JPH06136850A - Sound absorbing object and manufacture thereof - Google Patents

Abstract

PURPOSE:To promote weather resistance and, at the same time, to prevent a decline of sound absorption efficiency by adding water, rubber latex and fiber to a mixture of cement and lightweight aggregate, and curing it after the press molding. CONSTITUTION:Cement 100 pts.wt. is mixed with unit volume weight 0.2-0.8kg/l lightweight aggregate 300-800 pts.wt. having grain size 0.3-5.0mm. After that, water is added to cement lightweight aggregate mixture to mix. Then, the fibers having 2.0-20.0mm fiber length are mixed to cement-lightweight aggregate- water mixture so as to reach 0.5-5wt.% to the total weight of a sound absorptive object of a product. In addition, curing is made after the press molding of the admixture, so that the sound absorbing object having 0.5-5wt.% of a fiber content, 0.6-1.3 of specific gravity, more than 10% of a vertical incident sound absorption factor of center frequency 400Hz and more than 40% of a vertical incidentsound absorption factor of center frequency 100Hz is formed.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a sound absorber for use on walls of roads, railways and factories, as well as inner and outer walls of buildings, and a method of manufacturing the same.

[0002]

2. Description of the Related Art Glass wool mats and rock wool mats are widely used as sound absorbers provided on the walls of automobile roads, railways, and factories. However, these are obtained by binding a mat of inorganic fibers with a phenol resin or the like, and not only have poor sound absorption at low frequencies, but also easily absorb water such as rainwater, and the sound absorption rate is significantly reduced by water absorption. Therefore, it is greatly restricted when used outdoors. Also, since it is easy to absorb water such as rainwater, weather resistance,
In particular, it has little freeze-thaw resistance and is practically impossible to use in cold regions.

There are also known ceramic sound absorbing materials such as crushed ceramic wares which are bound with various binders using various binders, sound absorbing materials obtained by sintering metal particles, and the like. The peak characteristic of frequency characteristics is extremely strong, and sufficient performance as a sound absorber cannot be obtained. Also, when using no-fine concrete consisting of coarse aggregate and cement paste, which is mainly used as water-permeable concrete, as the sound absorbing material, the peak characteristic of the frequency characteristics is extremely strong like the above-mentioned ceramic sound absorbing material, and as a sound absorbing body. Sufficient performance cannot be obtained.

[0004]

SUMMARY OF THE INVENTION An object of the present invention is to overcome the weaknesses of the conventional sound absorbing body as described above and to improve the weather resistance, especially to prevent the sound absorbing performance from being deteriorated by absorbing water and to improve the freeze-thaw resistance. In addition, it is an object of the present invention to provide a sound absorbing body which has a broad sound absorbing characteristic and can deal with noise of a wide range of frequencies, and a manufacturing method thereof.

[0005]

In order to achieve such an object, the inventor of the present invention has earnestly studied and reached the present invention. That is, the gist of the present invention is (1) cement, lightweight aggregate, fiber length of 2.0 to 20.0 m
of 0.5 to 5% by weight, a specific gravity of 0.6 to 1.
3, normal incidence sound absorption coefficient of center frequency 400Hz is 10% or more and normal incidence sound absorption coefficient of center frequency 1000Hz is 4
0% or more sound absorber,

(2) Cement, lightweight aggregate, fiber length 2.0
The content of the fiber produced by kneading, molding and curing the fiber, rubber latex or resin emulsion of 20.0 mm and water is 0.5 to 5% by weight, and the content based on the solid content of the rubber latex or resin emulsion is 8%. Weight% or less, specific gravity 0.6 to 1.3, normal incidence sound absorption coefficient of center frequency 400 Hz is 10% or more and center frequency 1000 Hz
With a normal incidence sound absorption coefficient of 40% or more,

(3) 100 parts by volume of cement and lightweight aggregate 3
After mixing with 0 to 800 parts by volume, water is added to this mixture, and fibers having a fiber length of 2.0 to 20.0 mm are added and kneaded, followed by press molding or table vibrator molding, and then curing. A method of manufacturing the sound absorbing body according to the above (1), and

(4) 100 parts by volume of cement and lightweight aggregate 3
0 to 800 parts by volume are mixed, water and rubber latex or resin emulsion are added to this mixture, and fibers having a fiber length of 2.0 to 20.0 mm are further added and kneaded, followed by press molding or molding with a table vibrator. The method for producing a sound absorbing body according to (2) above, characterized in that the sound absorbing body is cured and then cured.

Further, a preferable sound absorbing body of the present invention is (5) the sound absorbing body according to the above (1) or (2) having a specific gravity of 0.6 to 1.0, and (6) a 28-day compressive strength. The sound absorbing body according to (1) or (2) above, which has a 10-day compression strength of 10 to 90 kg / cm ² , more preferably 15 to 50 kg / cm ² .

Further, the preferred production method of the present invention is (7) using a lightweight aggregate having a unit volume weight of 0.2 to 0.8 kg / liter, more preferably a unit volume weight of 0.2 to 0.5 kg / liter. (8) Use a lightweight aggregate having a particle size of 0.3 to 5.0 mm, more preferably a lightweight aggregate having a particle size of 0.6 to 2.5 mm. (9) Water cement ratio (weight ratio) 26-45%,
And (10) The method for producing a sound absorbing body according to (3) or (4), wherein press molding or molding with a table vibrator is carried out at a molding pressure of 20 to 60 g / cm ² .

The present invention will be described in detail below. The cement used in the present invention is Portland cement, mixed cement, or special cement. Lightweight aggregates are obsidian, pine rock,
Pearlite obtained by crushing and expanding pearlite, etc.
Inorganic foams proposed in JP-A-1-197479, or lightweight foams obtained by firing and expanding expansive shale, expansive clay, calcined fly ash, etc., preferably 0.2-0.8 kg / liter in unit volume weight, Particle size 0.3-5.0
mm, more preferably unit volume weight 0.2 to 0.5 kg
/ Liter, and a lightweight aggregate having a particle size of 0.6 to 2.5 mm is used.

The rubber latex or resin emulsion used in the present invention is a synthetic rubber-based, acrylic acid ester-based or rubber asphalt-based rubber latex, or a vinyl acetate-based, acrylic acid ester-based or resin asphalt-based resin emulsion. . The solid content standard content of the rubber latex or resin emulsion in the sound absorbing body of the present invention is based on the total weight of cement, lightweight aggregate, fiber, rubber latex or resin emulsion, water and a mixture and / or additive described later. It is 8% by weight or less. However, if the solid content of rubber latex or resin emulsion is less than 2% by weight based on the total weight of cement, lightweight aggregate, fiber, rubber latex or resin emulsion, water and admixture and / or additives. Melting resistance is not sufficient. Similarly, when the solid content standard content of the rubber latex or resin emulsion exceeds 8% by weight, the sound absorption coefficient decreases.

As the fibers, inorganic fibers such as glass fibers, carbon fibers, silicon nitride whiskers, tyranno fibers and basic magnesium sulfate fibers, or organic fibers such as hemp pulp, polypropylene and polyacrylonitrile are used.
The fiber used has a fiber length of 2.0 to 20.0 mm. The content of the fibers in the present invention includes cement, lightweight aggregate, fibers, rubber latex or resin emulsion (however, rubber latex or resin emulsion may not be contained. The same shall apply hereinafter), water and a mixture described below and / or It is 0.5 to 5% by weight based on the total weight of the additive.

When the fiber shape deviates from the above range, it does not contribute to the improvement of the sound absorption coefficient. The content of fiber is cement, lightweight aggregate, fiber, rubber latex or resin emulsion,
0.5 based on the total weight of water and admixtures and / or additives
If it is less than wt%, it does not contribute to the improvement of the sound absorption coefficient. If the content of fibers exceeds 5% by weight based on the total weight of cement, lightweight aggregate, fibers, rubber latex or resin emulsion, water and admixtures and / or additives, the strength of the sound absorbing body decreases.

The sound absorbing body of the present invention produced by the method described below using a predetermined amount of such raw materials has a specific gravity of 0.6.
~ 1.3, 28 days Compressive strength 10-90 kg / cm ² , normal incidence sound absorption coefficient of center frequency 400 Hz is 10% or more, and normal incidence sound absorption coefficient of center frequency 1000 Hz is 4%.
It is a novel sound absorber having a characteristic of 0% or more. The normal incidence sound absorption test was conducted in accordance with the method of JIS-A1405-1963 “Method for measuring vertical incidence sound absorption coefficient of building material by in-pipe method” using a specimen having a diameter of 10 cm and a thickness of 3 cm.

Next, the manufacturing method of the present invention will be described.
Cement and unit volume weight 0.2 to 0.8 kg / liter, particle size 0.3 to 5.0 mm, preferably unit volume weight 0.2 to 0.5 kg / liter, particle size 0.6 to 2.5 m
m lightweight aggregate is placed in a mixing vessel and mixed for about 20 seconds to 3 minutes. Mixing may be performed for 3 minutes or more, but there is no special effect. The mixing ratio of cement and lightweight aggregate is 300 to 800 parts by volume with respect to 100 parts by volume of cement.

Water or water and rubber latex or resin emulsion are added to the obtained cement-light weight aggregate mixture, and then the mixture is kneaded for 20 seconds to 3 minutes. In this case, the water cement ratio is 26-45%.

Next, glass fibers having a fiber length of 2.0 to 20.0 mm, carbon fibers, silicon nitride whiskers, tyranno fibers,
Inorganic fibers such as basic magnesium sulfate fibers or organic fibers such as hemp pulp, polypropylene, polyacrylonitrile, etc., into cement-lightweight aggregate-water kneaded material or cement-lightweight aggregate-rubber latex or resin emulsion-water kneaded material. , 0.5 to the total weight of the sound absorber of the product
Mix so as to be ~ 5% by weight. The mixing is performed for 40 seconds to 3 minutes so that the fibers are evenly dispersed.
Knead for seconds to 3 minutes.

The kneaded product thus obtained is spread in a mold, a weight is placed on it so that the molding pressure is 20 to 60 g / cm ² , and the mixture is compacted with a vibrator, or the weight and the vibrator are combined. Instead, use a press machine and perform press molding at a molding pressure of 20 to 60 g / cm ² for 30 times.
Do for 2 seconds to 2 minutes. After molding, normal temperature curing in a humid environment,
Underwater curing, air curing, or steam curing. Steam curing can improve the initial strength.

In the sound absorbing body of the present invention and the method for producing the same, a mixing material or an additive, such as fly ash, blast furnace slag, AE agent, etc., which is used in the production of ordinary cement hardened bodies within the range not impairing the object of the present invention, An AE water reducing agent, a high-performance water reducing agent, a foaming agent, a foaming agent, a setting / hardening accelerator, a quick-setting agent, and a waterproofing agent can be added. Generally, the amount is 10% or less of the total weight of the sound absorbing body.

[0021]

In the sound absorbing body of the present invention, the sound absorbing material and the air layer are vibrated by the incident sound wave, so that sound energy is converted into heat energy to exert a sound absorbing effect. Since a large number of the mixed fibers are dispersed in the lightweight aggregate and other voids, the same effect as when the voids are miniaturized can be obtained. Further, the surface area is remarkably increased due to the dispersion of the fibers themselves, and the sound damping effect is increased. Further, not only the sound absorption coefficient is improved as compared with the case where only the lightweight aggregate is contained without containing the fiber, but also the frequency characteristic of the sound absorption coefficient can be broadened. The addition of rubber latex or resin emulsion improves the strength and freeze-thaw resistance of the sound absorber.

[0022]

【Example】

Example 1 100 kg (about 67 liters) of early strength cement and 117 kg of lightweight aggregate having a particle size of 0.6 to 1.2 mm and a unit volume weight of 0.35 kg / liter were put in a mixing container and mixed for about 30 seconds to obtain Add 40 kg of water to the mixture and add about 30
Knead for 2 seconds. After that, 5.1 kg of hemp pulp having a fiber length of 3 mm and a specific gravity of 1.51 was added while kneading in about 60 seconds, and after kneading for about 60 seconds, the kneaded product was taken out of the kneading container, and steel of φ10 cm × 20 cm was prepared. It was placed in a columnar mold, and a weight to which a stress of 40 g / cm ² was applied was placed on the top, and a table vibrator was applied for about 1 minute for molding.
This molded product was cured in a humid environment to produce the sound absorbing body of the present invention. Table 1 shows the 28-day compressive strength and specific gravity of the sound absorber.

A test piece having a diameter of 10 cm and a thickness of 3 cm was prepared from a cylindrical sound absorber having a diameter of 10 cm × 20 cm, and a normal incidence sound absorption coefficient test was conducted. FIG. 1 shows the relationship between the center frequency of the sound absorber and the normal incident sound absorption coefficient. The 28-day compressive strength of the sound absorber was measured according to JIS-A1108-1976 "Concrete compression test method". Moreover, the normal incidence sound absorption test followed the method of JIS-A1405-1963 "Method for measuring normal incidence sound absorption coefficient of building materials by in-pipe method".

[0024]

[Table 1]

Example 2 Instead of adding 40 kg of water, an ethylene vinyl acetate copolymer emulsion (solid content 43.5% by weight, viscosity 150)
0-2000 cps. , Ube Kosan Co., Ltd., trade name U primer, the same applies below) 10 kg and water 29 on a solids basis.
A sound absorbing body was manufactured in the same manner as in Example 1 except that the amount of kg was added. Table 1 shows the 28-day compressive strength and specific gravity of the sound absorber. FIG. 1 shows the relationship between the center frequency of the sound absorber and the normal incident sound absorption coefficient.

Further, a test body having a diameter of 10 cm and a thickness of 3 cm was prepared from a cylindrical sound absorbing body of φ10 cm × 20 cm,
Using this test body, the deterioration degree when the freeze-thaw cycle in water of −20 ° C. to + 4 ° C. was repeated was visually examined. The results are shown in Table 2.

[0027]

[Table 2]

Example 3 Instead of adding 5.1 kg of hemp pulp, a fiber length of 13 m
m, specific gravity 2.7 chopped strand glass fiber 8.
A sound absorbing body was manufactured in the same manner as in Example 2 except that 9 kg was added. Table 1 shows the 28-day compressive strength and specific gravity of the sound absorber. FIG. 1 shows the relationship between the center frequency of the sound absorber and the normal incident sound absorption coefficient.

Example 4 Instead of adding 5.1 kg of hemp pulp, a fiber length of 5 mm,
A sound absorber was manufactured in the same manner as in Example 2 except that 3.1 kg of polypropylene fiber having a specific gravity of 0.9 was added. 28 of sound absorber
Table 1 shows the daily compressive strength and specific gravity. FIG. 1 shows the relationship between the center frequency of the sound absorber and the normal incident sound absorption coefficient.

Example 5 100 kg of early-strength cement (about 67 liters) and 117 kg of lightweight aggregate having a particle size of 1.2 to 2.5 mm and a unit volume weight of 0.25 kg / liter were put in a mixing container and mixed for about 30 seconds. Then, 10 kg of ethylene-vinyl acetate copolymer emulsion and 29 kg of water were added to the obtained mixture and kneaded for about 30 seconds. After that, fiber length 13m
4.9 kg of polypropylene having a specific gravity of 0.9 was added while kneading in about 60 seconds, and after further kneading for about 60 seconds, the kneaded product was taken out from the kneading container, and the diameter was 10 cm × 20 cm.
It was placed in a steel cylindrical mold of cm, a weight to which a stress of 40 g / cm ² was applied was placed on the upper part, and a table vibrator was applied for about 1 minute for molding. This molded product was cured in a humid environment to produce the sound absorbing body of the present invention.

The 28-day compressive strength of the sound absorbing body is 23 kg / cm.
² and the specific gravity was 0.91. FIG. 1 shows the relationship between the center frequency of the sound absorber and the normal incident sound absorption coefficient.

Comparative Example 1 A sound absorber was manufactured in the same manner as in Example 1 except that hemp pulp was not added, and its 28-day compressive strength and specific gravity were measured. The results are shown in Table 1. A freeze-thaw test was conducted in the same manner as in Example 2. The results are shown in Table 2.

Comparative Example 2 A sound absorbing body was produced in the same manner as in Example 2 except that hemp pulp was not added, and its 28-day compressive strength and specific gravity were measured. The results are shown in Table 1. A freeze-thaw test was conducted in the same manner as in Example 2. The results are shown in Table 2. FIG. 1 shows the relationship between the center frequency of the sound absorber and the normal incident sound absorption coefficient.

[0034]

EFFECTS OF THE INVENTION The sound absorbing body of the present invention is less likely to deteriorate in sound absorbing performance due to water absorption and has a broad sound absorbing characteristic, so that it can cope with noise in a wide range of frequencies. The sound absorbing body containing the rubber latex or the resin emulsion of the present invention is less likely to deteriorate in sound absorbing performance due to water absorption, and has a broad sound absorbing characteristic, so that it can cope with noise in a wide range of frequencies and at the same time has high freeze-thaw resistance. The method for manufacturing the sound absorbing body of the present invention,
Such a sound absorber can be manufactured in a suitable and simple manner.

[Brief description of drawings]

FIG. 1 is a graph showing the relationship between the center frequency and the normal incidence sound absorption coefficient of the sound absorbers obtained in Examples 1 to 5 and Comparative Example 2 of this specification.

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁵ Identification number Office reference number FI technical display location C04B 24/26 Z 28/02 E01F 8/00 8202-2D G10K 11/16 A 7406-5H

Claims (4)

[Claims] 1. Cement, lightweight aggregate, fiber length 2.
The content of fibers produced by kneading, molding and curing 0 to 20.0 mm fibers and water, 0.5 to 5% by weight, specific gravity of 0.6 to 1.3, and normal incidence sound absorption coefficient of center frequency 400 Hz are A sound absorber with a normal incidence sound absorption coefficient of 10% or more and a center frequency of 1000 Hz of 40% or more. 2. Cement, lightweight aggregate, fiber length 2.
The content of the fiber produced by kneading, molding and curing a fiber of 0 to 20.0 mm, rubber latex or resin emulsion and water is 0.5 to 5% by weight, and the content of the rubber latex or resin emulsion is based on the solid content. Is 8% by weight
Below, the specific gravity is 0.6 to 1.3, the normal incidence sound absorption coefficient at the center frequency of 400 Hz is 10% or more, and the center frequency is 1000H.
A sound absorber with a normal incidence sound absorption coefficient of z of 40% or more. 3. 100 parts by volume of cement and 300 to 800 parts by weight of lightweight aggregate are mixed, water is added to this mixture, and fibers having a fiber length of 2.0 to 20.0 mm are further added and kneaded, followed by pressing. The method for producing a sound absorbing body according to claim 1, wherein molding is performed or molding is performed by a table vibrator, and then curing is performed. 4. 100 parts by volume of cement and 300 to 800 parts by weight of lightweight aggregate are mixed, water and rubber latex or resin emulsion are added to this mixture, and further fibers having a fiber length of 2.0 to 20.0 mm are added. 3. The method for producing a sound absorbing body according to claim 2, wherein the mixture is kneaded by kneading, then press-molded or molded by a table vibrator, and then cured.