Colored film, colored adhesive tape and method for producing colored film

Abstract

To provide a colored film excellent in designability and alcohol resistance due to mat tone, and excellent in fire retardancy, and to provide a colored adhesive tape.SOLUTION: The present invention provides a colored film that has a concave-convex shape on one surface and contains a coloring agent in a resin film, which demonstrates VTM-2 or higher in flammability tests according to the UL 94 VTM method (ISO 9773 1998), has a 60° gloss value within a specified range, and / or has an arithmetic average roughness of the concave-convex surface of the resin film within a specified range.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a colored film and a colored adhesive tape comprising the colored film and an adhesive layer provided on the colored film. [Background technology]

[0002] In the field of electronic devices such as office automation equipment, home appliances, and mobile devices, colored films are used to protect the components inside. Since the inclusion of foreign matter inside electronic devices can cause short circuits and malfunctions, colored films used inside electronic devices are often wiped with alcohol to remove foreign matter when they are attached to components, and therefore alcohol resistance is required.

[0003] For example, Patent Document 1 discloses a colored film having a colored layer (ink layer) formed on a resin film using a colored ink, and a matte layer provided on the colored layer (ink layer), and alcohol resistance is achieved by setting the glass transition temperature of the resin in the colored layer (ink layer) within a predetermined range.

[0004] [Patent Document 1] Japanese Patent Publication No. 2022-100696 DISCLOSURE OF THE INVENTION [Problem to be solved by the invention]

[0005] In addition to protecting components, colored films are required to have excellent matte finish designs to conceal defects (such as unevenness and small imperfections) on the components' appearance and improve their appearance. However, even if a matte layer is applied to an ink layer by applying a paint containing a matting agent or by sandblasting to enhance the matte finish of the colored film, the gloss value exhibited by the matte layer changes when the film is wiped with alcohol, resulting in the disappearance of the matte finish, and the desired design may not be achieved. Furthermore, with conventional matte layers, it is difficult to significantly reduce the gloss value that contributes to the matte finish. Furthermore, colored films used around the batteries of electronic devices are required to be flame-retardant, but the ink and matte layers of the colored film easily burn, making it difficult to achieve flame retardancy.

[0006] The present invention provides a colored film that is flame retardant, has a high designability due to its matte finish, and has excellent alcohol resistance, and also provides a colored pressure-sensitive adhesive tape that includes the colored film. [Means for solving the problem]

[0007] As a result of intensive research into achieving the above-mentioned object, the inventors have found that the object of the present invention can be achieved by a colored film having a resin film with an uneven shape of a specific surface roughness and containing a colorant, and an adhesive tape using said film, and have thus completed the present invention.

[0008] The present invention has the following aspects.

[0009] [1] A colored film having a resin film containing a colorant, the resin film having an uneven shape on one side, a 60° gloss value of 4 or less, and exhibiting VTM-2 or higher in a flammability test in accordance with the UL94 VTM method (ISO9773 1998). [2] The colored film according to [1], wherein the surface of the resin film having the irregular shape has an arithmetic mean roughness of 0.9 μm or more and 6.0 μm or less. [3] A colored film having a resin film containing a colorant, the resin film having an uneven surface on one side, the arithmetic mean roughness of the uneven surface of the resin film being 0.9 μm or more and 6.0 μm or less, and exhibiting VTM-2 or higher in a flammability test in accordance with the UL94 VTM method (ISO9773 1998). [4] The colored film according to any one of [1] to [3], which is composed of a single layer of the resin film. [5] The colored film according to any one of [1] to [4], wherein the resin film has the uneven shape formed on the one surface. [6] The colored film according to any one of [1] to [5], wherein the resin film is a polycarbonate film. [7] The colored film according to any one of [1] to [6], wherein L* is 20 to 29, a* is -1 to 1, and b* is -2 to 0 in the CIE Lab color system. [8] The colored film according to any one of [1] to [7], wherein the ten-point average roughness Rz of the surface of the resin film having the irregular shape is 5.0 μm or more and 40.0 μm or less. [9] The colored film according to any one of [1] to [8], wherein the content of the colorant in the resin film is 0.5% by mass or more and 5% by mass or less.

[10] An adhesive tape comprising the colored film according to any one of [1] to [9], and an adhesive layer on the surface opposite to the surface of the resin film having the irregular shape.

[11] The pressure-sensitive adhesive tape according to

[10] , wherein the pressure-sensitive adhesive layer contains a flame retardant.

[12] The adhesive tape according to

[10] or

[11] , which exhibits VTM-2 or higher in a flammability test in accordance with the UL94VTM method (ISO9773 1998).

[13] A method for producing a colored film according to any one of [1] to [9], comprising a step of transferring the surface shape of a shaping plate onto one side of a resin film containing a colorant to form a concave-convex shape.

[14] The method for producing a colored film according to

[13] , wherein the surface shape of the shaped plate satisfies at least one of the following (1) or (2): (1) The arithmetic mean roughness Ra is 0.6 μm or more and 5.0 μm or less. (2) The ten-point average roughness Rz is 4.0 μm or more and 35.0 μm or less. [Effects of the Invention]

[0010] The colored film and colored pressure-sensitive adhesive tape of the present invention have excellent designability due to their matte finish and alcohol resistance, and also exhibit high flame retardancy. Therefore, the colored film and colored pressure-sensitive adhesive tape of the present invention can be suitably used for protecting components of electronic devices equipped with batteries, which require high flame retardancy. [Brief explanation of the drawings]

[0011] [Figure 1] 1 is a schematic cross-sectional view showing an example of the colored film of the present invention. [Figure 2] 1 is a schematic cross-sectional view showing an example of the colored pressure-sensitive adhesive tape of the present invention. DETAILED DESCRIPTION OF THE INVENTION

[0012] I. Colored film The colored film of the present invention has a resin film containing a colorant, and the resin film has an uneven shape on one surface. The colored film of the present invention exhibits VTM-2 or higher in a flammability test in accordance with the UL94 VTM method (ISO9773 1998).

[0013] The colored film of the present invention exhibits VTM-2 or higher in a flammability test in accordance with the UL94 VTM method (ISO9773 1998). That is, the colored film of the present invention passes the standards of VTM-2 to VTM-0 in a flammability test in accordance with the UL94 VTM method (ISO9773 1998). Of these, VTM-1 or higher is preferred, and VTM-0 is particularly preferred. The UL94 VTM test is a test conducted in accordance with ISO9773 1998. When the colored film of the present invention consists of a single layer of resin film, the flame retardancy of the colored film means the flame retardancy of the resin film.

[0014] The colored film of the present invention has a gloss value at an incident angle of 60° of 4 or less. When the gloss value at an incident angle of 60° of the colored film is within the above range, the low gloss value results in an excellent matte finish, a luxurious feel, and a colored film with high designability. The lower the gloss value at an incident angle of 60° of the colored film, the better the matte finish, and 0 is most preferable. The gloss value at an incident angle of 60° of the colored film is preferably 3.5 or less, and more preferably 0.5 or more and 3.0 or less. When the colored film of the present invention consists of a single layer of resin film, the gloss value at an incident angle of 60° mentioned above is, in other words, the gloss value of the single layer of resin film at an incident angle of 60°.

[0015] The gloss value at an incident angle of 60° is the average value of values measured at any 10 points on the surface of the colored film located on the uneven surface side of the resin film (the uneven surface of the colored film) using a glossmeter (MINOLTA Multi-Gloss 268 manufactured by KONICA MINOLTA) in accordance with measurement standard JIS Z 8741. When the colored film consists of a single layer of resin film, the average value is the average value of values measured at any 10 points on the uneven surface of the resin film.

[0016] In the colored film of the present invention, it is preferable that the uneven surface of the resin film constitutes one surface of the colored film. That is, it is preferable that one surface of the colored film has an uneven shape. The details of the uneven shape of one surface of the colored film can be the same as the details of the uneven surface of the resin film.

[0017] The colored film of the present invention has at least a resin film having a textured surface and is provided with the desired physical properties. It may be in the form of a single layer of resin film or a laminate including a resin film and another layer. When the colored film has a layer other than the resin film, the other layer is preferably provided on the surface opposite the textured surface of the colored film so as not to impair the matte finish provided by the textured surface of the resin film. Examples of the other layer include a support layer. Furthermore, since the matte finish can be provided by the resin film, the colored film of the present invention does not need to include a separate matte layer on the resin film. In particular, the colored film is preferably composed of a single layer of the resin film. Furthermore, as described below, it is preferable for the resin film to have a textured surface directly formed on one surface, from the viewpoints of achieving both designability due to the textured surface, alcohol resistance, and flame retardancy. FIG. 1 is a schematic cross-sectional view showing an example of the colored film of the present invention, showing an example in which the colored film 10 is made of a single layer of resin film 1, and one side of the colored film 10 (resin film 1) shown in FIG. 1 has an uneven surface formed by direct molding.

[0018] (resin film) The colored film of the present invention has a resin film having an uneven shape on one surface and containing a colorant. The color of the resin film is not particularly limited, and may be an achromatic color such as black, white, or gray, or a chromatic color such as red, blue, or yellow. It may also be a metallic color such as silver or a pearl color. Among these, the color of the resin film is preferably black or white because it can exhibit high hiding power and can create a sense of unity with the colors of other components when used, for example, within electronic components. The color of the colored film (the color of the surface of the colored film in a plan view from the surface facing the uneven surface of the resin film) can be selected depending on the color of the resin film, and black or white is particularly preferred.

[0019] The arithmetic mean roughness of the surface of the resin film having the uneven shape (hereinafter sometimes referred to as the uneven surface of the resin film) is preferably 0.9 μm or more and 6.0 μm or less. When the arithmetic mean roughness of the uneven surface of the resin film is within the above range, the gloss value can be reduced (60° gloss value can be reduced to 4 or less), thereby achieving an excellent matte finish. In addition, alcohol resistance can be achieved, and the matte finish can be prevented from being damaged by wiping. The arithmetic mean roughness of the uneven surface is more preferably in the range of 1.0 μm or more and 5.0 μm or less, and even more preferably 2.0 μm or more and 4.0 μm or less.

[0020] The ten-point average roughness Rz of the uneven surface of the resin film is preferably 7.0 μm or more and 40.0 μm or less. When the ten-point average roughness Rz of the uneven surface of the resin film is in the above range, the gloss value can be reduced, an excellent matte finish can be achieved, and alcohol resistance can be exhibited. The ten-point average roughness Rz of the uneven surface is more preferably in the range of 8.0 μm or more and 30.0 μm or less, and even more preferably 15.0 μm or more and 25.0 μm or less.

[0021] The uneven surface of the resin film preferably has at least an arithmetic mean roughness within the above range, and more preferably has both an arithmetic mean roughness and a ten-point mean roughness Rz within the above range.

[0022] The arithmetic mean roughness Ra and the ten-point mean roughness Rz are determined by measuring the surface of the uneven surface of a resin film at any three points using an Olympus OLS4100 in accordance with the provisions of JIS B0601:2013, and taking the average values of the three points obtained by the measurements.

[0023] The uneven surface of the resin film can be formed, for example, by directly forming unevenness on the surface of the resin film, by incorporating a filler or the like and causing the filler to protrude from the surface of the resin film to form an uneven shape, or by sandblasting the resin film to form an uneven shape on the surface. Among these, it is preferable that the resin film has an uneven shape formed on one side. "Having an uneven shape formed on one side of the resin film" refers to the surface (flat surface) of the resin film itself being deformed to form an uneven shape by pressing with a mold, cutting, or the like, and this is also referred to as "directly formed." By directly forming an uneven shape on the surface of the resin film, deformation of the uneven shape due to wiping with alcohol can be suppressed compared to when an ink layer or matte layer is provided, and the matte finish can be prevented from being damaged. In particular, as described below, when the resin film is a polycarbonate film, it has high durability against alcohol and high flame retardancy, and therefore alcohol resistance, designability, and flame retardancy can be achieved simultaneously.

[0024] The resin film contains a resin as a main component. Specifically, the resin content in the resin film can be 50% by mass or more, particularly 70% by mass or more, more preferably 80% by mass or more, and even more preferably 90% by mass or more. The upper limit of the resin content in the resin film can be appropriately set depending on the content of the colorant and other optional components, but can be, for example, 99.5% by mass or less, or 95% by mass or less.

[0025] Specific examples of the resin film include polycarbonate films, polyester films, polyethylene films, polypropylene films, cellulose films such as triacetyl cellulose, polyvinyl chloride films, polyvinylidene chloride films, polyvinyl alcohol films, ethylene-vinyl acetate copolymer films, polystyrene films, acrylic resin films, norbornene-based resin films, and cycloolefin resin films; laminates of two or more of these films; etc. The resin film may be uniaxially or biaxially stretched.

[0026] Among these, polycarbonate films are preferred because of their excellent flame retardancy and shaping properties, as well as their excellent alcohol resistance. Polycarbonate films exhibit high flame retardancy regardless of whether or not they contain a flame retardant due to the physical properties of the resin. Furthermore, because polycarbonate films are soft, they are easy to form unevenness into, allowing the gloss value to be adjusted low depending on the uneven shape. The uneven shape can be stably maintained even when wiped with alcohol. Therefore, a high level of designability can be achieved through a matte finish.

[0027] Polycarbonate films include various types, and two or more of them may be used in combination. Examples of polycarbonates constituting polycarbonate films include polymers obtained by the phosgene method, in which a dihydroxy compound is reacted with phosgene, and polymers obtained by the transesterification method, in which a dihydroxy compound is reacted with a carbonate ester such as diphenyl carbonate. Among these, aromatic polycarbonate resins are preferred. Examples of aromatic polycarbonate resins include polymers obtained by the phosgene method using a dihydroxydiaryl compound as the dihydroxy compound, and polymers obtained by the transesterification method using a dihydroxydiaryl compound as the dihydroxy compound.

[0028] More specifically, preferred examples of the polycarbonate include polycarbonates synthesized by transesterification or the phosgene method using one or more bisphenol components, such as 4,4'-dihydroxydiphenylalkanes such as 2,2'-bis(4-hydroxyphenyl)propane (hereinafter referred to as bisphenol A) and 2,2'-bis(4-hydroxyphenyl)methane (hereinafter referred to as bisphenol F), 4,4'-dihydroxydiphenyl sulfone (hereinafter referred to as bisphenol S), and 4,4'-dihydroxydiphenyl ether. Of these, 2,2'-bis(4-hydroxyphenyl)alkane-based polycarbonates using bisphenol A or the like are particularly suitable.

[0029] The viscosity average molecular weight of the polycarbonate resin is within a range of 10,000 to 50,000, and preferably within a range of 20,000 to 40,000. When the viscosity average molecular weight of the polycarbonate resin is within the above range, the resulting polycarbonate film can achieve both high film strength and high-precision shaping onto the film surface.

[0030] When the resin film is a polycarbonate film, the resin film may contain other resins in addition to the polycarbonate resin, as long as the properties of the polycarbonate film are not impaired. Examples of other resins include thermoplastic polyester resins such as polyethylene terephthalate (PET) and polybutylene terephthalate (PBT); styrene-based resins such as polystyrene resin, high-impact polystyrene resin (HIPS), and acrylonitrile-styrene copolymer (AS resin); polyolefin resins such as polyethylene resin and polypropylene resin; polyamide resin; polyimide resin; polyetherimide resin; polyurethane resin; polyphenylene ether resin; polyphenylene sulfide resin; polysulfone resin; polymethacrylate resin; and various elastomers.

[0031] The resin film preferably contains 80% by mass or more of polycarbonate resin in the resin constituting the resin film, more preferably 90% by mass or more, and it is particularly preferable that the polycarbonate resin content be substantially 100% by mass, since this allows for flame retardancy, the uneven shape to be precisely formed, and the uneven shape to be stably maintained.

[0032] (coloring agent) The resin film contains one or more colorants, and the colorants can be selected from pigments and dyes depending on the color of the resin film and the colored film. Examples of the colorants include black colorants such as carbon black and aniline black, white colorants such as titanium oxide, calcium carbonate, and barium sulfate, yellow colorants such as yellow iron oxide, red colorants such as red iron oxide, blue colorants such as cyanine blue, silver colorants such as aluminum powder, and pearl colorants such as mica titanium powder, all of which are preferred in terms of weather resistance, heat resistance, and dispersibility. Among these, black or white colorants are preferred, and carbon black is more preferred among black colorants due to its excellent hiding power.

[0033] The content of the colorant in the resin film is not particularly limited as long as it can achieve the desired color tone, but is, for example, preferably 0.5% by mass to 5% by mass, more preferably 1% by mass to 3% by mass. When the content of the colorant in the resin film is within the above range, it is possible to achieve a high level of both flame retardancy and designability due to color (for example, blackness).

[0034] (Flame retardant) The resin film preferably contains a flame retardant. When the resin film is a polycarbonate film, the polycarbonate film can exhibit flame retardancy due to its own properties, so it is not essential to contain a flame retardant, but it is preferable to contain a flame retardant because this allows the polycarbonate film to exhibit higher flame retardancy.

[0035] Flame retardants can be materials commonly used in plastic films, such as silicone compounds, hydrated metal compounds, phosphorus compounds, nitrogen-containing compounds, halogen-containing compounds, metal oxides, borate compounds, tin compounds, and organic carboxylic acid compounds. Silicone compounds include high-molecular-weight silicone oils, silicone polymers, and fumed silica. Hydrated metal compounds include aluminum hydroxide and magnesium hydroxide. Phosphorus compounds include red phosphorus, ammonium polyphosphate, guanidinium phosphate, phosphate esters, triethyl phosphate, tributoxyethyl phosphate, tricresyl phosphate, triphenyl phosphate, and tris(2,3-dichloropropyl phosphate). Halogen-containing compounds include hexabromobenzene and hexabromododecane. Nitrogen-containing compounds include urea and its compounds, melamine compounds, and guanidine compounds. Metal oxides include zinc oxide, tin oxide, iron oxide, and copper oxide. Specific examples of boric acid compounds include borate salts such as zinc borate, boric acid oxide, etc. Specific examples of tin compounds include zinc stannate, etc. Specific examples of organic carboxylic acid compounds include tetrabromophthalic anhydride, chlorendo acid, etc. Flame retardants may be used alone or in combination of two or more. Of these, phosphorus-based compounds or halogen-containing compounds are preferred as flame retardants, with phosphorus-based compounds being more preferred. Among phosphorus-based compounds, ammonium polyphosphate is even more preferred because it can form a carbonized layer to further improve flame retardancy.

[0036] The content of the flame retardant in the resin film is preferably in the range of 0.1 to 80 parts by mass, more preferably in the range of 1 to 50 parts by mass, and even more preferably in the range of 5 to 30 parts by mass, per 100 parts by mass of the resin constituting the resin film. By having the content of the flame retardant in the resin film in the above range, the resin film can exhibit high flame retardancy while maintaining the desired formability.

[0037] (Flame retardant synergist) The resin film may contain a flame retardant aid to enhance flame retardancy. Known flame retardant aids can be used, such as antimony trioxide, aromatic sulfonates having 6 to 30 carbon atoms, fluorine-substituted aliphatic sulfonates having 3 to 30 carbon atoms, and aliphatic sulfates having 8 to 30 carbon atoms. The content of the flame retardant aid in the resin film is not particularly limited, and can be within a range of 0.001% by mass to 1% by mass.

[0038] (Matte agent) Since the resin film has a predetermined uneven surface, the desired effect can be achieved without containing a matting agent, but a matting agent may be contained. This is because, in addition to the matte finish produced by the uneven surface, the matte finish can be further enhanced by the matting agent. Known and commonly used materials can be used as the matting agent, such as talc, silica, polyethylene wax, calcium carbonate, barium sulfate, and various metal fillers. Among these, talc is most preferred from the viewpoint of achieving both insulation properties and a matte finish.

[0039] The content of the matting agent in the resin film is preferably in the range of 0 to 10 parts by mass, more preferably in the range of 1 to 7 parts by mass, and even more preferably in the range of 3 to 5 parts by mass, relative to 100 parts by mass of the resin constituting the resin film. By having the content of the matting agent in the resin film in the above range, it is possible to achieve both flame retardancy and a matte finish to an even higher degree.

[0040] The resin film may contain additives such as a light stabilizer and an antioxidant in addition to the materials mentioned above.

[0041] (resin film) The surface of the resin film opposite to the textured surface may be subjected to a conventional surface treatment, for example, oxidation treatment by a chemical or physical method such as chromic acid treatment, ozone exposure, flame exposure, high-voltage shock exposure, or ionizing radiation treatment, or may be subjected to a coating treatment with a primer, etc. When another layer is provided on the surface of the resin film opposite to the textured surface, adhesion can be improved.

[0042] The thickness of the resin film is not particularly limited as long as it has the desired required properties, but is preferably 25 μm to 300 μm, more preferably 50 μm to 200 μm, and even more preferably 75 μm to 150 μm. The thickness of the resin film is the average value of thickness measurements taken at 10 arbitrary locations, including both the concave and convex portions of the uneven surface, using a Nikon Digimicro MF-501, MCF-101, or MS-31G with a φ5 mm measuring probe to 0.1 μm increments.

[0043] The ratio (Ra / T) of the arithmetic mean roughness (Ra) to the thickness (T) of the resin film is preferably 0.001 or more and 0.3 or less, more preferably 0.005 or more and 0.1 or less, and even more preferably 0.01 or more and 0.08 or less. The ratio (Rz / T) of the ten-point mean roughness (Rz) to the thickness (T) of the resin film is preferably 0.01 or more and 0.8 or less, more preferably 0.05 or more and 0.6 or less, and even more preferably 0.1 or more and 0.5 or less. When at least one of Ra / T and Rz / T is within the above range, it is possible to achieve both a low gloss value due to the uneven shape of the resin film surface and flame retardancy of the resin film. If Ra / T and / or Rz / T are too small, it is difficult to obtain the desired gloss value, while if Ra / T and / or Rz / T are too large, the depressions in the uneven shape will be too deep, shortening the length of the region (base) from the tip of the depression to the surface of the resin film opposite the uneven surface, thereby reducing the flame retardancy of the resin film.

[0044] The hue of the above resin film in the CIE Lab color system (L * value, a * value, b * The L value of the resin film is not particularly limited and can be set independently and appropriately depending on the required design, shielding properties, etc. * The value of a of the resin film is preferably 20 or more and 36 or less, and more preferably 22 or more and 30 or less. * The value is preferably −3 or more and 3 or less, and more preferably −1 or more and 1 or less. *The value is preferably −3 or more and 3 or less, and more preferably −2 or more and 0 or less. * value, a * value, b * The color value) was measured from the textured surface side of the resin film using a spectrophotometer (CM-5, manufactured by Konica Minolta, Inc.) in accordance with the measurement standard JIS Z 8722, with a C spectrum of 10°.

[0045] The total light transmittance of the resin film is preferably 10% or less, more preferably 3% or less, and even more preferably 1% or less, from the viewpoint of ensuring design, concealment, and light-blocking properties. The total light transmittance is the total light transmittance Tt measured in accordance with JIS K7105.

[0046] (Method of manufacturing resin film) The method for producing the resin film is not particularly limited as long as it can form a predetermined uneven surface, but it is preferable to include a step of transferring the surface shape of a shaping plate to one side of a resin film containing a colorant to form an uneven shape. More specifically, it is preferable to form a resin composition containing at least a resin and a colorant into a film, and then transfer the surface shape of a shaping plate to one side of the formed film to form an uneven shape. By transferring the uneven shape to the formed film using a shaping plate, an uneven shape is formed on the film surface, so that unevenness can be formed with higher precision than when an uneven shape is formed using a filler or sandblasting. In addition, the uneven shape is less likely to deform when wiped with alcohol, which can suppress an increase in gloss value and provide a matte finish.

[0047] The method of forming into a film is not particularly limited, and examples thereof include melt extrusion molding, solvent casting, etc. Among these, the melt extrusion molding method is preferred because it has high productivity and can produce a wide range of thicknesses, and among the melt extrusion molding methods, the T-die molding method and the inflation molding method are more preferred. In addition, the method of forming a concave-convex shape on the film is not particularly limited, but it is preferred to use a roll with a concave-convex shape as a forming plate.

[0048] The arithmetic mean roughness Ra of a roll having an uneven surface is preferably 0.6 μm or more and 5.0 μm or less. By setting the arithmetic mean roughness Ra of the roll within the above range, the 60° gloss value of the film can be adjusted to a predetermined value or less (particularly 4 or less), making it easier to balance productivity. Ra is more preferably 2.0 μm or more and 4.0 μm or less. Furthermore, the ten-point mean roughness Rz of the roll is preferably 4.0 μm or more and 35.0 μm or less. By setting the mean roughness Rz of the roll within the above range, the 60° gloss value of the film can be adjusted to a predetermined value or less (particularly 4 or less), making it easier to balance thickness accuracy of the film. In particular, Rz is more preferably 10.0 μm or more and 25.0 μm or less.

[0049] The following describes a specific method for producing a resin film, using a polycarbonate film as an example. Polycarbonate chips, either dried or undried by a known method, are fed into a kneading extruder, optionally with a lubricant, color pigment, or a masterbatch containing a high concentration of color pigment, and heated to a temperature above the melting point of the polycarbonate component to melt it. The molten polycarbonate resin is then extruded through a die and rapidly solidified on a rotating cooling roll, yielding a substantially amorphous, unoriented sheet.

[0050] By using a rotating cooling roll with an uneven surface, an uneven surface can be formed on the resin film. In this case, lamination using a nip roll is preferable. Alternatively, an uneven surface can be formed on both sides of the film by forming an uneven surface on the nip roll.

[0051] The arithmetic mean roughness Ra of a roll having an uneven surface is preferably 0.6 μm or more and 5.0 μm or less. By setting the arithmetic mean roughness Ra of the roll within the above range, the 60° gloss value of the film can be adjusted to a predetermined value or less (particularly 4 or less), making it easier to balance productivity. Ra is more preferably 2.0 μm or more and 4.0 μm or less. Furthermore, the ten-point mean roughness Rz of the roll is preferably 4.0 μm or more and 35.0 μm or less. By setting the mean roughness Rz of the roll within the above range, the 60° gloss value of the film can be adjusted to a predetermined value or less (particularly 4 or less), making it easier to balance thickness accuracy of the film. In particular, Rz is more preferably 10.0 μm or more and 25.0 μm or less.

[0052] (colored film) The hue (L * value, a * value, b * The L value of the colored film of the present invention is not particularly limited and can be appropriately set independently depending on the required design, shielding property, etc. * The value is preferably 20 or more and 36 or less, and more preferably 22 or more and 30 or less. * The value is preferably −3 or more and 3 or less, and more preferably −1 or more and 1 or less. * The value is preferably −3 or more and 3 or less, and more preferably −2 or more and 0 or less. * value, a * value, b * The color value) was measured using a spectrophotometer (CM-5, manufactured by Konica Minolta, Inc.) in accordance with the measurement standard JIS Z 8722, where the C spectrum is 10°, from the side of the surface of the colored film that has the uneven shape of the resin film.

[0053] The thickness of the colored film of the present invention is not particularly limited, but is preferably 12 μm or more and 2000 μm or less. When the thickness of the colored film is within the above range, it is easy to achieve both flame retardancy and film strength. A more preferred range for the thickness of the colored film is 50 μm or more and 300 μm or less, and even more preferably 75 μm or more and 150 μm or less. When the colored film of the present invention consists of a single layer of resin film, the thickness of the colored film is, in other words, the thickness of the resin film.

[0054] From the viewpoint of ensuring design, concealment, and light-shielding properties, the colored film of the present invention preferably has a total light transmittance of 10% or less, more preferably 3% or less, and most preferably 1% or less. The total light transmittance is the total light transmittance Tt measured in accordance with JIS K7105.

[0055] The colored film of the present invention can be used to protect electronic components from the viewpoints of flame retardancy, design, etc. Specifically, the colored film of the present invention can be suitably used to protect circuit components in electronic devices, and can be used as a colored film for protecting electronic circuit components.

[0056] II. Colored adhesive tape The colored adhesive tape of the present invention has a pressure-sensitive adhesive layer on the surface of the colored film described above in the section "I. Colored Film" that is opposite to the surface of the resin film having the uneven shape. The pressure-sensitive adhesive layer is provided on the surface of the resin film that is opposite to the surface having the uneven shape directly or via another layer.

[0057] Fig. 2 is a schematic cross-sectional view showing an example of the colored adhesive tape of the present invention. As illustrated in Fig. 2, the colored adhesive tape 20 of the present invention has a colored film 10 having a resin film layer 1, and an adhesive layer 11. The colored adhesive tape 20 has an adhesive layer 11 on one of surfaces 10a and 10b of the colored film 10, which is located opposite to surface 10a located on the uneven surface side of the resin film layer 1 (the uneven surface of the colored film 10 in Fig. 2). In Fig. 2, the uneven surface 10a of the resin film 10 constitutes one surface 20a of the colored adhesive tape 20. That is, the colored adhesive tape 20 illustrated in Fig. 2 has an uneven surface 20a and an adhesive surface 20b opposite to surface 20a with the uneven surface.

[0058] The colored adhesive tape of the present invention has a high designability and excellent alcohol resistance due to the presence of the colored film described above, and furthermore, when applied to a flame-retardant or non-flammable adherend, it can ensure flame retardancy in the applied state. The flame retardancy level of the adherend is not particularly limited, but it is preferable that the adherend exhibits VTM-2 or higher in a flammability test in accordance with the UL94 VTM method (ISO9773 1998).

[0059] The colored adhesive tape of the present invention has the colored film described above in the section "I. Colored Film," and therefore can exhibit flame retardancy when attached to a flame-retardant or non-flammable adherend, but it is preferable that the colored adhesive tape itself exhibits flame retardancy. The colored adhesive tape of the present invention preferably exhibits VTM-2 or higher, more preferably VTM-1 or higher, and more preferably VTM-0, in a flammability test in accordance with the UL94 VTM method (ISO9773 1998).

[0060] The adhesive strength of the colored adhesive tape of the present invention is preferably in the range of 5 N / 25 mm to 60 N / 25 mm, more preferably in the range of 10 N / 25 mm to 50 N / 25 mm, and even more preferably in the range of 15 N / 25 mm to 45 N / 25 mm. If the adhesive strength of the colored adhesive tape of the present invention is too low, it will easily peel off from the adherend, and if it is too high, it will be difficult to remove during rework. The adhesive strength of the colored adhesive tape is the 180° peel adhesive strength measured in accordance with JIS Z0237-2000, and is the adhesive strength when the colored adhesive tape is applied to a stainless steel plate in an environment of 23°C and 50% RH and peeled off at a peeling rate of 300 mm / min after 1 hour.

[0061] [Colored film] Details of the colored adhesive tape of the present invention are the same as those explained in the above section "I. Colored Film," and therefore will not be explained here.

[0062] [Adhesive layer] The thickness of the adhesive layer in the colored adhesive tape of the present invention may be any thickness that allows the desired adhesive strength to be exhibited, and is preferably in the range of 5 μm to 100 μm, more preferably in the range of 10 μm to 80 μm, and even more preferably in the range of 20 μm to 70 μm. By making the thickness of the adhesive layer 5 μm or more, suitable adhesiveness can be achieved, and by making the thickness 100 μm or less, suitable thinness can be achieved. Furthermore, when the colored adhesive tape of the present invention is applied to a flame-retardant or non-flammable adherend, the adhesive layer is sandwiched between the colored film and the flame-retardant or non-flammable adherend, so that the progression of combustion in the adhesive layer is inhibited regardless of whether the adhesive layer has flame retardancy, thereby improving the flame retardancy of the colored adhesive tape.

[0063] The adhesive forming the adhesive layer is not particularly limited and can be appropriately selected from known adhesives such as acrylic adhesives, rubber adhesives, silicone adhesives, urethane adhesives, polyester adhesives, styrene-diene block copolymer adhesives, vinyl alkyl ether adhesives, polyamide adhesives, fluorine-based adhesives, creep-improved adhesives, and radiation-curable adhesives. The adhesives can be used alone or in combination of two or more. Depending on the type, various adhesives contain one or more rubber-like polymers, such as acrylic polymers, rubber polymers, polyester polymers, urethane polymers, polyether polymers, silicone polymers, polyamide polymers, and fluorine-based polymers, as the base polymer. The term "base polymer" refers to the main component of the polymer components contained in the adhesive, e.g., a component that accounts for more than 50% by mass.

[0064] Among these, acrylic adhesives are preferred because of their high adhesive reliability. Acrylic adhesives contain an acrylic polymer as a base polymer.

[0065] The acrylic polymer is a polymer (copolymer) whose main monomer component is a (meth)acrylic acid alkyl ester, and is prepared by using a monomer (copolymerizable monomer) that can be copolymerized with the (meth)alkyl ester as needed. Examples of the (meth)acrylic acid alkyl ester include methyl (meth)acrylate, ethyl (meth)acrylate, propyl (meth)acrylate, isopropyl (meth)acrylate, butyl (meth)acrylate, isobutyl (meth)acrylate, s-butyl (meth)acrylate, t-butyl (meth)acrylate, pentyl (meth)acrylate, hexyl (meth)acrylate, heptyl (meth)acrylate, octyl (meth)acrylate, 2-ethylhexyl (meth)acrylate, isooctyl (meth)acrylate, nonyl (meth)acrylate, isononyl (meth)acrylate, Examples of suitable acrylic polymers include C1-20 alkyl (meth)acrylates (preferably C4-18 alkyl (straight-chain or branched-chain) (meth)acrylates), such as decyl (meth)acrylate, isodecyl (meth)acrylate, undecyl (meth)acrylate, dodecyl (meth)acrylate, tridecyl (meth)acrylate, tetradecyl (meth)acrylate, pentadecyl (meth)acrylate, hexadecyl (meth)acrylate, heptadecyl (meth)acrylate, octadecyl (meth)acrylate, nonadecyl (meth)acrylate, and eicosyl (meth)acrylate. The alkyl methacrylate ester can be appropriately selected depending on the desired adhesiveness. The alkyl methacrylate esters can be used alone or in combination of two or more. Among these, acrylic polymers containing butyl acrylate in an amount of 90% by mass or more of the monomer components constituting the acrylic polymer are preferred due to their excellent adhesiveness and heat resistance. The content of butyl acrylate in the monomer components constituting the acrylic polymer is more preferably 93% by mass or more.

[0066] Examples of copolymerizable monomers copolymerizable with the (meth)alkyl esters include carboxyl group-containing monomers such as (meth)acrylic acid, itaconic acid, maleic acid, fumaric acid, crotonic acid, and isocrotonic acid, or anhydrides thereof; sulfonic acid group-containing monomers such as sodium vinyl sulfonate; aromatic vinyl compounds such as styrene and substituted styrene; cyano group-containing monomers such as acrylonitrile; olefins such as ethylene, propylene, and butadiene; vinyl esters such as vinyl acetate; vinyl chloride; amide group-containing monomers such as acrylamide, methacrylamide, N-vinylpyrrolidone, and N,N-dimethyl(meth)acrylamide; hydroxyl group-containing monomers such as hydroxyalkyl (meth)acrylate and glycerin dimethacrylate; and amino group-containing monomers such as aminoethyl (meth)acrylate and (meth)acryloylmorpholine. Examples of the copolymerizable monomer include imide group-containing monomers such as cyclohexylmaleimide and isopropylmaleimide; epoxy group-containing monomers such as glycidyl (meth)acrylate and methylglycidyl (meth)acrylate; isocyanate group-containing monomers such as 2-methacryloyloxyethyl isocyanate; and polyfunctional copolymerizable monomers (polyfunctional monomers) such as triethylene glycol di(meth)acrylate, diethylene glycol di(meth)acrylate, ethylene glycol di(meth)acrylate, tetraethylene glycol di(meth)acrylate, neopentyl glycol di(meth)acrylate, 1,6-hexanediol di(meth)acrylate, trimethylolpropane tri(meth)acrylate, pentaerythritol tri(meth)acrylate, dipentaerythritol hexa(meth)acrylate, and divinylbenzene. The copolymerizable monomers can be used alone or in combination of two or more. As the copolymerizable monomer, a modifying monomer having a functional group such as a carboxyl group can be suitably used. Among them, acrylic polymers containing acrylic acid in the range of 0.5% to 4.0% by mass of the monomer components constituting the acrylic polymer are preferred because they have excellent adhesive properties and heat resistance. A more preferred content of acrylic acid in the monomer components constituting the acrylic polymer is in the range of 1.5% to 3.5% by mass.

[0067] The mass average molecular weight (Mw) of the acrylic polymer is preferably in the range of 400,000 to 1,200,000, and more preferably in the range of 500,000 to 1,000,000. When the mass average molecular weight of the acrylic polymer is in the above range, it is likely to exhibit sufficient adhesiveness and heat resistance even in a thin film. The mass average molecular weight is measured by GPC in terms of styrene.

[0068] The content of the acrylic polymer in the adhesive layer can be 20% by mass or more, preferably 30% by mass or more, preferably 50% by mass or more, more preferably 70% by mass or more, and even more preferably 80% by mass or more, of the total amount (100% by mass) of the adhesive layer.

[0069] The acrylic polymer can be prepared by a conventional polymerization method such as solution polymerization, emulsion polymerization, or ultraviolet irradiation polymerization.

[0070] The pressure-sensitive adhesive contains at least an acrylic polymer, and may contain additives such as a crosslinking agent, a tackifier, a softener, a plasticizer, a filler, an antioxidant, and a colorant, as needed.

[0071] The pressure-sensitive adhesive layer preferably contains a tackifier. By including a tackifier resin in the pressure-sensitive adhesive layer, the adhesive strength, tensile strength, and tensile break strength of the pressure-sensitive adhesive layer can be increased. The tackifier can be appropriately selected depending on the acrylic polymer used in the pressure-sensitive adhesive. Examples of the tackifier include rosin-based resins such as rosin and rosin ester compounds; terpene-based resins such as diterpene polymers and α-pinene-phenol copolymers; petroleum resins such as aliphatic (C5) and aromatic (C9) resins; and other styrene-based resins, phenol-based resins, and xylene resins. In particular, for pressure-sensitive adhesives using acrylic polymers whose main monomer component is n-butyl (meth)acrylate, it is preferable to use a mixture of a rosin-based resin and a styrene-based resin to achieve both adhesive strength and heat resistance in a thin film. Furthermore, to increase the initial adhesive strength of the pressure-sensitive adhesive layer, it is more preferable for the pressure-sensitive adhesive layer to contain a tackifier that is liquid at room temperature. Examples of tackifier resins that are liquid at room temperature include the above-mentioned liquid tackifier resins that are solid at room temperature, process oil, polyester plasticizers, and low-molecular-weight liquid rubbers such as polybutene. Terpene phenol resins are particularly preferred. Commercially available products include YP-90L manufactured by Yasuhara Chemical Co., Ltd.

[0072] The amount of tackifier is not particularly limited, but is preferably in the range of 10 to 70 parts by mass, more preferably 20 to 60 parts by mass, per 100 parts by mass of the acrylic copolymer. By setting the amount of tackifier in the above range, adhesive strength can be improved.

[0073] (Flame retardant) The pressure-sensitive adhesive layer preferably contains a flame retardant. The flame retardancy of the pressure-sensitive adhesive layer synergizes with the flame retardancy of the colored film alone, thereby increasing the flame retardancy of the colored pressure-sensitive adhesive tape alone. The flame retardant contained in the pressure-sensitive adhesive layer is not particularly limited, and specific examples of the flame retardant can be the same as those of the flame retardants contained in the resin film described above. Among these, it is preferable to contain at least a phosphorus-based compound, and among phosphorus-based compounds, ammonium polyphosphate is most preferred. The inclusion of ammonium polyphosphate forms a carbonized layer, which can suppress melting of the resin film during combustion, further improving the flame retardancy of the entire pressure-sensitive adhesive tape. In particular, when combined with a polycarbonate film, even if the flame retardancy of the film is at the VTM-2 level, the pressure-sensitive adhesive tape alone can achieve VTM-0.

[0074] The content of the flame retardant in the pressure-sensitive adhesive layer is preferably 65 parts by mass or more, more preferably 70 parts by mass or more, and even more preferably 80 parts by mass or more, relative to 100 parts by mass of the base polymer (acrylic polymer in the case of an acrylic pressure-sensitive adhesive). By setting the content of the flame retardant within the above range, the pressure-sensitive adhesive layer can ensure the desired flame retardancy. There is no particular upper limit for the content of the flame retardant from the viewpoint of obtaining flame retardancy, but if the content is excessively high, the flame retardant may be exposed on the surface of the pressure-sensitive adhesive layer, resulting in a decrease in adhesive strength. Therefore, the content is preferably 300 parts by mass or less, more preferably 200 parts by mass or less, and even more preferably 150 parts by mass or less. Note that, in this specification, the content standard (e.g., base polymer, pressure-sensitive adhesive, etc.) is based on the non-volatile components (solid content).

[0075] The gel fraction of the pressure-sensitive adhesive layer is not particularly limited, but is preferably in the range of 7% to 80% because sufficient adhesiveness and heat resistance are easily achieved even in a thin film, more preferably in the range of 15% to 60%, and even more preferably in the range of 18% to 55%. The gel fraction is determined by immersing the pressure-sensitive adhesive layer after aging in toluene, leaving it for 24 hours, measuring the mass of the remaining insoluble matter after drying, and expressing it as a percentage of the original mass.

[0076] Gel fraction (%) = [(mass of adhesive layer after immersion in toluene) / (mass of adhesive layer before immersion in toluene)] × 100

[0077] [Colored adhesive tape] The colored adhesive tape of the present invention may have a release liner on the surface of the adhesive layer to protect the adhesive layer. Any known release liner may be appropriately selected and used as the release liner. Resin films that have been subjected to a release treatment are preferred because they have excellent smoothness. Among these, polyester films that have excellent heat resistance and are subjected to a release treatment are preferred. The total thickness of the colored adhesive tape referred to in the present invention refers to the total thickness of the tape excluding the release liner.

[0078] The surface of the release liner is preferably provided with a release treatment layer to provide easy releasability. The release treatment layer can be formed using various release treatment agents used for release liners of double-sided pressure-sensitive adhesive tapes, and preferred examples of such release treatment agents include silicone-based, fluorine-based, and long-chain alkyl-based release treatment agents. The release treatment layer may also be formed on the above-mentioned resin film by lamination or coating.

[0079] The peel strength of the release liner may be adjusted as appropriate depending on the mode of use, etc., but it is preferable to set the peel strength from the adhesive layer in the range of 0.01 N / 20 mm to 2 N / 20 mm, preferably 0.05 N / 20 mm to 0.15 N / 20 mm, because this makes it easier to suppress deformation of the colored adhesive tape of the present invention when the release liner is peeled off. The peel strength can be measured by peeling the release liner or the adhesive layer backed with a 50 μm thick PET at a speed of 0.3 to 10 m / min in a 180° direction.

[0080] The colored pressure-sensitive adhesive tape of the present invention may have a configuration in which other functional layers are included.

[0081] The colored adhesive tape of the present invention has excellent designability, flame retardancy, and alcohol resistance due to the inclusion of the above-mentioned colored film, and can therefore be suitably used for protecting and joining components used in electronic devices that require flame retardancy, particularly electronic devices equipped with batteries, etc. In other words, the colored adhesive tape of the present invention can be used as a colored adhesive tape for protecting electronic circuit components. [Example]

[0082] The present invention will be explained in more detail below by way of examples. Note that the "parts" used to indicate the amounts of materials used in the production of the film and adhesive are "parts by mass." In the examples and comparative examples, the black matte film corresponds to the colored film, and the black matte adhesive tape corresponds to the colored adhesive tape.

[0083] <Creating black matte film> (Black Matte Film 1) To 100 parts of polycarbonate resin powder made from bisphenol A ("Iupilon (registered trademark) E-2000" manufactured by Mitsubishi Engineering-Plastics Corporation, viscosity-average molecular weight: 28,000), 1.6 parts of carbon black (manufactured by Mitsubishi Chemical Corporation, product name "#850" (average particle size: 17 nm, oil absorption: 77 ml / 100 g, BET specific surface area: 220 m / g)) and 4.8 parts of talc (manufactured by Matsumura Sangyo Co., Ltd., granular talc "R-10 (product name)" average particle size: 1.8 μm) were added and uniformly mixed, and the mixture was melted and kneaded at a cylinder temperature of 275°C to produce black polycarbonate resin pellets A.

[0084] The black polycarbonate resin pellets A were dried in a hot air dryer at 120°C for 6 hours, and then extruded using a T-die. The pellets were nipped between two embossed rolls (Ra = 3 μm) and cooled at 90°C to give them an uneven texture, resulting in a 100 μm thick black matte film 1.

[0085] (Black Matte Film 2) The black polycarbonate resin pellets A were dried in a hot air dryer at 120°C for 6 hours, then extruded using a T-die, and nipped with two embossed rolls (Ra = 1 μm) while cooling at 90°C to give them an uneven shape, to obtain a 100 μm thick black matte film 2.

[0086] (Black Matte Film 3) Black polycarbonate resin pellets B were produced by adding 1.6 parts of carbon black (manufactured by Mitsubishi Chemical Corporation, product name "#850" (average particle size: 17 nm, oil absorption: 77 ml / 100 g, BET specific surface area: 220 m / g)) and 3.5 parts of talc (manufactured by Matsumura Sangyo Co., Ltd., granular talc "R-10 (product name)" average particle size: 1.8 μm) to 100 parts of polycarbonate resin powder made from bisphenol A (manufactured by Mitsubishi Engineering Plastics Corporation, "Iupilon (registered trademark) E-2000", viscosity-average molecular weight: 28,000) and uniformly mixing the mixture. The mixture was then melted and kneaded at a cylinder temperature of 275°C.

[0087] The black polycarbonate resin pellets B were dried in a hot air dryer at 120°C for 6 hours, and then extruded using a T-die. The pellets were nipped between two embossed rolls (Ra = 3 μm) and cooled at 90°C to give them an uneven texture, resulting in a 50 μm thick black matte film 3.

[0088] (Black Matte Film 4) (Production of polyester polyurethane resin) 50 parts by mass of isophthalic acid, 50 parts by mass of neopentyl glycol, 80 parts by mass of toluene, and 40 parts by mass of methyl ethyl ketone were added to a four-neck flask equipped with a stirrer, a thermometer, a reflux condenser, and a nitrogen gas inlet tube, and the mixture was reacted at 80°C for 4 hours with stirring. Subsequently, 40 parts by mass of isophorone diisocyanate and 20 parts by mass of methyl ethyl ketone were mixed in, and the mixture was reacted at 100°C for approximately 1 hour, yielding a polyester polyurethane resin with a resin solids content of 50% and a mass average molecular weight of 40,000.

[0089] (Black ink manufacturing) A black ink was prepared by adding 100 parts by weight of polyester polyurethane resin (50% resin solids), 40 parts by weight of Degussa carbon black "Carbon Special 250P," 23 parts by weight of methyl ethyl ketone, 13 parts by weight of toluene, 6 parts by weight of ethyl acetate, 3 parts by weight of N-propyl acetate, and 3 parts by weight of isopropyl alcohol to a mixture wet dispersed in a sand mill for approximately 1 hour, to which 2 parts of DIC hardener "KR90" (biuret form of hexamethylene diisocyanate, 40% solids) and 300 parts of ethyl acetate were added. The carbon black content of the black ink solids was 44%.

[0090] (Matte ink manufacturing) A matte ink was prepared in the same manner as the black ink, except that Degussa's Carbon Special 250P was not used, and Fuji Silysia's Silica 440 (untreated silica: average particle size 3.5 μm as measured by the coal counter method) was used.

[0091] Black ink was gravure coated onto a polyester film "Lumirror S10" (thickness: 100 μm) manufactured by Toray Industries, Inc. to a dry thickness of 2.0 μm, and then dried. A matte ink layer was gravure coated on top of the black ink layer to a thickness of 1.0 μm, and then dried. The film was then aged at 40°C for one day to obtain black matte film 4.

[0092] (Black Matte Film 5) Black ink was gravure coated onto a flame-retardant polycarbonate film (UL94VTM-0) "Iupilon Film FE-2000N-7" (thickness: 100 μm) manufactured by Mitsubishi Gas Chemical Company, Inc., to a dry thickness of 2.0 μm, and then dried. A matte ink layer was gravure coated on top of the black ink layer to a thickness of 1.0 μm, dried, and aged at 40°C for 1 day to obtain black matte film 5.

[0093] (Black Matte Film 6) A black polyester film ("Lumirror X30" manufactured by Toray Industries, Inc., thickness: 100 μm) was used as the black matte film 6.

[0094] (Black Matte Film 7) A black polycarbonate film (manufactured by Sumitomo Bakelite Co., Ltd., "PHF860MAB", both sides matte, thickness: 50 μm) was used as black matte film 7.

[0095] (Black Matte Film 8) While the black matte film 6 was being transported at a speed of 5 m / min, one side of the film was sandblasted by shooting 20 kg / m2 of No. 7 silica sand as shot material, followed by rinsing with water for 3 minutes and drying at 80°C for 2 minutes to obtain black matte film 8.

[0096] Example 1 Black matte film 1 was used as Example 1.

[0097] Example 2 Black matte film 2 was used as Example 2.

[0098] Example 3 Black matte film 3 was used as Example 3.

[0099] (Comparative Example 1) Black Matte Film 4 was used as Comparative Example 1.

[0100] (Comparative Example 2) Black matte film 5 was used as Comparative Example 2.

[0101] (Comparative Example 3) Black matte film 6 was used as Comparative Example 3.

[0102] Comparative Example 4 Black matte film 7 was used as Comparative Example 4.

[0103] (Comparative Example 5) Black matte film 8 was used as Comparative Example 5.

[0104] [evaluation] (Arithmetic mean roughness Ra, ten-point mean roughness Rz) The obtained black matte film and black matte adhesive tape were subjected to surface measurements at three arbitrary points on the uneven surface using an Olympus OLS4100 in accordance with the provisions of JIS B0601:2013, and the average value of the three points obtained in the measurements was used.

[0105] (60° gloss value) The gloss values of the obtained black matte film and black matte adhesive tape were measured at 10 random locations on the textured surface of the black matte film using a glossmeter (MINOLTA Multi-Gloss 268, manufactured by KONICA MINOLTA) at a set angle of 60° in accordance with JIS Z 8741, and the average value was calculated. The presence or absence of an adhesive layer did not affect the gloss value, and the measurement results for each black matte film and black matte adhesive tape were the same. The results are shown in Tables 1 and 2. A gloss value of 4 or less was considered to have a high matte finish.

[0106] (CIE Lab color system hue (L * value, a * value, b * Measurement of (value) The obtained black matte film and black matte adhesive tape were measured from the uneven surface side of the black matte film using a spectrophotometer (CM-5, manufactured by Konica Minolta, Inc.) in accordance with the measurement standard JIS Z 8722, where the C spectrum is 10°. The presence or absence of the adhesive layer was determined by the hue (L * value, a * value, b * The measured values for the black matte film and the black matte adhesive tape were the same.

[0107] (Flame retardant 1) The resulting black matte film and black matte adhesive tape were subjected to a test (ISO9773 1998) based on the thin material vertical flame test method of UL94, a flame retardancy test standard for plastic materials, to determine the VTM rank. The sample size of the sheet used for evaluation was 50mm x 200mm, and if there was an adhesive layer, the release liner was peeled off to expose the adhesive layer. The VTM rank determination criteria are as follows: -Judgment criteria- VTM-0: The sample burns for 10 seconds or less, and the absorbent cotton is not ignited by burning or falling objects, and no combustion is observed up to the marked line (125 mm from the bottom end of the sample). VTM-1: The sample burns for 30 seconds or less, and the absorbent cotton is not ignited by burning or falling objects, and no burning is observed up to the marked line. VTM-2: The sample burns for less than 30 seconds and does not burn to the marked line.

[0108] In the table, those that conformed to VTM-0 are marked "VTM-0", those that did not conform to VTM-0 but conformed to VTM-1 are marked "VTM-1", those that did not conform to VTM-0 or VTM-1 but conformed to VTM-2 are marked "VTM-2", and those that did not conform to VTM-0, VTM-1 or VTM-2 are marked "Failed".

[0109] (adhesive strength) The obtained black matte adhesive tape was cut into a width of 25 mm, and the peel adhesive strength (peel angle: 180°, tensile speed: 300 mm / min, 23°C × 50% RH, adherend: stainless steel plate, application time: 1 hour) was measured using a Tensilon tensile tester in accordance with JIS Z0237.

[0110] (alcohol resistant) The same spot on the textured surface of the black matte film was rubbed 100 times with a cloth soaked in ethanol. The alcohol resistance was evaluated based on the change in gloss value before and after the test. -Judgment criteria- ○: Change is less than 1. ×: The change is 1 or more.

[0111] The evaluation results are shown in the table below.

[0112] [Table 1]

[0113] [Table 2]

[0114] The black matte films obtained in the Examples achieved a gloss value of 4 or less, providing excellent design due to the matte finish, and also achieved flame retardancy of VTM-2 or higher and excellent alcohol resistance on the surface (matte side).On the other hand, the black matte films obtained in the Comparative Examples were unable to achieve both design, alcohol resistance on the surface (matte side), and flame retardancy.

[0115] In more detail, black matte film 4 of Comparative Example 1, in which a black ink layer and a matte layer were formed as separate layers on a polyester film, and black matte film 5 of Comparative Example 2, in which a black ink layer and a matte layer were formed as separate layers on a polycarbonate film, achieved a gloss value of 4 or less, but were unable to achieve flame retardancy or surface (matte side) alcohol resistance of VTM-2 or higher.

[0116] Furthermore, the commercially available black matte film 6 of Comparative Example 3 and black matte film 7 of Comparative Example 4 did not achieve a gloss value of 4 or less, and did not achieve a high matte tone. Furthermore, black matte film 8 of Comparative Example 5, which was obtained by sandblasting black matte film 6, had a lower gloss value than black matte film 6 but did not achieve a gloss value of 4 or less, and furthermore, the alcohol resistance of the surface (matte side) was inferior.

[0117] <Manufacturing of black matte adhesive tape> (Production of adhesive A) A reaction vessel equipped with a condenser, stirrer, thermometer, and dropping funnel was charged with 97.98 parts n-butyl acrylate, 2 parts acrylic acid, 0.02 parts 4-hydroxybutyl acrylate, and 0.2 parts azobisisobutyronitrile as a polymerization initiator. The mixture was solution-polymerized in ethyl acetate at 80°C for 8 hours to yield an acrylic polymer with a mass-average molecular weight of 900,000. To 100 parts of the acrylic polymer, 5 parts of polymerized rosin ester (trade name "D-135" manufactured by Arakawa Chemical Industries, Ltd.), 20 parts of disproportionated rosin ester (trade name "KE-100" manufactured by Arakawa Chemical Industries, Ltd.), and 25 parts of petroleum resin (trade name "FTR6100") were added, followed by the addition of ethyl acetate to prepare a 40% solids adhesive solution. 0.8 parts of an isocyanate-based crosslinker (trade name "NC40" manufactured by DIC Corporation) was then added and stirred until homogeneous, yielding Adhesive A. The gel fraction of adhesive A is 20%, and the storage modulus at 25°C is 9×10 4 It was Pa.

[0118] (Production of flame-retardant adhesive B) In a reaction vessel equipped with a condenser, a stirrer, a thermometer, and a dropping funnel, 48 parts of 2-ethylhexyl acrylate, 48 parts of n-butyl acrylate, 3.5 parts of acrylic acid, 0.5 parts of 2-hydroxyethyl acrylate, and 0.2 parts of 2,2'-azobisisobutyronitrile as a polymerization initiator were dissolved in 100 parts of ethyl acetate, and after replacing the atmosphere with nitrogen, polymerization was carried out at 80°C for 8 hours, yielding an acrylic acid ester copolymer solution with a solids content of 50% and a weight-average molecular weight of 450,000.

[0119] To 100 parts by weight of the solid content of the obtained acrylic ester copolymer, 80 parts by weight of ammonium polyphosphate (Terrage C60 manufactured by Chisso Corporation), 40 parts by weight of aluminum hydroxide (H-32 manufactured by Showa Denko K.K.), 18 parts by weight of polyhydric alcohol (Dipentalit 300 manufactured by Koei Chemical Industry Co., Ltd.), 3 parts by weight of an epoxy-based crosslinking agent (E-05X manufactured by Soken Chemical & Engineering Co., Ltd., solid content 0.5%), and toluene were added and stirred thoroughly until homogeneous, to obtain flame-retardant adhesive B.

[0120] Example 4 The adhesive A was applied to a release film (Nippa Corporation's "PET25xJ0L") using a roll coater to a dry thickness of 50 μm, dried at 100°C for 1 minute, and then bonded to black matte film 1 and aged at 40°C for 2 days to obtain a black matte adhesive tape.

[0121] Example 5 The above flame-retardant adhesive B was applied to a release film (Nippa Corporation's "PET25xJ0L") using a roll coater to a dry thickness of 50 μm, and dried at 100°C for 1 minute.This was then bonded to black matte film 1 and further aged at 40°C for 2 days to obtain a black matte adhesive tape.

[0122] The obtained black matte adhesive tape was subjected to the evaluations described above. The results are shown in Table 3.

[0123] (Flame retardant 2) The resulting black matte adhesive tape was laminated to aluminum foil (50 μm thick) to form a laminate. The laminate was then subjected to a test (ISO 9773 1998) based on the thin material vertical flame test method of UL 94, a flame retardancy test standard for plastic materials, to determine the VTM rank of the black matte adhesive tape in the laminate. The sample sizes of the laminate and the black matte adhesive tape used for evaluation were both 50 mm × 200 mm. The release liner on the adhesive layer was peeled off, and the laminate was then laminated with aluminum foil (50 μm thick). The VTM rank rating criteria were the same as those used for the evaluation of "Flame Retardance 1" above. The results are shown in Table 3.

[0124] [Table 3]

[0125] The black matte adhesive tapes of Examples 4 and 5 were able to exhibit flame retardancy of VTM-2 or higher when laminated to an adherend (aluminum foil). The black matte adhesive tape of Example 5 in particular exhibited extremely high flame retardancy even when used alone, and also achieved extremely high flame retardancy when laminated to an adherend (aluminum foil). The black matte adhesive tape of Example 4 had poor flame retardancy when used alone because the adhesive layer burned. However, by laminating the tape to an adherend (aluminum foil), the adhesive layer was sandwiched between the adherend and the black matte film, suppressing combustion of the adhesive layer. It is presumed that this allowed the tape to achieve flame retardancy of VTM-0 in the flame retardancy rating 2. [Explanation of symbols]

[0126] 10...Colored film 11...Adhesive layer 20...Colored adhesive tape 1...Resin film

Claims

1. A colored film having a resin film containing a colorant, the resin film has an uneven shape on at least one surface, The 60° gloss value is 4 or less, A colored film that exhibits VTM-2 or higher in flammability tests in accordance with the UL94VTM method (ISO9773 1998).

2. A colored film having a resin film containing a colorant, the resin film has an uneven shape on one surface, the arithmetic mean roughness Ra of the surface of the resin film having the irregular shape is 0.9 μm or more and 6.0 μm or less; A colored film that exhibits VTM-2 or higher in flammability tests in accordance with the UL94VTM method (ISO9773 1998).

3. 3. The colored film according to claim 1, wherein the colored film consists of a single layer of the resin film.

4. The colored film according to claim 1 or 2, wherein the resin film has the uneven shape formed on the one surface thereof.

5. 3. The colored film according to claim 1, wherein the resin film is a polycarbonate film.

6. 3. The colored film according to claim 1, wherein L* is 20 to 29, a* is -1 to 1, and b* is -2 to 0 in the CIE Lab color system.

7. 2. The colored film according to claim 1, wherein the ten-point average roughness Rz of the surface of the resin film having the irregular shape is 7.0 μm or more and 40.0 μm or less.

8. 3. The colored film according to claim 1, wherein the content of the colorant in the resin film is 0.5% by mass or more and 5% by mass or less.

9. 9. A colored adhesive tape comprising the colored film according to claim 1, and an adhesive layer on a surface of the colored film opposite to the surface of the resin film having the irregularities.

10. The colored adhesive tape according to claim 9 , wherein the adhesive layer contains a flame retardant.

11. The colored adhesive tape according to claim 10, which exhibits VTM-2 or higher in a flammability test in accordance with the UL94 VTM method (ISO9773 1998).

12. A method for producing a colored film according to any one of claims 1 to 8, A method for producing a colored film, comprising a step of transferring the surface shape of a shaping plate onto one side of a resin film containing a colorant to form a concave-convex shape.

13. The method for producing a colored film according to claim 12, wherein the surface shape of the shaped plate satisfies at least one of the following (1) or (2): (1) The arithmetic mean roughness Ra is 0.6 μm or more and 5.0 μm or less. (2) The ten-point average roughness Rz is 4.0 μm or more and 35.0 μm or less.

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