Soundproofing mechanism

Abstract

To provide a vehicle soundproof material and a soundproof mechanism, which are light-weight and thin and have high soundproof performance against sound in a frequency band which is particularly problematic in recent vehicles.SOLUTION: A vehicle soundproof material has a configuration in which a polyurethane foam layer 2 and an elastomer layer 3 are laminated. A storage shear elastic modulus G' at a temperature of 25°C and a frequency of 1 Hz to 2,000 Hz is 5.0×103 Pa or more and 1.0×105 Pa or less, and a loss tangent tan δ at a temperature of 25°C and a frequency of 1 Hz to 2,000 Hz is 0.01 or more and 0.3 or less in the polyurethane foam layer 2, and a density of the elastomer layer 3 is 1,000 kg / m3 or more and 2,000 kg / m3 or less, a thickness of the polyurethane foam layer 2 is 15 mm or less, a thickness of the elastomer layer 3 is 3 mm or less. These layers are arranged on a vehicle panel 5 constituting a part of a vehicle body.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention is defense Regarding sound mechanics. [Background technology]

[0002] In automobiles, soundproofing materials are attached to the body of the automobile to prevent noise from being transmitted to the interior of the passenger compartment. Patent Document 1 discloses a vehicle floor silencer that is placed between the floor panel and the floor carpet to damp vibrations that enter the passenger compartment from below the vehicle body. This vehicle floor silencer is formed from a urethane foam composition that includes polyol, polyisocyanate, a blowing agent, a foam stabilizer, and a catalyst.

[0003] Patent Document 2 discloses a floor sound insulation structure that effectively blocks road noise generated when a vehicle runs on a rough road surface. This sound insulation structure is configured by layering, in order, a urethane layer that has high adhesion to the floor panel, a lower mass layer, a fibrous layer or low-elasticity urethane layer that reduces secondary resonance frequency, an upper mass layer, and carpet on top of the steel vehicle floor panel that constitutes the passenger compartment.

[0004] Patent Document 3 discloses a flexible polyurethane foam used as a vibration damping material, which is obtained from an active hydrogen compound, an organic polyisocyanate composition, a blowing agent, a crosslinking agent, a foam stabilizer, and a catalyst. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] Japanese Patent Application Publication No. 2018-39321 [Patent Document 2] Japanese Patent Application Laid-Open No. 2003-104135 [Patent Document 3] Japanese Patent Application Laid-Open No. 2000-212241 Summary of the Invention [Problem to be solved by the invention]

[0006] The configurations described in Patent Documents 1 to 3 are excellent in vibration damping properties. However, Patent Documents 1 and 3 do not mention sound insulation, and it is unclear whether the configurations in Patent Documents 1 and 3 have sound insulation properties. Patent Document 2 is intended to insulate road noise, but it is unclear what specific frequency of sound the configuration is able to insulate.

[0007] In recent years, as automobiles have become more electrified and engine noise has decreased, noises outside the vehicle (road noise, tire noise, etc.) have become more noticeable than before. Therefore, there is a need to identify the frequencies of the noises outside the vehicle that have become particularly noticeable in recent automobiles and to suppress the transmission of such noises into the vehicle cabin. Furthermore, since a structure for suppressing the transmission of such noises into the vehicle cabin is installed in the automobile, it is preferable that it is lightweight and thin.

[0008] Therefore, an object of the present invention is to provide a lightweight, thin, and highly sound-insulating vehicle body that has high sound insulation properties against sounds in the frequency band that are particularly problematic in modern automobiles. Prevention To provide a sound mechanism. [Means for solving the problem]

[0010] The soundproofing mechanism of the present invention comprises: A two-layer structure consisting of a polyurethane foam layer and an elastomer layer. The present invention has a soundproofing material for an automobile and a vehicle panel that forms part of the body of the automobile, The storage shear modulus G' of the polyurethane foam layer of the soundproofing material at a temperature of 25°C and a frequency of 1 Hz to 2000 Hz is 7.57 × 10 3 Pa or more 3.24×10 4 Pa or less, the loss tangent tanδ is 0.09 or more and 0.27 or less at a temperature of 25°C and a frequency of 1 Hz to 2000 Hz, and the flow resistance per unit thickness of the polyurethane foam layer is 2.09 × 10 4 Ns / m 4 Over 5.93 x 10 4 Ns / m 4 and the density of the polyurethane foam layer is 53 kg / m or less. 3 More than 55kg / m 3 is as follows: The soundproofing material is laminated to the vehicle panel. The soundproofing material may be laminated on the vehicle panel so that the polyurethane foam layer is in contact with the vehicle panel. [Effects of the Invention]

[0011] According to the present invention, a light-weight, thin, and high sound insulation property against sounds in the frequency band that is particularly problematic in recent automobiles is provided. Prevention A sound mechanism can be provided. [Brief explanation of the drawings]

[0012] [Figure 1] 1 is a cross-sectional view showing a soundproofing mechanism including a soundproofing material for an automobile according to one embodiment of the present invention. [Figure 2] FIG. 2 is a side view schematically showing an automobile provided with the soundproofing mechanism shown in FIG. DETAILED DESCRIPTION OF THE INVENTION

[0013] Hereinafter, an embodiment of the present invention will be described with reference to the drawings. Fig. 1 shows the basic structure of a soundproofing mechanism including a soundproofing material 1 according to one embodiment of the present invention. The soundproofing material 1 has a two-layer structure in which an elastomer layer 3 is laminated on a polyurethane foam layer 2. The polyurethane foam layer 2 has a storage shear modulus G' of 5.0 x 10 at a temperature of 25°C and a frequency of 1 Hz to 2000 Hz. 3 Pa or more 1.0×10 5 The elastomer layer 3 is made of polyurethane foam having a density of 1000 kg / m or less, a loss tangent tanδ of 0.01 or more and 0.3 or less at a temperature of 25°C and a frequency of 1 Hz to 2000 Hz. 3 More than 2000kg / m 3 It is made of the following rubber etc. The thickness of the polyurethane foam layer 2 is 15 mm or less, the thickness of the elastomer layer 3 is 3 mm or less, and the thickness of the entire soundproofing material 1 is 18 mm or less.

[0014] This soundproofing material 1 is attached to a vehicle panel (e.g., steel plate 5) that constitutes part of the body of an automobile 4 shown in Fig. 2, specifically, part of the floor (e.g., part A in Fig. 2), to form an automobile soundproofing mechanism (floor carpet (also called a floor silencer) or dash silencer (also called a dash insulator)). By using this soundproofing material 1 to form a soundproofing mechanism, excellent sound insulation is achieved against sounds with frequencies between 500 Hz and 1000 Hz, which are the main frequencies of road noise and tire noise, which are particularly problematic noises in recent automobiles. [Example]

[0015] More specific examples of soundproofing mechanisms including the above-described soundproofing material 1 of the present invention will be described below, along with comparative examples for comparison with each example. For the polyurethane foam layer 2 of the following examples and comparative examples, the dynamic viscoelastic properties (storage shear modulus G' and loss tangent tanδ) and unit thickness flow resistance were determined using the methods described below. Furthermore, for the elastomer layers of the examples and comparative examples of the present invention, the durometer A hardness was determined using the methods described below. The areal density of the soundproofing materials of the examples and comparative examples of the present invention and the sound insulation (sound transmission loss) of the soundproofing mechanisms including these soundproofing materials were then determined using the methods described below.

[0016] <Dynamic viscoelasticity of polyurethane foam layer> For the polyurethane foam layers of the examples and comparative examples of the present invention, the frequency dependence of dynamic viscoelasticity was measured at each temperature under the following conditions using a viscoelasticity measuring device ARES-G2 (trade name) manufactured by TA Instruments Japan Inc. Based on these measurement results, a master curve was created at a reference temperature of 25°C according to the time-temperature conversion law using the analysis software TRIOS (trade name) provided with the measuring device. Based on this, the storage shear modulus G' and loss tangent tanδ were calculated at a temperature of 25°C at each frequency (1 Hz, 100 Hz, 500 Hz, 1000 Hz, 2000 Hz). Deformation mode: Shear Measurement jig: Parallel plate (diameter 8 mm) Frequency: 0.1Hz~10Hz ·Temperature: -30℃, -25℃, -20℃, -15℃, -10℃, -5℃, 0℃, 5℃, 10℃, 15℃, 20℃, 25℃ Distortion: 0.1% to 10% (can be adjusted to detect torque appropriately within the linear range)

[0017] <Flow resistance per unit thickness of polyurethane foam layer> The polyurethane foam layers of the examples of the present invention and the comparative examples were measured for flow resistance per unit thickness [Ns / m 4 ] was requested.

[0018] <Durometer A hardness of elastomer layer> The durometer A hardness of the elastomer layers of the examples of the present invention and the comparative examples was determined in accordance with JIS K6253.

[0019] <Surface density of soundproofing material> The soundproofing materials of the examples of the present invention and the comparative examples were weighed and 2 The surface density can be calculated by converting it into weight per unit area [kg / m 2 ] was requested.

[0020] <Sound insulation of soundproofing mechanisms (sound transmission loss)> The soundproofing mechanisms including the soundproofing materials of the examples and comparative examples of the present invention were subjected to an intensity method in accordance with JIS A1441-1. Specifically, a test facility room with a reverberation chamber as the sound source room and a semi-anechoic chamber as the sound receiving room was used, and the sound transmission loss [dB] relative to the 1 / 3 octave center frequency [Hz] was determined by 1 / 3 octave band analysis. As will be described later, in Examples 1 and 2 and Comparative Examples 1 and 2, the soundproofing mechanisms were constructed by laminating the soundproofing material on a steel plate, while in Comparative Examples 3 to 6, the soundproofing mechanisms were constructed using only a single soundproofing material. In this specification, a configuration consisting only of soundproofing material is also considered to be a type of soundproofing mechanism including soundproofing material.

[0021] [Example 1] In Example 1 of the present invention, a soundproofing material 1 was produced by the following steps. A polyether polyol to which additives and the like had been added in advance was mixed with toluene diisocyanate (TDI), a type of isocyanate, under conditions of an NCO index (equivalent ratio of hydroxyl groups to isocyanate groups) of 105. This mixture was foamed in a foaming box to obtain a polyurethane foam. The polyurethane foam thus formed was sliced ​​to a thickness of 13 mm to form a polyurethane foam layer 2. Meanwhile, a 2 mm thick sheet made of ethylene propylene diene rubber (EPDM) was prepared as the elastomer layer 3. The polyurethane foam layer 2 and the elastomer layer 3 were overlapped and adhered to each other to produce the soundproofing material 1.

[0022] As shown in Table 1, the density of the polyurethane foam layer 2 in this example is 53 kg / cm 3 The storage shear modulus G' and loss tangent tanδ of this polyurethane foam layer 2 at a temperature of 25°C and a frequency of 1 Hz were 1.74 × 10 4 The storage shear modulus G' and loss tangent tanδ at a temperature of 25°C and a frequency of 100 Hz are 2.08 × 10 4 The storage shear modulus G' and loss tangent tanδ at a temperature of 25°C and a frequency of 500 Hz are 2.36 × 10 4 The storage shear modulus G' and loss tangent tanδ at a temperature of 25°C and a frequency of 1000 Hz are 2.51 × 10 4 The storage shear modulus G' and loss tangent tanδ at a temperature of 25°C and a frequency of 2000 Hz are 3.24 x 10 4 The flow resistance per unit thickness of the polyurethane foam layer 2 was 2.09 × 10 4 Ns / m 4 The elastomer layer 3 of this example had a durometer A hardness of 60 and a density of 1260 kg / m 3 The surface density of this soundproofing material 1 (surface density before being attached to the steel plate, as will be described later) was 3.2 kg / cm 2 It was.

[0023] [Table 1]

[0024] This soundproofing material 1 was attached to a 0.8 mm thick iron plate 5 (for convenience, this iron plate is given the same reference numeral 5 as the steel plate in FIG. 1 ) which was used as an equivalent to the steel plate 5, an example of a vehicle panel, to form the soundproofing mechanism of this example. At this time, the soundproofing material 1 was placed so that the polyurethane foam layer 2 side was in contact with the iron plate 5. The sound transmission loss of the soundproofing mechanism consisting of this soundproofing material 1 and the iron plate 5 was calculated and the results are shown in Table 1. That is, the sound transmission loss for sound having a 1 / 3 octave center frequency of 500 Hz was 26.6 dB, the sound transmission loss for sound having a 1 / 3 octave center frequency of 630 Hz was 34.1 dB, the sound transmission loss for sound having a 1 / 3 octave center frequency of 800 Hz was 38.6 dB, the sound transmission loss for sound having a 1 / 3 octave center frequency of 1000 Hz was 42.4 dB, the sound transmission loss for sound having a 1 / 3 octave center frequency of 1250 Hz was 48.1 dB, the sound transmission loss for sound having a 1 / 3 octave center frequency of 1600 Hz was 50.6 dB, the sound transmission loss for sound having a 1 / 3 octave center frequency of 2000 Hz was 52.7 dB, and the sound transmission loss for sound having a 1 / 3 octave center frequency of 2500 Hz was 57.1 dB. The soundproofing mechanism of this embodiment provides high sound insulation (sound transmission loss). The soundproofing effect of the soundproofing mechanism of this embodiment increases as the 1 / 3 octave center frequency increases, and the soundproofing effect is particularly good against sounds with 1 / 3 octave center frequencies of 630 Hz or higher.

[0025] [Example 2] In Example 2 of the present invention, a polyether polyol to which an auxiliary agent or the like had been added in advance and a modified diphenylmethane diisocyanate (modified MDI), a type of isocyanate, were mixed under the condition of an NCO index of 70. This mixture was foamed on an EPDM sheet (elastomer layer 3) having a thickness of 2 mm set in a mold to form a polyurethane foam layer 2, thereby producing a soundproofing material 1.

[0026] The polyurethane foam layer 2 in this example has a thickness of 13 mm and a density of 55 kg / cm 3 The storage shear modulus G' and loss tangent tanδ of this polyurethane foam layer 2 at a temperature of 25°C and a frequency of 1 Hz were 7.57 × 10 3 The storage shear modulus G' and loss tangent tanδ at a temperature of 25°C and a frequency of 100 Hz are 1.16 × 10 4 The storage shear modulus G' and loss tangent tanδ at a temperature of 25°C and a frequency of 500 Hz are 1.39 × 10 4 The storage shear modulus G' and loss tangent tanδ at a temperature of 25°C and a frequency of 1000 Hz are 1.54 × 10 4 The storage shear modulus G' and loss tangent tanδ at a temperature of 25°C and a frequency of 2000 Hz are 1.62 × 10 4 The flow resistance per unit thickness of the polyurethane foam layer 2 was 5.93 x 10 4 Ns / m 4 The elastomer layer 3 of this example had the same structure as the elastomer layer 3 of Example 1, and had a durometer A hardness of 60 and a density of 1260 kg / m 3 The surface density of this soundproofing material 1 (surface density before being attached to the steel plate) was 3.2 kg / cm 2 It was.

[0027] This two-layered soundproofing material 1 was attached to a 0.8 mm thick steel plate 5 (corresponding to a steel plate 5, which is an example of a vehicle panel) so that the polyurethane foam layer 2 side was in contact with the steel plate 5, thereby forming the soundproofing mechanism of this example. The sound transmission loss of this soundproofing mechanism was measured and the results are shown in Table 1. That is, the sound transmission loss for sound having a 1 / 3 octave center frequency of 500 Hz was 24.3 dB, the sound transmission loss for sound having a 1 / 3 octave center frequency of 630 Hz was 34.0 dB, the sound transmission loss for sound having a 1 / 3 octave center frequency of 800 Hz was 37.8 dB, the sound transmission loss for sound having a 1 / 3 octave center frequency of 1000 Hz was 42.1 dB, the sound transmission loss for sound having a 1 / 3 octave center frequency of 1250 Hz was 48.9 dB, the sound transmission loss for sound having a 1 / 3 octave center frequency of 1600 Hz was 53.5 dB, the sound transmission loss for sound having a 1 / 3 octave center frequency of 2000 Hz was 58.0 dB, and the sound transmission loss for sound having a 1 / 3 octave center frequency of 2500 Hz was 62.2 dB. As in Example 1, the soundproofing mechanism of this example also provides high sound insulation (sound transmission loss), and the sound insulation is particularly good against sounds with 1 / 3 octave center frequencies of 630 Hz or higher.

[0028] [Comparative Example 1] In Comparative Example 1 for comparison with the present invention, a polyether polyol to which an auxiliary agent or the like had been added in advance and TDI, a type of isocyanate, were mixed under the condition of an NCO index of 100. This mixture was foamed on an EPDM sheet (elastomer layer 3) having a thickness of 2 mm set in a mold to form a polyurethane foam layer 2, thereby producing a soundproofing material 1.

[0029] The polyurethane foam layer 2 of this comparative example has a thickness of 13 mm and a density of 65 kg / cm 3 The storage shear modulus G' and loss tangent tanδ of this polyurethane foam layer 2 at a temperature of 25°C and a frequency of 1 Hz were 1.81 × 10 5The storage shear modulus G' and loss tangent tanδ at a temperature of 25°C and a frequency of 100 Hz are 2.62 × 10 5 The storage shear modulus G' and loss tangent tanδ at a temperature of 25°C and a frequency of 500 Hz are 2.98 × 10 5 The storage shear modulus G' and loss tangent tanδ at a temperature of 25°C and a frequency of 1000 Hz are 3.23 × 10 5 The storage shear modulus G' and loss tangent tanδ at a temperature of 25°C and a frequency of 2000 Hz are 3.36 × 10 5 The flow resistance per unit thickness of the polyurethane foam layer 2 was 3.62 × 10 4 Ns / m 4 The elastomer layer 3 of this comparative example had the same structure as the elastomer layer 3 of Examples 1 and 2, and had a durometer A hardness of 60 and a density of 1260 kg / m 3 The surface density of this soundproofing material 1 (surface density before attachment to the steel plate) was 3.3 kg / cm 2 It was.

[0030] This two-layered soundproofing material 1 was attached to a 0.8 mm thick steel plate 5 (corresponding to a steel plate 5, which is an example of a vehicle panel) with the polyurethane foam layer 2 side in contact with the steel plate 5, thereby forming a soundproofing mechanism of this comparative example. The sound transmission loss of this soundproofing mechanism was measured and the results are shown in Table 1. That is, the sound transmission loss for sound having a 1 / 3 octave center frequency of 500 Hz was 27.7 dB, the sound transmission loss for sound having a 1 / 3 octave center frequency of 630 Hz was 27.7 dB, the sound transmission loss for sound having a 1 / 3 octave center frequency of 800 Hz was 27.3 dB, the sound transmission loss for sound having a 1 / 3 octave center frequency of 1000 Hz was 25.7 dB, the sound transmission loss for sound having a 1 / 3 octave center frequency of 1250 Hz was 32.3 dB, the sound transmission loss for sound having a 1 / 3 octave center frequency of 1600 Hz was 40.6 dB, the sound transmission loss for sound having a 1 / 3 octave center frequency of 2000 Hz was 49.7 dB, and the sound transmission loss for sound having a 1 / 3 octave center frequency of 2500 Hz was 54.1 dB. The soundproofing mechanism of this comparative example does not have sufficient sound insulation (sound transmission loss), and is particularly inferior to Examples 1 and 2 in sound insulation against sounds with 1 / 3 octave center frequencies of 630 Hz or higher.

[0031] Comparative Example 2 In Comparative Example 2, a polyether polyol containing additives and the like was mixed with modified MDI, a type of isocyanate, under conditions of an NCO index of 80. This mixture was foamed in a foaming box to obtain a polyurethane foam. The polyurethane foam thus formed was sliced ​​to a thickness of 13 mm to form a polyurethane foam layer 2. This was then superimposed on and bonded to an elastomer layer 3 made of a 2 mm thick EPDM sheet, thereby producing a soundproofing material 1.

[0032] The polyurethane foam layer 2 of this comparative example has a thickness of 13 mm and a density of 54 kg / cm 3 The storage shear modulus G' and loss tangent tanδ of this polyurethane foam layer 2 at a temperature of 25°C and a frequency of 1 Hz were 1.49 × 104 The storage shear modulus G' and loss tangent tanδ at a temperature of 25°C and a frequency of 100 Hz are 6.08×10 4 The storage shear modulus G' and loss tangent tanδ at a temperature of 25°C and a frequency of 500 Hz are 8.69 × 10 4 The storage shear modulus G' and loss tangent tanδ at a temperature of 25°C and a frequency of 1000 Hz are 1.00 × 10 5 The storage shear modulus G' and loss tangent tanδ at a temperature of 25°C and a frequency of 2000 Hz are 1.21 × 10 5 The flow resistance per unit thickness of the polyurethane foam layer 2 was 5.22 x 10 4 Ns / m 4 The elastomer layer 3 of this comparative example had the same structure as the elastomer layer 3 of Examples 1 and 2, and had a durometer A hardness of 60 and a density of 1260 kg / m 3 The surface density of this soundproofing material 1 (surface density before attachment to the steel plate) was 3.2 kg / cm 2 It was.

[0033] This two-layered soundproofing material 1 was attached to a 0.8 mm thick steel plate 5 (corresponding to a steel plate 5, which is an example of a vehicle panel) with the polyurethane foam layer 2 side in contact with the steel plate 5, thereby forming a soundproofing mechanism of this comparative example. The sound transmission loss of this soundproofing mechanism was measured and the results are shown in Table 1. That is, the sound transmission loss for sound having a 1 / 3 octave center frequency of 500 Hz was 25.5 dB, the sound transmission loss for sound having a 1 / 3 octave center frequency of 630 Hz was 29.2 dB, the sound transmission loss for sound having a 1 / 3 octave center frequency of 800 Hz was 29.8 dB, the sound transmission loss for sound having a 1 / 3 octave center frequency of 1000 Hz was 31.0 dB, the sound transmission loss for sound having a 1 / 3 octave center frequency of 1250 Hz was 36.8 dB, the sound transmission loss for sound having a 1 / 3 octave center frequency of 1600 Hz was 42.7 dB, the sound transmission loss for sound having a 1 / 3 octave center frequency of 2000 Hz was 48.2 dB, and the sound transmission loss for sound having a 1 / 3 octave center frequency of 2500 Hz was 53.9 dB. As with Comparative Example 1, the soundproofing mechanism of this Comparative Example also does not have sufficient sound insulation (sound transmission loss), and is particularly inferior to Examples 1 and 2 in sound insulation against sounds with 1 / 3 octave center frequencies of 630 Hz or higher.

[0034] Comparative Example 3 In Comparative Example 3, the same soundproofing material 1 as in Example 1 was manufactured, and this soundproofing material 1 was used alone without being attached to an iron plate 5. In other words, the soundproofing material 1 itself constitutes the soundproofing mechanism. The properties of the polyurethane foam layer 2 and elastomer layer 3 of this Comparative Example are the same as those of the polyurethane foam layer 2 and elastomer layer 3 of Example 1. The surface density of the soundproofing material 1 is 3.2 kg / cm 2The sound transmission loss of this soundproofing mechanism was calculated and the results are shown in Table 1. That is, the sound transmission loss for sound having a 1 / 3 octave center frequency of 500 Hz was 18.6 dB, the sound transmission loss for sound having a 1 / 3 octave center frequency of 630 Hz was 21.7 dB, the sound transmission loss for sound having a 1 / 3 octave center frequency of 800 Hz was 21.3 dB, the sound transmission loss for sound having a 1 / 3 octave center frequency of 1000 Hz was 21.3 dB, the sound transmission loss for sound having a 1 / 3 octave center frequency of 1250 Hz was 23.7 dB, the sound transmission loss for sound having a 1 / 3 octave center frequency of 1600 Hz was 24.0 dB, the sound transmission loss for sound having a 1 / 3 octave center frequency of 2000 Hz was 22.9 dB, and the sound transmission loss for sound having a 1 / 3 octave center frequency of 2500 Hz was 27.4 dB. The soundproofing mechanism of this comparative example has clearly lower sound insulation (sound transmission loss) than the soundproofing mechanisms of Examples 1 and 2, and is also lower in sound insulation than the soundproofing mechanisms of Comparative Examples 1 and 2.

[0035] Comparative Example 4 In Comparative Example 4, the same soundproofing material 1 as in Example 2 was manufactured, and this soundproofing material 1 was used alone without being attached to an iron plate 5. In other words, the soundproofing material 1 itself constitutes the soundproofing mechanism. The properties of the polyurethane foam layer 2 and elastomer layer 3 of this Comparative Example are the same as those of the polyurethane foam layer 2 and elastomer layer 3 of Example 2. The surface density of the soundproofing material 1 is 3.2 kg / cm 2The sound transmission loss of this soundproofing mechanism was calculated and the results are shown in Table 1. That is, the sound transmission loss for sound having a 1 / 3 octave center frequency of 500 Hz was 16.0 dB, the sound transmission loss for sound having a 1 / 3 octave center frequency of 630 Hz was 18.1 dB, the sound transmission loss for sound having a 1 / 3 octave center frequency of 800 Hz was 17.5 dB, the sound transmission loss for sound having a 1 / 3 octave center frequency of 1000 Hz was 17.5 dB, the sound transmission loss for sound having a 1 / 3 octave center frequency of 1250 Hz was 20.4 dB, the sound transmission loss for sound having a 1 / 3 octave center frequency of 1600 Hz was 23.3 dB, the sound transmission loss for sound having a 1 / 3 octave center frequency of 2000 Hz was 25.1 dB, and the sound transmission loss for sound having a 1 / 3 octave center frequency of 2500 Hz was 29.9 dB. The soundproofing mechanism of this comparative example has clearly lower sound insulation (sound transmission loss) than the soundproofing mechanisms of Examples 1 and 2, and is also lower in sound insulation than the soundproofing mechanisms of Comparative Examples 1 and 2.

[0036] Comparative Example 5 In Comparative Example 5, the same soundproofing material 1 as in Comparative Example 1 was manufactured, and this soundproofing material 1 was used alone without being attached to an iron plate 5. In other words, the soundproofing material 1 itself constitutes the soundproofing mechanism. The properties of the polyurethane foam layer 2 and elastomer layer 3 of this Comparative Example are the same as those of the polyurethane foam layer 2 and elastomer layer 3 of Comparative Example 1. The surface density of the soundproofing material 1 was 3.3 kg / cm. 2The sound transmission loss of this soundproofing mechanism was calculated and the results are shown in Table 1. That is, the sound transmission loss for sound having a 1 / 3 octave center frequency of 500 Hz was 18.1 dB, the sound transmission loss for sound having a 1 / 3 octave center frequency of 630 Hz was 21.5 dB, the sound transmission loss for sound having a 1 / 3 octave center frequency of 800 Hz was 21.6 dB, the sound transmission loss for sound having a 1 / 3 octave center frequency of 1000 Hz was 22.7 dB, the sound transmission loss for sound having a 1 / 3 octave center frequency of 1250 Hz was 27.1 dB, the sound transmission loss for sound having a 1 / 3 octave center frequency of 1600 Hz was 30.9 dB, the sound transmission loss for sound having a 1 / 3 octave center frequency of 2000 Hz was 31.9 dB, and the sound transmission loss for sound having a 1 / 3 octave center frequency of 2500 Hz was 29.3 dB. The soundproofing mechanism of this comparative example has clearly lower sound insulation (sound transmission loss) than the soundproofing mechanisms of Examples 1 and 2, and is also lower in sound insulation than the soundproofing mechanisms of Comparative Examples 1 and 2.

[0037] Comparative Example 6 In Comparative Example 6, the same soundproofing material 1 as in Comparative Example 2 was manufactured, and this soundproofing material 1 was used alone without being attached to an iron plate 5. In other words, the soundproofing material 1 itself constitutes the soundproofing mechanism. The properties of the polyurethane foam layer 2 and elastomer layer 3 of this Comparative Example are the same as those of the polyurethane foam layer 2 and elastomer layer 3 of Comparative Example 2. The surface density of the soundproofing material 1 was 3.2 kg / cm. 2The sound transmission loss of this soundproofing mechanism was calculated and the results are shown in Table 1. That is, the sound transmission loss for sound having a 1 / 3 octave center frequency of 500 Hz was 18.4 dB, the sound transmission loss for sound having a 1 / 3 octave center frequency of 630 Hz was 21.1 dB, the sound transmission loss for sound having a 1 / 3 octave center frequency of 800 Hz was 20.9 dB, the sound transmission loss for sound having a 1 / 3 octave center frequency of 1000 Hz was 21.1 dB, the sound transmission loss for sound having a 1 / 3 octave center frequency of 1250 Hz was 24.9 dB, the sound transmission loss for sound having a 1 / 3 octave center frequency of 1600 Hz was 28.6 dB, the sound transmission loss for sound having a 1 / 3 octave center frequency of 2000 Hz was 30.0 dB, and the sound transmission loss for sound having a 1 / 3 octave center frequency of 2500 Hz was 33.8 dB. The soundproofing mechanism of this comparative example has clearly poorer sound insulation than the soundproofing mechanisms of Examples 1 and 2, and also has poorer sound insulation than the soundproofing mechanisms of Comparative Examples 1 and 2.

[0038] Comparative Example 7 The sound transmission loss of only a 0.8 mm thick iron plate 5, which is an example of a vehicle panel and corresponds to a steel plate 5, is shown in Table 1. In this comparative example, only an iron plate 5 corresponding to a vehicle panel is present, and no soundproofing material consisting of a polyurethane foam layer and an elastomer layer is present, so the sound insulation is clearly inferior.

[0039] [Sound insulation (sound transmission loss) in Examples and Comparative Examples] As explained above, Examples 1 and 2 of the present invention provide good sound insulation (sound transmission loss). In particular, the soundproofing mechanisms of Examples 1 and 2 generally provide good sound insulation against low-frequency sounds (road noise, tire noise, etc.) that have become a problem in recent automobiles, specifically sounds in a wide frequency range from 500 Hz to 1250 Hz. That is, for sounds with a frequency of 500 Hz, Examples 1 and 2 and Comparative Examples 1 and 2 provide approximately the same level of sound insulation, and for sounds with higher frequencies, Examples 1 and 2 provide better sound insulation than Comparative Examples 1 and 2. Furthermore, the soundproofing material 1 of the soundproofing mechanisms of Examples 1 and 2 has a low surface density, is lightweight, and is thin. Thus, since the soundproofing mechanisms of Examples 1 and 2 have better sound insulation than the soundproofing mechanisms of Comparative Examples 1 and 2, the storage shear modulus G' of the polyurethane foam layer 2 at a temperature of 25°C and a frequency of 1 Hz to 2000 Hz is 5.0 × 10 3 Pa or more and 1.0×10 5 It can be said that it is preferable that the polyurethane foam layer 2 has a storage shear modulus G' of 7.5×10 Pa or less at a temperature of 25° C. and a loss tangent tanδ of 0.01 or more and 0.3 or less at a frequency of 1 Hz to 2000 Hz. 3 Pa or more and 3.5×10 4 It is more preferable that the storage shear modulus G' of the polyurethane foam layer 2 at a temperature of 25°C and a frequency of 1 Hz to 2000 Hz is 1.0 × 10 Pa or less, and the loss tangent tanδ is 0.09 or more and 0.3 or less. 5 Pa or less, preferably 3.5×10 4 When the soundproofing material 1 has a shear storage modulus G' of 5.0 x 10 Pa or less at a temperature of 25°C and a frequency of 1 Hz to 2000 Hz, the soundproofing material 1 can be easily assembled to a vehicle body and provides a good feeling of stepping on when used as a floor carpet, for example. 3 Pa or more, preferably 7.5 × 10 3 If the strength is 100 Pa or more, it is resistant to deformation caused by being stepped on or having items placed on it.

[0040] The flow resistance per unit thickness of the polyurethane foam layer 2 is 1.0 × 10 4 Ns / m 4 If it is above 1.0×10, the sound absorption performance is good across the entire frequency range. 6 Ns / m 4 A value below this range is preferable because it provides good sound absorption characteristics, particularly for sounds with frequencies of 1000 Hz or higher. When the soundproofing material 1 is actually used, the polyurethane foam layer 2 may be exposed at the sides (edges), and when sound waves enter from these sides or gaps, the sound absorption function of the polyurethane foam layer 2 itself may be required. In order to achieve sound absorption function for sounds in the frequency range for which sound insulation is currently particularly desired, it is preferable that the flow resistance per unit thickness of the polyurethane foam layer 2 be within the above-mentioned range.

[0041] The density of the polyurethane foam layer 2 is 40 kg / m 3 More than 80kg / m 3 The density of the elastomer layer is preferably 1000 kg / m or less. 3 More than 2000kg / m 3 The density of the polyurethane foam layer 2 is preferably 40 kg / m or less. 3 or more, and the density of the elastomer layer 3 is 1000 kg / m 3 When the density of the polyurethane foam layer 2 is 80 kg / m or more, the polyurethane foam layer 2 has good filling properties (fluidity) even when the polyurethane foam layer 2 is thin. 3 and the density of the elastomer layer 3 is 2000 kg / m or less. 3 If the thickness is less than this, the soundproofing material 1 can be made lightweight.

[0042] The elastomer layer 3 preferably has a durometer A hardness of 20 or more and 80 or less. When the durometer A hardness of the elastomer layer 3 is 80 or less, the soundproofing material 1 can be suitably assembled to conform to the contours of an actual vehicle body having irregularities, and the soundproofing material 1 provides a comfortable feel when used, for example, as a floor carpet. Furthermore, when the durometer A hardness of the elastomer layer 3 is 20 or more, the soundproofing material 1 is resistant to deformation caused by being stepped on or having objects placed on it.

[0043] As described above, the properties of the polyurethane foam layer 2 (e.g., storage shear modulus G', loss tangent tanδ, unit thickness flow resistance, density) can be set within preferred ranges by adjusting the molecular structure of the polyol (e.g., structural units, number of functional groups, hydroxyl value, molecular weight), the molecular structure of the isocyanate (e.g., structural units, number of functional groups, NCO %, molecular weight), NCO index, foaming conditions (e.g., liquid temperature, stirring speed, stirring time, mold temperature), and the types and amounts of various auxiliaries (e.g., blowing agents, foam stabilizers, catalysts, crosslinking agents). The properties of the elastomer layer 3 (e.g., durometer A hardness and density) can be set within preferred ranges by adjusting the molecular skeleton of the polymer constituting the elastomer layer 3 (e.g., structural units, molecular weight, molecular weight distribution, branched structure), the type and amount of crosslinking (vulcanization) agent, the type and amount of additives, and the degree of crosslinking (vulcanization) by adjusting the crosslinking (vulcanization) conditions.

[0044] The soundproofing mechanism of the present invention can provide sufficient sound insulation while maintaining a spacious interior space with a thickness (18 mm or less) equivalent to or less than that of floor carpet, a conventional soundproofing material. In this case, to obtain good sound insulation, it is preferable that the thickness of the polyurethane foam layer 2 is 15 mm or less and the thickness of the elastomer layer 3 is 3 mm or less.

[0045] The soundproofing mechanisms of Examples 1 and 2 exhibit significantly better sound insulation than the steel plate 5 of Comparative Example 7 and the soundproofing mechanisms of Comparative Examples 3 to 6. This shows that a soundproofing mechanism constructed by laminating the soundproofing material 1 of the present invention onto a vehicle panel (for example, the steel plate 5 of the floor part A of an automobile 4) exhibits particularly good sound insulation. A soundproofing mechanism including the soundproofing material 1 of the present invention, which has these technical advantages, is very suitable as a soundproofing mechanism for an automobile.

[0046] As an example, it is preferable that the thickness of the vehicle panel (e.g., steel plate 5) to which the soundproofing material of the present invention is attached is about 0.8 mm, the thickness of the polyurethane foam layer 2 is 15 mm or less, the thickness of the elastomer layer 3 is 3 mm or less, and the overall thickness of the soundproofing material 1 is 18 mm or less. The density of the elastomer layer 3 is 1000 kg / m3 ~2000kg / m 3 It is preferable that the vehicle panel be made of other materials (aluminum, FRP, CFRP) instead of the steel plate 5. The vehicle panel made of the steel plate 5 or other materials may have a vibration-damping material, such as an asphalt sheet or paint, attached or applied thereto. [Explanation of symbols]

[0047] 1. Soundproofing material 2 polyurethane foam layers 3 Elastomer layer 4. Automobiles 5. Steel plates (vehicle panels, steel plates)

Claims

1. The soundproofing material for automobiles has a two-layer structure in which a polyurethane foam layer and an elastomer layer are laminated, and a vehicle panel that constitutes a part of the body of the automobile, the polyurethane foam layer of the soundproofing material has a storage shear modulus G' of 7.57 x 10 3 Pa or more and 3.24 x 10 4 Pa ​​or less at a temperature of 25°C and a frequency of 1 Hz to 2000 Hz, a loss tangent tanδ of 0.09 or more and 0.27 or less at a temperature of 25°C and a frequency of 1 Hz to 2000 Hz, a flow resistance per unit thickness of 2.09 x 10 4 Ns / m 4 or more and 5.93 x 10 4 Ns / m 4 or less, and a density of 53 kg / m 3 or more and 55 kg / m 3 or less; The soundproofing mechanism, wherein the soundproofing material is laminated to the vehicle panel.

2. 2. The soundproofing mechanism according to claim 1, wherein the soundproofing material is laminated to the vehicle panel so that the polyurethane foam layer contacts the vehicle panel.

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