exterior film

Abstract

[Problem] To provide an exterior film capable of favorably absorbing sound of rain. [Solution] The exterior film comprises: a sound absorbing layer 50 having an air layer and absorbing the sound of rain; and a weather-resistant layer 10 provided on a side of the sound absorbing layer opposite a vehicle body.

Description

[Technical Field]

[0001] The present invention relates to an exterior film. [Background technology]

[0002] In recent years, roof panels have become thinner in order to reduce the weight of automobiles and other vehicles. This has made it easier for sounds such as rain to be transmitted into the vehicle interior, and various studies have been conducted to improve the soundproofing performance of the vehicle interior.

[0003] In this regard, for example, Patent Document 1 listed below discloses a configuration in which a foam is disposed on the inner surface side (compartment side) of the vehicle body. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Application Laid-Open No. 2016-203944 Summary of the Invention [Problem to be solved by the invention]

[0005] The inventors discovered that while the configuration in which foam is placed on the inner surface of the vehicle body as described above provides a certain degree of soundproofing performance against external noise and vehicle engine noise, the sound absorption performance against rain noise is still not satisfactory because rain comes into direct contact with the vehicle body.

[0006] The present invention has been made to solve the above problems, and has an object to provide an exterior film that can effectively absorb the sound of rain. [Means for solving the problem]

[0007] The exterior film according to the present invention, which achieves the above object, is an exterior film to be attached to the exterior side of a vehicle body, and includes a sound absorbing layer having an air layer for absorbing rain noise, a weather-resistant layer provided on the opposite side of the sound absorbing layer from the vehicle body, and a colored layer provided between the weather-resistant layer and the sound absorbing layer. weather The weather-resistant layer is a concealing layer that prevents the weather from being seen through the layer. The weather-resistant layer contains a fluorine resin and an acrylic resin. [Effects of the Invention]

[0008] According to the above-mentioned exterior film, rain does not come into direct contact with the vehicle body, but comes into contact with the exterior film located on the exterior side of the vehicle body. Since the exterior film according to the present invention has a sound-absorbing layer, it can effectively absorb rain noise. [Brief explanation of the drawings]

[0009] [Figure 1] 1 is a schematic diagram showing how an exterior film according to the present embodiment is attached to a top panel of an automobile. [Figure 2] 1 is a schematic cross-sectional view showing an exterior film according to an embodiment of the present invention. DETAILED DESCRIPTION OF THE INVENTION

[0010] Hereinafter, an embodiment of the present invention will be described with reference to the accompanying drawings. In the description of the drawings, the same elements are given the same reference numerals, and duplicate explanations will be omitted. Furthermore, the dimensional proportions in the drawings are exaggerated for the convenience of explanation and may differ from the actual proportions.

[0011] In this specification, the range "X to Y" means "X or more and Y or less." Unless otherwise specified, operations and measurements of physical properties are carried out under conditions of room temperature (20 to 25°C) and relative humidity of 45 to 55%.

[0012] Hereinafter, an exterior film 1 according to this embodiment will be described with reference to Fig. 1 and Fig. 2. Fig. 1 is a schematic diagram showing how the exterior film 1 according to this embodiment is attached to a top plate R (corresponding to the vehicle body) of an automobile C. Fig. 2 is a schematic cross-sectional view showing the exterior film 1 according to this embodiment.

[0013] As shown in Fig. 1, the exterior film 1 according to this embodiment is attached to the top plate R of an automobile C. When the exterior film 1 is attached to the top plate R, the release liner 70 is peeled off and the third pressure-sensitive adhesive layer 60 side is attached to the top plate R. Here, when the exterior film 1 is attached, the top plate R of the automobile C may be in a state after having been subjected to an anti-rust electrodeposition coating (primer coating), or may be in a state after having been subjected to an anti-rust electrodeposition coating (primer coating) and having been subjected to an intermediate coat and a top coat.

[0014] As shown in FIG. 2, the exterior film 1 according to this embodiment has, from top to bottom, a weather-resistant layer 10, a first adhesive layer 20, a colored layer 30, a second adhesive layer 40, a sound-absorbing layer 50, a third adhesive layer 60, and a release liner 70.

[0015] The weather-resistant layer 10 is provided for the purpose of improving weather resistance. The sound-absorbing layer includes an air layer that attenuates sound energy. However, if the air layer is blocked by rain or other factors, the sound-absorbing effect is significantly reduced. Therefore, the weather-resistant layer 10 is an essential component for maintaining the effectiveness of the sound-absorbing layer. Examples of resins constituting the weather-resistant layer 10 include well-known resins such as fluororesin, vinyl chloride resin, urethane resin, and acrylic resin, as well as mixed resins containing two or more of these. The weather-resistant layer 10 may be a laminate of resin layers formed by laminating various resin layers. A laminate composed of a fluororesin layer and an acrylic resin layer is particularly preferred as the weather-resistant layer 10. In this laminate, the fluororesin layer ensures antifouling properties and weather resistance, while the acrylic resin layer improves adhesion to the first pressure-sensitive adhesive layer 20. Therefore, in a laminate composed of a fluororesin layer and an acrylic resin layer, the acrylic resin layer is preferably disposed on the first pressure-sensitive adhesive layer 20 side. Furthermore, additives such as ultraviolet absorbers can be easily added to the acrylic resin layer, and the function of the weather-resistant layer 10 can be easily improved.

[0016] Examples of fluororesins include polyvinylidene fluoride, ethylene-tetrafluoroethylene copolymer, ethylene-chlorotrifluoroethylene copolymer, tetrafluoroethylene-perfluoroalkoxyethylene copolymer, tetrafluoroethylene-hexafluoropropylene copolymer, and polychlorotrifluoroethylene.

[0017] The weather-resistant layer 10 preferably has an ultraviolet transmittance of 20% or less on average in the wavelength range of 300 nm to 380 nm. The ultraviolet transmittance can be measured using a spectrophotometer. By setting the ultraviolet transmittance to 20% or less in this way, the amount of ultraviolet light incident on the sound absorbing layer 50 can be reduced, and deterioration of the sound absorbing layer 50 can be suppressed.

[0018] Furthermore, the Young's modulus of the weather-resistant layer 10 is preferably 100 MPa or more and 4000 MPa or less. With this configuration, even if an external force is applied to the exterior film 1 placed outside the vehicle, the sound-absorbing layer 50 is less likely to deform, and therefore, the occurrence of wrinkles in the exterior film 1 can be suppressed.

[0019] By providing the weather-resistant layer 10 in this manner, it is possible to suitably prevent the sound absorbing layer 50 from becoming waterlogged due to rain and losing its sound absorbing function.

[0020] The thickness of the weather-resistant layer 10 is not particularly limited, but is, for example, 30 to 75 μm. For example, if the thickness of the weather-resistant layer 10 is thinner than 30 μm, it may not be able to exhibit suitable weather resistance. Furthermore, if the thickness of the weather-resistant layer 10 is thicker than 75 μm, it may not be able to conform to the curved surface of the tabletop R well, and it may not be possible to attach it to the tabletop R properly.

[0021] The first pressure-sensitive adhesive layer 20 bonds the weather-resistant layer 10 and the colored layer 30. The pressure-sensitive adhesive used in the first pressure-sensitive adhesive layer 20 is not particularly limited, and examples thereof include acrylic pressure-sensitive adhesives, rubber pressure-sensitive adhesives, silicone pressure-sensitive adhesives, urethane pressure-sensitive adhesives, polyester pressure-sensitive adhesives, styrene-diene block copolymer pressure-sensitive adhesives, and vinyl alkyl ether pressure-sensitive adhesives. The above pressure-sensitive adhesives may be used alone or in combination of two or more types.

[0022] As the pressure-sensitive adhesive, an acrylic pressure-sensitive adhesive is particularly suitable from the viewpoint of adhesive reliability. The acrylic polymer constituting the acrylic pressure-sensitive adhesive is formed by using a (meth)acrylic acid alkyl ester having adhesive properties as a main monomer component, and, if necessary, using a monomer copolymerizable with the (meth)acrylic acid alkyl ester (copolymerizable monomer).

[0023] Examples of adhesive (meth)acrylic acid alkyl esters include methyl (meth)acrylate, butyl (meth)acrylate, 2-ethylhexyl (meth)acrylate, octyl (meth)acrylate, etc. These may be used alone or in combination of two or more.

[0024] Specific examples of copolymerizable monomers with alkyl (meth)acrylate esters include carboxyl group-containing monomers such as (meth)acrylic acid, maleic acid, fumaric acid, crotonic acid, itaconic acid, myristoleic acid, palmitoleic acid, and oleic acid; carboxylic acid anhydride group-containing monomers such as maleic anhydride and itaconic anhydride; hydroxyl group-containing monomers such as hydroxyalkyl (meth)acrylates, such as 2-hydroxyethyl (meth)acrylate, 2-hydroxypropyl (meth)acrylate, and 4-hydroxybutyl (meth)acrylate, and glycerin dimethacrylate; vinyl acetate, styrene, and acrylonitrile. These may be used alone or in combination of two or more.

[0025] The weight-average molecular weight of the acrylic polymer is not particularly limited, but is preferably 100,000 to 1,000,000. The weight-average molecular weight is a value measured by gel permeation chromatography (GPC) in terms of polystyrene.

[0026] The pressure-sensitive adhesive preferably contains a crosslinking agent in addition to the acrylic polymer. Examples of the crosslinking agent include an isocyanate crosslinking agent, an epoxy crosslinking agent, and a metal chelate crosslinking agent. The amount of the crosslinking agent added is preferably 0.001 to 10 parts by mass, and more preferably 0.005 to 2.0 parts by mass, per 100 parts by mass of the acrylic polymer.

[0027] If necessary, light stabilizers, antioxidants, colorants, fillers, antistatic agents, tackifiers, wetting agents, leveling agents, thickeners, antifoaming agents, preservatives, etc. may be appropriately added to the first adhesive layer 20.

[0028] The thickness of the first adhesive layer 20 is not particularly limited, but is preferably in the range of 10 to 100 μm from the viewpoint of adhesiveness and thinning.

[0029] The colored layer 30 is a concealing layer that prevents the sound-absorbing layer 50 from being seen through the weather-resistant layer 10. Therefore, it is preferable that the colored layer 30 have a high concealing ratio. To define "concealing ratio" more quantitatively, the concealing ratio of the colored layer 30 according to the present invention is 70% or more. "Concealing ratio" is an index indicating the ability to conceal the color of the base, and is defined by JIS K5600-4-1:1999. After applying the exterior film 1 to the white and black sections of a concealing ratio test paper, the tristimulus values ​​YW and YB of each are measured, and the concealing ratio is calculated as a percentage of the ratio YB / YW. This concealing ratio is preferably 75% or more, and more preferably 78% or more.

[0030] The colored layer 30 can be, for example, a layer containing a black pigment such as carbon black. With such a configuration, the colored layer 30 in the exterior film 1 of this embodiment exhibits black color.

[0031] To quantitatively define a preferred embodiment of "black," the colored layer 30 in the exterior film 1 according to the present invention has a reflection density of 0.5 or greater. "Reflection density" is a type of optical density and is defined as "-log10(reflectance)" using reflectance (=amount of light reflected from a reflective surface / amount of light incident on a reflective surface). For example, when the reflectance is 10%, the reflection density is calculated as (-log10(0.1)) = 1, and when the reflectance is 1%, the reflection density is calculated as (-log10(0.01)) = 2. Conversely, when the reflection density is 0.5 or greater, the reflectance is (1 / 10)1 / 2 (= approximately 31.6%) or less. This reflection density is preferably 0.8 or greater, more preferably 1.0 or greater, even more preferably 1.3 or greater, particularly preferably 1.7 or greater, and most preferably 2.0 or greater.

[0032] In this embodiment, the colored layer 30 is black, and carbon black, which is a type of carbon particle, is added to the colored layer 30 as a means for making the layer black and functioning as a hiding layer. Various types of carbon black are known, including oil furnace black, channel black, lamp black, thermal black, and acetylene black. Any of these may be used in this embodiment. The colored layer is not limited to being black. In addition to the carbon black described above, colorants contained in the colored layer include graphite, copper oxide, manganese dioxide, aniline black, perylene black, titanium black, cyanine black, activated carbon, ferrite (non-magnetic ferrite, magnetic ferrite, etc.), magnetite, chromium oxide, iron oxide, molybdenum disulfide, chromium complexes, composite oxide-based black pigments, and anthraquinone-based organic black pigments.

[0033] There are no particular limitations on the average particle size of the carbon particles used, and any form that can achieve the above-mentioned hiding power (preferably, the hiding power and reflection density) can be appropriately adopted. As an example, the average particle size of the carbon particles is preferably 10 to 100 nm, more preferably 20 to 80 nm, and particularly preferably 25 to 70 nm. The average particle size of the carbon particles can be obtained, for example, by randomly selecting several to several tens of carbon particles from a photograph taken with an electron microscope and calculating the arithmetic mean value of the particle sizes of the selected individual carbon particles (the maximum length connecting any two points on the contour line).

[0034] There are no particular restrictions on the content of the black pigment contained in the colored layer 30, and it can be set appropriately so as to achieve the desired hiding power. For example, the content of the black pigment in the colored layer 30 is preferably 1 to 30 parts by mass, more preferably 5 to 20 parts by mass, and even more preferably 10 to 15 parts by mass, relative to 100% by mass of the solid content constituting the colored layer 30.

[0035] The colored layer 30 preferably contains a binder. Examples of binders that can be used include vinyl chloride resin, acrylic resin, polyester resin, alkyd resin, epoxy resin, and polyurethane resin. These binders can also be used in combination with crosslinking agents such as amino resin, methylolated melamine resin, alkyl etherified melamine resin, urea resin, and polyisocyanate compounds.

[0036] There are no particular restrictions on the amount of binder used, but as an example, the binder content in the colored layer 30 is preferably 3 to 40 parts by mass, more preferably 5 to 35 parts by mass, and even more preferably 10 to 30 parts by mass, per 100 parts by mass of the solid content constituting the colored layer 30.

[0037] The thickness of the colored layer 30 is not particularly limited, but is, for example, 30 to 75 μm.

[0038] The colored layer 30 may contain stabilizers (e.g., Ba-Zn-based, etc.), lubricants, fillers, processing aids, plasticizers, softeners, metal powder, anti-fogging agents, UV shielding agents such as UV scattering agents or UV absorbing agents, antioxidants, antistatic agents, and flame retardants as needed.

[0039] The colored layer may be a printed layer formed on a transparent resin film. Examples of resins that make up the transparent resin film include vinyl chloride resin, acrylic resin, polyester resin, alkyd resin, epoxy resin, and polyurethane resin. The colored layer may also be a printed layer formed on the sound-absorbing layer 50. The printing method is not particularly limited, and the layer may be formed by screen printing, offset printing, flexographic printing, gravure printing, inkjet printing, spray painting, bar coating, or the like. Furthermore, the colored layer may be formed as a film by a calendaring method, extrusion method, solution casting method, or the like.

[0040] The second pressure-sensitive adhesive layer 40 bonds the colored layer 30 and the sound absorbing layer 50. As the second pressure-sensitive adhesive layer 40, the same pressure-sensitive adhesive layer as the first pressure-sensitive adhesive layer 10 can be used.

[0041] The sound absorbing layer 50 has an air layer to absorb rain noise. In this embodiment, the sound absorbing layer 50 is a foam layer.

[0042] The foam layer is formed from a foam such as acrylic foam, vinyl chloride foam, urethane foam, or polyolefin foam such as polyethylene foam. Among these foam layers, urethane foam and / or polyolefin foam are preferred because they further enhance the effects of the present invention.

[0043] As the foam layer, commercially available products may be used, and examples of commercially available products include Calmflex (registered trademark) (manufactured by INOAC Corporation), Sunpelca (registered trademark) (manufactured by Sanwa Kako Co., Ltd.), Toraypef (registered trademark) (manufactured by Toray Industries, Inc.), Softlon (registered trademark) (manufactured by Sekisui Chemical Co., Ltd.), XLIM (manufactured by Sekisui Chemical Co., Ltd.), and Volara (manufactured by Sekisui Chemical Co., Ltd.).

[0044] The foam layer may be either a closed cell foam or an open cell foam, but a closed cell foam is preferred from the viewpoint of preventing water from seeping in from the sides. The foam layer may also be a mixture of closed cell foam and open cell foam.

[0045] The density of the foam layer is, for example, 20 to 350 kg / m 3 is preferably 30 to 100 kg / m 3 It is more preferable that the density of the foam layer is within this range. If the density of the foam layer is within this range, sound absorption can be performed favorably. Here, the density of the foam layer refers to the apparent density measured by a measurement method in accordance with JIS K 7222:2005.

[0046] The thickness of the foam layer is preferably 60 μm to 5 mm. For example, if the foam layer is thinner than 60 μm, the foam layer may not be able to adequately absorb sound. If the foam layer is thicker than 5 mm, it may not be able to adequately conform to the curved surface of the tabletop R and may become waterlogged.

[0047] The third pressure-sensitive adhesive layer 60 is a layer that adheres to the top plate R when the release liner 70 is peeled off.

[0048] The adhesive used in the third adhesive layer 60 can be the same as that used in the first adhesive layer 10. From the viewpoint of adhesive reliability, an acrylic adhesive is particularly suitable for use as the adhesive used in the third adhesive layer 60. The acrylic polymer constituting the acrylic adhesive is formed by using an adhesive (meth)acrylic acid alkyl ester as the main monomer component, and, as necessary, a monomer copolymerizable with the (meth)acrylic acid alkyl ester (copolymerizable monomer). Here, the main component refers to 50% by mass or more of the monomer, preferably 65% ​​by mass or more, and more preferably 85% by mass or more.

[0049] The acrylic polymer is preferably obtained by copolymerizing a monomer mixture containing (A) 100 parts by mass of an alkyl (meth)acrylate ester and (B) 2 parts by mass or more of a carboxyl group-containing vinyl monomer, since this further improves adhesion to vehicle bodies (e.g., steel plates).

[0050] The (meth)acrylic acid alkyl ester is the same as that described above in the section for the first pressure-sensitive adhesive layer.

[0051] Examples of the carboxyl group-containing vinyl monomer include compounds having an ethylenic double bond and a carboxyl group in the same molecule. Specific examples of the carboxyl group-containing vinyl monomer include (meth)acrylic acid, maleic acid, fumaric acid, crotonic acid, itaconic acid, myristoleic acid, palmitoleic acid, and oleic acid. Among these, the carboxyl group-containing vinyl monomer is preferably (meth)acrylic acid, and more preferably acrylic acid.

[0052] The content of the carboxyl group-containing vinyl monomer is preferably 2 parts by mass or more, and more preferably 2 to 15 parts by mass, per 100 parts by mass of the (meth)acrylic acid alkyl ester.

[0053] The monomer copolymerizable with the (meth)acrylic acid alkyl ester (copolymerizable monomer) is also the same as that described in the section for the first pressure-sensitive adhesive layer.

[0054] The weight-average molecular weight of the acrylic polymer used in the third pressure-sensitive adhesive layer 60 is not particularly limited, but is preferably 100,000 to 1,000,000. The weight-average molecular weight is a polystyrene-equivalent value measured by gel permeation chromatography (GPC).

[0055] The glass transition temperature Tg of the acrylic polymer is preferably -50°C or higher. By adjusting the glass transition temperature Tg of the acrylic polymer to -50°C or higher, the gasoline resistance of the pressure-sensitive adhesive layer is improved, and the ability to conform to the curved surface of the vehicle body is also improved. Furthermore, from the viewpoint of adhesiveness, the glass transition temperature Tg of the acrylic polymer is preferably 10°C or lower. The adhesiveness and glass transition temperature can be adjusted by appropriately adjusting the type of monomer used, in particular the type and content of the (meth)acrylic acid alkyl ester, which is the main monomer.

[0056] The glass transition temperature of the acrylic polymer is calculated from the Tgn of each of the constituent polymers constituting the copolymer according to the Fox equation below.

[0057] Fox formula: 1 / Tg = Σ(Wn / Tgn) Tg: Calculated Tg of the polymer (K) Wn: weight fraction of monomer n Tgn: Glass transition temperature (K) of the homopolymer of monomer n

[0058] The Tg value (Tgn) of a homopolymer of monomer n is described, for example, in technical documents from monomer manufacturers such as Nippon Shokubai Co., Ltd., Mitsubishi Chemical Corporation, and Toagosei Co., Ltd., in Polymer Data Handbook (published by Baifukan, edited by the Society of Polymer Science (Basics), first edition January 1986), and in Polymer Handbook 4th edition (J. Brandrup, E. H. Immergut, E. A. Grulke, published in 1999, Wiley-Interscience).

[0059] The method for producing the acrylic polymer is not particularly limited, and conventional methods using a polymerization initiator, such as solution polymerization, emulsion polymerization, suspension polymerization, reverse-phase suspension polymerization, thin-film polymerization, and spray polymerization, can be used. In addition to methods initiating polymerization using a polymerization initiator, methods initiating polymerization by irradiation with radiation, electron beams, ultraviolet rays, etc. can also be used. Among these, solution polymerization using a polymerization initiator is preferred because it facilitates molecular weight control and minimizes impurities. For example, the polymer can be obtained by using ethyl acetate, toluene, methyl ethyl ketone, or the like as a solvent, adding preferably 0.01 to 0.50 parts by mass of the polymerization initiator per 100 parts by mass of the total amount of monomers, and reacting under a nitrogen atmosphere at a reaction temperature of, for example, 60 to 90°C for 3 to 10 hours.

[0060] Examples of the polymerization initiator include azo compounds such as azobisisobutyronitrile (AIBN), 2,2'-azobis(2-methylbutyronitrile), and azobiscyanovaleric acid; organic peroxides such as tert-butyl peroxypivalate, tert-butyl peroxybenzoate, tert-butylperoxy-2-ethylhexanoate, di-tert-butyl peroxide, cumene hydroperoxide, benzoyl peroxide, and tert-butyl hydroperoxide; and inorganic peroxides such as hydrogen peroxide, ammonium persulfate, potassium persulfate, and sodium persulfate. These may be used alone or in combination of two or more.

[0061] A chain transfer agent may be added to the monomer solution to appropriately control the molecular weight of the acrylic polymer. Examples of the chain transfer agent include thiol compounds such as n-dodecyl mercaptan, 2-mercaptoethanol, β-mercaptopropionic acid, octyl β-mercaptopropionate, methoxybutyl β-mercaptopropionate, trimethylolpropane tris(β-thiopropionate), butyl thioglycolate, propanethiols, butanethiols, and thiophosphites, and halogen compounds such as carbon tetrachloride. These may be used alone or in combination of two or more.

[0062] The adhesive used in the third adhesive layer 60 preferably contains a crosslinking agent in addition to an acrylic polymer. Examples of the crosslinking agent include an isocyanate crosslinking agent, an epoxy crosslinking agent, and a metal chelate crosslinking agent. The amount of the crosslinking agent added is preferably 0.001 to 10 parts by mass, and more preferably 0.005 to 2.0 parts by mass, per 100 parts by mass of the acrylic polymer.

[0063] The thickness of the third adhesive layer 60 is not particularly limited, but is preferably in the range of 10 to 100 μm from the viewpoint of adhesiveness and thinning.

[0064] <Release liner 70> The release liner 70 is a member that protects the third pressure-sensitive adhesive layer 60 and prevents a decrease in adhesiveness. The release liner 70 is peeled off from the exterior film 1 when the film is attached to the top panel R of the automobile C. For this reason, the exterior film 1 in this embodiment also includes films that do not have a release liner 70.

[0065] Examples of the release liner 70 include, but are not limited to, plastic films such as polyester films such as polyethylene terephthalate, polybutylene terephthalate, and polyethylene naphthalate, and polyolefin films such as polypropylene and polyethylene; and papers such as fine paper, glassine paper, kraft paper, and clay-coated paper.

[0066] The thickness of release liner 70 is typically about 10 to 400 μm. A layer made of a release agent such as silicone may be provided on the surface of release liner 70 to improve the releasability of third pressure-sensitive adhesive layer 60. When such a layer is provided, the thickness of the layer is typically about 0.01 to 5 μm.

[0067] The method for stretching the exterior film 1 is not particularly limited, but examples include TOM molding, insert molding, press molding, and in-mold molding.

[0068] The above describes the exterior film 1 according to an embodiment of the present invention, but the present invention is not limited to the configuration described in the embodiment and can be modified as appropriate based on the scope of the claims.

[0069] For example, in the above-described embodiment, the sound absorbing layer 50 is a foam layer. However, the sound absorbing layer may be made of a nonwoven fabric. Examples of nonwoven fabrics include spunbond nonwoven fabric, meltblown nonwoven fabric, thermally bonded nonwoven fabric, chemically bonded nonwoven fabric, needle-punched nonwoven fabric, and stitch-bonded nonwoven fabric. Furthermore, the sound absorbing layer may be made of a laminate of multiple types of nonwoven fabric.

[0070] Examples of materials constituting nonwoven fabrics include thermoplastic resins, and specifically, polyolefins, which are homopolymers or copolymers of α-olefins such as ethylene, propylene, 1-butene, 1-hexene, 4-methyl-1-pentene, and 1-octene [ethylene homopolymers such as high-pressure low-density polyethylene, linear low-density polyethylene (LLDPE), high-density polyethylene, ethylene-propylene random copolymers, and ethylene-1-butene random copolymers, or ethylene-α-olefin copolymers; propylene homopolymers (polypropylene), propylene-ethylene random copolymers, propylene-ethylene-1-butene random copolymers (random polypropylene), propylene block copolymers, propylene- Examples of the polymers include propylene polymers such as 1-butene random copolymers; 1-butene polymers such as 1-butene homopolymers, 1-butene-ethylene copolymers, and 1-butene-propylene copolymers; polyolefin polymers such as 4-methyl-1-pentene polymers such as poly4-methyl-1-pentene homopolymers, 4-methyl-1-pentene-propylene copolymers, and 4-methyl-1-pentene-α-olefin copolymers; polyesters (polyethylene terephthalate, polybutylene terephthalate, polyethylene naphthalate, etc.), polyamides (nylon-6, nylon-66, polymetaxylene adipamide, etc.), polyvinyl chloride, polyimide, ethylene-vinyl acetate copolymers, polyacrylonitrile, polycarbonate, and polystyrene.

[0071] The weight of the nonwoven fabric is 20 to 800 g / m from the viewpoint of sound absorption. 2 is preferably 150 to 500 g / m 2 In addition, the bulk density of the nonwoven fabric is 0.01 to 0.5 g / cm from the viewpoint of sound absorption. 3 is preferably 0.05 to 0.2 g / cm 3 is.

[0072] The sound absorbing layer may also be a composite material of the nonwoven fabric and another material (for example, paper). RuBA (registered trademark) (a composite of PET nonwoven fabric and PET specialty paper) can be used as such a composite material.

[0073] In the above-described embodiment, the exterior film 1 has the colored layer 30, but it does not have to have a colored layer. In this case, when the exterior film 1 is attached, it is desirable that the top plate R of the automobile C has been painted with an anti-rust electrodeposition coating.

[0074] In addition, in the above-described embodiment, the first adhesive layer 10 is provided between the weather-resistant layer 10 and the colored layer 30, but when the weather-resistant layer 10 and the colored layer 30 are heat-sealed, the first adhesive layer is not provided.

[0075] In the above-described embodiment, the colored layer 30 is black as an example, but is not limited to this and may be other colors.

[0076] This application is based on Japanese Patent Application No. 2020-171123 filed on October 9, 2020, the disclosure of which is incorporated herein by reference in its entirety. [Explanation of symbols]

[0077] 1 outer film, 10 weatherproof layer, 30 colored layers, 50 soundproof layers, 60 third adhesive layer (adhesive layer), C. Automobiles (vehicles), R Top plate (body).

Claims

1. An exterior film attached to the exterior of a vehicle body, An air layer that absorbs the sound of rain, a weather-resistant layer provided on the opposite side of the sound-absorbing layer from the vehicle body; a colored layer provided between the weather-resistant layer and the sound-absorbing layer, The colored layer is a concealing layer that prevents the sound absorbing layer from being seen through the weather-resistant layer, The weather-resistant layer comprises a fluororesin and an acrylic resin.

2. The sound absorbing layer is a foam layer, The density of the foam layer is 20 to 350 kg / m ３ 2. The exterior film according to claim 1, wherein

3. The exterior film according to claim 1 , wherein the sound absorbing layer is a nonwoven fabric.

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