Laminated film and method for producing the same

Abstract

To provide a laminated film that imparts excellent transparency even when adhered to a transparent adherend, and a method for producing the same.SOLUTION: A laminated film comprises a base layer and an adhesive layer, wherein the surface roughness of the base layer on the side opposite the adhesive layer is 0.01 μm or more and 1.50 μm or less, the surface roughness of the base layer on the adhesive layer side is 0.01 μm or more and 1.20 μm or less, and the surface roughness of the adhesive layer on the side opposite the base layer is 0.01 μm or more and 0.40 μm or less.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present disclosure relates to a laminate film and a method for producing the laminate film. [Background technology]

[0002] Conventionally, a film has been attached to the surface of an adherend for decoration or protection of the adherend. For example, Patent Document 1 discloses a polypropylene resin film made of a laminate in which an adhesive layer is laminated on one side of a base layer made of a polypropylene resin and a release layer is laminated on the other side, the release layer surface has an average surface roughness SRa of 0.200 μm or less, the adhesive layer surface has an average surface roughness SRa of 0.030 μm or less, the contact area with the adherend defined in the specification is 90% or more and 100% or less, and the film haze is in the range of 1 to 40%. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2009-287004 A Summary of the Invention [Problem to be solved by the invention]

[0004] In order to impart a design to a transparent adherend such as glass, a film on which a pattern or the like is printed may be attached to the surface of the transparent adherend. In recent years, there has been a demand for the background of the transparent adherend to be visible through the film. However, when a film is attached to a transparent adherend, it may appear cloudy, and high transparency may not be obtained.

[0005] The present invention has been made in consideration of the above-mentioned current situation, and has an object to provide a laminate film that can impart excellent transparency even when attached to a transparent substrate, and a method for producing the laminate film. [Means for solving the problem]

[0006] (1) One embodiment of the present invention is a laminate film having a base layer and a pressure-sensitive adhesive layer, wherein the surface roughness of the base layer on the side opposite the pressure-sensitive adhesive layer is 0.01 μm or more and 1.50 μm or less, the surface roughness of the base layer on the side of the pressure-sensitive adhesive layer is 0.01 μm or more and 1.20 μm or less, and the surface roughness of the pressure-sensitive adhesive layer on the side opposite the base layer is 0.01 μm or more and 0.40 μm or less.

[0007] (2) One embodiment of the present invention is a laminate film having the configuration as described above in (1), in which the base layer is a polyvinyl chloride film.

[0008] (3) An embodiment of the present invention is a laminate film having the configuration as described above in (2), wherein the polyvinyl chloride film contains a polyester-based plasticizer.

[0009] (4) An embodiment of the present invention is a laminate film having the configuration of any one of the above (1) to (3), wherein the base layer and the pressure-sensitive adhesive layer are in contact with each other.

[0010] (5) An embodiment of the present invention is a laminate film having the configuration of any one of the above (1) to (4), further comprising a separator on the side of the pressure-sensitive adhesive layer opposite the base layer.

[0011] (6) In one embodiment of the present invention, in addition to the configuration of (5) above, the separator has a surface roughness of 0.01 μm or more and 0.45 μm or less on the pressure-sensitive adhesive layer side.

[0012] (7) In one embodiment of the present invention, in addition to the configuration of (5) or (6) above, the surface of the separator opposite the pressure-sensitive adhesive layer is matte-treated.

[0013] (8) An embodiment of the present invention is a laminate film having the configuration of any one of the above (1) to (7), wherein the laminate film is a printing base film.

[0014] (9) One embodiment of the present invention is a laminate film having the configuration as described above in (8), further comprising a design layer on the surface of the base layer opposite the pressure-sensitive adhesive layer.

[0015] (10) An embodiment of the present invention is a laminate film having the configuration of any one of (1) to (9) above, wherein a haze value of a laminate comprising the base layer and the pressure-sensitive adhesive layer is 3.0% or less.

[0016] (11) Another embodiment of the present invention is a method for producing a laminated film, comprising: a base layer forming step of arranging a support sheet having a surface roughness of 0.01 μm or more and 1.60 μm or less between a first calendar roll having a surface roughness of 0.01 μm or more and 1.30 μm or less, so as to be in contact with the second calendar roll, and forming a base layer having a first side on which the support sheet is laminated and a second side in contact with the surface of the first calendar roll; an adhesive layer forming step of forming an adhesive layer on a surface of a separator having a surface roughness of 0.01 μm or more and 0.45 μm or less; and a laminating step of laminating a surface of the adhesive layer opposite to the surface in contact with the separator onto the second side of the base layer.

[0017] (12) In one embodiment of the present invention, in addition to the configuration of (11), the method for producing a laminated film further includes, prior to the base layer forming step, a step of passing between the first calendar roll and the second calendar roll to form a precursor layer for the base layer, in which the precursor layer is inverted and positioned so that the surface in contact with the surface of the first calendar roll faces the second calendar roll and the surface in contact with the surface of the second calendar roll faces the first calendar roll, and the support sheet is positioned between the second calendar roll and the surface of the precursor layer in contact with the surface of the first calendar roll. Effect of the Invention

[0018] According to the present invention, it is possible to provide a laminate film that can impart excellent transparency even when attached to a transparent adherend, and a method for producing said laminate film. [Brief description of the drawings]

[0019] [Figure 1] FIG. 1 is a cross-sectional view illustrating an example of a laminated film according to an embodiment of the present invention. [Diagram 2] FIG. 2 is a cross-sectional view illustrating a schematic diagram of another example of the laminated film according to the embodiment. [Diagram 3] 1 is a cross-sectional view showing a schematic state in which a laminated film according to an embodiment is attached to an adherend. [Figure 4A] 1A to 1C are schematic diagrams illustrating steps in a method for producing a laminated film according to an embodiment. [Figure 4B] 1A to 1C are schematic diagrams illustrating steps in a method for producing a laminated film according to an embodiment. [Figure 4C] 1A to 1C are schematic diagrams illustrating steps in a method for producing a laminated film according to an embodiment. [Diagram 5] FIG. 2 is a schematic diagram illustrating a method for testing the transparency of a laminated film. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0020] Hereinafter, an embodiment of the present invention will be described. The present invention is not limited to the contents described in the following embodiment, and appropriate design changes can be made within the scope of the configuration of the present invention.

[0021] Fig. 1 is a cross-sectional view showing a schematic example of a laminated film according to an embodiment. As shown in Fig. 1, a laminated film 10 according to an embodiment has a base layer 1 and a pressure-sensitive adhesive layer 2. The surface roughness of a surface 1a of the base layer 1 opposite to the pressure-sensitive adhesive layer 2 is 0.01 µm or more and 1.50 µm or less, the surface roughness of a surface 1b of the base layer 1 facing the pressure-sensitive adhesive layer 2 is 0.01 µm or more and 1.20 µm or less, and the surface roughness of a surface 2b of the pressure-sensitive adhesive layer 2 opposite to the base layer 1 is 0.01 µm or more and 0.40 µm or less.

[0022] By setting the surface roughness of the surface 1a of the base layer 1 opposite to the adhesive layer 2 (front side) in the above range, it is possible to obtain a glossy appearance. By setting the surface roughness of the surface 1b of the base layer 1 opposite to the adhesive layer 2 (rear side) in the above range, air is less likely to be trapped between the base layer and the adhesive layer, interfacial reflection between the base layer and the adhesive layer can be suppressed, and deformation of the adhesive layer on the surface 1b side of the adhesive layer 2 side of the base layer 1 can be suppressed. By setting the surface roughness of the surface 2b of the adhesive layer 2 opposite to the base layer 1 (rear side) in the above range, air is less likely to be trapped between the adhesive layer and the adherend, and interfacial reflection between the adhesive layer and the adherend can be suppressed. As a result, by setting the surface roughness of each of the above three surfaces in the above range, for example, even when the laminated film according to the embodiment is attached to a transparent adherend, excellent transparency can be imparted without impairing transparency.

[0023] The surface roughness of the surface 1a of the base layer 1 opposite to the pressure-sensitive adhesive layer 2 is preferably 0.01 μm or more and 1.40 μm or less, more preferably 0.01 μm or more and 1.30 μm or less; 0.01 μm or more and 1.20 μm or less; 0.01 μm or more and 1.10 μm or less; 0.01 μm or more and 1.00 μm or less; 0.01 μm or more and 0.90 μm or less; 0.01 μm or more and 0.80 μm The smaller the surface roughness, the more preferable it is in the order of 0.01 μm or more and 0.70 μm or less; 0.01 μm or more and 0.60 μm or less; 0.01 μm or more and 0.50 μm or less; 0.01 μm or more and 0.40 μm or less; 0.01 μm or more and 0.30 μm or less; and 0.01 μm or more and 0.20 μm or less, with 0.01 μm or more and 0.15 μm or less being particularly preferable.

[0024] The surface roughness of the surface 1b of the base layer 1 facing the pressure-sensitive adhesive layer 2 is more preferably 0.10 μm or more and 1.10 μm or less, and is more preferably smaller in the following order: 0.01 μm or more and 1.00 μm or less; 0.01 μm or more and 0.90 μm or less; 0.01 μm or more and 0.80 μm or less; 0.01 μm or more and 0.70 μm or less; 0.01 μm or more and 0.60 μm or less; 0.01 μm or more and 0.50 μm or less; 0.01 μm or more and 0.40 μm or less; 0.01 μm or more and 0.30 μm or less; and 0.01 μm or more and 0.20 μm or less, with 0.01 μm or more and 0.15 μm or less being particularly preferred.

[0025] The surface roughness of the surface 2b of the pressure-sensitive adhesive layer 2 opposite the base layer 1 is preferably 0.01 μm or more and 0.35 μm or less, more preferably 0.01 μm or more and 0.30 μm or less; more preferably 0.01 μm or more and 0.25 μm or less, in that order, and particularly preferably 0.01 μm or more and 0.20 μm or less.

[0026] In this specification, the surface roughness refers to the ten-point average roughness (RzJIS), and is a value measured by a method conforming to JIS B0601:2001. The surface roughness can be measured using a shape analysis laser microscope VK-X150 manufactured by KEYENCE Corporation. The surface roughness of the surface 1a of the base layer 1 opposite the adhesive layer 2 can be measured from the front side of the laminated film. The surface roughness of the surface 1b of the base layer 1 opposite the adhesive layer 2 can be measured after dropping isopropyl alcohol (IPA) onto the adhesive layer and wiping it off with a rag after 10 seconds to remove the adhesive. In addition, when removing the adhesive, ethyl acetate or a hydrocarbon solvent may be dropped instead of dropping IPA. When a separator is present, the surface roughness of the surface 2b of the adhesive layer 2 opposite the base layer 1 can be measured by peeling off the separator and then measuring the surface roughness of the exposed adhesive layer.

[0027] The above surface roughness can be measured by the following method. An image is captured under the following conditions, the evaluation length is set to 250 μm, and five roughness curves are obtained by shifting by 20 μm in one direction. Each of the above five roughness curves is analyzed using analysis application software, and the ten-point average roughness (RzJIS) of the five points is calculated. The average value of the three points excluding the highest and lowest values ​​of the surface roughness of the above five points is taken as the surface roughness (RzJIS). <Measurement conditions> Observation application software: VK-H1XV2 Objective lens: 50x Measurement size: Standard (1024 x 768) Analysis application software: VK-H1XM

[0028] The surface roughness of the surface 1a of the substrate layer 1 opposite to the adhesive layer 2 and the surface roughness of the surface 1b of the substrate layer 1 opposite to the adhesive layer 2 can be adjusted by the manufacturing method such as the blending of the resin composition used in the substrate layer, the thickness of the substrate layer, the surface roughness of the calendar roll used in forming the substrate layer, and the procedure of calendar molding. The above-mentioned calendar molding can be formed into a film by passing the resin composition between a pair of calendar rolls, and the surface roughness of one side and the other side of the substrate layer can be made different by adjusting the surface roughness of each calendar roll. In addition, the surface roughness of both sides of the substrate layer can be adjusted by disposing a support sheet on one side of the substrate layer during calendar molding. The surface roughness of the surface 2b of the adhesive layer 2 opposite to the substrate layer 1 can be adjusted by the surface roughness of the separator to which the adhesive composition is applied.

[0029] It is preferable that the base material layer 1 and the pressure-sensitive adhesive layer 2 are in contact with each other. By having the base material layer 1 and the pressure-sensitive adhesive layer 2 in contact with each other, higher transparency can be obtained.

[0030] The haze value of the laminate formed by combining the base layer 1 and the adhesive layer 2 is preferably 3.0% or less. When the haze value of the laminate formed by combining the base layer 1 and the adhesive layer 2 is 3.0% or less, it can give a clear appearance with little turbidity even when attached to a transparent adherend. The haze value is more preferably 2.5% or less, and even more preferably 2.0% or less. The haze value is the haze value of the laminate formed by combining the two layers of the base layer 1 and the adhesive layer 2, and does not include the haze values ​​of other layers such as the separator, the design layer, and the layer disposed between the base layer 1 and the adhesive layer 2. The haze value is a value measured by a method conforming to JIS K 7136:2000. The haze value can be measured using "HazeMeter NDH5000" manufactured by Nippon Denshoku Industries Co., Ltd.

[0031] <Base material layer> The substrate layer is preferably a resin film made of a resin composition. Examples of the resin film include polyvinyl chloride film, polyethylene film, polypropylene film, etc., and among them, polyvinyl chloride film is more preferable because it has high transparency, good elongation, conforms to the surface shape of the adherend, and is difficult to break. The polyvinyl chloride film preferably has a vinyl chloride resin content of 50% by mass or more, more preferably 90% by mass or more, based on 100% by mass of the entire resin components of the film.

[0032] Examples of the polyvinyl chloride include homopolymers of vinyl chloride and copolymers of vinyl chloride and other monomers copolymerizable with vinyl chloride. Examples of the other copolymerizable monomers include vinyl esters such as vinyl acetate and vinyl propionate; olefins such as ethylene, propylene, and styrene; alkyl (meth)acrylate esters such as methyl (meth)acrylate, ethyl (meth)acrylate, and methyl (meth)acrylate; maleic acid diesters such as dibutyl maleate and diethyl maleate; fumaric acid diesters such as dibutyl fumarate and diethyl fumarate; vinyl cyanides such as acrylonitrile and methacrylonitrile; vinyl halides such as vinylidene chloride and vinyl bromide; and vinyl ethers such as methyl vinyl ether and ethyl vinyl ether. These may be used alone or in combination of two or more. In this specification, "(meth)acrylic acid" refers to "at least one of acrylic acid and methacrylic acid".

[0033] The content of the other copolymerizable monomer in the copolymer is usually 50% by mass or less, preferably 10% by mass or less, based on 100% by mass of the total amount of all monomers. Among the polyvinyl chlorides, a homopolymer of vinyl chloride is preferred from the viewpoint of excellent dimensional stability.

[0034] The average degree of polymerization of the polyvinyl chloride is preferably 800 to 1300. In the present invention, the average degree of polymerization of the polyvinyl chloride means the average degree of polymerization measured in accordance with JIS K 6721:1977 "Testing methods for vinyl chloride resins". If the average degree of polymerization exceeds 1300, the elongation of the polyvinyl chloride film may be insufficient. From the viewpoint of obtaining a polyvinyl chloride film with high transparency, the average degree of polymerization of the polyvinyl chloride is more preferably 1100 or less.

[0035] When the base layer is a polyvinyl chloride film, it may further contain a plasticizer. The plasticizer is an additive that imparts flexibility to the polyvinyl chloride film. Examples of the plasticizer include polyester-based plasticizers such as aliphatic ester compounds and alicyclic ester compounds; and phthalic acid-based plasticizers such as di-2-ethylhexyl phthalate (DOP), dibutyl phthalate, dinonyl phthalate, diisononyl phthalate (DINP), and bis(2-ethylhexyl) terephthalate (DOTP).

[0036] The polyvinyl chloride film preferably contains a polyester-based plasticizer because it has good compatibility with polyvinyl chloride. Examples of polyester-based plasticizers include plasticizers containing an aliphatic ester compound and an alicyclic ester compound. Examples of the aliphatic ester compound (non-cyclic aliphatic ester) include adipic acid ester and polyester in which adipic acid and polyalcohol are bonded. Specific examples of the aliphatic ester compound include Adeka Cizer (registered trademark) PN-7535, Adeka Cizer PN-7160, and PN-9302 manufactured by ADEKA Corporation, and Green Cizer BZ-100 manufactured by New Japan Chemical Co., Ltd., etc. Examples of the alicyclic ester compound include cyclohexane-based carboxylate esters. Specific examples of the alicyclic ester compound include HEXAMOLL (registered trademark) DINCH manufactured by BASF, etc. The HEXAMOLL DINCH is a plasticizer containing di-isononyl-cyclohexane-dicarboxylate.

[0037] If the number average molecular weight of the plasticizer is small, the plasticizer is likely to migrate to the adhesive layer, and the laminated film may shrink when stored for a long period of time. From the viewpoint of suppressing the shrinkage of the laminated film, the number average molecular weight of the plasticizer is preferably large, for example, preferably 500 or more, more preferably 2000 or more. The upper limit of the number average molecular weight of the plasticizer may be, for example, 3000. If the number average molecular weight of the plasticizer exceeds 4000, the polyvinyl chloride film becomes hard, and the workability of the film outdoors may be reduced. The more preferable upper limit of the number average molecular weight of the plasticizer is 3000.

[0038] The number average molecular weight Mn of the plasticizer is measured by gel permeation chromatography (GPC) under the following conditions. Device name: HLC-8120 (Tosoh Corporation) Column: G7000HXL 7.8mmID×30cm 1 unit, GMHXL 7.8mmID×30cm 2 units, G2500HXL 7.8mmID×30cm 1 unit (Tosoh Corporation) Sample concentration: Dilute with tetrahydrofuran to 1.5 mg / ml Mobile phase solvent: Tetrahydrofuran Flow rate: 1.0ml / min Column temperature: 40℃

[0039] The content of the plasticizer may be 5 parts by mass or more and 80 parts by mass or less per 100 parts by mass of polyvinyl chloride. If the content is less than 5 parts by mass, the polyvinyl chloride film may become too hard, and if the content is more than 80 parts by mass, the plasticizer may bleed out (float) to the film surface. The more preferred lower limit of the content is 10 parts by mass, the more preferred upper limit is 50 parts by mass, and the even more preferred upper limit is 30 parts by mass.

[0040] The substrate layer may further include a heat stabilizer. Since halogen-containing resins such as polyvinyl chloride are prone to thermal decomposition due to dehydrohalogenation during melt kneading or film formation, a heat stabilizer may be added to suppress deterioration during the processing step. An additive that suppresses deterioration or decomposition during kneading of the resin composition or during film formation is also called a stabilizer, and an additive that suppresses thermal decomposition in particular is also called a heat stabilizer. By suppressing thermal decomposition during the processing step, the transparency of the substrate layer can be increased.

[0041] Examples of the heat stabilizer include those containing phosphite, phosphite, barium / zinc soap, hydrotalcite, diketone compound, zinc stearate, barium stearate, etc. These heat stabilizers may be used alone or in combination of two or more. Examples of the heat stabilizer containing phosphite include AP-614 manufactured by ADEKA CORPORATION. Examples of the heat stabilizer containing phosphite include Adeka STAB 1500 manufactured by ADEKA CORPORATION. Examples of the heat stabilizer containing barium / zinc soap include Adeka STAB AC-258 manufactured by ADEKA CORPORATION. Examples of the heat stabilizer containing hydrotalcite include Magcera 1 manufactured by Kyowa Chemical Industry Co., Ltd.

[0042] The content of the heat stabilizer is preferably 1 part by mass or more and 10 parts by mass or less, more preferably 2 parts by mass or more and 7 parts by mass or less, and even more preferably 3 parts by mass or more and 4 parts by mass or less, relative to 100 parts by mass of the resin component. In this specification, when the base layer is a vinyl chloride film, "relative to 100 parts by mass of the resin component" which is the standard for the content of each component is read as "relative to 100 parts by mass of polyvinyl chloride".

[0043] The substrate layer may contain an ultraviolet absorbing agent. The ultraviolet absorbing agent has the effect of suppressing photodegradation of the resin component by absorbing ultraviolet light that hits the film surface. Examples of the ultraviolet absorbing agent include benzotriazole-based ultraviolet absorbing agents, benzophenone-based ultraviolet absorbing agents, and triazine-based ultraviolet absorbing agents. Examples of the benzotriazole-based ultraviolet absorbing agent include ADK STAB LA-29, LA-24, LA-31RG, LA-32, and LA-36 manufactured by ADEKA CORPORATION. Examples of the benzophenone-based ultraviolet absorbing agent include ADK STAB 1413 manufactured by ADEKA CORPORATION. Examples of the triazine-based ultraviolet absorbing agent include ADK STAB LA-46 and LA-F70 manufactured by ADEKA CORPORATION, and Tinuvin 1600 manufactured by BASF Japan Co., Ltd. In particular, since polyvinyl chloride is particularly prone to photodegradation, it can be suitably used when the substrate layer is a polyvinyl chloride film.

[0044] The content of the ultraviolet absorber is, for example, 0.5 parts by mass or more and 3.0 parts by mass or less with respect to 100 parts by mass of the resin component. If the content exceeds 3.0 parts by mass, the ultraviolet absorber may migrate to the surface of the base layer and bleed out. If bleed-out occurs, the transparency of the base layer and the adhesive properties of the adhesive layer may decrease. The content of the ultraviolet absorber is more preferably 1 part by mass or more, more preferably 1.5 parts by mass or more.

[0045] The substrate layer may contain a hindered amine-based light stabilizer. The hindered amine-based light stabilizer is a compound that contains a hindered amine in its structure and captures (traps) radicals generated by irradiation with light such as ultraviolet light, thereby suppressing deterioration of a film or the like. The hindered amine-based light stabilizer may contain a compound having a structure in which a hydrogen group, an alkyl group, or an alkoxyl group is bonded to a nitrogen atom of a piperidine ring. Furthermore, the hindered amine-based light stabilizer preferably contains a compound having a structure in which an alkoxyl group is bonded to a nitrogen atom of a piperidine ring. Examples of the hindered amine-based light stabilizer include Adeka STAB LA-52, LA-81, LA-77Y, LA-63P, and LA-72 manufactured by ADEKA CORPORATION, and Tinuvin 123 manufactured by BASF Japan Ltd.

[0046] The content of the hindered amine-based light stabilizer is, for example, 0.1 parts by mass or more and 2 parts by mass or less with respect to 100 parts by mass of the resin component. If the content exceeds 2 parts by mass, bleeding out may occur. The more preferable lower limit of the content of the hindered amine-based light stabilizer is 0.2 parts by mass, and the more preferable upper limit is 1 part by mass.

[0047] The substrate layer may further include an epoxy compound. By blending an epoxy compound in the substrate layer, the processability of the substrate layer can be improved. Examples of the epoxy compound include epoxidized soybean oil and epoxy group-containing acrylic resin. Specific examples of epoxidized soybean oil include Adeka Cizer O-130P manufactured by ADEKA CORPORATION. Specific examples of epoxy group-containing acrylic resin include Metablen (registered trademark) P-1901 manufactured by Mitsubishi Chemical Corporation and Marproof (registered trademark) G-0150M manufactured by NOF Corporation.

[0048] The content of the epoxy compound is preferably 0.5 parts by mass or more and 6 parts by mass or less, and more preferably 1 part by mass or more and 4 parts by mass or less, relative to 100 parts by mass of the resin component.

[0049] The substrate layer may contain a colorant such as a pigment or dye within a range that does not impair transparency. When the substrate layer contains a colorant, the content is preferably 0.5 parts by mass or less, and more preferably 0.08 parts by mass or less, per 100 parts by mass of the resin component.

[0050] The substrate layer may contain a processing aid, a plate-out inhibitor, and the like, as required.

[0051] The thickness of the base layer is, for example, 50 μm or more and 300 μm or less. If the thickness is less than 50 μm, the strength may be insufficient and sufficient durability may not be obtained. If the thickness exceeds 300 μm, the stiffness may be strong and it may be difficult to attach to the adherend. The preferable lower limit of the thickness is 60 μm, and the preferable upper limit is 160 μm.

[0052] The method for producing the substrate layer includes, for example, a method in which materials are mixed (melted and kneaded) while being heated using a Banbury mixer or the like to obtain a resin composition, and then the resin composition is formed into a film. As the film formation method, a conventionally known molding method such as calendar molding, extrusion molding, injection molding, etc. can be used, but calendar molding is preferable because it can produce even a thin film with excellent thickness accuracy. The molding method of calendar molding will be described later.

[0053] <Adhesive layer> The pressure-sensitive adhesive layer is not particularly limited as long as it has an adhesive function (pressure-sensitive adhesiveness), and examples thereof include those containing adhesives such as acrylic adhesives, rubber adhesives, and silicone adhesives. Among them, acrylic adhesives are preferably used because they are excellent in transparency, adhesiveness, processability, heat aging resistance, weather resistance, and the like, and are relatively inexpensive. Examples of acrylic adhesives include SK Dyne 2006HE and SK Dyne 1506A manufactured by Soken Chemical & Engineering Co., Ltd. These may be used alone or in combination of two or more types.

[0054] The pressure-sensitive adhesive layer may further contain a curing agent such as an epoxy-based curing agent, the above-mentioned ultraviolet absorber, a hindered amine-based light stabilizer, and a solvent such as toluene.

[0055] The content of the curing agent is, for example, 0.1 parts by mass or more and 2 parts by mass or less with respect to 100 parts by mass of the resin component. The content of the ultraviolet absorber is, for example, 0.1 parts by mass or more and 2 parts by mass or less with respect to 100 parts by mass of the resin component. The content of the hindered amine-based light stabilizer is, for example, 0.1 parts by mass or more and 2 parts by mass or less with respect to 100 parts by mass of the resin component.

[0056] The thickness of the pressure-sensitive adhesive layer is preferably from 10 to 60 μm, and more preferably from 20 to 50 μm.

[0057] <Separator> As shown in FIG. 1, the laminated film 10 according to the embodiment may further have a separator 3 on the side of the adhesive layer 2 opposite to the base layer 1. By disposing the separator, the surface of the adhesive layer can be protected. In addition, by forming the adhesive layer by applying an adhesive composition onto the separator, the surface roughness of the adhesive layer can be adjusted by the uneven shape of the separator surface. The separator is peeled off when in use.

[0058] The surface roughness of the separator on the pressure-sensitive adhesive layer side is preferably 0.02 μm or more and 0.45 μm or less, more preferably 0.02 μm or more and 0.40 μm or less; 0.02 μm or more and 0.35 μm or less; 0.02 μm or more and 0.30 μm or less, and particularly preferably 0.02 μm or more and 0.27 μm or less. The surface of the separator on the pressure-sensitive adhesive layer side is preferably subjected to a release treatment. The method of the release treatment is not particularly limited, and a known method can be used.

[0059] The separator is preferably a resin sheet, since it is easy to impart an uneven shape to the separator and to maintain the uneven shape. For example, polyethylene terephthalate (PET) is used.

[0060] As shown in Fig. 1, the surface 3b of the separator 3 opposite the adhesive layer 2 is preferably matte-treated. Since the surface 1a of the base layer 1 opposite the adhesive layer 2 (front side) of the laminated film 10 is highly smooth, when the laminated film 10 is wound up in a roll and stored, the films tend to stick to each other. By matte-treating the surface 3b of the base layer 1 opposite the adhesive layer 2 of the separator 3 (rear side), the films can be prevented from sticking to each other even when the laminated film 10 is wound up in a roll and stored.

[0061] The matte treatment may be performed by applying a matting agent to the surface 3b of the separator 3 or by applying a graining process to the surface 3b of the separator 3. Examples of the matting agent include those containing urethane resin, silica, acrylic resin, etc.

[0062] <Design layer> Fig. 2 is a cross-sectional view showing a schematic diagram of another example of the laminated film according to the embodiment. As shown in Fig. 2, the laminated film according to the embodiment may further have a design layer 4 on the surface of the base layer 1 opposite to the pressure-sensitive adhesive layer 2 side.

[0063] The design layer may be disposed over the entire base layer 1, or may be disposed so as to overlap a portion of the base layer 1. Since the laminate film according to the embodiment is highly transparent, by disposing the design layer so as to overlap a portion of the base layer 1, the observer can see the letters, patterns, etc. of the design layer, while also being able to see the background of the opposite side of the transparent adherend through the laminate film in the portion where the design layer is not formed.

[0064] The design layer may be a printed layer, and may be printed by, for example, inkjet printing, gravure printing, screen printing, rotary screen printing, flexographic printing, offset printing, electrostatic printing, etc. Also, a colored film or the like may be attached.

[0065] <Adherend> 3 is a cross-sectional view showing a schematic state in which the laminated film according to the embodiment is attached to an adherend. The laminated film 10 can be used by being attached to an adherend 20 via a pressure-sensitive adhesive layer 2. The laminated film 10 is preferably a film for use as a printing base, and can be suitably used, for example, for advertising signboards.

[0066] Examples of the material of the adherend include resins such as polycarbonate resins, acrylic resins, and styrene resins, acrylonitrile-butadiene-styrene copolymers (ABS resins), metals such as iron, copper, and aluminum, and alloys. Since the laminated film 10 has excellent transparency, it is particularly preferable to attach it to a transparent adherend such as glass or resin. The transparent adherend has a total light transmittance of 80% or more as measured by a method in accordance with JIS K 7361-1:1997.

[0067] <Laminated film manufacturing method> The following manufacturing method is exemplified as a manufacturing method of the laminated film according to the embodiment, but is not limited to the following method. Another embodiment of the present invention is a manufacturing method of the laminated film according to the embodiment, which includes a base layer forming step of forming a base layer having a first surface on which the support sheet is laminated and a second surface in contact with the surface of the first calendar roll, a separator having a surface roughness of 0.01 μm or more and 0.45 μm or less, a separator having a surface roughness of 0.01 μm or more and 0.45 μm or less, and a lamination step of laminating the surface of the adhesive layer opposite to the surface in contact with the separator on the second surface of the base layer. With the above manufacturing method, a laminated film that can impart excellent transparency even when attached to a transparent adherend can be produced.

[0068] The base layer of the laminated film of the present embodiment is preferably formed by calendar molding using a pair of calendar rolls. The surface roughness of one of the pair of calendar rolls (first calendar roll) is set to 0.01 μm or more and 1.30 μm or less, and an adhesive layer is laminated on the surface (second surface) of the base layer that is in contact with the first calendar roll, so that the surface roughness of the adhesive layer side surface of the base layer of the obtained laminated film can be set to 0.01 μm or more and 1.20 μm or less. The surface roughness of the first calendar roll is more preferably 0.01 μm or more and 0.70 μm or less. The surface roughness of the second calendar roll is not particularly limited, and may be rougher than 1.60 μm.

[0069] The surface roughness of the calendar roll can be measured by the following method. Silicone resin is applied to the surface of the calendar roll, and dried at 23°C for 5 minutes. The silicone resin is then peeled off from the surface of the calendar roll, and the surface roughness of the silicone resin to which the surface shape of the calendar roll is transferred is measured. For example, the silicone resin can be applied using a RepliSet-GF1 manufactured by Struers SAS. The surface roughness of the silicone resin is measured by the ten-point average roughness (RzJIS) measurement method in accordance with the above-mentioned JIS B0601:2001.

[0070] Alternatively, a support sheet having a surface roughness of 0.01 μm or more and 1.60 μm or less may be disposed between the first and second calendar rolls so as to contact the second calendar roll to form a base layer, and an adhesive layer may be laminated on the surface (second surface) opposite to the surface (first surface) of the base layer on which the support sheet is laminated, thereby making it possible to obtain a laminate film having a surface roughness of 0.01 μm or more and 1.50 μm or less on the surface opposite to the adhesive layer of the base layer. The surface roughness of the support sheet is more preferably 0.01 μm or more and 0.40 μm or less.

[0071] The support sheet is a sheet that is peeled off when the laminated film is used. By forming a base layer by disposing a support sheet with a predetermined surface roughness between the first calendar roll and the second calendar roll so as to contact the second calendar roll, it is possible to prevent the base layer from sticking to the second calendar roll and to make the first surface of the base layer that contacts the support sheet have a desired surface roughness. In the base layer forming step, it is preferable to form the base layer while sandwiching the support sheet between the first and second calendar rolls, and the support sheet is laminated on the first surface of the base layer. In the calendar molding, the film (base layer) after passing through the calendar roll is wound into a roll, and then the base layer is laminated with the adhesive layer while being unwound. Therefore, if the surface roughness of both the first and second calendar rolls is 0.01 μm or more and 1.30 μm or less, the base layer sticks to both calendar rolls, making it difficult to wind it into a roll. By positioning the support sheet as described above, the base layer separates from the second calendar roll with the support sheet still attached, and the base layer can be wound into a roll using the support sheet as a support for the base layer.

[0072] The support sheet is preferably a sheet having heat resistance such that it does not deform at the temperature during lamination (50°C to 70°C), rigidity that allows it to serve as a support for the base layer, and flexibility that allows it to be wound into a roll. The support sheet is preferably a resin sheet, such as polyethylene terephthalate (PET). The thickness of the support sheet is preferably, for example, 10 μm or more and 50 μm or less.

[0073] No adhesive layer or the like is disposed on the surface of the support sheet that contacts the base layer. In addition, it is preferable that the surface of the support sheet that contacts the base layer is not subjected to a release treatment or a matte treatment. On the other hand, the surface of the support sheet that contacts the base layer may be corona treated.

[0074] In the pressure-sensitive adhesive layer forming step, a pressure-sensitive adhesive layer is formed on the surface of a separator having a surface roughness of 0.01 μm or more and 0.45 μm or less, and the surface of the pressure-sensitive adhesive layer opposite to the surface in contact with the separator is laminated on the second surface of the base layer, so that the surface roughness of the pressure-sensitive adhesive layer opposite to the base layer of the resulting laminated film can be made 0.01 μm or more and 0.40 μm or less. The surface roughness of the separator is more preferably 0.01 μm or more and 0.30 μm or less.

[0075] In the lamination step, the support sheet and the base material layer are preferably thermally laminated. Thermal lamination is an adhesion method in which a plurality of films or sheets are passed between heated calendar rolls to be bonded. For example, the calendar rolls are preferably heated to 50°C to 70°C. The base material layer may be heated with a preheating calendar roll separate from the first and second calendar rolls before being bonded.

[0076] In the base layer forming step, the base layer may be formed by passing the resin composition between the first and second calendar rolls, or an already formed film (also called a precursor layer of the base layer) may be passed between the first and second calendar rolls. For example, the resin composition may be formed into a sheet-like film using a film-forming calendar roll, and then passed between the first and second calendar rolls.

[0077] The manufacturing method of the laminated film according to this embodiment may include, prior to the base layer forming step, a step of passing between the first calendar roll and the second calendar roll to form a precursor layer for the base layer, in which the precursor layer is inverted and positioned so that the surface in contact with the surface of the first calendar roll faces the second calendar roll and the surface in contact with the surface of the second calendar roll faces the first calendar roll, and the support sheet may be positioned between the second calendar roll and the surface of the precursor layer in contact with the surface of the first calendar roll.

[0078] The precursor layer is inverted, the surface in contact with the surface of the first calendar roll is brought into contact with the support sheet, and the second calendar roll is applied from the support sheet side to thermally laminate the precursor layer and the support sheet, thereby preventing air from being trapped between the precursor layer and the support sheet. If air is trapped between the precursor layer and the support sheet, it becomes difficult to transfer the surface shape of the support sheet to the surface of the precursor layer, and the surface roughness of the surface of the base layer of the laminated film opposite to the adhesive layer may exceed 1.50 μm. The first calendar roll is preferably a metal roll such as iron, and the second calendar roll is preferably a resin roll such as silicon. In particular, by making the second calendar roll a resin roll such as silicon, it is possible to effectively prevent air from being trapped between the precursor layer and the support sheet.

[0079] 4A to 4C are schematic diagrams illustrating the steps of the method for producing a laminated film according to an embodiment. As shown in FIG. 4A, a step of passing a resin composition or a film between a first calendar roll 101 and a second calendar roll 102 to form a precursor layer 100 of the substrate layer may be included. In FIG. 4A to FIG. 4C, in the step of forming the precursor layer 100 of FIG. 4A, the surface of the precursor layer 100 that contacts the surface of the first calendar roll 101 is represented as 100a, and the surface of the precursor layer 100 that contacts the surface of the second calendar roll 102 is represented as 100b. As shown in FIG. 4B, the precursor layer 100 is inverted and arranged so that the surface 100a of the precursor layer 100 faces the second calendar roll 102 and the surface 100b of the precursor layer 100 faces the first calendar roll 101. At this time, the support sheet 30 is disposed between the second calendar roll 102 and the surface 100a of the precursor layer 100 so that the surface of the support sheet having a surface roughness of 0.01 μm or more and 1.60 μm or less is in contact with the surface 100a of the precursor layer 100, and the precursor layer 100 and the support sheet 30 are sandwiched between the first and second calendar rolls and calendared to form the base material layer 1 to which the desired surface roughness has been transferred. In this specification, the film to which the desired surface roughness has been transferred to the surface of the precursor layer 100 is referred to as the base material layer 1.

[0080] The surface 100a of the precursor layer 100 corresponds to the first surface of the base material layer, and the first surface of the base material layer corresponds to surface 1a on the opposite side (front side) of the adhesive layer of the base material layer in FIG. 1. The surface 100b of the precursor layer 100 corresponds to the second surface of the base material layer, and the second surface of the base material layer corresponds to surface 1b on the adhesive layer side (back side) of the base material layer in FIG. 1. The surface of the adhesive layer on which the separator is disposed corresponds to surface 2b on the opposite side (back side) of the adhesive layer of the base material layer in FIG. 1. The first surface of the separator corresponds to the surface on the adhesive layer side of the separator.

[0081] The surface roughness of the surface 1b of the base layer 1 on the side of the adhesive layer 2 before the adhesive layer 2 is disposed is preferably 0.01 μm or more and 2.40 μm or less, and is preferably 0.01 μm or more and 2.30 μm or less; 0.01 μm or more and 2.20 μm or less; 0.01 μm or more and 2.10 μm or less; 0.01 μm or more and 2.00 μm or less; 0.01 μm or more and 1.90 μm or less; 0.01 μm or more and 1.80 μm or less; 0.01 μm or more and 1.70 μm or less; 0.01 μm or more and 1.60 μm or less; 0.01 μm or more and 1.50 μm or less; 0.01 μm or more and 1.40 μm or less. The smaller the surface roughness, the more preferable it is in the following order: 0.01 μm or more, 1.30 μm or less; 0.01 μm or more, 1.20 μm or less; 0.01 μm or more, 1.10 μm or more; 0.01 μm or more, 1.00 μm or less; 0.01 μm or more, 0.90 μm or less; 0.01 μm or more, 0.80 μm or less; 0.01 μm or more, 0.70 μm or more; 0.01 μm or more, 0.60 μm or less; 0.01 μm or more, 0.50 μm or less; 0.01 μm or more, 0.40 μm or less; and 0.01 μm or more, 0.30 μm or less, with 0.01 μm or more and 0.20 μm or less being particularly preferable.

[0082] The surface roughness of the surface 1a opposite to the surface 1b of the base material layer 1 before the pressure-sensitive adhesive layer 2 is preferably 0.01 μm or more and 1.90 μm or less, more preferably 0.01 μm or more and 1.80 μm or less; 0.01 μm or more and 1.70 μm or less; 0.01 μm or more and 1.60 μm or less; 0.01 μm or more and 1.50 μm or less; 0.01 μm or more and 1.40 μm or less; 0.01 μm or more and 1.30 μm or less; 0.01 μm or more and 1.20 μm or less; 0.01 μm or less The smaller the surface roughness, the more preferable it is in the following order: 1.10 μm or less; 0.01 μm or more and 1.00 μm or less; 0.01 μm or more and 0.90 μm or less; 0.01 μm or more and 0.80 μm or less; 0.01 μm or more and 0.70 μm or less; 0.01 μm or more and 0.60 μm or less; 0.01 μm or more and 0.50 μm or less; 0.01 μm or more and 0.40 μm or less; and 0.01 μm or more and 0.30 μm or less, with 0.01 μm or more and 0.20 μm or less being particularly preferable.

[0083] When the manufacturing method of the laminated film according to this embodiment includes a step of forming a precursor layer of the base layer, the surface roughness of the second calendar roll is preferably 4.0 μm or more and 6.0 μm or less, from the viewpoint of preventing the precursor layer from sticking to the second calendar roll.

[0084] By laminating the surface of the pressure-sensitive adhesive layer opposite the surface in contact with the separator onto the second surface of the base material layer, a laminate is obtained in which a support sheet 30, a base material layer 1, a pressure-sensitive adhesive layer 2, and a separator 3 are laminated in this order, as shown in Figure 4C, and by peeling off the support sheet 30, a laminate film 10 according to the embodiment is obtained.

[0085] The method for producing the laminated film may further include a step of forming a design layer on the surface of the base layer 1 opposite the pressure-sensitive adhesive layer 2 side.

[0086] The base layer, the pressure-sensitive adhesive layer, the separator, and the design layer may each have the same configuration as described above for the laminate film. EXAMPLES

[0087] The present invention will be described in more detail below with reference to examples, but the present invention is not limited to these examples.

[0088] The materials used in the base layers of the following Examples and Comparative Examples are shown in Table 1 below.

[0089] [Table 1]

[0090] The materials used in the pressure-sensitive adhesive layers of Examples 1 to 6 and Comparative Examples 1 to 3 are shown in Table 2 below, and the materials used in the pressure-sensitive adhesive layers of Example 7 are shown in Table 3 below. In Tables 2 and 3, "%" means "% by mass."

[0091] [Table 2]

[0092] [Table 3]

[0093] Formulations 1 to 3 of the polyvinyl chloride resin compositions used in the base layers of the following Examples and Comparative Examples are shown in the following Tables 4 to 6, respectively. The components shown in Tables 4 to 6 correspond to the components shown in Table 1.

[0094] [Table 4]

[0095] [Table 5]

[0096] [Table 6]

[0097] Example 1 (Preparation of precursor layer of substrate layer) The materials shown in Table 1 were mixed in the formulation 1 shown in Table 4 to prepare a polyvinyl chloride resin composition, which was then melt-kneaded with a twin-screw roll. Under the following calendering conditions, the polyvinyl chloride resin composition was passed between a pair of film-forming calender rolls to form a polyvinyl chloride (PVC) film, and immediately thereafter, the PVC film was passed between a first calender roll and a second calender roll to produce a PVC film (precursor layer) having a thickness of 60 μm. <Configuration of the first and second calendar rolls> First calendar roll: Iron roll, surface roughness: RzJIS=0.53μm Second calendar roll: Silicon roll, surface roughness: RzJIS=11.4μm <Calendar molding conditions> Film-forming calendar roll temperature: 185°C (steam) Film-forming calendar roll speed: 10 m / min First calendar roll temperature: 65°C (hot water) First calendar roll speed: 27m / min Second calendar roll temperature, speed conditions: None Pressure: 0.3MPa The pressure setting value applied between the rolls can be found by sandwiching pressure-sensitive paper (Prescale LLLW manufactured by Fuji Film Corporation) between the rolls, applying force perpendicular to the pressure-sensitive paper from the roll side, reading the area where the pressure-sensitive paper changes color, and dividing the force applied to the roll by the read area.

[0098] (Preparation of base layer) While preheating the PVC film (precursor layer) obtained above to 150 ° C. with a preheating calendar roll, the PVC film was inverted so that the surface of the PVC film that had contacted the first calendar roll in the above process was the second calendar roll side, and the surface of the PVC film that had contacted the second calendar roll was the first calendar roll side, and then, while sandwiching a support sheet between the second calendar roll and the PVC film, the PVC film and the support sheet were passed between the first calendar roll and the second calendar roll, and heat laminated at 150 ° C. and a pressure of 0.5 MPa to obtain a laminate of the PVC film (base layer) and the support sheet. As the support sheet, a PET film (E5107 manufactured by Toyobo Co., Ltd., thickness 25 μm) with a surface roughness RzJIS of 0.27 μm was used. One side of the support sheet was corona-treated, and the corona-treated side was attached to the PVC film side to produce a laminate of the base layer and the support sheet. <Calendar molding conditions> Preheating calendar roll temperature: 150℃ (steam) Preheat time: 15 seconds Preheating calendar roll speed: 9m / min First calendar roll temperature: 60°C (hot water) First calendar roll speed: 10m / min Second calendar roll temperature, speed conditions: None

[0099] (Adhesive layer) A polyethylene terephthalate (PET) sheet having a surface roughness shown in Table 7 below was prepared as a separator, and one of the surfaces was subjected to a release treatment using a silicon-based release agent, and the other surface was subjected to a matte treatment by coating with a matting agent containing a urethane resin. An adhesive composition prepared according to the formulation shown in Table 2 was coated on the release-treated surface of the separator to form an adhesive layer with a dry thickness of 20 μm.

[0100] (Laminated film) The surface of the PVC film (base layer) opposite the surface on which the support sheet was placed was bonded to the surface of the pressure-sensitive adhesive layer opposite the separator, and the support sheet was peeled off from the PVC film to produce the laminated film of Example 1.

[0101] (Examples 2 to 6, Comparative Example 1) In Examples 2 to 6 and Comparative Example 1, the formulation of the polyvinyl chloride resin composition was either one of Formulations 1 to 3, and the thickness of the PVC film was changed as shown in Tables 7 and 8 below, as shown in Tables 7 and 8 below. As the separator, in Examples 2 to 6, a PET sheet was used in which the surface roughness of the side to be subjected to release treatment was changed as shown in Table 7 below, and in Comparative Example 1, a release paper having the surface roughness shown in Table 8 below was used.

[0102] Except for the above configuration, the precursor layer for the pressure-sensitive adhesive layer and the base material layer were prepared in the same manner as in Example 1, and the precursor layer and a support sheet were laminated to prepare a laminate of the base material layer and the support sheet. After the base material layer and the pressure-sensitive adhesive layer were bonded together, the support sheet was peeled off to prepare each of the laminate films of Examples 2 to 6 and Comparative Example 1.

[0103] Example 7 As a separator, a PET sheet having a surface roughness shown in Table 7 below was prepared, and the one side was subjected to a release treatment using a silicon-based release agent, and the other side was subjected to a matte treatment by coating with a matte agent containing a urethane resin. A pressure-sensitive adhesive composition (urethane-based pressure-sensitive adhesive composition) prepared with the formulation shown in Table 3 was coated on the release-treated surface of the separator, and a pressure-sensitive adhesive layer was formed so that the dry thickness was 20 μm. Except for the configuration of this pressure-sensitive adhesive layer, precursor layers of the pressure-sensitive adhesive layer and the base material layer were prepared in the same manner as in Example 1, and the precursor layer and the support sheet were laminated to prepare a laminate of the base material layer and the support sheet, and the base material layer and the pressure-sensitive adhesive layer were bonded together, and the support sheet was peeled off to prepare the laminated film of Example 7.

[0104] (Comparative Examples 2 and 3) As shown in Table 8 below, the base layers of Comparative Examples 2 and 3 were prepared using the same method as the manufacturing method of the precursor layer of Example 1, with the polyvinyl chloride resin composition formulation 1. That is, in Comparative Examples 2 and 3, the PVC film was formed using the film-forming calendar roll shown in Example 1, and immediately after that, the PVC film was passed between the first calendar roll and the second calendar roll as the base layer. Comparative Examples 2 and 3 do not include a step of disposing a support sheet between the first calendar roll and the second calendar roll and thermally laminating the PVC film and the support sheet.

[0105] Except for changing the surface roughness of the release-treated side of the PET sheet as shown in Table 8 below, an adhesive layer was formed in the same manner as in Example 1, and the side of each PVC film that had come into contact with the second calendar roll was bonded to the side of the adhesive layer opposite the separator to produce laminate films for Comparative Examples 2 and 3.

[0106] (Surface roughness measurement) The laminate films of the Examples and Comparative Examples were allowed to stand for 30 minutes under conditions of room temperature of 23°C and humidity of 50%, and then cut into 30 mm squares. The surface roughness of the surface of the base layer opposite the adhesive layer (front side), the surface of the base layer facing the adhesive layer (back side), and the surface of the adhesive layer opposite the base layer (separator side) were measured using the method described below, and the results are summarized in Tables 7 and 8 below.

[0107] The surface roughness of the front surface of the base layer was measured from the front side of the laminate film of each of the Examples and Comparative Examples both before and after the adhesive layer was attached.

[0108] The surface roughness of the adhesive layer side (rear side) of the base layer before the adhesive layer was attached was measured in the state where the support sheet and base layer were laminated for Examples 1 to 7 and Comparative Example 1, and in the state where only the base layer was attached for Comparative Examples 2 and 3.

[0109] The surface roughness of the adhesive layer side (back side) of the base layer after the adhesive layer was attached was measured by peeling off the separator, dropping isopropyl alcohol (IPA) onto the adhesive layer, wiping it off with a rag after 10 seconds to remove the adhesive, drying for 30 minutes at room temperature of 23° C. and humidity of 50%, and then measuring the surface roughness. Note that, for the laminated film obtained in Example 7, one hour after the adhesive layer was formed, the separator was peeled off from the laminated film, IPA was dropped onto the adhesive layer, wiping it off with a rag after 10 seconds to remove the adhesive, drying for 30 minutes at room temperature of 23° C. and humidity of 50%, and then measuring the surface roughness.

[0110] The surface roughness of the pressure-sensitive adhesive layer on the side opposite to the base layer (the separator side) was measured by peeling off the separator and then measuring the surface roughness of the exposed pressure-sensitive adhesive layer.

[0111] The surface roughness is the ten-point average roughness (RzJIS), and is a value measured by a method conforming to JIS B0601:2001. A shape analysis laser microscope VK-X150 manufactured by KEYENCE was used as a measuring device, and the surface roughness was calculated under the following measurement conditions. Images were captured under the following conditions, and the evaluation length was set to 250 μm, and five roughness curves were obtained by shifting by 20 μm in one direction. Each of the five roughness curves was analyzed by an analysis application software, and the ten-point average roughness (RzJIS) of the five points was calculated. The average value of the three points excluding the highest and lowest values ​​of the surface roughness of the five points was listed in Tables 7 and 8 as the surface roughness (RzJIS) of each of the examples and comparative examples. <Measurement conditions> Observation application software: VK-H1XV2 Objective lens: 50x Measurement size: Standard (1024 x 768) Analysis application software: VK-H1XM

[0112] (Haze value measurement) For the examples and comparative examples, the haze value of the combined base layer and adhesive layer was measured by the following method, and the results are summarized in Tables 7 and 8 below. The laminated films of the examples and comparative examples were left to stand at 23°C for 1 hour. Then, for each of the examples and comparative examples, three samples cut into 30 mm squares were prepared. The surface of the base layer of each sample opposite the adhesive layer (front side) was wiped with a cloth soaked in IPA to remove dirt, and if a liquid film of IPA was visible on the base side when wiped, it was confirmed that the liquid film had dried at room temperature and was no longer visible, and then the separator was peeled off from the adhesive layer and immediately set in a measuring instrument to measure the haze value of each sample. The haze value was measured using a "HazeMeter NDH5000" manufactured by Nippon Denshoku Industries Co., Ltd. in a method conforming to JIS K 7136:2000. Light was irradiated from the LED light source of the measuring instrument to the film for about 7 seconds, and the haze value was calculated from the measured transmittance. For each of the examples and comparative examples, the average value of the haze values ​​of three samples was taken as the haze value of each of the examples and comparative examples.

[0113] (Transparency assessment) Each laminate film of Examples 1 to 5, 7 and Comparative Examples 1 to 3 was cut into a 100 mm square and attached to an acrylic plate (Kuraray Co., Ltd., COMO GLASS) having a thickness of 1 mm. FIG. 5 is a schematic diagram illustrating a method for testing the transparency of the laminate film. After 30 minutes, as shown in FIG. 5, a monitor was placed at a position 30 cm away from the side of the acrylic plate opposite to the side where the laminate film was attached, and the character "a" was displayed in black with a font size of 480 on a white monitor screen. The character "a" displayed on the monitor was visually observed from a position 30 cm away from the laminate film on the opposite side of the monitor. The visibility of the characters was evaluated based on the following criteria as to whether the characters looked whitish and whether the outer edges of the characters were blurred, compared to when the characters were observed displayed on a monitor without the laminated film or acrylic plate in place, and the results are shown in Tables 7 and 8 below. 〇: The characters do not look whitish. The outer edges of the characters are not blurred (they have straight lines). △: The characters do not look whitish. The outer edges of the characters are blurred. ×: Characters look whitish. The outer edges of the characters are not blurred (they have straight lines). ××: The displayed characters are unrecognizable.

[0114] The transparency of the laminated film of Example 6 was evaluated in the same manner as described above (evaluation of transparency), except that a 3 mm thick glass plate (manufactured by AGC Inc.) was used instead of the 1 mm thick acrylic plate. Here, the "acrylic plate" in FIG. 5 is replaced with "glass plate." The results are shown in Table 7 below.

[0115] (Evaluation of dimensional stability) A roll-shaped sample with a width of 1370 mm was prepared for each of Examples 1 to 5 and 7 and Comparative Examples 1 to 3. Each roll-shaped sample was unfolded, and a design layer with a width of 1200 mm and a length of 100 mm was printed on the surface of each base layer opposite the adhesive layer under the following conditions, and then dried at room temperature for 24 hours. <Printing conditions> Printer: Mimaki Engineering, JV-300 Printing method: Inkjet Ink type: Solvent-based ink (SS21 ink) Injection density: 400% (cyan 100%, magenta 100%, yellow 100%, black 100%) Number of coats: 2 The above-mentioned jetting density values ​​were determined by setting the jetting density values ​​on a computer using the application provided with the printer (JV-300).

[0116] A laminate film was attached to the surface of the design layer of each sample. Then, the separator was peeled off from the adhesive layer of each sample, and the adhesive layer was attached to a 3 cm thick, 50 mm square acrylic plate (Kuraray Co., Ltd., COMO GLASS). The laminate film of Example 1 (without a printed layer) was used as the laminate film. After leaving it at room temperature for 24 hours, a 40 mm cross cut was made in each sample from the laminate film side to a depth reaching the acrylic plate using a cutter, and the sample was left in an oven set at 80 ° C for 168 hours. The sample was taken out, and after 30 minutes at room temperature, the width of the sample opening at the cross cut part and the peeling state of the sample from the acrylic plate were visually evaluated. ○: The opening of the sample (laminated film) was less than 1 mm △: The opening of the sample (laminated film) was 1 mm or more. ×: The sample (laminated film) peeled off from the acrylic plate.

[0117] The dimensional stability of the laminated film of Example 6 was evaluated in the same manner as described above (evaluation of dimensional stability), except that a 3 cm thick, 50 mm square glass plate (manufactured by AGC Inc.) was used instead of the 3 cm thick, 50 mm square acrylic plate. The results are shown in Table 7 below.

[0118] [Table 7]

[0119] [Table 8] [Explanation of symbols]

[0120] 1: Base material layer 2: Adhesive layer 1a, 1b, 2b: Surface 3: Separator 3b: Surface 4: Design layer 10: Laminated film 20: Adherent 30: Support sheet 100: Precursor layer of the base layer 100a, 100b: Surface 101: First calendar roll 102: Second calendar roll

Claims

1. The adhesive layer includes a base layer and a pressure-sensitive adhesive layer. The surface roughness of the surface of the base layer opposite to the pressure-sensitive adhesive layer is 0.01 μm or more and 1.50 μm or less, The surface roughness of the surface of the base layer facing the pressure-sensitive adhesive layer is 0.01 μm or more and 1.20 μm or less, A laminate film, wherein the surface roughness of the pressure-sensitive adhesive layer on the side opposite to the base layer is 0.01 μm or more and 0.40 μm or less.

2. The laminate film according to claim 1 , wherein the base layer is a polyvinyl chloride film.

3. The laminate film according to claim 2 , wherein the polyvinyl chloride film contains a polyester-based plasticizer.

4. The laminate film according to claim 1 , wherein the base layer and the pressure-sensitive adhesive layer are in contact with each other.

5. The laminate film according to claim 1 , further comprising a separator on the opposite side of the pressure-sensitive adhesive layer to the base layer.

6. The laminated film according to claim 5 , wherein the surface roughness of the separator on the pressure-sensitive adhesive layer side is 0.01 μm or more and 0.45 μm or less.

7. The laminate film according to claim 5 , wherein the surface of the separator opposite to the pressure-sensitive adhesive layer is matte-treated.

8. The laminate film according to claim 1 , which is a printing base film.

9. The laminate film according to claim 8 , further comprising a design layer on the side of the base layer opposite to the pressure-sensitive adhesive layer.

10. The laminate film according to claim 1 , wherein a haze value of a laminate including the base layer and the pressure-sensitive adhesive layer is 3.0% or less.

11. a base layer forming step of disposing a support sheet having a surface roughness of 0.01 μm or more and 1.60 μm or less between a first calendar roll having a surface roughness of 0.01 μm or more and 1.30 μm or less and a second calendar roll so as to be in contact with the second calendar roll, and forming a base layer having a first surface on which the support sheet is laminated and a second surface in contact with the surface of the first calendar roll; a pressure-sensitive adhesive layer forming step of forming a pressure-sensitive adhesive layer on a surface of a separator having a surface roughness of 0.01 μm or more and 0.45 μm or less; a lamination step of laminating a surface of the pressure-sensitive adhesive layer opposite to a surface in contact with the separator onto the second surface of the base layer.

12. Prior to the base layer forming step, a step of passing the material between the first calendar roll and the second calendar roll to form a precursor layer of the base layer is included, The precursor layer is inverted and disposed so that the surface in contact with the surface of the first calender roll faces the second calender roll, and the surface in contact with the surface of the second calender roll faces the first calender roll; The method for producing a laminated film according to claim 11 , wherein the support sheet is disposed between the second calendar roll and the surface of the precursor layer that is in contact with the surface of the first calendar roll.

Images