JP2014028611A - Soundproof material for automobile - Google Patents

Abstract

PROBLEM TO BE SOLVED: To improve performance of a soundproof material for automobiles in which chips 12 are used.SOLUTION: A soundproof material 6 is provided with a chip material layer 21 which comprises many chips 12, a skin layer 22 covering one face of the chip material layer 21, and an air-impermeable skin layer 25 covering the other face of the chip material layer 21.

Description

  The present invention relates to a soundproof material for automobiles.

  An inner fender is provided in a wheel house of an automobile fender, and a soundproofing material such as a sound absorbing material may be attached to the inner fender as a countermeasure against road noise. Patent Document 1 describes that a sound absorbing material made of a nonwoven fabric, urethane sponge, or the like is attached to an inner fender of an automobile.

  There is also known a sound absorbing material formed by laminating two or more kinds of different materials. For example, Patent Document 2 and Patent Document 3 describe a sound absorbing material for an inner fender in which a water-resistant film is laminated on a sound absorbing base material such as a nonwoven fabric.

  Patent Document 4 describes that a sound absorbing material formed by filling a breathable container with a chip-like foam is used for an automobile or the like. Examples of the breathable container include a bag made of a breathable sheet such as a non-woven fabric. Employing an olefin-based elastomer or the like as the chip-like foam, setting the size of the chip-like foam to 2 to 20 mm, It is also described that the chip-like foam is compressed and filled into a breathable container.

  Patent Document 5 describes that a sound-absorbing material obtained by enclosing pulverized foam particles obtained by pulverizing a styrene resin foam in a breathable or non-breathable bag-like material is used for an automobile or the like.

Patent Document 6 discloses a dash silencer to be mounted on a dash panel of an automobile, a non-woven fabric having a flow resistance value of 200 Nsm ⁻³ or more and 1000 Nsm ⁻³ or less, a felt having a thickness of 5 to 50 mm and an area density of 200 to 3000 g / m ² . It is described that it is made into the laminated structure.

JP 2010-006312 A Japanese Patent No. 3675359 JP 2011-240821 A JP 2005-316353 A JP 2003-150169 A JP 2002-264736 A

  For example, a fiber-based sound absorbing material such as felt or Synsalate (trademark) is widely used for an inner fender of an automobile. However, as shown in FIG. 13, the fiber-based sound absorbing material exhibits a relatively high sound absorbing performance in a high frequency range of 1500 Hz or higher, but has a low sound absorption rate in a low frequency range. That is, in automobiles, noise with a frequency of about 1000 Hz or lower due to engine noise or road noise becomes a problem, but the expected sound absorbing performance cannot be obtained with conventional fiber-based sound absorbing materials.

  Further, as described in Patent Documents 4 and 5, a foam-like or non-breathable bag is filled with a chip-like foamed elastic body, and a breathable or non-breathable sheet is formed on the layer of the chip-like foamed elastic body. Although it is also made into the state which piled up the material, the outstanding sound absorption performance is not necessarily acquired.

Further, felt is widely used as a sound absorbing material, but even if a nonwoven fabric is laminated on the felt, the sound absorbing performance is hardly changed. Figure 14 and the sound absorbing material flow resistance is formed of only the felt 10 ^{4 Ns} / m 4 orders, a normal incidence sound absorption coefficient of the sound absorbing material flow resistance by laminating 10 6 ^Ns / m ⁴ order of nonwoven this felt It is a seen graph. According to the figure, it can be seen that even if a non-woven fabric is laminated on the felt, the frequency at which the sound absorption coefficient peaks is slightly shifted to the low frequency side, and an increase in the sound absorption coefficient can hardly be expected.

  Of course, the thicker the soundproofing material, the higher the sound absorption performance, but for example, in the case of a soundproofing material provided in a narrow gap such as between the inner fender and the fender, there is a limit to increasing the thickness. There is.

  Therefore, the present invention relates to a soundproofing material for automobiles and further improves the soundproofing performance without excessively increasing the thickness thereof.

  In the present invention, in order to solve the above problems, one surface of a layer made of a chip material such as a chip-like foamed elastic body is covered with a breathable coating layer, and the other surface is covered with a non-breathable coating layer. It was made to be covered. This will be specifically described below.

  The automobile soundproofing material to be attached to an automobile presented here includes a chip material layer containing a large number of chip materials, and one surface of the chip material layer is covered with a film layer having air permeability. The other surface is covered with a non-breathable coating layer. Preferably, the outer surface of the chip material layer on which the sound to be soundproofed such as road noise enters is covered with an incident side coating layer having air permeability, and the inner surface of the chip material layer is not ventilated. It is covered with a protective coating layer.

  That is, for example, Patent Document 5 discloses a sound-absorbing material in which pulverized foam particles are enclosed in a breathable or non-breathable bag-like material, but one side of the chip material layer (for example, the side on which sound enters) ) Is covered with a breathable coating layer and the opposite side is covered with a non-breathable coating layer.

  On the other hand, according to the present invention, the sound absorbing performance in a relatively wide frequency range can be improved by the combination of the chip material layer and the air-permeable coating layer covering one surface of the chip material layer. In addition, as described above, the sound insulation effect is obtained by the non-breathable film layer covering the other surface of the chip material layer, and the sound insulation is improved as a whole.

  Here, if the inner surface of the chip material layer is covered with a non-breathable coating layer, the non-breathable coating layer on the inner side of the vehicle exhibits a waterproof effect, so that water penetrates into the chip material layer. Is prevented. Therefore, the sound absorption performance of the chip material layer can be maintained, which is advantageous for improving the durability of the soundproof material. In particular, in the case of a soundproof material to be attached to the inner fender, water is likely to be splashed thereon, so that there is a significance of making the film layer on the vehicle interior non-breathable.

More preferably, the flow resistance value in the thickness direction of the chip material layer is 1 × 10 ² Ns / m ⁴ or more and 1 × 10 ⁴ Ns / m ⁴ or less, more preferably 10 ³ Ns / m ⁴ order, The flow resistance value in the thickness direction of the film layer having air permeability is to be in the range of 10 ⁵ Ns / m ⁴ order to 10 ⁸ Ns / m ⁴ order. Thereby, the sound absorption performance which was excellent in combination with the chip material layer and the air permeable coating layer can be obtained. That is, an unexpected effect is obtained that the peak value of the sound absorption rate is remarkably higher than that of the soundproof material made of only the chip material layer, and the frequency range in which the sound absorption effect is exhibited is widened. Although this will be clarified in the sound absorption characteristic data described later, the reason why such an effect is obtained is not necessarily clear, but is considered as follows.

  That is, in the chip material layer, viscosity loss due to air movement around each chip material due to sound incidence, friction loss between air and the chip material, friction loss between chip materials, and vibration of the chip material itself It is thought that the sound absorption effect is exhibited by the internal loss due to. On the other hand, in the air-permeable film layer, not only has the sound absorbing action due to the above-mentioned viscosity and friction, but also the internal loss due to the film vibration of the film layer when sound is incident occupies a relatively large weight for sound absorption. it is conceivable that. In that case, the sound absorption rate by the coating layer becomes high at the resonance frequency at which the amplitude of the membrane vibration becomes maximum, but this resonance frequency changes according to the flow resistance value of the coating layer.

Thus, in the case of the present invention, the flow resistance value of the air-permeable coating layer is set in the range of 10 ⁵ Ns / m ⁴ order to 10 ⁸ Ns / m ⁴ order as described above. The resonance frequency of the coating layer appears in a frequency range relatively close to the frequency at which the sound absorption coefficient reaches a peak. In addition, since the coating layer having the above flow resistance value is allowed to transmit sound waves to some extent, sound absorption in the chip material layer can also be achieved. Therefore, it is considered that the sound absorption rate of the sound absorbing material as a whole is significantly increased by the addition of the sound absorbing effect by the resonance of the breathable coating layer to the sound absorbing effect of the chip material layer. The frequency at which the sound absorption coefficient reaches a peak is different between the chip material layer and the air-permeable film layer. In the film layer having a high flow resistance value, a resonance frequency appears on the lower frequency side than the chip material layer. Therefore, it is considered that the sound absorption coefficient is increased in a wide frequency range.

More preferably, the flow resistance value of the air-permeable film layer is set in the range of 10 ⁵ s / m ⁴ to 10 ⁷ Ns / m ⁴ , and the flow resistance value is 10 It is preferable to set in the range of ⁶ s / m ⁴ order to 10 ⁷ Ns / m ⁴ order.

  The chip material can be short, spherical, irregularly crushed, flaky, etc., and the shape thereof is not limited, and the material such as rubber, plastic, wood, paper, etc. is not limited. And it does not matter whether they are foamed or not. The flakes may have a rounded shape, a shape that is distorted so as to have irregularities, or a shape in which the peripheral edge is rolled up.

  It is preferable that the chip material layer has elasticity or compression recovery, but it is not always necessary that the individual chip material itself has elasticity or compression recovery. For example, the chip material layer may have elasticity or compression restoring property by curving the rounded flaky chip material elastically.

It is preferable that the dynamic longitudinal elastic modulus of the above-mentioned chip material layer is 1 × 10 ⁵ N / m ² or more and 1 × 10 ⁷ N / m ² or less in repeated operations of compression / compression release from 100 Hz to 1000 Hz. More preferably, it is 4 × 10 ⁵ N / m ² or more and 5 × 10 ⁶ N / m ² or less. Further, the loss coefficient from 100 Hz to 1000 Hz is preferably 0.05 or more and 0.5 or less, and more preferably 0.1 or more and 0.4 or less.

The density (true specific gravity) of the chip material is about 0.01 g / cm ³ or more and 1.5 g / cm ³ or less, and further about 0.03 g / cm ³ or more and 0.5 g / cm ³ or less. preferable. In particular, the bulk density of the chip material (apparent density when the chip material is filled in a container in a free state (non-compressed state)) is about 0.01 g / cm ³ or more and 0.99 g / cm ³ or less. It is preferable that it is about 0.03 g / cm ³ or more and 0.5 g / cm ³ or less.

  Preferred as the above-mentioned chip material is a chip-like foam having an irregularly crushed shape (not a regular shape such as a dice, sphere, strip, rectangular sheet, etc., but an irregular shape (an irregular shape) and irregular sizes). It is an elastic body (hereinafter referred to as “foamed elastic chip”). The average particle size is preferably about 0.5 mm to 5 mm, for example, and the particle size range is preferably about 0.1 mm to 10 mm, for example. By adopting the foamed elastic chip, the sound absorbing effect of the chip material layer is enhanced, and the thickness of the soundproof material can be changed by compressing the chip material layer. Therefore, the soundproofing material can be compressed and installed in a required installation location according to the space. For example, even when the soundproofing material is installed when the gap between the tire house portion of the fender and the inner fender is narrow, the soundproofing material can be compressed and installed according to the size of the gap. Here, since the incident-side film layer has air permeability, there is no problem in compression of the soundproofing material.

  As the foamed elastic body chip, for example, an olefin-based EPDM (ethylene-propylene-diene copolymer) rubber foam can be preferably used, but NR (natural rubber), IR (isoprene rubber), SBR ( Styrene-butadiene rubber), CR (chloroprene rubber), thermoplastic elastomer (olefin-based or styrene-based thermoplastic elastomer), soft polyvinyl chloride, or other foams made of other rubber or other elastic materials may be used. Good. However, from the viewpoint of enhancing sound absorption, the foamed elastic chip has foam cells (sponge foaming eyes) exposed on the surface without at least a part of the foam being covered with a skin layer. Is preferred. In other words, it is desirable that the uneven surface of the foam cell is exposed.

  The chip material may be a foamed chip of a thermoplastic resin (plastic) that is not an elastic material. The thermoplastic resin may be any material as long as it is used for general industrial use, such as olefin, styrene, amide, epoxy, urethane, and polyester. Polypropylene (PP), polyethylene (PE), and polymers thereof are preferable.

  The chip material may be a non-foamed chip. This is also an irregularly crushed shape (not a regular shape such as a dice, sphere, strip or rectangular sheet, but an irregular shape (an irregular shape) and irregular sizes), for example, a thick or thin sheet The surface may be crushed so that the surface becomes uneven, and a protruding part that is partially twisted on the surface may be generated. The average particle size is preferably about 0.5 mm to 10 mm, for example, excluding the twisted portion protruding from the chip material body, and the particle size range is preferably about 0.1 mm to 20 mm, for example. As a material of such a chip material, an elastic material or an inelastic material exemplified in the above-described foamed elastic chip or foamed chip is preferable.

In the chip material layer, a foamed elastic chip, a foamed chip, or a non-foamed chip may be constituted alone, or two or more of these may be mixed. Further, the chip material may be a main material (for example, 80% or more in volume ratio), and may also contain other sound absorbing materials or fillers such as fiber materials and inorganic material powders (silica, mica, etc.). Good. In addition, the thickness of the chip material layer is determined by the size of the space where the soundproofing material is installed. If the thickness is 5 mm or more and 100 mm or less, the desired soundproofing performance can be obtained. Of course, in order to further improve the sound absorption performance, the thickness can be increased beyond 100 mm. The surface density of the entire soundproofing material may be about 1 kg / m ² or more and 4 kg / m ² or less.

A nonwoven fabric or a woven fabric made of natural fibers or chemical fibers can be preferably used for the air-permeable coating layer. Of course, the chemical fiber may be an organic fiber or an inorganic fiber, or may be paper, and the material thereof is not particularly limited. For example, a resin sheet having no air permeability may be provided with a large number of air holes. The thickness of the air-permeable coating layer is preferably about 0.01 mm or more and 3 mm or less, and more preferably 1.0 mm or less. In addition, the surface density of the incident-side coating layer is, for example, preferably 80 g / m ² or more and 500 g / m ² or less, and more preferably 150 g / m ² or less. Here, as for what provided many air holes in the resin-made sheet | seat which does not have air permeability, the material is polyethylene and the thickness of a film layer is 0.01 mm or more and 1 mm or less, Preferably it is 0.5 mm or less. Conceivable.

As the material of the non-breathable coating layer, a polyethylene sheet having a flow resistance value of about 1 × 10 ⁹ Ns / m ⁴ or more having a thickness of about 0.01 mm to 0.5 mm and other resin sheets may be employed.

  The soundproofing material according to the present invention can be obtained, for example, by enclosing a large number of chip materials in a flat bag (a flat bag having few irregularities and flat). That is, the flat bag includes a non-breathable sheet on the inside, and a chip material is filled between one side of the flat bag and the non-breathable sheet. In this case, one side of the flat bag forms the breathable film layer, the non-breathable sheet forms the non-breathable film layer, and the one side of the flat bag and the non-breathable sheet The plurality of chip materials filled in between form the chip material layer.

  For example, the flat bag is obtained by sandwiching the sheet material forming the air-impermeable film layer between two sheet materials forming both surfaces of the flat bag and joining the peripheral portions of the three stacked sheets. Can be obtained by: The overlapped peripheral edge portion only needs to be joined to such an extent that the contents such as the chip material do not come out, and the joining is not limited to heat fusion, and an appropriate method such as adhesion and stitching is adopted. be able to. Alternatively, one sheet material may be folded and stacked so that the sheet material for the non-breathable coating layer is sandwiched therebetween, and the overlapped peripheral portions of these sheet materials may be joined. . In this case, the folded sheet material forms both sides of the flat bag.

  As described above, according to the present invention, since one surface of the chip material layer is covered with the air-permeable film layer and the other surface is covered with the air-impermeable film layer, the thickness of the soundproof material is reduced. The soundproofing performance can be improved without excessively increasing the depth.

It is a perspective view which shows an example of the motor vehicle using the soundproof material which concerns on this invention. It is a perspective view which shows an inner fender and a soundproof material. It is a perspective view which cuts and shows the said soundproof material partially. It is a perspective view which shows the example of manufacture of the said soundproof material. It is sectional drawing (enlarged drawing of the dashed-dotted circle A part of FIG. 3) of the said soundproof material. It is a graph which shows the dynamic longitudinal elastic modulus of a chip material layer. It is a graph which shows the loss coefficient of a chip material layer. It is a graph which shows the sound absorption characteristic of a soundproof material sample. It is a graph which shows the relationship between the compression rate of a chip material layer, and a flow resistance value. It is a graph which shows the influence which the compression rate of a chip material layer has on the sound absorption characteristic of a soundproof material. It is the graph which looked at the influence which the kind of chip material and the presence or absence of a non-breathable membrane layer give to the sound absorption characteristic. It is the graph which looked at the influence which the kind of chip | tip material and the presence or absence of a non-air-permeable film layer have on transmission loss. It is a graph which shows the sound absorption characteristic of the conventional fiber-type sound-absorbing material. It is the graph which saw the normal incidence sound absorption coefficient of the sound-absorbing material which consists only of a felt, and the sound-absorbing material which laminated the nonwoven fabric on this felt.

  Hereinafter, embodiments for carrying out the present invention will be described with reference to the drawings. The following description of the preferred embodiments is merely exemplary in nature and is not intended to limit the invention, its application, or its use.

<Examples of automobiles that use soundproofing materials>
FIG. 1 shows an automobile 1 as an example using the soundproofing material according to the present invention. In the figure, reference numeral 2 denotes a front fender, and an inner fender 5 shown in FIG. 2 is provided as a lining inside the tire house 3 (on the tire 4 side). The inner fender 5 prevents scratches, rust, noise and the like inside the front fender 2 due to pebbles and water that the tire 4 jumps up. As shown in FIG. 2, a soundproof material 6 is mounted on the upper surface side (the surface opposite to the tire 4) of the inner fender 5 as a countermeasure against road noise and other noises. The soundproof material 6 is provided with a water drain hole 7. The soundproofing material 6 is also attached to other parts of the vehicle body such as the inner fender 8 and the dash panel 9 on the rear fender side, the upper surfaces of the under floor covers 10a to 10c, the side door 26, the roof 27, etc. in order to obtain a quiet interior. can do.

  Further, the drain hole 7 may be an attachment hole used for attaching to the inner fender 5. In addition, the soundproofing material 6 has a joint at the peripheral edge as will be described later, and the joint is bonded partially or over the entire circumference (adhesive with the adhesive or the material of the joint), or a stapler or a bolt. It can fix to the inner fender 5 with a fastener.

<About soundproof material>
As shown in FIG. 3, the soundproofing material 6 according to this embodiment is configured by enclosing a chip material 12 in a flat bag 11. The flat bag 11 is closed over the entire circumference. This will be specifically described below.

  The flat bag 11 includes two nonwoven fabrics 13 and 14 having air permeability that form both sides of the bag and a non-breathable sheet 15 inside the bag. For example, the nonwoven fabrics 13 and 14 are made of chemical fibers of polyethylene (PE) and polyethylene terephthalate (PET), and the air-impermeable sheet 15 is made of polyethylene (PE). The peripheral portions of the nonwoven fabrics 13 and 14 and the non-breathable sheet 15 are joined over the entire circumference, and for example, heat fusion is employed for this joining. The chip material 12 is filled between the nonwoven fabric 13 and the non-breathable sheet 15. The individual chip materials 12 are non-adhered to each other and can be displaced. The chip material 12 is not bonded to each of the nonwoven fabric 14 and the non-breathable sheet 15. Moreover, in the flat bag 11, the nonwoven fabric 14 and the non-breathable sheet | seat 15 are not mutually adhere | attached.

  FIG. 4 shows the flat bag material 16 before enclosing the chip material 12. The flat bag material 16 has a body portion 17 and a tip insertion portion 18 connected by a neck portion 19, and a tip insertion portion 20 is provided in the tip insertion portion 18. A non-breathable sheet 15 is provided inside the flat bag material 16. The chip material 12 is filled between the nonwoven fabric 13 and the non-breathable sheet 15 of the trunk portion 17 from the insertion port 20 of the chip insertion portion 18. After filling, the neck portion 19 of the flat bag material 16 is closed by heat fusion or the like. When the chip insertion part 18 is cut off from the body part 17 filled with the chip material 12, the soundproofing material 6 is obtained. The body portion 17 of the flat bag material 16 becomes the flat bag 11.

  As shown in FIG. 5, in the soundproof material 6, a large number of chip materials 12 interposed between the nonwoven fabric 13 of the flat bag 11 and the air-impermeable sheet 15 form a chip material layer 21. In this example, sound is incident from the bottom to the top of the figure, and the nonwoven fabric 13 forms the outer surface of the chip material layer 21 on which sound targeted for sound insulation is incident, that is, the incident-side coating layer 22. doing. The nonwoven fabric 14 and the non-breathable sheet 15 covering the inner surface of the chip material layer 21 opposite to the incident surface of the target sound form the back-side film layer 23. In the back side film layer 23, the nonwoven fabric 14 forms a breathable film layer 24, and the non-breathable sheet 15 forms a non-breathable film layer 25. As described above, the back-side coating layer 23 has a two-layer structure of the breathable coating layer 24 and the non-breathable coating layer 25, and enhances the effect of sound absorption or sound insulation. Although not shown, an air layer may be provided by separating the layers. Further, the incident-side coating layer 22 and the back-side coating layer 23 are not bonded to the chip material layer 21.

  As shown in FIG. 2, the soundproof material 6 is stacked on the vehicle body so that the incident-side coating layer 22 is in contact with the upper surface of the inner fender 5. In FIG. 5, the inner fender 5 is indicated by a two-dot chain line, and the incident side coating layer 22 and the inner fender 5 are not bonded. A gap may be formed between the back-side coating layer 23 and the tire house 3 of the front fender 2. Then, as described above, the joint portion of the peripheral portion of the soundproof material 6 is fixed to the inner fender 5. In the present embodiment, the joint portion of the peripheral portion of the soundproof material 6 is partially fixed to the inner fender 5 by heat fusion. The soundproof material 6 may be installed so that the film layer 23 having the air-impermeable film layer 25 is in contact with the upper surface of the inner fender 5.

In the soundproof material 6 of this embodiment, the flow resistance value in the thickness direction of the chip material layer 21 is on the order of 10 ³ Ns / m ⁴ . The flow resistance value in the thickness direction of each of the incident-side coating layer 22 and the rear-side air-permeable coating layer 24 is in the range of 10 ⁵ Ns / m ⁴ to 10 ⁸ Ns / m ⁴ . The flow resistance value in the thickness direction of the non-breathable coating layer 25 on the back side is 1 × 10 ⁹ Ns / m ⁴ or more (non-breathable). When the chip material 12 is a foamed elastic chip, the average particle diameter is 0.5 mm or more and 5 mm or less (in the individual particles, the maximum diameter is distributed to about 0.1 mm to 10 mm), and the foam density is It is 0.01 g / cm ³ or more and 0.99 g / cm ³ or less. The thickness of the chip material layer 21 is 5 mm or more and 100 mm or less (it is possible to increase the thickness beyond 100 mm). The incident-side coating layer 22 and the back-side breathable coating layer 24 each have a thickness of 0.01 mm or more and 3 mm or less. The thickness of the non-breathable coating layer 25 is 0.01 mm or more and 0.5 mm or less.

<Dynamic longitudinal elastic modulus and loss factor of chip material layer>
As a chip material, an elastic foam chip obtained by pulverizing an end material of a sound insulating sheet made of an EPDM rubber foam (sponge material) into a chip shape, a flaky PE chip obtained by pulverizing a polyethylene sheet, and Prepared. An uncompressed chip material layer in which only foamed elastic chips are stacked to a thickness of 40 mm, an uncompressed chip material layer in which only PE chips are stacked to a thickness of 40 mm, and a foamed elastic chip and a PE chip The dynamic longitudinal elastic modulus and loss factor of each uncompressed chip material layer obtained by stacking mixed chips mixed at a mass ratio of 1: 1 to a thickness of 40 mm were measured.

  For the measurement, a dynamic longitudinal elastic modulus was measured by a resonance method using a vibrator that repeatedly operated in the thickness direction. The loss factor was calculated by the half-width method from the resonance point. The results are shown in FIGS.

As shown in FIG. 6, the dynamic longitudinal elastic modulus of the chip material layer at 100 Hz to 1000 Hz is 1 × 10 ⁵ N / m ² or more and 1 × 10 ⁷ for all of the foamed elastic chip, the PE chip, and the mixed chip. N / m ² or less, and further 4 × 10 ⁵ N / m ² or more and 5 × 10 ⁶ N / m ² or less.

  As shown in FIG. 7, the loss factor of the chip material layer at 100 Hz to 1000 Hz is 0.05 or more and 0.5 or less for all of the foamed elastic chip, the PE chip, and the mixed chip, and further 0.1 It is 0.4 or less.

<Characteristic evaluation 1 of soundproof material>
-Sample-
The soundproofing material samples A to D having a two-layer structure including the chip material layer 21 and the incident side coating layer 22 and the soundproofing material sample E composed only of the chip material layer 21 were produced. Samples A to D have different flow resistance values of the incident-side coating layer 22 from each other. The breathable coating layer 24 on the back side was not installed.

As the chip material constituting the chip material layer 21 of each of the samples A to E, the above-described foamed elastic chip (chip of EPDM rubber foam (sponge material)) was employed. The foamed elastic chip has an average particle size of about 2 mm and a foam density of about 0.3 g / cm ³ . Further, this chip material layer 21 exhibits the characteristics in the preferable ranges of the dynamic longitudinal elastic modulus and the loss coefficient described above, the thickness is 45 mm, the surface density is 2.5 kg / m ² , and the flow resistance value in the thickness direction. Is on the order of 10 ³ Ns / m ⁴ . This flow resistance value was measured in a non-compressed state in which foamed elastic chips were stacked to a thickness of 45 mm. The flow resistance value in the present invention is measured in accordance with the ISO 9053 DC method.

As shown in Table 1, the incident side coating layers 22 of Samples A to C were formed of nonwoven fabrics having different flow resistance values. The incident side coating layer 22 of Sample D was formed of a non-breathable polyethylene sheet having a thickness of 0.08 mm and a flow resistance value of 1 × 10 ⁹ Ns / m ⁴ or more. In the samples A to C, the incident-side coating layer 22 has a thickness of 0.5 mm and an areal density of about 100 g / m ² . Here, in this document, non-ventilation is defined as a flow resistance value of 1 × 10 ⁹ Ns / m ⁴ or more.

-Characterization-
The normal incident sound absorption coefficient in the uncompressed state of each of the samples A to E was measured according to JIS A1405-2. The results are shown in FIG. In addition, the numerical value attached | subjected to the sample symbol of the figure represents the flow resistance value (unit; Ns / m < ⁴ >) of the incident side membrane | film | coat layer.

Sample E consisting only of the chip material layer 21 exhibits sound absorption characteristics having a sound absorption coefficient peak near 1250 Hz. On the other hand, sample A using a nonwoven fabric having a flow resistance value of 4.1 × 10 ⁵ Ns / m ⁴ for the incident side coating layer 22 has a lower sound absorption coefficient peak position than sample E without the incident side coating layer. Slightly shifted to the frequency side, the sound absorption coefficient is high in a wide frequency range from 200 Hz to 2000 Hz. In sample B using a nonwoven fabric having a flow resistance value of 2.8 × 10 ⁶ Ns / m ⁴ , the sound absorption rate near 2000 Hz is slightly lowered, but the sound absorption peak position is further shifted to the lower frequency side, and the sound absorption is reduced. The rate is higher than that of sample A in a wide frequency range from 200 Hz to 1800 Hz.

In the case of Sample C using a nonwoven fabric having a flow resistance value of 4.2 × 10 ⁸ Ns / m ⁴ , the peak value of the sound absorption coefficient is high, but the shift amount of the peak position to the low frequency side is large, The sound absorption coefficient in the vicinity of 1200 Hz to 1500 Hz is low. However, the decrease in the sound absorption coefficient in the vicinity of 1200 Hz to 1500 Hz is not so large, and as a whole, it can be said that a high sound absorption coefficient is obtained in a wide frequency range.

  In sample D using a non-breathable polyethylene sheet for the incident-side film layer 22, the amount of the sound absorption peak shifts to a low frequency side, and the sound absorption coefficient drops significantly in the frequency range of 800 Hz or higher. ing.

From the comparison between the sound absorption characteristics of sample B and the sound absorption characteristics of sample C in FIG. 8, even when the flow resistance value of the incident-side coating layer 22 is set to the order of 10 ⁷ Ns / m ⁴ , the sound absorption coefficient is high in a wide frequency range. Can understand.

  From the above characteristic evaluation 1, it can be seen that excellent sound absorption characteristics can be obtained in a wide frequency range according to the combination of the chip material layer 21 according to the present invention and the incident side coating layer having air permeability.

<Characteristic evaluation 2 of soundproof material>
-Sample-
A soundproof material sample F having a laminated structure composed of the chip material layer 21, the incident-side coating layer 22, and the back-side coating layer 23 (the breathable coating layer 24 and the non-breathable coating layer 25) was produced. For the chip material layer 21, the same foamed elastic chip (EPDM rubber foam (sponge material) chip) as in the previous characteristic evaluation 1 was adopted. The chip material layer 21 has a thickness of 40 mm, an areal density of 2.0 kg / m ² , and a flow resistance value in the thickness direction in an uncompressed state is 1 × 10 ³ Ns / m ⁴ . Similar to the incident side coating layer 22 of the sample B, the incident side coating layer 22 and the rear side air permeable coating layer 24 have a flow resistance value of 2.8 × 10 ⁶ Ns / m ⁴ and a thickness of 0. A 5 mm non-woven fabric was employed. For the non-breathable coating layer 25 on the back side, a non-breathable polyethylene sheet having a flow resistance value of 1 × 10 ⁹ Ns / m ⁴ or more was employed.

-Characterization-
The flow resistance value in the thickness direction in each compressed state in which the chip material layer 21 was compressed by 10% to 50% in 10% increments was measured. The results are shown in FIG. The flow resistance value increases as the compression ratio increases, but it is 9 × 10 ³ Ns / m ⁴ even at 50% compression, and is on the order of 10 ³ Ns / m ⁴ .

  Next, regarding the sample F, the normal incident sound absorption coefficient in the uncompressed state and the normal incident sound absorption coefficient in each compressed state in which the chip material layer 21 is compressed by 10% to 50% in 10% increments are evaluated previously. It was measured by the same method as 1. The results are shown in FIG.

  From FIG. 8 and FIG. 10, the sound absorption coefficient in the uncompressed state is higher than that of the previous sound absorbing material sample B in the range of 500 Hz to 2000 Hz. This is recognized as a result of the difference in the surface density of the chip material layer 21 and the presence / absence of the back side coating layer 23.

  Thus, according to FIG. 10, as the compression rate of the chip material layer 21 increases (the flow resistance value increases), there is a tendency that the shift of the peak position of the sound absorption rate toward the high frequency side increases. However, the amount of decrease in the sound absorption coefficient on the low frequency side due to the shift is small, and high sound absorption performance in a wide frequency range is the same as in the uncompressed state.

That is, if the flow resistance value of the chip material layer 21 is on the order of 10 ³ Ns / m ⁴ , even if the flow resistance value increases within the range of the order, the peak position of the sound absorption coefficient is slightly shifted toward the high frequency side. It can be said that high sound absorption performance can be obtained in a wide frequency range.

<Characteristic evaluation 3 of soundproof material>
-Sample G-
A soundproof material sample G in which one surface of the chip material layer 21 is covered with a non-woven fabric as a breathable coating layer and the other surface is covered with a non-woven fabric as a breathable coating layer and a polyethylene sheet as a non-breathable coating layer. Was made. The nonwoven fabric and the polyethylene sheet on the other side were overlapped so that the polyethylene sheet was inside.

For the chip material layer 21, the same foamed elastic chip (EPDM rubber foam (sponge material) chip) as in the previous characteristic evaluation 1 was adopted. The chip material layer 21 has a surface density of 2.5 kg / m ² and a flow resistance value in the thickness direction in an uncompressed state of 2 × 10 ³ Ns / m ⁴ . The nonwoven fabric has a thickness of 0.55 mm and a flow resistance value of 4 × 10 ⁵ Ns / m ⁴ . The polyethylene sheet has a thickness of 0.08 mm and a flow resistance value of 1 × 10 ⁹ Ns / m ⁴ or more.

-Sample H, I-
The above-mentioned PE chip is adopted as the chip material, the other is the soundproof material sample H having the same configuration as the sample G, and the mixed chip (the foamed elastic chip and the PE chip are mixed at a mass ratio of 1: 1) as the chip material. The soundproofing material sample I having the same configuration as that of the sample G was employed. The surface density of the chip material layer by the PE chip and the surface density of the chip material layer by the mixed chip are both 2.5 kg / m ² .

Sample J-
A soundproof material sample J (without a non-breathable coating layer) in which both surfaces of the chip material layer 21 were covered with a nonwoven fabric was produced. The surface density and flow resistance value of the chip material and the chip material layer 21 are the same as those of the sample G, and the nonwoven fabric is also the same as the sample G.

-Characterization-
The normal incidence sound absorption coefficient in the uncompressed state of the samples G to J was measured by the same method as in the previous case. However, in the samples G to I including the polyethylene sheet, the sound was incident from the side where the nonwoven fabric and the polyethylene sheet were overlapped, and the measurement was performed with the nonwoven fabric on the opposite side omitted. In the sample J not provided with the polyethylene sheet, the measurement was performed with the light incident from the surface provided with the nonwoven fabric and the nonwoven fabric on the opposite side omitted. The results are shown in FIG. Samples G to I having the non-breathable coating layer 25 on the back side have a sound absorption coefficient peak position shifted to a lower frequency side than the sample J having no non-breathable coating, and have a sound absorption performance at 500 to 1000 Hz. I know it ’s good. It can also be seen that Sample G, Sample H, and Sample I all show similar sound absorption characteristics.

  The transmission loss of the samples G to J in an uncompressed state was measured. However, unlike the measurement of the normal incident sound absorption coefficient, the sound was incident from the side where only the nonwoven fabric was provided, not the side where the nonwoven fabric and the polyethylene sheet were overlapped. The results are shown in FIG. It can be seen that the non-breathable coating layer 25 increases transmission loss and increases sound insulation.

  Further, according to FIGS. 11 and 12, the sound absorption characteristics and sound insulation characteristics are slightly different depending on the type of chip material (foamed elastic chip, PE chip and mixed chip), but there is no great difference, and any chip material is adopted. However, it can be seen that good sound absorption characteristics and sound insulation characteristics can be obtained.

<Others>
In the said embodiment, although the example which attaches and uses the soundproof material which concerns on this invention to the inner fender of a motor vehicle was demonstrated, it can use not only for this but for other site | parts, such as a dash panel of a motor vehicle.

  The soundproofing material according to the present invention can also be used in a mode in which sound is incident mainly from the side covered with the non-breathable film.

DESCRIPTION OF SYMBOLS 1 Car 2 Front fender 5 Inner fender 6 Soundproof material 11 Flat bag 15 Non-breathable coating 12 Chip material 21 Chip material layer 22 Incident side coating layer 23 Back side coating layer 24 Breathable coating layer 25 Non-breathable coating layer

Claims (8)

A soundproofing material for automobiles attached to automobiles,
Provided with a chip material layer containing a large number of chip materials,
One surface of the chip material layer is covered with a film layer having air permeability,
A soundproof material for automobiles, wherein the other surface of the chip material layer is covered with a non-breathable film layer. In claim 1,
The outer surface of the chip material layer on which sound targeted for sound insulation is incident is covered with a breathable incident-side coating layer, and the inner surface of the chip material layer is covered with a non-breathable coating layer. A soundproofing material for automobiles. In claim 1 or claim 2,
The chip material layer has a flow resistance value in the thickness direction of the order of 10 ³ Ns / m ⁴ ,
A soundproof material for automobiles, wherein the film layer having air permeability has a flow resistance value in the thickness direction of the order of 10 ⁵ Ns / m ⁴ to 10 ⁸ Ns / m ⁴ . In any one of Claim 1 thru | or 3,
The chip material layer has a dynamic longitudinal elastic modulus at 100 Hz to 1000 Hz of 1 × 10 ⁵ N / m ² or more and 1 × 10 ⁷ N / m ² or less, and a loss coefficient of 0.05 or more and 0.5 or less. A soundproofing material for automobiles. In any one of Claims 1 thru | or 4,
The chip material has a bulk density (apparent density when the chip material is filled in a container in a free state (non-compressed state)) of 0.01 g / cm ³ or more and 0.99 g / cm ³ or less, preferably 0. automotive soundproofing material, characterized in that at .03g / cm ³ or more 0.5 g / cm ³ or less. In any one of Claims 1 thru | or 5,
A lot of chip materials are enclosed in a flat bag,
The flat bag is provided with a non-breathable sheet on its inner side, and the multiple chip materials are filled between one side of the flat bag and the non-breathable sheet,
One side of the flat bag forms the breathable film layer, the non-breathable sheet forms the non-breathable film layer, and between the one side of the flat bag and the non-breathable sheet A soundproof material for automobiles, wherein the plurality of filled chip materials form the chip material layer. In any one of Claims 1 thru | or 6,
The chip material layer includes a chip made of a foam of an olefin-based elastic material, a chip made of a foam of an olefin-based inelastic material, a chip made of a non-foamed material of an olefin-based elastic material, and a non-foamed material of an olefin-based inelastic material. A soundproofing material for automobiles, comprising one kind selected from chips comprising a body, or a mixture of two or more kinds. In any one of Claims 1 thru | or 7,
The chip material is made of EPDM rubber and / or polyethylene, and is a soundproof material for automobiles.

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