Laminate excellent in weather resistance and, transfer film for obtaining the laminate

Abstract

To provide a laminate having excellent metallic luster and excellent in weather resistance, and a transfer film for obtaining the same.SOLUTION: A transfer film 10 in which at least a release layer 2, an intermediate layer 3, a vapor-deposited base layer 4, a metal vapor-deposited layer 5, and an adhesive layer 6 are arranged on a release substrate in this order, wherein the release layer, the intermediate layer, and the metal base layer are all composed of at least a reaction cured product of a polyol and a polyisocyanate, and satisfy the following conditions A) to C): A) The polyisocyanate constituting the release layer comprises one or more selected from aliphatic or alicyclic isocyanates, or a combination thereof. B) The polyisocyanate constituting the intermediate layer comprises one or more selected from aliphatic, alicyclic, or aromatic aliphatic isocyanates, or a combination thereof. C) The polyisocyanate constituting the metal base layer comprises an aromatic isocyanate.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a laminate having excellent weather resistance and a transfer film for obtaining the laminate. [Background technology]

[0002] Conventionally, a method has been widely used in which a transfer film is used in which a release layer, a functional layer (protective layer, colored layer, printing layer, hard coat layer, anti-reflection layer, metal vapor deposition layer, etc.), and an adhesive layer are sequentially formed on a plastic film, and the functional layer and adhesive layer (hereinafter, these layers are collectively referred to as transfer layers) formed on the release layer of the transfer film are transferred to the surface of an object to be transferred, thereby forming a transfer layer on the surface of the object to be transferred, thereby obtaining a laminate that is endowed with various functions such as design properties such as metallic luster and patterns, hard coat properties, and anti-reflection properties. The laminates are used in a variety of products such as home appliances, automobile parts, miscellaneous goods, paper containers, labels, etc.

[0003] When a laminate is applied to the exterior of an automobile, surface properties, particularly weather resistance, that is, properties that do not cause deterioration such as yellowing, deterioration in gloss (decrease in glossiness), or changes in appearance (foaming, peeling, cracking, etc.) even when exposed to external light including ultraviolet rays or changes in temperature and humidity for a long period of time, are considered important.

[0004] Patent Document 1 discloses a design transfer sheet (transfer film) including a design transfer layer formed releasably on a release layer as a transfer sheet (transfer film) for obtaining a laminate having a decorated surface. Patent Document 2 also discloses a thermal transfer film (transfer film) for easily forming a surface protection layer having excellent weather resistance, transparency, and hard coat properties on a transfer target (substrate to be decorated) by thermal transfer, and a method for producing the thermal transfer film (transfer film) by incorporating an ionizing radiation-curable resin composition and setting the exposure dose of ionizing radiation within a specific range. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] Japanese Patent Application Laid-Open No. 2016-120643 [Patent Document 2] Japanese Patent Application Laid-Open No. 2014-198317 Summary of the Invention [Problem to be solved by the invention]

[0006] When the laminate is used for automobile exterior parts, such as a front grille, weather resistance and at the same time design properties such as metallic luster derived from the metal vapor deposition layer are required. Conventionally known transfer films such as those described in Patent Documents 1 and 2 have insufficient weather resistance, and have had problems such as deterioration of metallic luster, yellowing, and changes in appearance due to ultraviolet rays, high temperatures, and high humidity. Specifically, when a conventional laminate using a transfer film with a metal vapor deposition layer is provided with only a layer made of a resin that easily absorbs UV rays (e.g., a reaction-cured product using an isocyanate having an aromatic ring) on ​​the surface side of the laminate (on the metal vapor deposition layer), the resin constituting the resin layer absorbs UV energy, oxidizes, and forms a quinone structure, which can cause the resin layer, and ultimately the entire laminate, to appear yellowed. Conversely, when only a layer made of a resin that does not easily absorb UV rays (e.g., a reaction-cured product using an isocyanate having no aromatic ring) is provided on the surface side of the laminate (on the metal vapor deposition layer), UV rays penetrate through pinholes, which are unavoidably present in the metal vapor deposition layer, or through the sea portion of the sea-island structure of the metal vapor deposition layer where no metal vapor deposition layer is present, causing deterioration of the adhesive layer and the substrate to be decorated. As a result, problems such as deterioration of the metallic luster and changes in appearance have occurred. Furthermore, a layer made of a reaction cured product using an alicyclic or aliphatic isocyanate may have poor heat resistance, and it may be difficult to obtain the desired metallic luster when forming a metal vapor deposition layer. Furthermore, when additives such as ultraviolet absorbers are added to the resin layer on the surface side of the laminate (above the metal vapor deposition layer) to prevent yellowing, a phenomenon called bleed-out occurs, in which the additive precipitates on the surface, which can result in a deterioration of the metallic luster or in insufficient adhesion between the layers. The present invention aims to provide a laminate with excellent weather resistance, i.e., a laminate that exhibits less deterioration in metallic luster, is less likely to yellow, and is less likely to experience changes in appearance even when exposed to ultraviolet light or high temperature and humidity for a long period of time, and a transfer film for obtaining the same. [Means for solving the problem]

[0007] The present invention comprises the following aspects. (Section 1) A transfer film in which at least a release layer, an intermediate layer, a deposition base layer, a metal deposition layer, and an adhesive layer are arranged in this order on a releasable substrate. The release layer, the intermediate layer, and the deposition base layer are all made of a reaction-cured product of at least a polyol and a polyisocyanate, A transfer film characterized by satisfying the following conditions A) to C): A) The polyisocyanate constituting the release layer is either an aliphatic or alicyclic isocyanate, or a combination thereof. B) The polyisocyanate constituting the intermediate layer is either an aliphatic, alicyclic, or araliphatic isocyanate, or a combination thereof. C) The polyisocyanate that constitutes the deposition underlayer is an aromatic isocyanate. (Section 2) Item 2. The transfer film according to item 1, wherein the polyisocyanate constituting the intermediate layer is an aromatic aliphatic isocyanate. (Section 3) Item 3. The transfer film according to item 1 or 2, wherein the polyols constituting the release layer, the intermediate layer, and the deposition primer layer are all acrylic polyols. (Section 4) Item 4. The transfer film according to item 3, wherein the metal of the metal deposition layer is indium, tin, chromium, or aluminum. (Section 5) A laminate in which at least an adhesive layer, a metal vapor deposition layer, a vapor deposition base layer, an intermediate layer, and a release layer are arranged in this order on a substrate to be decorated. The release layer, the intermediate layer, and the deposition base layer are all made of a reaction-cured product of at least a polyol and a polyisocyanate, A laminate characterized by satisfying the following conditions A) to C): A) The polyisocyanate constituting the release layer is either an aliphatic or alicyclic isocyanate, or a combination thereof. B) The polyisocyanate constituting the intermediate layer is either an aliphatic, alicyclic, or araliphatic isocyanate, or a combination thereof. C) The polyisocyanate that constitutes the deposition underlayer is an aromatic isocyanate. (Section 6) Item 6. The laminate according to Item 5, wherein the polyisocyanate constituting the intermediate layer is an aromatic aliphatic isocyanate. (Section 7) Item 7. The laminate according to Item 5 or 6, wherein the polyols constituting the release layer, intermediate layer, and deposition primer layer are all acrylic polyols. (Section 8) Item 8. The laminate according to item 7, wherein the metal of the metal vapor deposition layer is indium, tin, chromium, or aluminum. [Effects of the Invention]

[0008] As described above, the laminate of the present invention comprises, from the outermost layer (the direction in which external light is incident), a release layer, an intermediate layer, and a vapor deposition primer layer, each of which is a reaction-cured product having a predetermined composition, laminated in this order. Due to the synergistic effect of these layers, these layers are less likely to yellow even when irradiated with ultraviolet light, and even if pinholes are present in the metal vapor deposition layer or the metal vapor deposition layer has a sea-island structure, the UV light is prevented from reaching the adhesive layer and the substrate to be decorated. Therefore, the laminate of the present invention has excellent weather resistance. Therefore, the laminate of the present invention has an excellent metallic luster derived from the metal vapor deposition layer, and even when exposed to external light containing ultraviolet light or high temperature and humidity for a long period of time, the metallic luster deteriorates little and yellowing does not occur easily. Furthermore, by using the transfer film of the present invention, the laminate can be easily obtained. [Brief explanation of the drawings]

[0009] [Figure 1] This is a diagram showing an example of the layer structure of a transfer film in one embodiment of the present invention, in which a peeling layer 2, an intermediate layer 3, a vapor deposition base layer 4, a metal vapor deposition layer 5, and an adhesive layer 6 are formed in this order on a releasable substrate 1. [Figure 2] This is a diagram showing an example of the layer structure of the laminate of the present invention obtained using the transfer film of the present invention in Figure 1, in which an adhesive layer 6, a metal vapor deposition layer 5, a vapor deposition base layer 4, an intermediate layer 3, and a release layer 2 are formed in this order on the surface of the substrate 7 to be decorated. DETAILED DESCRIPTION OF THE INVENTION

[0010] First, the transfer film of the present invention will be described. The transfer film of the present invention that can solve the above-mentioned problems includes, for example, the following configurations, but may have configurations other than those below. A) Releaseable substrate / peeling layer / intermediate layer / evaporation base layer / metal vapor deposition layer / adhesive layer B) Releaseable substrate / peeling layer / intermediate layer / evaporation base layer / metal vapor deposition layer / evaporation protective layer / adhesive layer C) Releaseable substrate / peeling layer / intermediate layer / colored layer / vapor deposition base layer / metal vapor deposition layer / vapor deposition protective layer / adhesive layer D) Releaseable substrate / peel layer / intermediate layer / printing layer / evaporation base layer / metal vapor deposition layer / evaporation protective layer / adhesive layer In the following description, among the above-exemplified configurations, the layers located to the right of the release layer (all layers excluding the releasable substrate of the transfer film) will be collectively referred to as transfer layers. Each layer constituting the transfer film of the present invention will be explained below.

[0011] (Release base material) The release substrate used in the transfer film of the present invention can be any substrate that can form a releasable transfer layer of the transfer film of the present invention when the transfer film of the present invention is used for transfer processing, and can be a sheet of a material with release properties, or a substrate that has been surface-treated to impart release properties or that has a release layer made of a resin or the like with release properties. The surface treatment and release layer for imparting release properties can be formed using conventionally known methods. The material of the release substrate can be appropriately selected from paper, plastic film, etc. It is particularly preferable to use a plastic film because it is less likely to curl or crease during processing, such as forming a release layer.

[0012] (Plastic film) The plastic film used for the releasable substrate is not particularly limited as long as it is a plastic film generally used for transfer films, and various conventionally known plastic films such as polyethylene terephthalate film, polycarbonate film, polyethylene film, polypropylene film, and polyamide film can be used.

[0013] The plastic film may be unstretched, uniaxially stretched, or biaxially stretched, and may contain various additives such as antistatic agents, colorants, heat stabilizers, etc. The type and shape of the plastic film may be appropriately selected depending on the desired use and purpose.

[0014] Furthermore, in order to make the transfer film of the present invention more decorative, the surface of the releasable substrate (the side having releasability) may be subjected to various processes such as hairline processing, matte processing, embossing, etc.

[0015] The thickness of the release substrate used in the transfer film of the present invention is not particularly limited, but is preferably 12 μm or more and 250 μm or less. Furthermore, when transferring to a substrate to be decorated with particularly large surface irregularities, the thickness of the release substrate 1 is more preferably 25 μm or more and 50 μm or less. A thickness of the release substrate 1 thinner than 12 μm is undesirable because it may be prone to curling and creases when forming a release layer or the like on the release substrate or during the production of the transfer film of the present invention. A thickness of the release substrate thicker than 250 μm is undesirable because it may become too stiff and may have difficulty conforming to the surface irregularities of a substrate to be decorated with large surface irregularities when performing transfer processing using the transfer film of the present invention.

[0016] (peeling layer) The release layer in the present invention is a layer formed on a releasable substrate for the purpose of facilitating peeling of the transfer layer from the releasable substrate of the transfer film of the present invention when performing transfer processing using the transfer film of the present invention. Furthermore, the release layer is transferred from the releasable substrate to the surface of the substrate to be decorated as part of the transfer layer during transfer processing, and is formed on the outermost surface of the laminate.

[0017] The release layer of the present invention is a layer for suppressing yellowing of a laminate obtained using the transfer film of the present invention. The release layer is made of a resin, and is composed of a reaction cured product of at least a polyol and an aliphatic or alicyclic isocyanate. Conventional polyols such as acrylic polyols, polyester polyols, and urethane polyols can be used as the polyol. However, acrylic polyols are preferred because they stabilize release properties and have particularly excellent weather resistance. The hydroxyl value of the polyol is preferably in the range of 5 mgKOH / g to 60 mgKOH / g, and more preferably 10 mgKOH / g to 50 mgKOH / g, since the desired weather resistance can be easily obtained. By using an aliphatic or alicyclic isocyanate, or a combination thereof, as the polyisocyanate constituting the release layer, the release layer located on the outermost surface of the laminate obtained using the transfer film becomes a layer that is resistant to yellowing. Therefore, even when the laminate of the present invention is exposed to external light, including ultraviolet light, the occurrence of yellowing of the laminate can be suppressed. Specific examples of aliphatic and alicyclic isocyanates include aliphatic diisocyanates such as hexamethylene diisocyanate (HDI) and pentamethylene diisocyanate; and alicyclic polyisocyanates such as isophorone diisocyanate (IPDI), norbornane diisocyanate, hydrogenated diphenylmethane diisocyanate, hydrogenated tolylene diisocyanate, hydrogenated xylylene diisocyanate, 1,3-bis(isocyanatomethyl)-cyclohexane, and dicyclohexylmethane-4,4'-diisocyanate. Among these, HDI-based polyisocyanates and IPDI-based polyisocyanates are particularly suitable. Furthermore, the molar ratio (NCO / OH) of the isocyanate group (NCO) of the polyisocyanate to the hydroxyl group (OH) of the polyol is preferably in the range of NCO / OH=0.1 or more and 5 or less, and more preferably NCO / OH=0.2 or more and 2 or less, since this makes it easier to obtain the desired weather resistance. In addition, by adjusting the interlayer peel strength between the releasable substrate and the release layer, it is possible to suppress the occurrence of foil burrs (a phenomenon in which all or part of the transfer layer of the non-transferred portion near the transfer layer of the transferred portion during transfer processing peels off from the releasable substrate while remaining connected to the transferred portion). The interlayer peel strength can be adjusted, if necessary, by selecting a conventionally known method such as a method of changing the resin composition or a method of changing the thickness of the release layer. The release layer may contain other components in addition to the above components, provided that the object of the present invention is not impaired. Examples of other components that can be used as needed include antistatic agents, polymerization inhibitors, matting agents, antifoaming agents, dispersants, antisettling agents, leveling agents, water and oil repellents, heat stabilizers, light stabilizers, adhesion improvers, photosensitizers, antibacterial agents, antifungal agents, antiviral agents, silane coupling agents, antiscratch agents, and thermoplastic components.

[0018] The thickness of the release layer may be selected appropriately within a range that achieves the above-mentioned objective, and is preferably in the range of 0.1 μm to 10 μm, and more preferably 1 μm to 10 μm, as this makes it easier to obtain the desired weather resistance. The release layer can be formed by a conventional coating method such as gravure coating, reverse coating, die coating, reverse gravure coating, or bar coating, and the processing method may be a sheet-feed method (batch method) or a roll-to-roll method. These methods and methods may be appropriately selected depending on the purpose.

[0019] (middle class) The intermediate layer of the present invention is a layer for suppressing yellowing and UV transmission of a laminate obtained using the transfer film of the present invention. The intermediate layer is made of a resin, and is composed of at least a polyol and a reaction cured product of at least one of an aliphatic isocyanate, an alicyclic isocyanate, or an araliphatic isocyanate, or a combination thereof. Conventional polyols such as acrylic polyols, polyester polyols, and urethane polyols can be used as the polyol, but acrylic polyols are preferred from the viewpoint of weather resistance. The hydroxyl value of the polyol is preferably in the range of 5 mgKOH / g to 60 mgKOH / g, and more preferably in the range of 10 mgKOH / g to 50 mgKOH / g, since the desired weather resistance can be easily obtained. Although the aliphatic isocyanates and alicyclic isocyanates exemplified above may be used as the polyisocyanate, the use of aromatic aliphatic (aliphatic having an aromatic ring) isocyanates in particular can exhibit better weather resistance. Examples of aromatic aliphatic (aliphatic having an aromatic ring) isocyanates include xylylene diisocyanate (XDI)-based polyisocyanates. By using an aromatic aliphatic isocyanate as the polyisocyanate constituting the intermediate layer, the intermediate layer itself is less likely to yellow while absorbing the portion of the ultraviolet light that has passed through the release layer that is absorbed in the absorption range of the aromatic ring, and therefore, transmission of ultraviolet light to the vapor deposition base layer described below can be effectively suppressed while suppressing yellowing. Therefore, even when the laminate of the present invention is exposed to external light containing ultraviolet light, oxidation of the vapor deposition base layer by ultraviolet light can be suppressed. Furthermore, the molar ratio (NCO / OH) of the isocyanate group (NCO) of the polyisocyanate to the hydroxyl group (OH) of the polyol is preferably in the range of NCO / OH=0.1 or more and 5 or less, and more preferably NCO / OH=0.2 or more and 2 or less, since this makes it easier to obtain the desired weather resistance. Furthermore, the intermediate layer may contain one or more additives such as antistatic agents, ultraviolet absorbers, heat stabilizers, and curing agents, as needed. The amounts of the additives added may be appropriately selected depending on the purpose within a range that does not impair the effects of the present invention.

[0020] The thickness of the intermediate layer may be selected appropriately within a range that achieves the above-mentioned objective, and is preferably in the range of 0.5 μm or more and 5 μm or less, and more preferably 1 μm or more and 5 μm or less, as this makes it easier to obtain the desired weather resistance. The intermediate layer can be formed by a conventional coating method such as gravure coating, reverse coating, die coating, reverse gravure coating, or bar coating, and the processing method may be a sheet-feed method (batch method) or a roll-to-roll method. These methods and methods may be selected appropriately depending on the purpose.

[0021] (Vapor deposition base layer) The vapor-deposited underlayer in the present invention is a layer formed to ensure adhesion between the intermediate layer and the metal vapor-deposited layer formed thereon.

[0022] The deposition primer layer of the present invention is a layer for suppressing ultraviolet light transmission through a laminate obtained using the transfer film of the present invention. The deposition primer layer is made of a resin, and is a cured product of the reaction of at least a polyol and an aromatic isocyanate. As the polyol, conventionally known polyols such as acrylic polyols, polyester polyols, and urethane polyols can be used, but acrylic polyols are preferred from the viewpoint of chemical resistance and surface properties. The hydroxyl value of the polyol is preferably in the range of 5 mgKOH / g to 60 mgKOH / g, and more preferably in the range of 10 mgKOH / g to 50 mgKOH / g, as this facilitates obtaining the desired weather resistance. The glass transition temperature (Tg) of the polyol is preferably 50°C or higher, as the heat during vapor deposition processing may deteriorate the vapor deposition base layer. By using an aromatic isocyanate as the polyisocyanate constituting the vapor deposition primer layer, it absorbs a wide range of ultraviolet light. Therefore, even when the laminate of the present invention is exposed to external light, including ultraviolet light, it is possible to effectively suppress transmission of ultraviolet light to the adhesive layer and the substrate to be decorated. Specific examples of aromatic isocyanates include toluene diisocyanate (TDI) and diphenylmethane diisocyanate (MDI). In particular, TDI-based polyisocyanates and MDI-based polyisocyanates are preferred because they provide a coating film that can withstand the thermal load during vapor deposition processing to form the metal vapor deposition layer described below and are easy to use to obtain a transfer film with excellent metallic luster. Reaction-cured products using aromatic isocyanates tend to yellow due to ultraviolet light absorption, but the presence of the aforementioned release layer and intermediate layer suppresses yellowing to a level that does not pose a problem in practical use. Furthermore, the molar ratio (NCO / OH) of the isocyanate group (NCO) of the polyisocyanate to the hydroxyl group (OH) of the polyol is preferably in the range of NCO / OH=0.1 or more and 5 or less, and more preferably NCO / OH=0.2 or more and 2 or less, since this makes it easier to obtain the desired weather resistance. Furthermore, if necessary, the vapor deposition underlayer may contain one or more additives such as an antistatic agent, an ultraviolet absorber, a heat stabilizer, or a curing agent. The amount of each additive added may be appropriately selected depending on the purpose within a range that does not impair the effects of the present invention.

[0023] The thickness of the deposition base layer may be appropriately selected within a range that achieves the above-mentioned objective, and is preferably in the range of 0.1 μm or more and 5 μm or less. A thickness of 1 μm or more and 5 μm or less is more preferable, as this makes it easier to obtain the desired weather resistance and a film that can withstand the thermal load during deposition processing. The deposition underlayer can be formed by a conventional coating method such as gravure coating, reverse coating, die coating, reverse gravure coating, or bar coating, and the processing method may be a sheet-feed method (batch method) or a roll-to-roll method. These methods and methods may be selected appropriately depending on the purpose.

[0024] (Metal deposited layer) The metal vapor deposition layer in the present invention is a layer formed mainly for the purpose of imparting metallic luster to the laminate, and is a layer that is transferred and formed on the substrate to be decorated as part of the transfer layer when transfer processing is performed. Furthermore, by using a metal compound described below in the metal vapor deposition layer, properties such as barrier properties and electrical conductivity may be imparted in addition to the metallic luster.

[0025] The metal used in the metal vapor deposition layer may be any of various conventionally known metals such as aluminum, chromium, tin, gold, silver, copper, zinc, silicon, nickel, indium, lead, zinc, bismuth, titanium, iron, cobalt, and germanium, or alloys thereof, or metal compounds such as oxides, sulfides, and nitrides of the above conventionally known metals, and may be appropriately selected depending on the desired purpose. The metal vapor deposition layer may be a single layer or two or more layers, and when the metal vapor deposition layer 5 is a multi-layer structure of two or more layers, the metals used in each layer may be different or the same. The use of indium or tin as the metal is preferred because it makes it possible to easily obtain a discontinuous metal vapor deposition layer called a sea-island structure, which will be described later. The use of chromium as the metal is preferred because it can provide high chemical resistance and a luxurious metallic luster with a unique color, while the use of aluminum as the metal is preferred because it allows the transfer film of the present invention to be obtained inexpensively and also has excellent metallic luster.

[0026] Furthermore, by using a discontinuous metal vapor deposition layer called a sea-island structure, radio wave permeability can be achieved and cracks are less likely to occur in the metal vapor deposition layer when stretched during transfer processing, i.e., moldability is improved. Therefore, it can be used suitably for applications requiring radio wave permeability, high moldability, and weather resistance, such as automotive exterior applications such as emblems and front grilles. A discontinuous metal vapor deposition layer called a sea-island structure is typically a metal vapor deposition layer with metallic luster, in which the size of the metal islands is in the range of 1 nm to 2000 nm and the island spacing is in the range of 2 nm to 500 nm.

[0027] The thickness of the metal vapor deposition layer is preferably in the range of 5 nm to 600 nm. A thickness less than 5 nm is undesirable because it may not be possible to impart the desired metallic luster to the transfer film of the present invention. A thickness greater than 600 nm is undesirable because the heat during the vapor deposition process to form the metal vapor deposition layer or the heat during the transfer process may cause deformation or deterioration of the plastic film, or the desired sea-island structure may not be obtained when indium or tin is used, or cracks may occur in the metal vapor deposition layer during the transfer process, making it impossible to impart the desired metallic luster to the transfer film of the present invention. Furthermore, the metal vapor deposition layer can be formed using conventional methods such as vacuum deposition, ion plating, sputtering, and chemical vapor deposition. However, vacuum deposition is preferred from the viewpoint of film formation cost. The processing method may be a sheet-fed process (batch process) or a roll-to-roll process. These methods and methods may be selected appropriately depending on the purpose.

[0028] (adhesive layer) The adhesive layer in the present invention is a layer for adhering the transfer layer of the transfer film of the present invention to the substrate to be decorated. The adhesive layer formed on the transfer film of the present invention is not particularly limited as long as it is a thermoplastic resin generally used for adhesive layers of transfer films, and conventionally known resins such as acrylic resins, polyethylene resins, polypropylene resins, polystyrene resins, vinyl chloride resins, polyester resins, urethane resins, and vinyl acetate resins can be used, and any one of these, a mixed resin of two or more of these, or a copolymer resin of two or more of these may be used, and may be appropriately selected depending on the substrate to be decorated. Furthermore, when the substrate to be decorated is a resin molded product or a resin sheet, using a resin that is compatible with the resin used in the resin molded product or resin sheet will have good compatibility with the resin molded product or resin sheet, and is preferred in terms of adhesion.

[0029] The thickness of the adhesive layer may be appropriately selected within a range that allows the above-mentioned purpose to be achieved, and is preferably in the range of 0.1 μm to 10 μm. The adhesive layer can be formed by a conventional coating method such as gravure coating, reverse coating, die coating, reverse gravure coating, or bar coating, and the processing method can be a sheet-feed method (batch method) or a roll-to-roll method. These methods and methods can be selected appropriately depending on the purpose.

[0030] The transfer film of the present invention may have a layer structure in which one or more of a colored layer and a printed layer are formed to impart design to the laminate, as long as the effects of the present invention are not impaired.

[0031] (Colored layer, printing layer) The colored layer is a layer formed by adding a pigment or dye to a resin and covering the entire surface or a desired portion of the transfer film of the present invention. The printing layer is a layer formed by adding a pigment or dye to a resin to form a desired pattern on the transfer film of the present invention. The resin used for the colored layer and the printing layer is not particularly limited as long as it can achieve the above-mentioned purpose, and conventionally known resins such as polyethylene resins, polypropylene resins, polystyrene resins, vinyl chloride resins, polyester resins, acrylic resins, urethane resins, melamine resins, and epoxy resins can be used. Any one of these resins or a mixture of two or more of them may also be used, and may be appropriately selected depending on the purpose. Furthermore, the colored layer and the printed layer may contain one or more additives such as antistatic agents, ultraviolet absorbers, heat stabilizers, and curing agents, if necessary, and the amounts of the various additives added may be selected appropriately depending on the purpose.

[0032] The thickness of the colored layer and the printed layer may be any thickness that can achieve the desired purpose of the colored layer and the printed layer, preferably in the range of 0.1 μm to 5 μm, and may be selected appropriately depending on the purpose of formation. Furthermore, the colored layer 6 and the printed layer can be formed using conventional coating methods such as gravure coating, reverse coating, die coating, reverse gravure coating, and bar coating, and the processing method may be a sheet-fed method (batch method) or a roll-to-roll method. These methods and methods may be selected appropriately depending on the purpose.

[0033] When imparting design to the transfer film of the present invention by forming a colored layer, a printed layer, a metal vapor deposition layer, etc., the type of the colored layer, the printed layer, the metal vapor deposition layer, and the order in which they are formed may be appropriately selected depending on the purpose. Furthermore, the colored layer, the printed layer, and the metal vapor deposition layer may be formed over the entire surface or partially, and the position at which they are formed may be appropriately selected depending on the purpose. The colored layer may also serve as the intermediate layer, the vapor deposition underlayer, the anchor layer described below, the anticorrosive layer, the vapor deposition protective layer, or the like.

[0034] The transfer film of the present invention may further include, as necessary, layers other than those mentioned above, such as a vapor-deposited protective layer on one or both sides of the vapor-deposited metal layer to protect the vapor-deposited metal layer, an anticorrosive layer on one or both sides of the vapor-deposited metal layer to prevent corrosion of the vapor-deposited metal layer, an anchor layer to improve adhesion between the layers, etc. The material, forming method, thickness, forming position, etc. of the vapor-deposited protective layer may be any of those known in the art depending on the purpose.

[0035] The laminate of the present invention will be described below. The laminate of the present invention is obtained by successively forming the above-mentioned layers on a substrate to be decorated. The laminate of the present invention can be easily obtained by transferring the transfer layer formed on the transfer film of the present invention onto a substrate to be decorated. The following are examples of the configurations of the molded body of the present invention obtained using the above-mentioned transfer films A) and B). Note that molded body a) of the present invention corresponds to transfer film A) of the present invention, and laminate b) of the present invention corresponds to transfer film B). The laminate of the present invention may have a configuration other than the examples shown below. a) Peel layer / intermediate layer / evaporation base layer / metal vapor deposition layer / adhesive layer / decorated substrate b) Peeling layer / intermediate layer / evaporation base layer / metal vapor deposition layer / evaporation protective layer / adhesive layer / decorated substrate

[0036] (Base material to be decorated) The substrate to be decorated may be any material, regardless of shape or material, as long as it can be used as the laminate of the present invention, such as paper, fabric, resin sheet, or resin molded product. When the substrate to be decorated is a resin sheet or a resin molded product, the constituent resin can be any conventionally known resin, such as acrylic resin, polyethylene resin, polypropylene resin, polystyrene resin, vinyl chloride resin, polyester resin, urethane resin, vinyl acetate resin, ABS resin, or polycarbonate resin, depending on the desired purpose. Furthermore, it may be a mixed resin of one or more of these resins, or a copolymer resin of two or more of these resins. Furthermore, these resins may be transparent or colored.

[0037] When obtaining the laminate of the present invention using the transfer film of the present invention, the substrate to be decorated and the adhesive layer of the transfer film may be closely attached, and a thermal transfer method using a transfer machine such as a roll transfer machine or an up-down transfer machine may be used. However, the simultaneous molding and transfer method (in-mold molding method) described below, in which molding and transfer (decoration) to the substrate to be decorated are performed simultaneously, is more suitable.

[0038] [In-mold molding method (simultaneous molding transfer method)] The simultaneous molding and transfer method (in-mold molding method) involves first preparing an in-mold molding mold with a cavity of the desired shape and a transfer film, then placing the transfer film inside the mold with the adhesive layer of the transfer film facing the substrate to be decorated (a resin molded product). Then, suction is applied, and the injection molding mold is closed so that the transfer film is sandwiched between the mold and a thermoplastic resin is injected into the mold. The transfer layer of the transfer film is transferred to the surface of the substrate to be decorated by heat and pressure. After cooling, the laminate is removed from the mold, yielding a laminate in which a transfer layer has been formed on the substrate to be decorated.

[0039] As described above, the laminate of the present invention has a transfer layer with excellent weather resistance, so that the deterioration of metallic luster is small, yellowing is unlikely to occur, and changes in appearance are unlikely to occur. Therefore, it can be used for automotive exterior applications that require metallic luster and excellent weather resistance, but it can also be used for applications that do not require weather resistance. Furthermore, by using the transfer film of the present invention, the laminate of the present invention can be easily obtained. [Example]

[0040] The present invention will be explained in more detail below with reference to examples and comparative examples, but the present invention is not limited to these examples.

[0041] (Creating transfer film) [Transfer Film of Example 1] The following steps 1 to 6 were carried out to prepare the transfer film of the present invention. (Step 1) A mixed paint prepared by mixing two thermosetting resins (TM-REX JF-1 manufactured by Dainichiseika Color & Chemicals Mfg. Co., Ltd. and TM-REX HF-1 manufactured by Dainichiseika Color & Chemicals Mfg. Co., Ltd.) which were a mixture of acrylic resin and melamine resin in a weight ratio of JF-1:HF-1 = 50:50 was coated onto a 25 μm thick polyethylene terephthalate film using a gravure coating method, and the mixture was heated and cured to form a 1 μm thick release layer, thereby obtaining a releasable substrate. (Step 2) On the release layer of the above-mentioned release substrate, a mixed paint was applied by bar coating using a mixture of 100 parts by weight of acrylic polyol resin (Olestar Q164, manufactured by Mitsui Chemicals, Inc., with a hydroxyl value of 27 mgKOH / g) and 10 parts by weight of HDI polyisocyanate (Tosoh Corporation, Coronate 2715). The mixed paint was then heated and cured to form a 1 μm-thick release layer. The molar ratio (NCO / OH) of the isocyanate group (NCO) of the polyisocyanate to the hydroxyl group (OH) of the polyol was NCO / OH=1. (Step 3) On the release layer, a mixed coating was applied by bar coating using a mixture of 100 parts by weight of acrylic polyol resin (Olestar Q164, manufactured by Mitsui Chemicals, Inc.) and 13 parts by weight of XDI polyisocyanate (Takenate D-131N, manufactured by Mitsui Chemicals, Inc.), and the resulting mixture was heat-cured to form a 1 μm thick intermediate layer. The molar ratio (NCO:OH) of the isocyanate group (NCO) of the polyisocyanate to the hydroxyl group (OH) of the polyol was NCO / OH=1. (Step 4) A mixed coating of 100 parts by weight of acrylic polyol resin (Olestar Q164, manufactured by Mitsui Chemicals, Inc.) and 34 parts by weight of TDI polyisocyanate (Takenate D-204, manufactured by Mitsui Chemicals, Inc.) was applied onto the intermediate layer by bar coating and cured by heating to form a 1.5 μm thick deposition primer layer. The molar ratio (NCO / OH) of the isocyanate group (NCO) of the polyisocyanate to the hydroxyl group (OH) of the polyol was NCO / OH=1.5. (Step 5) Chromium was deposited on the above-mentioned deposition underlayer by vacuum deposition to form a metal deposition layer having a thickness of 150 nm. (Step 6) An acrylic-vinyl chloride-vinyl acetate copolymer resin was coated on the metal vapor deposition layer by a bar coating method to form an adhesive layer having a thickness of 1.5 μm.

[0042] [Transfer Films of Examples 2 to 9 and Comparative Examples 1 to 7] The transfer films of each example and comparative example were obtained in the same manner as in Example 1, except that the type of polyisocyanate contained in the release layer, intermediate layer, and vapor deposition base layer, the thickness of each layer, and the material of the metal vapor deposition layer were changed to those shown in Table 1.

[0043] (Preparation of Laminates - Examples 1 to 9 and Comparative Examples 1 to 7) A 2 mm thick ABS plate was used as the substrate to be decorated, and the transfer layer of the transfer film of each of the Examples and Comparative Examples obtained above was transferred onto the substrate to be decorated by a roll transfer method under conditions of 200°C and 50 mm / s, to obtain laminates of Examples 1 to 9 and Comparative Examples 1 to 7. Using these laminates, the weather resistance was evaluated under the following conditions.

[0044] (Weather resistance test) Using the laminates of each of the Examples and Comparative Examples obtained above, a weather resistance test was carried out under the following conditions. Equipment: Accelerated weather resistance tester, iSuper Xenon Tester XER-W83 (manufactured by Iwasaki Electric Co., Ltd.) Illuminance: 180w / m2 (wavelength: 300~400nm) Filter: Quartz glass / Borosilicate glass Test cycle: 48 minutes of irradiation only and 12 minutes of irradiation + water spray alternated Black Panel Temperature (BPT): 65±3℃ Humidity: 50±5% Integrated light amount: 300MJ / m2

[0045] (gloss retention rate) The specular gloss of each test piece (laminate) on the release layer side was measured using a BYK micro-TRI-gloss gloss meter at an incident angle of 85°, and the gloss retention before and after the weather resistance test was calculated using the following calculation method. If the gloss retention before and after the test is 80% or more, it can be evaluated that the metallic gloss has been maintained. Gloss retention rate (%) = (gloss after weather resistance test / gloss before weather resistance test) x 100 ◯: Gloss retention is 80% or more. ×: Gloss retention is less than 80%.

[0046] (yellowing) The color difference (ΔE) before and after the weather resistance test was measured for the release layer side of each test piece (laminate) using a color difference meter SD7000 manufactured by Nippon Denshoku Industries Co., Ltd., with a D65 light source and a viewing angle of 10° using the SCI method. If the color difference (ΔE) before and after the test is less than 3, it can be evaluated that no yellowing has occurred. ◯: The color difference (ΔE) before and after the weather resistance test is less than 3. ×: The color difference (ΔE) before and after the weather resistance test is 3 or more.

[0047] (Appearance change) Before and after the weather resistance test, each test piece (laminate) was observed from the surface on the release layer side, and changes in appearance such as foaming, peeling, and cracks were evaluated. ⊚: No or very slight changes in appearance such as foaming, peeling, or cracking were observed. ○: Slight changes in appearance such as foaming, peeling, or cracks are observed ×: Significant changes in appearance such as foaming, peeling, cracks, etc. are observed

[0048] (Evaluation method - Overall evaluation) Based on the results of the above tests, weather resistance was evaluated as follows: A rating of "2" or higher indicates that the product can be suitably used for exterior applications. 3: ΔE=less than 3, gloss retention rate of 80% or more, and no or very slight change in appearance. 2: ΔE=less than 3, gloss retention rate is 80% or more, and slight change in appearance is observed. 1: At least one of the following applies: ΔE=3 or more, gloss retention rate is less than 80%, or significant change in appearance is observed.

[0049] (Evaluation results) The laminates of Examples 1 to 9 and Comparative Examples 1 to 7 were evaluated by the above evaluation methods, and the results are shown in Table 1. The laminates of Examples 1 to 9 of the present invention were excellent in weather resistance, with little deterioration in metallic luster, little yellowing, and little change in appearance, even after the weather resistance test. [Table 1]

[0050] Furthermore, although excellent weather resistance can be obtained by increasing the thickness of the release layer, intermediate layer, and vapor deposition primer layer of the transfer film and laminate of the present invention, it is preferable that each layer be thin from the viewpoint of cost, etc. As in the above examples, the transfer film and laminate of the present invention were able to obtain the desired weather resistance even when each of the above layers was thin, about 1 μm thick.

[0051] As described above, the laminate of the present invention is a laminate with excellent weather resistance, showing little deterioration in metallic luster, little yellowing, and little change in appearance even after weather resistance testing. Therefore, it can be suitably used for automobile exterior parts such as front grilles and wheel caps, which require excellent weather resistance. Furthermore, the laminate of the present invention can be easily obtained by using the transfer film of the present invention. [Explanation of symbols]

[0052] 1 Releaseable base material 2. Peel layer 3. Middle class 4 Vapor deposition base layer 5 Metal vapor deposition layer 6 Adhesive layer 7 Base material to be decorated 10 Transfer film 11 Transfer layer 20 laminate

Claims

1. A transfer film in which at least a release layer, an intermediate layer, a deposition base layer, a metal deposition layer, and an adhesive layer are arranged in this order on a releasable substrate. The release layer, the intermediate layer, and the deposition base layer are all made of a reaction-cured product of at least a polyol and a polyisocyanate, A transfer film characterized by satisfying the following conditions A) to C): A) The polyisocyanate constituting the release layer is either an aliphatic or alicyclic isocyanate, or a combination thereof. B) The polyisocyanate constituting the intermediate layer is an aliphatic, alicyclic, or araliphatic isocyanate, or a combination thereof. C) The polyisocyanate constituting the deposition underlayer is an aromatic isocyanate.

2. 2. The transfer film according to claim 1, wherein the polyisocyanate constituting the intermediate layer is an araliphatic isocyanate.

3. 3. The transfer film according to claim 1, wherein the polyols constituting the release layer, the intermediate layer and the deposition primer layer are all acrylic polyols.

4. 4. The transfer film according to claim 3, wherein the metal of the metal vapor deposition layer is any one of indium, tin, chromium, and aluminum.

5. A laminate in which at least an adhesive layer, a metal vapor deposition layer, a vapor deposition base layer, an intermediate layer, and a release layer are arranged in this order on a substrate to be decorated. The release layer, the intermediate layer, and the deposition base layer are all made of a reaction-cured product of at least a polyol and a polyisocyanate, A laminate characterized by satisfying the following conditions A) to C): A) The polyisocyanate constituting the release layer is either an aliphatic or alicyclic isocyanate, or a combination thereof. B) The polyisocyanate constituting the intermediate layer is an aliphatic, alicyclic, or araliphatic isocyanate, or a combination thereof. C) The polyisocyanate constituting the deposition underlayer is an aromatic isocyanate.

6. 6. The laminate according to claim 5, wherein the polyisocyanate constituting the intermediate layer is an araliphatic isocyanate.

7. 7. The laminate according to claim 5, wherein the polyols constituting the release layer, the intermediate layer and the deposition primer layer are all acrylic polyols.

8. 8. The laminate according to claim 7, wherein the metal of the metal vapor deposition layer is any one of indium, tin, chromium, and aluminum.

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