JP2024051399A - Method for producing laminated film having pressure-sensitive adhesive layer - Google Patents

Abstract

[Problem] To provide a manufacturing method of a laminated film suitable for efficiently manufacturing a large-sized laminated film having a soft adhesive layer. [Solution] The manufacturing method of the present invention includes a preparation step and an external shape processing step. In the preparation step, a long work film W is prepared, which is provided with a carrier film C, a film layer 10, an original adhesive layer 20, and a film layer 30 in the thickness direction H in that order. In the external shape processing step, while the work film W is traveling in the flow direction D1, a laser processing device equipped with multiple galvano scanners S irradiates the work film W with laser light from the film layer 30 side to cut the original adhesive layer 20 and the film layer 30 on the film layer 10. In this step, the galvano scanners S are set in a one-to-one correspondence with the same number of scanning regions R as the galvano scanners S, which are set on the work film W so as to be continuous in the width direction D2 of the work film W, and the laser light is scanned within one scanning region R by each galvano scanner S. [Selected Figure] FIG. 1

Description

The present invention relates to a method for producing a laminated film having a pressure-sensitive adhesive layer.

A display panel has a laminated structure including elements such as a pixel panel, a polarizing film, a touch panel, and a cover film. In the manufacturing process of such a display panel, for example, an optically transparent adhesive sheet (optical adhesive sheet) is used to bond the elements included in the laminated structure. The optical adhesive sheet is manufactured, for example, in a form in which both sides of the sheet are covered with release liners (in the form of a laminated film having an adhesive layer).

Meanwhile, development of display panels that can be repeatedly folded (foldable), for example, for smartphones and tablet terminals, is progressing. Specifically, a foldable display panel can be repeatedly deformed between a curved shape and a flat, non-bent shape. In such a foldable display panel, each element in the laminated structure is made to be repeatedly foldable, and a thin optical adhesive sheet is used to bond between such elements. Optical adhesive sheets for flexible devices such as foldable display panels are described, for example, in Patent Document 1 below.

JP 2018-111754 A

Adhesive sheets for flexible devices are conventionally manufactured, for example, as follows:

First, as shown in FIG. 7A, a laminated film 90 is prepared as a long raw film. The laminated film 90 has a release liner 91, an adhesive layer 92, and a release liner 93, in that order in the thickness direction H. The release liner 91 is releasably attached to one side of the adhesive layer 92. The release liner 93 is releasably attached to the other side of the adhesive layer 92. This laminated film 90 is run down a production line while being supported on a carrier film (not shown).

7B, the adhesive layer 92 of the laminated film 90 is pressed to form a plurality of sheet-like optical adhesive sheets 92A (external shape processing step). In the press processing, a press machine capable of pressing by the roll-to-roll method is used. Specifically, in the press processing, a processing blade (not shown) is pressed into the laminated film 90 from the release liner 93 side to the release liner 91. This forms an optical adhesive sheet 92A of a predetermined planar shape. In this step, a peripheral portion 92a is formed around the optical adhesive sheet 92A in the adhesive layer 92. The release liner 93 is also pressed to form a release liner 93A of the same planar shape as the adhesive layer 92, and a peripheral portion 93a is formed around the release liner 93A. In addition, in this step, a cutting groove 95 is formed in the laminated film 90 as shown in FIG. 8. The cutting groove 95 is formed by pressing the adhesive layer 92 and the release liner 93 in the planar direction D with a processing blade that penetrates the adhesive layer 92 and the release liner 93. The edge portions E, E of the optical adhesive sheet 92A and the peripheral portion 92a that are adjacent on the release liner 91 face each other.

After this external processing step, as shown in FIG. 7C, the peripheral portions 92a and 93a are removed from the release liner 91 (removal step). Then, as shown in FIG. 7D, the long release liner 91 is cut into sheet-shaped release liners 91A. This results in a sheet-shaped laminate film having an adhesive layer (release liner 91A/optical adhesive sheet 92A/release liner 93A).

Optical adhesive sheets for flexible devices are required to be highly flexible so that they can conform to the adherend when the device is bent and have excellent stress relaxation properties. However, in the above-mentioned manufacturing method, the softer the adhesive layer 92, the more likely it is that the edge portions E, E of the optical adhesive sheet 92A and the peripheral portion 92a adjacent to each other on the release liner 91 will deform and bulge outward after the contour processing step (FIG. 7B), as shown by the dashed line in FIG. 8. Specifically, the edge portions E, E that have been opened up by the pressing of the processing blade during press processing are more likely to deform and return to their original positions (reversible deformation).

Such deformation of the edge portion E causes adjacent edge portions E, E to come into contact with each other and adhere to each other (blocking). If blocking occurs between the edge portions E, E, the peripheral portions 92a, 93a cannot be properly removed in the removal process (Figure 7C). Blocking between the edge portions E, E reduces the manufacturing yield of the laminated film having the adhesive layer.

In the external processing step of the above-mentioned manufacturing method, laser processing may be used instead of press processing. Figure 9 shows a laser processing machine 200 as an example of a conventional roll-to-roll type laser processing machine.

The laser processing machine 200 is a gantry type laser processing machine including a processing stage 210, a gantry device 220, a laser head 230, and an oscillator 240. The gantry device 220 includes a pair of guides 221, a first movable unit 222, and a second movable unit 223. The first movable unit 222 is attached to each guide 221 so as to be slidable in the flow direction D1 of the work film. The second movable unit 223 is attached to the first movable unit 222 so as to be slidable in the width direction D2 of the work film. The laser head 230 is fixed to the second movable unit 223. The gantry device 220 allows the laser head 230 to move in the flow direction D1 and the width direction D2 above the processing stage 210. The oscillator 240 also generates laser light. The laser light is guided to the laser head 230 via a predetermined optical path (schematically represented by a dotted line in FIG. 9), and is irradiated from the laser head 230 onto the processing stage 210.

In the contour processing process using the laser processing machine 200, the laminated film 90 as the work film is flowed on the processing stage 210 in the flow direction D1, while the laser head 230 irradiates the laminated film 90 with laser light. The position of the laser head 230 is controlled by the gantry device 220. Specifically, the gantry device 220 moves the laser head 230 in the flow direction D1 and the width direction D2 as necessary so that the irradiation spot of the laser light on the laminated film 90 follows the intended cutting line. That is, the gantry device 220 scans the laminated film 90 with laser light. By such laser processing, a plurality of sheet-like optical adhesive sheets 92A (FIG. 7B) are sequentially formed on the laminated film 90.

In such conventional laser processing, scanning of the laser irradiation points on the laminated film 90 is performed by moving a single laser head 230 by the gantry device 220 as described above. However, the movable units 222, 223 of the gantry device 220 are heavy and are not suitable for moving the laser head 230 at high speed. In other words, laser processing using the gantry-type laser processing machine 200 is not suitable for scanning the laser irradiation points at high speed. Therefore, in this laser processing, the larger the dimension of the work film in the width direction D2 and the larger the manufacturing object (laminated film having an adhesive layer), the more it is necessary to reduce the speed (conveying speed) of the work film in the flow direction D1. This reduces the manufacturing efficiency of the laminated film having an adhesive layer. In addition, the gantry-type laser processing machine 200 requires a relatively large gantry device 220, which increases the size of the manufacturing line.

The present invention provides a method for manufacturing a laminate film that is suitable for efficiently producing a large-sized laminate film having a soft adhesive layer.

The present invention [1] includes a preparation step of preparing a long work film having a carrier film, a first film layer, an original adhesive layer, and a second film layer in this order in the thickness direction, and an outline processing step of irradiating the work film with laser light from the second film layer side by a laser processing device equipped with multiple galvanometer scanners while running the work film in the length direction, thereby cutting the original adhesive layer and the second film layer on the first film layer, and includes a manufacturing method of a laminated film having an adhesive layer, in which the outline processing step includes a manufacturing method of a laminated film having an adhesive layer, in which the work film is set to be connected in the width direction of the work film, and the same number of scanning areas as the galvanometer scanners are set in a one-to-one correspondence with the multiple galvanometer scanners, and the laser light is scanned within one scanning area by each galvanometer scanner.

In the contour processing step of this manufacturing method, as described above, the original adhesive layer on the first film layer of the work film is cut by irradiation with laser light. As a result, in the original adhesive layer, an individualized adhesive layer having a predetermined planar shape and a peripheral portion around the adhesive layer are formed. In the portion where the original adhesive layer is irradiated with the laser light, the material of the original adhesive layer is evaporated and removed. That is, in the contour processing step, the adhesive layer and the peripheral portion are separated in the original adhesive layer by partial removal of the original adhesive layer. Since the original adhesive layer is not cut into the adhesive layer and the peripheral portion by the pressing of the press blade, the above-mentioned return deformation does not occur between the adhesive layer and the peripheral portion. Such a contour processing step is suitable for suppressing the above-mentioned blocking between the adhesive layer and the peripheral portion even when the adhesive layer is soft and therefore easily deformed.

In addition, as described above, in the contour processing step of the present manufacturing method, multiple galvanometer scanners are used. Multiple scanning areas are set on the work film so as to be continuous in the width direction of the film. The number of galvanometer scanners is the same as the number of scanning areas, and the galvanometer scanners and the scanning areas correspond one-to-one. Then, each galvanometer scanner scans the laser light within one scanning area. In such a contour processing step, it is not necessary to scan the laser light using a gantry device. Therefore, the process is suitable for realizing high-speed processing of the work film, and therefore suitable for ensuring a high conveying speed of the work film. In addition, in the contour processing step, multiple scanning areas are continuous in the width direction of the work film. Therefore, the process is suitable for suppressing a decrease in the conveying speed of the work film even when the work film is wide and a large-sized laminated film is formed on the work film. The present manufacturing method including such a contour processing step is suitable for efficiently manufacturing a laminated film having an adhesive layer.

As described above, this manufacturing method is suitable for efficiently producing large-sized laminated films with soft adhesive layers.

The present invention [2] includes the method for manufacturing a laminated film having an adhesive layer described in [1] above, in which the laser processing device is equipped with a processing stage capable of sucking in the workpiece film, and in the contour processing step, the workpiece film is slid over the processing stage while being sucked into the processing stage.

This configuration is preferable for focusing the laser light on the original adhesive layer of the work film with high precision during the contour processing step, and is therefore preferable for cutting the original adhesive layer with high precision.

The present invention [3] includes a method for manufacturing a laminated film having an adhesive layer as described in [1] or [2] above, in which the positions of the multiple galvanometer scanners in the width direction of the work film are fixed in the contour processing step.

In this configuration, no moving device such as a gantry device is required in the contour processing step to translate the galvanometer scanner in the width direction and/or flow direction relative to the work film. The absence of such a moving device is preferable for cutting the original adhesive layer with high precision in the contour processing step. In addition, the absence of a moving device helps to save space on the production line in which this manufacturing method is implemented and reduces production costs.

1A shows a process of preparing a laminated film, FIG. 1B shows a contour processing process, FIG. 1C shows a removal process, and FIG. 1D shows a cutting process, according to one embodiment of the method for producing a laminated film having a pressure-sensitive adhesive layer of the present invention. FIG. FIG. 4 is a cross-sectional view showing a contour processing step. FIG. FIG. 2 is a schematic diagram of an internal configuration of a laser processing unit. FIG. 1 is a perspective view of an example of a galvanometer scanner. 7A shows an example of a conventional manufacturing method for a laminated film having a pressure-sensitive adhesive layer, in which Fig. 7A shows a step of preparing a laminated film, Fig. 7B shows a contour processing step, Fig. 7C shows a removal step, and Fig. 7D shows a cutting step. FIG. 7C is a partially enlarged schematic cross-sectional view of a cutting portion in the contour processing step shown in FIG. 7B. 1 illustrates an example of a conventional laser processing device.

The method for manufacturing a laminated film according to one embodiment of the present invention is a roll-to-roll method for manufacturing a sheet-shaped laminated film having an adhesive layer. As shown in Figures 1A to 1D, this manufacturing method includes a preparation process (Figure 1A), a contour processing process (Figure 1B), a removal process (Figure 1C), and a cutting process (Figure 1D).

In the preparation step, as shown in FIG. 1A, a laminated film X is prepared as a long raw film. In the production line in which this manufacturing method is carried out, the laminated film X is prepared on a carrier film C.

The laminated film X comprises a film layer 10 (first film layer), an original adhesive layer 20, and a film layer 30 (second film layer) in this order in the thickness direction H. The original 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 laminated film X extends in a planar direction perpendicular to the thickness direction H.

The carrier film C is a single-sided adhesive film having an adhesive surface on one side in the thickness direction H. The carrier film C and the laminated film X form the work film W. In the work film W, the adhesive surface of the carrier film C is bonded to the film layer 10 side of the laminated film X. Specifically, the work film W comprises the carrier film C, the film layer 10, the original adhesive layer 20, and the film layer 30 in this order in the thickness direction H. In addition, in this embodiment, the carrier film C is wider than the laminated film X in the width direction D2 (FIGS. 2 and 3) perpendicular to the flow direction D1 (FIG. 2) of the work film W. The laminated film X is disposed at the center position of the width direction D2 on the carrier film C. The width (length in the width direction D2) of the laminated film X is, for example, 200 mm or more, preferably 280 mm or more, more preferably 400 mm or more, and, for example, 1200 mm or less, preferably 1000 mm or less, more preferably 800 mm or less. Such a work film W is run through the production line.

The film layer 10 is, for example, a release liner, a functional optical film, or a substrate film (support film).

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 as the release liner is in peelable contact with the first surface 20a of the original adhesive layer 20. The surface of such a film layer 10 (the surface on the original adhesive layer 20 side) is preferably subjected to a release treatment. Examples of the release treatment include a silicone release treatment and a fluorine release treatment. From the viewpoint of ensuring the protective function for the adhesive layer, the thickness of the release liner is preferably 10 μm or more, more preferably 20 μm or more, and even more preferably 30 μm or more. From the viewpoint of making the laminated film X thinner, the thickness of the release liner is preferably 200 μm or less, more preferably 150 μm or less, and even more preferably 100 μm or less.

Examples of functional optical films include polarizing films and phase difference films. The functional optical film may be other optical films such as panel reinforcement materials. When the film layer 10 is a functional optical film, the first surface 20a of the raw adhesive layer 20 is bonded to such a film layer 10. The film layer 10 as a functional optical film and the raw adhesive layer 20 form a functional optical film with an adhesive layer.

The polarizing film may be, for example, a hydrophilic polymer film that has been dyed with a dichroic substance and then stretched. The dichroic substance may be, for example, iodine and a dichroic dye. The hydrophilic polymer film may be, for example, a polyvinyl alcohol (PVA) film, a partially formalized PVA film, and a partially saponified film of an ethylene-vinyl acetate copolymer. The polarizing film may also be a polyene-oriented film. Examples of materials for the polyene-oriented film include a dehydrated PVA film and a dehydrochlorinated polyvinyl chloride film. The polarizing film may have a protective film bonded to one side and/or the other side in the thickness direction via an adhesive. The thickness of the polarizing film is preferably 10 μm or more, more preferably 20 μm or more, from the viewpoint of ensuring the function, strength, and durability of the polarizing film. The thickness of the polarizing film is preferably 500 μm or less, more preferably 300 μm or less, from the viewpoint of making the laminated film X thinner.

Examples of the retardation film include λ/2 wavelength film, λ/4 wavelength film, and viewing angle compensation film. Examples of the material of the retardation film include polymer films that are birefringent due to stretching treatment. Examples of the polymer film include cellulose film and polyester film. Examples of the cellulose film include triacetyl cellulose film. Examples of the polyester film include polyethylene terephthalate film, polyethylene naphthalate film, and polybutylene terephthalate film. Examples of the retardation film include a film having a substrate such as a cellulose film and an orientation layer of a liquid crystal compound such as a liquid crystal polymer on the substrate. The thickness of the retardation film is preferably 1 μm or more, more preferably 2 μm or more, from the viewpoint of ensuring the function and strength of the retardation film. The thickness of the retardation film is preferably 100 μm or less, more preferably 80 μm or less, from the viewpoint of making the laminated film X thinner.

Materials for the base film include, for example, the materials mentioned above as materials for the release liner. When the film layer 10 is a base film, the first surface 20a of the raw adhesive layer 20 is bonded to such a film layer 10. The film layer 10 as a base film and the raw adhesive layer 20 form a single-sided adhesive sheet. From the viewpoint of ensuring the strength as a base, the thickness of the base film is preferably 10 μm or more, more preferably 20 μm or more, and even more preferably 30 μm or more. From the viewpoint of making the laminated film X thinner, the thickness of the base film is preferably 200 μm or less, more preferably 150 μm or less, and even more preferably 100 μm or less.

The raw 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 adhesiveness. Examples of base polymers 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 types. From the viewpoint of ensuring good transparency and adhesiveness in the raw adhesive layer 20, an acrylic polymer is preferably used as the base polymer.

The acrylic polymer is a copolymer of monomer components containing 50% or more by mass of (meth)acrylic acid ester. "(Meth)acrylic" means acrylic and/or methacrylic. As the (meth)acrylic acid ester, preferably, an alkyl (meth)acrylic acid ester is used, and more preferably, an alkyl (meth)acrylic acid ester having 1 to 20 carbon atoms in the alkyl group is used. Examples of the alkyl (meth)acrylic acid ester 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, and dodecyl (meth)acrylate.

The monomer component may include a copolymerizable monomer that is copolymerizable with the (meth)acrylic acid alkyl ester. Examples of the copolymerizable monomer include a monomer having a polar group. Examples of the polar group-containing monomer include a hydroxy group-containing monomer, a monomer having a nitrogen atom-containing ring, and a carboxy group-containing monomer. The polar group-containing monomer is useful for modifying the acrylic polymer, such as introducing a crosslinking point into the acrylic polymer and ensuring the cohesive strength of the acrylic polymer. Examples of the hydroxy group-containing monomer include 2-hydroxyethyl (meth)acrylate, 2-hydroxypropyl (meth)acrylate, and 2-hydroxybutyl (meth)acrylate. Examples of the monomer having a nitrogen atom-containing ring include N-vinyl-2-pyrrolidone, N-methylvinylpyrrolidone, N-vinylpyridine, N-vinylpiperidone, N-vinylimidazole, and N-(meth)acryloyl-2-pyrrolidone.

The base polymer preferably has a crosslinked structure. Methods for introducing a crosslinked structure into the base polymer include a method (first method) in which a base polymer having a functional group capable of reacting with a crosslinking agent and the crosslinking agent are blended into an adhesive composition, and the base polymer and the crosslinking agent are reacted in the adhesive layer, and a method (second method) in which a polyfunctional monomer as a crosslinking agent is included in the monomer components forming the base polymer, and a base polymer having a branched structure (crosslinked structure) introduced into the polymer chain is formed by polymerization of the monomer components. These methods may be used in combination.

The crosslinking agent used in the first method includes, for example, a compound that reacts with functional groups (such as hydroxyl groups and carboxyl groups) 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 types.

In the second method, a monofunctional monomer for forming a base polymer is first polymerized (preliminary polymerization), thereby preparing a prepolymer composition containing a partial polymer (a mixture of a polymer with a low degree of polymerization and unreacted monomer). Next, a polyfunctional monomer is added as a crosslinking agent to the prepolymer composition, and then the partial polymer and the polyfunctional monomer are polymerized (main polymerization). Examples of the polyfunctional monomer include polyfunctional (meth)acrylates containing two or more ethylenically unsaturated double bonds in one molecule. Examples of the polyfunctional (meth)acrylates include ethylene glycol di(meth)acrylate, diethylene glycol di(meth)acrylate, 1,6-hexanediol di(meth)acrylate, trimethylolpropane tri(meth)acrylate, pentaerythritol tri(meth)acrylate, and dipentaerythritol hexa(meth)acrylate.

The base polymer can be formed by polymerizing the above-mentioned monomer components. Examples of the polymerization method include solution polymerization, solvent-free photopolymerization (e.g., UV polymerization), bulk polymerization, and emulsion polymerization. For example, ethyl acetate and toluene are used as the solvent for solution polymerization. For example, a thermal polymerization initiator or a photopolymerization initiator is used as the polymerization initiator.

From the viewpoint of ensuring the cohesive strength of the raw 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 million or less, more preferably 3 million or less, and even more preferably 2 million or less. The weight average molecular weight of the base polymer is measured by gel permeation chromatography (GPC) and calculated in terms of polystyrene.

The glass transition temperature (Tg) of the base polymer is preferably 0°C or lower, more preferably -10°C or lower, and even more preferably -20°C or lower, from the viewpoint of ensuring the softness of the original adhesive layer 20. The glass transition temperature is, for example, -80°C or higher.

For the glass transition temperature (Tg) of the base polymer, the glass transition temperature (theoretical value) calculated based on the Fox formula below can be used. The Fox formula is a relational expression between the glass transition temperature Tg of a polymer and the glass transition temperature Tgi of a homopolymer of a monomer constituting the polymer. In the Fox formula below, Tg represents the glass transition temperature (°C) of the polymer, Wi represents the weight fraction of the monomer i constituting the polymer, and Tgi represents the glass transition temperature (°C) of a homopolymer formed from the monomer i. For the glass transition temperature of the homopolymer, a literature value can be used. For example, the glass transition temperatures of various homopolymers are listed in "Polymer Handbook" (4th edition, John Wiley & Sons, Inc., 1999). On the other hand, the glass transition temperature of a homopolymer of a monomer can also be calculated by the method specifically described in JP-A-2007-51271.

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

The adhesive composition may contain other components as necessary. Examples of the other components include a solvent, a silane coupling agent, an ultraviolet absorber, a tackifier, a softener, and an antioxidant. Examples of the solvent include a polymerization solvent that is used as necessary during polymerization of the acrylic polymer, and a solvent that is added to the polymerization reaction solution after polymerization. Examples of the solvent that is used include ethyl acetate and toluene.

The haze of the raw adhesive layer 20 is preferably 3% or less, more preferably 2% or less, and even more preferably 1% or less. The haze of the raw 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 Co., Ltd. and the "HM-150" manufactured by Murakami Color Research Laboratory Co., Ltd.

The shear storage modulus of the raw adhesive layer 20 at 25 ° C. is preferably 10 kPa or more, more preferably 15 kPa or more, even more preferably 20 kPa or more, and particularly preferably 25 kPa or more, from the viewpoint of ensuring the cohesive force of the raw adhesive layer 20. The shear storage modulus of the raw adhesive layer 20 at 25 ° C. is preferably 1000 kPa or less, more preferably 700 kPa or less, even more preferably 500 kPa or less, and particularly preferably 300 kPa or less, from the viewpoint of realizing the softness required for an optical adhesive sheet for flexible display panel use in the raw adhesive layer 20. Examples of methods for adjusting the shear storage modulus include selecting the type of base polymer in the raw adhesive layer 20, adjusting the molecular weight, adjusting the blending amount, adjusting the glass transition temperature, and adjusting the degree of crosslinking. Examples of methods for adjusting the shear storage modulus include selecting components other than the base polymer in the raw adhesive layer 20 and adjusting the blending amount. The shear storage modulus of the adhesive layer is determined by dynamic viscoelasticity measurement. The measurement can be performed using the Advanced Rheometric Expansion System (ARES), a dynamic viscoelasticity measuring device manufactured by Rheometric Scientific. The measurement mode is shear mode, the measurement temperature range is -40°C to 100°C, the heating rate is 5°C/min, and the frequency is 1Hz.

In this embodiment, the film layer 30 is a release liner. Examples of materials for the release liner include polyester, polyolefin, and polycarbonate. Specifically, the materials for the release liner include those described above for the film layer 10. The film layer 30 as a release liner is in peelable contact with the second surface 20b of the original adhesive layer 20. The surface of such a film layer 30 (the surface on the original adhesive layer 20 side) is preferably subjected to a release treatment. Examples of the release treatment include a silicone release treatment and a fluorine release treatment. The thickness of the film layer 30 is, for example, 10 μm or more, and, for example, 200 μm or less.

The laminated film X can be manufactured, for example, as follows. First, the above-mentioned adhesive composition is applied onto the film layer 10 to form a coating film. Next, the film layer 30 is laminated onto the coating film on the film layer 10. Next, the coating film between the film layers 10 and 30 is dried, and the coating film is irradiated with light as necessary. In this way, the original adhesive layer 20 is formed between the film layers 10 and 30. Examples of methods for applying the adhesive composition include roll coating, kiss roll coating, gravure coating, reverse coating, roll brushing, spray coating, dip roll coating, bar coating, knife coating, air knife coating, curtain coating, lip coating, and die coating. The drying temperature for the coating film is, for example, 50°C to 200°C. The drying time is, for example, 5 seconds to 20 minutes.

In the external processing step, as shown in FIG. 1B, laser processing is performed on the workpiece film W. Specifically, a laser processing device equipped with multiple galvanometer scanners irradiates the workpiece film W with laser light L from the film layer 30 side to cut the original adhesive layer 20 and the film layer 30 on the film layer 10. As a result, in the original adhesive layer 20, an individualized adhesive layer 21 and a peripheral portion 22 around the adhesive layer 21 are formed. In addition, in the film layer 30, a film 31 on the adhesive layer 21 and a peripheral portion 32 around the film 31 are formed. A half-cut groove 10a is formed in the film layer 10. The half-cut groove 10a is formed along the edge 21a of the adhesive layer 21. In this embodiment, a laser processing device 100 is used as a laser processing device equipped with multiple galvanometer scanners, as shown in FIGS. 2 to 4.

In this embodiment, the laser processing device 100 includes a processing stage 110, a plurality of laser processing units 120, and a control unit (not shown). Figures 2 to 4 exemplarily illustrate a case in which the laser processing device 100 includes four laser processing units 120A, 120B, 120C, and 120D.

The processing stage 110 is a stage that supports the work film W flowing through the production line. As shown in FIG. 3, the processing stage 110 has a support table 111 and a suction path 112. The support table 111 forms a support surface for the work film W in the processing stage 110. The support table 111 has a plurality of suction holes 111a that penetrate the support table 111 in the thickness direction. The suction path 112 is a space formed in the processing stage 110. The suction path 112 is located below the support table 111. Each suction hole 111a of the support table 111 communicates with the suction path 112. The suction path 112 is connected to the suction path of a vacuum pump (not shown). The suction path 112 is depressurized by the operation of the vacuum pump. The vacuum pump can select an operating state or a non-operating state according to the control by the control unit. When the workpiece film W is on the support table 111, the suction path 112 is depressurized, and the workpiece film W is sucked onto the support table 111 of the processing stage 110.

A pair of nip rollers N1, N1 are arranged on the upstream side of the manufacturing line of the processing stage 110. The work film W is pinched between the pair of nip rollers N1, N1, and each nip roller N1 is rotated at a constant speed to pull and send the work film W toward the processing stage 110. Meanwhile, a pair of nip rollers N2, N2 are arranged on the downstream side of the manufacturing line of the processing stage 110. The work film W is pinched between the pair of nip rollers N2, N2, and each nip roller N2 is rotated at a constant speed to pull and send the work film W toward the downstream side of the nip rollers N2, N2. The work film W is caused to flow in the length direction of the film (flow direction D1) on the support stage 111 of the processing stage 110 by the nip rollers N1, N1 and the nip rollers N2, N2. In this state, the suction path 112 of the processing stage 110 is depressurized, so that the workpiece film W slides along the processing stage 110 while being sucked into the processing stage 110.

As shown in FIG. 5, 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 S. The laser light source 122, the beam expander 123, the movable lens 124, the condenser lens 125, and the galvanometer scanner S are housed in the housing 121. The housing 121 has a laser light emission port (not shown).

The laser light source 122 oscillates the laser light L. Examples of the laser light source 122 include a gas laser light source, a solid-state laser light source, and a semiconductor laser light source. Examples of the gas laser light source include a laser light source that pulses laser light having a wavelength in the infrared region. Examples of such laser light sources include a CO laser light source (5 μm) and a CO ₂ laser light source (9.3 to 10.6 μm) (the numbers in parentheses indicate the wavelength of the laser light from the laser light source. The same applies below to the laser light sources). Examples of the gas laser light source include an excimer laser light source. Examples of the excimer laser light source include an F ₂ excimer laser light source (157 nm), an ArF excimer laser light source (193 nm), a KrF excimer laser light source (248 nm), and a XeCl excimer laser light source (308 nm). Examples of the solid-state laser light source include an Nd:YAG laser light source (1064 nm). Examples of the semiconductor laser light source include a semiconductor laser light source with a wavelength of 405 nm.

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

The movable lens 124 is a lens that can be displaced in the optical axis direction of the laser light L. As the movable lens 124 is displaced in the optical axis direction, the position of the focus of the laser light L focused by the focusing lens 125 (the position of the focus on the work film W) varies. The position of the movable lens 124 in the optical axis direction can be adjusted according to the control by the control unit (position control of the movable lens 124).

The laser light L that passes through the focusing lens 125 is reflected by the galvanometer scanner S. As shown in FIG. 6, the galvanometer scanner S includes 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).

The galvanometer mirror 126 has a mirror surface 126a capable of reflecting the laser light L. The galvanometer motor 127 has a motor shaft 127a connected to the galvanometer mirror 126. The motor shaft 127a extends in a first direction. The first direction is preferably perpendicular to each of the flow direction D1 and width direction D2 of the work film W. The galvanometer motor 127 can swing the direction in which the mirror surface 126a of the galvanometer mirror 126 faces (first mirror surface direction) around a rotation axis extending along the motor shaft 127a. The galvanometer motor 127 can control the first mirror surface direction of the galvanometer mirror 126 according to the control by the control unit.

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

In the galvanometer scanner S, the laser light L is reflected successively by the mirror surface 126a of the galvanometer mirror 126 and the mirror surface 128a of the galvanometer mirror 128. After passing through the laser light emission port of the housing 121, the laser light L is irradiated onto the work film W on the processing stage 110.

In this process, a plurality of scanning regions R (shown in FIGS. 3 and 4) are set on the work film W so as to be continuous in the width direction D2 of the work film W. Specifically, the plurality of scanning regions R are set so as to divide the laminated film X on the work film W into a plurality of regions in the width direction D2. The number of the laser processing units 120 (equipped with galvanometer scanners S) is the same as the number of scanning regions R. That is, the number of the galvanometer scanners S is the same as the number of scanning regions R. FIGS. 3 and 4 exemplarily illustrate a case in which four scanning regions R1, R2, R3, and R4 are set so as to be continuous in the width direction of the work film W (FIG. 3 shows the galvanometer scanner S and the laser processing unit 120 as a schematic representation). The scanning region R1 corresponds to the galvanometer scanner S of the laser processing unit 120A. The scanning region R2 corresponds to the galvanometer scanner S of the laser processing unit 120B. The scanning region R3 corresponds to the galvanometer scanner S of the laser processing unit 120C. The scanning region R4 corresponds to the galvanometer scanner S of the laser processing unit 120D. In other words, the galvanometer scanner S and the scanning region R correspond one-to-one.

The length in the width direction D2 of the scanning region R is, for example, 30 mm or more, preferably 50 mm or more, more preferably 100 mm or more, and is, for example, 300 mm or less, preferably 250 mm or less, more preferably 200 mm or less. The lengths in the width direction D2 of the four scanning regions R may all be the same, may be partially different, or may all be different from each other.

In each laser processing unit 120, the laser light L is scanned on the work film W by controlling the first and second mirror surface directions of the galvanometer motors 127 and 129. Specifically, the laser light L is scanned in the flow direction D1 and the surface direction D2 by controlling the first and second mirror surface directions of the galvanometer motors 127 and 129 so that the irradiation spot on the work film W of the laser light L from the laser processing unit 120 follows the intended cutting line on the work film W. In each laser processing unit 120, the laser light L is scanned within a predetermined range (scanning area) centered substantially directly below the galvanometer scanner S. In addition, the movable lens 124 is position-controlled according to the first and second mirror surface directions so that the size (spot diameter) of the irradiation spot of the scanned laser light L is the same regardless of the change in the incident angle with respect to the work film W (the angle formed by the normal direction of the film surface and the optical axis direction of the laser light L).

Figure 4 shows an example of the arrangement of the scanning area AR of the laser light L for each laser processing unit 120. In Figure 4, the scanning area AR1 of the laser processing unit 120A, the scanning area AR2 of the laser processing unit 120B, the scanning area AR3 of the laser processing unit 120C, and the scanning area AR4 of the laser processing unit 120D are arranged in this order with a gap in the flow direction D1, and are arranged in this order without a gap in the width direction D2. By arranging the multiple scanning areas AR without a gap in the width direction D2, the outer shape processing of the work film W can be performed in the width direction D2 without interruption. In this embodiment, each laser processing unit 120 is arranged so that each scanning area AR is arranged in this way. Each laser processing unit 120 is connected to, for example, a predetermined frame part of the laser processing device 100. As a result, the positions of the multiple laser processing units 120 in the flow direction D1 and the width direction D2 of the work film W are fixed. That is, the positions of the multiple galvanometer scanners S in the flow direction D1 and width direction D2 of the work film W are fixed. The multiple scanning areas AR are also fixed. The multiple scanning areas AR may be arranged without any gaps in the flow direction D1. The multiple laser processing units 120 may be arranged in the laser processing device 100 so that the multiple scanning areas AR are arranged without any gaps in the flow direction D1.

In the laser processing device 100, as shown in FIG. 4, a certain area in the longitudinal direction of the workpiece film W is first laser processed in scanning area AR1, then laser processed in scanning area AR2, then laser processed in scanning area AR3, and then laser processed in scanning area AR4. In this embodiment, for example, it is as follows.

In the scanning area AR1, in this embodiment, while a partial line (first partial line to be cut) from point P1 to point P2 on the rectangular planned cutting line (not shown) passes through the scanning area AR1, the irradiation spot of the laser light L from the laser processing unit 120A scans the first partial line to be cut from point P1 to point P2 (first scan). This forms a cutting line T1 on the work film W.

In the scanning area AR2, while a partial line from point P1 to point P3 in the line to be cut (second partial line to be cut) passes through the scanning area AR2, the irradiation spot of the laser light L from the laser processing unit 120B scans the second partial line to be cut from point P1 to point P3 or from point P3 to point P1 (second scanning). As a result, a cutting line T2 that connects the cutting line T1 at point P1 is formed on the work film W. Also, in the scanning area AR2, while a partial line from point P2 to point P4 in the line to be cut (third partial line to be cut) passes through the scanning area AR2, the irradiation spot of the laser light L from the laser processing unit 120B scans the third partial line to be cut from point P2 to point P4 or from point P2 to point P4 (third scanning). As a result, a cutting line T3 that connects the cutting line T1 at point P2 is formed on the work film W.

In the scanning area AR3, while the partial line from point P3 to point P5 in the line to be cut (fourth partial line to be cut) passes through the scanning area AR3, the irradiation spot of the laser light L from the laser processing unit 120C scans the fourth partial line to be cut from point P3 to point P5 or from point P5 to point P3 (fourth scan). As a result, a cutting line T4 that connects the cutting line T2 at point P3 is formed on the work film W. In the scanning area AR3, while the partial line from point P4 to point P6 in the line to be cut (fifth partial line to be cut) passes through the scanning area AR3, the irradiation spot of the laser light L from the laser processing unit 120C scans the fifth partial line to be cut from point P4 to point P6 or from point P6 to point P4 (fifth scan). As a result, a cutting line T5 that connects the cutting line T3 at point P4 is formed on the work film W.

In the scanning area AR4, while the partial line from point P5 to point P6 on the line to be cut (sixth partial line to be cut) passes through the scanning area AR4, the irradiation spot of the laser light L from the laser processing unit 120D scans the sixth partial line to be cut from point P5 to point P6 (sixth scan). This forms a cutting line T6 on the work film W. The cutting line T6 is connected to the cutting line T4 at point P5, and is also connected to the cutting line T5 at point P6.

In each of the first to sixth scans, specifically, the control unit controls the galvanometer scanner S (galvanometer motors 127, 129) so that the position of the irradiation spot, which is determined by the combined speed (vector) of the transport speed (vector) of the work film W and the scanning speed (vector) of the laser light L, follows the line of the portion to be cut that passes through the scanning area AR.

In the above-described external shape processing step, when a _CO2 laser is used as the laser light L, the pulse width of the laser light L is, for example, 0.5 to 50 μsec, the pulse frequency of the laser light L is, for example, 1 to 200 kHz, the output of the laser light L is, for example, 2 to 250 W, and the spot diameter of the laser light L is, for example, 50 to 200 μm. When a short pulse laser is used as the laser light L, the pulse width of the laser light L is, for example, 0.2 to 1000 picoseconds, the pulse frequency of the laser light L is, for example, 0.1 to 1000 MHz, the output of the laser light L is, for example, 2 to 250 W, and the spot diameter of the laser light L is, for example, 5 to 100 μm.

Next, in the removal process, the peripheral portions 22 and 32 are removed from the film layer 10 as shown in FIG. 1C.

Next, in the cutting process, as shown in FIG. 1D, the film layer 10 is cut into sheets of film 11. Examples of cutting methods include cutting by laser processing and cutting by press processing.

In this manner, laminated film Y (a laminated film having an adhesive layer) can be manufactured. After film 31 is peeled off from adhesive layer 21, another film may be laminated to adhesive layer 21.

In the contour processing step of this manufacturing method, as described above, the original adhesive layer 20 on the film layer 10 of the work film W is cut by irradiation with laser light L. As a result, in the original adhesive layer 20, an individualized adhesive layer 21 having a predetermined planar shape and a peripheral portion 22 around the adhesive layer 21 are formed. In the portion of the original adhesive layer 20 irradiated with the laser light L, the material of the original adhesive layer 20 is evaporated and removed. That is, in the contour processing step, the adhesive layer 21 and the peripheral portion 22 are separated in the original adhesive layer 20 by partial removal of the original adhesive layer 20. Since the original adhesive layer 20 is not cut into the adhesive layer 21 and the peripheral portion 22 by the pressing of the press blade, the above-mentioned return deformation does not occur between the adhesive layer 21 and the peripheral portion 22. Such a contour processing step is suitable for suppressing the above-mentioned blocking between the adhesive layer 21 and the peripheral portion 22 even when the adhesive layer 21 is soft and therefore easily deformed.

In addition, as described above, in the contour processing step of this manufacturing method, multiple galvano scanners S are used. Multiple scanning regions R are set on the work film W so as to be continuous in the width direction D2 of the work film W. The number of galvano scanners S and the number of scanning regions R are the same, and the galvano scanners S and the scanning regions R correspond one-to-one. Then, the laser light L is scanned within one scanning region R by each galvano scanner S. In such a contour processing step, it is not necessary to scan the laser light L by a gantry device. Therefore, this process is suitable for realizing high-speed processing of the work film W, and therefore, is suitable for ensuring a high conveying speed of the work film W. In addition, in the contour processing step, multiple scanning regions R are continuous in the width direction D2 of the work film W. Therefore, this process is suitable for suppressing a decrease in the conveying speed of the work film W even when the work film W is wide and a large-sized laminated film Y is formed. This manufacturing method including such a contour processing step is suitable for efficiently manufacturing a laminated film Y having an adhesive layer 21.

As described above, this manufacturing method is suitable for efficiently manufacturing a large-sized laminated film Y having a soft adhesive layer 21.

In the contour processing step of this manufacturing method, the workpiece film W is slid along the processing stage 110 while being sucked into the processing stage 110. This is preferable for precisely focusing the laser light L on the original adhesive layer 20 of the workpiece film W in the contour processing step, and is therefore preferable for cutting the original adhesive layer 20 with high precision.

In the contour processing step of this manufacturing method, as described above, the laser light L is scanned with the position of each galvano scanner S fixed in the laser processing device 100. In this manufacturing method, a movable device such as a gantry device for translating the galvano scanner S in the width direction and/or flow direction relative to the work film is not required. The absence of such a movable device is preferable for cutting the raw adhesive layer 20 with high precision in the contour processing step. In addition, the absence of a movable device helps to save space on the manufacturing line implementing this manufacturing method and to reduce manufacturing costs.

In this manufacturing method, the number of laser processing units 120 in the laser processing apparatus 100 is not limited to four. That is, the number of galvanometer scanners S provided in the laser processing apparatus 100 is not limited to four. The number of laser processing units 120 in the laser processing apparatus 100 may be two, three, five, or six or more. That is, the number of galvanometer scanners S provided in the laser processing apparatus 100 may be two, three, five, or six or more. The same number of scanning regions R as the number of galvanometer scanners S (two, three, five, or six or more) are set on the work film W so as to be continuous in the width direction D2 of the work film W.

The laser processing unit 120 may be provided with a telecentric type fθ lens at a position where the laser light L passes after the galvano scanner S (if the laser processing unit 120 is provided with a telecentric type fθ lens, the laser processing unit 120 does not have the condenser lens 125). The fθ lens is useful for making the spot diameter of the irradiation spot of the laser light L the same regardless of the change in the incident angle of the laser light L to the work film W. When the laser processing unit 120 is provided with such an fθ lens, it is not necessarily required to provide the movable lens 124. When a telecentric type fθ lens having a diameter larger than the width (length in the width direction D2) of the scanning region R assigned to the laser processing unit 120 can be used, it is preferable to use such an fθ lens. In addition, in the laser processing unit 120, the telecentric type fθ lens and the above-mentioned movable lens 124 may be used in combination.

W Work film X Laminated film C Carrier film H Thickness direction D1 Flow direction D2 Width direction 10 Film layer (first film layer)
11 Film 20 Original adhesive layer 21 Adhesive layer 22 Periphery 30 Film layer (second film layer)
31 film 32 peripheral portion 100 laser processing device 110 processing stage 111 support table 111a suction hole 112 suction path 120 laser processing unit S galvano scanner

Claims (3)

A preparation process of preparing a long work film having a carrier film, a first film layer, an original adhesive layer, and a second film layer in this order in a thickness direction;
and a contour processing step of irradiating the work film from the second film layer side with a laser processing device having a plurality of galvano scanners while running the work film in the length direction, thereby cutting the original adhesive layer and the second film layer on the first film layer.
In the external processing step, scanning areas, the same number as the galvanometer scanners, are set on the work film so as to be connected in the width direction of the work film, and the multiple galvanometer scanners are matched one-to-one with each other, and laser light is scanned within one scanning area by each galvanometer scanner. The laser processing apparatus includes a processing stage capable of sucking the workpiece film,
The method for manufacturing a laminated film having an adhesive layer according to claim 1 , wherein in the contour processing step, the work film is slid along the processing stage while being sucked by the processing stage. The method for manufacturing a laminated film having an adhesive layer according to claim 1 or 2, wherein in the contour processing step, the positions of the multiple galvanometer scanners in the width direction of the work film are fixed.

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