TW201412496A - Method for producing film roll - Google Patents

Abstract

The present invention relates to a method for producing a film roll with good appearance without using oscillations means, there is provided with a method for manufacturing the film roll, characterized by comprising: a film forming step (A) which extrudes thermoplastic resin from an adjusting means having a lip gap, and moves the film while making the film; a thickness adjusting step (B) for adjusting the film thickness during the transitional movement of the film; a step of rolling the film into a roll shape (C). In step (B), the film thickness is adjusted by repeating the following steps of (a) to (c): (a) a step of measuring the film thickness at specific intervals in the width direction of the film to produce respective thickness profiles; (b) a step of producing the measurement thickness profile based one or more of the respective thickness profiles; (c) a step of adjusting the lip gap based on the measurement thickness profile and the preset thickness profile. Also, the film is subjected to thickness adjustment again in a manner of meeting the following conditions respectively: R1 ≤ 2.0 μm, σ1 ≤ 0.5 μm, RAV ≤ 1.0 μm, and σAV ≤ 0.2 μm, where R1 denoted as the amplitude of the film thickness in a measurement thickness profile, σ1 as standard deviation of the film thickness in a measurement thickness profile, RAV as amplitude of the film thickness in the cumulative average profiles, and σAV as standard deviation of the film thickness in the cumulative average profiles.

Description

Film coil manufacturing method

The present invention relates to a method for producing a film web, and more particularly to a method for producing a film web formed by winding a film made of a thermoplastic resin into a roll.

A film made of a thermoplastic resin such as polyester, polypropylene, polycarbonate, or polymethyl methacrylate (PMMA), for example, as a light diffusing film in a flat panel display such as a liquid crystal display device or a plasma display device Or a protective film or the like for protecting the surface of the constituent member of the flat display.

Further, in the liquid crystal panel of the liquid crystal display device, for example, a polarizing plate is disposed, and such a polarizing plate is formed on both surfaces of the polarizer, and a protective film composed of the above thermoplastic resin is laminated, and An anti-glare layer, a hard coat layer, or the like is further provided on at least one surface of the protective film.

Further, for example, in the polarizing plate having the above configuration, when the protective film composed of the thermoplastic resin has uneven thickness (that is, the thickness is not uniform), such a protective film is easily peeled off when placed in When cracking in high temperature and low temperature environments, cracks are likely to occur. The value of the goods is obviously damaged. Therefore, in the manufacturing process of such a film composed of a thermoplastic resin, it is required to have a film thickness in the width direction of the film orthogonal to the longitudinal direction of the film (or the traveling direction or the conveying direction of the film in the production line). The distribution is set within a specific range. For example, it is desirable to control the film thickness in a manner that the film thickness is uniform over the full width of the film. The adjustment of the width direction of the film thickness is carried out by a thickness adjusting means provided on a lip having a specific width of the mold, and the above mold is used for extrusion molding a molten thermoplastic resin, in general, It is a bolt which can adjust the slit-like gap of the lip through which the molten polymer passes, or a means such as a bolt and a heater which can heat the bolt (for example, an actuator of a hot bolt type, etc.). Further, the gap between the lips can be independently adjusted in each section by using bolts each provided in a plurality of sections provided at a specific interval in the width direction of the lip. Moreover, the adjustment of the gap between such a lip is also automated.

The thickness in the width direction of the film which is adjusted by using such a thickness adjustment means is generally measured by a thickness measuring device while the film is wound into a roll shape, and the measured value is fed back to the above-mentioned adjusting means, and then Further, the adjustment of the uniformity of the thickness in the width direction of the film is repeated, that is, so-called feedback control is performed.

In the method for adjusting the thickness of the film based on the thickness measurement, the thickness of the film can be scanned from one end to the other at least once by using the adjustment method in the width direction of the film. Measuring the thickness profile made by measuring the film thickness at the end of one side, and performing thickness control in the width direction of the film by the above feedback control Homogenization, but at the surface appearance of the final film web product, to create a convex portion called the gauge band along the longitudinal direction (or winding direction) of the film, or called a pyramid ( (pyramid) has many bad situations.

Here, the "burst" is also referred to as a kelp roll, a piston ring, or the like, and refers to a band-shaped defect (protrusion) which is generated in a winding direction in one portion of the film roll when the film is wound into a roll shape. ). This defect is caused by the thickness of the film in the width direction of the film, since only a part of the film having a large thickness is wound on the roll and accumulated in the winding direction. As a result, the ribs are caused by the difference in the winding diameter of the film web.

In addition, the "pyramid" is also called a wrinkle, a polygonal shape, and the like, and is formed in a strip shape in which fine concavities and convexities on the surface of the web are formed in a strip shape.

Both of the defects are in the respective processing works of the post-processing represented by the hard coating treatment, the low-reflection (AR) treatment, the anti-glare (AG) treatment, and the like on the resin film. Any of the above defects in the film web are strongly required to be improved in the quality of the film.

Further, in the thickness adjustment means described above, the feedback control of the adjustment means is performed based on the measurement of the thickness profile, but the target value at the time of the reference is a uniform thickness distribution in the width direction of the film (this is also called the expected thickness profile). ).

Therefore, for example, the thickness of the film in one of the sections of the thickness profile is measured (that is, the thickness of the film in a specific section set in the width direction of the film) When it is larger than the target value, in order to suppress the discharge amount of the molten polymer discharged from the mold corresponding to the section, the adjustment of the gap in which the lip is reduced in the section is performed.

Then, the thickness of the film is adjusted while repeating the same adjustment, and finally a uniform thickness is obtained in the width direction of the film.

However, at this time, the cumulative thickness obtained by adding and averaging the film thicknesses of the portions (or sections) in the measured thickness profile produced during the adjustment of the discharge amount (that is, the cumulative value of the thickness of the longitudinal direction of the film) The average) is still thicker than its target value.

That is, the cumulative thickness of the portion becomes a value on the + side with respect to the target value, and as a result, the cause of defects such as ribs or pyramids cannot be excluded.

As a result, in the conventional thickness adjustment means, since the elements relating to the cumulative thickness of the film are not considered at all, it is necessary to effectively suppress defects such as ribs or pyramids in the film web, and to obtain an appearance. Good film coils have difficulties.

In view of this, in the prior art, there has been proposed a method in which, for example, a relative reciprocating motion (oscillation mechanism) of the axial direction of the core is performed between the film and the core for winding the film at a certain period, A method of winding a film (see Patent Document 1, etc.).

It is a method of temporarily winding a film on an intermediate roll, then winding the film from the intermediate roll, cutting it into a desired width while applying vibration, and winding it into a roll shape to produce a final film roll. Thickness distribution in the width direction of the film before the intermediate roll, predicting the final roll of the film roll The shape and the method of controlling the discharge amount in the mold based on the predicted final roll shape (see Patent Document 2, etc.).

The invention relates to a method for manufacturing a film web which is obtained by winding a film from an intermediate roll of a film, and slitting (cutting) a plurality of specific product widths to produce a product roll, which measures the roll diameter distribution of the width direction of the intermediate roll. A method in which the intermediate roll is moved (oscillated) to the axial direction by the oscillating condition determined by the measured value, and the product coil is produced by striping (see Patent Document 3, etc.).

The method for winding a film belongs to measuring the thickness distribution in the width direction of the stretched film, and according to the measured value, controlling the discharge amount discharged from the mold, while controlling the thickness distribution in the width direction of the film to a specific profile. a method for winding a film into a roll shape, characterized in that: measuring a roll diameter distribution in a width direction of the film roll, predicting a roll shape of the film roll after winding from a roll diameter distribution value, and based on the prediction The value is adjusted to the amount of discharge from the mold, and the roll shape of the film roll is controlled to the target roll shape (see Patent Document 4, etc.).

[Previous Technical Literature] [Patent Document]

[Patent Document 1] Japanese Patent Publication No. 36-22875

[Patent Document 2] Japanese Patent Laid-Open Publication No. 2002-28972

[Patent Document 3] Japanese Patent Laid-Open Publication No. 2002-87690

[Patent Document 4] Japanese Patent Laid-Open Publication No. 2001-30339

However, in the invention described in Patent Document 1, when the film is shaken (oscillated) by the winding portion, the film is not subjected to uniform winding tension, and wrinkles are generated, and the end face of the wound film roll is wound. There is no uniform alignment, and since EPC (Edge Position Control) mechanism or the like is required even in the post-engineering, there are many problems in terms of quality and equipment.

Further, in Patent Document 1, in order to uniformly align the end faces of the coils, slitting (cutting) and oscillation of the width of the product are also performed, but since it is necessary to enlarge the effective width of the wide portion of the shake, it is necessary to produce the film. The scale of the device is set to be large, and there is a big problem in cost.

Further, the inventions described in Patent Documents 2 and 3 are directed to the intermediate roll, that is, the wound appearance on the roll used in the film production process, and are not described in detail, but are related to the final roll product after the oscillation is performed. Winding appearance. As described above, the efficiency decreases as the oscillation is performed, and in this method, since it is additionally required to be retracted (replaced) or slitted from the intermediate roll toward the final product coil, time and labor burden are large. Can't be said to be efficient.

According to the invention of Patent Document 4, since the roll diameter distribution of the actual film web is directly measured, the appearance of the film web can be finished to be good, but the vibration of the winding device at the time of winding the film web or The measurement error caused by the equipment such as the shaft of the take-up shaft is shaken, and the appearance of the winding is damaged. Furthermore, it is also predicted that the measurer due to the additional roll diameter distribution or the newly added soft control for feedback control of the measured roll diameter distribution Body, or wiring connections, etc., cost a lot.

Accordingly, the present invention has an object of providing a film web having a good appearance without using oscillation.

In order to solve the above problems, the inventors of the present invention have intensively studied the results and found a solution formed by the following constitution to complete the present invention.

Therefore, although the present invention provides the following production methods, the present invention is not limited to the following methods.

[1] A method for producing a film web comprising the following items (A) to (C): (A) extruding a thermoplastic resin from a mold having an adjustment means of a lip gap, and moving while moving (B) the process of adjusting the thickness of the film during the migration of the film, repeating the following steps (a) to (c), and adjusting the thickness of the film, a) measuring the thickness of the film in the transition at a specific interval in the width direction of the film orthogonal to the direction of travel of the film, forming a step of individual thickness, and (b) forming the individual thickness profile according to one or more a step of measuring a thickness profile, (c) a step of adjusting a lip gap of the mold according to the measured thickness profile, and a set thickness profile; (C) a process of winding the film into a roll shape, in the project (B) In order to satisfy the following conditions, the thickness of the film is adjusted, R ₁ ≦ 2.0 μm, σ ₁ ≦ 0.5 μm, R _AV ≦ 1.0 μm, and σ _AV ≦ 0.2 μm, where R ₁ is The difference between the maximum value and the minimum value of the film thickness in the measured thickness profile at one time, indicating the measured thickness The amplitude of the surface film thickness, σ ₁ of the system indicates a measure of the thickness profile of film thickness variations, R _AV system 100 represents the consecutive measurement of the thickness profile produced by adding the cumulative average of the average cross-sectional view of the obtained The difference between the maximum value and the minimum value of the film thickness indicates the amplitude of the film thickness in the cumulative average cross section, and σ _AV indicates the standard deviation of the film thickness in the cumulative average cross section].

[2] The production method according to the above [1], wherein, in the step (a), the end portion from one end of the width direction of the film to the other end is measured at a specific interval, or from another The measurement data relating to the thickness of the film obtained from the end of one of the ends to the end of one of the ones is made to have one of the above individual thickness profiles.

[3] The production method according to [1] above, wherein in the step (b), the measured thickness profile is produced based on two or more individual thickness profiles.

[4] The production method according to any one of [1] to [3] wherein the set thickness profile is selected from the group consisting of a desired thickness profile and an inverse symbol profile.

[5] The production method according to [4] above, wherein the set thickness profile is an inverse symbol cross section.

[6] The production method according to [5] above, wherein the inverse sign profile is produced based on the measured thickness profile for each of the measured thickness profiles.

According to the present invention, it is possible to efficiently produce a film web having a good appearance without using oscillation.

1‧‧‧Mold

2‧‧‧Adjustment means

3‧‧‧ casting rolls

3'‧‧‧ casting rolls (or counter rolls)

3"‧‧‧ casting rolls (or cooling rolls)

4‧‧‧ thermoplastic resin film

5‧‧‧ thickness gauge

6‧‧‧ film coil

7‧‧‧Control means

Fig. 1 is a schematic view showing an example of a device used in the production method of the present invention and the production method of the present invention.

Fig. 2 is a schematic view for explaining a cross section of an inverse symbol.

Fig. 3 is a schematic view showing a change in film thickness by adjusting the thickness of the film.

Hereinafter, one embodiment of the method for producing a film web of the present invention will be described in detail with reference to the drawings, and the present invention is not limited to the embodiment.

Fig. 1 is a schematic view showing an example of a device which can be used in the method for producing a film roll of the present invention and the method for producing the film of the present invention.

The apparatus usable in the method for producing a film roll of the present invention has a mold 1 capable of discharging molten thermoplastic resin into a film shape as shown in Fig. 1, and the discharge amount of the thermoplastic resin can be adjusted. Further, the adjusting means 2 for adjusting the thickness of the film made of such a thermoplastic resin can be adjusted; and at least one casting roll which can form a film shape and impart smoothness to the surface and which is cooled can be formed by sandwiching the molten thermoplastic resin. 3 (and 3' and 3"); disposed on the moving path of the thermoplastic resin film 4, the thickness measuring device 5 capable of measuring the thickness in the width direction of the film orthogonal to the traveling direction of the film 4; thermoplastic resin can be used The film 4 is wound into a roll-like reel (not shown); the control means 7 for instructing the adjustment means 2 can be stored by storing the data measured by the thickness measuring device 5 and processing the measurement data.

Using the device constructed as described above, in the system of the present invention In the production method, the thermoplastic resin film 4 formed by melt extrusion molding is wound into a roll shape by a coiler (not shown) to finally form the film web 6.

Further, in the present invention, the thermoplastic resin film 4 is wound into a roll and is referred to as a "film roll".

In the production method of the present invention, as shown in Fig. 1, first, a thermoplastic resin is continuously supplied to an extruder (not shown), and the molten thermoplastic resin is pressed by the mold 1 to form a film. More specifically, the thermoplastic resin is pressed from the slit-like gap of the die lip of the mold 1.

The thermoplastic resin may, for example, be a homopolymer of an ethylenic monomer such as ethylene, propylene, butylene or hexene or a copolymer of two or more kinds of the above-mentioned ethylenic monomers, or more than one type of the above alkene. a polyolefin resin such as a monomer and a copolymer of one or more kinds of polymerizable monomers capable of polymerizing with the above olefinic monomer; polymethacrylate (PMA), polymethyl methacrylate (PMMA) Acrylic resin such as ethylene-ethyl acrylate copolymer; butadiene-styrene copolymer, acrylonitrile-styrene copolymer, polystyrene, styrene-butadiene-styrene copolymer, styrene/ a styrene resin such as an isoprene/styrene copolymer or a styrene-acrylic acid copolymer; a vinyl chloride resin; a fluorinated vinyl resin such as polyvinyl fluoride or polyvinylidene fluoride; and 6-endron, 6,6-Anthracycline resin such as Nylon, 12-Nylon, etc.; ester resin of polyethylene terephthalate or polybutylene terephthalate; polycarbonate resin, polyphenylene ether Resin, polyacetal resin, polyphenylene sulfide resin, polyfluorene resin, heat Plastic amine urethane resins, polyether ether ketone-based resins, polyetherimide resins, Thermoplastic elastomeric resin, bridging resin, etc. In addition, the thermoplastic resin which can be used in the present invention is not limited to the above, and is not particularly limited as long as it can be formed into a film by melt extrusion molding.

The thermoplastic resin may contain an additive such as a suitable rubber particle, a fatty acid ester, a stabilizer, an oxidation inhibitor, an ultraviolet absorber, a flame retardant, or a nonionic surfactant in an optional amount.

The mold 1 is provided with a lip having a slit-like gap for discharging molten resin, and the mold lip is provided with an adjustment means 2 for each specific section in the lip width of the lip.

In the adjustment means 2, it is sufficient to adjust the gap between the lips of the molten resin, and it is also possible to independently adjust the discharge amount of the molten resin discharged from the lip in each of the designated sections, and the mold 1 can be independently adjusted in each section. The discharge amount distribution of the molten resin in the full width direction. As a result, in the present invention, the thickness distribution in the width direction of the thermoplastic resin film 4 (hereinafter, also in the case of the resin film 4 or the film 4 or simply a film) can be adjusted.

The adjustment means 2 is a mechanism that has a gap that can adjust the gap of the lip in a specific direction of the lip width direction of the mold 1, and further has a mechanism that can independently adjust the discharge amount of the molten resin in each section, and does not In particular, for example, a means for adjusting the gap of the lip in the interval by pushing the bolt provided in each section along the width of the lip; by means of a bolt, and being electrically disposed around such a bolt A thermo-bolt type actuator that is constructed by a heater that freely adjusts the amount of heat transfer and that can independently adjust the gap between the lips in each section by utilizing the expansion and contraction of the bolt caused by the heat. Etc. In the present invention, an actuator using a hot bolt method is preferred.

Further, the adjustment means 2 is formed on the entire width of the lip of the mold 1, and is independently provided in each of the specific sections in the width direction of the lip, and the interval of the section is generally 10 to 100 mm, preferably 20 to 60 mm. Therefore, for example, the number of the thickness adjusting means 2 of the mold 1 which is set to have a lip width of 1800 mm is generally 18 to 180, preferably 30 to 90.

As a result, the molten resin extruded from the lip of the mold 1 can be sandwiched between the two casting rolls 3 and 3', as shown in Fig. 1, for example, even if it is in the form of a film. Forming and cooling, and if necessary, the third casting roll 3" can be used to cool and solidify (and the casting roll 3' is also referred to as a counter roll, and the casting roll 3" is also referred to as a cooling roll) .

Further, in the present embodiment, a three-roll method in which a film can be formed by using three rolls and cooled and solidified is exemplified, but even if one of the casting rolls is one, even two or four or more plural numbers may be used. Roots can also. Further, in the first drawing, the casting rolls are arranged in a state of being arranged in a row, but the arrangement thereof is not particularly limited, and for example, even in an I-shape or an L-shape and an inverse L-shape arranged in a vertical column, It may be arranged in a state of a zigzag, an inverse zigzag, or a tilted configuration.

The surface of the casting roll can be applied to the surface of the film, for example, by applying a plating treatment, and then even a mirror roll which is mirror-finished by polishing finishing. Furthermore, even if a processing or treatment that imparts a lens shape that imparts a braided shape, a serpentine shape, or a columnar shape is applied can.

In terms of the structure of the casting roll, even a roller (or a cutting roll) having a highly rigid drilling structure which is formed by cutting a cylindrical metal can be disposed even with a thin metal disposed around it. The elastic structure of the seamless tube (so-called elastic roller) may be formed. Further, the casting roll may be formed of a rubber material such as polyfluorene or fluorine. In general, the temperature of the heat medium for circulating cooling inside the roll can be appropriately changed in accordance with the thermal characteristics of the thermoplastic resin.

In this way, the molten resin is brought into contact with the surface of the roll and passed over the roll, suitably formed and cooled and solidified, thereby becoming the resin film 4, and finally passes through any of a plurality of carrying rolls and/or rotating rolls as needed, and finally borrows It is wound into a roll shape by a coiler to form a film web 6.

The resin film 4 is passed through a pair of thickness measuring devices 5 disposed above and below the film, and is subjected to a foreign matter inspection machine (not shown) and protected, even when being wound into a roll shape to form the film roll 6. A film laminating machine (not shown), an end parting machine (not shown), or the like may be used. These machines are appropriately selected in advance in accordance with the performance required for the resin film, and generally have a thickness measuring device 5, a foreign matter inspection machine, and an end portion machine.

Taking the thickness measuring device 5, for example, the two measuring probes are arranged to contact the two sides (up and down) of the film, and the contact type measuring device for measuring the thickness of the film by measuring the distance between the measuring probes; A non-contact type measuring device or the like for measuring the thickness of a film in a non-contact manner using radiation or the like, wherein in the present invention, from the viewpoint of preventing damage to the film, etc. It is better to use a non-contact measuring device. Further, even in the non-contact type measuring instrument, it is preferable to use a radiation transmission type thickness measuring device or the like from the viewpoint of monitoring the measurement accuracy on the line or the like.

The measurement of the thickness of the film is performed by the thickness measuring device 5 during the scanning of the film 4 from the end of one side of the film 4 toward the other end by the thickness measuring device 5 (scanning). Film thickness, followed by continuous scanning (scanning) from the other end of the film 4 toward the other end to measure the film thickness, and the film thickness measured at a specific measurement interval in the width direction of the film The measured values are all sent to the control means 7.

As described above, the thickness measuring device 5 measures the thickness of the resin film 4 which is moved on the line while scanning in the width direction of the film, so that the position of the film thickness actually measured by the thickness measuring device 5 is shifted with respect to the film. The direction and the width direction of the film are oblique directions which can be shifted from the speed on the line of the resin film 4 (hereinafter, referred to as line speed), and the film thickness in the film width direction of the thickness measuring device 5 is scanned. The scanning speed at which the thickness is measured is calculated and determined.

The thickness measurement interval in the width direction of the film can correspond to a specific interval in the section of the mold lip 1 for arranging the adjustment means 2, and is generally 0.1 to 30 mm, for example, the full width of the film is At 1450 mm, the interval between the intervals is set to, for example, 10 mm. Further, in the present invention, the thickness of the film may be measured in more detail at a specific measurement interval even if a plurality of measurement points are provided in each section. If the measurement interval at this time is within the range of 0.1 to 30 mm, it is not special. Do not limit.

The line speed is generally 10~100m/min. The measuring device 5 measures the thickness of the film on one side in the width direction of the film, and generally scans at a speed of 0.5 to 3 m/min.

Then, in the present invention, in the above-mentioned work (B), the measurement is performed by the measuring device 5 in the course of the migration of the resin film 4 by repeating the steps (a), (b) and (c) which will be described in detail below. The measurement data relating to the thickness of the film is given to each of the adjustment means 2 from the control means 7, and the thickness of the resin film 4 can be adjusted by independently adjusting the gap of the lip in each section.

Step (a): measuring the thickness of the resin film 4 in the transition at a specific interval in the width direction of the resin film 4 orthogonal to the traveling direction of the resin film 4, and forming a step of individual thickness, step (b): One or more of the above individual thickness profiles, a step of measuring the thickness profile, and a step (c): the step of adjusting the lip gap of the mold 1 according to the measured thickness profile and the arbitrarily selected thickness profile; In a), for example, in the migration of the film 4, in the width direction of the film orthogonal to the traveling direction of the film 4, by one minute at a specific interval in the width direction of the film (that is, from the end to the end) The thickness of the film from one end of the film to the other end or from the other end to the end of one of the films is measured at each measurement point. Measurement data relating to film thickness (including the measurement of film thickness at each measurement point) The information of the information, including the information of the position of each measuring point and the information of the film thickness measurement at the measuring point, is sent to the control means 7, and each such measurement data is sent to the control means 7, In the control means 7, the "individual thickness profile" is created based on the measurement data of a certain measurement point within the effective width of the product to be used as the product.

Therefore, the "individual thickness profile" in the present invention includes information on the measurement of the film thickness at each measurement point of the film in the width direction of the film at a specific interval, which means that the film is divided by the width direction of the film. Scanning and measuring information on the positional information of each measurement point within the effective width of the product obtained and the measurement of the film thickness at the measurement point.

Further, in the above embodiment, although the individual thickness profile is produced based on the measurement data of the effective width of the product used as the film for the product, in the present invention, the individual thickness profile is not limited to the individual thus produced. In the thickness profile, an individual thickness profile is formed even for all measurement data obtained from one end of the film in the width direction to the other end or from the other end to the end of one of the scans. Also.

Therefore, in the present invention, it is characterized in that the thickness of the film is measured in accordance with the end portion from one end of the film width direction to the other end portion at a specific interval, or from the end portion of the other side to one end portion. That is, the scanning of the width direction of the film is measured once and all the measurement data relating to the film thickness, and an individual thickness profile is made at the full width of the film or the effective width of the product.

Moreover, in the present invention, the film product is effectively widened to When the film roll is manufactured, it can be arbitrarily set in advance, and is generally 50 to 95%, preferably 60 to 90%, and more preferably 65 to 85%, with respect to the full width of the film. In the film within the above range, the film thickness in the width direction has almost no deviation. Further, in the present invention, the "deviation" of the thickness of the resin film 4 means that the thickness of the resin film 4 becomes larger or smaller with respect to the desired thickness of the resin film 4, meaning that the thickness of the film is not uniform.

In addition, before the resin film 4 is wound into a film roll, the width of the wound resin film 4 is as wide as the product, and the end portion in the width direction of the film is trimmed by a slitter or the like ( Even if it is the end of both sides, the end of the unilateral portion can be cut efficiently, and the portion of the resin film 4 that is effectively widened outside the thickness of the product (for example, beaded beads, etc.) can be efficiently cut. In the meantime, a film roll having a good appearance in which the thickness of the film 4 in the width direction is almost the same is obtained.

Further, in the present invention, the effective width of the product is generally in the width direction of the resin film 4, and the width of the central portion of both end portions of the resin film 4 is removed. For example, when the full width of the film is 1450 mm, when the film is trimmed 100 mm from both end portions in the width direction of the film toward the center portion side, the effective width of the film product is 1,250 mm.

Next, in the step (b), a "measured thickness profile" is created based on one or more "individual thickness profiles" produced in the above step (a).

In the present invention, the "measuring thickness profile" is for dividing the measurement data relating to the thickness of the film contained in the individual thickness profile into the interval corresponding to the adjustment means 1 at the same interval (that is, for matching The adjustment means 2 is arranged at a specific interval in each section of the width direction of the film (in each section of the lip of the mold 1 in the lip width direction) (hereinafter, abbreviated as "measurement section") Information about the effective width or full width of the film in the width direction of the film.

Further, the "measured thickness profile" is produced based on one or more "individual thickness profiles" as described above, and in the present invention, "measurement thickness profile is made based on one or more individual thickness profiles" In the case where an individual thickness profile is used in the initial setting to produce a measured thickness profile, the individual thickness profile is used as it is, and the measurement of the thickness profile is made. When the measurement thickness profile is initially set, two or more are used. In the case of the individual thickness profile, the profile obtained by adding and averaging the two or more individual thickness profiles to the measurement data relating to the film thickness in each interval is used to produce a measurement thickness profile.

Therefore, in the present invention, the "measured thickness profile formed based on two or more individual thickness profiles" means two or more individual thickness profiles defined above in each interval corresponding to the direction of travel of the film. The measurement data relating to the thickness of the film in the interval, the mean of the profile obtained by adding the average in the direction of migration of the film.

At this time, the measurement data relating to the film thickness in each section is evenly averaged at each measurement point corresponding to the traveling direction of the film and its film thickness measurement value, or in each interval, and has a plurality in the width direction of the film. In the case of measuring points, the average value of the film thickness measurements obtained in each section is taken as the measurement of the film thickness of the interval, and each is moved in the film. It is also possible to create a measured thickness profile by adding the average of the row directions.

Furthermore, in the present invention, two or more individual thickness profiles used in the measurement of the thickness profile may be continuous or discontinuous.

In a preferred embodiment of the present invention, even in the production of the measured thickness profile, the measurement data relating to the thickness of the film is divided into adjustment means for each interval (or per measurement interval). In a single thickness profile, there are a plurality of measurement points in each section of the film width direction, and in the case where a plurality of film thicknesses are obtained in each section, the film thickness measurement values are added and averaged in the interval. The average value is taken as the film thickness measurement value in the interval, and the measured value (average value) of the film thickness is added and averaged in each of the corresponding intervals in the film moving direction, and the measured thickness profile may be produced.

More specifically, in an individual thickness profile, the measurement data relating to the film thickness obtained in the film thickness measurement section corresponding to the section of the adjustment means 1 includes the film thickness measurement measured at 5 points in the width direction of the film. In the case of the value, the average value of the film thickness measurement at 5 o'clock is taken as the film thickness measurement value of the interval, and the values are added and averaged in the moving direction of the film in each corresponding interval to create " Measuring the thickness profile".

Therefore, in the present invention, each measurement of the film in each section (i.e., every adjustment means, or adjustment means per section, or section corresponding to the adjustment means 1 thereof) can be performed in an individual thickness profile. Interval), the average value of the film thickness is calculated, and the measured thickness is prepared as described above. section.

Further, in the present invention, even if the average value of the film thickness measurement values is calculated in each section in an individual thickness profile as described above, the measured thickness profile may be produced. At this time, by using the film thickness measurement values obtained at the respective measurement points as they are, that is, the film thickness measurement values obtained at the respective measurement points are added to the longitudinal direction of the film as they are, and the measurement can be made. Thickness profile.

Further, in the present invention, even when the measurement thickness profile is produced, the profile thickness measurement value at each measurement point may be repeatedly used.

Step (c): Adjusting the lip gap of the mold 1 based on the "measured thickness profile" produced in the above step (b) and the arbitrarily selected "set thickness profile".

Specifically, the "measured thickness profile" produced in the step (b) is compared with the "set thickness profile" described in detail below, and more specifically, in each section of the adjustment means (or the corresponding film thickness) For each measurement interval, the "measured thickness profile" is compared with the "set thickness profile", and the "measured thickness profile" created later is the same as or close to the "set thickness profile", more specifically in each adjustment means 1 In the section (or the corresponding measurement section), the "measurement thickness profile" is equal to or close to the "set thickness profile", and each control means 2 is instructed by the control means 7.

For example, the "predetermined thickness profile" in which the thickness of the film is set to be constant, and the "inverse symbol profile" described in more detail below, etc., can be arbitrarily selected in the present invention. These are used.

First, the "expected thickness profile" may be appropriately adjusted and determined in accordance with the expected thickness of the film product, and may be set to a thickness in the range of, for example, 10 to 300 μm and 30 to 150 μm, and is preferably a constant thickness.

For example, in a certain section, when the thickness of the "measured thickness profile" is larger than the thickness of the "expected thickness profile", the control means 7 gives an instruction to the corresponding adjustment means 2 to narrow the lip gap (ie, close) Further, in the case where the thickness of the "measured thickness profile" is smaller than the thickness of the "expected thickness profile", the control means 7 gives an instruction to the corresponding adjustment means 2 to increase the lip gap (ie, Open the lip).

As a result, in the present invention, steps (a), (b), and (c) are repeated in the migration of the film 4, and the film thickness can be independently adjusted in each section.

Further, in the engineering (B) of the present invention, the thickness of the film 4 is adjusted in such a manner as to satisfy the following conditions.

R ₁ ≦ 2.0 μm, σ ₁ ≦ 0.5 μm, R _AV ≦ 1.0 μm, and σ _AV ≦ 0.2 μm, where R ₁ is the difference between the maximum and minimum thicknesses of the film thickness in the above measured thickness profile, The amplitude of the film thickness in the above-described measured thickness profile (hereinafter, also referred to as "amplitude R ₁ "), and σ ₁ represents the standard deviation of the film thickness in the above-mentioned measured thickness profile (hereinafter, also referred to as abbreviated In the case of "standard deviation σ ₁ ", R _AV is the difference between the maximum value and the minimum value of the film thickness in the cumulative average profile obtained by continuously adding the above-mentioned measured thickness profiles for 100 consecutive times, indicating the cumulative average The amplitude of the film thickness in the cross section (hereinafter, also referred to as "the case of the amplitude R _AV "), and σ _AV indicates the standard deviation of the film thickness in the cumulative average cross section (hereinafter, also referred to as "standard deviation σ _AV "situation").

Further, in the present invention, during the film formation of the film, that is, during the migration of the film, the 100 "measured thickness profiles" continuously produced are added and averaged, that is, in the traveling direction of the film, respectively. In each section of the adjustment means 1, the measurement data relating to the thickness of the film contained in each of the "measurement thickness profiles" which are continuously produced in 100 consecutive times, in detail, in each section, at each measurement point corresponding to the direction of migration of the film The cumulative film thickness measurement value, or the film thickness measurement value in the interval period is taken as the film thickness measurement value of the interval, and the values are accumulated in the moving direction of the film in each corresponding interval, by dividing by the measurement The number of times is 100, and the "cumulative average profile" is created.

Therefore, in the present invention, the "cumulative average cross-section" means that it is included in each of the adjustment means 1 (or the corresponding measurement sections) provided in the width direction of the film, and is arbitrarily moved in the film direction. Information on the average of the film thicknesses in each section of the film transition direction calculated by adding and averaging the measurement data relating to the film thickness contained in 100 consecutive "measured thickness profiles".

Furthermore, the calculation of the "cumulative average profile" is 100 consecutive The measurement data relating to the thickness of the film contained in the "measured thickness profile", even if it is as described above, the average of the film thickness measurements is averaged in each adjustment means 1 interval (or the corresponding measurement interval). The value is also OK.

Further, the "cumulative average profile" is arranged in each section of the adjustment means 1 (or the corresponding measurement section) in the width direction of the film, which means that the full width of the film or the effective width of the product is covered.

Then, in the present invention, the amplitudes R ₁ and R _AV and the standard deviations σ ₁ and σ _AV described in detail below are each calculated by the control means 7.

In the present invention, the control means 7 is not particularly limited, and for example, a control device having an arithmetic processing function is used. Specifically, a PC or the like may be used as appropriate.

In the present invention, in the above-mentioned item (B), the respective adjustment means 2 are instructed by the control means 7, so that the respective amplitudes R ₁ and R _AV and the standard deviations σ ₁ and σ _AV satisfy the above condition: R ₁ ≦ 2.0 (μm), R _AV ≦ 1.0 (μm), σ ₁ ≦ 0.5 (μm), and σ _AV ≦ 0.2 (μm), it is important to adjust the thickness of the film independently in each interval.

Further, in the present invention, for calculating the amplitude (R ₁ ) and the standard deviation (σ ₁ ), one measurement thickness profile is created each time, and the latest measured thickness profile is used to calculate the amplitude (R ₁ ) and the standard deviation. (σ ₁ ) is preferred.

For the calculation of the amplitude (R _AV ) and the standard deviation (σ _AV ), the latest 100 measured thickness profiles are used, and the amplitude (R _AV ) and the standard deviation (σ _AV ) are preferably calculated in order.

For example, in the case where the latest measured thickness profile is created in No. 1200, the amplitude (R ₁ ) and the standard deviation (σ ₁ ) are calculated using the measured thickness profile produced in No. 1200, and before use. The amplitude (R _AV ) and the standard deviation (σ _AV ) of the 100 measured thickness profiles of the created No. 1101 to 1200 were calculated.

The "amplitude (R ₁ )" is calculated from the measured thickness profile of the first time, and is, in detail, the film thickness measurement value of each of the adjustment means 1 intervals (or the corresponding measurement sections) in the thickness measurement section. The difference between the maximum and minimum values.

Further, in the invention, the "measured thickness profile once" means any one of the measured thickness profiles produced by the above operation, and preferably means a newest measured thickness profile.

Further, in the present invention, the amplitude (R ₁ ) represents the accuracy of the film thickness in the measured thickness profile at one time.

In the present invention, the amplitude (R ₁ ) is 2.0 μm or less, preferably 1.5 μm or less, more preferably 1.0 μm or less.

In addition, when the amplitude (R ₁ ) is more than 2.0 μm, the condition of each adjustment of the thickness adjustment means 2 is changed to be large, and it is likely to be affected by hunting or the like, so that the subsequent adjustment of the thickness can be lowered, which is difficult. Achieve high thickness accuracy.

The "standard deviation (σ ₁ )" is calculated from the above-mentioned measured thickness profile, and is specifically the film thickness measurement value of each adjustment means 1 section (or the corresponding measurement section) in the thickness measurement section. The value of the standard deviation.

The standard deviation (σ1) is 0.5 μm or less, preferably 0.4 μm or less, more preferably 0.3 μm or less.

Further, when the standard deviation (σ ₁ ) is larger than 0.5 μm, when the thickness adjustment means 2 provided in each section of the mold 1 adjusts the lip gap, for example, when adjustment is performed in two adjacent sections, The difference in conditional change between the sections becomes large, and since the conditional changes of the approaching adjustment means are mutually affected, the adjustment ability of each section is lowered, the thickness adjustment may take time, and there is a state in which the oscillation cannot be controlled.

The "amplitude (R _AV )" is calculated from the cumulative average cross section, and in detail, the film thickness of each of the adjustment means 1 intervals (or the corresponding measurement sections) in the cumulative average section (that is, 100 consecutive) The difference between the maximum value and the minimum value of the average value of the film thickness measurement values in the traveling direction (or the winding direction) of the film in each section of the thickness profile is measured.

In the present invention, the amplitude (R _AV ) means the deviation width of the film thickness cumulative value in the winding direction when the film is wound into a film web.

Therefore, the larger the value of the amplitude (R _AV ), the greater the possibility of occurrence of a problem in the winding of the ribs or the like, and the smaller the value of the amplitude (R _AV ), resulting in a defect in the winding of the ribs or the like. The possibility of the situation becomes smaller.

Furthermore, the smaller the amplitude (R _AV ), the longer the deviation width of the cumulative value of 100 times in the thickness measurement of the next 100 times, and the time when the thickness is measured once. The deviation width is the same.

The amplitude (R _AV ) is 1.0 μm or less, preferably 0.9 μm or less, more preferably 0.8 μm or less.

Further, when R _{AV is} more than 1.0 μm, there is a high possibility that ribs or the like are generated in the film web.

Further, in the present invention, the film thickness is adjusted in each interval by the adjustment means 2 in the time taken for the measurement of the film thickness by 100 scans, whereby the above condition can be achieved: R _AV ≦ 1.0 μm.

The "standard deviation (σ _AV )" is calculated from the cumulative average cross section, and in detail, the film thickness (i.e., continuous) of each of the adjustment means 1 intervals (or the corresponding measurement sections) in the cumulative average profile The value of the standard deviation calculated from the average of the film thickness measurements in the direction of travel (or the winding direction) of the film in each of the 100 thickness profiles.

In the present invention, the standard deviation (σ _AV ) is 0.2 μm or less.

When the standard deviation (σ _AV ) is larger than 0.2 μm, that is, in the final coiling type, a large deviation occurs in the cumulative value of the film thickness, which means that the ribs have not yet been generated, and the winding is tight. In the tight part, the unevenness of the pyramid or the like is generated, and the loose portion or the like is formed in the loose portion, and the surface quality is likely to be lowered during the processing such as the surface treatment.

Further, in the present invention, the film thickness is adjusted in each interval by the adjustment means 2 during the time taken for the measurement of the film thickness by 100 scans, whereby the above condition can be achieved: σ _AV ≦0.2σm.

And, the film thickness adjustment in the above project (B) In the above, the measured thickness profile is formed according to one or more individual thickness profiles, and the film thickness in the measured thickness profile is determined in a certain interval, and when the film thickness is greater than the expected thickness profile, the mode is adjusted. The lip gap is such that the thickness of the measured thickness profile that is subsequently produced is consistent or close to the expected thickness profile in the interval.

Further, in the present invention, in order to reduce the variation width of the film thickness of the thickness profile, the "reverse symbol profile" is set to the set thickness profile, and the value is within the numerical range of the specific standard deviation described above. It is preferable to give an indication to each of the adjustment means 2 from the control means 7 at any time in such a manner as to produce a thin portion of the thickness.

Here, the "inverse symbol profile" which can be used in the present invention will be described in detail.

In the present invention, the "inverse symbol profile" is the difference between the value of the film thickness of the thickness profile and the film thickness of the desired thickness profile as shown in Fig. 2 (ΔT = "film for measuring the thickness profile" The value of the value of the thickness "-"the value of the film thickness of the thickness profile is expected" is plotted against the opposite.

Therefore, the relationship between the inverse symbol profile and the measured thickness profile is as shown in Fig. 2, and has a symmetrical relationship centering on the expected thickness profile.

For example, when the expected thickness (T _P ) of the film product is set to 100 μm, and the measured value (T _M ) of the film thickness of a certain measurement portion (or measurement point) in the thickness profile is 101 μm, the measured value (T) is measured. The difference between the value of _M ) and the expected thickness (T _P ) (ΔT = T _{M -} T _P ) becomes "+1 μm". At this time, the symbol "+ (positive)" has an inverse sign of "-(negative)", and the value of the thickness of the inverse symbol cross section at this time is "-1 μm".

Here, in the film thickness adjustment (initial adjustment) at the start of film formation, the film thickness measurement is performed at least in the film measurement section corresponding to each section of each thickness adjustment means, and the adjustment target is obtained. The initial set value of the film formation is the expected thickness (or the expected thickness profile).

However, for example, the set thickness profile is set to the desired thickness profile, and as shown in FIG. 3, the average thickness profile is added for a certain period of time (for example, after the initial adjustment of the film thickness precision is performed, the thickness profile is measured at a certain point in time). The cross section calculated by adding and averaging is the cross section (i), and the measured thickness profile produced after that is the cross section (ii), and then the summed average thickness profile (that is, the film thickness precision will be obtained from the film thickness) After the initial adjustment, the profile obtained by adding and averaging the measured thickness profiles at the time of the production of the section (ii) is the same as the section (iii) of FIG.

Therefore, the sum of the average thickness profiles thus indicates a behavior close to the measured thickness profile that is newly added for each calculation at the time of production. In general, there is almost no thickness of all measurement sites (or measurement points) on the film. It is expected that the thicknesses are completely the same, and therefore, the final addition average thickness profile (that is, the profile obtained by adding and averaging the measured thickness profiles at the time of the initial adjustment of the film thickness precision to the end of the winding of the film) It is hardly consistent with the expected thickness profile.

Here, in the present invention, as in the above, in the adjustment of the film thickness, in the measured thickness profile formed according to one or more individual thickness profiles, it is judged that the thickness of the film is larger than the expected thickness. In this case, it is not only used to adjust the thickness of the film thickness close to the expected thickness, but also to reduce the amplitude of the film thickness of the average thickness, and to set the inverse symbol profile as the setting. In the thickness profile, it is preferable to give an instruction from the control means 7 to the adjustment means 2 in such a manner that the thin portion is deliberately generated within the numerical range of the above-mentioned specific standard deviation. In this way, by adjusting the thickness, the cumulative average cross-section is extremely close to the expected thickness profile, or uniform, and the uniformity of the film thickness can be obtained, and the appearance quality of the film roll can be improved.

Furthermore, such an inverted symbol profile can be made from the above-described measured thickness profile made from one or more individual thickness profiles. Furthermore, the setting can be automatically performed in the control means 7.

However, each time a thickness profile is made from a thickness profile, and the inverse symbol profile is created based on the measured thickness profile, the complexity of the control device included in the control means 7 is increased, resulting in a functional burden and a reflection. Problems such as measurement errors. Therefore, at least two or more, preferably 10 or more, more preferably 20 or more, and preferably 30 or more individual thickness profiles are prepared for each thickness profile, and the thickness profile is measured according to the measured thickness profile. The inverse sign surface is preferred.

Furthermore, in contrast, each time a measured thickness profile is made from too many individual thickness profiles, for example 1000 individual thickness profiles, and is set to produce an inverse symbol profile corresponding to the measured thickness profile, a desired number of individual thicknesses are made. The time taken for the profile and the thickness profile to be measured according to this becomes longer, which is the reason why during this period there is a storm caused by the cumulative thickness. The ills of the ribs and the like.

Therefore, the number of individual thickness profiles used in the measurement of the thickness profile can be determined by the time required to produce a single thickness profile, the time required to produce a thickness profile, and the take-up time of the film product (making a The time of the film web) is appropriately set.

Further, in the film thickness adjusting means, for example, the above-described heat bolt type actuator can be used. In this case, the thickness of the film is adjusted by adjusting the lip gap in each section by expanding and contracting the bolt in response to electric heat. Therefore, since the time (reaction time) from the setting of the inverse symbol cross section to the start of the adjustment of the film thickness becomes long, there is a case where a control delay called oscillation is generated.

Therefore, in view of such time, it is preferable to determine in advance the number of individual thickness profiles used for making the inverse symbol profile.

Further, for the same reason, as the set value of the inverse symbol cross section, it is effective to add or subtract the amplitude of the thickness of the control delay portion caused by the oscillation in advance to the thickness difference (ΔT).

The film roll thus obtained is suitably used as a light diffusing film, a protective film for protecting the surface of a constituent member of a flat display, or a polarizing plate, in a flat display such as a liquid crystal display device or a plasma display. It is used as a material such as a protective film of a polarizer.

[Examples]

Hereinafter, the embodiments of the present invention will be described, but the present invention is not limited to the embodiments.

(Example 1)

For the thermoplastic resin, 30 parts by weight of "SUMIPEX HT01X" manufactured by Sumitomo Chemical Co., Ltd. and polymethyl methacrylate (PMMA) were mixed with a polymethyl methacrylate (PMMA) resin containing acrylic acid. Acrylic resin obtained by using 70 parts by weight of "SUMIPEX EX" manufactured by Sumitomo Chemical Co., Ltd.

As shown in Fig. 1, the mold 1, the adjustment means 2, the rolls 3, 3' and 3", the thickness of the film, the measuring device 5, the film web 6 and the control means 7, and the measuring device 5 and the film roll are arranged. A slitter (not shown) is disposed between the materials 6.

As the mold 1, a mold having a mold width of 1,650 mm, along the die lip width of the mold 1, is provided with a heat bolt type actuator having 65 bolts at intervals of 25 mm along its lip width (1650 mm). Thickness adjustment means. As the measuring device 5, a radiation transmission type thickness measuring device was used, and the measurement interval was set to 5 mm intervals in the film width direction orthogonal to the film moving direction. Further, the effective width of the product of the film was set to 1250 mm.

In the control means 7, based on the measurement data transmitted from the measuring device 5, the measurement data obtained by performing the measurement from the end portion to the end portion of the film in the width direction is performed based on the measurement data once divided. , making an individual thickness profile and making a measured thickness profile based on the one individual thickness profile. Next, the measured thickness profile is prepared in such a manner that the latest measured thickness profile produced in each section is compared with the expected thickness profile (thickness of 80 μm and a constant profile) selected as the set thickness profile. The measured thickness profile produced thereafter is set so that each of the adjustment means 2 is instructed from the control means 7 so that each section coincides with the expected thickness profile. Further, in parallel with this, the following conditions are satisfied: R ₁ ≦ 2.0 μm, R _AV ≦ 1.0 μm, σ ₁ ≦ 0.5 μm, and σ _AV ≦ 0.2 μm, and each of the adjustment means is set from the control means 7 Give instructions.

Further, in the control means 7, when the thickness profile is measured from the individual thickness profile, the measurement data transmitted from the measuring device 5 to the control means 7 corresponds to the 5-point film of the adjustment means (i.e., the bolt) 1 section. The average value of the thickness measurement values is taken as the measurement value of such a section, and is set to produce a measurement thickness profile.

Here, a thermoplastic resin film is produced, specifically, the following.

First, a one-axis extrusion (manufactured by Hitachi Shipbuilding Co., Ltd., screw diameter: 130 mm φ) was used to melt-extrude the above-mentioned acrylic resin into a film shape from a mold having a mold width of 1,650 mm (die width: 1650 mm). The resin was sandwiched between 3 and 3', and the resin was molded and solidified in contact with the other cooling roll 3" to obtain a thermoplastic resin film having a desired product thickness (reference thickness) of 80 μm.

Further, the thickness of the thermoplastic resin film here is a thermoplastic resin film which is formed by cutting in a wide direction, and the thickness of the effective width of the 20-point product is measured at equal intervals in the width direction by a micrometer, and the thickness is measured. The average thickness of 20 points.

Further, the film thickness accuracy was initially adjusted to about ±2 μm by manual adjustment.

Further, the thermoplastic resin film obtained from a mold of 1650 mm (mold lip width: 1650 mm) has a full width of about 1450 mm.

After the thermoplastic resin film was passed through the cooling roll 3", the radiation-transmissive thickness measuring device 5 was used to transfer the film from one end of the film to the other at each measuring point (interval: 5 mm). The end portion scans the thickness of the film to measure the film thickness, and then continuously scans from the other end portion to the film thickness measurement at one end portion. The measurement data is all sent to the control means 7, With the above setting, the scanning measurement of the thickness in the width direction of the film is performed once (that is, each end scanning from one end of the film width to the other end, or scanning from the other end to one side) The end portion is measured. Each of the individual thickness profiles and the measured thickness profile are separately produced, and the adjustment means 2) provided in the mold 1 is controlled in each section.

The film is passed through the film 4 of the thickness measuring device 5, and then the width of the film is made into a width (1250 mm) by the slitter, and the both ends of the film are slit (cut) using a coiler. The film was taken up, and finally a film of a total length of 2000 m was taken up in a roll core (diameter: 152.4 mm) to prepare a film roll 6.

The amplitude (R ₁ ) and the standard deviation (σ ₁ ) calculated by measuring the thickness profile obtained during the initial adjustment of the thickness of the film after the initial adjustment of the thickness of the film as described above, and The amplitude (R _AV ) and the standard deviation (σ _AV ) are shown in Table 1 below for the average of all the calculated values.

Further, in the first embodiment, the number of measured thickness profiles produced from the initial adjustment of the film thickness precision to the time of obtaining the final film web was 200.

(Example 2)

In the above-described first embodiment, in addition to the desired thickness profile selected as the set thickness profile (that is, the thickness is 80 μm and a certain profile), instead of the inverse symbol profile, a measurement is made based on the 20 individual thickness profiles. A film web was produced in the same manner as in the above-described first embodiment except for the thickness profile.

The amplitude (R ₁ ) and the standard deviation (σ ₁ ) and the amplitude (R) calculated from the measured thickness profile prepared after the initial adjustment of the thickness accuracy of the film to the final film roll. _AV ) and standard deviation (σ _AV ) are shown in Table 1 below for the average of all the calculated values.

Further, in the second embodiment, the number of measured thickness profiles produced from the initial adjustment of the film thickness precision to the time of obtaining the final film web was 200.

(Comparative Example 1)

Unless otherwise changed, in the first embodiment, the initial thickness adjustment by manual is not performed, and each of R ₁ , R _AV , σ _{1 ,} and σ _AV satisfies the following conditions: R ₁ ≦ 4.0 μm, R _AV ≦ 2.0 μm. In the same manner as in the above-described first embodiment, a film web was produced by changing the setting from the control means 7 to the adjustment means 2 in a manner of σ ₁ ≦ 1.0 μm and σ _AV ≦ 0.5 μm.

The amplitude (R ₁ ) and the standard deviation (σ ₁ ), and the amplitude (R _AV ) and the standard deviation (σ _AV ) calculated from the measured thickness profile prepared until the final production of the film web are shown in Table 1 below. Each represents the sum of all the calculated values.

Further, in Comparative Example 1, the number of measured thickness profiles prepared up to the final production of the film web was 200.

(assessment means)

Appearance: For the film webs produced in the above Examples and Comparative Examples, the appearance of the film was visually inspected, and the problem of no gluten or pyramid on the surface of the film web was evaluated as "◎". In addition, although there are some irregularities of the pyramid shape, the degree of influence on the subsequent post-processing is evaluated as "○". Then, the person who apparently produces the pyramid and the ribs is evaluated as "X".

As described above, in the present invention, the thickness of the film in the transition is measured in the wide direction to produce individual thickness profiles, according to one or more individual thickness profiles (one in the embodiment 1, in the second embodiment) A measured thickness profile is produced for each of 20 individual thickness profiles, and the measured thickness profile and the set thickness profile (the expected thickness profile in Example 1 and the inverse symbol profile in Example 2) are based on the results. The thickness of the film is independently adjusted for each interval. Then, in parallel with this, according to the 100 measured thickness profiles continuously produced, each of the intervals is adjusted under the conditions of satisfying R ₁ ≦ 2.0 μm, R _AV ≦ 1.0 μm, σ ₁ ≦ 0.5 μm, and σ _AV ≦ 0.2 μm. As a result of the thickness of the film, in the present invention, as shown in Table 1, a film roll excellent in appearance can be produced without using vibration.

In particular, in Embodiment 2, it is possible to manufacture a thin-moulded web which is completely free from the appearance problems of ribs or pyramids and the like.

Furthermore, in the second embodiment, the number of individual thickness profiles used for the measurement of the thickness profile is set to 20 (and, in the embodiment 1, the number of individual thickness profiles used for the measurement of the thickness profile is one) And, in terms of setting the thickness profile, the appearance of the film web is remarkably improved by using the inverse symbol profile.

On the other hand, in Comparative Example 1, although the film thickness was adjusted in accordance with the measurement of the thickness profile in the same manner as in Examples 1 and 2, the film roll produced had a rib and a pyramid, and a good film web could not be obtained. The appearance.

As a result, by using the production method of the present invention, a film web having an excellent appearance can be produced.

The present invention claims priority based on Japanese Patent Application No. 2012-114439, the entire disclosure of which is incorporated herein by reference.

1‧‧‧Mold

2‧‧‧Adjustment means

3‧‧‧ casting rolls

3'‧‧‧ casting rolls (or counter rolls)

3"‧‧‧ casting rolls (or cooling rolls)

4‧‧‧ thermoplastic resin film

5‧‧‧ thickness gauge

6‧‧‧ film coil

7‧‧‧Control means

Claims (6)

A method for producing a film web comprising the following steps (A) to (C): (A) pressing from a mold having an adjustment means of a lip gap a thermoplastic resin, which is formed by filming while moving, and forming a film; (B) in the process of moving the film, the process of adjusting the thickness of the film, that is, repeating the following steps (a) to (c), The process of adjusting the thickness of the film, (a) measuring the thickness of the film in the transition at a specific interval in the width direction of the film orthogonal to the direction of travel of the film, and forming a step of individual thickness, (b) Or the individual thickness profile of the above, the step of measuring the thickness profile, (c) the step of adjusting the lip gap of the mold according to the measured thickness profile, and the set thickness profile; (C) rolling the film into a roll In the project (B), the thickness of the film is adjusted to satisfy the following conditions, R ₁ ≦ 2.0 μm, σ ₁ ≦ 0.5 μm, R _AV ≦ 1.0 μm, and σ _AV ≦ 0.2 μm. [wherein, R ₁ is of the time-based measurement of the maximum cross-sectional thickness of the film thickness The difference between the minimum value, which represents the amplitude of the measured thickness profile of the film thickness, σ ₁ represents the standard time-based measurement of the thickness profile of film thickness variations, R _AV system 100 represents a consecutive fabrication of the cross-sectional thickness measurement and are added The difference between the maximum value and the minimum value of the film thickness in the cumulative average profile obtained is the amplitude of the film thickness in the cumulative average profile, and σ _AV is the standard deviation of the film thickness in the cumulative average profile]. The method for producing a film web according to claim 1, wherein in the step (a), the end portion from one end of the width direction of the film to the other end is measured at a specific interval, or One measurement of the individual thickness is made from the measurement data relating to the film thickness obtained from the other end to the end of one of the ends. The method for producing a film web according to claim 1, wherein in the step (b), the measured thickness profile is produced based on two or more individual thickness profiles. The method for producing a film web according to any one of claims 1 to 3, wherein the set thickness profile is selected from the group consisting of a desired thickness profile and a reverse sign profile. The method for producing a film web according to the fourth aspect of the invention, wherein the set thickness profile is an inverse symbol cross section. The method for producing a film web according to claim 5, wherein the inverse sign profile is produced based on the measured thickness profile for each of the measured thickness profiles.