Decorative film

Abstract

The present invention provides a polyurethane-based decorative film that combines multiple functions, such as colouring and pigment protection, in a single product. A decorative film according to one embodiment comprises: a transparent top layer comprising a transparent thermoplastic polyurethane elastomer film; and a colored acrylic pressure-sensitive adhesive layer. The decorative film has a tensile strength at 2% strain of 20 N / 25 mm or less and an elongation of 150% or more.

Description

Technical Field

[0001] The present disclosure relates to a decorative film. Background Art

[0002] Colored decorative films have been widely used for interior and exterior applications in vehicles (including cars, trains, ships and other vehicles) and buildings. Colored decorative films are used, for example, in the production of vehicles or the construction of buildings, or in the repair of vehicles and buildings.

[0003] Car wrapping is a known application of decorative films. In car wrapping, the appearance of a car can be changed by applying a special decorative film to the car body. Tinted films based on polyvinyl chloride (PVC) are often used in car wrap applications to allow stretching and adhesion of the decorative film even on surfaces with large curvatures.

[0004] Meanwhile, in order to protect the paint of the car from flying stones, scratches, etc., it is known to cover part or all of the car body with a transparent film. The transparent thermoplastic polyurethane elastomer film is suitable for use as a paint protection film because the transparent thermoplastic polyurethane elastomer film has useful properties such as anti-chipping, scratch resistance and self-healing properties.

[0005] Patent document 1 (JP 2009-203370 A) discloses "a marking film comprising: a colored base film layer; and an adhesive layer comprising an acrylic white adhesive, the adhesive layer being laminated on the colored base film layer, wherein the acrylic white adhesive contains a carboxyl-containing (meth)acrylic polymer, 25 parts by mass to 150 parts by mass of a white pigment relative to 100 parts by mass of the carboxyl-containing (meth)acrylic polymer, and an amino-containing (meth)acrylic polymer not containing an aromatic vinyl monomer".

[0006] Patent document 2 (JP 2003-183602 A) discloses "a decorative adhesive sheet characterized by comprising an adhesive containing: 3 parts by weight to 50 parts by weight of a white pigment relative to 100 parts by weight of a base polymer of the adhesive, and 0.3% by weight to 2% by weight of an aluminum metal sheet relative to the amount of the added white pigment, the adhesive being laminated on one surface of a colored film having a total light transmittance of 3% to 80%."

[0007] Patent document 3 (JP 2007-269928 A) discloses “an adhesive sheet comprising: a base film composed of a single layer; and an adhesive layer, wherein the base film has a specular glossiness Gs (60°) of 80% or more, and a storage elastic modulus of the base film at any temperature of 70° C. to 90° C. of 1.0×10 1 to 2.8×10 2MPa."

[0008] Patent document 4 (JP 2013-237216 A) discloses "a decorative sheet comprising a surface layer and an adhesive layer, wherein the surface layer is a polyurethane layer obtained by crosslinking using a curing agent in an amount of 0.1 to 2.0 equivalents per acid value of a carboxyl group, and applying and drying a linear polyurethane resin obtained by reacting a diamine chain extender with a polyurethane prepolymer obtained by reacting a polycarbonate diol having an alicyclic structure, an aliphatic diol having a carboxyl group, and an isocyanate containing 4,4'-cyclohexylmethane diisocyanate, wherein the molecular weight of the linear polyurethane resin is in the range of about 50,000 to about 350,000, and the linear polyurethane resin exhibits an acid value in the range of about 20.0 mg·KOH / g to about 30.0 mg·KOH / g." Summary of the invention

[0009] Technical issues

[0010] In the application of automobile film, the decorative film is required to have multiple functions, such as coloring and pigment protection. For example, a colored decorative film is applied to the automobile body, and then a transparent protective film is applied to the colored decorative film to achieve coloring and pigment protection. However, when the colored decorative film and the transparent protective film are applied to and laminated on the automobile body, durability, heat shrinkage or weather resistance problems of the laminate may occur.

[0011] Therefore, there is a need for a decorative film having multiple functions in a single product, such as coloration and pigment protection.Furthermore, the decorative film is advantageously a non-PVC based decorative film.

[0012] It is conceivable that a colored polyurethane film is used as a solution to this demand. Polyurethane films are usually colored by printing ink containing a pigment and a binder on the surface of the polyurethane film to form a decorative layer (print layer) on the polyurethane film. However, when the polyurethane film is provided with a decorative layer (print layer) containing a material different from the material of the polyurethane, the elongation characteristics originally possessed by the polyurethane film may deteriorate. When the color of the decorative layer changes, the degree of degradation of the elongation characteristics of the polyurethane film may vary according to the pigment or binder contained in the decorative layer. This is considered to be because the pigment acts not only as a colorant but also as a filler in the decorative layer, and the functional group or polar group that the pigment may have affects the physical properties of the binder. When the content of the pigment is increased to obtain a high color, the physical properties of the adhesive are more likely to be affected by the pigment. As described above, there are technical difficulties in the coloring method of the polyurethane film, and it is generally difficult to color the polyurethane film without damaging the inherent physical properties of the polyurethane film.

[0013] The present disclosure provides a polyurethane-based decorative film having multiple functions, such as coloring and pigment protection, in a single product.

[0014] Solution to the problem

[0015] The present inventors have discovered that by combining a transparent thermoplastic polyurethane elastomer film with a pigmented acrylic pressure-sensitive adhesive layer, a polyurethane-based decorative film can be produced having multiple functions in a single product, such as coloration and pigment protection.

[0016] According to one embodiment, a decorative film is provided, comprising: a transparent top layer comprising a transparent thermoplastic polyurethane elastomer film; and a colored acrylic pressure-sensitive adhesive layer, wherein the decorative film has a tensile strength of 20 N / 25 mm or less at 2% strain and an elongation of 150% or more.

[0017] Advantageous Effects of the Invention

[0018] According to the present disclosure, there is provided a polyurethane-based decorative film having multiple functions, such as coloring and pigment protection, in a single product.

[0019] It should be noted that the above description is not to be construed as a disclosure of all embodiments of the present invention and advantages associated with the present invention. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Figure 1 is a schematic cross-sectional view of a decorative film according to one embodiment.

[0021] Figure 2 : is a graph showing the relationship between the elongation (%) and the tensile strength (N / 25mm) of the decorative films of Examples 1 to 3 and Reference Example 1. DETAILED DESCRIPTION

[0022] Hereinafter, the present invention will be described in more detail with reference to the accompanying drawings for the purpose of explaining representative embodiments of the present invention, but the present invention is not limited to these embodiments.

[0023] In the present disclosure, the term "(meth)acrylic" refers to acrylic or methacrylic, and the term "(meth)acrylate" refers to acrylate or methacrylate.

[0024] In the present disclosure, the term "film" encompasses articles referred to as "sheets."

[0025] In the present disclosure, "pressure-sensitive adhesive (adhesion)" refers to a material or composition that adheres to various surfaces in a short time by applying a small pressure within a use temperature range (such as 0°C to 50°C) and does not exhibit a phase change (from liquid to solid). In the present disclosure, "adhesive (adhesion)" can be used interchangeably with "pressure-sensitive adhesive (adhesion)".

[0026] In the present disclosure, the term "transparent" refers to a total light transmittance of about 80% or more, preferably about 85% or more, or about 90% or more in the visible light region (wavelength range of 380 nm to 780 nm) measured according to JIS K 7375: 2008. The upper limit of the total light transmittance is not particularly limited, and may be, for example, about less than 100%, about less than 99% or less, or about less than 98% or less.

[0027] In the present disclosure, "non-PVC-based" means that the decorative film is substantially free of polyvinyl chloride, for example, a polyvinyl chloride film or a polyvinyl chloride layer. In one embodiment, the polyvinyl chloride content of the decorative film is about 1 mass % or less, about 0.5 mass % or less, or about 0.1 mass % or less.

[0028] In this disclosure, "weight average molecular weight" is the molecular weight measured by gel permeation chromatography (GPC) calibrated with polystyrene standards.

[0029] In the present disclosure, “disposed on” refers not only to the case of being directly disposed on but also to the case of being indirectly disposed on, that is, disposed on via another material or layer.

[0030] In this disclosure, "titanium oxide" may be used interchangeably with "titanium dioxide (TiO2)".

[0031] A decorative film of one embodiment includes: a transparent top layer including a transparent thermoplastic polyurethane elastomer film; and a colored acrylic pressure-sensitive adhesive layer, wherein the decorative film has a tensile strength of 20 N / 25 mm or less at 2% strain and an elongation of 150% or more. In the decorative film of the present disclosure, the physical properties of the decorative film (such as elongation, tensile strength, and breaking strength) are mainly determined by the physical properties of the transparent thermoplastic polyurethane elastomer film contained in the transparent top layer, and are hardly affected by the colored acrylic pressure-sensitive adhesive layer. Therefore, the decorative film of the present disclosure can maximize the use of the inherent physical properties of the transparent thermoplastic polyurethane elastomer film. In addition, since the colored acrylic pressure-sensitive adhesive layer has the function of coloring the decorative film, various product designs using various pigments are possible without damaging the physical properties of the transparent thermoplastic polyurethane elastomer film.

[0032] In one embodiment, the decorative film includes a transparent top layer and a colored acrylic pressure-sensitive adhesive layer. The phrase "including a transparent top layer and a colored acrylic pressure-sensitive adhesive layer" means that the decorative film does not include any layer other than the transparent top layer, the colored adhesive layer, and the liner to be removed when used. The decorative film of this embodiment has a simple layer structure and can therefore more advantageously adapt to the regulations on flame retardancy in each country.

[0033] Figure 1 A schematic cross-sectional view of a decorative film of one embodiment is shown. The decorative film 10 includes a transparent top layer 12 and a pigmented acrylic pressure-sensitive adhesive layer 14. The transparent top layer 12 includes a transparent thermoplastic polyurethane elastomer film 122. Figure 1 In FIG. 1 , a topcoat layer 124 disposed on a transparent thermoplastic polyurethane elastomer film 122 is shown as an optional component of the transparent top layer 12 . Figure 1 The decorative film 10 further includes, as an optional component, a liner 16. The liner 16 is removed before adhering the decorative film 10 to an adherend.

[0034] The transparent top layer can be a single layer or multiple layers. In one embodiment, the transparent top layer is a single layer and, in other words, comprises a transparent thermoplastic polyurethane elastomer film. This embodiment is advantageous from the perspective of the physical properties of the decorative film, the material cost of producing the decorative film, and the method of producing the decorative film, because the layer structure is simple and no interlayer delamination occurs in the transparent top layer. In another embodiment, the transparent top layer is multiple layers and comprises another layer, such as a topcoat layer disposed on the transparent thermoplastic polyurethane elastomer film.

[0035] Transparent thermoplastic polyurethane elastomer film is not particularly limited, as long as it is a film including transparent thermoplastic polyurethane elastomer. Thermoplastic polyurethane elastomer can give decorative film high strength, weather resistance and durability. Thermoplastic polyurethane elastomer is a block copolymer comprising a hard segment and a soft segment, each of which has a urethane bond in its molecule, and is synthesized by the addition polymerization of polyols and polyisocyanates. The hard segment is a molecular constraint component that prevents polyurethane plastic deformation, and the soft segment gives polyurethane elastomer properties. The hard segment of thermoplastic polyurethane elastomer is usually composed of diisocyanate and short-chain diols (chain extenders) when necessary. The soft segment of thermoplastic polyurethane elastomer is usually composed of long-chain polyols. One type of thermoplastic polyurethane elastomer can be used alone, or two or more types of thermoplastic polyurethane elastomers can be used in combination.

[0036] Examples of long-chain polyols include polyester polyols, polylactone polyols, polyether polyols, and polycarbonate polyols. Examples of polyester polyols include poly(ethylene glycol adipate) diol, poly(1,4-butylene glycol adipate) diol, and poly(1,6-hexanediol adipate) diol. Examples of polylactone polyols include poly(ε-caprolactone) diol. Examples of polyether polyols include poly(oxyethylene) diol, poly(oxypropylene) diol, and poly(oxytetramethylene) diol. Examples of polycarbonate polyols include poly(hexanediol-1,6-carbonate) diol. Long-chain polyols are preferably diols. Long-chain polyols are preferably aliphatic polyester polyols because aliphatic polyester polyols have excellent transparency and non-yellowing properties. One type of long-chain polyol can be used alone, or two or more types of long-chain polyols can be used in combination.

[0037] Examples of short-chain polyols include ethylene glycol, 1,2-propylene glycol, 1,3-propylene glycol, 1,2-butylene glycol, 1,3-butylene glycol, 1,4-butylene glycol, 2-methyl-1,3-propanediol, and 1,4-hexanediol. The short-chain polyol is preferably a diol. The short-chain polyol is preferably an aliphatic polyol because the aliphatic polyester polyol has excellent transparency and non-yellowing properties. One type of short-chain polyol may be used alone, or two or more types of short-chain polyols may be used in combination.

[0038] Chain extenders other than short-chain polyols may also be used. Examples of chain extenders include polyamines such as ethylenediamine, hexamethylenediamine, xylene diamine, isophorone diamine, and ethylenetriamine; and amino alcohols such as monoethanolamine, diethanolamine, and monopropanolamine. Chain extenders other than short-chain polyols may be used alone or in combination of two or more types.

[0039] Examples of diisocyanates include aromatic diisocyanates such as 4,4'-diphenylmethane diisocyanate (MDI), 2,4-toluene diisocyanate (2,4-TDI), 2,6-toluene diisocyanate (2,6-TDI), meta-xylylene diisocyanate, 1,4-phenylene diisocyanate (PPDI) and 1,5-diisocyanatonaphthalene (NDI); aliphatic diisocyanates such as hexamethylene diisocyanate (HDI); and alicyclic diisocyanates such as 4,4'-dicyclohexylmethane diisocyanate, 1-isocyanato-3-isocyanatomethyl-3,5,5-trimethylcyclohexane (IPDI), trans-cyclohexane-1,4-diisocyanate, hydrogenated xylylene diisocyanate and hydrogenated MDI. The diisocyanate is preferably an aliphatic diisocyanate or an alicyclic diisocyanate. One type of diisocyanate may be used alone, or two or more types of diisocyanates may be used in combination.

[0040] The thermoplastic polyurethane elastomer is preferably an aliphatic or alicyclic thermoplastic polyurethane elastomer, since the aliphatic or alicyclic thermoplastic polyurethane elastomer has good weather resistance and non-yellowing properties.

[0041] The elastomeric properties of the thermoplastic polyurethane elastomer can be adjusted by the weight average molecular weight of the thermoplastic polyurethane elastomer.

[0042] The 100% elastic modulus (storage elastic modulus at 100% elongation) of the thermoplastic polyurethane elastomer may be, for example, about 100 MPa or more, or about 250 MPa or more, and may be about 2000 MPa or less, or about 1500 MPa or less at 20°C.

[0043] The thermoplastic polyurethane elastomer may include additives such as a UV absorber, a light stabilizer, or a heat stabilizer as an optional component.

[0044] The thickness of the thermoplastic polyurethane elastomer film is not particularly limited, and may be, for example, about 5 μm or more, about 10 μm or more, or about 25 μm or more, and may be about 500 μm or less, about 300 μm or less, or about 200 μm or less.

[0045] The transparent top layer may include a topcoat layer on the opposite side of the colored acrylic pressure-sensitive adhesive layer of the transparent thermoplastic polyurethane elastomer film. Forming the topcoat layer can improve the weather resistance, solvent resistance, chemical resistance and scratch resistance of the decorative film. The topcoat layer may include, for example, polyurethane acrylic resin, acrylic resin, fluorine-based resin or a combination of these resins.

[0046] The thickness of the topcoat layer may be, for example, about 1 μm or more, about 1.5 μm or more, or about 2 μm or more, and may be about 20 μm or less, about 10 μm or less, or about 5 μm or less.

[0047] The transparent top layer can be colored or colorless. The transparent top layer can include a substantially smooth surface, or can include a rough or structured surface formed by a surface treatment such as embossing. The appearance or shape of the transparent top layer is as described above, and the appearance or shape can impart various decorative properties to the decorative film.

[0048] In one embodiment, the total light transmittance of the transparent top layer in the wavelength range of 380 nm to 780 nm is about 80% or greater. In this embodiment, the color of the colored acrylic pressure-sensitive adhesive layer can be visually recognized through the transparent top layer without any change.

[0049] The thickness of the transparent top layer is not particularly limited, and may be, for example, about 5 μm or more, about 10 μm or more, or about 25 μm or more, and may be about 500 μm or less, about 300 μm or less, or about 200 μm or less. By setting the thickness of the transparent top layer to about 5 μm or more, strength, weather resistance, and chemical resistance may be imparted to the decorative film. By setting the thickness of the transparent top layer to about 500 μm or less, shape-following properties may be imparted to the decorative film. When the transparent top layer has a multilayer structure including a thermoplastic polyurethane elastomer film and another layer (e.g., a topcoat layer), the above thickness refers to the total thickness of the transparent top layer.

[0050] In one embodiment, the thickness of the transparent top layer is about 50 μm or greater. Thickening the transparent top layer allows for a variety of colors (including deep blacks such as piano black) and visual effects to be achieved.

[0051] The painted acrylic pressure-sensitive adhesive layer contains a colorant, which imparts decorativeness and / or concealment to the decorative film. The painted acrylic pressure-sensitive adhesive layer can be formed using a painted adhesive composition containing an adhesive polymer and a colorant. The adhesive polymer can be a (methyl) acrylic polymer. The painted acrylic pressure-sensitive adhesive layer can be crosslinked with a crosslinking agent (such as a bisamide crosslinking agent, an aziridine crosslinking agent, a carbodiimide crosslinking agent, an epoxy crosslinking agent or an isocyanate crosslinking agent).

[0052] Examples of colorants include pigments and dyes. The pigment or dye may be used alone, or two or more thereof may be used in combination. The form of the pigment and dye is not particularly limited, and may be subjected to dispersion treatment.

[0053] Examples of the pigment include inorganic pigments such as titanium oxide, zinc carbonate, zinc oxide, zinc sulfide, calcium carbonate, barium sulfate, talc, kaolin, carbon black, chrome yellow, yellow iron oxide, red iron oxide, red iron oxide, barium sulfate, aluminum oxide, zirconium oxide, iron oxide-based pigments, iron hydroxide-based pigments, chromium oxide-based pigments, spinel-type calcined pigments, chromic acid-based pigments, chrome vermilion-based pigments, iron blue-based pigments, aluminum powder-based pigments, bronze powder-based pigments, and calcium phosphate; and organic pigments such as phthalocyanine-based pigments. The present invention relates to pigments based on phthalocyanine (such as phthalocyanine blue and phthalocyanine green), azo-based pigments, condensed azo-based pigments, azo lake-based pigments, anthraquinone-based pigments, indigo-based pigments, thioindigo-based pigments, isoindolinone-based pigments, azomethine-based pigments, aniline black-based pigments, triphenylmethane-based pigments, perinone-based pigments, perylene-based pigments, quinophthalone-based pigments, dioxazine-based pigments, and quinacridone-based pigments (such as quinacridone red).

[0054] Examples of dyes include azo-based dyes, anthraquinone-based dyes, quinophthalone-based dyes, styryl-based dyes, diphenylmethane-based dyes, triphenylmethane-based dyes, oxazine-based dyes, triazine-based dyes, xanthane-based dyes, azomethine-based dyes, acridine-based dyes, and dioxazine-based dyes.

[0055] The content of the colorant may vary based on the desired decorative properties, concealment, and adhesion of the decorative film, and may, for example, be about 0.1% by mass or more, about 0.5% by mass or more, or about 1% by mass or more, based on the mass of the colored acrylic pressure-sensitive adhesive layer, and may be about 50% by mass or less, about 45% by mass or less, or about 40% by mass or less.

[0056] In the embodiment requiring the decorative film to have concealment, it is preferred that the colorant comprises a white pigment, such as titanium oxide, zinc carbonate, zinc oxide, zinc sulfide, calcium carbonate or barium sulfate, particularly titanium oxide. In this embodiment, the content of the colorant can be about 5% by mass or more, about 10% by mass or more, or about 15% by mass or more based on the mass of the acrylic pressure-sensitive adhesive layer of the coloring, and can be about 50% by mass or less, about 45% by mass or less, or about 40% by mass or less. The acrylic pressure-sensitive adhesive layer of the coloring comprises about 5% by mass to about 50% by mass of white pigment, and this can partially or completely conceal the adherend (bottom layer) surface to which the decorative film is applied.

[0057] In one embodiment, the glass transition temperature (Tg) of the adhesive polymer of the colored acrylic pressure-sensitive adhesive layer is about -40°C or less. By setting the glass transition temperature of the adhesive polymer to about -40°C or less, initial adhesiveness (tackiness) can be effectively imparted to the colored acrylic pressure-sensitive adhesive layer.

[0058] In the case where the binder polymer is a (meth)acrylic polymer, the glass transition temperature of the binder polymer can be determined as a calculated glass transition temperature according to the following Fox formula (Fox T.G., Bull. Am. Phys. Soc., 1 (1956), p. 123), assuming that each polymer is copolymerized with n monomers.

[0059] [Mathematics.1]

[0060]

[0061] In this formula, Tg i represents the glass transition temperature (°C) of the homopolymer of component i, X irepresents the mass fraction of the monomer of component i added during polymerization, and i is a natural number from 1 to n, and

[0062] [Mathematics.2]

[0063]

[0064] In one embodiment, the acrylic pressure-sensitive adhesive layer of coloring contains (meth) acrylic polymers containing carboxyl groups and (meth) acrylic polymers containing amino groups. (meth) acrylic polymers containing carboxyl groups and (meth) acrylic polymers containing amino groups have the ability to stably disperse a large amount of colorants in the acrylic pressure-sensitive adhesive layer of coloring. Therefore, even when the acrylic pressure-sensitive adhesive layer of coloring is relatively thin, the acrylic pressure-sensitive adhesive layer of coloring can also be given decorativeness and / or concealment. From the perspective of the non-flammability of decorative films, the ability to thin the acrylic pressure-sensitive adhesive layer of coloring is advantageous. In addition, (meth) acrylic polymers containing carboxyl groups and (meth) acrylic polymers containing amino groups interact with each other, and the reduction of the cohesive force of the acrylic pressure-sensitive adhesive layer of coloring caused by the dispersion of colorants can be suppressed, and adhesion can be maintained. (meth) acrylic polymers containing carboxyl groups and / or (meth) acrylic polymers containing amino groups can be cross-linked with the above-mentioned cross-linking agent.

[0065] The (meth) acrylic polymer containing a carboxyl group can be obtained by copolymerizing a polymerizable composition comprising a (meth) acrylic monomer and a carboxyl group-containing monomer and a monomer having another monoethylenically unsaturated group as required. In the present disclosure, the (meth) acrylic monomer, the carboxyl group-containing monomer, the amino group-containing monomer and the monomer having another monoethylenically unsaturated group are collectively referred to as polymerizable components. The (meth) acrylic monomer, the carboxyl group-containing monomer and the monomer having another monoethylenically unsaturated group can be used alone or in combination of two or more.

[0066] (Meth) acrylic monomers generally include alkyl (meth) acrylates. The number of carbon atoms of the alkyl group of the alkyl (meth) acrylate may be 1 to 12. Examples of alkyl (meth) acrylates include linear or branched alkyl (meth) acrylates, such as methyl (meth) acrylate, ethyl (meth) acrylate, n-butyl (meth) acrylate, isobutyl (meth) acrylate, 2-methylbutyl (meth) acrylate, isopentyl (meth) acrylate, n-hexyl (meth) acrylate, n-octyl (meth) acrylate, isooctyl (meth) acrylate, 2-ethylhexyl (meth) acrylate, n-nonyl (meth) acrylate, isononyl (meth) acrylate, n-decyl (meth) acrylate, isodecyl (meth) acrylate, and n-dodecyl (meth) acrylate; and alicyclic (meth) acrylates, such as cyclohexyl (meth) acrylate, 4-tert-butylcyclohexyl (meth) acrylate, and isobornyl (meth) acrylate. The alkyl (meth)acrylate preferably includes methyl (meth)acrylate, n-butyl (meth)acrylate, 2-ethylhexyl acrylate, or a combination of these.

[0067] The alkyl (meth)acrylate constitutes the main component of the (meth)acrylic polymer containing a carboxyl group. In one embodiment, the (meth)acrylic polymer containing a carboxyl group is obtained by copolymerizing a polymerizable composition containing the alkyl (meth)acrylate in an amount of about 50% by mass or more, about 70% by mass or more, or about 80% by mass or more, and about 99.5% by mass or less, about 99% by mass or less, or about 98% by mass or less relative to the mass of the polymerizable component, and includes structural units derived from the alkyl (meth)acrylate in the above mass ratios.

[0068] The (meth)acrylic monomer may include aromatic (meth)acrylates such as phenyl (meth)acrylate and p-tolyl (meth)acrylate; phenoxyalkyl (meth)acrylates such as phenoxyethyl (meth)acrylate; alkoxyalkyl (meth)acrylates such as methoxypropyl (meth)acrylate and 2-methoxybutyl (meth)acrylate; or cyclic ether-containing (meth)acrylates such as glycidyl (meth)acrylate or tetrahydrofurfuryl (meth)acrylate.

[0069] Examples of carboxyl group-containing monomers include (meth) acrylic acid, (meth) acrylic acid phthalic acid monohydroxyethyl ester, (meth) acrylic acid β-carboxyethyl ester, 2-(meth) acryloyloxyethyl succinic acid, 2-(meth) acryloyloxyethyl hexahydrophthalic acid, crotonic acid, itaconic acid, fumaric acid, citraconic acid and maleic acid. As the carboxyl group-containing monomer, (meth) acrylic acid is preferred. In the present disclosure, substances corresponding to (meth) acrylic monomers and carboxyl group-containing monomers (such as (meth) acrylic acid) are regarded as carboxyl group-containing monomers.

[0070] In one embodiment, the carboxyl group-containing (meth) acrylic polymer is obtained by copolymerizing a polymerizable composition containing a carboxyl group-containing monomer in an amount of about 0.5 mass % or more, about 1 mass % or more, or about 2 mass % or more, and about 15 mass % or less, about 10 mass % or less, or about 8 mass % or less, relative to the mass of the polymerizable component, and includes structural units derived from the carboxyl group-containing monomer in the above mass ratios.

[0071] Examples of (meth)acrylic monomers or monomers having another monoethylenically unsaturated group include amide group-containing monomers such as (meth)acrylamide, N-vinyl pyrrolidone, and N-vinyl caprolactam; hydroxyl group-containing monomers such as 2-hydroxyethyl (meth)acrylate, 2-hydroxypropyl (meth)acrylate, and 4-hydroxybutyl (meth)acrylate; unsaturated nitriles such as (meth)acrylonitrile; aromatic vinyl monomers such as styrene, α-methylstyrene, and vinyltoluene; and vinyl esters such as vinyl acetate.

[0072] The copolymerization of the (meth) acrylic polymer containing a carboxyl group can be performed by free radical polymerization. As free radical polymerization, known polymerization methods such as solution polymerization, suspension polymerization, emulsion polymerization and bulk polymerization can be used. It is advantageous to use a solution polymerization that can easily synthesize a polymer with a high molecular weight. As a polymerization initiator, for example, an organic peroxide such as benzoyl peroxide, lauroyl peroxide or bis(4-tert-butylcyclohexyl) peroxydicarbonate can be used; or an azo polymerization initiator such as 2,2'-azobisisobutyronitrile, 2,2'-azobis(2-methylbutyronitrile), dimethyl-2,2-azobis(2-methylpropionate), 4,4'-azobis(4-cyanovaleric acid), dimethyl 2,2'-azobis(2-methylpropionate) or azobis(2,4-dimethylvaleronitrile) (AVN) can be used. The polymerization initiator is usually used in an amount of about 0.01 parts by mass or more, or about 0.05 parts by mass or more, and about 5 parts by mass or less, or about 3 parts by mass or less, relative to 100 parts by mass of the polymerizable component.

[0073] The amino group-containing (meth)acrylic polymer increases the cohesive force of the colored acrylic pressure-sensitive adhesive layer by interacting with the carboxyl group-containing (meth)acrylic polymer, and can improve the adhesiveness of the colored acrylic pressure-sensitive adhesive layer.

[0074] The amino group-containing (meth) acrylic polymer can be obtained by copolymerizing a polymerizable composition comprising a (meth) acrylic monomer and an amino group-containing monomer and, as required, a monomer having another monoethylenically unsaturated group. The (meth) acrylic monomer, the amino group-containing monomer, and the monomer having another monoethylenically unsaturated group may be used alone or in combination of two or more.

[0075] As the (meth)acrylic monomer and the monomer having another monoethylenically unsaturated group, the same ones as those described with respect to the carboxyl group-containing (meth)acrylic polymer can be used.

[0076] The alkyl (meth)acrylate constitutes the main component of the (meth)acrylic polymer containing an amino group. In one embodiment, the (meth)acrylic polymer containing an amino group is obtained by copolymerizing a polymerizable composition containing the alkyl (meth)acrylate in an amount of about 50% by mass or more, about 70% by mass or more, or about 80% by mass or more, and about 99.5% by mass or less, about 99% by mass or less, or about 98% by mass or less relative to the mass of the polymerizable component, and includes structural units derived from the alkyl (meth)acrylate in the above mass ratios.

[0077] Examples of amino group-containing monomers include aminoalkyl (meth)acrylates, such as aminoethyl (meth)acrylate; monoalkylaminoalkyl (meth)acrylates, such as butylaminoethyl (meth)acrylate; dialkylaminoalkyl (meth)acrylates, such as N,N-dimethylaminoethyl acrylate (DMAEA) and N,N-dimethylaminoethyl methacrylate (DMAEMA); dialkylaminoalkyl (meth)acrylamides, such as N,N-dimethylaminopropyl acrylamide (DMAPAA) and N,N-dimethylaminopropyl methacrylamide; and dialkylaminoalkyl vinyl ethers, such as N,N-dimethylaminoethyl vinyl ether and N,N-diethylaminoethyl vinyl ether. As the amino group-containing monomer, preferred is dialkylaminoalkyl (meth)acrylate, such as N,N-dimethylaminoethyl acrylate (DMAEA) or N,N-dimethylaminoethyl methacrylate (DMAEMA). In the present disclosure, a substance corresponding to a (meth)acrylic monomer and an amino group-containing monomer, such as aminoethyl (meth)acrylate, is regarded as an amino group-containing monomer.

[0078] In one embodiment, the amino group-containing (meth)acrylic polymer is obtained by copolymerizing a polymerizable composition containing an amino group-containing monomer in an amount of about 0.5 mass % or more, about 1 mass % or more, or about 2 mass % or more, and about 20 mass % or less, about 15 mass % or less, or about 10 mass % or less, relative to the mass of the polymerizable component, and includes structural units derived from the amino group-containing monomer in the above mass ratios.

[0079] The amino group-containing (meth) acrylic polymer is preferably an amino group-containing (meth) acrylic polymer not containing a monomer unit derived from an aromatic vinyl monomer (hereinafter also referred to as "amino group-containing non-aromatic (meth) acrylic polymer" in the present disclosure). The amino group-containing non-aromatic (meth) acrylic polymer has excellent miscibility with the carboxyl group-containing (meth) acrylic polymer, and thus can make the interaction with the carboxyl group-containing (meth) acrylic polymer more effective.

[0080] The non-aromatic (meth) acrylic polymer containing an amino group does not contain a structural unit derived from an aromatic vinyl monomer. Examples of aromatic vinyl monomers include (meth) acrylamides of styrene, α-methylstyrene, vinyl toluene, vinyl naphthalene, vinyl anthracene, vinyl anthraquinone, aromatic amines, and (meth) acrylic esters of aromatic compounds containing hydroxyl groups. Examples of aromatic amines include aniline, benzylamine, naphthylamine, aminoanthracene, aminoanthraquinone, and derivatives thereof. Examples of aromatic compounds containing hydroxyl groups include compounds containing hydroxyl groups corresponding to the aromatic amines described above.

[0081] The copolymerization of the (meth) acrylic polymer containing an amino group can be carried out by free radical polymerization in the same manner as the copolymerization of the (meth) acrylic polymer containing a carboxyl group. The polymerization method, polymerization initiator and the amount thereof used are the same as those described for the copolymerization of the (meth) acrylic polymer containing a carboxyl group.

[0082] In the colored acrylic pressure-sensitive adhesive layer, at least one of a carboxyl group-containing (meth) acrylic polymer or an amino group-containing (meth) acrylic polymer is used as an acrylic adhesive polymer. The acrylic adhesive polymer imparts pressure-sensitive adhesive properties to the colored acrylic pressure-sensitive adhesive layer at an operating temperature (e.g., 5° C. to 35° C.).

[0083] The glass transition temperature (Tg) of the acrylic adhesive polymer may be from about -70°C to about -40°C. In one embodiment, the glass transition temperature of the acrylic adhesive polymer is about -65°C or higher or about -60°C or higher, and about -45°C or lower or about -50°C or lower. By setting the glass transition temperature of the acrylic adhesive polymer to about -70°C or higher, the colored acrylic pressure-sensitive adhesive layer can be given adhesive strength and holding strength. By setting the glass transition temperature of the acrylic adhesive polymer to about -40°C or lower, the colored acrylic pressure-sensitive adhesive layer can be effectively given initial adhesion (tack). The glass transition temperature (Tg) of the acrylic adhesive polymer can be determined as the calculated glass transition temperature by using the above-mentioned Fox formula.

[0084] In one embodiment, the acrylic adhesive polymer has a weight average molecular weight (Mw) of about 150,000 or more, about 200,000 or more, or about 250,000 or more, and about 2,000,000 or less, about 1,500,000 or less, or about 1,000,000 or less.

[0085] The mass ratio of the (meth)acrylic polymer containing a carboxyl group to the (meth)acrylic polymer containing an amino group is 100: about 0.1 to 50, 100: about 1 to 40 or 100: about 2 to 30 (when the (meth)acrylic polymer containing a carboxyl group is used as the acrylic adhesive polymer), or about 0.1 to 50:100, about 1 to 40:100 or about 2 to 30:100 (when the (meth)acrylic polymer containing an amino group is used as the acrylic adhesive polymer).

[0086] In one embodiment, another (meth) acrylic polymer different from the (meth) acrylic polymer used as the acrylic adhesive polymer can be used as an acrylic polymer additive. That is, in the case where a (meth) acrylic polymer containing a carboxyl group is used as the acrylic adhesive polymer, a (meth) acrylic polymer containing an amino group can be used as an acrylic polymer additive, and in the case where a (meth) acrylic polymer containing an amino group is used as the acrylic adhesive polymer, a (meth) acrylic polymer containing a carboxyl group can be used as an acrylic polymer additive. By interacting with the acid (carboxyl group)-base (amino group) of the acrylic adhesive polymer, the acrylic polymer additive can suppress the reduction of cohesive force caused by the depolymerization of the acrylic adhesive polymer caused by exposure to sunlight, etc., and the adhesive strength of the colored acrylic pressure-sensitive adhesive layer can be maintained at a desired level.

[0087] In one embodiment, the (meth)acrylic polymer containing a carboxyl group is an acrylic adhesive polymer, and the (meth)acrylic polymer containing an amino group is an acrylic polymer additive.

[0088] The glass transition temperature (Tg) of the acrylic polymer additive may be from about 20°C to about 120°C. In one embodiment, the glass transition temperature of the acrylic polymer additive is about 30°C or higher or about 45°C or higher, and about 100°C or lower or about 80°C or lower. By setting the glass transition temperature of the acrylic polymer additive to about 20°C or higher, the reduction in cohesive force caused by the depolymerization of the acrylic adhesive polymer due to exposure to sunlight, etc. can be suppressed, and the adhesive strength of the colored acrylic pressure-sensitive adhesive layer can be maintained at a desired level. By setting the glass transition temperature of the acrylic polymer additive to about 120°C or lower, adhesion within a normal temperature range can be ensured. The glass transition temperature of the acrylic polymer additive can be determined by using a Fox formula similar to that of the acrylic adhesive polymer.

[0089] In one embodiment, the acrylic polymer additive has a weight average molecular weight (Mw) of about 1,000 or greater, about 5,000 or greater, or about 10,000 or greater, and about 200,000 or less, about 100,000 or less, or about 80,000 or less.

[0090] At least one of the (meth) acrylic polymer containing carboxyl groups and the (meth) acrylic polymer containing amino groups can be used as the dispersant of coloring agent. In this embodiment, premix (also referred to as grinding base) can be prepared by mixing coloring agent with the (meth) acrylic polymer used as dispersant, and the gained premix can be mixed with other components of the adhesive composition of the coloring that is used to form the acrylic pressure-sensitive adhesive layer of coloring. Therefore, a large amount of coloring agents can be stably dispersed in the acrylic pressure-sensitive adhesive layer of coloring. Prepare premix for each coloring agent in a variety of coloring agents, these premixes are suitably mixed, thereby also can promote color matching.

[0091] The carboxyl group-containing (meth) acrylic polymer or amino group-containing (meth) acrylic polymer used as a dispersant may be the same as or different from the substance used as an acrylic adhesive polymer or an acrylic polymer additive. In the latter case, the colored acrylic pressure-sensitive adhesive layer contains two or more carboxyl group-containing (meth) acrylic polymers or amino group-containing (meth) acrylic polymers, that is, a carboxyl group-containing (meth) acrylic polymer or amino group-containing (meth) acrylic polymer used as a dispersant, and a carboxyl group-containing (meth) acrylic polymer or amino group-containing (meth) acrylic polymer used as an acrylic adhesive polymer or an acrylic polymer additive.

[0092] The weight average molecular weight (Mw) of the carboxyl group-containing (meth)acrylic polymer or the amino group-containing (meth)acrylic polymer used as the dispersant may generally be about 1,000 or more or about 10,000 or more, and about 1,500,000 or less or about 800,000 or less.

[0093] By using a colored adhesive composition containing a carboxyl group-containing (meth) acrylic polymer, an amino group-containing (meth) acrylic polymer and a colorant, and, if necessary, a cross-linking agent, a solvent and / or other additives, a colored acrylic pressure-sensitive adhesive layer can be formed on a transparent thermoplastic polyurethane elastomer film of a transparent top layer or liner.

[0094] Before the preparation of the colored adhesive composition, premix can be prepared by mixing coloring agent, (methyl) acrylic polymer containing carboxyl group as dispersant or (methyl) acrylic polymer containing amino group.Can be mixed by using for example paint stirrer, sand mill, ball mill, vertical mill or three-roll mill.When mixing, water-based solvent or organic solvent can be added as required.Gained premix is ​​mixed with the additional components of the colored adhesive composition, and the colored adhesive composition can be prepared.When using multiple coloring agents, every kind of premix can be prepared for every kind of coloring agent, then the color can be adjusted by appropriately mixing these premixes, and the premix mixture can be mixed with other components of the colored adhesive composition.

[0095] The mass ratio of the total amount of the colorant to the amount of the dispersant may be about 1 to 100: about 5 to 1000, about 1 to 100: about 10 to 700, or about 1 to 100: about 10 to 500. The entire amount of the dispersant may be used during the preparation of the premix, or a portion of the dispersant may be used during the preparation of the premix and the remaining dispersant may be used during the preparation of the colored adhesive composition.

[0096] The crosslinking agent is not particularly limited as long as the crosslinking agent can form crosslinks between polymer chains of the carboxyl group-containing (meth) acrylic polymer or the amino group-containing (meth) acrylic polymer. For example, as the crosslinking agent of the carboxyl group-containing (meth) acrylic polymer, an epoxy crosslinking agent, a bisamide crosslinking agent, an aziridine crosslinking agent, a carbodiimide crosslinking agent or an isocyanate crosslinking agent can be used.

[0097] Examples of epoxy crosslinking agents include N,N,N',N'-tetraglycidyl-1,3-phenylenedi(methylamine) (trade name: TETRAD-X (Mitsubishi Gas Chemical Company Inc., Chiyoda-ku, Tokyo, Japan), E-AX and E-5XM (all from Soken Chemical & Engineering Co., Ltd., Toshima-ku, Tokyo, Japan)); and N,N'-(cyclohexane-1,3-diylbismethylene)bis(diglycidylamine) (trade name: TETRAD-C (Mitsubishi Gas Chemical Company Inc., Chiyoda-ku, Tokyo, Japan) and E-5C (Soken Chemical & Engineering Co., Ltd., Toshima-ku, Tokyo, Japan). Co.,Ltd.,Toshima-ku,Tokyo,Japan))).

[0098] Examples of the bisamide crosslinking agent include 1,1′-isophthalyl-bis(2-propyleneimide), 1,4-bis(vinyliminocarbonylamino)benzene, 4,4′-bis(vinyliminocarbonylamino)diphenylmethane, and 1,8-bis(vinyliminocarbonylamino)octane.

[0099] Examples of aziridine crosslinking agents include 2,2-bis(hydroxymethyl)butanol-tris[3-(1-aziridinyl)propionate (trade name: CHEMITITE (trade name) PZ-33 (Nippon Shokubai Co., Ltd. Osaka-shi, Osaka, Japan)) and crosslinker CX-100 (DSM Coating Resins BV Zwolle, Netherlands).

[0100] Examples of carbodiimide crosslinkers include Carbodilite V-03, V-05, and V-07 (all from Nisshinbo Chemical Inc. Chuo-ku, Tokyo, Japan).

[0101] Examples of isocyanate crosslinking agents include Coronate L and Coronate HK (both available from Tosoh Corporation Minato-ku, Tokyo, Japan).

[0102] The crosslinking agent may be used in an amount of about 0.01 parts by mass or more, about 0.02 parts by mass or more, or about 0.05 parts by mass or more, and about 0.5 parts by mass or less, about 0.4 parts by mass or less, or about 0.3 parts by mass or less, based on 100 parts by mass of the carboxyl group-containing (meth)acrylic polymer or the amino group-containing (meth)acrylic polymer used as the acrylic binder polymer.

[0103] Examples of the solvent include methanol, ethanol, hexane, heptane, toluene, acetone, methyl ethyl ketone, methyl isobutyl ketone, ethyl acetate, butyl acetate, and mixed solvents thereof.

[0104] Examples of other additives include UV absorbers, antioxidants, heat stabilizers, fillers, and tackifiers.

[0105] In one embodiment, the colored acrylic pressure-sensitive adhesive layer is substantially free of flame retardants. Here, "substantially free of" means that the content of flame retardants is less than about 1% by mass, less than about 0.5% by mass or less than about 0.2% by mass based on the mass of the colored acrylic pressure-sensitive adhesive layer. The example of flame retardant includes organic flame retardants, such as bromine-based flame retardants, phosphorus-based flame retardants and chlorine-based flame retardants; and inorganic flame retardants, such as antimony compounds, metal hydroxides, nitrogen compounds and boron compounds. The colored acrylic pressure-sensitive adhesive layer substantially free of flame retardants will not cause a reduction in bonding strength or will not turn yellow due to the migration of flame retardants, so the bonding strength and appearance of the decorative film can be maintained for a long time. In the present disclosure, pigments (such as titanium oxide) are not included in the content of flame retardants.

[0106] The thickness of the colored acrylic pressure-sensitive adhesive layer may vary based on the decorativeness, concealment, and adhesion required for the decorative film, and may be, for example, about 5 μm or more, about 10 μm or more, or about 15 μm or more, and may be about 100 μm or less, about 80 μm or less, or about 50 μm or less. From the perspective of the non-flammability of the decorative film, the thickness of the colored acrylic pressure-sensitive adhesive layer is preferably about 80 μm or less, and more preferably about 50 μm or less.

[0107] Decorative film can be produced by known methods. For example, use a knife coater, a bar coater, etc. to apply the colored adhesive composition to the liner and dry to form a colored acrylic pressure-sensitive adhesive layer. In order to allow the reaction of the cross-linking agent as an optional component to proceed, the colored acrylic pressure-sensitive adhesive layer can be heated by hot air or an oven during drying. By methods such as dry lamination, a transparent top layer is stacked on the colored acrylic pressure-sensitive adhesive layer of the gained, so that the thermoplastic polyurethane elastomer film of the transparent top layer contacts with the colored acrylic pressure-sensitive adhesive layer, thereby forming a decorative film. Decorative film can also be produced by directly applying the colored adhesive composition to the thermoplastic polyurethane elastomer film of the transparent top layer and drying.

[0108] The decorative film may include a liner on the surface of the colored acrylic pressure-sensitive adhesive layer, which is on the opposite side of the transparent top layer. Examples of liners as optional components include plastic materials such as polyethylene, polypropylene, polyester and cellulose acetate, paper and laminated paper of plastic materials. These liners may have a surface treated with a release liner such as silicone. The thickness of the liner may generally be about 10 μm or more or about 25 μm or more, and about 500 μm or less or about 200 μm or less.

[0109] Painted acrylic pressure-sensitive adhesive layer can be solid, also can be porous body or foam.The adhesive surface of painted acrylic pressure-sensitive adhesive layer can be flat or can have depression and projection.The adhesive surface with groove and projection comprises the adhesive surface (forming therein the projection of the solid component of the solid component of the adhesive composition that comprises painted or reaction product and around the groove of this projection) of painted acrylic pressure-sensitive adhesive layer, and when adhesive surface is attached to adherend, between adherend surface and adhesive surface, form communication channel, this communication channel is limited by groove and is communicated with the external space.The example of the method for forming this adhesive surface with groove and projection will be described below.

[0110] Preparation has the liner of stripping surface, and this stripping surface comprises predetermined groove and convex structure.The painted adhesive composition is applied to the stripping surface of liner, and heats as required, thereby forms painted acrylic pressure-sensitive adhesive layer.Therefore, the groove of liner and convex structure (negative structure) are transferred to the surface of painted acrylic pressure-sensitive adhesive layer, and this surface contacts (adhesive surface as the decorative film) with liner, thereby forms the adhesive surface with the groove that comprises predetermined structure (positive structure) and convex.As mentioned above, the groove and the projection of adhesive surface are designed to comprise groove in advance, and this groove allows to form communication passage when projection is attached to adherend.

[0111] For the groove of the acrylic pressure-sensitive adhesive layer of coloring, the groove with a consistent shape can be arranged at the adhesive surface to form a regular patterned groove according to a regular pattern, or the groove with an undetermined shape can be arranged to form an irregular patterned groove. In the case where a plurality of grooves are formed to be arranged substantially parallel to each other, the interval of the groove is preferably about 10 μm or larger or about 100 μm or larger, and about 2000 μm or smaller or about 1000 μm or smaller. The depth of the groove (the distance from the adhesive surface to the bottom of the groove measured toward the transparent top layer) is generally about 10 μm or larger and about 100 μm or smaller. The shape of the groove is not particularly limited either, as long as the effect of the present invention is not compromised. For example, at the cross section of the groove perpendicular to the direction of the adhesive surface, the shape of the groove can be roughly rectangular (including trapezoidal), roughly semicircular or roughly semi-elliptical.

[0112] In one embodiment, the transparent top layer and the colored acrylic pressure-sensitive adhesive layer are disposed adjacent to each other. In other words, in this embodiment, no other layer (e.g., a printed layer) is interposed between the transparent top layer and the colored acrylic pressure-sensitive adhesive layer. When the transparent top layer and the colored acrylic pressure-sensitive adhesive layer are disposed adjacent to each other, the hue, brightness, and saturation of the colored acrylic pressure-sensitive adhesive layer visually recognized in the state of the decorative film are only affected by the transparent top layer, and are not affected by other factors. Therefore, in this embodiment, the hue of the colored acrylic pressure-sensitive adhesive layer can be easily adjusted.

[0113] The thickness of the decorative film may be about 30 μm or more, about 50 μm or more, or about 70 μm or more, but may be about 1 mm or less, about 500 μm or less, or about 300 μm or less. The thickness of the decorative film does not include the thickness of the liner. In the case where the decorative film is required to be chip resistant, the thickness of the decorative film is preferably about 100 μm or more, and more preferably about 120 μm or more.

[0114] In one embodiment, the thickness of the decorative film is about 240 μm or less. A decorative film having a thickness of about 240 μm or less can impart flame retardancy required for the decorative film. The thickness of the decorative film required to have flame retardancy is preferably about 200 μm or less, and more preferably about 180 μm or less.

[0115] In one embodiment, the tensile strength of the decorative film at 2% strain is about 20N / 25mm or less, about 15N / 25mm or less, or about 10N / 25mm or less. The tensile strength of the decorative film at 2% strain is not particularly limited and may be about 0.5N / 25mm or greater, about 1N / 25mm or greater, or about 1.5N / 25mm or greater. The tensile strength of the decorative film at 2% strain is determined by the method described in the Examples.

[0116] In one embodiment, the elongation of the decorative film is about 150% or more, about 200% or more, or about 300% or more. A decorative film having an elongation of about 150% or more has high elasticity and excellent flexibility, and thus has excellent resistance to chipping. The elongation of the decorative film is not particularly limited, and may be about 1000% or less, about 800% or less, or about 600% or less. According to this embodiment, the elongation of the decorative film is determined by the method described in the examples.

[0117] In one embodiment, the elongation of the decorative film measured according to JIS A 5759:2016 6.8 is 60% or more, and the breaking strength is 50 N / 25 mm or more. The decorative film having the elongation and the breaking strength can be suitably used for preventing glass scattering.

[0118] The decorative film preferably effectively conceals the color or pattern of the surface of the adherend (bottom layer), for example. In the decorative film of the embodiment, when the color difference ΔE is measured from one side of the transparent top layer when the background color is white and black, * When the color difference ΔE between a part of the white background color and a part of the black background color is * 11 or less. Color difference ΔE * A decorative film having a color difference of 11 or less has excellent concealment of the base layer and can be suitably used for a car film. * Determined by using a spectrophotometer according to the procedure described in the "Hiding Ability" section of the Examples.

[0119] As measured according to ISO 5660-1 heat release rate (cone calorimeter method), the decorative film of the embodiment has a heat release rate of 8 MJ / m 20 minutes after the start of heating. 2 The total heat release is preferably about 7 MJ / m 2or less, or more preferably about 6 MJ / m 2 or less. will have 8MJ / m 2 Decorative films having a total heat release of 0.1 % or less are evaluated as non-flammable.

[0120] In one embodiment, the decorative film is substantially free of flame retardants. It should be noted that "substantially free" means that the content of flame retardants is about less than 1 mass%, about less than 0.5 mass%, or about less than 0.2 mass% relative to the mass of the decorative film. Examples of flame retardants include organic flame retardants, such as bromine-based flame retardants, phosphorus-based flame retardants, and chlorine-based flame retardants; and inorganic flame retardants, such as antimony compounds, metal hydroxides, nitrogen compounds, and boron compounds. In the present disclosure, pigments (such as titanium oxide) that can be used as flame retardants are not included in the content of flame retardants.

[0121] In one embodiment, the decorative film is a non-PVC based decorative film.

[0122] The decorative film of the present disclosure can be used for external purposes, such as vehicles, such as railways and ships; and exterior walls, such as those of buildings, storage tanks and transformer facilities. In particular, the decorative film of the present disclosure has excellent elongation, so it can be suitable for use as a colored film for automobile film and an anti-scattering film. The decorative film of the present disclosure can also be suitable for the decoration of interior illuminated signs.

[0123] Example

[0124] In the following examples, specific embodiments of the present disclosure will be illustrated, but the present invention is not limited to these embodiments. Unless otherwise specified, all "parts" and "percents" are by mass.

[0125] The raw materials used to prepare the decorative films are shown in Table 1.

[0126]

[0127] Pigments 1 to 4 used to produce the decorative films are shown in Table 2.

[0128] Table 2

[0129]

[0130] The compositions of Millbase 1 to Millbase 4 (premixes) used to prepare decorative films are shown in Table 3.

[0131] Table 3

[0132]

[0133] The compositions of the colored adhesive compositions CA1 to CA3 used to prepare the decorative films are shown in Table 4. The colored adhesive compositions CA1 to CA3 were prepared by mixing mill base 1 to mill base 4 and other raw materials.

[0134] Table 4 (values ​​are in wet mass %)

[0135]

[0136]

[0137] Example 1 to Example 3

[0138] Crosslinking agent 1 (CL1) was mixed in each colored adhesive composition shown in Table 5. The mass ratio of ADH1 and CL1 was 100:0.5 in terms of solid content. Each colored adhesive composition was applied to a liner with a structured surface (SCW860DNL, 3M Japan Limited, Shinagawa-ku, Tokyo, Japan) using a knife coater and dried at 95°C for 3 minutes. After drying, a pressure-sensitive adhesive layer with a thickness of 25 μm was obtained. Each pressure-sensitive adhesive layer was bonded to a thermoplastic polyurethane film 1 (TPU1), and the polyester support film was peeled off from the surface of TPU1 to obtain the decorative films of Examples 1 to 3.

[0139] Reference Example 1

[0140] 3M (trade name) Scotchgard (trade name) Paint Protection Film Pro Series SGH6PRO4 (3M Japan Limited, Shinagawa-ku, Tokyo, Japan).

[0141] Comparative Example 1

[0142] PVC-based 3M (trade name) Scotchcal (registered trademark) Film JS1236XL (3M Japan Limited, Shinagawa-ku, Tokyo, Japan).

[0143] Comparative Example 2

[0144] PVC-based 3M (trade name) Scotchcal (trade name) Film JS6217XL (3M Japan Limited, Shinagawa-ku, Tokyo, Japan).

[0145] The decorative films were evaluated for the following items.

[0146] Breaking strength

[0147] The test piece was prepared by cutting the decorative film into a width of 25 mm and a length of 150 mm. The tensile strength at the breaking point at 20° C. was measured using a tensile tester (Teng Xilong Universal Testing Machine, Model: RTC-1210A, manufactured by A&D Company, Limited, Toshima-ku, Tokyo, Japan) at 20° C., a distance between the grippers of 100 mm, and a tensile speed of 300 mm / min.

[0148] Elongation

[0149] The test piece was prepared by cutting the decorative film into a width of 25 mm and a length of 150 mm. The elongation at 20° C. was measured using a tensile tester (Teng Xilong Universal Testing Machine, Model: RTC-1210A, manufactured by A&D Company, Limited, Toshima-ku, Tokyo, Japan) at 20° C., a distance between the grippers of 100 mm, and a tensile speed of 300 mm / min. The elongation is defined by the following equation.

[0150] Elongation (%) = (length of the test piece after the test - length of the test piece before the test) / length of the test piece before the test Tensile strength at 2% strain

[0151] The test piece was prepared by cutting the decorative film into a width of 25 mm and a length of 150 mm. The tensile strength at 2% strain at 20° C. was measured using a tensile tester (Teng Xilong Universal Testing Machine, Model: RTC-1210A, manufactured by A&D Company, Limited, Toshima-ku, Tokyo, Japan) at 20° C., a distance between the grippers of 100 mm, and a tensile speed of 300 mm / min.

[0152] Adhesion

[0153] The test piece is prepared by cutting the decorative film into a width of 25 mm and a length of 150 mm. The test piece is adhered to an aluminum plate (Paltek Corporation, Hiratsuka-shi, Kanagawa, Japan) using a roller at 20°C. The adhesion method is according to JIS Z 0237:2009 8.2.3. The test piece is kept at 20°C for 48 hours. Using a tensile tester (Teng Xilong universal testing machine, model: RTC-1210A, manufactured by A&D Co., Ltd., Toshima-ku, Tokyo, Japan), the adhesive force when 180 degrees of peeling is measured at a peeling rate of 300 mm / min at 20°C.

[0154] Heat shrink

[0155] The test piece was prepared by cutting the decorative film into a width of 50 mm and a length of 100 mm. The test piece was adhered to an aluminum plate A5052P (Paltek Corporation, Hiratsuka-shi, Kanagawa, Japan) by a roller in an environment of 23°C and placed in an environment of 23°C for 24 hours. On the test piece, a cross was cut with a utility knife. The test piece was then heated at 65°C for 48 hours. After heat aging, the shrinkage (mm) of the film was measured by a microscope, and the maximum value was recorded.

[0156] Concealment

[0157] The test piece was prepared by cutting the decorative film into a square with a side length of 50 mm. The test piece was adhered to the hiding ability chart (inspection item, hiding ability chart, SEIEIDO Printing Co., Ltd., Yonezawa-shi, Yamagata, Japan). For the white area and the black area, the L of the test piece was measured by using a spectrophotometer (CM-3700d, Konica Minolta Japan, Inc., Minato-ku, Tokyo, Japan) * 、a * and b * The measurement value of the white area is determined by L1 * 、a1 * and b1 * Indicated by L2, and the measurement value of the black area is * 、a2 *and b2 * When expressed, the color difference ΔE as a concealment capability indicator is calculated and determined by the following formula * :

[0158] ΔE * =[(L2 * -L1 * ) 2 +(a2 * -a1 * ) 2 +(b2 * -b1 * ) 2 ] 1 / 2 .

[0159] Transmittance

[0160] The test piece was prepared by cutting TPU1 into a square with a side length of 50 mm. The total light transmittance, haze, diffuse transmittance and parallel transmittance of the test piece were measured using a haze meter (HM-150, MURAKAMI COLOR RESEARCH LABORATORY, Chuo-ku, Tokyo, Japan). The measurement was performed according to JIS K7136:2000. The average value of three measurements was recorded as a representative measurement value. The total light transmittance of TPU1 was 91.3%, and the haze was 83.4.

[0161] The compositions and evaluation results of the decorative films of Examples 1 to 3, Reference Example 1, and Comparative Examples 1 and 2 are shown in Table 5. Figure 2 In the figure, the relationship between the elongation (%) and the tensile strength (N / 25 mm) of the decorative films of Examples 1 to 3 and Reference Example 1 is shown as a graph.

[0162]

[0163] Without departing from the basic principles of the present invention, various modifications of the above embodiments and embodiments will be apparent to those skilled in the art. It will also be apparent to those skilled in the art that various improvements and modifications may be made to the present invention without departing from the spirit and scope of the present invention. Some embodiments of the present disclosure are described below.

[0164] First aspect

[0165] A decorative film comprising: a transparent top layer comprising a transparent thermoplastic polyurethane elastomer film; and a colored acrylic pressure-sensitive adhesive layer, wherein the decorative film has a tensile strength of 20 N / 25 mm or less at 2% strain and an elongation of 150% or more.

[0166] Second aspect

[0167] According to the decorative film of the first aspect, wherein the transparent top layer has a total light transmittance of 80% or more in the wavelength range of 380 nm to 780 nm.

[0168] The third aspect

[0169] The decorative film according to the first aspect or the second aspect, wherein the transparent top layer and the colored acrylic pressure-sensitive adhesive layer are disposed adjacent to each other.

[0170] The fourth aspect

[0171] The decorative film according to any one of the first to third aspects, wherein the elongation of the decorative film measured according to JIS A5759:2016 6.8 is 60% or more, and the breaking strength is 50 N / 25 mm or more.

[0172] Fifth Aspect

[0173] The decorative film according to any one of the first to fourth aspects, wherein the colored acrylic pressure-sensitive adhesive layer comprises an adhesive polymer having a glass transition temperature of -40°C or less.

[0174] The sixth aspect

[0175] The decorative film according to any one of the first to fifth aspects, wherein the colored acrylic pressure-sensitive adhesive layer contains a carboxyl group-containing (meth)acrylic polymer and an amino group-containing (meth)acrylic polymer.

[0176] Seventh Aspect

[0177] The decorative film according to any one of the first to sixth aspects, wherein the transparent top layer comprises a topcoat layer on the opposite side of the transparent thermoplastic polyurethane elastomer film from the colored acrylic pressure-sensitive adhesive layer.

[0178] Eighth Aspect

[0179] The decorative film according to any one of the first to seventh aspects, wherein a thickness of the decorative film is 240 μm or less.

[0180] Ninth Aspect

[0181] The decorative film according to any one of the first to eighth aspects, wherein the total heat release 20 minutes after the start of heating measured according to ISO 5660-1 heat release rate (cone calorimeter method) is 8 MJ / m 2 or less.

[0182] Tenth Aspect

[0183] The decorative film according to any one of the first to ninth aspects, wherein the decorative film is substantially free of flame retardants.

[0184] Aspect 11

[0185] The decorative film according to any one of the first to tenth aspects, wherein the color difference ΔE is measured from one side of the transparent top layer when the background color is white and black. * When the color difference ΔE between a part of the white background color and a part of the black background color is * is 11 or less.

Claims

1. A decorative film, comprising: a transparent top layer, the transparent top layer comprising a transparent thermoplastic polyurethane elastomer film; as well as A pigmented acrylic pressure-sensitive adhesive layer, wherein The decorative film has a tensile strength of 20 N / 25 mm or less at 2% strain and an elongation of 150% or more.

2. The decorative film according to claim 1, wherein The transparent top layer has a total light transmittance of 80% or more in the wavelength range of 380 nm to 780 nm.

3. The decorative film according to claim 1 or 2, wherein: The transparent top layer and the pigmented acrylic pressure sensitive adhesive layer are disposed adjacent to each other. 4 . The decorative film according to claim 1 , which has an elongation of 60% or more and a breaking strength of 50 N / 25 mm or more as measured according to JIS A 5759:2016 6.

8.

5. The decorative film according to claim 1 or 2, wherein: The colored acrylic pressure-sensitive adhesive layer includes an adhesive polymer having a glass transition temperature of -40°C or less.

6. The decorative film according to claim 1 or 2, wherein: The colored acrylic pressure-sensitive adhesive layer contains a carboxyl group-containing (meth)acrylic polymer and an amino group-containing (meth)acrylic polymer.

7. The decorative film according to claim 1 or 2, wherein: The transparent top layer includes a topcoat layer on the opposite side of the transparent thermoplastic polyurethane elastomer film from the pigmented acrylic pressure-sensitive adhesive layer. 8 . The decorative film according to claim 1 , wherein the thickness of the decorative film is 240 μm or less.

9. The decorative film according to claim 1 or 2, wherein: The total heat release 20 minutes after the start of heating measured according to ISO 5660-1 heat release rate (cone calorimeter method) is 8 MJ / m2 or less.

10. The decorative film of claim 1 or 2, wherein the decorative film is substantially free of flame retardants.

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