JP2013141755A - Knurling roller, apparatus, method for manufacturing web roll and optical film - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent tearing or breaking of polymer films caused by knurling teeth when marks of web travelling direction are formed by knurling.SOLUTION: The knurling teeth 40 formed of many projections are arranged on an outer peripheral surface of a roller body substantially in a matrix so as to form a knurling roller. Knurling tooth rows 41 are formed by the knurling teeth 40 arranged in an axial direction (X direction) of the roller body. Many knurling rows 41 are formed on the outer peripheral surface of the roller body so as to be in the same pitch circumferentially. In each knurling tooth row 41, a gap 42 is formed by eliminating one knurling tooth 40. The mark 33 of web travelling direction is formed by each gap 42. In the knurling tooth rows 41, the number of knurling teeth 40 in the X direction is the same for all the rows. Stress does not concentrate at projection parts formed by the knurling teeth when the mark is formed and tearing or breaking caused by the projections is eliminated.

Description

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

  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 produced in a band shape by a melt film forming method, a solution film forming method, or the like, wound around the winding core in a roll shape, stored as a film roll, and transported. In order to prevent winding deviation and loosening of the polymer film in the film roll, knurling composed of minute irregularities is formed at both ends in the width direction of the polymer film (hereinafter referred to as ears) (for example, Patent Document 1).

  Moreover, in a film roll, in order to detect surface defects, such as a damage | wound of a film, a film is sent out from a film roll, it inspects, and it winds up again. In this case, the film is changed, and the front, rear, left and right of the film are changed. For this reason, even if the film is rewinded, a web traveling direction mark made of an arrow or the like may be provided on one side of the knurling so that both sides and the traveling direction of the film can be identified. (For example, Patent Document 2). By forming the web traveling direction mark on one of the left and right ears, the side is specified. And the advancing direction is specified by making the shape of the mark asymmetric with respect to the advancing direction of the film. Thus, by forming a web advancing direction mark in one ear | edge part, it can utilize as the film-forming side identification mark which can specify the both sides and advancing direction of the web at the time of film forming.

Japanese Patent Laid-Open No. 2002- 211803 JP 2002-210822 A

  However, as in Patent Document 2, when the film-forming side identification mark is formed by the gap portion without the embossing projection, the portion with the mark and the portion without the mark in the circumferential direction of the knurling roller The pressure acting on the film fluctuates, and in the triangular mark part at the tip which becomes the arrow of the arrow, there are fewer protrusions for embossing than other parts, and stress concentrates on this part Become. For this reason, there is a problem that the embossed portion of the film at the stress concentration portion is cracked or that the film is easily torn even if no crack is generated. In particular, in recent years, with the increase in the size and production efficiency of final products such as displays, there is a demand for an increase in the length of the film roll and an increase in the width of the film roll. Therefore, due to the increase in the length and width of the film roll, a depression failure or winding slip is likely to occur in the conventional knurling unevenness amount. For this reason, there is a tendency to increase the amount of unevenness of the knurling, and the increase in the amount of unevenness makes the problem of cracks and tears serious.

  The present invention solves such a problem, and even if a web advancing direction mark for identifying a side during film formation is formed, the web does not cause cracking or tearing. It is an object to provide a roller, an apparatus, and a web roll manufacturing method.

  In the present invention, knurling teeth for imparting knurling to the web are arranged on the outer peripheral surface of the roller body in the axial direction of the roller body to form a knurling tooth row, and the knurling tooth row is arranged in the circumferential direction of the roller body. In each of the knurling rollers arranged at a constant pitch, each knurling tooth row is constituted by a substantially constant number of knurling teeth, and the knurling tooth density is changed by changing the length of the knurling tooth gap of each knurling tooth row. A change portion is formed, and a web advancing direction mark representing the advancing direction of the web is formed using the density changing portion.

  Further, the present invention is a knurling roller having knurling teeth for imparting knurling to a web on an outer circumferential surface of a roller body, wherein the knurling teeth are arranged in a substantially constant number in the axial direction of the roller body, and the outer circumferential surface A knurling tooth row arranged at a constant pitch in the circumferential direction, a knurling tooth density changing portion provided in each knurling tooth row by changing a length of a gap of each knurling tooth, and a density change of the knurling tooth And a web advancing direction mark representing the advancing direction of the web.

  Preferably, the density changing portion is a mark forming gap formed without at least one of the knurling teeth arranged at a constant pitch in the axial direction of the roller body. Further, the density changing portion may be a mark forming high density changing portion formed by adding at least one knurling tooth to the knurling tooth gap, contrary to the mark forming gap. The web advancing direction mark is preferably composed of a V-shape and / or a Y-shape.

  Further, a knurling device of the present invention includes the knurling roller described above, a first knurling roller that forms a knurling having the web traveling direction mark on one side edge portion of the web, and the first knurling roller, A knurling tooth row formed by arranging the same fixed number of knurling teeth in the axial direction of the roller body is arranged in the circumferential direction of the roller body at the same pitch as that of the first knurling roller, and is arranged on the other side edge of the web. And a second knurling roller that forms a knurling.

  The web roll manufacturing method of the present invention is a web roll manufacturing method of winding a continuously manufactured web into a roll shape to manufacture a web roll, and using the knurling device described above, the first knurling roller A knurling forming step of forming a knurling having the web traveling direction mark on one side edge of the web and forming a normal pattern knurling on the other side edge of the web by the second knurling roller; And a web winding process for winding the film into a roll.

  The optical film of the present invention forms a protrusion row by embossing in the width direction of a band-shaped polymer film to form a protrusion row, and the protrusion row is arranged at a constant pitch in the longitudinal direction of the polymer film to form a knurling, In the optical film having both side edges of the polymer film, the density changing portion of the projection row formed by changing the length of the gap of each projection row of the projection row of the knurling formed on the one side edge portion. And a web advancing direction mark that represents the advancing direction of the polymer film formed using the density changing portion of each projection row. The number of protrusions of the protrusion row of the knurling formed on the other side edge is substantially the same as the protrusion row of the one knurling, and the protrusion row is the same as the protrusion row of the one knurling. It is preferable to arrange the knurling of the other side edge portion by arranging them at a pitch.

  According to the present invention, the number of knurling teeth in each knurling tooth row is substantially constant, and when the web traveling direction mark is formed by the knurling tooth arrangement pattern, the force acting on the polymer film by each knurling tooth is constant. To be dispersed. Therefore, stress is not concentrated when a knurling is formed by some knurling teeth. As a result, stress concentration can be avoided, so that there is no occurrence of tearing or cracking in the recesses and protrusions transferred to the web by the knurling teeth.

It is the schematic which shows the film roll manufacturing equipment of this invention. It is a front view of the knurling apparatus seen from the II-II line | wire in FIG. It is a top view of a knurling device. It is a side view of a 1st knurling roller. It is explanatory drawing including the expanded view which shows the position of the knurling pattern of a 1st knurling roller, and the gap for mark formation. It is a top view which shows the polymer film in which the knurling which has a web advancing direction mark was formed. It is an expanded view which shows the knurling pattern of a 2nd knurling roller. It is a perspective view which shows the knurling teeth of a knurling roller. It is a perspective view which shows the knurling of a polymer film. FIG. 10 is an enlarged cross-sectional view taken along line X-X in FIG. 9 showing a knurling protrusion. 6 is a development view of a knurling pattern of Comparative Example 1. FIG. 6 is a development view of a knurling pattern of Comparative Example 2. FIG.

  As shown in FIG. 1, the film roll manufacturing facility 10 of the present invention includes a film manufacturing 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 winding device 13 has a turret arm 16 and winds the polymer film 15 around a winding core 18 set on a winding shaft 17. The turret arm 16 is intermittently rotated 180 degrees by an arm driving unit (not shown), and the winding core 18 is selectively switched between the winding position PS1 and the winding core replacement position PS2. A guide arm 27 is provided at an intermediate position in the rotational direction of the turret arm 16, and a guide roller 28 is attached to the tip of the guide arm 27. The guide roller 28 supports the polymer film 15 so that the polymer film 15 does not contact the turret arm 16 or the arm mounting shaft 29.

  A winding shaft 17 is provided at the tip of the turret arm 16, and a winding core 18 is set on the winding shaft 17. At the winding position PS1, the polymer film 15 sent from the guide roller 26 is wound around the winding core 18. Further, at the winding core replacement position PS2, the film roll 19 which has been fully wound up by winding the polymer film 15 of a certain length is removed from the winding shaft 17 together with the winding core 18, and the winding shaft 17 has a new one. An empty core 18 is set and the core 18 is exchanged.

  When the polymer film 15 having a predetermined length is wound around the winding core 18 at the winding position PS1, and the film roll 19 is almost fully wound, the turret arm 16 is rotated 180 degrees, and the winding core replacement position PS2 is reached. A film roll 19 that is almost fully wound is positioned. An empty winding core 18 is positioned at the winding position PS1. When the film roll 19 reaches a predetermined length, a rewinding device (not shown) is activated to cut the polymer film 15. The rear end portion of the cut preceding film is wound on the film roll 19 at the core replacement position PS2. Further, the leading end portion of the cut subsequent film is wound around the empty core 18 at the winding position PS1.

  Hereinafter, in the same manner, the polymer film 15 is wound around the winding core 18 so that the continuously fed polymer film 15 becomes a product in the form of the film roll 19. The polymer film 15 thus obtained 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.

  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 20, knurling rollers 21 and 22, and shift units 23 and 24. When the knurling is applied, the support roller 20 is raised by the shift portion 23, the knurling rollers 21, 22 are lowered by the shift portion 24, and the rollers 20, 21, 22 move to positions where the polymer film 15 is nipped. When the rollers 20 to 22 move to the film nip position, as shown in FIG. 2, both side edges (ear portions) 15a and 15b of the film are sandwiched between these rollers 20 to 22, and both ear portions 15a and 15b are embossed. The knurlings 30 and 31 are formed. When set at the retracted position, each of the rollers 20 to 22 retracts away from the polymer film 15.

  As shown in FIG. 3, each roller 20, 21, 22 is provided with a heater 25. The heater 25 adjusts the polymer film 15 to an arbitrary temperature. As a result, the knurlings 30 and 31 are applied to both ears 15a and 15b at an appropriate temperature.

  The knurlings 30 and 31 are configured by arranging minute protrusions 32 in a substantially matrix shape. In the present embodiment, the first knurling roller 21 is disposed on the right (hereinafter simply referred to as the right) ear portion 15a in the traveling direction of the polymer film 15 indicated by the arrow A. As shown in FIG. 5, the first knurling roller 21 has a web traveling direction mark 33 on the outer peripheral surface. By this first knurling roller 21, a first knurling 30 having a web traveling direction mark 35 is formed on the right ear portion 15 a of the polymer film 15. The width direction of the polymer film 15 is indicated by an arrow B.

  A second knurling roller 22 is disposed on the left (hereinafter, simply referred to as the left side) ear portion 15 b in the direction of travel of the polymer film 15. The second knurling roller 22 forms a second knurling 31 having a normal pattern in which minute protrusions 32 are arranged in a substantially matrix on the left ear portion 15b of the polymer film 15.

  As shown in FIG. 4, the first knurling roller 21 has a roller body 21a and knurling teeth 40 formed of a plurality of protrusions provided on the outer peripheral surface of the roller body 21a. The support roller 20 includes a roller body 20a having a smooth outer peripheral surface, and no protrusions such as the knurling teeth 40 of the knurling roller 21 are formed.

  In FIG. 5 showing a development view of the outer peripheral surface of the first knurling roller 21, a knurling tooth row 41 is formed on the outer peripheral surface of the roller body 21a in parallel with the axial direction (X direction). The knurling tooth row 41 has a length (L1) that can be formed by arranging ten knurling teeth 40 at a constant pitch P1, and one of the knurling teeth 40 is not formed with the knurling teeth 40. 42. This gap 42 becomes a mark forming gap. In FIG. 5, in order to clarify the gap 42, the gap 42 is indicated by “●”.

  Adjacent knurling teeth 41 are shifted in the axial direction of the roller body 21a by the ½ pitch (P1 / 2) of the knurling teeth 40 (represented by the arrow X, also referred to as the X direction). The knurling tooth row 41 is arranged so that the knurling teeth 40 are staggered. In the present embodiment, the axial direction of the roller body 21a is the row direction (X direction), and the circumferential direction of the roller body 21a is the row direction (shown by arrow Y, also referred to as Y direction). In FIG. 5, 48 rows of knurling teeth 41 are formed at a constant pitch in the Y direction. Further, in the axial direction of the roller main body 21a, the knurling teeth 40 of the adjacent knurling tooth rows 41 are shifted by a half pitch, so that 20 rows of knurling tooth rows 43 are formed.

  In the present invention, the same row position numbers of 1 to 10 are assigned in order to a set of knurling tooth rows 41 that are staggered. In the approximate matrix arrangement specified by the row number and the column number, the position of the mark forming gap 42 is specified by the row number and the column position number. In FIG. 5, the gap position of each knurling tooth row 41 is indicated by “●” on the left side, and the empty column position number (column position number where the gap is located) in each row is displayed on the right side. By forming an empty column position pattern in which the gap position is specified by such row number and column position number, as shown in FIG. 6, the V mark 35a and the Y mark 35b in the film traveling direction (A direction) Are formed in the web traveling direction mark 35 in which are alternately continuous.

  As shown in the development view of FIG. 7, the second knurling roller 22 uses nine knurling teeth 40 and a knurling tooth row 41 arranged at a constant pitch so as to have a width W2 of the second knurling 31. 48 rows are formed, and the knurling teeth 40 are arranged in a substantially matrix shape. Similar to the first knurling roller 21, adjacent knurling teeth 41 are shifted by a half pitch so that the knurling teeth 40 are arranged in a staggered manner.

  As described above, the first knurling 30 having the web advancing direction mark indicating the web advancing direction is formed on one ear portion 15a of the polymer film 15, and the second knurling 31 having a normal pattern is formed on the other ear portion 15b. By doing so, both sides at the time of film formation can be identified by the web traveling direction mark formed on the one ear.

  As shown in FIG. 8, the knurling teeth 40 are formed in a truncated pyramid shape in which the top of the pyramid is cut off parallel to the bottom surface in the present embodiment. In addition, the shape of the knurling teeth may be other than that formed in a truncated pyramid shape, such as a hemisphere, a cylinder, a cone, an elliptical cone, a triangle, a quadrangle, a polygonal pyramid, a polygonal pyramid, and more The top may be cut off.

  As shown in FIG. 9, the minute protrusions 32 transferred to the polymer film 15 by the knurling teeth 40 have a recess 32a transferred by the knurling teeth 40 biting into the film surface, and the periphery is raised together with the recess of the recess 32a. And a rectangular surrounding ridge 32b formed so as to surround the recess 32a with a mountain-shaped cross section, and as shown in FIG. 4, protrudes to the opposite side of the polymer film corresponding to the recess 32a, It is comprised from the substantially convex truncated pyramid-shaped back surface convex part 32c.

  As shown in FIG. 10, the height H1 from the polymer film surface of the surrounding raised portion 32b is preferably 5% or more and 50% or less with respect to the average thickness of the polymer film 15, and is 8% or more and 30% or less. More preferably, it is 15% or more and 25% or less. Moreover, when the height from the back surface of the convex portion of the back surface is H2, the value of H1 / H2 is preferably 0.5 or more and 2 or less, and more preferably 1.0 or more and 1.5 or less. preferable. Further, the pitch P1 (see FIG. 5) of each protrusion of the knurling is preferably 500 μm or more and 5000 μm or less, and more preferably 800 μm or more and 2000 μm or less.

  Next, the operation of this embodiment will be described. As shown in FIGS. 2 to 4, when the knurlings 30 and 31 are applied, the polymer film 15 is sandwiched between the support roller 20 and the knurling rollers 21 and 22. When the knurling teeth 40 bite into the polymer film 15 supported by the support roller 20, the knurling teeth 40 are transferred by the knurling teeth 40 with the irregularities of the knurling teeth 40 reversed and transferred to the polymer film 15. It is formed.

  As shown in FIGS. 4 and 9, on the surface to which the first knurling roller 21 comes into contact, a truncated pyramid-shaped recess 32a due to the biting of the knurling teeth 40, and a surrounding raised portion 32b protruding so as to surround the recessed portion 32a. And are formed. In addition, a convex portion 32c is formed on the surface with which the support roller 20 comes into contact with the concave portion 32a by reaction of the concave portion 32a formed by the biting of the knurling teeth 40. These concave portions 32 a, the surrounding raised portions 32 b, and the convex portions 32 c constitute minute projections 32 that constitute the knurling 30. By the knurlings 30 and 31 in which these minute protrusions 32 are arranged in a substantially matrix shape, slippage between the polymer films 15 that overlap each other at the time of winding is suppressed, and winding deviation and loosening of the film roll 19 are eliminated.

  In addition, since the number of the knurling teeth 40 of each knurling tooth row 41 of the first and second knurling rollers 21 and 22 is the same, and the knurling application width W3 is also the same, the first knurling 30 and the second knurling When forming 31, substantially the same force acts on both ear portions 15 a and 15 b of polymer film 15, and the contact pressure at both ear portions 15 a and 15 b of polymer film 15 can be made substantially constant when knurling is applied. . Therefore, stress concentration on the polymer film 15 is avoided, and no tears or cracks are generated from the protrusions 32. Moreover, since the left and right non-uniform contact does not occur, the occurrence of meandering of the polymer film 15 can be suppressed.

  The web traveling direction mark 35 is formed in the shape of an arrow that indicates the traveling direction by a combination of the V mark 35a and the Y mark 35b, but various patterns other than these can be used as long as the traveling direction can be identified. For example, it can be formed of a V mark and an I mark, a Y mark and an I mark, a V mark, a Y mark, an I mark, or other various patterns.

  The number of the knurling teeth 40 in each knurling tooth row 41 is preferably the same, but there may be a difference in the number that can be regarded as substantially the same. For example, even if an increase / decrease of about 10% of the knurling dentition occurs, if there is no crack or tear at the mark formation portion due to the gap, the increase / decrease range can be treated as substantially the same.

  In the above embodiment, the convex knurling teeth 40 are formed on the knurling rollers 21 and 22, but instead, the same shape as the convex knurling teeth 40 is formed by denting the outer peripheral surface of the roller body. A concave knurling tooth (not shown) may be provided to form a knurling roller. In this case, protrusions can be formed by concave knurling teeth on the ears of the polymer film. Moreover, you may mix a convex knurling tooth and a concave knurling tooth in a knurling roller.

  In the above embodiment, one knurling tooth 40 of the knurling tooth row 41 is deleted, and the web traveling direction mark 33 is formed by a low density portion (gap 42) where the density of the knurling teeth is reduced by this deletion. However, conversely, for example, one knurling tooth 40 is added between each knurling tooth 40 of the knurling tooth row 41 to form a high density portion in which the knurling teeth are arranged at a half pitch in the knurling tooth row. The web traveling direction mark may be formed by the density portion. Also in this case, the total number of knurling teeth of each knurling tooth row is the same, and even if a web traveling direction mark is formed, stress is not concentrated on the mark forming portion at the time of mark transfer, similarly, It is possible to avoid the occurrence of cracks and tears from the protrusions. For example, a high density portion can be formed by adding three knurling teeth 40 arranged at a half pitch at the position of the gap 42 indicated by “●” in FIG. In this case, it is preferable that the number of knurling teeth of the knurling teeth row of the second knurling roller is 12 as the same number as the number of teeth rows of the first knurling roller.

  In the said embodiment, although the knurling apparatus 12 and the winding device 13 were provided in the film production line 11, and the example which implemented this invention in the film roll manufacturing equipment 10 was demonstrated, not only the film roll 19 but a strip | belt-shaped web is used. The present invention can be applied to various web production lines that are continuously produced, and when the web is wound into a roll form, slipping or the like occurs in a portion where the webs overlap and a knurling is imparted.

  The width W1 of the polymer film 15 is not particularly limited, but is preferably 600 mm or more, and more preferably 1400 mm or more and 2500 mm or less. Moreover, it is effective also when the width W1 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. The winding radius of the film roll 19 is preferably 450 mm or more, and more preferably 650 mm or more and 920 mm or less.

The width W2 of the ear portions 15a and 15b of the polymer film 15 is not particularly limited, but is preferably 0.001 to 0.01 times the width W1 of the polymer film 15. The width W3 of the knurlings 30, 31 is preferably 0.1 × 10 ⁻³ times or more and 2.0 × 10 ⁻³ times or less of the width W1 of the polymer film 15. A margin 34 may be provided between the both side edges 15e of the polymer film 15 and the side edges 30a and 31a in the B direction of the knurling, or the margin 34 may be omitted. When the margin 34 is provided, the margin width W4 is preferably 5 × 10 ⁻³ times or less the width W1 of the polymer film 15.

  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, in order to confirm the presence / absence of the effect of the present invention, each knurling is performed using the knurling roller 21 having the arrangement pattern of the knurling teeth 40 shown in FIG. 5 and the knurling roller shown in Patent Document 1. The cracks and tears in the protrusions 32 were observed using a magnifying glass.

Example 1
In the film roll manufacturing equipment 10 shown in FIG. 1, a film roll 19 made of a cellulose acylate film having a length of 5000 m, a width of 1500 mm, and a thickness of 80 μm was manufactured. As the knurling rollers 21 and 22, the length of one side of the truncated surface of the knurling teeth 40 is 250 μm, the length of one side at the base is 800 μm, the height from the base to the truncated surface is 500 μm, and the pitch P1 of the knurling teeth 40 ( 5) was 1400 μm, and the first knurling roller 21 was a knurling roller having the mark pattern shown in FIG. The second knurling roller 22 was a knurling roller having a pattern shown in FIG. The nip pressure between the knurling rollers 21 and 22 and the support roller 20 was 30 N, and the temperature of each of the rollers 20 to 22 was 250 ° C.

(Comparative Examples 1 and 2)
As the first knurling roller, knurling was applied under the same conditions as in Example 1 except that the knurling pattern shown in FIG. 11 was used. The shape and dimensions of the knurling teeth 40 are the same as those in the first embodiment. As the web advancing direction mark 51, the knurling teeth 40 in the mark forming portions are eliminated, and the arrow-shaped advancing direction mark 51 is formed. The number of knurling teeth arranged in the direction was not the same, and a knurling roller having knurling teeth in a state where the number of knurling teeth deleted for mark formation was reduced was used. In the pattern of FIG. 11, the traveling direction mark 51 is formed such that the number of knurling teeth 40 decreases in order of 1, 2, and 3 as the head of the arrow increases. Moreover, the comparative example 2 provided the knurling on the same conditions as Example 1 except having used the knurling pattern which has the web advancing direction mark 52 shown in FIG. As shown in FIG. 12, the arrows indicate that three knurling teeth having the same row position number 5 are arranged in the film running direction, and then the knurling teeth are arranged in the same row in the next knurling tooth row 41 after one interval. A traveling direction mark 52 formed by deleting one at position number 5 was used.

  In the case where the first knurling roller 21 shown in FIG. 5 was used, cracking and tearing did not occur. However, as in Comparative Example 1 in FIG. 11 and Comparative Example 2 in FIG. When the number of protrusions is not within a certain range, the number of protrusions in the knurling row in the axial direction is smaller in the arrow part than in other parts, and stress concentrates on the knurling by the protrusion near the reduced arrow, causing cracks. A tear occurred. This cracking or splitting occurred even when the arrow was constituted by a part of one knurling tooth as shown in FIG.

DESCRIPTION OF SYMBOLS 10 Film roll manufacturing equipment 11 Film manufacturing line 12 Knurling device 13 Winding device 15 Polymer film 15a, 15b Ear part 20 Support roller 21 First knurling roller 22 Second knurling roller 30 First knurling 31 Second knurling 32 Protrusions 33, 35 Web traveling direction mark 35a V mark 35b Y mark 40 Knurling tooth 41 Knurling tooth row 42 Clearance 43 Knurling tooth row

Claims (8)

Knurling teeth for imparting knurling to the web are arranged on the outer peripheral surface of the roller body in the axial direction of the roller body to form a knurling tooth row, and the knurling tooth row is arranged at a constant pitch in the circumferential direction of the roller body. In knurling rollers configured side by side,
Each knurling dentition is composed of a substantially constant number of knurling teeth,
By changing the length of the gap between the knurling teeth of each knurling tooth row, the density changing portion of the knurling teeth is formed,
A knurling roller, wherein a web traveling direction mark representing the traveling direction of the web is formed using the density changing portion. In a knurling roller having knurling teeth for imparting knurling to the web on the outer peripheral surface of the roller body,
The knurling teeth are arranged in a substantially constant number in the axial direction of the roller body, and knurling teeth arranged at a constant pitch in the circumferential direction of the outer peripheral surface;
In each knurling tooth row, the density changing portion of the knurling teeth provided by changing the length of the gap of each knurling tooth,
A knurling roller having a web advancing direction mark formed using the density changing portion of the knurling teeth and indicating a moving direction of the web.   3. The knurling roller according to claim 1, wherein the density changing portion is a mark forming gap formed without at least one of the knurling teeth arranged at a constant pitch in the axial direction of the roller body. .   The knurling roller according to any one of claims 1 to 3, wherein the web traveling direction mark is formed of a V-shape and / or a Y-shape. A first knurling roller comprising the knurling roller according to claim 1, and forming a knurling having the web traveling direction mark on one side edge of the web;
A knurling tooth row in which the same number of knurling teeth as the first knurling roller are arranged in the axial direction of the roller body is arranged in the circumferential direction of the roller body at the same pitch as the first knurling roller, A knurling apparatus comprising a second knurling roller that forms a knurling on the other side edge. In a web roll manufacturing method for winding a continuously manufactured web into a roll, and manufacturing a web roll,
6. The knurling device according to claim 5, wherein a knurling having the web traveling direction mark is formed on one side edge of the web by the first knurling roller, and the other side edge of the web is formed by the second knurling roller. A knurling forming step for forming a knurling of a normal pattern on the part;
A web roll manufacturing method comprising a web winding step of winding the web into a roll. Protrusions are arranged by embossing in the width direction of the band-shaped polymer film to form a protrusion row, the protrusion rows are arranged at a constant pitch in the longitudinal direction of the polymer film to form a knurling, and the knurling is formed on both side edges of the polymer film. In the optical film having
A density changing portion of the projection row formed by changing a length of a gap of each projection of the projection row of the knurling formed on the one side edge portion;
An optical film comprising: a web traveling direction mark representing a traveling direction of the polymer film formed using a density changing portion of each projection row.   The number of projections of the projection row of the knurling formed on the other side edge portion is substantially the same as the number of projection rows of the one knurling, and the projection row has the same pitch as the projection row of the one knurling. The optical film according to claim 7, wherein the optical film is arranged side by side to constitute a knurling of the other side edge.

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