Film take-up roll

Abstract

This film take-up roll, which is formed by winding an elongated film around a winding core, comprises discontinuous protrusion portions T1, T2, ..., Tn, ... and TN arranged in the longitudinal direction on at least one surface of the film at at least one of the ends in the roll width direction. The protrusion portions are made of a material A different from the film. When the width direction of the film is defined as the x direction, the longitudinal direction is defined as the y direction, the origin of x is defined as the end on one side of the film, the origin of y is defined as the beginning of winding of the film, the coordinates of the center of gravity of Tn are defined as (x, y) = (Xn, Yn), and the average value of the equivalent radius of Tn is defined as r, the difference w between a maximum value and a minimum value of Xn is greater than 2r.

Description

Film winding roll

[0001] The present disclosure relates to a film take-up roll.

[0002] For example, optical films used in displays (display devices) are manufactured in long lengths and distributed as film rolls wound around a core. Films are being manufactured in increasingly wider widths. The wider the width, the more the film roll must be able to withstand the load of the film weight. To increase the load-bearing capacity, it is effective to wind the film around a core with a larger diameter.

[0003] Furthermore, a known conventional film roll is one described in Patent Document 1. Patent Document 1 discloses a film roll including a winding core and a long film wound around the winding core from one end in the longitudinal direction, the film having a long film main body made of a resin and a plurality of protrusions formed on each side of the film main body with a cured resin different from the resin, the protrusions protruding from the film main body, and the plurality of protrusions being provided in an area of ​​at least 2πr in the longitudinal direction of the film in a section of 2% of the film on the one end side, where r is the radius of the winding core.

[0004] Patent Document 1: International Publication No. 2020 / 067321

[0005] An object of one embodiment of the present disclosure is to provide a film winding roll that generates low surface pressure during winding and has excellent suppression of shape deformation due to winding.

[0006] The means for solving the above problems include the following aspects: <1> A film winding roll obtained by winding a long film around a winding core, wherein discontinuous protrusions T are arranged in the longitudinal direction on at least one surface of the film at at least one end in the roll width direction. １ , T ２ , ...T ｎ , ...T ＮThe convex portion is made of a material A different from the film, the width direction of the film is the x direction, the longitudinal direction is the y direction, the origin of x is an end of one side of the film, the origin of y is the start of winding the film, and T ｎ The coordinates of the center of gravity are (x, y) = (X ｎ , Y ｎ ) and T ｎ When the average value of the equivalent radius is r, X ｎ A film winding roll in which the difference w between the maximum and minimum values ​​of is greater than 2r. ｍ And the above T ｍ The closest protrusion T ｍ＋１ The distance d in the x direction between ｘ = | x ｍ -x ｍ＋１ The film winding roll according to <1>, wherein the value of | is greater than 0 and smaller than 0.5r, where m represents an integer of 1 to N-1. ｐ And the above T ｐ The closest protrusion T ｐ＋１ The distance d in the y direction between ｙ = |y ｐ -y ｐ＋１ <4> The film winding roll according to any one of <1> to <3>, wherein the value of | is greater than 2r and smaller than 100r. Here, p represents an integer of 1 to N-1. <5> The film winding roll according to any one of <1> to <3>, wherein the film is wound in an oscillatory manner, and the oscillation width of the oscillatory winding is smaller than 2r. <6> The protrusions T １ , T ２ , ...T ｎ , ...T Ｎ When the total volume of the roll is V and the total length of the roll is L, the value of V / L is 0.02 mm ３ / m to 5mm ３ <6> The film winding roll according to any one of <1> to <4>, wherein the protrusions T １ , T ２ , ...T ｎ , ...T Ｎ When the total volume of the above is V, the value of Y = V / (w + 2r) is 5 mm ２ ~2,000mm ２<7> The film winding roll according to any one of <1> to <5>, wherein the length of the row is l=|y １ -y Ｎ <8> The film winding roll according to any one of <1> to <6>, wherein the value of | is 2πR to 0.5L. Ａ and the Young's modulus Y of the film Ｆ The ratio Y Ａ / Y Ｆ <9> The film winding roll according to any one of <1> to <7>, wherein the Young's modulus Y of the material A is 0.5 or more and 1,000 or less. Ａ and the Young's modulus Y of the film Ｆ The ratio Y Ａ / Y Ｆ The film winding roll according to <8>, wherein the value of y is greater than 1.0 and is equal to or less than 10. <10> The film winding roll according to any one of <1> to <9>, wherein the convex portions are formed at least in a range where y is 0 to 20πR, where R is the radius of the winding core.

[0007] According to one embodiment of the present disclosure, it is possible to provide a film winding roll that generates low surface pressure during winding and has excellent suppression of shape deformation due to winding.

[0008] Fig. 3 is a partially enlarged plan view of a film in a conventional film winding roll. Fig. 4 is a schematic cross-sectional view taken along line aa in Fig. 1. Fig. 5 is a partially enlarged plan view of an example of a film winding roll according to the present disclosure. Fig. 6 is a schematic cross-sectional view taken along line bb in Fig. 3. Fig. 7 is another partially enlarged plan view of an example of a film winding roll according to the present disclosure.

[0009] The present disclosure will be described in detail below. In this specification, the expression "xx to yy" represents a numerical range including xx and yy. In addition, the term "step" in this specification includes not only an independent step, but also a step that cannot be clearly distinguished from other steps, as long as the intended purpose of the step is achieved. In this disclosure, "mass %" and "wt %" are synonymous, and "parts by mass" and "parts by weight" are synonymous. In this disclosure, a combination of two or more preferred aspects is a more preferred aspect.

[0010] (Film Winding Roll) The film winding roll according to the present disclosure is a film winding roll obtained by winding a long film around a winding core, and has discontinuous protrusions T arranged in the longitudinal direction on at least one surface of the film at at least one end in the roll width direction. １ , T ２ , ...T ｎ , ...T Ｎ The convex portion is made of a material A different from the film, the width direction of the film is the x direction, the longitudinal direction is the y direction, the origin of x is an end of one side of the film, the origin of y is the start of winding the film, and T ｎ The coordinates of the center of gravity are (x, y) = (X ｎ , Y ｎ ) and T ｎ When the average value of the equivalent radius is r, X ｎ The difference w between the maximum and minimum values ​​is greater than 2r.

[0011] In conventional film winding rolls, when a film having fine irregularities on its surface is wound into a roll, the surface pressure generated during winding causes damage such as deformation and breakage to the surface irregularities. If the surface pressure is reduced by simply lowering the winding tension to avoid the above, winding slippage and shape deformation due to winding occur. Furthermore, in the method of forming convex portions as described in Patent Document 1, there is a problem in that the convex portions overlap, causing surface pressure to concentrate on the convex portions, resulting in defects such as wrinkles and dents around the convex portions. The film winding roll (also simply referred to as "roll") according to the present disclosure has a row T of discontinuous convex portions aligned in the longitudinal direction on the surface. １ , T ２ , ...T ｎ , ...T Ｎ The protrusions are made of a material A different from the film, the width direction of the roll is the x direction, the longitudinal direction is the y direction, the origin of x is the end of one side of the winding roll, the origin of y is the start of winding, and T ｎ The coordinates of the center of gravity are (x, y) = (X ｎ , Y ｎ ) and T ｎ When the average value of the equivalent radius is r, X ｎIt is estimated that because the difference w between the maximum and minimum values ​​of is greater than 2r, the position of the convex portion fluctuates in the width direction, and the surface pressure does not concentrate during winding, but is dispersed, resulting in low surface pressure during winding and excellent suppression of shape deformation due to winding.

[0012] The film winding roll according to the present disclosure will be described in detail below with reference to the drawings. Note that the description of common components denoted by the same reference numerals in multiple drawings may be omitted.

[0013] FIG. 1 is a partial plan view of a film in a conventional film winding roll. FIG. 1 shows the vicinity of the end of the film 10 in a state where the film 10 is unwound from the film winding roll. MD indicates the longitudinal direction of the film 10. The film 10 shown in FIG. 1 has hemispherical convex portions 12 formed in a line at a fixed position from the end toward the MD. That is, the above-mentioned X ｎ The difference w between the maximum and minimum values ​​of is 0. Figure 2 shows a cross section taken along line a-a in Figure 1, and is an enlarged view of the cross-sectional shape of a conventional film take-up roll. In a conventional film take-up roll, as shown in Figure 2, the convex portions 12 overlap in the same position, and the surface pressure generated during take-up is high in the areas where the convex portions 12 overlap, and the difference TL in cumulative thickness between the areas where the convex portions 12 are present and the areas where they are not present is large, resulting in shape deformation during take-up.

[0014] Fig. 3 is a partially enlarged plan view of an example of a film winding roll according to the present disclosure. Fig. 3 shows the vicinity of the end of the film 10 when the film 10 is unwound from the film winding roll. MD represents the longitudinal direction of the film 10. The film 10 shown in Fig. 3 has hemispherical convex portions 12 formed in a wavy line arrangement with an amplitude greater than 2r near the end. That is, X ｎThe difference w between the maximum and minimum values ​​of is greater than 2r. Figure 4 shows a cross section taken along line b-b in Figure 3, and is an enlarged view of the cross-sectional shape of a conventional film take-up roll. In the film take-up roll according to the present disclosure, as shown in Figure 4, the convex portions 12 overlap at different positions for each lamination, and even if the convex portions 12 are provided, the surface pressure generated during take-up is low, and the difference TL in cumulative thickness between the portion where the convex portions 12 are present and the portion where they are not present is small, thereby suppressing shape deformation due to take-up.

[0015] FIG. 5 is another enlarged plan view of an example of a film winding roll according to the present disclosure, ｎ The difference between the maximum and minimum values ​​of w, a certain convex part T ｍ And the above T ｍ The closest protrusion T ｍ＋１ The distance d in the x direction between ｘ , and the length l of the row of the convex portions 12. The convex portion 12 shown at the bottom of the film 10 in FIG. １ The uppermost convex portion 12 is the convex portion T Ｎ In addition, MD represents the longitudinal direction of the film 10, and TD represents the width direction of the film 10.

[0016] The film take-up roll according to the present disclosure comprises a winding core and a long film. The shape of the winding core is not particularly limited as long as the film can be wound, but is preferably cylindrical or columnar, for example. The film is wound around the winding core from one end in the longitudinal direction into a roll by rotating the winding core in a fixed direction as described below. The film comprises a long film body and a plurality of protrusions protruding from at least one surface of the film body. The protrusions may be formed on either surface of the film, or may be formed on both surfaces. The plurality of protrusions are formed discontinuously in the longitudinal direction and are formed in a partial section of the film in the longitudinal direction.

[0017] <Protrusions> The film winding roll according to the present disclosure has discontinuous protrusions T aligned in the longitudinal direction of the film. １ , T ２ , ...T ｎ , ...T ＮThe convex portion is made of a material A different from the film, the width direction of the film is the x direction, the longitudinal direction is the y direction, the origin of x is an end of one side of the film, the origin of y is the start of winding the film, and T ｎ The coordinates of the center of gravity are (x, y) = (X ｎ , Y ｎ ) and T ｎ When the average value of the equivalent radius is r, X ｎ The difference w between the maximum and minimum values ​​of is greater than 2r. When w is greater than 2r, the difference in level between the convex portion forming portion and other portions is kept small, and wrinkles and dents (depressions) are suppressed when the film is wound up. ｎ The difference w between the maximum and minimum values ​​of X is preferably greater than 2r and less than 30r, more preferably greater than 2r and less than 30r, more preferably greater than 2.2r and less than 20r, and particularly preferably greater than 2.6r and less than 20r, from the viewpoint of the surface pressure generated during winding and the suppression of shape deformation due to winding. ｎ The difference w between the maximum and minimum values ​​of is preferably 0.4 mm to 30 mm, more preferably 0.6 mm to 25 mm, and particularly preferably 0.8 mm to 20 mm, from the viewpoints of the surface pressure generated during winding and the ability to suppress deformation due to winding. Furthermore, when the total width of the film is W, the convex portions are preferably formed in regions at both ends in the width direction of the film, and are preferably present in a region 0.2W from each end in the width direction. The convex portions may be formed in a location other than both ends in the width direction of the film.

[0018] In addition, the protrusion T ｎ The center of gravity of is the center of gravity of the area of ​​the convex portion when the film is observed from the surface direction, and the thickness direction of the film is not taken into consideration.

[0019] The shape of the convex portions is not particularly limited, but is preferably spherical crown-shaped, i.e., has a hemispherical or arch-shaped cross section. This makes it difficult for the tops of the convex portions to be worn away during storage in a film roll in which the film portion is in contact with the apexes of the spherical crown-shaped convex portions, and therefore prevents an increase in the winding surface pressure of the film even after long-term storage. The spherical crown shape does not have to be a strict spherical crown shape, and may be a slightly distorted shape. The shape of the convex portions is not limited to a spherical crown shape, and may be, for example, a cylindrical, polygonal prism, cone, or polygonal pyramid. Furthermore, the shape of the convex portions may be, for example, a convex portion with a flat top. The tops of these convex portions are preferably flat and generally parallel to the film surface. Convex portions with concave tops may also be used.

[0020] The plurality of convex portions may be formed to have roughly the same size as each other, or may be formed to have different sizes. Also, convex portions of different sizes may be arranged with a certain regularity. For example, as shown in FIG. 3, the plurality of convex portions may be arranged in a wavy line shape or a zigzag shape, and X ｎ Any arrangement may be used as long as the difference w between the maximum and minimum values ​​of is greater than 2r. It is also preferable that the size of the multiple protrusions decreases from one end of the film close to the core toward the outside.

[0021] The convex portions may be arranged apart from each other or may be in contact with each other, and may also overlap each other as long as the centers of the convex portions are apart from each other when viewed perpendicularly to the film surface.

[0022] A certain protrusion T ｍ And the above T ｍ The closest protrusion T ｍ＋１ The distance d in the x direction between ｘ = | x ｍ -x ｍ＋１The value of | (unit: mm) is preferably smaller than 0.5r, more preferably greater than 0 and smaller than 0.5r, even more preferably greater than 0 and smaller than 0.3r, and particularly preferably greater than 0 and smaller than 0.1r. Within the above range, the surface pressure applied to the portion where the convex portion is formed is made uniform, suppressing the occurrence of areas where the surface pressure is locally concentrated, thereby suppressing the occurrence of wrinkles and dents due to deformation of the portion where the convex portion is formed. Here, m represents an integer of 1 to N-1.

[0023] A certain protrusion T ｐ And the above T ｐ The closest protrusion T ｐ＋１ The distance d in the y direction between ｙ = |y ｐ -y ｐ＋１ From the viewpoint of the surface pressure generated during winding, the value of | (unit: mm) is preferably greater than 1.5r and less than 150r, more preferably greater than 2r and less than 100r, and particularly preferably greater than 2r and less than 20r. Here, p represents an integer of 1 to N-1.

[0024] In the present disclosure, the protrusions T ｎ The radius of ｎ The shape of the convex portion when viewed from a direction perpendicular to the film surface is circular, but it does not have to be strictly circular. In that case, the equivalent circle diameter (the diameter of a circle when a circle with the same area is assumed) is taken as the above diameter r ｎ In addition, the protrusion T ｎ Radius r ｎ The average value for n = 1 to N is ｎ The average value r of the equivalent radii of the projections T is preferably 0.1 mm or more. When r is 0.1 mm or more, the projections are more effective in retaining the surface pressure during winding, and damage to the film due to the surface pressure can be suppressed. Furthermore, from the viewpoint of the surface pressure generated during winding and the suppression of shape deformation due to winding, r is preferably 0.1 mm to 2.0 mm, more preferably 0.2 mm to 1.5 mm, and particularly preferably 0.3 mm to 1.2 mm. Furthermore, the projections T ｎ The height of hｎ (unit: μm), and the protrusion T ｎ Height h ｎ The average value of h for n = 1 to N is defined as h. From the viewpoint of the surface pressure generated during winding and the ability to suppress deformation due to winding, h is preferably 1 μm to 500 μm. When h is 1 μm or more, the effect of the convex portions to retain the surface pressure during winding is enhanced, and damage to the film due to the surface pressure can be suppressed. When h is 500 μm or less, the occurrence of winding wrinkles caused by excessive concentration of surface pressure on the convex portions can be suppressed. The radius r of the convex portions in the present disclosure ｎ and its average value r, and the height h of the convex portion ｎ The average value h can be measured using a laser microscope (for example, VK-X3000 manufactured by Keyence Corporation).

[0025] The radius r of each protrusion may be constant in the longitudinal direction or may vary. It is also preferable to form the protrusion with a smaller r as it is farther from one end. The height h of each protrusion may be constant in the longitudinal direction or may vary. It is also preferable to form the protrusion with a smaller h as it is farther from one end.

[0026] The convex portions are made of a material A different from the film. From the viewpoints of ease of convex formation and ease of adjusting the Young's modulus, the material A forming the convex portions is preferably a cured resin (polymer) that is a polymerization (crosslinking) product of the cured photocurable compound contained in the photocurable composition described below, and more preferably an ultraviolet-curable resin (UV-curable resin). This cured resin is different from the material constituting the film. The cured resin is a resin produced by a bonding reaction (condensation, addition) to increase the molecular weight through polymerization, crosslinking, etc. The photocurable compound is a compound that cures (including crosslinking) upon irradiation with light, and details will be described later. By forming the convex portions from a cured resin different from the material constituting the film, the convex portions are formed with high strength, and damage to the film surface and wrinkles on the film winding roll are further suppressed. It is more preferable that the cured resin have a structural moiety in which an ethylenically unsaturated group is additionally bonded. In particular, it is even more preferable that the cured resin have a structural moiety in which an acrylamide compound is additionally bonded. It is more preferable that the cured resin have a crosslinked structure in terms of improving the strength of the convex portions and the adhesion between the convex portions and the film body.

[0027] From the viewpoints of ease of forming the convex portions and ease of adjusting the Young's modulus, the convex portions are preferably formed by curing a photocurable composition. The photocurable composition is a composition containing a photocurable compound, and in the present disclosure, it is preferably a liquid mixture containing a liquid photocurable compound. The photocurable compound may be liquid or solid, and if liquid, the photocurable compound may be used alone. Alternatively, a mixture of multiple liquid photocurable compounds may be used as the photocurable composition. The photocurable compound may be any of a monomer, oligomer, or polymer, and is preferably used solvent-free, i.e., without the use of a solvent. Examples of the photocurable compound include compounds having a photocurable ethylenically unsaturated group, such as an acrylic group or a styryl group. The photocurable compound is preferably an ultraviolet-curable compound that cures upon irradiation with ultraviolet light (wavelength in the range of 100 nm to 400 nm). This is because UV-curable compounds require less time to cure than other photo-curable compounds, are easier to form convex portions of the desired shape, and can more reliably reduce damage to the film during the curing process performed by the curing unit described below.

[0028] Examples of the photocurable compound that can be used include polyfunctional acrylate compounds, acrylamide compounds, monofunctional acrylic compounds, etc. Examples of the polyfunctional acrylate compound include (meth)acrylate compounds of polyfunctional alcohols, including alkoxylated polyfunctional (meth)acrylate compounds, and also including oligomers. For example, pentaerythritol tri(meth)acrylate, pentaerythritol tetra(meth)acrylate, dipentaerythritol hexa(meth)acrylate, trimethylolpropane tri(meth)acrylate, 1,6-hexanediol di(meth)acrylate, 1,9-nonanediol di(meth)acrylate, ethylene glycol di(meth)acrylate, diethylene glycol di(meth)acrylate, triethylene glycol di(meth)acrylate, tetraethylene glycol di(meth)acrylate, polyethylene glycol di(meth)acrylate, dipropylene glycol di(meth)acrylate, tripropylene glycol di(meth)acrylate, tetrapropylene glycol di(meth)acrylate, polypropylene glycol di(meth)acrylate, bis(4-acryloxypolyethoxyphenyl)propane, or neopentyl glycol di(meth)acrylate, etc. are preferred. Preferred examples of the alkoxylated polyfunctional (meth)acrylate compound include ethoxylated (3) trimethylolpropane tri(meth)acrylate (a compound obtained by tri(meth)acrylating a trimethylolpropane ethylene oxide 3-mol adduct), propoxylated (3) trimethylolpropane tri(meth)acrylate (a compound obtained by tri(meth)acrylating a trimethylolpropane propylene oxide 3-mol adduct), ethoxylated (2) neopentyl glycol di(meth)acrylate (a compound obtained by diacrylated a neopentyl glycol ethylene oxide 2-mol adduct), and propoxylated (2) neopentyl glycol di(meth)acrylate (a compound obtained by diacrylated a neopentyl glycol propylene oxide 2-mol adduct).

[0029] Preferred examples of the oligomer include polyester (meth)acrylate and urethane (meth)acrylate. Preferred examples of other oligomers include modified glycerin tri(meth)acrylate, modified bisphenol A di(meth)acrylate, propylene oxide (PO) adduct di(meth)acrylate of bisphenol A, ethylene oxide (EO) adduct di(meth)acrylate of bisphenol A, and caprolactone-modified dipentaerythritol hexa(meth)acrylate.

[0030] Preferred acrylamide compounds include hydroxyethylacrylamide, dimethylacrylamide, isopropylacrylamide, diethylacrylamide, dimethylaminopropylacrylamide, N-vinyllactams, specifically N-vinylpyrrolidone, and N-vinylcaprolactam.

[0031] Examples of monofunctional acrylic compounds include isoamyl (meth)acrylate, stearyl (meth)acrylate, lauryl (meth)acrylate, octyl (meth)acrylate, isooctyl (meth)acrylate, decyl (meth)acrylate, isoamylstyl (meth)acrylate, isostearyl (meth)acrylate, 2-ethylhexyl diglycol (meth)acrylate, 2-methoxyethyl (meth)acrylate, butoxyethyl (meth)acrylate, methoxydiethylene glycol (meth)acrylate, methoxypolyethylene glycol (meth)acrylate, methoxypropylene glycol (meth)acrylate, tetrahydrofurfuryl (meth)acrylate, iso Bornyl (meth)acrylate, 2-(meth)acryloyloxyethyl succinate, 2-(meth)acryloyloxyethyl-2-hydroxyethyl phthalate, lactone-modified flexible (meth)acrylate, t-butylcyclohexyl (meth)acrylate, 2-(2-ethoxyethoxy)ethyl (meth)acrylate, cyclopentenyl (meth)acrylate, cyclopentenyloxyethyl (meth)acrylate, dicyclopentanyl (meth)acrylate, 2-hydroxyethyl (meth)acrylate, 2-hydroxypropyl (meth)acrylate, 4-hydroxybutyl (meth)acrylate, or cyclic trimethylolpropane formal (meth)acrylate is preferred. Monofunctional acrylic compounds having a cyclic structure in the molecule are also preferred, and specific examples include acryloylmorpholine, benzyl acrylate, tetrahydrofurfuryl (meth)acrylate, isobornyl (meth)acrylate, cyclopentenyl (meth)acrylate, cyclopentenyloxyethyl (meth)acrylate, dicyclopentanyl (meth)acrylate, cyclic trimethylolpropane formal (meth)acrylate, etc. These monofunctional acrylic compounds having a cyclic structure in the molecule can increase the heat resistance and strength of the convex portions after curing, and suppress foreign matter on the film roll.

[0032] The polyfunctional acrylate compound can improve the hardness and strength of the cured resin product. The acrylamide compound can shorten the time required for curing and form convex portions with improved adhesion to the film. The monofunctional acrylic compound can adjust the physical properties of the photocurable composition.

[0033] The photocurable composition preferably contains an acrylamide compound as the UV-curable compound. The photocurable composition preferably contains an acrylamide compound and a polyfunctional acrylate compound. This allows the ejected droplets to cure rapidly upon irradiation with light, and the cured convex portions have sufficient strength, making it easy to form spherical crown-shaped convex portions, thereby reducing the generation of foreign matter on the film take-up roll. It is also preferable to use two or more polyfunctional acrylate compounds as viscosity modifiers. This allows the viscosity of the photocurable composition to be adjusted within a desired range, and the convex portion shape, for example, height h and radius r, to be adjusted within a desired range. It is also preferable for the photocurable composition to further contain a monofunctional acrylic compound. By uniformly dissolving a photopolymerization initiator or a light stabilizer in the photocurable composition to enhance rapid curing and stability, spherical crown-shaped convex portions can be easily formed, the viscosity can be adjusted within a desired range, and the strength, durability, and heat resistance of the convex portions after curing can be improved, reducing the generation of foreign matter on the film roll.

[0034] The photocurable composition preferably has a viscosity of 5 mPa·s to 1,000 mPa·s. With a viscosity of 5 mPa·s or more, the shape of the droplets is less likely to change between the time they are attached to the film body and the time they are cured by the curing unit. This makes it easier to adjust the timing of curing, and to form convex portions of the desired shape. With a viscosity of 1,000 mPa·s or less, it is easier to adjust the volume of the ejected droplets. This makes it easier to form convex portions of the desired size. The viscosity of the photocurable composition is more preferably 10 mPa·s to 500 mPa·s, and even more preferably 20 mPa·s to 300 mPa·s.

[0035] The viscosity is preferably the viscosity at the ambient temperature during the discharge step described below, but unless otherwise specified, the viscosity is at 25° C. The viscosity in this disclosure is measured using a tuning fork type compact vibration viscometer CJV5000 (A&D Co., Ltd.).

[0036] It is preferable to add a photopolymerization initiator or the like to the photocurable composition in order to shorten the curing time and to increase the strength of the convex portions and the adhesion between the film and the convex portions. Examples of photopolymerization initiators include acetophenones, benzoins, benzophenones, phosphine oxides, ketals, anthraquinones, thioxanthones, azo compounds, peroxides, 2,3-dialkyldione compounds, disulfide compounds, fluoroamine compounds, aromatic sulfonium compounds, lophine dimers, onium salts, borate salts, active esters, active halogens, inorganic complexes, and coumarins. The amount of the photopolymerization initiator is not particularly limited, but is preferably 0.1% by mass to 20% by mass, and more preferably 1% by mass to 15% by mass, relative to the total mass of the photocurable composition.

[0037] Furthermore, it is preferable to add a light stabilizer to enhance the stability of the photocurable composition. Examples of light stabilizers include nitroso-based polymerization inhibitors, hydroquinone, methoxyhydroquinone, benzoquinone, p-methoxyphenol, TEMPO (2,2,6,6-tetramethylpiperidine 1-oxyl), hydroxy-TEMPO (4-hydroxy-2,2,6,6-tetramethylpiperidine 1-oxyl), Al cupferron, and hindered amines. Among these light stabilizers, hindered amine light stabilizers (HALS, Hindered Amine Light Stabilizers) with a secondary or tertiary amine structure are preferred. For example, compounds having a structure in which the 1-position of the nitrogen atom is substituted with an oxy radical (e.g., TEMPO, hydroxy-TEMPO, etc.) are preferred, with 4-hydroxy-TEMPO being particularly preferred.

[0038] The amount of the light stabilizer is preferably 0.05% by mass to 1.0% by mass, and particularly preferably 0.1% by mass to 0.8% by mass, relative to the total mass of the photocurable composition. The photocurable compound can be mixed with other compounds to form a mixed liquid, and the viscosity can be adjusted by adjusting the amount of the polyfunctional acrylate compound, acrylamide compound, or monofunctional acrylic compound. As the viscosity adjuster for adjusting the viscosity, a high-viscosity adjuster that further increases the viscosity and a low-viscosity adjuster that further decreases the viscosity can be used.

[0039] Young's modulus Y of the material A Ａ and the Young's modulus Y of the film Ｆ The ratio Y Ａ / Y Ｆ From the viewpoint of the surface pressure generated during winding and the ability to suppress deformation due to winding, the value of is preferably 0.5 or more and 1,000 or less, more preferably more than 1.0 and 10 or less, even more preferably more than 1.0 and 5.0 or less, and particularly preferably 1.1 or more and 4.0 or less. Ａ is the Young's modulus Y of the film from the viewpoint of the surface pressure generated during winding. Ｆ It is preferable that it is greater than .

[0040] The convex portions may be provided continuously or intermittently in the y direction. The convex portions do not need to be provided over the entire y direction of the film, but may be provided over at least a portion of the y direction. The length l of the row of convex portions is expressed as l=|y where R is the radius of the winding core and L is the total length of the roll. １ -y Ｎ From the viewpoints of the surface pressure generated during winding and the ability to suppress deformation due to winding, the value of | is preferably 2πR to L, more preferably 2πR to 0.5L, and particularly preferably 2πR to 0.1L. Furthermore, from the viewpoints of the surface pressure generated during winding and the ability to suppress deformation due to winding, the value of the length l of the row of convex portions is preferably 0.1m to L, more preferably 0.5m to 0.5L, even more preferably 1m to 200m, and particularly preferably 10m to 100m.

[0041] When the radius of the winding core (the length from the center of the circular cross section of the winding core to the outer periphery) is R (unit: mm), the convex portions are preferably formed in an area of ​​at least 2πr (one circumference of the winding core) in the longitudinal direction of the film, i.e., an area of ​​2πr or more. In this example, the convex portion-forming area is located at one location (one section) in the longitudinal direction of the film, but it may also be located at multiple locations (multiple sections). When convex portions are arranged at multiple locations in the longitudinal direction of the film, it is preferable that the sum of the lengths of all of these convex portion-forming areas (the length in the longitudinal direction of the film) is at least 2πr. When the total length of the film is L (unit: m), the longitudinal length of the area where the convex portions are formed is preferably 2πr to 0.5L, more preferably 4πr to 0.3L, and even more preferably 6πr to 0.2L. Furthermore, from the viewpoint of the surface pressure generated during winding and the ability to suppress deformation due to winding, it is preferable that the convex portion is formed at least in a range where the position y in the y direction at the center of gravity of the convex portion is 0 to 50πR, where R is the radius of the winding core, and it is more preferable that the convex portion is formed at least in a range where y is 0 to 20πR.

[0042] Convex T １ , T ２ , ...T ｎ , ...T Ｎ When the total volume of the roll is V and the total length of the roll is L, the value of V / L is 0.01 mm ３ / m to 10mm ３ / m, and 0.02 mm ３ / m to 5mm ３ / m, and more preferably 0.1 mm ３ / m to 4mm ３ In the above range, the effect of reducing the surface pressure occurring during winding can be sufficiently obtained, and the cumulative thickness caused by overlapping of the convex portions can be reduced, so that the occurrence of wrinkles and winding misalignment can be further suppressed. １ , T ２ , ...T ｎ , ...T Ｎ When the total volume of the above is V, the value of Y = V / (w + 2r) is 2 mm ２ ~3,000mm２ Preferably, it is 5 mm ２ ~2,000mm ２ More preferably, it is 10 mm ２ ~1,500mm ２ More preferably, it is 50 mm ２ ~1,000mm ２ When the thickness is in the above range, the effect of reducing the surface pressure that occurs during winding can be sufficiently obtained, and the cumulative thickness caused by overlapping of the convex portions can be reduced, so that the occurrence of wrinkles and winding misalignment can be further suppressed.

[0043] As described above, when the total length of the film is L (unit: m), multiple protrusions are formed on the film. It is preferable that the multiple protrusions are formed in a region with a length of at least 2πr in the longitudinal direction of the film. In the above-described embodiment, the multiple protrusions on the film wound on one end of the film winding roll maintain the pressure on the film, while the pressure in the widthwise center between both ends (the film portion that will become the product) is kept low. Therefore, damage to the film surface due to pressure is suppressed. The above effect is particularly pronounced when the total length L of the film is at least 200 m, i.e., 200 m or more, and when the film thickness T is thin, ranging from 2 μm to 100 μm. Furthermore, the radius R of the winding core and the width of the film are not particularly limited, but the above effect is particularly pronounced when the radius R of the winding core is within the range of 75 mm to 250 mm and when the film width is within the range of 200 mm to 4000 mm.

[0044] <Film> The film winding roll according to the present disclosure is a film winding roll obtained by winding a long film around a winding core, and has discontinuous protrusions T arranged in the longitudinal direction on at least one surface of the film at at least one end in the roll width direction. １ , T ２ , ...T ｎ , ...T Ｎ and the convex portion is made of a material A different from the film.

[0045] The film is preferably formed from a resin (polymer) or metal that is flexible enough to be wound around a core. For example, when used as an optical film for a display (display device), it is preferably formed from a transparent polymer. In addition to the main material of polymer or metal, the film may contain various additives such as plasticizers, UV absorbers, heat stabilizers, particles, and fibers as composite materials. As a resin material for forming the film, a thermoplastic resin is preferred. There are no particular restrictions on the thermoplastic resin, but preferred examples include polyethylene, polypropylene, polyethylene terephthalate (PET), acrylic resin, polycarbonate, cyclic polyolefin resin, cellulose acylate, acrylic resin, and copolymers thereof. Among these, PET is particularly preferred. There are no particular restrictions on the metal, and known metal foils can be used.

[0046] The total length L (unit: m) of the film is not particularly limited and may be appropriately selected as desired. However, from the viewpoints of ease of handling, the diameter and load-bearing capacity of the film roll, etc., the total length L is preferably from 1 m to 10,000 m, more preferably from 100 m to 5,000 m, and even more preferably from 200 m to 2,000 m.

[0047] The width W (unit: mm) of the film is not particularly limited and may be appropriately selected as desired. However, from the viewpoints of ease of handling, the diameter and load-bearing capacity of the film roll, etc., the width W is preferably 10 mm or more and 10,000 mm or less, more preferably 100 mm or more and 7,000 mm or less, and even more preferably 200 mm or more and 4,000 mm or less.

[0048] The thickness T (unit: μm) of the film is not particularly limited, but is preferably 2 μm or more and 1,000 μm or less, more preferably 5 μm or more and 300 μm or less, and even more preferably 10 μm or more and 200 μm or less, from the viewpoints of handleability, the diameter size and load resistance of the film roll, etc. The thickness T can be determined using a contact-type thickness meter (for example, a film tester thickness meter HK-1200 manufactured by Fujiwork Co., Ltd.).

[0049] In addition to the convex portions, the film may have knurling portions formed on at least one side in the width direction. The knurling portions are preferably formed along the entire length of the film. The formation of the knurling portions prevents slippage between overlapping films during winding, and allows air trapped between the films to escape from the side edges in the width direction, improving the appearance of the film roll and making it less likely to deteriorate even during long-term storage. The term "knurling portion" refers to a knurled portion, which forms concave and convex portions on the surface of the film. In this disclosure, the convex portions and the knurling portion are considered to be different. The knurling portion may be formed such that the concave and convex protrusions protrude from a surface facing the core, or may be formed on the opposite surface facing the outer periphery of the film roll. The size and height (depth) of the concave and convex portions in the knurling portion are not particularly limited and may be selected as appropriate. The method for forming the knurling portion is not particularly limited, and known methods can be used. For example, there is the heat pressing method, in which a metal roll (also called an embossing ring) with a convex shape is pressed against the film while being heated, or the laser method, in which a laser or the like is selectively applied with a wavelength that the film absorbs, thereby heating and deforming the film. In the heat pressing method, the convex and concave shape can be changed by changing the material of the opposing roll (also called a back roll).

[0050] <Winding Core> The film winding roll according to the present disclosure is a film winding roll obtained by winding a long film around a winding core. The material of the winding core is not particularly limited and may be appropriately selected as desired, and known materials may be used. The shape of the winding core is not particularly limited, but is preferably cylindrical or columnar.

[0051] The radius R of the winding core (when the winding core is not cylindrical or columnar, the maximum value of the shortest distance between the rotation axis and the outer surface of the winding core) is not particularly limited and may be selected as desired, but from the viewpoints of handleability, the diameter and load-bearing capacity of the film roll, etc., it is preferably 5 mm to 5,000 mm, more preferably 10 mm to 1,000 mm, and particularly preferably 75 mm to 250 mm. The length (width) of the winding core is not particularly limited and may be selected as appropriate depending on the width of the film, but is preferably 1.0 to 1.5 times the width of the film, and more preferably 1.0 to 1.2 times the width of the film.

[0052] <Oscillating Winding> The film winding roll according to the present disclosure may be either straight wound or oscillating wound. However, from the viewpoint of the surface pressure generated during winding, oscillating winding is preferred. Oscillating winding refers to winding such that the position of the film edge periodically shifts within a certain range (oscillating width) in the width direction of the film each time the film is wound and laminated. Also, winding such that the position of the film edge remains the same in the width direction without shifting is referred to as straight winding. The oscillation width of the oscillating winding is preferably smaller than 2r. Within this range, the effects of the present disclosure can be more effectively exhibited. Furthermore, the oscillation width of the oscillating winding is preferably 10 mm or less, more preferably 5 mm or less, even more preferably greater than 0 mm and 5 mm or less, and particularly preferably 0.5 mm or more and 3 mm or less. Within this range, the effects of the present disclosure can be more effectively exhibited.

[0053] <Method for manufacturing film winding roll> The method for manufacturing a film winding roll according to the present disclosure is not particularly limited, but preferably includes the steps of preparing a film, forming convex portions on the film, and winding the film with the convex portions formed thereon onto a winding core.

[0054] <<Step of Preparing a Film>> The method for manufacturing a film winding roll according to the present disclosure preferably includes a step of preparing a film. The film may be a commercially available product, may be manufactured, or may be a commercially available film that has been processed. Furthermore, the film used may be longer in the longitudinal direction than the film used for one film winding roll. The method for manufacturing the film is not particularly limited, and if the film material is a polymer, any method can be used, such as a method for manufacturing a film by melt extrusion, melt inflation, melt calendering, or solution casting. If the film material is a metal, any method can be used, such as forging, rolling, cutting, or electrolysis.

[0055] <<Step of Forming Convex Portions>> The method for producing a film winding roll according to the present disclosure preferably includes a step of forming convex portions on the film. The method for forming the convex portions is not particularly limited, but is preferably a method in which a photocurable composition is applied by an application unit and cured to form the convex portions, and more preferably a method in which a photocurable composition is discharged by a discharge unit (discharge section) and cured to form the convex portions. The application unit and discharge unit are not particularly limited, and known means can be used.

[0056] In the step of forming the convex portions, it is preferable to apply and cure the photocurable composition while transporting the film. ｙ However, from the viewpoint of reliably forming the convex portions at the desired positions, it is preferable that the speed is 0.1 m / min or more and 500 m / min or less.

[0057] An example of an apparatus used in the step of forming the convex portions will be described below, but it goes without saying that the present invention is not limited to this.

[0058] The discharge unit, which is a discharge means, forms droplets that will become convex portions on a surface of the film. The discharge unit is composed of, for example, a support roller that supports the film and a discharge unit that discharges the photocurable composition as droplets. The support roller, for example, has a film wrapped around its circumferential surface and is a driven roller that rotates when its circumferential surface comes into contact with the film moving in the longitudinal direction. A rotation mechanism may be provided on the support roller, which rotates the rotation shaft. An example of the discharge unit includes two discharge devices that discharge the photocurable composition and, for example, a plate-shaped support member that supports the discharge devices. The number of discharge devices is not particularly limited and can be determined based on the arrangement of the convex portions to be formed. For example, a total of two discharge devices, one on each side, may be used to form a row of convex portions on each side of the film. The discharge device is arranged with its discharge port, which discharges the photocurable composition, facing the circumferential surface of the support roller, which is part of the film transport path. When one of the multiple discharge devices is used, the photocurable composition is intermittently discharged as droplets from a discharge port toward the film being transported, and the droplets are sequentially deposited on the film in the longitudinal direction (discharge step). In this way, the film is produced through the discharge step in the discharge section.

[0059] It is preferable that the photocurable composition is a composition in which droplets of the photocurable composition are deposited on the film and then polymerized by a curing reaction, and the liquid photocurable compound is cured to become integrated with the film body. In the above embodiment, the convex portions can be formed in a spherical crown shape or the like, and further, the height h and diameter r of the convex portions can be adjusted as desired, resulting in the formation of convex portions that have strength and adhesion to the film.

[0060] The curing unit is used to harden the droplets on the film to form convex portions. The curing unit is preferably located downstream of the discharge unit in the film transport direction and includes multiple light sources for irradiating light and, for example, a plate-shaped support member for supporting the multiple light sources. The number of light sources is determined based on the arrangement of the convex portions to be formed, the type of photocurable composition, the film transport speed, etc., and may be one. The wavelength of the light source is determined depending on the photocurable composition used. When an ultraviolet-curable compound is used as the photocurable compound as described above, the light source is preferably one that irradiates ultraviolet light. When irradiated with light from this light source, the photocurable compound contained in the droplets attached to the film body hardens, thereby turning the droplets into convex portions (curing process). In this way, a film with convex portions is obtained. The film with the formed convex portions is moved downstream by rollers and sent to the winding unit.

[0061] The discharge devices each having a discharge unit are preferably arranged in a line in the width direction in the passage area through which each side portion passes. The arrangement of the discharge devices is determined depending on the size of the discharge device and the d of the convex portion to be formed. ｙ It is preferable to determine the shift amount appropriately based on the above factors. It is also preferable to displace the discharge device in the width direction by providing the discharge device so that it can be moved in the width direction and using a shift mechanism that moves the discharge device in the width direction. The shift amount and speed may be determined arbitrarily based on the arrangement of the convex portions. Similarly, it is preferable that the light sources of the curing unit are arranged in a line in the width direction in the passage area through which each side portion passes. It is also preferable that the light sources are respectively arranged at positions in the width direction of the discharge openings of each discharge device. This ensures that light is irradiated onto each droplet formed on the film.

[0062] The droplets on the film change shape as they harden. For example, they may become flattened (become lower in height and larger in radius r), have flattened or concave tops, or other changes in shape. The shape of the convex portions formed by curing depends on the shape of the droplets. To form multiple convex portions with uniform shapes, it is preferable to initiate the curing of the droplets at a consistent timing. To achieve this, the light sources are each positioned at a consistent distance from the discharge port of the discharge device that formed the droplets to be irradiated. This allows irradiation of each droplet to begin a consistent time after formation, resulting in the formation of convex portions with uniform shapes. The number of light sources aligned in the movement direction can be determined appropriately depending on the movement speed of the film body, the viscosity of the photocurable composition, the time required for curing, and other factors.

[0063] As described above, the shape of the convex portions varies depending on the timing at which the droplets on the film begin to harden. This can be utilized to adjust the shape of the convex portions. That is, the shape of the convex portions can be adjusted by adjusting the travel time of the film from the discharge device to the light source. When forming flatter spherical crown-shaped convex portions, when forming convex portions with flat tops, or when forming convex portions with concave tops, it is advisable to increase the travel time from the discharge device to the light source. Furthermore, when forming spherical crown-shaped convex portions with a higher height and a smaller base area, it is advisable to decrease the travel time from the discharge device to the light source.

[0064] The travel time of the film from the ejection device to the light source can be controlled by either changing the film travel speed or by changing the distance between the ejection device and the light source. For example, by shifting the light source upstream in the travel direction, it is possible to form convex portions that are taller and have a smaller base area, and by shifting it downstream, it is possible to form convex portions that are flatter.

[0065] The discharge device preferably includes a case and an opening / closing member. The case preferably includes a case body, a bottom member, a pressing member, an O-ring, a sealing member (packing), etc., and the case is preferably filled with the photocurable composition under pressure. The case body has a supply port for the photocurable composition formed in a side portion, and a supply unit that supplies the photocurable composition at a predetermined flow rate is connected to the supply port.

[0066] The case body preferably has open bottom and top surfaces, with a bottom member fixed to the open portion of the bottom surface and a presser member fixed to the open portion of the top surface. The sealing member is provided on the inner surface of the presser member and, together with an O-ring disposed between the sealing member and the presser member, prevents leakage of the photocurable composition filled inside. The bottom member has a through-hole formed therein, one end of which is exposed to the interior where the photocurable composition is filled, and the other end serves as a discharge port. The diameter (unit: μm) of the discharge port is preferably 10 μm or more and 500 μm or less, and more preferably 20 μm or more and 200 μm or less.

[0067] The opening / closing member is for opening and closing one end of the through hole on the inner side. The opening / closing member is movable between an open position where the one end of the through hole is open and a closed position where the one end is closed. The opening / closing member has an abutment portion, a piezoelectric element, and a driver, and the abutment portion provided at the tip preferably abuts against the bottom member in a state where the one end is closed at the closed position. The abutment portion is preferably fixed via a shaft to the piezoelectric element that deforms when a voltage is applied. The abutment portion moves between the open position and the closed position by increasing or decreasing the voltage applied by the driver. The shaft is inserted through the center of each of the pressing member and the sealing member.

[0068] The photocurable composition is supplied from the supply unit at a predetermined flow rate into the interior of the case, and the supply unit continues to supply the photocurable composition until the interior of the case is filled with the photocurable composition in a pressurized state. The supply unit also supplies the photocurable composition, for example, even when the photocurable composition is discharged from the discharge port, thereby maintaining the pressurized state of the photocurable composition inside. In this way, the supply unit also functions as a pressurizing mechanism.

[0069] By moving the open / close member from the closed position to the open position, the photocurable composition filled under pressure passes through the one end and heads toward the discharge port. Then, by moving the open / close member from the open position to the closed position, a small amount of the photocurable composition in the through-hole is discharged as droplets. The distance between the discharge port and the movement path of the film body is set to a distance greater than the size of the droplets, allowing the droplets to fly through the space. As a result, droplets discharged from the discharge port fly from the discharge port toward the film body and adhere thereto. By moving the open / close member from the closed position to the open position again and then returning it to the closed position, new droplets adhere to a different position in the longitudinal direction of the moving film body. As described above, by repeatedly moving the open / close member from the closed position to the open position, the photocurable composition filled under pressure is discharged as droplets from the discharge port and flies toward the moving film body (discharge process).

[0070] The driver adjusts the period for ejecting each droplet, the flow rate of the photocurable composition supplied to the ejection device, and the volume of the droplet. The volume of the droplet can be adjusted by adjusting the timing of the movement of the opening / closing member. Specifically, the volume of the droplet can be adjusted by adjusting the time it takes for the opening / closing member to move from the closed position to the open position and return to the closed position. The volume of the droplet can also be adjusted by adjusting at least one of the viscosity of the photocurable composition and the pressure of the photocurable composition inside the case.

[0071] Convex part d ｙ is adjusted by adjusting at least one of the cycle at which each droplet is ejected and the moving speed of the film body.

[0072] While the above example illustrates an open-close member equipped with a piezoelectric element, the open-close member is not limited to this example. For example, an open-close member may be used in which a spring-biased contact portion is moved by a change in air pressure instead of a change in the shape of a piezoelectric element. This type of discharge device and discharge mechanism, like the above-described discharge device, are called jet dispensers and jet dispenser systems, and are described in the Journal of the Japan Institute of Electronics Packaging, Vol. 7, No. 6 (page 501), 2004, and commercially available devices can be used. The discharge device and discharge mechanism may also be inkjet-type.

[0073] <<Winding Step>> The method for producing a film winding roll according to the present disclosure preferably includes a step of winding the film having the protrusions formed thereon around a winding core. The protrusion forming step and the winding step may be performed continuously while the film is being transported. In the winding step, a low winding pressure (e.g., winding tension) is preferred from the viewpoint of preventing blocking. The winding tension per unit width in the winding step is preferably 300 N / m or less, more preferably 200 N / m or less, and even more preferably 150 N / m or less. Furthermore, the tension may be gradually reduced as the roll diameter of the film winding roll increases. In the winding step, a winding core may be used, and a cylindrical winding core is preferred. The width of the winding core may be selected appropriately depending on the width of the film. Furthermore, the size (diameter) of the winding core is not particularly limited and may be selected appropriately as desired.

[0074] The film can be wound in the winding step by a method such as straight winding, in which the film is wound around the core so that the edges of the film are aligned, or by oscillating winding, in which the core is periodically vibrated so that the edges of the film are periodically shifted within a certain range in the width direction of the laminate film. The oscillation width may be gradually increased or decreased in the radial direction.

[0075] In addition, the winding step may involve winding while pressing a contact roller against the film. This embodiment effectively removes air trapped between the laminated film during winding, thereby suppressing deformation of the roll after winding. For example, the contact roller may be one described in JP-A-2006-312551. Instead of using a contact roller, air may be blown onto the film to apply pressure. The width of the pressure application is preferably the smooth portion between two uneven portions.

[0076] The method for producing a film winding roll according to the present disclosure may include other known steps in addition to the steps described above, such as a step of knurling the film, a step of surface treating the film, a step of cutting the film, etc.

[0077] Hereinafter, the embodiments of the present disclosure will be described in more detail with reference to examples, but the present disclosure is not limited to the following examples as long as it does not deviate from the gist of the disclosure. Unless otherwise specified, "parts" are based on mass.

[0078] (Examples 1 to 46 and Comparative Examples 1 to 5) Films in Examples 1 to 46 and Comparative Examples 1 to 5 were produced using film production equipment. Films made of polyethylene terephthalate (PET) were produced using a film material production device. The resulting films had a width of 500 mm, a length L of 1,000 m, and a thickness T of 40 μm. Note that L was changed in Examples 45 and 46 as shown in Table 2. The convex portions of each film were formed using the following photocurable composition, as shown in Table 1 or Table 2. The photocurable composition was cured by irradiating ultraviolet light in the following curing unit to form spherical crown-shaped convex portions. Also, an array of wavy convex portions as shown in FIG. 3 was formed. Note that in Example 39, the wavy line shape was changed to a triangular wave shape, and in Example 40, the wavy line shape was changed to a sawtooth wave shape. The height h of the convex portions was 60 μm. The film with the convex portions formed thereon was wound around a winding core (radius 76 mm) to produce each film winding roll. In Examples 43 and 44, the radius R of the winding core was changed as shown in Table 2. In Examples 20 and 21, the films on which convex portions were formed were oscillatorily wound around a winding core (radius 76 mm) at an oscillation width o shown in Table 1 to produce respective film winding rolls.

[0079] The photocurable composition was a mixed solution containing a viscosity increasing agent as a viscosity modifier and a polymerization initiator, and was supplied from a supply unit to a discharge device. Five types of photocurable compositions were prepared, hereinafter referred to as mixed solutions A, B, C, D, and E. Mixed solution A contained 25 parts of dimethylacrylamide (DMAA, manufactured by KJ Chemicals) as the photocurable composition. 71 parts of pentaerythritol triacrylate (PETTA, KAYARAD PET-30, manufactured by Nippon Kayaku Co., Ltd.) was used as the viscosity modifier. The polymerization initiator used was 4 parts of a mixture of Irgacure (registered trademark) 907 (manufactured by BASF Japan Ltd.) and 2,4-diethylthioxanthone (KAYACURE DETX-S, manufactured by Nippon Kayaku Co., Ltd.) in a mass ratio of 1:3. Furthermore, 0.2 parts of 4-hydroxy-2,2,6,6-tetramethylpiperidine 1-oxyl was used as an additive. Mixtures B, C, D, and E were prepared by changing the ratio of the photocurable composition and viscosity modifier in mixture A so that the Young's modulus after curing would be the hardness shown in Table 1 or Table 2.

[0080] The materials of the convex portions and details of the obtained films are shown in Table 1. The droplets of the photocurable composition that form the convex portions are ejected repeatedly at a constant interval, so that the droplets are spaced at equal intervals d in the longitudinal direction. ｙ The convex portions were formed by the above method. The starting position for convex portion formation was the position y=0, at the beginning of winding. A commercially available ultraviolet irradiation device HLUV-126UV365 (manufactured by CCS Inc.) equipped with a light-emitting diode (LED) as a light source was used as the curing unit. The length from the discharge outlet a to the light source was 50 mm. The length range l is the length of the convex portion-forming portion in the longitudinal direction. For each of the obtained films, the convex pattern shape, such as the equivalent radius r of the convex portions and the average height h of the convex portions, was measured by shape analysis using a VK-X3000 laser microscope manufactured by Keyence Corporation. The respective values ​​are shown in Table 1.

[0081] In Comparative Example 2, no photocurable composition was used, and convex portions were formed on the film using a knurling device.

[0082] <Evaluation of maximum surface pressure occurring during winding> The film winding roll was stored for 30 days in an environment with a temperature of 25°C and a relative humidity of 65% RH. After this, the film was unwound from the film winding roll. Both surfaces of the film in the widthwise center of the film portion from the core to 50 m were observed with a microscope (VHX-X1 manufactured by Keyence Corporation) and evaluated using the following indices. A to C are acceptable, and D is unacceptable. A: No defects in the fine irregularities on the surface B: The defects in the fine irregularities on the surface are at most 5% or less of the irregularity height, which is at a level that is acceptable for a product C: The defects in the fine irregularities on the surface are at most more than 5% but not more than 20% of the irregularity height, which is at a level that is acceptable for a product D: The defects in the fine irregularities on the surface are more than 20% of the irregularity height, which is at a level that is problematic for use as a product

[0083] <Evaluation of Shape Deformation Suppression Due to Winding (Evaluation of Wrinkle Formation Suppression)> The film winding roll was stored for 30 days in an environment with a temperature of 25°C and a relative humidity of 65% RH. After this, the film was unwound from the film winding roll. The sides and the vicinity of the sides were visually observed within a range of 100 m from the core of the unwound film, and the degree of deformation was evaluated in the area with the greatest deformation. Specifically, the film was placed on a table covered with a black cloth, and the side and its vicinity were illuminated with light from a fluorescent lamp extending in one direction, and the outline of the fluorescent lamp was visually observed. A and B were acceptable, and C was unacceptable. A: The outline of the fluorescent lamp was observed to be linear and clearly. B: The outline of the fluorescent lamp was distorted and / or unclear, but when it was left for one day and observed again, it was rated as A above. C: The outline of the fluorescent lamp was distorted and / or unclear, so it was left for one day and observed again, but the result was the same.

[0084]

[0085]

[0086] Details of the abbreviations in Tables 1 and 2 are as follows: L: total length of the film in the longitudinal direction (= total length of the roll), R: radius of the winding core, d ｘ : A certain protrusion T ｍ And the above T ｍ The closest protrusion T ｍ＋１ r: distance in the x direction between the protrusion T ｎ The average value of the equivalent radius, d ｙ : A certain protrusion T ｍ And the above T ｍ The closest protrusion T ｍ＋１ y-direction distance between, o: oscillation width, V: convex portion T １ , T ２ , ...T ｎ , ...T Ｎ Y: value of V / (w+2r), l: length of row of convex parts

[0087] As shown in Tables 1 and 2, the film winding rolls of Examples 1 to 46, which are film winding rolls according to the present disclosure, have lower surface pressure during winding and are superior in suppressing shape deformation due to winding, compared to the film winding rolls of Comparative Examples 1 to 5.

[0088] The disclosure of Japanese Patent Application No. 2024-013504, filed on January 31, 2024, is incorporated herein by reference in its entirety. All documents, patent applications, and technical standards mentioned herein are incorporated herein by reference to the same extent as if each individual document, patent application, and technical standard was specifically and individually indicated to be incorporated by reference.

[0089] 10: film, 12: convex portion, MD: longitudinal direction, TD: width direction, TL: difference in cumulative thickness, d ｘ : A certain protrusion T ｍ and the T ｍ The closest protrusion T ｍ＋１ The distance in the x direction between ｎ the difference between the maximum and minimum values ​​of , l: the length of the row of convex parts

Claims

1. A film winding roll in which a long film is wound around a winding core, wherein at least one of the roll width direction ends has discontinuous convex portions T arranged in the longitudinal direction on the surface of at least one of the film. １ , T ２ , ...T ｎ , ...T Ｎ The convex portion is made of a material A different from the film, the width direction of the film is defined as an x direction, the longitudinal direction is defined as a y direction, the origin of x is defined as an end of one side of the film, and the origin of y is defined as a start of winding the film, and T ｎ The coordinates of the center of gravity are (x, y) = (X ｎ , Y ｎ ) and T ｎ When the average value of the equivalent radius is r, X ｎ The difference w between the maximum and minimum values of the film winding roll is greater than 2r.

2. A certain protrusion T ｍ and the T ｍ The closest protrusion T ｍ＋１ The distance d in the x direction between ｘ = | x ｍ -x ｍ＋１ The film take-up roll according to claim 1, wherein the value of | is greater than 0 and smaller than 0.5r, where m represents an integer of 1 to N-1.

3. A certain protrusion T ｐ and the T ｐ The closest protrusion T ｐ＋１ The distance d in the y direction between ｙ = |y ｐ -y ｐ＋１ The film take-up roll according to claim 1 or 2, wherein the value of | is greater than 2r and smaller than 100r, where p represents an integer of 1 to N-1.

4. A film take-up roll according to claim 1 or 2, wherein the film is oscillated and the oscillating width of the oscillating winding is smaller than 2r.

5. Convex T １ , T ２ , ...T ｎ , ...T Ｎ When the total volume of the roll is V and the total length of the roll is L, the value of V / L is 0.02 mm ３ / m to 5mm ３ 3. The film winding roll according to claim 1, wherein the thickness is 1 / m.

6. Convex T １ , T ２ , ...T ｎ , ...T Ｎ When the total volume of the above is V, the value of Y = V / (w + 2r) is 5 mm ２ ~2,000mm ２ The film winding roll according to claim 1 or 2, wherein 7. The radius of the core is R, the total length of the roll is L, and the length of the row is l = |y １ -y Ｎ The film winding roll according to claim 1 or 2, wherein the value of | is 2πR to 0.5L.

8. Young's modulus Y of material A Ａ and the Young's modulus Y of the film Ｆ The ratio Y Ａ / Y Ｆ The film winding roll according to claim 1 or 2, wherein the value of is 0.5 or more and 1,000 or less.

9. Young's modulus Y of material A Ａ and the Young's modulus Y of the film Ｆ The ratio Y Ａ / Y Ｆ The film take-up roll according to claim 8, wherein the value of is greater than 1.0 and is 10 or less.

10. A film winding roll according to claim 1 or 2, wherein the convex portions are formed at least in the range of y=0 to 20πR, where R is the radius of the winding core.

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