research on the causes of the problems and found that the above-mentioned problems could be solved by making the thickness of the gap layer between the films on the outer periphery of the roll thicker than the thickness of the gap layer on the periphery of the core, instead of embossing the film roll. This led to the development of the present invention.

[0019] That is, the above-mentioned problems of the present invention can be solved by the following method.

[0020] 1. A film roll without an embossing section, characterized in that, when the thickness of the gap layer between adjacent films at the periphery of the core, measured on the side surface of the film roll in the width direction, is set as X [μm], and the thickness of the gap layer between adjacent films at the periphery of the roll is set as Y [μm], X and Y satisfy the following relationship (1) to (3).

[0021] Formula (1)X<Y

[0022] 2. The thin film roll as described in the first item, characterized in that the X [μm] and the Y [μm] satisfy the following formula (2) and the following formula (3).

[0023] Equation (2) 0.15 < X < 0.40

[0024] Formula (3) 1<(Y / X)≤3

[0025] 3. A method for manufacturing a film roll, wherein the film roll is not having an embossing part, the method is characterized in that, when the thickness of the gap layer between the films adjacent to each other in the width direction side portion of the film roll is set as X [μm] and the thickness of the gap layer between the films adjacent to each other in the outer periphery portion of the roll is set as Y [μm], X and Y are adjusted to satisfy the relationship of the following formula (1).

[0026] Formula (1)X<Y

[0027] IV. The method for manufacturing a thin film roll as described in the third item, characterized in that the X [μm] and the Y [μm] are adjusted to satisfy the following formulas (2) and (3).

[0028] Equation (2) 0.15 < X < 0.40

[0029] Formula (3) 1<(Y / X)≤3

[0030] V. A method for manufacturing a film roll as described in item 3 or 4, characterized in that the film contact pressure at the periphery of the roll core is adjusted to a range of 6 to 55 [N / m], the film contact pressure at the center of the roll is adjusted to a range of 4 to 40 [N / m], and the film contact pressure at the outer periphery of the roll is adjusted to a range of 3 to 30 [N / m].

[0031] 6. A polarizer, characterized in that it is provided with a portion of the thin film of the thin film roll described in the first or second item.

[0032] 7. A display device, characterized in that it is provided with a portion of the thin film of the thin film roll described in the first or second item.

[0033] The effects of the invention

[0034] Using the method described above, it is possible to provide a thin film roll that has no winding deviation during transport and does not experience adhesion failure during long-term storage, a method for manufacturing the same, a polarizer, and a display device.

[0035] The mechanism of action or manifestation of the effects of this invention is not yet clear, but the following speculations are made.

[0036] The film roll of the present invention does not undergo embossing. Instead, the thickness of the gap layer between the films on the outer periphery of the roll is greater than the thickness of the gap layer on the periphery of the core. As a result, winding deviation will not occur during transport, and adhesion failure can be prevented during long-term storage.

[0037] Existing embossed film rolls only support the film in the embossed portion, so the restraining force used to prevent winding deviation is applied to the embossed portion, causing stress shift in the film. As a result, a particularly large amount of air escapes between the films on the outside of the roll, resulting in uneven thickness of the void layer and adhesion failure during long-term storage.

[0038] In contrast, the film roll of the present invention does not have an embossed part. The film is supported as a whole by the tiny contact surfaces between the films. Compared with the core side, the void layer on the outer side of the roll is thickened. Therefore, even if the amount of air leakage between the films on the outer side of the roll increases during long-term storage, it is difficult for the thickness of the void layer to be uneven. The stress applied to the film is uniform, so it is speculated that adhesion problems can be eliminated.

[0039] The above-mentioned "tiny contact surfaces between thin films" will be explained.

[0040] Although the film roll of the present invention is not embossed, it typically has tiny irregularities at the nanoscale on the surface of the film. Thus, a large number of protrusions on the opposing surfaces of adjacent films come into contact with each other at some point, and the film is supported by the tiny contact surface of the protrusions as a whole.

[0041] That is, for example, a portion of the protrusions are in contact, so the films are not only supported by a void layer, such as an air layer, but also by multiple contact points generated by the tiny bumps.

[0042] Here, we consider the inertial force acting on the width direction (long axis direction of the core) of the film roll during film roll transport.

[0043] Figure 1 This is a conceptual diagram of an inertial force applied to the film near the core side, in the direction of the film roll width. Figure 2 It is a conceptual diagram of an inertial force applied to a thin film near the outer edge of the roll, in the direction of the roll width.

[0044] observe Figure 1 and Figure 2 It can be seen that when the core is R and the film wound into a film roll (30) near the core (R) is F... in Make the film near the outer edge of the roll F out At the same time, although for the film (F) near the core (R) side in Applying an amount equivalent to winding the film (F) in The inertial force of the mass of the thin film layer (L1) closer to the outer edge of the roll, but for the thin film (F) closer to the outer edge of the roll. out Only when the film (F) is wrapped with something equivalent to that of the film, is an application made. out The inertial force of the mass of the thin film layer (L2) closer to the outer side of the roll.

[0045] As described above, for the film (F) near the core (R) side in The effect is greater than that of the film closer to the outer edge of the roll (F). out The inertial force is greater than the mass, and the inertial force is proportional to the mass. Therefore, it can be considered that for this thin film (F) in The effect is better than that of the thin film (F). out The greater inertial force makes it easier for winding deviations to occur on the core side.

[0046] In contrast, the film roll of the present invention has a thicker gap layer between the films at the outer periphery of the roll than the thickness of the gap layer between the films at the core periphery. Therefore, the frictional force acting between the films at the core periphery is relatively increased compared to the outer periphery. Thus, it can be inferred that, in balance with the inertial force acting on the core side as described above, the situation that easily generates winding deviations on the core side as described above can be suppressed. Attached Figure Description

[0047] Figure 1 It is a conceptual diagram of the inertial force applied to the film near the core side, in the direction of the film roll width.

[0048] Figure 2 It is a conceptual diagram of an inertial force applied to a thin film near the outer edge of the roll, in the direction of the roll width.

[0049] Figure 3 It is a general diagram showing the positional relationship between the side of the film roll in the width direction and the imaging device.

[0050] Figure 4 This is an overview view of the side face when viewed from a plane perpendicular to the width direction of the film roll.

[0051] Figure 5 It is a processing image used to calculate the thickness of the void layer.

[0052] Figure 6 This is a simplified conceptual diagram illustrating a portion of the width-direction side surface of a film roll, used to explain the core periphery, the roll center, and the outer periphery.

[0053] Figure 7 This is a schematic diagram of the internal structure of the camera unit.

[0054] Figure 8 This is a schematic diagram of the system structure of the camera device.

[0055] Figure 9 This is a flowchart illustrating the manufacturing process of solution casting film formation.

[0056] Figure 10 This is a schematic diagram of an apparatus for manufacturing thin films using a solution casting method.

[0057] Figure 11 It is a top view schematically showing the internal structure of the tenter frame's stretching device.

[0058] Figure 12 This is a top view showing the state after the cover of the tenter frame's stretching device has been removed.

[0059] Figure 13 This is an overview diagram of the nozzle and heater arrangement in the three zones inside the tenter frame when viewed from the front.

[0060] Figure 14 This is a side view of three zones inside the tenter frame of a tenter frame.

[0061] Figure 15 This is a schematic diagram showing the process of winding the film and a cross-sectional view of the film roll of the present invention after winding.

[0062] Figure 16 This is a flowchart illustrating the manufacturing process of the melt casting film method.

[0063] Figure 17 This is a schematic diagram of an apparatus for manufacturing thin films using the melt casting method.

[0064] Figure 18 This is a schematic diagram illustrating an example of the structure of the liquid crystal display device of the present invention.

[0065] Figure 19 This is a conceptual diagram representing the left-right deviation of the end face in the width direction of the film roll.

[0066] Explanation of reference numerals in the attached figures

[0067] 1, 1a Mixing device (mixing tank); 2 Casting die; 3 Support body (ring belt, roller); 3a, 3b Roller body; 4 Peeling roller body; 5 Cast film; 6 Drying device; 7 Stretching device (tentative stretching device, oblique stretching device); 8 Cutting section; 9 Stretching device (tentative stretching device); 10 Cutting section; 11 Drying device; 12 Cutting section; 13 Winding device; 14 Extruder; 15 Casting die; 16 Casting roller, support body; 16a Contact roller body; 17 Cooling roller; 19 Stretching device (tentative stretching device); 20 Cutting section; 21 Stretching device (tentative stretching device); 22 Cutting section; 23 Winding device; 30 Film roll; 31 Film; 32 Roller body; 33 Contact roller body; 40 Stretching device (tentative stretching device); 42 Cloth clip; 46 Cover body; 48 Circular chain; 50 Drive sprocket; 52 Driven sprocket; 54 Guide rail; 56 Open component; 60 Total reflection mirror; 61 Semi-reflective mirror; 62 Telecentric lens; 63 High-brightness line illumination; 64 Monochromatic line sensor-camera; 80 Temperature distribution sensor; 101 Nozzle fixing part; 102 Nozzle; 103 Cast film; 104 End nozzle; 105 Central nozzle; 106 Cloth clip cover; 200 Liquid crystal display device; 210 First polarizer; 211 Polarizer protective film disposed on the side of the first polarizer opposite to the liquid crystal cell side; 212 First polarizer; 213 Polarizer protective film disposed on the liquid crystal cell side side of the first polarizer; 220 Liquid crystal cell; 230 Second polarizer; 231 Polarizer protective film disposed on the liquid crystal cell side side of the second polarizer; 232 Second polarizer; 233 A polarizer protective film disposed on the side of the second polarizer opposite to the liquid crystal cell side; 240 Backlight; A Peripheral portion of the roll core; B Central portion of the roll; C Outer peripheral portion of the roll; F Thin film; F in The film near the core side; F out The film closer to the outer side of the roll; L1 is a film layer wound closer to the outer side of the roll than the film closer to the core side; L2 is a film layer wound closer to the outer side of the roll than the film closer to the outer side of the roll; H A H B Width; Q: Thermocouple, Infrared (IR) heater; E: Imaging device; R: Core; TD: Width direction of the film roll; U: Imaging unit; P: Any point on the side face of the film roll in the width direction; S: Measured surface of the film roll (side face in the width direction); S0: Core surface; S1: Film layer adhered to the core surface; S2: Film layer forming the boundary between the core periphery and the center of the roll; S3: Film layer forming the boundary between the center of the roll and the outer periphery; S4: Outermost film layer of the film roll; S L The longest end face among the end faces in the width direction of the film roll; SS The shortest end face among the end faces in the width direction of the film roll; P 20 Position where the roll diameter is 20%; P 50 Position where the roll diameter is 50%; P 80 The position where the roll diameter is 80%. Detailed Implementation

[0068] The film roll of the present invention is a film roll without an embossing part. It is characterized in that when the thickness of the gap layer between the films adjacent to each other in the width direction of the film roll is X [μm] and the thickness of the gap layer between the films adjacent to each other in the outer periphery of the roll is Y [μm], X and Y satisfy the relationship of the formula (1).

[0069] Based on the above features, the problems of the present invention can be solved.

[0070] Furthermore, the method for manufacturing a film roll of the present invention is a method for manufacturing a film roll without an embossing processing part, characterized in that, when the thickness of the gap layer between the films adjacent to each other in the width direction side portion of the film roll is set as X [μm] and the thickness of the gap layer between the films adjacent to each other in the outer periphery portion of the roll is set as Y [μm], X and Y are adjusted to satisfy the relationship of the formula (1).

[0071] The two features mentioned above are common or corresponding technical features in the following implementation methods (forms).

[0072] As an embodiment of the present invention, from the perspective of preventing winding deviation during transportation and suppressing adhesion failure during long-term storage, it is preferable that X [μm] and Y [μm] satisfy the above formula (2) and formula (3).

[0073] From the perspective of preventing winding deviation during transportation and suppressing adhesion failure during long-term storage, it is preferable to adjust X [μm] and Y [μm] to satisfy Equation (2) and Equation (3).

[0074] From the perspective of preventing winding deviation during transport and suppressing adhesion failure during long-term storage, it is preferable to adjust the film contact pressure at the periphery of the core to the range of 6 to 55 [N / m], the film contact pressure at the center of the roll to the range of 4 to 40 [N / m], and the film contact pressure at the outer periphery of the roll to the range of 3 to 30 [N / m].

[0075] A portion of the thin film in the thin film roll of the present invention can be suitably used by being disposed on a polarizer.

[0076] A portion of the thin film of the present invention can be suitably used by being disposed in a display device.

[0077] The present invention and its main structural components, as well as the manner / form for implementing the invention, will be described in detail below. It should be noted that in this application, "~" is used to encompass the numerical values ​​preceding and following it as both lower and upper limits.

[0078] 1. Thin film roll

[0079] (1.1) Overview of film rolls

[0080] The film roll of the present invention is a film roll without an embossing processing part, characterized in that, when the thickness of the gap layer between the films adjacent to each other in the width direction side portion of the film roll is set as X [μm] and the thickness of the gap layer between the films adjacent to each other in the outer periphery portion of the roll is set as Y [μm], X and Y satisfy the following relationship (1).

[0081] Formula (1)X<Y

[0082] The film roll of the present invention ("film roll" refers to a film wound into a roll) has a thicker interlayer between the films at the outer periphery of the roll than the thickness of the interlayer at the periphery of the core. Therefore, the frictional force of the film acting on the core side is increased, which can prevent winding deviation, especially at the periphery of the core, during transport.

[0083] Furthermore, since there is no embossed part, but the film is supported by the tiny contact surfaces between the films as described above, and the void layer on the outer side of the roll is thicker than that on the core side, even if the amount of air leakage between the films on the outer side of the roll increases during long-term storage, the thickness of the void layer will not be uneven, and the stress applied to the film will be uniform, thus eliminating adhesion problems.

[0084] As an embodiment of the present invention, from the perspective of preventing winding deviation during transportation and suppressing adhesion failure during long-term storage, it is preferable that X [μm] and Y [μm] satisfy the above formula (2) and formula (3).

[0085] (1.2) Void layer between thin films

[0086] (1.2.1) Methods for controlling the thickness of the void layer

[0087] The film roll of the present invention uses a gap layer that is thickened at the outer periphery of the roll by inhaling an appropriate amount of air, thereby relatively increasing the friction between the films at the periphery of the roll core, improving the effect of preventing winding deviation during transport and suppressing adhesion failure during long-term storage.

[0088] In addition, even if more air overflows from the outer part of the roll, the thickness deviation of the void layer of the entire film roll can be suppressed to a small extent, forming a uniform void layer between the films.

[0089] As examples of the above methods, one can exemplify methods such as using a contact roller to change the film contact pressure, and changing the winding tension, winding speed, and roller tilt angle.

[0090] The aforementioned contact rollers can be multiple, or they can be chrome-plated as a surface finish.

[0091] Alternatively, the aforementioned contact roller body can also be an elastic roller body or the like.

[0092] (1.2.2) Method for calculating the thickness of the void layer

[0093] Figure 3 It is a general diagram showing the positional relationship between the side of the film roll in the width direction and the imaging device.

[0094] like Figure 3 As shown, the imaging device (E) is positioned on the side of the film roll (30) wound around the core (R) in the width direction.

[0095] It should be noted that, Figure 3 In this context, TD represents the width direction of the film roll.

[0096] Below, an example of a method for photographing the side view of a thin film roll in the width direction using the aforementioned photographing device, and a method for calculating the void layer thickness, will be explained.

[0097] Using a part of the imaging device, namely the imaging unit (U), the side of the film roll in the width direction is photographed with any point (P) as the center, and image data is obtained for calculating the gap between the films.

[0098] Figure 4 This is an overview view of the side face when viewed from a plane perpendicular to the width direction of the film roll.

[0099] Here, as Figure 4 As shown, when the roll diameter from the core surface (S0) to the outermost film layer (S4) of the film roll is expressed as a percentage, the roll diameter of the core surface (S0) is 0%, and the roll diameter of the outermost film layer (S4) of the film roll is 100%.

[0100] When photographing the periphery of the roll core, focus on the area at 20% of the roll diameter (P). 20 Using the center as the focal point, take a picture of the side profile to obtain the image data.

[0101] It should be noted that when photographing the center of the roll, the position should be 50% of the roll diameter (P). 50 Using the 'P' as the center, take photos of this side profile. When taking photos of the outer perimeter of the roll, position the roll diameter is 80% (P). 80 Using the center as the focal point, take a picture of the side profile to obtain the image data.

[0102] Next, edge enhancement processing is performed on the acquired image data to obtain... Figure 5 The processing image shown is used to calculate the thickness of the void layer, which calculates the thickness of the void layer between adjacent films in the core periphery, the center of the roll, and the outer periphery of the roll on the width side of the film roll.

[0103] Since the thickness of the void layer between films is calculated in three regions—the periphery of the core, the center of the roll, and the outer periphery of the roll—before illustrating specific examples for calculating the thickness of the void layer, the concepts of the three regions—the periphery of the core, the center of the roll, and the outer periphery of the roll—will be explained first.

[0104] Figure 6 This is a simplified conceptual diagram illustrating a portion of the width-direction side surface of a film roll, used to explain the core periphery, the roll center, and the outer periphery.

[0105] exist Figure 6 In this process, when the film layer directly wound on the core (R) and adhered to the core surface (S0) (not shown) is designated as S1, and the outermost layer of the film roll is designated as S4, the area on the core side when the area from S1 to S4 is divided into three uniform areas is designated as the core periphery (A), the area on the outside of the roll is designated as the outer periphery (C), and the area between the core periphery (A) and the outer periphery (C) is designated as the roll center (B).

[0106] In addition, the thin film layer that forms the boundary between the core periphery (A) and the center of the roll (B) is S2, and the thin film layer that forms the boundary between the center of the roll (B) and the outer periphery (C) of the roll is S3.

[0107] As a specific example for calculating the thickness of the void layer around the core, the following calculation method can be cited.

[0108] (A specific example of how to calculate the thickness of the void layer)

[0109] For example, in calculating the thickness of the void layer around the core, the position (P) is used. 20 Centered on a point, images are taken of the side profile of the thin film roll along its width to obtain image data used to calculate the gaps between the films. Then, edge enhancement processing is performed on the acquired image data to obtain... Figure 5 The processing image shown is centered at P. 20Starting from the point on the outer side of the roll perpendicular to the film surface and located at the 100th layer, the length in the radial direction is measured, and the thickness X [μm] of the void layer is calculated using the following formula (A).

[0110] Equation (A) Thickness of the void layer X [μm] = [Radial length [μm] - (Average thickness of each thin film layer measured by a film thickness gauge [μm]) × (Number of layers)] ÷ (Number of layers)

[0111] It should be noted that the (number of layers) in the above formula is determined according to which layer the endpoint is located on when it is oriented towards the outer side of the roll perpendicular to the film surface. In the case of the 100th layer as described above, (number of layers) = 100.

[0112] In calculating the thickness of the void layer in the central part of the roll, in addition to taking the aforementioned position (P) 20 ) changed to location (P) 50 Except for the above description, the calculation of the thickness of the void layer at the outer periphery of the roll is performed in the same manner. 20 ) changed to location (P) 80 Except for ), all others are calculated in the same way as described above.

[0113] It should be noted that when taking a picture of the side of the film roll in the width direction with any point (P) as the center because the total length of the film roll is relatively short, if there are no 100 layers on the outside of the roll perpendicular to the film surface, for example, if there are only 70 layers, the point located at the 70th layer can be taken as the endpoint, the length in the radial direction can be measured, and the thickness X [μm] of the void layer can be calculated using the above formula (A).

[0114] As the film thickness gauge in the above formula (A), for example, the online delay / film thickness measuring device RE-200L2T-Rth+film thickness (manufactured by Otsuka Electronics (Co., Ltd., Japan) can be used).

[0115] (System structure of the shooting unit and shooting device)

[0116] The following structure was used as the shooting unit.

[0117] Figure 7 This is a schematic diagram of the internal structure of the imaging unit (U). Figure 7 In this context, S represents the measured surface (width-direction side face) of the thin film roll. It should be noted that... Figure 7 The main structural components are as follows.

[0118] <Structural components>

[0119] Total internal reflection mirror (60)

[0120] • Semi-reflective mirror (61)

[0121] • Telecentric lens (62) (MML1-HR130VI-35F: Moritex Ltd. (Japan), magnification ×1, WD130mm)

[0122] • High-brightness linear lighting (63) (LNSP2-100SW: manufactured by CCS)

[0123] Monochrome line sensor - camera (64) (RMSL8K39CL: manufactured by Nippon Electronics Co., Ltd., 8000 pixels with 3.5μm / pixel)

[0124] In addition, the system structure of the shooting device is as follows: Figure 8 The overview diagram is shown below.

[0125] 2. Method for manufacturing thin film rolls

[0126] The method for manufacturing a film roll of the present invention is a method for manufacturing a film roll without an embossing processing part. The method is characterized in that, when the thickness of the gap layer between the films adjacent to each other in the width direction side portion of the film roll is set as X [μm] and the thickness of the gap layer between the films adjacent to each other in the outer periphery portion of the roll is set as Y [μm], X and Y are adjusted to satisfy the relationship of the formula (1).

[0127] In the above-mentioned method for manufacturing film rolls, from the perspective of preventing winding deviation during transport and suppressing adhesion failure during long-term storage, it is preferable to adjust X [μm] and Y [μm] to satisfy Equation (2) and Equation (3).

[0128] In addition, from the perspective of preventing winding deviation during transport and suppressing adhesion failure during long-term storage, it is preferable to adjust the film contact pressure at the periphery of the core to the range of 6 to 55 [N / m], the film contact pressure at the center of the roll to the range of 4 to 40 [N / m], and the film contact pressure at the outer periphery of the roll to the range of 3 to 30 [N / m].

[0129] The thin film rolls of the present invention can be manufactured using common manufacturing methods such as blow molding, T-die molding, calendering, cutting, casting, emulsion molding, and hot pressing. However, from the perspective of suppressing coloring, foreign matter defects, and optical defects such as parting lines, solution casting and melt casting are preferred. In particular, solution casting is preferred because it improves the surface of the thin film.

[0130] (2.1) Solution casting film formation method

[0131] Figure 9This is a flowchart illustrating the manufacturing process of solution casting film deposition. Figure 10 This is a schematic diagram of an apparatus for manufacturing thin films using a solution casting method.

[0132] In the following solution casting film formation method, refer to Figure 9 and Figure 10 Please provide an explanation.

[0133] The method for manufacturing thin films using solution casting includes: a dopant preparation step [S1], a casting step [S2], a peeling step [S3], a shrinking step [S4], a first drying step [S5], a first stretching step [S6], a first cutting step [S7], a second stretching step [S8], a second cutting step [S9], a second drying step [S10], a third cutting step [S11], and a winding step [S12].

[0134] It should be noted that the above manufacturing method does not necessarily include both the first drying step [S5] and the second drying step [S10], as long as it includes at least one of the steps.

[0135] In addition, any cutting process that includes the first stretching process [S6], the second stretching process [S8], the first cutting process [S7], the second cutting process [S9], and the third cutting process [S11] is acceptable.

[0136] (2.1.1) Dopant preparation (stirring preparation) process [S1]

[0137] The following is an example of the dopant preparation process using a cyclic olefin resin (hereinafter also referred to as "COP") as a thermoplastic resin, as an embodiment of the present invention, but the present invention is not limited thereto.

[0138] exist Figure 9 In the dopant preparation (stirring preparation) process [S1], in Figure 10 In the stirring tank (1a) of the stirring device (1), at least resin and solvent are stirred to prepare a dopant cast on the support (3) (annular belt).

[0139] (solvent)

[0140] The solvent used is a mixture of good and bad solvents.

[0141] This process involves stirring and dissolving the COP, or other compounds as appropriate, in a solvent with a good solvent relative to the COP in a dissolving vessel to form a dopant, or mixing other compound solutions in the COP solution as appropriate to form a main solution, i.e., the dopant.

[0142] From the perspective of reducing the drying load after casting the dopant on the support, it is preferable to have a higher concentration of COP in the dopant. However, when the concentration is too high, the load during filtration of the dopant increases and the accuracy deteriorates. Therefore, it is necessary to balance the reduction of the drying load and the suppression of the load during filtration.

[0143] To take into account the above, the concentration of COP in the dopant is preferably in the range of 10 to 35% by mass, and more preferably in the range of 15 to 30% by mass.

[0144] In addition, the dopant preferably contains water in the range of 0.01 to 2% by mass.

[0145] One type of solvent or two or more solvents can be used in the doping process. However, in terms of production efficiency, it is preferable to use a mixture of good and bad solvents for COP. In terms of COP solubility, good solvents are preferred.

[0146] The preferred range for the mixing ratio of good solvent and bad solvent is that the good solvent is in the range of 70% to 98% by mass and the bad solvent is in the range of 2% to 30% by mass.

[0147] It should be noted that in this specification, "good solvent" for COP is defined as the solvent used to dissolve COP alone, and "bad solvent" for COP is defined as the solvent used to swell or not dissolve COP alone.

[0148] Therefore, good solvents and bad solvents vary according to the average degree of substitution of the above COP.

[0149] The good solvents used in this invention are not particularly limited, but examples include organohalogen compounds such as dichloromethane, dioxolane, acetone, methyl acetate, methyl acetoacetate, etc., with dichloromethane or methyl acetate being particularly preferred.

[0150] The unsuitable solvents used in this invention are not particularly limited, but methanol, ethanol, n-butanol, cyclohexane, cyclohexanone, etc. are preferred, for example.

[0151] In addition, the solvent used in the dissolution of COP is a solvent that is recycled from the film by drying in each process and reused.

[0152] The recycled solvent may also contain trace amounts of additives added to COP, such as plasticizers, UV absorbers, resins, monomer components, etc. Even if it contains the above-mentioned additives, it can be preferably reused, and it can also be purified and reused if necessary.

[0153] (Dissolution method)

[0154] As for the COP dissolution method mentioned above during the preparation of dopants, ordinary methods can be used.

[0155] Specifically, preferred methods include those performed at atmospheric pressure, those performed below the boiling point of the main solvent, and those performed under pressure above the boiling point of the main solvent. When heating and pressure are combined, heating can be performed at atmospheric pressure to above the boiling point.

[0156] In addition, to prevent the formation of gels or lumpy undissolved substances called "Mamako", it is preferable to heat and stir to dissolve the solvent at a temperature above the boiling point of the solvent under normal pressure and within the range where the solvent does not boil under pressure.

[0157] Alternatively, it is also preferable to use a method in which COP is mixed with a poor solvent to wet or swell it, and then a good solvent is added to dissolve it.

[0158] Pressurization can also be achieved by introducing inert gases such as nitrogen, or by heating to increase the vapor pressure of the solvent.

[0159] External heating is preferred, for example, because jacketed heating makes temperature control easier.

[0160] From the perspective of COP solubility, the method of adding solvent and heating at a higher temperature is preferred. However, when the heating temperature is too high, the required pressure increases and the productivity deteriorates.

[0161] The preferred heating temperature is in the range of 30 to 120°C, more preferably in the range of 60 to 110°C, and even more preferably in the range of 70 to 105°C.

[0162] In addition, the pressure is adjusted to a level that prevents the solvent from boiling at the set temperature.

[0163] Alternatively, a cooling dissolution method is preferred, which allows COP to be dissolved in solvents such as methyl acetate.

[0164] (filter)

[0165] Next, the COP solution (dopane in or after dissolution) is preferably filtered using a suitable filter material such as filter paper.

[0166] As a filter material, materials with lower absolute filtration accuracy are preferred in order to remove insoluble substances, but when the absolute filtration accuracy is too low, the filter material is prone to clogging.

[0167] Therefore, filter media with an absolute filtration accuracy of 0.008 mm or less are preferred, filter media in the range of 0.001 to 0.008 mm are more preferred, and filter media in the range of 0.003 to 0.006 mm are even more preferred.

[0168] There are no particular restrictions on the material of the filter media; ordinary filter media can be used. However, it is preferable to use plastic filter media such as polypropylene or Teflon (registered trademark) that do not shed fibers, or metal filter media such as stainless steel.

[0169] Filtration is preferred to remove or reduce impurities, especially bright spots, in the raw material COP.

[0170] A bright spot or foreign object refers to a point (foreign object) where light leaks from the opposite side when two polarizers are arranged in an orthogonal Nicol configuration with a thin film placed between them. Light is shone from one polarizer side and observed from the other. Preferably, the number of bright spots with a diameter of 0.01 mm or more is 200 / cm². 2 the following.

[0171] More preferably 100 pieces / cm 2 The preferred value is 50 units / m. 2 The preferred values ​​are 0 to 10 per cm. 2 the following.

[0172] In addition, there are fewer bright spots smaller than 0.01mm.

[0173] Dopant filtration can be carried out by ordinary methods, but the method of heating and filtering at a temperature above the boiling point of the solvent under normal pressure and within the range where the solvent does not boil under pressure is preferred because the increase in the pressure difference (called pressure difference) before and after filtration is small.

[0174] The preferred temperature is in the range of 30 to 120°C, more preferably in the range of 45 to 70°C, and even more preferably in the range of 45 to 55°C.

[0175] The preferred filter pressure is lower.

[0176] Specifically, it is preferably 1.6 MPa or less, more preferably 1.2 MPa or less, and even more preferably 1.0 MPa or less.

[0177] (2.1.2) Casting process [S2]

[0178] exist Figure 9 In the casting process [S2], the dopant prepared in the dopant preparation process [S1] is fed into the substrate through a conduit via a pressurized fixed gear pump or the like. Figure 10 The dopant is cast from the casting mold (2) to the casting position on the support (3) formed by the infinitely transferred rotating stainless steel annular belt, forming a cast film (5).

[0179] At this time, as long as the angle of the normal to the surface of the support (3) (the surface of the dopant) is within the range of 0 to 90°, the inclination of the casting mold (2) can be appropriately set, that is, the discharge direction of the dopant from the casting mold (2) to the support (3).

[0180] Then, the cast film (5) is heated / dried on the support (3) to evaporate the solvent until the cast film (5) can be peeled off from the support (3) by the peeling roller (4).

[0181] It should be noted that, in this invention, the cast film refers to the doped film cast from the opening portion described above.

[0182] The above evaporation is preferably carried out in an ambient gas environment within the range of 5 to 75°C.

[0183] Methods for evaporating the solvent include blowing hot air onto the upper surface of the cast film (5), and / or transferring heat from the back of the support (3) through the liquid, and transferring heat from the inside to the outside using radiant heat, etc. However, the method of transferring heat from the inside to the outside using radiant heat is preferred because of its high drying efficiency.

[0184] Alternatively, a combination of the above methods is preferred.

[0185] From a productivity perspective, the width of the casting is preferably 1.3m or more.

[0186] More preferably, it is in the range of 1.3 to 4.0 m.

[0187] As long as the width of the casting does not exceed 4.0m, no streaks will be generated during the manufacturing process, and the stability will be increased in the subsequent transportation process.

[0188] From the perspective of transportability and productivity, the preferred range is 1.3 to 3.0 m.

[0189] (Cast mold)

[0190] Casting molds include hanger molds and T-molds, which can be preferred.

[0191] In order to improve the uniformity of film thickness in the casting process, those skilled in the art can exemplify methods for controlling the slit gap (the front opening of the liquid outlet of the slit nozzle) of the casting die opening (the part of the casting die slit from which the dopant is discharged) in both solution casting and melt casting methods.

[0192] For example, when extruding a dopant with high viscosity (including melt), the aforementioned slit gap width difference will occur. To prevent this difference, multiple heating bolts are set in the width to control the slit gap.

[0193] However, this method has the problem that the number of heating bolts has a physical limit.

[0194] In addition, although there is a method to change the internal structure of the casting die in width to suppress the pressure variation in width that causes the aforementioned slit gap, the casting die must be replaced for each product, which results in wasted time and cost.

[0195] The casting mold is equipped with a mechanism for adjusting the width of the slit through which the dopant is discharged (when the resin is molten).

[0196] Preferably, the heating bolts of the casting mold are used to adjust the gap in the width of the slit for discharging the dopant, so that the thickness deviation of the film after discharge is within the range of 1.0 to 5.0% relative to the overall cast film, and the initial discharge film thickness of the cast film is controlled.

[0197] To improve the film formation rate of the thin film of the present invention, two or more of the above-mentioned casting molds can be provided on the support to divide the doping dose and form a multilayer.

[0198] Alternatively, a co-casting method, in which multiple dopants are simultaneously cast, can be preferred to obtain a laminated thin film roll.

[0199] Alternatively, to increase the film formation rate, two or more casting molds can be set on the support to divide the doping dose and form a multilayer.

[0200] (Support body)

[0201] The support (3) is preferably made of stainless steel strip or a roller formed by coating the surface of a casting, and is held by a pair of rollers (3a), a roller (3b) and a plurality of rollers located between the rollers.

[0202] In this case, the surface of the support is preferably a mirror.

[0203] One or both of the rollers (3a) and (3b) are provided with a drive device to provide tension to the support (3), thereby the support (3) is used in a tensioned state.

[0204] The surface temperature of the support (3) in the casting process (S2) is preferably within the range of -50°C to the boiling point of the solvent. The higher the temperature, the faster the casting film can dry.

[0205] The preferred support temperature is in the range of 0 to 55°C, and more preferably in the range of 22 to 50°C.

[0206] It should be noted that the temperature of the support can be uniform throughout or vary depending on its location.

[0207] The method of controlling the temperature of the support (3) is not particularly limited, including the method of blowing hot or cold air, and the method of contacting the rear side of the support with warm water.

[0208] Because using warm water allows for efficient heat transfer, the time required to maintain a constant temperature in the support is shorter, making it a preferred method.

[0209] When using hot air, it may be necessary to use air with a temperature higher than the target temperature.

[0210] (2.1.3) Stripping process [S3]

[0211] In this process, after the solvent is evaporated on the support (3) in the casting process [S2] until the cast film (5) becomes a peelable film strength and is dried and cured or cooled and solidified, the film is peeled off from the support (3) before the film wraps around the support (3) once.

[0212] That is, this process is to peel off the film after the solvent has evaporated on the support (3) at the peeling position.

[0213] At this point, from the perspectives of surface quality, moisture permeability, and peelability, it is preferable to peel the aforementioned film from the support within a range of 30 to 600 seconds.

[0214] In the peeling process [S3], the film is peeled off using a self-supporting peeling roller (4) (a roller that helps peel off the film).

[0215] The temperature at the peeling location on the support is preferably in the range of -50 to 40°C, more preferably in the range of 10 to 40°C, and most preferably in the range of 15 to 30°C.

[0216] (Residual solvent amount)

[0217] In the peeling process [S3], the amount of residual solvent on the film on the support (3) is adjusted appropriately according to the strength of the drying conditions and the length of the support (3). In the shrinking process [S4], the amount of residual solvent is greatly affected by the thickness of the film and the resin. Therefore, in the peeling process [S3] and the shrinking process [S4], there is a range that overlaps with the preferred range of residual solvent amount.

[0218] Although the amount of residual solvent in a film varies depending on its thickness, when there is too much residual solvent at the peel point (the location where the film is peeled from the support), the film may become too soft and difficult to peel, resulting in impaired flatness, or it may be prone to horizontal knots, dents, or vertical stripes due to peeling tension.

[0219] Conversely, if the amount of residual solvent is too small, part of the film may detach during transit.

[0220] From the above perspective, in order to exhibit good flatness, and considering both economy and speed and quality, it is desirable for the residual solvent content of the film to be in the range of 10-50% by mass.

[0221] As a method to increase the film formation rate (peeling with as much residual solvent as possible can increase the film formation rate), gel casting (gel casting) can be cited as an example, which can peel off even with a large amount of residual solvent.

[0222] The above methods include adding a poor solvent relative to COP to the dopant, gelling the cast film after casting the dopant, and peeling the cast film in a state containing a large amount of residual solvent by cooling the support.

[0223] In addition, there is a method of adding metal salts to the dopant.

[0224] As described above, by gelling and strengthening the cast film on the support, the film can be peeled off from the support as quickly as possible, thereby increasing the film formation rate.

[0225] The amount of residual solvent is defined by the following formula.

[0226] Formula: Residual solvent content [mass %] = {(M - N) / N} × 100

[0227] It should be noted that M in the above formula is the mass of the sample collected at any time during or after the manufacturing of the cast film or thin film, and N is the mass of M after heating it at 115°C for one hour.

[0228] (Peeling tension)

[0229] The peel tension when separating the support from the film is preferably below 300 N / m.

[0230] More preferably, the range is 196 to 245 N / m, but if wrinkles are easily generated during peeling, peeling is preferably performed with a tension of 190 N / m or less.

[0231] (2.1.4) Shrinkage process [S4]

[0232] The shrinkage process [S4] is a process that shrinks the film (F) in the width direction within the plane.

[0233] As a method to shrink the film (F), it can be carried out by, for example, increasing the film density by subjecting the film to high-temperature treatment without maintaining its width, applying tension to the film after it has been peeled from the support in the transport direction (Machine Direction, hereinafter also referred to as "MD direction") to stretch and shrink it in the width direction (TD direction) orthogonal to the MD direction within the film surface, and drastically reducing the amount of residual solvent in the film.

[0234] In this case, the film contracts in the width direction (traverse direction, also referred to below as "TD direction") orthogonal to the MD direction within the film plane.

[0235] The shrinkage process promotes entanglement between resin molecules (matrix molecules) in the thickness direction of the film. Therefore, for example, when manufacturing a polarizer, even when the film and the polarizer are bonded together with an adhesive, the adhesive can easily penetrate into the interior of the film through the entangled portion (cross-linked portion) of the matrix molecules.

[0236] As a result, the film can be firmly fixed to the polarizer via the adhesive, and the peel strength of the film relative to the polarizer can be improved.

[0237] In other words, it can ensure good adhesion between the thin film and the polarizer.

[0238] (Definition of shrinkage rate)

[0239] In this invention, the shrinkage rate is defined by the following formula.

[0240] Formula: Shrinkage rate [%] = Film width at the end of the shrinkage process [mm] / Film width at the beginning of the shrinkage process [mm] × 100

[0241] Here, in the shrinkage process [S4], if the shrinkage rate of the film is too small, the effect of promoting entanglement between matrix molecules is insufficient; if it is too large, the production efficiency of the film (stretched film) may decrease.

[0242] Therefore, the shrinkage rate of the film in the shrinkage process [S4] is preferably in the range of 1 to 40%, and more preferably in the range of 5 to 20%.

[0243] (Methods for measuring and calculating shrinkage rate)

[0244] The width of the film can be measured using the LS-9000 manufactured by Keyence Ltd. (Japan).

[0245] It should be noted that the shrinkage rate of the film of the present invention is obtained by substituting the average value of the film width measured by the above measuring device for five minutes (300 seconds) at one second into the above formula. However, it is not necessarily limited to the above method. For example, the value of the film width read by the ruler can also be used as the film width and substituted into the above formula.

[0246] (2.1.5) First drying process [S5]

[0247] In the first drying step [S5], the film (F) is heated on the support by the drying device (6), thereby causing the solvent to evaporate and dry.

[0248] exist Figure 10 Inside the drying apparatus (6), a plurality of transport rollers configured in a serrated shape when viewed from the side are used to transport the film (F) and during this period the film (F) is dried.

[0249] The drying method in the drying device (6) is not particularly limited. Hot air, infrared rays, heating rollers, microwaves, etc. are usually used to dry the film (F). However, from a simplification point of view, the method of using hot air to dry the film (F) is preferred.

[0250] Alternatively, a combination of the above methods is preferred.

[0251] It should be noted that the first drying step [S5] can be performed as needed.

[0252] When the film is thin, it dries quickly, but drying too quickly can damage the flatness of the finished film.

[0253] When drying films at high temperatures, the amount of residual solvent before drying needs to be considered. By keeping the amount of residual solvent low, malfunctions caused by solvent bubbling can be prevented.

[0254] The residual solvent content before the first drying step [S5] is preferably less than 30% by mass, and the entire drying process is carried out in the range of approximately 30 to 250°C.

[0255] It is particularly preferred to dry in the range of 35 to 200°C, and it is preferable to increase the drying temperature in stages.

[0256] Film drying is usually carried out by roller drying (a method in which the film is alternately passed through a large number of rollers arranged on the upper and lower sides for drying) or by conveying the film and drying it using a tenter frame.

[0257] When using a tenter frame stretching device in film drying, it is preferable to use a device in the stretching process described later that utilizes the left and right clamping method of the tenter frame stretching device and can independently control the clamping length (distance from the start of clamping to the end of clamping) of the film from left to right.

[0258] In addition, during the stretching process, it is preferable to intentionally create zones with different temperatures to improve flatness.

[0259] In addition, it is preferable to set up neutral zones between different temperature zones so that the zones do not interfere with each other.

[0260] (2.1.6) First stretching process [S6]

[0261] The first stretching process [S6] can be a process of stretching the film (F) only in the MD direction within the film surface, a process of stretching the film only in the TD direction, or a process of stretching in both the MD and TD directions, or obliquely upwards.

[0262] In addition, the stretching direction is not limited, but from the perspective of obtaining a wide film, it is preferable to have a process that includes stretching in at least the width direction.

[0263] The above stretching is performed by the stretching device (7).

[0264] (Stretching method)

[0265] Examples of stretching methods include: setting a difference in the circumferential speed of the rollers and stretching in the transport direction (the length direction of the film, the film forming direction, the casting direction, the longitudinal direction, and the MD direction) (longitudinal stretching); fixing the two sides of the film (F) with clamps or the like and stretching in the width direction (the direction orthogonal to the film surface, the width direction of the film, the transverse direction, and the TD direction) (transverse stretching); performing longitudinal stretching and transverse stretching sequentially (successive biaxial stretching); and performing longitudinal stretching and transverse stretching simultaneously (simultaneous biaxial stretching). In the transverse stretching and simultaneous biaxial stretching (including oblique stretching) of the above methods, a tenter frame stretching device is used.

[0266] The stretching device of a tenter frame is a device that uses clamps to hold the two ends of the film in the width direction, so that the clamps move with the film and widen the gap, thereby stretching the film.

[0267] Among the above methods, in order to improve the performance / productivity, flatness and dimensional stability of the film, it is preferable to use a tenter frame stretching device, also known as a tenter frame method.

[0268] Furthermore, in the case of the so-called tenter frame method, when the fabric clamping part is driven in a linear drive manner, smooth stretching can be achieved and the risk of breakage can be reduced, so it is preferred.

[0269] In the film forming process, the width maintenance or lateral stretching mentioned above is preferably performed by a tenter frame stretching device, which can be a pin plate tenter frame or a fabric clip tenter frame.

[0270] It should be noted that, in addition to stretching, drying can also be performed inside the stretching device (7).

[0271] (Stretch ratio)

[0272] To ensure high phase difference, wide width, and to promote adhesive penetration when bonding with the polarizer, it is preferable to stretch the film at a high ratio during the stretching process.

[0273] However, when the stretching ratio is too high, cracks may be generated in the film due to tensile stress, or the entanglement between matrix molecules that maintain the strength of the film may disintegrate, making the film fragile.

[0274] Therefore, the stretching ratio in the stretching process is preferably in the range of 1.1 to 5.0 times, and more preferably in the range of 1.3 to 3.0 times.

[0275] It should be noted that the "stretch ratio" mentioned in this invention refers to the ratio of the area of ​​the film after stretching to the area of ​​the film before stretching [%].

[0276] That is, the "stretch ratio" in the above stretching process is preferably the total stretch ratio formed by stretching the film in the longitudinal (length) direction and the transverse (width) direction, which is in the range of 1.1 to 5.0 times in terms of area ratio, and more preferably in the range of 1.3 to 3.0 times.

[0277] It should be noted that, in the case of multiple stretching operations, the stretching at the highest magnification rate with the highest risk of matrix molecule dissociation during the last stretching operation is preferred.

[0278] For example in Figure 9 In the process, it is preferable to perform the stretching at the highest ratio in the second stretching step.

[0279] In this case, because the matrix molecules can be firmly entangled before the highest stretching ratio, the dissociation of matrix molecules can be suppressed even when the stretching ratio is highest, thus inhibiting condensation breakdown.

[0280] (Stretching device of tenter frame)

[0281] Below, refer to Figure 11 , Figure 12 , Figure 13 and Figure 14The following explanation will be based on the case where the tenter frame tensioning device is used as the tensioning device (7).

[0282] Figure 11 It is a top view schematically showing the internal structure of the tenter frame stretching device, and a cross-sectional view of the plane of the tenter frame stretching device perpendicular to the film surface as viewed from above.

[0283] Figure 12 This indicates the state after the cover of the tenter frame stretching device has been removed. The cover is represented by a double-dotted line.

[0284] Figure 13 This is an overview diagram of the nozzle and heater arrangement in the three zones inside the tenter frame when viewed from the front.

[0285] like Figure 13 As shown, although the infrared (IR) heater is only positioned above the nozzle so that the film will not come into contact with the infrared (IR) heater when the film breaks, the infrared (IR) heater can concentrate the radiant energy generated by the infrared (IR) heater in a smaller area because the infrared (IR) heater is close to the film. Therefore, the infrared (IR) heater should be placed as close to the film as possible without affecting the stretching action of the clip.

[0286] It should be noted that, in Figure 13 The text mainly refers to the heat treatment from the central nozzle (105). In this embodiment, the heat treatment performed by the end nozzle (104) is not performed, but in this embodiment, the heat treatment can be combined.

[0287] like Figure 14 As shown, during heat treatment, the radiant energy of the infrared (IR) heater protruding from the nozzle gap can be propagated to the thin film without waste.

[0288] like Figure 11 As shown, infrared (IR) heaters can be configured in rows to heat the entire width of the film even before stretching.

[0289] It should be noted that the heater can also be configured in a serrated shape along its length.

[0290] The tenter frame stretching device (40) has a large number of clamps (42) at both ends of the film (F) in the width direction, and the clamps (42) are mounted on the ring chain (48) at constant intervals.

[0291] The annular chain (48) is arranged on both sides through the membrane (F), and is respectively mounted between the driving sprocket (50) on the inlet side and the driven sprocket (52) on the outlet side.

[0292] The drive sprocket (50) is connected to a motor (not shown), which drives the drive sprocket (50) to rotate.

[0293] As a result, the ring chain (48) moves around between the driving sprocket (50) and the driven sprocket (52), so the clip (42) mounted on the ring chain (48) moves around.

[0294] A guide rail (54) is provided between the driving sprocket (50) and the driven sprocket (52) to guide the ring chain (48) (or the clip (42)).

[0295] The guide rails (54) are arranged on both sides through the film (F), and the spacing between the guide rails (54) is configured such that the downstream side is wider than the upstream side in the transport direction of the film (F).

[0296] Therefore, as the clamps (42) move around, the gap between the clamps (42) increases, so the film (F) held by the clamps (42) can be stretched laterally in the width direction.

[0297] Open parts (56) are installed on the driving sprocket (50) and the driven sprocket (52).

[0298] The opening component (56) is a device that moves the baffle (not shown) of the clamp (42) described later from the clamping position to the open position. The clamping and opening actions of the film (F) are automatically performed by the opening component (56).

[0299] By the way, if Figure 11 , Figure 12 and Figure 14 As shown, the interior of the tenter frame stretching device (40) is provided with a preheating zone, a (transverse) stretching zone and a heat-fixing zone.

[0300] The zones are separated from each other by windbreaks (not shown).

[0301] In addition, hot air is supplied to the membrane (F) from above or below, or from both above and below, within each zone.

[0302] Hot air is blown out uniformly across the width of the film (F) at a specified temperature in each zone.

[0303] Thus, the interior of each zone is controlled to the desired temperature. The following is an explanation of each zone.

[0304] The preheating zone is the zone where the film (F) is preheated. The spacing of the clips (42) is not increased, and the film (F) is heated.

[0305] The preheated film (F) moves towards the (lateral) stretching zone in the preheating zone.

[0306] The (lateral) stretching zone is the zone in which the film (F) is stretched (laterally) in the width direction by increasing the spacing of the clips (42).

[0307] The stretching ratio of the (transverse) stretching treatment is preferably in the range of 1.0 to 2.5 times, more preferably in the range of 1.05 to 2.3 times, and even more preferably in the range of 1.1 to 2 times.

[0308] In the transverse stretching zone, the transversely stretched film (F) moves toward the heat-fixing zone.

[0309] It should be noted that in this embodiment, the interior of the tenter frame stretching device (40) is divided into a preheating zone, a (transverse) stretching zone, and a heat-fixing zone, but the type and configuration of the zones are not limited to this. For example, a cooling zone for cooling the film (F) may be provided after the (transverse) stretching zone.

[0310] Alternatively, a heat-relieving zone can be provided within the heat-fixed zone.

[0311] It should be noted that in this embodiment, the tenter frame stretching device (40) only performs (transverse) stretching, but it can also perform stretching in the longitudinal direction at the same time.

[0312] In this case, when the clamps (42) move, it is only necessary to change the spacing of the clamps (42) (the interval between the clamps (42) in the transport direction).

[0313] As a mechanism for changing the spacing of the clips (42), for example, a pantograph mechanism or a linear guide mechanism can be used.

[0314] (Heat treatment time)

[0315] The stretching device of a tenter frame is usually divided into multiple zones, such as... Figure 11 , Figure 12 and Figure 14 As shown, the device includes a preheating zone for heating the film, a transverse stretching zone for stretching the film in the transverse direction, a heat-fixing zone for crystallizing the film, and a mitigation zone for relieving thermal stress on the film.

[0316] (Furnace temperature)

[0317] Typically, the furnace temperature is preferably in the range of 120 to 200°C, and more preferably in the range of 120 to 180°C.

[0318] Here, "furnace temperature" refers to the temperature measured 100 mm above the center of the film before stretching, within the stretching zone of the tenter frame described later. A =100mm), defined as the temperature after measuring the temperature values ​​at one minute intervals for one hour and calculating their average value.

[0319] Typically, the furnace temperature is preferably in the range of 120 to 200°C, and more preferably in the range of 120 to 180°C.

[0320] Here, when multiple partitions form a temperature gradient along their length, the heat treatment partition is taken as the object.

[0321] Furthermore, the furnace temperature differs when heat treatment is performed in the stretching zone versus when no heat treatment is performed. However, when heat treatment is performed in the stretching zone, the furnace temperature refers to the furnace temperature of the stretching zone before heat treatment.

[0322] (Residual solvent amount)

[0323] The amount of residual solvent in the film during stretching is preferably 20% by mass or less, and more preferably 15% by mass or less.

[0324] (2.1.7) First cutting process [S7]

[0325] In the first cutting process [S7], the cutting section (8) formed by the scraper cuts both ends of the film (F) in the width direction after it has been stretched by the first stretching process [S6].

[0326] The remaining portion after cutting both ends of the film (F) constitutes the product part of the film product.

[0327] On the other hand, the portion cut from the film (F) can be recycled and reused as part of the raw materials in the film formation process.

[0328] (2.1.8) Second stretching process [S8]

[0329] In the second stretching process [S8], the film (F) is stretched by the stretching device (9) in the same manner as in the first stretching process [S6].

[0330] As a stretching method at this time, in order to improve the performance / productivity, flatness and dimensional stability of the film, it is preferable to use a stretching method with a circumferential speed difference of rollers and stretching in the transport direction (MD direction), or a tenter method in which the two sides of the film (F) are fixed by clips or the like and stretching is performed in the width direction (TD direction).

[0331] It should be noted that, in addition to stretching, drying can also be performed inside the stretching device (9).

[0332] (2.1.9) Second cutting process [S9]

[0333] In the second cutting process [S9], the same as in the first cutting process [S7], the cutting section (10) formed by the scraper cuts both ends of the film (F) in the width direction after film formation.

[0334] It should be noted that the clamping portions at both ends of the film are usually cut off because the film is deformed and cannot be used as a product.

[0335] The material will be recycled and reused if it does not deteriorate due to heat.

[0336] In the film (F), the remaining portion after cutting off both ends constitutes the product part of the film product.

[0337] On the other hand, the portion cut from the film (F) is recycled and reused as part of the raw materials in the film formation process.

[0338] (2.1.10) Second drying process [S10]

[0339] In the second drying process [S10], the film (F) is dried by the drying device (11), just like in the first drying process [S5].

[0340] Inside the drying apparatus (11), a film (F) is transported by a plurality of transport rollers configured in a serrated shape when viewed from the side, during which the film (F) is dried.

[0341] The drying method in the drying device (6) is not particularly limited, and can usually be exemplified by hot air, infrared rays, heating rollers, and microwaves.

[0342] Among the above drying methods, the method of drying the film (F) using hot air is preferred in terms of simplicity.

[0343] It should be noted that the second drying process [S10] can be carried out as needed.

[0344] (2.1.11) Third cutting process [S11]

[0345] In the third cutting process [S11], the same as the first cutting process [S7] and the second cutting process [S9], the cutting section (12) formed by the scraper cuts both ends of the film (F) in the width direction after film formation.

[0346] The remaining portion after cutting both ends of the film (F) constitutes the product part of the film product.

[0347] On the other hand, the portion cut from the film (F) is recycled and reused as part of the raw materials in the film formation process.

[0348] (2.1.12) Winding process [S12]

[0349] Finally, in the winding process [S12], the film (F) is wound by the winding device (13) to obtain a film roll.

[0350] That is, in the winding process, a film roll is manufactured by transporting the film (F) and winding it onto the core.

[0351] The preferred range for the initial tension during the winding process is 20–300 N / m.

[0352] Figure 15 This is a schematic diagram showing the process of winding the film and a cross-sectional view of the film roll of the present invention after winding.

[0353] Preferably, when winding the film (F), for example, as Figure 15 The contact roller body (33) is set as shown, and the film contact pressure is appropriately changed in order to form the desired void layer.

[0354] exist Figure 15 In the process, the film (31) after film formation is wound into a film roll (30) by the roller (32) and the contact roller (33).

[0355] (Residual solvent amount)

[0356] More specifically, the process of winding a film by a winding device (12) after the residual solvent content in the film is less than 2% by mass can obtain a film with good dimensional stability by making the residual solvent content less than 0.4% by mass.

[0357] It is particularly preferred that the residual solvent content be in the range of 0.00 to 0.20% by mass when the winding is performed.

[0358] (Winding method)

[0359] The winding method for the film (F) can use a commonly used winding machine, which has methods for controlling tension such as constant torque method, constant tension method, conical tension method, and programmed tension control method with constant internal stress. The above methods can be used separately.

[0360] Before winding, the ends are cut off along the width of the product. To prevent sticking and scratches during winding, surface modification treatment can also be applied to both ends of the film.

[0361] (After winding)

[0362] The film roll of the present invention is preferably a long strip film, specifically, a film roll in the range of about 100 to 10,000 m, and is usually provided in roll form.

[0363] (2.2) Manufacturing process of thin film rolls based on melt casting film formation method

[0364] The thin film of the present invention can also be formed by melt casting.

[0365] "Melting film formation method" refers to a method of heating and melting a composition containing thermoplastic resin and the above-mentioned additives until it reaches a temperature that exhibits fluidity, and then allowing the melt containing the fluid thermoplastic resin to flow out.

[0366] As a molding method involving heating and melting, it can be specifically divided into melt extrusion molding, stamping molding, blow molding, injection molding, blow molding, stretch molding, etc.

[0367] Among the above molding methods, melt extrusion is preferred in terms of mechanical strength and surface precision.

[0368] Figure 16 This is a flowchart illustrating the manufacturing process of the melt casting film method.

[0369] in addition, Figure 17 This is an overview diagram of an apparatus for manufacturing thin films using the melt casting method.

[0370] Below, in the solution casting film formation method, refer to Figure 16 and Figure 17 Please provide an explanation.

[0371] The manufacturing method of a thin film roll based on melt casting includes: an extrusion process [M1], a casting / forming process [M2], a first stretching process [M3], a first cutting process [M4], a second stretching process [M5], a second cutting process [M6], and a winding process [M7].

[0372] It should be noted that the above manufacturing method does not necessarily include both the first stretching process [M3] and the second stretching process [M5], as long as it includes at least one of the processes.

[0373] Similarly, the first cutting process [M4] and the second cutting process [M6] can both be completed by including at least one of them.

[0374] (2.2.1) Extrusion process [M1]

[0375] In the extrusion process [M1], resin is melted and extruded using an extruder (14) and formed on a casting roller (16).

[0376] Details of the resins that can be used in this invention will be described later.

[0377] In addition, the resin is preferably pre-mixed for granulation.

[0378] Granulation can be performed using known methods.

[0379] For example, the dry resin, plasticizer and other additives are supplied to the extruder by the feeding device, and the mixture is compounded using a single-shaft or twin-shaft extruder. The mixture is then extruded from the casting die (15) into strands, cooled by water or air and cut, thereby enabling granulation.

[0380] The additives can be mixed into the resin before being fed to the extruder, or the additives and resin can be supplied to the extruder by separate feeding devices.

[0381] In addition, small amounts of additives such as particles and antioxidants are preferably pre-mixed into the resin to ensure uniform mixing.

[0382] When feeding pellets from the feed hopper into the extruder, it is preferable to do so in a dry, vacuum, reduced pressure, or inert gas environment to prevent oxidative decomposition, etc.

[0383] Extrusion is preferably performed at the lowest possible temperature for granulation to suppress shear forces and prevent resin degradation (such as molecular weight reduction, coloring, and gel formation).

[0384] For example, in the case of a twin-screw extruder, it is preferable to use a deep-groove screw that rotates in the same direction.

[0385] Based on the uniformity of the mixing, the interlocking type is preferred.

[0386] When the resin / granules are melted, it is preferable to filter them using a disc filter or similar device to remove foreign matter.

[0387] Thin film formation is performed using the granules obtained as described above.

[0388] Of course, granulation can also be skipped, and the raw material resin (powder, etc.) can be directly fed into the extruder by the feeding device to form a film directly.

[0389] (2.2.2) Casting / forming process [M2]

[0390] In the casting / forming process [M2], the resin / granules molten in the extrusion process are cast into a thin film through a conduit via a pressure-fixed gear pump or the like, and the molten resin / granules are cast from the casting mold (15) to the casting position on the infinitely transferable rotary-driven stainless steel annular casting roller (16).

[0391] Then, the molten resin / granules after casting are molded on the casting roller (16) to form a cast film (18).

[0392] The inclination of the casting mold (15), that is, the discharge direction of the molten resin / granules from the casting mold (15) to the support (16), can be appropriately set as long as the angle relative to the normal of the surface of the casting roller (16) (the surface where the molten resin / granules are cast) is within the range of 0 to 90°.

[0393] The contact roller (16a), the cooling roller (17) of the auxiliary casting roller (16) can also be used alone or in combination to form a film (F).

[0394] (2.2.3) First stretching process [M3]

[0395] In the first stretching process [M3], the film (F) is stretched by the stretching device (19).

[0396] As a stretching method at this time, in order to improve the performance / productivity, flatness and dimensional stability of the film, it is preferable to use a stretching method with a circumferential speed difference of rollers and stretching in the MD direction, or a tenter method in which the two sides of the film (F) are fixed by clamps or the like and stretching is performed in the TD direction.

[0397] It should be noted that, in addition to stretching, drying can also be performed in the stretching device (19).

[0398] It should be noted that the descriptions of the tenter frame stretching device, heat treatment time, furnace temperature, stretching temperature, temperature inside the stretching furnace, and residual solvent amount are omitted because they are repeated in the first stretching step [S6] of the film roll manufacturing process based on solution casting film formation.

[0399] (2.2.4) First cutting process [M4]

[0400] In the first cutting process [M4], the cutting section (20) formed by the scraper cuts both ends of the film (F) in the width direction after film formation.

[0401] In the film (F), the remaining portion after cutting off both ends constitutes the product part of the film product.

[0402] On the other hand, the portion cut from the film (F) can be recycled and reused as part of the raw materials in the film formation process.

[0403] (2.2.5) Second stretching process [M5]

[0404] In the second stretching process [M5], the film (F) is stretched by the stretching device (21), just like in the first stretching process [M3].

[0405] As a stretching method at this time, in order to improve the performance / productivity, flatness and dimensional stability of the film, it is preferable to use a stretching method with a circumferential speed difference of rollers and stretching in the MD direction, or a tenter method in which the two sides of the film (F) are fixed by clamps or the like and stretching is performed in the TD direction.

[0406] It should be noted that, in addition to stretching, drying can also be performed inside the stretching device (21).

[0407] (2.2.6) Second cutting process [M6]

[0408] In the second cutting process [M6], the same as in the first cutting process [M4], the cutting section (22) formed by the scraper cuts both ends of the film (F) in the width direction after film formation.

[0409] In the film (F), the remaining portion after cutting off both ends constitutes the product part of the film product.

[0410] On the other hand, the portion cut from the film (F) can be recycled and reused as part of the raw materials in the film formation process.

[0411] (2.2.7) Winding process [M7]

[0412] Finally, in the winding process [M7], the film (F) is wound by the winding device (23) to obtain a film roll.

[0413] That is, in the winding process [M7], the film (F) is transported and wound onto the core, thereby manufacturing the film roll.

[0414] The winding method for the film (F) can use a commonly used winding machine, which has tension control methods such as constant torque method, constant tension method, conical tension method, and programmed tension control method with constant internal stress. These methods can be used separately.

[0415] 3. Resin constituting the film

[0416] (3.1) Thermoplastic resin

[0417] The thermoplastic resin material used as the film of the present invention is not limited as long as it can be processed as a film roll after film formation.

[0418] As thermoplastic resins used for polarizing applications, cellulose ester resins such as triacetyl cellulose (TAC), cellulose acetate propionate (CAP), and diacetyl cellulose (DAC) or cyclic olefin resins such as cyclic olefin resins (hereinafter also referred to as "COP"), polypropylene resins such as polypropylene (PP), acrylic resins such as polymethyl methacrylate (PMMA), and polyester resins such as polyethylene terephthalate (PET) can be used.

[0419] However, COP is preferred due to its ease of control over stretchability and crystallinity, as well as its ability to easily penetrate the adhesive and ensure better adhesion to the polarizer.

[0420] It should be noted that the above-mentioned films can also undergo surface modification treatment after manufacturing.

[0421] Furthermore, the effects of this invention are even more valuable in the field of thin films.

[0422] The thickness of the film is preferably in the range of 5 to 80 μm, more preferably in the range of 10 to 65 μm, and even more preferably in the range of 10 to 45 μm.

[0423] When the thickness of the film is greater than 5 μm, the rigidity of the film roll increases, making it easier to maintain the roll shape.

[0424] When the thickness of the film is below 80μm, the mass will not increase excessively, and it is easy to manufacture long strips of film.

[0425] (3.1.1) Cycloolefin resins

[0426] The cyclic olefin resin contained in the film roll of the present invention is preferably a polymer of cyclic olefin monomers or a copolymer of cyclic olefin monomers and other comonomers.

[0427] As a cyclic olefin monomer, a cyclic olefin monomer having a norbornene skeleton is preferred, and a cyclic olefin monomer having a structure represented by the following general formula (A-1) or (A-2) is more preferred.

[0428] 1

[0429] General formula (A-1)

[0430]

[0431] In general formula (A-1), R 1 ~R 4 Each can be used independently to represent a hydrogen atom, a hydrocarbon group with 1 to 30 carbon atoms, or a polar group. P represents an integer from 0 to 2. However, R... 1 ~R 4 Not all of them simultaneously represent hydrogen atoms, R 1 With R2 R does not simultaneously represent hydrogen atoms 3 With R 4 They do not both represent hydrogen atoms.

[0432] In general formula (A-1), as R 1 ~R 4 The hydrocarbon group represented has 1 to 30 carbon atoms, preferably a hydrocarbon group with 1 to 10 carbon atoms, and more preferably a hydrocarbon group with 1 to 5 carbon atoms.

[0433] The hydrocarbon group having 1 to 30 carbon atoms may also have a linking group containing halogen atoms, oxygen atoms, nitrogen atoms, sulfur atoms, or silicon atoms.

[0434] Examples of the linking groups mentioned above include divalent polar groups such as carbonyl, imino, ether, silyl ether, and thioether.

[0435] Examples of hydrocarbon groups having 1 to 30 carbon atoms include methyl, ethyl, propyl, and butyl.

[0436] In general formula (A-1), R 1 ~R 4 Examples of polar groups include carboxyl, hydroxyl, alkoxy, alkoxycarbonyl, aryloxycarbonyl, amino, amide, and cyano.

[0437] Among them, carboxyl, hydroxy, alkoxycarbonyl and aryloxycarbonyl are preferred. From the perspective of ensuring solubility when the solution forms a film, alkoxycarbonyl and aryloxycarbonyl are preferred.

[0438] From the perspective of improving the heat resistance of the film, p in the general formula (A-1) is preferably either 1 or 2.

[0439] This is because when p is 1 or 2, the resulting polymer volume increases, and the glass transition temperature is more likely to increase.

[0440] 2

[0441] General formula (A-2)

[0442]

[0443] In general formula (A-2), R 5 R represents a hydrogen atom, a hydrocarbon group having 1 to 5 carbon atoms, or an alkylsilyl group having 1 to 5 carbon atoms. 6 It represents a carboxyl, hydroxyl, alkoxycarbonyl, aryloxycarbonyl, amino, amide, cyano, or halogen atom (fluorine, chlorine, bromine, or iodine). P represents an integer from 0 to 2.

[0444] R in general formula (A-2) 5Preferably, it represents a hydrocarbon group having 1 to 5 carbon atoms, and more preferably, it represents a hydrocarbon group having 1 to 3 carbon atoms.

[0445] R in general formula (A-2) 6 The preferred groups are carboxyl, hydroxyl, alkoxycarbonyl, and aryloxycarbonyl. From the perspective of ensuring solubility when the solution forms a film, alkoxycarbonyl and aryloxycarbonyl are more preferred.

[0446] From the perspective of improving the heat resistance of the film, p in the general formula (A-2) preferably represents 1 or 2.

[0447] This is because when p represents 1 or 2, the resulting polymer volume increases, and the glass transition temperature is more easily increased.

[0448] From the perspective of improving solubility in organic solvents, cyclic olefin monomers having a structure represented by general formula (A-2) are preferred.

[0449] Organic compounds typically reduce crystallinity by disrupting symmetry, thereby increasing their solubility in organic solvents.

[0450] R in general formula (A-2) 5 and R 6 The cyclic carbon atom is replaced only on one side of the symmetry axis of the molecule, so the symmetry of the molecule is low. That is, because the cyclic olefin monomer with the structure represented by the general formula (A-2) has high solubility, it is suitable for the manufacture of thin films by solution casting.

[0451] The proportion of cycloolefin monomers having a structure represented by general formula (A-2) in the polymer of cycloolefin monomers relative to the total amount of all cycloolefin monomers constituting the cycloolefin resin may be, for example, 70 mol% or more, preferably 80 mol% or more, and more preferably 100 mol%.

[0452] When the resin contains a certain number or more cyclic olefin monomers with a structure represented by the general formula (A-2), the orientation of the resin is enhanced, so the phase difference (retardation) value is easily increased.

[0453] Below, specific examples of cyclic olefin monomers having a structure represented by general formula (A-1) are shown as compounds 1 to 14, and specific examples of cyclic olefin monomers having a structure represented by general formula (A-2) are shown as compounds 15 to 34.

[0454] Transformation 3

[0455]

[0456] Examples of comonomers that can copolymerize with cyclic olefin monomers include: comonomers that can undergo ring-opening copolymerization with cyclic olefin monomers, and comonomers that can undergo addition copolymerization with cyclic olefin monomers.

[0457] Examples of comonomers that can undergo ring-opening copolymerization include cycloolefins such as cyclobutene, cyclopentene, cycloheptene, cyclooctene, and dicyclopentadiene.

[0458] Examples of addit-copolymerizable comonomers include compounds containing unsaturated double bonds, vinyl cyclic hydrocarbon monomers, and (meth)acrylates.

[0459] Examples of compounds containing unsaturated double bonds include olefins having 2 to 12 carbon atoms (preferably 2 to 8), such as ethylene, propylene, and butene.

[0460] Examples of vinyl cyclopentene monomers include vinylcyclopentene monomers such as 4-vinylcyclopentene and 2-methyl-4-isopropenylcyclopentene.

[0461] 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.

[0462] The proportion of cyclic olefin monomers in the copolymer of cyclic olefin monomers and copolymeric monomers can be, for example, in the range of 20 to 80 mol%, preferably in the range of 30 to 70 mol%, relative to the total number of monomers constituting the copolymer.

[0463] As described above, cyclic olefin resins are polymers obtained by polymerizing or copolymerizing cyclic olefin monomers having a norbornene skeleton, preferably by polymerizing or copolymerizing cyclic olefin monomers having a structure represented by general formula (A-1) or (A-2), including polymers as follows (1) to (7) in this example.

[0464] (1) Ring-opening polymers of cyclic olefin monomers

[0465] (2) Ring-opening copolymers of cyclic olefin monomers and comonomers that can be ring-opened copolymerized with them.

[0466] (3) The hydride of the ring-opening (co)polymer of (1) or (2) above

[0467] (4) After cyclizing the ring-opening (co)polymer of (1) or (2) above by the Fried-Krawc reaction, the (co)polymer after adding hydrogen

[0468] (5) Saturated copolymers of cyclic olefin monomers and compounds containing unsaturated double bonds

[0469] (6) Addition copolymers of cyclic olefin monomers and ethylene cyclic hydrocarbon monomers and their hydrides

[0470] (7) Alternating copolymers of cyclic olefin monomers and (meth)acrylates

[0471] The polymers described in (1) to (7) above can all be obtained by known methods, such as those described in Japanese Patent Application Publication No. 2008-107534 and Japanese Patent Application Publication No. 2005-227606.

[0472] For example, the catalyst or solvent used in the ring-opening copolymerization in (2) above can be the catalyst or solvent described in paragraphs 0019 to 0024 of Japanese Patent Application Publication No. 2008-107534.

[0473] The catalyst used in the hydrides described in (3) and (6) above can be, for example, the catalyst described in paragraphs 0025 to 0028 of Japanese Patent Application Publication No. 2008-107534.

[0474] The acidic compound used in the Fried-Krawtz reaction described above (4) can be, for example, the acidic compound described in paragraph 0029 of Japanese Patent Application Publication No. 2008-107534.

[0475] The catalyst used in the addition polymerization of (5) to (7) above can be, for example, the catalyst described in paragraphs 0058 to 0063 of Japanese Patent Application Publication No. 2005-227606.

[0476] The alternating copolymerization reaction described in (7) above can be carried out, for example, by the method described in paragraphs 0071 and 0072 of Japanese Patent Application Publication No. 2005-227606.

[0477] Among them, the polymers of (1) to (3) and (5) above are preferred, and the polymers of (3) and (5) above are even more preferred.

[0478] That is, in terms of increasing the glass transition temperature of the obtained cyclic olefin resin and increasing the light transmittance, the cyclic olefin resin preferably includes at least one of the structural unit represented by the following general formula (B-1) and the structural unit represented by the following general formula (B-2), more preferably it includes only the structural unit represented by general formula (B-2), or includes both the structural unit represented by general formula (B-1) and the structural unit represented by general formula (B-2).

[0479] The structural unit represented by general formula (B-1) is derived from the structural unit of the cyclic olefin monomer represented by general formula (A-1), and the structural unit represented by general formula (B-2) is derived from the structural unit of the cyclic olefin monomer represented by general formula (A-2).

[0480] Transformation 4

[0481] General formula (B-1)

[0482]

[0483] In general formula (B-1), X represents -CH=CH- or -CH2CH2-. 1 ~R 4 and p are respectively related to R in general formula (A-1) 1 ~R 4 And p is the same.

[0484] 5

[0485] General formula (B-2)

[0486]

[0487] In general formula (B-2), X represents -CH=CH- or -CH2CH2-. 5 ~R 6 and p are respectively related to R in general formula (A-2) 5 ~R 6 And p is the same.

[0488] The cyclic olefin resin of the present invention can also be a commercially available product.

[0489] Examples of commercially available cyclic olefin resins include Arton G (e.g., G7810), Arton F, Arton R (e.g., R4500, R4900, and R5000), and Arton RX, manufactured by JSR (Co., Ltd., Japan).

[0490] The intrinsic viscosity [η]inh of cyclic olefin resins is preferably 0.2–5 cm⁻¹ when measured at 30°C. 3 Within the range of / g, more preferably within 0.3 to 3cm 3 Within the range of / g, and more preferably within the range of 0.4 to 1.5cm. 3 Within the range of / g.

[0491] The number average molecular weight (Mn) of the cyclic olefin resin is preferably in the range of 8,000 to 100,000, more preferably in the range of 10,000 to 80,000, and even more preferably in the range of 12,000 to 50,000.

[0492] The weight-average molecular weight (Mw) of the cyclic olefin resin is preferably in the range of 20,000 to 300,000, more preferably in the range of 30,000 to 250,000, and even more preferably in the range of 40,000 to 200,000.

[0493] The number-average molecular weight and weight-average molecular weight of cyclic olefin resins can be measured by gel permeation chromatography (GPC) using polystyrene conversion.

[0494] (Gel permeation chromatography)

[0495] Solvent: dichloromethane

[0496] Chromatographic columns: Shodex K806, K805, K803G (three of which are manufactured by Showa Denko Co., Ltd., Japan)

[0497] Column temperature: 25℃

[0498] Sample concentration: 0.1% by mass

[0499] Detector: RI Model 504 (manufactured by GL Scientific Corporation, Japan)

[0500] Pump: L6000 (manufactured by Hitachi, Ltd., Japan)

[0501] Flow rate: 1.0 mL / min

[0502] Calibration curve: A calibration curve based on 13 samples was used for standard polystyrene STK standard polystyrene (manufactured by TOSOH (Co., Ltd., Japan) with Mw = 500 to 2,800,000. It is preferred to use 13 samples at approximately equal intervals.

[0503] When the intrinsic viscosity [η]inh, number-average molecular weight, and weight-average molecular weight are within the above ranges, cyclic olefin resins exhibit good heat resistance, water resistance, drug resistance, mechanical properties, and processability as films.

[0504] The glass transition temperature Tg [°C] of cycloolefin resins is typically above 110°C, preferably in the range of 110 to 350°C, more preferably in the range of 120 to 250°C, and even more preferably in the range of 120 to 220°C.

[0505] When the glass transition temperature Tg [°C] is above 110°C, deformation under high temperature conditions is easily suppressed.

[0506] On the other hand, when the glass transition temperature Tg [°C] is below 350°C, it is easy to perform molding and processing, and it is also easy to suppress resin deterioration caused by heat during molding and processing.

[0507] The content of cyclic olefin resin is preferably 70% by mass or more, and more preferably 80% by mass or more, compared to the film.

[0508] (3.1.2) Acrylic resins

[0509] The acrylic resins of the present invention are polymers of acrylates or methacrylates, and also include copolymers with other monomers.

[0510] Therefore, the acrylic resins of the present invention also include methacrylic resins.

[0511] The resin is not particularly limited, but it is preferred to form a resin consisting of methyl methacrylate units in the range of 50 to 99% by mass and other monomer units that can be copolymerized therewith in the range of 1 to 50% by mass.

[0512] Other units constituting the acrylic resins formed by copolymerization include alkyl methacrylates with 2 to 18 carbon atoms, alkyl acrylates with 1 to 18 carbon atoms, isobornyl methacrylate, hydroxyalkyl acrylates such as 2-hydroxyethyl acrylate, acrylic acid, methacrylic acid and other α,β-unsaturated acids, acrylamide such as acrylomorpholine and N-hydroxyphenylmethylacrylamide, N-vinylpyrrolidone, maleic acid, fumaric acid, itaconic acid and other dicarboxylic acids containing unsaturated groups, styrene, α-methylstyrene and other aromatic vinyl compounds, acrylonitrile, methacrylonitrile and other α,β-unsaturated nitriles, maleic anhydride, maleimide, N-substituted maleimide, glutarimide and glutaric anhydride, etc.

[0513] Based on the above units, monomers corresponding to the above units can be listed as copolymerizable monomers other than those for glutarimide and glutaric anhydride.

[0514] That is, examples include alkyl methacrylates with 2 to 18 carbon atoms, alkyl acrylates with 1 to 18 carbon atoms, isobornyl methacrylate, 2-hydroxyethyl acrylate and other hydroxyalkyl acrylates, acrylic acid, methacrylic acid and other α,β-unsaturated acids, acrylamide, N-hydroxyphenylmethylacrylamide and other acrylamides, N-vinylpyrrolidone, maleic acid, fumaric acid, itaconic acid and other dicarboxylic acids containing unsaturated groups, styrene, α-methylstyrene and other aromatic vinyl compounds, acrylonitrile, methacrylonitrile and other α,β-unsaturated nitriles, maleic anhydride, maleimide and N-substituted maleimide and other monomers.

[0515] In addition, the glutarimide unit can be formed, for example, by reacting a primary amine (imidizing agent) with an intermediate resin having a (meth)acrylate unit to imidize it (see Japanese Patent Application Publication No. 2011-26563).

[0516] Glutaric anhydride units can be formed, for example, by heating an intermediate resin having (meth)acrylate units (see Japanese Patent No. 4961164).

[0517] From the perspective of mechanical strength, the acrylic resin of the present invention preferably contains isobornyl methacrylate, acrylmorpholine, N-hydroxyphenylmethylacrylamide, N-vinylpyrrolidone, styrene, hydroxyethyl methacrylate, maleic anhydride, maleimide, N-substituted maleimide, glutaric anhydride or glutarimide in the above-mentioned structural units.

[0518] From the perspective of controlling dimensional changes relative to variations in ambient temperature and humidity, and improving the peelability from the metal support during film production, the drying properties of organic solvents, heat resistance, and mechanical strength, the acrylic resin of the present invention preferably has a weight-average molecular weight (Mw) in the range of 50,000 to 1,000,000, more preferably in the range of 100,000 to 1,000,000, and particularly preferably in the range of 200,000 to 800,000.

[0519] When the temperature is above 50,000, the heat resistance and mechanical strength are good; when the temperature is below 1,000,000, the peelability from the metal support and the drying properties of the organic solvent are good.

[0520] The method for manufacturing the acrylic resin of the present invention is not particularly limited, and any known method such as suspension polymerization, emulsion polymerization, bulk polymerization, or solution polymerization can be used.

[0521] Here, common peroxide and azo initiators can be used as polymerization initiators, or redox initiators can also be used.

[0522] The polymerization temperature can be carried out in the range of 30 to 100°C in suspension or emulsion polymerization, and in the range of 80 to 160°C in bulk or solution polymerization.

[0523] To control the reduced viscosity of the resulting copolymer, alkyl thiols or similar substances can be used as chain transfer agents to carry out the polymerization.

[0524] From the perspective of maintaining the mechanical strength of the film, it is preferable that the glass transition temperature Tg [°C] of the acrylic resin is in the range of 80 to 120°C.

[0525] Commercially available products can also be used as the acrylic resin of this invention.

[0526] Examples include Delpet 60N, 80N, 980N, SR8200 (produced by Asahi Kasei Chemicals Co., Ltd., Japan), Dianal BR52, BR80, BR83, BR85, BR88, EMB-143, EMB-159, EMB-160, EMB-161, EMB-218, EMB-229, EMB-270, EMB-273 (produced by Mitsubishi Rayon Co., Ltd., Japan), KT75, TX400S, and IPX012 (produced by Denki Kagaku Kogyo Co., Ltd., Japan).

[0527] Two or more acrylic resins can also be used together.

[0528] The acrylic resin of the present invention preferably contains additives. As an example of additives, in order to improve the mechanical strength of the film and adjust the dimensional change rate, it preferably contains acrylic particles (rubber elastic particles) as described in International Publication No. 2010 / 001668.

[0529] Examples of commercially available products of the aforementioned multilayer acrylic granular composites include "Metabrene W-341" manufactured by Mitsubishi Rayon Corporation (Japan), "Kane Ace" manufactured by Kaneka Corporation (Japan), "Paraloid" manufactured by Kureha Corporation (Japan), "Acryloid" manufactured by Rohm and Haas Corporation (USA), "Staphyloid" manufactured by Aika Corporation, Chemisnow MR-2G, MS-300X (manufactured by Soken Chemical Co., Ltd. (Japan)), and "Parapet SA" manufactured by Kuraray Corporation. These products can be used alone or in combination of two or more.

[0530] The volume average particle size of the acrylic particles is less than 0.35 μm, preferably in the range of 0.01 to 0.35 μm, and more preferably in the range of 0.05 to 0.30 μm.

[0531] When the particle size is above a certain level, the film can be easily stretched under heating conditions; when the particle size is below a certain level, the transparency of the resulting film is not easily damaged.

[0532] From the perspective of flexibility, the flexural modulus of the film of the present invention is preferably 10.5 GPa or less (JIS K7171), more preferably 1.3 GPa or less, and even more preferably 1.2 GPa or less.

[0533] The aforementioned flexural modulus varies depending on the type and amount of acrylic resin and rubber elastic particles in the film. For example, the higher the content of rubber elastic particles, the lower the flexural modulus is usually.

[0534] Furthermore, as acrylic resins, copolymers using alkyl methacrylates and alkyl acrylates typically have a lower flexural modulus compared to homopolymers using alkyl methacrylates.

[0535] (3.1.3) Cellulose ester resins

[0536] Cellulose ester resins are also preferably used in the film rolls of the present invention.

[0537] The cellulose ester used in this invention refers to a cellulose acylated resin in which some or all of the hydrogen atoms of the 2, 3 and 6-position hydroxyl (-OH) groups in the glucose units constituting the β-1,4 bond of cellulose are replaced by acyl groups.

[0538] The cellulose esters mentioned above are not particularly limited, but esters of straight-chain or branched carboxylic acids with about 2 to 22 carbon atoms are preferred.

[0539] The carboxylic acids that make up esters can be aliphatic carboxylic acids, can be cyclic, or can be aromatic carboxylic acids.

[0540] As an example of the above, cellulose esters in which the hydrogen atoms of the hydroxyl portion are replaced by acyl groups with 2 to 22 carbon atoms, such as acetyl, propionyl, butyryl, isobutyryl, valeryl, neovaleryl, hexanoyl, octanoyl, lauroyl, and stearoyl, can be cited.

[0541] The carboxylic acid (acyl group) that makes up an ester can also have substituents.

[0542] The carboxylic acid constituting the ester is preferably a lower fatty acid with 6 or fewer carbon atoms, and more preferably a lower fatty acid with 3 or fewer carbon atoms.

[0543] It should be noted that the acyl group in cellulose ester can be a single acyl group or a combination of multiple acyl groups.

[0544] Preferred examples of cellulose esters include not only cellulose acetate such as diacetylcellulose (DAC) and triacetylcellulose (TAC), but also mixed fatty acid esters of cellulose with propionic or butyric acid groups, in addition to acetyl groups such as cellulose acetate propionate (CAP), cellulose acetate butyrate, and cellulose acetate propionate butyrate.

[0545] The aforementioned cellulose esters can be used individually or in combination.

[0546] (Type of acyl group / degree of substitution)

[0547] By adjusting the type and degree of substitution of acyl groups in cellulose esters, the humidity variation of phase difference can be controlled within the desired range, thereby improving the uniformity of film thickness.

[0548] The lower the degree of substitution of the acyl group in cellulose ester, the higher the manifestation of phase difference, thus enabling it to be made into a thin film.

[0549] On the other hand, when the substitution of the acyl group is too small, the durability may deteriorate, and therefore it is not preferred.

[0550] On the other hand, the greater the degree of substitution of the acyl group in the cellulose ester, the less obvious the phase difference becomes. Therefore, it is necessary to increase the stretching ratio during film formation. However, it is difficult to stretch uniformly with a high stretching ratio, thus increasing (worsening) the difference in film thickness.

[0551] In addition, because the lag (phase difference) in the thickness direction, i.e., the Rt humidity variation, is caused by the coordination of water molecules with the carbonyl group of cellulose, the degree of substitution of acyl groups is relatively high. That is, the more carbonyl groups there are in cellulose, the more severe the Rt humidity variation tends to be.

[0552] Cellulose esters are preferably in the range of 2.1 to 2.5 in terms of total degree of substitution.

[0553] By setting it to this range, environmental variations (especially Rt variations caused by humidity) can be suppressed, and the uniformity of film thickness can be improved.

[0554] From the perspective of improving the castability and stretchability during film formation and further improving the uniformity of film thickness, it is more preferable to be in the range of 2.2 to 2.45.

[0555] More specifically, the cellulose ester satisfies both formula (a) and (b) below. In formula (a) and (b) below, X is the degree of substitution of the acetyl group, and Y is the degree of substitution of the propionyl or butyryl group, or a mixture thereof.

[0556] Equation (a): 2.1 ≤ X + Y ≤ 2.5

[0557] Equation (b): 0 ≤ Y ≤ 1.5

[0558] Cellulose esters are more preferably cellulose acetate (Y=0) and cellulose acetate propionate (CAP) (Y; propionyl group, Y>0), and from the perspective of reducing the thickness difference of the film, cellulose acetate with Y=0 is even more preferred.

[0559] From the perspective of making the phase difference manifestation, Rt humidity variation, and film thickness difference within the desired range, the cellulose acetate used is particularly preferred to be dialdehyde cellulose (DAC) with a content of 2.1 ≤ X ≤ 2.5 (more preferably 2.15 ≤ X ≤ 2.45).

[0560] In addition, when Y > 0, the cellulose acetate propionate (CAP) used is particularly preferred with the following values: 0.95 ≤ X ≤ 2.25, 0.1 ≤ Y ≤ 1.2, and 2.15 ≤ X + Y ≤ 2.45.

[0561] By using the above-mentioned cellulose acetate or cellulose acetate propionate, film rolls with good delay, mechanical strength, and environmental adaptability can be obtained.

[0562] It should be noted that the degree of substitution of the acyl group represents the average number of acyl groups in each glucose unit, which indicates the number of hydrogen atoms at the 2, 3, and 6 positions of the hydroxyl group in a glucose unit that are replaced by acyl groups.

[0563] Therefore, the maximum degree of substitution is 3.0, which means that all hydrogen atoms of the hydroxyl groups at positions 2, 3, and 6 are replaced by acyl groups.

[0564] The acyl group can be substituted evenly at the 2, 3, and 6 positions of the glucose unit, or it can be substituted in a distributed manner.

[0565] The degree of substitution is determined using the method specified in ASTM-D817-96.

[0566] To obtain the desired optical properties, cellulose acetate with different degrees of substitution can also be mixed and used.

[0567] In the above case, the mixing ratio of different cellulose acetates is not particularly limited.

[0568] The number-average molecular weight (Mn) of cellulose esters is preferably in the range of 2 × 10⁻⁶. 4 ~3×10 5 Within the range, and therefore preferably within 2×10 4 ~1.2×10 5 Within the range, in addition, when in 4×10 4 ~8×10 4 When the temperature is within a certain range, the mechanical strength of the resulting film roll increases, and from this perspective, it is preferred.

[0569] The number-average molecular weight (Mn) of the cellulose ester was calculated by means of gel permeation chromatography (GPC) based on the measurement conditions.

[0570] The weight-average molecular weight (Mw) of cellulose esters is preferably in the range of 2 × 10⁻⁶. 4 ~1×10 6 Within the range, and therefore preferably within 2×10 4 ~1.2×10 5 Within the range, in addition, when in 4×10 4 ~8×10 4 When the temperature is within a certain range, the mechanical strength of the resulting film roll increases, and from this perspective, it is preferred.

[0571] The raw material for cellulose esters, cellulose, is not particularly limited, but examples include cotton linter, wood pulp, and kenaf.

[0572] In addition, the cellulose esters obtained from the above raw materials can be mixed and used in various arbitrary proportions.

[0573] Cellulose esters such as cellulose acetate and cellulose acetate propionate can be manufactured using known methods.

[0574] Generally, raw material cellulose, specified organic acids (acetic acid, propionic acid, etc.), acid anhydrides (acetic anhydride, propionic anhydride, etc.), and catalysts (sulfuric acid, etc.) are mixed to esterify cellulose and react until cellulose triesters are formed.

[0575] In the triester, the three hydroxyl groups of the glucose unit are replaced by acyl acids of organic acids.

[0576] When two organic acids are used simultaneously, it is possible to produce mixed ester-type cellulose esters, such as cellulose acetate propionate or cellulose acetate butyrate.

[0577] Then, cellulose ester resins with the desired degree of acyl substitution are synthesized by hydrolyzing cellulose triesters.

[0578] Subsequently, the cellulose ester resin is obtained through processes such as filtration, sedimentation, washing, dehydration, and drying. Specifically, the method described in Japanese Patent Application Publication No. 10-45804 can be used for synthesis.

[0579] (3.2) Other additives

[0580] In addition to the thermoplastic resin described above, the film roll of the present invention may also contain the following additives as other additives.

[0581] (3.2.1) Plasticizers

[0582] The film rolls of the present invention preferably contain at least one plasticizer in order to impart processability to polarizer protective films, for example.

[0583] Plasticizers are preferably used alone or in combination of two or more.

[0584] From the perspective of effectively controlling moisture permeability and compatibility with base resins such as cellulose esters, it is preferable that the plasticizer also contains at least one plasticizer selected from the group consisting of sugar esters, polyesters, and styrene compounds.

[0585] From the perspective of balancing improved resistance to damp heat and compatibility with base resins such as cellulose esters, the plasticizer preferably has a molecular weight of 15,000 or less, and more preferably 10,000 or less.

[0586] When the compound with a molecular weight of 10,000 or less is a polymer, it is preferable that the weight-average molecular weight (Mw) is 10,000 or less.

[0587] The preferred range for weight-average molecular weight (Mw) is 100 to 10,000, and more preferably 400 to 8,000.

[0588] In particular, in order to obtain the effects of the present invention, the compound having a molecular weight of 1500 or less is preferably contained in the range of 6 to 40 parts by weight relative to 100 parts by weight of the base resin, and more preferably in the range of 10 to 20 parts by weight.

[0589] By including the above-mentioned compounds within the above-mentioned range, it is possible to achieve both effective control of moisture permeability and compatibility with the base resin, and therefore it is preferred.

[0590] (glycoesters)

[0591] To prevent hydrolysis, the film roll of the present invention may also contain sugar ester compounds.

[0592] Specifically, as a sugar ester compound, a sugar ester having at least one pyranose structure or a furanose structure with one or more but less than twelve OH groups can be used, and all or part of such structure is esterified.

[0593] (Polyester)

[0594] The film roll of the present invention may also contain polyester.

[0595] Polyesters are not particularly limited, but for example, dicarboxylic acids, or polymers with hydroxyl-terminated ends (polyester polyols) that can be obtained by the condensation reaction of the above-mentioned esterification derivatives with diols, or polymers in which the hydroxyl-terminated ends of the polyester polyols are sealed by monocarboxylic acids (end-sealed polyesters) can be used.

[0596] It should be noted that the ester derivatives mentioned here refer to esterified dicarboxylic acids, dicarboxylic acid chlorides, and dicarboxylic acid anhydrides.

[0597] (Styrene compounds)

[0598] In order to improve the water resistance of the film roll of the present invention, in addition to or replacing the above-mentioned sugar esters and polyesters, styrene compounds may also be used.

[0599] Styrene compounds can be homopolymers of styrene monomers or copolymers of styrene monomers with other comonomers.

[0600] In order to give the molecular structure a certain volume, the proportion of structural units derived from styrene monomers in styrene compounds is preferably in the range of 30 to 100 mol%, and more preferably in the range of 50 to 100 mol%.

[0601] Examples of styrene monomers include: styrene; alkyl-substituted styrene such as α-methylstyrene, β-methylstyrene, and p-methylstyrene; halogen-substituted styrene such as 4-chlorostyrene and 4-bromostyrene; hydroxystyrene such as p-hydroxystyrene, α-methyl-p-hydroxystyrene, 2-methyl-4-hydroxystyrene, and 3,4-dihydroxystyrene; vinylbenzyl alcohol; alkoxy-substituted styrene such as p-methoxystyrene, p-tert-butoxystyrene, and m-tert-butoxystyrene; vinylbenzoic acid such as 3-vinylbenzoic acid and 4-vinylbenzoic acid; 4-vinylbenzyl acetate; 4-acetoxystyrene; amides such as 2-butylamidestyrene, 4-methylamidestyrene, and p-sulfonamidestyrene; aminostyrene such as 3-aminostyrene, 4-aminostyrene, 2-isopropenylaniline, and vinylbenzyldimethylamine; nitrostyrene such as 3-nitrostyrene and 4-nitrostyrene; cyanostene such as 3-cyanostene and 4-cyanostene; vinylphenylacetonitrile; arylstyrene such as phenylstyrene; and indene.

[0602] Styrene monomers can be one type or a combination of two or more types.

[0603] (3.2.2) Any component

[0604] The film roll of the present invention may contain antioxidants, colorants, ultraviolet absorbers, matting agents, acrylic particles, hydrogen-bonded solvents, ionic surfactants, and other arbitrary components.

[0605] The above-mentioned components can be added in the range of 0.01 to 20 parts by weight relative to 100 parts by weight of the base resin.

[0606] (Antioxidants)

[0607] The film rolls of the present invention can use commonly known antioxidants as antioxidants.

[0608] In particular, lactones, sulfur compounds, phenols, double bonds, hindered amines, and phosphorus compounds can be preferred.

[0609] The antioxidants and the like are added in the range of 0.05% to 20% by mass, preferably in the range of 0.1% to 1% by mass, relative to the main raw material of the film, namely the resin.

[0610] The aforementioned antioxidants, when used in combination with different types of compounds, can achieve a synergistic effect than when using only one compound.

[0611] For example, it is preferable to use lactones, phosphorus compounds, phenols, and double bond compounds.

[0612] (Coloring agent)

[0613] The film roll of the present invention preferably contains a colorant for color adjustment, to the extent that it does not impair the effects of the present invention.

[0614] Colorant refers to dye or pigment. In this invention, it refers to a colorant that has the effect of making the hue of the liquid crystal screen blue or adjusting the yellow index and reducing haze.

[0615] Various dyes and pigments can be used as coloring agents, with anthraquinone dyes, azo dyes, and phthalocyanine pigments being effective.

[0616] (UV absorber)

[0617] Since the thin film roll of the present invention can also be used on the viewing side or the backlight side of a polarizer, it can also contain an ultraviolet absorber for the purpose of imparting ultraviolet absorption function.

[0618] As a UV absorber, there is no particular limitation, but examples include UV absorbers such as benzotriazoles, 2-hydroxybenzophenones, or phenyl salicylate.

[0619] Examples of triazoles include 2-(5-methyl-2-hydroxyphenyl)benzotriazole, 2-[2-hydroxy-3,5-bis(α,α-dimethylbenzyl)phenyl]-2H-benzotriazole, 2-(3,5-di-tert-butyl-2-hydroxyphenyl)benzotriazole, benzophenones include 2-hydroxy-4-methoxybenzophenone, 2-hydroxy-4-octoxybenzophenone, and 2,2′-dihydroxy-4-methoxybenzophenone.

[0620] The aforementioned ultraviolet absorbers can be used alone or in combination of two or more.

[0621] The amount of ultraviolet absorber used varies depending on the type of ultraviolet absorber and the conditions of use. Generally, it can be added in the range of 0.05% to 10% by mass, preferably in the range of 0.1% to 5% by mass, relative to the base resin.

[0622] (particle)

[0623] The film roll of the present invention preferably contains microparticles that impart slip properties to the film roll.

[0624] In particular, from the perspective of improving the slipperiness of the film surface of the present invention, improving the slipperiness during winding, and preventing scratches and adhesion, adding microparticles is effective.

[0625] As microparticles, they can be any microparticles, whether inorganic or organic, as long as they do not impair the transparency of the resulting film roll and have heat resistance when melted, but inorganic microparticles are preferred.

[0626] The aforementioned particles can be used individually or in combination.

[0627] By combining particles of different sizes or shapes (such as needle-like and spherical), it is also possible to achieve a high degree of balance between transparency and smoothness.

[0628] Since the refractive index of the compounds constituting the above-mentioned particles is close to that of the cycloolefin resins, acrylic resins or cellulose ester resins, silica with good transparency (haze) is particularly preferred.

[0629] As specific examples of silica, commercially available products with trade names such as Aerosil 200V, Aerosil R972V, Aerosil R972, R974, R812, 200, 300, R202, OX50, TT600, NAX50 (the above are produced by Aerosil Ltd. of Japan), Seahoster KEP-10, Seahoster KEP-30, Seahoster KEP-50 (the above are produced by Nippon Shokubai Ltd. of Japan), Sylophobic 100 (produced by Fuji Silysia Ltd. of Japan), Nipsil E220A (produced by Silica Industries Ltd. of Japan), and Admafine SO (produced by Admatechs Ltd. of Japan) are preferred.

[0630] As for the shape of the particles, there are no particular restrictions on using irregular, needle-shaped, flat, spherical, etc. However, spherical particles are preferred, especially since they can make the resulting film rolls have good transparency.

[0631] When the size of the particles is close to the wavelength of visible light, light scattering occurs and transparency deteriorates. Therefore, it is preferable that the particle size is smaller than the wavelength of visible light, and even more preferably less than half the wavelength of visible light.

[0632] When the particle size is too small, it may not improve the sliding properties, so the particle size is particularly preferred in the range of 80 to 180 nm.

[0633] It should be noted that particle size refers to the size of the aggregate when the particles are primary particles.

[0634] In addition, when the particles are not spherical, the particle size refers to the diameter of a circle whose projected area is equivalent to that of the particle.

[0635] The microparticles are preferably added in the range of 0.05 to 10% by mass, and more preferably in the range of 0.1 to 5% by mass, relative to the base resin.

[0636] 4. Polarizing filter

[0637] A portion of the thin film in the thin film roll of the present invention can be suitably used by being configured on a polarizer.

[0638] Polarizers are typically composed of a polarizer film (also known as a "polarizing film" or "polarizer membrane") and a transparent resin film laminated on both sides thereon. A portion of the film roll of the present invention may be disposed on the polarizer as such a resin film.

[0639] Examples of polarizers include polarizers having a structure that uses a polarizer layer with a polarizer film, a polarizer protective film using a resin film, and an adhesive layer disposed therebetween.

[0640] (4.1) Polarizer layer

[0641] The aforementioned polarizer layer is a layer formed of at least a polarizer thin film.

[0642] Here, "polarizer" refers to a component that allows light to pass through a polarization plane that is only in a certain direction.

[0643] Examples of polarizing films include polyvinyl alcohol-based polarizing films and cellulose ester-based polarizing films. However, polyvinyl alcohol-based resins are preferred over cellulose ester-based resins because they offer better transparency, optical properties, and durability.

[0644] Polyvinyl alcohol polarizing films include polarizing films dyed with iodine on polyvinyl alcohol films and polarizing films dyed with diachromic dyes.

[0645] Polyvinyl alcohol polarizing film can be a film made by uniaxially stretching a polyvinyl alcohol film and then dyeing it with iodine or a bispherical dye (preferably a film that has undergone a durability treatment with a boron compound), or a film made by dyeing a polyvinyl alcohol film with iodine or a bispherical dye and then uniaxially stretching it (preferably a film that has undergone a durability treatment with a boron compound).

[0646] The absorption axis of the polarizer layer is usually parallel to the direction of maximum stretching.

[0647] For example, ethylene-modified polyvinyl alcohol can be used, as described in Japanese Patent Application Publication No. 2003-248123 and Japanese Patent Application Publication No. 2003-342322, with an ethylene unit content of 1 to 4 mol%, a degree of polymerization of 2000 to 4000, and a degree of saponification of 99.0 to 99.99 mol%.

[0648] The thickness of the polarizer layer is preferably 5 to 30 μm, and more preferably 5 to 20 μm in order to make the polarizer thinner.

[0649] (4.2) Polarizing protective film

[0650] A portion of the thin film of the present invention can be configured on at least one side of the polarizer layer (at least the side opposite the liquid crystal cell), and can be used as a polarizer protective film or a phase difference film.

[0651] The surface of the laminated polarizer layer of the polarizer protective film can also undergo the activation treatment described later.

[0652] In the case where a portion of the thin film of the present invention is configured as a polarizer protective film on only one side of the polarizer layer, other optical films such as a phase difference film can be configured on the other side of the polarizer layer.

[0653] Examples of other optical films include commercially available cellulose ester films (e.g., Konica Minolta Tack KC8UX, KC5UX, KC4UX, KC8UCR3, KC4SR, KC4BR, KC4CR, KC4DR, KC4FR, KC4KR, KC8UY, KC6UY, KC4UY, KC4UE, KC8UE, KC8UY-HA, KC2UA, KC4UA, KC6UA, KC8UA, KC2UAH, KC4UAH, KC6UAH, KC2UAH, KC6UAH, all manufactured by Konica Minolta (Japan) Co., Ltd.); Fuji Tac T40UZ, Fuji Tac T60UZ, Fuji Tac T80UZ, Fuji Tac TD80UL, Fuji Tac TD60UL, Fuji Tac TD40UL, Fuji Tac R02, Fuji...). TacR06, etc. (These are products of Fuji Film (Co., Ltd., Japan).

[0654] The thickness of other optical thin films can be, for example, 5 to 100 μm, preferably 40 to 80 μm.

[0655] (4.3) Adhesive layer

[0656] The adhesive layer is a layer disposed between a portion of the film (or other optical film) of the film roll of the present invention and the polarizer layer, which is used to dry a water-based adhesive or a UV-curable adhesive.

[0657] The thickness of the adhesive layer can be, for example, 0.01 to 10 μm, preferably about 0.03 to 5 μm.

[0658] (Water-based adhesive)

[0659] Examples of water-based adhesives include: vinyl, gelatin, vinyl latex, polyurethane, isocyanate, polyester, epoxy, etc.

[0660] When using a polyvinyl alcohol polarizing film in the polarizer layer, from the perspective of easily obtaining adhesion, an aqueous adhesive containing ethylene resin is preferred, and an aqueous adhesive containing polyvinyl alcohol resin (such as a fully saponified polyvinyl alcohol aqueous solution) is more preferred.

[0661] Water-based adhesives containing polyvinyl alcohol resins may also contain water-soluble crosslinking agents such as boric acid or borax, glutaraldehyde or melamine, and oxalic acid.

[0662] (UV-curing adhesive)

[0663] UV-curable adhesives can be photoradical polymers or photocationic polymers.

[0664] Among them, photocationically polymerizable compositions are preferred.

[0665] Photocationically polymerizable compositions include epoxy compounds and photocationically polymerizable initiators.

[0666] Epoxy compounds are compounds that have one or more, preferably two or more, epoxy groups in their molecules.

[0667] Examples of epoxy compounds include: hydrogenated epoxy compounds (glycidyl ethers of polyols having an alicyclic ring) obtained by reacting epichlorohydrin with an alicyclic polyol; aliphatic epoxy compounds such as polyglycidyl ethers of aliphatic polyols or their olefinic adducts; and alicyclic epoxy compounds having one or more epoxy groups bonded to an alicyclic ring within the molecule.

[0668] Epoxy compounds can be used alone or in combination.

[0669] Photocationic polymerization initiators can be, for example, aromatic diazonium salts, aromatic iodonium salts, aromatic thiodonium salts, iron-aromatic complexes, etc.

[0670] Depending on the requirements, the photocationic polymerization initiator may also contain cationic polymerization promoters such as oxetane and polyols, photosensitizers, solvents, and other additives.

[0671] (4.4) Manufacturing method of polarizer

[0672] The method for manufacturing a polarizer of the present invention comprises: 1) a step of performing an activation treatment on the surface of a polarizer protective film; 2) a step of laminating a polarizer layer (polarizing film) on the activated surface of the polarizer protective film using an aqueous adhesive or an ultraviolet curing adhesive; and 3) a step of drying the resulting laminate.

[0673] Regarding the process in 1),

[0674] The surface of the polarizer protective film (the surface that is bonded to the polarizer layer) is activated.

[0675] Therefore, adhesion to the polarizer layer is easily obtained.

[0676] Specifically, by activating the polarizer protective film, the siloxane or ether bonds, tertiary carbon atoms, etc. of the specified grafted polymer side chains are hydrophilized, which improves the affinity with water-based adhesives or makes them easier to interact with each other, thereby making the polarizer protective film easy to bond to the polarizer layer.

[0677] Examples of activation treatments include: corona treatment, plasma treatment, and saponification treatment, preferably corona treatment and plasma treatment, and more preferably corona treatment.

[0678] The activation treatment conditions are sufficient to fully activate the siloxane bonds, ether bonds, tertiary carbon atoms, etc. contained in the side chains of the specified graft polymer.

[0679] When the activation treatment is corona treatment, the irradiation dose is preferably 100–1000 [W·min / m²]. 2 More preferably, the range is 150–900 [W·min / m³]. 2 Within the range of ].

[0680] Regarding process 2):

[0681] Next, the polarizer layer is laminated onto the activated surface of the polarizer protective film using an aqueous adhesive or an ultraviolet-curing adhesive.

[0682] Regarding process 3):

[0683] Next, the resulting laminate is dried to obtain a polarizing film.

[0684] Drying can be achieved through heating.

[0685] The drying temperature can be any temperature that allows the water-based adhesive or the UV-curing adhesive to dry completely, for example, within the range of 60 to 100°C.

[0686] 5. Display device

[0687] A portion of the thin film of the present invention can be suitably used by being disposed in a display device.

[0688] Examples of display devices include liquid crystal displays (LCDs), organic EL displays, and various other image display devices.

[0689] Hereinafter, examples of the use of the thin film as part of the thin film roll of the present invention will be described, specifically in the case where it is disposed as a polarizer protective film in a polarizer and a liquid crystal display device.

[0690] (5.1) Liquid crystal display device

[0691] As a display device of the present invention, specifically, for example, a liquid crystal display device including a liquid crystal cell and a pair of polarizers holding the liquid crystal cell can be cited.

[0692] Figure 18 This is a schematic diagram illustrating an example of the structure of the liquid crystal display device of the present invention.

[0693] like Figure 18 As shown, the liquid crystal display device (200) includes: a liquid crystal cell (220), a first polarizer (210) and a second polarizer (230) that hold the liquid crystal cell, and a backlight (240).

[0694] The display mode of the LCD cell (220) can be various display modes such as STN, TN, OCB, HAN, VA (MVA, PVA), IPS, etc. In order to obtain high contrast, the VA (MVA, PVA) mode is preferred.

[0695] The first polarizer (210) includes: a first polarizer (212), a polarizer protective film (211) disposed on the side of the first polarizer (212) opposite to the liquid crystal cell, and a polarizer protective film (213) disposed on the side of the first polarizer (212) on the side of the liquid crystal cell.

[0696] The second polarizer (230) includes: a second polarizer (232), a polarizer protective film (231) disposed on the liquid crystal cell side of the second polarizer (232), and a polarizer protective film (233) disposed on the side of the second polarizer (232) opposite to the liquid crystal cell. One of the polarizer protective films (213) and (231) may be omitted as needed.

[0697] Moreover, at least one of the polarizer protective film (211) and (233) can be the resin film of the present invention.

[0698] (5.2) Other uses

[0699] A portion of the thin film of the present invention can be used not only as a polarizer protective film for liquid crystal display devices, but also preferably as a protective film for image display devices such as image display devices with touch panels, organic EL displays, or plasma displays.

[0700] It should be noted that the embodiments applicable to this invention are not limited to the above embodiments, and appropriate modifications can be made without departing from the spirit of this invention.

[0701] [Example]

[0702] The present invention will now be illustrated with specific examples, but the invention is not limited thereto. It should be noted that the expressions “parts” or “%” are used in the examples, and unless otherwise specified, they refer to “parts by mass” or “% by mass”.

[0703] [A. Fabrication of a thin film roll]

[0704] [Production of A.1 Thin Film Roll No.1]

[0705] Thin films are formed using solution casting.

[0706] (Dopant preparation process [S1])

[0707] <Synthesis of Cyclic Polyolefin Polymer [P-1]>

[0708] 100 parts by weight of purified toluene and 100 parts by weight of norborneol methyl carboxylate were added to a stirring device.

[0709] Then, 25 mol% (based on monomer mass) of ethyl hexanoate-Ni dissolved in toluene, 0.225 mol% (based on monomer mass) of tri(pentafluorophenyl)boron, and 0.25 mol% (based on monomer mass) of triethylaluminum dissolved in toluene were added to the stirring apparatus.

[0710] Stir at room temperature and allow to react for 18 hours.

[0711] After the reaction is complete, the reaction mixture is added to excess ethanol to form a polymer precipitate.

[0712] The polymer obtained by purifying the precipitate was dried under vacuum at 65°C for 24 hours to synthesize the cyclic polyolefin polymer [P-1].

[0713] <Preparation of Cyclic Polyolefin Solution (Dopant [D-1])>

[0714] The following composition [1] was added to a mixing tank and stirred to dissolve the components. The solution was 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 cyclic polyolefin solution (dopant [D-1]).

[0715] Composition [1]

[0716] • Cyclic polyolefin polymer [P-1] 25 parts by weight

[0717] ·65 parts by weight of dichloromethane

[0718] 10 parts by weight of ethanol

[0719] <Preparation of particulate dispersion [1]>

[0720] Then the following composition [2] is added to a disperser to prepare a particulate dispersion [1] as an additive.

[0721] Composition [2]

[0722] • Microparticles (Aerosil R812: manufactured by Aerosil Corporation of Japan, primary average particle size: 7nm, apparent specific gravity: 50g / L) 4 parts by weight

[0723] 76 parts by weight of dichloromethane

[0724] 20 parts by weight of ethanol

[0725] <Preparation of dopant for film formation [1]>

[0726] The above 100 parts by mass of cyclic polyolefin solution (dopant [D-1]) and 0.75 parts by mass of particulate dispersion [1] were mixed to prepare film-forming dopant [1] (resin composition cyclic olefin resin: COP).

[0727] (Cast casting process [S2])

[0728] The film-forming dopant [1] (resin composition cyclic olefin resin: COP) prepared in the dopant preparation step [S1] is fed into the casting mold through a conduit by a pressurized fixed gear pump. On the film-forming production line, the dopant is cast from the casting mold to the casting position on a support formed by an infinitely conveying rotating stainless steel annular belt with a width of 1800 mm. The support is heated until the dopant becomes self-supporting and the solvent evaporates until the cast film can be peeled off from the support by the peeling roller. The film is then dried to form a cast film.

[0729] (Stripping process [S3])

[0730] After the cast film is formed in the casting process (S2), the cast film is peeled off from the support body by the peeling roller while still maintaining its self-supporting properties.

[0731] (Shrinkage process [S4])

[0732] The film is subjected to high-temperature treatment without maintaining its thickness in the width direction to increase its density, thereby causing the film to shrink in the width direction at a shrinkage rate of 7%.

[0733] (First drying process [S5])

[0734] Then, the film is heated on the support to evaporate the solvent.

[0735] The residual solvent content of the film was measured using the following method, and the result was less than 5% by mass.

[0736] <Measurement of Residual Solvent Content>

[0737] The residual solvent content was analyzed by gas chromatography as described below.

[0738] That is, collect a thin film at any location, and in order to prevent the solvent remaining in the film from evaporating, ensure that it is quickly filled into a vial and the cap is screwed on.

[0739] Then, the needle was inserted into the vial, and quality analysis was performed using a gas chromatograph (manufactured by Agilent Technologies Ltd., Japan).

[0740] It should be noted that the amount of residual solvent is defined by the following formula.

[0741] Residual solvent content [mass %] = {(M - N) / N} × 100

[0742] It should be noted that M in the above formula is the mass [g] of the sample collected at any time point during or after the manufacturing of the cast film or thin film, and N in the above formula is the mass [g] of the sample after heating at 115°C for one hour.

[0743] (First stretching process [S6])

[0744] Then, the film is transported in the stretching device of the tenter frame for lateral stretching.

[0745] (First cutting process [S7])

[0746] Cut the two ends of the stretched film in the width direction.

[0747] (Second stretching process [S8])

[0748] Similar to the first stretching process, the film is stretched by the tenter frame stretching device.

[0749] The residual solvent content of the film was measured using the above method, and the result was 1-5% by mass.

[0750] (Second cutting process [S9])

[0751] Similar to the first cutting process, the two ends of the stretched film in the width direction are cut.

[0752] (Second drying process [S10])

[0753] Similar to the first drying process, the film is heated on the support to evaporate the solvent.

[0754] The residual solvent content of the film was measured using the above method, and the result was 0.1–2% by mass.

[0755] (Third cutting process [S11])

[0756] Similar to the first and second cutting processes, the two ends of the stretched film in the width direction are cut.

[0757] (Winding process [S12])

[0758] The film is wound at a winding speed of 60 m / min (the speed of the film transport production line), a film roll width of 2000 mm, and a winding length of 10000 m.

[0759] The thickness of the film during winding was measured and found to be 40 μm.

[0760] In addition, using a winding device and TR (contact rollers), the contact pressure at the periphery of the core during winding is adjusted to 16.0 N / m and the tension to 40 N / m, the contact pressure at the center of the roll is adjusted to 16.0 N / m and the tension to 40 N / m, and the contact pressure at the outer periphery of the roll is adjusted to 15.2 N / m and the tension to 40 N / m, with a taper of 70% and a corner angle of 25%.

[0761] The thickness of the thin film was measured at 1612 locations using an online delay / film thickness measurement device RE-200L2T-Rth+ (manufactured by Otsuka Electronics Co., Ltd., Japan). The height difference between the highest and lowest parts of the uneven structure formed on the film surface was calculated as its average value.

[0762] At this time, the lateral movement speed is 100 mm / sec.

[0763] The above process is used to produce film roll No. 1.

[0764] [Preparation of A.2 film rolls No.2-13]

[0765] Except for the changes shown in Table I regarding the type of dopant (resin composition) used for film formation in the dopant preparation process (S1), the winding length [m], winding speed [m / min], film thickness [μm], contact pressure [N / m] and tension [N / m] at the periphery of the core during winding, contact pressure [N / m] and tension [N / m] at the center of the roll, and contact pressure [N / m] and tension [N / m] at the outer periphery of the roll, film rolls No. 2 to 13 were manufactured in the same manner as film roll No. 1.

[0766] [Table 1]

[0767]

[0768] [Calculation of the void layer thickness at the periphery, center, and outer periphery of roll B]

[0769] After storing each film roll at 40℃ / 80%RH for one week, the void layer thickness of the core periphery, the center of the roll, and the outer periphery of the roll is calculated using the method described (an example of a method for calculating void layer thickness).

[0770] The following describes the specific method for calculating the thickness of the void layer at the periphery of the core using film roll No.1.

[0771] After storing the film roll No. 1 for one week, at the position where the width direction of the roll diameter is 20% (P) 20 Using [a specific object] as the center, take a picture of the side profile to obtain the image data. Perform edge enhancement processing on the obtained image data to obtain [the desired image]. Figure 5 The image shown is a processing image used to calculate the thickness of the void layer.

[0772] Then, the center of the processed image (P) 20 Starting from the point on the outer side of the roll perpendicular to the film surface, and ending at the point on the 100th layer, measure the length in the radial direction, and use the following formula (A) to calculate the thickness X [μm] of the void layer around the core.

[0773] Equation (A) Thickness of the void layer X [μm] = [Radial length [μm] - (Average thickness of each thin film layer measured by a film thickness gauge [μm]) × (Number of layers)] ÷ (Number of layers)

[0774] Substituting the measured value, the thickness of the void layer of film roll No.1 is X [μm] = [4020μm - 40.00μm × 100] ÷ 100 = 0.20μm.

[0775] Regarding the thickness of the void layer in the center of the roll, except for the position where the roll diameter is 50% on the side in the width direction (P) 50 Take a picture of the side profile as the center, and then process the image by taking the center (P). 50 Apart from the starting point, all other values ​​are calculated using the same thickness as the void layer around the core.

[0776] Regarding the thickness of the void layer at the outer periphery of the roll, except for the position where the roll diameter on the side surface in the width direction is 80% (P) 80 Take a picture of the side profile as the center, and then process the image by taking the center (P). 80 Apart from the starting point, all other values ​​are calculated using the same thickness as the void layer around the core.

[0777] [C Assessment]

[0778] [C.1 Evaluation of the quantity based on winding deviation]

[0779] (Assessment Methodology)

[0780] After being stored for one week, each film roll was placed in a transport environment recorder "Tough Logger TR-1000" (manufactured by IMV Ltd.), and a vibration test was conducted with a speed of 5.8 m / s applied to the width direction of the film roll. 2 The film roll was subjected to acceleration for 30 minutes, and the left and right deviations of the end face in the width direction were measured. The evaluation was based on the following evaluation criteria. The results are shown in Table I.

[0781] The following is an explanation of the "left and right deviation" mentioned above.

[0782] Figure 19 It is a conceptual diagram representing the left and right deviation of the end face of the film roll in the width direction when viewed from a direction orthogonal to the width direction of the film roll.

[0783] Before the vibration test, the end face of the film roll (30) in the width direction had no deviation in the left and right directions. This end face was taken as the shortest end face (S) among the end faces in the width direction of the film roll. S ).

[0784] In addition, such as Figure 19 As shown, by conducting vibration tests on the film roll, various deviations were generated at the end faces of the film roll. The end face with the largest deviation was taken as the longest end face in the width direction of the film roll (S). L ).

[0785] Then, take the shortest end face (S) among the end faces in the width direction of the above-mentioned film roll. S The longest end face (S) in the width direction of the film roll. LThe deviation length in the width direction of the film roll is referred to as the "left and right deviation of the end face in the width direction of the film roll".

[0786] (Evaluation Benchmark)

[0787] ○: Deviation is less than 2mm.

[0788] △: Deviation is greater than 2mm but less than 10mm.

[0789] ×: Deviation is 10mm or more.

[0790] [C.2 Assessment based on the degree of adhesion failure during long-term storage]

[0791] (Assessment Methodology)

[0792] The aforementioned film rolls were stored in a warehouse at room temperature for one month. Afterward, a portion of the film from each roll was unrolled, and the condition of the film and the film roll was visually observed. An evaluation was conducted based on the following evaluation criteria. The results are shown in Table I.

[0793] (Evaluation Benchmark)

[0794] ◎: No adhesion between films was observed, and there were no wrinkles or deformations.

[0795] 〇: There is slight adhesion between the films, and a few wrinkles can be observed on the surface of the film roll. No deformation was found.

[0796] △: There is adhesion between the films, wrinkles can be observed on the surface of the film roll, and some deformation is found, but there are no practical problems.

[0797] ×: There is severe adhesion between the films, severe wrinkles can be observed from the surface to the interior of the film roll, severe deformation is found on the surface of the film roll, and deformation is found to extend into the interior.

[0798] [D Summary]

[0799] Based on the conditions and evaluation results shown in Table I, it can be seen that, compared with the comparative example, the embodiments of the present invention did not exhibit winding deviation during vibration testing and did not show adhesion failure during long-term storage.

Claims

1. A film roll without an embossing section, characterized in that, When the thickness of the gap layer between adjacent films at the periphery of the core, measured on the side of the film roll in the width direction, is defined as X, and the thickness of the gap layer between adjacent films at the periphery of the roll is defined as Y, and the units of X and Y are set to μm, X and Y satisfy the following relationships (1) to (3). Formula (1) X<Y; Equation (2) 0.15 < X < 0.40; Formula (3) 1<(Y / X)≤3.

2. A polarizer, characterized in that, A portion of the film is configured with the film roll as described in claim 1.

3. A display device, characterized in that, A portion of the film is configured with the film roll as described in claim 1.

4. A method for manufacturing a film roll, comprising manufacturing a film roll without an embossing section, characterized in that, When the thickness of the gap layer between adjacent films at the periphery of the core, measured on the side of the film roll in the width direction, is defined as X, and the thickness of the gap layer between adjacent films at the periphery of the roll is defined as Y, and the units of X and Y are set to μm, X and Y are adjusted to satisfy the relationship of the following equations (1) to (3). Formula (1) X<Y; Equation (2) 0.15 < X < 0.40; Formula (3) 1<(Y / X)≤3.

5. The method for manufacturing a thin film roll as described in claim 4, characterized in that, The film contact pressure at the periphery of the core is adjusted to a range of 6 to 55 N / m, the film contact pressure at the center of the roll is adjusted to a range of 4 to 40 N / m, and the film contact pressure at the outer periphery of the roll is adjusted to a range of 3 to 30 N / m.

Images