Colored adhesive tape

Abstract

To provide a colored adhesive tape having a more even surface, and stable in a gross value.SOLUTION: A colored adhesive tap 1 includes a release film 6, an adhesive layer 5, a coloring layer 4, a resin film layer 3, and a delustering layer 2 laminated in this order, where the delustering layer 2 comprises a polyester-based resin, isocyanate, and a delustering agent that contains silica as main constituents, and has a thickness of 0.5 μm or more and 3 μm or less, and the colored layer 4 includes a resin, isocyanate, and a pigment containing carbon black as main constituents.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a colored adhesive tape. [Background technology]

[0002] Colored films and colored adhesive tapes have traditionally been used in various industrial fields for purposes such as decoration, display, concealment, reflection, and light blocking. In particular, in fields where miniaturization and thinning are highly desired, such as personal computers, digital video cameras, and portable electronic devices, including electronic organizers, mobile phones, PHS (Personal Handyphone Systems), smartphones, game consoles, and e-books, various colored adhesive tapes are used to secure and protect components while simultaneously providing a light-blocking effect through black coloring, improving brightness through white coloring, and concealing defects in the appearance of components (such as unevenness and small defects) and improving their appearance, thereby reducing the number of components used. Furthermore, adhesive sheets are sometimes used in portable electronic devices to protect graphite sheets installed for heat dissipation purposes (see, for example, Patent Document 1). [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Patent No. 6789013 Summary of the Invention [Problem to be solved by the invention]

[0004] The pressure-sensitive adhesive sheet described in Patent Document 1 has a matte layer as the outermost layer, and has a laminated structure of "matte layer / black colored layer / PET film / adhesive layer / release film." In this type of pressure-sensitive adhesive sheet having a laminated structure of "matte layer / black colored layer / PET film / adhesive layer / release film," the matte layer is formed by applying a resin or the like that will become the matte layer to the black colored layer through gravure printing. Therefore, when forming the matte layer, the surface of the black colored layer is roughened by the solvent, making it difficult to obtain a matte layer with a uniform surface. This results in an unstable gloss value for the matte layer.

[0005] The present invention has been made in view of the above points, and has as its object to provide a colored adhesive tape having a more uniform surface and a stable gloss value. [Means for solving the problem]

[0006] According to one embodiment of the present invention, there is provided a colored adhesive tape comprising a release film, an adhesive layer, a colored layer, a resin film layer, and a matte layer laminated in this order, wherein the matte layer is primarily composed of a polyester resin, an isocyanate, and a matte agent, the matte agent containing silica, and has a thickness of 0.5 μm or more and 3 μm or less, and the colored layer is primarily composed of a resin, an isocyanate, and a pigment containing carbon black. [Effects of the Invention]

[0007] According to one aspect of the present invention, a colored pressure-sensitive adhesive tape having a more uniform surface and a stable gloss value can be obtained. [Brief explanation of the drawings]

[0008] [Figure 1] 1 is a cross-sectional view schematically illustrating an example of a colored adhesive tape according to an embodiment of the present invention. [Figure 2] 1 is a cross-sectional view schematically showing an example in which a colored adhesive tape according to an embodiment of the present invention is applied to a heat dissipation sheet or a magnetic sheet. DETAILED DESCRIPTION OF THE INVENTION

[0009] Next, an embodiment of the present invention will be described below with reference to the drawings. The drawings are schematic, and the relationship between thickness and planar dimensions, the thickness ratio of each layer, etc., differ from the actual ones. Furthermore, the embodiments shown below are merely examples of configurations for embodying the technical idea of ​​the present invention, and the technical idea of ​​the present invention is not limited to the materials, shapes, structures, etc. of the components described below. The technical idea of ​​the present invention can be modified in various ways within the technical scope defined by the claims.

[0010] (Composition of colored adhesive tape) Fig. 1 is a cross-sectional view schematically showing a colored adhesive tape 1 according to an embodiment of the present invention. As shown in Fig. 1, the colored adhesive tape 1 includes a matte layer 2, a resin film layer 3, a colored layer 4, an adhesive layer 5, and a release film 6, and the colored adhesive tape 1 is formed by laminating these layers in this order from the release film 6 side.

[0011] (Matte layer) The matte layer 2 is a layer whose main components are a polyester resin, an isocyanate, and a matte agent, and which also contains silica as the matte agent. The isocyanate may be, for example, an aliphatic isocyanate such as HDI (hexamethylene diisocyanate). By including an isocyanate in the matte layer 2, adhesion to the resin film layer 3 serving as the substrate can be improved. To achieve a sufficient matte finish, the thickness of the matte layer 2 is preferably 0.5 μm or more. While there is no upper limit to the thickness of the matte layer 2, a thickness of 3 μm is sufficient to achieve a sufficient matte finish, so the thickness is preferably 3 μm or less. In this specification, a component that accounts for 50% by weight or more of the components in a layer is referred to as a "main component," and "mainly composed of a polyester resin, an isocyanate, and a matting agent" means that the total content of the polyester resin, the isocyanate, and the matting agent exceeds 50% by weight of the components in the layer.

[0012] The matte layer 2 may be colored or uncolored. Coloring the matte layer 2 can improve the design of the colored pressure-sensitive adhesive tape 1. When the matte layer 2 is colored, it is colored, for example, by mixing a pigment into a paint for forming the matte layer 2, the paint containing a polyester resin, an isocyanate, and a matting agent as main components. Barium sulfate, for example, is sometimes used as a matting agent. However, if only barium sulfate is added as the matting agent to the paint for forming the matte layer 2, it is difficult to achieve a matte finish when the matte layer 2 is directly coated on a resin film layer 3 made of a PET resin, as described below. Furthermore, barium sulfate has a high specific gravity, is prone to settling, is relatively difficult to coat, and has a small particle size, so a large amount of barium sulfate must be added to achieve a matte finish. In this embodiment, silica, which has a relatively low specific gravity and a relatively large particle size, is used as the matting agent, so a sufficient matte finish can be achieved with a smaller amount added.

[0013] The matte layer 2 preferably has a 60° gloss value of 3 or less on the surface opposite the resin film layer 3. A surface with a limited gloss value can be alcohol-resistant. "Alcohol-resistant" refers to a surface that is inhibited from undergoing changes in appearance (e.g., changes in gloss value, color, or light-blocking properties) when exposed to alcohol (e.g., ethanol). This allows for the surface of the colored adhesive tape 1, i.e., the surface of the matte layer 2 opposite the resin film layer 3, to be wiped clean with alcohol without risking a loss of design. Therefore, stain resistance and design can be ensured.

[0014] Furthermore, from the viewpoint of imparting antifouling properties to the colored pressure-sensitive adhesive tape 1, it is preferable that the surface of the matte layer 2 opposite to the resin film layer 3 has a water contact angle of 80° or more. The water contact angle may be measured using a commercially available contact angle measuring device in accordance with JIS R 3257:1999. For example, the measurement can be performed under the following conditions. Water contact angle measurement conditions Measuring device: Contact angle measuring device FACE CA-X type (manufactured by Kyowa Kaimen Kagaku Co., Ltd.) Measurement atmosphere: 23°C, 50% RH Measurement liquid: Distilled water Measurement time: 1500ms after droplet deposition

[0015] (Resin film layer) The resin film layer 3 is a layer used as a base material and is formed from, for example, PET (polyethylene terephthalate) resin, PI (polyimide) resin, or the like, but is not particularly limited thereto. If the thickness of the resin film layer 3 is 1 μm or more, the colored layer and matte layer can be laminated well. If the thickness is 3 μm or less, the colored adhesive tape 1 is sufficiently soft, allowing for fine processing during use. The width of the resin film layer 3 is not limited, but is, for example, 1050 mm.

[0016] (colored layer) The colored layer 4 is a black colored layer and contains, as its main components, a resin, an isocyanate, and a pigment containing carbon black. The resin is preferably a polyester resin or an acrylic resin. The isocyanate may be, for example, an aliphatic isocyanate such as HDI (hexamethylene diisocyanate). By including an isocyanate in the colored layer 4, the adhesion to the resin film layer 3 can be improved. The colored layer 4 contains carbon black, which is well known as a colorant. The colored layer 4 may also contain colorants of other colors for color matching, etc. The phrase "mainly composed of a resin, an isocyanate, and a pigment containing carbon black" means that the total content of the resin, the isocyanate, and the pigment containing carbon black exceeds 50% by weight of the components in the layer. From the viewpoint of ensuring sufficient hiding power, the colored layer 4 preferably has a thickness of 2 μm or more and 4 μm or less. When the thickness of the colored layer 4 is 4 μm or more, the degree of change in hiding power due to the thickness is relatively small, and the change in hiding power obtained with an increase in the thickness of the colored layer 4 is small. Therefore, by setting the thickness of the colored layer 4 to 2 μm or more and 4 μm or less, sufficient hiding power can be obtained while suppressing an increase in the thickness of the colored layer 4.

[0017] (Adhesive layer) The adhesive constituting the adhesive layer 5 is not particularly limited, and examples thereof include acrylic adhesives, urethane adhesives, synthetic rubber adhesives, polyester adhesives, silicone adhesives, etc. Among these, acrylic adhesives containing a (meth)acrylic polymer are preferred from the viewpoints of ease of adjusting the molecular weight, degree of crosslinking, etc., and excellent heat resistance, weather resistance, cost, etc. The (meth)acrylic polymer is a polymer containing structural units derived from a (meth)acrylic monomer.

[0018] The (meth)acrylic monomer is not particularly limited, and examples thereof include methyl (meth)acrylate, ethyl (meth)acrylate, propyl (meth)acrylate, butyl (meth)acrylate, isobutyl (meth)acrylate, tertiary butyl (meth)acrylate, pentyl (meth)acrylate, hexyl (meth)acrylate, heptyl (meth)acrylate, octyl (meth)acrylate, isooctyl (meth)acrylate, 2-octyl (meth)acrylate, 2-ethylhexyl (meth)acrylate, nonyl (meth)acrylate, isononyl (meth)acrylate, decyl (meth)acrylate, lauryl (meth)acrylate, isomyristyl (meth)acrylate, stearyl (meth)acrylate, isostearyl (meth)acrylate, cyclohexyl (meth)acrylate, and isobornyl (meth)acrylate. These (meth)acrylic monomers may be used alone or in combination of two or more.

[0019] The (meth)acrylic polymer preferably further contains a structure derived from a crosslinkable functional group-containing monomer. When the (meth)acrylic polymer contains a structure derived from the crosslinkable functional group-containing monomer, the cohesive strength of the adhesive layer 5 can be adjusted by crosslinking the crosslinkable functional group, thereby improving heat resistance. The crosslinkable functional group may or may not be crosslinked, but is preferably crosslinked. However, even if the structure remains uncrosslinked, the cohesive strength of the adhesive layer 5 is increased due to the interaction between the functional groups.

[0020] Examples of the crosslinkable functional group-containing monomer include monomers containing a carboxyl group, a hydroxyl group, an epoxy group, a double bond, a triple bond, an amino group, an amide group, a nitrile group, etc. These crosslinkable functional group-containing monomers may be used alone or in combination of two or more. Among these, at least one selected from the group consisting of a carboxyl group-containing monomer and a hydroxyl group-containing monomer is preferred. Hydroxyl group-containing monomers are more preferred because the heat resistance of the adhesive layer 5 can be easily adjusted by crosslinking with an isocyanate-based crosslinking agent. The crosslinkable functional group-containing monomer may further contain an alkyl group, an ether group, a carbonyl group, an ester group, a carbonate group, an amide group, a urethane group, or the like.

[0021] Examples of the carboxyl group-containing monomer include (meth)acrylic acid-based monomers such as (meth)acrylic acid. Examples of the hydroxyl group-containing monomer include 4-hydroxybutyl (meth)acrylate, 2-hydroxyethyl (meth)acrylate, etc. Examples of the epoxy group-containing monomer include glycidyl (meth)acrylate, etc. Examples of the double bond-containing monomer include allyl (meth)acrylate, hexanediol di(meth)acrylate, etc. Examples of the triple bond-containing monomer include propargyl (meth)acrylate, etc. Examples of the amide group-containing monomer include (meth)acrylamide, etc.

[0022] The content of the structure derived from the monomer having a crosslinkable functional group in the (meth)acrylic polymer is not particularly limited, but the lower limit of the content of the structural unit is preferably 0.05 wt % and the upper limit is preferably 30 wt % from the viewpoint of adjusting the adhesive strength and heat resistance of the adhesive layer 5. The lower limit of the content of the structural unit is more preferably 0.1 wt % and the upper limit is more preferably 25 wt %. Furthermore, the content of the structure derived from the hydroxyl group-containing monomer in the (meth)acrylic polymer is not particularly limited, but the lower limit of the content of the structural unit is preferably 0.05 wt % and the upper limit is preferably 5 wt % from the viewpoint of adjusting the adhesive strength and heat resistance of the adhesive layer 5. The lower limit of the content of the structural unit is more preferably 0.08 wt % and the upper limit is more preferably 1 wt %.

[0023] The (meth)acrylic polymer preferably contains a structural unit derived from a monomer containing bio-derived carbon. When the (meth)acrylic polymer contains a structural unit derived from a monomer containing bio-derived carbon, the content of bio-derived carbon in the pressure-sensitive adhesive layer 5 increases, and the environmental impact of the resulting pressure-sensitive adhesive tape can be further reduced. In addition, in this specification, "containing carbon derived from a living organism" means that the bio-based carbon content of the compound measured according to ASTM D6866-22 is 1% or more. To obtain the (meth)acrylic polymer, a monomer mixture containing the (meth)acrylic monomer, the crosslinkable functional group-containing monomer, etc. may be copolymerized by radical reaction in the presence of a polymerization initiator. As a method for radically reacting the monomer mixture, i.e., a polymerization method, a conventionally known method may be used, such as solution polymerization (boiling point polymerization or constant temperature polymerization), emulsion polymerization, suspension polymerization, bulk polymerization, etc.

[0024] The weight-average molecular weight (Mw) of the (meth)acrylic polymer is not particularly limited, but a preferred upper limit is 2,000,000. If the weight-average molecular weight (Mw) is 2,000,000 or less, the initial adhesion to the adherend will be good even if the adhesive layer 5 is thin. A more preferred upper limit of the weight-average molecular weight (Mw) is 1,500,000, and an even more preferred upper limit is 1,300,000. The lower limit of the weight average molecular weight (Mw) is not particularly limited, but from the viewpoint of the adhesive strength and shape retention of the adhesive layer 5, the lower limit is preferably 400,000, and more preferably 500,000. The weight-average molecular weight of the (meth)acrylic polymer can be determined, for example, by gel permeation chromatography (GPC) in terms of standard polystyrene. More specifically, the measurement can be performed using a Water Corporation "2690 Separations Module" measuring instrument, a Showa Denko Corporation "GPC KF-806L" column, ethyl acetate as a solvent, a sample flow rate of 1 mL / min, and a column temperature of 40°C.

[0025] The adhesive layer 5 may contain a tackifying resin. Examples of the tackifying resin include rosin ester resins, hydrogenated rosin resins, terpene resins, terpene phenol resins, coumarone-indene resins, alicyclic saturated hydrocarbon resins, C5 petroleum resins, C9 petroleum resins, C5-C9 copolymer petroleum resins, etc. These tackifying resins may be used alone or in combination of two or more. The content of the tackifier resin is not particularly limited, but from the viewpoint of ensuring good initial adhesion to the substrate even when the adhesive layer 5 is thin and exhibiting sufficient adhesive strength, a preferred upper limit is 50 parts by weight, a preferred lower limit is 10 parts by weight, a more preferred upper limit is 35 parts by weight, and a more preferred lower limit is 20 parts by weight per 100 parts by weight of the resin (e.g., a (meth)acrylic polymer) that is the main component of the adhesive layer 5.

[0026] The adhesive layer 5 may be crosslinked with a crosslinking agent. The crosslinking agent is not particularly limited and is appropriately selected depending on the adhesive constituting the adhesive layer 5. For example, when the adhesive constituting the adhesive layer 5 is an acrylic adhesive, examples of the crosslinking agent include an isocyanate crosslinking agent, an epoxy crosslinking agent, an aziridine crosslinking agent, and a metal chelate crosslinking agent. Among these, any of an isocyanate crosslinking agent, an aziridine crosslinking agent, and an epoxy crosslinking agent is preferred, as these provide the adhesive tape with excellent adhesion to the adherend, and an isocyanate crosslinking agent is preferred. These may be used alone, or two or more types may be used in combination. Examples of commercially available isocyanate crosslinking agents include Coronate HX (manufactured by Nippon Polyurethane Co., Ltd.) and Takenate D-101E (manufactured by Mitsui Chemicals, Inc.). Examples of commercially available epoxy crosslinking agents include Tetrad-C and Tetrad-X (manufactured by Mitsubishi Gas Chemical Company, Inc.). Examples of commercially available metal chelate crosslinking agents include Aluminum Chelate A (manufactured by Kawaken Fine Chemicals Co., Ltd.). The content of the crosslinking agent is not particularly limited, but the preferred lower limit is 0.1 parts by weight and the preferred upper limit is 5 parts by weight, more preferably 0.3 parts by weight and more preferably 3 parts by weight, relative to 100 parts by weight of the adhesive solid content.

[0027] The adhesive layer 5 may further contain known additives such as inorganic fillers such as fumed silica, colorants such as pigments, plasticizers, resins, surfactants, waxes, particulate fillers, etc. These additives may be used alone or in combination of two or more. The gel fraction of the adhesive layer 5 is not particularly limited, but a preferred lower limit is 10 wt % and a preferred upper limit is 70 wt %. If the gel fraction is 10 wt % or more, the heat resistance of the adhesive layer 5 is improved. If the gel fraction is 70 wt % or less, the adhesive layer 5 will exhibit sufficient adhesive strength even if it is thin. A more preferred lower limit of the gel fraction is 15 wt % and a more preferred upper limit is 65 wt %, and an even more preferred lower limit is 20 wt % and an even more preferred upper limit is 60 wt %.

[0028] The gel fraction of the adhesive layer 5 can be measured by the following method. 0.1 g of the adhesive layer (adhesive composition) alone was removed from the colored adhesive tape, immersed in 50 mL of ethyl acetate, and shaken in a shaker at 23°C and 200 rpm for 24 hours. After shaking, the ethyl acetate and the adhesive composition that had absorbed the ethyl acetate and swollen were separated using a metal mesh (opening #200 mesh). The separated adhesive composition was dried at 110°C for 1 hour. The weight of the dried adhesive composition including the metal mesh was measured, and the gel fraction of the adhesive layer was calculated using the following formula (1). Gel fraction (wt%) = 100 × (W1 - W2) / W0 (1) (W0: initial weight of adhesive composition, W1: weight of adhesive composition including metal mesh after drying, W2: initial weight of metal mesh)

[0029] However, if the adhesive layer does not dissolve completely in ethyl acetate, a solvent such as toluene, hexane, water, etc. is used instead of ethyl acetate. Specifically, if the adhesive layer contains, for example, a styrene-based elastomer, toluene or hexane is used, and if it contains polyvinyl alcohol, hot water at 90°C is used. The glass transition temperature (Tg) of the adhesive layer 5 is not particularly limited, but from the viewpoint of ensuring good adhesion and heat resistance even when the adhesive layer 5 is thin, the lower limit is preferably −70° C. and the upper limit is preferably 25° C. The glass transition temperature (Tg) is more preferably −65° C. and more preferably 15° C.

[0030] The glass transition temperature (Tg) of the adhesive layer 5 can be determined, for example, by measuring the storage modulus G' and loss modulus G" at each temperature using a polymer dynamic viscoelasticity measuring device "itkDVA-200" (manufactured by IT Measurement Control Co., Ltd.) under the following conditions, calculating tan δ at each temperature, and determining the temperature at which tan δ reaches its peak value as the glass transition temperature (Tg). Measurement mode: Shear Heating rate: 5°C / min Measurement temperature range: -30℃~150℃ Setting distortion: 0.1% Frequency: 1Hz

[0031] The thickness of the adhesive layer 5 is not particularly limited, but a preferred lower limit is 1 μm and a preferred upper limit is 4 μm. If the thickness of the adhesive layer 5 is less than 1 μm, the adhesiveness of the adhesive layer 5 decreases and the adhesive layer 5 may peel off from the adherend. If the thickness of the adhesive layer 5 exceeds 4 μm, the colored adhesive tape 1 becomes too thick and may not be suitable for use in mobile electronic devices. A more preferred lower limit of the thickness is 1.5 μm and a more preferred upper limit is 3.5 μm.

[0032] (Release film) The release film 6 is intended to protect the adhesive layer 5 until it is used, and its material is not particularly limited. The surface of the release film 6 that comes into contact with the adhesive layer 5 is a release-treated surface, and is made of, for example, a PET film coated with a silicone release agent. Furthermore, the average height Rc of the roughness curve elements on the surface of the release film 6 opposite the adhesive layer 5 is preferably greater than 500 nm. When the average height Rc of the roughness curve elements is greater than 500 nm, the frictional force with the roll during transport of the colored adhesive tape 1 is reduced, and the occurrence of meandering and wrinkles can be suppressed.

[0033] (Colored adhesive tape) By setting the total thickness of the colored adhesive tape 1 to 4.5 μm or more, the thickness necessary for each constituent layer to exhibit its function can be ensured. Furthermore, the total thickness of the colored adhesive tape 1 is preferably 13 μm or less, more preferably 10 μm or less. This allows for precise adhesion of small components. The total thickness of the colored adhesive tape 1 here refers to the overall thickness of the laminate 1′ consisting of the adhesive layer 5, colored layer 4, resin film layer 3, and matte layer 2, excluding the release film 6.

[0034] From the viewpoint of obtaining sufficient light-blocking properties and masking properties (concealment properties) for the adherend, the colored adhesive tape 1 preferably has a light transmittance of 5% or less for the laminate 1', which is made up of the matte layer 2, resin film layer 3, colored layer 4, and adhesive layer 5 and which is composed of layers excluding the release film 6, among the laminates constituting the colored adhesive tape 1. Such a colored adhesive tape 1 can appropriately reflect the color of the adherend (e.g., graphite sheet) and can impart the desired color, texture, and design. The colored adhesive tape 1 having such a configuration is extremely thin yet has good heat resistance, and therefore can be particularly suitably used as a tape for surface protection, for example, by attaching the adhesive layer 5 side of the colored adhesive tape 1', with the release film 6 removed from the colored adhesive tape 1, to the surface of a heat dissipation sheet or magnetic sheet 10 that is attached to electronic components that generate heat during use, as shown in Figure 2.

[0035] (Manufacturing method of colored adhesive tape) The method for producing the colored adhesive tape 1 is not particularly limited, and examples thereof include the following methods. First, the colored layer 4 is formed on one surface of the resin film layer 3. For example, a colored layer paint containing carbon black is applied to one surface of the resin film layer 3 by gravure printing or the like to form the colored layer 4. Next, a matte layer paint is applied to the other surface of the resin film layer 3 by gravure printing or the like to form the matte layer 2.

[0036] Next, the adhesive layer 5 is formed by a casting method or the like on the release-treated surface of the release film 6. Examples of the casting method include a method in which a resin solution that will become the adhesive layer 5 is applied using a gravure method, a roll coating method, or the like, and then the applied resin solution is heated and dried. Next, the surface of the colored layer 4 opposite to the resin film layer 3 and the surface of the adhesive layer 5 opposite to the release film 6 are bonded together. As a result, a colored adhesive tape 1 is formed in which the release film 6, adhesive layer 5, colored layer 4, resin film layer 3, and matte layer 2 are laminated in this order.

[0037] (Effects of the colored adhesive tape according to this embodiment) The colored adhesive tape 1 has a matte layer 2 formed on one side of a resin film layer 3 and a colored layer 4 formed on the other side. This prevents the surface of the colored adhesive tape 1, i.e., the side of the matte layer 2 opposite the resin film layer 3, from becoming uneven, resulting in a colored adhesive tape 1 with a uniform surface. In other words, if a colored adhesive tape were formed with a laminated structure of "matte layer 2 / colored layer 4 / resin film layer 3 / adhesive layer 5 / release film 6," when the colored layer 4 was formed on the resin film layer 3 and then a paint for forming the matte layer 2 was applied to the colored layer 4 by gravure printing, the surface of the colored layer 4 would be roughened by the solvent contained in the paint for forming the matte layer 2. As a result, the surface of the matte layer 2 formed on the colored layer 4 would be uneven or the gloss value would be unstable. In contrast, in this embodiment, the colored adhesive tape 1 is configured so that the matte layer 2 / resin film layer 3 / colored layer 4 / adhesive layer 5 / release film 6 are laminated in this order. Therefore, one side of the matte layer 2 becomes the surface of the colored adhesive tape 1, and the matte layer 2 is formed on the resin film layer 3. The surface of the resin film layer 3 is flat, and it is unlikely that the surface of the resin film layer 3 will be roughened when the matte layer 2 is formed on the surface of the resin film layer 3. This prevents the surface of the matte layer 2 formed on the surface of the resin film layer 3 from becoming uneven due to the surface shape of the resin film layer 3, and as a result, a colored adhesive tape with a uniform surface on the matte layer 2 side can be obtained.

[0038] In addition, as a method for preventing unevenness in the surface of the colored adhesive tape, it is possible to obtain a matte finish by adding a matting agent to the colored layer without providing the matte layer 2. However, in this case, there is a problem that the gloss value of the colored layer is not stable, and since the matting agent and pigment in the colored layer are mixed, the gloss value of the colored layer is likely to change depending on the thickness of the colored layer and how the colored layer is dried.

[0039] Furthermore, if the colored adhesive tape is formed into a laminated structure of "resin film layer 3 / colored layer 4 / adhesive layer 5 / release film 6" without providing the matte layer 2, a matte finish cannot be obtained. If the colored adhesive tape is formed into a laminated structure of "matte layer 2 / resin film layer 3 / adhesive layer 5 with added colorant / release film 6", it is difficult to achieve both adhesive performance and black density in the adhesive layer 5. Furthermore, if the colored adhesive tape is formed into a laminated structure of "matte layer 2 / resin film layer 3 with added colorant / adhesive layer 5 / release film 6", there is the problem that sufficient black density cannot be obtained.

[0040] As described above, the colored adhesive tape 1 in this embodiment can be obtained as a colored adhesive tape with a uniform surface shape by laminating each layer in an appropriate order without adding colorant to other layers. [Example]

[0041] Examples of the colored adhesive tape according to the present invention will be described below. However, the present invention is not limited to the following examples. Colored adhesive tapes of Examples 1 to 12 and Comparative Examples 1 to 3 were prepared as colored adhesive tapes for evaluation and evaluated according to the following procedure. The configurations of the colored adhesive tapes for evaluation are shown in Table 1-1, Table 1-2, and Table 2, and the evaluation results of the colored adhesive tapes for evaluation are shown in Table 3. Each colored adhesive tape was prepared in A4 size.

[0042] [Table 1-1]

[0043] [Table 1-2]

[0044] [Table 2]

[0045] Example 1 (1) Preparation of acrylic copolymer A (solution polymerization) Ethyl acetate was added to the reaction vessel as the polymerization solvent, and nitrogen was bubbled through. The reaction vessel was then heated while nitrogen was flowing in to initiate reflux. Next, a polymerization initiator solution prepared by diluting 0.1 parts by weight of azobisisobutyronitrile 10 times with ethyl acetate was added to the reaction vessel, and 56.9 parts by weight of butyl acrylate, 40 parts by weight of 2-ethylhexyl acrylate, 3 parts by weight of acrylic acid, and 0.1 parts by weight of 2-hydroxyethyl acrylate were added dropwise over two hours. After the dropwise addition, a polymerization initiator solution prepared by diluting 0.1 parts by weight of azobisisobutyronitrile 10 times with ethyl acetate was added again to the reaction vessel, and the polymerization reaction was carried out for four hours, yielding a solution containing acrylic copolymer A.

[0046] The obtained acrylic copolymer A-containing solution was diluted 50 times with tetrahydrofuran (THF), and the resulting diluted solution was filtered through a filter (material: polytetrafluoroethylene, pore size: 0.2 μm) to prepare a measurement sample. This measurement sample was supplied to a gel permeation chromatograph (Waters, 2690 Separations Model) and subjected to GPC measurement under conditions of a sample flow rate of 1 mL / min and a column temperature of 40°C. The polystyrene-equivalent molecular weight of acrylic copolymer A was measured, and the weight-average molecular weight was found to be 1,280,000. To the obtained acrylic copolymer A-containing solution, 25 parts by weight of polymerized rosin ester (Pensel D-135, manufactured by Arakawa Chemical Industries, Ltd.) as a tackifying resin and 4 parts by weight of an isocyanate-based crosslinking agent (Takenate D-101E, manufactured by Mitsui Chemicals, Inc.) were added per 100 parts by weight of acrylic copolymer A to obtain an acrylic adhesive (hereinafter referred to as acrylic adhesive a).

[0047] (2) Manufacture of colored adhesive tape A PET film was prepared as the resin film layer, and the paint for forming the colored layer was applied to one side of the resin film layer using a bar coater. The wire bar used was #8. After application, the coating was dried in an oven at 80°C for 2 minutes to form a colored layer. The thickness of the colored layer after drying was 2.5 μm. Next, a matte layer coating was applied to the other side of the resin film layer with the colored layer formed on one side using a bar coater. The wire bar used was #5. After coating, the coating was dried in an 80°C oven for 2 minutes and then aged in a 40°C oven for 1 day to form a matte layer. The matte layer thickness after aging was 1.5 μm.

[0048] Next, a 38 μm thick PET film with a silicone release-treated surface was prepared as a release film, and an acrylic adhesive was applied to the silicone release-treated surface of the release film using an applicator. After application, the film was dried in an oven at 110°C for 2 minutes to form an adhesive layer. The adhesive layer had a thickness of 2 μm. Next, the colored layer side of the resin film layer and the adhesive layer side of the release film were placed facing each other, and the two were laminated together with a roller, followed by aging for 2 days in an oven at 40° C. This produced a colored adhesive tape consisting of a laminate of "matte layer / resin film layer / colored layer / adhesive layer / release film."

[0049] At this time, the following materials were used as the paint for forming the matte layer, the paint for forming the resin film layer and the colored layer, the acrylic adhesive for forming the adhesive layer, and the release film. Matte layer Resin: Polyester resin (Vylon 200, manufactured by Toyobo Co., Ltd.) Isocyanate: Aliphatic Isocyanate HDI Matting agent: Silica (Silo Hobic 100, manufactured by Fuji Silysia Chemical Co., Ltd.) Pigment: None Solvent: "Toluene:MEK=1:1" Formula: Resin: Isocyanate: Matting agent: Solvent: Pigment = 20:3:5:72:0

[0050] Resin film layer 2 μm polyester film (Lumirror 2-F51, manufactured by Toray Industries, Inc.) colored layer Resin: Polyester resin (Vylon 200, manufactured by Toyobo Co., Ltd.) Isocyanate: Aliphatic Isocyanate HDI Pigment: Carbon black Solvent: "Toluene:MEK=1:1" Formula: Resin: Isocyanate: Pigment: Solvent = 20:3:15:62 adhesive layer Acrylic adhesive a

[0051] The gel fraction of the adhesive layer obtained from the acrylic adhesive a was measured using the method of formula (1) above and was found to be 35%. The glass transition temperature (Tg) was measured using the following method and was found to be 3°C. The glass transition temperature (Tg) of the adhesive layer obtained from acrylic adhesive a was determined by measuring the storage modulus G' and loss modulus G" at each temperature using a polymer dynamic viscoelasticity measuring device "itkDVA-200" (manufactured by IT Measurement Control Co., Ltd.) under the conditions below, calculating tan δ at each temperature, and determining the temperature at which tan δ reached its peak value as Tg. Measurement mode: Shear Heating rate: 5°C / min Measurement temperature range: -30 to 150°C Setting distortion: 0.1% Frequency: 1Hz

[0052] The measurement sample was prepared by heating, drying, and aging acrylic adhesive a under the same conditions as when forming the adhesive layer, and then molding the final sample shape to a thickness of 1 mm, width of 6 mm, and length of 10 mm. Release film Silicone release-treated PET film (SP3000, manufactured by Toyo Cross Co., Ltd.)

[0053] Example 2 A colored adhesive tape was obtained in the same manner as in Example 1, except that the paint for forming the colored layer was different from that in Example 1. The materials for the paint for forming the colored layer in Example 2 are as follows. colored layer Resin: Polyester resin (Vylon 200, manufactured by Toyobo Co., Ltd.) Isocyanate: Aliphatic Isocyanate HDI Pigment: 15 parts carbon black, 1 part phthalocyanine blue Solvent: "Toluene:MEK=1:1" Formula: Resin: Isocyanate: Pigment: Solvent = 20:3:16:62

[0054] Example 3 A colored adhesive tape was obtained in the same manner as in Example 1, except that the paint for forming the colored layer was different from that in Example 1. The materials for the paint for forming the colored layer in Example 3 are as follows. colored layer Resin: Acrylic resin Isocyanate: Aliphatic Isocyanate HDI Pigment: Carbon black Solvent: "Toluene:MEK=1:1" Formula: Resin: Isocyanate: Pigment: Solvent = 20:3:16:62

[0055] Example 4 A colored adhesive tape was obtained in the same manner as in Example 1, except that the material of the paint for forming the matte layer was different from that in Example 1. The material of the paint for forming the matte layer in Example 4 is as follows. Matte layer Resin: Polyester resin (Vylon 200, manufactured by Toyobo Co., Ltd.) Isocyanate: Aliphatic Isocyanate HDI Matting agent: Silica (Silo Hobic 100, manufactured by Fuji Silysia Chemical Co., Ltd.) Pigment: Carbon black Solvent: "Toluene:MEK=1:1" Formula: Resin: Isocyanate: Matting agent: Solvent: Pigment = 20:3:5:72:1

[0056] Example 5 A colored adhesive tape was obtained in the same manner as in Example 1, except that the amount of paint for forming the matte layer was different from that in Example 1. In Example 5, the matte layer was formed by the following procedure. A matte layer was applied to the other side of the resin film layer, which had a colored layer formed on one side, using a bar coater. The wire bar used was #8. After application, the coating was dried in an oven at 80°C for 2 minutes and then aged in an oven at 40°C for 1 day to form a matte layer. The thickness of the matte layer after aging was 3.0 μm.

[0057] Example 6 A colored adhesive tape was obtained in the same manner as in Example 1, except that the amount of paint for forming the matte layer was different from that in Example 1. In Example 6, the matte layer was formed by the following procedure. A matte layer was applied to the other side of the resin film layer, which had a colored layer formed on one side, using a bar coater. The wire bar used was #3. After application, the coating was dried in an 80°C oven for 2 minutes and then aged in a 40°C oven for 1 day to form a matte layer. The matte layer thickness after aging was 0.5 μm.

[0058] Examples 7 to 12 A colored adhesive tape was obtained in the same manner as in Example 1, except that the adhesive for forming the adhesive layer was different. In Examples 7 to 12, the adhesives shown in Table 1-2 were used as the adhesive for forming the adhesive layer. That is, in Examples 7 to 12, acrylic adhesives b to g were used as the adhesive for forming the adhesive layer, respectively. These acrylic adhesives b to g were each produced by the following procedure.

[0059] (1-1) Preparation of Acrylic Copolymer B (Solution Polymerization) Ethyl acetate was added to the reaction vessel as a polymerization solvent, and after bubbling with nitrogen, the reaction vessel was heated while nitrogen was flowing in to initiate reflux. Next, a polymerization initiator solution prepared by diluting 0.1 parts by weight of azobisisobutyronitrile 10 times with ethyl acetate was added to the reaction vessel, and 96.6 parts by weight of n-heptyl acrylate, 2.9 parts by weight of acrylic acid, and 0.5 parts by weight of 2-hydroxyethyl acrylate were added dropwise over 2 hours. After the dropwise addition was completed, a polymerization initiator solution prepared by diluting 0.1 parts by weight of azobisisobutyronitrile 10 times with ethyl acetate was added again to the reaction vessel, and the polymerization reaction was carried out for 4 hours to obtain a solution containing acrylic copolymer B.

[0060] The obtained acrylic copolymer B-containing solution was diluted 50 times with tetrahydrofuran (THF), and the resulting diluted solution was filtered through a filter (material: polytetrafluoroethylene, pore size: 0.2 μm) to prepare a measurement sample. This measurement sample was supplied to a gel permeation chromatograph (Waters, 2690 Separations Model) and subjected to GPC measurement under conditions of a sample flow rate of 1 mL / min and a column temperature of 40°C. The polystyrene-equivalent molecular weight of acrylic copolymer B was measured, and the weight-average molecular weight was found to be 1,000,000.

[0061] To the obtained acrylic copolymer B-containing solution, 14 parts by weight of polymerized rosin ester (hydroxyl value: 46, softening point: 152°C) as a tackifying resin, 10 parts by weight of hydrogenated rosin ester (KE359, manufactured by Arakawa Chemical Industries, Ltd.), 10 parts by weight of terpene phenol (G150, manufactured by Yasuhara Chemical Co., Ltd.), and 0.5 parts by weight of an isocyanate-based crosslinking agent (Takenate D-101E, manufactured by Mitsui Chemicals, Inc.) were added per 100 parts by weight of acrylic copolymer B to obtain an acrylic adhesive (hereinafter referred to as acrylic adhesive b). The gel fraction of the adhesive layer obtained from the acrylic adhesive b was measured using the method of formula (1) above and was found to be 35%. The glass transition temperature (Tg) of the adhesive layer was measured using the same method as in Example 1 and was found to be -8°C.

[0062] (1-2) Preparation of acrylic copolymer C (solution polymerization) Ethyl acetate was added to the reaction vessel as a polymerization solvent, and after bubbling with nitrogen, the reaction vessel was heated while nitrogen was flowing in to initiate reflux. Subsequently, a polymerization initiator solution prepared by diluting 0.1 parts by weight of azobisisobutyronitrile 10 times with ethyl acetate was added to the reaction vessel, and 95.1 parts by weight of n-heptyl acrylate, 4.8 parts by weight of acrylic acid, and 0.1 parts by weight of 2-hydroxyethyl acrylate were added dropwise over 2 hours. After the dropwise addition, a polymerization initiator solution prepared by diluting 0.1 parts by weight of azobisisobutyronitrile 10 times with ethyl acetate was added again to the reaction vessel, and the polymerization reaction was carried out for 4 hours to obtain a solution containing acrylic copolymer C.

[0063] The obtained acrylic copolymer C-containing solution was diluted 50 times with tetrahydrofuran (THF), and the resulting diluted solution was filtered through a filter (material: polytetrafluoroethylene, pore size: 0.2 μm) to prepare a measurement sample. This measurement sample was supplied to a gel permeation chromatograph (Waters, 2690 Separations Model) and subjected to GPC measurement under conditions of a sample flow rate of 1 mL / min and a column temperature of 40°C. The polystyrene-equivalent molecular weight of acrylic copolymer C was measured, and the weight-average molecular weight was found to be 1,200,000.

[0064] To the obtained acrylic copolymer C-containing solution, 14 parts by weight of polymerized rosin ester (hydroxyl value: 46, softening point: 152°C) as a tackifying resin, 10 parts by weight of hydrogenated rosin ester (KE359, manufactured by Arakawa Chemical Industries, Ltd.), 10 parts by weight of terpene phenol (G150, manufactured by Yasuhara Chemical Co., Ltd.), and 2.5 parts by weight of an isocyanate-based crosslinking agent (Takenate D-101E, manufactured by Mitsui Chemicals, Inc.) were added per 100 parts by weight of acrylic copolymer C to obtain an acrylic adhesive (hereinafter referred to as acrylic adhesive c). The gel fraction of the adhesive layer obtained from acrylic adhesive c was measured using the method using the above formula (1) and was found to be 35%. The glass transition temperature (Tg) of the adhesive layer was measured using the same method as in Example 1 and was found to be -1°C.

[0065] To the obtained acrylic copolymer C-containing solution, 24 parts by weight of polymerized rosin ester (hydroxyl value: 46, softening point: 152°C) as a tackifying resin, 10 parts by weight of terpene phenol (Yasuhara Chemical Co., Ltd., G150), and 2.5 parts by weight of an isocyanate-based crosslinking agent (Mitsui Chemicals, Inc., Takenate D-101E) were added per 100 parts by weight of acrylic copolymer C to obtain an acrylic adhesive (hereinafter referred to as acrylic adhesive d). The gel fraction of the adhesive layer obtained from acrylic adhesive d was measured using the method of formula (1) above and was found to be 30%. The glass transition temperature (Tg) of the adhesive layer was measured using the same method as in Example 1 and was found to be 0°C.

[0066] To the obtained acrylic copolymer C-containing solution, 14 parts by weight of polymerized rosin ester (hydroxyl value: 46, softening point: 152°C) as a tackifying resin, 10 parts by weight of hydrogenated rosin ester (KE359, manufactured by Arakawa Chemical Industries, Ltd.), 10 parts by weight of terpene phenol (G150, manufactured by Yasuhara Chemical Co., Ltd.), and an epoxy-based crosslinking agent (A-EX, solids content 5%, manufactured by Soken Chemical & Engineering Co., Ltd.) were added so that the solids content was 0.1 parts by weight per 100 parts by weight of acrylic copolymer C, thereby obtaining an acrylic adhesive (hereinafter referred to as acrylic adhesive e). The gel fraction of the adhesive layer obtained from the acrylic adhesive e was measured using the method using the above formula (1) and was found to be 55%. The glass transition temperature (Tg) of the adhesive layer was measured using the same method as in Example 1 and was found to be 1°C.

[0067] To the obtained acrylic copolymer C-containing solution, 14 parts by weight of polymerized rosin ester (hydroxyl value: 46, softening point: 152°C) as a tackifying resin, 10 parts by weight of hydrogenated rosin ester (KE359, manufactured by Arakawa Chemical Industries, Ltd.), 10 parts by weight of terpene phenol (G150, manufactured by Yasuhara Chemical Co., Ltd.), 1.2 parts by weight of an isocyanate-based crosslinking agent (Takenate D-101E, manufactured by Mitsui Chemicals, Inc.), and 0.05 parts by weight of an epoxy-based crosslinking agent (A-EX solids content 5% manufactured by Soken Chemical & Engineering Co., Ltd.) were added per 100 parts by weight of acrylic copolymer C, to obtain an acrylic adhesive (hereinafter referred to as acrylic adhesive f). The gel fraction of the adhesive layer obtained from the acrylic adhesive f was measured using the method using the above formula (1) and was found to be 65%. The glass transition temperature (Tg) of the adhesive layer was measured using the same method as in Example 1 and was found to be 2°C.

[0068] To the obtained acrylic copolymer C-containing solution, 14 parts by weight of polymerized rosin ester (hydroxyl value: 46, softening point: 152°C) as a tackifying resin, 10 parts by weight of hydrogenated rosin ester (KE359, manufactured by Arakawa Chemical Industries, Ltd.), 10 parts by weight of terpene phenol (G150, manufactured by Yasuhara Chemical Co., Ltd.), 2.5 parts by weight of an isocyanate-based crosslinking agent (Takenate D-101E, manufactured by Mitsui Chemicals, Inc.), and a pigment (Multilac A903, solids content 55%, manufactured by Dainichiseika Color & Chemicals Mfg. Co., Ltd.) were added so that the solids content was 1 part by weight, relative to 100 parts by weight of acrylic copolymer C, to obtain an acrylic adhesive (hereinafter referred to as acrylic adhesive g). The gel fraction of the adhesive layer obtained from the acrylic adhesive g was measured using the method of formula (1) above and was found to be 35%. The glass transition temperature (Tg) of the adhesive layer was measured using the same method as in Example 1 and was found to be -1°C.

[0069] (Comparative Example 1) A colored adhesive tape was produced in the same manner as in Example 1, except that the amount of paint for forming the matte layer was different from that in Example 1. In Comparative Example 1, the matte layer was formed by the following procedure. The resin film layer had a colored layer formed on one side, and the other side was coated with the following matte layer-forming paint using a bar coater. The wire bar used was #3. After coating, the coating was dried in an 80°C oven for 2 minutes and then aged in a 40°C oven for 1 day to form a matte layer. The matte layer thickness after aging was 0.3 μm. Matte layer Resin: Polyester resin (Vylon 200, manufactured by Toyobo Co., Ltd.) Isocyanate: Aliphatic Isocyanate HDI Matting agent: Silica (Silo Hobic 100, manufactured by Fuji Silysia Chemical Co., Ltd.) Pigment: None Solvent: "Toluene:MEK=1:1" Formula: Resin: Isocyanate: Matting agent: Solvent: Pigment = 20:3:5:90:0

[0070] (Comparative Example 2) A colored adhesive tape was produced in the same manner as in Example 1, except that the lamination order of the colored layer and the resin film layer was different from that in Example 1. In Comparative Example 2, a colored adhesive tape was produced by the following procedure. A PET film was prepared as the resin film layer, and the paint for forming the colored layer was applied to one side of the resin film layer using a bar coater. The wire bar used was #8. After application, the coating was dried in an oven at 80°C for 2 minutes to form a colored layer. The thickness of the colored layer after drying was 2.5 μm.

[0071] Next, a matte layer coating was applied onto the colored layer using a bar coater. The wire bar used was #5. After coating, the coating was dried in an oven at 80°C for 2 minutes, and then aged in an oven at 40°C for 1 day to form a matte layer. The thickness of the matte layer after aging was 1.5 μm. Next, a 38 μm thick PET film with a silicone release-treated surface was prepared as a release film, and an acrylic adhesive was applied to the silicone release-treated surface of the release film using an applicator. After application, the film was dried in an oven at 110°C for 2 minutes to form an adhesive layer. The adhesive layer was 2 μm thick. Next, the colored layer side of the resin film layer and the adhesive layer side of the release film were placed facing each other, and the two were laminated together with a roller, followed by aging for 2 days in an oven at 40° C. This produced a colored adhesive tape consisting of a laminate of "matte layer / colored layer / resin film layer / adhesive layer / release film."

[0072] (Comparative Example 3) A colored adhesive tape was produced in the same manner as in Example 1, except that the matte layer was not provided. In Comparative Example 3, a colored adhesive tape was produced by the following procedure. A PET film was prepared as the resin film layer, and the paint for forming the colored layer was applied to one side of the resin film layer using a bar coater. The wire bar used was #8. After application, the coating was dried in an oven at 80°C for 2 minutes to form a colored layer. The thickness of the colored layer after drying was 2.5 μm.

[0073] Next, a 38 μm thick PET film with a silicone release-treated surface was prepared as a release film, and the adhesive layer was applied to the silicone release-treated surface of the release film using an applicator. After application, the coating was dried in an oven at 110°C for 2 minutes to form an adhesive layer. The adhesive layer had a thickness of 2 μm. Next, the colored layer side of the resin film layer and the adhesive layer side of the release film were placed opposite each other and laminated together with a roller, and then aged for 2 days in an oven at 40° C. This produced a colored adhesive tape consisting of a laminate of "resin film layer / colored layer / adhesive layer / release film."

[0074] (Evaluation method) The colored pressure-sensitive adhesive tapes for evaluation of Examples 1 to 12 and Comparative Examples 1 to 3 were evaluated for total film thickness, transmittance, gloss value, surface property, and hue. (total film thickness) The thickness of the entire colored adhesive tape was measured as the total film thickness. The total film thickness was evaluated as ◯ when it was 5 μm or more and less than 10 μm, and x when it was outside this range.

[0075] (transmittance) The light transmittance (total light transmittance) of the laminate excluding the release film of each colored adhesive tape was measured in accordance with JIS K7105 using an HR-100 made by Murakami Color Research Laboratory. A light transmittance of 5% or less was evaluated as ◯, and a light transmittance of more than 5% was evaluated as x. (gross value) The gloss value of the surface of the matte layer side of the colored adhesive tape was measured using a commercially available gloss meter (for example, the "High Gloss Gloss Checker IG-410" manufactured by Horiba, Ltd.) at a measurement angle of 60°. A gloss value of 3.0 or less at a measurement angle of 60° was evaluated as ◯, and a gloss value of more than 3.0 was evaluated as ×.

[0076] (face) The surface of the colored adhesive tape, which is the side opposite to the release film of the colored adhesive tape, was visually observed to evaluate the surface properties of the colored adhesive tape. The surface of the colored adhesive tape was evaluated for uniformity and the absence of unevenness. The colored adhesive tape was rated as ◯ when the surface was uniform, and as x when it was not uniform or had unevenness. (hue) The hue of the surface of the colored adhesive tape was visually observed, and the difference in hue from the colored adhesive tape of Example 1 was observed.

[0077] [Table 3]

[0078] As shown in Table 3, the colored adhesive tapes of Examples 1 to 12, which had a configuration in which a matte layer, a resin film layer, a colored layer, an adhesive layer, and a release film were laminated in this order from the release film side, and in which the matte layer thickness was 0.5 μm or more and 3 μm or less, had a light transmittance of 2.5% and a 60° gloss value of 1.5 for Examples 1 to 4 and Examples 7 to 12, 0.9 for Example 5, and 2.9 for Example 6, confirming that they had good color, texture, and matte feel, and a uniform, even surface. Furthermore, as shown in Examples 7 to 12, even when the components constituting the adhesive layer were different, they were confirmed to have good color, texture, and matte feel, and a uniform, even surface.

[0079] Furthermore, the colored adhesive tape of Example 2 uses not only carbon black but also phthalocyanine blue as the pigment in the colored layer, and therefore the resulting colored adhesive tape has an increased blueness. Furthermore, even in the case of Example 3, in which an acrylic resin is used instead of a polyester resin for the colored layer, it was confirmed that the same effect as in Example 1, in which a polyester resin was used, can be obtained. Further improvement in blocking properties can be expected when an acrylic resin is used. Furthermore, in Example 4, in which carbon black is added as a pigment to the matte layer, it was confirmed that the colored adhesive sheet of Example 1, in which no pigment is added to the matte layer, has an increased blackness.

[0080] In Comparative Example 1, where the matte layer was 0.3 μm thick, the 60° gloss value was large, making it difficult to obtain a matte finish, and the inspection light source used for defect inspection was reflected by the surface of the matte layer, making it difficult to find defects.On the other hand, in Example 5, where the matte layer was 3.0 μm thick, a sufficient matte finish was obtained. In addition, the colored adhesive tape of Comparative Example 2, in which a matte layer was laminated directly on top of a colored layer, had a rough surface of the colored layer in contact with the matte layer due to the influence of the solvent in the matte layer, resulting in a lot of unevenness on the surface of the colored adhesive tape opposite the release film, i.e., the surface on the matte layer side, and reduced design appeal.

[0081] Furthermore, the colored adhesive tape of Comparative Example 3, which does not have a matte layer, has a gloss value of 113, which does not achieve a matte finish, and the inspection light source used for defect inspection is reflected by the surface of the resin film layer, making it even more difficult to find defects than Comparative Example 1. For Examples 1 to 4, the water contact angle was measured in accordance with JIS R 3257:1999 and was found to be 105°, confirming that the antifouling properties were sufficiently high.

[0082] The present invention can have the following configurations, for example. (1) A colored adhesive tape having a release film, an adhesive layer, a colored layer, a resin film layer, and a matte layer laminated in this order, the matte layer is a layer containing a polyester resin, an isocyanate, and a matte agent as main components, the matte agent containing silica, and having a thickness of 0.5 μm or more and 3 μm or less; The colored adhesive tape is characterized in that the colored layer is a layer containing a resin, an isocyanate, and a pigment containing carbon black as main components. (2) The colored adhesive tape according to (1) above, wherein the light transmittance of a laminate of the adhesive layer, the colored layer, the resin film layer, and the matte layer is 5% or less. (3) The colored adhesive tape according to (1) or (2) above, wherein the 60° gloss value of the surface on the matte layer side is 3 or less. (4) The colored adhesive tape according to any one of (1) to (3) above, wherein the matte layer is colored. (5) The colored adhesive tape according to any one of (1) to (4) above, which is used for protecting the surface of a heat dissipation sheet. (6) The colored adhesive tape according to any one of (1) to (4) above, which is used for protecting the surface of a magnetic sheet. [Explanation of symbols]

[0083] 1 colored adhesive tape 2 Matte layer 3 Resin film layer 4 Colored layer 5 Adhesive layer 6 Release film 10 Heat dissipation sheet or magnetic sheet

Claims

1. A colored adhesive tape having a release film, an adhesive layer, a colored layer, a resin film layer, and a matte layer laminated in this order, a matte layer is formed in direct contact with one surface of the resin film layer, and a colored layer is formed in direct contact with the other surface of the resin film layer; the matte layer is a layer containing a polyester resin, an isocyanate, and a matte agent as main components, the matte agent containing silica, and having a thickness of 0.5 μm or more and 3 μm or less; The colored layer is a layer containing a resin, an isocyanate, and a pigment containing carbon black as its main components (excluding those containing silica particles). A colored adhesive tape characterized by:

2. 2. The colored adhesive tape according to claim 1, wherein the light transmittance of a laminate of the adhesive layer, the colored layer, the resin film layer, and the matte layer is 5% or less.

3. 3. The colored adhesive tape according to claim 1, wherein the 60° gloss value of the surface on the matte layer side is 3 or less.

4. 3. The colored adhesive tape according to claim 1, wherein the matte layer is colored.

5. 3. The colored adhesive tape according to claim 1, which is used for protecting the surface of a heat dissipation sheet.

6. 3. The colored adhesive tape according to claim 1, which is used for protecting the surface of a magnetic sheet.

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