Vehicular interior finishing material and seat back panel

Abstract

This vehicular interior finishing material has a layered structure including n layers (where n is a natural number equal to or greater than 2), and at least includes a substrate that is a first layer and a skin layer that is an nth layer. The vehicular interior finishing material is configured such that formula (1) is satisfied, where dn (mm) is the thickness of each of the n layers, En (GPa) is the Young's modulus, and ρ (g / cm3) is the density of the entire vehicular interior finishing material. In addition, this seat back panel is formed using the vehicular interior finishing material.

Description

Vehicle interior materials and seat back panels

[0001] The present application relates to a vehicle interior material and a seat back panel using the same.

[0002] Conventionally, a vehicle seat back panel formed by injection molding of PP (polypropylene) has been known. Patent Document 1, for example, describes a press-molded body that can be used as a vehicle seat back. The press-molded body in Patent Document 1 has a surface layer fixed to a nonwoven fabric via an adhesive layer, and Patent Document 1 describes the use of natural leather, synthetic leather, fabric, or the like as the surface layer.

[0003] Japanese Patent Publication No. 2020-121551

[0004] To create a dignified vehicle interior space, vehicle interior materials used for seat back panels, etc., must have high rigidity sufficient to ensure a luxurious appearance. Furthermore, even if the vehicle interior material generates impact sounds, it is desirable that the impact sounds generated by the vehicle interior material be low-pitched and elegant. However, generally, increasing the rigidity of a material results in high-pitched impact sounds that lack a luxurious feel. Therefore, it is desirable to develop a vehicle interior material that can achieve a luxurious feel in both rigidity and impact sounds. In this regard, the press-molded product described in Patent Document 1 aims to ensure ease of sewing and strength, but does not take into consideration the impact sounds generated by the press-molded product.

[0005] The present application aims to solve the above-mentioned problems by providing an improved interior material for a vehicle that satisfies the luxurious feel of both the appearance and the striking sound, and a seat back panel formed using the same.

[0006] In order to solve the above problems, in one embodiment of the present application, a vehicle interior material has a laminated structure of n layers (n is a natural number of 2 or more), and includes at least a base material as a first layer and a skin layer as an nth layer. This vehicle interior material is configured to satisfy the following formula (1), where dn (mm) is the thickness of each of the n layers, En (GPa) is the Young's modulus, and ρ (g / cm3) is the density of the entire vehicle interior material.

[0007]

[0008] Further, a seat back panel according to another embodiment of the present application is formed using any of the vehicle interior materials according to the present application.

[0009] The vehicle interior material according to the present application ensures the necessary rigidity to give the vehicle a luxurious appearance, and even if a hitting sound is generated, the hitting sound can be made to be elegant. Furthermore, by using a seat back panel formed using this vehicle interior material in a vehicle seat, the interior space of the vehicle can be made to have a luxurious feel.

[0010] FIG. 1 is a diagram showing an example of a seat arranged inside a vehicle. FIG. 2 is a diagram showing a cross-sectional configuration of a vehicle interior material according to a first embodiment of the present application. FIG. 3 is a diagram explaining an outline of the relationship satisfied by the base material and the surface skin layer of the vehicle interior material according to the first embodiment of the present application. FIG. 4 is a diagram showing measurement values ​​of a plurality of specific samples of the vehicle interior material and experimental results of shape retention force and sound volume. FIG. 5 is a diagram showing the relationship between the frequency and sound pressure level of hammering sounds emitted from samples A and B of the vehicle interior material. FIG. 6 is a diagram showing a cross-sectional configuration of a vehicle interior material according to a second embodiment of the present application.

[0011] Hereinafter, an embodiment of the vehicle interior material according to the present application will be described with reference to the drawings. In each drawing, the same or corresponding parts are designated by the same reference numerals, and the description thereof will be simplified or omitted.

[0012] Embodiment 1. Fig. 1 is a diagram showing an example of a seat arranged in a vehicle. A vehicle interior material 10 according to this embodiment is used, for example, as shown in Fig. 1, as a material for the seat back panel 2 of the vehicle seat 1. The seat back panel 2 is located in a conspicuous location, particularly in front of the rear seat occupants, occupies a large area in the vehicle cabin, and is prone to being hit by people's hands and feet, generating impact sounds. Therefore, by applying the vehicle interior material 10 according to this embodiment to the seat back panel 2, the appearance of the vehicle cabin space can be effectively made luxurious and the generation of unrefined impact sounds can be effectively suppressed.

[0013] However, the vehicle interior material 10 can also be suitably used for other parts installed inside a vehicle, particularly parts that are likely to be touched by people or that are easily visible to people. Specifically, the vehicle interior material 10 can be used as a material that constitutes the whole or part of, for example, a dashboard, an instrument panel, a door trim, a pillar trim, a rear parcel shelf, and the like, in addition to a seat back panel.

[0014] 2 is a diagram showing a cross-sectional configuration of a vehicle interior material according to the present embodiment. As shown in FIG. 2, the vehicle interior material 10 has a laminated structure in which a base material 11 and a surface layer 12 are bonded together.

[0015] The substrate 11 is made of a relatively light material whose composition is adjusted to ensure the necessary rigidity, and the substrate 11 ensures sufficient strength for the vehicle interior part. The substrate 11 is also formed using a material that is lighter (has a lower density) than at least the skin layer 12. Specific examples of the material for the substrate 11 include fibers, felt such as compressed felt or knitted felt, and hollow resin structures (e.g., honeycomb structures) and foamed resins such as urethane foam. The substrate 11 may also be configured by laminating these felts and resins.

[0016] The surface layer 12 is made of, for example, synthetic leather containing PVC (polyvinyl chloride). Synthetic leather containing PVC includes synthetic leather made only of PVC and synthetic leather primarily composed of PVC. Examples of synthetic leather primarily composed of PVC include PVC coated with a resin such as nylon or polyurethane. The surface layer 12 may also be made of synthetic leather containing other materials, such as PP (polypropylene), fibers such as nonwoven fabrics and woven fabrics, or natural leather. The use of these materials can impart a luxurious appearance to the vehicle interior material 10.

[0017] 3 is a diagram illustrating an outline of the relationship satisfied by the substrate 11 and the skin layer 12 of the vehicle interior material 10 according to the first embodiment. In FIG. 3, the horizontal axis represents the value of α shown in formula (2). In formula (2), d1 (mm) represents the thickness of the substrate 11, d2 (mm) represents the thickness of the skin layer 12, E1 (GPa) represents the Young's modulus of the substrate 11 at room temperature (5°C to 35°C), and E2 (GPa) represents the Young's modulus of the skin layer 12 at room temperature (5°C to 35°C).

[0018]

[0019] On the other hand, the vertical axis represents the value of β shown in the following formula (3): In formula (3), ρ (g / cm ３ ) indicates the average density of the entire vehicle interior material 10.

[0020]

[0021] The vehicle interior material of this embodiment is configured to belong to region C between solid lines A and B. Specifically, α in the above formula (2) is a value that correlates with the rigidity of the material. That is, the smaller the value of α, the lower the rigidity, and if the value of α is excessively small, it becomes difficult to maintain the shape and the interior material will lack a luxurious feel. In this embodiment, from the perspective of ensuring the rigidity necessary to create a luxurious appearance, the minimum value of α, i.e., the range of solid line B in Figure 3, is specified, as will be described later, and the α of the vehicle interior material 10 is set to be in a range greater than solid line B.

[0022] Generally, the higher the rigidity, the higher the pitch of the hitting sound from the material, and the higher the mass, the lower the pitch of the hitting sound. From this viewpoint, the inventor of the present application considered that the ratio of mass to rigidity has a certain correlation with the pitch of the hitting sound from the material, that is, the frequency, and as a result of research, found that the ratio β / α can be a parameter that indicates the pitch of the hitting sound.

[0023] Specifically, when the value of the ratio β / α is small, the hammering sounds emitted from that material will be high-frequency and lack quality. Therefore, in this embodiment, the value of the ratio β / α within the range acceptable for hammering sounds, i.e., the slope of the solid line A in Figure 3, is specified, and the value of the ratio β / α of the vehicle interior material 10 is set to be larger than the slope of the solid line A.

[0024] Fig. 4 shows the results of experiments confirming the values ​​of α and β, shape retention, and sound volume of several specific samples of vehicle interior materials. The rightmost column in Fig. 4, "Sound," shows the sound pressure level 1 m directly above the material when it was vibrated at 10 (N).

[0025] Sample A in Figure 4 is a conventional interior material injection-molded from PP. As shown in Figure 4, the α value of conventional vehicle interior materials is 3104. In the case of Sample A made of PP, the α value was also sufficiently large, and shape retention was sufficient. However, β was 2700, and the ratio β / α was relatively small at approximately 0.87, and it was confirmed that a high-pitched hammering sound was generated.

[0026] For sample B, α was 94.7 and β was 1522. Although the α value for sample B was smaller than that of sample A made of PP, it was judged to be within the acceptable range from the viewpoint of shape retention. On the other hand, the ratio β / α was approximately 16.07, and the hitting sound was judged to be low-pitched and of high quality.

[0027] Fig. 5 shows the sound pressure level for each frequency component of the hammering sounds generated when Sample A and Sample B are vibrated at a constant intensity. It can be seen from Fig. 5 that Sample B has a sufficiently low sound pressure level on the high frequency side compared to Sample A made of conventional PP. This also confirms that Sample B is a good vehicle interior material that generates low-pitched hammering sounds.

[0028] Sample C had an α of 2990 and a β of 3133. The α value was larger as it approached that of sample A made of PP, and the shape retention was sufficient. On the other hand, the ratio β / α was about 1.05, and the hitting sound was determined to be lower than that of PP and within the acceptable range.

[0029] Samples D and E are both examples of fabric-covered seat back panels. The ratios β / α of Samples D and E were sufficiently small, at approximately 33.61 and 2.40, respectively, and the impact sounds were actually low. However, the ratios α were small, at 9.7 and 87, respectively, and the shape retention was determined to be below the acceptable range.

[0030] Experiments using the above samples were repeated, and from the viewpoint of rigidity, the range of α for the vehicle interior material 10 of this embodiment was specified as being greater than 94. Furthermore, from the viewpoint of hammering sound, the range of the ratio β / α for the vehicle interior material 10 of this embodiment was specified as being greater than 1, that is, α being smaller than β. In other words, the vehicle interior material 10 of this embodiment is configured to satisfy the relationship of the following formula (3).

[0031]

[0032] The above formulas (2) and (4) are defined using Young's modulus at room temperatures between 5°C and 35°C. This means that the relationship in formula (4) is satisfied regardless of the Young's modulus used for calculation within the room temperature range between 5°C and 35°C. However, if the vehicle interior material 10 satisfies the relationship in formula (4) within the room temperature range, it can achieve a certain level of luxury in both rigidity and impact sound even outside the room temperature range, for example, even in a high-temperature environment such as the maximum temperature of 80°C in the thermal cycle test. Furthermore, if the substrate 11 or the skin layer 12 is a hollow structure, the Young's modulus may be anisotropic. In such a case, the Young's modulus in one of the different directions is used.

[0033] As described above, the vehicle interior material 10 of this embodiment has a good appearance and produces hammering sounds that do not impair a luxurious feel, because the substrate 11 and the skin layer 12 satisfy the relationships specified by the thicknesses d1 and d2, the Young's moduli E1 and E2, and the density ρ. Therefore, by using the vehicle interior material 10 as an interior part of a vehicle, the exterior of the vehicle interior can be made luxurious, and even if hammering sounds are produced, they can be made low-pitched and refined, creating a luxurious feel in the vehicle interior as a whole.

[0034] Embodiment 2. Figure 6 is a diagram schematically illustrating the cross-sectional configuration of a vehicle interior material according to Embodiment 2. In Embodiment 1, the vehicle interior material 10 is described as being composed of two layers: a substrate 11 and a skin layer 12. In contrast, as shown in Figure 6, the vehicle interior material 20 according to Embodiment 2 has n-2 intermediate layers between the substrate 11 and the skin layer 12. That is, the vehicle interior material 20 has a laminated structure of n layers in total. Here, n is a natural number equal to or greater than 3. For convenience, the substrate 11 will be described as the first layer, the intermediate layers will be referred to as the second layer, the third layer, ..., and (n-1)th layer, in that order from the substrate 11 side, and the skin layer 12 will be described as the nth layer.

[0035] The intermediate layer 13 is disposed to bond the substrate 11 and the skin layer 12 and to reinforce the vehicle interior material 10. For example, a resin sheet, a nonwoven fabric, a fiber, PP, or the like is used as the intermediate layer 13. There is no limitation on the number of layers of the intermediate layer 13.

[0036] The vehicle interior material 20 is configured to satisfy the relationship of the following formula (5), similar to the above formula (4). However, in formula (5), the thickness of each layer from the substrate 11, which is the first layer, to the n-th layer, which is the skin layer 12, is dn (mm), the Young's modulus at room temperature (5 to 35°C) is En (Gpa), and the average density of the entire material is ρ (g / cm ３ ) is represented as

[0037]

[0038] Even when the vehicle interior material 20 has a laminated structure of three or more layers, by configuring it so that the relationship of the above formula (5) is satisfied, it is possible to achieve both a luxurious appearance and a refined hitting sound for the vehicle interior material 20. Therefore, by using the vehicle interior material 20 for vehicle interior parts, the exterior of the vehicle cabin is given a luxurious feel, and even if a hitting sound is generated, it can be made into a low-pitched, refined sound, thereby creating a luxurious feeling in the vehicle cabin as a whole.

[0039] In addition, in the above formula (5), the Young's modulus at room temperature of 5° C. to 35° C. is used, and the relationship in the above formula (4) is satisfied regardless of the Young's modulus at any temperature within the room temperature range of 5° C. to 35° C. Furthermore, if a hollow structure or the like is used in any layer and its Young's modulus is anisotropic, the Young's modulus in one of the different directions is used.

[0040] In the above embodiments, when the number, quantity, amount, range, etc. of each element is mentioned, the present invention is not limited to the mentioned numbers unless otherwise specified or clearly specified in principle. Furthermore, the structures, etc. described in the embodiments are not necessarily essential to the present invention unless otherwise specified or clearly specified in principle.

[0041] REFERENCE SIGNS LIST 1 seat 2 seat back panel 10, 20 vehicle interior material 11 substrate 12 skin layer 13 intermediate layer

Claims

1. A vehicle interior material having a laminated structure of n layers (n is a natural number of 2 or more), At least a first layer, which is a substrate, and an nth layer, which is a skin layer, The thickness of each of the n layers is dn (mm), the Young's modulus is En (MPa), and the density of the entire vehicle interior material is ρ (g / cm ３ ) and The following formula (1) [0010] A vehicle interior material characterized in that it is configured to satisfy the relationship:

2. 2. The vehicle interior material according to claim 1, wherein the base material is made of a fiber, a felt, a resin foam, or a hollow resin structure.

3. 3. The vehicle interior material according to claim 1, wherein the surface layer is made of synthetic leather, nonwoven fabric, woven fabric, or natural leather.

4. The n is a natural number of 3 or more, and the vehicle interior material includes n-2 intermediate layers disposed between the surface layer and the base material, 4. The vehicle interior material according to claim 1, wherein the intermediate layer includes a layer made of any one of a resin sheet, a fiber, a nonwoven fabric, and polypropylene.

5. A seat back panel formed by using the vehicle interior material according to any one of claims 1 to 4.

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