Long strips of resin film that have undergone knurling

Abstract

The present invention aims to provide a long strip of resin film wound into a roll, which can suppress the charge when pulled out until the core portion, thereby suppressing the occurrence of winding deviation and wrinkles during storage, and maintaining high flatness. This problem can be solved by the following long strip of resin film, wherein the long strip of resin film is a long strip of resin film wound into a roll, and the two ends of the film width are knurled. When an observer faces the roll and pulls the film forward from the top of the roll, the knurling at the right end is set as the right knurling, the knurling at the left end is set as the left knurling, the knurling height of the roll core portion of the right knurling is set as Hnbr, the knurling height of the roll core portion of the left knurling is set as Hnbl, the knurling height of the surface portion of the right knurling is set as Hner, and the knurling height of the surface portion of the left knurling is set as Hnel, the following conditions (1) and (2) are satisfied. (1) Hnbr and Hnbl are both 0.5 to 4 μm, (2) Hnbr / Hner and Hnbl / Hnel are both 0.3 to 0.9 μm.

Description

Technical Field

[0001] This invention relates to elongated resin films wound into rolls. More specifically, this invention relates to elongated resin films that have undergone knurling and are wound into rolls. Background Technology

[0002] Previously, it was known that knurling (thickening) the ends of a resin film could achieve stable winding of the resin film and prevent roll deviation and damage to the resin film. However, it is known that even when knurling is performed and the resin film is wound, the knurling is flattened at the core of the roll, and the aforementioned effect cannot be fully realized. To address this, various knurling techniques have been proposed, such as methods for controlling the size of the knurling protrusions (e.g., see Patent Document 1), methods for providing reinforcements in the concave portions (e.g., see Patent Document 2), and methods for setting the knurling in a non-contact manner (e.g., see Patent Document 3), etc.

[0003] On the other hand, resin films are often coated with layers on their surfaces. When the resin film has a high charge, the following problems arise: coating repulsion occurs during coating, coating thickness unevenness increases, and alignment disorder occurs when setting the alignment film of the liquid crystal compound. The charge on the resin film during coating is controlled by removing charge during winding and pulling, but this is insufficient for coatings requiring high precision in recent years. Proposals to address this problem include knurling to suppress relative movement of the wound resin film and suppress its charge (see, for example, Patent Document 4), but this is not sufficiently effective. In particular, even knurled resin films suffer from the following problem: the charge increases closer to the core of the roll, causing coating disorder. Especially in the case of resin films with different compositions on two surfaces, the charge increases during pulling, making it difficult to stably coat the entire rolled resin film due to the above problems, resulting in significant losses.

[0004] Existing technical documents

[0005] Patent Literature

[0006] Patent Document 1: WO11 / 030684

[0007] Patent Document 2: Japanese Patent Application Publication No. 2013-166317

[0008] Patent Document 3: WO10 / 001752

[0009] Patent Document 4: Japanese Patent Application Publication No. 63-74850 Summary of the Invention

[0010] The problem the invention aims to solve

[0011] This invention addresses the problems of the prior art. Specifically, the main objective of this invention is to provide a long strip of resin film that suppresses charging during pull-out up to the core portion, provided it is wound into a roll. Another objective of this invention is to provide a long strip of resin film that suppresses winding misalignment and wrinkling during storage and transport, maintaining high planarity.

[0012] Solution for solving the problem

[0013] The inventors conducted in-depth research to achieve this objective, and as a result, the present invention was completed. A representative example of the present invention is shown below.

[0014] Item 1. A strip-shaped resin film, which is a strip-shaped resin film wound into a roll.

[0015] The two ends of the film width were knurled.

[0016] As the observer faces the roll and pulls the film out from the top of the roll towards their face,

[0017] Set the knurling on the right end to right-side knurling.

[0018] Set the knurling on the left end to left-side knurling.

[0019] Set the knurling height of the knurled core on the right side to Hnbr.

[0020] Set the knurling height of the knurled core on the left side to Hnbl.

[0021] Set the knurling height of the knurled surface layer on the right side to Hner.

[0022] When the knurling height of the knurled surface layer on the left is set to Hnel,

[0023] The following conditions (1) and (2) must be met.

[0024] (1) Both Hnbr and Hnbl are 0.5–4 μm.

[0025] (2) The ratios of Hnbr / Hner and Hnbl / Hnel are 0.3 to 0.9.

[0026] Item 2. The elongated resin film according to Item 1, wherein both Hner and Hnel are 1.2 to 6 μm.

[0027] Item 3. The elongated resin film according to Item 1 or 2, wherein the absolute value of the uniformity of the knurling height of the left and right sides of the core portion, calculated by |(Hnbr-Hnbl) / 〔(Hnbr+Hnbl) / 2〕|, is 0.3 or less.

[0028] Item 4. The elongated resin film according to any one of items 1 to 3, wherein when the outer surface of the elongated resin film is designated as surface A and the inner surface is designated as surface B, the composition of surface A and surface B are different.

[0029] Item 5. The elongated resin film according to any one of items 1 to 4, wherein when the outer surface of the elongated resin film is designated as surface A and the inner surface is designated as surface B, at least one of surface A and surface B is the surface of the first coating.

[0030] Item 6. The elongated resin film according to any one of items 1 to 5, wherein it is a stretched polyester film.

[0031] Item 7. A laminated film having an elongated resin film as described in any one of items 1 to 6, and a second coating disposed on at least one side of the elongated resin film.

[0032] Item 8. The laminated film according to Item 7, wherein the second coating is a hard coating, an anti-glare layer, an anti-reflection layer, a low-reflection layer, an alignment layer, or a phase difference layer.

[0033] Item 9. The laminated film according to Item 7 or 8 is a polarizing protective film or a film for film layer transfer.

[0034] Item 10. A method for manufacturing a laminated thin film, comprising:

[0035] The process of pulling out a strip of resin film according to any one of items 1 to 6 (A); and the process of applying a second coating liquid to at least one side of the pulled-out strip of resin film (B).

[0036] Item 11. The method for manufacturing a laminated thin film according to Item 10, wherein the laminated thin film is a polarizing protective film.

[0037] Item 12. The method for manufacturing a laminated film according to Item 10, wherein the laminated film is a film for film layer transfer.

[0038] The effects of the invention

[0039] Regarding the elongated resin film wound into a roll according to the present invention, the charge carried when the film is pulled out is small up to the core portion. For example, when the film is coated, the repulsion of the coating is small, and a coating with excellent thickness accuracy can be formed up to the end of the film. In addition, the elongated resin film of the present invention can suppress winding deviation and wrinkling after storage and transportation, the film surface is not damaged, and the film has excellent planarity. Detailed Implementation

[0040] (Long strip-shaped resin film)

[0041] The elongated resin film of the present invention is wound into a roll. The resin constituting the elongated resin film (when the elongated resin film has a substrate film and a coating (the first coating described later) provided on at least one side of the substrate film) is not particularly limited, and any resin can be used. Preferably, the resin is polyester, polycyclic olefin, cellulose triacetate, acrylic acid, polycarbonate, polyamide, polyimide, or polypropylene; more preferably, polyester, polycyclic olefin, or cellulose triacetate; and even more preferably, polyester. When polyester is used, polyethylene terephthalate or polyethylene naphthalate is preferred.

[0042] The elongated resin film can be an unstretched film or a stretched film (uniaxially stretched film or biaxially stretched film). The elongated resin film is preferably a stretched film, and particularly preferably a stretched polyester film. It should be noted that, in this specification, "stretched polyester film" is used to mean, including, a film obtained by at least one-sided lamination of a substrate film formed of polyester film followed by a first coating and stretching.

[0043] The minimum width of the elongated resin film is preferably 500 mm, more preferably 800 mm, further preferably 1000 mm, and particularly preferably 1200 mm. The maximum width of the elongated resin film is preferably 4000 mm, more preferably 3500 mm, further preferably 3000 mm, particularly preferably 2700 mm, and most preferably 2500 mm.

[0044] The minimum length of the elongated resin film is preferably 1000m, more preferably 1500m, and even more preferably 2000m. The maximum length of the elongated resin film is preferably 20000m, more preferably 15000m, even more preferably 10000m, and particularly preferably 7000m.

[0045] The lower limit of the thickness of the elongated resin film is preferably 25 μm, more preferably 30 μm, further preferably 35 μm, particularly preferably 40 μm, and most preferably 45 μm. By setting it above this lower limit, wrinkles or winding misalignment can be effectively prevented. The upper limit of the thickness of the elongated resin film is preferably 200 μm, more preferably 150 μm, further preferably 100 μm, particularly preferably 90 μm, and most preferably 80 μm. By setting it below this upper limit, processability becomes easier.

[0046] Regarding elongated resin films, when the outer surface of the film is designated as surface A and the inner surface as surface B, the compositions of surface A and surface B can be the same or different. When the compositions of surface A and surface B are different, the charge on the film tends to increase when it is pulled out. This invention is preferably applied to elongated resin films where the compositions of surface A and surface B are different.

[0047] Examples of situations where the compositions of side A and side B differ include: layering different types of raw material resins through co-extrusion; forming a coating (first coating) only on side A or side B (where one side A and side B is the surface of the first coating, and the other is the surface of the substrate film); and forming coatings with different compositions on both sides A and B (referred to as first coating A and first coating B, respectively) (where side A is the surface of first coating A, and side B is the surface of first coating B). The present invention can be suitably applied in any of these cases. In particular, the present invention is preferably applied to elongated resin films in which the resin compositions of the layers constituting side A and side B differ. Furthermore, the present invention is preferably applied to elongated resin films in which at least one of side A and side B is the surface of the first coating.

[0048] (First coating)

[0049] Examples of preferred first coatings include easy-adhesive layers, easy-slip layers, smoothing layers, hard coatings, and orientation control layers. The first coating can be a single layer or multiple layers (two or more). The first coating can be applied online during film formation or offline after film formation. When the first coating is applied, a long strip-shaped resin film with the knurling of the present invention is produced, including the first coating itself.

[0050] Preferred examples of resins used in the first coating include polyesters, acrylics, polyurethanes (polyester polyurethane, polycarbonate polyurethane, polyether polyurethane, etc.), ethylene-vinyl acetate copolymers, polyamides, styrene-acrylic copolymers, and polyvinyl alcohol. Furthermore, when the first coating is a hard coating, the resin used in the first coating can be a photocurable resin, or a monomer or oligomer containing a double bond.

[0051] The resin used in the first coating preferably contains a crosslinking agent. Preferred examples of crosslinking agents include isocyanates, amino resins such as melamine, oxazoline compounds, and epoxy resins. In the case of a photocurable resin, the crosslinking agent can be a compound (monomer or oligomer) containing multiple double bonds, such as trimethylolpropane triacrylate, pentaerythritol tetraacrylate, acrylic-modified polyurethane, or acrylic-modified epoxy resin.

[0052] The first coating may contain additives. Examples of additives include particles, surfactants, leveling agents, antistatic agents, catalysts, and combinations thereof.

[0053] The lower limit of the thickness of the first coating is preferably 0.001 μm, more preferably 0.005 μm, even more preferably 0.01 μm, and particularly preferably 0.02 μm. The upper limit of the thickness of the first coating is preferably 10 μm, more preferably 5 μm, even more preferably 3 μm, particularly preferably 2 μm, and most preferably 1 μm.

[0054] (Knurling)

[0055] The elongated resin film preferably has knurled sections at both ends of its width, and is preferably rolled into a roll after knurling. The knurling method is not particularly limited, and examples include: pressing a knurling tool to deform the film; irradiating a laser to create raised areas around holes; and using inkjet printing or similar methods to create dots of UV-curable resin or hot-melt resin. These methods allow for the creation of dotted protrusions on the film surface.

[0056] "The two ends of the film width" refers to the area within 50 mm (or within 10% of the total width when the total width is less than 500 mm) starting from each end in the film width direction. The lower limit of the distance between the end in the film width direction and the knurling position (the edge of the film end side of the knurled section) is preferably 0.5 mm on both the right and left sides, more preferably 1 mm. The upper limit of the distance between the end in the film width direction and the knurling position is preferably 20 mm on both the right and left sides, more preferably 15 mm, and even more preferably 10 mm. By setting these ranges, stable knurling can be performed on both ends in the film width direction, and the effective width of the film can be ensured.

[0057] The lower limit of the width of the knurling section is preferably 3 mm, more preferably 5 mm, and even more preferably 7 mm. By setting it above this lower limit, the knurling is less likely to be flattened. The upper limit of the width of the knurling section is preferably 30 mm, more preferably 25 mm, and even more preferably 20 mm. By setting it below this upper limit, the degree of knurling flattening can be optimized, and the effective width of the film can be ensured.

[0058] The lower limit of the spacing between the protrusions of the knurled part (e.g., the spacing in the width or length direction) is preferably 0.5 mm, more preferably 0.6 mm, and even more preferably 0.7 mm. The upper limit of the spacing between the protrusions of the knurled part is preferably 3 mm, more preferably 2.5 mm, even more preferably 2 mm, and particularly preferably 1.5 mm. It should be noted that the spacing between the protrusions of the knurled part is the spacing between the center points of the protrusions. In the case of hot knurling described later, a ridge can be formed around the protrusion to match the protruding shape of the knurling tool. For example, the spacing between the centers of a quadrilateral ridge can be set as the spacing between the protrusions.

[0059] The lower limit of the density of the protrusions in the knurled part is preferably 10 pieces / cm. 2 More preferably 15 per cm 2 Further optimized to 25 per cm 2 The preferred size is 40 pieces / cm. 2 The optimal value is 60 per cm. 2 The upper limit of the density of the protrusions in the knurled part is preferably 400 per cm. 2 More preferably 300 per cm 2 Further optimized to 250 pieces / cm 2 The flattening ease of knurling can be adjusted by utilizing the density of the protrusions in the knurling process. By setting it within the aforementioned range, the flattening ease can be easily adjusted using a relatively simple knurling process.

[0060] The configuration of the protrusions in the knurling part can be, for example, any of the following: a configuration in which they are neatly arranged along the longitudinal and transverse directions, an alternating configuration in which adjacent protrusions and concaves are staggered by half a cycle, or an oblique configuration in which adjacent protrusions and concaves are staggered by 1 / 3 or 1 / 4.

[0061] (Knurling knife)

[0062] As an example of knurling, a method for deforming a film by pressing it with a knurling knife, which is commonly practiced, will be described in detail, but the present invention is not limited thereto.

[0063] The knurling cutter is preferably made of metal. Examples of metals include SUS, stainless steel, aluminum, titanium, and hard chrome. The surface of the knurling cutter can be plated.

[0064] The lower limit of the diameter of the knurling cutter is preferably 3 cm, more preferably 5 cm. The upper limit of the diameter of the knurling cutter is preferably 30 cm, more preferably 25 cm, and even more preferably 20 cm. By setting it within the above range, a knurling processing device of appropriate size can be manufactured.

[0065] The minimum thickness of the knurling cutter is preferably 3 mm, more preferably 5 mm, and even more preferably 7 mm. The maximum thickness of the knurling cutter is preferably 50 mm, more preferably 40 mm, and even more preferably 30 mm.

[0066] On the outer periphery of the knurling cutter, a protrusion is provided to match the configuration of the given protrusion. The lower limit of the height of the protrusion is preferably 0.05 mm, more preferably 0.1 mm, further preferably 0.15 mm, and particularly preferably 0.2 mm. The upper limit of the height of the protrusion is preferably 3 mm, more preferably 2.5 mm, further preferably 2 mm, and particularly preferably 1.5 mm.

[0067] Viewed from above, the protrusions can take various shapes, including circles, ovals, triangles, squares, rectangles, rhombuses, trapezoids, pentagons, hexagons, and polygons with more than six sides. Squares, rectangles, and rhombuses are preferred. Furthermore, as a three-dimensional shape, it can be a cone, a multi-faceted pyramid, or a truncated cone, a truncated multi-faceted pyramid, etc. Knurling on truncated cones tends to be less prone to flattening.

[0068] When the protrusion is a truncated cone shape, the total area of ​​the flat portion of the upper surface of the protrusion is preferably 1% or more, more preferably 3% or more, and even more preferably 5% or more, relative to the area of ​​the outer periphery of the knurling cutter where the protrusion is provided. This total area is preferably 50% or less, more preferably 40% or less, and even more preferably 30% or less, relative to the area of ​​the outer periphery of the knurling cutter where the protrusion is provided. By setting it within the above range, the effect of the truncated cone shape can be more reliably achieved.

[0069] (Knurling processing conditions)

[0070] Knurling can be performed, for example, by using two knurling blades to hold the film and applying the knurling to both sides. In this case, the two knurling blades can be a set of knurling blades where the blades interlock with each other, or a set of knurling blades that do not interlock and perform the knurling independently. Alternatively, knurling can also be performed, for example, by using a knurling blade and a smooth roller to hold the film and applying the knurling to only one side of the film.

[0071] The knurling process is preferably performed by pressing the film against a knurling blade. The knurling height can be adjusted using this pressing force. The lower limit of the pressing force is preferably 20 N, more preferably 40 N, and even more preferably 50 N. The upper limit of the pressing force is preferably 2000 N, more preferably 1500 N, and even more preferably 1000 N. By setting these ranges, knurling can be performed without excessive use of the equipment. It should be noted that pressing can be performed by moving either the knurling blade assembly or either the knurling blade or the smoothing roller, or by moving both.

[0072] Knurling based on a knurling tool can be performed without heating the tool (cold knurling) or by heating the tool to above the softening temperature of the film (e.g., glass transition temperature (Tg)) (hot knurling). Hot knurling tends to result in knurling that is not easily flattened.

[0073] The surface temperature of the knurling tool is preferably 10°C or higher, more preferably 20°C or higher. In the case of hot knurling, the surface temperature of the knurling tool is preferably ≥ the Tg of the film, more preferably ≥ (Tg+20°C), and even more preferably ≥ (Tg+50°C). The surface temperature of the knurling tool is preferably below the melting point of the film, more preferably below (melting point-10°C), and even more preferably below (melting point-20°C). By setting it within the above range, efficient knurling can be achieved, and the formation of whiskers due to resin melting in the knurling section can be suppressed, as can the wavy state of the film in the knurling section.

[0074] Specifically, in the case of polyethylene terephthalate films (including films in which a first coating is provided on at least one side of a substrate film formed from polyethylene terephthalate film, films obtained by stretching them, etc.), the surface temperature of the knurling knife is preferably 80 to 250°C, more preferably 100 to 240°C, and even more preferably 120 to 230°C.

[0075] Methods for increasing the surface temperature of a knurling cutter include, for example, flowing a heating fluid such as oil into the cutter; and methods based on induction heating, infrared heating, or hot air. Alternatively, the portion of the film to be knurled (the end of the film) can be preheated using infrared radiation or hot air.

[0076] The lower limit of the knurling speed is preferably 20 m / min, more preferably 30 m / min, and even more preferably 50 m / min. The upper limit of the knurling speed is preferably 800 m / min, more preferably 600 m / min, and even more preferably 500 m / min. By setting the speed within the above range, high-productivity knurling can be achieved, and stable knurling can be achieved under appropriate conditions. It should be noted that the knurling speed is limited by the processing speed associated with knurling processes such as slit knurling and coating.

[0077] The knurling height can be adjusted by adjusting the pressing pressure of the knurling cutter, the surface temperature of the knurling cutter, and the knurling speed.

[0078] (Initial knurling height)

[0079] The lower limit of the knurling height (initial knurling height) immediately after knurling is preferably 1.5 μm, more preferably 2 μm, and even more preferably 2.5 μm. The upper limit of the knurling height immediately after knurling is preferably 15 μm, more preferably 12 μm, even more preferably 10 μm, particularly preferably 7 μm, and most preferably 6 μm.

[0080] The knurling process, when freshly completed, results in areas that are easily flattened when rolled into a roll. This is because, in cold knurling, the film is pressed against the opposite side of the knurling blade by its protrusions, thus forming the knurling. However, even the extruded knurling has areas that are easily dented by pressure. In hot knurling, resin bulges form around the protrusions of the knurling blade, but these bulges are not uniformly high; rather, they are uneven in height. Therefore, the higher bulges are easily flattened even under low pressure.

[0081] Therefore, immediately after being wound into a roll, the initial knurling height is determined using a sample taken from the outermost film. Furthermore, considering the above, the initial knurling height is preferably adjusted such that the knurling heights of the surface layer and the core portion fall within the range described later.

[0082] (Roll-up)

[0083] The elongated resin film is preferably wound into a roll on a cylindrical core. The lower limit of the winding tension is preferably 50 N / m, more preferably 60 N / m, further preferably 70 N / m, particularly preferably 80 N / m, and most preferably 90 N / m. The upper limit of the winding tension is preferably 330 N / m, more preferably 300 N / m, further preferably 270 N / m, particularly preferably 250 N / m, and most preferably 230 N / m. By setting these ranges, the degree of knurling and flattening can be optimized, and winding misalignment, wrinkles, and deterioration of flatness during storage can be prevented.

[0084] During winding, it is preferable to remove trapped air while simultaneously contacting the contact roller. In this case, the lower limit of the winding contact pressure of the contact roller is preferably 30 N / m, more preferably 40 N / m, further preferably 50 N / m, and particularly preferably 60 N / m. The upper limit of the winding contact pressure is preferably 600 N / m, more preferably 500 N / m, further preferably 400 N / m, and particularly preferably 300 N / m. By setting these ranges, the degree of knurling and flattening can be optimized, and winding misalignment, wrinkles, and deterioration of flatness during storage can be prevented.

[0085] (Knurling height of a long strip of resin film wound into a roll)

[0086] In this instruction manual, the right side, left side, surface layer, and core layer are shown below.

[0087] Right side: The right end of the film as the observer faces the roll and pulls it out from the top of the roll towards the front.

[0088] Left side: The left end of the film as the observer faces the roll and pulls it out from the top of the roll towards the front.

[0089] Surface layer: The portion located 100±1m from the end point of the winding of the film (or, if the total length of the film is less than 1000m, approximately 10% of the total length of the film).

[0090] Core portion: The portion located 100±1m from the starting point of the winding of the film into a roll (or, if the total length of the film is less than 1000m, approximately 10% of the total length of the film).

[0091] The abbreviations for the knurling height of each part are shown below.

[0092] Knurling height on the right side of the surface layer: Hner

[0093] Knurling height on the left side of the surface layer: Hnel

[0094] It should be noted that Hne is not specifically limited to left or right, and indicates the knurling height of the surface layer.

[0095] Knurling height on the right side of the core: Hnbr

[0096] Knurling height on the left side of the core: Hnbl

[0097] It should be noted that Hnb does not specifically limit left and right, but indicates the knurling height of the core.

[0098] The lower limit of the knurling height (both Hnbr and Hnbl) of the core portion is preferably 0.5 μm, more preferably 0.7 μm, further preferably 0.9 μm, particularly preferably 1 μm, and most preferably 1.1 μm. The upper limit of the knurling height (both Hnbr and Hnbl) of the core portion is preferably 4 μm, more preferably 3.5 μm, further preferably 3.2 μm, and particularly preferably 3 μm.

[0099] The lower limit of the knurling height (both Hner and Hnel) of the surface layer is preferably 1.2 μm, more preferably 1.3 μm, further preferably 1.4 μm, particularly preferably 1.5 μm, and most preferably 1.6 μm. The upper limit of the knurling height (both Hner and Hnel) of the surface layer is preferably 6 μm, more preferably 5 μm, further preferably 4 μm, particularly preferably 3.7 μm, and most preferably 3.5 μm.

[0100] It should be noted that the flattening of the knurling generally stabilizes about one month after being rolled into a roll. Therefore, the knurling height of the core and surface layers is preferably measured on the product obtained one month after being rolled into a roll. The knurling height of the core and surface layers can be set within the above range based on the type of knurling, initial knurling height, knurling shape, knurling width, roll tension, winding contact pressure, roll length, etc.

[0101] The lower limit of the knurling residual rate (Hnb / Hne) [both the right-side knurling residual rate (Hnbr / Hner) and the left-side knurling residual rate (Hnbl / Hnel)] is preferably 0.3, more preferably 0.35, further preferably 0.4, and particularly preferably 0.45. The upper limit of the knurling residual rate (Hnb / Hne) [both Hnbr / Hner and Hnbl / Hnel] is preferably 0.9, more preferably 0.85, further preferably 0.8, particularly preferably 0.75, and most preferably 0.7. The knurling residual rate can be set within the above range depending on the type of knurling, initial knurling height, knurling shape, knurling width, knurling height uniformity, roll tension, roll length, etc.

[0102] The lower limit of the knurling reduction (Hne-Hnb) [both the right-side knurling reduction (Hner-Hnbr) and the left-side knurling reduction (Hnel-Hnbl)] is preferably 0.2 μm, more preferably 0.23 μm, further preferably 0.25 μm, particularly preferably 0.28 μm, and most preferably 0.3 μm. The upper limit of the knurling reduction (Hne-Hnb) [both Hner-Hnbr and Hnel-Hnbl] is preferably 3 μm, more preferably 2.7 μm, further preferably 2.5 μm, particularly preferably 2.2 μm, and most preferably 2 μm. The knurling reduction can be set within the above range depending on the type of knurling, initial knurling height, knurling shape, knurling width, knurling height uniformity, roll tension, roll length, etc.

[0103] By setting the knurling height, knurling residue rate, and knurling reduction amount in the core portion to the aforementioned ranges, it is possible to reduce the pull-out charge, prevent damage to the film surface, prevent winding misalignment and wrinkles, and ensure flatness. These effects can be further improved by setting the knurling height, knurling residue rate, and knurling reduction amount in the surface portion to the aforementioned ranges as well.

[0104] The lower limit of the absolute value of the uniformity of knurling height on the left and right sides of the core (|(Hnbr-Hnbl) / 〔(Hnbr+Hnbl) / 2〕|) is preferably 0, more preferably 0.01, and the upper limit is preferably 0.3, more preferably 0.25, further preferably 0.2, and particularly preferably 0.15.

[0105] The lower limit of the absolute value of the uniformity of knurling height on the left and right sides of the surface layer (|(Hner-Hnel) / 〔(Hner+Hnel) / 2〕|) is preferably 0, more preferably 0.01, the upper limit is preferably 0.3, more preferably 0.25, further preferably 0.2, and particularly preferably 0.15.

[0106] By setting the uniformity of the knurling height on the left and right sides of the core and surface portions to the range described above, it is possible to further reduce the pull-out charge, further prevent damage to the film surface, winding deviation, and wrinkles, further ensure flatness, and prevent bending and slack when pulling the film out of the roll and processing it.

[0107] The knurling height can easily vary from side to side due to differences in the film's length in the width direction, differences in physical properties such as elastic modulus, and differences in tension in the width direction during winding. By precisely controlling the parallelism of the conveyor rollers and other components until the film is wound, and by controlling the temperature and other parameters in a way that prevents differences in physical properties during film production such as stretching and heat setting, the absolute value of the knurling height uniformity can be reduced.

[0108] Regarding the long strip resin film wound into a roll according to the present invention, the charge carried during the pulling is maintained at a low level up to the core portion. Therefore, when processing such as coating after pulling, it is not easy to cause rejection of the coating liquid or uneven thickness, and a defect-free coating film can be obtained.

[0109] (Pull out the charged part)

[0110] The upper limit of the pull-out charge of the core portion, in absolute value, is preferably 25 kV, more preferably 20 kV, further preferably 15 kV, and particularly preferably 12 kV. The lower limit of the pull-out charge of the core portion, in absolute value, is preferably 0.1 kV, more preferably 0.5 kV. It should be noted that the pull-out charge refers to the charge on the central portion of the film in the width direction immediately after it has been pulled out at 100 m / min.

[0111] (Laminated thin film)

[0112] The elongated resin film of the present invention is preferably used as a raw material for setting each functional layer and processed into a laminated film.

[0113] The laminated film of the present invention preferably comprises an elongated resin film and a second coating (a coating obtained by coating with a coating liquid and laminating) disposed on at least one side of the elongated resin film. The manufacturing method of the laminated film preferably includes: a step (A) of pulling out the elongated resin film; and a step (B) of coating at least one side of the pulled-out elongated resin film with a coating liquid for the second coating. The laminated film can be rolled into a roll after the second coating is laminated on at least one side of the elongated resin film, or it can be cut to a predetermined size after the second coating is laminated (without being rolled into a roll).

[0114] When using a coating liquid for the second coating layer, if the resin is a polyester, acrylic resin, polyurethane (e.g., polyester polyurethane, polycarbonate polyurethane, polyether polyurethane), ethylene vinyl acetate copolymer, polyamide, styrene acrylic copolymer, polyvinyl alcohol, or a radiation-curable coating, then acrylic monomers, acrylic oligomers, or polymerizable liquid crystal compounds are preferred. Among these, acrylic monomers, acrylic oligomers, and polymerizable liquid crystal compounds are particularly preferred.

[0115] The solvent for the coating liquid used in the second coating layer is preferably an aromatic hydrocarbon such as toluene, an alcohol, a ketone, or an ester. If the coating liquid is radiation-curable, no solvent is required.

[0116] The lower limit of the thickness of the second coating (the thickness of the resulting coating after drying) is preferably 0.001 μm, more preferably 0.005 μm, even more preferably 0.01 μm, and particularly preferably 0.02 μm. The upper limit of the coating thickness is preferably 20 μm, more preferably 15 μm, even more preferably 10 μm, particularly preferably 7 μm, and most preferably 5 μm.

[0117] The second coating (the resulting coating film) is preferably an optical functional layer such as a hard coating, an anti-glare layer, an anti-reflection layer, a low-reflection layer, an alignment layer (e.g., a light alignment layer), or a retardation layer (e.g., a λ / 4 retardation layer or a λ / 2 retardation layer). Alternatively, the second coating can be, for example, an adhesive or bonding agent. The second coating can be a single layer or a multilayer consisting of two or more layers (e.g., an alignment layer and a retardation layer).

[0118] The surface of the second coating does not necessarily need to have the same characteristics as the surface of the elongated resin film of the present invention. Furthermore, the laminated film can be obtained by cutting the two ends (knurled portions) of the film width. It should be noted that even if the elongated resin film itself does not have a first coating, the coating laminated on the elongated resin film is referred to as the second coating.

[0119] Preferred applications for laminated thin films include: anti-glare films, low-reflection films, anti-reflection films, transparent conductive film substrates, polarizer protective films, phase retardation films formed by liquid crystal compounds as phase retardation layers, and films for transferring these functional layers.

[0120] Example

[0121] (1) Knurling height

[0122] A digital micrometer (Sony Manufacturing Systems, μ-mate M-30) was used.

[0123] For the central portion of the knurling width, 10 measurements are taken along the MD (also known as the flow direction, length direction, longitudinal direction, etc.) at intervals of approximately 5 cm, and the average value is set as the "knurling thickness". For the inner side of the film about 1 cm away from the center edge of the knurling part, 10 measurements are taken along the MD at intervals of approximately 5 cm, and the average value is set as the "film thickness". The "knurling thickness - film thickness" is set as the knurling height.

[0124] The measurements were performed as follows: The film, which had been rolled up and stored at room temperature for one month, was pulled out, and measurements were taken at four locations on the right and left sides of the film, including the surface layer and the core layer.

[0125] It should be noted that the right side, left side, surface layer, and core layer are shown below.

[0126] Right side: The right end of the film as the observer faces the roll and pulls it out from the top of the roll towards the front.

[0127] Left side: The left end of the film as the observer faces the roll and pulls it out from the top of the roll towards the front.

[0128] Surface layer: The portion 100m from the end point of the winding of the film into a roll.

[0129] Core section: The part located 100m from the starting point of the winding of the film into a roll.

[0130] The abbreviations for the knurling height of each part are shown below.

[0131] Knurling height on the right side of the surface layer: Hner

[0132] Knurling height on the left side of the surface layer: Hnel

[0133] Knurling height on the right side of the core: Hnbr

[0134] Knurling height on the left side of the core: Hnbl

[0135] (2) Knurling Residue Rate

[0136] As shown below.

[0137] Knurling residue on the right side: Hnbr / Hner

[0138] Left side knurling residue rate: Hnbl / Hnel

[0139] (3) Knurling reduction

[0140] As shown below.

[0141] Right side knurling reduction: Hner-Hnbr

[0142] Left knurling reduction: Hnel-Hnbl

[0143] (4) Uniformity of knurling height

[0144] As shown below.

[0145] Uniformity of knurling height between left and right sides of the core: Absolute value of (Hnbr-Hnbl) / 〔(Hnbr+Hnbl) / 2〕

[0146] Uniformity of knurling height on the left and right sides of the surface layer: Absolute value of (Hner-Hnel) / 〔(Hner+Hnel) / 2〕

[0147] (5) Pull out the charged part

[0148] A roll of film, stored at room temperature for one month, is pulled out from the surface at a speed of 100 m / min, and the charge on the film in the center of the core is measured. The measurement is performed using a Kasuga Electric KSD-0103, measuring the portion immediately after peeling from the film roll.

[0149] (6) Winding offset

[0150] Observe the end face of the rolled film after it has been stored at room temperature for one month.

[0151] ◎: It is in the same state as when it was just rolled up, with no bumps or unevenness.

[0152] ○: Slightly increased unevenness or bamboo shoot-like deformation was observed.

[0153] △: Increased unevenness or bamboo shoot-like deformation is observed, but it is at a level that does not pose a problem in practical use.

[0154] ×: An increase in unevenness or bamboo shoot-like deformation at a level that is not practically usable is observed.

[0155] (7) Wrinkles

[0156] After being stored at room temperature for one month, the rolled film is pulled out and the wrinkles along its entire length are observed.

[0157] ◎: Completely wrinkle-free.

[0158] ○: Slight wrinkles are observed along a portion of the entire length.

[0159] △: Fragile wrinkles were observed along a portion of the entire length, but the level was not problematic.

[0160] ×: Horizontal wrinkles that are not practically usable are observed in a portion of the total length.

[0161] (8) Thin film planarity

[0162] After being stored at room temperature for one month, the rolled film was pulled out, and a 3-meter section was cut from a point 80-90 mm from the surface. This section was placed on a matte black table with a flat top, and its flatness was evaluated by observing the shape of the fluorescent light reflected from the ceiling on the film. It should be noted that this was compared with the flatness of the film immediately after it was rolled up.

[0163] ◎: No different from the sample just rolled up.

[0164] ○: The flatness deteriorates slightly.

[0165] △: The planarity has deteriorated, but it is still at a level where there are no problems.

[0166] ×: The flatness has deteriorated to a level that is practically unusable.

[0167] (Manufacturing of the easy-to-adhere component for the first coating layer)

[0168] (Polymerization of polyester resin)

[0169] A transesterification reaction was carried out in a stainless steel autoclave equipped with a stirrer, thermometer, and partial reflux condenser, consisting of 194.2 parts by weight of dimethyl terephthalate, 184.5 parts by weight of dimethyl phthalate, 14.8 parts by weight of sodium dimethyl isophthalate-5-sulfonate, 233.5 parts by weight of diethylene glycol, 136.6 parts by weight of ethylene glycol, and 0.2 parts by weight of tetrabutyl titanate. The reaction mixture was heated to 255°C, and the reaction system was slowly depressurized. The reaction was then carried out under a reduced pressure of 30 Pa for 1 hour and 30 minutes to obtain a copolyester resin. The obtained copolyester resin was pale yellow and transparent. The specific viscosity of the copolyester resin was measured to be 0.70 dl / g. The glass transition temperature based on DSC was 40°C.

[0170] (Preparation of polyester aqueous dispersion)

[0171] 30 parts by mass of polyester resin and 15 parts by mass of ethylene glycol n-butyl ether were added to a reactor equipped with a stirrer, thermometer, and reflux device. The resin was dissolved by heating and stirring at 110°C. After the resin was completely dissolved, 55 parts by mass of water were slowly added while stirring the polyester solution. After the addition was completed, the mixture was cooled to room temperature while stirring to obtain a milky white polyester aqueous dispersion with a solid content of 30% by mass.

[0172] (Preparation of polyvinyl alcohol aqueous solution)

[0173] Add 90 parts by weight of water to a container equipped with a stirrer and a thermometer. While stirring, slowly add 10 parts by weight of polyvinyl alcohol resin (manufactured by KURARAY, degree of polymerization 500 and degree of saponification 74%). After the addition is complete, heat the mixture to 95°C while stirring to dissolve the resin. After the resin has dissolved, cool the mixture to room temperature while stirring to obtain a polyvinyl alcohol aqueous solution with a solid content of 10% by weight.

[0174] (Preparation of the end-capped polyisocyanate crosslinking agent used in the easily bondable layer P1)

[0175] 100 parts by mass of a polyisocyanate compound with an isocyanurate structure (manufactured by Asahi Kasei Chemicals, DURANATE TPA) using hexamethylene diisocyanate as a raw material, 55 parts by mass of propylene glycol monomethyl ether acetate, and 30 parts by mass of polyethylene glycol monomethyl ether (average molecular weight 750) were added to a flask equipped with a stirrer, thermometer, and reflux condenser. The mixture was kept at 70°C for 4 hours under a nitrogen atmosphere. Subsequently, the temperature of the reaction solution was lowered to 50°C, and 47 parts by mass of methyl ethyl ketone oxime were added dropwise. The infrared spectrum of the reaction solution was measured, confirming that the absorption of the isocyanate groups had disappeared. Water was then added to obtain a capped polyisocyanate aqueous dispersion with a solid content of 40% by mass.

[0176] (Preparation of coating solution for easy-to-adhere layer P1)

[0177] Mix the following ingredients to prepare the coating solution for P1.

[0178]

[0179] (Preparation of the polyurethane resin used in the easy-to-bond layer P2)

[0180] The following steps were used to prepare a polyurethane resin with aliphatic polycarbonate polyols as constituent components. 43.75 parts by weight of 4,4-diphenylmethane diisocyanate, 12.85 parts by weight of dimethylolbutyric acid, 153.41 parts by weight of polyhexamethylene carbonate diol with a number average molecular weight of 2000, 0.03 parts by weight of dibutyltin dilaurate, and 84.00 parts by weight of acetone as a solvent were added to a four-necked flask equipped with a stirrer, a serpentine condenser, a nitrogen inlet tube, a silica gel drying tube, and a thermometer. The mixture was stirred at 75°C for 3 hours under a nitrogen atmosphere to confirm that the reaction solution reached the specified amine equivalent. Next, the temperature of the reaction solution was lowered to 40°C, and 8.77 parts by weight of triethylamine were added to obtain a polyurethane prepolymer solution. Then, 450 g of water was added to a reaction vessel equipped with a high-speed homogenizer, the temperature was adjusted to 25°C, and the water was stirred at a speed of 2000 min… -1The mixture was stirred and mixed while adding the polyurethane prepolymer solution to disperse it. Then, acetone and a portion of the water were removed from the mixture under reduced pressure to prepare a water-soluble polyurethane resin (polyurethane resin aqueous solution) with a solids content of 35%. The resulting polyurethane resin, with aliphatic polycarbonate polyol as a constituent component, had a glass transition temperature of -30°C.

[0181] (Preparation of the oxazoline-based crosslinking agent used in the easily bonded layer P2)

[0182] A mixture of 58 parts by mass of ion-exchanged water and 58 parts by mass of isopropanol, serving as the aqueous medium, and 4 parts by mass of polymerization initiator (2,2'-azobis(2-amidinylpropane) dihydrochloride) was added to a flask equipped with a thermometer, a nitrogen inlet tube, a reflux condenser, a dropping funnel, and a stirrer. Meanwhile, a mixture of 16 parts by mass of 2-isopropenyl-2-oxazoline, a polymerizable unsaturated monomer with an oxazoline group, 32 parts by mass of methoxy polyethylene glycol acrylate (with an average addition molar number of 9 mol of ethylene glycol, manufactured by Shin-Nakamura Chemical Co., Ltd.), and 32 parts by mass of methyl methacrylate was added dropwise to the dropping funnel at 70°C for 1 hour under a nitrogen atmosphere. After the addition was complete, the reaction solution was stirred for 9 hours and cooled to obtain a water-soluble resin with an oxazoline group (an aqueous solution of an oxazoline-based crosslinking agent) with a solid content concentration of 40% by mass.

[0183] (Preparation of coating solution for easy-to-adhere layer P2)

[0184] Mix the following raw materials to prepare a coating liquid for P2, which is used to form a coating layer with excellent adhesion to the functional layer.

[0185]

[0186]

[0187] (Manufacturing of polyester resin for substrate film)

[0188] The esterification reactor was heated to 200°C, and 86.4 parts by mass of terephthalic acid and 64.6 parts by mass of ethylene glycol were added. While stirring, 0.017 parts by mass of antimony trioxide, 0.064 parts by mass of magnesium acetate tetrahydrate, and 0.16 parts by mass of triethylamine were added as catalysts. Next, the reactor was pressurized and heated to 240°C at a gauge pressure of 0.34 MPa. After the pressurized esterification reaction, the reactor was returned to atmospheric pressure, and 0.014 parts by mass of phosphoric acid were added. Then, the temperature was raised to 260°C over 15 minutes, and 0.012 parts by mass of trimethyl phosphate were added. After 15 minutes, the mixture was dispersed using a high-pressure disperser. After another 15 minutes, the resulting esterification product was transferred to a polycondensation reactor and subjected to polycondensation at 280°C under reduced pressure.

[0189] After the polycondensation reaction, the product was filtered using a Naslon filter with a 95% diameter cutoff of 5 μm. It was then extruded from a nozzle in a filament form, cooled and solidified using pre-filtered cooling water (pore size: less than 1 μm), and cut into granules. The resulting polyethylene terephthalate resin had an intrinsic viscosity of 0.68 dL / g and was essentially free of inactive particles and internally precipitated particles (hereinafter abbreviated as PET). It should be noted that the intrinsic viscosity was measured using a phenol / tetrachloroethane = 60 / 40 (mass ratio) solution and assuming a Huggins constant of 0.38.

[0190] (Manufacturing of Thin Film A)

[0191] As a film raw material, PET granules were dried under reduced pressure at 135°C for 6 hours (1 Torr) and then fed into an extruder to be melted at 285°C. The molten polymer was filtered through sintered stainless steel filter media (retaining 95% of particles with a nominal filtration accuracy of 10 μm), formed into sheets from the tube head, and extruded. Then, using an electrostatic casting method, the sheets were wound onto a casting drum with a surface temperature of 30°C, cooled, and cured to produce an unstretched film.

[0192] Next, the coating weight after drying reached 0.12 g / m². 2 In this manner, coating liquid P1 is applied to one side of the unstretched PET film, coating liquid P2 is applied to the opposite side, and then the film is placed in a dryer and dried at 80°C for 20 seconds.

[0193] The unstretched film with the coating layer is fed into a tenter frame. The ends of the film are clamped and introduced into a hot air zone at 135°C, where it is stretched 4.0 times its original width. Then, while maintaining the width obtained from the stretch, the film is treated at 225°C for 30 seconds. Afterward, the ends of the cooled film (to 130°C) are cut with a shear blade at a rate of 0.5 kg / mm². 2 After the edges are trimmed by tension, the film is wound up to obtain a uniaxially oriented PET film A with a thickness of 70 μm. It should be noted that the overall intrinsic viscosity of the film is 0.65 dL / g. The obtained film A is cut into 1300 mm wide pieces, and after knurling both ends, it is wound up with the surface abutting the knurling blade as the outer side, resulting in a roll with a length of 3500 m. The roll is placed in a polyethylene bag, the opening is sealed with rubber, and side plates larger than the outer diameter of the roll are inserted into both ends of the core. It is then stored at 25°C.

[0194] (Manufacturing of Thin Film B)

[0195] Uncoated with P1 coating liquid (coated with P2 coating liquid on one side), with a thickness of 50μm, film B is manufactured in the same manner as film A, and is cut and knurled in the same way to obtain a roll.

[0196] (Knurling)

[0197] Knurling is performed by passing the left and right ends of the cut film between an upper roller that has been knurled and a lower roller that has been mirror-finished. The height of the knurling section is adjusted by adjusting the pressing pressure of the upper roller. The width of the knurling is adjusted by changing the thickness of the lower roller. The knurling blade is heated by induction heating.

[0198] Spacing between the knurling section and the end of the film: 3mm

[0199] Knurling speed: 185m / min

[0200] (Knurling knife)

[0201] The knurling tool is a disc-shaped tool with a thickness of 20mm and a diameter of 100mm. On its outer circumferential surface, it has 10 protrusions arranged at a 45-degree angle along a length of 10mm (10 x 10 protrusions relative to 10mm x 10mm).

[0202] The protruding shape of the knurling tool

[0203] Prismatic A: Base length 1000μm × 1000μm, height 900μm

[0204] Pyramidal type B: Base length 1000μm × 1000μm, height 330μm

[0205] Frustum-shaped pyramid: Grind pyramid A to a height of 600μm.

[0206] Examples 1-11, Comparative Examples 1-7

[0207] The results obtained by using film A and film B and performing knurling under various conditions are shown as examples and comparative examples in Tables 1 and 2. Furthermore, coatings were applied to film A and film B as described below. It should be noted that two films were prepared under the same conditions: one for measuring the knurling height, the pull-out charge, and evaluating the winding state of the roll; the other for evaluating the coating of the coating liquid. It should be noted that the winding tension in Tables 1 and 2 is the tension when the film is wound onto a cylindrical core after knurling at both ends. Additionally, winding is performed while contacting the contact roller; the winding contact pressure is the winding contact pressure of the contact roller at this time.

[0208] The film A is pulled out, and the anti-glare coating liquid with the following composition is applied to the easy-to-adhere layer P2 using a gravure coating machine. After drying in an oven at 90°C, the coating is cured by irradiation with ultraviolet light, thus forming the second anti-glare layer.

[0209] (Composition of the coating liquid for the anti-glare layer)

[0210]

[0211] (Evaluation of coating uniformity of film A)

[0212] The condition of the anti-glare layer from the starting point of the roll of film A to 100m to 150m is observed as an evaluation of the coating uniformity.

[0213] ◎: There is no unevenness in 50m; it is uniform.

[0214] ○: There are several areas within 50m that are considered to be slightly uneven or repulsive.

[0215] △: There are several areas within 50m that are considered to be significantly uneven or repulsive.

[0216] ×: Inhomogeneity or repulsion was frequently observed within 50m.

[0217] The film B is pulled out, and a photoalignment layer coating liquid with the following composition is applied to the surface without the easy-to-adhere layer using a gravure coating machine. After drying at 80°C, a coating film with a thickness of 150 nm is formed. Next, polarized UV light is irradiated, and a photoalignment layer as the second coating layer is laminated to obtain film B. The polarization direction of the UV light is set to 45 degrees relative to the length direction of film B.

[0218] (Coating liquid for photoalignment layer)

[0219] According to Examples 1, 2 and 3 of Japanese Patent Application Publication No. 2013-33248, a 5% by mass solution of the polymer shown in formula (1) in cyclopentanone was prepared.

[0220] 5 parts by mass of the polymer shown in formula (1)

[0221]

[0222] 0.1 parts by weight of surfactant

[0223] 95 parts by weight of cyclopentanone

[0224] (Forming of alignment layers for alignment liquid crystal compounds)

[0225] Next, a coating liquid with the following composition for forming an alignment liquid crystal compound layer is applied to the photoalignment layer using a bar coating method. It is dried at 110°C for 3 minutes and then cured by ultraviolet light to form an alignment liquid crystal compound layer (λ / 4 phase retardation layer) as a second coating layer on the film.

[0226] (Coating solution used to form an aligned liquid crystal compound layer)

[0227]

[0228]

[0229] (Evaluation of coating uniformity of film B)

[0230] The state of the λ / 4 phase difference layer from the starting point of the roll of film B to 100m to 150m was observed. In the observation, a fluorescent lamp-type LED used as a lighting device was installed in the ceiling of an indoor room. Film B, which has a λ / 4 phase difference layer, was placed on an aluminum plate with a mirror-like surface, with the λ / 4 phase difference layer facing down. Then, a polarizing plate was placed above it with the length direction of film B parallel to the extinction axis (absorption axis direction) of the polarizing plate. The uniformity of antireflection of the circular polarizing plate was observed from above as an evaluation of coating uniformity.

[0231] ◎: There is no unevenness within 50m; it is a uniform anti-reflective state.

[0232] ○: There are several areas within 50m where the anti-reflective properties are slightly reduced.

[0233] △: There are several areas within 50m where the anti-reflection performance is significantly reduced.

[0234] ×: Areas with reduced anti-reflective properties frequently exist within 50m.

[0235] [Table 1]

[0236]

[0237] [Table 2]

[0238]

[0239] Industrial availability

[0240] Regarding the elongated strip film of the present invention, the charge carried when the film is pulled out is small up to the core portion. For example, in the case of coating processing of the film, there is little coating repulsion, and a coating with excellent thickness accuracy can be formed up to the end of the film. Furthermore, the elongated resin film of the present invention can suppress winding misalignment and wrinkles after storage and transportation, and the film surface remains undamaged, exhibiting excellent planarity.

Claims

1. A strip-shaped resin film, which is a strip-shaped resin film wound into a roll. The two ends of the film width were knurled. As the observer faces the roll and pulls the film out from the top of the roll towards their face, Set the knurling on the right end to right-side knurling. Set the knurling on the left end to left-side knurling. Set the knurling height of the knurled core on the right side to Hnbr. Set the knurling height of the knurled core on the left side to Hnbl. Set the knurling height of the knurled surface layer on the right side to Hner. When the knurling height of the knurled surface layer on the left is set to Hnel, The following conditions (1), (2) and (3) must be met. (1) Both Hnbr and Hnbl are 0.5–4 μm. (2) The ratios of Hnbr / Hner and Hnbl / Hnel are both 0.3 to 0.

9. (3) The thickness of Hner-Hnbr and Hnel-Hnbl is 0.2-3 μm.

2. The elongated resin film according to claim 1, wherein, Both Hner and Hnel are 1.2–6 μm in size.

3. The elongated resin film according to claim 1, wherein, The absolute value of the uniformity of the knurling height on the left and right sides of the core, calculated by |(Hnbr-Hnbl) / 〔(Hnbr+Hnbl) / 2〕|, is less than 0.

3.

4. The elongated resin film according to any one of claims 1 to 3, wherein, When the outer surface of the long strip resin film is designated as surface A and the inner surface is designated as surface B, the composition of surface A and surface B are different.

5. The elongated resin film according to any one of claims 1 to 3, wherein, When the outer surface of the elongated resin film is designated as surface A and the inner surface is designated as surface B, at least one of surface A and surface B is the surface of the first coating.

6. The elongated resin film according to any one of claims 1 to 3, wherein it is a stretched polyester film.

7. A laminated film comprising an elongated resin film according to any one of claims 1 to 6, and a second coating disposed on at least one side of the elongated resin film.

8. The laminated film according to claim 7, wherein, The second coating may be a hard coating, an anti-glare layer, an anti-reflection layer, a low-reflection layer, an orientation layer, or a phase difference layer.

9. The laminated film according to claim 7 or 8, wherein it is a polarizer protective film or a film for film layer transfer.

10. A method for manufacturing a laminated thin film, comprising: Step (A) of pulling out the elongated resin film according to any one of claims 1 to 6; as well as Step (B) involves applying a second coating liquid to at least one side of an elongated resin film.

11. The method for manufacturing a laminated thin film according to claim 10, wherein, The laminated film is a polarizer protective film.

12. The method for manufacturing a laminated thin film according to claim 10, wherein, The laminated film is a film used for film layer transfer printing.

Images