JPH09330086A - Sound absorbing material - Google Patents

Abstract

PROBLEM TO BE SOLVED: To reliably absorb low-frequency sound of less than a specific frequency by mixing an active component into a resin matrix which composes sound absorbing material. SOLUTION: Resin components constituting a resin matrix 11 is mixed with an active ingredient which can increase the amount of the dipole moment 12 arising in the resin matrix 11. For example, the moment of dipoles 12 generated in the matrix 11 is increased to an amount three or ten times larger than that at the time when sound energy, frequency and temperature condition are specified by being mixed with an active component. By this, energy consumption in the restoring action of dipoles 12 when sound energy is imparted is increased. Furthermore added with a sound absorbing effect due to friction on the surface of material, a sound absorption effect much more than the predicted one is caused and accordingly low-frequency sound below 1000Hz is reliably absorbed.

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to a vibration damping material, a sound absorbing film, a sound absorbing fiber (fiber, a strand), a sound absorbing foam, a sound absorbing paper, a sound absorbing molded body and the like used for applications such as asphalt roads (quiet roads). The present invention relates to a sound absorbing material used for a purpose.

[0002]

2. Description of the Related Art Conventionally, as sound absorbing materials, rock wool, glass wool, open-cell type polyurethane foam moldings,
Alternatively, those in which a film material is attached to the surface of these materials are known. In these sound absorbing materials, the sound is consumed as frictional heat when passing through while colliding with the surface of the fiber or the inside of the open cells, so that the attenuation is measured.

In these conventional sound absorbing materials, the sound absorbing property is enhanced by increasing the surface resistance on the fiber surface or in the open cells.

[0004]

However, these sound absorbing materials require a certain amount of thickness when attempting to secure sufficient sound absorbing properties. Further, in order to reliably absorb sound of low frequency such as 1000 Hz or less, it is necessary to increase the thickness of these sound absorbing materials, but in reality, there is a limit, and sufficient measures are taken for low frequency sound. It wasn't done.

As a result of earnest studies on the sound absorbing material, the present inventor has found that the amount of dipole moment in the resin matrix constituting the sound absorbing material has a deep relation to the sound absorbing property, and the amount of dipole moment in the resin matrix is large. It has been found that the sound absorption property of the sound absorbing material can be significantly improved by increasing the amount.

The present invention has been completed on the basis of the above-mentioned findings, and has an excellent sound absorbing property, and particularly 100
It is an object of the present invention to provide a sound absorbing material capable of reliably absorbing low frequency sound of 0 Hz or less.

[0007]

In order to achieve the above-mentioned object, the invention according to claim 1 mixes an active ingredient for increasing the dipole moment amount in the resin matrix, which constitutes the sound absorbing material. The sound absorbing material, which is characterized by being a thing, was made into the gist.

The invention according to claim 2 has as its gist a sound-absorbing material characterized in that the active ingredient is one or more selected from compounds containing a mercaptobenzothiazyl group.

The invention of claim 3 has as its gist a sound absorbing material characterized in that the active ingredient is one or more selected from compounds having a benzotriazole group.

The invention according to claim 4 has as its gist a sound absorbing material characterized in that the active ingredient is one or more selected from phthalic acid esters having the following structures.

Embedded image (In the formula, R is any one of a phenyl group, a cyclohexyl group, a cyclopentyl group, a cyclopentyl group, and a 4-methylcyclohexyl group, or any two of these groups.)

The invention of claim 5 has a frequency of 110 Hz.
The sound absorbing material is characterized in that the dielectric loss factor thereof is 50 or more.

[0012]

BEST MODE FOR CARRYING OUT THE INVENTION The sound absorbing material of the present invention will be described in detail below. The sound absorbing material of the present invention is a sound absorbing film,
It is a material that can be applied to applications such as sound absorbing fibers (fibers, strands), sound absorbing foams, sound absorbing papers, and sound absorbing molded bodies. This sound absorbing material is one in which an active component that increases the amount of dipole moment is mixed in a resin matrix that constitutes the sound absorbing material.

Examples of the resin component constituting the resin matrix include polyvinyl chloride, polyethylene, polypropylene, ethylene-vinyl acetate copolymer, polymethylmethacrylate, polyvinylidene fluoride, polyisoprene, polystyrene, styrene-butadiene-acrylonitrile copolymer. Polymers, styrene-acrylonitrile copolymers, acrylonitrile-butadiene rubber (NBR), styrene-butadiene rubber (SBR), butadiene rubber (BR), natural rubber (NR), isoprene rubber (IR) and other polymeric materials, etc. And the like. Among them, polyvinyl chloride is preferred because it has good moldability and is inexpensive.

The resin matrix composed of these resin components consumes as frictional heat when passing through while colliding with the fiber surface or the inside of open cells when sound energy is applied, and the attenuation is measured. It is designed to be used.

Further, when sound collides with the resin matrix, vibration is generated. At this time, the dipole 12 existing inside the resin matrix 11 is displaced as shown in FIG. Displacement of the dipole 12 means that each dipole 12 inside the resin matrix 11 rotates or the phase shifts.

It can be said that the arrangement state of the dipoles 12 inside the resin matrix 11 before the addition of sound energy as shown in FIG. 1 is in a stable state. However, as shown in FIG. 2, when the dipole 12 existing inside the resin matrix is displaced due to the energy being applied to the resin matrix by the collision of sound, the resin matrix 11
Each dipole 12 inside will be placed in an unstable state, and each dipole 12 will try to return to the stable state shown in FIG.

At this time, energy is consumed. It is considered that the sound absorbing effect is generated through the generation of frictional heat on the surface of the resin matrix, the displacement of the dipole inside the resin matrix, and the energy consumption due to the restoring action of the dipole.

When considering such a sound absorbing mechanism, the surface resistance per unit area of the resin matrix as in the conventional sound absorbing material and the amount of dipole moment inside the resin matrix 11 as shown in FIGS. 1 and 2. However, it is understood that they are greatly involved in sound absorption. According to the experiments conducted by the present inventors, the larger the amount of dipole moment inside the resin matrix 11, the higher the performance of absorbing the sound energy of the resin matrix 11 (sound absorption). I understand.

The amount of dipole moment in the above-mentioned resin component varies depending on the type of resin component.
Further, even if the same resin component is used for the resin matrix, the amount of dipole moment generated in the resin matrix changes depending on the temperature when the sound is applied and the frequency of the sound. The amount of dipole moment also changes depending on the amount of sound energy applied to the resin matrix. Therefore, it is desirable to select and use the resin component having the largest dipole moment amount in consideration of temperature, frequency, energy magnitude, etc. when applied as a sound absorbing material for a certain application.

However, in selecting the resin component constituting the resin matrix, not only the amount of dipole moment in the resin matrix, but also the handling property, moldability, and moldability depending on the application and usage of the sound absorbing material. It is desirable to consider availability, temperature performance (heat resistance and cold resistance), weather resistance, and price.

In the sound absorbing material of the present invention, an active component capable of dramatically increasing the dipole moment amount in the resin matrix is mixed with the resin component constituting the resin matrix. The active component is a component that dramatically increases the amount of dipole moment in the resin matrix.The active component itself has a large dipole moment amount, or the active component itself has a small dipole moment amount, but the active component itself has a small dipole moment amount. A component that can dramatically increase the amount of dipole moment in the resin matrix by blending the active component.

For example, the amount of the dipole moment generated in the resin matrix 11 under a predetermined temperature condition, frequency of sound, and magnitude of energy is shown in FIG. Under the same conditions, the amount will increase to 3 times or 10 times. Along with this, the energy consumption due to the restoration action of the dipole when the above-mentioned energy is added will also increase dramatically, and in addition to this, the sound absorption effect due to the friction of the material surface will be added, far exceeding the prediction. It is considered that the sound absorption effect will occur.

Examples of the active ingredient which brings about such effects are N, N-dicyclohexylbenzothiazyl-
2-sulfenamide (DCHBSA), 2-mercaptobenzothiazole (MBT), dibenzothiazyl sulfide (MBTS), N-cyclohexylbenzothiazyl-2-sulfenamide (CBS), N-tert-
Butylbenzothiazyl-2-sulfenamide (BB
S), a compound containing a mercaptobenzothiazyl group such as N-oxydiethylenebenzothiazyl-2-sulfenamide (OBS), N, N-diisopropylbenzothiazyl-2-sulfenamide (DPBS),

2- {2'-hydroxy-3 '-(3 ", 4", having benzotriazole having an azole group bonded to the benzene ring as a mother nucleus and having a phenyl group bonded thereto,
5 ", 6" tetrahydrophthalimidemethyl) -5'-
Methylphenyl} -benzotriazole (2HPMM
B), 2- {2'-hydroxy-5'-methylphenyl} -benzotriazole (2HMPB), 2- {2 '
-Hydroxy-3'-t-butyl-5'-methylphenyl} -5-chlorobenzotriazole (2HBMPC
B), 2- {2'-hydroxy-3 ', 5'-di-t
Compounds having a benzotriazole group, such as -butylphenyl} -5-chlorobenzotriazole (2HDBPCB);

Alternatively, one or more selected from phthalic acid esters having the following structures may be mentioned.

Embedded image (In the formula, R is any one of a phenyl group, a cyclohexyl group, a cyclopentyl group, a cyclopentyl group, and a 4-methylcyclohexyl group, or any two of these groups.)

The amount of dipole moment in the active component is
Like the amount of dipole moment in the resin matrix, it varies depending on the type of active ingredient. Further, even if the same active ingredient is used, the amount of dipole moment generated in the resin matrix changes depending on the temperature when the sound energy is applied. The amount of dipole moment also changes depending on the amount of sound energy applied to the resin matrix. For this reason, it is desirable to consider the temperature and the magnitude of energy when applied as a sound absorbing material for a certain application, and to select and use the active component having the largest dipole moment amount at that time.

In determining the active ingredient to be added to the resin matrix, the compatibility between the active ingredient and the resin component constituting the resin matrix, that is, the SP value is taken into consideration. good.

The sound absorbing material of the present invention is prepared by blending a resin component and an active component, and if necessary, a corrosion inhibitor or a dye, or by molding the blend into a film, a fiber or a block. It can be obtained by spinning. A conventionally known method can be used as a molding method or a spinning method when the above-mentioned resin component, active ingredient and the like are blended and this blend is molded or spun into a film, fiber or block.

As described above, the sound absorbing material in which the active ingredient is blended in the resin matrix has a dramatic increase in the amount of dipole moment in the resin matrix, and thus has an excellent performance of absorbing sound energy (sound absorption). The amount of the dipole moment in this sound absorbing material, though it is exerted, is expressed as the difference in the dielectric constant (ε ′) between AB shown in FIG. That is, the larger the difference in the dielectric constant (ε ′) between AB shown in FIG. 4 is, the larger the amount of the dipole moment is.

4 is a graph showing the relationship between the dielectric constant (ε ′) and the dielectric loss factor (ε ″). As shown in this graph, the dielectric constant (ε ′) and the dielectric loss factor (ε ′) A relation such as dielectric loss factor (ε ″) = dielectric constant (ε ′) × dielectric loss tangent (tan δ) is established with ε ″).

The present inventor has found through research on sound absorbing materials that the higher the dielectric loss factor (ε ″) here, the higher the energy absorption performance (sound absorption).

On the basis of this finding, the dielectric loss factor (ε ″) of the above-mentioned sound absorbing material was investigated, and it was found that the frequency was 110H.
It was found that when the dielectric loss factor in z is 50 or more, the sound absorbing material has excellent energy absorbing performance (sound absorbing property).

[0033]

EXAMPLES FIGS. 5 to 7 show a sound absorbing material, and FIG. 5 shows a case where 100 parts by weight of DCHBSA is added to vinyl chloride resin and 1 mm.
FIG. 6 shows a sound absorbing sheet 40 in which a sound absorbing short fiber 41 formed by spinning a vinyl chloride resin containing 100 parts by weight of DCHBSA is contained in the sheet. FIG. 7 shows DCHBSA 10
Open cell type polyurethane foam molding 5 with 0 parts by weight added
0.

FIG. 8 shows the sound absorbing sheet 30 of FIG.
Is disposed inside a sound absorbing material 60 made of glass fiber 61 which has been conventionally used. In this case, the thickness of the sound absorbing material 60 can be greatly reduced, and furthermore, the low frequency sound of 500 HZ or less, which cannot be absorbed by the conventional sound absorbing material, can be reliably captured and absorbed.

FIG. 9 shows the sound absorbing short fibers 41 contained in an open-cell type polyurethane foam molding. 10 and 11 show a paper 70 or a woven fabric 80 in which the sound absorbing short fibers 41 are formed or woven as a part of the constituent fibers. These have excellent sound absorption properties and are extremely useful as wall materials and floor materials.

Next, the sound absorbing properties (sound absorption coefficient) of the sound absorbing material in which the active ingredient was mixed in the resin matrix shown in Table 1 below and the sound absorbing material not blended were examined.

[0037]

The sound absorption coefficient of each of the above samples was measured by using a normal incidence sound absorption coefficient measuring device (specified in JIS NoA1405) manufactured by B & K. The result is shown in FIG.
(Sample 1), FIG. 13 (Sample 2), FIG. 14 (Sample 3), and FIG. 15 (Sample 4). Each sample had a size of φ29 and a thickness of 200 μm, and a 20 mm air layer was provided behind each sample.

From FIGS. 12 to 15, the sound absorption coefficient of the sample 4 made of only PVC shows a sound absorption coefficient of 0.1 to 0.3 in the range of 1000 HZ to 4000 HZ, and the sound absorption coefficient in the low frequency range of 1000 HZ or less is Well below 0.1,
It can be seen that the sound absorption and sound energy absorption are not sufficient. In addition, for Sample 3 containing no active ingredient, a maximum of about 0.5 between 1000 HZ and 2000 HZ.
The sound absorption coefficient is shown, and although the sound absorption coefficient is improved to some extent,
It can be seen that at 1000 HZ or less, sufficient sound absorption and sound energy absorption are not performed.

On the other hand, Samples 1 and 2 have about 40
It is noted that the sound absorption coefficient exceeds 0.3 in the range of 0 Hz to 1200 Hz, and the maximum value of the sound absorption coefficient of Sample 1 is higher than 0.9, and that of Sample 2 is higher than 0.8. It

When the mechanical tan δ in each sample shown in Table 1 and the sound absorption coefficients in FIGS. 12 to 15 are observed, it is understood that the larger the mechanical tan δ, the larger the sound absorption coefficient.

[0042]

In the sound absorbing material of the present invention, the active ingredient is mixed in the resin matrix that constitutes the sound absorbing material, and the amount of dipole moment that consumes sound energy in the resin matrix is dramatically increased. , The sound absorption performance (sound absorption) of the sound which is far superior to the prediction is exhibited. In particular, it has an advantage that low frequency sound of 1000 Hz or less can be reliably absorbed.

Further, in the case of a sound absorbing material having a dielectric loss factor of 50 or more at a frequency of 110 Hz, an excellent sound energy absorbing performance (sound absorbing property) which cannot be predicted from the conventional sound absorbing material is exhibited.

[Brief description of drawings]

FIG. 1 is a schematic diagram showing a dipole in a resin matrix.

FIG. 2 is a schematic diagram showing a state of dipoles in a resin matrix when vibrational energy is applied.

FIG. 3 is a schematic diagram showing a state of a dipole in a resin matrix when an active ingredient is blended.

FIG. 4 is a graph showing a relationship between a dielectric constant (ε ′) and a dielectric loss factor (ε ″) in a resin matrix.

FIG. 5 is a schematic diagram showing a sound absorbing film made of the sound absorbing material of the present invention.

FIG. 6 is a schematic diagram showing a sound absorbing sheet containing sound absorbing fibers made of the sound absorbing material of the present invention.

FIG. 7 is a schematic diagram showing a sound absorbing foamed molded product containing the sound absorbing material of the present invention.

FIG. 8 is a schematic diagram showing a state in which a sound absorbing sheet made of the sound absorbing material of the present invention is arranged inside the sound absorbing material.

FIG. 9 is a schematic diagram showing an open-cell type polyurethane foam molded product containing sound absorbing fibers made of the sound absorbing material of the present invention.

FIG. 10 is a schematic view showing a paper in which a sound absorbing fiber made of the sound absorbing material of the present invention is made as a part of constituent fibers.

FIG. 11 is a schematic diagram showing a woven fabric in which sound absorbing fibers made of the sound absorbing material of the present invention are woven as a part of constituent fibers.

FIG. 12 is a graph showing the sound absorption coefficient of Sample 4 at each frequency.

FIG. 13 is a graph showing the sound absorption coefficient of Sample 3 at each frequency.

FIG. 14 is a graph showing the sound absorption coefficient of Sample 2 at each frequency.

FIG. 15 is a graph showing the sound absorption coefficient of Sample 1 at each frequency.

[Explanation of symbols] 11 ... Resin matrix 12 ... Dipole

Claims (5)

[Claims] 1. A sound absorbing material, characterized in that a resin matrix constituting the sound absorbing material is blended with an active ingredient for increasing the amount of dipole moment in the resin matrix. 2. The sound absorbing material according to claim 1, wherein the active ingredient is one or more selected from compounds containing a mercaptobenzothiazyl group. 3. The sound absorbing material according to claim 1, wherein the active ingredient is one or more selected from compounds having a benzotriazole group. 4. The sound absorbing material according to claim 1, wherein the active ingredient is one or more selected from phthalic acid esters having the following structures. Embedded image (In the formula, R is any one of a phenyl group, a cyclohexyl group, a cyclopentyl group, a cyclopentyl group, and a 4-methylcyclohexyl group, or any two of these groups.) 5. The dielectric loss factor at a frequency of 110 Hz is 5
The sound absorbing material according to claim 1, 2, 3 or 4, wherein the sound absorbing material is 0 or more.