Colored film and colored adhesive tape

Abstract

The present invention provides a colored film which is thin, and has excellent alcohol resistance, curl resistance, and interlayer adhesion, and a colored adhesive tape having the colored film. The present invention provides a colored film having a resin film layer and a colored layer provided on one side of the resin film layer, the thickness of the resin film layer being in the range of 1 μm to 12 μm, the colored layer containing a resin cured product and a coloring material, and the glass transition temperature being in the range of 45°C to 65°C, the thickness of the colored layer being in the range of 1 μm to 4 μm.

Description

Technical Field

[0001] The present invention relates to a thin colored film and a colored pressure-sensitive adhesive tape for components used to protect circuits of electronic devices such as mobile phones and electronic organizers. Background Art

[0002] As a joining method with excellent workability and high adhesion reliability, adhesive tapes are used for fixing and protecting components in various industrial fields such as OA equipment and household electrical appliances. While these OA devices achieve various higher functionalities, miniaturization and thinning are also pursued. In electronic terminals such as personal computers, digital video cameras, electronic organizers, mobile phones, smart phones, game consoles and e-books, thinning of main components is required, and thinning of adhesive tapes used for these protection purposes is also required.

[0003] In addition, in order for these adhesive tapes to protect components and improve the shielding of appearance defects (unevenness, point defects, etc.) and the overall appearance of the components, there is a demand for very thin colored adhesive tapes (colored adhesive tapes) with a thickness of 20 µm or less that include a colored film. Furthermore, in the process of bonding these adhesive tapes to electronic components, wiping with alcohol is sometimes performed to remove foreign matter generated during processing. To avoid appearance defects caused by such wiping, the colored layer of the colored film is required to have alcohol resistance.

[0004] To improve the alcohol resistance of the colored layer, it is common practice to increase the hardness of the resin in the colored layer (Patent Document 1). However, when a resin with high hardness is printed on a film substrate, problems such as curling of the colored film and peeling due to low adhesion between the colored layer and the substrate film occur. Therefore, in thin colored films and colored adhesive tapes including such colored films, there is a problem that it is difficult to achieve improved alcohol resistance, curling resistance and interlayer adhesion of the colored film at the same time.

[0005] Patent Document 1: Japanese Patent Application Laid-Open No. 2012-92281 Summary of Invention

[0006] The problem to be solved by the present invention is to provide a thin colored film excellent in alcohol resistance, curling resistance and interlayer adhesion, and a colored adhesive tape including the colored film.

[0007] The inventors of the present invention conducted intensive studies to achieve the above object, and found that the object of the present invention can be achieved by a colored film having a resin film layer with a specific thickness and a colored layer with a specific thickness and glass transition temperature, and a colored adhesive tape provided with an adhesive layer on the colored film, thus completing the present invention.

[0008] That is, the present invention provides a coloring film having a resin film layer and a coloring layer disposed on one side of the resin film layer, wherein the thickness of the resin film layer is in the range of 1 μm to 12 μm, the coloring layer comprises a resin curing agent and a coloring material, and the glass transition temperature is in the range of 45°C to 65°C, and the thickness of the coloring layer is in the range of 1 μm to 4 μm. In addition, the present invention provides a colored adhesive tape having the above-described colored film and an adhesive layer disposed on the surface of the colored film on the side of the resin film layer of the colored film, wherein the total thickness of the colored adhesive tape is 20 μm or less.

[0009] The coloring film and the coloring adhesive tape containing the coloring film of the present invention are extremely thin and exhibit good alcohol resistance. Furthermore, they can appropriately suppress curling and interlayer delamination within the coloring film. Therefore, the coloring film and the coloring adhesive tape of the present invention are suitable for protecting circuit components in portable electronic devices that require miniaturization, thinness, and high alcohol resistance. Attached Figure Description

[0010] Figure 1 This is a schematic cross-sectional view showing an example of the coloring film of the present invention. Figure 2 This is a schematic cross-sectional view showing an example of the colored adhesive tape of the present invention. Detailed Implementation

[0011] I. Colored film The coloring film of the present invention has a resin film layer and a coloring layer disposed on one side of the resin film layer. The thickness of the resin film layer is in the range of 1 μm to 12 μm. The coloring layer comprises a resin curing agent and a coloring material, and has a glass transition temperature in the range of 45°C to 65°C. The thickness of the coloring layer is in the range of 1 μm to 4 μm.

[0012] Figure 1 This is a schematic cross-sectional view illustrating an example of the coloring film of the present invention. For example... Figure 1 As illustrated, the coloring film 10 of the present invention has a resin film layer 1 and a coloring layer 2 disposed on one side of the resin film layer 1. In the coloring film 10 of the present invention, the thickness of the resin film layer 1 is in the range of 1 μm to 12 μm. Furthermore, the coloring layer 2 is a layer comprising a cured resin and a coloring material, the glass transition temperature of the coloring layer 2 is in the range of 45°C to 65°C, and the thickness is in the range of 1 μm to 4 μm.

[0013] According to the present invention, by forming a colored layer with a glass transition temperature within a specified range on one side of a resin film layer having a specified thickness, an extremely thin structure can be formed, and it has good alcohol resistance, curl resistance and interlayer adhesion.

[0014] 1. Resin film layer The resin film layer used in the coloring film of the present invention only needs to be a resin film layer with a thickness of 1 to 12 μm, more preferably 1.5 to 6 μm, and even more preferably 2 to 4.5 μm. By setting the thickness to 1 μm or more, suitable curl resistance and adhesion can be easily achieved, and by setting it to 12 μm or less, suitable thinness can be achieved.

[0015] As the resin film constituting the resin film layer, various resin films used as substrates for adhesive tapes can be used, for example. Among these, resin films with a tensile strength of 1.5 N / 10 mm to 15 N / 10 mm are preferred because they are not easily cut even in extremely thin configurations. A more preferred tensile strength for the resin film is 2.5 N / 10 mm to 15 N / 10 mm. It should be noted that the tensile strength is a value obtained by tensile testing according to JIS Z0237-2000 at a tensile speed of 300 mm / min.

[0016] The resin film used in the resin film layer can contain various coloring pigments, but in order to impart concealment to the colored film and achieve suitable inspection, a transparent resin film without coloring pigments is preferred. Furthermore, by using a transparent film without coloring pigments, high strength can be easily achieved even in extremely thin structures.

[0017] The resin membrane constituting the resin film layer is not particularly limited, and common resin membranes can be cited. Specifically, examples include polyester membranes, polyurethane membranes, polyethylene membranes, polypropylene membranes, cellulose membranes such as triacetyl cellulose, polyvinyl chloride membranes, polyvinylidene chloride membranes, polyvinyl alcohol membranes, ethylene-vinyl acetate copolymer membranes, polystyrene membranes, polycarbonate membranes, acrylic resin membranes, norbornene resin membranes, cyclic olefin resin membranes, and laminates of two or more of these. The resin membrane can be uniaxially stretched or biaxially stretched. From the perspective of good dimensional stability and strength within the aforementioned thickness range, polyester film is preferred. Various polyester films can be used as the polyester film; specifically, films obtained by homopolymerization or copolymerization of polyester resins such as polyethylene terephthalate (PET), polyethylene naphthalate (PEN), and polybutylene terephthalate (PBT) can be used. From the viewpoint of dimensional stability and strength, biaxially stretched polyester film is preferred. Among these, biaxially stretched PET film is preferred.

[0018] The following describes the manufacturing method of the resin film using polyester film as an example. A polyester sheet (polyester component) dried or undried by a known method, along with a lubricating material, coloring pigment, or a masterbatch containing a high concentration of coloring pigment, is fed into a compounding extruder and heated to a temperature above the melting point of the polyester component to melt it. Next, the molten polyester is extruded from a die and rapidly cooled and solidified on a rotary cooling drum to a temperature below the glass transition temperature, resulting in a substantially amorphous, unoriented sheet. In this case, to improve the flatness of the sheet, it is preferable to improve the adhesion between the sheet and the rotary cooling drum; electrostatic application and / or liquid coating methods are preferred. In the melt extrusion process, the following methods may also be used: shortening the residence time of the polyester in the extruder; in the case of using a single-spindle extruder, pre-drying the raw material to a moisture content of 50 ppm or less, preferably 30 ppm or less; in the case of using a twin-spindle extruder, providing an exhaust port and maintaining a pressure reduction of 40 hPa or less, preferably 30 hPa or less, and even more preferably 20 hPa or less.

[0019] The resulting sheet is stretched biaxially to form a film. Specifically, the stretching conditions are described below: the unstretched sheet is preferably stretched longitudinally at 70–145°C to 2–6 times its original length to form a longitudinally uniaxially stretched film, and then stretched transversely at 90–160°C to 2–6 times its original length before being transferred to a heat-setting process. Furthermore, it is preferable to relax the film longitudinally and / or transversely by 0.1–20% in the highest temperature zone of the heat treatment and / or the cooling zone at the heat treatment exit. Additionally, further longitudinal and transverse stretching may be performed as needed.

[0020] As long as the resin film layer is within the above-mentioned thickness range, it can have any shape in either a single layer or a laminate, without being restricted by structure.

[0021] To improve adhesion to coloring layers, adhesive layers, etc. formed on the surface of the resin film, the surface of the resin film can be subjected to conventional surface treatments, such as oxidation treatment using chemical or physical methods like chromic acid treatment, ozone exposure, flame exposure, high voltage electric shock exposure, or ionized radiation treatment, or coating treatment using a primer.

[0022] 2. Coloring layer The coloring layer in the coloring film of the present invention comprises a cured resin and a coloring material, and the glass transition temperature and thickness are respectively within a specified range. The coloring layer is disposed on one side of the resin film layer and is configured to be in direct contact with the surface of the resin film layer.

[0023] (1)Physical properties The glass transition temperature of the coloring layer in this invention is in the range of 45°C to 65°C. By keeping the glass transition temperature of the coloring layer within the above-specified range, when forming an extremely thin adhesive tape, it is less prone to curling even when coated on a thin resin film layer, and it adheres firmly to thin resin films that are difficult to bond with corona treatment or other similar processes. Furthermore, it achieves good alcohol resistance. From the viewpoint of balancing alcohol resistance and curl resistance, the glass transition temperature of the coloring layer is more preferably 48°C to 62°C, and particularly preferably 50°C to 60°C. The glass transition temperature is a value measured using DSC according to ISO 3146. The glass transition temperature of the coloring layer greatly influences the glass transition temperature of the cured resin in the coloring layer, and therefore can be adjusted primarily by the glass transition temperature of the cured resin.

[0024] Furthermore, the thickness of the coloring layer in this invention can be 1 to 4 μm, preferably 1.5 to 3.5 μm, and more preferably 2.0 to 3.0 μm. By making the thickness 1 μm or more, suitable design and adhesion to the resin film layer can be achieved; on the other hand, by making the thickness 4 μm or less, suitable thinness and curl resistance can be achieved.

[0025] The pencil hardness of the coloring layer is preferably HB to 2H. More preferably, it is F to H. Setting it to HB or higher achieves suitable alcohol resistance, while setting it to 2H or lower achieves suitable resistance to curling and adhesion to the resin film. The hardness of the coloring layer can be determined based on the scratch hardness (pencil method) according to JIS K5600.

[0026] (2) Composition The coloring layer comprises a cured resin and a coloring material. For example, the coloring layer can be formed by coating a coloring ink comprising a two-component curable resin and a coloring material onto one side of a resin film and allowing it to dry, wherein the two-component curable resin comprises a main agent and a curing agent. The coloring layer is a layer formed by the cured product of the coloring ink composition, and the cured product of the two-component curable resin comprising the main agent and the curing agent corresponds to the cured resin in the coloring layer.

[0027] <Cureable Resin> The resin curing agent included in the aforementioned coloring layer can be any resin capable of setting the glass transition temperature of the coloring layer within a specified range. The glass transition temperature of the resin curing agent can be 45–65°C, more preferably 48–62°C, and particularly preferably 50°C–60°C. The glass transition temperature of the resin curing agent is a value obtained by DSC measurement according to ISO 3146.

[0028] As for the cured resin, there are no particular limitations as long as the glass transition temperature falls within the aforementioned range; general-purpose resins can be used, such as cured polyester resins. The cured resin is a cured resin composition comprising a polyol component primarily composed of polyester polyol and an isocyanate component primarily composed of polyfunctional isocyanate (cured polyester resin). This is because by combining a coloring layer of a specified thickness and a resin film layer of a specified thickness, good alcohol resistance, curl resistance, and interlayer adhesion can be achieved, especially good adhesion to polyester resin films. It should be noted that "main component" refers to the component with the highest content among the contained components. For example, "polyol component primarily composed of polyester polyol" means that the polyester polyol content is the highest among the polyol components. The same applies to "isocyanate component primarily composed of polyfunctional isocyanate." The cured resin is a reaction cured product of the polyol component and the isocyanate component, preferably a cured polyester resin where the polyol component is polyester polyol and the isocyanate component is polyfunctional isocyanate. The glass transition temperature of the cured resin can be achieved by appropriately combining the polyol and isocyanate components in the correct ratio.

[0029] When the resin curing product of the coloring layer is a cured resin composition containing a polyol component mainly composed of polyester polyol and an isocyanate component mainly composed of polyfunctional isocyanate, the coloring layer can be formed using a coloring ink containing a two-component curing resin and a coloring material. The two-component curing resin contains the following main agent and curing agent: the polyol component mainly composed of polyester polyol is used as the main agent, and the isocyanate component mainly composed of polyfunctional isocyanate is used as the curing agent.

[0030] <<Polyol Components>> When the coloring layer comprises a cured resin composition containing a polyol component mainly composed of polyester polyol and an isocyanate component mainly composed of polyfunctional isocyanate, the molecular weight of the polyester polyol component is not particularly limited, but the mass-average molecular weight is preferably in the range of 1,000 to 400,000. If the mass-average molecular weight of the polyester polyol is 1,000 or more, the printability, coating suitability, and alcohol resistance of the resulting cured resin are easily suitable; by setting it to 400,000 or less, drying properties and anti-blocking properties are easily improved. The mass-average molecular weight of the polyester polyol is further preferably in the range of 2,000 to 350,000, and more preferably in the range of 3,000 to 300,000.

[0031] The mass-average molecular weights mentioned above are based on standard polystyrene obtained by gel permeation chromatography (GPC). As for the determination conditions, a TSKgel GMHXL column [manufactured by Tosoh] was used, the column temperature was 40°C, the eluent was tetrahydrofuran, the flow rate was 1.0 mL / min, and TSK standard polystyrene was used as the standard.

[0032] Polyester polyols are compounds having two or more hydroxyl groups. Examples of polyester polyols include those obtained by reacting one or more polyacids with one or more polyols, those obtained by ring-opening polymerization of cyclic ester compounds such as ε-caprolactone, and those obtained by copolymerizing them.

[0033] The polyacids used in the preparation of polyester polyols can all be well-known raw materials. Examples of polyacids that can be used alone or in mixtures of two or more of the following polyacids include: succinic acid, adipic acid, azelaic acid, sebacic acid, dodecanedicarboxylic acid, maleic anhydride, fumaric acid, 1,3-cyclopentanedicarboxylic acid, 1,4-cyclohexanedicarboxylic acid, terephthalic acid, isophthalic acid, phthalic acid, 1,4-naphthalenedicarboxylic acid, 2,5-naphthalenedicarboxylic acid, 2,6-naphthalenedicarboxylic acid, biphenyl dicarboxylic acid, 1,2-bis(phenoxy)ethane-p,p'-dicarboxylic acid, and other dicarboxylic acids and their anhydrides or ester-forming derivatives; p-hydroxybenzoic acid, p-(2-hydroxyethoxy)benzoic acid and their ester-forming derivatives, dimer acids, etc. The aforementioned dimer acids refer to products obtained by the Diels-Alder type dimerization reaction of C18 unsaturated fatty acids such as oleic acid and linoleic acid. Commercially available products include those obtained by adding hydrogen to unsaturated bonds to saturate them, and various other substances. Representative examples are compounds composed of 0-5% by mass of C18 monocarboxylic acids, 70-98% by mass of C36 dimer acids, and 0-30% by mass of C54 trimeric acids.

[0034] As polyols used in the preparation of polyester polyols, known raw materials can be used. Specific examples of polyols include ethylene glycol, propylene glycol, 1,3-propanediol, 1,4-butanediol, 1,5-pentanediol, 3-methyl-10-pentanediol, 1,6-hexanediol, neopentanediol, methylpentanediol, dimethylbutanediol, butyl ethyl propylene glycol, diethylene glycol, triethylene glycol, tetraethylene glycol, dipropylene glycol, tripropylene glycol, dihydroxyethoxybenzene, 1,4-cyclohexanediol, 1,4-cyclohexanediol, triethylene glycol, polycaprolactone diol, dimer diol, bisphenol A, hydrogenated bisphenol A, and other diols; through proprolactone, butylrolactone, ε-hexylene... Polyesters obtained by ring-opening polymerization of cyclic ester compounds such as lactones, δ-valerolactone, and β-methyl-δ-valerolactone; and polyethers obtained by addition polymerization of one or more compounds with two active hydrogen atoms, such as ethylene glycol, diethylene glycol, triethylene glycol, propylene glycol, trimethylene ethylene glycol, 1,3-butanediol, 1,4-butanediol, 1,6-hexanediol, and neopentyl glycol, with one or more monomers such as ethylene oxide, propylene oxide, butane oxide, styrene oxide, epichlorohydrin, tetrahydrofuran, and cyclohexylene. These polyols can be used alone or in mixtures of two or more.

[0035] The polyol component only needs to contain polyester polyol as the main component. It can contain only polyester polyol. As long as the glass transition temperature of the coloring layer can be set within the specified range, it can contain one or more polyols other than polyester polyol.

[0036] <<Isocyanate Ingredients>> In the case where the coloring layer comprises a cured resin composition containing a polyol component mainly composed of polyester polyol and an isocyanate component mainly composed of polyfunctional isocyanate, the isocyanate component is a component that reacts with the aforementioned polyol component mainly composed of polyester polyol, and is mainly composed of polyfunctional isocyanate.

[0037] Polyfunctional isocyanates are any polyfunctional isocyanates having two or more isocyanate groups in one molecule; diisocyanates having two isocyanate groups are preferred. Examples of diisocyanates include aromatic diisocyanates (diphenylmethane diisocyanate, phenyl diisocyanate, tetramethylphenyl diisocyanate, benzylene diisocyanate, low molecular weight diols and prepolymers of the above aromatic diisocyanates, etc.) and aliphatic diisocyanates (1,6-hexamethylene diisocyanate, 2,2,4-trimethylhexamethylene diisocyanate, lysine diisocyanate, ethylene glycol, propylene glycol and other low molecular weight diols and aliphatic diisocyanates, etc.). Prepolymers of isocyanates, alicyclic diisocyanates (isophorone diisocyanate, hydrogenated 4,4'-diphenylmethane diisocyanate, methylcyclohexylene diisocyanate, isopropylidene dicyclohexyl-4,4'-diisocyanate, low molecular weight diols and prepolymers of the above alicyclic diisocyanates, etc.), and mixtures of two or more thereof, adducts of the above diisocyanates with polyols, and isocyanurate esters, biuret esters, and ureocarbamate esters of the above diisocyanates, etc. Among these, aliphatic or alicyclic diisocyanates, their adducts, isocyanurate esters, biuret esters, or ureocarbamate esters exhibit less curling due to curing shrinkage, making them suitable for use in films.

[0038] The isocyanate component can contain one or more polyfunctional isocyanates. In addition, the isocyanate component can contain polyfunctional isocyanates as the main component, and other isocyanates can also be contained as long as the glass transition temperature of the colored layer is within the specified range.

[0039] The glass transition temperature of the cured resin can be achieved by appropriately combining the polyol and isocyanate components in their respective proportions. The proportion of the polyol component (main agent), primarily composed of polyester polyol, to the isocyanate component (curing agent), primarily composed of polyfunctional isocyanate, can be appropriately set based on the hydroxyl value of the main component, the polyester polyol, and the number of isocyanate groups in the polyfunctional isocyanate. For example, it is preferable to combine the components in a ratio (hydroxyl / isocyanate group) of 1 / 0.5 to 1 / 10 (equivalent ratio), more preferably 1 / 0.6 to 1 / 5.

[0040] <<Other>> The content of the cured resin in the coloring layer can be adjusted appropriately according to the intended use, and is preferably 30-90% by mass, more preferably 40-80% by mass, and even more preferably 50-65% by mass. This is because it allows the glass transition temperature to be within a specified range, resulting in good alcohol resistance. It should be noted that the content in the coloring layer is synonymous with the content in the solid components of the coloring ink that forms the coloring layer. Furthermore, the cured resin in the coloring layer can be one type or can contain two or more types.

[0041] <Coloring Materials> As a coloring material, halogen-free, commonly used pigments and dyes can be used, and the appropriate selection can be made according to the color to be produced by the colored layer. For example, considering weather resistance, heat resistance, and dispersibility relative to ink resin, carbon black is preferred for black, titanium oxide, calcium carbonate, and barium sulfate are preferred for white, iron oxide yellow is preferred for yellow, iron oxide red is preferred for red, phthalocyanine blue is preferred for blue, aluminum powder is preferred for silver, and mica titanium powder is preferred for pearlescent. Among these, carbon black has excellent concealing properties and is therefore preferred.

[0042] The amount of coloring material added can be adjusted appropriately according to the application, etc., and is preferably 10 to 70% by mass in the coloring layer. More preferably, it is 20 to 60% by mass, and even more preferably, it is 35 to 50% by mass. If it is 10% by mass or more, good concealment can be achieved, and if it is 70% by mass or less, good dispersibility and adhesion to the resin film can be achieved. It should be noted that the content in the coloring layer is synonymous with the content in the solid components of the coloring ink that forms the coloring layer.

[0043] <Any Component> The coloring layer and the coloring ink forming the coloring layer may contain any materials. Examples of such materials include commonly used ink additives such as blocking agents and crosslinking accelerators such as dibutyltin.

[0044] Furthermore, the coloring layer may contain resins other than the aforementioned cured resin, provided that it does not impair the glass transition temperature or the effects of the present invention. Of the resins other than the coloring material contained in the coloring layer, the proportion of cured resin is preferably 90% by mass or more, more preferably 95% by mass or more, and particularly preferably substantially free of resins other than the aforementioned cured resin.

[0045] (3) Formation method A colored layer can be formed by printing a colored ink obtained by dissolving and dispersing the above-mentioned colored ink composition in an organic solvent using a desired printing method and then drying it. Examples of printing methods for the colored ink include known methods such as direct gravure printing, reverse gravure printing, and small-diameter gravure printing. Among these, direct gravure printing, which is preferred because it is less prone to damage even in thin resin films and has excellent printability, is preferred.

[0046] The organic solvent used to form the coloring layer of the coloring ink is not particularly limited, but an organic solvent without hydroxyl groups is preferred when dispersing the coloring material in the polyester polyol and for dilution. Known organic solvents can be used as non-hydroxyl-containing organic solvents. Examples include esters such as ethyl acetate, butyl acetate, and acetic acid solvent; ketones such as acetone, methyl ethyl ketone, isobutyl ketone, and cyclohexanone; ethers such as tetrahydrofuran and dioxane; aromatic hydrocarbons such as toluene and xylene; halogenated hydrocarbons such as dichloromethane and dichloroethane; dimethyl sulfoxide; and dimethyl sulfonamide. Ethyl acetate and methyl ethyl ketone are preferred.

[0047] 3. Arbitrary composition In addition to the aforementioned coloring layer and resin film layer, the coloring film of the present invention may also have a matte layer with a glass transition temperature within a specified range on the surface of the coloring layer. This matte layer is typically disposed in direct contact with the surface of the coloring layer without any other layers in between.

[0048] The glass transition temperature range of the matte layer can be set to be the same as the glass transition temperature range of the cured resin contained in the coloring layer. That is, the glass transition temperature of the matte layer can be 45 to 65°C, more preferably 48 to 62°C, and particularly preferably 50 to 60°C. By setting the glass transition temperature of the matte layer to the above range, even a coloring film with a matte layer can exhibit resistance to curling and alcohol.

[0049] The matte layer is a layer comprising a resin binder and microparticles. Examples of microparticles include commonly used microparticles such as silica, calcium carbonate, and barium sulfate. Furthermore, the glass transition temperature of the matte layer is primarily determined by the glass transition temperature of the resin binder; therefore, as the resin binder, a resin within the aforementioned specified glass transition temperature range can be appropriately selected from commonly used resins in matte layers. Preferably, the matte layer is a matte layer in which silica particles are dispersed in a urethane resin.

[0050] The thickness of the matte layer is not particularly limited as long as it achieves the desired function, but is preferably 0.3 μm or more, 0.4 μm or more, or 0.5 μm or more. Furthermore, the thickness of the matte layer is preferably 3 μm or less, 2 μm or less, or 1.5 μm or less. More specifically, the thickness of the matte layer is preferably 0.3 μm or more and 3 μm or less, and more preferably 0.5 μm or more and 1.5 μm or less.

[0051] The matte layer can be formed by coating a known surface treatment agent containing a matte agent (i.e., a matte agent) with microparticles dispersed in the resin binder onto the surface of the colored layer opposite to the resin film layer side.

[0052] 4. Colored film In the coloring film of the present invention, the combination of resin film layer and coloring layer is not particularly limited as long as the thickness of each layer and the glass transition temperature of the coloring layer are satisfied. Since the adhesion between the resin film layer and the coloring layer is improved, it is more preferable that the resin film layer is a polyester film and the coloring layer is a combination of layers containing a cured resin composition. The resin composition contains a polyol component with polyester polyol as the main component and an isocyanate component with polyfunctional isocyanate as the main component.

[0053] The coloring film of the present invention can have a coloring layer disposed on at least one side of the resin film layer, or it can have coloring layers disposed on both sides of the resin film layer. For example, a first coloring layer can be provided on a first side of the resin film layer, and a second coloring layer can be provided on a second side of the resin film layer opposite to the first side. The coloring layers disposed on one or both sides of the resin film layer are formed in a manner that is in direct contact with the surface of the resin film layer without being separated by other layers.

[0054] Furthermore, in the colored film layer, the colored layer disposed on one side of the resin film layer can be a single layer or a multilayer consisting of two or more layers formed by multicolor printing or the like. When colored layers are disposed on both sides of the resin film layer, the colored layer on each side can be a single layer or a multilayer. When the colored layer is a multilayer consisting of two or more layers, the layers constituting the colored layer are stacked in direct contact without any gaps between them. Furthermore, when the colored layer is a multilayer consisting of two or more layers, the composition of each layer constituting the colored layer can be the same or different, provided that each layer exhibits the aforementioned glass transition temperature. The cured resin contained in each layer preferably exhibits the aforementioned glass transition temperature.

[0055] The thickness of the coloring film of the present invention is preferably 2 to 16 μm, more preferably 3 to 9.5 μm, and particularly preferably 4 to 7.5 μm. By setting the thickness of the coloring film to 2 μm or more, suitable resistance to curling and wrinkle suppression and cutting resistance during application can be achieved, and by setting it to 16 μm or less, suitable thinness can be achieved.

[0056] The arithmetic mean roughness Ra of the surface of the colored layer side of the colored film of the present invention is preferably 0.20 to 0.60 μm, more preferably 0.25 to 0.55 μm, and even more preferably 0.30 to 0.45 μm. By setting the arithmetic mean roughness Ra of the surface of the colored layer side of the colored film to 0.2 μm or more, good anti-adhesion properties can be achieved, and by setting it to 0.6 μm or less, suitable adhesion to the resin film can be achieved. It should be noted that, in the colored film of the present invention, the layer constituting the outermost surface on one side is generally a colored layer or a matte layer formed on the surface of the colored layer. Therefore, the arithmetic mean roughness Ra of the surface of the colored layer side of the colored film of the present invention can be set to the arithmetic mean roughness Ra of the surface of the colored layer or the matte layer.

[0057] The arithmetic mean roughness (Ra) of the surface of the coloring layer side of the coloring film of the present invention refers to the value specified in JIS B0601:2013. Using HANDYSURF+ manufactured by Tokyo Seimitsu Corporation, surface measurements are performed at any three points (50 μm vertically × 50 μm horizontally) on the surface of the coloring layer side of the coloring film, and the average value of the three points is taken as the arithmetic mean roughness (Ra) of the surface of the coloring layer side of the coloring film.

[0058] From the viewpoint of ensuring design feasibility, concealment, and light-blocking properties, the total light transmittance of the colored film of the present invention is preferably 10% or less, more preferably 3% or less, and most preferably 1% or less. The total light transmittance is the total light transmittance Tt measured according to JIS K7105.

[0059] The coloring film of the present invention can be used as a coloring substrate. The coloring adhesive tape obtained by setting an adhesive layer on the coloring substrate is thin and can achieve alcohol resistance, curl resistance, and good adhesion between the film and the coloring layer. The coloring adhesive tape obtained using the coloring film of the present invention will be described later.

[0060] From the viewpoints of thinness, surface protection, and design, the coloring film of the present invention is preferably used for the protection of circuit components in electronic devices, and can be made into a coloring film for the protection of electronic circuit components.

[0061] II. Colored Adhesive Tape The colored adhesive tape of the present invention has a colored film as described in item "I. Colored film" above and an adhesive layer disposed on the surface of the colored film on the side of the resin film layer of the colored film, and the total thickness is 20 μm or less.

[0062] like Figure 2As illustrated, the colored adhesive tape 20 of the present invention has a colored film 10 and an adhesive layer 11. The colored film 10 has a resin film layer 1 and a colored layer 2 disposed on one side of the resin film layer 1. The adhesive layer 11 is disposed on the surface of the colored film 10 on the side of the resin film layer 1. In addition, the total thickness of the colored adhesive tape 20 is 20 μm or less.

[0063] The colored adhesive tape of the present invention is preferably used for protecting electronic components in very thin, space-constrained electronic devices. Furthermore, the colored adhesive tape of the present invention has the aforementioned colored film, thus exhibiting excellent visibility and concealment, resistance to curling, and good interlayer adhesion. In addition, the colored adhesive tape of the present invention has excellent alcohol resistance, preventing appearance defects caused by alcohol wiping during the bonding process with electronic components.

[0064] The total thickness of the colored adhesive tape of the present invention can be 20 μm or less, and from the viewpoint of balancing adhesion and thinness, it is preferably in the range of 4 to 15 μm, and more preferably in the range of 5 to 12 μm. By making the thickness of the colored adhesive tape 4 μm or more, suitable processability can be achieved, and by making the thickness of the colored adhesive tape 20 μm or less, suitable thinness can be achieved.

[0065] The adhesive strength of the colored adhesive tape of the present invention is preferably in the range of 2 to 10 N / 25 mm, more preferably in the range of 2.5 to 8 N / 25 mm, and even more preferably in the range of 3 to 6 N / 25 mm. If the adhesive strength of the colored adhesive tape of the present invention is too low, it is easy to peel off from the adhered object; if it is too high, the tape is easy to break during reprocessing. The adhesive strength of the colored adhesive tape is the 180° peel adhesion strength measured according to JIS Z0237-2000. The adhered object is a stainless steel plate, and the adhesion strength is the adhesion strength when peeled at a peel speed of 300 mm / min after 1 hour of application at 23°C and 50% RH.

[0066] [Coloring film] The details of the coloring film in the coloring adhesive tape of the present invention, as well as the resin film layer and coloring layer constituting the coloring film, are the same as those described in the above-mentioned "I. Coloring Film" section, and therefore are omitted here.

[0067] [Adhesive layer] The thickness of the adhesive layer in the colored adhesive tape of the present invention is only required to exhibit the desired adhesive strength and to ensure that the total thickness of the colored adhesive tape of the present invention is within the aforementioned range, preferably in the range of 1 μm to 6 μm, more preferably in the range of 2 μm to 5 μm, and even more preferably in the range of 2.5 μm to 4 μm. By setting the thickness of the adhesive layer to 1 μm or more, suitable adhesion can be achieved, and by setting it to 6 μm or less, suitable thinness can be achieved.

[0068] The adhesive used to form the adhesive layer of the colored adhesive tape of the present invention is not particularly limited, and may be appropriately selected from known adhesives such as acrylic adhesives, rubber adhesives, silicone adhesives, urethane adhesives, polyester adhesives, styrene-diene block copolymer adhesives, vinyl alkyl ether adhesives, polyamide adhesives, fluorinated adhesives, creep-modified adhesives, and radiation-curing adhesives. Two or more adhesives may be used alone or in combination.

[0069] Acrylic adhesives, in particular, are preferred due to their high bonding reliability. Acrylic adhesives contain acrylic polymers as adhesive components or main agents.

[0070] Acrylic polymers are polymers (copolymers) with alkyl (meth)acrylates as the main monomer component. They can be prepared by using monomers (copolymerizable monomers) capable of copolymerizing with (meth)alkyl esters, as needed. Examples of alkyl (meth)acrylates include methyl (meth)acrylate, ethyl (meth)acrylate, propyl (meth)acrylate, isopropyl (meth)acrylate, butyl (meth)acrylate, isobutyl (meth)acrylate, sec-butyl (meth)acrylate, tert-butyl (meth)acrylate, pentyl (meth)acrylate, hexyl (meth)acrylate, heptyl (meth)acrylate, octyl (meth)acrylate, 2-ethylhexyl (meth)acrylate, isooctyl (meth)acrylate, nonyl (meth)acrylate, isononyl (meth)acrylate, and so on. Decyl acrylate, isodecyl (meth)acrylate, undecyl (meth)acrylate, dodecyl (meth)acrylate, tridecyl (meth)acrylate, tetradecyl (meth)acrylate, pentadecyl (meth)acrylate, hexadecyl (meth)acrylate, heptadecanyl (meth)acrylate, octadecyl (meth)acrylate, nonadecanyl (meth)acrylate, eicosyl (meth)acrylate, and other C1-20 alkyl (meth)acrylates [preferably C4-18 alkyl (straight-chain or branched-chain) esters] are included. Alkyl (meth)acrylates can be appropriately selected based on target adhesion properties, etc. Alkyl (meth)acrylates can be used alone or in combination of two or more. Among these, acrylic polymers containing 90% by mass or more of butyl acrylate in the monomer components constituting the acrylic polymer are preferred due to their excellent adhesion and heat resistance. A further preferred content of butyl acrylate in the monomer components constituting the acrylic polymer is 95% by mass or more.

[0071] In addition, examples of comonomers capable of copolymerizing with the aforementioned (meth)alkyl esters include carboxyl-containing monomers or their anhydrides such as (meth)acrylic acid, itaconic acid, maleic acid, fumaric acid, crotonic acid, and isocrotonic acid; sulfonic acid-containing monomers such as sodium vinyl sulfonate; aromatic vinyl compounds such as styrene and substituted styrene; cyano-containing monomers such as acrylonitrile; olefins such as ethylene, propylene, and butadiene; vinyl esters such as vinyl acetate; vinyl chloride; amide-containing monomers such as acrylamide, methacrylamide, N-vinylpyrrolidone, and N,N-dimethyl(meth)acrylamide; hydroxyl-containing monomers such as (meth)acrylate and glycerol dimethacrylate; and amino-containing monomers such as (meth)acrylate aminoethyl ester and (meth)acryloylmorpholine. The copolymer includes monomers containing imide groups such as cyclohexylmaleimide and isopropylmaleimide; epoxy-containing monomers such as glycidyl methacrylate and methyl glycidyl methacrylate; isocyanate-containing monomers such as 2-methacryloyloxyethyl isocyanate; and multifunctional copolymer monomers such as triethylene glycol di(meth)acrylate, diethylene glycol di(meth)acrylate, ethylene glycol di(meth)acrylate, tetraethylene glycol di(meth)acrylate, neopentyl glycol di(meth)acrylate, 1,6-hexanediol di(meth)acrylate, trimethylolpropane tri(meth)acrylate, pentaerythritol tri(meth)acrylate, dipentaerythritol hexa(meth)acrylate, and divinylbenzene. Two or more copolymer monomers can be used alone or in combination. Modifying monomers with functional groups such as carboxyl groups are preferred as copolymer monomers. The acrylic polymer contains 0.5–4.0% by mass of acrylic acid in the monomer components constituting the acrylic polymer, exhibiting excellent adhesion and heat resistance, and is therefore preferred. A further preferred content of acrylic acid in the monomer components constituting the acrylic polymer is 1.5–3.0% by mass.

[0072] The mass-average molecular weight (Mw) of the acrylic polymer is preferably between 500,000 and 1,200,000, more preferably between 500,000 and 1,000,000. By ensuring that the mass-average molecular weight of the acrylic polymer falls within the above range, even as a film, it readily exhibits sufficient adhesion and heat resistance. The molecular weight is determined by GPC using styrene conversion.

[0073] Acrylic polymers can be prepared using conventional polymerization methods such as solution polymerization, emulsion polymerization, and ultraviolet irradiation polymerization.

[0074] The adhesive contains at least an acrylic polymer and may include additives such as crosslinking agents, tackifiers, softeners, plasticizers, fillers, anti-aging agents, and colorants as needed. In particular, to improve the adhesion and tensile strength and tensile breaking strength of the adhesive layer, the adhesive forming the adhesive layer preferably also contains a tackifier. Depending on the acrylic polymer used in the adhesive, the tensile strength and tensile breaking strength of the adhesive layer can be adjusted by appropriately adding a tackifier. Examples of tackifiers include rosin-based resins such as rosin and rosin ester compounds; terpene-based resins such as diterpene polymers and α-pinene-phenol copolymers; petroleum resins such as aliphatic (C5) and aromatic (C9) resins; and styrene-based resins, phenolic resins, and xylene resins. In adhesives using acrylic polymers with (meth)acrylate as the main monomer component, a mixture of rosin-based and styrene-based resins is preferred when considering both thin-film adhesion and heat resistance.

[0075] Furthermore, to improve the initial adhesion of the adhesive layer, the adhesive forming the adhesive layer preferably incorporates a tackifier that is liquid at room temperature. Examples of tackifiers that are liquid at room temperature include, for example, liquid resins containing the aforementioned tackifiers that are solid at room temperature, processing oils, polyester plasticizers, and low molecular weight liquid rubbers such as polybutene. Terpene phenolic resins are particularly preferred. Commercially available examples include YP-90L manufactured by Yasuhara Chemical Co., Ltd.

[0076] The amount of tackifier added is preferably 10 to 70 parts by weight relative to 100 parts by weight of the acrylic copolymer. More preferably, it is 20 to 60 parts by weight. By adding the tackifier, the adhesive strength can be improved.

[0077] There is no particular limitation on the gel fraction of the adhesive layer. Even if it is a film, it can easily exhibit sufficient adhesion and heat resistance. Therefore, it is preferably 5% to 50%, more preferably 10% to 45%, and even more preferably 13% to 35%. The gel fraction is: the mass of the dried insoluble components remaining after immersing the cured adhesive layer in toluene and leaving it for 24 hours is measured and expressed as a percentage relative to the original mass. Gel fraction = [(mass of the adhesive layer after toluene impregnation) / (mass of the adhesive layer before toluene impregnation)] × 100

[0078] In addition, the storage modulus of the adhesive layer is preferably 1×10 at 25°C and 1Hz. 4 ~4×10 5 Within the range of Pa. More preferably 5 × 10 Pa. 4 ~2×10 5 Within the range of Pa. By keeping the storage modulus of the adhesive layer within the above range, even for adhesive layers that are thin films, it is easy to achieve a high balance between wettability (initial tack) and adhesion.

[0079] [Remove the liner] To protect the adhesive layer, the colored adhesive tape of the present invention may have a release liner provided on the surface of the adhesive layer. A known release liner may be appropriately selected as the release liner. Products obtained by demolding the resin film exhibit excellent smoothness and are therefore preferred. Products obtained by demolding a polyester film with excellent heat resistance are particularly preferred. It should be noted that the total thickness of the colored adhesive tape in the present invention refers to the total thickness of the tape excluding the release liner.

[0080] To impart easy peeling properties, the surface of these release liner pads is preferably provided with a release treatment layer. This release treatment layer can be formed from various release agents used in the application of release liner pads for double-sided adhesive tapes; for example, silicone-based, fluorine-based, and long-chain alkyl-based release agents are preferred. Alternatively, the release treatment layer can be formed on the aforementioned resin film by lamination or coating.

[0081] The peel force of the release liner can be appropriately adjusted according to the usage method, etc. By setting the peel force on the adhesive layer to 0.01 to 2 N / 20 mm, preferably 0.05 to 0.15 N / 20 mm, deformation of the colored adhesive tape of the present invention can be easily suppressed when peeling off the release liner, which is therefore preferred. The peel force can be measured by peeling the release liner or the adhesive layer lined with 50 μm thick PET at a speed of 0.3 to 10 m / min in a 180° direction.

[0082] [Colored Adhesive Tape] The colored adhesive tape of the present invention typically has an adhesive layer on the surface of the resin film layer side. If a predetermined thickness is required, it is also acceptable to have an adhesive layer on the surface of the colored film layer side, or to have an adhesive layer on each of the two sides of the colored film. Furthermore, when the colored film has colored layers on both sides of the resin film layer, having an adhesive layer on the surface of the colored film layer side means that the adhesive layer is present on the surface of the colored layer disposed on one side of the resin film layer.

[0083] The colored adhesive tape of the present invention has at least an adhesive layer and a colored film. It may also include other functional layers besides those described above, provided the thickness is within a specified range. For example, a protective film layer may be provided on the surface of the colored layer. When a transparent protective film is provided on the surface of the tape during transportation, it is easy to prevent forgetting to peel off the glossy protective film.

[0084] The colored adhesive tape of the present invention is very thin and has the aforementioned colored film, thus exhibiting excellent visibility, concealment, and surface protection. Therefore, it is preferably used in space-constrained electronic devices, particularly for the protection and bonding of components used in portable electronic devices. In other words, the colored adhesive tape of the present invention can be manufactured as a colored adhesive tape for the protection of electronic circuit components.

Example

[0085] Hereinafter, embodiments of the present invention will be described in more detail. It should be noted that in the manufacture of adhesives, the "parts" indicating the amount of material to be mixed are expressed as "parts by mass".

[0086] (Manufacturing of Adhesive A) A solution polymer of acrylic acid polymer with a mass average molecular weight of 900,000 was prepared by solution polymerization of 97.98 parts of n-butyl acrylate, 2 parts of acrylic acid, 0.02 parts of 4-hydroxybutyl acrylate, and 0.2 parts of azobisisobutyronitrile (azobisisobutyronitrile) as a polymerization initiator in ethyl acetate solution at 80°C for 8 hours. Then, 5 parts of polymerized rosin ester (trade name "D-135", manufactured by Arakawa Chemical Co., Ltd.), 20 parts of disproportionated rosin ester (trade name "KE-100", manufactured by Arakawa Chemical Co., Ltd.), and 25 parts of petroleum resin (trade name "FTR6100") were added to 100 parts of this acrylic polymer, along with ethyl acetate, to prepare an adhesive solution with a solid content of 40%. Further, 0.8 parts of an isocyanate-based crosslinking agent (trade name "NC40", manufactured by DIC Co., Ltd.) were added, and the mixture was stirred until homogeneous to prepare adhesive A. Adhesive A had a gel fraction of 20% and a storage modulus of 9 × 10⁻⁶ at 25°C. 4 Pa.

[0087] (Manufacturing of Adhesive B) A solution of 97.98 parts n-butyl acrylate, 2 parts acrylic acid, 0.02 parts 4-hydroxybutyl acrylate, and 0.2 parts azobisisobutyronitrile (a polymerization initiator) was subjected to solution polymerization in ethyl acetate solution at 80°C for 8 hours to obtain an acrylic polymer with a mass average molecular weight of 900,000. Then, 5 parts of polymerized rosin ester (trade name "D-135", manufactured by Arakawa Chemical Co., Ltd.), 20 parts of disproportionated rosin ester (trade name "KE-100", manufactured by Arakawa Chemical Co., Ltd.), and 25 parts of petroleum resin (trade name "FTR6100") were added to 100 parts of this acrylic polymer, along with ethyl acetate, to prepare an adhesive solution with a solid content of 40%. Next, 10 parts of a black colorant "DICTON BLACK AR8555" (carbon black content: 45% (solids percentage), resin solids concentration: 49%) manufactured by DIC was added to the above adhesive solution and mixed thoroughly using a mixer. Then, 1.2 parts of an isocyanate-based crosslinking agent (trade name "NC40," manufactured by DIC) were added and stirred until homogeneous, thus preparing adhesive B. Adhesive B has a gel fraction of 20% and a storage modulus of 8 × 10⁻⁶ at 25°C. 4 Pa.

[0088] (Manufacturing of polyester polyol resin A) In a four-necked flask equipped with a stirrer, thermometer, reflux condenser, and nitrogen inlet tube, 50 parts by weight of isophthalic acid, 50 parts by weight of neopentyl glycol, 60 parts by weight of toluene, and 40 parts by weight of methyl ethyl ketone were added. The mixture was stirred and reacted at 80°C for 10 hours to obtain polyester polyol resin A with a resin solid content of 50% and a mass-average molecular weight of 40,000.

[0089] (Manufacturing of polyester polyol resin B) In a four-necked flask equipped with a stirrer, thermometer, reflux condenser, and nitrogen inlet tube, 40 parts by mass of isophthalic acid, 60 parts by mass of neopentyl glycol, 60 parts by mass of toluene, and 40 parts by mass of methyl ethyl ketone were added. The mixture was stirred and reacted at 80°C for 10 hours to obtain polyester polyol resin B with a resin solid content of 50% and a mass-average molecular weight of 40,000.

[0090] (Manufacturing of polyester polyol resin C) In a four-necked flask equipped with a stirrer, thermometer, reflux condenser, and nitrogen inlet tube, 60 parts by mass of isophthalic acid and 40 parts by mass of neopentyl glycol were added. The mixture was stirred and reacted at 80°C for 1 hour. Then, 60 parts by mass of toluene and 40 parts by mass of methyl ethyl ketone were added, and the mixture was stirred and reacted at 80°C for 10 hours to obtain polyester polyol resin C with a resin solid content of 50% and a mass-average molecular weight of 50,000.

[0091] (Manufacturing of polyester polyurethane resin D) In a four-necked flask equipped with a stirrer, thermometer, reflux condenser, and nitrogen inlet tube, 50 parts by weight of isophthalic acid, 50 parts by weight of neopentyl glycol, 80 parts by weight of toluene, and 40 parts by weight of methyl ethyl ketone were added. The mixture was stirred and reacted at 80°C for 4 hours. Then, 40 parts by weight of isophorone diisocyanate and 20 parts by weight of methyl ethyl ketone were mixed and reacted at 100°C for about 1 hour to obtain polyester polyurethane resin D with a resin solid content of 50% and a mass-average molecular weight of 40,000.

[0092] (Manufacturing of polyester polyol resin E) In a four-necked flask equipped with a stirrer, thermometer, reflux condenser, and nitrogen inlet tube, 65 parts by mass of isophthalic acid and 35 parts by mass of neopentyl glycol were added. The mixture was stirred and reacted at 80°C for 2 hours. Then, 60 parts by mass of toluene and 40 parts by mass of methyl ethyl ketone were added, and the mixture was stirred and reacted at 80°C for 10 hours to obtain polyester polyol resin E with a resin solid content of 50% and a mass-average molecular weight of 80,000.

[0093] (Manufacturing of polyester polyol resin F) In a four-necked flask equipped with a stirrer, thermometer, reflux condenser, and nitrogen inlet tube, 25 parts by mass of isophthalic acid, 75 parts by mass of neopentyl glycol, 60 parts by mass of toluene, and 40 parts by mass of methyl ethyl ketone were added. The mixture was stirred and reacted at 80°C for 10 hours to obtain polyester polyol resin F with a resin solid content of 50% and a mass-average molecular weight of 20,000.

[0094] (Manufacturing of Black Ink A) 100 parts by weight of polyester polyol resin A (50% by weight of resin solids), 40 parts by weight of carbon black "Carbon Special 250P" manufactured by Degussa, 23 parts by weight of methyl ethyl ketone, 13 parts by weight of toluene, 6 parts by weight of ethyl acetate, 3 parts by weight of n-propyl acetate, and 3 parts by weight of isopropanol were added and wet-dispersed in a sand mill for about 1 hour. Then, 2 parts by weight of curing agent "KR90" (a biuret form of hexamethylene diisocyanate, 40% by weight of solids) manufactured by DIC and 300 parts by weight of ethyl acetate were added to the product to prepare black ink A. The carbon black content in the solids of the black ink is 44% by weight.

[0095] (Manufacturing of Black Ink B) 100 parts by weight of polyester polyol resin B (50% solids content), 40 parts by weight of carbon black "Carbon Special 250P" manufactured by Degussa, 23 parts by weight of methyl ethyl ketone, 13 parts by weight of toluene, 6 parts by weight of ethyl acetate, 3 parts by weight of n-propyl acetate, and 3 parts by weight of isopropanol were added and wet-dispersed in a sand mill for about 1 hour. Then, 2 parts by weight of curing agent "KR90" (a biuret form of hexamethylene diisocyanate, 40% solids content) manufactured by DIC and 300 parts by weight of ethyl acetate were added to produce black ink B. The carbon black content in the solids content of the black ink is 44%.

[0096] (Manufacturing of black ink C) 100 parts by weight of polyester polyol resin C (50% solids content), 40 parts by weight of carbon black "Carbon Special 250P" manufactured by Degussa, 23 parts by weight of methyl ethyl ketone, 13 parts by weight of toluene, 6 parts by weight of ethyl acetate, 3 parts by weight of n-propyl acetate, and 3 parts by weight of isopropanol were added and wet-dispersed in a sand mill for about 1 hour. Then, 2 parts by weight of curing agent "KR90" (a biuret form of hexamethylene diisocyanate, 40% solids content) manufactured by DIC and 300 parts by weight of ethyl acetate were added to produce black ink C. The carbon black content in the solids content of the black ink is 44%.

[0097] (Manufacturing of black ink D) 100 parts by weight of polyester polyol resin A (50% solids content), 100 parts by weight of carbon black "Carbon Special 250P" manufactured by Degussa, 23 parts by weight of methyl ethyl ketone, 13 parts by weight of toluene, 6 parts by weight of ethyl acetate, 3 parts by weight of n-propyl acetate, and 3 parts by weight of isopropanol were added. The mixture was wet-dispersed in a sand mill for about 1 hour. Then, 2 parts by weight of curing agent "KR90" (a biuret form of hexamethylene diisocyanate, 40% solids content) manufactured by DIC and 300 parts by weight of ethyl acetate were added to produce black ink D. The carbon black content in the solids content of the black ink is 66%.

[0098] (Manufacturing of black ink E) 100 parts by weight of polyester polyurethane resin D (50% solids content), 40 parts by weight of carbon black "Carbon Special 250P" manufactured by Degussa, 23 parts by weight of methyl ethyl ketone, 13 parts by weight of toluene, 6 parts by weight of ethyl acetate, 3 parts by weight of n-propyl acetate, and 3 parts by weight of isopropanol were added and wet-dispersed in a sand mill for about 1 hour. Then, 2 parts by weight of curing agent "KR90" (a biuret form of hexamethylene diisocyanate, 40% solids content) manufactured by DIC and 300 parts by weight of ethyl acetate were added to produce black ink E. The carbon black content in the solids content of the black ink is 44%.

[0099] (Manufacturing of black ink F) 100 parts by weight of polyester polyol resin E (50% solids content), 40 parts by weight of carbon black "Carbon Special 250P" manufactured by Degussa, 23 parts by weight of methyl ethyl ketone, 13 parts by weight of toluene, 6 parts by weight of ethyl acetate, 3 parts by weight of n-propyl acetate, and 3 parts by weight of isopropanol were added. The mixture was wet-dispersed in a sand mill for about 1 hour. Then, 2 parts by weight of curing agent "KR90" (a biuret form of hexamethylene diisocyanate, 40% solids content) manufactured by DIC and 300 parts by weight of ethyl acetate were added to produce black ink F. The carbon black content in the solids content of the black ink was 44%.

[0100] (Manufacturing of black ink G) 100 parts by weight of polyester polyol resin F (50% solids content), 40 parts by weight of carbon black "Carbon Special 250P" manufactured by Degussa, 23 parts by weight of methyl ethyl ketone, 13 parts by weight of toluene, 6 parts by weight of ethyl acetate, 3 parts by weight of n-propyl acetate, and 3 parts by weight of isopropanol were added and wet-dispersed in a sand mill for about 1 hour. Then, 2 parts by weight of curing agent "KR90" (a biuret form of hexamethylene diisocyanate, 40% solids content) manufactured by DIC and 300 parts by weight of ethyl acetate were added to produce black ink G. The carbon black content in the solids content of the black ink is 44%.

[0101] 1. Manufacturing of coloring film [Example 1-1] Black ink A was gravure-coated onto a Toray-manufactured polyester film Lumirror 2F51 (thickness: 2.0 μm, tensile strength 3 N / 10 mm) to a dry thickness of 3.0 μm. The film was then cured at 40°C for 1 day to obtain black ink-coated film A (colored film A). The glass transition temperature of the cured product of the polyester polyol resin A and the curing agent, i.e., the colored layer of colored film A, is 51.0°C. It should be noted that the glass transition temperature of the colored layer is a value obtained using DSC according to ISO 3146. The same applies below.

[0102] [Examples 1-2] Black ink B was used instead of black ink A, and otherwise, a black ink coated film B (colored film B) was obtained in the same manner as in Examples 1-1. The glass transition temperature of the colored layer of the colored film B, which is the cured product of the polyester polyol resin B of black ink B and the curing agent, is 48.0°C.

[0103] [Examples 1-3] Using black ink C instead of black ink A, the same procedure as in Example 1-1 was followed to obtain a black ink coated film C (colored film C). The glass transition temperature of the colored layer of the colored film C, which is the cured product of the polyester polyol resin B of black ink C and the curing agent, is 62.0°C.

[0104] [Examples 1-4] The drying thickness of black ink A was set to 4.0 μm instead of 3.0 μm, and otherwise, the black ink coating film D (colored film D) was obtained in the same manner as in Examples 1-1. The glass transition temperature of the colored layer of the colored film D, which is the cured product of the reaction between the polyester polyol resin A of black ink A and the curing agent, is 51.0°C.

[0105] [Examples 1-5] The drying thickness of black ink A was set to 1.5 μm instead of 3.0 μm, and otherwise, the black ink coating film E (colored film E) was obtained in the same manner as in Examples 1-1. The glass transition temperature of the colored layer of the colored film E, which is the cured product of the reaction between the polyester polyol resin A of black ink A and the curing agent, is 51.0 °C.

[0106] [Examples 1-6] Toray-manufactured polyester film 4AF53 (thickness: 3.5 μm, tensile strength: 12 N / 10 mm) was used instead of Toray-manufactured polyester film Lumirror 2F51. Otherwise, the same as in Example 1-1, a black ink-coated film (colored film F) was obtained. The glass transition temperature of the colored layer of the colored film F, which is the cured product of the reaction between the polyester polyol resin A of black ink A and the curing agent, is 51.0 °C.

[0107] [Examples 1-7] Using black ink D instead of black ink A, the same procedure as in Example 1-1 was followed to obtain a black ink coated film G (colored film G). The glass transition temperature of the colored layer of the colored film G, which is the cured product of the reaction between the polyester polyol resin A of black ink D and the curing agent, is 51.0°C.

[0108] [Comparative Example 1-1] Black ink E was used instead of black ink A, and the dried thickness of black ink E was set from 3.0 μm to 1.5 μm. Mitsubishi Resin-manufactured polyester film K330-4.5W (thickness: 4.5 μm, tensile strength: 6.5 N / 10 mm) was used instead of Toray's Lumirror 2F51 polyester film. Otherwise, the same procedure as in Example 1-1 was followed to obtain a black ink coated film H (colored film H). The glass transition temperature of the cured product of the polyester polyurethane resin D of black ink E and the curing agent, i.e., the colored layer of colored film H, is -20.0 °C.

[0109] [Comparative Examples 1-2] Black ink F was used instead of black ink A, and otherwise, the same as in Example 1-1 was used to obtain black ink coated film I (colored film I). The glass transition temperature of the colored layer of colored film I, which is the product of the reaction between the polyester polyol resin E of black ink F and the curing agent, is 70.0°C.

[0110] [Comparative Examples 1-3] Using black ink G instead of black ink A, the same procedure as in Example 1-1 was followed to obtain a black ink coated film J (colored film J). The glass transition temperature of the colored layer of the colored film J, which is the cured product of the reaction between the polyester polyol resin F of black ink G and the curing agent, is 41.0°C.

[0111] [Comparative Examples 1-4] Using a polyester film S16 (thickness: 16 μm, tensile strength: 11 N / 10 mm) manufactured by Uniqlo instead of the polyester film Lumirror 2F51 manufactured by Toray, a black ink-coated film K (colored film K) was obtained in the same manner as in Examples 1-1. The glass transition temperature of the colored layer of the colored film K, which is the cured product of the polyester polyol resin A of black ink A and the curing agent, is 51.0 °C.

[0112] [Comparative Examples 1-5] A Chinese-made polyester film (thickness: 0.7 μm, tensile strength: 1.0 N / 10 mm) was used instead of the Toray-manufactured polyester film Lumirror 2F51. Otherwise, the same procedure as in Example 1-1 was followed to obtain a black ink-coated film L (colored film L). The glass transition temperature of the colored layer of the colored film L, which is the cured product of the polyester polyol resin A of the black ink A and the curing agent, is 51.0 °C.

[0113] [Comparative Examples 1-6] The drying thickness of black ink A was set to 0.5 μm instead of 3.0 μm, and otherwise, the black ink coating film M (colored film M) was obtained in the same manner as in Examples 1-1. The glass transition temperature of the colored layer of the colored film M, which is the cured product of the reaction between the polyester polyol resin A of black ink A and the curing agent, is 51.0°C.

[0114] [Comparative Examples 1-7] The drying thickness of black ink A was set to 6.0 μm instead of 3.0 μm, and otherwise, the black ink coating film N (colored film N) was obtained in the same manner as in Example 1-1. The glass transition temperature of the colored layer of the colored film N, which is the cured product of the reaction between the polyester polyol resin A of black ink A and the curing agent, is 51.0°C.

[0115] 2. Manufacturing of Colored Adhesive Tape [Example 2-1] First, the adhesive A is applied to the release film ("PET25×J0L" manufactured by Nippa Corporation) with a dry thickness of 2.0 μm using a roller coater. After drying at 100°C for 1 minute, it is bonded to the polyester film surface of the colored film A and further cured at 40°C for 2 days to obtain the colored adhesive tape.

[0116] [Example 2-2] The colored adhesive tape is obtained by using colored film B instead of colored film A, otherwise the same as in Example 2-1.

[0117] [Examples 2-3] The colored adhesive tape is obtained by using colored film C instead of colored film A, otherwise the same as in Example 2-1.

[0118] [Examples 2-4] The colored adhesive tape is obtained by replacing the colored film A with colored film D, otherwise the same as in Example 2-1.

[0119] [Examples 2-5] The colored adhesive tape is obtained by replacing the colored film A with colored film E, otherwise the same as in Example 2-1.

[0120] [Examples 2-6] The colored adhesive tape is obtained by replacing the colored film A with colored film F, otherwise the same as in Example 2-1.

[0121] [Examples 2-7] The colored adhesive tape is obtained by replacing the colored film A with colored film G, otherwise the same as in Example 2-1.

[0122] [Examples 2-8] The dried thickness of adhesive A was changed from 2.0 μm to 5.0 μm, and otherwise the same as in Example 2-1 was obtained to obtain the colored adhesive tape.

[0123] [Examples 2-9] The colored adhesive tape is obtained in the same manner as in Example 2-1, except that adhesive B is used instead of adhesive A.

[0124] [Comparative Example 2-1] First, the adhesive A is applied to the release film ("PET25×J0L" manufactured by Nippa Corporation) with a dry thickness of 2.0 μm using a roller coater. After drying at 100°C for 1 minute, it is bonded to the polyester film surface of the colored film H and further cured at 40°C for 2 days to obtain the colored adhesive tape.

[0125] [Comparative Example 2-2] The colored adhesive tape was obtained by using colored film I instead of colored film H, otherwise the same as in Comparative Example 2-1.

[0126] [Comparative Examples 2-3] The colored adhesive tape was obtained by using colored film J instead of colored film H, otherwise the same as in Comparative Example 2-1.

[0127] [Comparative Examples 2-4] The colored adhesive tape was obtained in the same manner as in Comparative Example 2-1, except that colored film K was used instead of colored film H.

[0128] [Comparative Examples 2-5] The colored adhesive tape was obtained by replacing the colored film H with the colored film L, otherwise the same as in Comparative Example 2-1.

[0129] [Comparative Examples 2-6] The colored adhesive tape was obtained by using colored film M instead of colored film H, otherwise the same as in Comparative Example 2-1.

[0130] [Comparative Examples 2-7] The colored adhesive tape was obtained in the same manner as in Comparative Example 2-1, except that colored film N was used instead of colored film H.

[0131] [evaluate] (The hardness of the pencil in the colored layer) The surface of the colored layer of the colored film is evaluated based on the scratch hardness (pencil test) according to JIS K5600. It should be noted that when the resin film cracks, a colored layer is coated onto a thick PET film and used as the evaluation object; the pencil hardness of the colored layer is then determined.

[0132] (Arithmetic mean roughness Ra) According to JIS B0601, using HANDYSURF+ manufactured by Tokyo Seimitsu Co., Ltd., surface measurements are performed at any three points on the surface of the colored layer of the colored film, and the average value of the three measured points is taken as the arithmetic mean roughness Ra of the surface of the colored layer side of the colored film.

[0133] (Thinness) The thickness of the colored adhesive tape was measured in 0.1 μm units using Nikon's "DIGIMICRO MF-501", "MCF-101", and "MS-31G" and evaluated according to the following benchmarks. ◎: Colored adhesive tape with a thickness of 7μm or less is evaluated as having excellent thinness performance. 〇: Colored adhesive tapes with a thickness exceeding 7 μm but less than 20 μm are evaluated as having practically sufficient thinness. ×: Colored adhesive tapes with a thickness exceeding 20 μm are considered to lack sufficient thinness performance.

[0134] (Adhesive strength) Cut the colored adhesive tape into 25mm wide pieces and, according to JIS Z0237, use a Tensilon tensile testing machine to determine the peel adhesion (peel angle: 180°, tensile speed: 300mm / min, 23℃×50%RH, substrate: stainless steel plate, adhesion time: 1 hour).

[0135] (Holding force) The colored adhesive tape was cut into 25mm wide pieces. According to JIS Z0237, a load of 100g (25mm×25mm) was applied in the vertical direction, and the drop time was measured in an atmosphere of 100°C.

[0136] (Alcohol resistance) The same area of ​​the colored film's colored layer side was wiped 50 times with a cotton swab soaked in ethanol. The number of wipings and the occurrence of color loss from the colored layer were evaluated. ◎: The number of times is 50 or more. 〇: The number of times is more than 25 and less than 50. ×: The number of times is less than 24.

[0137] (Resistance to curling) Place a 100mm×100mm colored film on a flat table and evaluate the curling. ◎: No floating at the end face - floating within 3mm 〇: The end face rises by more than 3mm but less than 5mm ×: The surface rises more than 5mm

[0138] (Seamless fit) Apply cellophane tape manufactured by NICHIBAN to the colored layer side of the colored film. Press the tape together by rubbing it with the pad of your thumb 5 or 6 times. After pressing, leave it for about 1 minute, then grasp one end of the cellophane tape on both sides and peel it off forcefully in a 180° direction (peeling speed: about 50m / min). Evaluate the condition of the adhesive tape after peeling. ◎: No coloring layer peeling off or the resin film being torn apart. 〇: Less than 5% of the colored layer peels off in the area where cellophane tape is applied (the colored layer can be visually confirmed to have shifted toward the cellophane tape side, but cannot be visually determined on the film). △: In the area where cellophane tape is applied, more than 5% but less than 30% of the colored layer peels off. ×: In the area where cellophane tape was applied, more than 30% of the colored layer peeled off.

[0139] The evaluation results are shown in the table below.

[0140] Table 1

[0141] Table 2

[0142] The colored film obtained in the examples and the colored adhesive tape using the colored film are thin and exhibit excellent alcohol resistance, curl resistance, and interlayer adhesion between the colored layer and the resin film. On the other hand, the colored film obtained in the comparative examples and the colored adhesive tape using the colored film cannot achieve a balance of alcohol resistance, curl resistance, interlayer adhesion between the colored layer and the resin film, and thinness. Symbol Explanation

[0143] 1…Resin film layer 2…shading layer 10…Coloring film 11… Adhesive layer 20… Colored adhesive tape.

Claims

1. A colored film, characterized by, It has a resin film layer and a coloring layer disposed on one side of the resin film layer. The thickness of the resin film layer is 1 μ m ~ 12 μ in the range of m, The coloring layer comprises a cured resin and a coloring material, and its glass transition temperature is in the range of 45°C to 65°C. The thickness of the colored layer is 1 μ m ~ 4 μ m in the range, The cured resin is a cured resin composition comprising a polyol component mainly composed of polyester polyol and an isocyanate component mainly composed of polyfunctional isocyanate.

2. The coloring film according to claim 1, wherein, The pencil hardness of the colored layer is in the range of HB to 2H.

3. The coloring film according to claim 1 or 2, wherein, The arithmetic average roughness Ra of the surface of the colored layer side of the colored film is 0.2 μ m ~ 0.6 μ m is in the range of 0.

4. The coloring film according to claim 1 or 2, wherein, The polyol component is a polyester polyol, and the isocyanate component is a polyfunctional isocyanate.

5. The coloring film according to claim 1 or 2, wherein, The weight-average molecular weight of the polyester polyol is in the range of 1,000 to 400,000.

6. The coloring film according to claim 1 or 2, wherein, The resin film layer is a polyester film layer.

7. The coloring film according to claim 1 or 2, wherein, The coloring film contains carbon black as the coloring material.

8. The coloring film according to claim 1 or 2, wherein, The colored film is used for the protection of electronic circuit components.

9. The coloring film according to claim 1 or 2, wherein, The coloring layer is a black coloring layer.

10. The coloring film according to claim 1 or 2, wherein, The coloring layer is a white coloring layer.

11. The coloring film according to claim 1 or 2, wherein, The cured resin is a polyester resin that is a cured product of polyester polyol and diisocyanate. The polyester polyol is a copolymer of one or more dicarboxylic acids and one or more diols. The diisocyanate is selected from at least one of aliphatic diisocyanates, adducts of the aliphatic diisocyanates, isocyanurates, biuretates, and ureocarbamates.

12. The coloring film according to claim 11, wherein, The weight-average molecular weight of the polyester polyol is in the range of 1,000 to 400,000.

13. The coloring film according to claim 11, wherein, The dicarboxylic acid is selected from succinic acid, adipic acid, azelaic acid, sebacic acid, dodecanoic acid, maleic acid, fumaric acid, 1,3-cyclopentanedicarboxylic acid, 1,4-cyclohexanedicarboxylic acid, terephthalic acid, isophthalic acid, phthalic acid, naphthalenedicarboxylic acid, biphenyl dicarboxylic acid, 1,2-bis(phenoxy)ethane-p,p'-dicarboxylic acid, and anhydrides or ester-forming derivatives of these dicarboxylic acids.

14. The coloring film according to claim 13, wherein, The naphthalene dicarboxylic acid is 1,4-naphthalene dicarboxylic acid, 2,5-naphthalene dicarboxylic acid, or 2,6-naphthalene dicarboxylic acid.

15. The coloring film according to claim 11, wherein, The diols are selected from ethylene glycol, propylene glycol, 1,4-butanediol, 1,5-pentanediol, 1,6-hexanediol, neopentanediol, methylpentanediol, dimethylbutanediol, butyl ethyl propylene glycol, diethylene glycol, triethylene glycol, tetraethylene glycol, dipropylene glycol, tripropylene glycol, dihydroxyethoxybenzene, 1,4-cyclohexanediol, 1,4-cyclohexanediol, polycaprolactone diol, dimer diol, bisphenol A, and hydrogenated bisphenol A.

16. The coloring film according to claim 15, wherein, The propylene glycol is 1,3-propanediol.

17. A colored adhesive tape, characterized in that, The colored film having any one of claims 1 to 16 and an adhesive layer disposed on the resin film layer side of the colored film, The total thickness of the colored adhesive tape is 20. μ Below m.

18. The colored adhesive tape according to claim 17, wherein, The colored adhesive tape is used for the protection of electronic circuit components.

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