JP5623453B2 - Polymer film roll, optical film, and polymer film roll manufacturing method - Google Patents

Description

The present invention relates to a polymer film roll, an optical film, and a method for producing a polymer film roll.

  Polymer films are widely used as optical films and the like because of their features such as excellent light transmission and flexibility, and being capable of reducing the weight of thin films. Among them, cellulose ester films using cellulose acylate and the like are optical films such as a protective film for a polarizing plate and a retardation film, which are constituent members of liquid crystal display devices whose market is expanding in recent years, including photographic photosensitive films. Used in film.

  The polymer film is continuously manufactured in a strip shape by a melt film forming method, a solution film forming method, or the like. This polymer film is wound into a roll shape around, for example, a cylindrical winding core, stored as a film roll, and transported.

  As shown in FIGS. 10 and 11, when the polymer film 3 is wound around the core 2, a double-sided adhesive tape (hereinafter simply referred to as a double-sided tape) is used so that the tip 3 a of the film 3 does not fall off from the core 2. 4) and a single-sided adhesive tape (hereinafter simply referred to as single-sided tape) 5 to fix the film tip 3a to the winding core 2.

  As described above, when the polymer film 3 is wound around the winding core 2 in a roll form, a step 6 called a so-called cut image appears on the second and subsequent web surfaces at a position overlapping the tip (cut) 3 a of the film 3. The step 6 may occur from the winding position to the 100th winding or more, depending on the web type of the film 3 and the winding condition. The cut-out image formed by the step 6 becomes a failure for a web that requires smooth flatness, for example, an optical film, and causes a large loss.

  For this reason, various methods for reducing the cut-off image have been proposed. For example, in Patent Document 1, the thickness of the knurling that is processed to be thickened at both side edges in the width direction of the web is gradually reduced from the winding core side to the outer peripheral side and wound. Moreover, in patent document 2, the convex step part of the height of 1-10 times the film thickness wound is formed in the both ends outer peripheral part of a cylindrical winding core. Moreover, in patent document 3, it replaces with the said convex step part, and a bonding tape is affixed on the both ends outer peripheral part of a cylindrical winding core. In this way, a convex step or bonding tape is provided on the outer periphery of both ends of the winding core, or a knurling is provided on both side edges of the web so that the surface pressure applied in the radial direction to the web in the central portion is low. By doing so, the occurrence of cut ends is suppressed. In Patent Document 4, an elastic body that is thicker than the thickness of the sheet is provided on the outer peripheral surface of the winding core to suppress the occurrence of step marks generated at the step at the end of the sheet winding.

JP-A-8-244035 Japanese Patent Laid-Open No. 9-58935 JP 2001-63876 A JP 2011-207592 direction

  However, as in Patent Document 1, it is difficult to gradually reduce the protruding amount of the knurling, and there is a problem that the knurling device becomes complicated. In addition, in the case where a step portion is provided on the outer peripheral surfaces of both ends as in Patent Document 2, it is necessary to align both side edges of the web with the step portion. In Patent Document 3, in addition to the necessity to affix the joining tape to both ends of the winding core, it is necessary to align both side edges of the web, and there is a problem that skill is required for winding. In Patent Document 4, winding wrinkles and dents (so-called “bevels”) due to steps are generated in a thin film having a film thickness of 60 μm or less.

This invention solves the above subjects, and it aims at providing the polymer film roll, the optical film, and the polymer film roll manufacturing method which were made to suppress generation | occurrence | production of a cut-off image.

In order to achieve the above object, the polymer film roll of the present invention has a belt-shaped polymer film having a thickness of 60 μm or less fixed to the outer peripheral surface of the core with a double-sided tape, and the polymer film is wound around the core. a composed polymeric film roll, along the distal end of the polymer film, winding mounted on the outer circumferential surface of the core, thinner than the thickness of the polymer film has a resilient outer peripheral surface and core of the tip portion of the polymer film It is characterized by comprising a cushioning material arranged stepwise between the surface .

Double-sided tape thickness is smaller than the thickness of the polymer film, in a state where the tip from exposing the double-sided tape of the polymer film, the polymer film is secured to the double-sided tape, the buffer material is disposed on the exposed sided tape section that it is preferable. The cushioning material has a first cushioning material having a first end near the polymer film tip, and a second cushioning material having a second end far from the polymer film tip, and the second cushioning material is more than the first cushioning material. It is preferable that the thickness of the material is thin and the second cushioning material is disposed in a stepped manner lower than the first cushioning material between the surface of the tip of the polymer film and the outer peripheral surface of the winding core. The buffer material preferably has a length in the circumferential direction of the core of 2% or less of the circumferential length of the core. The gap in the circumferential direction of the core between the polymer film tip and the cushioning material is preferably 0.1 mm or more and 20 mm or less.

  The optical film of the present invention is formed by cutting the web into a sheet using the above-described web roll.

Polymeric film roll production method of the present invention has a thickness in the polymeric film roll manufacturing method and wound on the core winding the following polymer film 60μm to produce a polymer film roll, for adhering to the core winding the leading end of the polymer film Affixing a double-sided tape and a cushioning material that is thinner and more elastic than the thickness of the polymer film and that is placed in a stepped manner between the surface of the tip of the polymer film and the outer peripheral surface of the core a step, a core of double-sided tape and cushioning material is adhered to set the polymeric film winding position, fixed to the core winding a polymer film tip by means of a double-sided tape tip close to the cushioning material of the polymer film a polymer film a distal end fixing step, the polymer of winding the polymer film winding core by rotating the core Characterized in that it comprises a Irumu rolling process.

According to the present invention, the thickness along the distal end of the following strip of polymer film 60 [mu] m, attached to the outer peripheral surface of a winding core thinner than the thickness of the polymer film has a resilient surface of the tip portion of the polymer film And a cushioning material arranged stepwise between the outer peripheral surface of the winding core, when the next polymer film is wound around the tip of the polymer film, the cushioning material arranged stepwise is wound next. It is possible to suppress deformation of the polymer film. As a result, the length at which the next polymer film hits the tip of the polymer film and becomes a cut edge can be shortened, and the polymer film can be effectively utilized by that much.

It is the schematic which shows the film roll manufacturing equipment of this invention. It is a top view which shows the attachment state of the film front-end | tip to a winding core. It is a perspective view which shows the cross section of the III-III line in FIG. It is sectional drawing equivalent to the III-III line | wire in FIG. 2 of the state by which the film was wound 3 times at the film front-end | tip part. It is sectional drawing equivalent to the III-III line in FIG. 2 of 2nd Embodiment of this invention. It is sectional drawing equivalent to the III-III line in FIG. 2 of 3rd Embodiment of this invention. It is sectional drawing equivalent to the III-III line | wire in FIG. 2 of the film winding state of the embodiment. It is sectional drawing equivalent to the III-III line in FIG. 2 of 4th Embodiment of this invention. It is a top view which shows the attachment state of the film front end to the winding core in another embodiment which changed the inclination angle of the film front end. It is sectional drawing which shows the attachment state of the conventional method to the winding core of the film tip by a double-sided tape. It is sectional drawing which shows the attachment state of the conventional method to the winding core of the film tip by a single-sided tape.

  As shown in FIG. 1, a film roll (web roll) production facility 10 of the present invention includes a film production line 11, a knurling device 12, and a winding device 13. Although not shown, the film production line 11 has a casting apparatus, a tenter, and a drying apparatus in order, and for example, a belt-shaped polymer film 15, for example, a TAC (triacetyl cellulose) film is manufactured by a solution casting method.

  The knurling device 12 is disposed between the film production line 11 and the winding device 13. The knurling device 12 includes a support roller 16, a knurling roller 17, and shift units 18 and 19. When knurling is applied, the support rollers 16 and the knurling roller 17 are moved to the nip position by the shift portions 18 and 19, and knurling (not shown) is formed on both side edges (ear portions) of the polymer film 15 by embossing.

  The winding device 13 has a turret arm 21 and winds the polymer film 15 around a winding core 23 set on a winding shaft 22. The turret arm 21 is intermittently rotated, for example, 180 degrees by an arm driving unit (not shown), and the winding core 23 is selectively switched between the winding position PS1 and the winding core replacement position PS2. A guide arm 25 is provided at an intermediate position in the rotational direction of the turret arm 21, and a guide roller 26 is attached to the distal end portion of the guide arm 25. The guide roller 26 supports the polymer film 15 so that the polymer film 15 does not come into contact with the turret arm 21 or the arm mounting shaft 27 when the turret arm 21 is rotating.

  The winding shaft 22 is provided at the tip of the turret arm 21. A winding core 23 is set on the winding shaft 22. At the winding position PS 1, the polymer film 15 sent from the guide roller 28 is wound around the winding core 23. Further, at the winding core replacement position PS2, the film roll 29 that has been wound up with a certain length of the polymer film 15 is removed from the winding shaft 22 together with the winding core 23. An empty core 23 is set, and the core 23 is exchanged.

  When the film roll 29 is almost fully wound at the winding position PS1, the turret arm 21 rotates 180 degrees, and the film roll 29 that is almost fully wound is positioned at the winding core replacement position PS2. An empty winding core 23 is positioned at the winding position PS1. When the film roll 29 reaches a predetermined length, the film cutting device 14 operates to cut the polymer film 15. As the film cutting device 14, for example, a web rewinding device described in JP-A-2005-89177, JP-A-2008-230723, or the like is used. The rear end portion of the cut preceding polymer film 15 is wound around the film roll 29 at the winding core replacement position PS2. Further, the leading end of the cut polymer film 15 after being cut is wound around the empty winding core 23 at the winding position PS1.

  Hereinafter, in the same manner, the polymer film 15 is wound around the winding core 23, whereby the polymer film 15 continuously fed becomes a product as a film roll 29. In the next step, the film roll 29 obtained in this way is unwound and cut into a required size into a sheet shape. For example, the film roll 29 is used as a polarizing plate protective film or a retardation film. Further, the polymer film 15 is provided with an optically anisotropic layer, an antireflection layer, an antiglare function layer, or the like, if necessary, and used as a high function film.

  As shown in FIG. 2, a double-sided tape 31 and a buffer material 32 are attached to the empty winding core 23. The double-sided tape 31 is for fixing the tip of the polymer film 15 to the winding core 23.

  As shown in FIG. 3, the double-sided tape 31 has, for example, a first adhesive layer 31b on the winding core side on one side (back side) of a belt-like support 31a made of PET (polyethylene terephthalate), and the other side (front side). A second adhesive layer 31c on the film side is formed. The thickness t02 of the double-sided tape 31 is not less than 10 μm and not more than 60 μm, preferably not less than 10 μm and not more than 30 μm, more preferably not less than 10 μm and not more than 15 μm. As this double-sided tape 31, for example, Nitto Denko (model: 5601, 5603, 5605, 5606) is used. 3 and the subsequent cross-sectional views, it is difficult to distinguish each member such as the polymer film 15, the double-sided tape 31, and the cushioning material 32 when displayed in actual dimensions. Therefore, in each figure, the dimension in the thickness direction is exaggerated. It is displayed.

  The width W02 of the double-sided tape 31 is 25 mm or more and 150 mm or less, preferably 40 mm or more and 90 mm or less, more preferably 40 mm or more and 60 mm or less. If it is less than 25 mm, it becomes affixed poorly, and if it exceeds 150 mm, wrinkles tend to occur in the tape, which is not preferable.

  The adhesive layers 31b and 31c of the double-sided tape 31 are formed on the entire surface of the support 31a. These adhesive layers 31b and 31c have the same composition and thickness, but may have different compositions and different thicknesses. Although not shown, a release tape is attached to the surface on which the second adhesive layer 31c is formed. The release tape is peeled off after the double-sided tape 31 is attached to the winding core 23 by the first adhesive layer 31b and before the polymer film 15 is wound up.

  The buffer material 32 is made of, for example, polyester, nonwoven fabric, or the like, and is formed thinner than the thickness of the polymer film 15 to be wound. And what has elasticity rather than the double-sided tape 31 is used. The cushioning material 32 may not have an adhesive layer itself, and in this case, the cushioning material 32 is attached to the winding core 23 via the double-sided tape 31.

  As shown in FIG. 2, the width W03 of the buffer material 32 is 5 mm or more and 30 mm or less, preferably 8 mm or more and 18 mm or less, and more preferably 8 mm or more and 12 mm or less. If the thickness is less than 5 mm, poor bonding to the winding core occurs, and if it exceeds 30 mm, the cut-out image cannot be improved, and both are not preferable. In addition, when determining the width W03 of the buffer material 32 based on the core circumference, it is preferably 2% or less of the core circumference.

  As shown in FIG. 3, the thickness t03 of the cushioning material 32 varies depending on the number of cushioning materials used. For example, as shown in FIGS. 2 to 5, when there is one cushioning material 32, 33, the thickness of the polymer film 15 is 10% or more and 90% or less, preferably 25% or more and 75% or less, more preferably 35 % To 65%. When the thickness of the cushioning material 32 is less than 10% or more than 90% of the thickness of the polymer film 15, the effect of improving the cut-out appearance is reduced. As shown in FIGS. 6 to 8, when there are a plurality of cushioning materials 41 to 44, the thickness may be gradually reduced from the cushioning materials 41 to 44 close to the film leading end 15a. In this case, it is desirable to suppress the difference in thickness between the buffer materials 41 to 44 to 5% or more and 30% or less of the thickness of the polymer film 15.

  In the case of the cushioning material 33 having the adhesive layer 33b on at least one surface of the cushioning material main body 33a as in the second embodiment shown in FIG. 5, the double-sided tape 31 is not used and the winding core 23 is directly used. Is pasted. In the following embodiments, the same constituent members are denoted by the same reference numerals, and redundant description is omitted.

  6 and 7 show a third embodiment of the present invention, in which two types of cushioning materials 41 and 42 having different thicknesses are arranged side by side in the winding direction of the polymer film 15. The first buffer material 41 near the tip 15a of the polymer film 15 and the second buffer material 42 far from the tip 15a both have thicknesses t12 and t22 that are equal to or less than the thickness t01 of the polymer film 15 and t12> t22. The widths W12 and W22 of the first buffer material 41 and the second buffer material 42 are 0.5% or more and 6.0% or less of the circumferential length of the winding core.

  In the third embodiment, the thicknesses t21 and t22 of the first cushioning material 41 and the second cushioning material 42 are changed in two steps, so that the bending deformation of the step mark is made in two steps as compared with the first embodiment. Compared to the one of the cushioning material 32 of the first embodiment, the length of occurrence of the step trace becomes shorter.

  In the fourth embodiment, instead of the third embodiment shown in FIGS. 6 and 7, as shown in FIG. 8, the shock absorber 43 having adhesive layers 43 b and 44 b on at least one surface of the shock absorber main bodies 43 a and 44 a. 44 are used. In this case, the buffer materials 43 and 44 are directly attached to the winding core 23 without using the double-sided tape 31.

  The elastic modulus (Young's modulus) of each buffer material 41-44 is changed instead of changing the thickness t12, t22 of each buffer material 41-44, or the elastic modulus (Young's modulus) together with the thickness of each buffer material 41-44. ) May be changed so that the amount of compressive deformation of the second cushioning materials 42 and 44 moving away from the film leading end 15 a is larger than the amount of compressive deformation of the first cushioning materials 41 and 43. In this case, the occurrence of a step due to the influence of the film front end is suppressed by the two cushioning materials, and the cut-out image can be further suppressed.

  It is preferable to change the relationship between the elastic modulus and the thickness of the buffer materials 32, 33, and 41 to 44 according to the elastic modulus of the polymer film 15 to be wound. For example, when the elastic modulus of the polymer film 15 is Ep and the elastic modulus of the buffer material is Eb, when Ep ≦ Eb, when the thickness of the polymer film is tp and the thickness of the buffer material is tb, (tp / 2) <tb <tp. When Ep> Eb, tp <tb <2 · tp.

  As shown in FIG. 2 and FIG. 3, the gap G01 from the film tip 15a to the cushioning material 32 is not less than 0.1 mm and not more than 20 mm, preferably not less than 0.1 mm and not more than 10 mm, more preferably not less than 0.1 mm and not more than 8 mm. It is as follows. If it is less than 0.1 mm, the film 15 tends to overlap the buffer material 32, and if it exceeds 20 mm, a step is generated between the film tip 15 a and the buffer material 32, which causes a cut-off and is not preferable.

  As shown in FIG. 4, when the polymer film 15 is wound on the winding core 23 and the next film 15 overlaps the film tip 15a, the influence of the step of the polymer film 15 wound with the buffer material 32 is mitigated. To do. Thereby, extreme bending does not occur in the polymer film 15. Thereafter, the next film is wound up in the same manner, but in any case, extreme bending deformation does not occur due to the influence of the cushioning material 32, and the occurrence of cut-out is suppressed.

  Adhesion of the double-sided tape 31 and adhesion of the film front end portion with the double-sided tape 31 may be performed manually, or the film cutting device 14 (see FIG. 1) may be used. In the case of manual operation, a film reservoir (not shown) is provided immediately before the winding device 13. The film reservoir temporarily stores the film 15 for the time required for cutting the polymer film 15 and fixing it to the winding core 23, and during this storage, the film 15 is cut and wound around the winding core 23. Do. Moreover, when performing automatically, the film cutting device 14 is used and the polymer film 15 is cut and fixed to the winding core 23. In this case, the position of the double-sided tape 31 on the winding core 23 is automatically detected, the polymer film 15 is cut based on the detection timing, and the cut film tip 15a is separated from the cushioning material 32 with a predetermined gap G01. The film leading end is bonded to the second adhesive layer 31c.

  In addition, although the double-sided tape 31 and the buffer materials 32, 33, and 41 to 44 were previously attached to the winding core 23, the double-sided tape 31 and the buffer materials 32, 33, and 41 are attached to the film cutting drum on the film cutting device 14 side. To 44, and when the film 15 is cut by the film cutting drum, the double-sided tape 31 and the cushioning materials 32, 33 and 41 to 44 are attached to the winding core 23 together with the film 15, and the film 15 is wound up. Also good.

  As shown in FIGS. 6 to 8, instead of changing the elastic modulus and thickness of the two buffer materials 41 to 44, the first edge on the side closer to the film tip 15 a is omitted with respect to one buffer material. The thickness may be gradually decreased from the second end edge on the side far from the distance. Also in this case, an extreme bending deformation does not occur in the film wound next by the cushioning material, and the occurrence of the cut-out image can be suppressed.

  As shown in FIG. 9, the inclination angle θ1 of the film leading end 15a with respect to the film width direction reference line BL1 is preferably in the range of −30 ° <θ1 <30 °, more preferably in the range of −20 ° <θ1 <20 °. More preferably, the range is −10 ° <θ1 <10 °. The closer the tilt angle θ1 is to 0 °, the smaller the stress due to the influence of the film surface pressure that overlaps with the film leading end 15a thereafter, thereby suppressing the cut-off. As described above, when the tip 15a of the polymer film 15 is cut at a predetermined inclination angle θ1, the double-sided tape 31 and the cushioning materials 32, 33, 41 to 44 are also inclined in accordance with the inclination angle θ1 of the film tip 15a. Affixed to the core 23 at an angle θ1.

  In addition, although the width | variety of the polymer film 15 is not specifically limited, It is preferable that it is 600 mm or more, and it is more preferable that it is 1400 mm or more and 2500 mm or less. Moreover, it is also effective when the width of the polymer film 15 is larger than 2500 mm. The thickness of the polymer film 15 is preferably 30 μm or more and 200 μm or less, more preferably 40 μm or more and 150 μm or less, and further preferably 40 μm or more and 100 μm or less. The length of the polymer film 15 is preferably 2000 m or more, and more preferably 4000 m or more and 8000 m or less. Further, the winding radius of the film roll 29 is preferably 450 mm or more, and more preferably 650 mm or more and 920 mm or less.

  The length L2 of the double-sided tape 31 in the cylinder center direction of the winding core 23 is not particularly limited, but L2 = (W1-0) mm to (W1-10) mm based on the width W1 of the polymer film 15. Is preferred.

  The polymer used as the raw material for the polymer film 15 is not particularly limited. In the solution casting method, for example, cellulose acylate or cyclic polyolefin is used. In the melt film-forming method, for example, cellulose acylate, a lactone ring-containing polymer, a cyclic polyolefin, polycarbonate, or the like is used. The details of cellulose acylate are described in paragraphs [0140] to [0195] of JP-A-2005-104148. These descriptions can also be applied to the present invention. The same applies to additives such as solvents and plasticizers, deterioration inhibitors, ultraviolet absorbers (UV agents), optical anisotropy control agents, retardation control agents, dyes, matting agents, release agents, and release accelerators. JP-A-2005-104148 describes in detail in paragraphs [0196] to [0516].

  In each of the above-described embodiments, the method for producing the film roll 29 in which the polymer film 15 is wound into a roll form has been described. Can be implemented. In each of the above embodiments, the polymer film 15 is bonded to the winding core 23 using the double-sided tape 31, but the film may be bonded to the winding core with an adhesive instead of the double-sided tape 31. Similarly, the buffer material may be bonded to the winding core with an adhesive.

  Next, in order to confirm the presence or absence of the effect of the present invention, the following experiment was performed. In the film roll manufacturing facility 10 shown in FIG. 1, a film roll 29 made of TAC having a length of 5000 m, a width of 1500 mm, a thickness of 60 μm, and 40 μm was manufactured.

Example 1
Example 1 is of the first embodiment shown in FIG. 5, the thickness of the polymer film 15 is 60 μm, and the compression change rate (hereinafter simply referred to as the compression change rate) under a pressure of 0.5 Mpa is 1%. The thickness of the buffer material 33 is 55 μm, the compression change rate under the pressure of 0.5 Mpa (hereinafter simply referred to as compression change rate) is 48%, and the gap G01 from the film tip 15a to the buffer material 33 is 0.1 mm, The inclination angle θ1 shown in FIG. In the measurement of the elastic modulus in the thickness direction of the film, a compression tester was used. In the compression test, a laminate of 10 to 100 films was placed on a scale, and the submerged length Lp1 when a pressure of 0.5 Mpa was applied from above the film laminate was measured. From this result, the compression change rate (%) per film was calculated. The compression change rate is a value of (Lp1 / Lp0) × 100 (%) when the length before pressurization is Lp0 and the subsidence length after pressurization is Lp1.

(Example 2)
In Example 2, the same conditions as in Example 1 were adopted except that the gap G01 was set to 5 mm.

Example 3
In Example 3, the same conditions as in Example 2 were adopted except that the compression change rate of the buffer material was set to 30%.

Example 4
In Example 4, the same conditions as in Example 2 were adopted except that the compression change rate of the buffer material was set to 60%.

(Example 5)
In Example 5, the same conditions as in Example 1 were used except that the gap G01 was 10 mm.

(Example 6)
Example 6 The conditions were the same as in Example 1 except that the gap G01 was 20 mm.

(Example 7)
In Example 7, the same conditions as in Example 1 were used except that the gap G01 was set to 25 mm.

(Example 8)
In Example 8, the same conditions as in Example 2 were used except that the thickness of the buffer material was set to 30 μm.

Example 9
In Example 9, the same conditions as in Example 8 were adopted except that the thickness of the film was 40 μm.

(Example 10)
Example 10 is the same as the fourth embodiment shown in FIG. 8, the film thickness is 60 μm, the compression change rate is 1%, the thickness of the first buffer material 43 is 55 μm, the compression change rate is 25%, The thickness of the second buffer material 44 is 30 μm, the compression change rate is 25%, and the gap G01 from the film tip 15a to the first buffer material 43 is 5 mm.

(Example 11)
Example 11 is the same as the fourth embodiment shown in FIG. 8 except that the thickness of the film is 40 μm, the thickness of the first buffer material 43 is 30 μm, and the thickness of the second buffer material 44 is 10 μm. And the same conditions.

(Comparative Example 1)
Comparative Example 1 was the same as Example 1 except that the double-sided tape 4 in the conventional system shown in FIG. 10 was used, no buffer material was used, and the film tip was attached to the winding core.

(Comparative Example 2)
In Comparative Example 2, the same conditions as in Example 2 were used except that the thickness of the buffer material 33 was 110 μm and the compression change rate was 25%.

(Comparative Example 3)
In Comparative Example 3, the same conditions as in Example 1 were used except that the thickness of the film was 40 μm, the thickness of the buffer material 33 was 75 μm, and the gap G01 was 10 mm.

(Comparative Example 4)
In Comparative Example 4, the same conditions as in Example 11 were used except that the thickness of the first buffer material 43 was 75 μm and the thickness of the second buffer material 44 was 30 μm.

  Other control conditions during winding are as follows. A film roll 29 was produced on the film production line 11 shown in FIG. 1 with a tension applied to the film 15 of 100 N / film width, a film running speed of 60 m / min, and a diameter of the winding core 23 of 169 mm.

  The film roll 29 wound up by the above method is stored for 30 days in an environment of 25 ° C. and 65% RH. Next, the film roll 29 after 30 days is set in a winder (not shown) and rewinded. By the rewinding by this rewinding, it is possible to observe the film leading end portion wound up near the core of the film roll 29. Next, an evaluation test for determining the length (cutting length) L3 until the cutout disappeared was performed on the film front end. In the evaluation test, the film tip is placed on a table covered with a black cloth. Next, the film surface is irradiated with light from a fluorescent lamp from above. It is evaluated with the naked eye whether there is a cut-out image with the reflected light. Then, the length until the cut-out image near the winding core disappeared (the cut-out image length) was obtained.

  When ten film rolls 29 were manufactured and inspected, the evaluations shown in Table 1 were obtained. In each of Examples 1 to 11, as apparent from Table 1 below, the length L3 from the winding core portion where the cut-out image is NG is reduced compared to that of the conventional comparative example 1, and the cut-off failure is improved. It can be seen that Note that the NG level of the cut-out image was based on a limit sample (a sample showing the quality limit to be a good product or a defective product).

  The evaluation (◎) in Table 1 means that the film length L3 that becomes the cut edge NG from the winding core is less than 10 m, and the cut edge is good. (◯) means that the length L3 is 10 m or more and less than 30 m, and the cut-out image is slightly weak but is OK. (Δ) also means that the length L3 is 30 m or more and less than 50 m, and a cut-out image is generated, but there is no practical problem. (X) means that the length L3 is 50 m or more and the product loss is large and NG.

  As can be seen from the evaluation of Examples 1, 2, and 5 to 7, when the gap G01 is 20 mm or less, a cut-out image reduction effect is obtained, but when it exceeds 20 mm, the cut-out image reduction effect decreases. . In addition, it can be seen that Examples 10 and 11 using two cushioning materials have a higher cut-off effect than Example 1 using one cushioning material. Further, as in Comparative Examples 2 to 4, it can be seen that when the cushioning material is thicker than the film, the effect of reducing the cut-out image is low.

  4, 6, and 7, even if the cushioning materials 32, 41, and 42 are fixed to the winding core 23 by the double-sided tape 31, the cushioning materials 33, 43, and 44 shown in FIGS. The same cut-out reduction effect as that fixed to the core 23 on the adhesive layers 33b, 43b, 44b is obtained. Further, as shown in FIG. 9, the occurrence of cut-off can be suppressed by applying the present invention to a film in which the inclination angle θ1 of the film front end with respect to the width direction reference line BL1 is changed. As for the inclination angle θ1, the smaller the angle, the shorter the cut-out length, which is preferable.

DESCRIPTION OF SYMBOLS 10 Film roll production equipment 11 Film production line 12 Knurling device 13 Winding device 15 Polymer film 23 Core 31 Double-sided tape 32, 33, 41-44 Buffer material

Claims (7)

The distal portion of the core outer circumferential surface to a thickness of less strip 60μm polymer film was fixed by double-sided tape, a said polymer film roll made by winding a polymeric film on the spool having,
Along the tip of the polymer film, attached to the outer peripheral surface of the winding core, the thinner than the thickness of the polymer film has elasticity, the outer peripheral surface of the surface and the winding core of the distal portion of the polymer film A polymer film roll comprising a cushioning material disposed in a stepped manner therebetween . The thickness of the double-sided tape is smaller than the thickness of the polymer film ,
The polymer film is fixed to the double-sided tape with the double-sided tape exposed from the tip of the polymer film, and the cushioning material is disposed on the exposed surface of the double-sided tape. Item 11. A polymer film roll according to Item 1 . The cushioning material has a first cushioning material having a first end portion close to the polymer film tip, and a second cushioning material having a second end portion far from the polymer film tip, than the first cushioning material. The second cushioning material is thin, and the second cushioning material is arranged in a stepped manner lower than the first cushioning material between the surface of the tip of the polymer film and the outer peripheral surface of the winding core. claim 1 or 2, wherein the polymer film roll, wherein the that. The polymer film roll according to any one of claims 1 to 3 , wherein the cushioning material has a length in the circumferential direction of the core that is 2% or less of the circumferential length of the core. The polymer film roll according to any one of claims 1 to 4 , wherein a gap between the tip of the polymer film and the cushioning material in the circumferential direction of the core is 0.1 mm or more and 20 mm or less. An optical film comprising the polymer film roll according to any one of claims 1 to 5 , wherein the polymer film is cut into a sheet shape. In the polymer film roll manufacturing method thickness wound in the core winding the following strip of polymer film 60μm to produce a polymer film roll,
And double-sided tape to adhere the leading edge of the polymer film to the winding core, is resilient thinner than the thickness of the polymer film, between the outer peripheral surface of the surface and the winding core of the distal portion of the polymer film A step of attaching a cushioning material arranged in a staircase shape to the winding core;
Fixing the said winding core double-sided tape and cushioning material is adhered to set the polymeric film winding position, the core winding the polymer film tip by tip close to the buffer member the double-sided tape of the polymer film A polymer film tip fixing step,
Polymeric film roll manufacturing method characterized by comprising a polymer film winding step of winding the polymer film to be allowed the winding-out by the core rotating the winding core.

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