JP2008132972A - Sound-insulating cushioning material - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a sound-insulating cushioning material excellent in impact resistance and a sound insulating property, and also excellent in ice accretion resistance. <P>SOLUTION: This sound-insulating cushioning material has an excellent sound-insulating property and impact resistance since the material has a base layer formed of a non-woven fabric. Since the sound-insulating cushioning material has a resin surface layer covering the surface of the base layer, and formed of a material containing resin, a water-absorbing property is suppressed, and ice accretion resistance is improved. By setting the Metsuke weight (weight per unit area) of the resin surface layer in a range of 50-400 g/m<SP>2</SP>, and setting a molten resin component included in the resin surface layer not smaller than 60%, the sound-insulating cushioning material excellent in impact resistance and a sound insulating property, and also excellent in ice accretion resistance can be provided. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention is mounted on the inner surface of the tire house of the vehicle body, absorbs the impact caused by the impact of foreign objects such as pebbles bounced up when the vehicle travels against the vehicle body, suppresses impact noise, and suppresses damage to the vehicle body near the tire. It relates to a soundproof cushioning material.

  For example, Patent Document 1 discloses a soundproof cushioning material (fender liner) including a nonwoven fabric in which a large number of short fibers are entangled with each other. In this way, the soundproof cushioning material formed of non-woven fabric has impact resistance and soundproofing properties (especially sound absorption) because the innumerable voids formed between the fibers intertwined with each other absorb the impact caused by the collision of foreign matter. Are better.

JP 2000-264255 A JP 2002-348767 A

  However, the sound-proof cushioning material formed only by the nonwoven fabric made of short fibers as described above easily absorbs moisture since the surface area becomes very large when the voids formed between the short fibers are exposed on the surface. For this reason, in winter, the water absorbed in the nonwoven fabric freezes, and if the ice icing on the nonwoven fabric surface grows in a direction approaching the tire, the ice interferes with the tire and adversely affects the steering performance of the vehicle. There is a fear.

  For example, the soundproofing buffer shown in Patent Document 2 is intended to improve water resistance and foreign matter adhesion by covering the surface of the soundproofing buffer formed of a nonwoven fabric with a water resistant film. However, if the surface of the nonwoven fabric is completely covered with the water-resistant film in this way, air is blocked by the water-resistant film, so that the sound absorption effect by the nonwoven fabric cannot be sufficiently exhibited.

  An object of the present invention is to provide a soundproofing cushioning material that is excellent in impact resistance and soundproofing properties, and further excellent in icing resistance.

In order to solve the above-mentioned problems, the present invention provides a sound-proof cushioning material to be mounted on the inner surface of a tire house of a vehicle body, a base layer made of a nonwoven fabric in which a number of short fibers are entangled with each other, and a resin that covers the surface of the base layer A surface layer, the resin surface layer has innumerable pores communicating the base layer and the outside air, the basis weight is 50 to 400 g / m ² , and further contains 60% or more of a molten resin component. Features.

  Thus, since the soundproofing cushioning material of the present invention has a base layer made of a nonwoven fabric having a large number of fibers intertwined with each other, excellent sound absorption and impact resistance can be obtained. Further, in this soundproofing cushioning material, the surface of the base layer is covered with a resin surface layer, thereby improving water resistance and improving icing resistance. Furthermore, by forming innumerable fine pores (porous) in the resin surface layer, the base layer formed of the nonwoven fabric is communicated with the outside air, and the sound absorption by the base layer made of the nonwoven fabric is maintained.

At this time, if the basis weight of the resin surface layer is too small, the surface of the base layer cannot be completely covered, impact resistance and sound absorption are significantly reduced, and if the basis weight of the resin surface layer is too large, an appropriate porous layer cannot be formed on the resin surface layer. The air is substantially blocked by the resin surface layer, and the sound absorption effect by the base layer cannot be exhibited. Therefore, the basis weight of the resin surface layer is preferably in the range of 50 to 400 g / m ² , for example.

  Moreover, even if the basis weight of the resin surface layer is within the above range, if the resin surface layer has too little molten resin component, the surface of the base layer may not be completely covered. It is desirable to include the above. In addition, a molten resin component means the resin component which melted | cured at the time of shaping | molding of resin surface layer, and was solidified after that.

According to the soundproofing cushioning material of the present invention, it is possible to set the water absorption rate on the surface on the resin surface side to a low level of 1.8% or less, thereby preventing the progress of icing. In addition, the water absorption mentioned here shall be measured by the following method (see FIG. 5). First, a 200 mm × 200 mm sample (soundproof cushioning material 1) is fixed on an inclined surface of 60 ° with respect to the horizontal direction, and a float 40 (caliber: φ6.0 mm) is positioned at a height of 300 mm from the center position of the sample. ). In this state, 100 cm ³ of water is dropped from the float 40 to the center position of the sample, and the weight W of the sample is measured after 1 minute. The water absorption A (%) = (W−W _0/100 ) × 100 is obtained by dividing the difference between the weight W ₀ of the sample after dropping and the weight W ₀ of the material before dropping by the amount of dropped water. .

  With such a soundproof cushioning material, it is possible to obtain excellent icing resistance such that the icing shearing force on the surface on the resin surface side is 380 N or less.

Moreover, if the air permeability of the soundproofing cushioning material is 1 cm ³ / cm ² · s or less, the sound absorption effect by the base layer cannot be exhibited, and if the air permeability is 50 cm ³ / cm ² · s or more, impact resistance And sound absorption are significantly reduced. Therefore, the air permeability of the soundproofing cushioning material is preferably in the range of 1 to 50 cm ³ / cm ² · s. Note that the air permeability referred to here is measured by the Frazier method defined in JIS L 1096.

  Such a resin surface layer can be formed, for example, by press molding a large number of resin fibers entangled with each other.

  As described above, according to the present invention, it is possible to obtain a soundproofing cushioning material that is excellent in impact resistance and sound absorption, and also excellent in icing resistance.

  Embodiments of the present invention will be described below with reference to the drawings.

  FIG. 1 shows a partial side view of the periphery of a tire 102 of an automobile equipped with a soundproof cushioning material 1 according to an embodiment of the present invention. The soundproof cushioning material 1 forms a shape along the inner surface 101a of the tire house 101 of the vehicle body 100, and is attached to the inner surface 101a.

  FIG. 2 schematically shows a cross-sectional view of the soundproofing cushioning material 1. The soundproofing cushioning material 1 includes a base layer 10 whose upper surface is attached to a vehicle body, and a resin surface layer 20 provided on the tire side of the base layer 10. In FIG. 2, the following description will be made with the upper side being the vehicle body side and the lower side being the tire side.

  The base layer 10 is made of a nonwoven fabric having a large number of short fibers 11 intertwined with each other. The base layer 10 of the present embodiment includes short fibers 11 and a binder resin 12 having a melting point lower than that of the short fibers 11, and can be molded by melting the binder resin 12 between a large number of short fibers 11 intertwined with each other. Composed. Innumerable minute voids 13 are formed inside the base layer 10 made of nonwoven fabric. For example, when a polyester fiber is used as the short fiber 11, for example, a polyester fiber modified to have a lower melting point than usual, polyethylene (PE), polypropylene (PP), or the like is used as the binder resin 12. . Further, the binder resin 12 is composed of only a low melting point resin as shown in FIG. 3 (a), and a low melting point resin 12b attached to the surface of the short fiber 12a as shown in FIG. 3 (b) ( Bicomponent fibers) can be used. The method for forming the base layer 10 is not limited to this. For example, the base layer 10 is obtained by applying a colloidal aqueous dispersion (latex) of fine resin particles to short fibers entangled with each other and heating. Can also be molded.

  The resin surface layer 20 covers the tire-side surface 14 of the base layer 10 and is exposed on the tire-side surface of the soundproofing cushioning material 1. The resin surface layer 20 occupies the main part, and is composed of a resin part 21 made of a molten resin component and a large number of short fibers 22 embedded in the resin part 21 and intertwined with each other. The strength of the resin surface layer 20 is increased by the short fibers 22. The resin portion 21 has innumerable fine holes (porous) 23 that communicate with both surfaces thereof. The resin material of the resin portion 21 is preferably a material having hydrophobicity, and for example, polyethylene, polypropylene fibers or granules, or powder can be used. Moreover, when using fibrous resin, similarly to said binder resin 12, a monocomponent fiber (refer FIG. 3 (a)) or a bicomponent fiber (refer FIG.3 (b)) can be used. As will be described later, the resin portion 21 of the present embodiment is formed by heating and melting a large number of single-component resin fibers entangled with each other. The material that can be used for the short fiber 22 is the same as that exemplified as the material that can be used for the short fiber 11 and the binder resin 12 in the base layer 10. It may be.

As described above, the soundproofing cushioning material 1 has excellent sound absorption and impact resistance by forming innumerable minute voids 13 inside the nonwoven fabric constituting the base layer 10. In addition, the sound-proof cushioning material 1 covers the surface of the base layer 10 with the resin surface layer 20 to reduce the water absorption rate, thereby improving water resistance and improving icing resistance. In particular, when the resin portion 21 of the resin surface layer 20 is formed of a hydrophobic resin material, the water resistance can be further improved. Specifically, the above effect can be obtained by setting the water absorption rate of the surface of the soundproof cushioning material 1 on the resin surface layer 20 side to 1.8% or less, preferably 1.3% or less. Furthermore, by forming an appropriate porous 23 on the resin surface layer 20 and ensuring a predetermined air permeability, the sound absorption of the base layer 10 formed of a nonwoven fabric can be sufficiently exhibited. Specifically, the above effect can be obtained by setting the air permeability within a range of 1 to 50 cm ³ / cm ² · s, preferably ^{3 to 30} cm ³ / cm ² · s. As described above, by setting the water absorption rate and air permeability within the above ranges, it is possible to obtain the soundproofing cushioning material 1 having excellent sound absorption, impact resistance, and icing resistance.

  Next, an example of the manufacturing method of such a soundproof cushioning material 1 is shown.

First, the binder resin 12 is mixed into the short fibers 11 and they are entangled with each other by needle punching, thereby forming the base layer fiber body 31 as a material for forming the base layer 10. Moreover, the resin surface layer fiber body 32 used as the material which forms the resin surface layer 20 is formed by mixing the short fiber 22 and the resin fiber 24 which forms the resin part 21, The base layer fiber is formed by this resin surface layer fiber body 32. The tire-side surface 31a of the body 31 is covered (see FIG. 4). At this time, the basis weight of the resin surface fiber body 32 is adjusted within a range of 50 to 400 g / m ² . If the basis weight is 50 g / m ² or less, the surface of the base layer 10 cannot be covered, and the soundproofing cushioning material 1 has excessive air permeability and water absorption, and the basis weight is 400 g / m ² or more. This is because an appropriate porous 23 is not formed on the resin surface layer 20 and the air permeability of the soundproofing cushioning material 1 is insufficient. In this case, for example, 50 to 250 g / m ² is a relatively small value the basis weight of the resin surface layer fibers 32, made preferably easily porous 23 is formed on the resin surface layer 20 when in the range of 100 to 200 g / m ² It is possible to obtain a soundproof cushioning material having high air permeability, that is, having high sound absorption. On the other hand, 250~400g / m ² is relatively large value basis weight of the resin surface layer fibers 32, preferably be increasing the thickness of the resin surface layer 20 when in the range of 300 to 400 g / m ^2, the resin surface layer Even when the soundproof cushioning material after forming 20 is greatly stretched and molded, the resin surface layer 20 having an appropriate porosity can be maintained.

  Further, the resin fiber 24 serving as the molten resin component has a melting point lower than the heating temperature at the time of molding described later, and 50 of the material constituting the resin surface layer fiber body 32 in order to sufficiently cover the surface of the base layer 10. % Or more, preferably 60% or more, more preferably 80% or more. As described above, by adjusting the basis weight of the resin surface layer fiber body 32 forming the resin surface layer 20 and the blending ratio of the resin fibers 24, the air permeability and the water absorption rate of the soundproofing cushioning material 1 are set within the above ranges. It becomes possible. In addition, when using bicomponent fiber as shown in FIG.3 (b) as the resin fiber 24, the part except the short fiber used as a core material, ie, the estimated amount and compounding ratio of the resin component to fuse | melt, are the above-mentioned. What is necessary is just to determine the compounding quantity of a resin fiber so that conditions may be satisfy | filled.

  By further performing needle punching on a multilayer body (hereinafter referred to as a fiber multilayer body 33) composed of the base layer fiber body 31 and the resin surface layer fiber body 32, the resin fibers 24 and the short fibers 22 of the resin surface layer fiber body 32 are provided. And the short fibers 11, the binder resin 12, the resin fibers 24, and the short fibers 22 are entangled at the interface between the base layer fiber body 31 and the resin surface layer fiber body 32.

  Subsequently, the fiber multilayer body 33 is subjected to heat treatment (preheating step). Specifically, the fiber multilayer body 33 is heated to melt the binder resin 12 of the base layer fiber body 31 and the resin fibers 24 of the resin surface layer fiber body 32. Then, it pressurizes, cooling the fiber multilayer body 33, and shape | molds in a sheet form (cooling pressurization process). As a result, the short fibers 11 are bonded to each other through the molten binder resin 12 to form the base layer 10, the molten resin fibers 24 are solidified to form the resin portion 21, and the resin surface layer 20 is configured. . Furthermore, the base resin 10 and the resin surface layer 20 are obtained by bonding the short fiber 11 and the short fiber 22 entangled with each other at the interface between the base layer fiber body 31 and the resin surface layer fiber body 32 by the melted binder resin 12 and resin fiber 24. Join. By molding the soundproof cushioning material 1 as described above, the surface of the resin portion 21, that is, the surface of the resin surface layer 20 can be smoothed, and the surface area of the soundproof cushioning material 1 can be reduced.

  When the soundproofing cushioning material 1 is used in a shape other than the sheet shape, the sheetlike soundproofing cushioning material 1 is heated again and formed into a predetermined shape by pressing (pressing process). In the present embodiment, the sheet-like soundproofing cushioning material 1 is formed into a shape along the inner surface 101a of the tire house 101 by this pressing step. Normally, this pressing step is performed by heating from the base layer 10 side of the soundproofing cushioning material 1 to melt the base layer 10 to some extent and making it re-moldable. When the surface of the surface layer 20 is sufficiently smoothed through the preheating step and the cooling and pressurizing step, press working by overheating only on one side may be performed. When the surface is not sufficiently smoothed, in this pressing step, the surface of the resin surface layer 20 can be sufficiently smoothed by heating from both sides of the soundproofing cushioning material 1 and performing pressing while cooling again.

  In the above embodiment, the surface of the resin surface layer 20 is smoothed. However, the basis weight and the blended amount of the molten resin component are within the above ranges, the resin surface layer has appropriate pores, and is sufficient. If water resistance is obtained, smoothing is not necessarily required.

  In order to confirm the usefulness of the present invention, the soundproof cushioning material according to the present invention, that is, a soundproof cushioning material (Example) composed of a base layer composed of a nonwoven fabric and a resin surface layer covering the surface, and a soundproof cushion composed only of a nonwoven fabric A material (comparative example) was prepared, and the air permeability and water absorption rate were examined. The air permeability was measured by the Frazier test method, and the water absorption rate was measured by measuring the water absorption rate of the surface layer side by the above water absorption rate measuring method.

FIG. 6 shows the composition of each sample and the measurement results. As in Examples 1 and 2, the basis weight of the surface layer and the resin blending ratio were within the ranges specified in the present invention (basis weight: 50 to 400 g / m ² , resin blending ratio: 60% or more). And water absorption can be within the ranges shown above (breathability: 1 to 50 cm ³ / cm ² · s, water absorption: 1.8% or less). On the other hand, as in Comparative Example 1, the weight per unit area of the surface layer is within the range defined by the present invention, but the resin content is outside the range defined by the present invention, the breathability is a value within the above range (12 .8 cm ³ / cm ² · s), but the water absorption was a value greatly exceeding the above range (38.2%). Moreover, the thing which mix | blended the water repellent like the comparative example 2 also became a value (2.0%) which exceeded the said range. As mentioned above, it can be said that the Example of this invention is excellent in water resistance compared with a comparative example, and by extension, is excellent in icing resistance.

  Next, using the soundproofing buffer shown in Example 2 and Comparative Example 2 in FIG. In this test, a shear load is gradually applied between the soundproofing cushioning material 1 and the ice adhering thereto, and the icing property is evaluated by the maximum value of this shear load (this value is called icing shear force). It is. Specifically, as shown in FIG. 7, first, a cylindrical ring 60 is placed on the surface (surface on the surface layer side) of the soundproof cushioning material 1 placed horizontally, and water is filled in the cylindrical ring 60 in a low temperature state. The ice 70 is adhered to the soundproofing cushioning material 1 by freezing. The soundproof cushioning material 1 to which the ice 70 is thus attached is disposed in the apparatus shown in FIG. This apparatus has a vertically arranged sample fixing plate 61, a U-shape opened upward, bolted to the sample fixing plate 61, and positioning unit 62 for positioning the sample from below and from the left and right, and ice 70. And a pressing jig 63 for applying a load from above. The soundproofing cushioning material 1 integrally provided with the ice 70 and the cylindrical ring 60 is disposed in this apparatus with the back surface (surface on the base layer side) in contact with the sample fixing plate 61. In this state, the pushing jig 63 is lowered, and the vicinity of the end of the cylindrical ring 60 near the soundproofing cushioning material 1 is pressed downward to apply a shear load between the ice 70 and the soundproofing cushioning material 1.

  The weight (N) and stroke amount (mm) by the pressing jig at this time were recorded, and the result is shown in FIG. Specifically, the maximum load, that is, the icing shear force in Comparative Example 2 was 768 N, whereas the icing shear force in Example 2 was 362 N (see FIG. 6). Therefore, it was revealed that Example 2 of the present invention had an icing shear force of 1/2 or less as compared with Comparative Example 2, and was excellent in icing resistance.

It is a partial side view which shows the tire house periphery of a vehicle body. It is an expanded sectional view showing typically the soundproofing shock absorbing material of the present invention. (A) It is a fragmentary perspective view which shows binder resin which consists of a single component fiber. (B) It is a fragmentary perspective view which shows binder resin which consists of 2 component fibers. It is an expanded sectional view showing typically the soundproofing buffer material (fiber multilayer body) before pressing. It is a front view which shows the measuring method of a water absorption. It is a table | surface which shows a composition of an Example and a comparative example. 4 is a perspective view showing a state where ice is icing on a test piece of Example 2. FIG. It is a perspective view which shows the apparatus of Example 2. FIG. 10 is a graph showing the results of Example 2.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Soundproof cushioning material 10 Base layer 11 Short fiber 12 Binder resin 13 Space | gap 20 Resin surface layer 21 Resin part 22 Short fiber 23 Porous 24 Resin fiber 31 Base layer fiber body 32 Resin surface layer fiber body 33 Fiber multilayer body 100 Car body 101 Tire house

Claims (5)

A soundproof cushioning material mounted on the inner surface of the tire house of the vehicle body, comprising a base layer made of a nonwoven fabric in which a large number of short fibers are entangled with each other, and a resin surface layer covering the surface of the base layer,
The resin surface layer has innumerable pores communicating the base layer and the outside air, the basis weight is in the range of 50 to 400 g / m ² , and further contains 60% or more of the molten resin component. Soundproof cushioning material.   The soundproofing cushioning material according to claim 1, wherein the water absorption rate of the surface of the resin surface layer is 1.8% or less.   The soundproofing cushioning material according to claim 1, wherein the icing shear force on the surface of the resin surface layer is 380 N or less. The sound-proof cushioning material according to claim 1, wherein the air permeability is in the range of 1 to 50 cm ³ / cm ² · s.   The soundproof cushioning material according to claim 1, wherein the resin surface layer is formed by press molding a large number of resin fibers entangled with each other.

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