Adhesive film and method for manufacturing adhesive film

Abstract

To provide an adhesive film in which air bubbles hardly enter between an adhesive layer and a base material even when the adhesive film is stuck to the base material, and a mark of an uneven structure on a surface of the adhesive layer is hardly visually recognized when observed from the base material side.SOLUTION: The adhesive film 10 has a resin film 1 and an adhesive layer 2, and the surface of the adhesive layer opposite to the resin film side has an arithmetic average roughness of 3.5 μm or more and 14.0 μm or less, and a maximum height of 20.0 μm or more and 75.0 μm or less.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The following disclosure relates to adhesive films and methods for manufacturing adhesive films. [Background technology]

[0002] BACKGROUND ART Conventionally, adhesive films have been applied to substrates to impart designs such as colors, patterns, designs, and letters to the substrates, or to protect the surfaces of the substrates. For example, Patent Document 1 discloses a pressure-sensitive adhesive sheet having, on a substrate or release liner, a resin layer comprising a resin portion (X) containing a hydrocarbon resin having carbon atoms in the main chain of its constituent units as a main component, and a particle portion (Y) consisting of fine particles containing silica particles, at least a surface (α) of the resin layer opposite to the side on which the substrate or release liner is provided, which has adhesiveness, and the resin layer is composed of a multilayer structure having, in order from the surface (α) side in the thickness direction, a layer (Xα) and a layer (Y1), and when the intensity ratio [Si / C] of the peak intensity (Si) derived from silicon atoms to the peak intensity (C) derived from carbon atoms is measured in the thickness direction from the surface (α) side of the resin layer using an energy dispersive X-ray analyzer, the intensity ratio in layer (Xα) is less than 0.10 and the intensity ratio in layer (Y1) is 0.10 or more, and irregular recesses are present on the surface (α). [Prior art documents] [Patent documents]

[0003] [Patent Document 1] International Publication No. 2015 / 152350 Summary of the Invention [Problem to be solved by the invention]

[0004] A common method for applying a design to a substrate by attaching an adhesive film is to attach the adhesive film to the front side of the substrate. However, this method may not provide sufficient gloss or a sense of depth, so a method of attaching the adhesive film to the back side of the substrate has been considered. Conventionally, when attaching an adhesive film to a substrate, air entrapment, in which air bubbles are trapped between the adhesive layer of the adhesive film and the substrate, has occurred. According to the inventors' investigations, particularly when the substrate is transparent and the adhesive film is attached to the back side of the transparent substrate, air entrapment bubbles and the surface shape of the adhesive layer are visible when the decorated molded product is observed from the front side of the transparent substrate, resulting in a poor appearance of the decorated molded product with the adhesive film attached to the substrate.

[0005] The present invention has been made in consideration of the above-mentioned current situation, and aims to provide an adhesive film that is unlikely to trap air bubbles between the adhesive layer and the substrate when attached to the substrate, and in which traces of the uneven structure on the surface of the adhesive layer are difficult to see when observed from the substrate side, and a method for manufacturing the adhesive film. [Means for solving the problem]

[0006] (1) One embodiment of the present invention is an adhesive film having a resin film and an adhesive layer, wherein the surface of the adhesive layer opposite to the resin film has an arithmetic mean roughness of 3.5 μm or more and 14.0 μm or less and a maximum height of 20.0 μm or more and 75.0 μm or less.

[0007] (2) Furthermore, one embodiment of the present invention is a pressure-sensitive adhesive film that, in addition to the configuration of (1) above, further comprises a primer layer between the resin film and the pressure-sensitive adhesive layer.

[0008] (3) Furthermore, in one embodiment of the present invention, in addition to the configuration of (2) above, the primer layer is a pressure-sensitive adhesive film containing a monoaminoethylated acrylic polymer.

[0009] (4) Furthermore, in one embodiment of the present invention, in addition to the configuration of any one of (1) to (3) above, the pressure-sensitive adhesive layer comprises a polyester-based pressure-sensitive adhesive.

[0010] (5) Furthermore, in addition to the configuration of (2), one embodiment of the present invention is a pressure-sensitive adhesive film, wherein the primer layer contains a monoaminoethylated acrylic polymer and the pressure-sensitive adhesive layer contains a polyester-based pressure-sensitive adhesive.

[0011] (6) Furthermore, in one embodiment of the present invention, in addition to the configuration of any one of (1) to (5) above, the pressure-sensitive adhesive film is one in which the pressure-sensitive adhesive layer contains a hot-melt pressure-sensitive adhesive.

[0012] (7) Furthermore, in one embodiment of the present invention, in addition to any one of the configurations (1) to (6) above, the resin film is an adhesive film containing polyvinyl chloride, an acrylic resin, an acrylonitrile-butadiene-styrene copolymer, or polycarbonate.

[0013] (8) Furthermore, in one embodiment of the present invention, in addition to the configuration of any one of (1) to (6) above, the resin film is an adhesive film containing polyvinyl chloride.

[0014] (9) Furthermore, one embodiment of the present invention is an adhesive film having any one of the configurations (2) to (8) above, wherein the resin film contains polyvinyl chloride and the primer layer contains a monoaminoethylated acrylic polymer.

[0015] (10) Furthermore, in addition to the configuration of any one of (1) to (9), one embodiment of the present invention is an adhesive film, wherein the resin film contains polyvinyl chloride and the adhesive layer contains a polyester-based adhesive.

[0016] (11) Furthermore, one embodiment of the present invention is an adhesive film having the configuration of any one of (1) to (10) above, and further having a design layer on the surface of the resin film opposite the adhesive layer side.

[0017] (12) Furthermore, one embodiment of the present invention is an adhesive film that, in addition to the configuration of (11) above, further has another resin film on the surface of the design layer opposite the resin film side.

[0018] (13) Furthermore, in one embodiment of the present invention, in addition to any one of the configurations (1) to (12) above, the resin film is an adhesive film having a breaking strength of 1.5 MPa or more and 30 MPa or less at a temperature of 100°C, and a breaking elongation of 100% or more at a temperature of 100°C.

[0019] (14) Another embodiment of the present invention is a method for producing a pressure-sensitive adhesive film, comprising: a pressure-sensitive adhesive layer forming step of forming a pressure-sensitive adhesive layer on a surface of a separator; a pressure-sensitive adhesive layer laminating step of laminating the resin film and the pressure-sensitive adhesive layer so that the surface of the pressure-sensitive adhesive layer opposite the separator side is the resin film side; and a concavo-convex structure forming step of pressing a mold having an arithmetic mean roughness of 3.5 μm or more and 14.0 μm or less and a maximum height of 20.0 μm or more and 75.0 μm or less against a laminate having the separator, the mold being from the side of the separator opposite to the side contacting the pressure-sensitive adhesive layer, to form a concavo-convex structure on the surface of the pressure-sensitive adhesive layer.

[0020] (15) Furthermore, in addition to the configuration of (14), one embodiment of the present invention is a method for producing a pressure-sensitive adhesive film, which includes a step of forming a primer layer on one side of the resin film before the pressure-sensitive adhesive layer lamination step, and in the pressure-sensitive adhesive layer lamination step, the resin film and the pressure-sensitive adhesive layer are laminated via the primer layer.

[0021] (16) Furthermore, in addition to the configuration of (14), one embodiment of the present invention further comprises, before the adhesive layer lamination step, a step of forming a primer layer on one side of the resin film and a step of forming a design layer on the other side of the resin film, and in the adhesive layer lamination step, the resin film and the adhesive layer are laminated via the primer layer.

[0022] (17) Furthermore, in addition to the configuration of (14) above, one embodiment of the present invention further includes, before the adhesive layer lamination step, a step of forming a design layer on one side of another resin film, a film lamination step of laminating the resin film and the other resin film so that one side of the resin film and the design layer are in contact, and a step of forming a primer layer on the side of the resin film opposite to the side in contact with the design layer, wherein in the adhesive layer lamination step, the resin film and the adhesive layer are laminated via the primer layer. [Effects of the Invention]

[0023] According to the present invention, it is possible to provide an adhesive film in which, even when attached to a substrate, air bubbles are unlikely to be trapped between the adhesive layer and the substrate, and when observed from the substrate side, traces of the uneven structure on the surface of the adhesive layer are difficult to see, and a method for manufacturing the adhesive film. [Brief explanation of the drawings]

[0024] [Figure 1] 1 is a cross-sectional view showing an example of a pressure-sensitive adhesive film according to embodiment 1. FIG. [Figure 2] 3 is a cross-sectional view showing another example of the pressure-sensitive adhesive film according to embodiment 1. FIG. [Figure 3] FIG. 4 is a cross-sectional view showing an example of a decorated molded product according to a second embodiment. [Figure 4A] 10 is a cross-sectional view illustrating an example of a step of forming a design layer in the method for producing a resin film according to embodiment 3. FIG. [Figure 4B] 10 is a cross-sectional view illustrating an example of a film laminating step in the method for producing a resin film according to Embodiment 3. FIG. [Figure 4C] FIG. 10 is a cross-sectional view illustrating an example of a step of forming a primer layer in the method for producing a resin film according to Embodiment 3. [Figure 4D] 10 is a cross-sectional view illustrating an example of a pressure-sensitive adhesive layer forming step in the method for producing a resin film according to Embodiment 3. FIG. [Figure 4E]10 is a cross-sectional view illustrating an example of a pressure-sensitive adhesive layer laminating step in the method for producing a resin film according to Embodiment 3. FIG. [Figure 4F] FIG. 10 is a cross-sectional view illustrating an example of a step of forming a concave-convex structure on the surface of a pressure-sensitive adhesive layer in a method for producing a resin film according to embodiment 3. [Figure 5A] 10 is a cross-sectional view illustrating an example of a pressure-sensitive adhesive layer forming step in the method for producing a resin film according to Embodiment 4. FIG. [Figure 5B] 10 is a cross-sectional view illustrating an example of a pressure-sensitive adhesive layer laminating step in the method for producing a resin film according to Embodiment 4. FIG. [Figure 6] FIG. 2 is a schematic diagram of an embossing roll illustrating the position of a measurement area for the surface roughness of the embossing roll. [Figure 7] FIG. 2 is a schematic diagram illustrating a method for measuring the surface roughness of a pressure-sensitive adhesive layer of a pressure-sensitive adhesive film. DETAILED DESCRIPTION OF THE INVENTION

[0025] The following describes embodiments of the present invention. The present invention is not limited to the contents described in the following embodiments, and appropriate design changes can be made within the scope of the configuration of the present invention.

[0026] <Embodiment 1> Fig. 1 is a cross-sectional schematic diagram showing an example of a pressure-sensitive adhesive film according to embodiment 1. As shown in Fig. 1, a pressure-sensitive adhesive film 10 according to the embodiment has a resin film 1 and a pressure-sensitive adhesive layer 2. The pressure-sensitive adhesive film 10 may further have a primer layer 3 between the resin film 1 and the pressure-sensitive adhesive layer 2.

[0027] (resin film) The resin film 1 is a film that serves as a support for the adhesive film 10, and preferably contains a thermoplastic resin. The resin film 1 more preferably contains polyvinyl chloride, acrylic resin, acrylonitrile-butadiene-styrene copolymer (ABS resin), or polycarbonate. Polyvinyl chloride, acrylic resin, ABS resin, and polycarbonate have good elongation at high temperatures, making them suitable as supports for adhesive films used in vacuum and pressure-sensitive molding. Of these, the resin film 1 more preferably contains polyvinyl chloride because of its good elongation at high temperatures.

[0028] A polyvinyl chloride film containing polyvinyl chloride as the main resin component has good elongation, allowing it to conform to the surface shape of the substrate and be less likely to break when attached to a substrate. Furthermore, when attached to a substrate for integrated lamination molding, molding can be performed at a relatively low temperature (approximately 120°C). "Containing polyvinyl chloride as the main resin component" means that the polyvinyl chloride content of the total resin components contained in the resin film 1 is 50% by mass or more, preferably 70% by mass or more, more preferably 90% by mass or more, and even more preferably 100%. Note that "relatively low temperature" refers to a temperature lower than the molding temperature (over 130°C) when molding resins other than polyvinyl chloride and acrylic resins (e.g., polyethylene terephthalate).

[0029] Examples of the polyvinyl chloride include a homopolymer of vinyl chloride and a copolymer of vinyl chloride with other monomers.

[0030] Examples of the other monomers include vinyl esters such as vinyl acetate and vinyl propionate; olefins such as ethylene, propylene, and styrene; (meth)acrylic acid esters such as methyl acrylate, ethyl acrylate, and methyl methacrylate; 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.

[0031] The content of the other monomer in the copolymer is usually 50% by mass or less, preferably 10% by mass or less. When it is 50% by mass or less, the flex resistance of the film can be improved. Among the polyvinyl chlorides, a homopolymer of vinyl chloride is preferred because it can provide dimensional stability.

[0032] The average degree of polymerization of the polyvinyl chloride may be, for example, 750 or more and 1300 or less. A preferred lower limit of the average degree of polymerization is 800. When the average degree of polymerization is within the range of 750 or more and 1300 or less, moldability at relatively low temperatures is good. In particular, when the average degree of polymerization is 750 or more, the film can stretch more sufficiently when the pressure-sensitive adhesive film of the present invention is integrally laminated with a substrate, and can better follow the shape of the substrate. Furthermore, when the average degree of polymerization is 1300 or less, processability in calendar molding to obtain a polyvinyl chloride film is improved, the appearance of the film surface is improved, and an increase in the shrinkage rate of the film after molding is further suppressed, making it easier to maintain its shape. The average degree of polymerization of the polyvinyl chloride means the average degree of polymerization measured in accordance with JIS K6721 "Test Methods for Polyvinyl Chloride."

[0033] The polyvinyl chloride film preferably contains a plasticizer. The content of the plasticizer is preferably 7 parts by mass or more and 35 parts by mass or less per 100 parts by mass of polyvinyl chloride. By setting the content of the plasticizer within the above range, flexibility and formability suitable for calendering and the like can be obtained. Furthermore, elongation suitable for attaching the pressure-sensitive adhesive film of the present invention to a substrate and performing vacuum / pressure molding and the like can be obtained. When the content of the plasticizer is 7 parts by mass or more, the polyvinyl chloride film does not become too hard, and breakage of the film during molding can be suppressed. On the other hand, when the content is 35 parts by mass or less, the polyvinyl chloride film does not become too soft, and handleability can be improved. A more preferred lower limit of the content of the plasticizer per 100 parts by mass of polyvinyl chloride is 15 parts by mass, a more preferred upper limit is 30 parts by mass, and an even more preferred upper limit is 25 parts by mass.

[0034] Examples of the plasticizer include phthalate diesters such as bis(2-ethylhexyl) phthalate (DOP), diisononyl phthalate (DINP), diisodecyl phthalate (DIDP), and diundecyl phthalate (DUP); aliphatic dibasic acid diesters such as dioctyl adipate and dioctyl sebacate; phosphate triesters such as tricresyl phosphate and trioctyl phosphate; epoxy-based plasticizers such as epoxidized soybean oil and epoxy resins; and polymer polyester plasticizers. Among these, phthalate diesters are preferred. DUP is the most suitable plasticizer because it is not subject to various environmental regulations, produces little odor during film formation, and causes little contamination of the molding machine during film formation.

[0035] The thickness of the resin film 1 is preferably 50 μm or more and 150 μm or less. A thickness of 50 μm or more can facilitate calendaring. Specifically, if foreign matter or resin degradation products generated during processing are mixed in, the resin film may tear or develop holes during calendaring. However, if the thickness of the resin film 1 is within the above range, these phenomena are more effectively prevented. On the other hand, if the thickness is 150 μm or less, a sufficient amount of heat can be obtained when thermally laminating with other films, etc., and a decrease in processing speed is more effectively prevented. Furthermore, if the thickness is 150 μm or less, the overall thickness of the adhesive film is reduced, thereby improving processability when laminating and integrating the adhesive film 10 with a substrate. The thickness is more preferably 80 μm or more and 100 μm or less.

[0036] The resin film 1 may be light-transmitting or light-blocking, but as will be described later, when a design layer is disposed on the back surface of the resin film 1, the resin film 1 is preferably transparent, and for example, preferably has a total light transmittance of 70% or more, more preferably 80% or more. On the other hand, when it is desired to obscure the background of the resin film 1, the resin film 1 is preferably light-blocking, and for example, preferably has a total light transmittance of 3% or less, more preferably 2.8% or less. In this specification, the total light transmittance is a value based on JIS K 7375:2008.

[0037] When the resin film 1 is used to impart color to the adhesive film 10, the resin film 1 may be a colored film containing a coloring agent.

[0038] The resin film 1 preferably has a breaking strength of 1.5 MPa or more and 30 MPa or less at 100°C, and a breaking elongation of 100% or more at 100°C. When the breaking strength and breaking elongation are within the above ranges, the resin film can be sufficiently elongated even under the pressure of vacuum pressure forming when attached to a substrate, and can sufficiently conform to the surface shape of the substrate. The breaking strength of the resin film 1 is more preferably 2.0 MPa or more and 20 MPa or less, and particularly preferably 2.0 MPa or more and 10 MPa or less. The breaking elongation of the resin film 1 is more preferably 200% or more, and even more preferably 300% or more.

[0039] The breaking strength and breaking elongation can be measured under the following conditions by a method in accordance with American Society for Testing and Materials (ASTM) D882. Measurement equipment, analysis software, etc.: Shimadzu Corporation's precision universal testing machine Autograph AG-Xplus, video-type non-contact extensometer TRViewx and TRAPENZIUM (software) Pulling speed: 200mm / min Test piece shape: Dumbbell type No. 1 ·Distance between gauge lines: 80mm

[0040] (Adhesive layer) The surface of the adhesive layer 2 opposite the resin film 1 side has an uneven structure. The surface of the adhesive layer 2 opposite the resin film 1 side has an arithmetic mean roughness Ra of 3.5 μm or more and 14.0 μm or less, and a maximum height Rz of 20.0 μm or more and 75.0 μm or less. By setting the arithmetic mean roughness and maximum height of the surface of the adhesive layer 2 opposite the resin film 1 side within the above ranges, when the adhesive film 10 is attached to a substrate via the adhesive layer 2, air bubbles are less likely to be trapped between the adhesive layer 2 and the substrate (air entrapment is less likely). If the substrate is a transparent substrate, traces of the uneven structure on the surface of the adhesive layer 2 can be made less visible when the decorated molded product is observed from the substrate side. If the Ra is less than 3.5 μm, air is less likely to escape between the adhesive layer 2 and the substrate, and the occurrence of air entrapment cannot be suppressed. On the other hand, if the Ra exceeds 14.0 μm, direct contact between the grooves of the recesses on the surface of the pressure-sensitive adhesive layer 2 and the substrate cannot occur during molding, and there is a possibility that shapes derived from the uneven structure on the surface of the pressure-sensitive adhesive layer 2 will remain. If the Rz exceeds 75.0 μm, traces of the uneven structure on the surface of the pressure-sensitive adhesive layer 2 will become more easily visible. The lower the Rz, the less visible the traces of the uneven structure on the surface of the pressure-sensitive adhesive layer 2 will be, but in consideration of achieving both the suppression of air entrapment and the like, the Rz is preferably 20.0 μm or more.

[0041] The air entrapment is an air layer that occurs between the adhesive film 10 and the substrate when the adhesive film 10 is attached to the substrate. The occurrence of air entrapment significantly impairs the design, particularly when the adhesive film is attached to the backside of a transparent substrate and the adhesive film is observed through the substrate.

[0042] In this specification, the arithmetic mean roughness Ra and the maximum height Rz are values ​​measured by a method conforming to JIS B 0601: 2001. As a measuring device, for example, a surface roughness measuring instrument (SURTEST SJ-310) manufactured by Mitutoyo Corporation can be used.

[0043] The MD (Machine Direction) direction of the PSA film is also called the machine direction, and refers to the direction in which the PSA film is transported. The TD (Transverse Direction) direction of the film is also called the width direction, and refers to the direction perpendicular to the MD direction. In this specification, the oblique direction refers to a direction that forms an angle of 45° with respect to the MD and TD directions. The arithmetic mean roughness Ra of the surface of the PSA layer 2 opposite to the resin film 1 side in any one of the MD, TD, and oblique directions may be 3.5 μm or more and 14.0 μm or less. Furthermore, the maximum height Rz of the surface of the PSA layer 2 opposite to the resin film 1 side in any one of the MD, TD, and oblique directions may be 20.0 μm or more and 75.0 μm or less.

[0044] The Ra in the MD direction, the Ra in the TD direction, and the Ra in the oblique direction are obtained by setting a predetermined reference length along the MD direction, the TD direction, and the oblique direction of the PSA film, respectively, and calculating the average value of Ra in the MD direction, the average value of Ra in the TD direction, and the average value of Ra in the oblique direction measured in an arbitrary number of measurement areas. The Rz in the MD direction, the Rz in the TD direction, and the Rz in the oblique direction are obtained by setting a predetermined reference length along the MD direction, the TD direction, and the oblique direction of the PSA film, respectively, the same as the Ra, and calculating the average value of Rz in the MD direction, the average value of Rz in the TD direction, and the average value of Rz in the oblique direction measured in the same number of measurement areas as the Ra. The arbitrary number of measurement areas is preferably 5 or more, and more preferably 10 or more. The reference length is, for example, 2.5 mm.

[0045] In this specification, the average value of the total "number of measurement areas × 3" values ​​of Ra in the MD direction, Ra in the TD direction, and Ra in the oblique directions measured in the above-mentioned arbitrary number of measurement areas is also referred to as the overall arithmetic mean roughness, and it is more preferable that the overall arithmetic mean roughness is 3.5 μm or more and 14.0 μm or less. Furthermore, the average value of the total "number of measurement areas × 3" values ​​of Rz in the MD direction, Rz in the TD direction, and Rz in the oblique directions measured in the above-mentioned arbitrary number of measurement areas is also referred to as the overall maximum height, and it is more preferable that the overall maximum height is 20.0 μm or more and 75.0 μm or less.

[0046] The arithmetic mean roughness Ra of the surface of the pressure-sensitive adhesive layer 2 opposite the resin film 1 side is more preferably 3.5 μm or more and 13.5 μm or less, and even more preferably 6.0 μm or more and 12.5 μm or less. The maximum height Rz of the surface of the pressure-sensitive adhesive layer 2 opposite the resin film 1 side is more preferably 68.0 μm or less. From the viewpoint of making the traces of the uneven structure on the surface of the pressure-sensitive adhesive layer 2 less visible and suppressing the air entrapment, it is particularly preferable that the Ra be 7.0 μm or more and 12.5 μm or less, and the Rz be 38.5 μm or more and 63.5 μm or less. It is preferable that Ra in any one of the MD direction, TD direction, and oblique directions be within the above numerical range of Ra, and it is more preferable that the overall arithmetic mean roughness be within the above numerical range of Ra. It is also preferable that Rz in any one of the MD direction, TD direction, and oblique directions be within the above numerical range of Rz, and it is more preferable that the overall maximum height be within the above numerical range of Rz.

[0047] The standard deviation of the arithmetic mean roughness Ra of the surface of the pressure-sensitive adhesive layer 2 opposite to the resin film 1 side is preferably 0.3 μm or more and 2.1 μm or less. The standard deviation of the maximum height Rz of the surface of the pressure-sensitive adhesive layer 2 opposite to the resin film 1 side is preferably 1.5 μm or more and 11.5 μm or less. The standard deviation of Ra can be determined from the total numerical value of the MD Ra, TD Ra, and oblique Ra measured in the above-mentioned arbitrary number of measurement areas (number of measurement areas x 3). The standard deviation of Rz can be determined from the total numerical value of the MD Rz, TD Rz, and oblique Rz measured in the above-mentioned arbitrary number of measurement areas (number of measurement areas x 3).

[0048] Examples of the uneven structure on the surface of the pressure-sensitive adhesive layer 2 include textured finishes such as matte and matte finishes, geometric patterns, wood grain patterns, hairline patterns, and leather grain patterns. The uneven structure can be formed, for example, by forming a pressure-sensitive adhesive layer on a separator, laminating it with a resin film, and then embossing the separator from the separator side, or by forming a pressure-sensitive adhesive layer on the surface of a separator with an uneven structure formed on its surface, and pressing a member with a pre-formed uneven structure onto the surface of the pressure-sensitive adhesive layer 2 to transfer the uneven structure to the surface of the pressure-sensitive adhesive layer 2. It is preferable that the pressure-sensitive adhesive layer 2 does not contain fine particles such as silica particles.

[0049] The pressure-sensitive adhesive layer 2 preferably contains a polyester-based pressure-sensitive adhesive. By containing a polyester-based pressure-sensitive adhesive, a pressure-sensitive adhesive layer 2 having excellent adhesive properties and heat resistance at high temperatures can be obtained. Examples of the polyester-based pressure-sensitive adhesive include "UX-4099-45EA" manufactured by Unitika Ltd. and "Vylon (registered trademark) BX-10ss" manufactured by Toyobo Co., Ltd.

[0050] The pressure-sensitive adhesive layer 2 may contain a curing agent. The curing agent is preferably an isocyanate-based curing agent. The isocyanate-based curing agent preferably includes xylylene diisocyanate (XDI) such as meta-xylylene diisocyanate; hydrogenated xylylene diisocyanate (H6XDI) such as 1,4-bis(isocyanatomethyl)cyclohexane; isophorone diisocyanate (IPDI); hexamethylene diisocyanate (HDI); or pentamethylene diisocyanate (PDI) such as 1,5-pentamethylene diisocyanate. Specific examples of the isocyanate-based curing agent include "Desmodur L-75(C)" manufactured by Sumika Covestro Urethane Co., Ltd. and "Stabio (registered trademark) D-370N" manufactured by Mitsui Chemicals, Inc.

[0051] The content of the curing agent relative to 100 parts by mass of the polyester-based pressure-sensitive adhesive is preferably 0.5 parts by mass or more and 3.5 parts by mass or less. When the content of the curing agent is 0.5 parts by mass or more, heat resistance can be improved. The content of the curing agent is more preferably 0.5 parts by mass or more and 2.5 parts by mass or less.

[0052] The polyester-based pressure-sensitive adhesive preferably has an NCO index, represented by the following formula (1), of 0.4 or more and 1.6 or less. NCO index = moles of NCO groups derived from the isocyanate component contained in the isocyanate-based curing agent / moles of OH groups derived from the polyester contained in the polyester-based adhesive (base resin) (1)

[0053] The pressure-sensitive adhesive layer 2 preferably contains a hot-melt pressure-sensitive adhesive. The hot-melt pressure-sensitive adhesive layer containing the hot-melt pressure-sensitive adhesive preferably exhibits adhesive strength at the molding temperature of the pressure-sensitive adhesive film 10, and preferably has a softening point of, for example, 80° C. or higher and 150° C. or lower. The softening point can be measured by a method in accordance with JIS K6863:1994.

[0054] The pressure-sensitive adhesive layer 2 is preferably transparent. The total light transmittance of the pressure-sensitive adhesive layer 2 is preferably 70% or more, and more preferably 80% or more.

[0055] (Primer layer) 1, by providing the primer layer 3 between the resin film 1 and the pressure-sensitive adhesive layer 2, it is possible to increase the adhesion between the resin film 1 and the pressure-sensitive adhesive layer 2, and it is possible to prevent peeling between the resin film 1 and the pressure-sensitive adhesive layer 2 even when the pressure-sensitive adhesive film 10 is attached to a substrate while being stretched, as in vacuum pressure forming. The primer layer 3 is preferably in contact with the resin film 1 and the pressure-sensitive adhesive layer 2.

[0056] The primer layer 3 preferably contains a monoaminoethylated acrylic polymer. When the primer layer contains a monoaminoethylated acrylic polymer, the adhesion between the resin film 1 and the pressure-sensitive adhesive layer 2 is improved. Furthermore, when the pressure-sensitive adhesive film 10 is attached to a substrate, long-term adhesion can be ensured. Examples of the monoaminoethylated acrylic polymer include Polyment (registered trademark) NK-380 manufactured by Nippon Shokubai Co., Ltd.

[0057] In the pressure-sensitive adhesive film 10, the primer layer 3 preferably contains a monoaminoethylated acrylic polymer, and the pressure-sensitive adhesive layer 2 preferably contains a polyester-based pressure-sensitive adhesive. In the pressure-sensitive adhesive film 10, the resin film 1 preferably contains polyvinyl chloride, and the primer layer 3 preferably contains a monoaminoethylated acrylic polymer. In the pressure-sensitive adhesive film 10, the resin film 1 preferably contains polyvinyl chloride, and the pressure-sensitive adhesive layer 2 preferably contains a polyester-based pressure-sensitive adhesive. Furthermore, in the pressure-sensitive adhesive film 10, the resin film 1 preferably contains polyvinyl chloride, the pressure-sensitive adhesive layer 2 preferably contains a polyester-based pressure-sensitive adhesive, and the primer layer 3 preferably contains a monoaminoethylated acrylic polymer.

[0058] The primer layer 3 can be obtained by applying a primer layer-forming composition containing a monoaminoethylated acrylic polymer and then drying it. The content (solid content) of the monoaminoethylated acrylic polymer in the primer layer-forming composition is preferably 29% by mass or more and 31% by mass or less based on 100% by mass of the total solid content of the primer layer-forming composition.

[0059] (Design layer) Figure 2 is a cross-sectional schematic diagram showing another example of the adhesive film according to embodiment 1. As shown in Figure 2, the adhesive film 10 may further have a design layer 4 on the surface of the resin film 1 opposite the adhesive layer 2. By disposing the design layer 4 on the surface of the resin film 1 opposite the adhesive layer 2, it is possible to prevent the ink in the design layer 4 from bleeding due to components contained in the adhesive layer 2 and the primer layer 3.

[0060] The design layer 4 is a layer that imparts a design, such as color or pattern, to the adhesive film, and is obtained, for example, by printing with ink. The ink may contain coloring materials, binder resins, solvents, etc. Examples of the coloring materials include pigments, dyes, and inorganic fillers such as titanium oxide. Examples of the binder resins include vinyl acetate and acrylic resins. The thickness of the design layer 4 is, for example, 1 μm or more and 10 μm or less.

[0061] When a design layer is placed on the back surface of the resin film 1, it is preferable that the resin film 1, adhesive layer 2 and primer layer 3 are transparent so that the design layer 4 can be seen through the substrate, and for example, it is preferable that the total light transmittance is 70% or more, and more preferably 80% or more.

[0062] (Other resin films) As shown in Figure 2, the adhesive film 10 may further have another resin film 5 on the surface of the design layer 4 opposite the resin film 1 side. Alternatively, the design layer 4 may not be disposed and another resin film 5 may be disposed on the surface of the resin film 1 opposite the adhesive layer 2 side. Hereinafter, the resin film 1 will be referred to as the first resin film 1, and the other resin film 5 will be referred to as the second resin film 5. It is preferable that the design layer 4 be in contact with at least one of the first resin film 1 and the second resin film 5, and it is more preferable that the design layer 4 be in contact with both the first resin film 1 and the second resin film 5.

[0063] The second resin film 5 preferably contains a thermoplastic resin. The second resin film 5 more preferably contains polyvinyl chloride, acrylic resin, ABS resin, or polycarbonate. Among these, the second resin film 5 more preferably contains polyvinyl chloride.

[0064] The second resin film 5 preferably has formability equivalent to that of the first resin film 1. When the first resin film 1 is a polyvinyl chloride film, the second resin film 5 is also preferably a polyvinyl chloride film. As the second resin film 5, a polyvinyl chloride film similar to that described for the first resin film 1 in terms of the average degree of polymerization of polyvinyl chloride and the type and content of plasticizer can be used. From the viewpoint of improving the design of the pressure-sensitive adhesive film, the second resin film 5 may be a colored film.

[0065] The thickness of the second resin film 5 is preferably 50 μm or more and 150 μm or less, and more preferably 80 μm or more and 100 μm or less.

[0066] The second resin film 5 may be light-transmitting or light-blocking. When the second resin film 5 is disposed on the rearmost surface of the PSA film 10, the second resin film 5 may be light-blocking.

[0067] The adhesive film 10 may further have other layers, such as a metal vapor deposition film or a light-shielding layer on the back side of the second resin film 5.

[0068] The total thickness of the adhesive film 10 is preferably 100 μm or more and 450 μm or less, and more preferably 240 μm or more and 350 μm or less.

[0069] <Embodiment 2> FIG. 3 is a cross-sectional schematic diagram showing an example of a decorated molded product according to embodiment 2. A decorated molded product having an adhesive film according to the embodiment and a substrate is also one embodiment of the present invention. The adhesive film 10 can be suitably used to impart design to the substrate. A structure in which the adhesive film 10 is attached to a substrate is also called a decorated molded product. FIG. 3 illustrates an example in which the adhesive film 10 shown in FIG. 2 is attached to a substrate 20, but the adhesive film shown in FIG. 1 may also be used as the adhesive film 10.

[0070] As shown in Fig. 3, the adhesive film 10 is attached to the substrate 20 via the adhesive layer 2. It is preferable that the substrate 20 of the decorated molded product 100 faces the viewer. That is, it is preferable that the adhesive film 10 is attached to the back surface of the substrate 20. As shown in Figs. 1 and 2, the adhesive layer 2 of the adhesive film 10 has a predetermined arithmetic mean roughness and maximum height, so that air is less likely to become trapped between the adhesive layer 2 and the substrate 20. Therefore, even when the decorated molded product 100 is observed from the front side of the substrate 20 through the substrate 20, no air bubbles are visible, and the decorative molded product 100 has excellent design properties.

[0071] (base material) The substrate 20 is an adherend for the pressure-sensitive adhesive film according to the embodiment. Examples of the substrate include resin substrates such as acrylic resins such as polymethyl methacrylate, polycarbonate, ABS resin, polyethylene terephthalate, and polystyrene, and glass substrates. Among these, resin substrates such as acrylic resins, polycarbonate, and ABS resin, and glass substrates are preferred because of their excellent transparency. Glass substrates also have excellent weather resistance, making them suitable for use in outdoor applications of decorated molded products. The substrate may have a curved surface.

[0072] The substrate needs only to have a transparency sufficient to allow the adhesive film 10 to be seen through the substrate from the front side, and preferably has a total light transmittance of 80% or more, and more preferably has a total light transmittance of 90% or more.

[0073] Examples of the substrate include housing construction materials, furniture, home appliances or components thereof, windows, interior materials for vehicles, and outdoor charging stations.

[0074] Methods for attaching the adhesive film 10 to the substrate 20 include, for example, a method of heating the adhesive film 10 and attaching it to the substrate 20. Examples include thermoforming, vacuum forming, pressure forming, vacuum-pressure forming, in-mold forming, etc. Among these, vacuum forming, pressure forming, and vacuum-pressure forming (hereinafter also referred to as vacuum-pressure forming, etc.) are preferred because they facilitate attachment to substrates with complex three-dimensional shapes. Furthermore, vacuum forming, pressure forming, and vacuum-pressure forming, which do not require a jig, are suitable for substrates that are fragile, such as glass.

[0075] Vacuum forming is a molding method in which a vacuum is created inside the molding chamber of a molding machine in which a substrate and an adhesive film are placed, thereby bonding the adhesive film to the substrate. Pressure forming is a molding method in which compressed air is used to pressurize the molding chamber, thereby bonding the adhesive film to the substrate. Vacuum-pressure forming is a molding method in which a vacuum is created inside the molding chamber, and then pressure is applied under vacuum conditions to bond the adhesive film to the substrate. The adhesive film 10 can be suitably used as a decorative film for vacuum forming, pressure forming, or vacuum-pressure forming.

[0076] As the vacuum / pressure forming device, a TOM forming machine (NGF-0406-T manufactured by Fuse Vacuum Co., Ltd.) or the like can be used. The forming temperature (heating temperature of the film) in the vacuum / pressure forming is, for example, 110°C or higher and 140°C or lower. In particular, when the substrate is glass, the heating temperature is preferably 120°C or higher and 130°C or lower.

[0077] <Embodiment 3> Another embodiment of the present invention is a method for producing a pressure-sensitive adhesive film, comprising: an adhesive layer forming step of forming an adhesive layer on the surface of a separator; an adhesive layer laminating step of laminating the resin film and the adhesive layer so that the surface of the adhesive layer opposite the separator side is the resin film side; and an uneven structure forming step of pressing a mold having an arithmetic mean roughness of 3.5 μm or more and 14.0 μm or less and a maximum height of 20.0 μm or more and 75.0 μm or less against a laminate having the separator, the mold being from the side of the separator opposite to the side contacting the adhesive layer, to form an uneven structure on the surface of the adhesive layer.

[0078] The pressure-sensitive adhesive layer forming step is a step of forming a pressure-sensitive adhesive layer on the surface of the separator. The pressure-sensitive adhesive layer can be the same as the pressure-sensitive adhesive layer 2 in embodiment 1, and therefore a description thereof will be omitted. The method for forming the pressure-sensitive adhesive layer is not particularly limited, and a conventionally known method, such as a method of applying a pressure-sensitive adhesive composition onto a separator using a bar coater or the like and drying the applied composition, can be used.

[0079] The separator serves as a support for the pressure-sensitive adhesive layer and protects the surface of the pressure-sensitive adhesive layer. When the pressure-sensitive adhesive film is attached to a substrate, the separator is removed, and the exposed pressure-sensitive adhesive layer is attached by contacting it with the back surface of the substrate.

[0080] Examples of separators include polyethylene terephthalate (PET). The thickness of the separator is preferably 34 μm or more and 42 μm or less. A separator having a thickness within the above range is suitable for a manufacturing method in which a mold or the like is pressed against the pressure-sensitive adhesive layer 2 through the separator to impart a concave-convex structure to the pressure-sensitive adhesive layer. The thickness of the separator is more preferably 37 μm or more and 39 μm or less.

[0081] In the third embodiment, the surface of the separator on which the pressure-sensitive adhesive layer is formed may be flat, and for example, the arithmetic mean roughness Ra may be 1.0 μm or less, and more preferably 0.5 μm or less.

[0082] The pressure-sensitive adhesive layer laminating step is a step of laminating the resin film and the pressure-sensitive adhesive layer so that the surface of the pressure-sensitive adhesive layer opposite to the separator side faces the resin film.

[0083] The thickness of the pressure-sensitive adhesive layer is preferably 20 μm or more and 60 μm or less. When the thickness is 20 μm or more, sufficient adhesive strength to the substrate can be obtained. The thickness is more preferably 35 μm or more and 50 μm or less.

[0084] The resin film can be produced by calendering. Calendering is a method of forming a film by rolling a raw resin (resin composition) while sandwiching it between a pair of resin or metal cylinders (calender rolls). As the resin film, the same one as the resin film 1 of embodiment 1 can be used, and therefore a description thereof will be omitted.

[0085] An adhesive film can be produced by laminating the surface of the adhesive layer opposite to the separator to a resin film.

[0086] The uneven structure forming step is a step of pressing a mold against a laminate having the separator, the pressure-sensitive adhesive layer, and the resin film in this order from the side opposite to the side of the separator that contacts the pressure-sensitive adhesive layer to form an uneven structure on the surface of the pressure-sensitive adhesive layer. By pressing the mold against the side of the separator that contacts the pressure-sensitive adhesive layer, the uneven structure on the surface of the mold is transferred to the separator, and an uneven structure corresponding to the uneven structure of the separator is transferred to the surface of the pressure-sensitive adhesive layer. If the mold is brought into direct contact with the surface of the pressure-sensitive adhesive layer, the pressure-sensitive adhesive layer will stick to the mold, making it difficult to impart the desired uneven structure to the surface of the pressure-sensitive adhesive layer. By pressing the mold over the separator, it is possible to prevent the pressure-sensitive adhesive layer from sticking to the mold while suppressing the inclusion of dust, dirt, etc.

[0087] The mold has an arithmetic mean roughness of 3.5 μm or more and 14.0 μm or less, and a maximum height of 20.0 μm or more and 75.0 μm or less. By setting the arithmetic mean roughness and maximum height of the mold surface that contacts the separator within the above ranges, a predetermined uneven structure can be formed on the surface of the pressure-sensitive adhesive layer that contacts the separator, and when a pressure-sensitive adhesive film is attached to a substrate via the pressure-sensitive adhesive layer, air bubbles are unlikely to be trapped between the pressure-sensitive adhesive layer and the substrate, and a pressure-sensitive adhesive film can be produced in which traces of the uneven structure on the surface of the pressure-sensitive adhesive layer are difficult to see when the decorated molded product is observed from the substrate side.

[0088] If the directions corresponding to the MD, TD, and oblique directions of the resulting film are the MD, TD, and oblique directions of the surface of the mold that contacts the separator (hereinafter also referred to as the surface of the mold), then the arithmetic mean roughness Ra of the mold surface in any one of the MD, TD, and oblique directions should be 3.5 μm or more and 14.0 μm or less, and the maximum height Rz of the mold surface in any one of the MD, TD, and oblique directions should be 20.0 μm or more and 75.0 μm or less.

[0089] The Ra in the MD direction, Ra in the TD direction, and Ra in the oblique directions of the mold surface are obtained by setting predetermined reference lengths along the MD direction, TD direction, and oblique directions of the mold surface, respectively, and calculating the average value of Ra in the MD direction, the average value of Ra in the TD direction, and the average value of Ra in the oblique directions measured in any number of measurement areas. The method for calculating Ra and Rz of the mold surface can be applied by replacing "the surface of the pressure-sensitive adhesive layer opposite to the resin film side" in the method for calculating Ra and Rz of the PSA film described in embodiment 1 with "the surface of the mold in contact with the separator."

[0090] The arithmetic mean roughness Ra of the mold surface is more preferably 4.0 μm or more and 13.5 μm or less, and even more preferably 6.0 μm or more. The maximum height Rz of the mold surface is more preferably 60.0 μm or less. From the viewpoint of making the traces of the uneven structure on the surface of the pressure-sensitive adhesive layer 2 less visible and suppressing the air entrapment, it is particularly preferable that the Ra be 7.0 μm or more and 13.5 μm or less, and the Rz be 33.0 μm or more and 60.0 μm or less. It is preferable that the Ra in any one of the MD direction, TD direction, and oblique directions of the mold surface is within the above numerical range of Ra, and it is more preferable that the overall arithmetic mean roughness of the mold surface is within the above numerical range of Ra. It is also preferable that the Rz in any one of the MD direction, TD direction, and oblique directions of the mold surface is within the above numerical range of Rz, and it is more preferable that the overall maximum height of the mold surface is within the above numerical range of Rz.

[0091] The overall arithmetic mean roughness of the surface of the mold is more preferably 3.5 μm or more and 14.0 μm or less. Furthermore, the overall maximum height of the surface of the mold is more preferably 20.0 μm or more and 60.0 μm or less. The method for calculating the overall arithmetic mean roughness and overall maximum height of the surface of the mold can be applied by replacing "the surface of the pressure-sensitive adhesive layer opposite the resin film side" in the method for calculating the overall arithmetic mean roughness and overall maximum height of the PSA film described in embodiment 1 with "the surface of the mold in contact with the separator."

[0092] The standard deviation of the arithmetic mean roughness Ra of the surface of the mold is preferably 0.3 μm or more and 2.1 μm or less. The standard deviation of the maximum height Rz of the surface of the mold is preferably 1.5 μm or more and 11.5 μm or less. The method for calculating the standard deviation of the arithmetic mean roughness Ra and the standard deviation of the maximum height Rz of the surface of the mold can be applied by replacing "the surface of the pressure-sensitive adhesive layer opposite the resin film side" in the method for calculating the standard deviation of the arithmetic mean roughness Ra and the standard deviation of the maximum height Rz of the PSA film described in embodiment 1 with "the surface of the mold in contact with the separator."

[0093] The mold may be an embossing roll having a textured structure formed on the surface of a calendar roll, etc. Examples of the textured structure include a matte finish such as a grained finish or a matte finish, a geometric pattern, a wood grain pattern, a hairline pattern, a leather grain pattern, etc.

[0094] In the uneven structure forming step, a laminate having the separator, the pressure-sensitive adhesive layer, and the resin film in this order may be passed between an embossing roll and a calendering roll so that the side of the separator opposite to the side in contact with the pressure-sensitive adhesive layer is in contact with the embossing roll. In the uneven structure forming step, neither the embossing roll nor the calendering roll may be heated.

[0095] The method for producing a pressure-sensitive adhesive film according to embodiment 3 may include a step of forming a primer layer on one surface of the resin film before the pressure-sensitive adhesive layer lamination step. In this case, the resin film and the pressure-sensitive adhesive layer are laminated via the primer layer in the pressure-sensitive adhesive layer lamination step. Furthermore, it is preferable that the resin film and the primer layer are in contact with each other. The primer layer may be the same as the primer layer 3 of embodiment 1, and therefore a description thereof will be omitted. The method for forming the primer layer is not particularly limited, and a conventionally known method, such as applying a primer composition to one surface of a resin film using a gravure coater or the like and drying the applied composition, may be used.

[0096] The design layer may be formed on the resin film (first resin film) or on the other resin film (second resin film).

[0097] When the design layer is formed on another resin film (second resin film), the manufacturing method of the PSA film according to embodiment 3 may further include, before the PSA layer lamination step, a step of forming a design layer on one side of the other resin film, a film lamination step of laminating the resin film and the other resin film so that one side of the resin film and the design layer are in contact, and a step of forming a primer layer on the side of the resin film opposite to the side in contact with the design layer. In this case, in the PSA layer lamination step, the resin film and the PSA layer are laminated via the primer layer. Furthermore, it is preferable that the resin film and the primer layer are in contact with each other, the resin film and the design layer are in contact with each other, and the design layer and the other resin film are in contact with each other.

[0098] The design layer can be the same as the design layer 4 in embodiment 2, and therefore a description thereof will be omitted. The printing method for the design layer is not particularly limited, and gravure printing, offset printing, flexographic printing, screen printing, etc. can be used, but gravure printing is preferred from the viewpoint of good printability on resin films such as vinyl chloride resin films.

[0099] As the other resin film, the same one as the second resin film 5 in embodiment 2 can be used, and therefore a description thereof will be omitted. The other resin film can also be produced by calendar molding, similar to the resin film.

[0100] The film lamination step may be a thermal lamination step in which the resin film and the other resin film are bonded together while being heated, such as by passing the resin film and the other resin film in a superposed state between heated drum rolls heated to 120°C or higher and 200°C or lower.

[0101] An example of a method for producing a resin film according to embodiment 3 will be described below with reference to the drawings, but the method for producing a resin film of the present invention is not limited to the following method. Fig. 4A is a cross-sectional view illustrating an example of a step for forming a design layer in the method for producing a resin film according to embodiment 3. Fig. 4B is a cross-sectional view illustrating an example of a film lamination step in the method for producing a resin film according to embodiment 3. Fig. 4C is a cross-sectional view illustrating an example of a step for forming a primer layer in the method for producing a resin film according to embodiment 3.

[0102] As shown in Figure 4A, first, a design layer 4 is formed on one surface of a resin film (second resin film) 5. Then, as shown in Figure 4B, a first resin film 1 and a second resin film 5 are laminated together so that one surface of the resin film (first resin film) 1 contacts the design layer 4. Then, as shown in Figure 4C, a primer layer 3 is formed on the surface of the first resin film 1 opposite to the surface that contacts the design layer 4. In this way, a laminate having the primer layer 3, first resin film 1, design layer 4, and second resin film 5 in this order is produced.

[0103] 4D is a cross-sectional view illustrating an example of a pressure-sensitive adhesive layer forming step in the method for producing a resin film according to embodiment 3. FIG. 4E is a cross-sectional view illustrating an example of a pressure-sensitive adhesive layer laminating step in the method for producing a resin film according to embodiment 3. As shown in FIG. 4D, a pressure-sensitive adhesive composition is applied to the surface of separator 30 to form pressure-sensitive adhesive layer 2. Then, as shown in FIG. 4E, first resin film 1 and pressure-sensitive adhesive layer 2 are laminated together so that the surface of pressure-sensitive adhesive layer 2 opposite to separator 30 faces first resin film 1. This results in first resin film 1 and pressure-sensitive adhesive layer 2 being laminated together with primer layer 3 interposed therebetween.

[0104] Fig. 4F is a cross-sectional schematic diagram illustrating an example of a step of forming a concave-convex structure on the surface of the pressure-sensitive adhesive layer in the method for producing a resin film according to embodiment 3. As shown in Fig. 4E, a mold is pressed against a laminate having, in this order, separator 30, pressure-sensitive adhesive layer 2, primer layer 3, first resin film 1, design layer 4, and second resin film 5, from the side of separator 30 opposite to the side that contacts pressure-sensitive adhesive layer 2, to form a concave-convex structure on the surfaces of separator 30 and pressure-sensitive adhesive layer 2. Thereafter, the separator is peeled off to complete pressure-sensitive adhesive film 10 according to this embodiment.

[0105] Although the method of forming a design layer on the second resin film has been described above, the design layer may also be formed on the first resin film. When the design layer is formed on the resin film (first resin film), the method for producing a pressure-sensitive adhesive film according to embodiment 3 may further include, before the pressure-sensitive adhesive layer lamination step, a step of forming a primer layer on one side of the resin film and forming a design layer on the other side of the resin film. In this case, in the pressure-sensitive adhesive layer lamination step, the resin film and the pressure-sensitive adhesive layer are laminated via the primer layer. Furthermore, it is preferable that the resin film and the primer layer are in contact with each other, and that the resin film and the design layer are in contact with each other.

[0106] When the design layer is formed on a resin film (first resin film), the method for manufacturing an adhesive film according to embodiment 3 may include, after a step of forming a primer layer on one side of the resin film and forming a design layer on one side of the resin film, a step of laminating the resin film and the other resin film so that the design layer and the other resin film are in contact with each other.

[0107] <Embodiment 4> Yet another embodiment of the present invention is a method for producing a pressure-sensitive adhesive film, comprising: a pressure-sensitive adhesive layer forming step of forming a pressure-sensitive adhesive layer on the surface of a separator having an arithmetic mean roughness of 3.5 μm or more and 14.0 μm or less and a maximum height of 20.0 μm or more and 75.0 μm or less; and a pressure-sensitive adhesive layer laminating step of laminating the resin film and the pressure-sensitive adhesive layer so that the surface of the pressure-sensitive adhesive layer opposite the separator side faces the resin film. In embodiment 4, by forming the pressure-sensitive adhesive layer on the surface of a separator on which a concave-convex structure has been formed in advance, the concave-convex structure of the separator can be transferred to the surface of the pressure-sensitive adhesive layer.

[0108] The separator has an arithmetic mean roughness of 3.5 μm or more and 14.0 μm or less, and a maximum height of 20.0 μm or more and 75.0 μm or less. By setting the arithmetic mean roughness and maximum height of the separator surface on which the pressure-sensitive adhesive layer is formed within the above ranges, a predetermined uneven structure can be formed on the surface of the pressure-sensitive adhesive layer that contacts the separator, and when a pressure-sensitive adhesive film is attached to a substrate via the pressure-sensitive adhesive layer, air bubbles are less likely to be trapped between the pressure-sensitive adhesive layer and the substrate, making it possible to produce a pressure-sensitive adhesive film in which traces of the uneven structure on the surface of the pressure-sensitive adhesive layer are difficult to see when the decorated molded product is observed from the substrate side.

[0109] If the directions corresponding to the MD, TD, and oblique directions of the resulting film are the MD, TD, and oblique directions of the separator, respectively, the arithmetic mean roughness Ra in any one of the MD, TD, and oblique directions of the separator surface on which the pressure-sensitive adhesive layer is formed (hereinafter also referred to as the separator surface) should be 3.5 μm or more and 14.0 μm or less. Also, the maximum height Rz in any one of the MD, TD, and oblique directions of the separator surface should be 20.0 μm or more and 75.0 μm or less.

[0110] The Ra in the MD direction, Ra in the TD direction, and Ra in the oblique directions on the surface of the separator can be obtained by setting a predetermined reference length along the MD direction, TD direction, and oblique direction of the surface of the separator, respectively, and calculating the average value of Ra in the MD direction, the average value of Ra in the TD direction, and the average value of Ra in the oblique directions measured in any number of measurement areas. The method for calculating Ra and Rz on the surface of the separator can be applied by replacing "the surface of the pressure-sensitive adhesive layer opposite to the resin film side" in the method for calculating Ra and Rz of the pressure-sensitive adhesive film described in embodiment 1 with "the surface of the separator on which the pressure-sensitive adhesive layer is formed."

[0111] The arithmetic mean roughness Ra of the separator surface is more preferably 4.0 μm or more and 14.0 μm or less, and even more preferably 7.0 μm or more. The maximum height Rz of the separator surface is more preferably 60.0 μm or less. From the viewpoint of making the traces of the uneven structure on the surface of the pressure-sensitive adhesive layer 2 less visible and suppressing the air entrapment, it is particularly preferable that the Ra be 7.0 μm or more and 14.0 μm or less, and the Rz be 35.0 μm or more and 60.0 μm or less. It is preferable that the Ra in any one of the MD direction, TD direction, and oblique directions on the separator surface is within the above numerical range of Ra, and it is more preferable that the overall arithmetic mean roughness of the separator surface is within the above numerical range of Ra. It is also preferable that the Rz in any one of the MD direction, TD direction, and oblique directions on the separator surface is within the above numerical range of Rz, and it is more preferable that the overall maximum height of the separator surface is within the above numerical range of Rz.

[0112] The overall arithmetic mean roughness of the separator surface is more preferably 3.5 μm or more and 14.0 μm or less. Furthermore, the overall maximum height of the separator surface is more preferably 20.0 μm or more and 75.0 μm or less. The method for calculating the overall arithmetic mean roughness and overall maximum height of the separator surface can be applied by replacing "the surface of the pressure-sensitive adhesive layer opposite the resin film side" in the method for calculating the overall arithmetic mean roughness and overall maximum height of the pressure-sensitive adhesive film surface described in embodiment 1 with "the surface of the separator on which the pressure-sensitive adhesive layer is formed."

[0113] The standard deviation of the arithmetic mean roughness Ra of the separator surface is preferably 0.3 μm or more and 2.1 μm or less. The standard deviation of the maximum height Rz of the separator surface is preferably 1.5 μm or more and 11.5 μm or less. The method for calculating the standard deviation of the arithmetic mean roughness Ra and the standard deviation of the maximum height Rz of the separator surface can be applied by replacing "the surface of the pressure-sensitive adhesive layer opposite the resin film side" in the method for calculating the standard deviation of the arithmetic mean roughness Ra and the standard deviation of the maximum height Rz of the PSA film described in embodiment 1 with "the surface of the separator on which the PSA layer is formed."

[0114] The pressure-sensitive adhesive layer can be the same as the pressure-sensitive adhesive layer 2 in embodiment 1, and the separator can be the same as the separator in embodiment 3, so a description thereof will be omitted. The uneven structure on the surface of the separator on which the pressure-sensitive adhesive layer is formed can be formed by a known method such as embossing.

[0115] The method for producing a pressure-sensitive adhesive film according to embodiment 4 may include, as in embodiment 3, a step of forming a primer layer on one surface of the resin film prior to the pressure-sensitive adhesive layer lamination step. In this case, in the pressure-sensitive adhesive layer lamination step, it is preferable that the resin film and the pressure-sensitive adhesive layer are laminated via the primer layer. The resin film may be the same as resin film 1 in embodiment 1, and the primer layer may be the same as primer layer 3 in embodiment 1, so further explanation is omitted.

[0116] In embodiment 4, as in embodiment 3, the design layer may be formed on another resin film (second resin film). The method for producing a pressure-sensitive adhesive film according to embodiment 4 may further include, before the pressure-sensitive adhesive layer lamination step, a step of forming a design layer on one side of the other resin film, a film lamination step of laminating the resin film and the other resin film so that the one side of the resin film contacts the design layer, and a step of forming a primer layer on the side of the resin film opposite to the side contacting the design layer. In this case, in the pressure-sensitive adhesive layer lamination step, it is preferable that the resin film and the pressure-sensitive adhesive layer are laminated via the primer layer. The other resin film may be the same as the second resin film 5 of embodiment 2, and therefore further description is omitted.

[0117] An example of a method for producing a resin film according to embodiment 4 will be described below with reference to the drawings, but the method for producing a resin film of the present invention is not limited to the following method. First, a laminate having a primer layer 3, a first resin film 1, a design layer 4, and a second resin film 5 in this order is produced in the same manner as in embodiment 3 shown in FIGS. 4A to 4C.

[0118] FIG. 5A is a cross-sectional view illustrating an example of a pressure-sensitive adhesive layer forming step in the method for producing a resin film according to embodiment 4. FIG. 5B is a cross-sectional view illustrating an example of a pressure-sensitive adhesive layer laminating step in the method for producing a resin film according to embodiment 4. As shown in FIG. 5A, a pressure-sensitive adhesive composition is applied to the surface of separator 30, on which a concavo-convex structure has been formed in advance, to form pressure-sensitive adhesive layer 2. Then, as shown in FIG. 5B, first resin film 1 and pressure-sensitive adhesive layer 2 are laminated such that the surface of pressure-sensitive adhesive layer 2 opposite separator 30 in the structure shown in FIG. 4C faces first resin film 1. The separator is then peeled off to complete pressure-sensitive adhesive film 10 according to the embodiment.

[0119] In embodiment 4, as in embodiment 3, a design layer may be formed on the resin film (first resin film). The method for producing a pressure-sensitive adhesive film according to embodiment 4 may further include, before the pressure-sensitive adhesive layer lamination step, a step of forming a primer layer on one side of the resin film and a design layer on the other side of the resin film. In this case, in the pressure-sensitive adhesive layer lamination step, it is preferable that the resin film and the pressure-sensitive adhesive layer are laminated via the primer layer. The design layer may be the same as design layer 4 in embodiment 2, and therefore further description will be omitted.

[0120] When the design layer is formed on a resin film (first resin film), the method for manufacturing an adhesive film according to embodiment 3 may include, after a step of forming a primer layer on one side of the resin film and forming a design layer on one side of the resin film, a step of laminating the resin film and the other resin film so that the design layer and the other resin film are in contact with each other. [Example]

[0121] The present invention will be explained in more detail below by giving examples, but the present invention is not limited to these examples.

[0122] <Resin film study> The following films were used to investigate resin films suitable for vacuum and pressure forming. Polyvinyl chloride (PVC) film: Bando Chemical Co., Ltd.'s "Viniban," 0.16 mm thick Acrylonitrile-butadiene-styrene copolymer (ABS resin) film: manufactured by Tatsuta Chemical Co., Ltd., thickness 0.41 mm Acrylic film: Kaneka Corporation's "Sunduren 535NAH", thickness 0.075 mm Polyethylene terephthalate (PET) film: Toray Industries, Inc.'s "Lumirror 50T60," 0.08 mm thick

[0123] The polyester-based adhesive A in Table 3 below was applied to the surface of a flat separator (a PET sheet having a thickness of 38 μm) to form a hot-melt adhesive layer having a thickness of 50 μm after drying.

[0124] The breaking strength and breaking elongation of each film laminated with the hot melt pressure-sensitive adhesive layer were measured at test temperatures of 23°C, 80°C, and 100°C. The breaking strength and breaking elongation were measured under the following conditions using a method in accordance with ASTM D882. The results are shown in Table 1 below. Measurement equipment, analysis software, etc.: Shimadzu Corporation's precision universal testing machine Autograph AG-Xplus, video-type non-contact extensometer TRViewx and TRAPENZIUM (software) Pulling speed: 200mm / min Test piece shape: Dumbbell type No. 1 ·Distance between gauge lines: 80mm

[0125] [Table 1]

[0126] A material is suitable for vacuum pressure forming if it has a breaking strength of 30 MPa or less at 100°C and a breaking elongation of 100% or more at 100°C. The results in Table 1 confirm that PVC film, ABS resin film, and acrylic film are suitable, and that PVC film in particular is suitable for vacuum pressure forming because it has good elongation and is resistant to deformation at high temperatures.

[0127] The following PVC films were used to prepare adhesive films in Examples and Comparative Examples. The materials of the PVC films used in the following Examples and Comparative Examples are shown in Table 2 below.

[0128] [Table 2]

[0129] The materials and formulations of the hot-melt pressure-sensitive adhesive compositions used in the pressure-sensitive adhesive layers of the Examples and Comparative Examples are shown in Table 3. The NCO index of the following polyester-based pressure-sensitive adhesives A and B, which are hot-melt pressure-sensitive adhesive compositions, was both 0.8.

[0130] [Table 3]

[0131] Example 1 A vinyl chloride resin composition was prepared according to the formulation shown in Table 4 below. The obtained vinyl chloride resin composition was melt-kneaded in a Banbury mixer and then calendered to produce two 100 μm thick PVC films. The components listed in Table 4 below are the same as those in Table 2 above.

[0132] [Table 4]

[0133] A design layer was printed on one side of one PVC film (second resin film) using ink by gravure printing. The first resin film and the second resin film were bonded together by thermal lamination via the design layer so that the design layer of the second resin film was in contact with the other PVC film (first resin film).

[0134] A primer layer-forming composition (Polyment NK-380, manufactured by Nippon Shokubai Co., Ltd.) was applied to the surface of the first resin film opposite the design layer to form a primer layer containing a monoaminoethylated acrylic polymer. A polyester-based adhesive A in Table 3 was applied as a hot-melt adhesive composition to the surface of a flat separator to form a hot-melt adhesive layer with a dry thickness of 50 μm. A 38 μm-thick PET sheet (38RL-07E, manufactured by Oji F-Tex Co., Ltd.) was used as the separator.

[0135] The primer layer was bonded to the surface of the pressure-sensitive adhesive layer opposite the surface on which the separator was placed, to produce a laminate comprising the separator, primer layer, first resin film, design layer, and second resin film in this order. The laminate was passed through a pair of calendar rolls, including a calendar roll (embossing roll) having the uneven surface structure shown in Table 5 below, with the surface of the embossing roll in contact with the separator, and embossed together with the separator at room temperature. In this specification, the method of embossing together with the separator is also referred to as the simultaneous separator embossing method. The separator was then peeled off, completing the pressure-sensitive adhesive film of Example 1. A cylindrical embossing roll with a circumference of 45 cm was used as the embossing roll.

[0136] (Examples 2 to 7, Comparative Examples 1 to 3) As shown in Tables 5 to 7, except that the surface roughness of the embossing roll was changed, the pressure-sensitive adhesive films of Examples 2 to 6 and Comparative Examples 1 to 3 were produced in the same manner as Example 1. Furthermore, as shown in Tables 5 to 7, except that the surface roughness of the embossing roll and the type of pressure-sensitive adhesive layer were changed, the pressure-sensitive adhesive film of Example 7 was produced in the same manner as Example 1.

[0137] (Measurement of surface roughness of embossing roll) FIG. 6 is a schematic diagram of an embossing roll illustrating the position of the surface roughness measurement area of ​​the embossing roll. The MD, TD, and oblique directions of the embossing roll correspond to the MD, TD, and oblique directions of the PSA film to be formed, respectively. As shown in FIG. 6, the MD direction of the embossing roll is the rotation direction of the embossing roll, the TD direction is the longitudinal direction of the embossing roll, and the oblique direction is a direction forming a 45° angle with the MD and TD directions. As shown in FIG. 6, along the longitudinal direction of the embossing roll, a measurement area for Ra and Rz in the MD direction was set 50 mm from one end of the longitudinal direction of the embossing roll, a measurement area for Ra and Rz in the TD direction was set at the center of the embossing roll, and a measurement area for Ra and Rz in the oblique direction was set 50 mm from the other end of the longitudinal direction of the embossing roll. Each specific area was 50 mm long (length along the longitudinal direction of the embossing roll) and 50 mm wide (length along the rotation direction of the embossing roll). Furthermore, the embossing roll was rotated 50 mm from each of the measurement areas for Ra and Rz in the MD, TD, and oblique directions, and Ra and Rz were measured at five measurement areas in each of the MD, TD, and oblique directions. For each measurement area, the arithmetic mean roughness Ra and maximum height Rz were measured in the MD, TD, and oblique directions.

[0138] The Ra and Rz were measured under the following measurement conditions in accordance with JIS B 0601:2001. Measuring device: Mitutoyo Corporation surface roughness measuring instrument (SURTEST SJ-310), drive detector code No. 178-572-02 Measurement conditions Reference length: 2.5 mm μm Curve: R, Filter: GAUSS, Cutoff value λs: 8 μm, Number of sections: 3, Leading / Late running: ON, Waveform deletion: OFF, Pass / Fail judgment: Average value

[0139] The average value of the five Ra values ​​measured in the five measurement areas and the average value of the maximum height Rz were taken as Ra and Rz values ​​in the MD, TD, and oblique directions of the embossing roll, respectively. Furthermore, the standard deviation was calculated from the 15 total values ​​of Ra and Rz values ​​measured in the five measurement areas in the MD, TD, and oblique directions. Furthermore, the overall arithmetic mean roughness of the embossing roll was calculated from the 15 total values ​​of Ra and Rz values ​​measured in the five measurement areas in the MD, TD, and oblique directions. These values ​​are summarized in Tables 5 to 7 below.

[0140] (Measurement of surface roughness of adhesive layer of adhesive film) FIG. 7 is a schematic diagram illustrating a method for measuring the surface roughness of the adhesive layer of an adhesive film. While peeling off the separator, the adhesive film was rolled up and laid out on a glass plate with the second resin film facing the glass plate and the adhesive layer facing the observer. As shown in FIG. 7, a measurement area for Ra and Rz in the diagonal direction was set 40 mm from one end of the resin film along the flow direction. Further measurement areas for Ra and Rz in the MD direction were set at 40 mm intervals along the TD direction. Further measurement areas for Ra and Rz in the TD direction were set at 40 mm intervals along the TD direction. The size of each measurement area was 20 mm along the TD direction and 20 mm along the MD direction. Measurement areas were set at 20 mm intervals along the flow direction of the resin film from the above-mentioned measurement areas for Ra and Rz in the diagonal direction, the measurement area for Ra and Rz in the MD direction, and the measurement area for Ra and Rz in the TD direction. Ra and Rz were measured in 10 measurement areas in each of the diagonal direction, the MD direction, and the TD direction. The Ra and Rz were measured using the same device and method as in the measurement of the surface roughness of the embossing roll.

[0141] The average values ​​of Ra measured in the MD, TD, and oblique directions in the 10 measurement regions were taken as the Ra of the pressure-sensitive adhesive layer in the MD, TD, and oblique directions. The average values ​​of Rz measured in the 10 measurement regions in the MD, TD, and oblique directions were taken as the maximum height Rz of the pressure-sensitive adhesive layer in the MD, TD, and oblique directions. The overall arithmetic mean roughness and standard deviation of Ra of the pressure-sensitive adhesive layer were calculated from a total of 30 values ​​of Ra measured in the 10 measurement regions in the MD, TD, and oblique directions. The overall maximum height and standard deviation of Rz of the pressure-sensitive adhesive layer were calculated from a total of 30 values ​​of Rz measured in the 10 measurement regions in the MD, TD, and oblique directions. These values ​​are summarized in Tables 5 to 7 below.

[0142] (Evaluation of air entrapment) Ten decorated molded articles were produced from each of the adhesive films of the examples and comparative examples by vacuum and pressure forming. The separator was peeled off from each adhesive film, and the adhesive layer was placed facing the transparent substrate. Vacuum and pressure forming was performed at a forming temperature of 125°C to produce a decorated molded article in which the adhesive film was attached to the transparent substrate. Vacuum and pressure forming was performed using a TOM molding machine (NGF-0406-T) manufactured by Fuse Vacuum Co., Ltd. A glass substrate measuring 6 mm thick, 40 mm long, and 20 mm wide was used as the transparent substrate.

[0143] The resulting decorated molded article was left standing in a room with a fluorescent lamp turned on, and the presence or absence of air bubbles was visually observed from the transparent substrate side. 2 The number of decorated molded articles (out of 10) in which no bubbles were found are shown in Tables 5 to 7 below.

[0144] (Imprint of uneven structure on the adhesive layer surface) Decorative molded articles prepared in the same manner as in the evaluation of air entrapment described above were placed in a room with the fluorescent lights on, and the entire surface (40 mm x 20 mm) of the decorative molded article was visually observed from the transparent substrate side. The number of decorative molded articles (out of 10) for which no traces of the uneven structure on the surface of the adhesive layer were visible through the transparent substrate is shown in Tables 5 to 7 below.

[0145] [Table 5]

[0146] [Table 6]

[0147] [Table 7] [Explanation of symbols]

[0148] 1: Resin film (first resin film) 2: Adhesive layer 3: Primer layer 4: Design layer 5: Other resin film (second resin film) 10: Adhesive film 20: Base material 30: Separator 100: Decorative molding

Claims

[Claim 1] A film having a resin film and a pressure-sensitive adhesive layer, The pressure-sensitive adhesive film has a surface of the pressure-sensitive adhesive layer opposite to the resin film side, the surface having an arithmetic mean roughness of 3.5 μm or more and 14.0 μm or less, and a maximum height of 20.0 μm or more and 75.0 μm or less.

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