JPH08160969A - Sound absorbing device - Google Patents

Abstract

PURPOSE: To provide a sound absorbing device capable of additionally improving a sound absorbing effect to noises. CONSTITUTION: This sound absorbing device has two sheets of acoustic wave absorbers 100A, 100B laminated via a urethane foam 20. These sound wave absorbers 100A, 100B have a pair of electrode plates, not shown in Fig., respectively housing electrosensitive type sound wave absorption controlling fluid compsns. A pair of these electrode plates are provided with a variable power source 60 which impresses voltage between these electrode plates and varies this voltage. The sound wave absorber 100A is provided with a microphone 22. A controller 25 which controls the intensity of the electric field impressed on the electrosensitive type sound wave absorption controlling fluid compsns. of the sound wave absorbers 100A, 100B by controlling the variable power source 60 in accordance with the output of this microphone 22 is connected between the microphone 22 and the variable power source 60.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a sound absorbing device suitable for use in soundproofing for blocking noise.

[0002]

2. Description of the Related Art In recent years, as the standard of living has improved, interest in noise has increased, and soundproofing has become an unavoidable theme regardless of industry. In particular, noise countermeasures mainly on highways such as impact on the environment along the road and noise countermeasures for karaoke,
It is a big social problem. A noise insulating panel made of a porous material such as porous concrete is used as the noise countermeasure. Since this sound insulation panel has a high sound absorption effect, it is effective as a noise countermeasure.

However, such a sound insulation panel has the following problems. That is, since the natural frequency is constant depending on the material, only the sound wave of the component that matches the natural frequency can be absorbed, and when changing the component of the sound wave to be absorbed, the It is necessary to replace the sound insulation panel with a different one. Therefore, the handling is complicated.

Therefore, recently, in order to solve the problem, the following sound absorbing device has been proposed. The sound absorbing device has an electric field array effect (hereinafter,
This is called the "EA effect". In addition, EA is Electric
Abbreviation for Alignment. (Hereinafter, referred to as "ENC fluid composition"). An electro-sensitive fluid absorption control fluid composition (hereinafter referred to as "ENC fluid composition") containing solid particles (hereinafter, referred to as "EA particles") having an) in an electrically insulating medium. What is ENC E
Abbreviation for "lectric noise-control". ) And an electric field applying means for applying an electric field to the ENC fluid composition and varying the applied voltage.

The viscosity of the ENC fluid composition provided in this sound absorbing device changes depending on the magnitude of the applied voltage. If the viscosity changes, the characteristic frequency also changes, so that the sound wave to be absorbed is changed. The frequency changes. Therefore,
According to this sound absorbing device, the frequency of the sound wave to be absorbed can be changed by increasing or decreasing the voltage by the voltage application adjusting means. Therefore, it is possible to solve the complexity of replacing the sound insulation panel with a different one in accordance with the frequency of the sound wave to be absorbed as in the case of using the conventional sound insulation panel.

[0006]

However, even such a sound absorbing device has the following problems when attempting to further improve the soundproof effect against noise. That is, the frequency of the sound wave of noise to be removed usually changes moment by moment. However, in the sound absorbing device as described above, after setting the frequency of the sound wave to be absorbed,
Since it only absorbs sound waves of that frequency, it is not always possible to exert a sufficient soundproof effect.

In view of the above circumstances, it is an object of the present invention to provide a sound absorbing device which can further improve the soundproof effect against noise.

[0008]

A sound absorbing device according to claim 1, wherein an ENC fluid composition containing EA particles having an EA effect in an electrically insulating medium, and a container for containing the ENC fluid composition. And an electric field applying means for applying an electric field to the ENC fluid composition, a detector for detecting a sound wave transmitted to the acoustic wave absorber, and an electric field applying means based on the output of the detector. Control and E of the sound absorber
It is characterized by comprising control means for controlling the strength of the electric field applied to the NC fluid composition.

A sound absorbing device according to a second aspect is the sound absorbing device according to the first aspect, characterized in that a plurality of the plate-shaped sound wave absorbers are stacked with a gap therebetween.

[0010]

According to the sound absorbing device of the present invention, when the detector detects the sound wave transmitted to the sound wave absorber, the control means is
Based on the output of the detector, the EN is applied by the electric field applying means.
Since it controls the strength of the electric field applied to the C-fluid composition,
Even when the frequency of the sound wave transmitted to the sound wave absorber changes, the strength of the electric field is changed in accordance with the change, and the ENC
The characteristic frequency of the fluid composition can be changed to a frequency that can effectively absorb the occasional sound waves.

The sound absorbing device according to a second aspect of the invention functions in the same manner as the sound absorbing device according to the first aspect of the invention, and the plurality of plate-shaped sound wave absorbers are overlapped with each other with a gap therebetween. The formed air layer can further enhance the sound absorbing effect.

[0012]

An embodiment of the present invention will be described below with reference to the drawings. FIG. 1 is a diagram showing an embodiment of a sound absorbing device of the present invention, and a sound absorbing device 200 has two sound wave absorbers 100A and 100B formed in a plate shape. The two acoustic wave absorbers 100A and 100B are laminated and adhered with the urethane home 20 formed in a plate shape being sandwiched therebetween.

As shown in FIG. 2, each of the sound wave absorbers 100A and 100B has a frame-shaped casing 15 whose sound absorbing surfaces 51 and 51 are open.
A pair of electrode plates 17 and 18 are installed inside the sound absorbing surface 51,
For example, PET (polyethylene terephthalate) films 19 and 19 which are arranged opposite to each other with a gap in a direction orthogonal to 51 and which are flexible against sound waves are provided on the sound absorbing surfaces 51 and 51 of the electrode plates 17 and 18, respectively. It is glued like. Electrode plates 17, 18 and PET films 19, 19
Is provided so as to close the opening of the casing 15, and the surfaces of the PET films 19, 19 are sound absorbing surfaces 51, 51. In addition, a pair of electrode plates 17, 1
The ENC fluid composition 10 is housed in each of the spaces 8 between them.

In the ENC fluid composition 10, as shown in FIG. 3, EA particles (electric field arranging particles) 2 which are solid particles are uniformly dispersed in an electrically insulating medium 1. This E
The A particle 2 is formed by a core body 3 made of an organic polymer compound and a surface layer 5 made of a particle 4 which is an electric field aligning inorganic substance (hereinafter referred to as “EA inorganic substance”) to form an inorganic / organic composite particle. are doing. In this specific example, the electrically insulating medium 1 is colorless and transparent silicone oil, the organic polymer compound forming the core body 3 of the inorganic / organic composite particles is polyacrylic ester, and the EA inorganic substance forming the surface layer 5 is used. The particles 4 are white titanium hydroxide that is an inorganic ion exchanger and an electric semiconductor inorganic substance. The color of the EA particles (inorganic / organic composite particles) is, for example, white. The proportion of the EA particles 2 contained in the electrically insulating medium 1 is, for example, 7.5% by weight.

Further, the sound wave absorbers 100A, 1 shown in FIG.
Between the pair of electrode plates 17 and 18 of 00B, a variable power source 60 that applies a voltage between the electrode plates 17 and 18 and adjusts the voltage variably is connected via an electric cable 63. The power supply 60 inputs the voltage adjustment signal S2 and variably adjusts the voltage based on the voltage adjustment signal S2.

A microphone mounting portion 21 which is a part of the casing 15 is provided below the sound absorbing surface 51 on the outer side of one of the sound wave absorbers 100A.
The microphone 22 is attached. The microphone 22 captures a sound wave and outputs a signal S1 according to the level of the frequency of the captured sound wave.

A control unit 25 is connected between the microphone 22 and the variable power source 60 via electric cables 64 and 65. The control unit 25 is captured by the microphone 22 from the microphone 22. The signal S1 corresponding to the frequency of the sound wave is input, and the variable power source 60 outputs the voltage adjustment signal S2 corresponding to the signal S1. Further, the control device 25 has data relating to the value of the voltage corresponding to the frequency of the sound wave, and the data is the voltage applied to the sound wave absorbers 100A and 100B by the variable power supply 60,
This data is used to set the optimum value for absorbing the sound wave captured by the microphone 22, and is data in which the higher the frequency of the sound wave, the higher the voltage corresponding to the sound wave. The control device 25 determines the voltage adjustment signal S2 to be output based on the data.

The sound absorbing device 200 has the above structure. The function of the sound absorbing device 200 will be described below as an example in which the sound absorbing device 200 is installed as a wall panel of a karaoke box. At that time, the microphone 2 is placed on the noise source side.
The sound wave absorber 100A provided with 2 is arranged to face each other.

First, when no noise is generated, that is, when the sound wave 11 is not input to the microphone 22, a voltage is applied between the pair of electrode plates 17 and 18 of the sound wave absorbers 100A and 100B shown in FIG. Not, ENC fluid composition 1
EA particles 2 having the EA effect in 0 are electrically insulating medium 1
It floats and disperses randomly inside. At this time, E
The sound absorbing effect of the NC fluid composition 10 is in a low state.

Next, noise is generated and the microphone 2 shown in FIG.
When the sound wave 11 is captured by 2, the microphone 22 outputs the signal S1 corresponding to the frequency of the sound wave 11 to the control device 25. The control device 25 outputs the voltage control signal S2 corresponding to the frequency of the sound wave 11 captured by the microphone 22 to the variable power supply 60 based on the signal S1. Then, the variable power source 60 applies a voltage to the pair of electrode plates 17 and 18 of each of the sound wave absorbers 100A and 100B based on the voltage control signal S2. Then, as shown in FIG.
Are aligned and linked in a chain to form a chain (particle chain) 6, and the chain 6 is aligned parallel to the electric field direction. In this state, when a sound wave (air vibration) 11 is incident on one of the electrode plates 17 as shown in FIG. 2, (a), (b),
The states of (c) and (d) occur sequentially, and as shown in FIG. 2 or FIG.
At the same time, it vibrates in the direction opposite to the other electrode plate 18,
Since the chain 6 itself has elasticity, the chain 6
Is pulled, as shown in FIG. 7 (b),
When the chain body 6 is compressed, for example, the chain body 6 is bent in a V shape to generate a repulsive force, and as shown in FIG. 7D, the chain body 6 is pulled when it is pulled. , The EA particles 2 facing each other attract each other to generate an attractive force. This enables ENC
The movement of the chain 6 in the fluid composition 10 causes viscous resistance, causing loss (dissipation) of the energy of the sound wave 11 shown in FIG.

That is, for the sound wave 11 incident on the electrode plate 17,
The ENC fluid composition 10 including the chain-like body 6 shown in FIG. 6 resonates with the electrode plate 17. The frequency of the sound wave 11 that vibrates the chain 6 is estimated to be a characteristic frequency of the chain 6 (a so-called natural frequency composed of balance between elasticity of the chain 6 and inertia of the electrode plate). When a sound wave 11 having a frequency matching the characteristic frequency is incident on the electrode plate 17, the chain 6 resonates and the sound wave 11
Absorbs. In addition, as shown in FIG. 2, the sound waves 12 of other frequencies are reflected.

Further, the attractive force (stress generated in the chain) acting between the EA particles 2 of the ENC fluid composition 10 shown in FIG. 5 provided inside the casing 15 of each sound absorbing device 200 shown in FIG. It increases / decreases as the voltage applied to the pair of electrode plates 17, 18 increases and decreases, and the elastic modulus and viscosity of the chain body 6 itself increase / decrease as the applied voltage increases / decreases.

The chain 6 of ENC fluid composition 10
When the elastic modulus and the viscosity of the ENC fluid composition increase or decrease, the characteristic frequency increases or decreases, so that the frequency of the sound wave 11 absorbed by the ENC fluid composition 10 changes.

Here, as described above, as shown in FIG. 2, the pair of electrode plates 1 of each of the sound wave absorbers 100A, 100B.
The voltage applied to 7 and 18 corresponds to the frequency of the sound wave 11 captured by the microphone 22 every moment, and the control device 2
5, the control device 25 controls the variable power source 6
When the voltage applied to each of the sound wave absorbers 100A and 100B is 0, the characteristic frequency of the ENC fluid composition 10 is 2
The voltage adjustment signal S is supplied to the variable power source 60 so that the value has an optimum frequency for absorbing the sound wave 11 captured by
2 is output and controlled.

Therefore, each of the sound wave absorbers 100A, 100B
The characteristic frequency of the chain-like body 6 of the ENC fluid composition 10 of No. 1 corresponds to the frequency of noise that changes from moment to moment. Then, the chain 6 in FIG. 5 resonates with the sound wave having the frequency of the noise and consumes the energy of the sound wave. Then, the sound waves 12 of other components are reflected as shown in FIG. Thereby, even if the frequency of the sound wave 11 of the noise changes, the noise can be effectively reduced. Therefore, a high soundproof effect against noise can be exhibited.

Further, in the sound absorbing device 200, since the two sound wave absorbers 100A and 100B are laminated via the urethane home 20, the sound wave absorbers 100A and 100B are two, and the space between them. The sound absorbing effect by the urethane home 20 itself can further enhance the sound absorbing effect by the air layer formed between the two sound wave absorbers 100A and 100B by the urethane home 20. Therefore, it is possible to further improve the soundproof effect against noise.

The characteristic frequency of the ENC fluid composition 10 of the sound absorbing device 200 includes the size of the EA particles (solid particles), the elastic force acting between the EA particles, the natural frequency of the electrode plates and the distance between the electrode plates. It changes with. In the present invention, since the spherical EA particles having a substantially uniform particle size are dispersed in the electrically insulating medium (without using irregular particles), the above-mentioned repulsive force and attractive force fluctuate under a constant voltage. No, and EA
The balance between the elastic force acting between particles and the inertial force of the electrode plate does not easily change. In the above-mentioned embodiment, the chain body is supposed to be bent in a "V" shape, but in addition to this, for example, an S-shape as shown in FIG. 8A, or (b) in FIG. It is considered that there is a case where the wire is bent into a W shape as shown in ().

Further, in the above embodiment, the phenomenon in which the EA particles (inorganic / organic composite particles) 2 form a row of chain-like bodies 6 and are arranged in parallel by the application of an electric field has been described. When the number of slabs exceeds several% by weight, 1
Instead of the chained bodies 6 in a row, the chained bodies 6 are joined to each other in a plurality of rows to form and arrange the column 119 as shown in FIG. In this column 119, the left and right chain-shaped EA particles 2 are staggered one by one and adjoin each other in a staggered manner.
With respect to this, the inventors of the present invention, as shown in (b) of FIG.
It is presumed that this is because it is more stable in terms of energy when the positive pole portion and the negative pole portion are alternately arranged adjacent to each other. Furthermore, although the ENC fluid composition is directly accommodated between the pair of electrode plates in the above-described embodiment, the present invention is not limited to this, and the porous body sufficiently impregnated with the ENC fluid composition is used as the pair of electrodes. It may be housed between the plates. In this case, the porous body preferably has open cells so as not to impair the EA effect.

The electrically insulating medium 1 of FIG. 3 used in the ENC fluid composition of the present invention is, for example, diphenyl chloride, butyl sebacate, aromatic polycarboxylic acid higher alcohol ester, halophenyl alkyl ether, trans oil. , Chlorinated paraffin, fluorine-based oil, silicone-based oil, fluorosilicone-based oil, etc., as long as they have high electrical insulation and electrical breakdown strength, are chemically stable, and can stably disperse EA particles. Fluids or mixtures of these can also be used. This electrically insulating medium 1 can be colored according to the purpose.
For coloring, it is preferable to use a type and amount of an oil-soluble dye or a dispersible dye that is soluble in the selected electrically insulating medium and does not impair its electrical properties. The electrically insulating medium 1 may further contain a dispersant, a surfactant, a viscosity modifier, an antioxidant, a stabilizer and the like.

The kinematic viscosity of this electrically insulating medium 1 is 1 cS.
It is preferably in the range of t to 30,000 cSt. When the kinematic viscosity is less than 1 cSt, the storage stability of the fluid composition is insufficient, and when the kinematic viscosity is more than 30,000 cSt, it becomes difficult to uniformly disperse the EA particles, and bubbles are entrained during the adjustment, and the bubbles are It is difficult to pull out, and it is difficult to handle, which is not preferable. From this viewpoint, the kinematic viscosity is preferably in the range of 10 cSt to 1000 cSt, particularly preferably in the range of 10 cSt to 100 cSt. Of course, the kinematic viscosity of the electrically insulating medium 1 changes with temperature, and this temperature effect can be suppressed by the applied voltage.

The EA particles 2 used in the present invention may be an element, an organic compound, an inorganic compound, or a mixture thereof as long as they are inorganic / organic composite particles having an EA effect.
Either material can be used. Examples thereof include particles of inorganic ion exchangers, metal oxides, silica gel, inorganic substances having electric semiconductors, carbon black, and particles having these as a surface layer. However, as shown in the above examples, the EA particles 2 are composed of the core body 3 made of an organic polymer compound and the EA inorganic particle 4
It is particularly preferable that the inorganic-organic composite particles are formed by the surface layer 5 consisting of. In this inorganic-organic composite particle, a surface layer 5 composed of particles 4 of EA inorganic material having a relatively high specific gravity is carried on a core body 3 which is an organic polymer compound having a relatively low specific gravity, and the specific gravity of the entire particle is changed to an electric value. It can be adjusted to approximate the insulating medium 1. Therefore, the ENC fluid composition obtained by dispersing this in the electrically insulating medium 1 has excellent storage stability.

Examples of the organic polymer compound that can be used as the core 3 of the EA particles (inorganic / organic composite particles) 2 include poly (meth) acrylic acid ester, (meth) acrylic acid ester-styrene copolymer, Polystyrene, polyethylene, polypropylene, nitrile rubber, butyl rubber, AB
S resin, nylon, polyvinyl butyrate, ionomer, ethylene-vinyl acetate copolymer, vinyl acetate resin,
One or a mixture of two or more such as a polycarbonate resin or a copolymer may be mentioned.

Particles 4 of EA inorganic material forming the surface layer 5
Although various compounds can be used, preferred examples include inorganic ion exchangers, silica gel, and electrically semiconducting inorganic substances. When these particles 4 are used to form the surface layer 5 on the core 3 made of an organic polymer compound, the obtained inorganic / organic composite particles become useful EA particles 2.

Examples of the above inorganic ion exchanger include (1)
Hydroxide of polyvalent metal, (2) hydrotalcites,
(3) Acid salt of polyvalent metal, (4) Hydroxyapatite, (5) Nasicon type compound, (6) Clay mineral, (7)
Mention may be made of potassium titanates, (8) heteropolyacid salts, and (9) insoluble ferrocyanide.

The respective inorganic ion exchangers will be described in detail below. (1) Hydroxide of polyvalent metal. These compounds are represented by the general formula MO _x (OH) _y (M is a polyvalent metal, x is a number of 0 or more, and y is a positive number), and examples thereof include titanium hydroxide and hydroxide. zirconium,
Examples include bismuth hydroxide, tin hydroxide, lead hydroxide, aluminum hydroxide, tantalum hydroxide, niobium hydroxide, molybdenum hydroxide, magnesium hydroxide, manganese hydroxide, and iron hydroxide. Here, for example, titanium hydroxide refers to hydrous titanium oxide (also known as metatitanic acid or β-titanic acid, Ti
It contains both O (OH) ₂ ) and titanium hydroxide (also known as orthotitanic acid or α-titanic acid, Ti (OH) ₄ ), and the same applies to other compounds.

(2) Hydrotalcites. These compounds have the general formula M ₁₃ Al ₆ (OH) ₄₃ (C
O) ₃ · 12H ₂ O (M is a divalent metal),
For example, the divalent metal M is Mg, Ca or Ni. (3) Acid salt of polyvalent metal. These are, for example, titanium phosphate, zirconium phosphate, tin phosphate, cerium phosphate, chromium phosphate, zirconium arsenate, titanium arsenate, tin arsenate, cerium arsenate, titanium antimonate, tin antimonate, tantalum antimonate. , Niobium antimonate, zirconium tungstate, titanium vanadate, zirconium molybdate, titanium selenate, and tin molybdate.

(4) Hydroxyapatite. These are, for example, calcium apatite, lead apatite,
Examples include strontium apatite and cadmium apatite. (5) Nasicon type compound. These include, for example, (H ₃ O) Zr ₂ (PO ₄ ) ₃ but in the present invention, a Nasicon type compound in which H ₃ O is replaced with Na can also be used. (6) Clay mineral. These are, for example, montmorillonite, sepiolite, bentonite and the like, with sepiolite being particularly preferred.

(7) Potassium titanates. These general formula _{aK 2 O · bTiO 2 · nH} 2 O (a 0
<A is a positive number that satisfies a ≦ 1, b is a positive number that satisfies 1 ≦ b ≦ 6, and n is a positive number), for example, K ₂ ·
TiO ₂ · 2H ₂ O, K ₂ O · 2TiO ₂ · 2H ₂ O, 0.
5K ₂ O ・ TiO ₂・ 2H ₂ O, and K ₂ O ・ 2.5TiO
₂ · 2H ₂ O, and the like. In addition, among the above compounds, a compound in which a or b is not an integer is easily synthesized by subjecting a compound in which a or b is an appropriate integer to an acid treatment and replacing K with H.

(8) Heteropolyacid salt. These are represented by the general formula H ₃ AE ₁₂ O ₄₀ .nH ₂ O (A is phosphorus, arsenic, germanium, or silicon, E is molybdenum, tungsten, or vanadium, and n is a positive number), For example, ammonium molybdophosphate and ammonium tungstophosphate. (9) Insoluble ferrocyanide. These are compounds represented by the following general formula. M _b-pxa
A [E (CN) ₆ ] (M is an alkali metal or hydrogen ion, A is a heavy metal ion such as zinc, copper, nickel, cobalt, manganese, cadmium, iron (III) or titanium, E is iron (II), iron (III), cobalt (II) or the like, b is 4 or 3, a is a valence of A, and p is a positive number of 0 to b / a.) These include, for example, Cs. Insoluble ferrocyanine compounds such as ₂ Zn [Fe (CN) ₆ ] and K ₂ Co [Fe (CN) ₆ ] are included.

The inorganic ion exchangers (1) to (6) each have an OH group, and some or all of the ions present at the ion exchange sites of these inorganic ion exchangers are different ions. Those substituted with (hereinafter, referred to as a substitutional inorganic ion exchanger) are also included in the inorganic ion exchanger of the present invention. That, R-M ¹ inorganic ion exchanger described above (M ¹ represents an ion species of the ion exchange sites) is expressed as a part or all of M ¹ in the R-M ^1, the ion exchange reaction below A substituted inorganic ion exchanger in which an ionic species M ² different from M ¹ is substituted by
It is an inorganic ion exchanger in the present invention. xR−M ¹ + yM ² → Rx− (M ² ) y + xM ¹ (where x and y represent the valences of the ion species M ² and M ¹ , respectively). M ¹ varies depending on the type of the inorganic ion exchanger having an OH group, but when the inorganic ion exchanger exhibits a cation exchange property, M ¹ is generally H ⁺ , and in this case, M ² is an alkali metal or an alkali. Any metal ion other than H ⁺ , such as earth metals, polyvalent typical metals, transition metals or rare earth metals. When the inorganic ion exchanger having an OH group exhibits anion exchange property, M ¹ is generally OH ^−.
Where M ² is, for example, I, Cl, SCN, N
Any of anions other than OH ⁻ such as O ₂ , Br, F, CH ₃ COO, SO ₄ or CrO ₄ and complex ions.

Further, regarding the inorganic ion exchanger which has once lost the OH group due to the high temperature heat treatment but becomes to have the OH group again by an operation such as immersion in water, the inorganic ion after the high temperature heat treatment is used. Exchangers and the like are also a kind of inorganic ion exchangers that can be used in the present invention, and specific examples thereof include a Nasicon type compound such as (H ₃ O) Zr ₂
(PO ₄₎ HZr ₂ obtained by heating ₃ (PO _{4) 3} and high-temperature heat treatment of hydrotalcite (500 to 70
Heat treated at 0 ° C.) and the like. These inorganic ion exchangers can be used not only in one kind but also in many kinds simultaneously as a surface layer. It is particularly preferable to use a hydroxide of a polyvalent metal and an acid salt of a polyvalent metal as the above-mentioned inorganic ion exchanger.

An example of an electrically semiconductive inorganic material that can be used as the surface layer 5 of the EA particles (inorganic / organic composite particles) 2 is a metal having an electric conductivity of 10 ³ to 10 ^-11 Ω ^-1 / cm at room temperature. Oxides, metal hydroxides, metal oxide hydroxides, inorganic ion exchangers, or metal-doped at least one of these, or at least any one of these regardless of the presence or absence of metal doping For example, those applied as an electric semiconductor layer on another support.

Examples of preferable electrically semiconductive inorganic substances are shown below. (A) Metal oxide: For example, SnO ₂ or amorphous titanium dioxide (manufactured by Idemitsu Petrochemical Co., Ltd.). (B) Metal hydroxide: For example, titanium hydroxide or niobium hydroxide. Here, titanium hydroxide means hydrous titanium oxide (manufactured by Ishihara Sangyo Co., Ltd.), metatitanic acid (also known as β-titanic acid,
TiO (OH) ₂ ) and orthotitanic acid (also known as α-titanic acid, Ti (OH) ₄ ) are included. (C) Metal oxide hydroxide: For example, FeO
(OH) (goethite) and the like can be mentioned. (D) Hydroxide of polyvalent metal: equivalent to inorganic ion exchanger (1). (E) Hydrotalcites: Inorganic ion exchanger (2)
Equivalent to (F) Acid salt of polyvalent metal: equivalent to the inorganic ion exchanger (3). (G) Hydroxyapatite: Inorganic ion exchanger (4)
Equivalent to (H) Nashicon type compound: equivalent to the inorganic ion exchanger (5). (I) Clay mineral: equivalent to the inorganic ion exchanger (6). (J) Potassium titanate: equivalent to the inorganic ion exchanger (7). (K) Heteropolyacid salt: equivalent to the inorganic ion exchanger (8). (L) Insoluble ferrocyanide: equivalent to inorganic ion exchanger (9). (M) Metal-doped EA inorganic substance: This is obtained by doping the ER inorganic substance with a metal such as antimony (Sb) in order to increase the electrical conductivity of the above-mentioned electric semiconductor inorganic substances (A) to (L). For example, antimony (S
b) Doping tin oxide (SnO ₂ ) and the like can be mentioned. (N) EA inorganic material applied as an electric semiconductor layer on another support: for example, titanium oxide, silica as a support,
Examples thereof include inorganic particles such as alumina and silica-alumina, or organic polymer particles such as polyethylene and polypropylene, to which antimony (Sb) -doped tin oxide (SnO ₂ ) is applied as an electric semiconductor layer. . The particles in which the EA inorganic substance is applied to the other support as described above can be regarded as the EA inorganic substance as a whole. These EA minerals are not only one type, but two
It is also possible to use types or more simultaneously as the surface layer.

The EA particles (inorganic / organic composite particles) 2 can be manufactured by various methods. For example, there is a method in which a particulate core body 3 made of an organic polymer compound and fine particulate particles 4 are transported by a jet stream and collided with each other to produce them. In this case, the fine particles of the particles 4 collide with the surface of the particulate core 3 at a high speed and are fixed to form the surface layer 5. Another example of the manufacturing method is a method in which the particulate core body 3 is suspended in a gas, and a solution of the particles 4 is atomized and sprayed on the surface. In this case, the surface layer 5 is formed by adhering the solution onto the surface of the core 3 and drying it.

A particularly preferred method for producing the EA particles (inorganic / organic composite particles) 2 is to form the surface layer 5 simultaneously with the core body 3. In this method, for example, when emulsion-polymerizing, suspension-polymerizing, or dispersion-polymerizing a monomer of an organic polymer compound forming the core body 3 in a polymerization medium, particles 4 which are EA inorganic particles in the form of fine particles, Alternatively, it is present in the polymerization medium. Water is preferred as the polymerization medium, but a mixture of water and a water-soluble organic solvent can also be used, and an organic poor solvent can also be used. According to this method, the monomers are polymerized in the polymerization medium to form the core particles 3, and at the same time, the fine particle EA inorganic particles 4 are layered on the surface of the core 3 to cover the core particles 3. The surface layer 5 is formed.

When EA particles (inorganic / organic composite particles) are produced by emulsion polymerization or suspension polymerization, the EA inorganic particles 4 are combined by combining the hydrophobic property of the monomer and the hydrophilic property of the EA inorganic substance. Can be attached to the surface of the core body 3. According to the method of simultaneously forming the core body 3 and the surface layer 5, the EA inorganic particles 4 are densely and firmly adhered to the surface of the core body 3 made of an organic polymer compound, and the EA particles (inorganic / organic composite) Particles 2) are formed.

The shape of the EA particles 2 used in the present invention does not necessarily have to be spherical, but when the particulate core 3 is produced by the controlled emulsion / suspension polymerization method, the EA particles obtained are obtained. The shape of the particles 2 is almost spherical. EA
The particle size of the particles 2 is not particularly limited, but is 0.1
The thickness is preferably in the range of μm to 500 μm, particularly 5 μm to 200 μm. Fine particle EA at this time
The particle size of the inorganic particles 4 is not particularly limited, but is preferably 0.005 μm to 100 μm, and more preferably 0.01 μm to 10 μm.

In the EA particles (inorganic / organic composite particles) 2, the particles 4 and the core 3 which are the EA inorganic substance forming the surface layer 5 are formed.
The weight ratio of the organic polymer compound forming the is not particularly limited, but in order to obtain an ENC fluid composition having high storage stability, the EA inorganic particles 4 and the organic polymer compound core 3 are used. 1% by weight of particles 4 to 6% of the total weight
It is preferably in the range of 0% by weight, particularly preferably in the range of 4% by weight to 30% by weight. If the proportion of the core 3 is less than 1% by weight, the EA characteristics of the obtained EA particles 2 will be insufficient, and if it exceeds 60% by weight, the specific gravity of the EA2 particles will be excessive and the storage stability may be impaired. There is. Further, the ENC fluid composition of the present invention can be produced by uniformly stirring and mixing the above-mentioned EA particles 2 together with a dispersant and other components in an electrically insulating medium. As the stirrer, any stirrer normally used for dispersing solid particles in a liquid dispersion medium can be used. In an electrically insulating medium 1
The content of the EA particles 2 in is not particularly limited, but is preferably 0.5 to 75% by weight, and particularly preferably 5 to 50% by weight. If the content is less than 1%, a sufficient EA effect cannot be obtained, and if the content is 75% or more, the initial viscosity of the ENC fluid composition when a voltage is not applied becomes too large, which makes it difficult to use.

The EA particles 2 produced by the above various methods, particularly the method of simultaneously forming the core 3 and the surface layer 5,
The surface layer 5 is wholly or partly covered with a thin film of an organic polymer substance, a dispersant, an emulsifier or other additive substances used in the manufacturing process, and the electric field arrangement effect as electric field arrangement particles is not sufficiently exhibited. There are cases. This thin film of inert material can be easily removed by polishing the surface of the particles. Therefore, when the core body 3 and the surface layer 5 are simultaneously formed, it is preferable to polish the surfaces thereof.

The polishing of the particle surface can be carried out by various methods. For example, EA, which is an inorganic / organic composite particle
The method can be performed by dispersing the particles 2 in a dispersion medium such as water and stirring this. At this time, a method of mixing an abrasive such as sand particles or balls into the dispersion medium and stirring with the EA particles 2, a method of stirring with a grinding wheel, or the like can be used. For example, it is also possible to dry-stir without using a dispersion medium, using the EA particles 2 and the above-mentioned abrasive or grinding stone.

A more preferable polishing method is a method in which the EA particles 2 are agitated by a jet stream or the like. This is a method of polishing particles by violently colliding with each other in a gas phase, and is a preferable method in that the polished particles can be easily separated by classification without the need for another abrasive. In the above jet stream agitation, it is necessary to select polishing conditions depending on the type of equipment used, the agitation speed, the material of the EA particles 2, etc., but generally 60
It is preferable to perform jet stream stirring at a stirring speed of 00 rpm for about 0.5 min to 15 min.

The ENC fluid composition of the present invention has the above EA
The particles 2 can be produced by uniformly stirring and mixing them in the electrically insulating medium 1 together with other components such as a dispersant, if necessary. As the stirrer, any stirrer normally used for dispersing solid particles in a liquid dispersion medium can be used.

Although the PET (polyethylene terephthalate) film 19 is used in the above-mentioned examples, various plastic films such as PVC (vinyl chloride) film, nylon film, polyethylene film, polypropylene film, acrylic film, etc. may be used instead. Etc. may be used.

Further, in the above embodiment, the sound absorbing device 2
The case where 00 is used as a wall panel has been described,
It may be used as a sound absorbing means mounted on a floor panel, a ceiling panel, or a device that generates noise.

Further, in the above embodiment, two sound wave absorbers 100A and 100B are provided through the urethane home 20, but if there is at least one sound wave absorber 100A and 100B, the same effect as described above is exhibited. You can do it.

In the above embodiment, the microphone 22 is used as a detector for detecting sound waves, but other vibration sensor may be used.

[0057]

According to the sound absorbing device of the first aspect, even when the frequency of the sound wave transmitted to the sound wave absorber changes,
By following the change, the electric field strength can be changed to change the characteristic frequency of the ENC fluid composition to a frequency that can effectively absorb the sound wave at that time. Therefore,
Since it is possible to effectively absorb noise even with noise whose frequency changes from moment to moment, it is possible to exert a high soundproof effect against noise.

According to the sound absorbing device of the second aspect, in addition to the above effect, the sound absorbing effect can be further enhanced by the air layer formed between the plurality of plate-shaped sound wave absorbers. . Therefore, it is possible to further improve the soundproof effect against noise.

[Brief description of drawings]

FIG. 1 is a diagram showing an embodiment of a sound absorbing device of the present invention.

2 is a cross-sectional view of the sound absorbing device of FIG. 1 cut in the direction of arrow A in FIG.

FIG. 3 is a cross-sectional view showing an example of the ENC fluid composition according to the present invention.

FIG. 4 is a cross-sectional view showing an aspect of the ENC fluid composition according to the present invention when the power is turned off.

FIG. 5 is a cross-sectional view showing an aspect of the ENC fluid composition according to the present invention when the power is turned on.

6 is a cross-sectional view showing a state where a sound wave is incident and the chain and one of the electrode plates resonate in the sound absorbing device of FIG.

FIG. 7 is a cross-sectional view showing in detail a state in which a sound wave is incident on the sound absorbing device of FIG. 2 and one of the electrode plates vibrates.

FIG. 8 is a diagram showing another example of the bending state of the chain in the sound absorbing device of FIG.

FIG. 9 is a view showing a column in which a plurality of chains are joined to each other in the sound absorbing device of FIG.

[Explanation of symbols]

1 ... Electrically insulating medium, 2 ... EA particles (solid particles), 10
Electrosensitivity type acoustic wave absorption control fluid composition, 15 ... Casing, 17 ... Electrode plate (electric field applying means), 18 ... Electrode plate (electric field applying means), 22 ... Microphone (detector), 25 ... Control device (control) Means), 60 ... Variable power source (electric field applying means), 100A, 100B ... Sound wave absorber, 200 ... Sound absorbing device.

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Moritaka Goto 1-5-1, Kiba, Koto-ku, Tokyo Fujikura Ltd. (72) Inventor Kenji Furuichi 1-1-5, Kiba, Koto-ku, Tokyo Shareholders Company Fujikura (72) Inventor Yasufumi Otsubo 9-21-1 Konakadai, Inage-ku, Chiba-shi, Chiba 206

Claims (2)

[Claims] 1. An electro-sensitive acoustic wave absorption controlling fluid composition comprising solid particles having an electric field array effect in an electrically insulating medium, and a container for accommodating the electro-sensitive acoustic wave absorption controlling fluid composition. A sound wave absorber, an electric field applying means for applying an electric field to the electro-sensitive type sound wave absorption control fluid composition, a detector for detecting a sound wave transmitted to the sound wave absorber, and an output of the detector. Control the electric field applying means based on
A sound absorbing device comprising control means for controlling the strength of an electric field applied to the electro-sensitive sound wave absorption control fluid composition of the sound wave absorber. 2. The sound absorbing device according to claim 1, wherein the plurality of plate-shaped sound wave absorbers are stacked with a gap therebetween.