Marking film and method for manufacturing the marking film

Abstract

To provide a marking film which can suppress deterioration in matte feeling even when stretched by molding.SOLUTION: A marking film has an adhesive layer, a coloring layer and a transparent layer, wherein the transparent layer contains transparent particles, and an urethane-based resin, a fluorine-containing resin or an acrylic resin, and has a glossiness of 1-50.SELECTED DRAWING: Figure 1

Description

Technical Field

[0001] The present invention relates to a marking film.

Background Art

[0002] For example, surface decoration methods for unevenly shaped products have attracted attention in recent years for the purpose of enhancing the added value of the molded products and imparting a high-class feeling. As such a surface decoration method, since the surface of the molded product often has a complex three-dimensional shape, after applying a pattern on the molded product, a method of protecting and coating this pattern layer can be mentioned. However, such a method requires man-hours and time for the working process, resulting in an increase in cost.

[0003] Therefore, as a method that requires fewer working processes and can decorate the surface at low cost, a method of directly adhering a marking film to an unevenly shaped product is desired. As such a method, for example, Patent Document 1 discloses a method for manufacturing a laminated molded product having a lamination step of laminating a marking film on the surface of an unevenly shaped product by vacuum molding (TOM molding).

[0004] On the other hand, for the purpose of imparting a high-class feeling, it is known to apply a matte finish with low gloss to the marking film (Patent Document 2).

Prior Art Documents

Patent Documents

[0005]

Patent Document 1

Patent Document 2

Summary of the Invention

Problems to be Solved by the Invention

[0006] When the inventors directly adhere a matte marking film with low gloss to a concavo-convex molded product, they found that when the marking film is stretched, the unevenness difference on the surface decreases, and the interval between adjacent convex parts widens, resulting in a decrease in the matte feeling of the marking film.

[0007] The present invention was invented to solve the above problems, and an object thereof is to provide a marking film capable of suppressing a decrease in matte feeling even when stretched by molding.

Means for Solving the Problems

[0008] The marking film according to the present invention that achieves the above object has an adhesive layer, a coloring layer, and a transparent layer adjacent to the coloring layer. The transparent layer includes transparent particles and at least one selected from the group consisting of a urethane resin, a fluorine-containing resin, and an acrylic resin, and has a glossiness of 1 to 50. The coloring layer is a concealing layer. The transparent layer has an uneven shape, the thickness of the transparent layer is 30 to 50 μm, and the volume average particle diameter of the transparent particles is 1 to 30 μm.

Effects of the Invention

[0009] According to the above-described marking film, when the marking film is stretched by molding, the transparent particles suppress a decrease in the unevenness difference on the surface and cause new convex parts to appear in the concave parts between adjacent convex parts with widened intervals. Therefore, even when stretched by molding, a decrease in matte feeling can be suppressed.

Brief Description of the Drawings

[0010]

Figure 1

Figure 2

Figure 3

Figure 4

Best Mode for Carrying Out the Invention

[0011] Hereinafter, embodiments of the present invention will be described with reference to the attached drawings. In the description of the drawings, the same elements are denoted by the same reference numerals, and redundant descriptions are omitted. Also, the dimensional ratios in the drawings are exaggerated for the convenience of explanation and may be different from the actual ratios.

[0012] In this specification, "X to Y" indicating a range means "X or more and Y or less". Also, unless otherwise specified, operations and measurements of physical properties are performed under the conditions of room temperature (20 to 25°C) / relative humidity 45 to 55%.

[0013] Hereinafter, with reference to FIGS. 1 and 2, the marking film 1 according to this embodiment will be described. FIG. 1 is a schematic cross-sectional view showing the state of the marking film 1 according to this embodiment before stretching. FIG. 2 is a schematic cross-sectional view showing the state of the marking film 1 according to this embodiment after stretching.

[0014] The marking film 1 according to this embodiment has, in order from the top as shown in FIG. 1, a transparent layer 10, a colored layer 20, an adhesive layer 30, and a release liner 40.

[0015] The elongation at break of the marking film 1 is preferably 250 to 600%. When the elongation at break of the film is within such a range, the working efficiency when attaching the film to the uneven molded product is improved. The elongation at break can be obtained by measuring the tensile strength at a tensile speed of 200 mm / min in accordance with JIS K 7127:1999 after gripping the sample with a tensile test apparatus.

[0016] The glossiness of the marking film 1 is from 1 to 50, more preferably from 3 to 30. When the glossiness of the marking film 1 is within such a range, an appropriate matte feeling is imparted. Here, the glossiness refers to the 60-degree specular glossiness. The 60° specular glossiness is measured using a gloss meter "VG7000" manufactured by Nippon Denshoku Industries Co., Ltd. in accordance with JIS Z8741:1997. The 60° specular glossiness can be controlled by the content of transparent particles in the transparent layer, the particle diameter of the transparent particles in the transparent layer, the surface roughness of the transparent layer, etc.

[0017] The difference between the glossiness of the marking film 1 after 200% stretching and the glossiness before stretching is preferably within 20 (the glossiness after 200% stretching is within ±20 with respect to the glossiness before stretching), more preferably within 10, and even more preferably 4 or less. When the difference is within such a range, the matte feeling before and after stretching becomes the same level, and the influence on visibility is reduced.

[0018] <Transparent layer 10> The transparent layer 10 is a main component in the marking film 1 and can be composed of various materials according to the application for which the marking film 1 is used. Considering the case where it is attached to the surface of the uneven molded product by a vacuum forming method or the like, the material constituting the transparent layer 10 needs to be stretchable to the extent that it can follow the three-dimensional shape of the uneven molded product.

[0019] The transparent layer 10 contains a urethane-based resin, a fluorine-containing resin, or an acrylic-based resin. By including a urethane-based resin or an acrylic-based resin in the transparent layer 10 in this way, the scratch resistance and weather resistance of the transparent layer 10 are improved, the transparency of the transparent layer 10 is improved, and the visibility of the coloring layer 20 is improved. Note that the transparent layer 10 may contain a known pigment.

[0020] As the urethane resin, a thermoplastic polyurethane resin is preferred. The thermoplastic polyurethane resin is obtained by reacting at least a polyisocyanate, a high molecular weight polyol, and a chain extender. Specifically, it is preferably obtained by reacting a chain extender with a terminal isocyanate urethane prepolymer obtained by reacting a polyisocyanate and a high molecular weight polyol. Examples of the polyisocyanate include aromatic polyisocyanates, aliphatic polyisocyanates, alicyclic polyisocyanates, etc. The polyisocyanate may be a trimethylolpropane adduct type modified product of the above polyisocyanate, a biuret type modified product reacted with water, or an isocyanurate type modified product containing an isocyanurate ring. The high molecular weight polyol is an organic compound having two or more hydroxyl groups and a number average molecular weight of 400 or more, preferably 1000 to 3000. Examples thereof include macropolyols such as polyether polyol, polyester polyol, polycarbonate polyol, acrylic polyol, epoxy polyol, natural oil polyol, silicone polyol, fluorine polyol, polyolefin polyol, and polyurethane polyol. The high molecular weight polyol may be used alone or in combination of two or more. The method for preparing the terminal isocyanate urethane prepolymer is not particularly limited. For example, a method of charging a polyisocyanate, a high molecular weight polyol, a urethanization catalyst added as necessary, and a solvent used as necessary into a reactor and reacting them can be mentioned.Examples of the chain extender include low molecular weight polyhydric alcohols having a number average molecular weight of less than 400 such as ethylene glycol, diethylene glycol, 1,4-butanediol, 1,6-hexanediol, trimethylolpropane, pentaerythritol, and sorbitol; low molecular weight polyamine compounds such as ethylenediamine, 1,3-propanediamine, hexamethylenediamine, diaminocyclohexylmethane, piperazine, 2-methylpiperazine, isophoronediamine, diethylenetriamine, and triethylenetetramine; diamines having a hydroxyl group in the molecule such as 2-hydroxyethylethylenediamine, 2-hydroxyethylpropylenediamine, di-2-hydroxyethylethylenediamine, di-2-hydroxyethylpropylenediamine, 2-hydroxypropyl ethylenediamine, and di-2-hydroxypropyl ethylenediamine; alkylene dihydrazines such as methylene dihydrazine, ethylene dihydrazine, and propylene dihydrazine; saturated or unsaturated dihydrazines such as adipic acid dihydrazide, oxalic acid dihydrazide, malonic acid dihydrazide, succinic acid dihydrazide, phthalic acid dihydrazide, and itaconic acid dihydrazide; and dimer diamine obtained by converting the carboxyl group of dimer acid into an amino group. Further, these chain extenders can be used as chain terminators by using them in excess with respect to the isocyanate groups in the prepolymer.

[0021] Examples of the fluorine-containing resin include polyvinylidene fluoride, ethylene-tetrafluoroethylene copolymer, ethylene-chlorotrifluoroethylene copolymer, tetrafluoroethylene-perfluoroalkoxyethylene copolymer, tetrafluoroethylene-hexafluoropropylene copolymer, and polychlorotrifluoroethylene. Among them, as the fluorine-containing resin, ethylene-tetrafluoroethylene copolymer, ethylene-chlorotrifluoroethylene copolymer, tetrafluoroethylene-perfluoroalkoxyethylene copolymer, tetrafluoroethylene-hexafluoropropylene copolymer, and polychlorotrifluoroethylene are preferable.

[0022] An acrylic resin refers to a resin produced by polymerization using (meth)acrylic monomer as the main monomer component. Here, the main component means 50% by mass or more (upper limit 100% by mass), preferably 80% by mass or more, of the monomer component. As the (meth)acrylic monomer, for example, acrylic esters such as methyl acrylate, ethyl acrylate, n-butyl acrylate, isobutyl acrylate, hexyl acrylate, cyclohexyl acrylate, lauryl acrylate, stearyl acrylate; acrylic acid; methacrylic esters such as methyl methacrylate, ethyl methacrylate, n-butyl methacrylate, isobutyl methacrylate, hexyl methacrylate, cyclohexyl methacrylate, lauryl methacrylate, stearyl methacrylate; methacrylic acid; etc. can be used. This (meth)acrylic monomer can also be used as a mixture of two or more kinds.

[0023] The acrylic resin may contain, as monomers during polymerization, other monomers copolymerizable with the (meth)acrylic monomer. For example, carboxyl group-containing monomers such as itaconic acid, maleic acid, fumaric acid, crotonic acid, isocrotonic acid or their anhydrides; sulfonic acid group-containing monomers such as sodium vinyl sulfonate; aromatic vinyl compounds such as styrene, substituted styrene; cyano group-containing monomers such as acrylonitrile; olefins such as ethylene, propylene, butadiene; vinyl esters such as vinyl acetate; vinyl chloride; amide group-containing monomers such as acrylamide, methacrylamide, N-vinylpyrrolidone, N,N-dimethylacrylamide, etc. can be mentioned.

[0024] Also, a crosslinking agent may be used in combination with a urethane resin, a silicon-containing fluorine resin or an acrylic resin. Examples of the crosslinking agent include isocyanate-based crosslinking agents, epoxy-based crosslinking agents, metal chelate-based crosslinking agents, etc.

[0025] In addition, the materials contained in addition to the urethane resin, fluorine-containing resin, or acrylic resin are not particularly limited. For example, polyolefins such as polyethylene, polypropylene, polybutene, and polybutadiene, vinyl chloride resin, polyesters such as polyethylene terephthalate (PET), polybutylene terephthalate, and polyethylene naphthalate can be mentioned. Among these, considering stretchability (three-dimensional shape followability), transparency, design, durability, and cost, polyethylene, unstretched polypropylene, acrylic resin, and vinyl chloride resin are preferred. The above materials may be used alone or in the form of a mixture of two or more. Further, the transparent layer 10 may be composed of a single resin layer or may be formed by laminating different types of resin layers.

[0026] The thickness of the transparent layer 10 is not particularly limited, but considering stretchability (three-dimensional shape followability), breaking strength, scratch resistance, etc., it is preferably 5 to 200 μm, more preferably 10 to 150 μm, and even more preferably 30 to 50 μm. With such a thickness, molding can be easily performed.

[0027] Since the transparent layer 10 can function to protect the colored layer 20, it is necessary for the transparent layer 10 to have high transparency from the viewpoint of ensuring visibility. Specifically, the total light transmittance of the transparent layer 10 is preferably 70% or more (upper limit 100%), and more preferably 80% or more.

[0028] In order to prevent contamination of the transparent layer 10, a fluororesin layer can be laminated. Examples of the method of laminating the fluororesin layer include a method of applying a paint containing a fluororesin on the transparent layer, a method of melt coextruding the transparent layer and the fluororesin layer, and a method of bonding a fluororesin film via an adhesive layer on the transparent layer. From the viewpoint of suppressing a decrease in the matte feeling, the thickness of the fluororesin layer is preferably 10 μm or less, and more preferably 1 to 8 μm.

[0029] Examples of the fluororesin include polyvinylidene fluoride, ethylene-tetrafluoroethylene copolymer, ethylene-chlorotrifluoroethylene copolymer, tetrafluoroethylene-perfluoroalkoxyethylene copolymer, tetrafluoroethylene-hexafluoropropylene copolymer, polychlorotrifluoroethylene, silicon-containing fluororesin, and the like. As the silicon-containing fluororesin, the silicon-containing fluororesin described in JP-A-2001-163927, JP-A-2001-206918, JP-A-2004-115792, etc. can be used.

[0030] As shown in FIG. 1, the transparent layer 10 contains transparent particles 11. The transparent particles 11 are preferably spherical. Here, the spherical shape does not mean only a perfect sphere, and may be an ellipse, a substantially spherical shape, or a shape having fine holes or irregularities on the surface. If the ratio of the minor axis to the major axis is 1:1 to 1:2, it is preferably spherical. Since aggregation is suppressed and the effects of the present invention are more likely to be exhibited, the transparent particles are more preferably perfect spheres. The material constituting the transparent particles 11 is not particularly limited, and examples thereof include synthetic resins such as crosslinked (meth)acrylic resins, crosslinked styrene resins, polyurethane resins, polyester resins, silicone resins, fluororesins, and copolymers thereof; and inorganic substances such as silica, calcium carbonate, and barium sulfate. Among them, since the difference in refractive index from the urethane resin or the acrylic resin is small, transparency is easily ensured, and the effects of the present invention are easily obtained, it is preferable to use crosslinked (meth)acrylic resin particles as the transparent particles, and it is more preferable to use crosslinked methyl methacrylate (PMMA) particles. These crosslinked (meth)acrylic acid resin particles are made of, for example, (meth)acrylic acid esters such as methyl methacrylate and n-butyl methacrylate as raw materials. The crosslinking agent is not particularly limited, and general crosslinking agents such as epoxy-based crosslinking agents and isocyanate-based crosslinking agents can be used. The refractive index of the transparent particles is preferably 2.0 or less, and more preferably 1.2 to 1.6.

[0031] The hardness of the transparent particles 11 is higher than the hardness of the transparent layer 10.

[0032] The volume average particle diameter of the transparent particles 11 is not particularly limited. For example, when the thickness of the transparent layer 10 is 30 to 50 μm, the volume average particle diameter of the transparent particles 11 is preferably 1 to 30 μm, more preferably 1 to 15 μm, still more preferably 5 to 12 μm, and particularly preferably more than 7.5 μm and 10 μm or less.

[0033] Here, if the volume average particle diameter is less than 1 μm, the effects described below will not be preferably exhibited. Further, when the volume average particle diameter is larger than 30 μm, the amount of resin around the transparent particles relatively decreases, so there is a possibility that the transparent layer may be broken when the marking film is stretched, and there is a risk that it cannot be preferably stretched.

[0034] Note that the transparent particles 11 may include particles having the same volume average particle diameter in the transparent layer 10, or particles having different volume average particle diameters may be mixed and included in the transparent layer 10.

[0035] The addition amount of the transparent particles 11 is preferably 5 to 35% by mass of the transparent layer 10, and more preferably 10 to 30% by mass. For example, when it is less than 5% by mass, the effects described below will not be preferably exhibited. Further, when it is more than 35% by mass, the amount of resin around the transparent particles relatively decreases, so there is a possibility that the transparent layer may be broken when the marking film is stretched, and there is a risk that it cannot be preferably stretched.

[0036] The ten-point average surface roughness (Rz JIS ) on the surface layer side (the side opposite to the adhesive layer) of the transparent layer 10 is 0.1 to 30 μm. By Rz JIS being above the above lower limit, an appropriate matte feeling can be imparted, and by being below the above upper limit, transparency is easily ensured. The ten-point average surface roughness (Rz JIS ) is defined by JIS B0601:2001.

[0037] The method for forming the transparent layer 10 is not particularly limited. For example, after preparing a dispersion liquid (hereinafter referred to as the dispersion liquid for forming the transparent layer) in which a resin, transparent particles, and other optional components are dispersed in a solvent, this is formed by a solvent casting method in which it is cast onto a process paper or a process film (hereinafter also simply referred to as a process paper or the like) so as to have a predetermined dry thickness. Alternatively, the transparent layer may be formed by applying the dispersion liquid for forming the transparent layer onto the colored layer using the solvent casting method.

[0038] Examples of the material of the process film include synthetic resin films such as polyethylene terephthalate, polyethylene naphthalate, polyimide, and polypropylene. The process film may be in a form having a release layer such as an alkyd resin or silicone on these synthetic resin films. In this case, the transparent layer 10 is formed on the release layer forming surface. Examples of the process paper include high-quality paper, medium-quality paper, glassine paper, art paper, coated paper, and cast-coated paper. The thickness of the process paper or the like is preferably 5 to 200 μm, more preferably 15 to 100 μm. The process paper or the like may have a concavo-convex shape on its surface. By casting the dispersion liquid for forming the transparent layer onto the process paper or the like having such a concavo-convex shape, the concavo-convex shape of the process paper or the like is transferred to the transparent layer. Therefore, the transparent layer has a concavo-convex shape, and for example, it is easy to control the 10-point average surface roughness (Rz) of the surface of the transparent layer, and it is easy to obtain a matte feeling. The process paper or the like having concavo-convexities can be obtained by a conventionally known method.

[0039] In this way, the resin contained in the transparent resin layer can form the transparent layer by the solvent casting method. By using the solvent casting method, it is easy to control the physical properties by adding a crosslinking agent, and when directly coating the colored layer, the adhesion to the colored layer can be improved.

[0040] <Colored layer 20> The colored layer 20 is a concealing layer that prevents the base of the concavo-convex molded article from being seen through the transparent layer 10. Therefore, it is preferable that the concealment rate of the colored layer 20 is high. If the "concealment property" is defined more quantitatively, the concealment rate of the colored layer 20 according to the present invention is 70% or more. The "concealment rate" is an index indicating the ability to shield the color of the base, and is defined by JIS K5600-4-1:1999. After attaching the marking film 1 to the white part and the black part of the concealment rate test paper, the respective tristimulus values YW and YB are measured and calculated as the percentage of the ratio YB / YW of the concealment rate. This concealment rate is preferably 75% or more, and more preferably 78% or more.

[0041] The colored layer 20 can be, for example, a layer containing a black pigment such as carbon black. By having such a configuration, in the marking film 1 of the present embodiment, the colored layer 20 exhibits black.

[0042] Note that the colored layer 20 may be a luminescent layer. The luminescent layer is a layer having luminescence (metallic feeling). There is no particular limitation on the specific configuration of the luminescent layer, and conventionally known knowledge can be appropriately referred to. As an example, the luminescent layer may be a metal thin film layer formed by a dry film forming method such as vapor deposition or sputtering, or may be a luminescent pigment-containing layer containing a luminescent pigment and a binder. When the luminescent layer is formed by vapor deposition or sputtering, vapor deposition or sputtering is performed on the transparent layer 10 including the transparent particles 11. When the luminescent layer is a metal thin film layer, examples of the metal constituting the metal thin film layer include chromium, indium, tin, aluminum, and the like. When the luminescent layer is a luminescent pigment-containing layer, there is no particular limitation on the luminescent pigment contained in the luminescent pigment-containing layer, and conventionally known knowledge can be appropriately referred to. The luminescent pigment is, for example, one or more selected from the group consisting of an aluminum material, a pearl pigment, and a glass material. Specific examples of the aluminum material include aluminum powder, aluminum paste, and aluminum flakes. Aluminum powder is a metallic pigment that does not contain a solvent component, and also includes a material of a type in which aluminum particles are coated with a resin such as an acrylic resin. Further, aluminum paste is a material in which scaly fine particles of aluminum are surface-treated and made into a paste form with an organic solvent or the like. Furthermore, as an example of aluminum flakes, there is also a material of a type in which an aluminum vapor deposition film is pigmented. Further, as an example of the pearl pigment, there is a white pearl obtained by pulverizing mica into fine powder and performing surface treatment. Further, as an example of the glass material, there is a material of a luminescent pigment type in which scaly glass flakes or the flakes are further coated with a metal or a metal oxide.

[0043] Note that when the colored layer is a luminescent layer, a colored transparent layer may be provided above the luminescent layer. At this time, it is preferable that an adhesive layer is provided between the transparent layer 10 and the colored transparent layer. In the case of this configuration, the colored layer is formed by performing vapor deposition or sputtering on the colored transparent layer, and the transparent layer 10 including the transparent particles 11 is laminated on the colored layer via the adhesive layer.

[0044] The colored transparent layer contains, for example, a colorant and a binder as forming materials.

[0045] As the colorant, known pigments can be used. The color of the pigment is not particularly limited, but for example, red or blue.

[0046] Examples of the binder include vinyl chloride resin, acrylic resin, polyester resin, alkyd resin, epoxy resin, polyurethane resin, acrylic urethane resin, etc. These binders can also be used in combination with crosslinking agents such as amino resin, methylolated melamine resin, alkyl etherified melamine resin, urea resin, polyisocyanate compound, etc.

[0047] In this way, by disposing the colored transparent layer on the upper surface of the bright layer, the design property is improved.

[0048] If the preferred form of "black" is defined more quantitatively, in the marking film 1 according to the present invention, the colored layer 20 has a reflection density of 0.5 or more. "Reflection density" is a type of optical density and is defined as "-log10(reflectance)" using the reflectance (= amount of reflected light from the reflecting surface / amount of incident light on the reflecting surface). For example, when the reflectance is 10%, the reflection density is calculated as (-log10(0.1)) = 1, and when the reflectance is 1%, the reflection density is calculated as (-log10(0.01)) = 2. Conversely, the reflectance when the reflection density is 0.5 or more is (1 / 10)1 / 2 (≈31.6%) or less. This reflection density is preferably 0.8 or more, more preferably 1.0 or more, still more preferably 1.3 or more, particularly preferably 1.7 or more, and most preferably 2.0 or more.

[0049] Incidentally, the colored layer 20 may be a printed layer formed by screen printing using an ink containing a pigment such as carbon black. However, the means for forming the colored layer 20 is not limited thereto, and for example, a layer formed by offset printing, flexographic printing, gravure printing, spray coating, bar coating, or the like may also be used. Further, the colored layer may be formed by a calendar method, an extrusion method, a solution casting method, or the like.

[0050] In the present embodiment, as a means for making the colored layer 20 black and functioning as a concealing layer, carbon black, which is carbon particles, is added to the colored layer 20. As carbon black, various types such as oil furnace black, channel black, lamp black, thermal black, and acetylene black are known. In the present embodiment, any of them can be used. The colored layer is not limited to black. Further, as the colorant contained in the colored layer, in addition to the above carbon black, graphite (black lead), copper oxide, manganese dioxide, aniline black, perylene black, titanium black, cyanine black, activated carbon, ferrite (non-magnetic ferrite, magnetic ferrite, etc.), magnetite, chromium oxide, iron oxide, molybdenum disulfide, chromium complex, composite oxide-based black pigment, anthraquinone-based organic black pigment, and the like can be mentioned.

[0051] Also, there is no particular limitation on the value of the average particle diameter of the carbon particles used, and any form that can achieve the above-described concealment rate (preferably, the concealment rate and the reflection density) can be appropriately adopted. As an example, the average particle diameter of the carbon particles is preferably 10 to 100 nm, more preferably 20 to 80 nm, and particularly preferably 25 to 70 nm. The value of the average particle diameter of the carbon particles can be obtained, for example, by randomly selecting several to several tens of carbon particles from a photograph taken by an electron microscope and calculating the arithmetic mean value from the particle diameters (the maximum length connecting any two points on the contour line) of the selected individual carbon particles.

[0052] The content of the black pigment contained in the coloring layer 20 is not particularly limited and can be appropriately set in an amount capable of achieving a desired hiding power. As an example, the content of the black pigment in the coloring layer 20 is preferably 1 to 30 parts by mass, more preferably 5 to 20 parts by mass, and still more preferably 10 to 15 parts by mass with respect to 100 parts by mass of the solid content constituting the coloring layer 20.

[0053] The coloring layer 20 preferably contains a binder. Examples of usable binders include vinyl chloride resins, acrylic resins, polyester resins, alkyd resins, epoxy resins, polyurethane resins, acrylic urethane resins, and the like. These binders can also be used in combination with crosslinking agents such as amino resins, methylolated melamine resins, alkyl etherified melamine resins, urea resins, and polyisocyanate compounds.

[0054] There is no particular limitation on the blending amount of the binder either. As an example, the content of the binder in the coloring layer 20 is preferably 3 to 40 parts by mass, more preferably 5 to 35 parts by mass, and still more preferably 10 to 30 parts by mass with respect to 100 parts by mass of the solid content constituting the coloring layer 20.

[0055] The thickness of the coloring layer is not particularly limited, but is, for example, 50 to 200 μm.

[0056] The coloring layer may appropriately contain stabilizers (such as Ba-Zn systems, etc.), lubricants, fillers, processing aids, plasticizers, softeners, metal powders, anti-fogging agents, ultraviolet scattering agents or ultraviolet absorbers such as ultraviolet shielding agents, antioxidants, antistatic agents, flame retardants, etc., as necessary.

[0057] <Adhesive layer 30> The adhesive used for the adhesive layer 30 is not particularly limited, and acrylic adhesives, rubber adhesives, silicone adhesives, urethane adhesives, polyester adhesives, styrene-diene block copolymer adhesives, vinyl alkyl ether adhesives, etc. can be used. The above adhesives may be used alone or in combination of two or more.

[0058] As the adhesive, from the viewpoint of adhesion reliability, an acrylic adhesive can be particularly preferably used. The acrylic polymer constituting the acrylic adhesive is formed by using an alkyl (meth)acrylate having adhesiveness as the main monomer component, and if necessary, a monomer copolymerizable with an alkyl (meth)acrylate having cohesiveness (copolymerizable monomer) and a copolymerizable monomer having a crosslinkable functional group.

[0059] Examples of the alkyl (meth)acrylate having adhesiveness include butyl (meth)acrylate, 2-ethylhexyl (meth)acrylate, octyl (meth)acrylate, etc. These may be used alone or in combination of two or more.

[0060] Examples of the copolymerizable monomer having cohesiveness include methyl (meth)acrylate, vinyl acetate, styrene, acrylonitrile, etc. These may be used alone or in combination of two or more.

[0061] Examples of the copolymerizable monomer having a crosslinkable functional group include 2-hydroxyethyl (meth)acrylate, 2-hydroxypropyl (meth)acrylate, (meth)acrylic acid, etc. These may be used alone or in combination of two or more.

[0062] The weight average molecular weight of the acrylic polymer is not particularly limited, but is preferably 100,000 to 1,000,000. The weight average molecular weight is a value in terms of polystyrene measured by gel permeation chromatography (GPC) method.

[0063] The adhesive preferably contains a crosslinking agent in addition to the acrylic polymer. Examples of the crosslinking agent include isocyanate-based crosslinking agents, epoxy-based crosslinking agents, and metal chelate-based crosslinking agents. The addition amount of the crosslinking agent is preferably 0.001 to 10 parts by mass, more preferably 0.005 to 2.0 parts by mass, based on 100 parts by mass of the acrylic polymer.

[0064] In the adhesive layer 30, a light stabilizer, an antioxidant, a colorant, a filler, an antistatic agent, a tackifier, a wetting agent, a leveling agent, a thickening agent, a defoaming agent, a preservative, etc. can be appropriately added as necessary.

[0065] The thickness of the adhesive layer 30 is not particularly limited, but is preferably in the range of 10 to 100 μm from the viewpoints of adhesiveness and thinning of the film.

[0066] The adhesive force of the adhesive layer 30 to the uneven molded product is preferably 10 N / 25 mm or more. The adhesive force to the uneven molded product is measured by a tensile tester at a test speed of 300 mm / min in the 180° direction in accordance with JIS Z0237:2009 after pasting the adhesive layer surface of the marking film 1 on a SUS plate for 24 hours. More specifically, the adhesive force to the uneven molded product is a value measured by the following method; the marking film 1 is left standing in a standard environment (23°C 50% RH) for 1 day, the release liner is peeled off, and the adhesive layer surface is pasted on a SUS304 steel plate. After standing in the standard environment for 24 hours, the adhesive force is measured in accordance with JIS Z0237:2009. Specifically, the film is peeled off at a test speed of 300 mm / min in the 180° direction by a tensile tester, and the adhesive force is measured. The numerical value is converted into the peeling force per 25 mm of the film width (N / 25 mm).

[0067] <Release liner 40> The release liner 40 is a member having a function of protecting the adhesive layer 30 and preventing a decrease in adhesiveness. And the release liner 40 is peeled off from the marking film 1 when pasting on the uneven molded product. For this reason, the marking film 1 in the present embodiment also includes those without the release liner 40.

[0068] The release liner 40 is not particularly limited, and examples thereof include plastic films such as polyester films such as polyethylene terephthalate, polybutylene terephthalate, and polyethylene naphthalate, and polyolefin films such as polypropylene and polyethylene; and papers such as high-quality paper, glassine paper, kraft paper, and clay-coated paper.

[0069] The thickness of the release liner 40 is usually about 10 to 400 μm. Further, a layer made of a release agent composed of silicone or the like for improving the releasability of the adhesive layer 30 may be provided on the surface of the release liner 40. When such a layer is provided, the thickness of the layer is usually about 0.01 to 5 μm.

[0070] The method of stretching the marking film 1 is not particularly limited, and examples thereof include TOM molding, insert molding, press molding, and in-mold molding.

[0071] Next, with reference to FIGS. 2 to 4, the effects of the marking film 1 according to the present embodiment will be described. FIG. 2 is a schematic cross-sectional view showing the state of the marking film 1 according to the present embodiment after stretching. FIG. 3 is a schematic cross-sectional view showing the state of the marking film 900 according to the comparative example after stretching. FIG. 4 is a diagram for explaining the effects of the marking film 1 according to the present embodiment.

[0072] For example, as shown in FIG. 3, in the case where the transparent layer 910 does not contain transparent particles, when stretched by 200%, the uneven height H decreases and the interval L between adjacent protrusions widens, resulting in a decrease in the matte feeling of the marking film 900. When the matte feeling decreases, glossiness occurs.

[0073] On the other hand, according to the marking film 1 according to the present embodiment, since the transparent layer 10 contains the transparent particles 11, when the marking film 1 is stretched, as shown in FIG. 2, the transparent particles 11 suppress the decrease in the surface unevenness height H, and new convex portions 10A and 10B are formed by the transparent particles 11 in the concave portions between adjacent convex portions with an increased interval. Therefore, even if the marking film 1 according to the present embodiment is stretched, a decrease in the matte feeling can be suppressed.

[0074] Hereinafter, with reference to FIG. 4, the mechanism for suppressing the decrease in the matte feeling described above will be described in detail. Note that the numerical values in the following description are examples, and the present invention is not limited to the numerical values.

[0075] FIG. 4(A) is a cross-sectional view showing the transparent layer 910 in the marking film 900 according to the comparative example. FIG. 4(B) is a cross-sectional view showing the transparent layer 10 in the marking film 1 according to the embodiment. FIG. 4(C) is a cross-sectional view showing the transparent layer 10 in the marking film 1 according to the embodiment.

[0076] The thickness of the transparent layers 10 and 910 is, for example, 40 μm. The marking film 900 according to the comparative example does not contain transparent particles. The marking film 1 according to the embodiment shown in FIG. 4(B) contains one transparent particle 11 having a diameter of 10 μm. The marking film 1 according to the embodiment shown in FIG. 4(C) contains two transparent particles 11 having a diameter of 10 μm in the stacking direction (vertical direction).

[0077] In this state, when the marking film 900 according to the comparative example is stretched by 200%, as shown in FIG. 4(A), the thickness of the transparent layer 910 decreases from 40 μm to 20 μm, the height of the convex portion decreases, and the matte feeling decreases.

[0078] On the other hand, when the marking film 1 according to the embodiment shown in FIG. 4(B) is stretched by 200%, the thickness of the 30-μm transparent layer 10 where no transparent particles 11 are included in the 40-μm transparent layer 10 decreases to 15 μm, while the thickness of the 10-μm transparent layer 10 where the transparent particles 11 are included remains substantially 10 μm. Therefore, the overall thickness of the transparent layer 10 becomes 25 μm, and since the thickness increases by 5 μm compared to the marking film 900 according to the comparative example, a decrease in the matte feeling can be suppressed.

[0079] Furthermore, when the marking film 1 according to the embodiment shown in FIG. 4(C) is stretched by 200%, the thickness of the 20-μm transparent layer 10 where no transparent particles 111 are included in the 40-μm transparent layer 10 decreases to 10 μm, while the thickness of the 20-μm transparent layer 10 where the transparent particles 11 are included remains substantially 20 μm. Therefore, the overall thickness of the transparent layer becomes 30 μm, and since the thickness increases by 10 μm compared to the marking film 900 according to the comparative example, a further decrease in the matte feeling can be suppressed.

[0080] <Example> Next, the effects of the present invention will be described using the following comparative examples and examples.

[0081] After preparing a dispersion in which a urethane resin and transparent particles are dispersed in a solvent, this was coated on a process paper (EV130TPD, manufactured by Lintec Corporation), and heated and dried to form a 40-μm-thick transparent layer 10.

[0082] As the transparent particles 11, spherical microparticles of crosslinked polymethyl methacrylate, Tech Polymer MB30X-8 (average particle diameter: 8 μm, manufactured by Sekisui Chemical Co., Ltd.) were used.

[0083] Next, after preparing a dispersion in which 100 parts by weight of an acrylic urethane resin and 10 parts by weight of carbon black [manufactured by Mitsubishi Chemical Corporation, trade name "RCF#44", average primary particle diameter 24 nm] are dispersed in a solvent, this was coated on the above transparent layer 10 and heated and dried to obtain a 30-μm-thick colored layer 20.

[0084] As the adhesive layer 30, an acrylic resin of 30 μm was used.

[0085] As the release liner 40, polyethylene terephthalate (PET) of 50 μm was used. And, 100 nm of a silicone release agent was applied to the surface of the above laminate on the side of the release liner 40.

[0086] As a comparative example, a marking film in which transparent particles are not contained in the transparent layer was prepared. As Example 1, a marking film in which 5% by mass of transparent particles are contained in the transparent layer was prepared. As Example 2, a marking film in which 15% by mass of transparent particles are contained in the transparent layer was prepared. As Example 3, a marking film in which 25% by mass of transparent particles are contained in the transparent layer was prepared. As Example 4, a marking film in which 35% by mass of transparent particles are contained in the transparent layer was prepared.

[0087] Table 1 shows the results of the surface roughness Rz and the 60% specular glossiness of the marking films according to the comparative example, Example 1, Example 2, Example 3, and Example 4 after being stretched by 150% and after being stretched by 200%.

[0088]

Table 1

[0089] It was found from Table 1 that the decrease in the matte feeling is suppressed as the addition amount of the transparent particles to the transparent layer increases.

Explanation of symbols

[0090] 1 Marking film, 10 Transparent layer, 11 Transparent particles, 20 Coloring layer, 30 Adhesive layer, 40 Release liner.

Claims

1. It has an adhesive layer, a colored layer, and a transparent layer adjacent to the colored layer, The transparent layer contains transparent particles and at least one selected from the group consisting of a urethane resin, a fluorine-containing resin, and an acrylic resin, The glossiness is 1 to 50, The colored layer is a concealing layer, The transparent layer has an uneven shape, The marking film, wherein the thickness of the transparent layer is 30 to 50 μm and the volume average particle diameter of the transparent particles is 1 to 30 μm.

2. The marking film according to claim 1, wherein the ten-point average surface roughness on the side of the transparent layer opposite to the adhesive layer is 0.1 to 30 μm.

3. The marking film according to claim 1 or 2, wherein the glossiness after 200% elongation is within ±20 with respect to the glossiness before elongation.

4. The marking film according to any one of claims 1 to 3, wherein the transparent particles are spherical.

5. The marking film according to any one of claims 1 to 4, wherein the addition amount of the transparent particles is 5 to 35% by mass of the transparent layer.

6. A method for manufacturing a marking film having an adhesive layer, a colored layer, and a transparent layer adjacent to the colored layer, A method for manufacturing a marking film, wherein a dispersion liquid in which at least one selected from the group consisting of a urethane resin, a fluorine-containing resin, and an acrylic resin and transparent particles are dispersed in a solvent is coated on a process paper having an uneven shape to form the transparent layer.

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