JPH0913260A - Soundproof material - Google Patents

Abstract

PURPOSE: To obtain a readily formable fibrous soundproof material, good in sound absorbing properties and hardly causing permanent set in fatigue. CONSTITUTION: This soundproof material is obtained by forming staple fibers having >=23μm center of fiber diameter distribution as a material, arranging staple fibers containing at least >=10 pts.wt. low-melting single fibers (core-sheath fibers) as a binder therein, blowing in the resultant mixture together with air into a mold according to a blowing in method, further blowing hot air or steam, compressing and forming the mixture. The formed fiber assembly has 0.01-0.15g/cm<3> final average apparent density.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a soundproof material used in various industries such as soundproof insulators for automobiles, soundproof walls, sound absorbing materials and soundproof covers.

[0002]

2. Description of the Related Art Conventionally, for example, a PET fiber diameter is 6 denier (average fiber diameter 25 μm) or more and an apparent density is 0.0
The mainstream is composed of fibers of 6 g / cm ³ or less and layered by carding or needle punching. Generally, the larger the fiber diameter is, the easier the moldability is, but the less the sound absorbing property is. If the fiber diameter is made smaller, the sound absorbing property is improved, but the moldability becomes difficult and the settling becomes large. Also, due to carding or needle punching, the orientation of the fibers is remarkably different in the vertical and horizontal directions, so that a large difference occurs in the sound absorbing properties in the vertical and horizontal directions.

[0003]

As described above, it is often the case that the conventional fiber bodies do not always have satisfactory soundproofing performance, and the soundproofing performance in the orientation direction is reduced or reduced due to the layered molding. It often happens that the The present invention has made clear these problems as a result of intensive studies aimed at improving and solving such problems.

[0004]

According to the present invention, the first aspect of the present invention is as follows.
As described in (1), a short fiber having a center of fiber diameter distribution of 23 μm or less, more preferably 20 μm or less is used as a raw material, and this is molded into a fiber aggregate having an average apparent density of 0.01 to 0.15 g / cm ^3. A soundproofing material, characterized in that, as described in claim 2, the fiber assembly is a material in which 10 wt% or more of a short-fiber binder having a low melting surface is mixed in the short-fiber material. It is a soundproof material characterized by being used as.

Then, as described in claim 3, the fiber assembly is filled with an appropriate amount of short fibers into the mold by a filling method in which the short fiber material is blown into the mold together with air. Compression molding, and then blown into the mold with hot air or steam to be solidified and solidified to finally form a fiber aggregate having an apparent density of 0.01 to 0.15 g / cm ³ A short fiber, which is a material and is formed by a filling method in which the fiber assembly is blown into a mold together with air as described in claim 4 and is filled to an apparent density of 0.01 g / cm ³ or more, It is a soundproof material obtained by compressing and molding 15 times or less.

Further, according to claim 4, the fiber assembly has an apparent density of 0.01 g / cm 2 of the short fiber material.
³ to 0.15 g / cm ³ or less of relatively light density, for example, preformed flat plate of 0.01 to 0.03 approximately fiber aggregate, a further said preform, the apparent density 0.01
A soundproof material, characterized in that it is a fiber assembly that is compression molded to 0.15 g / cm ³ and solidified by hot air or steam.

According to a fifth aspect of the present invention, there is provided a soundproof material characterized in that the fiber assembly has a random orientation state in a direction perpendicular to the compression direction. A soundproof material obtained by flowing hot air or steam in the same direction as the compression direction when molding the fiber assembly. Further, the soundproofing material further comprises at least two layers of a low-density layer and a high-density layer as described in claim 7, wherein the low-density layer is 0.01 to 0.06 g / cm ³ , and the high-density layer is It is a soundproof material composed of 0.06 to 0.15 g / cm ³ , and further, as described in claim 8, the soundproof material is characterized in that the density continuously changes.

That is, the skeleton of the present invention has a fiber diameter of 23 μm or less, preferably 20 μm or less (for example, in the case of polyester short fibers, 5 denier or less, preferably 3 denier or less) and an apparent density of 0. 06 g
It has been found that the soundproofing performance is remarkably improved by setting it to be / cm ³ or more. . Further, in the present invention, by adopting so-called blow molding, the orientation direction can be easily made uniform in both the vertical and horizontal directions, and the difference in vertical and horizontal sound absorbing properties can be eliminated and controlled, so that the sound absorbing performance is improved as a whole compared to the conventional one. It turned out that it is possible to obtain the effect as well as to improve the fatigue.

As the short fiber material used in the present invention, synthetic fibers such as polyester, polypropylene, polystyrene, nylon, acrylic, vinylon, wool, hemp, silk and cotton or natural fibers are preferably used.

Furthermore, the binder of the low melting point composite short fiber having a core-sheath structure used for molding and solidifying the fiber aggregate having a fiber diameter of 23 μm or less used in the present invention described in claim 2 is The total short fiber content is preferably 10% by weight or more. 1
If it is less than 0% by weight, the function as a binder becomes insufficient,
Moldability is also poor.

[0011]

EXAMPLES The present invention will be described in detail below with reference to examples, but the present invention is not limited to these examples. The apparatus used in this example is shown in the schematic diagram of FIG. This example shows the case where polyester fiber is used.

[Example 1] 20% by weight of a low melting point polyester short fiber having a core-sheath structure was mixed with a polyester short fiber having an average fiber diameter of 20 μm and a length of 51 mm,
After filling it with air into a flat plate-shaped mold with 00 x 800 mm air-permeable holes (φ1.5 mm, pitch 7 mm), this time, from the same direction as the compression direction (through the air holes provided above and below) A hot blast of 200 ° C. was blown in to obtain a soundproof material formed by hot blasting into a flat surface having an apparent density of 0.07 g / cm ³ and a thickness of 20 mm.

[Embodiment 2] A material similar to that of Embodiment 1 is laminated in a card machine or the like, and an apparent density of 0.01 to 0.
A flat plate-shaped preform having a weight of 03 g / cm ³ was prepared, and the soundproof material having an apparent density of 0.07 g / cm ³ was obtained by laying this in a mold and performing compression molding while sending hot air.

COMPARATIVE EXAMPLE 1 An apparent density of 0.07 g / c was obtained in the same manner as in Example 1 except that the short fibers having an average fiber diameter of 25 μm (6 denier) were used.
A soundproofing material of m ³ was obtained.

[Comparative Example 2] A soundproof material was obtained in the same manner as in Example 2, except that the short fibers having an average fiber diameter of 25 µm were used in Example 2. Apparent density is 0.07g / cm
^{Was 3} .

Table 1 shows the compositions and results of each of the above Examples and Comparative Examples.

[0017]

[Table 1]

Further, for the performance evaluation of the above-mentioned examples and comparative examples, sound absorption coefficient, spring evaluation and solid sound evaluation were carried out, and respective results and comparisons are shown in FIGS. The evaluation methods were carried out as follows. (1) Sound absorption coefficient Normal incidence sound absorption coefficient was measured by the two-microphone method as shown in FIGS. However, the air layer behind the sound absorbing material was measured as zero. Sample size: diameter 90mm, thickness:
20 mm. (2) Spring Evaluation As shown in FIG. 4, a sample was placed on a jig fixed to a vibration exciter, and an accelerometer was mounted on the base jig and the epidermis to measure vibration and evaluate the transfer function. (3) Solid sound evaluation (electromagnetic excitation method) As shown in FIG. 5, a base panel (iron plate 0.
8mm) to generate a solid sound,
Each sample is placed on top of this, and a skin made by laminating PVC and non-woven carpet together is laminated, and the sound pressure level generated by the microphone above is measured, and the sound insulation performance against solid sound is evaluated from the difference.

[0019]

As described above, the conventional fiber-type soundproofing material has a PET fiber diameter of 6 denier (average fiber diameter 25 μm) or more and an apparent density of 0.06 g / cm 2.
^The mainstream is composed of fibers of ³ or less and layered by carding or needle punching. Generally, the larger the fiber diameter is, the easier the moldability is, but the less the sound absorbing property is. If the fiber diameter is made smaller, the sound absorbing property is improved, but the moldability becomes difficult and the settling becomes large. Also, due to carding or needle punching, the orientation of the fibers is remarkably different in the vertical and horizontal directions, so that a large difference occurs in the sound absorbing properties in the vertical and horizontal directions. As a result, when there is an end of the soundproof material or a hole, the soundproof performance around the hole is deteriorated and there is a problem such as sound leakage.

As described above, the present invention is excellent in moldability and settling property by blow molding a fiber having a smaller short fiber diameter than the conventional one, and in particular, a soundproof material which is a molded product of the present invention. However, it is possible to obtain a soundproofing material in which the difference in the orientation in the vertical and horizontal directions is very small compared to the conventional one.

[Brief description of the drawings]

FIG. 1 is a diagram showing an outline of a blowing / compression molding die used in the present invention.

FIG. 2 is a system diagram of a measuring device that measures a sound absorption coefficient.

FIG. 3 is a detailed view of the acoustic tube in FIG.

FIG. 4 is a schematic representation of an apparatus for evaluating spring properties.

FIG. 5 is a schematic sectional configuration diagram of an electromagnetic vibration device for evaluating sound insulation performance with respect to solid sound.

FIG. 6 is a graph showing the measurement results of the sound absorption coefficient in the direction perpendicular to the orientation or in the compression direction (normally considered incident direction of sound) in Example 2 and Comparative Example 2.

FIG. 7 is a graph in which the sound absorption coefficient in the direction parallel to the orientation or in the direction perpendicular to the compression is measured and compared using Example 1 and Example 2.

FIG. 8 is a graph showing the measured and compared spring characteristics of Example 1 and Comparative Example 1.

FIG. 9 is a graph showing measured and compared solid sound characteristics of Example 1 and Comparative Example 1.

[Explanation of symbols]

 A Fiber injection port B Molded surface (with ventilation holes) C Hot / cold air inlet D Hot / cold air outlet

Claims (8)

[Claims] 1. A fine short fiber having a center of fiber diameter distribution of 23 μm or less is used as a raw material, and an average apparent density of 0.01 to
A soundproof material characterized by being molded into a fiber aggregate of 0.15 g / cm ³ . 2. The fiber assembly is prepared by using, as a material, a mixture of the short fiber material and a short fiber binder having a low melting point on the surface in an amount of 10% by weight or more.
Soundproofing material according to item. 3. The fiber aggregate is filled with an appropriate amount of short fibers into the mold by a filling method in which the short fiber material is blown into the mold together with air, and compression-molded if necessary, and further in the mold. It is molded and solidified by blowing hot air or steam into it, and finally it has an apparent density of 0.01-
The soundproofing material according to claim 1 or 2, wherein the soundproofing material is a fiber aggregate of 0.15 g / cm ³ . Wherein said fiber aggregate is, density 0.01 g / cm ³ or more ~0.06g / cm ³ apparent the short fiber material
Pre-formed into the following relatively lightweight fiber aggregate flat plate,
Further, the preformed product has an apparent density of 0.01 to 0.
The soundproofing material according to any one of claims 1 to 3, which is a fiber assembly that is compression molded and solidified to have a weight of 15 g / cm ³ . 5. The soundproof material according to claim 1, wherein the fiber assembly has a random orientation state in a direction perpendicular to the compression direction. 6. The soundproofing material according to claim 1, which is obtained by flowing hot air or steam in the same direction as the compression direction when forming the fiber assembly. 7. The assembly comprises a low density layer and a high density layer.
0.01 to 0.06 g / low-density layer composed of more than one layer
The soundproofing material according to any one of 1 to 6, wherein the soundproofing material is a fiber assembly having a cm ³ density and a high-density layer of 0.06 to 0.15 g / cm ³ . 8. The soundproofing material according to claim 7, wherein the density of the aggregate changes continuously.