JP2001282252A - Sound absorbing material - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a sound absorbing material which is excellent in sound absorption qualities, retains a sound absorption effect for a long period without clogging, facilitates fabrication and is light in weight. SOLUTION: The sound absorbing material is molded by kneading 75 to 85 wt.% foam of 1.2 to 2.5 mm in grain size and 25 to 25 wt.% asphalt of 60 to 90 (25 deg.C and 1/10 mm) in needle penetration and 80 to 100 deg.C in softening point and pressing the mixture to specific gravity of 0.40 to 0.60 and therefore, the weight is reduced, the workability is improved, the fabricatability is enhanced and the sound absorbing effect excellent for a long period may be obtained without clogging.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a sound absorbing material that absorbs noise from roads, railways, factories, and the like.

[0002]

2. Description of the Related Art Sound absorbing materials provided around railway tracks or highways are required to be excellent in water resistance and weather resistance because they are installed outdoors. As a sound-absorbing material that has weather resistance, has non-combustibility, and is outdoors, as a sound-absorbing material with a void formed by molding an inorganic foam with cement.
JP-A-8-333819, JP-A-11-199299
No. is disclosed.

[0003]

However, those made of cement have a drawback that the voids are clogged with dust and the sound absorbing effect is reduced. In addition, workability is inferior due to the weight. On the other hand, sound-absorbing materials used around the machinery and equipment in factories need to be cut and installed as appropriate according to the shape of the machine, and those with excellent workability are required, but cement products are inferior in workability. .

[0004] It is an object of the present invention to provide a light-weight sound absorbing material which is excellent in sound absorbing property, does not deteriorate the sound absorbing effect for a long time without clogging, is easy to process, and is lightweight.

[0005]

A sound absorbing material obtained by kneading a foam and asphalt and pressing the mixture to have a specific gravity of 0.40 to 0.60 without clogging and having a long-term sound absorbing effect. Can be It has a foam as a main component and a specific gravity of 0.40-0.
Workability was improved because the weight was reduced to 60. In addition, an inorganic foam was used to reduce costs and enhance workability, and a portion other than the sound absorbing surface was covered with a resin to prevent the foam from peeling off.

Specifically, 75-85% by weight of a glass foam having a particle size of 1.2-2.5 mm and asphalt 25-15%
% By weight and kneaded and pressed to obtain a specific gravity of 0.40 to 0.1%.
The sound absorbing material is set to 60. Asphalt is
Penetration 60-90 (25 ° C, 1 / 10mm), softening point 8
0-100 ° C.

[0007]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Foams having hollow portions such as glass foams, silica foams, carbon foams and plastic foams, among which inorganic foams mainly composed of glass such as foamed glass beads, are used. Is preferable because of low water absorption. Fired and foamed glass recycled products can be manufactured at low cost. The particle size of the foam is 1.2 to 2.5 mm. When the particle size is smaller than 1.2 mm, the density increases, so that the sound absorption coefficient decreases. When the particle size is larger than 2.5 mm, the sound absorption coefficient increases only in a specific frequency region, and the sound absorption effect decreases over the entire frequency. .

Asphalt has a penetration of 60 to 90 (25
(1 ° C., 1/10 mm) and a softening point of 80 to 100 ° C. can be prevented from having a small temperature dependency and cracking occurring at low temperature in winter and flowing at high temperature in summer. In addition, toughness 20.0 Nm or more, tenacity 1
Those having a value of 5.0 Nm or more are preferable. To the asphalt, a thermoplastic elastomer, a rubber, and a cross-linking agent are added as needed to adjust properties of the asphalt such as viscoelasticity and strength.

The thermoplastic elastomer is, for example, a styrene-butadiene-styrene block copolymer (SB)
S), styrene-isoprene-styrene block copolymer (SIS), styrene-ethylene-butylene-styrene block copolymer (SEBS), styrene-ethylene-propylene-styrene block copolymer (SE)
PS) and the like.

As the rubber, nitrile rubber (NBR),
Styrene butadiene rubber (SBR), isoprene rubber (IR), butadiene rubber (BR), chloroprene rubber (CR), ethylene propylene rubber (EPR) and the like can be mentioned, among which styrene butadiene rubber (SBR) is preferable. .

Crosslinking agents include sulfur, dithiodimorpholine,
Examples include disulfide compounds such as thiuram disulfide, peroxides, quinone dioximes and the like.

The blending ratio of the foam and the asphalt is 75 to 85% by weight of the foam and 25 to 15% by weight of the asphalt.
In particular, 80% by weight of foam and 20% by weight of asphalt are particularly preferable. 500 when asphalt exceeds 25% by weight
The sound absorption coefficient at -800 Hz increases, but when it exceeds 800 Hz, the sound absorption coefficient decreases (see FIG. 4). If the asphalt is less than 15% by weight, the bonding of the foam is weakened, which is not preferable.

The above composition is pressed and molded to a specific gravity of 0.40 to 0.60 to obtain a sound absorbing material. If the specific gravity is less than 0.40, both strength and sound absorption are inferior,
If it exceeds 0.60, the sound absorption coefficient decreases.

The production method is as follows: 75 to 85% by weight of a foam having a particle size of 1.2 to 2.5 mm and a penetration of 60 to 90 (at 25 ° C., 1
/ 10 mm), asphalt 2 having a softening point of 80 to 100 ° C.
5 to 15% by weight is melt-kneaded with a mixer. At this time, a thermoplastic elastomer, rubber, and a crosslinking agent are added as required. After casting, press to make specific gravity 0.40 to 0.60
And cooled to obtain a sound absorbing material. The sound-absorbing material is reinforced by covering the side surface, the end surface or the back surface with a resin according to the application. Acrylic resin, urethane resin,
A coating agent of a vinyl paint can be used.

When used on a railroad track, a sound absorbing material is installed between sleepers under the track. At this time, the surface other than the upper surface serving as the sound absorbing surface is coated with acrylic emulsion. When used as a soundproof wall of a highway, the sound absorbing material is inserted and fixed to a rustproof H-shaped steel column or the like, or is fixed directly to a wall surface of concrete or the like. Also in this case, the parts other than the sound absorbing surface are reinforced by applying and coating with an acrylic emulsion.

(1) Sound absorption coefficient depending on particle size of foam Inorganic foam (trade name: G light, manufactured by Crystal Clay Co., Ltd.) and asphalt (trade name: Drainage ECO, manufactured by Showa Shell Sekiyu KK) shown in FIG. ) In a mixing ratio shown in FIG. 2 with a mixer (160 ° C., 5 minutes)
Pour into a 200 mm x 200 mm x 50 mm formwork,
It was press molded to a specific gravity of 0.55. Thereafter, the sample was naturally cooled for 24 hours, demolded, and subjected to sample No. 1-4 were obtained. The sound absorption coefficient of the inorganic foam and the asphalt was examined, and the results are shown in FIG. Sample No. 1 and No. 3 and sample no. 2 and N
o. Compared with No. 4, the asphalt amount is constant, and when the particle size is changed, the particle size is 1.2 to 2.5 mm,
It can be seen that the sound absorption coefficient is superior to that of 2.5 to 3.0 mm. In addition, the measurement of the sound absorption coefficient is based on JIS A 140
5 based.

(2) Sound Absorption Coefficient According to Asphalt Amount Using an inorganic foam (trade name: G-light No. 1, manufactured by Crystal Clay Co., Ltd.) shown in FIG.
The sound absorption coefficient was measured while changing to 5, 20, and 30% by weight, and the results are shown in FIG. If the asphalt is 30% by weight,
It can be seen that although excellent at low frequencies, the sound absorption coefficient is reduced as a whole.

[0018]

EXAMPLE Example 80% by weight of an inorganic foam (trade name: G light No. 1, manufactured by Crystal Clay Co., Ltd.) and asphalt (trade name: Drainage ECO, manufactured by Showa Shell Sekiyu KK) 2 shown in FIG.
0% by weight was stirred and mixed with a mixer (160 ° C., 5 minutes), poured into a 200 mm × 200 mm × 50 mm formwork, and press-molded to a specific gravity of 0.50. Then 2
After natural cooling for 4 hours, after removing the mold, an acrylic emulsion was applied and coated on the side surface to obtain a sound absorbing material. JIS A 140
5 was measured, and the results are shown in FIG.

[0019]

The sound absorbing material of the present invention is excellent in sound absorbing properties and can prevent clogging, so that the sound absorbing effect is maintained for a long time. Since it is an inorganic foam and has a specific gravity of 0.40 to 0.60, it is lightweight and has improved workability. Since the foam is a main component, it can be easily cut and has high on-site workability. The manufacturing process is simple, and if a fired body of recycled glass is used for the foam, it can be manufactured at low cost. Since the side surface or the end surface is covered with the resin, the foam does not separate and the strength is increased.

The present invention can be used for soundproof walls of roads, factories, waste treatment facilities, electric power facilities, machine rooms, and the like. By laying under railroad tracks between railroad sleepers, it is possible to prevent noise when the train is running.

[Brief description of the drawings]

Fig. 1 Properties of inorganic foam

Fig. 2 Mixing of inorganic foam and asphalt

FIG. 3 is a diagram showing a sound absorption coefficient depending on a particle size of an inorganic foam.

FIG. 4 is a diagram showing a sound absorption coefficient depending on an asphalt amount.

FIG. 5 is a diagram showing a sound absorption coefficient of the present invention.

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Claims (5)

[Claims] 1. A sound absorbing material in which a foam and an asphalt are kneaded and pressed to have a specific gravity of 0.40 to 0.60. 2. The sound absorbing material according to claim 1, wherein the asphalt has a penetration of 60 to 90 and a softening point of 80 to 100 ° C. 3. The sound-absorbing material according to claim 1, wherein the foam is an inorganic foam having a particle size of 1.2 to 2.5 mm. 4. The sound-absorbing material according to claim 1, wherein the foam comprises 75 to 85% by weight and asphalt 25 to 15% by weight. 5. The sound-absorbing material according to claim 1, wherein the surface other than the sound-absorbing surface is covered with a resin.