TW201540633A - Film roll and production method thereof, and film sheet production method - Google Patents

Abstract

There are provided a film roll in which overlapped films hardly stick to each other at the time of winding the film into a roll and a production method thereof, and a film sheet which is cut from the film roll and a production method thereof. A film roll consists of a winding core for winding a long object around a circumferential surface thereof, and a long film which is wound around the circumferential surface of the winding core into a roll. Upon being wound into a roll, a surface of the film is applied with contact pressure. At the portion of the surface of the film, to which the contact pressure in the range of 0.05 MPa to 0.10 MPa is applied, a coefficient of static friction is at most 1.2. Protrusions including fine particles, each of which has a height of at least 30 nm, are formed on the surface of the film, and thereby the coefficient of static friction is held as low as at most 1.2 even under the contact pressure described above.

Description

Film roll, method of manufacturing the same, and method of manufacturing film sheet

The present invention relates to a film roll obtained by winding a long polymer film in a roll form, a method for producing the same, and a method for producing a film sheet.

A polymer film (hereinafter referred to as a film) is widely used as a protective film of a polarizing plate, an optical film such as a retardation film, an antireflection film, and a transparent conductive film.

The film is generally produced in an elongated shape, and as a manufacturing method, there is a solution film forming method. The solution film forming method is, for example, a method in which a solution in which a polymer is dissolved in a solvent (hereinafter referred to as a dope) is continuously cast on a surface of a support by a casting die to form a strip-shaped cast film, and The support is peeled off and dried. The elongated film is wound up in a roll shape on the circumferential surface of the core and stored as a film roll.

The elongated film needs to have a function of slidability between the films and a function of not causing a winding deviation between the films in order to take up the roll. In order to impart the former function to the film, a matting agent is added to the film. In order to impart the latter function to the film, embossing (knurling) processing is performed on both end portions in the width direction of the film. In addition, the method of winding up the elongated film is: winding the film in a manner of aligning the side edges of the film (linear winding); and winding the side edge of the film in a certain range in the width direction Method (swing (oscillation) winding). Further, Japanese Laid-Open Patent Publication No. 2010-150041 discloses a method of combining linear winding and oscillating winding to wind up a film so as not to cause edge stretching and winding deviation on the film roll after winding. Here, the edge stretching means a phenomenon in which both end portions (edge portions) of the film are stretched in the width direction. Further, the winding deviation means a phenomenon in which the positions of the both side edges in the film roll are deviated from the desired position.

However, even if the edge stretching and the winding deviation are prevented by the winding method using the film of Japanese Patent Laid-Open Publication No. 2010-150041, the contact surface pressure is generated in the portion where the film overlaps in the film roll. The longer the length of the film, the higher the contact surface pressure, especially near the core. Thus, by controlling the winding method, it is impossible to avoid an increase in the contact surface pressure.

When the contact surface pressure increases in the film roll, depending on the type of the film, the overlapping portions of the film are attached to each other with a certain probability, and it is difficult to slide. Thus, the overlapping films are attached to each other due to excessive pressure applied to the surface of the film, etc. This phenomenon is also referred to as adhesion. Since the films are attached to each other and are difficult to slide, it is impossible to reduce the deformation at the time of winding up the film by sliding. Therefore, a failure of the film to be deformed toward the core side due to depressions and wrinkles in the circumferential direction, irregularities of the core, and film end faces (notches) at the time of winding is generated in the conventional film roll (hereinafter referred to as Core side transfer failure). The thinner the film, and the lower the elastic modulus of the film, the more easily the concave portion, the wrinkles, and the core side transfer failure occur, and thus it is a problem particularly in a thin film and a film having a low elastic modulus.

Accordingly, it is an object of the present invention to provide a film roll, a method for producing the same, and a method for producing a film sheet, in which the adhesion of a film which is superposed when being wound into a roll is reduced.

The film roll of the present invention is provided with a core and an elongated polymer film. Polymer film It is wound in a roll in a winding core. The portion of the film surface to be applied to the polymer film having a contact surface pressure of 0.05 MPa or more and 0.10 MPa or less has a static friction coefficient of 1.2 or less.

It is preferable to form protrusions having a height of the particles of 30 nm or more in a range of 10 ⁴ or more and 10 ⁶ or less per 1 mm ^{2 of the} film surface.

The polymer film is preferably a cellulose halide film.

It is preferable to form the protrusion after the saponification of the film surface in the range of 10 ⁴ or more and 10 ⁶ or less per 1 mm ² of the film surface.

The polymer film is used by adhering a polarizing film to the above-mentioned film surface after the saponification treatment.

The particles are preferably cerium oxide.

The method for producing a film roll of the present invention includes a dope production step (A step), a cast film forming step (B step), a stripping and drying step (C step), and a winding step (D step). In the step A, a dope composition containing a polymer, a solvent for dissolving the polymer, and fine particles dispersed in the state of secondary particles is produced. In the dope composition, the content ratio of the fine particles having a secondary particle diameter of 0.7 μm or more to the total number of fine particles is at least 30%. In the step B, a cast film is formed on the support by continuously discharging the dope composition from the casting die to the continuously running support. In the step C, the cast film was peeled off from the support and dried to obtain a polymer film. In step D, the polymer film is taken up on the core.

The above step A is preferably carried out by a raw material dope preparation step (E step), a mixture preparation step (F step), a fine particle dispersion step (G step), and a mixing step (H step). In the step E, the polymer and the solvent are mixed, and the polymer is dissolved in a solvent by at least any one of heating and stirring to prepare a raw material dope. In the F step, the above polymerization will The polymer and the solvent of the same composition as the above solvent and the above-mentioned fine particles are mixed and stirred to obtain a liquid mixture. In the G step, fine particles are dispersed as secondary particles in the mixture to obtain a fine particle dispersion. In the fine particle dispersion, the content ratio of the fine particles of the secondary particle diameter of 0.7 μm or more to the total number of the fine particles is at least 30%. In the H step, the raw material dope and the fine particle dispersion are mixed to obtain a dope composition.

The method for producing a film sheet of the present invention comprises the above-described A step, the above B step, the above C step, the above D step, and the cutting step (I step). In step I, the polymer film is pulled from the film roll and the film piece is cut from the drawn polymer film.

According to the film roll of the present invention and the method for producing the same, the adhesion of the film which is superimposed on the film roll is reduced even if it is affected by the contact surface pressure when wound into a roll. Further, according to the method for producing a film sheet of the present invention, the influence of the adhesion of the film which is superposed on the film roll is reduced.

10‧‧‧film

10a‧‧‧film surface

12‧‧‧ Film body

13‧‧‧Face

14‧‧‧Particles

15‧‧‧ Protrusion

20‧‧‧Polar plate

22‧‧‧ Film roll

30‧‧‧solution film making equipment

31‧‧‧ Concentrate preparation device

37‧‧‧Winding device

41‧‧‧1st concentrate

42‧‧‧2nd concentrate

Fig. 1 is a cross-sectional view showing an outline of a film.

Fig. 2 is an enlarged cross-sectional view showing the vicinity of the film surface of the film of Fig. 1.

Fig. 3 is a cross-sectional view showing an outline of a polarizing plate produced by using the film of Fig. 1.

Fig. 4 is an enlarged schematic cross-sectional view showing a portion in which the films of Fig. 1 overlap each other and a portion in which the polarizing plates of Fig. 3 overlap each other.

Fig. 5 is an explanatory view showing an outline of a film roll according to an embodiment of the present invention.

Fig. 6 is an explanatory view showing the correlation between the winding length of the film and the contact surface pressure.

Fig. 7 is an explanatory view showing an outline of a solution film forming apparatus.

Fig. 8 is an explanatory view showing an outline of a winding device.

Fig. 9 is an explanatory view showing the correlation between the content ratio of the fine particles having a secondary particle diameter of 0.7 μm or more to the total number of fine particles and the density of the protrusions having a height of 30 nm or more.

Figure 10 is an AFM image relating to the film produced in Experiment 1-D.

11 is an example of an image obtained by performing binarization processing on the AFM image of FIG. 10 by using a luminance corresponding to a projection height of 10 nm as a threshold value.

Fig. 12 is an example of an image obtained by performing binarization processing on the AFM image of Fig. 10 with the luminance corresponding to the projection height of 30 nm as a threshold value.

Fig. 13 is an explanatory view showing a method of measuring the static friction coefficient with respect to the contact surface pressure.

Fig. 14 is an explanatory view showing changes in the frictional force between the fixed side test piece and the sliding side test piece with respect to the respective displacement amounts of the slide piece.

Fig. 15 is an explanatory view showing changes in the static friction coefficient with respect to the contact surface pressure for each experiment.

Fig. 16 is an explanatory view showing the correlation between the density of the protrusions having a height of 10 nm or more and the ratio of the adhesion area of the film.

Fig. 17 is an explanatory view showing the correlation between the density of the protrusions having a height of 30 nm or more and the ratio of the adhesion area of the film.

Fig. 18 is an explanatory view showing the correlation between the density of the protrusions having a height of 40 nm or more and the ratio of the adhesion area of the film.

Fig. 19 is an explanatory view showing the correlation between the density of the protrusions having a height of 50 nm or more and the ratio of the adhesion area of the film.

Fig. 20 is an explanatory view showing the correlation between the height of the protrusion and the contribution rate of the protrusion to the reduction of the attachment.

Fig. 21 is an explanatory view showing the correlation between the ratio of the content of the fine particles having a secondary particle diameter of 0.7 μm or more to the total number of particles and the ratio of the attached area.

The film 10 shown in FIG. 1 includes a film main body 12 and a surface layer 13 disposed on both surfaces of the film main body 12. Although the boundary between the film main body 12 and the surface layer 13 is not observed, in Fig. 1, the boundaries thereof are illustrated for convenience of explanation.

The film body 12 is composed of a cellulose halide and an additive. The pair of skin layers 13 are composed of the same components. Specifically, any of the surface layers 13 is composed of cellulose halides, fine particles 14, and additives, and the ratio is also the same. The additives are plasticizers, ultraviolet absorbers, delayed retardation inhibitors for controlling the film 10, and the like. The film body 12 and the pair of skin layers 13 may not contain an additive. The surface of the microparticles 14 is covered with a hydrophobic group and exhibits a secondary particle state of silicon dioxide (SiO ₂ ). In addition, the fine particles 14 may be used together with or instead of cerium oxide, using titanium dioxide, aluminum oxide, zirconium oxide, calcium carbonate, talc, clay, calcined kaolin, calcined calcium citrate, calcium citrate hydrate, Microparticles such as aluminum citrate, magnesium citrate, and calcium phosphate. The details of the fine particles 14 will be described later.

The cellulose halide of the film main body 12 is Triacetyl Cellulose (TAC), and the cellulose halide of the surface layer 13 is TAC. However, the respective cellulose halides of the film main body 12 and the surface layer 13 are not limited thereto. For example, the cellulose halide of the film main body 12 may be made of Diacetyl Cellulose (DAC), and the cellulose halide of the surface layer 13 may be TAC. Further, in the present embodiment, each of the polymer components of the film main body 12 and the surface layer 13 is made of a cellulose halide, but it may be a polymer which can be formed into a film by a solution film forming method. As other polymers, for example, cyclic polyolefin, C Oleic acid, polyethylene terephthalate (PET), and the like.

When the two skin layers 13 are composed of the same components, the ratios thereof may be different from each other. Also, it may be that only one of the two skin layers 13 contains the aspect of the particles. Further, a single-layer structure composed of the film main body 12 may be used instead of the two surface layers 13, and the film main body 12 may be formed of a cellulose halide, an additive, and fine particles 14.

The thickness T10 of the film 10 was set to 60 μm , the thickness T12 of the film main body 12 was set to 54 μm , and the thickness T13 of the surface layer 13 was set to 3 μm . However, the thickness is not limited to this, as long as the thickness T10 is in the range of 10 μm or more and 80 μm or less, the thickness T12 is in the range of 8 μm or more and 75 μm or less, and the thickness T13 is in the range of 1 μm or more and 10 μm. The following range is sufficient. When the thickness T10 is in the range of 15 μm or more and 60 μm or less, the effect of reducing the adhesion of the overlapping portions of the present invention when winding the film 10 is particularly large. The thicknesses T10, T12, and T13 can be calculated by the concentration and flow direction of the respective solids according to the first dope 41 (see FIG. 7) and the second dope 42 (see FIG. 7) which will be described later (see Figure 7) The amount is obtained.

Further, when the film 10 is a low elastic modulus film having an elastic modulus of 3.0 GPa or less, the effect of reducing the adhesion of the films 10 to each other is also large. Here, a sample piece of 2 cm × 15 cm was prepared from the film 10, and the sample piece was subjected to a tensile test, whereby the elastic modulus of the film 10 was measured. The tensile test was carried out, for example, using a Strograph manufactured by Toyo Seiki Seisaku-sho Ltd. The tensile test conditions were such that the distance between the two chucks holding the sample sections was 10 cm and the speed of the crosshead was 200 mm/min.

A part of the fine particles 14 in the film 10 is set to protrude from a film surface 10a formed of TAC as a polymer component by a certain height or more, each of which functions as the protrusion 15. For example, as shown in Fig. 2, the particles 14a constitute a height H15a protruding from the film surface 10a. The protrusions 15a and the particles 14b constitute the protrusions 15b having the height H15b. Here, the height H [unit: nm] protruding from the film surface 10a is defined as the distance between the film surface 10a and the apex of the portion exposed from the film surface 10a. In addition, in the first drawing, the second drawing, and the fourth drawing, for the sake of convenience of explanation, the protrusion 15 is formed only by the particles 14 formed, but the aspect of the protrusion 15 is not limited thereto. The protrusions 15 may also be formed in any manner based on the particles 14, and may be formed, for example, by a composite additive and a cellulose halide in the particles 14. When the protrusion 15 is formed only by the particles 14, the apex of the height H is determined to be the apex of the particles 14. When the protrusions 15 are formed by the composite additive and the cellulose halide in the particles 14, the apex of the height H is determined to be the apex of the particles, the apex of the additive, and the apex of the cellulose sulphate which is the farthest from the film surface 10a. .

By providing a plurality of protrusions 15 on the film surface 10a by the fine particles 14, minute irregularities are formed on the film surface 10a, and the film surface 10a is given a certain roughness. By the unevenness, even if the films 10 overlap each other, they do not adhere to each other, and it is possible to ensure the sliding of the films 10 with each other, thereby exhibiting a certain scratch resistance. Thus, the microparticles 14 function as a so-called matting agent.

When the height H of the protrusions 15 is 30 nm or more, the effect of reducing the adhesion of the films 10 or improving the slidability is large as compared with the case where the height H of the protrusions 15 is less than 30 nm. As the protrusions 15 become higher, the effect of reducing sticking or improving slidability is increased, and when the height H of the protrusions 15 is 40 nm or more, the effect of reducing the adhesion of the films 10 or improving the slidability is further increased. Further, when the height H of the protrusions 15 is 100 nm or less, the haze of the film 10 is lower than that in the case where the height H is higher than 100 nm, which is preferable.

The number of protrusions 15 having a height H or more per 1 mm ^{2 of the} film surface 10a is defined as a protrusion density D (H) [unit: unit/mm ² ]. When the protrusion density D (30) having a height of 30 nm or more is 10 ⁴ /mm ² or more, the effect of attaching and imparting slidability are reduced as compared with the case where the protrusion density D (30) is less than 10 ⁴ /mm ² . The effect is greater. As the protrusion density D (30) increases, the effect of reducing the adhesion and the effect of imparting slidability is increased, and when the protrusion density D (30) is 2 × 10 ⁴ /mm ² or more, the effect of sticking is reduced and The effect of imparting slidability is further increased. Further, when the projection density D (30) is 10 ⁶ /mm ² or less, the haze of the film 10 is suppressed to be lower than the case where the projection density D (30) is more than 10 ⁶ /mm ² . When the protrusion density D (30) is 5 × 10 ⁵ /mm ² or less, the haze of the film 10 is suppressed to be lower. Further, regarding the protrusion density D (40), the range in which the effect of reducing the adhesion and the effect of imparting slidability is large and the range in which the haze is suppressed to be low are also the same as the protrusion density D (30).

When the film 10 is used as a protective film of a polarizing plate, the film 10 is subjected to saponification treatment. As shown in FIG. 3, the polarizing plate 20 includes a polarizing film 17 and a pair of films 10, and the film 10 is disposed on each surface of the polarizing film 17. The saponification treatment is carried out in order to increase the adhesion to the polarizing film 17. The film surface 10a of the film 10 opposite to the film surface 10a to which the polarizing film 17 is bonded is the surface 20a of the polarizing plate 20.

The saponification treatment of the film 10 is carried out, for example, as follows. The film 10 was immersed in a 2.0 mol/L potassium hydroxide (KOH) aqueous solution for 2 minutes, and then washed with pure water, and subjected to sulfuric acid (H ₂ SO ₄ aq) as a neutralizing solution at 0.05 mol/L for 20 seconds. Neutralization, washing again with pure water, and drying at 100 °C. Not limited to this, any method generally known can be used. Further, the saponification treatment is usually carried out on the two film faces 10a of the film 10, and in the present embodiment, the two film faces 10a are also carried out.

The polarizing film 17 is produced by adsorbing a molecule containing iodine molecules to a film made of polyvinyl alcohol (PVA) and orienting the PVA and the compound containing iodine. A PVA-based adhesive is used for bonding the film 10 and the polarizing film 17. In addition, partial The light film 17 is not limited thereto, and may be any one as long as it is generally used as a polarizing film. Further, in the present embodiment, the film 10 is bonded to both surfaces of the polarizing film 17 to form the polarizing plate 20, but the configuration is not limited thereto. For example, the film 10 may be adhered to only one side of the polarizing film 17, and a protective film layer such as PET may be provided on the outermost surface of the film 10 to which the polarizing film 17 is bonded.

The film 10 is swollen by saponification treatment, and further absorbs moisture to be easily swollen. Therefore, the height Hk [unit: nm] of the fine particles 14 after the saponification treatment (after the saponification treatment) protrudes from the film surface 10a is lower than the height H before the saponification treatment (before the saponification treatment). The film 10 after the saponification treatment is also the same as the film 10 before the saponification treatment, and when the height Hk of the protrusions 15 is 30 nm or more, the portions of the film 10 which are overlapped are reduced from each other as compared with the case where the height Hk of the protrusions 15 is less than 30 nm. The effect of attaching or improving the slidability is large. As the protrusions 15 become higher, the effect of reducing the adhesion or improving the slidability is increased, and when the height Hk of the protrusions 15 is 40 nm or more, the effect of reducing the adhesion of the portions of the overlapping films 10 or the improvement of the slidability is further increased. . Further, in the same manner as before the saponification treatment, even when the height Hk of the protrusions 15 is 100 nm or less after the saponification treatment, the haze of the film 10 is lower than that in the case where the height Hk is higher than 100 nm, which is preferable.

Further, in the film 10 after the saponification treatment, the number of protrusions having a height Hk of 30 nm or more is smaller than that of the film 10 before the saponification treatment, but has an effect of reducing the adhesion. Here, the number of the protrusions 15 having a height Hk or more per 1 mm ² of the film surface 10a after the saponification treatment is referred to as a protrusion density Dk (Hk) [unit: unit/mm ² ]. The film 10 after the saponification treatment is also the same as the film 10 before the saponification treatment, and when the protrusion density Dk (30) having a height of 30 nm or more is 10 ⁴ /mm ² or more, the protrusion density Dk (30) is less than 10 ^{4 .} Compared with the case of mm/mm ² , the effect of reducing the adhesion and the effect of imparting slidability are large. As the protrusion density Dk (30) increases, the effect of reducing the adhesion and the effect of imparting slidability is increased, and when the protrusion density Dk (30) is 2 × 10 ⁴ /mm ² or more, the effect of sticking is reduced and The effect of imparting slidability is further increased. Further, when the protrusion density Dk (30) is 10 ⁶ /mm ² or less, the haze of the film 10 is suppressed to be lower than the case where the protrusion density Dk (30) is more than 10 ⁶ /mm ² . When the protrusion density Dk (30) is 5 × 10 ⁵ /mm ² or less, the haze of the film 10 is suppressed to be lower. Further, regarding the protrusion density Dk (40), the range in which the effect of reducing the adhesion and the effect of imparting the slidability is large and the range in which the haze is suppressed to be low are also the same as the protrusion density Dk (30).

Further, since the surface 20a of the polarizing plate 20 has the same configuration as that of the film surface 10a after the saponification treatment, the polarizing plate 20 has the same conditions as those of the film 10 after the saponification treatment, and also has the reduction of the polarizing plates 20. Attach and impart slidability.

Hereinafter, the film 10 before the saponification treatment, the film 10 after the saponification treatment, or the polarizing plate 20 (collectively referred to as a film or the like 10, 20) will be overlapped by the fourth, fifth, and sixth figures. The case where the film is wound into a roll and becomes a film roll will be described.

As shown in Fig. 4, when two films 10 and 20 are superposed on each other, the film faces 10a and 20a of any of the films 10 and 20 are in contact with each other. Protrusions 15 based on the particles 14 are formed on the opposing film faces 10a, 20a. By the projections 15, the direct contact of the opposing film faces 10a, 20a is partially blocked. Therefore, the two films 10 and 20 are not partially attached to each other.

As shown in Fig. 5, the film roll 22 is composed of a winding core 23 and a film or the like 10 and 20 wound around the winding core 23. The core 23 has a substantially cylindrical shape, and a film or the like 10 and 20 are wound around the outer peripheral surface. The core inner peripheral surface of the winding core 23 is provided with a core grip portion 23a for fixing the unwinding when the winding core 23 is attached to the winding device 37 (see Fig. 8). Films, etc. 10, 20 are long The shape is taken up in a roll shape on the circumferential surface of the winding core 23.

In the film roll 22, the contact surface pressure is applied to the film faces 10a, 20a of the films 10, 20 or the like. For example, when knurling is provided at both end portions of the film or the like 10, 20, both end portions (knurled portions) provided with knurling, and a film sandwiched between the knurled portions are provided. The central portion of the width direction of 20, the portion used, the contact surface pressure is applied in a different manner. In the graph of Fig. 6, as indicated by a broken line, a contact surface pressure in a range of 0.01 MPa or more and 0.30 MPa or less is applied to the knurled portion. Further, in the graph of Fig. 6, as shown by the solid line, the contact surface pressure in the range of 0.01 MPa or more and 0.10 MPa or less is applied to the use portion. In any of the knurled portion and the used portion, the contact surface pressure applied to the portion of the film having a smaller winding length in Fig. 6 is the highest. Further, as the winding length of the film in Fig. 6 becomes larger, the contact surface pressure applied to the film portion tends to decrease. Here, the winding length of the film is the length of the film roll from the end portion of the film on the core 23 side, which indicates the amount of the film portion, and the portion of the film having a small winding length means the vicinity of the core 23 The film portion is separated from the core 23 as the winding length of the film becomes larger.

The contact surface pressure applied to the film portion in the vicinity of the winding core 23 tends to increase as the film becomes elongated. For example, in the graph of Fig. 6, as shown by the solid line, in the range of the core 23 of the elongated film having a length of less than 4000 m (from 0 to 2000 m from the core), the application is in the range of 0.05 MPa to 0.10 MPa. The degree of contact surface pressure. Therefore, conventionally, when the film is shorter than 2000 m, no major problem occurs. However, if the length of the film is in the range of 2000 m or more and 10000 m or less, and the film is long, adhesion, recess, wrinkles, and core side transfer failure are likely to occur. tendency.

Further, conventionally, for example, the thickness of the film is 10 μm or more and 60 μm or less. In the case where the film is thin, when the film core 23 is wound up to form a film roll, adhesion, a concave portion, a wrinkle, and a core side transfer tend to occur. In addition, when the elastic modulus of the film is, for example, in the range of 1.0 GPa or more and 4.0 GPa or less, the elastic modulus of the film is low, and when the film is wound up on the core to form a film roll, adhesion and concave portions are likely to occur. The tendency of wrinkles and core side transfer failure.

In the film roll 22, as in the case shown in Fig. 4, the film faces 10a, 20a are in contact with each other in the winding overlapping portion of the film or the like 10, 20. Further, the contact surface pressure as described above is applied between the wound overlapping portions of the film faces 10a, 20a.

When the film or the like 10 and 20 are wound into a film roll shape, the two film faces 10a and 20a which are opposed to each other are partially prevented from coming into direct contact with each other by the protrusions 15 similarly to the overlap of the two films 10 and 20, and the like. Therefore, the mutual attachment of the overlapping portions of the films 10, 20 is reduced.

In the film roll 22, the static friction coefficient of the portion of the film surface 10a, 20a where the contact surface pressure is in the range of 0.05 MPa or more and 0.10 MPa or less is 1.2 or less. Therefore, slippage occurs between the overlapping portions of the films 10, 20, and thus the occurrence of adhesion, recess, wrinkles, and core side transfer failure is reduced. Further, in the film roll 22, as described above, even if the film or the like 10, 20 is long, the thickness is thin, and the elastic modulus is low, the occurrence of adhesion, recess, wrinkles, and core side transfer failure is reduced. The static friction coefficient of the portion having a contact surface pressure of 0.05 MPa or more and 0.10 MPa or less is preferably 1.0 or less, and the static friction coefficient of the portion having a contact surface pressure of 0.05 MPa or more and 0.10 MPa or less is 0.9 or less. good.

The film 10 is produced from the first dope 41 and the second dope 42 by a solution film forming apparatus 30 (see Fig. 7) which will be described later. The first dope 41 forming the film main body 12 is a first dope composition containing a liquid phase of a cellulose sulphate as a polymer, an additive, and a solvent. Cellulose The compound and the additive are contained in the first dope composition as a solid. The cellulose halide is dissolved in a solvent, and the additive is dispersed in the solvent without being dissolved in the solvent. The ratio of the cellulose halide to the additive in the first dope 41 is the same as the ratio of each component of the film main body 12.

The second dope 42 forming the surface layer 13 is a second dope composition containing a solid matter and a solvent similar to the first dope 41, and further containing a liquid phase of the fine particles 14 as solid matter. The ratio of the cellulose halide, the additive, and the fine particles 14 in the second dope 42 is the same as the ratio of each component of the surface layer 13. The ratio of the components constituting the first dope 41 and the second dope 42 is determined in consideration of the concentration of the solid matter of each dope and the ratio of the components constituting the film main body 12 and the surface layer 13, respectively.

Here, the fine particles 14 are generally used as a raw material of the second dope 42 in a state of being dispersed in a dispersion of the dispersant, and are used to prepare the second dope 42. Here, since the dispersion state of the fine particles 14 in the second dope 42 is substantially the same as the dispersion state of the fine particles 14 in the dispersion liquid, the dispersion state of the fine particles 14 in the second dope 42 is described as being used for preparation. The particles 14 of the second dope 42 have the same dispersion state in the dispersion.

In the second dope 42 , the fine particles 14 are dispersed in the form of secondary particles. The content ratio N (0.7) [unit: %] of the fine particles 14 having the secondary particle diameter r2 of 0.7 μm or more to the total number of the fine particles 14 contained in the second concentrated liquid 42 is preferably 30% or more, and preferably contains a ratio N. (0.7) is more preferably 50% or more. The second dope 42 forming the surface layer 13 contains the fine particles 14 having a secondary particle diameter of 0.7 μm or more, and as described above, the surface layer 13 is formed with desired protrusion densities D(H) and Dk(Hk). A desired protrusion 15 of height H, Hk. Therefore, with respect to the film 10 produced using the second dope 42 described above, when the film 10 is superposed, the adhesion of the films 10 is reduced, and the film surface 10a is provided with slidability.

Here, the secondary particle diameter indicating the diameter of the secondary particles of the fine particles 14 is defined as follows R2. When the shape of the secondary particles is spherical or nearly spherical, the diameter when the secondary particles are approximated to a spherical shape is set as the secondary particle diameter r2. When the shape of the secondary particle is an ellipsoid, the length of the major axis is set to the secondary particle diameter r2, and when the ellipsoid is approximated, the length of the major axis when the secondary particle is approximated to the ellipsoid is set as the secondary particle diameter. R2. The secondary particle diameter r2 of the fine particles 14 contained in the second dope 42 is obtained as follows. The second dope 42 is extended in a thin manner on a flat surface, and when the surface is observed by, for example, scanning with a scanning electron microscope (SEM) to a magnification of 3000 times, a surface observation view of each secondary particle can be obtained. image. For the surface observation images of the respective secondary particles, the fitting is performed by a circle approximation or an elliptical approximation. When the circle approximation is used, the value of the diameter is set to the secondary particle diameter r2, and when the ellipse is approximated, the length of the major axis is set to the secondary particle diameter r2.

The solvent 53 used in the first dope 41 and the second dope 42 is a mixture of dichloromethane, methanol and butanol. Further, in the present embodiment, the solvent is used, but any other solvent which is generally used for producing a solution of a cellulose halide film can be used. Further, when the polymer components of the film main body 12 and the surface layer 13 are not made into cellulose mash, the solvent 53 used in the first dope 41 and the second dope 42 is determined depending on the polymer component to be used.

The solution film for producing the film 10 is carried out, for example, in the solution film forming apparatus 30 of Fig. 7. The solution film forming apparatus 30 includes a dope preparation device 31, a casting device 32, a tenter 35, a roll drying device 36, and a winding device 37 in this order from the upstream side (see Fig. 8 for details). In addition, the detailed description of the winding device 37 will be described later.

The dope preparation device 31 is used to produce the first dope 41 and the second dope 42 described above. The dope preparation device 31 may be disposed outside the solution film forming apparatus 30 instead of the solution film forming apparatus 30. At this time, the produced first concentrated liquid 41 and second concentrated liquid 42 are temporarily stored in a storage container or the like. The dope preparation device 31 includes a dissolution portion 43, a mixing portion 46, a dispersion portion 47, and filtration Departments 48, 49.

When the cellulose halide 52 and the solvent 53 are supplied, the dissolved portion 43 is mixed and heated, stirred, or the like. Thereby, a liquid raw material dope 54 (raw material dope preparation process) in which the cellulose halide 52 is dissolved in the solvent 53 is produced. When a part of the raw material concentrate 54 and the additive 59 are mixed and supplied, the filter unit 48 filters the first concentrated liquid 41.

When the cellulose halide 52, the solvent 53 and the fine particles 14 are supplied, the mixing unit 46 mixes and stirs them to obtain a liquid mixture (mixture preparation process). The dispersion portion 47 is disposed downstream of the mixing portion 46. When the liquid mixture is supplied from the dispersion portion 47, ultrasonic waves are applied to the mixture, and the fine particles 14 are dispersed in the mixture to obtain a fine particle dispersion liquid 58 (fine particle dispersion process). Further, instead of applying ultrasonic waves, a ball mill may be used in the dispersion portion 47. When the fine particle dispersion liquid 58 obtained by the dispersion unit 47, the other portion of the raw material dope 54 and the additive 59 are mixed and supplied, the filter unit 49 mixes the mixture (mixing process) and filters it to form the second dope 42. (Filter process).

The casting device 32 is used to form the film 10 from the first dope 41 and the second dope 42. The casting device 32 includes a conveyor belt 62, a first roller 63, and a second roller 64. The conveyor belt 62 is a cyclic casting support formed in a ring shape and made of SUS. The conveyor belt 62 is wound around the circumferential surfaces of the first roller 63 and the second roller 64. At least one of the first roller 63 and the second roller 64 has a driving portion (not shown) that is rotated in the circumferential direction by the driving portion. By this rotation, the conveyor belt 62 that is in contact with the circumferential surface is conveyed, and by this conveyance, the conveyor belt 62 circulates and continuously travels in the longitudinal direction.

A casting die 65 that discharges the first dope 41 and the second dope 42 is provided above the conveyor belt 62. The first concentrated liquid 41 and the second concentrated liquid 42 are continuously discharged from the casting die 65 to the conveying belt 62 in the conveying state, and the first concentrated liquid 41 and the second concentrated liquid 42 are superposed on each other in the conveying belt 62. The upper casting is performed to form a casting film 66. Further, the first dope 41 is discharged from the discharge port 65a of the casting die 65 in a state of being sandwiched between the second dope 42.

Each of the first roller 63 and the second roller 64 includes a temperature controller (not shown) that controls the temperature of the circumferential surface. The temperature of the conveyor belt 62 is adjusted by controlling the temperatures of the respective peripheral surfaces of the first roller 63 and the second roller 64.

The so-called liquid bead, which is the first dope 41 and the second dope 42 from the casting die 65 to the conveyor belt 62, is provided with a decompression chamber (not shown) upstream of the traveling direction of the conveyor belt 62. The decompression chamber sucks the atmosphere of the first concentrated liquid 41 and the upstream side region of the second concentrated liquid 42 to decompress the region.

After the casting film 66 is hardened to the extent that it can be conveyed to the tenter 35, it is peeled off from the conveyor belt 62 in a state containing the solvent 53. In the case of the dry casting method, the solvent content is in the range of 10% by mass or more and 100% by mass or less, and in the case of the cooling and casting method, the solvent content is in the range of 100% by mass or more and 300% by mass or less. get on. The dry casting method is a method in which the casting film 66 is mainly hardened by drying, and the cooling casting method is a method in which the casting film 66 is mainly gelated by cooling to be hardened. In addition, in the present specification, the solvent content is determined by setting the mass of the film 10 in a wet state to X and the mass after drying the film 10 to Y, and determining it by {(XY)/Y}×100. The value of the so-called dry basis.

At the time of peeling, the film 10 is supported by a peeling roller (hereinafter referred to as a peeling roller) 70, and the peeling position at which the casting film 66 is peeled off from the conveyor belt 62 is kept constant. When the conveyor belt 62 is circulated and returned from the stripping position to the casting position where the first dope 41 and the second dope 42 are cast, the new first dope 41 and the second dope 42 are again cast.

It is also possible to face the casting surface of the casting belt 62 which forms the casting film 66. An air supply duct (not shown) is provided. The air supply duct discharges the gas to promote drying of the passing cast film 66.

The casting film 66, which is stripped by the stripping roller 70, that is, the film 10 is guided to the tenter 35. The tenter 35 holds the side portions of the film 10 with the holding member 71 while promoting the drying of the film 10. As the holding member 71 of the tenter 35, a clip, a pin, or the like is used. The clip holds the film 10 by sandwiching the film 10 and the pin through the film 10 in the thickness direction.

The tenter 35 holds the film 10 by the holding member 71 and conveys it in the longitudinal direction while imparting a tension in the width direction to enlarge the width of the film 10. The tenter 35 is provided with a duct 72 for supplying a dry gas to the vicinity of the film 10. The film 10 is conveyed while promoting drying by the drying gas from the conduit 72, and the width is changed by the holding member 71 at a predetermined timing.

The roller drying device 36 is used to dry the film 10 in a conveyed state. The roller drying device 36 includes a plurality of rollers 73, an air conditioner (not shown), and a chamber (not shown) arranged in the conveying direction of the film 10. Among the plurality of rollers 73, there is a driving roller that rotates in the circumferential direction, and the film 10 is conveyed downstream by the rotation of the driving roller. The air conditioner sucks the atmosphere inside the chamber, adjusts the humidity and temperature of the gas to be sucked, and the like, and then feeds the gas into the chamber again. Thereby, the temperature, humidity, and the like inside the chamber are kept constant. A knurling device (not shown) is provided between the roller drying device 36 and the winding device 37 (see Fig. 8 for details), and embossing (knurling) is performed on both end portions in the width direction of the film. In addition, even if there is no knurling device, it does not affect the present invention. The winding device 37 (see Fig. 8 for details) winds up the film 10 supplied from the roll drying device 36 into a roll shape. Further, a cooling chamber (not shown) may be provided between the roller drying device 36 and the winding device 37 (see Fig. 8 for details). The cooling chamber will pass through the interior Film 10 was cooled to room temperature prior to coiling.

The solution film forming apparatus 30 is an example of an embodiment of the present invention, and may be another solution film forming apparatus. For example, instead of the conveyor belt 62, a roller (not shown) that rotates in the circumferential direction may be used as the casting support. In the case of cooling the casting method, it is often the case that the drum is used as a casting support. Further, a tenter (not shown) having the same configuration as the tenter 35 may be provided between the tenter 35 and the roller drying device 36.

As shown in Fig. 8, the winding device 37 is provided with a take-up shaft 81, a core holder 82, a turret 83, guide rollers 86, 87, a dancer roller 88, an encoder 91, a take-up motor 92, and a displacement mechanism 93. And controller 94.

The take-up shaft 81 is attached to the turret 83 by a cantilever support mechanism. The cantilever support mechanism is a mechanism that supports only one end of the take-up shaft 81. The outer circumferential surface of the take-up shaft 81 is fitted to the core grip portion 23a (see FIG. 5), and the winding core 23 is rotatably attached to the take-up shaft 81. The winding core 23 attached to the take-up shaft 81 sandwiches both end portions by the core holder 82. A winding motor 92 is coupled to one end of the take-up shaft 81, and is configured to rotate the take-up shaft 81. By this rotation, the film 10 which is rotated by the winding core 23 and wound in a roll shape is wound up on the circumferential surface of the winding core 23, whereby the film roll 22 can be obtained.

The guide rolls 86, 87 and the dancer roller 88 guide the film 10 in the conveying direction (X direction of Fig. 8). An encoder 91 is coupled to the guide roller 87, and an encoder pulse signal is transmitted to the controller 94 each time the guide roller 87 rotates at a constant rotation angle. Further, the dancer roller 88 moves a portion of the transport path of the film 10 in a direction perpendicular to the film surface 10a (Z direction in Fig. 8) by the displacement mechanism 93, thereby adjusting the take-up tension of the film 10. Further, a tension sensor for measuring the take-up tension of the film 10 may be provided on the guide roller 87.

The controller 94 is connected to the encoder 91, the take-up motor 92, and the displacement mechanism 93. The controller 94 receives the encoder pulse signal transmitted from the encoder 91 to manage the winding length (winding length) of the film 10. Also, the controller 94 controls the take-up motor 92 to control the take-up speed. Further, the controller 94 controls the take-up tension of the film 10 by the displacement mechanism 93.

The action of the above configuration will be described. When the cellulose halide 52 and the solvent 53 are sent to the dissolving portion 43, the raw material dope 54 (raw material dope preparation process) is prepared by heating, stirring, or the like. Before a part of the raw material dope 54 is guided to the filter unit 48, the additive 59 is added, and the mixture is mixed with the additive 59, and filtered by the filter unit 48 to become the first dope 41.

When the fine particles 14, the cellulose halide 52, and the solvent 53 are guided to the mixing portion 46, they are mixed by the mixing portion 46 and stirred to obtain a liquid mixture (mixture preparation process). Here, as described above, the content ratio N (0.7) of the fine particles 14 contained in the second dope 42 is preferably 30% or more. This mixture is sent from the mixing portion 46 to the dispersion portion 47. The fine particles 14 in the mixture are dispersed in the mixture by the dispersion portion 47, thereby obtaining a fine particle dispersion liquid 58 (fine particle dispersion process). A fine particle dispersion liquid 58 is added to another portion of the raw material dope 54, and an additive is added thereto, and is guided to the filter portion 49 for mixing (mixing process), and filtered by the filter portion 49 to form a second dope 42. (Filter process).

The first dope 41 and the second dope 42 are continuously guided to the casting die 65, and are continuously discharged from the discharge port 65a. The second concentrated liquid 42, the first concentrated liquid 41, and the second concentrated liquid 42 are sequentially stacked on the conveyor belt 62 to form a casting film 66. The casting film 66 formed on the traveling conveyor belt 62 is self-supporting, and is then peeled from the conveyor belt 62 in a state containing the solvent 53 to form the film 10.

The film 10 is sent to the tenter 35 to pass through the atmosphere of the dry gas supplied from the duct 72 by the state in which the holding member 71 restricts the width. Thereby, the drying of the film 10 is promoted. The film 10 from the tenter 35 is guided to the roll drying device 36 and dried during the passage through the chamber (not shown) of the roll drying device 36. When the knurling device is provided, the dried film 10 is guided to a knurling device (not shown), and embossing (knurling) is performed on both end portions of the film 10 in the width direction. The dried film 10 is guided to a take-up device 37.

In the winding device 37, the winding length of the film 10, the winding rotation speed, and the winding tension of the film 10 are controlled by the controller 94, and the film 10 is wound up in a roll shape on the circumferential surface of the winding core 23 to become a film. Volume 22 (rolling process). The film roll 22 is pulled out of the film 10 by, for example, a drawing device (not shown) for pulling out the film 10, and the drawn film 10 is cut into a film by a cutting device (not shown) which is cut out in a sheet form. (not shown) (cut out process) for use. In the film sheet thus obtained, the influence of the adhesion of the film which is overlapped in the film roll is reduced.

The mass ratio Wp [unit: mass%] of the fine particles 14 to the cellulose halide 52 in the second dope 42 and the content ratio N (0.7) with respect to the fine particles 14 and the protrusion density D (30) on the film surface 10a. There is a correlation between [unit: one/mm ² ]. The protrusion density D (30) increases as the mass ratio Wp and the content ratio N (0.7) increase. Here, the mass ratio Wp is the ratio defined by (total mass of particles added to the dope) / (total mass of cellulose halide used in the dope). Further, the content ratio N (0.7) and the protrusion density D (30) were determined by the measurement methods described in the examples below. Further, the protrusion density Dk (30), the protrusion density D (40), the protrusion density Dk (40), and the like also have an increase in the mass ratio Wp and the content ratio N (0.7) similarly to the protrusion density D (30). And the tendency to increase.

As an example, if the mass ratio Wp is set to 0.1 mass% or more and 0.3 mass In the range of % or less, when the primary particle diameter r1 of the particles is in the range of 12 nm or more and 20 nm or less, as shown in Fig. 9, it is understood that the protrusion density D (30) is substantially increased as the content ratio N (0.7) is increased. increase. A line U1 indicating the correlation between the ratio N (0.7) and the protrusion density D (30) is shown in Fig. 9. Further, when the mass ratio Wp is decreased, the straight line U1 is shifted to the lower side (one side of the decrease in the projection density D (30)) in FIG. 9, and if the mass ratio Wp is increased, the straight line U1 is upward in the ninth diagram. The side (the side of the protrusion density D (30) increases) is offset. Further, it is not limited to the protrusion density D (30), and the protrusion density D (40) and the protrusion density D (50) also increase as the mass ratio Wp and the content ratio N (0.7) increase.

In the present embodiment, three layers of the film 10 having the plural layer structure are produced. However, as described above, the present invention also has an effect on a film having a single layer structure. Further, in the present embodiment, the film 10 having the three-layer structure composed of the film main body 12 and the pair of surface layers 13 is produced, but the film obtained by the present invention is not limited thereto. For example, it may be four or more layers by layer casting, coating, or the like. Further, in the case of producing a film having a single-layer structure, the content ratio N (0.7) of the fine particles 14 is preferably 30% or more. Further, the projection density D (30) of the film surface 10a of the produced film is in the range of 10 ⁴ /mm ² or more and 10 ⁶ /mm ² or less, and the projection density Dk of the film surface 10a after the saponification treatment is performed (30). In the same manner as before the saponification treatment, it is in the range of 10 ⁴ /mm ² or more and 10 ⁶ /mm ² or less.

Hereinafter, four examples related to the present invention will be described.

[Example 1]

As Example 1, 17 experiments 1-A to 1-Q were carried out. In the first embodiment, a dispersion of three kinds of fine particles 14 each having a trade name of R972, NX90S, and RX200 (all manufactured by Nippon Aerosil Co., Ltd.) was used. Here, the dispersion liquid of the three kinds of fine particles 14 is summarized in Table 1 below. In the dispersion liquid of each product name described in each column of the "dispersion liquid" in Table 1, the materials constituting the fine particles 14 are shown in the column of "fine particles", and the components constituting the dispersing agent are shown in the column of "dispersing agent". The substance, the concentration of the fine particles 14 in the dispersant [unit: mass%] is shown in the column of "particle concentration", and the average value of the primary particle diameter r1 of the fine particles 14 is shown in the column of "primary particle diameter" [unit: nm ], the average value [unit: μ m] of the secondary particle diameter r2 of the fine particles 14 is shown in the column of "average particle diameter of secondary particle", and the particle 14 is shown in the column of "content ratio N (0.7)". Contains the ratio N (0.7) [unit: %]. Further, the "fine particles" and the "dispersant" were the same in the three kinds of dispersions, so the columns in Table 1 were separately combined. The ratio of CH ₂ Cl ₂ :CH ₃ OH in the column of "dispersant" is the ratio by mass.

Here, the secondary particle diameter r2 of the fine particles 14 is based on the definition described in the above embodiment, and as described above, the surface is observed by SEM magnification to 3000 times, and the secondary particle diameter is obtained for each of the fine particles 14. The particle size distribution of the fine particles 14 is obtained based on the result of the secondary particle diameter r2 obtained for each of the fine particles 14, and the median diameter is determined based on the particle diameter distribution, and the median diameter is determined. The average value of the secondary particle diameter r2 is set. Further, the content ratio N (0.7) with respect to the fine particles 14 is obtained from the particle size distribution of the fine particles 14. Further, the content ratio N (0.7) of the fine particles 14 obtained here is the content ratio N (0.7) after the addition to the dope.

The trade names of the dispersion liquid of the fine particles 14 used in each experiment are shown in the column of "dispersion liquid" of "fine particles" in the column of each example of Table 2. Further, the mass ratio Wp of the fine particles 14 to the cellulose halide 52 is shown in the "mass ratio" column of "fine particles" in each experiment of Table 2. Further, the experiment 1-L was compared with the comparative experiment of the present invention, and no dispersion was added to the 1-L, so the column of "dispersion" in Table 2 was indicated as "-".

Further, the solid matter other than the fine particles 14 contained in the dope for each experiment was set to any one of the following solids A to C. In either experiment, the same type of solids were used in all three layers of dope. The solid matter other than the fine particles 14 used in each experiment is shown in the column of "solid type" in each experiment of Table 2. In addition, the ratio expressed by the unit of the mass part is the ratio of the whole of the solid matter derived from the raw material dope 54 and the solid matter other than the fine particles 14 derived from the fine particle dispersion liquid 54 in the above embodiment.

Solid A is composed of the components shown below. The film 10 produced using the solid A had an average elastic modulus in the longitudinal direction and the width direction of 4.5 GPa.

[solids A]

Ultraviolet absorber TINUVIN (registered trademark) 928 (manufactured by BASF Japan Ltd.) 2.0 parts by mass

Here, the cellulose triacetate has a degree of substitution of 2.86, a viscosity average degree of polymerization of 306, a water content of 0.2% by mass, and a viscosity of 6% by mass in a dichloromethane solution of 310 mPa. s powder. Sucrose benzoate and sucrose acetate isobutyrate plasticizer. Also, TINUVIN (registered trademark) 928 is 2-(2H-benzotriazol-2-yl)-6-(1-methyl-1-phenylethyl)-4-(1,1,3,3- Tetramethylbutyl)phenol is the main component.

The solid matter B is composed of the components shown below. The film 10 produced using the solid material B had an average elastic modulus in the longitudinal direction and the width direction of 3.0 GPa.

[solids B]

Ultraviolet absorber TINUVIN (registered trademark) 928 (manufactured by BASF Japan Ltd.) 2.0 parts by mass

The solid matter C is composed of the components shown below. The film 10 produced using the solid material C had an average elastic modulus in the longitudinal direction and the width direction of 3.0 GPa.

[solids C]

Acrylic polymer 100.0 parts by mass

Further, a mixture of the formulations shown below was used for the solvent contained in the dope of each experiment.

[solvent]

In either experiment, the dope was produced using the dope preparation device 31 shown in Fig. 7 above. Here, the dope to which the fine particles 14 are added, which will be described later, is produced by the same method as the second dope 42, and the dope to which the fine particles 14 are not added is produced by the same method as the first dope 41. Further, in any of the experiments, the concentration of the solid matter forming the dope of the film main body 12 was 22%, and the solid matter concentration of the dope forming the surface layer 13 was 19%. Further, in any of the experiments, the casting film 66 was formed by the casting device 32 shown in Fig. 7. The dope forming the film main body 12 is sandwiched in the dope forming the surface layer 13, thereby forming the casting film 66 in a state in which the three layers are overlapped. Further, the casting film 66 is peeled off to form the film 10. Thereafter, in the solution film forming apparatus 30 of Fig. 7, the same processing as that of the above embodiment is performed by each device provided downstream of the casting device 32.

Here, regarding the experiments 1-A to 1-E and 1-J to 1-Q, the fine particles 14 were added to all the three layers of the dope. On the other hand, regarding the experiment 1-F~1-I, the fine particles 14 were added only to the dope in which the surface layer 13 was formed. The layers in which the dope of the microparticles were added in each experiment are shown in the column of "addition layer" of "fine particles" in each experiment of Table 2. Here, an example in which the fine particles 14 are added to all of the three layers of the dope is referred to as "full layer", and an example in which the fine particles 14 are added only to the dope in which the surface layer 13 is formed is referred to as "surface layer".

With respect to each of the films 10 to be produced, the total density (total protrusion density D [unit: piece/mm ² ]) of the protrusions 15 on the film surface 10a and the height before and after the saponification treatment were 30 nm or more, respectively, by the following method. The density of the protrusions 15 (the protrusion density D (30) [unit: piece / mm ² ], Dk (30) [unit: piece / mm ² ]).

The observed image was obtained by observing in a direction substantially perpendicular to the film surface 10a of each of the produced films 10 (before the saponification treatment). This observation was carried out using a scanning probe microscope (SPA400, manufactured by SII Nano Technology Inc.) in an AFM (Atomic Force Microscope) mode at a range of 100 μm × 100 μm . Hereinafter, the observed image obtained here is referred to as an AFM image. In the AFM image, the brightness of the pixel corresponding to the portion is displayed at a higher height from the surface of the film surface 10a at the observed portion. As an example of the AFM image, an AFM image relating to the film 10 produced in Experiment 1-D is shown in Fig. 10.

According to the nature of the AFM image in which the brightness becomes higher with the height of the protrusion, when the predetermined brightness is set to a threshold value in the AFM image and the binarization processing is performed, the predetermined height can be separated from the surface of the film surface 10a. The part. With this, for each AFM image, a binarization process in which a portion protruding from the surface of the film surface 10a by 10 nm or more is made into brightness and the other portions are made dark luminance is separated. Here, an example of an image obtained by performing the binarization processing on the AFM image obtained in Experiment 1-D is shown in FIG.

In an image obtained by binarizing the luminance at a height of 10 nm as a threshold value, each part of the brightness (for example, an island of each gray in FIG. 11) is recognized as having a height of 10 nm or more. The protrusion is detected. The number of protrusions having a height of 10 nm or more is obtained by counting the number of portions that become the brightness. Further, the number of the protrusions is multiplied by 100 and converted into the number of protrusions per 1 mm ² as the total protrusion density D1 of the portion in the region where the AFM image is acquired. In each experiment, a plurality of AFM images were acquired, and a plurality of local total protrusion densities D1 were determined, and the arithmetic mean of these was set as the total protrusion density D in each experiment. The total protrusion density D is shown in the column of "total protrusion density D" in each experiment of Table 3. In addition, the effective number is a value of two bits in the column of "total protrusion density D".

The threshold value when the binarization process is performed in the method of determining the total protrusion density D is changed to a brightness when the film surface 10a is protruded by 30 nm or more, and the other experiments are performed by the same method as the total protrusion density D. The protrusion density D (30). Here, in the Fig. 12, an example of an image obtained by performing binarization processing on the AFM image obtained in Experiment 1-D using the luminance at a height of 30 nm as a threshold value is shown. The protrusion density D (30) is shown in the column of "protrusion density D (30)" in each experiment of Table 3. In addition, the effective number is a value of 3 bits in the column of "protrusion density D (30)".

After the saponification treatment of each of the produced thin films 10, the process of obtaining the AFM image, the binarization process, and the process of obtaining the number of protrusions, the protrusion density Dk in each experiment was obtained by the same method as described above. (30). The protrusion density Dk (30) is shown in the column of "protrusion density Dk (30)" in each experiment of Table 3. Further, the effective number is a value of 3 bits in the column of "protrusion density Dk (30)".

For each of the films 10 before and after the saponification treatment in each experiment, the degree of reduction of the adhesion was evaluated as follows. First, each of the films 10 was cut into a square of 7 cm × 7 cm by overlapping three sheets. Then, the film was superimposed for 24 hours under the conditions of a temperature of 25 ° C and a humidity of 50%, and then placed in an environment of a temperature of 40 ° C and a humidity of 20% in a state of overlapping three sheets. Then, after placing a weight of 5 kg on each of the three superposed films 10 and leaving it for 24 hours, the ratio S [unit: %] of the contact area of the film 10 to the contact area of the film 10 was determined. The ratio S of the obtained attachment area was evaluated in the following four stages of A to D. The evaluation results are shown in the column of "attachment evaluation" in each experiment of Table 3. The evaluation before the saponification treatment is shown in the column "before the saponification treatment", and the saponification treatment is shown in the column after "saponification treatment". After the evaluation. If the adhesion evaluation is among A, B, and C, the film 10 is within the range allowed in actual use.

A: less than 20%

B: 20% or more and less than 30%

C: 30% or more and less than 40%

D: 40% or more

For each film 10 before the saponification treatment in each experiment, a haze meter (NDH-5000, Nippon Denshoku Industries Co. Ltd.) was used, and the haze was measured in accordance with JIS-K-7105. The measurement results of the haze are shown in the "haze" column in each experiment of Table 3.

The following are known from Tables 2 and 3. The tendency was observed that although some deviation occurred, the protrusion density D (30) substantially increased as the content ratio N (0.7) of the dispersion and the mass ratio Wp increased. Further, it is understood that the haze of the produced film is suppressed to be lower when the layer is formed in the surface layer than when the layer of the fine particles 14 is added.

Further, no correlation was observed between the total protrusion density D and the results of the evaluation of the adhesion before the saponification treatment. For example, in the experiments 1-C, 1-F, 1-N, 1-P, 1-Q, the total protrusion density D was 90,000 / mm ² , but the adhesion evaluation before the saponification treatment was A, A, respectively. , B, C, C, have produced a big difference. On the other hand, a correlation was observed between the protrusion density D (30) and the result of the evaluation of the adhesion before the saponification treatment. In the experiments 1-A to 1-K in which the projection density D (30) was 20,000 / mm ² or more, the evaluation before the saponification treatment was A. In the experiment 1-O in which the protrusion density D (30) was in the range of 16,000 pieces/mm ² or more and less than 20,000 pieces/mm ² , the adhesion before the saponification treatment was evaluated as B. Evaluation of adhesion before saponification treatment in experiments 1-M, 1-N, 1-P, 1-Q in the range where the protrusion density D (30) is 10000 / mm ² or more and less than 16000 / mm ² They are C, B, C, and C respectively. Further, in Experiment 1-L in which the protrusion density D (30) was less than 10,000 / mm ² , the adhesion before the saponification treatment was evaluated as D.

Further, a correlation was observed between the protrusion density Dk (30) and the result of the evaluation of the adhesion after the saponification treatment. In the experiments 1-D, 1-E, 1-G~1-K in which the protrusion density Dk (30) was 20,000/mm ² or more, the evaluation after the saponification treatment was A. In the experiments 1-B, 1-C, and 1-F in which the protrusion density Dk (30) was in the range of 10000 / mm ² or more and less than 20,000 / mm ² , the adhesion after the saponification treatment was evaluated as B. In the experiment 1-A, 1-L~1-Q in which the protrusion density Dk (30) was less than 10000 / mm ² , the adhesion after the saponification treatment was evaluated as D.

Further, in the experiments 1-N, 1-P, and 1-Q which were set to the same conditions except for the solid matter, in the experiments 1-P, 1-Q in which the solid materials B and C having a low film elastic modulus were used. The evaluation before the saponification treatment was C, which was lower than the evaluation evaluation B of the experiment 1-N using the solid A. On the other hand, in the experiments 1-G, 1-J, 1-K in which the protrusion density D (30) was also maintained under the same conditions except for the solid matter, the experiment 1-J, 1 in which the solids B and C were used. -K, attached The evaluation was A, which was the same result as the evaluation A of the experiment 1-G using the solid A. From this, it is understood that the use of the films of the solids B and C having a lower modulus of elasticity than the film using the solid A has a greater effect of reducing the adhesion by increasing the protrusion density D (30).

[Embodiment 2]

In Example 2, each film 10 before the saponification treatment having a thickness of 40 μm which was produced in the experiments 1-A, 1-C, 1-D, 1-G, and 1-I~1-O of Example 1 was used. Come on. The static friction coefficient when the contact surface pressures were 0.01 MPa, 0.03 MPa, 0.05 MPa, 0.07 MPa, and 0.10 MPa was determined for each film 10 by the method described below. The static friction coefficient at the time of each contact surface pressure is shown in the column of "static friction coefficient" in each experiment of Table 4.

The Tengxiong universal testing machine RTG-1250 manufactured by A&D Co., Ltd. was used for the measurement of the static friction coefficient. In addition, "Teng Xi Long" is "TENSILON" (registered trademark). Here, the force sensor 108 (refer to Fig. 13) used in the testing machine sets the range of 50N to 500N to a specification of a suitable range. As a measuring method for measuring the static friction coefficient using the testing machine and the force sensor, the same method as "JIS K7125 plastic film and sheet friction coefficient test method" was used. Hereinafter, a method of measuring the static friction coefficient for an arbitrary contact surface pressure will be specifically described.

In order to measure the static friction coefficient, as an initial arrangement (initial arrangement) before the start of the measurement, the arrangement of the two test pieces overlapped as shown in Fig. 13 was performed. First, the test piece which is fixed to one side of the fixed table, that is, the fixed side test piece 102, and the test piece which is one side of the sliding movement after the start of the measurement, that is, the slide side test piece 104, is prepared. Each of the films 10 was subjected to humidity conditioning for 1 hour or more in an environment of 25 ° C and 60% RH. The fixed side test piece 102 and the sliding side test piece 104 are both separated from the film side of the film and the film side of the outer side at the time of winding, and are capable of distinguishing the web direction and The manner in which the width direction of the sheet is cut is separately cut out. Here, the fixed side test piece 102 is cut into a substantially rectangular shape, and its size is set to be 200 mm or more in the sheet direction, and the length in the width direction of the sheet is 50 mm or more. Further, the sliding side test piece 104 is also cut into a substantially rectangular shape, and has a size of 50 mm or more in the sheet direction and a length of 50 mm or more in the width direction of the sheet.

On the upper surface of the substantially horizontal test piece fixing table 101, the fixed side test piece 102 is fixed so as to overlap the film side on the inner side via the double-faced tape. On the fixed side test piece 102, the slide side test piece 104 prepared above is placed so that the film direction and the sheet width direction are substantially uniform so as not to be fixed so as to face downward. On the sliding side test piece 104, the slide piece 105 is overlapped and fixed via a double-sided tape. A weight 106 is placed on the slider 105. Here, the slide piece 105 is a surface that can be brought into surface contact with the slide side test piece 104 and is not deformed by the weight 106. Further, the contact area between the slide piece 105 and the slide side test piece 104 was set to 4 cm ² . Further, the mass of the weight 106 is in the range of 400 g or more and 4.0 kg or less, and the mass of the weight is determined by using the formula of the contact surface pressure described later from each contact surface pressure as the setting condition. Moreover, the slide piece 105 is coupled to the force sensor 108 via the wire 107. One end of the wire 107 is attached to the side of the slide piece 105 perpendicular to the sheet direction, and the other end is connected to the force sensor 108. In order to adjust the direction of the tension applied to the slide piece 105 and the direction of the tension applied to the force sensor 108, the pulley 109 is appropriately disposed on the wire 107.

After performing this initial configuration, wait for a certain amount of time to stabilize the initial configuration. Thereafter, the force sensor 108 is continuously moved at a speed of 1000 mm/min., thereby continuously applying tension to the wire 107. Thus, the force in the direction of the sheet is continuously applied to the slider 105. When the force is applied to the slide piece 105, the slide piece 105 is integrated with the slide side test piece 104 and the weight 106, and moves while sliding on the fixed side test piece 102. Start moving at power sensor 108 During the period until the end of the movement, the amount of movement of the slide piece 105 with respect to the initial arrangement is measured as a displacement amount [unit: mm]. In the meantime, the force generated between the fixed side test piece 102 and the sliding side test piece 104 is measured as a frictional force [unit: N] by the force sensor 108. In the graph in which the horizontal axis takes the displacement amount and the vertical axis takes the frictional force, the change in the frictional force with respect to each displacement amount is plotted based on the above measurement result, for example, as shown in Fig. 14.

In Fig. 14, the frictional force (symbol: 114) indicated by the first maximum point 113 on the curve 112 is set as the static friction force [unit: N]. Here, the first maximum point 113 is the smallest of the maximum points on the curve 112. Using this static friction force, by the formula (static friction coefficient [unit: dimensionless]) = (static friction force [unit: N]) / (mass of weight 106 [unit: kg] × gravity acceleration g [unit: m / s ² ]) Determine the coefficient of static friction. Here, the gravitational acceleration g is about 9.8 m/s ² . Further, by the formula (contact surface pressure [unit: MPa]) = (mass of weight 106 [unit: kg] × gravitational acceleration g [unit: m / s ² ]) / (sliding side test piece 104 and sliding piece Contact area [unit: mm ² ] between 105) The contact surface pressure applied between the fixed side test piece 102 and the sliding side test piece 104 was determined. The contact surface pressure is changed by changing the mass of the weight 106 to determine the static friction coefficient with respect to each contact surface pressure.

Further, for each of the films 10, the film before and after the saponification treatment was wound into a roll shape by using a winding device 37, whereby the windability was evaluated. Here, the evaluation of the windability did not cause an evaluation of the degree of the concave portion, the wrinkles, and the core side transfer failure. The degree of occurrence of the concave portion, the wrinkle, and the core side transfer failure in the film roll 22 at the time of winding and the take-up property were evaluated in the following four stages of A to D. The evaluation results are shown in the "coilability" column in each experiment of Table 4.

A: No recesses and wrinkles are generated, and the area where the core side transfer failure occurs is less than 50 m.

B: The concave portion and the wrinkles are generated, and the generation area of the core side transfer failure is 50 m or more. And less than 100m

C: severe recesses and wrinkles are generated, and the generation area of the core side transfer failure is 100 m or more and less than 200 m.

D: Serious recesses and wrinkles are generated on the entire film, and the generation area of the core side transfer failure is 200 m or more.

As shown in Table 4, correlation was observed between the evaluation of the adhesion before the saponification treatment, the result of the static friction coefficient, and the evaluation of the take-up property before the saponification treatment. Further, as shown in Table 4, each of the films 10 before the saponification treatment of Experiments 1-A, 1-C, 1-D, 1-G, and 1-I~1-K is an example of the present invention, and the experiment 1-L The films before the saponification treatment of 1-M, 1-N, and 1-O are comparatively comparative to the present invention. An example of the test. In the film 10 of the experiment 1-A, 1-C, 1-D, 1-G, 1-I~1-K evaluated as A before the saponification treatment, the range is 0.05 MPa or more and 0.10 MPa or less. The static friction coefficient was 1.2 or less, and the coilability was evaluated as A. Further, in the film 10 of the experiment 1-O evaluated as B before the saponification treatment, the evaluation of the windability was B. Further, in the films of 1-M and 1-N of the test evaluated as C before the saponification treatment, the evaluation of the windability was C and B, respectively. In the film of Experiment 1-L evaluated as D before the saponification treatment, the evaluation of the windability was D. In the film evaluated for the windability of B, the maximum value of the static friction coefficient in the range of 0.05 MPa or more and 0.10 MPa or less is in the range of more than 1.2 and 1.3 or less. In the film of the evaluation of the windability of C, the maximum value of the static friction coefficient in the range of 0.05 MPa or more and 0.10 MPa or less is in the range of more than 1.3 and 1.4 or less. In the film of which the evaluation of the windability is D, the maximum value of the static friction coefficient in the range of 0.05 MPa or more and 0.10 MPa or less is more than 1.4.

In the film of the experiment 1-L to which the microparticles 14 were not added, the static friction coefficient between the films was as high as 1.40 at a contact surface pressure of 0.01 MPa. Therefore, it can be seen that it is impossible to slide between the films, and severe recesses and wrinkles are generated on the entire film, and the core side transfer failure occurs over a long area. Further, in the films of the experimental 1-M, 1-N, and 1-O in which the projection density D (30) is relatively low, when the contact surface pressure is 0.01 MPa, the static friction coefficient between the films is 0.8 or less, which is low. However, when the contact surface pressure is as high as 0.05 MPa, the static friction coefficient between the films is as high as 1.2 or more. Therefore, it can be seen that sliding between the partial films is impossible, and there is a possibility that a concave portion, a wrinkle, and a core side transfer failure may occur. On the other hand, each film 10 of the experiment 1-A, 1-C, 1-D, 1-G, 1-I-1-K in which the protrusion density D (30) is relatively high 20,000 / mm ² or more In the case where the contact surface pressure is as high as 0.05 MPa, the static friction coefficient between the films is kept low, being 0.8 or less, and even if the contact surface pressure is as high as 0.10 MPa, the static friction coefficient between the films is kept low, being 1.2 or less. Therefore, it can be seen that the sliding between the films can be suppressed, and the occurrence of the concave portion, the wrinkles, and the core side transfer failure can be suppressed.

Further, in addition to those shown in Table 4, each of the films 10 having a thickness of 20 μm and 40 μm which were produced in Examples 1-D, 1-J, and 1-K, respectively, were taken up before and after the saponification treatment. The roll was taken up and the take-up property was evaluated by the above method. As a result, A evaluation was obtained. In addition, in the film 10 having a thickness of 40 μm, the windability in which the film was wound up in a roll shape was confirmed after the transparent coating, and as a result, A was evaluated.

Here, the transparent coating means that a transparent hard coat layer is provided by coating the surface of the above film. As the transparent hard coat layer, an actinic ray curable resin or a thermosetting resin is preferably used. The actinic ray curable resin is a layer mainly composed of a resin which is cured by a crosslinking reaction by irradiation of actinic rays such as ultraviolet rays and electron beams. The actinic ray curable resin may be an ultraviolet curable resin or an electron beam curable resin, or may be a resin which is cured by irradiation with actinic rays other than ultraviolet rays and electron beams. Examples of the ultraviolet curable resin include an ultraviolet curable acrylic urethane resin, an ultraviolet curable polyester acrylate resin, and an ultraviolet curable epoxy acrylate resin.

Further, for each of the films 10 having a thickness of 40 μm which were produced in the experiments 1-A, 1-C, 1-D, 1-M, and 1-N, respectively, the gradual change contact was measured by the same method as described above. Static friction coefficient at face pressure. The results are shown in Fig. 15. Figure 15 shows the data of the static friction coefficient plotted on the horizontal axis as the contact surface pressure and the vertical axis as the static friction coefficient, and the plotted points are curve fitted. The curve C1 shown in Fig. 15 is based on the information on the film 10 of Experiment 1-M. Curve C2 is based on the experiment 1-N. Curve C3 is based on Experiment 1-A. Curve C4 is based on Experiment 1-C. Curve C5 is based on Experiment 1-D. In any of the films 10, In the region where the contact surface pressure is 0.005 MPa or less, the static friction coefficient takes a minimum value.

In the film of Experiment 1-M, as shown by the curve C1 in Fig. 15, the static friction coefficient is approximately monotonously sharp as the contact surface pressure increases until the contact surface pressure becomes 0.03 MPa or so. When the contact surface pressure is about 0.03 MPa, the static friction coefficient takes the maximum value, that is, about 1.40. When the contact surface pressure is about 0.03 MPa to about 0.10 MPa, the static friction coefficient is about 1.30 to 1.40. Further, in the film of Experiment 1-N, as shown by the curve C2 in Fig. 15, the static friction coefficient is substantially monotonous as the contact surface pressure increases until the contact surface pressure becomes about 0.05 MPa after the static friction coefficient is minimized. The ground is sharply increased. When the contact surface pressure is about 0.05 MPa, the static friction coefficient takes the maximum value, that is, about 1.30. When the contact surface pressure is about 0.05 MPa to about 0.10 MPa, the static friction coefficient is about 1.20 to 1.25. From this, it was found that in the films of the experiments 1-M and 1-N, the static friction coefficient could not be maintained at 1.2 or less even at a position where the contact surface pressure was high.

On the other hand, in the film of Experiment 1-A, as shown by the curve C3 of Fig. 15, the static friction coefficient was taken to be the minimum value until the contact surface pressure became about 0.05 MPa, and the static friction coefficient was roughly increased as the contact surface pressure was increased. It increases slowly monotonously, and when the contact surface pressure is about 0.05 MPa, the static friction coefficient becomes about 0.8. When the contact surface pressure is about 0.05 MPa to about 0.06 MPa, the static friction coefficient is greatly increased, and when the contact surface pressure is about 0.06 MPa, the static friction coefficient is about 1.10. When the contact surface pressure is about 0.06 MPa to about 0.10 MPa, the static friction coefficient becomes the maximum value, that is, about 1.05 to 1.10. From this, it was found that in the film of Experiment 1-A, the static friction coefficient could not be maintained at 1.2 or less even at a position where the contact surface pressure was high.

Further, in the film of Experiment 1-C, as shown by the curve C4 of Fig. 15, the static friction coefficient was taken to be the minimum value until the contact surface pressure became about 0.025 MPa, with the contact surface. When the pressure is increased, the static friction coefficient increases substantially monotonously. When the contact surface pressure is about 0.025 MPa, the static friction coefficient is about 0.80. When the contact surface pressure is about 0.025 MPa to about 0.05 MPa, the static friction coefficient is about 0.70 to 0.90, which is substantially constant. Further, in the film of Experiment 1-D, as shown by the curve C5 of Fig. 15, the static friction coefficient is taken to a minimum value and the contact surface pressure is about 0.025 MPa, and the static friction coefficient is substantially monotonously increased as the contact surface pressure increases. Slowly increase, when the contact surface pressure is about 0.025 MPa, the static friction coefficient takes the maximum value, that is, about 0.85. When the contact surface pressure is about 0.025 MPa to about 0.10 MPa, the static friction coefficient is about 0.60 to 0.70. From this, it was found that in the films of Experiments 1-C and 1-D, the static friction coefficient could not be kept extremely low even at a position where the contact surface pressure was high, that is, it could not be maintained at 0.9 or less.

[Example 3]

In the third embodiment of the present invention, the above-described solid material A was used, and the primary particle diameter r1 of the fine particles 14 and the addition amount thereof were changed to produce seven kinds of the film 10, and the height H of the protrusion which is effective for reducing the adhesion was confirmed. Among the seven types of films, the ratio S of the attachment area in the method of the above-described attachment evaluation was randomly selected from 0% to 50%.

The density (protrusion density D (10) [unit: mm/mm ² ]) of the protrusions having a height of 10 nm or more and the density of the protrusions having a height of 20 nm or more (protrusion density D (20)) were determined for each of the seven types of film 10 [Unit: piece / mm ² ]), density of protrusions having a height of 30 nm or more (projection density D (30) [unit: piece / mm ² ]), density of protrusions having a height of 40 nm or more (projection density D (40) [Unit: unit/mm ² ]), density of protrusions having a height of 50 nm or more (projection density D (50) [unit: unit / mm ² ]). The density of the protrusions is obtained by binarizing the AFM image described above by setting the brightness corresponding to the height of each protrusion as a threshold value, and counting the number of blocks of brightness and pressing each 1mm ² for conversion.

The seven types of film 10 were plotted in a graph in which the projection axis density D (10) on the horizontal axis and the ratio S of the attachment area on the vertical axis were plotted, and the graph shown in Fig. 16 was obtained. The projection axis density D (30) was taken from the horizontal axis and the same plot was performed, and the graph shown in Fig. 17 was obtained. The projection axis density D (40) was taken from the horizontal axis and the same plot was performed, and the graph shown in Fig. 18 was obtained. Further, the horizontal axis took the projection density D (50) and performed the same plotting, and as a result, the graph shown in Fig. 19 was obtained.

As can be seen from the graph of Fig. 16, the protrusion density D(10) is a factor which has little influence on the ratio S of the attached area. On the other hand, as shown in the graphs of Figs. 17, 18, and 19, the projection density D (30), the projection density D (40), and the projection density D (50) are both the ratio S to the attached area. A factor with strong correlation. It is understood that the larger the protrusion density D (30), the protrusion density D (40), and the protrusion density D (50), the smaller the ratio S of the attachment area.

In addition to the 16th to 19th drawings, the seven types of film 10 are also drawn in a graph in which the projection density D (20) on the horizontal axis and the ratio S in the vertical axis are attached (not shown). The contribution rate (multiple decision coefficient) R ^{2 is} obtained for the five graphs. As a result of obtaining the contribution rate R ² , the horizontal axis represents the projection height H [unit: nm] which is the threshold value in the above five graphs, and the vertical axis takes the contribution rate R ² as a graph, and the result is obtained. Figure 20 is a graph. It can be seen from the graph that the protrusion having a height of 30 nm or more contributes to the reduction of the ratio S of the attachment area, wherein the protrusion having a height of 40 nm or more is more conducive to reducing the ratio S of the attachment area, wherein the height is 50 nm. The above protrusions further contribute to reducing the ratio S of the attachment area.

[Example 4]

In the fourth embodiment, ten types of the film 10 produced by the same methods as those of the above-described first and second embodiments were used, and it was confirmed that the particles of the attached protrusions were effectively reduced. 10 films The ratio S of the attachment area in the method of the above-mentioned attachment evaluation is randomly selected from 0% to 50%.

The SEM (Scanning Electron Microscope) was observed in a direction substantially perpendicular to the film surface 10a of the ten types of the film 10, and the secondary particle diameter r2 of the fine particles existing on the film surface 10a of each film 10 was examined. distributed. The ten kinds of the film 10 were plotted on the horizontal axis with a ratio N of the content ratio N (0.7) [unit: %] of the fine particles 14 and the ratio S of the vertical axis to the attached area, and the result was obtained in Fig. 21. The graph shown. As can be seen from Fig. 21, when the content ratio N (0.7) is 30% or more, the ratio S of the attachment area is less than 20%, and when the content ratio N (0.7) is 50% or more, the ratio of the attachment area is less than 10%. . From this, it was confirmed that in order to reduce the adhesion between the films to be overlapped, it is important to set the content ratio N (0.7) in the dope forming the film to be high.

22‧‧‧ Film roll

10, 20‧‧‧ film

23‧‧‧Volume core

23a‧‧‧Volume Holding Department

Claims (10)

A film roll comprising: a winding core; and an elongated polymer film wound around the winding core in a roll shape, and a contact surface pressure applied to a film surface of the polymer film is 0.05 MPa or more and 0.10 MPa or less The static friction coefficient of the part in the range is 1.2 or less. The film roll according to the first aspect of the invention, wherein the film having a height of 30 nm or more is formed in a range of 10 ⁴ or more and 10 ⁶ or less per 1 mm ^{2 of the} film surface. The film roll of claim 2, wherein the polymer film is a cellulose vapor film. The film roll according to claim 3, wherein the protrusion after the saponification treatment of the film surface is formed in a range of 10 ⁴ or more and 10 ⁶ or less per 1 mm ^{2 of the} film surface. The film roll according to claim 3, wherein the polymer film is used by a polarizing film on the film surface after the saponification treatment. The film roll according to any one of claims 2 to 4, wherein the fine particles are cerium oxide. The film roll of claim 5, wherein the fine particles are cerium oxide. A method of manufacturing a film roll, comprising the steps of: (A) producing a concentrated liquid composition comprising a polymer, a solvent for dissolving the polymer, and fine particles dispersed in a state of secondary particles, wherein the fine particles have a secondary particle diameter of 0.7 μm or more. a ratio of at least 30% to the total number of the particles; (B) forming a cast film on the support by continuously discharging the dope composition from the casting die to the continuously running support; (C) The cast film is peeled off from the support and dried to obtain a polymer film; and (D) the polymer film is wound up on a core. The method for producing a film roll according to claim 8, wherein the step A includes the step of: (E) mixing the polymer and the solvent, and heating and stirring at least one of Dissolving the polymer in the solvent to prepare a raw material concentrate; (F) mixing and stirring the polymer and solvent having the same composition as the polymer and the solvent, and the fine particles to obtain a liquid mixture; (G) in the foregoing In the mixture, the fine particles are dispersed as secondary particles to obtain a fine particle dispersion, and in the fine particle dispersion, a ratio of the fine particles having a secondary particle diameter of 0.7 μm or more to the total number of the fine particles is at least 30%; And (H) mixing the raw material dope and the fine particle dispersion to obtain the dope composition. A method for producing a film sheet comprising the steps of: (A) producing a dope composition comprising a polymer, a solvent for dissolving the polymer, and fine particles dispersed in a state of secondary particles, in the dope composition The content ratio of the fine particles having a secondary particle diameter of 0.7 μm or more to the total number of the fine particles is at least 30%; (B) forming a cast film on the support by continuously discharging the dope composition from the casting die to the continuously running support; (C) peeling the cast film from the support and drying it To obtain a polymer film; (D) winding the polymer film onto the core; and (I) drawing the polymer film from the film roll and cutting the film sheet from the drawn polymer film.