CN117460611A

CN117460611A - Method for manufacturing film roll and convex adjusting system used in manufacturing film roll

Info

Publication number: CN117460611A
Application number: CN202280040193.6A
Authority: CN
Inventors: 市川裕介; 小野俊哉; 桥本翔太; 田中博文; 中江叶月; 南条崇
Original assignee: Konica Minolta Inc
Current assignee: Konica Minolta Inc
Priority date: 2021-06-09
Filing date: 2022-03-14
Publication date: 2024-01-26
Also published as: TWI822053B; JPWO2022259668A1; KR20240006649A; WO2022259668A1; TW202313309A

Abstract

The invention provides a method for manufacturing a film roll suitable for manufacturing a wide film by processing, which can suppress the change of an orientation angle to be small without generating a roll failure, and a convex part adjusting system used for manufacturing the film roll. The method for producing a film roll by a solution or melt casting method is characterized by comprising at least: a film forming step, a protrusion adjusting step in the width direction of the film surface, a trimming step of both end portions of the film, and a winding step of the film trimmed by the trimming step, wherein the protrusion adjusting step is a step of adjusting the number, height, and position of the protrusions so that the protrusions continuously move in the length direction of the film surface by locally heating the film so that the number of protrusions is 1 to 10 per 1m in the width direction, and the height of the protrusions is 0.05 to 0.50 μm.

Description

Method for manufacturing film roll and convex adjusting system used in manufacturing film roll

Technical Field

The present invention relates to a method for producing a film roll and a convex portion adjustment system used for producing a film roll. More specifically, the present invention relates to a method for manufacturing a film roll suitable for manufacturing a wide film by processing the film, and a projection adjustment system used for manufacturing the film roll, which can suppress the change in orientation angle to a small level without causing a roll failure.

Background

In recent years, as the use of display devices has been expanding, there has been a demand for higher image quality and higher definition of display devices. Recently, 4K televisions (televisions having about 4 times the number of pixels of a full high definition television) have been commercially available.

In addition, in the future, a display device such as an 8K television is demanded which can achieve further high contrast.

Further, there is a strong demand for an increase in the size of the display device, and for films to be provided for this display, there is also a need to expand the width of the film roll to be supplied, and there is a strong demand for a film with less film damage due to roll failure and with less variation in the orientation angle in the width direction of the film.

Regarding a method for manufacturing a film roll, patent document 1 discloses the following technique: vibration cutting is performed after stretching and before trimming of the film (edge cutting is performed by moving the film base in the width direction at the base edge cutting portion in the pre-winding step).

However, it is not sufficient to suppress the variation of the orientation angle to a small level without occurrence of a roll failure.

On the other hand, patent document 2 discloses the following technique: in order to improve the above-described drawbacks, both end portions of a long film before stretching in a state of being vibrated (for example, a device for supporting the film to be conveyed is periodically moved) are trimmed, and the film is stretched, and further, the trimming is performed again, whereby a wound body of the stretched film (referred to as a "film roll") is produced which can suppress the drawbacks due to continuous thickness unevenness such as watchbands and lateral warpage, and which can suppress the change in orientation angle to be small.

However, the present inventors have made a large film roll using the above-described technique in response to the initial demand, and as a result, have found that there remains a disturbance in the change of the orientation angle according to the above-described technique, and there is room for improvement.

Prior art literature

Patent literature

Patent document 1: japanese patent laid-open No. 2002-255409

Patent document 2: japanese patent application laid-open No. 2015-123605

Disclosure of Invention

Problems to be solved by the invention

The present invention has been made in view of the above-described problems and situations, and an object of the present invention is to provide a method for producing a film roll suitable for production by wide film processing, which can suppress the fluctuation of orientation angle to be small without occurrence of roll failure, and a projection adjustment system used for producing the film roll.

Means for solving the problems

The present inventors studied the causes of the above problems and found that: in the production of the film roll, the number, height, and position of the protrusions in the width direction of the film surface are adjusted by locally heating the film, and the positions of the protrusions are adjusted so as to continuously move in the longitudinal direction of the film surface, whereby the above-described problems can be solved, and the present invention has been completed.

That is, the above-described problems of the present invention are solved by the following means.

1. A method for producing a film roll by a solution or melt casting method, comprising: a film forming step, a protrusion adjusting step in the width direction of the film surface, a trimming step of both end portions of the film, and a winding step of the film trimmed by the trimming step, wherein the protrusion adjusting step is a step of adjusting the number, height, and position of the protrusions so that the number of protrusions is in the range of 1 to 10 per 1m in the width direction and the height of the protrusions is in the range of 0.05 to 0.50 μm by applying local heating to the film, and the positions of the protrusions are adjusted so as to continuously move in the length direction of the film surface.

2. The method of producing a film roll according to claim 1, wherein in the trimming step, the film is not vibrated in the width direction of the film before both end portions of the film are trimmed.

3. The method for producing a film roll according to claim 1 or 2, wherein in the convex portion adjustment step, the position of the convex portion is adjusted to be aligned on a substantially straight line in the longitudinal direction of the film surface by locally heating the film, and an absolute value of an inclination angle of the substantially straight line with respect to the longitudinal direction of the film surface is in a range of 0.01 to 0.6 °.

4. The method for producing a film roll according to any one of items 1 to 3, wherein the local heating is performed by infrared heaters arranged in the width direction and the length direction of the film, heat source units of the infrared heaters are arranged at intervals of 10 to 100mm in the width direction of the film, the heat source units are arranged at positions different from the width positions in the length direction of the film, and the arranged heat source units E are arranged at the positions different from the width positions _A And E is _B The average inclination angle of the straight line connecting the two lines is in the range of 2 to 45 DEG with respect to the longitudinal direction.

5. The method for producing a film roll according to any one of items 1 to 4, wherein an average value B of heat A at a central portion and heat B at an end portion of the infrared heater satisfies the following formula (1),

formula (1): 0.2 < (B/A) < 0.6.

6. The method of producing a film roll according to any one of claim 1 to 5, wherein after the finishing step, no knurling is performed on the film.

7. The method for producing a film roll according to any one of items 1 to 6, characterized in that a maximum height difference (P-V) of a length average film thickness at each width position of film thickness values measured in the order of the following steps 1 to 3 in a direction inclined with respect to the width direction of the film is in a range of 0.02 to 0.40 μm,

Step 1:

after the film thickness was measured at an arbitrary position at the end of the film, the film thickness was measured at a position shifted 10mm in the width direction and 30mm in the length direction from the arbitrary position at each measurement, the width position, the length position, and the film thickness value were recorded, and repeated until the other film was reached at the end,

step 2:

after the completion of the step 1, the same measurement as in the step 1 was performed until the total distance of the moving positions in the longitudinal direction reached 1000m,

step 3:

from the large amount of film thickness data obtained from the above steps 1 and 2, the film thickness values at the same width position are subjected to an averaging process, the length average film thickness value at each width position is obtained, and the height difference (P-V) between the maximum value and the minimum value is calculated therefrom.

8. A protrusion adjusting system for manufacturing a film roll, which is used in manufacturing a film roll having a protrusion adjusting step of adjusting the number, height and position of protrusions in the width direction of a film surface, is characterized by comprising: a film thickness acquisition means for acquiring a film thickness profile of the film during or after the completion of the projection adjustment process; a determination means for determining, based on the data of the film thickness profile, whether or not the number of the protrusions in the width direction is within a range of 1 to 10 ideal values per 1m and whether or not the height of the protrusions in the width direction is within a range of 0.05 to 0.50 [ mu ] m; and means for heating the film locally by using an infrared heater so that the number of the convex portions and the height of the convex portions are both within a range of the ideal value when the number of the convex portions and the height of the convex portions are both outside the range of the ideal value in the determination means.

Effects of the invention

The above-described means of the present invention can provide a method for producing a film roll suitable for production by wide film processing, which can suppress the change in orientation angle to a small level without occurrence of a roll failure, and a convex portion adjustment system used for producing the film roll.

The mechanism of appearance or action of the effect of the present invention is not clear, and is presumed as follows.

The present inventors have examined a technique of improving film performance by vibrating before trimming before stretching and after stretching the film disclosed in patent document 1 and patent document 2.

Patent document 1 discloses that the orientation angle is disturbed by performing a vibration operation after stretching the film, that is, in a state where the orientation angle is uniform.

In patent document 2, the disturbance of the orientation angle is suppressed by performing the vibration operation before stretching the film, that is, before the orientation angle is aligned, and even then the disturbance of the orientation angle remains.

Among them, the vibration operation is a technique of changing the position of the irregularities on the macroscopic film surface in the width direction, for example, preventing the overlapping of the convex portions when the roll is formed, and the film using this technique is problematic when being assembled into a display device because air is unevenly taken in the film roll at the time of winding, and therefore the roll is deformed, for example, deformed in a chain shape, by the air gradually coming off as time passes.

Accordingly, the present inventors have found that the amount of air taken in the film roll can be controlled to a high degree by controlling the number of protrusions and the height of the protrusions in the width direction of the film surface within a certain range and adjusting the positions of the protrusions so as to continuously move in the longitudinal direction of the film surface, thereby preventing the protrusions of the film from overlapping at the time of winding.

Drawings

Fig. 1 is a graph showing a relationship between a convex portion and a film thickness profile in the width direction.

Fig. 2 is a flowchart showing a flow of the manufacturing process of the present invention.

Fig. 3 is a schematic view of an apparatus for producing a film by a solution casting film formation method.

Fig. 4A is a schematic view showing that the convex portions are arranged and adjusted continuously in a straight line in the longitudinal direction with respect to the convex portions.

Fig. 4B is a schematic view showing that the convex portions are arranged and adjusted continuously in a straight line in the longitudinal direction with respect to the convex portions.

Fig. 4C is a schematic view showing the arrangement and adjustment of the convex portions along the curved line in the longitudinal direction.

Fig. 5 is a diagram showing a relationship with the drawing of the position of the convex portion in an approximate straight line.

Fig. 6A is a view showing the infrared heaters arranged in 1 row in the longitudinal direction of the film.

Fig. 6B is a view of infrared heaters arranged in 2 rows in the longitudinal direction of the film.

Fig. 6C is a view showing the infrared heaters arranged in 5 rows in the longitudinal direction of the film.

Fig. 7A is a view showing an average inclination of a straight line formed between each heat source unit and the longitudinal direction.

Fig. 7B is a view showing an average inclination of a straight line formed between each heat source unit and the longitudinal direction.

Fig. 8 is a cross-sectional view of a surface perpendicular to a surface of the film of the tenter stretching device from the upper side.

Fig. 9 is a schematic view of the nozzle and heater arrangement portion when the 3 regions in the tenter stretching device are viewed from the front.

Fig. 10 is a side view of 3 zones within the tenter device.

Fig. 11 is a cross-sectional view of a surface perpendicular to a surface of the film of the tenter stretching device from the upper side.

Fig. 12 is a schematic diagram showing a step of winding a film and a cross section of the film roll of the present invention after winding.

Fig. 13 is a schematic configuration diagram of an apparatus for producing an optical film by a melt-casting film-forming method.

Fig. 14 is an example of a heat map for confirming continuity.

Detailed Description

The method for producing a film roll according to the present invention is a method for producing a film roll by a solution or melt casting method, comprising: a film forming step, a protrusion adjusting step in the width direction of the film surface, a trimming step of both end portions of the film, and a winding step of the film trimmed by the trimming step, wherein the protrusion adjusting step is a step of adjusting the number, height, and position of the protrusions so that the number of protrusions is in the range of 1 to 10 per 1m in the width direction and the height of the protrusions is in the range of 0.05 to 0.50 μm by applying local heating to the film, and the positions of the protrusions are adjusted so as to continuously move in the length direction of the film surface.

This feature is common to or corresponding to the following embodiments (configurations).

In the present invention, from the viewpoint of the effect of the present invention, it is preferable that the film is not vibrated in the width direction of the film before the both end portions of the film are trimmed in the trimming step.

In the convex portion adjustment step, the position of the convex portion is preferably adjusted to be aligned in a substantially straight line in the longitudinal direction of the film surface by locally heating the film, and the absolute value of the inclination angle of the substantially straight line with respect to the longitudinal direction of the film surface is preferably in the range of 0.01 to 0.6 ° from the viewpoint that the convex portions of the film do not overlap each other in the winding step and an unnecessary air layer is not generated.

From film thickness controlIn terms of the performance and stability and in terms of making the respective heat source units at appropriate intervals, it is preferable to perform the local heating by using infrared heaters arranged in the width direction and the length direction of the film, arrange the heat source units of the infrared heaters at intervals of 10 to 100mm in the width direction of the film, arrange the heat source units at positions different from the width positions in the length direction of the film, and arrange the heat source units E _A And E is _B The average inclination angle of the straight line connecting the two lines is in the range of 2 to 45 DEG with respect to the longitudinal direction.

From the viewpoint of exhibiting the effect of the present invention, it is preferable that the average value B of the heat quantity a of the central portion and the heat quantity B of the end portions of the infrared heater in the infrared heater satisfies the above formula (1).

From the viewpoint of suppressing excessive air intake, it is preferable that no knurling process is performed on the film after the finishing process.

From the viewpoint of the effect of the present invention, it is preferable that the maximum height difference (P-V) of the length average film thickness at each width position of the film thickness values measured in the order of the steps 1 to 3 in the direction inclined with respect to the width direction of the film is in the range of 0.02 to 0.40 μm.

The present invention provides a convex portion adjustment system used in manufacturing a film roll, the convex portion adjustment system being used in manufacturing a film roll having a convex portion adjustment step of adjusting the number, height and position of convex portions in the width direction of a film surface, the convex portion adjustment system comprising: a film thickness acquisition means for acquiring a film thickness profile of the film during or after the completion of the projection adjustment process; a determination means for determining, based on the data of the film thickness profile, whether or not the number of the protrusions in the width direction is within a range of 1 to 10 ideal values per 1m and whether or not the height of the protrusions in the width direction is within a range of 0.05 to 0.50 [ mu ] m; and means for heating the film locally by using an infrared heater so that the number of the convex portions and the height of the convex portions are both within a range of the ideal value when the number of the convex portions and the height of the convex portions are both outside the range of the ideal value in the determination means.

Thus, the effect of the present invention is exhibited, and the problem can be solved.

The present invention and its constituent elements, and modes for carrying out the present invention will be described in detail below. In the present application, "to" is used in the meaning of the lower limit value and the upper limit value inclusive of the numerical values described before and after the "to" are used.

[ outline of the method for producing film roll of the present invention ]

The method for producing a film roll according to the present invention is a method for producing a film roll by a solution or melt casting method, comprising: a film forming step, a protrusion adjusting step in the width direction of the film surface, a trimming step of both end portions of the film, and a winding step of the film trimmed by the trimming step, wherein the protrusion adjusting step is a step of adjusting the number, height, and position of the protrusions so that the number of protrusions is 1 to 10 per 1m in the width direction and the height of the protrusions is 0.05 to 0.50 μm by applying local heating to the film, and the positions of the protrusions are adjusted so as to continuously move in the length direction of the film surface.

In the present invention, by adopting the above means, an air layer (air layer) can be properly taken in a film roll in the film winding process, and uneven take-in of air is suppressed, so that minute contact is properly generated on the entire surface of the contact surfaces of the films facing each other, and a roll defect such as a chain is not caused, and an effect of preventing a roll deviation during conveyance is obtained.

The film formation of the film according to the present invention is a solution casting film formation method or a melt casting film formation method, and in particular, a solution casting film formation method is more preferable in order to obtain a uniform surface.

First, the meaning of the main terms according to the present invention will be described below.

Definition of the term relating to the convex portion

In the present invention, the "convex portion" refers to a portion of the height of the concave-convex shape of the thickness of the optical film measured and observed by film thickness measurement, which is higher than the average film thickness, that is, is thicker than the average film thickness.

Details are as follows.

In measurement and evaluation of the state of the convex portion, after measurement of the film thickness at an arbitrary position at the end portion of the film, the film thickness at a position shifted by 10mm in the width direction and 30mm in the length direction from the arbitrary position is measured at each measurement, and repeated until the end portion of the other film is subjected to a gaussian filter treatment to remove noise, thereby obtaining a film thickness profile in the width direction, and the state of the convex portion is measured and evaluated based on the profile (for the number, height, and position of the final convex portion, measurement of the end portion of the film after the cutting step described later).

In the present invention, the term "end portion of the film" means a region portion within 15 to 30mm from the end in the width direction of the film (roll), and the term "film roll" means a film wound in a roll shape.

(number of protruding portions)

The average film thickness was determined by taking the average value of the measured values of each film thickness in the width direction obtained by the above-described operation, and the portion where the film thickness profile in the width direction was 50mm or more in the width direction was set as the convex portion and the number of the portion was set as the number of the convex portions as shown in fig. 1.

If the number of the convex portions is too large, the individual hills become sharp, and if the number of the convex portions is too small, the film is deformed, and if the number of the convex portions is too small, stress is too concentrated at the time of film winding, and distortion and the like occur.

Therefore, the effect of the present invention can be expected by setting the number of the protruding portions to be in the range of 1 to 10 per 1m in the width direction.

(position and height of the protruding portion)

In each of the convex portions specified by the above method, the position at which the maximum value is taken is defined as the position of the convex portion, and the value obtained by subtracting the average film thickness in the width direction from the maximum value of the convex portion is defined as the height h of each convex portion.

If the height of the convex portion is too high, a chain shape is generated at the foot portion after the film roll is left for a long time, and if the height of the convex portion is too low, the film thickness dispersion effect disappears.

Therefore, the effect of the present invention can be expected by setting the height of the protruding portion to be in the range of 0.05 to 0.50 μm.

The position of the convex portions is adjusted so as to continuously move in the longitudinal direction of the film surface so that the convex portions do not overlap each other at the time of film winding, and the effect of the function of adjusting the number and height of the convex portions can be further improved.

The film thickness was measured using an in-line retardation/film thickness measuring device RE-200L2T-Rth+ film thickness (manufactured by Otsuka electronics Co., ltd.).

1. Method for producing film roll by solution casting film-forming method

Fig. 2 is a flowchart showing a flow of a manufacturing process of the film roll manufacturing method of the present invention.

The following solution casting film forming method will be described with reference to fig. 2 and 3.

The method for producing a film roll by a solution casting film formation method of the present invention comprises a film formation step (S1), a protrusion adjustment step (S2), a trimming step (S3), and a winding step (S4).

(1.1) film Forming step (S1)

(1.1.1) preparation of cement

In the film forming step (S1), at least the resin and the solvent are stirred in the stirring tank 1a of the stirring device 1 to prepare a dope to be cast on the support 3 (endless belt).

Hereinafter, as an embodiment of the present invention, a case where a cement is prepared using a cycloolefin resin (hereinafter, also referred to as "COP") as a thermoplastic resin will be described as an example, but the present invention is not limited thereto.

In a solvent mainly containing a good solvent for cycloolefin resin (COP), a cement is prepared by stirring the COP in a dissolution tank and optionally stirring other compounds, or a cement as a main dissolution solution is prepared by mixing other compound solutions in the COP solution.

(concentration of resin)

Details of the type of resin and the like will be described later.

When the concentration of the cycloolefin resin (COP) in the dope is high, the drying load after casting of the support can be reduced, which is preferable.

However, if the COP concentration is too high, the load during filtration increases and the accuracy deteriorates.

The concentration of both is preferably in the range of 10 to 35% by mass, more preferably in the range of 15 to 30% by mass.

(solvent)

As the solvent, a mixed solvent of a good solvent and a poor solvent is used.

The solvent used in the cement may be used alone or in combination of two or more, and in terms of productivity, it is preferable to use a good solvent and a poor solvent for the cycloolefin resin (COP) in combination, and in terms of solubility of COP, it is preferable that the good solvent is large.

The preferable range of the mixing ratio of the good solvent to the poor solvent is 70 to 98 mass% and the poor solvent is 2 to 30 mass%.

In the present invention, the good solvent and the poor solvent are defined as solvents in which the cycloolefin resin (COP) used alone is dissolved, and solvents in which the cycloolefin resin (COP) is swollen or not dissolved alone are defined as poor solvents.

Therefore, the good solvent and the poor solvent are changed according to the average substitution degree of COP.

The good solvent used in the present invention is not particularly limited, and examples thereof include organic halides such as methylene chloride, dioxolanes, acetone, methyl acetate, methyl acetoacetate, and the like.

Particularly preferably, methylene chloride or methyl acetate is exemplified.

The poor solvent used in the present invention is not particularly limited, and for example, methanol, ethanol, n-butanol, cyclohexane, cyclohexanone and the like are preferably used.

The cement preferably contains 0.01 to 2 mass% of water.

In addition, the solvent used for dissolving the cycloolefin resin (COP) is recovered by drying the solvent removed from the film in the film forming step, and is reused.

The recovered solvent may contain a small amount of an additive added to COP, for example, a plasticizer, an ultraviolet absorber, a polymer, a monomer component, and the like, and if necessary, the recovered solvent may be preferably reused, and may be purified for reuse.

As the above-described method for dissolving COP in the preparation of cement, a general method can be used.

Specifically, a method performed under normal pressure, a method performed at a boiling point of the main solvent or less, and a method performed under pressure at a boiling point of the main solvent or more are preferable, and if heating and pressurizing are combined, heating to a boiling point of the normal pressure or more is possible.

The method of stirring and dissolving the solvent at a temperature not lower than the boiling point of the solvent under normal pressure and within a range where the solvent does not boil under pressure is preferable because it prevents the formation of gels or lumps of undissolved substances called pimples.

In addition, the following method is also preferably employed: cycloolefin resin (COP) is mixed with a poor solvent, and after wetting or swelling, the poor solvent is further added and dissolved.

The pressurization may be performed by a method of pressurizing an inert gas such as nitrogen or a method of increasing the vapor pressure of the solvent by heating.

The heating is preferably performed from the outside, for example, jacket-type heating is preferable because temperature control is easy.

From the viewpoint of solubility of cycloolefin resin (COP), it is preferable that the heating temperature of the solvent to be added is high, and if the heating temperature is too high, the required pressure becomes large, and productivity becomes poor.

The heating temperature is preferably in the range of 30 to 120 ℃, more preferably in the range of 60 to 110 ℃, and even more preferably in the range of 70 to 105 ℃.

In addition, the pressure is adjusted so that the solvent does not boil at the set temperature.

Alternatively, a cooling dissolution method is also preferably employed, whereby the cycloolefin resin (COP) can be dissolved in a solvent such as methyl acetate.

(filtration)

Next, the cycloolefin resin (COP) solution (cement in solution or after dissolution) is preferably filtered using an appropriate filter material such as filter paper.

As the filter material, it is preferable that the absolute filtration accuracy is small in order to remove insoluble matters or the like, but if the absolute filtration accuracy is too small, clogging of the filter material is likely to occur.

Therefore, a filter having an absolute filtration accuracy of 0.008mm or less is preferable, a filter having a thickness of 0.001 to 0.008mm is more preferable, and a filter having a thickness of 0.003 to 0.006mm is still more preferable.

The material of the filter medium is not particularly limited, and a usual filter medium, a filter medium made of plastic such as polypropylene or teflon (registered trademark), a filter medium made of metal such as stainless steel, or the like can be used, and it is preferable that the filter medium has no fiber fall off.

Preferably, impurities contained in the cycloolefin resin (COP) as a raw material, particularly, bright-spot foreign matter is removed and reduced by filtration.

The bright spot foreign matter means a spot (foreign matter) which is observed by light leakage from the opposite side when light is irradiated from one polarizer side and the other polarizer side is observed by arranging 2 polarizers in a crossed nicols state and placing a film or the like therebetween, and the number of bright spots with a diameter of 0.01mm or more is preferably 200 per cm ² The following is given.

More preferably 100/cm ² Hereinafter, more preferably 50/m ² Hereinafter, more preferably 0 to 10 pieces/cm ² The following is given.

In addition, the number of bright spots of 0.01mm or less is preferably small.

The filtering of the dope can be carried out by a usual method, and a method of filtering while heating at a temperature within a range where the boiling point of the solvent is not lower than the normal pressure and the solvent is not boiled under pressure is preferable because the increase in the difference between the filtering pressures (referred to as the differential pressure) before and after the filtering is small.

The temperature is preferably in the range of 30 to 120 ℃, more preferably in the range of 45 to 70 ℃, and even more preferably in the range of 45 to 55 ℃.

Preferably, the filtration pressure is small.

Specifically, the pressure is preferably 1.6MPa or less, more preferably 1.2MPa or less, and still more preferably 1.0MPa or less.

(1.1.2) casting of the cement

In the case of the dope cast on the support 3, the dope is fed to the casting die 2 by a pressure type quantitative gear pump or the like by a pipe, and the dope is cast from the casting die 2 to a casting position on the support 3 constituted by a rotary-driven stainless steel endless belt which is infinitely conveyed.

At this time, the inclination angle of the casting die 2, that is, the discharge direction of the dope from the casting die 2 to the support 3 may be appropriately set so that the angle with respect to the normal line of the face of the support 3 (face on which the dope is cast) is in the range of 0 to 90 °.

At this time, the support 3 is heated to evaporate the solvent until the casting film 5 can be peeled off from the support 3 by using a peeling roller (also referred to as "roller") 4.

The casting film 5 is cured to be a releasable casting film, which is simply referred to as a "film".

(solvent Evaporation method)

The evaporation is preferably performed in an atmosphere at a temperature in the range of 5 to 75 ℃.

When evaporating the solvent, there are a method of spraying warm air onto the upper surface of the casting film and/or a method of transferring heat by liquid from the back surface of the support 3, a method of transferring heat from the front surface to the back surface by radiant heat, and the like, and a method of transferring heat from the front surface to the back surface by radiant heat is preferable because drying efficiency is good.

In addition, a method of combining them is also preferably used.

(width of casting)

From the viewpoint of productivity, the width of casting (casting) is preferably 1.3m or more.

More preferably in the range of 1.3 to 4.0 m.

If the width of casting (casting) is not more than 4.0m, streaks are not generated in the manufacturing process, and stability in the subsequent handling process is increased.

From the viewpoints of portability and productivity, the thickness is more preferably in the range of 1.3 to 3.0 m.

(support)

The support 3 in casting of the dope is preferably a support having a mirror finished surface and is held by a pair of rolls 3a and 3b and a plurality of rolls located therebetween.

A driving device for applying tension to the support body 3 is provided to one or both of the rollers 3a and 3b, and thereby the support body 3 is used in a state of being tensioned by applying tension.

As the support 3, a stainless steel belt or a drum whose surface is subjected to plating finishing with a casting is preferably used.

The surface temperature of the support 3 during casting of the dope is preferably in the range of-50 ℃ to the boiling point of the solvent, since the drying rate of the casting film can be accelerated when the temperature is high.

The support temperature is preferably in the range of 0 to 55 ℃, more preferably 22 to 50 ℃.

The method of controlling the temperature of the support 3 is not particularly limited, and there are a method of injecting warm air or cool air and a method of bringing warm water into contact with the back side of the support.

When warm water is used, heat transfer is efficiently performed, and therefore, it is preferable to shorten the time until the temperature of the support becomes constant.

When warm air is used, air having a temperature higher than the target temperature may be used.

Film thickness control means in film formation step

In the method for producing a film roll of the present invention, from the viewpoint of exhibiting the effect of the present invention, it is preferable that the maximum height difference (P-V) of the length average film thickness at each width position of the film thickness values measured in the order of the following steps 1 to 3 in the direction inclined with respect to the film width direction is in the range of 0.02 to 0.40 μm.

Step 1:

after the film thickness was measured at an arbitrary position at the end of the film, the film thickness was measured at a position shifted 10mm in the width direction and 30mm in the length direction from the arbitrary position at each measurement, and the width position, the length position, and the film thickness value were recorded and repeated until the end of the other film.

Step 2:

after the completion of the step 1, the same measurement as in the step 1 was performed until the total distance of the moving positions in the longitudinal direction reached 1000m.

Step 3:

from the plurality of film thickness data obtained in the steps 1 and 2, the film thickness values at the same width position are subjected to an averaging process, and the length average film thickness value at each width position is obtained. From which the difference in height (P-V) between the maximum value and the minimum value is calculated.

In order to adjust the maximum height difference (P-V) of the length average film thickness at each width position of the film thickness values measured in the order of steps 1 to 3 below in the direction inclined with respect to the width direction of the film according to the present invention to be a desired value, for example, the following three film thickness control means are used in the film forming step.

In the convex portion adjustment step, the maximum height difference (P-V) of the length-average film thickness may be adjusted to a desired value, and this will be described later in the convex portion adjustment step.

In addition, they may be combined.

(film thickness control means 1: pump pulse pitch control)

The film thickness is controlled by controlling the pitch of the pump pulses.

It is known that a gear pump with high accuracy is used for the cement feed (extrusion of resin in the case of melting) in a pipe reaching a casting die, and the gear pump can control the pitch of pump pulsation by controlling the rotation speed of the pump according to the gear ratio thereof, so that the pulsation during the feed of the pump has a large influence on the average maximum height difference (P-V) of the film thickness in the longitudinal direction and the average film thickness in the length.

Here, the liquid feeding capability of the pump will be described in addition.

In casting of cement, if the length of the piping from the pump to the casting die is not too short, pulsation is not increased by the rotation speed of the pump, and if it is not too long, pressure loss is not excessively increased, and it is possible to prevent the liquid feeding capability of the pump from being lowered beyond the lower limit.

Further, if the rotation speed of the pump is not too low, the liquid feeding capability can be prevented from being lowered, and if it is not too high, the pressure loss is not excessively increased, and the liquid feeding capability can be prevented from being lowered.

From the above point of view, it is preferable to adjust the gear ratio of a gear pump used for the cement liquid feed (extrusion of the resin in the case of melting) so that the rotation speed of the pump is in the range of 10 to 50rpm, in the range of 50 to 100m in length of a pipe from the pump to the casting die.

(film thickness control means 2: film thickness control by hot bolts)

The initial discharge film thickness was controlled by using a hot screw of the casting die.

In order to improve the uniformity of film thickness in casting of a dope, a method of controlling a slit gap of a lip portion of a casting die in both a solution casting film-forming method and a melt casting film-forming method is exemplified by those skilled in the art.

For example, the following method is adopted: when extruding a cement (including a melt) having a high viscosity, the width of the slit gap is varied, and a plurality of hot bolts are provided in a width to control the slit gap so as to prevent the variation.

However, this method has a problem in that there is a physical setup limit of the number of hot bolts.

In addition, in order to suppress the pressure fluctuation in the width that causes the variation in the width of the slit gap, there is a method of changing the internal structure of the casting die in the width, but the casting die must be replaced for each production item, which has a problem of taking time and cost.

A mechanism for adjusting the width of a slit for discharging cement (extrusion of resin in the case of melting) is provided in the casting die.

Here, a method of controlling the initial discharge film thickness of a cast film by adjusting the gap of the width of a slit for discharging a dope by using a hot screw of a casting die will be described in addition.

In casting of the dope, if the gap of the width of the slit from which the dope is discharged is not too small, it is technically easy to prepare the dope without taking time by using a hot bolt of a casting die.

In addition, if the gap of the width of the slit for discharging the dope is too large, the initial discharge film thickness of the casting film cannot be flattened.

From the above point of view, it is preferable to control the initial discharge film thickness of the cast film by adjusting the gap of the width of the slit for discharging the dope to a range of 1.0 to 5.0% of the film thickness deviation immediately after the discharge with respect to the whole cast film by using a hot screw of the casting die in the casting step described later.

Here, the portion of the casting die slot from which the dope comes out is called a die lip, and a casting die in which the slot shape of the die lip portion can be adjusted and the film thickness can be easily made uniform is preferable.

Among the casting dies, there are a coat hanger type die, a T type die, etc., and all of them are preferably used.

In the present invention, the casting film means a paste film which is cast from the die lip portion.

In order to increase the film forming speed of the film according to the present invention, two or more casting dies as described above may be provided on the support, and the dope may be divided and laminated.

Alternatively, a co-casting method in which a plurality of dope layers are simultaneously cast is also preferably employed to obtain a film roll having a laminated structure.

The slit is narrowed by pressing in with a manual rotary hot bolt, and the film thickness is thinned, or conversely opened to be thicker.

The method of pressing by heat is also common by applying a voltage to the hot bolt, but is generally used in combination.

In addition, a push-pull method can be adopted.

However, the pitch of the bolts may not be narrowed in the mechanism of the casting die, and in the case of a dope having a high viscosity (including melting), a die lip may be subjected to a large pressure load at the time of discharging the casting die, and a variation in film thickness in the width direction may occur, such as a rapid decrease in load after discharging and a large film thickness (balance effect).

Therefore, depending on the structure inside the casting die, a design is necessary in which a load is not excessively applied to the die lip of the casting die.

(film thickness control means 3: film thickness control by Hot air)

The hot air is sprayed to the casting film, and the heat is used to planarize the protrusion portion, thereby controlling the film thickness.

On the tape of the dope, the wind may be sprayed in a state where the surface layer on the reverse side of the casting film is formed, or the hot wind may be sprayed immediately after the casting film is peeled from the tape.

At this time, since the interior of the casting film is soft due to the solvent contained therein, the protrusion is flattened, and thus the thickness of the film is controlled by adjusting the temperature, the wind speed, or the wind volume of the drying wind and adjusting the amount of the residual solvent by measuring the non-uniformity in the width direction of the casting film on line.

Here, the temperature of the drying air, the air speed or the air volume, and the residual solvent amount will be described in addition.

The film thickness can be appropriately controlled without excessively lowering the temperature of the drying air, excessively lowering the air speed, or excessively lowering the air volume.

Further, the film thickness is not locally uncontrollable as long as the temperature is not excessively high, the wind speed is excessively high, or the wind quantity is excessively large.

If the amount of the residual solvent is not too small, the film is not soft and cannot be flattened in a state closer to the film than in a state such as a casting film.

If the amount is not too large, no deviation in film thickness will occur during planarization.

By this, the amount of the residual solvent is appropriately set, and thus the planarization 3 can be performed in a state where the surface layer is formed as a thin film.

From the above point of view, the temperature of the drying air is preferably in the range of 10 to 80 ℃, and the wind speed is preferably in the range of 5 to 40 m/sec.

The amount of the residual solvent is preferably 150 to 550% by mass.

Further, if the above-described operation is performed in a state where the surface layer on the reverse side of the casting film is not yet formed, streaks are formed, and the inside is not preferable.

On the tape of the casting time of the dope, the non-uniformity in the width direction of the film thickness deviation of the casting film is measured on line, and when hot air is sprayed in a manner of reducing the non-uniformity, the film thickness is controlled by adjusting the temperature.

(1.1.3) stripping of film

The solvent is evaporated on the support 3 until the cast film 5 becomes a peelable film strength, and after drying, solidifying or cooling, solidifying, the film is peeled off from the support 3 with the peeling roller 4 in a state where the film is self-supporting before the film is wound around the support 3 for one week.

The casting film 5 after being cured to be peelable is simply referred to as a "film".

In this case, from the viewpoint of surface quality, moisture permeability, and peelability, the film is preferably peeled from the support within a range of 30 to 600 seconds.

The position at which the film is peeled from the support is referred to as a peeling point, and a peeling-assisting roller is referred to as a peeling roller.

The temperature at the peeling position on the support is preferably set in the range of-50 to 40 ℃, more preferably in the range of 10 to 40 ℃, and most preferably in the range of 15 to 30 ℃.

(residual solvent amount at film peeling)

The amount of the residual solvent in the film on the support 3 at the time of peeling is appropriately adjusted by the strength of the drying condition, the length of the support 3, and the like.

Also depending on the thickness of the film, if the amount of the residual solvent at the peeling point is too large, the film may be too soft, become difficult to peel, sometimes deteriorate planarity, or may easily cause lateral warpage, surface irregularities, longitudinal streaks due to peeling tension.

Conversely, if the amount of the residual solvent is too small, a part of the film may be peeled off in the middle.

In order to achieve good flatness of the film, the amount of the residual solvent is preferably in the range of 10 to 50 mass% from the viewpoint of both economical speed and quality.

As a method for increasing the film forming speed (peeling is performed when the amount of residual solvent is as large as possible, and thus the film forming speed can be increased), there is a gel casting method (gel casting) in which peeling is performed even when the amount of residual solvent is large.

As this method, there is a method of adding a poor solvent for cycloolefin resin (COP) to a dope and gelling a casting film after casting the dope; and a method in which the support is cooled to gel the casting film and the casting film is peeled off in a state where a large amount of residual solvent is contained.

In addition, there is a method of adding a metal salt to the cement.

As described above, the cast film is gelled on the support, and the film is strengthened, so that peeling is advanced, and the film forming speed can be increased.

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

Residual solvent amount (% by mass) = { (M-N)/N } ×100

M is the mass of a sample taken at any time during or after the production of the casting film or the film, and N is the mass of a sample having a mass M after heating at 115 ℃ for 1 hour.

(peel tension)

The peeling tension when peeling the support and the film is preferably 300N/m or less.

More preferably, the tension is in the range of 196 to 245N/m, and when wrinkles are easily generated during peeling, the peeling is preferably performed with a tension of 190N/m or less.

(1.1.4) shrinkage in film plane

The film peeled from the support is stretched by applying tension in the transport direction (Machine Di rect ion, hereinafter also referred to as "MD direction") to shrink the film.

In this case, the film shrinks in the width direction (Traverse Di rect ion, hereinafter also referred to as "TD direction") orthogonal to the MD direction within the film surface.

By the above-described operation, entanglement between polymer molecules (matrix molecules) in the film thickness direction is promoted, and even when the film is bonded to the adhesive via the polarizer layer at the time of producing the polarizing plate, the adhesive is likely to penetrate into the film via entangled portions (crosslinked portions) between the matrix molecules.

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

That is, good adhesion between the film and the polarizer layer can be ensured.

In addition to the above, as a method for shrinking the film, for example, there is a method of subjecting the film to a high temperature treatment in a state where the width is not maintained, to increase the density of the film; and a method of drastically reducing the residual solvent amount of the film.

(shrinkage of film)

In the present invention, the shrinkage is defined by the following formula.

The formula: shrinkage [% ] = width of film after shrinkage [ mm ]/width of film at start of shrinkage [ mm ] ×100

Among them, if the shrinkage of the film is too small, the effect of promoting entanglement between molecules of the matrix becomes insufficient, and if it is too large, there is a concern that the production efficiency of the film is lowered.

Therefore, the shrinkage of the film is preferably in the range of 1 to 40%, more preferably in the range of 5 to 20%.

(method for measuring shrinkage and method for calculating shrinkage)

In the present invention, LS-9000 manufactured by KEYENCE, inc. was used to measure the width of the film.

The shrinkage of the film according to the present invention is obtained by using the above-described measuring device to measure the average value of the values of 5 minutes (300 seconds) per 1 second for the film width as the film width, and substituting the average value into the above formula, and is not necessarily limited to the above-described method, and for example, a value in which the film width is read from a scale may be used as the film width, and substituted into the above formula.

(1.1.5) drying of film

The film is heated on the support by the drying device 6 to evaporate the solvent, thereby further drying.

The temperature of the support may be the same throughout, or may vary from location to location.

In general, a roll drying method (a method of drying a film by alternately passing the film through a plurality of rolls arranged up and down) and a tenter method of drying the film while conveying the film are used for drying the film.

In the tenter method, when a tenter stretching device is used, it is preferable to use a device in which the gripping length (the distance from the start of gripping to the end of gripping) of the film can be independently controlled from left to right by left and right gripping means using the tenter stretching device.

In the drying apparatus 6 shown in fig. 3, the film is conveyed by a plurality of conveying rollers arranged in a zigzag form in a side view, and the film is dried therebetween.

The drying method in the drying device 6 is not particularly limited, and a method of drying the film with hot air, infrared rays, a heating roller, microwaves, or the like is generally used, and a method of drying the film with hot air is preferable in terms of simplicity.

In addition, a method of combining them is also preferable.

The above-described operations may be performed as needed.

If the film thickness is thin, the drying is fast, but too rapid drying tends to impair the planarity of the finished film.

(residual solvent amount at film drying)

In the case of drying at a high temperature, it is necessary to consider the amount of the residual solvent, and by keeping the amount of the residual solvent not too large, the occurrence of failure due to foaming of the solvent can be prevented.

The amount of the residual solvent is preferably about 30% by mass or less, and the whole drying is preferably carried out at a temperature of about 30 to 250 ℃.

It is particularly preferred to dry it in the range from 35 to 200℃and the drying temperature is preferably increased stepwise.

The amount of the residual solvent in the film on the support 3 at the time of film peeling is appropriately adjusted by the strength of the drying condition, the length of the support 3, and the like, and the film thickness, the resin, and the like are greatly affected by the shrinkage in the film surface, the amount of the residual solvent in the drying of the film, and therefore, there is a range overlapping the preferable range of the amount of the residual solvent.

(1.2) protruding portion adjustment step (S2)

(1.2.1) outline of the procedure for adjusting the convex portion

The protrusion adjustment step in the width direction of the film surface according to the manufacturing method of the present invention is a step of adjusting the number, height and position of the protrusions, and is characterized in that the number of the protrusions is 1 to 10 per 1m in the width direction by applying local heating to the film, and the height of the protrusions is 0.05 to 0.50 μm, and the position of the protrusions is adjusted so as to continuously move in the longitudinal direction of the film surface.

In the present invention, the film is locally heated as a means for adjusting the protruding portion.

The local heating means includes an Infrared (IR) heater, hot air, and the like, and the heat treatment is not particularly limited, and may be performed by other methods.

The hot air type has an advantage of having sufficient film thickness adjusting ability regardless of the material.

On the other hand, although the continuous movement control of the valleys is slightly difficult, the convex portions can be continuously moved by appropriately controlling the temperature, the air volume, the nozzle pressure, and the like.

In the present invention, from the viewpoints of film thickness controllability and stability, it is preferable to perform the local heating by using infrared heaters arranged in the width direction and the longitudinal direction of the film.

In the protrusion adjusting step, the film is stretched while locally heating the film in the stretching apparatus.

In this case, the film thickness profile of the target film in the width direction was measured using an on-line retardation/film thickness measuring device RE-200L 2T-rth+film thickness (manufactured by large-scale electronics, inc.) and the difference between the film thickness profile and the target film thickness profile was calculated on a computer, the set temperature of each infrared heater was outputted via PLC KV-8000 (manufactured by KEYENCE, inc.), the set temperature of each heat source was adjusted, and the protrusion was automatically repeated to automatically adjust the film thickness.

(1.2.2) stretching of film

The stretching of the film may be performed in the MD direction only, in the TD direction only, in both the MD direction and the TD direction, or in an oblique direction.

The stretching direction is not limited, but it is preferable to stretch at least in the width direction from the viewpoint of obtaining a wide film.

In order to improve the performance, productivity, flatness, and dimensional stability of the film, the stretching method is preferably a method in which the peripheral speed of the rolls is set so as to stretch in the transport direction (the longitudinal direction of the film; the film-forming direction; the casting direction; the MD direction); the film F is fixed at both side edges thereof by a jig or the like, and stretched in the width direction (direction perpendicular to the film surface; TD direction).

In addition, in the case of the so-called tenter method, if the clamp portion is driven by a linear drive system, smooth stretching can be performed, and the risk of breakage or the like can be reduced, which is preferable.

The width retention and the stretching in the transverse direction in the film forming step are preferably performed by a tenter stretching device, and may be a pin tenter or a clip tenter.

In addition to stretching, the tenter stretching device 7 may be used for drying.

(draw ratio)

In order to ensure a high retardation, a wide width, and promote penetration of an adhesive at the time of adhesion to the polarizer layer, it is preferable to stretch the film at a high magnification in the stretching step.

However, if the stretching ratio is too high, cracks may be generated in the film due to the stretching stress, or entanglement between molecules of the matrix which maintains the strength of the film may be dissociated, and the film may be weakened.

Therefore, the stretching ratio of the film is preferably in the range of 1.1 to 5.0 times, more preferably in the range of 1.3 to 3.0 times.

In the case of performing the stretching multiple times, it is preferable that the stretching of the highest magnification in which the risk of dissociation of the matrix molecule is highest among the stretching multiple times is performed at the final time.

(residual solvent amount at film stretching)

The amount of the residual solvent in the film at the time of stretching is preferably 20 mass% or less, more preferably 15 mass% or less.

(1.2.3) definition of terms in the protrusion adjustment step

(definition of terms relating to the convex portions)

The definition of the term concerning the convex portion is omitted because it is described above.

( Continuity of the convex portion in the length direction: adjustment of the position of the protruding portion in the longitudinal direction )

The position of the convex portion adjusted in the convex portion adjustment step according to the present invention is adjusted so as to continuously move in the longitudinal direction of the film surface, and the position of the convex portion is determined according to the definition described later, and if the positions of the convex portions are connected to each other, a substantially straight line trajectory is drawn as shown in fig. 4A and 4B, for example. Alternatively, as shown in fig. 4C, a trajectory having a curve with a curvature that changes at a substantially constant rate of change is drawn.

In fig. 4A, 4B, and 4C, the scale width in the width direction and the length direction is changed for convenience in understanding the present invention.

Accordingly, the expression "continuously move in the longitudinal direction of the film surface" according to the present invention means that a locus of a substantially straight line or a curve having a curvature that changes at a substantially constant rate of change is drawn when the positions of the convex portions are connected to each other, as described above. The substantially straight line or the curve having the curvature varying at a substantially constant rate of change may have periodicity.

Fig. 4A, 4B, and 4C show a connection of the convex portions having periodicity, but are not limited to the connection having periodicity.

As shown in fig. 5, the "substantially straight line" refers to a line that can be considered as a substantially straight line when viewed from the point of escape from the straight line in a strict sense, as well as the control conditions of the convex portion adjustment step and fluctuation in the properties of the film when the center point of each convex portion is plotted by taking the width direction of the film as the horizontal axis (x-axis) and the length direction of the film as the vertical axis (y-axis).

When the approximate straight line is used as the approximate straight line obtained by the least square method, the absolute value of the coefficient of correlation representing the approximate straight line is preferably 0.8 or more.

The "substantially constant rate of change" refers to a rate of change within a range of ±10% of the average value.

(inclination angle θ' of a substantially straight line with respect to the longitudinal direction of the film surface)

In the convex portion adjustment step according to the present invention, from the viewpoint of the effect of the present invention, it is preferable that the positions of the convex portions are adjusted so as to be aligned in a substantially straight line in the longitudinal direction of the film surface by locally heating the film.

By controlling the convex portion as described above, the film thickness profile in the longitudinal direction of the film is not drastically changed, and the effect of the present invention is further improved by maintaining the continuity of the convex portion.

From the viewpoint of exhibiting the effect of the present invention, the absolute value of the inclination angle of the substantially straight line is preferably in the range of 0.01 to 0.6 °.

The inclination angle θ' of the substantially straight line with respect to the longitudinal direction of the film surface according to the present invention is confirmed as follows.

As shown in fig. 5, the positions of the convex portions calculated from the film thickness profile and the average film thickness measured by the on-line retardation/film thickness measuring apparatus RE-200L2T-rth+ film thickness (manufactured by tsuka electronics, inc.) are plotted with the width direction of the film being the horizontal axis (x-axis) and the longitudinal direction of the film being the vertical axis (y-axis).

The position of the convex part at any position of the end part of the film is set as P ₀ (x ₀ ，y ₀ ) The coordinates of other convex parts are plotted as P ₁ (x ₁ ，y ₁ )、P ₂ (x ₂ ，y ₂ )、·····、P _n (x _n ，y _n )(n is an integer of 1 or more).

Fig. 5 shows a relationship with a drawing of the position of the convex portion obtained by the above-described operation, which approximates a straight line.

The locus of the convex part drawn as described above is used to set the position of the convex part at any position of the end part of the film as P ₀ (x ₀ ，y ₀ )＝P ₀ (0, 0), drawing a straight line (correlation coefficient R is 0.9 or more) in which the slope of an approximate straight line obtained by the least square method is represented by a linear function y=ax (x and y are variables) of a, and obtaining an angle θ [ ° corresponding to the slope a at that time]。

At this time, the inclination angle θ '[ ° ] of the substantially straight line with respect to the longitudinal direction of the film surface becomes θ' [ ° = (90- θ) [ ° ].

(heat source E) _A And E is _B Average inclination angle θ of straight line of connection with respect to straight line in length direction _E ′)

In the present invention, from the viewpoint of the effect of the present invention, it is preferable that the heat source units of the infrared heater are arranged at intervals of 10 to 100mm in the width direction of the film, and the heat source units are arranged at positions different from the width positions in the longitudinal direction of the film, and each of the arranged heat source units E _A And E is _B Average inclination angle θ of straight lines connecting _E ' in the range of 2 to 45 DEG relative to the longitudinal direction.

The distance between the heat source units of the infrared heater is set to be smaller, and the distance can be adjusted to a small profile.

The infrared heaters on the film are arranged in 1 or more rows in the longitudinal direction of the film as shown in fig. 6A, 6B, and 6C, for example (1 row in the longitudinal direction of the film in fig. 6A, 2 rows in the longitudinal direction of the film in fig. 6B, and 5 rows in the longitudinal direction of the film in fig. 6C).

In fig. 6, P1, P2, and P3 denote pitches of the heat source portions of the respective infrared heaters at which intervals are provided.

As can be seen from fig. 6A, 6B, and 6C, each heat source portion in the infrared heater is a central portion of each infrared heater.

The shape of the infrared heater in the present invention is not limited, and the actual heat source portion of the infrared heater may be a dot, a line, or a plane.

The infrared heater is disposed at a distance of 30 to 120mm from the film surface.

The heating width is set to be in the range of 100 to 250 mm.

Further, the heat source unit arrangement interval of the infrared heater is set to be in the range of 10 to 100 mm.

Each heat source part of the infrared heater is set to be in the range of 180-350 ℃ in the range of 100-1000W.

The positional relationship of each heat source unit will be specifically described below.

In the determination of each heat source E to be disposed according to the present invention _A And E is _B Average inclination angle θ of straight lines connecting _E ' in the case of the heat source E _A And E is connected with _B The positional relationship of (a) is the nearest positional relationship in which the coordinate in the width direction and the coordinate in the length direction are different in position (see fig. 6).

Specifically, for example, the positional relationship shown in fig. 7A and 7B can be exemplified.

The heat source units E are arranged _A And E is _B Average inclination angle θ of straight line of connection with respect to straight line in length direction _E ' derived as described below.

The following description will be made with reference to fig. 7A.

As shown in fig. 7A, the heat source unit E is set to take the x-axis in the width direction of the film and the y-axis in the longitudinal direction _A The coordinates of (2) are set to (x) ₁ ，y ₁ ) Heat source unit E _B The coordinates of (2) are set to (x) ₂ ，y ₂ )。

By combining |x ₂ -x ₁ The I is set to be triangle Bottom edge, y ₂ -y ₁ Angle θ derived when i is set to the height of triangle _E [°]The value of (0 DEG is more than or equal to theta is less than or equal to 90 DEG), and 90-theta is calculated _E [°]To derive the average inclination angle theta of the straight line _E ′。

Film thickness control means in protrusion adjustment step

(film thickness control means 4)

The film thickness control means in the convex portion adjustment step can be performed by, for example, changing the temperature in the furnace and the timing of the heat treatment in the tenter stretching apparatus.

In the present invention, the heat treatment is performed by an Infrared (IR) heater, or by other methods.

The film thickness control means 4 can be performed by changing the temperature of the atmosphere and the timing of the heat treatment in the furnace in other steps, even if the tenter stretching apparatus is not in the furnace.

(tenter stretching device)

[ temperature in furnace ]

The in-furnace temperature as defined in the present application means a temperature at a position 100mm upward from the center of the film immediately before the film passes through the stretching zone (for the stretching zone, described later), measured in a tenter stretching apparatus, and the average value of each temperature was calculated by measuring the temperature at 1 minute intervals for 1 hour.

If the difference between the above-mentioned furnace temperature and the heat treatment temperature is not too small or too large, the adjustment of the convex portion becomes easy.

From the above point of view, the difference between the temperature in the furnace and the temperature of the heat treatment is preferably in the range of 100 to 200 ℃.

In general, the temperature in the furnace is preferably in the range of 120 to 220 ℃, more preferably in the range of 120 to 180 ℃.

Among the plurality of compartments, the compartment subjected to the heat treatment is targeted when a temperature gradient is applied in the longitudinal direction.

[ residual solvent amount immediately before passing the film through the stretching zone ]

The amount of the residual solvent in the film immediately before the film passes through the stretching region is preferably 20 mass% or less, more preferably 15 mass% or less.

[ internal Structure of tentering stretching device 1]

The tenter stretching device stretches the film by holding both ends of the film in the width direction with jigs and expanding the interval while advancing the jigs together with the film, and is generally divided into a plurality of regions (preheating region, stretching region, and heat setting region), and is carried out by changing the timing of heat treatment in the 3 regions as needed.

In the heat treatment described above, infrared (IR) heaters are used, and the number of the Infrared (IR) heaters is appropriately set for each region as needed.

However, as a heat treatment method in the present invention, a heat treatment method other than an Infrared (IR) heater may be used.

The apparatus used as the tenter stretching apparatus 7 will be described below with reference to fig. 8.

Fig. 8 is a plan view schematically showing the internal structure of the tenter stretching device, and is a cross-sectional view of a surface of the tenter stretching device perpendicular to the surface of the film, as viewed from above.

Fig. 8 shows a state where the cover is removed, and the cover is shown by a two-dot chain line.

The tenter stretching device 40 includes a plurality of clips 42 for holding both ends of the film F in the width direction, and the clips 42 are attached to an endless chain 48 at regular intervals.

The endless chain 48 is disposed on both sides with the film F interposed therebetween, and each is hung between the driving sprocket 50 on the inlet side and the driven sprocket 52 on the outlet side.

The drive sprocket 50 is connected to a motor, not shown, and the drive sprocket 50 is rotated by driving the motor.

Thus, the endless chain 48 travels around between the drive sprocket 50 and the driven sprocket 52, and thus the clips 42 mounted to the endless chain 48 travel around.

A track 54 for guiding the endless chain 48 (or the jig 42) is provided between the driving sprocket 50 and the driven sprocket 52.

The rails 54 are disposed on both sides so as to sandwich the film F, and the distance between the rails 54 is formed so as to be wider on the downstream side than on the upstream side in the conveying direction of the film F.

As a result, the interval between the clips 42 is enlarged when the clips 42 travel around, and therefore the optical film F held by the clips 42 can be stretched laterally in the width direction.

An open member 56 is attached to each of the driving sprocket 50 and the driven sprocket 52.

The opening member 56 is a device for displacing a shutter (not shown) of the gripper 42, which will be described later, from a gripping position to an opening position, and the gripping operation and the opening operation of the film F are automatically performed by using the opening member 56.

[ internal Structure of tentering stretching device 2]

As shown in fig. 8, the inside of the tenter stretching device 40 is provided with a preheating zone, (lateral) stretching zone and a heat fixing zone.

The regions are separated from each other by a blind (not shown).

In each region, hot air is supplied to the film F from above or below, or both.

The hot air is uniformly discharged in the width direction of the film F in a state where the hot air is controlled to a predetermined temperature in each region.

Thereby, the inside of each region is controlled to a desired temperature.

The following describes each region.

The preheating zone is a zone where the film F is preheated, and heats the film F without expanding the interval between the jigs 42.

The film F preheated in the preheating zone moves to the transverse stretching zone.

The transverse stretching region is a region in which the film F is transversely stretched in the width direction by expanding the interval of the clips 42.

The stretching ratio in 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.

The film F stretched in the transverse direction in the transverse stretching zone moves to the heat-set zone.

In the present embodiment, the interior of the tenter 40 is divided into a preheating zone, (transverse stretching zone) and a heat fixing zone, but the type and arrangement of the zones are not limited to this, and for example, a cooling zone for cooling the film F may be provided after the transverse stretching zone.

In addition, a heat moderating zone may be provided in the heat fixing zone.

In the present embodiment, only the transverse stretching is performed by the tenter 40, and the stretching may be performed simultaneously in the longitudinal direction.

In this case, the pitch of the jigs 42 (the interval between the jigs 42 in the conveying direction) may be changed at the time of movement of the jigs 42.

As a mechanism for changing the pitch of the jigs 42, for example, a zoom mechanism or a linear guide mechanism can be used.

[ internal Structure of tentering stretching device 3]

Fig. 9 is a schematic view of the nozzle and heater installation portion when the 3 regions in the tenter stretching device are viewed from the front.

Fig. 10 is a side view showing 3 areas in the tenter stretching device in which an Infrared (IR) heater is provided in the preheating zone, as an example of the case where an IR heater is provided in each area.

As shown in fig. 9, the Infrared (IR) heater is disposed only at the upper side of the nozzle so that the film does not contact the Infrared (IR) heater when the film breaks.

Further, when the Infrared (IR) heater is brought close to the film, the radiant energy generated by the Infrared (IR) heater can be concentrated in a narrower range, so that the Infrared (IR) heater is brought as close to the film as possible in a range where the widening operation by the jig is not interfered.

In FIG. 9, the distance H from the film to the Infrared (IR) heater _A Preferably in the range of 30 to 120 mm.

In addition, a heating width of 100 to 250mm is preferably used for the heating width of the Infrared (IR) heater.

The term "heating width" as used in the above description refers to a width heated by an Infrared (IR) heater until the heating intensity thereof becomes 0.2 when the heating intensity immediately below the IR heater is 1.

The setting interval (pitch) of the Infrared (IR) heater is preferably 10 to 100mm, and is preferably heated at 100 to 1000W in the range of 150 to 400 ℃.

In the present invention, the film thickness profile in the width direction of the film is measured at each position, the set temperature of each Infrared (IR) heater is calculated on a computer from the difference between the target film thickness profile and the current film thickness profile, the set temperature is outputted to each Infrared (IR) heater via KEYENCE PLC KV-8000, and these operations are automatically repeated to adjust the convex portion.

Fig. 9 mainly shows the heat treatment from the central nozzle, and in this example, the heat treatment using the end nozzle is not performed, but may be used in combination in the present embodiment.

In the stretching apparatus, as shown in fig. 10, when an Infrared (IR) heater is exposed from the nozzle slit, radiant energy can be transmitted to the film without waste.

Fig. 11 is a cross-sectional view of the tenter stretching device from above, as viewed from a plane perpendicular to the plane of the film from a point of view different from that of fig. 8.

As shown in fig. 11, in the film before stretching, infrared (IR) heaters are arranged in a row so that the entire width can be heated.

The heater may be arranged in a zigzag shape in the longitudinal direction.

(correlation between the heat quantity A at the center of the infrared heater and the average value B of the heat quantity at the ends of the infrared heater)

In the convex portion adjustment step (S2), it is preferable that the Infrared (IR) heater is used to perform local heating from the viewpoint of the effect appearance, and the average value B of the heat quantity a at the central portion and the heat quantity B at the end portion of the Infrared (IR) heater which is 75mm away from the central portion in the Infrared (IR) heater satisfies the following formula (1).

Formula (1): 0.2 < (B/A) < 0.6

If the convergence of heat generated by the irradiation light of the infrared rays generated by the infrared heater is good, finer film thickness profile adjustment can be performed, and therefore, the above-described range is effective in the present invention in consideration of the yield to such an extent that heat control is not excessively difficult.

The term "central portion in the Infrared (IR) heater" in the above description refers to each heat source portion in fig. 6.

The term "Infrared (IR) heater end portion" in the above description refers to a position 75mm in the width direction from the central portion.

In the present invention, the average value B of the heat quantity a of the central portion and the heat quantity B of the end portion of the Infrared (IR) heater is calculated by measuring the temperature distribution by an infrared thermal camera (VIM-640G 2ULC manufactured by fava, ltd.) and taking the average value, and when the heat treatment is performed by another method, this corresponds to this.

Hereinafter, the principle and calculation method thereof are shown in detail.

The film was heated using the above Infrared (IR) heater.

The temperature fluctuation range of the heated portion was accumulated in the longitudinal direction, the width center portion thereof was set as heat a, and the average value of the positions 75mm in the width direction was set as the average value B of the heat at the end portions of the infrared heater.

From the above values, the heat quantity ratio (B/a) of the heat quantity a of the central portion of the Infrared (IR) heater and the average value B of the heat quantity B of the end portions of the Infrared (IR) heater was calculated.

In this case, when (B/a) is too large, the Infrared (IR) heater is not designed so that the irradiation range of the infrared rays can be accurately narrowed, and when (B/a) is too small, the number of the Infrared (IR) heaters in the width direction is increased, whereby the range of the value of (B/a) can be controlled.

[ Infrared (IR) Heater ]

Details of an Infrared (IR) heater used in the present invention will be described.

As an Infrared (IR) heater that can be used in the practice of the present invention, it is preferable to use a mirror that reflects infrared rays, unlike a general Infrared (IR) heater, so that the irradiation range of infrared rays can be accurately narrowed.

Examples of the infrared reflecting mirror include a plurality of cold mirrors (manufactured by sigma-ray machine corporation) and infrared aluminum-augmented mirrors (ヴ on-off corporation).

As the mirror used in the implementation of the present invention, an infrared aluminum enhanced mirror (ヴ log-zep, manufactured by the company zep) is used as the mirror using aluminum.

The irradiation range of the infrared rays of the conventional general Infrared (IR) heater 1 is 500mm in the width direction under the irradiation energy of 400W (manufactured by nap chemical company) of MCHNNS3, for example, whereas the irradiation range of the infrared rays of the Infrared (IR) heater 1 used in the practice of the present invention is 100 to 150mm in the width direction under the irradiation energy of 550W (manufactured by nap chemical company).

(1.3) finishing step (S3)

In the trimming step (S3), the cut portions 8 formed by slitters cut (trim) both ends of the stretched film F in the width direction.

From the viewpoint of exhibiting the effect of the present invention, it is preferable that the film is not vibrated before the trimming.

In the present specification, "vibration" means to move the film itself in the width direction.

In the film F, the remaining portions after cutting of the both end portions of the film constitute product portions that become film products.

On the other hand, the portion cut from the film F is recovered and reused as a part of the raw material in the film production of the film.

The film may be knurled after the trimming step, and it is preferable not to knurl the film after the trimming step, from the viewpoint of suppressing excessive air intake.

(1.4) winding Process (S4)

Finally, in the winding step (S4), the film F is wound by the winding device 13 to obtain a film roll.

That is, in the winding step, the film F is wound around the winding core while being conveyed, thereby producing a film roll.

The initial tension at the time of winding the film in the winding step is preferably in the range of 20 to 300N/m.

(residual solvent amount immediately before coiling)

More specifically, in the step of winding the film by the winding device 12 after the amount of the residual solvent in the film is 2 mass% or less, the amount of the residual solvent is 0.4 mass% or less, whereby a film having good dimensional stability can be obtained.

In particular, the residual solvent amount is preferably in the range of 0.00 to 0.20 mass%.

(coiling method)

As a winding method of the film F, a winding machine commonly used may be used, and a method of controlling tension such as a constant torque method, a constant tension method, a taper tension method, a program tension control method in which internal stress is constant, and the like may be used separately.

Before winding, the film ends are slit into product widths and cut off, and surface modification treatment may be applied to the film ends to prevent sticking and scratching during winding.

(after coiling)

The film roll according to the present invention is preferably a long film, and specifically, a film in a range of about 100 to 10000m is usually provided in a roll form.

Details of film winding method

The film according to the present invention is preferably wound by the following winding method.

The winding method preferably includes: a straight winding step of winding the film around a winding core so that the side edges of the film are aligned; and a vibration winding step of periodically vibrating the film or the winding core in the width direction of the film so as to wind the film around the winding core so that the side edge is periodically deviated in a predetermined range with respect to the width direction of the film after the straight winding step.

In particular, it is preferable that the roll length of the film is in the range of 1 to 30% relative to the total roll length of the film, and when a predetermined roll length at the time of replacement is reached, the process is switched from the direct roll process to the vibratory roll process.

The film winding device preferably includes: a film winding section that rotates a winding core to wind a film around the winding core; a vibration unit that vibrates the film or the winding core in the width direction of the film in conjunction with winding of the film so as to cause the film to be wound in a vibration winding in which the film is periodically deviated in the width direction of the film over a certain range on the winding core; and a switching unit that switches winding of the film from the straight winding to the vibration winding when the winding length of the film reaches a predetermined switching winding length.

Details concerning vibration winding are omitted below.

Fig. 12 is a schematic diagram showing a process of winding a film and a cross section of a film roll according to the present invention after winding.

In fig. 11, a film 31 after film formation is wound up by a roll 32 and a touch roll 33 as a film roll 30.

2. Method for producing film roll by melt casting film forming method

The film according to the present invention can be formed by a melt-casting film-forming method.

The "melt-casting film forming method" is a method of heating and melting a composition containing a thermoplastic resin and the above-mentioned additives to a temperature at which fluidity is exhibited, and then casting the melt containing the thermoplastic resin in fluidity.

The molding method by heating and melting can be classified into a melt extrusion molding method, a compression molding method, a inflation method, an injection molding method, a blow molding method, a stretch molding method, and the like.

Among these molding methods, the melt extrusion method is preferable in terms of mechanical strength, surface accuracy, and the like.

The flow of the production process by the melt-casting film-forming method will be described below with reference to the same flow as that shown in fig. 2 for the above-described melt-casting film-forming method.

Fig. 13 is a schematic view of an apparatus for producing an optical film by a melt-casting film-forming method.

The solution casting film forming method will be described below with reference to fig. 2 and 13.

The method for manufacturing a film roll by a melt casting film forming method of the present invention comprises: a film forming step (S1), a convex portion adjusting step (S2), a trimming step (S3), and a winding step (S4).

(2.1) film Forming step (S1)

(2.1.1) melt extrusion of resin

At least the resin is melt extruded using an extruder 14 and molded on a casting drum 16.

The details of the resin that can be used in the present invention will be described later, and it is preferable to knead the resin in advance and granulate the resin, and the granulation can be performed by a known method.

For example, the dried resin, the plasticizer, and other additives are fed to an extruder by a feeder, kneaded by a single-screw extruder or a twin-screw extruder, extruded into a strand form from a casting die, and cut by water cooling or air cooling, whereby the pellets can be obtained.

The additive may be mixed in the resin before being fed to the extruder, or the additive and the resin may be fed to the extruder by separate feeders.

In addition, small amounts of additives such as particles and antioxidants are preferably mixed in advance in the resin for uniform mixing.

When the pellets are introduced from the feed hopper into the extruder, they are preferably dried, evacuated or under reduced pressure, under an inert gas atmosphere, and the like, to prevent oxidative decomposition.

In the extruder, it is preferable to process the resin at a low temperature in order to suppress shearing force and to granulate the resin so that the resin is not deteriorated (e.g., reduced molecular weight, colored, gel formed, etc.).

In the case of a twin-screw extruder, for example, a deep-groove screw is preferably used so as to rotate in the same direction.

The occlusion type is preferable from the viewpoint of uniformity of kneading.

When the resin/pellet is melted, it is preferable to remove foreign matters by filtration using a disc filter or the like.

Using the pellets obtained as described above, film formation was performed.

Needless to say, the resin (powder or the like) as a raw material may be directly fed to an extruder by a feeder without granulating, and directly formed into a film.

(2.1.2) casting and shaping of molten resin/pellet

The molten resin/pellet is cast into a film form from the casting die 15 by a pressurized quantitative gear pump or the like using a pipe, and the molten resin/pellet is cast from the casting die 15 at a casting position on an endless-moving rotary-driven stainless steel endless casting drum 16.

Then, the cast resin/pellet in a molten state is molded on the casting drum 16 to form a film F.

The inclination angle of the casting die 15, that is, the discharge direction of the molten resin/pellet from the casting die 15 to the support 16 is appropriately set so that the angle with respect to the normal line of the surface of the casting drum 16 (the surface on which the molten resin/pellet is cast) is in the range of 0 to 90 °.

The touch roll 16a, the cooling drum 17 of the auxiliary casting drum 16 may be formed into the film F singly or in combination as appropriate.

The film thickness control means and other matters in the film forming step are the same as those in the above-described process for producing a film roll by the solution casting film forming method, and the descriptions of the residual solvent amount, shrinkage, drying method, and the like are repeated, so that they are omitted.

(2.2) protruding portion adjustment step (S2)

The outline of the projection adjusting step in the projection adjusting step, details of the projection adjusting step, film stretching, definition of each term in the projection adjusting step, film thickness control means in the projection adjusting step, and other matters are omitted from description of the same steps as those of the above-described production steps of the film roll by the solution casting film forming method.

In the convex portion adjusting step, if local heating is applied to the film, the film is simultaneously stretched.

The film F is stretched by a stretching device 19.

In the stretching device 19, drying may be performed in addition to stretching.

(2.3) finishing step (S3)

In the trimming step (S3), the cutting portion 20 formed by the slitter cuts (trims) both ends of the film in the width direction of the film F.

In the trimming described above, from the viewpoint of exhibiting the effect of the present invention, it is preferable that the film is not vibrated or the film is not vibrated in the width direction of the film.

On the other hand, the portion cut from the film F may be recovered and reused as a part of the raw material in the film production of the film.

The film may be knurled after the finishing step, and it is preferable not to knurl the film after the finishing step from the viewpoint of exhibiting the effect of the present invention.

(2.4) winding Process (S4)

Finally, in the winding step (S4), the film F is wound by the winding device 23 to obtain a film roll.

That is, in the winding step, the film F is wound around the winding core while being conveyed, thereby manufacturing a film roll.

3. Projection adjusting system in film roll manufacturing

The present invention provides a convex portion adjustment system used in manufacturing a film roll, the convex portion adjustment system being used in manufacturing a film roll having a convex portion adjustment step of adjusting the number, height and position of convex portions in the width direction of a film surface, the convex portion adjustment system comprising: a film thickness obtaining means for obtaining a film thickness profile of the film in the convex portion adjusting step; a determination means for determining, based on the data of the film thickness profile, whether or not the number of the protrusions in the width direction is within a range of 1 to 10 ideal values per 1m and whether or not the height of the protrusions in the width direction is within a range of 0.05 to 0.50 [ mu ] m; and means for heating the film locally by using an infrared heater so that the number of the convex portions and the height of the convex portions are both within a range of the ideal value when the number of the convex portions and the height of the convex portions are both outside the range of the ideal value in the determination means.

(3.1) means for obtaining film thickness

(means 1)

As a film thickness obtaining means of the film in the convex portion adjusting system in the production of the film roll of the present invention, an on-line retardation/film thickness measuring device RE-200L2T-Rth+ film thickness (manufactured by Otsuka electronic Co., ltd.) was used for measurement.

Details of definition and the like of the term concerning the convex portion are as described above, and therefore omitted.

(means 2)

In the protrusion adjusting step, the film is stretched while locally heating the film in the stretching device.

(3.2) determination means

Judging according to the data of the film thickness profile: whether the number of the convex portions in the width direction is within a range of an ideal value of 1 to 10 per 1m and whether the height of the convex portions in the width direction is within a range of an ideal value of 0.05 to 0.50 μm.

(3.3) means for heating the film locally by an infrared heater

When one or both of the number of the convex portions and the height of the convex portions is out of the range of the ideal value, the set temperatures of the respective infrared heaters are calculated on a computer from the difference between the current film thickness profile and the current film thickness profile, and the respective set temperatures are outputted, and the infrared heaters are used to locally heat the film, so that the convex portions are adjusted, and the film thickness adjustment is automatically repeated and automatically performed.

4. Film-forming resins

(4.1) thermoplastic resin

The thermoplastic resin material used in the film according to the present invention is not limited as long as it is a material to be processed as a film roll after film formation.

For example, as thermoplastic resins used for polarizing plate applications, cellulose ester resins such as triacetyl cellulose (TAC), cellulose Acetate Propionate (CAP), and diacetyl cellulose (DAC), cyclic olefin resins (hereinafter also referred to as cycloolefin resins) such as cycloolefin polymers (cycloolefin resins (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.

In particular, in a film having a low elastic modulus, for example, a resin having an elastic modulus of less than 3.0GPa, it is difficult to alleviate stress at a plurality of portions of the film when forming a film roll, and the film is difficult to stretch in the width direction and the length direction, and the film cannot sufficiently absorb stress in the surface in a rolled state, and winding displacement is likely to occur.

In addition, when the film having a low elastic modulus is viewed from another point of view, if there is a difference in height between the longitudinal direction and the longitudinal direction of the film, the difference between the expansion and contraction at the high position and the expansion and contraction at the low position of the film becomes large.

Therefore, in the embodiment of the present invention, it is preferable to control the maximum height difference (P-V) of the length average film thickness to be in the range of 0.02 to 0.40 μm, and the present invention is effective for application to a film roll using a cycloolefin polymer (cycloolefin resin (COP)) which is a resin having a low elastic modulus, and polymethyl methacrylate (acrylic resin (PMMA)) as a thermoplastic resin.

However, cycloolefin resin (COP) is preferably used in terms of easy control of stretchability and crystallinity, easy penetration of an adhesive, and ensuring more excellent adhesion to the polarizer layer.

The film may be subjected to a surface modification treatment after production.

In addition, the effect of the present invention is valuable in the field of thin films.

The film thickness of the film is preferably in the range of 5 to 80. Mu.m, more preferably in the range of 10 to 65. Mu.m, and even more preferably in the range of 10 to 45. Mu.m.

If the film thickness is 5 μm or more, the rigidity of the film roll is high, and it becomes easy to maintain the roll shape.

If the film thickness is 80 μm or less, the quality is not excessively increased, and a long film roll can be easily produced.

(4.1.1) cycloolefin resin

The cycloolefin resin contained in the film roll according to the present invention is preferably a polymer of cycloolefin monomer or a copolymer of cycloolefin monomer and a copolymerizable monomer other than the cycloolefin monomer.

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

[ chemical 1]

General type (A-1)

In the general formula (A-1), R ¹ ～R ⁴ Each independently represents a hydrogen atom, a hydrocarbon group having 1 to 30 carbon atoms, or a polar group. p represents an integer of 0 to 2. However, R is ¹ ～R ⁴ Not all of them simultaneously representing hydrogen atoms, R ¹ And R is ² Not simultaneously representing hydrogen atoms, R ³ And R is ⁴ And does not simultaneously represent a hydrogen atom.

In the general formula (A-1), R is ¹ ～R ⁴ The hydrocarbyl group having 1 to 30 carbon atoms represented is preferably a hydrocarbyl group having 1 to 10 carbon atoms, for example, and more preferably a hydrocarbyl group having 1 to 5 carbon atoms.

The hydrocarbon group having 1 to 30 carbon atoms may further have a linking group containing, for example, a halogen atom, an oxygen atom, a nitrogen atom, a sulfur atom or a silicon atom.

Examples of such a linking group include a polar group having a valence of 2 such as a carbonyl group, an imino group, an ether bond, a silyl ether bond, or a thioether bond.

Examples of the hydrocarbon group having 1 to 30 carbon atoms include methyl, ethyl, propyl, butyl and the like.

In the general formula (A-1), R is ¹ ～R ⁴ Examples of the polar group include carboxyl group, hydroxyl group, alkoxy group, alkoxycarbonyl group, aryloxycarbonyl group, amino group, amido group and cyano group.

Among them, carboxyl group, hydroxyl group, alkoxycarbonyl group and aryloxycarbonyl group are preferable, and alkoxycarbonyl group and aryloxycarbonyl group are preferable from the viewpoint of securing solubility at the time of solution film formation.

From the viewpoint of improving the heat resistance of the film, p in the general formula (A-1) is preferably 1 or 2.

This is because if p is 1 or 2, the resulting polymer becomes bulky and the glass transition temperature tends to increase.

[ chemical 2]

General type (A-2)

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

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

R in the general formula (A-2) ⁶ Preferably represents a carboxyl group, a hydroxyl group, an alkoxycarbonyl group and an aryloxycarbonyl group, and more preferably an alkoxycarbonyl group and an aryloxycarbonyl group from the viewpoint of securing solubility in a solution for film formation.

P in the general formula (A-2) preferably represents 1 or 2 from the viewpoint of improving the heat resistance of the film.

This is because if p represents 1 or 2, the resulting polymer becomes bulky and the glass transition temperature tends to increase.

From the viewpoint of improving the solubility in an organic solvent, cycloolefin monomers having a structure represented by the general formula (A-2) are preferable.

In general, an organic compound has a decreased crystallinity due to a breakdown in symmetry, and thus has an improved solubility in an organic solvent.

R in the general formula (A-2) ⁵ And R is ⁶ In contrast, since the cyclic olefin monomer having the structure represented by the general formula (a-2) has low symmetry with respect to the symmetry axis of the molecule, which is substituted with only one ring constituting a carbon atom, the solution casting method is suitable for producing a film.

The content of the cycloolefin monomer having the structure represented by the general formula (A-2) in the polymer of cycloolefin monomers may be, for example, 70 mol% or more, preferably 80 mol% or more, and more preferably 100 mol% based on the total of all cycloolefin monomers constituting the cycloolefin resin.

If the cycloolefin monomer having the structure represented by the general formula (A-2) is contained at least a certain amount, the orientation of the resin is improved, and thus the retardation (retardation) value is liable to rise.

Specific examples of cycloolefin monomers having a structure represented by the general formula (A-1) are shown as exemplified compounds 1 to 14, and specific examples of cycloolefin monomers having a structure represented by the general formula (A-2) are shown as exemplified compounds 15 to 34.

[ chemical 3]

Examples of the copolymerizable monomer copolymerizable with the cycloolefin monomer include a copolymerizable monomer ring-opened copolymerizable with the cycloolefin monomer, a copolymerizable monomer addition-copolymerizable with the cycloolefin monomer, and the like.

Examples of the ring-opening copolymerizable monomer include cycloolefins such as cyclobutene, cyclopentene, cycloheptene, cyclooctene, and dicyclopentadiene.

Examples of the addition copolymerizable monomer include a compound containing an unsaturated double bond, a vinyl cyclic hydrocarbon monomer, a (meth) acrylate, and the like.

Examples of the unsaturated double bond-containing compound include an olefin compound having 2 to 12 carbon atoms (preferably 2 to 8 carbon atoms), and examples thereof include ethylene, propylene, butene and the like.

Examples of the vinyl-based cyclic hydrocarbon monomer include vinyl-based monomers such as 4-vinylcyclopentene and 2-methyl-4-isopropenylcyclopentene.

Examples of the (meth) acrylic acid ester include alkyl (meth) acrylic acid esters having 1 to 20 carbon atoms such as methyl (meth) acrylate, 2-ethylhexyl (meth) acrylate, and cyclohexyl (meth) acrylate.

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

The cycloolefin resin is a polymer obtained by polymerizing or copolymerizing cycloolefin monomers having a norbornene skeleton, preferably cycloolefin monomers having a structure represented by the general formula (A-1) or (A-2), as described above, and examples thereof include the following polymers (1) to (7).

(1) Ring-opened polymers of cycloolefin monomers

(2) Ring-opened copolymer of cycloolefin monomer and copolymerizable monomer ring-opened copolymerizable therewith

(3) Hydrogenated product of the ring-opened (co) polymer of the above (1) or (2)

(4) Cyclizing the ring-opened (co) polymer of the above (1) or (2) by Fu Lie Deltakoff reaction to obtain a hydrogenated (co) polymer

(5) Saturated copolymers of cycloolefin monomers with compounds containing unsaturated double bonds

(6) Addition copolymer of cycloolefin monomer and vinyl cyclic hydrocarbon monomer and hydrogenated product thereof

(7) Alternating copolymers of cycloolefin monomers with (meth) acrylic esters

The polymers (1) to (7) can be obtained by any known method, for example, the method described in Japanese patent application laid-open No. 2008-107534 and Japanese patent application laid-open No. 2005-227606.

For example, the catalyst and solvent used in the ring-opening copolymerization of (2) can be, for example, the catalyst and solvent described in paragraphs 0019 to 0024 of Japanese patent application laid-open No. 2008-107534.

The catalysts used for the hydrides of (3) and (6) can be, for example, the catalysts described in paragraphs 0025 to 0028 of Japanese patent application laid-open No. 2008-107534.

The acidic compound used in the Fu Lie Deltaz reaction of (4) can be, for example, an acidic compound described in paragraph 0029 of Japanese patent application laid-open No. 2008-107534.

The catalysts used in the addition polymerization of the above-mentioned items (5) to (7) can be, for example, catalysts described in paragraphs 0058 to 0063 of Japanese patent application laid-open No. 2005-227606.

The above-mentioned alternating copolymerization reaction of (7) can be carried out by the method described in paragraphs 0071 and 0072 of Japanese patent application laid-open No. 2005-227606.

Among them, the polymers of the above (1) to (3) and (5) are preferable, and the polymers of the above (3) and (5) are more preferable.

That is, from the viewpoint of being able to raise the glass transition temperature of the resulting cycloolefin resin and to improve the light transmittance, the cycloolefin resin preferably contains 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 contains only the structural unit represented by the general formula (B-2), or contains both the structural unit represented by the general formula (B-1) and the structural unit represented by the general formula (B-2).

The structural unit represented by the general formula (B-1) is a structural unit derived from the cycloolefin monomer represented by the general formula (A-1), and the structural unit represented by the general formula (B-2) is a structural unit derived from the cycloolefin monomer represented by the general formula (A-2).

[ chemical 4]

General type (B-1)

In the general formula (B-1), X represents-CH=CH-or-CH =CH ₂ CH ₂ -。R ¹ ～R ⁴ And p is independently of R of the formula (A-1) ¹ ～R ⁴ Synonymous with p.

[ chemical 5]

General type (B-2)

In the general formula (B-2), X represents-CH=CH-or-CH =CH ₂ CH ₂ -。R ⁵ ～R ⁶ And p is independently of R of the formula (A-2) ⁵ ～R ⁶ Synonymous with p.

The cycloolefin resin according to the present invention can be commercially available.

Examples of commercial products of cycloolefin resins include a metal oxide film (a) G (for example, G7810, etc.), metal oxide film (a) F, metal oxide film (a) R (for example, R4500, R4900, R5000, etc.), and metal oxide film (a) RX, which are manufactured by JSR (strain).

Intrinsic viscosity [ eta ] of cycloolefin resin]inh is preferably 0.2 to 5cm in a measurement at 30 DEG C ³ In the range of/g, more preferably 0.3 to 3cm ³ In the range of/g, it is more preferably 0.4 to 1.5cm ³ In the range of/g.

The number average molecular weight (Mn) of the cycloolefin resin is preferably 8000 to 100000, more preferably 10000 to 80000, and even more preferably 12000 to 50000.

The weight average molecular weight (Mw) of the cycloolefin resin is preferably in the range of 20000 to 300000, more preferably in the range of 30000 to 250000, and even more preferably in the range of 40000 to 200000.

The number average molecular weight and the weight average molecular weight of the cycloolefin resin can be measured by polystyrene conversion in Gel Permeation Chromatography (GPC).

(gel permeation chromatography)

Solvent: dichloromethane (dichloromethane)

Column: shodex K806, K805, K803G (3 pieces of Shodex K.K.)

Column temperature: 25 DEG C

Sample concentration: 0.1 mass%

A detector: RI Model 504 (GL Science Co., ltd.)

And (3) a pump: l6000 (Hitachi manufacturing Co., ltd.)

Flow rate: 1.0 ml/min

Calibration curve: calibration curves for 13 samples in the range of mw=500 to 2800000 using standard polystyrene STKs tandard polystyrene (manufactured by eason corporation) were used. The 13 samples are preferably used at substantially equal intervals.

If the intrinsic viscosity [ eta ] inh, the number average molecular weight and the weight average molecular weight are within the above-mentioned ranges, the cycloolefin resin is excellent in heat resistance, water resistance, chemical resistance, mechanical properties and molding processability as a film.

The cycloolefin resin has a glass transition temperature (Tg) of usually 110℃or higher, preferably 110 to 350℃and more preferably 120 to 250℃and still more preferably 120 to 220 ℃.

If the glass transition temperature (Tg) is 110℃or higher, deformation under high temperature conditions is easily suppressed.

On the other hand, if the glass transition temperature (Tg) is 350 ℃ or lower, molding processing becomes easy, and deterioration of the resin due to heat during molding processing is also easily suppressed.

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

(4.1.2) acrylic resin

The acrylic resin according to the present invention is a polymer of acrylic acid ester or methacrylic acid ester, and also includes a copolymer with other monomers.

Therefore, the acrylic resin according to the present invention also includes a methacrylic resin.

The resin is not particularly limited, and preferably a resin having methyl methacrylate units in the range of 50 to 99 mass% and other monomer units copolymerizable therewith in the range of 1 to 50 mass%.

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

The copolymerizable monomer forming the unit excluding glutarimide and glutarimide from the above units includes monomers corresponding to the above units.

Specifically, examples thereof include alkyl methacrylates having 2 to 18 carbon atoms, alkyl acrylates having 1 to 18 carbon atoms, isobornyl methacrylate, hydroxyalkyl acrylates such as 2-hydroxyethyl acrylate, α, β -unsaturated acids such as acrylic acid and methacrylic acid, acrylamides such as acryloylmorpholine and N-hydroxyphenylmethacrylamide, aromatic vinyl compounds such as 2-valent carboxylic acids containing an unsaturated group such as maleic acid, fumaric acid and itaconic acid, styrene and α -methylstyrene, α, β -unsaturated nitriles such as acrylonitrile and methacrylonitrile, maleic anhydride, maleimide and N-substituted maleimide.

Further, glutarimide units can be formed by, for example, reacting an intermediate polymer having a (meth) acrylate unit with a primary amine (imidizing agent) to imidize (refer to japanese patent application laid-open No. 2011-26563).

The glutaric anhydride unit can be formed by, for example, heating an intermediate polymer having a (meth) acrylate unit (see japanese patent No. 4961164).

Among the above structural units, the acrylic resin according to the present invention particularly preferably contains isobornyl methacrylate, acryloylmorpholine, N-hydroxyphenylmethacrylamide, N-vinylpyrrolidone, styrene, hydroxyethyl methacrylate, maleic anhydride, maleimide, N-substituted maleimide, glutaric anhydride or glutarimide from the viewpoint of mechanical strength.

The acrylic resin according to the present invention is preferably in the range of a weight average molecular weight (Mw) of 50000 ～ 1000000, more preferably in the range of 100000 ～ 1000000, and particularly preferably in the range of 200000 ～ 800000, from the viewpoints of controlling dimensional changes with respect to changes in the atmospheric temperature and humidity of the environment, and from the viewpoints of releasability from a metal support at the time of film production, drying property of an organic solvent, heat resistance, and improvement of mechanical strength.

When the amount is 50000 or more, the heat resistance and mechanical strength are excellent, and when the amount is 1000000 or less, the releasability from the metal support and the drying property of the organic solvent are excellent.

The method for producing the acrylic resin according to the present invention is not particularly limited, and any known method such as suspension polymerization, emulsion polymerization, bulk polymerization, or solution polymerization may be used.

Among them, as the polymerization initiator, a general peroxide-based or azo-based polymerization initiator can be used, and a redox-based polymerization initiator can be used.

The polymerization temperature may be in the range of 30 to 100℃in suspension or emulsion polymerization, and 80 to 160℃in bulk or solution polymerization.

In order to control the reduction viscosity of the resulting copolymer, a chain transfer agent such as an alkyl mercaptan may be used to carry out the polymerization.

From the viewpoint of maintaining the mechanical strength of the film, the glass transition temperature (Tg) of the acrylic resin is preferably in the range of 80 to 120 ℃.

As the acrylic resin according to the present invention, commercially available products can be used.

Examples thereof include DELMET 60N, 80N, 980N, SR8200 (manufactured by Asahi chemical Co., ltd.), dianal BR52, BR80, BR83, BR85, BR88, EMB-143, EMB-159, EMB-160, EMB-161, EMB-218, EMB-229, EMB-270, EMB-273 (manufactured by Mitsubishi rayon Co., ltd.), KT75, TX400S, and IPX012 (manufactured by electric chemical industries Co., ltd.).

Two or more types of acrylic resins may be used in combination.

The acrylic resin according to the present invention preferably contains an additive, and as an example of the additive, it is preferable to contain acrylic particles (rubber elastomer particles) described in international publication No. 2010/001668 in order to improve the mechanical strength of the film and adjust the dimensional change rate.

Examples of such a commercially available acrylic granular composite having a multilayer structure include "METABLEN W-341" manufactured by Mitsubishi rayon, "cover" manufactured by Zhong Hua, and "Paraloid" manufactured by Wu Yu, and "ALLOY" manufactured by Robin Hash, AICA, and "STAPHYLOID" manufactured by Chemisnow MR-2G, MS-300X (the above are manufactured by Zygen chemical Co., ltd.), and "PARAPET SA" manufactured by colali, etc., which may be used alone or in combination of two or more.

The volume average particle diameter of the acrylic particles is 0.35 μm or less, preferably 0.01 to 0.35 μm, more preferably 0.05 to 0.30 μm.

If the particle size is not less than a certain value, the film can be easily stretched by heating, and if the particle size is not more than a certain value, the transparency of the obtained film is not easily impaired.

From the viewpoint of flexibility, the film according to the present invention preferably has a flexural modulus (JIS K7171) of 10.5GPa or less.

The flexural modulus is more preferably 1.3GPa or less, and still more preferably 1.2GPa or less.

The flexural modulus varies depending on the type and amount of the acrylic resin and the rubber elastomer particles in the film, and generally decreases as the content of the rubber elastomer particles increases.

In addition, when a copolymer of an alkyl methacrylate and an alkyl acrylate or the like is used as the acrylic resin, the flexural modulus is generally smaller than when a homopolymer of an alkyl methacrylate is used.

(4.1.3) cellulose ester-based resin

In the film roll according to the present invention, a cellulose ester resin is preferably used.

The cellulose ester used in the present invention means a cellulose acylate resin in which part or all of hydrogen atoms of hydroxyl groups (-OH) at the 2-position, 3-position and 6-position in glucose units combined with beta-1, 4 constituting cellulose are substituted with acyl groups.

The cellulose ester to be used is not particularly limited, but is preferably an ester of a linear or branched carboxylic acid having about 2 to 22 carbon atoms.

The carboxylic acid constituting the ester may be an aliphatic carboxylic acid, a ring-formed carboxylic acid, or an aromatic carboxylic acid.

Examples thereof include cellulose esters in which a hydrogen atom of a hydroxyl group of cellulose is substituted with an acyl group having 2 to 22 carbon atoms such as acetyl, propionyl, butyryl, isobutyryl, pentanoyl, pivaloyl, hexanoyl, octanoyl, lauroyl, and stearoyl.

The carboxylic acid (acyl group) constituting the ester may have a substituent.

The carboxylic acid constituting the ester is particularly preferably a lower fatty acid having 6 or less carbon atoms, and more preferably a lower fatty acid having 3 or less carbon atoms.

The acyl group in the cellulose ester may be one or a combination of a plurality of acyl groups.

Specific examples of the preferred cellulose ester include cellulose acetate such as diacetyl cellulose (DAC) and triacetyl cellulose (TAC), cellulose Acetate Propionate (CAP), cellulose acetate butyrate, and cellulose acetate propionate butyrate, and mixed fatty acid esters of cellulose having a propionate group or a butyrate group bonded thereto in addition to an acetyl group.

These cellulose esters may be used singly or in combination.

(species of acyl group, substitution degree)

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

The smaller the degree of substitution of the acyl group of the cellulose ester, the more the retardation appearance improves, and thus the film can be made thinner.

On the other hand, if the substitution degree of the acyl group is too small, there is a possibility that durability is deteriorated, which is not preferable.

On the other hand, the higher the degree of substitution of acyl groups of cellulose esters, the less the retardation will develop, and therefore the stretching ratio must be increased at the time of film formation, but it is difficult to uniformly stretch at a high stretching ratio, and therefore the film thickness variation increases (worsens).

Further, since the variation in Rt humidity, which is the retardation (retardation) in the thickness direction, occurs due to the coordination of water molecules to the carbonyl groups of cellulose, the higher the degree of substitution of acyl groups, that is, the more carbonyl groups in cellulose, the worse the variation in Rt humidity tends to be.

The cellulose ester preferably has a total substitution degree in the range of 2.1 to 2.5.

By setting the thickness to this range, the uniformity of the film thickness can be improved while suppressing environmental fluctuations (particularly, rt fluctuations due to humidity).

More preferably, the thickness is in the range of 2.2 to 2.45 from the viewpoint of further improving the ductility and stretchability at the time of film formation and uniformity of film thickness.

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

Formula (a): X+Y is more than or equal to 2.1 and less than or equal to 2.5

Formula (b): y is more than or equal to 0 and less than or equal to 1.5

Cellulose esters are more preferably cellulose acetate (y=0) and Cellulose Acetate Propionate (CAP) (Y: propionyl, Y > 0), and from the viewpoint of reducing film thickness deviation, more preferably cellulose acetate with y=0.

From the viewpoint of bringing the retardation manifestability, the variation in Rt humidity, and the film thickness deviation to the desired ranges, it is particularly preferable to use cellulose acetate (DAC) in which X is 2.1.ltoreq.2.5 (more preferably, 2.15.ltoreq.x.ltoreq.2.45).

In addition, when Y > 0, cellulose Acetate Propionate (CAP) is particularly preferably used in which X is 0.95.ltoreq.X.ltoreq.2.25, Y is 0.1.ltoreq.1.2, and X+Y is 2.15.ltoreq.2.45.

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

The substitution degree of the acyl group means the average number of acyl groups per 1 glucose unit, and means that several of the hydrogen atoms of the hydroxyl groups at the 2-, 3-and 6-positions of the 1 glucose unit are substituted with the acyl group.

Therefore, the maximum substitution degree is 3.0, which means that all of the hydrogen atoms of the hydroxyl groups at the 2-position, 3-position and 6-position are substituted with acyl groups.

These acyl groups may be substituted at the 2-, 3-, and 6-positions of the glucose unit on average, or may be substituted with a distributed substituent.

The degree of substitution was determined by the method specified in ASTM-D817-96.

In order to obtain the desired optical characteristics, cellulose acetate having different degrees of substitution may be mixed and used.

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

In the case of the number average molecular weight (Mn) of the cellulose ester, if it is 2X 10 ⁴ ～3×10 ⁵ Within (2X 10), and further ⁴ ～1.2×10 ⁵ Within a range of (2), and further 4 x 10 ⁴ ～8×10 ⁴ In (2), the mechanical strength of the resulting film roll is preferably increased.

The number average molecular weight Mn of the cellulose ester is calculated by measurement using Gel Permeation Chromatography (GPC) using the above measurement conditions.

In the case of the weight average molecular weight (Mw) of the cellulose ester, if it is 2X 10 ⁴ ～1×10 ⁶ Within (2X 10), and further ⁴ ～1.2×10 ⁵ Within a range of (2), and further 4 x 10 ⁴ ～8×10 ⁴ In (2), the mechanical strength of the resulting film roll is preferably increased.

The cellulose ester is not particularly limited, and examples thereof include cotton linter, wood pulp, kenaf, and the like.

The cellulose esters obtained from these may be used in any ratio.

Cellulose esters such as cellulose acetate and cellulose acetate propionate can be produced by a known method.

In general, cellulose as a raw material is mixed with a predetermined organic acid (acetic acid, propionic acid, etc.), an acid anhydride (acetic anhydride, propionic anhydride, etc.), and a catalyst (sulfuric acid, etc.), and then the mixture is esterified to react until a triester of cellulose is formed.

In triesters, three hydroxyl groups of the glucose unit are replaced with acyl groups of the organic acid.

If two organic acids are used simultaneously, a cellulose ester of mixed esters, such as cellulose acetate propionate, cellulose acetate butyrate, can be produced.

Then, a cellulose ester resin having a desired degree of acyl substitution is synthesized by hydrolyzing a triester of cellulose.

Then, the cellulose ester resin is completed through the procedures of filtration, precipitation, water washing, dehydration, drying and the like. Specifically, the synthesis can be performed by the method described in Japanese patent laid-open No. 10-45804.

(4.2) other additives

The film roll according to the present invention may contain, as other additives, the following additives in addition to the thermoplastic resin described above.

(4.2.1) plasticizers

The film roll according to the present invention preferably contains at least one plasticizer, for example, in order to impart processability to a polarizer protective film or the like.

The plasticizer is preferably used singly or in combination of two or more.

Among the plasticizers, a plasticizer containing at least one selected from the group consisting of sugar esters, polyesters, and styrene compounds is preferable from the viewpoint of achieving both efficient control of moisture permeability and compatibility with a base resin such as cellulose ester.

From the viewpoint of improving the wet heat resistance and compatibility with a base resin such as cellulose ester, the molecular weight of the plasticizer is preferably 15000 or less, more preferably 10000 or less.

In the case where the compound having a molecular weight of 10000 or less is a polymer, the weight average molecular weight (Mw) is preferably 10000 or less.

The weight average molecular weight (Mw) is preferably in the range of 100 to 10000, more preferably 400 to 8000.

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

The inclusion of the water-repellent agent in the above range is preferable because both effective control of moisture permeability and compatibility with the base resin can be achieved.

Sugar ester

The film roll according to the present invention may contain a sugar ester compound in order to prevent hydrolysis.

Specifically, as the sugar ester compound, a sugar ester having at least one of a pyranose structure or a furanose structure of 1 to 12, and having all or part of the OH groups of the structure thereof esterified can be used.

Polyester

The film roll according to the present invention may contain polyester.

The polyester is not particularly limited, and for example, a polymer having a hydroxyl group at the end (polyester polyol) obtained by a condensation reaction of a dicarboxylic acid or an ester-forming derivative thereof with a diol, or a polymer having a hydroxyl group at the end of the polyester polyol blocked with a monocarboxylic acid (end-capped polyester) can be used.

The ester-forming derivative herein is an ester of a dicarboxylic acid, a dicarboxylic acid chloride, or an anhydride of a dicarboxylic acid.

Styrene compound

In the film roll according to the present invention, a styrene compound may be used in addition to or instead of the sugar ester and polyester for the purpose of improving the water resistance of the film.

The styrene compound may be a homopolymer of a styrene monomer or a copolymer of a styrene monomer and a comonomer other than the styrene monomer.

The content of the structural unit derived from the styrene monomer in the styrene compound may be in the range of preferably 30 to 100 mol%, more preferably 50 to 100 mol%, in order to have a large volume of a molecular structure of a certain or more.

In the example of the styrene-based monomer, styrene is contained; alkyl-substituted styrenes such as α -methylstyrene, β -methylstyrene and p-methylstyrene; halogen-substituted styrenes such as 4-chlorostyrene and 4-bromostyrene; hydroxystyrenes such as p-hydroxystyrene, α -methyl-p-hydroxystyrene, 2-methyl-4-hydroxystyrene, and 3, 4-dihydroxystyrene; vinyl benzyl alcohol; alkoxy-substituted styrenes such as p-methoxystyrene, p-t-butoxystyrene and m-t-butoxystyrene; vinyl benzoic acids such as 3-vinyl benzoic acid and 4-vinyl benzoic acid; 4-vinylbenzyl acetate; 4-acetoxystyrene; amido styrenes such as 2-butyrylaminosttyrene, 4-formylaminosttyrene, and p-sulfonylaminostyrene; aminostyrenes such as 3-aminostyrene, 4-aminostyrene, 2-isopropenylaniline, and vinylbenzyl dimethylamine; nitrostyrenes such as 3-nitrostyrene and 4-nitrostyrene; cyanostyrenes such as 3-cyanostyrene and 4-cyanostyrene; vinyl phenyl acetonitrile; aryl styrenes such as phenyl styrene, indenes, and the like.

The styrene monomer may be one kind or two or more kinds.

(4.2.2) optional ingredients

The film roll according to the present invention may contain other optional components such as antioxidants, colorants, ultraviolet absorbers, matting agents, acrylic particles, hydrogen-binding solvents, and ionic surfactants.

These components can be added in the range of 0.01 to 20 parts by mass per 100 parts by mass of the base resin.

(antioxidant)

The film roll according to the present invention can use a commonly known antioxidant as an antioxidant.

In particular, lactone-based, sulfur-based, phenol-based, double bond-based, hindered amine-based, and phosphorus-based compounds can be preferably used.

These antioxidants and the like are added in the range of 0.05 to 20 mass%, preferably 0.1 to 1 mass%, relative to the resin as the main raw material of the film.

These antioxidants and the like can obtain a synergistic effect by combining several different compounds as compared with the use of only one.

For example, a lactone compound, a phosphorus compound, a phenol compound, and a double bond compound are preferably used in combination.

(colorant)

The film roll according to the present invention preferably contains a colorant in order to adjust the color tone within a range that does not impair the effects of the present invention.

The colorant means a dye or pigment, and in the present invention, means a colorant having an effect of changing the color tone of a liquid crystal screen to a cyan color tone, adjustment of a yellow index, and reduction of haze.

As the colorant, various dyes, pigments, anthraquinone dyes, azo dyes, phthalocyanine pigments, and the like are effective.

(ultraviolet absorber)

The film roll according to the present invention can be used also on the visible side and the backlight side of a polarizing plate, and therefore may contain an ultraviolet absorber in order to impart an ultraviolet absorbing function.

The ultraviolet absorber is not particularly limited, and examples thereof include ultraviolet absorbers such as benzotriazole-based, 2-hydroxybenzophenone-based, and phenyl salicylate-based.

Examples thereof include triazoles such as 2- (5-methyl-2-hydroxyphenyl) benzotriazole, 2- [ 2-hydroxy-3, 5-bis (. Alpha.,. Alpha. -dimethylbenzyl) phenyl ] -2H-benzotriazole, 2- (3, 5-di-t-butyl-2-hydroxyphenyl) benzotriazole, and benzophenones such as 2-hydroxy-4-methoxybenzophenone, 2-hydroxy-4-octoxybenzophenone and 2,2' -dihydroxy-4-methoxybenzophenone.

The ultraviolet absorber may be used singly or in combination of two or more.

The amount of the ultraviolet absorber to be used varies depending on the type of the ultraviolet absorber, the conditions of use, and the like, and is generally in the range of 0.05 to 10 mass%, preferably 0.1 to 5 mass% relative to the base resin.

(microparticles)

The film roll according to the present invention is preferably added with fine particles imparting slidability to the film roll.

In particular, the fine particles are effective from the viewpoints of improving the slidability of the film surface according to the present invention, improving the slidability at the time of winding, preventing the occurrence of damage and the occurrence of blocking.

The fine particles may be inorganic fine particles or organic fine particles as long as they have heat resistance at the time of melting without impairing the transparency of the obtained film roll, but are more preferably inorganic fine particles.

These fine particles may be used alone or in combination of two or more.

By using particles having different particle diameters and shapes (for example, needle-like and spherical particles) in combination, both transparency and slidability can be achieved at a high level.

Among the compounds constituting the fine particles, silica having excellent transparency (haze) due to the refractive index close to that of the cycloolefin resin, the acrylic resin, and the cellulose ester resin is particularly preferably used.

Specific examples of silica include commercial products having trade names such as AEROSIL 200V, AEROSIL (registered trademark), SYLOPHOBIC 100 (registered trademark) manufactured by Fuji silicon chemical Co., ltd.), nipsi l 220A (registered trademark) and ADMAXING (registered trademark) SO (manufactured by Nippon silicon industry Co., ltd.) and the like, and specific examples of silica include AEROSIL 200V, AEROSIL (registered trademark), R972V, AEROSIL (registered trademark) R972, R974, R812, 200, 300, R202, OX50, TT600, NAX (manufactured by Nippon AEROSIL Co., ltd.), SEAHOSTAR KEP-10, SEAHOSTAR KEP-30 (registered trademark), SEAHOSTAR KEP-50 (manufactured by Nippon catalyst Co., ltd.), SYLOPHOBIC 100 (registered trademark) and the like.

The shape of the particles is not particularly limited, and amorphous, needle-like, flat, spherical, or the like can be used, and in particular, if spherical particles are used, the transparency of the resulting film roll is good, and thus it is preferable.

Since the particle size is close to the wavelength of visible light, light is scattered and transparency is poor, the particle size is preferably smaller than the wavelength of visible light, and more preferably 1/2 or less of the wavelength of visible light.

If the particle size is too small, the slidability may not be improved, and thus the range of 80 to 180nm is particularly preferable.

The size of the particles means the size of aggregates when the particles are aggregates of 1-order particles.

In the case where the particles are not spherical, the diameter of a circle corresponding to the projected area thereof is meant.

The fine particles are preferably added in the range of 0.05 to 10 mass%, preferably 0.1 to 5 mass%, relative to the base resin.

(use of film)

The film fed from the film roll according to the present invention is preferably used as an optical film, for example, a protective film for a polarizing plate, and can be used for various optical measurement devices, liquid crystal display devices, and display devices such as organic electroluminescent display devices.

Examples

The present invention will be specifically described below with reference to examples, but the present invention is not limited to these examples. In the examples, "part" or "%" is used, and unless otherwise specified, "part by mass" or "% by mass" is indicated.

[ production of film roll ]

(production of film roll No. 1)

A solution casting film forming method is used for film formation.

Film formation step (S1) >)

(preparation of cement)

Synthesis of cyclic polyolefin Polymer (P-1)

100 parts by mass of purified toluene and 100 parts by mass of norbornene carboxylic acid methyl ester were charged into a stirring apparatus.

Subsequently, 25 mmol (relative to the mass of the monomer) of ethyl caproate-Ni dissolved in toluene, 0.225 mol (relative to the mass of the monomer) of tris (pentafluorophenyl) boron, and 0.25 mol (relative to the mass of the monomer) of triethylaluminum dissolved in toluene were charged into a stirring apparatus.

The reaction was stirred at room temperature for 18 hours.

After completion of the reaction, the reaction mixture was poured into excess ethanol to form a polymer precipitate.

The cyclic polyolefin polymer (P-1) obtained by refining the precipitate was dried at 65℃for 24 hours by vacuum drying.

Preparation of cement (D-1)

The following composition 1 was put into a mixing tank, stirred, and after dissolving the components, the mixture was filtered through a filter paper having an average pore size of 34 μm and a sintered metal filter having an average pore size of 10 μm to prepare a dope (D-1).

(composition 1)

150 parts by mass of the cyclic polyolefin polymer (P-1)

380 parts by mass of methylene dichloride

70 parts by mass of methanol

Next, the following (composition 2) containing the cyclic polyolefin solution (cement (D-1)) prepared by the above method was charged into a disperser to prepare a fine particle dispersion (M-1) as an additive.

(composition 2)

100 parts by mass of the cyclic polyolefin solution (D-1) and 0.75 part by mass of the fine particle dispersion (M-1) were mixed to prepare a dope (cycloolefin resin COP1 as a resin composition) for film formation.

(casting of cement)

The prepared dope for film formation (cycloolefin resin COP1 of the resin composition) was fed to a casting die by a pressurized quantitative gear pump using a pipe, was cast from the casting die at a casting position on a support made of an endless-moving rotary-driven stainless steel endless belt using a film-forming line to a width of 1800mm, was heated on the support until the dope had self-supporting property, and was dried by evaporating the solvent until the cast film could be peeled off from the support using a peeling roller, to thereby form a film.

The conditions in the casting of the dope described above are as follows.

Condition(s)

The length of the piping from the pump to the casting die was set to 60m, and the gear ratio of the gear pump for slurry feeding was adjusted so that the rotation speed of the pump was set to 20rpm.

The gap of the width of the slit for discharging the dope was adjusted by using the hot bolts of the casting die so that the film thickness deviation immediately after the discharge was 1.5% with respect to the whole casting film, and the initial discharge film thickness of the casting film was controlled.

The film was formed by drying until the residual solvent amount of the casting film on the tape became 200 mass%, and after forming a coating film on the surface layer, a warm air having a wind speed of 16 m/sec (40 ℃) was sprayed to planarize the protrusions.

(peeling of film)

After the film is formed, the film is peeled off from the support by the peeling roller in a state of having self-supporting property.

(shrinkage in film plane)

The film was subjected to a high temperature treatment in a state where the width of the film was not maintained, and the density of the film was increased, whereby the film was shrunk at a shrinkage rate of 7% in the width direction.

(drying of film)

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

The residual solvent content of the film was measured by the following method and found to be 5 mass% or less.

(determination of residual solvent amount)

As for the amount of residual solvent, mass analysis was performed using gas chromatography as follows.

That is, a membrane at an arbitrary place is used to prevent evaporation of the solvent remaining in the membrane, and thus, the placement of the tap in the vial is promptly ensured.

Next, a needle was inserted into the vial, and mass analysis was performed using gas chromatography (manufactured by agilent technologies).

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

Residual solvent amount (% by mass) = { (M-N)/N } ×100

In the above formula, M is the mass (g) of the sample taken at any time during or after the production of the casting film or film, and N is the mass (g) of the sample after heating at 115℃for 1 hour.

Protrusion adjusting step (S2) >)

(stretching of film)

Then, the film is transported in a tenter stretching apparatus, and the film is stretched in the transverse direction while locally heating the film.

(local heating means)

As the local heating means, an Infrared (IR) heater is used.

The positions of the heat source portions of the infrared heaters on the film were located 75mm apart from the film surface.

The heating width was 150mm (when the intensity immediately below the infrared heater was 1, the intensity was 0.2 heating width).

Each heat source of the infrared heater is set to be 180-350 ℃ under the rated 750W.

(Infrared Heater array and Heat Source portion are spaced apart)

As shown in fig. 6B, the infrared heaters were arranged in 2 rows in the longitudinal direction, and the heat source portions of the infrared heaters were arranged at intervals of 30mm.

(connecting the Heat source portion E) _A And E is _B Is flat relative to the straight line in the length directionAverage inclination angle theta _E ′)

To be arranged with each heat source part E _A And E is _B Average inclination angle θ of straight line formed by connecting straight line and longitudinal direction _E The infrared heater was set so as to be at 5.7 °.

(heat ratio (B/A) of heat A at the center of an Infrared (IR) heater to average value B of heat at the end of the IR heater)

The heat ratio (B/A) of the heat A at the center of the Infrared (IR) heater to the average value B of the heat at the ends of the Infrared (IR) heater was set to 0.2.

In this case, the film thickness profile of the target film in the width direction was measured using an on-line retardation/film thickness measuring device RE-200L 2T-rth+film thickness (manufactured by large-scale electronics (ltd)), the set temperature of each infrared heater was calculated on a computer from the difference between the film thickness profile and the target film thickness profile, the set temperature of each heat source was outputted via PLC KV-8000 (manufactured by KEYENCE (ltd)), and the protrusion was adjusted, and the film thickness was automatically repeated and automatically adjusted.

(maximum height difference (P-V) of length average film thickness at each width position)

Simultaneously with the above-described operation, the maximum height difference (P-V) of the length average film thickness at each width position was controlled so as to be the value of table I (film thickness control was performed by the above-described operation, and the measurement method will be described later).

< finishing Process (S3) >)

Both ends of the stretched film in the width direction are cut (trimmed).

(vibration presence or absence)

In addition, during trimming, the film is not vibrated.

(presence or absence of knurling)

Then, the film was not subjected to knurling.

< winding Process (S4) >)

The film described above was wound up.

The initial tension was 50N, the taper 70% and the corner 25%.

The film was rolled to a width of 2000mm and a roll length of 3900 m.

The linear speed of the transport film was set to 60 m/min.

The film roll No.1 was produced by the above steps.

(confirmation of surface Properties of film relating to the convex portion)

Immediately before the winding step after trimming, the number of protrusions and the height of the protrusions were measured as film properties related to the protrusions, and the continuity of the protrusions was confirmed.

The absolute value of the inclination angle of the substantially straight line with respect to the longitudinal direction of the film surface was measured.

Hereinafter, a method of confirming continuity is shown.

Method for confirming continuity

Specifically, the data measured by the on-line retardation/film thickness measuring device RE-200L2T-Rth+ film thickness (manufactured by Otsuka electronics Co., ltd.) was expressed on a computer in the form of a heat map (horizontal axis: film width position, vertical axis: film length position, depth: film thickness value), and the continuity of the convex was confirmed.

Fig. 14 shows an example of a heat map for actual verification.

Fig. 14 is an example of an actual heat map corresponding to the continuity of the convex portion in fig. 4A, and is an example of a representation corresponding to a "straight line" in table I.

(production of film rolls No. 2-4)

Film rolls No.2 to 4 were produced in the same manner as film roll No.1 except that the maximum height difference (P-V) of the length average film thickness at each width position was controlled to be the value of Table I in < projection preparation step (S2) & gt.

(production of film roll No. 5)

A solution casting film forming method is used for film formation.

The same procedure as in film roll No.1 was carried out in < film formation step (S1) > and < projection preparation step (S2) > respectively.

< finishing Process (S3) >)

Both ends of the stretched film in the width direction are cut (trimmed).

(vibration presence or absence)

In addition, during trimming, the film is not vibrated.

(presence or absence of knurling)

Then, the film was subjected to knurling with a height of 1 μm.

Details thereof are shown below.

And irradiating the film after the finishing step (S3) with laser to form knurled parts.

The knurled width of the two ends of the film was 15mm from the film ends.

The linear speed of the transport film was set to 60 m/min.

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

The irradiation of the film with the laser beam was performed by reflecting the collimated beam emitted from the carbon dioxide laser device by a 2-piece galvanometer mirror, and collecting the beam on the surface of the conveyed film via an fθ lens (focal distance 200 mm).

By controlling the angle of the galvanometer mirror, the light collecting position is moved in the film plane direction, thereby controlling the trajectory of irradiation of the laser light on the film surface.

Atmospheric pressure plasma treatment process: surface modification treatment

The spring day electric mechanism AGP-500 was provided on the back side of the knurled section of the optical film, and irradiated with 0.5kW.

The probe to emit atmospheric pressure plasma was carried out at a distance of 5mm from the film.

The atmospheric pressure plasma is irradiated to the back surface side of the film opposite to the knurling part, and the setting position is set so that the width of 110% of the knurling width can be irradiated.

< winding Process (S4) >)

The film described above was wound up.

The initial tension was 50N, 70% taper, and 25% corner.

The film was rolled to a width of 2000mm and a roll length of 3900 m.

The linear speed of the transport film was set to 60 m/min.

The film roll No.5 was produced by the above steps.

(production of film roll No. 6)

Film roll No.6 was produced by the same procedure as film roll No.5, except that Triacetylcellulose (TAC) was used as the resin composition in place of COP1 in the preparation of the dope < film formation step (S1) > and knurling was performed to a film of 2 μm in the < finishing step (S3) >.

(production of film roll No. 7)

A film roll No.7 was produced in the same manner as in film roll No.5 except that the heat ratio (B/A) of the heat A at the center of the Infrared (IR) heater to the average value B of the heat at the ends of the Infrared (IR) heater was 0.6 in the < protrusion preparation step (S2) > to prepare a film roll No.7.

(production of film roll No. 8)

Film roll No.8 was produced in the same manner as film roll No.5 except that the heat ratio (B/A) of the heat A at the center of the Infrared (IR) heater to the average value B of the heat at the ends of the Infrared (IR) heater was set to 0.1 in the < projection preparation step (S2) & gt.

(production of film roll No. 9)

In the < projection preparation step (S2) > the infrared heaters were arranged in 5 rows in the longitudinal direction as shown in FIG. 6C, and the heat source portion arrangement intervals of the respective infrared heaters were set to be 10mm in pitch; to connect the arranged heat source units E _A And E is _B The infrared heater is set in such a manner that the average inclination angle of the straight line formed by the straight line and the length direction is 2.0 degrees; film roll No.9 was produced in the same manner as film roll No.5 except that the heat ratio (B/a) of the heat a in the central portion of the Infrared (IR) heater to the average value B of the heat at the end portions of the Infrared (IR) heater was set to 0.1.

(production of film roll No. 10)

Film roll No.10 was produced in the same manner as film roll No.5 except that the heat ratio (B/A) of the heat A at the center of the Infrared (IR) heater to the average value B of the heat at the ends of the Infrared (IR) heater was set to 0.9 in the < protrusion preparation step (S2) > for the protrusion preparation step.

(production of film rolls No. 11-15)

In the < projection preparation step (S2) > the infrared heaters were arranged in 1 row in the longitudinal direction as shown in FIG. 6A, and the heat source portions of the infrared heaters were arranged at a pitch of 125mm; each heat source E to be disposed _A And E is _B The average inclination angle of the straight line formed by the connecting straight line and the length direction is not calculated because the infrared heaters are arranged in 1 column in the length direction; the heat ratio (B/A) of the heat A at the central part of the Infrared (IR) heater to the average value B of the heat at the end part of the Infrared (IR) heater was set to 0.9; film rolls No.11 to 15 were produced in the same manner as film roll No.5 except that the absolute value of the inclination angle of the substantially straight line with respect to the longitudinal direction of the film surface was set to the value described in table I in (confirmation of the surface characteristics of the film with respect to the convex portions).

(production of film roll No. 16)

A film roll No.16 was produced in the same manner as in the film roll No.11 except that the continuity of the convex portion was adjusted to draw a locus having a curve of curvature varying at a substantially constant rate of change in the surface characteristics of the film (confirmation of the surface characteristics of the film on the convex portion).

Further, by adjusting the continuity of the convex portion to draw a trajectory having a curve of curvature varying at a substantially constant rate of change, the absolute value of the inclination angle of the substantially straight line with respect to the longitudinal direction of the film surface is not calculated.

(production of film rolls No.17 and 18)

Vibration was performed at a magnitude of 100mm in < finishing step (S3) > to give a vibration; film rolls No.17 and 18 were produced in the same manner as film roll No.16 except that the height of the convex portion was adjusted so as to be the value described in table I in (confirmation of the surface characteristics of the film concerning the convex portion).

(production of film rolls No.19 and 20)

Vibration was performed at a magnitude of 100mm in < finishing step (S3) > to give a vibration; film rolls No.19 and 20 were produced in the same manner as film roll No.16 except that the number of protrusions was adjusted so as to be the values described in table I in the (confirmation of the surface characteristics of the film concerning the protrusions).

(production of film roll No. 21)

A film roll No.21 was produced in the same manner as in film roll No.16 except that vibration was applied at a magnitude of 100mm in < finishing step (S3) > to produce a film.

(production of film roll No. 22)

A step of heating locally by hot air in the step of producing the convex portion (S2); a film roll No.22 was produced in the same manner as in film roll No.16 except that vibration was applied at a magnitude of 100mm in the < finishing step (S3) > step.

(production of film roll No. 23)

A melt casting film forming method is used for film formation.

Film formation step (S1) >)

(melt extrusion of resin)

A resin (cycloolefin resin COP2 of a resin composition) was produced in the same manner as in film roll No.1, and the granulated pellets and additives (fine particles (AEROSIL 812: manufactured by AEROSIL Co., ltd., primary average particle diameter: 7nm, apparent specific gravity: 50 g/L)) were fed to an extruder, melted in the extruder, and extruded from a casting die into a film form on a casting drum by means of a pressurized quantitative gear pump.

(casting and Molding of molten resin/pellet)

In the extrusion step, the length of the pipe from the pump to the casting die was set to 60m, and the gear ratio of the gear pump for feeding the liquid was adjusted so that the rotation speed of the pump was set to 20rpm.

The gap of the width of the slit for discharging the dope was adjusted by using the hot bolts of the casting die, and the film thickness deviation immediately after the discharge was adjusted to 1.5% with respect to the whole casting film, so that the initial discharge film thickness of the casting film was controlled.

The solution was dried until the residual solvent content of the casting film on the tape became 5 mass%, and after forming a coating film on the surface layer, a warm air of 45 m/sec (40 ℃) was sprayed to planarize the protrusions.

The extruded resin is cooled using a cooling drum to form a film.

Protrusion preparation step (S2) >)

(stretching of film)

Then, the film is transported in a tenter stretching apparatus, and the film is stretched in the transverse direction while being locally heated.

(local heating means)

As the local heating means, an Infrared (IR) heater is used.

The heating width was 150mm (the heating width was 0.2 when the intensity immediately below the infrared heater was 1).

(Infrared Heater array and Heat Source portion are spaced apart)

As shown in fig. 6A, the infrared heaters were arranged in 1 row in the longitudinal direction, and the heat source portions of the infrared heaters were arranged at a pitch of 125mm.

(connecting the Heat source portion E) _A And E is _B Average inclination angle θ of the straight line with respect to the longitudinal direction _E ′)

Each heat source part E to be arranged _A And E is _B The average inclination angle of the straight line connecting the straight line and the longitudinal direction is not calculated since the infrared heaters are arranged in 1 line in the longitudinal direction.

The heat ratio (B/A) of the heat A at the center of the Infrared (IR) heater to the average value B of the heat at the ends of the Infrared (IR) heater was set to 0.9.

< finishing Process (S3) >)

Both ends of the stretched film in the width direction are cut (trimmed).

(vibration presence or absence)

In trimming, the film was vibrated at a width of 100 mm.

(presence or absence of knurling)

Then, the film was subjected to knurling with a height of 1 μm.

Further, knurling was performed in the same manner as in film roll No. 5.

< winding Process (S4) >)

The film described above was wound up.

The initial tension was 50N, the taper 70% and the corner 25%.

The film was rolled to a width of 2000mm and a roll length of 3900 m.

The linear speed of the transport film was set to 60 m/min.

The film roll No.23 was produced by the above steps.

(confirmation of surface Properties of film relating to the convex portion)

As described above, immediately before the winding process after trimming, the number of protrusions and the height of the protrusions were measured as film properties related to the protrusions, and the continuity of the protrusions was confirmed.

(production of film roll No. 24-27)

In the step of < protruding part preparation (S2) > the intermediate infrared heater is as shown in the figure6A, 1 row in the longitudinal direction, the heat source units of the infrared heaters were arranged at a pitch of 125mm; each heat source part E to be arranged _A And E is _B The average inclination angle of the straight line formed by the connecting straight line and the longitudinal direction is not calculated because the infrared heaters are arranged in 1 column in the longitudinal direction; the heat ratio (B/A) of the heat A at the central part of the Infrared (IR) heater to the average value B of the heat at the end part of the Infrared (IR) heater was set to 0.9; vibration was performed at a magnitude of 100mm in < finishing step (S3) > to give a vibration; film rolls nos. 24 to 27 were produced in the same manner as film roll No.5, except that the number of protrusions, the height of the protrusions, the continuity of the protrusions, the absolute value of the inclination angle of the substantially straight line with respect to the longitudinal direction of the film surface, and the maximum height difference (P-V) between the substantially straight-line inclination angle of the protrusions and the length average film thickness at each width position were set to the values described in table I in (confirmation of the surface characteristics of the film with respect to the protrusions).

(production of film roll No. 28)

No (local heating means) of < protrusion preparation step (S2) > is used; film roll No.28 was produced in the same manner as film roll No.24 except that the values of the surface properties of the film with respect to the protrusions were controlled as shown in table I.

Examples and comparative examples

The following evaluations were performed using film roll nos. 1 to 23 as examples and film roll nos. 24 to 28 as comparative examples.

The measured values and evaluations relating to film rolls nos. 1 to 28 are shown in table I.

TABLE I

[ various assays and evaluations ]

The following shows a method for measuring and calculating the characteristics such as the outer diameter of the various film rolls and an evaluation method.

A. Maximum height difference (P-V) of length average film thickness at each width position

(measurement method)

The measurement of the maximum height difference (P-V) of the length average film thickness at each width position of the film thickness values measured in the order of steps 1 to 3 described below in the direction inclined with respect to the film width direction was performed by measuring 3 ten thousand film thicknesses (manufactured by Otsuka electronics) using an in-line retardation film thickness measuring device RE-200L 2T-Rth+.

The measured timing was immediately before the winding step at room temperature in all the steps of the solution casting film forming method and the melt casting film forming method.

At this time, the traverse speed was 100 mm/sec.

The data used in step 3 to calculate the length-average film thickness value was measured at 3 ten thousand points.

Step 1:

Step 2:

after the completion of the step 1, the total distance between the moving positions in the longitudinal direction was 1000m, which was measured in the same manner as in the step 1.

Step 3:

based on the large amount of film thickness data obtained in the steps 1 and 2, the film thickness values at the same width position are averaged to obtain the length average film thickness value at each width position. From which the difference in height (P-V) between the maximum value and the minimum value is calculated.

B. Orientation angle

(measurement method)

The optical value (orientation angle) of the film was measured at the film end in the width direction (for example, at a position 15mm inward from the width-most end) at the film length direction with a sampling period of 50 milliseconds using an online retardation/film thickness measuring apparatus RE-200L 2T-rth+film thickness (manufactured by the tsuka electronics).

The measurement position (the installation position of the measurement device) was set so that the film was 100m long from the film end (the winding position).

Then, the longitudinal orientation angle fluctuation was evaluated based on the following evaluation criteria.

Here, the angle of the slow axis of the molecules in the film with respect to the film longitudinal direction (film forming direction, transport direction) is defined as the orientation angle θ.

Here, "change in orientation angle" refers to the standard deviation (σ) of the measured orientation angle.

(evaluation criteria)

And (3) the following materials: the orientation angle variation in the longitudinal direction 3000m is in the range of 0 to 0.10 °.

O: the variation of the orientation angle in the longitudinal direction 3000m is larger than 0.10 DEG and less than 0.12 deg.

X: the variation of the orientation angle in the longitudinal direction 3000m is larger than 0.12 °.

Further, for example, "the orientation angle fluctuation value in the longitudinal direction 3000m is in the range of 0 to 0.10 °, means that the fluctuation range of all data of the orientation angle θ is in the range of 0 to 0.10 ° when the orientation angle θ at the film width end portion is measured at a period of 50 milliseconds in the longitudinal direction in 3000m of the film length direction (in this case, the measurement points of the orientation angle at the width end portion are arranged at a pitch corresponding to the period of 50 milliseconds in the film length direction).

Therefore, the closer the evaluation is, the narrower the range of variation of the orientation angle θ (the smaller the variation of the value of the orientation angle θ), the smaller the deviation of the orientation angle in the longitudinal direction.

C. Chain evaluation

(evaluation method)

After the films obtained in examples and comparative examples were wound up, the films were allowed to stand in an atmosphere of 23℃and 55% humidity for 15 minutes, and whether or not chain-like deformation was present on the outermost layer of the film roll was visually confirmed.

Then, the chain deformation was evaluated based on the following evaluation criteria.

(evaluation criteria)

Good: no deformation was confirmed.

The method comprises the following steps: although some deformation was confirmed, there was no problem in practical use because of elastic deformation.

Poor: more than 1 chain-like deformation which is practically problematic was confirmed.

D. Scratch evaluation

(evaluation method)

The appearance of scratches on the films of the film rolls obtained in examples and the film rolls obtained in comparative examples was visually observed and evaluated according to the following evaluation criteria.

Even when no winding displacement was found, scratch was slightly observed in some cases.

This is caused by film friction (mutual friction) in the film roll, and the scratch in this case corresponds to "Σ" in the following evaluation.

(evaluation criteria)

And (3) the following materials: almost no scratches were found on the film.

O: scratch was found slightly on the film, but there was no problem on the article.

X: numerous scratches are found on the film and are problematic in the article.

(summary)

From the above, it is clear that the examples are excellent in combination by comparing various performance evaluations of the examples and the comparative examples in table I.

Industrial applicability

A method for manufacturing a film roll suitable for manufacturing a wide film by processing the film and a projection adjusting system used for manufacturing the film roll, which can suppress the change of an orientation angle to be small without generating a roll failure, can be provided.

Description of the reference numerals

1. 1a stirring device (stirring tank)

2. Casting die head

3. Support (Ring belt, rotary drum)

3a, 3b roller

4. Stripping roller

5. Cast film

6. Drying device

7. Stretching device (tenter stretching device, inclined stretching device)

8. Cutting part

10. Cutting part

11. Drying device

12. Cutting part

13. Coiling device

14. Extrusion machine

15. Casting die head

16. Casting drum, support body

16a touch roller

17. Cooling drum

19. Stretching device (tenter stretching device)

20. Cutting part

23. Coiling device

30. Film roll

31. Film and method for producing the same

32. Roller

33. Touch roller

40. Stretching device (tenter stretching device)

42. Clamp

46. Cover for vehicle

48. Endless chain

50. Driving sprocket

52. Driven sprocket

54. Rail track

56. Open member

80. Temperature distribution sensor

101. Nozzle fixing portion

102. Nozzle

103. Cast film

104. End nozzle

105. Central nozzle

106. Clamp cover

Part of the end of the film roll

Part of the concave-convex shape of the B knurl

C width-directional adhesive part

D length direction adhesive part

F film

H _A 、H _B Wide width of

Q Infrared (IR) heater

height of h protrusion

E _A 、E _B Heat source unit

Inclination angle of θ' to a substantially straight line in the longitudinal direction of the film surface

θ _E ' Heat Source section E _A And E is _B Average inclination angle of straight line of connection with respect to straight line of length direction

The heat source parts of the infrared heaters P1, P2 and P3 are provided with intervals

Claims

1. A method for producing a film roll by a solution or melt casting method, comprising: a film forming step, a protrusion adjusting step in the width direction of the film surface, a trimming step of both end portions of the film, and a winding step of the film trimmed by the trimming step, wherein the protrusion adjusting step is a step of adjusting the number, height, and position of the protrusions so that the protrusions continuously move in the length direction of the film surface by applying local heating to the film so that the number of protrusions is in the range of 1 to 10 per 1m in the width direction, and so that the height of the protrusions is in the range of 0.05 to 0.50 μm.

3. The method according to claim 1 or 2, wherein in the protrusion adjusting step, the position of the protrusion is adjusted to be aligned on a substantially straight line in the longitudinal direction of the film surface by locally heating the film, and an absolute value of an inclination angle of the substantially straight line with respect to the longitudinal direction of the film surface is in a range of 0.01 to 0.6 °.

4. The method for producing a film roll according to any one of claims 1 to 3, wherein the local heating is performed by using infrared heaters arranged in the width direction and the length direction of the film, heat source units of the infrared heaters are arranged at intervals of 10 to 100mm in the width direction of the film, and the heat source units are arranged at positions different from the width positions in the length direction of the film, and each of the arranged heat source units E is arranged _A And E is _B Average inclination angle θ of straight lines connecting _E ' in the range of 2 to 45 DEG relative to the longitudinal direction.

5. The method for producing a film roll according to any one of claims 1 to 4, wherein an average value B of heat A at a central portion and heat B at an end portion of the infrared heater satisfies the following formula (1),

formula (1): 0.2 < (B/A) < 0.6.

6. The method of producing a film roll according to any one of claims 1 to 5, wherein after the finishing process, no knurling process is performed on the film.

7. The method for producing a film roll according to any one of claims 1 to 6, wherein the maximum height difference (P-V) of the length average film thickness at each width position of the film thickness values measured in the order of the following steps 1 to 3 in a direction inclined with respect to the width direction of the film is in the range of 0.02 to 0.40 μm,

step 1:

after the film thickness was measured at an arbitrary position at the end of the film, the film thickness was measured at a position shifted 10mm in the width direction and 30mm in the length direction from the arbitrary position at each measurement, the width position, the length position, and the film thickness value were recorded, and repeated until the other end of the film was reached,

step 2:

Step 3: