JP2000008260A - Sound-absorbing material - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a sound absorbing material having good sound-absorbing performance, heat resistance and flame retardance by accumulating and integrating nonwoven fabrics consisting of flame retardant fibers with substrates consisting of inorganic fibers and/or polymeric compound. SOLUTION: This acoustic material is obtained by laminating nonwoven fabrics consisting of acrylonitrile-based flame resistant fiber covered with vermiculite powder and/or zeolite powder or the like and satisfying the formula: bulk density (kg/cm3) × basis weight (g/m2)=8,000-20,000 and substrates consisting of inorganic fiber such as glass fiber and/or polymeric compound such as a foamed urethane resin in 3-7 layers preferably 4-6 layers.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a sound absorbing material which is excellent in sound absorbing performance, heat resistance and flame retardancy.

[0002]

2. Description of the Related Art Conventionally, glass fiber,
BACKGROUND ART High molecular compounds represented by inorganic fibers such as rock wool and foamed polyurethane resin are known. However, as the number of noise sources including automobile noise increases and the regulations on noise become stricter, a sound absorbing material having higher performance sound absorbing performance is required in order to prevent noise pollution.

[0003]

The present inventors have studied in detail the correlation between the sound absorbing performance and the structure of a conventional sound absorbing material, for example, the type of fiber or resin, single yarn denier or thickness, porosity, and the like. By using a fiber structure having a specific structure, it has been found that the sound absorbing performance is dramatically improved, and the present invention has been achieved.

It is an object of the present invention to provide excellent sound absorbing properties,
An object of the present invention is to provide a sound absorbing material having excellent flame resistance.

[0005]

The present invention provides a sound absorbing material in which a nonwoven fabric made of oxidized fiber and a base made of inorganic fiber and / or polymer compound are laminated and integrated,
The sound absorbing material, wherein the nonwoven fabric satisfies the following expression. Bulk density (kg / m ³ ) × weight (g / m ² ) = 8000
200,000 In the present invention, the flame-resistant fiber is obtained by performing a flame-proof treatment by a known method using an organic fiber such as an acrylonitrile fiber, a rayon fiber, a pitch fiber, and a phenol fiber as a precursor.

The fineness of the flame-resistant fiber is 0.5 to 3 denier.
Preferably, short fibers or long fibers may be used. Features of the present invention
Is a non-woven fabric composed of such flame-resistant fibers
(Kg / m ^Three) × weight (g / m^Two) = 8000-200
000, preferably 9000 to 200,000, more preferably
Or 10,000 to 200,000, more preferably 1
2000 to 200,000. This value is less than 8000
Does not improve the sound absorption performance. This value exceeds 20,000
However, the sound absorption performance is not improved.

[0007] In the present invention, to improve the sound absorbing performance, the bulk density of the nonwoven fabric is preferably 50~250kg / m ^3, more preferably 60~250kg / m ^3, most preferably at 65~250kg / m ³ . The basis weight of the nonwoven fabric is 120 to 1000 g / m2 for improving the sound absorbing performance.
² is preferable, and more preferably 150 to 1000 g / m.
² , most preferably from 200 to 800 g / m ² .

The thickness of the nonwoven fabric is preferably from 2 to 20 mm, more preferably from 2.5 to 2 in order to improve the sound absorbing performance.
0 mm. In the present invention, the bulk density (kg / m ³ )
X Non-woven fabric satisfying the basis weight (g / m ² ) = 8000 to 200,000 is, for example, a needle-punched non-woven fabric.
By increasing the number of needle punches, a nonwoven fabric by columnar flow entanglement can be easily obtained by experimentally changing the nozzle diameter, flow velocity, columnar flow pressure, and the like.

It is preferable that the surface of the oxidized fiber is coated with vermiculite particles and / or sepiolite particles, because an oxidized nonwoven fabric with less embrittlement due to heat or light can be obtained. Vermiculite is what is known mineralogically or commercially as vermiculite, and contains a vermiculite layer (for example, hydrobiotite vermiculite or chlorite vermiculite) as a constituent and the same method as that for vermiculite. And all or almost all vermiculite inorganic substances, including mixed layer type inorganic substances (layered silicates) which can be delaminated.

As a typical chemical formula, the following formula (1)

[0011]

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Are known. Preferably, the structural formula is the following formula (2)

[0013]

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Alternatively, the following formula (3)

[0015]

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The fibrous or pulp-like material is excellent in the coating property of the oxidized fiber. The vermiculite particles are preferably 200 μm or less, more preferably 50 μm.
m or less. The aspect ratio (value obtained by dividing length or width by thickness) is preferably 10 or more, and more preferably 1000 or more. Each vermiculite plate has a thickness of 10 to 4200 angstroms, an average particle diameter of 10 to 30 μm, and an aspect ratio of 10,000.
Those having a large value of up to 25,000 are preferable because they have excellent covering properties of the oxidized fiber.

[0017] In such vermiculite, the thin plate pieces are superimposed on several layers, and cover the oxidized fiber like a sheath. Therefore, the use of this material improves the weather resistance of the sound absorbing material.
Sepiolite has a hydrated magnesium silicate composition, and its chemical composition is represented by the following formula (4)

[0018]

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## EQU1 ## Sepiolite particles are 100
μm or less, preferably having a particle size of 50 μm or less, the particle size is 0.1 to 0.5 μm, the length is 5 to 50 μm
m is particularly preferable because it is excellent in the coating property of the oxidized fiber. While the heat resistance of vermiculite particles is about 1100 ° C., that of sepiolite particles is 1300 to 14
The heat resistance is as high as about 00 ° C., and the former is preferably used for applications requiring high weather resistance, and the latter is preferably used for applications requiring high heat resistance.

In order to coat the surface of the flame-resistant fiber with the vermiculite particles or the sepiolite particles, for example, the dispersion of the vermiculite particles or the sepiolite particles is dipped and coated, or a film is prepared from the dispersion of the vermiculite particles or the sepiolite particles in advance. It is achieved by laminating.

The coating or laminating may be performed on one side or both sides of the flame-resistant nonwoven fabric, and may be appropriately selected according to the application. Especially when applying by the dipping method,
When boric acid is added, the coating of the oxidized fiber with vermiculite particles or sepiolite particles is improved. The amount of addition is usually 0.1 to 10% owf (weight ratio to fiber weight).

In order to improve the durability of the coating of the vermiculite particles and the sepiolite particles, an organic binder such as an acrylic resin or a polyurethane resin is usually used in an amount of 0.1 to 0.1%.
It is preferable to add 10% owf. The amount of vermiculite particles or sepiolite particles may be appropriately selected according to the desired level of heat resistance and weather resistance.
150 g / m ² or more, more preferably 10 g / m ² or more.
g / m ² or more, most preferably 20 to 80 g / m ^2. The vermiculite particles and the sepiolite particles may be appropriately mixed as desired, for example, after coating the former, double coating to coat the latter, coating one side with the former, and then coating the other side with the latter.

The present invention is obtained by laminating and integrating a nonwoven fabric of such a specific flame-resistant fiber and a substrate composed of an inorganic fiber and / or a polymer compound. As inorganic fibers,
Glass fiber, asbestos fiber, alumina fiber, silica fiber, rock wool, slag wool and fibers made of a mixture thereof, etc., as the organic polymer compound, polyethylene, polypropylene, polystyrene, polyacrylonitrile, polyester, polyamide, polyurethane, Cellulose-based polymer compounds, rubbers and copolymers thereof, such as resin and fibers, generally include one or more organic polymer compounds in general, and glass fibers and foamed resins, particularly foamed polyurethane resins, are preferred in terms of sound absorption performance. preferable.

In applications where functions such as heat resistance and flame retardancy are required, known additives to which various additives such as flame retardants are added can be used. It is excellent in heat resistance and flame retardancy, and therefore, a combination with a substrate provided with a heat resistance or flame retardancy function is preferable.
The simplest and most effective method for laminating and integrating these is a method in which a phenol resin, an epoxy resin, a silicon resin, a fluorinated ethylene resin or the like, and particularly a flame-retardant grade resin is used as an adhesive and bonded by spot bonding or whole surface bonding. However, in the case of fibers, known entanglement means such as a needle punch, a columnar flow with high-pressure water, or the like may be used or used in combination with an adhesive.

The number of layers is preferably 3 to 7 layers, more preferably 4 to 6 layers. As the combination of the nonwoven fabric and the substrate of the flame-resistant fiber, for example, forming the front and back surfaces by sandwiching the nonwoven fabric with the nonwoven fabric as the intermediate layer, forming the front and back surfaces by sandwiching the nonwoven fabric with the base material as the intermediate layer, What is necessary is just to select the kind and lamination form of a base material according to a use.

Depending on the application, a metal thin film such as an aluminum foil may be used in combination. The thickness of the laminated sound absorbing material is preferably 5 to 100 mm, more preferably 5 to 5 mm.
0 mm. The sound-absorbing material of the present invention is suitable for applications requiring heat resistance and flame retardancy, and is suitable as a sound-absorbing material for engines of automobiles such as trucks, for example, where noise regulations are strict.

[0027]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below with reference to examples. The evaluation method in the present invention is as follows. Sound absorption performance; normal incidence method sound absorption coefficient Frequency according to JIS-A1405; 1/3 octave band center frequency

[0028]

Example 1 Fineness 2d using acrylic fiber as a precursor,
Needle-punched nonwoven fabric with a fiber length of 51 mm (registered trademark: Rastan, manufactured by Asahi Kasei Kogyo Co., Ltd.)
0 g / m ² × bulk density 80 kg / m ³ = 32000, thickness 5 mm) and flame-retardant polyurethane foam (thickness 5 mm)
Is laminated and integrated using a phenol resin and an acrylic pressure-sensitive adhesive latex (coating amount: 50 g / m ² ) to a thickness of 10 mm.
Sound absorbing material was obtained.

The sound absorbing performance of the obtained sound absorbing material was 10
At 00 Hz and 2000 Hz, the sound absorption coefficient was 30
% And 80%, and had excellent sound absorbing performance.

[0030]

Example 2 In Example 1, the basis weight (g / g) was changed by changing the basis weight of the oxidized fiber web and the number of needle punches.
m ² ) × bulk density (kg / m ³ ) 7500, 8100,
Various needle-punched nonwoven fabrics of 13400 and 150,000 were obtained, and a sound absorbing material was produced in the same manner as in Example 1.

The sound absorbing performance of the obtained sound absorbing material was determined based on the basis weight (g / g).
When m ² ) × bulk density (kg / m ³ ) is 8000 or more, excellent sound absorbing performance was obtained as in Example 1, but 750.
At 0, the sound absorption rates were 15% and 25%, respectively, and the sound absorption performance was poor. .

[0032]

Example 3 A sound absorbing material was produced in the same manner as in Example 1 except that a glass wool having a thickness of 5 mm was used instead of the flame-retardant polyurethane foam (5 mm in thickness). The sound absorbing performance of the obtained sound absorbing material is 1000 Hz in frequency.
And 2000 Hz, the sound absorption coefficient was 50% and 8%, respectively.
0%, indicating excellent sound absorbing performance.

[0033]

Comparative Example 1 The nonwoven fabric (10 mm thick) obtained by laminating two needle-punched nonwoven fabrics of oxidized fiber used in Example 1 had a sound absorption coefficient of 15% at a frequency of 1000 Hz and 2000 Hz, respectively. And 40
%, And the sound absorbing performance was inferior.

[0034]

Comparative Example 2 The sound absorbing performance of the flame retardant polyurethane foam used in Example 1 having a thickness of 10 mm was 10
At 00 Hz and 2000 Hz, the sound absorption coefficient was 10
% And 20%, and the sound absorbing performance was inferior.

[0035]

Comparative Example 3 The glass wool used in Example 3 having a thickness of 1
The sound-absorbing performance of the 0 mm type is 1000 Hz and 2 Hz.
At 000 Hz, the sound absorption rates were 15% and 28%, respectively, and the sound absorption performance was poor.

[0036]

The sound absorbing material of the present invention has excellent sound absorbing performance and flame resistance.

 ────────────────────────────────────────────────── ─── Continued on the front page F-term (reference) 2E001 DF04 JA11 JA13 JA21 JA22 JA24 JA25 JA26 JA27 JD01 JD02 JD04 JD08 4F100 AA00B AK01B AK25 AK33 AK51 BA02 DG01A DG01B DG15A DJ01B EC09 GB07 JA13AJJ07A03A03 JJ01A03 CA05 CB05 CC10 5D061 AA06 AA12 AA23 BB21

Claims (1)

[Claims] 1. A sound-absorbing material in which a non-woven fabric made of flame-resistant fiber and a base made of inorganic fiber and / or polymer compound are laminated and integrated, wherein the non-woven fabric satisfies the following formula: A sound absorbing material characterized by the following. Bulk density (kg / m ³ ) × weight (g / m ² ) = 8000
200,000