JP2013199354A - Web roll, optical film, and method for producing web roll - Google Patents

Abstract

PROBLEM TO BE SOLVED: To suppress cut edge copying in a film roll.SOLUTION: A belt-like bonding tape 31 is affixed to an outer peripheral surface of a winding core 23. The bonding tape 31 is constituted of a belt-like supporting body 31a, a winding core side adhesive layer 31b formed in one surface of the supporting body 31a, and a film side adhesive layer 31c formed in the other surface of the supporting body 31a. With a part of the film side adhesive layer 31c exposed from a film leading end part 15a, a film leading end part 15b is bonded to a remaining part of the film side adhesive layer 31c, and the film leading end part 15b is fixed to the winding core 23. The supporting body 31a and the respective adhesive layers 31b, 31b function as cushioning materials. The next film 15 overlapping the end edge at the film leading end part 15a is moderately curved, and the generation of cut edge copying is suppressed.

Description

  The present invention relates to a web roll, an optical film, and a web roll manufacturing method.

  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 FIG. 8, when the polymer film 3 is wound around the core 2, the film tip 3 a is attached to the core 2 by the bonding tape 4 or the like so that the tip 3 a of the film 3 does not fall off from the core 2. Secure to. As for the joining tape 4, the adhesion layers 4b and 4c are formed in both surfaces of the support body 4a. And the outer peripheral surface 2a of the winding core 2 and the joining tape 4 are joined via the adhesion layer 4b. Moreover, the film front-end | tip part is fixed to the winding core 2 through the adhesion layer 4c.

  In this way, when the polymer film 3 is wound around the winding core 2 in a roll form, a step 5 called a so-called cut image appears on the second and subsequent web surfaces at a position overlapping the tip (cut edge) 3a of the film 3. The step 5 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 of the step 5 becomes a failure for a web that requires smooth flatness, such as 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-outs is suppressed.

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

  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.

  This invention solves the above subjects, and it aims at providing the web roll and manufacturing method which suppressed generation | occurrence | production of a cut-off image.

  In order to achieve the above object, the web roll of the present invention is a web roll formed by fixing the leading end of a belt-like web to the outer peripheral surface of a winding core with a joining member, and winding the web around the winding core. The member is formed on the support, the core-side adhesive layer formed on one surface of the support, and the other surface of the support. The web tip is covered and the web tip is fixed to the core. The web-side adhesive layer is composed of the web-side adhesive layer, and the web-side adhesive layer is bonded to the web-side adhesive layer with the blank portion of the web-side adhesive layer exposed from the web tip, and the web tip is fixed to the winding core. It is characterized by that.

  In addition, it is preferable that the buffer material is arrange | positioned in the blank part. The cushioning material is preferably formed of an elastic member that is formed thicker than the thickness of the web and deforms below the thickness of the web by winding the web. The leading end of the web is cut so that the inclination angle θ1 with respect to the reference line in the web width direction is within a range of −30 ° <θ1 <30 °, and the joining member is attached to the outer peripheral surface of the winding core in parallel with the leading end of the web. It is preferable to be attached.

  When the thickness of the joining member is t1 and the web thickness is t0, (0.5 × t0) ≦ t1 ≦ (1.5 × t0), and when the thickness of each adhesive layer is t2, (0 .3 × t1) ≦ t2 ≦ (0.6 × t1).

  Moreover, the optical sheet of the present invention is characterized in that the web is cut into a sheet shape using any one of the above-described web rolls, and the web is an optical film.

  The web roll manufacturing method of the present invention comprises a joining member having a belt-like support, a first adhesive layer formed on one surface of the support, and a second adhesive layer formed on the other surface of the support. A bonding member affixing step for fixing to a winding core via one adhesive layer; a winding core with the bonding member affixed to the web winding position; and a portion of the second adhesive layer covering the tip of the web; A web tip fixing step for fixing the web to the winding core via the joining member so that the blank portion of the second adhesive layer is positioned at the web tip, and web winding for winding the web around the winding core by rotating the winding core And a removing process.

  In addition, it is preferable to have a cushioning material that can be elastically deformed in a blank portion formed by the second adhesive layer. The cushioning material is preferably formed of an elastic member that is formed thicker than the thickness of the web and deforms below the thickness of the web by winding the web. The web cutting process includes cutting the web tip so that the inclination angle θ1 with respect to the web width direction reference line is within a range of −30 ° <θ1 <30 °. It is preferable that the joining member is attached to the outer peripheral surface so as to be parallel to the web tip.

  According to the present invention, with the blank portion of the web-side adhesive layer of the joining member exposed from the web tip, the web tip is bonded to the web-side adhesive layer, and the web tip is wound around the core via the joining member. Since it is fixing, each adhesion layer of a joining member acts as an elastic member. For this reason, when the next web is wound around the web tip, the joining member functions as a cushioning material, and it is avoided that the next web hits the web tip and is cut off.

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 twice at the film front-end | tip part. It is a perspective view which shows the cross section of the III-III line | wire of FIG. 2 using the joining tape of 2nd Embodiment of this invention. FIG. 3 is a cross-sectional view corresponding to the line III-III in FIG. 2 in a state where the film is wound twice around the film leading end. It is a top view of 3rd Embodiment of this invention which shows the attachment state of the film front-end | tip to a winding core. It is sectional drawing which shows the attachment state to the core of the film tip by the conventional joining 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 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, and 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. At the core replacement position PS2, the polymer film 15 having a predetermined length is wound up, and a predetermined amount of, for example, a fully wound film roll 29 is removed from the winding shaft 22 together with the winding core 23. A new empty winding core 23 is set in 22 and the winding core 23 is exchanged.

  When the polymer film 15 of a predetermined length is wound around the winding core 23 at the winding position PS1, the turret arm 21 rotates 180 degrees when the film roll 29 is almost fully wound, and the winding core replacement position PS2 The film roll 29 close to full winding is positioned. In addition, an empty new winding core 23 is positioned at the winding position PS1. When the film roll 29 reaches a predetermined length, a film cutting device (not shown) is activated 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 film is wound around the film roll 29 at the core replacement position PS2. Further, the leading edge of the cut subsequent film is wound around the empty 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. The film roll 29 thus obtained is rewound by the polymer film 15 and cut into a necessary size, and 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, and the like, and is used as a high function film.

  As shown in FIG. 2, a strip-shaped joining tape (joining member) 31 for fixing the tip portion 15 b of the polymer film 15 to the winding core 23 is attached to the empty winding core 23. The joining tape 31 is affixed to the core outer peripheral surface 23a by a core-side adhesive layer (first adhesive layer) 31b (see FIG. 3).

  As shown in FIG. 3, the bonding tape 31 is composed of a PET (polyethylene terephthalate) belt-like support 31 a on one surface (back surface) and a core-side pressure-sensitive adhesive layer 31 b on the other surface (front surface). (Second adhesive layer) 31c is formed. The thickness of the support 31a is 10 μm or more and 40 μm or less, preferably 10 μm or more and 35 μm or less, more preferably 10 μm or more and 30 μm or less. The core-side adhesive layer 31b may be any material that adheres to the core 23 and the polymer film 15, and is formed on the entire back surface. The thickness is 10 μm or more and 50 μm or less, preferably 10 μm or more and 40 μm or less, more preferably 20 μm or more and 40 μm or less.

  As shown in FIGS. 2 and 3, the film-side adhesive layer 31c is formed on the entire surface of the support 31a and is formed with the same composition and the same thickness as the core-side adhesive layer 31b. It is good also as thickness. Although not shown, a release tape is attached to the surface on which the film-side adhesive layer 31c is formed. The peeling tape is peeled off before the polymer film 15 is wound after the bonding tape 31 is attached to the winding core 23 by the winding core side adhesive layer 31b. As the bonding tape 31, for example, Nitto Denko (model: 5601, 5603, 5605, 5608, 5610, 5612) is used.

  As shown in FIG. 4, when the polymer film 15 is wound and the next film 15 is overlapped with the film tip 15a, the core-side adhesive layer 31b and the film-side adhesive layer 31c of the bonding tape 31 act as cushioning materials. . Therefore, compared with the conventional joining method using the joining tape shown in FIG. 8, the next polymer film that overlaps the film tip has a loosely curved shape, and there is no extreme deformation as in the conventional case, so that surface exposure can be suppressed. .

  The attachment of the bonding tape 31 and the bonding of the film leading end portion 15b with the bonding tape 31 may be performed manually, or an application device having a film cutter 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 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. . Moreover, when performing automatically, the film sticking apparatus is used to cut the polymer film 15 and fix it to the winding core 23. In this case, the bonding tape 31 on the winding core 23 is detected, the polymer film 15 is cut based on the detection timing, the cut film tip 15a is positioned in the blank portion 32, and the film tip 15b is moved to the film. It joins to the side adhesion layer 31c.

  As shown in FIG. 7, the inclination angle θ1 of the film leading end 15a with respect to the reference line BL1 in the film width direction 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 °. This is because, as the inclination angle θ1 is closer to 0 °, the stress due to the influence of the film surface pressure that overlaps the film tip 15a thereafter can be reduced, and thereby the cut-out image can be suppressed.

When the thickness t1 of the bonding tape 31 is t0, the thickness of the polymer film 15 is
(0.5 × t0) ≦ t1 ≦ (1.5 × t0) is preferable. Further, when the thickness of each of the adhesive layers 31b and 31c is t2, it is preferable that (0.4 × t1) ≦ t2 ≦ (0.5 × t1). When the thickness t1 of the joining tape 31 is less than (0.5 × t0), the buffering effect is reduced, and when it exceeds (1.5 × t0), the joining tape is transferred, which is not preferable. Further, when the thickness t2 of each of the adhesive layers 31b and 31c is less than (0.4 × t1), the buffering effect is reduced, and as it approaches (0.5 × t1), the buffering effect is increased, thereby suppressing the cut-out image. can do.

  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 bonding tape 31 in the cylindrical 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. By using such a length L2, it is possible to suppress the cut-out image over the entire film surface.

  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].

  Next, a second embodiment of the present invention will be described with reference to FIGS. In the second embodiment, a bonding tape 41 is used in which a cushioning material 40 is disposed in the blank portion 32 on the front side in the rotational direction of the first embodiment. In addition, the same code | symbol is attached | subjected to the same structural member as 1st Embodiment, and the overlapping description is abbreviate | omitted. As the buffer material 40, a material that is higher than the thickness of the polymer film 15 and is equal to or less than the thickness of the polymer film 15 due to elastic deformation is preferably used. The material of the buffer material 40 is not particularly limited as long as it can be elastically deformed and does not adversely affect the polymer film 15 due to contact. For example, Nitto Denko (model: 5606, 5608), Teraoka Seisakusho (NO.7075), Tesa (NO.4980), etc. are preferably used.

  In the second embodiment, since the cushioning material 40 is attached in a shape protruding upward from the blank portion 32, the film leading edge 15a is pressed against the edge 40a of the cushioning material 40, thereby aligning at the time of joining. Becomes easier. Further, even if the next film 15 is superimposed on the film tip 15 a by winding the film 15, the next film 15 is pushed back by the elastic force of the cushioning material 40. Bending deformation is eliminated, and the occurrence of cut-outs due to the next film 15 being pressed against the film tip 15a is suppressed. Although the buffer material 40 is formed in a band plate shape, the cross-sectional shape is not limited to a rectangle, and may be a semicircular shape, a trapezoidal shape, or any other arbitrary shape.

  As shown in FIG. 7, in the third embodiment, the tip angle 15a of the polymer film 15 is 16 ° with respect to the film width direction reference line BL1. In this case, the bonding tape 31 is also attached to the winding core 23 at the same inclination angle θ1 in accordance with the inclination angle θ1 of the film leading end 15a. Further, when the film leading end 15a is formed with an inclination angle θ1, the bonding tape of the second embodiment is also used by being inclined as in the third embodiment.

  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. However, the present invention is not limited to the polymer film 15 and may be applied to various other webs in which the surface projection is a problem. Can be implemented. In each of the above embodiments, the bonding film 31 is used to bond the polymer film 15 to the winding core 23. However, instead of the bonding tape 31, the film 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 equipment 10 shown in FIG. 1, a TAC film roll 29 having a length of 5000 m, a width of 1500 mm, and a thickness of 80 μm was manufactured. In Example 1, the bonding tape 31 shown in FIGS. 2 and 3 was used, and the film tip 15a was attached as shown in FIG. In Example 2, the same conditions as in Example 1 were used except that the joining tape shown in FIGS. 5 and 6 was used. In Example 3, the film tip tilt angle θ1 shown in FIG. Example 4 was the same as Example 3 except that the film tip inclination angle θ1 of Example 3 was set to 20 °. Example 5 was the same as Example 3 except that the film tip inclination angle θ1 of Example 3 was set to 25 °. Similarly, Example 5 was the same as Example 3 except that the film tip inclination angle θ1 of Example 3 was set to 30 °. In Comparative Example 1, the same conditions as in Example 1 were used except that the film tip 15a was attached to the winding core 23 using the joining tape 4 in the conventional method shown in FIG. Comparative Example 2 was the same as Example 1 except that the film tip inclination angle was 30 ° relative to that of Comparative Example 1.

  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 rewinding by this rewinding, it is possible to observe the leading end of the film that has been wound near the core of the film roll 29. Next, an evaluation test for determining the length at which the cut-out image disappears 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 at which the cut-out image near the winding core disappears was determined.

  When ten film rolls 29 were produced, in each of Examples 1 to 6 with respect to those of Comparative Examples 1 and 2, as shown in Table 1 below, the core portion where the cut-out image was NG It can be seen that the length L3 from 1 is reduced to 1/10 to 1/2 or less, and the cut end failure is improved. 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). Further, in Example 3 in which the cutting line at the film leading end is inclined with respect to the width direction reference line BL1 with an inclination angle θ1 of 16 °, the evaluation result of Example 1 in which other conditions are the same is 40 m with respect to 10 m. And getting longer. Further, in Examples 4 to 6 in which the inclination angle θ1 is increased to 20 °, 25 °, and 30 °, it can be seen that the length L3 at which the cut-out image becomes NG increases as the inclination angle θ1 increases. It can be seen that the closer the angle θ1 is to 0 °, the better.

  In addition, (）) of evaluation in Table 1 means that the film length L3 to be 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 40 m, and the cut-out image is slightly weak, but is OK. (Δ) means that the length L3 is 40 m or more and less than 60 m, and the cut-out image is generated, but it is at a level that is not problematic in practice. (X) means that the length L3 is 60 m or more and the product loss is large and NG.

DESCRIPTION OF SYMBOLS 10 Film roll manufacturing equipment 11 Film manufacturing line 12 Knurling device 13 Winding device 15 Polymer film 23 Core 31 Joining tape 31a Support body 31b Winding side adhesion layer 31c Film side adhesion layer 40 Buffer material 41 Joining tape

Claims (9)

A web roll formed by fixing the leading end of a belt-shaped web to the outer peripheral surface of the winding core with a joining member, and winding the web on the winding core,
The joining member,
A support;
A core-side adhesive layer formed on one surface of the support;
A web-side adhesive layer that is formed on the other surface of the support, covers the web tip, and fixes the web tip to the winding core;
The web tip is bonded to the web side adhesive layer in a state in which the blank portion of the web side adhesive layer is exposed from the tip of the web, and the web tip is fixed to a winding core. Web roll.   The web roll according to claim 1, wherein a cushioning material is disposed in the blank portion.   3. The web roll according to claim 2, wherein the cushioning material is formed of an elastic member that is formed to be thicker than the thickness of the web and is deformed below the thickness of the web by winding the web. The tip of the web is cut so that the inclination angle θ1 with respect to the web width direction reference line falls within the range of −30 ° <θ1 <30 °,
The web roll according to any one of claims 1 to 3, wherein the joining member is attached in parallel to the web tip.   An optical film, wherein the web is cut into a sheet using the web roll according to any one of claims 1 to 4, and the web is an optical film. In a web roll manufacturing method of winding a belt-shaped web around a winding core to manufacture a web roll,
A bonding member having a belt-like support, a first adhesive layer formed on one surface of the support, and a second adhesive layer formed on the other surface of the support is interposed via the first adhesive layer. A bonding member attaching step for fixing to the winding core;
The winding core to which the joining member is affixed is set at a web winding position, a part of the second adhesive layer is covered with a web tip, and a blank part of the second adhesive layer is located at the web tip. And a web tip end fixing step for fixing the web to the winding core via the joining member,
A web roll manufacturing method comprising: a web winding step of rotating the winding core and winding the web around the winding core.   The web roll manufacturing method according to claim 6, further comprising an elastically deformable cushioning material in a blank portion formed by the second adhesive layer.   8. The method of manufacturing a web roll according to claim 7, wherein the cushioning material is formed of an elastic member that is formed to be thicker than the web and deforms below the web thickness by winding the web. A web cutting step of cutting the tip of the web so that an inclination angle θ1 with respect to a reference line in the web width direction is within a range of −30 ° <θ1 <30 °;
The said joining member is affixed so that it may become parallel to the said web front-end | tip with respect to the outer peripheral surface of the said core at the said joining member affixing process. Web roll manufacturing method.

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