Sound-insulating laminate body and sound-insulating film used in its manufacture, and sound-insulating film sheet

Abstract

To provide a sound-insulating film that is thin, causes no variation in sound insulating properties depending on a location where the sound insulating properties are measured, and constantly exhibits desired sound insulating properties, and to provide a sound-insulating laminate body using the sound-insulating film, and a sound-insulating film sheet suitable for manufacturing the sound-insulating laminate body.SOLUTION: A sound-insulating laminate body 11 includes at least: a sound-insulating film 2 characterized by containing a resin, metal particles, and cellulose nanofibers; and a sound absorption body 4, wherein the sound-insulating films 2 are formed on both surfaces of the sound absorption body 4.SELECTED DRAWING: Figure 3

Description

[Technical Field]

[0001] The present invention relates to a sound insulation film, a sound insulation film sheet, and a soundproof laminate. [Background technology]

[0002] Conventionally, soundproofing materials with soundproofing properties (the ability to prevent sound transmission) have been developed using sound-insulating materials with sound-insulating properties (the ability to reflect sound and prevent it from transmitting) and sound-absorbing materials with sound-absorbing properties (the ability to convert the kinetic energy of sound into thermal energy and attenuate it). For example, sound-insulating materials include sound-insulating sheets made from heavy materials with high specific gravity such as steel plates, and sound-absorbing materials include porous sound-absorbing materials with cushioning properties that are foamed by adding a foaming agent to a resin. Also known are soundproofing materials that combine these sound-insulating and sound-absorbing materials. These soundproofing materials are used on the walls of buildings, in moving objects such as automobiles, and in electronic devices.

[0003] However, when attempting to obtain sufficient soundproofing using conventional sound-insulating materials, in accordance with the mass law, sufficient soundproofing was sometimes not obtained unless heavy materials were used. Furthermore, conventional porous sound-absorbing materials alone were sometimes unable to provide sufficient soundproofing. Particularly in recent years, with the widespread use of electric vehicles, there has been a demand for lighter vehicles to improve energy efficiency. As automobiles become lighter, there is a demand to replace steel plates with lighter soundproofing materials in terms of weight. Furthermore, from the perspective of design freedom, soundproofing materials that are flexible enough to conform to three-dimensional shapes are considered preferable.

[0004] Patent Document 1 discloses a soundproof sheet formed by integrally bonding a first sheet member made of one of paper, cloth, nonwoven fabric, metal foil, and resin sheet, which are used for sound insulation panels, vibration damping materials, etc., and a second sheet member (soundproofing film) formed into a sheet by mixing metal powder with an organic binder. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] Patent Publication No. 7-266488 Summary of the Invention [Problem to be solved by the invention]

[0006] The soundproof sheet described in Patent Document 1 was lighter than steel plates and exhibited a certain level of soundproofing. However, when making the second sheet member (soundproofing film) thinner to reduce its weight, it was difficult to achieve a uniform thickness using conventional sheet-forming methods such as rolling. Furthermore, when mixing only metal particles with an organic binder and rolling the mixture, the metal particles sometimes localized. Another method for thinning a soundproofing film involves adding a dilution solvent and forming the film by a coating method. However, even with this coating method, there are drawbacks: the metal particles precipitate in the resin, resulting in inconsistent dispersion in the soundproofing film; the film cannot be formed to a uniform thickness; or the soundproofing film may be formed without any metal particles present. Therefore, the resulting soundproofing film has the drawback of varying in soundproofing properties depending on the location where the soundproofing properties are measured, and does not always exhibit the desired soundproofing properties. An object of the present invention is to provide a thin soundproofing film that does not cause variation in soundproofing properties depending on the location where the soundproofing properties are measured and that always exhibits the desired soundproofing properties, a soundproofing laminate using the same, and a soundproofing film sheet that is suitable for producing a soundproofing laminate. [Means for solving the problem]

[0007] The present invention comprises the following aspects: (Section 1) A sound-insulating film containing at least resin, metal particles, and cellulose nanofibers.

[0008] By using the sound-insulating film according to Item 1, the inclusion of cellulose nanofibers in the sound-insulating film allows the metal particles to be uniformly and stably dispersed in the sound-insulating film, making it possible to impart sound-insulating properties to the sound-insulating film without variation, and further enabling continuous processing using a roll-to-roll method. Therefore, the sound-insulating film of the present invention has excellent productivity. By using the sound-insulating film of the present invention, the sound-insulating properties of the sound-insulating film can be easily imparted to the sound-insulating laminate of the present invention described below, and in combination with the sound-absorbing properties of the sound-absorbing body, the sound-insulating properties of the sound-insulating laminate can be further improved.

[0009] (Section 2) A soundproof laminate comprising at least one or more layers of sound absorbing material and two or more layers of sound insulating film, the soundproof laminate having at least a structure in which the sound insulating film is formed on both sides of the sound absorbing material including the one or more layers of sound absorbing material, and the sound insulating film is the sound insulating film according to item 1.

[0010] By using the soundproof laminate described in item 2, it is possible to impart excellent sound insulation to the sound absorbing material, and to improve the soundproofing properties of the soundproof laminate.

[0011] (Section 3) Item 1. A sound insulation film sheet having at least the sound insulation film according to Item 1 formed on a substrate.

[0012] The sound insulation film of the present invention can be easily formed on a sound absorber by using the sound insulation film sheet described in item 3. Therefore, the sound insulation laminate of the present invention can be easily obtained by using the sound insulation film sheet of the present invention. [Effects of the Invention]

[0013] The sound-insulating film of the present invention is characterized by containing at least a resin, metal particles, and cellulose nanofibers. Therefore, when the film is applied to a substrate described below, the metal particles do not settle in the resin, and the metal particles are uniformly dispersed in the sound-insulating film, and the film can be formed with a uniform thickness. Therefore, the obtained sound-insulating film is thin and does not vary in sound-insulating properties depending on the location where it is measured, resulting in a sound-insulating film that always exhibits the desired sound-insulating properties. A sound-insulating laminate using the sound-insulating film of the present invention also always exhibits the desired sound-insulating properties. Furthermore, the sound-insulating laminate of the present invention can be easily obtained by using the sound-insulating film sheet of the present invention. [Brief explanation of the drawings]

[0014] [Figure 1] 1 is a schematic diagram of a cross-sectional structure of one embodiment of a sound insulation film sheet of the present invention in which a sound insulation film is formed on a substrate. [Figure 2] FIG. 1 is a schematic diagram of the cross-sectional structure of one embodiment of the soundproof laminate of the present invention, in which sound-insulating film sheets (substrate / sound-insulating film) are formed on two opposing surfaces (both surfaces) of a sound absorber (one layer of sound-absorbing material). [Figure 3] FIG. 1 is a schematic diagram of the cross-sectional structure of one embodiment of the soundproof laminate of the present invention, in which sound-insulating films are formed on two opposing surfaces (both surfaces) of a sound absorber (one layer of sound-absorbing material). [Figure 4] 1 is a schematic diagram of a cross-sectional structure of one embodiment of a soundproof laminate of the present invention in which a plurality of sound absorbers (each of which has one layer of sound-absorbing material) and a plurality of sound-insulating films are formed. DETAILED DESCRIPTION OF THE INVENTION

[0015] (soundproof laminate) The soundproof laminate of the present invention has sound-insulating films, which will be described later, formed on at least two opposing surfaces (both surfaces) of a sound-absorbing body, which will be described later. By forming a laminate having such a configuration, sound can be efficiently absorbed within the sound-absorbing body sandwiched between the two sound-insulating films, and an excellent soundproofing effect can be obtained. In the following, the adhesive layer, which will be described later, may be omitted, and the soundproof laminate may be schematically described as "sound-insulating film / sound-absorbing body / sound-insulating film."

[0016] The method for bonding the sound-insulating film of the present invention to the sound-absorbing body is not particularly limited as long as it is a method that can bond the sound-insulating film of the present invention to the sound-absorbing body, but a method in which the sound-insulating film of the present invention is bonded to the sound-absorbing body via an adhesive layer is preferred because it allows for easy bonding. Alternatively, the sound insulating film and the sound absorbing body may be bonded to each other by a method such as thermocompression bonding without using an adhesive layer.

[0017] The soundproof laminate of the present invention has at least a first sound-insulating film formed on a first surface of a sound absorber, and a second sound-insulating film formed on a second surface of the sound absorber opposite the first surface. That is, sound-insulating films are formed on both surfaces of the sound absorber. The soundproof laminate of the present invention can have, for example, the following configurations: ·Sound insulation film / sound absorber (sound absorbing material) / sound insulation film ·Base material / sound insulation film / sound absorber (sound absorbing material) / sound insulation film / base material ·Sound insulation film / adhesive layer / sound absorber (sound absorbing material) / adhesive layer / sound insulation film ·Sound insulation film / sound absorber (sound absorbing material / sound absorbing material) / sound insulation film ·Sound insulation film / sound absorbing body (sound absorbing material / adhesive layer / sound absorbing material) / sound insulation film ·Sound insulation film / sound absorber (sound absorbing material) / sound insulation film / sound absorbing material (sound absorbing material) ·Sound insulation film / sound absorber (sound absorbing material) / sound insulation film / sound absorbing material (sound absorbing material) / sound insulation film Among the above-mentioned exemplary configurations, in order for the soundproof laminate of the present invention to have excellent soundproofing properties, a configuration in which the sound-insulating film of the present invention is formed on at least the first surface and the second surface opposite the first surface of the sound-absorbing body, i.e., on both surfaces, is preferred. The sound-insulating films, sound-absorbing materials, and sound-absorbing bodies may be made of the same material or different materials, and in addition to these, the soundproofing properties for a specific frequency (for example, sounds of 1000 Hz or less) can be improved by changing the composition of the sound-insulating film, the thickness of the sound-insulating film, the number of sound-absorbing materials, the type of sound-absorbing material, or a combination thereof.

[0018] (Adhesive layer) The adhesive layer is a layer formed between the sound-insulating film of the present invention and the sound-absorbing material in order to bond the sound-insulating film of the present invention to the sound-absorbing material. The adhesive layer may be an adhesive layer made of a conventionally known resin. Examples of resins used in the adhesive layer include polyamide-based resins (nylon-based), acrylic-based resins, chlorinated polypropylene-based resins, vinyl chloride acetate-based resins, and polyester-based resins. When the adhesive layer is made of a resin, it may be formed on either or both the sound-insulating film side and the sound-absorbing material side. Alternatively, an adhesive interlining in which the above-mentioned resin has been sprayed onto a nonwoven fabric or the like in advance may be used as the adhesive layer.

[0019] (functional layer) In addition, the soundproof laminate of the present invention may be formed with one or more layers (functional layers) having any desired function, such as a printed layer, a metal vapor deposition layer, a design layer, or a protective layer, as long as the layer is consistent with the object of the present invention. The material used for the functional layer, the thickness of the functional layer, and the position where the functional layer is formed may be appropriately selected within a range that meets the object of the present invention.

[0020] (sound insulation membrane) The sound-insulating film of the present invention comprises at least a resin, metal particles, and cellulose nanofibers. Furthermore, known additives such as dispersants, viscosity modifiers, stabilizers, dyes, and pigments can be added within a range that does not impair the effects of the present invention. The thickness of the sound-insulating film is preferably 5 μm to 100 μm, and more preferably 20 μm to 80 μm. If the thickness of the sound-insulating film of the present invention is thinner than 5 μm, sufficient sound insulation may not be obtained. If the thickness of the sound-insulating film of the present invention is thicker than 100 μm, the metal particles may not be uniformly dispersed in the sound-insulating film of the present invention.

[0021] (resin) The resin used in the sound-insulating film of the present invention serves as a binder for holding the metal particles, and any of various conventionally known resins that can be processed into a thin film can be used. To achieve the effects of the present invention, thermoplastic resins such as urethane resins, olefin resins, acrylic resins, and epoxy resins are suitable, and urethane resins are particularly suitable from the standpoint of flexibility.

[0022] (metal particles) The metal particles used in the sound-insulating film of the present invention may have any shape, such as spherical, flake-like, or irregular. The particle size of the metal particles may be 1 μm to 50 μm, or may be 2 μm to 40 μm. If the particle size of the metal particles is smaller than 1 μm, the metal particles will be expensive, and there is a risk that the cost of producing the sound-insulating film of the present invention will be too high. If the particle size of the metal particles is larger than 50 μm, there is a risk that the metal particles will not be sufficiently dispersed when producing the sound-insulating film of the present invention. Materials that can be used for the metal particles used in the sound-insulating film of the present invention include particles of conventionally known metals such as aluminum, iron, lead, tungsten, copper, silver, and silicon, or metal compounds such as silicon oxide, iron oxide, and silicon carbide, or mixtures thereof (e.g., stainless steel). In particular, using a metal with high density can improve the sound insulation properties of the sound-insulating film of the present invention. Metal particles made of iron, lead, tungsten, copper, or silver are preferred as the metal particles of the present invention, and metal particles made of iron or tungsten are particularly preferred from the standpoints of cost and ease of handling. The amount of metal particles is preferably 100 to 2,000 parts by mass, more preferably 500 to 1,500 parts by mass, per 100 parts by mass of resin. If the amount is less than 100 parts by mass, soundproofing properties at frequencies of 2,000 Hz or less may be weakened. If the amount is more than 2,000 parts by mass, the flexibility of the film may be impaired, resulting in a brittle film.

[0023] (Cellulose nanofiber) The cellulose nanofibers used in the sound-insulating film of the present invention serve as a dispersant for uniformly dispersing metal particles in the sound-insulating film. By incorporating cellulose nanofibers, metal particles can be uniformly and stably dispersed in the sound-insulating film. Therefore, the resulting sound-insulating film is thin and does not exhibit variations in soundproofing properties depending on the measurement location, resulting in a sound-insulating film that consistently exhibits the desired sound-insulating properties. Furthermore, the sound-insulating film of the present invention can be continuously produced using a roll-to-roll process. Conventional cellulose nanofibers can be used as the cellulose nanofibers used in the sound-insulating film of the present invention. In particular, lignocellulose nanofibers containing lignin are preferred from the standpoint of dispersibility. Conventional cellulose nanofibers with a fiber width of approximately 3 to 200 nm and a fiber length of approximately 100 μm or less can be used. The amount of cellulose nanofiber is preferably 10 to 40 parts by mass, more preferably 20 to 30 parts by mass, per 100 parts by mass of resin. If the amount is less than 10 parts by mass, depending on the amount and particle size of the metal particles, the metal particles may not be sufficiently dispersed. If the amount is more than 40 parts by mass, the flexibility of the film may be impaired, resulting in a brittle film.

[0024] (composition) The composition of the present invention is prepared by adding a conventionally known solvent to at least the resin, metal particles, and cellulose nanofibers described above to prepare a state suitable for a coating method. The composition is formed into a thin film by a coating method or the like and dried to produce the sound-insulating film of the present invention. As described above, by using the composition to produce a sound-insulating film by a coating method, the metal particles can be uniformly and stably dispersed in the sound-insulating film. Therefore, the sound-insulating film and soundproof laminate of the present invention can have uniform sound-insulating properties and can be produced with good productivity.

[0025] (Sound insulation film formation) In order to form the sound-insulating film of the present invention into a thin film, a method (coating method) of applying the above-mentioned composition onto a substrate described below can be mentioned. By using a coating method, the sound-insulating film of the present invention can be easily formed into a thin film. As the coating method, for example, a conventionally known coating method such as a die coating method, a gravure coating method, or a reverse coating method can be used. Furthermore, the coating method may be a batch method or a roll-to-roll method, but the roll-to-roll method is particularly preferred because it allows the sound-insulating film to be produced continuously and is excellent in productivity.

[0026] (sound absorbing body) The sound-absorbing material used in the soundproof laminate of the present invention may be any material that exhibits sound-absorbing properties. The sound-absorbing material of the present invention includes one or more layers of sound-absorbing material. When the sound-absorbing material includes two or more layers of sound-absorbing material, different or the same types of sound-absorbing materials are laminated together by, for example, bonding via an adhesive layer, bonding by thermocompression, or simply overlapping them. The sound-absorbing material may be, for example, a conventionally known sound-absorbing material such as chip cushion, glass wool, rock wool, porous urethane, or polyester fiber. The thickness, material, and shape of the sound-absorbing material and sound-absorbing material may be selected appropriately depending on the purpose for which the soundproof laminate of the present invention is used.

[0027] (sound insulation sheet) The sound insulation film sheet of the present invention comprises at least the sound insulation film of the present invention formed on a substrate, and by laminating the sound insulation film sheet of the present invention on the sound absorbing material, the sound insulation film of the present invention can be easily and productively formed on the sound absorbing material. It is also used to easily obtain the soundproof laminate of the present invention. The sound insulation film sheet of the present invention may contain the above-mentioned functional layer to the extent that it meets the object of the present invention. By using the sound insulation film sheet of the present invention having the functional layer formed thereon, the functional layer can be formed on the sound absorbing material at the same time as the sound insulation film of the present invention, and the soundproof laminate of the present invention having the functional layer can be easily obtained. When the substrate described below is a substrate without releasability, the soundproof laminate of the present invention obtained using the sound insulation film sheet of the present invention has the substrate formed on the sound absorber together with the sound insulating film, as shown in Figure 2. When the substrate described below is a substrate with releasability, the soundproof laminate of the present invention obtained using the sound insulation film sheet of the present invention has the sound insulating film alone formed on the sound absorber, as shown in Figure 3, by removing the substrate from the sound insulation film sheet.

[0028] (base material) The substrate used in the sound insulation film sheet of the present invention may be any substrate to which the composition can be applied. Conventional substrates such as plastic films, nonwoven fabrics, and paper can be used, but plastic films are preferred from the viewpoint of processability. The thickness, material, and other properties of the substrate may be appropriately selected depending on the purpose. As described above, when the substrate is a releasable substrate, the sound insulation film can be transferred onto the sound absorber by removing the substrate after forming the sound insulation film sheet of the present invention on the sound absorber. At this time, any of the functional layers described above can be transferred simultaneously. By transferring the sound insulation film from the sound insulation film sheet onto the sound absorber, the soundproof laminate of the present invention does not include a substrate and can be made lighter. The releasable substrate may also be a substrate on which a release layer having release properties, such as a silicone-based resin layer, a fluorine-based resin layer, a wax layer, or a melamine-based resin layer, is formed. In this case, the release layer is removed along with the substrate when the sound insulation film of the present invention is transferred and formed on the sound absorber, and is not formed on the sound absorber. [Example]

[0029] The present invention will be described in detail below with reference to examples, but the technical scope of the present invention is not limited to the following examples.

[0030] (Preparation of composition for obtaining sound insulation film) (Composition A) A polyurethane resin was used as the resin, and 100 parts by mass of the resin were mixed with 1,000 parts by mass of iron (Fe) particles having a median diameter of 4 to 8 μm as the metal particles, 30 parts by mass of lignocellulose nanofibers (aspect ratio 525, fiber length 45 μm) as the cellulose nanofibers, a diluting solvent, and a stabilizer to obtain composition A for obtaining the sound-insulating film of the present invention.

[0031] (Composition B~G) Compositions B to G were obtained in the same manner as composition A, except that the aspect ratio, fiber length, and amount of the cellulose nanofibers in composition A, and the material and amount of the metal particles were changed as shown in Table 1. The tungsten (W) particles used in composition F had a median diameter of 2 to 9 μm. [Table 1]

[0032] (Creating soundproofing membrane sheets) (Examples 1 to 8 and Comparative Example 1) A 50 μm-thick, 1100 mm-wide polyethylene terephthalate film was used as the substrate, with a 1 μm-thick release layer made of a melamine-based resin. Composition A was continuously applied to the release layer using a roll-to-roll die coating method and dried to form a 50 μm-thick sound-insulating film of the present invention, thereby obtaining a sound-insulating film sheet of Example 1 of the present invention. Furthermore, sound-insulating film sheets of Examples 2 and 3 of the present invention were obtained by forming sound-insulating films in the same manner as Example 1, except that the thickness of the sound-insulating film of Example 1 was changed as shown in Table 2. Furthermore, sound-insulating film sheets of Examples 4 to 8 of the present invention and Comparative Example 1 were obtained by forming sound-insulating films in the same manner as Example 1, except that compositions B to G were used instead of composition A. In the sound-insulating film sheet of Comparative Example 1, iron particles precipitated in the composition, resulting in a sound-insulating film made only of a polyurethane-based resin with no iron particles present in the sound-insulating film. The sound-insulating laminate was not produced or evaluated using the sound-insulating film sheet of Comparative Example 1.

[0033] (Creating soundproof laminates) The sound-proofing laminate of the present invention was obtained using the sound-proofing film sheets obtained in each of the above Examples by the following procedure. First, a double-sided adhesive interlining (adhesive layer) made of a nylon-based resin was placed between the sound-proofing film of the sound-proofing film sheet and a 10 mm-thick chip cushion, which was a sound-absorbing material, and the two were thermocompression-bonded to form a sound-proofing film sheet on the sound-absorbing material. Then, the substrate of the sound-proofing film sheet was removed. A sound-proofing film was similarly formed on the other side of the sound-absorbing material, and the sound-proofing laminate of the present invention of Examples 1 to 8, which had a layer structure of sound-proofing film / adhesive layer / sound-absorbing material / adhesive layer / sound-proofing film, was obtained. Furthermore, in Example 1-2, a double-sided adhesive interlining made of a nylon-based resin was placed between the side of one of the sound-proofing films of Example 1, on which no sound-absorbing material was formed, and the same 10 mm-thick chip cushion, which was a second sound-absorbing material, and the two were thermocompression-bonded. Furthermore, a sound-insulating film was formed on the side of the second sound-absorbing material on which the sound-insulating film was not formed, in the same manner as in Example 1, to obtain the soundproof laminate of the present invention of Example 1-2, which has a laminate structure of sound-insulating film / sound-absorbing material / sound-insulating film / (second) sound-absorbing material / sound-insulating film.

[0034] (Soundproofing evaluation - Transmission loss) For the soundproof laminates of Examples 1 to 8 and 1-2 obtained above, the normal incidence sound transmission loss was measured using a 102 mm diameter acoustic tube (WinZac MTX manufactured by Nihon Onkyo Engineering Co., Ltd.) by the 16-microphone method to evaluate the soundproofing properties. Furthermore, as Comparative Example 2, a sound-insulating material consisting only of a 0.8 mm thick iron plate was used. As Comparative Example 3, a sound-absorbing material consisting only of a 10 mm thick chip cushion was used. The soundproofing properties were evaluated as follows. The results for each example and each comparative example are shown in Table 2. Note that the measurement results in Table 2 were obtained by using the center in the width direction at the end of processing in the length direction of the sound insulation film sheet for the soundproof laminates of Examples 1 to 8 and 1-2. (Soundproofing evaluation criteria) Transmission loss at frequencies of 500Hz, 1000Hz, 2000Hz and 4000Hz is ○: 10dB or more at all frequencies. △: 10 dB or more at any frequency. ×: Less than 10 dB at any frequency.

[0035] (Weight rating - areal density) The weights of samples cut into circular shapes with a diameter of 102 mm were measured and the areal density (kg / m2) was calculated for the soundproof laminates of Examples 1 to 8 and 1-2, the sound-insulating material of Comparative Example 2, and the sound-absorbing material of Comparative Example 3 obtained above. The results are shown in Table 2.

[0036] (Evaluation of processing suitability) Compositions A to F were used and continuously applied by a roll-to-roll method to obtain sound insulation film sheets of Examples 1 to 8, each with a coating width of 1050 mm (substrate 1100 mm) and a length of 50 m. The sound insulation film of the present invention was formed in which metal particles (iron particles or tungsten particles) were uniformly dispersed in the sound insulation film in both the length and width directions. Furthermore, as mentioned above, in the sound insulation film sheet of Comparative Example 1, which used Composition G, the metal particles precipitated in the composition, resulting in a sound insulation film consisting only of polyurethane resin with no iron particles present in the sound insulation film, and the desired sound insulation properties were clearly not achieved. [Table 2]

[0037] As shown in Table 2, the soundproofing laminate of the present invention had a lower surface density, i.e., was lighter, than the soundproofing material of Comparative Example 2. Furthermore, a greater transmission loss was achieved compared to the sound-absorbing material alone of Comparative Example 3, i.e., it exhibited superior soundproofing properties. Compositions A to F for producing the soundproofing film of the present invention contain cellulose nanofibers, which allows the metal particles to be uniformly and stably dispersed. Therefore, even when continuous coating is performed using a roll-to-roll method, the soundproofing film of the present invention in which the metal particles are uniformly dispersed can be continuously produced. Therefore, the soundproofing film sheet of the present invention has excellent productivity. Furthermore, the soundproofing laminate of the present invention can be easily produced by using the soundproofing film sheet of the present invention to produce the soundproofing laminate of the present invention. [Explanation of symbols]

[0038] 1 Base material 2. Sound insulation membrane 3 Adhesive layer 4 sound absorber (1 layer of sound absorbing material) 10 Sound insulation membrane sheet 11 Soundproof laminate

Claims

1. A sound-insulating film containing at least resin, metal particles, and cellulose nanofibers.

2. A soundproof laminate comprising at least one layer of sound absorbing material and two or more layers of sound insulating film, A soundproof laminate having at least a structure in which sound-insulating films are formed on both sides of a sound-absorbing body containing one or more layers of sound-absorbing material, wherein the sound-insulating films are the sound-insulating films according to claim 1.

3. A sound insulation film sheet comprising at least the sound insulation film according to claim 1 formed on a substrate.

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