Laminate, sound absorbing material, and automotive interior member

Abstract

Provided are a laminate, a sound absorbing material, and an automotive interior member which are easy to recycle and have sufficient sound absorbing properties. One embodiment of the present invention is a laminate (10). The laminate (10) includes a resin fiber layer (20) formed from a hot-melt resin, and a base material (30). The hot-melt resin is an olefin-based hot-melt resin, and the material of the base material (30) is an olefin-based resin. The resin fiber layer (20) is formed by spraying the hot-melt resin onto the base material (30).

Description

Laminate, sound-absorbing material, and automobile interior component

[0001] The present invention relates to a laminate, a sound-absorbing material, and an automobile interior component.

[0002] Noise (external noise and noise caused by vibrations during driving) can enter the interior of an automobile through the inside of the doors and the body frame. To suppress this noise, sound-absorbing materials are placed on the backside of automobile interior components such as pillars.

[0003] In recent years, efforts to address environmental issues have led to a demand for recyclability of automotive parts, including sound-absorbing materials. Generally, sound-absorbing materials are manufactured by bonding a resin fiber layer made of nonwoven fabric or the like to a substrate with double-sided tape or the like. Recycling such sound-absorbing materials requires a process of separating the substrate and the resin fiber layer for component sorting, which is a complicated process.

[0004] Therefore, Patent Document 1 discloses a technique for manufacturing a sound-absorbing material by integrating a substrate and a resin fiber layer made of the same material by welding.

[0005] Japanese Patent Application Publication No. 10-232681

[0006] However, while the technology of Patent Document 1 eliminates the need for a process of separating the substrate and the resin fiber layer during recycling, it has problems in that the sound absorption properties of the welded portions are insufficient.Furthermore, there are problems in that the locations that can be welded are limited depending on the shape of the substrate.

[0007] Therefore, an object of the present invention is to provide a laminate, a sound-absorbing material, and an automobile interior component that are easily recyclable and have sufficient sound absorption properties.

[0008] The present inventors have conducted extensive research and found that the above-mentioned problems can be solved by a laminate having a structure (layer) formed from specific components, and have thus completed the present invention. That is, the present invention is as follows.

[0009] One aspect of the present invention is a laminate, which includes a resin fiber layer formed from a hot melt resin and a substrate, wherein the hot melt resin is an olefin-based hot melt resin, the substrate is made of an olefin-based resin, and the resin fiber layer is formed by spray-coating the hot melt resin onto the substrate.

[0010] Another aspect of the present invention is a laminate, comprising a resin fiber layer formed of a hot melt resin and a substrate, wherein the hot melt resin is an olefin-based hot melt resin, the substrate is made of an olefin-based resin, and the adhesive area between the resin fiber layer and the substrate is 10% or more.

[0011] Yet another aspect of the present invention is a sound-absorbing material comprising the laminate of any one of the above aspects.

[0012] Yet another aspect of the present invention is an automobile interior member comprising the laminate of any one of the above aspects.

[0013] According to the present invention, it is possible to provide a laminate, a sound-absorbing material, and an automobile interior component that are easily recyclable and have sufficient sound absorption properties.

[0014] Fig. 1 is a conceptual side view of a laminate according to this embodiment. Fig. 2 is a cross-sectional view schematically showing a conventional laminate (Fig. 2(a)) formed by welding and a laminate according to this embodiment (Fig. 2(b)) in which ribs (protrusions) are formed on a substrate.

[0015] The laminate, sound-absorbing material, and automobile interior components will be specifically described below, but the present invention is not limited to these.

[0016] In this specification, when multiple upper limit values ​​and multiple lower limit values ​​are separately described, all numerical ranges that can be set by freely combining these upper limit values ​​and lower limit values ​​are considered to be described in this specification.

[0017] In this specification, the term "spray application" refers to spraying a molten hot melt resin in the form of fibers using air pressure.

[0018] 1. Structure of the Laminate Figure 1 is a conceptual side view of a laminate 10 according to this embodiment. As shown in Figure 1, the laminate 10 includes a resin fiber layer 20 and a substrate 30. Each component will be described below.

[0019] 1-1. Resin fiber layer 1-1-1. Components The resin fiber layer 20 is a fiber structure formed from a hot melt resin (also called a hot melt adhesive). The resin fiber layer 20 (hot melt resin) is fused onto the substrate 30, thereby fixing the resin fiber layer 20 to the substrate 30.

[0020] The hot melt resin contains a thermoplastic resin component as a main component, and may also contain other components.

[0021] 1-1-1-1. Thermoplastic Resin Component The thermoplastic resin component that is the main component of the hot melt resin that constitutes the resin fiber layer 20 can be polyolefin. That is, the thermoplastic resin component is preferably an olefin-based hot melt resin. Using an olefin-based hot melt resin as the thermoplastic resin component can improve the sound absorption properties and workability of the fiber structure.

[0022] Examples of polyolefins include polyethylene, polypropylene, polybutene-1, ethylene-propylene copolymers, ethylene-α-olefin copolymers, and polymer blends of these.

[0023] The polyolefin is more preferably polypropylene. Polypropylene solidifies in a relatively short time after being fused to the substrate 30, and therefore is more suitable for forming the resin fiber layer 20 because it can easily stably hold the fiber structure.

[0024] 1-1-1-2. Other Components Examples of other components include known additives such as tackifiers, plasticizers, fillers, pigments, dyes, antioxidants, antioxidants, antistatic agents, flame retardants, antibacterial agents, light stabilizers, stabilizers, dispersants, solvents, hydrophilicity-imparting agents, waxes, and crystal nucleating agents.

[0025] The amount of other components can be, for example, 30 parts by mass or less, 20 parts by mass or less, 10 parts by mass or less, 5 parts by mass or less, 1 part by mass or less, or 0.1 parts by mass or less per 100 parts by mass of the hot melt resin.

[0026] 1-1-2. Physical Properties / Characteristics 1-1-2-1. Melt Viscosity The melt viscosity at 180°C of the hot melt resin constituting the resin fiber layer 20 is preferably 200,000 mPa·s or less, 100,000 mPa·s or less, 50,000 mPa·s or less, 30,000 mPa·s or less, or 20,000 mPa·s or less.

[0027] The melt viscosity of the hot melt resin at 180° C. is preferably 1,000 mPa·s or more, 2,000 mPa·s or more, or 5,000 mPa·s or more.

[0028] The melt viscosity at 200° C. of the hot melt resin constituting the resin fiber layer 20 is preferably 100,000 mPa·s or less, 50,000 mPa·s or less, 25,000 mPa·s or less, 20,000 mPa·s or less, or 18,000 mPa·s or less.

[0029] The melt viscosity of the hot melt resin at 200°C is preferably 500 mPa·s or more, 1,000 mPa·s or more, 1,500 mPa·s or more, or 3,000 mPa·s or more.

[0030] By setting the melt viscosity of the hot melt resin within this range, it is easy to spray-apply the hot melt resin and to obtain a resin fiber layer 20 with excellent sound absorbing properties.

[0031] The melt viscosity is measured for a hot melt resin heated to a predetermined temperature using a parallel plate rheometer at an oscillation angle of 10% and an angular frequency of 1 rad / s.

[0032] 1-1-2-2. Crystallization Temperature / Crystallization Energy The crystallization temperature of the hot melt resin constituting the resin fiber layer 20 is preferably 50 to 150° C., 75 to 140° C., or 90 to 135° C. By setting the temperature in such a range, it is possible to improve ease of workability, sound absorption, and the like in a balanced manner.

[0033] The crystallization energy (heat of crystallization) of the hot melt resin is preferably 20 to 200 mJ / mg, 60 to 150 mJ / mg, or 70 to 100 mJ / mg, which allows for a balanced improvement in workability, sound absorption, and the like.

[0034] The crystallization temperature and crystallization energy are measured in accordance with JIS K 7121.

[0035] 1-1-2-3. Storage Modulus, Loss Modulus, Loss Tangent, and Glass Transition Temperature The lower limit of the storage modulus G' of the hot-melt resin is preferably 10 MPa or more, 20 MPa or more, 50 MPa or more, 75 MPa or more, 90 MPa or more, 100 MPa or more, 200 MPa or more, or 500 MPa or more. The upper limit of the storage modulus G' of the hot-melt resin is, for example, 2,000 MPa or less, 1,500 MPa or less, 1,000 MPa or less, or 900 MPa or less.

[0036] The loss modulus G'' of the hot melt resin is preferably 50 MPa or less, or 40 MPa or less.

[0037] The loss tangent tan δ (loss modulus G″ / storage modulus G′) of the hot melt resin is preferably 1.00 or less, or 0.50 or less.

[0038] The hot melt resin preferably has a glass transition temperature of -30 to 60°C, or -25 to 40°C.

[0039] The storage modulus G' and loss modulus G'' are measured as follows: Measurement method: Rheometer Device name: MCR302 (Anton Paar) Oscillation angle: 0.8° Frequency: 10 Hz Deformation mode: Shear mode Temperature: -50 to 110°C Sample size: Width 5 mm x 20 mm x thickness 1 mm The storage modulus G' and loss modulus G'' are values ​​at 23°C.

[0040] The temperature corresponding to the peak value of the loss tangent tan δ is defined as the glass transition temperature.

[0041] By setting the storage modulus G′, loss modulus G″, loss tangent tanδ, or glass transition temperature of the hot melt resin within these ranges, it is easy to obtain a resin fiber layer 20 that has excellent sound absorption properties, shape retention properties, ease of workability, etc.

[0042] In particular, by setting the storage modulus G' of the hot melt resin within this range, it is easy to obtain a resin fiber layer 20 that has higher sound absorption properties and is extremely excellent in shape retention.

[0043] 1-1-2-4. Air permeability The air permeability of the resin fiber layer 20 is 10.0 cm ３ / cm ２ / s or more, 15.0cm ３ / cm ２ / s or more, 20.0cm ３ / cm ２ / s or more, 30.0cm ３ / cm ２ / s or more, 40.0cm3 / cm ２ / s or more, or 45.0 cm ３ / cm ２ / s or more, or 55.0 cm ３ / cm ２ / s or more is preferable.

[0044] The resin fiber layer 20 has an air permeability of 200 cm ３ / cm ２ / s or less, 150cm ３ / cm ２ / s or less, 100cm ３ / cm ２ / s or less, 95.0cm ３ / cm ２ / s or less, 85.0cm ３ / cm ２ / s or less, or 80.0 cm ３ / cm ２ By setting the air permeability of the resin fiber layer 20 in this range, excellent sound absorption properties can be obtained.

[0045] In particular, in the resin fiber layer 20 formed from hot melt resin, by using fibers having a preferred fiber diameter while keeping the air permeability within this range, the distribution of voids and fibers becomes appropriate, resulting in very excellent sound absorption properties.

[0046] The air permeability of the resin fiber layer 20 was measured in accordance with the air permeability test of JIS L 1096.

[0047] In addition, when the resin fiber layer 20 is bonded to the substrate 30, the air permeability of the resin fiber layer 20 can be determined by forming an identical resin fiber layer (a resin fiber layer having the same components, structure, thickness, etc.) on a release film, removing the release film to produce a single-layer resin fiber layer, and measuring the air permeability of this resin fiber layer.

[0048] 1-1-3. Structure 1-1-3-1. Fiber Diameter The fiber diameter of the fibers constituting the resin fiber layer 20 can be, for example, 1 to 100 μm, 3 to 30 μm, or 5 to 20 μm. When the fiber diameter is within these ranges, excellent sound absorption properties are obtained. The fiber diameter is calculated as follows. First, the resin fiber layer 20 is photographed with an SEM, and the fiber diameters (widths of the minor axes) of 10 fibers included in the obtained image are measured, and the average of these is taken as the fiber diameter.

[0049] 1-1-3-2. Thickness Although details will be described later, the laminate 10 of this embodiment is formed by spraying a hot melt resin onto the substrate 30, thereby fusing the resin fiber layer 20 onto the substrate 30. Furthermore, the resin fiber layer 20 can be formed to have a substantially uniform thickness. This allows the laminate 10 to fully exhibit stable sound absorption properties.

[0050] The thickness of the resin fiber layer 20 can be, for example, 0.1 to 100 mm, 1 to 50 mm, 5 to 40 mm, or 10 to 30 mm. By setting the thickness of the resin fiber layer 20 in such a range, excellent sound absorption properties can be obtained while the layer is easy to manufacture.

[0051] The thickness reduction rate of the resin fiber layer 20 is preferably 40% or less, 30% or less, 20% or less, 10% or less, or 7% or less. When the thickness reduction rate of the resin fiber layer 20 is in this range, high sound absorption properties are likely to be exhibited for a long period of time.

[0052] Here, the thickness reduction rate of the resin fiber layer 20 is measured by the following method.

[0053] The thickness of the resin fiber layer 20 immediately after production (where the hot melt resin is sufficiently solidified) is defined as the initial thickness T Ａ The thickness of the resin fiber layer 20 after being kept under constant temperature and humidity conditions (25° C., 50% RH) for one week (168 hours) is referred to as the thickness after keeping T Ｂ The thickness reduction rate is [(T Ａ -T Ｂ ) / T Ａ ] is calculated as follows.

[0054] When the laminate 10 of this embodiment is used as a sound-absorbing material, the frequency band at which sound is easily absorbed changes depending on the thickness of the resin fiber layer 20. For example, increasing the thickness of the resin fiber layer 20 shifts the peak of the sound absorption frequency to the lower frequency side. Therefore, the thickness of the resin fiber layer 20 can be adjusted depending on the application of the resin fiber layer 20, the environment in which it is used, and the like.

[0055] On the other hand, in a conventional technology (Patent Document 1) in which a substrate and a resin fiber layer are integrally joined by spot welding using ultrasonic welding or the like, the resin fiber layer has a concave structure with a plurality of concave welds. The concave welds are recessed portions formed for spot welding the resin fiber layer to the substrate. The concave welds are portions whose thickness is half or less of the thickness of the resin fiber layer and whose width is 5 mm to 10 mm. Because the resin fiber layer is thinner at the concave welds than at other portions, it is unable to fully exhibit sound absorption properties.

[0056] In contrast, the laminate 10 of this embodiment is formed by spraying a hot melt resin onto the substrate 30, as described above, to fuse the resin fiber layer 20 onto the substrate 30. That is, the resin fiber layer 20 is fixed (fused) to the substrate 30 over almost the entire surface. This eliminates the need for spot welding as in the prior art, and the resin fiber layer 20 does not have a concave welded portion (concave structure). Therefore, the laminate 10 of this embodiment can fully exhibit stable sound absorption properties.

[0057] 1-1-3-3. Basis Weight The basis weight of the resin fiber layer 20 is, for example, 50 to 1,000 g / m ２ , 75-750g / m ２ , or 100 to 500 g / m ２ By setting the basis weight of the resin fiber layer 20 in this range, excellent sound absorption properties can be obtained.

[0058] The fiber diameter, basis weight, thickness, air permeability, etc. can be adjusted by the melt viscosity of the hot melt resin, the type of nozzle used when spraying the hot melt resin, and the spray application conditions (pressure, time, etc.).

[0059] The resin fiber layer 20 according to this embodiment has excellent sound absorbing properties and can therefore be preferably used as a sound absorbing material.

[0060] 1-2. Substrate 1-2-1. Shape The shape of the substrate 30 is not particularly limited, and any appropriate shape can be used. In particular, the resin fiber layer 20 according to this embodiment can be formed simply by spraying a hot melt resin onto the substrate 30. Therefore, even when the substrate 30 is a member having a complex shape, the resin fiber layer 20 can be easily manufactured on the substrate 30, and excellent sound absorption properties can be imparted.

[0061] For example, a member having a plurality of ribs (protrusions) may be used for the substrate 30. Fig. 2 is a cross-sectional view schematically showing a laminate when a member having ribs is used for the substrate. Fig. 2(a) shows a conventional laminate formed by welding, and Fig. 2(b) shows the laminate 10 of this embodiment.

[0062] In conventional laminates formed by welding, welding is usually performed so as to avoid the areas where ribs are present on the substrate (Fig. 2(a)), making it impossible to form a resin fiber layer over the ribs.

[0063] In contrast, in the laminate 10 of this embodiment, the resin fiber layer 20 is formed by spraying hot melt resin onto the substrate 30, so that the resin fiber layer 20 can be formed across the rib 31 (Figure 2(b))

[0064] The laminate 10 of this embodiment can be easily manufactured without being affected by the shape of the substrate 30 even when a plurality of ribs (protrusions) 31 are formed on the substrate 30 .

[0065] Furthermore, in the laminate 10 of this embodiment, the resin fiber layer 20 is formed across the ribs 31, and therefore the area (sound absorption area) of the resin fiber layer 20 is larger than that of a conventional laminate formed by welding, thereby enabling the laminate 10 to exhibit better sound absorption properties.

[0066] 1-2-2. Material The material of the base material 30 is preferably an olefin-based resin (polyolefin).

[0067] Examples of polyolefins include polyethylene, polypropylene, polybutene-1, ethylene-propylene copolymer, ethylene-α-olefin copolymer, and polymer blends thereof. One of these materials may be used alone, or a composite of two or more materials may be used.

[0068] As described above, in the laminate 10 of this embodiment, the resin fiber layer 20 is formed of an olefin-based hot melt resin. When the resin fiber layer 20 and the substrate 30 are formed of the same olefin-based material, the bonding strength between the resin fiber layer 20 and the substrate 30 can be increased.

[0069] In addition, in many conventional laminates, the substrate and the resin fiber layer are formed from different materials, which necessitates the process of separating the substrate and the resin fiber layer during recycling. In contrast, in the laminate 10 of this embodiment, the resin fiber layer 20 and the substrate 30 are made from the same olefin-based material. This eliminates the need to separate the resin fiber layer 20 and the substrate 30 during recycling, making the process easier.

[0070] 2. Manufacturing Method of Laminated Body Hereinafter, a manufacturing method of the laminated body will be described.

[0071] The laminate is obtained by spraying a molten hot-melt resin directly onto a substrate. The fibrous hot-melt resin is fused to the substrate when it comes into contact with the substrate in a molten and / or softened state, and then cooled and solidified to form a resin fiber layer.

[0072] As the spraying method, known methods such as curtain spray, omega spray, spiral spray, summit spray, etc. can be applied.

[0073] On the other hand, in conventional laminates in which the substrate and the resin fiber layer are integrally joined by spot welding using ultrasonic welding or the like, the welded portion reaches a high temperature of nearly 300° C. during welding, which places a large load on the substrate. In contrast, the laminate of this embodiment is obtained by spraying a hot melt resin onto the substrate, so the load on the substrate can be reduced compared to conventional laminates.

[0074] The hot melt resin used for spray coating can be produced by a known method, for example, by feeding the raw materials described above into a continuous mixer such as a single-screw or twin-screw extruder, or a batch mixer such as a roll mixer, a Banbury mixer, a kneader, a planetary mixer, or a high-shear Z-blade mixer, and mixing them at a predetermined temperature for a predetermined time.

[0075] For the purpose of increasing the bonding strength of the resin fiber layer to the substrate, the substrate may be subjected to a surface treatment (cleaning, smoothing, roughening, discharge treatment, UV treatment, etc.).

[0076] The laminate of this embodiment can be constructed simply by spraying the hot melt resin onto the substrate to form a resin fiber layer, and the hot melt resin itself adheres to the substrate (no steps are required for heat welding the nonwoven fabric or applying adhesive processing to the nonwoven fabric). Therefore, a resin fiber layer with excellent sound absorption properties derived from the hot melt resin can be easily formed, and the resin fiber layer is not easily peeled off because it is surface-bonded almost uniformly.

[0077] Conventional laminates, which are obtained by spot welding a pre-prepared resin fiber layer to a substrate, and the laminate of this embodiment, which is obtained by spray-coating a hot melt resin onto a substrate, have different bonding areas. That is, conventional laminates have limited number and area of ​​welded parts, and the resin fiber layer is bonded to the substrate only at the welded parts. In contrast, the laminate of this embodiment allows the resin fiber layer to be bonded to the substrate over almost the entire surface.

[0078] More specifically, in conventional laminates obtained by spot welding resin fiber layers, the adhesive area of ​​the resin fiber layers is usually less than 10%, and they tend to peel easily.

[0079] In contrast, in the laminate according to this embodiment, the ratio of the bonding area between the resin fiber layer and the substrate to the substrate is 10% or more, 30% or more, 50% or more, 60% or more, 70% or more, or 80% or more. The bonding area of ​​the resin fiber layer to the substrate can be, for example, 99% or less, 95% or less, or 90% or less. In the laminate according to this embodiment, the substrate and the resin fiber layer are sufficiently bonded while maintaining the fiber structure.

[0080] The adhesive area of ​​the resin fiber layer can be calculated by peeling off the fibers other than the adhesive portion from the substrate and analyzing the adhesive portion (the portion remaining after the fibers have been peeled off) under a microscope.

[0081] 3. Applications The laminate and sound-absorbing material of the present embodiment may be applied to any location where sound absorption is required, for example, interior and exterior components of buildings, airplanes, ships, vehicles (automobiles, railway cars), and other vehicles.

[0082] The laminate of the present invention will be described in detail below with reference to examples, but the present invention is not limited thereto. In the examples, the melt flow rate (MFR) is a value measured in accordance with JIS K7210-1:2014 (ISO1133-1:2011) Plastics - Determination of melt flow rate (MFR) and melt volume flow rate (MVR) of thermoplastics - Part 1: Standard test method.

[0083] <<Production of Laminate / Resin Fiber Layer>> The following olefin-based hot melt resins were used to form the resin fiber layer: PP_1 (manufactured by Tosho Chemical Co., Ltd., polypropylene, MFR 1500 g / 10 min) PP_2 (manufactured by Tosho Chemical Co., Ltd., polypropylene, MFR 1800 g / 10 min) PP (manufactured by Xiamen Keyuan Co., Ltd., polypropylene, MFR 1500 g / 10 min) PR100 (manufactured by TEX YEAR Co., Ltd., polypropylene): Brookfield viscosity 1200 cps (190°C)

[0084] A molten hot melt resin maintained at 180°C was sprayed onto a polypropylene (PP) substrate, and the hot melt resin was cooled and solidified at room temperature to obtain laminates comprising a substrate and a resin fiber layer according to Examples 1 to 4. An Auto Supply (manufactured by ITW) with a 6-hole Omega nozzle was used for spray coating in Examples 1 and 3. An Auto Supply (manufactured by ITW) with an AE3 nozzle was used for spray coating in Examples 2 and 4.

[0085] The components of the resin fiber layer (hot melt resin), thickness of the resin fiber layer, basis weight, fiber diameter, air permeability, storage modulus G', loss modulus G'', loss tangent tan δ, glass transition temperature, and tack-free time for each example are shown in each table. The tack-free time is the time it takes for the resin fiber to no longer adhere to a finger after spray application of the hot melt resin. Photographs (SEM photographs) of the fibers of the resin fiber layer for each example taken with a scanning electron microscope (SEM) (Keyence Corporation, VHX-D510) are also shown in the tables.

[0086] The thickness, basis weight, fiber diameter and air permeability of the resin fiber layer were adjusted by changing the spray application conditions (application time) and nozzle diameter.

[0087] The thickness of the resin fiber layer is determined by the above-mentioned method using the initial thickness T Ａ and the thickness after holding T Ｂ The thickness reduction rate was calculated together with the measured values.

[0088] In Comparative Example 1, a laminate according to Comparative Example 1 was obtained by the same manufacturing method as in Example 1, except that DH-672 (polyamide, manufactured by Nogawa Chemical Co., Ltd.) was used as the resin constituting the resin fiber layer.

[0089] In Comparative Example 2, the same manufacturing method as in Example 1 was used, except that SA08A (manufactured by Japan Polypropylene Co., Ltd., polypropylene) with an MFR of 75 g / 10 min was used as the resin constituting the resin fiber layer. In Comparative Example 2, the melt viscosity of the resin was higher than in Examples 1 to 4, making it difficult to form the resin fiber layer when spray-coating the hot-melt resin onto the substrate. As a result, no laminate was obtained, and product evaluation was not possible.

[0090] <<Evaluation>> For each of the laminates of Examples 1 to 4 and Comparative Examples 1 and 2, the adhesion between the substrate (polypropylene) and the resin fiber layer and the sound absorption coefficient were evaluated.

[0091] <Adhesion between substrate and resin fiber layer (adhesion with PP)> The fibers (hot melt resin) other than the adhesive portion were peeled off from the substrate, and the area of ​​the adhesive portion (the portion remaining after the fibers were peeled off) was calculated using a microscope and evaluated as follows: A: Adhesion area is 80% or more B: Adhesion area is 50% or more but less than 80% C: Adhesion area is 10% or more but less than 50% D: Adhesion area is less than 10%

[0092] <Sound absorption coefficient> The sound absorption coefficient was measured in accordance with JIS A 1405-2, with a sample size of 28.9φ, incident surface as fiber surface, target frequency of 4000 Hz, and n=2, and was evaluated as follows: A: 0.6 or more and 1.0 or less B: 0.5 or more and less than 0.6 C: 0.1 or more and less than 0.5

[0093]

[0094] From the above results, it can be seen that the laminates including the resin fiber layer according to each example have sufficient sound absorption properties. Furthermore, since the resin fiber layer is obtained by simply spraying the molten hot melt resin onto the target object, it is easy to work with and has good adhesion to the substrate.

[0095] The laminate and sound-absorbing material of the present invention are easily recyclable and have sufficient sound-absorbing properties, and therefore can be used, for example, for interior and exterior components in buildings, airplanes, ships, vehicles (automobiles, railway cars), and other vehicles. CROSS-REFERENCE TO RELATED APPLICATIONS

[0096] This application claims priority based on Japanese Patent Application No. 2023-103689, filed with the Japan Patent Office on June 23, 2023, the entire disclosure of which is incorporated herein by reference in its entirety.

[0097] 10 Laminate 20 Resin fiber layer 30 Base material 31 Rib (protrusion)

Claims

1. comprising a resin fiber layer formed of hot melt resin and a base material, The aforementioned hot melt resin is an olefin-based hot melt resin. The material of the aforementioned substrate is an olefin resin. The following conditions (A) and / or (B) must be met: (A) The resin fiber layer is formed by spray-coating the hot melt resin onto the substrate. (B) The ratio of the adhesive area between the resin fiber layer and the substrate to the area of ​​the substrate is 10% or more. Furthermore, a laminate that satisfies one or more of the following conditions (C)-(J). (C) The basis weight of the resin fiber layer is 410 g / m² or more. (D) The crystallization temperature of the hot melt resin is 50°C or higher. (E) The thickness of the resin fiber layer is 15 mm or more. (F) The base material is a member having a protrusion. (G) The resin fiber layer has a thickness reduction rate of 40% or less as measured by the following measurement method. (Measurement method) After manufacturing, the thickness of the resin fiber layer when the hot melt resin has fully solidified is defined as the initial thickness TA. The thickness of the resin fiber layer 20 after being held under constant temperature and humidity conditions (25°C, 50% RH) for one week (168 hours) is defined as the post-holding thickness TB. The thickness reduction rate is calculated as [(TA - TB) / TA]. (H) The air permeability of the resin fiber layer is 136 cm³ / cm² / s or more. (I) The ratio of the adhesive area between the resin fiber layer and the substrate to the area of ​​the substrate is 80% or more. (J) Excluding those in which the base material is nonwoven fabric and polyurethane foam.

2. A sound-absorbing material comprising the laminate described in Claim 1.

3. An automotive interior member comprising the laminate described in Claim 1.