Automobile sound insulation materials

Abstract

The present invention provides a sound insulation material for automobiles, which can maintain light weight and improve rigidity and can exert sufficient sound insulation performance against noise with a frequency of 500 Hz to 5000 Hz generated by automobiles. The sound insulation material for automobiles of the present invention has a multi-layer structure, wherein the multi-layer structure comprises a hard layer (10) and a soft layer (30), wherein the hard layer (10) has cylindrical units arranged in multiple rows, and the soft layer (30) is arranged on one surface of the hard layer, and the ratio of the dynamic spring constant Kd to the static spring constant Ks of the structure of the hard layer (10) and the soft layer (30) is 0<Kd / Ks≦1.5.

Description

Technical Field

[0001] The present invention relates to a sound insulation material for automobiles. Background Art

[0002] The structure of a car generally has an engine room in the front, a trunk room in the rear, and a car compartment in the middle. The car compartment is provided with seats such as a driver's seat, a front passenger seat, and a rear seat. In addition, in the car compartment, a front bulkhead insulator, a carpet, a floor mat, a trunk trim, and a trunk floor are provided in a manner to cover the outside of the car interior parts, and these parts are formed into a concave-convex shape corresponding to the shape of the car body and the design of the parts. In addition, the exterior parts under the car body are provided with a front fender lining, a rear fender lining, and a bottom cover formed into a concave-convex shape to control the air flow. Most of these parts are made of thermoplastic resin, and the material is heated and stamped using a mold in the shape of the part, and finished into a concave-convex part with multiple parts of different thicknesses.

[0003] As a recent trend in automobile development, the quietness of the car interior has received much attention. The noise transmitted to the interior of the car includes noise from the windows, noise from the tires, noise from under the car body, noise from the engine sound, noise from the motor sound, etc. Among the noises, the frequency of 500Hz to 5000Hz is particularly considered to be harsh to the driver and fellow passengers. Therefore, the interior and exterior decorative parts of the car are required to have the function of sound absorption or sound insulation for the noise in this frequency range (band). On the other hand, reducing fuel consumption is also important, and the weight of the interior and exterior decorative parts of the car needs to be reduced.

[0004] In addition, Japanese Patent Publication No. 2009-538746 describes a sandwich component for a sound-absorbing inner cladding of a cell of an aircraft body, the sandwich component having a honeycomb core structure and cover layers applied to both sides of the core structure, the cover layers on both sides respectively having a plurality of channels for transmitting sound waves, a cover formed of a semi-permeable film made of a plastic material is arranged on the cover layer located in the direction of the sound waves, the semi-permeable film made of the plastic material has a plurality of openings with a cross-sectional area, mainly preventing the entry of foreign matter and / or liquid and allowing the transmission of sound waves, and a sound-absorbing layer is formed on the cover layer located in the direction away from the sound waves. Moreover, by such a configuration, a sandwich component having high mechanical load characteristics, light weight, and excellent sound-absorbing characteristics can be provided.

[0005] Prior art literature

[0006] Patent Literature

[0007] Patent Document 1: Japanese Patent Application No. 2009-538746 Summary of the invention

[0008] Problem that the invention aims to solve

[0009] The sandwich component described in the above-mentioned publication is a component that uses a sound absorbing layer to easily absorb noise incident from the direction of the core structure, rather than a component for exerting sound insulation performance. Conventional automobile sound insulation materials use expanded polystyrene (expanded polystyrene) and foamed polyurethane, which are lightweight but have problems such as softness and lack of rigidity.

[0010] Therefore, an object of the present invention is to provide a sound insulating material for an automobile which can maintain its weight and improve its rigidity and can exhibit sufficient sound insulating performance against noise with a frequency of 500 Hz to 5000 Hz generated by an automobile.

[0011] Means used to solve problems

[0012] In order to achieve the above-mentioned purpose, the present invention is a multi-layered automobile sound insulation material, which has a hard layer and a soft layer, wherein the hard layer has cylindrical units arranged in multiple rows, and the soft layer is arranged on one surface of the hard layer; wherein the ratio of the dynamic spring constant Kd to the static spring constant Ks of the structure of the hard layer and the soft layer is 0<Kd / Ks≦1.5.

[0013] The tubular unit may be a polygonal tubular shape such as a roughly quadrangular tubular shape or a roughly hexagonal tubular shape, or may be a curved tubular shape such as a roughly cylindrical shape or a roughly elliptical tubular shape. Preferably, each of the units of the hard layer has a closed surface at one end and an open end at the other end, the internal space of the unit is connected to the outside through the open end of the unit, and the open ends of the unit are arranged on both surfaces of the hard layer in a row with a row of adjacent units between them. The open end, the closed surface on one side, and the closed surface on the other side may be a polygonal shape such as a roughly quadrilateral or roughly hexagonal shape, or may be a curved shape such as a roughly circular or roughly elliptical shape, depending on the shape of the unit.

[0014] The static spring constant Ks of the structure of the hard layer and the soft layer is preferably 20 N / mm or more, and the ratio of the dynamic spring constant Kd to the static spring constant Ks is preferably 0.7<Kd / Ks≦1.5.

[0015] The structure may include a film layer, a fiber layer, or a combination thereof as an additional layer between the hard layer and the soft layer. In this case, the dynamic spring constant Kd and the static spring constant Ks are spring constants of the structure including a film layer, a fiber layer, or a combination thereof between the hard layer and the soft layer. The spacing Pcy between the units in the direction of the row formed by the adjacent units of the hard layer is preferably in the range of 4 mm to 10 mm.

[0016] When a film layer is provided as an additional layer between the hard layer and the soft layer, the thickness of the film layer may be in the range of 50 μm to 300 μm. The film layer may have a plurality of openings penetrating the layer.

[0017] When an additional layer is provided between the film layer and the soft layer, the static spring constant Ks of the additional layer is preferably smaller than the static spring constant Ks of the soft layer. In this case, the material of the soft layer may be foamed polyurethane, the additional layer may be a fiber layer, and the thickness of the fiber layer may be in the range of 0.3 mm to 10 mm.

[0018] Effects of the Invention

[0019] Thus, the automobile sound insulation material of the present invention comprises a hard layer and a soft layer, wherein the hard layer has a cylindrical unit arranged in multiple rows; the soft layer is arranged on at least one surface of the hard layer, and the ratio of the dynamic spring constant Kd to the static spring constant Ks of the structure of the hard layer and the soft layer is 0<Kd / Ks≦1.5; based on this structural configuration, the automobile sound insulation material can be kept lightweight and the rigidity can be improved, and sufficient sound insulation performance can be exerted against the noise generated by the car, because although the noise of 500Hz to 5000Hz generated by the car is transmitted to the car compartment through the vibration of the air or through the vibration of the object, the noise mainly transmitted through the vibration of the object is blocked by the structure of the hard layer and the soft layer. The ratio of the dynamic spring constant to the static spring constant Kd / Ks is called the dynamic magnification (dynamic magnification) in the field of vibration-proof materials, and is generally used as one of the vibration-proof performance indicators. As is well known, the hard layer of the present invention has been used as a core layer in the automobile sound-absorbing material in the past, and has the function of absorbing the noise generated by the car. In the present invention, a hard core layer (hard layer) having tubular units arranged in multiple rows is bonded to a soft soft layer, and a ratio Kd / Ks of a dynamic spring constant to a static spring constant of the structure of the hard layer and the soft layer is set to be less than 1.5 (which is significantly lower than the value of an automotive absorbent material using a conventional core layer). This can block noise mainly transmitted through the vibration of an object, thereby achieving sufficient sound insulation performance against noise generated by the automobile.

[0020] Each unit of the hard layer has a closed surface at one end and an open end at the other end. The internal space of the unit is connected to the outside through the open end of the unit. The open ends of the unit are arranged on both surfaces of the hard layer in a row with adjacent units separated by a row. Based on this structural configuration, it is possible to ensure that the closed surface of the unit of the hard layer becomes the surface for bonding to the soft layer, and the closed surface of the unit is arranged in a row separated by a row, thereby improving the adhesion between the soft layer. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] Figure 1This is a perspective view showing a process of manufacturing a core material used for a hard layer of the automobile sound insulating material of the present invention.

[0022] Figure 2 This is a schematic plan view showing the hard layer of the automobile sound insulating material of the present invention.

[0023] Figure 3 It is represented along line III-III Figure 2 Schematic cross-sectional view of the hard layer.

[0024] Figure 4 This is an exploded perspective view showing one embodiment of the automobile sound insulating material of the present invention.

[0025] Figure 5 yes Figure 4 A schematic cross-sectional view of an embodiment of a sound insulating material for an automobile is shown.

[0026] Figure 6 (a) is a schematic diagram for explaining a method for measuring a static spring constant of a sound insulating material for automobiles of the present invention, Figure 6 (b) is a graph showing the static spring constant obtained from the measured values.

[0027] Figure 7 (a) is a schematic diagram for explaining a method for measuring a dynamic spring constant of a sound insulating material for automobiles of the present invention, Figure 7 (b) is a graph showing the dynamic spring constant obtained from the measured values.

[0028] Figure 8 This is an exploded perspective view showing another embodiment of the automobile sound insulating material of the present invention.

[0029] Fig. 9 This is an exploded perspective view showing still another embodiment of the automobile sound insulating material of the present invention.

[0030] Fig.10 This is an exploded perspective view showing still another embodiment of the automobile sound insulating material of the present invention.

[0031] Fig.11 It is a graph showing the measurement results of the dynamic spring constants of Example 1 and Comparative Example 1 of the automobile sound insulating material of the present invention.

[0032] Fig.12 This is a graph showing the relationship between frequency and insertion loss of Example 1 and Comparative Example 1 of the automobile sound insulating material of the present invention. DETAILED DESCRIPTION

[0033] Hereinafter, one embodiment of the automobile sound insulating material of the present invention will be described with reference to the accompanying drawings. In addition, the accompanying drawings are not intentionally drawn to scale unless otherwise specified.

[0034] First, the hard layer common to each embodiment of the automobile sound insulating material of the present invention will be described. Figure 1 1 is a perspective view showing a manufacturing process of a core material that becomes the hard layer (also referred to as a core layer). In addition, the manufacturing method of the core material is described in detail in International Publication No. 2006 / 053407, which constitutes a part of the description of this specification by reference.

[0035] like Figure 1 As shown, the core material 1 is formed by plastic deformation by thermoforming a flat sheet with a roller (not shown) having a specified mold without substantially cutting the sheet. The material of the core material 1 can be, for example, thermoplastic resins such as polypropylene (PP), polyethylene (PE), polyethylene terephthalate (PET), composite materials with fibers, paper, metal, etc., and thermoplastic resins are particularly preferred, but are not limited to these. In this embodiment, the case of using thermoplastic resins is described. The thickness of the sheet is preferably in the range of 0.05 mm to 0.50 mm, for example, but is not limited to this, and the thickness of the core material 1 after thermoforming is also approximately the same.

[0036] The core material 1 has a three-dimensional structure in which the peaks 11 and the valleys 12 are alternately arranged in the width direction X orthogonal to the manufacturing direction Y. The peak 11 is composed of two side surfaces 13 and a top surface 17 therebetween, and the valley 12 is composed of two side surfaces 13 shared with the adjacent peaks 11 and a bottom surface 14 therebetween. Figure 1 The case where the shape of the mountain portion 11 is a trapezoid is described below, but the present invention is not limited thereto. In addition to polygons such as triangles and rectangles, the shape of the mountain portion 11 may also be a curved shape such as a sine curve or an arc.

[0037] The core material 1 has the three-dimensional structure that is continuous in the manufacturing direction Y. Figure 1 As shown, a plurality of peaks 11a, 11b, 11c, and 11d are continuously formed in the manufacturing direction Y. The valleys 12 are also continuously formed. Furthermore, the connection between the peaks 11 and the connection between the valleys 12 are achieved by alternately repeating two connection methods.

[0038] The first connection method is Figure 1 As shown in FIG. 1 , on the first folding line X1 in the width direction, the top surfaces 17b and 17c of the two adjacent mountain portions 11b and 11c are connected by the mountain portion connecting surfaces 15b and 15c of the trapezoidal shape, respectively. The mountain portion connecting surface 15 is formed at a right angle to the top surface 17. On the first folding line X1 in the width direction, the bottom surfaces 14b and 14c of the two adjacent valley portions are directly connected. The second connection method is as follows Figure 1As shown, on the second folding line X2 in the width direction, the bottom surfaces 14a, 14b (or 14c, 14d) of two adjacent valleys are connected by trapezoidal valley connecting surfaces 16a, 16b (or 16c, 16d), respectively. The valley connecting surface 16 is formed at a right angle to the bottom surface 14. On the second folding line X2 in the width direction, the top surfaces 12a, 12b (or 12c, 12d) of two adjacent mountain portions are directly connected.

[0039] In this way, the multiple three-dimensional structures (mountains 11, valleys 12) of the core material 1 are connected by connecting areas (mountain connecting surfaces 15, valley connecting surfaces 16), and the hard layer of the automobile sound insulation material of the present invention is formed by folding the connecting areas. Specifically, the core material 1 is folded at the first folding line X1 by the mountain folding method so that the bottom surfaces 14b, 14c of the two adjacent valleys overlap with each other through their back surfaces and the angle formed by the mountain connecting surfaces 15b, 15c of the two adjacent mountains is opened to 180 degrees. In addition, the core material 1 is folded at the second folding line X2 by the valley folding method so that the top surfaces 17a, 17b (or 17c, 17d) of the two adjacent mountains overlap with each other and the angle formed by the valley connecting surfaces 16a, 16b (or 16c, 16d) of the two adjacent valleys is closed to 180 degrees. Figure 2 and Figure 3 The hard layer 10 of the automobile sound insulating material of the present invention obtained by folding the core material 1 in this manner is shown.

[0040] like Figure 2 and Figure 3 As shown, the hard layer 10 includes substantially hexagonal cylindrical units 20 arranged in a plurality of rows, and units 20A, 20C, and 20E formed by two adjacent mountain portions and units 20B and 20D formed by two adjacent valley portions are arranged in alternate rows. Figure 3 (and Figure 2 The dotted line 18 in FIG. 1 schematically shows the inner wall of the unit 20 which is the back surface of the core material and is substantially in the shape of a hexagonal cylinder.

[0041] The units 20A, 20C, and 20E formed by the mountain portions each have six unit side walls forming a substantially hexagonal cylindrical shape, and these unit side walls are formed by two top surfaces 17 and four side surfaces 13 of the unit material. In addition, these units 20A, 20C, and 20E are formed on one surface 10a ( Figure 2The unit ends of the hard layer 10 (surface on the surface side) are respectively provided with approximately hexagonal cylindrical closed surfaces 21A, 21C, 21E for closing the unit ends, and these closed surfaces 21 on one side are respectively formed by two trapezoidal mountain connecting surfaces 15 of the unit material. In addition, these units 20A, 20C, 20E are provided with open ends 22A, 22C, 22E opened in an approximately hexagonal shape at the unit ends of the other surface 10b as the opposite side of the hard layer 10. The internal space of each unit 20A, 20C, 20E is connected to the outside through the open ends 22A, 22C, 22E.

[0042] The units 20B and 20D formed by the valleys also have six unit side walls that form a roughly hexagonal cylindrical shape, respectively, and these unit side walls are formed by two bottom surfaces 14 and four side surfaces 13 of the unit material. In addition, these units 20B and 20D have open ends 22B and 22D that open into a roughly hexagonal shape at the unit end of the one surface 10a of the hard layer 10. The internal space of each unit 20B and 20D is connected to the outside through the open ends 22B and 22D. In addition, these units 20B and 20D have roughly hexagonal cylindrical closed surfaces 21B and 21D that close the unit end at the unit end of the other surface 10b of the hard layer 10 as the opposite side, and these closed surfaces 21 on the other side are respectively formed by two trapezoidal valley connection surfaces 16 of the unit material.

[0043] In this way, the hard layer 10 has a side closed surface 21A, 21C, 21E formed by the mountain portion of the unit material in every other row at the unit end of one surface 10a, and has another side closed surface 21B, 21D formed by the valley portion of the unit material in the unit end of the other surface 10b in a row of units different from the above, but unless otherwise recorded, either one side closed surface 21 or the other side closed surface essentially performs the same function.

[0044] The thickness of the hard layer 10 as a whole varies depending on the part of the automobile in which the multilayer structure is used; therefore, although not limited to the following, from the perspective of controlling the ratio Kd / Ks of the dynamic spring constant to the static spring constant of the structure of the hard layer and the soft layer described later, the sound absorbing performance of the hard layer 10 itself, the strength of the hard layer 10, and the weight, it is preferably in the range of 3 mm to 50 mm, and more preferably in the range of 5 mm to 30 mm.

[0045] The basis weight (weight per unit area) of the hard layer 10 varies depending on where the multilayer structure is used in the automobile, and is preferably 400 g / m 2 ~4000g / m 2 The range is more preferably 500g / m 2 ~3000g / m 2The greater the thickness of the hard layer 10 and the greater the basis weight, the higher the strength of the hard layer 10 in general.

[0046] The basis weight of the hard layer 10 can be adjusted by the type of material of the hard layer 10, the thickness of the hard layer 10 as a whole, the wall thickness of the unit 20 (the thickness of the sheet), and can also be adjusted by the spacing Pcx and Pcy (the distance between the central axes of the units) between the units 20 of the hard layer 10. In order to make the basis weight of the hard layer 10 within the above range, for example, the spacing Pcy between the units 20 in the manufacturing direction Y of the core, that is, the direction in which the units 20 are adjacent and form a row, is preferably in the range of 2mm to 20mm, and more preferably in the range of 3mm to 15mm. In particular, in order to control the ratio Kd / Ks of the dynamic spring constant to the static spring constant described later within a specified range, it is further preferred that the spacing Pcy between the units 20 is in the range of 4mm to 10mm.

[0047] Next, each embodiment of the automobile sound insulating material of the present invention will be described using the hard layer 10 described above.

[0048] (First Embodiment)

[0049] like Figure 4 as well as Figure 5 As shown in FIG. 1 , the automobile sound insulating material of the first embodiment includes: the hard layer 10 described above; the soft layer 30 provided on one surface of the hard layer 10; and the skin layer 50 provided on the other surface of the hard layer 10. The automobile sound insulating material of the present invention is used in such a manner that the soft layer 30 side is located on the side of the noise generation source; that is, the automobile sound insulating material of the present invention is provided on the vehicle interior side in such a manner that the soft layer 30 is provided on the panel 100 side of the vehicle body.

[0050] For the soft layer 30, since it is softer than the hard layer 10 and the hard layer 10 (also referred to as the core layer) has a cylindrical unit arranged in multiple rows and has a hard property, it is referred to as the soft layer in this specification. There is no particular limitation on the material of the soft layer 30, as long as it is a material commonly used for the sound insulation layer in the sound insulation material for automobiles, but from the perspective of lightweight sound insulation materials for automobiles, preferably, foams such as thermoplastic resins such as foamed polyurethane, foamed polyethylene, and foamed nylon, thermosetting resins, and other foams, and also preferably synthetic fibers such as polyester fibers, nylon fibers, acrylic fibers, inorganic fibers such as glass wool, rock wool, and metal fibers such as aluminum fibers. As a fiber, it is preferably felt and is preferably formed by raw materials such as polyester fibers such as low-melting polyester fibers, glass wool, etc. In addition, as a method for making felt, it is preferably a felt made by a method such as a needle punching method, a hot rolling method, and a spunlace method. In addition, the soft layer 30 can also be combined with a foam and a fiber.

[0051] The basis weight of the soft layer 30 is determined by the ratio of the dynamic spring constant to the static spring constant Kd / Ks described below; therefore, although not limited to the following, the lower limit of the basis weight of the soft layer 30 is preferably 200 g / m 2 More preferably 300g / m 2 More preferably, 500 g / m 2 In addition, the upper limit of the basis weight is preferably 2000 g / m 2 Below, more preferably 1500g / m 2 Below, more preferably 1200g / m 2 the following.

[0052] The thickness of the soft layer 30 depends on the ratio Kd / Ks of the dynamic spring constant to the static spring constant described later; therefore, although not limited to the following, for example, the lower limit of the thickness of the soft layer 30 is preferably 4 mm or more, more preferably 7 mm or more, and further preferably 10 mm or more. In addition, the upper limit of the thickness is preferably 50 mm or less, more preferably 40 mm or less, and further preferably 30 mm or less.

[0053] In the present embodiment, the ratio of the dynamic spring constant Kd to the static spring constant Ks of the structure of the hard layer 10 and the soft layer 30 satisfies 0<Kd / Ks≦1.5. The ratio Kd / Ks of the dynamic spring constant to the static spring constant is called the dynamic magnification (dynamic magnification) in the field of vibration-proof materials, and is generally used as one of the indicators of vibration-proof performance. In the present invention, the ratio Kd / Ks of the dynamic spring constant to the static spring constant of the structure of the hard layer 10 and the soft layer 30 is made to be 1.5 or less, which is significantly lower than the value of the automotive sound-absorbing material using the conventional core layer. The noise of the frequency of 500Hz to 5000Hz generated by the car is transmitted to the cabin through the vibration of the air or through the vibration of the object, but the noise mainly transmitted by the vibration of the object can be blocked by the structure of the hard layer 10 and the soft layer 30, so that the noise generated by the car can be fully soundproofed. The ratio Kd / Ks of the dynamic spring constant to the static spring constant is more preferably 1.4 or less, and more preferably 1.0 or less. On the other hand, if the ratio Kd / Ks of the dynamic spring constant to the static spring constant is too low, vibration occurs at a low frequency, making it unsuitable as a sound insulation material for automobiles. Therefore, the lower limit of the ratio Kd / Ks of the dynamic spring constant to the static spring constant needs to be greater than 0, preferably greater than 0.5, and more preferably greater than 0.7.

[0054] In particular, when the ratio of the dynamic spring constant to the static spring constant Kd / Ks is 0.7 or more, in order to maintain the shape, the static spring constant Ks of the structure of the hard layer 20 and the soft layer 30 is preferably 20 N / mm or more, more preferably 25 N / mm or more. There is no particular limitation on the upper limit of the static spring constant Ks of the structure, but it is preferably 50 N / mm or less, more preferably 30 N / mm or less. In addition, there is no particular limitation on the dynamic spring constant Kd of the structure, but the lower limit is preferably 2 N / mm or more, more preferably 10 N / mm or more, and the upper limit is preferably 80 N / mm or less, more preferably 50 N / mm or less.

[0055] The ratio Kd / Ks of the dynamic spring constant to the static spring constant of the structure of the hard layer 10 and the soft layer 30 can be obtained by the following method. First, the static spring constant Ks and the dynamic spring constant Kd of the structure of the hard layer 10 and the soft layer 30 are measured respectively based on JIS K 6385 and JIS K 6394. Specifically, in the measurement of the static spring constant Ks (N / mm): Figure 6 As shown in (a), a compression device (not shown) is used to compress the sample of the structure of the hard layer 10 and the soft layer 30 from the compression direction 60 with a load F (N), and the displacement x (mm) of the thickness of the sample at this time is measured; Figure 6 As shown in (b), a displacement-to-load curve (Ks=F / x) is prepared, and the static spring constant Ks is calculated based on the slope of the linear range of the curve. In the measurement of the dynamic spring constant Kd (N / mm), as Figure 7 As shown in (a), a sample of a structure of a hard layer 10 and a soft layer 30 is sandwiched between a mass plate 72 and set to a specified mass m, an accelerometer 70 is set on the hard layer 10 side, and an exciter 74 is set on the soft layer 30 side, and the acceleration amplitude is measured at a frequency between 10 Hz and 400 Hz with an acceleration amplitude of 0.1 m / s 2 The vibration level of the case where it is vibrated. Figure 7 As shown in (b), a graph of vibration level versus frequency is made, and the frequency of resonance f is obtained. According to the formula Kd=(2πf) 2 × m, the dynamic spring constant Kd is calculated. Furthermore, the ratio (Kd / Ks) of the static spring constant Ks and the dynamic spring constant Kd thus obtained is calculated. For example, the static spring constant Ks can be measured using a commercially available tensile and compression testing machine (manufactured by Shimadzu Corporation, AG-20kNX). For example, the dynamic spring constant Kd can be measured using a combination of a commercially available electromagnetic exciter (manufactured by AR BROWN, VG-100) and a vibration measuring device (manufactured by LMS, Test.Lab).

[0056] The static spring constant Ks and the dynamic spring constant Kd vary depending on the composition of the soft layer 30 (e.g., the type of material, basis weight, thickness, etc.), and are also affected by the composition of the hard layer 10 provided with the soft layer 30 (e.g., the material, the arrangement of the units, the thickness of the entire hard layer, the spacing between the units, the thickness of the unit wall, etc.). There is no particular limitation on the static spring constant Ks of the soft layer 30, but the lower limit is preferably 20 N / mm or more, more preferably 25 N / mm or more, and the upper limit is preferably 80 N / mm or less, more preferably 50 N / mm or less.

[0057] The surface layer 50 is a layer that becomes the surface of the interior of the vehicle when the automobile sound insulation material of this embodiment is provided on the panel 100 of the vehicle body. The surface layer 50 may be a blanket, foamed polyurethane, or the like that is generally used as the surface layer of the automobile sound insulation material or automobile sound absorbing material. As the material of the blanket, for example, polyester fiber, natural fiber, or the like may be used as the main material. As the method for manufacturing the blanket, for example, a needle punching method may be used. As the surface density of the blanket, it is preferably 800 to 2000 g / m 2 range.

[0058] Based on the first embodiment, by providing a soft layer 30 on one surface of a hard layer 10 having an open end and a closed surface arranged in a row, and providing a skin layer 50 on the other surface of the hard layer 10, and making the ratio Kd / Ks of the dynamic spring constant to the static spring constant within the above-mentioned numerical range, it is possible to maintain the lightweight and improve the rigidity of the automobile sound insulation material, while blocking the noise with a frequency of 500 Hz to 5000 Hz generated by the automobile, and also blocking the noise mainly transmitted through the vibration of the object, so that sufficient sound insulation performance can be exerted.

[0059] (Second Embodiment)

[0060] like Fig. 9 (and Figure 8 As shown in the related document, the automobile sound insulation material of the second embodiment includes: the above-mentioned hard layer 10; the soft layer 30 provided on one surface of the hard layer 10 via the film layer 80 as an additional layer; and the skin layer 50 provided on the other surface of the hard layer 10. In addition, the same symbols (figure marks, etc.) are attached to the same structures as those in the first embodiment, and detailed descriptions are omitted here.

[0061] In the second embodiment, a film layer 80 is provided between the hard layer 10 and the soft layer 30. In this case, the ratio Kd / Ks of the dynamic spring constant to the static spring constant of the structure of the hard layer 10 and the soft layer 30 is calculated based on the dynamic spring constant Kd and the static spring constant Ks obtained by the above-mentioned measurement method for the structure of the hard layer 10 and the soft layer 30 sandwiched by the film layer 80. If the ratio Kd / Ks of the dynamic spring constant to the static spring constant calculated in this way is within the above-mentioned prescribed numerical range, the same sound insulation effect as that of the first embodiment can be obtained.

[0062] The material of the film layer 80 may be, for example, a resin film such as polypropylene (PP), polyethylene (PE), polyethylene terephthalate (PET), or polyamide (PA), but is not limited thereto.

[0063] The thickness of the film layer 80 is not particularly limited as long as the ratio Kd / Ks of the dynamic spring constant to the static spring constant of the structure of the hard layer 10 and the soft layer 30 is kept within a specified range. For example, the lower limit of the thickness of the film layer 80 is preferably 0.03 mm or more, more preferably 0.04 mm or more, and further preferably 0.05 mm or more. In addition, the upper limit of the thickness is preferably 0.5 mm or less, more preferably 0.4 mm or less, and further preferably 0.3 mm or less.

[0064] The film layer 80 may be bonded to the hard layer 10 and the soft layer 30 by heat fusion, or may be bonded to the hard layer 10 and the soft layer 30 by an adhesive (not shown). There is no particular limitation on the adhesive, and for example, epoxy and acrylic adhesives may be used. In addition, in order to heat-fusion-bond the epidermis layer 50 to the hard layer 10 and the soft layer 30, for example, the epidermis layer 50 may be made into a three-layer structure, including a central layer and two adhesive layers on the surfaces of both sides of the central layer. In this case, the material of the adhesive layer uses a material having a lower melting point than the material used for the central layer. For example, by using polyamide having a melting point of 190°C to 220°C for the central layer and polyethylene having a melting point of 90°C to 130°C for the adhesive layer, the temperature of heating when bonding the skin layer 50 to the hard layer 10 and the soft layer 30 and the temperature of thermoforming the automobile sound insulation material into a predetermined shape are set to about 150°C to 160°C, so that the central layer does not melt and only the adhesive layer melts, thereby firmly bonding the skin layer 50 to the hard layer 10 and the soft layer 30. In addition to polyamide, polypropylene is also a resin having a higher melting point than the polyethylene of the adhesive layer.

[0065] The film layer 80 can be a breathable film layer having multiple openings running through the layer, or it can be a non-breathable film layer without such openings. In the case of having openings, the openings can be made in advance before the film layer 80 is bonded to the hard layer 10, for example, by a hot needle or punching process (punching process using a male mold and a female mold). In order to prevent the holes from being blocked, the hole shape is preferably one that minimizes the burrs of the holes. The opening pattern is preferably arranged in a staggered arrangement or a grid arrangement, but there is no particular limitation. The porosity of the film layer 80 is preferably in the range of 0.2% to 5%, but there is no particular limitation. The diameter of the opening is preferably in the range of 0.25 mm to 2.5 mm, and more preferably in the range of 0.3 mm to 2.0 mm. In addition, the spacing between the openings of the film layer 80 and Figure 2 The pitches Pcx and Pcy of the units 20 of the hard layer 10 shown do not need to be consistent; in addition, when the film layer 80 and the hard layer 10 are attached, it is not necessary to align the openings and the units 20. This is because by randomly overlapping the positions of the openings of the film layer 80 and the open ends 22 of the units 20 of the hard layer 10, it is possible to appropriately ensure the communication between the inside and the outside. The pitch of the openings of the film layer 80 is preferably smaller than the pitch of the units 20 of the hard layer 10 in at least one of the X direction and the Y direction.

[0066] According to the second embodiment, by providing the film layer 80 between the hard layer 10 and the soft layer 30, which are arranged with an open end and a closed surface in a row, the same effect as the first embodiment can be obtained, and the effect of sound absorption or sound insulation can also be obtained by the film layer 80. In particular, by providing a plurality of openings in the film layer 80, sound absorption can be achieved.

[0067] (Third Embodiment)

[0068] like Fig. 9 As shown, the automobile sound insulation material of the third embodiment includes: the above-mentioned hard layer 10; the soft layer 30 provided on one surface of the hard layer 10 via the first film layer 80a; and the skin layer 50 provided on the other surface of the hard layer 10 via the second film layer 80b. In addition, the same symbols (reference numerals, etc.) are attached to the same structures as those of the first and second embodiments, and detailed descriptions are omitted here.

[0069] The first film layer 80a and the second film layer 80b can use the same configuration structure (material, thickness, layer structure, presence or absence of openings, etc.) as the film layer 80 described in the second embodiment. The first film layer 80a and the second film layer 80b can use film layers of the same structure, or they can use film layers of different structures. The third embodiment is also similar to the second embodiment, based on the dynamic spring constant Kd and the static spring constant Ks obtained by the above-mentioned measurement method for the structure of the hard layer 10 and the soft layer 30 separated by the first film layer 80a, the ratio Kd / Ks of the dynamic spring constant to the static spring constant of the structure of the hard layer 10 and the soft layer 30 is calculated.

[0070] Based on the third embodiment, the same effect as the second embodiment can be obtained, and by providing the second film layer 80b between the hard layer 10 and the skin layer 50 separated by a row of open ends and closed surfaces, the second film layer 80b can also absorb or insulate sound.

[0071] (Fourth Embodiment)

[0072] like Fig.10 As shown, the automobile sound insulating material of the fourth embodiment includes: the above-mentioned hard layer 10; a soft layer 30 provided on one surface of the hard layer 10 via a film layer 80 and a fiber layer 90 as additional layers in this order; and a skin layer 50 provided on the other surface of the hard layer 10. In addition, the same symbols (reference numerals, etc.) are attached to the same structures as those of the first and second embodiments, and detailed descriptions thereof are omitted here.

[0073] In the fourth embodiment, a film layer 80 and a fiber layer 90 are provided between the hard layer 10 and the soft layer 30. In this case, the ratio Kd / Ks of the dynamic spring constant to the static spring constant of the structure of the hard layer 10 and the soft layer 30 is calculated based on the dynamic spring constant Kd and the static spring constant Ks obtained by the above-mentioned measurement method for the structure of the hard layer 10 and the soft layer 30 sandwiched by the film layer 80 and the fiber layer 90. If the ratio Kd / Ks of the dynamic spring constant to the static spring constant calculated in this way is within the above-mentioned prescribed numerical range, the same sound insulation effect as that of the first embodiment can be obtained.

[0074] There is no particular limitation on the fiber layer 90 as long as the ratio Kd / Ks of the dynamic spring constant to the static spring constant is maintained within a specified range. For example, various nonwoven fabrics such as spunbond, spunlace or needle-punched fabrics using resin fibers such as polyethylene terephthalate (PET), polypropylene (PP) and polyethylene (PE) are preferably used. There is no particular limitation on the basis weight of the fiber layer 90 as long as the ratio Kd / Ks of the dynamic spring constant to the static spring constant is maintained within a specified range. For example, it is preferably 10 g / m 2~600g / m 2 The range is more preferably 20g / m 2 ~500g / m 2 The range is preferably 30 g / m 2 ~300g / m 2 range.

[0075] In particular, in order to make vibration difficult to conduct, the static spring constant Ks of the laminate of the film layer 80 and the fiber layer 90 as the additional layer is preferably smaller than the static spring constant Ks of the soft layer 30. For example, there is no particular limitation on the static spring constant Ks of the laminate as the additional layer, but the lower limit is preferably 0.1 N / mm or more, more preferably 0.5 N / mm or more, and the upper limit is preferably 30 N / mm or less, more preferably 20 N / mm or less.

[0076] In addition, Fig.10 , a laminate of a film layer 80 and a fiber layer 90 as an additional layer is shown, but the additional layer may be only the fiber layer 90. In this case, the static spring constant Ks of the fiber layer 90 is preferably smaller than the static spring constant Ks of the soft layer 30. For example, there is no particular limitation on the static spring constant Ks of the fiber layer 90, but the lower limit is preferably 0.1 N / mm or more, more preferably 0.5 N / mm or more, and the upper limit is preferably 30 N / mm or less, more preferably 20 N / mm or less. As the material of the soft layer 30 in this case, foamed polyurethane can be used. In addition, as for the thickness of the fiber layer 90 in this case, in order to make it difficult for vibration to be conducted, the lower limit is preferably 0.3 mm or more, more preferably 1 mm or more, and the upper limit is preferably 10 mm or less, more preferably 5 mm or less.

[0077] According to the fourth embodiment, by providing a film layer 80 and a fiber layer 90 between a hard layer 10 and a soft layer 30, which are arranged with an open end and a closed surface in a row, the same effect as the first embodiment can be obtained, and the film layer 80 and the fiber layer 90 as additional layers can absorb sound. In addition, when the additional layer is only the fiber layer 90, the effect of being able to be more lightweight can be obtained.

[0078] Example

[0079] Next, examples of the present invention and comparative examples are described.

[0080] As Example 1, a Fig.10 The multi-layered sound insulation material for automobiles shown in FIG. Figure 1 to Figure 3The hard layer (made of polypropylene (PP) resin, with a unit spacing Pcy of 8 mm and a hard layer thickness of 10 mm) is laminated to one surface of the structure in sequence with a film layer (made of open-pore polypropylene (PP) film with a thickness of 50 μm) and a fiber layer (made of PP needle-punched nonwoven fabric with a basis weight of 15 g / m 2 ) and soft layer (material is foamed polyurethane (PU), basis weight is 1000g / m 2 The static spring constant Ks of the structure of the hard layer, membrane layer, fiber layer and soft layer was measured by a tensile and compression testing machine (manufactured by Shimadzu Corporation, AG-20kNX) (compression terminal speed was 50 mm / min, compression ratio was within 20%), and a combination of an electromagnetic exciter (manufactured by AR BROWN, VG-100) and a vibration measuring device (manufactured by LMS, Test.Lab) (frequency was 10 to 400 Hz, acceleration amplitude was 0.1 m / s 2 , mass m is 0.0232kg) and the dynamic spring constant Kd was measured. The results are shown in Table 1. As shown in Table 1, the static spring constant Ks is 27.5N / mm and the dynamic spring constant Kd is 27.7N / mm. Therefore, the ratio of the dynamic spring constant to the static spring constant Kd / Ks is 1.0. In addition, the static spring constant Ks of the fiber layer and the soft layer were measured separately using the same steps as above. The results are shown in Table 1. The static spring constant Ks of the membrane layer was not measured here because its influence was so small that it could be ignored.

[0081] In addition, the curve graph of the results obtained by measuring the dynamic spring constant Kd is shown in Fig.11 As shown in Fig.11 As shown, in Example 1, based on the resonance frequency f of 56.75 Hz, the measurement result and the mass m of 0.0232 kg (0.23 N) are substituted into the above formula Kd = (2πf) 2 × m, and the value of Kd can be obtained from this.

[0082] Next, the insertion loss of the four-layer structure of the hard layer, film layer, fiber layer, and soft layer of Example 1 was measured. Insertion loss is an indicator of the sound insulation performance improved by installing a sound insulation material on a substrate such as a panel. Specifically, if the sound transmission loss of the state where only the panel of the car is used as the substrate is TL panel The sound transmission loss of the panel with the structure and the skin layer as the sound insulation material is TL panel-trim , then according to the formula IL trim =TL Panel-trim -TL Panel The insertion loss (IL) of the above structure as a sound insulation material is derived.trim ).

[0083] The sound transmission loss between 200 Hz and 5000 Hz was measured for each state of the base and the state in which the above structure was installed. The insertion loss was calculated based on the above equation from the measurement results. Fig.12 In addition, the sound transmission loss was measured by combining a reverberation chamber and an anechoic chamber and measuring the sound intensity. The relationship between the sound transmission loss and each measured value is shown in the following formula. The size of the measurement sample is 500 mm × 600 mm.

[0084] TL=SPL0-PWL i +10log 10 S-6

[0085] TL: Transmission loss (dB)

[0086] SPL0: Average sound pressure level in the reverberation room (dB)

[0087] PWL i : Power level of transmitted sound (dB)

[0088] S: Sample area (m 2 )

[0089] In addition, for comparison, Comparative Example 1 was made in the same manner as Example 1 except that expanded polystyrene (EPS) (10 mm thick) was used instead of the hard layer and the film layer and fiber layer were omitted. The static spring constant Ks and dynamic spring constant Kd were measured in the same manner as Example 1. The results are shown in Table 1 and Fig.11 In addition, for Comparative Example 1, the insertion loss was measured in the same manner as in Example 1. The results are shown in Fig.12 Shown in.

[0090] like Fig.11 As shown in FIG. 1 , in Comparative Example 1, the resonance frequency f is 76.5 Hz, and the dynamic spring constant Kd is 52.6 N / mm, which is much higher than that of Example 1. The static spring constant Ks is 25 N / mm, which is a value close to that of Example 1, but the ratio of the dynamic spring constant to the static spring constant Kd / Ks is as high as 2.1. Fig.12As shown, it can be confirmed that the insertion loss of Example 1, in which the ratio of the dynamic spring constant to the static spring constant Kd / Ks is 1.0, is higher by about 3 dB or more in the crossover frequency range of 500 to 5000 Hz than that of Comparative Example 1, in which the ratio of the dynamic spring constant to the static spring constant Kd / Ks is 2.1, showing excellent sound insulation performance. In addition, since Comparative Example 1 is a structure of foamed polyurethane and foamed polystyrene, both are soft and lack rigidity as a sound insulation material as a whole; on the other hand, Example 1 uses a hard and lightweight core layer having a cylindrical unit arranged in multiple rows as a hard layer instead of the foamed polystyrene of the comparative example, so that as a sound insulation material as a whole, it can maintain lightness and improve rigidity.

[0091] As Examples 2 to 6, as shown in Table 1, the spacing Pcy between the core cells of the hard layer was changed, and the material of the soft layer was changed to felt (the material was mixed cotton, the basis weight was 600 g / m 2 ), no film layer or fiber layer was provided between them, or a non-permeable film without openings was used as the film layer, the thickness was changed, and the basis weight of the fiber layer was changed. A structure that became a sound insulation material was prepared in the same manner as in Example 1, and the static spring constant Ks and the dynamic spring constant Kd were measured. In addition, as Comparative Examples 1 and 2, as shown in Table 1, the static spring constant Ks and the dynamic spring constant Kd were measured in the same manner as in Example 1, except that only the soft layer of Examples 1 and 6 was used as the structure. These results are shown in Table 1.

[0092] [Table 1]

[0093]

[0094] As shown in Table 1, even in Examples 2 and 3 in which neither a film layer nor a fiber layer is provided between the hard layer and the soft layer, the ratio Kd / Ks of the dynamic spring constant to the static spring constant can be made less than 1.5. In addition, even in Examples 4 to 6 in which the film layer, the fiber layer or the soft layer is changed respectively, the ratio Kd / Ks of the dynamic spring constant to the static spring constant can be reduced to less than 1.5. On the other hand, for Comparative Example 2 having only foamed polyurethane, the dynamic spring constant Kd is higher than that of Comparative Example 1, and the ratio Kd / Ks of the dynamic spring constant to the static spring constant is as high as 2.4. In addition, for Comparative Example 3 having only felt, the dynamic spring constant Kd is greatly reduced compared with Comparative Examples 1 and 2, but the static spring constant Ks is also greatly reduced, and the ratio Kd / Ks of the dynamic spring constant to the static spring constant is a very high 4.8. Comparative Examples 1 to 3 having only such a soft layer have low rigidity and a ratio Kd / Ks of a dynamic spring constant to a static spring constant exceeding 1.5, so that the sound insulation performance at a frequency of 500 to 5000 Hz is inferior to that of the examples.

[0095] Industrial Applicability

[0096] The automobile soundproofing material of the present invention can achieve sufficient soundproofing performance while maintaining light weight and improving rigidity by means of the hard layer and the soft layer. More specifically, the automobile soundproofing material of the present invention is useful as a component for isolating noise between a noise source such as a carpet, a floor mat, a trunk trim, a trunk floor, a front bulkhead insulator, and an undercover and the interior of a vehicle cabin (inside a vehicle interior).

[0097] Description of Reference Numerals

[0098] 1: Core material

[0099] 10: Hard layer (core layer)

[0100] 11: Yamabe

[0101] 12: Tanibe

[0102] 13: Side face

[0103] 14: Bottom

[0104] 15: Mountain connection surface

[0105] 16: Valley connection surface

[0106] 17: Top surface

[0107] 18: Back side of core material

[0108] 20: Unit

[0109] 21: Closed surface

[0110] 22: Open end

[0111] 30: Soft layer

[0112] 50: Epidermis

[0113] 60: Compression direction

[0114] 70: Accelerometer

[0115] 72: Quality Board

[0116] 74: Vibrator

[0117] 80: Film layer

[0118] 90: Fiber layer

[0119] 100: Panel

Claims

1. A sound-insulating material for automobiles, which is a multi-layered sound-insulating material for automobiles, and comprises a core layer, a soft layer, and a skin layer, wherein the core layer has cylindrical units arranged in multiple rows, the soft layer is provided on one surface of the core layer and is softer than the core layer, and the skin layer is provided on the other surface of the core layer and is a layer of the surface of the sound-insulating material for automobiles on the inner side of the vehicle compartment; wherein: Each of the cells of the core layer has a closed surface at one end and an open end at the other end, and the open ends of the cells are arranged on both surfaces of the core layer in a manner that the cells are separated by a row of adjacent cells. The structure composed of the core layer and the soft layer has a ratio of a dynamic spring constant Kd to a static spring constant Ks of 0<Kd / Ks≦1.

5.

2. The automobile sound insulating material according to claim 1, wherein: The structure composed of the core layer and the soft layer has a static spring constant Ks of 20 N / mm or more, and a ratio of the dynamic spring constant Kd to the static spring constant Ks is 0.7<Kd / Ks≦1.

5.

3. The automobile sound insulating material according to claim 1 or 2, wherein: A pitch Pcy between the cells in the core layer in a direction of a row formed by adjacent cells is in a range of 4 mm to 10 mm.

4. The automobile sound insulating material according to claim 1, wherein: A first additional layer is further provided between the core layer and the soft layer, the first additional layer being a film layer, a fiber layer or a combination thereof, and a structure composed of the core layer, the soft layer and the first additional layer having a ratio of a dynamic spring constant Kd to a static spring constant Ks of 0<Kd / Ks≦1.5, When the first additional layer is a film layer, the thickness of the film layer is in the range of 50 μm to 300 μm.

5. The automobile sound insulating material according to claim 4, wherein: The film layer has a plurality of openings extending through the layer.

6. The automobile sound insulating material according to claim 4, wherein: When the first additional layer is the film layer, a second additional layer is further provided between the film layer and the soft layer. The static spring constant Ks of the second additional layer is smaller than the static spring constant Ks of the soft layer, and the ratio of the dynamic spring constant Kd to the static spring constant Ks of the structure composed of the core layer, the soft layer, the film layer and the second additional layer is 0<Kd / Ks≦1.

5.

7. The automobile sound insulating material according to claim 6, wherein: The material of the soft layer is foamed polyurethane, the second additional layer is a fiber layer, and the thickness of the fiber layer is in the range of 0.3 mm to 10 mm.

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