Method for manufacturing laminated film with adhesive layer

Abstract

A method for manufacturing a laminated film includes a preparation step and an outer shape processing step. In the preparation step, a long workpiece film (W) [carrier film (C) / film layer (10) / adhesive layer (20) / film layer (30)] is prepared. The adhesive layer (20) has a shear storage modulus of 100 kPa or less at 25 DEG C. In the contour processing step, the workpiece film (W) is irradiated and scanned with laser light (L) from the film layer (30) side, and the film layer (30) to the film layer (10) are fused on the carrier film (C). Thus, a laminated sheet (X) is formed. The laminated sheet (X) is provided with a film (11) having an extended end portion (11A). The spot diameter of the laser light (L) irradiated to the workpiece film (W) on the surface (20b) of the adhesive layer (20) on the film layer (30) side is 200 [mu] m to 500 [mu] m.

Description

Technical Field

[0001] The present invention relates to a method for producing a laminated film having an adhesive layer. Background Art

[0002] The display panel, for example, has a laminated structure including elements such as a pixel panel, a polarizing film, a touch panel, and a protective film. In the manufacturing process of such a display panel, in order to bond the elements contained in the laminated structure to each other, an optically transparent adhesive sheet (optical adhesive sheet) is used, for example. The optical adhesive sheet is manufactured in a form in which both sides of the sheet are covered with a release liner (in the form of a laminated film having an adhesive layer).

[0003] On the other hand, repeatedly bendable (foldable) display panels are being developed, for example for smartphones and tablet terminals. Specifically, foldable display panels are capable of repeatedly deforming between a curved shape and a flat, non-curved shape. In such foldable display panels, each element in the stacked structure is made to be repeatedly bendable, and a thin optical adhesive sheet is used to join such elements. Optical adhesive sheets for flexible devices such as foldable display panels are described, for example, in Patent Document 1 below.

[0004] Prior art literature

[0005] Patent Literature

[0006] Patent Document 1: Japanese Patent Application Publication No. 2018-111754 Summary of the Invention

[0007] Problems to be solved by the invention

[0008] Conventionally, an optical adhesive sheet for a display panel is produced, for example, by the following operation.

[0009] First, if Figure 8A As shown, a workpiece film W' is prepared. Workpiece film W' comprises a long, unprocessed laminate sheet 90 and a long, carrier film C' supporting laminate sheet 90. Laminate sheet 90 has a release liner 91, an adhesive layer 92, and a release liner 93 in this order along the thickness direction H. Release liner 91 is in releasable contact with one surface of adhesive layer 92. Release liner 93 is in releasable contact with the other surface of adhesive layer 92. Carrier film C' supports laminate sheet 90 from the release liner 91 side.

[0010] Then, if Figure 8B As shown, by pressing the laminated sheet 90, a plurality of single-sheet (leaf-shaped) laminated films 90A are formed (pressing process). Figure 9As shown, for the laminated sheet 90, the blade 101 of the knife die (blade type) 100 is pressed into the carrier film C' from the release liner 93 side. As a result, a laminated film 90A of a predetermined top view shape is formed in the laminated sheet 90. The laminated film 90A has a release liner 91A, an adhesive layer 92A, and a release liner 93A in this order in the thickness direction H. In this process, a peripheral portion 90B is formed around the laminated film 90A. In addition, a cut groove 95 ( Figure 8B ).

[0011] Figure 10 An example of a conventional pressing process is shown. Figure 10 In the pressing process shown, the workpiece film W' flowing on the production line passes in sequence between a pair of nip rollers 201, 201, a pressing machine 202, and a pair of nip rollers 203, 203. The pressing machine 202 has an intermittent feeding device, a processing table, and a cutting die arranged above the processing table (all omitted in the figure). The workpiece film W' is relaxed between the pair of nip rollers 201, 201 and the pressing machine 202. The workpiece film W' is relaxed between the pressing machine 202 and the pair of nip rollers 203, 203. The workpiece film W' is intermittently conveyed between the nip rollers 201, 201 and the nip rollers 203, 203 by the intermittent feeding device of the pressing machine 202. As a result, the unprocessed areas of the workpiece film W' are intermittently supplied to the processing table of the pressing machine 202. On the processing table, the cutting die is used to press each unprocessed area of ​​the intermittently supplied workpiece film W'.

[0012] After such a pressing process, Figure 8C As shown, the peripheral portion 90B is removed from the release liner 91 (removal step). Thus, a single-sheet laminated film 90A (release liner 91A / adhesive sheet 92A / release liner 93A) having an adhesive layer is obtained.

[0013] The adhesive sheet (adhesive layer) for flexible devices is required to be highly soft so that it can fully follow the adherend when the device is bent and have excellent stress relaxation properties. Figure 8B ), the release liners 91 and 93 are cut at the same position when viewed from above. That is, the edges of the release liners 91A and 93A formed in the pressing process are aligned when viewed from above. Therefore, in the laminated film 90A, as shown in FIG. Figure 11 As shown, it is easy to form an extended portion 92a of the adhesive sheet 92A (highly soft). The extended portion 92a is a portion of the adhesive sheet 92A that extends outward from the end edges 91e and 93e of the release liners 91A and 93A. The extended portion 92a is formed in the pressing process ( Figure 8B) is attached to the die 100 ( Figure 9 ) and is formed by pulling the cutting die 100.

[0014] When multiple laminated films 90A are stacked in the thickness direction H, the overhanging portion 92a may cause the ends of adjacent laminated films 90A to adhere to each other (end blocking). End blocking reduces the handleability of the laminated films 90A. This problem also occurs when a surface protective film with an adhesive layer is formed on the release liner 91A (the release liner 91A is attached to the adhesive layer side) instead of the adhesive layer 92A and the release liner 93A.

[0015] In addition, in the above-mentioned conventional manufacturing method, the pressing process is performed on each unprocessed area of ​​the workpiece film W' intermittently conveyed to the processing table of the pressing machine 202 ( Figure 8B ). That is, in order to perform the outer shape processing of the laminated film, the workpiece film W' is transported and stopped alternately and repeatedly. To achieve such intermittent transportation, an intermittent transportation device is required, and the device needs to be controlled. Such a conventional manufacturing method is not preferred from the perspective of the manufacturing efficiency of the laminated film having an adhesive layer.

[0016] The present invention provides a method for producing a laminated film suitable for efficiently producing a laminated film having a soft adhesive layer and suitable for suppressing end blocking.

[0017] Means used to solve problems

[0018] The present invention [1] is a method for manufacturing a laminated film, wherein the method for manufacturing a laminated film is a roll-to-roll method for manufacturing a laminated film having an adhesive layer, wherein the method for manufacturing a laminated film comprises: a preparation step, wherein a long workpiece film having a carrier film, a first film layer, an adhesive layer, and a second film layer in sequence in a thickness direction is prepared; a shape processing step, wherein the second film layer, the adhesive layer, and the first film layer are melted and a groove is formed on the carrier film by irradiating and scanning the workpiece film from the second film layer side, thereby forming a shape having the first film layer in sequence in a thickness direction. A laminated film comprising a first film singulated in a layer, an adhesive layer singulated in the adhesive layer, and a second film singulated in the second film layer, wherein the adhesive layer has a shear storage modulus of less than 100 kPa at 25° C., the first film has an extended end portion, and the extended end portion extends further outward than the end edge of the singulated adhesive layer in a surface direction perpendicular to the thickness direction. In the contour processing step, the spot diameter of the laser irradiated on the workpiece film at the surface on the second film layer side in the adhesive layer is greater than 200 μm and less than 500 μm.

[0019] In the contour processing step of the present manufacturing method, as described above, the first film layer, the adhesive layer, and the second film layer on the carrier film are melted by irradiating and scanning the workpiece film with a laser. In the portion where each layer is irradiated with the laser, the material of the layer is evaporated and removed. The soft adhesive layer having a shear storage modulus of 100 kPa or less at 25°C is not an adhesive layer that is cut by pressing the knife die for pressing (the adhesive layer does not adhere to the knife die). Therefore, in the contour processing step, the protruding portion 92a ( Figure 11 This is suitable for suppressing the above-mentioned end blocking in a laminate film having a soft adhesive layer.

[0020] In the contouring process, as described above, the workpiece film is irradiated with a laser from the second film layer side, thereby melting the first film layer, the second film layer, and the adhesive layer on the carrier film. At the portion of the workpiece film where the laser is irradiated, the laser irradiation energy accumulates in the order of the second film layer, the adhesive layer, and the first film layer in the thickness direction, causing each layer to melt due to heating. In the surface direction perpendicular to the thickness direction, the effect of the heating caused by the laser irradiation increases in the order of the first film layer, the adhesive layer, and the second film layer. By such laser irradiation, a groove can be formed that becomes wider the further away from the carrier film. Therefore, in the contouring process, a first film can be formed on the end face (end face facing the groove) of the laminated film (first film, adhesive layer, second film) having an extended end portion extending to the outside of the end edge of the adhesive layer. Specifically, the first film has an outermost end in the surface direction at a position further outward than the outermost end of the adhesive layer. Moreover, as described above, the spot diameter of the laser used in the contouring process on the surface of the second film layer side of the adhesive layer is relatively large, which is greater than 200μm. This is suitable for forming a first film having a significantly long protruding end portion. A laminated film in which the first film has such a protruding end portion is suitable for suppressing the above-mentioned end portion blocking.

[0021] As described above, the laser spot diameter at the surface of the adhesive layer on the second film side used in the contour processing step is 500 μm or less. This configuration is suitable for reducing the exposed area of ​​the adhesive layer on the second film side at the end of the laminated film facing the cutout (the width increases as it moves away from the carrier film). Therefore, this configuration is suitable for suppressing the aforementioned end blocking when the laminated films are stacked in the thickness direction.

[0022] Furthermore, in the contouring step, as described above, the laminated film having an adhesive layer is contoured by laser processing. Laser processing is suitable for continuous contouring while allowing the workpiece film to flow continuously (no need to intermittently transport the workpiece film for contouring). Therefore, this production method is suitable for efficiently producing laminated films having an adhesive layer.

[0023] As described above, the present production method is suitable for efficiently producing a laminated film having a soft adhesive layer and suppressing edge blocking.

[0024] The present invention [2] includes the method for producing a laminated film having an adhesive layer according to the above [1], wherein the cut groove is formed by a single pass of processing using the laser.

[0025] Forming the grooves by machining the workpiece film in one pass is suitable for shortening the unit process time in manufacturing the laminated film, and is therefore suitable for efficiently manufacturing the laminated film.

[0026] The present invention [3] includes the method for producing a laminated film having an adhesive layer according to [1] or [2] above, wherein the laser is a CO2 laser.

[0027] CO2 laser is suitable for melting the first film layer, the second film layer and the adhesive layer with different materials and optical properties (absorbance, etc.) at one time.

[0028] The present invention [4] includes a method for manufacturing a laminated film having an adhesive layer as described in any one of [1] to [3] above, wherein, in the outer shape processing step, the carrier film side of the workpiece film is attracted by a processing table capable of adsorbing the workpiece film while the workpiece film is slid along the length direction on the processing table, and the workpiece film is irradiated and scanned with the laser from the second film layer side.

[0029] Such a configuration is preferable for accurately aligning the focus of the laser light on the workpiece film continuously flowing on the production line in the outer shape processing step, and is therefore preferable for laser processing the workpiece film efficiently and accurately.

[0030] The present invention [5] includes a method for manufacturing a laminated film having an adhesive layer as described in any one of [1] to [4] above, wherein the first cut groove and the second cut groove extending in a direction intersecting the longitudinal direction of the workpiece film are formed adjacent to each other in the longitudinal direction, and the spacing distance between the adhesive layers adjacent to each other in the longitudinal direction separated by the first cut groove and the second cut groove is less than 2 mm.

[0031] Such a configuration is preferable for achieving high productivity of the laminated film.

[0032] The present invention [6] comprises the method for producing a laminated film having an adhesive layer according to any one of [1] to [5], wherein the laser is a Gaussian laser.

[0033] Gaussian lasers are suitable for forming grooves that become wider as they get farther from the carrier film during the contour processing step. Therefore, Gaussian lasers are suitable for forming the first film with a significantly long protruding end portion. BRIEF DESCRIPTION OF THE DRAWINGS

[0034] Figure 1 The following describes the steps of one embodiment of the method for producing a laminated film having an adhesive layer according to the present invention. Figure 1 A represents the preparation process, Figure 1 B represents the shape processing process, Figure 1 C represents a removal step.

[0035] Figure 2 For the shape processing process in the workpiece film ( Figure 1 B) Schematic top view of an example of the subsequent region.

[0036] Figure 3 It is a partially enlarged cross-sectional view of a laminated film produced by the method for producing a laminated film having an adhesive layer of the present invention.

[0037] Figure 4 A three-dimensional diagram showing the shape processing process.

[0038] Figure 5 A cross-sectional view showing the shape processing process.

[0039] Figure 6 Schematic diagram of the internal structure of the laser processing unit.

[0040] Figure 7 A perspective view of an example of a galvanometer scanner.

[0041] FIG. 8 shows an example of a conventional method for producing a laminated film having an adhesive layer. Figure 8A Indicates the preparation process, Figure 8B Indicates the pressing process. Figure 8C Indicates the removal process.

[0042] Figure 9 Indicates the pressing process using a die.

[0043] Figure 10 An example of a conventional pressing process is shown.

[0044] Figure 11 This is an enlarged cross-sectional view of a conventional laminated film having a soft adhesive layer after a pressing step. DETAILED DESCRIPTION

[0045] The method for producing a laminated film as one embodiment of the present invention is a roll-to-roll method for producing a sheet-shaped laminated film having an adhesive layer. Figure 1 A to Figure 1 As shown in C, this manufacturing method includes a preparation step ( Figure 1 A) Shape processing Figure 1 B) and removal process ( Figure 1 C).

[0046] In the preparation process, such as Figure 1 As shown in A, a long workpiece film W is prepared. The workpiece film W includes a laminate sheet X and a carrier film C. The laminate sheet X is a laminate film Y ( Figure 1 The carrier film C supports the laminated sheet X.

[0047] The laminate sheet X comprises a film layer 10 (first film layer), an adhesive layer 20, and a film layer 30 (second film layer) in this order along the thickness direction H. The adhesive layer 20 has a first surface 20a and a second surface 20b opposite the first surface 20a. The film layer 10 is in contact with the first surface 20a. The film layer 30 is in contact with the second surface 20b. The laminate sheet X extends in a plane direction perpendicular to the thickness direction H.

[0048] The carrier film C is a single-sided adhesive film having an adhesive surface on one side in the thickness direction H. In the workpiece film W, the adhesive surface of the carrier film C is attached to the film layer 10 side of the laminate sheet X. Specifically, the workpiece film W includes the carrier film C, the film layer 10, the adhesive layer 20, and the film layer 30 in this order in the thickness direction H.

[0049] In addition, in this embodiment, the carrier film C is perpendicular to the flow direction D1 of the workpiece film W in the width direction D2 ( Figure 2 ) is wider than the laminate sheet X. The laminate sheet X is, for example, arranged at the center of the width direction D2 on the carrier film C. The width (length in the width direction D2) of the laminate sheet X is, for example, 200 mm or greater, preferably 280 mm or greater, more preferably 400 mm or greater, and, for example, 2000 mm or less, preferably 1800 mm or less, more preferably 1600 mm or less. Such a workpiece film W flows on the production line.

[0050] In this embodiment, the film layer 10 is a release liner. Examples of materials for the release liner include polyester, polyolefin, and polycarbonate. Examples of polyester include polyethylene terephthalate, polyethylene naphthalate, and polybutylene terephthalate. Examples of polyolefin include polyethylene, polypropylene, and cycloolefin polymer (COP). The film layer 10 serving as a release liner is in releasable contact with the first surface 20a of the adhesive layer 20. The surface of such a film layer 10 (the surface on the adhesive layer 20 side) is preferably subjected to a release treatment. Examples of release treatments include silicone release treatment and fluorine-containing release treatment. From the perspective of ensuring the protective function of the adhesive layer 20, the thickness of the film layer 10 is preferably 10 μm or more, more preferably 15 μm or more, and further preferably 20 μm or more. From the perspective of thinning the laminated film Y, the thickness of the film layer 10 is preferably 150 μm or less, more preferably 120 μm or less, and further preferably 100 μm or less.

[0051] The adhesive layer 20 is formed from an adhesive composition. The adhesive composition includes a base polymer. The base polymer is an adhesive component that exhibits adhesive properties. Examples of the base polymer include acrylic polymers, polyurethane polymers, polyamide polymers, and polyvinyl ether polymers. The base polymers may be used alone or in combination of two or more. From the perspective of ensuring good transparency and adhesive properties of the adhesive layer 20, an acrylic polymer is preferably used as the base polymer.

[0052] Acrylic polymers are polymers containing 50% or more by mass of a (meth)acrylate monomer component. "(Meth)acrylic acid" refers to acrylic acid and / or methacrylic acid. Alkyl (meth)acrylates are preferably used as (meth)acrylates, and more preferably, those in which the alkyl group has 1 to 20 carbon atoms.

[0053] Examples of the alkyl (meth)acrylate include methyl (meth)acrylate, ethyl (meth)acrylate, n-butyl (meth)acrylate, pentyl (meth)acrylate, n-hexyl (meth)acrylate, heptyl (meth)acrylate, 2-ethylhexyl (meth)acrylate, n-octyl (meth)acrylate, isooctyl (meth)acrylate, nonyl (meth)acrylate, isononyl (meth)acrylate, decyl (meth)acrylate, isodecyl (meth)acrylate, undecyl (meth)acrylate, dodecyl (meth)acrylate (i.e., lauryl (meth)acrylate), isotridecyl (meth)acrylate, and tetradecyl (meth)acrylate. The alkyl (meth)acrylate may be used alone or in combination of two or more. The alkyl (meth)acrylate is preferably at least one selected from the group consisting of 2-ethylhexyl acrylate (2EHA), lauryl acrylate (LA), and n-butyl acrylate (BA). From the viewpoint of appropriately expressing basic properties such as adhesiveness in the adhesive layer 20, the proportion of the (meth)acrylate in the monomer component is preferably 60% by mass or more, more preferably 70% by mass or more, further preferably 90% by mass or more, and for example, 99% by mass or less.

[0054] The monomer component may include a copolymerizable monomer capable of copolymerizing with the alkyl (meth)acrylate. Examples of copolymerizable monomers include monomers having polar groups. Examples of polar group-containing monomers include hydroxyl group-containing monomers, monomers having a nitrogen atom-containing ring, and carboxyl group-containing monomers. Polar group-containing monomers contribute to the modification of acrylic polymers by introducing crosslinking points into the acrylic polymer and ensuring the cohesive strength of the acrylic polymer.

[0055] As hydroxyl-containing monomers, for example, 2-hydroxyethyl (meth)acrylate, 2-hydroxypropyl (meth)acrylate, and 4-hydroxybutyl (meth)acrylate can be cited. As hydroxyl-containing monomers, it is preferred to use at least one selected from the group consisting of 2-hydroxyethyl acrylate (2HEA) and 4-hydroxybutyl acrylate (4HBA). From the viewpoint of introducing a cross-linked structure into the acrylic polymer and ensuring the cohesive force of the adhesive layer 20, the proportion of hydroxyl-containing monomers in the monomer component is preferably 1% by mass or more, more preferably 2% by mass or more, and further preferably 3% by mass or more. From the viewpoint of adjusting the polarity of the acrylic polymer, the proportion is preferably 20% by mass or less, more preferably 10% by mass or less. The polarity of the acrylic polymer is related to the compatibility of the acrylic polymer in the adhesive layer 20 with the various additive components.

[0056] As the monomer with nitrogen-containing atom ring, for example, N-vinyl-2-pyrrolidone, N-methylvinylpyrrolidone, N-vinylpyridine, N-vinylpiperidone, N-vinylpyrimidine, N-vinylpiperazine, N-vinylpyrrole, N-vinylimidazole, N-(methyl)acryloyl-2-pyrrolidone and acryloylmorpholine can be cited. As the monomer with nitrogen-containing atom ring, N-vinyl-2-pyrrolidone (NVP) is preferably used. From the viewpoint of ensuring the cohesive force of the adhesive layer 20 and ensuring the adhesion of the adhesive layer 20 to the adherend, the ratio of the monomer with nitrogen-containing atom ring in the monomer component is preferably 0.1% by mass or more, more preferably 0.5% by mass or more, and further preferably 1% by mass or more. From the viewpoint of regulating the glass transition temperature of the acrylic polymer and regulating the polarity of the acrylic polymer, the ratio is preferably 10% by mass or less, more preferably 5% by mass or less, and further preferably 3% by mass or less.

[0057] The base polymer preferably has a cross-linked structure. As a method for introducing a cross-linked structure into the base polymer, for example, the following first method and second method can be cited. In the first method, a base polymer and a cross-linking agent having a functional group capable of reacting with a cross-linking agent are combined in the adhesive composition, and the base polymer and the cross-linking agent are reacted in the adhesive sheet. In the second method, a polyfunctional compound as a cross-linking agent is included in the monomer component forming the base polymer, and a base polymer having a branched structure (cross-linked structure) introduced into the polymer chain is formed through polymerization of the monomer component. These methods can also be used in combination.

[0058] Examples of the crosslinking agent used in the first method include compounds that react with functional groups (hydroxyl groups, carboxyl groups, etc.) contained in the base polymer. Examples of such crosslinking agents include isocyanate crosslinking agents, peroxide crosslinking agents, and epoxy crosslinking agents. The crosslinking agents may be used alone or in combination of two or more.

[0059] In the second method described above, the monomer components (including the multifunctional monomer and other monomers for introducing a cross-linking structure) can be polymerized at one time or in multiple steps. In the multi-step polymerization method, first, the monofunctional monomer for forming the base polymer is polymerized (prepolymerization) to prepare a prepolymer composition containing a partial polymer (a mixture of a polymer with a low degree of polymerization and unreacted monomers). Next, a multifunctional monomer as a cross-linking agent is added to the prepolymer composition, and then the partial polymer and the multifunctional monomer are polymerized (main polymerization). As a multifunctional monomer, for example, a multifunctional (meth)acrylate containing two or more ethylenically unsaturated double bonds in one molecule can be listed. As a multifunctional monomer, from the viewpoint of being able to introduce a cross-linking structure by active energy ray polymerization (photopolymerization), a multifunctional acrylate is preferred. As a multifunctional (meth)acrylate, for example, dipentaerythritol hexaacrylate (DPHA), ethylene glycol di(meth)acrylate, 1,6-hexanediol di(meth)acrylate, trimethylolpropane tri(meth)acrylate can be listed.

[0060] Acrylic polymers can be formed by polymerizing the aforementioned monomer components. Examples of polymerization methods include solution polymerization, solvent-free photopolymerization (e.g., UV polymerization), bulk polymerization, and emulsion polymerization. Examples of solvents for solution polymerization include ethyl acetate and toluene. Examples of polymerization initiators include thermal polymerization initiators and photopolymerization initiators.

[0061] From the perspective of ensuring the cohesive force of the adhesive layer 20, the weight average molecular weight of the base polymer is preferably 100,000 or more, more preferably 300,000 or more, and even more preferably 500,000 or more. The weight average molecular weight is preferably 5,000,000 or less, more preferably 3,000,000 or less, and even more preferably 2,000,000 or less. The weight average molecular weight of the base polymer is measured by gel permeation chromatography (GPC) and calculated by polystyrene conversion.

[0062] The glass transition temperature (Tg) of the base polymer can be calculated based on the following Fox equation (theoretical value). The Fox equation is the product of the glass transition temperature Tg of the polymer and the glass transition temperature Tg of the homopolymer of the monomer constituting the polymer. iIn the following Fox equation, Tg represents the glass transition temperature (°C) of the polymer, Wi represents the weight fraction of monomer i constituting the polymer, and Tgi represents the glass transition temperature (°C) of the homopolymer formed by monomer i. Regarding the glass transition temperature of the homopolymer, literature values ​​can be used. For example, the glass transition temperatures of various homopolymers in the "Polymer Handbook" (4th edition, John Wiley & Sons, Inc., 1999) can be listed. On the other hand, the glass transition temperature of the homopolymer of a monomer can be calculated by the method specifically described in Japanese Patent Application Laid-Open No. 2007-51271.

[0063] Fox formula 1 / (273+Tg)=Σ[Wi / (273+Tgi)]

[0064] From the viewpoint of ensuring the flexibility of the adhesive layer 20 , the base polymer preferably has a glass transition temperature (Tg) of 0° C. or lower, more preferably -10° C. or lower, and even more preferably -20° C. or lower. For example, the glass transition temperature is -80° C. or higher.

[0065] The adhesive composition may contain other components as needed. Examples of other components include solvents, silane coupling agents, ultraviolet absorbers, tackifiers, softeners, and antioxidants.

[0066] The haze of the adhesive layer 20 is preferably 3% or less, more preferably 2% or less, and even more preferably 1% or less. The haze of the adhesive layer 20 can be measured using a haze meter in accordance with JIS K7136 (2000). Examples of haze meters include the "NDH2000" manufactured by Nippon Denshoku Industries and the "HM-150" manufactured by Murakami Color Research Laboratory.

[0067] From the perspective of ensuring the cohesive force of the adhesive layer 20, the shear storage modulus of the adhesive layer 20 at 25°C is preferably 10 kPa or more, more preferably 15 kPa or more, further preferably 20 kPa or more, and particularly preferably 25 kPa or more. From the perspective of achieving the flexibility required for an optical adhesive sheet for flexible device applications in the adhesive layer 20, the shear storage modulus of the adhesive layer 20 at 25°C is 100 kPa or less, preferably 80 kPa or less, more preferably 70 kPa or less, further preferably 60 kPa or less, and particularly preferably 50 kPa or less. As a method for adjusting the shear storage modulus, for example, the selection of the type of base polymer in the adhesive layer 20, the adjustment of the molecular weight, the adjustment of the blending amount, the adjustment of the glass transition temperature, and the adjustment of the degree of crosslinking can be listed. As a method for adjusting the shear storage modulus, the selection of components other than the base polymer in the adhesive layer 20 and the adjustment of the blending amount can also be listed. The shear storage modulus of the adhesive layer is obtained by dynamic viscoelasticity measurement. This measurement can be performed using the Advanced Rheological Swelling System (ARES), a dynamic viscoelasticity measuring device manufactured by Rheometric Scientific. The measurement mode is set to shear mode, the measurement temperature range is set to -40°C to 100°C, the heating rate is set to 5°C / minute, and the frequency is set to 1 Hz.

[0068] The film layer 30 is, for example, a release liner, a surface protection film, a functional optical film, or a base film (support film).

[0069] As the material of the release liner, for example, polyester, polyolefin and polycarbonate can be cited. Specifically, the materials of the release liner mentioned above for the film layer 10 can be cited. The film layer 30 serving as the release liner is in releasable contact with the second surface 20b of the adhesive layer 20. The surface of such a film layer 30 (the surface on the adhesive layer 20 side) is preferably subjected to a release treatment. As the release treatment, for example, polysiloxane release treatment and fluorine-containing release treatment can be cited. From the viewpoint of ensuring the protective function of the adhesive layer 20, the thickness of the film layer 30 serving as the release liner is preferably 10 μm or more, more preferably 15 μm or more, and further preferably 20 μm or more. From the viewpoint of thinning the laminated film Y, the thickness of the film layer 30 serving as the release liner is preferably 150 μm or less, more preferably 120 μm or less, and further preferably 100 μm or less.

[0070] When the film layer 30 is a surface protection film, the second surface 20b of the adhesive layer 20 is bonded to the film layer 30. The film layer 30 as a surface protection film and the adhesive layer 20 form a surface protection film with an adhesive layer.

[0071] As materials for the surface protective film, for example, polyimide (PI), polyester, polyolefin and polycarbonate can be listed. As polyester, for example, polyethylene terephthalate, polyethylene naphthalate and polybutylene terephthalate can be listed. As polyolefin, for example, polyethylene, polypropylene and cycloolefin polymer (COP) can be listed. From the viewpoint of ensuring the protective function as a surface protective film, the thickness of the film layer 30 as a surface protective film is preferably 10 μm or more, more preferably 15 μm or more, and further preferably 20 μm or more. From the viewpoint of thinning the surface protective film with an adhesive layer, the thickness of the film layer 30 as a surface protective film is preferably 100 μm or less, more preferably 70 μm or less, and further preferably 50 μm or less.

[0072] Examples of functional optical films include polarizing films and phase difference films. Functional optical films may also be other optical films, such as panel reinforcement materials. When the film layer 30 is a functional optical film, the second surface 20b of the adhesive layer 20 is bonded to the film layer 30. The film layer 30, which is a functional optical film, and the adhesive layer 20 form a functional optical film with an adhesive layer.

[0073] As polarizing films, for example, hydrophilic polymer films that have been dyed with a dichroic substance and subsequently stretched are listed. As dichroic substances, for example, iodine and dichroic dyes are listed. As hydrophilic polymer films, for example, polyvinyl alcohol (PVA) films, partially formalized PVA films, and partially saponified films of ethylene-vinyl acetate copolymers are listed. As polarizing films, polyene oriented films are also listed. As materials for polyene oriented films, for example, dehydrated products of PVA and dehydrochlorinated products of polyvinyl chloride are listed. The polarizing film may have a protective film bonded to one surface and / or the other surface in the thickness direction via an adhesive. From the viewpoint of ensuring the function, strength, and durability of the polarizing film, the thickness of the polarizing film is preferably 10 μm or more, more preferably 20 μm or more. From the viewpoint of thinning the laminated film Y, the thickness of the polarizing film is preferably 500 μm or less, more preferably 300 μm or less.

[0074] As phase difference films, for example, λ / 2 wavelength films, λ / 4 wavelength films and viewing angle compensation films can be listed. As materials for phase difference films, for example, polymer films that have been birefringent by stretching treatment can be listed. As polymer films, for example, cellulose films and polyester films can be listed. As cellulose films, for example, triacetyl cellulose films can be listed. As polyester films, for example, polyethylene terephthalate films, polyethylene naphthalate films and polybutylene terephthalate films can be listed. As phase difference films, there can also be listed: films having a substrate such as a cellulose film and an orientation layer on the substrate. The orientation layer is formed of a liquid crystal compound such as a liquid crystal polymer. From the viewpoint of ensuring the function and strength of the phase difference film, the thickness of the phase difference film is preferably 1 μm or more, more preferably 2 μm or more. From the viewpoint of thinning the laminated film Y, the thickness of the phase difference film is preferably 100 μm or less, more preferably 80 μm or less.

[0075] As the material of the substrate film, for example, the materials described above as the material of the release liner can be cited. In the case where the film layer 30 is a substrate film, the second surface 20b of the adhesive layer 20 is bonded to such a film layer 30. The film layer 30 as a substrate film and the adhesive layer 20 form a single-sided adhesive sheet. From the viewpoint of ensuring the strength as a substrate, the thickness of the substrate film is preferably 10 μm or more, more preferably 20 μm or more, and further preferably 30 μm or more. From the viewpoint of thinning the laminated film Y, the thickness of the substrate film is preferably 200 μm or less, more preferably 150 μm or less, and further preferably 100 μm or less.

[0076] The laminated sheet X can be manufactured, for example, as follows. First, the above-mentioned adhesive composition is applied to the film layer 30 to form a coating film. Then, the film layer 10 is attached to the coating film on the film layer 30. Then, the coating film between the film layers 10 and 30 is dried, and the coating film is irradiated with light as needed. Thus, the adhesive layer 20 is formed between the film layers 10 and 30. Examples of the coating method of the adhesive composition include roller coating, contact roller coating, gravure coating, and die coating. The drying temperature of the coating film is, for example, 50°C to 200°C. The drying time is, for example, 5 seconds to 20 minutes.

[0077] In the shape processing process, such as Figure 1As shown in B, by laser processing the workpiece film W, a monolithic laminated film Y is formed in the laminated sheet X. Specifically, a laser processing device is used to irradiate and scan the workpiece film W with a laser L from the film layer 30 side, thereby melting the film layer 30, the adhesive layer 20 and the film layer 10 on the carrier film C to form a groove G. The spot diameter S of the laser L irradiated on the workpiece film W at the surface 20b of the adhesive layer 20 (the surface on the film layer 30 side) is greater than 200 μm and less than 500 μm. The groove G is formed in a manner that advances along the predetermined processing line (designed cutting line) of the workpiece film W. The groove G has a depth in the thickness direction H. The groove G has a shape in which the groove width becomes wider as it is away from the carrier film C. In this process, a monolithic film 31 is formed in the film layer 30. A monolithic adhesive layer 21 is formed in the adhesive layer 20. A monolithic film 11 is formed in the film layer 10. The film layers 11 and 31 and the adhesive layer 21 form a laminated film Y. Around the laminated film Y, a peripheral portion Xa is formed. Figure 2 FIG. 1 is a top view schematically showing an example of a region after the outer shape processing step in the workpiece film W. Figure 2 In the figure, the groove G is indicated by a shadow. Figure 1 The partial cross-sectional view shown in B is equivalent to Figure 2 A partial cross-sectional view of the workpiece film W along line II is shown.

[0078] like Figure 3 As shown, the laminated film Y has a film 11, an adhesive layer 21, and a film 31 in this order in the thickness direction H. The film 11 has an end face 11a facing the groove G. The adhesive layer 21 has an end face 21a facing the groove G. The end face 21a is flush with the end face 11a. The film 31 has an end face 31a facing the groove G. The end face 31a is flush with the end face 21a. The end faces 11a, 21a, 31a are formed as inclined surfaces that are inclined in a manner that expands outward toward the carrier film C in the thickness direction H, or are formed as curved surfaces that are curved in a manner that expands outward toward the carrier film C in the thickness direction H (in the embodiment of FIG. 1 ). Figure 3 , the tilted case is shown by way of example). Angle α formed between end face 11a and the surface of film 11 on the carrier film C side (the tilted angle of end face 11a) is, for example, 20° to 80°. Angle β formed between end face 21a and the surface of adhesive layer 21 on the film 11 side (the tilted angle of end face 21a) is, for example, greater than angle α and in the range of 40° to 80°. Angle γ formed between end face 31a and the surface of film 31 on the adhesive layer 21 side (the tilted angle of end face 31a) is, for example, the same as angle α and in the range of 20° to 80°.

[0079] The film 11 has an extended end portion 11A. The extended end portion 11A extends further outward than the end face 21a of the adhesive layer 21 in the surface direction D orthogonal to the thickness direction H. That is, the film 11 has an outer end 11e at a position further outward than the outer end 21e of the adhesive layer 21 in the surface direction D. From the viewpoint of suppressing the above-mentioned end adhesion in the laminated film Y, the extended length d1 of the extended end portion 11A from the end face 21a in the surface direction D (the direction orthogonal to the end face 21a when viewed from above) is preferably 70 μm or more, more preferably 90 μm or more, and further preferably 100 μm or more. From the viewpoint of efficient manufacturing of the laminated film Y, the extended length d1 is preferably 200 μm or less, more preferably 170 μm or less, and further preferably 150 μm or less. The extended length d1 is the length from the outer end 21e of the adhesive layer 21 to the outer end 11e of the film 11 in the surface direction D, and is the maximum length of the extended end portion 11A.

[0080] In the films 11 and 31 exposed in the cutout G, the distance between the outer end 11e of the film 11 and the inner end 31e of the film 31 in the plane direction D is defined as the edge width d2 ( Figure 3 As shown). That is, the edge width d2 is the maximum length in the surface direction D from the outer end 11e of the film 11 to the inner end 31e of the film 31. The edge width d2 is preferably 600 μm or less, more preferably 550 μm or less. The edge width d2 is, for example, 100 μm or more or 200 μm or more. The area of ​​the edge width d2 is a part of the edge area that can be used as an alignment mark (edge ​​alignment mark) for end detection of the manufactured laminated film Y. When the edge width d2 is 600 μm or less (preferably 550 μm or less), it is possible to suppress erroneous detection of the edge alignment mark by the detection camera (when the edge alignment mark is too large, erroneous detection occurs).

[0081] Between the laminated films Y adjacent to each other in the flow direction D1 (longitudinal direction) of the workpiece film W, a slit G (first slit) and another slit G (second slit) extending in a direction intersecting the flow direction D1 (longitudinal direction) are formed adjacent to each other in the flow direction D1. The adhesive layers 21 adjacent to each other in the flow direction D1 are separated by a distance d3 ( Figure 1 B) is preferably 2 mm or less, more preferably 1.7 mm or less, and even more preferably 1.5 mm or less. This configuration is preferred for achieving high productivity of the laminated film Y. Separation distance d3 is, for example, 0.5 mm or more, 0.7 mm or more, or 1.0 mm or more. Separation distance d3 of less than 2 mm cannot be achieved in press processing using a die cutter. Separation distance d3 is the shortest length between adjacent adhesive layers 21 in the flow direction D1.

[0082] Examples of lasers used for laser processing include gas lasers, solid-state lasers, and semiconductor lasers. Examples of gas lasers include excimer lasers and CO2 lasers. Examples of excimer lasers include F2 excimer lasers (157 nm), ArF excimer lasers (193 nm), KrF excimer lasers (248 nm), and XeCl excimer lasers (308 nm) (the numerical values ​​in parentheses indicate the laser wavelengths. The same shall apply to lasers). Examples of solid-state lasers include Nd:YAG lasers (1064 nm), the second harmonic of Nd:YAG lasers (532 nm), the third harmonic of Nd:YAG lasers (355 nm), and the fourth harmonic of Nd:YAG lasers (266 nm). Examples of semiconductor lasers include semiconductor lasers with a wavelength of 405 nm. As a process for the outer shape processing ( Figure 1 The laser L in B) is preferably a CO2 laser from the viewpoint of simultaneously cutting the film layers 10 and 30 having different materials and optical properties (absorbance, etc.) and the adhesive layer 20. A CO2 laser is also preferred from the viewpoint of easily increasing the spot diameter S of the laser L.

[0083] The spot diameter S of the laser light L at the surface 20 b of the adhesive layer 20 can be adjusted, for example, by defocusing the laser light L. During defocusing, the focal position of the laser light L is moved up and down relative to the surface 20 b in the thickness direction H. The farther the focal position of the laser light L is from the surface 20 b, the larger the spot diameter S at the surface 20 b.

[0084] Laser L is preferably a Gaussian laser. A Gaussian laser has a Gaussian energy intensity distribution. This laser is ideal for forming a groove G that becomes wider as it moves away from the carrier film C. Therefore, a Gaussian laser is ideal for forming a film 11 having a significantly longer protruding end portion 11A.

[0085] The cut groove G is preferably formed by a single laser pass. Forming the cut groove G by performing a single pass of processing on the workpiece film W is suitable for reducing the unit time in the manufacture of the laminated film Y, and is therefore suitable for efficiently manufacturing the laminated film Y. In this embodiment, the single pass processing means that the cut groove G is dug out by a single scan of the laser irradiation point.

[0086] The output power of the laser light L is, for example, 2 W to 500 W. The frequency of the pulse of the laser light L is, for example, 10 kHz to 30 kHz.

[0087] In this embodiment, as the outer shape processing step ( Figure 1 B) laser processing device, using Figure 4 and Figure 5 The laser processing device 100 is shown.

[0088] In this embodiment, the laser processing apparatus 100 includes a processing table 110 , a laser processing unit 120 , and a control unit (not shown).

[0089] The processing table 110 is a table that supports the workpiece film W flowing in the production line. Figure 5 As shown, the processing table 110 has a support table 111 and a suction path 112. The support table 111 forms a support surface for the workpiece film W on the processing table 110. The support table 111 has a plurality of suction holes 111a that penetrate the support table 111 in the thickness direction H. The suction path 112 is a space formed in the processing table 110. The suction path 112 is located below the support table 111. The suction holes 111a of the support table 111 are connected to the suction path 112. The suction path 112 is connected to the suction path of a pressure reducing pump (not shown). The pressure reducing pump is operated to reduce the pressure in the suction path 112. The pressure reducing pump can select an operating state and a non-operating state according to the control of the control unit. When there is a workpiece film W on the support table 111, the workpiece film W is sucked to the support table 111 of the processing table 110 by reducing the pressure in the suction path 112.

[0090] like Figure 4 As shown, a pair of clamping rollers N1 and N1 are arranged on the upstream side of the production line of the processing table 110. In a state where the workpiece film W is clamped by a pair of clamping rollers N1 and N1, each clamping roller N1 is rotated at a certain speed, thereby stretching the workpiece film W and conveying it to the processing table 110. On the other hand, a pair of clamping rollers N2 and N2 are arranged on the downstream side of the production line of the processing table 110. In a state where the workpiece film W is clamped by a pair of clamping rollers N2 and N2, each clamping roller N2 is rotated at a certain speed, thereby stretching the workpiece film W and conveying it to the downstream side of the clamping rollers N2 and N2. Through the clamping rollers N1 and N1 and the clamping rollers N2 and N2, the workpiece film W flows on the support table 111 of the processing table 110 along the length direction (flow direction D1) of the film. By adjusting the suction path 112 ( Figure 5 ) is decompressed, and the workpiece film W is attracted to the processing table 110 while sliding on the processing table 110. This is preferable for precisely aligning the focus of the laser light L with the workpiece film W continuously flowing on the production line during the contour processing step, and is therefore preferable for efficiently and accurately laser processing the workpiece film W.

[0091] like Figure 6As schematically shown in FIG, the laser processing unit 120 includes a housing 121, a laser light source 122, a beam expander 123, a movable lens 124, a condenser lens 125, and a galvanometer scanner Sc. The laser light source 122, the beam expander 123, the movable lens 124, the condenser lens 125, and the galvanometer scanner Sc are housed in the housing 121. The housing 121 has a laser emission port (not shown).

[0092] The laser light source 122 oscillates and emits laser light L. As the laser light source, a CO 2 laser light source is preferably used from the viewpoint of appropriately cutting a plurality of layers having different materials and optical characteristics (absorbance, etc.).

[0093] The beam expander 123 is an optical component that adjusts the beam size of the laser light L. Other optical components may be arranged between the beam expander 123 and the movable lens 124. Examples of the other optical components include a collimator lens and a homogenizer.

[0094] The movable lens 124 is a lens that can be displaced in the optical axis direction of the laser light L. By displacing the movable lens 124 in the optical axis direction, the position of the focal point of the laser light L focused by the condenser lens 125 (the position of the focal point on the workpiece film W) changes. The position of the movable lens 124 in the optical axis direction can be adjusted under the control of the control unit (position control of the movable lens 124).

[0095] The laser light L that has passed through the condenser lens 125 is reflected by the galvanometer scanner Sc. Figure 6 and Figure 7 As shown, the galvanometer scanner Sc has a galvanometer mirror 126 (first galvanometer mirror), a galvanometer motor 127 (first galvanometer motor), a galvanometer mirror 128 (second galvanometer mirror), and a galvanometer motor 129 (second galvanometer motor).

[0096] The galvanometer mirror 126 has a mirror surface 126a capable of reflecting the laser light L. The galvanometer motor 127 has a motor shaft core 127a connected to the galvanometer mirror 126. The motor shaft core 127a extends in a first direction. The first direction is preferably a direction orthogonal to the flow direction D1 and the width direction D2 of the workpiece film W. The galvanometer motor 127 can swing the direction (first mirror surface direction) of the mirror surface 126a of the galvanometer mirror 126 around a rotation axis extending along the motor shaft core 127a. The galvanometer motor 127 can control the first mirror surface direction in the galvanometer mirror 126 according to the control of the control unit.

[0097] The galvanometer mirror 128 has a mirror surface 128a capable of reflecting the laser light L. The galvanometer motor 129 has a motor shaft core 129a connected to the galvanometer mirror 128. The motor shaft core 129a extends in a second direction. The second direction intersects with the first direction. The second direction is preferably orthogonal to the first direction. The second direction is preferably the width direction D2. The galvanometer motor 129 can swing the direction (second mirror surface direction) of the mirror surface 128a of the galvanometer mirror 128 around a rotation axis extending along the motor shaft core 129a. The galvanometer motor 129 can control the second mirror surface direction in the galvanometer mirror 128 according to the control of the control unit.

[0098] In the galvanometer scanner Sc, the laser light L is sequentially reflected by the mirror surface 126a of the galvanometer mirror 126 and the mirror surface 128a of the galvanometer mirror 128. The laser light L passes through the laser emission port of the housing 121 and is irradiated onto the workpiece film W on the processing table 110.

[0099] In the laser processing unit 120, the laser light L is scanned across the workpiece film W by controlling the first and second mirror directions of the galvanometer motors 127 and 129. Specifically, the laser light L from the laser processing unit 120 is scanned along the flow direction D1 and the surface direction D2 by controlling the first and second mirror directions of the galvanometer motors 127 and 129, so that the irradiation spot on the workpiece film W travels along the intended processing line of the workpiece film W. In the laser processing unit 120, the laser light L is scanned within a predetermined range (scanning area) centered substantially directly below the galvanometer scanner Sc. Furthermore, the position of the movable lens 124 is controlled by the first and second mirror directions so that the size of the irradiation spot remains the same regardless of changes in the incident angle of the scanning laser light L with respect to the workpiece film W (the angle between the normal to the surface of the film and the optical axis of the laser light L). In addition, during the scanning of the laser L, the galvanometer scanner Sc (galvanometer motors 127, 129) is controlled by the control unit so that the position of the irradiation spot determined by the composite speed (vector) of the transport speed (vector) of the workpiece film W and the scanning speed (vector) of the laser L moves along the predetermined processing line in the workpiece film W.

[0100] The laser processing unit 120 may include a telecentric fθ lens at a position after the laser light L passes through the galvanometer scanner Sc. This fθ lens helps ensure that the spot diameter S of the laser light L remains the same regardless of changes in the incident angle of the laser light L with respect to the workpiece film W. If the laser processing unit 120 includes such an fθ lens, the movable lens 124 may not be required. If a telecentric fθ lens having a diameter larger than the width (the length in the width direction D2) of the scanning area allocated to the laser processing unit 120 can be used, such an fθ lens is preferably used. Furthermore, the laser processing unit 120 may use a telecentric fθ lens and the movable lens 124 described above in combination.

[0101] In this manufacturing method, in the outer shape processing step ( Figure 1 B) Afterwards, if Figure 1 As shown in C, the peripheral portion Xa is removed from the carrier film C (removal step).

[0102] By the above operation, it is possible to produce a laminated film Y (laminated film having an adhesive layer). After the film 31 is peeled off from the adhesive layer 21 , another film may be bonded to the adhesive layer 21 .

[0103] In the shape processing step ( Figure 1 B), as described above, the film layer 10, the adhesive layer 20, and the film layer 30 on the carrier film C are melted by irradiating and scanning the workpiece film W with the laser L. In the portion where the laser L is irradiated on each layer, the material of the layer is evaporated and removed. The soft adhesive layer 20 having a shear storage modulus of 100 kPa or less at 25°C is not an adhesive layer that is cut by pressing the die for pressing (the adhesive layer 20 does not adhere to the die). Therefore, in the contour processing step, the protruding portion 92a ( Figure 11 This is suitable for suppressing the above-mentioned end blocking in the laminated film Y having the soft adhesive layer 21.

[0104] During the contouring process, as described above, the workpiece film W is irradiated with laser light L from the film layer 30 side, causing the film layers 10, 30 and the adhesive layer 20 on the carrier film C to melt. At the portion of the workpiece film W irradiated with laser light L, the irradiation energy of laser light L accumulates in the thickness direction H in the order of film layer 30, adhesive layer 20, and film layer 10, causing each layer to melt due to heating. In the surface direction D perpendicular to the thickness direction H, the heating effect caused by the irradiation of laser light L increases in the order of film layer 10, adhesive layer 20, and film layer 30. This laser irradiation allows the formation of a groove G that becomes wider the further away from the carrier film C. Therefore, during the contouring process, a film 11 can be formed having an extended end portion 11A extending outward from the end face 21a of the adhesive layer 21 on the end face of the laminated film Y (the end face facing the groove G). Furthermore, as described above, the spot diameter S of the laser light L used in the outer shape processing step at the surface 20 b (the surface on the film layer 30 side) of the adhesive layer 20 is relatively large, not less than 200 μm.

[0105] This is suitable for forming a film 11 having a significantly long overhanging end portion 11A. A laminated film Y having such an overhanging end portion 11A is suitable for suppressing the aforementioned end blocking. From the perspective of increasing the overhanging length d1 of the overhanging end portion 11A, the spot diameter S is preferably 230 μm or greater, more preferably 250 μm or greater, and even more preferably 270 μm or greater.

[0106] As described above, the spot diameter S of the laser L used in the contour processing step at the surface 20b of the adhesive layer 20 is 500 μm or less. Such a structure is suitable for reducing the exposed area of ​​the adhesive layer 21 on the film 30 side at the end of the laminated film Y facing the cut groove G (the farther away from the carrier film C, the wider the width). Therefore, this structure is suitable for suppressing the above-mentioned end adhesion when the laminated film Y is stacked in the thickness direction. In addition, the spot diameter S of 500 μm or less is suitable for suppressing the edge width d2 from becoming too large, and thus, it is possible to suppress the erroneous detection of the edge alignment mark caused by the detection camera. From the viewpoint of suppressing end adhesion and the viewpoint of suppressing erroneous detection of the edge alignment mark, the spot diameter S is preferably 470 μm or less, and more preferably 400 μm or less.

[0107] Furthermore, in the contouring step, as described above, the laminate film Y (laminated film having an adhesive layer) is contoured by laser processing. Laser processing is suitable for continuous contouring while allowing the workpiece film W to flow continuously (there is no need to intermittently transport the workpiece film W for contouring). Therefore, this manufacturing method is suitable for efficiently manufacturing the laminate film Y.

[0108] As described above, the present production method is suitable for efficiently producing a laminated film Y having a soft adhesive layer 21 and suppressing end blocking.

[0109] Example

[0110] The present invention is described in detail below with reference to the following examples. However, the present invention is not limited to the examples. In addition, the specific numerical values ​​of the following amounts (contents), physical property values, parameters, etc. can be replaced with the upper limits (defined as "below" or "less than") or lower limits (defined as "above" or "greater than") of the amounts (contents), physical property values, parameters, etc. corresponding to these amounts (contents), physical property values, parameters, etc. described in the above-mentioned "Specific Embodiments".

[0111] [Example 1]

[0112] A laminated film having an adhesive layer was produced as follows.

[0113] <Preparation of Adhesive Composition>

[0114] First, a mixture containing 50 parts by mass of 2-ethylhexyl acrylate (2EHA), 40 parts by mass of lauryl acrylate (LA), 2 parts by mass of n-butyl acrylate (BA), 6 parts by mass of 4-hydroxybutyl acrylate (4HBA), 2 parts by mass of N-vinyl-2-pyrrolidone (NVP), and 0.015 parts by mass of a photopolymerization initiator (product name "Omnirad 184" manufactured by IGM Resins) was irradiated with ultraviolet light (polymerization reaction) to obtain a prepolymer composition (polymerization rate of approximately 10%) (the prepolymer composition contains monomer components that have not undergone polymerization reaction). Next, 100 parts by mass of the prepolymer composition, 0.08 parts by mass of dipentaerythritol hexaacrylate (DPHA) as a multifunctional acrylate monomer, and 0.3 parts by mass of a silane coupling agent (product name "KBM-403" 3-glycidoxypropyltrimethoxysilane, manufactured by Shin-Etsu Chemical Co., Ltd.) were mixed to obtain an adhesive composition.

[0115] <Production of Release Liner>

[0116] First, 90 parts by mass of a polysiloxane release agent (product name "KE-3703," a 28.5% toluene solution of an addition-type silicone release agent containing a polysiloxane having a hexenyl group in the molecule and a polyorganosiloxane crosslinker having a hydrosilyl group in the molecule, manufactured by Shin-Etsu Chemical Co., Ltd.), 0.9 parts by mass of a silicone release control agent (product name "KS-3800," manufactured by Shin-Etsu Chemical Co., Ltd.), and 0.3 parts by mass of a platinum catalyst for silicone curing (product name "CAT-PL-50T," manufactured by Shin-Etsu Chemical Co., Ltd.) were mixed with a solvent to prepare a release agent solution with a silicone solids concentration of 0.7% by mass. The solvent was a mixed solvent of toluene and hexane at a volume ratio of 1:1. Next, a release treatment was performed on a biaxially stretched polyester film (product name "Lumirror XD500P," 50 μm thick, manufactured by Toray Advanced Materials Co., Ltd.). Specifically, the aforementioned release agent solution was first applied to one side of the polyester film to form a coating. This coating was performed using a wire rod #9. The coating was then dried by heating the film at 130°C for 1 minute in a hot air dryer. This formed a 0.1 μm thick silicone release layer (release treatment) on the polyester film. This procedure produced a release liner with a release treatment on one side.

[0117] <Production of workpiece film>

[0118] First, an adhesive composition is applied to the release-treated surface of the release liner to form a coating. Then, the plasma-treated surface of a surface protective film that has been plasma-treated on one side is attached to the coating on the release liner. The surface protective film is a specific polyethylene terephthalate (PET) film with a thickness of 50 μm. In the plasma treatment, a plasma irradiation device (product name "AP-TO5", manufactured by Sekisui Industries) is used, the voltage is set to 160 V, the frequency is set to 10 kHz, and the processing speed is set to 5000 mm / minute. Then, the coating is irradiated with ultraviolet rays from the surface protective film side to cure the coating, thereby forming an adhesive layer with a thickness of 25 μm. A laminated sheet (release liner / adhesive layer / surface protective film) as a raw material of a laminated film with an adhesive layer is thus obtained. In the ultraviolet irradiation, a black light lamp is used as the irradiation light source, and the irradiation intensity is set to 5 mW / cm 2 Then, a carrier film was attached to the laminated sheet. The carrier film is a single-sided adhesive film having an adhesive surface on one side in the thickness direction. The adhesive surface of the carrier film was attached to the release liner side of the laminated sheet.

[0119] By the above operation, a workpiece film was prepared. The workpiece film had a carrier film, a release liner (first film layer), an adhesive layer, and a surface protection film (second film layer) in this order in the thickness direction.

[0120] <Outer shape processing>

[0121] Next, the workpiece film is laser processed to shape the release liner, adhesive layer and surface protective film on the carrier film. Specifically, by irradiating and scanning the workpiece film with a laser from the surface protective film side, the surface protective film, adhesive layer and release liner are melted in a manner that moves along the predetermined cutting line in the laminated sheet to form a cut groove. In this process, a laser processing device (product name "LC500", manufactured by Takei Electric Industry) is used, a CO2 laser with a wavelength of 9360nm is used as the laser, the laser spot diameter S is set to 258μm, the laser output power is set to 20W, the pulse frequency is set to 30kHz, the laser cutting speed is set to 500mm / second, and the number of scans (passes) is set to 1. The spot diameter S refers to the spot diameter at the surface of the surface protective film side in the adhesive layer (the same applies to the embodiments and comparative examples described later). Through this process, a single-piece laminated film and a peripheral portion around the laminated film are formed on the carrier film. The laminate film comprises a release liner (first film), an adhesive layer, and a surface protective film (second film) in this order in the thickness direction. The release liner has an extended end portion extending outward from the end edge of the adhesive layer in the surface direction. Furthermore, after the contour processing step, the peripheral portion is removed from the carrier film.

[0122] The laminated film of Example 1 (laminated film having an adhesive layer) was produced in the above-described manner.

[0123] [Example 2]

[0124] A laminated film of Example 2 was produced in the same manner as in Example 1 except for the following matters: In the outer shape processing step, a CO2 laser with a wavelength of 10250 nm was used as the laser instead of the CO2 laser with a wavelength of 9360 nm, and the spot diameter S was set to 230 μm.

[0125] [Example 3]

[0126] A laminated film of Example 3 was produced in the same manner as in Example 1, except that the spot diameter S was set to 353 μm in the outer shape processing step.

[0127] [Example 4]

[0128] A laminated film of Example 4 was produced in the same manner as in Example 1, except that the spot diameter S was set to 462 μm in the outer shape processing step.

[0129] [Comparative Example 1]

[0130] A laminated film of Comparative Example 1 was produced in the same manner as in Example 1, except that the spot diameter S was set to 100 μm in the outer shape processing step.

[0131] [Comparative Example 2]

[0132] A laminated film of Comparative Example 2 was produced in the same manner as in Example 1 except for the following matters: In the outer shape processing step, a CO2 laser with a wavelength of 10250 nm was used as the laser instead of the CO2 laser with a wavelength of 9360 nm, and the spot diameter S was set to 100 μm.

[0133] [Comparative Example 3]

[0134] A laminated film of Comparative Example 3 was produced in the same manner as in Example 1 except that the spot diameter S was set to 155 μm in the outer shape processing step.

[0135] [Comparative Example 4]

[0136] A laminated film of Comparative Example 4 was produced in the same manner as in Example 1, except that the spot diameter S was set to 572 μm in the outer shape processing step.

[0137] [Comparative Example 5]

[0138] A laminated film of Comparative Example 5 was produced in the same manner as in Example 1, except that the spot diameter S was set to 1130 μm in the outer shape processing step.

[0139] <Shear storage modulus>

[0140] The dynamic viscoelasticity of the pressure-sensitive adhesive layers in Examples and Comparative Examples was measured.

[0141] First, a plurality of adhesive layer sheets cut out from an adhesive layer were bonded together to produce a sample sheet having a thickness of approximately 1.5 mm. This sheet was then punched out to obtain cylindrical pellets (7.9 mm in diameter) as measurement samples.

[0142] Then, for the sample for measurement, a dynamic viscoelasticity measuring apparatus (product name "Advanced Rheological Expansion System (ARES)", manufactured by Rheometric Scientific) was used to fix the sample for measurement to a fixture of a parallel plate with a diameter of 7.9 mm and perform dynamic viscoelasticity measurement. In this measurement, the measurement mode was set to shear mode, the measurement temperature range was set to -40°C to 100°C, the heating rate was set to 5°C / min, and the frequency was set to 1 Hz. The shear storage modulus at 25°C was read from the measurement results. Its values ​​are shown in Table 1.

[0143] <Shape Analysis>

[0144] The shapes of the laminated films produced in Examples 1 to 4 and Comparative Examples 1 to 5 were analyzed using a shape analysis laser microscope (product name "VK-X1000", manufactured by KEYENCE). Specifically, the extended length d1 ( Figure 3 ) and edge width d2( Figure 3 The results are shown in Table 1. Regarding the suppression of misalignment, a margin width d2 of 600 μm or less was evaluated as "acceptable," while a margin width d2 greater than 600 μm was evaluated as "unacceptable." The evaluation results are shown in Table 1.

[0145] <Suppression of End Blocking>

[0146] For each laminated film of Examples 1 to 4 and Comparative Examples 1 to 5, the difficulty of the occurrence of end blocking was investigated. Specifically, first, for each laminated film, 10 evaluation samples of substantially the same size were made, and the 10 evaluation samples were stacked to form a film bundle (first process). In the film bundle, in the thickness direction, the ends of the 10 laminated films are substantially flush and connected. Next, the front end adhesive surface of a cylindrical rod (diameter 10 mm) having an adhesive surface at the front end was pressed against the laminated film located at the top in the film bundle from above, and then the rod was lifted upward, and the number of laminated films lifted along with the rod was counted (second process). Ten tests consisting of the first process and the subsequent second process were performed on each film bundle. Then, the suppression of end blocking was evaluated as follows. In the 10 tests, the case where the number of tests in which only one laminated film was lifted along with the rod was 10 was evaluated as "excellent", the case where the number was 6 to 9 was evaluated as "qualified", and the case where it was 5 or less was evaluated as "unqualified". Table 1 shows the evaluation results.

[0147] <Suppression of Protrusion of Adhesive Layer>

[0148] For each laminated film of Examples 1 to 4 and Comparative Examples 1 to 5, the non-protrusion property of the adhesive layer was studied. Specifically, first, for each laminated film, 10 evaluation samples of substantially the same size were made, and the 10 evaluation samples were stacked to form a film bundle. In the film bundle, the ends of the 10 laminated films are substantially flush with each other in the thickness direction. Next, the end face of the film bundle was touched with a finger to check whether the end face felt sticky. Then, the suppression of the protrusion of the adhesive layer in the laminated film was evaluated as follows. The case where no stickiness was felt at all on the end face was evaluated as "qualified", and the case where stickiness was felt on the end face was evaluated as "unqualified". The evaluation results are shown in Table 1.

[0149]

[0150]

[0151] The above embodiments are merely illustrative of the present invention and should not be construed as limiting the present invention. Modifications of the present invention that are obvious to those skilled in the art are intended to fall within the scope of the claims.

[0152] Industrial Applicability

[0153] The method for producing a laminated film having an adhesive layer of the present invention can be applied to a method for producing a laminated film (having an adhesive layer) as a feed material for an optical adhesive sheet for a foldable display panel, for example.

[0154] Label Description

[0155] W workpiece film

[0156] X-Laminated Sheets

[0157] Y laminated film

[0158] C carrier membrane

[0159] H thickness direction

[0160] D-plane direction

[0161] D1 flow direction

[0162] D2 width direction

[0163] 10 film layers (first film layer)

[0164] 11 membranes

[0165] 11A extended end

[0166] 20, 21 adhesive layer

[0167] 20b surface

[0168] 30 film layers (second film layer)

[0169] 31 membranes

[0170] L Laser

[0171] 100 laser processing equipment

[0172] 110 processing table

[0173] 111 support platform

[0174] 111a suction hole

[0175] 112 Attraction Path

[0176] 120 laser processing unit

[0177] Sc galvanometer scanner

Claims

1. A method for producing a laminated film, wherein the method is a roll-to-roll method for producing a laminated film having an adhesive layer, wherein: The method for manufacturing the laminated film comprises: A preparation step, wherein a long workpiece film having a carrier film, a first film layer, an adhesive layer, and a second film layer in sequence in a thickness direction is prepared; a contour processing step, wherein the second film layer, the adhesive layer, and the first film layer are melted and cut into grooves on the carrier film by irradiating and scanning the workpiece film from the second film layer side, thereby forming a laminated film having, in the thickness direction, the first film singulated in the first film layer, the adhesive layer singulated in the adhesive layer, and the second film singulated in the second film layer; The adhesive layer has a shear storage modulus of 100 kPa or less at 25° C., The first film has an extended end portion that extends outward from an edge of the individualized adhesive layer in a plane direction perpendicular to the thickness direction. In the outer shape processing step, a spot diameter of the laser light irradiated on the workpiece film at a surface of the adhesive layer on the second film layer side is 200 μm or more and 500 μm or less.

2. The method for producing a laminated film having an adhesive layer according to claim 1, wherein The cut groove is formed by a single pass of machining using the laser.

3. The method for producing a laminated film having an adhesive layer according to claim 1, wherein The laser is a CO2 laser.

4. The method for producing a laminated film having an adhesive layer according to claim 1, wherein In the outer shape processing step, the carrier film side of the workpiece film is sucked by a processing table capable of adsorbing the workpiece film, and the workpiece film is slid in the longitudinal direction on the processing table, and the laser is irradiated and scanned on the workpiece film from the second film layer side.

5. The method for producing a laminated film having an adhesive layer according to claim 1, wherein The first and second slits extending in a direction intersecting the longitudinal direction of the workpiece film are formed adjacent to each other in the longitudinal direction, and the distance between the adhesive layers adjacent to each other in the longitudinal direction through the first and second slits is 2 mm or less. 6 . The method for producing a laminated film having an adhesive layer according to claim 1 , wherein: The laser is a Gaussian laser.

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