JP2007030268A - Sound absorbing/cutting-off material - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a sound absorbing/cutting-off material having excellent low temperature execution properties and excellent in sound absorbing properties and sound barrier properties in a low-medium frequency region. <P>SOLUTION: A resin layer, which has air permeability 1/2-1/50 that of a foamable resin base material having continuous air permeability, or a resin layer, which comprises a resin film having perforated parts, is provided on the surface of the foamable resin base material. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a sound absorbing and insulating material, and more particularly to a sound absorbing and insulating material having excellent sound insulating properties and sound absorbing properties, which is used in construction machines, automobile engine rooms, and the like.

  There is a strong demand for sound-absorbing materials used in construction machinery, automobile engine rooms, and the like to improve sound absorption in the low to medium frequency range. Furthermore, in order to improve the sound absorption, such a sound absorbing material will have air permeability, but when the water enters the sound absorbing material due to rain or water washing, the sound absorbing property is deteriorated, and the sound absorbing material is rapidly deteriorated, There is a problem that durability is lowered. However, if the surface is covered with a non-breathable material, there is a concern that the sound absorbing material may be deteriorated due to reflection of an incoming sound wave.

As a method for improving sound absorption in the low to medium frequency range, a technique for improving sound absorption by laminating a plastic film imparted with air permeability on a normal flexible urethane foam has been proposed (see, for example, Patent Document 1). .) However, when a known flexible urethane foam is used, sufficient air permeability cannot be obtained, and there is still room for improvement from the viewpoint of vibration attenuation due to sound wave approach.
In response, the applicant of the present application has proposed a flame-retardant sound-absorbing material in which a polyester film or a polyethylene film is laminated and melt-bonded to one side of a flame-retardant flexible urethane foam having a specific thickness to control the overall breathability. (For example, refer to Patent Document 2). This sound-absorbing material is excellent in waterproofness, flame retardancy, and sound-absorbing property, but requires further fusion bonding between raw material sheets at the time of manufacture, and therefore further improvement is desired from the viewpoint of low-temperature workability. The current situation is.
JP-A-61-53035 JP-A-10-119219

  An object of the present invention made in consideration of the above problems is to provide a sound absorbing and insulating material excellent in low-temperature workability, high sound absorbing property and sound insulating property in a low to medium frequency range.

The inventors of the present invention have focused on the air permeability of a laminated sound absorbing and insulating material composed of a urethane foam and a resin layer, and as a result of intensive studies, the above object has been achieved by controlling the air permeability of both under predetermined conditions. As a result, the present invention has been completed.
That is, the configuration of the present invention is as follows.
<1> A sound absorbing and insulating material having a resin layer having a breathability of 1/2 to 1/50 of the foamed resin substrate on the surface of the foamable resin substrate having continuous breathability.
<2> A sound-absorbing and insulating material having a resin layer made of a resin film in which an aperture is formed on the surface of a foamable resin base material having continuous air permeability.
<3> The sound absorbing and insulating material according to <2>, wherein an opening diameter of the resin film formed with the opening is 10 to 500 μm.

<4> The sound absorbing and insulating material according to <1> or <2>, wherein the resin layer is made of a locally thinned resin film.
<5> The sound absorbing and insulating material according to <1> or <2>, wherein the resin layer is made of a polyurethane film.
<6> The air permeability of the foamable resin substrate is in the range of ³ to 100 ml / cm ² · sec, and the air permeability of the resin layer is in the range of 0.06 to 50 ml / cm ² · sec. The sound absorbing and insulating material according to any one of <1> to <5>.
<7> The sound absorbing and insulating material according to any one of <1> to <6>, further including a resin nonwoven fabric layer on the surface of the resin layer.

  ADVANTAGE OF THE INVENTION According to this invention, the sound-absorbing / insulating material excellent in low temperature construction property, the high sound-absorbing property in the low-medium frequency range, and the sound-insulating property can be provided.

The present invention is described in detail below.
The sound-absorbing and insulating material of the present invention forms a resin layer or an opening having a breathability of 1/2 to 1/50 of the foamed resin base material on the surface of the foamable resin base material having continuous breathability. It has a laminated structure that is formed by laminating a resin layer made of a resin film, and if desired, a resin nonwoven fabric layer may be further provided on the surface of the resin layer.
Hereinafter, each layer will be described.

(Foamed resin base material with continuous air permeability)
The foamable resin substrate used in the present invention is a resin substrate containing bubbles, and has continuous air permeability. Examples of such a foamable resin base material include a sheet made of a foamable resin having open cells, and is excellent in the internal attenuation characteristics of energy, so that it is useful for effective attenuation and blocking of sound waves. .

As the foamable resin base material, a sheet-like base material made of a resin such as a polyether-based urethane foam and a polyester-based urethane foam is preferable, and among them, a polyether-based urethane foam is preferable from the viewpoint of damping characteristics.
Specifically, it is not particularly limited as long as it is a flexible urethane foam that meets UL-94, HF-1, MVSS302, blank inspection, AA standards, etc., but, for example, Everlite VHZ, VP, VD (trade name, manufactured by Pridestone) And the like.
The thickness of such a foamable resin base material can be appropriately selected depending on the intended sound absorbing and insulating effect, the place where the foamed resin base material is disposed, etc., but is generally in the range of 10 to 100 mm, preferably 10 to 50 mm. .

In the present invention, breathability of the foamable resin substrate to be used in吸遮sound material is preferably from 3~100ml / cm ² · sec, more preferably from the viewpoint of the effect 5~50ml / cm ² · sec is there. Excellent sound absorbing performance is obtained in this range of air permeability. In addition, the value measured according to JISL1096A method is used for the air permeability in this invention.

(Resin layer having breathability of 1/2 to 1/50 of the foamed resin base material)
In the first aspect of the sound absorbing and insulating material of the present invention, a resin layer having specific air permeability is provided on the surface of the foamed resin base material.
This resin layer is formed in close contact with the surface of the foamed resin base material without being peeled off. In general, it is preferable that the resin layer be laminated on the surface of the foamed resin base material by melting and bonding.
As the resin layer, resin films such as polyester, polyethylene, polyamide, and polyether are used, and specific materials include hot melt films such as EVA, modified EVA, polyethylene, polypropylene, polyester, polyamide, and polyurethane. It is done.

Among these, a polyurethane film having a high melting point and a low Tg is preferable from the viewpoint of low-temperature workability.
The lower the melting point of the film constituting the resin layer, the better the workability is because it can be melted at a low temperature. On the other hand, from the viewpoint of product performance, when the operating temperature is high, the film is likely to melt or peel off, causing problems. From that point of view, it is better that the melting point is higher. Further, from the viewpoint of low temperature workability, those having a low glass transition temperature (Tg), specifically those having a temperature of 0 ° C. or lower, are preferable because they can be bonded at a low temperature.
By using a resin layer that can be heat-sealed with a foamed resin base material without using a hot melt adhesive in this way, the process can be reduced and economically preferable, and such a material is used. There is no decrease in waterproofness or sound absorption due to the operation.

  The thickness of the resin layer used in the present invention is 20 to 50 μm, and preferably 30 to 40 μm from the viewpoint of effects. If this thickness is too thin, there is a concern that sufficient adhesion with the foamed resin base material cannot be obtained and the function as a surface layer cannot be sufficiently exhibited, and if it is too thick, the sound absorption characteristics tend to be reduced due to reflection of incoming sound waves. There is.

The air permeability of the resin layer needs to be 1/2 to 1/5 of the foamed resin base material. The preferable air permeability of the resin layer is preferably in the range of 5 to 50 ml / cm ² · sec in absolute amount, and in the range of ^1/2 to 1/50 of the air permeability of the foamed resin base material to be laminated, in other words. For example, those having an air flow rate of 2 to 50% of the air flow rate of the foamable resin base material are used, preferably in the range of 1/3 to 1/20.
This resin layer is a film that adheres to the surface of the foamable resin base material, and its action is not clear, but by increasing the energy attenuation characteristics due to membrane vibration on the sheet surface made of foamable resin with continuous air permeability, It is thought to improve the sound absorption and insulation effect on the water.

  Examples of a method for imparting air permeability to the resin layer include a method of forming a thin region locally by embossing a resin film in addition to a method of providing an opening in a film constituting the resin layer. When a resin film having such a thin region is laminated on a foamable resin substrate and thermocompression bonded, the thin portion is melted to form an appropriate aperture. The thinnest area of the thinned region is preferably in the range of 10 to 500 μm in diameter, and the thickness is preferably about 0 to 10 μm. Examples of the method for forming the local thin portion include a compression method using an emboss roll.

Further, the second aspect of the present invention is characterized in that a resin film having a fine opening is provided on the surface of the foamed resin base material as a resin layer having excellent air permeability. Thus, according to the method of providing the opening in the resin film, there is an advantage that the air permeability of the resin layer can be easily controlled. It is preferable that the diameter of the aperture (the long diameter when not a perfect circle) is in the range of 10 to 500 μm, and more preferably in the range of 100 to 200 μm. The hole density is preferably 5 to 50 holes / cm ² , and desired air permeability can be achieved by controlling the hole diameter and the hole density according to the purpose. If the aperture diameter is too small, the incident sound wave may be reflected. If it is too large, it becomes difficult to keep the difference in air permeability from the foamable resin base material within the above range.
There is no particular limitation on the method for forming the aperture in the resin film, and for example, a known resin film perforation method such as a laser melting aperture method or a needle punch method can be applied.
According to this method, the hole diameter and the hole density can be easily set to desired conditions, and the air permeability can be easily controlled as described above.

  When the resin layer is formed on the surface of the foamable resin base material in the present invention by thermocompression bonding, an opening portion may be formed by melting of the resin layer depending on temperature conditions. However, it goes without saying that it is extremely difficult to achieve the desired air permeability defined in the present invention by forming the opening due to such non-uniform manufacturing.

(Resin nonwoven layer)
In the sound-absorbing and insulating material of the present invention, when a high tear resistance is required for the melt-bonded resin layer depending on the purpose of use, the air permeability on the resin layer surface should be 5 ml / cm ² · sec or more. A flexible resin nonwoven fabric layer can be provided. Due to the presence of the nonwoven fabric layer, tear resistance can be greatly improved without impairing the properties of the sound absorbing and insulating material.

The resin nonwoven fabric that can be used in the present invention is not particularly limited as long as it has air permeability of 5 ml / cm ² · sec or more and has flexibility. In this case, for example, it is preferable to use one having air permeability of 80 ml / cm ² · sec or more.
The resin nonwoven fabric is preferably a nonwoven fabric using fibers made of a resin such as polyester, polyamide, and polypropylene. Specifically, for example, a nylon nonwoven fabric (weight per unit area: 20 g / m ² , air permeability: 400 ml / cm ² · second) And the like), nylon nonwoven fabric (weight per unit area: 30 g / m ² , air permeability: 400 ml / cm ² · sec or more), and the like.

Among the above-mentioned resin nonwoven fabrics, fine ones (thickness of constituent fibers, large basis weight, small air permeability) increase the tear resistance (reinforcing property) of the film. Tear resistance is not required, it is expensive, and it is disadvantageous from the viewpoint that the air permeability of the sound absorbing and insulating material is reduced. On the other hand, it is rough (the thickness of the component sane committee is small, the basis weight is small) The material having a high air permeability is advantageous from the viewpoint that the tear resistance can satisfy the required characteristics in the present invention, is inexpensive, and further the air permeability of the sound absorbing and insulating material is increased. From this viewpoint, among the above examples, nylon nonwoven fabric (weight per unit area: about 20 g / cm ² ) is preferably used.

(Manufacture of sound absorbing and insulating materials)
The sound absorbing and insulating material manufacturing method of the present invention may take any method as long as the sound absorbing and insulating material is laminated with the specific foamable resin base material and the resin layer as described above and satisfies the specific air permeability condition. However, the surface of the laminate when, for example, thermocompression bonding of a breathable urethane foam sheet (foamable resin base material) and a polyester film (resin layer) having a specific opening without a hot melt adhesive is used. A release paper is laminated on the top, and heated with a heating plate from above, for example, at 125 ° C. or higher, and the foamable resin base material and the resin layer are heat-sealed. After removing the sound absorbing and insulating material laminated with release paper from the board and cooling and solidifying at room temperature, it is possible to take the method of peeling the release paper. According to this method, the sound absorbing and insulating material has little energy loss, and Can be easily manufactured in a short time.

  Further, if necessary, a non-woven resin as a film reinforcing material is laminated on the resin layer, a release paper is laminated thereon, and a flame retardant sound absorbing and insulating sound having the film reinforcing material is obtained in the same manner as described above. The material can be manufactured. Further, when a fine resin nonwoven fabric is used here, the film does not often stick to the hot platen, and thus it is not always necessary to use a release paper.

  EXAMPLES Hereinafter, the present invention will be described more specifically with reference to examples. However, the present invention is not limited to the examples as long as the gist of the present invention is not exceeded.

Various measurements were performed by the following methods.
1. Measuring method of air permeability The thickness of each of the foamable resin base material and the resin layer constituting the sound absorbing and insulating material was used as a sample, and the air permeability was measured according to JIS L 1096A method.

2. Measuring method of sound absorption rate It measured by the reverberation room method sound absorption rate in frequency 200-5000Hz. The reverberation room method sound absorption coefficient α is calculated by the following equation.
α = (4 log _e 10 ⁶ / c) × V / S × (1 / T ₁ −1 / T ₀ )
(Where c: sound velocity, V: reverberation chamber volume = 9 m ³ , S: sample area = 1.2 m ² , T ₀ : vacant reverberation time, T ₁ : reverberation time)
There are two methods for measuring sound absorption: a method based on normal incidence method sound absorption measurement using an acoustic tube and a method based on reverberation chamber method sound absorption rate measurement performed in a reverberation room. Since the sound-absorbing and insulating material with a coating exhibits sound absorbing performance due to a resonance phenomenon, the sound absorption coefficient measurement using the reverberation chamber method is used because the sound absorption coefficient measurement is not accurate.

3. 1. Sound insulation property In a soundless room, a “normal incidence sound insulation rate measuring device” 10 as shown in FIG. 1 is prepared, and a sample 12 obtained by cutting the sound absorbing and insulating materials of Examples and Comparative Examples into 500 × 600 mm is set. The sound pressure of the sound generated from the four speakers 18 arranged in the sound insulation box 16 is measured by the microphone 14 located at a height of 200 mm. Thereafter, the same measurement is performed with the sample 12 removed, and the sound insulation is evaluated from the difference in sound pressure between the two.
In addition, the sound insulation cover was made into the double structure, the sound intensity measurement location was performed at six points, and the sound insulation cover and the sample were sealed with clay.

4). Low-temperature workability The sound-absorbing and insulating materials of Examples and Comparative Examples are used as samples, placed on a hard surface, and allowed to stand in an atmosphere of −10 ° C. for 24 hours. Thereafter, a weight of 500 mm and a weight of 500 g is dropped on the surface of the sample from a position of 500 mm in the atmosphere. The sample is visually observed for cracks. Evaluation is given as ◯ when 1 or less cracks occur and x when 2 or more cracks occur.

[Example 1]
On a heating plate below a press molding apparatus heated to 125 ° C. and provided with a lower heating plate, a density of 23 kg / m ³ , a hardness of 10 kgf, a thickness of 25 mm, and a breathability of 130 ml / cm ² · sec. A breathable urethane foam (VHZ, trade name, manufactured by Bridgestone Corporation) is placed thereon, and a polyurethane film (U1490, trade name, manufactured by Kurashiki Textile Co., Ltd.) having a thickness of 30 μm is formed thereon with 100 apertures of 300 μm in diameter / cm ^2. A resin layer with a permeability of 30 ml / cm ² · second is formed, and a release paper (SBK70J, trade name, manufactured by Lintec Corporation) is placed, and this is compressed by the upper heating plate at 125 ° C for 90 seconds. The sound absorbing and insulating material with release paper was removed from the heating platen by applying pressure and heating at a strain of 20%. After leaving to cool at room temperature, the release paper was peeled off to obtain the sound absorbing and insulating material of Example 1. Various properties (low temperature workability, sound insulation, sound absorption rate) of this sound absorbing and insulating material were measured, and the results are shown in Table 1.

[Comparative Example 1]
Instead of the polyurethane film resin layer having an aperture used in Example 1, a 30 μm thick polyester film (D2810, trade name, manufactured by Daicel Corp.) that is not subjected to aperture treatment is used. In the same manner as in Example 1 except that the sound absorbing and insulating material of Comparative Example 1 was obtained. The polyester film is partially melted during heat bonding to form voids. Various characteristics of the sound absorbing and insulating material were measured in the same manner as in Example 1, and the results are shown in Table 1.

[Example 2]
In the sound absorbing and insulating material of Example 1, after laminating the resin layer, a resin nonwoven fabric (nylon nonwoven fabric, basis weight: 20 g / m ² , air permeability: 400 ml / cm ² · sec or more) was laminated thereon as a reinforcing material. Except for the above, a sound absorbing and insulating material with a reinforcing material was obtained in the same manner as in Example 1. As a result of measuring the tear resistance of the sound absorbing and insulating material of Example 2 and the sound absorbing and insulating material of Example 1, they were 1.36 kgf / cm and 0.33 kgf / cm, respectively. Moreover, as a result of measuring the air permeability, low-temperature workability, sound absorption rate, and sound insulation of the sound absorbing and insulating material of Example 2, it was confirmed that it had the same characteristics as the sound absorbing and insulating material of Example 1.

  As shown in Table 1, the sound absorbing and insulating material of the present invention is excellent in low-temperature workability, sound insulating properties, and sound absorbing properties, and when a resin nonwoven fabric layer is provided as necessary, as is clear in Example 2 Furthermore, it can be seen that in addition to these good properties, excellent tear resistance can be achieved.

It is a schematic diagram of a perpendicular incidence sound insulation rate measuring device.

Explanation of symbols

10 Normal incident sound insulation rate measuring device 12 Sample 14 Microphone 16 Sound insulation box 18 Speaker

Claims (7)

  A sound absorbing and insulating material having a resin layer having a breathability of 1/2 to 1/50 of the foamed resin base material on the surface of the foamable resin base material having continuous breathability.   A sound-absorbing and insulating material having a resin layer made of a resin film in which an aperture is formed on the surface of a foamable resin base material having continuous air permeability.   The sound absorbing and insulating material according to claim 2, wherein a hole diameter of the resin film formed with the hole portion is 10 to 500 µm.   The sound absorbing and insulating material according to claim 1 or 2, wherein the resin layer is made of a locally thinned resin film.   The sound absorbing and insulating material according to claim 1 or 2, wherein the resin layer is made of a polyurethane film. The air permeability of the foamable resin substrate is in the range of ³ to 100 ml / cm ² · sec, and the air permeability of the resin layer is in the range of 0.06 to 50 ml / cm ² · sec. The sound-absorbing and insulating material according to any one of claims 1 to 5.   The sound absorbing and insulating material according to any one of claims 1 to 6, further comprising a resin nonwoven fabric layer on a surface of the resin layer.

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