Decorative film

Abstract

The present invention provides a decorative film which is excellent in terms of curved surface followability and weather resistance. The present invention specifically provides a decorative film which comprises a top coat layer that is formed of a starting material composition which contains a urethane resin and a carbodiimide compound, and a colored layer that contains an acrylic resin and a coloring agent. The carbodiimide compound has an isocyanate group and a carbodiimide group. The top coat layer has a ratio of the peak intensity of a peak derived from the isocyanate group to the peak intensity of a peak derived from the carbodiimide group of 0.14 or more as determined by the infrared absorption spectrum.

Description

Decorative film

[0001] The present invention relates to a decorative film and a polyurethane film.

[0002] In recent years, CO ２ From the viewpoints of reducing solvent usage due to reduced emissions and shortening construction time, decorative films are being used instead of paint as a means of decorating the exterior of automobiles. Polyvinyl chloride is widely used as the resin material for decorative films for the exterior of automobiles due to its high formability, durability, and economical efficiency. However, polyvinyl chloride is prone to deterioration over time, and measures to improve weather resistance are required.

[0003] Patent Document 1 describes a synthetic resin skin material having a skin layer containing a fluororesin-containing layer on the surface of a base layer containing a polyvinyl chloride resin and a colorant. Patent Document 2 describes a decorative film for vehicle exteriors in which the resin layer and protective layer contain polyurethane resin.

[0004] JP 2016-137612 A JP 2020-84106 A

[0005] However, in synthetic resin skin materials that include a polyvinyl chloride resin-containing layer and a fluororesin-containing layer, although the weather resistance of the polyvinyl chloride is significantly improved, the fluororesin-containing layer is hard, so the synthetic resin skin material as a whole is also hard. Therefore, when applied to the surface of a curved substrate such as an automobile, the synthetic resin skin material may peel off and float over time.

[0006] Furthermore, in decorative films for exterior use of vehicles that contain polyurethane resins, the polyurethane resins are hydrolyzable, so that in outdoor applications, particularly in locations along the coast where there is strong influence of seawater or sea breezes, the polyurethane resins may decompose and cracks may occur on the surface. Therefore, there is room for improvement in the weather resistance of decorative films for exterior use of vehicles that contain polyurethane resins.

[0007] Therefore, an object of one aspect of the present invention is to provide a decorative film that is excellent in curved surface conformability and weather resistance.

[0008] The present invention includes the following aspects.

[0009] [1] A decorative film comprising: a top coat layer formed from a raw material composition containing a urethane resin and a carbodiimide compound; and a colored layer containing an acrylic resin and a colorant, wherein the carbodiimide compound has an isocyanate group and a carbodiimide group, and the top coat layer has a peak intensity ratio of a peak derived from an isocyanate group to a peak intensity of a peak derived from a carbodiimide group measured in an infrared absorption spectrum of 0.14 or more, for example, 0.14 or more and 0.48 or less, preferably 0.14 or more and 0.40 or less, more preferably 0.15 or more and 0.35 or less, even more preferably 0.15 or more and 0.33 or less, and still more preferably 0.15 or more and 0.32 or less.

[0010] [2] The decorative film according to [1], wherein the ratio is 0.14 or more and 0.48 or less.

[0011] [3] The decorative film according to [1] or [2], wherein the upper yield load at 20°C is 15.0 N / 10 mm or more and 20.0 N / 10 mm or less.

[0012] [4] The decorative film has a stress relaxation rate at 20 ° C. of 53% or more and 58% or less, preferably 54% or more and 57% or less, and more preferably 55% or more and 56% or less. [1] The decorative film according to any one of [3] to [4].

[0013] [5] The decorative film according to any one of [1] to [4], wherein the colored layer has a thickness of 100 μm or more, for example, 100 μm or more and 150 μm or less, preferably 100 μm or more and 130 μm or less, and more preferably 100 μm or more and 110 μm or less.

[0014] [6] The decorative film according to any one of [1] to [5], wherein the urethane resin is a polycarbonate-based urethane resin.

[0015] [7] A polyurethane film formed from a raw material composition containing a urethane resin and a carbodiimide compound, wherein the carbodiimide compound has an isocyanate group and a carbodiimide group, and the polyurethane film has a ratio of the peak intensity of a peak derived from an isocyanate group to the peak intensity of a peak derived from a carbodiimide group measured in an infrared absorption spectrum of 0.14 or more, for example, 0.14 or more and 0.48 or less, preferably 0.14 or more and 0.40 or less, more preferably 0.15 or more and 0.35 or less, even more preferably 0.15 or more and 0.33 or less, and still more preferably 0.15 or more and 0.32 or less.

[0016] According to one aspect of the present invention, a decorative film having excellent curved surface conformability and weather resistance can be provided.

[0017] Hereinafter, embodiments of the present invention will be described in detail. Note that the scope of the present invention is not limited to the embodiments described herein, and various modifications can be made without departing from the spirit of the present invention. The upper and lower limits of the numerical ranges described in this specification can be arbitrarily selected and combined from the numerical values ​​exemplified individually or the numerical ranges exemplified as numerical ranges to form a suitable numerical range. Furthermore, in this specification, the content of each component in each layer means the total amount of the multiple substances present in the layer when multiple substances corresponding to each component are present in the layer, unless otherwise specified.

[0018] [Decorative Film] The decorative film may include a top coat layer formed from a raw material composition containing a urethane resin and a carbodiimide compound, and a colored layer containing an acrylic resin and a colorant, and the carbodiimide compound may have an isocyanate group and a carbodiimide group. In addition, the top coat layer included in the decorative film may have a peak intensity (I ＮＣＮ ) the peak intensity (I ＮＣＯ ) ratio (I ＮＣＯ / I ＮＣＮ) (hereinafter, this ratio may be referred to as "NCO / NCN ratio") may be 0.14 or more. In this specification, the peak intensity means the intensity of the peak top of the maximum absorption peak in the infrared absorption spectrum. The maximum absorption peak derived from the carbodiimide group in the infrared absorption spectrum may be, for example, at 2100 cm －１ 2125cm or more －１ The maximum absorption peak due to the isocyanate group is observed in the following wave number range, for example, at 2240 cm －１ More than 2270cm －１ It is observed in the following wavenumber range:

[0019] The NCO / NCN ratio in the top coat layer is an index corresponding to the molar ratio of free isocyanate groups (NCO groups) to free carbodiimide groups (NCN groups) contained in the top coat layer. By setting the NCO / NCN ratio of the top coat layer to a specific value or higher, for example, 0.14 or higher, the weather resistance, such as hydrolysis resistance, of the decorative film tends to be improved. Since the hydrolysis resistance of the decorative film is one of the important properties that constitute the weather resistance of the decorative film, improving the hydrolysis resistance can improve the weather resistance.

[0020] Hydrolysis of urethane resins is particularly likely to occur under alkaline conditions. Seawater is generally alkaline, so hydrolysis of urethane resins is likely to occur in outdoor applications, such as in locations along the coast where seawater and sea breezes have a strong influence. Therefore, there is a demand for decorative films that have excellent hydrolysis resistance even when exposed to basic conditions due to the influence of seawater and sea breezes. In one embodiment of the present invention, the decorative film has an NCO / NCN ratio in the top coat layer of a specific value or higher, for example, 0.14 or higher, and therefore has excellent hydrolysis resistance even when exposed to basic conditions due to the influence of seawater and sea breezes. This is thought to be because the top coat layer contains a specific content ratio of free isocyanate groups and free carbodiimide groups, which contribute to hydrolysis resistance as described below, thereby gradually suppressing hydrolysis of the urethane resin.

[0021] The NCO / NCN ratio in the top coat layer may be, for example, 0.14 or more, preferably 0.15 or more. When the NCO / NCN ratio is equal to or more than the above lower limit, the weather resistance, for example, hydrolysis resistance, of the decorative film tends to be improved. The upper limit of the NCO / NCN ratio in the top coat layer is not particularly limited, and may be, for example, 0.48 or less, 0.40 or less, 0.35 or less, 0.33 or less, or 0.32 or less.

[0022] In one embodiment, the NCO / NCN ratio in the top coat layer may be, for example, 0.14 or more and 0.48 or less, preferably 0.14 or more and 0.40 or less, more preferably 0.15 or more and 0.35 or less, even more preferably 0.15 or more and 0.33 or less, and even more preferably 0.15 or more and 0.32 or less.

[0023] The NCO / NCN ratio in the top coat layer can be adjusted by the content of the carbodiimide compound having an isocyanate group and a carbodiimide group in the raw material composition forming the top coat layer, the content of the isocyanate group in the carbodiimide compound, the content of the carbodiimide compound without an isocyanate group, etc. The NCO / NCN ratio in the top coat layer can be measured using an infrared spectrophotometer, with the vertical axis of the measurement data representing absorbance (A) and the horizontal axis of the measurement data representing wavenumber (cm －１ ) can be calculated from the infrared absorption spectrum obtained by measuring by the attenuated total reflection (ATR) method under the conditions. A specific calculation method includes determining the molar concentration of NCO and the molar concentration of NCN using absorbance A=εcl (Beer-Lambert's law, ε: molar absorption coefficient, c: molar concentration, l: length), and calculating from the ratio of the molar concentration of NCO to the molar concentration of NCN thus determined. However, in this specification, since the molar absorption coefficient ε and length l (sample thickness) of NCO and NCN are the same, the NCO / NCN ratio in the top coat layer is calculated from the ratio of the absorbance of NCO to NCN, i.e., the peak intensity (I ＮＣＮ ) the peak intensity (I ＮＣＯ ) ratio (I ＮＣＯ / I ＮＣＮThe NCO / NCN ratio in the top coat layer can be measured and calculated, for example, by the method described in the Examples.

[0024] <Top Coat Layer> The decorative film includes a top coat layer. The top coat layer may be formed from a raw material composition containing a urethane resin and a carbodiimide compound having an isocyanate group and a carbodiimide group (hereinafter also referred to as an "NCO-containing carbodiimide compound"). The top coat layer contains at least a urethane resin, and the top coat layer may contain a urethane resin and an NCO-containing carbodiimide compound. Furthermore, the NCO-containing carbodiimide compound contained in the top coat layer may exist as a partial structure derived from the NCO-containing carbodiimide compound reacted with the urethane resin. Forming the top coat layer from a raw material composition containing a urethane resin and an NCO-containing carbodiimide compound not only suppresses hydrolysis of the urethane resin in the top coat layer, but also suppresses further decomposition by reacting the free carbodiimide groups with the urethane resin decomposition products such as carbamic acid, even if hydrolysis of the urethane resin generates urethane resin decomposition products such as carbamic acid. As a result, the weather resistance of the decorative film can be improved.

[0025] The NCO-containing carbodiimide compound can prevent hydrolysis of the urethane resin contained in the top coat layer or suppress the progress of hydrolysis of the urethane resin.

[0026] The isocyanate group contained in the NCO-containing carbodiimide compound is believed to exert two main effects.

[0027] The first effect is that the reaction of the isocyanate group with the urethane resin incorporates the NCO-containing carbodiimide compound into the urethane resin, thereby suppressing bleed-out of the NCO-containing carbodiimide compound. When a large amount of the carbodiimide compound is incorporated into the urethane resin, bleed-out of the carbodiimide compound may occur over time. Therefore, it is difficult to incorporate a large amount of the carbodiimide compound into the urethane resin. However, in the case of an NCO-containing carbodiimide compound having an isocyanate group, a covalent bond is formed between the NCO-containing carbodiimide compound and the urethane resin, thereby suppressing bleed-out. Therefore, a relatively large amount of the NCO-containing carbodiimide compound can be incorporated into the urethane resin.

[0028] The second effect is that when the decorative film comes into contact with water, the free isocyanate groups react with the water, trapping the water before the urethane resin is hydrolyzed, thereby preventing the hydrolysis of the urethane resin. Note that it is believed that the top coat layer contains both functional groups derived from the isocyanate groups that reacted with the urethane resin, which are derived from the NCO-containing carbodiimide compound, and unreacted free isocyanate groups.

[0029] When some urethane bonds in a urethane resin are cleaved by hydrolysis, the carbodiimide groups of the NCO-containing carbodiimide compound can react with decomposed products of the urethane resin, such as carbamic acid, produced by the cleavage of the urethane bonds to form new urethane bonds. Therefore, it is believed that the carbodiimide groups of the NCO-containing carbodiimide compound have the effect of suppressing the progress of hydrolysis of the urethane resin.

[0030] When the top coat layer of the decorative film comes into contact with water, the free isocyanate groups of the NCO-containing carbodiimide compound trap the water, preventing hydrolysis of the urethane resin. Next, when the free isocyanate groups in the top coat layer are consumed and urethane bonds of the urethane resin are cleaved, the free carbodiimide groups of the NCO-containing carbodiimide compound react with urethane resin decomposition products such as carbamic acid to form new urethane bonds. As a result of this stepwise suppression of hydrolysis of the urethane resin by the isocyanate groups and carbodiimide groups of the carbodiimide compound, the decorative film is believed to have excellent hydrolysis resistance.

[0031] The isocyanate group content in the NCO-containing carbodiimide compound may be, for example, 0.1 wt% or more, preferably 4.0 wt% or more, more preferably 6.0 wt% or more, and even more preferably 8.0 wt% or more. When the isocyanate group content in the NCO-containing carbodiimide compound is equal to or greater than the above-mentioned lower limit, it is easy to adjust the NCO / NCN ratio to equal to or greater than the above-mentioned lower limit, and weather resistance tends to be further improved. The upper limit of the isocyanate group content in the NCO-containing carbodiimide compound is not particularly limited, and may be, for example, 15.0 wt% or less, 12.0 wt% or less, 10.0 wt% or less, or 9.0 wt% or less. In this specification, the isocyanate group content A in the NCO-containing carbodiimide compound can be calculated using the formula weight 42 of the isocyanate group and the molar amount n in 1 g of the NCO-containing carbodiimide compound according to the following formula: The molar amount n in 1 g of the NCO-containing carbodiimide compound can be determined by titration.

[0032] A = 42 x n x 100

[0033] In one embodiment, the content of isocyanate groups in the NCO-containing carbodiimide compound may be, for example, 0.1% by weight or more and 15.0% by weight or less, preferably 4.0% by weight or more and 12.0% by weight or less, more preferably 6.0% by weight or more and 10.0% by weight or less, and even more preferably 8.0% by weight or more and 9.0% by weight or less.

[0034] The NCO-containing carbodiimide compound contained in the raw material composition for forming the top coat layer may be one type alone or a combination of two or more types. For example, from the viewpoint of adjusting the NCO / NCN ratio of the top coat layer, an NCO-containing carbodiimide compound having a high isocyanate group content and an NCO-containing carbodiimide compound having a low isocyanate group content may be used in combination.

[0035] The NCO-containing carbodiimide compound is not particularly limited as long as it has an isocyanate group and a carbodiimide group, and may be, for example, a polycarbodiimide resin having an isocyanate group and a carbodiimide group.

[0036] Examples of commercially available NCO-containing carbodiimide compounds include "Carbodilite (registered trademark) V-05" and "Carbodilite (registered trademark) V-07" (both manufactured by Nisshinbo Chemical Inc.).

[0037] The content of the NCO-containing carbodiimide compound in the raw material composition that forms the top coat layer may be, for example, 7.8 mass% or more and 32.3 mass% or less, preferably 8.6 mass% or more and 27.4 mass% or less, more preferably 9.4 mass% or more and 24.8 mass% or less, and even more preferably 10.1 mass% or more and 24.8 mass% or less, relative to the entire raw material composition.

[0038] The content of the NCO-containing carbodiimide compound in the raw material composition forming the top coat layer may be, for example, 9 parts by mass or more and 50 parts by mass or less, preferably 10 parts by mass or more and 40 parts by mass or less, more preferably 11 parts by mass or more and 35 parts by mass or less, even more preferably 12 parts by mass or more and 33 parts by mass or less, and even more preferably 12 parts by mass or more and 32 parts by mass or less, relative to 100 parts by mass of the urethane resin. When the content is equal to or greater than the lower limit, hydrolysis of the urethane resin tends to be less likely to proceed, and the weather resistance of the decorative film tends to be further improved. When the content is equal to or less than the upper limit, bleeding of the carbodiimide compound from the top coat layer in outdoor environments tends to be suppressed.

[0039] The top coat layer has a peak intensity (I AmideII OCON-H ) the peak intensity (I ＮＣＮ ) ratio (I ＮＣＮ / I AmideII OCON-H ) (hereinafter, this ratio may also be referred to as the "NCN / AmideII OCON-H ratio") may be, for example, 0.30 or more, preferably 0.40 or more, more preferably 0.45 or more, and even more preferably 0.50 or more. The upper limit of the NCN / AmideII OCON-H ratio in the top coat layer is not particularly limited, and may be, for example, 1.60 or less, 1.50 or less, 1.40 or less, or 1.30 or less. The maximum absorption peak resulting from the peak intensity of the peak derived from the urethane group in the infrared absorption spectrum may be, for example, at 1530 cm －１ 1580cm or more －１ It is observed in the following wavenumber range:

[0040] In one embodiment, the NCN / Amide II OCON-H ratio in the top coat layer may be, for example, 0.30 or more and 1.60 or less, preferably 0.40 or more and 1.50 or less, more preferably 0.45 or more and 1.40 or less, even more preferably 0.50 or more and 1.30 or less, still more preferably 0.52 or more and 1.28 or less, or 0.55 or more and 1.25 or less.

[0041] The NCN / Amide II OCON-H ratio in the top coat layer can be adjusted by, for example, the total content of the NCO-containing carbodiimide compound and the carbodiimide compound having no isocyanate group relative to the urethane resin in the raw material composition that forms the top coat layer. The NCN / Amide II OCON-H ratio in the top coat layer can be measured, like the NCO / NCN ratio in the top coat layer, by measuring an infrared absorption spectrum by an attenuated total reflection (ATR) method using an infrared spectrophotometer, and can be measured, for example, by the method described in the Examples.

[0042] The raw material composition forming the top coat layer contains a urethane resin. Examples of urethane resins include polycarbonate-based urethane resins, polycaprolactone-based urethane resins, polyether-based urethane resins, polyester-based urethane resins, and polyolefin-based urethane resins. These polyurethane resins have a main chain of polycarbonate, polycaprolactone, polyether, polyester, polyolefin, or the like, and a urethane structure. Here, the urethane structure is preferably a urethane structure derived from an aliphatic isocyanate or an alicyclic isocyanate. From the viewpoint of imparting superior hydrolysis resistance to the decorative film, the urethane resin is preferably at least one selected from the group consisting of polycarbonate-based urethane resins and polycaprolactone-based urethane resins, and more preferably a polycarbonate-based urethane resin.

[0043] Examples of polycarbonates constituting urethane resins include 1,6-hexanediol carbonate, 3-methyl-1,5-pentanediol carbonate, 1,10-decanediol carbonate, and cyclohexanedimethanol carbonate. Examples of polycaprolactones constituting urethane resins include polycaprolactone diol and polycaprolactone triol. Examples of polyethers constituting urethane resins include polytetramethylene ether glycol (PTMEG) and polyoxypropylene glycol (PPG). Examples of polyesters constituting urethane resins include polyester polyols, such as polycondensates of aliphatic carboxylic acids such as malonic acid, succinic acid, or adipic acid, or aromatic carboxylic acids such as phthalic acid, with polyhydric alcohols such as ethylene glycol, diethylene glycol, or propylene glycol.

[0044] Examples of aliphatic isocyanates include hexamethylene diisocyanate (HDI), pentamethylene diisocyanate, tetramethylene diisocyanate, 2,2,4-trimethyl-1,6-diisocyanatohexane, and lysine diisocyanate. Examples of alicyclic isocyanates include 4,4'-dicyclohexylmethane diisocyanate (H １２ MDI), isophorone diisocyanate (IPDI), 1,3-bis(isocyanatomethyl)cyclohexane (1,3-H ６ XDI), norbornane diisocyanate (NBDI), etc.

[0045] The urethane resin is produced by polymerizing a main chain capable of constituting the urethane resin with an isocyanate compound by a known polymerization method.

[0046] Examples of commercially available urethane resins include Resamine (registered trademark) NE-8836, NE-8850, and NE-8811 (all manufactured by Dainichiseika Color & Chemicals Mfg. Co., Ltd.), Miractoran (registered trademark) E580, E585, E590, E595, E598, E980, E985, E990, E995, and E998 (all manufactured by Nippon Miractoran Co., Ltd.), NY88A10F, NY993-10HB4, and NY585N11A (manufactured by F.C.I. Co., Ltd.), and Crisvon (registered trademark) NY-393, NY-331, and NY-328FTR (manufactured by DIC Corporation).

[0047] The raw material composition forming the top coat layer may contain a resin other than the urethane resin. Examples of the other resin include a urea resin and an acrylic resin. The content of the other resin in the raw material composition forming the top coat layer may be, for example, 5 parts by mass or more and 30 parts by mass or less, preferably 10 parts by mass or more and 20 parts by mass or less, or 15 parts by mass or less, relative to 100 parts by mass of the urethane resin. In one embodiment, the raw material composition forming the top coat layer may not contain a resin other than the urethane resin.

[0048] The content of the urethane resin in the raw material composition that forms the top coat layer may be, for example, 60.0 mass% or more and 93.0 mass% or less, preferably 65.0 mass% or more and 92.0 mass% or less, more preferably 67.0 mass% or more and 91.0 mass% or less, and even more preferably 70.0 mass% or more and 90.0 mass% or less, relative to the entire raw material composition.

[0049] The raw material composition forming the top coat layer may further contain other components in addition to the urethane resin and the NCO-containing carbodiimide compound. Examples of the other components include ultraviolet absorbers, light stabilizers, plasticizers, extender pigments, matting agents, etc. Examples of the ultraviolet absorbers include benzotriazole-based compounds, benzophenone-based compounds, cyanoacrylate-based compounds, ultrafine zinc oxide, titanium oxide, etc. Examples of the light stabilizers include hindered amine-based compounds, etc.

[0050] When the raw material composition forming the top coat layer contains other components, the content of the other components may be, for example, 0.01 parts by mass or more and 10 parts by mass or less, preferably 0.1 parts by mass or more and 8 parts by mass or less, more preferably 0.5 parts by mass or more and 5 parts by mass or less, and even more preferably 1 part by mass or more and 3 parts by mass or less, relative to 100 parts by mass of the urethane resin.

[0051] The top coat layer may have an upper yield point load at 20°C of, for example, 3.5 N / 10 mm or more and 9.0 N / 10 mm or less, preferably 4.0 N / 10 mm or more and 7.5 N / 10 mm or less, more preferably 4.4 N / 10 mm or more and 6.5 N / 10 mm or less, even more preferably 4.6 N / 10 mm or more and 6.2 N / 10 mm or less, and even more preferably 4.8 N / 10 mm or more and 6.0 N / 10 mm or less. When the upper yield point load of the top coat layer is equal to or greater than the lower limit, the application of the decorative film tends to be improved and the occurrence of wrinkles during application of the decorative film tends to be suppressed. Furthermore, when the upper yield point load of the top coat layer is equal to or less than the upper limit, the curved surface conformability of the decorative film tends to be improved and the occurrence of lifting after application tends to be suppressed. The upper yield point load can be measured by a tensile test, for example, by the method described in the Examples. In this specification, the upper yield point load can be determined by measuring a 10 mm wide sample with a known measuring device such as a Tensilon universal testing machine. The upper yield point load is the load at the upper yield point of the sample observed in a tensile test, and since it is a load measured using a 10 mm wide sample, its unit is expressed as "N / 10 mm." In this specification, "curved surface conformability" refers to the property of a decorative film that is difficult to lift when attached to a curved portion such as an uneven portion.

[0052] The change in the elongation at break of the top coat layer before and after the weather resistance test may be, for example, 0% or more and 10% or less, preferably 9% or less, and more preferably 8% or less, in absolute value. The elongation at break of the top coat layer before the weather resistance test may be, for example, 150% or more. The elongation at break of the top coat layer can be measured using a known measuring device such as a Tensilon universal testing machine, for example, by the method described in the Examples. The weather resistance test may be, for example, Weather Resistance Test B described in the Examples.

[0053] The thickness of the top coat layer may be, for example, 15 μm or more and 60 μm or less, preferably 18 μm or more and 50 μm or less, more preferably 20 μm or more and 40 μm or less, and even more preferably 25 μm or more and 30 μm or less. From the viewpoint of protecting the colored layer with a sufficient thickness, the thickness of the top coat layer is preferably equal to or more than the above lower limit. The thickness of the top coat layer can be measured with a micrometer and calculated as the arithmetic average of the measured values ​​at five points.

[0054] The top coat layer can be produced, for example, by preparing a raw material composition in the form of a dispersion containing a urethane resin, an NCO-containing carbodiimide compound, other components, and an organic solvent, casting the raw material composition in the form of a dispersion to form a coating film, and then solidifying or curing the coating film.

[0055] <Colored Layer> The colored layer may contain an acrylic resin and a colorant. For example, the colored layer may be a layer in which a colorant is dispersed in an acrylic resin matrix resin. Note that "acrylic resin" is a general term for acrylic resin and methacrylic resin.

[0056] The acrylic resin contained in the colored layer may be one type of resin, or may be a combination of two or more types of resins with different hardnesses. Examples of hard resins with relatively high hardness in the combination include hard acrylic resins used in films, sheets, and the like formed by melt extrusion. Examples of soft acrylic resins with relatively low hardness in the combination include resins for adjusting fluidity and resins for soft materials. From the viewpoint of adjusting the mechanical properties of the decorative film and achieving the physical properties described below, the acrylic resin preferably includes a hard acrylic resin and a soft acrylic resin.

[0057] In this specification, the term "hard acrylic resin" refers to an acrylic resin that, when formed into a sheet material having a thickness of 100 μm and a width of 10 mm, has an upper yield point load of 10.0 N / 10 mm or more at 20° C. The upper yield point load can be measured using a known measuring device such as a Tensilon universal testing machine.

[0058] When the upper yield point load of a hard acrylic resin is a specified value or more, the application properties of the decorative film (reduction of wrinkles during application) may be further improved, and when the upper yield point load is less than the specified value, the curved surface conformability of the decorative film may be further improved.

[0059] The upper yield point load of the hard acrylic resin may be, for example, 10.0 N / 10 mm or more and 35.0 N / 10 mm or less. The lower limit of the upper yield point load of the hard acrylic resin may be preferably 15.0 N / 10 mm or more, more preferably 16.0 N / 10 mm or more, from the viewpoint of further improving the workability of the decorative film. The upper limit of the upper yield point load of the hard acrylic resin may be preferably 30.0 N / 10 mm or less, more preferably 28.0 N / 10 mm or less, from the viewpoint of further improving the curved surface conformability of the decorative film. The upper yield point load of the hard acrylic resin may be preferably 15.0 N / 10 mm or more and 30.0 N / 10 mm or less, more preferably 16.0 N / 10 mm or more and 28.0 N / 10 mm or less.

[0060] The hard acrylic resin can be prepared by radical polymerization of known monomers that can constitute an acrylic resin. Examples of hard acrylic resins include polymethyl methacrylate and methyl methacrylate-styrene copolymer.

[0061] The hard acrylic resin may be an acrylic resin having a Shore A hardness of greater than 90. The "Shore A hardness" is measured, for example, using a durometer GS-706N manufactured by Teclock Corporation, and is the maximum value when a Type A sensor is pressed perpendicularly against the surface of the measurement target with a load of 1 kgf.

[0062] As the hard acrylic resin, for example, it is preferable to first select an acrylic resin having a Shore A hardness of greater than 90 as a standard, and then select from the selected acrylic resins a resin that will result in an upper yield point load of 10.0 N / 10 mm or more for the molded article that is the sheet material. The hard acrylic resin may be a commercially available product, and examples thereof include Parapet (registered trademark) GR-F1000P (Kuraray Co., Ltd.), Kane Ace (registered trademark) MC-732 (Kaneka Corporation), Dianale LP-3202, 3207, 3130, and 3121 (all Mitsubishi Chemical Corporation), and Delpet (Asahi Kasei Corporation).

[0063] In this specification, the soft acrylic resin refers to an acrylic resin that, when made into a sheet material of the above-mentioned size, has an upper yield point load of less than 10.0 N / 10 mm at 20°C.

[0064] When the upper yield point load of a soft acrylic resin is a specified value or higher, the application properties of the decorative film (reduction of wrinkles during application) tend to be improved, and when the upper yield point load is less than the specified value, the curved surface conformability of the decorative film tends to be improved.

[0065] The upper yield point load of the soft acrylic resin may be, for example, 2.0 N / 10 mm or more and less than 10.0 N / 10 mm. The lower limit of the upper yield point load of the soft acrylic resin may be preferably 3.0 N / 10 mm or more, more preferably 3.5 N / 10 mm or more, from the viewpoint of further improving the workability of the decorative film. Furthermore, the upper limit of the upper yield point load of the soft acrylic resin may be preferably 7.0 N / 10 mm or less, more preferably 5.0 N / 10 mm or less, and even more preferably 4.5 N / 10 mm or less, from the viewpoint of further improving the curved surface conformability of the decorative film. The upper yield point load of the soft acrylic resin may be preferably 3.0 N / 10 mm or more and 7.0 N / 10 mm or less, more preferably 3.5 N / 10 mm or more and 5.0 N / 10 mm or less, and even more preferably 3.8 N / 10 mm or more and 4.5 N / 10 mm or less.

[0066] The soft acrylic resin can be prepared by radical polymerization of known monomers that can constitute acrylic resins. Examples of the soft acrylic resin include polymethyl methacrylate and methyl methacrylate-styrene copolymer.

[0067] The soft acrylic resin may be an acrylic resin having a Shore A hardness of 70 or more and 90 or less.

[0068] As the soft acrylic resin, for example, it is preferable to first select an acrylic resin having a Shore A hardness of 70 or more and 90 or less, and then select from the selected acrylic resins a resin that will result in an upper yield point load of less than 10.0 N / 10 mm for the molded body that is the specified sheet material. The soft acrylic resin may be a commercially available product, and an example thereof is Parapet (registered trademark) SA-F1000P (Kuraray Co., Ltd.).

[0069] When a mixture of a hard acrylic resin and a soft acrylic resin is used as the acrylic resin, the mass-based mixing ratio of the soft acrylic resin to the hard acrylic resin may be, for example, 0.4 or more and 1.4 or less, preferably 0.42 or more and 1.2 or less, more preferably 0.5 or more and 1.1 or less, and even more preferably 0.6 or more and 1.0 or less.

[0070] At least one of the hard acrylic resin and the soft acrylic resin may be formed from a resin composition containing core-shell particles in which core particles having rubber elasticity are coated with an acrylic resin. Core-shell particles in which core particles having rubber elasticity are coated with an acrylic resin may be formed by polymerizing a monomer mixture containing core particles, a (meth)acrylic acid ester, and, optionally, a polyfunctional monomer copolymerizable therewith and another monofunctional monomer. At least one of the hard acrylic resin and the soft acrylic resin may be a thermoplastic elastomer. Note that "(meth)acrylic acid" is a general term for acrylic acid and methacrylic acid, and refers to either or both of them.

[0071] Examples of (meth)acrylic acid esters include esters of (meth)acrylic acid and saturated aliphatic alcohols having from 1 to 22 carbon atoms; esters of (meth)acrylic acid and alicyclic alcohols having 5 or 6 carbon atoms; and esters of (meth)acrylic acid and phenols or aromatic alcohols.

[0072] More specifically, examples of (meth)acrylic acid esters include methyl (meth)acrylate, ethyl (meth)acrylate, n-propyl (meth)acrylate, isopropyl (meth)acrylate, n-butyl (meth)acrylate, isobutyl (meth)acrylate, s-butyl (meth)acrylate, t-butyl (meth)acrylate, pentyl (meth)acrylate, hexyl (meth)acrylate, octyl (meth)acrylate, 2-ethylhexyl (meth)acrylate, dodecyl (meth)acrylate, myristyl (meth)acrylate, palmityl (meth)acrylate, stearyl (meth)acrylate, behenyl (meth)acrylate, cyclohexyl (meth)acrylate, phenyl (meth)acrylate, and benzyl (meth)acrylate. Note that "(meth)acrylate" is a general term for acrylate and methacrylate, and refers to either or both of them.

[0073] Examples of polyfunctional monomers include esters of unsaturated monocarboxylic acids and unsaturated alcohols; diesters of unsaturated monocarboxylic acids and glycols; aromatic divinyl monomers; diesters of dicarboxylic acids and unsaturated alcohols; and conjugated diene monomers.

[0074] Examples of unsaturated monocarboxylic acids include (meth)acrylic acid and cinnamic acid. Examples of unsaturated alcohols include allyl alcohol and methallyl alcohol. Examples of glycols include ethylene glycol, propanediol, butanediol, and hexanediol. Examples of aromatic divinyl monomers include divinylbenzene. Examples of dicarboxylic acids include phthalic acid, terephthalic acid, isophthalic acid, and maleic acid.

[0075] Examples of the conjugated diene monomer include butadiene, isoprene, 2,3-dimethylbutadiene, 2-methyl-3-ethylbutadiene, 1,3-pentadiene, 3-methyl-1,3-pentadiene, 2-ethyl-1,3-pentadiene, 1,3-hexadiene, 2-methyl-1,3-hexadiene, 3,4-dimethyl-1,3-hexadiene, 1,3-heptadiene, 3-methyl-1,3-heptadiene, 1,3-octadiene, cyclopentadiene, chloroprene, and myrcene.

[0076] More specifically, examples of the polyfunctional monomer include allyl (meth)acrylate, methallyl (meth)acrylate, allyl cinnamate, methallyl cinnamate, diallyl maleate, diallyl phthalate, diallyl terephthalate, diallyl isophthalate, divinylbenzene, ethylene glycol di(meth)acrylate, butanediol di(meth)acrylate, and hexanediol di(meth)acrylate.

[0077] Examples of other monofunctional monomers include aromatic vinyl monomers and vinyl cyanide monomers.

[0078] Examples of aromatic vinyl monomers include styrene, α-methylstyrene, 1-vinylnaphthalene, 3-methylstyrene, 4-propylstyrene, 4-cyclohexylstyrene, 4-dodecylstyrene, 2-ethyl-4-benzylstyrene, 4-(phenylbutyl)styrene, and halogenated styrenes.

[0079] Examples of vinyl cyanide monomers include acrylonitrile and methacrylonitrile.

[0080] The colorant contained in the colored layer may be a known pigment or dye used in paints for printing on resin films. The colorant may be a single type or a combination of two or more types. The colorant is used in an amount according to the desired color to be expressed in the decorative film.

[0081] Examples of white colorants include titanium oxide and barium sulfate.

[0082] Examples of black colorants include iron black, carbon black, and aniline black.

[0083] Examples of yellow colorants include cadmium yellow and oil yellow 2G.

[0084] Examples of orange colorants include chrome vermilion and cadmium orange.

[0085] Examples of red colorants include cadmium red, permanent red 4R, and oil red.

[0086] Examples of purple colorants include cobalt violet and anthraquinone violet.

[0087] Examples of blue colorants include ultramarine, Prussian blue, and cobalt blue.

[0088] Examples of green colorants include phthalocyanine green and chrome green.

[0089] The content of the colorant in the colored layer can be appropriately changed depending on the type of colorant. For example, in the case of a black pigment, the content may be 10 parts by mass or more and 30 parts by mass or less, and preferably 15 parts by mass or more or 25 parts by mass or less, per 100 parts by mass of the acrylic resin.

[0090] The thickness of the colored layer may be, for example, 60 μm or more and 150 μm or less. From the viewpoint of fully expressing the desired chromaticity, the lower limit of the thickness of the colored layer may be preferably 80 μm or more, more preferably 100 μm or more. The upper limit of the thickness of the colored layer can be appropriately determined from the above viewpoint, and may be preferably 130 μm or less, more preferably 110 μm or less. The thickness of the colored layer can be measured with a micrometer and calculated as the arithmetic average of the measurements at five points.

[0091] The upper yield point load of the colored layer at 20 ° C. may be, for example, 7.5 N / 10 mm or more and 18.0 N / 10 mm or less. The lower limit of the upper yield point load of the colored layer at 20 ° C. may be, from the viewpoint of improving application properties, preferably 8.0 N / 10 mm or more, more preferably 9.0 N / 10 mm or more, and even more preferably 10.0 N / 10 mm or more. The upper limit of the upper yield point load of the colored layer at 20 ° C. may be, from the viewpoint of improving curved surface conformability, preferably 15.0 N / 10 mm or less, more preferably 14.0 N / 10 mm or less, and even more preferably 13.5 N / 10 mm or less. When the upper yield point load of the colored layer at 20 ° C. is the lower limit or more, the occurrence of wrinkles tends to be easily suppressed when the decorative film is applied. Furthermore, when the upper yield point load of the colored layer at 20 ° C. is the upper limit or less, the occurrence of lifting after application tends to be easily suppressed. The colored layer may have an upper yield point load at 20° C. of preferably 8.0 N / 10 mm or more and 15.0 N / 10 mm or less, more preferably 9.0 N / 10 mm or more and 14.0 N / 10 mm or less, and even more preferably 10.0 N / 10 mm or more and 13.5 N / 10 mm or less. The upper yield point load of the colored layer can be adjusted by using (meth)acrylic resins having different upper yield point loads in combination in an appropriate amount ratio.

[0092] The colored layer may further contain other components in addition to the acrylic resin and colorant. Examples of the other components include ultraviolet absorbers, light stabilizers, plasticizers, extender pigments, matting agents, etc. Examples of the ultraviolet absorbers include benzotriazole compounds, benzophenone compounds, cyanoacrylate compounds, ultrafine zinc oxide, titanium oxide, etc. Examples of the light stabilizers include hindered amine compounds.

[0093] When the colored layer contains other components, the content of the other components may be, for example, 0.01 parts by mass or more and 10 parts by mass or less, preferably 0.1 parts by mass or more and 8 parts by mass or less, more preferably 0.3 parts by mass or more and 5 parts by mass or less, and even more preferably 0.3 parts by mass or more and 3 parts by mass or less, relative to 100 parts by mass of the acrylic resin.

[0094] The colored layer can be produced by mixing the components contained in the colored layer, such as an acrylic resin, a colorant, and other components, and molding the resulting mixture into a film. The film formation of the colored layer may be carried out by, for example, extrusion molding, calendar molding, etc.

[0095] <Adhesive Layer> The decorative film may further include layers other than the top coat layer and the colored layer. Examples of the other layers include an adhesive layer.

[0096] The decorative film may include a first pressure-sensitive adhesive layer interposed between the color layer and the top coat layer to bond the two layers together, i.e., in one embodiment, the first pressure-sensitive adhesive layer may be disposed between the top coat layer and the color layer.

[0097] The decorative film may further include a second pressure-sensitive adhesive layer on the side of the colored layer opposite the top coat layer. The second pressure-sensitive adhesive layer may be a pressure-sensitive adhesive layer for attaching the decorative film to an object to be decorated.

[0098] In one embodiment, the decorative film may include a first adhesive layer and a second adhesive layer, and may be a laminate in which a top coat layer, a first adhesive layer, a colored layer, and a second adhesive layer are laminated in this order.

[0099] The thickness of each of the first pressure-sensitive adhesive layer and the second pressure-sensitive adhesive layer may be appropriately set, for example, from 3 μm to 70 μm, preferably 10 μm to 50 μm, more preferably 20 μm to 45 μm, and even more preferably 25 μm to 40 μm, depending on the type of pressure-sensitive adhesive and the object to be adhered. The thickness of the first pressure-sensitive adhesive layer and the second pressure-sensitive adhesive layer may be the same or different.

[0100] The first and second pressure-sensitive adhesive layers are, for example, composed of a first pressure-sensitive adhesive and a second pressure-sensitive adhesive, respectively. As the first and second pressure-sensitive adhesives, various known pressure-sensitive adhesives, such as rubber-based, acrylic-based, silicone-based, and polyvinyl ether-based pressure-sensitive adhesives, can be used. The first and second pressure-sensitive adhesives may be the same or different. The first and second pressure-sensitive adhesives may be, for example, acrylic pressure-sensitive adhesives.

[0101] The acrylic pressure-sensitive adhesive may be composed of a homopolymer of a (meth)acrylic acid ester or a copolymer with a copolymerizable comonomer.

[0102] Examples of the (meth)acrylic acid ester include alkyl (meth)acrylic acid esters; hydroxyalkyl (meth)acrylic acid esters; alkylaminoalkyl (meth)acrylic acid esters; and glycidyl (meth)acrylic acid esters.

[0103] Examples of "alkyl esters" of (meth)acrylic acid include methyl ester, ethyl ester, butyl ester, 2-ethylhexyl ester, octyl ester, and isononyl ester.

[0104] Examples of "hydroxyalkyl esters" of (meth)acrylic acid include hydroxyethyl esters, hydroxybutyl esters, and hydroxyhexyl esters.

[0105] Examples of alkylaminoalkyl (meth)acrylates include dimethylaminoethyl (meth)acrylate and t-butylaminoethyl (meth)acrylate.

[0106] Examples of copolymerizable comonomers include (meth)acrylic acid, itaconic acid, maleic anhydride, (meth)acrylic acid amide, (meth)acrylic acid N-hydroxymethylamide, vinyl acetate, styrene, and acrylonitrile.

[0107] The above-mentioned pressure-sensitive adhesive may further contain additives such as a crosslinking agent, a tackifier, a filler, an antioxidant, and a colorant, as required.

[0108] Examples of the crosslinking agent include an isocyanate compound, a polyisocyanate compound, a melamine resin, a urea resin, a polyamine, an epoxy compound, and a metal chelate compound.

[0109] The adhesive may be an ultraviolet-curable adhesive further containing a polymerization initiator. The ultraviolet-curable adhesive may further contain an ultraviolet-curable component as needed.

[0110] The polymerization initiator may be, for example, a substance that is cleaved by ultraviolet light of an appropriate wavelength to produce radicals that can trigger the polymerization reaction. Examples of polymerization initiators include benzoin alkyl ethers, aromatic ketones, aromatic ketals, and thioxanthones.

[0111] Examples of benzoin alkyl ethers include benzoin methyl ether, benzoin isopropyl ether, and benzoin isobutyl ether. Examples of aromatic ketones include benzil, benzophenone, and α-hydroxycyclohexyl phenyl ketone. Examples of aromatic ketals include benzil dimethyl ketal. Examples of thioxanthones include chlorothioxanthone, dodecylthioxanthone, dimethylthioxanthone, and diethylthioxanthone.

[0112] The ultraviolet-curable component is a component that adds a carbon-carbon double bond to the side chain of the acrylic polymer. When the polymer is an ultraviolet-curable polymer having a carbon-carbon double bond in the side chain, the pressure-sensitive adhesive does not need to contain the ultraviolet-curable component.

[0113] Examples of the ultraviolet curable component include an ester of (meth)acrylic acid and a polyhydric alcohol, and an isocyanurate compound.

[0114] Examples of esters of (meth)acrylic acid and polyhydric alcohols include trimethylolpropane tri(meth)acrylate, pentaerythritol tri(meth)acrylate, tetraethylene glycol di(meth)acrylate, 1,6-hexanediol (meth)acrylate, neopentyl glycol di(meth)acrylate, and dipentaerythritol hexa(meth)acrylate.

[0115] Examples of isocyanurate compounds include 2-hydroxyethylbis(2-acryloxyethyl)isocyanurate and tris(2-methacryloxyethyl)isocyanurate.

[0116] The upper yield point load of the decorative film at 20 ° C. may be, for example, 14.5 N / 10 mm or more and 25.0 N / 10 mm or less. The lower limit of the upper yield point load of the decorative film at 20 ° C. may be preferably 14.5 N / 10 mm or more, more preferably 14.7 N / 10 mm or more, and even more preferably 15.0 N / 10 mm or more, from the viewpoint of improving application workability. The upper limit of the upper yield point load of the decorative film at 20 ° C. may be preferably 25.0 N / 10 mm or less, more preferably 23.0 N / 10 mm or less, and even more preferably 20.0 N / 10 mm or less, from the viewpoint of improving curved surface conformability. When the upper yield point load of the decorative film at 20 ° C. is equal to or greater than the lower limit, the occurrence of wrinkles during application tends to be suppressed. Furthermore, when the upper yield point load of the decorative film at 20 ° C. is equal to or less than the upper limit, the curved surface conformability of the decorative film is easily improved, and the occurrence of lifting after application tends to be suppressed. The lower limit of the upper yield point load of the decorative film at 20° C. may be preferably 14.5 N / 10 mm or more and 25.0 N / 10 mm or less, more preferably 14.7 N / 10 mm or more and 23.0 N / 10 mm or less, and even more preferably 15.0 N / 10 mm or more and 20.0 N / 10 mm or less. The upper yield point load of the decorative film can be adjusted by the upper yield point load of each layer that constitutes the decorative film.

[0117] The decorative film may have a stress relaxation rate at 20°C of, for example, 53% or more and 58% or less. When the stress relaxation rate of the decorative film is within the above range, the curved surface conformability of the decorative film is improved and the occurrence of lifting after application tends to be suppressed. Furthermore, when the stress relaxation rate of the decorative film is equal to or greater than the above upper limit, the occurrence of wrinkles when the decorative film is applied tends to be further suppressed. From the viewpoint of improving application ease, the lower limit of the stress relaxation rate of the decorative film may be preferably 53% or more, more preferably 54% or more, and even more preferably 55% or more. From the viewpoint of improving curved surface conformability, the upper limit of the stress relaxation rate of the decorative film may be preferably 58% or less, more preferably 57% or less. The stress relaxation rate of the decorative film at 20°C may be preferably 53% or more and 58% or less, more preferably 54% or more and 57% or less, and even more preferably 55% or more and 56% or less.

[0118] In this specification, the stress relaxation rate of a decorative film at 20°C is the rate of change in tensile load before and after stretching when the decorative film is stretched 5% (to 105% of its length) at a stretching rate of 300 mm / min for 5 minutes. The temperature of the decorative film when measuring the stress relaxation rate is 20°C. The stress relaxation rate of the decorative film can be calculated from the following formula, where x is the tensile load immediately after 5% stretching and y is the tensile load 5 minutes after 5% stretching.

[0119] Stress relaxation rate z [%] = {(x - y) / x} × 100

[0120] The stress relaxation rate of the decorative film can be determined by measuring the tensile load using a known measuring device such as a Tensilon universal testing machine. The stress relaxation rate of the decorative film can also be adjusted by the material resins of the top coat layer and colored layer, etc., that make up the decorative film, or the thickness of the layers.

[0121] In this specification, when the decorative film includes other layers such as a pressure-sensitive adhesive layer, the upper yield point load and stress relaxation rate of the decorative film respectively refer to the upper yield point load and stress relaxation rate including the other layers such as a pressure-sensitive adhesive layer. When the decorative film includes a first pressure-sensitive adhesive layer and a second pressure-sensitive adhesive layer in addition to a top coat layer and a colored layer, the upper yield point load and stress relaxation rate of the decorative film may be the upper yield point load and stress relaxation rate including the four layers of the top coat layer, the first pressure-sensitive adhesive layer, the colored layer, and the second pressure-sensitive adhesive layer. Furthermore, since the presence or absence of a second adhesive layer has almost no effect on the measured values ​​of the upper yield point load and stress relaxation rate, when the decorative film includes a first adhesive layer and a second adhesive layer in addition to a top coat layer and a colored layer, the upper yield point load and stress relaxation rate of the decorative film may be the upper yield point load and stress relaxation rate of the laminate including the three layers of the top coat layer, the first adhesive layer, and the colored layer, excluding the second adhesive layer.

[0122] The decorative film has an integrated light intensity of 1350 MJ / m ２The color difference ΔE before and after irradiation with light may be, for example, 0 or more and 3.0 or less, and the upper limit of the color difference may be preferably 3.0 or less, more preferably 1.5 or less, even more preferably 1.3 or less, and still more preferably 1.2 or less, from the viewpoint of weather resistance.

[0123] The color difference ΔE of the decorative film is L ＊ a ＊ b ＊ In the color system, lightness is L ＊ , L ＊ a ＊ b ＊ The position between magenta and green in the color space is a ＊ (negative values ​​lean towards green, positive values ​​lean towards magenta), L ＊ a ＊ b ＊ The position between yellow and blue in the color space is b ＊ (negative values ​​are bluer and positive values ​​are yellower), the difference in brightness before and after irradiation ΔL ＊ , a before and after irradiation ＊ Difference Δa ＊ and b before and after irradiation ＊ The difference Δb ＊ It can be calculated using the following formula:

[0124] Color difference ΔE={(ΔL ＊ ) ２ + (Δa ＊ ) ２ + (Δb ＊ ) ２} １／２

[0125] The color difference of the decorative film can be measured using a known measuring device such as a colorimeter. The light irradiation and color difference measurement are performed on the top coat layer side of the decorative film. The color difference of the decorative film can be adjusted by using a resin material with sufficient weather resistance, in other words, by using a resin material with sufficient weather resistance for at least one of a urethane resin and an acrylic resin. Furthermore, the light irradiation of the decorative film may be accompanied by an accelerated test according to the environment in which the decorative film will be used.

[0126] The decorative film has an integrated light intensity of 1350 MJ / m ２From the viewpoint of weather resistance, the change in gloss value at 60° before and after irradiation with light may be preferably within ±5, more preferably within ±4, and even more preferably within ±3.

[0127] The gloss value of the decorative film can be measured using a known measuring device such as a gloss meter. The light irradiation and gloss value measurement are performed on the top coat layer side of the decorative film. The gloss value of the decorative film can be adjusted by using a resin material with sufficient weather resistance, in other words, by using a resin material with sufficient weather resistance for at least one of a urethane resin and an acrylic resin. Furthermore, the light irradiation of the decorative film may be accompanied by an accelerated test according to the environment in which the decorative film will be used.

[0128] The thickness of the decorative film is represented by the sum of the thicknesses of the top coat layer, the colored layer, and the thicknesses of other layers, such as the first pressure-sensitive adhesive layer and the second pressure-sensitive adhesive layer, which are optionally included. The thickness of the decorative film may be preferably 100 μm or more and 300 μm or less, more preferably 150 μm or more and 250 μm or less, and even more preferably 180 μm or more and 220 μm or less.

[0129] The decorative film may have a ratio of the thickness of the top coat layer to the thickness of the colored layer of, for example, 0.10 or more and 1.00 or less. The lower limit of this ratio may preferably be 0.15 or more, 0.20 or more, or 0.25 or more. The upper limit of this ratio may preferably be 0.80 or less, 0.60 or less, 0.50 or less, or 0.40 or less.

[0130] [Method for Producing Decorative Film] The decorative film can be produced by a method that allows the top coat layer and the colored layer to be stacked in this order.

[0131] For example, the decorative film can be produced by a method including the steps of preparing a top coat layer, preparing a colored layer, and attaching the top coat layer to the colored layer.

[0132] The top coat layer and the color layer may be prepared by the methods described above.

[0133] The step of attaching a top coat layer to a colored layer may be, for example, a step of directly bonding the colored layer and the top coat layer by heat fusion or the like. Alternatively, the step of attaching a top coat layer to a colored layer may be a step of supplying a layer of material for the other layer to one surface of a previously prepared colored layer or top coat layer, and bonding the other layer onto the one layer. Furthermore, the step of attaching a top coat layer to a colored layer may be a step of attaching the top coat layer to a first adhesive layer obtained by applying a first adhesive to one surface of the colored layer. Bonding the colored layer and the top coat layer via the first adhesive layer is advantageous from the viewpoint of increasing the degree of freedom in the material design of both layers.

[0134] Furthermore, the production of the decorative film may further include other steps in addition to the steps described above. Such other steps may be, for example, a step of applying a second adhesive to a release sheet and then laminating a colored layer to the resulting coating. Having the second adhesive layer in the decorative film is advantageous from the viewpoint of increasing the convenience of the decorative film, since the decorative film can be attached to an object to be decorated by peeling off the release sheet.

[0135] The decorative film of this embodiment is suitable for use in applications in which the film is attached to an object to be decorated to decorate the object. The decorative film of this embodiment has excellent weather resistance, curved surface conformability, and application workability, and is therefore suitable for use as a vehicle exterior film that is adhered to exterior parts of a vehicle.

[0136] [Polyurethane Film and Manufacturing Method Thereof] The present invention also encompasses a polyurethane film formed from a raw material composition containing a urethane resin and a carbodiimide compound. The carbodiimide compound contained in the raw material composition for forming the polyurethane film may have an isocyanate group and a carbodiimide group. The polyurethane film may have a ratio of the peak intensity of the peak derived from the isocyanate group to the peak intensity of the peak derived from the carbodiimide group measured in an infrared absorption spectrum of 0.14 or more.

[0137] The polyurethane film has excellent weather resistance and can be suitably used as a top coat layer of a decorative film. The explanations regarding the polyurethane film, such as the components contained in the polyurethane film, the properties of the polyurethane film, and the manufacturing method of the polyurethane film, are the same as those described in the "Top Coat Layer" of the decorative film above.

[0138] The present invention will be explained in more detail by the following examples, but the present invention is not limited to these examples.

[0139] [Materials] The materials used in the examples and comparative examples are listed below.

[0140] <Urethane Resins> Urethane resin 1: Rezamin (registered trademark) NE-8836 (manufactured by Dainichiseika Color & Chemicals Mfg. Co., Ltd., polycarbonate-based) Urethane resin 2: NY88A10F (manufactured by F.C.I. Co., Ltd., polyether-based, melting temperature 150°C) Urethane resin 3: NY993-10HB4 (manufactured by F.C.I. Co., Ltd., polycaprolactone-based, melting temperature 160°C) Urethane resin 4: NY585N11A (manufactured by F.C.I. Co., Ltd., polyester-based, melting temperature 130°C)

[0141] <Acrylic Resins> Acrylic Resin 1 (Hard Acrylic Resin): Parapet (registered trademark) GR-F1000P (manufactured by Kuraray Co., Ltd., upper yield point load at 20°C when thickness is 100 μm is 27.1 N / 10 mm, Shore A hardness 100) Acrylic Resin 2 (Soft Acrylic Resin): Parapet (registered trademark) SA-F1000P (manufactured by Kuraray Co., Ltd., upper yield point load at 20°C when thickness is 100 μm is 3.9 N / 10 mm, Shore A hardness 70) Acrylic Resin 3 (Hard Acrylic Resin): Kane Ace (registered trademark) MC-732 (manufactured by Kaneka Corporation, upper yield point load at 20°C when thickness is 100 μm is 16.0 N / 10 mm, Shore A hardness 100)

[0142] <Vinyl chloride resin> Vinyl chloride resin: Kanevinyl (registered trademark) S1001N (manufactured by Kaneka Corporation, average degree of polymerization 1050)

[0143] <Carbodiimide Compounds> Carbodiimide compound 1: Carbodilite (registered trademark) V-05 (manufactured by Nisshinbo Chemical Inc., isocyanate group content 8.2% by weight) Carbodiimide compound 2: Carbodilite (registered trademark) V-07 (manufactured by Nisshinbo Chemical Inc., isocyanate group content 0.5% by weight) Carbodiimide compound 3: Carbodilite (registered trademark) V-09 (manufactured by Nisshinbo Chemical Inc., isocyanate group content 0.0% by weight)

[0144] <Additives> Additive 1: Tinuvin 213 (manufactured by BASF Japan Ltd., ultraviolet absorber) Additive 2: Tinuvin 234 (manufactured by BASF Japan Ltd., ultraviolet absorber)

[0145] <Adhesives> Adhesive 1: Acrylic adhesive (adhesive obtained by crosslinking an acrylic resin having a Tg of -25.2°C, a BA / MA / AA (composition ratio, mass ratio) of 72.0:18.0:10.0, and a weight average molecular weight (Mw) of 400,000 to 500,000 with an epoxy crosslinking agent (TETRAD-X, manufactured by Mitsubishi Gas Chemical Company, Inc.)) Adhesive 2: Acrylic adhesive (adhesive obtained by crosslinking a mixture of an acrylic resin having a Tg of -18.0°C, 2EHA / MA / AA (composition ratio, mass ratio) = 46.0:49.5:4.5, and a weight average molecular weight (Mw) of 400,000 to 600,000, and an acrylic resin having a Tg of 100.6°C, tBMA / 2HEMA (composition ratio, mass ratio) = 90.0:10.0, and a weight average molecular weight (Mw) of 5,000, and an epoxy crosslinking agent (TETRAD-X, manufactured by Mitsubishi Gas Chemical Company, Inc.)) In Adhesive 1 and Adhesive 2, BA represents n-butyl acrylate, MA represents methyl acrylate, AA represents acrylic acid, tBMA represents t-butyl methacrylate, 2EHA represents 2-ethylhexyl acrylate, and 2HEMA represents 2-hydroxyethyl methacrylate.

[0146] [Measurement Method] <Measurement of Infrared Absorption Spectrum of Top Coat Layer> The infrared absorption (IR) spectrum used to calculate the NCO / NCN ratio and the NCN / Amide II OCON-H ratio in the top coat layer was measured using a Spectrum 100(B) (infrared spectrophotometer manufactured by Perkin Elmer) in the measurement range of 4000-650 cm －１, Number of scans: 4, Spectrometer resolution: 4.00 cm －１ The measurement crystal is diamond / ZnSe, the number of reflections is 1, the vertical axis of the measurement data is absorbance (A), and the horizontal axis of the measurement data is wave number (cm －１ ) by attenuated total reflectance (ATR) measurement.

[0147] (NCO / NCN Ratio) For the top coat layer, an IR spectrum was obtained by the ATR method using a Spectrum 100(B) (an infrared spectrophotometer manufactured by Perkin Elmer) under the above measurement conditions. From the obtained IR spectrum, a peak (2100 to 2125 cm) derived from a carbodiimide group was observed. －１ Peak intensity (I ＮＣＮ ), and a peak due to an isocyanate group (2240 ​​to 2270 cm －１ Peak intensity (I ＮＣＯ ) and I ＮＣＮ I against ＮＣＯ The ratio (I ＮＣＯ / I ＮＣＮ ) was calculated.

[0148] (NCN / Amide II OCON-H Ratio) For the top coat layer, an IR spectrum was obtained by the ATR method using a Spectrum 100(B) (an infrared spectrophotometer manufactured by Perkin Elmer) under the above measurement conditions. From the obtained IR spectrum, a peak (2100 to 2125 cm) derived from the carbodiimide group was observed. －１ Peak intensity (I ＮＣＮ ), and a peak derived from a urethane group (1530 to 1580 cm －１ Peak intensity (I AmideII OCON-H ) and I AmideII OCON-H I against ＮＣＮ The ratio (I ＮＣＮ / I AmideII OCON-H ) was calculated.

[0149] <Upper Yield Point Load> A rectangular sample measuring 10 mm wide and 150 mm long was prepared and subjected to a tensile test using a TENSILON (registered trademark, manufacturer: A&D, model RTG-1310). Specifically, the distance between the chucks of the TENSILON was set to 100 mm, and the sample was clamped and fixed between the chucks. The sample was stretched at a constant tensile speed of 300 mm / min at 20°C, and the tensile load during stretching was measured. When the elastic limit of the hook is exceeded, the sample increases nonlinearly, reaching the upper yield point, and simultaneously necking occurs. The load at the upper yield point was taken as the upper yield point load. Note that a laminate not including a second pressure-sensitive adhesive layer was used as the sample to measure the upper yield point load of the decorative film.

[0150] <Stress Relaxation Rate> A rectangular sample measuring 10 mm wide and 100 mm long was prepared, and a tensile test was performed using a TENSILON (registered trademark, manufacturer: A&D, model RTG-1310). More specifically, the distance between the chucks of the TENSILON was set to 100 mm, and the sample was clamped and fixed between the chucks. The sample was stretched 5% at a tensile speed of 300 mm / min at 20°C, and the tensile load x immediately after 5% stretching and the tensile load y 5 minutes after 5% stretching were measured. The stress relaxation rate z was then calculated using the following formula. Note that, to measure the stress relaxation rate of the decorative film, a laminate not including a second pressure-sensitive adhesive layer was used as the sample. z [%] = {(x-y) / x} × 100

[0151] <Elongation at Break> The elongation at break of the top coat layer before and after weather resistance test B was measured as follows. A rectangular sample measuring 10 mm wide and 100 mm long was prepared, and a tensile test was performed using TENSILON (registered trademark, manufacturer: A&D, model RTG-1310). More specifically, the distance between the chucks of the TENSILON was set to 100 mm, and the sample was clamped and fixed between the chucks. The sample was stretched at a tension rate of 300 mm / min at 20°C, and the elongation % at the time the film broke was measured.

[0152] <Thickness> The thickness of each layer was measured with a micrometer and calculated as the arithmetic mean of the measurements at five points. The thickness of the top coat layer and the colored layer was measured individually, and the thickness of the pressure-sensitive adhesive layer was calculated by subtracting the thickness of the two films from the total thickness when sandwiched between two films with specified thicknesses.

[0153] [Evaluation Method] <Weather Resistance> The weather resistance of the decorative film was evaluated by the following Weather Resistance Test A and Weather Resistance Test B. Weather Resistance Test A is an accelerated test that simulates use in a general environment for decorative films. Weather Resistance Test B is an accelerated test that simulates use in an environment where the film is exposed to the effects of seawater or sea breezes, which are more likely to cause hydrolysis of the urethane resin.

[0154] [Weather Resistance Test A] A weather resistance test of the decorative film was carried out using a Daipla Metal Weather (Model KW-R7TP-A) manufactured by Daipla Wintes Co., Ltd. The sample stage on which the decorative film was placed was set at an inclination angle of 15°, the black panel temperature (BPT) was 63°C, and the light irradiation intensity was 750 W / m ２ The surface of the decorative film was wetted with water by showering for 2 minutes every 120 minutes, and this cycle was repeated for 500 hours. The cumulative light intensity was 1350 MJ / m ２ and the conditions of Test A correspond to a 4.5 year service life on an automotive surface.

[0155] The weather resistance of the decorative film was evaluated in Weather Resistance Test A from the viewpoints of color difference, gloss change, and abnormal appearance. The light irradiation, measurement of color difference and gloss change, and observation of appearance change were carried out on the top coat layer side of the decorative film.

[0156] (Color difference ΔE) Using a KONICA MINOLTA SPECTRO PHOTO METER CM-3600A, the L, a, and b values ​​of the decorative film before the weather resistance test A and the L, a, and b values ​​of the decorative film after the weather resistance test A were measured. ＊ , a ＊ , and b ＊ The values ​​were measured, and the color difference ΔE was calculated from the following formula and evaluated according to the following criteria: ΔE={(L ＊ -L) ２ + (a ＊ -a) ２ +(b ＊-b) ２} １／２

[0157] S: ΔE≦1.0 A: 1.0<ΔE≦1.5 B: 1.5<ΔE≦3.0 C: ΔE>3.0

[0158] (Change in Gloss) Using a digital variable angle glossmeter (model UGV-5) manufactured by Suga Test Instruments Co., Ltd., the change in gloss value at 60° of the decorative film before and after the weather resistance test A was measured and evaluated according to the following criteria.

[0159] A: The change in gloss value before and after the weather resistance test was within ±5. C: The change in gloss value before and after the weather resistance test was greater than ±5.

[0160] The decorative film was visually inspected before and after the weather resistance test A. The presence or absence of changes in appearance such as scratches or discoloration was observed and evaluated according to the following criteria.

[0161] (Appearance abnormalities) A: No appearance abnormalities were observed. B: Minor appearance abnormalities such as small scratches were observed. C: Obvious appearance abnormalities such as conspicuous scratches or yellowing were observed.

[0162] [Weather Resistance Test B] A strip of top coat layer film measuring 80 mm in width and 100 mm in length was prepared and immersed in a 0.4 N aqueous sodium hydroxide (NaOH) solution at 60°C for 3 days. After immersion, the top coat layer film was subjected to a weather resistance test of the top coat layer of the decorative film using a Daipla Metal Weather (Model KW-R7TP-A) manufactured by Daipla Wintes Co., Ltd. The sample stage on which the top coat layer was placed was set at an inclination angle of 15°, the black panel temperature (BPT) was set at 80°C, and the light irradiation intensity was set at 900 W / m ２ The surface of the topcoat layer film was wetted with water by showering for 2 minutes every 120 minutes, and this cycle was repeated for 50 hours. The cumulative light dose was 162 MJ / m ２ The conditions of Test B correspond to a 1.0 year outdoor exposure period on the surface of an automobile in a coastal area.

[0163] The weather resistance of the top coat layer of the decorative film was evaluated in Weather Resistance Test B from the viewpoint of changes in the elongation at break of the top coat layer and abnormal appearance.

[0164] (Change in elongation at break) The elongation at break of the top coat layer was measured before and after weather resistance test B and evaluated according to the following criteria: A: The rate of change in the elongation at break of the top coat layer before and after weather resistance test B was within 10%. C: The rate of change in the elongation at break of the top coat layer before and after weather resistance test B was greater than 10%.

[0165] (Appearance Abnormalities) A ​​strip-shaped sample having a width of 10 mm and a length of 100 mm was prepared from the top coat layer film after Weather Resistance Test B, and stretched to 100% using a TENSILON (registered trademark, manufacturer: A&D, model RTG-1310). Specifically, the distance between the chucks of the TENSILON was set to 100 mm, and the sample was clamped and fixed between the chucks. The sample was stretched to 100% at a constant tensile speed of 300 mm / min at 20°C. After stretching to 100%, the surface of the sample was visually observed to confirm the presence or absence of cracks (microcracks). Appearance abnormalities after Weather Resistance Test B were evaluated according to the following criteria.

[0166] A: No abnormalities in appearance were observed. B: Minor abnormalities in appearance such as small scratches were observed. C: Clear abnormalities in appearance such as noticeable scratches or yellowing were observed.

[0167] <Lifting (curved surface conformability)> A decorative film was attached to a urethane-coated panel having a partial structure corresponding to the uneven lines on the outer surface of an automobile. The decorative film attached to the above portion was left in an environment at 10°C. Separately, another decorative film similarly attached to the above portion was left in an environment at 23°C. The occurrence of lifting during the storage period was visually observed and evaluated according to the following criteria.

[0168] S: No lifting occurred even after 2 weeks in both the lifting evaluations at 10°C and 23°C. A: Lifting occurred more than 3 days but within 2 weeks in the lifting evaluation at 10°C. B: Lifting occurred more than 24 hours but within 3 days at 10°C. C: Lifting occurred within 24 hours in both the lifting evaluations at 10°C and 23°C.

[0169] <Wrinkles during application (application workability)> A decorative film was applied to a urethane-coated panel having a partial structure including uneven lines on the outer surface of an automobile. The occurrence of wrinkles in the decorative film during application was visually observed and evaluated according to the following criteria.

[0170] No (A): No wrinkles were generated when applied to the uneven lines of a car. Yes (C): Wrinkles were generated when applied.

[0171] <Overall Evaluation> The above evaluation results were converted into points based on the following criteria: S: 2 points A: 1 point B: 0 points C: -1 point

[0172] The scores for each decorative film were then totaled and evaluated according to the scores for each decorative film according to the following criteria: A: 10 points or more in total B: 5 points to 9 points in total C: 4 points or less in total

[0173] [Example 1] (Preparation of Top Coat Layer) A dispersion liquid containing 100 parts by mass of urethane resin 1 in a solution of isopropyl alcohol (IPA) / toluene = 1 / 1 (mass ratio) so as to have a solid content of 25 mass % was mixed with 12 parts by mass of carbodiimide compound 1 and 1.2 parts by mass of additive 1, and then cast. Next, the mixture was dried at 80 ° C. for 3 minutes and then at 140 ° C. for 3 minutes to prepare a top coat layer with a thickness of 30 μm.

[0174] (Preparation of Colored Layer) 50 parts by mass of acrylic resin 1, 50 parts by mass of acrylic resin 2, 0.3 parts by mass of additive 2, and 19 parts by mass of carbon black pigment (W-8012-G5, manufactured by Nichiko Bix Co., Ltd.) were dry blended, and then kneaded using a Henschel mixer. The mixture was then formed into a film having a thickness of 100 μm using a calendar molding machine set at 180° C. to prepare a colored layer.

[0175] (Adhesion between top coat layer and colored layer) A top coat layer was placed on a coating of PSA 1 formed by applying PSA 1 to one surface of the colored layer, and the top coat layer was adhered to the colored layer. In this way, a base film was produced in which the top coat layer, a first PSA layer consisting of PSA 1, and a colored layer were laminated in this order. The thickness of the first PSA layer was 30 μm.

[0176] (Adhesion of adhesive layer to colored layer) The colored layer of the base film was superimposed on a coating of adhesive 2 formed by applying adhesive 2 onto a release film, and then laminated. In this way, a decorative film was produced in which the top coat layer, first adhesive layer made of adhesive 1, colored layer, second adhesive layer made of adhesive 2, and release film were laminated in this order. The thickness of the second adhesive layer was 40 μm.

[0177] Examples 2 and 3 Decorative films were prepared in the same manner as in Example 1, except that the amounts of acrylic resin 1 and acrylic resin 2 were changed to those shown in Table 1 in preparing the colored layer.

[0178] Examples 4 and 8 Decorative films were prepared in the same manner as in Example 1, except that the amount of carbodiimide compound 1 was changed to the amount shown in Table 1 in preparing the top coat layer.

[0179] Example 5 A decorative film was produced in the same manner as in Example 1, except that 30 parts by mass of acrylic resin 2 and 70 parts by mass of acrylic resin 3 were used as the acrylic resins in producing the colored layer.

[0180] [Example 6] A decorative film was produced in the same manner as in Example 1, except that 20 parts by mass of carbodiimide compound 1 and 6 parts by mass of carbodiimide compound 2 were used as the carbodiimide compounds in producing the top coat layer.

[0181] [Example 7] A decorative film was produced in the same manner as in Example 1, except that 20 parts by mass of carbodiimide compound 1 and 6 parts by mass of carbodiimide compound 3 were used as the carbodiimide compounds in producing the top coat layer.

[0182] Comparative Example 1 A decorative film was produced in the same manner as in Example 1, except that no carbodiimide compound was used in the production of the top coat layer.

[0183] Comparative Examples 2 and 3 Decorative films were prepared in the same manner as in Example 1, except that the amount of carbodiimide compound 1 was changed to the amount shown in Table 2 in preparing the top coat layer.

[0184] Comparative Examples 4 and 5 Decorative films were prepared in the same manner as in Example 1, except that carbodiimide compound 2 or carbodiimide compound 3 was used instead of carbodiimide compound 1 in preparing the top coat layer.

[0185] Comparative Examples 6 to 10 Decorative films were prepared in the same manner as in Example 1, except that in preparing the colored layer, vinyl chloride resin or urethane resins 1 to 4 were used instead of the acrylic resin.

[0186] Reference Example 1 A decorative film was produced in the same manner as in Example 1, except that the colored layer and the first pressure-sensitive adhesive layer were not provided.

[0187] Tables 1 and 2 show the measurement and evaluation results of the decorative films, top coat layers, and colored layers of the Examples, Comparative Examples, and Reference Examples.

[0188]

[0189]

Claims

1. A decorative film comprising: a top coat layer formed from a raw material composition containing a urethane resin and a carbodiimide compound; and a colored layer containing an acrylic resin and a colorant, wherein the carbodiimide compound has an isocyanate group and a carbodiimide group, and the top coat layer has an infrared absorption spectrum in which the ratio of the peak intensity of the peak derived from the isocyanate group to the peak intensity of the peak derived from the carbodiimide group is 0.14 or more.

2. The decorative film according to claim 1, wherein the ratio is 0.14 or more and 0.48 or less.

3. The decorative film according to claim 1 or 2, wherein the upper yield point load at 20°C is 15.0 N / 10 mm or more and 20.0 N / 10 mm or less.

4. A decorative film according to any one of claims 1 to 3, wherein the decorative film has a stress relaxation rate of 53% or more and 58% or less at 20°C.

5. A decorative film according to any one of claims 1 to 4, wherein the colored layer has a thickness of 100 μm or more.

6. A decorative film according to any one of claims 1 to 5, wherein the urethane resin is a polycarbonate-based urethane resin.

7. A polyurethane film formed from a raw material composition containing a urethane resin and a carbodiimide compound, wherein the carbodiimide compound has an isocyanate group and a carbodiimide group, and the ratio of the peak intensity of the peak derived from the isocyanate group to the peak intensity of the peak derived from the carbodiimide group measured in an infrared absorption spectrum of the polyurethane film is 0.14 or more.

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