JPH08123443A - Sound absorbing device - Google Patents

Abstract

PURPOSE: To enhance a soundproof effect and acoustic characteristics to noises by dividing the interior of a casing, providing the respective spaces with a pair of electrode plates housing an electrosensitive (ENC) fluid compsns. for controlling sound wave absorption of in the spacings and providing the respective electrode plates with voltage impressing and regulating means. CONSTITUTION: Partition plates 14 are mounted in the casing 15 in such a manner that the interior of the casing is divided into four pieces of the spaces S1 to S4. Respectively a pair of the electrode plates are arranged to face each other at the respective spacings in the respective spaces S1 to S4. The ENC fluid compsns. are housed in a hermetically closed state between a pair of the electrode plates of the respective spaces S1 to S4 of the casing 1. The ENC fluid compsns. are formed by uniformly dispersing EA particles (electric field arranging type particles) which are solid particles in electircally insulatable media. Further, variable power sources 60A to 60D which impress voltages between the electrode plates and vary and regulate the voltages are connected between a pair of the electrode plates. The respectively different voltages are impressed via the electrode plates to the ENC fluid compsns.

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 and sound absorbing processing for improving acoustic characteristics.

[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 centering on highways, such as the impact on the roadside environment, have become a major social issue. A noise absorbing plate made of a porous material such as porous concrete is used as the noise countermeasure. Since this sound absorbing plate has a high sound absorbing effect, it is effective as a noise countermeasure. Moreover, since the sound absorbing plate has a sound absorbing effect, in addition to the noise countermeasure,
It is also highly effective in improving the acoustic characteristics of tunnels and underground spaces.

However, such a sound absorbing plate 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 absorbing plate 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 includes an electric field array effect (hereinafter, E
The electric alignment effect is abbreviated as “E
Solid particles having electric field-arranging particles (hereinafter referred to as "EA particles" for abbreviated form of electric field arrangement particles) in an electrically insulating medium. A fluid composition for controlling electro-acoustic sound wave absorption (hereinafter, referred to as Electric Noise-Co).
(abbreviation of "control fluid composition" is referred to as "ENC fluid composition"), and a pair of electrode plates are provided with voltage application adjusting means for applying a voltage 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, when using the conventional sound absorbing plate, it is possible to solve the complexity of replacing the sound absorbing plate with a different one according to the frequency of the sound wave to be absorbed.

[0006]

However, even such a sound absorbing device has the following problems when it is attempted to further improve the soundproof effect against noise or the acoustic characteristics of space. ing. That is, even in the case of noise,
Also in the case of sound, the frequency of the sound wave to be removed is not necessarily one. Therefore, in such a case, the sound absorbing device as described above can absorb the sound wave of one frequency but cannot absorb the sound wave of the other frequency. Cannot be improved.

In view of the above circumstances, it is an object of the present invention to provide a sound absorbing device capable of further improving the soundproof effect against noise or the acoustic characteristics of space.

[0008]

According to a first aspect of the present invention, there is provided a sound absorbing device having a casing whose sound absorbing surface side is open, and the casing is provided with a partition plate for dividing the interior of the casing into a plurality of spaces. In each of the spaces, a fluid composition for electro-sensitive acoustic wave absorption control, which comprises solid particles having an electric field array effect in an electrically insulating medium, is opposed to each other with a gap, and is provided in the gap. A pair of electrode plates accommodating the fluid composition for electro-sensitive sound wave absorption control is provided, and a voltage is applied to each of the pair of electrode plates to apply a voltage between the electrode plates and variably adjust the voltage. An adjusting means is provided.

[0009]

According to the sound absorbing device of the present invention, when different voltages are applied to the ENC fluid compositions provided in the respective spaces of the casing through the electrode plates by the respective voltage application adjusting means, the casing is The ENC fluid composition in each of the spaces can have different characteristic frequencies. Therefore, the sound absorbing device of the present invention acts so as to be able to simultaneously absorb sound waves of a plurality of frequencies.

[0010]

An embodiment of the present invention will be described below with reference to the drawings. As shown in FIG. 1, the sound absorbing device 100 of the present invention.
Has a box-shaped casing 15 whose sound absorbing surfaces 51A to 51D are open. Inside the casing 15, the cross-shaped partition plate 14 when viewed from the sound absorbing surfaces 51A to 51D side,
The casing 15 is mounted so as to divide the inside into four spaces S1 to S4.

In each of the spaces S1 to S4, as shown in FIG. 2, a pair of electrode plates 17A to 17D and 18A to 18A, respectively.
18D are arranged to face each other with a gap in a direction orthogonal to the sound absorbing surfaces 51A to 51D, and the sound absorbing surfaces 51A to 51D side electrode plates 17A to 17D are flexible against sound waves, for example PET (polyethylene terephthalate). Film 19
A to 19D are evenly adhered to each other. One electrode plate 17A to 17D and PET film 19A to 19D
Is provided so as to close the opening of the casing 15, and the surfaces of the PET films 19A to 19D are sound absorbing surfaces 51A to 51D. Also, casing 1
5, a pair of electrode plates 17A to 17D in the spaces S1 to S4,
Between 18A and 18D, ENC fluid composition 10
Are housed in a sealed state.

In the ENC fluid composition 10, as shown in FIG. 3, EA particles (field aligning 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.

As shown in FIG. 2, between the pair of electrode plates 17A to 17D and 18A to 18D, a voltage is applied between the electrode plates 17A to 17D and 18A to 18D and the voltage is variably adjusted. Adjustable power supply 60A-60D
Are connected via electric cables 63A to 63D as shown in FIG. Also, variable power sources 60A to 60D
Is a switch 61A for turning the voltage application on or off
~ 61D and dial 62 for variably adjusting the applied voltage
A to 62D.

Since the sound absorbing device 100 has the above-mentioned structure, first, the switch 61 of the variable power sources 60A to 60D is used.
When A to 61D is OFF, that is, when no voltage is applied between the pair of electrode plates 17A to 17D and 18A to 18D as shown in FIG. 4, the EA having the EA effect in the ENC fluid composition 10 is obtained. The particles 2 are randomly suspended and dispersed in the electrically insulating medium. At this time, the sound absorbing effect of the ENC fluid composition 10 is in a low state.

Next, the switches 61A to 61D of the variable power sources 60A to 60D are turned on to turn the pair of electrode plates 17A to 17A.
When a voltage is applied to D and 18A to 18D, the EA particles 2 are arranged and linked in a chain shape as shown in FIG. 5 to form a chain (particle chain).
6 are formed, and the chain-like bodies 6 are arranged in parallel with the electric field direction. In this state, one of the electrode plates 17A to 17D has a structure shown in FIG.
When a sound wave (air vibration) 11 is incident as shown in FIG. 7, the states of (a), (b), (c) and (d) of FIG. 7 occur sequentially, and as shown in FIG. This electrode plate 17
A to 17D vibrate in the opposite direction to the other electrode plates 18A to 18D together with the PET films 19A to 19D,
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, the sound wave 11 incident on the electrode plates 17A to 17D resonates between the ENC fluid composition 10 containing the chain-like body 6 shown in FIG. 6 and the electrode plates 17A to 17D. The sound wave frequency that gives vibration to the chain 6 is estimated to be a characteristic frequency of the chain 6 (a so-called natural frequency, which is a balance between elasticity of the chain 6 and inertia of the electrode plate). ), And when a sound wave having a frequency matching the characteristic frequency is incident on the electrode plates 17A to 17D, the chain-like body 6
Resonates and absorbs the sound wave 11. In addition, as shown in FIG. 2, the sound waves 12 of other frequencies are reflected.
Therefore, at this time, the sound absorbing effect of the ENC fluid composition 10 is high.

Next, the variable power sources 60A to 60A shown in FIG.
When the dials 62A to 62D of 60D are turned, the ENs shown in FIG. 5 provided in the spaces S1 to S4 of the casing 15 are shown.
The attractive force (stress generated in the chain) acting between the EA particles 2 of the C fluid composition 10 is a pair of electrode plates 17A to 17D, 18
It increases / decreases with an increase / decrease in the voltage applied to A to 18D, and the elastic modulus and viscosity of the chain 6 itself increase / decrease with an increase / decrease in the applied voltage.

The chain 6 of ENC fluid composition 10
When the elastic modulus and the viscosity of the ENC fluid are increased or decreased, the characteristic frequency is increased or decreased, so that the frequency of the sound wave absorbed by the ENC fluid composition 10 is changed.

Therefore, when the applied voltage is adjusted by the dials 62A to 62D of the variable power sources 60A to 60D, EN
The characteristic frequency of the chain 6 of the C-fluid composition 10 can be matched with the frequency of the component to be removed from the incident sound wave (air vibration) 11 shown in FIG. Then, the chain 6 in FIG. 5 resonates with the sound wave having the frequency of the component to be removed.
And consume the energy of that sound wave. Then, the sound waves 12 of other components are reflected as shown in FIG.

Therefore, the ENC fluid composition 10 provided in each of the spaces S1 to S4 of the casing 15 absorbs sound waves of different frequencies when different voltages are applied by the variable power sources 60A to 60D. It will be. That is, the sound absorbing device 100 of the present invention can simultaneously absorb sound waves of a plurality of frequencies.

Therefore, when the sound absorbing device 100 is used as a soundproof plate, four prominent frequencies are selected from among the frequencies of the sound waves constituting the noise, and each ENC fluid composition 10 is selected at the selected frequency. Dials 62A to 6 of the variable power sources 60A to 60D so as to match the characteristic frequencies of
By adjusting 2D, it is possible to improve the soundproofing effect against noise as compared with the conventional case in which only the sound wave of one frequency is absorbed.

Also, when used as a sound absorbing plate in a space such as a music hall, among sound waves of frequencies to be removed,
Select four prominent frequencies, and at the selected frequencies,
Dials 62A to 62D of the variable power sources 60A to 60D so that the characteristic frequencies of the ENC fluid compositions 10 are matched.
By adjusting, it is possible to improve the acoustic characteristics as compared with the conventional case in which only a sound wave of one frequency is absorbed.

The characteristic frequency of the sound absorbing device 100 changes depending on 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. 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. In addition, the balance between the elastic force acting between the EA 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 ().

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 particle 2 used in the present invention is an inorganic / organic composite particle having an EA effect, such as an element, an organic compound, an inorganic compound, or a mixture thereof.
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 which are the EA inorganic substance 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 at the same time as 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.

In the case of producing EA particles (inorganic / organic composite particles) 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 obtained is 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-mentioned 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.

In the above embodiment, the casing 1
Partition plate 14 so as to form four spaces S1 to S4 in 5
However, it is not necessary that the number is four, and it is needless to say that the number may be two, three, or five or more. Also in this case, the ENC fluid composition and the pair of electrode plates are provided in the respective spaces, and the variable power sources are provided in the pair of electrode plates.

[0050]

According to the sound absorbing device of the first aspect, since sound waves of a plurality of frequencies can be absorbed at the same time, the sound absorbing plate can be used as a sound insulating plate to further improve the sound insulating effect against noise. By using it as a sound absorbing plate in a space, it is possible to further improve the acoustic characteristics of the space.

[Brief description of drawings]

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

FIG. 2 is an enlarged cross-sectional view showing the inside of the casing of the sound absorbing device shown 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.

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

FIG. 7 is a cross-sectional view showing a state where a sound wave is incident on the sound absorbing device of the present invention 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 the present invention.

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

[Explanation of symbols]

2 ... EA particles (solid particles), 10 ... Electrosensitive acoustic wave absorption control fluid composition, 17A to 17D ... Electrode plate, 18A to
18D ... Electrode plate, 60A-60D ... Variable power supply (voltage application adjusting means), 100 ... Sound absorbing device, S1-S4 ... First-fourth spaces.

Continuation of the front page (51) Int.Cl. ⁶ Identification number Reference number within the agency FI Technical display location G10K 11/162 G10K 11/16 A (72) Inventor Moritaka Goto 1-5-1 Kiba, Koto-ku, Tokyo Stocks Within Fujikura (72) Inventor Kenji Furuichi 1-5-1, Kiba, Koto-ku, Tokyo Stock within Fujikura (72) Inventor Yasufumi Otsubo 9-21-1 Konakadai, Inage-ku, Chiba-shi, Chiba 206

Claims (1)

[Claims] 1. A casing having an open sound absorbing surface side is provided, the casing is provided with a partition plate that divides the interior of the casing into a plurality of spaces, and each of the spaces has an electric field array effect. An electro-sensitive acoustic wave absorption controlling fluid composition containing solid particles having an electrically insulating medium, and facing each other with a gap,
A pair of electrode plates accommodating the fluid composition for electro-sensitive acoustic wave absorption control is provided in the gap, and a voltage is applied between the electrode plates and the voltage is variably adjusted to each of the pair of electrode plates. A sound absorbing device, characterized in that a voltage application adjusting means is provided.