Vehicle interior materials and seat back panels

Abstract

The vehicle interior material of this application has a layered structure of n layers (n is a natural number of 2 or more), including at least a substrate as the first layer and a skin layer as the nth layer. The vehicle interior material is configured such that, given the thickness of each of the n layers is dn (mm), the Young's modulus is En (GPa), and the overall density of the vehicle interior material is ρ (g / cm3), it satisfies the following equation (1). Furthermore, the seat back panel of this application is formed using this vehicle interior material.

Description

Technical Field

[0001] This application relates to interior materials for vehicles and seat back panels using such interior materials. Background Technology

[0002] Conventionally, seat backrests for vehicles have been known to be formed by injection molding of PP (polypropylene). Additionally, for example, Patent Document 1 describes a stamped body suitable for use as a vehicle seat backrest. The stamped body in Patent Document 1 is formed by bonding a surface layer to a non-woven fabric; Patent Document 1 describes using natural leather, synthetic leather, or fabric as the surface layer.

[0003] Existing technical documents

[0004] Patent documents

[0005] Patent Document 1: Japanese Patent Application Publication No. 2020-121551 Summary of the Invention

[0006] The problem that the invention aims to solve

[0007] To create a sophisticated car interior space, vehicle interior materials used for materials such as seat back panels need to possess high rigidity to ensure a premium appearance, and it is desirable to produce a low-pitched, sophisticated impact sound even when impact sounds are generated from the vehicle interior materials. However, generally speaking, increasing the rigidity of the material results in a high-pitched impact sound that lacks a premium feel. Therefore, it is desirable to develop vehicle interior materials that can achieve a premium feel by balancing both rigidity and impact sound. In this regard, the stamped body described in Patent Document 1 aims to ensure ease of sewing and strength, without considering the impact sound from the stamped body.

[0008] This application aims to solve the aforementioned problems by providing an improved vehicle interior material that satisfies both aesthetic and impact sound requirements, and a seat back panel formed using the vehicle interior material.

[0009] Methods for solving problems

[0010] To address the aforementioned issues, in one embodiment of this application, the vehicle interior material has an n-layered structure, where n is a natural number greater than or equal to 2, and includes at least a substrate as the first layer and a skin layer as the nth layer. This vehicle interior material is configured such that, given the thickness of each of the n layers is dn (mm), the Young's modulus is En (GPa), and the overall density of the vehicle interior material is ρ (g / cm³), it satisfies the following equation (1).

[0011] [Number 1]

[0012]

[0013] In addition, the other types of seat back panels in this application are formed by using any of the vehicle interior materials of this application.

[0014] Invention Effects

[0015] The vehicle interior material according to this application achieves a premium appearance by ensuring necessary rigidity, and produces a refined impact sound even when a collision occurs. Furthermore, by using seat back panels made from this vehicle interior material for vehicle seats, the interior space of the vehicle can be made to feel premium. Attached Figure Description

[0016] Figure 1 This is a diagram showing an example of a seat configured inside a vehicle.

[0017] Figure 2 This is a schematic diagram illustrating the cross-sectional structure of the vehicle interior material according to Embodiment 1 of this application.

[0018] Figure 3 This is a diagram illustrating the relationship between the substrate and the outer layer of the vehicle interior material according to Embodiment 1 of this application.

[0019] Figure 4 The graph shows the experimental results of measurements, shape retention, and sound levels for several specific samples of interior materials used in vehicles.

[0020] Figure 5 This is a graph showing the relationship between the frequency and sound pressure level of the impact sound emitted from samples A and B of vehicle interior materials.

[0021] Figure 6 This is a schematic diagram illustrating the cross-sectional structure of the vehicle interior material according to Embodiment 2 of this application. Detailed Implementation

[0022] Hereinafter, embodiments of the vehicle interior material of this application will be described with reference to the accompanying drawings. Furthermore, in the drawings, the same or equivalent parts are labeled with the same reference numerals, and their descriptions are simplified or omitted.

[0023] Implementation method 1.

[0024] Figure 1 This is a diagram illustrating an example of a seat configured within a vehicle. For example, as shown... Figure 1As shown, the vehicle interior material 10 of this embodiment is used as the material for the seat back panel 2 of the vehicle seat 1. The seat back panel 2 is located in a prominent position in front of a person sitting in the rear seat, occupies a large area in the passenger compartment, and is easily touched by people's hands and feet, which can easily produce collision noise. Therefore, by applying the vehicle interior material 10 of this embodiment to the seat back panel 2, it is possible to effectively make the appearance of the passenger compartment space feel more upscale and to effectively suppress the generation of unpleasant collision noise.

[0025] However, the vehicle interior material 10 can be appropriately used in other components installed inside the vehicle, especially in areas that are in contact with human hands or easily visible to the human eye. Specifically, in addition to seat back panels, the vehicle interior material 10 can also be used as a material for the entirety or part of the control panel, dashboard, door trim, pillar trim, and rear parcel shelf, etc.

[0026] Figure 2 This is a schematic diagram illustrating the cross-sectional structure of the vehicle interior material according to this embodiment. (See diagram for example.) Figure 2 As shown, the interior material 10 for vehicles is a laminated structure formed by bonding a base material 11 with a surface layer 12.

[0027] As the base material 11, a relatively lightweight material is used, adjusted in a way that ensures the necessary rigidity, thereby ensuring sufficient strength for the interior components used in the vehicle. Furthermore, the base material 11 is formed using a material that is at least lighter (lower density) than the outer layer 12. Specifically, the material used as the base material 11 may be, for example, felt such as fiber, compressed felt, or woven felt, or foamed resin such as polyurethane foam, and hollow resin structures (e.g., honeycomb structures). Alternatively, the base material 11 may also be a structure formed by laminating these felts and resins.

[0028] The outer skin layer 12 is, for example, made of synthetic leather containing PVC (polyvinyl chloride). Here, synthetic leather containing PVC includes synthetic leather made solely of PVC, and synthetic leather with PVC as the main component. Among synthetic leathers with PVC as the main component, there are examples of synthetic leather with nylon, polyurethane, or other resins coated on the surface of the PVC. Alternatively, the outer skin layer 12 may also be made of, for example, synthetic leather containing other materials such as PP (polypropylene), non-woven fabrics and other textile fibers, and natural leather. By using these materials, the appearance of the vehicle interior material 10 can be made to have a premium feel.

[0029] Figure 3 This is a schematic diagram illustrating the relationship between the base material 11 and the outer layer 12 of the vehicle interior material 10 according to Embodiment 1. Figure 3In equation (2), the horizontal axis represents the value of α shown in equation (2). In equation (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℃~35℃), and E2 (GPa) represents the Young's modulus of the skin layer 12 at room temperature (5℃~35℃).

[0030] [Number 2]

[0031]

[0032] On the other hand, the vertical axis represents the value of β as shown in equation (3). In equation (3), ρ (g / cm 3 ) indicates the overall average density of the interior materials used in the vehicle.

[0033] [Number 3]

[0034] β=1000(d1+d2)ρ·····(3)

[0035] The vehicle interior material in this embodiment is configured to occupy region C, which is enclosed by solid lines A and B. Specifically, α in the above formula (2) is a value related to the rigidity of the material. That is, the smaller the value of α, the lower the rigidity. If the value of α is too small, it is difficult to maintain its shape, and the interior material lacks a sense of luxury. In this embodiment, from the viewpoint of ensuring the rigidity required to create a sense of luxury in the appearance, as described later, a minimum value of α is determined, namely... Figure 3 The range of the solid line B in the text makes the α of the vehicle interior material 10 a larger range than the solid line B.

[0036] Furthermore, generally speaking, if the rigidity increases, the impact sound from the material becomes high-pitched; conversely, if the mass increases, the impact sound becomes low-pitched. Based on this viewpoint, the inventors of this application believe that the ratio of mass to rigidity is correlated with the pitch, i.e., frequency, of the impact sound from the material. The research results show that the ratio β / α can be used as a parameter to represent the pitch of the impact sound.

[0037] Specifically, when the value of the ratio β / α is small, the impact sound emitted from the material becomes a high-frequency, unpleasant sound. Therefore, in this embodiment, the value of the ratio β / α, which is within the acceptable range for impact sound, is determined. Figure 3 The slope of the solid line A in the figure makes the ratio β / α of the vehicle interior material 10 greater than the slope of the solid line A.

[0038] Figure 4 This is a graph showing the experimental results confirming the values ​​of α and β, as well as the shape retention force and sound intensity, for several specific samples of vehicle interior materials. Figure 4In the rightmost column, under the "Sound" section, the sound pressure level 1m directly above the material when it is vibrated at 10 N is shown.

[0039] Figure 4 Sample A is a conventional interior material injection molded from PP. For example... Figure 4 As shown, the value of α for conventional vehicle interior materials is 3104. In the case of sample A, which is made of PP, the value of α is also sufficiently large, and the shape retention is sufficient. However, β is 2700, and the ratio β / α is about 0.87, which is relatively small, and a high-pitched impact sound is confirmed.

[0040] Sample B has an α value of 94.7 and a β value of 1522. Compared to sample A, which is made of PP, sample B has a smaller α value, but from the viewpoint of shape retention, it is judged to be within the acceptable range. On the other hand, the ratio β / α is approximately 16.07, and the impact sound is judged to be low-pitched and tasteful.

[0041] Figure 5 This shows the sound pressure level of each frequency component of the impact sound produced when samples A and B are vibrated at a certain intensity. From Figure 5 It can be seen that, compared to the previous sample A made of PP, the sound pressure level on the high-frequency side of sample B is sufficiently low. This also confirms that sample B is a good interior material for vehicles that produces a low-pitched, impact sound.

[0042] For sample C, α is 2990 and β is 3133. The closer the value of α is to that of sample A, which is composed of PP, the larger it is, indicating sufficient shape retention. On the other hand, the ratio β / α is approximately 1.05, which is considered to be within the permissible low-frequency range of the impact sound, lower than that of PP.

[0043] Samples D and E are examples of padded seat back panels. The ratios β / α of samples D and E are sufficiently small, approximately 33.61 and 2.40 respectively, resulting in low-pitched impact sounds. However, α is as small as 9.7 and 87 respectively, indicating that the shape retention force is below the permissible range.

[0044] Experiments were repeatedly conducted using the samples described above. From a rigidity perspective, the range of α for the vehicle interior material 10 of this embodiment was determined to be greater than 94. Furthermore, from a collision sound perspective, the range of the ratio β / α for the vehicle interior material 10 of this embodiment was determined to be greater than 1, i.e., α is less than β. In other words, the vehicle interior material 10 of this embodiment is configured in a manner that satisfies the relationship of the following equation (4).

[0045] [Number 4]

[0046]

[0047] Furthermore, in the above equations (2) and (4), Young's modulus at a normal temperature of 5°C to 35°C is used for specification. This means that as long as the temperature is within the range of 5°C to 35°C, the relationship of equation (4) will be satisfied regardless of which temperature's Young's modulus is used for calculation. However, if the vehicle interior material 10 satisfies the relationship of equation (4) within the range of normal temperature, then even outside the range of normal temperature, in high-temperature environments such as the maximum temperature of 80°C in thermal cycling tests, it can still satisfy the high-end feel of both rigidity and impact sound to a certain extent. In addition, when the substrate 11 or the skin layer 12 is a hollow structure, Young's modulus sometimes exhibits anisotropy. In this case, Young's modulus in any different arbitrary direction is used.

[0048] As explained above, the vehicle interior material 10 of this embodiment achieves a pleasant appearance and produces a collision sound that does not compromise the sense of luxury by satisfying the relationship between the base material 11 and the outer layer 12 as determined by the aforementioned thicknesses d1 and d2, Young's modulus E1 and E2, and density ρ. Therefore, by using the vehicle interior material 10 in the interior parts of a vehicle, it is possible to give the interior of the cabin a sense of luxury, and even when collision sounds are produced, it is possible to produce a low-pitched and tasteful sound, thus creating an overall sense of luxury in the cabin.

[0049] Implementation method 2.

[0050] Figure 6 This is a schematic diagram showing the cross-sectional structure of the vehicle interior material according to Embodiment 2. In Embodiment 1, the vehicle interior material 10 was described as consisting of two layers: a base material 11 and a surface layer 12. In contrast, as... Figure 6 As shown, the vehicle interior material 20 of Embodiment 2 has an intermediate layer of n-2 layers between the substrate 11 and the outer skin layer 12. That is, the vehicle interior material 20 as a whole is a laminated structure of n layers. Here, n is a natural number of 3 or more. For convenience, the substrate 11 is referred to as the first layer, the intermediate layers are referred to as the second layer, the third layer... the (n-1)th layer from the substrate 11 side, and the outer skin layer 12 is referred to as the nth layer.

[0051] The intermediate layer 13 is configured for bonding the substrate 11 to the outer skin layer 12 and for reinforcing the vehicle interior material 10. For example, resin sheets, non-woven fabrics, fibers, and PP can be used as the intermediate layer 13. The number of layers in the intermediate layer 13 is not limited.

[0052] The vehicle interior material 20 is configured in the same way as in equation (4) above to satisfy the relationship in equation (5). In equation (5), dn (mm) represents the thickness of each layer from the substrate 11 (first layer) to the nth layer (outer layer) 12, En (GPa) represents the Young's modulus at room temperature (5–35°C), and ρ (g / cm³) represents the thickness of the outermost layer. 3 ) represents the average density of the whole.

[0053] [Number 5]

[0054]

[0055] When the vehicle interior material 20 has a layered structure of three or more layers, by constructing it in a manner that satisfies the relationship of the above formula (5), it is also possible to simultaneously achieve a high-end appearance and a tasteful collision sound for the vehicle interior material 20. Therefore, by using the vehicle interior material 20 for the interior parts of the vehicle, it is possible to give the interior of the car a high-end appearance, and even when a collision sound is generated, it can produce a low-pitched and tasteful sound, thus creating an overall high-end car interior.

[0056] Furthermore, in the above equation (5), the Young's modulus at room temperature of 5℃ to 35℃ is also used. As long as it is within the room temperature range of 5℃ to 35℃, the relationship of the above equation (4) will be satisfied regardless of which temperature of Young's modulus is used for calculation. In addition, when hollow structures are used in arbitrary layers, and their Young's modulus is anisotropic, the Young's modulus in different arbitrary directions is used.

[0057] Furthermore, when the number, quantity, quantity, range, etc., of each element are mentioned in the above embodiments, the present invention is not limited to the mentioned numbers, unless specifically stated or explicitly determined in principle. Additionally, the structures, etc., described in these embodiments are not necessarily essential to the present invention, except when specifically stated or explicitly determined in principle.

[0058] Explanation of reference numerals in the attached figures

[0059] 1 Seat

[0060] 2. Seat backrest

[0061] Interior materials for vehicles 10 and 20

[0062] 11 Substrate

[0063] 12 Epidermis

[0064] 13 Intermediate Layer

Claims

1. A vehicle interior material having an n-layered stacked structure, wherein, When n is a natural number greater than 2, it is characterized by: It includes at least a substrate as the first layer and an epidermis as the nth layer. Let the thickness of each of the n layers be dn (mm), the Young's modulus be En (GPa), and the overall density of the vehicle interior material be ρ (g / cm³). 3 When ), the following equation (1) is satisfied.

2. The vehicle interior material according to claim 1, characterized in that, The substrate is composed of fibers, felt, foamed resin, or a hollow structure of resin.

3. The vehicle interior material according to claim 1 or 2, characterized in that, The outer layer is made of synthetic leather, non-woven fabric, textiles, or natural leather.

4. The vehicle interior material according to claim 1 or 2, characterized in that, When n is a natural number greater than or equal to 3, and the vehicle interior material includes an intermediate layer of n-2 layers disposed between the outer skin layer and the substrate, the intermediate layer comprises a layer composed of any material selected from resin sheets, fibers, nonwoven fabrics, and polypropylene.

5. The vehicle interior material according to claim 3, characterized in that, When n is a natural number greater than or equal to 3, and the vehicle interior material includes an intermediate layer of n-2 layers disposed between the outer skin layer and the substrate, the intermediate layer comprises a layer composed of any material selected from resin sheets, fibers, nonwoven fabrics, and polypropylene.

6. A seat back panel formed using the vehicle interior material as described in any one of claims 1 to 5.

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