JP2013046966A - Method of manufacturing optical film - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method of manufacturing an optical film capable of reducing failures such as loosening of winding, winding shift, horseback failure generated during winding and failures such as transfer and adhesion generated during storage, when manufacturing a wide, thin-film, and long optical film by high-speed winding.SOLUTION: In this method of manufacturing the optical film for winding the optical film around a winding shaft while applying knurling to both ends to turn it into a roll body, the winding of the optical film to the winding shaft is characterized in that the winding length of the roll body and the number of revolutions of the shaft are measured, and a gap of the optical film wound around the winding shaft is controlled on the basis of the measured information while changing the height of the knurling.

Description

  The present invention relates to a method for producing an optical film. More specifically, the present invention relates to a method for producing an optical film that prevents the occurrence of winding deviation, sticking, wrinkles, and the like when the produced long (several thousands m) optical film is used as a take-up roll body on a take-up shaft.

  As a method for producing an optical film, a solution casting method and a melt extrusion method are known. When a long optical film manufactured by such a manufacturing method is wound on a winding shaft, wrinkles are generated, the wound roll body is loosened, misaligned, or when stored for a long time, It is known that there is a problem that a failure called a core transfer is likely to occur in the cook and winding shaft portions.

  In addition, it is known that winding up entrained air in accordance with increasing winding speed in order to increase production efficiency causes winding looseness failure, winding misalignment during long-term storage, and dents due to deflection due to its own weight. . These failures occur remarkably as the winding speed increases and the optical film to be produced becomes wider, thinner, and longer.

  In order to prevent the occurrence of these failures, in general, uneven portions (knurling portions) are provided at both ends of the optical film, the tension at the time of winding is changed according to the winding diameter of the roll body, A method has been adopted in which the surface of the roll body is pressed to prevent entrainment of entrained air.

  In recent years, various display devices such as a liquid crystal television, a plasma display (PDP), and an organic EL display in which an optical film is used have been developed, and it is required to be thin and lightweight. Along with this, the quality of optical films used in these display devices has become stricter. From the viewpoint of reducing the cost of liquid crystal display components, optical films are being made wider, thinner, and longer. When there is no failure at high speed and the winding core is a winding roll body, it is difficult to maintain the quality of the roll body for a long period of time.

  In optical films used for display devices, failure such as crock, core transfer, wrinkles, etc. becomes a fatal defect, so failure occurs when winding up long optical films and long-term storage. Prevented manufacturing methods have been investigated.

  For example, with a lion roll having a pressing mechanism, the pressing force on the polymer film is continuously changed in the range of 60 N to 30 N in accordance with the change of the winding diameter with respect to the winding shaft, and 30 m / min or more and 200 m / min or less. A method of winding at a winding speed of 2 is known (see, for example, Patent Document 1).

  In order to suppress the occurrence of depressions and black belts that occur when the film roll is stored, the thickness difference in the width direction of the plastic film is set to 0 to 5 μm, and the thickness is given to the side edges of 3 to 15 μm. A winding method is known in which the thickness of the air layer between one film is 2 μm to 6.5 μm (see, for example, Patent Document 2).

  By the method described in the above-mentioned patent document, it is possible to suppress a failure that occurs when the optical film is wound around a winding shaft to a certain extent to form a roll body. However, in the case of being used as an optical film of a recent high-definition liquid crystal display device, a slight failure may cause a problem of image unevenness.

  In particular, in the present situation where widening, thinning, lengthening, and high-speed winding are required, the winding method as described in the above-mentioned patent document is used as an optical film of a recent high-definition liquid crystal display device. It was difficult to meet the requirements and further improvements were required.

  Under these circumstances, there is a demand for a method for producing an optical film that is free from failures during winding and storage in the production of optical films by wide, thin, long, and high-speed winding, and as a result, liquid crystal displays. Development of an optical film that can suppress display unevenness of the device, a polarizing plate using the same, and a liquid crystal display device has been desired.

  However, the cause of failure occurrence due to wide, thin film, long, and high-speed winding has not been scrutinized, and no method has been found to reduce failures that occur during winding and storage, and studies are desired. It was.

Japanese Patent No. 3955518 JP 2002-255409 A

  The present invention has been made in view of the above circumstances, and its object is to produce loose, wound, and horseback that occurs during winding when a wide, thin, and long optical film is manufactured by high-speed winding. An object of the present invention is to provide a method for producing an optical film in which failure such as transfer and cooking occurring at the time of failure and storage is reduced.

In the production of an optical film by the solution casting method or melt extrusion method, the present inventors loosen winding, misalignment, and storage that occur when winding a wide, thin, or long optical film on a winding shaft at high speed. As a result of investigating why the transfer, cooking, etc. that sometimes occur are likely to occur, the following was found.
1. Near the winding shaft (at the beginning of the winding), sticking to the winding shaft, transfer of the shape of the surface of the winding shaft, and clogging between the optical films occur, and winding deviation occurs outside the winding.
2. As the thickness of the optical film wound up in one roll increases from 5000 m to 8000 m as the film is thinned, the roll body increases in mass, so that the roll body is curved during long-term storage, and the thickness is reduced to 50 μm or less. As the elasticity decreases, the gap between the optical films partially disappears and a crack occurs. Further, a failure (hereinafter referred to as a horse back failure) occurs in which a dent is formed on the upper part of the film roll. This failure occurs more markedly as the production speed increases, entrained air enters, and the film thickness decreases.
3. Since the height of the knurling provided at both ends is constant, the amount of entrained air is reduced by increasing the surface pressure due to the tension during winding on the take-up shaft, and the knurling is crushed, resulting in cracking. To do. Outside the winding, the winding diameter is increased to reduce the tension at the time of winding, and the surface pressure is lowered, so that the knurling is not crushed, but the amount of entrained air is increased, so that winding deviation occurs. In particular, it becomes remarkable when the width of the optical film exceeds 2 m. It is difficult to increase the height so that the effect of knurling can be obtained even if it is crushed because the height of the knurling is cracked or perforated as the film is made thinner.
4). As the thickness of the optical film to be manufactured varies, the increase in winding diameter and the height of the knurling change relatively, so the surface pressure associated with the tension during winding varies, and the amount of entrained air varies. However, the distance between the optical films becomes unstable. As a result, failures such as loose winding, winding deviation, and tackiness of the roll body occur.

  Therefore, in order to effectively prevent failures such as loosening, winding deviation, and transfer, cooking, etc. that occur during storage when a wide, thin film, or long optical film is manufactured by high-speed winding. In addition to increasing the tension corresponding to the winding diameter and making the amount of entrained air constant, further winding without changing the height of the knurling, while changing the winding diameter according to the winding diameter, optical As a result of studying that it is effective to produce a film, the present invention has been achieved.

  The above object of the present invention has been achieved by the following constitution.

1. In the method for producing an optical film having an optical film as a take-up roll body while giving a knurling to both ends,
Winding of the optical film to the winding shaft measures the winding length and shaft rotation speed of the roll body,
A method for producing an optical film, comprising: controlling a gap between the optical films wound on the winding shaft while changing a height of the knurling based on the measured information.

  2. 2. The method for producing an optical film as described in 1 above, wherein the gap is from 0.7 μm to 1.5 μm.

  3. The method for producing an optical film as described in 1 or 2 above, wherein a touch roll is used when the optical film is wound on a winding shaft.

  4). 3. The method for producing an optical film as described in 1 or 2 above, wherein when the optical film is wound on a winding shaft, a near roll and an accompanying air suction device are used.

  5). 5. The method for producing an optical film according to any one of 1 to 4, wherein the optical film has a width of 1000 mm to 2500 mm, a thickness of 15 μm to 50 μm, and a length of 5000 m to 8000 m.

  A method of manufacturing an optical film in which wide, thin, and long optical films are manufactured by high-speed winding to reduce failures such as loosening, winding deviation, and transfer and cooking that occur during storage. Was able to provide.

It is a schematic diagram of the manufacturing apparatus of the melt extrusion type optical film. It is a schematic diagram of a solution casting type film forming apparatus. It is an expansion schematic diagram of the part shown by P of FIG. It is the schematic of the collection | recovery part at the time of using a near roll instead of the touch roll of the accompanying air quantity control apparatus shown in FIG.

  The embodiment of the present invention will be described with reference to FIGS. 1 to 3, but the present invention is not limited to this.

  The method for producing an optical film of the present invention is a method for producing an optical film in which a wide, thin film or long optical film produced by a solution casting method or a melt extrusion method is used as a winding roll body at a high speed on a winding shaft. In addition, when winding, by changing the height of the knurling at both ends of the optical film corresponding to the change in the winding diameter of the roll body, winding occurs when winding, loose winding, misalignment, and transfer occurring during storage It is characterized by producing an optical film with reduced failures such as cooks. In the present invention, both ends of the optical film refer to a range from 0.5 mm to 30 mm from both ends in the width direction of the optical film.

  FIG. 1 is a schematic diagram of an apparatus for producing a melt-extrusion optical film.

  The melt-extrusion method melts a resin to which various additives such as a plasticizer, an ultraviolet absorber, a deterioration inhibitor, a slipping agent, and a peeling accelerator are added as necessary, and the resin melted by an extruder is converted to T It is a method of extruding in a state of widening into a film shape from a slit-like extrusion port of a die, taking it in close contact with the roll surface of a cooling roll, cooling it, forming a film, and winding it on a winding shaft.

  In the figure, reference numeral 1 denotes an optical film manufacturing apparatus. The optical film manufacturing apparatus 1 includes a melt extruding unit 2, a film forming unit 3, a cooling take-up unit 4, a knurling forming unit 5, and a collecting unit 6. The manufacturing apparatus used for the T-die film forming method is not particularly limited, and may be an apparatus to which an additional apparatus such as a stretching apparatus or a heat fixing apparatus is added in addition to the apparatus shown in the figure.

  The melt extrusion unit 2 includes a hopper 201 that supplies a resin for a film, a melting machine 202 that heat-kneads and melts the resin supplied from the hopper 201, a gear pump 203 that stably sends the molten resin to the extrusion unit 3, It has a filter 204 for removing foreign substances, a mixer 205 for uniform mixing of additives, and a supply pipe 206 for resin melted in the T-die 301 of the film forming section 3.

  The film forming unit 3 has a T die 301. The melted resin supplied to the T die 301 by the T die 301 via the supply pipe 206 is extruded into a film form from the slit-like extrusion port of the T die 301 and taken by the cooling take-up unit 4 to be cooled and solidified. It becomes.

  The cooling take-up unit 4 includes a pressing roll 402 that presses the resin extruded into a film shape by the T-die 301 against the cooling roll 401, and a plurality of conveying rolls 403 that convey the unstretched film F cooled and solidified by the cooling roll 401. And have. In addition, you may arrange | position MD (Machine Direction) extending | stretching part and TD (Transverse Direction) extending | stretching part between the cooling take-up part 4 and the knurling formation part 5. FIG.

  The knurling forming section 5 is disposed upstream of the collecting section 6 and has a knurling forming apparatus 501 and a control apparatus 501d (see FIG. 3), and is cooled and solidified unstretched conveyed from the cooling take-up section 4. Knurling is formed on both ends of the film F.

  The collecting unit 6 includes a winder 601 that winds the unstretched film F having knurling formed at both ends in the knurling forming unit 5, an entrained air amount control device 602, a windup shaft rotation number measuring device 603, and the unstretched film F. A contact or non-contact type linear encoder 604 for detecting a traveling speed, a tension control device 605, and a thickness measuring device 606 are provided.

  The winder 601 may be a commonly used one and can be wound by a winding method such as a constant tension method, a constant torque method, a taper tension method, or a program tension control method with a constant internal stress.

  The winding speed of the unstretched film F is preferably 10 m / min to 100 m / min in consideration of productivity and quality. The winding speed is the same when stretched.

  An example of the winding shaft rotational speed measuring machine 603 is Ono Sokki Co., Ltd. rotary encoder.

  Examples of the linear encoder 604 include Ono Sokki Co., Ltd. linear encoder.

  Examples of the thickness measuring device 606 include WEBFREX3 manufactured by Yokogawa Electric Corporation.

  The knurling formation part 5 and the collection | recovery part 6 are demonstrated in detail in FIG.

  As shown in this figure, the resin melted by the melting machine 202 of the melt extrusion unit 2 is widened by a T die 301 through a filter 203, extruded into a film form from an extrusion port, and a cooling roll 401 of the cooling take-up unit 4 To obtain a non-stretched film. Thereafter, after knurling is formed at both ends by the knurling forming unit 5, the optical film is manufactured by winding by the winder 601 at the collecting unit 6.

  FIG. 2 is a schematic view of an apparatus for producing an optical film by a solution casting method.

  The solution casting method is a dope prepared by dissolving a raw material resin in a solvent and adding various additives such as a plasticizer, an ultraviolet absorber, an anti-degradation agent, a slipping agent, and a peeling accelerator as necessary. Is discharged from a die onto an endless metal support (for example, a belt or a drum) that moves indefinitely, and after casting, the solvent is removed to some extent on the endless support, and then peeled off from the endless support Then, the solvent is removed by passing through the drying section by various conveying means, and the product is wound around the winding shaft.

  In the figure, reference numeral 1 'denotes an apparatus for producing an optical film by a solution casting method. The manufacturing apparatus 1 ′ includes a casting part 101 ′, a first drying part 102 ′, an extending part 103 ′, a second drying part 104 ′, a knurling forming part 105 ′, and a collecting part 106 ′. .

  The casting part 101 ′ is an endless mirror belt-like metal casting belt (hereinafter referred to as a belt) 101 ′ a that travels endlessly (in the direction of the arrow in the figure) and a dope obtained by dissolving a resin in a solvent. And a die 101'b cast to 'a. In order to stabilize the dope film flowing out from the die 101′b, a pressure reducing chamber (not shown) is provided upstream of the die 101′b in the belt conveyance direction, and a pressure chamber (not shown) is provided downstream. (Shown) may be provided.

  101'd is a peeling roll formed on the belt 101'a and peeled off the cast film 101'c, and 2 'is a peeled unstretched film.

  The first drying step 102 'is composed of a plurality of sets of a drying box 102'a having a drying air intake port 102'b and a discharge port 102'c, and a pair of upper and lower sides for conveying the unstretched film 2'. A transport roll 102'd.

  It is possible to adjust the amount of solvent contained in the unstretched film 2 ′ before entering the stretching step 103 ′ in the first drying step 102 ′, and it can be installed as necessary.

  The stretching step 103 'includes an MD (Machine Direction) stretching portion 103'a and a TD (Transverse Direction) stretching portion 103'b. The unstretched film 2 'conveyed from the first drying step 102' is stretched.

  The second drying step 104 ′ has the same basic configuration as the first drying step 102 ′, and thus the description thereof is omitted.

  Reference numeral 105 'denotes a knurling forming portion. The knurling forming unit 105 ′ knurles the stretched film 2′a conveyed from the second drying step 104 ′ at both ends of the stretched film 2′a before being wound around the take-up shaft in the winding and collecting step 106 ′. Form. The knurling is formed at both ends of the stretched film 2'a after cutting both ends of the stretched film 2'a held by the TD stretched portion 103'b disposed on the upstream side of the knurling forming portion 105 '. It is preferable to form a knurling. The knurling forming portion 105 'has the same configuration as the knurling forming portion 5 shown in FIG.

  The recovery unit 106 ′ is a knurling unit 105 ′ that winds the stretched film 2′a with the knurling formed at both ends thereof, the winder 106′a, the accompanying air amount control device 106′b, and the travel speed of the stretched film 2′a. A contact or non-contact type linear encoder 106'c, a winding shaft rotational speed measuring device 106'd, a tension control device 106'e, and a thickness measuring device 106 '. . The collection unit 106 'has the same configuration as the collection unit 6 shown in FIG. Moreover, the state of the stretched film wound around the winding shaft is the same as the state of the unstretched film wound around the winding shaft by the collecting unit 6 shown in FIG.

  As the winder 106′a, the same winder as the winder 601 shown in FIG. 1 can be used.

  As shown in the figure, at the casting part 101 ′, the raw material resin is dissolved in a solvent, and various additives such as a plasticizer, an ultraviolet absorber, a deterioration preventing agent, a slipping agent and a peeling accelerator are added to this as necessary. Is added to the endless belt 101'a that moves infinitely, and then the cast film formed by casting is removed to a certain extent on the endless support. Then, after peeling from the belt and passing through the drying section and the stretching section 103 ′ by various conveying means to form a knurling at both ends, an optical film is manufactured by winding it around the winding shaft at the collecting section 106 ′. The

  The present invention relates to a method for producing an optical film by the melt extrusion method shown in FIG. 1 or the solution casting method shown in FIG. The present invention relates to a method for manufacturing an optical film in which failures such as winding looseness, winding deviation, and transfer and cooking that occur during storage are reduced.

  The width of the manufactured optical film shown in FIGS. 1 and 2 is preferably 1000 mm to 2500 mm in consideration of productivity, quality, and the like.

  The thickness is preferably 15 μm to 50 μm in consideration of quality, handling and the like.

  The thickness indicates a value measured with WEBFREX3 manufactured by Yokogawa Electric Corporation.

  The gap (air layer) of the optical film taken up on the take-up shaft is preferably 0.7 μm to 1.5 μm in consideration of the winding quality of the cook and the take-up shaft portion taking into account the core transfer, winding deviation, etc. .

  The gap (air layer) of the optical film refers to the average value of the gap (air layer) between the optical films wound on the winding shaft.

  The gap can be obtained by calculation using the following formulas 1, 2, and 3 by the following method.

The gap (air layer) h _ai of the optical film wound up for a predetermined time is obtained by Equation 1 from the cross-sectional area of the optical film wound up for a predetermined time. The relationship between the speed and the number of rotations can be obtained from Equation 2. The rotational speed c _i of the winding shaft at a predetermined time is obtained from a shaft rotational speed measuring device 603 that counts the motor pulse of the winding shaft, and is detected by the contact speed or non-contact linear encoder 604 × travel time winding length l _i of the strip which speed has been wound around the winding shaft to the time until the n _i of the winding shaft is calculated by. Optical film thickness h _f : 606 Measured with a film thickness measuring device. By substituting the radius r _{i at} the predetermined time, the optical film thickness h _f , and the winding length l _i at the predetermined time into Equation 1, Equation 3 is obtained. Therefore, according to Equation 3, the gap (air layer) of the film being wound can be calculated during winding.

  The length of the optical film wound on the winding shaft 607 (see FIG. 3) is preferably 5000 m to 8000 m in consideration of productivity, winding quality, and the like. The winding length indicates a value calculated from the speed and time.

  FIG. 3 is an enlarged schematic view of a portion indicated by P in FIG. FIG. 3A is an enlarged schematic view showing a knurling forming portion and a recovery portion indicated by P in FIG. FIG. 3B is a schematic block diagram showing the relationship between the knurling forming portion of the portion indicated by P in FIG. 1 and the recovery portion.

  The knurling forming portion 105 ′ and the collecting portion 106 ′ shown in FIG. 2 have the same configurations as the knurling forming portion 5 and the collecting portion 6 shown in FIG. To do.

  The knurling forming unit 5 includes a knurling forming device 501 and a control device 501d. In the knurling forming device 501, a knurling forming roll 501a having an uneven surface having a pressing means 501c and a receiving roll 501b are paired, and an unstretched film F is placed between the knurling forming roll 501a and the receiving roll 501b. By clamping, knurling is formed at both ends of the unstretched film F. The knurling roll 501a can be moved in the vertical direction (arrow direction in the figure) by the pressing means 501c. The moving amount (pressing amount) of the pressing means 501c is controlled by the control device 501d.

  The control device 501d has a memory 501d1 and a CPU 501d2, and an arithmetic process is performed between information input to the CPU 501d2 and information input in advance to the memory 501d1, and a moving amount (pressing amount) of the pressing unit 501c. Is determined, and the moving amount (pressing amount) of the knurling forming roll 501a is determined. When the amount of movement (pressing amount) of the knurling forming roll 501a increases, the height of the knurling formed increases, and when the amount of movement (pressing amount) of the knurling forming roll 501a decreases, the height of the knurling formed decreases. Become.

  In addition, when it has a TD extending | stretching part (not shown) in the upstream with respect to the conveyance direction of the unstretched film F of the knurling formation part 5, the unstretched film F hold | gripped by the TD extending | stretching part (not shown) It is preferable to form a knurling at both ends of the stretched film after cutting both ends at both ends.

  As the knurling forming apparatus 501, a method using a pressing roll and a receiving roll is shown in the drawing, but other than this method, for example, an ink jet method, a laser method, and the like can be given.

  In the present invention, any method can be used for the knurling forming apparatus. For example, in the case of an ink jet system, the discharge amount of the knurling forming material from the ink jet head is controlled. In the case of a laser system, the laser output is controlled.

  The accompanying air amount control device 602 includes a touch roll 602a that contacts and presses an unstretched film F (which may be a stretched film provided with a stretching device) wound on a winding shaft 607, and a touch roll 602a. And a pressing amount control device 602b for controlling the pressing amount, and the accompanying air amount can be adjusted by adjusting the pressing. The pressing amount control device 602b is disposed at both ends of the touch roll 602a.

The relationship between touch rolls and tension control (conveyance tension) can be found in the literature (JK Good Modeling Nip Induced Tension in Wound Rolls), Proceedings of Forth International Conference on Web Handling, 1997).
Based on the concept of TW (winding tension) = Th (conveying tension) + μN (μ: friction coefficient N: touch pressure), it is possible to set the optimal radial stress and circumferential stress during winding that will not cause a failure. Is possible.

  As a material, a metal or a metal roll in which a resin, rubber or the like is wound around can be used. Further, a crown roll having a diameter changed as it goes from the width central portion to the side can also be used. As the core material, AL, iron, CFRP (carbon fiber reinforced plastics) can be used.

  The tension controller 605 includes a tension controller 605a and a moving means 605b of the tension controller 605a. The tension controller 605a adjusts the tension controller 605a according to the change of the unstretched film F wound on the winding shaft 607 in the collecting unit 6. The position can be moved (arrow direction in the figure). In general, the tension is set to be low at the beginning of winding and to increase as the winding diameter increases.

  Hereinafter, the relationship between the members constituting the knurling forming portion 5 and the collecting portion 6 will be described with reference to FIG. Measurement information of the take-up shaft rotation number measuring machine 603 is input to the CPU 501d2 of the control device 501d. The measurement information of the linear encoder 604 is input to the CPU 501d2 of the control device 501d. Measurement information of the thickness measuring device 606 is input to the CPU 501d2 of the control device 501d. Calculation processing is performed based on the measurement information of the winding shaft rotation number measuring machine 603, the linear encoder 604, and the measurement information of the thickness measuring device 606, the winding length is calculated, and information on the thickness and the winding shaft rotation is obtained. Thus, the winding diameter is calculated.

  On the other hand, in the memory 501d1, information on the gap (air layer) of the film set as a production condition is input from the thickness of the optical film to be manufactured in advance, the winding length, the amount of entrained air, and the knurling height.

  A calculation process is performed based on the measured winding diameter information of the CPU 501d2 and the set winding diameter information of the memory 501d1, and a difference between the set film gap (air layer) is calculated.

The calculated information is fed back to the pressing means 501c of the knurling forming apparatus 501, and the knurling height is feedback-controlled. That is, when it is smaller than the gap (air layer) of the setting film, the pressing means 501c of the knurling forming device 501 increases the pressure of the knurling roll 501a to increase the knurling height, and the gap (air layer) of the setting film. In the case of being large, the pressing means 501c of the knurling forming apparatus 501 can be wound with the gap of the optical film of the roll body made constant by lowering the pressing of the knurling forming roll 501a and lowering the knurling height. (The winding diameter with respect to the winding length can be made constant.)
The method for feedback control of the knurling height shown in this figure can be applied even in the case of a near roll.

  FIG. 4 is a schematic view of the collection unit when a near roll is used instead of the touch roll of the accompanying air amount control device shown in FIG.

  In the figure, reference numeral 602 'denotes an entrained air amount control device. The accompanying air amount control device 602 'has a near roll 602'a and an accompanying air suction device 602'c.

  The near roll 602′a is wound around the take-up shaft 606 with a gap E between the unstretched film F taken up by the take-up shaft 606 and the unstretched film F taken up by the take-up shaft 606. The unstretched film F is disposed so as to have a holding angle.

  Reference numeral 602'b denotes a position control device for the near roll 602'a. The position of the near roll 602'a can be changed (in the direction of the arrow in the figure), and it is constant even when the winding progresses and the winding diameter increases. Adjustment is made so as to maintain the gap E. The position control device 602′b is disposed at both ends of the near roll 602′a. The accompanying air suction device 602'c has a suction nozzle 602'c1 having a suction pipe 602'c2, and the amount of accompanying air can be adjusted by sucking the gap E with the suction nozzle 602'c1. It has become. The suction nozzle 602'c1 can be moved (in the direction of the arrow in the figure) in synchronization with the position of the near roll 602'a in accordance with the diameter of the unstretched film F wound on the winding shaft 606. .

  Even when the near roll 602'a shown in this figure is used, the method for feedback control of the knurling height shown in FIG. 3 can be applied.

  In addition, although this figure is attached and demonstrated to the unstretched film F, when the extending | stretching apparatus is arrange | positioned, of course, the case of a stretched film is also possible.

Then, as shown in FIGS. 3 and 4, the optical film is wound around the winding shaft by control provided while changing the height of the knurling at both ends of the optical film corresponding to the change in the winding diameter of the roll body during winding. The following effects can be given.
1. Horse back failure, winding that occurs during winding even if a thin film of 10 to 50 μm, a wide width of 1000 to 2500 mm, a long optical film of 5000 to 8000 m is wound at a high speed of 60 to 130 m / min. It has become possible to produce an optical film with reduced failures such as loosening, winding misalignment, transfer occurring during storage, and cooking.
2. It has become possible to satisfy the requirements for optical properties such as haze and letter value as optical films for high-definition liquid crystal display devices.
Even if it is stored for a long time of 3.6 months or longer, the optical characteristics do not change, and it is possible to produce an optical film in which no failure occurs.

  Next, materials related to the method for producing an optical film of the present invention will be described.

(Thermoplastic resin)
The thermoplastic resin used in the method for producing an optical film of the present invention is not particularly limited as long as it can be formed by a solution casting method or a melt casting method. Here, the “thermoplastic resin” refers to a resin that becomes soft when heated to the glass transition temperature or the melting point and can be molded into a desired shape.

  As thermoplastic resins, general-purpose resins include cellulose ester resins, polyethylene (PE), high density polyethylene, medium density polyethylene, low density polyethylene, polypropylene (PP), polyvinyl chloride (PVC), and polyvinylidene chloride. , Polystyrene (PS), polyvinyl acetate (PVAc), Teflon (registered trademark) (polytetrafluoroethylene, PTFE), ABS resin (acrylonitrile butadiene styrene resin), AS resin, acrylic resin (PMMA), cycloolefin resin And polyester resins.

  In addition, polyamide (PA), nylon, polyacetal (POM), polycarbonate (PC) resin, modified polyphenylene ether (m-PPE, modified PPE, PPO), polybutylene terephthalate are required when strength and resistance to breakage are particularly required. (PBT), polyethylene terephthalate (PET), glass fiber reinforced polyethylene terephthalate (GF-PET), cyclic polyolefin (COP), and the like can be used.

  When higher heat distortion temperature and long-term use characteristics are required, polyphenylene sulfide (PPS), polytetrafluoroethylene (PTFE), polysulfone, polyethersulfone, amorphous polyarylate, liquid crystal polymer, polyetherether Ketone, thermoplastic polyimide (PI), polyamideimide (PAI), and the like can be used. In addition, it is possible to perform combination of the kind of resin and molecular weight according to the use of a thermoplastic resin film.

  Hereinafter, typical examples of thermoplastic resins that can be suitably used in the present invention will be described.

<Cellulose ester resin>
The cellulose ester resin according to the method for producing a thermoplastic resin film of the present invention is preferably contained in a cellulose ester film for optical film use, and is preferably a cellulose ester having an aliphatic acyl group having 2 or more carbon atoms. More preferably, the cellulose ester has a total acyl substitution degree of 1.0 to 2.95 and a total acyl group carbon number of 2.0 to 9.5.

  The total number of acyl groups in the cellulose ester is preferably 4.0 to 9.0, and more preferably 5.0 to 8.5. However, the acyl group total carbon number is the sum total of the products of the substitution degree and the carbon number of each acyl group substituted in the glucose unit of the cellulose ester.

  Furthermore, the number of carbon atoms of the aliphatic acyl group is preferably 2 or more and 6 or less, more preferably 2 or more and 4 or less, from the viewpoint of productivity and cost of cellulose synthesis. The portion not substituted with an acyl group usually exists as a hydroxyl group.

  Glucose units constituting cellulose with β-1,4-glycoside bonds have free hydroxyl groups at the 2nd, 3rd and 6th positions. The cellulose ester in the present invention is a polymer obtained by esterifying some or all of these hydroxyl groups with an acyl group. The acyl group substitution degree represents the total of the proportions of cellulose esterified at the 2nd, 3rd and 6th positions of the repeating unit. Specifically, the degree of substitution is 1 when the hydroxyl groups at the 2-position, 3-position and 6-position of cellulose are 100% esterified. Therefore, when all of the 2nd, 3rd and 6th positions of cellulose are 100% esterified, the degree of substitution is 3 at the maximum.

  Examples of the acyl group include an acetyl group, a propionyl group, a butyryl group, a pentanate group, and a hexanate group. Examples of the cellulose ester include cellulose acetate, cellulose propionate, cellulose butyrate, and cellulose pentanate. . Further, mixed fatty acid esters such as cellulose acetate, cellulose acetate propionate, cellulose propionate, cellulose acetate butyrate, and cellulose acetate pentanate may be used as long as the above-mentioned side chain carbon number is satisfied. Among these, cellulose acetate, cellulose acetate propionate, and cellulose propionate are particularly preferable cellulose esters for optical film applications.

  Preferred cellulose esters other than cellulose triacetate have an acyl group having 2 to 4 carbon atoms as a substituent, and when the substitution degree of acetyl group is X and the substitution degree of propionyl group or butyryl group is Y, the following formula ( It is a cellulose ester resin containing a cellulose ester that simultaneously satisfies I) and (II).

Formula (I) 1.2 ≦ X + Y ≦ 2.95
Formula (II) 0 ≦ X ≦ 2.5
Of these, cellulose acetate propionate is particularly preferably used, and 0.1 ≦ X ≦ 2.5 and 0.1 ≦ Y ≦ 2.8 are particularly preferable. The portion that is not substituted with an acyl group usually exists as a hydroxyl group. The measuring method of acyl group substitution degree can be measured according to ASTM-D817-96.

  The cellulose ester resin according to the method for producing a thermoplastic resin film of the present invention preferably has a weight average molecular weight Mw of 50,000 to 500,000, more preferably 100,000 to 300,000, and still more preferably 150,000 to 250,000.

  Since the average molecular weight and molecular weight distribution of the cellulose ester resin can be measured using high performance liquid chromatography, the weight average molecular weight (Mw) and molecular weight distribution are calculated using this.

  The measurement conditions are as follows.

Solvent: Methylene chloride Column: Shodex K806, K805, K803G (Used by connecting three Showa Denko Co., Ltd.)
Column temperature: 25 ° C
Sample concentration: 0.1% by mass
Detector: RI Model 504 (GL Science Co., Ltd.)
Pump: L6000 (manufactured by Hitachi, Ltd.)
Flow rate: 1.0 ml / min
Calibration curve: Standard polystyrene STK standard polystyrene (manufactured by Tosoh Corporation)
A calibration curve with 13 samples from Mw = 1000000 to 500 was used. The 13 samples are preferably used at approximately equal intervals.

  The raw material cellulose of the cellulose ester resin according to the method for producing a thermoplastic resin film of the present invention may be wood pulp or cotton linter, and the wood pulp may be softwood or hardwood. Softwood pulp is preferably used. The cellulose ester made from these can be mixed suitably or can be used independently.

  For example, the ratio of cellulose ester derived from cellulose linter: cellulose ester derived from wood pulp (coniferous): cellulose ester derived from wood pulp (hardwood) is 100: 0: 0, 90: 10: 0, 85: 15: 0, 50:50: 0, 20: 80: 0, 10: 90: 0, 0: 100: 0, 0: 0: 100, 80:10:10, 85: 0: 15, 40:30:30.

  In the present invention, any one containing cellulose having a high degree of polymerization such as wood pulp and linter may be used. For example, linter pulp is preferable, and cellulose composed of at least linter pulp is preferably used. The α-cellulose content, which is an index of the crystallinity of cellulose, is 90% or more (for example, about 92% to 100%, preferably 95% to 100%, more preferably about 99.5% to 100%). .

<Acrylic resin>
Acrylic resins that can be used in the present invention include methacrylic resins. Although it does not restrict | limit especially as resin, What consists of 50 to 99 mass% of methyl methacrylate units and 1 to 50 mass% of other monomer units copolymerizable with this is preferable.

  Other monomers that can be copolymerized include alkyl methacrylates having 2 to 18 alkyl atoms, alkyl acrylates having 1 to 18 carbon atoms, acrylic acid, methacrylic acid, and the like. Saturated acids, maleic acids, fumaric acids, unsaturated divalent carboxylic acids such as itaconic acid, aromatic vinyl compounds such as styrene, α-methylstyrene, and nucleus-substituted styrene, α, β- such as acrylonitrile, methacrylonitrile, etc. Examples thereof include unsaturated nitrile, maleic anhydride, maleimide, N-substituted maleimide, glutaric anhydride, and the like. These may be used alone or in combination of two or more.

  Among these, methyl acrylate, ethyl acrylate, n-propyl acrylate, n-butyl acrylate, s-butyl acrylate, 2-ethylhexyl acrylate, and the like are preferable, and methyl acrylate and n-butyl acrylate are particularly preferably used.

  A commercially available thing can also be used as acrylic resin. For example, Delpet 60N, 80N (Asahi Kasei Chemicals Co., Ltd.), Dianal BR52, BR80, BR83, BR85, BR88 (Mitsubishi Rayon Co., Ltd.), KT75 (Denki Kagaku Kogyo Co., Ltd.) and the like can be mentioned. .

<Acrylic polymer with lactone ring structure>
The acrylic resin that can be used in the present invention includes an acrylic polymer having a lactone ring structure.

  The acrylic polymer having a lactone ring structure preferably has a lactone ring structure represented by the following general formula (1).

(Wherein R ¹ , R ² and R ³ each independently represents a hydrogen atom or an organic residue having 1 to 20 carbon atoms.)
Examples of the organic residue represented by R ¹ include an alkyl group having 1 to 18 carbon atoms, a cycloalkyl group having 3 to 10 carbon atoms, and an aryl group. R ² is preferably a hydrogen atom.

Examples of the organic residue represented by R ² include an alkyl group having 1 to 18 carbon atoms, a cycloalkyl group having 3 to 10 carbon atoms, an aryl group, a hydroxyalkyl group having 1 to 8 carbon atoms, and — (CH ₂ ). _{^{mNR 11 R 12, - (CH}} 2) mN (R 11 R 12 R 13) + · M -, or ^{_{(C 2 H 4 O) pR}} 14 , and the like. Here, R ¹¹ , R ¹² and R ¹³ may be the same or different and each is an alkyl group having 1 to 8 carbon atoms, R ¹⁴ is an alkyl group having 1 to 18 carbon atoms, and m = 2 To 5, p = 1 to 80, and M ⁻ is Cl ⁻ , Br ⁻ , SO ₄ ²⁻ , PO ₄ ³⁻ , CH ₃ COO ⁻ or HCOO ⁻ . R ² is preferably a hydrogen atom or an alkyl group having 1 to 18 carbon atoms, more preferably a hydrogen atom, a methyl group, or an ethyl group.

Examples of the organic residue represented by R ³ include an alkyl group having 1 to 18 carbon atoms, a cycloalkyl group having 3 to 10 carbon atoms, an aryl group, and a hydroxyalkyl group having 1 to 8 carbon atoms. R ³ is preferably a hydrogen atom, an alkyl group having 1 to 18 carbon atoms, or a hydroxyalkyl group having 1 to 8 carbon atoms, more preferably a hydrogen atom, a methyl group, or a 2-hydroxyethyl group.

  The content ratio of the acrylic polymer having a lactone ring structure represented by the general formula (1) is preferably 5% by mass to 90% by mass with respect to the total of the acrylic polymer having a lactone ring structure and the cellulose ester resin. More preferably, it is 10 mass% to 70 mass%, More preferably, it is 10 mass% to 60 mass%, Most preferably, it is 10 mass% to 50 mass%.

  An acrylic polymer having a lactone ring structure may be included in combination with another acrylic polymer, and an acrylic polymer comprising an acrylic polymer having a lactone ring structure and another acrylic polymer. The content ratio of the total amount of the polymer is preferably 5% by mass to 90% by mass, more preferably 10% by mass to 70% by mass, still more preferably 10% by mass to 60% by mass, and particularly preferably 10% by mass to 50% by mass. %.

  The acrylic polymer having a lactone ring structure may have a structure other than the lactone ring structure represented by the general formula (1). The structure other than the lactone ring structure represented by the general formula (1) is not particularly limited, but a (meth) acrylic acid ester, a hydroxyl group, which will be described later as a method for producing an acrylic polymer having a lactone ring. Polymer structural units (repeating structural units) constructed by polymerizing at least one selected from (hydroxyl group) -containing monomers, unsaturated carboxylic acids, and monomers represented by the following general formula (2) are preferred.

(Wherein R ⁴ represents a hydrogen atom or a methyl group, X represents a hydrogen atom, an alkyl group having 1 to 20 carbon atoms, an aryl group, an —OAc group, a —CN group, a —CO—R ⁵ group, or a C— Represents an O—R ⁶ group, an Ac group represents an acetyl group, and R ⁵ and R ⁶ represent a hydrogen atom or an organic residue having 1 to 20 carbon atoms.)
<Cycloolefin resin>
In the present invention, it is also preferable to use a cyclo (hereinafter also referred to as “cyclic”) olefin resin. Examples of cycloolefin resins include norbornene resins, monocyclic olefin resins, cyclic conjugated diene resins, vinyl alicyclic hydrocarbon resins, and hydrides thereof. Among these, norbornene-based resins can be suitably used because of their good transparency and moldability.

  Examples of the norbornene-based resin include a ring-opening polymer of a monomer having a norbornene structure, a ring-opening copolymer of a monomer having a norbornene structure and another monomer, a hydride thereof, and a norbornene structure. An addition polymer of a monomer having a monomer, an addition copolymer of a monomer having a norbornene structure and another monomer, a hydride thereof, or the like can be given.

  Among these, a ring-opening (co) polymer hydride of a monomer having a norbornene structure is particularly suitable from the viewpoints of transparency, moldability, heat resistance, low hygroscopicity, dimensional stability, lightness, and the like. Can be used.

Examples of the monomer having a norbornene structure include bicyclo [2.2.1] hept-2-ene (common name: norbornene) and tricyclo [4.3.0.1 ^2,5 ] deca-3,7-diene. (Common name: dicyclopentadiene), 7,8-benzotricyclo [4.3.0.1 ^2,5 ] dec-3-ene (common name: methanotetrahydrofluorene), tetracyclo [4.4.0. 1 ^2,5 . ^{17, 10} ] dodec-3-ene (common name: tetracyclododecene), and derivatives of these compounds (for example, those having a substituent in the ring). Here, examples of the substituent include an alkyl group, an alkylene group, and a polar group. Moreover, these substituents may be the same or different and a plurality thereof may be bonded to the ring. Monomers having a norbornene structure can be used singly or in combination of two or more.

  Examples of the polar group include a hetero atom or an atomic group having a hetero atom. Examples of the hetero atom include an oxygen atom, a nitrogen atom, a sulfur atom, a silicon atom, and a halogen atom. Specific examples of the polar group include a carboxyl group, a carbonyloxycarbonyl group, an epoxy group, a hydroxyl group, an oxy group, an ester group, a silanol group, a silyl group, an amino group, a nitrile group, and a sulfone group.

  Other monomers capable of ring-opening copolymerization with monomers having a norbornene structure include monocyclic olefins such as cyclohexene, cycloheptene, and cyclooctene and derivatives thereof, cyclic conjugated dienes such as cyclohexadiene, cycloheptadiene, and the like. And derivatives thereof.

  A ring-opening polymer of a monomer having a norbornene structure and a ring-opening copolymer of a monomer having a norbornene structure and another monomer copolymerizable with the monomer have a known ring-opening polymerization catalyst. It can be obtained by (co) polymerization in the presence.

  Examples of other monomers that can be addition copolymerized with a monomer having a norbornene structure include α-olefins having 2 to 20 carbon atoms such as ethylene, propylene, and 1-butene, and derivatives thereof; cyclobutene, cyclopentene, Cycloolefins such as cyclohexene and derivatives thereof; non-conjugated dienes such as 1,4-hexadiene, 4-methyl-1,4-hexadiene, 5-methyl-1,4-hexadiene, and the like. These monomers can be used alone or in combination of two or more. Among these, α-olefin is preferable and ethylene is more preferable.

  An addition polymer of a monomer having a norbornene structure and an addition copolymer of another monomer copolymerizable with a monomer having a norbornene structure can be used in the presence of a known addition polymerization catalyst. It can be obtained by polymerization.

  A hydrogenated product of a ring-opening polymer of a monomer having a norbornene structure, a hydrogenated product of a ring-opening copolymer of a monomer having a norbornene structure and another monomer capable of ring-opening copolymerization thereof, Hydrogenated products of addition polymers of monomers having a norbornene structure, and hydrogenated products of addition copolymers of monomers having a norbornene structure and other monomers capable of addition copolymerization with these A known hydrogenation catalyst containing a transition metal such as nickel or palladium is added to the polymer solution, and the carbon-carbon unsaturated bond is preferably hydrogenated by 90% or more.

Among norbornene-based resins, as repeating units, X: bicyclo [3.3.0] octane-2,4-diyl-ethylene structure and Y: tricyclo [4.3.0.1 ^2,5 ] decane-7 , 9-diyl-ethylene structure, the content of these repeating units is 90% by mass or more based on the entire repeating units of the norbornene resin, and the content ratio of X and the content ratio of Y The ratio of X: Y is preferably 100: 0 to 40:60. By using such a resin, it is possible to obtain a light confinement film having no dimensional change over a long period of time and excellent optical property stability.

  The molecular weight of the cyclic olefin resin used in the present invention is appropriately selected according to the purpose of use. Polyisoprene or polystyrene-equivalent weight average molecular weight (Mw) measured by gel permeation chromatography using cyclohexane (toluene if the polymer resin is not dissolved) as a solvent, usually 20,000 to 150,000. . Preferably it is 25,000 to 100,000, more preferably 30,000 to 80,000. When the weight average molecular weight is in such a range, the mechanical strength and molding processability of the film are highly balanced and suitable.

  What is necessary is just to select the glass transition temperature of cyclic olefin resin suitably according to the intended purpose. From the viewpoint of durability and stretch processability, it is preferably in the range of 130 ° C to 160 ° C, more preferably 135 ° C to 150 ° C.

  The molecular weight distribution (weight average molecular weight (Mw) / number average molecular weight (Mn)) of the cyclic olefin-based resin is 1.2 to 3.5, preferably 1.5 to 3.3 from the viewpoint of relaxation time, productivity, and the like. 0, more preferably 1.8 to 2.7.

The cyclic olefin resin used in the present invention preferably has an absolute value of photoelastic coefficient of 10 × 10 ⁻¹² Pa ⁻¹ or less, more preferably 7 × 10 ⁻¹² Pa ⁻¹ or less, and 4 ×. It is particularly preferably 10 ⁻¹² Pa ⁻¹ or less. The photoelastic coefficient C is a value represented by C = Δn / σ where birefringence is Δn and stress is σ.

  In the present invention, it is preferable that the cyclic olefin-based resin does not substantially contain particles. Here, “substantially free of particles” means that even if particles are added to a film made of a cyclic olefin resin, the amount of increase in haze from the unadded state is within a range of 0.05% or less. Means acceptable. In particular, since alicyclic polyolefin resin lacks affinity with many organic particles and inorganic particles, when a cyclic olefin thermoplastic resin film to which particles exceeding the above range are added is stretched, voids are easily generated. As a result, the haze may be significantly reduced.

<Polycarbonate resin>
In the present invention, various known polycarbonate resins can also be used. In the present invention, it is particularly preferable to use an aromatic polycarbonate. There is no restriction | limiting in particular about the said aromatic polycarbonate, and there will be no restriction | limiting in particular if it is an aromatic polycarbonate from which the various characteristics of a desired film are acquired.

  In general, a polymer material collectively referred to as polycarbonate is a generic term for a polymer material in which a polycondensation reaction is used in its synthesis method and the main chain is linked by a carbonic acid bond. , Phosgene, diphenyl carbonate and the like obtained by polycondensation. Usually, an aromatic polycarbonate represented by a repeating unit having 2,2-bis (4-hydroxyphenyl) propane called bisphenol-A as a bisphenol component is preferably selected, and various bisphenol derivatives should be appropriately selected. Thus, an aromatic polycarbonate copolymer can be formed.

  In addition to this bisphenol-A, bis (4-hydroxyphenyl) methane, 1,1-bis (4-hydroxyphenyl) cyclohexane, 9,9-bis (4-hydroxyphenyl) fluorene, 1,1 -Bis (4-hydroxyphenyl) -3,3,5-trimethylcyclohexane, 2,2-bis (4-hydroxy-3-methylphenyl) propane, 2,2-bis (4-hydroxyphenyl) -2-phenyl Ethane, 2,2-bis (4-hydroxyphenyl) -1,1,1,3,3,3-hexafluoropropane, bis (4-hydroxyphenyl) diphenylmethane, bis (4-hydroxyphenyl) sulfide, bis ( 4-hydroxyphenyl) sulfone, 1,1-bis (4-hydroxyphenyl) -3,3,5-tri It can be mentioned chill cyclohexane, and the like.

  It is also possible to use an aromatic polyester carbonate partially containing terephthalic acid and / or isophthalic acid components. By using such a structural unit as a part of the structural component of the aromatic polycarbonate composed of bisphenol-A, the properties of the aromatic polycarbonate, such as heat resistance and solubility, can be improved. The present invention is also effective for coalescence.

  If the aromatic polycarbonate used here has a viscosity average molecular weight of 10,000 or more and 200,000 or less, it is suitably used. A viscosity average molecular weight of 20,000 to 120,000 is particularly preferred. If a resin having a viscosity average molecular weight lower than 10,000 is used, the mechanical strength of the obtained film may be insufficient, and if it has a high molecular weight of 400000 or more, the viscosity of the dope becomes too high, which causes problems in handling. The viscosity average molecular weight can be measured by commercially available high performance liquid chromatography.

  The glass transition temperature of the aromatic polycarbonate according to the present invention is preferably 200 ° C. or higher in order to obtain a highly heat-resistant film, and more preferably 230 ° C. or higher. These can be obtained by appropriately selecting the copolymerization component. The glass transition temperature can be measured with a DSC apparatus (differential scanning calorimetry apparatus). For example, the baseline is unevenly determined by a temperature rise condition of 10 ° C./min with RDC220 manufactured by Seiko Instruments Inc. It is the temperature that begins to do.

<Polyester resin>
The polyester-based resin that can be used in the present invention is obtained by polymerizing a dicarboxylic acid and a diol, and 70% or more of the dicarboxylic acid structural unit (the structural unit derived from the dicarboxylic acid) is derived from the aromatic dicarboxylic acid, And 70% or more of diol structural units (constituent units derived from diol) are derived from aliphatic diols.

  The proportion of the structural unit derived from the aromatic dicarboxylic acid is 70% or more, preferably 80% or more, and more preferably 90% or more.

  The proportion of the structural unit derived from the aliphatic diol is 70% or more, preferably 80% or more, more preferably 90% or more. Two or more kinds of polyester resins may be used in combination.

  Examples of the aromatic dicarboxylic acid include terephthalic acid, isophthalic acid, 2,6-naphthalenedicarboxylic acid, 1,5-naphthalenedicarboxylic acid, naphthalenedicarboxylic acid such as 2,7-naphthalenedicarboxylic acid, and 4,4′-biphenyldicarboxylic acid. 3,4'-biphenyldicarboxylic acid and the like, and ester-forming derivatives thereof.

  As the polyester resin, aliphatic dicarboxylic acids such as adipic acid, azelaic acid, and sebacic acid, and monocarboxylic acids such as benzoic acid, propionic acid, and butyric acid can be used without departing from the object of the present invention.

  Examples of the aliphatic diol include ethylene glycol, 1,3-propylene diol, 1,4-butanediol, 1,4-cyclohexanedimethanol, 1,6-hexanediol, and ester-forming derivatives thereof.

  As the polyester resin, monoalcohols such as butyl alcohol, hexyl alcohol, and octyl alcohol, and polyhydric alcohols such as trimethylolpropane, glycerin, and pentaerythritol can be used as long as the object of the present invention is not impaired.

  For the production of the polyester-based resin, a direct esterification method or a transesterification method, which are known methods, can be applied. Polycondensation catalysts used in the production of polyester resins include known antimony compounds such as antimony trioxide and antimony pentoxide, germanium compounds such as germanium oxide, titanium compounds such as titanium acetate, and aluminum compounds such as aluminum chloride. Although it can illustrate, it is not limited to these.

  Preferred polyester resins include polyethylene terephthalate resin, polyethylene terephthalate-isophthalate copolymer resin, polyethylene-1,4-cyclohexanedimethylene-terephthalate copolymer resin, polyethylene-2,6-naphthalene dicarboxylate resin, polyethylene-2 , 6-Naphthalenedicarboxylate-terephthalate copolymer resin, polyethylene-terephthalate-4,4'-biphenyldicarboxylate resin, poly-1,3-propylene-terephthalate resin, polybutylene terephthalate resin, polybutylene-2,6- Naphthalene dicarboxylate resin.

  More preferable polyester resins include polyethylene terephthalate resin, polyethylene terephthalate-isophthalate copolymer resin, polyethylene-1,4-cyclohexanedimethylene-terephthalate copolymer resin, polybutylene terephthalate resin, and polyethylene-2,6-naphthalene dicarboxylate. A rate resin is mentioned.

  The intrinsic viscosity of the polyester-based resin (phenol / 1,1,2,2-tetrachloroethane = value measured at 25 ° C. in a 60/40 mass ratio mixed solvent) is 0.7 dl / g to 2.0 dl / g. Preferably, it is 0.8 dl / g to 1.5 dl / g. Since the molecular weight of the polyester resin is sufficiently high when the intrinsic viscosity is 0.7 or more, the molded product made of the polyester resin composition obtained using the polyester resin has mechanical properties necessary as a molded product. , Transparency becomes good. When the intrinsic viscosity is 2.0 or less, the moldability is good.

(Additive)
In the method for producing a thermoplastic dendritic film of the present invention, as additives, an ester plasticizer having a structure in which an organic acid and a trihydric or higher alcohol are condensed, an ester system comprising a polyhydric alcohol and a monovalent carboxylic acid are used. At least one selected from a plasticizer, an ester plasticizer comprising a polyvalent carboxylic acid and a monohydric alcohol, a phenolic antioxidant, a hindered amine light stabilizer, a phosphorus stabilizer, and a sulfur stabilizer. It is preferable to contain a kind of stabilizer, and in addition to this, a peroxide decomposer, radical scavenger, metal deactivator, ultraviolet absorber, matting agent, dye, pigment, and other plasticizers Further, an antioxidant other than the hindered phenol antioxidant may be included.

(Organic solvent)
The organic solvent useful for forming a dope for production by the solution casting method can be used without limitation as long as it dissolves acrylic resin, cellulose ester resin, and other additives simultaneously.

  For example, as the chlorinated organic solvent, methylene chloride, as the non-chlorinated organic solvent, methyl acetate, ethyl acetate, amyl acetate, acetone, tetrahydrofuran, 1,3-dioxolane, 1,4-dioxane, cyclohexanone, ethyl formate, 2,2,2-trifluoroethanol, 2,2,3,3-hexafluoro-1-propanol, 1,3-difluoro-2-propanol, 1,1,1,3,3,3-hexafluoro- Examples include 2-methyl-2-propanol, 1,1,1,3,3,3-hexafluoro-2-propanol, 2,2,3,3,3-pentafluoro-1-propanol, and nitroethane. Methylene chloride, methyl acetate, ethyl acetate and acetone can be preferably used.

  In addition to the organic solvent, the dope preferably contains 1 to 40% by mass of a linear or branched aliphatic alcohol having 1 to 4 carbon atoms. When the proportion of alcohol in the dope increases, the web gels and peeling from the metal support becomes easy, and when the proportion of alcohol is small, the acrylic resin and cellulose ester resin dissolve in a non-chlorine organic solvent system. There is also a role to promote. In particular, in a solvent containing methylene chloride and a linear or branched aliphatic alcohol having 1 to 4 carbon atoms, an acrylic resin, a cellulose ester resin, and acrylic particles are used in an amount of at least 15% by mass in total. A dope composition in which 45% by mass is dissolved is preferable. Examples of the linear or branched aliphatic alcohol having 1 to 4 carbon atoms include methanol, ethanol, n-propanol, iso-propanol, n-butanol, sec-butanol, and tert-butanol. Ethanol is preferred because of the stability of these dopes, the relatively low boiling point, and good drying properties.

  EXAMPLES Hereinafter, the present invention will be specifically described with reference to examples, but the present invention is not limited thereto.

Example 1
(Preparation of dope)
Cellulose acetate propionate 100 parts by mass (acetyl group substitution degree + propionyl group substitution degree = 2.45, number average molecular weight (Mn) = 60000, weight average molecular weight (Mw) = 18000, Mw / Mn = 3.00)
Triphenyl phosphate 8 parts by weight Ethylphthalyl ethyl glycolate 2 parts by weight Methylene chloride 360 parts by weight Ethanol 60 parts by weight Tinuvin 109 (manufactured by BASF Japan) 0.5 part by weight Tinuvin 171 (manufactured by BASF Japan) 0.5 parts by mass Aerosil 972V (manufactured by Nippon Aerosil Co., Ltd.) 0.2 parts by mass The material having the above dope composition was put into a sealed container, heated and stirred, and completely dissolved and filtered. The filtration was performed through a sintered metal filter (capture particle size = 10 microns) after filtration by a filter press. Silicon dioxide fine particles (Aerosil R972V) were added after being dispersed in ethanol.

(Preparation of optical film (sample No. 101))
The prepared dope is cast by the manufacturing apparatus shown in FIG. 2 having the knurling part and the recovery part shown in FIG. 3, and is cast on an endless belt-like supporter with a wet film thickness of 300 μm and a width of 1500 mm. After forming the cast film, the cast film is peeled from the endless belt-like support, dried in a drying step, MD stretched at a stretch ratio of 1.0%, and then TD stretched at a stretch ratio of 40.0%. When a roll body of an optical film is produced by winding on a take-up shaft, the take-up shaft rotational speed measuring device, the winding diameter measuring device, and the thickness when taking up on the take-up shaft according to the block diagram shown in FIG. The information from the measuring device is input to the control device, and the processed information is fed back to the knurling forming section, and shown in Table 1 at both ends of the optical film corresponding to the variation of the winding diameter (relative to the set winding diameter). Roll body while changing the height of the knurling The winding shaft such that a gap of the optical film is 1.0 .mu.m ± 0.5, samples were produced thickness 40 [mu] m, width 1900 mm, the take-up roll of the length 8000 m No. 101.

  The gap (air layer) of the optical film of the roll body is set in advance as a production condition, and is compared with the value obtained by calculation from the winding length, the film thickness, the speed, and the number of revolutions on the basis of the formula 3 in the specification text online. .

  In addition, the thickness of the optical film was 40 μm, and the length of the optical film of one roll was 5200 m. Ono Sokki Co., Ltd. rotary encoder was used as the winding shaft rotational speed measuring machine.

  As a dry thickness measuring apparatus, a non-contact online film thickness meter (WEBFREX3 manufactured by Yokogawa Electric Corporation) using X-rays was used.

(Casting conditions)
The maximum fluctuation width between the dope outlet of the die and the endless belt-like support was 100 μm. The fluctuation range of the height was performed by controlling the belt tension after providing the back roll. The fluctuation range is a value measured by a laser displacement meter manufactured by Keyence Corporation.

Endless belt-like support Material: Stainless steel (SUS316) Width: 1800mm
Rotational speed (moving speed): 100m / min
Casting width: 1500mm
Surface temperature: 20 ° C
(Knurling conditions)
Knurling forming apparatus: A system in which a knurling forming roll and a receiving roll are paired as shown in FIG.

Material of knurling roll: Material SKT4 Hardness HRC40
Surface shape of the knurling roll: The mountain shape is a 120 ° quadrangular frustum shape, which is regularly arranged with a minute interval, and is slanted so that the side of the bottom surface is at an angle of 45 degrees with the longitudinal direction of the web A shape that is arranged and lined up to a width of 10 mm in the width direction.

Diameter of knurling roll: 300 mm
Receiving roll diameter: 200 mm
Material of receiving roll: surface hard-plated metal roll Winding condition Touch roll: 120 mm in diameter, 2600 mm in length
Touch roll material: NBR rubber (Maywa Rubber Industrial Co., Ltd.) White Elecon
Hardness 35 degrees, thickness 10 mm, CFRP (Carbon Fiber Reinforced Plastics) core Touch roll pressure: 50 N / m
Winding tension: Initial tension 250N / m Taper 90% Corner 25%
Winding speed: 100 m / min
Winding shaft diameter: 6 inches Material of winding shaft: FRP (Fiber Reinforced Plastics)
(Production of optical film (Comparative sample No. 102, 103, 104))
Sample No. 5 was used except that the height of the knurling was kept constant at 5.0 μm, 4.0 μm, and 3.0 μm. Under the same conditions as in 101, an optical film is used as a winding roll body on the winding shaft, and comparative sample No. 102, 103, and 104.

Evaluation The produced sample No. Table 2 shows the results obtained by measuring the back failure, winding looseness, winding deviation, transfer, and cooking of the horses 101 to 104 by the following methods and evaluating them according to the following evaluation ranks.

Measuring method of horse back failure,
After storage for about 10 days at 40 ° C. and 80% temperature and humidity, the length of depression of the central recess was measured on a scale with reference to the end.

Evaluation rank of horse back failure ○: Less than 2mm △: Less than 3mm, 2mm or less ×: 3mm or more Measuring method of winding looseness After storing for 10 days under 40 ℃, 80% temperature and humidity, the upper and lower winding diameters are scaled Then, three locations in the width direction were measured.

Evaluation rank of winding looseness ○: Upper and lower winding diameter difference is less than 2 mm △: Upper and lower winding diameter difference is 2 mm or more and less than 4 mm ×: Upper and lower winding diameter difference is 4 mm or more Winding deviation measuring method 40 ° C., 80% temperature and humidity After storing for about 10 days below, an acceleration of 5.8 m / s ² was applied in the width direction for 30 minutes in a vibration test, and the amount of left / right displacement was measured.

  The vibration tester used was TR1000 manufactured by IMV Corporation.

Roll misalignment evaluation rank ○: Misalignment amount less than 2 mm Δ: Misalignment amount of 2 mm or more and less than 4 mm ×: Misalignment amount of 4 mm or more Transfer measurement method After storage at 40 ° C. and 80% temperature and humidity for about 10 days, unwind The occurrence m of transfer from the winding core was recorded.

Evaluation rank of transcription ○: Less than 10 m Δ: 10 m or more, less than 15 m ×: 15 m or more Measurement method of kuttsuki After being stored at 40 ° C. and 80% temperature and humidity for about 10 days, unwind and generate kuttsuki at 15 m The number was recorded.

Evaluation rank of Kutzki ○: Less than 2 △: 2 or more, less than 5 ×: 5 or more

  Sample No. 1 was prepared by measuring the diameter of the roll body and changing the height of the knurling based on the measured information when the optical film was used as a winding roll body on the winding shaft while giving knurling to both ends. It was confirmed that No. 101 exhibited excellent performance with no loosening, winding deviation, horse back, transfer, and cooking.

  Sample No. 1 was prepared by winding the optical film around the winding shaft with the knurling height applied to both ends constant to 5 μm. No. 102 causes loosening, winding deviation, horse back, transfer, and cooking. It was confirmed that the result was inferior to 101.

  Sample No. 2 was prepared by winding the optical film around the winding shaft with the knurling height applied to both ends constant to 4 μm. No. 103 is loosened, misaligned, transferred, and cooked. It was confirmed that the result was inferior to 101.

  Sample No. 1 was prepared by winding the optical film around the winding shaft with the knurling height applied to both ends constant at 3 μm. No. 104 has a horse back and a cook, and sample No. 104 of the present invention. It was confirmed that the result was inferior to 101.

Example 2
Sample No. 1 prepared in Example 1 was used. As shown in Table 3, all the gaps (air layers) of the optical film of the roll body were changed by changing the height of the knurling as shown in Table 3, and sample No. 101 was prepared. 201 to 206.

  The gap (air layer) indicates a value obtained by calculation in the same manner as in Example 1.

Evaluation The produced sample No. Table 4 shows the results obtained by measuring winding looseness, winding deviation, horse back, transfer, and cooking in the same manner as in Example 1 and evaluating according to the same evaluation rank as in Example 1.

  Sample No. produced with a gap of 0.7 μm to 1.5 μm. It was confirmed that Nos. 202 to 205 showed excellent results in winding looseness, winding deviation, horse back, transfer, and cooking.

  Sample No. produced with a gap of 0.5 μm was used. 201 was not a problem in practical use, but resulted in inferior winding, misalignment, and inferior horse back.

  Sample No. produced with a gap of 1.7 μm was used. Although 206 was not a problem in practical use, it resulted in poor transfer and cooking.

Example 3
Sample No. 1 prepared in Example 1 was used. When producing No. 101, as shown in Table 5, everything was produced by the same method except that the width, thickness and length of the optical film of the roll were changed. 301 to 315.

Evaluation The produced sample No. Regarding 301 to 315, winding looseness, winding deviation, horse back, transfer, and cooking were measured by the same method as in Example 1, and the results evaluated according to the same evaluation rank as in Example 1 are shown below.

  When an optical film having a width of 1000 mm to 2500 mm, a thickness of 15 μm to 50 μm, and a length of 5000 m to 8000 m is knurled at both ends, and the winding roll is used as a winding roll, the diameter of the roll is measured. Based on the measured information, the sample No. 5 was prepared while changing the height of the knurling. It was confirmed that 302 to 304, 307 to 309, and 312 to 314 showed excellent results in all of loose winding, winding deviation, horse back, transfer, and cooking.

  When the optical film having a width of 900 mm, a thickness of 30 μm, and a length of 7000 m is used as a winding roll body on the winding shaft while giving knurling to both ends, the diameter of the roll body is measured and the measured information is used. Sample No. produced while changing the height of the knurling. In the case of 301, loose winding, misalignment, horse back, transfer, and cooking were not problematic, but the results were inferior in productivity due to the narrow width.

  When the optical film having a width of 2600 mm, a thickness of 30 μm and a length of 7000 m is used as a winding roll body on the winding shaft while giving knurling to both ends, the diameter of the roll body is measured and the measured information is used. Sample No. produced while changing the height of the knurling. Although 305 is not a problem in practical use, Compared with 302 to 304, 307 to 309, and 312 to 314, the winding was loosened, and the horse back and the cook were inferior.

  When an optical film having a width of 1600 mm, a thickness of 10 μm, and a length of 7000 m is used as a winding roll body on the winding shaft while giving a knurling to both ends, the diameter of the roll body is measured, and based on the measured information Sample No. produced while changing the height of the knurling. Since No. 306 has a thickness of 10 μm, the height of the knurling is limited, and this is not a problem in practical use. Compared to 302 to 304, 307 to 309, and 312 to 314, the horse's back and transcription were inferior.

  When an optical film having a width of 1600 mm, a thickness of 60 μm, and a length of 7000 m is used as a winding roll body on the winding shaft while giving knurling to both ends, the diameter of the roll body is measured, and based on the measured information Sample No. produced while changing the height of the knurling. No. 310 shortened the winding length of one roll body, resulting in poor productivity.

  When an optical film having a width of 1600 mm, a thickness of 40 μm, and a length of 4000 m is used as a take-up roll body on a take-up shaft while giving a knurling to both ends, the diameter of the roll body is measured and based on the measured information. Sample No. produced while changing the height of the knurling. In the case of No. 311, loose winding, winding deviation, horse back, transfer, and cooking do not cause any problems, but because the length is as short as 4000 m, the number of windings is increased, resulting in poor productivity.

  When an optical film having a width of 1600 mm, a thickness of 40 μm, and a length of 9000 m is used as a winding roll body on a winding shaft while giving a knurling to both ends, the diameter of the roll body is measured and based on the measured information Sample No. produced while changing the height of the knurling. 315 is not a practical problem, but sample No. Compared with 302 to 304, 307 to 309, and 312 to 314, the winding was loosened, and the horse back and the cook were inferior.

DESCRIPTION OF SYMBOLS 1, 1 'Optical film manufacturing apparatus 101' Casting part 101'a Belt 101'b Die 103 'Stretching part 2 Melting extrusion part 202 Melting machine 3 Film shaping part 301 T die 4 Cooling take-up part 401 Cooling roll 402 Pressing Roll 403 Conveying roll 5, 105 ′ Knurling forming unit 501 Knurling forming device 501a Knurling forming roll 501b Receiving roll 501c Pressing means 501d Control device 6, 106 ′ Recovery unit 601 Winder 602 Entrained air amount control device 602a Touch roll 602b Pressing amount Control device 602'a Near roll 602'b Position control device 602'c Entrained air suction device 602'c1 Suction nozzle near roll 602'c2 Suction pipe 603 Shaft rotational speed measurement device 604 Linear encoder 605 Tension control device 605a Tension controller 605b Moving means 606 Film thickness measuring device 607 Winding shaft

Claims (5)

In the method for producing an optical film having an optical film as a take-up roll body while giving a knurling to both ends,
Winding of the optical film to the winding shaft measures the winding length and shaft rotation speed of the roll body,
A method for producing an optical film, comprising: controlling a gap between the optical films wound on the winding shaft while changing a height of the knurling based on the measured information.   The method for producing an optical film according to claim 1, wherein the gap is 0.7 μm to 1.5 μm.   The method for producing an optical film according to claim 1, wherein a touch roll is used when the optical film is wound on a winding shaft.   The method for producing an optical film according to claim 1, wherein when the optical film is wound on a winding shaft, a near roll and an accompanying air suction device are used.   5. The method for producing an optical film according to claim 1, wherein the optical film has a width of 1000 mm to 2500 mm, a thickness of 15 μm to 50 μm, and a length of 5000 m to 8000 m.

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